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START-INFO-DIR-ENTRY
* mysql: (mysql).               MySQL documentation.
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File: manual.info,  Node: Top,  Next: preface,  Prev: (dir),  Up: (dir)

* Menu:

* preface::                      Preface and Legal Notice
* introduction::                 General Information
* installing::                   Installing and Upgrading MySQL
* tutorial::                     Tutorial
* programs::                     MySQL Programs
* server-administration::        MySQL Server Administration
* backup-and-recovery::          Backup and Recovery
* optimization::                 Optimization
* language-structure::           Language Structure
* globalization::                Globalization
* data-types::                   Data Types
* functions::                    Functions and Operators
* sql-syntax::                   SQL Statement Syntax
* storage-engines::              Storage Engines
* ha-overview::                  High Availability and Scalability
* replication::                  Replication
* mysql-cluster::                MySQL Cluster
* stored-programs-views::        Stored Programs and Views
* information-schema::           `INFORMATION_SCHEMA' Tables
* connectors-apis::              Connectors and APIs
* extending-mysql::              Extending MySQL
* mysql-enterprise-monitor::     MySQL Enterprise Monitor
* mysql-enterprise-backup::      MySQL Enterprise Backup
* licenses-third-party::         Licenses for Third-Party Components
* faqs::                         MySQL 5.0 Frequently Asked Questions
* error-handling::               Errors, Error Codes, and Common Problems
* news::                         MySQL Change History
* restrictions::                 Restrictions and Limits


File: manual.info,  Node: preface,  Next: introduction,  Prev: Top,  Up: Top

1 Preface and Legal Notice
**************************

This is the Reference Manual for the MySQL Database System, version
5.0, through release 5.0.95. Differences between minor versions of
MySQL 5.0 are noted in the present text with reference to release
numbers (5.0.X). For license information, see the Legal Notice. This
product may contain third-party code. For license information on
third-party code, see *Note licenses-third-party::.

This manual is not intended for use with older versions of the MySQL
software due to the many functional and other differences between MySQL
5.0 and previous versions. If you are using an earlier release of the
MySQL software, please refer to the appropriate manual. For example,
`MySQL 3.23, 4.0, 4.1 Reference Manual'
(http://dev.mysql.com/doc/refman/4.1/en/), covers the 4.1 series of
MySQL software releases.

If you are using MySQL 5.1, please refer to the `MySQL 5.1 Reference
Manual' (http://dev.mysql.com/doc/refman/5.1/en/).

*Legal Notice*

Copyright (C) 1997, 2011, Oracle and/or its affiliates. All rights
reserved.

This software and related documentation are provided under a license
agreement containing restrictions on use and disclosure and are
protected by intellectual property laws. Except as expressly permitted
in your license agreement or allowed by law, you may not use, copy,
reproduce, translate, broadcast, modify, license, transmit, distribute,
exhibit, perform, publish, or display any part, in any form, or by any
means. Reverse engineering, disassembly, or decompilation of this
software, unless required by law for interoperability, is prohibited.

The information contained herein is subject to change without notice
and is not warranted to be error-free. If you find any errors, please
report them to us in writing.

If this software or related documentation is delivered to the U.S.
Government or anyone licensing it on behalf of the U.S. Government, the
following notice is applicable:

U.S. GOVERNMENT RIGHTS Programs, software, databases, and related
documentation and technical data delivered to U.S. Government customers
are "commercial computer software" or "commercial technical data"
pursuant to the applicable Federal Acquisition Regulation and
agency-specific supplemental regulations. As such, the use,
duplication, disclosure, modification, and adaptation shall be subject
to the restrictions and license terms set forth in the applicable
Government contract, and, to the extent applicable by the terms of the
Government contract, the additional rights set forth in FAR 52.227-19,
Commercial Computer Software License (December 2007).  Oracle USA,
Inc., 500 Oracle Parkway, Redwood City, CA 94065.

This software is developed for general use in a variety of information
management applications. It is not developed or intended for use in any
inherently dangerous applications, including applications which may
create a risk of personal injury. If you use this software in dangerous
applications, then you shall be responsible to take all appropriate
fail-safe, backup, redundancy, and other measures to ensure the safe
use of this software. Oracle Corporation and its affiliates disclaim
any liability for any damages caused by use of this software in
dangerous applications.

Oracle is a registered trademark of Oracle Corporation and/or its
affiliates. MySQL is a trademark of Oracle Corporation and/or its
affiliates, and shall not be used without Oracle's express written
authorization. Other names may be trademarks of their respective owners.

This software and documentation may provide access to or information on
content, products, and services from third parties. Oracle Corporation
and its affiliates are not responsible for and expressly disclaim all
warranties of any kind with respect to third-party content, products,
and services. Oracle Corporation and its affiliates will not be
responsible for any loss, costs, or damages incurred due to your access
to or use of third-party content, products, or services.

This document in any form, software or printed matter, contains
proprietary information that is the exclusive property of Oracle.  Your
access to and use of this material is subject to the terms and
conditions of your Oracle Software License and Service Agreement, which
has been executed and with which you agree to comply. This document and
information contained herein may not be disclosed, copied, reproduced,
or distributed to anyone outside Oracle without prior written consent
of Oracle or as specifically provided below.  This document is not part
of your license agreement nor can it be incorporated into any
contractual agreement with Oracle or its subsidiaries or affiliates.

This documentation is NOT distributed under a GPL license. Use of this
documentation is subject to the following terms:

You may create a printed copy of this documentation solely for your own
personal use. Conversion to other formats is allowed as long as the
actual content is not altered or edited in any way. You shall not
publish or distribute this documentation in any form or on any media,
except if you distribute the documentation in a manner similar to how
Oracle disseminates it (that is, electronically for download on a Web
site with the software) or on a CD-ROM or similar medium, provided
however that the documentation is disseminated together with the
software on the same medium. Any other use, such as any dissemination
of printed copies or use of this documentation, in whole or in part, in
another publication, requires the prior written consent from an
authorized representative of Oracle. Oracle and/or its affiliates
reserve any and all rights to this documentation not expressly granted
above.

For more information on the terms of this license, or for details on
how the MySQL documentation is built and produced, please visit MySQL
Contact & Questions (http://dev.mysql.com/contact/).

For additional licensing information, including licenses for
third-party libraries used by MySQL products, see *Note Top::.

For help with using MySQL, please visit either the MySQL Forums
(http://forums.mysql.com) or MySQL Mailing Lists
(http://lists.mysql.com) where you can discuss your issues with other
MySQL users.

For additional documentation on MySQL products, including translations
of the documentation into other languages, and downloadable versions in
variety of formats, including HTML and PDF formats, see the MySQL
Documentation Library (http://dev.mysql.com/doc).


File: manual.info,  Node: introduction,  Next: installing,  Prev: preface,  Up: Top

2 General Information
*********************

* Menu:

* manual-info::                  About This Manual
* manual-conventions::           Typographical and Syntax Conventions
* what-is::                      Overview of the MySQL Database Management System
* mysql-nutshell::               What Is New in MySQL 5.0
* development-history::          MySQL Development History
* information-sources::          MySQL Information Sources
* bug-reports::                  How to Report Bugs or Problems
* compatibility::                MySQL Standards Compliance
* credits::                      Credits

End of Product Lifecycle

Active development for MySQL Database Server version 5.0 has ended.
Oracle offers various support offerings which may be of interest. For
details and more information, see the MySQL section of the Lifetime
Support Policy for Oracle Technology Products
(http://www.oracle.com/us/support/lifetime-support/index.html). Please
consider upgrading to a recent version.

The MySQL(tm) software delivers a very fast, multi-threaded,
multi-user, and robust SQL (Structured Query Language) database server.
MySQL Server is intended for mission-critical, heavy-load production
systems as well as for embedding into mass-deployed software. Oracle is
a registered trademark of Oracle Corporation and/or its affiliates.
MySQL is a trademark of Oracle Corporation and/or its affiliates, and
shall not be used by Customer without Oracle's express written
authorization. Other names may be trademarks of their respective owners.

The MySQL software is Dual Licensed. Users can choose to use the MySQL
software as an Open Source product under the terms of the GNU General
Public License (`http://www.fsf.org/licenses/') or can purchase a
standard commercial license from Oracle. See
http://www.mysql.com/company/legal/licensing/ for more information on
our licensing policies.

The following list describes some sections of particular interest in
this manual:

   * For a discussion of MySQL Database Server capabilities, see *Note
     features::.

   * For descriptions of new MySQL features, see *Note mysql-nutshell::.

   * For installation instructions, see *Note installing::.  For
     information about upgrading MySQL, see *Note upgrading::, and the
     change notes at *Note news::.

   * For a tutorial introduction to the MySQL Database Server, see
     *Note tutorial::.

   * For information about configuring and administering MySQL Server,
     see *Note server-administration::.

   * For information about setting up replication servers, see *Note
     replication::.

   * For answers to a number of questions that are often asked
     concerning the MySQL Database Server and its capabilities, see
     *Note faqs::.

   * For a history of new features and bugfixes, see *Note news::.

To report errors (often called `bugs'), please use the instructions at
*Note bug-reports::.

If you have found a sensitive security bug in MySQL Server, please let
us know immediately by sending an email message to <security@mysql.com>.


File: manual.info,  Node: manual-info,  Next: manual-conventions,  Prev: introduction,  Up: introduction

2.1 About This Manual
=====================

This is the Reference Manual for the MySQL Database System, version
5.0, through release 5.0.95.  Differences between minor versions of
MySQL 5.0 are noted in the present text with reference to release
numbers (5.0.X).

This manual is not intended for use with older versions of the MySQL
software due to the many functional and other differences between MySQL
5.0 and previous versions. If you are using an earlier release of the
MySQL software, please refer to the appropriate manual. For example,
`MySQL 3.23, 4.0, 4.1 Reference Manual'
(http://dev.mysql.com/doc/refman/4.1/en/), covers the 4.1 series of
MySQL software releases.

If you are using MySQL 5.1, please refer to the `MySQL 5.1 Reference
Manual' (http://dev.mysql.com/doc/refman/5.1/en/).

Because this manual serves as a reference, it does not provide general
instruction on SQL or relational database concepts. It also does not
teach you how to use your operating system or command-line interpreter.

The MySQL Database Software is under constant development, and the
Reference Manual is updated frequently as well. The most recent version
of the manual is available online in searchable form at
`http://dev.mysql.com/doc/'. Other formats also are available there,
including HTML, PDF, and Windows CHM versions.

The Reference Manual source files are written in DocBook XML format.
The HTML version and other formats are produced automatically,
primarily using the DocBook XSL stylesheets. For information about
DocBook, see `http://docbook.org/'

If you have questions about using MySQL, you can ask them using our
mailing lists or forums. See *Note mailing-lists::, and *Note forums::.
If you have suggestions concerning additions or corrections to the
manual itself, please send them to the
http://www.mysql.com/company/contact/.

This manual was originally written by David Axmark and Michael `Monty'
Widenius. It is maintained by the MySQL Documentation Team, consisting
of Paul DuBois, Stefan Hinz, Philip Olson, John Russell, and Jon
Stephens.


File: manual.info,  Node: manual-conventions,  Next: what-is,  Prev: manual-info,  Up: introduction

2.2 Typographical and Syntax Conventions
========================================

This manual uses certain typographical conventions:

   * `Text in this style' is used for SQL statements; database, table,
     and column names; program listings and source code; and
     environment variables. Example: `To reload the grant tables, use
     the *Note `FLUSH PRIVILEGES': flush. statement.'

   * Text in this style indicates input that you type in examples.

   * `Text in this style' indicates the names of executable programs
     and scripts, examples being *Note `mysql': mysql. (the MySQL
     command line client program) and *Note `mysqld': mysqld. (the
     MySQL server executable).

   * TEXT IN THIS STYLE is used for variable input for which you should
     substitute a value of your own choosing.

   * _Text in this style_ is used for emphasis.

   * *Text in this style* is used in table headings and to convey
     especially strong emphasis.

   * `Text in this style' is used to indicate a program option that
     affects how the program is executed, or that supplies information
     that is needed for the program to function in a certain way.
     _Example_: `The `--host' option (short form `-h') tells the *Note
     `mysql': mysql. client program the hostname or IP address of the
     MySQL server that it should connect to'.

   * File names and directory names are written like this: `The global
     `my.cnf' file is located in the `/etc' directory.'

   * Character sequences are written like this: `To specify a wildcard,
     use the ``%'' character.'

When commands are shown that are meant to be executed from within a
particular program, the prompt shown preceding the command indicates
which command to use. For example, `shell>' indicates a command that
you execute from your login shell, `root-shell>' is similar but should
be executed as `root', and `mysql>' indicates a statement that you
execute from the *Note `mysql': mysql. client program:

     shell> type a shell command here
     root-shell> type a shell command as ROOT here
     mysql> type a mysql statement here

In some areas different systems may be distinguished from each other to
show that commands should be executed in two different environments.
For example, while working with replication the commands might be
prefixed with `master' and `slave':

     master> type a mysql command on the replication master here
     slave> type a mysql command on the replication slave here

The `shell' is your command interpreter. On Unix, this is typically a
program such as `sh', `csh', or `bash'. On Windows, the equivalent
program is `command.com' or `cmd.exe', typically run in a console
window.

When you enter a command or statement shown in an example, do not type
the prompt shown in the example.

Database, table, and column names must often be substituted into
statements. To indicate that such substitution is necessary, this
manual uses DB_NAME, TBL_NAME, and COL_NAME. For example, you might see
a statement like this:

     mysql> SELECT COL_NAME FROM DB_NAME.TBL_NAME;

This means that if you were to enter a similar statement, you would
supply your own database, table, and column names, perhaps like this:

     mysql> SELECT author_name FROM biblio_db.author_list;

SQL keywords are not case sensitive and may be written in any
lettercase. This manual uses uppercase.

In syntax descriptions, square brackets (``['' and ``]'') indicate
optional words or clauses. For example, in the following statement, `IF
EXISTS' is optional:

     DROP TABLE [IF EXISTS] TBL_NAME

When a syntax element consists of a number of alternatives, the
alternatives are separated by vertical bars (``|''). When one member
from a set of choices _may_ be chosen, the alternatives are listed
within square brackets (``['' and ``]''):

     TRIM([[BOTH | LEADING | TRAILING] [REMSTR] FROM] STR)

When one member from a set of choices _must_ be chosen, the
alternatives are listed within braces (``{'' and ``}''):

     {DESCRIBE | DESC} TBL_NAME [COL_NAME | WILD]

An ellipsis (`...') indicates the omission of a section of a statement,
typically to provide a shorter version of more complex syntax. For
example, *Note `SELECT ... INTO OUTFILE': select. is shorthand for the
form of *Note `SELECT': select. statement that has an `INTO OUTFILE'
clause following other parts of the statement.

An ellipsis can also indicate that the preceding syntax element of a
statement may be repeated. In the following example, multiple
RESET_OPTION values may be given, with each of those after the first
preceded by commas:

     RESET RESET_OPTION [,RESET_OPTION] ...

Commands for setting shell variables are shown using Bourne shell
syntax. For example, the sequence to set the `CC' environment variable
and run the `configure' command looks like this in Bourne shell syntax:

     shell> CC=gcc ./configure

If you are using `csh' or `tcsh', you must issue commands somewhat
differently:

     shell> setenv CC gcc
     shell> ./configure


File: manual.info,  Node: what-is,  Next: mysql-nutshell,  Prev: manual-conventions,  Up: introduction

2.3 Overview of the MySQL Database Management System
====================================================

* Menu:

* what-is-mysql::                What is MySQL?
* history::                      History of MySQL
* features::                     The Main Features of MySQL


File: manual.info,  Node: what-is-mysql,  Next: history,  Prev: what-is,  Up: what-is

2.3.1 What is MySQL?
--------------------

MySQL, the most popular Open Source SQL database management system, is
developed, distributed, and supported by Oracle Corporation.

The MySQL Web site (http://www.mysql.com/) provides the latest
information about MySQL software.

   * MySQL is a database management system.

     A database is a structured collection of data. It may be anything
     from a simple shopping list to a picture gallery or the vast
     amounts of information in a corporate network. To add, access, and
     process data stored in a computer database, you need a database
     management system such as MySQL Server.  Since computers are very
     good at handling large amounts of data, database management
     systems play a central role in computing, as standalone utilities,
     or as parts of other applications.

   * MySQL is a relational database management system.

     A relational database stores data in separate tables rather than
     putting all the data in one big storeroom. This adds speed and
     flexibility. The SQL part of `MySQL' stands for `Structured Query
     Language.' SQL is the most common standardized language used to
     access databases and is defined by the ANSI/ISO SQL Standard. The
     SQL standard has been evolving since 1986 and several versions
     exist. In this manual, `SQL-92' refers to the standard released in
     1992, `SQL:1999' refers to the standard released in 1999, and
     `SQL:2003' refers to the current version of the standard. We use
     the phrase `the SQL standard' to mean the current version of the
     SQL Standard at any time.

   * MySQL software is Open Source.

     Open Source means that it is possible for anyone to use and modify
     the software. Anybody can download the MySQL software from the
     Internet and use it without paying anything. If you wish, you may
     study the source code and change it to suit your needs. The MySQL
     software uses the GPL (GNU General Public License),
     `http://www.fsf.org/licenses/', to define what you may and may not
     do with the software in different situations. If you feel
     uncomfortable with the GPL or need to embed MySQL code into a
     commercial application, you can buy a commercially licensed
     version from us. See the MySQL Licensing Overview for more
     information (http://www.mysql.com/company/legal/licensing/).

   * The MySQL Database Server is very fast, reliable, and easy to use.

     If that is what you are looking for, you should give it a try.
     MySQL Server also has a practical set of features developed in
     close cooperation with our users. You can find a performance
     comparison of MySQL Server with other database managers on our
     benchmark page. See *Note mysql-benchmarks::.

     MySQL Server was originally developed to handle large databases
     much faster than existing solutions and has been successfully used
     in highly demanding production environments for several years.
     Although under constant development, MySQL Server today offers a
     rich and useful set of functions. Its connectivity, speed, and
     security make MySQL Server highly suited for accessing databases
     on the Internet.

   * MySQL Server works in client/server or embedded systems.

     The MySQL Database Software is a client/server system that
     consists of a multi-threaded SQL server that supports different
     backends, several different client programs and libraries,
     administrative tools, and a wide range of application programming
     interfaces (APIs).

     We also provide MySQL Server as an embedded multi-threaded library
     that you can link into your application to get a smaller, faster,
     easier-to-manage standalone product.

   * A large amount of contributed MySQL software is available.

     It is very likely that your favorite application or language
     supports the MySQL Database Server.

The official way to pronounce `MySQL' is `My Ess Que Ell' (not `my
sequel'), but we do not mind if you pronounce it as `my sequel' or in
some other localized way.


File: manual.info,  Node: history,  Next: features,  Prev: what-is-mysql,  Up: what-is

2.3.2 History of MySQL
----------------------

We started out with the intention of using the `mSQL' database system
to connect to our tables using our own fast low-level (ISAM) routines.
However, after some testing, we came to the conclusion that `mSQL' was
not fast enough or flexible enough for our needs. This resulted in a
new SQL interface to our database but with almost the same API
interface as `mSQL'. This API was designed to enable third-party code
that was written for use with `mSQL' to be ported easily for use with
MySQL.

MySQL is named after co-founder Monty Widenius's daughter, My.

The name of the MySQL Dolphin (our logo) is `Sakila,' which was chosen
from a huge list of names suggested by users in our `Name the Dolphin'
contest. The winning name was submitted by Ambrose Twebaze, an Open
Source software developer from Swaziland, Africa. According to Ambrose,
the feminine name Sakila has its roots in SiSwati, the local language
of Swaziland.  Sakila is also the name of a town in Arusha, Tanzania,
near Ambrose's country of origin, Uganda.


File: manual.info,  Node: features,  Prev: history,  Up: what-is

2.3.3 The Main Features of MySQL
--------------------------------

This section describes some of the important characteristics of the
MySQL Database Software. See also *Note development-history::. In most
respects, the roadmap applies to all versions of MySQL. For information
about features as they are introduced into MySQL on a series-specific
basis, see the `In a Nutshell' section of the appropriate Manual:

   * MySQL 5.0: *Note MySQL 5.0 in a Nutshell: mysql-nutshell.

   * MySQL 5.1: MySQL 5.1 in a Nutshell
     (http://dev.mysql.com/doc/refman/5.1/en/mysql-nutshell.html)

   * MySQL 5.5: MySQL 5.5 in a Nutshell
     (http://dev.mysql.com/doc/refman/5.5/en/mysql-nutshell.html)

Internals and Portability:

   * Written in C and C++.

   * Tested with a broad range of different compilers.

   * Works on many different platforms. See *Note supported-os::.

   * For portability, uses `CMake' in MySQL 5.5 and up. Previous series
     use GNU Automake, Autoconf, and Libtool.

   * Tested with Purify (a commercial memory leakage detector) as well
     as with Valgrind, a GPL tool
     (`http://developer.kde.org/~sewardj/').

   * Uses multi-layered server design with independent modules.

   * Designed to be fully multi-threaded using kernel threads, to
     easily use multiple CPUs if they are available.

   * Provides transactional and nontransactional storage engines.

   * Uses very fast B-tree disk tables (`MyISAM') with index
     compression.

   * Designed to make it relatively easy to add other storage engines.
     This is useful if you want to provide an SQL interface for an
     in-house database.

   * Uses a very fast thread-based memory allocation system.

   * Executes very fast joins using an optimized nested-loop join.

   * Implements in-memory hash tables, which are used as temporary
     tables.

   * Implements SQL functions using a highly optimized class library
     that should be as fast as possible. Usually there is no memory
     allocation at all after query initialization.

   * Provides the server as a separate program for use in a
     client/server networked environment, and as a library that can be
     embedded (linked) into standalone applications. Such applications
     can be used in isolation or in environments where no network is
     available.

Data Types:

   * Many data types: signed/unsigned integers 1, 2, 3, 4, and 8 bytes
     long, *Note `FLOAT': numeric-types, *Note `DOUBLE': numeric-types,
     *Note `CHAR': char, *Note `VARCHAR': char, *Note `BINARY':
     binary-varbinary, *Note `VARBINARY': binary-varbinary, *Note
     `TEXT': blob, *Note `BLOB': blob, *Note `DATE': datetime, *Note
     `TIME': time, *Note `DATETIME': datetime, *Note `TIMESTAMP':
     datetime, *Note `YEAR': year, *Note `SET': set, *Note `ENUM':
     enum, and OpenGIS spatial types. See *Note data-types::.

   * Fixed-length and variable-length string types.

Statements and Functions:

   * Full operator and function support in the *Note `SELECT': select.
     list and `WHERE' clause of queries. For example:

          mysql> SELECT CONCAT(first_name, ' ', last_name)
              -> FROM citizen
              -> WHERE income/dependents > 10000 AND age > 30;

   * Full support for SQL `GROUP BY' and `ORDER BY' clauses. Support
     for group functions (`COUNT()', `AVG()', `STD()', `SUM()', `MAX()',
     `MIN()', and `GROUP_CONCAT()').

   * Support for `LEFT OUTER JOIN' and `RIGHT OUTER JOIN' with both
     standard SQL and ODBC syntax.

   * Support for aliases on tables and columns as required by standard
     SQL.

   * Support for *Note `DELETE': delete, *Note `INSERT': insert, *Note
     `REPLACE': replace, and *Note `UPDATE': update. to return the
     number of rows that were changed (affected), or to return the
     number of rows matched instead by setting a flag when connecting
     to the server.

   * Support for MySQL-specific *Note `SHOW': show.  statements that
     retrieve information about databases, storage engines, tables, and
     indexes. MySQL 5.0 adds support for the `INFORMATION_SCHEMA'
     database, implemented according to standard SQL.

   * An *Note `EXPLAIN': explain. statement to show how the optimizer
     resolves a query.

   * Independence of function names from table or column names. For
     example, `ABS' is a valid column name. The only restriction is
     that for a function call, no spaces are permitted between the
     function name and the ``('' that follows it. See *Note
     reserved-words::.

   * You can refer to tables from different databases in the same
     statement.

Security:

   * A privilege and password system that is very flexible and secure,
     and that enables host-based verification.

   * Password security by encryption of all password traffic when you
     connect to a server.

Scalability and Limits:

   * Support for large databases. We use MySQL Server with databases
     that contain 50 million records. We also know of users who use
     MySQL Server with 200,000 tables and about 5,000,000,000 rows.

   * Support for up to 64 indexes per table (32 before MySQL 4.1.2).
     Each index may consist of 1 to 16 columns or parts of columns. The
     maximum index width is 1000 bytes (767 for `InnoDB'); before MySQL
     4.1.2, the limit is 500 bytes. An index may use a prefix of a
     column for *Note `CHAR': char, *Note `VARCHAR': char, *Note
     `BLOB': blob, or *Note `TEXT': blob. column types.

Connectivity:

   * Clients can connect to MySQL Server using several protocols:

        * Clients can connect using TCP/IP sockets on any platform.

        * On Windows systems in the NT family (NT, 2000, XP, 2003, or
          Vista), clients can connect using named pipes if the server
          is started with the `--enable-named-pipe' option.  In MySQL
          4.1 and higher, Windows servers also support shared-memory
          connections if started with the `--shared-memory' option.
          Clients can connect through shared memory by using the
          `--protocol=memory' option.

        * On Unix systems, clients can connect using Unix domain socket
          files.

   * MySQL client programs can be written in many languages. A client
     library written in C is available for clients written in C or C++,
     or for any language that provides C bindings.

   * APIs for C, C++, Eiffel, Java, Perl, PHP, Python, Ruby, and Tcl
     are available, enabling MySQL clients to be written in many
     languages. See *Note connectors-apis::.

   * The Connector/ODBC (MyODBC) interface provides MySQL support for
     client programs that use ODBC (Open Database Connectivity)
     connections. For example, you can use MS Access to connect to your
     MySQL server. Clients can be run on Windows or Unix.
     Connector/ODBC source is available. All ODBC 2.5 functions are
     supported, as are many others. See *Note connector-odbc::.

   * The Connector/J interface provides MySQL support for Java client
     programs that use JDBC connections. Clients can be run on Windows
     or Unix. Connector/J source is available. See *Note connector-j::.

   * MySQL Connector/Net enables developers to easily create .NET
     applications that require secure, high-performance data
     connectivity with MySQL. It implements the required ADO.NET
     interfaces and integrates into ADO.NET aware tools. Developers can
     build applications using their choice of .NET languages.  MySQL
     Connector/Net is a fully managed ADO.NET driver written in 100%
     pure C#. See *Note connector-net::.

Localization:

   * The server can provide error messages to clients in many
     languages. See *Note error-message-language::.

   * Full support for several different character sets, including
     `latin1' (cp1252), `german', `big5', `ujis', and more.  For
     example, the Scandinavian characters ``aa'', ``a"'' and ``o"'' are
     permitted in table and column names. Unicode support is available
     as of MySQL 4.1.

   * All data is saved in the chosen character set.

   * Sorting and comparisons are done according to the chosen character
     set and collation (using `latin1' and Swedish collation by
     default). It is possible to change this when the MySQL server is
     started. To see an example of very advanced sorting, look at the
     Czech sorting code. MySQL Server supports many different character
     sets that can be specified at compile time and runtime.

   * As of MySQL 4.1, the server time zone can be changed dynamically,
     and individual clients can specify their own time zone. *Note
     time-zone-support::.

Clients and Tools:

   * MySQL includes several client and utility programs. These include
     both command-line programs such as *Note `mysqldump': mysqldump.
     and *Note `mysqladmin': mysqladmin, and graphical programs such as
     MySQL Administrator and MySQL Query Browser.

   * MySQL Server has built-in support for SQL statements to check,
     optimize, and repair tables. These statements are available from
     the command line through the *Note `mysqlcheck': mysqlcheck.
     client. MySQL also includes *Note `myisamchk': myisamchk, a very
     fast command-line utility for performing these operations on
     `MyISAM' tables. See *Note programs::.

   * MySQL programs can be invoked with the `--help' or `-?' option to
     obtain online assistance.


File: manual.info,  Node: mysql-nutshell,  Next: development-history,  Prev: what-is,  Up: introduction

2.4 What Is New in MySQL 5.0
============================

The following features are implemented in MySQL 5.0:

   * Information Schema

     The introduction of the `INFORMATION_SCHEMA' database in MySQL 5.0
     provided a standards-compliant means for accessing the MySQL
     Server's metadata; that is, data about the databases (schemas) on
     the server and the objects which they contain.  See *Note
     information-schema::.

   * Instance Manager

     Can be used to start and stop the MySQL Server, even from a remote
     host. See *Note instance-manager::.

   * Precision Math

     MySQL 5.0 introduced stricter criteria for acceptance or rejection
     of data, and implemented a new library for fixed-point arithmetic.
     These contributed to a much higher degree of accuracy for
     mathematical operations and greater control over invalid values.
     See *Note precision-math::.

   * Storage Engines

     New storage engines were added and performance of others was
     improved.

        * New storage engines in MySQL 5.0 include `ARCHIVE' and
          `FEDERATED'. See *Note archive-storage-engine::, and *Note
          federated-storage-engine::.

        * Performance Improvements in the `InnoDB' Storage Engine:

             * New compact storage format which can save up to 20% of
               the disk space required in previous MySQL/`InnoDB'
               versions.

             * Faster recovery from a failed or aborted *Note `ALTER
               TABLE': alter-table.

             * Faster implementation of *Note `TRUNCATE TABLE':
               truncate-table.

          (See *Note innodb-storage-engine::.)

        * Performance Improvements in the *Note `NDBCLUSTER':
          mysql-cluster. Storage Engine:

             * Faster handling of queries that use `IN' and `BETWEEN'.

             * Condition pushdown: In cases involving the comparison of
               an unindexed column with a constant, this condition is
               `pushed down' to the cluster where it is evaluated in
               all partitions simultaneously, eliminating the need to
               send nonmatching records over the network. This can make
               such queries 10 to 100 times faster than in MySQL 4.1
               Cluster.

               See *Note explain::, for more information.

          (See *Note mysql-cluster::.)

   * Stored Routines

     MySQL 5.0 added support for stored procedures and stored
     functions. See *Note stored-routines::.

   * Triggers

     MySQL 5.0 added limited support for triggers. See *Note triggers::.

   * Views

     MySQL 5.0 added support for named, updatable views. See *Note
     views::.

   * Cursors

     Elementary support for server-side cursors. For information about
     using cursors within stored routines, see *Note cursors::. For
     information about using cursors from within the C API, see *Note
     mysql-stmt-attr-set::.

   * Strict Mode and Standard Error Handling

     MySQL 5.0 added a strict mode where by it follows standard SQL in
     a number of ways in which it did not previously.  Support for
     standard SQLSTATE error messages was also implemented. See *Note
     server-sql-mode::.

   * `VARCHAR' Data Type

     The effective maximum length of a *Note `VARCHAR': char. column
     was increased to 65,535 bytes, and stripping of trailing
     whitespace was eliminated. *Note `VARCHAR': char. in MySQL 5.0 is
     more efficient than in previous versions, due to the elimination
     of the old (and nonstandard) removal of trailing spaces during
     retrieval. (The actual maximum length of a *Note `VARCHAR': char.
     is determined by the maximum row size and the character set you
     use. The maximum _effective_ column length is subject to a row
     size of 65,535 bytes, which is shared among all columns.) See
     *Note string-types::.

   * `BIT' Data Type

     A true *Note `BIT': numeric-types. column type is available that
     can be used to store numbers in binary notation. This type is much
     more efficient for storage and retrieval of Boolean values than
     the workarounds required in MySQL in versions previous to 5.0. See
     *Note numeric-type-overview::.

   * Optimizer enhancements

     Several optimizer improvements were made to improve the speed of
     certain types of queries and in the handling of certain types.
     These include:

        * MySQL 5.0 introduces a new `greedy' optimizer which can
          greatly reduce the time required to arrive at a query
          execution plan. This is particularly noticeable where several
          tables are to be joined and no good join keys can otherwise
          be found. Without the greedy optimizer, the complexity of the
          search for an execution plan is calculated as `N!', where N
          is the number of tables to be joined. The greedy optimizer
          reduces this to `N!/(D-1)!', where D is the depth of the
          search. Although the greedy optimizer does not guarantee the
          best possible of all execution plans (this is currently being
          worked on), it can reduce the time spent arriving at an
          execution plan for a join involving a great many tables--30,
          40, or more--by a factor of as much as 1,000. This should
          eliminate most if not all situations where users thought that
          the optimizer had hung when trying to perform joins across
          many tables.

        * Use of the _Index Merge_ method to obtain better optimization
          of `AND' and `OR' relations over different keys. (Previously,
          these were optimized only where both relations in the `WHERE'
          clause involved the same key.) This also applies to other
          one-to-one comparison operators (`>', `<', and so on),
          including `=' and the `IN' operator. This means that MySQL
          can use multiple indexes in retrieving results for conditions
          such as `WHERE key1 > 4 OR key2 < 7' and even combinations of
          conditions such as `WHERE (key1 > 4 OR key2 < 7) AND (key3 >=
          10 OR key4 = 1)'. See *Note index-merge-optimization::.

        * A new equality detector finds and optimizes `hidden'
          equalities in joins. For example, a `WHERE' clause such as

               t1.c1=t2.c2 AND t2.c2=t3.c3 AND t1.c1 < 5

          implies these other conditions

               t1.c1=t3.c3 AND t2.c2 < 5 AND t3.c3 < 5

          These optimizations can be applied with any combination of
          `AND' and `OR' operators. See *Note
          nested-join-optimization::, and *Note
          outer-join-simplification::.

        * Optimization of `NOT IN' and `NOT BETWEEN' relations,
          reducing or eliminating table scans for queries making use of
          them by mean of range analysis. The performance of MySQL with
          regard to these relations now matches its performance with
          regard to `IN' and `BETWEEN'.

   * XA Transactions

     MySQL 5.0 supports XA (distributed) transactions. See *Note xa::.


File: manual.info,  Node: development-history,  Next: information-sources,  Prev: mysql-nutshell,  Up: introduction

2.5 MySQL Development History
=============================

This section describes the general MySQL development history, including
major features implemented in or planned for various MySQL releases.
The following sections provide information for each release series.

The current production release series is MySQL 5.1, which was declared
stable for production use as of MySQL 5.1.30, released in November
2008. The previous production release series was MySQL 5.0, which was
declared stable for production use as of MySQL 5.0.15, released in
October 2005. `General Availability status' means that future 5.1 and
5.0 development is limited only to bugfixes. For the older MySQL 4.1,
4.0, and 3.23 series, only critical bugfixes are made.

Before upgrading from one release series to the next, please see the
notes in *Note upgrading::.

The most requested features and the versions in which they were
implemented are summarized in the following table.

Feature                MySQL Series
Unions                 4.0
Subqueries             4.1
R-trees                4.1 (for the `MyISAM' storage engine)
Stored procedures and  5.0
functions              
Views                  5.0
Cursors                5.0
XA transactions        5.0
Triggers               5.0 and 5.1
Event scheduler        5.1
Partitioning           5.1
Pluggable storage      5.1
engine API             
Plugin API             5.1
InnoDB Plugin          5.1
Row-based replication  5.1
Server log tables      5.1


File: manual.info,  Node: information-sources,  Next: bug-reports,  Prev: development-history,  Up: introduction

2.6 MySQL Information Sources
=============================

* Menu:

* mailing-lists::                MySQL Mailing Lists
* forums::                       MySQL Community Support at the MySQL Forums
* irc::                          MySQL Community Support on Internet Relay Chat (IRC)
* mysql-enterprise-information::  MySQL Enterprise

This section lists sources of additional information that you may find
helpful, such as the MySQL mailing lists and user forums, and Internet
Relay Chat.


File: manual.info,  Node: mailing-lists,  Next: forums,  Prev: information-sources,  Up: information-sources

2.6.1 MySQL Mailing Lists
-------------------------

* Menu:

* mailing-list-use::             Guidelines for Using the Mailing Lists

This section introduces the MySQL mailing lists and provides guidelines
as to how the lists should be used. When you subscribe to a mailing
list, you receive all postings to the list as email messages. You can
also send your own questions and answers to the list.

To subscribe to or unsubscribe from any of the mailing lists described
in this section, visit `http://lists.mysql.com/'. For most of them, you
can select the regular version of the list where you get individual
messages, or a digest version where you get one large message per day.

Please _do not_ send messages about subscribing or unsubscribing to any
of the mailing lists, because such messages are distributed
automatically to thousands of other users.

Your local site may have many subscribers to a MySQL mailing list.  If
so, the site may have a local mailing list, so that messages sent from
`lists.mysql.com' to your site are propagated to the local list. In
such cases, please contact your system administrator to be added to or
dropped from the local MySQL list.

To have traffic for a mailing list go to a separate mailbox in your
mail program, set up a filter based on the message headers.  You can
use either the `List-ID:' or `Delivered-To:' headers to identify list
messages.

The MySQL mailing lists are as follows:

   * `announce'

     The list for announcements of new versions of MySQL and related
     programs. This is a low-volume list to which all MySQL users
     should subscribe.

   * `mysql'

     The main list for general MySQL discussion. Please note that some
     topics are better discussed on the more-specialized lists. If you
     post to the wrong list, you may not get an answer.

   * `bugs'

     The list for people who want to stay informed about issues
     reported since the last release of MySQL or who want to be
     actively involved in the process of bug hunting and fixing.  See
     *Note bug-reports::.

   * `internals'

     The list for people who work on the MySQL code. This is also the
     forum for discussions on MySQL development and for posting patches.

   * `mysqldoc'

     The list for people who work on the MySQL documentation.

   * `benchmarks'

     The list for anyone interested in performance issues.  Discussions
     concentrate on database performance (not limited to MySQL), but
     also include broader categories such as performance of the kernel,
     file system, disk system, and so on.

   * `packagers'

     The list for discussions on packaging and distributing MySQL.
     This is the forum used by distribution maintainers to exchange
     ideas on packaging MySQL and on ensuring that MySQL looks and
     feels as similar as possible on all supported platforms and
     operating systems.

   * `java'

     The list for discussions about the MySQL server and Java. It is
     mostly used to discuss JDBC drivers such as MySQL Connector/J.

   * `win32'

     The list for all topics concerning the MySQL software on Microsoft
     operating systems, such as Windows 9x, Me, NT, 2000, XP, and 2003.

   * `myodbc'

     The list for all topics concerning connecting to the MySQL server
     with ODBC.

   * `gui-tools'

     The list for all topics concerning MySQL graphical user interface
     tools such as `MySQL Administrator' and `MySQL Query Browser'.

   * `cluster'

     The list for discussion of MySQL Cluster.

   * `dotnet'

     The list for discussion of the MySQL server and the .NET platform.
     It is mostly related to MySQL Connector/Net.

   * `plusplus'

     The list for all topics concerning programming with the C++ API
     for MySQL.

   * `perl'

     The list for all topics concerning Perl support for MySQL with
     `DBD::mysql'.

If you're unable to get an answer to your questions from a MySQL
mailing list or forum, one option is to purchase support from Oracle.
This puts you in direct contact with MySQL developers.

The following MySQL mailing lists are in languages other than English.
These lists are not operated by Oracle.

   * `<mysql-france-subscribe@yahoogroups.com>'

     A French mailing list.

   * `<list@tinc.net>'

     A Korean mailing list. To subscribe, email `subscribe mysql
     your@email.address' to this list.

   * `<mysql-de-request@lists.4t2.com>'

     A German mailing list. To subscribe, email `subscribe mysql-de
     your@email.address' to this list. You can find information about
     this mailing list at `http://www.4t2.com/mysql/'.

   * `<mysql-br-request@listas.linkway.com.br>'

     A Portuguese mailing list. To subscribe, email `subscribe mysql-br
     your@email.address' to this list.

   * `<mysql-alta@elistas.net>'

     A Spanish mailing list. To subscribe, email `subscribe mysql
     your@email.address' to this list.


File: manual.info,  Node: mailing-list-use,  Prev: mailing-lists,  Up: mailing-lists

2.6.1.1 Guidelines for Using the Mailing Lists
..............................................

Please do not post mail messages from your browser with HTML mode
turned on. Many users do not read mail with a browser.

When you answer a question sent to a mailing list, if you consider your
answer to have broad interest, you may want to post it to the list
instead of replying directly to the individual who asked. Try to make
your answer general enough that people other than the original poster
may benefit from it.  When you post to the list, please make sure that
your answer is not a duplication of a previous answer.

Try to summarize the essential part of the question in your reply. Do
not feel obliged to quote the entire original message.

When answers are sent to you individually and not to the mailing list,
it is considered good etiquette to summarize the answers and send the
summary to the mailing list so that others may have the benefit of
responses you received that helped you solve your problem.


File: manual.info,  Node: forums,  Next: irc,  Prev: mailing-lists,  Up: information-sources

2.6.2 MySQL Community Support at the MySQL Forums
-------------------------------------------------

The forums at `http://forums.mysql.com' are an important community
resource. Many forums are available, grouped into these general
categories:

   * Migration

   * MySQL Usage

   * MySQL Connectors

   * Programming Languages

   * Tools

   * 3rd-Party Applications

   * Storage Engines

   * MySQL Technology

   * SQL Standards

   * Business


File: manual.info,  Node: irc,  Next: mysql-enterprise-information,  Prev: forums,  Up: information-sources

2.6.3 MySQL Community Support on Internet Relay Chat (IRC)
----------------------------------------------------------

In addition to the various MySQL mailing lists and forums, you can find
experienced community people on Internet Relay Chat (IRC).  These are
the best networks/channels currently known to us:

*freenode* (see `http://www.freenode.net/' for servers)

   * `#mysql' is primarily for MySQL questions, but other database and
     general SQL questions are welcome.  Questions about PHP, Perl, or
     C in combination with MySQL are also common.

If you are looking for IRC client software to connect to an IRC
network, take a look at `xChat' (`http://www.xchat.org/'). X-Chat (GPL
licensed) is available for Unix as well as for Windows platforms (a free
Windows build of X-Chat is available at
`http://www.silverex.org/download/').


File: manual.info,  Node: mysql-enterprise-information,  Prev: irc,  Up: information-sources

2.6.4 MySQL Enterprise
----------------------

Oracle offers technical support in the form of MySQL Enterprise.  For
organizations that rely on the MySQL DBMS for business-critical
production applications, MySQL Enterprise is a commercial subscription
offering which includes:

   * MySQL Enterprise Server

   * MySQL Enterprise Monitor

   * Monthly Rapid Updates and Quarterly Service Packs

   * MySQL Knowledge Base

   * 24x7 Technical and Consultative Support

MySQL Enterprise is available in multiple tiers, giving you the
flexibility to choose the level of service that best matches your
needs. For more information, see MySQL Enterprise
(http://www.mysql.com/products/enterprise/).


File: manual.info,  Node: bug-reports,  Next: compatibility,  Prev: information-sources,  Up: introduction

2.7 How to Report Bugs or Problems
==================================

Before posting a bug report about a problem, please try to verify that
it is a bug and that it has not been reported already:

   * Start by searching the MySQL online manual at
     `http://dev.mysql.com/doc/'. We try to keep the manual up to date
     by updating it frequently with solutions to newly found problems.
     The change history (`http://dev.mysql.com/doc/mysql/en/news.html')
     can be particularly useful since it is quite possible that a newer
     version contains a solution to your problem.

   * If you get a parse error for an SQL statement, please check your
     syntax closely. If you cannot find something wrong with it, it is
     extremely likely that your current version of MySQL Server doesn't
     support the syntax you are using. If you are using the current
     version and the manual doesn't cover the syntax that you are
     using, MySQL Server doesn't support your statement. In this case,
     your options are to implement the syntax yourself or email
     <licensing@mysql.com> and ask for an offer to implement it.

     If the manual covers the syntax you are using, but you have an
     older version of MySQL Server, you should check the MySQL change
     history to see when the syntax was implemented. In this case, you
     have the option of upgrading to a newer version of MySQL Server.

   * For solutions to some common problems, see *Note problems::.

   * Search the bugs database at `http://bugs.mysql.com/' to see
     whether the bug has been reported and fixed.

   * Search the MySQL mailing list archives at
     `http://lists.mysql.com/'. See *Note mailing-lists::.

   * You can also use http://www.mysql.com/search/ to search all the
     Web pages (including the manual) that are located at the MySQL Web
     site.

If you cannot find an answer in the manual, the bugs database, or the
mailing list archives, check with your local MySQL expert. If you still
cannot find an answer to your question, please use the following
guidelines for reporting the bug.

The normal way to report bugs is to visit `http://bugs.mysql.com/',
which is the address for our bugs database. This database is public and
can be browsed and searched by anyone. If you log in to the system, you
can enter new reports.

Bugs posted in the bugs database at `http://bugs.mysql.com/' that are
corrected for a given release are noted in the change history.

If you have found a sensitive security bug in MySQL, you can send email
to <security@mysql.com>.

To discuss problems with other users, you can use one of the MySQL
mailing lists. *Note mailing-lists::.

Writing a good bug report takes patience, but doing it right the first
time saves time both for us and for yourself. A good bug report,
containing a full test case for the bug, makes it very likely that we
will fix the bug in the next release. This section helps you write your
report correctly so that you do not waste your time doing things that
may not help us much or at all. Please read this section carefully and
make sure that all the information described here is included in your
report.

Preferably, you should test the problem using the latest production or
development version of MySQL Server before posting. Anyone should be
able to repeat the bug by just using `mysql test < script_file' on your
test case or by running the shell or Perl script that you include in
the bug report. Any bug that we are able to repeat has a high chance of
being fixed in the next MySQL release.

It is most helpful when a good description of the problem is included
in the bug report. That is, give a good example of everything you did
that led to the problem and describe, in exact detail, the problem
itself. The best reports are those that include a full example showing
how to reproduce the bug or problem. See MySQL Internals: Porting
(http://forge.mysql.com/wiki/MySQL_Internals_Porting).

Remember that it is possible for us to respond to a report containing
too much information, but not to one containing too little. People
often omit facts because they think they know the cause of a problem
and assume that some details do not matter. A good principle to follow
is that if you are in doubt about stating something, state it. It is
faster and less troublesome to write a couple more lines in your report
than to wait longer for the answer if we must ask you to provide
information that was missing from the initial report.

The most common errors made in bug reports are (a) not including the
version number of the MySQL distribution that you use, and (b) not
fully describing the platform on which the MySQL server is installed
(including the platform type and version number). These are highly
relevant pieces of information, and in 99 cases out of 100, the bug
report is useless without them. Very often we get questions like, `Why
doesn't this work for me?' Then we find that the feature requested
wasn't implemented in that MySQL version, or that a bug described in a
report has been fixed in newer MySQL versions.  Errors often are
platform-dependent. In such cases, it is next to impossible for us to
fix anything without knowing the operating system and the version
number of the platform.

If you compiled MySQL from source, remember also to provide information
about your compiler if it is related to the problem.  Often people find
bugs in compilers and think the problem is MySQL-related. Most
compilers are under development all the time and become better version
by version. To determine whether your problem depends on your compiler,
we need to know what compiler you used.  Note that every compiling
problem should be regarded as a bug and reported accordingly.

If a program produces an error message, it is very important to include
the message in your report. If we try to search for something from the
archives, it is better that the error message reported exactly matches
the one that the program produces. (Even the lettercase should be
observed.) It is best to copy and paste the entire error message into
your report. You should never try to reproduce the message from memory.

If you have a problem with Connector/ODBC (MyODBC), please try to
generate a trace file and send it with your report. See *Note
connector-odbc-support-bug-report::.

If your report includes long query output lines from test cases that
you run with the *Note `mysql': mysql. command-line tool, you can make
the output more readable by using the `--vertical' option or the `\G'
statement terminator. The *Note `EXPLAIN SELECT': explain.  example
later in this section demonstrates the use of `\G'.

Please include the following information in your report:

   * The version number of the MySQL distribution you are using (for
     example, MySQL 5.0.19). You can find out which version you are
     running by executing *Note `mysqladmin version': mysqladmin. The
     *Note `mysqladmin': mysqladmin. program can be found in the `bin'
     directory under your MySQL installation directory.

   * The manufacturer and model of the machine on which you experience
     the problem.

   * The operating system name and version. If you work with Windows,
     you can usually get the name and version number by double-clicking
     your My Computer icon and pulling down the `Help/About Windows'
     menu. For most Unix-like operating systems, you can get this
     information by executing the command `uname -a'.

   * Sometimes the amount of memory (real and virtual) is relevant.  If
     in doubt, include these values.

   * If you are using a source distribution of the MySQL software,
     include the name and version number of the compiler that you used.
     If you have a binary distribution, include the distribution name.

   * If the problem occurs during compilation, include the exact error
     messages and also a few lines of context around the offending code
     in the file where the error occurs.

   * If *Note `mysqld': mysqld. died, you should also report the
     statement that crashed *Note `mysqld': mysqld. You can usually get
     this information by running *Note `mysqld': mysqld. with query
     logging enabled, and then looking in the log after *Note `mysqld':
     mysqld. crashes. See MySQL Internals: Porting
     (http://forge.mysql.com/wiki/MySQL_Internals_Porting).

   * If a database table is related to the problem, include the output
     from the `SHOW CREATE TABLE DB_NAME.TBL_NAME' statement in the bug
     report. This is a very easy way to get the definition of any table
     in a database. The information helps us create a situation
     matching the one that you have experienced.

   * The SQL mode in effect when the problem occurred can be
     significant, so please report the value of the `sql_mode' system
     variable. For stored procedure, stored function, and trigger
     objects, the relevant `sql_mode' value is the one in effect when
     the object was created. For a stored procedure or function, the
     *Note `SHOW CREATE PROCEDURE': show-create-procedure. or *Note
     `SHOW CREATE FUNCTION': show-create-function. statement shows the
     relevant SQL mode, or you can query `INFORMATION_SCHEMA' for the
     information:

          SELECT ROUTINE_SCHEMA, ROUTINE_NAME, SQL_MODE
          FROM INFORMATION_SCHEMA.ROUTINES;

     For triggers, you can use this statement:

          SELECT EVENT_OBJECT_SCHEMA, EVENT_OBJECT_TABLE, TRIGGER_NAME, SQL_MODE
          FROM INFORMATION_SCHEMA.TRIGGERS;

   * For performance-related bugs or problems with *Note `SELECT':
     select. statements, you should always include the output of
     `EXPLAIN SELECT ...', and at least the number of rows that the
     *Note `SELECT': select. statement produces. You should also
     include the output from `SHOW CREATE TABLE TBL_NAME' for each table
     that is involved. The more information you provide about your
     situation, the more likely it is that someone can help you.

     The following is an example of a very good bug report. The
     statements are run using the *Note `mysql': mysql.  command-line
     tool. Note the use of the `\G' statement terminator for statements
     that would otherwise provide very long output lines that are
     difficult to read.

          mysql> SHOW VARIABLES;
          mysql> SHOW COLUMNS FROM ...\G
                 <OUTPUT FROM SHOW COLUMNS>
          mysql> EXPLAIN SELECT ...\G
                 <OUTPUT FROM EXPLAIN>
          mysql> FLUSH STATUS;
          mysql> SELECT ...;
                 <A SHORT VERSION OF THE OUTPUT FROM SELECT,
                 INCLUDING THE TIME TAKEN TO RUN THE QUERY>
          mysql> SHOW STATUS;
                 <OUTPUT FROM SHOW STATUS>

   * If a bug or problem occurs while running *Note `mysqld': mysqld,
     try to provide an input script that reproduces the anomaly. This
     script should include any necessary source files. The more closely
     the script can reproduce your situation, the better. If you can
     make a reproducible test case, you should upload it to be attached
     to the bug report.

     If you cannot provide a script, you should at least include the
     output from *Note `mysqladmin variables extended-status
     processlist': mysqladmin. in your report to provide some
     information on how your system is performing.

   * If you cannot produce a test case with only a few rows, or if the
     test table is too big to be included in the bug report (more than
     10 rows), you should dump your tables using *Note `mysqldump':
     mysqldump. and create a `README' file that describes your problem.
     Create a compressed archive of your files using `tar' and `gzip' or
     `zip', and use FTP to transfer the archive to
     `ftp://ftp.mysql.com/pub/mysql/upload/'. Then enter the problem
     into our bugs database at `http://bugs.mysql.com/'.

   * If you believe that the MySQL server produces a strange result
     from a statement, include not only the result, but also your
     opinion of what the result should be, and an explanation
     describing the basis for your opinion.

   * When you provide an example of the problem, it is better to use
     the table names, variable names, and so forth that exist in your
     actual situation than to come up with new names. The problem could
     be related to the name of a table or variable. These cases are
     rare, perhaps, but it is better to be safe than sorry. After all,
     it should be easier for you to provide an example that uses your
     actual situation, and it is by all means better for us. If you
     have data that you do not want to be visible to others in the bug
     report, you can use FTP to transfer it to
     `ftp://ftp.mysql.com/pub/mysql/upload/'. If the information is
     really top secret and you do not want to show it even to us, go
     ahead and provide an example using other names, but please regard
     this as the last choice.

   * Include all the options given to the relevant programs, if
     possible. For example, indicate the options that you use when you
     start the *Note `mysqld': mysqld. server, as well as the options
     that you use to run any MySQL client programs. The options to
     programs such as *Note `mysqld': mysqld. and *Note `mysql': mysql,
     and to the `configure' script, are often key to resolving problems
     and are very relevant. It is never a bad idea to include them. If
     your problem involves a program written in a language such as Perl
     or PHP, please include the language processor's version number, as
     well as the version for any modules that the program uses. For
     example, if you have a Perl script that uses the `DBI' and
     `DBD::mysql' modules, include the version numbers for Perl, `DBI',
     and `DBD::mysql'.

   * If your question is related to the privilege system, please
     include the output of *Note `mysqlaccess': mysqlaccess, the output
     of *Note `mysqladmin reload': mysqladmin, and all the error
     messages you get when trying to connect. When you test your
     privileges, you should first run *Note `mysqlaccess': mysqlaccess.
     After this, execute *Note `mysqladmin reload version': mysqladmin.
     and try to connect with the program that gives you trouble.  *Note
     `mysqlaccess': mysqlaccess. can be found in the `bin' directory
     under your MySQL installation directory.

   * If you have a patch for a bug, do include it. But do not assume
     that the patch is all we need, or that we can use it, if you do
     not provide some necessary information such as test cases showing
     the bug that your patch fixes. We might find problems with your
     patch or we might not understand it at all. If so, we cannot use
     it.

     If we cannot verify the exact purpose of the patch, we will not
     use it. Test cases help us here. Show that the patch handles all
     the situations that may occur. If we find a borderline case (even
     a rare one) where the patch will not work, it may be useless.

   * Guesses about what the bug is, why it occurs, or what it depends
     on are usually wrong. Even the MySQL team cannot guess such things
     without first using a debugger to determine the real cause of a
     bug.

   * Indicate in your bug report that you have checked the reference
     manual and mail archive so that others know you have tried to
     solve the problem yourself.

   * If the problem is that your data appears corrupt or you get errors
     when you access a particular table, you should first check your
     tables and then try to repair them with *Note `CHECK TABLE':
     check-table. and *Note `REPAIR TABLE': repair-table. or with *Note
     `myisamchk': myisamchk. See *Note server-administration::.

     If you are running Windows, please verify the value of
     `lower_case_table_names' using the `SHOW VARIABLES LIKE
     'lower_case_table_names'' statement. This variable affects how the
     server handles lettercase of database and table names. Its effect
     for a given value should be as described in *Note
     identifier-case-sensitivity::.

   * If you often get corrupted tables, you should try to find out when
     and why this happens. In this case, the error log in the MySQL
     data directory may contain some information about what happened.
     (This is the file with the `.err' suffix in the name.) See *Note
     error-log::. Please include any relevant information from this
     file in your bug report. Normally *Note `mysqld': mysqld. should
     _never_ crash a table if nothing killed it in the middle of an
     update. If you can find the cause of *Note `mysqld': mysqld.
     dying, it is much easier for us to provide you with a fix for the
     problem. See *Note what-is-crashing::.

   * If possible, download and install the most recent version of MySQL
     Server and check whether it solves your problem. All versions of
     the MySQL software thoroughly tested and should work without
     problems. We believe in making everything as backward-compatible
     as possible, and you should be able to switch MySQL versions
     without difficulty. See *Note which-version::.


File: manual.info,  Node: compatibility,  Next: credits,  Prev: bug-reports,  Up: introduction

2.8 MySQL Standards Compliance
==============================

* Menu:

* standards::                    What Standards MySQL Follows
* sql-mode::                     Selecting SQL Modes
* ansi-mode::                    Running MySQL in ANSI Mode
* extensions-to-ansi::           MySQL Extensions to Standard SQL
* differences-from-ansi::        MySQL Differences from Standard SQL
* constraints::                  How MySQL Deals with Constraints

This section describes how MySQL relates to the ANSI/ISO SQL standards.
MySQL Server has many extensions to the SQL standard, and here you can
find out what they are and how to use them. You can also find
information about functionality missing from MySQL Server, and how to
work around some of the differences.

The SQL standard has been evolving since 1986 and several versions
exist. In this manual, `SQL-92' refers to the standard released in
1992, `SQL:1999' refers to the standard released in 1999, `SQL:2003'
refers to the standard released in 2003, and `SQL:2008' refers to the
most recent version of the standard, released in 2008. We use the
phrase `the SQL standard' or `standard SQL' to mean the current version
of the SQL Standard at any time.

One of our main goals with the product is to continue to work toward
compliance with the SQL standard, but without sacrificing speed or
reliability. We are not afraid to add extensions to SQL or support for
non-SQL features if this greatly increases the usability of MySQL
Server for a large segment of our user base.  The *Note `HANDLER':
handler. interface is an example of this strategy. See *Note handler::.

We continue to support transactional and nontransactional databases to
satisfy both mission-critical 24/7 usage and heavy Web or logging usage.

MySQL Server was originally designed to work with medium-sized
databases (10-100 million rows, or about 100MB per table) on small
computer systems. Today MySQL Server handles terabyte-sized databases,
but the code can also be compiled in a reduced version suitable for
hand-held and embedded devices. The compact design of the MySQL server
makes development in both directions possible without any conflicts in
the source tree.

Currently, we are not targeting real-time support, although MySQL
replication capabilities offer significant functionality.

MySQL supports high-availability database clustering using the *Note
`NDBCLUSTER': mysql-cluster. storage engine. See *Note mysql-cluster::.

XML support is to be implemented in a future version of the database
server.


File: manual.info,  Node: standards,  Next: sql-mode,  Prev: compatibility,  Up: compatibility

2.8.1 What Standards MySQL Follows
----------------------------------

Our aim is to support the full ANSI/ISO SQL standard, but without
making concessions to speed and quality of the code.

ODBC levels 0 to 3.51.


File: manual.info,  Node: sql-mode,  Next: ansi-mode,  Prev: standards,  Up: compatibility

2.8.2 Selecting SQL Modes
-------------------------

The MySQL server can operate in different SQL modes, and can apply
these modes differentially for different clients. This capability
enables each application to tailor the server's operating mode to its
own requirements.

SQL modes control aspects of server operation such as what SQL syntax
MySQL should support and what kind of data validation checks it should
perform. This makes it easier to use MySQL in different environments
and to use MySQL together with other database servers.

You can set the default SQL mode by starting *Note `mysqld': mysqld.
with the `--sql-mode="MODE_VALUE"' option. You can also change the mode
at runtime by setting the `sql_mode' system variable with a *Note `SET
[GLOBAL|SESSION] sql_mode='MODE_VALUE'': set-option.  statement.

For more information on setting the SQL mode, see *Note
server-sql-mode::.


File: manual.info,  Node: ansi-mode,  Next: extensions-to-ansi,  Prev: sql-mode,  Up: compatibility

2.8.3 Running MySQL in ANSI Mode
--------------------------------

You can tell *Note `mysqld': mysqld. to run in ANSI mode with the
`--ansi' startup option.  Running the server in ANSI mode is the same
as starting it with the following options:

     --transaction-isolation=SERIALIZABLE --sql-mode=ANSI

You can achieve the same effect at runtime by executing these two
statements:

     SET GLOBAL TRANSACTION ISOLATION LEVEL SERIALIZABLE;
     SET GLOBAL sql_mode = 'ANSI';

You can see that setting the `sql_mode' system variable to `'ANSI''
enables all SQL mode options that are relevant for ANSI mode as follows:

     mysql> SET GLOBAL sql_mode='ANSI';
     mysql> SELECT @@global.sql_mode;
             -> 'REAL_AS_FLOAT,PIPES_AS_CONCAT,ANSI_QUOTES,IGNORE_SPACE,ANSI'

Running the server in ANSI mode with `--ansi' is not quite the same as
setting the SQL mode to `'ANSI''. The `--ansi' option affects the SQL
mode and also sets the transaction isolation level. Setting the SQL
mode to `'ANSI'' has no effect on the isolation level.

See *Note server-options::, and *Note sql-mode::.


File: manual.info,  Node: extensions-to-ansi,  Next: differences-from-ansi,  Prev: ansi-mode,  Up: compatibility

2.8.4 MySQL Extensions to Standard SQL
--------------------------------------

MySQL Server supports some extensions that you probably won't find in
other SQL DBMSs. Be warned that if you use them, your code won't be
portable to other SQL servers. In some cases, you can write code that
includes MySQL extensions, but is still portable, by using comments of
the following form:

     /*! MYSQL-SPECIFIC CODE */

In this case, MySQL Server parses and executes the code within the
comment as it would any other SQL statement, but other SQL servers will
ignore the extensions. For example, MySQL Server recognizes the
`STRAIGHT_JOIN' keyword in the following statement, but other servers
will not:

     SELECT /*! STRAIGHT_JOIN */ col1 FROM table1,table2 WHERE ...

If you add a version number after the ``!'' character, the syntax within
the comment is executed only if the MySQL version is greater than or
equal to the specified version number. The `TEMPORARY' keyword in the
following comment is executed only by servers from MySQL 3.23.02 or
higher:

     CREATE /*!32302 TEMPORARY */ TABLE t (a INT);

The following descriptions list MySQL extensions, organized by category.

   * Organization of data on disk

     MySQL Server maps each database to a directory under the MySQL
     data directory, and maps tables within a database to file names in
     the database directory. This has a few implications:

        * Database and table names are case sensitive in MySQL Server
          on operating systems that have case-sensitive file names
          (such as most Unix systems). See *Note
          identifier-case-sensitivity::.

        * You can use standard system commands to back up, rename,
          move, delete, and copy tables that are managed by the
          `MyISAM' storage engine. For example, it is possible to
          rename a `MyISAM' table by renaming the `.MYD', `.MYI', and
          `.frm' files to which the table corresponds. (Nevertheless, it
          is preferable to use *Note `RENAME TABLE': rename-table. or
          `ALTER TABLE ...  RENAME' and let the server rename the
          files.)

     Database and table names cannot contain path name separator
     characters (``/'', ``\'').

   * General language syntax

        * By default, strings can be enclosed by either ``"'' or ``''',
          not just by ``'''. (If the `ANSI_QUOTES' SQL mode is enabled,
          strings can be enclosed only by ``''' and the server
          interprets strings enclosed by ``"'' as identifiers.)

        * ``\'' is the escape character in strings.

        * In SQL statements, you can access tables from different
          databases with the DB_NAME.TBL_NAME syntax. Some SQL servers
          provide the same functionality but call this `User space'.
          MySQL Server doesn't support tablespaces such as used in
          statements like this: `CREATE TABLE ralph.my_table ... IN
          my_tablespace'.

   * SQL statement syntax

        * The *Note `ANALYZE TABLE': analyze-table, *Note `CHECK
          TABLE': check-table, *Note `OPTIMIZE TABLE': optimize-table,
          and *Note `REPAIR TABLE': repair-table. statements.

        * The *Note `CREATE DATABASE': create-database, *Note `DROP
          DATABASE': drop-database, and *Note `ALTER DATABASE':
          alter-database.  statements. See *Note create-database::,
          *Note drop-database::, and *Note alter-database::.

        * The *Note `DO': do. statement.

        * *Note `EXPLAIN SELECT': explain. to obtain a description of
          how tables are processed by the query optimizer.

        * The *Note `FLUSH': flush. and *Note `RESET': reset.
          statements.

        * The *Note `SET': set-option.  statement. See *Note
          set-option::.

        * The *Note `SHOW': show. statement. See *Note show::. The
          information produced by many of the MySQL-specific *Note
          `SHOW': show. statements can be obtained in more standard
          fashion by using *Note `SELECT': select. to query
          `INFORMATION_SCHEMA'. See *Note information-schema::.

        * Use of *Note `LOAD DATA INFILE': load-data. In many cases,
          this syntax is compatible with Oracle's *Note `LOAD DATA
          INFILE': load-data. See *Note load-data::.

        * Use of *Note `RENAME TABLE': rename-table. See *Note
          rename-table::.

        * Use of *Note `REPLACE': replace. instead of *Note `DELETE':
          delete. plus *Note `INSERT': insert. See *Note replace::.

        * Use of `CHANGE COL_NAME', `DROP COL_NAME', or *Note `DROP
          INDEX': drop-index, `IGNORE' or `RENAME' in *Note `ALTER
          TABLE': alter-table.  statements. Use of multiple `ADD',
          `ALTER', `DROP', or `CHANGE' clauses in an *Note `ALTER
          TABLE': alter-table. statement.  See *Note alter-table::.

        * Use of index names, indexes on a prefix of a column, and use
          of `INDEX' or `KEY' in *Note `CREATE TABLE': create-table.
          statements. See *Note create-table::.

        * Use of `TEMPORARY' or `IF NOT EXISTS' with *Note `CREATE
          TABLE': create-table.

        * Use of `IF EXISTS' with *Note `DROP TABLE': drop-table. and
          *Note `DROP DATABASE': drop-database.

        * The capability of dropping multiple tables with a single
          *Note `DROP TABLE': drop-table. statement.

        * The `ORDER BY' and `LIMIT' clauses of the *Note `UPDATE':
          update. and *Note `DELETE': delete. statements.

        * `INSERT INTO TBL_NAME SET COL_NAME = ...' syntax.

        * The `DELAYED' clause of the *Note `INSERT': insert. and *Note
          `REPLACE': replace. statements.

        * The `LOW_PRIORITY' clause of the *Note `INSERT': insert,
          *Note `REPLACE': replace, *Note `DELETE': delete, and *Note
          `UPDATE': update. statements.

        * Use of `INTO OUTFILE' or `INTO DUMPFILE' in *Note `SELECT':
          select. statements. See *Note select::.

        * Options such as `STRAIGHT_JOIN' or `SQL_SMALL_RESULT' in
          *Note `SELECT': select. statements.

        * You don't need to name all selected columns in the `GROUP BY'
          clause. This gives better performance for some very specific,
          but quite normal queries. See *Note
          group-by-functions-and-modifiers::.

        * You can specify `ASC' and `DESC' with `GROUP BY', not just
          with `ORDER BY'.

        * The ability to set variables in a statement with the `:='
          assignment operator. See *Note user-variables::.

   * Data types

        * The *Note `MEDIUMINT': numeric-types, *Note `SET': set, and
          *Note `ENUM': enum. data types, and the various *Note `BLOB':
          blob. and *Note `TEXT': blob. data types.

        * The `AUTO_INCREMENT', `BINARY', `NULL', `UNSIGNED', and
          `ZEROFILL' data type attributes.

   * Functions and operators

        * To make it easier for users who migrate from other SQL
          environments, MySQL Server supports aliases for many
          functions. For example, all string functions support both
          standard SQL syntax and ODBC syntax.

        * MySQL Server understands the `||' and `&&' operators to mean
          logical OR and AND, as in the C programming language. In
          MySQL Server, `||' and `OR' are synonyms, as are `&&' and
          `AND'.  Because of this nice syntax, MySQL Server doesn't
          support the standard SQL `||' operator for string
          concatenation; use `CONCAT()' instead. Because `CONCAT()'
          takes any number of arguments, it is easy to convert use of
          the `||' operator to MySQL Server.

        * Use of `COUNT(DISTINCT VALUE_LIST)' where VALUE_LIST has more
          than one element.

        * String comparisons are case-insensitive by default, with sort
          ordering determined by the collation of the current character
          set, which is `latin1' (cp1252 West European) by default. If
          you don't like this, you should declare your columns with the
          `BINARY' attribute or use the `BINARY' cast, which causes
          comparisons to be done using the underlying character code
          values rather than a lexical ordering.

        * The `%' operator is a synonym for `MOD()'. That is, `N % M'
          is equivalent to `MOD(N,M)'.  `%' is supported for C
          programmers and for compatibility with PostgreSQL.

        * The `=', `<>', `<=', `<', `>=', `>', `<<', `>>', `<=>', `AND',
          `OR', or `LIKE' operators may be used in expressions in the
          output column list (to the left of the `FROM') in *Note
          `SELECT': select. statements. For example:

               mysql> SELECT col1=1 AND col2=2 FROM my_table;

        * The `LAST_INSERT_ID()' function returns the most recent
          `AUTO_INCREMENT' value. See *Note information-functions::.

        * `LIKE' is permitted on numeric values.

        * The `REGEXP' and `NOT REGEXP' extended regular expression
          operators.

        * `CONCAT()' or `CHAR()' with one argument or more than two
          arguments. (In MySQL Server, these functions can take a
          variable number of arguments.)

        * The `BIT_COUNT()', `CASE', `ELT()', `FROM_DAYS()', `FORMAT()',
          `IF()', `PASSWORD()', `ENCRYPT()', `MD5()', `ENCODE()',
          `DECODE()', `PERIOD_ADD()', `PERIOD_DIFF()', `TO_DAYS()', and
          `WEEKDAY()' functions.

        * Use of `TRIM()' to trim substrings. Standard SQL supports
          removal of single characters only.

        * The `GROUP BY' functions `STD()', `BIT_OR()', `BIT_AND()',
          `BIT_XOR()', and `GROUP_CONCAT()'. See *Note
          group-by-functions-and-modifiers::.


File: manual.info,  Node: differences-from-ansi,  Next: constraints,  Prev: extensions-to-ansi,  Up: compatibility

2.8.5 MySQL Differences from Standard SQL
-----------------------------------------

* Menu:

* ansi-diff-select-into-table::  `SELECT INTO TABLE'
* ansi-diff-update::             `UPDATE'
* ansi-diff-transactions::       Transactions and Atomic Operations
* ansi-diff-foreign-keys::       Foreign Keys
* ansi-diff-comments::           '`--'' as the Start of a Comment

We try to make MySQL Server follow the ANSI SQL standard and the ODBC
SQL standard, but MySQL Server performs operations differently in some
cases:

   * For *Note `VARCHAR': char. columns, trailing spaces are removed
     when the value is stored. (This is fixed in MySQL 5.0.3). See
     *Note bugs::.

   * In some cases, *Note `CHAR': char. columns are silently converted
     to *Note `VARCHAR': char. columns when you define a table or alter
     its structure. (This no longer occurs as of MySQL 5.0.3). See
     *Note silent-column-changes::.

   * There are several differences between the MySQL and standard SQL
     privilege systems. For example, in MySQL, privileges for a table
     are not automatically revoked when you delete a table. You must
     explicitly issue a *Note `REVOKE': revoke. statement to revoke
     privileges for a table. For more information, see *Note revoke::.

   * The `CAST()' function does not support cast to *Note `REAL':
     numeric-types. or *Note `BIGINT': numeric-types. See *Note
     cast-functions::.

   * Standard SQL requires that a `HAVING' clause in a *Note `SELECT':
     select. statement be able to refer to columns in the `GROUP BY'
     clause. This cannot be done before MySQL 5.0.2.


File: manual.info,  Node: ansi-diff-select-into-table,  Next: ansi-diff-update,  Prev: differences-from-ansi,  Up: differences-from-ansi

2.8.5.1 `SELECT INTO TABLE'
...........................

MySQL Server doesn't support the `SELECT ... INTO TABLE' Sybase SQL
extension. Instead, MySQL Server supports the *Note `INSERT INTO ...
SELECT': insert-select. standard SQL syntax, which is basically the
same thing. See *Note insert-select::. For example:

     INSERT INTO tbl_temp2 (fld_id)
         SELECT tbl_temp1.fld_order_id
         FROM tbl_temp1 WHERE tbl_temp1.fld_order_id > 100;

Alternatively, you can use *Note `SELECT ... INTO OUTFILE':
select-into. or *Note `CREATE TABLE ... SELECT': create-table.

You can use *Note `SELECT ... INTO': select. with user-defined
variables. The same syntax can also be used inside stored routines
using cursors and local variables. See *Note select-into::.


File: manual.info,  Node: ansi-diff-update,  Next: ansi-diff-transactions,  Prev: ansi-diff-select-into-table,  Up: differences-from-ansi

2.8.5.2 `UPDATE'
................

If you access a column from the table to be updated in an expression,
*Note `UPDATE': update. uses the current value of the column. The
second assignment in the following statement sets `col2' to the current
(updated) `col1' value, not the original `col1' value. The result is
that `col1' and `col2' have the same value. This behavior differs from
standard SQL.

     UPDATE t1 SET col1 = col1 + 1, col2 = col1;


File: manual.info,  Node: ansi-diff-transactions,  Next: ansi-diff-foreign-keys,  Prev: ansi-diff-update,  Up: differences-from-ansi

2.8.5.3 Transactions and Atomic Operations
..........................................

MySQL Server (version 3.23-max and all versions 4.0 and above) supports
transactions with the `InnoDB' and `BDB' transactional storage engines.
`InnoDB' provides _full_ ACID compliance. See *Note storage-engines::.
For information about `InnoDB' differences from standard SQL with
regard to treatment of transaction errors, see *Note
innodb-error-handling::.

The other nontransactional storage engines in MySQL Server (such as
`MyISAM') follow a different paradigm for data integrity called `atomic
operations.' In transactional terms, `MyISAM' tables effectively always
operate in `autocommit = 1' mode. Atomic operations often offer
comparable integrity with higher performance.

Because MySQL Server supports both paradigms, you can decide whether
your applications are best served by the speed of atomic operations or
the use of transactional features. This choice can be made on a
per-table basis.

As noted, the tradeoff for transactional versus nontransactional
storage engines lies mostly in performance.  Transactional tables have
significantly higher memory and disk space requirements, and more CPU
overhead. On the other hand, transactional storage engines such as
`InnoDB' also offer many significant features. MySQL Server's modular
design enables the concurrent use of different storage engines to suit
different requirements and deliver optimum performance in all
situations.

But how do you use the features of MySQL Server to maintain rigorous
integrity even with the nontransactional `MyISAM' tables, and how do
these features compare with the transactional storage engines?

   * If your applications are written in a way that is dependent on
     being able to call *Note `ROLLBACK': commit.  rather than *Note
     `COMMIT': commit. in critical situations, transactions are more
     convenient.  Transactions also ensure that unfinished updates or
     corrupting activities are not committed to the database; the
     server is given the opportunity to do an automatic rollback and
     your database is saved.

     If you use nontransactional tables, MySQL Server in almost all
     cases enables you to resolve potential problems by including
     simple checks before updates and by running simple scripts that
     check the databases for inconsistencies and automatically repair
     or warn if such an inconsistency occurs. You can normally fix
     tables perfectly with no data integrity loss just by using the
     MySQL log or even adding one extra log.

   * More often than not, critical transactional updates can be
     rewritten to be atomic. Generally speaking, all integrity problems
     that transactions solve can be done with *Note `LOCK TABLES':
     lock-tables. or atomic updates, ensuring that there are no
     automatic aborts from the server, which is a common problem with
     transactional database systems.

   * To be safe with MySQL Server, regardless of whether you use
     transactional tables, you only need to have backups and have
     binary logging turned on. When that is true, you can recover from
     any situation that you could with any other transactional database
     system. It is always good to have backups, regardless of which
     database system you use.

The transactional paradigm has its advantages and disadvantages. Many
users and application developers depend on the ease with which they can
code around problems where an abort appears to be necessary, or is
necessary. However, even if you are new to the atomic operations
paradigm, or more familiar with transactions, do consider the speed
benefit that nontransactional tables can offer on the order of three to
five times the speed of the fastest and most optimally tuned
transactional tables.

In situations where integrity is of highest importance, MySQL Server
offers transaction-level reliability and integrity even for
nontransactional tables. If you lock tables with *Note `LOCK TABLES':
lock-tables, all updates stall until integrity checks are made. If you
obtain a `READ LOCAL' lock (as opposed to a write lock) for a table
that enables concurrent inserts at the end of the table, reads are
permitted, as are inserts by other clients. The newly inserted records
are not be seen by the client that has the read lock until it releases
the lock. With *Note `INSERT DELAYED': insert-delayed, you can write
inserts that go into a local queue until the locks are released,
without having the client wait for the insert to complete. See *Note
concurrent-inserts::, and *Note insert-delayed::.

`Atomic,' in the sense that we mean it, is nothing magical. It only
means that you can be sure that while each specific update is running,
no other user can interfere with it, and there can never be an
automatic rollback (which can happen with transactional tables if you
are not very careful). MySQL Server also guarantees that there are no
dirty reads.

Following are some techniques for working with nontransactional tables:

   * Loops that need transactions normally can be coded with the help
     of *Note `LOCK TABLES': lock-tables, and you don't need cursors to
     update records on the fly.

   * To avoid using *Note `ROLLBACK': commit, you can employ the
     following strategy:

       1. Use *Note `LOCK TABLES': lock-tables. to lock all the tables
          you want to access.

       2. Test the conditions that must be true before performing the
          update.

       3. Update if the conditions are satisfied.

       4. Use *Note `UNLOCK TABLES': lock-tables. to release your locks.

     This is usually a much faster method than using transactions with
     possible rollbacks, although not always.  The only situation this
     solution doesn't handle is when someone kills the threads in the
     middle of an update. In that case, all locks are released but some
     of the updates may not have been executed.

   * You can also use functions to update records in a single
     operation. You can get a very efficient application by using the
     following techniques:

        * Modify columns relative to their current value.

        * Update only those columns that actually have changed.

     For example, when we are updating customer information, we update
     only the customer data that has changed and test only that none of
     the changed data, or data that depends on the changed data, has
     changed compared to the original row. The test for changed data is
     done with the `WHERE' clause in the *Note `UPDATE': update.
     statement. If the record wasn't updated, we give the client a
     message: `Some of the data you have changed has been changed by
     another user.' Then we show the old row versus the new row in a
     window so that the user can decide which version of the customer
     record to use.

     This gives us something that is similar to column locking but is
     actually even better because we only update some of the columns,
     using values that are relative to their current values. This means
     that typical *Note `UPDATE': update. statements look something
     like these:

          UPDATE tablename SET pay_back=pay_back+125;

          UPDATE customer
            SET
              customer_date='current_date',
              address='new address',
              phone='new phone',
              money_owed_to_us=money_owed_to_us-125
            WHERE
              customer_id=id AND address='old address' AND phone='old phone';

     This is very efficient and works even if another client has
     changed the values in the `pay_back' or `money_owed_to_us' columns.

   * In many cases, users have wanted *Note `LOCK TABLES': lock-tables.
     or *Note `ROLLBACK': commit.  for the purpose of managing unique
     identifiers. This can be handled much more efficiently without
     locking or rolling back by using an `AUTO_INCREMENT' column and
     either the `LAST_INSERT_ID()' SQL function or the *Note
     `mysql_insert_id()': mysql-insert-id. C API function. See *Note
     information-functions::, and *Note mysql-insert-id::.

     You can generally code around the need for row-level locking. Some
     situations really do need it, and `InnoDB' tables support row-level
     locking. Otherwise, with `MyISAM' tables, you can use a flag
     column in the table and do something like the following:

          UPDATE TBL_NAME SET row_flag=1 WHERE id=ID;

     MySQL returns `1' for the number of affected rows if the row was
     found and `row_flag' wasn't `1' in the original row. You can think
     of this as though MySQL Server changed the preceding statement to:

          UPDATE TBL_NAME SET row_flag=1 WHERE id=ID AND row_flag <> 1;


File: manual.info,  Node: ansi-diff-foreign-keys,  Next: ansi-diff-comments,  Prev: ansi-diff-transactions,  Up: differences-from-ansi

2.8.5.4 Foreign Keys
....................

The `InnoDB' storage engine supports checking of foreign key
constraints, including `CASCADE', `ON DELETE', and `ON UPDATE'. See
*Note innodb-foreign-key-constraints::.

For storage engines other than `InnoDB', MySQL Server parses the
`FOREIGN KEY' syntax in *Note `CREATE TABLE': create-table. statements,
but does not use or store it. In the future, the implementation will be
extended to store this information in the table specification file so
that it may be retrieved by *Note `mysqldump': mysqldump. and ODBC. At
a later stage, foreign key constraints will be implemented for `MyISAM'
tables as well.

Foreign key enforcement offers several benefits to database developers:

   * Assuming proper design of the relationships, foreign key
     constraints make it more difficult for a programmer to introduce
     an inconsistency into the database.

   * Centralized checking of constraints by the database server makes
     it unnecessary to perform these checks on the application side.
     This eliminates the possibility that different applications may
     not all check the constraints in the same way.

   * Using cascading updates and deletes can simplify the application
     code.

   * Properly designed foreign key rules aid in documenting
     relationships between tables.

Do keep in mind that these benefits come at the cost of additional
overhead for the database server to perform the necessary checks.
Additional checking by the server affects performance, which for some
applications may be sufficiently undesirable as to be avoided if
possible. (Some major commercial applications have coded the foreign
key logic at the application level for this reason.)

MySQL gives database developers the choice of which approach to use. If
you don't need foreign keys and want to avoid the overhead associated
with enforcing referential integrity, you can choose another storage
engine instead, such as `MyISAM'. (For example, the `MyISAM' storage
engine offers very fast performance for applications that perform only
*Note `INSERT': insert. and *Note `SELECT': select. operations. In this
case, the table has no holes in the middle and the inserts can be
performed concurrently with retrievals. See *Note concurrent-inserts::.)

If you choose not to take advantage of referential integrity checks,
keep the following considerations in mind:

   * In the absence of server-side foreign key relationship checking,
     the application itself must handle relationship issues. For
     example, it must take care to insert rows into tables in the
     proper order, and to avoid creating orphaned child records. It
     must also be able to recover from errors that occur in the middle
     of multiple-record insert operations.

   * If `ON DELETE' is the only referential integrity capability an
     application needs, you can achieve a similar effect as of MySQL
     Server 4.0 by using multiple-table *Note `DELETE': delete.
     statements to delete rows from many tables with a single
     statement. See *Note delete::.

   * A workaround for the lack of `ON DELETE' is to add the appropriate
     *Note `DELETE': delete. statements to your application when you
     delete records from a table that has a foreign key. In practice,
     this is often as quick as using foreign keys and is more portable.

Be aware that the use of foreign keys can sometimes lead to problems:

   * Foreign key support addresses many referential integrity issues,
     but it is still necessary to design key relationships carefully to
     avoid circular rules or incorrect combinations of cascading
     deletes.

   * It is not uncommon for a DBA to create a topology of relationships
     that makes it difficult to restore individual tables from a
     backup. (MySQL alleviates this difficulty by enabling you to
     temporarily disable foreign key checks when reloading a table that
     depends on other tables. See *Note
     innodb-foreign-key-constraints::. As of MySQL 4.1.1, *Note
     `mysqldump': mysqldump. generates dump files that take advantage
     of this capability automatically when they are reloaded.)

Foreign keys in SQL are used to check and enforce referential
integrity, not to join tables. If you want to get results from multiple
tables from a *Note `SELECT': select.  statement, you do this by
performing a join between them:

     SELECT * FROM t1 INNER JOIN t2 ON t1.id = t2.id;

See *Note join::, and *Note example-foreign-keys::.

The `FOREIGN KEY' syntax without `ON DELETE ...' is often used by ODBC
applications to produce automatic `WHERE' clauses.


File: manual.info,  Node: ansi-diff-comments,  Prev: ansi-diff-foreign-keys,  Up: differences-from-ansi

2.8.5.5 '`--'' as the Start of a Comment
........................................

Standard SQL uses the C syntax `/* this is a comment */' for comments,
and MySQL Server supports this syntax as well. MySQL also support
extensions to this syntax that enable MySQL-specific SQL to be embedded
in the comment, as described in *Note comments::.

Standard SQL uses ``--'' as a start-comment sequence. MySQL Server uses
``#'' as the start comment character. MySQL Server 3.23.3 and up also
supports a variant of the ``--'' comment style.  That is, the ``--''
start-comment sequence must be followed by a space (or by a control
character such as a newline). The space is required to prevent problems
with automatically generated SQL queries that use constructs such as
the following, where we automatically insert the value of the payment
for `payment':

     UPDATE account SET credit=credit-payment

Consider about what happens if `payment' has a negative value such as
`-1':

     UPDATE account SET credit=credit--1

`credit--1' is a legal expression in SQL, but ``--'' is interpreted as
the start of a comment, part of the expression is discarded. The result
is a statement that has a completely different meaning than intended:

     UPDATE account SET credit=credit

The statement produces no change in value at all. This illustrates that
permitting comments to start with ``--'' can have serious consequences.

Using our implementation requires a space following the ``--'' for it
to be recognized as a start-comment sequence in MySQL Server 3.23.3 and
newer.  Therefore, `credit--1' is safe to use.

Another safe feature is that the *Note `mysql': mysql.  command-line
client ignores lines that start with ``--''.

The following information is relevant only if you are running a MySQL
version earlier than 3.23.3:

If you have an SQL script in a text file that contains ``--'' comments,
you should use the *Note `replace': replace-utility. utility as follows
to convert the comments to use ``#'' characters before executing the
script:

     shell> replace " --" " #" < text-file-with-funny-comments.sql \
              | mysql DB_NAME

That is safer than executing the script in the usual way:

     shell> mysql DB_NAME < text-file-with-funny-comments.sql

You can also edit the script file `in place' to change the ``--''
comments to ``#'' comments:

     shell> replace " --" " #" -- text-file-with-funny-comments.sql

Change them back with this command:

     shell> replace " #" " --" -- text-file-with-funny-comments.sql

See *Note replace-utility::.


File: manual.info,  Node: constraints,  Prev: differences-from-ansi,  Up: compatibility

2.8.6 How MySQL Deals with Constraints
--------------------------------------

* Menu:

* constraint-primary-key::       `PRIMARY KEY' and `UNIQUE' Index Constraints
* constraint-invalid-data::      Constraints on Invalid Data
* constraint-enum::              `ENUM' and `SET' Constraints

MySQL enables you to work both with transactional tables that permit
rollback and with nontransactional tables that do not.  Because of
this, constraint handling is a bit different in MySQL than in other
DBMSs. We must handle the case when you have inserted or updated a lot
of rows in a nontransactional table for which changes cannot be rolled
back when an error occurs.

The basic philosophy is that MySQL Server tries to produce an error for
anything that it can detect while parsing a statement to be executed,
and tries to recover from any errors that occur while executing the
statement. We do this in most cases, but not yet for all.

The options MySQL has when an error occurs are to stop the statement in
the middle or to recover as well as possible from the problem and
continue. By default, the server follows the latter course. This means,
for example, that the server may coerce illegal values to the closest
legal values.

Beginning with MySQL 5.0.2, several SQL mode options are available to
provide greater control over handling of bad data values and whether to
continue statement execution or abort when errors occur. Using these
options, you can configure MySQL Server to act in a more traditional
fashion that is like other DBMSs that reject improper input. The SQL
mode can be set globally at server startup to affect all clients.
Individual clients can set the SQL mode at runtime, which enables each
client to select the behavior most appropriate for its requirements.
See *Note server-sql-mode::.

The following sections describe how MySQL Server handles different
types of constraints.


File: manual.info,  Node: constraint-primary-key,  Next: constraint-invalid-data,  Prev: constraints,  Up: constraints

2.8.6.1 `PRIMARY KEY' and `UNIQUE' Index Constraints
....................................................

Normally, errors occurs for data-change statements (such as *Note
`INSERT': insert. or *Note `UPDATE': update.) that would violate
primary-key, unique-key, or foreign-key constraints. If you are using a
transactional storage engine such as `InnoDB', MySQL automatically
rolls back the statement. If you are using a nontransactional storage
engine, MySQL stops processing the statement at the row for which the
error occurred and leaves any remaining rows unprocessed.

MySQL supports an `IGNORE' keyword for *Note `INSERT': insert, *Note
`UPDATE': update, and so forth. If you use it, MySQL ignores
primary-key or unique-key violations and continues processing with the
next row. See the section for the statement that you are using (*Note
insert::, *Note update::, and so forth).

You can get information about the number of rows actually inserted or
updated with the *Note `mysql_info()': mysql-info. C API function.  You
can also use the *Note `SHOW WARNINGS': show-warnings. statement. See
*Note mysql-info::, and *Note show-warnings::.

Currently, only `InnoDB' tables support foreign keys. See *Note
innodb-foreign-key-constraints::.


File: manual.info,  Node: constraint-invalid-data,  Next: constraint-enum,  Prev: constraint-primary-key,  Up: constraints

2.8.6.2 Constraints on Invalid Data
...................................

Before MySQL 5.0.2, MySQL is forgiving of illegal or improper data
values and coerces them to legal values for data entry.  In MySQL 5.0.2
and up, that remains the default behavior, but you can change the
server SQL mode to select more traditional treatment of bad values such
that the server rejects them and aborts the statement in which they
occur.  *Note server-sql-mode::.

This section describes the default (forgiving) behavior of MySQL, as
well as the strict SQL mode and how it differs.

If you are not using strict mode, then whenever you insert an
`incorrect' value into a column, such as a `NULL' into a `NOT NULL'
column or a too-large numeric value into a numeric column, MySQL sets
the column to the `best possible value' instead of producing an error:
The following rules describe in more detail how this works:

   * If you try to store an out of range value into a numeric column,
     MySQL Server instead stores zero, the smallest possible value, or
     the largest possible value, whichever is closest to the invalid
     value.

   * For strings, MySQL stores either the empty string or as much of
     the string as can be stored in the column.

   * If you try to store a string that doesn't start with a number into
     a numeric column, MySQL Server stores 0.

   * Invalid values for *Note `ENUM': enum. and *Note `SET': set.
     columns are handled as described in *Note constraint-enum::.

   * MySQL enables you to store certain incorrect date values into
     *Note `DATE': datetime. and *Note `DATETIME': datetime. columns
     (such as `'2000-02-31'' or `'2000-02-00''). The idea is that it is
     not the job of the SQL server to validate dates. If MySQL can
     store a date value and retrieve exactly the same value, MySQL
     stores it as given. If the date is totally wrong (outside the
     server's ability to store it), the special `zero' date value
     `'0000-00-00'' is stored in the column instead.

   * If you try to store `NULL' into a column that doesn't take `NULL'
     values, an error occurs for single-row *Note `INSERT': insert.
     statements. For multiple-row *Note `INSERT': insert.  statements
     or for *Note `INSERT INTO ... SELECT': insert-select. statements,
     MySQL Server stores the implicit default value for the column data
     type. In general, this is `0' for numeric types, the empty string
     (`''') for string types, and the `zero' value for date and time
     types.  Implicit default values are discussed in *Note
     data-type-defaults::.

   * If an *Note `INSERT': insert. statement specifies no value for a
     column, MySQL inserts its default value if the column definition
     includes an explicit `DEFAULT' clause. If the definition has no
     such `DEFAULT' clause, MySQL inserts the implicit default value
     for the column data type.

The reason for using the preceding rules in nonstrict mode is that we
can't check these conditions until the statement has begun executing.
We can't just roll back if we encounter a problem after updating a few
rows, because the storage engine may not support rollback. The option
of terminating the statement is not that good; in this case, the update
would be `half done,' which is probably the worst possible scenario. In
this case, it is better to `do the best you can' and then continue as
if nothing happened.

In MySQL 5.0.2 and up, you can select stricter treatment of input
values by using the `STRICT_TRANS_TABLES' or `STRICT_ALL_TABLES' SQL
modes:

     SET sql_mode = 'STRICT_TRANS_TABLES';
     SET sql_mode = 'STRICT_ALL_TABLES';

`STRICT_TRANS_TABLES' enables strict mode for transactional storage
engines, and also to some extent for nontransactional engines. It works
like this:

   * For transactional storage engines, bad data values occurring
     anywhere in a statement cause the statement to abort and roll back.

   * For nontransactional storage engines, a statement aborts if the
     error occurs in the first row to be inserted or updated. (When the
     error occurs in the first row, the statement can be aborted to
     leave the table unchanged, just as for a transactional table.)
     Errors in rows after the first do not abort the statement, because
     the table has already been changed by the first row. Instead, bad
     data values are adjusted and result in warnings rather than
     errors. In other words, with `STRICT_TRANS_TABLES', a wrong value
     causes MySQL to roll back all updates done so far, if that can be
     done without changing the table. But once the table has been
     changed, further errors result in adjustments and warnings.

For even stricter checking, enable `STRICT_ALL_TABLES'. This is the
same as `STRICT_TRANS_TABLES' except that for nontransactional storage
engines, errors abort the statement even for bad data in rows following
the first row.  This means that if an error occurs partway through a
multiple-row insert or update for a nontransactional table, a partial
update results. Earlier rows are inserted or updated, but those from
the point of the error on are not. To avoid this for nontransactional
tables, either use single-row statements or else use
`STRICT_TRANS_TABLES' if conversion warnings rather than errors are
acceptable. To avoid problems in the first place, do not use MySQL to
check column content. It is safest (and often faster) to let the
application ensure that it passes only legal values to the database.

With either of the strict mode options, you can cause errors to be
treated as warnings by using *Note `INSERT IGNORE': insert. or `UPDATE
IGNORE' rather than *Note `INSERT': insert. or *Note `UPDATE': update.
without `IGNORE'.


File: manual.info,  Node: constraint-enum,  Prev: constraint-invalid-data,  Up: constraints

2.8.6.3 `ENUM' and `SET' Constraints
....................................

*Note `ENUM': enum. and *Note `SET': set. columns provide an efficient
way to define columns that can contain only a given set of values. See
*Note enum::, and *Note set::. However, before MySQL 5.0.2, *Note
`ENUM': enum. and *Note `SET': set. columns do not provide true
constraints on entry of invalid data:

   * *Note `ENUM': enum. columns always have a default value. If you
     specify no default value, then it is `NULL' for columns that can
     have `NULL', otherwise it is the first enumeration value in the
     column definition.

   * If you insert an incorrect value into an *Note `ENUM': enum.
     column or if you force a value into an *Note `ENUM': enum. column
     with `IGNORE', it is set to the reserved enumeration value of `0',
     which is displayed as an empty string in string context.

   * If you insert an incorrect value into a *Note `SET': set. column,
     the incorrect value is ignored. For example, if the column can
     contain the values `'a'', `'b'', and `'c'', an attempt to assign
     `'a,x,b,y'' results in a value of `'a,b''.

As of MySQL 5.0.2, you can configure the server to use strict SQL mode.
See *Note server-sql-mode::. With strict mode enabled, the definition
of a *Note `ENUM': enum. or *Note `SET': set. column does act as a
constraint on values entered into the column. An error occurs for
values that do not satisfy these conditions:

   * An *Note `ENUM': enum. value must be one of those listed in the
     column definition, or the internal numeric equivalent thereof. The
     value cannot be the error value (that is, 0 or the empty string).
     For a column defined as *Note `ENUM('a','b','c')': enum, values
     such as `''', `'d'', or `'ax'' are illegal and are rejected.

   * A *Note `SET': set. value must be the empty string or a value
     consisting only of the values listed in the column definition
     separated by commas. For a column defined as *Note
     `SET('a','b','c')': set, values such as `'d'' or `'a,b,c,d'' are
     illegal and are rejected.

Errors for invalid values can be suppressed in strict mode if you use
*Note `INSERT IGNORE': insert. or `UPDATE IGNORE'. In this case, a
warning is generated rather than an error. For *Note `ENUM': enum, the
value is inserted as the error member (`0'). For *Note `SET': set, the
value is inserted as given except that any invalid substrings are
deleted. For example, `'a,x,b,y'' results in a value of `'a,b''.


File: manual.info,  Node: credits,  Prev: compatibility,  Up: introduction

2.9 Credits
===========

* Menu:

* contributors::                 Contributors to MySQL
* documenters-translators::      Documenters and translators
* packages::                     Packages that support MySQL
* tools-used-to-create-mysql::   Tools that were used to create MySQL
* supporters::                   Supporters of MySQL

The following sections list developers, contributors, and supporters
that have helped to make MySQL what it is today.


File: manual.info,  Node: contributors,  Next: documenters-translators,  Prev: credits,  Up: credits

2.9.1 Contributors to MySQL
---------------------------

Although Oracle Corporation and/or its affiliates own all copyrights in
the `MySQL server' and the `MySQL manual', we wish to recognize those
who have made contributions of one kind or another to the `MySQL
distribution'. Contributors are listed here, in somewhat random order:

   * Gianmassimo Vigazzola <qwerg@mbox.vol.it> or <qwerg@tin.it>

     The initial port to Win32/NT.

   * Per Eric Olsson

     For constructive criticism and real testing of the dynamic record
     format.

   * Irena Pancirov <irena@mail.yacc.it>

     Win32 port with Borland compiler.  `mysqlshutdown.exe' and
     `mysqlwatch.exe'.

   * David J. Hughes

     For the effort to make a shareware SQL database. At TcX, the
     predecessor of MySQL AB, we started with `mSQL', but found that it
     couldn't satisfy our purposes so instead we wrote an SQL interface
     to our application builder Unireg. *Note `mysqladmin': mysqladmin.
     and *Note `mysql': mysql. client are programs that were largely
     influenced by their `mSQL' counterparts. We have put a lot of
     effort into making the MySQL syntax a superset of `mSQL'. Many of
     the API's ideas are borrowed from `mSQL' to make it easy to port
     free `mSQL' programs to the MySQL API.  The MySQL software doesn't
     contain any code from `mSQL'. Two files in the distribution
     (`client/insert_test.c' and `client/select_test.c') are based on
     the corresponding (noncopyrighted) files in the `mSQL'
     distribution, but are modified as examples showing the changes
     necessary to convert code from `mSQL' to MySQL Server.  (`mSQL' is
     copyrighted David J. Hughes.)

   * Patrick Lynch

     For helping us acquire http://www.mysql.com/.

   * Fred Lindberg

     For setting up qmail to handle the MySQL mailing list and for the
     incredible help we got in managing the MySQL mailing lists.

   * Igor Romanenko <igor@frog.kiev.ua>

     *Note `mysqldump': mysqldump. (previously `msqldump', but ported
     and enhanced by Monty).

   * Yuri Dario

     For keeping up and extending the MySQL OS/2 port.

   * Tim Bunce

     Author of *Note `mysqlhotcopy': mysqlhotcopy.

   * Zarko Mocnik <zarko.mocnik@dem.si>

     Sorting for Slovenian language.

   * "TAMITO" <tommy@valley.ne.jp>

     The `_MB' character set macros and the ujis and sjis character
     sets.

   * Joshua Chamas <joshua@chamas.com>

     Base for concurrent insert, extended date syntax, debugging on NT,
     and answering on the MySQL mailing list.

   * Yves Carlier <Yves.Carlier@rug.ac.be>

     *Note `mysqlaccess': mysqlaccess, a program to show the access
     rights for a user.

   * Rhys Jones <rhys@wales.com> (And GWE Technologies Limited)

     For one of the early JDBC drivers.

   * Dr Xiaokun Kelvin ZHU <X.Zhu@brad.ac.uk>

     Further development of one of the early JDBC drivers and other
     MySQL-related Java tools.

   * James Cooper <pixel@organic.com>

     For setting up a searchable mailing list archive at his site.

   * Rick Mehalick <Rick_Mehalick@i-o.com>

     For `xmysql', a graphical X client for MySQL Server.

   * Doug Sisk <sisk@wix.com>

     For providing RPM packages of MySQL for Red Hat Linux.

   * Diemand Alexander V. <axeld@vial.ethz.ch>

     For providing RPM packages of MySQL for Red Hat Linux-Alpha.

   * Antoni Pamies Olive <toni@readysoft.es>

     For providing RPM versions of a lot of MySQL clients for Intel and
     SPARC.

   * Jay Bloodworth <jay@pathways.sde.state.sc.us>

     For providing RPM versions for MySQL 3.21.

   * David Sacerdote <davids@secnet.com>

     Ideas for secure checking of DNS host names.

   * Wei-Jou Chen <jou@nematic.ieo.nctu.edu.tw>

     Some support for Chinese(BIG5) characters.

   * Wei He <hewei@mail.ied.ac.cn>

     A lot of functionality for the Chinese(GBK) character set.

   * Jan Pazdziora <adelton@fi.muni.cz>

     Czech sorting order.

   * Zeev Suraski <bourbon@netvision.net.il>

     `FROM_UNIXTIME()' time formatting, `ENCRYPT()' functions, and
     `bison' advisor. Active mailing list member.

   * Luuk de Boer <luuk@wxs.nl>

     Ported (and extended) the benchmark suite to `DBI'/`DBD'. Have
     been of great help with `crash-me' and running benchmarks. Some
     new date functions. The *Note `mysql_setpermission':
     mysql-setpermission. script.

   * Alexis Mikhailov <root@medinf.chuvashia.su>

     User-defined functions (UDFs); *Note `CREATE FUNCTION':
     create-function. and *Note `DROP FUNCTION': drop-function.

   * Andreas F. Bobak <bobak@relog.ch>

     The `AGGREGATE' extension to user-defined functions.

   * Ross Wakelin <R.Wakelin@march.co.uk>

     Help to set up InstallShield for MySQL-Win32.

   * Jethro Wright III <jetman@li.net>

     The `libmysql.dll' library.

   * James Pereria <jpereira@iafrica.com>

     Mysqlmanager, a Win32 GUI tool for administering MySQL Servers.

   * Curt Sampson <cjs@portal.ca>

     Porting of MIT-pthreads to NetBSD/Alpha and NetBSD 1.3/i386.

   * Martin Ramsch <m.ramsch@computer.org>

     Examples in the MySQL Tutorial.

   * Steve Harvey

     For making *Note `mysqlaccess': mysqlaccess. more secure.

   * Konark IA-64 Centre of Persistent Systems Private Limited

     `http://www.pspl.co.in/konark/'. Help with the Win64 port of the
     MySQL server.

   * Albert Chin-A-Young.

     Configure updates for Tru64, large file support and better TCP
     wrappers support.

   * John Birrell

     Emulation of `pthread_mutex()' for OS/2.

   * Benjamin Pflugmann

     Extended `MERGE' tables to handle `INSERTS'. Active member on the
     MySQL mailing lists.

   * Jocelyn Fournier

     Excellent spotting and reporting innumerable bugs (especially in
     the MySQL 4.1 subquery code).

   * Marc Liyanage

     Maintaining the Mac OS X packages and providing invaluable
     feedback on how to create Mac OS X packages.

   * Robert Rutherford

     Providing invaluable information and feedback about the QNX port.

   * Previous developers of NDB Cluster

     Lots of people were involved in various ways summer students,
     master thesis students, employees. In total more than 100 people
     so too many to mention here. Notable name is Ataullah Dabaghi who
     up until 1999 contributed around a third of the code base. A
     special thanks also to developers of the AXE system which provided
     much of the architectural foundations for NDB Cluster with blocks,
     signals and crash tracing functionality. Also credit should be
     given to those who believed in the ideas enough to allocate of
     their budgets for its development from 1992 to present time.

   * Google Inc.

     We wish to recognize Google Inc. for contributions to the MySQL
     distribution: Mark Callaghan's SMP Performance patches and other
     patches.

Other contributors, bugfinders, and testers: James H. Thompson,
Maurizio Menghini, Wojciech Tryc, Luca Berra, Zarko Mocnik, Wim Bonis,
Elmar Haneke, <jehamby@lightside>, <psmith@BayNetworks.com>,
<duane@connect.com.au>, Ted Deppner <ted@psyber.com>, Mike Simons,
Jaakko Hyvatti.

And lots of bug report/patches from the folks on the mailing list.

A big tribute goes to those that help us answer questions on the MySQL
mailing lists:

   * Daniel Koch <dkoch@amcity.com>

     Irix setup.

   * Luuk de Boer <luuk@wxs.nl>

     Benchmark questions.

   * Tim Sailer <tps@users.buoy.com>

     `DBD::mysql' questions.

   * Boyd Lynn Gerber <gerberb@zenez.com>

     SCO-related questions.

   * Richard Mehalick <RM186061@shellus.com>

     `xmysql'-related questions and basic installation questions.

   * Zeev Suraski <bourbon@netvision.net.il>

     Apache module configuration questions (log & auth), PHP-related
     questions, SQL syntax-related questions and other general
     questions.

   * Francesc Guasch <frankie@citel.upc.es>

     General questions.

   * Jonathan J Smith <jsmith@wtp.net>

     Questions pertaining to OS-specifics with Linux, SQL syntax, and
     other things that might need some work.

   * David Sklar <sklar@student.net>

     Using MySQL from PHP and Perl.

   * Alistair MacDonald <A.MacDonald@uel.ac.uk>

     Is flexible and can handle Linux and perhaps HP-UX.

   * John Lyon <jlyon@imag.net>

     Questions about installing MySQL on Linux systems, using either
     `.rpm' files or compiling from source.

   * Lorvid Ltd. <lorvid@WOLFENET.com>

     Simple billing/license/support/copyright issues.

   * Patrick Sherrill <patrick@coconet.com>

     ODBC and VisualC++ interface questions.

   * Randy Harmon <rjharmon@uptimecomputers.com>

     `DBD', Linux, some SQL syntax questions.


File: manual.info,  Node: documenters-translators,  Next: packages,  Prev: contributors,  Up: credits

2.9.2 Documenters and translators
---------------------------------

The following people have helped us with writing the MySQL
documentation and translating the documentation or error messages in
MySQL.

   * Paul DuBois

     Ongoing help with making this manual correct and understandable.
     That includes rewriting Monty's and David's attempts at English
     into English as other people know it.

   * Kim Aldale

     Helped to rewrite Monty's and David's early attempts at English
     into English.

   * Michael J. Miller Jr.  <mke@terrapin.turbolift.com>

     For the first MySQL manual. And a lot of spelling/language fixes
     for the FAQ (that turned into the MySQL manual a long time ago).

   * Yan Cailin

     First translator of the MySQL Reference Manual into simplified
     Chinese in early 2000 on which the Big5 and HK coded
     (`http://mysql.hitstar.com/') versions were based. Personal home
     page at linuxdb.yeah.net (http://linuxdb.yeah.net).

   * Jay Flaherty <fty@mediapulse.com>

     Big parts of the Perl `DBI'/`DBD' section in the manual.

   * Paul Southworth <pauls@etext.org>, Ray Loyzaga <yar@cs.su.oz.au>

     Proof-reading of the Reference Manual.

   * Therrien Gilbert <gilbert@ican.net>, Jean-Marc Pouyot
     <jmp@scalaire.fr>

     French error messages.

   * Petr Snajdr, <snajdr@pvt.net>

     Czech error messages.

   * Jaroslaw Lewandowski <jotel@itnet.com.pl>

     Polish error messages.

   * Miguel Angel Fernandez Roiz

     Spanish error messages.

   * Roy-Magne Mo <rmo@www.hivolda.no>

     Norwegian error messages and testing of MySQL 3.21.xx.

   * Timur I. Bakeyev <root@timur.tatarstan.ru>

     Russian error messages.

   * <brenno@dewinter.com> & Filippo Grassilli <phil@hyppo.com>

     Italian error messages.

   * Dirk Munzinger <dirk@trinity.saar.de>

     German error messages.

   * Billik Stefan <billik@sun.uniag.sk>

     Slovak error messages.

   * Stefan Saroiu <tzoompy@cs.washington.edu>

     Romanian error messages.

   * Peter Feher

     Hungarian error messages.

   * Roberto M. Serqueira

     Portuguese error messages.

   * Carsten H. Pedersen

     Danish error messages.

   * Arjen Lentz

     Dutch error messages, completing earlier partial translation (also
     work on consistency and spelling).


File: manual.info,  Node: packages,  Next: tools-used-to-create-mysql,  Prev: documenters-translators,  Up: credits

2.9.3 Packages that support MySQL
---------------------------------

The following is a list of creators/maintainers of some of the most
important API/packages/applications that a lot of people use with MySQL.

We cannot list every possible package here because the list would then
be way to hard to maintain. For other packages, please refer to the
software portal at `http://solutions.mysql.com/software/'.

   * Tim Bunce, Alligator Descartes

     For the `DBD' (Perl) interface.

   * Andreas Koenig <a.koenig@mind.de>

     For the Perl interface for MySQL Server.

   * Jochen Wiedmann <wiedmann@neckar-alb.de>

     For maintaining the Perl `DBD::mysql' module.

   * Eugene Chan <eugene@acenet.com.sg>

     For porting PHP for MySQL Server.

   * Georg Richter

     MySQL 4.1 testing and bug hunting. New PHP 5.0 `mysqli' extension
     (API) for use with MySQL 4.1 and up.

   * Giovanni Maruzzelli <maruzz@matrice.it>

     For porting iODBC (Unix ODBC).

   * Xavier Leroy <Xavier.Leroy@inria.fr>

     The author of LinuxThreads (used by the MySQL Server on Linux).


File: manual.info,  Node: tools-used-to-create-mysql,  Next: supporters,  Prev: packages,  Up: credits

2.9.4 Tools that were used to create MySQL
------------------------------------------

The following is a list of some of the tools we have used to create
MySQL. We use this to express our thanks to those that has created them
as without these we could not have made MySQL what it is today.

   * Free Software Foundation

     From whom we got an excellent compiler (`gcc'), an excellent
     debugger (`gdb' and the `libc' library (from which we have borrowed
     `strto.c' to get some code working in Linux).

   * Free Software Foundation & The XEmacs development team

     For a really great editor/environment.

   * Julian Seward

     Author of `valgrind', an excellent memory checker tool that has
     helped us find a lot of otherwise hard to find bugs in MySQL.

   * Dorothea Lu"tkehaus and Andreas Zeller

     For `DDD' (The Data Display Debugger) which is an excellent
     graphical front end to `gdb').


File: manual.info,  Node: supporters,  Prev: tools-used-to-create-mysql,  Up: credits

2.9.5 Supporters of MySQL
-------------------------

Although Oracle Corporation and/or its affiliates own all copyrights in
the `MySQL server' and the `MySQL manual', we wish to recognize the
following companies, which helped us finance the development of the
`MySQL server', such as by paying us for developing a new feature or
giving us hardware for development of the `MySQL server'.

   * VA Linux / Andover.net

     Funded replication.

   * NuSphere

     Editing of the MySQL manual.

   * Stork Design studio

     The MySQL Web site in use between 1998-2000.

   * Intel

     Contributed to development on Windows and Linux platforms.

   * Compaq

     Contributed to Development on Linux/Alpha.

   * SWSoft

     Development on the embedded *Note `mysqld': mysqld. version.

   * FutureQuest

     The `--skip-show-database' option.


File: manual.info,  Node: installing,  Next: tutorial,  Prev: introduction,  Up: Top

3 Installing and Upgrading MySQL
********************************

* Menu:

* installation-overview::        MySQL Installation Overview
* installation-version::         Determining your current MySQL version
* installing-es::                Notes for MySQL Enterprise Server
* installing-cs::                Notes for MySQL Community Server
* getting-mysql::                How to Get MySQL
* verifying-package-integrity::  Verifying Package Integrity Using MD5 Checksums or `GnuPG'
* installation-layouts::         Installation Layouts
* compiler-characteristics::     Compiler-Specific Build Characteristics
* quick-standard-installation::  Standard MySQL Installation from a Binary Distribution
* windows-installation::         Installing MySQL on Microsoft Windows
* macosx-installation::          Installing MySQL on Mac OS X
* linux-installation-rpm::       Installing MySQL from RPM Packages on Linux
* solaris-installation::         Installing MySQL on Solaris
* i5os-installation::            Installing MySQL on i5/OS
* netware-installation::         Installing MySQL on NetWare
* binary-installation::          Installing MySQL from Generic Binaries on Other Unix-Like Systems
* source-installation::          Installing MySQL from Source
* postinstallation::             Postinstallation Setup and Testing
* upgrading-downgrading::        Upgrading or Downgrading MySQL
* operating-system-specific-notes::  Operating System-Specific Notes
* environment-variables::        Environment Variables
* perl-support::                 Perl Installation Notes

End of Product Lifecycle

Active development for MySQL Database Server version 5.0 has ended.
Oracle offers various support offerings which may be of interest. For
details and more information, see the MySQL section of the Lifetime
Support Policy for Oracle Technology Products
(http://www.oracle.com/us/support/lifetime-support/index.html). Please
consider upgrading to a recent version.


File: manual.info,  Node: installation-overview,  Next: installation-version,  Prev: installing,  Up: installing

3.1 MySQL Installation Overview
===============================

This chapter describes how to obtain and install MySQL. You can choose
to install MySQL Enterprise or MySQL Community Server:

   * MySQL Enterprise is Oracle Corporation's commercial offering for
     modern enterprise businesses. It includes MySQL Enterprise Server
     and the services provided by MySQL Network. To install MySQL
     Enterprise, see *Note installing-es::.

   * MySQL Community Server is for users who are comfortable
     configuring and administering MySQL by themselves. To install
     MySQL Community Server, see *Note installing-cs::.

If you plan to upgrade an existing version of MySQL to a newer version
rather than install MySQL for the first time, see *Note upgrading::,
for information about upgrade procedures and about issues that you
should consider before upgrading.

If you are interested in migrating to MySQL from another database
system, you may wish to read *Note faqs-migration::, which contains
answers to some common questions concerning migration issues.


File: manual.info,  Node: installation-version,  Next: installing-es,  Prev: installation-overview,  Up: installing

3.2 Determining your current MySQL version
==========================================

To determine the version and release of your currently installed MySQL
installation, there are a number of options.

   * Using a command client (`mysql'), the server version of the MySQL
     server to which you are connected is shown once you are connected.
     The server version information includes `community' or `enterprise'
     accordingly.

     For example, here is the output from a MySQL Community Server
     edition installed on Linux:

          Welcome to the MySQL monitor.  Commands end with ; or \g.
          Your MySQL connection id is 6
          Server version: 5.0.27-standard MySQL Community Edition - Standard (GPL)

          Type 'help;' or '\h' for help. Type '\c' to clear the buffer.

          mysql>

     This is an example of the output from MySQL Enterprise Server on
     Windows:

          Welcome to the MySQL monitor.  Commands end with ; or \g.
          Your MySQL connection id is 2
          Server version: 5.0.28-enterprise-gpl-nt MySQL Enterprise Server (GPL)

          Type 'help;' or '\h' for help. Type '\c' to clear the buffer.

   * You may also determine the version information using the version
     variables. Both the version and version_comment variables contain
     version information for the server to which you are connected. Use
     the *Note `SHOW VARIABLES': show-variables. statement to obtain
     the information you want, as shown in this example:

          mysql> SHOW VARIABLES LIKE "%version%";
          +-------------------------+------------------------------------------+
          | Variable_name           | Value                                    |
          +-------------------------+------------------------------------------+
          | protocol_version        | 10                                       |
          | version                 | 5.0.27-standard                          |
          | version_comment         | MySQL Community Edition - Standard (GPL) |
          | version_compile_machine | i686                                     |
          | version_compile_os      | pc-linux-gnu                             |
          +-------------------------+------------------------------------------+
          5 rows in set (0.04 sec)

     You can also obtain server version information in the *Note
     `mysql': mysql. client using the *Note `SELECT': select.
     `VERSION()' statement. In addition, MySQL Administrator also shows
     the server version in the `Server Information' tab. However, in
     both of these cases, only the value of `version' is shown.

   * The `STATUS' command displays the version as well as version
     comment information. For example:

          mysql> STATUS;
          --------------
          ./client/mysql  Ver 14.12 Distrib 5.0.29, for pc-linux-gnu (i686) using readline 5.0

          Connection id:          8
          Current database:
          Current user:           mc@localhost
          SSL:                    Not in use
          Current pager:          /usr/bin/less
          Using outfile:          ''
          Using delimiter:        ;
          Server version:         5.0.27-standard MySQL Community Edition - Standard (GPL)
          Protocol version:       10
          Connection:             Localhost via UNIX socket
          Server characterset:    latin1
          Db     characterset:    latin1
          Client characterset:    latin1
          Conn.  characterset:    latin1
          UNIX socket:            /tmp/mysql.sock
          Uptime:                 1 day 3 hours 58 min 43 sec

          Threads: 2  Questions: 17  Slow queries: 0  Opens: 11  Flush tables: 1  Open tables: 6  Queries per second avg: 0.000
          --------------


File: manual.info,  Node: installing-es,  Next: installing-cs,  Prev: installation-version,  Up: installing

3.3 Notes for MySQL Enterprise Server
=====================================

* Menu:

* installing-es-disttypes::      Enterprise Server Distribution Types
* installing-es-upgrade::        Upgrading MySQL Enterprise Server

To obtain MySQL Enterprise, visit `http://enterprise.mysql.com' if
you're a customer.  Otherwise, visit
http://www.mysql.com/products/enterprise/. The platforms that are
officially supported for MySQL Enterprise are listed at
http://www.mysql.com/support/supportedplatforms.html.

MySQL Enterprise Server is available for download in the form of
_Quarterly Service Pack (QSP)_ or _Monthly Rapid Update (MRU)_ binary
releases.

To install MySQL Enterprise Server, you should use the latest available
Quarterly Service Pack (QSP). This includes an accumulation of the bug
fixes provided in all predecessor QSP and MRU releases.

MRU releases are provided on a monthly basis and represent the most
current Enterprise Server bug fixes. Each MRU is an accumulation of the
bug fixes included in its predecessor. Customers should standardize on
the latest MRU release only if it includes a needed bug fix.


File: manual.info,  Node: installing-es-disttypes,  Next: installing-es-upgrade,  Prev: installing-es,  Up: installing-es

3.3.1 Enterprise Server Distribution Types
------------------------------------------

Enterprise Server releases will be created for the following packages
from the MySQL 5.0 tree:

   * `mysql-enterprise': Released under a commercial license and
     includes the following storage engines: `MyISAM', `MEMORY',
     `MERGE', `InnoDB', `ARCHIVE', `BLACKHOLE', `EXAMPLE', `FEDERATED'.

   * `mysql-enterprise-gpl': Same as `mysql-enterprise', but released
     under the GPL.

   * `mysql-cluster': `mysql-enterprise' plus MySQL Cluster (*Note
     `NDB': mysql-cluster.).

   * `mysql-classic': Released under a commercial license, does not
     include `InnoDB'.

   * `mysql-community': Same as `mysql-enterprise-gpl', but available
     for the community, and released every 6 months.

To satisfy different user requirements, we provide several servers.
*Note `mysqld': mysqld. is an optimized server that is a smaller,
faster binary. *Note `mysqld-debug': mysqld. is compiled with debugging
support but is otherwise configured identically to the nondebug server.

Each of these servers is compiled from the same source distribution,
though with different configuration options. All native MySQL clients
can connect to servers from either MySQL version.


File: manual.info,  Node: installing-es-upgrade,  Prev: installing-es-disttypes,  Up: installing-es

3.3.2 Upgrading MySQL Enterprise Server
---------------------------------------

When upgrading to MySQL Enterprise from Community Server you need only
follow the installation process to install and upgrade the packages to
the latest version provided by MySQL Enterprise. You will also need to
install the latest MySQL Enterprise Service Pack and any outstanding
MySQL Hot-fix packs.

Be aware, however, that you must take into account any of the changes
when moving between major releases. You should also check the release
notes for details on major changes between revisions of MySQL
Enterprise Server (see *Note news::).

You should also review the notes and advice contained within *Note
upgrading::.


File: manual.info,  Node: installing-cs,  Next: getting-mysql,  Prev: installing-es,  Up: installing

3.4 Notes for MySQL Community Server
====================================

* Menu:

* installing-cs-overview::       Overview of MySQL Community Server Installation
* supported-os::                 Operating Systems Supported by MySQL Community Server
* which-version::                Choosing Which MySQL Distribution to Install


File: manual.info,  Node: installing-cs-overview,  Next: supported-os,  Prev: installing-cs,  Up: installing-cs

3.4.1 Overview of MySQL Community Server Installation
-----------------------------------------------------

  1. Determine whether MySQL runs and is supported on your platform

     Not all platforms are equally suitable for running MySQL, and not
     all platforms on which MySQL is known to run are officially
     supported by Oracle Corporation. For a list of platforms on which
     MySQL Community Server runs, see *Note supported-os::.

  2. Choose which distribution to install

     Several versions of MySQL are available, and most are available in
     multiple distribution formats. You can choose from prepackaged
     distributions containing binary (precompiled) programs or source
     code. When in doubt, use a binary distribution. We also provide
     public access to our current source trees for those who want to
     see our most recent developments and to help us test new code. To
     determine which version and type of distribution you should use,
     see *Note which-version::.

  3. Download the distribution that you want to install

     For download instructions, see *Note getting-mysql::. To verify
     the integrity of the distribution, use the instructions in *Note
     verifying-package-integrity::.

  4. Install the distribution

     To install MySQL from a binary distribution, use the instructions
     in *Note quick-standard-installation::. To install MySQL from a
     source distribution or from the current development source tree,
     use the instructions in *Note source-installation::.

     If you encounter installation difficulties, see *Note
     operating-system-specific-notes::, for information on solving
     problems for particular platforms.

  5. Perform any necessary postinstallation setup

     After installing MySQL, read *Note postinstallation::, which
     contains important information about making sure the MySQL server
     is working properly. It also describes how to secure the initial
     MySQL user accounts, _which have no passwords_ until you assign
     passwords. The information in this section applies whether you
     install MySQL using a binary or source distribution.

  6. Perform setup for running benchmarks (optional)

     If you want to use the MySQL benchmark scripts, Perl support for
     MySQL must be available. See *Note perl-support::, for more
     information.

The sections immediately following this one contain necessary
information about choosing, downloading, and verifying your
distribution. The instructions in later sections of the chapter
describe how to install the distribution that you choose. For binary
distributions, see the instructions in *Note
quick-standard-installation::. To build MySQL from source, use the
instructions in *Note source-installation::.


File: manual.info,  Node: supported-os,  Next: which-version,  Prev: installing-cs-overview,  Up: installing-cs

3.4.2 Operating Systems Supported by MySQL Community Server
-----------------------------------------------------------

This section lists the operating systems on which MySQL Community
Server is known to run.

*Important*:

Oracle Corporation does not necessarily provide official support for
all the platforms listed in this section. For information about those
platforms that are officially supported, see
http://www.mysql.com/support/supportedplatforms.html on the MySQL Web
site.

We use GNU Autoconf, so it is possible to port MySQL to all modern
systems that have a C++ compiler and a working implementation of POSIX
threads. (Thread support is needed for the server. To compile only the
client code, the only requirement is a C++ compiler.)

MySQL has been reported to compile successfully on the following
combinations of operating system and thread package.

   * AIX 4.x and 5.x with native threads. See *Note ibm-aix::. AIX 5.3
     should be upgraded to technology level 7 (5300-07).

   * Amiga.

   * FreeBSD 5.x and up with native threads.

   * HP-UX 11.x with native threads. See *Note hp-ux-11-x::.

   * Linux. Builds on all recent Linux distributions based on the 2.6
     kernel. See *Note linux::.

   * Mac OS X. See *Note macosx-installation::.

   * NetBSD 1.3/1.4 Intel and NetBSD 1.3 Alpha. See *Note netbsd::.

   * Novell NetWare 6.0 and 6.5. See *Note netware-installation::.

   * SCO OpenServer 5.0.X with a recent port of the FSU Pthreads
     package. See *Note sco::.

   * SCO Openserver 6.0.x. See *Note sco-openserver::.

   * SCO UnixWare 7.1.x. See *Note sco-unixware::.

   * SGI Irix 6.x with native threads. See *Note sgi-irix::.

   * Solaris 2.5 and above with native threads on SPARC and x86.  See
     *Note solaris::.

   * Tru64 Unix. See *Note alpha-dec-unix::.

   * Windows 2000, XP, Windows Server 2003, Windows Vista, and Windows
     Server 2008. See *Note windows-installation::.

MySQL has also been known to run on other systems in the past. See
*Note operating-system-specific-notes::. Some porting effort might be
required for current versions of MySQL on these systems.

Not all platforms are equally well suited for running MySQL. How well a
certain platform is suited for a high-load mission-critical MySQL
server is determined by the following factors:

   * General stability of the thread library

     A platform may have an excellent reputation otherwise, but MySQL
     is only as stable as the thread library it calls, even if
     everything else is perfect.

   * The capability of the kernel and the thread library to take
     advantage of symmetric multi-processor (SMP) systems

     When a process creates a thread, it should be possible for that
     thread to run on a CPU different from the original process.

   * Multi-threading and handling of mutexes

     The capability of the kernel and the thread library to run many
     threads that acquire and release a mutex over a short critical
     region frequently without excessive context switches. If the
     implementation of `pthread_mutex_lock()' does not easily yield CPU
     time, this hurts MySQL tremendously. If this issue is not taken
     care of, adding extra CPUs actually makes MySQL slower.

   * File system stability and performance

     MySQL's stability and performance are directly affected by those
     of the operating platform's file system. In particular, where
     large tables are in use, performance is affected by the ability of
     the file system to deal with large files at all and to deal with
     them efficiently.

   * Expertise with the platform

     If we know a platform well, we enable platform-specific
     optimizations and fixes at compile time. We can also provide
     advice on configuring your system optimally for MySQL. This is
     also affected by the amount of testing we have done internally for
     similar configurations, as well as by the number of users that
     have run MySQL successfully on the platform in similar
     configurations. If these figures are high, the likelihood of
     encountering platform-specific surprises is much smaller.


File: manual.info,  Node: which-version,  Prev: supported-os,  Up: installing-cs

3.4.3 Choosing Which MySQL Distribution to Install
--------------------------------------------------

* Menu:

* choosing-version::             Choosing Which Version of MySQL to Install
* choosing-distribution-format::  Choosing a Distribution Format
* many-versions::                How and When Updates Are Released
* mysql-binaries::               MySQL Binaries Compiled by Oracle Corporation

When preparing to install MySQL, you should decide which version to
use. MySQL development occurs in several release series, and you can
pick the one that best fits your needs. After deciding which version to
install, you can choose a distribution format.  Releases are available
in binary or source format.


File: manual.info,  Node: choosing-version,  Next: choosing-distribution-format,  Prev: which-version,  Up: which-version

3.4.3.1 Choosing Which Version of MySQL to Install
..................................................

The first decision to make is whether you want to use a production
(stable) release or a development release. In the MySQL development
process, multiple release series co-exist, each at a different stage of
maturity.

* Production Releases *
   * MySQL 5.5: Latest General Availability (Production) release

   * MySQL 5.1: Previous stable (production-quality) release

   * MySQL 5.0: Older stable release nearing the end of the product
     lifecycle

* Development Release *
   * MySQL 5.6: Current release under development (pre-Production)

MySQL 4.1, 4.0, and 3.23 are old releases that are no longer supported.

See http://www.mysql.com/about/legal/lifecycle/ for information about
support policies and schedules.

Normally, if you are beginning to use MySQL for the first time or
trying to port it to some system for which there is no binary
distribution, use the most recent General Availability series listed in
the preceding descriptions. All MySQL releases, even those from
development series, are checked with the MySQL benchmarks and an
extensive test suite before being issued.

If you are running an older system and want to upgrade, but do not want
to take the chance of having a nonseamless upgrade, you should upgrade
to the latest version in the same release series you are using (where
only the last part of the version number is newer than yours). We have
tried to fix only fatal bugs and make only small, relatively `safe'
changes to that version.

If you want to use new features not present in the production release
series, you can use a version from a development series.  Be aware that
development releases are not as stable as production releases.

We do not use a complete code freeze because this prevents us from
making bugfixes and other fixes that must be done. We may add small
things that should not affect anything that currently works in a
production release. Naturally, relevant bugfixes from an earlier series
propagate to later series.

If you want to use the very latest sources containing all current
patches and bugfixes, you can use one of our source code repositories
(see *Note installing-development-tree::). These are not `releases' as
such, but are available as previews of the code on which future
releases are to be based.

The naming scheme in MySQL 5.0 uses release names that consist of three
numbers and a suffix; for example, *mysql-5.0.14-rc*. The numbers
within the release name are interpreted as follows:

   * The first number (*5*) is the major version and describes the file
     format. All MySQL 5 releases have the same file format.

   * The second number (*0*) is the release level. Taken together, the
     major version and release level constitute the release series
     number.

   * The third number (*14*) is the version number within the release
     series. This is incremented for each new release. Usually you want
     the latest version for the series you have chosen.

For each minor update, the last number in the version string is
incremented. When there are major new features or minor
incompatibilities with previous versions, the second number in the
version string is incremented. When the file format changes, the first
number is increased.

Release names also include a suffix to indicates the stability level of
the release. Releases within a series progress through a set of
suffixes to indicate how the stability level improves.  The possible
suffixes are:

   * *alpha* indicates that the release is for preview purposes only.
     Known bugs should be documented in the News section (see *Note
     news::).  Most alpha releases implement new commands and
     extensions.  Active development that may involve major code
     changes can occur in an alpha release. However, we do conduct
     testing before issuing a release.

   * *beta* indicates that the release is appropriate for use with new
     development. Within beta releases, the features and compatibility
     should remain consistent. However, beta releases may contain
     numerous and major unaddressed bugs.

     No APIs, externally visible structures, or columns for SQL
     statements will change during future beta, release candidate, or
     production releases.

   * *rc* indicates a Release Candidate. Release candidates are
     believed to be stable, having passed all of MySQL's internal
     testing, and with all known fatal runtime bugs fixed. However, the
     release has not been in widespread use long enough to know for
     sure that all bugs have been identified. Only minor fixes are
     added. (A release candidate is what formerly was known as a gamma
     release.)

   * If there is no suffix, it indicates that the release is a General
     Availability (GA) or Production release. GA releases are stable,
     having successfully passed through all earlier release stages and
     are believed to be reliable, free of serious bugs, and suitable
     for use in production systems.  Only critical bugfixes are applied
     to the release.

All releases of MySQL are run through our standard tests and benchmarks
to ensure that they are relatively safe to use.  Because the standard
tests are extended over time to check for all previously found bugs,
the test suite keeps getting better.

All releases have been tested at least with these tools:

   * An internal test suite

     The `mysql-test' directory contains an extensive set of test
     cases. We run these tests for every server binary. See *Note
     mysql-test-suite::, for more information about this test suite.

   * The MySQL benchmark suite

     This suite runs a range of common queries. It is also a test to
     determine whether the latest batch of optimizations actually made
     the code faster. See *Note mysql-benchmarks::.

We also perform additional integration and nonfunctional testing of the
latest MySQL version in our internal production environment.
Integration testing is done with different connectors, storage engines,
replication modes, backup, partitioning, stored programs, and so forth
in various combinations. Additional nonfunctional testing is done in
areas of performance, concurrency, stress, high volume, upgrade and
downgrade.


File: manual.info,  Node: choosing-distribution-format,  Next: many-versions,  Prev: choosing-version,  Up: which-version

3.4.3.2 Choosing a Distribution Format
......................................

After choosing which version of MySQL to install, you should decide
whether to use a binary distribution or a source distribution. In most
cases, you should probably use a binary distribution, if one exists for
your platform. Binary distributions are available in native format for
many platforms, such as RPM files for Linux or PKG package installers
for Mac OS X or Solaris. Distributions also are available as Zip
archives or compressed `tar' files.

Reasons to choose a binary distribution include the following:

   * Binary distributions generally are easier to install than source
     distributions.

   * To satisfy different user requirements, we provide several servers
     in binary distributions. *Note `mysqld': mysqld.  is an optimized
     server that is a smaller, faster binary.  *Note `mysqld-debug':
     mysqld. is compiled with debugging support.

     Each of these servers is compiled from the same source
     distribution, though with different configuration options.  All
     native MySQL clients can connect to servers from either MySQL
     version.

Under some circumstances, you may be better off installing MySQL from a
source distribution:

   * You want to install MySQL at some explicit location. The standard
     binary distributions are ready to run at any installation
     location, but you might require even more flexibility to place
     MySQL components where you want.

   * You want to configure *Note `mysqld': mysqld. to ensure that
     features are available that might not be included in the standard
     binary distributions. Here is a list of the most common extra
     options that you may want to use to ensure feature availability:

        * `--with-berkeley-db' (not available on all platforms)

        * `--with-libwrap'

        * `--with-named-z-libs' (this is done for some of the binaries)

        * `--with-debug[=full]'

   * You want to configure *Note `mysqld': mysqld. without some
     features that are included in the standard binary distributions.
     For example, distributions normally are compiled with support for
     all character sets. If you want a smaller MySQL server, you can
     recompile it with support for only the character sets you need.

   * You want to use the latest sources from one of the Bazaar
     repositories to have access to all current bugfixes. For example,
     if you have found a bug and reported it to the MySQL development
     team, the bugfix is committed to the source repository and you can
     access it there. The bugfix does not appear in a release until a
     release actually is issued.

   * You want to read (or modify) the C and C++ code that makes up
     MySQL. For this purpose, you should get a source distribution,
     because the source code is always the ultimate manual.

   * Source distributions contain more tests and examples than binary
     distributions.


File: manual.info,  Node: many-versions,  Next: mysql-binaries,  Prev: choosing-distribution-format,  Up: which-version

3.4.3.3 How and When Updates Are Released
.........................................

MySQL is evolving quite rapidly and we want to share new developments
with other MySQL users. We try to produce a new release whenever we
have new and useful features that others also seem to have a need for.

We also try to help users who request features that are easy to
implement. We take note of what our licensed users want, and we
especially take note of what our support customers want and try to help
them in this regard.

No one is _required_ to download a new release. The `News' section
helps you determine whether the new release has something you really
want.  See *Note news::.

We use the following policy when updating MySQL:

   * Enterprise Server releases are meant to appear every 18 months,
     supplemented by quarterly service packs and monthly rapid updates.
     Community Server releases are meant to appear 2-3 times per year.

   * Releases are issued within each series. For each release, the last
     number in the version is one more than the previous release within
     the same series.

   * Binary distributions for some platforms are made by us for major
     releases. Other people may make binary distributions for other
     systems, but probably less frequently.

   * We make fixes available as soon as we have identified and
     corrected small or noncritical but annoying bugs. The fixes are
     available in source form immediately from our public Bazaar
     repositories, and are included in the next release.

   * If by any chance a security vulnerability or critical bug is found
     in a release, our policy is to fix it in a new release as soon as
     possible. (We would like other companies to do this, too!)


File: manual.info,  Node: mysql-binaries,  Prev: many-versions,  Up: which-version

3.4.3.4 MySQL Binaries Compiled by Oracle Corporation
.....................................................

Oracle Corporation provides a set of binary distributions of MySQL. In
addition to binaries provided in platform-specific package formats, we
offer binary distributions for a number of platforms in the form of
compressed `tar' files (`.tar.gz' files). See *Note
quick-standard-installation::. For Windows distributions, see *Note
windows-installation::.

If you want to compile MySQL from a source distribution, see *Note
source-installation::. To compile a debug version of MySQL, see *Note
source-configuration-options:: for options that enable debugging.


File: manual.info,  Node: getting-mysql,  Next: verifying-package-integrity,  Prev: installing-cs,  Up: installing

3.5 How to Get MySQL
====================

Check our downloads page at `http://dev.mysql.com/downloads/' for
information about the current version of MySQL and for downloading
instructions. For a complete up-to-date list of MySQL download mirror
sites, see `http://dev.mysql.com/downloads/mirrors.html'. You can also
find information there about becoming a MySQL mirror site and how to
report a bad or out-of-date mirror.

To obtain the latest development source, see *Note
installing-development-tree::.


File: manual.info,  Node: verifying-package-integrity,  Next: installation-layouts,  Prev: getting-mysql,  Up: installing

3.6 Verifying Package Integrity Using MD5 Checksums or `GnuPG'
==============================================================

* Menu:

* verifying-md5-checksum::       Verifying the MD5 Checksum
* checking-gpg-signature::       Signature Checking Using `GnuPG'
* checking-rpm-signature::       Signature Checking Using `RPM'

After you have downloaded the MySQL package that suits your needs and
before you attempt to install it, you should make sure that it is
intact and has not been tampered with. There are three means of
integrity checking:

   * MD5 checksums

   * Cryptographic signatures using `GnuPG', the GNU Privacy Guard

   * For RPM packages, the built-in RPM integrity verification mechanism

The following sections describe how to use these methods.

If you notice that the MD5 checksum or GPG signatures do not match,
first try to download the respective package one more time, perhaps
from another mirror site. If you repeatedly cannot successfully verify
the integrity of the package, please notify us about such incidents,
including the full package name and the download site you have been
using, at <webmaster@mysql.com> or <build@mysql.com>. Do not report
downloading problems using the bug-reporting system.


File: manual.info,  Node: verifying-md5-checksum,  Next: checking-gpg-signature,  Prev: verifying-package-integrity,  Up: verifying-package-integrity

3.6.1 Verifying the MD5 Checksum
--------------------------------

After you have downloaded a MySQL package, you should make sure that
its MD5 checksum matches the one provided on the MySQL download pages.
Each package has an individual checksum that you can verify with the
following command, where PACKAGE_NAME is the name of the package you
downloaded:

     shell> md5sum PACKAGE_NAME

Example:

     shell> md5sum mysql-standard-5.0.95-linux-i686.tar.gz
     aaab65abbec64d5e907dcd41b8699945  mysql-standard-5.0.95-linux-i686.tar.gz

You should verify that the resulting checksum (the string of
hexadecimal digits) matches the one displayed on the download page
immediately below the respective package.

*Note*:

Make sure to verify the checksum of the _archive file_ (for example,
the `.zip' or `.tar.gz' file) and not of the files that are contained
inside of the archive.

Note that not all operating systems support the `md5sum' command. On
some, it is simply called `md5', and others do not ship it at all. On
Linux, it is part of the *GNU Text Utilities* package, which is
available for a wide range of platforms. You can download the source
code from `http://www.gnu.org/software/textutils/' as well.  If you
have OpenSSL installed, you can use the command `openssl md5
PACKAGE_NAME' instead. A Windows implementation of the `md5' command
line utility is available from `http://www.fourmilab.ch/md5/'.
`winMd5Sum' is a graphical MD5 checking tool that can be obtained from
`http://www.nullriver.com/index/products/winmd5sum'.


File: manual.info,  Node: checking-gpg-signature,  Next: checking-rpm-signature,  Prev: verifying-md5-checksum,  Up: verifying-package-integrity

3.6.2 Signature Checking Using `GnuPG'
--------------------------------------

Another method of verifying the integrity and authenticity of a package
is to use cryptographic signatures. This is more reliable than using
MD5 checksums, but requires more work.

We sign MySQL downloadable packages with `GnuPG' (GNU Privacy Guard).
`GnuPG' is an Open Source alternative to the well-known Pretty Good
Privacy (`PGP') by Phil Zimmermann. See `http://www.gnupg.org/' for more
information about `GnuPG' and how to obtain and install it on your
system. Most Linux distributions ship with `GnuPG' installed by
default. For more information about `GnuPG', see
`http://www.openpgp.org/'.

To verify the signature for a specific package, you first need to
obtain a copy of our public GPG build key, which you can download from
`http://pgp.mit.com/'. The key that you want to obtain is named
`mysql-build@oss.oracle.com'. Alternatively, you can cut and paste the
key directly from the following text:

     -----BEGIN PGP PUBLIC KEY BLOCK-----
     Version: PGP Universal 2.9.1 (Build 347)

     mQGiBD4+owwRBAC14GIfUfCyEDSIePvEW3SAFUdJBtoQHH/nJKZyQT7h9bPlUWC3
     RODjQReyCITRrdwyrKUGku2FmeVGwn2u2WmDMNABLnpprWPkBdCk96+OmSLN9brZ
     fw2vOUgCmYv2hW0hyDHuvYlQA/BThQoADgj8AW6/0Lo7V1W9/8VuHP0gQwCgvzV3
     BqOxRznNCRCRxAuAuVztHRcEAJooQK1+iSiunZMYD1WufeXfshc57S/+yeJkegNW
     hxwR9pRWVArNYJdDRT+rf2RUe3vpquKNQU/hnEIUHJRQqYHo8gTxvxXNQc7fJYLV
     K2HtkrPbP72vwsEKMYhhr0eKCbtLGfls9krjJ6sBgACyP/Vb7hiPwxh6rDZ7ITnE
     kYpXBACmWpP8NJTkamEnPCia2ZoOHODANwpUkP43I7jsDmgtobZX9qnrAXw+uNDI
     QJEXM6FSbi0LLtZciNlYsafwAPEOMDKpMqAK6IyisNtPvaLd8lH0bPAnWqcyefep
     rv0sxxqUEMcM3o7wwgfN83POkDasDbs3pjwPhxvhz6//62zQJ7Q2TXlTUUwgUmVs
     ZWFzZSBFbmdpbmVlcmluZyA8bXlzcWwtYnVpbGRAb3NzLm9yYWNsZS5jb20+iGYE
     ExECACYCGyMGCwkIBwMCBBUCCAMEFgIDAQIeAQIXgAUCTnc+KgUJE/sCFQAKCRCM
     cY07UHLh9SbMAJ4l1+qBz2BZNSGCZwwA6YbhGPC7FwCgp8z5TzIw4YQuL5NGJ/sy
     0oSazqmJASIEEAECAAwFAk53QS4FAwASdQAACgkQlxC4m8pXrXwJ8Qf/be/UO9mq
     foc2sMyhwMpN4/fdBWwfLkA12FXQDOQMvwH9HsmEjnfUgYKXschZRi+DuHXe1P7l
     8G2aQLubhBsQf9ejKvRFTzuWMQkdIq+6Koulxv6ofkCcv3d1xtO2W7nb5yxcpVBP
     rRfGFGebJvZa58DymCNgyGtAU6AOz4veavNmI2+GIDQsY66+tYDvZ+CxwzdYu+HD
     V9HmrJfc6deM0mnBn7SRjqzxJPgoTQhihTav6q/R5/2p5NvQ/H84OgS6GjosfGc2
     duUDzCP/kheMRKfzuyKCOHQPtJuIj8++gfpHtEU7IDUX1So3c9n0PdpeBvclsDbp
     RnCNxQWU4mBot7kCDQQ+PqMdEAgA7+GJfxbMdY4wslPnjH9rF4N2qfWsEN/lxaZo
     JYc3a6M02WCnHl6ahT2/tBK2w1QI4YFteR47gCvtgb6O1JHffOo2HfLmRDRiRjd1
     DTCHqeyX7CHhcghj/dNRlW2Z0l5QFEcmV9U0Vhp3aFfWC4Ujfs3LU+hkAWzE7zaD
     5cH9J7yv/6xuZVw411x0h4UqsTcWMu0iM1BzELqX1DY7LwoPEb/O9Rkbf4fmLe11
     EzIaCa4PqARXQZc4dhSinMt6K3X4BrRsKTfozBu74F47D8Ilbf5vSYHbuE5p/1oI
     Dznkg/p8kW+3FxuWrycciqFTcNz215yyX39LXFnlLzKUb/F5GwADBQf+Lwqqa8CG
     rRfsOAJxim63CHfty5mUc5rUSnTslGYEIOCR1BeQauyPZbPDsDD9MZ1ZaSafanFv
     wFG6Llx9xkU7tzq+vKLoWkm4u5xf3vn55VjnSd1aQ9eQnUcXiL4cnBGoTbOWI39E
     cyzgslzBdC++MPjcQTcA7p6JUVsP6oAB3FQWg54tuUo0Ec8bsM8b3Ev42LmuQT5N
     dKHGwHsXTPtl0klk4bQk4OajHsiy1BMahpT27jWjJlMiJc+IWJ0mghkKHt926s/y
     mfdf5HkdQ1cyvsz5tryVI3Fx78XeSYfQvuuwqp2H139pXGEkg0n6KdUOetdZWhe7
     0YGNPw1yjWJT1IhUBBgRAgAMBQJOdz3tBQkT+wG4ABIHZUdQRwABAQkQjHGNO1By
     4fUUmwCbBYr2+bBEn/L2BOcnw9Z/QFWuhRMAoKVgCFm5fadQ3Afi+UQlAcOphrnJ
     =Eto8
     -----END PGP PUBLIC KEY BLOCK-----

To import the build key into your personal public GPG keyring, use `gpg
--import'. For example, if you have saved the key in a file named
`mysql_pubkey.asc', the import command looks like this:

     shell> gpg --import mysql_pubkey.asc
     gpg: key 5072E1F5: public key "MySQL Release Engineering
     <mysql-build@oss.oracle.com>" imported
     gpg: Total number processed: 1
     gpg:               imported: 1
     gpg: no ultimately trusted keys found

You can also download the key from the public keyserver using the
public key id, `5072E1F5':

     shell> gpg --recv-keys 5072E1F5
     gpg: requesting key 5072E1F5 from hkp server keys.gnupg.net
     gpg: key 5072E1F5: "MySQL Release Engineering <mysql-build@oss.oracle.com>"
     1 new user ID
     gpg: key 5072E1F5: "MySQL Release Engineering <mysql-build@oss.oracle.com>"
     53 new signatures
     gpg: no ultimately trusted keys found
     gpg: Total number processed: 1
     gpg:           new user IDs: 1
     gpg:         new signatures: 53

If you want to import the key into your RPM configuration to validate
RPM install packages, you should be able to import the key directly:

     shell> rpm --import mysql_pubkey.asc

If you experience problems, try exporting the key from `gpg' and
importing:

     shell> gpg --export -a 5072e1f5 > 5072e1f5.asc
     shell> rpm --import 5072e1f5.asc

Alternatively, `rpm' also supports loading the key directly from a URL,
and you cas use this manual page:

     shell> rpm --import http://dev.mysql.com/doc/refman/5.0/en/checking-gpg-signature.html

After you have downloaded and imported the public build key, download
your desired MySQL package and the corresponding signature, which also
is available from the download page. The signature file has the same
name as the distribution file with an `.asc' extension, as shown by the
examples in the following table.

*MySQL Package and Signature Files*

File Type          File Name
Distribution file  `mysql-standard-5.0.95-linux-i686.tar.gz'
Signature file     `mysql-standard-5.0.95-linux-i686.tar.gz.asc'

Make sure that both files are stored in the same directory and then run
the following command to verify the signature for the distribution file:

     shell> gpg --verify PACKAGE_NAME.asc

Example:

     shell> gpg --verify mysql-standard-5.0.95-linux-i686.tar.gz.asc
     gpg: Signature made Tue 01 Feb 2011 02:38:30 AM CST using DSA key ID 5072E1F5
     gpg: Good signature from "MySQL Release Engineering <mysql-build@oss.oracle.com>"

The `Good signature' message indicates that everything is all right.
You can ignore any `insecure memory' warning you might obtain.

See the GPG documentation for more information on how to work with
public keys.


File: manual.info,  Node: checking-rpm-signature,  Prev: checking-gpg-signature,  Up: verifying-package-integrity

3.6.3 Signature Checking Using `RPM'
------------------------------------

For RPM packages, there is no separate signature. RPM packages have a
built-in GPG signature and MD5 checksum. You can verify a package by
running the following command:

     shell> rpm --checksig PACKAGE_NAME.rpm

Example:

     shell> rpm --checksig MySQL-server-5.0.95-0.glibc23.i386.rpm
     MySQL-server-5.0.95-0.glibc23.i386.rpm: md5 gpg OK

*Note*:

If you are using RPM 4.1 and it shows the error `(GPG) NOT OK (MISSING
KEYS: GPG#5072e1f5)' even though you have imported the MySQL public
build key into your own GPG keyring, you need to import the key into
the RPM keyring first. RPM 4.1 no longer uses your personal GPG keyring
(or GPG itself). Rather, it maintains its own keyring because it is a
system-wide application and a user's GPG public keyring is a
user-specific file. To import the MySQL public key into the RPM keyring,
first obtain the key as described in *Note checking-gpg-signature::.
Then use `rpm --import' to import the key. For example, if you have
saved the public key in a file named `mysql_pubkey.asc', import it
using this command:

     shell> rpm --import mysql_pubkey.asc

If you need to obtain the MySQL public key, see *Note
checking-gpg-signature::.


File: manual.info,  Node: installation-layouts,  Next: compiler-characteristics,  Prev: verifying-package-integrity,  Up: installing

3.7 Installation Layouts
========================

This section describes the default layout of the directories created by
installing binary or source distributions provided by Oracle
Corporation. A distribution provided by another vendor might use a
layout different from those shown here.

For MySQL 5.0 on Windows, the default installation directory is
`C:\Program Files\MySQL\MySQL Server 5.0'. (Some Windows users prefer
to install in `C:\mysql', the directory that formerly was used as the
default. However, the layout of the subdirectories remains the same.)
The installation directory has the following subdirectories:

*MySQL Installation Layout for Windows*

Directory                        Contents of Directory
`bin'                            Client programs and the *Note `mysqld':
                                 mysqld. server
`data'                           Log files, databases
`examples'                       Example programs and scripts
`include'                        Include (header) files
`lib'                            Libraries
`scripts'                        Utility scripts
`share'                          Miscellaneous support files, including
                                 error messages, character set files,
                                 sample configuration files, SQL for
                                 database installation

Installations created from our Linux RPM distributions result in files
under the following system directories:

*MySQL Installation Layout for Linux RPM*

Directory                        Contents of Directory
`/usr/bin'                       Client programs and scripts
`/usr/sbin'                      The *Note `mysqld': mysqld. server
`/var/lib/mysql'                 Log files, databases
`/usr/share/info'                Manual in Info format
`/usr/share/man'                 Unix man pages
`/usr/include/mysql'             Include (header) files
`/usr/lib/mysql'                 Libraries
`/usr/share/mysql'               Miscellaneous support files, including
                                 error messages, character set files,
                                 sample configuration files, SQL for
                                 database installation
`/usr/share/sql-bench'           Benchmarks

On Unix, a `tar' file binary distribution is installed by unpacking it
at the installation location you choose (typically `/usr/local/mysql')
and creates the following directories in that location:

*MySQL Installation Layout for Generic Unix/Linux Binary Package*

Directory                        Contents of Directory
`bin'                            Client programs and the *Note `mysqld':
                                 mysqld. server
`data'                           Log files, databases
`docs'                           Manual in Info format
`man'                            Unix manual pages
`include'                        Include (header) files
`lib'                            Libraries
`scripts'                        *Note `mysql_install_db':
                                 mysql-install-db.
`share/mysql'                    Miscellaneous support files, including
                                 error messages, character set files,
                                 sample configuration files, SQL for
                                 database installation
`sql-bench'                      Benchmarks

By default, when you install MySQL after compiling it from a source
distribution, the installation step installs files under `/usr/local'.
Components are installed in the directories shown in the following
table. To configure particular installation locations, use the options
described at *Note source-configuration-options::.

*MySQL Layout for Installation from Source*

Directory                 Contents of Directory
`bin'                     Client programs and scripts
`include/mysql'           Include (header) files
`Docs'                    Manual in Info format
`man'                     Unix manual pages
`lib/mysql'               Libraries
`libexec'                 The *Note `mysqld': mysqld. server
`share/mysql'             Miscellaneous support files, including error
                          messages, character set files, sample
                          configuration files, SQL for database
                          installation
`sql-bench'               Benchmarks
`var'                     Log files, databases

Within its installation directory, the layout of a source installation
differs from that of a binary installation in the following ways:

   * The *Note `mysqld': mysqld. server is installed in the `libexec'
     directory rather than in the `bin' directory.

   * The data directory is `var' rather than `data'.

   * *Note `mysql_install_db': mysql-install-db. is installed in the
     `bin' directory rather than in the `scripts' directory.

   * The header file and library directories are `include/mysql' and
     `lib/mysql' rather than `include' and `lib'.

To create your own binary installation from a compiled source
distribution, execute the `scripts/make_binary_distribution' script from
the top directory of the source distribution.


File: manual.info,  Node: compiler-characteristics,  Next: quick-standard-installation,  Prev: installation-layouts,  Up: installing

3.8 Compiler-Specific Build Characteristics
===========================================

In some cases, the compiler used to build MySQL affects the features
available for use. The notes in this section apply for binary
distributions provided by Oracle Corporation or that you compile
yourself from source.

*`icc' (Intel C++ Compiler) Builds*

A server built with `icc' has these characteristics:

   * SSL support is not included.


File: manual.info,  Node: quick-standard-installation,  Next: windows-installation,  Prev: compiler-characteristics,  Up: installing

3.9 Standard MySQL Installation from a Binary Distribution
==========================================================

The next several sections cover the installation of MySQL on platforms
where we offer packages using the native packaging format of the
respective platform. (This is also known as performing a binary
installation.) However, binary distributions of MySQL are available for
many other platforms as well. See *Note binary-installation::, for
generic installation instructions for these packages that apply to all
platforms.

See *Note installing-cs::, for more information on what other binary
distributions are available and how to obtain them.


File: manual.info,  Node: windows-installation,  Next: macosx-installation,  Prev: quick-standard-installation,  Up: installing

3.10 Installing MySQL on Microsoft Windows
==========================================

* Menu:

* windows-choosing-package::     Choosing An Installation Package
* windows-using-installer::      Installing MySQL on Microsoft Windows Using an MSI Package
* mysql-config-wizard::          MySQL Server Instance Configuration Wizard
* windows-install-archive::      Installing MySQL on Microsoft Windows Using a `noinstall' Zip Archive
* windows-troubleshooting::      Troubleshooting a MySQL Installation Under Windows
* windows-upgrading::            Upgrading MySQL on Windows
* windows-postinstallation::     Windows Postinstallation Procedures
* windows-source-build::         Installing MySQL from Source on Windows

A native Windows distribution of MySQL has been available since version
3.21 and represents a sizable percentage of the daily downloads of
MySQL. This section describes the process for installing MySQL on
Windows.

*Note*:

If you are upgrading MySQL from an existing installation older than
MySQL 4.1.5, you must first perform the procedure described in *Note
windows-upgrading::.

To run MySQL on Windows, you need the following:

   * A Windows operating system such as 2000, XP, Vista, Server 2008,
     or newer. Only 32-bit and 64-bit versions of Windows 2000 and
     later are supported. Windows 95/98/ME and versions of Windows
     older than these are no longer supported.

     A Windows operating system permits you to run the MySQL server as
     a service. See *Note windows-start-service::.

     Generally, you should install MySQL on Windows using an account
     that has administrator rights. Otherwise, you may encounter
     problems with certain operations such as editing the `PATH'
     environment variable or accessing the `Service Control Manager'.

   * TCP/IP protocol support.

   * Enough space on the hard drive to unpack, install, and create the
     databases in accordance with your requirements (generally a
     minimum of 200 megabytes is recommended.)

For a list of limitations within the Windows version of MySQL, see
*Note limits-windows::.

There may also be other requirements, depending on how you plan to use
MySQL:

   * If you plan to connect to the MySQL server using ODBC, you need a
     Connector/ODBC driver. See *Note connectors-apis::.

   * If you need tables with a size larger than 4GB, install MySQL on
     an NTFS or newer file system. Do not forget to use `MAX_ROWS' and
     `AVG_ROW_LENGTH' when you create tables. See *Note create-table::.

MySQL for Windows is available in several distribution formats:

   * Binary distributions are available that contain a setup program
     that installs everything you need so that you can start the server
     immediately. Another binary distribution format contains an
     archive that you simply unpack in the installation location and
     then configure yourself. For details, see *Note
     windows-choosing-package::.

   * The source distribution contains all the code and support files
     for building the executables using the Visual Studio compiler
     system.

Generally speaking, you should use a binary distribution that includes
an installer. It is simpler to use than the others, and you need no
additional tools to get MySQL up and running. The installer for the
Windows version of MySQL, combined with a GUI Configuration Wizard,
automatically installs MySQL, creates an option file, starts the
server, and secures the default user accounts.

*Caution*:

Using virus scanning software such as Norton/Symantec Anti-Virus on
directories containing MySQL data and temporary tables can cause
issues, both in terms of the performance of MySQL and the
virus-scanning software mis-identifying the contents of the files as
containing spam. This is because of the fingerprinting mechanism used
by the virus scanning software, and the way in which MySQL rapidly
updates different files, which may be identified as a potential
security risk.

After installing MySQL Server, it is recommended that you disable virus
scanning on the main directory (`datadir') being used to store your
MySQL table data. There is usually a system built into the virus
scanning software to permit certain directories to be specifically
ignored during virus scanning.

In addition, by default, MySQL creates temporary files in the standard
Windows temporary directory. To prevent the temporary files also being
scanned, you should configure a separate temporary directory for MySQL
temporary files and add this to the virus scanning exclusion list. To
do this, add a configuration option for the `tmpdir' parameter to your
`my.ini' configuration file. For more information, see *Note
windows-create-option-file::.

The following section describes how to install MySQL on Windows using a
binary distribution. To use an installation package that does not
include an installer, follow the procedure described in *Note
windows-install-archive::. To install using a source distribution, see
*Note windows-source-build::.

MySQL distributions for Windows can be downloaded from
`http://dev.mysql.com/downloads/'. See *Note getting-mysql::.


File: manual.info,  Node: windows-choosing-package,  Next: windows-using-installer,  Prev: windows-installation,  Up: windows-installation

3.10.1 Choosing An Installation Package
---------------------------------------

For MySQL 5.0, there are three installation package formats to choose
from when installing MySQL on Windows:

   * The Essentials package

     This package has a file name similar to
     `mysql-essential-5.0.95-win32.msi' and contains the minimum set of
     files needed to install MySQL on Windows, including the
     Configuration Wizard. This package does not include optional
     components such as the embedded server and benchmark suite.

   * The Complete package

     This package has a file name similar to `mysql-5.0.95-win32.zip'
     and contains all files needed for a complete Windows installation,
     including the Configuration Wizard. This package includes optional
     components such as the embedded server and benchmark suite.

   * The no-install archive

     This package has a file name similar to
     `mysql-noinstall-5.0.95-win32.zip' and contains all the files
     found in the Complete install package, with the exception of the
     Configuration Wizard.  This package does not include an automated
     installer, and must be manually installed and configured.

The Essentials package is recommended for most users. It is provided as
an `.msi' file for use with the Windows Installer. The Complete and
Noinstall distributions are packaged as Zip archives. To use them, you
must have a tool that can unpack `.zip' files.

Your choice of install package affects the installation process you
must follow. If you choose to install either an Essentials or Complete
install package, see *Note windows-using-installer::. If you choose to
install a Noinstall archive, see *Note windows-install-archive::.


File: manual.info,  Node: windows-using-installer,  Next: mysql-config-wizard,  Prev: windows-choosing-package,  Up: windows-installation

3.10.2 Installing MySQL on Microsoft Windows Using an MSI Package
-----------------------------------------------------------------

* Menu:

* windows-install-wizard::       Using the MySQL Installation Wizard

New MySQL users can use the MySQL Installation Wizard and MySQL
Configuration Wizard to install MySQL on Windows. These are designed to
install and configure MySQL in such a way that new users can
immediately get started using MySQL.

The MySQL Installation Wizard and MySQL Configuration Wizard are
available in the Essentials and Complete install packages. They are
recommended for most standard MySQL installations. Exceptions include
users who need to install multiple instances of MySQL on a single
server host and advanced users who want complete control of server
configuration.


File: manual.info,  Node: windows-install-wizard,  Prev: windows-using-installer,  Up: windows-using-installer

3.10.2.1 Using the MySQL Installation Wizard
............................................

* Menu:

* mysql-install-wizard-starting::  Downloading and Starting the MySQL Installation Wizard
* mysql-install-wizard-install-type::  Choosing an Installation Type
* mysql-install-wizard-custom-install::  The Custom Installation Dialog
* mysql-install-wizard-confirmation-dialog::  The Confirmation Dialog
* mysql-install-wizard-changes::  Changes Made by MySQL Installation Wizard
* mysql-install-wizard-upgrading::  Upgrading MySQL with the Installation Wizard

MySQL Installation Wizard is an installer for the MySQL server that
uses the latest installer technologies for Microsoft Windows. The MySQL
Installation Wizard, in combination with the MySQL Configuration
Wizard, enables a user to install and configure a MySQL server that is
ready for use immediately after installation.

The MySQL Installation Wizard is the standard installer for all MySQL
server distributions, version 4.1.5 and higher. Users of previous
versions of MySQL need to shut down and remove their existing MySQL
installations manually before installing MySQL with the MySQL
Installation Wizard. See *Note mysql-install-wizard-upgrading::, for
more information on upgrading from a previous version.

The Microsoft Windows Installer (MSI) is the standard for application
installations on Windows 2000 and later versions.  The MySQL
Installation Wizard makes use of this technology to provide a smoother
and more flexible installation process.

The Microsoft Windows Installer Engine was updated with the release of
Windows XP; those using a previous version of Windows can reference
this Microsoft Knowledge Base article
(http://support.microsoft.com/default.aspx?scid=kb;EN-US;292539) for
information on upgrading to the latest version of the Windows Installer
Engine.

In addition, Microsoft has introduced the WiX (Windows Installer XML)
toolkit, which is the first highly acknowledged Open Source project
from Microsoft. We have switched to WiX because it is an Open Source
project and it enables us to handle the complete Windows installation
process in a flexible manner using scripts.

Improving the MySQL Installation Wizard depends on the support and
feedback of users. If you find that the MySQL Installation Wizard is
lacking some feature important to you, or if you discover a bug, please
report it in our bugs database using the instructions given in *Note
bug-reports::.


File: manual.info,  Node: mysql-install-wizard-starting,  Next: mysql-install-wizard-install-type,  Prev: windows-install-wizard,  Up: windows-install-wizard

3.10.2.2 Downloading and Starting the MySQL Installation Wizard
...............................................................

MySQL installation packages can be downloaded from
`http://dev.mysql.com/downloads/'. If the package you download is
contained within a Zip archive, you need to extract the archive first.

*Note*:

If you are installing on Windows Vista or newer, it is best to open a
network port for MySQL to use before beginning the installation. To do
this, first ensure that you are logged in as an Administrator, then go
to the `Control Panel' and double-click the `Windows Firewall' icon.
Choose the `Allow a program through Windows Firewall' option and click
the `Add port' button. Enter `MySQL' into the `Name' text box and
`3306' (or other port of your choice) into the `Port number' text box.
Also ensure that the `TCP' protocol radio button is selected. If you
wish, you can also limit access to the MySQL server by choosing the
`Change scope' button. Confirm your choices by clicking the `OK'
button. If you do not open a port prior to installation, you cannot
configure the MySQL server immediately after installation.
Additionally, when running the MySQL Installation Wizard on Windows
Vista or newer, ensure that you are logged in as a user with
administrative rights.

The process for starting the wizard depends on the contents of the
installation package you download. If there is a `setup.exe' file
present, double-click it to start the installation process. If there is
an `.msi' file present, double-click it to start the installation
process.

MySQL Installer Main Screen (Windows)


File: manual.info,  Node: mysql-install-wizard-install-type,  Next: mysql-install-wizard-custom-install,  Prev: mysql-install-wizard-starting,  Up: windows-install-wizard

3.10.2.3 Choosing an Installation Type
......................................

There are three installation types available: *Typical*, *Complete*, and
*Custom*.

MySQL Installer Setup type (Windows)

The *Typical* installation type installs the MySQL server, the *Note
`mysql': mysql.  command-line client, and the command-line utilities.
The command-line clients and utilities include *Note `mysqldump':
mysqldump, *Note `myisamchk': myisamchk, and several other tools to
help you manage the MySQL server.

The *Complete* installation type installs all components included in
the installation package. The full installation package includes
components such as the embedded server library, the benchmark suite,
support scripts, and documentation.

The *Custom* installation type gives you complete control over which
packages you wish to install and the installation path that is used. See
*Note mysql-install-wizard-custom-install::, for more information on
performing a custom install.

If you choose the *Typical* or *Complete* installation types and click
the `Next' button, you advance to the confirmation screen to verify
your choices and begin the installation. If you choose the *Custom*
installation type and click the `Next' button, you advance to the
custom installation dialog, described in *Note
mysql-install-wizard-custom-install::.


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3.10.2.4 The Custom Installation Dialog
.......................................

If you wish to change the installation path or the specific components
that are installed by the MySQL Installation Wizard, choose the *Custom*
installation type.

MySQL Installer Custom Installation (Windows)

A tree view on the left side of the custom install dialog lists all
available components. Components that are not installed have a red `X'
icon; components that are installed have a gray icon. To change whether
a component is installed, click that component's icon and choose a new
option from the drop-down list that appears.

You can change the default installation path by clicking the
`Change...' button to the right of the displayed installation path.

After choosing your installation components and installation path,
click the `Next' button to advance to the confirmation dialog.


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3.10.2.5 The Confirmation Dialog
................................

Once you choose an installation type and optionally choose your
installation components, you advance to the confirmation dialog. Your
installation type and installation path are displayed for you to review.

MySQL Installer Installation Summary (Windows)

To install MySQL if you are satisfied with your settings, click the
`Install' button. To change your settings, click the `Back' button.  To
exit the MySQL Installation Wizard without installing MySQL, click the
`Cancel' button.

After installation is complete, you have the option of registering with
the MySQL Web site. Registration gives you access to post in the MySQL
forums at forums.mysql.com (http://forums.mysql.com), along with the
ability to report bugs at bugs.mysql.com (http://bugs.mysql.com) and to
subscribe to our newsletter. The final screen of the installer provides
a summary of the installation and gives you the option to launch the
MySQL Configuration Wizard, which you can use to create a configuration
file, install the MySQL service, and configure security settings.


File: manual.info,  Node: mysql-install-wizard-changes,  Next: mysql-install-wizard-upgrading,  Prev: mysql-install-wizard-confirmation-dialog,  Up: windows-install-wizard

3.10.2.6 Changes Made by MySQL Installation Wizard
..................................................

Once you click the `Install' button, the MySQL Installation Wizard
begins the installation process and makes certain changes to your
system which are described in the sections that follow.

*Changes to the Registry*

The MySQL Installation Wizard creates one Windows registry key in a
typical install situation, located in
`HKEY_LOCAL_MACHINE\SOFTWARE\MySQL AB'.

The MySQL Installation Wizard creates a key named after the major
version of the server that is being installed, such as `MySQL Server
5.0'. It contains two string values, `Location' and `Version'. The
`Location' string contains the path to the installation directory. In a
default installation it contains `C:\Program Files\MySQL\MySQL Server
5.0\'. The `Version' string contains the release number.  For example,
for an installation of MySQL Server 5.0.95, the key contains a value of
`5.0.95'.

These registry keys are used to help external tools identify the
installed location of the MySQL server, preventing a complete scan of
the hard-disk to determine the installation path of the MySQL server.
The registry keys are not required to run the server, and if you
install MySQL using the `noinstall' Zip archive, the registry keys are
not created.

*Changes to the Start Menu*

The MySQL Installation Wizard creates a new entry in the Windows
`Start' menu under a common MySQL menu heading named after the major
version of MySQL that you have installed. For example, if you install
MySQL 5.0, the MySQL Installation Wizard creates a `MySQL Server 5.0'
section in the `Start' menu.

The following entries are created within the new `Start' menu section:

   * `MySQL Command Line Client': This is a shortcut to the *Note
     `mysql': mysql. command-line client and is configured to connect
     as the `root' user. The shortcut prompts for a `root' user
     password when you connect.

   * `MySQL Server Instance Config Wizard': This is a shortcut to the
     MySQL Configuration Wizard. Use this shortcut to configure a newly
     installed server, or to reconfigure an existing server.

   * `MySQL Documentation': This is a link to the MySQL server
     documentation that is stored locally in the MySQL server
     installation directory. This option is not available when the
     MySQL server is installed using the Essentials installation
     package.

*Changes to the File System*

The MySQL Installation Wizard by default installs the MySQL 5.0 server
to `C:\PROGRAM FILES\MySQL\MySQL Server 5.0', where PROGRAM FILES is
the default location for applications in your system, and 5.0 is the
major version of your MySQL server. This is the recommended location
for the MySQL server, replacing the former default location `C:\mysql'.

By default, all MySQL applications are stored in a common directory at
`C:\PROGRAM FILES\MySQL', where PROGRAM FILES is the default location
for applications in your Windows installation. A typical MySQL
installation on a developer machine might look like this:

     C:\Program Files\MySQL\MySQL Server 5.0
     C:\Program Files\MySQL\MySQL Workbench 5.1 OSS

This approach makes it easier to manage and maintain all MySQL
applications installed on a particular system.


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3.10.2.7 Upgrading MySQL with the Installation Wizard
.....................................................

The MySQL Installation Wizard can perform server upgrades automatically
using the upgrade capabilities of MSI. That means you do not need to
remove a previous installation manually before installing a new
release. The installer automatically shuts down and removes the
previous MySQL service before installing the new version.

Automatic upgrades are available only when upgrading between
installations that have the same major and minor version numbers. For
example, you can upgrade automatically from MySQL 5.0.5 to MySQL 5.0.6,
but not from MySQL 4.1 to MySQL 5.0.

See *Note windows-upgrading::.


File: manual.info,  Node: mysql-config-wizard,  Next: windows-install-archive,  Prev: windows-using-installer,  Up: windows-installation

3.10.3 MySQL Server Instance Configuration Wizard
-------------------------------------------------

* Menu:

* mysql-config-wizard-starting::  Starting the MySQL Server Instance Configuration Wizard
* mysql-config-wizard-maintenance::  Choosing a Maintenance Option
* mysql-config-wizard-configuration-type::  Choosing a Configuration Type
* mysql-config-wizard-server-type::  The Server Type Dialog
* mysql-config-wizard-database-usage::  The Database Usage Dialog
* mysql-config-wizard-tablespace::  The InnoDB Tablespace Dialog
* mysql-config-wizard-connections::  The Concurrent Connections Dialog
* mysql-config-wizard-networking::  The Networking and Strict Mode Options Dialog
* mysql-config-wizard-character-set::  The Character Set Dialog
* mysql-config-wizard-service::  The Service Options Dialog
* mysql-config-wizard-security::  The Security Options Dialog
* mysql-config-wizard-confirmation::  The Confirmation Dialog

The MySQL Server Instance Configuration Wizard helps automate the
process of configuring your server. It creates a custom MySQL
configuration file (`my.ini' or `my.cnf') by asking you a series of
questions and then applying your responses to a template to generate the
configuration file that is tuned to your installation.

The MySQL Server Instance Configuration Wizard is included with the
MySQL 5.0 server. The MySQL Server Instance Configuration Wizard is
only available for Windows.


File: manual.info,  Node: mysql-config-wizard-starting,  Next: mysql-config-wizard-maintenance,  Prev: mysql-config-wizard,  Up: mysql-config-wizard

3.10.3.1 Starting the MySQL Server Instance Configuration Wizard
................................................................

The MySQL Server Instance Configuration Wizard is normally started as
part of the installation process. You should only need to run the MySQL
Server Instance Configuration Wizard again when you need to change the
configuration parameters of your server.

If you chose not to open a port prior to installing MySQL on Windows
Vista or newer, you can choose to use the MySQL Server Configuration
Wizard after installation. However, you must open a port in the Windows
Firewall. To do this see the instructions given in *Note
mysql-install-wizard-starting::. Rather than opening a port, you also
have the option of adding MySQL as a program that bypasses the Windows
Firewall. One or the other option is sufficient--you need not do both.
Additionally, when running the MySQL Server Configuration Wizard on
Windows Vista or newer, ensure that you are logged in as a user with
administrative rights.

MySQL Server Instance Configuration Wizard

You can launch the MySQL Configuration Wizard by clicking the `MySQL
Server Instance Config Wizard' entry in the `MySQL' section of the
Windows `Start' menu.

Alternatively, you can navigate to the `bin' directory of your MySQL
installation and launch the `MySQLInstanceConfig.exe' file directly.

The MySQL Server Instance Configuration Wizard places the `my.ini' file
in the installation directory for the MySQL server. This helps
associate configuration files with particular server instances.

To ensure that the MySQL server knows where to look for the `my.ini'
file, an argument similar to this is passed to the MySQL server as part
of the service installation:

     --defaults-file="C:\PROGRAM FILES\MYSQL\MYSQL SERVER 5.0\my.ini"

Here, C:\PROGRAM FILES\MYSQL\MYSQL SERVER 5.0 is replaced with the
installation path to the MySQL Server. The `--defaults-file' option
instructs the MySQL server to read the specified file for configuration
options when it starts.

Apart from making changes to the `my.ini' file by running the MySQL
Server Instance Configuration Wizard again, you can modify it by
opening it with a text editor and making any necessary changes. You can
also modify the server configuration with the
http://www.mysql.com/products/administrator/ utility. For more
information about server configuration, see *Note server-options::.

MySQL clients and utilities such as the *Note `mysql': mysql.  and
*Note `mysqldump': mysqldump. command-line clients are not able to
locate the `my.ini' file located in the server installation directory.
To configure the client and utility applications, create a new `my.ini'
file in the Windows installation directory (for example, `C:\WINDOWS').

Under Windows Server 2003, Windows Server 2000 and Windows XP, MySQL
Server Instance Configuration Wizard will configure MySQL to work as a
Windows service. To start and stop MySQL you use the `Services'
application that is supplied as part of the Windows Administrator Tools.


File: manual.info,  Node: mysql-config-wizard-maintenance,  Next: mysql-config-wizard-configuration-type,  Prev: mysql-config-wizard-starting,  Up: mysql-config-wizard

3.10.3.2 Choosing a Maintenance Option
......................................

If the MySQL Server Instance Configuration Wizard detects an existing
configuration file, you have the option of either reconfiguring your
existing server, or removing the server instance by deleting the
configuration file and stopping and removing the MySQL service.

To reconfigure an existing server, choose the `Re-configure Instance'
option and click the `Next' button. Any existing configuration file is
not overwritten, but renamed (within the same directory) using a
timestamp (Windows) or sequential number (Linux). To remove the
existing server instance, choose the `Remove Instance' option and click
the `Next' button.

If you choose the `Remove Instance' option, you advance to a
confirmation window. Click the `Execute' button. The MySQL Server
Configuration Wizard stops and removes the MySQL service, and then
deletes the configuration file. The server installation and its `data'
folder are not removed.

If you choose the `Re-configure Instance' option, you advance to the
`Configuration Type' dialog where you can choose the type of
installation that you wish to configure.


File: manual.info,  Node: mysql-config-wizard-configuration-type,  Next: mysql-config-wizard-server-type,  Prev: mysql-config-wizard-maintenance,  Up: mysql-config-wizard

3.10.3.3 Choosing a Configuration Type
......................................

When you start the MySQL Server Instance Configuration Wizard for a new
MySQL installation, or choose the `Re-configure Instance' option for an
existing installation, you advance to the `Configuration Type' dialog.

MySQL Server Instance Configuration Wizard: Configuration Type

There are two configuration types available: `Detailed Configuration'
and `Standard Configuration'. The `Standard Configuration' option is
intended for new users who want to get started with MySQL quickly
without having to make many decisions about server configuration. The
`Detailed Configuration' option is intended for advanced users who want
more fine-grained control over server configuration.

If you are new to MySQL and need a server configured as a single-user
developer machine, the `Standard Configuration' should suit your needs.
Choosing the `Standard Configuration' option causes the MySQL
Configuration Wizard to set all configuration options automatically
with the exception of `Service Options' and `Security Options'.

The `Standard Configuration' sets options that may be incompatible with
systems where there are existing MySQL installations. If you have an
existing MySQL installation on your system in addition to the
installation you wish to configure, the `Detailed Configuration' option
is recommended.

To complete the `Standard Configuration', please refer to the sections
on `Service Options' and `Security Options' in *Note
mysql-config-wizard-service::, and *Note
mysql-config-wizard-security::, respectively.


File: manual.info,  Node: mysql-config-wizard-server-type,  Next: mysql-config-wizard-database-usage,  Prev: mysql-config-wizard-configuration-type,  Up: mysql-config-wizard

3.10.3.4 The Server Type Dialog
...............................

There are three different server types available to choose from.  The
server type that you choose affects the decisions that the MySQL Server
Instance Configuration Wizard makes with regard to memory, disk, and
processor usage.

MySQL Server Instance Configuration Wizard: Server Type

   * `Developer Machine': Choose this option for a typical desktop
     workstation where MySQL is intended only for personal use. It is
     assumed that many other desktop applications are running. The
     MySQL server is configured to use minimal system resources.

   * `Server Machine': Choose this option for a server machine where
     the MySQL server is running alongside other server applications
     such as FTP, email, and Web servers. The MySQL server is
     configured to use a moderate portion of the system resources.

   * `Dedicated MySQL Server Machine': Choose this option for a server
     machine that is intended to run only the MySQL server. It is
     assumed that no other applications are running. The MySQL server
     is configured to use all available system resources.

*Note*:

By selecting one of the preconfigured configurations, the values and
settings of various options in your `my.cnf' or `my.ini' will be
altered accordingly. The default values and options as described in the
reference manual may therefore be different to the options and values
that were created during the execution of the configuration wizard.


File: manual.info,  Node: mysql-config-wizard-database-usage,  Next: mysql-config-wizard-tablespace,  Prev: mysql-config-wizard-server-type,  Up: mysql-config-wizard

3.10.3.5 The Database Usage Dialog
..................................

The `Database Usage' dialog enables you to indicate the storage engines
that you expect to use when creating MySQL tables. The option you
choose determines whether the `InnoDB' storage engine is available and
what percentage of the server resources are available to `InnoDB'.

MySQL Server Instance Configuration Wizard: Usage Dialog

   * `Multifunctional Database': This option enables both the `InnoDB'
     and `MyISAM' storage engines and divides resources evenly between
     the two. This option is recommended for users who use both storage
     engines on a regular basis.

   * `Transactional Database Only': This option enables both the
     `InnoDB' and `MyISAM' storage engines, but dedicates most server
     resources to the `InnoDB' storage engine. This option is
     recommended for users who use `InnoDB' almost exclusively and make
     only minimal use of `MyISAM'.

   * `Non-Transactional Database Only': This option disables the
     `InnoDB' storage engine completely and dedicates all server
     resources to the `MyISAM' storage engine. This option is
     recommended for users who do not use `InnoDB'.

The Configuration Wizard uses a template to generate the server
configuration file. The `Database Usage' dialog sets one of the
following option strings:

     Multifunctional Database:        MIXED
     Transactional Database Only:     INNODB
     Non-Transactional Database Only: MYISAM

When these options are processed through the default template
(my-template.ini) the result is:

     Multifunctional Database:
     default-storage-engine=InnoDB
     _myisam_pct=50

     Transactional Database Only:
     default-storage-engine=InnoDB
     _myisam_pct=5

     Non-Transactional Database Only:
     default-storage-engine=MyISAM
     _myisam_pct=100
     skip-innodb

The `_myisam_pct' value is used to calculate the percentage of
resources dedicated to `MyISAM'. The remaining resources are allocated
to `InnoDB'.


File: manual.info,  Node: mysql-config-wizard-tablespace,  Next: mysql-config-wizard-connections,  Prev: mysql-config-wizard-database-usage,  Up: mysql-config-wizard

3.10.3.6 The InnoDB Tablespace Dialog
.....................................

Some users may want to locate the `InnoDB' tablespace files in a
different location than the MySQL server data directory. Placing the
tablespace files in a separate location can be desirable if your system
has a higher capacity or higher performance storage device available,
such as a RAID storage system.

MySQL Server Instance Configuration Wizard: InnoDB Data Tablespace

To change the default location for the `InnoDB' tablespace files,
choose a new drive from the drop-down list of drive letters and choose
a new path from the drop-down list of paths. To create a custom path,
click the `...' button.

If you are modifying the configuration of an existing server, you must
click the `Modify' button before you change the path. In this situation
you must move the existing tablespace files to the new location
manually before starting the server.


File: manual.info,  Node: mysql-config-wizard-connections,  Next: mysql-config-wizard-networking,  Prev: mysql-config-wizard-tablespace,  Up: mysql-config-wizard

3.10.3.7 The Concurrent Connections Dialog
..........................................

To prevent the server from running out of resources, it is important to
limit the number of concurrent connections to the MySQL server that can
be established. The `Concurrent Connections' dialog enables you to
choose the expected usage of your server, and sets the limit for
concurrent connections accordingly. It is also possible to set the
concurrent connection limit manually.

MySQL Server Instance Configuration Wizard: Connections

   * `Decision Support (DSS)/OLAP': Choose this option if your server
     does not require a large number of concurrent connections. The
     maximum number of connections is set at 100, with an average of 20
     concurrent connections assumed.

   * `Online Transaction Processing (OLTP)': Choose this option if your
     server requires a large number of concurrent connections. The
     maximum number of connections is set at 500.

   * `Manual Setting': Choose this option to set the maximum number of
     concurrent connections to the server manually. Choose the number
     of concurrent connections from the drop-down box provided, or
     enter the maximum number of connections into the drop-down box if
     the number you desire is not listed.


File: manual.info,  Node: mysql-config-wizard-networking,  Next: mysql-config-wizard-character-set,  Prev: mysql-config-wizard-connections,  Up: mysql-config-wizard

3.10.3.8 The Networking and Strict Mode Options Dialog
......................................................

Use the `Networking Options' dialog to enable or disable TCP/IP
networking and to configure the port number that is used to connect to
the MySQL server.

MySQL Server Instance Configuration Wizard: Network Configuration

TCP/IP networking is enabled by default. To disable TCP/IP networking,
uncheck the box next to the `Enable TCP/IP Networking' option.

Port 3306 is used by default. To change the port used to access MySQL,
choose a new port number from the drop-down box or type a new port
number directly into the drop-down box. If the port number you choose
is in use, you are prompted to confirm your choice of port number.

Set the `Server SQL Mode' to either enable or disable strict mode.
Enabling strict mode (default) makes MySQL behave more like other
database management systems. _If you run applications that rely on
MySQL's old `forgiving' behavior, make sure to either adapt those
applications or to disable strict mode._ For more information about
strict mode, see *Note server-sql-mode::.


File: manual.info,  Node: mysql-config-wizard-character-set,  Next: mysql-config-wizard-service,  Prev: mysql-config-wizard-networking,  Up: mysql-config-wizard

3.10.3.9 The Character Set Dialog
.................................

The MySQL server supports multiple character sets and it is possible to
set a default server character set that is applied to all tables,
columns, and databases unless overridden. Use the `Character Set'
dialog to change the default character set of the MySQL server.

MySQL Server Instance Configuration Wizard: Character Set

   * `Standard Character Set': Choose this option if you want to use
     `latin1' as the default server character set. `latin1' is used for
     English and many Western European languages.

   * `Best Support For Multilingualism': Choose this option if you want
     to use `utf8' as the default server character set.  This is a
     Unicode character set that can store characters from many
     different languages.

   * `Manual Selected Default Character Set / Collation': Choose this
     option if you want to pick the server's default character set
     manually. Choose the desired character set from the provided
     drop-down list.


File: manual.info,  Node: mysql-config-wizard-service,  Next: mysql-config-wizard-security,  Prev: mysql-config-wizard-character-set,  Up: mysql-config-wizard

3.10.3.10 The Service Options Dialog
....................................

On Windows platforms, the MySQL server can be installed as a Windows
service. When installed this way, the MySQL server can be started
automatically during system startup, and even restarted automatically
by Windows in the event of a service failure.

The MySQL Server Instance Configuration Wizard installs the MySQL
server as a service by default, using the service name `MySQL'. If you
do not wish to install the service, uncheck the box next to the
`Install As Windows Service' option. You can change the service name by
picking a new service name from the drop-down box provided or by
entering a new service name into the drop-down box.

*Note*:

Service names can include any legal character except forward (`/') or
backward (`\') slashes, and must be less than 256 characters long.

*Warning*:

If you are installing multiple versions of MySQL onto the same machine,
you _must_ choose a different service name for each version that you
install. If you do not choose a different service for each installed
version then the service manager information will be inconsistent and
this will cause problems when you try to uninstall a previous version.

If you have already installed multiple versions using the same service
name, you must manually edit the contents of the
`HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services' parameters
within the Windows registry to update the association of the service
name with the correct server version.

Typically, when installing multiple versions you create a service name
based on the version information. For example, you might install MySQL
5.x as `mysql5', or specific versions such as MySQL 5.0.56 as
`mysql50056'.

To install the MySQL server as a service but not have it started
automatically at startup, uncheck the box next to the `Launch the MySQL
Server Automatically' option.


File: manual.info,  Node: mysql-config-wizard-security,  Next: mysql-config-wizard-confirmation,  Prev: mysql-config-wizard-service,  Up: mysql-config-wizard

3.10.3.11 The Security Options Dialog
.....................................

_It is strongly recommended that you set a `root' password for your
MySQL server_, and the MySQL Server Instance Configuration Wizard
requires by default that you do so. If you do not wish to set a `root'
password, uncheck the box next to the `Modify Security Settings' option.

MySQL Server Instance Configuration Wizard: Security

To set the `root' password, enter the desired password into both the
`New root password' and `Confirm' boxes. If you are reconfiguring an
existing server, you need to enter the existing `root' password into the
`Current root password' box.

To permit `root' logins from across the network, check the box next to
the `Enable root access from remote machines' option. This decreases
the security of your `root' account.

To create an anonymous user account, check the box next to the `Create
An Anonymous Account' option.  Creating an anonymous account can
decrease server security and cause login and permission difficulties.
For this reason, it is not recommended.


File: manual.info,  Node: mysql-config-wizard-confirmation,  Prev: mysql-config-wizard-security,  Up: mysql-config-wizard

3.10.3.12 The Confirmation Dialog
.................................

The final dialog in the MySQL Server Instance Configuration Wizard is
the `Confirmation Dialog'. To start the configuration process, click the
`Execute' button. To return to a previous dialog, click the `Back'
button. To exit the MySQL Server Instance Configuration Wizard without
configuring the server, click the `Cancel' button.

MySQL Server Instance Configuration Wizard: Confirmation

After you click the `Execute' button, the MySQL Server Instance
Configuration Wizard performs a series of tasks and displays the
progress onscreen as the tasks are performed.

The MySQL Server Instance Configuration Wizard first determines
configuration file options based on your choices using a template
prepared by MySQL developers and engineers. This template is named
`my-template.ini' and is located in your server installation directory.

The MySQL Configuration Wizard then writes these options to the
corresponding configuration file.

If you chose to create a service for the MySQL server, the MySQL Server
Instance Configuration Wizard creates and starts the service. If you
are reconfiguring an existing service, the MySQL Server Instance
Configuration Wizard restarts the service to apply your configuration
changes.

If you chose to set a `root' password, the MySQL Configuration Wizard
connects to the server, sets your new `root' password, and applies any
other security settings you may have selected.

After the MySQL Server Instance Configuration Wizard has completed its
tasks, it displays a summary. Click the `Finish' button to exit the
MySQL Server Configuration Wizard.


File: manual.info,  Node: windows-install-archive,  Next: windows-troubleshooting,  Prev: mysql-config-wizard,  Up: windows-installation

3.10.4 Installing MySQL on Microsoft Windows Using a `noinstall' Zip Archive
----------------------------------------------------------------------------

* Menu:

* windows-extract-archive::      Extracting the Install Archive
* windows-create-option-file::   Creating an Option File
* windows-select-server::        Selecting a MySQL Server Type
* windows-server-first-start::   Starting the Server for the First Time
* windows-start-command-line::   Starting MySQL from the Windows Command Line
* mysql-installation-windows-path::  Customizing the PATH for MySQL Tools
* windows-start-service::        Starting MySQL as a Windows Service
* windows-testing::              Testing The MySQL Installation

Users who are installing from the Noinstall package can use the
instructions in this section to manually install MySQL. The process for
installing MySQL from a Zip archive is as follows:

  1. Extract the archive to the desired install directory

  2. Create an option file

  3. Choose a MySQL server type

  4. Start the MySQL server

  5. Secure the default user accounts

This process is described in the sections that follow.


File: manual.info,  Node: windows-extract-archive,  Next: windows-create-option-file,  Prev: windows-install-archive,  Up: windows-install-archive

3.10.4.1 Extracting the Install Archive
.......................................

To install MySQL manually, do the following:

  1. If you are upgrading from a previous version please refer to *Note
     windows-upgrading::, before beginning the upgrade process.

  2. Make sure that you are logged in as a user with administrator
     privileges.

  3. Choose an installation location. Traditionally, the MySQL server
     is installed in `C:\mysql'. The MySQL Installation Wizard installs
     MySQL under `C:\Program Files\MySQL'. If you do not install MySQL
     at `C:\mysql', you must specify the path to the install directory
     during startup or in an option file. See *Note
     windows-create-option-file::.

  4. Extract the install archive to the chosen installation location
     using your preferred Zip archive tool. Some tools may extract the
     archive to a folder within your chosen installation location. If
     this occurs, you can move the contents of the subfolder into the
     chosen installation location.


File: manual.info,  Node: windows-create-option-file,  Next: windows-select-server,  Prev: windows-extract-archive,  Up: windows-install-archive

3.10.4.2 Creating an Option File
................................

If you need to specify startup options when you run the server, you can
indicate them on the command line or place them in an option file. For
options that are used every time the server starts, you may find it
most convenient to use an option file to specify your MySQL
configuration. This is particularly true under the following
circumstances:

   * The installation or data directory locations are different from
     the default locations (`C:\Program Files\MySQL\MySQL Server 5.0'
     and `C:\Program Files\MySQL\MySQL Server 5.0\data').

   * You need to tune the server settings.

When the MySQL server starts on Windows, it looks for option files in
several locations, such as the Windows directory, `C:\', and the MySQL
installation directory (for the full list of locations, see *Note
option-files::). The Windows directory typically is named something
like `C:\WINDOWS'. You can determine its exact location from the value
of the `WINDIR' environment variable using the following command:

     shell> echo %WINDIR%

MySQL looks for options in each location first in the `my.ini' file,
and then in the `my.cnf' file. However, to avoid confusion, it is best
if you use only one file. If your PC uses a boot loader where `C:' is
not the boot drive, your only option is to use the `my.ini' file.
Whichever option file you use, it must be a plain text file.

You can also make use of the example option files included with your
MySQL distribution; see *Note option-files-preconfigured::.

An option file can be created and modified with any text editor, such
as Notepad. For example, if MySQL is installed in `E:\mysql' and the
data directory is in `E:\mydata\data', you can create an option file
containing a `[mysqld]' section to specify values for the `basedir' and
`datadir' options:

     [mysqld]
     # set basedir to your installation path
     basedir=E:/mysql
     # set datadir to the location of your data directory
     datadir=E:/mydata/data

Note that Windows path names are specified in option files using
(forward) slashes rather than backslashes. If you do use backslashes,
double them:

     [mysqld]
     # set basedir to your installation path
     basedir=E:\\mysql
     # set datadir to the location of your data directory
     datadir=E:\\mydata\\data

The rules for use of backslash in option file values are given in *Note
option-files::.

On Windows, the MySQL installer places the data directory directly
under the directory where you install MySQL. If you would like to use a
data directory in a different location, you should copy the entire
contents of the `data' directory to the new location. For example, if
MySQL is installed in `C:\Program Files\MySQL\MySQL Server 5.0', the
data directory is by default in `C:\Program Files\MySQL\MySQL Server
5.0\data'. If you want to use `E:\mydata' as the data directory instead,
you must do two things:

  1. Move the entire `data' directory and all of its contents from
     `C:\Program Files\MySQL\MySQL Server 5.0\data' to `E:\mydata'.

  2. Use a `--datadir' option to specify the new data directory
     location each time you start the server.


File: manual.info,  Node: windows-select-server,  Next: windows-server-first-start,  Prev: windows-create-option-file,  Up: windows-install-archive

3.10.4.3 Selecting a MySQL Server Type
......................................

The following table shows the available servers for Windows in MySQL
5.0.

Binary         Description
*Note          Optimized binary with named-pipe support
`mysqld-nt':   
mysqld.        
*Note          Optimized binary without named-pipe support
`mysqld':      
mysqld.        
*Note          Like *Note `mysqld-nt': mysqld, but compiled with full
`mysqld-debug':debugging and automatic memory allocation checking
mysqld.        

All of the preceding binaries are optimized for modern Intel
processors, but should work on any Intel i386-class or higher processor.

Each of the servers in a distribution support the same set of storage
engines. The *Note `SHOW ENGINES': show-engines.  statement displays
which engines a given server supports.

All Windows MySQL 5.0 servers have support for symbolic linking of
database directories.

MySQL supports TCP/IP on all Windows platforms. MySQL servers on
Windows support named pipes as indicated in the following list.
However, the default is to use TCP/IP regardless of platform.  (Named
pipes are slower than TCP/IP in many Windows configurations.)

Use of named pipes is subject to these conditions:

   * Named pipes are enabled only if you start the server with the
     `--enable-named-pipe' option. It is necessary to use this option
     explicitly because some users have experienced problems with
     shutting down the MySQL server when named pipes were used.

   * Named-pipe connections are permitted only by the *Note
     `mysqld-nt': mysqld. and *Note `mysqld-debug': mysqld. servers.

*Note*:

Most of the examples in this manual use *Note `mysqld': mysqld. as the
server name. If you choose to use a different server, such as *Note
`mysqld-nt': mysqld, make the appropriate substitutions in the commands
that are shown in the examples.


File: manual.info,  Node: windows-server-first-start,  Next: windows-start-command-line,  Prev: windows-select-server,  Up: windows-install-archive

3.10.4.4 Starting the Server for the First Time
...............................................

This section gives a general overview of starting the MySQL server. The
following sections provide more specific information for starting the
MySQL server from the command line or as a Windows service.

The information here applies primarily if you installed MySQL using the
`Noinstall' version, or if you wish to configure and test MySQL
manually rather than with the GUI tools.

The examples in these sections assume that MySQL is installed under the
default location of `C:\Program Files\MySQL\MySQL Server 5.0'. Adjust
the path names shown in the examples if you have MySQL installed in a
different location.

Clients have two options. They can use TCP/IP, or they can use a named
pipe if the server supports named-pipe connections.

MySQL for Windows also supports shared-memory connections if the server
is started with the `--shared-memory' option. Clients can connect
through shared memory by using the `--protocol=MEMORY' option.

For information about which server binary to run, see *Note
windows-select-server::.

Testing is best done from a command prompt in a console window (or `DOS
window'). In this way you can have the server display status messages
in the window where they are easy to see. If something is wrong with
your configuration, these messages make it easier for you to identify
and fix any problems.

To start the server, enter this command:

     shell> "C:\Program Files\MySQL\MySQL Server 5.0\bin\mysqld" --console

For a server that includes `InnoDB' support, you should see the
messages similar to those following as it starts (the path names and
sizes may differ):

     InnoDB: The first specified datafile c:\ibdata\ibdata1 did not exist:
     InnoDB: a new database to be created!
     InnoDB: Setting file c:\ibdata\ibdata1 size to 209715200
     InnoDB: Database physically writes the file full: wait...
     InnoDB: Log file c:\iblogs\ib_logfile0 did not exist: new to be created
     InnoDB: Setting log file c:\iblogs\ib_logfile0 size to 31457280
     InnoDB: Log file c:\iblogs\ib_logfile1 did not exist: new to be created
     InnoDB: Setting log file c:\iblogs\ib_logfile1 size to 31457280
     InnoDB: Log file c:\iblogs\ib_logfile2 did not exist: new to be created
     InnoDB: Setting log file c:\iblogs\ib_logfile2 size to 31457280
     InnoDB: Doublewrite buffer not found: creating new
     InnoDB: Doublewrite buffer created
     InnoDB: creating foreign key constraint system tables
     InnoDB: foreign key constraint system tables created
     011024 10:58:25  InnoDB: Started

When the server finishes its startup sequence, you should see something
like this, which indicates that the server is ready to service client
connections:

     mysqld: ready for connections
     Version: '5.0.95'  socket: ''  port: 3306

The server continues to write to the console any further diagnostic
output it produces. You can open a new console window in which to run
client programs.

If you omit the `--console' option, the server writes diagnostic output
to the error log in the data directory (`C:\Program Files\MySQL\MySQL
Server 5.0\data' by default). The error log is the file with the `.err'
extension.

*Note*:

The accounts that are listed in the MySQL grant tables initially have
no passwords. After starting the server, you should set up passwords
for them using the instructions in *Note postinstallation::.


File: manual.info,  Node: windows-start-command-line,  Next: mysql-installation-windows-path,  Prev: windows-server-first-start,  Up: windows-install-archive

3.10.4.5 Starting MySQL from the Windows Command Line
.....................................................

The MySQL server can be started manually from the command line.  This
can be done on any version of Windows.

To start the *Note `mysqld': mysqld. server from the command line, you
should start a console window (or `DOS window') and enter this command:

     shell> "C:\Program Files\MySQL\MySQL Server 5.0\bin\mysqld"

The path to *Note `mysqld': mysqld. may vary depending on the install
location of MySQL on your system.

You can stop the MySQL server by executing this command:

     shell> "C:\Program Files\MySQL\MySQL Server 5.0\bin\mysqladmin" -u root shutdown

*Note*:

If the MySQL `root' user account has a password, you need to invoke
*Note `mysqladmin': mysqladmin.  with the `-p' option and supply the
password when prompted.

This command invokes the MySQL administrative utility *Note
`mysqladmin': mysqladmin. to connect to the server and tell it to shut
down. The command connects as the MySQL `root' user, which is the
default administrative account in the MySQL grant system. Note that
users in the MySQL grant system are wholly independent from any login
users under Windows.

If *Note `mysqld': mysqld. doesn't start, check the error log to see
whether the server wrote any messages there to indicate the cause of
the problem. The error log is located in the `C:\Program
Files\MySQL\MySQL Server 5.0\data' directory. It is the file with a
suffix of `.err'. You can also try to start the server as *Note `mysqld
--console': mysqld.; in this case, you may get some useful information
on the screen that may help solve the problem.

The last option is to start *Note `mysqld': mysqld. with the
`--standalone' and `--debug' options. In this case, *Note `mysqld':
mysqld. writes a log file `C:\mysqld.trace' that should contain the
reason why *Note `mysqld': mysqld. doesn't start. See MySQL Internals:
Porting (http://forge.mysql.com/wiki/MySQL_Internals_Porting).

Use *Note `mysqld --verbose --help': mysqld. to display all the options
that *Note `mysqld': mysqld. supports.


File: manual.info,  Node: mysql-installation-windows-path,  Next: windows-start-service,  Prev: windows-start-command-line,  Up: windows-install-archive

3.10.4.6 Customizing the PATH for MySQL Tools
.............................................

To make it easier to invoke MySQL programs, you can add the path name
of the MySQL `bin' directory to your Windows system `PATH' environment
variable:

   * On the Windows desktop, right-click the `My Computer' icon, and
     select `Properties'.

   * Next select the `Advanced' tab from the `System Properties' menu
     that appears, and click the `Environment Variables' button.

   * Under `System Variables', select `Path', and then click the `Edit'
     button. The `Edit System Variable' dialogue should appear.

   * Place your cursor at the end of the text appearing in the space
     marked `Variable Value'. (Use the `End' key to ensure that your
     cursor is positioned at the very end of the text in this space.)
     Then enter the complete path name of your MySQL `bin' directory
     (for example, `C:\Program Files\MySQL\MySQL Server 5.0\bin')

     *Note*:

     There must be a semicolon separating this path from any values
     present in this field.

     Dismiss this dialogue, and each dialogue in turn, by clicking `OK'
     until all of the dialogues that were opened have been dismissed.
     You should now be able to invoke any MySQL executable program by
     typing its name at the DOS prompt from any directory on the system,
     without having to supply the path. This includes the servers, the
     *Note `mysql': mysql. client, and all MySQL command-line utilities
     such as *Note `mysqladmin': mysqladmin.  and *Note `mysqldump':
     mysqldump.

     You should not add the MySQL `bin' directory to your Windows
     `PATH' if you are running multiple MySQL servers on the same
     machine.

*Warning*:

You must exercise great care when editing your system `PATH' by hand;
accidental deletion or modification of any portion of the existing
`PATH' value can leave you with a malfunctioning or even unusable
system.


File: manual.info,  Node: windows-start-service,  Next: windows-testing,  Prev: mysql-installation-windows-path,  Up: windows-install-archive

3.10.4.7 Starting MySQL as a Windows Service
............................................

On Windows, the recommended way to run MySQL is to install it as a
Windows service, whereby MySQL starts and stops automatically when
Windows starts and stops. A MySQL server installed as a service can
also be controlled from the command line using `NET' commands, or with
the graphical `Services' utility. Generally, to install MySQL as a
Windows service you should be logged in using an account that has
administrator rights.

The `Services' utility (the Windows `Service Control Manager') can be
found in the Windows Control Panel (under `Administrative Tools' on
Windows 2000, XP, Vista, and Server 2003). To avoid conflicts, it is
advisable to close the `Services' utility while performing server
installation or removal operations from the command line.

Before installing MySQL as a Windows service, you should first stop the
current server if it is running by using the following command:

     shell> "C:\Program Files\MySQL\MySQL Server 5.0\bin\mysqladmin"
               -u root shutdown

*Note*:

If the MySQL `root' user account has a password, you need to invoke
*Note `mysqladmin': mysqladmin.  with the `-p' option and supply the
password when prompted.

This command invokes the MySQL administrative utility *Note
`mysqladmin': mysqladmin. to connect to the server and tell it to shut
down. The command connects as the MySQL `root' user, which is the
default administrative account in the MySQL grant system. Note that
users in the MySQL grant system are wholly independent from any login
users under Windows.

Install the server as a service using this command:

     shell> "C:\Program Files\MySQL\MySQL Server 5.0\bin\mysqld" --install

The service-installation command does not start the server.
Instructions for that are given later in this section.

To make it easier to invoke MySQL programs, you can add the path name
of the MySQL `bin' directory to your Windows system `PATH' environment
variable:

   * On the Windows desktop, right-click the `My Computer' icon, and
     select `Properties'.

   * Next select the `Advanced' tab from the `System Properties' menu
     that appears, and click the `Environment Variables' button.

   * Under `System Variables', select `Path', and then click the `Edit'
     button. The `Edit System Variable' dialogue should appear.

   * Place your cursor at the end of the text appearing in the space
     marked `Variable Value'. (Use the `End' key to ensure that your
     cursor is positioned at the very end of the text in this space.)
     Then enter the complete path name of your MySQL `bin' directory
     (for example, `C:\Program Files\MySQL\MySQL Server 5.0\bin'), Note
     that there should be a semicolon separating this path from any
     values present in this field. Dismiss this dialogue, and each
     dialogue in turn, by clicking `OK' until all of the dialogues that
     were opened have been dismissed. You should now be able to invoke
     any MySQL executable program by typing its name at the DOS prompt
     from any directory on the system, without having to supply the
     path. This includes the servers, the *Note `mysql': mysql. client,
     and all MySQL command-line utilities such as *Note `mysqladmin':
     mysqladmin.  and *Note `mysqldump': mysqldump.

     You should not add the MySQL `bin' directory to your Windows
     `PATH' if you are running multiple MySQL servers on the same
     machine.

*Warning*:

You must exercise great care when editing your system `PATH' by hand;
accidental deletion or modification of any portion of the existing
`PATH' value can leave you with a malfunctioning or even unusable
system.

The following additional arguments can be used when installing the
service:

   * You can specify a service name immediately following the
     `--install' option. The default service name is `MySQL'.

   * If a service name is given, it can be followed by a single option.
     By convention, this should be `--defaults-file=FILE_NAME' to
     specify the name of an option file from which the server should
     read options when it starts.

     The use of a single option other than `--defaults-file' is possible
     but discouraged.  `--defaults-file' is more flexible because it
     enables you to specify multiple startup options for the server by
     placing them in the named option file. Also, in MySQL 5.0, use of
     an option different from `--defaults-file' is not supported until
     5.0.3.

   * As of MySQL 5.0.1, you can also specify a `--local-service' option
     following the service name. This causes the server to run using the
     `LocalService' Windows account that has limited system privileges.
     This account is available only for Windows XP or newer. If both
     `--defaults-file' and `--local-service' are given following the
     service name, they can be in any order.

For a MySQL server that is installed as a Windows service, the
following rules determine the service name and option files that the
server uses:

   * If the service-installation command specifies no service name or
     the default service name (`MySQL') following the `--install'
     option, the server uses the a service name of `MySQL' and reads
     options from the `[mysqld]' group in the standard option files.

   * If the service-installation command specifies a service name other
     than `MySQL' following the `--install' option, the server uses that
     service name. It reads options from the `[mysqld]' group and the
     group that has the same name as the service in the standard option
     files. This enables you to use the `[mysqld]' group for options
     that should be used by all MySQL services, and an option group
     with the service name for use by the server installed with that
     service name.

   * If the service-installation command specifies a `--defaults-file'
     option after the service name, the server reads options only from
     the `[mysqld]' group of the named file and ignores the standard
     option files.

As a more complex example, consider the following command:

     shell> "C:\Program Files\MySQL\MySQL Server 5.0\bin\mysqld"
               --install MySQL --defaults-file=C:\my-opts.cnf

Here, the default service name (`MySQL') is given after the `--install'
option. If no `--defaults-file' option had been given, this command
would have the effect of causing the server to read the `[mysqld]'
group from the standard option files. However, because the
`--defaults-file' option is present, the server reads options from the
`[mysqld]' option group, and only from the named file.

You can also specify options as Start parameters in the Windows
`Services' utility before you start the MySQL service.

Once a MySQL server has been installed as a service, Windows starts the
service automatically whenever Windows starts. The service also can be
started immediately from the `Services' utility, or by using a `NET
START MySQL' command. The `NET' command is not case sensitive.

When run as a service, *Note `mysqld': mysqld. has no access to a
console window, so no messages can be seen there. If *Note `mysqld':
mysqld. does not start, check the error log to see whether the server
wrote any messages there to indicate the cause of the problem. The
error log is located in the MySQL data directory (for example,
`C:\Program Files\MySQL\MySQL Server 5.0\data'). It is the file with a
suffix of `.err'.

When a MySQL server has been installed as a service, and the service is
running, Windows stops the service automatically when Windows shuts
down. The server also can be stopped manually by using the `Services'
utility, the `NET STOP MySQL' command, or the *Note `mysqladmin
shutdown': mysqladmin. command.

You also have the choice of installing the server as a manual service
if you do not wish for the service to be started automatically during
the boot process. To do this, use the `--install-manual' option rather
than the `--install' option:

     shell> "C:\Program Files\MySQL\MySQL Server 5.0\bin\mysqld" --install-manual

To remove a server that is installed as a service, first stop it if it
is running by executing `NET STOP MySQL'.  Then use the `--remove'
option to remove it:

     shell> "C:\Program Files\MySQL\MySQL Server 5.0\bin\mysqld" --remove

If *Note `mysqld': mysqld. is not running as a service, you can start
it from the command line. For instructions, see *Note
windows-start-command-line::.

Please see *Note windows-troubleshooting::, if you encounter
difficulties during installation.


File: manual.info,  Node: windows-testing,  Prev: windows-start-service,  Up: windows-install-archive

3.10.4.8 Testing The MySQL Installation
.......................................

You can test whether the MySQL server is working by executing any of
the following commands:

     shell> "C:\Program Files\MySQL\MySQL Server 5.0\bin\mysqlshow"
     shell> "C:\Program Files\MySQL\MySQL Server 5.0\bin\mysqlshow" -u root mysql
     shell> "C:\Program Files\MySQL\MySQL Server 5.0\bin\mysqladmin" version status proc
     shell> "C:\Program Files\MySQL\MySQL Server 5.0\bin\mysql" test

If *Note `mysqld': mysqld. is slow to respond to TCP/IP connections
from client programs, there is probably a problem with your DNS. In
this case, start *Note `mysqld': mysqld.  with the `--skip-name-resolve'
option and use only `localhost' and IP addresses in the `Host' column
of the MySQL grant tables.

You can force a MySQL client to use a named-pipe connection rather than
TCP/IP by specifying the `--pipe' or `--protocol=PIPE' option, or by
specifying `.' (period) as the host name. Use the `--socket' option to
specify the name of the pipe if you do not want to use the default pipe
name.

Note that if you have set a password for the `root' account, deleted
the anonymous account, or created a new user account, then you must use
the appropriate `-u' and `-p' options with the commands shown above to
connect with the MySQL Server. See *Note connecting::.

For more information about *Note `mysqlshow': mysqlshow, see *Note
mysqlshow::.


File: manual.info,  Node: windows-troubleshooting,  Next: windows-upgrading,  Prev: windows-install-archive,  Up: windows-installation

3.10.5 Troubleshooting a MySQL Installation Under Windows
---------------------------------------------------------

When installing and running MySQL for the first time, you may encounter
certain errors that prevent the MySQL server from starting. The purpose
of this section is to help you diagnose and correct some of these
errors.

Your first resource when troubleshooting server issues is the error
log. The MySQL server uses the error log to record information relevant
to the error that prevents the server from starting. The error log is
located in the data directory specified in your `my.ini' file. The
default data directory location is `C:\Program Files\MySQL\MySQL Server
5.0\data'. See *Note error-log::.

Another source of information regarding possible errors is the console
messages displayed when the MySQL service is starting. Use the `NET
START MySQL' command from the command line after installing *Note
`mysqld': mysqld. as a service to see any error messages regarding the
starting of the MySQL server as a service. See *Note
windows-start-service::.

The following examples show other common error messages you may
encounter when installing MySQL and starting the server for the first
time:

   * If the MySQL server cannot find the `mysql' privileges database or
     other critical files, you may see these messages:

          System error 1067 has occurred.
          Fatal error: Can't open privilege tables: Table 'mysql.host' doesn't exist

     These messages often occur when the MySQL base or data directories
     are installed in different locations than the default locations
     (`C:\Program Files\MySQL\MySQL Server 5.0' and `C:\Program
     Files\MySQL\MySQL Server 5.0\data', respectively).

     This situation may occur when MySQL is upgraded and installed to a
     new location, but the configuration file is not updated to reflect
     the new location. In addition, there may be old and new
     configuration files that conflict. Be sure to delete or rename any
     old configuration files when upgrading MySQL.

     If you have installed MySQL to a directory other than `C:\Program
     Files\MySQL\MySQL Server 5.0', you need to ensure that the MySQL
     server is aware of this through the use of a configuration
     (`my.ini') file. The `my.ini' file needs to be located in your
     Windows directory, typically `C:\WINDOWS'.  You can determine its
     exact location from the value of the `WINDIR' environment variable
     by issuing the following command from the command prompt:

          shell> echo %WINDIR%

     An option file can be created and modified with any text editor,
     such as Notepad. For example, if MySQL is installed in `E:\mysql'
     and the data directory is `D:\MySQLdata', you can create the option
     file and set up a `[mysqld]' section to specify values for the
     `basedir' and `datadir' options:

          [mysqld]
          # set basedir to your installation path
          basedir=E:/mysql
          # set datadir to the location of your data directory
          datadir=D:/MySQLdata

     Note that Windows path names are specified in option files using
     (forward) slashes rather than backslashes. If you do use
     backslashes, double them:

          [mysqld]
          # set basedir to your installation path
          basedir=C:\\Program Files\\MySQL\\MySQL Server 5.0
          # set datadir to the location of your data directory
          datadir=D:\\MySQLdata

     The rules for use of backslash in option file values are given in
     *Note option-files::.

     If you change the `datadir' value in your MySQL configuration
     file, you must move the contents of the existing MySQL data
     directory before restarting the MySQL server.

     See *Note windows-create-option-file::.

   * If you reinstall or upgrade MySQL without first stopping and
     removing the existing MySQL service and install MySQL using the
     MySQL Configuration Wizard, you may see this error:

          Error: Cannot create Windows service for MySql. Error: 0

     This occurs when the Configuration Wizard tries to install the
     service and finds an existing service with the same name.

     One solution to this problem is to choose a service name other
     than `mysql' when using the configuration wizard. This enables the
     new service to be installed correctly, but leaves the outdated
     service in place. Although this is harmless, it is best to remove
     old services that are no longer in use.

     To permanently remove the old `mysql' service, execute the
     following command as a user with administrative privileges, on the
     command-line:

          shell> sc delete mysql
          [SC] DeleteService SUCCESS

     If the `sc' utility is not available for your version of Windows,
     download the `delsrv' utility from
     `http://www.microsoft.com/windows2000/techinfo/reskit/tools/existing/delsrv-o.asp'
     and use the `delsrv mysql' syntax.


File: manual.info,  Node: windows-upgrading,  Next: windows-postinstallation,  Prev: windows-troubleshooting,  Up: windows-installation

3.10.6 Upgrading MySQL on Windows
---------------------------------

This section lists some of the steps you should take when upgrading
MySQL on Windows.

  1. Review *Note upgrading::, for additional information on upgrading
     MySQL that is not specific to Windows.

  2. You should always back up your current MySQL installation before
     performing an upgrade. See *Note backup-methods::.

  3. Download the latest Windows distribution of MySQL from
     `http://dev.mysql.com/downloads/'.

  4. Before upgrading MySQL, you must stop the server. If the server is
     installed as a service, stop the service with the following
     command from the command prompt:

          shell> NET STOP MySQL

     If you are not running the MySQL server as a service, use *Note
     `mysqladmin': mysqladmin. to stop it. For example, before
     upgrading from MySQL 4.1 to 5.0, use *Note `mysqladmin':
     mysqladmin. from MySQL 4.1 as follows:

          shell> "C:\Program Files\MySQL\MySQL Server 4.1\bin\mysqladmin" -u root shutdown

     *Note*:

     If the MySQL `root' user account has a password, you need to
     invoke *Note `mysqladmin': mysqladmin.  with the `-p' option and
     supply the password when prompted.

  5. Before upgrading to MySQL 5.0 from a version previous to 4.1.5, or
     from a version of MySQL installed from a Zip archive to a version
     of MySQL installed with the MySQL Installation Wizard, you must
     first manually remove the previous installation and MySQL service
     (if the server is installed as a service).

     To remove the MySQL service, use the following command:

          shell> C:\mysql\bin\mysqld --remove

     *If you do not remove the existing service, the MySQL Installation
     Wizard may fail to properly install the new MySQL service.*

  6. If you are using the MySQL Installation Wizard, start the wizard
     as described in *Note windows-install-wizard::.

  7. If you are installing MySQL from a Zip archive, extract the
     archive. You may either overwrite your existing MySQL installation
     (usually located at `C:\mysql'), or install it into a different
     directory, such as `C:\mysql5'. Overwriting the existing
     installation is recommended.

  8. If you were running MySQL as a Windows service and you had to
     remove the service earlier in this procedure, reinstall the
     service. (See *Note windows-start-service::.)

  9. Restart the server. For example, use `NET START MySQL' if you run
     MySQL as a service, or invoke *Note `mysqld': mysqld. directly
     otherwise.

 10. As Administrator, run *Note `mysql_upgrade': mysql-upgrade. to
     check your tables, attempt to repair them if necessary, and update
     your grant tables if they have changed so that you can take
     advantage of any new capabilities. See *Note mysql-upgrade::.

 11. If you encounter errors, see *Note windows-troubleshooting::.


File: manual.info,  Node: windows-postinstallation,  Next: windows-source-build,  Prev: windows-upgrading,  Up: windows-installation

3.10.7 Windows Postinstallation Procedures
------------------------------------------

On Windows, you need not create the data directory and the grant
tables. MySQL Windows distributions include the grant tables with a set
of preinitialized accounts in the `mysql' database under the data
directory. Regarding passwords, if you installed MySQL using the
Windows Installation Wizard, you may have already assigned passwords to
the accounts. (See *Note windows-install-wizard::.) Otherwise, use the
password-assignment procedure given in *Note default-privileges::.

Before setting up passwords, you might want to try running some client
programs to make sure that you can connect to the server and that it is
operating properly. Make sure that the server is running (see *Note
windows-server-first-start::), and then issue the following commands to
verify that you can retrieve information from the server. You may need
to specify directory different from `C:\mysql\bin' on the command line.
If you used the Windows Installation Wizard, the default directory is
`C:\Program Files\MySQL\MySQL Server 5.0', and the *Note `mysql':
mysql. and *Note `mysqlshow': mysqlshow. client programs are in
`C:\Program Files\MySQL\MySQL Server 5.0\bin'. See *Note
windows-install-wizard::, for more information.

Use *Note `mysqlshow': mysqlshow. to see what databases exist:

     C:\> C:\mysql\bin\mysqlshow
     +--------------------+
     |     Databases      |
     +--------------------+
     | information_schema |
     | mysql              |
     | test               |
     +--------------------+

The list of installed databases may vary, but will always include the
minimum of `mysql' and `information_schema'. In most cases, the `test'
database will also be installed automatically.

The preceding command (and commands for other MySQL programs such as
*Note `mysql': mysql.) may not work if the correct MySQL account does
not exist. For example, the program may fail with an error, or you may
not be able to view all databases. If you installed using the MSI
packages and used the MySQL Server Instance Config Wizard, then the
`root' user will have been created automatically with the password you
supplied. In this case, you should use the `-u root' and `-p' options.
(You will also need to use the `-u root' and `-p' options if you have
already secured the initial MySQL accounts.) With `-p', you will be
prompted for the `root' password. For example:

     C:\> C:\mysql\bin\mysqlshow -u root -p
     Enter password: (ENTER ROOT PASSWORD HERE)
     +--------------------+
     |     Databases      |
     +--------------------+
     | information_schema |
     | mysql              |
     | test               |
     +--------------------+

If you specify a database name, *Note `mysqlshow': mysqlshow.  displays
a list of the tables within the database:

     C:\> C:\mysql\bin\mysqlshow mysql
     Database: mysql
     +---------------------------+
     |          Tables           |
     +---------------------------+
     | columns_priv              |
     | db                        |
     | func                      |
     | help_category             |
     | help_keyword              |
     | help_relation             |
     | help_topic                |
     | host                      |
     | proc                      |
     | procs_priv                |
     | tables_priv               |
     | time_zone                 |
     | time_zone_leap_second     |
     | time_zone_name            |
     | time_zone_transition      |
     | time_zone_transition_type |
     | user                      |
     +---------------------------+

Use the *Note `mysql': mysql. program to select information from a
table in the `mysql' database:

     C:\> C:\mysql\bin\mysql -e "SELECT Host,Db,User FROM mysql.db"
     +------+--------+------+
     | host | db     | user |
     +------+--------+------+
     | %    | test   |      |
     | %    | test_% |      |
     +------+--------+------+

For more information about *Note `mysqlshow': mysqlshow. and *Note
`mysql': mysql, see *Note mysqlshow::, and *Note mysql::.

If you are running a version of Windows that supports services, you can
set up the MySQL server to run automatically when Windows starts. See
*Note windows-start-service::.


File: manual.info,  Node: windows-source-build,  Prev: windows-postinstallation,  Up: windows-installation

3.10.8 Installing MySQL from Source on Windows
----------------------------------------------

* Menu:

* windows-source-build-cmake::   Building MySQL from the Standard Source Distribution
* windows-vc-plus-plus-build::   Building MySQL from a Windows Source Distribution
* windows-source-install::       Installing MySQL from a Source Build on Windows
* windows-source-testbuild::     Testing a Windows Source Build
* windows-sourcetree-build::     Creating a Windows Source Package from the Bazaar Repository

These instructions describe how to build binaries from source for MySQL
5.0 on Windows. Instructions are provided for building binaries from a
standard source distribution or from the Bazaar tree that contains the
latest development source.

*Note*:

The instructions here are strictly for users who want to test MySQL on
Microsoft Windows from the latest source distribution or from the
Bazaar tree. For production use, we do not advise using a MySQL server
built by yourself from source. Normally, it is best to use precompiled
binary distributions of MySQL that are built specifically for optimal
performance on Windows by Oracle Corporation. Instructions for
installing binary distributions are available in *Note
windows-installation::.

To build MySQL on Windows from source, you must satisfy the following
system, compiler, and resource requirements:

   * Windows 2000, Windows XP, or newer version.

     Windows Vista is supported when using Visual Studio 2005 provided
     you have installed the following updates:

        * Microsoft Visual Studio 2005 Professional Edition - ENU
          Service Pack 1 (KB926601)
          (http://support.microsoft.com/?kbid=926601)

        * Security Update for Microsoft Visual Studio 2005 Professional
          Edition - ENU (KB937061)
          (http://support.microsoft.com/?kbid=937061)

        * Update for Microsoft Visual Studio 2005 Professional Edition
          - ENU (KB932232) (http://support.microsoft.com/?kbid=932232)

   * To build from the standard source distribution, you will need
     `CMake', which can be downloaded from `http://www.cmake.org'.
     After installing, modify your `PATH' environment variable to
     include the directory where `cmake' is located.

   * Microsoft Visual C++ 2005 Express Edition, Visual Studio .Net 2003
     (7.1), or Visual Studio 2005 (8.0) compiler system.

   * If you are using Visual C++ 2005 Express Edition, you must also
     install an appropriate Platform SDK. More information and links to
     downloads for various Windows platforms is available from
     `http://www.microsoft.com/downloads/details.aspx?familyid=0baf2b35-c656-4969-ace8-e4c0c0716adb'.

   * If you are compiling from a Bazaar tree or making changes to the
     parser, you need `bison' for Windows, which can be downloaded from
     `http://gnuwin32.sourceforge.net/packages/bison.htm'.  Download
     the package labeled `Complete package, excluding sources'. After
     installing the package, modify your `PATH' environment variable to
     include the directory where `bison' is located.

   * Cygwin might be necessary if you want to run the test script or
     package the compiled binaries and support files into a Zip
     archive. (Cygwin is needed only to test or package the
     distribution, not to build it.) Cygwin is available from
     `http://cygwin.com'.

   * 3GB to 5GB of disk space.

There are three solutions available for building from the source code
on Windows:

   * Build from the standard MySQL source distribution. For this you
     will need `CMake' and Visual C++ Express Edition or Visual Studio.
     Using this method you can select the storage engines that are
     included in your build. To use this method, see *Note
     windows-source-build-cmake::.

   * Build from the MySQL Windows source distribution. The Windows
     source distribution includes ready-made Visual Studio solution
     files that enable support for all storage engines (except *Note
     `NDB': mysql-cluster.). To build using using method you only need
     Visual C++ Express Edition or Visual Studio. To use this method,
     see *Note windows-vc-plus-plus-build::.

   * Build directly from the Bazaar source repository. For this you
     will need `CMake', Visual C++ Express Edition or Visual Studio,
     and `bison'. For this method you need to create the distribution
     on a Unix system and then copy the generated files to your Windows
     build environment. To use this method, see *Note
     windows-sourcetree-build::.

If you find something not working as expected, or you have suggestions
about ways to improve the current build process on Windows, please send
a message to the `win32' mailing list. See *Note mailing-lists::.


File: manual.info,  Node: windows-source-build-cmake,  Next: windows-vc-plus-plus-build,  Prev: windows-source-build,  Up: windows-source-build

3.10.8.1 Building MySQL from the Standard Source Distribution
.............................................................

You can build MySQL on Windows by using a combination of `cmake' and
Microsoft Visual Studio .NET 2003 (7.1), Microsoft Visual Studio 2005
(8.0) or Microsoft Visual C++ 2005 Express Edition. You must have the
appropriate Microsoft Platform SDK installed.

*Note*:

To compile from the source code using `CMake' you must use the standard
source distribution (for example, `mysql-5.0.95.tar.gz'). You build
from the same distribution as used to build MySQL on Unix, Linux and
other platforms. Do _not_ use the Windows Source distributions as they
do not contain the necessary configuration script and other files.

Follow this procedure to build MySQL:

  1. If you are installing from a packaged source distribution, create
     a work directory (for example, `C:\workdir'), and unpack the source
     distribution there using `WinZip' or another Windows tool that can
     read `.zip' files. This directory is the work directory in the
     following instructions.

  2. If you are installing from a Bazaar tree, the root directory of
     that tree is the work directory in the following instructions.

  3. Using a command shell, navigate to the work directory and run the
     following command:

          C:\workdir>win\configure.js OPTIONS

     If you have associated the `.js' file extension with an
     application such as a text editor, then you may need to use the
     following command to force `configure.js' to be executed as a
     script:

          C:\workdir>cscript win\configure.js OPTIONS

     These options are available for `configure.js':

        * `WITH_INNOBASE_STORAGE_ENGINE': Enable the `InnoDB' storage
          engine.

        * `WITH_PARTITION_STORAGE_ENGINE': Enable user-defined
          partitioning.

        * `WITH_ARCHIVE_STORAGE_ENGINE': Enable the `ARCHIVE' storage
          engine.

        * `WITH_BLACKHOLE_STORAGE_ENGINE': Enable the `BLACKHOLE'
          storage engine.

        * `WITH_EXAMPLE_STORAGE_ENGINE': Enable the `EXAMPLE' storage
          engine.

        * `WITH_FEDERATED_STORAGE_ENGINE': Enable the `FEDERATED'
          storage engine.

        * `MYSQL_SERVER_SUFFIX=SUFFIX': Server suffix, default none.

        * `COMPILATION_COMMENT=COMMENT': Server comment, default
          "Source distribution".

        * `MYSQL_TCP_PORT=PORT': Server port, default 3306.

        * `DISABLE_GRANT_OPTIONS': Disables the the `--bootstrap',
          `--skip-grant-tables', and `--init-file' options for *Note
          `mysqld': mysqld. This option is available as of MySQL 5.0.36.

     For example (type the command on one line):

          C:\workdir>win\configure.js WITH_INNOBASE_STORAGE_ENGINE »
                       WITH_PARTITION_STORAGE_ENGINE MYSQL_SERVER_SUFFIX=-pro

  4. From the work directory, execute the `win\build-vs8.bat' or
     `win\build-vs71.bat' file, depending on the version of Visual
     Studio you have installed. The script invokes `CMake', which
     generates the `mysql.sln' solution file you will need to build
     MySQL using Visual Studio..

     You can also use `win\build-vs8_x64.bat' to build the 64-bit
     version of MySQL. However, you cannot build the 64-bit version
     with Visual Studio Express Edition.  You must use Visual Studio
     2005 (8.0) or higher.

  5. From the work directory, open the generated `mysql.sln' file with
     Visual Studio and select the proper configuration using the
     `Configuration' menu. The menu provides `Debug', `Release',
     `RelwithDebInfo', `MinRelInfo' options. Then select `Solution' >
     `Build' to build the solution.

     The build process will take some time. Please be patient.

     Remember the configuration that you use in this step. It is
     important later when you run the test script because that script
     needs to know which configuration you used.

  6. You should test you build before installation. See *Note
     windows-source-testbuild::.

  7. To install, use the instructions in *Note windows-source-install::.


File: manual.info,  Node: windows-vc-plus-plus-build,  Next: windows-source-install,  Prev: windows-source-build-cmake,  Up: windows-source-build

3.10.8.2 Building MySQL from a Windows Source Distribution
..........................................................

The Windows source distribution includes the necessary solution file
and the `vcproj' files required to build each component. Using this
method you are not able to select the storage engines that are included
in your build.

*Note*:

VC++ workspace files for MySQL 4.1 and above are compatible with
Microsoft Visual Studio 7.1 and tested by us before each release.

Follow this procedure to build MySQL:

  1. Create a work directory (for example, `C:\workdir').

  2. Unpack the source distribution in the aforementioned directory
     using `WinZip' or another Windows tool that can read `.zip' files.

  3. Start Visual Studio .Net 2003 (7.1).

  4. From the `File' menu, select `Open Solution...'.

  5. Open the `mysql.sln' solution you find in the work directory.

  6. From the `Build' menu, select `Configuration Manager...'.

  7. In the `Active Solution Configuration' pop-up menu, select the
     configuration to use. You likely want to use one of `nt' (normal
     server), `Max nt' (more engines and features), or `Debug'
     configuration.

  8. From the `Build' menu, select `Build Solution'.

  9. Debug versions of the programs and libraries are placed in the
     `client_debug' and `lib_debug' directories. Release versions of
     the programs and libraries are placed in the `client_release' and
     `lib_release' directories.

 10. You should test you build before installation. See *Note
     windows-source-testbuild::.

 11. To install, use the instructions in *Note windows-source-install::.


File: manual.info,  Node: windows-source-install,  Next: windows-source-testbuild,  Prev: windows-vc-plus-plus-build,  Up: windows-source-build

3.10.8.3 Installing MySQL from a Source Build on Windows
........................................................

When you are satisfied that the program you have built is working
correctly, stop the server. Now you can install the distribution. There
are two ways to do this, either by using the supplied installation
script or by copying the files individually by hand.

To use the script method you must have Cygwin installed as the script
is a Shell script. To execute the installation process, run the *Note
`make_win_bin_dist': make-win-bin-dist. script in the `scripts'
directory of the MySQL source distribution (see *Note
make-win-bin-dist::). This is a shell script, so you must have Cygwin
installed if you want to use it. It creates a Zip archive of the built
executables and support files that you can unpack to your desired
installation location.

It is also possible to install MySQL by copying directories and files
manually:

  1. Create the directories where you want to install MySQL. For
     example, to install into `C:\mysql', use these commands:

          shell> mkdir C:\mysql
          shell> mkdir C:\mysql\bin
          shell> mkdir C:\mysql\data
          shell> mkdir C:\mysql\share
          shell> mkdir C:\mysql\scripts

     If you want to compile other clients and link them to MySQL, you
     should also create several additional directories:

          shell> mkdir C:\mysql\include
          shell> mkdir C:\mysql\lib
          shell> mkdir C:\mysql\lib\debug
          shell> mkdir C:\mysql\lib\opt

     If you want to benchmark MySQL, create this directory:

          shell> mkdir C:\mysql\sql-bench

     Benchmarking requires Perl support. See *Note perl-support::.

  2. From the work directory, copy into the `C:\mysql' directory the
     following directories:

          shell> cd \workdir
          C:\workdir> copy client_release\*.exe C:\mysql\bin
          C:\workdir> copy client_debug\mysqld.exe C:\mysql\bin\mysqld-debug.exe
          C:\workdir> xcopy scripts\*.* C:\mysql\scripts /E
          C:\workdir> xcopy share\*.* C:\mysql\share /E

     If you want to compile other clients and link them to MySQL, you
     should also copy several libraries and header files:

          C:\workdir> copy lib_debug\mysqlclient.lib C:\mysql\lib\debug
          C:\workdir> copy lib_debug\libmysql.* C:\mysql\lib\debug
          C:\workdir> copy lib_debug\zlib.* C:\mysql\lib\debug
          C:\workdir> copy lib_release\mysqlclient.lib C:\mysql\lib\opt
          C:\workdir> copy lib_release\libmysql.* C:\mysql\lib\opt
          C:\workdir> copy lib_release\zlib.* C:\mysql\lib\opt
          C:\workdir> copy include\*.h C:\mysql\include
          C:\workdir> copy libmysql\libmysql.def C:\mysql\include

     If you want to benchmark MySQL, you should also do this:

          C:\workdir> xcopy sql-bench\*.* C:\mysql\bench /E

After installation, set up and start the server in the same way as for
binary Windows distributions. See *Note windows-installation::.


File: manual.info,  Node: windows-source-testbuild,  Next: windows-sourcetree-build,  Prev: windows-source-install,  Up: windows-source-build

3.10.8.4 Testing a Windows Source Build
.......................................

You should test the server that you have built from source before using
the distribution.

To test the server you need to run the built *Note `mysqld': mysqld. By
default, using the source build examples, the MySQL base directory and
data directory are `C:\mysql' and `C:\mysql\data'. If you want to test
your server using the source tree root directory and its data directory
as the base directory and data directory, you need to tell the server
their path names. You can either do this on the command line with the
`--basedir' and `--datadir' options, or by placing appropriate options
in an option file. (See *Note option-files::.) If you have an existing
data directory elsewhere that you want to use, you can specify its path
name instead.

When the server is running in standalone fashion or as a service based
on your configuration, try to connect to it from the *Note `mysql':
mysql. interactive command-line utility.

You can also run the standard test script, `mysql-test-run.pl'. This
script is written in Perl, so you'll need either Cygwin or ActiveState
Perl to run it. You may also need to install the modules required by the
script. To run the test script, change location into the `mysql-test'
directory under the work directory, set the `MTR_VS_CONFIG' environment
variable to the configuration you selected earlier (or use the
`--vs-config' option), and invoke `mysql-test-run.pl'. For example
(using Cygwin and the `bash' shell):

     shell> `cd mysql-test'
     shell> `export MTR_VS_CONFIG=debug'
     shell> `./mysql-test-run.pl --force --timer'
     shell> `./mysql-test-run.pl --force --timer --ps-protocol'


File: manual.info,  Node: windows-sourcetree-build,  Prev: windows-source-testbuild,  Up: windows-source-build

3.10.8.5 Creating a Windows Source Package from the Bazaar Repository
.....................................................................

To create a Windows source package from the current Bazaar source tree,
use the instructions here. This procedure must be performed on a system
running a Unix or Unix-like operating system because some of the
configuration and build steps require tools that work only on Unix. For
example, the following procedure is known to work well on Linux.

  1. Copy the Bazaar source tree for MySQL 5.0. For instructions on how
     to do this, see *Note installing-development-tree::.

  2. Configure and build the distribution so that you have a server
     binary to work with. One way to do this is to run the following
     command in the top-level directory of your source tree:

          shell> ./BUILD/compile-pentium-max

  3. After making sure that the build process completed successfully,
     run the following utility script from top-level directory of your
     source tree:

          shell> ./scripts/make_win_src_distribution

     This script creates a Windows source package to be used on your
     Windows system. You can supply different options to the script
     based on your needs. See *Note make-win-src-distribution::, for a
     list of permissible options.

     By default, *Note `make_win_src_distribution':
     make-win-src-distribution.  creates a Zip-format archive with the
     name `mysql-VERSION-win-src.zip', where VERSION represents the
     version of your MySQL source tree.

  4. Copy or upload the Windows source package that you have just
     created to your Windows machine. To compile it, use the
     instructions in *Note windows-vc-plus-plus-build::.


File: manual.info,  Node: macosx-installation,  Next: linux-installation-rpm,  Prev: windows-installation,  Up: installing

3.11 Installing MySQL on Mac OS X
=================================

You can install MySQL on Mac OS X 10.3.x (`Panther') or newer using a
Mac OS X binary package in PKG format instead of the binary tarball
distribution. Please note that older versions of Mac OS X (for example,
10.1.x or 10.2.x) are *not* supported by this package.

The package is located inside a disk image (`.dmg') file that you first
need to mount by double-clicking its icon in the Finder. It should then
mount the image and display its contents.

When installing from the package version, you should also install the
MySQL Preference Pane, which will enable you to control the startup and
execution of your MySQL server from System Preferences.

To obtain MySQL, see *Note getting-mysql::.

*Note*:

Before proceeding with the installation, be sure to shut down all
running MySQL server instances by using either the MySQL Manager
Application (on Mac OS X Server) or *Note `mysqladmin shutdown':
mysqladmin. on the command line.

To actually install the MySQL PKG file, double-click the package icon.
This launches the Mac OS X Package Installer, which guides you through
the installation of MySQL.

Due to a bug in the Mac OS X package installer, you may see this error
message in the destination disk selection dialog:

     You cannot install this software on this disk. (null)

If this error occurs, simply click the `Go Back' button once to return
to the previous screen. Then click `Continue' to advance to the
destination disk selection again, and you should be able to choose the
destination disk correctly. We have reported this bug to Apple and it is
investigating this problem.

The Mac OS X PKG of MySQL installs itself into
`/usr/local/mysql-VERSION' and also installs a symbolic link,
`/usr/local/mysql', that points to the new location. If a directory
named `/usr/local/mysql' exists, it is renamed to
`/usr/local/mysql.bak' first. Additionally, the installer creates the
grant tables in the `mysql' database by executing *Note
`mysql_install_db': mysql-install-db.

The installation layout is similar to that of a `tar' file binary
distribution; all MySQL binaries are located in the directory
`/usr/local/mysql/bin'. The MySQL socket file is created as
`/tmp/mysql.sock' by default. See *Note installation-layouts::.

MySQL installation requires a Mac OS X user account named `mysql'. A
user account with this name should exist by default on Mac OS X 10.2
and up.

If you are running Mac OS X Server, a version of MySQL should already
be installed. The following table shows the versions of MySQL that ship
with Mac OS X Server versions.

Mac OS X Server        MySQL Version
Version                
10.2-10.2.2            3.23.51
10.2.3-10.2.6          3.23.53
10.3                   4.0.14
10.3.2                 4.0.16
10.4.0                 4.1.10a

This manual section covers the installation of the official MySQL Mac
OS X PKG only. Make sure to read Apple's help information about
installing MySQL: Run the `Help View' application, select `Mac OS X
Server' help, do a search for `MySQL,' and read the item entitled
`Installing MySQL.'

For preinstalled versions of MySQL on Mac OS X Server, note especially
that you should start *Note `mysqld': mysqld. with `safe_mysqld'
instead of *Note `mysqld_safe': mysqld-safe. if MySQL is older than
version 4.0.

If you previously used Marc Liyanage's MySQL packages for Mac OS X from
`http://www.entropy.ch', you can simply follow the update instructions
for packages using the binary installation layout as given on his pages.

If you are upgrading from Marc's 3.23.x versions or from the Mac OS X
Server version of MySQL to the official MySQL PKG, you also need to
convert the existing MySQL privilege tables to the current format,
because some new security privileges have been added. See *Note
mysql-upgrade::.

If you want MySQL to start automatically during system startup, you
also need to install the MySQL Startup Item. It is part of the Mac OS X
installation disk images as a separate installation package. Simply
double-click the `MySQLStartupItem.pkg' icon and follow the
instructions to install it. The Startup Item need be installed only
once. There is no need to install it each time you upgrade the MySQL
package later.

The Startup Item for MySQL is installed into
`/Library/StartupItems/MySQLCOM'. (Before MySQL 4.1.2, the location was
`/Library/StartupItems/MySQL', but that collided with the MySQL Startup
Item installed by Mac OS X Server.) Startup Item installation adds a
variable `MYSQLCOM=-YES-' to the system configuration file
`/etc/hostconfig'. If you want to disable the automatic startup of
MySQL, simply change this variable to `MYSQLCOM=-NO-'.

On Mac OS X Server, the default MySQL installation uses the variable
`MYSQL' in the `/etc/hostconfig' file. The MySQL Startup Item installer
disables this variable by setting it to `MYSQL=-NO-'. This avoids boot
time conflicts with the `MYSQLCOM' variable used by the MySQL Startup
Item. However, it does not shut down a running MySQL server. You should
do that yourself.

After the installation, you can start up MySQL by running the following
commands in a terminal window. You must have administrator privileges
to perform this task.

If you have installed the Startup Item, use this command:

     shell> sudo /Library/StartupItems/MySQLCOM/MySQLCOM start
     (ENTER YOUR PASSWORD, IF NECESSARY)
     (PRESS CONTROL-D OR ENTER "EXIT" TO EXIT THE SHELL)

If you do not use the Startup Item, enter the following command
sequence:

     shell> cd /usr/local/mysql
     shell> sudo ./bin/mysqld_safe
     (ENTER YOUR PASSWORD, IF NECESSARY)
     (PRESS CONTROL-Z)
     shell> bg
     (PRESS CONTROL-D OR ENTER "EXIT" TO EXIT THE SHELL)

You should be able to connect to the MySQL server, for example, by
running `/usr/local/mysql/bin/mysql'.

*Note*:

The accounts that are listed in the MySQL grant tables initially have
no passwords. After starting the server, you should set up passwords
for them using the instructions in *Note postinstallation::.

You might want to add aliases to your shell's resource file to make it
easier to access commonly used programs such as *Note `mysql': mysql.
and *Note `mysqladmin': mysqladmin. from the command line. The syntax
for `bash' is:

     alias mysql=/usr/local/mysql/bin/mysql
     alias mysqladmin=/usr/local/mysql/bin/mysqladmin

For `tcsh', use:

     alias mysql /usr/local/mysql/bin/mysql
     alias mysqladmin /usr/local/mysql/bin/mysqladmin

Even better, add `/usr/local/mysql/bin' to your `PATH' environment
variable. You can do this by modifying the appropriate startup file for
your shell. For more information, see *Note invoking-programs::.

If you are upgrading an existing installation, note that installing a
new MySQL PKG does not remove the directory of an older installation.
Unfortunately, the Mac OS X Installer does not yet offer the
functionality required to properly upgrade previously installed
packages.

To use your existing databases with the new installation, you'll need
to copy the contents of the old data directory to the new data
directory. Make sure that neither the old server nor the new one is
running when you do this. After you have copied over the MySQL database
files from the previous installation and have successfully started the
new server, you should consider removing the old installation files to
save disk space. Additionally, you should also remove older versions of
the Package Receipt directories located in
`/Library/Receipts/mysql-VERSION.pkg'.


File: manual.info,  Node: linux-installation-rpm,  Next: solaris-installation,  Prev: macosx-installation,  Up: installing

3.12 Installing MySQL from RPM Packages on Linux
================================================

The recommended way to install MySQL on RPM-based Linux distributions
is by using the RPM packages. The RPMs that we provide to the community
should work on all versions of Linux that support RPM packages and use
`glibc' 2.3. We also provide RPMs with binaries that are statically
linked to a patched version of `glibc' 2.2, but only for the x86
(32-bit) architecture. To obtain RPM packages, see *Note
getting-mysql::.

For non-RPM Linux distributions, you can install MySQL using a
`.tar.gz' package. See *Note binary-installation::.

We do provide some platform-specific RPMs; the difference between a
platform-specific RPM and a generic RPM is that a platform-specific RPM
is built on the targeted platform and is linked dynamically whereas a
generic RPM is linked statically with LinuxThreads.

*Note*:

RPM distributions of MySQL are also provided by other vendors.  Be
aware that they may differ from those built by us in features,
capabilities, and conventions (including communication setup), and that
the instructions in this manual do not necessarily apply to installing
them. The vendor's instructions should be consulted instead.

If you have problems with an RPM file (for example, if you receive the
error `Sorry, the host 'XXXX' could not be looked up'), see *Note
binary-notes-linux::.

In most cases, you need to install only the `MySQL-server' and
`MySQL-client' packages to get a functional MySQL installation. The
other packages are not required for a standard installation.

For upgrades, if your installation was originally produced by
installing multiple RPM packages, it is best to upgrade all the
packages, not just some. For example, if you previously installed the
server and client RPMs, do not upgrade just the server RPM.

If you get a dependency failure when trying to install MySQL packages
(for example, `error: removing these packages would break dependencies:
libmysqlclient.so.10 is needed by ...'), you should also install the
`MySQL-shared-compat' package, which includes the shared libraries for
older releases for backward compatibility.

Some Linux distributions still ship with MySQL 3.23 and they usually
link applications dynamically to save disk space. If these shared
libraries are in a separate package (for example, `MySQL-shared'), it
is sufficient to simply leave this package installed and just upgrade
the MySQL server and client packages (which are statically linked and
do not depend on the shared libraries). For distributions that include
the shared libraries in the same package as the MySQL server (for
example, Red Hat Linux), you could either install our 3.23
`MySQL-shared' RPM, or use the `MySQL-shared-compat' package instead.
(Do not install both.)

The RPM packages shown in the following list are available. The names
shown here use a suffix of `.glibc23.i386.rpm', but particular packages
can have different suffixes, as described later. Packages that have
`community' in the names are Community Server builds, available from
MySQL 5.0.27 on.

   * `MySQL-server-VERSION.glibc23.i386.rpm',
     `MySQL-server-community-VERSION.glibc23.i386.rpm'

     The MySQL server. You need this unless you only want to connect to
     a MySQL server running on another machine.

   * `MySQL-client-VERSION.glibc23.i386.rpm',
     `MySQL-client-community-VERSION.glibc23.i386.rpm'

     The standard MySQL client programs. You probably always want to
     install this package.

   * `MySQL-bench-VERSION.glibc23.i386.rpm'

     Tests and benchmarks. Requires Perl and the `DBI' and `DBD::mysql'
     modules.

   * `MySQL-devel-VERSION.glibc23.i386.rpm',
     `MySQL-devel-community-VERSION.glibc23.i386.rpm'

     The libraries and include files that are needed if you want to
     compile other MySQL clients, such as the Perl modules.

   * `MySQL-debuginfo-VERSION.glibc23.i386.rpm',
     `MySQL-community-debuginfo-VERSION.glibc23.i386.rpm'

     This package contains debugging information.  `debuginfo' RPMs are
     never needed to use MySQL software; this is true both for the
     server and for client programs. However, they contain additional
     information that might be needed by a debugger to analyze a crash.

   * `MySQL-shared-VERSION.glibc23.i386.rpm',
     `MySQL-shared-community-VERSION.glibc23.i386.rpm'

     This package contains the shared libraries (`libmysqlclient.so*')
     that certain languages and applications need to dynamically load
     and use MySQL. It contains single-threaded and thread-safe
     libraries. If you install this package, do not install the
     `MySQL-shared-compat' package.

   * `MySQL-shared-compat-VERSION.glibc23.i386.rpm'

     This package includes the shared libraries for older releases, up
     to the current release. It contains single-threaded and
     thread-safe libraries. Install this package instead of
     `MySQL-shared' if you have applications installed that are
     dynamically linked against older versions of MySQL but you want to
     upgrade to the current version without breaking the library
     dependencies.

   * `MySQL-clustermanagement-communityVERSION.glibc23.i386.rpm',
     `MySQL-clusterstorage-communityVERSION.glibc23.i386.rpm',
     `MySQL-clustertools-communityVERSION.glibc23.i386.rpm',
     `MySQL-clusterextra-communityVERSION.glibc23.i386.rpm'

     Packages that contain additional files for MySQL Cluster
     installations. These are platform-specific RPMs, in contrast to
     the platform-independent `ndb-XXX' RPMs.

     *Note*:

     The `MySQL-clustertools' RPM requires a working installation of
     perl and the `DBI' and `HTML::Template' packages. See *Note
     perl-support::, and *Note mysql-cluster-programs-ndb-size-pl::, for
     more information.

   * `MySQL-ndb-management-VERSION.glibc23.i386.rpm',
     `MySQL-ndb-storage-VERSION.glibc23.i386.rpm',
     `MySQL-ndb-tools-VERSION.glibc23.i386.rpm',
     `MySQL-ndb-extra-VERSION.glibc23.i386.rpm'

     Packages that contain additional files for MySQL Cluster
     installations. These are platform-independent RPMs, in contrast to
     the platform-specific `clusterXXX-community' RPMs.

   * `MySQL-test-community-VERSION.glibc23.i386.rpm'

     This package includes the MySQL test suite.

   * `MySQL-VERSION.src.rpm'

     This contains the source code for all of the previous packages. It
     can also be used to rebuild the RPMs on other architectures (for
     example, Alpha or SPARC).

The suffix of RPM package names (following the VERSION value) has the
following syntax:

     [.PLATFORM].CPU.rpm

The PLATFORM and CPU values indicate the type of system for which the
package is built.  PLATFORM, if present, indicates the platform, and
CPU indicates the processor type or family.

If the PLATFORM value is missing (for example,
`MySQL-server-VERSION.i386.rpm'), the package is statically linked
against a version of `glibc' 2.2 that has been patched to handle larger
numbers of threads with larger stack sizes than the stock library.

If PLATFORM is present, the package is dynamically linked against
`glibc' 2.3 and the PLATFORM value indicates whether the package is
platform independent or intended for a specific platform, as shown in
the following table.

PLATFORM Value     Intended Use
`glibc23'          Platform independent, should run on any Linux
                   distribution that supports `glibc' 2.3
`rhel4', `rhel5'   Red Hat Enterprise Linux 4 or 5
`sles10'           SuSE Linux Enterprise Server 10

The CPU value indicates the processor type or family for which the
package is built.

CPU Value          Intended Processor Type or Family
`i386', `i586',    Pentium processor or better, 32 bit
`i686'             
`x86_64'           64-bit x86 processor
`ia64'             Itanium (IA-64) processor

To see all files in an RPM package (for example, a `MySQL-server' RPM),
run a command like this:

     shell> rpm -qpl MySQL-server-VERSION.glibc23.i386.rpm

To perform a standard minimal installation, install the server and
client RPMs:

     shell> rpm -i MySQL-server-VERSION.glibc23.i386.rpm
     shell> rpm -i MySQL-client-VERSION.glibc23.i386.rpm

To install only the client programs, install just the client RPM:

     shell> rpm -i MySQL-client-VERSION.glibc23.i386.rpm

RPM provides a feature to verify the integrity and authenticity of
packages before installing them. If you would like to learn more about
this feature, see *Note verifying-package-integrity::.

The server RPM places data under the `/var/lib/mysql' directory. The
RPM also creates a login account for a user named `mysql' (if one does
not exist) to use for running the MySQL server, and creates the
appropriate entries in `/etc/init.d/' to start the server automatically
at boot time. (This means that if you have performed a previous
installation and have made changes to its startup script, you may want
to make a copy of the script so that you do not lose it when you
install a newer RPM.) See *Note automatic-start::, for more information
on how MySQL can be started automatically on system startup.

If the RPM files that you install include `MySQL-server', the *Note
`mysqld': mysqld.  server should be up and running after installation.
You should be able to start using MySQL.

If something goes wrong, you can find more information in the binary
installation section. See *Note binary-installation::.

*Note*:

The accounts that are listed in the MySQL grant tables initially have
no passwords. After starting the server, you should set up passwords
for them using the instructions in *Note postinstallation::.

During RPM installation, a user named `mysql' and a group named `mysql'
are created on the system.  This is done using the `useradd',
`groupadd', and `usermod' commands. Those commands require appropriate
administrative privileges, which is ensured for locally managed users
and groups (as listed in the `/etc/passwd' and `/etc/group' files) by
the RPM installation process being run by `root'.

If you log in as the `mysql' user, you may find that MySQL displays
`Invalid (old?) table or database name' errors that mention `.mysqlgui',
`lost+found', `.mysqlgui', `.bash_history', `.fonts.cache-1',
`.lesshst', `.mysql_history', `.profile', `.viminfo', and similar files
created by MySQL or operating system utilities. You can safely ignore
these error messages or remove the files or directories that cause them
if you do not need them.

For nonlocal user management (LDAP, NIS, and so forth), the
administrative tools may require additional authentication (such as a
password), and will fail if the installing user does not provide this
authentication. Even if they fail, the RPM installation will not abort
but succeed, and this is intentional.  If they failed, some of the
intended transfer of ownership may be missing, and it is recommended
that the system administrator then manually ensures some appropriate
user andgroup exists and manually transfers ownership following the
actions in the RPM spec file.


File: manual.info,  Node: solaris-installation,  Next: i5os-installation,  Prev: linux-installation-rpm,  Up: installing

3.13 Installing MySQL on Solaris
================================

To obtain a binary MySQL distribution for Solaris in tarball or PKG
format, `http://dev.mysql.com/downloads/mysql/5.0.html'.

If you install MySQL using a binary tarball distribution on Solaris,
you may run into trouble even before you get the MySQL distribution
unpacked, as the Solaris `tar' cannot handle long file names. This
means that you may see errors when you try to unpack MySQL.

If this occurs, you must use GNU `tar' (`gtar') to unpack the
distribution.

You can install MySQL on Solaris using a binary package in PKG format
instead of the binary tarball distribution. Before installing using the
binary PKG format, you should create the `mysql' user and group, for
example:

     groupadd mysql
     useradd -g mysql mysql

Some basic PKG-handling commands follow:

   * To add a package:

          pkgadd -d PACKAGE_NAME.pkg

   * To remove a package:

          pkgrm PACKAGE_NAME

   * To get a full list of installed packages:

          pkginfo

   * To get detailed information for a package:

          pkginfo -l PACKAGE_NAME

   * To list the files belonging to a package:

          pkgchk -v PACKAGE_NAME

   * To get packaging information for an arbitrary file:

          pkgchk -l -p FILE_NAME

For additional information about installing MySQL on Solaris, see *Note
solaris::.


File: manual.info,  Node: i5os-installation,  Next: netware-installation,  Prev: solaris-installation,  Up: installing

3.14 Installing MySQL on i5/OS
==============================

The i5/OS POWER MySQL package was created in cooperation with IBM.
MySQL works within the Portable Application Solution Environment (PASE)
on the System i series of hardware and will also provide database
services for the Zend Core for i5/OS.

MySQL for i5/OS is provided both as a `tar' file and as a save file
(`.savf') package that can be downloaded and installed directly without
any additional installation steps required. To install MySQL using the
`tar' file, see *Note binary-installation::.

MySQL is only supported on i5/OS V5R4 or later releases. The i5/OS PASE
must be installed for MySQL to operate. You must be able to login as a
user in `*SECOFR' class.

You should the installation notes and tips for i5/OS before starting
installation. See i5/OS Installation Notes.

*Before Installation:*

*Note*:

The installation package will use an existing configuration if you have
previously installed MySQL (which is identified by looking for the file
`/etc/my.cnf'). The values for the data directory (`DATADIR') and owner
of the MySQL files (`USRPRF') specified during the installation will be
ignored, and the values determined from the `/etc/my.cnf' will be used
instead.

If you want to change these parameters during a new install, you should
temporarily rename `/etc/my.cnf', install MySQL using the new
parameters you want to use, and then merge your previous `/etc/my.cnf'
configuration settings with the new `/etc/my.cnf' file that is created
during installation.

   * You must have a user profile with PASE with suitable privileges.
     The user should be within the `*SECOFR' class, such as the
     `QSECOFR' user ID. You can use the `WRKUSRPRF' command to check
     your user profile.

   * For network connections to MySQL, you must have TCP/IP enabled.
     You should also check the following:

        * Ensure that a name has defined for the system. Run the
          Configure TCP/IP (`CFGTCP') command and select option 12
          (Change TCP/IP domain information) to display this setting.
          Make sure that a value is listed in the Host name field.

        * Make sure that the system has a loopback entry which
          represents the `localhost' or `127.0.0.1'.

        * Ensure that the IP address of the IBM i machine is mapped
          correctly to the host name.

To install MySQL on i5/OS, follow these steps:

  1. On the System i machine, create a save file that will be used to
     receive the downloaded installation save file. The file should be
     located within the General Purpose Library (`QGPL'):

          CRTSAVF FILE(QGPL/MYSQLINST) TESXT('MySQL Save file')

  2. Download the MySQL installation save file in 32-bit
     (`mysql-5.0.82-i5os-power-32bit.savf') or 64-bit
     (`mysql-5.0.82-i5os-power-64bit.savf') from MySQL Downloads
     (http://dev.mysql.com/downloads).

  3. You need to FTP the downloaded `.savf' file directly into the
     `QGPL/MYSQLINST' file on the System i server. You can do this
     through FTP using the following steps after logging in to the
     System i machine:

          ftp> bin
          ftp> cd qgpl
          ftp> put mysql-5.0.82-i5os-power.savf mysqlinst

  4. Log into the System i server using a user in the `*SECOFR' class,
     such as the `QSECOFR' user ID.

  5. You need to restore the installation library stored in the `.savf'
     save file:

          RSTLIB MYSQLINST DEV(*SAVF) SAVF(QGPL/MYSQLINST) MBROPT(*ALL) ALWOBJDIF(*ALL)

     *Note*:

     You can ignore the security changes-type message at the bottom of
     the installation panel.

  6. Once you have finished restoring the `MYSQLINST' library, check
     that all the necessary objects for installation are on the system
     by using the Display Library (`DSPLIB') command:

          DSPLIB LIB(MYSQLINST)

  7. You need to execute the installation command,
     `MYSQLINST/INSMYSQL'. You can specify three parameter settings
     during installation:

        * `DIR('/QOPENSYS/USR/LOCAL/MYSQL')' sets the installation
          location for the MySQL files. The directory will be created
          if it does not already exist.

        * `DATADIR('/QOPENSYS/USR/LOCAL/MYSQL/DATA')' sets the location
          of the directory that will be used to store the database
          files and binary logs. The default setting is
          `/QOpenSys/usr/local/mysql/data'. Note that if the installer
          detects an existing installation (due to the existence of
          `/etc/my.cnf'), then the existing setting will be used
          instead of the default.

        * `USRPRF(MYSQL)' sets the user profile that will own the files
          that are installed. The profile will be created if it does not
          already exist.

          *Note*:

          You should choose an appropriate user for using the MySQL
          server installation. The user will be used whenever you need
          to do any administration on the MySQL server.

     Once you have set the appropriate parameters, you can begin the
     installation.

     The installation copies all the necessary files into a directory
     matching the `DIR' configuration value; sets the ownership on
     those files, sets up the MySQL environment and creates the MySQL
     configuration file (in `/etc/my.cnf') completing all the steps in
     a typical binary installation process automatically. If this is a
     new installation of MySQL, or if the installer detects that this
     is a new version (because the `/etc/my.cnf' file does not exist),
     then the initial core MySQL databases will also be created during
     installation.

     Once the installation has been completed, you will get a notice
     advising you to set the password for the root user. For more
     information, *Note postinstallation::.

  8. Once the installation has completed, you can delete the
     installation file:

          DLTLIB LIB(MYSQLINST)

*Upgrading an existing MySQL instance*

You need to execute the upgrade command, `MYSQLINST/UPGMYSQL'.

*Note*:

You cannot use `MYSQLINST/UPGMYSQL' to upgrade between major versions
of MySQL (for example from 5.0 to 5.1).  For information and advice on
migrating between major versions you can use the advice provided in
*Note upgrading-from-previous-series::.

You must specify 6 parameters to perform an upgrade:

   * `DIR('/QOpenSys/usr/local/')': Sets the installation location for
     the MySQL files. The directory will be created if it does not
     already exist. This is the directory that the MySQL server will be
     installed into, inside a directory with a name matching the
     version and release. For example, if installing MySQL 5.0.82 with
     the `DIR' set to `/QOpenSys/usr/local/' would result in
     `/QOpenSys/usr/local/mysql-5.0.82-i5os-power64' and a symbolic
     link to this directory will be created in
     `/QOpenSys/usr/local/mysql'.

   * `DATADIR('/QOpenSys/mysql/data')': Sets the location of the
     directory that will be upgraded.

   * `USRPRF('MYSQL')': Sets the user profile that will own the files
     that are installed. The profile will be created if it does not
     already exist; if it is created as part of the upgrade process, it
     will be disabled initially. You may wish to enable this user
     profile so that it can be used to start the MySQL server later. It
     is best practice to use the one previously created during the
     first installation.

   * `MYSQLUSR('root user')': Any user account in the current MySQL
     server with `SUPER' privileges.

   * `PASSWORD('root user password')': The password for the above
     account. This is necessary as the upgrade starts the MySQL server
     to upgrade the tables and the password is need to be able to
     shutdown the MySQL server.

   * `CURINST('path to previous install')': The full path to the
     installation that is being upgraded. For example an installation in
     `/QOpenSys/usr/local/' will be
     `/QOpenSys/usr/local/mysql-5.1.30-i5os-power64'.  Failure to
     specify this option may result in corruption of your existing data
     files.

For example:

     MYSQLINST/UPGMYSQL DIR('/QOPENSYS/USR/LOCAL/') DATADIR('/QOPENSYS/MYSQL/DATA') »
          USERPRF(MYSQL) MYSQLUSR('ROOT') PASSWORD('ROOT') CURINST('/QOPENSYS/USR/LOCAL/MYSQL-5.1.30-I5OS-POWER64')

You should receive a Program Message indicating `UPGRADE SUCCESSFUL!'
upon completion or an error message if there is a problem.You can view
the upgrade programs progression and the error in the text file
`upgrade.log' in the installation directory.

*To start MySQL*:

  1. Log into the System i server using the user profile create or
     specified during installation. By default, this is `MYSQL'.

     *Note*:

     You should start *Note `mysqld_safe': mysqld-safe. using a user
     that in the PASE environment has the id=0 (the equivalent of the
     standard Unix `root' user). If you do not use a user with this ID
     then the system will be unable to change the user when executing
     *Note `mysqld': mysqld.  as set using `--user' option. If this
     happens, *Note `mysqld': mysqld. may be unable to read the files
     located within the MySQL data directory and the execution will
     fail.

  2. Enter the PASE environment using `call qp2term'.

  3. Start the MySQL server by changing to the installation directory
     and running *Note `mysqld_safe': mysqld-safe, specifying the user
     name used to install the server. The installer conveniently
     installs a symbolic link to the installation directory
     (`mysql-5.0.42-i5os-power-32bit') as `/opt/mysql/mysql':

          > cd /opt/mysql/mysql
          > bin/mysqld_safe --user=mysql &

     You should see a message similar to the following:

          Starting mysqld daemon with databases »
               from /opt/mysql/mysql-enterprise-5.0.42-i5os-power-32bit/data

If you are having problems starting MySQL server, see *Note
starting-server::.

*To stop MySQL*:

  1. Log into the System i server using the user profile create or
     specified during installation. By default, this is `MYSQL'.

  2. Enter the PASE environment using `call qp2term'.

  3. Stop the MySQL server by changing into the installation directory
     and running *Note `mysqladmin': mysqladmin, specifying the user
     name used to install the server:

          > cd /opt/mysql/mysql
          > bin/mysqladmin -u root shutdown

     If the session that you started and stopped MySQL are the same,
     you may get the log output from `mysqld':

             STOPPING server from pid file »
               /opt/mysql/mysql-enterprise-5.0.42-i5os-power-32bit/data/I5DBX.RCHLAND.IBM.COM.pid
             070718 10:34:20  mysqld ended

     If the sessions used to start and stop MySQL are different, you
     will not receive any confirmation of the shutdown.

_Note and tips_

   * A problem has been identified with the installation process on
     DBCS systems. If you are having problems install MySQL on a DBCS
     system, you need to change your job's coded character set
     identifier (`CSSID') to 37 (`EBCDIC') before executing the install
     command, `INSMYSQL'. To do this, determine your existing `CSSID'
     (using `DSPJOB' and selecting option 2), execute `CHGJOB
     CSSID(37)', run `INSMYSQL' to install MySQL and then execute
     `CHGJOB' again with your original `CSSID.'

   * If you want to use the Perl scripts that are included with MySQL,
     you need to download the iSeries Tools for Developers (5799-PTL).
     See `http://www-03.ibm.com/servers/enable/site/porting/tools/'.


File: manual.info,  Node: netware-installation,  Next: binary-installation,  Prev: i5os-installation,  Up: installing

3.15 Installing MySQL on NetWare
================================

Porting MySQL to NetWare was an effort spearheaded by Novell.  Novell
customers should be pleased to note that NetWare 6.5 ships with bundled
MySQL binaries, complete with an automatic commercial use license for
all servers running that version of NetWare.

MySQL for NetWare is compiled using a combination of Metrowerks
CodeWarrior for NetWare and special cross-compilation versions of the
GNU autotools.

The latest binary packages for NetWare can be obtained at
`http://dev.mysql.com/downloads/'. See *Note getting-mysql::.

To host MySQL, the NetWare server must meet these requirements:

   * The latest Support Pack of NetWare 6.5
     (http://support.novell.com/filefinder/18197/index.html) must be
     installed.

   * The system must meet Novell's minimum requirements to run the
     respective version of NetWare.

   * MySQL data and the program binaries must be installed on an NSS
     volume; traditional volumes are not supported.

To install MySQL for NetWare, use the following procedure:

  1. If you are upgrading from a prior installation, stop the MySQL
     server. This is done from the server console, using the following
     command:

          SERVER:  mysqladmin -u root shutdown

     *Note*:

     If the MySQL `root' user account has a password, you need to
     invoke *Note `mysqladmin': mysqladmin.  with the `-p' option and
     supply the password when prompted.

  2. Log on to the target server from a client machine with access to
     the location where you are installing MySQL.

  3. Extract the binary package Zip file onto the server. Be sure to
     allow the paths in the Zip file to be used. It is safe to simply
     extract the file to `SYS:\'.

     If you are upgrading from a prior installation, you may need to
     copy the data directory (for example, `SYS:MYSQL\DATA'), as well as
     `my.cnf', if you have customized it. You can then delete the old
     copy of MySQL.

  4. You might want to rename the directory to something more
     consistent and easy to use. The examples in this manual use
     `SYS:MYSQL' to refer to the installation directory.

     Note that MySQL installation on NetWare does not detect if a
     version of MySQL is already installed outside the NetWare release.
     Therefore, if you have installed the latest MySQL version from the
     Web (for example, MySQL 4.1 or later) in `SYS:\MYSQL', you must
     rename the folder before upgrading the NetWare server; otherwise,
     files in `SYS:\MySQL' are overwritten by the MySQL version present
     in NetWare Support Pack.

  5. At the server console, add a search path for the directory
     containing the MySQL NLMs. For example:

          SERVER:  SEARCH ADD SYS:MYSQL\BIN

  6. Initialize the data directory and the grant tables, if necessary,
     by executing *Note `mysql_install_db': mysql-install-db. at the
     server console.

  7. Start the MySQL server using *Note `mysqld_safe': mysqld-safe. at
     the server console.

  8. To finish the installation, you should also add the following
     commands to `autoexec.ncf'. For example, if your MySQL
     installation is in `SYS:MYSQL' and you want MySQL to start
     automatically, you could add these lines:

          #Starts the MySQL 5.0.x database server
          SEARCH ADD SYS:MYSQL\BIN
          MYSQLD_SAFE

     If you are running MySQL on NetWare 6.0, we strongly suggest that
     you use the `--skip-external-locking' option on the command line:

          #Starts the MySQL 5.0.x database server
          SEARCH ADD SYS:MYSQL\BIN
          MYSQLD_SAFE --skip-external-locking

     It is also necessary to use *Note `CHECK TABLE': check-table. and
     *Note `REPAIR TABLE': repair-table. instead of *Note `myisamchk':
     myisamchk, because *Note `myisamchk': myisamchk. makes use of
     external locking. External locking is known to have problems on
     NetWare 6.0; the problem has been eliminated in NetWare 6.5. Note
     that the use of MySQL on Netware 6.0 is not officially supported.

     *Note `mysqld_safe': mysqld-safe. on NetWare provides a screen
     presence. When you unload (shut down) the *Note `mysqld_safe':
     mysqld-safe. NLM, the screen does not go away by default. Instead,
     it prompts for user input:

          *<NLM has terminated; Press any key to close the screen>*

     If you want NetWare to close the screen automatically instead, use
     the `--autoclose' option to *Note `mysqld_safe': mysqld-safe. For
     example:

          #Starts the MySQL 5.0.x database server
          SEARCH ADD SYS:MYSQL\BIN
          MYSQLD_SAFE --autoclose

     The behavior of *Note `mysqld_safe': mysqld-safe. on NetWare is
     described further in *Note mysqld-safe::.

  9. When installing MySQL, either for the first time or upgrading from
     a previous version, download and install the latest and
     appropriate Perl module and PHP extensions for NetWare:

        * Perl:
          `http://forge.novell.com/modules/xfcontent/downloads.php/perl/Modules/'

        * PHP:
          `http://forge.novell.com/modules/xfcontent/downloads.php/php/Modules/'

If there was an existing installation of MySQL on the NetWare server,
be sure to check for existing MySQL startup commands in `autoexec.ncf',
and edit or delete them as necessary.

*Note*:

The accounts that are listed in the MySQL grant tables initially have
no passwords. After starting the server, you should set up passwords
for them using the instructions in *Note postinstallation::.


File: manual.info,  Node: binary-installation,  Next: source-installation,  Prev: netware-installation,  Up: installing

3.16 Installing MySQL from Generic Binaries on Other Unix-Like Systems
======================================================================

Oracle provides a set of binary distributions of MySQL. These include
binary distributions in the form of compressed `tar' files (files with a
`.tar.gz' extension) for a number of platforms, as well as binaries in
platform-specific package formats for selected platforms.

This section covers the installation of MySQL from a compressed `tar'
file binary distribution. For other platform-specific package formats,
see the other platform-specific sections. For example, for Windows
distributions, see *Note windows-installation::.

To obtain MySQL, see *Note getting-mysql::.

MySQL compressed `tar' file binary distributions have names of the form
`mysql-VERSION-OS.tar.gz', where `VERSION' is a number (for example,
`5.0.95'), and OS indicates the type of operating system for which the
distribution is intended (for example, `pc-linux-i686' or `winx64').

To install MySQL from a compressed `tar' file binary distribution, your
system must have GNU `gunzip' to uncompress the distribution and a
reasonable `tar' to unpack it. If your `tar' program supports the `z'
option, it can both uncompress and unpack the file.

GNU `tar' is known to work. The standard `tar' provided with some
operating systems is not able to unpack the long file names in the
MySQL distribution. You should download and install GNU `tar', or if
available, use a preinstalled version of GNU tar. Usually this is
available as `gnutar', `gtar', or as `tar' within a GNU or Free
Software directory, such as `/usr/sfw/bin' or `/usr/local/bin'. GNU
`tar' is available from `http://www.gnu.org/software/tar/'.

*Warning*:

If you have previously installed MySQL using your operating system
native package management system, such as `yum' or `apt-get', you may
experience problems installing using a native binary. Make sure your
previous MySQL previous installation has been removed entirely (using
your package management system), and that any additional files, such as
old versions of your data files, have also been removed. You should
also check the existence of configuration files such as `/etc/my.cnf'
or the `/etc/mysql' directory have been deleted.

If you run into problems and need to file a bug report, please use the
instructions in *Note bug-reports::.

To install and use a MySQL binary distribution, the basic command
sequence looks like this:

     shell> groupadd mysql
     shell> useradd -r -g mysql mysql
     shell> cd /usr/local
     shell> tar zxvf /PATH/TO/MYSQL-VERSION-OS.tar.gz
     shell> ln -s FULL-PATH-TO-MYSQL-VERSION-OS mysql
     shell> cd mysql
     shell> chown -R mysql .
     shell> chgrp -R mysql .
     shell> scripts/mysql_install_db --user=mysql
     shell> chown -R root .
     shell> chown -R mysql data
     # Next command is optional
     shell> cp support-files/my-medium.cnf /etc/my.cnf
     shell> bin/mysqld_safe --user=mysql &
     # Next command is optional
     shell> cp support-files/mysql.server /etc/init.d/mysql.server

A more detailed version of the preceding description for installing a
binary distribution follows.

*Note*:

This procedure assumes that you have `root' (administrator) access to
your system. Alternatively, you can prefix each command using the
`sudo' (Linux) or `pfexec' (OpenSolaris) command.

The procedure does not set up any passwords for MySQL accounts.  After
following the procedure, proceed to *Note postinstallation::.

* Create a `mysql' User and Group *

If your system does not already have a user and group for *Note
`mysqld': mysqld. to run as, you may need to create one. The following
commands add the `mysql' group and the `mysql' user. The syntax for
`useradd' and `groupadd' may differ slightly on different versions of
Unix, or they may have different names such as `adduser' and `addgroup'.

     shell> groupadd mysql
     shell> useradd -r -g mysql mysql

*Note*:

Because the user is required only for ownership purposes, not login
purposes, the `useradd' command uses the `-r' option to create a user
that does not have login permissions to your server. Omit this option
to permit logins for the user (or if your `useradd' does not support
the option).

You might want to call the user and group something else instead of
`mysql'. If so, substitute the appropriate name in the preceding
commands and in the following steps.

* Obtain and Unpack the Distribution *

Pick the directory under which you want to unpack the distribution and
change location into it. The example here unpacks the distribution
under `/usr/local'. The instructions, therefore, assume that you have
permission to create files and directories in `/usr/local'. If that
directory is protected, you must perform the installation as `root'.

     shell> cd /usr/local

Obtain a distribution file using the instructions in *Note
getting-mysql::. For a given release, binary distributions for all
platforms are built from the same MySQL source distribution.

Unpack the distribution, which creates the installation directory.
Then create a symbolic link to that directory.  `tar' can uncompress
and unpack the distribution if it has `z' option support:

     shell> tar zxvf /PATH/TO/MYSQL-VERSION-OS.tar.gz
     shell> ln -s FULL-PATH-TO-MYSQL-VERSION-OS mysql

The `tar' command creates a directory named `mysql-VERSION-OS'.  The
`ln' command makes a symbolic link to that directory. This enables you
to refer more easily to the installation directory as
`/usr/local/mysql'.

If your `tar' does not have `z' option support, use `gunzip' to unpack
the distribution and `tar' to unpack it. Replace the preceding `tar'
command with the following alternative command to uncompress and
extract the distribution:

     shell> gunzip < /PATH/TO/MYSQL-VERSION-OS.tar.gz | tar xvf -

* Perform Postinstallation Setup *

The remainder of the installation process involves setting up the
configuration file, creating the core databases, and starting the MySQL
server. For instructions, see *Note postinstallation::.

*Note*:

The accounts that are listed in the MySQL grant tables initially have
no passwords. After starting the server, you should set up passwords
for them using the instructions in *Note postinstallation::.


File: manual.info,  Node: source-installation,  Next: postinstallation,  Prev: binary-installation,  Up: installing

3.17 Installing MySQL from Source
=================================

* Menu:

* installing-source-distribution::  Installing MySQL from a Standard Source Distribution
* installing-development-tree::  Installing MySQL from a Development Source Tree
* source-configuration-options::  MySQL Source-Configuration Options
* compilation-problems::         Dealing with Problems Compiling MySQL
* compile-and-link-options::     Compiling and Linking an Optimized `mysqld' Server

Building MySQL from the source code enables you to customize build
parameters, compiler optimizations, and installation location. For a
list of systems on which MySQL is known to run, see *Note
supported-os::.

Before you proceed with an installation from source, check whether we
produce a precompiled binary distribution for your platform and whether
it works for you. We put a great deal of effort into ensuring that our
binaries are built with the best possible options for optimal
performance. Instructions for installing binary distributions are
available in *Note binary-installation::.

To obtain a source distribution for MySQL, see *Note getting-mysql::.
MySQL source distributions are available as compressed `tar' files, Zip
archives, or RPM packages. Distribution files have names of the form
`mysql-VERSION.tar.gz', `mysql-VERSION.zip', or `mysql-VERSION.rpm',
where VERSION is a number like `5.0.95'.

To perform a MySQL installation using the source code:

   * To build MySQL from source on Unix-like systems, including Linux,
     commercial Unix, BSD, Mac OS X and others using a `.tar.gz' or
     RPM-based source code distribution, see *Note
     installing-source-distribution::.

   * To build MySQL from source on Windows (Windows XP or newer
     required), see *Note windows-source-build::.

   * For information on building from one of our development trees, see
     *Note installing-development-tree::.

   * For information on using the `configure' command to specify the
     source build parameters, including links to platform specific
     parameters that you might need, see *Note
     source-configuration-options::.

To install MySQL from source, your system must have the following tools:

   * GNU `gunzip' to uncompress the distribution and a reasonable `tar'
     to unpack it (if you use a `.tar.gz' distribution), or `WinZip' or
     another tool that can read `.zip' files (if you use a `.zip'
     distribution).

     GNU `tar' is known to work. The standard `tar' provided with some
     operating systems is not able to unpack the long file names in the
     MySQL distribution. You should download and install GNU `tar', or
     if available, use a preinstalled version of GNU tar. Usually this
     is available as `gnutar', `gtar', or as `tar' within a GNU or Free
     Software directory, such as `/usr/sfw/bin' or `/usr/local/bin'.
     GNU `tar' is available from `http://www.gnu.org/software/tar/'.

   * A working ANSI C++ compiler. GCC 3.4.6 or later, Sun Studio 10 or
     later, Visual Studio 2005 or later, and many current
     vendor-supplied compilers are known to work.

   * A good `make' program. Although some platforms come with their own
     `make' implementations, it is highly recommended that you use GNU
     `make' 3.75 or newer. It may already be available on your system as
     `gmake'. GNU `make' is available from
     `http://www.gnu.org/software/make/'.

   * `libtool' 1.5, available from
     `http://www.gnu.org/software/libtool/'. 1.5.24 or later is
     recommended.

If you are using a version of `gcc' recent enough to understand the
`-fno-exceptions' option, it is _very important_ that you use this
option.  Otherwise, you may compile a binary that crashes randomly.
Also use `-felide-constructors' and `-fno-rtti' along with
`-fno-exceptions'. When in doubt, do the following:

     CFLAGS="-O3" CXX=gcc CXXFLAGS="-O3 -felide-constructors \
            -fno-exceptions -fno-rtti" ./configure \
            --prefix=/usr/local/mysql --enable-assembler \
            --with-mysqld-ldflags=-all-static

On most systems, this gives you a fast and stable binary.

If you run into problems and need to file a bug report, please use the
instructions in *Note bug-reports::.


File: manual.info,  Node: installing-source-distribution,  Next: installing-development-tree,  Prev: source-installation,  Up: source-installation

3.17.1 Installing MySQL from a Standard Source Distribution
-----------------------------------------------------------

To install MySQL from source, first configure, build, and install from
a source package. Then follow the same postinstallation setup sequence
as for a binary installation.

If you start from a source RPM, use the following command to make a
binary RPM that you can install. If you do not have `rpmbuild', use
`rpm' instead.

     shell> rpmbuild --rebuild --clean MySQL-VERSION.src.rpm

The result is one or more binary RPM packages that you install as
indicated in *Note linux-installation-rpm::.

The sequence for installation from a compressed `tar' file source
distribution is similar to the process for installing from a generic
binary distribution that is detailed in *Note binary-installation::.
For a MySQL `.tar.gz' source distribution, the basic installation
command sequence looks like this:

     # Preconfiguration setup
     shell> groupadd mysql
     shell> useradd -g mysql mysql
     # Beginning of source-build specific instructions
     shell> tar zxvf mysql-VERSION.tar.gz
     shell> cd mysql-VERSION
     shell> ./configure --prefix=/usr/local/mysql
     shell> make
     shell> make install
     # End of source-build specific instructions
     # Postinstallation setup
     shell> cd /usr/local/mysql
     shell> chown -R mysql .
     shell> chgrp -R mysql .
     shell> bin/mysql_install_db --user=mysql
     shell> chown -R root .
     shell> chown -R mysql var
     # Next command is optional
     shell> cp support-files/my-medium.cnf /etc/my.cnf
     shell> bin/mysqld_safe --user=mysql &
     # Next command is optional
     shell> cp support-files/mysql.server /etc/init.d/mysql.server

*Note*:

This procedure does not set up any passwords for MySQL accounts.  After
following the procedure, proceed to *Note postinstallation::, for
postinstallation setup and testing.

A more detailed version of the preceding description for installing
MySQL from a source distribution follows:

  1. Add a login user and group for *Note `mysqld': mysqld. to run as:

          shell> groupadd mysql
          shell> useradd -g mysql mysql

     These commands add the `mysql' group and the `mysql' user. The
     syntax for `useradd' and `groupadd' may differ slightly on
     different versions of Unix, or they may have different names such
     as `adduser' and `addgroup'.

     You might want to call the user and group something else instead
     of `mysql'. If so, substitute the appropriate name in the
     following steps.

  2. Perform the following steps as the `mysql' user, except as noted.

  3. Pick the directory under which you want to unpack the distribution
     and change location into it.

  4. Obtain a distribution file using the instructions in *Note
     getting-mysql::.

  5. Unpack the distribution into the current directory.  `tar' can
     uncompress and unpack the distribution if it has `z' option
     support:

          shell> tar zxvf /PATH/TO/MYSQL-VERSION.tar.gz

     This command creates a directory named `mysql-VERSION'.

     If your `tar' does not have `z' option support, use `gunzip' to
     unpack the distribution and `tar' to unpack it:

          shell> gunzip < /PATH/TO/MYSQL-VERSION.tar.gz | tar xvf -

  6. Change location into the top-level directory of the unpacked
     distribution:

          shell> cd mysql-VERSION

     Note that currently you must configure and build MySQL from this
     top-level directory. You cannot build it in a different directory.

  7. Configure the release and compile everything:

          shell> ./configure --prefix=/usr/local/mysql
          shell> make

     When you run `configure', you might want to specify other options.
     For example, if you need to debug *Note `mysqld': mysqld. or a
     MySQL client, run `configure' with the `--with-debug' option, and
     then recompile and link your clients with the new client library.
     See MySQL Internals: Porting
     (http://forge.mysql.com/wiki/MySQL_Internals_Porting).

     Run `./configure --help' for a list of options. *Note
     source-configuration-options::, discusses some of the more useful
     options.

     If `configure' fails and you are going to send mail to a MySQL
     mailing list to ask for assistance, please include any lines from
     `config.log' that you think can help solve the problem. Also
     include the last couple of lines of output from `configure'. To
     file a bug report, please use the instructions in *Note
     bug-reports::.

     If the compile fails, see *Note compilation-problems::, for help.

  8. Install the distribution:

          shell> make install

     You might need to run this command as `root'.

     If you want to set up an option file, use one of those present in
     the `support-files' directory as a template. For example:

          shell> cp support-files/my-medium.cnf /etc/my.cnf

     You might need to run this command as `root'.

     If you want to configure support for `InnoDB' tables, you should
     edit the `/etc/my.cnf' file, removing the `#' character before the
     option lines that start with `innodb_...', and modify the option
     values to be what you want. See *Note option-files::, and *Note
     innodb-configuration::.

  9. Change location into the installation directory:

          shell> cd /usr/local/mysql

 10. If you ran the `make install' command as `root', the installed
     files will be owned by `root'. Ensure that the installation is
     accessible to `mysql' by executing the following commands as
     `root' in the installation directory:

          shell> chown -R mysql .
          shell> chgrp -R mysql .

     The first command changes the owner attribute of the files to the
     `mysql' user. The second changes the group attribute to the
     `mysql' group.

 11. If you have not installed MySQL before, you must create the MySQL
     data directory and initialize the grant tables:

          shell> bin/mysql_install_db --user=mysql

     If you run the command as `root', include the `--user' option as
     shown. If you run the command while logged in as `mysql', you can
     omit the `--user' option.

     The command should create the data directory and its contents with
     `mysql' as the owner.

     After using *Note `mysql_install_db': mysql-install-db. to create
     the grant tables for MySQL, you must restart the server manually.
     The *Note `mysqld_safe': mysqld-safe. command to do this is shown
     in a later step.

 12. Most of the MySQL installation can be owned by `root' if you like.
     The exception is that the data directory must be owned by `mysql'.
     To accomplish this, run the following commands as `root' in the
     installation directory:

          shell> chown -R root .
          shell> chown -R mysql var

 13. If the plugin directory is writable by the server, it may be
     possible for a user to write executable code to a file in the
     directory using *Note `SELECT ... INTO DUMPFILE': select. This can
     be prevented by making `plugin_dir' read only to the server or by
     setting `--secure-file-priv' to a directory where *Note `SELECT':
     select. writes can be made safely.

 14. If you want MySQL to start automatically when you boot your
     machine, you can copy `support-files/mysql.server' to the location
     where your system has its startup files. More information can be
     found in the `support-files/mysql.server' script itself; see also
     *Note automatic-start::.

 15. You can set up new accounts using the `bin/mysql_setpermission'
     script if you install the `DBI' and `DBD::mysql' Perl modules. See
     *Note mysql-setpermission::. For Perl module installation
     instructions, see *Note perl-support::.

After everything has been installed, test the distribution. To start
the MySQL server, use the following command:

     shell> /usr/local/mysql/bin/mysqld_safe --user=mysql &

If you run the command as `root', you should use the `--user' option as
shown. The option value is the name of the login account that you
created in the first step to use for running the server. If you run the
*Note `mysqld_safe': mysqld-safe. command while logged in as that user,
you can omit the `--user' option.

If the command fails immediately and prints `mysqld ended', look for
information in the error log (which by default is the `HOST_NAME.err'
file in the data directory).

More information about *Note `mysqld_safe': mysqld-safe. is given in
*Note mysqld-safe::.

To make it more convenient to invoke programs installed in
`/usr/local/mysql/bin', you can add that directory to your `PATH'
environment variable setting. That enables you to run a program by
typing only its name, not its entire path name. See *Note
setting-environment-variables::.

*Note*:

The accounts that are listed in the MySQL grant tables initially have
no passwords. After starting the server, you should set up passwords
for them using the instructions in *Note postinstallation::.


File: manual.info,  Node: installing-development-tree,  Next: source-configuration-options,  Prev: installing-source-distribution,  Up: source-installation

3.17.2 Installing MySQL from a Development Source Tree
------------------------------------------------------

This section discusses how to install MySQL from the latest development
source code. Development trees have not necessarily received the same
level of testing as standard release distributions, so this
installation method is usually required only if you need the most
recent code changes. Do not use a development tree for production
systems. If your goal is simply to get MySQL up and running on your
system, you should use a standard release distribution (either a binary
or source distribution). See *Note getting-mysql::.

To obtain the source tree, you must have Bazaar installed. The Bazaar
VCS Web site (http://bazaar-vcs.org) has instructions for downloading
and installing Bazaar on different platforms. Bazaar is supported on
any platform that supports Python, and is therefore compatible with any
Linux, Unix, Windows, or Mac OS X host.

MySQL development projects are hosted on Launchpad
(http://launchpad.net/). MySQL projects, including MySQL Server, MySQL
Workbench, and others are available from the Oracle/MySQL Engineering
(http://launchpad.net/~mysql) page. For the repositories related only to
MySQL Server, see the MySQL Server (http://launchpad.net/mysql-server)
page.

For information about using Bazaar with MySQL, see
`http://forge.mysql.com/wiki/MySQL_Bazaar_Howto'.

To build under Unix/Linux, you must have the following tools installed:

   * A good `make' program. Although some platforms come with their own
     `make' implementations, it is highly recommended that you use GNU
     `make' 3.75 or newer. It may already be available on your system
     as `gmake'. GNU `make' is available from
     `http://www.gnu.org/software/make/'.

   * `autoconf' 2.58 (or newer), available from
     `http://www.gnu.org/software/autoconf/'.

   * `automake' 1.8.1, available from
     `http://www.gnu.org/software/automake/'.

   * `libtool' 1.5, available from
     `http://www.gnu.org/software/libtool/'. 1.5.24 or later is
     recommended.

   * `m4', available from `http://www.gnu.org/software/m4/'.

   * `bison', available from `http://www.gnu.org/software/bison/'. You
     should use the latest version of `bison' where possible. Versions
     1.75 and 2.1 are known to work. There have been reported problems
     with `bison' 1.875. If you experience problems, upgrade to a
     later, rather than earlier, version.

To build under Windows you must have Microsoft Visual C++ 2005 Express
Edition, Visual Studio .Net 2003 (7.1), or Visual Studio 2005 (8.0)
compiler system.

Once the necessary tools are installed, create a local branch of the
MySQL development tree on your machine using this procedure:

  1. To obtain a copy of the MySQL source code, you must create a new
     Bazaar branch. If you do not already have a Bazaar repository
     directory set up, you must initialize a new directory:

          shell> mkdir mysql-server
          shell> bzr init-repo --trees mysql-server

     This is a one-time operation.

  2. Assuming that you have an initialized repository directory, you
     can branch from the public MySQL server repositories to create a
     local source tree. To create a branch of a specific version:

          shell> cd mysql-server
          shell> bzr branch lp:mysql-server/5.0 mysql-5.0

     This is a one-time operation per source tree. You can branch the
     source trees for several versions of MySQL under the
     `mysql-server' directory.

  3. The initial download will take some time to complete, depending on
     the speed of your connection. Please be patient.  Once you have
     downloaded the first tree, additional trees should take
     significantly less time to download.

  4. When building from the Bazaar branch, you may want to create a
     copy of your active branch so that you can make configuration and
     other changes without affecting the original branch contents. You
     can achieve this by branching from the original branch:

          shell> bzr branch mysql-5.0 mysql-5.0-build

  5. To obtain changes made after you have set up the branch initially,
     update it using the `pull' option periodically. Use this command
     in the top-level directory of the local copy:

          shell> bzr pull

     You can examine the changeset comments for the tree by using the
     `log' option to `bzr':

          shell> bzr log

     You can also browse changesets, comments, and source code online
     at the Launchpad MySQL Server (http://launchpad.net/mysql-server)
     page.

     If you see diffs (changes) or code that you have a question about,
     do not hesitate to send email to the MySQL `internals' mailing
     list. See *Note mailing-lists::. If you think you have a better
     idea on how to do something, send an email message to the list
     with a patch.

After you have the local branch, you can build MySQL server from the
source code. On Windows, the build process is different from
Unix/Linux: see *Note windows-source-build::.

On Unix/Linux, use the `autoconf' system to create the `configure'
script so that you can configure the build environment before building.
The following example shows the typical commands required to build
MySQL from a source tree.

  1. Change location to the top-level directory of the source tree;
     replace `mysql-5.0' with the appropriate directory name.

          shell> cd mysql-5.0

  2. Prepare the source tree for configuration.

     You must separately configure the `BDB' and `InnoDB' storage
     engines. Run the following commands from the main source directory:

          shell> (cd bdb/dist; sh s_all)
          shell> (cd innobase; autoreconf --force --install)

     You can omit the previous commands if you do not require `BDB' or
     `InnoDB' support.

     Prepare the remainder of the source tree:

          shell> autoreconf --force --install

     As an alternative to the preceding `autoreconf' command, you can
     use `BUILD/autorun.sh', which acts as a shortcut for the following
     sequence of commands:

          shell> aclocal; autoheader
          shell> libtoolize --automake --force
          shell> automake --force --add-missing; autoconf
          shell> (cd bdb/dist; sh s_all)
          shell> (cd innobase; aclocal; autoheader; autoconf; automake)

     If you get some strange errors during this stage, verify that you
     have the correct version of `libtool' installed.

  3. Configure the source tree and compile MySQL:

          shell> ./configure  # Add your favorite options here
          shell> make

     For a description of some `configure' options, see *Note
     source-configuration-options::.

     A collection of configuration scripts is located in the `BUILD/'
     subdirectory. For example, you may find it more convenient to use
     the `BUILD/compile-pentium-debug' script than the preceding set of
     shell commands. To compile on a different architecture, modify the
     script by removing flags that are Pentium-specific, or use another
     script that may be more appropriate. These scripts are provided on
     an `as-is' basis. They are not supported and their contents may
     change from release to release.

  4. When the build is done, run `make install'.  Be careful with this
     on a production machine; the installation command may overwrite
     your live release installation. If you already have MySQL
     installed and do not want to overwrite it, run `./configure' with
     values for the `--prefix', `--with-tcp-port', and
     `--with-unix-socket-path' options different from those used by
     your production server.  For additional information about
     preventing multiple servers from interfering with each other, see
     *Note multiple-servers::.

  5. Play hard with your new installation. For example, try to make new
     features crash. Start by running `make test'. See *Note
     mysql-test-suite::.

  6. If you have gotten to the `make' stage, but the distribution does
     not compile, please enter the problem into our bugs database using
     the instructions given in *Note bug-reports::. If you have
     installed the latest versions of the required tools, and they
     crash trying to process our configuration files, please report
     that also.  However, if you get a `command not found' error or a
     similar problem for required tools, do not report it. Instead,
     make sure that all the required tools are installed and that your
     `PATH' variable is set correctly so that your shell can find them.


File: manual.info,  Node: source-configuration-options,  Next: compilation-problems,  Prev: installing-development-tree,  Up: source-installation

3.17.3 MySQL Source-Configuration Options
-----------------------------------------

The `configure' script provides a great deal of control over how you
configure a MySQL source distribution.  Typically, you do this using
options on the `configure' command line. For a full list of options
supported by `configure', run this command:

     shell> ./configure --help

You can also affect `configure' using certain environment variables. See
*Note environment-variables::.

The following table shows the available `configure' options.

*MySQL Source-Configuration Option Reference (`configure')*

Formats                Description            Default        IntroducedRemoved
`--bindir=DIR'         User executables       `EPREFIX/bin'          
`--build=BUILD'        Configure for          `guessed'              
                       building on BUILD                             
`--cache-file=FILE'    Cache test results in  `disabled'             
                       FILE                                          
`-C'                   Alias for              `'                     
                       `-cache-file=config.cache'                       
`--config-cache'                                                     
`--datadir=DIR'        Read-only              `PREFIX/share'         
                       architecture-independent                       
                       data                                          
`--disable-FEATURE'    Do not include FEATURE `'                     
`--disable-dependency-tracking'Disable dependency     `'                     
                       tracking                                      
`--disable-grant-options'Disable GRANT options  `'             5.0.34  
`--disable-largefile'  Omit support for       `'                     
                       large files                                   
`--disable-libtool-lock'Disable libtool lock   `'                     
`--disable-profiling'  Build a version        `'             5.0.37  5.0.45
                       without query                                 
                       profiling code                                
`--enable-FEATURE'     Enable FEATURE         `'                     
`--enable-assembler'   Use assembler          `'                     
                       versions of some                              
                       string functions if                           
                       available                                     
`--enable-dependency-tracking'Do not reject slow     `'                     
                       dependency extractors                         
`--enable-fast-install'Optimize for fast      `yes'                  
                       installation                                  
`--enable-local-infile'Enable LOCAL for LOAD  `disabled'             
                       DATA INFILE                                   
`--enable-shared'      Build shared libraries `yes'                  
`--enable-static'      Build static libraries `yes'                  
`--enable-thread-safe-client'Compile the client     `'                     
                       with threads                                  
`--exec-prefix=EPREFIX'Install                `'                     
                       architecture-dependent                        
                       files in EPREFIX                              
`-h'                   Display this help and  `'                     
                       exit                                          
`--help'                                                             
`--help=short'         Display options                               
                       specific to this                              
                       package                                       
`--help=recursive'     Display the short                             
                       help of all the                               
                       included packages                             
`--host=HOST'          Cross-compile to       `'                     
                       build programs to run                         
                       on HOST                                       
`--includedir=DIR'     C header files         `PREFIX/include'        
`--infodir=DIR'        Info documentation     `PREFIX/info'          
`--libdir=DIR'         Object code libraries  `EPREFIX/lib'          
`--libexecdir=DIR'     Program executables    `EPREFIX/libexec'        
`--localstatedir=DIR'  Modifiable             `PREFIX/var'           
                       single-machine data                           
`--mandir=DIR'         man documentation      `PREFIX/man'           
`-n'                   Do not create output   `'                     
                       files                                         
`--no-create'                                                        
`--oldincludedir=DIR'  C header files for     `/usr/include'         
                       non-gcc                                       
`--prefix=PREFIX'      Install                `'                     
                       architecture-independent                       
                       files in PREFIX                               
`--program-prefix=PREFIX'Prepend PREFIX to      `'                     
                       installed program                             
                       names                                         
`--program-suffix=SUFFIX'Append SUFFIX to       `'                     
                       installed program                             
                       names                                         
`--program-transform-name=PROGRAM'run sed PROGRAM on     `'                     
                       installed program                             
                       names                                         
`-q'                   Do not print           `'                     
                       `checking...' messages                        
`--quiet'                                                            
`--sbindir=DIR'        System administrative  `EPREFIX/sbin'         
                       executables                                   
`--sharedstatedir=DIR' Modifiable             `PREFIX/com'           
                       architecture-independent                       
                       data                                          
`--srcdir=DIR'         Find the sources in    `configure             
                       DIR                    directory or           
                                              ..'                    
`--sysconfdir=DIR'     Read-only              `PREFIX/etc'           
                       single-machine data                           
`--target=TARGET'      Configure for          `'                     
                       building compilers                            
                       for TARGET                                    
`-V'                   Display version        `'                     
                       information and exit                          
`--version'                                                          
`--with-PACKAGE'       Use PACKAGE            `'                     
`--with-archive-storage-engine'Enable the Archive     `no'                   
                       Storage Engine                                
`--with-berkeley-db'   Use BerkeleyDB         `no'                   
                       located in DIR                                
`--with-berkeley-db-includes'Find Berkeley DB       `'                     
                       headers in DIR                                
`--with-berkeley-db-libs'Find Berkeley DB       `'                     
                       libraries in DIR                              
`--with-big-tables'    Support tables with    `'             5.0.4   
                       more than 4 G rows                            
                       even on 32 bit                                
                       platforms                                     
`--with-blackhole-storage-engine'Enable the Blackhole   `no'           5.0.4   
                       Storage Engine                                
`--with-charset'       Default character set  `'                     
`--with-client-ldflags'Extra linking          `'                     
                       arguments for clients                         
`--with-collation'     Default collation      `'                     
`--with-comment'       Comment about          `'                     
                       compilation                                   
                       environment                                   
`--with-csv-storage-engine'Enable the CSV         `yes'                  
                       Storage Engine                                
`--with-darwin-mwcc'   Use Metrowerks         `'             5.0.6   
                       CodeWarrior wrappers                          
                       on OS X/Darwin                                
`--with-embedded-privilege-control'Build parts to check   `'                     
                       user's privileges                             
                       (only affects                                 
                       embedded library)                             
`--with-embedded-server'Build the embedded     `'                     
                       server                                        
`--with-example-storage-engine'Enable the Example     `no'                   
                       Storage Engine                                
`--with-extra-charsets'Use charsets in        `'                     
                       addition to default                           
`--with-gnu-ld'        Assume the C compiler  `no'                   
                       uses GNU ld                                   
`--with-isam'          Enable the ISAM table  `'                     5.0.2
                       type                                          
`--with-lib-ccflags'   Extra CC options for   `'                     
                       libraries                                     
`--with-libwrap=DIR'   Compile in libwrap     `'                     
                       (tcp_wrappers) support                        
`--with-low-memory'    Try to use less        `'                     
                       memory to compile to                          
                       avoid memory                                  
                       limitations                                   
`--with-machine-type'  Set the machine type,  `'             5.0.44  
                       like "powerpc"                                
`--with-max-indexes=N' Sets the maximum       `64'                   
                       number of indexes per                         
                       table                                         
`--with-mit-threads'   Always use included    `'                     5.0.4
                       thread lib                                    
`--with-mysqld-ldflags'Extra linking          `'                     
                       arguments for mysqld                          
`--with-mysqld-libs'   Extra libraries to     `'             5.0.44  
                       link with for mysqld                          
`--with-mysqld-user'   What user the mysqld   `'                     
                       daemon shall be run as                        
`--with-mysqlfs'       Include the            `'                     5.0.3
                       corba-based MySQL                             
                       file system                                   
`--with-mysqlmanager'  Build the              `Build if              
                       mysqlmanager binary    server is              
                                              built'                 
`--with-named-curses-libs'Use specified curses   `'                     
                       libraries                                     
`--with-named-thread-libs'Use specified thread   `'                     
                       libraries                                     
`--with-ndb-ccflags'   Extra CC options for   `'             5.0.3   
                       ndb compile                                   
`--with-ndb-docs'      Include the NDB        `'                     
                       Cluster ndbapi and                            
                       mgmapi documentation                          
`--with-ndb-port'      Port for NDB Cluster   `'                     
                       management server                             
`--with-ndb-port-base' Port for NDB Cluster   `'             5.0.3   
                       management server                             
`--with-ndb-sci=DIR'   Provide MySQL with a   `'                     
                       custom location of                            
                       sci library                                   
`--with-ndb-shm'       Include the NDB        `'                     5.0.2
                       Cluster shared memory                         
                       transporter                                   
`--with-ndb-test'      Include the NDB        `'                     
                       Cluster ndbapi test                           
                       programs                                      
`--with-ndbcluster'    Include the NDB        `no'                   
                       Cluster table handler                         
`--with-openssl=DIR'   Include the OpenSSL    `'                     
                       support                                       
`--with-openssl-includes'Find OpenSSL headers   `'                     
                       in DIR                                        
`--with-openssl-libs'  Find OpenSSL           `'                     
                       libraries in DIR                              
`--with-other-libc=DIR'Link against libc and  `'                     
                       other standard                                
                       libraries installed in                        
                       the specified                                 
                       nonstandard location                          
`--with-pic'           Try to use only        `Use both'             
                       PIC/non-PIC objects                           
`--with-pstack'        Use the pstack         `'                     
                       backtrace library                             
`--with-pthread'       Force use of pthread   `'                     
                       library                                       
`--with-raid'          Enable RAID Support    `'                     5.0.3
`--with-server-suffix' Append value to the    `'                     
                       version string                                
`--with-system-type'   Set the system type,   `'             5.0.44  
                       like "sun-solaris10"                          
`--with-tags'          Include additional     `automatic'            
                       configurations                                
`--with-tcp-port'      Which port to use for  `3306'                 
                       MySQL services                                
`--with-unix-socket-path'Where to put the       `'                     
                       unix-domain socket                            
`--with-vio'           Include the Virtual    `'                     5.0.2
                       IO support                                    
`--with-yassl'         Include the yaSSL      `'             5.0.6   
                       support                                       
`--with-zlib-dir=no|bundled|DIR'Provide MySQL with a   `'                     
                       custom location of                            
                       compression library                           
`--without-PACKAGE'    Do not use PACKAGE     `'                     
`--without-bench'      Skip building of the   `'                     
                       benchmark suite                               
`--without-debug'      Build a production     `'                     
                       version without                               
                       debugging code                                
`--without-docs'       Skip building of the   `'                     
                       documentation                                 
`--without-extra-tools'Skip building          `'                     
                       utilities in the                              
                       tools directory                               
`--without-geometry'   Do not build           `'                     
                       geometry-related parts                        
`--without-innodb'     Do not include the     `'                     5.0.48
                       InnoDB table handler                          
`--without-libedit'    Use system libedit     `'                     
                       instead of bundled                            
                       copy                                          
`--without-man'        Skip building of the   `'                     
                       man pages                                     
`--without-ndb-debug'  Disable special ndb    `'             5.0.3   
                       debug features                                
`--without-query-cache'Do not build query     `'                     
                       cache                                         
`--without-readline'   Use system readline    `'                     
                       instead of bundled                            
                       copy                                          
`--without-server'     Only build the client  `'                     
`--without-uca'        Skip building of the   `'             5.0.3   
                       national Unicode                              
                       collations                                    

Some of the `configure' options available are described here. For
options that may be of use if you have difficulties building MySQL, see
*Note compilation-problems::.

Many options configure compile-time defaults that can be overridden at
server startup. For example, the `--prefix', `--with-tcp-port', and
`with-unix-socket-path' options that configure the default installation
base directory location, TCP/IP port number, and Unix socket file can
be changed at server startup with the `--basedir', `--port', and
`--socket' options for *Note `mysqld': mysqld.

   *  To compile just the MySQL client libraries and client programs
     and not the server, use the `--without-server' option:

          shell> ./configure --without-server

     If you have no C++ compiler, some client programs such as *Note
     `mysql': mysql. cannot be compiled because they require C++. In
     this case, you can remove the code in `configure' that tests for
     the C++ compiler and then run `./configure' with the
     `--without-server' option. The compile step should still try to
     build all clients, but you can ignore any warnings about files
     such as `mysql.cc'. (If `make' stops, try `make -k' to tell it to
     continue with the rest of the build even if errors occur.)

   *  To build the embedded MySQL library (`libmysqld.a'), use the
     `--with-embedded-server' option.

   *  To place your log files and database directories elsewhere than
     under `/usr/local/var', use a `configure' command something like
     one of these:

          shell> ./configure --prefix=/usr/local/mysql
          shell> ./configure --prefix=/usr/local \
                     --localstatedir=/usr/local/mysql/data

     The first command changes the installation prefix so that
     everything is installed under `/usr/local/mysql' rather than the
     default of `/usr/local'. The second command preserves the default
     installation prefix, but overrides the default location for
     database directories (normally `/usr/local/var') and changes it to
     `/usr/local/mysql/data'.

     You can also specify the installation directory and data directory
     locations at server startup time by using the `--basedir' and
     `--datadir' options. These can be given on the command line or in
     an MySQL option file, although it is more common to use an option
     file. See *Note option-files::.

   *  The `--with-tcp-port' option specifies the port number on which
     the server listens for TCP/IP connections. The default is port
     3306. To listen on a different port, use a `configure' command
     like this:

          shell> ./configure --with-tcp-port=3307

   *  On Unix, if you want the MySQL socket file location to be
     somewhere other than the default location (normally in the
     directory `/tmp' or `/var/run'), use a `configure' command like
     this:

          shell> ./configure \
                     --with-unix-socket-path=/usr/local/mysql/tmp/mysql.sock

     The socket file name must be an absolute path name. You can also
     change the location of `mysql.sock' at server startup by using a
     MySQL option file. See *Note problems-with-mysql-sock::.

   *  To compile statically linked programs (for example, to make a
     binary distribution, to get better performance, or to work around
     problems with some Red Hat Linux distributions), run `configure'
     like this:

          shell> ./configure --with-client-ldflags=-all-static \
                     --with-mysqld-ldflags=-all-static

   * If you are using `gcc' and do not have `libg++' or `libstdc++'
     installed, you can tell `configure' to use `gcc' as your C++
     compiler:

          shell> CC=gcc CXX=gcc ./configure

     When you use `gcc' as your C++ compiler, it does not attempt to
     link in `libg++' or `libstdc++'. This may be a good thing to do
     even if you have those libraries installed. Some versions of them
     have caused strange problems for MySQL users in the past.

     The following list indicates some compilers and environment
     variable settings that are commonly used with each one.

        * `gcc' 2.7.2:

               CC=gcc CXX=gcc CXXFLAGS="-O3 -felide-constructors"

        * `gcc' 2.95.2:

               CFLAGS="-O3 -mpentiumpro" CXX=gcc CXXFLAGS="-O3 -mpentiumpro \
               -felide-constructors -fno-exceptions -fno-rtti"

     In most cases, you can get a reasonably optimized MySQL binary by
     using the options from the preceding list and adding the following
     options to the `configure' line:

          --prefix=/usr/local/mysql --enable-assembler \
          --with-mysqld-ldflags=-all-static

     The full `configure' line would, in other words, be something like
     the following for all recent `gcc' versions:

          CFLAGS="-O3 -mpentiumpro" CXX=gcc CXXFLAGS="-O3 -mpentiumpro \
          -felide-constructors -fno-exceptions -fno-rtti" ./configure \
          --prefix=/usr/local/mysql --enable-assembler \
          --with-mysqld-ldflags=-all-static

     The binaries we provide on the MySQL Web site at
     `http://dev.mysql.com/downloads/' are all compiled with full
     optimization and should work well for most users. See *Note
     binary-installation::.

   * If the build fails and produces errors about your compiler or
     linker not being able to create the shared library
     `libmysqlclient.so.N' (where N is a version number), you can work
     around this problem by giving the `--disable-shared' option to
     `configure'. In this case, `configure' does not build a shared
     `libmysqlclient.so.N' library.

   *  By default, MySQL uses the `latin1' (cp1252 West European)
     character set. To change the default set, use the `--with-charset'
     option:

          shell> ./configure --with-charset=CHARSET

     CHARSET may be one of `binary', `armscii8', `ascii', `big5',
     `cp1250', `cp1251', `cp1256', `cp1257', `cp850', `cp852', `cp866',
     `cp932', `dec8', `eucjpms', `euckr', `gb2312', `gbk', `geostd8',
     `greek', `hebrew', `hp8', `keybcs2', `koi8r', `koi8u', `latin1',
     `latin2', `latin5', `latin7', `macce', `macroman', `sjis', `swe7',
     `tis620', `ucs2', `ujis', `utf8'. (Additional character sets might
     be available. Check the output from `./configure --help' for the
     current list.)

     The default collation may also be specified. MySQL uses the
     `latin1_swedish_ci' collation by default. To change this, use the
     `--with-collation' option:

          shell> ./configure --with-collation=COLLATION

     To change both the character set and the collation, use both the
     `--with-charset' and `--with-collation' options.  The collation
     must be a legal collation for the character set.  (Use the *Note
     `SHOW COLLATION': show-collation.  statement to determine which
     collations are available for each character set.)

     With the `configure' option `--with-extra-charsets=LIST', you can
     define which additional character sets should be compiled into the
     server. LIST is one of the following:

        * A list of character set names separated by spaces

        * `complex' to include all character sets that can't be
          dynamically loaded

        * `all' to include all character sets into the binaries

     Clients that want to convert characters between the server and the
     client should use the `SET NAMES' statement. See *Note
     charset-connection::.

   *  To configure MySQL with debugging code, use the `--with-debug'
     option:

          shell> ./configure --with-debug

     This causes a safe memory allocator to be included that can find
     some errors and that provides output about what is happening. See
     MySQL Internals: Porting
     (http://forge.mysql.com/wiki/MySQL_Internals_Porting).

     As of MySQL 5.0.25, using `--with-debug' to configure MySQL with
     debugging support enables you to use the
     `--debug="d,parser_debug"' option when you start the server. This
     causes the Bison parser that is used to process SQL statements to
     dump a parser trace to the server's standard error output.
     Typically, this output is written to the error log.

   *  If your client programs are using threads, you must compile a
     thread-safe version of the MySQL client library with the
     `--enable-thread-safe-client' configure option. This creates a
     `libmysqlclient_r' library with which you should link your
     threaded applications. See *Note threaded-clients::.

   *  Some features require that the server be built with compression
     library support, such as the `COMPRESS()' and `UNCOMPRESS()'
     functions, and compression of the client/server protocol. The
     `--with-zlib-dir=no|bundled|DIR' option provides control over
     compression library support. The value `no' explicitly disables
     compression support. `bundled' causes the `zlib' library bundled
     in the MySQL sources to be used. A DIR path name specifies the
     directory in which to find the compression library sources.

   *  It is possible to build MySQL 5.0 with large table support using
     the `--with-big-tables' option, beginning with MySQL 5.0.4.

     This option causes the variables that store table row counts to be
     declared as `unsigned long long' rather than `unsigned long'. This
     enables tables to hold up to approximately 1.844E+19 ((2^32)^2)
     rows rather than 2^32 (~4.295E+09) rows. Previously it was
     necessary to pass `-DBIG_TABLES' to the compiler manually in order
     to enable this feature.

   *  Run `configure' with the `--disable-grant-options' option to
     cause the `--bootstrap', `--skip-grant-tables', and `--init-file'
     options for *Note `mysqld': mysqld. to be disabled. For Windows,
     the `configure.js' script recognizes the `DISABLE_GRANT_OPTIONS'
     flag, which has the same effect. The capability is available as of
     MySQL 5.0.34.

   *  In MySQL Community Server, this option enables the statement
     profiling capability exposed by the *Note `SHOW PROFILE':
     show-profile. and *Note `SHOW PROFILES': show-profiles.
     statements. (See *Note show-profiles::.) The option was added in
     MySQL 5.0.37.

   * See *Note operating-system-specific-notes::, for options that
     pertain to particular operating systems.

   * See *Note secure-using-ssl::, for options that pertain to
     configuring MySQL to support secure (encrypted) connections.


File: manual.info,  Node: compilation-problems,  Next: compile-and-link-options,  Prev: source-configuration-options,  Up: source-installation

3.17.4 Dealing with Problems Compiling MySQL
--------------------------------------------

All MySQL programs compile cleanly for us with no warnings on Solaris
or Linux using `gcc'. On other systems, warnings may occur due to
differences in system include files. For other problems, check the
following list.

The solution to many problems involves reconfiguring. If you do need to
reconfigure, take note of the following:

   * If `configure' is run after it has previously been run, it may use
     information that was gathered during its previous invocation. This
     information is stored in `config.cache'. When `configure' starts
     up, it looks for that file and reads its contents if it exists, on
     the assumption that the information is still correct. That
     assumption is invalid when you reconfigure.

   * Each time you run `configure', you must run `make' again to
     recompile. However, you may want to remove old object files from
     previous builds first because they were compiled using different
     configuration options.

To prevent old configuration information or object files from being
used, run these commands before re-running `configure':

     shell> rm config.cache
     shell> make clean

Alternatively, you can run `make distclean'.

The following list describes some of the problems that have been found
to occur most often when compiling MySQL:

   *  If you get errors such as the ones shown here when compiling
     `sql_yacc.cc', you probably have run out of memory or swap space:

          Internal compiler error: program cc1plus got fatal signal 11
          Out of virtual memory
          Virtual memory exhausted

     The problem is that `gcc' requires a huge amount of memory to
     compile `sql_yacc.cc' with inline functions. Try running
     `configure' with the `--with-low-memory' option:

          shell> ./configure --with-low-memory

     This option causes `-fno-inline' to be added to the compile line
     if you are using `gcc' and `-O0' if you are using something else.
     You should try the `--with-low-memory' option even if you have so
     much memory and swap space that you think you can't possibly have
     run out. This problem has been observed to occur even on systems
     with generous hardware configurations, and the `--with-low-memory'
     option usually fixes it.

   * By default, `configure' picks `c++' as the compiler name and GNU
     `c++' links with `-lg++'. If you are using `gcc', that behavior
     can cause problems during configuration such as this:

          configure: error: installation or configuration problem:
          C++ compiler cannot create executables.

     You might also observe problems during compilation related to
     `g++', `libg++', or `libstdc++'.

     One cause of these problems is that you may not have `g++', or you
     may have `g++' but not `libg++', or `libstdc++'. Take a look at the
     `config.log' file. It should contain the exact reason why your C++
     compiler did not work. To work around these problems, you can use
     `gcc' as your C++ compiler. Try setting the environment variable
     `CXX' to `"gcc -O3"'. For example:

          shell> CXX="gcc -O3" ./configure

     This works because `gcc' compiles C++ source files as well as
     `g++' does, but does not link in `libg++' or `libstdc++' by
     default.

     Another way to fix these problems is to install `g++', `libg++',
     and `libstdc++'. However, do not use `libg++' or `libstdc++' with
     MySQL because this only increases the binary size of *Note
     `mysqld': mysqld. without providing any benefits. Some versions of
     these libraries have also caused strange problems for MySQL users
     in the past.

   * To define flags to be used by your C or C++ compilers, specify
     them using the `CFLAGS' and `CXXFLAGS' environment variables. You
     can also specify the compiler names this way using `CC' and `CXX'.
     For example:

          shell> CC=gcc
          shell> CFLAGS=-O3
          shell> CXX=gcc
          shell> CXXFLAGS=-O3
          shell> export CC CFLAGS CXX CXXFLAGS

     To see what flags you might need to specify, invoke *Note
     `mysql_config': mysql-config. with the `--cflags' option.

   * If you get errors such as those shown here when compiling *Note
     `mysqld': mysqld, `configure' did not correctly detect the type of
     the last argument to `accept()', `getsockname()', or
     `getpeername()':

          cxx: Error: mysqld.cc, line 645: In this statement, the referenced
               type of the pointer value ''length'' is ''unsigned long'',
               which is not compatible with ''int''.
          new_sock = accept(sock, (struct sockaddr *)&cAddr, &length);

     To fix this, edit the `config.h' file (which is generated by
     `configure'). Look for these lines:

          /* Define as the base type of the last arg to accept */
          #define SOCKET_SIZE_TYPE XXX

     Change `XXX' to `size_t' or `int', depending on your operating
     system.  (You must do this each time you run `configure' because
     `configure' regenerates `config.h'.)

   * If your compile fails with errors such as any of the following,
     you must upgrade your version of `make' to GNU `make':

          make: Fatal error in reader: Makefile, line 18:
          Badly formed macro assignment

     Or:

          make: file `Makefile' line 18: Must be a separator (:

     Or:

          pthread.h: No such file or directory

     Solaris and FreeBSD are known to have troublesome `make' programs.

     GNU `make' 3.75 is known to work.

   * The `sql_yacc.cc' file is generated from `sql_yacc.yy'. Normally,
     the build process does not need to create `sql_yacc.cc' because
     MySQL comes with a pregenerated copy. However, if you do need to
     re-create it, you might encounter this error:

          "sql_yacc.yy", line XXX fatal: default action causes potential...

     This is a sign that your version of `yacc' is deficient. You
     probably need to install `bison' (the GNU version of `yacc') and
     use that instead.

     Versions of `bison' older than 1.75 may report this error:

          sql_yacc.yy:#####: fatal error: maximum table size (32767) exceeded

     The maximum table size is not actually exceeded; the error is
     caused by bugs in older versions of `bison'.

   * On Debian Linux 3.0, you need to install `gawk' instead of the
     default `mawk' if you want to compile MySQL with Berkeley DB
     support.

   * If you get a compilation error on Linux (for example, SuSE Linux
     8.1 or Red Hat Linux 7.3) similar to the following one, you
     probably do not have `g++' installed:

          libmysql.c:1329: warning: passing arg 5 of `gethostbyname_r' from
          incompatible pointer type
          libmysql.c:1329: too few arguments to function `gethostbyname_r'
          libmysql.c:1329: warning: assignment makes pointer from integer
          without a cast
          make[2]: *** [libmysql.lo] Error 1

     By default, the `configure' script attempts to determine the
     correct number of arguments by using `g++' (the GNU C++ compiler).
     This test yields incorrect results if `g++' is not installed.
     There are two ways to work around this problem:

        * Make sure that the GNU C++ `g++' is installed. On some Linux
          distributions, the required package is called `gpp'; on
          others, it is named `gcc-c++'.

        * Use `gcc' as your C++ compiler by setting the `CXX'
          environment variable to `gcc':

               export CXX="gcc"

     You must run `configure' again after making either of those
     changes.

For information about acquiring or updating tools, see the system
requirements in *Note source-installation::.


File: manual.info,  Node: compile-and-link-options,  Prev: compilation-problems,  Up: source-installation

3.17.5 Compiling and Linking an Optimized `mysqld' Server
---------------------------------------------------------

Most of the following tests were performed on Linux with the MySQL
benchmarks, but they should give some indication for other operating
systems and workloads.

You obtain the fastest executables when you link with `-static'.

By using better compiler and compilation options, you can obtain a 10%
to 30% speed increase in applications. This is particularly important
if you compile the MySQL server yourself.

When we tested both the Cygnus CodeFusion and Fujitsu compilers,
neither was sufficiently bug-free to enable MySQL to be compiled with
optimizations enabled.

The standard MySQL binary distributions are compiled with support for
all character sets. When you compile MySQL yourself, you should include
support only for the character sets that you are going to use. This is
controlled by the `--with-charset' option to `configure'.

Here is a list of some measurements that we have made:

   * If you link dynamically (without `-static'), the result is 13%
     slower on Linux. Note that you still can use a dynamically linked
     MySQL library for your client applications. It is the server that
     is most critical for performance.

   * For a connection from a client to a server running on the same
     host, if you connect using TCP/IP rather than a Unix socket file,
     performance is 7.5% slower. (On Unix, if you connect to the host
     name `localhost', MySQL uses a socket file by default.)

   * For TCP/IP connections from a client to a server, connecting to a
     remote server on another host is 8% to 11% slower than connecting
     to a server on the same host, even for connections faster than
     100Mb/s Ethernet.

   * When running our benchmark tests using secure connections (all
     data encrypted with internal SSL support) performance was 55%
     slower than with unencrypted connections.

   * If you compile with `--with-debug=full', most queries are 20%
     slower. Some queries may take substantially longer; for example,
     the MySQL benchmarks run 35% slower. If you use `--with-debug'
     (without `=full'), the speed decrease is only 15%. For a version
     of *Note `mysqld': mysqld. that has been compiled with
     `--with-debug=full', you can disable memory checking at runtime by
     starting it with the `--skip-safemalloc' option. The execution
     speed should then be close to that obtained when configuring with
     `--with-debug'.

   * On a Sun UltraSPARC-IIe, a server compiled with Forte 5.0 is 4%
     faster than one compiled with `gcc' 3.2.

   * On a Sun UltraSPARC-IIe, a server compiled with Forte 5.0 is 4%
     faster in 32-bit mode than in 64-bit mode.

   * Compiling with `gcc' 2.95.2 for UltraSPARC with the `-mcpu=v8
     -Wa,-xarch=v8plusa' options gives 4% better performance.

   * Compiling on Linux-x86 using `gcc' without frame pointers
     (`-fomit-frame-pointer' or `-fomit-frame-pointer -ffixed-ebp')
     makes *Note `mysqld': mysqld. 1% to 4% faster.


File: manual.info,  Node: postinstallation,  Next: upgrading-downgrading,  Prev: source-installation,  Up: installing

3.18 Postinstallation Setup and Testing
=======================================

* Menu:

* unix-postinstallation::        Unix Postinstallation Procedures
* default-privileges::           Securing the Initial MySQL Accounts

After installing MySQL, there are some issues that you should address.
For example, on Unix, you should initialize the data directory and
create the MySQL grant tables. On all platforms, an important security
concern is that the initial accounts in the grant tables have no
passwords. You should assign passwords to prevent unauthorized access
to the MySQL server. Optionally, you can create time zone tables to
enable recognition of named time zones.

The following sections include postinstallation procedures that are
specific to Windows systems and to Unix systems. Another section, *Note
starting-server::, applies to all platforms; it describes what to do if
you have trouble getting the server to start. *Note
default-privileges::, also applies to all platforms. You should follow
its instructions to make sure that you have properly protected your
MySQL accounts by assigning passwords to them.

When you are ready to create additional user accounts, you can find
information on the MySQL access control system and account management
in *Note privilege-system::, and *Note user-account-management::.


File: manual.info,  Node: unix-postinstallation,  Next: default-privileges,  Prev: postinstallation,  Up: postinstallation

3.18.1 Unix Postinstallation Procedures
---------------------------------------

* Menu:

* mysql-install-db-problems::    Problems Running `mysql_install_db'
* automatic-start::              Starting and Stopping MySQL Automatically
* starting-server::              Starting and Troubleshooting the MySQL Server

After installing MySQL on Unix, you must initialize the grant tables,
start the server, and make sure that the server works satisfactorily.
You may also wish to arrange for the server to be started and stopped
automatically when your system starts and stops. You should also assign
passwords to the accounts in the grant tables.

On Unix, the grant tables are set up by the *Note `mysql_install_db':
mysql-install-db. program. For some installation methods, this program
is run for you automatically if an existing database cannot be found.

   * If you install MySQL on Linux using RPM distributions, the server
     RPM runs *Note `mysql_install_db': mysql-install-db.

   * If you install MySQL on Mac OS X using a PKG distribution, the
     installer runs *Note `mysql_install_db': mysql-install-db.

For other platforms and installation types, including generic binary
and source installs, you will need to run *Note `mysql_install_db':
mysql-install-db. yourself.

The following procedure describes how to initialize the grant tables
(if that has not previously been done) and start the server. It also
suggests some commands that you can use to test whether the server is
accessible and working properly. For information about starting and
stopping the server automatically, see *Note automatic-start::.

After you complete the procedure and have the server running, you
should assign passwords to the accounts created by *Note
`mysql_install_db': mysql-install-db. and perhaps tighten access to
test databases. For instructions, see *Note default-privileges::.

In the examples shown here, the server runs under the user ID of the
`mysql' login account. This assumes that such an account exists. Either
create the account if it does not exist, or substitute the name of a
different existing login account that you plan to use for running the
server.

  1. Change location into the top-level directory of your MySQL
     installation, represented here by BASEDIR:

          shell> cd BASEDIR

     BASEDIR is the installation directory for your MySQL instance. It
     is likely to be something like `/usr/local/mysql' or `/usr/local'.
     The following steps assume that you have changed location to this
     directory.

     You will find several files and subdirectories in the BASEDIR
     directory. The most important for installation purposes are the
     `bin' and `scripts' subdirectories:

        * The `bin' directory contains client programs and the server.
          You should add the full path name of this directory to your
          `PATH' environment variable so that your shell finds the MySQL
          programs properly. See *Note environment-variables::.

          For some distribution types, *Note `mysqld': mysqld. is in
          the `libexec' directory.

        * The `scripts' directory contains the *Note
          `mysql_install_db': mysql-install-db. script used to
          initialize the `mysql' database containing the grant tables
          that store the server access permissions.

          For some distribution types, *Note `mysql_install_db':
          mysql-install-db. is in the `bin' directory.

  2. If necessary, ensure that the distribution contents are accessible
     to `mysql'. If you unpacked the distribution as `mysql', no
     further action is required. If you unpacked the distribution as
     `root', its contents will be owned by `root'. Change its ownership
     to `mysql' by executing the following commands as `root' in the
     installation directory:

          shell> chown -R mysql .
          shell> chgrp -R mysql .

     The first command changes the owner attribute of the files to the
     `mysql' user. The second changes the group attribute to the
     `mysql' group.

  3. If necessary, run the *Note `mysql_install_db': mysql-install-db.
     program to set up the initial MySQL grant tables containing the
     privileges that determine how users are permitted to connect to
     the server. You will need to do this if you used a distribution
     type for which the installation procedure does not run the program
     for you.

     Typically, *Note `mysql_install_db': mysql-install-db. needs to be
     run only the first time you install MySQL, so you can skip this
     step if you are upgrading an existing installation, However, *Note
     `mysql_install_db': mysql-install-db. does not overwrite any
     existing privilege tables, so it should be safe to run in any
     circumstances.

     The exact location of *Note `mysql_install_db': mysql-install-db.
     will depends on the layout for your given installation. To
     initialize the grant tables, use one of the following commands,
     depending on whether *Note `mysql_install_db': mysql-install-db.
     is located in the `bin' or `scripts' directory:

          shell> bin/mysql_install_db --user=mysql
          shell> scripts/mysql_install_db --user=mysql

     It might be necessary to specify other options such as `--basedir'
     or `--datadir' if *Note `mysql_install_db': mysql-install-db. does
     not identify the correct locations for the installation directory
     or data directory. For example:

          shell> bin/mysql_install_db --user=mysql \
                   --basedir=/opt/mysql/mysql \
                   --datadir=/opt/mysql/mysql/data

     The *Note `mysql_install_db': mysql-install-db. script creates the
     server's data directory with `mysql' as the owner. Under the data
     directory, it creates directories for the `mysql' database that
     holds the grant tables and the `test' database that you can use to
     test MySQL. The script also creates privilege table entries for
     `root' and anonymous-user accounts. The accounts have no passwords
     initially.  *Note default-privileges::, describes the initial
     privileges. Briefly, these privileges permit the MySQL `root' user
     to do anything, and permit anybody to create or use databases with
     a name of `test' or starting with `test_'.

     It is important to make sure that the database directories and
     files are owned by the `mysql' login account so that the server
     has read and write access to them when you run it later. To ensure
     this, the `--user' option should be used as shown if you run *Note
     `mysql_install_db': mysql-install-db. as `root'. Otherwise, you
     should execute the script while logged in as `mysql', in which
     case you can omit the `--user' option from the command.

     *Note `mysql_install_db': mysql-install-db. creates several tables
     in the `mysql' database, including `user', `db', `host',
     `tables_priv', `columns_priv', `func', and others. See *Note
     privilege-system::, for a complete listing and description of
     these tables.

     If you do not want to have the `test' database, you can remove it
     after starting the server, using the instructions in *Note
     default-privileges::.

     If you have trouble with *Note `mysql_install_db':
     mysql-install-db.  at this point, see *Note
     mysql-install-db-problems::.

  4. Most of the MySQL installation can be owned by `root' if you like.
     The exception is that the data directory must be owned by `mysql'.
     To accomplish this, run the following commands as `root' in the
     installation directory. For some distribution types, the data
     directory might be named `var' rather than `data'; adjust the
     second command accordingly.

          shell> chown -R root .
          shell> chown -R mysql data

  5. If the plugin directory (the directory named by the `plugin_dir'
     system variable) is writable by the server, it may be possible for
     a user to write executable code to a file in the directory using
     *Note `SELECT ... INTO DUMPFILE': select-into. This can be
     prevented by making `plugin_dir' read only to the server or by
     setting `--secure-file-priv' to a directory where *Note `SELECT':
     select. writes can be made safely.

  6. If you installed MySQL using a source distribution, you may want
     to optionally copy one of the provided configuration files from
     the `support-files' directory into your `/etc' directory. There are
     different sample configuration files for different use cases,
     server types, and CPU and RAM configurations. If you want to use
     one of these standard files, you should copy it to `/etc/my.cnf',
     or `/etc/mysql/my.cnf' and edit and check the configuration before
     starting your MySQL server for the first time.

     If you do not copy one of the standard configuration files, the
     MySQL server will be started with the default settings.

     If you want MySQL to start automatically when you boot your
     machine, you can copy `support-files/mysql.server' to the location
     where your system has its startup files. More information can be
     found in the `mysql.server' script itself, and in *Note
     automatic-start::.

  7. Start the MySQL server:

          shell> bin/mysqld_safe --user=mysql &

     It is important that the MySQL server be run using an unprivileged
     (non-`root') login account. To ensure this, the `--user' option
     should be used as shown if you run *Note `mysqld_safe':
     mysqld-safe. as system `root'. Otherwise, you should execute the
     script while logged in to the system as `mysql', in which case you
     can omit the `--user' option from the command.

     Further instructions for running MySQL as an unprivileged user are
     given in *Note changing-mysql-user::.

     If the command fails immediately and prints `mysqld ended', you
     can find some information in the `HOST_NAME.err' file in the data
     directory.

     If you neglected to create the grant tables by running *Note
     `mysql_install_db': mysql-install-db. before proceeding to this
     step, the following message appears in the error log file when you
     start the server:

          mysqld: Can't find file: 'host.frm'

     This error also occurs if you run *Note `mysql_install_db':
     mysql-install-db. as `root' without the `--user' option. Remove
     the `data' directory and run *Note `mysql_install_db':
     mysql-install-db. with the `--user' option as described previously.

     If you have other problems starting the server, see *Note
     starting-server::. For more information about *Note `mysqld_safe':
     mysqld-safe, see *Note mysqld-safe::.

  8. Use *Note `mysqladmin': mysqladmin. to verify that the server is
     running. The following commands provide simple tests to check
     whether the server is up and responding to connections:

          shell> bin/mysqladmin version
          shell> bin/mysqladmin variables

     The output from *Note `mysqladmin version': mysqladmin. varies
     slightly depending on your platform and version of MySQL, but
     should be similar to that shown here:

          shell> bin/mysqladmin version
          mysqladmin  Ver 14.12 Distrib 5.0.95, for pc-linux-gnu on i686
          ...

          Server version          5.0.95
          Protocol version        10
          Connection              Localhost via UNIX socket
          UNIX socket             /var/lib/mysql/mysql.sock
          Uptime:                 14 days 5 hours 5 min 21 sec

          Threads: 1  Questions: 366  Slow queries: 0
          Opens: 0  Flush tables: 1  Open tables: 19
          Queries per second avg: 0.000

     To see what else you can do with *Note `mysqladmin': mysqladmin,
     invoke it with the `--help' option.

  9. Verify that you can shut down the server:

          shell> bin/mysqladmin -u root shutdown

 10. Verify that you can start the server again. Do this by using *Note
     `mysqld_safe': mysqld-safe. or by invoking *Note `mysqld': mysqld.
     directly. For example:

          shell> bin/mysqld_safe --user=mysql --log &

     If *Note `mysqld_safe': mysqld-safe. fails, see *Note
     starting-server::.

 11. Run some simple tests to verify that you can retrieve information
     from the server. The output should be similar to what is shown
     here:

          shell> bin/mysqlshow
          +--------------------+
          |     Databases      |
          +--------------------+
          | information_schema |
          | mysql              |
          | test               |
          +--------------------+

          shell> bin/mysqlshow mysql
          Database: mysql
          +---------------------------+
          |          Tables           |
          +---------------------------+
          | columns_priv              |
          | db                        |
          | func                      |
          | help_category             |
          | help_keyword              |
          | help_relation             |
          | help_topic                |
          | host                      |
          | proc                      |
          | procs_priv                |
          | tables_priv               |
          | time_zone                 |
          | time_zone_leap_second     |
          | time_zone_name            |
          | time_zone_transition      |
          | time_zone_transition_type |
          | user                      |
          +---------------------------+

          shell> bin/mysql -e "SELECT Host,Db,User FROM db" mysql
          +------+--------+------+
          | host | db     | user |
          +------+--------+------+
          | %    | test   |      |
          | %    | test_% |      |
          +------+--------+------+

 12. There is a benchmark suite in the `sql-bench' directory (under the
     MySQL installation directory) that you can use to compare how MySQL
     performs on different platforms. The benchmark suite is written in
     Perl. It requires the Perl DBI module that provides a
     database-independent interface to the various databases, and some
     other additional Perl modules:

          DBI
          DBD::mysql
          Data::Dumper
          Data::ShowTable

     These modules can be obtained from CPAN (`http://www.cpan.org/').
     See also *Note perl-installation::.

     The `sql-bench/Results' directory contains the results from many
     runs against different databases and platforms. To run all tests,
     execute these commands:

          shell> cd sql-bench
          shell> perl run-all-tests

     If you do not have the `sql-bench' directory, you probably
     installed MySQL using RPM files other than the source RPM. (The
     source RPM includes the `sql-bench' benchmark directory.) In this
     case, you must first install the benchmark suite before you can
     use it. There are separate benchmark RPM files named
     `mysql-bench-VERSION.i386.rpm' that contain benchmark code and
     data.

     If you have a source distribution, there are also tests in its
     `tests' subdirectory that you can run. For example, to run
     `auto_increment.tst', execute this command from the top-level
     directory of your source distribution:

          shell> mysql -vvf test < ./tests/auto_increment.tst

     The expected result of the test can be found in the
     `./tests/auto_increment.res' file.

 13. At this point, you should have the server running. However, none
     of the initial MySQL accounts have a password, and the server
     permits permissive access to test databases. To tighten security,
     follow the instructions in *Note default-privileges::.

The MySQL 5.0 installation procedure creates time zone tables in the
`mysql' database but does not populate them. To do so, use the
instructions in *Note time-zone-support::.

You can set up new accounts using the `bin/mysql_setpermission' script
if you install the `DBI' and `DBD::mysql' Perl modules. See *Note
mysql-setpermission::. For Perl module installation instructions, see
*Note perl-support::.

If you would like to use *Note `mysqlaccess': mysqlaccess. and have the
MySQL distribution in some nonstandard location, you must change the
location where *Note `mysqlaccess': mysqlaccess. expects to find the
*Note `mysql': mysql. client. Edit the `bin/mysqlaccess' script at
approximately line 18. Search for a line that looks like this:

     $MYSQL     = '/usr/local/bin/mysql';    # path to mysql executable

Change the path to reflect the location where *Note `mysql': mysql.
actually is stored on your system. If you do not do this, a `Broken
pipe' error will occur when you run *Note `mysqlaccess': mysqlaccess.


File: manual.info,  Node: mysql-install-db-problems,  Next: automatic-start,  Prev: unix-postinstallation,  Up: unix-postinstallation

3.18.1.1 Problems Running `mysql_install_db'
............................................

The purpose of the *Note `mysql_install_db': mysql-install-db. script is
to generate new MySQL privilege tables. It does not overwrite existing
MySQL privilege tables, and it does not affect any other data.

If you want to re-create your privilege tables, first stop the *Note
`mysqld': mysqld. server if it is running. Then rename the `mysql'
directory under the data directory to save it, and then run *Note
`mysql_install_db': mysql-install-db. Suppose that your current
directory is the MySQL installation directory and that *Note
`mysql_install_db': mysql-install-db. is located in the `bin' directory
and the data directory is named `data'. To rename the `mysql' database
and re-run *Note `mysql_install_db': mysql-install-db, use these
commands.

     shell> mv data/mysql data/mysql.old
     shell> bin/mysql_install_db --user=mysql

When you run *Note `mysql_install_db': mysql-install-db, you might
encounter the following problems:

   * **Note `mysql_install_db': mysql-install-db.  fails to install the
     grant tables*

     You may find that *Note `mysql_install_db': mysql-install-db. fails
     to install the grant tables and terminates after displaying the
     following messages:

          Starting mysqld daemon with databases from XXXXXX
          mysqld ended

     In this case, you should examine the error log file very
     carefully. The log should be located in the directory `XXXXXX'
     named by the error message and should indicate why *Note `mysqld':
     mysqld. did not start.  If you do not understand what happened,
     include the log when you post a bug report. See *Note
     bug-reports::.

   * *There is a *Note `mysqld': mysqld.  process running*

     This indicates that the server is running, in which case the grant
     tables have probably been created already. If so, there is no need
     to run *Note `mysql_install_db': mysql-install-db.  at all because
     it needs to be run only once (when you install MySQL the first
     time).

   * *Installing a second *Note `mysqld': mysqld. server does not work
     when one server is running*

     This can happen when you have an existing MySQL installation, but
     want to put a new installation in a different location. For
     example, you might have a production installation, but you want to
     create a second installation for testing purposes. Generally the
     problem that occurs when you try to run a second server is that it
     tries to use a network interface that is in use by the first
     server. In this case, you should see one of the following error
     messages:

          Can't start server: Bind on TCP/IP port:
          Address already in use
          Can't start server: Bind on unix socket...

     For instructions on setting up multiple servers, see *Note
     multiple-servers::.

   * *You do not have write access to the `/tmp' directory*

     If you do not have write access to create temporary files or a
     Unix socket file in the default location (the `/tmp' directory),
     an error occurs when you run *Note `mysql_install_db':
     mysql-install-db. or the *Note `mysqld': mysqld. server.

     You can specify different locations for the temporary directory
     and Unix socket file by executing these commands prior to starting
     *Note `mysql_install_db': mysql-install-db. or *Note `mysqld':
     mysqld, where SOME_TMP_DIR is the full path name to some directory
     for which you have write permission:

          shell> TMPDIR=/SOME_TMP_DIR/
          shell> MYSQL_UNIX_PORT=/SOME_TMP_DIR/mysql.sock
          shell> export TMPDIR MYSQL_UNIX_PORT

     Then you should be able to run *Note `mysql_install_db':
     mysql-install-db. and start the server with these commands:

          shell> bin/mysql_install_db --user=mysql
          shell> bin/mysqld_safe --user=mysql &

     If *Note `mysql_install_db': mysql-install-db. is located in the
     `scripts' directory, modify the first command to
     `scripts/mysql_install_db'.

     See *Note problems-with-mysql-sock::, and *Note
     environment-variables::.

There are some alternatives to running the *Note `mysql_install_db':
mysql-install-db. script provided in the MySQL distribution:

   * If you want the initial privileges to be different from the
     standard defaults, you can modify *Note `mysql_install_db':
     mysql-install-db. before you run it.  However, it is preferable to
     use *Note `GRANT': grant. and *Note `REVOKE': revoke. to change the
     privileges _after_ the grant tables have been set up. In other
     words, you can run *Note `mysql_install_db': mysql-install-db, and
     then use `mysql -u root mysql' to connect to the server as the
     MySQL `root' user so that you can issue the necessary *Note
     `GRANT': grant.  and *Note `REVOKE': revoke. statements.

     If you want to install MySQL on several machines with the same
     privileges, you can put the *Note `GRANT': grant. and *Note
     `REVOKE': revoke. statements in a file and execute the file as a
     script using `mysql' after running *Note `mysql_install_db':
     mysql-install-db. For example:

          shell> bin/mysql_install_db --user=mysql
          shell> bin/mysql -u root < your_script_file

     By doing this, you can avoid having to issue the statements
     manually on each machine.

   * It is possible to re-create the grant tables completely after they
     have previously been created. You might want to do this if you are
     just learning how to use *Note `GRANT': grant. and *Note `REVOKE':
     revoke. and have made so many modifications after running *Note
     `mysql_install_db': mysql-install-db. that you want to wipe out
     the tables and start over.

     To re-create the grant tables, remove all the `.frm', `.MYI', and
     `.MYD' files in the `mysql' database directory. Then run the *Note
     `mysql_install_db': mysql-install-db. script again.

   * You can start *Note `mysqld': mysqld. manually using the
     `--skip-grant-tables' option and add the privilege information
     yourself using *Note `mysql': mysql.:

          shell> bin/mysqld_safe --user=mysql --skip-grant-tables &
          shell> bin/mysql mysql

     From *Note `mysql': mysql, manually execute the SQL commands
     contained in *Note `mysql_install_db': mysql-install-db.  Make
     sure that you run *Note `mysqladmin flush-privileges': mysqladmin.
     or *Note `mysqladmin reload': mysqladmin. afterward to tell the
     server to reload the grant tables.

     Note that by not using *Note `mysql_install_db': mysql-install-db,
     you not only have to populate the grant tables manually, you also
     have to create them first.


File: manual.info,  Node: automatic-start,  Next: starting-server,  Prev: mysql-install-db-problems,  Up: unix-postinstallation

3.18.1.2 Starting and Stopping MySQL Automatically
..................................................

Generally, you start the *Note `mysqld': mysqld. server in one of these
ways:

   * Invoke *Note `mysqld': mysqld. directly. This works on any
     platform.

   * Run the MySQL server as a Windows service. The service can be set
     to start the server automatically when Windows starts, or as a
     manual service that you start on request.  For instructions, see
     *Note windows-start-service::.

   * Invoke *Note `mysqld_safe': mysqld-safe, which tries to determine
     the proper options for *Note `mysqld': mysqld.  and then runs it
     with those options. This script is used on Unix and Unix-like
     systems. See *Note mysqld-safe::.

   * Invoke *Note `mysql.server': mysql-server. This script is used
     primarily at system startup and shutdown on systems that use
     System V-style run directories (that is, `/etc/init.d' and
     run-level specific directories), where it usually is installed
     under the name `mysql'. The *Note `mysql.server': mysql-server.
     script starts the server by invoking *Note `mysqld_safe':
     mysqld-safe. See *Note mysql-server::.

   * On Mac OS X, install a separate MySQL Startup Item package to
     enable the automatic startup of MySQL on system startup.  The
     Startup Item starts the server by invoking *Note `mysql.server':
     mysql-server. See *Note macosx-installation::, for details.

The *Note `mysqld_safe': mysqld-safe. and *Note `mysql.server':
mysql-server. scripts and the Mac OS X Startup Item can be used to
start the server manually, or automatically at system startup time.
*Note `mysql.server': mysql-server. and the Startup Item also can be
used to stop the server.

To start or stop the server manually using the *Note `mysql.server':
mysql-server. script, invoke it with `start' or `stop' arguments:

     shell> mysql.server start
     shell> mysql.server stop

Before *Note `mysql.server': mysql-server. starts the server, it
changes location to the MySQL installation directory, and then invokes
*Note `mysqld_safe': mysqld-safe. If you want the server to run as some
specific user, add an appropriate `user' option to the `[mysqld]' group
of the `/etc/my.cnf' option file, as shown later in this section. (It
is possible that you will need to edit *Note `mysql.server':
mysql-server. if you've installed a binary distribution of MySQL in a
nonstandard location. Modify it to change location into the proper
directory before it runs *Note `mysqld_safe': mysqld-safe. If you do
this, your modified version of *Note `mysql.server': mysql-server. may
be overwritten if you upgrade MySQL in the future, so you should make a
copy of your edited version that you can reinstall.)

*Note `mysql.server stop': mysql-server. stops the server by sending a
signal to it. You can also stop the server manually by executing *Note
`mysqladmin shutdown': mysqladmin.

To start and stop MySQL automatically on your server, you need to add
start and stop commands to the appropriate places in your `/etc/rc*'
files.

If you use the Linux server RPM package (`MySQL-server-VERSION.rpm'),
the *Note `mysql.server': mysql-server. script is installed in the
`/etc/init.d' directory with the name `mysql'. You need not install it
manually.  See *Note linux-installation-rpm::, for more information on
the Linux RPM packages.

Some vendors provide RPM packages that install a startup script under a
different name such as *Note `mysqld': mysqld.

If you install MySQL from a source distribution or using a binary
distribution format that does not install *Note `mysql.server':
mysql-server. automatically, you can install it manually. The script
can be found in the `support-files' directory under the MySQL
installation directory or in a MySQL source tree.

To install *Note `mysql.server': mysql-server. manually, copy it to the
`/etc/init.d' directory with the name *Note `mysql': mysql, and then
make it executable. Do this by changing location into the appropriate
directory where *Note `mysql.server': mysql-server. is located and
executing these commands:

     shell> cp mysql.server /etc/init.d/mysql
     shell> chmod +x /etc/init.d/mysql

*Note*:

Older Red Hat systems use the `/etc/rc.d/init.d' directory rather than
`/etc/init.d'. Adjust the preceding commands accordingly.
Alternatively, first create `/etc/init.d' as a symbolic link that
points to `/etc/rc.d/init.d':

     shell> cd /etc
     shell> ln -s rc.d/init.d .

After installing the script, the commands needed to activate it to run
at system startup depend on your operating system. On Linux, you can
use `chkconfig':

     shell> chkconfig --add mysql

On some Linux systems, the following command also seems to be necessary
to fully enable the *Note `mysql': mysql. script:

     shell> chkconfig --level 345 mysql on

On FreeBSD, startup scripts generally should go in
`/usr/local/etc/rc.d/'. The `rc(8)' manual page states that scripts in
this directory are executed only if their basename matches the `*.sh'
shell file name pattern. Any other files or directories present within
the directory are silently ignored. In other words, on FreeBSD, you
should install the `mysql.server' script as
`/usr/local/etc/rc.d/mysql.server.sh' to enable automatic startup.

As an alternative to the preceding setup, some operating systems also
use `/etc/rc.local' or `/etc/init.d/boot.local' to start additional
services on startup. To start up MySQL using this method, you could
append a command like the one following to the appropriate startup file:

     /bin/sh -c 'cd /usr/local/mysql; ./bin/mysqld_safe --user=mysql &'

For other systems, consult your operating system documentation to see
how to install startup scripts.

You can add options for *Note `mysql.server': mysql-server. in a global
`/etc/my.cnf' file. A typical `/etc/my.cnf' file might look like this:

     [mysqld]
     datadir=/usr/local/mysql/var
     socket=/var/tmp/mysql.sock
     port=3306
     user=mysql

     [mysql.server]
     basedir=/usr/local/mysql

The *Note `mysql.server': mysql-server. script supports the following
options: `basedir', `datadir', and `pid-file'. If specified, they
_must_ be placed in an option file, not on the command line. *Note
`mysql.server': mysql-server.  supports only `start' and `stop' as
command-line arguments.

The following table shows which option groups the server and each
startup script read from option files.

*MySQL Startup scripts and supported server option groups*

Script         Option Groups
*Note          `[mysqld]', `[server]', `[mysqld-MAJOR_VERSION]'
`mysqld':      
mysqld.        
*Note          `[mysqld]', `[server]', `[mysqld_safe]'
`mysqld_safe': 
mysqld-safe.   
*Note          `[mysqld]', `[mysql.server]', `[server]'
`mysql.server':
mysql-server.  

`[mysqld-MAJOR_VERSION]' means that groups with names like
`[mysqld-4.1]' and `[mysqld-5.0]' are read by servers having versions
4.1.x, 5.0.x, and so forth. This feature can be used to specify options
that can be read only by servers within a given release series.

For backward compatibility, *Note `mysql.server': mysql-server. also
reads the `[mysql_server]' group and *Note `mysqld_safe': mysqld-safe.
also reads the `[safe_mysqld]' group. However, you should update your
option files to use the `[mysql.server]' and `[mysqld_safe]' groups
instead when using MySQL 5.0.

For more information on MySQL configuration files and their structure
and contents, see *Note option-files::.


File: manual.info,  Node: starting-server,  Prev: automatic-start,  Up: unix-postinstallation

3.18.1.3 Starting and Troubleshooting the MySQL Server
......................................................

This section provides troubleshooting suggestions for problems starting
the server on Unix. If you are using Windows, see *Note
windows-troubleshooting::.

If you have problems starting the server, here are some things to try:

   * Check the error log to see why the server does not start.

   * Specify any special options needed by the storage engines you are
     using.

   * Make sure that the server knows where to find the data directory.

   * Make sure that the server can access the data directory. The
     ownership and permissions of the data directory and its contents
     must be set such that the server can read and modify them.

   * Verify that the network interfaces the server wants to use are
     available.

Some storage engines have options that control their behavior.  You can
create a `my.cnf' file and specify startup options for the engines that
you plan to use. If you are going to use storage engines that support
transactional tables (`InnoDB', `BDB', *Note `NDB': mysql-cluster.), be
sure that you have them configured the way you want before starting the
server:

   * If you are using `InnoDB' tables, see *Note innodb-configuration::.

   * If you are using `BDB' (Berkeley DB) tables, see *Note bdb-start::.

   * If you are using MySQL Cluster, see *Note
     mysql-cluster-configuration::.

Storage engines will use default option values if you specify none, but
it is recommended that you review the available options and specify
explicit values for those for which the defaults are not appropriate
for your installation.

When the *Note `mysqld': mysqld. server starts, it changes location to
the data directory. This is where it expects to find databases and
where it expects to write log files. The server also writes the pid
(process ID) file in the data directory.

The data directory location is hardwired in when the server is
compiled. This is where the server looks for the data directory by
default. If the data directory is located somewhere else on your
system, the server will not work properly. You can determine what the
default path settings are by invoking *Note `mysqld': mysqld. with the
`--verbose' and `--help' options.

If the default locations do not match the MySQL installation layout on
your system, you can override them by specifying options to *Note
`mysqld': mysqld. or *Note `mysqld_safe': mysqld-safe. on the command
line or in an option file.

To specify the location of the data directory explicitly, use the
`--datadir' option. However, normally you can tell *Note `mysqld':
mysqld. the location of the base directory under which MySQL is
installed and it looks for the data directory there. You can do this
with the `--basedir' option.

To check the effect of specifying path options, invoke *Note `mysqld':
mysqld. with those options followed by the `--verbose' and `--help'
options. For example, if you change location into the directory where
*Note `mysqld': mysqld. is installed and then run the following
command, it shows the effect of starting the server with a base
directory of `/usr/local':

     shell> ./mysqld --basedir=/usr/local --verbose --help

You can specify other options such as `--datadir' as well, but
`--verbose' and `--help' must be the last options.

Once you determine the path settings you want, start the server without
`--verbose' and `--help'.

If *Note `mysqld': mysqld. is currently running, you can find out what
path settings it is using by executing this command:

     shell> mysqladmin variables

Or:

     shell> mysqladmin -h HOST_NAME variables

HOST_NAME is the name of the MySQL server host.

If you get `Errcode 13' (which means `Permission denied') when starting
*Note `mysqld': mysqld, this means that the privileges of the data
directory or its contents do not permit server access. In this case,
you change the permissions for the involved files and directories so
that the server has the right to use them. You can also start the
server as `root', but this raises security issues and should be avoided.

On Unix, change location into the data directory and check the
ownership of the data directory and its contents to make sure the
server has access. For example, if the data directory is
`/usr/local/mysql/var', use this command:

     shell> ls -la /usr/local/mysql/var

If the data directory or its files or subdirectories are not owned by
the login account that you use for running the server, change their
ownership to that account. If the account is named `mysql', use these
commands:

     shell> chown -R mysql /usr/local/mysql/var
     shell> chgrp -R mysql /usr/local/mysql/var

If it possible that even with correct ownership, MySQL may fail to
start up if there is other security software running on your system
that manages application access to various parts of the file system. In
this case, you may need to reconfigure that software to enable *Note
`mysqld': mysqld. to access the directories it uses during normal
operation.

If the server fails to start up correctly, check the error log.  Log
files are located in the data directory (typically `C:\Program
Files\MySQL\MySQL Server 5.0\data' on Windows, `/usr/local/mysql/data'
for a Unix binary distribution, and `/usr/local/var' for a Unix source
distribution). Look in the data directory for files with names of the
form `HOST_NAME.err' and `HOST_NAME.log', where HOST_NAME is the name
of your server host. Then examine the last few lines of these files. On
Unix, you can use `tail' to display them:

     shell> tail HOST_NAME.err
     shell> tail HOST_NAME.log

The error log should contain information that indicates why the server
could not start. For example, you might see something like this in the
log:

     000729 14:50:10  bdb:  Recovery function for LSN 1 27595 failed
     000729 14:50:10  bdb:  warning: ./test/t1.db: No such file or directory
     000729 14:50:10  Can't init databases

This means that you did not start *Note `mysqld': mysqld. with the
`--bdb-no-recover' option and Berkeley DB found something wrong with
its own log files when it tried to recover your databases. To be able
to continue, you should move the old Berkeley DB log files from the
database directory to some other place, where you can later examine
them.  The `BDB' log files are named in sequence beginning with
`log.0000000001', where the number increases over time.

If you are running *Note `mysqld': mysqld. with `BDB' table support and
*Note `mysqld': mysqld. dumps core at startup, this could be due to
problems with the `BDB' recovery log. In this case, you can try
starting *Note `mysqld': mysqld. with `--bdb-no-recover'. If that helps,
you should remove all `BDB' log files from the data directory and try
starting *Note `mysqld': mysqld. again without the `--bdb-no-recover'
option.

If either of the following errors occur, it means that some other
program (perhaps another *Note `mysqld': mysqld. server) is using the
TCP/IP port or Unix socket file that *Note `mysqld': mysqld. is trying
to use:

     Can't start server: Bind on TCP/IP port: Address already in use
     Can't start server: Bind on unix socket...

Use `ps' to determine whether you have another *Note `mysqld': mysqld.
server running. If so, shut down the server before starting *Note
`mysqld': mysqld. again. (If another server is running, and you really
want to run multiple servers, you can find information about how to do
so in *Note multiple-servers::.)

If no other server is running, try to execute the command `telnet
YOUR_HOST_NAME TCP_IP_PORT_NUMBER'. (The default MySQL port number is
3306.) Then press Enter a couple of times. If you do not get an error
message like `telnet: Unable to connect to remote host: Connection
refused', some other program is using the TCP/IP port that *Note
`mysqld': mysqld. is trying to use. You will need to track down what
program this is and disable it, or else tell *Note `mysqld': mysqld. to
listen to a different port with the `--port' option. In this case, you
will also need to specify the port number for client programs when
connecting to the server using TCP/IP.

Another reason the port might be inaccessible is that you have a
firewall running that blocks connections to it. If so, modify the
firewall settings to permit access to the port.

If the server starts but you cannot connect to it, you should make sure
that you have an entry in `/etc/hosts' that looks like this:

     127.0.0.1       localhost

If you cannot get *Note `mysqld': mysqld. to start, you can try to make
a trace file to find the problem by using the `--debug' option. See
MySQL Internals: Porting
(http://forge.mysql.com/wiki/MySQL_Internals_Porting).


File: manual.info,  Node: default-privileges,  Prev: unix-postinstallation,  Up: postinstallation

3.18.2 Securing the Initial MySQL Accounts
------------------------------------------

Part of the MySQL installation process is to set up the `mysql'
database that contains the grant tables:

   * Windows distributions contain preinitialized grant tables.

   * On Unix, the *Note `mysql_install_db': mysql-install-db. program
     populates the grant tables. Some installation methods run this
     program for you. Others require that you execute it manually.  For
     details, see *Note unix-postinstallation::.

The `mysql.user' grant table defines the initial MySQL user accounts
and their access privileges:

   * Some accounts have the user name `root'.  These are superuser
     accounts that have all privileges and can do anything. The initial
     `root' account passwords are empty, so anyone can connect to the
     MySQL server as `root' _without a password_ and be granted all
     privileges.

        * On Windows, `root' accounts are created that permit
          connections from the local host only.  Connections can be
          made by specifying the host name `localhost' or the IP address
          `127.0.0.1'. If the user selects the `Enable root access from
          remote machines' option during installation, the Windows
          installer creates another `root' account that permits
          connections from any host.

        * On Unix, each `root' account permits connections from the
          local host. Connections can be made by specifying the host
          name `localhost', the IP address `127.0.0.1', or the actual
          host name or IP address.

     An attempt to connect to the host `127.0.0.1' normally resolves to
     the `localhost' account.  However, this fails if the server is run
     with the `--skip-name-resolve' option, so the `127.0.0.1' account
     is useful in that case.

   * Some accounts are for anonymous users. These have an empty user
     name. The anonymous accounts have no password, so anyone can use
     them to connect to the MySQL server.

        * On Windows, there is one anonymous account that permits
          connections from the local host. Connections can be made by
          specifying a host name of `localhost'.  It has no global
          privileges. (Before MySQL 5.0.36, it has all global
          privileges, just like the `root' accounts.)

        * On Unix, each anonymous account permits connections from the
          local host. Connections can be made by specifying a host name
          of `localhost' for one of the accounts, or the actual host
          name or IP address for the other.

To display which accounts exist in the `mysql.user' table and check
whether their passwords are empty, use the following statement:

     mysql> SELECT User, Host, Password FROM mysql.user;
     +------+--------------------+----------+
     | User | Host               | Password |
     +------+--------------------+----------+
     | root | localhost          |          |
     | root | myhost.example.com |          |
     | root | 127.0.0.1          |          |
     |      | localhost          |          |
     |      | myhost.example.com |          |
     +------+--------------------+----------+

This output indicates that there are several `root' and anonymous-user
accounts, none of which have passwords. The output might differ on your
system, but the presence of accounts with empty passwords means that
your MySQL installation is unprotected until you do something about it:

   * You should assign a password to each MySQL `root' account.

   * If you want to prevent clients from connecting as anonymous users
     without a password, you should either assign a password to each
     anonymous account or else remove the accounts.

In addition, the `mysql.db' table contains rows that permit all
accounts to access the `test' database and other databases with names
that start with `test_'. This is true even for accounts that otherwise
have no special privileges such as the default anonymous accounts. This
is convenient for testing but inadvisable on production servers.
Administrators who want database access restricted only to accounts
that have permissions granted explicitly for that purpose should remove
these `mysql.db' table rows.

The following instructions describe how to set up passwords for the
initial MySQL accounts, first for the `root' accounts, then for the
anonymous accounts. The instructions also cover how to remove the
anonymous accounts, should you prefer not to permit anonymous access at
all, and describe how to remove permissive access to test databases.
Replace NEWPWD in the examples with the password that you want to use.
Replace HOST_NAME with the name of the server host. You can determine
this name from the output of the preceding *Note `SELECT': select.
statement. For the output shown, HOST_NAME is `myhost.example.com'.

*Note*:

For additional information about setting passwords, see *Note
assigning-passwords::. If you forget your `root' password after setting
it, see *Note resetting-permissions::.

You might want to defer setting the passwords until later, to avoid the
need to specify them while you perform additional setup or testing.
However, be sure to set them before using your installation for
production purposes.

To set up additional accounts, see *Note adding-users::.

* Assigning `root' Account Passwords *

The `root' account passwords can be set several ways. The following
discussion demonstrates three methods:

   * Use the *Note `SET PASSWORD': set-password. statement

   * Use the *Note `UPDATE': update. statement

   * Use the *Note `mysqladmin': mysqladmin. command-line client program

To assign passwords using *Note `SET PASSWORD': set-password, connect
to the server as `root' and issue a *Note `SET PASSWORD': set-password.
statement for each `root' account listed in the `mysql.user' table. Be
sure to encrypt the password using the `PASSWORD()' function.

For Windows, do this:

     shell> mysql -u root
     mysql> SET PASSWORD FOR 'root'@'localhost' = PASSWORD('NEWPWD');
     mysql> SET PASSWORD FOR 'root'@'127.0.0.1' = PASSWORD('NEWPWD');
     mysql> SET PASSWORD FOR 'root'@'%' = PASSWORD('NEWPWD');

The last statement is unnecessary if the `mysql.user' table has no
`root' account with a host value of `%'.

For Unix, do this:

     shell> mysql -u root
     mysql> SET PASSWORD FOR 'root'@'localhost' = PASSWORD('NEWPWD');
     mysql> SET PASSWORD FOR 'root'@'127.0.0.1' = PASSWORD('NEWPWD');
     mysql> SET PASSWORD FOR 'root'@'HOST_NAME' = PASSWORD('NEWPWD');

You can also use a single statement that assigns a password to all
`root' accounts by using *Note `UPDATE': update. to modify the
`mysql.user' table directly. This method works on any platform:

     shell> mysql -u root
     mysql> UPDATE mysql.user SET Password = PASSWORD('NEWPWD')
         ->     WHERE User = 'root';
     mysql> FLUSH PRIVILEGES;

The *Note `FLUSH': flush. statement causes the server to reread the
grant tables. Without it, the password change remains unnoticed by the
server until you restart it.

To assign passwords to the `root' accounts using *Note `mysqladmin':
mysqladmin, execute the following commands:

     shell> mysqladmin -u root password "NEWPWD"
     shell> mysqladmin -u root -h HOST_NAME password "NEWPWD"

Those commands apply both to Windows and to Unix. The double quotation
marks around the password are not always necessary, but you should use
them if the password contains spaces or other characters that are
special to your command interpreter.

The *Note `mysqladmin': mysqladmin. method of setting the `root'
account passwords does not work for the `'root'@'127.0.0.1'' account.
Use the *Note `SET PASSWORD': set-password. method shown earlier.

After the `root' passwords have been set, you must supply the
appropriate password whenever you connect as `root' to the server. For
example, to shut down the server with *Note `mysqladmin': mysqladmin,
use this command:

     shell> mysqladmin -u root -p shutdown
     Enter password: (ENTER ROOT PASSWORD HERE)

* Assigning Anonymous Account Passwords *

The *Note `mysql': mysql. commands in the following instructions
include a `-p' option based on the assumption that you have set the
`root' account passwords using the preceding instructions and must
specify that password when connecting to the server.

To assign passwords to the anonymous accounts, connect to the server as
`root', then use either *Note `SET PASSWORD': set-password. or *Note
`UPDATE': update. Be sure to encrypt the password using the `PASSWORD()'
function.

To use *Note `SET PASSWORD': set-password. on Windows, do this:

     shell> mysql -u root -p
     Enter password: (ENTER ROOT PASSWORD HERE)
     mysql> SET PASSWORD FOR ''@'localhost' = PASSWORD('NEWPWD');

To use *Note `SET PASSWORD': set-password. on Unix, do this:

     shell> mysql -u root -p
     Enter password: (ENTER ROOT PASSWORD HERE)
     mysql> SET PASSWORD FOR ''@'localhost' = PASSWORD('NEWPWD');
     mysql> SET PASSWORD FOR ''@'HOST_NAME' = PASSWORD('NEWPWD');

To set the anonymous-user account passwords with a single *Note
`UPDATE': update. statement, do this (on any platform):

     shell> mysql -u root -p
     Enter password: (ENTER ROOT PASSWORD HERE)
     mysql> UPDATE mysql.user SET Password = PASSWORD('NEWPWD')
         ->     WHERE User = '';
     mysql> FLUSH PRIVILEGES;

The *Note `FLUSH': flush. statement causes the server to reread the
grant tables. Without it, the password change remains unnoticed by the
server until you restart it.

* Removing Anonymous Accounts *

If you prefer to remove any anonymous accounts rather than assigning
them passwords, do so as follows on Windows:

     shell> mysql -u root -p
     Enter password: (ENTER ROOT PASSWORD HERE)
     mysql> DROP USER ''@'localhost';

On Unix, remove the anonymous accounts like this:

     shell> mysql -u root -p
     Enter password: (ENTER ROOT PASSWORD HERE)
     mysql> DROP USER ''@'localhost';
     mysql> DROP USER ''@'HOST_NAME';

* Securing Test Databases *

By default, the `mysql.db' table contains rows that permit access by
any user to the `test' database and other databases with names that
start with `test_'. (These rows have an empty `User' column value,
which for access-checking purposes matches any user name.) This means
that such databases can be used even by accounts that otherwise possess
no privileges.  If you want to remove any-user access to test
databases, do so as follows:

     shell> mysql -u root -p
     Enter password: (ENTER ROOT PASSWORD HERE)
     mysql> DELETE FROM mysql.db WHERE Db LIKE 'test%';
     mysql> FLUSH PRIVILEGES;

The *Note `FLUSH': flush. statement causes the server to reread the
grant tables. Without it, the privilege change remains unnoticed by the
server until you restart it.

With the preceding change, only users who have global database
privileges or privileges granted explicitly for the `test' database can
use it. However, if you do not want the database to exist at all, drop
it:

     mysql> DROP DATABASE test;

*Note*:

On Windows, you can also perform the process described in this section
using the Configuration Wizard (see *Note
mysql-config-wizard-security::). On other platforms, the MySQL
distribution includes *Note `mysql_secure_installation':
mysql-secure-installation, a command-line utility that automates much
of the process of securing a MySQL installation.


File: manual.info,  Node: upgrading-downgrading,  Next: operating-system-specific-notes,  Prev: postinstallation,  Up: installing

3.19 Upgrading or Downgrading MySQL
===================================

* Menu:

* upgrading::                    Upgrading MySQL
* downgrading::                  Downgrading MySQL
* checking-table-incompatibilities::  Checking Whether Tables or Indexes Must Be Rebuilt
* rebuilding-tables::            Rebuilding or Repairing Tables or Indexes
* copying-databases::            Copying MySQL Databases to Another Machine


File: manual.info,  Node: upgrading,  Next: downgrading,  Prev: upgrading-downgrading,  Up: upgrading-downgrading

3.19.1 Upgrading MySQL
----------------------

* Menu:

* upgrading-from-early-5-0::     Upgrading from MySQL 5.0 to 5.0.10 or Higher
* upgrading-from-previous-series::  Upgrading from MySQL 4.1 to 5.0

As a general rule, to upgrade from one release series to another, you
should go to the next series rather than skipping a series. To upgrade
from a release series previous to MySQL 4.1, upgrade to each successive
release series in turn until you have reached MySQL 4.1, and then
proceed with the upgrade to MySQL 5.0. For example, if you currently are
running MySQL 4.0 and wish to upgrade to a newer series, upgrade to
MySQL 4.1 first before upgrading to 5.0, and so forth. For information
on upgrading to MySQL 4.1 or earlier releases, see the `MySQL 3.23,
4.0, 4.1 Reference Manual'.

To upgrade from MySQL 4.1 to 5.0, use the items in the following
checklist as a guide:

   * Before any upgrade, back up your databases, including the `mysql'
     database that contains the grant tables. See *Note
     backup-methods::.

   * Read _all_ the notes in *Note upgrading-from-previous-series::.
     These notes enable you to identify upgrade issues that apply to
     your current MySQL installation. Some incompatibilities discussed
     in that section require your attention _before_ upgrading. Others
     should be dealt with _after_ upgrading.

   * Read *Note news:: as well, which provides information about
     features that are new in MySQL 5.0 or differ from those found in
     MySQL 4.1.

   * After upgrading to a new version of MySQL, run *Note
     `mysql_upgrade': mysql-upgrade. (see *Note mysql-upgrade::). This
     program checks your tables, and attempts to repair them if
     necessary. It also updates your grant tables to make sure that
     they have the current structure so that you can take advantage of
     any new capabilities. (Some releases of MySQL introduce changes to
     the structure of the grant tables to add new privileges or
     features.)

     *Note `mysql_upgrade': mysql-upgrade. does not upgrade the contents
     of the help tables. For upgrade instructions, see *Note
     server-side-help-support::.

   * If you run MySQL Server on Windows, see *Note windows-upgrading::.

   * If you use replication, see *Note replication-upgrade::, for
     information on upgrading your replication setup.

   * If you upgrade an installation originally produced by installing
     multiple RPM packages, it is best to upgrade all the packages, not
     just some. For example, if you previously installed the server and
     client RPMs, do not upgrade just the server RPM.

   * MySQL 5.0.27 is the last version in MySQL 5.0 for which MySQL-Max
     binary distributions are provided, except for RPM distributions.
     For RPMs, MySQL 5.0.37 is the last release.  After these versions,
     the features previously included in the `mysqld-max' server are
     included in *Note `mysqld': mysqld.

     If you previously installed a MySQL-Max distribution that includes
     a server named `mysqld-max', and then upgrade later to a non-Max
     version of MySQL, *Note `mysqld_safe': mysqld-safe. still attempts
     to run the old `mysqld-max' server. If you perform such an
     upgrade, you should remove the old `mysqld-max' server manually to
     ensure that *Note `mysqld_safe': mysqld-safe. runs the new *Note
     `mysqld': mysqld. server.

You can always move the MySQL format files and data files between
different versions on systems with the same architecture as long as you
stay within versions for the same release series of MySQL.

If you are cautious about using new versions, you can always rename
your old *Note `mysqld': mysqld. before installing a newer one. For
example, if you are using a version of MySQL 4.1 and want to upgrade to
5.0, rename your current server from *Note `mysqld': mysqld. to
`mysqld-4.1'. If your new *Note `mysqld': mysqld. then does something
unexpected, you can simply shut it down and restart with your old *Note
`mysqld': mysqld.

If, after an upgrade, you experience problems with compiled client
programs, such as `Commands out of sync' or unexpected core dumps, you
probably have used old header or library files when compiling your
programs. In this case, you should check the date for your `mysql.h'
file and `libmysqlclient.a' library to verify that they are from the
new MySQL distribution. If not, recompile your programs with the new
headers and libraries. Recompilation might also be necessary for
programs compiled against the shared client library if the library
major version number has changed (for example from
`libmysqlclient.so.15' to `libmysqlclient.so.16'.

If problems occur, such as that the new *Note `mysqld': mysqld.  server
does not start or that you cannot connect without a password, verify
that you do not have an old `my.cnf' file from your previous
installation.  You can check this with the `--print-defaults' option
(for example, *Note `mysqld --print-defaults': mysqld.). If this
command displays anything other than the program name, you have an
active `my.cnf' file that affects server or client operation.

If your MySQL installation contains a large amount of data that might
take a long time to convert after an in-place upgrade, you might find
it useful to create a `dummy' database instance for assessing what
conversions might be needed and the work involved to perform them. Make
a copy of your MySQL instance that contains a full copy of the `mysql'
database, plus all other databases without data. Run your upgrade
procedure on this dummy instance to see what actions might be needed so
that you can better evaluate the work involved when performing actual
data conversion on your original database instance.

It is a good idea to rebuild and reinstall the Perl `DBD::mysql' module
whenever you install a new release of MySQL. The same applies to other
MySQL interfaces as well, such as PHP `mysql' extensions and the Python
`MySQLdb' module.


File: manual.info,  Node: upgrading-from-early-5-0,  Next: upgrading-from-previous-series,  Prev: upgrading,  Up: upgrading

3.19.1.1 Upgrading from MySQL 5.0 to 5.0.10 or Higher
.....................................................

*After upgrading a 5.0 installation to 5.0.10 or higher*, it is
_necessary_ to upgrade your grant tables.  Otherwise, creating stored
procedures and functions might not work. The procedure for doing this
is described in *Note mysql-upgrade::.


File: manual.info,  Node: upgrading-from-previous-series,  Prev: upgrading-from-early-5-0,  Up: upgrading

3.19.1.2 Upgrading from MySQL 4.1 to 5.0
........................................

*Note*:

It is good practice to back up your data before installing any new
version of software. Although MySQL works very hard to ensure a high
level of quality, you should protect your data by making a backup.

To upgrade to 5.0 from any previous version, MySQL recommends that you
dump your tables with *Note `mysqldump': mysqldump. before upgrading
and reload the dump file after upgrading.

In general, you should do the following when upgrading from MySQL 4.1
to 5.0:

   * Read _all_ the items in the following sections to see whether any
     of them might affect your applications:

        * *Note upgrading::, has general update information.

        * The items in the change lists found later in this section
          enable you to identify upgrade issues that apply to your
          current MySQL installation.

        * The MySQL 5.0 change history describes significant new
          features you can use in 5.0 or that differ from those found
          in MySQL 4.1. Some of these changes may result in
          incompatibilities. See *Note news-5-0-x::.

     Note particularly any changes that are marked *Known issue* or
     *Incompatible change*. These incompatibilities with earlier
     versions of MySQL may require your attention _before you upgrade_.
     Our aim is to avoid these changes, but occasionally they are
     necessary to correct problems that would be worse than an
     incompatibility between releases. If any upgrade issue applicable
     to your installation involves an incompatibility that requires
     special handling, follow the instructions given in the
     incompatibility description. Often this will involve dumping and
     reloading tables, or use of a statement such as *Note `CHECK
     TABLE': check-table. or *Note `REPAIR TABLE': repair-table.

     For dump and reload instructions, see *Note rebuilding-tables::.
     Any procedure that involves *Note `REPAIR TABLE': repair-table.
     with the `USE_FRM' option _must_ be done before upgrading. Use of
     this statement with a version of MySQL different from the one used
     to create the table (that is, using it after upgrading) may damage
     the table. See *Note repair-table::.

   * Before upgrading to a new version of MySQL, *Note
     checking-table-incompatibilities::, to see whether changes to
     table formats or to character sets or collations were made between
     your current version of MySQL and the version to which you are
     upgrading. If so and these changes result in an incompatibility
     between MySQL versions, you will need to upgrade the affected
     tables using the instructions in *Note rebuilding-tables::.

   * After upgrading to a new version of MySQL, run *Note
     `mysql_upgrade': mysql-upgrade. (see *Note mysql-upgrade::). This
     program checks your tables, and attempts to repair them if
     necessary. It also updates your grant tables to make sure that
     they have the current structure so that you can take advantage of
     any new capabilities. (Some releases of MySQL introduce changes to
     the structure of the grant tables to add new privileges or
     features.)

     *Note `mysql_upgrade': mysql-upgrade. does not upgrade the
     contents of the help tables. For upgrade instructions, see *Note
     server-side-help-support::.

   * If you run MySQL Server on Windows, see *Note windows-upgrading::.

   * MySQL 5.0 adds support for stored procedures.  This support
     requires the `mysql.proc' table. To create this table, you should
     run the *Note `mysql_upgrade': mysql-upgrade. program as described
     in *Note mysql-upgrade::.

   * MySQL 5.0 adds support for views. This support requires extra
     privilege columns in the `mysql.user' and `mysql.db' tables. To
     create these columns, you should run the *Note `mysql_upgrade':
     mysql-upgrade. program as described in *Note mysql-upgrade::.

   * If you use replication, see *Note replication-upgrade::, for
     information on upgrading your replication setup.

If your MySQL installation contains a large amount of data that might
take a long time to convert after an in-place upgrade, you might find
it useful to create a `dummy' database instance for assessing what
conversions might be needed and the work involved to perform them. Make
a copy of your MySQL instance that contains a full copy of the `mysql'
database, plus all other databases without data. Run your upgrade
procedure on this dummy instance to see what actions might be needed so
that you can better evaluate the work involved when performing actual
data conversion on your original database instance.

Several visible behaviors have changed between MySQL 4.1 and MySQL 5.0
to make MySQL more compatible with standard SQL. These changes may
affect your applications.

The following lists describe changes that may affect applications and
that you should watch out for when upgrading from MySQL 4.1 to 5.0.

* Server Changes *

   * *Incompatible change*: *Note `SHOW CREATE VIEW': show-create-view.
     displays view definitions using an `AS ALIAS_NAME' clause for each
     column. If a column is created from an expression, the default
     alias is the expression text, which can be quite long. As of MySQL
     5.0.52, aliases for column names in *Note `CREATE VIEW':
     create-view. statements are checked against the maximum column
     length of 64 characters (not the maximum alias length of 256
     characters). As a result, views created from the output of *Note
     `SHOW CREATE VIEW': show-create-view. fail if any column alias
     exceeds 64 characters. This can cause problems for replication or
     loading dump files. For additional information and workarounds, see
     *Note view-restrictions::.

   * *Incompatible change*: Character set changes were made in MySQL
     5.0.48 that may require table indexes to be rebuilt. For details,
     see *Note checking-table-incompatibilities::.

   * *Incompatible change*: Beginning with MySQL 5.0.42, when a *Note
     `DATE': datetime. value is compared with a *Note `DATETIME':
     datetime. value, the *Note `DATE': datetime. value is coerced to
     the *Note `DATETIME': datetime. type by adding the time portion as
     `00:00:00'. Previously, the time portion of the *Note `DATETIME':
     datetime.  value was ignored, or the comparison could be performed
     as a string comparison. To mimic the old behavior, use the
     `CAST()' function to cause the comparison operands to be treated
     as previously. For example:

          DATE_COL = CAST(NOW() AS DATE)

   * *Incompatible change*: For *Note `ENUM': enum. columns that had
     enumeration values containing commas, the commas were mapped to
     `0xff' internally. However, this rendered the commas
     indistinguishable from true `0xff' characters in the values. This
     no longer occurs. However, the fix requires that you dump and
     reload any tables that have *Note `ENUM': enum. columns containing
     true `0xff' in their values: Dump the tables using *Note
     `mysqldump': mysqldump. with the current server before upgrading
     from a version of MySQL 5.0 older than 5.0.36 to version 5.0.36 or
     newer.

   * *Incompatible change*. For *Note `BINARY': binary-varbinary.
     columns, the pad value and how it is handled has changed as of
     MySQL 5.0.15. The pad value for inserts now is `0x00' rather than
     space, and there is no stripping of the pad value for retrievals.
     For details, see *Note binary-varbinary::.

   * *Incompatible change*: As of MySQL 5.0.13, `InnoDB' rolls back
     only the last statement on a transaction timeout. As of MySQL
     5.0.32, a new option, `--innodb_rollback_on_timeout', causes
     `InnoDB' to abort and roll back the entire transaction if a
     transaction timeout occurs (the same behavior as in MySQL 4.1).

   * *Incompatible change*: The namespace for triggers changed in MySQL
     5.0.10. Previously, trigger names had to be unique per table. Now
     they must be unique within the schema (database). An implication
     of this change is that *Note `DROP TRIGGER': drop-trigger.  syntax
     now uses a schema name instead of a table name (schema name is
     optional and, if omitted, the current schema will be used).

     When upgrading from a version of MySQL 5 older than 5.0.10 to
     MySQL 5.0.10 or newer, you must drop all triggers and re-create
     them or *Note `DROP TRIGGER': drop-trigger. will not work after
     the upgrade. Here is a suggested procedure for doing this:

       1. Upgrade to MySQL 5.0.10 or later to be able to access trigger
          information in the *Note `INFORMATION_SCHEMA.TRIGGERS':
          triggers-table.  table. (This should work even for pre-5.0.10
          triggers.)

       2. Dump all trigger definitions using the following *Note
          `SELECT': select. statement:

               SELECT CONCAT('CREATE TRIGGER ', t.TRIGGER_SCHEMA, '.', t.TRIGGER_NAME,
                             ' ', t.ACTION_TIMING, ' ', t.EVENT_MANIPULATION, ' ON ',
                             t.EVENT_OBJECT_SCHEMA, '.', t.EVENT_OBJECT_TABLE,
                             ' FOR EACH ROW ', t.ACTION_STATEMENT, '//' )
               INTO OUTFILE '/tmp/triggers.sql'
               FROM INFORMATION_SCHEMA.TRIGGERS AS t;

          The statement uses `INTO OUTFILE', so you must have the `FILE'
          privilege. The file will be created on the server host.  Use
          a different file name if you like. To be 100% safe, inspect
          the trigger definitions in the `triggers.sql' file, and
          perhaps make a backup of the file.

       3. Stop the server and drop all triggers by removing all `.TRG'
          files in your database directories. Change location to your
          data directory and issue this command:

               shell> rm */*.TRG

       4. Start the server and re-create all triggers using the
          `triggers.sql' file:

               mysql> delimiter // ;
               mysql> source /tmp/triggers.sql //

       5. Use the `SHOW TRIGGERS' statement to check that all triggers
          were created successfully.

   * *Incompatible change*: The indexing order for end-space in *Note
     `TEXT': blob. columns for `InnoDB' and `MyISAM' tables has
     changed. Starting from 5.0.3, *Note `TEXT': blob. indexes are
     compared as space-padded at the end (just as MySQL sorts *Note
     `CHAR': char, *Note `VARCHAR': char. and *Note `TEXT': blob.
     fields). If you have an index on a *Note `TEXT': blob. column, you
     should run *Note `CHECK TABLE': check-table. on it.  If the check
     reports errors, rebuild the indexes: Dump and reload the table if
     it is an `InnoDB' table, or run *Note `OPTIMIZE TABLE':
     optimize-table.  or *Note `REPAIR TABLE': repair-table. if it is a
     `MyISAM' table.

   * *Incompatible change*. As of MySQL 5.0.3, trailing spaces no
     longer are removed from values stored in *Note `VARCHAR': char. and
     *Note `VARBINARY': binary-varbinary. columns. The maximum lengths
     for *Note `VARCHAR': char.  and *Note `VARBINARY':
     binary-varbinary. columns in MySQL 5.0.3 and later are 65,535
     characters and 65,535 bytes, respectively.

     When a binary upgrade (file system-level copy of data files) to
     MySQL 5.0 is performed for a table with a *Note `VARBINARY':
     binary-varbinary. column, the column is space-padded to the full
     permissible width of the column.  This causes values in *Note
     `VARBINARY': binary-varbinary. columns that do not occupy the full
     width of the column to include extra trailing spaces after the
     upgrade, which means that the data in the column is different.

     In addition, new rows inserted into a table upgraded in this way
     will be space padded to the full width of the column.

     This issue can be resolved as follows:

       1. For each table containing *Note `VARBINARY':
          binary-varbinary. columns, execute the following statement,
          where TBL_NAME is the name of the table and ENGINE_NAME is the
          name of the storage engine currently used by TBL_NAME:

               ALTER TABLE TBL_NAME ENGINE=ENGINE_NAME;

          In other words, if the table named `mytable' uses the
          `MyISAM' storage engine, then you would use this statement:

               ALTER TABLE mytable ENGINE=MYISAM;

          This rebuilds the table so that it uses the 5.0 *Note
          `VARBINARY': binary-varbinary. format.

       2. Then you must remove all trailing spaces from any *Note
          `VARBINARY': binary-varbinary. column values.  For each *Note
          `VARBINARY': binary-varbinary. column VARBINARY_COLUMN,
          execute the following statement, where TBL_NAME is the name
          of the table containing the *Note `VARBINARY':
          binary-varbinary. column:

               UPDATE TBL_NAME SET VARBINARY_COLUMN = RTRIM(VARBINARY_COLUMN);

          This is necessary and safe because trailing spaces are
          stripped before 5.0.3, meaning that any trailing spaces are
          erroneous.

     This problem does not occur (and thus these two steps are not
     required) for tables upgraded using the recommended procedure of
     dumping tables prior to the upgrade and reloading them afterward.

     *Note*:

     If you create a table with new *Note `VARCHAR': char. or *Note
     `VARBINARY': binary-varbinary. columns in MySQL 5.0.3 or later,
     the table will not be usable if you downgrade to a version older
     than 5.0.3. Dump the table with *Note `mysqldump': mysqldump.
     before downgrading and reload it after downgrading.

   * *Incompatible change*: The implementation of *Note `DECIMAL':
     numeric-types. was changed in MySQL 5.0.3. You should make your
     applications aware of this change. For information about this
     change, and about possible incompatibilities with old
     applications, see *Note precision-math::, in particular, *Note
     precision-math-decimal-changes::.

     *Note `DECIMAL': numeric-types. columns are stored in a more
     efficient format. To convert a table to use the new *Note
     `DECIMAL': numeric-types. type, you should do an *Note `ALTER
     TABLE': alter-table. on it. (The *Note `ALTER TABLE': alter-table.
     also will change the table's *Note `VARCHAR': char. columns to use
     the new *Note `VARCHAR': char. data type properties, described in
     a separate item.)

     A consequence of the change in handling of the *Note `DECIMAL':
     numeric-types. and *Note `NUMERIC': numeric-types. fixed-point data
     types is that the server is more strict to follow standard SQL.
     For example, a data type of `DECIMAL(3,1)' stores a maximum value
     of 99.9. Before MySQL 5.0.3, the server permitted larger numbers
     to be stored. That is, it stored a value such as 100.0 as 100.0.
     As of MySQL 5.0.3, the server clips 100.0 to the maximum
     permissible value of 99.9. If you have tables that were created
     before MySQL 5.0.3 and that contain floating-point data not
     strictly legal for the data type, you should alter the data types
     of those columns. For example:

          ALTER TABLE TBL_NAME MODIFY COL_NAME DECIMAL(4,1);

     The behavior used by the server for *Note `DECIMAL':
     numeric-types. columns in a table depends on the version of MySQL
     used to create the table. If your server is from MySQL 5.0.3 or
     higher, but you have *Note `DECIMAL': numeric-types. columns in
     tables that were created before 5.0.3, the old behavior still
     applies to those columns. To convert the tables to the newer *Note
     `DECIMAL': numeric-types. format, dump them with *Note
     `mysqldump': mysqldump. and reload them.

   * *Incompatible change*: MySQL 5.0.3 and up uses precision math when
     calculating with *Note `DECIMAL': numeric-types. and integer
     columns (64 decimal digits) and for rounding exact-value numbers.
     Rounding behavior is well-defined, not dependent on the
     implementation of the underlying C library. However, this might
     result in incompatibilities for applications that rely on the old
     behavior. (For example, inserting .5 into an *Note `INT':
     numeric-types. column results in 1 as of MySQL 5.0.3, but might be
     0 in older versions.) For more information about rounding
     behavior, see *Note precision-math-rounding::, and *Note
     precision-math-examples::.

   * *Incompatible change*: In very old versions of MySQL (prior to
     4.1), the *Note `TIMESTAMP': datetime. data type supported a
     display width, which was silenty ignored beginning with MySQL 4.1.
     This is deprecated in MySQL 5.1, and removed altogether in MySQL
     5.5. These changes in behavior can lead to two problem scenarios
     when trying to use *Note `TIMESTAMP(N)': datetime.  columns with a
     MySQL 5.5 or later server:

        * When importing a dump file (for example, one created using
          *Note `mysqldump': mysqldump.) created in a MySQL 5.0 or
          earlier server into a server from a newer release series, a
          *Note `CREATE TABLE': create-table. or *Note `ALTER TABLE':
          alter-table. statement containing *Note `TIMESTAMP(N)':
          datetime.  causes the import to fail with a syntax error.

          To fix this problem, edit the dump file in a text editor to
          replace any instances of *Note `TIMESTAMP(N)': datetime.
          with *Note `TIMESTAMP': datetime. prior to importing the
          file. Be sure to use a plain text editor for this, and not a
          word processor; otherwise, the result is almost certain to be
          unusable for importing into the MySQL server.

        * When trying replicate any *Note `CREATE TABLE': create-table.
          or *Note `ALTER TABLE': alter-table. statement containing
          *Note `TIMESTAMP(N)': datetime.  from a master MySQL server
          that supports the *Note `TIMESTAMP(N)': datetime.  syntax to
          a MySQL 5.5 or newer slave, the statement causes replication
          to fail. Similarly, when you try to restore from a binary log
          written by a server that supports *Note `TIMESTAMP(N)':
          datetime.  to a MySQL 5.5 or newer server, any *Note `CREATE
          TABLE': create-table. or *Note `ALTER TABLE': alter-table.
          statement containing *Note `TIMESTAMP(N)': datetime.  causes
          the backup to fail. This holds true regardless of the logging
          format used by a MySQL 5.1 or newer server.

          It may be possible to fix such issues using a hex editor, by
          replacing any width arguments used with *Note `TIMESTAMP':
          datetime, and the parentheses containing them, with space
          characters (hexadecimal `20'). This can be made to work as
          long as checksums were not enabled when creating the binary
          log. Be sure to use a programmer's binary hex editor and not
          a regular text editor or word processor for this; otherwise,
          the result is almost certain to be a corrupted binary log
          file. To guard against accidental corruption of the binary
          log, you should always work on a copy of the file rather than
          the original.

     You should try to handle potential issues of these types
     proactively by updating with *Note `ALTER TABLE': alter-table. any
     *Note `TIMESTAMP(N)': datetime. columns in your databases so that
     they use *Note `TIMESTAMP': datetime. instead, before performing
     any upgrades.

   * *Incompatible change*: `MyISAM' and `InnoDB' tables created with
     *Note `DECIMAL': numeric-types.  columns in MySQL 5.0.3 to 5.0.5
     will appear corrupt after an upgrade to MySQL 5.0.6. (The same
     incompatibility will occur for these tables created in MySQL 5.0.6
     after a downgrade to MySQL 5.0.3 to 5.0.5.) If you have such
     tables, check and repair them with *Note `mysql_upgrade':
     mysql-upgrade. after upgrading. See *Note mysql-upgrade::.

   * *Incompatible change*: For user-defined functions, exact-value
     decimal arguments such as `1.3' or *Note `DECIMAL': numeric-types.
     column values were passed as `REAL_RESULT' values prior to MySQL
     5.0.3. As of 5.0.3, they are passed as strings with a type of
     `DECIMAL_RESULT'. If you upgrade to 5.0.3 and find that your UDF
     now receives string values, use the initialization function to
     coerce the arguments to numbers as described in *Note
     udf-arguments::.

   * *Incompatible change*: As of MySQL 5.0.3, the server by default no
     longer loads user-defined functions (UDFs) unless they have at
     least one auxiliary symbol (for example, an `xxx_init' or
     `xxx_deinit' symbol) defined in addition to the main function
     symbol.  This behavior can be overridden with the
     `--allow-suspicious-udfs' option. See *Note udf-security::.

   * *Incompatible change*: The update log has been removed in MySQL
     5.0. If you had enabled it previously, enable the binary log
     instead.

   * *Incompatible change*: Support for the `ISAM' storage engine has
     been removed in MySQL 5.0. If you have any `ISAM' tables, you
     should convert them _before_ upgrading. For example, to convert an
     `ISAM' table to use the `MyISAM' storage engine, use this
     statement:

          ALTER TABLE TBL_NAME ENGINE = MyISAM;

     Use a similar statement for every `ISAM' table in each of your
     databases.

   * *Incompatible change*: Support for `RAID' options in `MyISAM'
     tables has been removed in MySQL 5.0. If you have tables that use
     these options, you should convert them before upgrading. One way
     to do this is to dump them with *Note `mysqldump': mysqldump, edit
     the dump file to remove the `RAID' options in the *Note `CREATE
     TABLE': create-table. statements, and reload the dump file.
     Another possibility is to use `CREATE TABLE NEW_TBL ...  SELECT
     RAID_TBL' to create a new table from the `RAID' table.  However,
     the *Note `CREATE TABLE': create-table.  part of the statement
     must contain sufficient information to re-create column attributes
     as well as indexes, or column attributes may be lost and indexes
     will not appear in the new table. See *Note create-table::.

     The `.MYD' files for `RAID' tables in a given database are stored
     under the database directory in subdirectories that have names
     consisting of two hex digits in the range from `00' to `ff'. After
     converting all tables that use `RAID' options, these `RAID'-related
     subdirectories still will exist but can be removed. Verify that
     they are empty, and then remove them manually. (If they are not
     empty, this indicates that there is some `RAID' table that has not
     been converted.)

   * As of MySQL 5.0.25, the `lc_time_names' system variable specifies
     the locale that controls the language used to display day and
     month names and abbreviations. This variable affects the output
     from the `DATE_FORMAT()', `DAYNAME()' and `MONTHNAME()' functions.
     See *Note locale-support::.

   * In MySQL 5.0.6, binary logging of stored routines and triggers was
     changed. This change has implications for security, replication,
     and data recovery, as discussed in *Note stored-programs-logging::.

   * As of MySQL 5.0.28, *Note `mysqld_safe': mysqld-safe. no longer
     implicitly invokes `mysqld-max' if it exists. Instead, it invokes
     *Note `mysqld': mysqld. unless a `--mysqld' or `--mysqld-version'
     option is given to specify another server explicitly. If you
     previously relied on the implicit invocation of `mysqld-max', you
     should use an appropriate option now.

* SQL Changes *

   * *Known issue*: Prior to MySQL 5.0.46, the parser accepted invalid
     code in SQL condition handlers, leading to server crashes or
     unexpected execution behavior in stored programs. Specifically,
     the parser permitted a condition handler to refer to labels for
     blocks that enclose the handler declaration. This was incorrect
     because block label scope does not include the code for handlers
     declared within the labeled block.

     As of 5.0.46, the parser rejects this invalid construct, but if
     you upgrade in place (without dumping and reloading your
     databases), existing handlers that contain the construct still are
     invalid _even if they appear to function as you expect_ and should
     be rewritten.

     To find affected handlers, use mysqldump to dump all stored
     procedures and functions, triggers, and events. Then attempt to
     reload them into an upgraded server. Handlers that contain illegal
     label references will be rejected.

     For more information about condition handlers and writing them to
     avoid invalid jumps, see *Note declare-handler::.

   * *Known issue*: The fix for Bug #23491 introduced a problem with
     *Note `SHOW CREATE VIEW': show-create-view, which is used by *Note
     `mysqldump': mysqldump. This causes an incompatibility when
     upgrading from versions affected by that bug fix (MySQL 5.0.40
     through 5.0.43, MySQL 5.1.18 through 5.1.19): If you use *Note
     `mysqldump': mysqldump.  before upgrading from an affected version
     and reload the data after upgrading to a higher version, you must
     drop and recreate your views.

   * *Incompatible change*: The parser accepted statements that
     contained `/* ...  */' that were not properly closed with `*/',
     such as `SELECT 1 /* + 2'. As of MySQL 5.0.50, statements that
     contain unclosed `/*'-comments now are rejected with a syntax
     error.

     This fix has the potential to cause incompatibilities.  Because of
     Bug #26302, which caused the trailing `*/' to be truncated from
     comments in views, stored routines, triggers, and events, it is
     possible that objects of those types may have been stored with
     definitions that now will be rejected as syntactically invalid.
     Such objects should be dropped and re-created so that their
     definitions do not contain truncated comments. If a stored object
     definition contains only a single statement (does not use a *Note
     `BEGIN ... END': begin-end. block) and contains a comment within
     the statement, the comment should be moved to follow the statement
     or the object should be rewritten to use a *Note `BEGIN ... END':
     begin-end. block. For example, this statement:

          CREATE PROCEDURE p() SELECT 1 /* my comment */ ;

     Can be rewritten in either of these ways:

          CREATE PROCEDURE p() SELECT 1; /* my comment */
          CREATE PROCEDURE p() BEGIN SELECT 1 /* my comment */ ; END;

   * *Incompatible change*: If you have created a user-defined function
     (UDF) with a given name and upgrade MySQL to a version that
     implements a new built-in function with the same name, the UDF
     becomes inaccessible. To correct this, use *Note `DROP FUNCTION':
     drop-function. to drop the UDF, and then use *Note `CREATE
     FUNCTION': create-function. to re-create the UDF with a different
     nonconflicting name. If a new version of MySQL implements a
     built-in function with the same name as an existing stored
     function, you have two choices: Rename the stored function to use
     a nonconflicting name, or change calls to the function so that
     they use a database qualifier (that is, use `DB_NAME.FUNC_NAME()'
     syntax). See *Note function-resolution::, for the rules describing
     how the server interprets references to different kinds of
     functions.

   * *Incompatible change*: As of MySQL 5.0.15, the `CHAR()' function
     returns a binary string rather than a string in the connection
     character set. An optional `USING CHARSET_NAME' clause may be used
     to produce a result in a specific character set instead. Also,
     arguments larger than 256 produce multiple characters. They are no
     longer interpreted modulo 256 to produce a single character each.
     These changes may cause some incompatibilities:

        * `CHAR(ORD('A')) = 'a'' is no longer true:

               mysql> SELECT CHAR(ORD('A')) = 'a';
               +----------------------+
               | CHAR(ORD('A')) = 'a' |
               +----------------------+
               |                    0 |
               +----------------------+

          To perform a case-insensitive comparison, you can produce a
          result string in a nonbinary character set by adding a
          `USING' clause or converting the result:

               mysql> SELECT CHAR(ORD('A') USING latin1) = 'a';
               +-----------------------------------+
               | CHAR(ORD('A') USING latin1) = 'a' |
               +-----------------------------------+
               |                                 1 |
               +-----------------------------------+
               mysql> SELECT CONVERT(CHAR(ORD('A')) USING latin1) = 'a';
               +--------------------------------------------+
               | CONVERT(CHAR(ORD('A')) USING latin1) = 'a' |
               +--------------------------------------------+
               |                                          1 |
               +--------------------------------------------+

        * *Incompatible change*: Beginning with MySQL 5.0.12, natural
          joins and joins with `USING', including outer join variants,
          are processed according to the SQL:2003 standard. The changes
          include elimination of redundant output columns for `NATURAL'
          joins and joins specified with a `USING' clause and proper
          ordering of output columns. The precedence of the comma
          operator also now is lower compared to `JOIN', `LEFT JOIN',
          and so forth.

          These changes make MySQL more compliant with standard SQL.
          However, they can result in different output columns for some
          joins. Also, some queries that appeared to work correctly
          prior to 5.0.12 must be rewritten to comply with the
          standard. For details about the scope of the changes and
          examples that show what query rewrites are necessary, see
          *Note join::.

        * `CREATE TABLE ... SELECT CHAR(...)' produces a *Note
          `VARBINARY': binary-varbinary.  column, not a *Note
          `VARCHAR': char.  column. To produce a *Note `VARCHAR': char.
          column, use `USING' or `CONVERT()' as just described to
          convert the `CHAR()' result into a nonbinary character set.

        * Previously, the following statements inserted the value
          `0x00410041' (`'AA'' as a `ucs2' string) into the table:

               CREATE TABLE t (ucs2_column CHAR(2) CHARACTER SET ucs2);
               INSERT INTO t VALUES (CHAR(0x41,0x41));

          As of MySQL 5.0.15, the statements insert a single `ucs2'
          character with value `0x4141'.

   * *Incompatible change*: By default, integer subtraction involving
     an unsigned value should produce an unsigned result. Tracking of
     the `unsignedness' of an expression was improved in MySQL 5.0.13.
     This means that, in some cases where an unsigned subtraction would
     have resulted in a signed integer, it now results in an unsigned
     integer. One context in which this difference manifests itself is
     when a subtraction involving an unsigned operand would be negative.

     Suppose that `i' is a `TINYINT UNSIGNED' column and has a value of
     0. The server evaluates the following expression using 64-bit
     unsigned integer arithmetic with the following result:

          mysql> SELECT i - 1 FROM t;
          +----------------------+
          | i - 1                |
          +----------------------+
          | 18446744073709551615 |
          +----------------------+

     If the expression is used in an `UPDATE t SET i = i - 1'
     statement, the expression is evaluated and the result assigned to
     `i' according to the usual rules for handling values outside the
     column range or 0 to 255. That is, the value is clipped to the
     nearest endpoint of the range. However, the result is
     version-specific:

        * Before MySQL 5.0.13, the expression is evaluated but is
          treated as the equivalent 64-bit signed value (-1) for the
          assignment. The value of -1 is clipped to the nearest
          endpoint of the column range, resulting in a value of 0:

               mysql> UPDATE t SET i = i - 1; SELECT i FROM t;
               +------+
               | i    |
               +------+
               |    0 |
               +------+

        * As of MySQL 5.0.13, the expression is evaluated and retains
          its unsigned attribute for the assignment. The value of
          18446744073709551615 is clipped to the nearest endpoint of
          the column range, resulting in a value of 255:

               mysql> UPDATE t SET i = i - 1; SELECT i FROM t;
               +------+
               | i    |
               +------+
               |  255 |
               +------+

     To get the older behavior, use `CAST()' to convert the expression
     result to a signed value:

          UPDATE t SET i = CAST(i - 1 AS SIGNED);

     Alternatively, set the `NO_UNSIGNED_SUBTRACTION' SQL mode.
     However, this will affect all integer subtractions involving
     unsigned values.

   * *Incompatible change*: Before MySQL 5.0.12, `NOW()' and
     `SYSDATE()' return the same value (the time at which the statement
     in which the function occurs begins executing). As of MySQL 5.0.12,
     `SYSDATE()' returns the time at which it executes, which can
     differ from the value returned by `NOW()'. For information about
     the implications for binary logging, replication, and use of
     indexes, see the description for `SYSDATE()' in *Note
     date-and-time-functions:: and for `SET TIMESTAMP' in *Note
     set-option::. To restore the former behavior for `SYSDATE()' and
     cause it to be an alias for `NOW()', start the server with the
     `--sysdate-is-now' option (available as of MySQL 5.0.20).

   * *Incompatible change*: Before MySQL 5.0.13, `GREATEST(X,NULL)' and
     `LEAST(X,NULL)' return X when X is a non-`NULL' value. As of
     5.0.13, both functions return `NULL' if any argument is `NULL',
     the same as Oracle. This change can cause problems for
     applications that rely on the old behavior.

   * *Incompatible change*: Before MySQL 5.0.8, conversion of *Note
     `DATETIME': datetime. values to numeric form by adding zero
     produced a result in `YYYYMMDDHHMMSS' format. The result of
     `DATETIME+0' is now in `YYYYMMDDHHMMSS.000000' format.

   * *Incompatible change*: In MySQL 5.0.6, the behavior of *Note `LOAD
     DATA INFILE': load-data. and *Note `SELECT ... INTO OUTFILE':
     select-into. has changed when the `FIELDS TERMINATED BY' and
     `FIELDS ENCLOSED BY' values both are empty. Formerly, a column was
     read or written using the display width of the column. For
     example, `INT(4)' was read or written using a field with a width
     of 4. Now columns are read and written using a field width wide
     enough to hold all values in the field. However, data files
     written before this change was made might not be reloaded
     correctly with *Note `LOAD DATA INFILE': load-data. for MySQL
     5.0.6 and up. This change also affects data files read by *Note
     `mysqlimport': mysqlimport.  and written by *Note `mysqldump
     --tab': mysqldump, which use *Note `LOAD DATA INFILE': load-data.
     and *Note `SELECT ... INTO OUTFILE': select-into. For more
     information, see *Note load-data::.

   * *Incompatible change*: Before MySQL 5.0.2, *Note `SHOW STATUS':
     show-status.  returned global status values. The default as of
     5.0.2 is to return session values, which is incompatible with
     previous versions. To issue a *Note `SHOW STATUS': show-status.
     statement that will retrieve global status values for all versions
     of MySQL, write it like this:

          SHOW /*!50002 GLOBAL */ STATUS;

   * *Incompatible change*: User variables are not case sensitive in
     MySQL 5.0.  In MySQL 4.1, `SET @x = 0; SET @X = 1; SELECT @x;'
     created two variables and returned `0'. In MySQL 5.0, it creates
     one variable and returns `1'. Replication setups that rely on the
     old behavior may be affected by this change.

   * Some keywords may be reserved in MySQL 5.0 that were not reserved
     in MySQL 4.1. See *Note reserved-words::.

   * The `LOAD DATA FROM MASTER' and `LOAD TABLE FROM MASTER'
     statements are deprecated. See *Note load-data-from-master::, for
     recommended alternatives.

   * As of MySQL 5.0.25, *Note `TIMESTAMP': datetime.  columns that are
     `NOT NULL' now are reported that way by *Note `SHOW COLUMNS':
     show-columns. and `INFORMATION_SCHEMA', rather than as `NULL'.

   * Comparisons made between *Note `FLOAT': numeric-types. or *Note
     `DOUBLE': numeric-types. values that happened to work in MySQL 4.1
     may not do so in 5.0. Values of these types are imprecise in all
     MySQL versions, and you are _strongly advised_ to avoid such
     comparisons as `WHERE COL_NAME=SOME_DOUBLE', _regardless of the
     MySQL version you are using_. See *Note problems-with-float::.

   * As of MySQL 5.0.3, *Note `BIT': numeric-types. is a separate data
     type, not a synonym for `TINYINT(1)'. See *Note
     numeric-type-overview::.

   * MySQL 5.0.2 adds several SQL modes that enable stricter control
     over rejecting records that have invalid or missing values. See
     *Note server-sql-mode::, and *Note constraint-invalid-data::. If
     you want to enable this control but continue to use MySQL's
     capability for storing incorrect dates such as `'2004-02-31'', you
     should start the server with
     `--sql_mode="TRADITIONAL,ALLOW_INVALID_DATES"'.

   * As of MySQL 5.0.2, the `SCHEMA' and `SCHEMAS' keywords are
     accepted as synonyms for `DATABASE' and `DATABASES', respectively.
     (While `schemata' is grammatically correct and even appears in
     some MySQL 5.0 system database and table names, it cannot be used
     as a keyword.)

* C API Changes *

   * *Incompatible change*: Because the MySQL 5.0 server has a new
     implementation of the *Note `DECIMAL': numeric-types. data type, a
     problem may occur if the server is used by older clients that still
     are linked against MySQL 4.1 client libraries. If a client uses
     the binary client/server protocol to execute prepared statements
     that generate result sets containing numeric values, an error will
     be raised: `'Using unsupported buffer type: 246''

     This error occurs because the 4.1 client libraries do not support
     the new `MYSQL_TYPE_NEWDECIMAL' type value added in 5.0. There is
     no way to disable the new *Note `DECIMAL': numeric-types. data
     type on the server side. You can avoid the problem by relinking the
     application with the client libraries from MySQL 5.0.

   * *Incompatible change*: The `ER_WARN_DATA_TRUNCATED' warning symbol
     was renamed to `WARN_DATA_TRUNCATED' in MySQL 5.0.3.

   * The `reconnect' flag in the `MYSQL' structure is set to 0 by *Note
     `mysql_real_connect()': mysql-real-connect. Only those client
     programs which did not explicitly set this flag to 0 or 1 after
     *Note `mysql_real_connect()': mysql-real-connect.  experience a
     change. Having automatic reconnection enabled by default was
     considered too dangerous (due to the fact that table locks,
     temporary tables, user variables, and session variables are lost
     after reconnection).


File: manual.info,  Node: downgrading,  Next: checking-table-incompatibilities,  Prev: upgrading,  Up: upgrading-downgrading

3.19.2 Downgrading MySQL
------------------------

* Menu:

* downgrading-to-previous-series::  Downgrading to MySQL 4.1

This section describes what you should do to downgrade to an older
MySQL version in the unlikely case that the previous version worked
better than the new one.

If you are downgrading within the same release series (for example,
from 4.1.13 to 4.1.12) the general rule is that you just have to
install the new binaries on top of the old ones. There is no need to do
anything with the databases. As always, however, it is always a good
idea to make a backup.

The following items form a checklist of things you should do whenever
you perform a downgrade:

   * Read the upgrading section for the release series from which you
     are downgrading to be sure that it does not have any features you
     really need. See *Note upgrading::.

   * If there is a downgrading section for that version, you should
     read that as well.

   * To see which new features were added between the version to which
     you are downgrading and your current version, see the change logs
     (*Note news::).

   * Check *Note checking-table-incompatibilities::, to see whether
     changes to table formats or to character sets or collations were
     made between your current version of MySQL and the version to
     which you are downgrading. If so and these changes result in an
     incompatibility between MySQL versions, you will need to downgrade
     the affected tables using the instructions in *Note
     rebuilding-tables::.

In most cases, you can move the MySQL format files and data files
between different versions on the same architecture as long as you stay
within versions for the same release series of MySQL.

If you downgrade from one release series to another, there may be
incompatibilities in table storage formats. In this case, use *Note
`mysqldump': mysqldump. to dump your tables before downgrading. After
downgrading, reload the dump file using *Note `mysql': mysql. or *Note
`mysqlimport': mysqlimport. to re-create your tables. For examples, see
*Note copying-databases::.

A typical symptom of a downward-incompatible table format change when
you downgrade is that you cannot open tables. In that case, use the
following procedure:

  1. Stop the older MySQL server that you are downgrading to.

  2. Restart the newer MySQL server you are downgrading from.

  3. Dump any tables that were inaccessible to the older server by
     using *Note `mysqldump': mysqldump. to create a dump file.

  4. Stop the newer MySQL server and restart the older one.

  5. Reload the dump file into the older server. Your tables should be
     accessible.

It might also be the case that system tables in the `mysql' database
have changed and that downgrading introduces some loss of functionality
or requires some adjustments. Here are some examples:

   * Trigger creation requires the `TRIGGER' privilege as of MySQL 5.1.
     In MySQL 5.0, there is no `TRIGGER' privilege and `SUPER' is
     required instead. If you downgrade from MySQL 5.1 to 5.0, you will
     need to give the `SUPER' privilege to those accounts that had the
     `TRIGGER' privilege in 5.1.

   * Triggers were added in MySQL 5.0, so if you downgrade from 5.0 to
     4.1, you cannot use triggers at all.

   * The `mysql.proc.comment' column definition changed between MySQL
     5.1 and 5.5. After a downgrade from 5.5 to 5.1, this table is seen
     as corrupt and in need of repair.  To workaround this problem,
     execute *Note `mysql_upgrade': mysql-upgrade. from the version of
     MySQL to which you downgraded.


File: manual.info,  Node: downgrading-to-previous-series,  Prev: downgrading,  Up: downgrading

3.19.2.1 Downgrading to MySQL 4.1
.................................

MySQL 4.1 does not support stored routines or triggers. If your
databases contain stored routines or triggers, prevent them from being
dumped when you use *Note `mysqldump': mysqldump. by using the
`--skip-routines' and `--skip-triggers' options. (See *Note
mysqldump::.)

MySQL 4.1 does not support views. If your databases contain views,
remove them with *Note `DROP VIEW': drop-view.  before using *Note
`mysqldump': mysqldump. (See *Note drop-view::.)

After downgrading from MySQL 5.0, you may see the following information
in the `mysql.err' file:

     Incorrect information in file: './mysql/user.frm'

In this case, you can do the following:

  1. Start MySQL 5.0.4 (or newer).

  2. Run *Note `mysql_fix_privilege_tables':
     mysql-fix-privilege-tables, which will change the `mysql.user'
     table to a format that both MySQL 4.1 and 5.0 can use.

  3. Stop the MySQL server.

  4. Start MySQL 4.1.

If the preceding procedure fails, you should be able to do the
following instead:

  1. Start MySQL 5.0.4 (or newer).

  2. Run *Note `mysqldump --opt --add-drop-table mysql >
     /tmp/mysql.dump': mysqldump.

  3. Stop the MySQL server.

  4. Start MySQL 4.1 with the `--skip-grant-tables' option.

  5. Run *Note `mysql mysql < /tmp/mysql.dump': mysql.

  6. Run *Note `mysqladmin flush-privileges': mysqladmin.


File: manual.info,  Node: checking-table-incompatibilities,  Next: rebuilding-tables,  Prev: downgrading,  Up: upgrading-downgrading

3.19.3 Checking Whether Tables or Indexes Must Be Rebuilt
---------------------------------------------------------

A binary upgrade or downgrade is one that installs one version of MySQL
`in place' over an existing version, without dumping and reloading
tables:

  1. Stop the server for the existing version if it is running.

  2. Install a different version of MySQL. This is an upgrade if the
     new version is higher than the original version, a downgrade if
     the version is lower.

  3. Start the server for the new version.

In many cases, the tables from the previous version of MySQL can be
used without problem by the new version. However, sometimes changes
occur that require tables or table indexes to be rebuilt, as described
in this section. If you have tables that are affected by any of the
issues described here, rebuild the tables or indexes as necessary using
the instructions given in *Note rebuilding-tables::.

* Table Incompatibilities *

After a binary upgrade to MySQL 5.1 from a MySQL 5.0 installation that
contains *Note `ARCHIVE': archive-storage-engine. tables, accessing
those tables causes the server to crash, even if you have run *Note
`mysql_upgrade': mysql-upgrade. or *Note `CHECK TABLE ... FOR UPGRADE':
check-table. To work around this problem, use *Note `mysqldump':
mysqldump. to dump all *Note `ARCHIVE': archive-storage-engine. tables
before upgrading, and reload them into MySQL 5.1 after upgrading. The
same problem occurs for binary downgrades from MySQL 5.1 to 5.0.

* Index Incompatibilities *

If you perform a binary upgrade without dumping and reloading tables,
you cannot upgrade directly from MySQL 4.1 to 5.1 or higher. This
occurs due to an incompatible change in the `MyISAM' table index format
in MySQL 5.0. Upgrade from MySQL 4.1 to 5.0 and repair all `MyISAM'
tables. Then upgrade from MySQL 5.0 to 5.1 and check and repair your
tables.

Modifications to the handling of character sets or collations might
change the character sort order, which causes the ordering of entries
in any index that uses an affected character set or collation to be
incorrect. Such changes result in several possible problems:

   * Comparison results that differ from previous results

   * Inability to find some index values due to misordered index entries

   * Misordered `ORDER BY' results

   * Tables that *Note `CHECK TABLE': check-table. reports as being in
     need of repair

The solution to these problems is to rebuild any indexes that use an
affected character set or collation, either by dropping and re-creating
the indexes, or by dumping and reloading the entire table. For
information about rebuilding indexes, see *Note rebuilding-tables::.

To check whether a table has indexes that must be rebuilt, consult the
following list. It indicates which versions of MySQL introduced
character set or collation changes that require indexes to be rebuilt.
Each entry indicates the version in which the change occurred and the
character sets or collations that the change affects. If the change is
associated with a particular bug report, the bug number is given.

The list applies both for binary upgrades and downgrades. For example,
Bug #27877 was fixed in MySQL 5.1.24 and 5.4.0, so it applies to
upgrades from versions older than 5.1.24 to 5.1.24 or newer, and to
downgrades from 5.1.24 or newer to versions older than 5.1.24.

In many cases, you can use *Note `CHECK TABLE ... FOR UPGRADE':
check-table. to identify tables for which index rebuilding is required.
(It will report: `Table upgrade required. Please do "REPAIR TABLE
`tbl_name`" to fix it!') In these cases, you can also use *Note
`mysqlcheck --check-upgrade': mysqlcheck. or *Note `mysql_upgrade':
mysql-upgrade, which execute *Note `CHECK TABLE': check-table. However,
the use of *Note `CHECK TABLE': check-table. applies only after
upgrades, not downgrades. Also, *Note `CHECK TABLE': check-table. is
not applicable to all storage engines. For details about which storage
engines *Note `CHECK TABLE': check-table. supports, see *Note
check-table::.

Changes that cause index rebuilding to be necessary:

   * MySQL 5.0.48, 5.1.21 (Bug #29461)

     Affects indexes for columns that use any of these character sets:
     `eucjpms', `euc_kr', `gb2312', `latin7', `macce', `ujis'

     Affected tables can be detected by *Note `CHECK TABLE ... FOR
     UPGRADE': check-table. as of MySQL 5.1.29, 5.4.0 (see Bug #39585).

   * MySQL 5.0.48, 5.1.23 (Bug #27562)

     Affects indexes that use the `ascii_general_ci' collation for
     columns that contain any of these characters: `'`'' GRAVE ACCENT,
     `'['' LEFT SQUARE BRACKET, `'\'' REVERSE SOLIDUS, `']'' RIGHT
     SQUARE BRACKET, `'~'' TILDE

     Affected tables can be detected by *Note `CHECK TABLE ... FOR
     UPGRADE': check-table. as of MySQL 5.1.29, 5.4.0 (see Bug #39585).

   * MySQL 5.1.24, 5.4.0 (Bug #27877)

     Affects indexes that use the `utf8_general_ci' or
     `ucs2_general_ci' collation for columns that contain `'ss'' LATIN
     SMALL LETTER SHARP S (German).

     Affected tables can be detected by *Note `CHECK TABLE ... FOR
     UPGRADE': check-table. as of MySQL 5.1.30, 5.4.0 (see Bug #40053).


File: manual.info,  Node: rebuilding-tables,  Next: copying-databases,  Prev: checking-table-incompatibilities,  Up: upgrading-downgrading

3.19.4 Rebuilding or Repairing Tables or Indexes
------------------------------------------------

This section describes how to rebuild a table. This can be necessitated
by changes to MySQL such as how data types are handled or changes to
character set handling. For example, an error in a collation might have
been corrected, necessitating a table rebuild to update the indexes for
character columns that use the collation. (For examples, see *Note
checking-table-incompatibilities::.) It might also be that a table
repair or upgrade should be done as indicated by a table check
operation such as that performed by `CHECK TABLE', *Note `mysqlcheck':
mysqlcheck, or *Note `mysql_upgrade': mysql-upgrade.

Methods for rebuilding a table include dumping and reloading it, or
using *Note `ALTER TABLE': alter-table. or *Note `REPAIR TABLE':
repair-table.

*Note*:

If you are rebuilding tables because a different version of MySQL will
not handle them after a binary (in-place) upgrade or downgrade, you
must use the dump-and-reload method. Dump the tables _before_ upgrading
or downgrading using your original version of MySQL. Then reload the
tables _after_ upgrading or downgrading.

If you use the dump-and-reload method of rebuilding tables only for the
purpose of rebuilding indexes, you can perform the dump either before
or after upgrading or downgrading. Reloading still must be done
afterward.

To rebuild a table by dumping and reloading it, use *Note `mysqldump':
mysqldump. to create a dump file and *Note `mysql': mysql. to reload
the file:

     shell> mysqldump DB_NAME t1 > dump.sql
     shell> mysql DB_NAME < dump.sql

To rebuild all the tables in a single database, specify the database
name without any following table name:

     shell> mysqldump DB_NAME > dump.sql
     shell> mysql DB_NAME < dump.sql

To rebuild all tables in all databases, use the `--all-databases'
option:

     shell> mysqldump --all-databases > dump.sql
     shell> mysql < dump.sql

To rebuild a table with *Note `ALTER TABLE': alter-table, use a `null'
alteration; that is, an *Note `ALTER TABLE': alter-table. statement that
`changes' the table to use the storage engine that it already has. For
example, if `t1' is a `MyISAM' table, use this statement:

     mysql> ALTER TABLE t1 ENGINE = MyISAM;

If you are not sure which storage engine to specify in the *Note `ALTER
TABLE': alter-table. statement, use *Note `SHOW CREATE TABLE':
show-create-table. to display the table definition.

If you must rebuild a table because a table checking operation
indicates that the table is corrupt or needs an upgrade, you can use
*Note `REPAIR TABLE': repair-table. if that statement supports the
table's storage engine. For example, to repair a `MyISAM' table, use
this statement:

     mysql> REPAIR TABLE t1;

For storage engines such as `InnoDB' that *Note `REPAIR TABLE':
repair-table. does not support, use *Note `mysqldump': mysqldump. to
create a dump file and *Note `mysql': mysql. to reload the file, as
described earlier.

For specifics about which storage engines *Note `REPAIR TABLE':
repair-table. supports, see *Note repair-table::.

*Note `mysqlcheck --repair': mysqlcheck. provides command-line access
to the *Note `REPAIR TABLE': repair-table.  statement. This can be a
more convenient means of repairing tables because you can use the
`--databases' or `--all-databases' option to repair all tables in
specific databases or all databases, respectively:

     shell> mysqlcheck --repair --databases DB_NAME ...
     shell> mysqlcheck --repair --all-databases


File: manual.info,  Node: copying-databases,  Prev: rebuilding-tables,  Up: upgrading-downgrading

3.19.5 Copying MySQL Databases to Another Machine
-------------------------------------------------

You can copy the `.frm', `.MYI', and `.MYD' files for `MyISAM' tables
between different architectures that support the same floating-point
format. (MySQL takes care of any byte-swapping issues.) See *Note
myisam-storage-engine::.

In cases where you need to transfer databases between different
architectures, you can use *Note `mysqldump': mysqldump. to create a
file containing SQL statements. You can then transfer the file to the
other machine and feed it as input to the *Note `mysql': mysql. client.

Use *Note `mysqldump --help': mysqldump. to see what options are
available.

The easiest (although not the fastest) way to move a database between
two machines is to run the following commands on the machine on which
the database is located:

     shell> mysqladmin -h 'OTHER_HOSTNAME' create DB_NAME
     shell> mysqldump DB_NAME | mysql -h 'OTHER_HOSTNAME' DB_NAME

If you want to copy a database from a remote machine over a slow
network, you can use these commands:

     shell> mysqladmin create DB_NAME
     shell> mysqldump -h 'OTHER_HOSTNAME' --compress DB_NAME | mysql DB_NAME

You can also store the dump in a file, transfer the file to the target
machine, and then load the file into the database there.  For example,
you can dump a database to a compressed file on the source machine like
this:

     shell> mysqldump --quick DB_NAME | gzip > DB_NAME.gz

Transfer the file containing the database contents to the target
machine and run these commands there:

     shell> mysqladmin create DB_NAME
     shell> gunzip < DB_NAME.gz | mysql DB_NAME

You can also use *Note `mysqldump': mysqldump. and *Note `mysqlimport':
mysqlimport. to transfer the database. For large tables, this is much
faster than simply using *Note `mysqldump': mysqldump. In the following
commands, DUMPDIR represents the full path name of the directory you
use to store the output from *Note `mysqldump': mysqldump.

First, create the directory for the output files and dump the database:

     shell> mkdir DUMPDIR
     shell> mysqldump --tab=DUMPDIR DB_NAME

Then transfer the files in the DUMPDIR directory to some corresponding
directory on the target machine and load the files into MySQL there:

     shell> mysqladmin create DB_NAME           # create database
     shell> cat DUMPDIR/*.sql | mysql DB_NAME   # create tables in database
     shell> mysqlimport DB_NAME DUMPDIR/*.txt   # load data into tables

Do not forget to copy the `mysql' database because that is where the
grant tables are stored. You might have to run commands as the MySQL
`root' user on the new machine until you have the `mysql' database in
place.

After you import the `mysql' database on the new machine, execute *Note
`mysqladmin flush-privileges': mysqladmin. so that the server reloads
the grant table information.


File: manual.info,  Node: operating-system-specific-notes,  Next: environment-variables,  Prev: upgrading-downgrading,  Up: installing

3.20 Operating System-Specific Notes
====================================

* Menu:

* linux::                        Linux Notes
* macosx::                       Mac OS X Notes
* solaris::                      Solaris Notes
* bsd-notes::                    BSD Notes
* other-unix-notes::             Other Unix Notes
* os-2::                         OS/2 Notes


File: manual.info,  Node: linux,  Next: macosx,  Prev: operating-system-specific-notes,  Up: operating-system-specific-notes

3.20.1 Linux Notes
------------------

* Menu:

* linux-os::                     Linux Operating System Notes
* binary-notes-linux::           Linux Binary Distribution Notes
* source-notes-linux::           Linux Source Distribution Notes
* linux-postinstallation::       Linux Postinstallation Notes
* linux-x86::                    Linux x86 Notes
* linux-sparc::                  Linux SPARC Notes
* linux-alpha::                  Linux Alpha Notes
* linux-powerpc::                Linux PowerPC Notes
* linux-mips::                   Linux MIPS Notes
* linux-ia-64::                  Linux IA-64 Notes
* selinux::                      SELinux Notes

This section discusses issues that have been found to occur on Linux.
The first few subsections describe general operating system-related
issues, problems that can occur when using binary or source
distributions, and postinstallation issues. The remaining subsections
discuss problems that occur with Linux on specific platforms.

Note that most of these problems occur on older versions of Linux. If
you are running a recent version, you may see none of them.


File: manual.info,  Node: linux-os,  Next: binary-notes-linux,  Prev: linux,  Up: linux

3.20.1.1 Linux Operating System Notes
.....................................

MySQL needs at least Linux version 2.0.

*Warning*:

We have seen some strange problems with Linux 2.2.14 and MySQL on SMP
systems. We also have reports from some MySQL users that they have
encountered serious stability problems using MySQL with kernel 2.2.14.
If you are using this kernel, you should upgrade to 2.2.19 (or newer)
or to a 2.4 kernel. If you have a multiple-CPU box, you should seriously
consider using 2.4 because it gives you a significant speed boost. Your
system should be more stable.

When using LinuxThreads, you should see a minimum of three *Note
`mysqld': mysqld. processes running. These are in fact threads. There
is one thread for the LinuxThreads manager, one thread to handle
connections, and one thread to handle alarms and signals.


File: manual.info,  Node: binary-notes-linux,  Next: source-notes-linux,  Prev: linux-os,  Up: linux

3.20.1.2 Linux Binary Distribution Notes
........................................

The Linux-Intel binary and RPM releases of MySQL are configured for the
highest possible speed. We are always trying to use the fastest stable
compiler available.

The binary release is linked with `-static', which means you do not
normally need to worry about which version of the system libraries you
have. You need not install LinuxThreads, either. A program linked with
`-static' is slightly larger than a dynamically linked program, but
also slightly faster (3% to 5%). However, one problem with a statically
linked program is that you can't use user-defined functions (UDFs). If
you are going to write or use UDFs (this is something for C or C++
programmers only), you must compile MySQL yourself using dynamic
linking.

A known issue with binary distributions is that on older Linux systems
that use `libc' (such as Red Hat 4.x or Slackware), you get some
(nonfatal) issues with host name resolution. If your system uses `libc'
rather than `glibc2', you probably will encounter some difficulties
with host name resolution and `getpwnam()'. This happens because
`glibc' (unfortunately) depends on some external libraries to implement
host name resolution and `getpwent()', even when compiled with
`-static'. These problems manifest themselves in two ways:

   * You may see the following error message when you run *Note
     `mysql_install_db': mysql-install-db.:

          Sorry, the host 'XXXX' could not be looked up

     You can deal with this by executing *Note `mysql_install_db
     --force': mysql-install-db, which does not execute the *Note
     `resolveip': resolveip. test in *Note `mysql_install_db':
     mysql-install-db. The downside is that you cannot use host names
     in the grant tables: except for `localhost', you must use IP
     addresses instead. If you are using an old version of MySQL that
     does not support `--force', you must manually remove the
     `resolveip' test in *Note `mysql_install_db': mysql-install-db.
     using a text editor.

   * You also may see the following error when you try to run *Note
     `mysqld': mysqld. with the `--user' option:

          getpwnam: No such file or directory

     To work around this problem, start *Note `mysqld': mysqld. by
     using the `su' command rather than by specifying the `--user'
     option. This causes the system itself to change the user ID of the
     *Note `mysqld': mysqld. process so that *Note `mysqld': mysqld.
     need not do so.

Another solution, which solves both problems, is not to use a binary
distribution. Obtain a MySQL source distribution (in RPM or `.tar.gz'
format) and install that instead.

On some Linux 2.2 versions, you may get the error `Resource temporarily
unavailable' when clients make a great many new connections to a *Note
`mysqld': mysqld. server over TCP/IP. The problem is that Linux has a
delay between the time that you close a TCP/IP socket and the time that
the system actually frees it.  There is room for only a finite number
of TCP/IP slots, so you encounter the resource-unavailable error if
clients attempt too many new TCP/IP connections over a short period of
time.  For example, you may see the error when you run the MySQL
`test-connect' benchmark over TCP/IP.

We have inquired about this problem a few times on different Linux
mailing lists but have never been able to find a suitable resolution.
The only known `fix' is for clients to use persistent connections, or,
if you are running the database server and clients on the same machine,
to use Unix socket file connections rather than TCP/IP connections.


File: manual.info,  Node: source-notes-linux,  Next: linux-postinstallation,  Prev: binary-notes-linux,  Up: linux

3.20.1.3 Linux Source Distribution Notes
........................................

The following notes regarding `glibc' apply only to the situation when
you build MySQL yourself. If you are running Linux on an x86 machine,
in most cases it is much better for you to use our binary. We link our
binaries against the best patched version of `glibc' we can find and
with the best compiler options, in an attempt to make it suitable for a
high-load server. For a typical user, even for setups with a lot of
concurrent connections or tables exceeding the 2GB limit, our binary is
the best choice in most cases. After reading the following text, if you
are in doubt about what to do, try our binary first to determine
whether it meets your needs. If you discover that it is not good enough,
you may want to try your own build. In that case, we would appreciate a
note about it so that we can build a better binary next time.

MySQL uses LinuxThreads on Linux. If you are using an old Linux version
that doesn't have `glibc2', you must install LinuxThreads before trying
to compile MySQL. You can obtain LinuxThreads from
`http://dev.mysql.com/downloads/os-linux.html'.

Note that `glibc' versions before and including version 2.1.1 have a
fatal bug in `pthread_mutex_timedwait()' handling, which is used when
*Note `INSERT DELAYED': insert-delayed.  statements are issued. Do not
use *Note `INSERT DELAYED': insert-delayed. before upgrading `glibc'.

Note that Linux kernel and the LinuxThread library can by default
handle a maximum of 1,024 threads. If you plan to have more than 1,000
concurrent connections, you need to make some changes to LinuxThreads,
as follows:

   * Increase `PTHREAD_THREADS_MAX' in
     `sysdeps/unix/sysv/linux/bits/local_lim.h' to 4096 and decrease
     `STACK_SIZE' in `linuxthreads/internals.h' to 256KB.  The paths
     are relative to the root of `glibc'. (Note that MySQL is not stable
     with 600 to 1000 connections if `STACK_SIZE' is the default of
     2MB.)

   * Recompile LinuxThreads to produce a new `libpthread.a' library,
     and relink MySQL against it.

There is another issue that greatly hurts MySQL performance, especially
on SMP systems. The mutex implementation in LinuxThreads in `glibc' 2.1
is very poor for programs with many threads that hold the mutex only
for a short time. This produces a paradoxical result: If you link MySQL
against an unmodified LinuxThreads, removing processors from an SMP
actually improves MySQL performance in many cases.  We have made a
patch available for `glibc' 2.1.3 to correct this behavior
(`http://dev.mysql.com/Downloads/Linux/linuxthreads-2.1-patch').

With `glibc' 2.2.2, MySQL uses the adaptive mutex, which is much better
than even the patched one in `glibc' 2.1.3. Be warned, however, that
under some conditions, the current mutex code in `glibc' 2.2.2
overspins, which hurts MySQL performance. The likelihood that this
condition occurs can be reduced by re-nicing the *Note `mysqld':
mysqld. process to the highest priority. We have also been able to
correct the overspin behavior with a patch, available at
`http://dev.mysql.com/Downloads/Linux/linuxthreads-2.2.2.patch'.  It
combines the correction of overspin, maximum number of threads, and
stack spacing all in one. You need to apply it in the `linuxthreads'
directory with `patch -p0 </tmp/linuxthreads-2.2.2.patch'. We hope it is
included in some form in future releases of `glibc' 2.2. In any case,
if you link against `glibc' 2.2.2, you still need to correct
`STACK_SIZE' and `PTHREAD_THREADS_MAX'. We hope that the defaults is
corrected to some more acceptable values for high-load MySQL setup in
the future, so that the commands needed to produce your own build can
be reduced to `./configure; make; make install'.

If you use these patches to build a special static version of
`libpthread.a', use it only for statically linking against MySQL. We
know that these patches are safe for MySQL and significantly improve
its performance, but we cannot say anything about their effects on
other applications. If you link other applications that require
LinuxThreads against the patched static version of the library, or
build a patched shared version and install it on your system, you do so
at your own risk.

If you experience any strange problems during the installation of
MySQL, or with some common utilities hanging, it is very likely that
they are either library or compiler related. If this is the case, using
our binary resolves them.

If you link your own MySQL client programs, you may see the following
error at runtime:

     ld.so.1: fatal: libmysqlclient.so.#:
     open failed: No such file or directory

This problem can be avoided by one of the following methods:

   * Link clients with the `-Wl,r/full/path/to/libmysqlclient.so' flag
     rather than with `-Lpath').

   * Copy `libmysqclient.so' to `/usr/lib'.

   * Add the path name of the directory where `libmysqlclient.so' is
     located to the `LD_RUN_PATH' environment variable before running
     your client.

If you are using the Fujitsu compiler (`fcc/FCC'), you may have some
problems compiling MySQL because the Linux header files are very `gcc'
oriented. The following `configure' line should work with `fcc/FCC':

     CC=fcc CFLAGS="-O -K fast -K lib -K omitfp -Kpreex -D_GNU_SOURCE \
         -DCONST=const -DNO_STRTOLL_PROTO" \
     CXX=FCC CXXFLAGS="-O -K fast -K lib \
         -K omitfp -K preex --no_exceptions --no_rtti -D_GNU_SOURCE \
         -DCONST=const -Dalloca=__builtin_alloca -DNO_STRTOLL_PROTO \
         '-D_EXTERN_INLINE=static __inline'" \
     ./configure \
         --prefix=/usr/local/mysql --enable-assembler \
         --with-mysqld-ldflags=-all-static --disable-shared \
         --with-low-memory


File: manual.info,  Node: linux-postinstallation,  Next: linux-x86,  Prev: source-notes-linux,  Up: linux

3.20.1.4 Linux Postinstallation Notes
.....................................

*Note `mysql.server': mysql-server. can be found in the `support-files'
directory under the MySQL installation directory or in a MySQL source
tree. You can install it as `/etc/init.d/mysql' for automatic MySQL
startup and shutdown. See *Note automatic-start::.

If MySQL cannot open enough files or connections, it may be that you
have not configured Linux to handle enough files.

In Linux 2.2 and onward, you can check the number of allocated file
handles as follows:

     shell> cat /proc/sys/fs/file-max
     shell> cat /proc/sys/fs/dquot-max
     shell> cat /proc/sys/fs/super-max

If you have more than 16MB of memory, you should add something like the
following to your init scripts (for example, `/etc/init.d/boot.local'
on SuSE Linux):

     echo 65536 > /proc/sys/fs/file-max
     echo 8192 > /proc/sys/fs/dquot-max
     echo 1024 > /proc/sys/fs/super-max

You can also run the `echo' commands from the command line as `root',
but these settings are lost the next time your computer restarts.

Alternatively, you can set these parameters on startup by using the
`sysctl' tool, which is used by many Linux distributions (including
SuSE Linux 8.0 and later).  Put the following values into a file named
`/etc/sysctl.conf':

     # Increase some values for MySQL
     fs.file-max = 65536
     fs.dquot-max = 8192
     fs.super-max = 1024

You should also add the following to `/etc/my.cnf':

     [mysqld_safe]
     open-files-limit=8192

This should enable a server limit of 8,192 for the combined number of
connections and open files.

The `STACK_SIZE' constant in LinuxThreads controls the spacing of
thread stacks in the address space. It needs to be large enough so that
there is plenty of room for each individual thread stack, but small
enough to keep the stack of some threads from running into the global
*Note `mysqld': mysqld. data. Unfortunately, as we have experimentally
discovered, the Linux implementation of `mmap()' successfully unmaps a
mapped region if you ask it to map out an address currently in use,
zeroing out the data on the entire page instead of returning an error.
So, the safety of *Note `mysqld': mysqld. or any other threaded
application depends on the `gentlemanly' behavior of the code that
creates threads. The user must take measures to make sure that the
number of running threads at any given time is sufficiently low for
thread stacks to stay away from the global heap. With *Note `mysqld':
mysqld, you should enforce this behavior by setting a reasonable value
for the `max_connections' variable.

If you build MySQL yourself, you can patch LinuxThreads for better
stack use. See *Note source-notes-linux::. If you do not want to patch
LinuxThreads, you should set `max_connections' to a value no higher
than 500. It should be even less if you have a large key buffer, large
heap tables, or some other things that make *Note `mysqld': mysqld.
allocate a lot of memory, or if you are running a 2.2 kernel with a 2GB
patch. If you are using our binary or RPM version, you can safely set
`max_connections' at 1500, assuming no large key buffer or heap tables
with lots of data.  The more you reduce `STACK_SIZE' in LinuxThreads
the more threads you can safely create. Values between 128KB and 256KB
are recommended.

If you use a lot of concurrent connections, you may suffer from a
`feature' in the 2.2 kernel that attempts to prevent fork bomb attacks
by penalizing a process for forking or cloning a child. This causes
MySQL not to scale well as you increase the number of concurrent
clients. On single-CPU systems, we have seen this manifest as very slow
thread creation; it may take a long time to connect to MySQL (as long
as one minute), and it may take just as long to shut it down. On
multiple-CPU systems, we have observed a gradual drop in query speed as
the number of clients increases. In the process of trying to find a
solution, we have received a kernel patch from one of our users who
claimed it helped for his site. This patch is available at
`http://dev.mysql.com/Downloads/Patches/linux-fork.patch'.  We have
done rather extensive testing of this patch on both development and
production systems. It has significantly improved MySQL performance
without causing any problems and is recommended for users who still run
high-load servers on 2.2 kernels.

This issue has been fixed in the 2.4 kernel, so if you are not
satisfied with the current performance of your system, rather than
patching your 2.2 kernel, it might be easier to upgrade to 2.4. On SMP
systems, upgrading also gives you a nice SMP boost in addition to
fixing the fairness bug.

We have tested MySQL on the 2.4 kernel on a two-CPU machine and found
MySQL scales _much_ better. There was virtually no slowdown on query
throughput all the way up to 1,000 clients, and the MySQL scaling
factor (computed as the ratio of maximum throughput to the throughput
for one client) was 180%. We have observed similar results on a
four-CPU system: Virtually no slowdown as the number of clients was
increased up to 1,000, and a 300% scaling factor.  Based on these
results, for a high-load SMP server using a 2.2 kernel, it is
definitely recommended to upgrade to the 2.4 kernel at this point.

We have discovered that it is essential to run the *Note `mysqld':
mysqld. process with the highest possible priority on the 2.4 kernel to
achieve maximum performance.  This can be done by adding a `renice -20
$$' command to *Note `mysqld_safe': mysqld-safe. In our testing on a
four-CPU machine, increasing the priority resulted in a 60% throughput
increase with 400 clients.

We are currently also trying to collect more information on how well
MySQL performs with a 2.4 kernel on four-way and eight-way systems. If
you have access such a system and have done some benchmarks, please
send an email message to <benchmarks@mysql.com> with the results. We
will review them for inclusion in the manual.

If you see a dead *Note `mysqld': mysqld. server process with `ps',
this usually means that you have found a bug in MySQL or you have a
corrupted table. See *Note crashing::.

To get a core dump on Linux if *Note `mysqld': mysqld. dies with a
`SIGSEGV' signal, you can start *Note `mysqld': mysqld. with the
`--core-file' option. Note that you also probably need to raise the
core file size by adding `ulimit -c 1000000' to *Note `mysqld_safe':
mysqld-safe. or starting *Note `mysqld_safe': mysqld-safe. with
`--core-file-size=1000000'.  See *Note mysqld-safe::.


File: manual.info,  Node: linux-x86,  Next: linux-sparc,  Prev: linux-postinstallation,  Up: linux

3.20.1.5 Linux x86 Notes
........................

MySQL requires `libc' 5.4.12 or newer. It is known to work with `libc'
5.4.46.  `glibc' 2.0.6 and later should also work.  There have been
some problems with the `glibc' RPMs from Red Hat, so if you have
problems, check whether there are any updates. The `glibc' 2.0.7-19 and
2.0.7-29 RPMs are known to work.

If you are using Red Hat 8.0 or a new `glibc' 2.2.x library, you may
see *Note `mysqld': mysqld. die in `gethostbyaddr()'. This happens
because the new `glibc' library requires a stack size greater than
128KB for this call. To fix the problem, start *Note `mysqld': mysqld.
with the `--thread-stack=192K' option.  This stack size is the default
on MySQL 4.0.10 and above, so you should not see the problem.

If you are using `gcc' 3.0 and above to compile MySQL, you must install
the `libstdc++v3' library before compiling MySQL; if you do not do
this, you get an error about a missing `__cxa_pure_virtual' symbol
during linking.

On some older Linux distributions, `configure' may produce an error
like this:

     Syntax error in sched.h. Change _P to __P in the
     /usr/include/sched.h file.
     See the Installation chapter in the Reference Manual.

Just do what the error message says. Add an extra underscore to the
`_P' macro name that has only one underscore, and then try again.

You may get some warnings when compiling. Those shown here can be
ignored:

     mysqld.cc -o objs-thread/mysqld.o
     mysqld.cc: In function `void init_signals()':
     mysqld.cc:315: warning: assignment of negative value `-1' to
     `long unsigned int'
     mysqld.cc: In function `void * signal_hand(void *)':
     mysqld.cc:346: warning: assignment of negative value `-1' to
     `long unsigned int'

If *Note `mysqld': mysqld. always dumps core when it starts, the
problem may be that you have an old `/lib/libc.a'. Try renaming it, and
then remove `sql/mysqld' and do a new `make install' and try again.
This problem has been reported on some Slackware installations.

If you get the following error when linking *Note `mysqld': mysqld, it
means that your `libg++.a' is not installed correctly:

     /usr/lib/libc.a(putc.o): In function `_IO_putc':
     putc.o(.text+0x0): multiple definition of `_IO_putc'

You can avoid using `libg++.a' by running `configure' like this:

     shell> CXX=gcc ./configure


File: manual.info,  Node: linux-sparc,  Next: linux-alpha,  Prev: linux-x86,  Up: linux

3.20.1.6 Linux SPARC Notes
..........................

In some implementations, `readdir_r()' is broken. The symptom is that
the *Note `SHOW DATABASES': show-databases. statement always returns an
empty set.  This can be fixed by removing `HAVE_READDIR_R' from
`config.h' after configuring and before compiling.


File: manual.info,  Node: linux-alpha,  Next: linux-powerpc,  Prev: linux-sparc,  Up: linux

3.20.1.7 Linux Alpha Notes
..........................

We have tested MySQL 5.0 on Alpha with our benchmarks and test suite,
and it appears to work well.

We currently build the MySQL binary packages on SuSE Linux 7.0 for AXP,
kernel 2.4.4-SMP, Compaq C compiler (V6.2-505) and Compaq C++ compiler
(V6.3-006) on a Compaq DS20 machine with an Alpha EV6 processor.

You can find the preceding compilers at
`http://www.support.compaq.com/alpha-tools/'. By using these compilers
rather than `gcc', we get about 9% to 14% better MySQL performance.

For MySQL on Alpha, we use the `-arch generic' flag to our compile
options, which ensures that the binary runs on all Alpha processors. We
also compile statically to avoid library problems. The `configure'
command looks like this:

     CC=ccc CFLAGS="-fast -arch generic" CXX=cxx \
     CXXFLAGS="-fast -arch generic -noexceptions -nortti" \
     ./configure --prefix=/usr/local/mysql --disable-shared \
         --with-extra-charsets=complex --enable-thread-safe-client \
         --with-mysqld-ldflags=-non_shared --with-client-ldflags=-non_shared

Some known problems when running MySQL on Linux-Alpha:

   * Debugging threaded applications like MySQL does not work with `gdb
     4.18'. You should use `gdb' 5.1 instead.

   * If you try linking *Note `mysqld': mysqld. statically when using
     `gcc', the resulting image dumps core at startup time. In other
     words, _do not_ use `--with-mysqld-ldflags=-all-static' with `gcc'.


File: manual.info,  Node: linux-powerpc,  Next: linux-mips,  Prev: linux-alpha,  Up: linux

3.20.1.8 Linux PowerPC Notes
............................

MySQL should work on MkLinux with the newest `glibc' package (tested
with `glibc' 2.0.7).


File: manual.info,  Node: linux-mips,  Next: linux-ia-64,  Prev: linux-powerpc,  Up: linux

3.20.1.9 Linux MIPS Notes
.........................

To get MySQL to work on Qube2 (Linux Mips), you need the newest `glibc'
libraries.  `glibc-2.0.7-29C2' is known to work. You must also use
`gcc' 2.95.2 or newer).


File: manual.info,  Node: linux-ia-64,  Next: selinux,  Prev: linux-mips,  Up: linux

3.20.1.10 Linux IA-64 Notes
...........................

To get MySQL to compile on Linux IA-64, we use the following
`configure' command for building with `gcc' 2.96:

     CC=gcc \
     CFLAGS="-O3 -fno-omit-frame-pointer" \
     CXX=gcc \
     CXXFLAGS="-O3 -fno-omit-frame-pointer -felide-constructors \
         -fno-exceptions -fno-rtti" \
         ./configure --prefix=/usr/local/mysql \
         "--with-comment=Official MySQL binary" \
         --with-extra-charsets=complex

On IA-64, the MySQL client binaries use shared libraries. This means
that if you install our binary distribution at a location other than
`/usr/local/mysql', you need to add the path of the directory where you
have `libmysqlclient.so' installed either to the `/etc/ld.so.conf' file
or to the value of your `LD_LIBRARY_PATH' environment variable.

See *Note c-api-linking-problems::.


File: manual.info,  Node: selinux,  Prev: linux-ia-64,  Up: linux

3.20.1.11 SELinux Notes
.......................

RHEL4 comes with SELinux, which supports tighter access control for
processes. If SELinux is enabled (`SELINUX' in `/etc/selinux/config' is
set to `enforcing', `SELINUXTYPE' is set to either `targeted' or
`strict'), you might encounter problems installing Oracle Corporation
RPM packages.

Red Hat has an update that solves this. It involves an update of the
`security policy' specification to handle the install structure of the
RPMs provided by Oracle Corporation. For further information, see
`https://bugzilla.redhat.com/bugzilla/show_bug.cgi?id=167551' and
`http://rhn.redhat.com/errata/RHBA-2006-0049.html'.


File: manual.info,  Node: macosx,  Next: solaris,  Prev: linux,  Up: operating-system-specific-notes

3.20.2 Mac OS X Notes
---------------------

* Menu:

* macosx-10-x::                  Mac OS X 10.x (Darwin)
* macosx-server::                Mac OS X Server 1.2 (Rhapsody)

On Mac OS X, `tar' cannot handle long file names. If you need to unpack
a `.tar.gz' distribution, use `gnutar' instead.


File: manual.info,  Node: macosx-10-x,  Next: macosx-server,  Prev: macosx,  Up: macosx

3.20.2.1 Mac OS X 10.x (Darwin)
...............................

MySQL should work without major problems on Mac OS X 10.x (Darwin).

Known issues:

   * If you have problems with performance under heavy load, try using
     the `--skip-thread-priority' option to *Note `mysqld': mysqld.
     This runs all threads with the same priority. On Mac OS X, this
     gives better performance, at least until Apple fixes its thread
     scheduler.

   * The connection times (`wait_timeout', `interactive_timeout' and
     `net_read_timeout') values are not honored.

     This is probably a signal handling problem in the thread library
     where the signal doesn't break a pending read and we hope that a
     future update to the thread libraries will fix this.

Our binary for Mac OS X is compiled on Darwin 6.3 with the following
`configure' line:

     CC=gcc CFLAGS="-O3 -fno-omit-frame-pointer" CXX=gcc \
     CXXFLAGS="-O3 -fno-omit-frame-pointer -felide-constructors \
         -fno-exceptions -fno-rtti" \
         ./configure --prefix=/usr/local/mysql \
         --with-extra-charsets=complex --enable-thread-safe-client \
         --enable-local-infile --disable-shared

See *Note macosx-installation::.


File: manual.info,  Node: macosx-server,  Prev: macosx-10-x,  Up: macosx

3.20.2.2 Mac OS X Server 1.2 (Rhapsody)
.......................................

For current versions of Mac OS X Server, no operating system changes
are necessary before compiling MySQL. Compiling for the Server platform
is the same as for the client version of Mac OS X.

For older versions (Mac OS X Server 1.2, a.k.a. Rhapsody), you must
first install a pthread package before trying to configure MySQL.

See *Note macosx-installation::.


File: manual.info,  Node: solaris,  Next: bsd-notes,  Prev: macosx,  Up: operating-system-specific-notes

3.20.3 Solaris Notes
--------------------

* Menu:

* solaris-2-7::                  Solaris 2.7/2.8 Notes
* solaris-x86::                  Solaris x86 Notes

For information about installing MySQL on Solaris using PKG
distributions, see *Note solaris-installation::.

On Solaris, you may run into trouble even before you get the MySQL
distribution unpacked, as the Solaris `tar' cannot handle long file
names. This means that you may see errors when you try to unpack MySQL.

If this occurs, you must use GNU `tar' (`gtar') to unpack the
distribution.

If you get the following error from `configure', it means that you have
something wrong with your compiler installation:

     checking for restartable system calls... configure: error can not
     run test programs while cross compiling

In this case, you should upgrade your compiler to a newer version. You
may also be able to solve this problem by inserting the following row
into the `config.cache' file:

     ac_cv_sys_restartable_syscalls=${ac_cv_sys_restartable_syscalls='no'}

If you are using Solaris on a SPARC, the recommended compiler is `gcc'
2.95.2 or 3.2. You can find this at `http://gcc.gnu.org/'. Note that
`gcc' 2.8.1 does not work reliably on SPARC.

The recommended `configure' line when using `gcc' 2.95.2 is:

     CC=gcc CFLAGS="-O3" \
     CXX=gcc CXXFLAGS="-O3 -felide-constructors -fno-exceptions -fno-rtti" \
     ./configure --prefix=/usr/local/mysql --with-low-memory \
         --enable-assembler

If you have an UltraSPARC system, you can get 4% better performance by
adding `-mcpu=v8 -Wa,-xarch=v8plusa' to the `CFLAGS' and `CXXFLAGS'
environment variables.

If you have Sun's Forte 5.0 (or newer) compiler, you can run
`configure' like this:

     CC=cc CFLAGS="-Xa -fast -native -xstrconst -mt" \
     CXX=CC CXXFLAGS="-noex -mt" \
     ./configure --prefix=/usr/local/mysql --enable-assembler

To create a 64-bit binary with Sun's Forte compiler, use the following
configuration options:

     CC=cc CFLAGS="-Xa -fast -native -xstrconst -mt -xarch=v9" \
     CXX=CC CXXFLAGS="-noex -mt -xarch=v9" ASFLAGS="-xarch=v9" \
     ./configure --prefix=/usr/local/mysql --enable-assembler

To create a 64-bit Solaris binary using `gcc', add `-m64' to `CFLAGS'
and `CXXFLAGS' and remove `--enable-assembler' from the `configure'
line.

In the MySQL benchmarks, we obtained a 4% speed increase on UltraSPARC
when using Forte 5.0 in 32-bit mode, as compared to using `gcc' 3.2
with the `-mcpu' flag.

If you create a 64-bit *Note `mysqld': mysqld. binary, it is 4% slower
than the 32-bit binary, but can handle more threads and memory.

When using Solaris 10 for x86_64, you should mount any file systems on
which you intend to store `InnoDB' files with the `forcedirectio'
option. (By default mounting is done without this option.) Failing to
do so will cause a significant drop in performance when using the
`InnoDB' storage engine on this platform.

If you get a problem with `fdatasync' or `sched_yield', you can fix
this by adding `LIBS=-lrt' to the `configure' line

For compilers older than WorkShop 5.3, you might have to edit the
`configure' script. Change this line:

     #if !defined(__STDC__) || __STDC__ != 1

To this:

     #if !defined(__STDC__)

If you turn on `__STDC__' with the `-Xc' option, the Sun compiler can't
compile with the Solaris `pthread.h' header file. This is a Sun bug
(broken compiler or broken include file).

If *Note `mysqld': mysqld. issues the following error message when you
run it, you have tried to compile MySQL with the Sun compiler without
enabling the `-mt' multi-thread option:

     libc internal error: _rmutex_unlock: rmutex not held

Add `-mt' to `CFLAGS' and `CXXFLAGS' and recompile.

If you are using the SFW version of `gcc' (which comes with Solaris 8),
you must add `/opt/sfw/lib' to the environment variable
`LD_LIBRARY_PATH' before running `configure'.

If you are using the `gcc' available from `sunfreeware.com', you may
have many problems.  To avoid this, you should recompile `gcc' and GNU
`binutils' on the machine where you are running them.

If you get the following error when compiling MySQL with `gcc', it
means that your `gcc' is not configured for your version of Solaris:

     shell> gcc -O3 -g -O2 -DDBUG_OFF  -o thr_alarm ...
     ./thr_alarm.c: In function `signal_hand':
     ./thr_alarm.c:556: too many arguments to function `sigwait'

The proper thing to do in this case is to get the newest version of
`gcc' and compile it with your current `gcc' compiler. At least for
Solaris 2.5, almost all binary versions of `gcc' have old, unusable
include files that break all programs that use threads, and possibly
other programs as well.

Solaris does not provide static versions of all system libraries
(`libpthreads' and `libdl'), so you cannot compile MySQL with
`--static'. If you try to do so, you get one of the following errors:

     ld: fatal: library -ldl: not found
     undefined reference to `dlopen'
     cannot find -lrt

If you link your own MySQL client programs, you may see the following
error at runtime:

     ld.so.1: fatal: libmysqlclient.so.#:
     open failed: No such file or directory

This problem can be avoided by one of the following methods:

   * Link clients with the `-Wl,r/full/path/to/libmysqlclient.so' flag
     rather than with `-Lpath').

   * Copy `libmysqclient.so' to `/usr/lib'.

   * Add the path name of the directory where `libmysqlclient.so' is
     located to the `LD_RUN_PATH' environment variable before running
     your client.

If you have problems with `configure' trying to link with `-lz' when
you do not have `zlib' installed, you have two options:

   * If you want to be able to use the compressed communication
     protocol, you need to get and install `zlib' from `ftp.gnu.org'.

   * Run `configure' with the `--with-named-z-libs=no' option when
     building MySQL.

If you are using `gcc' and have problems with loading user-defined
functions (UDFs) into MySQL, try adding `-lgcc' to the link line for
the UDF.

If you would like MySQL to start automatically, you can copy
`support-files/mysql.server' to `/etc/init.d' and create a symbolic
link to it named `/etc/rc3.d/S99mysql.server'.

If too many processes try to connect very rapidly to *Note `mysqld':
mysqld, you should see this error in the MySQL log:

     Error in accept: Protocol error

You might try starting the server with the `--back_log=50' option as a
workaround for this. (Use `-O back_log=50' before MySQL 4.)

To configure the generation of core files on Solaris you should use the
`coreadm' command. Because of the security implications of generating a
core on a `setuid()' application, by default, Solaris does not support
core files on `setuid()' programs. However, you can modify this
behavior using `coreadm'. If you enable `setuid()' core files for the
current user, they will be generated using the mode 600 and owned by the
superuser.


File: manual.info,  Node: solaris-2-7,  Next: solaris-x86,  Prev: solaris,  Up: solaris

3.20.3.1 Solaris 2.7/2.8 Notes
..............................

Normally, you can use a Solaris 2.6 binary on Solaris 2.7 and 2.8. Most
of the Solaris 2.6 issues also apply for Solaris 2.7 and 2.8.

MySQL should be able to detect new versions of Solaris automatically
and enable workarounds for the following problems.

Solaris 2.7 / 2.8 has some bugs in the include files. You may see the
following error when you use `gcc':

     /usr/include/widec.h:42: warning: `getwc' redefined
     /usr/include/wchar.h:326: warning: this is the location of the previous
     definition

If this occurs, you can fix the problem by copying
`/usr/include/widec.h' to `.../lib/gcc-lib/os/gcc-version/include' and
changing line 41 from this:

     #if     !defined(lint) && !defined(__lint)

To this:

     #if     !defined(lint) && !defined(__lint) && !defined(getwc)

Alternatively, you can edit `/usr/include/widec.h' directly. Either
way, after you make the fix, you should remove `config.cache' and run
`configure' again.

If you get the following errors when you run `make', it is because
`configure' didn't detect the `curses.h' file (probably because of the
error in `/usr/include/widec.h'):

     In file included from mysql.cc:50:
     /usr/include/term.h:1060: syntax error before `,'
     /usr/include/term.h:1081: syntax error before `;'

The solution to this problem is to do one of the following:

  1. Configure with `CFLAGS=-DHAVE_CURSES_H CXXFLAGS=-DHAVE_CURSES_H
     ./configure'.

  2. Edit `/usr/include/widec.h' as indicated in the preceding
     discussion and re-run `configure'.

  3. Remove the `#define HAVE_TERM' line from the `config.h' file and
     run `make' again.

If your linker cannot find `-lz' when linking client programs, the
problem is probably that your `libz.so' file is installed in
`/usr/local/lib'. You can fix this problem by one of the following
methods:

   * Add `/usr/local/lib' to `LD_LIBRARY_PATH'.

   * Add a link to `libz.so' from `/lib'.

   * If you are using Solaris 8, you can install the optional `zlib'
     from your Solaris 8 CD distribution.

   * Run `configure' with the `--with-named-z-libs=no' option when
     building MySQL.


File: manual.info,  Node: solaris-x86,  Prev: solaris-2-7,  Up: solaris

3.20.3.2 Solaris x86 Notes
..........................

On Solaris 8 on x86, *Note `mysqld': mysqld. dumps core if you remove
the debug symbols using `strip'.

If you are using `gcc' on Solaris x86 and you experience problems with
core dumps under load, you should use the following `configure' command:

     CC=gcc CFLAGS="-O3 -fomit-frame-pointer -DHAVE_CURSES_H" \
     CXX=gcc \
     CXXFLAGS="-O3 -fomit-frame-pointer -felide-constructors \
         -fno-exceptions -fno-rtti -DHAVE_CURSES_H" \
     ./configure --prefix=/usr/local/mysql

This avoids problems with the `libstdc++' library and with C++
exceptions.

If this doesn't help, you should compile a debug version and run it
with a trace file or under `gdb'. See MySQL Internals: Porting
(http://forge.mysql.com/wiki/MySQL_Internals_Porting).


File: manual.info,  Node: bsd-notes,  Next: other-unix-notes,  Prev: solaris,  Up: operating-system-specific-notes

3.20.4 BSD Notes
----------------

* Menu:

* freebsd::                      FreeBSD Notes
* netbsd::                       NetBSD Notes
* openbsd::                      OpenBSD 2.5 Notes
* bsdi::                         BSD/OS Version 2.x Notes
* bsdi3::                        BSD/OS Version 3.x Notes
* bsdi4::                        BSD/OS Version 4.x Notes

This section provides information about using MySQL on variants of BSD
Unix.


File: manual.info,  Node: freebsd,  Next: netbsd,  Prev: bsd-notes,  Up: bsd-notes

3.20.4.1 FreeBSD Notes
......................

FreeBSD 4.x or newer is recommended for running MySQL, because the
thread package is much more integrated. To get a secure and stable
system, you should use only FreeBSD kernels that are marked `-RELEASE'.

The easiest (and preferred) way to install MySQL is to use the *Note
`mysql-server': mysql-server. and `mysql-client' ports available at
`http://www.freebsd.org/'. Using these ports gives you the following
benefits:

   * A working MySQL with all optimizations enabled that are known to
     work on your version of FreeBSD.

   * Automatic configuration and build.

   * Startup scripts installed in `/usr/local/etc/rc.d'.

   * The ability to use `pkg_info -L' to see which files are installed.

   * The ability to use `pkg_delete' to remove MySQL if you no longer
     want it on your machine.

It is recommended you use MIT-pthreads on FreeBSD 2.x, and native
threads on FreeBSD 3 and up. It is possible to run with native threads
on some late 2.2.x versions, but you may encounter problems shutting
down *Note `mysqld': mysqld.

Unfortunately, certain function calls on FreeBSD are not yet fully
thread-safe. Most notably, this includes the `gethostbyname()'
function, which is used by MySQL to convert host names into IP
addresses. Under certain circumstances, the *Note `mysqld': mysqld.
process suddenly causes 100% CPU load and is unresponsive. If you
encounter this problem, try to start MySQL using the
`--skip-name-resolve' option.

Alternatively, you can link MySQL on FreeBSD 4.x against the
LinuxThreads library, which avoids a few of the problems that the
native FreeBSD thread implementation has. For a very good comparison of
LinuxThreads versus native threads, see Jeremy Zawodny's article
`FreeBSD or Linux for your MySQL Server?' at
`http://jeremy.zawodny.com/blog/archives/000697.html'.

Known problem when using LinuxThreads on FreeBSD is:

   * The connection times (`wait_timeout', `interactive_timeout' and
     `net_read_timeout') values are not honored. The symptom is that
     persistent connections can hang for a very long time without
     getting closed down and that a 'kill' for a thread will not take
     affect until the thread does it a new command

     This is probably a signal handling problem in the thread library
     where the signal doesn't break a pending read.  This is supposed
     to be fixed in FreeBSD 5.0

The MySQL build process requires GNU make (`gmake') to work. If GNU
`make' is not available, you must install it first before compiling
MySQL.

The recommended way to compile and install MySQL on FreeBSD with `gcc'
(2.95.2 and up) is:

     CC=gcc CFLAGS="-O2 -fno-strength-reduce" \
         CXX=gcc CXXFLAGS="-O2 -fno-rtti -fno-exceptions \
         -felide-constructors -fno-strength-reduce" \
         ./configure --prefix=/usr/local/mysql --enable-assembler
     gmake
     gmake install
     cd /usr/local/mysql
     bin/mysql_install_db --user=mysql
     bin/mysqld_safe &

Be sure that your name resolver setup is correct. Otherwise, you may
experience resolver delays or failures when connecting to *Note
`mysqld': mysqld. Also make sure that the `localhost' entry in the
`/etc/hosts' file is correct. The file should start with a line similar
to this:

     127.0.0.1       localhost localhost.your.domain

FreeBSD is known to have a very low default file handle limit.  See
*Note not-enough-file-handles::. Start the server by using the
`--open-files-limit' option for *Note `mysqld_safe': mysqld-safe, or
raise the limits for the *Note `mysqld': mysqld. user in
`/etc/login.conf' and rebuild it with `cap_mkdb /etc/login.conf'. Also
be sure that you set the appropriate class for this user in the password
file if you are not using the default (use `chpass mysqld-user-name').
See *Note mysqld-safe::.

FreeBSD limits the size of a process to 512MB, even if you have much
more RAM available on the system. So you may get an error such as this:

     Out of memory (Needed 16391 bytes)

In current versions of FreeBSD (at least 4.x and greater), you may
increase this limit by adding the following entries to the
`/boot/loader.conf' file and rebooting the machine (these are not
settings that can be changed at run time with the `sysctl' command):

     kern.maxdsiz="1073741824" # 1GB
     kern.dfldsiz="1073741824" # 1GB
     kern.maxssiz="134217728" # 128MB

For older versions of FreeBSD, you must recompile your kernel to change
the maximum data segment size for a process. In this case, you should
look at the `MAXDSIZ' option in the `LINT' config file for more
information.

If you get problems with the current date in MySQL, setting the `TZ'
variable should help. See *Note environment-variables::.


File: manual.info,  Node: netbsd,  Next: openbsd,  Prev: freebsd,  Up: bsd-notes

3.20.4.2 NetBSD Notes
.....................

To compile on NetBSD, you need GNU `make'.  Otherwise, the build
process fails when `make' tries to run `lint' on C++ files.


File: manual.info,  Node: openbsd,  Next: bsdi,  Prev: netbsd,  Up: bsd-notes

3.20.4.3 OpenBSD 2.5 Notes
..........................

On OpenBSD 2.5, you can compile MySQL with native threads with the
following options:

     CFLAGS=-pthread CXXFLAGS=-pthread ./configure --with-mit-threads=no


File: manual.info,  Node: bsdi,  Next: bsdi3,  Prev: openbsd,  Up: bsd-notes

3.20.4.4 BSD/OS Version 2.x Notes
.................................

If you get the following error when compiling MySQL, your `ulimit'
value for virtual memory is too low:

     item_func.h: In method
     `Item_func_ge::Item_func_ge(const Item_func_ge &)':
     item_func.h:28: virtual memory exhausted
     make[2]: *** [item_func.o] Error 1

Try using `ulimit -v 80000' and run `make' again. If this doesn't work
and you are using `bash', try switching to `csh' or `sh'; some BSDI
users have reported problems with `bash' and `ulimit'.

If you are using `gcc', you may also use have to use the
`--with-low-memory' flag for `configure' to be able to compile
`sql_yacc.cc'.

If you get problems with the current date in MySQL, setting the `TZ'
variable should help. See *Note environment-variables::.


File: manual.info,  Node: bsdi3,  Next: bsdi4,  Prev: bsdi,  Up: bsd-notes

3.20.4.5 BSD/OS Version 3.x Notes
.................................

Upgrade to BSD/OS 3.1. If that is not possible, install BSDIpatch
M300-038.

Use the following command when configuring MySQL:

     env CXX=shlicc++ CC=shlicc2 \
     ./configure \
         --prefix=/usr/local/mysql \
         --localstatedir=/var/mysql \
         --without-perl \
         --with-unix-socket-path=/var/mysql/mysql.sock

The following is also known to work:

     env CC=gcc CXX=gcc CXXFLAGS=-O3 \
     ./configure \
         --prefix=/usr/local/mysql \
         --with-unix-socket-path=/var/mysql/mysql.sock

You can change the directory locations if you wish, or just use the
defaults by not specifying any locations.

If you have problems with performance under heavy load, try using the
`--skip-thread-priority' option to *Note `mysqld': mysqld. This runs
all threads with the same priority. On BSDI 3.1, this gives better
performance, at least until BSDI fixes its thread scheduler.

If you get the error `virtual memory exhausted' while compiling, you
should try using `ulimit -v 80000' and running `make' again. If this
doesn't work and you are using `bash', try switching to `csh' or `sh';
some BSDI users have reported problems with `bash' and `ulimit'.


File: manual.info,  Node: bsdi4,  Prev: bsdi3,  Up: bsd-notes

3.20.4.6 BSD/OS Version 4.x Notes
.................................

BSDI 4.x has some thread-related bugs. If you want to use MySQL on
this, you should install all thread-related patches.  At least M400-023
should be installed.

On some BSDI 4.x systems, you may get problems with shared libraries.
The symptom is that you can't execute any client programs, for example,
*Note `mysqladmin': mysqladmin. In this case, you need to reconfigure
not to use shared libraries with the `--disable-shared' option to
configure.

Some customers have had problems on BSDI 4.0.1 that the *Note `mysqld':
mysqld. binary after a while can't open tables. This occurs because
some library/system-related bug causes *Note `mysqld': mysqld. to
change current directory without having asked for that to happen.

The fix is to either upgrade MySQL to at least version 3.23.34 or,
after running `configure', remove the line `#define HAVE_REALPATH' from
`config.h' before running `make'.

Note that this means that you can't symbolically link a database
directories to another database directory or symbolic link a table to
another database on BSDI. (Making a symbolic link to another disk is
okay).


File: manual.info,  Node: other-unix-notes,  Next: os-2,  Prev: bsd-notes,  Up: operating-system-specific-notes

3.20.5 Other Unix Notes
-----------------------

* Menu:

* hp-ux-10-20::                  HP-UX Version 10.20 Notes
* hp-ux-11-x::                   HP-UX Version 11.x Notes
* ibm-aix::                      IBM-AIX notes
* sunos::                        SunOS 4 Notes
* alpha-dec-unix::               Alpha-DEC-UNIX Notes (Tru64)
* alpha-dec-osf1::               Alpha-DEC-OSF/1 Notes
* sgi-irix::                     SGI Irix Notes
* sco::                          SCO UNIX and OpenServer 5.0.x Notes
* sco-openserver::               SCO OpenServer 6.0.x Notes
* sco-unixware::                 SCO UnixWare 7.1.x and OpenUNIX 8.0.0 Notes


File: manual.info,  Node: hp-ux-10-20,  Next: hp-ux-11-x,  Prev: other-unix-notes,  Up: other-unix-notes

3.20.5.1 HP-UX Version 10.20 Notes
..................................

If you install MySQL using a binary tarball distribution on HP-UX, you
may run into trouble even before you get the MySQL distribution
unpacked, as the HP-UX `tar' cannot handle long file names. This means
that you may see errors when you try to unpack MySQL.

If this occurs, you must use GNU `tar' (`gtar') to unpack the
distribution.

There are a couple of small problems when compiling MySQL on HP-UX. Use
`gcc' instead of the HP-UX native compiler, because `gcc' produces
better code.

Use `gcc' 2.95 on HP-UX. Do not use high optimization flags (such as
`-O6') because they may not be safe on HP-UX.

The following `configure' line should work with `gcc' 2.95:

     CFLAGS="-I/opt/dce/include -fpic" \
     CXXFLAGS="-I/opt/dce/include -felide-constructors -fno-exceptions \
     -fno-rtti" \
     CXX=gcc \
     ./configure --with-pthread \
         --with-named-thread-libs='-ldce' \
         --prefix=/usr/local/mysql --disable-shared

The following `configure' line should work with `gcc' 3.1:

     CFLAGS="-DHPUX -I/opt/dce/include -O3 -fPIC" CXX=gcc \
     CXXFLAGS="-DHPUX -I/opt/dce/include -felide-constructors \
         -fno-exceptions -fno-rtti -O3 -fPIC" \
     ./configure --prefix=/usr/local/mysql \
         --with-extra-charsets=complex --enable-thread-safe-client \
         --enable-local-infile  --with-pthread \
         --with-named-thread-libs=-ldce --with-lib-ccflags=-fPIC
         --disable-shared


File: manual.info,  Node: hp-ux-11-x,  Next: ibm-aix,  Prev: hp-ux-10-20,  Up: other-unix-notes

3.20.5.2 HP-UX Version 11.x Notes
.................................

If you install MySQL using a binary tarball distribution on HP-UX, you
may run into trouble even before you get the MySQL distribution
unpacked, as the HP-UX `tar' cannot handle long file names. This means
that you may see errors when you try to unpack MySQL.

If this occurs, you must use GNU `tar' (`gtar') to unpack the
distribution.

Because of some critical bugs in the standard HP-UX libraries, you
should install the following patches before trying to run MySQL on
HP-UX 11.0:

     PHKL_22840 Streams cumulative
     PHNE_22397 ARPA cumulative

This solves the problem of getting `EWOULDBLOCK' from `recv()' and
`EBADF' from `accept()' in threaded applications.

If you are using `gcc' 2.95.1 on an unpatched HP-UX 11.x system, you
may get the following error:

     In file included from /usr/include/unistd.h:11,
                      from ../include/global.h:125,
                      from mysql_priv.h:15,
                      from item.cc:19:
     /usr/include/sys/unistd.h:184: declaration of C function ...
     /usr/include/sys/pthread.h:440: previous declaration ...
     In file included from item.h:306,
                      from mysql_priv.h:158,
                      from item.cc:19:

The problem is that HP-UX does not define `pthreads_atfork()'
consistently. It has conflicting prototypes in
`/usr/include/sys/unistd.h':184 and `/usr/include/sys/pthread.h':440.

One solution is to copy `/usr/include/sys/unistd.h' into
`mysql/include' and edit `unistd.h' and change it to match the
definition in `pthread.h'. Look for this line:

     extern int pthread_atfork(void (*prepare)(), void (*parent)(),
                                               void (*child)());

Change it to look like this:

     extern int pthread_atfork(void (*prepare)(void), void (*parent)(void),
                                               void (*child)(void));

After making the change, the following `configure' line should work:

     CFLAGS="-fomit-frame-pointer -O3 -fpic" CXX=gcc \
     CXXFLAGS="-felide-constructors -fno-exceptions -fno-rtti -O3" \
     ./configure --prefix=/usr/local/mysql --disable-shared

If you are using HP-UX compiler, you can use the following command
(which has been tested with `cc' B.11.11.04):

     CC=cc CXX=aCC CFLAGS=+DD64 CXXFLAGS=+DD64 ./configure \
         --with-extra-character-set=complex

You can ignore any errors of the following type:

     aCC: warning 901: unknown option: `-3': use +help for online
     documentation

If you get the following error from `configure', verify that you do not
have the path to the K&R compiler before the path to the HP-UX C and
C++ compiler:

     checking for cc option to accept ANSI C... no
     configure: error: MySQL requires an ANSI C compiler (and a C++ compiler).
     Try gcc. See the Installation chapter in the Reference Manual.

Another reason for not being able to compile is that you didn't define
the `+DD64' flags as just described.

Another possibility for HP-UX 11 is to use the MySQL binaries provided
at `http://dev.mysql.com/downloads/', which we have built and tested
ourselves. We have also received reports that the HP-UX 10.20 binaries
supplied by MySQL can be run successfully on HP-UX 11. If you encounter
problems, you should be sure to check your HP-UX patch level.


File: manual.info,  Node: ibm-aix,  Next: sunos,  Prev: hp-ux-11-x,  Up: other-unix-notes

3.20.5.3 IBM-AIX notes
......................

Automatic detection of `xlC' is missing from Autoconf, so a number of
variables need to be set before running `configure'. The following
example uses the IBM compiler:

     export CC="xlc_r -ma -O3 -qstrict -qoptimize=3 -qmaxmem=8192 "
     export CXX="xlC_r -ma -O3 -qstrict -qoptimize=3 -qmaxmem=8192"
     export CFLAGS="-I /usr/local/include"
     export LDFLAGS="-L /usr/local/lib"
     export CPPFLAGS=$CFLAGS
     export CXXFLAGS=$CFLAGS

     ./configure --prefix=/usr/local \
                     --localstatedir=/var/mysql \
                     --sbindir='/usr/local/bin' \
                     --libexecdir='/usr/local/bin' \
                     --enable-thread-safe-client \
                     --enable-large-files

The preceding options are used to compile the MySQL distribution that
can be found at `http://www-frec.bull.com/'.

If you change the `-O3' to `-O2' in the preceding `configure' line, you
must also remove the `-qstrict' option. This is a limitation in the IBM
C compiler.

If you are using `gcc' to compile MySQL, you _must_ use the
`-fno-exceptions' flag, because the exception handling in `gcc' is not
thread-safe! There are also some known problems with IBM's assembler
that may cause it to generate bad code when used with `gcc'.

Use the following `configure' line with `gcc' 2.95 on AIX:

     CC="gcc -pipe -mcpu=power -Wa,-many" \
     CXX="gcc -pipe -mcpu=power -Wa,-many" \
     CXXFLAGS="-felide-constructors -fno-exceptions -fno-rtti" \
     ./configure --prefix=/usr/local/mysql --with-low-memory

The `-Wa,-many' option is necessary for the compile to be successful.
IBM is aware of this problem but is in no hurry to fix it because of
the workaround that is available. We do not know if the
`-fno-exceptions' is required with `gcc' 2.95, but because MySQL
doesn't use exceptions and the option generates faster code, you should
always use it with `gcc'.

If you get a problem with assembler code, try changing the `-mcpu=XXX'
option to match your CPU. Typically `power2', `power', or `powerpc' may
need to be used. Alternatively, you might need to use `604' or `604e'.
We are not positive but suspect that `power' would likely be safe most
of the time, even on a power2 machine.

If you do not know what your CPU is, execute a `uname -m' command. It
produces a string that looks like `000514676700', with a format of
`xxyyyyyymmss' where `xx' and `ss' are always `00', `yyyyyy' is a
unique system ID and `mm' is the ID of the CPU Planar. A chart of these
values can be found at
`http://www16.boulder.ibm.com/pseries/en_US/cmds/aixcmds5/uname.htm'.

This gives you a machine type and a machine model you can use to
determine what type of CPU you have.

If you have problems with threads on AIX 5.3, you should upgrade AIX
5.3 to technology level 7 (5300-07).

If you have problems with signals (MySQL dies unexpectedly under high
load), you may have found an OS bug with threads and signals. In this
case, you can tell MySQL not to use signals by configuring as follows:

     CFLAGS=-DDONT_USE_THR_ALARM CXX=gcc \
     CXXFLAGS="-felide-constructors -fno-exceptions -fno-rtti \
     -DDONT_USE_THR_ALARM" \
     ./configure --prefix=/usr/local/mysql --with-debug \
         --with-low-memory

This doesn't affect the performance of MySQL, but has the side effect
that you can't kill clients that are `sleeping' on a connection with
*Note `mysqladmin kill': mysqladmin. or *Note `mysqladmin shutdown':
mysqladmin. Instead, the client dies when it issues its next command.

On some versions of AIX, linking with `libbind.a' makes
`getservbyname()' dump core. This is an AIX bug and should be reported
to IBM.

For AIX 4.2.1 and `gcc', you have to make the following changes.

After configuring, edit `config.h' and `include/my_config.h' and change
the line that says this:

     #define HAVE_SNPRINTF 1

to this:

     #undef HAVE_SNPRINTF

And finally, in `mysqld.cc', you need to add a prototype for
`initgroups()'.

     #ifdef _AIX41
     extern "C" int initgroups(const char *,int);
     #endif

For 32-bit binaries, if you need to allocate a lot of memory to the
*Note `mysqld': mysqld. process, it is not enough to just use `ulimit
-d unlimited'. You may also have to modify *Note `mysqld_safe':
mysqld-safe. to add a line something like this:

     export LDR_CNTRL='MAXDATA=0x80000000'

You can find more information about using a lot of memory at
`http://publib16.boulder.ibm.com/pseries/en_US/aixprggd/genprogc/lrg_prg_support.htm'.

Users of AIX 4.3 should use `gmake' instead of the `make' utility
included with AIX.

As of AIX 4.1, the C compiler has been unbundled from AIX as a separate
product. `gcc' 3.3.2 can be obtained here:
`ftp://ftp.software.ibm.com/aix/freeSoftware/aixtoolbox/RPMS/ppc/gcc/'

The steps for compiling MySQL on AIX with `gcc' 3.3.2 are similar to
those for using `gcc' 2.95 (in particular, the need to edit `config.h'
and `my_config.h' after running `configure'). However, before running
`configure', you should also patch the `curses.h' file as follows:

     /opt/freeware/lib/gcc-lib/powerpc-ibm-aix5.2.0.0/3.3.2/include/curses.h.ORIG
            Mon Dec 26 02:17:28 2005
     --- /opt/freeware/lib/gcc-lib/powerpc-ibm-aix5.2.0.0/3.3.2/include/curses.h
     Mon Dec 26 02:40:13 2005
     ***************
     *** 2023,2029 ****

       #endif /* _AIX32_CURSES */
     ! #if defined(__USE_FIXED_PROTOTYPES__) || defined(__cplusplus) || defined
     (__STRICT_ANSI__)
       extern int delwin (WINDOW *);
       extern int endwin (void);
       extern int getcurx (WINDOW *);
     --- 2023,2029 ----

       #endif /* _AIX32_CURSES */
     ! #if 0 && (defined(__USE_FIXED_PROTOTYPES__) || defined(__cplusplus)
     || defined
     (__STRICT_ANSI__))
       extern int delwin (WINDOW *);
       extern int endwin (void);
       extern int getcurx (WINDOW *);


File: manual.info,  Node: sunos,  Next: alpha-dec-unix,  Prev: ibm-aix,  Up: other-unix-notes

3.20.5.4 SunOS 4 Notes
......................

On SunOS 4, MIT-pthreads is needed to compile MySQL. This in turn means
you need GNU `make'.

Some SunOS 4 systems have problems with dynamic libraries and
`libtool'. You can use the following `configure' line to avoid this
problem:

     ./configure --disable-shared --with-mysqld-ldflags=-all-static

When compiling `readline', you may get warnings about duplicate
defines. These can be ignored.

When compiling *Note `mysqld': mysqld, there are some `implicit
declaration of function' warnings.  These can be ignored.


File: manual.info,  Node: alpha-dec-unix,  Next: alpha-dec-osf1,  Prev: sunos,  Up: other-unix-notes

3.20.5.5 Alpha-DEC-UNIX Notes (Tru64)
.....................................

If you are using `egcs' 1.1.2 on Digital Unix, you should upgrade to
`gcc' 2.95.2, because `egcs' on DEC has some serious bugs!

When compiling threaded programs under Digital Unix, the documentation
recommends using the `-pthread' option for `cc' and `cxx' and the
`-lmach -lexc' libraries (in addition to `-lpthread'). You should run
`configure' something like this:

     CC="cc -pthread" CXX="cxx -pthread -O" \
     ./configure --with-named-thread-libs="-lpthread -lmach -lexc -lc"

When compiling *Note `mysqld': mysqld, you may see a couple of warnings
like this:

     mysqld.cc: In function void handle_connections()':
     mysqld.cc:626: passing long unsigned int *' as argument 3 of
     accept(int,sockadddr *, int *)'

You can safely ignore these warnings. They occur because `configure'
can detect only errors, not warnings.

If you start the server directly from the command line, you may have
problems with it dying when you log out. (When you log out, your
outstanding processes receive a `SIGHUP' signal.) If so, try starting
the server like this:

     nohup mysqld [OPTIONS] &

`nohup' causes the command following it to ignore any `SIGHUP' signal
sent from the terminal. Alternatively, start the server by running
*Note `mysqld_safe': mysqld-safe, which invokes *Note `mysqld': mysqld.
using `nohup' for you. See *Note mysqld-safe::.

If you get a problem when compiling `mysys/get_opt.c', just remove the
`#define _NO_PROTO' line from the start of that file.

If you are using Compaq's CC compiler, the following `configure' line
should work:

     CC="cc -pthread"
     CFLAGS="-O4 -ansi_alias -ansi_args -fast -inline speed \
             -speculate all -arch host"
     CXX="cxx -pthread"
     CXXFLAGS="-O4 -ansi_alias -ansi_args -fast -inline speed \
               -speculate all -arch host -noexceptions -nortti"
     export CC CFLAGS CXX CXXFLAGS
     ./configure \
         --prefix=/usr/local/mysql \
         --with-low-memory \
         --enable-large-files \
         --enable-shared=yes \
         --with-named-thread-libs="-lpthread -lmach -lexc -lc"
     gnumake

If you get a problem with `libtool' when compiling with shared
libraries as just shown, when linking *Note `mysql': mysql, you should
be able to get around this by issuing these commands:

     cd mysql
     /bin/sh ../libtool --mode=link cxx -pthread  -O3 -DDBUG_OFF \
         -O4 -ansi_alias -ansi_args -fast -inline speed \
         -speculate all \ -arch host  -DUNDEF_HAVE_GETHOSTBYNAME_R \
         -o mysql  mysql.o readline.o sql_string.o completion_hash.o \
         ../readline/libreadline.a -lcurses \
         ../libmysql/.libs/libmysqlclient.so  -lm
     cd ..
     gnumake
     gnumake install
     scripts/mysql_install_db


File: manual.info,  Node: alpha-dec-osf1,  Next: sgi-irix,  Prev: alpha-dec-unix,  Up: other-unix-notes

3.20.5.6 Alpha-DEC-OSF/1 Notes
..............................

If you have problems compiling and have DEC `CC' and `gcc' installed,
try running `configure' like this:

     CC=cc CFLAGS=-O CXX=gcc CXXFLAGS=-O3 \
     ./configure --prefix=/usr/local/mysql

If you get problems with the `c_asm.h' file, you can create and use a
'dummy' `c_asm.h' file with:

     touch include/c_asm.h
     CC=gcc CFLAGS=-I./include \
     CXX=gcc CXXFLAGS=-O3 \
     ./configure --prefix=/usr/local/mysql

Note that the following problems with the `ld' program can be fixed by
downloading the latest DEC (Compaq) patch kit from:
`http://ftp.support.compaq.com/public/unix/'.

On OSF/1 V4.0D and compiler "DEC C V5.6-071 on Digital Unix V4.0 (Rev.
878)," the compiler had some strange behavior (undefined `asm' symbols).
`/bin/ld' also appears to be broken (problems with `_exit undefined'
errors occurring while linking *Note `mysqld': mysqld.). On this
system, we have managed to compile MySQL with the following `configure'
line, after replacing `/bin/ld' with the version from OSF 4.0C:

     CC=gcc CXX=gcc CXXFLAGS=-O3 ./configure --prefix=/usr/local/mysql

With the Digital compiler "C++ V6.1-029," the following should work:

     CC=cc -pthread
     CFLAGS=-O4 -ansi_alias -ansi_args -fast -inline speed \
            -speculate all -arch host
     CXX=cxx -pthread
     CXXFLAGS=-O4 -ansi_alias -ansi_args -fast -inline speed \
              -speculate all -arch host -noexceptions -nortti
     export CC CFLAGS CXX CXXFLAGS
     ./configure --prefix=/usr/mysql/mysql \
                 --with-mysqld-ldflags=-all-static --disable-shared \
                 --with-named-thread-libs="-lmach -lexc -lc"

In some versions of OSF/1, the `alloca()' function is broken. Fix this
by removing the line in `config.h' that defines `'HAVE_ALLOCA''.

The `alloca()' function also may have an incorrect prototype in
`/usr/include/alloca.h'. This warning resulting from this can be
ignored.

`configure' uses the following thread libraries automatically:
`--with-named-thread-libs="-lpthread -lmach -lexc -lc"'.

When using `gcc', you can also try running `configure' like this:

     CFLAGS=-D_PTHREAD_USE_D4 CXX=gcc CXXFLAGS=-O3 ./configure ...

If you have problems with signals (MySQL dies unexpectedly under high
load), you may have found an OS bug with threads and signals. In this
case, you can tell MySQL not to use signals by configuring with:

     CFLAGS=-DDONT_USE_THR_ALARM \
     CXXFLAGS=-DDONT_USE_THR_ALARM \
     ./configure ...

This does not affect the performance of MySQL, but has the side effect
that you can't kill clients that are `sleeping' on a connection with
*Note `mysqladmin kill': mysqladmin. or *Note `mysqladmin shutdown':
mysqladmin. Instead, the client dies when it issues its next command.

With `gcc' 2.95.2, you may encounter the following compile error:

     sql_acl.cc:1456: Internal compiler error in `scan_region',
     at except.c:2566
     Please submit a full bug report.

To fix this, you should change to the `sql' directory and do a
cut-and-paste of the last `gcc' line, but change `-O3' to `-O0' (or add
`-O0' immediately after `gcc' if you do not have any `-O' option on
your compile line). After this is done, you can just change back to the
top-level directory and run `make' again.


File: manual.info,  Node: sgi-irix,  Next: sco,  Prev: alpha-dec-osf1,  Up: other-unix-notes

3.20.5.7 SGI Irix Notes
.......................

As of MySQL 5.0, we do not provide binaries for Irix any more.

If you are using Irix 6.5.3 or newer, *Note `mysqld': mysqld. is able
to create threads only if you run it as a user that has `CAP_SCHED_MGT'
privileges (such as `root') or give the *Note `mysqld': mysqld. server
this privilege with the following shell command:

     chcap "CAP_SCHED_MGT+epi" /opt/mysql/libexec/mysqld

You may have to undefine some symbols in `config.h' after running
`configure' and before compiling.

In some Irix implementations, the `alloca()' function is broken. If the
*Note `mysqld': mysqld. server dies on some *Note `SELECT': select.
statements, remove the lines from `config.h' that define `HAVE_ALLOC'
and `HAVE_ALLOCA_H'. If *Note `mysqladmin create': mysqladmin. doesn't
work, remove the line from `config.h' that defines `HAVE_READDIR_R'.
You may have to remove the `HAVE_TERM_H' line as well.

SGI recommends that you install all the patches on this page as a set:
`http://support.sgi.com/surfzone/patches/patchset/6.2_indigo.rps.html'

At the very minimum, you should install the latest kernel rollup, the
latest `rld' rollup, and the latest `libc' rollup.

You definitely need all the POSIX patches on this page, for pthreads
support:

`http://support.sgi.com/surfzone/patches/patchset/6.2_posix.rps.html'

If you get the something like the following error when compiling
`mysql.cc':

     "/usr/include/curses.h", line 82: error(1084):
     invalid combination of type

Type the following in the top-level directory of your MySQL source tree:

     extra/replace bool curses_bool < /usr/include/curses.h > include/curses.h
     make

There have also been reports of scheduling problems. If only one thread
is running, performance is slow. Avoid this by starting another client.
This may lead to a two-to-tenfold increase in execution speed
thereafter for the other thread.  This is a poorly understood problem
with Irix threads; you may have to improvise to find solutions until
this can be fixed.

If you are compiling with `gcc', you can use the following `configure'
command:

     CC=gcc CXX=gcc CXXFLAGS=-O3 \
     ./configure --prefix=/usr/local/mysql --enable-thread-safe-client \
         --with-named-thread-libs=-lpthread

On Irix 6.5.11 with native Irix C and C++ compilers ver.  7.3.1.2, the
following is reported to work

     CC=cc CXX=CC CFLAGS='-O3 -n32 -TARG:platform=IP22 -I/usr/local/include \
     -L/usr/local/lib' CXXFLAGS='-O3 -n32 -TARG:platform=IP22 \
     -I/usr/local/include -L/usr/local/lib' \
     ./configure --prefix=/usr/local/mysql --with-innodb --with-berkeley-db \
         --with-libwrap=/usr/local \
         --with-named-curses-libs=/usr/local/lib/libncurses.a


File: manual.info,  Node: sco,  Next: sco-openserver,  Prev: sgi-irix,  Up: other-unix-notes

3.20.5.8 SCO UNIX and OpenServer 5.0.x Notes
............................................

The current port is tested only on `sco3.2v5.0.5', `sco3.2v5.0.6', and
`sco3.2v5.0.7' systems. There has also been progress on a port to
`sco3.2v4.2'. Open Server 5.0.8 (Legend) has native threads and permits
files greater than 2GB. The current maximum file size is 2GB.

We have been able to compile MySQL with the following `configure'
command on OpenServer with `gcc' 2.95.3.

     CC=gcc CFLAGS="-D_FILE_OFFSET_BITS=64 -O3" \
     CXX=gcc CXXFLAGS="-D_FILE_OFFSET_BITS=64 -O3" \
     ./configure --prefix=/usr/local/mysql \
         --enable-thread-safe-client --with-innodb \
         --with-openssl --with-vio --with-extra-charsets=complex

`gcc' is available at
`ftp://ftp.sco.com/pub/openserver5/opensrc/gnutools-5.0.7Kj'.

This development system requires the OpenServer Execution Environment
Supplement oss646B on OpenServer 5.0.6 and oss656B and the OpenSource
libraries found in gwxlibs. All OpenSource tools are in the `opensrc'
directory. They are available at
`ftp://ftp.sco.com/pub/openserver5/opensrc/'.

Use the latest production release of MySQL.

SCO provides operating system patches at
`ftp://ftp.sco.com/pub/openserver5' for OpenServer 5.0.[0-6] and
`ftp://ftp.sco.com/pub/openserverv5/507' for OpenServer 5.0.7.

SCO provides information about security fixes at
`ftp://ftp.sco.com/pub/security/OpenServer' for OpenServer 5.0.x.

The maximum file size on an OpenServer 5.0.x system is 2GB.

The total memory which can be allocated for streams buffers, clists,
and lock records cannot exceed 60MB on OpenServer 5.0.x.

Streams buffers are allocated in units of 4096 byte pages, clists are
70 bytes each, and lock records are 64 bytes each, so:

     (NSTRPAGES * 4096) + (NCLIST * 70) + (MAX_FLCKREC * 64) <= 62914560

Follow this procedure to configure the Database Services option. If you
are unsure whether an application requires this, see the documentation
provided with the application.

  1. Log in as `root'.

  2. Enable the SUDS driver by editing the `/etc/conf/sdevice.d/suds'
     file. Change the `N' in the second field to a `Y'.

  3. Use `mkdev aio' or the Hardware/Kernel Manager to enable support
     for asynchronous I/O and relink the kernel. To enable users to
     lock down memory for use with this type of I/O, update the
     aiomemlock(F) file. This file should be updated to include the
     names of users that can use AIO and the maximum amounts of memory
     they can lock down.

  4. Many applications use setuid binaries so that you need to specify
     only a single user. See the documentation provided with the
     application to determine whether this is the case for your
     application.

After you complete this process, reboot the system to create a new
kernel incorporating these changes.

By default, the entries in `/etc/conf/cf.d/mtune' are set as follows:

     Value           Default         Min             Max
     -----           -------         ---             ---
     NBUF            0               24              450000
     NHBUF           0               32              524288
     NMPBUF          0               12              512
     MAX_INODE       0               100             64000
     MAX_FILE        0               100             64000
     CTBUFSIZE       128             0               256
     MAX_PROC        0               50              16000
     MAX_REGION      0               500             160000
     NCLIST          170             120             16640
     MAXUP           100             15              16000
     NOFILES         110             60              11000
     NHINODE         128             64              8192
     NAUTOUP         10              0               60
     NGROUPS         8               0               128
     BDFLUSHR        30              1               300
     MAX_FLCKREC     0               50              16000
     PUTBUFSZ        8000            2000            20000
     MAXSLICE        100             25              100
     ULIMIT          4194303         2048            4194303
     * Streams Parameters
     NSTREAM         64              1               32768
     NSTRPUSH        9               9               9
     NMUXLINK        192             1               4096
     STRMSGSZ        16384           4096            524288
     STRCTLSZ        1024            1024            1024
     STRMAXBLK       524288          4096            524288
     NSTRPAGES       500             0               8000
     STRSPLITFRAC    80              50              100
     NLOG            3               3               3
     NUMSP           64              1               256
     NUMTIM          16              1               8192
     NUMTRW          16              1               8192
     * Semaphore Parameters
     SEMMAP          10              10              8192
     SEMMNI          10              10              8192
     SEMMNS          60              60              8192
     SEMMNU          30              10              8192
     SEMMSL          25              25              150
     SEMOPM          10              10              1024
     SEMUME          10              10              25
     SEMVMX          32767           32767           32767
     SEMAEM          16384           16384           16384
     * Shared Memory Parameters
     SHMMAX          524288          131072          2147483647
     SHMMIN          1               1               1
     SHMMNI          100             100             2000
     FILE            0               100             64000
     NMOUNT          0               4               256
     NPROC           0               50              16000
     NREGION         0               500             160000

Set these values as follows:

   * `NOFILES' should be 4096 or 2048.

   * `MAXUP' should be 2048.

To make changes to the kernel, use the `idtune NAME PARAMETER' command.
`idtune' modifies the `/etc/conf/cf.d/stune' file for you. For example,
to change `SEMMS' to `200', execute this command as `root':

     # /etc/conf/bin/idtune SEMMNS 200

Then rebuild and reboot the kernel by issuing this command:

     # /etc/conf/bin/idbuild -B && init 6

To tune the system, the proper parameter values to use depend on the
number of users accessing the application or database and size the of
the database (that is, the used buffer pool).  The following kernel
parameters can be set with `idtune':

   * `SHMMAX' (recommended setting: 128MB) and `SHMSEG' (recommended
     setting: 15). These parameters have an influence on the MySQL
     database engine to create user buffer pools.

   * `NOFILES' and `MAXUP' should be set to at least 2048.

   * `MAXPROC' should be set to at least 3000/4000 (depends on number
     of users) or more.

   * The following formulas are recommended to calculate values for
     `SEMMSL', `SEMMNS', and `SEMMNU':

          SEMMSL = 13

     13 is what has been found to be the best for both Progress and
     MySQL.

          SEMMNS = SEMMSL * NUMBER OF DB SERVERS TO BE RUN ON THE SYSTEM

     Set `SEMMNS' to the value of `SEMMSL' multiplied by the number of
     database servers (maximum) that you are running on the system at
     one time.

          SEMMNU = SEMMNS

     Set the value of `SEMMNU' to equal the value of `SEMMNS'. You
     could probably set this to 75% of `SEMMNS', but this is a
     conservative estimate.

You need to at least install the SCO OpenServer Linker and Application
Development Libraries or the OpenServer Development System to use
`gcc'. You cannot use the GCC Dev system without installing one of
these.

You should get the FSU Pthreads package and install it first.  This can
be found at
`http://moss.csc.ncsu.edu/~mueller/ftp/pub/PART/pthreads.tar.gz'.  You
can also get a precompiled package from
`ftp://ftp.zenez.com/pub/zenez/prgms/FSU-threads-3.14.tar.gz'.

FSU Pthreads can be compiled with SCO Unix 4.2 with tcpip, or using
OpenServer 3.0 or Open Desktop 3.0 (OS 3.0 ODT 3.0) with the SCO
Development System installed using a good port of GCC 2.5.x. For ODT or
OS 3.0, you need a good port of GCC 2.5.x.  There are a lot of problems
without a good port. The port for this product requires the SCO Unix
Development system. Without it, you are missing the libraries and the
linker that is needed. You also need `SCO-3.2v4.2-includes.tar.gz'.
This file contains the changes to the SCO Development include files that
are needed to get MySQL to build. You need to replace the existing
system include files with these modified header files. They can be
obtained from
`ftp://ftp.zenez.com/pub/zenez/prgms/SCO-3.2v4.2-includes.tar.gz'.

To build FSU Pthreads on your system, all you should need to do is run
GNU `make'. The `Makefile' in FSU-threads-3.14.tar.gz is set up to make
FSU-threads.

You can run `./configure' in the `threads/src' directory and select the
SCO OpenServer option. This command copies `Makefile.SCO5' to
`Makefile'. Then run `make'.

To install in the default `/usr/include' directory, log in as `root',
and then `cd' to the `thread/src' directory and run `make install'.

Remember that you must use GNU `make' to build MySQL.

*Note*:

If you do not start *Note `mysqld_safe': mysqld-safe. as `root', you
should get only the default 110 open files per process. *Note `mysqld':
mysqld. writes a note about this in the log file.

With SCO 3.2V4.2, you should use FSU Pthreads version 3.14 or newer.
The following `configure' command should work:

     CFLAGS="-D_XOPEN_XPG4" CXX=gcc CXXFLAGS="-D_XOPEN_XPG4" \
     ./configure \
         --prefix=/usr/local/mysql \
         --with-named-thread-libs="-lgthreads -lsocket -lgen -lgthreads" \
         --with-named-curses-libs="-lcurses"

You may have problems with some include files. In this case, you can
find new SCO-specific include files at
`ftp://ftp.zenez.com/pub/zenez/prgms/SCO-3.2v4.2-includes.tar.gz'.

You should unpack this file in the `include' directory of your MySQL
source tree.

SCO development notes:

   * MySQL should automatically detect FSU Pthreads and link *Note
     `mysqld': mysqld. with `-lgthreads -lsocket -lgthreads'.

   * The SCO development libraries are re-entrant in FSU Pthreads. SCO
     claims that its library functions are re-entrant, so they must be
     re-entrant with FSU Pthreads.  FSU Pthreads on OpenServer tries to
     use the SCO scheme to make re-entrant libraries.

   * FSU Pthreads (at least the version at `ftp://ftp.zenez.com') comes
     linked with GNU `malloc'. If you encounter problems with memory
     usage, make sure that `gmalloc.o' is included in `libgthreads.a'
     and `libgthreads.so'.

   * In FSU Pthreads, the following system calls are pthreads-aware:
     `read()', `write()', `getmsg()', `connect()', `accept(),'
     `select()', and `wait()'.

   * The CSSA-2001-SCO.35.2 (the patch is listed in custom as
     erg711905-dscr_remap security patch (version 2.0.0)) breaks FSU
     threads and makes *Note `mysqld': mysqld.  unstable. You have to
     remove this one if you want to run *Note `mysqld': mysqld. on an
     OpenServer 5.0.6 machine.

   * If you use SCO OpenServer 5, you may need to recompile FSU
     pthreads with `-DDRAFT7' in `CFLAGS'. Otherwise, `InnoDB' may hang
     at a *Note `mysqld': mysqld. startup.

   * SCO provides operating system patches at
     `ftp://ftp.sco.com/pub/openserver5' for OpenServer 5.0.x.

   * SCO provides security fixes and `libsocket.so.2' at
     `ftp://ftp.sco.com/pub/security/OpenServer' and
     `ftp://ftp.sco.com/pub/security/sse' for OpenServer 5.0.x.

   * Pre-OSR506 security fixes. Also, the `telnetd' fix at
     `ftp://stage.caldera.com/pub/security/openserver/' or
     `ftp://stage.caldera.com/pub/security/openserver/CSSA-2001-SCO.10/'
     as both `libsocket.so.2' and `libresolv.so.1' with instructions for
     installing on pre-OSR506 systems.

     It is probably a good idea to install these patches before trying
     to compile/use MySQL.

Beginning with Legend/OpenServer 6.0.0, there are native threads and no
2GB file size limit.


File: manual.info,  Node: sco-openserver,  Next: sco-unixware,  Prev: sco,  Up: other-unix-notes

3.20.5.9 SCO OpenServer 6.0.x Notes
...................................

OpenServer 6 includes these key improvements:

   * Larger file support up to 1 TB

   * Multiprocessor support increased from 4 to 32 processors

   * Increased memory support up to 64GB

   * Extending the power of UnixWare into OpenServer 6

   * Dramatic performance improvement

OpenServer 6.0.0 commands are organized as follows:

   * `/bin' is for commands that behave exactly the same as on
     OpenServer 5.0.x.

   * `/u95/bin' is for commands that have better standards conformance,
     for example Large File System (LFS) support.

   * `/udk/bin' is for commands that behave the same as on UnixWare
     7.1.4. The default is for the LFS support.

The following is a guide to setting `PATH' on OpenServer 6. If the user
wants the traditional OpenServer 5.0.x then `PATH' should be `/bin'
first. If the user wants LFS support, the path should be
`/u95/bin:/bin'. If the user wants UnixWare 7 support first, the path
would be `/udk/bin:/u95/bin:/bin:'.

Use the latest production release of MySQL. Should you choose to use an
older release of MySQL on OpenServer 6.0.x, you must use a version of
MySQL at least as recent as 3.22.13 to get fixes for some portability
and OS problems.

MySQL distribution files with names of the following form are `tar'
archives of media are tar archives of media images suitable for
installation with the SCO Software Manager (`/etc/custom') on SCO
OpenServer 6:

     mysql-PRODUCT-5.0.95-sco-osr6-i686.VOLS.tar

A distribution where PRODUCT is `pro-cert' is the Commercially licensed
MySQL Pro Certified server. A distribution where PRODUCT is
`pro-gpl-cert' is the MySQL Pro Certified server licensed under the
terms of the General Public License (GPL).

Select whichever distribution you wish to install and, after download,
extract the `tar' archive into an empty directory. For example:

     shell> mkdir /tmp/mysql-pro
     shell> cd /tmp/mysql-pro
     shell> tar xf /tmp/mysql-pro-cert-5.0.95-sco-osr6-i686.VOLS.tar

Prior to installation, back up your data in accordance with the
procedures outlined in *Note upgrading::.

Remove any previously installed `pkgadd' version of MySQL:

     shell> pkginfo mysql 2>&1 > /dev/null && pkgrm mysql

Install MySQL Pro from media images using the SCO Software Manager:

     shell> /etc/custom -p SCO:MySQL -i -z /tmp/mysql-pro

Alternatively, the SCO Software Manager can be displayed graphically by
clicking the `Software Manager' icon on the desktop, selecting
`Software -> Install New', selecting the host, selecting `Media Images'
for the Media Device, and entering `/tmp/mysql-pro' as the Image
Directory.

After installation, run `mkdev mysql' as the `root' user to configure
your newly installed MySQL Pro Certified server.

*Note*:

The installation procedure for VOLS packages does not create the
`mysql' user and group that the package uses by default. You should
either create the `mysql' user and group, or else select a different
user and group using an option in `mkdev mysql'.

If you wish to configure your MySQL Pro server to interface with the
Apache Web server using PHP, download and install the PHP update from
SCO at `ftp://ftp.sco.com/pub/updates/OpenServer/SCOSA-2006.17/'.

We have been able to compile MySQL with the following `configure'
command on OpenServer 6.0.x:

     CC=cc CFLAGS="-D_FILE_OFFSET_BITS=64 -O3" \
     CXX=CC CXXFLAGS="-D_FILE_OFFSET_BITS=64 -O3" \
     ./configure --prefix=/usr/local/mysql \
         --enable-thread-safe-client --with-berkeley-db \
         --with-extra-charsets=complex \
         --build=i686-unknown-sysv5SCO_SV6.0.0

If you use `gcc', you must use `gcc' 2.95.3 or newer.

     CC=gcc CXX=g++ ... ./configure ...

The version of Berkeley DB that comes with either UnixWare 7.1.4 or
OpenServer 6.0.0 is not used when building MySQL.  MySQL instead uses
its own version of Berkeley DB. The `configure' command needs to build
both a static and a dynamic library in `SRC_DIRECTORY/bdb/build_unix/',
but it does not with MySQL's own `BDB' version. The workaround is as
follows.

  1. Configure as normal for MySQL.

  2. `cd bdb/build_unix/'

  3. `cp -p Makefile Makefile.sav'

  4. Use same options and run `../dist/configure'.

  5. Run `gmake'.

  6. `cp -p Makefile.sav Makefile'

  7. Change location to the top source directory and run `gmake'.

This enables both the shared and dynamic libraries to be made and work.

SCO provides OpenServer 6 operating system patches at
`ftp://ftp.sco.com/pub/openserver6'.

SCO provides information about security fixes at
`ftp://ftp.sco.com/pub/security/OpenServer'.

By default, the maximum file size on a OpenServer 6.0.0 system is 1TB.
Some operating system utilities have a limitation of 2GB. The maximum
possible file size on UnixWare 7 is 1TB with VXFS or HTFS.

OpenServer 6 can be configured for large file support (file sizes
greater than 2GB) by tuning the UNIX kernel.

By default, the entries in `/etc/conf/cf.d/mtune' are set as follows:

     Value           Default         Min             Max
     -----           -------         ---             ---
     SVMMLIM         0x9000000       0x1000000       0x7FFFFFFF
     HVMMLIM         0x9000000       0x1000000       0x7FFFFFFF

To make changes to the kernel, use the `idtune NAME PARAMETER' command.
`idtune' modifies the `/etc/conf/cf.d/stune' file for you. To set the
kernel values, execute the following commands as `root':

     # /etc/conf/bin/idtune SDATLIM 0x7FFFFFFF
     # /etc/conf/bin/idtune HDATLIM 0x7FFFFFFF
     # /etc/conf/bin/idtune SVMMLIM 0x7FFFFFFF
     # /etc/conf/bin/idtune HVMMLIM 0x7FFFFFFF
     # /etc/conf/bin/idtune SFNOLIM 2048
     # /etc/conf/bin/idtune HFNOLIM 2048

Then rebuild and reboot the kernel by issuing this command:

     # /etc/conf/bin/idbuild -B && init 6

To tune the system, the proper parameter values to use depend on the
number of users accessing the application or database and size the of
the database (that is, the used buffer pool).  The following kernel
parameters can be set with `idtune':

   * `SHMMAX' (recommended setting: 128MB) and `SHMSEG' (recommended
     setting: 15). These parameters have an influence on the MySQL
     database engine to create user buffer pools.

   * `SFNOLIM' and `HFNOLIM' should be at maximum 2048.

   * `NPROC' should be set to at least 3000/4000 (depends on number of
     users).

   * The following formulas are recommended to calculate values for
     `SEMMSL', `SEMMNS', and `SEMMNU':

          SEMMSL = 13

     13 is what has been found to be the best for both Progress and
     MySQL.

          SEMMNS = SEMMSL * NUMBER OF DB SERVERS TO BE RUN ON THE SYSTEM

     Set `SEMMNS' to the value of `SEMMSL' multiplied by the number of
     database servers (maximum) that you are running on the system at
     one time.

          SEMMNU = SEMMNS

     Set the value of `SEMMNU' to equal the value of `SEMMNS'. You
     could probably set this to 75% of `SEMMNS', but this is a
     conservative estimate.


File: manual.info,  Node: sco-unixware,  Prev: sco-openserver,  Up: other-unix-notes

3.20.5.10 SCO UnixWare 7.1.x and OpenUNIX 8.0.0 Notes
.....................................................

Use the latest production release of MySQL. Should you choose to use an
older release of MySQL on UnixWare 7.1.x, you must use a version of
MySQL at least as recent as 3.22.13 to get fixes for some portability
and OS problems.

We have been able to compile MySQL with the following `configure'
command on UnixWare 7.1.x:

     CC="cc" CFLAGS="-I/usr/local/include" \
     CXX="CC" CXXFLAGS="-I/usr/local/include" \
     ./configure --prefix=/usr/local/mysql \
         --enable-thread-safe-client --with-berkeley-db=./bdb \
         --with-innodb --with-openssl --with-extra-charsets=complex

If you want to use `gcc', you must use `gcc' 2.95.3 or newer.

     CC=gcc CXX=g++ ... ./configure ...

The version of Berkeley DB that comes with either UnixWare 7.1.4 or
OpenServer 6.0.0 is not used when building MySQL.  MySQL instead uses
its own version of Berkeley DB. The `configure' command needs to build
both a static and a dynamic library in `SRC_DIRECTORY/bdb/build_unix/',
but it does not with MySQL's own `BDB' version. The workaround is as
follows.

  1. Configure as normal for MySQL.

  2. `cd bdb/build_unix/'

  3. `cp -p Makefile Makefile.sav'

  4. Use same options and run `../dist/configure'.

  5. Run `gmake'.

  6. `cp -p Makefile.sav Makefile'

  7. Change to top source directory and run `gmake'.

This enables both the shared and dynamic libraries to be made and work.

SCO provides operating system patches at
`ftp://ftp.sco.com/pub/unixware7' for UnixWare 7.1.1,
`ftp://ftp.sco.com/pub/unixware7/713/' for UnixWare 7.1.3,
`ftp://ftp.sco.com/pub/unixware7/714/' for UnixWare 7.1.4, and
`ftp://ftp.sco.com/pub/openunix8' for OpenUNIX 8.0.0.

SCO provides information about security fixes at
`ftp://ftp.sco.com/pub/security/OpenUNIX' for OpenUNIX and
`ftp://ftp.sco.com/pub/security/UnixWare' for UnixWare.

The UnixWare 7 file size limit is 1 TB with VXFS. Some OS utilities
have a limitation of 2GB.

On UnixWare 7.1.4 you do not need to do anything to get large file
support, but to enable large file support on prior versions of UnixWare
7.1.x, run `fsadm'.

     # fsadm -Fvxfs -o largefiles /
     # fsadm /         * Note
     # ulimit unlimited
     # /etc/conf/bin/idtune SFSZLIM 0x7FFFFFFF     ** Note
     # /etc/conf/bin/idtune HFSZLIM 0x7FFFFFFF     ** Note
     # /etc/conf/bin/idbuild -B

     * This should report "largefiles".
     ** 0x7FFFFFFF represents infinity for these values.

Reboot the system using `shutdown'.

By default, the entries in `/etc/conf/cf.d/mtune' are set as follows:

     Value           Default         Min             Max
     -----           -------         ---             ---
     SVMMLIM         0x9000000       0x1000000       0x7FFFFFFF
     HVMMLIM         0x9000000       0x1000000       0x7FFFFFFF

To make changes to the kernel, use the `idtune NAME PARAMETER' command.
`idtune' modifies the `/etc/conf/cf.d/stune' file for you. To set the
kernel values, execute the following commands as `root':

     # /etc/conf/bin/idtune SDATLIM 0x7FFFFFFF
     # /etc/conf/bin/idtune HDATLIM 0x7FFFFFFF
     # /etc/conf/bin/idtune SVMMLIM 0x7FFFFFFF
     # /etc/conf/bin/idtune HVMMLIM 0x7FFFFFFF
     # /etc/conf/bin/idtune SFNOLIM 2048
     # /etc/conf/bin/idtune HFNOLIM 2048

Then rebuild and reboot the kernel by issuing this command:

     # /etc/conf/bin/idbuild -B && init 6

To tune the system, the proper parameter values to use depend on the
number of users accessing the application or database and size the of
the database (that is, the used buffer pool).  The following kernel
parameters can be set with `idtune':

   * `SHMMAX' (recommended setting: 128MB) and `SHMSEG' (recommended
     setting: 15). These parameters have an influence on the MySQL
     database engine to create user buffer pools.

   * `SFNOLIM' and `HFNOLIM' should be at maximum 2048.

   * `NPROC' should be set to at least 3000/4000 (depends on number of
     users).

   * The following formulas are recommended to calculate values for
     `SEMMSL', `SEMMNS', and `SEMMNU':

          SEMMSL = 13

     13 is what has been found to be the best for both Progress and
     MySQL.

          SEMMNS = SEMMSL * NUMBER OF DB SERVERS TO BE RUN ON THE SYSTEM

     Set `SEMMNS' to the value of `SEMMSL' multiplied by the number of
     database servers (maximum) that you are running on the system at
     one time.

          SEMMNU = SEMMNS

     Set the value of `SEMMNU' to equal the value of `SEMMNS'. You
     could probably set this to 75% of `SEMMNS', but this is a
     conservative estimate.


File: manual.info,  Node: os-2,  Prev: other-unix-notes,  Up: operating-system-specific-notes

3.20.6 OS/2 Notes
-----------------

*Note*:

We no longer test builds on OS/2. The notes in this section are
provided for your information but may not work on your system.

MySQL uses quite a few open files. Because of this, you should add
something like the following to your `CONFIG.SYS' file:

     SET EMXOPT=-c -n -h1024

If you do not do this, you may encounter the following error:

     File 'XXXX' not found (Errcode: 24)

When using MySQL with OS/2 Warp 3, FixPack 29 or above is required.
With OS/2 Warp 4, FixPack 4 or above is required. This is a requirement
of the Pthreads library. MySQL must be installed on a partition with a
type that supports long file names, such as HPFS, FAT32, and so on.

The `INSTALL.CMD' script must be run from OS/2's own `CMD.EXE' and may
not work with replacement shells such as `4OS2.EXE'.

The `scripts/mysql-install-db' script has been renamed. It is called
`install.cmd' and is a REXX script, which sets up the default MySQL
security settings and creates the WorkPlace Shell icons for MySQL.

Dynamic module support is compiled in but not fully tested.  Dynamic
modules should be compiled using the Pthreads runtime library.

     gcc -Zdll -Zmt -Zcrtdll=pthrdrtl -I../include -I../regex -I.. \
         -o example udf_example.c -L../lib -lmysqlclient udf_example.def
     mv example.dll example.udf

*Note*:

Due to limitations in OS/2, UDF module name stems must not exceed eight
characters. Modules are stored in the `/mysql2/udf' directory; the
`safe-mysqld.cmd' script puts this directory in the `BEGINLIBPATH'
environment variable.  When using UDF modules, specified extensions are
ignored--it is assumed to be `.udf'. For example, in Unix, the shared
module might be named `example.so' and you would load a function from
it like this:

     mysql> CREATE FUNCTION metaphon RETURNS STRING SONAME 'example.so';

In OS/2, the module would be named `example.udf', but you would not
specify the module extension:

     mysql> CREATE FUNCTION metaphon RETURNS STRING SONAME 'example';


File: manual.info,  Node: environment-variables,  Next: perl-support,  Prev: operating-system-specific-notes,  Up: installing

3.21 Environment Variables
==========================

This section lists all the environment variables that are used directly
or indirectly by MySQL. Most of these can also be found in other places
in this manual.

Note that any options on the command line take precedence over values
specified in option files and environment variables, and values in
option files take precedence over values in environment variables.

In many cases, it is preferable to use an option file instead of
environment variables to modify the behavior of MySQL. See *Note
option-files::.

Variable           Description
`CXX'              The name of your C++ compiler (for running
                   `configure').
`CC'               The name of your C compiler (for running `configure').
`CFLAGS'           Flags for your C compiler (for running `configure').
`CXXFLAGS'         Flags for your C++ compiler (for running `configure').
`DBI_USER'         The default user name for Perl DBI.
`DBI_TRACE'        Trace options for Perl DBI.
`HOME'             The default path for the *Note `mysql': mysql.
                   history file is `$HOME/.mysql_history'.
`LD_RUN_PATH'      Used to specify the location of `libmysqlclient.so'.
`MYSQL_DEBUG'      Debug trace options when debugging.
`MYSQL_GROUP_SUFFIX'Option group suffix value (like specifying
                   `--defaults-group-suffix').
`MYSQL_HISTFILE'   The path to the *Note `mysql': mysql. history file.
                   If this variable is set, its value overrides the
                   default for `$HOME/.mysql_history'.
`MYSQL_HOME'       The path to the directory in which the server-specific
                   `my.cnf' file resides (as of MySQL 5.0.3).
`MYSQL_HOST'       The default host name used by the *Note `mysql':
                   mysql. command-line client.
`MYSQL_PS1'        The command prompt to use in the *Note `mysql':
                   mysql. command-line client.
`MYSQL_PWD'        The default password when connecting to *Note
                   `mysqld': mysqld. Note that using this is insecure.
                   See *Note password-security-user::.
`MYSQL_TCP_PORT'   The default TCP/IP port number.
`MYSQL_UNIX_PORT'  The default Unix socket file name; used for
                   connections to `localhost'.
`PATH'             Used by the shell to find MySQL programs.
`TMPDIR'           The directory where temporary files are created.
`TZ'               This should be set to your local time zone. See *Note
                   timezone-problems::.
`UMASK'            The user-file creation mode when creating files. See
                   note following table.
`UMASK_DIR'        The user-directory creation mode when creating
                   directories. See note following table.
`USER'             The default user name on Windows and NetWare when
                   connecting to *Note `mysqld': mysqld.

For information about the *Note `mysql': mysql. history file, see *Note
mysql-history-file::.

The `UMASK' and `UMASK_DIR' variables, despite their names, are used as
modes, not masks:

   * If `UMASK' is set, *Note `mysqld': mysqld.  uses `($UMASK | 0600)'
     as the mode for file creation, so that newly created files have a
     mode in the range from 0600 to 0666 (all values octal).

   * If `UMASK_DIR' is set, *Note `mysqld': mysqld. uses `($UMASK_DIR |
     0700)' as the base mode for directory creation, which then is
     AND-ed with `~(~$UMASK & 0666)', so that newly created directories
     have a mode in the range from 0700 to 0777 (all values octal). The
     AND operation may remove read and write permissions from the
     directory mode, but not execute permissions.

MySQL assumes that the value for `UMASK' or `UMASK_DIR' is in octal if
it starts with a zero.


File: manual.info,  Node: perl-support,  Prev: environment-variables,  Up: installing

3.22 Perl Installation Notes
============================

* Menu:

* perl-installation::            Installing Perl on Unix
* activestate-perl::             Installing ActiveState Perl on Windows
* perl-support-problems::        Problems Using the Perl `DBI'/`DBD' Interface

The Perl `DBI' module provides a generic interface for database access.
You can write a `DBI' script that works with many different database
engines without change. To use `DBI', you must install the `DBI'
module, as well as a DataBase Driver (DBD) module for each type of
databas server you want to access. For MySQL, this driver is the
`DBD::mysql' module.

Perl, and the `DBD::MySQL' module for `DBI' must be installed if you
want to run the MySQL benchmark scripts; see *Note mysql-benchmarks::.
They are also required for the MySQL Cluster *Note `ndb_size.pl':
mysql-cluster-programs-ndb-size-pl. utility; see *Note
mysql-cluster-programs-ndb-size-pl::.

*Note*:

Perl support is not included with MySQL distributions. You can obtain
the necessary modules from `http://search.cpan.org' for Unix, or by
using the ActiveState `ppm' program on Windows. The following sections
describe how to do this.

The `DBI'/`DBD' interface requires Perl 5.6.0, and 5.6.1 or later is
preferred. DBI _does not work_ if you have an older version of Perl.
You should use `DBD::mysql' 4.009 or higher. Although earlier versions
are available, they do not support the full functionality of MySQL 5.0.


File: manual.info,  Node: perl-installation,  Next: activestate-perl,  Prev: perl-support,  Up: perl-support

3.22.1 Installing Perl on Unix
------------------------------

MySQL Perl support requires that you have installed MySQL client
programming support (libraries and header files). Most installation
methods install the necessary files. If you install MySQL from RPM
files on Linux, be sure to install the developer RPM as well. The
client programs are in the client RPM, but client programming support
is in the developer RPM.

The files you need for Perl support can be obtained from the CPAN
(Comprehensive Perl Archive Network) at `http://search.cpan.org'.

The easiest way to install Perl modules on Unix is to use the `CPAN'
module. For example:

     shell> perl -MCPAN -e shell
     cpan> install DBI
     cpan> install DBD::mysql

The `DBD::mysql' installation runs a number of tests. These tests
attempt to connect to the local MySQL server using the default user
name and password. (The default user name is your login name on Unix,
and `ODBC' on Windows. The default password is `no password.') If you
cannot connect to the server with those values (for example, if your
account has a password), the tests fail. You can use `force install
DBD::mysql' to ignore the failed tests.

`DBI' requires the `Data::Dumper' module. It may be installed; if not,
you should install it before installing `DBI'.

It is also possible to download the module distributions in the form of
compressed `tar' archives and build the modules manually. For example,
to unpack and build a DBI distribution, use a procedure such as this:

  1. Unpack the distribution into the current directory:

          shell> gunzip < DBI-VERSION.tar.gz | tar xvf -

     This command creates a directory named `DBI-VERSION'.

  2. Change location into the top-level directory of the unpacked
     distribution:

          shell> cd DBI-VERSION

  3. Build the distribution and compile everything:

          shell> perl Makefile.PL
          shell> make
          shell> make test
          shell> make install

The `make test' command is important because it verifies that the
module is working. Note that when you run that command during the
`DBD::mysql' installation to exercise the interface code, the MySQL
server must be running or the test fails.

It is a good idea to rebuild and reinstall the `DBD::mysql'
distribution whenever you install a new release of MySQL. This ensures
that the latest versions of the MySQL client libraries are installed
correctly.

If you do not have access rights to install Perl modules in the system
directory or if you want to install local Perl modules, the following
reference may be useful:
`http://servers.digitaldaze.com/extensions/perl/modules.html#modules'

Look under the heading `Installing New Modules that Require Locally
Installed Modules.'


File: manual.info,  Node: activestate-perl,  Next: perl-support-problems,  Prev: perl-installation,  Up: perl-support

3.22.2 Installing ActiveState Perl on Windows
---------------------------------------------

On Windows, you should do the following to install the MySQL `DBD'
module with ActiveState Perl:

  1. Get ActiveState Perl from
     `http://www.activestate.com/Products/ActivePerl/' and install it.

  2. Open a console window.

  3. If necessary, set the `HTTP_proxy' variable.  For example, you
     might try a setting like this:

          C:\> set HTTP_proxy=my.proxy.com:3128

  4. Start the PPM program:

          C:\> C:\perl\bin\ppm.pl

  5. If you have not previously done so, install `DBI':

          ppm> install DBI

  6. If this succeeds, run the following command:

          ppm> install DBD-mysql

This procedure should work with ActiveState Perl 5.6 or newer.

If you cannot get the procedure to work, you should install the ODBC
driver instead and connect to the MySQL server through ODBC:

     use DBI;
     $dbh= DBI->connect("DBI:ODBC:$dsn",$user,$password) ||
       die "Got error $DBI::errstr when connecting to $dsn\n";


File: manual.info,  Node: perl-support-problems,  Prev: activestate-perl,  Up: perl-support

3.22.3 Problems Using the Perl `DBI'/`DBD' Interface
----------------------------------------------------

If Perl reports that it cannot find the `../mysql/mysql.so' module, the
problem is probably that Perl cannot locate the `libmysqlclient.so'
shared library. You should be able to fix this problem by one of the
following methods:

   * Compile the `DBD::mysql' distribution with `perl Makefile.PL
     -static -config' rather than `perl Makefile.PL'.

   * Copy `libmysqlclient.so' to the directory where your other shared
     libraries are located (probably `/usr/lib' or `/lib').

   * Modify the `-L' options used to compile `DBD::mysql' to reflect
     the actual location of `libmysqlclient.so'.

   * On Linux, you can add the path name of the directory where
     `libmysqlclient.so' is located to the `/etc/ld.so.conf' file.

   * Add the path name of the directory where `libmysqlclient.so' is
     located to the `LD_RUN_PATH' environment variable. Some systems
     use `LD_LIBRARY_PATH' instead.

Note that you may also need to modify the `-L' options if there are
other libraries that the linker fails to find. For example, if the
linker cannot find `libc' because it is in `/lib' and the link command
specifies `-L/usr/lib', change the `-L' option to `-L/lib' or add
`-L/lib' to the existing link command.

If you get the following errors from `DBD::mysql', you are probably
using `gcc' (or using an old binary compiled with `gcc'):

     /usr/bin/perl: can't resolve symbol '__moddi3'
     /usr/bin/perl: can't resolve symbol '__divdi3'

Add `-L/usr/lib/gcc-lib/... -lgcc' to the link command when the
`mysql.so' library gets built (check the output from `make' for
`mysql.so' when you compile the Perl client).  The `-L' option should
specify the path name of the directory where `libgcc.a' is located on
your system.

Another cause of this problem may be that Perl and MySQL are not both
compiled with `gcc'. In this case, you can solve the mismatch by
compiling both with `gcc'.

You may see the following error from `DBD::mysql' when you run the
tests:

     t/00base............install_driver(mysql) failed:
     Can't load '../blib/arch/auto/DBD/mysql/mysql.so' for module DBD::mysql:
     ../blib/arch/auto/DBD/mysql/mysql.so: undefined symbol:
     uncompress at /usr/lib/perl5/5.00503/i586-linux/DynaLoader.pm line 169.

This means that you need to include the `-lz' compression library on
the link line. That can be done by changing the following line in the
file `lib/DBD/mysql/Install.pm':

     $sysliblist .= " -lm";

Change that line to:

     $sysliblist .= " -lm -lz";

After this, you _must_ run `make realclean' and then proceed with the
installation from the beginning.

If you want to install DBI on SCO, you have to edit the `Makefile' in
DBI-XXX and each subdirectory. Note that the following assumes `gcc'
2.95.2 or newer:

     OLD:                                  NEW:
     CC = cc                               CC = gcc
     CCCDLFLAGS = -KPIC -W1,-Bexport       CCCDLFLAGS = -fpic
     CCDLFLAGS = -wl,-Bexport              CCDLFLAGS =

     LD = ld                               LD = gcc -G -fpic
     LDDLFLAGS = -G -L/usr/local/lib       LDDLFLAGS = -L/usr/local/lib
     LDFLAGS = -belf -L/usr/local/lib      LDFLAGS = -L/usr/local/lib

     LD = ld                               LD = gcc -G -fpic
     OPTIMISE = -Od                        OPTIMISE = -O1

     OLD:
     CCCFLAGS = -belf -dy -w0 -U M_XENIX -DPERL_SCO5 -I/usr/local/include

     NEW:
     CCFLAGS = -U M_XENIX -DPERL_SCO5 -I/usr/local/include

These changes are necessary because the Perl dynaloader does not load
the `DBI' modules if they were compiled with `icc' or `cc'.

If you want to use the Perl module on a system that does not support
dynamic linking (such as SCO), you can generate a static version of
Perl that includes `DBI' and `DBD::mysql'. The way this works is that
you generate a version of Perl with the `DBI' code linked in and
install it on top of your current Perl. Then you use that to build a
version of Perl that additionally has the `DBD' code linked in, and
install that.

On SCO, you must have the following environment variables set:

     LD_LIBRARY_PATH=/lib:/usr/lib:/usr/local/lib:/usr/progressive/lib

Or:

     LD_LIBRARY_PATH=/usr/lib:/lib:/usr/local/lib:/usr/ccs/lib:\
         /usr/progressive/lib:/usr/skunk/lib
     LIBPATH=/usr/lib:/lib:/usr/local/lib:/usr/ccs/lib:\
         /usr/progressive/lib:/usr/skunk/lib
     MANPATH=scohelp:/usr/man:/usr/local1/man:/usr/local/man:\
         /usr/skunk/man:

First, create a Perl that includes a statically linked `DBI' module by
running these commands in the directory where your `DBI' distribution is
located:

     shell> perl Makefile.PL -static -config
     shell> make
     shell> make install
     shell> make perl

Then, you must install the new Perl. The output of `make perl'
indicates the exact `make' command you need to execute to perform the
installation. On SCO, this is `make -f Makefile.aperl inst_perl
MAP_TARGET=perl'.

Next, use the just-created Perl to create another Perl that also
includes a statically linked `DBD::mysql' by running these commands in
the directory where your `DBD::mysql' distribution is located:

     shell> perl Makefile.PL -static -config
     shell> make
     shell> make install
     shell> make perl

Finally, you should install this new Perl. Again, the output of `make
perl' indicates the command to use.


File: manual.info,  Node: tutorial,  Next: programs,  Prev: installing,  Up: Top

4 Tutorial
**********

* Menu:

* connecting-disconnecting::     Connecting to and Disconnecting from the Server
* entering-queries::             Entering Queries
* database-use::                 Creating and Using a Database
* getting-information::          Getting Information About Databases and Tables
* batch-mode::                   Using `mysql' in Batch Mode
* examples::                     Examples of Common Queries
* apache::                       Using MySQL with Apache

This chapter provides a tutorial introduction to MySQL by showing how
to use the *Note `mysql': mysql. client program to create and use a
simple database. *Note `mysql': mysql. (sometimes referred to as the
`terminal monitor' or just `monitor') is an interactive program that
enables you to connect to a MySQL server, run queries, and view the
results.  *Note `mysql': mysql. may also be used in batch mode: you
place your queries in a file beforehand, then tell *Note `mysql':
mysql. to execute the contents of the file. Both ways of using *Note
`mysql': mysql. are covered here.

To see a list of options provided by *Note `mysql': mysql, invoke it
with the `--help' option:

     shell> mysql --help

This chapter assumes that *Note `mysql': mysql. is installed on your
machine and that a MySQL server is available to which you can connect.
If this is not true, contact your MySQL administrator. (If _you_ are
the administrator, you need to consult the relevant portions of this
manual, such as *Note server-administration::.)

This chapter describes the entire process of setting up and using a
database. If you are interested only in accessing an existing database,
you may want to skip over the sections that describe how to create the
database and the tables it contains.

Because this chapter is tutorial in nature, many details are
necessarily omitted. Consult the relevant sections of the manual for
more information on the topics covered here.


File: manual.info,  Node: connecting-disconnecting,  Next: entering-queries,  Prev: tutorial,  Up: tutorial

4.1 Connecting to and Disconnecting from the Server
===================================================

To connect to the server, you will usually need to provide a MySQL user
name when you invoke *Note `mysql': mysql. and, most likely, a
password. If the server runs on a machine other than the one where you
log in, you will also need to specify a host name.  Contact your
administrator to find out what connection parameters you should use to
connect (that is, what host, user name, and password to use). Once you
know the proper parameters, you should be able to connect like this:

     shell> mysql -h HOST -u USER -p
     Enter password: ********

`host' and `user' represent the host name where your MySQL server is
running and the user name of your MySQL account. Substitute appropriate
values for your setup.  The `********' represents your password; enter
it when *Note `mysql': mysql. displays the `Enter password:' prompt.

If that works, you should see some introductory information followed by
a `mysql>' prompt:

     shell> mysql -h HOST -u USER -p
     Enter password: ********
     Welcome to the MySQL monitor.  Commands end with ; or \g.
     Your MySQL connection id is 25338 to server version: 5.0.95-standard

     Type 'help;' or '\h' for help. Type '\c' to clear the buffer.

     mysql>

The `mysql>' prompt tells you that *Note `mysql': mysql. is ready for
you to enter commands.

If you are logging in on the same machine that MySQL is running on, you
can omit the host, and simply use the following:

     shell> mysql -u USER -p

If, when you attempt to log in, you get an error message such as `ERROR
2002 (HY000): Can't connect to local MySQL server through socket
'/tmp/mysql.sock' (2)', it means that the MySQL server daemon (Unix) or
service (Windows) is not running. Consult the administrator or see the
section of *Note installing:: that is appropriate to your operating
system.

For help with other problems often encountered when trying to log in,
see *Note common-errors::.

Some MySQL installations permit users to connect as the anonymous
(unnamed) user to the server running on the local host. If this is the
case on your machine, you should be able to connect to that server by
invoking *Note `mysql': mysql. without any options:

     shell> mysql

After you have connected successfully, you can disconnect any time by
typing `QUIT' (or `\q') at the `mysql>' prompt:

     mysql> QUIT
     Bye

On Unix, you can also disconnect by pressing Control+D.

Most examples in the following sections assume that you are connected
to the server. They indicate this by the `mysql>' prompt.


File: manual.info,  Node: entering-queries,  Next: database-use,  Prev: connecting-disconnecting,  Up: tutorial

4.2 Entering Queries
====================

Make sure that you are connected to the server, as discussed in the
previous section. Doing so does not in itself select any database to
work with, but that is okay. At this point, it is more important to
find out a little about how to issue queries than to jump right in
creating tables, loading data into them, and retrieving data from them.
This section describes the basic principles of entering commands, using
several queries you can try out to familiarize yourself with how *Note
`mysql': mysql.  works.

Here is a simple command that asks the server to tell you its version
number and the current date. Type it in as shown here following the
`mysql>' prompt and press Enter:

     mysql> SELECT VERSION(), CURRENT_DATE;
     +----------------+--------------+
     | VERSION()      | CURRENT_DATE |
     +----------------+--------------+
     | 5.0.7-beta-Max | 2005-07-11   |
     +----------------+--------------+
     1 row in set (0.01 sec)
     mysql>

This query illustrates several things about *Note `mysql': mysql.:

   * A command normally consists of an SQL statement followed by a
     semicolon. (There are some exceptions where a semicolon may be
     omitted. `QUIT', mentioned earlier, is one of them. We'll get to
     others later.)

   * When you issue a command, *Note `mysql': mysql. sends it to the
     server for execution and displays the results, then prints another
     `mysql>' prompt to indicate that it is ready for another command.

   * *Note `mysql': mysql. displays query output in tabular form (rows
     and columns). The first row contains labels for the columns. The
     rows following are the query results. Normally, column labels are
     the names of the columns you fetch from database tables. If you're
     retrieving the value of an expression rather than a table column
     (as in the example just shown), *Note `mysql': mysql. labels the
     column using the expression itself.

   * *Note `mysql': mysql. shows how many rows were returned and how
     long the query took to execute, which gives you a rough idea of
     server performance. These values are imprecise because they
     represent wall clock time (not CPU or machine time), and because
     they are affected by factors such as server load and network
     latency. (For brevity, the `rows in set' line is sometimes not
     shown in the remaining examples in this chapter.)

Keywords may be entered in any lettercase. The following queries are
equivalent:

     mysql> SELECT VERSION(), CURRENT_DATE;
     mysql> select version(), current_date;
     mysql> SeLeCt vErSiOn(), current_DATE;

Here is another query. It demonstrates that you can use *Note `mysql':
mysql. as a simple calculator:

     mysql> SELECT SIN(PI()/4), (4+1)*5;
     +------------------+---------+
     | SIN(PI()/4)      | (4+1)*5 |
     +------------------+---------+
     | 0.70710678118655 |      25 |
     +------------------+---------+
     1 row in set (0.02 sec)

The queries shown thus far have been relatively short, single-line
statements. You can even enter multiple statements on a single line.
Just end each one with a semicolon:

     mysql> SELECT VERSION(); SELECT NOW();
     +----------------+
     | VERSION()      |
     +----------------+
     | 5.0.7-beta-Max |
     +----------------+
     1 row in set (0.00 sec)

     +---------------------+
     | NOW()               |
     +---------------------+
     | 2005-07-11 17:59:36 |
     +---------------------+
     1 row in set (0.00 sec)

A command need not be given all on a single line, so lengthy commands
that require several lines are not a problem.  *Note `mysql': mysql.
determines where your statement ends by looking for the terminating
semicolon, not by looking for the end of the input line. (In other
words, *Note `mysql': mysql.  accepts free-format input: it collects
input lines but does not execute them until it sees the semicolon.)

Here is a simple multiple-line statement:

     mysql> SELECT
         -> USER()
         -> ,
         -> CURRENT_DATE;
     +---------------+--------------+
     | USER()        | CURRENT_DATE |
     +---------------+--------------+
     | jon@localhost | 2005-07-11   |
     +---------------+--------------+

In this example, notice how the prompt changes from `mysql>' to `->'
after you enter the first line of a multiple-line query. This is how
*Note `mysql': mysql. indicates that it has not yet seen a complete
statement and is waiting for the rest. The prompt is your friend,
because it provides valuable feedback. If you use that feedback, you
can always be aware of what *Note `mysql': mysql.  is waiting for.

If you decide you do not want to execute a command that you are in the
process of entering, cancel it by typing `\c':

     mysql> SELECT
         -> USER()
         -> \c
     mysql>

Here, too, notice the prompt. It switches back to `mysql>' after you
type `\c', providing feedback to indicate that *Note `mysql': mysql. is
ready for a new command.

The following table shows each of the prompts you may see and
summarizes what they mean about the state that *Note `mysql': mysql. is
in.

Prompt  Meaning
`mysql>'Ready for new command.
`->'    Waiting for next line of multiple-line command.
`'>'    Waiting for next line, waiting for completion of a string
        that began with a single quote (``''').
`">'    Waiting for next line, waiting for completion of a string
        that began with a double quote (``"'').
``>'    Waiting for next line, waiting for completion of an
        identifier that began with a backtick (```'').
`/*>'   Waiting for next line, waiting for completion of a
        comment that began with `/*'.

In the MySQL 5.0 series, the `/*>' prompt was implemented in MySQL
5.0.6.

Multiple-line statements commonly occur by accident when you intend to
issue a command on a single line, but forget the terminating semicolon.
In this case, *Note `mysql': mysql.  waits for more input:

     mysql> SELECT USER()
         ->

If this happens to you (you think you've entered a statement but the
only response is a `->' prompt), most likely *Note `mysql': mysql. is
waiting for the semicolon. If you don't notice what the prompt is
telling you, you might sit there for a while before realizing what you
need to do. Enter a semicolon to complete the statement, and *Note
`mysql': mysql.  executes it:

     mysql> SELECT USER()
         -> ;
     +---------------+
     | USER()        |
     +---------------+
     | jon@localhost |
     +---------------+

The `'>' and `">' prompts occur during string collection (another way
of saying that MySQL is waiting for completion of a string). In MySQL,
you can write strings surrounded by either ``''' or ``"'' characters
(for example, `'hello'' or `"goodbye"'), and *Note `mysql': mysql. lets
you enter strings that span multiple lines. When you see a `'>' or `">'
prompt, it means that you have entered a line containing a string that
begins with a ``''' or ``"'' quote character, but have not yet entered
the matching quote that terminates the string. This often indicates
that you have inadvertently left out a quote character. For example:

     mysql> SELECT * FROM my_table WHERE name = 'Smith AND age < 30;
         '>

If you enter this *Note `SELECT': select. statement, then press `Enter'
and wait for the result, nothing happens. Instead of wondering why this
query takes so long, notice the clue provided by the `'>' prompt. It
tells you that *Note `mysql': mysql. expects to see the rest of an
unterminated string. (Do you see the error in the statement? The string
`'Smith' is missing the second single quotation mark.)

At this point, what do you do? The simplest thing is to cancel the
command. However, you cannot just type `\c' in this case, because *Note
`mysql': mysql. interprets it as part of the string that it is
collecting. Instead, enter the closing quote character (so *Note
`mysql': mysql. knows you've finished the string), then type `\c':

     mysql> SELECT * FROM my_table WHERE name = 'Smith AND age < 30;
         '> '\c
     mysql>

The prompt changes back to `mysql>', indicating that *Note `mysql':
mysql. is ready for a new command.

The ``>' prompt is similar to the `'>' and `">' prompts, but indicates
that you have begun but not completed a backtick-quoted identifier.

It is important to know what the `'>', `">', and ``>' prompts signify,
because if you mistakenly enter an unterminated string, any further
lines you type appear to be ignored by *Note `mysql': mysql.--including
a line containing `QUIT'. This can be quite confusing, especially if
you do not know that you need to supply the terminating quote before
you can cancel the current command.


File: manual.info,  Node: database-use,  Next: getting-information,  Prev: entering-queries,  Up: tutorial

4.3 Creating and Using a Database
=================================

* Menu:

* creating-database::            Creating and Selecting a Database
* creating-tables::              Creating a Table
* loading-tables::               Loading Data into a Table
* retrieving-data::              Retrieving Information from a Table

Once you know how to enter commands, you are ready to access a database.

Suppose that you have several pets in your home (your menagerie) and
you would like to keep track of various types of information about
them. You can do so by creating tables to hold your data and loading
them with the desired information. Then you can answer different sorts
of questions about your animals by retrieving data from the tables.
This section shows you how to perform the following operations:

   * Create a database

   * Create a table

   * Load data into the table

   * Retrieve data from the table in various ways

   * Use multiple tables

The menagerie database is simple (deliberately), but it is not
difficult to think of real-world situations in which a similar type of
database might be used. For example, a database like this could be used
by a farmer to keep track of livestock, or by a veterinarian to keep
track of patient records. A menagerie distribution containing some of
the queries and sample data used in the following sections can be
obtained from the MySQL Web site.  It is available in both compressed
`tar' file and Zip formats at `http://dev.mysql.com/doc/'.

Use the *Note `SHOW': show. statement to find out what databases
currently exist on the server:

     mysql> SHOW DATABASES;
     +----------+
     | Database |
     +----------+
     | mysql    |
     | test     |
     | tmp      |
     +----------+

The `mysql' database describes user access privileges. The `test'
database often is available as a workspace for users to try things out.

The list of databases displayed by the statement may be different on
your machine; *Note `SHOW DATABASES': show-databases.  does not show
databases that you have no privileges for if you do not have the *Note
`SHOW DATABASES': show-databases.  privilege. See *Note
show-databases::.

If the `test' database exists, try to access it:

     mysql> USE test
     Database changed

*Note `USE': use, like `QUIT', does not require a semicolon. (You can
terminate such statements with a semicolon if you like; it does no
harm.) The *Note `USE': use. statement is special in another way, too:
it must be given on a single line.

You can use the `test' database (if you have access to it) for the
examples that follow, but anything you create in that database can be
removed by anyone else with access to it. For this reason, you should
probably ask your MySQL administrator for permission to use a database
of your own.  Suppose that you want to call yours `menagerie'.  The
administrator needs to execute a command like this:

     mysql> GRANT ALL ON menagerie.* TO 'your_mysql_name'@'your_client_host';

where `your_mysql_name' is the MySQL user name assigned to you and
`your_client_host' is the host from which you connect to the server.


File: manual.info,  Node: creating-database,  Next: creating-tables,  Prev: database-use,  Up: database-use

4.3.1 Creating and Selecting a Database
---------------------------------------

If the administrator creates your database for you when setting up your
permissions, you can begin using it. Otherwise, you need to create it
yourself:

     mysql> CREATE DATABASE menagerie;

Under Unix, database names are case sensitive (unlike SQL keywords), so
you must always refer to your database as `menagerie', not as
`Menagerie', `MENAGERIE', or some other variant. This is also true for
table names. (Under Windows, this restriction does not apply, although
you must refer to databases and tables using the same lettercase
throughout a given query. However, for a variety of reasons, the
recommended best practice is always to use the same lettercase that was
used when the database was created.)

*Note*:

If you get an error such as `ERROR 1044 (42000): Access denied for user
'monty'@'localhost' to database 'menagerie'' when attempting to create
a database, this means that your user account does not have the
necessary privileges to do so. Discuss this with the administrator or
see *Note privilege-system::.

Creating a database does not select it for use; you must do that
explicitly. To make `menagerie' the current database, use this command:

     mysql> USE menagerie
     Database changed

Your database needs to be created only once, but you must select it for
use each time you begin a *Note `mysql': mysql.  session. You can do
this by issuing a *Note `USE': use. statement as shown in the example.
Alternatively, you can select the database on the command line when you
invoke *Note `mysql': mysql. Just specify its name after any connection
parameters that you might need to provide. For example:

     shell> mysql -h HOST -u USER -p menagerie
     Enter password: ********

*Important*:

`menagerie' in the command just shown is *not* your password. If you
want to supply your password on the command line after the `-p' option,
you must do so with no intervening space (for example, as
`-pmypassword', not as `-p mypassword'). However, putting your password
on the command line is not recommended, because doing so exposes it to
snooping by other users logged in on your machine.

*Note*:

You can see at any time which database is currently selected using
*Note `SELECT': select.  `DATABASE()'.


File: manual.info,  Node: creating-tables,  Next: loading-tables,  Prev: creating-database,  Up: database-use

4.3.2 Creating a Table
----------------------

Creating the database is the easy part, but at this point it is empty,
as *Note `SHOW TABLES': show-tables. tells you:

     mysql> SHOW TABLES;
     Empty set (0.00 sec)

The harder part is deciding what the structure of your database should
be: what tables you need and what columns should be in each of them.

You want a table that contains a record for each of your pets.  This
can be called the `pet' table, and it should contain, as a bare
minimum, each animal's name. Because the name by itself is not very
interesting, the table should contain other information. For example,
if more than one person in your family keeps pets, you might want to
list each animal's owner. You might also want to record some basic
descriptive information such as species and sex.

How about age? That might be of interest, but it is not a good thing to
store in a database. Age changes as time passes, which means you'd have
to update your records often. Instead, it is better to store a fixed
value such as date of birth. Then, whenever you need age, you can
calculate it as the difference between the current date and the birth
date. MySQL provides functions for doing date arithmetic, so this is
not difficult.  Storing birth date rather than age has other
advantages, too:

   * You can use the database for tasks such as generating reminders
     for upcoming pet birthdays. (If you think this type of query is
     somewhat silly, note that it is the same question you might ask in
     the context of a business database to identify clients to whom you
     need to send out birthday greetings in the current week or month,
     for that computer-assisted personal touch.)

   * You can calculate age in relation to dates other than the current
     date. For example, if you store death date in the database, you
     can easily calculate how old a pet was when it died.

You can probably think of other types of information that would be
useful in the `pet' table, but the ones identified so far are
sufficient: name, owner, species, sex, birth, and death.

Use a *Note `CREATE TABLE': create-table. statement to specify the
layout of your table:

     mysql> CREATE TABLE pet (name VARCHAR(20), owner VARCHAR(20),
         -> species VARCHAR(20), sex CHAR(1), birth DATE, death DATE);

*Note `VARCHAR': char. is a good choice for the `name', `owner', and
`species' columns because the column values vary in length. The lengths
in those column definitions need not all be the same, and need not be
`20'. You can normally pick any length from `1' to `65535', whatever
seems most reasonable to you.

*Note*:

Prior to MySQL 5.0.3, the upper limit was 255.) If you make a poor
choice and it turns out later that you need a longer field, MySQL
provides an *Note `ALTER TABLE': alter-table. statement.

Several types of values can be chosen to represent sex in animal
records, such as `'m'' and `'f'', or perhaps `'male'' and `'female''.
It is simplest to use the single characters `'m'' and `'f''.

The use of the *Note `DATE': datetime. data type for the `birth' and
`death' columns is a fairly obvious choice.

Once you have created a table, *Note `SHOW TABLES': show-tables. should
produce some output:

     mysql> SHOW TABLES;
     +---------------------+
     | Tables in menagerie |
     +---------------------+
     | pet                 |
     +---------------------+

To verify that your table was created the way you expected, use a *Note
`DESCRIBE': describe. statement:

     mysql> DESCRIBE pet;
     +---------+-------------+------+-----+---------+-------+
     | Field   | Type        | Null | Key | Default | Extra |
     +---------+-------------+------+-----+---------+-------+
     | name    | varchar(20) | YES  |     | NULL    |       |
     | owner   | varchar(20) | YES  |     | NULL    |       |
     | species | varchar(20) | YES  |     | NULL    |       |
     | sex     | char(1)     | YES  |     | NULL    |       |
     | birth   | date        | YES  |     | NULL    |       |
     | death   | date        | YES  |     | NULL    |       |
     +---------+-------------+------+-----+---------+-------+

You can use *Note `DESCRIBE': describe. any time, for example, if you
forget the names of the columns in your table or what types they have.

For more information about MySQL data types, see *Note data-types::.


File: manual.info,  Node: loading-tables,  Next: retrieving-data,  Prev: creating-tables,  Up: database-use

4.3.3 Loading Data into a Table
-------------------------------

After creating your table, you need to populate it. The *Note `LOAD
DATA': load-data. and *Note `INSERT': insert. statements are useful for
this.

Suppose that your pet records can be described as shown here.  (Observe
that MySQL expects dates in `'YYYY-MM-DD'' format; this may be different
from what you are used to.)

name    owner   species sex  birth          death
Fluffy  Harold  cat     f    1993-02-04     
Claws   Gwen    cat     m    1994-03-17     
Buffy   Harold  dog     f    1989-05-13     
Fang    Benny   dog     m    1990-08-27     
Bowser  Diane   dog     m    1979-08-31     1995-07-29
Chirpy  Gwen    bird    f    1998-09-11     
WhistlerGwen    bird         1997-12-09     
Slim    Benny   snake   m    1996-04-29     

Because you are beginning with an empty table, an easy way to populate
it is to create a text file containing a row for each of your animals,
then load the contents of the file into the table with a single
statement.

You could create a text file `pet.txt' containing one record per line,
with values separated by tabs, and given in the order in which the
columns were listed in the *Note `CREATE TABLE': create-table.
statement. For missing values (such as unknown sexes or death dates for
animals that are still living), you can use `NULL' values. To represent
these in your text file, use `\N' (backslash, capital-N). For example,
the record for Whistler the bird would look like this (where the
whitespace between values is a single tab character):

     Whistler        Gwen    bird    \N      1997-12-09      \N

To load the text file `pet.txt' into the `pet' table, use this
statement:

     mysql> LOAD DATA LOCAL INFILE '/path/pet.txt' INTO TABLE pet;

If you created the file on Windows with an editor that uses `\r\n' as a
line terminator, you should use this statement instead:

     mysql> LOAD DATA LOCAL INFILE '/path/pet.txt' INTO TABLE pet
         -> LINES TERMINATED BY '\r\n';

(On an Apple machine running OS X, you would likely want to use `LINES
TERMINATED BY '\r''.)

You can specify the column value separator and end of line marker
explicitly in the *Note `LOAD DATA': load-data. statement if you wish,
but the defaults are tab and linefeed. These are sufficient for the
statement to read the file `pet.txt' properly.

If the statement fails, it is likely that your MySQL installation does
not have local file capability enabled by default. See *Note
load-data-local::, for information on how to change this.

When you want to add new records one at a time, the *Note `INSERT':
insert. statement is useful. In its simplest form, you supply values
for each column, in the order in which the columns were listed in the
*Note `CREATE TABLE': create-table. statement. Suppose that Diane gets
a new hamster named `Puffball.' You could add a new record using an
*Note `INSERT': insert. statement like this:

     mysql> INSERT INTO pet
         -> VALUES ('Puffball','Diane','hamster','f','1999-03-30',NULL);

String and date values are specified as quoted strings here.  Also,
with *Note `INSERT': insert, you can insert `NULL' directly to
represent a missing value.  You do not use `\N' like you do with *Note
`LOAD DATA': load-data.

From this example, you should be able to see that there would be a lot
more typing involved to load your records initially using several *Note
`INSERT': insert. statements rather than a single *Note `LOAD DATA':
load-data.  statement.


File: manual.info,  Node: retrieving-data,  Prev: loading-tables,  Up: database-use

4.3.4 Retrieving Information from a Table
-----------------------------------------

* Menu:

* selecting-all::                Selecting All Data
* selecting-rows::               Selecting Particular Rows
* selecting-columns::            Selecting Particular Columns
* sorting-rows::                 Sorting Rows
* date-calculations::            Date Calculations
* working-with-null::            Working with `NULL' Values
* pattern-matching::             Pattern Matching
* counting-rows::                Counting Rows
* multiple-tables::              Using More Than one Table

The *Note `SELECT': select. statement is used to pull information from
a table. The general form of the statement is:

     SELECT WHAT_TO_SELECT
     FROM WHICH_TABLE
     WHERE CONDITIONS_TO_SATISFY;

WHAT_TO_SELECT indicates what you want to see. This can be a list of
columns, or `*' to indicate `all columns.' WHICH_TABLE indicates the
table from which you want to retrieve data. The `WHERE' clause is
optional. If it is present, CONDITIONS_TO_SATISFY specifies one or more
conditions that rows must satisfy to qualify for retrieval.


File: manual.info,  Node: selecting-all,  Next: selecting-rows,  Prev: retrieving-data,  Up: retrieving-data

4.3.4.1 Selecting All Data
..........................

The simplest form of *Note `SELECT': select.  retrieves everything from
a table:

     mysql> SELECT * FROM pet;
     +----------+--------+---------+------+------------+------------+
     | name     | owner  | species | sex  | birth      | death      |
     +----------+--------+---------+------+------------+------------+
     | Fluffy   | Harold | cat     | f    | 1993-02-04 | NULL       |
     | Claws    | Gwen   | cat     | m    | 1994-03-17 | NULL       |
     | Buffy    | Harold | dog     | f    | 1989-05-13 | NULL       |
     | Fang     | Benny  | dog     | m    | 1990-08-27 | NULL       |
     | Bowser   | Diane  | dog     | m    | 1979-08-31 | 1995-07-29 |
     | Chirpy   | Gwen   | bird    | f    | 1998-09-11 | NULL       |
     | Whistler | Gwen   | bird    | NULL | 1997-12-09 | NULL       |
     | Slim     | Benny  | snake   | m    | 1996-04-29 | NULL       |
     | Puffball | Diane  | hamster | f    | 1999-03-30 | NULL       |
     +----------+--------+---------+------+------------+------------+

This form of *Note `SELECT': select. is useful if you want to review
your entire table, for example, after you've just loaded it with your
initial data set. For example, you may happen to think that the birth
date for Bowser doesn't seem quite right. Consulting your original
pedigree papers, you find that the correct birth year should be 1989,
not 1979.

There are at least two ways to fix this:

   * Edit the file `pet.txt' to correct the error, then empty the table
     and reload it using *Note `DELETE': delete. and *Note `LOAD DATA':
     load-data.:

          mysql> DELETE FROM pet;
          mysql> LOAD DATA LOCAL INFILE 'pet.txt' INTO TABLE pet;

     However, if you do this, you must also re-enter the record for
     Puffball.

   * Fix only the erroneous record with an *Note `UPDATE': update.
     statement:

          mysql> UPDATE pet SET birth = '1989-08-31' WHERE name = 'Bowser';

     The *Note `UPDATE': update. changes only the record in question
     and does not require you to reload the table.


File: manual.info,  Node: selecting-rows,  Next: selecting-columns,  Prev: selecting-all,  Up: retrieving-data

4.3.4.2 Selecting Particular Rows
.................................

As shown in the preceding section, it is easy to retrieve an entire
table. Just omit the `WHERE' clause from the *Note `SELECT': select.
statement. But typically you don't want to see the entire table,
particularly when it becomes large. Instead, you're usually more
interested in answering a particular question, in which case you specify
some constraints on the information you want. Let's look at some
selection queries in terms of questions about your pets that they
answer.

You can select only particular rows from your table. For example, if
you want to verify the change that you made to Bowser's birth date,
select Bowser's record like this:

     mysql> SELECT * FROM pet WHERE name = 'Bowser';
     +--------+-------+---------+------+------------+------------+
     | name   | owner | species | sex  | birth      | death      |
     +--------+-------+---------+------+------------+------------+
     | Bowser | Diane | dog     | m    | 1989-08-31 | 1995-07-29 |
     +--------+-------+---------+------+------------+------------+

The output confirms that the year is correctly recorded as 1989, not
1979.

String comparisons normally are case-insensitive, so you can specify
the name as `'bowser'', `'BOWSER'', and so forth. The query result is
the same.

You can specify conditions on any column, not just `name'. For example,
if you want to know which animals were born during or after 1998, test
the `birth' column:

     mysql> SELECT * FROM pet WHERE birth >= '1998-1-1';
     +----------+-------+---------+------+------------+-------+
     | name     | owner | species | sex  | birth      | death |
     +----------+-------+---------+------+------------+-------+
     | Chirpy   | Gwen  | bird    | f    | 1998-09-11 | NULL  |
     | Puffball | Diane | hamster | f    | 1999-03-30 | NULL  |
     +----------+-------+---------+------+------------+-------+

You can combine conditions, for example, to locate female dogs:

     mysql> SELECT * FROM pet WHERE species = 'dog' AND sex = 'f';
     +-------+--------+---------+------+------------+-------+
     | name  | owner  | species | sex  | birth      | death |
     +-------+--------+---------+------+------------+-------+
     | Buffy | Harold | dog     | f    | 1989-05-13 | NULL  |
     +-------+--------+---------+------+------------+-------+

The preceding query uses the `AND' logical operator. There is also an
`OR' operator:

     mysql> SELECT * FROM pet WHERE species = 'snake' OR species = 'bird';
     +----------+-------+---------+------+------------+-------+
     | name     | owner | species | sex  | birth      | death |
     +----------+-------+---------+------+------------+-------+
     | Chirpy   | Gwen  | bird    | f    | 1998-09-11 | NULL  |
     | Whistler | Gwen  | bird    | NULL | 1997-12-09 | NULL  |
     | Slim     | Benny | snake   | m    | 1996-04-29 | NULL  |
     +----------+-------+---------+------+------------+-------+

`AND' and `OR' may be intermixed, although `AND' has higher precedence
than `OR'. If you use both operators, it is a good idea to use
parentheses to indicate explicitly how conditions should be grouped:

     mysql> SELECT * FROM pet WHERE (species = 'cat' AND sex = 'm')
         -> OR (species = 'dog' AND sex = 'f');
     +-------+--------+---------+------+------------+-------+
     | name  | owner  | species | sex  | birth      | death |
     +-------+--------+---------+------+------------+-------+
     | Claws | Gwen   | cat     | m    | 1994-03-17 | NULL  |
     | Buffy | Harold | dog     | f    | 1989-05-13 | NULL  |
     +-------+--------+---------+------+------------+-------+


File: manual.info,  Node: selecting-columns,  Next: sorting-rows,  Prev: selecting-rows,  Up: retrieving-data

4.3.4.3 Selecting Particular Columns
....................................

If you do not want to see entire rows from your table, just name the
columns in which you are interested, separated by commas. For example,
if you want to know when your animals were born, select the `name' and
`birth' columns:

     mysql> SELECT name, birth FROM pet;
     +----------+------------+
     | name     | birth      |
     +----------+------------+
     | Fluffy   | 1993-02-04 |
     | Claws    | 1994-03-17 |
     | Buffy    | 1989-05-13 |
     | Fang     | 1990-08-27 |
     | Bowser   | 1989-08-31 |
     | Chirpy   | 1998-09-11 |
     | Whistler | 1997-12-09 |
     | Slim     | 1996-04-29 |
     | Puffball | 1999-03-30 |
     +----------+------------+

To find out who owns pets, use this query:

     mysql> SELECT owner FROM pet;
     +--------+
     | owner  |
     +--------+
     | Harold |
     | Gwen   |
     | Harold |
     | Benny  |
     | Diane  |
     | Gwen   |
     | Gwen   |
     | Benny  |
     | Diane  |
     +--------+

Notice that the query simply retrieves the `owner' column from each
record, and some of them appear more than once. To minimize the output,
retrieve each unique output record just once by adding the keyword
`DISTINCT':

     mysql> SELECT DISTINCT owner FROM pet;
     +--------+
     | owner  |
     +--------+
     | Benny  |
     | Diane  |
     | Gwen   |
     | Harold |
     +--------+

You can use a `WHERE' clause to combine row selection with column
selection. For example, to get birth dates for dogs and cats only, use
this query:

     mysql> SELECT name, species, birth FROM pet
         -> WHERE species = 'dog' OR species = 'cat';
     +--------+---------+------------+
     | name   | species | birth      |
     +--------+---------+------------+
     | Fluffy | cat     | 1993-02-04 |
     | Claws  | cat     | 1994-03-17 |
     | Buffy  | dog     | 1989-05-13 |
     | Fang   | dog     | 1990-08-27 |
     | Bowser | dog     | 1989-08-31 |
     +--------+---------+------------+


File: manual.info,  Node: sorting-rows,  Next: date-calculations,  Prev: selecting-columns,  Up: retrieving-data

4.3.4.4 Sorting Rows
....................

You may have noticed in the preceding examples that the result rows are
displayed in no particular order. It is often easier to examine query
output when the rows are sorted in some meaningful way. To sort a
result, use an `ORDER BY' clause.

Here are animal birthdays, sorted by date:

     mysql> SELECT name, birth FROM pet ORDER BY birth;
     +----------+------------+
     | name     | birth      |
     +----------+------------+
     | Buffy    | 1989-05-13 |
     | Bowser   | 1989-08-31 |
     | Fang     | 1990-08-27 |
     | Fluffy   | 1993-02-04 |
     | Claws    | 1994-03-17 |
     | Slim     | 1996-04-29 |
     | Whistler | 1997-12-09 |
     | Chirpy   | 1998-09-11 |
     | Puffball | 1999-03-30 |
     +----------+------------+

On character type columns, sorting--like all other comparison
operations--is normally performed in a case-insensitive fashion. This
means that the order is undefined for columns that are identical except
for their case. You can force a case-sensitive sort for a column by
using `BINARY' like so: `ORDER BY BINARY COL_NAME'.

The default sort order is ascending, with smallest values first. To
sort in reverse (descending) order, add the `DESC' keyword to the name
of the column you are sorting by:

     mysql> SELECT name, birth FROM pet ORDER BY birth DESC;
     +----------+------------+
     | name     | birth      |
     +----------+------------+
     | Puffball | 1999-03-30 |
     | Chirpy   | 1998-09-11 |
     | Whistler | 1997-12-09 |
     | Slim     | 1996-04-29 |
     | Claws    | 1994-03-17 |
     | Fluffy   | 1993-02-04 |
     | Fang     | 1990-08-27 |
     | Bowser   | 1989-08-31 |
     | Buffy    | 1989-05-13 |
     +----------+------------+

You can sort on multiple columns, and you can sort different columns in
different directions. For example, to sort by type of animal in
ascending order, then by birth date within animal type in descending
order (youngest animals first), use the following query:

     mysql> SELECT name, species, birth FROM pet
         -> ORDER BY species, birth DESC;
     +----------+---------+------------+
     | name     | species | birth      |
     +----------+---------+------------+
     | Chirpy   | bird    | 1998-09-11 |
     | Whistler | bird    | 1997-12-09 |
     | Claws    | cat     | 1994-03-17 |
     | Fluffy   | cat     | 1993-02-04 |
     | Fang     | dog     | 1990-08-27 |
     | Bowser   | dog     | 1989-08-31 |
     | Buffy    | dog     | 1989-05-13 |
     | Puffball | hamster | 1999-03-30 |
     | Slim     | snake   | 1996-04-29 |
     +----------+---------+------------+

The `DESC' keyword applies only to the column name immediately
preceding it (`birth'); it does not affect the `species' column sort
order.


File: manual.info,  Node: date-calculations,  Next: working-with-null,  Prev: sorting-rows,  Up: retrieving-data

4.3.4.5 Date Calculations
.........................

MySQL provides several functions that you can use to perform
calculations on dates, for example, to calculate ages or extract parts
of dates.

To determine how many years old each of your pets is, compute the
difference in the year part of the current date and the birth date,
then subtract one if the current date occurs earlier in the calendar
year than the birth date. The following query shows, for each pet, the
birth date, the current date, and the age in years.

     mysql> SELECT name, birth, CURDATE(),
         -> (YEAR(CURDATE())-YEAR(birth))
         -> - (RIGHT(CURDATE(),5)<RIGHT(birth,5))
         -> AS age
         -> FROM pet;
     +----------+------------+------------+------+
     | name     | birth      | CURDATE()  | age  |
     +----------+------------+------------+------+
     | Fluffy   | 1993-02-04 | 2003-08-19 |   10 |
     | Claws    | 1994-03-17 | 2003-08-19 |    9 |
     | Buffy    | 1989-05-13 | 2003-08-19 |   14 |
     | Fang     | 1990-08-27 | 2003-08-19 |   12 |
     | Bowser   | 1989-08-31 | 2003-08-19 |   13 |
     | Chirpy   | 1998-09-11 | 2003-08-19 |    4 |
     | Whistler | 1997-12-09 | 2003-08-19 |    5 |
     | Slim     | 1996-04-29 | 2003-08-19 |    7 |
     | Puffball | 1999-03-30 | 2003-08-19 |    4 |
     +----------+------------+------------+------+

Here, `YEAR()' pulls out the year part of a date and `RIGHT()' pulls
off the rightmost five characters that represent the `MM-DD' (calendar
year) part of the date. The part of the expression that compares the
`MM-DD' values evaluates to 1 or 0, which adjusts the year difference
down a year if `CURDATE()' occurs earlier in the year than `birth'. The
full expression is somewhat ungainly, so an _alias_ (`age') is used to
make the output column label more meaningful.

The query works, but the result could be scanned more easily if the
rows were presented in some order. This can be done by adding an `ORDER
BY name' clause to sort the output by name:

     mysql> SELECT name, birth, CURDATE(),
         -> (YEAR(CURDATE())-YEAR(birth))
         -> - (RIGHT(CURDATE(),5)<RIGHT(birth,5))
         -> AS age
         -> FROM pet ORDER BY name;
     +----------+------------+------------+------+
     | name     | birth      | CURDATE()  | age  |
     +----------+------------+------------+------+
     | Bowser   | 1989-08-31 | 2003-08-19 |   13 |
     | Buffy    | 1989-05-13 | 2003-08-19 |   14 |
     | Chirpy   | 1998-09-11 | 2003-08-19 |    4 |
     | Claws    | 1994-03-17 | 2003-08-19 |    9 |
     | Fang     | 1990-08-27 | 2003-08-19 |   12 |
     | Fluffy   | 1993-02-04 | 2003-08-19 |   10 |
     | Puffball | 1999-03-30 | 2003-08-19 |    4 |
     | Slim     | 1996-04-29 | 2003-08-19 |    7 |
     | Whistler | 1997-12-09 | 2003-08-19 |    5 |
     +----------+------------+------------+------+

To sort the output by `age' rather than `name', just use a different
`ORDER BY' clause:

     mysql> SELECT name, birth, CURDATE(),
         -> (YEAR(CURDATE())-YEAR(birth))
         -> - (RIGHT(CURDATE(),5)<RIGHT(birth,5))
         -> AS age
         -> FROM pet ORDER BY age;
     +----------+------------+------------+------+
     | name     | birth      | CURDATE()  | age  |
     +----------+------------+------------+------+
     | Chirpy   | 1998-09-11 | 2003-08-19 |    4 |
     | Puffball | 1999-03-30 | 2003-08-19 |    4 |
     | Whistler | 1997-12-09 | 2003-08-19 |    5 |
     | Slim     | 1996-04-29 | 2003-08-19 |    7 |
     | Claws    | 1994-03-17 | 2003-08-19 |    9 |
     | Fluffy   | 1993-02-04 | 2003-08-19 |   10 |
     | Fang     | 1990-08-27 | 2003-08-19 |   12 |
     | Bowser   | 1989-08-31 | 2003-08-19 |   13 |
     | Buffy    | 1989-05-13 | 2003-08-19 |   14 |
     +----------+------------+------------+------+

A similar query can be used to determine age at death for animals that
have died. You determine which animals these are by checking whether
the `death' value is `NULL'. Then, for those with non-`NULL' values,
compute the difference between the `death' and `birth' values:

     mysql> SELECT name, birth, death,
         -> (YEAR(death)-YEAR(birth)) - (RIGHT(death,5)<RIGHT(birth,5))
         -> AS age
         -> FROM pet WHERE death IS NOT NULL ORDER BY age;
     +--------+------------+------------+------+
     | name   | birth      | death      | age  |
     +--------+------------+------------+------+
     | Bowser | 1989-08-31 | 1995-07-29 |    5 |
     +--------+------------+------------+------+

The query uses `death IS NOT NULL' rather than `death <> NULL' because
`NULL' is a special value that cannot be compared using the usual
comparison operators. This is discussed later. See *Note
working-with-null::.

What if you want to know which animals have birthdays next month? For
this type of calculation, year and day are irrelevant; you simply want
to extract the month part of the `birth' column. MySQL provides several
functions for extracting parts of dates, such as `YEAR()', `MONTH()',
and `DAYOFMONTH()'.  `MONTH()' is the appropriate function here. To see
how it works, run a simple query that displays the value of both
`birth' and `MONTH(birth)':

     mysql> SELECT name, birth, MONTH(birth) FROM pet;
     +----------+------------+--------------+
     | name     | birth      | MONTH(birth) |
     +----------+------------+--------------+
     | Fluffy   | 1993-02-04 |            2 |
     | Claws    | 1994-03-17 |            3 |
     | Buffy    | 1989-05-13 |            5 |
     | Fang     | 1990-08-27 |            8 |
     | Bowser   | 1989-08-31 |            8 |
     | Chirpy   | 1998-09-11 |            9 |
     | Whistler | 1997-12-09 |           12 |
     | Slim     | 1996-04-29 |            4 |
     | Puffball | 1999-03-30 |            3 |
     +----------+------------+--------------+

Finding animals with birthdays in the upcoming month is also simple.
Suppose that the current month is April. Then the month value is `4'
and you can look for animals born in May (month `5') like this:

     mysql> SELECT name, birth FROM pet WHERE MONTH(birth) = 5;
     +-------+------------+
     | name  | birth      |
     +-------+------------+
     | Buffy | 1989-05-13 |
     +-------+------------+

There is a small complication if the current month is December. You
cannot merely add one to the month number (`12') and look for animals
born in month `13', because there is no such month.  Instead, you look
for animals born in January (month `1').

You can write the query so that it works no matter what the current
month is, so that you do not have to use the number for a particular
month.  `DATE_ADD()' enables you to add a time interval to a given
date. If you add a month to the value of `CURDATE()', then extract the
month part with `MONTH()', the result produces the month in which to
look for birthdays:

     mysql> SELECT name, birth FROM pet
         -> WHERE MONTH(birth) = MONTH(DATE_ADD(CURDATE(),INTERVAL 1 MONTH));

A different way to accomplish the same task is to add `1' to get the
next month after the current one after using the modulo function (`MOD')
to wrap the month value to `0' if it is currently `12':

     mysql> SELECT name, birth FROM pet
         -> WHERE MONTH(birth) = MOD(MONTH(CURDATE()), 12) + 1;

`MONTH()' returns a number between `1' and `12'. And
`MOD(something,12)' returns a number between `0' and `11'.  So the
addition has to be after the `MOD()', otherwise we would go from
November (`11') to January (`1').


File: manual.info,  Node: working-with-null,  Next: pattern-matching,  Prev: date-calculations,  Up: retrieving-data

4.3.4.6 Working with `NULL' Values
..................................

The `NULL' value can be surprising until you get used to it.
Conceptually, `NULL' means `a missing unknown value' and it is treated
somewhat differently from other values. To test for `NULL', you cannot
use the arithmetic comparison operators such as `=', `<', or `<>'. To
demonstrate this for yourself, try the following query:

     mysql> SELECT 1 = NULL, 1 <> NULL, 1 < NULL, 1 > NULL;
     +----------+-----------+----------+----------+
     | 1 = NULL | 1 <> NULL | 1 < NULL | 1 > NULL |
     +----------+-----------+----------+----------+
     |     NULL |      NULL |     NULL |     NULL |
     +----------+-----------+----------+----------+

Clearly you get no meaningful results from these comparisons.  Use the
`IS NULL' and `IS NOT NULL' operators instead:

     mysql> SELECT 1 IS NULL, 1 IS NOT NULL;
     +-----------+---------------+
     | 1 IS NULL | 1 IS NOT NULL |
     +-----------+---------------+
     |         0 |             1 |
     +-----------+---------------+

In MySQL, `0' or `NULL' means false and anything else means true. The
default truth value from a boolean operation is `1'.

This special treatment of `NULL' is why, in the previous section, it
was necessary to determine which animals are no longer alive using
`death IS NOT NULL' instead of `death <> NULL'.

Two `NULL' values are regarded as equal in a `GROUP BY'.

When doing an `ORDER BY', `NULL' values are presented first if you do
`ORDER BY ... ASC' and last if you do `ORDER BY ... DESC'.

A common error when working with `NULL' is to assume that it is not
possible to insert a zero or an empty string into a column defined as
`NOT NULL', but this is not the case. These are in fact values, whereas
`NULL' means `not having a value.' You can test this easily enough by
using `IS [NOT] NULL' as shown:

     mysql> SELECT 0 IS NULL, 0 IS NOT NULL, '' IS NULL, '' IS NOT NULL;
     +-----------+---------------+------------+----------------+
     | 0 IS NULL | 0 IS NOT NULL | '' IS NULL | '' IS NOT NULL |
     +-----------+---------------+------------+----------------+
     |         0 |             1 |          0 |              1 |
     +-----------+---------------+------------+----------------+

Thus it is entirely possible to insert a zero or empty string into a
`NOT NULL' column, as these are in fact `NOT NULL'. See *Note
problems-with-null::.


File: manual.info,  Node: pattern-matching,  Next: counting-rows,  Prev: working-with-null,  Up: retrieving-data

4.3.4.7 Pattern Matching
........................

MySQL provides standard SQL pattern matching as well as a form of
pattern matching based on extended regular expressions similar to those
used by Unix utilities such as `vi', `grep', and `sed'.

SQL pattern matching enables you to use ``_'' to match any single
character and ``%'' to match an arbitrary number of characters
(including zero characters). In MySQL, SQL patterns are
case-insensitive by default. Some examples are shown here. You do not
use `=' or `<>' when you use SQL patterns; use the `LIKE' or `NOT LIKE'
comparison operators instead.

To find names beginning with ``b'':

     mysql> SELECT * FROM pet WHERE name LIKE 'b%';
     +--------+--------+---------+------+------------+------------+
     | name   | owner  | species | sex  | birth      | death      |
     +--------+--------+---------+------+------------+------------+
     | Buffy  | Harold | dog     | f    | 1989-05-13 | NULL       |
     | Bowser | Diane  | dog     | m    | 1989-08-31 | 1995-07-29 |
     +--------+--------+---------+------+------------+------------+

To find names ending with ``fy'':

     mysql> SELECT * FROM pet WHERE name LIKE '%fy';
     +--------+--------+---------+------+------------+-------+
     | name   | owner  | species | sex  | birth      | death |
     +--------+--------+---------+------+------------+-------+
     | Fluffy | Harold | cat     | f    | 1993-02-04 | NULL  |
     | Buffy  | Harold | dog     | f    | 1989-05-13 | NULL  |
     +--------+--------+---------+------+------------+-------+

To find names containing a ``w'':

     mysql> SELECT * FROM pet WHERE name LIKE '%w%';
     +----------+-------+---------+------+------------+------------+
     | name     | owner | species | sex  | birth      | death      |
     +----------+-------+---------+------+------------+------------+
     | Claws    | Gwen  | cat     | m    | 1994-03-17 | NULL       |
     | Bowser   | Diane | dog     | m    | 1989-08-31 | 1995-07-29 |
     | Whistler | Gwen  | bird    | NULL | 1997-12-09 | NULL       |
     +----------+-------+---------+------+------------+------------+

To find names containing exactly five characters, use five instances of
the ``_'' pattern character:

     mysql> SELECT * FROM pet WHERE name LIKE '_____';
     +-------+--------+---------+------+------------+-------+
     | name  | owner  | species | sex  | birth      | death |
     +-------+--------+---------+------+------------+-------+
     | Claws | Gwen   | cat     | m    | 1994-03-17 | NULL  |
     | Buffy | Harold | dog     | f    | 1989-05-13 | NULL  |
     +-------+--------+---------+------+------------+-------+

The other type of pattern matching provided by MySQL uses extended
regular expressions. When you test for a match for this type of
pattern, use the `REGEXP' and `NOT REGEXP' operators (or `RLIKE' and
`NOT RLIKE', which are synonyms).

The following list describes some characteristics of extended regular
expressions:

   * ``.'' matches any single character.

   * A character class ``[...]'' matches any character within the
     brackets. For example, ``[abc]'' matches ``a'', ``b'', or ``c''.
     To name a range of characters, use a dash.  ``[a-z]'' matches any
     letter, whereas ``[0-9]'' matches any digit.

   * ``*'' matches zero or more instances of the thing preceding it.
     For example, ``x*'' matches any number of ``x'' characters,
     ``[0-9]*'' matches any number of digits, and ``.*'' matches any
     number of anything.

   * A `REGEXP' pattern match succeeds if the pattern matches anywhere
     in the value being tested. (This differs from a `LIKE' pattern
     match, which succeeds only if the pattern matches the entire
     value.)

   * To anchor a pattern so that it must match the beginning or end of
     the value being tested, use ``^'' at the beginning or ``$'' at the
     end of the pattern.

To demonstrate how extended regular expressions work, the `LIKE'
queries shown previously are rewritten here to use `REGEXP'.

To find names beginning with ``b'', use ``^'' to match the beginning of
the name:

     mysql> SELECT * FROM pet WHERE name REGEXP '^b';
     +--------+--------+---------+------+------------+------------+
     | name   | owner  | species | sex  | birth      | death      |
     +--------+--------+---------+------+------------+------------+
     | Buffy  | Harold | dog     | f    | 1989-05-13 | NULL       |
     | Bowser | Diane  | dog     | m    | 1989-08-31 | 1995-07-29 |
     +--------+--------+---------+------+------------+------------+

If you really want to force a `REGEXP' comparison to be case sensitive,
use the `BINARY' keyword to make one of the strings a binary string.
This query matches only lowercase ``b'' at the beginning of a name:

     mysql> SELECT * FROM pet WHERE name REGEXP BINARY '^b';

To find names ending with ``fy'', use ``$'' to match the end of the
name:

     mysql> SELECT * FROM pet WHERE name REGEXP 'fy$';
     +--------+--------+---------+------+------------+-------+
     | name   | owner  | species | sex  | birth      | death |
     +--------+--------+---------+------+------------+-------+
     | Fluffy | Harold | cat     | f    | 1993-02-04 | NULL  |
     | Buffy  | Harold | dog     | f    | 1989-05-13 | NULL  |
     +--------+--------+---------+------+------------+-------+

To find names containing a ``w'', use this query:

     mysql> SELECT * FROM pet WHERE name REGEXP 'w';
     +----------+-------+---------+------+------------+------------+
     | name     | owner | species | sex  | birth      | death      |
     +----------+-------+---------+------+------------+------------+
     | Claws    | Gwen  | cat     | m    | 1994-03-17 | NULL       |
     | Bowser   | Diane | dog     | m    | 1989-08-31 | 1995-07-29 |
     | Whistler | Gwen  | bird    | NULL | 1997-12-09 | NULL       |
     +----------+-------+---------+------+------------+------------+

Because a regular expression pattern matches if it occurs anywhere in
the value, it is not necessary in the previous query to put a wildcard
on either side of the pattern to get it to match the entire value like
it would be if you used an SQL pattern.

To find names containing exactly five characters, use ``^'' and ``$''
to match the beginning and end of the name, and five instances of ``.''
in between:

     mysql> SELECT * FROM pet WHERE name REGEXP '^.....$';
     +-------+--------+---------+------+------------+-------+
     | name  | owner  | species | sex  | birth      | death |
     +-------+--------+---------+------+------------+-------+
     | Claws | Gwen   | cat     | m    | 1994-03-17 | NULL  |
     | Buffy | Harold | dog     | f    | 1989-05-13 | NULL  |
     +-------+--------+---------+------+------------+-------+

You could also write the previous query using the `{N}'
(`repeat-N-times') operator:

     mysql> SELECT * FROM pet WHERE name REGEXP '^.{5}$';
     +-------+--------+---------+------+------------+-------+
     | name  | owner  | species | sex  | birth      | death |
     +-------+--------+---------+------+------------+-------+
     | Claws | Gwen   | cat     | m    | 1994-03-17 | NULL  |
     | Buffy | Harold | dog     | f    | 1989-05-13 | NULL  |
     +-------+--------+---------+------+------------+-------+

*Note regexp::, provides more information about the syntax for regular
expressions.


File: manual.info,  Node: counting-rows,  Next: multiple-tables,  Prev: pattern-matching,  Up: retrieving-data

4.3.4.8 Counting Rows
.....................

Databases are often used to answer the question, `How often does a
certain type of data occur in a table?' For example, you might want to
know how many pets you have, or how many pets each owner has, or you
might want to perform various kinds of census operations on your
animals.

Counting the total number of animals you have is the same question as
`How many rows are in the `pet' table?' because there is one record per
pet. `COUNT(*)' counts the number of rows, so the query to count your
animals looks like this:

     mysql> SELECT COUNT(*) FROM pet;
     +----------+
     | COUNT(*) |
     +----------+
     |        9 |
     +----------+

Earlier, you retrieved the names of the people who owned pets.  You can
use `COUNT()' if you want to find out how many pets each owner has:

     mysql> SELECT owner, COUNT(*) FROM pet GROUP BY owner;
     +--------+----------+
     | owner  | COUNT(*) |
     +--------+----------+
     | Benny  |        2 |
     | Diane  |        2 |
     | Gwen   |        3 |
     | Harold |        2 |
     +--------+----------+

The preceding query uses `GROUP BY' to group all records for each
`owner'. The use of `COUNT()' in conjunction with `GROUP BY' is useful
for characterizing your data under various groupings. The following
examples show different ways to perform animal census operations.

Number of animals per species:

     mysql> SELECT species, COUNT(*) FROM pet GROUP BY species;
     +---------+----------+
     | species | COUNT(*) |
     +---------+----------+
     | bird    |        2 |
     | cat     |        2 |
     | dog     |        3 |
     | hamster |        1 |
     | snake   |        1 |
     +---------+----------+

Number of animals per sex:

     mysql> SELECT sex, COUNT(*) FROM pet GROUP BY sex;
     +------+----------+
     | sex  | COUNT(*) |
     +------+----------+
     | NULL |        1 |
     | f    |        4 |
     | m    |        4 |
     +------+----------+

(In this output, `NULL' indicates that the sex is unknown.)

Number of animals per combination of species and sex:

     mysql> SELECT species, sex, COUNT(*) FROM pet GROUP BY species, sex;
     +---------+------+----------+
     | species | sex  | COUNT(*) |
     +---------+------+----------+
     | bird    | NULL |        1 |
     | bird    | f    |        1 |
     | cat     | f    |        1 |
     | cat     | m    |        1 |
     | dog     | f    |        1 |
     | dog     | m    |        2 |
     | hamster | f    |        1 |
     | snake   | m    |        1 |
     +---------+------+----------+

You need not retrieve an entire table when you use `COUNT()'. For
example, the previous query, when performed just on dogs and cats, looks
like this:

     mysql> SELECT species, sex, COUNT(*) FROM pet
         -> WHERE species = 'dog' OR species = 'cat'
         -> GROUP BY species, sex;
     +---------+------+----------+
     | species | sex  | COUNT(*) |
     +---------+------+----------+
     | cat     | f    |        1 |
     | cat     | m    |        1 |
     | dog     | f    |        1 |
     | dog     | m    |        2 |
     +---------+------+----------+

Or, if you wanted the number of animals per sex only for animals whose
sex is known:

     mysql> SELECT species, sex, COUNT(*) FROM pet
         -> WHERE sex IS NOT NULL
         -> GROUP BY species, sex;
     +---------+------+----------+
     | species | sex  | COUNT(*) |
     +---------+------+----------+
     | bird    | f    |        1 |
     | cat     | f    |        1 |
     | cat     | m    |        1 |
     | dog     | f    |        1 |
     | dog     | m    |        2 |
     | hamster | f    |        1 |
     | snake   | m    |        1 |
     +---------+------+----------+

If you name columns to select in addition to the `COUNT()' value, a
`GROUP BY' clause should be present that names those same columns.
Otherwise, the following occurs:

   * If the `ONLY_FULL_GROUP_BY' SQL mode is enabled, an error occurs:

          mysql> SET sql_mode = 'ONLY_FULL_GROUP_BY';
          Query OK, 0 rows affected (0.00 sec)

          mysql> SELECT owner, COUNT(*) FROM pet;
          ERROR 1140 (42000): Mixing of GROUP columns (MIN(),MAX(),COUNT()...)
          with no GROUP columns is illegal if there is no GROUP BY clause

   * If `ONLY_FULL_GROUP_BY' is not enabled, the query is processed by
     treating all rows as a single group, but the value selected for
     each named column is indeterminate. The server is free to select
     the value from any row:

          mysql> SET sql_mode = '';
          Query OK, 0 rows affected (0.00 sec)

          mysql> SELECT owner, COUNT(*) FROM pet;
          +--------+----------+
          | owner  | COUNT(*) |
          +--------+----------+
          | Harold |        8 |
          +--------+----------+
          1 row in set (0.00 sec)

See also *Note group-by-hidden-columns::.


File: manual.info,  Node: multiple-tables,  Prev: counting-rows,  Up: retrieving-data

4.3.4.9 Using More Than one Table
.................................

The `pet' table keeps track of which pets you have. If you want to
record other information about them, such as events in their lives like
visits to the vet or when litters are born, you need another table.
What should this table look like? It needs to contain the following
information:

   * The pet name so that you know which animal each event pertains to.

   * A date so that you know when the event occurred.

   * A field to describe the event.

   * An event type field, if you want to be able to categorize events.

Given these considerations, the *Note `CREATE TABLE': create-table.
statement for the `event' table might look like this:

     mysql> CREATE TABLE event (name VARCHAR(20), date DATE,
         -> type VARCHAR(15), remark VARCHAR(255));

As with the `pet' table, it is easiest to load the initial records by
creating a tab-delimited text file containing the following information.

name        date        type        remark
Fluffy      1995-05-15  litter      4 kittens, 3 female, 1
                                    male
Buffy       1993-06-23  litter      5 puppies, 2 female, 3
                                    male
Buffy       1994-06-19  litter      3 puppies, 3 female
Chirpy      1999-03-21  vet         needed beak straightened
Slim        1997-08-03  vet         broken rib
Bowser      1991-10-12  kennel      
Fang        1991-10-12  kennel      
Fang        1998-08-28  birthday    Gave him a new chew toy
Claws       1998-03-17  birthday    Gave him a new flea
                                    collar
Whistler    1998-12-09  birthday    First birthday

Load the records like this:

     mysql> LOAD DATA LOCAL INFILE 'event.txt' INTO TABLE event;

Based on what you have learned from the queries that you have run on
the `pet' table, you should be able to perform retrievals on the
records in the `event' table; the principles are the same.  But when is
the `event' table by itself insufficient to answer questions you might
ask?

Suppose that you want to find out the ages at which each pet had its
litters. We saw earlier how to calculate ages from two dates. The
litter date of the mother is in the `event' table, but to calculate her
age on that date you need her birth date, which is stored in the `pet'
table. This means the query requires both tables:

     mysql> SELECT pet.name,
         -> (YEAR(date)-YEAR(birth)) - (RIGHT(date,5)<RIGHT(birth,5)) AS age,
         -> remark
         -> FROM pet INNER JOIN event
         ->   ON pet.name = event.name
         -> WHERE event.type = 'litter';
     +--------+------+-----------------------------+
     | name   | age  | remark                      |
     +--------+------+-----------------------------+
     | Fluffy |    2 | 4 kittens, 3 female, 1 male |
     | Buffy  |    4 | 5 puppies, 2 female, 3 male |
     | Buffy  |    5 | 3 puppies, 3 female         |
     +--------+------+-----------------------------+

There are several things to note about this query:

   * The `FROM' clause joins two tables because the query needs to pull
     information from both of them.

   * When combining (joining) information from multiple tables, you
     need to specify how records in one table can be matched to records
     in the other. This is easy because they both have a `name' column.
     The query uses `ON' clause to match up records in the two tables
     based on the `name' values.

     The query uses an `INNER JOIN' to combine the tables. An `INNER
     JOIN' permits rows from either table to appear in the result if
     and only if both tables meet the conditions specified in the `ON'
     clause. In this example, the `ON' clause specifies that the `name'
     column in the `pet' table must match the `name' column in the
     `event' table. If a name appears in one table but not the other,
     the row will not appear in the result because the condition in the
     `ON' clause fails.

   * Because the `name' column occurs in both tables, you must be
     specific about which table you mean when referring to the column.
     This is done by prepending the table name to the column name.

You need not have two different tables to perform a join.  Sometimes it
is useful to join a table to itself, if you want to compare records in
a table to other records in that same table. For example, to find
breeding pairs among your pets, you can join the `pet' table with
itself to produce candidate pairs of males and females of like species:

     mysql> SELECT p1.name, p1.sex, p2.name, p2.sex, p1.species
         -> FROM pet AS p1 INNER JOIN pet AS p2
         ->   ON p1.species = p2.species AND p1.sex = 'f' AND p2.sex = 'm';
     +--------+------+--------+------+---------+
     | name   | sex  | name   | sex  | species |
     +--------+------+--------+------+---------+
     | Fluffy | f    | Claws  | m    | cat     |
     | Buffy  | f    | Fang   | m    | dog     |
     | Buffy  | f    | Bowser | m    | dog     |
     +--------+------+--------+------+---------+

In this query, we specify aliases for the table name to refer to the
columns and keep straight which instance of the table each column
reference is associated with.


File: manual.info,  Node: getting-information,  Next: batch-mode,  Prev: database-use,  Up: tutorial

4.4 Getting Information About Databases and Tables
==================================================

What if you forget the name of a database or table, or what the
structure of a given table is (for example, what its columns are
called)? MySQL addresses this problem through several statements that
provide information about the databases and tables it supports.

You have previously seen *Note `SHOW DATABASES': show-databases, which
lists the databases managed by the server. To find out which database
is currently selected, use the `DATABASE()' function:

     mysql> SELECT DATABASE();
     +------------+
     | DATABASE() |
     +------------+
     | menagerie  |
     +------------+

If you have not yet selected any database, the result is `NULL'.

To find out what tables the default database contains (for example,
when you are not sure about the name of a table), use this command:

     mysql> SHOW TABLES;
     +---------------------+
     | Tables_in_menagerie |
     +---------------------+
     | event               |
     | pet                 |
     +---------------------+

The name of the column in the output produced by this statement is
always `Tables_in_DB_NAME', where DB_NAME is the name of the database.
See *Note show-tables::, for more information.

If you want to find out about the structure of a table, the *Note
`DESCRIBE': describe. statement is useful; it displays information
about each of a table's columns:

     mysql> DESCRIBE pet;
     +---------+-------------+------+-----+---------+-------+
     | Field   | Type        | Null | Key | Default | Extra |
     +---------+-------------+------+-----+---------+-------+
     | name    | varchar(20) | YES  |     | NULL    |       |
     | owner   | varchar(20) | YES  |     | NULL    |       |
     | species | varchar(20) | YES  |     | NULL    |       |
     | sex     | char(1)     | YES  |     | NULL    |       |
     | birth   | date        | YES  |     | NULL    |       |
     | death   | date        | YES  |     | NULL    |       |
     +---------+-------------+------+-----+---------+-------+

`Field' indicates the column name, `Type' is the data type for the
column, `NULL' indicates whether the column can contain `NULL' values,
`Key' indicates whether the column is indexed, and `Default' specifies
the column's default value. `Extra' displays special information about
columns: If a column was created with the `AUTO_INCREMENT' option, the
value will be `auto_increment' rather than empty.

`DESC' is a short form of *Note `DESCRIBE': describe. See *Note
describe::, for more information.

You can obtain the *Note `CREATE TABLE': create-table.  statement
necessary to create an existing table using the *Note `SHOW CREATE
TABLE': show-create-table. statement. See *Note show-create-table::.

If you have indexes on a table, `SHOW INDEX FROM TBL_NAME' produces
information about them. See *Note show-index::, for more about this
statement.


File: manual.info,  Node: batch-mode,  Next: examples,  Prev: getting-information,  Up: tutorial

4.5 Using `mysql' in Batch Mode
===============================

In the previous sections, you used *Note `mysql': mysql.  interactively
to enter queries and view the results. You can also run *Note `mysql':
mysql. in batch mode. To do this, put the commands you want to run in a
file, then tell *Note `mysql': mysql. to read its input from the file:

     shell> mysql < BATCH-FILE

If you are running *Note `mysql': mysql. under Windows and have some
special characters in the file that cause problems, you can do this:

     C:\> mysql -e "source BATCH-FILE"

If you need to specify connection parameters on the command line, the
command might look like this:

     shell> mysql -h HOST -u USER -p < BATCH-FILE
     Enter password: ********

When you use *Note `mysql': mysql. this way, you are creating a script
file, then executing the script.

If you want the script to continue even if some of the statements in it
produce errors, you should use the `--force' command-line option.

Why use a script? Here are a few reasons:

   * If you run a query repeatedly (say, every day or every week),
     making it a script enables you to avoid retyping it each time you
     execute it.

   * You can generate new queries from existing ones that are similar
     by copying and editing script files.

   * Batch mode can also be useful while you're developing a query,
     particularly for multiple-line commands or multiple-statement
     sequences of commands. If you make a mistake, you don't have to
     retype everything. Just edit your script to correct the error,
     then tell *Note `mysql': mysql. to execute it again.

   * If you have a query that produces a lot of output, you can run the
     output through a pager rather than watching it scroll off the top
     of your screen:

          shell> mysql < BATCH-FILE | more

   * You can catch the output in a file for further processing:

          shell> mysql < BATCH-FILE > mysql.out

   * You can distribute your script to other people so that they can
     also run the commands.

   * Some situations do not allow for interactive use, for example,
     when you run a query from a `cron' job. In this case, you must use
     batch mode.

The default output format is different (more concise) when you run
*Note `mysql': mysql. in batch mode than when you use it interactively.
For example, the output of `SELECT DISTINCT species FROM pet' looks
like this when *Note `mysql': mysql. is run interactively:

     +---------+
     | species |
     +---------+
     | bird    |
     | cat     |
     | dog     |
     | hamster |
     | snake   |
     +---------+

In batch mode, the output looks like this instead:

     species
     bird
     cat
     dog
     hamster
     snake

If you want to get the interactive output format in batch mode, use
`mysql -t'. To echo to the output the commands that are executed, use
`mysql -vvv'.

You can also use scripts from the *Note `mysql': mysql. prompt by using
the `source' command or `\.' command:

     mysql> source FILENAME;
     mysql> \. FILENAME

See *Note batch-commands::, for more information.


File: manual.info,  Node: examples,  Next: apache,  Prev: batch-mode,  Up: tutorial

4.6 Examples of Common Queries
==============================

* Menu:

* example-maximum-column::       The Maximum Value for a Column
* example-maximum-row::          The Row Holding the Maximum of a Certain Column
* example-maximum-column-group::  Maximum of Column per Group
* example-maximum-column-group-row::  The Rows Holding the Group-wise Maximum of a Certain Column
* example-user-variables::       Using User-Defined Variables
* example-foreign-keys::         Using Foreign Keys
* searching-on-two-keys::        Searching on Two Keys
* calculating-days::             Calculating Visits Per Day
* example-auto-increment::       Using `AUTO_INCREMENT'

Here are examples of how to solve some common problems with MySQL.

Some of the examples use the table `shop' to hold the price of each
article (item number) for certain traders (dealers). Supposing that
each trader has a single fixed price per article, then (`article',
`dealer') is a primary key for the records.

Start the command-line tool *Note `mysql': mysql. and select a database:

     shell> mysql YOUR-DATABASE-NAME

(In most MySQL installations, you can use the database named `test').

You can create and populate the example table with these statements:

     CREATE TABLE shop (
         article INT(4) UNSIGNED ZEROFILL DEFAULT '0000' NOT NULL,
         dealer  CHAR(20)                 DEFAULT ''     NOT NULL,
         price   DOUBLE(16,2)             DEFAULT '0.00' NOT NULL,
         PRIMARY KEY(article, dealer));
     INSERT INTO shop VALUES
         (1,'A',3.45),(1,'B',3.99),(2,'A',10.99),(3,'B',1.45),
         (3,'C',1.69),(3,'D',1.25),(4,'D',19.95);

After issuing the statements, the table should have the following
contents:

     SELECT * FROM shop;

     +---------+--------+-------+
     | article | dealer | price |
     +---------+--------+-------+
     |    0001 | A      |  3.45 |
     |    0001 | B      |  3.99 |
     |    0002 | A      | 10.99 |
     |    0003 | B      |  1.45 |
     |    0003 | C      |  1.69 |
     |    0003 | D      |  1.25 |
     |    0004 | D      | 19.95 |
     +---------+--------+-------+


File: manual.info,  Node: example-maximum-column,  Next: example-maximum-row,  Prev: examples,  Up: examples

4.6.1 The Maximum Value for a Column
------------------------------------

`What is the highest item number?'

     SELECT MAX(article) AS article FROM shop;

     +---------+
     | article |
     +---------+
     |       4 |
     +---------+


File: manual.info,  Node: example-maximum-row,  Next: example-maximum-column-group,  Prev: example-maximum-column,  Up: examples

4.6.2 The Row Holding the Maximum of a Certain Column
-----------------------------------------------------

_Task: Find the number, dealer, and price of the most expensive
article._

This is easily done with a subquery:

     SELECT article, dealer, price
     FROM   shop
     WHERE  price=(SELECT MAX(price) FROM shop);

     +---------+--------+-------+
     | article | dealer | price |
     +---------+--------+-------+
     |    0004 | D      | 19.95 |
     +---------+--------+-------+

Other solutions are to use a `LEFT JOIN' or to sort all rows descending
by price and get only the first row using the MySQL-specific `LIMIT'
clause:

     SELECT s1.article, s1.dealer, s1.price
     FROM shop s1
     LEFT JOIN shop s2 ON s1.price < s2.price
     WHERE s2.article IS NULL;

     SELECT article, dealer, price
     FROM shop
     ORDER BY price DESC
     LIMIT 1;

*Note*:

If there were several most expensive articles, each with a price of
19.95, the `LIMIT' solution would show only one of them.


File: manual.info,  Node: example-maximum-column-group,  Next: example-maximum-column-group-row,  Prev: example-maximum-row,  Up: examples

4.6.3 Maximum of Column per Group
---------------------------------

_Task: Find the highest price per article._

     SELECT article, MAX(price) AS price
     FROM   shop
     GROUP BY article;

     +---------+-------+
     | article | price |
     +---------+-------+
     |    0001 |  3.99 |
     |    0002 | 10.99 |
     |    0003 |  1.69 |
     |    0004 | 19.95 |
     +---------+-------+


File: manual.info,  Node: example-maximum-column-group-row,  Next: example-user-variables,  Prev: example-maximum-column-group,  Up: examples

4.6.4 The Rows Holding the Group-wise Maximum of a Certain Column
-----------------------------------------------------------------

_Task: For each article, find the dealer or dealers with the most
expensive price._

This problem can be solved with a subquery like this one:

     SELECT article, dealer, price
     FROM   shop s1
     WHERE  price=(SELECT MAX(s2.price)
                   FROM shop s2
                   WHERE s1.article = s2.article);

     +---------+--------+-------+
     | article | dealer | price |
     +---------+--------+-------+
     |    0001 | B      |  3.99 |
     |    0002 | A      | 10.99 |
     |    0003 | C      |  1.69 |
     |    0004 | D      | 19.95 |
     +---------+--------+-------+

The preceding example uses a correlated subquery, which can be
inefficient (see *Note correlated-subqueries::). Other possibilities
for solving the problem are to use an uncorrelated subquery in the
`FROM' clause or a `LEFT JOIN':

     SELECT s1.article, dealer, s1.price
     FROM shop s1
     JOIN (
       SELECT article, MAX(price) AS price
       FROM shop
       GROUP BY article) AS s2
       ON s1.article = s2.article AND s1.price = s2.price;

     SELECT s1.article, s1.dealer, s1.price
     FROM shop s1
     LEFT JOIN shop s2 ON s1.article = s2.article AND s1.price < s2.price
     WHERE s2.article IS NULL;

The `LEFT JOIN' works on the basis that when `s1.price' is at its
maximum value, there is no `s2.price' with a greater value and the `s2'
rows values will be `NULL'. See *Note join::.


File: manual.info,  Node: example-user-variables,  Next: example-foreign-keys,  Prev: example-maximum-column-group-row,  Up: examples

4.6.5 Using User-Defined Variables
----------------------------------

You can employ MySQL user variables to remember results without having
to store them in temporary variables in the client. (See *Note
user-variables::.)

For example, to find the articles with the highest and lowest price you
can do this:

     mysql> SELECT @min_price:=MIN(price),@max_price:=MAX(price) FROM shop;
     mysql> SELECT * FROM shop WHERE price=@min_price OR price=@max_price;
     +---------+--------+-------+
     | article | dealer | price |
     +---------+--------+-------+
     |    0003 | D      |  1.25 |
     |    0004 | D      | 19.95 |
     +---------+--------+-------+

*Note*:

It is also possible to store the name of a database object such as a
table or a column in a user variable and then to use this variable in
an SQL statement; however, this requires the use of a prepared
statement. See *Note sql-syntax-prepared-statements::, for more
information.


File: manual.info,  Node: example-foreign-keys,  Next: searching-on-two-keys,  Prev: example-user-variables,  Up: examples

4.6.6 Using Foreign Keys
------------------------

In MySQL, `InnoDB' tables support checking of foreign key constraints.
See *Note innodb-storage-engine::, and *Note ansi-diff-foreign-keys::.

A foreign key constraint is not required merely to join two tables. For
storage engines other than `InnoDB', it is possible when defining a
column to use a `REFERENCES TBL_NAME(COL_NAME)' clause, which has no
actual effect, and _serves only as a memo or comment to you that the
column which you are currently defining is intended to refer to a
column in another table_. It is extremely important to realize when
using this syntax that:

   * MySQL does not perform any sort of `CHECK' to make sure that
     COL_NAME actually exists in TBL_NAME (or even that TBL_NAME itself
     exists).

   * MySQL does not perform any sort of action on TBL_NAME such as
     deleting rows in response to actions taken on rows in the table
     which you are defining; in other words, this syntax induces no `ON
     DELETE' or `ON UPDATE' behavior whatsoever. (Although you can
     write an `ON DELETE' or `ON UPDATE' clause as part of the
     `REFERENCES' clause, it is also ignored.)

   * This syntax creates a _column_; it does *not* create any sort of
     index or key.

You can use a column so created as a join column, as shown here:

     CREATE TABLE person (
         id SMALLINT UNSIGNED NOT NULL AUTO_INCREMENT,
         name CHAR(60) NOT NULL,
         PRIMARY KEY (id)
     );

     CREATE TABLE shirt (
         id SMALLINT UNSIGNED NOT NULL AUTO_INCREMENT,
         style ENUM('t-shirt', 'polo', 'dress') NOT NULL,
         color ENUM('red', 'blue', 'orange', 'white', 'black') NOT NULL,
         owner SMALLINT UNSIGNED NOT NULL REFERENCES person(id),
         PRIMARY KEY (id)
     );

     INSERT INTO person VALUES (NULL, 'Antonio Paz');

     SELECT @last := LAST_INSERT_ID();

     INSERT INTO shirt VALUES
     (NULL, 'polo', 'blue', @last),
     (NULL, 'dress', 'white', @last),
     (NULL, 't-shirt', 'blue', @last);

     INSERT INTO person VALUES (NULL, 'Lilliana Angelovska');

     SELECT @last := LAST_INSERT_ID();

     INSERT INTO shirt VALUES
     (NULL, 'dress', 'orange', @last),
     (NULL, 'polo', 'red', @last),
     (NULL, 'dress', 'blue', @last),
     (NULL, 't-shirt', 'white', @last);

     SELECT * FROM person;
     +----+---------------------+
     | id | name                |
     +----+---------------------+
     |  1 | Antonio Paz         |
     |  2 | Lilliana Angelovska |
     +----+---------------------+

     SELECT * FROM shirt;
     +----+---------+--------+-------+
     | id | style   | color  | owner |
     +----+---------+--------+-------+
     |  1 | polo    | blue   |     1 |
     |  2 | dress   | white  |     1 |
     |  3 | t-shirt | blue   |     1 |
     |  4 | dress   | orange |     2 |
     |  5 | polo    | red    |     2 |
     |  6 | dress   | blue   |     2 |
     |  7 | t-shirt | white  |     2 |
     +----+---------+--------+-------+

     SELECT s.* FROM person p INNER JOIN shirt s
        ON s.owner = p.id
      WHERE p.name LIKE 'Lilliana%'
        AND s.color <> 'white';

     +----+-------+--------+-------+
     | id | style | color  | owner |
     +----+-------+--------+-------+
     |  4 | dress | orange |     2 |
     |  5 | polo  | red    |     2 |
     |  6 | dress | blue   |     2 |
     +----+-------+--------+-------+

When used in this fashion, the `REFERENCES' clause is not displayed in
the output of *Note `SHOW CREATE TABLE': show-create-table. or *Note
`DESCRIBE': describe.:

     SHOW CREATE TABLE shirt\G
     *************************** 1. row ***************************
     Table: shirt
     Create Table: CREATE TABLE `shirt` (
     `id` smallint(5) unsigned NOT NULL auto_increment,
     `style` enum('t-shirt','polo','dress') NOT NULL,
     `color` enum('red','blue','orange','white','black') NOT NULL,
     `owner` smallint(5) unsigned NOT NULL,
     PRIMARY KEY  (`id`)
     ) ENGINE=MyISAM DEFAULT CHARSET=latin1

The use of `REFERENCES' in this way as a comment or `reminder' in a
column definition works with both `MyISAM' and `BerkeleyDB' tables.


File: manual.info,  Node: searching-on-two-keys,  Next: calculating-days,  Prev: example-foreign-keys,  Up: examples

4.6.7 Searching on Two Keys
---------------------------

An `OR' using a single key is well optimized, as is the handling of
`AND'.

The one tricky case is that of searching on two different keys combined
with `OR':

     SELECT field1_index, field2_index FROM test_table
     WHERE field1_index = '1' OR  field2_index = '1'

This case is optimized from MySQL 5.0.0. See *Note
index-merge-optimization::.

You can also solve the problem efficiently by using a *Note `UNION':
union. that combines the output of two separate *Note `SELECT': select.
statements.  See *Note union::.

Each *Note `SELECT': select. searches only one key and can be optimized:

     SELECT field1_index, field2_index
         FROM test_table WHERE field1_index = '1'
     UNION
     SELECT field1_index, field2_index
         FROM test_table WHERE field2_index = '1';


File: manual.info,  Node: calculating-days,  Next: example-auto-increment,  Prev: searching-on-two-keys,  Up: examples

4.6.8 Calculating Visits Per Day
--------------------------------

The following example shows how you can use the bit group functions to
calculate the number of days per month a user has visited a Web page.

     CREATE TABLE t1 (year YEAR(4), month INT(2) UNSIGNED ZEROFILL,
                  day INT(2) UNSIGNED ZEROFILL);
     INSERT INTO t1 VALUES(2000,1,1),(2000,1,20),(2000,1,30),(2000,2,2),
                 (2000,2,23),(2000,2,23);

The example table contains year-month-day values representing visits by
users to the page. To determine how many different days in each month
these visits occur, use this query:

     SELECT year,month,BIT_COUNT(BIT_OR(1<<day)) AS days FROM t1
            GROUP BY year,month;

Which returns:

     +------+-------+------+
     | year | month | days |
     +------+-------+------+
     | 2000 |    01 |    3 |
     | 2000 |    02 |    2 |
     +------+-------+------+

The query calculates how many different days appear in the table for
each year/month combination, with automatic removal of duplicate
entries.


File: manual.info,  Node: example-auto-increment,  Prev: calculating-days,  Up: examples

4.6.9 Using `AUTO_INCREMENT'
----------------------------

The `AUTO_INCREMENT' attribute can be used to generate a unique
identity for new rows:

     CREATE TABLE animals (
          id MEDIUMINT NOT NULL AUTO_INCREMENT,
          name CHAR(30) NOT NULL,
          PRIMARY KEY (id)
     ) ENGINE=MyISAM;

     INSERT INTO animals (name) VALUES
         ('dog'),('cat'),('penguin'),
         ('lax'),('whale'),('ostrich');

     SELECT * FROM animals;

Which returns:

     +----+---------+
     | id | name    |
     +----+---------+
     |  1 | dog     |
     |  2 | cat     |
     |  3 | penguin |
     |  4 | lax     |
     |  5 | whale   |
     |  6 | ostrich |
     +----+---------+

No value was specified for the `AUTO_INCREMENT' column, so MySQL
assigned sequence numbers automatically. You can also explicitly assign
`NULL' or 0 to the column to generate sequence numbers.

You can retrieve the most recent `AUTO_INCREMENT' value with the
`LAST_INSERT_ID()' SQL function or the *Note `mysql_insert_id()':
mysql-insert-id. C API function. These functions are
connection-specific, so their return values are not affected by another
connection which is also performing inserts.

Use a large enough integer data type for the `AUTO_INCREMENT' column to
hold the maximum sequence value you will need. When the column reaches
the upper limit of the data type, the next attempt to generate a
sequence number fails. For example, if you use *Note `TINYINT':
numeric-types, the maximum permissible sequence number is 127. For
*Note `TINYINT UNSIGNED': numeric-types, the maximum is 255.

*Note*:

For a multiple-row insert, `LAST_INSERT_ID()' and *Note
`mysql_insert_id()': mysql-insert-id. actually return the
`AUTO_INCREMENT' key from the _first_ of the inserted rows. This enables
multiple-row inserts to be reproduced correctly on other servers in a
replication setup.

For `MyISAM' and `BDB' tables you can specify `AUTO_INCREMENT' on a
secondary column in a multiple-column index. In this case, the generated
value for the `AUTO_INCREMENT' column is calculated as
`MAX(AUTO_INCREMENT_COLUMN) + 1 WHERE prefix=GIVEN-PREFIX'. This is
useful when you want to put data into ordered groups.

     CREATE TABLE animals (
         grp ENUM('fish','mammal','bird') NOT NULL,
         id MEDIUMINT NOT NULL AUTO_INCREMENT,
         name CHAR(30) NOT NULL,
         PRIMARY KEY (grp,id)
     ) ENGINE=MyISAM;

     INSERT INTO animals (grp,name) VALUES
         ('mammal','dog'),('mammal','cat'),
         ('bird','penguin'),('fish','lax'),('mammal','whale'),
         ('bird','ostrich');

     SELECT * FROM animals ORDER BY grp,id;

Which returns:

     +--------+----+---------+
     | grp    | id | name    |
     +--------+----+---------+
     | fish   |  1 | lax     |
     | mammal |  1 | dog     |
     | mammal |  2 | cat     |
     | mammal |  3 | whale   |
     | bird   |  1 | penguin |
     | bird   |  2 | ostrich |
     +--------+----+---------+

In this case (when the `AUTO_INCREMENT' column is part of a
multiple-column index), `AUTO_INCREMENT' values are reused if you
delete the row with the biggest `AUTO_INCREMENT' value in any group.
This happens even for `MyISAM' tables, for which `AUTO_INCREMENT'
values normally are not reused.

If the `AUTO_INCREMENT' column is part of multiple indexes, MySQL will
generate sequence values using the index that begins with the
`AUTO_INCREMENT' column, if there is one. For example, if the `animals'
table contained indexes `PRIMARY KEY (grp, id)' and `INDEX (id)', MySQL
would ignore the `PRIMARY KEY' for generating sequence values. As a
result, the table would contain a single sequence, not a sequence per
`grp' value.

To start with an `AUTO_INCREMENT' value other than 1, you can set that
value with *Note `CREATE TABLE': create-table. or *Note `ALTER TABLE':
alter-table, like this:

     mysql> ALTER TABLE tbl AUTO_INCREMENT = 100;

More information about `AUTO_INCREMENT' is available here:

   * How to assign the `AUTO_INCREMENT' attribute to a column: *Note
     create-table::, and *Note alter-table::.

   * How `AUTO_INCREMENT' behaves depending on the
     `NO_AUTO_VALUE_ON_ZERO' SQL mode: *Note server-sql-mode::.

   * How to use the `LAST_INSERT_ID()' function to find the row that
     contains the most recent `AUTO_INCREMENT' value: *Note
     information-functions::.

   * Setting the `AUTO_INCREMENT' value to be used: *Note
     server-system-variables::.

   * `AUTO_INCREMENT' and replication: *Note
     replication-features-auto-increment::.

   * Server-system variables related to `AUTO_INCREMENT'
     (`auto_increment_increment' and `auto_increment_offset') that can
     be used for replication: *Note server-system-variables::.


File: manual.info,  Node: apache,  Prev: examples,  Up: tutorial

4.7 Using MySQL with Apache
===========================

There are programs that let you authenticate your users from a MySQL
database and also let you write your log files into a MySQL table.

You can change the Apache logging format to be easily readable by MySQL
by putting the following into the Apache configuration file:

     LogFormat \
             "\"%h\",%{%Y%m%d%H%M%S}t,%>s,\"%b\",\"%{Content-Type}o\",  \
             \"%U\",\"%{Referer}i\",\"%{User-Agent}i\""

To load a log file in that format into MySQL, you can use a statement
something like this:

     LOAD DATA INFILE '/LOCAL/ACCESS_LOG' INTO TABLE TBL_NAME
     FIELDS TERMINATED BY ',' OPTIONALLY ENCLOSED BY '"' ESCAPED BY '\\'

The named table should be created to have columns that correspond to
those that the `LogFormat' line writes to the log file.


File: manual.info,  Node: programs,  Next: server-administration,  Prev: tutorial,  Up: Top

5 MySQL Programs
****************

* Menu:

* programs-overview::            Overview of MySQL Programs
* programs-using::               Using MySQL Programs
* programs-server::              MySQL Server and Server-Startup Programs
* programs-installation::        MySQL Installation-Related Programs
* programs-client::              MySQL Client Programs
* programs-admin-utils::         MySQL Administrative and Utility Programs
* programs-development::         MySQL Program Development Utilities
* programs-miscellaneous::       Miscellaneous Programs

This chapter provides a brief overview of the MySQL command-line
programs provided by Oracle Corporation. It also discusses the general
syntax for specifying options when you run these programs.  Most
programs have options that are specific to their own operation, but the
option syntax is similar for all of them. Finally, the chapter provides
more detailed descriptions of individual programs, including which
options they recognize.


File: manual.info,  Node: programs-overview,  Next: programs-using,  Prev: programs,  Up: programs

5.1 Overview of MySQL Programs
==============================

There are many different programs in a MySQL installation. This section
provides a brief overview of them. Later sections provide a more
detailed description of each one, with the exception of MySQL Cluster
programs. Each program's description indicates its invocation syntax
and the options that it supports.  *Note mysql-cluster::, describes
programs specific to MySQL Cluster.

Most MySQL distributions include all of these programs, except for
those programs that are platform-specific. (For example, the server
startup scripts are not used on Windows.) The exception is that RPM
distributions are more specialized. There is one RPM for the server,
another for client programs, and so forth. If you appear to be missing
one or more programs, see *Note installing::, for information on types
of distributions and what they contain. It may be that you have a
distribution that does not include all programs and you need to install
an additional package.

Each MySQL program takes many different options. Most programs provide
a `--help' option that you can use to get a description of the
program's different options. For example, try *Note `mysql --help':
mysql.

You can override default option values for MySQL programs by specifying
options on the command line or in an option file. See *Note
programs-using::, for general information on invoking programs and
specifying program options.

The MySQL server, *Note `mysqld': mysqld, is the main program that does
most of the work in a MySQL installation. The server is accompanied by
several related scripts that assist you in starting and stopping the
server:

   * *Note `mysqld': mysqld.

     The SQL daemon (that is, the MySQL server). To use client
     programs, *Note `mysqld': mysqld. must be running, because clients
     gain access to databases by connecting to the server.  See *Note
     mysqld::.

   * *Note `mysqld_safe': mysqld-safe.

     A server startup script. *Note `mysqld_safe': mysqld-safe.
     attempts to start *Note `mysqld': mysqld. See *Note mysqld-safe::.

   * *Note `mysql.server': mysql-server.

     A server startup script. This script is used on systems that use
     System V-style run directories containing scripts that start
     system services for particular run levels. It invokes *Note
     `mysqld_safe': mysqld-safe. to start the MySQL server. See *Note
     mysql-server::.

   * *Note `mysqld_multi': mysqld-multi.

     A server startup script that can start or stop multiple servers
     installed on the system. See *Note mysqld-multi::. As of MySQL
     5.0.3 (Unix-like systems) or 5.0.13 (Windows), an alternative to
     *Note `mysqld_multi': mysqld-multi. is `mysqlmanager', the MySQL
     Instance Manager.  See *Note instance-manager::.

There are several programs that perform setup operations during MySQL
installation or upgrading:

   * *Note `comp_err': comp-err.

     This program is used during the MySQL build/installation process.
     It compiles error message files from the error source files. See
     *Note comp-err::.

   * `make_binary_distribution'

     This program makes a binary release of a compiled MySQL. This
     could be sent by FTP to `/pub/mysql/upload/' on `ftp.mysql.com'
     for the convenience of other MySQL users.

   * *Note `make_win_bin_dist': make-win-bin-dist.

     This program is used on Windows. It packages a MySQL distribution
     for installation after the source distribution has been built. See
     *Note make-win-bin-dist::.

   * *Note `mysql_fix_privilege_tables': mysql-fix-privilege-tables.

     This program is used after a MySQL upgrade operation. It updates
     the grant tables with any changes that have been made in newer
     versions of MySQL. See *Note mysql-fix-privilege-tables::.

     Note: As of MySQL 5.0.19, this program has been superseded by
     *Note `mysql_upgrade': mysql-upgrade. and should no longer be used.

   * *Note `mysql_install_db': mysql-install-db.

     This script creates the MySQL database and initializes the grant
     tables with default privileges. It is usually executed only once,
     when first installing MySQL on a system. See *Note
     mysql-install-db::, *Note unix-postinstallation::, and *Note
     mysql-install-db::.

   * *Note `mysql_secure_installation': mysql-secure-installation.

     This program enables you to improve the security of your MySQL
     installation. SQL. See *Note mysql-secure-installation::.

   * *Note `mysql_tzinfo_to_sql': mysql-tzinfo-to-sql.

     This program loads the time zone tables in the `mysql' database
     using the contents of the host system _zoneinfo_ database (the set
     of files describing time zones). SQL. See *Note
     mysql-tzinfo-to-sql::.

   * *Note `mysql_upgrade': mysql-upgrade.

     This program is used after a MySQL upgrade operation. It checks
     tables for incompatibilities and repairs them if necessary, and
     updates the grant tables with any changes that have been made in
     newer versions of MySQL. See *Note mysql-upgrade::.

   * *Note `make_win_src_distribution': make-win-src-distribution.

     This program is used on Unix or Unix-like systems to create a
     MySQL source distribution that can be compiled on Windows. See
     *Note windows-sourcetree-build::, and *Note
     make-win-src-distribution::.

MySQL client programs:

   * *Note `mysql': mysql.

     The command-line tool for interactively entering SQL statements or
     executing them from a file in batch mode. See *Note mysql::.

   * *Note `mysqladmin': mysqladmin.

     A client that performs administrative operations, such as creating
     or dropping databases, reloading the grant tables, flushing tables
     to disk, and reopening log files.  *Note `mysqladmin': mysqladmin.
     can also be used to retrieve version, process, and status
     information from the server. See *Note mysqladmin::.

   * *Note `mysqlcheck': mysqlcheck.

     A table-maintenance client that checks, repairs, analyzes, and
     optimizes tables. See *Note mysqlcheck::.

   * *Note `mysqldump': mysqldump.

     A client that dumps a MySQL database into a file as SQL, text, or
     XML. See *Note mysqldump::.

   * *Note `mysqlimport': mysqlimport.

     A client that imports text files into their respective tables
     using *Note `LOAD DATA INFILE': load-data. See *Note mysqlimport::.

   * *Note `mysqlshow': mysqlshow.

     A client that displays information about databases, tables,
     columns, and indexes. See *Note mysqlshow::.

MySQL administrative and utility programs:

   * *Note `innochecksum': innochecksum.

     An offline `InnoDB' offline file checksum utility. See *Note
     innochecksum::.

   * *Note `myisam_ftdump': myisam-ftdump.

     A utility that displays information about full-text indexes in
     `MyISAM' tables. See *Note myisam-ftdump::.

   * *Note `myisamchk': myisamchk.

     A utility to describe, check, optimize, and repair `MyISAM'
     tables. See *Note myisamchk::.

   * *Note `myisamlog': myisamlog, `isamlog'

     A utility that processes the contents of a `MyISAM' log file. See
     *Note myisamlog::.

   * *Note `myisampack': myisampack.

     A utility that compresses `MyISAM' tables to produce smaller
     read-only tables. See *Note myisampack::.

   * *Note `mysqlaccess': mysqlaccess.

     A script that checks the access privileges for a host name, user
     name, and database combination. See *Note mysqlaccess::.

   * *Note `mysqlbinlog': mysqlbinlog.

     A utility for reading statements from a binary log. The log of
     executed statements contained in the binary log files can be used
     to help recover from a crash. See *Note mysqlbinlog::.

   * *Note `mysqldumpslow': mysqldumpslow.

     A utility to read and summarize the contents of a slow query log.
     See *Note mysqldumpslow::.

   * *Note `mysqlhotcopy': mysqlhotcopy.

     A utility that quickly makes backups of `MyISAM' tables while the
     server is running.  See *Note mysqlhotcopy::.

   * `mysqlmanager'

     The MySQL Instance Manager, a program for monitoring and managing
     MySQL servers. See *Note instance-manager::.

     *Important*:

     MySQL Instance Manager has been deprecated and is removed in MySQL
     5.4.

   * *Note `mysql_convert_table_format': mysql-convert-table-format.

     A utility that converts tables in a database to use a given
     storage engine. See *Note mysql-convert-table-format::.

   * *Note `mysql_explain_log': mysql-explain-log.

     A utility that analyzes queries in the MySQL query log using *Note
     `EXPLAIN': explain. See *Note mysql-explain-log::.

   * *Note `mysql_find_rows': mysql-find-rows.

     A utility that reads files containing SQL statements (such as
     update logs) and extracts statements that match a given regular
     expression. See *Note mysql-find-rows::.

   * *Note `mysql_fix_extensions': mysql-fix-extensions.

     A utility that converts the extensions for `MyISAM' table files to
     lowercase. This can be useful after transferring the files from a
     system with case-insensitive file names to a system with
     case-sensitive file names. See *Note mysql-fix-extensions::.

   * *Note `mysql_setpermission': mysql-setpermission.

     A utility for interactively setting permissions in the MySQL grant
     tables. See *Note mysql-setpermission::.

   * *Note `mysql_tableinfo': mysql-tableinfo.

     A utility that generates database metadata.  *Note
     mysql-tableinfo::.

   * *Note `mysql_waitpid': mysql-waitpid.

     A utility that kills the process with a given process ID. See
     *Note mysql-waitpid::.

   * *Note `mysql_zap': mysql-zap.

     A utility that kills processes that match a pattern. See *Note
     mysql-zap::.

MySQL program-development utilities:

   * *Note `msql2mysql': msql2mysql.

     A shell script that converts `mSQL' programs to MySQL. It doesn't
     handle every case, but it gives a good start when converting. See
     *Note msql2mysql::.

   * *Note `mysql_config': mysql-config.

     A shell script that produces the option values needed when
     compiling MySQL programs. See *Note mysql-config::.

   * *Note `my_print_defaults': my-print-defaults.

     A utility that shows which options are present in option groups of
     option files. See *Note my-print-defaults::.

   * *Note `resolve_stack_dump': resolve-stack-dump.

     A utility program that resolves a numeric stack trace dump to
     symbols. See *Note resolve-stack-dump::.

Miscellaneous utilities:

   * *Note `perror': perror.

     A utility that displays the meaning of system or MySQL error
     codes. See *Note perror::.

   * *Note `replace': replace-utility.

     A utility program that performs string replacement in the input
     text. See *Note replace-utility::.

   * *Note `resolveip': resolveip.

     A utility program that resolves a host name to an IP address or
     vice versa. See *Note resolveip::.

Oracle Corporation also provides several GUI tools for administering
and otherwise working with MySQL Server:

   * MySQL Workbench: This is the latest graphical tool for working
     with MySQL databases.

   * MySQL Administrator: This tool is used for administering MySQL
     servers, databases, tables, and user accounts.

   * MySQL Query Browser: This graphical tool is used for creating,
     executing, and optimizing queries on MySQL databases.

   * MySQL Migration Toolkit: This tool helps you migrate schemas and
     data from other relational database management systems for use
     with MySQL.

These GUI programs are available at `http://dev.mysql.com/downloads/'.
Each has its own manual that you can access at
`http://dev.mysql.com/doc/'.

MySQL client programs that communicate with the server using the MySQL
client/server library use the following environment variables.

Environment        Meaning
Variable           
`MYSQL_UNIX_PORT'  The default Unix socket file; used for connections to
                   `localhost'
`MYSQL_TCP_PORT'   The default port number; used for TCP/IP connections
`MYSQL_PWD'        The default password
`MYSQL_DEBUG'      Debug trace options when debugging
`TMPDIR'           The directory where temporary tables and files are
                   created

For a full list of environment variables used by MySQL programs, see
*Note environment-variables::.

Use of `MYSQL_PWD' is insecure. See *Note password-security-user::.


File: manual.info,  Node: programs-using,  Next: programs-server,  Prev: programs-overview,  Up: programs

5.2 Using MySQL Programs
========================

* Menu:

* invoking-programs::            Invoking MySQL Programs
* connecting::                   Connecting to the MySQL Server
* program-options::              Specifying Program Options
* setting-environment-variables::  Setting Environment Variables


File: manual.info,  Node: invoking-programs,  Next: connecting,  Prev: programs-using,  Up: programs-using

5.2.1 Invoking MySQL Programs
-----------------------------

To invoke a MySQL program from the command line (that is, from your
shell or command prompt), enter the program name followed by any
options or other arguments needed to instruct the program what you want
it to do. The following commands show some sample program invocations.
``shell>'' represents the prompt for your command interpreter; it is
not part of what you type. The particular prompt you see depends on your
command interpreter. Typical prompts are `$' for `sh' or `bash', `%'
for `csh' or `tcsh', and `C:\>' for the Windows `command.com' or
`cmd.exe' command interpreters.

     shell> mysql --user=root test
     shell> mysqladmin extended-status variables
     shell> mysqlshow --help
     shell> mysqldump -u root personnel

Arguments that begin with a single or double dash (``-'', ``--'')
specify program options.  Options typically indicate the type of
connection a program should make to the server or affect its
operational mode. Option syntax is described in *Note program-options::.

Nonoption arguments (arguments with no leading dash) provide additional
information to the program. For example, the *Note `mysql': mysql.
program interprets the first nonoption argument as a database name, so
the command `mysql --user=root test' indicates that you want to use the
`test' database.

Later sections that describe individual programs indicate which options
a program supports and describe the meaning of any additional nonoption
arguments.

Some options are common to a number of programs. The most frequently
used of these are the `--host' (or `-h'), `--user' (or `-u'), and
`--password' (or `-p') options that specify connection parameters.
They indicate the host where the MySQL server is running, and the user
name and password of your MySQL account. All MySQL client programs
understand these options; they enable you to specify which server to
connect to and the account to use on that server.  Other connection
options are `--port' (or `-P') to specify a TCP/IP port number and
`--socket' (or `-S') to specify a Unix socket file on Unix (or named
pipe name on Windows). For more information on options that specify
connection options, see *Note connecting::.

You may find it necessary to invoke MySQL programs using the path name
to the `bin' directory in which they are installed. This is likely to
be the case if you get a `program not found' error whenever you attempt
to run a MySQL program from any directory other than the `bin'
directory. To make it more convenient to use MySQL, you can add the
path name of the `bin' directory to your `PATH' environment variable
setting. That enables you to run a program by typing only its name, not
its entire path name. For example, if *Note `mysql': mysql. is
installed in `/usr/local/mysql/bin', you can run the program by
invoking it as *Note `mysql': mysql, and it is not necessary to invoke
it as `/usr/local/mysql/bin/mysql'.

Consult the documentation for your command interpreter for instructions
on setting your `PATH' variable. The syntax for setting environment
variables is interpreter-specific.  (Some information is given in *Note
setting-environment-variables::.) After modifying your `PATH' setting,
open a new console window on Windows or log in again on Unix so that
the setting goes into effect.


File: manual.info,  Node: connecting,  Next: program-options,  Prev: invoking-programs,  Up: programs-using

5.2.2 Connecting to the MySQL Server
------------------------------------

For a client program to be able to connect to the MySQL server, it must
use the proper connection parameters, such as the name of the host
where the server is running and the user name and password of your
MySQL account. Each connection parameter has a default value, but you
can override them as necessary using program options specified either
on the command line or in an option file.

The examples here use the *Note `mysql': mysql. client program, but the
principles apply to other clients such as *Note `mysqldump': mysqldump,
*Note `mysqladmin': mysqladmin, or *Note `mysqlshow': mysqlshow.

This command invokes *Note `mysql': mysql. without specifying any
connection parameters explicitly:

     shell> mysql

Because there are no parameter options, the default values apply:

   * The default host name is `localhost'. On Unix, this has a special
     meaning, as described later.

   * The default user name is `ODBC' on Windows or your Unix login name
     on Unix.

   * No password is sent if neither `-p' nor `--password' is given.

   * For *Note `mysql': mysql, the first nonoption argument is taken as
     the name of the default database. If there is no such option,
     *Note `mysql': mysql. does not select a default database.

To specify the host name and user name explicitly, as well as a
password, supply appropriate options on the command line:

     shell> mysql --host=localhost --user=myname --password=mypass mydb
     shell> mysql -h localhost -u myname -pmypass mydb

For password options, the password value is optional:

   * If you use a `-p' or `--password' option and specify the password
     value, there must be _no space_ between `-p' or `--password=' and
     the password following it.

   * If you use a `-p' or `--password' option but do not specify the
     password value, the client program prompts you to enter the
     password. The password is not displayed as you enter it. This is
     more secure than giving the password on the command line. Other
     users on your system may be able to see a password specified on
     the command line by executing a command such as `ps auxw'. See
     *Note password-security-user::.

As just mentioned, including the password value on the command line can
be a security risk. To avoid this problem, specify the `--password' or
`-p' option without any following password value:

     shell> mysql --host=localhost --user=myname --password mydb
     shell> mysql -h localhost -u myname -p mydb

When the password option has no password value, the client program
prints a prompt and waits for you to enter the password. (In these
examples, `mydb' is _not_ interpreted as a password because it is
separated from the preceding password option by a space.)

On some systems, the library routine that MySQL uses to prompt for a
password automatically limits the password to eight characters.  That
is a problem with the system library, not with MySQL.  Internally,
MySQL does not have any limit for the length of the password. To work
around the problem, change your MySQL password to a value that is eight
or fewer characters long, or put your password in an option file.

On Unix, MySQL programs treat the host name `localhost' specially, in a
way that is likely different from what you expect compared to other
network-based programs. For connections to `localhost', MySQL programs
attempt to connect to the local server by using a Unix socket file.
This occurs even if a `--port' or `-P' option is given to specify a
port number. To ensure that the client makes a TCP/IP connection to the
local server, use `--host' or `-h' to specify a host name value of
`127.0.0.1', or the IP address or name of the local server. You can
also specify the connection protocol explicitly, even for `localhost',
by using the `--protocol=TCP' option. For example:

     shell> mysql --host=127.0.0.1
     shell> mysql --protocol=TCP

The `--protocol' option enables you to establish a particular type of
connection even when the other options would normally default to some
other protocol.

On Windows, you can force a MySQL client to use a named-pipe connection
by specifying the `--pipe' or `--protocol=PIPE' option, or by
specifying `.' (period) as the host name. If named-pipe connections are
not enabled, an error occurs. Use the `--socket' option to specify the
name of the pipe if you do not want to use the default pipe name.

Connections to remote servers always use TCP/IP. This command connects
to the server running on `remote.example.com' using the default port
number (3306):

     shell> mysql --host=remote.example.com

To specify a port number explicitly, use the `--port' or `-P' option:

     shell> mysql --host=remote.example.com --port=13306

You can specify a port number for connections to a local server, too.
However, as indicated previously, connections to `localhost' on Unix
will use a socket file by default. You will need to force a TCP/IP
connection as already described or any option that specifies a port
number will be ignored.

For this command, the program uses a socket file on Unix and the
`--port' option is ignored:

     shell> mysql --port=13306 --host=localhost

To cause the port number to be used, invoke the program in either of
these ways:

     shell> mysql --port=13306 --host=127.0.0.1
     shell> mysql --port=13306 --protocol=TCP

The following list summarizes the options that can be used to control
how client programs connect to the server:

   *  `--host=HOST_NAME', `-h HOST_NAME'

     The host where the server is running. The default value is
     `localhost'.

   *  `--password[=PASS_VAL]', `-p[PASS_VAL]'

     The password of the MySQL account. As described earlier, the
     password value is optional, but if given, there must be _no space_
     between `-p' or `--password=' and the password following it. The
     default is to send no password.

   *  `--pipe', `-W'

     On Windows, connect to the server using a named pipe. The server
     must be started with the `--enable-named-pipe' option to enable
     named-pipe connections.

   *  `--port=PORT_NUM', `-P PORT_NUM'

     The port number to use for the connection, for connections made
     using TCP/IP. The default port number is 3306.

   *  `--protocol={TCP|SOCKET|PIPE|MEMORY}'

     This option explicitly specifies a protocol to use for connecting
     to the server. It is useful when the other connection parameters
     normally would cause a protocol to be used other than the one you
     want. For example, connections on Unix to `localhost' are made
     using a Unix socket file by default:

          shell> mysql --host=localhost

     To force a TCP/IP connection to be used instead, specify a
     `--protocol' option:

          shell> mysql --host=localhost --protocol=TCP

     The following table shows the permissible `--protocol' option
     values and indicates the platforms on which each value may be
     used. The values are not case sensitive.

     `--protocol'  Connection Protocol                Permissible
     Value                                            Operating Systems
     `TCP'         TCP/IP connection to local or      All
                   remote server                      
     `SOCKET'      Unix socket file connection to     Unix only
                   local server                       
     `PIPE'        Named-pipe connection to local or  Windows only
                   remote server                      
     `MEMORY'      Shared-memory connection to local  Windows only
                   server                             

   *  `--shared-memory-base-name=NAME'

     On Windows, the shared-memory name to use, for connections made
     using shared memory to a local server. The default value is
     `MYSQL'. The shared-memory name is case sensitive.

     The server must be started with the `--shared-memory' option to
     enable shared-memory connections.

   *  `--socket=FILE_NAME', `-S FILE_NAME'

     On Unix, the name of the Unix socket file to use, for connections
     made using a named pipe to a local server. The default Unix socket
     file name is `/tmp/mysql.sock'.

     On Windows, the name of the named pipe to use, for connections to
     a local server. The default Windows pipe name is `MySQL'. The pipe
     name is not case sensitive.

     The server must be started with the `--enable-named-pipe' option to
     enable named-pipe connections.

   * `--ssl*'

     Options that begin with `--ssl' are used for establishing a secure
     connection to the server using SSL, if the server is configured
     with SSL support. For details, see *Note ssl-options::.

   *  `--user=USER_NAME', `-u USER_NAME'

     The user name of the MySQL account you want to use. The default
     user name is `ODBC' on Windows or your Unix login name on Unix.

It is possible to specify different default values to be used when you
make a connection so that you need not enter them on the command line
each time you invoke a client program. This can be done in a couple of
ways:

   * You can specify connection parameters in the `[client]' section of
     an option file. The relevant section of the file might look like
     this:

          [client]
          host=HOST_NAME
          user=USER_NAME
          password=YOUR_PASS

     *Note option-files::, discusses option files further.

   * You can specify some connection parameters using environment
     variables. The host can be specified for *Note `mysql': mysql.
     using `MYSQL_HOST'.  The MySQL user name can be specified using
     `USER' (this is for Windows and NetWare only). The password can be
     specified using `MYSQL_PWD', although this is insecure; see *Note
     password-security-user::. For a list of variables, see *Note
     environment-variables::.


File: manual.info,  Node: program-options,  Next: setting-environment-variables,  Prev: connecting,  Up: programs-using

5.2.3 Specifying Program Options
--------------------------------

* Menu:

* command-line-options::         Using Options on the Command Line
* option-modifiers::             Program Option Modifiers
* option-files::                 Using Option Files
* program-variables::            Using Options to Set Program Variables
* option-defaults-equals::       Option Defaults, Options Expecting Values, and the `=' Sign

There are several ways to specify options for MySQL programs:

   * List the options on the command line following the program name.
     This is common for options that apply to a specific invocation of
     the program.

   * List the options in an option file that the program reads when it
     starts. This is common for options that you want the program to
     use each time it runs.

   * List the options in environment variables (see *Note
     setting-environment-variables::). This method is useful for
     options that you want to apply each time the program runs. In
     practice, option files are used more commonly for this purpose,
     but *Note multiple-unix-servers::, discusses one situation in
     which environment variables can be very helpful. It describes a
     handy technique that uses such variables to specify the TCP/IP
     port number and Unix socket file for the server and for client
     programs.

Options are processed in order, so if an option is specified multiple
times, the last occurrence takes precedence. The following command
causes *Note `mysql': mysql. to connect to the server running on
`localhost':

     shell> mysql -h example.com -h localhost

If conflicting or related options are given, later options take
precedence over earlier options. The following command runs *Note
`mysql': mysql. in `no column names' mode:

     shell> mysql --column-names --skip-column-names

MySQL programs determine which options are given first by examining
environment variables, then by reading option files, and then by
checking the command line. This means that environment variables have
the lowest precedence and command-line options the highest.

You can take advantage of the way that MySQL programs process options
by specifying default option values for a program in an option file.
That enables you to avoid typing them each time you run the program
while enabling you to override the defaults if necessary by using
command-line options.

An option can be specified by writing it in full or as any unambiguous
prefix. For example, the `--compress' option can be given to *Note
`mysqldump': mysqldump. as `--compr', but not as `--comp' because the
latter is ambiguous:

     shell> mysqldump --comp
     mysqldump: ambiguous option '--comp' (compatible, compress)

Be aware that the use of option prefixes can cause problems in the
event that new options are implemented for a program. A prefix that is
unambiguous now might become ambiguous in the future.


File: manual.info,  Node: command-line-options,  Next: option-modifiers,  Prev: program-options,  Up: program-options

5.2.3.1 Using Options on the Command Line
.........................................

Program options specified on the command line follow these rules:

   * Options are given after the command name.

   * An option argument begins with one dash or two dashes, depending
     on whether it is a short form or long form of the option name.
     Many options have both short and long forms.  For example, `-?'
     and `--help' are the short and long forms of the option that
     instructs a MySQL program to display its help message.

   * Option names are case sensitive. `-v' and `-V' are both legal and
     have different meanings. (They are the corresponding short forms
     of the `--verbose' and `--version' options.)

   * Some options take a value following the option name. For example,
     `-h localhost' or `--host=localhost' indicate the MySQL server
     host to a client program. The option value tells the program the
     name of the host where the MySQL server is running.

   * For a long option that takes a value, separate the option name and
     the value by an ``='' sign. For a short option that takes a value,
     the option value can immediately follow the option letter, or
     there can be a space between: `-hlocalhost' and `-h localhost' are
     equivalent. An exception to this rule is the option for specifying
     your MySQL password. This option can be given in long form as
     `--password=PASS_VAL' or as `--password'. In the latter case (with
     no password value given), the program prompts you for the
     password. The password option also may be given in short form as
     `-pPASS_VAL' or as `-p'. However, for the short form, if the
     password value is given, it must follow the option letter with _no
     intervening space_. The reason for this is that if a space follows
     the option letter, the program has no way to tell whether a
     following argument is supposed to be the password value or some
     other kind of argument. Consequently, the following two commands
     have two completely different meanings:

          shell> mysql -ptest
          shell> mysql -p test

     The first command instructs *Note `mysql': mysql. to use a
     password value of `test', but specifies no default database. The
     second instructs *Note `mysql': mysql. to prompt for the password
     value and to use `test' as the default database.

   * Within option names, dash (``-'') and underscore (``_'') may be
     used interchangeably. For example, `--skip-grant-tables' and
     `--skip_grant_tables' are equivalent. (However, the leading dashes
     cannot be given as underscores.)

   * For options that take a numeric value, the value can be given with
     a suffix of `K', `M', or `G' (either uppercase or lowercase) to
     indicate a multiplier of 1024, 1024^2 or 1024^3. For example, the
     following command tells *Note `mysqladmin': mysqladmin. to ping the
     server 1024 times, sleeping 10 seconds between each ping:

          mysql> mysqladmin --count=1K --sleep=10 ping

Option values that contain spaces must be quoted when given on the
command line. For example, the `--execute' (or `-e') option can be used
with *Note `mysql': mysql. to pass SQL statements to the server. When
this option is used, *Note `mysql': mysql. executes the statements in
the option value and exits. The statements must be enclosed by quotation
marks. For example, you can use the following command to obtain a list
of user accounts:

     mysql> mysql -u root -p --execute="SELECT User, Host FROM mysql.user"
     Enter password: ******
     +------+-----------+
     | User | Host      |
     +------+-----------+
     |      | gigan     |
     | root | gigan     |
     |      | localhost |
     | jon  | localhost |
     | root | localhost |
     +------+-----------+
     shell>

Note that the long form (`--execute') is followed by an equal sign
(`=').

If you wish to use quoted values within a statement, you will either
need to escape the inner quotation marks, or use a different type of
quotation marks within the statement from those used to quote the
statement itself. The capabilities of your command processor dictate
your choices for whether you can use single or double quotation marks
and the syntax for escaping quote characters. For example, if your
command processor supports quoting with single or double quotation
marks, you can use double quotation marks around the statement, and
single quotation marks for any quoted values within the statement.

Multiple SQL statements may be passed in the option value on the
command line, separated by semicolons:

     shell> mysql -u root -p -e "SELECT VERSION();SELECT NOW()"
     Enter password: ******
     +------------+
     | VERSION()  |
     +------------+
     | 5.0.19-log |
     +------------+
     +---------------------+
     | NOW()               |
     +---------------------+
     | 2006-01-05 21:19:04 |
     +---------------------+

The `--execute' or `-e' option may also be used to pass commands in an
analogous fashion to the *Note `ndb_mgm':
mysql-cluster-programs-ndb-mgm. management client for MySQL Cluster.
See *Note mysql-cluster-install-shutdown-restart::, for an example.


File: manual.info,  Node: option-modifiers,  Next: option-files,  Prev: command-line-options,  Up: program-options

5.2.3.2 Program Option Modifiers
................................

Some options are `boolean' and control behavior that can be turned on
or off. For example, the *Note `mysql': mysql. client supports a
`--column-names' option that determines whether or not to display a row
of column names at the beginning of query results. By default, this
option is enabled. However, you may want to disable it in some
instances, such as when sending the output of *Note `mysql': mysql. into
another program that expects to see only data and not an initial header
line.

To disable column names, you can specify the option using any of these
forms:

     --disable-column-names
     --skip-column-names
     --column-names=0

The `--disable' and `--skip' prefixes and the `=0' suffix all have the
same effect: They turn the option off.

The `enabled' form of the option may be specified in any of these ways:

     --column-names
     --enable-column-names
     --column-names=1

If an option is prefixed by `--loose', a program does not exit with an
error if it does not recognize the option, but instead issues only a
warning:

     shell> mysql --loose-no-such-option
     mysql: WARNING: unknown option '--no-such-option'

The `--loose' prefix can be useful when you run programs from multiple
installations of MySQL on the same machine and list options in an
option file, An option that may not be recognized by all versions of a
program can be given using the `--loose' prefix (or `loose' in an
option file). Versions of the program that recognize the option process
it normally, and versions that do not recognize it issue a warning and
ignore it.

*Note `mysqld': mysqld. enables a limit to be placed on how large
client programs can set dynamic system variables. To do this, use a
`--maximum' prefix with the variable name. For example,
`--maximum-query_cache_size=4M' prevents any client from making the
query cache size larger than 4MB.


File: manual.info,  Node: option-files,  Next: program-variables,  Prev: option-modifiers,  Up: program-options

5.2.3.3 Using Option Files
..........................

* Menu:

* option-file-options::          Command-Line Options that Affect Option-File Handling
* option-files-preconfigured::   Preconfigured Option Files

Most MySQL programs can read startup options from option files (also
sometimes called configuration files). Option files provide a
convenient way to specify commonly used options so that they need not
be entered on the command line each time you run a program. For the
MySQL server, MySQL provides a number of *Note preconfigured option
files: option-files-preconfigured.

To determine whether a program reads option files, invoke it with the
`--help' option. (For *Note `mysqld': mysqld, use `--verbose' and
`--help'.) If the program reads option files, the help message
indicates which files it looks for and which option groups it
recognizes.

*Note*:

Option files used with MySQL Cluster programs are covered in *Note
mysql-cluster-configuration::.

On Windows, MySQL programs read startup options from the following
files, in the specified order (top items are used first).

File Name              Purpose
`WINDIR\my.ini',       Global options
`WINDIR\my.cnf'        
`C:\my.ini',           Global options
`C:\my.cnf'            
`INSTALLDIR\my.ini',   Global options
`INSTALLDIR\my.cnf'    
`defaults-extra-file'  The file specified with
                       `--defaults-extra-file=PATH', if any

WINDIR represents the location of your Windows directory. This is
commonly `C:\WINDOWS'. You can determine its exact location from the
value of the `WINDIR' environment variable using the following command:

     C:\> echo %WINDIR%

INSTALLDIR represents the MySQL installation directory. This is
typically `C:\PROGRAMDIR\MySQL\MySQL 5.0 Server' where PROGRAMDIR
represents the programs directory (usually `Program Files' on
English-language versions of Windows), when MySQL 5.0 has been
installed using the installation and configuration wizards. See *Note
mysql-config-wizard-starting::.

On Unix, Linux and Mac OS X, MySQL programs read startup options from
the following files, in the specified order (top items are used first).

File Name              Purpose
`/etc/my.cnf'          Global options
`SYSCONFDIR/my.cnf'    Global options
`$MYSQL_HOME/my.cnf'   Server-specific options
`defaults-extra-file'  The file specified with
                       `--defaults-extra-file=PATH', if any
`~/.my.cnf'            User-specific options

`~' represents the current user's home directory (the value of `$HOME').

SYSCONFDIR represents the directory specified with the `--sysconfdir'
option to `configure' when MySQL was built. By default, this is the
`etc' directory located under the compiled-in installation directory.
This location is used as of MySQL 5.0.21. (From 5.0.21 to 5.0.53, it
was read last, after `~/.my.cnf'.)

`MYSQL_HOME' is an environment variable containing the path to the
directory in which the server-specific `my.cnf' file resides. (This was
DATADIR prior to MySQL version 5.0.3.)

If `MYSQL_HOME' is not set and you start the server using the *Note
`mysqld_safe': mysqld-safe. program, *Note `mysqld_safe': mysqld-safe.
attempts to set `MYSQL_HOME' as follows:

   * Let BASEDIR and DATADIR represent the path names of the MySQL base
     directory and data directory, respectively.

   * If there is a `my.cnf' file in DATADIR but not in BASEDIR, *Note
     `mysqld_safe': mysqld-safe. sets `MYSQL_HOME' to DATADIR.

   * Otherwise, if `MYSQL_HOME' is not set and there is no `my.cnf'
     file in DATADIR, *Note `mysqld_safe': mysqld-safe. sets
     `MYSQL_HOME' to BASEDIR.

In MySQL 5.0, use of DATADIR as the location for `my.cnf' is deprecated.

Typically, DATADIR is `/usr/local/mysql/data' for a binary installation
or `/usr/local/var' for a source installation. Note that this is the
data directory location that was specified at configuration time, not
the one specified with the `--datadir' option when *Note `mysqld':
mysqld. starts. Use of `--datadir' at runtime has no effect on where
the server looks for option files, because it looks for them before
processing any options.

MySQL looks for option files in the order just described and reads any
that exist. If an option file that you want to use does not exist,
create it with a plain text editor.

If multiple instances of a given option are found, the last instance
takes precedence. There is one exception: For *Note `mysqld': mysqld,
the _first_ instance of the `--user' option is used as a security
precaution, to prevent a user specified in an option file from being
overridden on the command line.

*Note*:

On Unix platforms, MySQL ignores configuration files that are
world-writable. This is intentional as a security measure.

Any long option that may be given on the command line when running a
MySQL program can be given in an option file as well.  To get the list
of available options for a program, run it with the `--help' option.

The syntax for specifying options in an option file is similar to
command-line syntax (see *Note command-line-options::). However, in an
option file, you omit the leading two dashes from the option name and
you specify only one option per line. For example, `--quick' and
`--host=localhost' on the command line should be specified as `quick'
and `host=localhost' on separate lines in an option file. To specify an
option of the form `--loose-OPT_NAME' in an option file, write it as
`loose-OPT_NAME'.

Empty lines in option files are ignored. Nonempty lines can take any of
the following forms:

   * `#COMMENT', `;COMMENT'

     Comment lines start with ``#'' or ``;''. A ``#'' comment can start
     in the middle of a line as well.

   * `[GROUP]'

     GROUP is the name of the program or group for which you want to
     set options. After a group line, any option-setting lines apply to
     the named group until the end of the option file or another group
     line is given.

   * `OPT_NAME'

     This is equivalent to `--OPT_NAME' on the command line.

   * `OPT_NAME=VALUE'

     This is equivalent to `--OPT_NAME=VALUE' on the command line. In
     an option file, you can have spaces around the ``='' character,
     something that is not true on the command line. You can optionally
     enclose the value within single quotation marks or double
     quotation marks, which is useful if the value contains a ``#''
     comment character.

Leading and trailing spaces are automatically deleted from option names
and values.

You can use the escape sequences ``\b'', ``\t'', ``\n'', ``\r'',
``\\'', and ``\s'' in option values to represent the backspace, tab,
newline, carriage return, backslash, and space characters. The escaping
rules in option files are:

   * If a backslash is followed by a valid escape sequence character,
     the sequence is converted to the character represented by the
     sequence. For example, ``\s'' is converted to a space.

   * If a backslash is not followed by a valid escape sequence
     character, it remains unchanged. For example, ``\S'' is retained
     as is.

The preceding rules mean that a literal backslash can be given as
``\\'', or as ``\'' if it is not followed by a valid escape sequence
character.

The rules for escape sequences in option files differ slightly from the
rules for escape sequences in string literals in SQL statements. In the
latter context, if `X' is not a value escape sequence character, ``\X''
becomes `X' rather than ``\X''.  See *Note string-literals::.

The escaping rules for option file values are especially pertinent for
Windows path names, which use ``\'' as a path name separator. A
separator in a Windows path name must be written as ``\\'' if it is
followed by an escape sequence character. It can be written as ``\\'' or
``\'' if it is not. Alternatively, ``/'' may be used in Windows path
names and will be treated as ``\''. Suppose that you want to specify a
base directory of `C:\Program Files\MySQL\MySQL Server 5.0' in an
option file. This can be done several ways. Some examples:

     basedir="C:\Program Files\MySQL\MySQL Server 5.0"
     basedir="C:\\Program Files\\MySQL\\MySQL Server 5.0"
     basedir="C:/Program Files/MySQL/MySQL Server 5.0"
     basedir=C:\\Program\sFiles\\MySQL\\MySQL\sServer\s5.0

If an option group name is the same as a program name, options in the
group apply specifically to that program. For example, the `[mysqld]'
and `[mysql]' groups apply to the *Note `mysqld': mysqld. server and the
*Note `mysql': mysql. client program, respectively.

The `[client]' option group is read by all client programs (but _not_ by
*Note `mysqld': mysqld.). This enables you to specify options that
apply to all clients. For example, `[client]' is the perfect group to
use to specify the password that you use to connect to the server. (But
make sure that the option file is readable and writable only by
yourself, so that other people cannot find out your password.)  Be sure
not to put an option in the `[client]' group unless it is recognized by
_all_ client programs that you use. Programs that do not understand the
option quit after displaying an error message if you try to run them.

Here is a typical global option file:

     [client]
     port=3306
     socket=/tmp/mysql.sock

     [mysqld]
     port=3306
     socket=/tmp/mysql.sock
     key_buffer_size=16M
     max_allowed_packet=8M

     [mysqldump]
     quick

The preceding option file uses `VAR_NAME=VALUE' syntax for the lines
that set the `key_buffer_size' and `max_allowed_packet' variables.

Here is a typical user option file:

     [client]
     # The following password will be sent to all standard MySQL clients
     password="my_password"

     [mysql]
     no-auto-rehash
     connect_timeout=2

     [mysqlhotcopy]
     interactive-timeout

If you want to create option groups that should be read by *Note
`mysqld': mysqld. servers from a specific MySQL release series only,
you can do this by using groups with names of `[mysqld-4.1]',
`[mysqld-5.0]', and so forth. The following group indicates that the
`--new' option should be used only by MySQL servers with 5.0.x version
numbers:

     [mysqld-5.0]
     new

Beginning with MySQL 5.0.4, it is possible to use `!include' directives
in option files to include other option files and `!includedir' to
search specific directories for option files. For example, to include
the `/home/mydir/myopt.cnf' file, use the following directive:

     !include /home/mydir/myopt.cnf

To search the `/home/mydir' directory and read option files found
there, use this directive:

     !includedir /home/mydir

There is no guarantee about the order in which the option files in the
directory will be read.

*Note*:

Currently, any files to be found and included using the `!includedir'
directive on Unix operating systems _must_ have file names ending in
`.cnf'. On Windows, this directive checks for files with the `.ini' or
`.cnf' extension.

Write the contents of an included option file like any other option
file. That is, it should contain groups of options, each preceded by a
`[GROUP]' line that indicates the program to which the options apply.

While an included file is being processed, only those options in groups
that the current program is looking for are used. Other groups are
ignored. Suppose that a `my.cnf' file contains this line:

     !include /home/mydir/myopt.cnf

And suppose that `/home/mydir/myopt.cnf' looks like this:

     [mysqladmin]
     force

     [mysqld]
     key_buffer_size=16M

If `my.cnf' is processed by *Note `mysqld': mysqld, only the `[mysqld]'
group in `/home/mydir/myopt.cnf' is used. If the file is processed by
*Note `mysqladmin': mysqladmin, only the `[mysqladmin]' group is used.
If the file is processed by any other program, no options in
`/home/mydir/myopt.cnf' are used.

The `!includedir' directive is processed similarly except that all
option files in the named directory are read.


File: manual.info,  Node: option-file-options,  Next: option-files-preconfigured,  Prev: option-files,  Up: option-files

5.2.3.4 Command-Line Options that Affect Option-File Handling
.............................................................

Most MySQL programs that support option files handle the following
options. They affect option-file handling, so they must be given on the
command line and not in an option file.  To work properly, each of
these options must immediately follow the command name, with these
exceptions:

   * `--print-defaults' may be used immediately after `--defaults-file'
     or `--defaults-extra-file'.

   * On Windows, if the `--defaults-file' and `--install' options are
     given, `--install' option must be first. See *Note
     windows-start-service::.

When specifying file names, you should avoid the use of the ``~'' shell
metacharacter because it might not be interpreted as you expect.

   *  `--defaults-extra-file=FILE_NAME'

     Read this option file after the global option file but (on Unix)
     before the user option file. As of MySQL 5.0.6, if the file does
     not exist or is otherwise inaccessible, the program exits with an
     error.  FILE_NAME is the full path name to the file.

   *  `--defaults-file=FILE_NAME'

     Use only the given option file. If the file does not exist or is
     otherwise inaccessible, the program exits with an error. FILE_NAME
     is the full path name to the file.

   *  `--defaults-group-suffix=STR'

     If this option is given, the program reads not only its usual
     option groups, but also groups with the usual names and a suffix
     of STR. For example, the *Note `mysql': mysql. client normally
     reads the `[client]' and `[mysql]' groups. If the
     `--defaults-group-suffix=_other' option is given, *Note `mysql':
     mysql. also reads the `[client_other]' and `[mysql_other]' groups.
     This option was added in MySQL 5.0.10.

   *  `--no-defaults'

     Do not read any option files. If a program does not start because
     it is reading unknown options from an option file, `--no-defaults'
     can be used to prevent the program from reading them.

   *  `--print-defaults'

     Print the program name and all options that it gets from option
     files.


File: manual.info,  Node: option-files-preconfigured,  Prev: option-file-options,  Up: option-files

5.2.3.5 Preconfigured Option Files
..................................

MySQL provides a number of preconfigured option files that can be used
as a basis for tuning the MySQL server. Look for files such as
`my-small.cnf', `my-medium.cnf', `my-large.cnf', and `my-huge.cnf',
which are sample option files for small, medium, large, and very large
systems. On Windows, the extension is `.ini' rather than `.cnf'.

*Note*:

On Windows, the `.ini' or `.cnf' option file extension might not be
displayed.

For a binary distribution, look for the files in or under your
installation directory. If you have a source distribution, look in the
`support-files' directory. You can rename a copy of a sample file and
place it in the appropriate location for use as a base configuration
file.  Regarding names and appropriate location, see the general
information provided in *Note option-files::.


File: manual.info,  Node: program-variables,  Next: option-defaults-equals,  Prev: option-files,  Up: program-options

5.2.3.6 Using Options to Set Program Variables
..............................................

Many MySQL programs have internal variables that can be set at runtime
using the *Note `SET': set-option.  statement. See *Note set-option::,
and *Note using-system-variables::.

Most of these program variables also can be set at server startup by
using the same syntax that applies to specifying program options. For
example, *Note `mysql': mysql. has a `max_allowed_packet' variable that
controls the maximum size of its communication buffer. To set the
`max_allowed_packet' variable for *Note `mysql': mysql. to a value of
16MB, use either of the following commands:

     shell> mysql --max_allowed_packet=16777216
     shell> mysql --max_allowed_packet=16M

The first command specifies the value in bytes. The second specifies
the value in megabytes. For variables that take a numeric value, the
value can be given with a suffix of `K', `M', or `G' (either uppercase
or lowercase) to indicate a multiplier of 1024, 1024^2 or 1024^3. (For
example, when used to set `max_allowed_packet', the suffixes indicate
units of kilobytes, megabytes, or gigabytes.)

In an option file, variable settings are given without the leading
dashes:

     [mysql]
     max_allowed_packet=16777216

Or:

     [mysql]
     max_allowed_packet=16M

If you like, underscores in a variable name can be specified as dashes.
The following option groups are equivalent. Both set the size of the
server's key buffer to 512MB:

     [mysqld]
     key_buffer_size=512M

     [mysqld]
     key-buffer-size=512M

A variable can be specified by writing it in full or as any unambiguous
prefix. For example, the `max_allowed_packet' variable can be set for
*Note `mysql': mysql. as `--max_a', but not as `--max' because the
latter is ambiguous:

     shell> mysql --max=1000000
     mysql: ambiguous option '--max=1000000' (max_allowed_packet, max_join_size)

Be aware that the use of variable prefixes can cause problems in the
event that new variables are implemented for a program. A prefix that
is unambiguous now might become ambiguous in the future.

Suffixes for specifying a value multiplier can be used when setting a
variable at server startup, but not to set the value with *Note `SET':
set-option.  at runtime. On the other hand, with *Note `SET':
set-option. you can assign a variable's value using an expression,
which is not true when you set a variable at server startup. For
example, the first of the following lines is legal at server startup,
but the second is not:

     shell> mysql --max_allowed_packet=16M
     shell> mysql --max_allowed_packet=16*1024*1024

Conversely, the second of the following lines is legal at runtime, but
the first is not:

     mysql> SET GLOBAL max_allowed_packet=16M;
     mysql> SET GLOBAL max_allowed_packet=16*1024*1024;

*Note*:

Before MySQL 4.0.2, the only syntax for setting program variables was
`--set-variable=OPTION=VALUE' (or `set-variable=OPTION=VALUE' in option
files). Underscores cannot be given as dashes, and the variable name
must be specified in full. This syntax still is recognized, but is now
deprecated and is removed in MySQL 5.5.


File: manual.info,  Node: option-defaults-equals,  Prev: program-variables,  Up: program-options

5.2.3.7 Option Defaults, Options Expecting Values, and the `=' Sign
...................................................................

By convention, long forms of options that assign a value are written
with an equals (`=') sign, like this:

     shell> mysql --host=tonfisk --user=jon

For options that require a value (that is, not having a default value),
the equal sign is not required, and so the following is also valid:

     shell> mysql --host tonfisk --user jon

In both cases, the *Note `mysql': mysql. client attempts to connect to
a MySQL server running on the host named `tonfisk' using an account
with the user name `jon'.

Due to this behavior, problems can occasionally arise when no value is
provided for an option that expects one. Consider the following
example, where a user connects to a MySQL server running on host
`tonfisk' as user `jon':

     shell> mysql --host 85.224.35.45 --user jon
     Welcome to the MySQL monitor.  Commands end with ; or \g.
     Your MySQL connection id is 3
     Server version: 5.0.95 Source distribution

     Type 'help;' or '\h' for help. Type '\c' to clear the buffer.

     mysql> SELECT CURRENT_USER();
     +----------------+
     | CURRENT_USER() |
     +----------------+
     | jon@%          |
     +----------------+
     1 row in set (0.00 sec)

Omitting the required value for one of these option yields an error,
such as the one shown here:

     shell> mysql --host 85.224.35.45 --user
     `mysql: option '--user' requires an argument'

In this case, *Note `mysql': mysql. was unable to find a value
following the `--user' option because nothing came after it on the
command line.  However, if you omit the value for an option that is
_not_ the last option to be used, you obtain a different error that you
may not be expecting:

     shell> mysql --host --user jon
     `ERROR 2005 (HY000): Unknown MySQL server host '--user' (1)'

Because *Note `mysql': mysql. assumes that any string following
`--host' on the command line is a host name, `--host' `--user' is
interpreted as `--host=--user', and the client attempts to connect to a
MySQL server running on a host named `--user'.

Options having default values always require an equal sign when
assigning a value; failing to do so causes an error. For example, the
MySQL server `--log-error' option has the default value `HOST_NAME.err',
where HOST_NAME is the name of the host on which MySQL is running.
Assume that you are running MySQL on a computer whose host name is
`tonfisk', and consider the following invocation of *Note
`mysqld_safe': mysqld-safe.:

     shell> mysqld_safe &
     [1] 11699
     shell> 080112 12:53:40 mysqld_safe Logging to '/usr/local/mysql/var/tonfisk.err'.
     080112 12:53:40 mysqld_safe Starting mysqld daemon with databases from /usr/local/mysql/var
     shell>

After shutting down the server, restart it as follows:

     shell> mysqld_safe --log-error &
     [1] 11699
     shell> 080112 12:53:40 mysqld_safe Logging to '/usr/local/mysql/var/tonfisk.err'.
     080112 12:53:40 mysqld_safe Starting mysqld daemon with databases from /usr/local/mysql/var
     shell>

The result is the same, since `--log-error' is not followed by anything
else on the command line, and it supplies its own default value. (The
`&' character tells the operating system to run MySQL in the
background; it is ignored by MySQL itself.) Now suppose that you wish
to log errors to a file named `my-errors.err'. You might try starting
the server with `--log-error my-errors', but this does not have the
intended effect, as shown here:

     shell> mysqld_safe --log-error my-errors &
     [1] 31357
     shell> 080111 22:53:31 mysqld_safe Logging to '/usr/local/mysql/var/tonfisk.err'.
     080111 22:53:32 mysqld_safe Starting mysqld daemon with databases from /usr/local/mysql/var
     080111 22:53:34 mysqld_safe mysqld from pid file /usr/local/mysql/var/tonfisk.pid ended

     [1]+  Done                    ./mysqld_safe --log-error my-errors

The server attempted to start using `/usr/local/mysql/var/tonfisk.err'
as the error log, but then shut down. Examining the last few lines of
this file shows the reason:

     shell> tail /usr/local/mysql/var/tonfisk.err
     080111 22:53:32  InnoDB: Started; log sequence number 0 46409
     `/usr/local/mysql/libexec/mysqld: Too many arguments (first extra is 'my-errors').
     Use --verbose --help to get a list of available options'
     080111 22:53:32 `[ERROR] Aborting'

     080111 22:53:32  InnoDB: Starting shutdown...
     080111 22:53:34  InnoDB: Shutdown completed; log sequence number 0 46409
     080111 22:53:34 [Note] /usr/local/mysql/libexec/mysqld: Shutdown complete

     080111 22:53:34 mysqld_safe mysqld from pid file /usr/local/mysql/var/tonfisk.pid ended

Because the `--log-error' option supplies a default value, you must use
an equal sign to assign a different value to it, as shown here:

     shell> mysqld_safe --log-error=my-errors &
     [1] 31437
     shell> 080111 22:54:15 mysqld_safe Logging to '/usr/local/mysql/var/my-errors.err'.
     080111 22:54:15 mysqld_safe Starting mysqld daemon with databases from /usr/local/mysql/var

     shell>

Now the server has been started successfully, and is logging errors to
the file `/usr/local/mysql/var/my-errors.err'.

Similar issues can arise when specifying option values in option files.
For example, consider a `my.cnf' file that contains the following:

     [mysql]

     host
     user

When the *Note `mysql': mysql. client reads this file, these entries
are parsed as `--host' `--user' or `--host=--user', with the result
shown here:

     shell> mysql
     `ERROR 2005 (HY000): Unknown MySQL server host '--user' (1)'

However, in option files, an equal sign is not assumed. Suppose the
`my.cnf' file is as shown here:

     [mysql]

     user jon

Trying to start *Note `mysql': mysql. in this case causes a different
error:

     shell> mysql
     `mysql: unknown option '--user jon''

A similar error would occur if you were to write `host tonfisk' in the
option file rather than `host=tonfisk'. Instead, you must use the
equals sign:

     [mysql]

     user=jon

Now the login attempt succeeds:

     shell> mysql
     Welcome to the MySQL monitor.  Commands end with ; or \g.
     Your MySQL connection id is 5
     Server version: 5.0.95 Source distribution

     Type 'help;' or '\h' for help. Type '\c' to clear the buffer.

     mysql> SELECT USER();
     +---------------+
     | USER()        |
     +---------------+
     | jon@localhost |
     +---------------+
     1 row in set (0.00 sec)

This is not the same behavior as with the command line, where the
equals sign is not required:

     shell> mysql --user jon --host tonfisk
     Welcome to the MySQL monitor.  Commands end with ; or \g.
     Your MySQL connection id is 6
     Server version: 5.0.95 Source distribution

     Type 'help;' or '\h' for help. Type '\c' to clear the buffer.

     mysql> SELECT USER();
     +---------------+
     | USER()        |
     +---------------+
     | jon@tonfisk   |
     +---------------+
     1 row in set (0.00 sec)


File: manual.info,  Node: setting-environment-variables,  Prev: program-options,  Up: programs-using

5.2.4 Setting Environment Variables
-----------------------------------

Environment variables can be set at the command prompt to affect the
current invocation of your command processor, or set permanently to
affect future invocations. To set a variable permanently, you can set
it in a startup file or by using the interface provided by your system
for this purpose. Consult the documentation for your command
interpreter for specific details.  *Note environment-variables::, lists
all environment variables that affect MySQL program operation.

To specify a value for an environment variable, use the syntax
appropriate for your command processor. For example, on Windows or
NetWare, you can set the `USER' variable to specify your MySQL account
name. To do so, use this syntax:

     SET USER=YOUR_NAME

The syntax on Unix depends on your shell. Suppose that you want to
specify the TCP/IP port number using the `MYSQL_TCP_PORT' variable.
Typical syntax (such as for `sh', `bash', `zsh', and so on) is as
follows:

     MYSQL_TCP_PORT=3306
     export MYSQL_TCP_PORT

The first command sets the variable, and the `export' command exports
the variable to the shell environment so that its value becomes
accessible to MySQL and other processes.

For `csh' and `tcsh', use `setenv' to make the shell variable available
to the environment:

     setenv MYSQL_TCP_PORT 3306

The commands to set environment variables can be executed at your
command prompt to take effect immediately, but the settings persist
only until you log out. To have the settings take effect each time you
log in, use the interface provided by your system or place the
appropriate command or commands in a startup file that your command
interpreter reads each time it starts.

On Windows, you can set environment variables using the System Control
Panel (under Advanced).

On Unix, typical shell startup files are `.bashrc' or `.bash_profile'
for `bash', or `.tcshrc' for `tcsh'.

Suppose that your MySQL programs are installed in
`/usr/local/mysql/bin' and that you want to make it easy to invoke
these programs. To do this, set the value of the `PATH' environment
variable to include that directory. For example, if your shell is
`bash', add the following line to your `.bashrc' file:

     PATH=${PATH}:/usr/local/mysql/bin

`bash' uses different startup files for login and nonlogin shells, so
you might want to add the setting to `.bashrc' for login shells and to
`.bash_profile' for nonlogin shells to make sure that `PATH' is set
regardless.

If your shell is `tcsh', add the following line to your `.tcshrc' file:

     setenv PATH ${PATH}:/usr/local/mysql/bin

If the appropriate startup file does not exist in your home directory,
create it with a text editor.

After modifying your `PATH' setting, open a new console window on
Windows or log in again on Unix so that the setting goes into effect.


File: manual.info,  Node: programs-server,  Next: programs-installation,  Prev: programs-using,  Up: programs

5.3 MySQL Server and Server-Startup Programs
============================================

* Menu:

* mysqld::                       `mysqld' --- The MySQL Server
* mysqld-safe::                  `mysqld_safe' --- MySQL Server Startup Script
* mysql-server::                 `mysql.server' --- MySQL Server Startup Script
* mysqld-multi::                 `mysqld_multi' --- Manage Multiple MySQL Servers

This section describes *Note `mysqld': mysqld, the MySQL server, and
several programs that are used to start the server.


File: manual.info,  Node: mysqld,  Next: mysqld-safe,  Prev: programs-server,  Up: programs-server

5.3.1 `mysqld' -- The MySQL Server
----------------------------------

*Note `mysqld': mysqld, also known as MySQL Server, is the main program
that does most of the work in a MySQL installation.  MySQL Server
manages access to the MySQL data directory that contains databases and
tables. The data directory is also the default location for other
information such as log files and status files.

When MySQL server starts, it listens for network connections from
client programs and manages access to databases on behalf of those
clients.

The *Note `mysqld': mysqld. program has many options that can be
specified at startup. For a complete list of options, run this command:

     shell> mysqld --verbose --help

MySQL Server also has a set of system variables that affect its
operation as it runs. System variables can be set at server startup,
and many of them can be changed at runtime to effect dynamic server
reconfiguration. MySQL Server also has a set of status variables that
provide information about its operation.  You can monitor these status
variables to access runtime performance characteristics.

For a full description of MySQL Server command options, system
variables, and status variables, see *Note mysqld-server::. For
information about installing MySQL and setting up the initial
configuration, see *Note installing::.


File: manual.info,  Node: mysqld-safe,  Next: mysql-server,  Prev: mysqld,  Up: programs-server

5.3.2 `mysqld_safe' -- MySQL Server Startup Script
--------------------------------------------------

*Note `mysqld_safe': mysqld-safe. is the recommended way to start a
*Note `mysqld': mysqld. server on Unix and NetWare.  *Note
`mysqld_safe': mysqld-safe. adds some safety features such as
restarting the server when an error occurs and logging runtime
information to an error log file. NetWare-specific behaviors are listed
later in this section.

*Note*:

To preserve backward compatibility with older versions of MySQL, MySQL
binary distributions still include `safe_mysqld' as a symbolic link to
*Note `mysqld_safe': mysqld-safe. However, you should not rely on this
because it is removed as of MySQL 5.1.

By default, *Note `mysqld_safe': mysqld-safe. before MySQL 5.0.27 tries
to start an executable named `mysqld-max' if it exists, and *Note
`mysqld': mysqld. otherwise. Be aware of the implications of this
behavior:

   * On Linux, the `MySQL-Max' RPM relies on this *Note `mysqld_safe':
     mysqld-safe. behavior. The RPM installs an executable named
     `mysqld-max', which causes *Note `mysqld_safe': mysqld-safe. to
     automatically use that executable rather than *Note `mysqld':
     mysqld.  from that point on.

   * If you install a MySQL-Max distribution that includes a server
     named `mysqld-max', and then upgrade later to a non-Max version of
     MySQL, *Note `mysqld_safe': mysqld-safe. will still attempt to run
     the old `mysqld-max' server. If you perform such an upgrade, you
     should manually remove the old `mysqld-max' server to ensure that
     *Note `mysqld_safe': mysqld-safe. runs the new *Note `mysqld':
     mysqld. server.

To override the default behavior and specify explicitly the name of the
server you want to run, specify a `--mysqld' or `--mysqld-version'
option to *Note `mysqld_safe': mysqld-safe. You can also use `--ledir'
to indicate the directory where *Note `mysqld_safe': mysqld-safe.
should look for the server.

Many of the options to *Note `mysqld_safe': mysqld-safe. are the same
as the options to *Note `mysqld': mysqld. See *Note server-options::.

Options unknown to *Note `mysqld_safe': mysqld-safe. are passed to
*Note `mysqld': mysqld. if they are specified on the command line, but
ignored if they are specified in the `[mysqld_safe]' group of an option
file. See *Note option-files::.

*Note `mysqld_safe': mysqld-safe. reads all options from the
`[mysqld]', `[server]', and `[mysqld_safe]' sections in option files.
For example, if you specify a `[mysqld]' section like this, *Note
`mysqld_safe': mysqld-safe. will find and use the `--log-error' option:

     [mysqld]
     log-error=error.log

For backward compatibility, *Note `mysqld_safe': mysqld-safe. also
reads `[safe_mysqld]' sections, although you should rename such
sections to `[mysqld_safe]' in MySQL 5.0 installations.

*Note `mysqld_safe': mysqld-safe. supports the following options.  It
also reads option files and supports the options for processing them
described at *Note option-file-options::.

*`mysqld_safe' Options*

Format      Option File Description                   IntroductionDeprecatedRemoved
-autoclose  autoclose   On NetWare, mysqld_safe                       
                        provides a screen presence                    
-basedir=pathbasedir     The path to the MySQL                         
                        installation directory                        
-core-file-size=sizecore-file-sizeThe size of the core file                     
                        that mysqld should be able                    
                        to create                                     
-datadir=pathdatadir     The path to the data                          
                        directory                                     
-defaults-extra-file=pathdefaults-extra-fileThe name of an option file                    
                        to be read in addition to                     
                        the usual  option files                       
-defaults-file=file_namedefaults-fileThe name of an option file                    
                        to be read instead of the                     
                        usual option  files                           
-help                   Display a help message and    5.0.3           
                        exit                                          
-ledir=path ledir       Use this option to indicate                   
                        the path name to the                          
                        directory where  the server                   
                        is located                                    
-log-error=file_namelog-error   Write the error log to the                    
                        given file                                    
-mysqld=prog_namemysqld      The name of the server                        
                        program (in the ledir                         
                        directory) that you  want to                  
                        start                                         
-mysqld-version=suffixmysqld-versionThis option is similar to                     
                        the -mysqld option, but you                   
                        specify  only the suffix for                  
                        the server program name                       
-nice=prioritynice        Use the nice program to set                   
                        the server's scheduling                       
                        priority to  the given value                  
-no-defaultsno-defaults Do not read any option files                  
-open-files-limit=countopen-files-limitThe number of files that                      
                        mysqld should be able to open                 
-pid-file=file_namepid-file=file_nameThe path name of the process                  
                        ID file                                       
-port=numberport        The port number that the                      
                        server should use when                        
                        listening for  TCP/IP                         
                        connections                                   
-skip-kill-mysqldskip-kill-mysqldDo not try to kill stray                      
                        mysqld processes                              
-socket=pathsocket      The Unix socket file that                     
                        the server should use when                    
                        listening for  local                          
                        connections                                   
-timezone=timezonetimezone    Set the TZ time zone                          
                        environment variable to the                   
                        given option  value                           
-user={user_name|user_id}user        Run the mysqld server as the                  
                        user having the name                          
                        user_name or the  numeric                     
                        user ID user_id                               

   *  `--help'

     Display a help message and exit. (Added in MySQL 5.0.3)

   *  `--autoclose'

     (NetWare only) On NetWare, *Note `mysqld_safe': mysqld-safe.
     provides a screen presence. When you unload (shut down) the *Note
     `mysqld_safe': mysqld-safe. NLM, the screen does not by default go
     away. Instead, it prompts for user input:

          *<NLM has terminated; Press any key to close the screen>*

     If you want NetWare to close the screen automatically instead, use
     the `--autoclose' option to *Note `mysqld_safe': mysqld-safe.

   *  `--basedir=PATH'

     The path to the MySQL installation directory.

   *  `--core-file-size=SIZE'

     The size of the core file that *Note `mysqld': mysqld.  should be
     able to create. The option value is passed to `ulimit -c'.

   *  `--datadir=PATH'

     The path to the data directory.

   *  `--defaults-extra-file=PATH'

     The name of an option file to be read in addition to the usual
     option files. This must be the first option on the command line if
     it is used. As of MySQL 5.0.6, if the file does not exist or is
     otherwise inaccessible, the server will exit with an error.

   *  `--defaults-file=FILE_NAME'

     The name of an option file to be read instead of the usual option
     files. This must be the first option on the command line if it is
     used.

   *  `--ledir=PATH'

     If *Note `mysqld_safe': mysqld-safe. cannot find the server, use
     this option to indicate the path name to the directory where the
     server is located.

   *  `--log-error=FILE_NAME'

     Write the error log to the given file. See *Note error-log::.

   *  `--mysqld=PROG_NAME'

     The name of the server program (in the `ledir' directory) that you
     want to start.  This option is needed if you use the MySQL binary
     distribution but have the data directory outside of the binary
     distribution. If *Note `mysqld_safe': mysqld-safe.  cannot find
     the server, use the `--ledir' option to indicate the path name to
     the directory where the server is located.

   *  `--mysqld-version=SUFFIX'

     This option is similar to the `--mysqld' option, but you specify
     only the suffix for the server program name. The basename is
     assumed to be *Note `mysqld': mysqld. For example, if you use
     `--mysqld-version=debug', *Note `mysqld_safe': mysqld-safe. starts
     the *Note `mysqld-debug': mysqld. program in the `ledir'
     directory. If the argument to `--mysqld-version' is empty, *Note
     `mysqld_safe': mysqld-safe. uses *Note `mysqld': mysqld. in the
     `ledir' directory.

   *  `--nice=PRIORITY'

     Use the `nice' program to set the server's scheduling priority to
     the given value.

   *  `--no-defaults'

     Do not read any option files. This must be the first option on the
     command line if it is used.

   *  `--open-files-limit=COUNT'

     The number of files that *Note `mysqld': mysqld. should be able to
     open. The option value is passed to `ulimit -n'. Note that you
     need to start *Note `mysqld_safe': mysqld-safe. as `root' for this
     to work properly!

   *  `--pid-file=FILE_NAME'

     The path name of the process ID file.

   *  `--port=PORT_NUM'

     The port number that the server should use when listening for
     TCP/IP connections. The port number must be 1024 or higher unless
     the server is started by the `root' system user.

   *  `--skip-kill-mysqld'

     Do not try to kill stray *Note `mysqld': mysqld. processes at
     startup. This option works only on Linux.

   *  `--socket=PATH'

     The Unix socket file that the server should use when listening for
     local connections.

   *  `--timezone=TIMEZONE'

     Set the `TZ' time zone environment variable to the given option
     value. Consult your operating system documentation for legal time
     zone specification formats.

   *  `--user={USER_NAME|USER_ID}'

     Run the *Note `mysqld': mysqld. server as the user having the name
     USER_NAME or the numeric user ID USER_ID.  (`User' in this context
     refers to a system login account, not a MySQL user listed in the
     grant tables.)

If you execute *Note `mysqld_safe': mysqld-safe. with the
`--defaults-file' or `--defaults-extra-file' option to name an option
file, the option must be the first one given on the command line or the
option file will not be used. For example, this command will not use
the named option file:

     mysql> mysqld_safe --port=PORT_NUM --defaults-file=FILE_NAME

Instead, use the following command:

     mysql> mysqld_safe --defaults-file=FILE_NAME --port=PORT_NUM

The *Note `mysqld_safe': mysqld-safe. script is written so that it
normally can start a server that was installed from either a source or
a binary distribution of MySQL, even though these types of
distributions typically install the server in slightly different
locations. (See *Note installation-layouts::.)  *Note `mysqld_safe':
mysqld-safe. expects one of the following conditions to be true:

   * The server and databases can be found relative to the working
     directory (the directory from which *Note `mysqld_safe':
     mysqld-safe. is invoked). For binary distributions, *Note
     `mysqld_safe': mysqld-safe. looks under its working directory for
     `bin' and `data' directories. For source distributions, it looks
     for `libexec' and `var' directories. This condition should be met
     if you execute *Note `mysqld_safe': mysqld-safe. from your MySQL
     installation directory (for example, `/usr/local/mysql' for a
     binary distribution).

   * If the server and databases cannot be found relative to the
     working directory, *Note `mysqld_safe': mysqld-safe. attempts to
     locate them by absolute path names. Typical locations are
     `/usr/local/libexec' and `/usr/local/var'. The actual locations
     are determined from the values configured into the distribution at
     the time it was built. They should be correct if MySQL is
     installed in the location specified at configuration time.

Because *Note `mysqld_safe': mysqld-safe. tries to find the server and
databases relative to its own working directory, you can install a
binary distribution of MySQL anywhere, as long as you run *Note
`mysqld_safe': mysqld-safe. from the MySQL installation directory:

     shell> cd MYSQL_INSTALLATION_DIRECTORY
     shell> bin/mysqld_safe &

If *Note `mysqld_safe': mysqld-safe. fails, even when invoked from the
MySQL installation directory, you can specify the `--ledir' and
`--datadir' options to indicate the directories in which the server and
databases are located on your system.

Normally, you should not edit the *Note `mysqld_safe': mysqld-safe.
script. Instead, configure *Note `mysqld_safe': mysqld-safe. by using
command-line options or options in the `[mysqld_safe]' section of a
`my.cnf' option file. In rare cases, it might be necessary to edit
*Note `mysqld_safe': mysqld-safe. to get it to start the server
properly. However, if you do this, your modified version of *Note
`mysqld_safe': mysqld-safe. might be overwritten if you upgrade MySQL
in the future, so you should make a copy of your edited version that
you can reinstall.

On NetWare, *Note `mysqld_safe': mysqld-safe. is a NetWare Loadable
Module (NLM) that is ported from the original Unix shell script.  It
starts the server as follows:

  1. Runs a number of system and option checks.

  2. Runs a check on `MyISAM' tables.

  3. Provides a screen presence for the MySQL server.

  4. Starts *Note `mysqld': mysqld, monitors it, and restarts it if it
     terminates in error.

  5. Sends error messages from *Note `mysqld': mysqld. to the
     `HOST_NAME.err' file in the data directory.

  6. Sends *Note `mysqld_safe': mysqld-safe. screen output to the
     `HOST_NAME.safe' file in the data directory.


File: manual.info,  Node: mysql-server,  Next: mysqld-multi,  Prev: mysqld-safe,  Up: programs-server

5.3.3 `mysql.server' -- MySQL Server Startup Script
---------------------------------------------------

MySQL distributions on Unix include a script named *Note
`mysql.server': mysql-server. It can be used on systems such as Linux
and Solaris that use System V-style run directories to start and stop
system services. It is also used by the Mac OS X Startup Item for MySQL.

*Note `mysql.server': mysql-server. can be found in the `support-files'
directory under your MySQL installation directory or in a MySQL source
distribution.

If you use the Linux server RPM package (`MySQL-server-VERSION.rpm'),
the *Note `mysql.server': mysql-server. script will be installed in the
`/etc/init.d' directory with the name `mysql'. You need not install it
manually.  See *Note linux-installation-rpm::, for more information on
the Linux RPM packages.

Some vendors provide RPM packages that install a startup script under a
different name such as *Note `mysqld': mysqld.

If you install MySQL from a source distribution or using a binary
distribution format that does not install *Note `mysql.server':
mysql-server. automatically, you can install it manually. Instructions
are provided in *Note automatic-start::.

*Note `mysql.server': mysql-server. reads options from the
`[mysql.server]' and `[mysqld]' sections of option files. For backward
compatibility, it also reads `[mysql_server]' sections, although you
should rename such sections to `[mysql.server]' when using MySQL 5.0.

*Note `mysql.server': mysql-server. supports the following options.

   *  `--basedir=PATH'

     The path to the MySQL installation directory.

   *  `--datadir=PATH'

     The path to the MySQL data directory.

   *  `--pid-file=FILE_NAME'

     The path name of the file in which the server should write its
     process ID.

   *  `--service-startup-timeout=FILE_NAME'

     How long in seconds to wait for confirmation of server startup. If
     the server does not start within this time, *Note `mysql.server':
     mysql-server. exits with an error. The default value is 900. A
     value of 0 means not to wait at all for startup. Negative values
     mean to wait forever (no timeout). This option was added in MySQL
     5.0.40. Before that, a value of 900 is always used.

   *  `--use-mysqld_safe'

     Use *Note `mysqld_safe': mysqld-safe. to start the server. This is
     the default. This option was added in MySQL 5.0.4.

   *  `--use-manager'

     Use Instance Manager to start the server. This option was added in
     MySQL 5.0.4.

   *  `--user=USER_NAME'

     The login user name to use for running *Note `mysqld': mysqld.
     This option was added in MySQL 5.0.4.


File: manual.info,  Node: mysqld-multi,  Prev: mysql-server,  Up: programs-server

5.3.4 `mysqld_multi' -- Manage Multiple MySQL Servers
-----------------------------------------------------

*Note `mysqld_multi': mysqld-multi. is designed to manage several *Note
`mysqld': mysqld. processes that listen for connections on different
Unix socket files and TCP/IP ports. It can start or stop servers, or
report their current status. The MySQL Instance Manager is an
alternative means of managing multiple servers (see *Note
instance-manager::).

*Note `mysqld_multi': mysqld-multi. searches for groups named
`[mysqldN]' in `my.cnf' (or in the file named by the `--config-file'
option).  N can be any positive integer. This number is referred to in
the following discussion as the option group number, or GNR. Group
numbers distinguish option groups from one another and are used as
arguments to *Note `mysqld_multi': mysqld-multi. to specify which
servers you want to start, stop, or obtain a status report for.
Options listed in these groups are the same that you would use in the
`[mysqld]' group used for starting *Note `mysqld': mysqld. (See, for
example, *Note automatic-start::.) However, when using multiple
servers, it is necessary that each one use its own value for options
such as the Unix socket file and TCP/IP port number. For more
information on which options must be unique per server in a
multiple-server environment, see *Note multiple-servers::.

To invoke *Note `mysqld_multi': mysqld-multi, use the following syntax:

     shell> mysqld_multi [OPTIONS] {start|stop|report} [GNR[,GNR] ...]

`start', `stop', and `report' indicate which operation to perform.  You
can perform the designated operation for a single server or multiple
servers, depending on the GNR list that follows the option name. If
there is no list, *Note `mysqld_multi': mysqld-multi.  performs the
operation for all servers in the option file.

Each GNR value represents an option group number or range of group
numbers. The value should be the number at the end of the group name in
the option file. For example, the GNR for a group named `[mysqld17]' is
`17'. To specify a range of numbers, separate the first and last numbers
by a dash. The GNR value `10-13' represents groups `[mysqld10]' through
`[mysqld13]'. Multiple groups or group ranges can be specified on the
command line, separated by commas. There must be no whitespace
characters (spaces or tabs) in the GNR list; anything after a whitespace
character is ignored.

This command starts a single server using option group `[mysqld17]':

     shell> mysqld_multi start 17

This command stops several servers, using option groups `[mysqld8]' and
`[mysqld10]' through `[mysqld13]':

     shell> mysqld_multi stop 8,10-13

For an example of how you might set up an option file, use this command:

     shell> mysqld_multi --example

As of MySQL 5.0.42, *Note `mysqld_multi': mysqld-multi. searches for
option files as follows:

   *  With `--no-defaults', no option files are read.

   *  With `--defaults-file=FILE_NAME', only the named file is read.

   *  Otherwise, option files in the standard list of locations are
     read, including any file named by the
     `--defaults-extra-file=FILE_NAME' option, if one is given. (If the
     option is given multiple times, the last value is used.)

Before MySQL 5.0.42, the preceding options are not recognized.  Files
in the standard locations are read, and any file named by the
`--config-file=FILE_NAME' option, if one is given. A file named by
`--config-file' is read only for `[mysqldN]' option groups, not the
`[mysqld_multi]' group.

Option files read are searched for `[mysqld_multi]' and `[mysqldN]'
option groups. The `[mysqld_multi]' group can be used for options to
*Note `mysqld_multi': mysqld-multi. itself.  `[mysqldN]' groups can be
used for options passed to specific *Note `mysqld': mysqld. instances.

As of MySQL 5.0.82, the `[mysqld]' or `[mysqld_safe]' groups can be
used for common options read by all instances of *Note `mysqld':
mysqld. or *Note `mysqld_safe': mysqld-safe. You can specify a
`--defaults-file=FILE_NAME' option to use a different configuration
file for that instance, in which case the `[mysqld]' or `[mysqld_safe]'
groups from that file will be used for that instance. Before MySQL
5.0.82, some versions of *Note `mysqld_multi': mysqld-multi. pass the
`--no-defaults' options to instances, so these techniques are
inapplicable.

*Note `mysqld_multi': mysqld-multi. supports the following options.

   *  `--help'

     Display a help message and exit.

   *  `--config-file=FILE_NAME'

     As of MySQL 5.0.42, this option is deprecated. If given, it is
     treated the same way as `--defaults-extra-file', described earlier.
     `--config-file' is removed in MySQL 5.5.

     Before MySQL 5.0.42, this option specifies the name of an extra
     option file. It affects where *Note `mysqld_multi': mysqld-multi.
     looks for `[mysqldN]' option groups. Without this option, all
     options are read from the usual `my.cnf' file. The option does not
     affect where *Note `mysqld_multi': mysqld-multi. reads its own
     options, which are always taken from the `[mysqld_multi]' group in
     the usual `my.cnf' file.

   *  `--example'

     Display a sample option file.

   *  `--log=FILE_NAME'

     Specify the name of the log file. If the file exists, log output
     is appended to it.

   *  `--mysqladmin=PROG_NAME'

     The *Note `mysqladmin': mysqladmin. binary to be used to stop
     servers.

   *  `--mysqld=PROG_NAME'

     The *Note `mysqld': mysqld. binary to be used. Note that you can
     specify *Note `mysqld_safe': mysqld-safe. as the value for this
     option also. If you use *Note `mysqld_safe': mysqld-safe. to start
     the server, you can include the `mysqld' or `ledir' options in the
     corresponding `[mysqldN]' option group. These options indicate the
     name of the server that *Note `mysqld_safe': mysqld-safe. should
     start and the path name of the directory where the server is
     located. (See the descriptions for these options in *Note
     mysqld-safe::.) Example:

          [mysqld38]
          mysqld = mysqld-debug
          ledir  = /opt/local/mysql/libexec

   *  `--no-log'

     Print log information to `stdout' rather than to the log file. By
     default, output goes to the log file.

   *  `--password=PASSWORD'

     The password of the MySQL account to use when invoking *Note
     `mysqladmin': mysqladmin. Note that the password value is not
     optional for this option, unlike for other MySQL programs.

   *  `--silent'

     Silent mode; disable warnings.

   *  `--tcp-ip'

     Connect to each MySQL server through the TCP/IP port instead of
     the Unix socket file. (If a socket file is missing, the server
     might still be running, but accessible only through the TCP/IP
     port.) By default, connections are made using the Unix socket
     file. This option affects `stop' and `report' operations.

   *  `--user=USER_NAME'

     The user name of the MySQL account to use when invoking *Note
     `mysqladmin': mysqladmin.

   *  `--verbose'

     Be more verbose.

   *  `--version'

     Display version information and exit.

Some notes about *Note `mysqld_multi': mysqld-multi.:

   * *Most important*: Before using *Note `mysqld_multi': mysqld-multi.
     be sure that you understand the meanings of the options that are
     passed to the *Note `mysqld': mysqld. servers and _why_ you would
     want to have separate *Note `mysqld': mysqld. processes. Beware of
     the dangers of using multiple *Note `mysqld': mysqld. servers with
     the same data directory. Use separate data directories, unless you
     _know_ what you are doing. Starting multiple servers with the same
     data directory does _not_ give you extra performance in a threaded
     system. See *Note multiple-servers::.

   * *Important*:

     Make sure that the data directory for each server is fully
     accessible to the Unix account that the specific *Note `mysqld':
     mysqld. process is started as.  _Do not_ use the Unix ROOT account
     for this, unless you _know_ what you are doing. See *Note
     changing-mysql-user::.

   * Make sure that the MySQL account used for stopping the *Note
     `mysqld': mysqld. servers (with the *Note `mysqladmin':
     mysqladmin. program) has the same user name and password for each
     server. Also, make sure that the account has the `SHUTDOWN'
     privilege. If the servers that you want to manage have different
     user names or passwords for the administrative accounts, you might
     want to create an account on each server that has the same user
     name and password. For example, you might set up a common
     `multi_admin' account by executing the following commands for each
     server:

          shell> mysql -u root -S /tmp/mysql.sock -p
          Enter password:
          mysql> GRANT SHUTDOWN ON *.*
              -> TO 'multi_admin'@'localhost' IDENTIFIED BY 'multipass';

     See *Note privilege-system::. You have to do this for each *Note
     `mysqld': mysqld. server. Change the connection parameters
     appropriately when connecting to each one. Note that the host name
     part of the account name must permit you to connect as
     `multi_admin' from the host where you want to run *Note
     `mysqld_multi': mysqld-multi.

   * The Unix socket file and the TCP/IP port number must be different
     for every *Note `mysqld': mysqld.  (Alternatively, if the host has
     multiple network addresses, you can use `--bind-address' to cause
     different servers to listen to different interfaces.)

   * The `--pid-file' option is very important if you are using *Note
     `mysqld_safe': mysqld-safe. to start *Note `mysqld': mysqld. (for
     example, `--mysqld=mysqld_safe') Every *Note `mysqld': mysqld.
     should have its own process ID file. The advantage of using *Note
     `mysqld_safe': mysqld-safe. instead of *Note `mysqld': mysqld. is
     that *Note `mysqld_safe': mysqld-safe. monitors its *Note
     `mysqld': mysqld. process and restarts it if the process
     terminates due to a signal sent using `kill -9' or for other
     reasons, such as a segmentation fault. Please note that the *Note
     `mysqld_safe': mysqld-safe.  script might require that you start
     it from a certain place.  This means that you might have to change
     location to a certain directory before running *Note
     `mysqld_multi': mysqld-multi. If you have problems starting,
     please see the *Note `mysqld_safe': mysqld-safe.  script. Check
     especially the lines:

          ----------------------------------------------------------------
          MY_PWD=`pwd`
          # Check if we are starting this relative (for the binary release)
          if test -d $MY_PWD/data/mysql -a -f ./share/mysql/english/errmsg.sys -a \
           -x ./bin/mysqld
          ----------------------------------------------------------------

     The test performed by these lines should be successful, or you
     might encounter problems. See *Note mysqld-safe::.

   * You might want to use the `--user' option for *Note `mysqld':
     mysqld, but to do this you need to run the *Note `mysqld_multi':
     mysqld-multi. script as the Unix superuser (`root'). Having the
     option in the option file doesn't matter; you just get a warning if
     you are not the superuser and the *Note `mysqld': mysqld.
     processes are started under your own Unix account.

The following example shows how you might set up an option file for use
with *Note `mysqld_multi': mysqld-multi. The order in which the *Note
`mysqld': mysqld. programs are started or stopped depends on the order
in which they appear in the option file.  Group numbers need not form
an unbroken sequence. The first and fifth `[mysqldN]' groups were
intentionally omitted from the example to illustrate that you can have
`gaps' in the option file. This gives you more flexibility.

     # This file should probably be in your home dir (~/.my.cnf)
     # or /etc/my.cnf
     # Version 2.1 by Jani Tolonen

     [mysqld_multi]
     mysqld     = /usr/local/bin/mysqld_safe
     mysqladmin = /usr/local/bin/mysqladmin
     user       = multi_admin
     password   = multipass

     [mysqld2]
     socket     = /tmp/mysql.sock2
     port       = 3307
     pid-file   = /usr/local/mysql/var2/hostname.pid2
     datadir    = /usr/local/mysql/var2
     language   = /usr/local/share/mysql/english
     user       = john

     [mysqld3]
     socket     = /tmp/mysql.sock3
     port       = 3308
     pid-file   = /usr/local/mysql/var3/hostname.pid3
     datadir    = /usr/local/mysql/var3
     language   = /usr/local/share/mysql/swedish
     user       = monty

     [mysqld4]
     socket     = /tmp/mysql.sock4
     port       = 3309
     pid-file   = /usr/local/mysql/var4/hostname.pid4
     datadir    = /usr/local/mysql/var4
     language   = /usr/local/share/mysql/estonia
     user       = tonu

     [mysqld6]
     socket     = /tmp/mysql.sock6
     port       = 3311
     pid-file   = /usr/local/mysql/var6/hostname.pid6
     datadir    = /usr/local/mysql/var6
     language   = /usr/local/share/mysql/japanese
     user       = jani

See *Note option-files::.


File: manual.info,  Node: programs-installation,  Next: programs-client,  Prev: programs-server,  Up: programs

5.4 MySQL Installation-Related Programs
=======================================

* Menu:

* comp-err::                     `comp_err' --- Compile MySQL Error Message File
* make-win-bin-dist::            `make_win_bin_dist' --- Package MySQL Distribution as Zip Archive
* make-win-src-distribution::    `make_win_src_distribution' --- Create Source Distribution for Windows
* mysqlbug::                     `mysqlbug' --- Generate Bug Report
* mysql-fix-privilege-tables::   `mysql_fix_privilege_tables' --- Upgrade MySQL System Tables
* mysql-install-db::             `mysql_install_db' --- Initialize MySQL Data Directory
* mysql-secure-installation::    `mysql_secure_installation' --- Improve MySQL Installation Security
* mysql-tzinfo-to-sql::          `mysql_tzinfo_to_sql' --- Load the Time Zone Tables
* mysql-upgrade::                `mysql_upgrade' --- Check Tables for MySQL Upgrade

The programs in this section are used when installing or upgrading
MySQL.


File: manual.info,  Node: comp-err,  Next: make-win-bin-dist,  Prev: programs-installation,  Up: programs-installation

5.4.1 `comp_err' -- Compile MySQL Error Message File
----------------------------------------------------

*Note `comp_err': comp-err. creates the `errmsg.sys' file that is used
by *Note `mysqld': mysqld. to determine the error messages to display
for different error codes. *Note `comp_err': comp-err.  normally is run
automatically when MySQL is built. It compiles the `errmsg.sys' file
from the plaintext file located at `sql/share/errmsg.txt' in MySQL
source distributions.

*Note `comp_err': comp-err. also generates `mysqld_error.h',
`mysqld_ername.h', and `sql_state.h' header files.

For more information about how error messages are defined, see the
MySQL Internals Manual, available at
`http://forge.mysql.com/wiki/MySQL_Internals'.

Invoke *Note `comp_err': comp-err. like this:

     shell> comp_err [OPTIONS]

*Note `comp_err': comp-err. supports the following options.

   *  `--help', `-?'

     Display a help message and exit.

   *  `--charset=PATH', `-C PATH'

     The character set directory. The default is
     `../sql/share/charsets'.

   *  `--debug=DEBUG_OPTIONS', `-# DEBUG_OPTIONS'

     Write a debugging log. A typical DEBUG_OPTIONS string is
     `'d:t:O,FILE_NAME''.  The default is `'d:t:O,/tmp/comp_err.trace''.

   *  `--debug-info', `-T'

     Print some debugging information when the program exits.

   *  `--header_file=FILE_NAME', `-H FILE_NAME'

     The name of the error header file. The default is `mysqld_error.h'.

   *  `--in_file=FILE_NAME', `-F FILE_NAME'

     The name of the input file. The default is
     `../sql/share/errmsg.txt'.

   *  `--name_file=FILE_NAME', `-N FILE_NAME'

     The name of the error name file. The default is `mysqld_ername.h'.

   *  `--out_dir=PATH', `-D PATH'

     The name of the output base directory. The default is
     `../sql/share/'.

   *  `--out_file=FILE_NAME', `-O FILE_NAME'

     The name of the output file. The default is `errmsg.sys'.

   *  `--statefile=FILE_NAME', `-S FILE_NAME'

     The name for the SQLSTATE header file. The default is
     `sql_state.h'.

   *  `--version', `-V'

     Display version information and exit.


File: manual.info,  Node: make-win-bin-dist,  Next: make-win-src-distribution,  Prev: comp-err,  Up: programs-installation

5.4.2 `make_win_bin_dist' -- Package MySQL Distribution as Zip Archive
----------------------------------------------------------------------

This script is used on Windows after building a MySQL distribution from
source to create executable programs. It packages the binaries and
support files into a Zip archive that can be unpacked at the location
where you want to install MySQL.

*Note `make_win_bin_dist': make-win-bin-dist. is a shell script, so you
must have Cygwin installed to use it.

This program's use is subject to change. Currently, you invoke it as
follows from the root directory of your source distribution:

     shell> make_win_bin_dist [OPTIONS] PACKAGE_BASENAME [COPY_DEF ...]

The PACKAGE_BASENAME argument provides the basename for the resulting
Zip archive. This name will be the name of the directory that results
from unpacking the archive.

Because you might want to include files of directories from other
builds, you can instruct this script to copy them in for you, using
COPY_DEF arguments, which have the form RELATIVE_DEST_NAME=SOURCE_NAME.

Example:

     bin/mysqld-max.exe=../my-max-build/sql/release/mysqld.exe

If you specify a directory, the entire directory will be copied.

*Note `make_win_bin_dist': make-win-bin-dist. supports the following
options.

   *  `--debug'

     Pack the debug binaries and produce an error if they were not
     built.

   *  `--embedded'

     Pack the embedded server and produce an error if it was not built.
     The default is to pack it if it was built.

   *  `--exe-suffix=SUFFIX'

     Add a suffix to the basename of the *Note `mysql': mysql.  binary.
     For example, a suffix of `-abc' produces a binary named
     `mysqld-abc.exe'.

   *  `--no-debug'

     Do not pack the debug binaries even if they were built.

   *  `--no-embedded'

     Do not pack the embedded server even if it was built.

   *  `--only-debug'

     Use this option when the target for this build was `Debug', and
     you just want to replace the normal binaries with debug versions
     (that is, do not use separate `debug' directories).


File: manual.info,  Node: make-win-src-distribution,  Next: mysqlbug,  Prev: make-win-bin-dist,  Up: programs-installation

5.4.3 `make_win_src_distribution' -- Create Source Distribution for Windows
---------------------------------------------------------------------------

*Note `make_win_src_distribution': make-win-src-distribution. creates a
Windows source package to be used on Windows systems. It is used after
you configure and build the source distribution on a Unix or Unix-like
system so that you have a server binary to work with.  (See the
instructions at *Note windows-sourcetree-build::.)

Invoke *Note `make_win_src_distribution': make-win-src-distribution.
like this from the top-level directory of a MySQL source distribution:

     shell> make_win_src_distribution [OPTIONS]

*Note `make_win_src_distribution': make-win-src-distribution.
understands the following options:

   *  `--help'

     Display a help message and exit.

   *  `--debug'

     Print information about script operations; do not create a package.

   *  `--dirname'

     Directory name to copy files (intermediate).

   *  `--silent'

     Do not print verbose list of files processed.

   *  `--suffix'

     The suffix name for the package.

   *  `--tar'

     Create a `.tar.gz' package instead of a `.zip' package.

     By default, *Note `make_win_src_distribution':
     make-win-src-distribution.  creates a Zip-format archive with the
     name `mysql-VERSION-win-src.zip', where VERSION represents the
     version of your MySQL source tree.

   *  `--tmp'

     Specify the temporary location.


File: manual.info,  Node: mysqlbug,  Next: mysql-fix-privilege-tables,  Prev: make-win-src-distribution,  Up: programs-installation

5.4.4 `mysqlbug' -- Generate Bug Report
---------------------------------------

This program enables you to generate a bug report and send it to Oracle
Corporation. It is a shell script and runs on Unix.

The normal way to report bugs is to visit `http://bugs.mysql.com/',
which is the address for our bugs database. This database is public and
can be browsed and searched by anyone. If you log in to the system, you
can enter new reports. If you have no Web access, you can generate a
bug report by using the *Note `mysqlbug': mysqlbug. script.

*Note `mysqlbug': mysqlbug. helps you generate a report by determining
much of the following information automatically, but if something
important is missing, please include it with your message. *Note
`mysqlbug': mysqlbug. can be found in the `scripts' directory (source
distribution) and in the `bin' directory under your MySQL installation
directory (binary distribution).

Invoke *Note `mysqlbug': mysqlbug. without arguments:

     shell> mysqlbug

The script will place you in an editor with a copy of the report to be
sent. Edit the lines near the beginning that indicate the nature of the
problem. Then write the file to save your changes, quit the editor, and
*Note `mysqlbug': mysqlbug. will send the report by email.


File: manual.info,  Node: mysql-fix-privilege-tables,  Next: mysql-install-db,  Prev: mysqlbug,  Up: programs-installation

5.4.5 `mysql_fix_privilege_tables' -- Upgrade MySQL System Tables
-----------------------------------------------------------------

Some releases of MySQL introduce changes to the structure of the system
tables in the `mysql' database to add new privileges or support new
features. When you update to a new version of MySQL, you should update
your system tables as well to make sure that their structure is up to
date. Otherwise, there might be capabilities that you cannot take
advantage of.

*Note `mysql_fix_privilege_tables': mysql-fix-privilege-tables. is an
older script that previously was used to uprade the system tables in the
`mysql' database after a MySQL upgrade.

*Note*:

As of MySQL 5.0.19, *Note `mysql_fix_privilege_tables':
mysql-fix-privilege-tables. is superseded by *Note `mysql_upgrade':
mysql-upgrade, which should be used instead. See *Note mysql-upgrade::.

Before running *Note `mysql_fix_privilege_tables':
mysql-fix-privilege-tables, make a backup of your `mysql' database.

On Unix or Unix-like systems, update the system tables by running the
*Note `mysql_fix_privilege_tables': mysql-fix-privilege-tables.  script:

     shell> mysql_fix_privilege_tables

You must run this script while the server is running. It attempts to
connect to the server running on the local host as `root'. If your
`root' account requires a password, indicate the password on the
command line like this:

     shell> mysql_fix_privilege_tables --password=ROOT_PASSWORD

The *Note `mysql_fix_privilege_tables': mysql-fix-privilege-tables.
script performs any actions necessary to convert your system tables to
the current format. You might see some `Duplicate column name' warnings
as it runs; you can ignore them.

After running the script, stop the server and restart it so that any
changes made to the system tables take effect.

On Windows systems, MySQL distributions include a
`mysql_fix_privilege_tables.sql' SQL script that you can run using the
*Note `mysql': mysql. client. For example, if your MySQL installation
is located at `C:\Program Files\MySQL\MySQL Server 5.0', the commands
look like this:

     C:\> cd "C:\Program Files\MySQL\MySQL Server 5.0"
     C:\> bin\mysql -u root -p mysql
     mysql> SOURCE share/mysql_fix_privilege_tables.sql

*Note*:

Prior to version 5.0.38, this script is found in the `scripts'
directory.

The *Note `mysql': mysql. command will prompt you for the `root'
password; enter it when prompted.

If your installation is located in some other directory, adjust the
path names appropriately.

As with the Unix procedure, you might see some `Duplicate column name'
warnings as *Note `mysql': mysql. processes the statements in the
`mysql_fix_privilege_tables.sql' script; you can ignore them.

After running the script, stop the server and restart it.


File: manual.info,  Node: mysql-install-db,  Next: mysql-secure-installation,  Prev: mysql-fix-privilege-tables,  Up: programs-installation

5.4.6 `mysql_install_db' -- Initialize MySQL Data Directory
-----------------------------------------------------------

*Note `mysql_install_db': mysql-install-db. initializes the MySQL data
directory and creates the system tables that it contains, if they do
not exist.

To invoke *Note `mysql_install_db': mysql-install-db, use the following
syntax:

     shell> mysql_install_db [OPTIONS]

Because the MySQL server, *Note `mysqld': mysqld, needs to access the
data directory when it runs later, you should either run *Note
`mysql_install_db': mysql-install-db. from the same account that will
be used for running *Note `mysqld': mysqld. or run it as `root' and use
the `--user' option to indicate the user name that *Note `mysqld':
mysqld. will run as. It might be necessary to specify other options
such as `--basedir' or `--datadir' if *Note `mysql_install_db':
mysql-install-db. does not use the correct locations for the
installation directory or data directory. For example:

     shell> bin/mysql_install_db --user=mysql \
              --basedir=/opt/mysql/mysql \
              --datadir=/opt/mysql/mysql/data

*Note `mysql_install_db': mysql-install-db. needs to invoke *Note
`mysqld': mysqld. with the `--bootstrap' and `--skip-grant-tables'
options. If MySQL was configured with the `DISABLE_GRANT_OPTIONS'
(http://dev.mysql.com/doc/refman/5.5/en/source-configuration-options.html#option_cmake_disable_grant_options)
compiler flag, `--bootstrap' and `--skip-grant-tables' will be disabled
(see *Note source-configuration-options::).  To handle this, set the
`MYSQLD_BOOTSTRAP' environment variable to the full path name of a
server that has all options enabled. *Note `mysql_install_db':
mysql-install-db. will use that server.

*Note `mysql_install_db': mysql-install-db. supports the following
options, which can be specified on the command line or in the
`[mysql_install_db]' and (if they are common to *Note `mysqld':
mysqld.) `[mysqld]' groups of an option file. For information about
option files, see *Note option-files::.

   *  `--basedir=PATH'

     The path to the MySQL installation directory.

   *  `--force'

     Cause *Note `mysql_install_db': mysql-install-db. to run even if
     DNS does not work. In that case, grant table entries that normally
     use host names will use IP addresses.

   *  `--datadir=PATH', `--ldata=PATH'

     The path to the MySQL data directory.

   *  `--rpm'

     For internal use. This option is used by RPM files during the
     MySQL installation process.

   *  `--skip-name-resolve'

     Use IP addresses rather than host names when creating grant table
     entries. This option can be useful if your DNS does not work.

   *  `--srcdir=PATH'

     For internal use. The directory under which *Note
     `mysql_install_db': mysql-install-db. looks for support files such
     as the error message file and the file for populating the help
     tables. This option was added in MySQL 5.0.32.

   *  `--user=USER_NAME'

     The login user name to use for running *Note `mysqld': mysqld.
     Files and directories created by *Note `mysqld': mysqld. will be
     owned by this user. You must be `root' to use this option. By
     default, *Note `mysqld': mysqld. runs using your current login
     name and files and directories that it creates will be owned by
     you.

   *  `--verbose'

     Verbose mode. Print more information about what the program does.

   *  `--windows'

     For internal use. This option is used for creating Windows
     distributions.


File: manual.info,  Node: mysql-secure-installation,  Next: mysql-tzinfo-to-sql,  Prev: mysql-install-db,  Up: programs-installation

5.4.7 `mysql_secure_installation' -- Improve MySQL Installation Security
------------------------------------------------------------------------

This program enables you to improve the security of your MySQL
installation in the following ways:

   * You can set a password for `root' accounts.

   * You can remove `root' accounts that are accessible from outside
     the local host.

   * You can remove anonymous-user accounts.

   * You can remove the `test' database (which by default can be
     accessed by all users, even anonymous users), and privileges that
     permit anyone to access databases with names that start with
     `test_'.

*Note `mysql_secure_installation': mysql-secure-installation. helps you
implement security recommendations similar to those described at *Note
default-privileges::.

Invoke *Note `mysql_secure_installation': mysql-secure-installation.
without arguments:

     shell> mysql_secure_installation

The script will prompt you to determine which actions to perform.

*Note `mysql_secure_installation': mysql-secure-installation. is not
available on Windows.


File: manual.info,  Node: mysql-tzinfo-to-sql,  Next: mysql-upgrade,  Prev: mysql-secure-installation,  Up: programs-installation

5.4.8 `mysql_tzinfo_to_sql' -- Load the Time Zone Tables
--------------------------------------------------------

The *Note `mysql_tzinfo_to_sql': mysql-tzinfo-to-sql. program loads the
time zone tables in the `mysql' database. It is used on systems that
have a _zoneinfo_ database (the set of files describing time zones).
Examples of such systems are Linux, FreeBSD, Solaris, and Mac OS X. One
likely location for these files is the `/usr/share/zoneinfo' directory
(`/usr/share/lib/zoneinfo' on Solaris). If your system does not have a
zoneinfo database, you can use the downloadable package described in
*Note time-zone-support::.

*Note `mysql_tzinfo_to_sql': mysql-tzinfo-to-sql. can be invoked several
ways:

     shell> mysql_tzinfo_to_sql TZ_DIR
     shell> mysql_tzinfo_to_sql TZ_FILE TZ_NAME
     shell> mysql_tzinfo_to_sql --leap TZ_FILE

For the first invocation syntax, pass the zoneinfo directory path name
to *Note `mysql_tzinfo_to_sql': mysql-tzinfo-to-sql. and send the
output into the *Note `mysql': mysql. program. For example:

     shell> mysql_tzinfo_to_sql /usr/share/zoneinfo | mysql -u root mysql

*Note `mysql_tzinfo_to_sql': mysql-tzinfo-to-sql. reads your system's
time zone files and generates SQL statements from them.  *Note `mysql':
mysql. processes those statements to load the time zone tables.

The second syntax causes *Note `mysql_tzinfo_to_sql':
mysql-tzinfo-to-sql.  to load a single time zone file TZ_FILE that
corresponds to a time zone name TZ_NAME:

     shell> mysql_tzinfo_to_sql TZ_FILE TZ_NAME | mysql -u root mysql

If your time zone needs to account for leap seconds, invoke *Note
`mysql_tzinfo_to_sql': mysql-tzinfo-to-sql. using the third syntax,
which initializes the leap second information.  TZ_FILE is the name of
your time zone file:

     shell> mysql_tzinfo_to_sql --leap TZ_FILE | mysql -u root mysql

After running *Note `mysql_tzinfo_to_sql': mysql-tzinfo-to-sql, it is
best to restart the server so that it does not continue to use any
previously cached time zone data.


File: manual.info,  Node: mysql-upgrade,  Prev: mysql-tzinfo-to-sql,  Up: programs-installation

5.4.9 `mysql_upgrade' -- Check Tables for MySQL Upgrade
-------------------------------------------------------

*Note `mysql_upgrade': mysql-upgrade. examines all tables in all
databases for incompatibilities with the current version of MySQL
Server. *Note `mysql_upgrade': mysql-upgrade. also upgrades the system
tables so that you can take advantage of new privileges or capabilities
that might have been added.

*Note `mysql_upgrade': mysql-upgrade. should be executed each time you
upgrade MySQL. It supersedes the older *Note
`mysql_fix_privilege_tables': mysql-fix-privilege-tables. script, which
should no longer be used.

If *Note `mysql_upgrade': mysql-upgrade. finds that a table has a
possible incompatibility, it performs a table check and, if problems
are found, attempts a table repair. If the table cannot be repaired,
see *Note rebuilding-tables:: for manual table repair strategies.

*Caution*:

You should always back up your current MySQL installation _before_
performing an upgrade. See *Note backup-methods::.

Some upgrade incompatibilities may require special handling before you
upgrade your MySQL installation and run *Note `mysql_upgrade':
mysql-upgrade. See *Note upgrading::, for instructions on determining
whether any such incompatibilities apply to your installation and how
to handle them.

To use *Note `mysql_upgrade': mysql-upgrade, make sure that the server
is running, and then invoke it like this:

     shell> mysql_upgrade [OPTIONS]

After running *Note `mysql_upgrade': mysql-upgrade, stop the server and
restart it so that any changes made to the system tables take effect.

*Note `mysql_upgrade': mysql-upgrade. executes the following commands
to check and repair tables and to upgrade the system tables:

     mysqlcheck --all-databases --check-upgrade --auto-repair
     mysql < FIX_PRIV_TABLES

Notes about the preceding commands:

   * Because *Note `mysql_upgrade': mysql-upgrade. invokes *Note
     `mysqlcheck': mysqlcheck. with the `--all-databases' option, it
     processes all tables in all databases, which might take a long
     time to complete. Each table is locked and therefore unavailable
     to other sessions while it is being processed.  Check and repair
     operations can be time-consuming, particularly for large tables.

   * For details about what checks the `--check-upgrade' option
     entails, see the description of the `FOR UPGRADE' option of the
     *Note `CHECK TABLE': check-table. statement (see *Note
     check-table::).

   * FIX_PRIV_TABLES represents a script generated internally by *Note
     `mysql_upgrade': mysql-upgrade. that contains SQL statements to
     upgrade the tables in the `mysql' database.

All checked and repaired tables are marked with the current MySQL
version number. This ensures that next time you run *Note
`mysql_upgrade': mysql-upgrade. with the same version of the server, it
can tell whether there is any need to check or repair the table again.

*Note `mysql_upgrade': mysql-upgrade. also saves the MySQL version
number in a file named `mysql_upgrade_info' in the data directory. This
is used to quickly check whether all tables have been checked for this
release so that table-checking can be skipped. To ignore this file and
perform the check regardless, use the `--force' option.

If you install MySQL from RPM packages on Linux, you must install the
server and client RPMs.  *Note `mysql_upgrade': mysql-upgrade. is
included in the server RPM but requires the client RPM because the
latter includes *Note `mysqlcheck': mysqlcheck. (See *Note
linux-installation-rpm::.)

In MySQL 5.0.19, `mysql_upgrade ' was added as a shell script and
worked only for Unix systems. As of MySQL 5.0.25, *Note
`mysql_upgrade': mysql-upgrade. is an executable binary and is
available on all systems.

*Note `mysql_upgrade': mysql-upgrade. does not upgrade the contents of
the help tables. For upgrade instructions, see *Note
server-side-help-support::.

*Note `mysql_upgrade': mysql-upgrade. supports the following options,
which can be specified on the command line or in the `[mysql_upgrade]'
and `[client]' groups of an option file. Other options are passed to
*Note `mysqlcheck': mysqlcheck. For example, it might be necessary to
specify the `--password[=PASSWORD]' option. *Note `mysql_upgrade':
mysql-upgrade. also supports the options for processing option files
described at *Note option-file-options::.

   *  `--help'

     Display a short help message and exit.

   *  `--basedir=PATH'

     The path to the MySQL installation directory. This option is
     accepted for backward compatibility but ignored.

   *  `--datadir=PATH'

     The path to the data directory. This option is accepted for
     backward compatibility but ignored.

   *  `--force'

     Ignore the `mysql_upgrade_info' file and force execution of *Note
     `mysqlcheck': mysqlcheck. even if *Note `mysql_upgrade':
     mysql-upgrade. has already been executed for the current version
     of MySQL.

   *  `--tmpdir=PATH', `-t PATH'

     The path name of the directory to use for creating temporary
     files. This option was added in MySQL 5.0.62.

   *  `--user=USER_NAME', `-u USER_NAME'

     The MySQL user name to use when connecting to the server.  The
     default user name is `root'.

   *  `--verbose'

     Verbose mode. Print more information about what the program does.


File: manual.info,  Node: programs-client,  Next: programs-admin-utils,  Prev: programs-installation,  Up: programs

5.5 MySQL Client Programs
=========================

* Menu:

* mysql::                        `mysql' --- The MySQL Command-Line Tool
* mysqladmin::                   `mysqladmin' --- Client for Administering a MySQL Server
* mysqlcheck::                   `mysqlcheck' --- A Table Maintenance Program
* mysqldump::                    `mysqldump' --- A Database Backup Program
* mysqlimport::                  `mysqlimport' --- A Data Import Program
* mysqlshow::                    `mysqlshow' --- Display Database, Table, and Column Information

This section describes client programs that connect to the MySQL server.


File: manual.info,  Node: mysql,  Next: mysqladmin,  Prev: programs-client,  Up: programs-client

5.5.1 `mysql' -- The MySQL Command-Line Tool
--------------------------------------------

* Menu:

* mysql-command-options::        `mysql' Options
* mysql-commands::               `mysql' Commands
* mysql-history-file::           `mysql' History File
* mysql-server-side-help::       `mysql' Server-Side Help
* batch-commands::               Executing SQL Statements from a Text File
* mysql-tips::                   `mysql' Tips

*Note `mysql': mysql. is a simple SQL shell (with GNU `readline'
capabilities). It supports interactive and noninteractive use. When
used interactively, query results are presented in an ASCII-table
format. When used noninteractively (for example, as a filter), the
result is presented in tab-separated format. The output format can be
changed using command options.

If you have problems due to insufficient memory for large result sets,
use the `--quick' option. This forces *Note `mysql': mysql. to retrieve
results from the server a row at a time rather than retrieving the
entire result set and buffering it in memory before displaying it. This
is done by returning the result set using the *Note
`mysql_use_result()': mysql-use-result. C API function in the
client/server library rather than *Note `mysql_store_result()':
mysql-store-result.

Using *Note `mysql': mysql. is very easy. Invoke it from the prompt of
your command interpreter as follows:

     shell> mysql DB_NAME

Or:

     shell> mysql --user=USER_NAME --password=YOUR_PASSWORD DB_NAME

Then type an SQL statement, end it with ``;'', `\g', or `\G' and press
Enter.

As of MySQL 5.0.25, typing Control+C causes *Note `mysql': mysql. to
attempt to kill the current statement. If this cannot be done, or
Control+C is typed again before the statement is killed, *Note `mysql':
mysql. exits.  Previously, Control+C caused *Note `mysql': mysql. to
exit in all cases.

You can execute SQL statements in a script file (batch file) like this:

     shell> mysql DB_NAME < SCRIPT.SQL > OUTPUT.TAB

On Unix, the *Note `mysql': mysql. client writes a record of executed
statements to a history file. See *Note mysql-history-file::.


File: manual.info,  Node: mysql-command-options,  Next: mysql-commands,  Prev: mysql,  Up: mysql

5.5.1.1 `mysql' Options
.......................

*Note `mysql': mysql. supports the following options, which can be
specified on the command line or in the `[mysql]' and `[client]' groups
of an option file. *Note `mysql': mysql. also supports the options for
processing option files described at *Note option-file-options::.

*`mysql' Options*

Format      Option File Description                   IntroductionDeprecatedRemoved
-auto-rehashauto-rehash Enable automatic rehashing                    
-batch      batch       Don't use history file                        
-character-sets-dir=pathcharacter-sets-dirSet the default character set                 
-column-namescolumn-namesWrite column names in results                 
-comments   comments    Whether to retain or strip    5.0.52          
                        comments in statements sent                   
                        to the  server                                
-compress   compress    Compress all information                      
                        sent between the client and                   
                        the server                                    
-connect_timeout=valueconnect_timeoutThe number of seconds before                  
                        connection timeout                            
-database=dbnamedatabase    The database to use                           
-debug[=debug_options]debug       Write a debugging log                         
-debug-info debug-info  Print debugging information,                  
                        memory and CPU statistics                     
                        when the  program exits                       
-default-character-set=charset_namedefault-character-setUse charset_name as the                       
                        default character set                         
-delimiter=strdelimiter   Set the statement delimiter                   
-execute=statementexecute     Execute the statement and                     
                        quit                                          
-force      force       Continue even if an SQL                       
                        error occurs                                  
-help                   Display help message and exit                 
-host=host_namehost        Connect to the MySQL server                   
                        on the given host                             
-html       html        Produce HTML output                           
-ignore-spacesignore-spacesIgnore spaces after function                  
                        names                                         
-line-numbersline-numbersWrite line numbers for errors                 
-local-infile[={0|1}]local-infileEnable or disable for LOCAL                   
                        capability for LOAD DATA                      
                        INFILE                                        
-max_allowed_packet=valuemax_allowed_packetThe maximum packet length to                  
                        send to or receive from the                   
                        server                                        
-max_join_size=valuemax_join_sizeThe automatic limit for rows                  
                        in a join when using                          
                        -safe-updates                                 
-named-commandsnamed-commandsEnable named mysql commands                   
-net_buffer_length=valuenet_buffer_lengthThe buffer size for TCP/IP                    
                        and socket communication                      
-no-auto-rehash            Disable automatic rehashing                   
-no-beep    no-beep     Do not beep when errors occur                 
-no-named-commandsno-named-commandsDisable named mysql commands                  
-no-pager   no-pager    Deprecated form of                            
                        -skip-pager                                   
-no-tee     no-tee      Do not copy output to a file                  
-one-databaseone-databaseIgnore statements except                      
                        those for the default                         
                        database named on  the                        
                        command line                                  
-pager[=command]pager       Use the given command for                     
                        paging query output                           
-password[=password]password    The password to use when                      
                        connecting to the server                      
-port=port_numport        The TCP/IP port number to                     
                        use for the connection                        
-prompt=format_strprompt      Set the prompt to the                         
                        specified format                              
-protocol=typeprotocol    The connection protocol to                    
                        use                                           
-quick      quick       Do not cache each query                       
                        result                                        
-raw        raw         Write column values without                   
                        escape conversion                             
-reconnect  reconnect   If the connection to the                      
                        server is lost,                               
                        automatically try to                          
                        reconnect                                     
-safe-updatessafe-updatesAllow only UPDATE and DELETE                  
                        statements that specify key                   
                        values                                        
-secure-authsecure-auth Do not send passwords to the                  
                        server in old (pre-4.1.1)                     
                        format                                        
-select_limit=valueselect_limitThe automatic limit for                       
                        SELECT statements when using                  
                        -safe-updates                                 
-show-warningsshow-warningsShow warnings after each      5.0.6           
                        statement if there are any                    
-sigint-ignoresigint-ignoreIgnore SIGINT signals                         
                        (typically the result of                      
                        typing Control+C)                             
-silent     silent      Silent mode                                   
-skip-auto-rehashskip-auto-rehashDisable automatic rehashing                   
-skip-column-namesskip-column-namesDo not write column names in                  
                        results                                       
-skip-line-numbersskip-line-numbersSkip line numbers for errors                  
-skip-named-commandsskip-named-commandsDisable named mysql commands                  
-skip-pager skip-pager  Disable paging                                
-skip-reconnectskip-reconnectDisable reconnecting                          
-socket=pathsocket      For connections to localhost                  
-ssl-ca=file_namessl-ca      The path to a file that                       
                        contains a list of trusted                    
                        SSL CAs                                       
-ssl-capath=dir_namessl-capath  The path to a directory that                  
                        contains trusted SSL CA                       
                        certificates  in PEM format                   
-ssl-cert=file_namessl-cert    The name of the SSL                           
                        certificate file to use for                   
                        establishing a  secure                        
                        connection                                    
-ssl-cipher=cipher_listssl-cipher  A list of allowable ciphers                   
                        to use for SSL encryption                     
-ssl-key=file_namessl-key     The name of the SSL key file                  
                        to use for establishing a                     
                        secure  connection                            
-ssl-verify-server-certssl-verify-server-certThe server's Common Name                      
                        value in its certificate is                   
                        verified  against the host                    
                        name used when connecting to                  
                        the server                                    
-table      table       Display output in tabular                     
                        format                                        
-tee=file_nametee         Append a copy of output to                    
                        the given file                                
-unbuffered unbuffered  Flush the buffer after each                   
                        query                                         
-user=user_nameuser        The MySQL user name to use                    
                        when connecting to the server                 
-verbose                Verbose mode                                  
-version                Display version information                   
                        and exit                                      
-vertical   vertical    Print query output rows                       
                        vertically (one line per                      
                        column value)                                 
-wait       wait        If the connection cannot be                   
                        established, wait and retry                   
                        instead of  aborting                          
-xml        xml         Produce XML output                            

   *  `--help', `-?'

     Display a help message and exit.

   *  `--auto-rehash'

     Enable automatic rehashing. This option is on by default, which
     enables database, table, and column name completion.  Use
     `--disable-auto-rehash' to disable rehashing. That causes *Note
     `mysql': mysql.  to start faster, but you must issue the `rehash'
     command if you want to use name completion.

     To complete a name, enter the first part and press Tab. If the
     name is unambiguous, *Note `mysql': mysql. completes it.
     Otherwise, you can press Tab again to see the possible names that
     begin with what you have typed so far. Completion does not occur
     if there is no default database.

   *  `--batch', `-B'

     Print results using tab as the column separator, with each row on
     a new line. With this option, *Note `mysql': mysql. does not use
     the history file.

     Batch mode results in nontabular output format and escaping of
     special characters. Escaping may be disabled by using raw mode;
     see the description for the `--raw' option.

   *  `--character-sets-dir=PATH'

     The directory where character sets are installed. See *Note
     charset-configuration::.

   *  `--column-names'

     Write column names in results.

   *  `--comments', `-c'

     Whether to preserve comments in statements sent to the server. The
     default is -skip-comments (discard comments), enable with
     -comments (preserve comments). This option was added in MySQL
     5.0.52.

   *  `--compress', `-C'

     Compress all information sent between the client and the server if
     both support compression.

   *  `--database=DB_NAME', `-D DB_NAME'

     The database to use. This is useful primarily in an option file.

   *  `--debug[=DEBUG_OPTIONS]', `-# [DEBUG_OPTIONS]'

     Write a debugging log. A typical DEBUG_OPTIONS string is
     `'d:t:o,FILE_NAME''.  The default is `'d:t:o,/tmp/mysql.trace''.

   *  `--debug-info', `-T'

     Print some debugging information when the program exits.

   *  `--default-character-set=CHARSET_NAME'

     Use CHARSET_NAME as the default character set for the client and
     connection.

     A common issue that can occur when the operating system uses
     `utf8' or another multi-byte character set is that output from the
     *Note `mysql': mysql. client is formatted incorrectly, due to the
     fact that the MySQL client uses the `latin1' character set by
     default.  You can usually fix such issues by using this option to
     force the client to use the system character set instead.

     See *Note charset-configuration::, for more information.

   *  `--delimiter=STR'

     Set the statement delimiter. The default is the semicolon
     character (``;'').

   *  `--disable-named-commands'

     Disable named commands. Use the `\*' form only, or use named
     commands only at the beginning of a line ending with a semicolon
     (``;'').  *Note `mysql': mysql. starts with this option _enabled_
     by default. However, even with this option, long-format commands
     still work from the first line. See *Note mysql-commands::.

   *  `--execute=STATEMENT', `-e STATEMENT'

     Execute the statement and quit. The default output format is like
     that produced with `--batch'. See *Note command-line-options::,
     for some examples.  With this option, *Note `mysql': mysql. does
     not use the history file.

   *  `--force', `-f'

     Continue even if an SQL error occurs.

   *  `--host=HOST_NAME', `-h HOST_NAME'

     Connect to the MySQL server on the given host.

   *  `--html', `-H'

     Produce HTML output.

   *  `--ignore-spaces', `-i'

     Ignore spaces after function names. The effect of this is
     described in the discussion for the `IGNORE_SPACE' SQL mode (see
     *Note server-sql-mode::).

   *  `--line-numbers'

     Write line numbers for errors. Disable this with
     `--skip-line-numbers'.

   *  `--local-infile[={0|1}]'

     Enable or disable `LOCAL' capability for *Note `LOAD DATA INFILE':
     load-data. With no value, the option enables `LOCAL'. The option
     may be given as `--local-infile=0' or `--local-infile=1' to
     explicitly disable or enable `LOCAL'. Enabling `LOCAL' has no
     effect if the server does not also support it.

   *  `--named-commands', `-G'

     Enable named *Note `mysql': mysql. commands. Long-format commands
     are permitted, not just short-format commands. For example, `quit'
     and `\q' both are recognized. Use `--skip-named-commands' to
     disable named commands. See *Note mysql-commands::.

   *  `--no-auto-rehash', `-A'

     This has the same effect as `-skip-auto-rehash'.  See the
     description for `--auto-rehash'.

   *  `--no-beep', `-b'

     Do not beep when errors occur.

   *  `--no-named-commands', `-g'

     Deprecated, use `--disable-named-commands' instead.
     `--no-named-commands' is removed in MySQL 5.5.

   *  `--no-pager'

     Deprecated form of `--skip-pager'.  See the `--pager' option.
     `--no-pager' is removed in MySQL 5.5.

   *  `--no-tee'

     Deprecated form of `--skip-tee'.  See the `--tee' option.
     `--no-tee' is removed in MySQL 5.5.

   *  `--one-database', `-o'

     Ignore statements except those that occur while the default
     database is the one named on the command line. This option is
     rudimentary and should be used with care. Statement filtering is
     based only on *Note `USE': use. statements.

     Initially, *Note `mysql': mysql. executes statements in the input
     because specifying a database DB_NAME on the command line is
     equivalent to inserting *Note `USE DB_NAME': use. at the beginning
     of the input. Then, for each *Note `USE': use. statement
     encountered, *Note `mysql': mysql. accepts or rejects following
     statements depending on whether the database named is the one on
     the command line. The content of the statements is immaterial.

     Suppose that *Note `mysql': mysql. is invoked to process this set
     of statements:

          DELETE FROM db2.t2;
          USE db2;
          DROP TABLE db1.t1;
          CREATE TABLE db1.t1 (i INT);
          USE db1;
          INSERT INTO t1 (i) VALUES(1);
          CREATE TABLE db2.t1 (j INT);

     If the command line is *Note `mysql --force --one-database db1':
     mysql, *Note `mysql': mysql. handles the input as follows:

        * The *Note `DELETE': delete. statement is executed because the
          default database is `db1', even though the statement names a
          table in a different database.

        * The *Note `DROP TABLE': drop-table. and *Note `CREATE TABLE':
          create-table. statements are not executed because the default
          database is not `db1', even though the statements name a
          table in `db1'.

        * The *Note `INSERT': insert. and *Note `CREATE TABLE':
          create-table. statements are executed because the default
          database is `db1', even though the *Note `CREATE TABLE':
          create-table. statement names a table in a different database.

   *  `--pager[=COMMAND]'

     Use the given command for paging query output. If the command is
     omitted, the default pager is the value of your `PAGER'
     environment variable. Valid pagers are `less', `more', `cat [>
     filename]', and so forth. This option works only on Unix and only
     in interactive mode. To disable paging, use `--skip-pager'.  *Note
     mysql-commands::, discusses output paging further.

   *  `--password[=PASSWORD]', `-p[PASSWORD]'

     The password to use when connecting to the server. If you use the
     short option form (`-p'), you _cannot_ have a space between the
     option and the password. If you omit the PASSWORD value following
     the `--password' or `-p' option on the command line, *Note
     `mysql': mysql. prompts for one.

     Specifying a password on the command line should be considered
     insecure. See *Note password-security-user::. You can use an
     option file to avoid giving the password on the command line.

   *  `--pipe', `-W'

     On Windows, connect to the server using a named pipe. This option
     applies only if the server supports named-pipe connections.

   *  `--port=PORT_NUM', `-P PORT_NUM'

     The TCP/IP port number to use for the connection.

   *  `--prompt=FORMAT_STR'

     Set the prompt to the specified format. The default is `mysql>'.
     The special sequences that the prompt can contain are described in
     *Note mysql-commands::.

   *  `--protocol={TCP|SOCKET|PIPE|MEMORY}'

     The connection protocol to use for connecting to the server.  It
     is useful when the other connection parameters normally would
     cause a protocol to be used other than the one you want. For
     details on the permissible values, see *Note connecting::.

   *  `--quick', `-q'

     Do not cache each query result, print each row as it is received.
     This may slow down the server if the output is suspended. With
     this option, *Note `mysql': mysql. does not use the history file.

   *  `--raw', `-r'

     For tabular output, the `boxing' around columns enables one column
     value to be distinguished from another.  For nontabular output
     (such as is produced in batch mode or when the `--batch' or
     `--silent' option is given), special characters are escaped in the
     output so they can be identified easily. Newline, tab, `NUL', and
     backslash are written as `\n', `\t', `\0', and `\\'. The `--raw'
     option disables this character escaping.

     The following example demonstrates tabular versus nontabular
     output and the use of raw mode to disable escaping:

          % mysql
          mysql> SELECT CHAR(92);
          +----------+
          | CHAR(92) |
          +----------+
          | \        |
          +----------+

          % mysql -s
          mysql> SELECT CHAR(92);
          CHAR(92)
          \\

          % mysql -s -r
          mysql> SELECT CHAR(92);
          CHAR(92)
          \

   *  `--reconnect'

     If the connection to the server is lost, automatically try to
     reconnect. A single reconnect attempt is made each time the
     connection is lost. To suppress reconnection behavior, use
     `--skip-reconnect'.

   *  `--safe-updates', `--i-am-a-dummy', `-U'

     Permit only those *Note `UPDATE': update. and *Note `DELETE':
     delete. statements that specify which rows to modify by using key
     values. If you have set this option in an option file, you can
     override it by using `--safe-updates' on the command line. See
     *Note mysql-tips::, for more information about this option.

   *  `--secure-auth'

     Do not send passwords to the server in old (pre-4.1.1) format.
     This prevents connections except for servers that use the newer
     password format.

   *  `--show-warnings'

     Cause warnings to be shown after each statement if there are any.
     This option applies to interactive and batch mode. This option was
     added in MySQL 5.0.6.

   *  `--sigint-ignore'

     Ignore `SIGINT' signals (typically the result of typing Control+C).

   *  `--silent', `-s'

     Silent mode. Produce less output. This option can be given
     multiple times to produce less and less output.

     This option results in nontabular output format and escaping of
     special characters. Escaping may be disabled by using raw mode;
     see the description for the `--raw' option.

   *  `--skip-column-names', `-N'

     Do not write column names in results.

   *  `--skip-line-numbers', `-L'

     Do not write line numbers for errors. Useful when you want to
     compare result files that include error messages.

   *  `--socket=PATH', `-S PATH'

     For connections to `localhost', the Unix socket file to use, or,
     on Windows, the name of the named pipe to use.

   *  `--ssl*'

     Options that begin with `--ssl' specify whether to connect to the
     server using SSL and indicate where to find SSL keys and
     certificates. See *Note ssl-options::.

   *  `--table', `-t'

     Display output in table format. This is the default for
     interactive use, but can be used to produce table output in batch
     mode.

   *  `--tee=FILE_NAME'

     Append a copy of output to the given file. This option works only
     in interactive mode. *Note mysql-commands::, discusses tee files
     further.

   *  `--unbuffered', `-n'

     Flush the buffer after each query.

   *  `--user=USER_NAME', `-u USER_NAME'

     The MySQL user name to use when connecting to the server.

   *  `--verbose', `-v'

     Verbose mode. Produce more output about what the program does.
     This option can be given multiple times to produce more and more
     output. (For example, `-v -v -v' produces table output format even
     in batch mode.)

   *  `--version', `-V'

     Display version information and exit.

   *  `--vertical', `-E'

     Print query output rows vertically (one line per column value).
     Without this option, you can specify vertical output for
     individual statements by terminating them with `\G'.

   *  `--wait', `-w'

     If the connection cannot be established, wait and retry instead of
     aborting.

   *  `--xml', `-X'

     Produce XML output.

     *Note*:

     Prior to MySQL 5.0.26, there was no differentiation in the output
     when using this option between columns containing the `NULL' value
     and columns containing the string literal `'NULL''; both were
     represented as

          <field name="COLUMN_NAME">NULL</field>

     Beginning with MySQL 5.0.26, the output when `--xml' is used with
     *Note `mysql': mysql. matches that of *Note `mysqldump `--xml'':
     mysqldump. See *Note mysqldump:: for details.

     Beginning with MySQL 5.0.40, the XML output also uses an XML
     namespace, as shown here:

          shell> mysql --xml -uroot -e "SHOW VARIABLES LIKE 'version%'"
          <?xml version="1.0"?>

          <resultset statement="SHOW VARIABLES LIKE 'version%'" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance">
          <row>
          <field name="Variable_name">version</field>
          <field name="Value">5.0.40-debug</field>
          </row>

          <row>
          <field name="Variable_name">version_comment</field>
          <field name="Value">Source distribution</field>
          </row>

          <row>
          <field name="Variable_name">version_compile_machine</field>
          <field name="Value">i686</field>
          </row>

          <row>
          <field name="Variable_name">version_compile_os</field>
          <field name="Value">suse-linux-gnu</field>
          </row>
          </resultset>

     (See Bug #25946.)

You can also set the following variables by using `--VAR_NAME=VALUE'.
The `--set-variable' format is deprecated.

   *  `connect_timeout'

     The number of seconds before connection timeout. (Default value is
     `0'.)

   *  `max_allowed_packet'

     The maximum packet length to send to or receive from the server.
     (Default value is 16MB.)

   *  `max_join_size'

     The automatic limit for rows in a join when using
     `--safe-updates'. (Default value is 1,000,000.)

   * `net_buffer_length'

     The buffer size for TCP/IP and socket communication.  (Default
     value is 16KB.)

   *  `select_limit'

     The automatic limit for *Note `SELECT': select. statements when
     using `--safe-updates'. (Default value is 1,000.)

It is also possible to set variables by using `--VAR_NAME=VALUE'.  The
`--set-variable' format is deprecated.


File: manual.info,  Node: mysql-commands,  Next: mysql-history-file,  Prev: mysql-command-options,  Up: mysql

5.5.1.2 `mysql' Commands
........................

*Note `mysql': mysql. sends each SQL statement that you issue to the
server to be executed. There is also a set of commands that *Note
`mysql': mysql. itself interprets. For a list of these commands, type
`help' or `\h' at the `mysql>' prompt:

     mysql> help

     List of all MySQL commands:
     Note that all text commands must be first on line and end with ';'
     ?         (\?) Synonym for `help'.
     clear     (\c) Clear command.
     connect   (\r) Reconnect to the server. Optional arguments are db and host.
     delimiter (\d) Set statement delimiter.
     edit      (\e) Edit command with $EDITOR.
     ego       (\G) Send command to mysql server, display result vertically.
     exit      (\q) Exit mysql. Same as quit.
     go        (\g) Send command to mysql server.
     help      (\h) Display this help.
     nopager   (\n) Disable pager, print to stdout.
     notee     (\t) Don't write into outfile.
     pager     (\P) Set PAGER [to_pager]. Print the query results via PAGER.
     print     (\p) Print current command.
     prompt    (\R) Change your mysql prompt.
     quit      (\q) Quit mysql.
     rehash    (\#) Rebuild completion hash.
     source    (\.) Execute an SQL script file. Takes a file name as an argument.
     status    (\s) Get status information from the server.
     system    (\!) Execute a system shell command.
     tee       (\T) Set outfile [to_outfile]. Append everything into given
                    outfile.
     use       (\u) Use another database. Takes database name as argument.
     charset   (\C) Switch to another charset. Might be needed for processing
                    binlog with multi-byte charsets.
     warnings  (\W) Show warnings after every statement.
     nowarning (\w) Don't show warnings after every statement.

     For server side help, type 'help contents'

Each command has both a long and short form. The long form is not case
sensitive; the short form is. The long form can be followed by an
optional semicolon terminator, but the short form should not.

The use of short-form commands within multi-line `/* ...  */' comments
is not supported.

   * `help [ARG]', `\h [ARG]', `\? [ARG]', `? [ARG]'

     Display a help message listing the available *Note `mysql': mysql.
     commands.

     If you provide an argument to the `help' command, *Note `mysql':
     mysql. uses it as a search string to access server-side help from
     the contents of the MySQL Reference Manual. For more information,
     see *Note mysql-server-side-help::.

   * `charset CHARSET_NAME', `\C CHARSET_NAME'

     Change the default character set and issue a `SET NAMES'
     statement. This enables the character set to remain synchronized
     on the client and server if *Note `mysql': mysql. is run with
     auto-reconnect enabled (which is not recommended), because the
     specified character set is used for reconnects. This command was
     added in MySQL 5.0.19.

   * `clear', `\c'

     Clear the current input. Use this if you change your mind about
     executing the statement that you are entering.

   * `connect [DB_NAME HOST_NAME]]', `\r [DB_NAME HOST_NAME]]'

     Reconnect to the server. The optional database name and host name
     arguments may be given to specify the default database or the host
     where the server is running. If omitted, the current values are
     used.

   * `delimiter STR', `\d STR'

     Change the string that *Note `mysql': mysql. interprets as the
     separator between SQL statements. The default is the semicolon
     character (``;'').

     The delimiter string can be specified as an unquoted or quoted
     argument on the `delimiter' command line. Quoting can be done with
     either single quote (`''), douple quote (`"'), or backtick (``')
     characters. To include a quote within a quoted string, either
     quote the string with a different quote character or escape the
     quote with a backslash (``\'') character.  Backslash should be
     avoided outside of quoted strings because it is the escape
     character for MySQL. For an unquoted argument, the delimiter is
     read up to the first space or end of line. For a quoted argument,
     the delimiter is read up to the matching quote on the line.

     *Note `mysql': mysql. interprets instances of the delimiter string
     as a statement delimiter anywhere it occurs, except within quoted
     strings. Be careful about defining a delimiter that might occur
     within other words.  For example, if you define the delimiter as
     `X', you will be unable to use the word `INDEX' in statements.
     *Note `mysql': mysql. interprets this as `INDE' followed by the
     delimiter `X'.

     When the delimiter recognized by *Note `mysql': mysql. is set to
     something other than the default of ``;'', instances of that
     character are sent to the server without interpretation.  However,
     the server itself still interprets ``;'' as a statement delimiter
     and processes statements accordingly. This behavior on the server
     side comes into play for multiple-statement execution (see *Note
     c-api-multiple-queries::), and for parsing the body of stored
     procedures and functions and triggers (see *Note
     stored-programs-defining::).

   * `edit', `\e'

     Edit the current input statement. *Note `mysql': mysql.  checks
     the values of the `EDITOR' and `VISUAL' environment variables to
     determine which editor to use. The default editor is `vi' if
     neither variable is set.

     The `edit' command works only in Unix.

   * `ego', `\G'

     Send the current statement to the server to be executed and
     display the result using vertical format.

     Be careful about defining a delimiter that might occur within
     other words. For example, if you define the delimiter as `X', you
     will be unable to use the word `INDEX' in statements.

   * `exit', `\q'

     Exit *Note `mysql': mysql.

   * `go', `\g'

     Send the current statement to the server to be executed.

   * `nopager', `\n'

     Disable output paging. See the description for `pager'.

     The `nopager' command works only in Unix.

   * `notee', `\t'

     Disable output copying to the tee file. See the description for
     `tee'.

   * `nowarning', `\w'

     Enable display of warnings after each statement. This command was
     added in MySQL 5.0.6.

   * `pager [COMMAND]', `\P [COMMAND]'

     Enable output paging. By using the `--pager' option when you invoke
     *Note `mysql': mysql, it is possible to browse or search query
     results in interactive mode with Unix programs such as `less',
     `more', or any other similar program. If you specify no value for
     the option, *Note `mysql': mysql. checks the value of the `PAGER'
     environment variable and sets the pager to that. Pager
     functionality works only in interactive mode.

     Output paging can be enabled interactively with the `pager'
     command and disabled with `nopager'. The command takes an optional
     argument; if given, the paging program is set to that. With no
     argument, the pager is set to the pager that was set on the
     command line, or `stdout' if no pager was specified.

     Output paging works only in Unix because it uses the `popen()'
     function, which does not exist on Windows. For Windows, the `tee'
     option can be used instead to save query output, although it is
     not as convenient as `pager' for browsing output in some
     situations.

   * `print', `\p'

     Print the current input statement without executing it.

   * `prompt [STR]', `\R [STR]'

     Reconfigure the *Note `mysql': mysql. prompt to the given string.
     The special character sequences that can be used in the prompt are
     described later in this section.

     If you specify the `prompt' command with no argument, *Note
     `mysql': mysql. resets the prompt to the default of `mysql>'.

   * `quit', `\q'

     Exit *Note `mysql': mysql.

   * `rehash', `\#'

     Rebuild the completion hash that enables database, table, and
     column name completion while you are entering statements. (See the
     description for the `--auto-rehash' option.)

   * `source FILE_NAME', `\.  FILE_NAME'

     Read the named file and executes the statements contained therein.
     On Windows, you can specify path name separators as `/' or `\\'.

   * `status', `\s'

     Provide status information about the connection and the server you
     are using. If you are running in `--safe-updates' mode, `status'
     also prints the values for the *Note `mysql': mysql. variables
     that affect your queries.

   * `system COMMAND', `\!  COMMAND'

     Execute the given command using your default command interpreter.

     The `system' command works only in Unix.

   * `tee [FILE_NAME]', `\T [FILE_NAME]'

     By using the `--tee' option when you invoke *Note `mysql': mysql,
     you can log statements and their output. All the data displayed on
     the screen is appended into a given file. This can be very useful
     for debugging purposes also. *Note `mysql': mysql. flushes results
     to the file after each statement, just before it prints its next
     prompt. Tee functionality works only in interactive mode.

     You can enable this feature interactively with the `tee' command.
     Without a parameter, the previous file is used. The `tee' file can
     be disabled with the `notee' command.  Executing `tee' again
     re-enables logging.

   * `use DB_NAME', `\u DB_NAME'

     Use DB_NAME as the default database.

   * `warnings', `\W'

     Enable display of warnings after each statement (if there are
     any). This command was added in MySQL 5.0.6.

Here are a few tips about the `pager' command:

   * You can use it to write to a file and the results go only to the
     file:

          mysql> pager cat > /tmp/log.txt

     You can also pass any options for the program that you want to use
     as your pager:

          mysql> pager less -n -i -S

   * In the preceding example, note the `-S' option. You may find it
     very useful for browsing wide query results. Sometimes a very wide
     result set is difficult to read on the screen. The `-S' option to
     `less' can make the result set much more readable because you can
     scroll it horizontally using the left-arrow and right-arrow keys.
     You can also use `-S' interactively within `less' to switch the
     horizontal-browse mode on and off. For more information, read the
     `less' manual page:

          shell> man less

   * The `-F' and `-X' options may be used with `less' to cause it to
     exit if output fits on one screen, which is convenient when no
     scrolling is necessary:

          mysql> pager less -n -i -S -F -X

   * You can specify very complex pager commands for handling query
     output:

          mysql> pager cat | tee /dr1/tmp/res.txt \
                    | tee /dr2/tmp/res2.txt | less -n -i -S

     In this example, the command would send query results to two files
     in two different directories on two different file systems mounted
     on `/dr1' and `/dr2', yet still display the results onscreen using
     `less'.

You can also combine the `tee' and `pager' functions. Have a `tee' file
enabled and `pager' set to `less', and you are able to browse the
results using the `less' program and still have everything appended
into a file the same time. The difference between the Unix `tee' used
with the `pager' command and the *Note `mysql': mysql. built-in `tee'
command is that the built-in `tee' works even if you do not have the
Unix `tee' available. The built-in `tee' also logs everything that is
printed on the screen, whereas the Unix `tee' used with `pager' does
not log quite that much.  Additionally, `tee' file logging can be turned
on and off interactively from within *Note `mysql': mysql.  This is
useful when you want to log some queries to a file, but not others.

The `prompt' command reconfigures the default `mysql>' prompt. The
string for defining the prompt can contain the following special
sequences.

Option      Description
`\c'        A counter that increments for each statement you issue
`\D'        The full current date
`\d'        The default database
`\h'        The server host
`\l'        The current delimiter (new in 5.0.25)
`\m'        Minutes of the current time
`\n'        A newline character
`\O'        The current month in three-letter format (Jan, Feb,
            ...)
`\o'        The current month in numeric format
`\P'        am/pm
`\p'        The current TCP/IP port or socket file
`\R'        The current time, in 24-hour military time (0-23)
`\r'        The current time, standard 12-hour time (1-12)
`\S'        Semicolon
`\s'        Seconds of the current time
`\t'        A tab character
`\U'        Your full `USER_NAME@HOST_NAME' account name
`\u'        Your user name
`\v'        The server version
`\w'        The current day of the week in three-letter format
            (Mon, Tue, ...)
`\Y'        The current year, four digits
`\y'        The current year, two digits
`\_'        A space
`\ '        A space (a space follows the backslash)
`\''        Single quote
`\"'        Double quote
`\\'        A literal ``\'' backslash character
`\X'        X, for any `X' not listed above

You can set the prompt in several ways:

   * _Use an environment variable._ You can set the `MYSQL_PS1'
     environment variable to a prompt string. For example:

          shell> export MYSQL_PS1="(\u@\h) [\d]> "

   * _Use a command-line option._ You can set the `--prompt' option on
     the command line to *Note `mysql': mysql. For example:

          shell> mysql --prompt="(\u@\h) [\d]> "
          (user@host) [database]>

   * _Use an option file._ You can set the `prompt' option in the
     `[mysql]' group of any MySQL option file, such as `/etc/my.cnf' or
     the `.my.cnf' file in your home directory.  For example:

          [mysql]
          prompt=(\\u@\\h) [\\d]>\\_

     In this example, note that the backslashes are doubled. If you set
     the prompt using the `prompt' option in an option file, it is
     advisable to double the backslashes when using the special prompt
     options. There is some overlap in the set of permissible prompt
     options and the set of special escape sequences that are
     recognized in option files. (The rules for escape sequences in
     option files are listed in *Note option-files::.) The overlap may
     cause you problems if you use single backslashes. For example,
     `\s' is interpreted as a space rather than as the current seconds
     value. The following example shows how to define a prompt within
     an option file to include the current time in `HH:MM:SS>' format:

          [mysql]
          prompt="\\r:\\m:\\s> "

   * _Set the prompt interactively._ You can change your prompt
     interactively by using the `prompt' (or `\R') command. For example:

          mysql> prompt (\u@\h) [\d]>\_
          PROMPT set to '(\u@\h) [\d]>\_'
          (USER@HOST) [DATABASE]>
          (USER@HOST) [DATABASE]> prompt
          Returning to default PROMPT of mysql>
          mysql>


File: manual.info,  Node: mysql-history-file,  Next: mysql-server-side-help,  Prev: mysql-commands,  Up: mysql

5.5.1.3 `mysql' History File
............................

On Unix, the *Note `mysql': mysql. client writes a record of executed
statements to a history file. By default, this file is named
`.mysql_history' and is created in your home directory. To specify a
different file, set the value of the `MYSQL_HISTFILE' environment
variable.

The `.mysql_history' should be protected with a restrictive access mode
because sensitive information might be written to it, such as the text
of SQL statements that contain passwords. See *Note
password-security-user::.

It is possible to suppress logging of statements to the history file by
using the `--batch' or `--execute' option.

If you do not want to maintain a history file, first remove
`.mysql_history' if it exists, and then use either of the following
techniques:

   * Set the `MYSQL_HISTFILE' variable to `/dev/null'. To cause this
     setting to take effect each time you log in, put the setting in
     one of your shell's startup files.

   * Create `.mysql_history' as a symbolic link to `/dev/null':

          shell> ln -s /dev/null $HOME/.mysql_history

     You need do this only once.


File: manual.info,  Node: mysql-server-side-help,  Next: batch-commands,  Prev: mysql-history-file,  Up: mysql

5.5.1.4 `mysql' Server-Side Help
................................

     mysql> help SEARCH_STRING

If you provide an argument to the `help' command, *Note `mysql': mysql.
uses it as a search string to access server-side help from the contents
of the MySQL Reference Manual. The proper operation of this command
requires that the help tables in the `mysql' database be initialized
with help topic information (see *Note server-side-help-support::).

If there is no match for the search string, the search fails:

     mysql> help me

     Nothing found
     Please try to run 'help contents' for a list of all accessible topics

Use *Note `help contents': help. to see a list of the help categories:

     mysql> help contents
     You asked for help about help category: "Contents"
     For more information, type 'help <item>', where <item> is one of the
     following categories:
        Account Management
        Administration
        Data Definition
        Data Manipulation
        Data Types
        Functions
        Functions and Modifiers for Use with GROUP BY
        Geographic Features
        Language Structure
        Storage Engines
        Stored Routines
        Table Maintenance
        Transactions
        Triggers

If the search string matches multiple items, *Note `mysql': mysql.
shows a list of matching topics:

     mysql> help logs
     Many help items for your request exist.
     To make a more specific request, please type 'help <item>',
     where <item> is one of the following topics:
        SHOW
        SHOW BINARY LOGS
        SHOW ENGINE
        SHOW LOGS

Use a topic as the search string to see the help entry for that topic:

     mysql> help show binary logs
     Name: 'SHOW BINARY LOGS'
     Description:
     Syntax:
     SHOW BINARY LOGS
     SHOW MASTER LOGS

     Lists the binary log files on the server. This statement is used as
     part of the procedure described in [purge-binary-logs], that shows how
     to determine which logs can be purged.

     mysql> SHOW BINARY LOGS;
     +---------------+-----------+
     | Log_name      | File_size |
     +---------------+-----------+
     | binlog.000015 |    724935 |
     | binlog.000016 |    733481 |
     +---------------+-----------+


File: manual.info,  Node: batch-commands,  Next: mysql-tips,  Prev: mysql-server-side-help,  Up: mysql

5.5.1.5 Executing SQL Statements from a Text File
.................................................

The *Note `mysql': mysql. client typically is used interactively, like
this:

     shell> mysql DB_NAME

However, it is also possible to put your SQL statements in a file and
then tell *Note `mysql': mysql. to read its input from that file. To do
so, create a text file TEXT_FILE that contains the statements you wish
to execute. Then invoke *Note `mysql': mysql. as shown here:

     shell> mysql DB_NAME < TEXT_FILE

If you place a `USE DB_NAME' statement as the first statement in the
file, it is unnecessary to specify the database name on the command
line:

     shell> mysql < text_file

If you are already running *Note `mysql': mysql, you can execute an SQL
script file using the `source' command or `\.' command:

     mysql> source FILE_NAME
     mysql> \. FILE_NAME

Sometimes you may want your script to display progress information to
the user. For this you can insert statements like this:

     SELECT '<info_to_display>' AS ' ';

The statement shown outputs `<info_to_display>'.

You can also invoke *Note `mysql': mysql. with the `--verbose' option,
which causes each statement to be displayed before the result that it
produces.

As of MySQL 5.0.54, *Note `mysql': mysql. ignores Unicode byte order
mark (BOM) characters at the beginning of input files. Previously, it
read them and sent them to the server, resulting in a syntax error.
Presence of a BOM does not cause *Note `mysql': mysql. to change its
default character set. To do that, invoke *Note `mysql': mysql. with an
option such as `--default-character-set=utf8'.

For more information about batch mode, see *Note batch-mode::.


File: manual.info,  Node: mysql-tips,  Prev: batch-commands,  Up: mysql

5.5.1.6 `mysql' Tips
....................

* Menu:

* vertical-query-results::       Displaying Query Results Vertically
* safe-updates::                 Using the `--safe-updates' Option
* mysql-reconnect::              Disabling `mysql' Auto-Reconnect

This section describes some techniques that can help you use *Note
`mysql': mysql. more effectively.


File: manual.info,  Node: vertical-query-results,  Next: safe-updates,  Prev: mysql-tips,  Up: mysql-tips

5.5.1.7 Displaying Query Results Vertically
...........................................

Some query results are much more readable when displayed vertically,
instead of in the usual horizontal table format.  Queries can be
displayed vertically by terminating the query with \G instead of a
semicolon. For example, longer text values that include newlines often
are much easier to read with vertical output:

     mysql> SELECT * FROM mails WHERE LENGTH(txt) < 300 LIMIT 300,1\G
     *************************** 1. row ***************************
       msg_nro: 3068
          date: 2000-03-01 23:29:50
     time_zone: +0200
     mail_from: Monty
         reply: monty@no.spam.com
       mail_to: "Thimble Smith" <tim@no.spam.com>
           sbj: UTF-8
           txt: >>>>> "Thimble" == Thimble Smith writes:

     Thimble> Hi.  I think this is a good idea.  Is anyone familiar
     Thimble> with UTF-8 or Unicode? Otherwise, I'll put this on my
     Thimble> TODO list and see what happens.

     Yes, please do that.

     Regards,
     Monty
          file: inbox-jani-1
          hash: 190402944
     1 row in set (0.09 sec)


File: manual.info,  Node: safe-updates,  Next: mysql-reconnect,  Prev: vertical-query-results,  Up: mysql-tips

5.5.1.8 Using the `--safe-updates' Option
.........................................

For beginners, a useful startup option is `--safe-updates' (or
`--i-am-a-dummy', which has the same effect). It is helpful for cases
when you might have issued a `DELETE FROM TBL_NAME' statement but
forgotten the `WHERE' clause. Normally, such a statement deletes all
rows from the table. With `--safe-updates', you can delete rows only by
specifying the key values that identify them.  This helps prevent
accidents.

When you use the `--safe-updates' option, *Note `mysql': mysql. issues
the following statement when it connects to the MySQL server:

     SET sql_safe_updates=1, sql_select_limit=1000, sql_max_join_size=1000000;

See *Note server-system-variables::.

The *Note `SET': set-option.  statement has the following effects:

   * You are not permitted to execute an *Note `UPDATE': update. or
     *Note `DELETE': delete. statement unless you specify a key
     constraint in the `WHERE' clause or provide a `LIMIT' clause (or
     both). For example:

          UPDATE TBL_NAME SET NOT_KEY_COLUMN=VAL WHERE KEY_COLUMN=VAL;

          UPDATE TBL_NAME SET NOT_KEY_COLUMN=VAL LIMIT 1;

   * The server limits all large *Note `SELECT': select. results to
     1,000 rows unless the statement includes a `LIMIT' clause.

   * The server aborts multiple-table *Note `SELECT': select.
     statements that probably need to examine more than 1,000,000 row
     combinations.

To specify limits different from 1,000 and 1,000,000, you can override
the defaults by using the `--select_limit' and `--max_join_size'
options:

     shell> mysql --safe-updates --select_limit=500 --max_join_size=10000


File: manual.info,  Node: mysql-reconnect,  Prev: safe-updates,  Up: mysql-tips

5.5.1.9 Disabling `mysql' Auto-Reconnect
........................................

If the *Note `mysql': mysql. client loses its connection to the server
while sending a statement, it immediately and automatically tries to
reconnect once to the server and send the statement again. However,
even if *Note `mysql': mysql.  succeeds in reconnecting, your first
connection has ended and all your previous session objects and settings
are lost: temporary tables, the autocommit mode, and user-defined and
session variables. Also, any current transaction rolls back.  This
behavior may be dangerous for you, as in the following example where
the server was shut down and restarted between the first and second
statements without you knowing it:

     mysql> SET @a=1;
     Query OK, 0 rows affected (0.05 sec)

     mysql> INSERT INTO t VALUES(@a);
     ERROR 2006: MySQL server has gone away
     No connection. Trying to reconnect...
     Connection id:    1
     Current database: test

     Query OK, 1 row affected (1.30 sec)

     mysql> SELECT * FROM t;
     +------+
     | a    |
     +------+
     | NULL |
     +------+
     1 row in set (0.05 sec)

The `@a' user variable has been lost with the connection, and after the
reconnection it is undefined. If it is important to have *Note `mysql':
mysql. terminate with an error if the connection has been lost, you can
start the *Note `mysql': mysql. client with the `--skip-reconnect'
option.

For more information about auto-reconnect and its effect on state
information when a reconnection occurs, see *Note auto-reconnect::.


File: manual.info,  Node: mysqladmin,  Next: mysqlcheck,  Prev: mysql,  Up: programs-client

5.5.2 `mysqladmin' -- Client for Administering a MySQL Server
-------------------------------------------------------------

*Note `mysqladmin': mysqladmin. is a client for performing
administrative operations. You can use it to check the server's
configuration and current status, to create and drop databases, and
more.

Invoke *Note `mysqladmin': mysqladmin. like this:

     shell> mysqladmin [OPTIONS] COMMAND [COMMAND-ARG] [COMMAND [COMMAND-ARG]] ...

*Note `mysqladmin': mysqladmin. supports the following commands.  Some
of the commands take an argument following the command name.

   *  `create DB_NAME'

     Create a new database named DB_NAME.

   *  `debug'

     Tell the server to write debug information to the error log.

   *  `drop DB_NAME'

     Delete the database named DB_NAME and all its tables.

   *  `extended-status'

     Display the server status variables and their values.

   *  `flush-hosts'

     Flush all information in the host cache.

   *  `flush-logs'

     Flush all logs.

   *  `flush-privileges'

     Reload the grant tables (same as `reload').

   *  `flush-status'

     Clear status variables.

   *  `flush-tables'

     Flush all tables.

   *  `flush-threads'

     Flush the thread cache.

   *  `kill ID,ID,...'

     Kill server threads. If multiple thread ID values are given, there
     must be no spaces in the list.

   *  `old-password NEW-PASSWORD'

     This is like the `password' command but stores the password using
     the old (pre-4.1) password-hashing format. (See *Note
     password-hashing::.)

   *  `password NEW-PASSWORD'

     Set a new password. This changes the password to NEW-PASSWORD for
     the account that you use with *Note `mysqladmin': mysqladmin. for
     connecting to the server. Thus, the next time you invoke *Note
     `mysqladmin': mysqladmin. (or any other client program) using the
     same account, you will need to specify the new password.

     If the NEW-PASSWORD value contains spaces or other characters that
     are special to your command interpreter, you need to enclose it
     within quotation marks. On Windows, be sure to use double
     quotation marks rather than single quotation marks; single
     quotation marks are not stripped from the password, but rather are
     interpreted as part of the password. For example:

          shell> mysqladmin password "my new password"

     *Caution*:

     Do not use this command used if the server was started with the
     `--skip-grant-tables' option.  No password change will be applied.
     This is true even if you precede the `password' command with
     `flush-privileges' on the same command line to re-enable the grant
     tables because the flush operation occurs after you connect.
     However, you can use *Note `mysqladmin flush-privileges':
     mysqladmin. to re-enable the grant table and then use a separate
     *Note `mysqladmin password': mysqladmin. command to change the
     password.

   *  `ping'

     Check whether the server is available. The return status from
     *Note `mysqladmin': mysqladmin. is 0 if the server is running, 1
     if it is not. This is 0 even in case of an error such as `Access
     denied', because this means that the server is running but refused
     the connection, which is different from the server not running.

   *  `processlist'

     Show a list of active server threads. This is like the output of
     the *Note `SHOW PROCESSLIST': show-processlist. statement. If the
     `--verbose' option is given, the output is like that of *Note
     `SHOW FULL PROCESSLIST': show-processlist. (See *Note
     show-processlist::.)

   *  `reload'

     Reload the grant tables.

   *  `refresh'

     Flush all tables and close and open log files.

   *  `shutdown'

     Stop the server.

   *  `start-slave'

     Start replication on a slave server.

   *  `status'

     Display a short server status message.

   *  `stop-slave'

     Stop replication on a slave server.

   *  `variables'

     Display the server system variables and their values.

   *  `version'

     Display version information from the server.

All commands can be shortened to any unique prefix. For example:

     shell> mysqladmin proc stat
     +----+-------+-----------+----+---------+------+-------+------------------+
     | Id | User  | Host      | db | Command | Time | State | Info             |
     +----+-------+-----------+----+---------+------+-------+------------------+
     | 51 | monty | localhost |    | Query   | 0    |       | show processlist |
     +----+-------+-----------+----+---------+------+-------+------------------+
     Uptime: 1473624  Threads: 1  Questions: 39487
     Slow queries: 0  Opens: 541  Flush tables: 1
     Open tables: 19  Queries per second avg: 0.0268

The *Note `mysqladmin status': mysqladmin. command result displays the
following values:

   * `Uptime'

     The number of seconds the MySQL server has been running.

   * `Threads'

     The number of active threads (clients).

   * `Questions'

     The number of questions (queries) from clients since the server
     was started.

   * `Slow queries'

     The number of queries that have taken more than `long_query_time'
     seconds.  See *Note slow-query-log::.

   * `Opens'

     The number of tables the server has opened.

   * `Flush tables'

     The number of `flush-*', `refresh', and `reload' commands the
     server has executed.

   * `Open tables'

     The number of tables that currently are open.

   * `Memory in use'

     The amount of memory allocated directly by *Note `mysqld': mysqld.
     This value is displayed only when MySQL has been compiled with
     `--with-debug=full'.

   * `Maximum memory used'

     The maximum amount of memory allocated directly by *Note `mysqld':
     mysqld. This value is displayed only when MySQL has been compiled
     with `--with-debug=full'.

If you execute *Note `mysqladmin shutdown': mysqladmin. when connecting
to a local server using a Unix socket file, *Note `mysqladmin':
mysqladmin. waits until the server's process ID file has been removed,
to ensure that the server has stopped properly.

*Note `mysqladmin': mysqladmin. supports the following options, which
can be specified on the command line or in the `[mysqladmin]' and
`[client]' groups of an option file. *Note `mysqladmin': mysqladmin.
also supports the options for processing option files described at
*Note option-file-options::.

*`mysqladmin' Options*

Format      Option File Description                   IntroductionDeprecatedRemoved
-compress   compress    Compress all information                      
                        sent between the client and                   
                        the server                                    
-connect_timeout=secondsconnect_timeoutThe number of seconds before                  
                        connection timeout                            
-count=#    count       The number of iterations to                   
                        make for repeated command                     
                        execution                                     
-debug[=debug_options]debug       Write a debugging log                         
-default-character-set=charset_namedefault-character-setUse charset_name as the                       
                        default character set                         
-force      force       Continue even if an SQL                       
                        error occurs                                  
-help                   Display help message and exit                 
-host=host_namehost        Connect to the MySQL server                   
                        on the given host                             
-password[=password]password    The password to use when                      
                        connecting to the server                      
-pipe                   On Windows, connect to                        
                        server using a named pipe                     
-port=port_numport        The TCP/IP port number to                     
                        use for the connection                        
-protocol=typeprotocol    The connection protocol to                    
                        use                                           
-relative   relative    Show the difference between                   
                        the current and previous                      
                        values when  used with the                    
                        -sleep option                                 
-shutdown_timeout=secondsshutdown_timeoutThe maximum number of                         
                        seconds to wait for server                    
                        shutdown                                      
-silent     silent      Silent mode                                   
-sleep=delaysleep       Execute commands repeatedly,                  
                        sleeping for delay seconds                    
                        in between                                    
-socket=pathsocket      For connections to localhost                  
-ssl-ca=file_namessl-ca      The path to a file that                       
                        contains a list of trusted                    
                        SSL CAs                                       
-ssl-capath=dir_namessl-capath  The path to a directory that                  
                        contains trusted SSL CA                       
                        certificates  in PEM format                   
-ssl-cert=file_namessl-cert    The name of the SSL                           
                        certificate file to use for                   
                        establishing a  secure                        
                        connection                                    
-ssl-cipher=cipher_listssl-cipher  A list of allowable ciphers                   
                        to use for SSL encryption                     
-ssl-key=file_namessl-key     The name of the SSL key file                  
                        to use for establishing a                     
                        secure  connection                            
-ssl-verify-server-certssl-verify-server-certThe server's Common Name                      
                        value in its certificate is                   
                        verified  against the host                    
                        name used when connecting to                  
                        the server                                    
-user=user_name,user        The MySQL user name to use                    
                        when connecting to the server                 
-verbose                Verbose mode                                  
-version                Display version information                   
                        and exit                                      
-vertical   vertical    Print query output rows                       
                        vertically (one line per                      
                        column value)                                 
-wait       wait        If the connection cannot be                   
                        established, wait and retry                   
                        instead of  aborting                          

   *  `--help', `-?'

     Display a help message and exit.

   *  `--character-sets-dir=PATH'

     The directory where character sets are installed. See *Note
     charset-configuration::.

   *  `--compress', `-C'

     Compress all information sent between the client and the server if
     both support compression.

   *  `--count=N', `-c N'

     The number of iterations to make for repeated command execution if
     the `--sleep' option is given.

   *  `--debug[=DEBUG_OPTIONS]', `-# [DEBUG_OPTIONS]'

     Write a debugging log. A typical DEBUG_OPTIONS string is
     `'d:t:o,FILE_NAME''.  The default is
     `'d:t:o,/tmp/mysqladmin.trace''.

   *  `--default-character-set=CHARSET_NAME'

     Use CHARSET_NAME as the default character set. See *Note
     charset-configuration::.

   *  `--force', `-f'

     Do not ask for confirmation for the `drop DB_NAME' command. With
     multiple commands, continue even if an error occurs.

   *  `--host=HOST_NAME', `-h HOST_NAME'

     Connect to the MySQL server on the given host.

   *  `--password[=PASSWORD]', `-p[PASSWORD]'

     The password to use when connecting to the server. If you use the
     short option form (`-p'), you _cannot_ have a space between the
     option and the password. If you omit the PASSWORD value following
     the `--password' or `-p' option on the command line, *Note
     `mysqladmin': mysqladmin. prompts for one.

     Specifying a password on the command line should be considered
     insecure. See *Note password-security-user::. You can use an
     option file to avoid giving the password on the command line.

   *  `--pipe', `-W'

     On Windows, connect to the server using a named pipe. This option
     applies only if the server supports named-pipe connections.

   *  `--port=PORT_NUM', `-P PORT_NUM'

     The TCP/IP port number to use for the connection.

   *  `--protocol={TCP|SOCKET|PIPE|MEMORY}'

     The connection protocol to use for connecting to the server.  It
     is useful when the other connection parameters normally would
     cause a protocol to be used other than the one you want. For
     details on the permissible values, see *Note connecting::.

   *  `--relative', `-r'

     Show the difference between the current and previous values when
     used with the `--sleep' option. This option works only with the
     `extended-status' command.

   *  `--silent', `-s'

     Exit silently if a connection to the server cannot be established.

   *  `--sleep=DELAY', `-i DELAY'

     Execute commands repeatedly, sleeping for DELAY seconds in
     between. The `--count' option determines the number of iterations.
     If `--count' is not given, *Note `mysqladmin': mysqladmin.
     executes commands indefinitely until interrupted.

   *  `--socket=PATH', `-S PATH'

     For connections to `localhost', the Unix socket file to use, or,
     on Windows, the name of the named pipe to use.

   *  `--ssl*'

     Options that begin with `--ssl' specify whether to connect to the
     server using SSL and indicate where to find SSL keys and
     certificates. See *Note ssl-options::.

   *  `--user=USER_NAME', `-u USER_NAME'

     The MySQL user name to use when connecting to the server.

   *  `--verbose', `-v'

     Verbose mode. Print more information about what the program does.

   *  `--version', `-V'

     Display version information and exit.

   *  `--vertical', `-E'

     Print output vertically. This is similar to `--relative', but
     prints output vertically.

   *  `--wait[=COUNT]', `-w[COUNT]'

     If the connection cannot be established, wait and retry instead of
     aborting. If a COUNT value is given, it indicates the number of
     times to retry.  The default is one time.

You can also set the following variables by using `--VAR_NAME=VALUE'
The `--set-variable' format is deprecated.  syntax:

   *  `connect_timeout'

     The maximum number of seconds before connection timeout. The
     default value is 43200 (12 hours).

   *  `shutdown_timeout'

     The maximum number of seconds to wait for server shutdown.  The
     default value is 3600 (1 hour).

It is also possible to set variables by using `--VAR_NAME=VALUE'.  The
`--set-variable' format is deprecated.


File: manual.info,  Node: mysqlcheck,  Next: mysqldump,  Prev: mysqladmin,  Up: programs-client

5.5.3 `mysqlcheck' -- A Table Maintenance Program
-------------------------------------------------

The *Note `mysqlcheck': mysqlcheck. client performs table maintenance:
It checks, repairs, optimizes, or analyzes tables.

Each table is locked and therefore unavailable to other sessions while
it is being processed, although for check operations, the table is
locked with a `READ' lock only (see *Note lock-tables::, for more
information about `READ' and `WRITE' locks).  Table maintenance
operations can be time-consuming, particularly for large tables. If you
use the `--databases' or `--all-databases' option to process all tables
in one or more databases, an invocation of *Note `mysqlcheck':
mysqlcheck. might take a long time. (This is also true for *Note
`mysql_upgrade': mysql-upgrade. because that program invokes *Note
`mysqlcheck': mysqlcheck. to check all tables and repair them if
necessary.)

*Note `mysqlcheck': mysqlcheck. is similar in function to *Note
`myisamchk': myisamchk, but works differently. The main operational
difference is that *Note `mysqlcheck': mysqlcheck.  must be used when
the *Note `mysqld': mysqld. server is running, whereas *Note
`myisamchk': myisamchk. should be used when it is not. The benefit of
using *Note `mysqlcheck': mysqlcheck. is that you do not have to stop
the server to perform table maintenance.

*Note `mysqlcheck': mysqlcheck. uses the SQL statements *Note `CHECK
TABLE': check-table, *Note `REPAIR TABLE': repair-table, *Note `ANALYZE
TABLE': analyze-table, and *Note `OPTIMIZE TABLE': optimize-table. in a
convenient way for the user. It determines which statements to use for
the operation you want to perform, and then sends the statements to the
server to be executed. For details about which storage engines each
statement works with, see the descriptions for those statements in
*Note table-maintenance-sql::.

The `MyISAM' storage engine supports all four maintenance operations,
so *Note `mysqlcheck': mysqlcheck. can be used to perform any of them
on `MyISAM' tables.  Other storage engines do not necessarily support
all operations.  In such cases, an error message is displayed. For
example, if `test.t' is a `MEMORY' table, an attempt to check it
produces this result:

     shell> mysqlcheck test t
     test.t
     note     : The storage engine for the table doesn't support check

If *Note `mysqlcheck': mysqlcheck. is unable to repair a table, see
*Note rebuilding-tables:: for manual table repair strategies. This will
be the case, for example, for `InnoDB' tables, which can be checked with
*Note `CHECK TABLE': check-table, but not repaired with *Note `REPAIR
TABLE': repair-table.

*Caution*:

It is best to make a backup of a table before performing a table repair
operation; under some circumstances the operation might cause data
loss. Possible causes include but are not limited to file system errors.

There are three general ways to invoke *Note `mysqlcheck': mysqlcheck.:

     shell> mysqlcheck [OPTIONS] DB_NAME [TBL_NAME ...]
     shell> mysqlcheck [OPTIONS] --databases DB_NAME ...
     shell> mysqlcheck [OPTIONS] --all-databases

If you do not name any tables following DB_NAME or if you use the
`--databases' or `--all-databases' option, entire databases are checked.

*Note `mysqlcheck': mysqlcheck. has a special feature compared to other
client programs. The default behavior of checking tables (`--check')
can be changed by renaming the binary. If you want to have a tool that
repairs tables by default, you should just make a copy of *Note
`mysqlcheck': mysqlcheck. named `mysqlrepair', or make a symbolic link
to *Note `mysqlcheck': mysqlcheck. named `mysqlrepair'. If you invoke
`mysqlrepair', it repairs tables.

The names shown in the following table can be used to change *Note
`mysqlcheck': mysqlcheck. default behavior.

Command            Meaning
`mysqlrepair'      The default option is `--repair'
`mysqlanalyze'     The default option is `--analyze'
`mysqloptimize'    The default option is `--optimize'

*Note `mysqlcheck': mysqlcheck. supports the following options, which
can be specified on the command line or in the `[mysqlcheck]' and
`[client]' groups of an option file. *Note `mysqlcheck': mysqlcheck.
also supports the options for processing option files described at
*Note option-file-options::.

*`mysqlcheck' Options*

Format      Option File Description                   IntroductionDeprecatedRemoved
-all-databasesall-databasesCheck all tables in all                       
                        databases                                     
-all-in-1   all-in-1    Execute a single statement                    
                        for each database that names                  
                        all the  tables from that                     
                        database                                      
-analyze    analyze     Analyze the tables                            
-auto-repairauto-repair If a checked table is                         
                        corrupted, automatically fix                  
                        it                                            
-character-sets-dir=pathcharacter-sets-dirThe directory where                           
                        character sets are installed                  
-check      check       Check the tables for errors                   
-check-only-changedcheck-only-changedCheck only tables that have                   
                        changed since the last check                  
-check-upgradecheck-upgradeInvoke CHECK TABLE with the   5.0.19          
                        FOR UPGRADE option                            
-compress   compress    Compress all information                      
                        sent between the client and                   
                        the server                                    
-databases  databases   Process all tables in the                     
                        named databases                               
-debug[=debug_options]debug       Write a debugging log                         
-default-character-set=charset_namedefault-character-setUse charset_name as the                       
                        default character set                         
-extended   extended    Check and repair tables                       
-fast       fast        Check only tables that have                   
                        not been closed properly                      
-force      force       Continue even if an SQL                       
                        error occurs                                  
-help                   Display help message and exit                 
-host=host_namehost        Connect to the MySQL server                   
                        on the given host                             
-medium-checkmedium-checkDo a check that is faster                     
                        than an -extended operation                   
-optimize   optimize    Optimize the tables                           
-password[=password]password    The password to use when                      
                        connecting to the server                      
-pipe                   On Windows, connect to                        
                        server using a named pipe                     
-port=port_numport        The TCP/IP port number to                     
                        use for the connection                        
-protocol=typeprotocol    The connection protocol to                    
                        use                                           
-quick      quick       The fastest method of                         
                        checking                                      
-repair     repair      Perform a repair that can                     
                        fix almost anything except                    
                        unique keys  that are not                     
                        unique                                        
-silent     silent      Silent mode                                   
-socket=pathsocket      For connections to localhost                  
-ssl-ca=file_namessl-ca      The path to a file that                       
                        contains a list of trusted                    
                        SSL CAs                                       
-ssl-capath=dir_namessl-capath  The path to a directory that                  
                        contains trusted SSL CA                       
                        certificates  in PEM format                   
-ssl-cert=file_namessl-cert    The name of the SSL                           
                        certificate file to use for                   
                        establishing a  secure                        
                        connection                                    
-ssl-cipher=cipher_listssl-cipher  A list of allowable ciphers                   
                        to use for SSL encryption                     
-ssl-key=file_namessl-key     The name of the SSL key file                  
                        to use for establishing a                     
                        secure  connection                            
-ssl-verify-server-certssl-verify-server-certThe server's Common Name                      
                        value in its certificate is                   
                        verified  against the host                    
                        name used when connecting to                  
                        the server                                    
-tables     tables      Overrides the -databases or                   
                        -B option                                     
-use-frm    use-frm     For repair operations on                      
                        MyISAM tables                                 
-user=user_name,user        The MySQL user name to use                    
                        when connecting to the server                 
-verbose                Verbose mode                                  
-version                Display version information                   
                        and exit                                      

   *  `--help', `-?'

     Display a help message and exit.

   *  `--all-databases', `-A'

     Check all tables in all databases. This is the same as using the
     `--databases' option and naming all the databases on the command
     line.

   *  `--all-in-1', `-1'

     Instead of issuing a statement for each table, execute a single
     statement for each database that names all the tables from that
     database to be processed.

   *  `--analyze', `-a'

     Analyze the tables.

   *  `--auto-repair'

     If a checked table is corrupted, automatically fix it. Any
     necessary repairs are done after all tables have been checked.

   *  `--character-sets-dir=PATH'

     The directory where character sets are installed. See *Note
     charset-configuration::.

   *  `--check', `-c'

     Check the tables for errors. This is the default operation.

   *  `--check-only-changed', `-C'

     Check only tables that have changed since the last check or that
     have not been closed properly.

   *  `--check-upgrade', `-g'

     Invoke *Note `CHECK TABLE': check-table. with the `FOR UPGRADE'
     option to check tables for incompatibilities with the current
     version of the server.  This option was added in MySQL 5.0.19.

   *  `--compress'

     Compress all information sent between the client and the server if
     both support compression.

   *  `--databases', `-B'

     Process all tables in the named databases. Normally, *Note
     `mysqlcheck': mysqlcheck. treats the first name argument on the
     command line as a database name and following names as table
     names. With this option, it treats all name arguments as database
     names.

   *  `--debug[=DEBUG_OPTIONS]', `-# [DEBUG_OPTIONS]'

     Write a debugging log. A typical DEBUG_OPTIONS string is
     `'d:t:o,FILE_NAME''.  The default is `'d:t:o''.

   *  `--default-character-set=CHARSET_NAME'

     Use CHARSET_NAME as the default character set. See *Note
     charset-configuration::.

   *  `--extended', `-e'

     If you are using this option to check tables, it ensures that they
     are 100% consistent but takes a long time.

     If you are using this option to repair tables, it runs an extended
     repair that may not only take a long time to execute, but may
     produce a lot of garbage rows also!

   *  `--fast', `-F'

     Check only tables that have not been closed properly.

   *  `--force', `-f'

     Continue even if an SQL error occurs.

   *  `--host=HOST_NAME', `-h HOST_NAME'

     Connect to the MySQL server on the given host.

   *  `--medium-check', `-m'

     Do a check that is faster than an `--extended' operation.  This
     finds only 99.99% of all errors, which should be good enough in
     most cases.

   *  `--optimize', `-o'

     Optimize the tables.

   *  `--password[=PASSWORD]', `-p[PASSWORD]'

     The password to use when connecting to the server. If you use the
     short option form (`-p'), you _cannot_ have a space between the
     option and the password. If you omit the PASSWORD value following
     the `--password' or `-p' option on the command line, *Note
     `mysqlcheck': mysqlcheck. prompts for one.

     Specifying a password on the command line should be considered
     insecure. See *Note password-security-user::. You can use an
     option file to avoid giving the password on the command line.

   *  `--pipe', `-W'

     On Windows, connect to the server using a named pipe. This option
     applies only if the server supports named-pipe connections.

   *  `--port=PORT_NUM', `-P PORT_NUM'

     The TCP/IP port number to use for the connection.

   *  `--protocol={TCP|SOCKET|PIPE|MEMORY}'

     The connection protocol to use for connecting to the server.  It
     is useful when the other connection parameters normally would
     cause a protocol to be used other than the one you want. For
     details on the permissible values, see *Note connecting::.

   *  `--quick', `-q'

     If you are using this option to check tables, it prevents the
     check from scanning the rows to check for incorrect links. This is
     the fastest check method.

     If you are using this option to repair tables, it tries to repair
     only the index tree. This is the fastest repair method.

   *  `--repair', `-r'

     Perform a repair that can fix almost anything except unique keys
     that are not unique.

   *  `--silent', `-s'

     Silent mode. Print only error messages.

   *  `--socket=PATH', `-S PATH'

     For connections to `localhost', the Unix socket file to use, or,
     on Windows, the name of the named pipe to use.

   *  `--ssl*'

     Options that begin with `--ssl' specify whether to connect to the
     server using SSL and indicate where to find SSL keys and
     certificates. See *Note ssl-options::.

   *  `--tables'

     Override the `--databases' or `-B' option. All name arguments
     following the option are regarded as table names.

   *  `--use-frm'

     For repair operations on `MyISAM' tables, get the table structure
     from the `.frm' file so that the table can be repaired even if the
     `.MYI' header is corrupted.

   *  `--user=USER_NAME', `-u USER_NAME'

     The MySQL user name to use when connecting to the server.

   *  `--verbose', `-v'

     Verbose mode. Print information about the various stages of
     program operation.

   *  `--version', `-V'

     Display version information and exit.


File: manual.info,  Node: mysqldump,  Next: mysqlimport,  Prev: mysqlcheck,  Up: programs-client

5.5.4 `mysqldump' -- A Database Backup Program
----------------------------------------------

The *Note `mysqldump': mysqldump. client is a backup program originally
written by Igor Romanenko. It can be used to dump a database or a
collection of databases for backup or transfer to another SQL server
(not necessarily a MySQL server). The dump typically contains SQL
statements to create the table, populate it, or both. However, *Note
`mysqldump': mysqldump. can also be used to generate files in CSV,
other delimited text, or XML format.

If you are doing a backup on the server and your tables all are
`MyISAM' tables, consider using the *Note `mysqlhotcopy': mysqlhotcopy.
instead because it can accomplish faster backups and faster restores.
See *Note mysqlhotcopy::.

There are three general ways to invoke *Note `mysqldump': mysqldump.:

     shell> mysqldump [OPTIONS] DB_NAME [TBL_NAME ...]
     shell> mysqldump [OPTIONS] --databases DB_NAME ...
     shell> mysqldump [OPTIONS] --all-databases

If you do not name any tables following DB_NAME or if you use the
`--databases' or `--all-databases' option, entire databases are dumped.

*Note `mysqldump': mysqldump. does not dump the `INFORMATION_SCHEMA'
database. If you name that database explicitly on the command line,
*Note `mysqldump': mysqldump. silently ignores it.

To see a list of the options your version of *Note `mysqldump':
mysqldump. supports, execute *Note `mysqldump --help': mysqldump.

Some *Note `mysqldump': mysqldump. options are shorthand for groups of
other options:

   * Use of `--opt' is the same as specifying `--add-drop-table',
     `--add-locks', `--create-options', `--disable-keys',
     `--extended-insert', `--lock-tables', `--quick', and
     `--set-charset'. All of the options that `--opt' stands for also
     are on by default because `--opt' is on by default.

   * Use of `--compact' is the same as specifying
     `--skip-add-drop-table', `--skip-add-locks', `--skip-comments',
     `--skip-disable-keys', and `--skip-set-charset' options.

To reverse the effect of a group option, uses its `--skip-XXX' form
(`--skip-opt' or `--skip-compact').  It is also possible to select only
part of the effect of a group option by following it with options that
enable or disable specific features. Here are some examples:

   * To select the effect of `--opt' except for some features, use the
     `--skip' option for each feature. To disable extended inserts and
     memory buffering, use `--opt' `--skip-extended-insert'
     `--skip-quick'.  (Actually, `--skip-extended-insert' `--skip-quick'
     is sufficient because `--opt' is on by default.)

   * To reverse `--opt' for all features except index disabling and
     table locking, use `--skip-opt' `--disable-keys' `--lock-tables'.

When you selectively enable or disable the effect of a group option,
order is important because options are processed first to last. For
example, `--disable-keys' `--lock-tables' `--skip-opt' would not have
the intended effect; it is the same as `--skip-opt' by itself.

*Note `mysqldump': mysqldump. can retrieve and dump table contents row
by row, or it can retrieve the entire content from a table and buffer
it in memory before dumping it. Buffering in memory can be a problem if
you are dumping large tables. To dump tables row by row, use the
`--quick' option (or `--opt', which enables `--quick'). The `--opt'
option (and hence `--quick') is enabled by default, so to enable memory
buffering, use `--skip-quick'.

If you are using a recent version of *Note `mysqldump': mysqldump. to
generate a dump to be reloaded into a very old MySQL server, you should
not use the `--opt' or `--extended-insert' option. Use `--skip-opt'
instead.

Before MySQL 4.1.2, out-of-range numeric values such as `-inf' and
`inf', as well as `NaN' (not-a-number) values are dumped by *Note
`mysqldump': mysqldump. as `NULL'. You can see this using the following
sample table:

     mysql> CREATE TABLE t (f DOUBLE);
     mysql> INSERT INTO t VALUES(1e+111111111111111111111);
     mysql> INSERT INTO t VALUES(-1e111111111111111111111);
     mysql> SELECT f FROM t;
     +------+
     | f    |
     +------+
     |  inf |
     | -inf |
     +------+

For this table, *Note `mysqldump': mysqldump. produces the following
data output:

     --
     -- Dumping data for table `t`
     --

     INSERT INTO t VALUES (NULL);
     INSERT INTO t VALUES (NULL);

The significance of this behavior is that if you dump and restore the
table, the new table has contents that differ from the original
contents. This problem is fixed as of MySQL 4.1.2; you cannot insert
`inf' in the table, so this *Note `mysqldump': mysqldump. behavior is
only relevant when you deal with old servers.

For additional information about *Note `mysqldump': mysqldump, see
*Note using-mysqldump::.

*Note `mysqldump': mysqldump. supports the following options, which can
be specified on the command line or in the `[mysqldump]' and `[client]'
groups of an option file. *Note `mysqldump': mysqldump. also supports
the options for processing option files described at *Note
option-file-options::.

*`mysqldump' Options*

Format      Option File Description                   IntroductionDeprecatedRemoved
-add-drop-databaseadd-drop-databaseAdd a DROP DATABASE                           
                        statement before each CREATE                  
                        DATABASE  statement                           
-add-drop-tableadd-drop-tableAdd a DROP TABLE statement                    
                        before each CREATE TABLE                      
                        statement                                     
-add-locks  add-locks   Surround each table dump                      
                        with LOCK TABLES and UNLOCK                   
                        TABLES  statements                            
-all-databasesall-databasesDump all tables in all                        
                        databases                                     
-allow-keywordsallow-keywordsAllow creation of column                      
                        names that are keywords                       
-comments   comments    Add comments to the dump file                 
-compact    compact     Produce more compact output                   
-compatible=name[,name,...]compatible  Produce output that is more                   
                        compatible with other                         
                        database systems  or with                     
                        older MySQL servers                           
-complete-insertcomplete-insertUse complete INSERT                           
                        statements that include                       
                        column names                                  
-create-optionscreate-optionsInclude all MySQL-specific                    
                        table options in CREATE                       
                        TABLE  statements                             
-databases  databases   Dump several databases                        
-debug[=debug_options]debug       Write a debugging log                         
-debug-info debug-info  Print debugging information,  5.0.32          
                        memory and CPU statistics                     
                        when the  program exits                       
-default-character-set=charset_namedefault-character-setUse charset_name as the                       
                        default character set                         
-delayed-insertdelayed-insertWrite INSERT DELAYED                          
                        statements rather than                        
                        INSERT statements                             
-delete-master-logsdelete-master-logsOn a master replication                       
                        server, delete the binary                     
                        logs after  performing the                    
                        dump operation                                
-disable-keysdisable-keysFor each table, surround the                  
                        INSERT statements with                        
                        statements to  disable and                    
                        enable keys                                   
-dump-date  dump-date   Include dump date as "Dump    5.0.52          
                        completed on" comment if                      
                        -comments is  given                           
-extended-insertextended-insertUse multiple-row INSERT                       
                        syntax that include several                   
                        VALUES lists                                  
-fields-enclosed-by=stringfields-enclosed-byThis option is used with the                  
                        -tab option and has the same                  
                        meaning  as the                               
                        corresponding clause for                      
                        LOAD DATA INFILE                              
-fields-escaped-byfields-escaped-byThis option is used with the                  
                        -tab option and has the same                  
                        meaning  as the                               
                        corresponding clause for                      
                        LOAD DATA INFILE                              
-fields-optionally-enclosed-by=stringfields-optionally-enclosed-byThis option is used with the                  
                        -tab option and has the same                  
                        meaning  as the                               
                        corresponding clause for                      
                        LOAD DATA INFILE                              
-fields-terminated-by=stringfields-terminated-byThis option is used with the                  
                        -tab option and has the same                  
                        meaning  as the                               
                        corresponding clause for                      
                        LOAD DATA INFILE                              
-first-slavefirst-slave Deprecated; use                               
                        -lock-all-tables instead                      
-flush-logs flush-logs  Flush the MySQL server log                    
                        files before starting the                     
                        dump                                          
-flush-privilegesflush-privilegesEmit a FLUSH PRIVILEGES                       
                        statement after dumping the                   
                        mysql database                                
-help                   Display help message and exit                 
-hex-blob   hex-blob    Dump binary columns using                     
                        hexadecimal notation (for                     
                        example, 'abc'  becomes                       
                        0x616263)                                     
-host       host        Host to connect to (IP                        
                        address or hostname)                          
-ignore-table=db_name.tbl_nameignore-tableDo not dump the given table                   
-insert-ignoreinsert-ignoreWrite INSERT IGNORE                           
                        statements rather than                        
                        INSERT statements                             
-lines-terminated-by=stringlines-terminated-byThis option is used with the                  
                        -tab option and has the same                  
                        meaning  as the                               
                        corresponding clause for                      
                        LOAD DATA INFILE                              
-lock-all-tableslock-all-tablesLock all tables across all                    
                        databases                                     
-lock-tableslock-tables Lock all tables before                        
                        dumping them                                  
-log-error=file_namelog-error   Append warnings and errors    5.0.42          
                        to the named file                             
-master-data[=value]master-data Write the binary log file                     
                        name and position to the                      
                        output                                        
-max_allowed_packet=valuemax_allowed_packetThe maximum packet length to                  
                        send to or receive from the                   
                        server                                        
-net_buffer_length=valuenet_buffer_lengthThe buffer size for TCP/IP                    
                        and socket communication                      
-no-autocommitno-autocommitEnclose the INSERT                            
                        statements for each dumped                    
                        table within SET  autocommit                  
                        = 0 and COMMIT statements                     
-no-create-dbno-create-dbThis option suppresses the                    
                        CREATE DATABASE statements                    
-no-create-infono-create-infoDo not write CREATE TABLE                     
                        statements that re-create                     
                        each dumped  table                            
-no-data    no-data     Do not dump table contents                    
-no-set-namesno-set-namesSame as -skip-set-charset                     
-opt        opt         Shorthand for                                 
                        -add-drop-table -add-locks                    
                        -create-options                               
                        -disable-keys                                 
                        -extended-insert                              
                        -lock-tables -quick                           
                        -set-charset.                                 
-order-by-primaryorder-by-primaryDump each table's rows                        
                        sorted by its primary key,                    
                        or by its first  unique index                 
-password[=password]password    The password to use when                      
                        connecting to the server                      
-pipe                   On Windows, connect to                        
                        server using a named pipe                     
-port=port_numport        The TCP/IP port number to                     
                        use for the connection                        
-quick      quick       Retrieve rows for a table                     
                        from the server a row at a                    
                        time                                          
-quote-namesquote-names Quote identifiers within                      
                        backtick characters                           
-result-file=fileresult-file Direct output to a given file                 
-routines   routines    Dump stored routines          5.0.13          
                        (procedures and functions)                    
                        from the dumped  databases                    
-set-charsetset-charset Add SET NAMES                                 
                        default_character_set to the                  
                        output                                        
-single-transactionsingle-transactionThis option issues a BEGIN                    
                        SQL statement before dumping                  
                        data from  the server                         
-skip-add-drop-tableskip-add-drop-tableDo not add a DROP TABLE                       
                        statement before each CREATE                  
                        TABLE  statement                              
-skip-add-locksskip-add-locksDo not add locks                              
-skip-commentsskip-commentsDo not add comments to the                    
                        dump file                                     
-skip-compactskip-compactDo not produce more compact                   
                        output                                        
-skip-disable-keysskip-disable-keysDo not disable keys                           
-skip-extended-insertskip-extended-insertTurn off extended-insert                      
-skip-opt   skip-opt    Turn off the options set by                   
                        -opt                                          
-skip-quick skip-quick  Do not retrieve rows for a                    
                        table from the server a row                   
                        at a time                                     
-skip-quote-namesskip-quote-namesDo not quote identifiers                      
-skip-set-charsetskip-set-charsetSuppress the SET NAMES                        
                        statement                                     
-skip-triggersskip-triggersDo not dump triggers          5.0.11          
-skip-tz-utcskip-tz-utc Turn off tz-utc               5.0.15          
-ssl-ca=file_namessl-ca      The path to a file that                       
                        contains a list of trusted                    
                        SSL CAs                                       
-ssl-capath=dir_namessl-capath  The path to a directory that                  
                        contains trusted SSL CA                       
                        certificates  in PEM format                   
-ssl-cert=file_namessl-cert    The name of the SSL                           
                        certificate file to use for                   
                        establishing a  secure                        
                        connection                                    
-ssl-cipher=cipher_listssl-cipher  A list of allowable ciphers                   
                        to use for SSL encryption                     
-ssl-key=file_namessl-key     The name of the SSL key file                  
                        to use for establishing a                     
                        secure  connection                            
-ssl-verify-server-certssl-verify-server-certThe server's Common Name                      
                        value in its certificate is                   
                        verified  against the host                    
                        name used when connecting to                  
                        the server                                    
-tab=path   tab         Produce tab-separated data                    
                        files                                         
-tables     tables      Override the -databases or                    
                        -B option                                     
-triggers   triggers    Dump triggers for each                        
                        dumped table                                  
-tz-utc     tz-utc      Add SET TIME_ZONE='+00:00'    5.0.15          
                        to the dump file                              
-user=user_nameuser        The MySQL user name to use                    
                        when connecting to the server                 
-verbose                Verbose mode                                  
-version                Display version information                   
                        and exit                                      
-where='where_condition'where       Dump only rows selected by                    
                        the given WHERE condition                     
-xml        xml         Produce XML output                            

   *  `--help', `-?'

     Display a help message and exit.

   *  `--add-drop-database'

     Add a *Note `DROP DATABASE': drop-database. statement before each
     *Note `CREATE DATABASE': create-database.  statement. This option
     is typically used in conjunction with the `--all-databases' or
     `--databases' option because no *Note `CREATE DATABASE':
     create-database. statements are written unless one of those
     options is specified.

   *  `--add-drop-table'

     Add a *Note `DROP TABLE': drop-table. statement before each *Note
     `CREATE TABLE': create-table.  statement.

   *  `--add-locks'

     Surround each table dump with *Note `LOCK TABLES': lock-tables. and
     *Note `UNLOCK TABLES': lock-tables. statements. This results in
     faster inserts when the dump file is reloaded. See *Note
     insert-speed::.

   *  `--all-databases', `-A'

     Dump all tables in all databases. This is the same as using the
     `--databases' option and naming all the databases on the command
     line.

   *  `--allow-keywords'

     Permit creation of column names that are keywords. This works by
     prefixing each column name with the table name.

   *  `--character-sets-dir=PATH'

     The directory where character sets are installed. See *Note
     charset-configuration::.

   *  `--comments', `-i'

     Write additional information in the dump file such as program
     version, server version, and host. This option is enabled by
     default. To suppress this additional information, use
     `--skip-comments'.

   *  `--compact'

     Produce more compact output. This option enables the
     `--skip-add-drop-table', `--skip-add-locks', `--skip-comments',
     `--skip-disable-keys', and `--skip-set-charset' options.

     *Note*:

     Prior to MySQL 5.0.48, this option did not create valid SQL if the
     database dump contained views. The recreation of views requires
     the creation and removal of temporary tables and this option
     suppressed the removal of those temporary tables. As a workaround,
     use `--compact' with the `--add-drop-table' option and then
     manually adjust the dump file.

   *  `--compatible=NAME'

     Produce output that is more compatible with other database systems
     or with older MySQL servers. The value of NAME can be `ansi',
     `mysql323', `mysql40', `postgresql', `oracle', `mssql', `db2',
     `maxdb', `no_key_options', `no_table_options', or
     `no_field_options'. To use several values, separate them by
     commas. These values have the same meaning as the corresponding
     options for setting the server SQL mode. See *Note
     server-sql-mode::.

     This option does not guarantee compatibility with other servers.
     It only enables those SQL mode values that are currently available
     for making dump output more compatible.  For example,
     `--compatible=oracle' does not map data types to Oracle types or
     use Oracle comment syntax.

     _This option requires a server version of 4.1.0 or higher_. With
     older servers, it does nothing.

   *  `--complete-insert', `-c'

     Use complete *Note `INSERT': insert.  statements that include
     column names.

   *  `--compress', `-C'

     Compress all information sent between the client and the server if
     both support compression.

   *  `--create-options'

     Include all MySQL-specific table options in the *Note `CREATE
     TABLE': create-table. statements.

   *  `--databases', `-B'

     Dump several databases. Normally, *Note `mysqldump': mysqldump.
     treats the first name argument on the command line as a database
     name and following names as table names. With this option, it
     treats all name arguments as database names. *Note `CREATE
     DATABASE': create-database. and *Note `USE': use.  statements are
     included in the output before each new database.

   *  `--debug[=DEBUG_OPTIONS]', `-# [DEBUG_OPTIONS]'

     Write a debugging log. A typical DEBUG_OPTIONS string is
     `'d:t:o,FILE_NAME''.  The default value is
     `'d:t:o,/tmp/mysqldump.trace''.

   *  `--debug-info'

     Print debugging information and memory and CPU usage statistics
     when the program exits. This option was added in MySQL 5.0.32.

   *  `--default-character-set=CHARSET_NAME'

     Use CHARSET_NAME as the default character set. See *Note
     charset-configuration::.  If no character set is specified, *Note
     `mysqldump': mysqldump. uses `utf8', and earlier versions use
     `latin1'.

     This option has no effect for output data files produced by using
     the `--tab' option.  See the description for that option.

   *  `--delayed-insert'

     Write *Note `INSERT DELAYED': insert-delayed.  statements rather
     than *Note `INSERT': insert.  statements.

   *  `--delete-master-logs'

     On a master replication server, delete the binary logs by sending
     a *Note `PURGE BINARY LOGS': purge-binary-logs.  statement to the
     server after performing the dump operation.  This option
     automatically enables `--master-data'.

   *  `--disable-keys', `-K'

     For each table, surround the *Note `INSERT': insert. statements
     with `/*!40000 ALTER TABLE TBL_NAME DISABLE KEYS */;' and
     `/*!40000 ALTER TABLE TBL_NAME ENABLE KEYS */;' statements. This
     makes loading the dump file faster because the indexes are created
     after all rows are inserted. This option is effective only for
     nonunique indexes of `MyISAM' tables.

   *  `--dump-date'

     If the `--comments' option is given, *Note `mysqldump': mysqldump.
     produces a comment at the end of the dump of the following form:

          -- Dump completed on DATE

     However, the date causes dump files taken at different times to
     appear to be different, even if the data are otherwise identical.
     `--dump-date' and `--skip-dump-date' control whether the date is
     added to the comment. The default is `--dump-date' (include the
     date in the comment).  `--skip-dump-date' suppresses date
     printing. This option was added in MySQL 5.0.52.

   *  `--extended-insert', `-e'

     Use multiple-row *Note `INSERT': insert.  syntax that include
     several `VALUES' lists.  This results in a smaller dump file and
     speeds up inserts when the file is reloaded.

   *  `--fields-terminated-by=...',

     `--fields-enclosed-by=...',

     `--fields-optionally-enclosed-by=...',

     `--fields-escaped-by=...'

     These options are used with the `--tab' option and have the same
     meaning as the corresponding `FIELDS' clauses for *Note `LOAD DATA
     INFILE': load-data. See *Note load-data::.

   *  `--first-slave'

     Deprecated. Use `--lock-all-tables' instead.  `--first-slave' is
     removed in MySQL 5.5.

   *  `--flush-logs', `-F'

     Flush the MySQL server log files before starting the dump.  This
     option requires the `RELOAD' privilege. If you use this option in
     combination with the `--all-databases' option, the logs are
     flushed _for each database dumped_. The exception is when using
     `--lock-all-tables' or `--master-data': In this case, the logs are
     flushed only once, corresponding to the moment that all tables are
     locked. If you want your dump and the log flush to happen at
     exactly the same moment, you should use `--flush-logs' together
     with either `--lock-all-tables' or `--master-data'.

   *  `--flush-privileges'

     Send a *Note `FLUSH PRIVILEGES': flush. statement to the server
     after dumping the `mysql' database. This option should be used any
     time the dump contains the `mysql' database and any other database
     that depends on the data in the `mysql' database for proper
     restoration. This option was added in MySQL 5.0.26.

   *  `--force', `-f'

     Continue even if an SQL error occurs during a table dump.

     One use for this option is to cause *Note `mysqldump': mysqldump.
     to continue executing even when it encounters a view that has
     become invalid because the definition refers to a table that has
     been dropped. Without `--force', *Note `mysqldump': mysqldump.
     exits with an error message.  With `--force', *Note `mysqldump':
     mysqldump. prints the error message, but it also writes an SQL
     comment containing the view definition to the dump output and
     continues executing.

   *  `--host=HOST_NAME', `-h HOST_NAME'

     Dump data from the MySQL server on the given host. The default
     host is `localhost'.

   *  `--hex-blob'

     Dump binary columns using hexadecimal notation (for example,
     `'abc'' becomes `0x616263'). The affected data types are *Note
     `BINARY': binary-varbinary, *Note `VARBINARY': binary-varbinary,
     and the *Note `BLOB': blob. types. As of MySQL 5.0.13, *Note
     `BIT': numeric-types. columns are affected as well.

   *  `--ignore-table=DB_NAME.TBL_NAME'

     Do not dump the given table, which must be specified using both
     the database and table names. To ignore multiple tables, use this
     option multiple times. This option also can be used to ignore
     views.

   *  `--insert-ignore'

     Write *Note `INSERT IGNORE': insert. statements rather than *Note
     `INSERT': insert. statements.

   *  `--lines-terminated-by=...'

     This option is used with the `--tab' option and has the same
     meaning as the corresponding `LINES' clause for *Note `LOAD DATA
     INFILE': load-data. See *Note load-data::.

   *  `--lock-all-tables', `-x'

     Lock all tables across all databases. This is achieved by
     acquiring a global read lock for the duration of the whole dump.
     This option automatically turns off `--single-transaction' and
     `--lock-tables'.

   *  `--lock-tables', `-l'

     For each dumped database, lock all tables to be dumped before
     dumping them. The tables are locked with `READ LOCAL' to permit
     concurrent inserts in the case of `MyISAM' tables. For
     transactional tables such as `InnoDB' and `BDB',
     `--single-transaction' is a much better option than
     `--lock-tables' because it does not need to lock the tables at all.

     Because `--lock-tables' locks tables for each database separately,
     this option does not guarantee that the tables in the dump file
     are logically consistent between databases. Tables in different
     databases may be dumped in completely different states.

   *  `--log-error=FILE_NAME'

     Log warnings and errors by appending them to the named file.  The
     default is to do no logging. This option was added in MySQL 5.0.42.

   *  `--master-data[=VALUE]'

     Use this option to dump a master replication server to produce a
     dump file that can be used to set up another server as a slave of
     the master. It causes the dump output to include a *Note `CHANGE
     MASTER TO': change-master-to.  statement that indicates the binary
     log coordinates (file name and position) of the dumped server.
     These are the master server coordinates from which the slave
     should start replicating after you load the dump file into the
     slave.

     If the option value is 2, the *Note `CHANGE MASTER TO':
     change-master-to. statement is written as an SQL comment, and thus
     is informative only; it has no effect when the dump file is
     reloaded. If the option value is 1, the statement is not written
     as a comment and takes effect when the dump file is reloaded. If
     no option value is specified, the default value is 1.

     This option requires the `RELOAD' privilege and the binary log
     must be enabled.

     The `--master-data' option automatically turns off
     `--lock-tables'. It also turns on `--lock-all-tables', unless
     `--single-transaction' also is specified, in which case, a global
     read lock is acquired only for a short time at the beginning of
     the dump (see the description for `--single-transaction'). In all
     cases, any action on logs happens at the exact moment of the dump.

     It is also possible to set up a slave by dumping an existing slave
     of the master. To do this, use the following procedure on the
     existing slave:

       1. Stop the slave's SQL thread and get its current status:

               mysql> STOP SLAVE SQL_THREAD;
               mysql> SHOW SLAVE STATUS;

       2. From the output of the *Note `SHOW SLAVE STATUS':
          show-slave-status. statement, the binary log coordinates of
          the master server from which the new slave should start
          replicating are the values of the `Relay_Master_Log_File' and
          `Exec_Master_Log_Pos' fields. Denote those values as
          FILE_NAME and FILE_POS.

       3. Dump the slave server:

               shell> mysqldump --master-data=2 --all-databases > dumpfile

          Using `--master-data=2' works only if binary logging has been
          enabled on the slave. Otherwise, *Note `mysqldump':
          mysqldump. fails with the error `Binlogging on server not
          active'.  In this case you must handle any locking issues in
          another manner, using one or more of `--add-locks',
          `--lock-tables', `--lock-all-tables', or
          `--single-transaction', as required by your application and
          environment.

       4. Restart the slave:

               mysql> START SLAVE;

       5. On the new slave, load the dump file:

               shell> mysql < dumpfile

       6. On the new slave, set the replication coordinates to those of
          the master server obtained earlier:

               mysql> CHANGE MASTER TO
                   -> MASTER_LOG_FILE = 'FILE_NAME', MASTER_LOG_POS = FILE_POS;

          The *Note `CHANGE MASTER TO': change-master-to.  statement
          might also need other parameters, such as `MASTER_HOST' to
          point the slave to the correct master server host. Add any
          such parameters as necessary.

   *  `--no-autocommit'

     Enclose the *Note `INSERT': insert. statements for each dumped
     table within `SET autocommit = 0' and *Note `COMMIT': commit.
     statements.

   *  `--no-create-db', `-n'

     This option suppresses the *Note `CREATE DATABASE':
     create-database. statements that are otherwise included in the
     output if the `--databases' or `--all-databases' option is given.

   *  `--no-create-info', `-t'

     Do not write *Note `CREATE TABLE': create-table.  statements that
     re-create each dumped table.

   *  `--no-data', `-d'

     Do not write any table row information (that is, do not dump table
     contents). This is useful if you want to dump only the *Note
     `CREATE TABLE': create-table. statement for the table (for
     example, to create an empty copy of the table by loading the dump
     file).

   *  `--no-set-names', `-N'

     This has the same effect as `--skip-set-charset'.

   *  `--opt'

     This option is shorthand. It is the same as specifying
     `--add-drop-table' `--add-locks' `--create-options'
     `--disable-keys' `--extended-insert' `--lock-tables' `--quick'
     `--set-charset'. It should give you a fast dump operation and
     produce a dump file that can be reloaded into a MySQL server
     quickly.

     _The `--opt' option is enabled by default. Use `--skip-opt' to
     disable it._ See the discussion at the beginning of this section
     for information about selectively enabling or disabling a subset
     of the options affected by `--opt'.

   *  `--order-by-primary'

     Dump each table's rows sorted by its primary key, or by its first
     unique index, if such an index exists. This is useful when dumping
     a `MyISAM' table to be loaded into an `InnoDB' table, but will
     make the dump operation take considerably longer.

   *  `--password[=PASSWORD]', `-p[PASSWORD]'

     The password to use when connecting to the server. If you use the
     short option form (`-p'), you _cannot_ have a space between the
     option and the password. If you omit the PASSWORD value following
     the `--password' or `-p' option on the command line, *Note
     `mysqldump': mysqldump. prompts for one.

     Specifying a password on the command line should be considered
     insecure. See *Note password-security-user::. You can use an
     option file to avoid giving the password on the command line.

   *  `--pipe', `-W'

     On Windows, connect to the server using a named pipe. This option
     applies only if the server supports named-pipe connections.

   *  `--port=PORT_NUM', `-P PORT_NUM'

     The TCP/IP port number to use for the connection.

   *  `--protocol={TCP|SOCKET|PIPE|MEMORY}'

     The connection protocol to use for connecting to the server.  It
     is useful when the other connection parameters normally would
     cause a protocol to be used other than the one you want. For
     details on the permissible values, see *Note connecting::.

   *  `--quick', `-q'

     This option is useful for dumping large tables. It forces *Note
     `mysqldump': mysqldump. to retrieve rows for a table from the
     server a row at a time rather than retrieving the entire row set
     and buffering it in memory before writing it out.

   *  `--quote-names', `-Q'

     Quote identifiers (such as database, table, and column names)
     within ```'' characters. If the `ANSI_QUOTES' SQL mode is enabled,
     identifiers are quoted within ``"'' characters. This option is
     enabled by default. It can be disabled with `--skip-quote-names',
     but this option should be given after any option such as
     `--compatible' that may enable `--quote-names'.

   *  `--result-file=FILE_NAME', `-r FILE_NAME'

     Direct output to a given file. This option should be used on
     Windows to prevent newline ``\n'' characters from being converted
     to ``\r\n'' carriage return/newline sequences. The result file is
     created and its previous contents overwritten, even if an error
     occurs while generating the dump.

   *  `--routines', `-R'

     Included stored routines (procedures and functions) for the dumped
     databases in the output. Use of this option requires the `SELECT'
     privilege for the `mysql.proc' table. The output generated by
     using `--routines' contains *Note `CREATE PROCEDURE':
     create-procedure. and *Note `CREATE FUNCTION': create-function.
     statements to re-create the routines. However, these statements do
     not include attributes such as the routine creation and
     modification timestamps. This means that when the routines are
     reloaded, they will be created with the timestamps equal to the
     reload time.

     If you require routines to be re-created with their original
     timestamp attributes, do not use `--routines'. Instead, dump and
     reload the contents of the `mysql.proc' table directly, using a
     MySQL account that has appropriate privileges for the `mysql'
     database.

     This option was added in MySQL 5.0.13. Before that, stored
     routines are not dumped. Routine `DEFINER' values are not dumped
     until MySQL 5.0.20. This means that before 5.0.20, when routines
     are reloaded, they will be created with the definer set to the
     reloading user. If you require routines to be re-created with
     their original definer, dump and load the contents of the
     `mysql.proc' table directly as described earlier.

   *  `--set-charset'

     Add `SET NAMES DEFAULT_CHARACTER_SET' to the output. This option
     is enabled by default. To suppress the `SET NAMES' statement, use
     `--skip-set-charset'.

   *  `--single-transaction'

     This option sends a *Note `START TRANSACTION': commit. SQL
     statement to the server before dumping data. It is useful only
     with transactional tables such as `InnoDB' and `BDB', because then
     it dumps the consistent state of the database at the time when
     *Note `BEGIN': commit. was issued without blocking any
     applications.

     When using this option, you should keep in mind that only `InnoDB'
     tables are dumped in a consistent state. For example, any `MyISAM'
     or `MEMORY' tables dumped while using this option may still change
     state.

     While a `--single-transaction' dump is in process, to ensure a
     valid dump file (correct table contents and binary log
     coordinates), no other connection should use the following
     statements: *Note `ALTER TABLE': alter-table, *Note `CREATE
     TABLE': create-table, *Note `DROP TABLE': drop-table, *Note
     `RENAME TABLE': rename-table, *Note `TRUNCATE TABLE':
     truncate-table. A consistent read is not isolated from those
     statements, so use of them on a table to be dumped can cause the
     *Note `SELECT': select. that is performed by *Note `mysqldump':
     mysqldump. to retrieve the table contents to obtain incorrect
     contents or fail.

     The `--single-transaction' option and the `--lock-tables' option
     are mutually exclusive because *Note `LOCK TABLES': lock-tables.
     causes any pending transactions to be committed implicitly.

     This option is not supported for MySQL Cluster tables; the results
     cannot be guaranteed to be consistent due to the fact that the
     *Note `NDBCLUSTER': mysql-cluster.  storage engine supports only
     the `READ_COMMITTED' transaction isolation level. You should
     always use *Note `NDB': mysql-cluster. backup and restore instead.

     To dump large tables, you should combine the `--single-transaction'
     option with `--quick'.

   *  `--skip-comments'

     See the description for the `--comments' option.

   *  `--skip-opt'

     See the description for the `--opt' option.

   *  `--socket=PATH', `-S PATH'

     For connections to `localhost', the Unix socket file to use, or,
     on Windows, the name of the named pipe to use.

   *  `--ssl*'

     Options that begin with `--ssl' specify whether to connect to the
     server using SSL and indicate where to find SSL keys and
     certificates. See *Note ssl-options::.

   *  `--tab=PATH', `-T PATH'

     Produce tab-separated text-format data files. For each dumped
     table, *Note `mysqldump': mysqldump. creates a `TBL_NAME.sql' file
     that contains the *Note `CREATE TABLE': create-table. statement
     that creates the table, and the server writes a `TBL_NAME.txt'
     file that contains its data. The option value is the directory in
     which to write the files.

     *Note*:

     This option should be used only when *Note `mysqldump': mysqldump.
     is run on the same machine as the *Note `mysqld': mysqld. server.
     You must have the `FILE' privilege, and the server must have
     permission to write files in the directory that you specify.

     By default, the `.txt' data files are formatted using tab
     characters between column values and a newline at the end of each
     line. The format can be specified explicitly using the
     `--fields-XXX' and `--lines-terminated-by' options.

     Column values are dumped using the `binary' character set and the
     `--default-character-set' option is ignored. In effect, there is
     no character set conversion. If a table contains columns in
     several character sets, the output data file will as well and you
     may not be able to reload the file correctly.

   *  `--tables'

     Override the `--databases' or `-B' option. *Note `mysqldump':
     mysqldump.  regards all name arguments following the option as
     table names.

   *  `--triggers'

     Include triggers for each dumped table in the output. This option
     is enabled by default; disable it with `--skip-triggers'.  This
     option was added in MySQL 5.0.11. Before that, triggers are not
     dumped.

   *  `--tz-utc'

     This option enables *Note `TIMESTAMP': datetime.  columns to be
     dumped and reloaded between servers in different time zones. *Note
     `mysqldump': mysqldump. sets its connection time zone to UTC and
     adds `SET TIME_ZONE='+00:00'' to the dump file. Without this
     option, *Note `TIMESTAMP': datetime. columns are dumped and
     reloaded in the time zones local to the source and destination
     servers, which can cause the values to change if the servers are
     in different time zones.  `--tz-utc' also protects against changes
     due to daylight saving time.  `--tz-utc' is enabled by default. To
     disable it, use `--skip-tz-utc'.  This option was added in MySQL
     5.0.15.

   *  `--user=USER_NAME', `-u USER_NAME'

     The MySQL user name to use when connecting to the server.

   *  `--verbose', `-v'

     Verbose mode. Print more information about what the program does.

   *  `--version', `-V'

     Display version information and exit.

   *  `--where='WHERE_CONDITION'', `-w 'WHERE_CONDITION''

     Dump only rows selected by the given `WHERE' condition. Quotes
     around the condition are mandatory if it contains spaces or other
     characters that are special to your command interpreter.

     Examples:

          --where="user='jimf'"
          -w"userid>1"
          -w"userid<1"

   *  `--xml', `-X'

     Write dump output as well-formed XML.

     *`NULL', `'NULL'', and Empty Values*: For a column named
     COLUMN_NAME, the `NULL' value, an empty string, and the string
     value `'NULL'' are distinguished from one another in the output
     generated by this option as follows.

     Value:                             XML Representation:
     `NULL' (_unknown value_)           `<field name="COLUMN_NAME"
                                        xsi:nil="true" />'
     `''' (_empty string_)              `<field
                                        name="COLUMN_NAME"></field>'
     `'NULL'' (_string value_)          `<field
                                        name="COLUMN_NAME">NULL</field>'

     Beginning with MySQL 5.0.26, the output from the *Note `mysql':
     mysql. client when run using the `--xml' option also follows the
     preceding rules. (See *Note mysql-command-options::.)

     Beginning with MySQL 5.0.40, XML output from *Note `mysqldump':
     mysqldump. includes the XML namespace, as shown here:

          shell> mysqldump --xml -u root world City
          <?xml version="1.0"?>
          <mysqldump xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance">
          <database name="world">
          <table_structure name="City">
          <field Field="ID" Type="int(11)" Null="NO" Key="PRI" Extra="auto_increment" />
          <field Field="Name" Type="char(35)" Null="NO" Key="" Default="" Extra="" />
          <field Field="CountryCode" Type="char(3)" Null="NO" Key="" Default="" Extra="" />
          <field Field="District" Type="char(20)" Null="NO" Key="" Default="" Extra="" />
          <field Field="Population" Type="int(11)" Null="NO" Key="" Default="0" Extra="" />
          <key Table="City" Non_unique="0" Key_name="PRIMARY" Seq_in_index="1" Column_name="ID"
          Collation="A" Cardinality="4079" Null="" Index_type="BTREE" Comment="" />
          <options Name="City" Engine="MyISAM" Version="10" Row_format="Fixed" Rows="4079"
          Avg_row_length="67" Data_length="273293" Max_data_length="18858823439613951"
          Index_length="43008" Data_free="0" Auto_increment="4080"
          Create_time="2007-03-31 01:47:01" Update_time="2007-03-31 01:47:02"
          Collation="latin1_swedish_ci" Create_options="" Comment="" />
          </table_structure>
          <table_data name="City">
          <row>
          <field name="ID">1</field>
          <field name="Name">Kabul</field>
          <field name="CountryCode">AFG</field>
          <field name="District">Kabol</field>
          <field name="Population">1780000</field>
          </row>

          ...

          <row>
          <field name="ID">4079</field>
          <field name="Name">Rafah</field>
          <field name="CountryCode">PSE</field>
          <field name="District">Rafah</field>
          <field name="Population">92020</field>
          </row>
          </table_data>
          </database>
          </mysqldump>

You can also set the following variables by using `--VAR_NAME=VALUE'
syntax:

   * `max_allowed_packet'

     The maximum size of the buffer for client/server communication.
     The maximum is 1GB.

   *  `net_buffer_length'

     The initial size of the buffer for client/server communication.
     When creating multiple-row *Note `INSERT': insert. statements (as
     with the `--extended-insert' or `--opt' option), *Note
     `mysqldump': mysqldump. creates rows up to `net_buffer_length'
     length.  If you increase this variable, you should also ensure that
     the `net_buffer_length' variable in the MySQL server is at least
     this large.

It is also possible to set variables by using `--VAR_NAME=VALUE'.  The
`--set-variable' format is deprecated.

A common use of *Note `mysqldump': mysqldump. is for making a backup of
an entire database:

     shell> mysqldump DB_NAME > BACKUP-FILE.SQL

You can load the dump file back into the server like this:

     shell> mysql DB_NAME < BACKUP-FILE.SQL

Or like this:

     shell> mysql -e "source /PATH-TO-BACKUP/BACKUP-FILE.SQL" DB_NAME

*Note `mysqldump': mysqldump. is also very useful for populating
databases by copying data from one MySQL server to another:

     shell> mysqldump --opt DB_NAME | mysql --host=REMOTE_HOST -C DB_NAME

It is possible to dump several databases with one command:

     shell> mysqldump --databases DB_NAME1 [DB_NAME2 ...] > my_databases.sql

To dump all databases, use the `--all-databases' option:

     shell> mysqldump --all-databases > all_databases.sql

For `InnoDB' tables, *Note `mysqldump': mysqldump. provides a way of
making an online backup:

     shell> mysqldump --all-databases --single-transaction > all_databases.sql

This backup acquires a global read lock on all tables (using *Note
`FLUSH TABLES WITH READ LOCK': flush.) at the beginning of the dump. As
soon as this lock has been acquired, the binary log coordinates are
read and the lock is released. If long updating statements are running
when the *Note `FLUSH': flush. statement is issued, the MySQL server
may get stalled until those statements finish. After that, the dump
becomes lock free and does not disturb reads and writes on the tables.
If the update statements that the MySQL server receives are short (in
terms of execution time), the initial lock period should not be
noticeable, even with many updates.

For point-in-time recovery (also known as `roll-forward,' when you need
to restore an old backup and replay the changes that happened since
that backup), it is often useful to rotate the binary log (see *Note
binary-log::) or at least know the binary log coordinates to which the
dump corresponds:

     shell> mysqldump --all-databases --master-data=2 > all_databases.sql

Or:

     shell> mysqldump --all-databases --flush-logs --master-data=2
                   > all_databases.sql

The `--master-data' and `--single-transaction' options can be used
simultaneously, which provides a convenient way to make an online
backup suitable for use prior to point-in-time recovery if tables are
stored using the `InnoDB' storage engine.

For more information on making backups, see *Note backup-methods::, and
*Note backup-strategy-example::.

If you encounter problems backing up views, please read the section
that covers restrictions on views which describes a workaround for
backing up views when this fails due to insufficient privileges. See
*Note view-restrictions::.


File: manual.info,  Node: mysqlimport,  Next: mysqlshow,  Prev: mysqldump,  Up: programs-client

5.5.5 `mysqlimport' -- A Data Import Program
--------------------------------------------

The *Note `mysqlimport': mysqlimport. client provides a command-line
interface to the *Note `LOAD DATA INFILE': load-data. SQL statement.
Most options to *Note `mysqlimport': mysqlimport. correspond directly
to clauses of *Note `LOAD DATA INFILE': load-data. syntax. See *Note
load-data::.

Invoke *Note `mysqlimport': mysqlimport. like this:

     shell> mysqlimport [OPTIONS] DB_NAME TEXTFILE1 [TEXTFILE2 ...]

For each text file named on the command line, *Note `mysqlimport':
mysqlimport. strips any extension from the file name and uses the
result to determine the name of the table into which to import the
file's contents. For example, files named `patient.txt',
`patient.text', and `patient' all would be imported into a table named
`patient'.

*Note `mysqlimport': mysqlimport. supports the following options, which
can be specified on the command line or in the `[mysqlimport]' and
`[client]' groups of an option file. *Note `mysqlimport': mysqlimport.
also supports the options for processing option files described at
*Note option-file-options::.

*`mysqlimport' Options*

Format      Option File Description                   IntroductionDeprecatedRemoved
-columns=column_listcolumns     This option takes a                           
                        comma-separated list of                       
                        column names as its  value                    
-compress   compress    Compress all information                      
                        sent between the client and                   
                        the server                                    
-debug[=debug_options]debug       Write a debugging log                         
-default-character-set=charset_namedefault-character-setUse charset_name as the                       
                        default character set                         
-delete     delete      Empty the table before                        
                        importing the text file                       
-fields-enclosed-by=stringfields-enclosed-byThis option has the same                      
                        meaning as the corresponding                  
                        clause for  LOAD DATA INFILE                  
-fields-escaped-byfields-escaped-byThis option has the same                      
                        meaning as the corresponding                  
                        clause for  LOAD DATA INFILE                  
-fields-optionally-enclosed-by=stringfields-optionally-enclosed-byThis option has the same                      
                        meaning as the corresponding                  
                        clause for  LOAD DATA INFILE                  
-fields-terminated-by=stringfields-terminated-by- This option has the same                    
                        meaning as the corresponding                  
                        clause  for LOAD DATA INFILE                  
-force      force       Continue even if an SQL                       
                        error occurs                                  
-help                   Display help message and exit                 
-host=host_namehost        Connect to the MySQL server                   
                        on the given host                             
-ignore     ignore      See the description for the                   
                        -replace option                               
-ignore-lines=#ignore-linesIgnore the first N lines of                   
                        the data file                                 
-lines-terminated-by=stringlines-terminated-byThis option has the same                      
                        meaning as the corresponding                  
                        clause for  LOAD DATA INFILE                  
-local      local       Read input files locally                      
                        from the client host                          
-lock-tableslock-tables Lock all tables for writing                   
                        before processing any text                    
                        files                                         
-low-prioritylow-priorityUse LOW_PRIORITY when                         
                        loading the table.                            
-password[=password]password    The password to use when                      
                        connecting to the server                      
-pipe                   On Windows, connect to                        
                        server using a named pipe                     
-port=port_numport        The TCP/IP port number to                     
                        use for the connection                        
-protocol=typeprotocol    The connection protocol to                    
                        use                                           
-replace    replace     The -replace and -ignore                      
                        options control handling of                   
                        input rows  that duplicate                    
                        existing rows on unique key                   
                        values                                        
-silent     silent      Produce output only when                      
                        errors occur                                  
-socket=pathsocket      For connections to localhost                  
-ssl-ca=file_namessl-ca      The path to a file that                       
                        contains a list of trusted                    
                        SSL CAs                                       
-ssl-capath=dir_namessl-capath  The path to a directory that                  
                        contains trusted SSL CA                       
                        certificates  in PEM format                   
-ssl-cert=file_namessl-cert    The name of the SSL                           
                        certificate file to use for                   
                        establishing a  secure                        
                        connection                                    
-ssl-cipher=cipher_listssl-cipher  A list of allowable ciphers                   
                        to use for SSL encryption                     
-ssl-key=file_namessl-key     The name of the SSL key file                  
                        to use for establishing a                     
                        secure  connection                            
-ssl-verify-server-certssl-verify-server-certThe server's Common Name                      
                        value in its certificate is                   
                        verified  against the host                    
                        name used when connecting to                  
                        the server                                    
-user=user_name,user        The MySQL user name to use                    
                        when connecting to the server                 
-verbose                Verbose mode                                  
-version                Display version information                   
                        and exit                                      

   *  `--help', `-?'

     Display a help message and exit.

   *  `--character-sets-dir=PATH'

     The directory where character sets are installed. See *Note
     charset-configuration::.

   *  `--columns=COLUMN_LIST', `-c COLUMN_LIST'

     This option takes a comma-separated list of column names as its
     value. The order of the column names indicates how to match data
     file columns with table columns.

   *  `--compress', `-C'

     Compress all information sent between the client and the server if
     both support compression.

   *  `--debug[=DEBUG_OPTIONS]', `-# [DEBUG_OPTIONS]'

     Write a debugging log. A typical DEBUG_OPTIONS string is
     `'d:t:o,FILE_NAME''.  The default is `'d:t:o''.

   *  `--default-character-set=CHARSET_NAME'

     Use CHARSET_NAME as the default character set. See *Note
     charset-configuration::.

   *  `--delete', `-D'

     Empty the table before importing the text file.

   *  `--fields-terminated-by=...',

     `--fields-enclosed-by=...',

     `--fields-optionally-enclosed-by=...',

     `--fields-escaped-by=...'

     These options have the same meaning as the corresponding clauses
     for *Note `LOAD DATA INFILE': load-data. See *Note load-data::.

   *  `--force', `-f'

     Ignore errors. For example, if a table for a text file does not
     exist, continue processing any remaining files. Without `--force',
     *Note `mysqlimport': mysqlimport. exits if a table does not exist.

   *  `--host=HOST_NAME', `-h HOST_NAME'

     Import data to the MySQL server on the given host. The default
     host is `localhost'.

   *  `--ignore', `-i'

     See the description for the `--replace' option.

   *  `--ignore-lines=N'

     Ignore the first N lines of the data file.

   *  `--lines-terminated-by=...'

     This option has the same meaning as the corresponding clause for
     *Note `LOAD DATA INFILE': load-data. For example, to import
     Windows files that have lines terminated with carriage
     return/linefeed pairs, use `--lines-terminated-by="\r\n"'.  (You
     might have to double the backslashes, depending on the escaping
     conventions of your command interpreter.) See *Note load-data::.

   *  `--local', `-L'

     Read input files locally from the client host.

   *  `--lock-tables', `-l'

     Lock _all_ tables for writing before processing any text files.
     This ensures that all tables are synchronized on the server.

   *  `--low-priority'

     Use `LOW_PRIORITY' when loading the table.  This affects only
     storage engines that use only table-level locking (such as
     `MyISAM', `MEMORY', and `MERGE').

   *  `--password[=PASSWORD]', `-p[PASSWORD]'

     The password to use when connecting to the server. If you use the
     short option form (`-p'), you _cannot_ have a space between the
     option and the password. If you omit the PASSWORD value following
     the `--password' or `-p' option on the command line, *Note
     `mysqlimport': mysqlimport. prompts for one.

     Specifying a password on the command line should be considered
     insecure. See *Note password-security-user::. You can use an
     option file to avoid giving the password on the command line.

   *  `--pipe', `-W'

     On Windows, connect to the server using a named pipe. This option
     applies only if the server supports named-pipe connections.

   *  `--port=PORT_NUM', `-P PORT_NUM'

     The TCP/IP port number to use for the connection.

   *  `--protocol={TCP|SOCKET|PIPE|MEMORY}'

     The connection protocol to use for connecting to the server.  It
     is useful when the other connection parameters normally would
     cause a protocol to be used other than the one you want. For
     details on the permissible values, see *Note connecting::.

   *  `--replace', `-r'

     The `--replace' and `--ignore' options control handling of input
     rows that duplicate existing rows on unique key values. If you
     specify `--replace', new rows replace existing rows that have the
     same unique key value.  If you specify `--ignore', input rows that
     duplicate an existing row on a unique key value are skipped. If
     you do not specify either option, an error occurs when a duplicate
     key value is found, and the rest of the text file is ignored.

   *  `--silent', `-s'

     Silent mode. Produce output only when errors occur.

   *  `--socket=PATH', `-S PATH'

     For connections to `localhost', the Unix socket file to use, or,
     on Windows, the name of the named pipe to use.

   *  `--ssl*'

     Options that begin with `--ssl' specify whether to connect to the
     server using SSL and indicate where to find SSL keys and
     certificates. See *Note ssl-options::.

   *  `--user=USER_NAME', `-u USER_NAME'

     The MySQL user name to use when connecting to the server.

   *  `--verbose', `-v'

     Verbose mode. Print more information about what the program does.

   *  `--version', `-V'

     Display version information and exit.

Here is a sample session that demonstrates use of *Note `mysqlimport':
mysqlimport.:

     shell> mysql -e 'CREATE TABLE imptest(id INT, n VARCHAR(30))' test
     shell> ed
     a
     100     Max Sydow
     101     Count Dracula
     .
     w imptest.txt
     32
     q
     shell> od -c imptest.txt
     0000000   1   0   0  \t   M   a   x       S   y   d   o   w  \n   1   0
     0000020   1  \t   C   o   u   n   t       D   r   a   c   u   l   a  \n
     0000040
     shell> mysqlimport --local test imptest.txt
     test.imptest: Records: 2  Deleted: 0  Skipped: 0  Warnings: 0
     shell> mysql -e 'SELECT * FROM imptest' test
     +------+---------------+
     | id   | n             |
     +------+---------------+
     |  100 | Max Sydow     |
     |  101 | Count Dracula |
     +------+---------------+


File: manual.info,  Node: mysqlshow,  Prev: mysqlimport,  Up: programs-client

5.5.6 `mysqlshow' -- Display Database, Table, and Column Information
--------------------------------------------------------------------

The *Note `mysqlshow': mysqlshow. client can be used to quickly see
which databases exist, their tables, or a table's columns or indexes.

*Note `mysqlshow': mysqlshow. provides a command-line interface to
several SQL *Note `SHOW': show. statements.  See *Note show::. The same
information can be obtained by using those statements directly. For
example, you can issue them from the *Note `mysql': mysql. client
program.

Invoke *Note `mysqlshow': mysqlshow. like this:

     shell> mysqlshow [OPTIONS] [DB_NAME [TBL_NAME [COL_NAME]]]

   * If no database is given, a list of database names is shown.

   * If no table is given, all matching tables in the database are
     shown.

   * If no column is given, all matching columns and column types in
     the table are shown.

The output displays only the names of those databases, tables, or
columns for which you have some privileges.

If the last argument contains shell or SQL wildcard characters (``*'',
``?'', ``%'', or ``_''), only those names that are matched by the
wildcard are shown. If a database name contains any underscores, those
should be escaped with a backslash (some Unix shells require two) to
get a list of the proper tables or columns. ``*'' and ``?'' characters
are converted into SQL ``%'' and ``_'' wildcard characters. This might
cause some confusion when you try to display the columns for a table
with a ``_'' in the name, because in this case, *Note `mysqlshow':
mysqlshow. shows you only the table names that match the pattern. This
is easily fixed by adding an extra ``%'' last on the command line as a
separate argument.

*Note `mysqlshow': mysqlshow. supports the following options, which can
be specified on the command line or in the `[mysqlshow]' and `[client]'
groups of an option file. *Note `mysqlshow': mysqlshow. also supports
the options for processing option files described at *Note
option-file-options::.

*`mysqlshow' Options*

Format      Option File Description                   IntroductionDeprecatedRemoved
-compress   compress    Compress all information                      
                        sent between the client and                   
                        the server                                    
-count      count       Show the number of rows per   5.0.6           
                        table                                         
-debug[=debug_options]debug       Write a debugging log                         
-default-character-set=charset_namedefault-character-setUse charset_name as the                       
                        default character set                         
-help                   Display help message and exit                 
-host=host_namehost        Connect to the MySQL server                   
                        on the given host                             
-keys       keys        Show table indexes                            
-password[=password]password    The password to use when                      
                        connecting to the server                      
-pipe                   On Windows, connect to                        
                        server using a named pipe                     
-port=port_numport        The TCP/IP port number to                     
                        use for the connection                        
-protocol=typeprotocol    The connection protocol to                    
                        use                                           
-show-table-type            Show a column indicating the  5.0.4           
                        table type                                    
-socket=pathsocket      For connections to localhost                  
-ssl-ca=file_namessl-ca      The path to a file that                       
                        contains a list of trusted                    
                        SSL CAs                                       
-ssl-capath=dir_namessl-capath  The path to a directory that                  
                        contains trusted SSL CA                       
                        certificates  in PEM format                   
-ssl-cert=file_namessl-cert    The name of the SSL                           
                        certificate file to use for                   
                        establishing a  secure                        
                        connection                                    
-ssl-cipher=cipher_listssl-cipher  A list of allowable ciphers                   
                        to use for SSL encryption                     
-ssl-key=file_namessl-key     The name of the SSL key file                  
                        to use for establishing a                     
                        secure  connection                            
-ssl-verify-server-certssl-verify-server-certThe server's Common Name                      
                        value in its certificate is                   
                        verified  against the host                    
                        name used when connecting to                  
                        the server                                    
-status     status      Display extra information                     
                        about each table                              
-user=user_name,user        The MySQL user name to use                    
                        when connecting to the server                 
-verbose                Verbose mode                                  
-version                Display version information                   
                        and exit                                      

   *  `--help', `-?'

     Display a help message and exit.

   *  `--character-sets-dir=PATH'

     The directory where character sets are installed. See *Note
     charset-configuration::.

   *  `--compress', `-C'

     Compress all information sent between the client and the server if
     both support compression.

   *  `--count'

     Show the number of rows per table. This can be slow for
     non-`MyISAM' tables. This option was added in MySQL 5.0.6.

   *  `--debug[=DEBUG_OPTIONS]', `-# [DEBUG_OPTIONS]'

     Write a debugging log. A typical DEBUG_OPTIONS string is
     `'d:t:o,FILE_NAME''.  The default is `'d:t:o''.

   *  `--default-character-set=CHARSET_NAME'

     Use CHARSET_NAME as the default character set. See *Note
     charset-configuration::.

   *  `--host=HOST_NAME', `-h HOST_NAME'

     Connect to the MySQL server on the given host.

   *  `--keys', `-k'

     Show table indexes.

   *  `--password[=PASSWORD]', `-p[PASSWORD]'

     The password to use when connecting to the server. If you use the
     short option form (`-p'), you _cannot_ have a space between the
     option and the password. If you omit the PASSWORD value following
     the `--password' or `-p' option on the command line, *Note
     `mysqlshow': mysqlshow. prompts for one.

     Specifying a password on the command line should be considered
     insecure. See *Note password-security-user::. You can use an
     option file to avoid giving the password on the command line. You
     can use an option file to avoid giving the password on the command
     line.

   *  `--pipe', `-W'

     On Windows, connect to the server using a named pipe. This option
     applies only if the server supports named-pipe connections.

   *  `--port=PORT_NUM', `-P PORT_NUM'

     The TCP/IP port number to use for the connection.

   *  `--protocol={TCP|SOCKET|PIPE|MEMORY}'

     The connection protocol to use for connecting to the server.  It
     is useful when the other connection parameters normally would
     cause a protocol to be used other than the one you want. For
     details on the permissible values, see *Note connecting::.

   *  `--show-table-type', `-t'

     Show a column indicating the table type, as in *Note `SHOW FULL
     TABLES': show-tables. The type is `BASE TABLE' or `VIEW'. This
     option was added in MySQL 5.0.4.

   *  `--socket=PATH', `-S PATH'

     For connections to `localhost', the Unix socket file to use, or,
     on Windows, the name of the named pipe to use.

   *  `--ssl*'

     Options that begin with `--ssl' specify whether to connect to the
     server using SSL and indicate where to find SSL keys and
     certificates. See *Note ssl-options::.

   *  `--status', `-i'

     Display extra information about each table.

   *  `--user=USER_NAME', `-u USER_NAME'

     The MySQL user name to use when connecting to the server.

   *  `--verbose', `-v'

     Verbose mode. Print more information about what the program does.
     This option can be used multiple times to increase the amount of
     information.

   *  `--version', `-V'

     Display version information and exit.


File: manual.info,  Node: programs-admin-utils,  Next: programs-development,  Prev: programs-client,  Up: programs

5.6 MySQL Administrative and Utility Programs
=============================================

* Menu:

* innochecksum::                 `innochecksum' --- Offline InnoDB File Checksum Utility
* myisam-ftdump::                `myisam_ftdump' --- Display Full-Text Index information
* myisamchk::                    `myisamchk' --- MyISAM Table-Maintenance Utility
* myisamlog::                    `myisamlog' --- Display MyISAM Log File Contents
* myisampack::                   `myisampack' --- Generate Compressed, Read-Only MyISAM Tables
* mysqlaccess::                  `mysqlaccess' --- Client for Checking Access Privileges
* mysqlbinlog::                  `mysqlbinlog' --- Utility for Processing Binary Log Files
* mysqldumpslow::                `mysqldumpslow' --- Summarize Slow Query Log Files
* mysqlhotcopy::                 `mysqlhotcopy' --- A Database Backup Program
* instance-manager::             `mysqlmanager' --- The MySQL Instance Manager
* mysql-convert-table-format::   `mysql_convert_table_format' --- Convert Tables to Use a Given Storage Engine
* mysql-explain-log::            `mysql_explain_log' --- Use EXPLAIN on Statements in Query Log
* mysql-find-rows::              `mysql_find_rows' --- Extract SQL Statements from Files
* mysql-fix-extensions::         `mysql_fix_extensions' --- Normalize Table File Name Extensions
* mysql-setpermission::          `mysql_setpermission' --- Interactively Set Permissions in Grant Tables
* mysql-tableinfo::              `mysql_tableinfo' --- Generate Database Metadata
* mysql-waitpid::                `mysql_waitpid' --- Kill Process and Wait for Its Termination
* mysql-zap::                    `mysql_zap' --- Kill Processes That Match a Pattern

This section describes administrative programs and programs that
perform miscellaneous utility operations.


File: manual.info,  Node: innochecksum,  Next: myisam-ftdump,  Prev: programs-admin-utils,  Up: programs-admin-utils

5.6.1 `innochecksum' -- Offline InnoDB File Checksum Utility
------------------------------------------------------------

*Note `innochecksum': innochecksum. prints checksums for `InnoDB'
files. This tool reads an `InnoDB' tablespace file, calculates the
checksum for each page, compares the calculated checksum to the stored
checksum, and reports mismatches, which indicate damaged pages. It was
originally developed to speed up verifying the integrity of tablespace
files after power outages but can also be used after file copies.
Because checksum mismatches will cause `InnoDB' to deliberately shut
down a running server, it can be preferable to use this tool rather
than waiting for a server in production usage to encounter the damaged
pages.

*Note `innochecksum': innochecksum. cannot be used on tablespace files
that the server already has open. For such files, you should use *Note
`CHECK TABLE': check-table. to check tables within the tablespace.

If checksum mismatches are found, you would normally restore the
tablespace from backup or start the server and attempt to use *Note
`mysqldump': mysqldump. to make a backup of the tables within the
tablespace.

Invoke *Note `innochecksum': innochecksum. like this:

     shell> innochecksum [OPTIONS] FILE_NAME

*Note `innochecksum': innochecksum. supports the following options.
For options that refer to page numbers, the numbers are zero-based.

   *  `-c'

     Print a count of the number of pages in the file.

   *  `-d'

     Debug mode; prints checksums for each page.

   *  `-e NUM'

     End at this page number.

   *  `-p NUM'

     Check only this page number.

   *  `-s NUM'

     Start at this page number.

   *  `-v'

     Verbose mode; print a progress indicator every five seconds.


File: manual.info,  Node: myisam-ftdump,  Next: myisamchk,  Prev: innochecksum,  Up: programs-admin-utils

5.6.2 `myisam_ftdump' -- Display Full-Text Index information
------------------------------------------------------------

*Note `myisam_ftdump': myisam-ftdump. displays information about
`FULLTEXT' indexes in `MyISAM' tables. It reads the `MyISAM' index file
directly, so it must be run on the server host where the table is
located. Before using *Note `myisam_ftdump': myisam-ftdump, be sure to
issue a `FLUSH TABLES' statement first if the server is running.

*Note `myisam_ftdump': myisam-ftdump. scans and dumps the entire index,
which is not particularly fast. On the other hand, the distribution of
words changes infrequently, so it need not be run often.

Invoke *Note `myisam_ftdump': myisam-ftdump. like this:

     shell> myisam_ftdump [OPTIONS] TBL_NAME INDEX_NUM

The TBL_NAME argument should be the name of a `MyISAM' table. You can
also specify a table by naming its index file (the file with the `.MYI'
suffix). If you do not invoke *Note `myisam_ftdump': myisam-ftdump. in
the directory where the table files are located, the table or index
file name must be preceded by the path name to the table's database
directory.  Index numbers begin with 0.

Example: Suppose that the `test' database contains a table named
`mytexttablel' that has the following definition:

     CREATE TABLE mytexttable
     (
       id   INT NOT NULL,
       txt  TEXT NOT NULL,
       PRIMARY KEY (id),
       FULLTEXT (txt)
     ) ENGINE=MyISAM;

The index on `id' is index 0 and the `FULLTEXT' index on `txt' is index
1. If your working directory is the `test' database directory, invoke
*Note `myisam_ftdump': myisam-ftdump. as follows:

     shell> myisam_ftdump mytexttable 1

If the path name to the `test' database directory is
`/usr/local/mysql/data/test', you can also specify the table name
argument using that path name. This is useful if you do not invoke
*Note `myisam_ftdump': myisam-ftdump. in the database directory:

     shell> myisam_ftdump /usr/local/mysql/data/test/mytexttable 1

You can use *Note `myisam_ftdump': myisam-ftdump. to generate a list of
index entries in order of frequency of occurrence like this:

     shell> myisam_ftdump -c mytexttable 1 | sort -r

*Note `myisam_ftdump': myisam-ftdump. supports the following options:

   *  `--help', `-h' `-?'

     Display a help message and exit.

   *  `--count', `-c'

     Calculate per-word statistics (counts and global weights).

   *  `--dump', `-d'

     Dump the index, including data offsets and word weights.

   *  `--length', `-l'

     Report the length distribution.

   *  `--stats', `-s'

     Report global index statistics. This is the default operation if
     no other operation is specified.

   *  `--verbose', `-v'

     Verbose mode. Print more output about what the program does.


File: manual.info,  Node: myisamchk,  Next: myisamlog,  Prev: myisam-ftdump,  Up: programs-admin-utils

5.6.3 `myisamchk' -- MyISAM Table-Maintenance Utility
-----------------------------------------------------

* Menu:

* myisamchk-general-options::    `myisamchk' General Options
* myisamchk-check-options::      `myisamchk' Check Options
* myisamchk-repair-options::     `myisamchk' Repair Options
* myisamchk-other-options::      Other `myisamchk' Options
* myisamchk-table-info::         Obtaining Table Information with `myisamchk'
* myisamchk-memory::             `myisamchk' Memory Usage

The *Note `myisamchk': myisamchk. utility gets information about your
database tables or checks, repairs, or optimizes them.  *Note
`myisamchk': myisamchk. works with `MyISAM' tables (tables that have
`.MYD' and `.MYI' files for storing data and indexes).

You can also use the *Note `CHECK TABLE': check-table.  and *Note
`REPAIR TABLE': repair-table. statements to check and repair `MyISAM'
tables. See *Note check-table::, and *Note repair-table::.

*Caution*:

It is best to make a backup of a table before performing a table repair
operation; under some circumstances the operation might cause data
loss. Possible causes include but are not limited to file system errors.

Invoke *Note `myisamchk': myisamchk. like this:

     shell> myisamchk [OPTIONS] TBL_NAME ...

The OPTIONS specify what you want *Note `myisamchk': myisamchk. to do.
They are described in the following sections. You can also get a list
of options by invoking *Note `myisamchk --help': myisamchk.

With no options, *Note `myisamchk': myisamchk. simply checks your table
as the default operation. To get more information or to tell *Note
`myisamchk': myisamchk. to take corrective action, specify options as
described in the following discussion.

TBL_NAME is the database table you want to check or repair. If you run
*Note `myisamchk': myisamchk.  somewhere other than in the database
directory, you must specify the path to the database directory, because
*Note `myisamchk': myisamchk. has no idea where the database is
located. In fact, *Note `myisamchk': myisamchk. does not actually care
whether the files you are working on are located in a database
directory. You can copy the files that correspond to a database table
into some other location and perform recovery operations on them there.

You can name several tables on the *Note `myisamchk': myisamchk.
command line if you wish. You can also specify a table by naming its
index file (the file with the `.MYI' suffix). This enables you to
specify all tables in a directory by using the pattern `*.MYI'. For
example, if you are in a database directory, you can check all the
`MyISAM' tables in that directory like this:

     shell> myisamchk *.MYI

If you are not in the database directory, you can check all the tables
there by specifying the path to the directory:

     shell> myisamchk /PATH/TO/DATABASE_DIR/*.MYI

You can even check all tables in all databases by specifying a wildcard
with the path to the MySQL data directory:

     shell> myisamchk /PATH/TO/DATADIR/*/*.MYI

The recommended way to quickly check all `MyISAM' tables is:

     shell> myisamchk --silent --fast /PATH/TO/DATADIR/*/*.MYI

If you want to check all `MyISAM' tables and repair any that are
corrupted, you can use the following command:

     shell> myisamchk --silent --force --fast --update-state \
               --key_buffer_size=64M --sort_buffer_size=64M \
               --read_buffer_size=1M --write_buffer_size=1M \
               /PATH/TO/DATADIR/*/*.MYI

This command assumes that you have more than 64MB free. For more
information about memory allocation with *Note `myisamchk': myisamchk,
see *Note myisamchk-memory::.

For additional information about using *Note `myisamchk': myisamchk, see
*Note myisam-table-maintenance::.

*Important*:

_You must ensure that no other program is using the tables while you
are running *Note `myisamchk': myisamchk._. The most effective means of
doing so is to shut down the MySQL server while running *Note
`myisamchk': myisamchk, or to lock all tables that *Note `myisamchk':
myisamchk. is being used on.

Otherwise, when you run *Note `myisamchk': myisamchk, it may display
the following error message:

     warning: clients are using or haven't closed the table properly

This means that you are trying to check a table that has been updated
by another program (such as the *Note `mysqld': mysqld. server) that
hasn't yet closed the file or that has died without closing the file
properly, which can sometimes lead to the corruption of one or more
`MyISAM' tables.

If *Note `mysqld': mysqld. is running, you must force it to flush any
table modifications that are still buffered in memory by using *Note
`FLUSH TABLES': flush. You should then ensure that no one is using the
tables while you are running *Note `myisamchk': myisamchk.

However, the easiest way to avoid this problem is to use *Note `CHECK
TABLE': check-table. instead of *Note `myisamchk': myisamchk. to check
tables. See *Note check-table::.

*Note `myisamchk': myisamchk. supports the following options, which can
be specified on the command line or in the `[myisamchk]' group of an
option file.  *Note `myisamchk': myisamchk. also supports the options
for processing option files described at *Note option-file-options::.

*`myisamchk' Options*

Format      Option File Description                   IntroductionDeprecatedRemoved
-analyze    analyze     Analyze the distribution of                   
                        key values                                    
-backup     backup      Make a backup of the .MYD                     
                        file as file_name-time.BAK                    
-block-search=offsetblock-searchFind the record that a block                  
                        at the given offset belongs                   
                        to                                            
-check      check       Check the table for errors                    
-check-only-changedcheck-only-changedCheck only tables that have                   
                        changed since the last check                  
-correct-checksumcorrect-checksumCorrect the checksum                          
                        information for the table                     
-data-file-length=lendata-file-lengthMaximum length of the data                    
                        file (when re-creating data                   
                        file when  it is full)                        
-debug[=debug_options]debug       Write a debugging log                         
decode_bits=#decode_bits Decode_bits                                   
-descriptiondescription Print some descriptive                        
                        information about the table                   
-extend-checkextend-checkDo very thorough table check                  
                        or repair that tries to                       
                        recover every  possible row                   
                        from the data file                            
-fast       fast        Check only tables that                        
                        haven't been closed properly                  
-force      force       Do a repair operation                         
                        automatically if myisamchk                    
                        finds any errors  in the                      
                        table                                         
-force      force-recoverOverwrite old temporary                       
                        files. For use with the -r                    
                        or -o option                                  
ft_max_word_len=#ft_max_word_lenMaximum word length for                       
                        FULLTEXT indexes                              
ft_min_word_len=#ft_min_word_lenMinimum word length for                       
                        FULLTEXT indexes                              
ft_stopword_file=valueft_stopword_fileUse stopwords from this file                  
                        instead of built-in list                      
-HELP                   Display help message and exit                 
-help                   Display help message and exit                 
-informationinformation Print informational                           
                        statistics about the table                    
                        that is checked                               
key_buffer_size=#key_buffer_sizeThe size of the buffer used                   
                        for index blocks for MyISAM                   
                        tables                                        
-keys-used=valkeys-used   A bit-value that indicates                    
                        which indexes to update                       
-max-record-length=lenmax-record-lengthSkip rows larger than the                     
                        given length if myisamchk                     
                        cannot  allocate memory to                    
                        hold them                                     
-medium-checkmedium-checkDo a check that is faster                     
                        than an -extend-check                         
                        operation                                     
myisam_block_size=#myisam_block_sizeBlock size to be used for                     
                        MyISAM index pages                            
-parallel-recoverparallel-recoverUses the same technique as                    
                        -r and -n, but creates all                    
                        the keys in  parallel, using                  
                        different threads (beta)                      
-quick      quick       Achieve a faster repair by                    
                        not modifying the data file.                  
read_buffer_size=#read_buffer_sizeEach thread that does a                       
                        sequential scan allocates a                   
                        buffer of this  size for                      
                        each table it scans                           
-read-only  read-only   Don't mark the table as                       
                        checked                                       
-recover    recover     Do a repair that can fix                      
                        almost any problem except                     
                        unique keys  that aren't                      
                        unique                                        
-safe-recoversafe-recoverDo a repair using an old                      
                        recovery method that reads                    
                        through all  rows in order                    
                        and updates all index trees                   
                        based on the rows found                       
-set-auto-increment[=value]set-auto-incrementForce AUTO_INCREMENT                          
                        numbering for new records to                  
                        start at the  given value                     
-set-character-set=nameset-character-setChange the character set                      
                        used by the table indexes                     
-set-collation=nameset-collationSpecify the collation to use                  
                        for sorting table indexes                     
-silent     silent      Silent mode                                   
sort_buffer_size=#sort_buffer_sizeThe buffer that is allocated                  
                        when sorting the index when                   
                        doing a  REPAIR or when                       
                        creating indexes with CREATE                  
                        INDEX or ALTER TABLE                          
-sort-index sort-index  Sort the index tree blocks                    
                        in high-low order                             
sort_key_blocks=#sort_key_blockssort_key_blocks                               
-sort-records=#sort-recordsSort records according to a                   
                        particular index                              
-sort-recoversort-recoverForce myisamchk to use                        
                        sorting to resolve the keys                   
                        even if the  temporary files                  
                        would be very large                           
stats_method=valuestats_methodSpecifies how MyISAM index                    
                        statistics collection code                    
                        should treat  NULLs                           
-tmpdir=pathtmpdir      Path of the directory to be                   
                        used for storing temporary                    
                        files                                         
-unpack     unpack      Unpack a table that was                       
                        packed with myisampack                        
-update-stateupdate-stateStore information in the                      
                        .MYI file to indicate when                    
                        the table was  checked and                    
                        whether the table crashed                     
-verbose                Verbose mode                                  
-version                Display version information                   
                        and exit                                      
write_buffer_size=#write_buffer_sizeWrite buffer size                             


File: manual.info,  Node: myisamchk-general-options,  Next: myisamchk-check-options,  Prev: myisamchk,  Up: myisamchk

5.6.3.1 `myisamchk' General Options
...................................

The options described in this section can be used for any type of table
maintenance operation performed by *Note `myisamchk': myisamchk. The
sections following this one describe options that pertain only to
specific operations, such as table checking or repairing.

   *  `--help', `-?'

     Display a help message and exit. Options are grouped by type of
     operation.

   *  `--HELP', `-H'

     Display a help message and exit. Options are presented in a single
     list.

   *  `--debug=DEBUG_OPTIONS', `-# DEBUG_OPTIONS'

     Write a debugging log. A typical DEBUG_OPTIONS string is
     `'d:t:o,FILE_NAME''.  The default is
     `'d:t:o,/tmp/myisamchk.trace''.

   *  `--silent', `-s'

     Silent mode. Write output only when errors occur. You can use `-s'
     twice (`-ss') to make *Note `myisamchk': myisamchk. very silent.

   *  `--verbose', `-v'

     Verbose mode. Print more information about what the program does.
     This can be used with `-d' and `-e'. Use `-v' multiple times
     (`-vv', `-vvv') for even more output.

   *  `--version', `-V'

     Display version information and exit.

   *  `--wait', `-w'

     Instead of terminating with an error if the table is locked, wait
     until the table is unlocked before continuing. If you are running
     *Note `mysqld': mysqld. with external locking disabled, the table
     can be locked only by another *Note `myisamchk': myisamchk.
     command.

You can also set the following variables by using `--VAR_NAME=VALUE'
syntax:

Variable                  Default Value
`decode_bits'             9
`ft_max_word_len'         version-dependent
`ft_min_word_len'         4
`ft_stopword_file'        built-in list
`key_buffer_size'         523264
`myisam_block_size'       1024
`read_buffer_size'        262136
`sort_buffer_size'        2097144
`sort_key_blocks'         16
`stats_method'            nulls_unequal
`write_buffer_size'       262136

It is also possible to set variables by using
`--set-variable=VAR_NAME=VALUE' or `-O VAR_NAME=VALUE' syntax. However,
this syntax is deprecated as of MySQL 4.0.

The possible *Note `myisamchk': myisamchk. variables and their default
values can be examined with *Note `myisamchk --help': myisamchk.:

`sort_buffer_size' is used when the keys are repaired by sorting keys,
which is the normal case when you use `--recover'.

`key_buffer_size' is used when you are checking the table with
`--extend-check' or when the keys are repaired by inserting keys row by
row into the table (like when doing normal inserts). Repairing through
the key buffer is used in the following cases:

   * You use `--safe-recover'.

   * The temporary files needed to sort the keys would be more than
     twice as big as when creating the key file directly.  This is
     often the case when you have large key values for *Note `CHAR':
     char, *Note `VARCHAR': char, or *Note `TEXT': blob. columns,
     because the sort operation needs to store the complete key values
     as it proceeds. If you have lots of temporary space and you can
     force *Note `myisamchk': myisamchk. to repair by sorting, you can
     use the `--sort-recover' option.

Repairing through the key buffer takes much less disk space than using
sorting, but is also much slower.

If you want a faster repair, set the `key_buffer_size' and
`sort_buffer_size' variables to about 25% of your available memory. You
can set both variables to large values, because only one of them is
used at a time.

`myisam_block_size' is the size used for index blocks.

`stats_method' influences how `NULL' values are treated for index
statistics collection when the `--analyze' option is given. It acts
like the `myisam_stats_method' system variable. For more information,
see the description of `myisam_stats_method' in *Note
server-system-variables::, and *Note myisam-index-statistics::. For
MySQL 5.0, `stats_method' was added in MySQL 5.0.14. For older
versions, the statistics collection method is equivalent to
`nulls_equal'.

`ft_min_word_len' and `ft_max_word_len' indicate the minimum and
maximum word length for `FULLTEXT' indexes.  `ft_stopword_file' names
the stopword file.  These need to be set under the following
circumstances.

If you use *Note `myisamchk': myisamchk. to perform an operation that
modifies table indexes (such as repair or analyze), the `FULLTEXT'
indexes are rebuilt using the default full-text parameter values for
minimum and maximum word length and the stopword file unless you
specify otherwise. This can result in queries failing.

The problem occurs because these parameters are known only by the
server. They are not stored in `MyISAM' index files. To avoid the
problem if you have modified the minimum or maximum word length or the
stopword file in the server, specify the same `ft_min_word_len',
`ft_max_word_len', and `ft_stopword_file' values to *Note `myisamchk':
myisamchk. that you use for *Note `mysqld': mysqld. For example, if you
have set the minimum word length to 3, you can repair a table with
*Note `myisamchk': myisamchk. like this:

     shell> myisamchk --recover --ft_min_word_len=3 TBL_NAME.MYI

To ensure that *Note `myisamchk': myisamchk. and the server use the
same values for full-text parameters, you can place each one in both
the `[mysqld]' and `[myisamchk]' sections of an option file:

     [mysqld]
     ft_min_word_len=3

     [myisamchk]
     ft_min_word_len=3

An alternative to using *Note `myisamchk': myisamchk. is to use the
*Note `REPAIR TABLE': repair-table, *Note `ANALYZE TABLE':
analyze-table, *Note `OPTIMIZE TABLE': optimize-table, or *Note `ALTER
TABLE': alter-table. These statements are performed by the server,
which knows the proper full-text parameter values to use.


File: manual.info,  Node: myisamchk-check-options,  Next: myisamchk-repair-options,  Prev: myisamchk-general-options,  Up: myisamchk

5.6.3.2 `myisamchk' Check Options
.................................

*Note `myisamchk': myisamchk. supports the following options for table
checking operations:

   *  `--check', `-c'

     Check the table for errors. This is the default operation if you
     specify no option that selects an operation type explicitly.

   *  `--check-only-changed', `-C'

     Check only tables that have changed since the last check.

   *  `--extend-check', `-e'

     Check the table very thoroughly. This is quite slow if the table
     has many indexes. This option should only be used in extreme
     cases. Normally, *Note `myisamchk': myisamchk. or *Note `myisamchk
     --medium-check': myisamchk. should be able to determine whether
     there are any errors in the table.

     If you are using `--extend-check' and have plenty of memory,
     setting the `key_buffer_size' variable to a large value helps the
     repair operation run faster.

     See also the description of this option under table repair options.

     For a description of the output format, see *Note
     myisamchk-table-info::.

   *  `--fast', `-F'

     Check only tables that haven't been closed properly.

   *  `--force', `-f'

     Do a repair operation automatically if *Note `myisamchk':
     myisamchk. finds any errors in the table.  The repair type is the
     same as that specified with the `--recover' or `-r' option.

   *  `--information', `-i'

     Print informational statistics about the table that is checked.

   *  `--medium-check', `-m'

     Do a check that is faster than an `--extend-check' operation.
     This finds only 99.99% of all errors, which should be good enough
     in most cases.

   *  `--read-only', `-T'

     Do not mark the table as checked. This is useful if you use *Note
     `myisamchk': myisamchk. to check a table that is in use by some
     other application that does not use locking, such as *Note
     `mysqld': mysqld. when run with external locking disabled.

   *  `--update-state', `-U'

     Store information in the `.MYI' file to indicate when the table
     was checked and whether the table crashed. This should be used to
     get full benefit of the `--check-only-changed' option, but you
     shouldn't use this option if the *Note `mysqld': mysqld. server is
     using the table and you are running it with external locking
     disabled.


File: manual.info,  Node: myisamchk-repair-options,  Next: myisamchk-other-options,  Prev: myisamchk-check-options,  Up: myisamchk

5.6.3.3 `myisamchk' Repair Options
..................................

*Note `myisamchk': myisamchk. supports the following options for table
repair operations (operations performed when an option such as
`--recover' or `--safe-recover' is given):

   *  `--backup', `-B'

     Make a backup of the `.MYD' file as `FILE_NAME-TIME.BAK'

   *  `--character-sets-dir=PATH'

     The directory where character sets are installed. See *Note
     charset-configuration::.

   *  `--correct-checksum'

     Correct the checksum information for the table.

   *  `--data-file-length=LEN', `-D LEN'

     The maximum length of the data file (when re-creating data file
     when it is `full').

   * `--extend-check', `-e'

     Do a repair that tries to recover every possible row from the data
     file. Normally, this also finds a lot of garbage rows. Do not use
     this option unless you are desperate.

     See also the description of this option under table checking
     options.

     For a description of the output format, see *Note
     myisamchk-table-info::.

   * `--force', `-f'

     Overwrite old intermediate files (files with names like
     `TBL_NAME.TMD') instead of aborting.

   *  `--keys-used=VAL', `-k VAL'

     For *Note `myisamchk': myisamchk, the option value is a bit-value
     that indicates which indexes to update. Each binary bit of the
     option value corresponds to a table index, where the first index
     is bit 0. An option value of 0 disables updates to all indexes,
     which can be used to get faster inserts. Deactivated indexes can
     be reactivated by using *Note `myisamchk -r': myisamchk.

   *  `--no-symlinks', `-l'

     Do not follow symbolic links. Normally *Note `myisamchk':
     myisamchk. repairs the table that a symlink points to. This option
     does not exist as of MySQL 4.0 because versions from 4.0 on do not
     remove symlinks during repair operations.

   *  `--max-record-length=LEN'

     Skip rows larger than the given length if *Note `myisamchk':
     myisamchk. cannot allocate memory to hold them.

   *  `--parallel-recover', `-p'

     Use the same technique as `-r' and `-n', but create all the keys
     in parallel, using different threads. _This is beta-quality code.
     Use at your own risk!_

   *  `--quick', `-q'

     Achieve a faster repair by modifying only the index file, not the
     data file. You can specify this option twice to force *Note
     `myisamchk': myisamchk. to modify the original data file in case
     of duplicate keys.

   *  `--recover', `-r'

     Do a repair that can fix almost any problem except unique keys
     that are not unique (which is an extremely unlikely error with
     `MyISAM' tables). If you want to recover a table, this is the
     option to try first. You should try `--safe-recover' only if *Note
     `myisamchk': myisamchk. reports that the table cannot be recovered
     using `--recover'. (In the unlikely case that `--recover' fails,
     the data file remains intact.)

     If you have lots of memory, you should increase the value of
     `sort_buffer_size'.

   *  `--safe-recover', `-o'

     Do a repair using an old recovery method that reads through all
     rows in order and updates all index trees based on the rows found.
     This is an order of magnitude slower than `--recover', but can
     handle a couple of very unlikely cases that `--recover' cannot.
     This recovery method also uses much less disk space than
     `--recover'. Normally, you should repair first using `--recover',
     and then with `--safe-recover' only if `--recover' fails.

     If you have lots of memory, you should increase the value of
     `key_buffer_size'.

   *  `--set-character-set=NAME'

     Change the character set used by the table indexes. This option
     was replaced by `--set-collation' in MySQL 5.0.3.

   *  `--set-collation=NAME'

     Specify the collation to use for sorting table indexes. The
     character set name is implied by the first part of the collation
     name. This option was added in MySQL 5.0.3.

   *  `--sort-recover', `-n'

     Force *Note `myisamchk': myisamchk. to use sorting to resolve the
     keys even if the temporary files would be very large.

   *  `--tmpdir=PATH', `-t PATH'

     The path of the directory to be used for storing temporary files.
     If this is not set, *Note `myisamchk': myisamchk. uses the value
     of the `TMPDIR' environment variable. `--tmpdir' can be set to a
     list of directory paths that are used successively in round-robin
     fashion for creating temporary files. The separator character
     between directory names is the colon (``:'') on Unix and the
     semicolon (``;'') on Windows, NetWare, and OS/2.

   *  `--unpack', `-u'

     Unpack a table that was packed with *Note `myisampack': myisampack.


File: manual.info,  Node: myisamchk-other-options,  Next: myisamchk-table-info,  Prev: myisamchk-repair-options,  Up: myisamchk

5.6.3.4 Other `myisamchk' Options
.................................

*Note `myisamchk': myisamchk. supports the following options for
actions other than table checks and repairs:

   *  `--analyze', `-a'

     Analyze the distribution of key values. This improves join
     performance by enabling the join optimizer to better choose the
     order in which to join the tables and which indexes it should use.
     To obtain information about the key distribution, use a *Note
     `myisamchk --description --verbose TBL_NAME': myisamchk.  command
     or the `SHOW INDEX FROM TBL_NAME' statement.

   *  `--block-search=OFFSET', `-b OFFSET'

     Find the record that a block at the given offset belongs to.

   *  `--description', `-d'

     Print some descriptive information about the table.  Specifying
     the `--verbose' option once or twice produces additional
     information. See *Note myisamchk-table-info::.

   *  `--set-auto-increment[=VALUE]', `-A[VALUE]'

     Force `AUTO_INCREMENT' numbering for new records to start at the
     given value (or higher, if there are existing records with
     `AUTO_INCREMENT' values this large). If VALUE is not specified,
     `AUTO_INCREMENT' numbers for new records begin with the largest
     value currently in the table, plus one.

   *  `--sort-index', `-S'

     Sort the index tree blocks in high-low order. This optimizes seeks
     and makes table scans that use indexes faster.

   *  `--sort-records=N', `-R N'

     Sort records according to a particular index. This makes your data
     much more localized and may speed up range-based *Note `SELECT':
     select. and `ORDER BY' operations that use this index. (The first
     time you use this option to sort a table, it may be very slow.)
     To determine a table's index numbers, use *Note `SHOW INDEX':
     show-index, which displays a table's indexes in the same order that
     *Note `myisamchk': myisamchk. sees them. Indexes are numbered
     beginning with 1.

     If keys are not packed (`PACK_KEYS=0'), they have the same length,
     so when *Note `myisamchk': myisamchk. sorts and moves records, it
     just overwrites record offsets in the index. If keys are packed
     (`PACK_KEYS=1'), *Note `myisamchk': myisamchk. must unpack key
     blocks first, then re-create indexes and pack the key blocks
     again. (In this case, re-creating indexes is faster than updating
     offsets for each index.)


File: manual.info,  Node: myisamchk-table-info,  Next: myisamchk-memory,  Prev: myisamchk-other-options,  Up: myisamchk

5.6.3.5 Obtaining Table Information with `myisamchk'
....................................................

To obtain a description of a `MyISAM' table or statistics about it, use
the commands shown here. The output from these commands is explained
later in this section.

   * *Note `myisamchk -d TBL_NAME': myisamchk.

     Runs *Note `myisamchk': myisamchk. in `describe mode' to produce a
     description of your table. If you start the MySQL server with
     external locking disabled, *Note `myisamchk': myisamchk. may
     report an error for a table that is updated while it runs.
     However, because *Note `myisamchk': myisamchk. does not change the
     table in describe mode, there is no risk of destroying data.

   * *Note `myisamchk -dv TBL_NAME': myisamchk.

     Adding `-v' runs *Note `myisamchk': myisamchk.  in verbose mode so
     that it produces more information about the table. Adding `-v' a
     second time produces even more information.

   * *Note `myisamchk -eis TBL_NAME': myisamchk.

     Shows only the most important information from a table. This
     operation is slow because it must read the entire table.

   * *Note `myisamchk -eiv TBL_NAME': myisamchk.

     This is like `-eis', but tells you what is being done.

The TBL_NAME argument can be either the name of a `MyISAM' table or the
name of its index file, as described in *Note myisamchk::.  Multiple
TBL_NAME arguments can be given.

Suppose that a table named `person' has the following structure. (The
`MAX_ROWS' table option is included so that in the example output from
*Note `myisamchk': myisamchk. shown later, some values are smaller and
fit the output format more easily.)

     CREATE TABLE person
     (
       id         INT NOT NULL AUTO_INCREMENT,
       last_name  VARCHAR(20) NOT NULL,
       first_name VARCHAR(20) NOT NULL,
       birth      DATE,
       death      DATE,
       PRIMARY KEY (id),
       INDEX (last_name, first_name),
       INDEX (birth)
     ) MAX_ROWS = 1000000;

Suppose also that the table has these data and index file sizes:

     -rw-rw----  1 mysql  mysql  9347072 Aug 19 11:47 person.MYD
     -rw-rw----  1 mysql  mysql  6066176 Aug 19 11:47 person.MYI

Example of *Note `myisamchk -dvv': myisamchk. output:

     MyISAM file:         person
     Record format:       Packed
     Character set:       latin1_swedish_ci (8)
     File-version:        1
     Creation time:       2009-08-19 16:47:41
     Recover time:        2009-08-19 16:47:56
     Status:              checked,analyzed,optimized keys
     Auto increment key:              1  Last value:                306688
     Data records:               306688  Deleted blocks:                 0
     Datafile parts:             306688  Deleted data:                   0
     Datafile pointer (bytes):        4  Keyfile pointer (bytes):        3
     Datafile length:           9347072  Keyfile length:           6066176
     Max datafile length:    4294967294  Max keyfile length:   17179868159
     Recordlength:                   54

     table description:
     Key Start Len Index   Type                 Rec/key         Root  Blocksize
     1   2     4   unique  long                       1        99328       1024
     2   6     20  multip. varchar prefix           512      3563520       1024
         27    20          varchar                  512
     3   48    3   multip. uint24 NULL           306688      6065152       1024

     Field Start Length Nullpos Nullbit Type
     1     1     1
     2     2     4                      no zeros
     3     6     21                     varchar
     4     27    21                     varchar
     5     48    3      1       1       no zeros
     6     51    3      1       2       no zeros

Explanations for the types of information *Note `myisamchk': myisamchk.
produces are given here.  `Keyfile' refers to the index file.  `Record'
and `row' are synonymous, as are `field' and `column.'

The initial part of the table description contains these values:

   * `MyISAM file'

     Name of the `MyISAM' (index) file.

   * `Record format'

     The format used to store table rows. The preceding examples use
     `Fixed length'. Other possible values are `Compressed' and
     `Packed'. (`Packed' corresponds to what `SHOW TABLE STATUS'
     reports as `Dynamic'.)

   * `Chararacter set'

     The table default character set.

   * `File-version'

     Version of `MyISAM' format. Currently always 1.

   * `Creation time'

     When the data file was created.

   * `Recover time'

     When the index/data file was last reconstructed.

   * `Status'

     Table status flags. Possible values are `crashed', `open',
     `changed', `analyzed', `optimized keys', and `sorted index pages'.

   * `Auto increment key', `Last value'

     The key number associated the table's `AUTO_INCREMENT' column, and
     the most recently generated value for this column. These fields do
     not appear if there is no such column.

   * `Data records'

     The number of rows in the table.

   * `Deleted blocks'

     How many deleted blocks still have reserved space. You can
     optimize your table to minimize this space. See *Note
     myisam-optimization::.

   * `Datafile parts'

     For dynamic-row format, this indicates how many data blocks there
     are. For an optimized table without fragmented rows, this is the
     same as `Data records'.

   * `Deleted data'

     How many bytes of unreclaimed deleted data there are. You can
     optimize your table to minimize this space. See *Note
     myisam-optimization::.

   * `Datafile pointer'

     The size of the data file pointer, in bytes. It is usually 2, 3,
     4, or 5 bytes. Most tables manage with 2 bytes, but this cannot be
     controlled from MySQL yet. For fixed tables, this is a row
     address. For dynamic tables, this is a byte address.

   * `Keyfile pointer'

     The size of the index file pointer, in bytes. It is usually 1, 2,
     or 3 bytes. Most tables manage with 2 bytes, but this is
     calculated automatically by MySQL. It is always a block address.

   * `Max datafile length'

     How long the table data file can become, in bytes.

   * `Max keyfile length'

     How long the table index file can become, in bytes.

   * `Recordlength'

     How much space each row takes, in bytes.

The `table description' part of the output includes a list of all keys
in the table. For each key, *Note `myisamchk': myisamchk. displays some
low-level information:

   * `Key'

     This key's number. This value is shown only for the first column
     of the key. If this value is missing, the line corresponds to the
     second or later column of a multiple-column key. For the table
     shown in the example, there are two `table description' lines for
     the second index. This indicates that it is a multiple-part index
     with two parts.

   * `Start'

     Where in the row this portion of the index starts.

   * `Len'

     How long this portion of the index is. For packed numbers, this
     should always be the full length of the column. For strings, it
     may be shorter than the full length of the indexed column, because
     you can index a prefix of a string column. The total length of a
     multiple-part key is the sum of the `Len' values for all key parts.

   * `Index'

     Whether a key value can exist multiple times in the index.
     Possible values are `unique' or `multip.' (multiple).

   * `Type'

     What data type this portion of the index has. This is a `MyISAM'
     data type with the possible values `packed', `stripped', or
     `empty'.

   * `Root'

     Address of the root index block.

   * `Blocksize'

     The size of each index block. By default this is 1024, but the
     value may be changed at compile time when MySQL is built from
     source.

   * `Rec/key'

     This is a statistical value used by the optimizer. It tells how
     many rows there are per value for this index. A unique index
     always has a value of 1. This may be updated after a table is
     loaded (or greatly changed) with *Note `myisamchk -a': myisamchk.
     If this is not updated at all, a default value of 30 is given.

The last part of the output provides information about each column:

   * `Field'

     The column number.

   * `Start'

     The byte position of the column within table rows.

   * `Length'

     The length of the column in bytes.

   * `Nullpos', `Nullbit'

     For columns that can be `NULL', `MyISAM' stores `NULL' values as a
     flag in a byte. Depending on how many nullable columns there are,
     there can be one or more bytes used for this purpose. The
     `Nullpos' and `Nullbit' values, if nonempty, indicate which byte
     and bit contains that flag indicating whether the column is `NULL'.

     The position and number of bytes used to store `NULL' flags is
     shown in the line for field 1. This is why there are six `Field'
     lines for the `person' table even though it has only five columns.

   * `Type'

     The data type. The value may contain any of the following
     descriptors:

        * `constant'

          All rows have the same value.

        * `no endspace'

          Do not store endspace.

        * `no endspace, not_always'

          Do not store endspace and do not do endspace compression for
          all values.

        * `no endspace, no empty'

          Do not store endspace. Do not store empty values.

        * `table-lookup'

          The column was converted to an *Note `ENUM': enum.

        * `zerofill(N)'

          The most significant N bytes in the value are always 0 and
          are not stored.

        * `no zeros'

          Do not store zeros.

        * `always zero'

          Zero values are stored using one bit.

   * `Huff tree'

     The number of the Huffman tree associated with the column.

   * `Bits'

     The number of bits used in the Huffman tree.

The `Huff tree' and `Bits' fields are displayed if the table has been
compressed with *Note `myisampack': myisampack. See *Note myisampack::,
for an example of this information.

Example of *Note `myisamchk -eiv': myisamchk. output:

     Checking MyISAM file: person
     Data records:  306688   Deleted blocks:       0
     - check file-size
     - check record delete-chain
     No recordlinks
     - check key delete-chain
     block_size 1024:
     - check index reference
     - check data record references index: 1
     Key:  1:  Keyblocks used:  98%  Packed:    0%  Max levels:  3
     - check data record references index: 2
     Key:  2:  Keyblocks used:  99%  Packed:   97%  Max levels:  3
     - check data record references index: 3
     Key:  3:  Keyblocks used:  98%  Packed:  -14%  Max levels:  3
     Total:    Keyblocks used:  98%  Packed:   89%

     - check records and index references*** LOTS OF ROW NUMBERS DELETED ***

     Records:            306688  M.recordlength:       25  Packed:            83%
     Recordspace used:       97% Empty space:           2% Blocks/Record:   1.00
     Record blocks:      306688  Delete blocks:         0
     Record data:       7934464  Deleted data:          0
     Lost space:         256512  Linkdata:        1156096

     User time 43.08, System time 1.68
     Maximum resident set size 0, Integral resident set size 0
     Non-physical pagefaults 0, Physical pagefaults 0, Swaps 0
     Blocks in 0 out 7, Messages in 0 out 0, Signals 0
     Voluntary context switches 0, Involuntary context switches 0
     Maximum memory usage: 1046926 bytes (1023k)

*Note `myisamchk -eiv': myisamchk. output includes the following
information:

   * `Data records'

     The number of rows in the table.

   * `Deleted blocks'

     How many deleted blocks still have reserved space. You can
     optimize your table to minimize this space. See *Note
     myisam-optimization::.

   * `Key'

     The key number.

   * `Keyblocks used'

     What percentage of the keyblocks are used. When a table has just
     been reorganized with *Note `myisamchk': myisamchk, the values are
     very high (very near theoretical maximum).

   * `Packed'

     MySQL tries to pack key values that have a common suffix.  This
     can only be used for indexes on *Note `CHAR': char. and *Note
     `VARCHAR': char. columns. For long indexed strings that have
     similar leftmost parts, this can significantly reduce the space
     used. In the preceding example, the second key is 40 bytes long
     and a 97% reduction in space is achieved.

   * `Max levels'

     How deep the B-tree for this key is. Large tables with long key
     values get high values.

   * `Records'

     How many rows are in the table.

   * `M.recordlength'

     The average row length. This is the exact row length for tables
     with fixed-length rows, because all rows have the same length.

   * `Packed'

     MySQL strips spaces from the end of strings. The `Packed' value
     indicates the percentage of savings achieved by doing this.

   * `Recordspace used'

     What percentage of the data file is used.

   * `Empty space'

     What percentage of the data file is unused.

   * `Blocks/Record'

     Average number of blocks per row (that is, how many links a
     fragmented row is composed of). This is always 1.0 for
     fixed-format tables. This value should stay as close to 1.0 as
     possible. If it gets too large, you can reorganize the table. See
     *Note myisam-optimization::.

   * `Recordblocks'

     How many blocks (links) are used. For fixed-format tables, this is
     the same as the number of rows.

   * `Deleteblocks'

     How many blocks (links) are deleted.

   * `Recorddata'

     How many bytes in the data file are used.

   * `Deleted data'

     How many bytes in the data file are deleted (unused).

   * `Lost space'

     If a row is updated to a shorter length, some space is lost.  This
     is the sum of all such losses, in bytes.

   * `Linkdata'

     When the dynamic table format is used, row fragments are linked
     with pointers (4 to 7 bytes each).  `Linkdata' is the sum of the
     amount of storage used by all such pointers.


File: manual.info,  Node: myisamchk-memory,  Prev: myisamchk-table-info,  Up: myisamchk

5.6.3.6 `myisamchk' Memory Usage
................................

Memory allocation is important when you run *Note `myisamchk':
myisamchk. *Note `myisamchk': myisamchk. uses no more memory than its
memory-related variables are set to. If you are going to use *Note
`myisamchk': myisamchk. on very large tables, you should first decide
how much memory you want it to use. The default is to use only about
3MB to perform repairs. By using larger values, you can get *Note
`myisamchk': myisamchk. to operate faster. For example, if you have
more than 512MB RAM available, you could use options such as these (in
addition to any other options you might specify):

     shell> myisamchk --sort_buffer_size=256M \
                --key_buffer_size=512M \
                --read_buffer_size=64M \
                --write_buffer_size=64M ...

Using `--sort_buffer_size=16M' is probably enough for most cases.

Be aware that *Note `myisamchk': myisamchk. uses temporary files in
`TMPDIR'. If `TMPDIR' points to a memory file system, out of memory
errors can easily occur. If this happens, run *Note `myisamchk':
myisamchk. with the `--tmpdir=PATH' option to specify a directory
located on a file system that has more space.

When performing repair operations, *Note `myisamchk': myisamchk.  also
needs a lot of disk space:

   * Twice the size of the data file (the original file and a copy).
     This space is not needed if you do a repair with `--quick'; in
     this case, only the index file is re-created. _This space must be
     available on the same file system as the original data file_, as
     the copy is created in the same directory as the original.

   * Space for the new index file that replaces the old one. The old
     index file is truncated at the start of the repair operation, so
     you usually ignore this space. This space must be available on the
     same file system as the original data file.

   * When using `--recover' or `--sort-recover' (but not when using
     `--safe-recover'), you need space on disk for sorting. This space
     is allocated in the temporary directory (specified by `TMPDIR' or
     `--tmpdir=PATH').  The following formula yields the amount of
     space required:

          (LARGEST_KEY + ROW_POINTER_LENGTH) * NUMBER_OF_ROWS * 2

     You can check the length of the keys and the ROW_POINTER_LENGTH
     with *Note `myisamchk -dv TBL_NAME': myisamchk. (see *Note
     myisamchk-table-info::). The ROW_POINTER_LENGTH and NUMBER_OF_ROWS
     values are the `Datafile pointer' and `Data records' values in the
     table description. To determine the LARGEST_KEY value, check the
     `Key' lines in the table description. The `Len' column indicates
     the number of bytes for each key part. For a multiple-column
     index, the key size is the sum of the `Len' values for all key
     parts.

If you have a problem with disk space during repair, you can try
`--safe-recover' instead of `--recover'.


File: manual.info,  Node: myisamlog,  Next: myisampack,  Prev: myisamchk,  Up: programs-admin-utils

5.6.4 `myisamlog' -- Display MyISAM Log File Contents
-----------------------------------------------------

*Note `myisamlog': myisamlog. processes the contents of a `MyISAM' log
file.

Invoke *Note `myisamlog': myisamlog. like this:

     shell> myisamlog [OPTIONS] [LOG_FILE [TBL_NAME] ...]
     shell> isamlog [OPTIONS] [LOG_FILE [TBL_NAME] ...]

The default operation is update (`-u'). If a recovery is done (`-r'),
all writes and possibly updates and deletes are done and errors are
only counted. The default log file name is `myisam.log' for *Note
`myisamlog': myisamlog. and `isam.log' for `isamlog' if no LOG_FILE
argument is given. If tables are named on the command line, only those
tables are updated.

*Note `myisamlog': myisamlog. supports the following options:

   *  `-?', `-I'

     Display a help message and exit.

   * `-c N'

     Execute only N commands.

   *  `-f N'

     Specify the maximum number of open files.

   *  `-i'

     Display extra information before exiting.

   *  `-o OFFSET'

     Specify the starting offset.

   *  `-p N'

     Remove N components from path.

   *  `-r'

     Perform a recovery operation.

   *  `-R RECORD_POS_FILE RECORD_POS'

     Specify record position file and record position.

   *  `-u'

     Perform an update operation.

   *  `-v'

     Verbose mode. Print more output about what the program does.  This
     option can be given multiple times to produce more and more output.

   *  `-w WRITE_FILE'

     Specify the write file.

   *  `-V'

     Display version information.


File: manual.info,  Node: myisampack,  Next: mysqlaccess,  Prev: myisamlog,  Up: programs-admin-utils

5.6.5 `myisampack' -- Generate Compressed, Read-Only MyISAM Tables
------------------------------------------------------------------

The *Note `myisampack': myisampack. utility compresses `MyISAM' tables.
*Note `myisampack': myisampack.  works by compressing each column in
the table separately.  Usually, *Note `myisampack': myisampack. packs
the data file 40% to 70%.

When the table is used later, the server reads into memory the
information needed to decompress columns. This results in much better
performance when accessing individual rows, because you only have to
uncompress exactly one row.

MySQL uses `mmap()' when possible to perform memory mapping on
compressed tables. If `mmap()' does not work, MySQL falls back to
normal read/write file operations.

Please note the following:

   * If the *Note `mysqld': mysqld. server was invoked with external
     locking disabled, it is not a good idea to invoke *Note
     `myisampack': myisampack. if the table might be updated by the
     server during the packing process. It is safest to compress tables
     with the server stopped.

   * After packing a table, it becomes read only. This is generally
     intended (such as when accessing packed tables on a CD).

Invoke *Note `myisampack': myisampack. like this:

     shell> myisampack [OPTIONS] FILE_NAME ...

Each file name argument should be the name of an index (`.MYI') file.
If you are not in the database directory, you should specify the path
name to the file. It is permissible to omit the `.MYI' extension.

After you compress a table with *Note `myisampack': myisampack, you
should use *Note `myisamchk -rq': myisamchk. to rebuild its indexes.
*Note myisamchk::.

*Note `myisampack': myisampack. supports the following options. It also
reads option files and supports the options for processing them
described at *Note option-file-options::.

   *  `--help', `-?'

     Display a help message and exit.

   *  `--backup', `-b'

     Make a backup of each table's data file using the name
     `TBL_NAME.OLD'.

   *  `--character-sets-dir=PATH'

     The directory where character sets are installed. See *Note
     charset-configuration::.

   *  `--debug[=DEBUG_OPTIONS]', `-# [DEBUG_OPTIONS]'

     Write a debugging log. A typical DEBUG_OPTIONS string is
     `'d:t:o,FILE_NAME''.  The default is `'d:t:o''.

   *  `--force', `-f'

     Produce a packed table even if it becomes larger than the original
     or if the intermediate file from an earlier invocation of *Note
     `myisampack': myisampack. exists.  (*Note `myisampack':
     myisampack. creates an intermediate file named `TBL_NAME.TMD' in
     the database directory while it compresses the table. If you kill
     *Note `myisampack': myisampack, the `.TMD' file might not be
     deleted.)  Normally, *Note `myisampack': myisampack. exits with an
     error if it finds that `TBL_NAME.TMD' exists. With `--force',
     *Note `myisampack': myisampack. packs the table anyway.

   *  `--join=BIG_TBL_NAME', `-j BIG_TBL_NAME'

     Join all tables named on the command line into a single packed
     table BIG_TBL_NAME. All tables that are to be combined _must_ have
     identical structure (same column names and types, same indexes,
     and so forth).

     BIG_TBL_NAME must not exist prior to the join operation. All
     source tables named on the command line to be merged into
     BIG_TBL_NAME must exist. The source tables are read for the join
     operation but not modified. The join operation does not create a
     `.frm' file for BIG_TBL_NAME, so after the join operation
     finishes, copy the `.frm' file from one of the source tables and
     name it `BIG_TBL_NAME.frm'.

   *  `--silent', `-s'

     Silent mode. Write output only when errors occur.

   *  `--test', `-t'

     Do not actually pack the table, just test packing it.

   *  `--tmpdir=PATH', `-T PATH'

     Use the named directory as the location where *Note `myisampack':
     myisampack. creates temporary files.

   *  `--verbose', `-v'

     Verbose mode. Write information about the progress of the packing
     operation and its result.

   *  `--version', `-V'

     Display version information and exit.

   *  `--wait', `-w'

     Wait and retry if the table is in use. If the *Note `mysqld':
     mysqld. server was invoked with external locking disabled, it is
     not a good idea to invoke *Note `myisampack': myisampack. if the
     table might be updated by the server during the packing process.

The following sequence of commands illustrates a typical table
compression session:

     shell> ls -l station.*
     -rw-rw-r--   1 monty    my         994128 Apr 17 19:00 station.MYD
     -rw-rw-r--   1 monty    my          53248 Apr 17 19:00 station.MYI
     -rw-rw-r--   1 monty    my           5767 Apr 17 19:00 station.frm

     shell> myisamchk -dvv station

     MyISAM file:     station
     Isam-version:  2
     Creation time: 1996-03-13 10:08:58
     Recover time:  1997-02-02  3:06:43
     Data records:              1192  Deleted blocks:              0
     Datafile parts:            1192  Deleted data:                0
     Datafile pointer (bytes):     2  Keyfile pointer (bytes):     2
     Max datafile length:   54657023  Max keyfile length:   33554431
     Recordlength:               834
     Record format: Fixed length

     table description:
     Key Start Len Index   Type                 Root  Blocksize    Rec/key
     1   2     4   unique  unsigned long        1024       1024          1
     2   32    30  multip. text                10240       1024          1

     Field Start Length Type
     1     1     1
     2     2     4
     3     6     4
     4     10    1
     5     11    20
     6     31    1
     7     32    30
     8     62    35
     9     97    35
     10    132   35
     11    167   4
     12    171   16
     13    187   35
     14    222   4
     15    226   16
     16    242   20
     17    262   20
     18    282   20
     19    302   30
     20    332   4
     21    336   4
     22    340   1
     23    341   8
     24    349   8
     25    357   8
     26    365   2
     27    367   2
     28    369   4
     29    373   4
     30    377   1
     31    378   2
     32    380   8
     33    388   4
     34    392   4
     35    396   4
     36    400   4
     37    404   1
     38    405   4
     39    409   4
     40    413   4
     41    417   4
     42    421   4
     43    425   4
     44    429   20
     45    449   30
     46    479   1
     47    480   1
     48    481   79
     49    560   79
     50    639   79
     51    718   79
     52    797   8
     53    805   1
     54    806   1
     55    807   20
     56    827   4
     57    831   4

     shell> myisampack station.MYI
     Compressing station.MYI: (1192 records)
     - Calculating statistics

     normal:     20  empty-space:   16  empty-zero:     12  empty-fill:  11
     pre-space:   0  end-space:     12  table-lookups:   5  zero:         7
     Original trees:  57  After join: 17
     - Compressing file
     87.14%
     Remember to run myisamchk -rq on compressed tables

     shell> ls -l station.*
     -rw-rw-r--   1 monty    my         127874 Apr 17 19:00 station.MYD
     -rw-rw-r--   1 monty    my          55296 Apr 17 19:04 station.MYI
     -rw-rw-r--   1 monty    my           5767 Apr 17 19:00 station.frm

     shell> myisamchk -dvv station

     MyISAM file:     station
     Isam-version:  2
     Creation time: 1996-03-13 10:08:58
     Recover time:  1997-04-17 19:04:26
     Data records:               1192  Deleted blocks:              0
     Datafile parts:             1192  Deleted data:                0
     Datafile pointer (bytes):      3  Keyfile pointer (bytes):     1
     Max datafile length:    16777215  Max keyfile length:     131071
     Recordlength:                834
     Record format: Compressed

     table description:
     Key Start Len Index   Type                 Root  Blocksize    Rec/key
     1   2     4   unique  unsigned long       10240       1024          1
     2   32    30  multip. text                54272       1024          1

     Field Start Length Type                         Huff tree  Bits
     1     1     1      constant                             1     0
     2     2     4      zerofill(1)                          2     9
     3     6     4      no zeros, zerofill(1)                2     9
     4     10    1                                           3     9
     5     11    20     table-lookup                         4     0
     6     31    1                                           3     9
     7     32    30     no endspace, not_always              5     9
     8     62    35     no endspace, not_always, no empty    6     9
     9     97    35     no empty                             7     9
     10    132   35     no endspace, not_always, no empty    6     9
     11    167   4      zerofill(1)                          2     9
     12    171   16     no endspace, not_always, no empty    5     9
     13    187   35     no endspace, not_always, no empty    6     9
     14    222   4      zerofill(1)                          2     9
     15    226   16     no endspace, not_always, no empty    5     9
     16    242   20     no endspace, not_always              8     9
     17    262   20     no endspace, no empty                8     9
     18    282   20     no endspace, no empty                5     9
     19    302   30     no endspace, no empty                6     9
     20    332   4      always zero                          2     9
     21    336   4      always zero                          2     9
     22    340   1                                           3     9
     23    341   8      table-lookup                         9     0
     24    349   8      table-lookup                        10     0
     25    357   8      always zero                          2     9
     26    365   2                                           2     9
     27    367   2      no zeros, zerofill(1)                2     9
     28    369   4      no zeros, zerofill(1)                2     9
     29    373   4      table-lookup                        11     0
     30    377   1                                           3     9
     31    378   2      no zeros, zerofill(1)                2     9
     32    380   8      no zeros                             2     9
     33    388   4      always zero                          2     9
     34    392   4      table-lookup                        12     0
     35    396   4      no zeros, zerofill(1)               13     9
     36    400   4      no zeros, zerofill(1)                2     9
     37    404   1                                           2     9
     38    405   4      no zeros                             2     9
     39    409   4      always zero                          2     9
     40    413   4      no zeros                             2     9
     41    417   4      always zero                          2     9
     42    421   4      no zeros                             2     9
     43    425   4      always zero                          2     9
     44    429   20     no empty                             3     9
     45    449   30     no empty                             3     9
     46    479   1                                          14     4
     47    480   1                                          14     4
     48    481   79     no endspace, no empty               15     9
     49    560   79     no empty                             2     9
     50    639   79     no empty                             2     9
     51    718   79     no endspace                         16     9
     52    797   8      no empty                             2     9
     53    805   1                                          17     1
     54    806   1                                           3     9
     55    807   20     no empty                             3     9
     56    827   4      no zeros, zerofill(2)                2     9
     57    831   4      no zeros, zerofill(1)                2     9

*Note `myisampack': myisampack. displays the following kinds of
information:

   * `normal'

     The number of columns for which no extra packing is used.

   * `empty-space'

     The number of columns containing values that are only spaces.
     These occupy one bit.

   * `empty-zero'

     The number of columns containing values that are only binary
     zeros. These occupy one bit.

   * `empty-fill'

     The number of integer columns that do not occupy the full byte
     range of their type. These are changed to a smaller type. For
     example, a *Note `BIGINT': numeric-types.  column (eight bytes)
     can be stored as a *Note `TINYINT': numeric-types. column (one
     byte) if all its values are in the range from `-128' to `127'.

   * `pre-space'

     The number of decimal columns that are stored with leading spaces.
     In this case, each value contains a count for the number of
     leading spaces.

   * `end-space'

     The number of columns that have a lot of trailing spaces. In this
     case, each value contains a count for the number of trailing
     spaces.

   * `table-lookup'

     The column had only a small number of different values, which were
     converted to an *Note `ENUM': enum. before Huffman compression.

   * `zero'

     The number of columns for which all values are zero.

   * `Original trees'

     The initial number of Huffman trees.

   * `After join'

     The number of distinct Huffman trees left after joining trees to
     save some header space.

After a table has been compressed, the `Field' lines displayed by *Note
`myisamchk -dvv': myisamchk. include additional information about each
column:

   * `Type'

     The data type. The value may contain any of the following
     descriptors:

        * `constant'

          All rows have the same value.

        * `no endspace'

          Do not store endspace.

        * `no endspace, not_always'

          Do not store endspace and do not do endspace compression for
          all values.

        * `no endspace, no empty'

          Do not store endspace. Do not store empty values.

        * `table-lookup'

          The column was converted to an *Note `ENUM': enum.

        * `zerofill(N)'

          The most significant N bytes in the value are always 0 and
          are not stored.

        * `no zeros'

          Do not store zeros.

        * `always zero'

          Zero values are stored using one bit.

   * `Huff tree'

     The number of the Huffman tree associated with the column.

   * `Bits'

     The number of bits used in the Huffman tree.

After you run *Note `myisampack': myisampack, you must run *Note
`myisamchk': myisamchk. to re-create any indexes. At this time, you can
also sort the index blocks and create statistics needed for the MySQL
optimizer to work more efficiently:

     shell> myisamchk -rq --sort-index --analyze TBL_NAME.MYI

After you have installed the packed table into the MySQL database
directory, you should execute *Note `mysqladmin flush-tables':
mysqladmin. to force *Note `mysqld': mysqld. to start using the new
table.

To unpack a packed table, use the `--unpack' option to *Note
`myisamchk': myisamchk.


File: manual.info,  Node: mysqlaccess,  Next: mysqlbinlog,  Prev: myisampack,  Up: programs-admin-utils

5.6.6 `mysqlaccess' -- Client for Checking Access Privileges
------------------------------------------------------------

*Note `mysqlaccess': mysqlaccess. is a diagnostic tool that Yves
Carlier has provided for the MySQL distribution. It checks the access
privileges for a host name, user name, and database combination. Note
that *Note `mysqlaccess': mysqlaccess. checks access using only the
`user', `db', and `host' tables. It does not check table, column, or
routine privileges specified in the `tables_priv', `columns_priv', or
`procs_priv' tables.

Invoke *Note `mysqlaccess': mysqlaccess. like this:

     shell> mysqlaccess [HOST_NAME [USER_NAME [DB_NAME]]] [OPTIONS]

*Note `mysqlaccess': mysqlaccess. supports the following options.

*`mysqlaccess' Options*

Format      Option File Description                   IntroductionDeprecatedRemoved
-brief      brief       Generate reports in                           
                        single-line tabular format                    
-commit     commit      Copy the new access                           
                        privileges from the                           
                        temporary tables to the                       
                        original grant tables                         
-copy       copy        Reload the temporary grant                    
                        tables from original ones                     
-db=db_name db          Specify the database name                     
-debug=#    debug       Specify the debug level                       
-help                   Display help message and exit                 
-host=host_namehost        Connect to the MySQL server                   
                        on the given host                             
-howto      howto       Display some examples that                    
                        show how to use mysqlaccess                   
-old_server old_server  Assume that the server is an                  
                        old MySQL server (prior to                    
                        MySQL  3.21)                                  
-password[=password]password    The password to use when                      
                        connecting to the server                      
-plan       plan        Display suggestions and                       
                        ideas for future releases                     
-preview    preview     Show the privilege                            
                        differences after making                      
                        changes to the  temporary                     
                        grant tables                                  
-relnotes   relnotes    Display the release notes                     
-rhost=host_namerhost       Connect to the MySQL server                   
                        on the given host                             
-rollback   rollback    Undo the most recent changes                  
                        to the temporary grant                        
                        tables.                                       
-spassword[=password]spassword   The password to use when                      
                        connecting to the server as                   
                        the superuser                                 
-superuser=user_namesuperuser   Specify the user name for                     
                        connecting as the superuser                   
-table      table       Generate reports in table                     
                        format                                        
-user=user_name,user        The MySQL user name to use                    
                        when connecting                               
-version                Display version information                   
                        and exit                                      

   *  `--help', `-?'

     Display a help message and exit.

   *  `--brief', `-b'

     Generate reports in single-line tabular format.

   *  `--commit'

     Copy the new access privileges from the temporary tables to the
     original grant tables. The grant tables must be flushed for the
     new privileges to take effect. (For example, execute a *Note
     `mysqladmin reload': mysqladmin. command.)

   *  `--copy'

     Reload the temporary grant tables from original ones.

   *  `--db=DB_NAME', `-d DB_NAME'

     Specify the database name.

   *  `--debug=N'

     Specify the debug level. N can be an integer from 0 to 3.

   *  `--host=HOST_NAME', `-h HOST_NAME'

     The host name to use in the access privileges.

   *  `--howto'

     Display some examples that show how to use *Note `mysqlaccess':
     mysqlaccess.

   *  `--old_server'

     Assume that the server is an old MySQL server (before MySQL 3.21)
     that does not yet know how to handle full `WHERE' clauses.

   *  `--password[=PASSWORD]', `-p[PASSWORD]'

     The password to use when connecting to the server. If you omit the
     PASSWORD value following the `--password' or `-p' option on the
     command line, *Note `mysqlaccess': mysqlaccess. prompts for one.

     Specifying a password on the command line should be considered
     insecure. See *Note password-security-user::.

   *  `--plan'

     Display suggestions and ideas for future releases.

   *  `--preview'

     Show the privilege differences after making changes to the
     temporary grant tables.

   *  `--relnotes'

     Display the release notes.

   *  `--rhost=HOST_NAME', `-H HOST_NAME'

     Connect to the MySQL server on the given host.

   *  `--rollback'

     Undo the most recent changes to the temporary grant tables.

   *  `--spassword[=PASSWORD]', `-P[PASSWORD]'

     The password to use when connecting to the server as the
     superuser. If you omit the PASSWORD value following the
     `--spassword' or `-p' option on the command line, *Note
     `mysqlaccess': mysqlaccess. prompts for one.

     Specifying a password on the command line should be considered
     insecure. See *Note password-security-user::.

   *  `--superuser=USER_NAME', `-U USER_NAME'

     Specify the user name for connecting as the superuser.

   *  `--table', `-t'

     Generate reports in table format.

   *  `--user=USER_NAME', `-u USER_NAME'

     The user name to use in the access privileges.

   *  `--version', `-v'

     Display version information and exit.

If your MySQL distribution is installed in some nonstandard location,
you must change the location where *Note `mysqlaccess': mysqlaccess.
expects to find the *Note `mysql': mysql. client. Edit the
`mysqlaccess' script at approximately line 18. Search for a line that
looks like this:

     $MYSQL     = '/usr/local/bin/mysql';    # path to mysql executable

Change the path to reflect the location where *Note `mysql': mysql.
actually is stored on your system. If you do not do this, a `Broken
pipe' error will occur when you run *Note `mysqlaccess': mysqlaccess.


File: manual.info,  Node: mysqlbinlog,  Next: mysqldumpslow,  Prev: mysqlaccess,  Up: programs-admin-utils

5.6.7 `mysqlbinlog' -- Utility for Processing Binary Log Files
--------------------------------------------------------------

The server's binary log consists of files containing `events' that
describe modifications to database contents. The server writes these
files in binary format. To display their contents in text format, use
the *Note `mysqlbinlog': mysqlbinlog. utility. You can also use *Note
`mysqlbinlog': mysqlbinlog. to display the contents of relay log files
written by a slave server in a replication setup because relay logs
have the same format as binary logs. The binary log and relay log are
discussed further in *Note binary-log::, and *Note slave-logs::.

Invoke *Note `mysqlbinlog': mysqlbinlog. like this:

     shell> mysqlbinlog [OPTIONS] LOG_FILE ...

For example, to display the contents of the binary log file named
`binlog.000003', use this command:

     shell> mysqlbinlog binlog.0000003

The output includes events contained in `binlog.000003'. Event
information includes the SQL statement, the ID of the server on which
it was executed, the timestamp when the statement was executed, how
much time it took, and so forth.

Events are preceded by header comments that provide additional
information. For example:

     # at 141
     #100309  9:28:36 server id 123  end_log_pos 245
       Query thread_id=3350  exec_time=11  error_code=0

In the first line, the number following `at' indicates the starting
position of the event in the binary log file.

The second line starts with a date and time indicating when the
statement started on the server where the event originated. For
replication, this timestamp is propagated to slave servers.  `server
id' is the `server_id' value of the server where the event originated.
`end_log_pos' indicates where the next event starts (that is, it is the
end position of the current event + 1). `thread_id' indicates which
thread executed the event.  `exec_time' is the time spent executing the
event, on a master server. On a slave, it is the difference of the end
execution time on the slave minus the beginning execution time on the
master. The difference serves as an indicator of how much replication
lags behind the master.  `error_code' indicates the result from
executing the event. Zero means that no error occurred.

The output from *Note `mysqlbinlog': mysqlbinlog. can be re-executed
(for example, by using it as input to *Note `mysql': mysql.) to redo
the statements in the log.  This is useful for recovery operations
after a server crash. For other usage examples, see the discussion
later in this section and in *Note point-in-time-recovery::.

Normally, you use *Note `mysqlbinlog': mysqlbinlog. to read binary log
files directly and apply them to the local MySQL server. It is also
possible to read binary logs from a remote server by using the
`--read-from-remote-server' option. To read remote binary logs, the
connection parameter options can be given to indicate how to connect to
the server.  These options are `--host', `--password', `--port',
`--protocol', `--socket', and `--user'; they are ignored except when
you also use the `--read-from-remote-server' option.

*Note `mysqlbinlog': mysqlbinlog. supports the following options, which
can be specified on the command line or in the `[mysqlbinlog]' and
`[client]' groups of an option file. *Note `mysqlbinlog': mysqlbinlog.
also supports the options for processing option files described at
*Note option-file-options::.

*`mysqlbinlog' Options*

Format      Option File Description                   IntroductionDeprecatedRemoved
-character-sets-dir=pathcharacter-sets-dirThe directory where                           
                        character sets are installed                  
-database=db_namedatabase    List entries for just this                    
                        database                                      
-debug[=debug_options]debug       Write a debugging log                         
-disable-log-bindisable-log-binDisable binary logging                        
-force-read force-read  If mysqlbinlog reads a                        
                        binary log event that it                      
                        does not  recognize, it                       
                        prints a warning                              
-help                   Display help message and exit                 
-hexdump    hexdump     Display a hex dump of the     5.0.16          
                        log in comments                               
-host=host_namehost        Connect to the MySQL server                   
                        on the given host                             
-local-load=pathlocal-load  Prepare local temporary                       
                        files for LOAD DATA INFILE                    
                        in the  specified directory                   
-offset=#   offset      Skip the first N entries in                   
                        the log                                       
-password[=password]password    The password to use when                      
                        connecting to the server                      
-port=port_numport        The TCP/IP port number to                     
                        use for the connection                        
-position=# position    Deprecated. Use                               
                        -start-position                               
-protocol=typeprotocol    The connection protocol to                    
                        use                                           
-read-from-remote-serverread-from-remote-serverRead the binary log from a                    
                        MySQL server rather than                      
                        reading a  local log file                     
-result-file=nameresult-file Direct output to the given                    
                        file                                          
-set-charset=charset_nameset-charset Add a SET NAMES charset_name  5.0.23          
                        statement to the output                       
-short-form short-form  Display only the statements                   
                        contained in the log                          
-socket=pathsocket      For connections to localhost                  
-start-datetime=datetimestart-datetimeStart reading the binary log                  
                        at the first event having a                   
                        timestamp  equal to or later                  
                        than the datetime argument                    
-start-position=#start-positionStart reading the binary log                  
                        at the first event having a                   
                        position  equal to or                         
                        greater than the argument                     
-stop-datetime=datetimestop-datetimeStop reading the binary log                   
                        at the first event having a                   
                        timestamp  equal to or                        
                        greater than the datetime                     
                        argument                                      
-stop-position=#stop-positionStop reading the binary log                   
                        at the first event having a                   
                        position  equal to or                         
                        greater than the argument                     
-to-last-logto-last-log Do not stop at the end of                     
                        the requested binary log                      
                        from a MySQL  server, but                     
                        rather continue printing                      
                        until the end of the last                     
                        binary log                                    
-user=user_name,user        The MySQL user name to use                    
                        when connecting to the server                 
-version                Display version information                   
                        and exit                                      

   *  `--help', `-?'

     Display a help message and exit.

   *  `--character-sets-dir=PATH'

     The directory where character sets are installed. See *Note
     charset-configuration::.

   *  `--database=DB_NAME', `-d DB_NAME'

     This option causes *Note `mysqlbinlog': mysqlbinlog. to output
     entries from the binary log (local log only) that occur while
     DB_NAME is been selected as the default database by *Note `USE':
     use.

     The `--database' option for *Note `mysqlbinlog': mysqlbinlog. is
     similar to the `--binlog-do-db' option for *Note `mysqld': mysqld,
     but can be used to specify only one database. If `--database' is
     given multiple times, only the last instance is used.

     The `--database' option works as follows:

        * While DB_NAME is the default database, statements are output
          whether they modify tables in DB_NAME or a different database.

        * Unless DB_NAME is selected as the default database,
          statements are not output, even if they modify tables in
          DB_NAME.

        * There is an exception for *Note `CREATE DATABASE':
          create-database, *Note `ALTER DATABASE': alter-database, and
          *Note `DROP DATABASE': drop-database. The database being
          _created, altered, or dropped_ is considered to be the
          default database when determining whether to output the
          statement.

     Suppose that the binary log contains these statements:

          INSERT INTO test.t1 (i) VALUES(100);
          INSERT INTO db2.t2 (j)  VALUES(200);
          USE test;
          INSERT INTO test.t1 (i) VALUES(101);
          INSERT INTO t1 (i)      VALUES(102);
          INSERT INTO db2.t2 (j)  VALUES(201);
          USE db2;
          INSERT INTO test.t1 (i) VALUES(103);
          INSERT INTO db2.t2 (j)  VALUES(202);
          INSERT INTO t2 (j)      VALUES(203);

     *Note `mysqlbinlog --database=test': mysqlbinlog. does not output
     the first two *Note `INSERT': insert.  statements because there is
     no default database. It outputs the three *Note `INSERT': insert.
     statements following *Note `USE test': use, but not the three
     *Note `INSERT': insert. statements following *Note `USE db2': use.

     *Note `mysqlbinlog --database=db2': mysqlbinlog. does not output
     the first two *Note `INSERT': insert.  statements because there is
     no default database. It does not output the three *Note `INSERT':
     insert.  statements following *Note `USE test': use, but does
     output the three *Note `INSERT': insert.  statements following
     *Note `USE db2': use.

   *  `--debug[=DEBUG_OPTIONS]', `-# [DEBUG_OPTIONS]'

     Write a debugging log. A typical DEBUG_OPTIONS string is
     `'d:t:o,FILE_NAME''.  The default is
     `'d:t:o,/tmp/mysqlbinlog.trace''.

   *  `--disable-log-bin', `-D'

     Disable binary logging. This is useful for avoiding an endless
     loop if you use the `--to-last-log' option and are sending the
     output to the same MySQL server. This option also is useful when
     restoring after a crash to avoid duplication of the statements you
     have logged.

     This option requires that you have the `SUPER' privilege. It causes
     *Note `mysqlbinlog': mysqlbinlog. to include a `SET sql_log_bin =
     0' statement in its output to disable binary logging of the
     remaining output. The *Note `SET': set-option.  statement is
     ineffective unless you have the `SUPER' privilege.

   *  `--force-read', `-f'

     With this option, if *Note `mysqlbinlog': mysqlbinlog. reads a
     binary log event that it does not recognize, it prints a warning,
     ignores the event, and continues. Without this option, *Note
     `mysqlbinlog': mysqlbinlog. stops if it reads such an event.

   *  `--hexdump', `-H'

     Display a hex dump of the log in comments. The hex output can be
     helpful for replication debugging. Hex dump format is discussed
     later in this section. This option was added in MySQL 5.0.16.

   *  `--host=HOST_NAME', `-h HOST_NAME'

     Get the binary log from the MySQL server on the given host.

   *  `--local-load=PATH', `-l PATH'

     Prepare local temporary files for *Note `LOAD DATA INFILE':
     load-data. in the specified directory.

     *Important*:

     These temporary files are not automatically removed by *Note
     `mysqlbinlog': mysqlbinlog. or any other MySQL program.

   *  `--offset=N', `-o N'

     Skip the first N entries in the log.

   *  `--password[=PASSWORD]', `-p[PASSWORD]'

     The password to use when connecting to the server. If you use the
     short option form (`-p'), you _cannot_ have a space between the
     option and the password. If you omit the PASSWORD value following
     the `--password' or `-p' option on the command line, *Note
     `mysqlbinlog': mysqlbinlog. prompts for one.

     Specifying a password on the command line should be considered
     insecure. See *Note password-security-user::. You can use an
     option file to avoid giving the password on the command line.

   *  `--port=PORT_NUM', `-P PORT_NUM'

     The TCP/IP port number to use for connecting to a remote server.

   *  `--position=N'

     Deprecated. Use `--start-position' instead. `--position' is
     removed in MySQL 5.5.

   *  `--protocol={TCP|SOCKET|PIPE|MEMORY}'

     The connection protocol to use for connecting to the server.  It
     is useful when the other connection parameters normally would
     cause a protocol to be used other than the one you want. For
     details on the permissible values, see *Note connecting::.

   *  `--read-from-remote-server', `-R'

     Read the binary log from a MySQL server rather than reading a
     local log file. Any connection parameter options are ignored
     unless this option is given as well. These options are `--host',
     `--password', `--port', `--protocol', `--socket', and `--user'.

     This option requires that the remote server be running. It works
     only for binary log files on the remote server, not relay log
     files.

   *  `--result-file=NAME', `-r NAME'

     Direct output to the given file.

   *  `--set-charset=CHARSET_NAME'

     Add a `SET NAMES CHARSET_NAME' statement to the output to specify
     the character set to be used for processing log files. This option
     was added in MySQL 5.0.23.

   *  `--short-form', `-s'

     Display only the statements contained in the log, without any
     extra information. This is for testing only, and should not be
     used in production systems.

   *  `--socket=PATH', `-S PATH'

     For connections to `localhost', the Unix socket file to use, or,
     on Windows, the name of the named pipe to use.

   *  `--start-datetime=DATETIME'

     Start reading the binary log at the first event having a timestamp
     equal to or later than the DATETIME argument. The DATETIME value
     is relative to the local time zone on the machine where you run
     *Note `mysqlbinlog': mysqlbinlog. The value should be in a format
     accepted for the *Note `DATETIME': datetime. or *Note `TIMESTAMP':
     datetime. data types. For example:

          shell> mysqlbinlog --start-datetime="2005-12-25 11:25:56" binlog.000003

     This option is useful for point-in-time recovery. See *Note
     backup-strategy-example::.

   *  `--start-position=N', `-j N'

     Start reading the binary log at the first event having a position
     equal to or greater than N. This option applies to the first log
     file named on the command line.

     This option is useful for point-in-time recovery. See *Note
     backup-strategy-example::.

   *  `--stop-datetime=DATETIME'

     Stop reading the binary log at the first event having a timestamp
     equal to or later than the DATETIME argument. This option is
     useful for point-in-time recovery. See the description of the
     `--start-datetime' option for information about the DATETIME value.

     This option is useful for point-in-time recovery. See *Note
     backup-strategy-example::.

   *  `--stop-position=N'

     Stop reading the binary log at the first event having a position
     equal to or greater than N. This option applies to the last log
     file named on the command line.

     This option is useful for point-in-time recovery. See *Note
     backup-strategy-example::.

   *  `--to-last-log', `-t'

     Do not stop at the end of the requested binary log from a MySQL
     server, but rather continue printing until the end of the last
     binary log. If you send the output to the same MySQL server, this
     may lead to an endless loop. This option requires
     `--read-from-remote-server'.

   *  `--user=USER_NAME', `-u USER_NAME'

     The MySQL user name to use when connecting to a remote server.

   *  `--version', `-V'

     Display version information and exit.

You can also set the following variable by using `--VAR_NAME=VALUE'
syntax:

   *  `open_files_limit'

     Specify the number of open file descriptors to reserve.

It is also possible to set variables by using
`--set-variable=VAR_NAME=VALUE' or `-O VAR_NAME=VALUE' syntax. _This
syntax is deprecated_.

You can pipe the output of *Note `mysqlbinlog': mysqlbinlog. into the
*Note `mysql': mysql. client to execute the events contained in the
binary log. This technique is used to recover from a crash when you
have an old backup (see *Note point-in-time-recovery::). For example:

     shell> mysqlbinlog binlog.000001 | mysql -u root -p

Or:

     shell> mysqlbinlog binlog.[0-9]* | mysql -u root -p

You can also redirect the output of *Note `mysqlbinlog': mysqlbinlog.
to a text file instead, if you need to modify the statement log first
(for example, to remove statements that you do not want to execute for
some reason).  After editing the file, execute the statements that it
contains by using it as input to the *Note `mysql': mysql. program:

     shell> mysqlbinlog binlog.000001 > tmpfile
     shell> ... EDIT TMPFILE ...
     shell> mysql -u root -p < tmpfile

When *Note `mysqlbinlog': mysqlbinlog. is invoked with the
`--start-position' option, it displays only those events with an offset
in the binary log greater than or equal to a given position (the given
position must match the start of one event). It also has options to stop
and start when it sees an event with a given date and time. This
enables you to perform point-in-time recovery using the
`--stop-datetime' option (to be able to say, for example, `roll forward
my databases to how they were today at 10:30 a.m.').

If you have more than one binary log to execute on the MySQL server,
the safe method is to process them all using a single connection to the
server. Here is an example that demonstrates what may be _unsafe_:

     shell> mysqlbinlog binlog.000001 | mysql -u root -p # DANGER!!
     shell> mysqlbinlog binlog.000002 | mysql -u root -p # DANGER!!

Processing binary logs this way using multiple connections to the
server causes problems if the first log file contains a *Note `CREATE
TEMPORARY TABLE': create-table. statement and the second log contains a
statement that uses the temporary table. When the first *Note `mysql':
mysql. process terminates, the server drops the temporary table. When
the second *Note `mysql': mysql.  process attempts to use the table,
the server reports `unknown table.'

To avoid problems like this, use a _single_ *Note `mysql': mysql.
process to execute the contents of all binary logs that you want to
process. Here is one way to do so:

     shell> mysqlbinlog binlog.000001 binlog.000002 | mysql -u root -p

Another approach is to write all the logs to a single file and then
process the file:

     shell> mysqlbinlog binlog.000001 >  /tmp/statements.sql
     shell> mysqlbinlog binlog.000002 >> /tmp/statements.sql
     shell> mysql -u root -p -e "source /tmp/statements.sql"

*Note `mysqlbinlog': mysqlbinlog. can produce output that reproduces a
*Note `LOAD DATA INFILE': load-data. operation without the original
data file.  *Note `mysqlbinlog': mysqlbinlog. copies the data to a
temporary file and writes a *Note `LOAD DATA LOCAL INFILE': load-data.
statement that refers to the file. The default location of the
directory where these files are written is system-specific. To specify
a directory explicitly, use the `--local-load' option.

Because *Note `mysqlbinlog': mysqlbinlog. converts *Note `LOAD DATA
INFILE': load-data. statements to *Note `LOAD DATA LOCAL INFILE':
load-data. statements (that is, it adds `LOCAL'), both the client and
the server that you use to process the statements must be configured
with the `LOCAL' capability enabled. See *Note load-data-local::.

*Warning*:

The temporary files created for *Note `LOAD DATA LOCAL': load-data.
statements are _not_ automatically deleted because they are needed
until you actually execute those statements. You should delete the
temporary files yourself after you no longer need the statement log.
The files can be found in the temporary file directory and have names
like ORIGINAL_FILE_NAME-#-#.

The `--hexdump' option produces a hex dump of the log contents:

     shell> mysqlbinlog --hexdump master-bin.000001

The hex output consists of comment lines beginning with `#', so the
output might look like this for the preceding command:

     /*!40019 SET @@session.max_insert_delayed_threads=0*/;
     /*!50003 SET @OLD_COMPLETION_TYPE=@@COMPLETION_TYPE,COMPLETION_TYPE=0*/;
     # at 4
     #051024 17:24:13 server id 1  end_log_pos 98
     # Position  Timestamp   Type   Master ID        Size      Master Pos    Flags
     # 00000004 9d fc 5c 43   0f   01 00 00 00   5e 00 00 00   62 00 00 00   00 00
     # 00000017 04 00 35 2e 30 2e 31 35  2d 64 65 62 75 67 2d 6c |..5.0.15.debug.l|
     # 00000027 6f 67 00 00 00 00 00 00  00 00 00 00 00 00 00 00 |og..............|
     # 00000037 00 00 00 00 00 00 00 00  00 00 00 00 00 00 00 00 |................|
     # 00000047 00 00 00 00 9d fc 5c 43  13 38 0d 00 08 00 12 00 |.......C.8......|
     # 00000057 04 04 04 04 12 00 00 4b  00 04 1a                |.......K...|
     #       Start: binlog v 4, server v 5.0.15-debug-log created 051024 17:24:13
     #       at startup
     ROLLBACK;

Hex dump output currently contains the following elements. This format
is subject to change.

   * `Position': The byte position within the log file.

   * `Timestamp': The event timestamp. In the example shown, `'9d fc 5c
     43'' is the representation of `'051024 17:24:13'' in hexadecimal.

   * `Type': The event type code. In the example shown, `'0f''
     indicates a `FORMAT_DESCRIPTION_EVENT'. The following table lists
     the possible type codes.

     Type                               Name          Meaning
     `00'                               `UNKNOWN_EVENT'This event should never be present in the log.
     `01'                               `START_EVENT_V3'This indicates the start of a log file written by
                                                      MySQL 4 or earlier.
     `02'                               `QUERY_EVENT' The most common type of events. These contain
                                                      statements executed on the master.
     `03'                               `STOP_EVENT'  Indicates that master has stopped.
     `04'                               `ROTATE_EVENT'Written when the master switches to a new log
                                                      file.
     `05'                               `INTVAR_EVENT'Used for `AUTO_INCREMENT' values or when the
                                                      `LAST_INSERT_ID()' function is used in the
                                                      statement.
     `06'                               `LOAD_EVENT'  Used for *Note `LOAD DATA INFILE': load-data. in
                                                      MySQL 3.23.
     `07'                               `SLAVE_EVENT' Reserved for future use.
     `08'                               `CREATE_FILE_EVENT'Used for *Note `LOAD DATA INFILE': load-data.
                                                      statements. This indicates the start of execution
                                                      of such a statement. A temporary file is created
                                                      on the slave. Used in MySQL 4 only.
     `09'                               `APPEND_BLOCK_EVENT'Contains data for use in a *Note `LOAD DATA
                                                      INFILE': load-data. statement. The data is stored
                                                      in the temporary file on the slave.
     `0a'                               `EXEC_LOAD_EVENT'Used for *Note `LOAD DATA INFILE': load-data.
                                                      statements. The contents of the temporary file is
                                                      stored in the table on the slave.  Used in MySQL
                                                      4 only.
     `0b'                               `DELETE_FILE_EVENT'Rollback of a *Note `LOAD DATA INFILE':
                                                      load-data. statement. The temporary file should
                                                      be deleted on the slave.
     `0c'                               `NEW_LOAD_EVENT'Used for *Note `LOAD DATA INFILE': load-data. in
                                                      MySQL 4 and earlier.
     `0d'                               `RAND_EVENT'  Used to send information about random values if
                                                      the `RAND()' function is used in the statement.
     `0e'                               `USER_VAR_EVENT'Used to replicate user variables.
     `0f'                               `FORMAT_DESCRIPTION_EVENT'This indicates the start of a log file written by
                                                      MySQL 5 or later.
     `10'                               `XID_EVENT'   Event indicating commit of an XA transaction.
     `11'                               `BEGIN_LOAD_QUERY_EVENT'Used for *Note `LOAD DATA INFILE': load-data.
                                                      statements in MySQL 5 and later.
     `12'                               `EXECUTE_LOAD_QUERY_EVENT'Used for *Note `LOAD DATA INFILE': load-data.
                                                      statements in MySQL 5 and later.
     `13'                               `TABLE_MAP_EVENT'Reserved for future use.
     `14'                               `WRITE_ROWS_EVENT'Reserved for future use.
     `15'                               `UPDATE_ROWS_EVENT'Reserved for future use.
     `16'                               `DELETE_ROWS_EVENT'Reserved for future use.

   * `Master ID': The server ID of the master that created the event.

   * `Size': The size in bytes of the event.

   * `Master Pos': The position of the next event in the original
     master log file.

   * `Flags': 16 flags. Currently, the following flags are used. The
     others are reserved for future use.

     Flag                               Name          Meaning
     `01'                               `LOG_EVENT_BINLOG_IN_USE_F'Log file correctly closed. (Used only in
                                                      `FORMAT_DESCRIPTION_EVENT'.) If this flag is set
                                                      (if the flags are, for example, `'01 00'') in a
                                                      `FORMAT_DESCRIPTION_EVENT', the log file has not
                                                      been properly closed. Most probably this is
                                                      because of a master crash (for example, due to
                                                      power failure).
     `02'                                             Reserved for future use.
     `04'                               `LOG_EVENT_THREAD_SPECIFIC_F'Set if the event is dependent on the connection
                                                      it was executed in (for example, `'04 00''), for
                                                      example, if the event uses temporary tables.
     `08'                               `LOG_EVENT_SUPPRESS_USE_F'Set in some circumstances when the event is not
                                                      dependent on the default database.


File: manual.info,  Node: mysqldumpslow,  Next: mysqlhotcopy,  Prev: mysqlbinlog,  Up: programs-admin-utils

5.6.8 `mysqldumpslow' -- Summarize Slow Query Log Files
-------------------------------------------------------

The MySQL slow query log contains information about queries that take a
long time to execute (see *Note slow-query-log::).  *Note
`mysqldumpslow': mysqldumpslow. parses MySQL slow query log files and
prints a summary of their contents.

Normally, *Note `mysqldumpslow': mysqldumpslow. groups queries that are
similar except for the particular values of number and string data
values. It `abstracts' these values to `N' and `'S'' when displaying
summary output. The `-a' and `-n' options can be used to modify value
abstracting behavior.

Invoke *Note `mysqldumpslow': mysqldumpslow. like this:

     shell> mysqldumpslow [OPTIONS] [LOG_FILE ...]

*Note `mysqldumpslow': mysqldumpslow. supports the following options.

*`mysqldumpslow' Options*

Format      Option File Description                   IntroductionDeprecatedRemoved
-a                      Do not abstract all numbers                   
                        to N and strings to S                         
-n num                  Abstract numbers with at                      
                        least the specified digits                    
-debug      debug       Write debugging information                   
-g pattern              Only consider statements                      
                        that match the pattern                        
-help                   Display help message and exit                 
-h name                 Host name of the server in                    
                        the log file name                             
-i name                 Name of the server instance                   
-l                      Do not subtract lock time                     
                        from total time                               
-r                      Reverse the sort order                        
-s value                How to sort output                            
-t num                  Display only first num                        
                        queries                                       
-verbose    verbose     Verbose mode                                  

   *  `--help'

     Display a help message and exit.

   *  `-a'

     Do not abstract all numbers to `N' and strings to `'S''.

   *  `--debug', `-d'

     Run in debug mode.

   *  `-g PATTERN'

     Consider only queries that match the (`grep'-style) pattern.

   *  `-h HOST_NAME'

     Host name of MySQL server for `*-slow.log' file name. The value can
     contain a wildcard. The default is `*' (match all).

   *  `-i NAME'

     Name of server instance (if using *Note `mysql.server':
     mysql-server. startup script).

   *  `-l'

     Do not subtract lock time from total time.

   *  `-n N'

     Abstract numbers with at least N digits within names.

   *  `-r'

     Reverse the sort order.

   *  `-s SORT_TYPE'

     How to sort the output. The value of SORT_TYPE should be chosen
     from the following list:

        * `t', `at': Sort by query time or average query time

        * `l', `al': Sort by lock time or average lock time

        * `r', `ar': Sort by rows sent or average rows sent

        * `c': Sort by count

     By default, *Note `mysqldumpslow': mysqldumpslow. sorts by average
     query time (equivalent to `-s at').

   *  `-t N'

     Display only the first N queries in the output.

   *  `--verbose', `-v'

     Verbose mode. Print more information about what the program does.

Example of usage:

     shell> mysqldumpslow

     Reading mysql slow query log from /usr/local/mysql/data/mysqld51-apple-slow.log
     Count: 1  Time=4.32s (4s)  Lock=0.00s (0s)  Rows=0.0 (0), root[root]@localhost
      insert into t2 select * from t1

     Count: 3  Time=2.53s (7s)  Lock=0.00s (0s)  Rows=0.0 (0), root[root]@localhost
      insert into t2 select * from t1 limit N

     Count: 3  Time=2.13s (6s)  Lock=0.00s (0s)  Rows=0.0 (0), root[root]@localhost
      insert into t1 select * from t1


File: manual.info,  Node: mysqlhotcopy,  Next: instance-manager,  Prev: mysqldumpslow,  Up: programs-admin-utils

5.6.9 `mysqlhotcopy' -- A Database Backup Program
-------------------------------------------------

*Note `mysqlhotcopy': mysqlhotcopy. is a Perl script that was
originally written and contributed by Tim Bunce. It uses *Note `FLUSH
TABLES': flush, *Note `LOCK TABLES': lock-tables, and `cp' or `scp' to
make a database backup. It is a fast way to make a backup of the
database or single tables, but it can be run only on the same machine
where the database directories are located.  *Note `mysqlhotcopy':
mysqlhotcopy. works only for backing up `MyISAM' and `ARCHIVE' tables.
It runs on Unix and NetWare.

To use *Note `mysqlhotcopy': mysqlhotcopy, you must have read access to
the files for the tables that you are backing up, the `SELECT'
privilege for those tables, the `RELOAD' privilege (to be able to
execute *Note `FLUSH TABLES': flush.), and the `LOCK TABLES' privilege
(to be able to lock the tables).

     shell> mysqlhotcopy DB_NAME [/PATH/TO/NEW_DIRECTORY]

     shell> mysqlhotcopy DB_NAME_1 ... DB_NAME_N /PATH/TO/NEW_DIRECTORY

Back up tables in the given database that match a regular expression:

     shell> mysqlhotcopy DB_NAME./REGEX/

The regular expression for the table name can be negated by prefixing
it with a tilde (``~''):

     shell> mysqlhotcopy DB_NAME./~REGEX/

*Note `mysqlhotcopy': mysqlhotcopy. supports the following options,
which can be specified on the command line or in the `[mysqlhotcopy]'
and `[client]' groups of an option file. For information about option
files, see *Note option-files::.

*`mysqlhotcopy' Options*

Format      Option File Description                   IntroductionDeprecatedRemoved
-addtodest  addtodest   Do not rename target                          
                        directory (if it exists);                     
                        merely add files to  it                       
-allowold   allowold    Do not abort if a target                      
                        exists; rename it by adding                   
                        an _old  suffix                               
-checkpoint=db_name.tbl_namecheckpoint  Insert checkpoint entries                     
-chroot=pathchroot      Base directory of the chroot                  
                        jail in which mysqld operates                 
-debug      debug       Write a debugging log                         
-dryrun     dryrun      Report actions without                        
                        performing them                               
-flushlog   flushlog    Flush logs after all tables                   
                        are locked                                    
-help                   Display help message and exit                 
-host=host_namehost        Connect to the MySQL server                   
                        on the given host                             
-keepold    keepold     Do not delete previous                        
                        (renamed) target when done                    
-noindices  noindices   Do not include full index                     
                        files in the backup                           
-password[=password]password    The password to use when                      
                        connecting to the server                      
-port=port_numport        The TCP/IP port number to                     
                        use for the connection                        
-quiet      quiet       Be silent except for errors                   
-regexp     regexp      Copy all databases with                       
                        names that match the given                    
                        regular  expression                           
-resetmasterresetmaster Reset the binary log after                    
                        locking all the tables                        
-resetslave resetslave  Reset the master.info file                    
                        after locking all the tables                  
-socket=pathsocket      For connections to localhost                  
-tmpdir=pathtmpdir      The temporary directory                       
-user=user_name,user        The MySQL user name to use                    
                        when connecting to the server                 

   *  `--help', `-?'

     Display a help message and exit.

   *  `--addtodest'

     Do not rename target directory (if it exists); merely add files to
     it.

   *  `--allowold'

     Do not abort if a target exists; rename it by adding an `_old'
     suffix.

   *  `--checkpoint=DB_NAME.TBL_NAME'

     Insert checkpoint entries into the specified database DB_NAME and
     table TBL_NAME.

   *  `--chroot=PATH'

     Base directory of the `chroot' jail in which *Note `mysqld':
     mysqld. operates. The PATH value should match that of the
     `--chroot' option given to *Note `mysqld': mysqld.

   *  `--debug'

     Enable debug output.

   *  `--dryrun', `-n'

     Report actions without performing them.

   *  `--flushlog'

     Flush logs after all tables are locked.

   *  `--host=HOST_NAME', `-h HOST_NAME'

     The host name of the local host to use for making a TCP/IP
     connection to the local server. By default, the connection is made
     to `localhost' using a Unix socket file.

   *  `--keepold'

     Do not delete previous (renamed) target when done.

   *  `--method=COMMAND'

     The method for copying files (`cp' or `scp'). The default is `cp'.

   *  `--noindices'

     Do not include full index files for *Note `MyISAM':
     myisam-storage-engine. tables in the backup.  This makes the
     backup smaller and faster. The indexes for reloaded tables can be
     reconstructed later with *Note `myisamchk -rq': myisamchk.

   *  `--password=PASSWORD', `-pPASSWORD'

     The password to use when connecting to the server. The password
     value is not optional for this option, unlike for other MySQL
     programs.

     Specifying a password on the command line should be considered
     insecure. See *Note password-security-user::. You can use an
     option file to avoid giving the password on the command line.

   *  `--port=PORT_NUM', `-P PORT_NUM'

     The TCP/IP port number to use when connecting to the local server.

   *  `--quiet', `-q'

     Be silent except for errors.

   *  `--record_log_pos=DB_NAME.TBL_NAME'

     Record master and slave status in the specified database DB_NAME
     and table TBL_NAME.

   *  `--regexp=EXPR'

     Copy all databases with names that match the given regular
     expression.

   *  `--resetmaster'

     Reset the binary log after locking all the tables.

   *  `--resetslave'

     Reset the `master.info' file after locking all the tables.

   *  `--socket=PATH', `-S PATH'

     The Unix socket file to use for connections to `localhost'.

   *  `--suffix=STR'

     The suffix to use for names of copied databases.

   *  `--tmpdir=PATH'

     The temporary directory. The default is `/tmp'.

   *  `--user=USER_NAME', `-u USER_NAME'

     The MySQL user name to use when connecting to the server.

Use `perldoc' for additional *Note `mysqlhotcopy': mysqlhotcopy.
documentation, including information about the structure of the tables
needed for the `--checkpoint' and `--record_log_pos' options:

     shell> perldoc mysqlhotcopy


File: manual.info,  Node: instance-manager,  Next: mysql-convert-table-format,  Prev: mysqlhotcopy,  Up: programs-admin-utils

5.6.10 `mysqlmanager' -- The MySQL Instance Manager
---------------------------------------------------

* Menu:

* instance-manager-command-options::  MySQL Instance Manager Command Options
* instance-manager-configuration-files::  MySQL Instance Manager Configuration Files
* instance-manager-startup-process::  Starting the MySQL Server with MySQL Instance Manager
* instance-manager-security-passwords::  Instance Manager User and Password Management
* instance-manager-security-monitoring::  MySQL Server Instance Status Monitoring
* instance-manager-security::    Connecting to MySQL Instance Manager
* instance-manager-commands::    MySQL Instance Manager Commands

*Important*:

MySQL Instance Manager is been deprecated in MySQL 5.1 and is removed
in MySQL 5.5.

`mysqlmanager' is the MySQL Instance Manager (IM). This program
monitors and manages MySQL Database Server instances. MySQL Instance
Manager is available for Unix-like operating systems, and also on
Windows as of MySQL 5.0.13. It runs as a daemon that listens on a
TCP/IP port. On Unix, it also listens on a Unix socket file.

MySQL Instance Manager is included in MySQL distributions from version
5.0.3, and can be used in place of the `mysqld_safe' script to start
and stop one or more instances of MySQL Server. Because Instance
Manager can manage multiple server instances, it can also be used in
place of the *Note `mysqld_multi': mysqld-multi. script. Instance
Manager offers these capabilities:

   * Instance Manager can start and stop instances, and report on the
     status of instances.

   * Server instances can be treated as guarded or unguarded:

        * When Instance Manager starts, it starts each guarded
          instance. If the instance crashes, Instance Manager detects
          this and restarts it. When Instance Manager stops, it stops
          the instance.

        * A nonguarded instance is not started when Instance Manager
          starts or monitored by it. If the instance crashes after
          being started, Instance Manager does not restart it. When
          Instance Manager exits, it does not stop the instance if it
          is running.

     Instances are guarded by default. An instance can be designated as
     nonguarded by including the `nonguarded' option in the
     configuration file.

   * Instance Manager provides an interactive interface for configuring
     instances, so that the need to edit the configuration file
     manually is reduced or eliminated.

   * Instance Manager provides remote instance management. That is, it
     runs on the host where you want to control MySQL Server instances,
     but you can connect to it from a remote host to perform
     instance-management operations.

The following sections describe MySQL Instance Manager operation in
more detail.


File: manual.info,  Node: instance-manager-command-options,  Next: instance-manager-configuration-files,  Prev: instance-manager,  Up: instance-manager

5.6.10.1 MySQL Instance Manager Command Options
...............................................

*Important*:

MySQL Instance Manager is been deprecated in MySQL 5.1 and is removed
in MySQL 5.5.

The MySQL Instance Manager supports a number of command options.  For a
brief listing, invoke `mysqlmanager' with the `--help' option. Options
may be given on the command line or in the Instance Manager
configuration file. On Windows, the standard configuration file is
`my.ini' in the directory where Instance Manager is installed. On Unix,
the standard file is `/etc/my.cnf'. To specify a different
configuration file, start Instance Manager with the `--defaults-file'
option.

`mysqlmanager' supports the following options.  It also reads option
files and supports the options for processing them described at *Note
option-file-options::.

   *  `--help', `-?'

     Display a help message and exit.

   *  `--angel-pid-file=FILE_NAME'

     The file in which the angel process records its process ID when
     `mysqlmanager' runs in daemon mode (that is, when the
     `--run-as-service' option is given). The default file name is
     `mysqlmanager.angel.pid'.

     If the `--angel-pid-file' option is not given, the default angel
     PID file has the same name as the PID file except that any PID
     file extension is replaced with an extension of `.angel.pid'. (For
     example, `mysqlmanager.pid' becomes `mysqlmanager.angel.pid'.)

     This option was added in MySQL 5.0.23.

   *  `--bind-address=IP'

     The IP address to bind to.

   *  `--default-mysqld-path=PATH'

     The path name of the MySQL Server binary. This path name is used
     for all server instance sections in the configuration file for
     which no `mysqld-path' option is present. The default value of
     this option is the compiled-in path name, which depends on how the
     MySQL distribution was configured. Example:
     `--default-mysqld-path=/usr/sbin/mysqld'

   *  `--defaults-file=FILE_NAME'

     Read Instance Manager and MySQL Server settings from the given
     file. All configuration changes made by the Instance Manager will
     be written to this file. This must be the first option on the
     command line if it is used, and the file must exist.

     If this option is not given, Instance Manager uses its standard
     configuration file. On Windows, the standard file is `my.ini' in
     the directory where Instance Manager is installed. On Unix, the
     standard file is `/etc/my.cnf'.

   *  `--install'

     On Windows, install Instance Manager as a Windows service.  The
     service name is `MySQL Manager'. This option was added in MySQL
     5.0.11.

   *  `--log=FILE_NAME'

     The path to the Instance Manager log file. This option has no
     effect unless the `--run-as-service' option is also given. If the
     file name specified for the option is a relative name, the log
     file is created under the directory from which Instance Manager is
     started. To ensure that the file is created in a specific
     directory, specify it as a full path name.

     If `--run-as-service' is given without `--log', the log file is
     `mysqlmanager.log' in the data directory.

     If `--run-as-service' is not given, log messages go to the
     standard output. To capture log output, you can redirect Instance
     Manager output to a file:

          mysqlmanager > im.log

   *  `--monitoring-interval=SECONDS'

     The interval in seconds for monitoring server instances. The
     default value is 20 seconds. Instance Manager tries to connect to
     each monitored (guarded) instance using the nonexisting
     `MySQL_Instance_Manager' user account to check whether it is
     available/not hanging. If the result of the connection attempt
     indicates that the instance is unavailable, Instance Manager
     performs several attempts to restart the instance.

     Normally, the `MySQL_Instance_Manager' account does not exist, so
     the connection attempts by Instance Manager cause the monitored
     instance to produce messages in its general query log similar to
     the following:

          Access denied for user 'MySQL_Instance_M'@'localhost' (using password: YES)

     The `nonguarded' option in the appropriate server instance section
     disables monitoring for a particular instance. If the instance
     dies after being started, Instance Manager will not restart it.
     Instance Manager tries to connect to a nonguarded instance only
     when you request the instance's status (for example, with the `SHOW
     INSTANCES' status.

     See *Note instance-manager-security-monitoring::, for more
     information.

   *  `--passwd', `-P'

     Prepare an entry for the password file, print it to the standard
     output, and exit. You can redirect the output from Instance
     Manager to a file to save the entry in the file.  See also *Note
     instance-manager-security-passwords::. This

   *  `--password-file=FILE_NAME'

     The name of the file where the Instance Manager looks for users
     and passwords. On Windows, the default is `mysqlmanager.passwd' in
     the directory where Instance Manager is installed. On Unix, the
     default file is `/etc/mysqlmanager.passwd'. See also *Note
     instance-manager-security-passwords::.

   *  `--pid-file=FILE_NAME'

     The process ID file to use. On Windows, the default file is
     `mysqlmanager.pid' in the directory where Instance Manager is
     installed. On Unix, the default is `mysqlmanager.pid' in the data
     directory.

   *  `--port=PORT_NUM'

     The port number to use when listening for TCP/IP connections from
     clients. The default port number (assigned by IANA) is 2273.

   *  `--print-defaults'

     Print the current defaults and exit. This must be the first option
     on the command line if it is used.

   *  `--remove'

     On Windows, removes Instance Manager as a Windows service.  This
     assumes that Instance Manager has been run with `--install'
     previously.  This option was added in MySQL 5.0.11.

   *  `--run-as-service'

     On Unix, daemonize and start an angel process. The angel process
     monitors Instance Manager and restarts it if it crashes. (The
     angel process itself is simple and unlikely to crash.)

   *  `--socket=PATH'

     On Unix, the socket file to use for incoming connections.  The
     default file is named `/tmp/mysqlmanager.sock'. This option has no
     meaning on Windows.

   *  `--standalone'

     This option is used on Windows to run Instance Manager in
     standalone mode. You should specify it when you start Instance
     Manager from the command line. This option was added in MySQL
     5.0.13.

   *  `--user=USER_NAME'

     On Unix, the user name of the system account to use for starting
     and running `mysqlmanager'. This option generates a warning and
     has no effect unless you start `mysqlmanager' as `root' (so that
     it can change its effective user ID), or as the named user. It is
     recommended that you configure `mysqlmanager' to run using the
     same account used to run the *Note `mysqld': mysqld.  server.
     (`User' in this context refers to a system login account, not a
     MySQL user listed in the grant tables.)

   *  `--version', `-V'

     Display version information and exit.

   *  `--wait-timeout=N'

     The number of seconds to wait for activity on an incoming
     connection before closing it. The default is 28800 seconds (8
     hours).

     This option was added in MySQL 5.0.19. Before that, the timeout is
     30 seconds and cannot be changed.


File: manual.info,  Node: instance-manager-configuration-files,  Next: instance-manager-startup-process,  Prev: instance-manager-command-options,  Up: instance-manager

5.6.10.2 MySQL Instance Manager Configuration Files
...................................................

*Important*:

MySQL Instance Manager is been deprecated in MySQL 5.1 and is removed
in MySQL 5.5.

Instance Manager uses its standard configuration file unless it is
started with a `--defaults-file' option that specifies a different
file. On Windows, the standard file is `my.ini' in the directory where
Instance Manager is installed. On Unix, the standard file is
`/etc/my.cnf'. (Prior to MySQL 5.0.10, the MySQL Instance Manager read
the same configuration files as the MySQL Server, including
`/etc/my.cnf', `~/.my.cnf', and so forth.)

Instance Manager reads options for itself from the `[manager]' section
of the configuration file, and options for server instances from
`[mysqld]' or `[mysqldN]' sections. The `[manager]' section contains any
of the options listed in *Note instance-manager-command-options::,
except for those specified as having to be given as the first option on
the command line. Here is a sample `[manager]' section:

     # MySQL Instance Manager options section
     [manager]
     default-mysqld-path = /usr/local/mysql/libexec/mysqld
     socket=/tmp/manager.sock
     pid-file=/tmp/manager.pid
     password-file = /home/cps/.mysqlmanager.passwd
     monitoring-interval = 2
     port = 1999
     bind-address = 192.168.1.5

Each `[mysqld]' or `[mysqldN]' instance section specifies options given
by Instance Manager to a server instance at startup. These are mainly
common MySQL Server options (see *Note server-options::). In addition, a
`[mysqldN]' section can contain the options in the following list,
which are specific to Instance Manager. These options are interpreted by
Instance Manager itself; it does not pass them to the server when it
attempts to start that server.

*Warning*:

The Instance Manager-specific options must not be used in a `[mysqld]'
section. If a server is started without using Instance Manager, it will
not recognize these options and will fail to start properly.

   * `mysqld-path = PATH'

     The path name of the *Note `mysqld': mysqld. server binary to use
     for the server instance.

   * `nonguarded'

     This option disables Instance Manager monitoring functionality for
     the server instance. By default, an instance is guarded: At
     Instance Manager start time, it starts the instance. It also
     monitors the instance status and attempts to restart it if it
     fails. At Instance Manager exit time, it stops the instance. None
     of these things happen for nonguarded instances.

   * `shutdown-delay = SECONDS'

     The number of seconds Instance Manager should wait for the server
     instance to shut down. The default value is 35 seconds. After the
     delay expires, Instance Manager assumes that the instance is
     hanging and attempts to terminate it.  If you use `InnoDB' with
     large tables, you should increase this value.

Here are some sample instance sections:

     [mysqld1]
     mysqld-path=/usr/local/mysql/libexec/mysqld
     socket=/tmp/mysql.sock
     port=3307
     server_id=1
     skip-stack-trace
     core-file
     skip-bdb
     log-bin
     log-error
     log=mylog
     log-slow-queries

     [mysqld2]
     nonguarded
     port=3308
     server_id=2
     mysqld-path= /home/cps/mysql/trees/mysql-5.0/sql/mysqld
     socket     = /tmp/mysql.sock5
     pid-file   = /tmp/hostname.pid5
     datadir= /home/cps/mysql_data/data_dir1
     language=/home/cps/mysql/trees/mysql-5.0/sql/share/english
     log-bin
     log=/tmp/fordel.log


File: manual.info,  Node: instance-manager-startup-process,  Next: instance-manager-security-passwords,  Prev: instance-manager-configuration-files,  Up: instance-manager

5.6.10.3 Starting the MySQL Server with MySQL Instance Manager
..............................................................

*Important*:

MySQL Instance Manager is been deprecated in MySQL 5.1 and is removed
in MySQL 5.5.

This section discusses how Instance Manager starts server instances
when it starts. However, before you start Instance Manager, you should
set up a password file for it. Otherwise, you will not be able to
connect to Instance Manager to control it after it starts. For details
about creating Instance Manager accounts, see *Note
instance-manager-security-passwords::.

On Unix, the *Note `mysqld': mysqld. MySQL database server normally is
started with the *Note `mysql.server': mysql-server.  script, which
usually resides in the `/etc/init.d/' directory. In MySQL 5.0.3, this
script invokes `mysqlmanager' (the MySQL Instance Manager binary) to
start MySQL. (In prior versions of MySQL the *Note `mysqld_safe':
mysqld-safe. script is used for this purpose.) Starting from MySQL
5.0.4, the behavior of the startup script was changed again to
incorporate both setup schemes. In version 5.0.4, the startup script
uses the old scheme (invoking *Note `mysqld_safe': mysqld-safe.) by
default, but one can set the `use_mysqld_safe' variable in the script to
`0' (zero) to use the MySQL Instance Manager to start a server.

Starting with MySQL 5.0.19, you can use Instance Manager if you modify
the `my.cnf' configuration file by adding `use-manager' to the
`[mysql.server]' section:

     [mysql.server]
     use-manager

When Instance Manager starts, it reads its configuration file if it
exists to find server instance sections and prepare a list of
instances. Instance sections have names of the form `[mysqld]' or
`[mysqldN]', where N is an unsigned integer (for example, `[mysqld1]',
`[mysqld2]', and so forth).

After preparing the list of instances, Instance Manager starts the
guarded instances in the list. If there are no instances, Instance
Manager creates an instance named `mysqld' and attempts to start it
with default (compiled-in) configuration values. This means that the
Instance Manager cannot find the *Note `mysqld': mysqld. program if it
is not installed in the default location.  (*Note
installation-layouts::, describes default locations for components of
MySQL distributions.) If you have installed the MySQL server in a
nonstandard location, you should create the Instance Manager
configuration file.

Instance Manager also stops all guarded server instances when it shuts
down.

The permissible options for `[mysqldN]' server instance sections are
described in *Note instance-manager-configuration-files::. In these
sections, you can use a special `mysqld-path=PATH-TO-MYSQLD-BINARY'
option that is recognized only by Instance Manager. Use this option to
let Instance Manager know where the *Note `mysqld': mysqld. binary
resides. If there are multiple instances, it may also be necessary to
set other options such as `datadir' and `port', to ensure that each
instance has a different data directory and TCP/IP port number. *Note
multiple-servers::, discusses the configuration values that must differ
for each instance when you run multiple instance on the same machine.

*Warning*:

The `[mysqld]' instance section, if it exists, must not contain any
Instance Manager-specific options.

The typical Unix startup/shutdown cycle for a MySQL server with the
MySQL Instance Manager enabled is as follows:

  1. The `/etc/init.d/mysql' script starts MySQL Instance Manager.

  2. Instance Manager starts the guarded server instances and monitors
     them.

  3. If a server instance fails, Instance Manager restarts it.

  4. If Instance Manager is shut down (for example, with the
     `/etc/init.d/mysql stop' command), it shuts down all server
     instances.


File: manual.info,  Node: instance-manager-security-passwords,  Next: instance-manager-security-monitoring,  Prev: instance-manager-startup-process,  Up: instance-manager

5.6.10.4 Instance Manager User and Password Management
......................................................

*Important*:

MySQL Instance Manager is been deprecated in MySQL 5.1 and is removed
in MySQL 5.5.

The Instance Manager stores its user information in a password file. On
Windows, the default is `mysqlmanager.passwd' in the directory where
Instance Manager is installed. On Unix, the default file is
`/etc/mysqlmanager.passwd'. To specify a different location for the
password file, use the `--password-file' option.

If the password file does not exist or contains no password entries,
you cannot connect to the Instance Manager.

*Note*:

Any Instance Manager process that is running to monitor server
instances does not notice changes to the password file. You must stop
it and restart it after making password entry changes.

Entries in the password file have the following format, where the two
fields are the account user name and encrypted password, separated by a
colon:

     petr:*35110DC9B4D8140F5DE667E28C72DD2597B5C848

Instance Manager password encryption is the same as that used by MySQL
Server. It is a one-way operation; no means are provided for decrypting
encrypted passwords.

Instance Manager accounts differ somewhat from MySQL Server accounts:

   * MySQL Server accounts are associated with a host name, user name,
     and password (see *Note user-names::).

   * Instance Manager accounts are associated with a user name and
     password only.

This means that a client can connect to Instance Manager with a given
user name from any host. To limit connections so that clients can
connect only from the local host, start Instance Manager with the
`--bind-address=127.0.0.1' option so that it listens only to the local
network interface.  Remote clients will not be able to connect. Local
clients can connect like this:

     shell> mysql -h 127.0.0.1 -P 2273

To generate a new entry, invoke Instance Manager with the `--passwd'
option and append the output to the `/etc/mysqlmanager.passwd' file.
Here is an example:

     shell> mysqlmanager --passwd >> /etc/mysqlmanager.passwd
     Creating record for new user.
     Enter user name: mike
     Enter password: mikepass
     Re-type password: mikepass

At the prompts, enter the user name and password for the new Instance
Manager user. You must enter the password twice. It does not echo to
the screen, so double entry guards against entering a different
password than you intend (if the two passwords do not match, no entry
is generated).

The preceding command causes the following line to be added to
`/etc/mysqlmanager.passwd':

     mike:*BBF1F551DD9DD96A01E66EC7DDC073911BAD17BA

Use of the `--password'
(http://dev.mysql.com/doc/refman/5.1/en/instance-manager.html#option_mysqlmanager_password)
option fails if `mysqlmanager' is invoked directly from an IBM 5250
terminal. To work around this, use a command like the following from
the command line to generate the password entry:

     shell> mysql -B --skip-column-name \
              -e 'SELECT CONCAT("USER_NAME",":",PASSWORD("PASS_VAL"));'

The output from the command can be used an entry in the
`/etc/mysqlmanager.passwd' file.


File: manual.info,  Node: instance-manager-security-monitoring,  Next: instance-manager-security,  Prev: instance-manager-security-passwords,  Up: instance-manager

5.6.10.5 MySQL Server Instance Status Monitoring
................................................

*Important*:

MySQL Instance Manager is been deprecated in MySQL 5.1 and is removed
in MySQL 5.5.

To monitor the status of each guarded server instance, the MySQL
Instance Manager attempts to connect to the instance at regular
intervals using the `MySQL_Instance_Manager@localhost' user account
with a password of `check_connection'.

You are _not_ required to create this account for MySQL Server; in
fact, it is expected that it will not exist. Instance Manager can tell
that a server is operational if the server accepts the connection
attempt but refuses access for the account by returning a login error.
However, these failed connection attempts are logged by the server to
its general query log (see *Note query-log::).

Instance Manager also attempts a connection to nonguarded server
instances when you use the `SHOW INSTANCES' or `SHOW INSTANCE STATUS'
command. This is the only status monitoring done for nonguarded
instances.

Instance Manager knows if a server instance fails at startup because it
receives a status from the attempt. For an instance that starts but
later crashes, Instance Manager receives a signal because it is the
parent process of the instance.


File: manual.info,  Node: instance-manager-security,  Next: instance-manager-commands,  Prev: instance-manager-security-monitoring,  Up: instance-manager

5.6.10.6 Connecting to MySQL Instance Manager
.............................................

*Important*:

MySQL Instance Manager is been deprecated in MySQL 5.1 and is removed
in MySQL 5.5.

After you set up a password file for the MySQL Instance Manager and
Instance Manager is running, you can connect to it. The MySQL
client/server protocol is used to communicate with the Instance
Manager. For example, you can connect to it using the standard *Note
`mysql': mysql. client program:

     shell> mysql --port=2273 --host=im.example.org --user=mysql --password

Instance Manager supports the version of the MySQL client/server
protocol used by the client tools and libraries distributed with MySQL
4.1 or later, so other programs that use the MySQL C API also can
connect to it.


File: manual.info,  Node: instance-manager-commands,  Prev: instance-manager-security,  Up: instance-manager

5.6.10.7 MySQL Instance Manager Commands
........................................

*Important*:

MySQL Instance Manager is been deprecated in MySQL 5.1 and is removed
in MySQL 5.5.

After you connect to MySQL Instance Manager, you can issue commands.
The following general principles apply to Instance Manager command
execution:

   * Commands that take an instance name fail if the name is not a
     valid instance name.

   * Commands that take an instance name fail if the instance does not
     exist.

   * Instance Manager maintains information about instance
     configuration in an internal (in-memory) cache. Initially, this
     information comes from the configuration file if it exists, but
     some commands change the configuration of an instance. Commands
     that modify the configuration file fail if the file does not exist
     or is not accessible to Instance Manager.

   * On Windows, the standard file is `my.ini' in the directory where
     Instance Manager is installed. On Unix, the standard configuration
     file is `/etc/my.cnf'. To specify a different configuration file,
     start Instance Manager with the `--defaults-file' option.

   * If a `[mysqld]' instance section exists in the configuration file,
     it must not contain any Instance Manager-specific options (see
     *Note instance-manager-configuration-files::).  Therefore, you
     must not add any of these options if you change the configuration
     for an instance named `mysqld'.

The following list describes the commands that Instance Manager
accepts, with examples.

   * `START INSTANCE INSTANCE_NAME'

     This command attempts to start an offline instance. The command is
     asynchronous; it does not wait for the instance to start.

          mysql> START INSTANCE mysqld4;
          Query OK, 0 rows affected (0,00 sec)

   * `STOP INSTANCE INSTANCE_NAME'

     This command attempts to stop an instance. The command is
     synchronous; it waits for the instance to stop.

          mysql> STOP INSTANCE mysqld4;
          Query OK, 0 rows affected (0,00 sec)

   * `SHOW INSTANCES'

     Shows the names and status of all loaded instances.

          mysql> SHOW INSTANCES;
          +---------------+---------+
          | instance_name | status  |
          +---------------+---------+
          | mysqld3       | offline |
          | mysqld4       | online  |
          | mysqld2       | offline |
          +---------------+---------+

   * `SHOW INSTANCE STATUS INSTANCE_NAME'

     Shows status and version information for an instance.

          mysql> SHOW INSTANCE STATUS mysqld3;
          +---------------+--------+---------+
          | instance_name | status | version |
          +---------------+--------+---------+
          | mysqld3       | online | unknown |
          +---------------+--------+---------+

   * `SHOW INSTANCE OPTIONS INSTANCE_NAME'

     Shows the options used by an instance.

          mysql> SHOW INSTANCE OPTIONS mysqld3;
          +---------------+---------------------------------------------------+
          | option_name   | value                                             |
          +---------------+---------------------------------------------------+
          | instance_name | mysqld3                                           |
          | mysqld-path   | /home/cps/mysql/trees/mysql-4.1/sql/mysqld        |
          | port          | 3309                                              |
          | socket        | /tmp/mysql.sock3                                  |
          | pid-file      | hostname.pid3                                     |
          | datadir       | /home/cps/mysql_data/data_dir1/                   |
          | language      | /home/cps/mysql/trees/mysql-4.1/sql/share/english |
          +---------------+---------------------------------------------------+

   * `SHOW INSTANCE_NAME LOG FILES'

     The command lists all log files used by the instance. The result
     set contains the path to the log file and the log file size. If no
     log file path is specified in the instance section of the
     configuration file (for example, `log=/var/mysql.log'), the
     Instance Manager tries to guess its placement. If Instance Manager
     is unable to guess the log file placement you should specify the
     log file location explicitly by using a log option in the
     appropriate instance section of the configuration file.

          mysql> SHOW mysqld LOG FILES;
          +-------------+------------------------------------+----------+
          | Logfile     | Path                               | Filesize |
          +-------------+------------------------------------+----------+
          | ERROR LOG   | /home/cps/var/mysql/owlet.err      | 9186     |
          | GENERAL LOG | /home/cps/var/mysql/owlet.log      | 471503   |
          | SLOW LOG    | /home/cps/var/mysql/owlet-slow.log | 4463     |
          +-------------+------------------------------------+----------+

     Log options are described in *Note server-options::.

   * `SHOW INSTANCE_NAME LOG {ERROR | SLOW | GENERAL}
     SIZE[,OFFSET_FROM_END]'

     This command retrieves a portion of the specified log file.
     Because most users are interested in the latest log messages, the
     SIZE parameter defines the number of bytes to retrieve from the
     end of the log. To retrieve data from the middle of the log file,
     specify the optional OFFSET_FROM_END parameter. The following
     example retrieves 21 bytes of data, starting 23 bytes before the
     end of the log file and ending 2 bytes before the end:

          mysql> SHOW mysqld LOG GENERAL 21, 2;
          +---------------------+
          | Log                 |
          +---------------------+
          | using password: YES |
          +---------------------+

   * `SET INSTANCE_NAME.OPTION_NAME[=OPTION_VALUE]'

     This command edits the specified instance's configuration section
     to change or add instance options. The option is added to the
     section is it is not already present.  Otherwise, the new setting
     replaces the existing one.

          mysql> SET mysqld2.port=3322;
          Query OK, 0 rows affected (0.00 sec)

     Changes made to the configuration file do not take effect until
     the MySQL server is restarted. In addition, these changes are not
     stored in the instance manager's local cache of instance settings
     until a `FLUSH INSTANCES' command is executed.

   * `UNSET INSTANCE_NAME.OPTION_NAME'

     This command removes an option from an instance's configuration
     section.

          mysql> UNSET mysqld2.port;
          Query OK, 0 rows affected (0.00 sec)

     Changes made to the configuration file do not take effect until
     the MySQL server is restarted. In addition, these changes are not
     stored in the instance manager's local cache of instance settings
     until a `FLUSH INSTANCES' command is executed.

   * `FLUSH INSTANCES'

     This command forces Instance Manager reread the configuration file
     and to refresh internal structures. This command should be
     performed after editing the configuration file. The command does
     not restart instances.

          mysql> FLUSH INSTANCES;
          Query OK, 0 rows affected (0.04 sec)

     `FLUSH INSTANCES' is deprecated and will be removed in MySQL 5.2.


File: manual.info,  Node: mysql-convert-table-format,  Next: mysql-explain-log,  Prev: instance-manager,  Up: programs-admin-utils

5.6.11 `mysql_convert_table_format' -- Convert Tables to Use a Given Storage Engine
-----------------------------------------------------------------------------------

*Note `mysql_convert_table_format': mysql-convert-table-format.
converts the tables in a database to use a particular storage engine
(`MyISAM' by default).  *Note `mysql_convert_table_format':
mysql-convert-table-format. is written in Perl and requires that the
`DBI' and `DBD::mysql' Perl modules be installed (see *Note
perl-support::).

Invoke *Note `mysql_convert_table_format': mysql-convert-table-format.
like this:

     shell> mysql_convert_table_format [OPTIONS]DB_NAME

The DB_NAME argument indicates the database containing the tables to be
converted.

*Note `mysql_convert_table_format': mysql-convert-table-format.
supports the options described in the following list.

   *  `--help'

     Display a help message and exit.

   *  `--force'

     Continue even if errors occur.

   *  `--host=HOST_NAME'

     Connect to the MySQL server on the given host.

   *  `--password=PASSWORD'

     The password to use when connecting to the server. Note that the
     password value is not optional for this option, unlike for other
     MySQL programs.

     Specifying a password on the command line should be considered
     insecure. See *Note password-security-user::. You can use an
     option file to avoid giving the password on the command line.

   *  `--port=PORT_NUM'

     The TCP/IP port number to use for the connection.

   *  `--socket=PATH'

     For connections to `localhost', the Unix socket file to use.

   *  `--type=ENGINE_NAME'

     Specify the storage engine that the tables should be converted to
     use. The default is `MyISAM' if this option is not given.

   *  `--user=USER_NAME'

     The MySQL user name to use when connecting to the server.

   *  `--verbose'

     Verbose mode. Print more information about what the program does.

   *  `--version'

     Display version information and exit.


File: manual.info,  Node: mysql-explain-log,  Next: mysql-find-rows,  Prev: mysql-convert-table-format,  Up: programs-admin-utils

5.6.12 `mysql_explain_log' -- Use EXPLAIN on Statements in Query Log
--------------------------------------------------------------------

*Note `mysql_explain_log': mysql-explain-log. reads its standard input
for query log contents. It uses *Note `EXPLAIN': explain. to analyze
*Note `SELECT': select. statements found in the input. *Note `UPDATE':
update. statements are rewritten to *Note `SELECT': select. statements
and also analyzed with *Note `EXPLAIN': explain.  *Note
`mysql_explain_log': mysql-explain-log. then displays a summary of its
results.

The results may assist you in determining which queries result in table
scans and where it would be beneficial to add indexes to your tables.

Invoke *Note `mysql_explain_log': mysql-explain-log. like this, where
LOG_FILE contains all or part of a MySQL query log:

     shell> mysql_explain_log [OPTIONS] < LOG_FILE

*Note `mysql_explain_log': mysql-explain-log. understands the following
options:

   *  `--help', `-?'

     Display a help message and exit.

   *  `--date=YYMMDD', `-d YYMMDD'

     Select entries from the log only for the given date.

   *  `--host=HOST_NAME', `-h HOST_NAME'

     Connect to the MySQL server on the given host.

   *  `--password=PASSWORD', `-p PASSWORD'

     The password to use when connecting to the server.

     Specifying a password on the command line should be considered
     insecure. See *Note password-security-user::.

   *  `--printerror=1', `-e 1'

     Enable error output.

   *  `--socket=PATH', `-S PATH'

     For connections to `localhost', the Unix socket file to use, or,
     on Windows, the name of the named pipe to use.

   *  `--user=USER_NAME', `-u USER_NAME'

     The MySQL user name to use when connecting to the server.


File: manual.info,  Node: mysql-find-rows,  Next: mysql-fix-extensions,  Prev: mysql-explain-log,  Up: programs-admin-utils

5.6.13 `mysql_find_rows' -- Extract SQL Statements from Files
-------------------------------------------------------------

*Note `mysql_find_rows': mysql-find-rows. reads files containing SQL
statements and extracts statements that match a given regular
expression or that contain `USE DB_NAME' or *Note `SET': set-option.
statements. The utility was written for use with update log files (as
used prior to MySQL 5.0) and as such expects statements to be
terminated with semicolon (`;') characters. It may be useful with other
files that contain SQL statements as long as statements are terminated
with semicolons.

Invoke *Note `mysql_find_rows': mysql-find-rows. like this:

     shell> mysql_find_rows [OPTIONS] [FILE_NAME ...]

Each FILE_NAME argument should be the name of file containing SQL
statements. If no file names are given, *Note `mysql_find_rows':
mysql-find-rows. reads the standard input.

Examples:

     mysql_find_rows --regexp=problem_table --rows=20 < update.log
     mysql_find_rows --regexp=problem_table  update-log.1 update-log.2

*Note `mysql_find_rows': mysql-find-rows. supports the following
options:

   *  `--help', `--Information'

     Display a help message and exit.

   *  `--regexp=PATTERN'

     Display queries that match the pattern.

   *  `--rows=N'

     Quit after displaying N queries.

   *  `--skip-use-db'

     Do not include `USE DB_NAME' statements in the output.

   *  `--start_row=N'

     Start output from this row.


File: manual.info,  Node: mysql-fix-extensions,  Next: mysql-setpermission,  Prev: mysql-find-rows,  Up: programs-admin-utils

5.6.14 `mysql_fix_extensions' -- Normalize Table File Name Extensions
---------------------------------------------------------------------

*Note `mysql_fix_extensions': mysql-fix-extensions. converts the
extensions for `MyISAM' (or `ISAM') table files to their canonical
forms. It looks for files with extensions matching any lettercase
variant of `.frm', `.myd', `.myi', `.isd', and `.ism' and renames them
to have extensions of `.frm', `.MYD', `.MYI', `.ISD', and `.ISM',
respectively. This can be useful after transferring the files from a
system with case-insensitive file names (such as Windows) to a system
with case-sensitive file names.

Invoke *Note `mysql_fix_extensions': mysql-fix-extensions. like this,
where DATA_DIR is the path name to the MySQL data directory.

     shell> mysql_fix_extensions DATA_DIR


File: manual.info,  Node: mysql-setpermission,  Next: mysql-tableinfo,  Prev: mysql-fix-extensions,  Up: programs-admin-utils

5.6.15 `mysql_setpermission' -- Interactively Set Permissions in Grant Tables
-----------------------------------------------------------------------------

*Note `mysql_setpermission': mysql-setpermission. is a Perl script that
was originally written and contributed by Luuk de Boer. It
interactively sets permissions in the MySQL grant tables.  *Note
`mysql_setpermission': mysql-setpermission. is written in Perl and
requires that the `DBI' and `DBD::mysql' Perl modules be installed (see
*Note perl-support::).

Invoke *Note `mysql_setpermission': mysql-setpermission. like this:

     shell> mysql_setpermission [OPTIONS]

OPTIONS should be either `--help' to display the help message, or
options that indicate how to connect to the MySQL server. The account
used when you connect determines which permissions you have when
attempting to modify existing permissions in the grant tables.

`mysql_setpermissions' also reads options from the `[client]' and
`[perl]' groups in the `.my.cnf' file in your home directory, if the
file exists.

*Note `mysql_setpermission': mysql-setpermission. supports the following
options:

   *  `--help'

     Display a help message and exit.

   *  `--host=HOST_NAME'

     Connect to the MySQL server on the given host.

   *  `--password=PASSWORD'

     The password to use when connecting to the server. Note that the
     password value is not optional for this option, unlike for other
     MySQL programs.

     Specifying a password on the command line should be considered
     insecure. See *Note password-security-user::. You can use an
     option file to avoid giving the password on the command line.

   *  `--port=PORT_NUM'

     The TCP/IP port number to use for the connection.

   *  `--socket=PATH'

     For connections to `localhost', the Unix socket file to use.

   *  `--user=USER_NAME'

     The MySQL user name to use when connecting to the server.


File: manual.info,  Node: mysql-tableinfo,  Next: mysql-waitpid,  Prev: mysql-setpermission,  Up: programs-admin-utils

5.6.16 `mysql_tableinfo' -- Generate Database Metadata
------------------------------------------------------

*Note `mysql_tableinfo': mysql-tableinfo. creates tables and populates
them with database metadata. It uses *Note `SHOW DATABASES':
show-databases, *Note `SHOW TABLES': show-tables, *Note `SHOW TABLE
STATUS': show-table-status, *Note `SHOW COLUMNS': show-columns, and
*Note `SHOW INDEX': show-index. to obtain the metadata.

In MySQL 5.0 and up, the `INFORMATION_SCHEMA' database contains the
same kind of information in the *Note `SCHEMATA': schemata-table, *Note
`TABLES': tables-table, *Note `COLUMNS': columns-table, and *Note
`STATISTICS': statistics-table. tables. See *Note information-schema::.

Invoke *Note `mysql_tableinfo': mysql-tableinfo. like this:

     shell> mysql_tableinfo [OPTIONS] DB_NAME [DB_LIKE [TBL_LIKE]]

The DB_NAME argument indicates which database *Note `mysql_tableinfo':
mysql-tableinfo. should use as the location for the metadata tables.
The database will be created if it does not exist. The tables will be
named `db', `tbl' (or `tbl_status'), `col', and `idx'.

If the DB_LIKE or TBL_LIKE arguments are given, they are used as
patterns and metadata is generated only for databases or tables that
match the patterns. These arguments default to `%' if not given.

Examples:

     mysql_tableinfo info
     mysql_tableinfo info world
     mysql_tableinfo info mydb tmp%

Each of the commands stores information into tables in the `info'
database. The first stores information for all databases and tables.
The second stores information for all tables in the `world' database.
The third stores information for tables in the `mydb' database that
have names matching the pattern `tmp%'.

*Note `mysql_tableinfo': mysql-tableinfo. supports the following
options:

*`mysql_tableinfo' Options*

Format      Option File Description                   IntroductionDeprecatedRemoved
-clear      clear       Before populating each                        
                        metadata table, drop it if                    
                        it exists                                     
-clear-only clear-only  Similar to -clear, but exits                  
                        after dropping the metadata                   
                        tables  to be populated.                      
-col        col         Generate column metadata                      
                        into the col table                            
-help                   Display help message and exit                 
-host=host_namehost        Connect to the MySQL server                   
                        on the given host                             
-idx        idx         Generate index metadata into                  
                        the idx table                                 
-password=passwordpassword    The password to use when                      
                        connecting to the server -                    
                        not optional                                  
-port=port_numport        The TCP/IP port number to                     
                        use for the connection                        
-prefix=prefix_strprefix      Add prefix_str at the                         
                        beginning of each metadata                    
                        table name                                    
-quiet      quiet       Be silent except for errors                   
-socket=pathsocket      Display version information                   
                        and exit                                      
-tbl-status tbl-status  Use SHOW TABLE STATUS                         
                        instead of SHOW TABLES                        
-user=user_name,user        The mysql_tableinfo user                      
                        name to use when connecting                   
                        to the server                                 

   *  `--help'

     Display a help message and exit.

   *  `--clear'

     Before populating each metadata table, drop it if it exists.

   *  `--clear-only'

     Similar to `--clear', but exits after dropping the metadata tables
     to be populated.

   *  `--col'

     Generate column metadata into the `col' table.

   *  `--host=HOST_NAME', `-h HOST_NAME'

     Connect to the MySQL server on the given host.

   *  `--idx'

     Generate index metadata into the `idx' table.

   *  `--password=PASSWORD', `-pPASSWORD'

     The password to use when connecting to the server. Note that the
     password value is not optional for this option, unlike for other
     MySQL programs. You can use an option file to avoid giving the
     password on the command line.

     Specifying a password on the command line should be considered
     insecure. See *Note password-security-user::.

   *  `--port=PORT_NUM', `-P PORT_NUM'

     The TCP/IP port number to use for the connection.

   *  `--prefix=PREFIX_STR'

     Add PREFIX_STR at the beginning of each metadata table name.

   *  `--quiet', `-q'

     Be silent except for errors.

   *  `--socket=PATH', `-S PATH'

     The Unix socket file to use for the connection.

   *  `--tbl-status'

     Use *Note `SHOW TABLE STATUS': show-table-status. instead of *Note
     `SHOW TABLES': show-tables. This provides more complete
     information, but is slower.

   *  `--user=USER_NAME', `-u USER_NAME'

     The MySQL user name to use when connecting to the server.


File: manual.info,  Node: mysql-waitpid,  Next: mysql-zap,  Prev: mysql-tableinfo,  Up: programs-admin-utils

5.6.17 `mysql_waitpid' -- Kill Process and Wait for Its Termination
-------------------------------------------------------------------

*Note `mysql_waitpid': mysql-waitpid. signals a process to terminate
and waits for the process to exit. It uses the `kill()' system call and
Unix signals, so it runs on Unix and Unix-like systems.

Invoke *Note `mysql_waitpid': mysql-waitpid. like this:

     shell> mysql_waitpid [OPTIONS] PID WAIT_TIME

*Note `mysql_waitpid': mysql-waitpid. sends signal 0 to the process
identified by PID and waits up to WAIT_TIME seconds for the process to
terminate. PID and WAIT_TIME must be positive integers.

If process termination occurs within the wait time or the process does
not exist, *Note `mysql_waitpid': mysql-waitpid. returns 0. Otherwise,
it returns 1.

If the `kill()' system call cannot handle signal 0, `mysql_waitpid()'
uses signal 1 instead.

*Note `mysql_waitpid': mysql-waitpid. supports the following options:

   *  `--help', `-?', `-I'

     Display a help message and exit.

   *  `--verbose', `-v'

     Verbose mode. Display a warning if signal 0 could not be used and
     signal 1 is used instead.

   *  `--version', `-V'

     Display version information and exit.


File: manual.info,  Node: mysql-zap,  Prev: mysql-waitpid,  Up: programs-admin-utils

5.6.18 `mysql_zap' -- Kill Processes That Match a Pattern
---------------------------------------------------------

*Note `mysql_zap': mysql-zap. kills processes that match a pattern. It
uses the `ps' command and Unix signals, so it runs on Unix and
Unix-like systems.

Invoke *Note `mysql_zap': mysql-zap. like this:

     shell> mysql_zap [-SIGNAL] [-?Ift] PATTERN

A process matches if its output line from the `ps' command contains the
pattern. By default, *Note `mysql_zap': mysql-zap. asks for
confirmation for each process. Respond `y' to kill the process, or `q'
to exit *Note `mysql_zap': mysql-zap. For any other response, *Note
`mysql_zap': mysql-zap. does not attempt to kill the process.

If the `-SIGNAL' option is given, it specifies the name or number of
the signal to send to each process. Otherwise, *Note `mysql_zap':
mysql-zap.  tries first with `TERM' (signal 15) and then with *Note
`KILL': kill. (signal 9).

*Note `mysql_zap': mysql-zap. supports the following additional options:

   *  `--help', `-?', `-I'

     Display a help message and exit.

   *  `-f'

     Force mode. *Note `mysql_zap': mysql-zap. attempts to kill each
     process without confirmation.

   *  `-t'

     Test mode. Display information about each process but do not kill
     it.


File: manual.info,  Node: programs-development,  Next: programs-miscellaneous,  Prev: programs-admin-utils,  Up: programs

5.7 MySQL Program Development Utilities
=======================================

* Menu:

* msql2mysql::                   `msql2mysql' --- Convert mSQL Programs for Use with MySQL
* mysql-config::                 `mysql_config' --- Get Compile Options for Compiling Clients
* my-print-defaults::            `my_print_defaults' --- Display Options from Option Files
* resolve-stack-dump::           `resolve_stack_dump' --- Resolve Numeric Stack Trace Dump to Symbols

This section describes some utilities that you may find useful when
developing MySQL programs.

In shell scripts, you can use the *Note `my_print_defaults':
my-print-defaults. program to parse option files and see what options
would be used by a given program. The following example shows the
output that *Note `my_print_defaults': my-print-defaults.  might
produce when asked to show the options found in the `[client]' and
`[mysql]' groups:

     shell> my_print_defaults client mysql
     --port=3306
     --socket=/tmp/mysql.sock
     --no-auto-rehash

Note for developers: Option file handling is implemented in the C
client library simply by processing all options in the appropriate
group or groups before any command-line arguments. This works well for
programs that use the last instance of an option that is specified
multiple times. If you have a C or C++ program that handles multiply
specified options this way but that doesn't read option files, you need
add only two lines to give it that capability. Check the source code of
any of the standard MySQL clients to see how to do this.

Several other language interfaces to MySQL are based on the C client
library, and some of them provide a way to access option file contents.
These include Perl and Python. For details, see the documentation for
your preferred interface.


File: manual.info,  Node: msql2mysql,  Next: mysql-config,  Prev: programs-development,  Up: programs-development

5.7.1 `msql2mysql' -- Convert mSQL Programs for Use with MySQL
--------------------------------------------------------------

Initially, the MySQL C API was developed to be very similar to that for
the mSQL database system. Because of this, mSQL programs often can be
converted relatively easily for use with MySQL by changing the names of
the C API functions.

The *Note `msql2mysql': msql2mysql. utility performs the conversion of
mSQL C API function calls to their MySQL equivalents. *Note
`msql2mysql': msql2mysql. converts the input file in place, so make a
copy of the original before converting it. For example, use *Note
`msql2mysql': msql2mysql. like this:

     shell> cp client-prog.c client-prog.c.orig
     shell> msql2mysql client-prog.c
     client-prog.c converted

Then examine `client-prog.c' and make any post-conversion revisions
that may be necessary.

*Note `msql2mysql': msql2mysql. uses the *Note `replace':
replace-utility. utility to make the function name substitutions. See
*Note replace-utility::.


File: manual.info,  Node: mysql-config,  Next: my-print-defaults,  Prev: msql2mysql,  Up: programs-development

5.7.2 `mysql_config' -- Get Compile Options for Compiling Clients
-----------------------------------------------------------------

*Note `mysql_config': mysql-config. provides you with useful
information for compiling your MySQL client and connecting it to MySQL.

*Note `mysql_config': mysql-config. supports the following options.

   *  `--cflags'

     Compiler flags to find include files and critical compiler flags
     and defines used when compiling the `libmysqlclient' library. The
     options returned are tied to the specific compiler that was used
     when the library was created and might clash with the settings for
     your own compiler. Use `--include' for more portable options that
     contain only include paths.

   *  `--include'

     Compiler options to find MySQL include files.

   *  `--libmysqld-libs', `--embedded'

     Libraries and options required to link with the MySQL embedded
     server.

   *  `--libs'

     Libraries and options required to link with the MySQL client
     library.

   *  `--libs_r'

     Libraries and options required to link with the thread-safe MySQL
     client library.

   *  `--port'

     The default TCP/IP port number, defined when configuring MySQL.

   *  `--socket'

     The default Unix socket file, defined when configuring MySQL.

   *  `--version'

     Version number for the MySQL distribution.

If you invoke *Note `mysql_config': mysql-config. with no options, it
displays a list of all options that it supports, and their values:

     shell> mysql_config
     Usage: /usr/local/mysql/bin/mysql_config [options]
     Options:
       --cflags         [-I/usr/local/mysql/include/mysql -mcpu=pentiumpro]
       --include        [-I/usr/local/mysql/include/mysql]
       --libs           [-L/usr/local/mysql/lib/mysql -lmysqlclient -lz
                         -lcrypt -lnsl -lm -L/usr/lib -lssl -lcrypto]
       --libs_r         [-L/usr/local/mysql/lib/mysql -lmysqlclient_r
                         -lpthread -lz -lcrypt -lnsl -lm -lpthread]
       --socket         [/tmp/mysql.sock]
       --port           [3306]
       --version        [4.0.16]
       --libmysqld-libs [-L/usr/local/mysql/lib/mysql -lmysqld -lpthread -lz
                         -lcrypt -lnsl -lm -lpthread -lrt]

You can use *Note `mysql_config': mysql-config. within a command line
to include the value that it displays for a particular option. For
example, to compile a MySQL client program, use *Note `mysql_config':
mysql-config. as follows:

     shell> CFG=/usr/local/mysql/bin/mysql_config
     shell> sh -c "gcc -o progname `$CFG --include` progname.c `$CFG --libs`"

When you use *Note `mysql_config': mysql-config. this way, be sure to
invoke it within backtick (```'') characters. That tells the shell to
execute it and substitute its output into the surrounding command.


File: manual.info,  Node: my-print-defaults,  Next: resolve-stack-dump,  Prev: mysql-config,  Up: programs-development

5.7.3 `my_print_defaults' -- Display Options from Option Files
--------------------------------------------------------------

*Note `my_print_defaults': my-print-defaults. displays the options that
are present in option groups of option files. The output indicates what
options will be used by programs that read the specified option groups.
For example, the *Note `mysqlcheck': mysqlcheck. program reads the
`[mysqlcheck]' and `[client]' option groups. To see what options are
present in those groups in the standard option files, invoke *Note
`my_print_defaults': my-print-defaults. like this:

     shell> my_print_defaults mysqlcheck client
     --user=myusername
     --password=secret
     --host=localhost

The output consists of options, one per line, in the form that they
would be specified on the command line.

*Note `my_print_defaults': my-print-defaults. supports the following
options.

   *  `--help', `-?'

     Display a help message and exit.

   *  `--config-file=FILE_NAME',

     `--defaults-file=FILE_NAME', `-c FILE_NAME'

     Read only the given option file.

   *  `--debug=DEBUG_OPTIONS', `-# DEBUG_OPTIONS'

     Write a debugging log. A typical DEBUG_OPTIONS string is
     `'d:t:o,FILE_NAME''.  The default is
     `'d:t:o,/tmp/my_print_defaults.trace''.

   *  `--defaults-extra-file=FILE_NAME',

     `--extra-file=FILE_NAME', `-e FILE_NAME'

     Read this option file after the global option file but (on Unix)
     before the user option file.

   *  `--defaults-group-suffix=SUFFIX', `-g SUFFIX'

     In addition to the groups named on the command line, read groups
     that have the given suffix.

   *  `--no-defaults', `-n'

     Return an empty string.

   *  `--verbose', `-v'

     Verbose mode. Print more information about what the program does.

   *  `--version', `-V'

     Display version information and exit.


File: manual.info,  Node: resolve-stack-dump,  Prev: my-print-defaults,  Up: programs-development

5.7.4 `resolve_stack_dump' -- Resolve Numeric Stack Trace Dump to Symbols
-------------------------------------------------------------------------

*Note `resolve_stack_dump': resolve-stack-dump. resolves a numeric stack
dump to symbols.

Invoke *Note `resolve_stack_dump': resolve-stack-dump. like this:

     shell> resolve_stack_dump [OPTIONS] SYMBOLS_FILE [NUMERIC_DUMP_FILE]

The symbols file should include the output from the `nm --numeric-sort
mysqld' command. The numeric dump file should contain a numeric stack
track from *Note `mysqld': mysqld. If no numeric dump file is named on
the command line, the stack trace is read from the standard input.

*Note `resolve_stack_dump': resolve-stack-dump. supports the following
options.

   *  `--help', `-h'

     Display a help message and exit.

   *  `--numeric-dump-file=FILE_NAME', `-n FILE_NAME'

     Read the stack trace from the given file.

   *  `--symbols-file=FILE_NAME', `-s FILE_NAME'

     Use the given symbols file.

   *  `--version', `-V'

     Display version information and exit.


File: manual.info,  Node: programs-miscellaneous,  Prev: programs-development,  Up: programs

5.8 Miscellaneous Programs
==========================

* Menu:

* perror::                       `perror' --- Explain Error Codes
* replace-utility::              `replace' --- A String-Replacement Utility
* resolveip::                    `resolveip' --- Resolve Host name to IP Address or Vice Versa


File: manual.info,  Node: perror,  Next: replace-utility,  Prev: programs-miscellaneous,  Up: programs-miscellaneous

5.8.1 `perror' -- Explain Error Codes
-------------------------------------

For most system errors, MySQL displays, in addition to an internal text
message, the system error code in one of the following styles:

     message ... (errno: #)
     message ... (Errcode: #)

You can find out what the error code means by examining the
documentation for your system or by using the *Note `perror': perror.
utility.

*Note `perror': perror. prints a description for a system error code or
for a storage engine (table handler) error code.

Invoke *Note `perror': perror. like this:

     shell> perror [OPTIONS] ERRORCODE ...

Example:

     shell> perror 13 64
     OS error code  13:  Permission denied
     OS error code  64:  Machine is not on the network

To obtain the error message for a MySQL Cluster error code, invoke
*Note `perror': perror. with the `--ndb' option:

     shell> perror --ndb ERRORCODE

Note that the meaning of system error messages may be dependent on your
operating system. A given error code may mean different things on
different operating systems.

*Note `perror': perror. supports the following options.

   *  `--help', `--info', `-I', `-?'

     Display a help message and exit.

   *  `--ndb'

     Print the error message for a MySQL Cluster error code.

   *  `--silent', `-s'

     Silent mode. Print only the error message.

   *  `--verbose', `-v'

     Verbose mode. Print error code and message. This is the default
     behavior.

   *  `--version', `-V'

     Display version information and exit.


File: manual.info,  Node: replace-utility,  Next: resolveip,  Prev: perror,  Up: programs-miscellaneous

5.8.2 `replace' -- A String-Replacement Utility
-----------------------------------------------

The *Note `replace': replace-utility. utility program changes strings
in place in files or on the standard input.

Invoke *Note `replace': replace-utility. in one of the following ways:

     shell> replace FROM TO [FROM TO] ... -- FILE_NAME [FILE_NAME] ...
     shell> replace FROM TO [FROM TO] ... < FILE_NAME

FROM represents a string to look for and TO represents its replacement.
There can be one or more pairs of strings.

Use the `--' option to indicate where the string-replacement list ends
and the file names begin. In this case, any file named on the command
line is modified in place, so you may want to make a copy of the
original before converting it. REPLACE prints a message indicating
which of the input files it actually modifies.

If the `--' option is not given, *Note `replace': replace-utility.
reads the standard input and writes to the standard output.

*Note `replace': replace-utility. uses a finite state machine to match
longer strings first. It can be used to swap strings. For example, the
following command swaps `a' and `b' in the given files, `file1' and
`file2':

     shell> replace a b b a -- file1 file2 ...

The *Note `replace': replace-utility. program is used by *Note
`msql2mysql': msql2mysql. See *Note msql2mysql::.

*Note `replace': replace-utility. supports the following options.

   *  `-?', `-I'

     Display a help message and exit.

   *  `-#DEBUG_OPTIONS'

     Enable debugging.

   *  `-s'

     Silent mode. Print less information what the program does.

   *  `-v'

     Verbose mode. Print more information about what the program does.

   *  `-V'

     Display version information and exit.


File: manual.info,  Node: resolveip,  Prev: replace-utility,  Up: programs-miscellaneous

5.8.3 `resolveip' -- Resolve Host name to IP Address or Vice Versa
------------------------------------------------------------------

The *Note `resolveip': resolveip. utility resolves host names to IP
addresses and vice versa.

Invoke *Note `resolveip': resolveip. like this:

     shell> resolveip [OPTIONS] {HOST_NAME|IP-ADDR} ...

*Note `resolveip': resolveip. supports the following options.

   *  `--help', `--info', `-?', `-I'

     Display a help message and exit.

   *  `--silent', `-s'

     Silent mode. Produce less output.

   *  `--version', `-V'

     Display version information and exit.


File: manual.info,  Node: server-administration,  Next: backup-and-recovery,  Prev: programs,  Up: Top

6 MySQL Server Administration
*****************************

* Menu:

* mysqld-server::                The MySQL Server
* server-logs::                  MySQL Server Logs
* security::                     General Security Issues
* privilege-system::             The MySQL Access Privilege System
* user-account-management::      MySQL User Account Management
* multiple-servers::             Running Multiple MySQL Instances on One Machine

End of Product Lifecycle

Active development for MySQL Database Server version 5.0 has ended.
Oracle offers various support offerings which may be of interest. For
details and more information, see the MySQL section of the Lifetime
Support Policy for Oracle Technology Products
(http://www.oracle.com/us/support/lifetime-support/index.html). Please
consider upgrading to a recent version.

MySQL Server (*Note `mysqld': mysqld.) is the main program that does
most of the work in a MySQL installation. This section provides an
overview of MySQL Server and covers topics that deal with administering
a MySQL installation:

   * Server configuration

   * The server log files

   * Security issues and user-account management

   * Management of multiple servers on a single machine


File: manual.info,  Node: mysqld-server,  Next: server-logs,  Prev: server-administration,  Up: server-administration

6.1 The MySQL Server
====================

* Menu:

* mysqld-option-tables::         Server Option and Variable Reference
* server-options::               Server Command Options
* server-system-variables::      Server System Variables
* using-system-variables::       Using System Variables
* server-status-variables::      Server Status Variables
* server-sql-mode::              Server SQL Modes
* server-side-help-support::     Server-Side Help
* server-signal-response::       Server Response to Signals
* server-shutdown::              The Shutdown Process

*Note `mysqld': mysqld. is the MySQL server. The following discussion
covers these MySQL server configuration topics:

   * Startup options that the server supports

   * Server system variables

   * Server status variables

   * How to set the server SQL mode

   * The server shutdown process

*Note*:

Not all storage engines are supported by all MySQL server binaries and
configurations. To find out how to determine which storage engines your
MySQL server installation supports, see *Note show-engines::.


File: manual.info,  Node: mysqld-option-tables,  Next: server-options,  Prev: mysqld-server,  Up: mysqld-server

6.1.1 Server Option and Variable Reference
------------------------------------------

The following table provides a list of all the command line options,
server and status variables applicable within `mysqld'.

The table lists command-line options (Cmd-line), options valid in
configuration files (Option file), server system variables (System
Var), and status variables (Status var) in one unified list, with
notification of where each option/variable is valid. If a server option
set on the command line or in an option file differs from the name of
the corresponding server system or status variable, the variable name
is noted immediately below the corresponding option. For status
variables, the scope of the variable is shown (Scope) as either global,
session, or both. Please see the corresponding sections for details on
setting and using the options and variables. Where appropriate, a
direct link to further information on the item as available.

For a version of this table that is specific to MySQL Cluster, see
*Note mysql-cluster-option-tables::.

*Option/Variable Summary*

Name           Cmd-Line    Option file System Var  Status Var  Var Scope   Dynamic
abort-slave-event-countYes         Yes                                             
Aborted_clients                                    Yes         Global      No
Aborted_connects                                    Yes         Global      No
allow-suspicious-udfsYes         Yes                                             
ansi           Yes         Yes                                             
auto_increment_incrementYes         Yes         Yes                     Both        Yes
auto_increment_offsetYes         Yes         Yes                     Both        Yes
autocommit     Yes         Yes         Yes                     Session     Yes
automatic_sp_privileges                        Yes                     Global      Yes
back_log       Yes         Yes         Yes                     Global      No
basedir        Yes         Yes         Yes                     Global      No
bdb_cache_size Yes         Yes         Yes                     Global      No
bdb-home       Yes         Yes                                 Global      No
- _Variable_:                          Yes                     Global      No
bdb_home                                                                   
bdb-lock-detectYes         Yes                                 Global      No
- _Variable_:                          Yes                     Global      No
bdb_lock_detect                                                            
bdb_log_buffer_sizeYes         Yes         Yes                     Global      No
bdb-logdir     Yes         Yes                                 Global      No
- _Variable_:                          Yes                     Global      No
bdb_logdir                                                                 
bdb_max_lock   Yes         Yes         Yes                     Global      No
bdb-no-recover Yes         Yes                                             
bdb-shared-dataYes         Yes                                 Global      No
- _Variable_:                          Yes                     Global      No
bdb_shared_data                                                            
bdb-tmpdir     Yes         Yes                                 Global      No
- _Variable_:                          Yes                     Global      No
bdb_tmpdir                                                                 
big-tables     Yes         Yes                                 Session     Yes
- _Variable_:                          Yes                     Session     Yes
big_tables                                                                 
bind-address   Yes         Yes         Yes                     Global      No
Binlog_cache_disk_use                                    Yes         Global      No
binlog_cache_sizeYes         Yes         Yes                     Global      Yes
Binlog_cache_use                                    Yes         Global      No
binlog-do-db   Yes         Yes                                             
binlog-ignore-dbYes         Yes                                             
bootstrap      Yes         Yes                                             
bulk_insert_buffer_sizeYes         Yes         Yes                     Both        Yes
Bytes_received                                     Yes         Both        No
Bytes_sent                                         Yes         Both        No
character_set_client                        Yes                     Both        Yes
character-set-client-handshakeYes         Yes                                             
character_set_connection                        Yes                     Both        Yes
character_set_database                        Yes                     Both        Yes
This option                                                                
is dynamic,                                                                
but only the                                                               
server should                                                              
set this                                                                   
information.                                                               
You should                                                                 
not set the                                                                
value of this                                                              
variable                                                                   
manually.                                                                  
character-set-filesystemYes         Yes                                 Both        Yes
- _Variable_:                          Yes                     Both        Yes
character_set_filesystem                                                            
character_set_results                        Yes                     Both        Yes
character-set-serverYes         Yes                                 Both        Yes
- _Variable_:                          Yes                     Both        Yes
character_set_server                                                            
character_set_system                        Yes                     Global      No
character-sets-dirYes         Yes                                 Global      No
- _Variable_:                          Yes                     Global      No
character_sets_dir                                                            
chroot         Yes         Yes                                             
collation_connection                        Yes                     Both        Yes
collation_database                        Yes                     Both        Yes
This option                                                                
is dynamic,                                                                
but only the                                                               
server should                                                              
set this                                                                   
information.                                                               
You should                                                                 
not set the                                                                
value of this                                                              
variable                                                                   
manually.                                                                  
collation-serverYes         Yes                                 Both        Yes
- _Variable_:                          Yes                     Both        Yes
collation_server                                                            
Com_admin_commands                                    Yes         Both        No
Com_alter_db                                       Yes         Both        No
Com_alter_event                                    Yes         Both        No
Com_alter_table                                    Yes         Both        No
Com_analyze                                        Yes         Both        No
Com_backup_table                                    Yes         Both        No
Com_begin                                          Yes         Both        No
Com_call_procedure                                    Yes         Both        No
Com_change_db                                      Yes         Both        No
Com_change_master                                    Yes         Both        No
Com_check                                          Yes         Both        No
Com_checksum                                       Yes         Both        No
Com_commit                                         Yes         Both        No
Com_create_db                                      Yes         Both        No
Com_create_event                                    Yes         Both        No
Com_create_function                                    Yes         Both        No
Com_create_index                                    Yes         Both        No
Com_create_table                                    Yes         Both        No
Com_create_user                                    Yes         Both        No
Com_dealloc_sql                                    Yes         Both        No
Com_delete                                         Yes         Both        No
Com_delete_multi                                    Yes         Both        No
Com_do                                             Yes         Both        No
Com_drop_db                                        Yes         Both        No
Com_drop_event                                     Yes         Both        No
Com_drop_function                                    Yes         Both        No
Com_drop_index                                     Yes         Both        No
Com_drop_table                                     Yes         Both        No
Com_drop_user                                      Yes         Both        No
Com_execute_sql                                    Yes         Both        No
Com_flush                                          Yes         Both        No
Com_grant                                          Yes         Both        No
Com_ha_close                                       Yes         Both        No
Com_ha_open                                        Yes         Both        No
Com_ha_read                                        Yes         Both        No
Com_help                                           Yes         Both        No
Com_insert                                         Yes         Both        No
Com_insert_select                                    Yes         Both        No
Com_kill                                           Yes         Both        No
Com_load                                           Yes         Both        No
Com_lock_tables                                    Yes         Both        No
Com_optimize                                       Yes         Both        No
Com_preload_keys                                    Yes         Both        No
Com_prepare_sql                                    Yes         Both        No
Com_purge                                          Yes         Both        No
Com_purge_before_date                                    Yes         Both        No
Com_rename_table                                    Yes         Both        No
Com_repair                                         Yes         Both        No
Com_replace                                        Yes         Both        No
Com_replace_select                                    Yes         Both        No
Com_reset                                          Yes         Both        No
Com_restore_table                                    Yes         Both        No
Com_revoke                                         Yes         Both        No
Com_revoke_all                                     Yes         Both        No
Com_rollback                                       Yes         Both        No
Com_savepoint                                      Yes         Both        No
Com_select                                         Yes         Both        No
Com_set_option                                     Yes         Both        No
Com_show_binlog_events                                    Yes         Both        No
Com_show_binlogs                                    Yes         Both        No
Com_show_charsets                                    Yes         Both        No
Com_show_collations                                    Yes         Both        No
Com_show_column_types                                    Yes         Both        No
Com_show_create_db                                    Yes         Both        No
Com_show_create_event                                    Yes         Both        No
Com_show_create_table                                    Yes         Both        No
Com_show_databases                                    Yes         Both        No
Com_show_engine_logs                                    Yes         Both        No
Com_show_engine_mutex                                    Yes         Both        No
Com_show_engine_status                                    Yes         Both        No
Com_show_errors                                    Yes         Both        No
Com_show_events                                    Yes         Both        No
Com_show_fields                                    Yes         Both        No
Com_show_grants                                    Yes         Both        No
Com_show_innodb_status                                    Yes         Both        No
Com_show_keys                                      Yes         Both        No
Com_show_logs                                      Yes         Both        No
Com_show_master_status                                    Yes         Both        No
Com_show_ndb_status                                    Yes         Both        No
Com_show_new_master                                    Yes         Both        No
Com_show_open_tables                                    Yes         Both        No
Com_show_plugins                                    Yes         Both        No
Com_show_privileges                                    Yes         Both        No
Com_show_processlist                                    Yes         Both        No
Com_show_slave_hosts                                    Yes         Both        No
Com_show_slave_status                                    Yes         Both        No
Com_show_status                                    Yes         Both        No
Com_show_storage_engines                                    Yes         Both        No
Com_show_tables                                    Yes         Both        No
Com_show_triggers                                    Yes         Both        No
Com_show_variables                                    Yes         Both        No
Com_show_warnings                                    Yes         Both        No
Com_slave_start                                    Yes         Both        No
Com_slave_stop                                     Yes         Both        No
Com_stmt_close                                     Yes         Both        No
Com_stmt_execute                                    Yes         Both        No
Com_stmt_fetch                                     Yes         Both        No
Com_stmt_prepare                                    Yes         Both        No
Com_stmt_reset                                     Yes         Both        No
Com_stmt_send_long_data                                    Yes         Both        No
Com_truncate                                       Yes         Both        No
Com_unlock_tables                                    Yes         Both        No
Com_update                                         Yes         Both        No
Com_update_multi                                    Yes         Both        No
Com_xa_commit                                      Yes         Both        No
Com_xa_end                                         Yes         Both        No
Com_xa_prepare                                     Yes         Both        No
Com_xa_recover                                     Yes         Both        No
Com_xa_rollback                                    Yes         Both        No
Com_xa_start                                       Yes         Both        No
completion_typeYes         Yes         Yes                     Both        Yes
Compression                                        Yes         Session     No
concurrent_insertYes         Yes         Yes                     Global      Yes
connect_timeoutYes         Yes         Yes                     Global      Yes
Connections                                        Yes         Global      No
console        Yes         Yes                                             
core-file      Yes         Yes                                             
Created_tmp_disk_tables                                    Yes         Both        No
Created_tmp_files                                    Yes         Global      No
Created_tmp_tables                                    Yes         Both        No
datadir        Yes         Yes         Yes                     Global      No
date_format                            Yes                     Both        No
datetime_format                        Yes                     Both        No
debug          Yes         Yes         Yes                     Both        Yes
default-character-setYes         Yes                                             
default-storage-engineYes         Yes         Yes                     Both        Yes
default-table-typeYes         Yes                                             
default-time-zoneYes         Yes                                             
default_week_formatYes         Yes         Yes                     Both        Yes
defaults-extra-fileYes                                                         
defaults-file  Yes                                                         
defaults-group-suffixYes                                                         
delay-key-writeYes         Yes                                 Global      Yes
- _Variable_:                          Yes                     Global      Yes
delay_key_write                                                            
Delayed_errors                                     Yes         Global      No
delayed_insert_limitYes         Yes         Yes                     Global      Yes
Delayed_insert_threads                                    Yes         Global      No
delayed_insert_timeoutYes         Yes         Yes                     Global      Yes
delayed_queue_sizeYes         Yes         Yes                     Global      Yes
Delayed_writes                                     Yes         Global      No
des-key-file   Yes         Yes                                             
disconnect-slave-event-countYes         Yes                                             
div_precision_incrementYes         Yes         Yes                     Both        Yes
enable-locking Yes         Yes                                             
enable-named-pipeYes         Yes                                             
- _Variable_:                                                              
named_pipe                                                                 
enable-pstack  Yes         Yes                                             
engine-condition-pushdownYes         Yes                                 Both        Yes
- _Variable_:                          Yes                     Both        Yes
engine_condition_pushdown                                                            
error_count                            Yes                     Session     No
exit-info      Yes         Yes                                             
expire_logs_daysYes         Yes         Yes                     Global      Yes
external-lockingYes         Yes                                             
- _Variable_:                                                              
skip_external_locking                                                            
flush          Yes         Yes         Yes                     Global      Yes
Flush_commands                                     Yes         Global      No
flush_time     Yes         Yes         Yes                     Global      Yes
foreign_key_checks                        Yes                     Session     Yes
ft_boolean_syntaxYes         Yes         Yes                     Global      Yes
ft_max_word_lenYes         Yes         Yes                     Global      No
ft_min_word_lenYes         Yes         Yes                     Global      No
ft_query_expansion_limitYes         Yes         Yes                     Global      No
ft_stopword_fileYes         Yes         Yes                     Global      No
gdb            Yes         Yes                                             
group_concat_max_lenYes         Yes         Yes                     Both        Yes
Handler_commit                                     Yes         Both        No
Handler_delete                                     Yes         Both        No
Handler_discover                                    Yes         Both        No
Handler_prepare                                    Yes         Both        No
Handler_read_first                                    Yes         Both        No
Handler_read_key                                    Yes         Both        No
Handler_read_next                                    Yes         Both        No
Handler_read_prev                                    Yes         Both        No
Handler_read_rnd                                    Yes         Both        No
Handler_read_rnd_next                                    Yes         Both        No
Handler_rollback                                    Yes         Both        No
Handler_savepoint                                    Yes         Both        No
Handler_savepoint_rollback                                    Yes         Both        No
Handler_update                                     Yes         Both        No
Handler_write                                      Yes         Both        No
have_archive                           Yes                     Global      No
have_bdb                               Yes                     Global      No
have_blackhole_engine                        Yes                     Global      No
have_compress                          Yes                     Global      No
have_crypt                             Yes                     Global      No
have_csv                               Yes                     Global      No
have_example_engine                        Yes                     Global      No
have_federated_engine                        Yes                     Global      No
have_geometry                          Yes                     Global      No
have_innodb                            Yes                     Global      No
have_isam                              Yes                     Global      No
have_merge_engine                        Yes                     Global      No
have_ndbcluster                        Yes                     Global      No
have_openssl                           Yes                     Global      No
have_query_cache                        Yes                     Global      No
have_raid                              Yes                     Global      No
have_rtree_keys                        Yes                     Global      No
have_ssl                               Yes                     Global      No
have_symlink                           Yes                     Global      No
help           Yes         Yes                                             
hostname                               Yes                     Global      No
identity                               Yes                     Session     Yes
init_connect   Yes         Yes         Yes                     Global      Yes
init-file      Yes         Yes                                 Global      No
- _Variable_:                          Yes                     Global      No
init_file                                                                  
init-rpl-role  Yes         Yes                                             
init_slave     Yes         Yes         Yes                     Global      Yes
innodb         Yes         Yes                                             
innodb_adaptive_hash_indexYes         Yes         Yes                     Global      No
innodb_additional_mem_pool_sizeYes         Yes         Yes                     Global      No
innodb_autoextend_incrementYes         Yes         Yes                     Global      Yes
innodb_buffer_pool_awe_mem_mbYes         Yes         Yes                     Global      No
Innodb_buffer_pool_pages_data                                    Yes         Global      No
Innodb_buffer_pool_pages_dirty                                    Yes         Global      No
Innodb_buffer_pool_pages_flushed                                    Yes         Global      No
Innodb_buffer_pool_pages_free                                    Yes         Global      No
Innodb_buffer_pool_pages_latched                                    Yes         Global      No
Innodb_buffer_pool_pages_misc                                    Yes         Global      No
Innodb_buffer_pool_pages_total                                    Yes         Global      No
Innodb_buffer_pool_read_ahead_rnd                                    Yes         Global      No
Innodb_buffer_pool_read_ahead_seq                                    Yes         Global      No
Innodb_buffer_pool_read_requests                                    Yes         Global      No
Innodb_buffer_pool_reads                                    Yes         Global      No
innodb_buffer_pool_sizeYes         Yes         Yes                     Global      No
Innodb_buffer_pool_wait_free                                    Yes         Global      No
Innodb_buffer_pool_write_requests                                    Yes         Global      No
innodb_checksumsYes         Yes         Yes                     Global      No
innodb_commit_concurrencyYes         Yes         Yes                     Global      Yes
innodb_concurrency_ticketsYes         Yes         Yes                     Global      Yes
innodb_data_file_pathYes         Yes         Yes                     Global      No
Innodb_data_fsyncs                                    Yes         Global      No
innodb_data_home_dirYes         Yes         Yes                     Global      No
Innodb_data_pending_fsyncs                                    Yes         Global      No
Innodb_data_pending_reads                                    Yes         Global      No
Innodb_data_pending_writes                                    Yes         Global      No
Innodb_data_read                                    Yes         Global      No
Innodb_data_reads                                    Yes         Global      No
Innodb_data_writes                                    Yes         Global      No
Innodb_data_written                                    Yes         Global      No
Innodb_dblwr_pages_written                                    Yes         Global      No
Innodb_dblwr_writes                                    Yes         Global      No
innodb_doublewriteYes         Yes         Yes                     Global      No
innodb_fast_shutdownYes         Yes         Yes                     Global      Yes
innodb_file_io_threadsYes         Yes         Yes                     Global      No
innodb_file_per_tableYes         Yes         Yes                     Global      No
innodb_flush_log_at_trx_commitYes         Yes         Yes                     Global      Yes
innodb_flush_methodYes         Yes         Yes                     Global      No
innodb_force_recoveryYes         Yes         Yes                     Global      No
innodb_lock_wait_timeoutYes         Yes         Yes                     Global      No
innodb_locks_unsafe_for_binlogYes         Yes         Yes                     Global      No
innodb_log_arch_dirYes         Yes         Yes                     Global      No
innodb_log_archiveYes         Yes         Yes                     Global      No
innodb_log_buffer_sizeYes         Yes         Yes                     Global      No
innodb_log_file_sizeYes         Yes         Yes                     Global      No
innodb_log_files_in_groupYes         Yes         Yes                     Global      No
innodb_log_group_home_dirYes         Yes         Yes                     Global      No
Innodb_log_waits                                    Yes         Global      No
Innodb_log_write_requests                                    Yes         Global      No
Innodb_log_writes                                    Yes         Global      No
innodb_max_dirty_pages_pctYes         Yes         Yes                     Global      Yes
innodb_max_purge_lagYes         Yes         Yes                     Global      Yes
innodb_mirrored_log_groupsYes         Yes         Yes                     Global      No
innodb_open_filesYes         Yes         Yes                     Global      No
Innodb_os_log_fsyncs                                    Yes         Global      No
Innodb_os_log_pending_fsyncs                                    Yes         Global      No
Innodb_os_log_pending_writes                                    Yes         Global      No
Innodb_os_log_written                                    Yes         Global      No
Innodb_page_size                                    Yes         Global      No
Innodb_pages_created                                    Yes         Global      No
Innodb_pages_read                                    Yes         Global      No
Innodb_pages_written                                    Yes         Global      No
innodb_rollback_on_timeoutYes         Yes         Yes                     Global      No
Innodb_row_lock_current_waits                                    Yes         Global      No
Innodb_row_lock_time                                    Yes         Global      No
Innodb_row_lock_time_avg                                    Yes         Global      No
Innodb_row_lock_time_max                                    Yes         Global      No
Innodb_row_lock_waits                                    Yes         Global      No
Innodb_rows_deleted                                    Yes         Global      No
Innodb_rows_inserted                                    Yes         Global      No
Innodb_rows_read                                    Yes         Global      No
Innodb_rows_updated                                    Yes         Global      No
innodb-safe-binlogYes         Yes                                             
innodb-status-fileYes         Yes         Yes                     Global      No
innodb_support_xaYes         Yes         Yes                     Both        Yes
innodb_sync_spin_loopsYes         Yes         Yes                     Global      Yes
innodb_table_locksYes         Yes         Yes                     Both        Yes
innodb_thread_concurrencyYes         Yes         Yes                     Global      Yes
innodb_thread_sleep_delayYes         Yes         Yes                     Global      Yes
innodb_use_legacy_cardinality_algorithmYes         Yes         Yes                     Global      Yes
insert_id                              Yes                     Session     Yes
install        Yes                                                         
install-manual Yes                                                         
interactive_timeoutYes         Yes         Yes                     Both        Yes
join_buffer_sizeYes         Yes         Yes                     Both        Yes
keep_files_on_createYes         Yes         Yes                     Both        Yes
Key_blocks_not_flushed                                    Yes         Global      No
Key_blocks_unused                                    Yes         Global      No
Key_blocks_used                                    Yes         Global      No
key_buffer_sizeYes         Yes         Yes                     Global      Yes
key_cache_age_thresholdYes         Yes         Yes                     Global      Yes
key_cache_block_sizeYes         Yes         Yes                     Global      Yes
key_cache_division_limitYes         Yes         Yes                     Global      Yes
Key_read_requests                                    Yes         Global      No
Key_reads                                          Yes         Global      No
Key_write_requests                                    Yes         Global      No
Key_writes                                         Yes         Global      No
language       Yes         Yes         Yes                     Global      No
large_files_support                        Yes                     Global      No
large_page_size                        Yes                     Global      No
large-pages    Yes         Yes                                 Global      No
- _Variable_:                          Yes                     Global      No
large_pages                                                                
last_insert_id                         Yes                     Session     Yes
Last_query_cost                                    Yes         Session     No
lc_time_names                          Yes                     Both        Yes
license                                Yes                     Global      No
local_infile                           Yes                     Global      Yes
local-infile   Yes         Yes                                             
- _Variable_:                                                              
local_infile                                                               
locked_in_memory                        Yes                     Global      No
log            Yes         Yes         Yes                     Global      No
log_bin                                Yes                     Global      No
log-bin        Yes         Yes         Yes                     Global      No
log-bin-index  Yes         Yes                                             
log-bin-trust-function-creatorsYes         Yes                                 Global      Yes
- _Variable_:                          Yes                     Global      Yes
log_bin_trust_function_creators                                                            
log-bin-trust-routine-creatorsYes         Yes                                 Global      Yes
- _Variable_:                          Yes                     Global      Yes
log_bin_trust_routine_creators                                                            
log-error      Yes         Yes                                 Global      No
- _Variable_:                          Yes                     Global      No
log_error                                                                  
log-isam       Yes         Yes                                             
log-queries-not-using-indexesYes         Yes                                 Global      Yes
- _Variable_:                          Yes                     Global      Yes
log_queries_not_using_indexes                                                            
log-short-formatYes         Yes                                             
log-slave-updatesYes         Yes                                 Global      No
- _Variable_:                          Yes                     Global      No
log_slave_updates                                                            
log-slow-admin-statementsYes         Yes                                             
log-slow-queriesYes         Yes                                 Global      No
- _Variable_:                          Yes                     Global      No
log_slow_queries                                                            
log-tc         Yes         Yes                                             
log-tc-size    Yes         Yes                                             
log-warnings   Yes         Yes                                 Both        Yes
- _Variable_:                          Yes                     Both        Yes
log_warnings                                                               
long_query_timeYes         Yes         Yes                     Both        Yes
low-priority-updatesYes         Yes                                 Both        Yes
- _Variable_:                          Yes                     Both        Yes
low_priority_updates                                                            
lower_case_file_systemYes         Yes         Yes                     Global      No
lower_case_table_namesYes         Yes         Yes                     Global      No
master-connect-retryYes         Yes                                             
master-host    Yes         Yes                                             
master-info-fileYes         Yes                                             
master-passwordYes         Yes                                             
master-port    Yes         Yes                                             
master-retry-countYes         Yes                                             
master-ssl     Yes         Yes                                             
master-ssl-ca  Yes         Yes                                             
master-ssl-capathYes         Yes                                             
master-ssl-certYes         Yes                                             
master-ssl-cipherYes         Yes                                             
master-ssl-key Yes         Yes                                             
master-user    Yes         Yes                                             
max_allowed_packetYes         Yes         Yes                     Global      Yes
max_binlog_cache_sizeYes         Yes         Yes                     Global      Yes
max-binlog-dump-eventsYes         Yes                                             
max_binlog_sizeYes         Yes         Yes                     Global      Yes
max_connect_errorsYes         Yes         Yes                     Global      Yes
max_connectionsYes         Yes         Yes                     Global      Yes
max_delayed_threadsYes         Yes         Yes                     Both        Yes
max_error_countYes         Yes         Yes                     Both        Yes
max_heap_table_sizeYes         Yes         Yes                     Both        Yes
max_insert_delayed_threads                        Yes                     Both        Yes
max_join_size  Yes         Yes         Yes                     Both        Yes
max_length_for_sort_dataYes         Yes         Yes                     Both        Yes
max_prepared_stmt_countYes         Yes         Yes                     Global      Yes
max_relay_log_sizeYes         Yes         Yes                     Global      Yes
max_seeks_for_keyYes         Yes         Yes                     Both        Yes
max_sort_lengthYes         Yes         Yes                     Both        Yes
max_sp_recursion_depthYes         Yes         Yes                     Both        Yes
max_tmp_tables Yes         Yes         Yes                     Both        Yes
Max_used_connections                                    Yes         Global      No
max_user_connectionsYes         Yes         Yes                     Both        Yes
max_write_lock_countYes         Yes         Yes                     Global      Yes
memlock        Yes         Yes         Yes                     Global      No
merge          Yes         Yes                                             
multi_range_countYes         Yes         Yes                     Both        Yes
myisam-block-sizeYes         Yes                                             
myisam_data_pointer_sizeYes         Yes         Yes                     Global      Yes
myisam_max_extra_sort_file_sizeYes         Yes         Yes                     Global      No
myisam_max_sort_file_sizeYes         Yes         Yes                     Global      Yes
myisam_mmap_sizeYes         Yes         Yes                     Global      No
myisam-recover Yes         Yes                                             
- _Variable_:                                                              
myisam_recover_options                                                            
myisam_recover_options                        Yes                     Global      No
myisam_repair_threadsYes         Yes         Yes                     Both        Yes
myisam_sort_buffer_sizeYes         Yes         Yes                     Both        Yes
myisam_stats_methodYes         Yes         Yes                     Both        Yes
named_pipe                             Yes                     Global      No
ndb_autoincrement_prefetch_szYes         Yes         Yes                     Both        Yes
ndb_cache_check_timeYes         Yes         Yes                     Global      Yes
Ndb_cluster_node_id                                    Yes         Both        No
Ndb_config_from_host                                    Yes         Both        No
Ndb_config_from_port                                    Yes         Both        No
ndb_force_send Yes         Yes         Yes                     Both        Yes
ndb_index_stat_cache_entriesYes         Yes                                             
ndb_index_stat_enableYes         Yes                                             
ndb_index_stat_update_freqYes         Yes                                             
ndb-mgmd-host  Yes         Yes                                             
ndb-nodeid     Yes         Yes                     Yes         Global      No
ndb_optimized_node_selectionYes         Yes                                             
ndb_report_thresh_binlog_epoch_slipYes         Yes                                             
ndb_report_thresh_binlog_mem_usageYes         Yes                                             
ndb_use_exact_count                        Yes                     Both        Yes
ndb_use_transactionsYes         Yes         Yes                     Both        Yes
ndbcluster     Yes         Yes                                             
- _Variable_:                                                              
have_ndbcluster                                                            
net_buffer_lengthYes         Yes         Yes                     Both        Yes
net_read_timeoutYes         Yes         Yes                     Both        Yes
net_retry_countYes         Yes         Yes                     Both        Yes
net_write_timeoutYes         Yes         Yes                     Both        Yes
new            Yes         Yes         Yes                     Both        Yes
no-defaults    Yes                                                         
Not_flushed_delayed_rows                                    Yes         Global      No
old-passwords  Yes         Yes                                 Both        Yes
- _Variable_:                          Yes                     Both        Yes
old_passwords                                                              
old-style-user-limitsYes         Yes                                             
one-thread     Yes         Yes                                             
Open_files                                         Yes         Global      No
open-files-limitYes         Yes                                 Global      No
- _Variable_:                          Yes                     Global      No
open_files_limit                                                            
Open_streams                                       Yes         Global      No
Open_tables                                        Yes         Both        No
Opened_tables                                      Yes         Both        No
optimizer_prune_levelYes         Yes         Yes                     Both        Yes
optimizer_search_depthYes         Yes         Yes                     Both        Yes
pid-file       Yes         Yes                                 Global      No
- _Variable_:                          Yes                     Global      No
pid_file                                                                   
plugin_dir     Yes         Yes         Yes                     Global      No
port           Yes         Yes         Yes                     Global      No
port-open-timeoutYes         Yes                                             
preload_buffer_sizeYes         Yes         Yes                     Both        Yes
prepared_stmt_count                        Yes                     Global      No
Prepared_stmt_count                                    Yes         Global      No
print-defaults Yes                                                         
profiling                              Yes                     Session     Yes
profiling_history_size                        Yes                     Both        Yes
protocol_version                        Yes                     Global      No
pseudo_thread_id                        Yes                     Session     Yes
Qcache_free_blocks                                    Yes         Global      No
Qcache_free_memory                                    Yes         Global      No
Qcache_hits                                        Yes         Global      No
Qcache_inserts                                     Yes         Global      No
Qcache_lowmem_prunes                                    Yes         Global      No
Qcache_not_cached                                    Yes         Global      No
Qcache_queries_in_cache                                    Yes         Global      No
Qcache_total_blocks                                    Yes         Global      No
Queries                                            Yes         Both        No
query_alloc_block_sizeYes         Yes         Yes                     Both        Yes
query_cache_limitYes         Yes         Yes                     Global      Yes
query_cache_min_res_unitYes         Yes         Yes                     Global      Yes
query_cache_sizeYes         Yes         Yes                     Global      Yes
query_cache_typeYes         Yes         Yes                     Both        Yes
query_cache_wlock_invalidateYes         Yes         Yes                     Both        Yes
query_prealloc_sizeYes         Yes         Yes                     Both        Yes
Questions                                          Yes         Both        No
rand_seed1                             Yes                     Session     Yes
rand_seed2                             Yes                     Session     Yes
range_alloc_block_sizeYes         Yes         Yes                     Both        Yes
read_buffer_sizeYes         Yes         Yes                     Both        Yes
read_only      Yes         Yes         Yes                     Global      Yes
read_rnd_buffer_sizeYes         Yes         Yes                     Both        Yes
relay-log      Yes         Yes                                             
relay-log-indexYes         Yes                                 Both        No
- _Variable_:                          Yes                     Both        No
relay_log_index                                                            
relay_log_indexYes         Yes         Yes                     Global      No
relay-log-info-fileYes         Yes                                             
- _Variable_:                                                              
relay_log_info_file                                                            
relay_log_info_fileYes         Yes         Yes                     Global      No
relay_log_purgeYes         Yes         Yes                     Global      Yes
relay_log_space_limitYes         Yes         Yes                     Global      No
remove         Yes                                                         
replicate-do-dbYes         Yes                                             
replicate-do-tableYes         Yes                                             
replicate-ignore-dbYes         Yes                                             
replicate-ignore-tableYes         Yes                                             
replicate-rewrite-dbYes         Yes                                             
replicate-same-server-idYes         Yes                                             
replicate-wild-do-tableYes         Yes                                             
replicate-wild-ignore-tableYes         Yes                                             
report-host    Yes         Yes                                 Global      No
- _Variable_:                          Yes                     Global      No
report_host                                                                
report-passwordYes         Yes                                 Global      No
- _Variable_:                          Yes                     Global      No
report_password                                                            
report-port    Yes         Yes                                 Global      No
- _Variable_:                          Yes                     Global      No
report_port                                                                
report-user    Yes         Yes                                 Global      No
- _Variable_:                          Yes                     Global      No
report_user                                                                
rpl_recovery_rank                        Yes                     Global      Yes
Rpl_status                                         Yes         Global      No
safe-mode      Yes         Yes                                             
safe-show-databaseYes         Yes         Yes                     Global      Yes
safe-user-createYes         Yes                                             
safemalloc-mem-limitYes         Yes                                             
secure-auth    Yes         Yes                                 Global      Yes
- _Variable_:                          Yes                     Global      Yes
secure_auth                                                                
secure-file-privYes         Yes                                 Global      No
- _Variable_:                          Yes                     Global      No
secure_file_priv                                                            
Select_full_join                                    Yes         Both        No
Select_full_range_join                                    Yes         Both        No
Select_range                                       Yes         Both        No
Select_range_check                                    Yes         Both        No
Select_scan                                        Yes         Both        No
server-id      Yes         Yes                                 Global      Yes
- _Variable_:                          Yes                     Global      Yes
server_id                                                                  
set-variable   Yes         Yes                                             
shared_memory                          Yes                     Global      No
shared_memory_base_name                        Yes                     Global      No
show-slave-auth-infoYes         Yes                                             
skip-bdb       Yes         Yes                                             
skip-character-set-client-handshakeYes         Yes                                             
skip-concurrent-insertYes         Yes                                             
- _Variable_:                                                              
concurrent_insert                                                            
skip-external-lockingYes         Yes                                 Global      No
- _Variable_:                          Yes                     Global      No
skip_external_locking                                                            
skip-grant-tablesYes         Yes                                             
skip-host-cacheYes         Yes                                             
skip-locking   Yes         Yes                                             
skip-log-warningsYes                                                         
skip-merge     Yes         Yes                                             
- _Variable_:                                                              
skip-name-resolveYes         Yes                                 Global      No
- _Variable_:                          Yes                     Global      No
skip_name_resolve                                                            
skip-networkingYes         Yes                                 Global      No
- _Variable_:                          Yes                     Global      No
skip_networking                                                            
skip-new       Yes         Yes                                             
skip-safemallocYes         Yes                                             
skip-show-databaseYes         Yes                                 Global      No
- _Variable_:                          Yes                     Global      No
skip_show_database                                                            
skip-slave-startYes         Yes                                             
skip-ssl       Yes         Yes                                             
skip-stack-traceYes         Yes                                             
skip-symbolic-linksYes                                                         
skip-symlink   Yes         Yes                                             
skip-sync-bdb-logsYes         Yes         Yes                     Global      No
skip-thread-priorityYes         Yes                                             
slave_compressed_protocolYes         Yes         Yes                     Global      Yes
slave-load-tmpdirYes         Yes                                 Global      No
- _Variable_:                          Yes                     Global      No
slave_load_tmpdir                                                            
slave-net-timeoutYes         Yes                                 Global      Yes
- _Variable_:                          Yes                     Global      Yes
slave_net_timeout                                                            
Slave_open_temp_tables                                    Yes         Global      No
Slave_retried_transactions                                    Yes         Global      No
Slave_running                                      Yes         Global      No
slave-skip-errorsYes         Yes                                 Global      No
- _Variable_:                          Yes                     Global      No
slave_skip_errors                                                            
slave_transaction_retriesYes         Yes         Yes                     Global      Yes
Slow_launch_threads                                    Yes         Both        No
slow_launch_timeYes         Yes         Yes                     Global      Yes
Slow_queries                                       Yes         Both        No
socket         Yes         Yes         Yes                     Global      No
sort_buffer_sizeYes         Yes         Yes                     Both        Yes
Sort_merge_passes                                    Yes         Both        No
Sort_range                                         Yes         Both        No
Sort_rows                                          Yes         Both        No
Sort_scan                                          Yes         Both        No
sporadic-binlog-dump-failYes         Yes                                             
sql_auto_is_null                        Yes                     Session     Yes
sql_big_selects                        Yes                     Session     Yes
sql_big_tables                         Yes                     Session     Yes
sql_buffer_result                        Yes                     Session     Yes
sql_log_bin                            Yes                     Session     Yes
sql_log_off                            Yes                     Session     Yes
sql_log_update                         Yes                     Session     Yes
sql_low_priority_updates                        Yes                     Both        Yes
sql_max_join_size                        Yes                     Both        Yes
sql-mode       Yes         Yes                                 Both        Yes
- _Variable_:                          Yes                     Both        Yes
sql_mode                                                                   
sql_notes                              Yes                     Session     Yes
sql_quote_show_create                        Yes                     Session     Yes
sql_safe_updates                        Yes                     Session     Yes
sql_select_limit                        Yes                     Both        Yes
sql_slave_skip_counter                        Yes                     Global      Yes
sql_warnings                           Yes                     Session     Yes
ssl            Yes         Yes                                             
Ssl_accept_renegotiates                                    Yes         Global      No
Ssl_accepts                                        Yes         Global      No
ssl-ca         Yes         Yes                                 Global      No
- _Variable_:                          Yes                     Global      No
ssl_ca                                                                     
Ssl_callback_cache_hits                                    Yes         Global      No
ssl-capath     Yes         Yes                                 Global      No
- _Variable_:                          Yes                     Global      No
ssl_capath                                                                 
ssl-cert       Yes         Yes                                 Global      No
- _Variable_:                          Yes                     Global      No
ssl_cert                                                                   
ssl-cipher     Yes         Yes                                 Global      No
- _Variable_:                          Yes                     Global      No
ssl_cipher                                                                 
Ssl_cipher                                         Yes         Both        No
Ssl_cipher_list                                    Yes         Both        No
Ssl_client_connects                                    Yes         Global      No
Ssl_connect_renegotiates                                    Yes         Global      No
Ssl_ctx_verify_depth                                    Yes         Global      No
Ssl_ctx_verify_mode                                    Yes         Global      No
Ssl_default_timeout                                    Yes         Both        No
Ssl_finished_accepts                                    Yes         Global      No
Ssl_finished_connects                                    Yes         Global      No
ssl-key        Yes         Yes                                 Global      No
- _Variable_:                          Yes                     Global      No
ssl_key                                                                    
Ssl_session_cache_hits                                    Yes         Global      No
Ssl_session_cache_misses                                    Yes         Global      No
Ssl_session_cache_mode                                    Yes         Global      No
Ssl_session_cache_overflows                                    Yes         Global      No
Ssl_session_cache_size                                    Yes         Global      No
Ssl_session_cache_timeouts                                    Yes         Global      No
Ssl_sessions_reused                                    Yes         Both        No
Ssl_used_session_cache_entries                                    Yes         Global      No
Ssl_verify_depth                                    Yes         Both        No
Ssl_verify_mode                                    Yes         Both        No
Ssl_version                                        Yes         Both        No
standalone     Yes         Yes                                             
storage_engine                         Yes                     Both        Yes
symbolic-links Yes         Yes                                             
sync-bdb-logs  Yes         Yes                                 Global      No
- _Variable_:                          Yes                     Global      No
sync_bdb_logs                                                              
sync_binlog    Yes         Yes         Yes                     Global      Yes
sync_frm       Yes         Yes         Yes                     Global      Yes
sysdate-is-now Yes         Yes                                             
system_time_zone                        Yes                     Global      No
table_cache    Yes         Yes         Yes                     Global      Yes
table_lock_wait_timeoutYes         Yes         Yes                     Global      Yes
Table_locks_immediate                                    Yes         Global      No
Table_locks_waited                                    Yes         Global      No
table_type                             Yes                     Both        Yes
tc-heuristic-recoverYes         Yes                                             
Tc_log_max_pages_used                                    Yes         Global      No
Tc_log_page_size                                    Yes         Global      No
Tc_log_page_waits                                    Yes         Global      No
temp-pool      Yes         Yes                                             
thread_cache_sizeYes         Yes         Yes                     Global      Yes
thread_concurrencyYes         Yes         Yes                     Global      No
thread_stack   Yes         Yes         Yes                     Global      No
Threads_cached                                     Yes         Global      No
Threads_connected                                    Yes         Global      No
Threads_created                                    Yes         Global      No
Threads_running                                    Yes         Global      No
time_format                            Yes                     Both        No
time_zone      Yes         Yes         Yes                     Both        Yes
timed_mutexes  Yes         Yes         Yes                     Global      Yes
timestamp                              Yes                     Session     Yes
tmp_table_size Yes         Yes         Yes                     Both        Yes
tmpdir         Yes         Yes         Yes                     Global      No
transaction_alloc_block_sizeYes         Yes         Yes                     Both        Yes
transaction-isolationYes         Yes                                             
- _Variable_:                                                              
tx_isolation                                                               
transaction_prealloc_sizeYes         Yes         Yes                     Both        Yes
tx_isolation                           Yes                     Both        Yes
unique_checks                          Yes                     Session     Yes
updatable_views_with_limitYes         Yes         Yes                     Both        Yes
Uptime                                             Yes         Global      No
Uptime_since_flush_status                                    Yes         Global      No
user           Yes         Yes                                             
verbose        Yes         Yes                                             
version                                Yes                     Global      No
version_comment                        Yes                     Global      No
version_compile_machine                        Yes                     Global      No
version_compile_os                        Yes                     Global      No
wait_timeout   Yes         Yes         Yes                     Both        Yes
warning_count                          Yes                     Session     No
warnings       Yes         Yes                                             


File: manual.info,  Node: server-options,  Next: server-system-variables,  Prev: mysqld-option-tables,  Up: mysqld-server

6.1.2 Server Command Options
----------------------------

When you start the *Note `mysqld': mysqld. server, you can specify
program options using any of the methods described in *Note
program-options::. The most common methods are to provide options in an
option file or on the command line. However, in most cases it is
desirable to make sure that the server uses the same options each time
it runs. The best way to ensure this is to list them in an option file.
See *Note option-files::.

*Note `mysqld': mysqld. reads options from the `[mysqld]' and `[server]'
groups. *Note `mysqld_safe': mysqld-safe. reads options from the
`[mysqld]', `[server]', `[mysqld_safe]', and `[safe_mysqld]' groups.
*Note `mysql.server': mysql-server. reads options from the `[mysqld]'
and `[mysql.server]' groups.

An embedded MySQL server usually reads options from the `[server]',
`[embedded]', and `[XXXXX_SERVER]' groups, where XXXXX is the name of
the application into which the server is embedded.

*Note `mysqld': mysqld. accepts many command options. For a brief
summary, execute *Note `mysqld --help': mysqld. To see the full list,
use *Note `mysqld --verbose --help': mysqld.

The following list shows some of the most common server options.
Additional options are described in other sections:

   * Options that affect security: See *Note privileges-options::.

   * SSL-related options: See *Note ssl-options::.

   * Binary log control options: See *Note
     replication-options-binary-log::.

   * Replication-related options: See *Note replication-options::.

   * Options specific to particular storage engines: See *Note
     myisam-start::, *Note bdb-start::, *Note innodb-parameters::, and
     *Note mysql-cluster-program-options-mysqld::.

You can also set the values of server system variables by using
variable names as options, as described at the end of this section.

Some options control the size of buffers or caches. For a given buffer,
the server might need to allocate internal data structures. These
structures typically are allocated from the total memory allocated to
the buffer, and the amount of space required might be platform
dependent. This means that when you assign a value to an option that
controls a buffer size, the amount of space actually available might
differ from the value assigned. In some cases, the amount might be less
than the value assigned. It is also possible that the server will
adjust a value upward. For example, if you assign a value of 0 to an
option for which the minimal value is 1024, the server will set the
value to 1024.

Values for buffer sizes, lengths, and stack sizes are given in bytes
unless otherwise specified.

Some options take file name values. Unless otherwise specified, the
default file location is the data directory if the value is a relative
path name. To specify the location explicitly, use an absolute path
name. Suppose that the data directory is `/var/mysql/data'. If a
file-valued option is given as a relative path name, it will be located
under `/var/mysql/data'. If the value is an absolute path name, its
location is as given by the path name.

   *  `--help', `-?'

     Options for help      *Command-Line        `-?'            
     Format*                              
     **                   `--help'        
     *Option-File Format* `help'          


     Display a short help message and exit. Use both the `--verbose' and
     `--help' options to see the full message.

   *  `--allow-suspicious-udfs'

     Options for allow-suspicious-udfs      *Version Introduced* 5.0.3           
     *Command-Line        `--allow-suspicious-udfs'        
     Format*                              
     *Option-File Format* `allow-suspicious-udfs'        
                          *Permitted        
                          Values          
                          *               
     *Type*               `boolean'        
     *Default*            `FALSE'         


     This option controls whether user-defined functions that have only
     an `xxx' symbol for the main function can be loaded. By default,
     the option is off and only UDFs that have at least one auxiliary
     symbol can be loaded; this prevents attempts at loading functions
     from shared object files other than those containing legitimate
     UDFs. This option was added in version 5.0.3. See *Note
     udf-security::.

   *  `--ansi'

     Options for ansi      *Command-Line        `--ansi'        
     Format*                              
     **                   `-a'            
     *Option-File Format* `ansi'          


     Use standard (ANSI) SQL syntax instead of MySQL syntax. For more
     precise control over the server SQL mode, use the `--sql-mode'
     option instead. See *Note ansi-mode::, and *Note server-sql-mode::.

   *  `--basedir=PATH', `-b PATH'

     Options for basedir      *Command-Line        `--basedir=path'        
     Format*                              
     **                   `-b'            
     *Option-File Format* `basedir'        
     *Option Sets         Yes,            
     Variable*            `basedir'        
     *Variable Name*      `basedir'        
     *Variable Scope*     Global          
     *Dynamic Variable*   No              
                          *Permitted        
                          Values          
                          *               
     *Type*               `file           
                          name'           


     The path to the MySQL installation directory. All paths are
     usually resolved relative to this directory.

   *  `--big-tables'

     Options for big-tables      *Command-Line        `--big-tables'        
     Format*                              
     *Option-File Format* `big-tables'        
     *Option Sets         Yes,            
     Variable*            `big_tables'        
     *Variable Name*      `big-tables'        
     *Variable Scope*     Session         
     *Dynamic Variable*   Yes             
                          *Permitted        
                          Values          
                          *               
     *Type*               `boolean'        


     Enable large result sets by saving all temporary sets in files.
     This option prevents most `table full' errors, but also slows down
     queries for which in-memory tables would suffice. Since MySQL
     3.23.2, the server is able to handle large result sets
     automatically by using memory for small temporary tables and
     switching to disk tables where necessary.

   *  `--bind-address=IP'

     Options for bind-address      *Command-Line        `--bind-address=name'        
     Format*                              
     *Option-File Format* `bind-address=name'        
     *Variable Name*      `bind-address'        
     *Variable Scope*     Global          
     *Dynamic Variable*   No              
                          *Permitted        
                          Values          
                          *               
     *Type*               `string'        
     *Default*            `0.0.0.0'        
     *Range*              `0.0.0.0        
                          ..              
                          255.255.255.255'        


     The IP address to bind to. Only one address can be selected.  If
     this option is specified multiple times, the last address given is
     used.

     If no address or `0.0.0.0' is specified, the server listens on all
     interfaces.

   *  `--bootstrap'

     Options for bootstrap      *Command-Line        `--bootstrap'        
     Format*                              
     *Option-File Format* `bootstrap'        


     This option is used by the *Note `mysql_install_db':
     mysql-install-db.  script to create the MySQL privilege tables
     without having to start a full MySQL server.

     This option is unavailable if MySQL was configured with the
     `--disable-grant-options' option. See *Note
     source-configuration-options::.

   *  `--character-sets-dir=PATH'

     Options for character-sets-dir      *Command-Line        `--character-sets-dir=path'        
     Format*                              
     *Option-File Format* `character-sets-dir=path'        
     *Option Sets         Yes,            
     Variable*            `character_sets_dir'        
     *Variable Name*      `character-sets-dir'        
     *Variable Scope*     Global          
     *Dynamic Variable*   No              
                          *Permitted        
                          Values          
                          *               
     *Type*               `directory        
                          name'           


     The directory where character sets are installed. See *Note
     charset-configuration::.

   *  `--character-set-client-handshake'

     Options for character-set-client-handshake      *Command-Line        `--character-set-client-handshake'        
     Format*                              
     *Option-File Format* `character-set-client-handshake'        
                          *Permitted        
                          Values          
                          *               
     *Type*               `boolean'        
     *Default*            `TRUE'          


     Do not ignore character set information sent by the client. To
     ignore client information and use the default server character
     set, use `--skip-character-set-client-handshake'; this makes MySQL
     behave like MySQL 4.0.

   *  `--character-set-filesystem=CHARSET_NAME'

     Options for character-set-filesystem      *Version Introduced* 5.0.19          
     *Command-Line        `--character-set-filesystem=name'        
     Format*                              
     *Option-File Format* `character-set-filesystem'        
     *Option Sets         Yes,            
     Variable*            `character_set_filesystem'        
     *Variable Name*      `character_set_filesystem'        
     *Variable Scope*     Global,         
                          Session         
     *Dynamic Variable*   Yes             
                          *Permitted        
                          Values          
                          *               
     *Type*               `string'        


     The file system character set. This option sets the
     `character_set_filesystem' system variable. It was added in MySQL
     5.0.19.

   *  `--character-set-server=CHARSET_NAME', `-C CHARSET_NAME'

     Options for character-set-server      *Command-Line        `--character-set-server'        
     Format*                              
     *Option-File Format* `character-set-server'        
     *Option Sets         Yes,            
     Variable*            `character_set_server'        
     *Variable Name*      `character_set_server'        
     *Variable Scope*     Global,         
                          Session         
     *Dynamic Variable*   Yes             
                          *Permitted        
                          Values          
                          *               
     *Type*               `string'        


     Use CHARSET_NAME as the default server character set. See *Note
     charset-configuration::. If you use this option to specify a
     nondefault character set, you should also use `--collation-server'
     to specify the collation.

   *  `--chroot=PATH', `-r PATH'

     Options for chroot      *Command-Line        `--chroot=name'        
     Format*                              
     **                   `-r             
                          name'           
     *Option-File Format* `chroot'        
                          *Permitted        
                          Values          
                          *               
     *Type*               `file           
                          name'           


     Put the *Note `mysqld': mysqld. server in a closed environment
     during startup by using the `chroot()' system call. This is a
     recommended security measure. Note that use of this option
     somewhat limits *Note `LOAD DATA INFILE': load-data. and *Note
     `SELECT ... INTO OUTFILE': select-into.

   *  `--collation-server=COLLATION_NAME'

     Options for collation-server      *Command-Line        `--collation-server'        
     Format*                              
     *Option-File Format* `collation-server'        
     *Option Sets         Yes,            
     Variable*            `collation_server'        
     *Variable Name*      `collation_server'        
     *Variable Scope*     Global,         
                          Session         
     *Dynamic Variable*   Yes             
                          *Permitted        
                          Values          
                          *               
     *Type*               `string'        


     Use COLLATION_NAME as the default server collation. See *Note
     charset-configuration::.

   *  `--console'

     Options for console      *Command-Line        `--console'        
     Format*                              
     *Option-File Format* `console'        
     *Platform Specific*  windows         


     (Windows only.) Write error log messages to `stderr' and `stdout'
     even if `--log-error' is specified.  *Note `mysqld': mysqld. does
     not close the console window if this option is used.

   *  `--core-file'

     Options for core-file      *Command-Line        `--core-file'        
     Format*                              
     *Option-File Format* `core-file'        
                          *Permitted        
                          Values          
                          *               
     *Type*               `boolean'        
     *Default*            `FALSE'         


     Write a core file if *Note `mysqld': mysqld. dies. The name and
     location of the core file is system dependent. On Linux, a core
     file named `core.PID' is written to the current working directory
     of the process, which for *Note `mysqld': mysqld. is the data
     directory.  PID represents the process ID of the server process.
     On Mac OS X, a core file named `core.PID' is written to the
     `/cores' directory. On Solaris, use the `coreadm' command to
     specify where to write the core file and how to name it.

     For some systems, to get a core file you must also specify the
     `--core-file-size' option to *Note `mysqld_safe': mysqld-safe. See
     *Note mysqld-safe::. On some systems, such as Solaris, you do not
     get a core file if you are also using the `--user' option. There
     might be additional restrictions or limitations. For example, it
     might be necessary to execute `ulimit -c unlimited' before
     starting the server. Consult your system documentation.

   *  `--datadir=PATH', `-h PATH'

     Options for datadir      *Command-Line        `--datadir=path'        
     Format*                              
     **                   `-h'            
     *Option-File Format* `datadir'        
     *Option Sets         Yes,            
     Variable*            `datadir'        
     *Variable Name*      `datadir'        
     *Variable Scope*     Global          
     *Dynamic Variable*   No              
                          *Permitted        
                          Values          
                          *               
     *Type*               `file           
                          name'           


     The path to the data directory.

   *  `--debug[=DEBUG_OPTIONS]', `-# [DEBUG_OPTIONS]'

     Options for debug      *Command-Line        `--debug[=debug_options]'        
     Format*                              
     *Option-File Format* `debug'         
     *Variable Name*      `debug'         
     *Variable Scope*     Global,         
                          Session         
     *Dynamic Variable*   Yes             
                          *Permitted        
                          Values          
                          *               
     *Type*               `string'        
     *Default*            `'d:t:o,/tmp/mysqld.trace''        


     If MySQL is configured with `--with-debug', you can use this
     option to get a trace file of what *Note `mysqld': mysqld. is
     doing. A typical DEBUG_OPTIONS string is `'d:t:o,FILE_NAME''.  The
     default is `'d:t:i:o,mysqld.trace''. See MySQL Internals: Porting
     (http://forge.mysql.com/wiki/MySQL_Internals_Porting).

     As of MySQL 5.0.25, using `--with-debug' to configure MySQL with
     debugging support enables you to use the
     `--debug="d,parser_debug"' option when you start the server. This
     causes the Bison parser that is used to process SQL statements to
     dump a parser trace to the server's standard error output.
     Typically, this output is written to the error log.

   *  `--default-character-set=CHARSET_NAME'

     Options for default-character-set      *Version Deprecated* 5.0             
     *Command-Line        `--default-character-set=name'        
     Format*                              
     **                   `-C             
                          name'           
     *Option-File Format* `default-character-set=name'        
     *Deprecated*         5.0             
                          *Permitted        
                          Values          
                          *               
     *Type*               `string'        


     Use CHARSET_NAME as the default character set. This option is
     deprecated in favor of `--character-set-server'. See *Note
     charset-configuration::.  `--default-character-set' is removed in
     MySQL 5.5.

   *  `--default-collation=COLLATION_NAME'

     Options for default-collation      *Command-Line        `--default-collation=name'        
     Format*                              
     *Option-File Format* `default-collation=name'        
     *Deprecated*         4.1.3           
                          *Permitted        
                          Values          
                          *               
     *Type*               `string'        


     Use COLLATION_NAME as the default collation. This option is
     deprecated in favor of `--collation-server'. See *Note
     charset-configuration::.  `--default-collation' is removed in
     MySQL 5.5.

   *  `--default-storage-engine=TYPE'

     Options for default-storage-engine      *Command-Line        `--default-storage-engine=name'        
     Format*                              
     *Option-File Format* `default-storage-engine'        
     *Variable Name*      `storage_engine'        
     *Variable Scope*     Global,         
                          Session         
     *Dynamic Variable*   Yes             


     Set the default storage engine (table type) for tables. See *Note
     storage-engines::.

   *  `--default-table-type=TYPE'

     Options for default-table-type      *Version Deprecated* 5.0             
     *Command-Line        `--default-table-type=name'        
     Format*                              
     *Option-File Format* `default-table-type'        
     *Deprecated*         5.0,            
                          by              
                          `default-storage-engine'        
                          *Permitted        
                          Values          
                          *               
     *Type*               `string'        


     This option is a deprecated synonym for `--default-storage-engine'.

   *  `--default-time-zone=TIMEZONE'

     Options for default-time-zone      *Command-Line        `--default-time-zone=name'        
     Format*                              
     *Option-File Format* `default-time-zone'        
                          *Permitted        
                          Values          
                          *               
     *Type*               `string'        


     Set the default server time zone. This option sets the global
     `time_zone' system variable. If this option is not given, the
     default time zone is the same as the system time zone (given by
     the value of the `system_time_zone' system variable.

   *  `--delay-key-write[={OFF|ON|ALL}]'

     Options for delay-key-write      *Command-Line        `--delay-key-write[=name]'        
     Format*                              
     *Option-File Format* `delay-key-write'        
     *Option Sets         Yes,            
     Variable*            `delay_key_write'        
     *Variable Name*      `delay-key-write'        
     *Variable Scope*     Global          
     *Dynamic Variable*   Yes             
                          *Permitted        
                          Values          
                          *               
     *Type*               `enumeration'        
     *Default*            `ON'            
     *Valid Values*       `ON'            
                          `OFF'           
                          `ALL'           


     Specify how to use delayed key writes. Delayed key writing causes
     key buffers not to be flushed between writes for `MyISAM' tables.
     `OFF' disables delayed key writes. `ON' enables delayed key writes
     for those tables that were created with the `DELAY_KEY_WRITE'
     option.  `ALL' delays key writes for all `MyISAM' tables. See
     *Note server-parameters::, and *Note myisam-start::.

     *Note*:

     If you set this variable to `ALL', you should not use `MyISAM'
     tables from within another program (such as another MySQL server or
     *Note `myisamchk': myisamchk.) when the tables are in use.  Doing
     so leads to index corruption.

   *  `--des-key-file=FILE_NAME'

     Options for des-key-file      *Command-Line        `--des-key-file=file_name'        
     Format*                              
     *Option-File Format* `des-key-file=file_name'        


     Read the default DES keys from this file. These keys are used by
     the `DES_ENCRYPT()' and `DES_DECRYPT()' functions.

   *  `--enable-named-pipe'

     Options for enable-named-pipe      *Command-Line        `--enable-named-pipe'        
     Format*                              
     *Option-File Format* `enable-named-pipe'        
     *Option Sets         Yes,            
     Variable*            `named_pipe'        
     *Platform Specific*  windows         


     Enable support for named pipes. This option can be used only with
     the *Note `mysqld-nt': mysqld. and *Note `mysqld-debug': mysqld.
     servers that support named-pipe connections.

   *  `--enable-pstack'

     Options for enable-pstack      *Command-Line        `--enable-pstack'        
     Format*                              
     *Option-File Format* `enable-pstack'        
     *Deprecated*         5.1.54          
                          *Permitted        
                          Values          
                          *               
     *Type*               `boolean'        
     *Default*            `FALSE'         


     Print a symbolic stack trace on failure. This capability is
     available only on Intel Linux systems, and only if MySQL was
     configured with the `--with-pstack' option.

   *  `--engine-condition-pushdown={ON|OFF}'

     Options for engine-condition-pushdown      *Version Introduced* 5.0.3           
     *Command-Line        `--engine-condition-pushdown'        
     Format*                              
     *Option-File Format* `engine-condition-pushdown'        
     *Option Sets         Yes,            
     Variable*            `engine_condition_pushdown'        
     *Variable Name*      `engine_condition_pushdown'        
     *Variable Scope*     Global,         
                          Session         
     *Dynamic Variable*   Yes             
     *Deprecated*         5.5.3,          
                          by              
                          `optimizer_switch'        
                          *Permitted        
                          Values          
                          (>=             
                          5.0.3)*         
     *Type*               `boolean'        
     *Default*            `OFF'           


     Sets the `engine_condition_pushdown' system variable. For more
     information, see *Note condition-pushdown-optimization::.

     This variable was added in MySQL 5.0.3.

   *  `--exit-info[=FLAGS]', `-T [FLAGS]'

     Options for exit-info      *Command-Line        `--exit-info[=flags]'        
     Format*                              
     **                   `-T             
                          [flags]'        
     *Option-File Format* `exit-info'        
                          *Permitted        
                          Values          
                          *               
     *Type*               `numeric'        


     This is a bit mask of different flags that you can use for
     debugging the *Note `mysqld': mysqld. server. Do not use this
     option unless you know _exactly_ what it does!

   *  `--external-locking'

     Options for external-locking      *Command-Line        `--external-locking'        
     Format*                              
     *Option-File Format* `external-locking'        
     *Option Sets         Yes,            
     Variable*            `skip_external_locking'        
     *Disabled by*        `skip-external-locking'        
                          *Permitted        
                          Values          
                          *               
     *Type*               `boolean'        
     *Default*            `FALSE'         


     Enable external locking (system locking), which is disabled by
     default as of MySQL 4.0. Note that if you use this option on a
     system on which `lockd' does not fully work (such as Linux), it is
     easy for *Note `mysqld': mysqld. to deadlock. This option
     previously was named `--enable-locking'.

     External locking affects only *Note `MyISAM':
     myisam-storage-engine. table access. For more information,
     including conditions under which it can and cannot be used, see
     *Note external-locking::.

   *  `--flush'

     Options for flush      *Command-Line        `--flush'        
     Format*                              
     *Option-File Format* `flush'         
     *Variable Name*      `flush'         
     *Variable Scope*     Global          
     *Dynamic Variable*   Yes             
                          *Permitted        
                          Values          
                          *               
     *Type*               `boolean'        
     *Default*            `OFF'           


     Flush (synchronize) all changes to disk after each SQL statement.
     Normally, MySQL does a write of all changes to disk only after
     each SQL statement and lets the operating system handle the
     synchronizing to disk. See *Note crashing::.

   *  `--gdb'

     Options for gdb      *Command-Line        `--gdb'         
     Format*                              
     *Option-File Format* `gdb'           
                          *Permitted        
                          Values          
                          *               
     *Type*               `boolean'        
     *Default*            `FALSE'         


     Install an interrupt handler for `SIGINT' (needed to stop *Note
     `mysqld': mysqld. with `^C' to set breakpoints) and disable stack
     tracing and core file handling. See MySQL Internals: Porting
     (http://forge.mysql.com/wiki/MySQL_Internals_Porting).

   *  `--init-file=FILE_NAME'

     Options for init-file      *Command-Line        `--init-file=file_name'        
     Format*                              
     *Option-File Format* `init-file=file_name'        
     *Option Sets         Yes,            
     Variable*            `init_file'        
     *Variable Name*      `init_file'        
     *Variable Scope*     Global          
     *Dynamic Variable*   No              
                          *Permitted        
                          Values          
                          *               
     *Type*               `file           
                          name'           


     Read SQL statements from this file at startup. Each statement must
     be on a single line and should not include comments.

     This option is unavailable if MySQL was configured with the
     `--disable-grant-options' option. See *Note
     source-configuration-options::.

   *  `--innodb-safe-binlog'

     Options for innodb-safe-binlog      *Version Removed*    5.0.3           
     *Version Deprecated* 5.0.3           
     *Command-Line        `--innodb-safe-binlog'        
     Format*                              
     *Option-File Format* `innodb-safe-binlog'        
     *Deprecated*         5.0.3           
                          *Permitted        
                          Values          
                          *               
     *Type*               `boolean'        


     If this option is given, then after a crash recovery by `InnoDB',
     *Note `mysqld': mysqld. truncates the binary log after the last
     not-rolled-back transaction in the log. The option also causes
     `InnoDB' to print an error if the binary log is smaller or shorter
     than it should be. See *Note binary-log::. This option was removed
     in MySQL 5.0.3, having been made obsolete by the introduction of
     XA transaction support.

   * `--innodb-XXX'

     The `InnoDB' options are listed in *Note innodb-parameters::.

   *  `--install [SERVICE_NAME]'

     Options for install      *Command-Line        `--install        
     Format*              [service_name]'        


     (Windows only) Install the server as a Windows service that starts
     automatically during Windows startup. The default service name is
     `MySQL' if no SERVICE_NAME value is given. For more information,
     see *Note windows-start-service::.

   *  `--install-manual [SERVICE_NAME]'

     Options for install-manual      *Command-Line        `--install-manual        
     Format*              [service_name]'        


     (Windows only) Install the server as a Windows service that must
     be started manually. It does not start automatically during
     Windows startup. The default service name is `MySQL' if no
     SERVICE_NAME value is given. For more information, see *Note
     windows-start-service::.

   *  `--language=LANG_NAME, -L LANG_NAME'

     Options for language      *Command-Line        `--language=name'        
     Format*                              
     **                   `-L'            
     *Option-File Format* `language'        
     *Option Sets         Yes,            
     Variable*            `language'        
     *Variable Name*      `language'        
     *Variable Scope*     Global          
     *Dynamic Variable*   No              
     *Deprecated*         5.6.1           
                          *Permitted        
                          Values          
                          *               
     *Type*               `directory        
                          name'           
     *Default*            `/usr/local/mysql/share/mysql/english/'        


     The language to use for error messages.  LANG_NAME can be given as
     the language name or as the full path name to the directory where
     the language files are installed. See *Note
     error-message-language::.

   *  `--large-pages'

     Options for large-pages      *Version Introduced* 5.0.3           
     *Command-Line        `--large-pages'        
     Format*                              
     *Option-File Format* `large-pages'        
     *Option Sets         Yes,            
     Variable*            `large_pages'        
     *Variable Name*      `large_pages'        
     *Variable Scope*     Global          
     *Dynamic Variable*   No              
     *Platform Specific*  linux           
                          *Permitted        
                          Values          
                          *               
     *Type* (linux)       `boolean'        
     *Default*            `FALSE'         


     Some hardware/operating system architectures support memory pages
     greater than the default (usually 4KB). The actual implementation
     of this support depends on the underlying hardware and operating
     system. Applications that perform a lot of memory accesses may
     obtain performance improvements by using large pages due to
     reduced Translation Lookaside Buffer (TLB) misses.

     Currently, MySQL supports only the Linux implementation of large
     page support (which is called HugeTLB in Linux). See *Note
     large-page-support::.

     `--large-pages' is disabled by default. It was added in MySQL
     5.0.3.

   *  `--log[=FILE_NAME]', `-l [FILE_NAME]'

     Options for log      *Command-Line        `--log[=name]'        
     Format*                              
     **                   `-l'            
     *Option-File Format* `log'           
     *Option Sets         Yes,            
     Variable*            `log'           
     *Variable Name*      `log'           
     *Variable Scope*     Global          
     *Dynamic Variable*   No              
     *Deprecated*         5.1.29,         
                          by              
                          `general-log'        
                          *Permitted        
                          Values          
                          *               
     *Type*               `string'        
     *Default*            `OFF'           


     Log connections and SQL statements received from clients to this
     file. See *Note query-log::. If you omit the file name, MySQL uses
     `HOST_NAME.log' as the file name.

   *  `--log-error[=FILE_NAME]'

     Options for log-error      *Command-Line        `--log-error[=name]'        
     Format*                              
     *Option-File Format* `log-error'        
     *Option Sets         Yes,            
     Variable*            `log_error'        
     *Variable Name*      `log_error'        
     *Variable Scope*     Global          
     *Dynamic Variable*   No              
                          *Permitted        
                          Values          
                          *               
     *Type*               `file           
                          name'           


     Log errors and startup messages to this file. See *Note
     error-log::. If you omit the file name, MySQL uses `HOST_NAME.err'.
     If the file name has no extension, the server adds an extension of
     `.err'.

   *  `--log-isam[=FILE_NAME]'

     Options for log-isam      *Command-Line        `--log-isam[=name]'        
     Format*                              
     *Option-File Format* `log-isam'        
                          *Permitted        
                          Values          
                          *               
     *Type*               `file           
                          name'           


     Log all `MyISAM' changes to this file (used only when debugging
     `MyISAM').

   *  `--log-long-format'

     Options for log-long-format      *Command-Line        `--log-long-format'        
     Format*                              
     **                   `-0'            
     *Option-File Format* `log-long-format'        
     *Deprecated*         4.1             


     Log extra information to the update log, binary update log, and
     slow query log, if they have been activated. For example, the user
     name and timestamp are logged for all queries. This option is
     deprecated, as it now represents the default logging behavior.
     (See the description for `--log-short-format'.) The
     `--log-queries-not-using-indexes' option is available for the
     purpose of logging queries that do not use indexes to the slow
     query log.  `--log-long-format' is removed in MySQL 5.5.

   *  `--log-queries-not-using-indexes'

     Options for log-queries-not-using-indexes      *Command-Line        `--log-queries-not-using-indexes'        
     Format*                              
     *Option-File Format* `log-queries-not-using-indexes'        
     *Option Sets         Yes,            
     Variable*            `log_queries_not_using_indexes'        
     *Variable Name*      `log_queries_not_using_indexes'        
     *Variable Scope*     Global          
     *Dynamic Variable*   Yes             
                          *Permitted        
                          Values          
                          *               
     *Type*               `boolean'        
     *Default*            `OFF'           


     If you are using this option with the slow query log enabled,
     queries that are expected to retrieve all rows are logged. See
     *Note slow-query-log::. This option does not necessarily mean that
     no index is used. For example, a query that uses a full index scan
     uses an index but would be logged because the index would not
     limit the number of rows.

   *  `--log-short-format'

     Options for log-short-format      *Command-Line        `--log-short-format'        
     Format*                              
     *Option-File Format* `log-short-format'        
                          *Permitted        
                          Values          
                          *               
     *Type*               `boolean'        
     *Default*            `FALSE'         


     Originally intended to log less information to the update log,
     binary log and slow query log, if they have been activated.
     However, this option is not operational.

   *  `--log-slow-admin-statements'

     Options for log-slow-admin-statements      *Command-Line        `--log-slow-admin-statements'        
     Format*                              
     *Option-File Format* `log-slow-admin-statements'        
                          *Permitted        
                          Values          
                          *               
     *Type*               `boolean'        
     *Default*            `FALSE'         


     Log slow administrative statements such as *Note `OPTIMIZE TABLE':
     optimize-table, *Note `ANALYZE TABLE': analyze-table, and *Note
     `ALTER TABLE': alter-table. to the slow query log.

   *  `--log-slow-queries[=FILE_NAME]'

     Options for log-slow-queries      *Command-Line        `--log-slow-queries[=name]'        
     Format*                              
     *Option-File Format* `log-slow-queries'        
     *Option Sets         Yes,            
     Variable*            `log_slow_queries'        
     *Variable Name*      `log_slow_queries'        
     *Variable Scope*     Global          
     *Dynamic Variable*   No              
     *Deprecated*         5.1.29,         
                          by              
                          `slow-query-log'        
                          *Permitted        
                          Values          
                          *               
     *Type*               `boolean'        


     Log all queries that have taken more than `long_query_time'
     seconds to execute to this file. See *Note slow-query-log::.  See
     the descriptions of the `--log-long-format' and
     `--log-short-format' options for details.

   *  `--log-tc=FILE_NAME'

     Options for log-tc      *Version Introduced* 5.0.3           
     *Command-Line        `--log-tc=name'        
     Format*                              
     *Option-File Format* `log-tc'        
                          *Permitted        
                          Values          
                          *               
     *Type*               `file           
                          name'           
     *Default*            `tc.log'        


     The name of the memory-mapped transaction coordinator log file
     (for XA transactions that affect multiple storage engines when the
     binary log is disabled). The default name is `tc.log'. The file is
     created under the data directory if not given as a full path name.
     Currently, this option is unused. Added in MySQL 5.0.3.

   *  `--log-tc-size=SIZE'

     Options for log-tc-size      *Version Introduced* 5.0.3           
     *Command-Line        `--log-tc-size=#'        
     Format*                              
     *Option-File Format* `log-tc-size'        
                          *Permitted        
                          Values          
                          *               
     *Platform Bit Size*  `32'            
     *Type*               `numeric'        
     *Default*            `24576'         
     *Max Value*          `4294967295'        
                          *Permitted        
                          Values          
                          *               
     *Platform Bit Size*  `64'            
     *Type*               `numeric'        
     *Default*            `24576'         
     *Max Value*          `18446744073709547520'        


     The size in bytes of the memory-mapped transaction coordinator
     log. The default size is 24KB. Added in MySQL 5.0.3.

   *  `--log-warnings[=LEVEL]', `-W [LEVEL]'

     Options for log-warnings      *Command-Line        `--log-warnings[=#]'        
     Format*                              
     **                   `-W             
                          [#]'            
     *Option-File Format* `log-warnings'        
     *Option Sets         Yes,            
     Variable*            `log_warnings'        
     *Variable Name*      `log_warnings'        
     *Variable Scope*     Global,         
                          Session         
     *Dynamic Variable*   Yes             
     *Disabled by*        `skip-log-warnings'        
                          *Permitted        
                          Values          
                          *               
     *Platform Bit Size*  `64'            
     *Type*               `numeric'        
     *Default*            `1'             
     *Range*              `0 ..           
                          18446744073709547520'        


     Print out warnings such as `Aborted connection...' to the error
     log. Enabling this option is recommended, for example, if you use
     replication (you get more information about what is happening,
     such as messages about network failures and reconnections). This
     option is enabled (1) by default, and the default LEVEL value if
     omitted is 1. To disable this option, use `--log-warnings=0'. If
     the value is greater than 1, aborted connections are written to the
     error log. See *Note communication-errors::.

     If a slave server was started with `--log-warnings' enabled, the
     slave prints messages to the error log to provide information
     about its status, such as the binary log and relay log coordinates
     where it starts its job, when it is switching to another relay
     log, when it reconnects after a disconnect, and so forth.

   *  `--low-priority-updates'

     Options for low-priority-updates      *Command-Line        `--low-priority-updates'        
     Format*                              
     *Option-File Format* `low-priority-updates'        
     *Option Sets         Yes,            
     Variable*            `low_priority_updates'        
     *Variable Name*      `low_priority_updates'        
     *Variable Scope*     Global,         
                          Session         
     *Dynamic Variable*   Yes             
                          *Permitted        
                          Values          
                          *               
     *Type*               `boolean'        
     *Default*            `FALSE'         


     Give table-modifying operations (*Note `INSERT': insert, *Note
     `REPLACE': replace, *Note `DELETE': delete, *Note `UPDATE':
     update.) lower priority than selects. This can also be done using
     `{INSERT | REPLACE | DELETE | UPDATE} LOW_PRIORITY ...' to lower
     the priority of only one query, or by `SET LOW_PRIORITY_UPDATES=1'
     to change the priority in one thread. This affects only storage
     engines that use only table-level locking (`MyISAM', `MEMORY',
     `MERGE'). See *Note table-locking::.

   *  `--memlock'

     Options for memlock      *Command-Line        `--memlock'        
     Format*                              
     *Option-File Format* `memlock'        
     *Variable Name*      `locked_in_memory'        
     *Variable Scope*     Global          
     *Dynamic Variable*   No              
                          *Permitted        
                          Values          
                          *               
     *Type*               `boolean'        
     *Default*            `FALSE'         


     Lock the *Note `mysqld': mysqld. process in memory. This option
     might help if you have a problem where the operating system is
     causing *Note `mysqld': mysqld. to swap to disk.

     `--memlock' works on systems that support the `mlockall()' system
     call; this includes Solaris as well as most Linux distributions
     that use a 2.4 or newer kernel. On Linux systems, you can tell
     whether or not `mlockall()' (and thus this option) is supported by
     checking to see whether or not it is defined in the system
     `mman.h' file, like this:

          shell> grep mlockall /usr/include/sys/mman.h

     If `mlockall()' is supported, you should see in the output of the
     previous command something like the following:

          extern int mlockall (int __flags) __THROW;

     *Important*:

     Using this option requires that you run the server as `root',
     which, for reasons of security, is normally not a good idea. See
     *Note changing-mysql-user::.

     You must not try to use this option on a system that does not
     support the `mlockall()' system call; if you do so, *Note
     `mysqld': mysqld. will very likely crash as soon as you try to
     start it.

   *  `--myisam-block-size=N'

     Options for myisam-block-size      *Command-Line        `--myisam-block-size=#'        
     Format*                              
     *Option-File Format* `myisam-block-size'        
                          *Permitted        
                          Values          
                          *               
     *Type*               `numeric'        
     *Default*            `1024'          
     *Range*              `1024           
                          ..              
                          16384'          


     The block size to be used for `MyISAM' index pages.

   *  `--myisam-recover[=OPTION[,OPTION]...]]'

     Options for myisam-recover      *Command-Line        `--myisam-recover[=name]'        
     Format*                              
     *Option-File Format* `myisam-recover'        
     *Option Sets         Yes,            
     Variable*            `myisam_recover_options'        
                          *Permitted        
                          Values          
                          *               
     *Type*               `enumeration'        
     *Default*            `OFF'           
     *Valid Values*       `DEFAULT'        
                          `BACKUP'        
                          `FORCE'         
                          `QUICK'         


     Set the `MyISAM' storage engine recovery mode. The option value is
     any combination of the values of `DEFAULT', `BACKUP', `FORCE', or
     `QUICK'. If you specify multiple values, separate them by commas.
     Specifying the option with no argument is the same as specifying
     `DEFAULT', and specifying with an explicit value of `""' disables
     recovery (same as not giving the option). If recovery is enabled,
     each time *Note `mysqld': mysqld. opens a `MyISAM' table, it
     checks whether the table is marked as crashed or was not closed
     properly. (The last option works only if you are running with
     external locking disabled.) If this is the case, *Note `mysqld':
     mysqld. runs a check on the table. If the table was corrupted,
     *Note `mysqld': mysqld. attempts to repair it.

     The following options affect how the repair works.

     Option     Description
     `DEFAULT'  Recovery without backup, forcing, or quick
                checking.
     `BACKUP'   If the data file was changed during recovery,
                save a backup of the `TBL_NAME.MYD' file as
                `TBL_NAME-DATETIME.BAK'.
     `FORCE'    Run recovery even if we would lose more than
                one row from the `.MYD' file.
     `QUICK'    Do not check the rows in the table if there
                are not any delete blocks.

     Before the server automatically repairs a table, it writes a note
     about the repair to the error log. If you want to be able to
     recover from most problems without user intervention, you should
     use the options `BACKUP,FORCE'. This forces a repair of a table
     even if some rows would be deleted, but it keeps the old data file
     as a backup so that you can later examine what happened.

     See *Note myisam-start::.

   *  `--old-passwords'

     Options for old-passwords      *Command-Line        `--old_passwords'        
     Format*                              
     *Option-File Format* `old-passwords'        
     *Option Sets         Yes,            
     Variable*            `old_passwords'        
     *Variable Name*      `old_passwords'        
     *Variable Scope*     Global,         
                          Session         
     *Dynamic Variable*   Yes             
                          *Permitted        
                          Values          
                          *               
     *Type*               `boolean'        
     *Default*            `FALSE'         


     Force the server to generate short (pre-4.1) password hashes for
     new passwords. This is useful for compatibility when the server
     must support older client programs. See *Note password-hashing::.

   *  `--old-style-user-limits'

     Options for old-style-user-limits      *Version Introduced* 5.0.3           
     *Command-Line        `--old-style-user-limits'        
     Format*                              
     *Option-File Format* `old-style-user-limits'        
                          *Permitted        
                          Values          
                          *               
     *Type*               `boolean'        
     *Default*            `FALSE'         


     Enable old-style user limits. (Before MySQL 5.0.3, account
     resource limits were counted separately for each host from which a
     user connected rather than per account row in the `user' table.)
     See *Note user-resources::. This option was added in MySQL 5.0.3.

   *  `--one-thread'

     Options for one-thread      *Command-Line        `--one-thread'        
     Format*                              
     *Option-File Format* `one-thread'        


     Only use one thread (for debugging under Linux). This option is
     available only if the server is built with debugging enabled. See
     MySQL Internals: Porting
     (http://forge.mysql.com/wiki/MySQL_Internals_Porting).

   *  `--open-files-limit=COUNT'

     Options for open-files-limit      *Command-Line        `--open-files-limit=#'        
     Format*                              
     *Option-File Format* `open-files-limit'        
     *Option Sets         Yes,            
     Variable*            `open_files_limit'        
     *Variable Name*      `open_files_limit'        
     *Variable Scope*     Global          
     *Dynamic Variable*   No              
                          *Permitted        
                          Values          
                          *               
     *Type*               `numeric'        
     *Default*            `0'             
     *Range*              `0 ..           
                          65535'          


     Changes the number of file descriptors available to *Note
     `mysqld': mysqld. You should try increasing the value of this
     option if *Note `mysqld': mysqld. gives you the error `Too many
     open files'.  *Note `mysqld': mysqld. uses the option value to
     reserve descriptors with `setrlimit()'. If the requested number of
     file descriptors cannot be allocated, *Note `mysqld': mysqld.
     writes a warning to the error log.

     *Note `mysqld': mysqld. may attempt to allocate more than the
     requested number of descriptors (if they are available), using the
     values of `max_connections' and `table_cache' to estimate whether
     more descriptors will be needed.

   *  `--pid-file=PATH'

     Options for pid-file      *Command-Line        `--pid-file=file_name'        
     Format*                              
     *Option-File Format* `pid-file=file_name'        
     *Option Sets         Yes,            
     Variable*            `pid_file'        
     *Variable Name*      `pid_file'        
     *Variable Scope*     Global          
     *Dynamic Variable*   No              
                          *Permitted        
                          Values          
                          *               
     *Type*               `file           
                          name'           


     The path name of the process ID file. The server creates the file
     in the data directory unless an absolute path name is given to
     specify a different directory. This file is used by other programs
     such as *Note `mysqld_safe': mysqld-safe. to determine the
     server's process ID.

   *  `--port=PORT_NUM', `-P PORT_NUM'

     Options for port      *Command-Line        `--port=#'        
     Format*                              
     **                   `-P'            
     *Option-File Format* `port'          
     *Option Sets         Yes,            
     Variable*            `port'          
     *Variable Name*      `port'          
     *Variable Scope*     Global          
     *Dynamic Variable*   No              
                          *Permitted        
                          Values          
                          *               
     *Type*               `numeric'        
     *Default*            `3306'          


     The port number to use when listening for TCP/IP connections.  The
     port number must be 1024 or higher unless the server is started by
     the `root' system user.

   *  `--port-open-timeout=NUM'

     Options for port-open-timeout      *Version Introduced* 5.0.19          
     *Command-Line        `--port-open-timeout=#'        
     Format*                              
     *Option-File Format* `port-open-timeout'        
                          *Permitted        
                          Values          
                          *               
     *Type*               `numeric'        
     *Default*            `0'             


     On some systems, when the server is stopped, the TCP/IP port might
     not become available immediately. If the server is restarted
     quickly afterward, its attempt to reopen the port can fail. This
     option indicates how many seconds the server should wait for the
     TCP/IP port to become free if it cannot be opened. The default is
     not to wait. This option was added in MySQL 5.0.19.

   *  `--remove [SERVICE_NAME]'

     Options for remove      *Command-Line        `--remove        
     Format*              [service_name]'        


     (Windows only) Remove a MySQL Windows service. The default service
     name is `MySQL' if no SERVICE_NAME value is given. For more
     information, see *Note windows-start-service::.

   *  `--safe-mode'

     Options for safe-mode      *Version Deprecated* 5.0             
     *Command-Line        `--safe-mode'        
     Format*                              
     *Option-File Format* `safe-mode'        
     *Deprecated*         5.0             


     Skip some optimization stages.

   *  `--safe-show-database'

     Options for safe-show-database      *Command-Line        `--safe-show-database'(until  
     Format*                      4.1.1)  
     *Option-File Format* `safe-show-database'        
     *Variable Name*      `safe_show_database'        
     *Variable Scope*     Global          
     *Dynamic Variable*   Yes             
     *Deprecated*         4.0.2           
                          *Permitted        
                          Values          
                          *               
     *Type*               `boolean'        


     This option is deprecated and does not do anything because there
     is a *Note `SHOW DATABASES': show-databases.  privilege that can
     be used to control access to database names on a per-account
     basis. See *Note privileges-provided::.  `--safe-show-database' is
     removed in MySQL 5.5.

   *  `--safe-user-create'

     Options for safe-user-create      *Command-Line        `--safe-user-create'        
     Format*                              
     *Option-File Format* `safe-user-create'        
                          *Permitted        
                          Values          
                          *               
     *Type*               `boolean'        
     *Default*            `FALSE'         


     If this option is enabled, a user cannot create new MySQL users by
     using the *Note `GRANT': grant.  statement unless the user has the
     `INSERT' privilege for the `mysql.user' table or any column in the
     table. If you want a user to have the ability to create new users
     that have those privileges that the user has the right to grant,
     you should grant the user the following privilege:

          GRANT INSERT(user) ON mysql.user TO 'USER_NAME'@'HOST_NAME';

     This ensures that the user cannot change any privilege columns
     directly, but has to use the *Note `GRANT': grant. statement to
     give privileges to other users.

   *  `--secure-auth'

     Options for secure-auth      *Command-Line        `--secure-auth'        
     Format*                              
     *Option-File Format* `secure-auth'        
     *Option Sets         Yes,            
     Variable*            `secure_auth'        
     *Variable Name*      `secure_auth'        
     *Variable Scope*     Global          
     *Dynamic Variable*   Yes             
                          *Permitted        
                          Values          
                          *               
     *Type*               `boolean'        
     *Default*            `FALSE'         


     Disallow authentication by clients that attempt to use accounts
     that have old (pre-4.1) passwords.

   *  `--secure-file-priv=PATH'

     Options for secure-file-priv      *Version Introduced* 5.0.38          
     *Command-Line        `--secure-file-priv=path'        
     Format*                              
     *Option-File Format* `secure-file-priv=path'        
     *Option Sets         Yes,            
     Variable*            `secure_file_priv'        
     *Variable Name*      `secure-file-priv'        
     *Variable Scope*     Global          
     *Dynamic Variable*   No              
                          *Permitted        
                          Values          
                          *               
     *Type*               `string'        


     This option limits the effect of the `LOAD_FILE()' function and the
     *Note `LOAD DATA': load-data. and *Note `SELECT ... INTO OUTFILE':
     select-into. statements to work only with files in the specified
     directory.

     This option was added in MySQL 5.0.38.

   *  `--shared-memory'

     Enable shared-memory connections by local clients. This option is
     available only on Windows.

   *  `--shared-memory-base-name=NAME'

     The name of shared memory to use for shared-memory connections.
     This option is available only on Windows. The default name is
     `MYSQL'. The name is case sensitive.

   *  `--skip-bdb'

     Disable the `BDB' storage engine. This saves memory and might
     speed up some operations. Do not use this option if you require
     `BDB' tables.

   *  `--skip-concurrent-insert'

     Turn off the ability to select and insert at the same time on
     `MyISAM' tables. (This is to be used only if you think you have
     found a bug in this feature.) See *Note concurrent-inserts::.

   *  `--skip-external-locking'

     Do not use external locking (system locking). This affects only
     *Note `MyISAM': myisam-storage-engine. table access. For more
     information, including conditions under which it can and cannot be
     used, see *Note external-locking::.

     External locking has been disabled by default since MySQL 4.0.

   *  `--skip-grant-tables'

     This option causes the server to start without using the privilege
     system at all, which gives anyone with access to the server
     _unrestricted access to all databases_. You can cause a running
     server to start using the grant tables again by executing *Note
     `mysqladmin flush-privileges': mysqladmin. or *Note `mysqladmin
     reload': mysqladmin. command from a system shell, or by issuing a
     MySQL *Note `FLUSH PRIVILEGES': flush. statement after connecting
     to the server.  This option also suppresses loading of
     user-defined functions (UDFs).

     This option is unavailable if MySQL was configured with the
     `--disable-grant-options' option. See *Note
     source-configuration-options::.

   *  `--skip-host-cache'

     Do not use the internal host name cache for faster name-to-IP
     resolution. Instead, query the DNS server every time a client
     connects. See *Note dns::.

   * `--skip-innodb'

     Disable the `InnoDB' storage engine. In this case, the server will
     not start if the default storage engine is set to *Note `InnoDB':
     innodb-storage-engine. Use `--default-storage-engine' to set the
     default to some other engine if necessary.

   *  `--skip-merge'

     Disable the `MERGE' storage engine. This option was added in MySQL
     5.0.24. It can be used if the following behavior is undesirable:
     If a user has access to `MyISAM' table T, that user can create a
     `MERGE' table M that accesses T. However, if the user's privileges
     on T are subsequently revoked, the user can continue to access T
     by doing so through M.

   *  `--skip-name-resolve'

     Do not resolve host names when checking client connections.  Use
     only IP addresses. If you use this option, all `Host' column
     values in the grant tables must be IP addresses or `localhost'. See
     *Note dns::.

   *  `--skip-networking'

     Do not listen for TCP/IP connections at all. All interaction with
     *Note `mysqld': mysqld. must be made using named pipes or shared
     memory (on Windows) or Unix socket files (on Unix).  This option
     is highly recommended for systems where only local clients are
     permitted. See *Note dns::.

   * `--ssl*'

     Options that begin with `--ssl' specify whether to permit clients
     to connect using SSL and indicate where to find SSL keys and
     certificates. See *Note ssl-options::.

   *  `--standalone'

     Options for standalone      *Command-Line        `--standalone'        
     Format*                              
     *Option-File Format* `standalone'        
     *Platform Specific*  windows         


     Instructs the MySQL server not to run as a service.

   *  `--symbolic-links', `--skip-symbolic-links'

     Options for symbolic-links      *Command-Line        `--symbolic-links'        
     Format*                              
     *Option-File Format* `symbolic-links'        


     Enable or disable symbolic link support. This option has different
     effects on Windows and Unix:

        * On Windows, enabling symbolic links enables you to establish
          a symbolic link to a database directory by creating a
          `DB_NAME.sym' file that contains the path to the real
          directory. See *Note windows-symbolic-links::.

        * On Unix, enabling symbolic links means that you can link a
          `MyISAM' index file or data file to another directory with
          the `INDEX DIRECTORY' or `DATA DIRECTORY' options of the
          *Note `CREATE TABLE': create-table.  statement. If you delete
          or rename the table, the files that its symbolic links point
          to also are deleted or renamed. See *Note
          symbolic-links-to-tables::.

   *  `--skip-safemalloc'

     Options for skip-safemalloc      *Command-Line        `--skip-safemalloc'        
     Format*                              
     *Option-File Format* `skip-safemalloc'        


     If MySQL is configured with `--with-debug=full', all MySQL
     programs check for memory overruns during each memory allocation
     and memory freeing operation. This checking is very slow, so for
     the server you can avoid it when you do not need it by using the
     `--skip-safemalloc' option.

   *  `--skip-show-database'

     Options for skip-show-database      *Command-Line        `--skip-show-database'        
     Format*                              
     *Option-File Format* `skip-show-database'        
     *Option Sets         Yes,            
     Variable*            `skip_show_database'        
     *Variable Name*      `skip_show_database'        
     *Variable Scope*     Global          
     *Dynamic Variable*   No              


     With this option, the *Note `SHOW DATABASES': show-databases.
     statement is permitted only to users who have the `SHOW DATABASES'
     privilege, and the statement displays all database names.  Without
     this option, *Note `SHOW DATABASES': show-databases. is permitted
     to all users, but displays each database name only if the user has
     the `SHOW DATABASES' privilege or some privilege for the database.
     Note that _any_ global privilege is considered a privilege for the
     database.

   *  `--skip-stack-trace'

     Options for skip-stack-trace      *Command-Line        `--skip-stack-trace'        
     Format*                              
     *Option-File Format* `skip-stack-trace'        


     Do not write stack traces. This option is useful when you are
     running *Note `mysqld': mysqld. under a debugger. On some systems,
     you also must use this option to get a core file. See MySQL
     Internals: Porting
     (http://forge.mysql.com/wiki/MySQL_Internals_Porting).

   *  `--skip-thread-priority'

     Options for skip-thread-priority      *Command-Line        `--skip-thread-priority'        
     Format*                              
     *Option-File Format* `skip-thread-priority'        
     *Deprecated*         5.1.29          


     Disable using thread priorities for faster response time.

     *Note `mysqld': mysqld. makes a large number of invalid calls to
     thread scheduling routines on Linux. These calls do not affect
     performance noticeably but may be a source of `noise' for
     debugging tools. For example, they can overwhelm other information
     of more interest in kernel logs. To avoid these calls, start the
     server with the `--skip-thread-priority' option.

   *  `--socket=PATH'

     Options for socket      *Command-Line        `--socket=name'        
     Format*                              
     *Option-File Format* `socket'        
     *Option Sets         Yes,            
     Variable*            `socket'        
     *Variable Name*      `socket'        
     *Variable Scope*     Global          
     *Dynamic Variable*   No              
                          *Permitted        
                          Values          
                          *               
     *Type*               `file           
                          name'           
     *Default*            `/tmp/mysql.sock'        


     On Unix, this option specifies the Unix socket file to use when
     listening for local connections. The default value is
     `/tmp/mysql.sock'. If this option is given, the server creates the
     file in the data directory unless an absolute path name is given
     to specify a different directory.  On Windows, the option
     specifies the pipe name to use when listening for local
     connections that use a named pipe. The default value is `MySQL'
     (not case sensitive).

   *  `--sql-mode=VALUE[,VALUE[,VALUE...]]'

     Options for sql-mode      *Command-Line        `--sql-mode=name'        
     Format*                              
     *Option-File Format* `sql-mode'        
     *Option Sets         Yes,            
     Variable*            `sql_mode'        
     *Variable Name*      `sql_mode'        
     *Variable Scope*     Global,         
                          Session         
     *Dynamic Variable*   Yes             
                          *Permitted        
                          Values          
                          *               
     *Type*               `set'           
     *Default*            `'''            
     *Valid Values*       `ALLOW_INVALID_DATES'        
                          `ANSI_QUOTES'        
                          `ERROR_FOR_DIVISION_BY_ZERO'        
                          `HIGH_NOT_PRECEDENCE'        
                          `IGNORE_SPACE'        
                          `NO_AUTO_CREATE_USER'        
                          `NO_AUTO_VALUE_ON_ZERO'        
                          `NO_BACKSLASH_ESCAPES'        
                          `NO_DIR_IN_CREATE'        
                          `NO_ENGINE_SUBSTITUTION'        
                          `NO_FIELD_OPTIONS'        
                          `NO_KEY_OPTIONS'        
                          `NO_TABLE_OPTIONS'        
                          `NO_UNSIGNED_SUBTRACTION'        
                          `NO_ZERO_DATE'        
                          `NO_ZERO_IN_DATE'        
                          `ONLY_FULL_GROUP_BY'        
                          `PAD_CHAR_TO_FULL_LENGTH'        
                          `PIPES_AS_CONCAT'        
                          `REAL_AS_FLOAT'        
                          `STRICT_ALL_TABLES'        
                          `STRICT_TRANS_TABLES'        


     Set the SQL mode. See *Note server-sql-mode::.

   *  `--sysdate-is-now'

     Options for sysdate-is-now      *Version Introduced* 5.0.20          
     *Command-Line        `--sysdate-is-now'        
     Format*                              
     *Option-File Format* `sysdate-is-now'        
                          *Permitted        
                          Values          
                          *               
     *Type*               `boolean'        
     *Default*            `FALSE'         


     As of MySQL 5.0.12, `SYSDATE()' by default returns the time at
     which it executes, not the time at which the statement in which it
     occurs begins executing.  This differs from the behavior of
     `NOW()'. This option causes `SYSDATE()' to be an alias for
     `NOW()'. For information about the implications for binary logging
     and replication, see the description for `SYSDATE()' in *Note
     date-and-time-functions:: and for `SET TIMESTAMP' in *Note
     server-system-variables::.

     This option was added in MySQL 5.0.20.

   *  `--tc-heuristic-recover={COMMIT|ROLLBACK}'

     Options for tc-heuristic-recover      *Version Introduced* 5.0.3           
     *Command-Line        `--tc-heuristic-recover=name'        
     Format*                              
     *Option-File Format* `tc-heuristic-recover'        
                          *Permitted        
                          Values          
                          *               
     *Type*               `enumeration'        
     *Valid Values*       `COMMIT'        
                          `RECOVER'        


     The type of decision to use in the heuristic recovery process.
     Currently, this option is unused. Added in MySQL 5.0.3.

   *  `--temp-pool'

     Options for temp-pool      *Command-Line        `--temp-pool'        
     Format*                              
     *Option-File Format* `temp-pool'        
                          *Permitted        
                          Values          
                          *               
     *Type*               `boolean'        
     *Default*            `TRUE'          


     This option causes most temporary files created by the server to
     use a small set of names, rather than a unique name for each new
     file. This works around a problem in the Linux kernel dealing with
     creating many new files with different names.  With the old
     behavior, Linux seems to `leak' memory, because it is being
     allocated to the directory entry cache rather than to the disk
     cache.

   *  `--transaction-isolation=LEVEL'

     Options for transaction-isolation      *Command-Line        `--transaction-isolation=name'        
     Format*                              
     *Option-File Format* `transaction-isolation'        
     *Option Sets         Yes,            
     Variable*            `tx_isolation'        
                          *Permitted        
                          Values          
                          *               
     *Type*               `enumeration'        
     *Valid Values*       `READ-UNCOMMITTED'        
                          `READ-COMMITTED'        
                          `REPEATABLE-READ'        
                          `SERIALIZABLE'        


     Sets the default transaction isolation level. The `level' value
     can be `READ-UNCOMMITTED', `READ-COMMITTED', `REPEATABLE-READ', or
     `SERIALIZABLE'. See *Note set-transaction::.

     The default transaction isolation level can also be set in the
     running server using *Note `SET TRANSACTION': set-transaction. or
     by setting the `tx_isolation' system variable.

   *  `--tmpdir=PATH', `-t PATH'

     Options for tmpdir      *Command-Line        `--tmpdir=path'        
     Format*                              
     **                   `-t'            
     *Option-File Format* `tmpdir'        
     *Option Sets         Yes,            
     Variable*            `tmpdir'        
     *Variable Name*      `tmpdir'        
     *Variable Scope*     Global          
     *Dynamic Variable*   No              
                          *Permitted        
                          Values          
                          *               
     *Type*               `file           
                          name'           


     The path of the directory to use for creating temporary files.  It
     might be useful if your default `/tmp' directory resides on a
     partition that is too small to hold temporary tables. This option
     accepts several paths that are used in round-robin fashion. Paths
     should be separated by colon characters (``:'') on Unix and
     semicolon characters (``;'') on Windows, NetWare, and OS/2. If the
     MySQL server is acting as a replication slave, you should not set
     `--tmpdir' to point to a directory on a memory-based file system
     or to a directory that is cleared when the server host restarts.
     For more information about the storage location of temporary
     files, see *Note temporary-files::. A replication slave needs some
     of its temporary files to survive a machine restart so that it can
     replicate temporary tables or *Note `LOAD DATA INFILE': load-data.
     operations. If files in the temporary file directory are lost when
     the server restarts, replication fails.

   *  `--user={USER_NAME|USER_ID}', `-u {USER_NAME|USER_ID}'

     Options for user      *Command-Line        `--user=name'        
     Format*                              
     **                   `-u             
                          name'           
     *Option-File Format* `user'          
                          *Permitted        
                          Values          
                          *               
     *Type*               `string'        


     Run the *Note `mysqld': mysqld. server as the user having the name
     USER_NAME or the numeric user ID USER_ID.  (`User' in this context
     refers to a system login account, not a MySQL user listed in the
     grant tables.)

     This option is _mandatory_ when starting *Note `mysqld': mysqld.
     as `root'. The server changes its user ID during its startup
     sequence, causing it to run as that particular user rather than as
     `root'. See *Note security-guidelines::.

     To avoid a possible security hole where a user adds a
     `--user=root' option to a `my.cnf' file (thus causing the server to
     run as `root'), *Note `mysqld': mysqld.  uses only the first
     `--user' option specified and produces a warning if there are
     multiple `--user' options. Options in `/etc/my.cnf' and
     `$MYSQL_HOME/my.cnf' are processed before command-line options, so
     it is recommended that you put a `--user' option in `/etc/my.cnf'
     and specify a value other than `root'. The option in `/etc/my.cnf'
     is found before any other `--user' options, which ensures that the
     server runs as a user other than `root', and that a warning
     results if any other `--user' option is found.

   *  `--verbose', `-v'

     Use this option with the `--help' option for detailed help.

   *  `--version', `-V'

     Options for version      *Variable Name*      `version'        
     *Variable Scope*     Global          
     *Dynamic Variable*   No              


     Display version information and exit.

You can assign a value to a server system variable by using an option
of the form `--VAR_NAME=VALUE'.  For example, `--key_buffer_size=32M'
sets the `key_buffer_size' variable to a value of 32MB.

Note that when you assign a value to a variable, MySQL might
automatically correct the value to stay within a given range, or adjust
the value to the closest permissible value if only certain values are
permitted.

If you want to restrict the maximum value to which a variable can be
set at runtime with *Note `SET': set-option, you can define this by
using the `--maximum-VAR_NAME=VALUE' command-line option.

It is also possible to set variables by using
`--set-variable=VAR_NAME=VALUE' or `-O VAR_NAME=VALUE' syntax. _This
syntax is deprecated_.

You can change the values of most system variables for a running server
with the *Note `SET': set-option.  statement. See *Note set-option::.

*Note server-system-variables::, provides a full description for all
variables, and additional information for setting them at server
startup and runtime.  *Note server-parameters::, includes information on
optimizing the server by tuning system variables.


File: manual.info,  Node: server-system-variables,  Next: using-system-variables,  Prev: server-options,  Up: mysqld-server

6.1.3 Server System Variables
-----------------------------

The MySQL server maintains many system variables that indicate how it
is configured. Each system variable has a default value. System
variables can be set at server startup using options on the command
line or in an option file. Most of them can be changed dynamically
while the server is running by means of the *Note `SET': set-option.
statement, which enables you to modify operation of the server without
having to stop and restart it. You can refer to system variable values
in expressions.

There are several ways to see the names and values of system variables:

   * To see the values that a server will use based on its compiled-in
     defaults and any option files that it reads, use this command:

          mysqld --verbose --help

   * To see the values that a server will use based on its compiled-in
     defaults, ignoring the settings in any option files, use this
     command:

          mysqld --no-defaults --verbose --help

   * To see the current values used by a running server, use the *Note
     `SHOW VARIABLES': show-variables. statement.

This section provides a description of each system variable.  Variables
with no version indicated are present in all MySQL 5.0 releases. For
historical information concerning their implementation, please see
http://www.mysql.com/products/enterprise//4.1/en/.

The following table lists all available system variables:

*System Variable Summary*

Name           Cmd-Line    Option file System Var  Var Scope   Dynamic
auto_increment_incrementYes         Yes         Yes         Both        Yes
auto_increment_offsetYes         Yes         Yes         Both        Yes
autocommit     Yes         Yes         Yes         Session     Yes
automatic_sp_privileges                        Yes         Global      Yes
back_log       Yes         Yes         Yes         Global      No
basedir        Yes         Yes         Yes         Global      No
bdb_cache_size Yes         Yes         Yes         Global      No
bdb-home       Yes         Yes                                 No
- _Variable_:                          Yes         Global      No
bdb_home                                                       
bdb-lock-detectYes         Yes                                 No
- _Variable_:                          Yes         Global      No
bdb_lock_detect                                                
bdb_log_buffer_sizeYes         Yes         Yes         Global      No
bdb-logdir     Yes         Yes                                 No
- _Variable_:                          Yes         Global      No
bdb_logdir                                                     
bdb_max_lock   Yes         Yes         Yes         Global      No
bdb-shared-dataYes         Yes                                 No
- _Variable_:                          Yes         Global      No
bdb_shared_data                                                
bdb-tmpdir     Yes         Yes                                 No
- _Variable_:                          Yes         Global      No
bdb_tmpdir                                                     
big-tables     Yes         Yes                                 Yes
- _Variable_:                          Yes         Session     Yes
big_tables                                                     
bind-address   Yes         Yes         Yes         Global      No
binlog_cache_sizeYes         Yes         Yes         Global      Yes
bulk_insert_buffer_sizeYes         Yes         Yes         Both        Yes
character_set_client                        Yes         Both        Yes
character_set_connection                        Yes         Both        Yes
character_set_database                        Yes         Both        Yes
This option                                                    
is dynamic,                                                    
but only the                                                   
server should                                                  
set this                                                       
information.                                                   
You should                                                     
not set the                                                    
value of this                                                  
variable                                                       
manually.                                                      
character-set-filesystemYes         Yes                                 Yes
- _Variable_:                          Yes         Both        Yes
character_set_filesystem                                                
character_set_results                        Yes         Both        Yes
character-set-serverYes         Yes                                 Yes
- _Variable_:                          Yes         Both        Yes
character_set_server                                                
character_set_system                        Yes         Global      No
character-sets-dirYes         Yes                                 No
- _Variable_:                          Yes         Global      No
character_sets_dir                                                
collation_connection                        Yes         Both        Yes
collation_database                        Yes         Both        Yes
This option                                                    
is dynamic,                                                    
but only the                                                   
server should                                                  
set this                                                       
information.                                                   
You should                                                     
not set the                                                    
value of this                                                  
variable                                                       
manually.                                                      
collation-serverYes         Yes                                 Yes
- _Variable_:                          Yes         Both        Yes
collation_server                                                
completion_typeYes         Yes         Yes         Both        Yes
concurrent_insertYes         Yes         Yes         Global      Yes
connect_timeoutYes         Yes         Yes         Global      Yes
datadir        Yes         Yes         Yes         Global      No
date_format                            Yes         Both        No
datetime_format                        Yes         Both        No
debug          Yes         Yes         Yes         Both        Yes
default-storage-engineYes         Yes         Yes         Both        Yes
default_week_formatYes         Yes         Yes         Both        Yes
delay-key-writeYes         Yes                                 Yes
- _Variable_:                          Yes         Global      Yes
delay_key_write                                                
delayed_insert_limitYes         Yes         Yes         Global      Yes
delayed_insert_timeoutYes         Yes         Yes         Global      Yes
delayed_queue_sizeYes         Yes         Yes         Global      Yes
div_precision_incrementYes         Yes         Yes         Both        Yes
engine-condition-pushdownYes         Yes                                 Yes
- _Variable_:                          Yes         Both        Yes
engine_condition_pushdown                                                
error_count                            Yes         Session     No
expire_logs_daysYes         Yes         Yes         Global      Yes
flush          Yes         Yes         Yes         Global      Yes
flush_time     Yes         Yes         Yes         Global      Yes
foreign_key_checks                        Yes         Session     Yes
ft_boolean_syntaxYes         Yes         Yes         Global      Yes
ft_max_word_lenYes         Yes         Yes         Global      No
ft_min_word_lenYes         Yes         Yes         Global      No
ft_query_expansion_limitYes         Yes         Yes         Global      No
ft_stopword_fileYes         Yes         Yes         Global      No
group_concat_max_lenYes         Yes         Yes         Both        Yes
have_archive                           Yes         Global      No
have_bdb                               Yes         Global      No
have_blackhole_engine                        Yes         Global      No
have_compress                          Yes         Global      No
have_crypt                             Yes         Global      No
have_csv                               Yes         Global      No
have_example_engine                        Yes         Global      No
have_federated_engine                        Yes         Global      No
have_geometry                          Yes         Global      No
have_innodb                            Yes         Global      No
have_isam                              Yes         Global      No
have_merge_engine                        Yes         Global      No
have_ndbcluster                        Yes         Global      No
have_openssl                           Yes         Global      No
have_query_cache                        Yes         Global      No
have_raid                              Yes         Global      No
have_rtree_keys                        Yes         Global      No
have_ssl                               Yes         Global      No
have_symlink                           Yes         Global      No
hostname                               Yes         Global      No
identity                               Yes         Session     Yes
init_connect   Yes         Yes         Yes         Global      Yes
init-file      Yes         Yes                                 No
- _Variable_:                          Yes         Global      No
init_file                                                      
init_slave     Yes         Yes         Yes         Global      Yes
innodb_adaptive_hash_indexYes         Yes         Yes         Global      No
innodb_additional_mem_pool_sizeYes         Yes         Yes         Global      No
innodb_autoextend_incrementYes         Yes         Yes         Global      Yes
innodb_buffer_pool_awe_mem_mbYes         Yes         Yes         Global      No
innodb_buffer_pool_sizeYes         Yes         Yes         Global      No
innodb_checksumsYes         Yes         Yes         Global      No
innodb_commit_concurrencyYes         Yes         Yes         Global      Yes
innodb_concurrency_ticketsYes         Yes         Yes         Global      Yes
innodb_data_file_pathYes         Yes         Yes         Global      No
innodb_data_home_dirYes         Yes         Yes         Global      No
innodb_doublewriteYes         Yes         Yes         Global      No
innodb_fast_shutdownYes         Yes         Yes         Global      Yes
innodb_file_io_threadsYes         Yes         Yes         Global      No
innodb_file_per_tableYes         Yes         Yes         Global      No
innodb_flush_log_at_trx_commitYes         Yes         Yes         Global      Yes
innodb_flush_methodYes         Yes         Yes         Global      No
innodb_force_recoveryYes         Yes         Yes         Global      No
innodb_lock_wait_timeoutYes         Yes         Yes         Global      No
innodb_locks_unsafe_for_binlogYes         Yes         Yes         Global      No
innodb_log_arch_dirYes         Yes         Yes         Global      No
innodb_log_archiveYes         Yes         Yes         Global      No
innodb_log_buffer_sizeYes         Yes         Yes         Global      No
innodb_log_file_sizeYes         Yes         Yes         Global      No
innodb_log_files_in_groupYes         Yes         Yes         Global      No
innodb_log_group_home_dirYes         Yes         Yes         Global      No
innodb_max_dirty_pages_pctYes         Yes         Yes         Global      Yes
innodb_max_purge_lagYes         Yes         Yes         Global      Yes
innodb_mirrored_log_groupsYes         Yes         Yes         Global      No
innodb_open_filesYes         Yes         Yes         Global      No
innodb_rollback_on_timeoutYes         Yes         Yes         Global      No
innodb-status-fileYes         Yes         Yes         Global      No
innodb_support_xaYes         Yes         Yes         Both        Yes
innodb_sync_spin_loopsYes         Yes         Yes         Global      Yes
innodb_table_locksYes         Yes         Yes         Both        Yes
innodb_thread_concurrencyYes         Yes         Yes         Global      Yes
innodb_thread_sleep_delayYes         Yes         Yes         Global      Yes
innodb_use_legacy_cardinality_algorithmYes         Yes         Yes         Global      Yes
insert_id                              Yes         Session     Yes
interactive_timeoutYes         Yes         Yes         Both        Yes
join_buffer_sizeYes         Yes         Yes         Both        Yes
keep_files_on_createYes         Yes         Yes         Both        Yes
key_buffer_sizeYes         Yes         Yes         Global      Yes
key_cache_age_thresholdYes         Yes         Yes         Global      Yes
key_cache_block_sizeYes         Yes         Yes         Global      Yes
key_cache_division_limitYes         Yes         Yes         Global      Yes
language       Yes         Yes         Yes         Global      No
large_files_support                        Yes         Global      No
large_page_size                        Yes         Global      No
large-pages    Yes         Yes                                 No
- _Variable_:                          Yes         Global      No
large_pages                                                    
last_insert_id                         Yes         Session     Yes
lc_time_names                          Yes         Both        Yes
license                                Yes         Global      No
local_infile                           Yes         Global      Yes
locked_in_memory                        Yes         Global      No
log            Yes         Yes         Yes         Global      No
log_bin                                Yes         Global      No
log-bin        Yes         Yes         Yes         Global      No
log-bin-trust-function-creatorsYes         Yes                                 Yes
- _Variable_:                          Yes         Global      Yes
log_bin_trust_function_creators                                                
log-bin-trust-routine-creatorsYes         Yes                                 Yes
- _Variable_:                          Yes         Global      Yes
log_bin_trust_routine_creators                                                
log-error      Yes         Yes                                 No
- _Variable_:                          Yes         Global      No
log_error                                                      
log-queries-not-using-indexesYes         Yes                                 Yes
- _Variable_:                          Yes         Global      Yes
log_queries_not_using_indexes                                                
log-slave-updatesYes         Yes                                 No
- _Variable_:                          Yes         Global      No
log_slave_updates                                                
log-slow-queriesYes         Yes                                 No
- _Variable_:                          Yes         Global      No
log_slow_queries                                                
log-warnings   Yes         Yes                                 Yes
- _Variable_:                          Yes         Both        Yes
log_warnings                                                   
long_query_timeYes         Yes         Yes         Both        Yes
low-priority-updatesYes         Yes                                 Yes
- _Variable_:                          Yes         Both        Yes
low_priority_updates                                                
lower_case_file_systemYes         Yes         Yes         Global      No
lower_case_table_namesYes         Yes         Yes         Global      No
max_allowed_packetYes         Yes         Yes         Global      Yes
max_binlog_cache_sizeYes         Yes         Yes         Global      Yes
max_binlog_sizeYes         Yes         Yes         Global      Yes
max_connect_errorsYes         Yes         Yes         Global      Yes
max_connectionsYes         Yes         Yes         Global      Yes
max_delayed_threadsYes         Yes         Yes         Both        Yes
max_error_countYes         Yes         Yes         Both        Yes
max_heap_table_sizeYes         Yes         Yes         Both        Yes
max_insert_delayed_threads                        Yes         Both        Yes
max_join_size  Yes         Yes         Yes         Both        Yes
max_length_for_sort_dataYes         Yes         Yes         Both        Yes
max_prepared_stmt_countYes         Yes         Yes         Global      Yes
max_relay_log_sizeYes         Yes         Yes         Global      Yes
max_seeks_for_keyYes         Yes         Yes         Both        Yes
max_sort_lengthYes         Yes         Yes         Both        Yes
max_sp_recursion_depthYes         Yes         Yes         Both        Yes
max_tmp_tables Yes         Yes         Yes         Both        Yes
max_user_connectionsYes         Yes         Yes         Both        Yes
max_write_lock_countYes         Yes         Yes         Global      Yes
memlock        Yes         Yes         Yes         Global      No
multi_range_countYes         Yes         Yes         Both        Yes
myisam_data_pointer_sizeYes         Yes         Yes         Global      Yes
myisam_max_extra_sort_file_sizeYes         Yes         Yes         Global      No
myisam_max_sort_file_sizeYes         Yes         Yes         Global      Yes
myisam_mmap_sizeYes         Yes         Yes         Global      No
myisam_recover_options                        Yes         Global      No
myisam_repair_threadsYes         Yes         Yes         Both        Yes
myisam_sort_buffer_sizeYes         Yes         Yes         Both        Yes
myisam_stats_methodYes         Yes         Yes         Both        Yes
named_pipe                             Yes         Global      No
ndb_autoincrement_prefetch_szYes         Yes         Yes         Both        Yes
ndb_cache_check_timeYes         Yes         Yes         Global      Yes
ndb_force_send Yes         Yes         Yes         Both        Yes
ndb_use_exact_count                        Yes         Both        Yes
ndb_use_transactionsYes         Yes         Yes         Both        Yes
net_buffer_lengthYes         Yes         Yes         Both        Yes
net_read_timeoutYes         Yes         Yes         Both        Yes
net_retry_countYes         Yes         Yes         Both        Yes
net_write_timeoutYes         Yes         Yes         Both        Yes
new            Yes         Yes         Yes         Both        Yes
old-passwords  Yes         Yes                                 Yes
- _Variable_:                          Yes         Both        Yes
old_passwords                                                  
open-files-limitYes         Yes                                 No
- _Variable_:                          Yes         Global      No
open_files_limit                                                
optimizer_prune_levelYes         Yes         Yes         Both        Yes
optimizer_search_depthYes         Yes         Yes         Both        Yes
pid-file       Yes         Yes                                 No
- _Variable_:                          Yes         Global      No
pid_file                                                       
plugin_dir     Yes         Yes         Yes         Global      No
port           Yes         Yes         Yes         Global      No
preload_buffer_sizeYes         Yes         Yes         Both        Yes
prepared_stmt_count                        Yes         Global      No
profiling                              Yes         Session     Yes
profiling_history_size                        Yes         Both        Yes
protocol_version                        Yes         Global      No
pseudo_thread_id                        Yes         Session     Yes
query_alloc_block_sizeYes         Yes         Yes         Both        Yes
query_cache_limitYes         Yes         Yes         Global      Yes
query_cache_min_res_unitYes         Yes         Yes         Global      Yes
query_cache_sizeYes         Yes         Yes         Global      Yes
query_cache_typeYes         Yes         Yes         Both        Yes
query_cache_wlock_invalidateYes         Yes         Yes         Both        Yes
query_prealloc_sizeYes         Yes         Yes         Both        Yes
rand_seed1                             Yes         Session     Yes
rand_seed2                             Yes         Session     Yes
range_alloc_block_sizeYes         Yes         Yes         Both        Yes
read_buffer_sizeYes         Yes         Yes         Both        Yes
read_only      Yes         Yes         Yes         Global      Yes
read_rnd_buffer_sizeYes         Yes         Yes         Both        Yes
relay-log-indexYes         Yes                                 No
- _Variable_:                          Yes         Both        No
relay_log_index                                                
relay_log_indexYes         Yes         Yes         Global      No
relay_log_info_fileYes         Yes         Yes         Global      No
relay_log_purgeYes         Yes         Yes         Global      Yes
relay_log_space_limitYes         Yes         Yes         Global      No
report-host    Yes         Yes                                 No
- _Variable_:                          Yes         Global      No
report_host                                                    
report-passwordYes         Yes                                 No
- _Variable_:                          Yes         Global      No
report_password                                                
report-port    Yes         Yes                                 No
- _Variable_:                          Yes         Global      No
report_port                                                    
report-user    Yes         Yes                                 No
- _Variable_:                          Yes         Global      No
report_user                                                    
rpl_recovery_rank                        Yes         Global      Yes
safe-show-databaseYes         Yes         Yes         Global      Yes
secure-auth    Yes         Yes                                 Yes
- _Variable_:                          Yes         Global      Yes
secure_auth                                                    
secure-file-privYes         Yes                                 No
- _Variable_:                          Yes         Global      No
secure_file_priv                                                
server-id      Yes         Yes                                 Yes
- _Variable_:                          Yes         Global      Yes
server_id                                                      
shared_memory                          Yes         Global      No
shared_memory_base_name                        Yes         Global      No
skip-external-lockingYes         Yes                                 No
- _Variable_:                          Yes         Global      No
skip_external_locking                                                
skip-name-resolveYes         Yes                                 No
- _Variable_:                          Yes         Global      No
skip_name_resolve                                                
skip-networkingYes         Yes                                 No
- _Variable_:                          Yes         Global      No
skip_networking                                                
skip-show-databaseYes         Yes                                 No
- _Variable_:                          Yes         Global      No
skip_show_database                                                
skip-sync-bdb-logsYes         Yes         Yes         Global      No
slave_compressed_protocolYes         Yes         Yes         Global      Yes
slave-load-tmpdirYes         Yes                                 No
- _Variable_:                          Yes         Global      No
slave_load_tmpdir                                                
slave-net-timeoutYes         Yes                                 Yes
- _Variable_:                          Yes         Global      Yes
slave_net_timeout                                                
slave-skip-errorsYes         Yes                                 No
- _Variable_:                          Yes         Global      No
slave_skip_errors                                                
slave_transaction_retriesYes         Yes         Yes         Global      Yes
slow_launch_timeYes         Yes         Yes         Global      Yes
socket         Yes         Yes         Yes         Global      No
sort_buffer_sizeYes         Yes         Yes         Both        Yes
sql_auto_is_null                        Yes         Session     Yes
sql_big_selects                        Yes         Session     Yes
sql_big_tables                         Yes         Session     Yes
sql_buffer_result                        Yes         Session     Yes
sql_log_bin                            Yes         Session     Yes
sql_log_off                            Yes         Session     Yes
sql_log_update                         Yes         Session     Yes
sql_low_priority_updates                        Yes         Both        Yes
sql_max_join_size                        Yes         Both        Yes
sql-mode       Yes         Yes                                 Yes
- _Variable_:                          Yes         Both        Yes
sql_mode                                                       
sql_notes                              Yes         Session     Yes
sql_quote_show_create                        Yes         Session     Yes
sql_safe_updates                        Yes         Session     Yes
sql_select_limit                        Yes         Both        Yes
sql_slave_skip_counter                        Yes         Global      Yes
sql_warnings                           Yes         Session     Yes
ssl-ca         Yes         Yes                                 No
- _Variable_:                          Yes         Global      No
ssl_ca                                                         
ssl-capath     Yes         Yes                                 No
- _Variable_:                          Yes         Global      No
ssl_capath                                                     
ssl-cert       Yes         Yes                                 No
- _Variable_:                          Yes         Global      No
ssl_cert                                                       
ssl-cipher     Yes         Yes                                 No
- _Variable_:                          Yes         Global      No
ssl_cipher                                                     
ssl-key        Yes         Yes                                 No
- _Variable_:                          Yes         Global      No
ssl_key                                                        
storage_engine                         Yes         Both        Yes
sync-bdb-logs  Yes         Yes                                 No
- _Variable_:                          Yes         Global      No
sync_bdb_logs                                                  
sync_binlog    Yes         Yes         Yes         Global      Yes
sync_frm       Yes         Yes         Yes         Global      Yes
system_time_zone                        Yes         Global      No
table_cache    Yes         Yes         Yes         Global      Yes
table_lock_wait_timeoutYes         Yes         Yes         Global      Yes
table_type                             Yes         Both        Yes
thread_cache_sizeYes         Yes         Yes         Global      Yes
thread_concurrencyYes         Yes         Yes         Global      No
thread_stack   Yes         Yes         Yes         Global      No
time_format                            Yes         Both        No
time_zone      Yes         Yes         Yes         Both        Yes
timed_mutexes  Yes         Yes         Yes         Global      Yes
timestamp                              Yes         Session     Yes
tmp_table_size Yes         Yes         Yes         Both        Yes
tmpdir         Yes         Yes         Yes         Global      No
transaction_alloc_block_sizeYes         Yes         Yes         Both        Yes
transaction_prealloc_sizeYes         Yes         Yes         Both        Yes
tx_isolation                           Yes         Both        Yes
unique_checks                          Yes         Session     Yes
updatable_views_with_limitYes         Yes         Yes         Both        Yes
version                                Yes         Global      No
version_comment                        Yes         Global      No
version_compile_machine                        Yes         Global      No
version_compile_os                        Yes         Global      No
wait_timeout   Yes         Yes         Yes         Both        Yes
warning_count                          Yes         Session     No

For additional system variable information, see these sections:

   * *Note using-system-variables::, discusses the syntax for setting
     and displaying system variable values.

   * *Note dynamic-system-variables::, lists the variables that can be
     set at runtime.

   * Information on tuning system variables can be found in *Note
     server-parameters::.

   * *Note innodb-parameters::, lists `InnoDB' system variables.

   * *Note mysql-cluster-system-variables::, lists system variables
     which are specific to MySQL Cluster.

   * For information on server system variables specific to
     replication, see *Note replication-options::.

*Note*:

Some of the following variable descriptions refer to `enabling' or
`disabling' a variable.  These variables can be enabled with the *Note
`SET': set-option.  statement by setting them to `ON' or `1', or
disabled by setting them to `OFF' or `0'. However, to set such a
variable on the command line or in an option file, you must set it to
`1' or `0'; setting it to `ON' or `OFF' will not work. For example, on
the command line, `--delay_key_write=1' works but
`--delay_key_write=ON' does not.

Some system variables control the size of buffers or caches. For a
given buffer, the server might need to allocate internal data
structures. These structures typically are allocated from the total
memory allocated to the buffer, and the amount of space required might
be platform dependent. This means that when you assign a value to a
system variable that controls a buffer size, the amount of space
actually available might differ from the value assigned. In some cases,
the amount might be less than the value assigned. It is also possible
that the server will adjust a value upward. For example, if you assign
a value of 0 to a variable for which the minimal value is 1024, the
server will set the value to 1024.

Values for buffer sizes, lengths, and stack sizes are given in bytes
unless otherwise specified.

Some system variables take file name values. Unless otherwise
specified, the default file location is the data directory if the value
is a relative path name. To specify the location explicitly, use an
absolute path name. Suppose that the data directory is
`/var/mysql/data'. If a file-valued variable is given as a relative
path name, it will be located under `/var/mysql/data'. If the value is
an absolute path name, its location is as given by the path name.

   *  `autocommit'

     Options for autocommit      *Command-Line        `--autocommit[=#]'        
     Format*                              
     *Option-File Format* `autocommit'        
     *Option Sets         Yes,            
     Variable*            `autocommit'        
     *Variable Name*      `autocommit'        
     *Variable Scope*     Session         
     *Dynamic Variable*   Yes             
                          *Permitted        
                          Values          
                          *               
     *Type*               `boolean'        


     The autocommit mode. If set to 1, all changes to a table take
     effect immediately. If set to 0, you must use *Note `COMMIT':
     commit. to accept a transaction or *Note `ROLLBACK': commit.  to
     cancel it. If `autocommit' is 0 and you change it to 1, MySQL
     performs an automatic *Note `COMMIT': commit. of any open
     transaction.  Another way to begin a transaction is to use a *Note
     `START TRANSACTION': commit. or *Note `BEGIN': commit.  statement.
     See *Note commit::.

     By default, client connections begin with `autocommit' set to 1.
     To cause clients to begin with a default of 0, set the server's
     `init_connect' system variable:

          SET GLOBAL init_connect='SET autocommit=0';

     The `init_connect' variable can also be set on the command line or
     in an option file. To set the variable as just shown using an
     option file, include these lines:

          [mysqld]
          init_connect='SET autocommit=0'

     The content of `init_connect' is not executed for users that have
     the `SUPER' privilege.

   *  `automatic_sp_privileges'

     Options for automatic_sp_privileges      *Version Introduced* 5.0.3           
     *Variable Name*      `automatic_sp_privileges'        
     *Variable Scope*     Global          
     *Dynamic Variable*   Yes             
                          *Permitted        
                          Values          
                          *               
     *Type*               `boolean'        
     *Default*            `TRUE'          


     When this variable has a value of 1 (the default), the server
     automatically grants the `EXECUTE' and `ALTER ROUTINE' privileges
     to the creator of a stored routine, if the user cannot already
     execute and alter or drop the routine. (The `ALTER ROUTINE'
     privilege is required to drop the routine.) The server also
     automatically drops those privileges from the creator when the
     routine is dropped. If `automatic_sp_privileges' is 0, the server
     does not automatically add or drop these privileges.

     The creator of a routine is the account used to execute the
     `CREATE' statement for it. This might not be the same as the
     account named as the `DEFINER' in the routine definition.

     See also *Note stored-routines-privileges::.

     This variable was added in MySQL 5.0.3.

   *  `back_log'

     Options for back_log      *Command-Line        `--back_log=#'        
     Format*                              
     *Option-File Format* `back_log'        
     *Option Sets         Yes,            
     Variable*            `back_log'        
     *Variable Name*      `back_log'        
     *Variable Scope*     Global          
     *Dynamic Variable*   No              
                          *Permitted        
                          Values          
                          *               
     *Type*               `numeric'        
     *Default*            `50'            
     *Range*              `1 ..           
                          65535'          


     The number of outstanding connection requests MySQL can have.
     This comes into play when the main MySQL thread gets very many
     connection requests in a very short time. It then takes some time
     (although very little) for the main thread to check the connection
     and start a new thread. The `back_log' value indicates how many
     requests can be stacked during this short time before MySQL
     momentarily stops answering new requests. You need to increase
     this only if you expect a large number of connections in a short
     period of time.

     In other words, this value is the size of the listen queue for
     incoming TCP/IP connections. Your operating system has its own
     limit on the size of this queue. The manual page for the Unix
     `listen()' system call should have more details. Check your OS
     documentation for the maximum value for this variable. `back_log'
     cannot be set higher than your operating system limit.

   *  `basedir'

     Options for basedir      *Command-Line        `--basedir=path'        
     Format*                              
     **                   `-b'            
     *Option-File Format* `basedir'        
     *Option Sets         Yes,            
     Variable*            `basedir'        
     *Variable Name*      `basedir'        
     *Variable Scope*     Global          
     *Dynamic Variable*   No              
                          *Permitted        
                          Values          
                          *               
     *Type*               `file           
                          name'           


     The MySQL installation base directory. This variable can be set
     with the `--basedir' option.  Relative path names for other
     variables usually are resolved relative to the base directory.

   *  `bdb_cache_size'

     Options for bdb_cache_size      *Command-Line        `--bdb_cache_size=#'        
     Format*                              
     *Option-File Format* `bdb_cache_size'        
     *Option Sets         Yes,            
     Variable*            `bdb_cache_size'        
     *Variable Name*      `bdb_cache_size'        
     *Variable Scope*     Global          
     *Dynamic Variable*   No              
                          *Permitted        
                          Values          
                          *               
     *Type*               `numeric'        
     *Min Value*          `20480          
                          '               


     The size of the buffer that is allocated for caching indexes and
     rows for `BDB' tables. If you do not use `BDB' tables, you should
     start *Note `mysqld': mysqld. with `--skip-bdb' to not allocate
     memory for this cache.

   *  `bdb_home'

     Options for bdb-home      *Command-Line        `--bdb-home=name'        
     Format*                              
     *Option-File Format* `bdb-home=name'        
     *Option Sets         Yes,            
     Variable*            `bdb_home'        
     *Variable Name*      `bdb_home'        
     *Variable Scope*     Global          
     *Dynamic Variable*   No              
                          *Permitted        
                          Values          
                          *               
     *Type*               `file           
                          name'           


     The base directory for `BDB' tables. This should be assigned the
     same value as the `datadir' variable.

   *  `bdb_log_buffer_size'

     Options for bdb_log_buffer_size      *Command-Line        `--bdb_log_buffer_size=#'        
     Format*                              
     *Option-File Format* `bdb_log_buffer_size'        
     *Option Sets         Yes,            
     Variable*            `bdb_log_buffer_size'        
     *Variable Name*      `bdb_log_buffer_size'        
     *Variable Scope*     Global          
     *Dynamic Variable*   No              
                          *Permitted        
                          Values          
                          *               
     *Type*               `numeric'        
     *Range*              `262144         
                          ..              
                          4294967295'        


     The size of the buffer that is allocated for caching indexes and
     rows for `BDB' tables. If you do not use `BDB' tables, you should
     set this to 0 or start *Note `mysqld': mysqld. with `--skip-bdb'
     to not allocate memory for this cache.

   *  `bdb_logdir'

     Options for bdb-logdir      *Command-Line        `--bdb-logdir=file_name'        
     Format*                              
     *Option-File Format* `bdb-logdir=file_name'        
     *Option Sets         Yes,            
     Variable*            `bdb_logdir'        
     *Variable Name*      `bdb_logdir'        
     *Variable Scope*     Global          
     *Dynamic Variable*   No              
                          *Permitted        
                          Values          
                          *               
     *Type*               `file           
                          name'           


     The directory where the `BDB' storage engine writes its log files.
     This variable can be set with the `--bdb-logdir' option.

   *  `bdb_max_lock'

     Options for bdb_max_lock      *Command-Line        `--bdb_max_lock=#'        
     Format*                              
     *Option-File Format* `bdb_max_lock'        
     *Option Sets         Yes,            
     Variable*            `bdb_max_lock'        
     *Variable Name*      `bdb_max_lock'        
     *Variable Scope*     Global          
     *Dynamic Variable*   No              
                          *Permitted        
                          Values          
                          *               
     *Type*               `numeric'        
     *Default*            `10000'         


     The maximum number of locks that can be active for a `BDB' table
     (10,000 by default). You should increase this value if errors such
     as the following occur when you perform long transactions or when
     *Note `mysqld': mysqld. has to examine many rows to calculate a
     query:

          bdb: Lock table is out of available locks
          Got error 12 from ...

   *  `bdb_shared_data'

     Options for bdb-shared-data      *Command-Line        `--bdb-shared-data'        
     Format*                              
     *Option-File Format* `bdb-shared-data'        
     *Option Sets         Yes,            
     Variable*            `bdb_shared_data'        
     *Variable Name*      `bdb-shared-data'        
     *Variable Scope*     Global          
     *Dynamic Variable*   No              


     This is `ON' if you are using `--bdb-shared-data' to start
     Berkeley DB in multi-process mode. (Do not use `DB_PRIVATE' when
     initializing Berkeley DB.)

   *  `bdb_tmpdir'

     Options for bdb-tmpdir      *Command-Line        `--bdb-tmpdir=path'        
     Format*                              
     *Option-File Format* `bdb-tmpdir=path'        
     *Option Sets         Yes,            
     Variable*            `bdb_tmpdir'        
     *Variable Name*      `bdb-tmpdir'        
     *Variable Scope*     Global          
     *Dynamic Variable*   No              
                          *Permitted        
                          Values          
                          *               
     *Type*               `file           
                          name'           


     The `BDB' temporary file directory.

   *  `big_tables'

     If set to 1, all temporary tables are stored on disk rather than
     in memory. This is a little slower, but the error `The table
     TBL_NAME is full' does not occur for *Note `SELECT': select.
     operations that require a large temporary table. The default value
     for a new connection is 0 (use in-memory temporary tables).
     Normally, you should never need to set this variable, because
     in-memory tables are automatically converted to disk-based tables
     as required.

     *Note*:

     This variable was formerly named `sql_big_tables'.

   *  `binlog_cache_size'

     Options for binlog_cache_size      *Command-Line        `--binlog_cache_size=#'        
     Format*                              
     *Option-File Format* `binlog_cache_size'        
     *Option Sets         Yes,            
     Variable*            `binlog_cache_size'        
     *Variable Name*      `binlog_cache_size'        
     *Variable Scope*     Global          
     *Dynamic Variable*   Yes             
                          *Permitted        
                          Values          
                          *               
     *Platform Bit Size*  `32'            
     *Type*               `numeric'        
     *Default*            `32768'         
     *Range*              `4096           
                          ..              
                          4294967295'        
                          *Permitted        
                          Values          
                          *               
     *Platform Bit Size*  `64'            
     *Type*               `numeric'        
     *Default*            `32768'         
     *Range*              `4096           
                          ..              
                          18446744073709547520'        


     The size of the cache to hold the SQL statements for the binary
     log during a transaction. A binary log cache is allocated for each
     client if the server supports any transactional storage engines
     and if the server has the binary log enabled (`--log-bin' option).
     If you often use large, multiple-statement transactions, you can
     increase this cache size to get better performance. The
     `Binlog_cache_use' and `Binlog_cache_disk_use' status variables
     can be useful for tuning the size of this variable.  See *Note
     binary-log::.

   *  `bulk_insert_buffer_size'

     Options for bulk_insert_buffer_size      *Command-Line        `--bulk_insert_buffer_size=#'        
     Format*                              
     *Option-File Format* `bulk_insert_buffer_size'        
     *Option Sets         Yes,            
     Variable*            `bulk_insert_buffer_size'        
     *Variable Name*      `bulk_insert_buffer_size'        
     *Variable Scope*     Global,         
                          Session         
     *Dynamic Variable*   Yes             
                          *Permitted        
                          Values          
                          *               
     *Platform Bit Size*  `32'            
     *Type*               `numeric'        
     *Default*            `8388608'        
     *Range*              `0 ..           
                          4294967295'        
                          *Permitted        
                          Values          
                          *               
     *Platform Bit Size*  `64'            
     *Type*               `numeric'        
     *Default*            `8388608'        
     *Range*              `0 ..           
                          18446744073709547520'        


     `MyISAM' uses a special tree-like cache to make bulk inserts
     faster for *Note `INSERT ... SELECT': insert-select, `INSERT ...
     VALUES (...), (...), ...', and *Note `LOAD DATA INFILE':
     load-data. when adding data to nonempty tables. This variable
     limits the size of the cache tree in bytes per thread. Setting it
     to 0 disables this optimization. The default value is 8MB.

   *  `character_set_client'

     Options for character_set_client      *Variable Name*      `character_set_client'        
     *Variable Scope*     Global,         
                          Session         
     *Dynamic Variable*   Yes             
                          *Permitted        
                          Values          
                          *               
     *Type*               `string'        


     The character set for statements that arrive from the client.  The
     session value of this variable is set using the character set
     requested by the client when the client connects to the server.
     (Many clients support a `--default-character-set' option to enable
     this character set to be specified explicitly. See also *Note
     charset-connection::.) The global value of the variable is used to
     set the session value in cases when the client-requested value is
     unknown or not available, or the server is configured to ignore
     client requests:

        * The client is from a version of MySQL older than MySQL 4.1,
          and thus does not request a character set.

        * The client requests a character set not known to the server.
          For example, a Japanese-enabled client requests `sjis' when
          connecting to a server not configured with `sjis' support.

        * *Note `mysqld': mysqld. was started with the
          `--skip-character-set-client-handshake' option, which causes
          it to ignore client character set configuration. This
          reproduces MySQL 4.0 behavior and is useful should you wish
          to upgrade the server without upgrading all the clients.

     `ucs2' cannot be used as a client character set, which means that
     it also does not work for `SET NAMES' or `SET CHARACTER SET'.

   *  `character_set_connection'

     Options for character_set_connection      *Variable Name*      `character_set_connection'        
     *Variable Scope*     Global,         
                          Session         
     *Dynamic Variable*   Yes             
                          *Permitted        
                          Values          
                          *               
     *Type*               `string'        


     The character set used for literals that do not have a character
     set introducer and for number-to-string conversion.

   *  `character_set_database'

     Options for character_set_database      *Variable Name*      `character_set_database'        
     *Variable Scope*     Global,         
                          Session         
     *Dynamic Variable*   Yes             
     *Footnote*           This            
                          option          
                          is              
                          dynamic,        
                          but             
                          only            
                          the             
                          server          
                          should          
                          set             
                          this            
                          information.        
                          You             
                          should          
                          not             
                          set             
                          the             
                          value           
                          of              
                          this            
                          variable        
                          manually.        
                          *Permitted        
                          Values          
                          *               
     *Type*               `string'        


     The character set used by the default database. The server sets
     this variable whenever the default database changes. If there is
     no default database, the variable has the same value as
     `character_set_server'.

   *  `character_set_filesystem'

     Options for character-set-filesystem      *Version Introduced* 5.0.19          
     *Command-Line        `--character-set-filesystem=name'        
     Format*                              
     *Option-File Format* `character-set-filesystem'        
     *Option Sets         Yes,            
     Variable*            `character_set_filesystem'        
     *Variable Name*      `character_set_filesystem'        
     *Variable Scope*     Global,         
                          Session         
     *Dynamic Variable*   Yes             
                          *Permitted        
                          Values          
                          *               
     *Type*               `string'        


     The file system character set. This variable is used to interpret
     string literals that refer to file names, such as in the *Note
     `LOAD DATA INFILE': load-data. and *Note `SELECT ... INTO
     OUTFILE': select-into. statements and the `LOAD_FILE()' function.
     Such file names are converted from `character_set_client' to
     `character_set_filesystem' before the file opening attempt occurs.
     The default value is `binary', which means that no conversion
     occurs. For systems on which multi-byte file names are permitted,
     a different value may be more appropriate. For example, if the
     system represents file names using UTF-8, set
     `character_set_filesystem' to `'utf8''. This variable was added in
     MySQL 5.0.19.

   *  `character_set_results'

     Options for character_set_results      *Variable Name*      `character_set_results'        
     *Variable Scope*     Global,         
                          Session         
     *Dynamic Variable*   Yes             
                          *Permitted        
                          Values          
                          *               
     *Type*               `string'        


     The character set used for returning query results such as result
     sets or error messages to the client.

   *  `character_set_server'

     Options for character-set-server      *Command-Line        `--character-set-server'        
     Format*                              
     *Option-File Format* `character-set-server'        
     *Option Sets         Yes,            
     Variable*            `character_set_server'        
     *Variable Name*      `character_set_server'        
     *Variable Scope*     Global,         
                          Session         
     *Dynamic Variable*   Yes             
                          *Permitted        
                          Values          
                          *               
     *Type*               `string'        


     The server's default character set.

   *  `character_set_system'

     Options for character_set_system      *Variable Name*      `character_set_system'        
     *Variable Scope*     Global          
     *Dynamic Variable*   No              
                          *Permitted        
                          Values          
                          *               
     *Type*               `string'        


     The character set used by the server for storing identifiers.  The
     value is always `utf8'.

   *  `character_sets_dir'

     Options for character-sets-dir      *Command-Line        `--character-sets-dir=path'        
     Format*                              
     *Option-File Format* `character-sets-dir=path'        
     *Option Sets         Yes,            
     Variable*            `character_sets_dir'        
     *Variable Name*      `character-sets-dir'        
     *Variable Scope*     Global          
     *Dynamic Variable*   No              
                          *Permitted        
                          Values          
                          *               
     *Type*               `directory        
                          name'           


     The directory where character sets are installed.

   *  `collation_connection'

     Options for collation_connection      *Variable Name*      `collation_connection'        
     *Variable Scope*     Global,         
                          Session         
     *Dynamic Variable*   Yes             
                          *Permitted        
                          Values          
                          *               
     *Type*               `string'        


     The collation of the connection character set.

   *  `collation_database'

     Options for collation_database      *Variable Name*      `collation_database'        
     *Variable Scope*     Global,         
                          Session         
     *Dynamic Variable*   Yes             
     *Footnote*           This            
                          option          
                          is              
                          dynamic,        
                          but             
                          only            
                          the             
                          server          
                          should          
                          set             
                          this            
                          information.        
                          You             
                          should          
                          not             
                          set             
                          the             
                          value           
                          of              
                          this            
                          variable        
                          manually.        
                          *Permitted        
                          Values          
                          *               
     *Type*               `string'        


     The collation used by the default database. The server sets this
     variable whenever the default database changes. If there is no
     default database, the variable has the same value as
     `collation_server'.

   *  `collation_server'

     Options for collation-server      *Command-Line        `--collation-server'        
     Format*                              
     *Option-File Format* `collation-server'        
     *Option Sets         Yes,            
     Variable*            `collation_server'        
     *Variable Name*      `collation_server'        
     *Variable Scope*     Global,         
                          Session         
     *Dynamic Variable*   Yes             
                          *Permitted        
                          Values          
                          *               
     *Type*               `string'        


     The server's default collation.

   *  `completion_type'

     Options for completion_type      *Version Introduced* 5.0.3           
     *Command-Line        `--completion_type=#'        
     Format*                              
     *Option-File Format* `completion_type'        
     *Option Sets         Yes,            
     Variable*            `completion_type'        
     *Variable Name*      `completion_type'        
     *Variable Scope*     Global,         
                          Session         
     *Dynamic Variable*   Yes             


     The transaction completion type. This variable can take the values
     shown in the following table.

     Value   Description
     0       *Note `COMMIT': commit. and *Note `ROLLBACK':
             commit.  are unaffected. This is the default
             value.
     1       *Note `COMMIT': commit. and *Note `ROLLBACK':
             commit.  are equivalent to `COMMIT AND CHAIN' and
             `ROLLBACK AND CHAIN', respectively. (A new
             transaction starts immediately with the same
             isolation level as the just-terminated
             transaction.)
     2       *Note `COMMIT': commit. and *Note `ROLLBACK':
             commit.  are equivalent to `COMMIT RELEASE' and
             `ROLLBACK RELEASE', respectively.  (The server
             disconnects after terminating the transaction.)

     `completion_type' affects transactions that begin with *Note
     `START TRANSACTION': commit. or *Note `BEGIN': commit. and end
     with *Note `COMMIT': commit. or *Note `ROLLBACK': commit. It does
     not apply to implicit commits resulting from execution of the
     statements listed in *Note implicit-commit::. It also does not
     apply for *Note `XA COMMIT': xa-statements, *Note `XA ROLLBACK':
     xa-statements, or when `autocommit=1'.

     This variable was added in MySQL 5.0.3.

   *  `concurrent_insert'

     Options for concurrent_insert      *Command-Line        `--concurrent_insert[=#]'        
     Format*                              
     *Option-File Format* `concurrent_insert'        
     *Option Sets         Yes,            
     Variable*            `concurrent_insert'        
     *Variable Name*      `concurrent_insert'        
     *Variable Scope*     Global          
     *Dynamic Variable*   Yes             
                          *Permitted        
                          Values          
                          (<=             
                          5.0.5)*         
     *Type*               `boolean'        
     *Default*            `TRUE'          


     If 1 (the default), MySQL permits *Note `INSERT': insert. and
     *Note `SELECT': select. statements to run concurrently for
     `MyISAM' tables that have no free blocks in the middle of the data
     file. If you start *Note `mysqld': mysqld. with `--skip-new', this
     variable is set to 0.

     In MySQL 5.0.6, this variable was changed to take three integer
     values:

     Value   Description
     0       Disables concurrent inserts
     1       (Default) Enables concurrent insert for `MyISAM'
             tables that do not have holes
     2       Enables concurrent inserts for all `MyISAM'
             tables, even those that have holes. For a table
             with a hole, new rows are inserted at the end of
             the table if it is in use by another thread.
             Otherwise, MySQL acquires a normal write lock and
             inserts the row into the hole.

     See also *Note concurrent-inserts::.

   *  `connect_timeout'

     Options for connect_timeout      *Command-Line        `--connect_timeout=#'        
     Format*                              
     *Option-File Format* `connect_timeout'        
     *Option Sets         Yes,            
     Variable*            `connect_timeout'        
     *Variable Name*      `connect_timeout'        
     *Variable Scope*     Global          
     *Dynamic Variable*   Yes             
                          *Permitted        
                          Values          
                          (<=             
                          5.0.51)*        
     *Type*               `numeric'        
     *Default*            `5'             
     *Min Value*          `2'             
                          *Permitted        
                          Values          
                          (>=             
                          5.0.52)*        
     *Type*               `numeric'        
     *Default*            `10'            


     The number of seconds that the *Note `mysqld': mysqld.  server
     waits for a connect packet before responding with `Bad handshake'.
     The default value is 10 seconds as of MySQL 5.0.52 and 5 seconds
     before that.

     Increasing the `connect_timeout' value might help if clients
     frequently encounter errors of the form `Lost connection to MySQL
     server at 'XXX', system error: ERRNO'.

   *  `datadir'

     Options for datadir      *Command-Line        `--datadir=path'        
     Format*                              
     **                   `-h'            
     *Option-File Format* `datadir'        
     *Option Sets         Yes,            
     Variable*            `datadir'        
     *Variable Name*      `datadir'        
     *Variable Scope*     Global          
     *Dynamic Variable*   No              
                          *Permitted        
                          Values          
                          *               
     *Type*               `file           
                          name'           


     The MySQL data directory. This variable can be set with the
     `--datadir' option.

   *  `date_format'

     This variable is unused.

   *  `datetime_format'

     This variable is unused.

   *  `default_week_format'

     Options for default_week_format      *Command-Line        `--default_week_format=#'        
     Format*                              
     *Option-File Format* `default_week_format'        
     *Option Sets         Yes,            
     Variable*            `default_week_format'        
     *Variable Name*      `default_week_format'        
     *Variable Scope*     Global,         
                          Session         
     *Dynamic Variable*   Yes             
                          *Permitted        
                          Values          
                          *               
     *Type*               `numeric'        
     *Default*            `0'             
     *Range*              `0 ..           
                          7'              


     The default mode value to use for the `WEEK()' function. See *Note
     date-and-time-functions::.

   *  `delay_key_write'

     Options for delay-key-write      *Command-Line        `--delay-key-write[=name]'        
     Format*                              
     *Option-File Format* `delay-key-write'        
     *Option Sets         Yes,            
     Variable*            `delay_key_write'        
     *Variable Name*      `delay-key-write'        
     *Variable Scope*     Global          
     *Dynamic Variable*   Yes             
                          *Permitted        
                          Values          
                          *               
     *Type*               `enumeration'        
     *Default*            `ON'            
     *Valid Values*       `ON'            
                          `OFF'           
                          `ALL'           


     This option applies only to `MyISAM' tables.  It can have one of
     the following values to affect handling of the `DELAY_KEY_WRITE'
     table option that can be used in *Note `CREATE TABLE':
     create-table.  statements.

     Option  Description
     `OFF'   `DELAY_KEY_WRITE' is ignored.
     `ON'    MySQL honors any `DELAY_KEY_WRITE' option
             specified in *Note `CREATE TABLE': create-table.
             statements. This is the default value.
     `ALL'   All new opened tables are treated as if they were
             created with the `DELAY_KEY_WRITE' option enabled.

     If `DELAY_KEY_WRITE' is enabled for a table, the key buffer is not
     flushed for the table on every index update, but only when the
     table is closed. This speeds up writes on keys a lot, but if you
     use this feature, you should add automatic checking of all
     `MyISAM' tables by starting the server with the `--myisam-recover'
     option (for example, `--myisam-recover=BACKUP,FORCE').  See *Note
     server-options::, and *Note myisam-start::.

     *Warning*:

     If you enable external locking with `--external-locking', there is
     no protection against index corruption for tables that use delayed
     key writes.

   *  `delayed_insert_limit'

     Options for delayed_insert_limit      *Command-Line        `--delayed_insert_limit=#'        
     Format*                              
     *Option-File Format* `delayed_insert_limit'        
     *Option Sets         Yes,            
     Variable*            `delayed_insert_limit'        
     *Variable Name*      `delayed_insert_limit'        
     *Variable Scope*     Global          
     *Dynamic Variable*   Yes             
                          *Permitted        
                          Values          
                          *               
     *Platform Bit Size*  `32'            
     *Type*               `numeric'        
     *Default*            `100'           
     *Range*              `1 ..           
                          4294967295'        
                          *Permitted        
                          Values          
                          *               
     *Platform Bit Size*  `64'            
     *Type*               `numeric'        
     *Default*            `100'           
     *Range*              `1 ..           
                          18446744073709547520'        


     After inserting `delayed_insert_limit' delayed rows, the *Note
     `INSERT DELAYED': insert-delayed.  handler thread checks whether
     there are any *Note `SELECT': select. statements pending. If so,
     it permits them to execute before continuing to insert delayed
     rows.

   *  `delayed_insert_timeout'

     Options for delayed_insert_timeout      *Command-Line        `--delayed_insert_timeout=#'        
     Format*                              
     *Option-File Format* `delayed_insert_timeout'        
     *Option Sets         Yes,            
     Variable*            `delayed_insert_timeout'        
     *Variable Name*      `delayed_insert_timeout'        
     *Variable Scope*     Global          
     *Dynamic Variable*   Yes             
                          *Permitted        
                          Values          
                          *               
     *Type*               `numeric'        
     *Default*            `300'           


     How many seconds an *Note `INSERT DELAYED': insert-delayed.
     handler thread should wait for *Note `INSERT': insert. statements
     before terminating.

   *  `delayed_queue_size'

     Options for delayed_queue_size      *Command-Line        `--delayed_queue_size=#'        
     Format*                              
     *Option-File Format* `delayed_queue_size'        
     *Option Sets         Yes,            
     Variable*            `delayed_queue_size'        
     *Variable Name*      `delayed_queue_size'        
     *Variable Scope*     Global          
     *Dynamic Variable*   Yes             
                          *Permitted        
                          Values          
                          *               
     *Platform Bit Size*  `32'            
     *Type*               `numeric'        
     *Default*            `1000'          
     *Range*              `1 ..           
                          4294967295'        
                          *Permitted        
                          Values          
                          *               
     *Platform Bit Size*  `64'            
     *Type*               `numeric'        
     *Default*            `1000'          
     *Range*              `1 ..           
                          18446744073709547520'        


     This is a per-table limit on the number of rows to queue when
     handling *Note `INSERT DELAYED': insert-delayed.  statements. If
     the queue becomes full, any client that issues an *Note `INSERT
     DELAYED': insert-delayed. statement waits until there is room in
     the queue again.

   *  `div_precision_increment'

     Options for div_precision_increment      *Version Introduced* 5.0.6           
     *Command-Line        `--div_precision_increment=#'        
     Format*                              
     *Option-File Format* `div_precision_increment'        
     *Option Sets         Yes,            
     Variable*            `div_precision_increment'        
     *Variable Name*      `div_precision_increment'        
     *Variable Scope*     Global,         
                          Session         
     *Dynamic Variable*   Yes             
                          *Permitted        
                          Values          
                          *               
     *Type*               `numeric'        
     *Default*            `4'             
     *Range*              `0 ..           
                          30'             


     This variable indicates the number of digits by which to increase
     the scale of the result of division operations performed with the
     `/' operator.  The default value is 4. The minimum and maximum
     values are 0 and 30, respectively. The following example
     illustrates the effect of increasing the default value.

          mysql> SELECT 1/7;
          +--------+
          | 1/7    |
          +--------+
          | 0.1429 |
          +--------+
          mysql> SET div_precision_increment = 12;
          mysql> SELECT 1/7;
          +----------------+
          | 1/7            |
          +----------------+
          | 0.142857142857 |
          +----------------+

     This variable was added in MySQL 5.0.6.

   *  `engine_condition_pushdown'

     Options for engine-condition-pushdown      *Command-Line        `--engine-condition-pushdown'        
     Format*                              
     *Option-File Format* `engine-condition-pushdown'        
     *Option Sets         Yes,            
     Variable*            `engine_condition_pushdown'        
     *Variable Name*      `engine_condition_pushdown'        
     *Variable Scope*     Global,         
                          Session         
     *Dynamic Variable*   Yes             
     *Deprecated*         5.5.3,          
                          by              
                          `optimizer_switch'        
                          *Permitted        
                          Values          
                          (>=             
                          5.1.0)*         
     *Type*               `boolean'        
     *Default*            `ON'            


     The engine condition pushdown optimization enables processing for
     certain comparisons to be `pushed down' to the storage engine
     level for more efficient execution. For more information, see
     *Note condition-pushdown-optimization::.

     Engine condition pushdown is used only by the *Note `NDBCLUSTER':
     mysql-cluster. storage engine.  Enabling this optimization on a
     MySQL Server acting as a MySQL Cluster SQL node causes `WHERE'
     conditions on unindexed columns to be evaluated on the cluster's
     data nodes and only the rows that match to be sent back to the SQL
     node that issued the query. This greatly reduces the amount of
     cluster data that must be sent over the network, increasing the
     efficiency with which results are returned.

     The `engine_condition_pushdown' variable controls whether engine
     condition pushdown is enabled. By default, this variable is `OFF'
     (0). Setting it to `ON' (1) enables pushdown.

     This variable was added in MySQL 5.0.3.

   *  `error_count'

     The number of errors that resulted from the last statement that
     generated messages. This variable is read only. See *Note
     show-errors::.

   *  `expire_logs_days'

     Options for expire_logs_days      *Command-Line        `--expire_logs_days=#'        
     Format*                              
     *Option-File Format* `expire_logs_days'        
     *Option Sets         Yes,            
     Variable*            `expire_logs_days'        
     *Variable Name*      `expire_logs_days'        
     *Variable Scope*     Global          
     *Dynamic Variable*   Yes             
                          *Permitted        
                          Values          
                          *               
     *Type*               `numeric'        
     *Default*            `0'             
     *Range*              `0 ..           
                          99'             


     The number of days for automatic binary log file removal. The
     default is 0, which means `no automatic removal.' Possible
     removals happen at startup and when the binary log is flushed. Log
     flushing occurs as indicated in *Note server-logs::.

     To remove binary log files manually, use the *Note `PURGE BINARY
     LOGS': purge-binary-logs. statement.  See *Note
     purge-binary-logs::.

   *  `flush'

     Options for flush      *Command-Line        `--flush'        
     Format*                              
     *Option-File Format* `flush'         
     *Variable Name*      `flush'         
     *Variable Scope*     Global          
     *Dynamic Variable*   Yes             
                          *Permitted        
                          Values          
                          *               
     *Type*               `boolean'        
     *Default*            `OFF'           


     If `ON', the server flushes (synchronizes) all changes to disk
     after each SQL statement. Normally, MySQL does a write of all
     changes to disk only after each SQL statement and lets the
     operating system handle the synchronizing to disk. See *Note
     crashing::. This variable is set to `ON' if you start *Note
     `mysqld': mysqld. with the `--flush' option.

   *  `flush_time'

     Options for flush_time      *Command-Line        `--flush_time=#'        
     Format*                              
     *Option-File Format* `flush_time'        
     *Option Sets         Yes,            
     Variable*            `flush_time'        
     *Variable Name*      `flush_time'        
     *Variable Scope*     Global          
     *Dynamic Variable*   Yes             
                          *Permitted        
                          Values          
                          *               
     *Type*               `numeric'        
     *Default*            `0'             
     *Min Value*          `0'             
                          *Permitted        
                          Values          
                          *               
     *Type* (windows)     `numeric'        
     *Default*            `1800'          
     *Min Value*          `0'             


     If this is set to a nonzero value, all tables are closed every
     `flush_time' seconds to free up resources and synchronize
     unflushed data to disk. This option is best used only on Windows
     9x or Me, or on systems with minimal resources.

   *  `foreign_key_checks'

     If set to 1 (the default), foreign key constraints for `InnoDB'
     tables are checked. If set to 0, they are ignored. Disabling
     foreign key checking can be useful for reloading `InnoDB' tables
     in an order different from that required by their parent/child
     relationships. See *Note innodb-foreign-key-constraints::.

     Setting `foreign_key_checks' to 0 also affects data definition
     statements: *Note `DROP DATABASE': drop-database. drops a database
     even if it contains tables that have foreign keys that are
     referred to by tables outside the database, and *Note `DROP
     TABLE': drop-table. drops tables that have foreign keys that are
     referred to by other tables.

     *Note*:

     Setting `foreign_key_checks' to 1 does not trigger a scan of the
     existing table data.  Therefore, rows added to the table while
     `foreign_key_checks = 0' will not be verified for consistency.

   *  `ft_boolean_syntax'

     Options for ft_boolean_syntax      *Command-Line        `--ft_boolean_syntax=name'        
     Format*                              
     *Option-File Format* `ft_boolean_syntax'        
     *Variable Name*      `ft_boolean_syntax'        
     *Variable Scope*     Global          
     *Dynamic Variable*   Yes             
                          *Permitted        
                          Values          
                          *               
     *Type*               `string'        
     *Default*            `+-><()~*:""&'        


     The list of operators supported by boolean full-text searches
     performed using `IN BOOLEAN MODE'. See *Note fulltext-boolean::.

     The default variable value is `'+ -><()~*:""&|''. The rules for
     changing the value are as follows:

        * Operator function is determined by position within the string.

        * The replacement value must be 14 characters.

        * Each character must be an ASCII nonalphanumeric character.

        * Either the first or second character must be a space.

        * No duplicates are permitted except the phrase quoting
          operators in positions 11 and 12. These two characters are
          not required to be the same, but they are the only two that
          may be.

        * Positions 10, 13, and 14 (which by default are set to ``:'',
          ``&'', and ``|'') are reserved for future extensions.

   *  `ft_max_word_len'

     Options for ft_max_word_len      *Command-Line        `--ft_max_word_len=#'        
     Format*                              
     *Option-File Format* `ft_max_word_len'        
     *Option Sets         Yes,            
     Variable*            `ft_max_word_len'        
     *Variable Name*      `ft_max_word_len'        
     *Variable Scope*     Global          
     *Dynamic Variable*   No              
                          *Permitted        
                          Values          
                          *               
     *Type*               `numeric'        
     *Min Value*          `10'            


     The maximum length of the word to be included in a `FULLTEXT'
     index.

     *Note*:

     `FULLTEXT' indexes must be rebuilt after changing this variable.
     Use `REPAIR TABLE TBL_NAME QUICK'.

   *  `ft_min_word_len'

     Options for ft_min_word_len      *Command-Line        `--ft_min_word_len=#'        
     Format*                              
     *Option-File Format* `ft_min_word_len'        
     *Option Sets         Yes,            
     Variable*            `ft_min_word_len'        
     *Variable Name*      `ft_min_word_len'        
     *Variable Scope*     Global          
     *Dynamic Variable*   No              
                          *Permitted        
                          Values          
                          *               
     *Type*               `numeric'        
     *Default*            `4'             
     *Min Value*          `1'             


     The minimum length of the word to be included in a `FULLTEXT'
     index.

     *Note*:

     `FULLTEXT' indexes must be rebuilt after changing this variable.
     Use `REPAIR TABLE TBL_NAME QUICK'.

   *  `ft_query_expansion_limit'

     Options for ft_query_expansion_limit      *Command-Line        `--ft_query_expansion_limit=#'        
     Format*                              
     *Option-File Format* `ft_query_expansion_limit'        
     *Option Sets         Yes,            
     Variable*            `ft_query_expansion_limit'        
     *Variable Name*      `ft_query_expansion_limit'        
     *Variable Scope*     Global          
     *Dynamic Variable*   No              
                          *Permitted        
                          Values          
                          *               
     *Type*               `numeric'        
     *Default*            `20'            
     *Range*              `0 ..           
                          1000'           


     The number of top matches to use for full-text searches performed
     using `WITH QUERY EXPANSION'.

   *  `ft_stopword_file'

     Options for ft_stopword_file      *Command-Line        `--ft_stopword_file=file_name'        
     Format*                              
     *Option-File Format* `ft_stopword_file=file_name'        
     *Option Sets         Yes,            
     Variable*            `ft_stopword_file'        
     *Variable Name*      `ft_stopword_file'        
     *Variable Scope*     Global          
     *Dynamic Variable*   No              
                          *Permitted        
                          Values          
                          *               
     *Type*               `file           
                          name'           


     The file from which to read the list of stopwords for full-text
     searches. The server looks for the file in the data directory
     unless an absolute path name is given to specify a different
     directory. All the words from the file are used; comments are
     _not_ honored. By default, a built-in list of stopwords is used
     (as defined in the `myisam/ft_static.c' file). Setting this
     variable to the empty string (`''') disables stopword filtering.
     See also *Note fulltext-stopwords::.

     *Note*:

     `FULLTEXT' indexes must be rebuilt after changing this variable or
     the contents of the stopword file.  Use `REPAIR TABLE TBL_NAME
     QUICK'.

   *  `group_concat_max_len'

     Options for group_concat_max_len      *Command-Line        `--group_concat_max_len=#'        
     Format*                              
     *Option-File Format* `group_concat_max_len'        
     *Option Sets         Yes,            
     Variable*            `group_concat_max_len'        
     *Variable Name*      `group_concat_max_len'        
     *Variable Scope*     Global,         
                          Session         
     *Dynamic Variable*   Yes             
                          *Permitted        
                          Values          
                          *               
     *Platform Bit Size*  `32'            
     *Type*               `numeric'        
     *Default*            `1024'          
     *Range*              `4 ..           
                          4294967295'        
                          *Permitted        
                          Values          
                          *               
     *Platform Bit Size*  `64'            
     *Type*               `numeric'        
     *Default*            `1024'          
     *Range*              `4 ..           
                          18446744073709547520'        


     The maximum permitted result length in bytes for the
     `GROUP_CONCAT()' function. The default is 1024.

   *  `have_archive'

     `YES' if *Note `mysqld': mysqld. supports `ARCHIVE' tables, `NO' if
     not.

   *  `have_bdb'

     `YES' if *Note `mysqld': mysqld. supports `BDB' tables. `DISABLED'
     if `--skip-bdb' is used.

   *  `have_blackhole_engine'

     `YES' if *Note `mysqld': mysqld. supports `BLACKHOLE' tables, `NO'
     if not.

   *  `have_compress'

     `YES' if the `zlib' compression library is available to the server,
     `NO' if not. If not, the `COMPRESS()' and `UNCOMPRESS()' functions
     cannot be used.

   *  `have_crypt'

     `YES' if the `crypt()' system call is available to the server, `NO'
     if not. If not, the `ENCRYPT()' function cannot be used.

   *  `have_csv'

     `YES' if *Note `mysqld': mysqld. supports `CSV' tables, `NO' if
     not.

   *  `have_example_engine'

     `YES' if *Note `mysqld': mysqld. supports `EXAMPLE' tables, `NO' if
     not.

   *  `have_federated_engine'

     `YES' if *Note `mysqld': mysqld. supports `FEDERATED' tables, `NO'
     if not. This variable was added in MySQL 5.0.3.

   *  `have_geometry'

     `YES' if the server supports spatial data types, `NO' if not.

   *  `have_innodb'

     `YES' if *Note `mysqld': mysqld. supports `InnoDB' tables.
     `DISABLED' if `--skip-innodb' is used.

   *  `have_isam'

     In MySQL 5.0, this variable appears only for reasons of backward
     compatibility. It is always `NO' because `ISAM' tables are no
     longer supported.

   *  `have_merge_engine'

     `YES' if *Note `mysqld': mysqld. supports `MERGE' tables.
     `DISABLED' if `--skip-merge' is used. This variable was added in
     MySQL 5.0.24.

   *  `have_openssl'

     `YES' if *Note `mysqld': mysqld. supports SSL connections, `NO' if
     not. As of MySQL 5.0.38, this variable is an alias for `have_ssl'.

   *  `have_query_cache'

     `YES' if *Note `mysqld': mysqld. supports the query cache, `NO' if
     not.

   *  `have_raid'

     In MySQL 5.0, this variable appears only for reasons of backward
     compatibility. It is always `NO' because `RAID' tables are no
     longer supported.

   *  `have_rtree_keys'

     `YES' if `RTREE' indexes are available, `NO' if not. (These are
     used for spatial indexes in `MyISAM' tables.)

   *  `have_ssl'

     `YES' if *Note `mysqld': mysqld. supports SSL connections, `NO' if
     not.  `DISABLED' indicates that the server was compiled with SSL
     support, but but was not started with the appropriate `--ssl-XXX'
     options.  See *Note secure-using-ssl::, for more information.

     This variable was added in MySQL 5.0.38. Before that, use
     `have_openssl'.

   *  `have_symlink'

     `YES' if symbolic link support is enabled, `NO' if not. This is
     required on Unix for support of the `DATA DIRECTORY' and `INDEX
     DIRECTORY' table options, and on Windows for support of data
     directory symlinks.

   *  `hostname'

     Options for hostname      *Version Introduced* 5.0.38          
     *Variable Name*      `hostname'        
     *Variable Scope*     Global          
     *Dynamic Variable*   No              
                          *Permitted        
                          Values          
                          *               
     *Type*               `string'        


     The server sets this variable to the server host name at startup.
     This variable was added in MySQL 5.0.38.

   *  `identity'

     This variable is a synonym for the `last_insert_id' variable. It
     exists for compatibility with other database systems. You can read
     its value with `SELECT @@identity', and set it using `SET
     identity'.

   *  `init_connect'

     Options for init_connect      *Command-Line        `--init-connect=name'        
     Format*                              
     *Option-File Format* `init_connect'        
     *Option Sets         Yes,            
     Variable*            `init_connect'        
     *Variable Name*      `init_connect'        
     *Variable Scope*     Global          
     *Dynamic Variable*   Yes             
                          *Permitted        
                          Values          
                          *               
     *Type*               `string'        


     A string to be executed by the server for each client that
     connects. The string consists of one or more SQL statements,
     separated by semicolon characters. For example, each client
     session begins by default with autocommit mode enabled. There is
     no global `autocommit' system variable to specify that autocommit
     should be disabled by default, but `init_connect' can be used to
     achieve the same effect:

          SET GLOBAL init_connect='SET autocommit=0';

     The `init_connect' variable can also be set on the command line or
     in an option file. To set the variable as just shown using an
     option file, include these lines:

          [mysqld]
          init_connect='SET autocommit=0'

     The content of `init_connect' is not executed for users that have
     the `SUPER' privilege. This is done so that an erroneous value for
     `init_connect' does not prevent all clients from connecting. For
     example, the value might contain a statement that has a syntax
     error, thus causing client connections to fail. Not executing
     `init_connect' for users that have the `SUPER' privilege enables
     them to open a connection and fix the `init_connect' value.

   *  `init_file'

     Options for init-file      *Command-Line        `--init-file=file_name'        
     Format*                              
     *Option-File Format* `init-file=file_name'        
     *Option Sets         Yes,            
     Variable*            `init_file'        
     *Variable Name*      `init_file'        
     *Variable Scope*     Global          
     *Dynamic Variable*   No              
                          *Permitted        
                          Values          
                          *               
     *Type*               `file           
                          name'           


     The name of the file specified with the `--init-file' option when
     you start the server. This should be a file containing SQL
     statements that you want the server to execute when it starts.
     Each statement must be on a single line and should not include
     comments. No statement terminator such as `;', `\g', or `\G'
     should be given at the end of each statement.

     Note that the `--init-file' option is unavailable if MySQL was
     configured with the `--disable-grant-options' option. See *Note
     source-configuration-options::.

   * `innodb_XXX'

     `InnoDB' system variables are listed in *Note innodb-parameters::.

   *  `insert_id'

     The value to be used by the following *Note `INSERT': insert. or
     *Note `ALTER TABLE': alter-table. statement when inserting an
     `AUTO_INCREMENT' value. This is mainly used with the binary log.

   *  `interactive_timeout'

     Options for interactive_timeout      *Command-Line        `--interactive_timeout=#'        
     Format*                              
     *Option-File Format* `interactive_timeout'        
     *Option Sets         Yes,            
     Variable*            `interactive_timeout'        
     *Variable Name*      `interactive_timeout'        
     *Variable Scope*     Global,         
                          Session         
     *Dynamic Variable*   Yes             
                          *Permitted        
                          Values          
                          *               
     *Type*               `numeric'        
     *Default*            `28800'         
     *Min Value*          `1'             


     The number of seconds the server waits for activity on an
     interactive connection before closing it. An interactive client is
     defined as a client that uses the `CLIENT_INTERACTIVE' option to
     *Note `mysql_real_connect()': mysql-real-connect. See also
     `wait_timeout'.

   *  `join_buffer_size'

     Options for join_buffer_size      *Command-Line        `--join_buffer_size=#'        
     Format*                              
     *Option-File Format* `join_buffer_size'        
     *Option Sets         Yes,            
     Variable*            `join_buffer_size'        
     *Variable Name*      `join_buffer_size'        
     *Variable Scope*     Global,         
                          Session         
     *Dynamic Variable*   Yes             


     The minimum size of the buffer that is used for plain index scans,
     range index scans, and joins that do not use indexes and thus
     perform full table scans. Normally, the best way to get fast joins
     is to add indexes. Increase the value of `join_buffer_size' to get
     a faster full join when adding indexes is not possible. One join
     buffer is allocated for each full join between two tables. For a
     complex join between several tables for which indexes are not
     used, multiple join buffers might be necessary. There is no gain
     from setting the buffer larger than required to hold each matching
     row, and all joins allocate at least the minimum size, so use
     caution in setting this variable to a large value globally. It is
     better to keep the global setting small and change to a larger
     setting only in sessions that are doing large joins. Memory
     allocation time can cause substantial performance drops if the
     global size is larger than needed by most queries that use it.

     The maximum permissible setting for `join_buffer_size' is 4GB.

   *  `keep_files_on_create'

     Options for keep_files_on_create      *Version Introduced* 5.0.48          
     *Command-Line        `--keep_files_on_create=#'        
     Format*                              
     *Option-File Format* `keep_files_on_create'        
     *Option Sets         Yes,            
     Variable*            `keep_files_on_create'        
     *Variable Name*      `keep_files_on_create'        
     *Variable Scope*     Global,         
                          Session         
     *Dynamic Variable*   Yes             
                          *Permitted        
                          Values          
                          *               
     *Type*               `boolean'        
     *Default*            `OFF'           


     If a `MyISAM' table is created with no `DATA DIRECTORY' option, the
     `.MYD' file is created in the database directory. By default, if
     `MyISAM' finds an existing `.MYD' file in this case, it overwrites
     it. The same applies to `.MYI' files for tables created with no
     `INDEX DIRECTORY' option. To suppress this behavior, set the
     `keep_files_on_create' variable to `ON' (1), in which case
     `MyISAM' will not overwrite existing files and returns an error
     instead. The default value is `OFF' (0).

     If a `MyISAM' table is created with a `DATA DIRECTORY' or `INDEX
     DIRECTORY' option and an existing `.MYD' or `.MYI' file is found,
     MyISAM always returns an error. It will not overwrite a file in
     the specified directory.

     This variable was added in MySQL 5.0.48.

   *  `key_buffer_size'

     Options for key_buffer_size      *Command-Line        `--key_buffer_size=#'        
     Format*                              
     *Option-File Format* `key_buffer_size'        
     *Option Sets         Yes,            
     Variable*            `key_buffer_size'        
     *Variable Name*      `key_buffer_size'        
     *Variable Scope*     Global          
     *Dynamic Variable*   Yes             


     Index blocks for `MyISAM' tables are buffered and are shared by
     all threads.  `key_buffer_size' is the size of the buffer used for
     index blocks. The key buffer is also known as the key cache.

     The maximum permissible setting for `key_buffer_size' is 4GB on
     32-bit platforms. As of MySQL 5.0.52, values larger than 4GB are
     permitted for 64-bit platforms (except 64-bit Windows, for which
     large values are truncated to 4GB with a warning). The effective
     maximum size might be less, depending on your available physical
     RAM and per-process RAM limits imposed by your operating system or
     hardware platform. The value of this variable indicates the amount
     of memory requested. Internally, the server allocates as much
     memory as possible up to this amount, but the actual allocation
     might be less.

     You can increase the value to get better index handling for all
     reads and multiple writes; on a system whose primary function is
     to run MySQL using the *Note `MyISAM': myisam-storage-engine.
     storage engine, 25% of the machine's total memory is an acceptable
     value for this variable. However, you should be aware that, if you
     make the value too large (for example, more than 50% of the
     machine's total memory), your system might start to page and
     become extremely slow. This is because MySQL relies on the
     operating system to perform file system caching for data reads, so
     you must leave some room for the file system cache.  You should
     also consider the memory requirements of any other storage engines
     that you may be using in addition to *Note `MyISAM':
     myisam-storage-engine.

     For even more speed when writing many rows at the same time, use
     *Note `LOCK TABLES': lock-tables. See *Note insert-speed::.

     You can check the performance of the key buffer by issuing a *Note
     `SHOW STATUS': show-status. statement and examining the
     `Key_read_requests', `Key_reads', `Key_write_requests', and
     `Key_writes' status variables.  (See *Note show::.) The
     `Key_reads/Key_read_requests' ratio should normally be less than
     0.01. The `Key_writes/Key_write_requests' ratio is usually near 1
     if you are using mostly updates and deletes, but might be much
     smaller if you tend to do updates that affect many rows at the
     same time or if you are using the `DELAY_KEY_WRITE' table option.

     The fraction of the key buffer in use can be determined using
     `key_buffer_size' in conjunction with the `Key_blocks_unused'
     status variable and the buffer block size, which is available from
     the `key_cache_block_size' system variable:

          1 - ((Key_blocks_unused * key_cache_block_size) / key_buffer_size)

     This value is an approximation because some space in the key
     buffer is allocated internally for administrative structures.
     Factors that influence the amount of overhead for these structures
     include block size and pointer size. As block size increases, the
     percentage of the key buffer lost to overhead tends to decrease.
     Larger blocks results in a smaller number of read operations
     (because more keys are obtained per read), but conversely an
     increase in reads of keys that are not examined (if not all keys
     in a block are relevant to a query).

     It is possible to create multiple `MyISAM' key caches. The size
     limit of 4GB applies to each cache individually, not as a group.
     See *Note myisam-key-cache::.

   *  `key_cache_age_threshold'

     Options for key_cache_age_threshold      *Command-Line        `--key_cache_age_threshold=#'        
     Format*                              
     *Option-File Format* `key_cache_age_threshold'        
     *Option Sets         Yes,            
     Variable*            `key_cache_age_threshold'        
     *Variable Name*      `key_cache_age_threshold'        
     *Variable Scope*     Global          
     *Dynamic Variable*   Yes             
                          *Permitted        
                          Values          
                          *               
     *Platform Bit Size*  `32'            
     *Type*               `numeric'        
     *Default*            `300'           
     *Range*              `100            
                          ..              
                          4294967295'        
                          *Permitted        
                          Values          
                          *               
     *Platform Bit Size*  `64'            
     *Type*               `numeric'        
     *Default*            `300'           
     *Range*              `100            
                          ..              
                          18446744073709547520'        


     This value controls the demotion of buffers from the hot sublist
     of a key cache to the warm sublist. Lower values cause demotion to
     happen more quickly. The minimum value is 100. The default value
     is 300. See *Note myisam-key-cache::.

   *  `key_cache_block_size'

     Options for key_cache_block_size      *Command-Line        `--key_cache_block_size=#'        
     Format*                              
     *Option-File Format* `key_cache_block_size'        
     *Option Sets         Yes,            
     Variable*            `key_cache_block_size'        
     *Variable Name*      `key_cache_block_size'        
     *Variable Scope*     Global          
     *Dynamic Variable*   Yes             
                          *Permitted        
                          Values          
                          *               
     *Type*               `numeric'        
     *Default*            `1024'          
     *Range*              `512            
                          ..              
                          16384'          


     The size in bytes of blocks in the key cache. The default value is
     1024. See *Note myisam-key-cache::.

   *  `key_cache_division_limit'

     Options for key_cache_division_limit      *Command-Line        `--key_cache_division_limit=#'        
     Format*                              
     *Option-File Format* `key_cache_division_limit'        
     *Option Sets         Yes,            
     Variable*            `key_cache_division_limit'        
     *Variable Name*      `key_cache_division_limit'        
     *Variable Scope*     Global          
     *Dynamic Variable*   Yes             
                          *Permitted        
                          Values          
                          *               
     *Type*               `numeric'        
     *Default*            `100'           
     *Range*              `1 ..           
                          100'            


     The division point between the hot and warm sublists of the key
     cache buffer list. The value is the percentage of the buffer list
     to use for the warm sublist. Permissible values range from 1 to
     100. The default value is 100. See *Note myisam-key-cache::.

   *  `language'

     Options for language      *Command-Line        `--language=name'        
     Format*                              
     **                   `-L'            
     *Option-File Format* `language'        
     *Option Sets         Yes,            
     Variable*            `language'        
     *Variable Name*      `language'        
     *Variable Scope*     Global          
     *Dynamic Variable*   No              
     *Deprecated*         5.6.1           
                          *Permitted        
                          Values          
                          *               
     *Type*               `directory        
                          name'           
     *Default*            `/usr/local/mysql/share/mysql/english/'        


     The directory where error messages are located. See *Note
     error-message-language::.

   *  `large_files_support'

     Options for large_files_support      *Variable Name*      `large_files_support'        
     *Variable Scope*     Global          
     *Dynamic Variable*   No              


     Whether *Note `mysqld': mysqld. was compiled with options for
     large file support.

   *  `large_pages'

     Options for large-pages      *Version Introduced* 5.0.3           
     *Command-Line        `--large-pages'        
     Format*                              
     *Option-File Format* `large-pages'        
     *Option Sets         Yes,            
     Variable*            `large_pages'        
     *Variable Name*      `large_pages'        
     *Variable Scope*     Global          
     *Dynamic Variable*   No              
     *Platform Specific*  linux           
                          *Permitted        
                          Values          
                          *               
     *Type* (linux)       `boolean'        
     *Default*            `FALSE'         


     Whether large page support is enabled (via the `--large-pages'
     option). See *Note large-page-support::. This variable was added
     in MySQL 5.0.3.

     For more information, see the entry for the `--large-pages' server
     option.

   *  `large_page_size'

     Options for large_page_size      *Version Introduced* 5.0.3           
     *Variable Name*      `large_page_size'        
     *Variable Scope*     Global          
     *Dynamic Variable*   No              
                          *Permitted        
                          Values          
                          *               
     *Type* (linux)       `numeric'        
     *Default*            `0'             


     If large page support is enabled, this shows the size of memory
     pages. Currently, large memory pages are supported only on Linux;
     on other platforms, the value of this variable is always 0. This
     variable was added in MySQL 5.0.3.

     For more information, see the entry for the `--large-pages' server
     option.

   *  `last_insert_id'

     The value to be returned from `LAST_INSERT_ID()'. This is stored
     in the binary log when you use `LAST_INSERT_ID()' in a statement
     that updates a table. Setting this variable does not update the
     value returned by the *Note `mysql_insert_id()': mysql-insert-id.
     C API function.

   *  `lc_time_names'

     Options for lc_time_names      *Version Introduced* 5.0.25          
     *Variable Name*      `lc_time_names'        
     *Variable Scope*     Global,         
                          Session         
     *Dynamic Variable*   Yes             
                          *Permitted        
                          Values          
                          *               
     *Type*               `string'        


     This variable specifies the locale that controls the language used
     to display day and month names and abbreviations. This variable
     affects the output from the `DATE_FORMAT()', `DAYNAME()' and
     `MONTHNAME()' functions. Locale names are POSIX-style values such
     as `'ja_JP'' or `'pt_BR''. The default value is `'en_US''
     regardless of your system's locale setting. For further
     information, see *Note locale-support::. This variable was added in
     MySQL 5.0.25.

   *  `license'

     Options for license      *Variable Name*      `license'        
     *Variable Scope*     Global          
     *Dynamic Variable*   No              
                          *Permitted        
                          Values          
                          *               
     *Type*               `string'        
     *Default*            `GPL'           


     The type of license the server has.

   *  `local_infile'

     Options for local_infile      *Variable Name*      `local_infile'        
     *Variable Scope*     Global          
     *Dynamic Variable*   Yes             
                          *Permitted        
                          Values          
                          *               
     *Type*               `boolean'        


     Whether `LOCAL' is supported for *Note `LOAD DATA INFILE':
     load-data. statements. See *Note load-data-local::.

   *  `locked_in_memory'

     Options for locked_in_memory      *Variable Name*      `locked_in_memory'        
     *Variable Scope*     Global          
     *Dynamic Variable*   No              


     Whether *Note `mysqld': mysqld. was locked in memory with
     `--memlock'.

   *  `log'

     Whether logging of all statements to the general query log is
     enabled. See *Note query-log::.

   *  `log_bin'

     Options for log_bin      *Variable Name*      `log_bin'        
     *Variable Scope*     Global          
     *Dynamic Variable*   No              


     Whether the binary log is enabled. If the `--log-bin' option is
     used, then the value of this variable is `ON'; otherwise it is
     `OFF'. This variable reports only on the status of binary logging
     (enabled or disabled); it does not actually report the value to
     which `--log-bin' is set.

     See *Note binary-log::.

   *  `log_bin_trust_function_creators'

     Options for log-bin-trust-function-creators      *Version Introduced* 5.0.16          
     *Command-Line        `--log-bin-trust-function-creators'        
     Format*                              
     *Option-File Format* `log-bin-trust-function-creators'        
     *Option Sets         Yes,            
     Variable*            `log_bin_trust_function_creators'        
     *Variable Name*      `log_bin_trust_function_creators'        
     *Variable Scope*     Global          
     *Dynamic Variable*   Yes             
                          *Permitted        
                          Values          
                          *               
     *Type*               `boolean'        
     *Default*            `FALSE'         


     This variable applies when binary logging is enabled. It controls
     whether stored function creators can be trusted not to create
     stored functions that will cause unsafe events to be written to
     the binary log. If set to 0 (the default), users are not permitted
     to create or alter stored functions unless they have the `SUPER'
     privilege in addition to the `CREATE ROUTINE' or `ALTER ROUTINE'
     privilege. A setting of 0 also enforces the restriction that a
     function must be declared with the `DETERMINISTIC' characteristic,
     or with the `READS SQL DATA' or `NO SQL' characteristic. If the
     variable is set to 1, MySQL does not enforce these restrictions on
     stored function creation. This variable also applies to trigger
     creation. See *Note stored-programs-logging::.

     This variable was added in MySQL 5.0.16.

   *  `log_bin_trust_routine_creators'

     This is the old name for `log_bin_trust_function_creators'.
     Before MySQL 5.0.16, it also applies to stored procedures, not
     just stored functions. As of 5.0.16, this variable is deprecated.
     It is recognized for backward compatibility but its use results in
     a warning.

     This variable was added in MySQL 5.0.6. It is removed in MySQL 5.5.

   *  `log_error'

     Options for log-error      *Command-Line        `--log-error[=name]'        
     Format*                              
     *Option-File Format* `log-error'        
     *Option Sets         Yes,            
     Variable*            `log_error'        
     *Variable Name*      `log_error'        
     *Variable Scope*     Global          
     *Dynamic Variable*   No              
                          *Permitted        
                          Values          
                          *               
     *Type*               `file           
                          name'           


     The location of the error log.

   *  `log_queries_not_using_indexes'

     Options for log-queries-not-using-indexes      *Command-Line        `--log-queries-not-using-indexes'        
     Format*                              
     *Option-File Format* `log-queries-not-using-indexes'        
     *Option Sets         Yes,            
     Variable*            `log_queries_not_using_indexes'        
     *Variable Name*      `log_queries_not_using_indexes'        
     *Variable Scope*     Global          
     *Dynamic Variable*   Yes             
                          *Permitted        
                          Values          
                          *               
     *Type*               `boolean'        
     *Default*            `OFF'           


     Whether queries that do not use indexes are logged to the slow
     query log. See *Note slow-query-log::. This variable was added in
     MySQL 5.0.23.

   *  `log_slow_queries'

     Options for log-slow-queries      *Command-Line        `--log-slow-queries[=name]'        
     Format*                              
     *Option-File Format* `log-slow-queries'        
     *Option Sets         Yes,            
     Variable*            `log_slow_queries'        
     *Variable Name*      `log_slow_queries'        
     *Variable Scope*     Global          
     *Dynamic Variable*   No              
     *Deprecated*         5.1.29,         
                          by              
                          `slow-query-log'        
                          *Permitted        
                          Values          
                          *               
     *Type*               `boolean'        


     Whether slow queries should be logged. `Slow' is determined by the
     value of the `long_query_time' variable. See *Note
     slow-query-log::.

   *  `log_warnings'

     Options for log-warnings      *Command-Line        `--log-warnings[=#]'        
     Format*                              
     **                   `-W             
                          [#]'            
     *Option-File Format* `log-warnings'        
     *Option Sets         Yes,            
     Variable*            `log_warnings'        
     *Variable Name*      `log_warnings'        
     *Variable Scope*     Global,         
                          Session         
     *Dynamic Variable*   Yes             
     *Disabled by*        `skip-log-warnings'        
                          *Permitted        
                          Values          
                          *               
     *Platform Bit Size*  `64'            
     *Type*               `numeric'        
     *Default*            `1'             
     *Range*              `0 ..           
                          18446744073709547520'        


     Whether to produce additional warning messages. It is enabled (1)
     by default and can be disabled by setting it to 0. Aborted
     connections are not logged to the error log unless the value is
     greater than 1.

   *  `long_query_time'

     Options for long_query_time      *Command-Line        `--long_query_time=#'        
     Format*                              
     *Option-File Format* `long_query_time'        
     *Option Sets         Yes,            
     Variable*            `long_query_time'        
     *Variable Name*      `long_query_time'        
     *Variable Scope*     Global,         
                          Session         
     *Dynamic Variable*   Yes             
                          *Permitted        
                          Values          
                          (<=             
                          5.0.20)*        
     *Type*               `numeric'        
     *Default*            `10'            
     *Min Value*          `1'             


     If a query takes longer than this many seconds, the server
     increments the `Slow_queries' status variable. If you are using the
     `--log-slow-queries' option, the query is logged to the slow query
     log file. This value is measured in real time, not CPU time, so a
     query that is under the threshold on a lightly loaded system might
     be above the threshold on a heavily loaded one. The minimum value
     is 1. The default is 10. See *Note slow-query-log::.

   *  `low_priority_updates'

     Options for low-priority-updates      *Command-Line        `--low-priority-updates'        
     Format*                              
     *Option-File Format* `low-priority-updates'        
     *Option Sets         Yes,            
     Variable*            `low_priority_updates'        
     *Variable Name*      `low_priority_updates'        
     *Variable Scope*     Global,         
                          Session         
     *Dynamic Variable*   Yes             
                          *Permitted        
                          Values          
                          *               
     *Type*               `boolean'        
     *Default*            `FALSE'         


     If set to `1', all *Note `INSERT': insert, *Note `UPDATE': update,
     *Note `DELETE': delete, and `LOCK TABLE WRITE' statements wait
     until there is no pending *Note `SELECT': select. or `LOCK TABLE
     READ' on the affected table. This affects only storage engines
     that use only table-level locking (such as `MyISAM', `MEMORY', and
     `MERGE'). This variable previously was named
     `sql_low_priority_updates'.

   *  `lower_case_file_system'

     Options for lower_case_file_system      *Command-Line        `--lower_case_file_system[=#]'        
     Format*                              
     *Option-File Format* `lower_case_file_system'        
     *Option Sets         Yes,            
     Variable*            `lower_case_file_system'        
     *Variable Name*      `lower_case_file_system'        
     *Variable Scope*     Global          
     *Dynamic Variable*   No              
                          *Permitted        
                          Values          
                          *               
     *Type*               `boolean'        


     This variable describes the case sensitivity of file names on the
     file system where the data directory is located.  `OFF' means file
     names are case sensitive, `ON' means they are not case sensitive.
     This variable is read only because it reflects a file system
     attribute and setting it would have no effect on the file system.

   *  `lower_case_table_names'

     Options for lower_case_table_names      *Command-Line        `--lower_case_table_names[=#]'        
     Format*                              
     *Option-File Format* `lower_case_table_names'        
     *Option Sets         Yes,            
     Variable*            `lower_case_table_names'        
     *Variable Name*      `lower_case_table_names'        
     *Variable Scope*     Global          
     *Dynamic Variable*   No              
                          *Permitted        
                          Values          
                          *               
     *Type*               `numeric'        
     *Default*            `0'             
     *Range*              `0 ..           
                          2'              


     If set to 0, table names are stored as specified and comparisons
     are case sensitive. If set to 1, table names are stored in
     lowercase on disk and comparisons are not case sensitive. If set
     to 2, table names are stored as given but compared in lowercase.
     This option also applies to database names and table aliases. For
     additional information, see *Note identifier-case-sensitivity::.

     You should _not_ set this variable to 0 if you are running MySQL
     on a system that has case-insensitive file names (such as Windows
     or Mac OS X). If you set this variable to 0 on such a system and
     access `MyISAM' tablenames using different lettercases, index
     corruption may result. On Windows the default value is 1. On Mac
     OS X, the default value is 2.

     If you are using `InnoDB' or MySQL Cluster (`NDB') tables, you
     should set this variable to 1 on all platforms to force names to
     be converted to lowercase.

     The setting of this variable has no effect on replication
     filtering options. See *Note replication-rules::, for more
     information.

     You should not use different settings for `lower_case_table_names'
     on replication masters and slaves. In particular, you should not
     do this when the slave uses a case-sensitive file system, as this
     can cause replication to fail. For more information, see *Note
     replication-features-variables::.

   *  `max_allowed_packet'

     Options for max_allowed_packet      *Command-Line        `--max_allowed_packet=#'        
     Format*                              
     *Option-File Format* `max_allowed_packet'        
     *Option Sets         Yes,            
     Variable*            `max_allowed_packet'        
     *Variable Name*      `max_allowed_packet'        
     *Variable Scope*     Global          
     *Dynamic Variable*   Yes             
                          *Permitted        
                          Values          
                          *               
     *Type*               `numeric'        
     *Default*            `1048576'        
     *Range*              `1024           
                          ..              
                          1073741824'        


     The maximum size of one packet or any generated/intermediate
     string.

     The packet message buffer is initialized to `net_buffer_length'
     bytes, but can grow up to `max_allowed_packet' bytes when needed.
     This value by default is small, to catch large (possibly
     incorrect) packets.

     You must increase this value if you are using large *Note `BLOB':
     blob. columns or long strings.  It should be as big as the largest
     *Note `BLOB': blob. you want to use. The protocol limit for
     `max_allowed_packet' is 1GB.  The value should be a multiple of
     1024; nonmultiples are rounded down to the nearest multiple.

     When you change the message buffer size by changing the value of
     the `max_allowed_packet' variable, you should also change the
     buffer size on the client side if your client program permits it.
     On the client side, `max_allowed_packet' has a default of 1GB.
     Some programs such as *Note `mysql': mysql.  and *Note
     `mysqldump': mysqldump. enable you to change the client-side value
     by setting `max_allowed_packet' on the command line or in an
     option file.

     As of MySQL 5.0.84, the session value of this variable is read
     only. Before 5.0.84, setting the session value is permitted but
     has no effect.

   *  `max_connect_errors'

     Options for max_connect_errors      *Command-Line        `--max_connect_errors=#'        
     Format*                              
     *Option-File Format* `max_connect_errors'        
     *Option Sets         Yes,            
     Variable*            `max_connect_errors'        
     *Variable Name*      `max_connect_errors'        
     *Variable Scope*     Global          
     *Dynamic Variable*   Yes             
                          *Permitted        
                          Values          
                          *               
     *Platform Bit Size*  `32'            
     *Type*               `numeric'        
     *Default*            `10'            
     *Range*              `1 ..           
                          4294967295'        
                          *Permitted        
                          Values          
                          *               
     *Platform Bit Size*  `64'            
     *Type*               `numeric'        
     *Default*            `10'            
     *Range*              `1 ..           
                          18446744073709547520'        


     If there are more than this number of interrupted connections from
     a host, that host is blocked from further connections.  You can
     unblock blocked hosts with the *Note `FLUSH HOSTS': flush.
     statement. If a connection is established successfully within
     fewer than `max_connect_errors' attempts after a previous
     connection was interrupted, the error count for the host is
     cleared to zero. However, once a host is blocked, the *Note `FLUSH
     HOSTS': flush.  statement is the only way to unblock it.

   *  `max_connections'

     Options for max_connections      *Command-Line        `--max_connections=#'        
     Format*                              
     *Option-File Format* `max_connections'        
     *Option Sets         Yes,            
     Variable*            `max_connections'        
     *Variable Name*      `max_connections'        
     *Variable Scope*     Global          
     *Dynamic Variable*   Yes             


     The maximum permitted number of simultaneous client connections.
     By default, this is 100. See *Note too-many-connections::, for
     more information.

     Increasing this value increases the number of file descriptors
     that *Note `mysqld': mysqld. requires. See *Note table-cache::,
     for comments on file descriptor limits.

   *  `max_delayed_threads'

     Options for max_delayed_threads      *Command-Line        `--max_delayed_threads=#'        
     Format*                              
     *Option-File Format* `max_delayed_threads'        
     *Option Sets         Yes,            
     Variable*            `max_delayed_threads'        
     *Variable Name*      `max_delayed_threads'        
     *Variable Scope*     Global,         
                          Session         
     *Dynamic Variable*   Yes             
                          *Permitted        
                          Values          
                          *               
     *Type*               `numeric'        
     *Default*            `20'            
     *Range*              `0 ..           
                          16384'          


     Do not start more than this number of threads to handle *Note
     `INSERT DELAYED': insert-delayed. statements. If you try to insert
     data into a new table after all *Note `INSERT DELAYED':
     insert-delayed. threads are in use, the row is inserted as if the
     `DELAYED' attribute was not specified. If you set this to 0, MySQL
     never creates a thread to handle `DELAYED' rows; in effect, this
     disables `DELAYED' entirely.

     For the `SESSION' value of this variable, the only valid values
     are 0 or the `GLOBAL' value.

   *  `max_error_count'

     Options for max_error_count      *Command-Line        `--max_error_count=#'        
     Format*                              
     *Option-File Format* `max_error_count'        
     *Option Sets         Yes,            
     Variable*            `max_error_count'        
     *Variable Name*      `max_error_count'        
     *Variable Scope*     Global,         
                          Session         
     *Dynamic Variable*   Yes             
                          *Permitted        
                          Values          
                          *               
     *Type*               `numeric'        
     *Default*            `64'            
     *Range*              `0 ..           
                          65535'          


     The maximum number of error, warning, and note messages to be
     stored for display by the *Note `SHOW ERRORS': show-errors. and
     *Note `SHOW WARNINGS': show-warnings. statements.

   *  `max_heap_table_size'

     Options for max_heap_table_size      *Command-Line        `--max_heap_table_size=#'        
     Format*                              
     *Option-File Format* `max_heap_table_size'        
     *Option Sets         Yes,            
     Variable*            `max_heap_table_size'        
     *Variable Name*      `max_heap_table_size'        
     *Variable Scope*     Global,         
                          Session         
     *Dynamic Variable*   Yes             
                          *Permitted        
                          Values          
                          *               
     *Platform Bit Size*  `32'            
     *Type*               `numeric'        
     *Default*            `16777216'        
     *Range*              `16384          
                          ..              
                          4294967295'        
                          *Permitted        
                          Values          
                          *               
     *Platform Bit Size*  `64'            
     *Type*               `numeric'        
     *Default*            `16777216'        
     *Range*              `16384          
                          ..              
                          1844674407370954752'        


     This variable sets the maximum size to which user-created `MEMORY'
     tables are permitted to grow. The value of the variable is used to
     calculate `MEMORY' table `MAX_ROWS' values. Setting this variable
     has no effect on any existing `MEMORY' table, unless the table is
     re-created with a statement such as *Note `CREATE TABLE':
     create-table. or altered with *Note `ALTER TABLE': alter-table. or
     *Note `TRUNCATE TABLE': truncate-table. A server restart also sets
     the maximum size of existing `MEMORY' tables to the global
     `max_heap_table_size' value.

     This variable is also used in conjunction with `tmp_table_size' to
     limit the size of internal in-memory tables. See *Note
     internal-temporary-tables::.

   *  `max_insert_delayed_threads'

     Options for max_insert_delayed_threads      *Variable Name*      `max_insert_delayed_threads'        
     *Variable Scope*     Global,         
                          Session         
     *Dynamic Variable*   Yes             
                          *Permitted        
                          Values          
                          *               
     *Type*               `numeric'        


     This variable is a synonym for `max_delayed_threads'.

   *  `max_join_size'

     Options for max_join_size      *Command-Line        `--max_join_size=#'        
     Format*                              
     *Option-File Format* `max_join_size'        
     *Option Sets         Yes,            
     Variable*            `max_join_size'        
     *Variable Name*      `max_join_size'        
     *Variable Scope*     Global,         
                          Session         
     *Dynamic Variable*   Yes             
                          *Permitted        
                          Values          
                          *               
     *Type*               `numeric'        
     *Default*            `4294967295'        
     *Range*              `1 ..           
                          4294967295'        


     Do not permit *Note `SELECT': select. statements that probably
     need to examine more than `max_join_size' rows (for single-table
     statements) or row combinations (for multiple-table statements) or
     that are likely to do more than `max_join_size' disk seeks. By
     setting this value, you can catch *Note `SELECT': select.
     statements where keys are not used properly and that would
     probably take a long time. Set it if your users tend to perform
     joins that lack a `WHERE' clause, that take a long time, or that
     return millions of rows.

     Setting this variable to a value other than `DEFAULT' resets the
     value of `sql_big_selects' to `0'. If you set the
     `sql_big_selects' value again, the `max_join_size' variable is
     ignored.

     If a query result is in the query cache, no result size check is
     performed, because the result has previously been computed and it
     does not burden the server to send it to the client.

     This variable previously was named `sql_max_join_size'.

   *  `max_length_for_sort_data'

     Options for max_length_for_sort_data      *Command-Line        `--max_length_for_sort_data=#'        
     Format*                              
     *Option-File Format* `max_length_for_sort_data'        
     *Option Sets         Yes,            
     Variable*            `max_length_for_sort_data'        
     *Variable Name*      `max_length_for_sort_data'        
     *Variable Scope*     Global,         
                          Session         
     *Dynamic Variable*   Yes             
                          *Permitted        
                          Values          
                          *               
     *Type*               `numeric'        
     *Default*            `1024'          
     *Range*              `4 ..           
                          8388608'        


     The cutoff on the size of index values that determines which
     `filesort' algorithm to use. See *Note order-by-optimization::.

   *  `max_prepared_stmt_count'

     Options for max_prepared_stmt_count      *Version Introduced* 5.0.21          
     *Command-Line        `--max_prepared_stmt_count=#'        
     Format*                              
     *Option-File Format* `max_prepared_stmt_count'        
     *Option Sets         Yes,            
     Variable*            `max_prepared_stmt_count'        
     *Variable Name*      `max_prepared_stmt_count'        
     *Variable Scope*     Global          
     *Dynamic Variable*   Yes             
                          *Permitted        
                          Values          
                          *               
     *Type*               `numeric'        
     *Default*            `16382'         
     *Range*              `0 ..           
                          1048576'        


     This variable limits the total number of prepared statements in
     the server. It can be used in environments where there is the
     potential for denial-of-service attacks based on running the
     server out of memory by preparing huge numbers of statements. If
     the value is set lower than the current number of prepared
     statements, existing statements are not affected and can be used,
     but no new statements can be prepared until the current number
     drops below the limit. The default value is 16,382. The
     permissible range of values is from 0 to 1 million. Setting the
     value to 0 disables prepared statements.  This variable was added
     in MySQL 5.0.21.

   *  `max_relay_log_size'

     Options for max_relay_log_size      *Command-Line        `--max_relay_log_size=#'        
     Format*                              
     *Option-File Format* `max_relay_log_size'        
     *Option Sets         Yes,            
     Variable*            `max_relay_log_size'        
     *Variable Name*      `max_relay_log_size'        
     *Variable Scope*     Global          
     *Dynamic Variable*   Yes             
                          *Permitted        
                          Values          
                          *               
     *Type*               `numeric'        
     *Default*            `0'             
     *Range*              `0 ..           
                          1073741824'        


     If a write by a replication slave to its relay log causes the
     current log file size to exceed the value of this variable, the
     slave rotates the relay logs (closes the current file and opens
     the next one). If `max_relay_log_size' is 0, the server uses
     `max_binlog_size' for both the binary log and the relay log. If
     `max_relay_log_size' is greater than 0, it constrains the size of
     the relay log, which enables you to have different sizes for the
     two logs. You must set `max_relay_log_size' to between 4096 bytes
     and 1GB (inclusive), or to 0. The default value is 0. See *Note
     replication-implementation-details::.

   *  `max_seeks_for_key'

     Options for max_seeks_for_key      *Command-Line        `--max_seeks_for_key=#'        
     Format*                              
     *Option-File Format* `max_seeks_for_key'        
     *Option Sets         Yes,            
     Variable*            `max_seeks_for_key'        
     *Variable Name*      `max_seeks_for_key'        
     *Variable Scope*     Global,         
                          Session         
     *Dynamic Variable*   Yes             
                          *Permitted        
                          Values          
                          *               
     *Platform Bit Size*  `32'            
     *Type*               `numeric'        
     *Default*            `4294967295'        
     *Range*              `1 ..           
                          4294967295'        
                          *Permitted        
                          Values          
                          *               
     *Platform Bit Size*  `64'            
     *Type*               `numeric'        
     *Default*            `18446744073709547520'        
     *Range*              `1 ..           
                          18446744073709547520'        


     Limit the assumed maximum number of seeks when looking up rows
     based on a key. The MySQL optimizer assumes that no more than this
     number of key seeks are required when searching for matching rows
     in a table by scanning an index, regardless of the actual
     cardinality of the index (see *Note show-index::). By setting this
     to a low value (say, 100), you can force MySQL to prefer indexes
     instead of table scans.

   *  `max_sort_length'

     Options for max_sort_length      *Command-Line        `--max_sort_length=#'        
     Format*                              
     *Option-File Format* `max_sort_length'        
     *Option Sets         Yes,            
     Variable*            `max_sort_length'        
     *Variable Name*      `max_sort_length'        
     *Variable Scope*     Global,         
                          Session         
     *Dynamic Variable*   Yes             
                          *Permitted        
                          Values          
                          *               
     *Type*               `numeric'        
     *Default*            `1024'          
     *Range*              `4 ..           
                          8388608'        


     The number of bytes to use when sorting *Note `BLOB': blob. or
     *Note `TEXT': blob. values. Only the first `max_sort_length' bytes
     of each value are used; the rest are ignored.

   *  `max_sp_recursion_depth'

     Options for max_sp_recursion_depth      *Version Introduced* 5.0.17          
     *Command-Line        `--max_sp_recursion_depth[=#]'        
     Format*                              
     *Option-File Format* `max_sp_recursion_depth'        
     *Option Sets         Yes,            
     Variable*            `max_sp_recursion_depth'        
     *Variable Name*      `max_sp_recursion_depth'        
     *Variable Scope*     Global,         
                          Session         
     *Dynamic Variable*   Yes             
                          *Permitted        
                          Values          
                          *               
     *Type*               `numeric'        
     *Default*            `0'             
     *Max Value*          `255'           


     The number of times that any given stored procedure may be called
     recursively. The default value for this option is 0, which
     completely disables recursion in stored procedures. The maximum
     value is 255.

     Stored procedure recursion increases the demand on thread stack
     space. If you increase the value of `max_sp_recursion_depth', it
     may be necessary to increase thread stack size by increasing the
     value of `thread_stack' at server startup.

     This variable was added in MySQL 5.0.17.

   *  `max_tmp_tables'

     Options for max_tmp_tables      *Command-Line        `--max_tmp_tables=#'        
     Format*                              
     *Option-File Format* `max_tmp_tables'        
     *Option Sets         Yes,            
     Variable*            `max_tmp_tables'        
     *Variable Name*      `max_tmp_tables'        
     *Variable Scope*     Global,         
                          Session         
     *Dynamic Variable*   Yes             
                          *Permitted        
                          Values          
                          *               
     *Platform Bit Size*  `32'            
     *Type*               `numeric'        
     *Default*            `32'            
     *Range*              `1 ..           
                          4294967295'        
                          *Permitted        
                          Values          
                          *               
     *Platform Bit Size*  `64'            
     *Type*               `numeric'        
     *Default*            `32'            
     *Range*              `1 ..           
                          18446744073709547520'        


     The maximum number of temporary tables a client can keep open at
     the same time. (This variable does not yet do anything.)

   *  `max_user_connections'

     Options for max_user_connections      *Command-Line        `--max_user_connections=#'        
     Format*                              
     *Option-File Format* `max_user_connections'        
     *Option Sets         Yes,            
     Variable*            `max_user_connections'        
     *Variable Name*      `max_user_connections'        
     *Variable Scope*     Global,         
                          Session         
     *Dynamic Variable*   Yes             
                          *Permitted        
                          Values          
                          *               
     *Type*               `numeric'        
     *Default*            `0'             
     *Range*              `0 ..           
                          4294967295'        


     The maximum number of simultaneous connections permitted to any
     given MySQL user account. A value of 0 (the default) means `no
     limit.'

     Before MySQL 5.0.3, this variable has only a global value that can
     be set at server startup or runtime. As of MySQL 5.0.3, it also
     has a read-only session value that indicates the effective
     simultaneous-connection limit that applies to the account
     associated with the current session. The session value is
     initialized as follows:

        * If the user account has a nonzero `MAX_USER_CONNECTIONS'
          resource limit, the session `max_user_connections' value is
          set to that limit.

        * Otherwise, the session `max_user_connections' value is set to
          the global value.

     Account resource limits are specified using the *Note `GRANT':
     grant. statement. See *Note user-resources::, and *Note grant::.

   *  `max_write_lock_count'

     Options for max_write_lock_count      *Command-Line        `--max_write_lock_count=#'        
     Format*                              
     *Option-File Format* `max_write_lock_count'        
     *Option Sets         Yes,            
     Variable*            `max_write_lock_count'        
     *Variable Name*      `max_write_lock_count'        
     *Variable Scope*     Global          
     *Dynamic Variable*   Yes             
                          *Permitted        
                          Values          
                          *               
     *Platform Bit Size*  `32'            
     *Type*               `numeric'        
     *Default*            `4294967295'        
     *Range*              `1 ..           
                          4294967295'        
                          *Permitted        
                          Values          
                          *               
     *Platform Bit Size*  `64'            
     *Type*               `numeric'        
     *Default*            `18446744073709547520'        
     *Range*              `1 ..           
                          18446744073709547520'        


     After this many write locks, permit some pending read lock
     requests to be processed in between.

   *  `myisam_data_pointer_size'

     Options for myisam_data_pointer_size      *Command-Line        `--myisam_data_pointer_size=#'        
     Format*                              
     *Option-File Format* `myisam_data_pointer_size'        
     *Option Sets         Yes,            
     Variable*            `myisam_data_pointer_size'        
     *Variable Name*      `myisam_data_pointer_size'        
     *Variable Scope*     Global          
     *Dynamic Variable*   Yes             
                          *Permitted        
                          Values          
                          (<=             
                          5.0.5)*         
     *Type*               `numeric'        
     *Default*            `4'             
     *Range*              `2 ..           
                          8'              
                          *Permitted        
                          Values          
                          (>=             
                          5.0.6)*         
     *Type*               `numeric'        
     *Default*            `6'             
     *Range*              `2 ..           
                          7'              


     The default pointer size in bytes, to be used by *Note `CREATE
     TABLE': create-table. for `MyISAM' tables when no `MAX_ROWS'
     option is specified. This variable cannot be less than 2 or larger
     than 7. The default value is 6 (4 before MySQL 5.0.6). See *Note
     full-table::.

   *  `myisam_max_extra_sort_file_size' (_DEPRECATED_)

     This variable is unused as of MySQL 5.0.6.

   *  `myisam_max_sort_file_size'

     Options for myisam_max_sort_file_size      *Command-Line        `--myisam_max_sort_file_size=#'        
     Format*                              
     *Option-File Format* `myisam_max_sort_file_size'        
     *Option Sets         Yes,            
     Variable*            `myisam_max_sort_file_size'        
     *Variable Name*      `myisam_max_sort_file_size'        
     *Variable Scope*     Global          
     *Dynamic Variable*   Yes             
                          *Permitted        
                          Values          
                          *               
     *Type*               `numeric'        
     *Default*            `2147483648'        


     The maximum size of the temporary file that MySQL is permitted to
     use while re-creating a `MyISAM' index (during *Note `REPAIR
     TABLE': repair-table, *Note `ALTER TABLE': alter-table, or *Note
     `LOAD DATA INFILE': load-data.). If the file size would be larger
     than this value, the index is created using the key cache instead,
     which is slower. The value is given in bytes.

     The default value is 2GB. If `MyISAM' index files exceed this size
     and disk space is available, increasing the value may help
     performance. The space must be available in the file system
     containing the directory where the original index file is located.

   *  `myisam_mmap_size'

     Options for myisam_mmap_size      *Version Introduced* 5.0.90          
     *Command-Line        `--myisam_mmap_size=#'        
     Format*                              
     *Option-File Format* `myisam_mmap_size'        
     *Option Sets         Yes,            
     Variable*            `myisam_mmap_size'        
     *Variable Name*      `myisam_mmap_size'        
     *Variable Scope*     Global          
     *Dynamic Variable*   No              
                          *Permitted        
                          Values          
                          *               
     *Platform Bit Size*  `32'            
     *Type*               `numeric'        
     *Default*            `4294967295'        
     *Range*              `7 ..           
                          4294967295'        
                          *Permitted        
                          Values          
                          *               
     *Platform Bit Size*  `64'            
     *Type*               `numeric'        
     *Default*            `18446744073709547520'        
     *Range*              `7 ..           
                          18446744073709547520'        


     The maximum amount of memory to use for memory mapping compressed
     *Note `MyISAM': myisam-storage-engine. files. If many compressed
     `MyISAM' tables are used, the value can be decreased to reduce the
     likelihood of memory-swapping problems. This variable was added in
     MySQL 5.0.90.

   *  `myisam_recover_options'

     Options for myisam_recover_options      *Variable Name*      `myisam_recover_options'        
     *Variable Scope*     Global          
     *Dynamic Variable*   No              


     The value of the `--myisam-recover' option. See *Note
     server-options::.

   *  `myisam_repair_threads'

     Options for myisam_repair_threads      *Command-Line        `--myisam_repair_threads=#'        
     Format*                              
     *Option-File Format* `myisam_repair_threads'        
     *Option Sets         Yes,            
     Variable*            `myisam_repair_threads'        
     *Variable Name*      `myisam_repair_threads'        
     *Variable Scope*     Global,         
                          Session         
     *Dynamic Variable*   Yes             
                          *Permitted        
                          Values          
                          *               
     *Platform Bit Size*  `32'            
     *Type*               `numeric'        
     *Default*            `1'             
     *Range*              `1 ..           
                          4294967295'        
                          *Permitted        
                          Values          
                          *               
     *Platform Bit Size*  `64'            
     *Type*               `numeric'        
     *Default*            `1'             
     *Range*              `1 ..           
                          18446744073709547520'        


     If this value is greater than 1, `MyISAM' table indexes are
     created in parallel (each index in its own thread) during the
     `Repair by sorting' process. The default value is 1.

     *Note*:

     Multi-threaded repair is still _beta-quality_ code.

   *  `myisam_sort_buffer_size'

     Options for myisam_sort_buffer_size      *Command-Line        `--myisam_sort_buffer_size=#'        
     Format*                              
     *Option-File Format* `myisam_sort_buffer_size'        
     *Option Sets         Yes,            
     Variable*            `myisam_sort_buffer_size'        
     *Variable Name*      `myisam_sort_buffer_size'        
     *Variable Scope*     Global,         
                          Session         
     *Dynamic Variable*   Yes             
                          *Permitted        
                          Values          
                          *               
     *Platform Bit Size*  `32'            
     *Type*               `numeric'        
     *Default*            `8388608'        
     *Range*              `4 ..           
                          4294967295'        
                          *Permitted        
                          Values          
                          *               
     *Platform Bit Size*  `64'            
     *Type*               `numeric'        
     *Default*            `8388608'        
     *Range*              `4 ..           
                          18446744073709547520'        


     The size of the buffer that is allocated when sorting `MyISAM'
     indexes during a *Note `REPAIR TABLE': repair-table. or when
     creating indexes with *Note `CREATE INDEX': create-index. or *Note
     `ALTER TABLE': alter-table.

     The maximum permissible setting for `myisam_sort_buffer_size' is
     4GB.

   *  `myisam_stats_method'

     Options for myisam_stats_method      *Version Introduced* 5.0.14          
     *Command-Line        `--myisam_stats_method=name'        
     Format*                              
     *Option-File Format* `myisam_stats_method'        
     *Option Sets         Yes,            
     Variable*            `myisam_stats_method'        
     *Variable Name*      `myisam_stats_method'        
     *Variable Scope*     Global,         
                          Session         
     *Dynamic Variable*   Yes             
                          *Permitted        
                          Values          
                          (>=             
                          5.0)*           
     *Type*               `enumeration'        
     *Valid Values*       `nulls_equal'        
                          `nulls_unequal'        
                          `nulls_ignored'        


     How the server treats `NULL' values when collecting statistics
     about the distribution of index values for `MyISAM' tables. This
     variable has three possible values, `nulls_equal',
     `nulls_unequal', and `nulls_ignored'. For `nulls_equal', all `NULL'
     index values are considered equal and form a single value group
     that has a size equal to the number of `NULL' values. For
     `nulls_unequal', `NULL' values are considered unequal, and each
     `NULL' forms a distinct value group of size 1. For `nulls_ignored',
     `NULL' values are ignored.

     The method that is used for generating table statistics influences
     how the optimizer chooses indexes for query execution, as
     described in *Note myisam-index-statistics::.

     Any unique prefix of a valid value may be used to set the value of
     this variable.

     This variable was added in MySQL 5.0.14. For older versions, the
     statistics collection method is equivalent to `nulls_equal'.

   *  `named_pipe'

     Options for named_pipe      *Variable Name*      `named_pipe'        
     *Variable Scope*     Global          
     *Dynamic Variable*   No              
     *Platform Specific*  windows         
                          *Permitted        
                          Values          
                          *               
     *Type* (windows)     `boolean'        
     *Default*            `OFF'           


     (Windows only.) Indicates whether the server supports connections
     over named pipes.

   *  `net_buffer_length'

     Options for net_buffer_length      *Command-Line        `--net_buffer_length=#'        
     Format*                              
     *Option-File Format* `net_buffer_length'        
     *Option Sets         Yes,            
     Variable*            `net_buffer_length'        
     *Variable Name*      `net_buffer_length'        
     *Variable Scope*     Global,         
                          Session         
     *Dynamic Variable*   Yes             
                          *Permitted        
                          Values          
                          *               
     *Type*               `numeric'        
     *Default*            `16384'         
     *Range*              `1024           
                          ..              
                          1048576'        


     Each client thread is associated with a connection buffer and
     result buffer. Both begin with a size given by `net_buffer_length'
     but are dynamically enlarged up to `max_allowed_packet' bytes as
     needed. The result buffer shrinks to `net_buffer_length' after each
     SQL statement.

     This variable should not normally be changed, but if you have very
     little memory, you can set it to the expected length of statements
     sent by clients. If statements exceed this length, the connection
     buffer is automatically enlarged. The maximum value to which
     `net_buffer_length' can be set is 1MB.

     As of MySQL 5.0.84, the session value of this variable is read
     only. Before 5.0.84, setting the session value is permitted but
     has no effect.

   *  `net_read_timeout'

     Options for net_read_timeout      *Command-Line        `--net_read_timeout=#'        
     Format*                              
     *Option-File Format* `net_read_timeout'        
     *Option Sets         Yes,            
     Variable*            `net_read_timeout'        
     *Variable Name*      `net_read_timeout'        
     *Variable Scope*     Global,         
                          Session         
     *Dynamic Variable*   Yes             
                          *Permitted        
                          Values          
                          *               
     *Type*               `numeric'        
     *Default*            `30'            
     *Min Value*          `1'             


     The number of seconds to wait for more data from a connection
     before aborting the read. This timeout applies only to TCP/IP
     connections, not to connections made through Unix socket files,
     named pipes, or shared memory. When the server is reading from the
     client, `net_read_timeout' is the timeout value controlling when
     to abort. When the server is writing to the client,
     `net_write_timeout' is the timeout value controlling when to
     abort. See also `slave_net_timeout'.

     On Linux, the `NO_ALARM' build flag affects timeout behavior as
     indicated in the description of the `net_retry_count' system
     variable.

   *  `net_retry_count'

     Options for net_retry_count      *Command-Line        `--net_retry_count=#'        
     Format*                              
     *Option-File Format* `net_retry_count'        
     *Option Sets         Yes,            
     Variable*            `net_retry_count'        
     *Variable Name*      `net_retry_count'        
     *Variable Scope*     Global,         
                          Session         
     *Dynamic Variable*   Yes             
                          *Permitted        
                          Values          
                          *               
     *Platform Bit Size*  `32'            
     *Type*               `numeric'        
     *Default*            `10'            
     *Range*              `1 ..           
                          4294967295'        
                          *Permitted        
                          Values          
                          *               
     *Platform Bit Size*  `64'            
     *Type*               `numeric'        
     *Default*            `10'            
     *Range*              `1 ..           
                          18446744073709547520'        


     If a read or write on a communication port is interrupted, retry
     this many times before giving up. This value should be set quite
     high on FreeBSD because internal interrupts are sent to all
     threads.

     On Linux, the `NO_ALARM' build flag (`-DNO_ALARM') modifies how
     the binary treats both `net_read_timeout' and `net_write_timeout'.
     With this flag enabled, neither timer cancels the current statement
     until after the failing connection has been waited on an
     additional `net_retry_count' times. This means that the effective
     timeout value becomes `(timeout setting) x (net_retry_count+1)'.

   *  `net_write_timeout'

     Options for net_write_timeout      *Command-Line        `--net_write_timeout=#'        
     Format*                              
     *Option-File Format* `net_write_timeout'        
     *Option Sets         Yes,            
     Variable*            `net_write_timeout'        
     *Variable Name*      `net_write_timeout'        
     *Variable Scope*     Global,         
                          Session         
     *Dynamic Variable*   Yes             
                          *Permitted        
                          Values          
                          *               
     *Type*               `numeric'        
     *Default*            `60'            
     *Min Value*          `1'             


     The number of seconds to wait for a block to be written to a
     connection before aborting the write. This timeout applies only to
     TCP/IP connections, not to connections made using Unix socket
     files, named pipes, or shared memory. See also `net_read_timeout'.

     On Linux, the `NO_ALARM' build flag affects timeout behavior as
     indicated in the description of the `net_retry_count' system
     variable.

   *  `new'

     Options for new      *Command-Line        `--new'         
     Format*                              
     **                   `-n'            
     *Option-File Format* `new'           
     *Option Sets         Yes,            
     Variable*            `new'           
     *Variable Name*      `new'           
     *Variable Scope*     Global,         
                          Session         
     *Dynamic Variable*   Yes             
     *Disabled by*        `skip-new'        
                          *Permitted        
                          Values          
                          *               
     *Type*               `boolean'        
     *Default*            `FALSE'         


     This variable was used in MySQL 4.0 to turn on some 4.1 behaviors,
     and is retained for backward compatibility. In MySQL 5.0, its
     value is always `OFF'.

   *  `old_passwords'

     Options for old-passwords      *Command-Line        `--old_passwords'        
     Format*                              
     *Option-File Format* `old-passwords'        
     *Option Sets         Yes,            
     Variable*            `old_passwords'        
     *Variable Name*      `old_passwords'        
     *Variable Scope*     Global,         
                          Session         
     *Dynamic Variable*   Yes             
                          *Permitted        
                          Values          
                          *               
     *Type*               `boolean'        
     *Default*            `FALSE'         


     Whether the server should use pre-4.1-style passwords for MySQL
     user accounts. See *Note old-client::.

   *  `one_shot'

     This is not a variable, but it can be used when setting some
     variables. It is described in *Note set-option::.

   *  `open_files_limit'

     Options for open-files-limit      *Command-Line        `--open-files-limit=#'        
     Format*                              
     *Option-File Format* `open-files-limit'        
     *Option Sets         Yes,            
     Variable*            `open_files_limit'        
     *Variable Name*      `open_files_limit'        
     *Variable Scope*     Global          
     *Dynamic Variable*   No              
                          *Permitted        
                          Values          
                          *               
     *Type*               `numeric'        
     *Default*            `0'             
     *Range*              `0 ..           
                          65535'          


     The number of files that the operating system permits *Note
     `mysqld': mysqld. to open. This is the real value permitted by the
     system and might be different from the value you gave using the
     `--open-files-limit' option to *Note `mysqld': mysqld. or *Note
     `mysqld_safe': mysqld-safe.  The value is 0 on systems where MySQL
     cannot change the number of open files.

   *  `optimizer_prune_level'

     Options for optimizer_prune_level      *Version Introduced* 5.0.1           
     *Command-Line        `--optimizer_prune_level[=#]'        
     Format*                              
     *Option-File Format* `optimizer_prune_level'        
     *Option Sets         Yes,            
     Variable*            `optimizer_prune_level'        
     *Variable Name*      `optimizer_prune_level'        
     *Variable Scope*     Global,         
                          Session         
     *Dynamic Variable*   Yes             
                          *Permitted        
                          Values          
                          *               
     *Type*               `boolean'        
     *Default*            `1'             


     Controls the heuristics applied during query optimization to prune
     less-promising partial plans from the optimizer search space. A
     value of 0 disables heuristics so that the optimizer performs an
     exhaustive search. A value of 1 causes the optimizer to prune
     plans based on the number of rows retrieved by intermediate plans.
     This variable was added in MySQL 5.0.1.

   *  `optimizer_search_depth'

     Options for optimizer_search_depth      *Version Introduced* 5.0.1           
     *Command-Line        `--optimizer_search_depth[=#]'        
     Format*                              
     *Option-File Format* `optimizer_search_depth'        
     *Option Sets         Yes,            
     Variable*            `optimizer_search_depth'        
     *Variable Name*      `optimizer_search_depth'        
     *Variable Scope*     Global,         
                          Session         
     *Dynamic Variable*   Yes             
                          *Permitted        
                          Values          
                          *               
     *Type*               `numeric'        
     *Default*            `62'            


     The maximum depth of search performed by the query optimizer.
     Values larger than the number of relations in a query result in
     better query plans, but take longer to generate an execution plan
     for a query. Values smaller than the number of relations in a
     query return an execution plan quicker, but the resulting plan may
     be far from being optimal. If set to 0, the system automatically
     picks a reasonable value. If set to 63, the optimizer switches to
     the algorithm used in MySQL 5.0.0 (and previous versions) for
     performing searches. This variable was added in MySQL 5.0.1.

   *  `pid_file'

     Options for pid-file      *Command-Line        `--pid-file=file_name'        
     Format*                              
     *Option-File Format* `pid-file=file_name'        
     *Option Sets         Yes,            
     Variable*            `pid_file'        
     *Variable Name*      `pid_file'        
     *Variable Scope*     Global          
     *Dynamic Variable*   No              
                          *Permitted        
                          Values          
                          *               
     *Type*               `file           
                          name'           


     The path name of the process ID (PID) file. This variable can be
     set with the `--pid-file' option.

   *  `plugin_dir'

     Options for plugin_dir      *Version Introduced* 5.0.67          
     *Command-Line        `--plugin_dir=path'        
     Format*                              
     *Option-File Format* `plugin_dir'        
     *Option Sets         Yes,            
     Variable*            `plugin_dir'        
     *Variable Name*      `plugin_dir'        
     *Variable Scope*     Global          
     *Dynamic Variable*   No              


     The path name of the plugin directory. This variable was added in
     MySQL 5.0.67. If the value is nonempty, user-defined function
     object files must be located in this directory. If the value is
     empty, the behavior that is used before 5.0.67 applies: The UDF
     object files must be located in a directory that is searched by
     your system's dynamic linker.

     If the plugin directory is writable by the server, it may be
     possible for a user to write executable code to a file in the
     directory using *Note `SELECT ... INTO DUMPFILE': select. This can
     be prevented by making `plugin_dir' read only to the server or by
     setting `--secure-file-priv' to a directory where *Note `SELECT':
     select. writes can be made safely.

   *  `port'

     Options for port      *Command-Line        `--port=#'        
     Format*                              
     **                   `-P'            
     *Option-File Format* `port'          
     *Option Sets         Yes,            
     Variable*            `port'          
     *Variable Name*      `port'          
     *Variable Scope*     Global          
     *Dynamic Variable*   No              
                          *Permitted        
                          Values          
                          *               
     *Type*               `numeric'        
     *Default*            `3306'          


     The number of the port on which the server listens for TCP/IP
     connections. This variable can be set with the `--port' option.

   *  `preload_buffer_size'

     Options for preload_buffer_size      *Command-Line        `--preload_buffer_size=#'        
     Format*                              
     *Option-File Format* `preload_buffer_size'        
     *Option Sets         Yes,            
     Variable*            `preload_buffer_size'        
     *Variable Name*      `preload_buffer_size'        
     *Variable Scope*     Global,         
                          Session         
     *Dynamic Variable*   Yes             
                          *Permitted        
                          Values          
                          *               
     *Type*               `numeric'        
     *Default*            `32768'         
     *Range*              `1024           
                          ..              
                          1073741824'        


     The size of the buffer that is allocated when preloading indexes.

   *  `prepared_stmt_count'

     Options for prepared_stmt_count      *Version Introduced* 5.0.21          
     *Version Removed*    5.0.31          
     *Variable Name*      `prepared_stmt_count'        
     *Variable Scope*     Global          
     *Dynamic Variable*   No              
                          *Permitted        
                          Values          
                          *               
     *Type*               `numeric'        


     The current number of prepared statements. (The maximum number of
     statements is given by the `max_prepared_stmt_count' system
     variable.) This variable was added in MySQL 5.0.21. In MySQL
     5.0.32, it was converted to the global `Prepared_stmt_count' status
     variable.

   *  `profiling'

     If set to 0 (the default), statement profiling is disabled. If set
     to 1, statement profiling is enabled and the *Note `SHOW
     PROFILES': show-profiles. and *Note `SHOW PROFILE': show-profile.
     statements provide access to profiling information. See *Note
     show-profiles::. This variable was added in MySQL 5.0.37. _Note_:
     This option does not apply to MySQL Enterprise Server users.

   *  `profiling_history_size'

     The number of statements for which to maintain profiling
     information if `profiling' is enabled. The default value is 15.
     The maximum value is 100.  Setting the value to 0 effectively
     disables profiling. See *Note show-profiles::. This variable was
     added in MySQL 5.0.37. _Note_: This option does not apply to MySQL
     Enterprise Server users.

   *  `protocol_version'

     Options for protocol_version      *Variable Name*      `protocol_version'        
     *Variable Scope*     Global          
     *Dynamic Variable*   No              
                          *Permitted        
                          Values          
                          *               
     *Type*               `numeric'        


     The version of the client/server protocol used by the MySQL server.

   *  `pseudo_thread_id'

     Options for pseudo_thread_id      *Variable Name*      `pseudo_thread_id'        
     *Variable Scope*     Session         
     *Dynamic Variable*   Yes             
                          *Permitted        
                          Values          
                          *               
     *Type*               `numeric'        


     This variable is for internal server use.

   *  `query_alloc_block_size'

     Options for query_alloc_block_size      *Command-Line        `--query_alloc_block_size=#'        
     Format*                              
     *Option-File Format* `query_alloc_block_size'        
     *Option Sets         Yes,            
     Variable*            `query_alloc_block_size'        
     *Variable Name*      `query_alloc_block_size'        
     *Variable Scope*     Global,         
                          Session         
     *Dynamic Variable*   Yes             
                          *Permitted        
                          Values          
                          *               
     *Platform Bit Size*  `32'            
     *Type*               `numeric'        
     *Default*            `8192'          
     *Range*              `1024           
                          ..              
                          4294967295'        
     *Block Size*         `1024'          
                          *Permitted        
                          Values          
                          *               
     *Platform Bit Size*  `64'            
     *Type*               `numeric'        
     *Default*            `8192'          
     *Range*              `1024           
                          ..              
                          18446744073709547520'        
     *Block Size*         `1024'          


     The allocation size of memory blocks that are allocated for
     objects created during statement parsing and execution. If you
     have problems with memory fragmentation, it might help to increase
     this parameter.

   *  `query_cache_limit'

     Options for query_cache_limit      *Command-Line        `--query_cache_limit=#'        
     Format*                              
     *Option-File Format* `query_cache_limit'        
     *Option Sets         Yes,            
     Variable*            `query_cache_limit'        
     *Variable Name*      `query_cache_limit'        
     *Variable Scope*     Global          
     *Dynamic Variable*   Yes             
                          *Permitted        
                          Values          
                          *               
     *Platform Bit Size*  `32'            
     *Type*               `numeric'        
     *Default*            `1048576'        
     *Range*              `0 ..           
                          4294967295'        
                          *Permitted        
                          Values          
                          *               
     *Platform Bit Size*  `64'            
     *Type*               `numeric'        
     *Default*            `1048576'        
     *Range*              `0 ..           
                          18446744073709547520'        


     Do not cache results that are larger than this number of bytes.
     The default value is 1MB.

   *  `query_cache_min_res_unit'

     Options for query_cache_min_res_unit      *Command-Line        `--query_cache_min_res_unit=#'        
     Format*                              
     *Option-File Format* `query_cache_min_res_unit'        
     *Option Sets         Yes,            
     Variable*            `query_cache_min_res_unit'        
     *Variable Name*      `query_cache_min_res_unit'        
     *Variable Scope*     Global          
     *Dynamic Variable*   Yes             
                          *Permitted        
                          Values          
                          *               
     *Platform Bit Size*  `32'            
     *Type*               `numeric'        
     *Default*            `4096'          
     *Range*              `512            
                          ..              
                          4294967295'        
                          *Permitted        
                          Values          
                          *               
     *Platform Bit Size*  `64'            
     *Type*               `numeric'        
     *Default*            `4096'          
     *Range*              `512            
                          ..              
                          18446744073709547520'        


     The minimum size (in bytes) for blocks allocated by the query
     cache. The default value is 4096 (4KB). Tuning information for
     this variable is given in *Note query-cache-configuration::.

   *  `query_cache_size'

     Options for query_cache_size      *Command-Line        `--query_cache_size=#'        
     Format*                              
     *Option-File Format* `query_cache_size'        
     *Option Sets         Yes,            
     Variable*            `query_cache_size'        
     *Variable Name*      `query_cache_size'        
     *Variable Scope*     Global          
     *Dynamic Variable*   Yes             
                          *Permitted        
                          Values          
                          *               
     *Platform Bit Size*  `32'            
     *Type*               `numeric'        
     *Default*            `0'             
     *Range*              `0 ..           
                          4294967295'        
                          *Permitted        
                          Values          
                          *               
     *Platform Bit Size*  `64'            
     *Type*               `numeric'        
     *Default*            `0'             
     *Range*              `0 ..           
                          18446744073709547520'        


     The amount of memory allocated for caching query results. The
     default value is 0, which disables the query cache. The
     permissible values are multiples of 1024; other values are rounded
     down to the nearest multiple. Note that `query_cache_size' bytes of
     memory are allocated even if `query_cache_type' is set to 0.  See
     *Note query-cache-configuration::, for more information.

     The query cache needs a minimum size of about 40KB to allocate its
     structures. (The exact size depends on system architecture.) If
     you set the value of `query_cache_size' too small, a warning will
     occur, as described in *Note query-cache-configuration::.

   *  `query_cache_type'

     Options for query_cache_type      *Command-Line        `--query_cache_type=#'        
     Format*                              
     *Option-File Format* `query_cache_type'        
     *Option Sets         Yes,            
     Variable*            `query_cache_type'        
     *Variable Name*      `query_cache_type'        
     *Variable Scope*     Global,         
                          Session         
     *Dynamic Variable*   Yes             
                          *Permitted        
                          Values          
                          *               
     *Type*               `enumeration'        
     *Default*            `1'             
     *Valid Values*       `0' `1'         
                          `2'             


     Set the query cache type. Setting the `GLOBAL' value sets the type
     for all clients that connect thereafter. Individual clients can
     set the `SESSION' value to affect their own use of the query
     cache. Possible values are shown in the following table.

     Option     Description
     `0' or     Do not cache results in or retrieve results
     `OFF'      from the query cache. Note that this does not
                deallocate the query cache buffer.  To do
                that, you should set `query_cache_size' to 0.
     `1' or     Cache all cacheable query results except for
     `ON'       those that begin with `SELECT SQL_NO_CACHE'.
     `2' or     Cache results only for cacheable queries that
     `DEMAND'   begin with `SELECT SQL_CACHE'.

     This variable defaults to `ON'.

     Any unique prefix of a valid value may be used to set the value of
     this variable.

   *  `query_cache_wlock_invalidate'

     Options for query_cache_wlock_invalidate      *Command-Line        `--query_cache_wlock_invalidate'        
     Format*                              
     *Option-File Format* `query_cache_wlock_invalidate'        
     *Option Sets         Yes,            
     Variable*            `query_cache_wlock_invalidate'        
     *Variable Name*      `query_cache_wlock_invalidate'        
     *Variable Scope*     Global,         
                          Session         
     *Dynamic Variable*   Yes             
                          *Permitted        
                          Values          
                          *               
     *Type*               `boolean'        
     *Default*            `FALSE'         


     Normally, when one client acquires a `WRITE' lock on a `MyISAM'
     table, other clients are not blocked from issuing statements that
     read from the table if the query results are present in the query
     cache. Setting this variable to 1 causes acquisition of a `WRITE'
     lock for a table to invalidate any queries in the query cache that
     refer to the table. This forces other clients that attempt to
     access the table to wait while the lock is in effect.

   *  `query_prealloc_size'

     Options for query_prealloc_size      *Command-Line        `--query_prealloc_size=#'        
     Format*                              
     *Option-File Format* `query_prealloc_size'        
     *Option Sets         Yes,            
     Variable*            `query_prealloc_size'        
     *Variable Name*      `query_prealloc_size'        
     *Variable Scope*     Global,         
                          Session         
     *Dynamic Variable*   Yes             
                          *Permitted        
                          Values          
                          *               
     *Platform Bit Size*  `32'            
     *Type*               `numeric'        
     *Default*            `8192'          
     *Range*              `8192           
                          ..              
                          4294967295'        
     *Block Size*         `1024'          
                          *Permitted        
                          Values          
                          *               
     *Platform Bit Size*  `64'            
     *Type*               `numeric'        
     *Default*            `8192'          
     *Range*              `8192           
                          ..              
                          18446744073709547520'        
     *Block Size*         `1024'          


     The size of the persistent buffer used for statement parsing and
     execution. This buffer is not freed between statements. If you are
     running complex queries, a larger `query_prealloc_size' value
     might be helpful in improving performance, because it can reduce
     the need for the server to perform memory allocation during query
     execution operations.

   *  `rand_seed1'

     The `rand_seed1' and `rand_seed2' variables exist as session
     variables only, and can be set but not read. They are not shown in
     the output of *Note `SHOW VARIABLES': show-variables.

     The purpose of these variables is to support replication of the
     `RAND()' function. For statements that invoke `RAND()', the master
     passes two values to the slave, where they are used to seed the
     random number generator. The slave uses these values to set the
     session variables `rand_seed1' and `rand_seed2' so that `RAND()'
     on the slave generates the same value as on the master.

   *  `rand_seed2'

     See the description for `rand_seed1'.

   *  `range_alloc_block_size'

     Options for range_alloc_block_size      *Command-Line        `--range_alloc_block_size=#'        
     Format*                              
     *Option-File Format* `range_alloc_block_size'        
     *Option Sets         Yes,            
     Variable*            `range_alloc_block_size'        
     *Variable Name*      `range_alloc_block_size'        
     *Variable Scope*     Global,         
                          Session         
     *Dynamic Variable*   Yes             
                          *Permitted        
                          Values          
                          (>=             
                          5.0.54)*        
     *Platform Bit Size*  `32'            
     *Type*               `numeric'        
     *Default*            `4096'          
     *Range*              `4096           
                          ..              
                          4294967295'        
     *Block Size*         `1024'          
                          *Permitted        
                          Values          
                          (>=             
                          5.0.54)*        
     *Platform Bit Size*  `64'            
     *Type*               `numeric'        
     *Default*            `4096'          
     *Range*              `4096           
                          ..              
                          18446744073709547520'        
     *Block Size*         `1024'          


     The size of blocks that are allocated when doing range
     optimization.

   *  `read_buffer_size'

     Options for read_buffer_size      *Command-Line        `--read_buffer_size=#'        
     Format*                              
     *Option-File Format* `read_buffer_size'        
     *Option Sets         Yes,            
     Variable*            `read_buffer_size'        
     *Variable Name*      `read_buffer_size'        
     *Variable Scope*     Global,         
                          Session         
     *Dynamic Variable*   Yes             
                          *Permitted        
                          Values          
                          *               
     *Type*               `numeric'        
     *Default*            `131072'        
     *Range*              `8200           
                          ..              
                          2147479552'        


     Each thread that does a sequential scan allocates a buffer of this
     size (in bytes) for each table it scans. If you do many sequential
     scans, you might want to increase this value, which defaults to
     131072. The value of this variable should be a multiple of 4KB. If
     it is set to a value that is not a multiple of 4KB, its value will
     be rounded down to the nearest multiple of 4KB.

     The maximum permissible setting for `read_buffer_size' is 2GB.

     `read_buffer_size' and `read_rnd_buffer_size' are not specific to
     any storage engine and apply in a general manner for optimization.
     See *Note memory-use::, for example.

   *  `read_only'

     Options for read_only      *Command-Line        `--read-only'        
     Format*                              
     *Option-File Format* `read_only'        
     *Option Sets         Yes,            
     Variable*            `read_only'        
     *Variable Name*      `read_only'        
     *Variable Scope*     Global          
     *Dynamic Variable*   Yes             
                          *Permitted        
                          Values          
                          *               
     *Type*               `numeric'        
     *Default*            `0'             


     This variable is off by default. When it is enabled, the server
     permits no updates except from users that have the `SUPER'
     privilege or (on a slave server) from updates performed by slave
     threads. In replication setups, it can be useful to enable
     `read_only' on slave servers to ensure that slaves accept updates
     only from the master server and not from clients.

     `read_only' does not apply to `TEMPORARY' tables as of MySQL
     5.0.16. This variable does not prevent the use of *Note `ANALYZE
     TABLE': analyze-table. or *Note `OPTIMIZE TABLE': optimize-table.
     statements because its purpose is to prevent changes to table
     structure or contents. Analysis and optimization do not qualify as
     such changes. This means, for example, that consistency checks on
     read-only slaves can be performed with *Note `mysqlcheck
     --all-databases --analyze': mysqlcheck.

     `read_only' exists only as a `GLOBAL' variable, so changes to its
     value require the `SUPER' privilege.  Changes to `read_only' on a
     master server are not replicated to slave servers. The value can
     be set on a slave server independent of the setting on the master.

     *Important*:

     In MySQL 5.0, enabling `read_only' does _not_ prevent the use of
     the *Note `SET PASSWORD': set-password. statement. This is not
     necessarily the case for all MySQL release series.  When
     replicating from one MySQL release series to another (for example,
     from a MySQL 5.0 master to a MySQL 5.1 slave), you should check
     the documentation for the versions running on both master and
     slave to determine whether the behavior of `read_only' in this
     regard is or is not the same, and, if it is different, whether
     this has an impact on your applications.

   *  `read_rnd_buffer_size'

     Options for read_rnd_buffer_size      *Command-Line        `--read_rnd_buffer_size=#'        
     Format*                              
     *Option-File Format* `read_rnd_buffer_size'        
     *Option Sets         Yes,            
     Variable*            `read_rnd_buffer_size'        
     *Variable Name*      `read_rnd_buffer_size'        
     *Variable Scope*     Global,         
                          Session         
     *Dynamic Variable*   Yes             
                          *Permitted        
                          Values          
                          *               
     *Type*               `numeric'        
     *Default*            `262144'        
     *Range*              `8200           
                          ..              
                          4294967295'        


     When reading rows in sorted order following a key-sorting
     operation, the rows are read through this buffer to avoid disk
     seeks. See *Note order-by-optimization::. Setting the variable to
     a large value can improve `ORDER BY' performance by a lot.
     However, this is a buffer allocated for each client, so you should
     not set the global variable to a large value. Instead, change the
     session variable only from within those clients that need to run
     large queries.

     The maximum permissible setting for `read_rnd_buffer_size' is 2GB.

     `read_buffer_size' and `read_rnd_buffer_size' are not specific to
     any storage engine and apply in a general manner for optimization.
     See *Note memory-use::, for example.

   *  `relay_log_purge'

     Options for relay_log_purge      *Command-Line        `--relay_log_purge'        
     Format*                              
     *Option-File Format* `relay_log_purge'        
     *Option Sets         Yes,            
     Variable*            `relay_log_purge'        
     *Variable Name*      `relay_log_purge'        
     *Variable Scope*     Global          
     *Dynamic Variable*   Yes             
                          *Permitted        
                          Values          
                          *               
     *Type*               `boolean'        
     *Default*            `TRUE'          


     Disables or enables automatic purging of relay log files as soon
     as they are not needed any more. The default value is 1 (`ON').

   *  `relay_log_space_limit'

     Options for relay_log_space_limit      *Command-Line        `--relay_log_space_limit=#'        
     Format*                              
     *Option-File Format* `relay_log_space_limit'        
     *Option Sets         Yes,            
     Variable*            `relay_log_space_limit'        
     *Variable Name*      `relay_log_space_limit'        
     *Variable Scope*     Global          
     *Dynamic Variable*   No              
                          *Permitted        
                          Values          
                          *               
     *Platform Bit Size*  `32'            
     *Type*               `numeric'        
     *Default*            `0'             
     *Range*              `0 ..           
                          4294967295'        
                          *Permitted        
                          Values          
                          *               
     *Platform Bit Size*  `64'            
     *Type*               `numeric'        
     *Default*            `0'             
     *Range*              `0 ..           
                          18446744073709547520'        


     The maximum amount of space to use for all relay logs.

   *  `secure_auth'

     Options for secure-auth      *Command-Line        `--secure-auth'        
     Format*                              
     *Option-File Format* `secure-auth'        
     *Option Sets         Yes,            
     Variable*            `secure_auth'        
     *Variable Name*      `secure_auth'        
     *Variable Scope*     Global          
     *Dynamic Variable*   Yes             
                          *Permitted        
                          Values          
                          *               
     *Type*               `boolean'        
     *Default*            `FALSE'         


     If the MySQL server has been started with the `--secure-auth'
     option, it blocks connections from all accounts that have
     passwords stored in the old (pre-4.1) format. In that case, the
     value of this variable is `ON', otherwise it is `OFF'.

     You should enable this option if you want to prevent all use of
     passwords employing the old format (and hence insecure
     communication over the network).

     Server startup fails with an error if this option is enabled and
     the privilege tables are in pre-4.1 format. See *Note old-client::.

   *  `secure_file_priv'

     Options for secure-file-priv      *Version Introduced* 5.0.38          
     *Command-Line        `--secure-file-priv=path'        
     Format*                              
     *Option-File Format* `secure-file-priv=path'        
     *Option Sets         Yes,            
     Variable*            `secure_file_priv'        
     *Variable Name*      `secure-file-priv'        
     *Variable Scope*     Global          
     *Dynamic Variable*   No              
                          *Permitted        
                          Values          
                          *               
     *Type*               `string'        


     By default, this variable is empty. If set to the name of a
     directory, it limits the effect of the `LOAD_FILE()' function and
     the *Note `LOAD DATA': load-data. and *Note `SELECT ... INTO
     OUTFILE': select-into. statements to work only with files in that
     directory.

     This variable was added in MySQL 5.0.38.

   *  `server_id'

     Options for server-id      *Command-Line        `--server-id=#'        
     Format*                              
     *Option-File Format* `server-id'        
     *Option Sets         Yes,            
     Variable*            `server_id'        
     *Variable Name*      `server_id'        
     *Variable Scope*     Global          
     *Dynamic Variable*   Yes             
                          *Permitted        
                          Values          
                          *               
     *Type*               `numeric'        
     *Default*            `0'             
     *Range*              `0 ..           
                          4294967295'        


     The server ID, used in replication to give each master and slave a
     unique identity. This variable is set by the `--server-id' option.
     For each server participating in replication, you should pick a
     positive integer in the range from 1 to 2^32 - 1 to act as that
     server's ID.

   *  `shared_memory'

     Options for shared_memory      *Variable Name*      `shared_memory'        
     *Variable Scope*     Global          
     *Dynamic Variable*   No              
     *Platform Specific*  windows         


     (Windows only.) Whether the server permits shared-memory
     connections.

   *  `shared_memory_base_name'

     Options for shared_memory_base_name      *Variable Name*      `shared_memory_base_name'        
     *Variable Scope*     Global          
     *Dynamic Variable*   No              
     *Platform Specific*  windows         


     (Windows only.) The name of shared memory to use for shared-memory
     connections. This is useful when running multiple MySQL instances
     on a single physical machine. The default name is `MYSQL'. The
     name is case sensitive.

   *  `skip_external_locking'

     This is `OFF' if *Note `mysqld': mysqld.  uses external locking,
     `ON' if external locking is disabled. This affects only *Note
     `MyISAM': myisam-storage-engine. table access.

   *  `skip_networking'

     This is `ON' if the server permits only local (non-TCP/IP)
     connections. On Unix, local connections use a Unix socket file. On
     Windows, local connections use a named pipe or shared memory. On
     NetWare, only TCP/IP connections are supported, so do not set this
     variable to `ON'. This variable can be set to `ON' with the
     `--skip-networking' option.

   *  `skip_show_database'

     This prevents people from using the *Note `SHOW DATABASES':
     show-databases. statement if they do not have the `SHOW DATABASES'
     privilege. This can improve security if you have concerns about
     users being able to see databases belonging to other users. Its
     effect depends on the `SHOW DATABASES' privilege: If the variable
     value is `ON', the *Note `SHOW DATABASES': show-databases.
     statement is permitted only to users who have the `SHOW DATABASES'
     privilege, and the statement displays all database names. If the
     value is `OFF', *Note `SHOW DATABASES': show-databases. is
     permitted to all users, but displays the names of only those
     databases for which the user has the `SHOW DATABASES' or other
     privilege.

   *  `slow_launch_time'

     Options for slow_launch_time      *Command-Line        `--slow_launch_time=#'        
     Format*                              
     *Option-File Format* `slow_launch_time'        
     *Option Sets         Yes,            
     Variable*            `slow_launch_time'        
     *Variable Name*      `slow_launch_time'        
     *Variable Scope*     Global          
     *Dynamic Variable*   Yes             
                          *Permitted        
                          Values          
                          *               
     *Type*               `numeric'        
     *Default*            `2'             


     If creating a thread takes longer than this many seconds, the
     server increments the `Slow_launch_threads' status variable.

   *  `socket'

     Options for socket      *Command-Line        `--socket=name'        
     Format*                              
     *Option-File Format* `socket'        
     *Option Sets         Yes,            
     Variable*            `socket'        
     *Variable Name*      `socket'        
     *Variable Scope*     Global          
     *Dynamic Variable*   No              
                          *Permitted        
                          Values          
                          *               
     *Type*               `file           
                          name'           
     *Default*            `/tmp/mysql.sock'        


     On Unix platforms, this variable is the name of the socket file
     that is used for local client connections. The default is
     `/tmp/mysql.sock'. (For some distribution formats, the directory
     might be different, such as `/var/lib/mysql' for RPMs.)

     On Windows, this variable is the name of the named pipe that is
     used for local client connections. The default value is `MySQL'
     (not case sensitive).

   *  `sort_buffer_size'

     Options for sort_buffer_size      *Command-Line        `--sort_buffer_size=#'        
     Format*                              
     *Option-File Format* `sort_buffer_size'        
     *Option Sets         Yes,            
     Variable*            `sort_buffer_size'        
     *Variable Name*      `sort_buffer_size'        
     *Variable Scope*     Global,         
                          Session         
     *Dynamic Variable*   Yes             
                          *Permitted        
                          Values          
                          *               
     *Platform Bit Size*  `32'            
     *Type*               `numeric'        
     *Default*            `2097144'        
     *Max Value*          `4294967295'        
                          *Permitted        
                          Values          
                          *               
     *Platform Bit Size*  `64'            
     *Type*               `numeric'        
     *Default*            `2097144'        
     *Max Value*          `18446744073709547520'        


     Each session that needs to do a sort allocates a buffer of this
     size. `sort_buffer_size' is not specific to any storage engine and
     applies in a general manner for optimization. See *Note
     order-by-optimization::, for example.

     If you see many `Sort_merge_passes' per second in *Note `SHOW
     GLOBAL STATUS': show-status. output, you can consider increasing
     the `sort_buffer_size' value to speed up `ORDER BY' or `GROUP BY'
     operations that cannot be improved with query optimization or
     improved indexing. The entire buffer is allocated even if it is
     not all needed, so setting it larger than required globally will
     slow down most queries that sort.  It is best to increase it as a
     session setting, and only for the sessions that need a larger
     size. On Linux, there are thresholds of 256KB and 2MB where larger
     values may significantly slow down memory allocation, so you should
     consider staying below one of those values. Experiment to find the
     best value for your workload. See *Note temporary-files::.

     The maximum permissible setting for `sort_buffer_size' is 4GB.

   *  `sql_auto_is_null'

     Options for sql_auto_is_null      *Variable Name*      `sql_auto_is_null'        
     *Variable Scope*     Session         
     *Dynamic Variable*   Yes             


     If this variable is set to 1 (the default), then after a statement
     that successfully inserts an automatically generated
     `AUTO_INCREMENT' value, you can find that value by issuing a
     statement of the following form:

          SELECT * FROM TBL_NAME WHERE AUTO_COL IS NULL

     If the statement returns a row, the value returned is the same as
     if you invoked the `LAST_INSERT_ID()' function. For details,
     including the return value after a multiple-row insert, see *Note
     information-functions::. If no `AUTO_INCREMENT' value was
     successfully inserted, the *Note `SELECT': select. statement
     returns no row.

     The behavior of retrieving an `AUTO_INCREMENT' value by using an
     `IS NULL' comparison is used by some ODBC programs, such as
     Access. See *Note
     connector-odbc-usagenotes-functionality-last-insert-id::.  This
     behavior can be disabled by setting `sql_auto_is_null' to 0.

   *  `sql_big_selects'

     Options for sql_big_selects      *Variable Name*      `sql_big_selects'        
     *Variable Scope*     Session         
     *Dynamic Variable*   Yes             
                          *Permitted        
                          Values          
                          *               
     *Type*               `boolean'        
     *Default*            `1'             


     If set to 0, MySQL aborts *Note `SELECT': select. statements that
     are likely to take a very long time to execute (that is,
     statements for which the optimizer estimates that the number of
     examined rows exceeds the value of `max_join_size'). This is
     useful when an inadvisable `WHERE' statement has been issued. The
     default value for a new connection is 1, which permits all *Note
     `SELECT': select.  statements.

     If you set the `max_join_size' system variable to a value other
     than `DEFAULT', `sql_big_selects' is set to 0.

   *  `sql_buffer_result'

     Options for sql_buffer_result      *Variable Name*      `sql_buffer_result'        
     *Variable Scope*     Session         
     *Dynamic Variable*   Yes             
                          *Permitted        
                          Values          
                          *               
     *Type*               `boolean'        
     *Default*            `0'             


     If set to 1, `sql_buffer_result' forces results from *Note
     `SELECT': select. statements to be put into temporary tables. This
     helps MySQL free the table locks early and can be beneficial in
     cases where it takes a long time to send results to the client.
     The default value is 0.

   *  `sql_log_bin'

     Options for sql_log_bin      *Variable Name*      `sql_log_bin'        
     *Variable Scope*     Session         
     *Dynamic Variable*   Yes             
                          *Permitted        
                          Values          
                          *               
     *Type*               `boolean'        


     If set to 0, no logging is done to the binary log for the client.
     The client must have the `SUPER' privilege to set this option. The
     default value is 1.

   *  `sql_log_off'

     Options for sql_log_off      *Variable Name*      `sql_log_off'        
     *Variable Scope*     Session         
     *Dynamic Variable*   Yes             
                          *Permitted        
                          Values          
                          *               
     *Type*               `boolean'        
     *Default*            `0'             


     If set to 1, no logging is done to the general query log for this
     client. The client must have the `SUPER' privilege to set this
     option. The default value is 0.

   *  `sql_log_update'

     Options for sql_log_update      *Version Deprecated* 5.0             
     *Variable Name*      `sql_log_update'        
     *Variable Scope*     Session         
     *Dynamic Variable*   Yes             
     *Deprecated*         5.0,            
                          by              
                          `sql_log_bin'        
                          *Permitted        
                          Values          
                          *               
     *Type*               `boolean'        


     This variable is deprecated, and is mapped to `sql_log_bin'. It is
     removed in MySQL 5.5.

   *  `sql_mode'

     Options for sql-mode      *Command-Line        `--sql-mode=name'        
     Format*                              
     *Option-File Format* `sql-mode'        
     *Option Sets         Yes,            
     Variable*            `sql_mode'        
     *Variable Name*      `sql_mode'        
     *Variable Scope*     Global,         
                          Session         
     *Dynamic Variable*   Yes             
                          *Permitted        
                          Values          
                          *               
     *Type*               `set'           
     *Default*            `'''            
     *Valid Values*       `ALLOW_INVALID_DATES'        
                          `ANSI_QUOTES'        
                          `ERROR_FOR_DIVISION_BY_ZERO'        
                          `HIGH_NOT_PRECEDENCE'        
                          `IGNORE_SPACE'        
                          `NO_AUTO_CREATE_USER'        
                          `NO_AUTO_VALUE_ON_ZERO'        
                          `NO_BACKSLASH_ESCAPES'        
                          `NO_DIR_IN_CREATE'        
                          `NO_ENGINE_SUBSTITUTION'        
                          `NO_FIELD_OPTIONS'        
                          `NO_KEY_OPTIONS'        
                          `NO_TABLE_OPTIONS'        
                          `NO_UNSIGNED_SUBTRACTION'        
                          `NO_ZERO_DATE'        
                          `NO_ZERO_IN_DATE'        
                          `ONLY_FULL_GROUP_BY'        
                          `PAD_CHAR_TO_FULL_LENGTH'        
                          `PIPES_AS_CONCAT'        
                          `REAL_AS_FLOAT'        
                          `STRICT_ALL_TABLES'        
                          `STRICT_TRANS_TABLES'        


     The current server SQL mode, which can be set dynamically. See
     *Note server-sql-mode::.

   *  `sql_notes'

     If set to 1 (the default), warnings of `Note' level increment
     `warning_count' and the server records them. If set to 0, `Note'
     warnings do not increment `warning_count' and the server does not
     record them. *Note `mysqldump': mysqldump. includes output to set
     this variable to 0 so that reloading the dump file does not
     produce warnings for events that do not affect the integrity of
     the reload operation.  `sql_notes' was added in MySQL 5.0.3.

   *  `sql_quote_show_create'

     If set to 1 (the default), the server quotes identifiers for *Note
     `SHOW CREATE TABLE': show-create-table. and *Note `SHOW CREATE
     DATABASE': show-create-database.  statements. If set to 0, quoting
     is disabled. This option is enabled by default so that replication
     works for identifiers that require quoting. See *Note
     show-create-table::, and *Note show-create-database::.

   *  `sql_safe_updates'

     If set to 1, MySQL aborts *Note `UPDATE': update. or *Note
     `DELETE': delete. statements that do not use a key in the `WHERE'
     clause or a `LIMIT' clause. This makes it possible to catch *Note
     `UPDATE': update. or *Note `DELETE': delete. statements where keys
     are not used properly and that would probably change or delete a
     large number of rows. The default value is 0.

   *  `sql_select_limit'

     Options for sql_select_limit      *Variable Name*      `sql_select_limit'        
     *Variable Scope*     Global,         
                          Session         
     *Dynamic Variable*   Yes             
                          *Permitted        
                          Values          
                          *               
     *Type*               `numeric'        


     The maximum number of rows to return from *Note `SELECT': select.
     statements. The default value for a new connection is the maximum
     number of rows that the server permits per table, which depends on
     the server configuration and may be affected if the server build
     was configured with `--with-big-tables'. Typical default values
     are (2^32)-1 or (2^64)-1. If you have changed the limit, the
     default value can be restored by assigning a value of `DEFAULT'.

     If a *Note `SELECT': select. has a `LIMIT' clause, the `LIMIT'
     takes precedence over the value of `sql_select_limit'.

     `sql_select_limit' does not apply to *Note `SELECT': select.
     statements executed within stored routines. It also does not apply
     to *Note `SELECT': select. statements that do not produce a result
     set to be returned to the client. These include *Note `SELECT':
     select. statements in subqueries, *Note `CREATE TABLE ... SELECT':
     create-table, and *Note `INSERT INTO ... SELECT': insert-select.

   *  `sql_warnings'

     This variable controls whether single-row *Note `INSERT': insert.
     statements produce an information string if warnings occur. The
     default is 0. Set the value to 1 to produce an information string.

   *  `ssl_ca'

     Options for ssl-ca      *Version Introduced* 5.0.23          
     *Command-Line        `--ssl-ca=name'        
     Format*                              
     *Option-File Format* `ssl-ca'        
     *Option Sets         Yes,            
     Variable*            `ssl_ca'        
     *Variable Name*      `ssl-ca'        
     *Variable Scope*     Global          
     *Dynamic Variable*   No              
                          *Permitted        
                          Values          
                          *               
     *Type*               `file           
                          name'           


     The path to a file with a list of trusted SSL CAs. This variable
     was added in MySQL 5.0.23.

   *  `ssl_capath'

     Options for ssl-capath      *Version Introduced* 5.0.23          
     *Command-Line        `--ssl-capath=name'        
     Format*                              
     *Option-File Format* `ssl-capath'        
     *Option Sets         Yes,            
     Variable*            `ssl_capath'        
     *Variable Name*      `ssl-capath'        
     *Variable Scope*     Global          
     *Dynamic Variable*   No              
                          *Permitted        
                          Values          
                          *               
     *Type*               `directory        
                          name'           


     The path to a directory that contains trusted SSL CA certificates
     in PEM format. This variable was added in MySQL 5.0.23.

   *  `ssl_cert'

     Options for ssl-cert      *Version Introduced* 5.0.23          
     *Command-Line        `--ssl-cert=name'        
     Format*                              
     *Option-File Format* `ssl-cert'        
     *Option Sets         Yes,            
     Variable*            `ssl_cert'        
     *Variable Name*      `ssl-cert'        
     *Variable Scope*     Global          
     *Dynamic Variable*   No              
                          *Permitted        
                          Values          
                          *               
     *Type*               `file           
                          name'           


     The name of the SSL certificate file to use for establishing a
     secure connection. This variable was added in MySQL 5.0.23.

   *  `ssl_cipher'

     Options for ssl-cipher      *Version Introduced* 5.0.23          
     *Command-Line        `--ssl-cipher=name'        
     Format*                              
     *Option-File Format* `ssl-cipher'        
     *Option Sets         Yes,            
     Variable*            `ssl_cipher'        
     *Variable Name*      `ssl-cipher'        
     *Variable Scope*     Global          
     *Dynamic Variable*   No              
                          *Permitted        
                          Values          
                          *               
     *Type*               `file           
                          name'           


     A list of permissible ciphers to use for SSL encryption. This
     variable was added in MySQL 5.0.23.

   *  `ssl_key'

     Options for ssl-key      *Version Introduced* 5.0.23          
     *Command-Line        `--ssl-key=name'        
     Format*                              
     *Option-File Format* `ssl-key'        
     *Option Sets         Yes,            
     Variable*            `ssl_key'        
     *Variable Name*      `ssl-key'        
     *Variable Scope*     Global          
     *Dynamic Variable*   No              
                          *Permitted        
                          Values          
                          *               
     *Type*               `string'        


     The name of the SSL key file to use for establishing a secure
     connection. This variable was added in MySQL 5.0.23.

   *  `storage_engine'

     Options for storage_engine      *Variable Name*      `storage_engine'        
     *Variable Scope*     Global,         
                          Session         
     *Dynamic Variable*   Yes             


     The default storage engine (table type). To set the storage engine
     at server startup, use the `--default-storage-engine' option. See
     *Note server-options::.

   *  `sync_frm'

     Options for sync_frm      *Command-Line        `--sync-frm'        
     Format*                              
     *Option-File Format* `sync_frm'        
     *Option Sets         Yes,            
     Variable*            `sync_frm'        
     *Variable Name*      `sync_frm'        
     *Variable Scope*     Global          
     *Dynamic Variable*   Yes             
                          *Permitted        
                          Values          
                          *               
     *Type*               `boolean'        
     *Default*            `TRUE'          


     If this variable is set to 1, when any nontemporary table is
     created its `.frm' file is synchronized to disk (using
     `fdatasync()'). This is slower but safer in case of a crash. The
     default is 1.

   *  `system_time_zone'

     Options for system_time_zone      *Variable Name*      `system_time_zone'        
     *Variable Scope*     Global          
     *Dynamic Variable*   No              
                          *Permitted        
                          Values          
                          *               
     *Type*               `string'        


     The server system time zone. When the server begins executing, it
     inherits a time zone setting from the machine defaults, possibly
     modified by the environment of the account used for running the
     server or the startup script. The value is used to set
     `system_time_zone'.  Typically the time zone is specified by the
     `TZ' environment variable. It also can be specified using the
     `--timezone' option of the *Note `mysqld_safe': mysqld-safe.
     script.

     The `system_time_zone' variable differs from `time_zone'.
     Although they might have the same value, the latter variable is
     used to initialize the time zone for each client that connects.
     See *Note time-zone-support::.

   *  `table_cache'

     Options for table_cache      *Command-Line        `--table_cache=#'        
     Format*                              
     *Option-File Format* `table_cache'        
     *Option Sets         Yes,            
     Variable*            `table_cache'        
     *Variable Name*      `table_cache'        
     *Variable Scope*     Global          
     *Dynamic Variable*   Yes             
     *Deprecated*         5.1.3,          
                          by              
                          `table_open_cache'        
                          *Permitted        
                          Values          
                          *               
     *Type*               `numeric'        
     *Default*            `64'            
     *Range*              `1 ..           
                          524288'         


     The number of open tables for all threads. Increasing this value
     increases the number of file descriptors that *Note `mysqld':
     mysqld. requires. You can check whether you need to increase the
     table cache by checking the `Opened_tables' status variable. See
     *Note server-status-variables::. If the value of `Opened_tables'
     is large and you do not use *Note `FLUSH TABLES': flush.  often
     (which just forces all tables to be closed and reopened), then you
     should increase the value of the `table_cache' variable. For more
     information about the table cache, see *Note table-cache::.

   *  `table_lock_wait_timeout'

     Options for table_lock_wait_timeout      *Version Introduced* 5.0.10          
     *Command-Line        `--table_lock_wait_timeout=#'        
     Format*                              
     *Option-File Format* `table_lock_wait_timeout'        
     *Option Sets         Yes,            
     Variable*            `table_lock_wait_timeout'        
     *Variable Name*      `table_lock_wait_timeout'        
     *Variable Scope*     Global          
     *Dynamic Variable*   Yes             
                          *Permitted        
                          Values          
                          *               
     *Type*               `numeric'        
     *Default*            `50'            
     *Range*              `1 ..           
                          1073741824'        


     This variable is unused.

   *  `table_type'

     Options for table_type      *Variable Name*      `table_type'        
     *Variable Scope*     Global,         
                          Session         
     *Dynamic Variable*   Yes             
     *Deprecated*         5.2.5,          
                          by              
                          `storage_engine'        
                          *Permitted        
                          Values          
                          *               
     *Type*               `enumeration'        


     This variable is a synonym for `storage_engine'. In MySQL 5.0,
     `storage_engine' is the preferred name; `table_type' is deprecated
     and is removed in MySQL 5.5.

   *  `thread_cache_size'

     Options for thread_cache_size      *Command-Line        `--thread_cache_size=#'        
     Format*                              
     *Option-File Format* `thread_cache_size'        
     *Option Sets         Yes,            
     Variable*            `thread_cache_size'        
     *Variable Name*      `thread_cache_size'        
     *Variable Scope*     Global          
     *Dynamic Variable*   Yes             
                          *Permitted        
                          Values          
                          *               
     *Type*               `numeric'        
     *Default*            `0'             
     *Range*              `0 ..           
                          16384'          


     How many threads the server should cache for reuse. When a client
     disconnects, the client's threads are put in the cache if there
     are fewer than `thread_cache_size' threads there. Requests for
     threads are satisfied by reusing threads taken from the cache if
     possible, and only when the cache is empty is a new thread
     created. This variable can be increased to improve performance if
     you have a lot of new connections.  Normally, this does not
     provide a notable performance improvement if you have a good
     thread implementation. However, if your server sees hundreds of
     connections per second you should normally set `thread_cache_size'
     high enough so that most new connections use cached threads. By
     examining the difference between the `Connections' and
     `Threads_created' status variables, you can see how efficient the
     thread cache is. For details, see *Note server-status-variables::.

   *  `thread_concurrency'

     Options for thread_concurrency      *Command-Line        `--thread_concurrency=#'        
     Format*                              
     *Option-File Format* `thread_concurrency'        
     *Option Sets         Yes,            
     Variable*            `thread_concurrency'        
     *Variable Name*      `thread_concurrency'        
     *Variable Scope*     Global          
     *Dynamic Variable*   No              
     *Deprecated*         5.6.1           
                          *Permitted        
                          Values          
                          *               
     *Type*               `numeric'        
     *Default*            `10'            
     *Range*              `1 ..           
                          512'            


     This variable is specific to Solaris systems, for which *Note
     `mysqld': mysqld. invokes the `thr_setconcurrency()' with the
     variable value. This function enables applications to give the
     threads system a hint about the desired number of threads that
     should be run at the same time.

   *  `thread_stack'

     Options for thread_stack      *Command-Line        `--thread_stack=#'        
     Format*                              
     *Option-File Format* `thread_stack'        
     *Option Sets         Yes,            
     Variable*            `thread_stack'        
     *Variable Name*      `thread_stack'        
     *Variable Scope*     Global          
     *Dynamic Variable*   No              
                          *Permitted        
                          Values          
                          *               
     *Platform Bit Size*  `32'            
     *Type*               `numeric'        
     *Default*            `196608'        
     *Range*              `131072         
                          ..              
                          4294967295'        
     *Block Size*         `1024'          
                          *Permitted        
                          Values          
                          *               
     *Platform Bit Size*  `64'            
     *Type*               `numeric'        
     *Default*            `262144'        
     *Range*              `131072         
                          ..              
                          18446744073709547520'        
     *Block Size*         `1024'          


     The stack size for each thread. Many of the limits detected by the
     `crash-me' test are dependent on this value. See *Note
     mysql-benchmarks::. The default of 192KB (256KB for 64-bit
     systems) is large enough for normal operation. If the thread stack
     size is too small, it limits the complexity of the SQL statements
     that the server can handle, the recursion depth of stored
     procedures, and other memory-consuming actions.

   *  `time_format'

     This variable is unused.

   *  `time_zone'

     Options for time_zone      *Command-Line        `--default_time_zone=string'        
     Format*                              
     *Option-File Format* `default_time_zone'        
     *Variable Name*      `time_zone'        
     *Variable Scope*     Global,         
                          Session         
     *Dynamic Variable*   Yes             
                          *Permitted        
                          Values          
                          *               
     *Type*               `string'        


     The current time zone. This variable is used to initialize the
     time zone for each client that connects. By default, the initial
     value of this is `'SYSTEM'' (which means, `use the value of
     `system_time_zone'').  The value can be specified explicitly at
     server startup with the `--default-time-zone' option.  See *Note
     time-zone-support::.

   *  `timed_mutexes'

     Options for timed_mutexes      *Version Introduced* 5.0.3           
     *Command-Line        `--timed_mutexes'        
     Format*                              
     *Option-File Format* `timed_mutexes'        
     *Option Sets         Yes,            
     Variable*            `timed_mutexes'        
     *Variable Name*      `timed_mutexes'        
     *Variable Scope*     Global          
     *Dynamic Variable*   Yes             
                          *Permitted        
                          Values          
                          *               
     *Type*               `boolean'        
     *Default*            `OFF'           


     This variable controls whether `InnoDB' mutexes are timed. If this
     variable is set to 0 or `OFF' (the default), mutex timing is
     disabled. If the variable is set to 1 or `ON', mutex timing is
     enabled. With timing enabled, the `os_wait_times' value in the
     output from *Note `SHOW ENGINE INNODB MUTEX': show-engine.
     indicates the amount of time (in ms) spent in operating system
     waits. Otherwise, the value is 0. This variable was added in MySQL
     5.0.3.

   *  `timestamp = {TIMESTAMP_VALUE | DEFAULT}'

     Set the time for this client. This is used to get the original
     timestamp if you use the binary log to restore rows.
     TIMESTAMP_VALUE should be a Unix epoch timestamp, not a MySQL
     timestamp.

     `SET timestamp' affects the value returned by `NOW()' but not by
     `SYSDATE()'. This means that timestamp settings in the binary log
     have no effect on invocations of `SYSDATE()'. The server can be
     started with the `--sysdate-is-now' option to cause `SYSDATE()' to
     be an alias for `NOW()', in which case `SET timestamp' affects
     both functions.

   *  `tmp_table_size'

     Options for tmp_table_size      *Command-Line        `--tmp_table_size=#'        
     Format*                              
     *Option-File Format* `tmp_table_size'        
     *Option Sets         Yes,            
     Variable*            `tmp_table_size'        
     *Variable Name*      `tmp_table_size'        
     *Variable Scope*     Global,         
                          Session         
     *Dynamic Variable*   Yes             
                          *Permitted        
                          Values          
                          *               
     *Type*               `numeric'        
     *Default*            `system         
                          dependent'        
     *Range*              `1024           
                          ..              
                          4294967295'        


     The maximum size of internal in-memory temporary tables. (The
     actual limit is determined as the minimum of `tmp_table_size' and
     `max_heap_table_size'.) If an in-memory temporary table exceeds
     the limit, MySQL automatically converts it to an on-disk `MyISAM'
     table. Increase the value of `tmp_table_size' (and
     `max_heap_table_size' if necessary) if you do many advanced `GROUP
     BY' queries and you have lots of memory. This variable does not
     apply to user-created `MEMORY' tables.

     You can compare the number of internal on-disk temporary tables
     created to the total number of internal temporary tables created
     by comparing the values of the `Created_tmp_disk_tables' and
     `Created_tmp_tables' variables.

     See also *Note internal-temporary-tables::.

   *  `tmpdir'

     Options for tmpdir      *Command-Line        `--tmpdir=path'        
     Format*                              
     **                   `-t'            
     *Option-File Format* `tmpdir'        
     *Option Sets         Yes,            
     Variable*            `tmpdir'        
     *Variable Name*      `tmpdir'        
     *Variable Scope*     Global          
     *Dynamic Variable*   No              
                          *Permitted        
                          Values          
                          *               
     *Type*               `file           
                          name'           


     The directory used for temporary files and temporary tables.  This
     variable can be set to a list of several paths that are used in
     round-robin fashion. Paths should be separated by colon characters
     (``:'') on Unix and semicolon characters (``;'') on Windows,
     NetWare, and OS/2.

     The multiple-directory feature can be used to spread the load
     between several physical disks. If the MySQL server is acting as a
     replication slave, you should not set `tmpdir' to point to a
     directory on a memory-based file system or to a directory that is
     cleared when the server host restarts. A replication slave needs
     some of its temporary files to survive a machine restart so that
     it can replicate temporary tables or *Note `LOAD DATA INFILE':
     load-data. operations. If files in the temporary file directory
     are lost when the server restarts, replication fails. You can set
     the slave's temporary directory using the `slave_load_tmpdir'
     variable.  In that case, the slave will not use the general
     `tmpdir' value and you can set `tmpdir' to a nonpermanent location.

   *  `transaction_alloc_block_size'

     Options for transaction_alloc_block_size      *Command-Line        `--transaction_alloc_block_size=#'        
     Format*                              
     *Option-File Format* `transaction_alloc_block_size'        
     *Option Sets         Yes,            
     Variable*            `transaction_alloc_block_size'        
     *Variable Name*      `transaction_alloc_block_size'        
     *Variable Scope*     Global,         
                          Session         
     *Dynamic Variable*   Yes             
                          *Permitted        
                          Values          
                          *               
     *Platform Bit Size*  `32'            
     *Type*               `numeric'        
     *Default*            `8192'          
     *Range*              `1024           
                          ..              
                          4294967295'        
     *Block Size*         `1024'          
                          *Permitted        
                          Values          
                          *               
     *Platform Bit Size*  `64'            
     *Type*               `numeric'        
     *Default*            `8192'          
     *Range*              `1024           
                          ..              
                          18446744073709547520'        
     *Block Size*         `1024'          


     The amount in bytes by which to increase a per-transaction memory
     pool which needs memory. See the description of
     `transaction_prealloc_size'.

   *  `transaction_prealloc_size'

     Options for transaction_prealloc_size      *Command-Line        `--transaction_prealloc_size=#'        
     Format*                              
     *Option-File Format* `transaction_prealloc_size'        
     *Option Sets         Yes,            
     Variable*            `transaction_prealloc_size'        
     *Variable Name*      `transaction_prealloc_size'        
     *Variable Scope*     Global,         
                          Session         
     *Dynamic Variable*   Yes             
                          *Permitted        
                          Values          
                          *               
     *Platform Bit Size*  `32'            
     *Type*               `numeric'        
     *Default*            `4096'          
     *Range*              `1024           
                          ..              
                          4294967295'        
     *Block Size*         `1024'          
                          *Permitted        
                          Values          
                          *               
     *Platform Bit Size*  `64'            
     *Type*               `numeric'        
     *Default*            `4096'          
     *Range*              `1024           
                          ..              
                          18446744073709547520'        
     *Block Size*         `1024'          


     There is a per-transaction memory pool from which various
     transaction-related allocations take memory. The initial size of
     the pool in bytes is `transaction_prealloc_size'.  For every
     allocation that cannot be satisfied from the pool because it has
     insufficient memory available, the pool is increased by
     `transaction_alloc_block_size' bytes. When the transaction ends,
     the pool is truncated to `transaction_prealloc_size' bytes.

     By making `transaction_prealloc_size' sufficiently large to
     contain all statements within a single transaction, you can avoid
     many `malloc()' calls.

   *  `tx_isolation'

     Options for tx_isolation      *Variable Name*      `tx_isolation'        
     *Variable Scope*     Global,         
                          Session         
     *Dynamic Variable*   Yes             
                          *Permitted        
                          Values          
                          *               
     *Type*               `enumeration'        
     *Default*            `REPEATABLE-READ'        
     *Valid Values*       `READ-UNCOMMITTED'        
                          `READ-COMMITTED'        
                          `REPEATABLE-READ'        
                          `               
                          SERIALIZABLE        
                          '               


     The default transaction isolation level. Defaults to
     `REPEATABLE-READ'.

     This variable is set by the *Note `SET TRANSACTION ISOLATION
     LEVEL': set-transaction. statement. See *Note set-transaction::.
     If you set `tx_isolation' directly to an isolation level name that
     contains a space, the name should be enclosed within quotation
     marks, with the space replaced by a dash. For example:

          SET tx_isolation = 'READ-COMMITTED';

     Any unique prefix of a valid value may be used to set the value of
     this variable.

     The default transactional isolation level can also be set at
     startup using the `--transaction-isolation' server option.

   *  `unique_checks'

     Options for unique_checks      *Variable Name*      `unique_checks'        
     *Variable Scope*     Session         
     *Dynamic Variable*   Yes             
                          *Permitted        
                          Values          
                          *               
     *Type*               `boolean'        
     *Default*            `1'             


     If set to 1 (the default), uniqueness checks for secondary indexes
     in `InnoDB' tables are performed. If set to 0, storage engines are
     permitted to assume that duplicate keys are not present in input
     data. If you know for certain that your data does not contain
     uniqueness violations, you can set this to 0 to speed up large
     table imports to `InnoDB'.

     Note that setting this variable to 0 does not _require_ storage
     engines to ignore duplicate keys. An engine is still permitted to
     check for them and issue duplicate-key errors if it detects them.

   *  `updatable_views_with_limit'

     Options for updatable_views_with_limit      *Version Introduced* 5.0.2           
     *Command-Line        `--updatable_views_with_limit=#'        
     Format*                              
     *Option-File Format* `updatable_views_with_limit'        
     *Option Sets         Yes,            
     Variable*            `updatable_views_with_limit'        
     *Variable Name*      `updatable_views_with_limit'        
     *Variable Scope*     Global,         
                          Session         
     *Dynamic Variable*   Yes             
                          *Permitted        
                          Values          
                          *               
     *Type*               `boolean'        
     *Default*            `1'             


     This variable controls whether updates to a view can be made when
     the view does not contain all columns of the primary key defined
     in the underlying table, if the update statement contains a
     `LIMIT' clause. (Such updates often are generated by GUI tools.)
     An update is an *Note `UPDATE': update. or *Note `DELETE': delete.
     statement. Primary key here means a `PRIMARY KEY', or a `UNIQUE'
     index in which no column can contain `NULL'.

     The variable can have two values:

        * `1' or `YES': Issue a warning only (not an error message).
          This is the default value.

        * `0' or `NO': Prohibit the update.

     This variable was added in MySQL 5.0.2.

   *  `version'

     Options for version      *Variable Name*      `version'        
     *Variable Scope*     Global          
     *Dynamic Variable*   No              


     The version number for the server. The value might also include a
     suffix indicating server build or configuration information.
     `-log' indicates that one or more of the general log, slow query
     log, or binary log are enabled. `-debug' indicates that the server
     was built with debugging support enabled.

     Options for version      *Variable Name*      `version'        
     *Variable Scope*     Global          
     *Dynamic Variable*   No              


     Starting with MySQL 5.0.24, the version number will also indicate
     whether the server is a standard release (Community) or Enterprise
     release (for example, ` 5.0.28-enterprise-gpl-nt').

   *  `version_bdb'

     The `BDB' storage engine version.

   *  `version_comment'

     Options for version_comment      *Variable Name*      `version_comment'        
     *Variable Scope*     Global          
     *Dynamic Variable*   No              
                          *Permitted        
                          Values          
                          *               
     *Type*               `string'        


     The `configure' script has a `--with-comment' option that permits
     a comment to be specified when building MySQL. This variable
     contains the value of that comment.

     For precompiled binaries, this variable will hold the server
     version and license information. Starting with MySQL 5.0.24,
     `version_comment' will include the full server type and license.
     For community users this will appear as `MySQL Community Edition -
     Standard (GPL)'. For Enterprise users, the version might be
     displayed as `MySQL Enterprise Server (GPL)'.  The corresponding
     license for your MySQL binary is shown in parentheses. For server
     compiled from source, the default value will be the same as that
     for Community releases.

   *  `version_compile_machine'

     Options for version_compile_machine      *Variable Name*      `version_compile_machine'        
     *Variable Scope*     Global          
     *Dynamic Variable*   No              
                          *Permitted        
                          Values          
                          *               
     *Type*               `string'        


     The type of machine or architecture on which MySQL was built.

   *  `version_compile_os'

     Options for version_compile_os      *Variable Name*      `version_compile_os'        
     *Variable Scope*     Global          
     *Dynamic Variable*   No              
                          *Permitted        
                          Values          
                          *               
     *Type*               `string'        


     The type of operating system on which MySQL was built.

   *  `wait_timeout'

     Options for wait_timeout      *Command-Line        `--wait_timeout=#'        
     Format*                              
     *Option-File Format* `wait_timeout'        
     *Option Sets         Yes,            
     Variable*            `wait_timeout'        
     *Variable Name*      `wait_timeout'        
     *Variable Scope*     Global,         
                          Session         
     *Dynamic Variable*   Yes             
                          *Permitted        
                          Values          
                          *               
     *Type*               `numeric'        
     *Default*            `28800'         
     *Range*              `1 ..           
                          31536000'        
                          *Permitted        
                          Values          
                          *               
     *Type* (windows)     `numeric'        
     *Default*            `28800'         
     *Range*              `1 ..           
                          2147483'        


     The number of seconds the server waits for activity on a
     noninteractive connection before closing it. This timeout applies
     only to TCP/IP and Unix socket file connections, not to
     connections made using named pipes, or shared memory.

     On thread startup, the session `wait_timeout' value is initialized
     from the global `wait_timeout' value or from the global
     `interactive_timeout' value, depending on the type of client (as
     defined by the `CLIENT_INTERACTIVE' connect option to *Note
     `mysql_real_connect()': mysql-real-connect.). See also
     `interactive_timeout'.

   *  `warning_count'

     The number of errors, warnings, and notes that resulted from the
     last statement that generated messages. This variable is read
     only. See *Note show-warnings::.


File: manual.info,  Node: using-system-variables,  Next: server-status-variables,  Prev: server-system-variables,  Up: mysqld-server

6.1.4 Using System Variables
----------------------------

* Menu:

* structured-system-variables::  Structured System Variables
* dynamic-system-variables::     Dynamic System Variables

The MySQL server maintains many system variables that indicate how it
is configured. *Note server-system-variables::, describes the meaning
of these variables. Each system variable has a default value. System
variables can be set at server startup using options on the command
line or in an option file. Most of them can be changed dynamically
while the server is running by means of the *Note `SET': set-option.
statement, which enables you to modify operation of the server without
having to stop and restart it. You can refer to system variable values
in expressions.

The server maintains two kinds of system variables. Global variables
affect the overall operation of the server. Session variables affect
its operation for individual client connections.  A given system
variable can have both a global and a session value. Global and session
system variables are related as follows:

   * When the server starts, it initializes all global variables to
     their default values. These defaults can be changed by options
     specified on the command line or in an option file. (See *Note
     program-options::.)

   * The server also maintains a set of session variables for each
     client that connects. The client's session variables are
     initialized at connect time using the current values of the
     corresponding global variables. For example, the client's SQL mode
     is controlled by the session `sql_mode' value, which is
     initialized when the client connects to the value of the global
     `sql_mode' value.

System variable values can be set globally at server startup by using
options on the command line or in an option file. When you use a
startup option to set a variable that takes a numeric value, the value
can be given with a suffix of `K', `M', or `G' (either uppercase or
lowercase) to indicate a multiplier of 1024, 1024^2 or 1024^3; that is,
units of kilobytes, megabytes, or gigabytes, respectively. Thus, the
following command starts the server with a query cache size of 16
megabytes and a maximum packet size of one gigabyte:

     mysqld --query_cache_size=16M --max_allowed_packet=1G

Within an option file, those variables are set like this:

     [mysqld]
     query_cache_size=16M
     max_allowed_packet=1G

The lettercase of suffix letters does not matter; `16M' and `16m' are
equivalent, as are `1G' and `1g'.

If you want to restrict the maximum value to which a system variable
can be set at runtime with the *Note `SET': set-option.  statement, you
can specify this maximum by using an option of the form
`--maximum-VAR_NAME=VALUE' at server startup. For example, to prevent
the value of `query_cache_size' from being increased to more than 32MB
at runtime, use the option `--maximum-query_cache_size=32M'.

Many system variables are dynamic and can be changed while the server
runs by using the *Note `SET': set-option.  statement. For a list, see
*Note dynamic-system-variables::. To change a system variable with
*Note `SET': set-option, refer to it as VAR_NAME, optionally preceded
by a modifier:

   * To indicate explicitly that a variable is a global variable,
     precede its name by `GLOBAL' or `@@global.'. The `SUPER' privilege
     is required to set global variables.

   * To indicate explicitly that a variable is a session variable,
     precede its name by `SESSION', `@@session.', or `@@'.  Setting a
     session variable requires no special privilege, but a client can
     change only its own session variables, not those of any other
     client.

   * `LOCAL' and `@@local.' are synonyms for `SESSION' and `@@session.'.

   * If no modifier is present, *Note `SET': set-option.  changes the
     session variable.

A *Note `SET': set-option.  statement can contain multiple variable
assignments, separated by commas. If you set several system variables,
the most recent `GLOBAL' or `SESSION' modifier in the statement is used
for following variables that have no modifier specified.

Examples:

     SET sort_buffer_size=10000;
     SET @@local.sort_buffer_size=10000;
     SET GLOBAL sort_buffer_size=1000000, SESSION sort_buffer_size=1000000;
     SET @@sort_buffer_size=1000000;
     SET @@global.sort_buffer_size=1000000, @@local.sort_buffer_size=1000000;

The `@@VAR_NAME' syntax for system variables is supported for
compatibility with some other database systems.

If you change a session system variable, the value remains in effect
until your session ends or until you change the variable to a different
value. The change is not visible to other clients.

If you change a global system variable, the value is remembered and
used for new connections until the server restarts. (To make a global
system variable setting permanent, you should set it in an option
file.) The change is visible to any client that accesses that global
variable. However, the change affects the corresponding session
variable only for clients that connect after the change. The global
variable change does not affect the session variable for any client
that is currently connected (not even that of the client that issues the
*Note `SET GLOBAL': set-option.  statement).

To prevent incorrect usage, MySQL produces an error if you use *Note
`SET GLOBAL': set-option.  with a variable that can only be used with
*Note `SET SESSION': set-option.  or if you do not specify `GLOBAL' (or
`@@global.') when setting a global variable.

To set a `SESSION' variable to the `GLOBAL' value or a `GLOBAL' value
to the compiled-in MySQL default value, use the `DEFAULT' keyword. For
example, the following two statements are identical in setting the
session value of `max_join_size' to the global value:

     SET max_join_size=DEFAULT;
     SET @@session.max_join_size=@@global.max_join_size;

Not all system variables can be set to `DEFAULT'.  In such cases, use
of `DEFAULT' results in an error.

You can refer to the values of specific global or session system
variables in expressions by using one of the `@@'-modifiers. For
example, you can retrieve values in a *Note `SELECT': select. statement
like this:

     SELECT @@global.sql_mode, @@session.sql_mode, @@sql_mode;

When you refer to a system variable in an expression as `@@VAR_NAME'
(that is, when you do not specify `@@global.' or `@@session.'), MySQL
returns the session value if it exists and the global value otherwise.
(This differs from `SET @@VAR_NAME = VALUE', which always refers to the
session value.)

*Note*:

Some variables displayed by `SHOW VARIABLES' may not be available using
`SELECT @@VAR_NAME' syntax; an `Unknown system variable' occurs. As a
workaround in such cases, you can use `SHOW VARIABLES LIKE 'VAR_NAME''.

Suffixes for specifying a value multiplier can be used when setting a
variable at server startup, but not to set the value with *Note `SET':
set-option. at runtime. On the other hand, with *Note `SET':
set-option. you can assign a variable's value using an expression,
which is not true when you set a variable at server startup. For
example, the first of the following lines is legal at server startup,
but the second is not:

     shell> mysql --max_allowed_packet=16M
     shell> mysql --max_allowed_packet=16*1024*1024

Conversely, the second of the following lines is legal at runtime, but
the first is not:

     mysql> SET GLOBAL max_allowed_packet=16M;
     mysql> SET GLOBAL max_allowed_packet=16*1024*1024;

*Note*:

Some system variables can be enabled with the *Note `SET': set-option.
statement by setting them to `ON' or `1', or disabled by setting them to
`OFF' or `0'. However, to set such a variable on the command line or in
an option file, you must set it to `1' or `0'; setting it to `ON' or
`OFF' will not work. For example, on the command line,
`--delay_key_write=1' works but `--delay_key_write=ON' does not.

To display system variable names and values, use the *Note `SHOW
VARIABLES': show-variables. statement:

     mysql> SHOW VARIABLES;
     +--------+--------------------------------------------------------------+
     | Variable_name                   | Value                               |
     +--------+--------------------------------------------------------------+
     | auto_increment_increment        | 1                                   |
     | auto_increment_offset           | 1                                   |
     | automatic_sp_privileges         | ON                                  |
     | back_log                        | 50                                  |
     | basedir                         | /                                   |
     | bdb_cache_size                  | 8388600                             |
     | bdb_home                        | /var/lib/mysql/                     |
     | bdb_log_buffer_size             | 32768                               |
     | bdb_logdir                      |                                     |
     | bdb_max_lock                    | 10000                               |
     | bdb_shared_data                 | OFF                                 |
     | bdb_tmpdir                      | /tmp/                               |
     | binlog_cache_size               | 32768                               |
     | bulk_insert_buffer_size         | 8388608                             |
     | character_set_client            | latin1                              |
     | character_set_connection        | latin1                              |
     | character_set_database          | latin1                              |
     | character_set_results           | latin1                              |
     | character_set_server            | latin1                              |
     | character_set_system            | utf8                                |
     | character_sets_dir              | /usr/share/mysql/charsets/          |
     | collation_connection            | latin1_swedish_ci                   |
     | collation_database              | latin1_swedish_ci                   |
     | collation_server                | latin1_swedish_ci                   |
     ...
     | innodb_additional_mem_pool_size | 1048576                             |
     | innodb_autoextend_increment     | 8                                   |
     | innodb_buffer_pool_awe_mem_mb   | 0                                   |
     | innodb_buffer_pool_size         | 8388608                             |
     | innodb_checksums                | ON                                  |
     | innodb_commit_concurrency       | 0                                   |
     | innodb_concurrency_tickets      | 500                                 |
     | innodb_data_file_path           | ibdata1:10M:autoextend              |
     | innodb_data_home_dir            |                                     |
     ...
     | version                         | 5.0.19                              |
     | version_comment                 | MySQL Community Edition - (GPL)     |
     | version_compile_machine         | i686                                |
     | version_compile_os              | pc-linux-gnu                        |
     | wait_timeout                    | 28800                               |
     +--------+--------------------------------------------------------------+

With a `LIKE' clause, the statement displays only those variables that
match the pattern. To obtain a specific variable name, use a `LIKE'
clause as shown:

     SHOW VARIABLES LIKE 'max_join_size';
     SHOW SESSION VARIABLES LIKE 'max_join_size';

To get a list of variables whose name match a pattern, use the ``%''
wildcard character in a `LIKE' clause:

     SHOW VARIABLES LIKE '%size%';
     SHOW GLOBAL VARIABLES LIKE '%size%';

Wildcard characters can be used in any position within the pattern to
be matched. Strictly speaking, because ``_'' is a wildcard that matches
any single character, you should escape it as ``\_'' to match it
literally. In practice, this is rarely necessary.

For *Note `SHOW VARIABLES': show-variables, if you specify neither
`GLOBAL' nor `SESSION', MySQL returns `SESSION' values.

The reason for requiring the `GLOBAL' keyword when setting
`GLOBAL'-only variables but not when retrieving them is to prevent
problems in the future. If we were to remove a `SESSION' variable that
has the same name as a `GLOBAL' variable, a client with the `SUPER'
privilege might accidentally change the `GLOBAL' variable rather than
just the `SESSION' variable for its own connection. If we add a
`SESSION' variable with the same name as a `GLOBAL' variable, a client
that intends to change the `GLOBAL' variable might find only its own
`SESSION' variable changed.


File: manual.info,  Node: structured-system-variables,  Next: dynamic-system-variables,  Prev: using-system-variables,  Up: using-system-variables

6.1.4.1 Structured System Variables
...................................

A structured variable differs from a regular system variable in two
respects:

   * Its value is a structure with components that specify server
     parameters considered to be closely related.

   * There might be several instances of a given type of structured
     variable. Each one has a different name and refers to a different
     resource maintained by the server.

MySQL 5.0 supports one structured variable type, which specifies
parameters governing the operation of key caches. A key cache
structured variable has these components:

   * `key_buffer_size'

   * `key_cache_block_size'

   * `key_cache_division_limit'

   * `key_cache_age_threshold'

This section describes the syntax for referring to structured
variables. Key cache variables are used for syntax examples, but
specific details about how key caches operate are found elsewhere, in
*Note myisam-key-cache::.

To refer to a component of a structured variable instance, you can use
a compound name in INSTANCE_NAME.COMPONENT_NAME format.  Examples:

     hot_cache.key_buffer_size
     hot_cache.key_cache_block_size
     cold_cache.key_cache_block_size

For each structured system variable, an instance with the name of
`default' is always predefined. If you refer to a component of a
structured variable without any instance name, the `default' instance
is used. Thus, `default.key_buffer_size' and `key_buffer_size' both
refer to the same system variable.

Structured variable instances and components follow these naming rules:

   * For a given type of structured variable, each instance must have a
     name that is unique _within_ variables of that type. However,
     instance names need not be unique _across_ structured variable
     types. For example, each structured variable has an instance named
     `default', so `default' is not unique across variable types.

   * The names of the components of each structured variable type must
     be unique across all system variable names. If this were not true
     (that is, if two different types of structured variables could
     share component member names), it would not be clear which default
     structured variable to use for references to member names that are
     not qualified by an instance name.

   * If a structured variable instance name is not legal as an unquoted
     identifier, refer to it as a quoted identifier using backticks.
     For example, `hot-cache' is not legal, but ``hot-cache`' is.

   * `global', `session', and `local' are not legal instance names. This
     avoids a conflict with notation such as `@@global.VAR_NAME' for
     referring to nonstructured system variables.

Currently, the first two rules have no possibility of being violated
because the only structured variable type is the one for key caches.
These rules will assume greater significance if some other type of
structured variable is created in the future.

With one exception, you can refer to structured variable components
using compound names in any context where simple variable names can
occur. For example, you can assign a value to a structured variable
using a command-line option:

     shell> mysqld --hot_cache.key_buffer_size=64K

In an option file, use this syntax:

     [mysqld]
     hot_cache.key_buffer_size=64K

If you start the server with this option, it creates a key cache named
`hot_cache' with a size of 64KB in addition to the default key cache
that has a default size of 8MB.

Suppose that you start the server as follows:

     shell> mysqld --key_buffer_size=256K \
              --extra_cache.key_buffer_size=128K \
              --extra_cache.key_cache_block_size=2048

In this case, the server sets the size of the default key cache to
256KB. (You could also have written `--default.key_buffer_size=256K'.)
In addition, the server creates a second key cache named `extra_cache'
that has a size of 128KB, with the size of block buffers for caching
table index blocks set to 2048 bytes.

The following example starts the server with three different key caches
having sizes in a 3:1:1 ratio:

     shell> mysqld --key_buffer_size=6M \
              --hot_cache.key_buffer_size=2M \
              --cold_cache.key_buffer_size=2M

Structured variable values may be set and retrieved at runtime as well.
For example, to set a key cache named `hot_cache' to a size of 10MB,
use either of these statements:

     mysql> SET GLOBAL hot_cache.key_buffer_size = 10*1024*1024;
     mysql> SET @@global.hot_cache.key_buffer_size = 10*1024*1024;

To retrieve the cache size, do this:

     mysql> SELECT @@global.hot_cache.key_buffer_size;

However, the following statement does not work. The variable is not
interpreted as a compound name, but as a simple string for a `LIKE'
pattern-matching operation:

     mysql> SHOW GLOBAL VARIABLES LIKE 'hot_cache.key_buffer_size';

This is the exception to being able to use structured variable names
anywhere a simple variable name may occur.


File: manual.info,  Node: dynamic-system-variables,  Prev: structured-system-variables,  Up: using-system-variables

6.1.4.2 Dynamic System Variables
................................

Many server system variables are dynamic and can be set at runtime
using *Note `SET GLOBAL': set-option. or *Note `SET SESSION':
set-option. You can also obtain their values using *Note `SELECT':
select. See *Note using-system-variables::.

The following table shows the full list of all dynamic system
variables. The last column indicates for each variable whether `GLOBAL'
or `SESSION' (or both) apply. The table also lists session options that
can be set with the *Note `SET': set-option.  statement. *Note
server-system-variables::, discusses these options.

Variables that have a type of `string' take a string value. Variables
that have a type of `numeric' take a numeric value. Variables that have
a type of `boolean' can be set to 0, 1, `ON' or `OFF'. (If you set them
on the command line or in an option file, use the numeric values.)
Variables that are marked as `enumeration' normally should be set to
one of the available values for the variable, but can also be set to
the number that corresponds to the desired enumeration value. For
enumerated system variables, the first enumeration value corresponds to
0. This differs from *Note `ENUM': enum. columns, for which the first
enumeration value corresponds to 1.

*Dynamic Variable Summary*

Variable Name                 Variable Type  Variable Scope
`auto_increment_increment'    numeric        `GLOBAL' |
                                             `SESSION'
`auto_increment_offset'       numeric        `GLOBAL' |
                                             `SESSION'
`autocommit'                  boolean        `SESSION'
`automatic_sp_privileges'     boolean        `GLOBAL'
`big_tables'                  boolean        `SESSION'
`binlog_cache_size'           numeric        `GLOBAL'
`bulk_insert_buffer_size'     numeric        `GLOBAL' |
                                             `SESSION'
`character_set_client'        string         `GLOBAL' |
                                             `SESSION'
`character_set_connection'    string         `GLOBAL' |
                                             `SESSION'
`character_set_database'      string         `GLOBAL' |
                                             `SESSION'
`character_set_filesystem'    string         `GLOBAL' |
                                             `SESSION'
`character_set_results'       string         `GLOBAL' |
                                             `SESSION'
`character_set_server'        string         `GLOBAL' |
                                             `SESSION'
`collation_connection'        string         `GLOBAL' |
                                             `SESSION'
`collation_database'          string         `GLOBAL' |
                                             `SESSION'
`collation_server'            string         `GLOBAL' |
                                             `SESSION'
`completion_type'             numeric        `GLOBAL' |
                                             `SESSION'
`concurrent_insert'           boolean        `GLOBAL'
`connect_timeout'             numeric        `GLOBAL'
`debug'                       string         `GLOBAL' |
                                             `SESSION'
`storage_engine'              enumeration    `GLOBAL' |
                                             `SESSION'
`default_week_format'         numeric        `GLOBAL' |
                                             `SESSION'
`delay_key_write'             enumeration    `GLOBAL'
`delayed_insert_limit'        numeric        `GLOBAL'
`delayed_insert_timeout'      numeric        `GLOBAL'
`delayed_queue_size'          numeric        `GLOBAL'
`div_precision_increment'     numeric        `GLOBAL' |
                                             `SESSION'
`engine_condition_pushdown'   boolean        `GLOBAL' |
                                             `SESSION'
`expire_logs_days'            numeric        `GLOBAL'
`flush'                       boolean        `GLOBAL'
`flush_time'                  numeric        `GLOBAL'
`foreign_key_checks'          boolean        `SESSION'
`ft_boolean_syntax'           string         `GLOBAL'
`group_concat_max_len'        numeric        `GLOBAL' |
                                             `SESSION'
`identity'                    numeric        `SESSION'
`init_connect'                string         `GLOBAL'
`init_slave'                  string         `GLOBAL'
`innodb_autoextend_increment' numeric        `GLOBAL'
`innodb_commit_concurrency'   numeric        `GLOBAL'
`innodb_concurrency_tickets'  numeric        `GLOBAL'
`innodb_fast_shutdown'        numeric        `GLOBAL'
`innodb_flush_log_at_trx_commit'enumeration    `GLOBAL'
`innodb_max_dirty_pages_pct'  numeric        `GLOBAL'
`innodb_max_purge_lag'        numeric        `GLOBAL'
`innodb_support_xa'           boolean        `GLOBAL' |
                                             `SESSION'
`innodb_sync_spin_loops'      numeric        `GLOBAL'
`innodb_table_locks'          boolean        `GLOBAL' |
                                             `SESSION'
`innodb_thread_concurrency'   numeric        `GLOBAL'
`innodb_thread_sleep_delay'   numeric        `GLOBAL'
`innodb_use_legacy_cardinality_algorithm'boolean        `GLOBAL'
`insert_id'                   numeric        `SESSION'
`interactive_timeout'         numeric        `GLOBAL' |
                                             `SESSION'
`join_buffer_size'            numeric        `GLOBAL' |
                                             `SESSION'
`keep_files_on_create'        boolean        `GLOBAL' |
                                             `SESSION'
`key_buffer_size'             numeric        `GLOBAL'
`key_cache_age_threshold'     numeric        `GLOBAL'
`key_cache_block_size'        numeric        `GLOBAL'
`key_cache_division_limit'    numeric        `GLOBAL'
`last_insert_id'              numeric        `SESSION'
`lc_time_names'               string         `GLOBAL' |
                                             `SESSION'
`local_infile'                boolean        `GLOBAL'
`log_bin_trust_function_creators'boolean        `GLOBAL'
`log_bin_trust_routine_creators'boolean        `GLOBAL'
`log_queries_not_using_indexes'boolean        `GLOBAL'
`log_warnings'                numeric        `GLOBAL' |
                                             `SESSION'
`long_query_time'             numeric        `GLOBAL' |
                                             `SESSION'
`low_priority_updates'        boolean        `GLOBAL' |
                                             `SESSION'
`max_allowed_packet'          numeric        `GLOBAL'
`max_binlog_cache_size'       numeric        `GLOBAL'
`max_binlog_size'             numeric        `GLOBAL'
`max_connect_errors'          numeric        `GLOBAL'
`max_connections'             numeric        `GLOBAL'
`max_delayed_threads'         numeric        `GLOBAL' |
                                             `SESSION'
`max_error_count'             numeric        `GLOBAL' |
                                             `SESSION'
`max_heap_table_size'         numeric        `GLOBAL' |
                                             `SESSION'
`max_insert_delayed_threads'  numeric        `GLOBAL' |
                                             `SESSION'
`max_join_size'               numeric        `GLOBAL' |
                                             `SESSION'
`max_length_for_sort_data'    numeric        `GLOBAL' |
                                             `SESSION'
`max_prepared_stmt_count'     numeric        `GLOBAL'
`max_relay_log_size'          numeric        `GLOBAL'
`max_seeks_for_key'           numeric        `GLOBAL' |
                                             `SESSION'
`max_sort_length'             numeric        `GLOBAL' |
                                             `SESSION'
`max_sp_recursion_depth'      numeric        `GLOBAL' |
                                             `SESSION'
`max_tmp_tables'              numeric        `GLOBAL' |
                                             `SESSION'
`max_user_connections'        numeric        `GLOBAL' |
                                             `SESSION'
`max_write_lock_count'        numeric        `GLOBAL'
`multi_range_count'           numeric        `GLOBAL' |
                                             `SESSION'
`myisam_data_pointer_size'    numeric        `GLOBAL'
`myisam_max_sort_file_size'   numeric        `GLOBAL'
`myisam_repair_threads'       numeric        `GLOBAL' |
                                             `SESSION'
`myisam_sort_buffer_size'     numeric        `GLOBAL' |
                                             `SESSION'
`myisam_stats_method'         enumeration    `GLOBAL' |
                                             `SESSION'
`ndb_autoincrement_prefetch_sz'numeric        `GLOBAL' |
                                             `SESSION'
`ndb_cache_check_time'        numeric        `GLOBAL'
`ndb_force_send'              boolean        `GLOBAL' |
                                             `SESSION'
`ndb_use_exact_count'         boolean        `GLOBAL' |
                                             `SESSION'
`ndb_use_transactions'        boolean        `GLOBAL' |
                                             `SESSION'
`net_buffer_length'           numeric        `GLOBAL' |
                                             `SESSION'
`net_read_timeout'            numeric        `GLOBAL' |
                                             `SESSION'
`net_retry_count'             numeric        `GLOBAL' |
                                             `SESSION'
`net_write_timeout'           numeric        `GLOBAL' |
                                             `SESSION'
`new'                         boolean        `GLOBAL' |
                                             `SESSION'
`old_passwords'               boolean        `GLOBAL' |
                                             `SESSION'
`optimizer_prune_level'       boolean        `GLOBAL' |
                                             `SESSION'
`optimizer_search_depth'      numeric        `GLOBAL' |
                                             `SESSION'
`preload_buffer_size'         numeric        `GLOBAL' |
                                             `SESSION'
`profiling'                   boolean        `SESSION'
`profiling_history_size'      numeric        `GLOBAL' |
                                             `SESSION'
`pseudo_thread_id'            numeric        `SESSION'
`query_alloc_block_size'      numeric        `GLOBAL' |
                                             `SESSION'
`query_cache_limit'           numeric        `GLOBAL'
`query_cache_min_res_unit'    numeric        `GLOBAL'
`query_cache_size'            numeric        `GLOBAL'
`query_cache_type'            enumeration    `GLOBAL' |
                                             `SESSION'
`query_cache_wlock_invalidate'boolean        `GLOBAL' |
                                             `SESSION'
`query_prealloc_size'         numeric        `GLOBAL' |
                                             `SESSION'
`rand_seed1'                  numeric        `SESSION'
`rand_seed2'                  numeric        `SESSION'
`range_alloc_block_size'      numeric        `GLOBAL' |
                                             `SESSION'
`read_buffer_size'            numeric        `GLOBAL' |
                                             `SESSION'
`read_only'                   numeric        `GLOBAL'
`read_rnd_buffer_size'        numeric        `GLOBAL' |
                                             `SESSION'
`relay_log_purge'             boolean        `GLOBAL'
`rpl_recovery_rank'           numeric        `GLOBAL'
`safe_show_database'          boolean        `GLOBAL'
`secure_auth'                 boolean        `GLOBAL'
`server_id'                   numeric        `GLOBAL'
`slave_compressed_protocol'   boolean        `GLOBAL'
`slave_net_timeout'           numeric        `GLOBAL'
`slave_transaction_retries'   numeric        `GLOBAL'
`slow_launch_time'            numeric        `GLOBAL'
`sort_buffer_size'            numeric        `GLOBAL' |
                                             `SESSION'
`sql_auto_is_null'            boolean        `SESSION'
`sql_big_selects'             boolean        `SESSION'
`sql_big_tables'              boolean        `SESSION'
`sql_buffer_result'           boolean        `SESSION'
`sql_log_bin'                 boolean        `SESSION'
`sql_log_off'                 boolean        `SESSION'
`sql_log_update'              boolean        `SESSION'
`sql_low_priority_updates'    boolean        `GLOBAL' |
                                             `SESSION'
`sql_max_join_size'           numeric        `GLOBAL' |
                                             `SESSION'
`sql_mode'                    set            `GLOBAL' |
                                             `SESSION'
`sql_notes'                   boolean        `SESSION'
`sql_quote_show_create'       boolean        `SESSION'
`sql_safe_updates'            boolean        `SESSION'
`sql_select_limit'            numeric        `GLOBAL' |
                                             `SESSION'
`sql_slave_skip_counter'      numeric        `GLOBAL'
`sql_warnings'                boolean        `SESSION'
`storage_engine'              enumeration    `GLOBAL' |
                                             `SESSION'
`sync_binlog'                 numeric        `GLOBAL'
`sync_frm'                    boolean        `GLOBAL'
`table_cache'                 numeric        `GLOBAL'
`table_lock_wait_timeout'     numeric        `GLOBAL'
`table_type'                  enumeration    `GLOBAL' |
                                             `SESSION'
`thread_cache_size'           numeric        `GLOBAL'
`time_zone'                   string         `GLOBAL' |
                                             `SESSION'
`timed_mutexes'               boolean        `GLOBAL'
`timestamp'                   numeric        `SESSION'
`tmp_table_size'              numeric        `GLOBAL' |
                                             `SESSION'
`transaction_alloc_block_size'numeric        `GLOBAL' |
                                             `SESSION'
`transaction_prealloc_size'   numeric        `GLOBAL' |
                                             `SESSION'
`tx_isolation'                enumeration    `GLOBAL' |
                                             `SESSION'
`unique_checks'               boolean        `SESSION'
`updatable_views_with_limit'  boolean        `GLOBAL' |
                                             `SESSION'
`wait_timeout'                numeric        `GLOBAL' |
                                             `SESSION'


File: manual.info,  Node: server-status-variables,  Next: server-sql-mode,  Prev: using-system-variables,  Up: mysqld-server

6.1.5 Server Status Variables
-----------------------------

The server maintains many status variables that provide information
about its operation. You can view these variables and their values by
using the `SHOW [GLOBAL | SESSION] STATUS' statement (see *Note
show-status::).  The optional `GLOBAL' keyword aggregates the values
over all connections, and `SESSION' shows the values for the current
connection.

     mysql> SHOW GLOBAL STATUS;
     +-----------------------------------+------------+
     | Variable_name                     | Value      |
     +-----------------------------------+------------+
     | Aborted_clients                   | 0          |
     | Aborted_connects                  | 0          |
     | Bytes_received                    | 155372598  |
     | Bytes_sent                        | 1176560426 |
     ...
     | Connections                       | 30023      |
     | Created_tmp_disk_tables           | 0          |
     | Created_tmp_files                 | 3          |
     | Created_tmp_tables                | 2          |
     ...
     | Threads_created                   | 217        |
     | Threads_running                   | 88         |
     | Uptime                            | 1389872    |
     +-----------------------------------+------------+

The following table lists all available server status variables:

*Status Variable Summary*

Variable Name                 Variable Type  Variable Scope
`Aborted_clients'             numeric        `GLOBAL'
`Aborted_connects'            numeric        `GLOBAL'
`Binlog_cache_disk_use'       numeric        `GLOBAL'
`Binlog_cache_use'            numeric        `GLOBAL'
`Bytes_received'              numeric        `GLOBAL' |
                                             `SESSION'
`Bytes_sent'                  numeric        `GLOBAL' |
                                             `SESSION'
`Com_admin_commands'          numeric        `GLOBAL' |
                                             `SESSION'
`Com_alter_db'                numeric        `GLOBAL' |
                                             `SESSION'
`Com_alter_event'             numeric        `GLOBAL' |
                                             `SESSION'
`Com_alter_table'             numeric        `GLOBAL' |
                                             `SESSION'
`Com_analyze'                 numeric        `GLOBAL' |
                                             `SESSION'
`Com_backup_table'            numeric        `GLOBAL' |
                                             `SESSION'
`Com_begin'                   numeric        `GLOBAL' |
                                             `SESSION'
`Com_call_procedure'          numeric        `GLOBAL' |
                                             `SESSION'
`Com_change_db'               numeric        `GLOBAL' |
                                             `SESSION'
`Com_change_master'           numeric        `GLOBAL' |
                                             `SESSION'
`Com_check'                   numeric        `GLOBAL' |
                                             `SESSION'
`Com_checksum'                numeric        `GLOBAL' |
                                             `SESSION'
`Com_commit'                  numeric        `GLOBAL' |
                                             `SESSION'
`Com_create_db'               numeric        `GLOBAL' |
                                             `SESSION'
`Com_create_event'            numeric        `GLOBAL' |
                                             `SESSION'
`Com_create_function'         numeric        `GLOBAL' |
                                             `SESSION'
`Com_create_index'            numeric        `GLOBAL' |
                                             `SESSION'
`Com_create_table'            numeric        `GLOBAL' |
                                             `SESSION'
`Com_create_user'             numeric        `GLOBAL' |
                                             `SESSION'
`Com_dealloc_sql'             numeric        `GLOBAL' |
                                             `SESSION'
`Com_delete'                  numeric        `GLOBAL' |
                                             `SESSION'
`Com_delete_multi'            numeric        `GLOBAL' |
                                             `SESSION'
`Com_do'                      numeric        `GLOBAL' |
                                             `SESSION'
`Com_drop_db'                 numeric        `GLOBAL' |
                                             `SESSION'
`Com_drop_event'              numeric        `GLOBAL' |
                                             `SESSION'
`Com_drop_function'           numeric        `GLOBAL' |
                                             `SESSION'
`Com_drop_index'              numeric        `GLOBAL' |
                                             `SESSION'
`Com_drop_table'              numeric        `GLOBAL' |
                                             `SESSION'
`Com_drop_user'               numeric        `GLOBAL' |
                                             `SESSION'
`Com_execute_sql'             numeric        `GLOBAL' |
                                             `SESSION'
`Com_flush'                   numeric        `GLOBAL' |
                                             `SESSION'
`Com_grant'                   numeric        `GLOBAL' |
                                             `SESSION'
`Com_ha_close'                numeric        `GLOBAL' |
                                             `SESSION'
`Com_ha_open'                 numeric        `GLOBAL' |
                                             `SESSION'
`Com_ha_read'                 numeric        `GLOBAL' |
                                             `SESSION'
`Com_help'                    numeric        `GLOBAL' |
                                             `SESSION'
`Com_insert'                  numeric        `GLOBAL' |
                                             `SESSION'
`Com_insert_select'           numeric        `GLOBAL' |
                                             `SESSION'
`Com_kill'                    numeric        `GLOBAL' |
                                             `SESSION'
`Com_load'                    numeric        `GLOBAL' |
                                             `SESSION'
`Com_lock_tables'             numeric        `GLOBAL' |
                                             `SESSION'
`Com_optimize'                numeric        `GLOBAL' |
                                             `SESSION'
`Com_preload_keys'            numeric        `GLOBAL' |
                                             `SESSION'
`Com_prepare_sql'             numeric        `GLOBAL' |
                                             `SESSION'
`Com_purge'                   numeric        `GLOBAL' |
                                             `SESSION'
`Com_purge_before_date'       numeric        `GLOBAL' |
                                             `SESSION'
`Com_rename_table'            numeric        `GLOBAL' |
                                             `SESSION'
`Com_repair'                  numeric        `GLOBAL' |
                                             `SESSION'
`Com_replace'                 numeric        `GLOBAL' |
                                             `SESSION'
`Com_replace_select'          numeric        `GLOBAL' |
                                             `SESSION'
`Com_reset'                   numeric        `GLOBAL' |
                                             `SESSION'
`Com_restore_table'           numeric        `GLOBAL' |
                                             `SESSION'
`Com_revoke'                  numeric        `GLOBAL' |
                                             `SESSION'
`Com_revoke_all'              numeric        `GLOBAL' |
                                             `SESSION'
`Com_rollback'                numeric        `GLOBAL' |
                                             `SESSION'
`Com_savepoint'               numeric        `GLOBAL' |
                                             `SESSION'
`Com_select'                  numeric        `GLOBAL' |
                                             `SESSION'
`Com_set_option'              numeric        `GLOBAL' |
                                             `SESSION'
`Com_show_binlog_events'      numeric        `GLOBAL' |
                                             `SESSION'
`Com_show_binlogs'            numeric        `GLOBAL' |
                                             `SESSION'
`Com_show_charsets'           numeric        `GLOBAL' |
                                             `SESSION'
`Com_show_collations'         numeric        `GLOBAL' |
                                             `SESSION'
`Com_show_column_types'       numeric        `GLOBAL' |
                                             `SESSION'
`Com_show_create_db'          numeric        `GLOBAL' |
                                             `SESSION'
`Com_show_create_event'       numeric        `GLOBAL' |
                                             `SESSION'
`Com_show_create_table'       numeric        `GLOBAL' |
                                             `SESSION'
`Com_show_databases'          numeric        `GLOBAL' |
                                             `SESSION'
`Com_show_engine_logs'        numeric        `GLOBAL' |
                                             `SESSION'
`Com_show_engine_mutex'       numeric        `GLOBAL' |
                                             `SESSION'
`Com_show_engine_status'      numeric        `GLOBAL' |
                                             `SESSION'
`Com_show_errors'             numeric        `GLOBAL' |
                                             `SESSION'
`Com_show_events'             numeric        `GLOBAL' |
                                             `SESSION'
`Com_show_fields'             numeric        `GLOBAL' |
                                             `SESSION'
`Com_show_grants'             numeric        `GLOBAL' |
                                             `SESSION'
`Com_show_innodb_status'      numeric        `GLOBAL' |
                                             `SESSION'
`Com_show_keys'               numeric        `GLOBAL' |
                                             `SESSION'
`Com_show_logs'               numeric        `GLOBAL' |
                                             `SESSION'
`Com_show_master_status'      numeric        `GLOBAL' |
                                             `SESSION'
`Com_show_ndb_status'         numeric        `GLOBAL' |
                                             `SESSION'
`Com_show_new_master'         numeric        `GLOBAL' |
                                             `SESSION'
`Com_show_open_tables'        numeric        `GLOBAL' |
                                             `SESSION'
`Com_show_plugins'            numeric        `GLOBAL' |
                                             `SESSION'
`Com_show_privileges'         numeric        `GLOBAL' |
                                             `SESSION'
`Com_show_processlist'        numeric        `GLOBAL' |
                                             `SESSION'
`Com_show_slave_hosts'        numeric        `GLOBAL' |
                                             `SESSION'
`Com_show_slave_status'       numeric        `GLOBAL' |
                                             `SESSION'
`Com_show_status'             numeric        `GLOBAL' |
                                             `SESSION'
`Com_show_storage_engines'    numeric        `GLOBAL' |
                                             `SESSION'
`Com_show_tables'             numeric        `GLOBAL' |
                                             `SESSION'
`Com_show_triggers'           numeric        `GLOBAL' |
                                             `SESSION'
`Com_show_variables'          numeric        `GLOBAL' |
                                             `SESSION'
`Com_show_warnings'           numeric        `GLOBAL' |
                                             `SESSION'
`Com_slave_start'             numeric        `GLOBAL' |
                                             `SESSION'
`Com_slave_stop'              numeric        `GLOBAL' |
                                             `SESSION'
`Com_stmt_close'              numeric        `GLOBAL' |
                                             `SESSION'
`Com_stmt_execute'            numeric        `GLOBAL' |
                                             `SESSION'
`Com_stmt_fetch'              numeric        `GLOBAL' |
                                             `SESSION'
`Com_stmt_prepare'            numeric        `GLOBAL' |
                                             `SESSION'
`Com_stmt_reset'              numeric        `GLOBAL' |
                                             `SESSION'
`Com_stmt_send_long_data'     numeric        `GLOBAL' |
                                             `SESSION'
`Com_truncate'                numeric        `GLOBAL' |
                                             `SESSION'
`Com_unlock_tables'           numeric        `GLOBAL' |
                                             `SESSION'
`Com_update'                  numeric        `GLOBAL' |
                                             `SESSION'
`Com_update_multi'            numeric        `GLOBAL' |
                                             `SESSION'
`Com_xa_commit'               numeric        `GLOBAL' |
                                             `SESSION'
`Com_xa_end'                  numeric        `GLOBAL' |
                                             `SESSION'
`Com_xa_prepare'              numeric        `GLOBAL' |
                                             `SESSION'
`Com_xa_recover'              numeric        `GLOBAL' |
                                             `SESSION'
`Com_xa_rollback'             numeric        `GLOBAL' |
                                             `SESSION'
`Com_xa_start'                numeric        `GLOBAL' |
                                             `SESSION'
`Compression'                 numeric        `SESSION'
`Connections'                 numeric        `GLOBAL'
`Created_tmp_disk_tables'     numeric        `GLOBAL' |
                                             `SESSION'
`Created_tmp_files'           numeric        `GLOBAL'
`Created_tmp_tables'          numeric        `GLOBAL' |
                                             `SESSION'
`Delayed_errors'              numeric        `GLOBAL'
`Delayed_insert_threads'      numeric        `GLOBAL'
`Delayed_writes'              numeric        `GLOBAL'
`Flush_commands'              numeric        `GLOBAL'
`Handler_commit'              numeric        `GLOBAL' |
                                             `SESSION'
`Handler_delete'              numeric        `GLOBAL' |
                                             `SESSION'
`Handler_discover'            numeric        `GLOBAL' |
                                             `SESSION'
`Handler_prepare'             numeric        `GLOBAL' |
                                             `SESSION'
`Handler_read_first'          numeric        `GLOBAL' |
                                             `SESSION'
`Handler_read_key'            numeric        `GLOBAL' |
                                             `SESSION'
`Handler_read_next'           numeric        `GLOBAL' |
                                             `SESSION'
`Handler_read_prev'           numeric        `GLOBAL' |
                                             `SESSION'
`Handler_read_rnd'            numeric        `GLOBAL' |
                                             `SESSION'
`Handler_read_rnd_next'       numeric        `GLOBAL' |
                                             `SESSION'
`Handler_rollback'            numeric        `GLOBAL' |
                                             `SESSION'
`Handler_savepoint'           numeric        `GLOBAL' |
                                             `SESSION'
`Handler_savepoint_rollback'  numeric        `GLOBAL' |
                                             `SESSION'
`Handler_update'              numeric        `GLOBAL' |
                                             `SESSION'
`Handler_write'               numeric        `GLOBAL' |
                                             `SESSION'
`Innodb_buffer_pool_pages_data'numeric        `GLOBAL'
`Innodb_buffer_pool_pages_dirty'numeric        `GLOBAL'
`Innodb_buffer_pool_pages_flushed'numeric        `GLOBAL'
`Innodb_buffer_pool_pages_free'numeric        `GLOBAL'
`Innodb_buffer_pool_pages_latched'numeric        `GLOBAL'
`Innodb_buffer_pool_pages_misc'numeric        `GLOBAL'
`Innodb_buffer_pool_pages_total'numeric        `GLOBAL'
`Innodb_buffer_pool_read_ahead_rnd'numeric        `GLOBAL'
`Innodb_buffer_pool_read_ahead_seq'numeric        `GLOBAL'
`Innodb_buffer_pool_read_requests'numeric        `GLOBAL'
`Innodb_buffer_pool_reads'    numeric        `GLOBAL'
`Innodb_buffer_pool_wait_free'numeric        `GLOBAL'
`Innodb_buffer_pool_write_requests'numeric        `GLOBAL'
`Innodb_data_fsyncs'          numeric        `GLOBAL'
`Innodb_data_pending_fsyncs'  numeric        `GLOBAL'
`Innodb_data_pending_reads'   numeric        `GLOBAL'
`Innodb_data_pending_writes'  numeric        `GLOBAL'
`Innodb_data_read'            numeric        `GLOBAL'
`Innodb_data_reads'           numeric        `GLOBAL'
`Innodb_data_writes'          numeric        `GLOBAL'
`Innodb_data_written'         numeric        `GLOBAL'
`Innodb_dblwr_pages_written'  numeric        `GLOBAL'
`Innodb_dblwr_writes'         numeric        `GLOBAL'
`Innodb_log_waits'            numeric        `GLOBAL'
`Innodb_log_write_requests'   numeric        `GLOBAL'
`Innodb_log_writes'           numeric        `GLOBAL'
`Innodb_os_log_fsyncs'        numeric        `GLOBAL'
`Innodb_os_log_pending_fsyncs'numeric        `GLOBAL'
`Innodb_os_log_pending_writes'numeric        `GLOBAL'
`Innodb_os_log_written'       numeric        `GLOBAL'
`Innodb_page_size'            numeric        `GLOBAL'
`Innodb_pages_created'        numeric        `GLOBAL'
`Innodb_pages_read'           numeric        `GLOBAL'
`Innodb_pages_written'        numeric        `GLOBAL'
`Innodb_row_lock_current_waits'numeric        `GLOBAL'
`Innodb_row_lock_time'        numeric        `GLOBAL'
`Innodb_row_lock_time_avg'    numeric        `GLOBAL'
`Innodb_row_lock_time_max'    numeric        `GLOBAL'
`Innodb_row_lock_waits'       numeric        `GLOBAL'
`Innodb_rows_deleted'         numeric        `GLOBAL'
`Innodb_rows_inserted'        numeric        `GLOBAL'
`Innodb_rows_read'            numeric        `GLOBAL'
`Innodb_rows_updated'         numeric        `GLOBAL'
`Key_blocks_not_flushed'      numeric        `GLOBAL'
`Key_blocks_unused'           numeric        `GLOBAL'
`Key_blocks_used'             numeric        `GLOBAL'
`Key_read_requests'           numeric        `GLOBAL'
`Key_reads'                   numeric        `GLOBAL'
`Key_write_requests'          numeric        `GLOBAL'
`Key_writes'                  numeric        `GLOBAL'
`Last_query_cost'             numeric        `SESSION'
`Max_used_connections'        numeric        `GLOBAL'
`Ndb_cluster_node_id'         numeric        `GLOBAL' |
                                             `SESSION'
`Ndb_config_from_host'        numeric        `GLOBAL' |
                                             `SESSION'
`Ndb_config_from_port'        numeric        `GLOBAL' |
                                             `SESSION'
`ndb-nodeid'                  numeric        `GLOBAL'
`Not_flushed_delayed_rows'    numeric        `GLOBAL'
`Open_files'                  numeric        `GLOBAL'
`Open_streams'                numeric        `GLOBAL'
`Open_tables'                 numeric        `GLOBAL' |
                                             `SESSION'
`Opened_tables'               numeric        `GLOBAL' |
                                             `SESSION'
`Prepared_stmt_count'         numeric        `GLOBAL'
`Qcache_free_blocks'          numeric        `GLOBAL'
`Qcache_free_memory'          numeric        `GLOBAL'
`Qcache_hits'                 numeric        `GLOBAL'
`Qcache_inserts'              numeric        `GLOBAL'
`Qcache_lowmem_prunes'        numeric        `GLOBAL'
`Qcache_not_cached'           numeric        `GLOBAL'
`Qcache_queries_in_cache'     numeric        `GLOBAL'
`Qcache_total_blocks'         numeric        `GLOBAL'
`Queries'                     numeric        `GLOBAL' |
                                             `SESSION'
`Questions'                   numeric        `GLOBAL' |
                                             `SESSION'
`Rpl_status'                  string         `GLOBAL'
`Select_full_join'            numeric        `GLOBAL' |
                                             `SESSION'
`Select_full_range_join'      numeric        `GLOBAL' |
                                             `SESSION'
`Select_range'                numeric        `GLOBAL' |
                                             `SESSION'
`Select_range_check'          numeric        `GLOBAL' |
                                             `SESSION'
`Select_scan'                 numeric        `GLOBAL' |
                                             `SESSION'
`Slave_open_temp_tables'      numeric        `GLOBAL'
`Slave_retried_transactions'  numeric        `GLOBAL'
`Slave_running'               boolean        `GLOBAL'
`Slow_launch_threads'         numeric        `GLOBAL' |
                                             `SESSION'
`Slow_queries'                numeric        `GLOBAL' |
                                             `SESSION'
`Sort_merge_passes'           numeric        `GLOBAL' |
                                             `SESSION'
`Sort_range'                  numeric        `GLOBAL' |
                                             `SESSION'
`Sort_rows'                   numeric        `GLOBAL' |
                                             `SESSION'
`Sort_scan'                   numeric        `GLOBAL' |
                                             `SESSION'
`Ssl_accept_renegotiates'     numeric        `GLOBAL'
`Ssl_accepts'                 numeric        `GLOBAL'
`Ssl_callback_cache_hits'     numeric        `GLOBAL'
`Ssl_cipher'                  string         `GLOBAL' |
                                             `SESSION'
`Ssl_cipher_list'             string         `GLOBAL' |
                                             `SESSION'
`Ssl_client_connects'         numeric        `GLOBAL'
`Ssl_connect_renegotiates'    numeric        `GLOBAL'
`Ssl_ctx_verify_depth'        numeric        `GLOBAL'
`Ssl_ctx_verify_mode'         numeric        `GLOBAL'
`Ssl_default_timeout'         numeric        `GLOBAL' |
                                             `SESSION'
`Ssl_finished_accepts'        numeric        `GLOBAL'
`Ssl_finished_connects'       numeric        `GLOBAL'
`Ssl_session_cache_hits'      numeric        `GLOBAL'
`Ssl_session_cache_misses'    numeric        `GLOBAL'
`Ssl_session_cache_mode'      string         `GLOBAL'
`Ssl_session_cache_overflows' numeric        `GLOBAL'
`Ssl_session_cache_size'      numeric        `GLOBAL'
`Ssl_session_cache_timeouts'  numeric        `GLOBAL'
`Ssl_sessions_reused'         numeric        `GLOBAL' |
                                             `SESSION'
`Ssl_used_session_cache_entries'numeric        `GLOBAL'
`Ssl_verify_depth'            numeric        `GLOBAL' |
                                             `SESSION'
`Ssl_verify_mode'             numeric        `GLOBAL' |
                                             `SESSION'
`Ssl_version'                 string         `GLOBAL' |
                                             `SESSION'
`Table_locks_immediate'       numeric        `GLOBAL'
`Table_locks_waited'          numeric        `GLOBAL'
`Tc_log_max_pages_used'       numeric        `GLOBAL'
`Tc_log_page_size'            numeric        `GLOBAL'
`Tc_log_page_waits'           numeric        `GLOBAL'
`Threads_cached'              numeric        `GLOBAL'
`Threads_connected'           numeric        `GLOBAL'
`Threads_created'             numeric        `GLOBAL'
`Threads_running'             numeric        `GLOBAL'
`Uptime'                      numeric        `GLOBAL'
`Uptime_since_flush_status'   numeric        `GLOBAL'

*Note*:

Before MySQL 5.0.2, *Note `SHOW STATUS': show-status.  returned global
status values. Because the default as of 5.0.2 is to return session
values, this is incompatible with previous versions. To issue a *Note
`SHOW STATUS': show-status.  statement that will retrieve global status
values for all versions of MySQL, write it like this:

     SHOW /*!50002 GLOBAL */ STATUS;

Many status variables are reset to 0 by the `FLUSH STATUS' statement.

The status variables have the following meanings. Variables with no
version indicated were already present prior to MySQL 5.0. For
information regarding their implementation history, see `MySQL 3.23,
4.0, 4.1 Reference Manual'.

For meanings of status variables specific to MySQL Cluster, see *Note
mysql-cluster-status-variables::.

   *  `Aborted_clients'

     The number of connections that were aborted because the client
     died without closing the connection properly. See *Note
     communication-errors::.

   *  `Aborted_connects'

     The number of failed attempts to connect to the MySQL server.  See
     *Note communication-errors::.

   *  `Binlog_cache_disk_use'

     The number of transactions that used the temporary binary log
     cache but that exceeded the value of `binlog_cache_size' and used a
     temporary file to store statements from the transaction.

   *  `Binlog_cache_use'

     The number of transactions that used the temporary binary log
     cache.

   *  `Bytes_received'

     The number of bytes received from all clients.

   *  `Bytes_sent'

     The number of bytes sent to all clients.

   *  `Com_XXX'

     The `Com_XXX' statement counter variables indicate the number of
     times each XXX statement has been executed.  There is one status
     variable for each type of statement. For example, `Com_delete' and
     `Com_insert' count *Note `DELETE': delete. and *Note `INSERT':
     insert. statements, respectively. However, if a query result is
     returned from query cache, the server increments the `Qcache_hits'
     status variable, not `Com_select'. See *Note
     query-cache-status-and-maintenance::.

     All of the `Com_stmt_XXX' variables are increased even if a
     prepared statement argument is unknown or an error occurred during
     execution. In other words, their values correspond to the number
     of requests issued, not to the number of requests successfully
     completed.

     The `Com_stmt_XXX' status variables were added in 5.0.8:

        * `Com_stmt_prepare'

        * `Com_stmt_execute'

        * `Com_stmt_fetch'

        * `Com_stmt_send_long_data'

        * `Com_stmt_reset'

        * `Com_stmt_close'

     Those variables stand for prepared statement commands. Their names
     refer to the `COM_XXX' command set used in the network layer. In
     other words, their values increase whenever prepared statement API
     calls such as `mysql_stmt_prepare()', `mysql_stmt_execute()', and
     so forth are executed. However, `Com_stmt_prepare',
     `Com_stmt_execute' and `Com_stmt_close' also increase for *Note
     `PREPARE': prepare, *Note `EXECUTE': execute, or *Note `DEALLOCATE
     PREPARE': deallocate-prepare, respectively. Additionally, the
     values of the older statement counter variables `Com_prepare_sql',
     `Com_execute_sql', and `Com_dealloc_sql' increase for the *Note
     `PREPARE': prepare, *Note `EXECUTE': execute, and *Note
     `DEALLOCATE PREPARE': deallocate-prepare. statements.
     `Com_stmt_fetch' stands for the total number of network
     round-trips issued when fetching from cursors.

   *  `Compression'

     Whether the client connection uses compression in the
     client/server protocol. Added in MySQL 5.0.16.

   *  `Connections'

     The number of connection attempts (successful or not) to the MySQL
     server.

   *  `Created_tmp_disk_tables'

     The number of internal on-disk temporary tables created by the
     server while executing statements.

     If an internal temporary table is created initially as an
     in-memory table but becomes too large, MySQL automatically
     converts it to an on-disk table. The maximum size for in-memory
     temporary tables is the minimum of the `tmp_table_size' and
     `max_heap_table_size' values.  If `Created_tmp_disk_tables' is
     large, you may want to increase the `tmp_table_size' or
     `max_heap_table_size' values.  value to lessen the likelihood that
     internal temporary tables in memory will be converted to on-disk
     tables.

     You can compare the number of internal on-disk temporary tables
     created to the total number of internal temporary tables created
     by comparing the values of the `Created_tmp_disk_tables' and
     `Created_tmp_tables' variables.

     See also *Note internal-temporary-tables::.

   *  `Created_tmp_files'

     How many temporary files *Note `mysqld': mysqld. has created.

   *  `Created_tmp_tables'

     The number of internal temporary tables created by the server
     while executing statements.

     You can compare the number of internal on-disk temporary tables
     created to the total number of internal temporary tables created
     by comparing the values of the `Created_tmp_disk_tables' and
     `Created_tmp_tables' variables.

     See also *Note internal-temporary-tables::.

   *  `Delayed_errors'

     The number of rows written with *Note `INSERT DELAYED':
     insert-delayed. for which some error occurred (probably `duplicate
     key').

   *  `Delayed_insert_threads'

     The number of *Note `INSERT DELAYED': insert-delayed.  handler
     threads in use.

   *  `Delayed_writes'

     The number of *Note `INSERT DELAYED': insert-delayed.  rows
     written.

   *  `Flush_commands'

     The number of times the server flushes tables, whether because a
     user executed a *Note `FLUSH TABLES': flush. statement or due to
     internal server operation. It is also incremented by receipt of a
     `COM_REFRESH' packet. This is in contrast to `Com_flush', which
     indicates how many `FLUSH' statements have been executed, whether
     *Note `FLUSH TABLES': flush, *Note `FLUSH LOGS': flush, and so
     forth.

   *  `Handler_commit'

     The number of internal *Note `COMMIT': commit.  statements.

   *  `Handler_delete'

     The number of times that rows have been deleted from tables.

   *  `Handler_prepare'

     A counter for the prepare phase of two-phase commit operations.
     Added in MySQL 5.0.3.

   *  `Handler_read_first'

     The number of times the first entry in an index was read. If this
     value is high, it suggests that the server is doing a lot of full
     index scans; for example, `SELECT col1 FROM foo', assuming that
     `col1' is indexed.

   *  `Handler_read_key'

     The number of requests to read a row based on a key. If this value
     is high, it is a good indication that your tables are properly
     indexed for your queries.

   *  `Handler_read_next'

     The number of requests to read the next row in key order. This
     value is incremented if you are querying an index column with a
     range constraint or if you are doing an index scan.

   *  `Handler_read_prev'

     The number of requests to read the previous row in key order.
     This read method is mainly used to optimize `ORDER BY ... DESC'.

   *  `Handler_read_rnd'

     The number of requests to read a row based on a fixed position.
     This value is high if you are doing a lot of queries that require
     sorting of the result. You probably have a lot of queries that
     require MySQL to scan entire tables or you have joins that do not
     use keys properly.

   *  `Handler_read_rnd_next'

     The number of requests to read the next row in the data file.
     This value is high if you are doing a lot of table scans.
     Generally this suggests that your tables are not properly indexed
     or that your queries are not written to take advantage of the
     indexes you have.

   *  `Handler_rollback'

     The number of requests for a storage engine to perform a rollback
     operation.

   *  `Handler_savepoint'

     The number of requests for a storage engine to place a savepoint.
     Added in MySQL 5.0.3.

   *  `Handler_savepoint_rollback'

     The number of requests for a storage engine to roll back to a
     savepoint. Added in MySQL 5.0.3.

   *  `Handler_update'

     The number of requests to update a row in a table.

   *  `Handler_write'

     The number of requests to insert a row in a table.

   *  `Innodb_buffer_pool_pages_data'

     The number of pages containing data (dirty or clean). Added in
     MySQL 5.0.2.

   *  `Innodb_buffer_pool_pages_dirty'

     The number of pages currently dirty. Added in MySQL 5.0.2.

   *  `Innodb_buffer_pool_pages_flushed'

     The number of buffer pool page-flush requests. Added in MySQL
     5.0.2.

   *  `Innodb_buffer_pool_pages_free'

     The number of free pages. Added in MySQL 5.0.2.

   *  `Innodb_buffer_pool_pages_latched'

     The number of latched pages in `InnoDB' buffer pool. These are
     pages currently being read or written or that cannot be flushed or
     removed for some other reason.  Added in MySQL 5.0.2. Calculation
     of this variable is expensive, so as of MySQL 5.0.68, it is
     available only when the `UNIV_DEBUG' system is defined at server
     build time.

   *  `Innodb_buffer_pool_pages_misc'

     The number of pages that are busy because they have been allocated
     for administrative overhead such as row locks or the adaptive hash
     index. This value can also be calculated as
     `Innodb_buffer_pool_pages_total' - `Innodb_buffer_pool_pages_free'
     - `Innodb_buffer_pool_pages_data'.  Added in MySQL 5.0.2.

   *  `Innodb_buffer_pool_pages_total'

     The total size of buffer pool, in pages. Added in MySQL 5.0.2.

   *  `Innodb_buffer_pool_read_ahead_rnd'

     The number of `random' read-aheads initiated by `InnoDB'. This
     happens when a query scans a large portion of a table but in
     random order. Added in MySQL 5.0.2.

   *  `Innodb_buffer_pool_read_ahead_seq'

     The number of sequential read-aheads initiated by `InnoDB'. This
     happens when `InnoDB' does a sequential full table scan.  Added in
     MySQL 5.0.2.

   *  `Innodb_buffer_pool_read_requests'

     The number of logical read requests `InnoDB' has done. Added in
     MySQL 5.0.2.

   *  `Innodb_buffer_pool_reads'

     The number of logical reads that `InnoDB' could not satisfy from
     the buffer pool, and had to read directly from the disk.

   *  `Innodb_buffer_pool_wait_free'

     Normally, writes to the `InnoDB' buffer pool happen in the
     background. However, if it is necessary to read or create a page
     and no clean pages are available, it is also necessary to wait for
     pages to be flushed first. This counter counts instances of these
     waits. If the buffer pool size has been set properly, this value
     should be small. Added in MySQL 5.0.2.

   *  `Innodb_buffer_pool_write_requests'

     The number writes done to the `InnoDB' buffer pool. Added in MySQL
     5.0.2.

   *  `Innodb_data_fsyncs'

     The number of `fsync()' operations so far.  Added in MySQL 5.0.2.

   *  `Innodb_data_pending_fsyncs'

     The current number of pending `fsync()' operations. Added in MySQL
     5.0.2.

   *  `Innodb_data_pending_reads'

     The current number of pending reads. Added in MySQL 5.0.2.

   *  `Innodb_data_pending_writes'

     The current number of pending writes. Added in MySQL 5.0.2.

   *  `Innodb_data_read'

     The amount of data read since the server was started. Added in
     MySQL 5.0.2.

   *  `Innodb_data_reads'

     The total number of data reads. Added in MySQL 5.0.2.

   *  `Innodb_data_writes'

     The total number of data writes. Added in MySQL 5.0.2.

   *  `Innodb_data_written'

     The amount of data written so far, in bytes. Added in MySQL 5.0.2.

   *  `Innodb_dblwr_pages_written'

     The number of pages that have been written for doublewrite
     operations. Added in MySQL 5.0.2. See *Note innodb-disk-io::.

   *  `Innodb_dblwr_writes'

     The number of doublewrite operations that have been performed.
     Added in MySQL 5.0.2. See *Note innodb-disk-io::.

   *  `Innodb_log_waits'

     The number of times that the log buffer was too small and a wait
     was required for it to be flushed before continuing.  Added in
     MySQL 5.0.2.

   *  `Innodb_log_write_requests'

     The number of log write requests. Added in MySQL 5.0.2.

   *  `Innodb_log_writes'

     The number of physical writes to the log file. Added in MySQL
     5.0.2.

   *  `Innodb_os_log_fsyncs'

     The number of `fsync()' writes done to the log file. Added in
     MySQL 5.0.2.

   *  `Innodb_os_log_pending_fsyncs'

     The number of pending log file `fsync()' operations. Added in
     MySQL 5.0.2.

   *  `Innodb_os_log_pending_writes'

     The number of pending log file writes. Added in MySQL 5.0.2.

   *  `Innodb_os_log_written'

     The number of bytes written to the log file. Added in MySQL 5.0.2.

   *  `Innodb_page_size'

     The compiled-in `InnoDB' page size (default 16KB). Many values are
     counted in pages; the page size permits them to be easily
     converted to bytes. Added in MySQL 5.0.2.

   *  `Innodb_pages_created'

     The number of pages created. Added in MySQL 5.0.2.

   *  `Innodb_pages_read'

     The number of pages read. Added in MySQL 5.0.2.

   *  `Innodb_pages_written'

     The number of pages written. Added in MySQL 5.0.2.

   *  `Innodb_row_lock_current_waits'

     The number of row locks currently being waited for. Added in MySQL
     5.0.3.

   *  `Innodb_row_lock_time'

     The total time spent in acquiring row locks, in milliseconds.
     Added in MySQL 5.0.3.

   *  `Innodb_row_lock_time_avg'

     The average time to acquire a row lock, in milliseconds. Added in
     MySQL 5.0.3.

   *  `Innodb_row_lock_time_max'

     The maximum time to acquire a row lock, in milliseconds. Added in
     MySQL 5.0.3.

   *  `Innodb_row_lock_waits'

     The number of times a row lock had to be waited for. Added in
     MySQL 5.0.3.

   *  `Innodb_rows_deleted'

     The number of rows deleted from `InnoDB' tables. Added in MySQL
     5.0.2.

   *  `Innodb_rows_inserted'

     The number of rows inserted into `InnoDB' tables. Added in MySQL
     5.0.2.

   *  `Innodb_rows_read'

     The number of rows read from `InnoDB' tables.  Added in MySQL
     5.0.2.

   *  `Innodb_rows_updated'

     The number of rows updated in `InnoDB' tables. Added in MySQL
     5.0.2.

   *  `Key_blocks_not_flushed'

     The number of key blocks in the key cache that have changed but
     have not yet been flushed to disk.

   *  `Key_blocks_unused'

     The number of unused blocks in the key cache. You can use this
     value to determine how much of the key cache is in use; see the
     discussion of `key_buffer_size' in *Note server-system-variables::.

   *  `Key_blocks_used'

     The number of used blocks in the key cache. This value is a
     high-water mark that indicates the maximum number of blocks that
     have ever been in use at one time.

   *  `Key_read_requests'

     The number of requests to read a key block from the cache.

   *  `Key_reads'

     The number of physical reads of a key block from disk. If
     `Key_reads' is large, then your `key_buffer_size' value is
     probably too small. The cache miss rate can be calculated as
     `Key_reads'/`Key_read_requests'.

   *  `Key_write_requests'

     The number of requests to write a key block to the cache.

   *  `Key_writes'

     The number of physical writes of a key block to disk.

   *  `Last_query_cost'

     The total cost of the last compiled query as computed by the query
     optimizer. This is useful for comparing the cost of different
     query plans for the same query. The default value of 0 means that
     no query has been compiled yet. This variable was added in MySQL
     5.0.1, with a default value of -1. In MySQL 5.0.7, the default was
     changed to 0; also in version 5.0.7, the scope of `Last_query_cost'
     was changed to session rather than global.

     The `Last_query_cost' value can be computed accurately only for
     simple `flat' queries, not complex queries such as those with
     subqueries or *Note `UNION': union. For the latter, the value is
     set to 0.

     Prior to MySQL 5.0.16, this variable was not updated for queries
     served from the query cache.

   *  `Max_used_connections'

     The maximum number of connections that have been in use
     simultaneously since the server started.

   *  `Not_flushed_delayed_rows'

     The number of rows waiting to be written in *Note `INSERT
     DELAYED': insert-delayed. queues.

   *  `Open_files'

     The number of files that are open. This count includes regular
     files opened by the server. It does not include other types of
     files such as sockets or pipes. Also, the count does not include
     files that storage engines open using their own internal functions
     rather than asking the server level to do so.

   *  `Open_streams'

     The number of streams that are open (used mainly for logging).

   *  `Open_tables'

     The number of tables that are open.

   *  `Opened_tables'

     The number of tables that have been opened. If `Opened_tables' is
     big, your `table_cache' value is probably too small.

   *  `Prepared_stmt_count'

     The current number of prepared statements. (The maximum number of
     statements is given by the `max_prepared_stmt_count' system
     variable.) This variable was added in MySQL 5.0.32.

   *  `Qcache_free_blocks'

     The number of free memory blocks in the query cache.

   *  `Qcache_free_memory'

     The amount of free memory for the query cache.

   *  `Qcache_hits'

     The number of query cache hits.

   *  `Qcache_inserts'

     The number of queries added to the query cache.

   *  `Qcache_lowmem_prunes'

     The number of queries that were deleted from the query cache
     because of low memory.

   *  `Qcache_not_cached'

     The number of noncached queries (not cacheable, or not cached due
     to the `query_cache_type' setting).

   *  `Qcache_queries_in_cache'

     The number of queries registered in the query cache.

   *  `Qcache_total_blocks'

     The total number of blocks in the query cache.

   *  `Queries'

     The number of statements executed by the server. This variable
     includes statements executed within stored programs, unlike the
     `Questions' variable. It does not count `COM_PING' or
     `COM_STATISTICS' commands. This variable was added in MySQL 5.0.76.

   *  `Questions'

     The number of statements executed by the server. As of MySQL
     5.0.72, this includes only statements sent to the server by
     clients and no longer includes statements executed within stored
     programs, unlike the `Queries' variable. This variable does not
     count `COM_PING', `COM_STATISTICS', `COM_STMT_PREPARE',
     `COM_STMT_CLOSE', or `COM_STMT_RESET' commands.

   *  `Rpl_status'

     The status of fail-safe replication (not implemented). This
     variable is unused and is removed in MySQL 5.6.

   *  `Select_full_join'

     The number of joins that perform table scans because they do not
     use indexes. If this value is not 0, you should carefully check
     the indexes of your tables.

   *  `Select_full_range_join'

     The number of joins that used a range search on a reference table.

   *  `Select_range'

     The number of joins that used ranges on the first table. This is
     normally not a critical issue even if the value is quite large.

   *  `Select_range_check'

     The number of joins without keys that check for key usage after
     each row. If this is not 0, you should carefully check the indexes
     of your tables.

   *  `Select_scan'

     The number of joins that did a full scan of the first table.

   *  `Slave_open_temp_tables'

     The number of temporary tables that the slave SQL thread currently
     has open. If the value is greater than zero, it is not safe to
     shut down the slave; see *Note replication-features-temptables::.

   *  `Slave_retried_transactions'

     The total number of times since startup that the replication slave
     SQL thread has retried transactions. This variable was added in
     version 5.0.4.

   *  `Slave_running'

     This is `ON' if this server is a replication slave that is
     connected to a replication master, and both the I/O and SQL
     threads are running; otherwise, it is `OFF'.

   *  `Slow_launch_threads'

     The number of threads that have taken more than `slow_launch_time'
     seconds to create.

   *  `Slow_queries'

     The number of queries that have taken more than `long_query_time'
     seconds. See *Note slow-query-log::.

   *  `Sort_merge_passes'

     The number of merge passes that the sort algorithm has had to do.
     If this value is large, you should consider increasing the value
     of the `sort_buffer_size' system variable.

   *  `Sort_range'

     The number of sorts that were done using ranges.

   *  `Sort_rows'

     The number of sorted rows.

   *  `Sort_scan'

     The number of sorts that were done by scanning the table.

   *  `Ssl_accept_renegotiates'

     The number of negotiates needed to establish the connection.

   *  `Ssl_accepts'

     The number of accepted SSL connections.

   *  `Ssl_callback_cache_hits'

     The number of callback cache hits.

   *  `Ssl_cipher'

     The current SSL cipher (empty for non-SSL connections).

   *  `Ssl_cipher_list'

     The list of possible SSL ciphers.

   *  `Ssl_client_connects'

     The number of SSL connection attempts to an SSL-enabled master.

   *  `Ssl_connect_renegotiates'

     The number of negotiates needed to establish the connection to an
     SSL-enabled master.

   *  `Ssl_ctx_verify_depth'

     The SSL context verification depth (how many certificates in the
     chain are tested).

   *  `Ssl_ctx_verify_mode'

     The SSL context verification mode.

   *  `Ssl_default_timeout'

     The default SSL timeout.

   *  `Ssl_finished_accepts'

     The number of successful SSL connections to the server.

   *  `Ssl_finished_connects'

     The number of successful slave connections to an SSL-enabled
     master.

   *  `Ssl_session_cache_hits'

     The number of SSL session cache hits.

   *  `Ssl_session_cache_misses'

     The number of SSL session cache misses.

   *  `Ssl_session_cache_mode'

     The SSL session cache mode.

   *  `Ssl_session_cache_overflows'

     The number of SSL session cache overflows.

   *  `Ssl_session_cache_size'

     The SSL session cache size.

   *  `Ssl_session_cache_timeouts'

     The number of SSL session cache timeouts.

   *  `Ssl_sessions_reused'

     How many SSL connections were reused from the cache.

   *  `Ssl_used_session_cache_entries'

     How many SSL session cache entries were used.

   *  `Ssl_verify_depth'

     The verification depth for replication SSL connections.

   *  `Ssl_verify_mode'

     The verification mode for replication SSL connections.

   *  `Ssl_version'

     The SSL protocol version of the connection.

   *  `Table_locks_immediate'

     The number of times that a request for a table lock could be
     granted immediately.

   *  `Table_locks_waited'

     The number of times that a request for a table lock could not be
     granted immediately and a wait was needed. If this is high and you
     have performance problems, you should first optimize your queries,
     and then either split your table or tables or use replication.

   *  `Tc_log_max_pages_used'

     For the memory-mapped implementation of the log that is used by
     *Note `mysqld': mysqld. when it acts as the transaction
     coordinator for recovery of internal XA transactions, this
     variable indicates the largest number of pages used for the log
     since the server started. If the product of
     `Tc_log_max_pages_used' and `Tc_log_page_size' is always
     significantly less than the log size, the size is larger than
     necessary and can be reduced. (The size is set by the
     `--log-tc-size' option.  Currently, this variable is unused: It is
     unneeded for binary log-based recovery, and the memory-mapped
     recovery log method is not used unless the number of storage
     engines capable of two-phase commit is greater than one.
     (`InnoDB' is the only applicable engine.)  Added in MySQL 5.0.3.

   *  `Tc_log_page_size'

     The page size used for the memory-mapped implementation of the XA
     recovery log. The default value is determined using
     `getpagesize()'. Currently, this variable is unused for the same
     reasons as described for `Tc_log_max_pages_used'. Added in MySQL
     5.0.3.

   *  `Tc_log_page_waits'

     For the memory-mapped implementation of the recovery log, this
     variable increments each time the server was not able to commit a
     transaction and had to wait for a free page in the log. If this
     value is large, you might want to increase the log size (with the
     `--log-tc-size' option). For binary log-based recovery, this
     variable increments each time the binary log cannot be closed
     because there are two-phase commits in progress. (The close
     operation waits until all such transactions are finished.) Added
     in MySQL 5.0.3.

   *  `Threads_cached'

     The number of threads in the thread cache.

   *  `Threads_connected'

     The number of currently open connections.

   *  `Threads_created'

     The number of threads created to handle connections. If
     `Threads_created' is big, you may want to increase the
     `thread_cache_size' value. The cache miss rate can be calculated as
     `Threads_created'/`Connections'.

   *  `Threads_running'

     The number of threads that are not sleeping.

   *  `Uptime'

     The number of seconds that the server has been up.

   *  `Uptime_since_flush_status'

     The number of seconds since the most recent `FLUSH STATUS'
     statement. This variable was added in 5.0.35.  (MySQL Community
     only)


File: manual.info,  Node: server-sql-mode,  Next: server-side-help-support,  Prev: server-status-variables,  Up: mysqld-server

6.1.6 Server SQL Modes
----------------------

The MySQL server can operate in different SQL modes, and can apply
these modes differently for different clients. This capability enables
each application to tailor the server's operating mode to its own
requirements.

For answers to some questions that are often asked about server SQL
modes in MySQL, see *Note faqs-sql-modes::.

Modes define what SQL syntax MySQL should support and what kind of data
validation checks it should perform. This makes it easier to use MySQL
in different environments and to use MySQL together with other database
servers.

You can set the default SQL mode by starting *Note `mysqld': mysqld.
with the `--sql-mode="MODES"' option, or by using `sql-mode="MODES"' in
`my.cnf' (Unix operating systems) or `my.ini' (Windows).  MODES is a
list of different modes separated by comma (``,'') characters. The
default value is empty (no modes set). The MODES value also can be empty
(`--sql-mode=""' on the command line, or `sql-mode=""' in `my.cnf' on
Unix systems or in `my.ini' on Windows) if you want to clear it
explicitly.

You can change the SQL mode at runtime by using a `SET [GLOBAL|SESSION]
sql_mode='MODES'' statement to set the `sql_mode' system value.
Setting the `GLOBAL' variable requires the `SUPER' privilege and
affects the operation of all clients that connect from that time on.
Setting the `SESSION' variable affects only the current client. Any
client can change its own session `sql_mode' value at any time.

You can retrieve the current global or session `sql_mode' value with
the following statements:

     SELECT @@GLOBAL.sql_mode;
     SELECT @@SESSION.sql_mode;

The most important `sql_mode' values are probably these:

   * `ANSI'

     This mode changes syntax and behavior to conform more closely to
     standard SQL.

   * `STRICT_TRANS_TABLES'

     If a value could not be inserted as given into a transactional
     table, abort the statement. For a nontransactional table, abort
     the statement if the value occurs in a single-row statement or the
     first row of a multiple-row statement. More detail is given later
     in this section. (Implemented in MySQL 5.0.2)

   * `TRADITIONAL'

     Make MySQL behave like a `traditional' SQL database system. A
     simple description of this mode is `give an error instead of a
     warning' when inserting an incorrect value into a column.

     *Note*:

     The *Note `INSERT': insert./*Note `UPDATE': update.  aborts as
     soon as the error is noticed. This may not be what you want if you
     are using a nontransactional storage engine, because data changes
     made prior to the error may not be rolled back, resulting in a
     `partially done' update. (Added in MySQL 5.0.2)

When this manual refers to `strict mode,' it means a mode where at
least one of `STRICT_TRANS_TABLES' or `STRICT_ALL_TABLES' is enabled.

The following list describes all supported modes:

   *  `ALLOW_INVALID_DATES'

     Do not perform full checking of dates. Check only that the month
     is in the range from 1 to 12 and the day is in the range from 1 to
     31. This is very convenient for Web applications where you obtain
     year, month, and day in three different fields and you want to
     store exactly what the user inserted (without date validation).
     This mode applies to *Note `DATE': datetime. and *Note `DATETIME':
     datetime. columns. It does not apply *Note `TIMESTAMP': datetime.
     columns, which always require a valid date.

     This mode is implemented in MySQL 5.0.2. Before 5.0.2, this was
     the default MySQL date-handling mode. As of 5.0.2, the server
     requires that month and day values be legal, and not merely in the
     range 1 to 12 and 1 to 31, respectively. With strict mode
     disabled, invalid dates such as `'2004-04-31'' are converted to
     `'0000-00-00'' and a warning is generated.  With strict mode
     enabled, invalid dates generate an error. To permit such dates,
     enable `ALLOW_INVALID_DATES'.

   *  `ANSI_QUOTES'

     Treat ``"'' as an identifier quote character (like the ```'' quote
     character) and not as a string quote character. You can still use
     ```'' to quote identifiers with this mode enabled. With
     `ANSI_QUOTES' enabled, you cannot use double quotation marks to
     quote literal strings, because it is interpreted as an identifier.

   *  `ERROR_FOR_DIVISION_BY_ZERO'

     Produce an error in strict mode (otherwise a warning) when a
     division by zero (or `MOD(X,0)') occurs during an *Note `INSERT':
     insert. or *Note `UPDATE': update. If this mode is not enabled,
     MySQL instead returns `NULL' for divisions by zero. For *Note
     `INSERT IGNORE': insert. or `UPDATE IGNORE', MySQL generates a
     warning for divisions by zero, but the result of the operation is
     `NULL'. (Implemented in MySQL 5.0.2)

   *  `HIGH_NOT_PRECEDENCE'

     From MySQL 5.0.2 on, the precedence of the `NOT' operator is such
     that expressions such as `NOT a BETWEEN b AND c' are parsed as
     `NOT (a BETWEEN b AND c)'.  Before MySQL 5.0.2, the expression is
     parsed as `(NOT a) BETWEEN b AND c'. The old higher-precedence
     behavior can be obtained by enabling the `HIGH_NOT_PRECEDENCE' SQL
     mode. (Added in MySQL 5.0.2)

          mysql> SET sql_mode = '';
          mysql> SELECT NOT 1 BETWEEN -5 AND 5;
                  -> 0
          mysql> SET sql_mode = 'HIGH_NOT_PRECEDENCE';
          mysql> SELECT NOT 1 BETWEEN -5 AND 5;
                  -> 1

   *  `IGNORE_SPACE'

     Permit spaces between a function name and the ``('' character.
     This causes built-in function names to be treated as reserved
     words. As a result, identifiers that are the same as function
     names must be quoted as described in *Note identifiers::. For
     example, because there is a `COUNT()' function, the use of `count'
     as a table name in the following statement causes an error:

          mysql> CREATE TABLE count (i INT);
          ERROR 1064 (42000): You have an error in your SQL syntax

     The table name should be quoted:

          mysql> CREATE TABLE `count` (i INT);
          Query OK, 0 rows affected (0.00 sec)

     The `IGNORE_SPACE' SQL mode applies to built-in functions, not to
     user-defined functions or stored functions. It is always
     permissible to have spaces after a UDF or stored function name,
     regardless of whether `IGNORE_SPACE' is enabled.

     For further discussion of `IGNORE_SPACE', see *Note
     function-resolution::.

   *  `NO_AUTO_CREATE_USER'

     Prevent the *Note `GRANT': grant. statement from automatically
     creating new users if it would otherwise do so, unless a nonempty
     password also is specified. (Added in MySQL 5.0.2)

   *  `NO_AUTO_VALUE_ON_ZERO'

     `NO_AUTO_VALUE_ON_ZERO' affects handling of `AUTO_INCREMENT'
     columns.  Normally, you generate the next sequence number for the
     column by inserting either `NULL' or `0' into it.
     `NO_AUTO_VALUE_ON_ZERO' suppresses this behavior for `0' so that
     only `NULL' generates the next sequence number.

     This mode can be useful if `0' has been stored in a table's
     `AUTO_INCREMENT' column.  (Storing `0' is not a recommended
     practice, by the way.) For example, if you dump the table with
     *Note `mysqldump': mysqldump. and then reload it, MySQL normally
     generates new sequence numbers when it encounters the `0' values,
     resulting in a table with contents different from the one that was
     dumped. Enabling `NO_AUTO_VALUE_ON_ZERO' before reloading the dump
     file solves this problem.  *Note `mysqldump': mysqldump. now
     automatically includes in its output a statement that enables
     `NO_AUTO_VALUE_ON_ZERO', to avoid this problem.

   *  `NO_BACKSLASH_ESCAPES'

     Disable the use of the backslash character (``\'') as an escape
     character within strings. With this mode enabled, backslash
     becomes an ordinary character like any other. (Implemented in MySQL
     5.0.1)

   *  `NO_DIR_IN_CREATE'

     When creating a table, ignore all `INDEX DIRECTORY' and `DATA
     DIRECTORY' directives. This option is useful on slave replication
     servers.

   *  `NO_ENGINE_SUBSTITUTION'

     Control automatic substitution of the default storage engine when
     a statement such as *Note `CREATE TABLE': create-table. or *Note
     `ALTER TABLE': alter-table.  specifies a storage engine that is
     disabled or not compiled in. (Implemented in MySQL 5.0.8)

     With `NO_ENGINE_SUBSTITUTION' disabled, the default engine is used
     and a warning occurs if the desired engine is known but disabled
     or not compiled in.  If the desired engine is invalid (not a known
     engine name), an error occurs and the table is not created or
     altered.

     With `NO_ENGINE_SUBSTITUTION' enabled, an error occurs and the
     table is not created or altered if the desired engine is
     unavailable for any reason (whether disabled or invalid).

   *  `NO_FIELD_OPTIONS'

     Do not print MySQL-specific column options in the output of *Note
     `SHOW CREATE TABLE': show-create-table. This mode is used by *Note
     `mysqldump': mysqldump. in portability mode.

   *  `NO_KEY_OPTIONS'

     Do not print MySQL-specific index options in the output of *Note
     `SHOW CREATE TABLE': show-create-table. This mode is used by *Note
     `mysqldump': mysqldump. in portability mode.

   *  `NO_TABLE_OPTIONS'

     Do not print MySQL-specific table options (such as `ENGINE') in
     the output of *Note `SHOW CREATE TABLE': show-create-table. This
     mode is used by *Note `mysqldump': mysqldump. in portability mode.

   *  `NO_UNSIGNED_SUBTRACTION'

     By default, subtraction between integer operands produces an
     `UNSIGNED' result if any operand is`UNSIGNED'. When
     `NO_UNSIGNED_SUBTRACTION' is enabled, the subtraction result is
     signed, _even if any operand is unsigned_. For example, compare the
     type of column `c2' in table `t1' with that of column `c2' in
     table `t2':

          mysql> SET sql_mode='';
          mysql> CREATE TABLE test (c1 BIGINT UNSIGNED NOT NULL);
          mysql> CREATE TABLE t1 SELECT c1 - 1 AS c2 FROM test;
          mysql> DESCRIBE t1;
          +-------+---------------------+------+-----+---------+-------+
          | Field | Type                | Null | Key | Default | Extra |
          +-------+---------------------+------+-----+---------+-------+
          | c2    | bigint(21) unsigned |      |     | 0       |       |
          +-------+---------------------+------+-----+---------+-------+

          mysql> SET sql_mode='NO_UNSIGNED_SUBTRACTION';
          mysql> CREATE TABLE t2 SELECT c1 - 1 AS c2 FROM test;
          mysql> DESCRIBE t2;
          +-------+------------+------+-----+---------+-------+
          | Field | Type       | Null | Key | Default | Extra |
          +-------+------------+------+-----+---------+-------+
          | c2    | bigint(21) |      |     | 0       |       |
          +-------+------------+------+-----+---------+-------+

     Note that this means that `BIGINT UNSIGNED' is not 100% usable in
     all contexts. See *Note cast-functions::.

          mysql> SET sql_mode = '';
          mysql> SELECT CAST(0 AS UNSIGNED) - 1;
          +-------------------------+
          | CAST(0 AS UNSIGNED) - 1 |
          +-------------------------+
          |    18446744073709551615 |
          +-------------------------+

          mysql> SET sql_mode = 'NO_UNSIGNED_SUBTRACTION';
          mysql> SELECT CAST(0 AS UNSIGNED) - 1;
          +-------------------------+
          | CAST(0 AS UNSIGNED) - 1 |
          +-------------------------+
          |                      -1 |
          +-------------------------+

   *  `NO_ZERO_DATE'

     In strict mode, do not permit `'0000-00-00'' as a valid date. You
     can still insert zero dates with the `IGNORE' option. When not in
     strict mode, the date is accepted but a warning is generated.
     (Added in MySQL 5.0.2)

   *  `NO_ZERO_IN_DATE'

     In strict mode, do not accept dates where the year part is nonzero
     but the month or day part is 0 (for example, `'0000-00-00'' is
     legal but `'2010-00-01'' and `'2010-01-00'' are not). If used with
     the `IGNORE' option, MySQL inserts a `'0000-00-00'' date for any
     such date. When not in strict mode, the date is accepted but a
     warning is generated. (Added in MySQL 5.0.2)

   *  `ONLY_FULL_GROUP_BY'

     Do not permit queries for which the select list refers to
     nonaggregated columns that are not named in the `GROUP BY' clause.
     The following query is invalid with this mode enabled because
     `address' is not named in the `GROUP BY' clause:

          SELECT name, address, MAX(age) FROM t GROUP BY name;

     As of MySQL 5.0.23, this mode also restricts references to
     nonaggregated columns in the `HAVING' clause that are not named in
     the `GROUP BY' clause.

   *  `PIPES_AS_CONCAT'

     Treat `||' as a string concatenation operator (same as `CONCAT()')
     rather than as a synonym for `OR'.

   *  `REAL_AS_FLOAT'

     Treat *Note `REAL': numeric-types. as a synonym for *Note `FLOAT':
     numeric-types. By default, MySQL treats *Note `REAL':
     numeric-types. as a synonym for *Note `DOUBLE': numeric-types.

   *  `STRICT_ALL_TABLES'

     Enable strict mode for all storage engines. Invalid data values
     are rejected. Additional detail follows. (Added in MySQL 5.0.2)

   *  `STRICT_TRANS_TABLES'

     Enable strict mode for transactional storage engines, and when
     possible for nontransactional storage engines. Additional details
     follow. (Implemented in MySQL 5.0.2)

Strict mode controls how MySQL handles input values that are invalid or
missing. A value can be invalid for several reasons.  For example, it
might have the wrong data type for the column, or it might be out of
range. A value is missing when a new row to be inserted does not
contain a value for a non-`NULL' column that has no explicit `DEFAULT'
clause in its definition. (For a `NULL' column, `NULL' is inserted if
the value is missing.)

For transactional tables, an error occurs for invalid or missing values
in a statement when either of the `STRICT_ALL_TABLES' or
`STRICT_TRANS_TABLES' modes are enabled. The statement is aborted and
rolled back.

For nontransactional tables, the behavior is the same for either mode,
if the bad value occurs in the first row to be inserted or updated. The
statement is aborted and the table remains unchanged.  If the statement
inserts or modifies multiple rows and the bad value occurs in the
second or later row, the result depends on which strict option is
enabled:

   * For `STRICT_ALL_TABLES', MySQL returns an error and ignores the
     rest of the rows. However, in this case, the earlier rows still
     have been inserted or updated. This means that you might get a
     partial update, which might not be what you want. To avoid this,
     it is best to use single-row statements because these can be
     aborted without changing the table.

   * For `STRICT_TRANS_TABLES', MySQL converts an invalid value to the
     closest valid value for the column and insert the adjusted value.
     If a value is missing, MySQL inserts the implicit default value
     for the column data type. In either case, MySQL generates a warning
     rather than an error and continues processing the statement.
     Implicit defaults are described in *Note data-type-defaults::.

Strict mode disallows invalid date values such as `'2004-04-31''. It
does not disallow dates with zero month or day parts such as
`'2004-04-00'' or `zero' dates. To disallow these as well, enable the
`NO_ZERO_IN_DATE' and `NO_ZERO_DATE' SQL modes in addition to strict
mode.

If you are not using strict mode (that is, neither
`STRICT_TRANS_TABLES' nor `STRICT_ALL_TABLES' is enabled), MySQL
inserts adjusted values for invalid or missing values and produces
warnings. In strict mode, you can produce this behavior by using *Note
`INSERT IGNORE': insert. or `UPDATE IGNORE'. See *Note show-warnings::.

Strict mode does not affect whether foreign key constraints are
checked. `foreign_key_checks' can be used for that. (See *Note
server-system-variables::.)

The following special modes are provided as shorthand for combinations
of mode values from the preceding list. All are available in MySQL 5.0
beginning with version 5.0.0, except for `TRADITIONAL', which was
implemented in MySQL 5.0.2.

The descriptions include all mode values that are available in the most
recent version of MySQL. For older versions, a combination mode does
not include individual mode values that are not available except in
newer versions.

   *  `ANSI'

     Equivalent to `REAL_AS_FLOAT', `PIPES_AS_CONCAT', `ANSI_QUOTES',
     `IGNORE_SPACE'. Before MySQL 5.0.3, `ANSI' also includes
     `ONLY_FULL_GROUP_BY'.

     As of MySQL 5.0.40, `ANSI' mode also causes the server to return
     an error for queries where a set function S with an outer reference
     `S(OUTER_REF)' cannot be aggregated in the outer query against
     which the outer reference has been resolved. This is such a query:

          SELECT * FROM t1 WHERE t1.a IN (SELECT MAX(t1.b) FROM t2 WHERE ...);

     Here, `MAX(t1.b)' cannot aggregated in the outer query because it
     appears in the `WHERE' clause of that query. Standard SQL requires
     an error in this situation. If `ANSI' mode is not enabled, the
     server treats `S(OUTER_REF)' in such queries the same way that it
     would interpret `S(CONST)', as was always done prior to 5.0.40.

     See *Note ansi-mode::.

   *  `DB2'

     Equivalent to `PIPES_AS_CONCAT', `ANSI_QUOTES', `IGNORE_SPACE',
     `NO_KEY_OPTIONS', `NO_TABLE_OPTIONS', `NO_FIELD_OPTIONS'.

   *  `MAXDB'

     Equivalent to `PIPES_AS_CONCAT', `ANSI_QUOTES', `IGNORE_SPACE',
     `NO_KEY_OPTIONS', `NO_TABLE_OPTIONS', `NO_FIELD_OPTIONS',
     `NO_AUTO_CREATE_USER'.

   *  `MSSQL'

     Equivalent to `PIPES_AS_CONCAT', `ANSI_QUOTES', `IGNORE_SPACE',
     `NO_KEY_OPTIONS', `NO_TABLE_OPTIONS', `NO_FIELD_OPTIONS'.

   *  `MYSQL323'

     Equivalent to `NO_FIELD_OPTIONS', `HIGH_NOT_PRECEDENCE'.

   *  `MYSQL40'

     Equivalent to `NO_FIELD_OPTIONS', `HIGH_NOT_PRECEDENCE'.

   *  `ORACLE'

     Equivalent to `PIPES_AS_CONCAT', `ANSI_QUOTES', `IGNORE_SPACE',
     `NO_KEY_OPTIONS', `NO_TABLE_OPTIONS', `NO_FIELD_OPTIONS',
     `NO_AUTO_CREATE_USER'.

   *  `POSTGRESQL'

     Equivalent to `PIPES_AS_CONCAT', `ANSI_QUOTES', `IGNORE_SPACE',
     `NO_KEY_OPTIONS', `NO_TABLE_OPTIONS', `NO_FIELD_OPTIONS'.

   *  `TRADITIONAL'

     Equivalent to `STRICT_TRANS_TABLES', `STRICT_ALL_TABLES',
     `NO_ZERO_IN_DATE', `NO_ZERO_DATE', `ERROR_FOR_DIVISION_BY_ZERO',
     `NO_AUTO_CREATE_USER'.


File: manual.info,  Node: server-side-help-support,  Next: server-signal-response,  Prev: server-sql-mode,  Up: mysqld-server

6.1.7 Server-Side Help
----------------------

MySQL Server supports a *Note `HELP': help.  statement that returns
online information from the MySQL Reference manual (see *Note help::).
The proper operation of this statement requires that the help tables in
the `mysql' database be initialized with help topic information, which
is done by processing the contents of the `fill_help_tables.sql' script.

If you install MySQL using a binary or source distribution on Unix,
help table setup occurs when you run *Note `mysql_install_db':
mysql-install-db. For an RPM distribution on Linux or binary
distribution on Windows, help table setup occurs as part of the MySQL
installation process.

If you upgrade MySQL using a binary distribution, the help tables are
not upgraded automatically, but you can upgrade them manually.  Locate
the `fill_help_tables.sql' file in the `share' or `share/mysql'
directory. Change location into that directory and process the file
with the *Note `mysql': mysql. client as follows:

     shell> mysql -u root mysql < fill_help_tables.sql

You can also obtain the latest `fill_help_tables.sql' at any time to
upgrade your help tables. Download the proper file for your version of
MySQL from `http://dev.mysql.com/doc/index-other.html'. After
downloading and uncompressing the file, process it with *Note `mysql':
mysql. as described previously.

If you are working with Bazaar and a MySQL development source tree, you
will need to download the `fill_help_tables.sql' file because the tree
contains only a `stub' version.


File: manual.info,  Node: server-signal-response,  Next: server-shutdown,  Prev: server-side-help-support,  Up: mysqld-server

6.1.8 Server Response to Signals
--------------------------------

On Unix, signals can be sent to processes.  *Note `mysqld': mysqld.
responds to signals sent to it as follows:

   * `SIGTERM' causes the server to shut down.

   * `SIGHUP' causes the server to reload the grant tables and flush
     the logs (like *Note `FLUSH PRIVILEGES': flush. and *Note `FLUSH
     LOGS': flush.).  It also writes a status report to the error log
     that has this format:

          Status information:

          Current dir: /var/mysql/data/
          Running threads: 0  Stack size: 196608
          Current locks:

          Key caches:
          default
          Buffer_size:       8388600
          Block_size:           1024
          Division_limit:        100
          Age_limit:             300
          blocks used:             0
          not flushed:             0
          w_requests:              0
          writes:                  0
          r_requests:              0
          reads:                   0

          handler status:
          read_key:            0
          read_next:           0
          read_rnd             0
          read_first:          1
          write:               0
          delete               0
          update:              0

          Table status:
          Opened tables:          5
          Open tables:            0
          Open files:             7
          Open streams:           0

          Alarm status:
          Active alarms:   1
          Max used alarms: 2
          Next alarm time: 67

On some Mac OS X 10.3 versions, *Note `mysqld': mysqld. ignores
`SIGHUP' and `SIGQUIT'.


File: manual.info,  Node: server-shutdown,  Prev: server-signal-response,  Up: mysqld-server

6.1.9 The Shutdown Process
--------------------------

The server shutdown process takes place as follows:

  1. The shutdown process is initiated.

     This can occur initiated several ways. For example, a user with
     the `SHUTDOWN' privilege can execute a *Note `mysqladmin
     shutdown': mysqladmin. command.  *Note `mysqladmin': mysqladmin.
     can be used on any platform supported by MySQL. Other operating
     system-specific shutdown initiation methods are possible as well:
     The server shuts down on Unix when it receives a `SIGTERM' signal.
     A server running as a service on Windows shuts down when the
     services manager tells it to.

  2. The server creates a shutdown thread if necessary.

     Depending on how shutdown was initiated, the server might create a
     thread to handle the shutdown process. If shutdown was requested
     by a client, a shutdown thread is created. If shutdown is the
     result of receiving a `SIGTERM' signal, the signal thread might
     handle shutdown itself, or it might create a separate thread to do
     so. If the server tries to create a shutdown thread and cannot
     (for example, if memory is exhausted), it issues a diagnostic
     message that appears in the error log:

          Error: Can't create thread to kill server

  3. The server stops accepting new connections.

     To prevent new activity from being initiated during shutdown, the
     server stops accepting new client connections by closing the
     handlers for the network interfaces to which it normally listens
     for connections: the TCP/IP port, the Unix socket file, the
     Windows named pipe, and shared memory on Windows.

  4. The server terminates current activity.

     For each thread associated with a client connection, the server
     breaks the connection to the client and marks the thread as
     killed. Threads die when they notice that they are so marked.
     Threads for idle connections die quickly. Threads that currently
     are processing statements check their state periodically and take
     longer to die. For additional information about thread
     termination, see *Note kill::, in particular for the instructions
     about killed *Note `REPAIR TABLE': repair-table. or *Note
     `OPTIMIZE TABLE': optimize-table. operations on `MyISAM' tables.

     For threads that have an open transaction, the transaction is
     rolled back. Note that if a thread is updating a nontransactional
     table, an operation such as a multiple-row *Note `UPDATE': update.
     or *Note `INSERT': insert. may leave the table partially updated
     because the operation can terminate before completion.

     If the server is a master replication server, it treats threads
     associated with currently connected slaves like other client
     threads. That is, each one is marked as killed and exits when it
     next checks its state.

     If the server is a slave replication server, it stops the the I/O
     and SQL threads, if they are active, before marking client threads
     as killed. The SQL thread is permitted to finish its current
     statement (to avoid causing replication problems), and then stops.
     If the SQL thread was in the middle of a transaction at this
     point, the transaction is rolled back.

     If the slave is updating a non-transactional table when it is
     forcibly killed, the slave's data may become inconsistent with the
     master.

  5. The server shuts down or closes storage engines.

     At this stage, the server flushes the table cache and closes all
     open tables.

     Each storage engine performs any actions necessary for tables that
     it manages. For example, `MyISAM' flushes any pending index writes
     for a table.  `InnoDB' flushes its buffer pool to disk (starting
     from 5.0.5: unless `innodb_fast_shutdown' is 2), writes the
     current LSN to the tablespace, and terminates its own internal
     threads.

  6. The server exits.


File: manual.info,  Node: server-logs,  Next: security,  Prev: mysqld-server,  Up: server-administration

6.2 MySQL Server Logs
=====================

* Menu:

* error-log::                    The Error Log
* query-log::                    The General Query Log
* binary-log::                   The Binary Log
* slow-query-log::               The Slow Query Log
* log-file-maintenance::         Server Log Maintenance

MySQL Server has several logs that can help you find out what activity
is taking place.

Log Type               Information Written to Log
Error log              Problems encountered starting, running, or
                       stopping *Note `mysqld': mysqld.
General query log      Established client connections and statements
                       received from clients
Binary log             Statements that change data (also used for
                       replication)
Relay log              Data changes received from a replication master
                       server
Slow query log         All queries that took more than `long_query_time'
                       seconds to execute or did not use indexes

By default, no logs are enabled. The following log-specific sections
provide information about the server options that enable logging.

By default, the server writes files for all enabled logs in the data
directory. You can force the server to close and reopen the log files
(or in some cases switch to a new log file) by flushing the logs. Log
flushing occurs when you issue a *Note `FLUSH LOGS': flush.  statement;
execute *Note `mysqladmin': mysqladmin. with a `flush-logs' or `refresh'
argument; or execute *Note `mysqldump': mysqldump. with a
`--flush-logs' or `--master-data' option. See *Note flush::, *Note
mysqladmin::, and *Note mysqldump::. In addition, the binary log is
flushed when its size reaches the value of the `max_binlog_size' system
variable.

The relay log is used only on slave replication servers, to hold data
changes from the master server that must also be made on the slave. For
discussion of relay log contents and configuration, see *Note
slave-logs-relaylog::.

For information about log maintenance operations such as expiration of
old log files, see *Note log-file-maintenance::.

See *Note password-security-admin::, for information about keeping logs
secure.


File: manual.info,  Node: error-log,  Next: query-log,  Prev: server-logs,  Up: server-logs

6.2.1 The Error Log
-------------------

The error log contains information indicating when *Note `mysqld':
mysqld. was started and stopped and also any critical errors that occur
while the server is running. If *Note `mysqld': mysqld. notices a table
that needs to be automatically checked or repaired, it writes a message
to the error log.

On some operating systems, the error log contains a stack trace if
*Note `mysqld': mysqld. dies. The trace can be used to determine where
*Note `mysqld': mysqld. died. See MySQL Internals: Porting
(http://forge.mysql.com/wiki/MySQL_Internals_Porting).

You can specify where *Note `mysqld': mysqld. writes the error log with
the `--log-error[=FILE_NAME]' option. If the option is given with no
FILE_NAME value, *Note `mysqld': mysqld. uses the name `HOST_NAME.err'
by default. The server creates the file in the data directory unless an
absolute path name is given to specify a different directory.

If you do not specify `--log-error', or (on Windows) if you use the
`--console' option, errors are written to `stderr', the standard error
output.  Usually this is your terminal.

On Windows, error output is always written to the error log if
`--console' is not given.

In addition, on Windows, events and error messages are written to the
Windows Event Log within the Application log. Entries marked as
`Warning' and `Note' are written to the Event Log, but informational
messages (such as information statements from individual storage
engines) are not copied to the Event Log. The log entries have a source
of `MySQL'. You cannot disable writing information to the Windows Event
Log.

If you flush the logs using *Note `FLUSH LOGS': flush. or *Note
`mysqladmin flush-logs': mysqladmin. and *Note `mysqld': mysqld. is
writing the error log to a file (for example, if it was started with the
`--log-error' option), it renames the current log file with the suffix
`-old', then creates a new empty log file. Be aware that a second
log-flushing operation thus causes the original error log file to be
lost unless you save it under a different name. For example, you can
use the following commands to save the file:

     shell> mysqladmin flush-logs
     shell> mv HOST_NAME.err-old BACKUP-DIRECTORY

No error log renaming occurs when the logs are flushed if the server is
not writing to a named file.

If you use *Note `mysqld_safe': mysqld-safe. to start *Note `mysqld':
mysqld, *Note `mysqld_safe': mysqld-safe. arranges for *Note `mysqld':
mysqld. to write error messages to a log file. If you specify a file
name using `--log-error' to *Note `mysqld_safe': mysqld-safe. or *Note
`mysqld': mysqld, that file name is used. Otherwise, *Note
`mysqld_safe': mysqld-safe. uses the default error log file.

If *Note `mysqld_safe': mysqld-safe. is used to start *Note `mysqld':
mysqld. and *Note `mysqld': mysqld. dies unexpectedly, *Note
`mysqld_safe': mysqld-safe. notices that it needs to restart *Note
`mysqld': mysqld. and writes a `restarted mysqld' message to the error
log.

The `--log-warnings' option or `log_warnings' system variable can be
used to control warning logging to the error log. The default value is
enabled (1). Warning logging can be disabled using a value of 0. If the
value is greater than 1, aborted connections are written to the error
log. See *Note communication-errors::.


File: manual.info,  Node: query-log,  Next: binary-log,  Prev: error-log,  Up: server-logs

6.2.2 The General Query Log
---------------------------

The general query log is a general record of what *Note `mysqld':
mysqld. is doing. The server writes information to this log when
clients connect or disconnect, and it logs each SQL statement received
from clients. The general query log can be very useful when you suspect
an error in a client and want to know exactly what the client sent to
*Note `mysqld': mysqld.

*Note `mysqld': mysqld. writes statements to the query log in the order
that it receives them, which might differ from the order in which they
are executed. This logging order contrasts to the binary log, for which
statements are written after they are executed but before any locks are
released. (Also, the query log contains all statements, whereas the
binary log does not contain statements that only select data.)

To enable the general query log, start *Note `mysqld': mysqld.  with the
`--log[=FILE_NAME]' or `-l [FILE_NAME]' option.

If no FILE_NAME value is given for `--log' or `-l', the default name is
`HOST_NAME.log'. The server creates the file in the data directory
unless an absolute path name is given to specify a different directory.

Server restarts and log flushing do not cause a new general query log
file to be generated (although flushing closes and reopens it). On
Unix, you can rename the file and create a new one by using the
following commands:

     shell> mv HOST_NAME.log HOST_NAME-old.log
     shell> mysqladmin flush-logs
     shell> mv HOST_NAME-old.log BACKUP-DIRECTORY

On Windows, you cannot rename a log file while the server has it open
before MySQL 5.0.17. You must stop the server, rename the file, and
then restart the server to create a new log file. As of 5.0.17, this
applies only to the error log. However, a stop and restart can be
avoided by using *Note `FLUSH LOGS': flush, which causes the server to
rename the error log with an `-old' suffix and open a new error log.

The general query log should be protected because logged statements
might contain passwords. See *Note password-security-admin::.


File: manual.info,  Node: binary-log,  Next: slow-query-log,  Prev: query-log,  Up: server-logs

6.2.3 The Binary Log
--------------------

The binary log contains `events' that describe database changes such as
table creation operations or changes to table data. It also contains
events for statements that potentially could have made changes (for
example, a *Note `DELETE': delete. which matched no rows). The binary
log also contains information about how long each statement took that
updated data. The binary log has two important purposes:

   * For replication, the binary log is used on master replication
     servers as a record of the statements to be sent to slave servers.
     The master server sends the events contained in its binary log to
     its slaves, which execute those events to make the same data
     changes that were made on the master. See *Note
     replication-implementation::.

   * Certain data recovery operations require use of the binary log.
     After a backup has been restored, the events in the binary log
     that were recorded after the backup was made are re-executed.
     These events bring databases up to date from the point of the
     backup. See *Note point-in-time-recovery::.

*Note*:

The binary log has replaced the old update log, which is no longer
available as of MySQL 5.0. The binary log contains all information that
is available in the update log in a more efficient format and in a
manner that is transaction-safe. If you are using transactions, you
must use the MySQL binary log for backups instead of the old update log.

Running a server with binary logging enabled makes performance slightly
slower. However, the benefits of the binary log in enabling you to set
up replication and for restore operations generally outweigh this minor
performance decrement.

For information about server options and variables affecting the
operation of binary logging, see *Note replication-options-binary-log::.

The binary log is not used for statements such as *Note `SELECT':
select. or *Note `SHOW': show. that do not modify data. If you want to
log all statements (for example, to identify a problem query), use the
general query log. See *Note query-log::.

The binary log should be protected because logged statements might
contain passwords. See *Note password-security-admin::.

For information about the format of the binary log, see
`http://forge.mysql.com/wiki/MySQL_Internals_Binary_Log'.

To enable the binary log, start the server with the
`--log-bin[=BASE_NAME]' option. If no BASE_NAME value is given, the
default name is the value of the `pid-file' option (which by default is
the name of host machine) followed by `-bin'. If the basename is given,
the server writes the file in the data directory unless the basename is
given with a leading absolute path name to specify a different
directory. It is recommended that you specify a basename; see *Note
bugs::, for the reason.

*Note*:

From MySQL 5.0.41 through 5.0.52, `mysql' was used when no BASE_NAME
was specified. Also in these versions, a path given as part of the
`--log-bin' options was treated as absolute rather than relative. The
previous behaviors were restored in MySQL 5.0.54. (See Bug #28603 and
Bug #28597.)

If you supply an extension in the log name (for example,
`--log-bin=BASE_NAME.EXTENSION'), the extension is silently removed and
ignored.

*Note `mysqld': mysqld. appends a numeric extension to the binary log
basename to generate binary log file names. The number increases each
time the server creates a new log file, thus creating an ordered series
of files. The server creates a new file in the series each time it
starts or flushes the logs. The server also creates a new binary log
file automatically after the current log's size reaches
`max_binlog_size'. A binary log file may become larger than
`max_binlog_size' if you are using large transactions because a
transaction is written to the file in one piece, never split between
files.

To keep track of which binary log files have been used, *Note `mysqld':
mysqld. also creates a binary log index file that contains the names of
all used binary log files. By default, this has the same basename as
the binary log file, with the extension `'.index''. You can change the
name of the binary log index file with the `--log-bin-index[=FILE_NAME]'
option. You should not manually edit this file while *Note `mysqld':
mysqld. is running; doing so would confuse *Note `mysqld': mysqld.

The term `binary log file' generally denotes an individual numbered
file containing database events. The term `binary log' collectively
denotes the set of numbered binary log files plus the index file.

The server evaluates the `--binlog-do-db' and `--binlog-ignore-db'
options in the same way as it does the `--replicate-do-db' and
`--replicate-ignore-db' options. For information about how this is
done, see *Note replication-rules-db-options::.

A replication slave server by default does not write to its own binary
log any data modifications that are received from the replication
master. To log these modifications, start the slave with the
`--log-slave-updates' option in addition to the `--log-bin' option (see
*Note replication-options-slave::). This is done when a slave is also
to act as a master to other slaves in chained replication.

You can delete all binary log files with the *Note `RESET MASTER':
reset-master. statement, or a subset of them with *Note `PURGE BINARY
LOGS': purge-binary-logs. See *Note reset::, and *Note
purge-binary-logs::.

If you are using replication, you should not delete old binary log
files on the master until you are sure that no slave still needs to use
them. For example, if your slaves never run more than three days
behind, once a day you can execute *Note `mysqladmin flush-logs':
mysqladmin. on the master and then remove any logs that are more than
three days old. You can remove the files manually, but it is preferable
to use *Note `PURGE BINARY LOGS': purge-binary-logs, which also safely
updates the binary log index file for you (and which can take a date
argument). See *Note purge-binary-logs::.

A client that has the `SUPER' privilege can disable binary logging of
its own statements by using a `SET sql_log_bin=0' statement. See *Note
server-system-variables::.

You can display the contents of binary log files with the *Note
`mysqlbinlog': mysqlbinlog. utility. This can be useful when you want
to reprocess statements in the log for a recovery operation. For
example, you can update a MySQL server from the binary log as follows:

     shell> mysqlbinlog LOG_FILE | mysql -h SERVER_NAME

*Note `mysqlbinlog': mysqlbinlog. also can be used to display
replication slave relay log file contents because they are written
using the same format as binary log files. For more information on the
*Note `mysqlbinlog': mysqlbinlog. utility and how to use it, see *Note
mysqlbinlog::. For more information about the binary log and recovery
operations, see *Note point-in-time-recovery::.

Binary logging is done immediately after a statement completes but
before any locks are released or any commit is done. This ensures that
the log is logged in execution order.

Updates to nontransactional tables are stored in the binary log
immediately after execution. In MySQL 5.0.53 and earlier versions of
MySQL 5.0, an *Note `UPDATE': update. statement using a stored function
that modified a nontransactional table was not logged if it failed, and
an *Note `INSERT ... ON DUPLICATE KEY UPDATE': insert-on-duplicate.
statement that encountered a duplicate key constraint--but did not
actually change any data--was not logged. Beginning with MySQL 5.0.54,
both of these statements are written to the binary log. (Bug #23333)

Within an uncommitted transaction, all updates (*Note `UPDATE': update,
*Note `DELETE': delete, or *Note `INSERT': insert.) that change
transactional tables such as `BDB' or `InnoDB' tables are cached until
a *Note `COMMIT': commit.  statement is received by the server. At that
point, *Note `mysqld': mysqld. writes the entire transaction to the
binary log before the *Note `COMMIT': commit. is executed.

Modifications to nontransactional tables cannot be rolled back. If a
transaction that is rolled back includes modifications to
nontransactional tables, the entire transaction is logged with a *Note
`ROLLBACK': commit.  statement at the end to ensure that the
modifications to those tables are replicated.

When a thread that handles the transaction starts, it allocates a
buffer of `binlog_cache_size' to buffer statements. If a statement is
bigger than this, the thread opens a temporary file to store the
transaction. The temporary file is deleted when the thread ends.

The `Binlog_cache_use' status variable shows the number of transactions
that used this buffer (and possibly a temporary file) for storing
statements. The `Binlog_cache_disk_use' status variable shows how many
of those transactions actually had to use a temporary file. These two
variables can be used for tuning `binlog_cache_size' to a large enough
value that avoids the use of temporary files.

The `max_binlog_cache_size' system variable (default 4GB, which is also
the maximum) can be used to restrict the total size used to cache a
multiple-statement transaction. If a transaction is larger than this
many bytes, it fails and rolls back. The minimum value is 4096.

If you are using the binary log and row based logging, concurrent
inserts are converted to normal inserts for `CREATE ...  SELECT' or
*Note `INSERT ... SELECT': insert-select. statement. This is done to
ensure that you can re-create an exact copy of your tables by applying
the log during a backup operation. If you are using statement-based
logging, the original statement is written to the log.

The binary log format has some known limitations that can affect
recovery from backups. See *Note replication-features::.

Binary logging for stored programs is done as described in *Note
stored-programs-logging::.

Note that the binary log format differs in MySQL 5.0 from previous
versions of MySQL, due to enhancements in replication. See *Note
replication-compatibility::.

Writes to the binary log file and binary log index file are handled in
the same way as writes to `MyISAM' tables. See *Note full-disk::.

By default, the binary log is not synchronized to disk at each write.
So if the operating system or machine (not only the MySQL server)
crashes, there is a chance that the last statements of the binary log
are lost. To prevent this, you can make the binary log be synchronized
to disk after every N writes to the binary log, with the `sync_binlog'
system variable. See *Note server-system-variables::. 1 is the safest
value for `sync_binlog', but also the slowest. Even with `sync_binlog'
set to 1, there is still the chance of an inconsistency between the
table content and binary log content in case of a crash. For example,
if you are using `InnoDB' tables and the MySQL server processes a *Note
`COMMIT': commit.  statement, it writes the whole transaction to the
binary log and then commits this transaction into `InnoDB'. If the
server crashes between those two operations, the transaction is rolled
back by `InnoDB' at restart but still exists in the binary log. This
problem can be solved with the `--innodb-safe-binlog' option, which
adds consistency between the content of `InnoDB' tables and the binary
log. (Note: `--innodb-safe-binlog' is unneeded as of MySQL 5.0; it was
made obsolete by the introduction of XA transaction support.)

For this option to provide a greater degree of safety, the MySQL server
should also be configured to synchronize the binary log and the
`InnoDB' logs to disk at every transaction.  The `InnoDB' logs are
synchronized by default, and `sync_binlog=1' can be used to synchronize
the binary log. The effect of this option is that at restart after a
crash, after doing a rollback of transactions, the MySQL server cuts
rolled back `InnoDB' transactions from the binary log. This ensures
that the binary log reflects the exact data of `InnoDB' tables, and so,
that the slave remains in synchrony with the master (not receiving a
statement which has been rolled back).

Note that `--innodb-safe-binlog' can be used even if the MySQL server
updates other storage engines than `InnoDB'. Only statements and
transactions that affect `InnoDB' tables are subject to removal from
the binary log at `InnoDB''s crash recovery. If the MySQL server
discovers at crash recovery that the binary log is shorter than it
should have been, it lacks at least one successfully committed `InnoDB'
transaction.  This should not happen if `sync_binlog=1' and the
disk/file system do an actual sync when they are requested to (some do
not), so the server prints an error message `The binary log `file_name'
is shorter than its expected size'. In this case, this binary log is not
correct and replication should be restarted from a fresh snapshot of
the master's data.

For MySQL 5.0.46, the session values of the following system variables
are written to the binary log and honored by the replication slave when
parsing the binary log:

   * `sql_mode'

   * `foreign_key_checks'

   * `unique_checks'

   * `character_set_client'

   * `collation_connection'

   * `collation_database'

   * `collation_server'

   * `sql_auto_is_null'


File: manual.info,  Node: slow-query-log,  Next: log-file-maintenance,  Prev: binary-log,  Up: server-logs

6.2.4 The Slow Query Log
------------------------

The slow query log consists of SQL statements that took more than
`long_query_time' seconds to execute. The minimum and default values of
`long_query_time' are 1 and 10, respectively.

The time to acquire the initial table locks is not counted as execution
time. *Note `mysqld': mysqld. writes a statement to the slow query log
after it has been executed and after all locks have been released, so
log order might differ from execution order.

To enable the slow query log, start *Note `mysqld': mysqld. with the
`--log-slow-queries[=FILE_NAME]' option.

If no FILE_NAME value is given for `--log-slow-queries', the default
name is `HOST_NAME-slow.log'.  The server creates the file in the data
directory unless an absolute path name is given to specify a different
directory.

To include queries that do not use indexes in the statements written to
the slow query log, use the `--log-queries-not-using-indexes' server
option. See *Note server-options::.

To include slow administrative statements such as *Note `OPTIMIZE
TABLE': optimize-table, *Note `ANALYZE TABLE': analyze-table, and *Note
`ALTER TABLE': alter-table. in the statements written to the slow query
log, use the `--log-slow-admin-statements' server option.

The server does not write queries handled by the query cache to the
slow query log, nor queries that would not benefit from the presence of
an index because the table has zero rows or one row.

Replication slaves do not write replicated queries to the slow query
log, even if the same queries were written to the slow query log on the
master. This is a known issue. (Bug #23300)

The slow query log should be protected because logged statements might
contain passwords. See *Note password-security-admin::.

The slow query log can be used to find queries that take a long time to
execute and are therefore candidates for optimization.  However,
examining a long slow query log can become a difficult task. To make
this easier, you can process a slow query log file using the *Note
`mysqldumpslow': mysqldumpslow. command to summarize the queries that
appear in the log. See *Note mysqldumpslow::.


File: manual.info,  Node: log-file-maintenance,  Prev: slow-query-log,  Up: server-logs

6.2.5 Server Log Maintenance
----------------------------

MySQL Server can create a number of different log files to help you see
what activity is taking place. See *Note server-logs::. However, you
must clean up these files regularly to ensure that the logs do not take
up too much disk space.

When using MySQL with logging enabled, you may want to back up and
remove old log files from time to time and tell MySQL to start logging
to new files. See *Note backup-methods::.

On a Linux (Red Hat) installation, you can use the `mysql-log-rotate'
script for this. If you installed MySQL from an RPM distribution, this
script should have been installed automatically. You should be careful
with this script if you are using the binary log for replication. You
should not remove binary logs until you are certain that their contents
have been processed by all slaves.

On other systems, you must install a short script yourself that you
start from `cron' (or its equivalent) for handling log files.

For the binary log, you can set the `expire_logs_days' system variable
to expire binary log files automatically after a given number of days
(see *Note server-system-variables::). If you are using replication,
you should set the variable no lower than the maximum number of days
your slaves might lag behind the master. To remove binary logs on
demand, use the *Note `PURGE BINARY LOGS': purge-binary-logs. statement
(see *Note purge-binary-logs::).

You can force MySQL to start using new log files by flushing the logs.
Log flushing occurs when you issue a *Note `FLUSH LOGS': flush.
statement or execute a *Note `mysqladmin flush-logs': mysqladmin, *Note
`mysqladmin refresh': mysqladmin, *Note `mysqldump --flush-logs':
mysqldump, or *Note `mysqldump --master-data': mysqldump. command. See
*Note flush::, *Note mysqladmin::, and *Note mysqldump::. In addition,
the binary log is flushed when its size reaches the value of the
`max_binlog_size' system variable.

A log-flushing operation does the following:

   * If general query logging (`--log') or slow query logging
     (`--log-slow-queries') to a log file is enabled, the server closes
     and reopens the general query log file or slow query log file.

   * If binary logging (`--log-bin') is used, the server closes the
     current log file and opens a new log file with the next sequence
     number.

   * If the server was started with the `--log-error' option to cause
     the error log to be written to a file, it renames the current log
     file with the suffix `-old' and creates a new empty error log file.

The server creates a new binary log file when you flush the logs.
However, it just closes and reopens the general and slow query log
files. To cause new files to be created on Unix, rename the current
logs before flushing them. At flush time, the server opens new logs
with the original names. For example, if the general and slow query
logs are named `mysql.log' and `mysql-slow.log', you can use a series of
commands like this:

     shell> cd MYSQL-DATA-DIRECTORY
     shell> mv mysql.log mysql.old
     shell> mv mysql-slow.log mysql-slow.old
     shell> mysqladmin flush-logs

On Windows, use `rename' rather than `mv'.

At this point, you can make a backup of `mysql.old' and
`mysql-slow.old' and then remove them from disk.

For older versions of MySQL, you cannot rename certain log files on
Windows while the server has them open. Before MySQL 5.0.17, this
restriction applies to all log files. You must stop the server, rename
the file, then restart the server to create a new log file. From 5.0.18
on, the restriction applies only to the error log file. To rename the
error log file, a stop and restart can be avoided by flushing the logs
to cause the server to rename the current log file with the suffix
`-old' and create a new empty error log file.

The session `sql_log_off' variable can be set to `ON' or `OFF' to
disable or enable general query logging for the current connection.


File: manual.info,  Node: security,  Next: privilege-system,  Prev: server-logs,  Up: server-administration

6.3 General Security Issues
===========================

* Menu:

* security-guidelines::          General Security Guidelines
* password-security::            Password Security in MySQL
* security-against-attack::      Making MySQL Secure Against Attackers
* privileges-options::           Security-Related `mysqld' Options
* load-data-local::              Security Issues with `LOAD DATA LOCAL'
* changing-mysql-user::          How to Run MySQL as a Normal User

This section describes some general security issues to be aware of and
what you can do to make your MySQL installation more secure against
attack or misuse. For information specifically about the access control
system that MySQL uses for setting up user accounts and checking
database access, see *Note privilege-system::.

For answers to some questions that are often asked about MySQL Server
security issues, see *Note faqs-security::.


File: manual.info,  Node: security-guidelines,  Next: password-security,  Prev: security,  Up: security

6.3.1 General Security Guidelines
---------------------------------

Anyone using MySQL on a computer connected to the Internet should read
this section to avoid the most common security mistakes.

In discussing security, we emphasize the necessity of fully protecting
the entire server host (not just the MySQL server) against all types of
applicable attacks: eavesdropping, altering, playback, and denial of
service. We do not cover all aspects of availability and fault
tolerance here.

MySQL uses security based on Access Control Lists (ACLs) for all
connections, queries, and other operations that users can attempt to
perform. There is also support for SSL-encrypted connections between
MySQL clients and servers. Many of the concepts discussed here are not
specific to MySQL at all; the same general ideas apply to almost all
applications.

When running MySQL, follow these guidelines whenever possible:

   * *Do not ever give anyone (except MySQL `root' accounts) access to
     the `user' table in the `mysql' database!* This is critical.

   * Learn the MySQL access privilege system. The *Note `GRANT': grant.
     and *Note `REVOKE': revoke. statements are used for controlling
     access to MySQL. Do not grant more privileges than necessary.
     Never grant privileges to all hosts.

     Checklist:

        * Try `mysql -u root'. If you are able to connect successfully
          to the server without being asked for a password, anyone can
          connect to your MySQL server as the MySQL `root' user with
          full privileges!  Review the MySQL installation instructions,
          paying particular attention to the information about setting a
          `root' password. See *Note default-privileges::.

        * Use the *Note `SHOW GRANTS': show-grants.  statement to check
          which accounts have access to what.  Then use the *Note
          `REVOKE': revoke.  statement to remove those privileges that
          are not necessary.

   * Do not store any plaintext passwords in your database. If your
     computer becomes compromised, the intruder can take the full list
     of passwords and use them. Instead, use `MD5()', `SHA1()', or some
     other one-way hashing function and store the hash value.

   * Do not choose passwords from dictionaries. Special programs exist
     to break passwords. Even passwords like `xfish98' are very bad.
     Much better is `duag98' which contains the same word `fish' but
     typed one key to the left on a standard QWERTY keyboard. Another
     method is to use a password that is taken from the first
     characters of each word in a sentence (for example, `Mary had a
     little lamb' results in a password of `Mhall'). The password is
     easy to remember and type, but difficult to guess for someone who
     does not know the sentence.

   * Invest in a firewall. This protects you from at least 50% of all
     types of exploits in any software. Put MySQL behind the firewall
     or in a demilitarized zone (DMZ).

     Checklist:

        * Try to scan your ports from the Internet using a tool such as
          `nmap'. MySQL uses port 3306 by default. This port should not
          be accessible from untrusted hosts. Another simple way to
          check whether or not your MySQL port is open is to try the
          following command from some remote machine, where SERVER_HOST
          is the host name or IP address of the host on which your
          MySQL server runs:

               shell> telnet SERVER_HOST 3306

          If you get a connection and some garbage characters, the port
          is open, and should be closed on your firewall or router,
          unless you really have a good reason to keep it open. If
          `telnet' hangs or the connection is refused, the port is
          blocked, which is how you want it to be.

   * Do not trust any data entered by users of your applications.  They
     can try to trick your code by entering special or escaped
     character sequences in Web forms, URLs, or whatever application
     you have built. Be sure that your application remains secure if a
     user enters something like ``; DROP DATABASE mysql;''. This is an
     extreme example, but large security leaks and data loss might
     occur as a result of hackers using similar techniques, if you do
     not prepare for them.

     A common mistake is to protect only string data values.  Remember
     to check numeric data as well. If an application generates a query
     such as `SELECT * FROM table WHERE ID=234' when a user enters the
     value `234', the user can enter the value `234 OR 1=1' to cause
     the application to generate the query `SELECT * FROM table WHERE
     ID=234 OR 1=1'. As a result, the server retrieves every row in the
     table. This exposes every row and causes excessive server load.
     The simplest way to protect from this type of attack is to use
     single quotation marks around the numeric constants: `SELECT *
     FROM table WHERE ID='234''. If the user enters extra information,
     it all becomes part of the string. In a numeric context, MySQL
     automatically converts this string to a number and strips any
     trailing nonnumeric characters from it.

     Sometimes people think that if a database contains only publicly
     available data, it need not be protected. This is incorrect. Even
     if it is permissible to display any row in the database, you
     should still protect against denial of service attacks (for
     example, those that are based on the technique in the preceding
     paragraph that causes the server to waste resources). Otherwise,
     your server becomes unresponsive to legitimate users.

     Checklist:

        * Try to enter single and double quotation marks (``''' and
          ``"'') in all of your Web forms. If you get any kind of MySQL
          error, investigate the problem right away.

        * Try to modify dynamic URLs by adding `%22' (``"''), `%23'
          (``#''), and `%27' (``''') to them.

        * Try to modify data types in dynamic URLs from numeric to
          character types using the characters shown in the previous
          examples. Your application should be safe against these and
          similar attacks.

        * Try to enter characters, spaces, and special symbols rather
          than numbers in numeric fields. Your application should
          remove them before passing them to MySQL or else generate an
          error. Passing unchecked values to MySQL is very dangerous!

        * Check the size of data before passing it to MySQL.

        * Have your application connect to the database using a user
          name different from the one you use for administrative
          purposes. Do not give your applications any access privileges
          they do not need.

   * Many application programming interfaces provide a means of
     escaping special characters in data values. Properly used, this
     prevents application users from entering values that cause the
     application to generate statements that have a different effect
     than you intend:

        * MySQL C API: Use the *Note `mysql_real_escape_string()':
          mysql-real-escape-string.  API call.

        * MySQL++: Use the `escape' and `quote' modifiers for query
          streams.

        * PHP: Use the `mysql_real_escape_string()' function (available
          as of PHP 4.3.0, prior to that PHP version use
          `mysql_escape_string()', and prior to PHP 4.0.3, use
          `addslashes()' ). Note that only `mysql_real_escape_string()'
          is character set-aware; the other functions can be `bypassed'
          when using (invalid) multi-byte character sets. In PHP 5, you
          can use the `mysqli' extension, which supports the improved
          MySQL authentication protocol and passwords, as well as
          prepared statements with placeholders.

        * Perl DBI: Use placeholders or the `quote()' method.

        * Ruby DBI: Use placeholders or the `quote()' method.

        * Java JDBC: Use a `PreparedStatement' object and placeholders.

     Other programming interfaces might have similar capabilities.

   * Do not transmit plain (unencrypted) data over the Internet.  This
     information is accessible to everyone who has the time and ability
     to intercept it and use it for their own purposes.  Instead, use
     an encrypted protocol such as SSL or SSH. MySQL supports internal
     SSL connections as of version 4.0. Another technique is to use SSH
     port-forwarding to create an encrypted (and compressed) tunnel for
     the communication.

   * Learn to use the `tcpdump' and `strings' utilities. In most cases,
     you can check whether MySQL data streams are unencrypted by
     issuing a command like the following:

          shell> tcpdump -l -i eth0 -w - src or dst port 3306 | strings

     This works under Linux and should work with small modifications
     under other systems.

     *Warning*:

     If you do not see plaintext data, this does not always mean that
     the information actually is encrypted. If you need high security,
     you should consult with a security expert.


File: manual.info,  Node: password-security,  Next: security-against-attack,  Prev: security-guidelines,  Up: security

6.3.2 Password Security in MySQL
--------------------------------

* Menu:

* password-security-admin::      Administrator Guidelines for Password Security
* password-security-user::       End-User Guidelines for Password Security
* password-hashing::             Password Hashing in MySQL
* application-password-use::     Implications of Password Hashing Changes in MySQL 4.1 for Application Programs

Passwords occur in several contexts within MySQL. The following
sections provide guidelines that enable administrators and end users to
keep these passwords secure and avoid exposing them.  There is also a
discussion of how MySQL uses password hashing internally.


File: manual.info,  Node: password-security-admin,  Next: password-security-user,  Prev: password-security,  Up: password-security

6.3.2.1 Administrator Guidelines for Password Security
......................................................

Database administrators should use the following guidelines to keep
passwords secure.

MySQL stores passwords for user accounts in the `mysql.user' table.
Access to this table should never be granted to any nonadministrative
accounts.

A user who has access to modify the plugin directory (the value of the
`plugin_dir' system variable) or the `my.cnf' file that specifies the
location of the plugin directory can replace plugins and modify the
capabilities provided by plugins.

Passwords can appear as plain text in SQL statements such as *Note
`CREATE USER': create-user, *Note `GRANT': grant, and *Note `SET
PASSWORD': set-password, or statements that invoke the `PASSWORD()'
function.  If these statements are logged by the MySQL server, the
passwords become available to anyone with access to the logs.  This
applies to the general query log, the slow query log, and the binary
log (see *Note server-logs::). To guard against unwarranted exposure to
log files, they should be located in a directory that restricts access
to only the server and the database administrator.

Replication slaves store the password for the replication master in the
`master.info' file. Access to this file should be restricted to the
database administrator.

Database backups that include tables or log files containing passwords
should be protected using a restricted access mode.


File: manual.info,  Node: password-security-user,  Next: password-hashing,  Prev: password-security-admin,  Up: password-security

6.3.2.2 End-User Guidelines for Password Security
.................................................

MySQL users should use the following guidelines to keep passwords
secure.

When you run a client program to connect to the MySQL server, it is
inadvisable to specify your password in a way that exposes it to
discovery by other users. The methods you can use to specify your
password when you run client programs are listed here, along with an
assessment of the risks of each method. In short, the safest methods
are to have the client program prompt for the password or to specify
the password in a properly protected option file.

   * Use a `-pYOUR_PASS' or `--password=YOUR_PASS' option on the
     command line. For example:

          shell> mysql -u francis -pfrank DB_NAME

     This is convenient _but insecure_, because your password becomes
     visible to system status programs such as `ps' that may be invoked
     by other users to display command lines. MySQL clients typically
     overwrite the command-line password argument with zeros during
     their initialization sequence. However, there is still a brief
     interval during which the value is visible.  Also, on some systems
     this overwriting strategy is ineffective and the password remains
     visible to `ps'. (SystemV Unix systems and perhaps others are
     subject to this problem.)

     If your operating environment is set up to display your current
     command in the title bar of your terminal window, the password
     remains visible as long as the command is running, even if the
     command has scrolled out of view in the window content area.

   * Use the `-p' or `--password' option on the command line with no
     password value specified.  In this case, the client program
     solicits the password interactively:

          shell> mysql -u francis -p DB_NAME
          Enter password: ********

     The ``*'' characters indicate where you enter your password. The
     password is not displayed as you enter it.

     It is more secure to enter your password this way than to specify
     it on the command line because it is not visible to other users.
     However, this method of entering a password is suitable only for
     programs that you run interactively. If you want to invoke a
     client from a script that runs noninteractively, there is no
     opportunity to enter the password from the keyboard. On some
     systems, you may even find that the first line of your script is
     read and interpreted (incorrectly) as your password.

   * Store your password in an option file. For example, on Unix you
     can list your password in the `[client]' section of the `.my.cnf'
     file in your home directory:

          [client]
          password=your_pass

     To keep the password safe, the file should not be accessible to
     anyone but yourself. To ensure this, set the file access mode to
     `400' or `600'.  For example:

          shell> chmod 600 .my.cnf

     To name from the command line a specific option file containing
     the password, use the `--defaults-file=FILE_NAME' option, where
     `file_name' is the full path name to the file. For example:

          shell> mysql --defaults-file=/home/francis/mysql-opts

     *Note option-files::, discusses option files in more detail.

   * Store your password in the `MYSQL_PWD' environment variable. See
     *Note environment-variables::.

     This method of specifying your MySQL password must be considered
     _extremely insecure_ and should not be used. Some versions of `ps'
     include an option to display the environment of running processes.
     If you set `MYSQL_PWD', your password is exposed to any other user
     who runs `ps'. Even on systems without such a version of `ps', it
     is unwise to assume that there are no other methods by which users
     can examine process environments.

On Unix, the *Note `mysql': mysql. client writes a record of executed
statements to a history file (see *Note mysql-history-file::). By
default, this file is named `.mysql_history' and is created in your
home directory. Passwords can appear as plain text in SQL statements
such as *Note `CREATE USER': create-user, *Note `GRANT': grant, and
*Note `SET PASSWORD': set-password, so if you use these statements,
they are logged in the history file. To keep this file safe, use a
restrictive access mode, the same way as described earlier for the
`.my.cnf' file.

If your command interpreter is configured to maintain a history, any
file in which the commands are saved will contain MySQL passwords
entered on the command line. For example, `bash' uses
`~/.bash_history'. Any such file should have a restrictive access mode.


File: manual.info,  Node: password-hashing,  Next: application-password-use,  Prev: password-security-user,  Up: password-security

6.3.2.3 Password Hashing in MySQL
.................................

MySQL user accounts are listed in the `user' table of the `mysql'
database. Each MySQL account is assigned a password, although what is
stored in the `Password' column of the `user' table is not the
plaintext version of the password, but a hash value computed from it.
Password hash values are computed by the `PASSWORD()' function.

MySQL uses passwords in two phases of client/server communication:

   * When a client attempts to connect to the server, there is an
     initial authentication step in which the client must present a
     password that has a hash value matching the hash value stored in
     the `user' table for the account that the client wants to use.

   * After the client connects, it can (if it has sufficient
     privileges) set or change the password hashes for accounts listed
     in the `user' table. The client can do this by using the
     `PASSWORD()' function to generate a password hash, or by using the
     *Note `GRANT': grant. or *Note `SET PASSWORD': set-password.
     statements.

In other words, the server _uses_ hash values during authentication
when a client first attempts to connect.  The server _generates_ hash
values if a connected client invokes the `PASSWORD()' function or uses a
*Note `GRANT': grant. or *Note `SET PASSWORD': set-password. statement
to set or change a password.

The password hashing mechanism was updated in MySQL 4.1 to provide
better security and to reduce the risk of passwords being intercepted.
However, this new mechanism is understood only by MySQL 4.1 (and newer)
servers and clients, which can result in some compatibility problems. A
4.1 or newer client can connect to a pre-4.1 server, because the client
understands both the old and new password hashing mechanisms. However,
a pre-4.1 client that attempts to connect to a 4.1 or newer server may
run into difficulties. For example, a 3.23 *Note `mysql': mysql.
client that attempts to connect to a 5.0 server may fail with the
following error message:

     shell> mysql -h localhost -u root
     Client does not support authentication protocol requested
     by server; consider upgrading MySQL client

Another common example of this phenomenon occurs for attempts to use
the older PHP `mysql' extension after upgrading to MySQL 4.1 or newer.
(See *Note apis-php-problems::.)

The following discussion describes the differences between the old and
new password mechanisms, and what you should do if you upgrade your
server but need to maintain backward compatibility with pre-4.1
clients. Additional information can be found in *Note old-client::.
This information is of particular importance to PHP programmers
migrating MySQL databases from version 4.0 or lower to version 4.1 or
higher.

*Note*:

This discussion contrasts 4.1 behavior with pre-4.1 behavior, but the
4.1 behavior described here actually begins with 4.1.1. MySQL 4.1.0 is
an `odd' release because it has a slightly different mechanism than
that implemented in 4.1.1 and up. Differences between 4.1.0 and more
recent versions are described further in MySQL 3.23, 4.0, 4.1 Reference
Manual.

Prior to MySQL 4.1, password hashes computed by the `PASSWORD()'
function are 16 bytes long. Such hashes look like this:

     mysql> SELECT PASSWORD('mypass');
     +--------------------+
     | PASSWORD('mypass') |
     +--------------------+
     | 6f8c114b58f2ce9e   |
     +--------------------+

The `Password' column of the `user' table (in which these hashes are
stored) also is 16 bytes long before MySQL 4.1.

As of MySQL 4.1, the `PASSWORD()' function has been modified to produce
a longer 41-byte hash value:

     mysql> SELECT PASSWORD('mypass');
     +-------------------------------------------+
     | PASSWORD('mypass')                        |
     +-------------------------------------------+
     | *6C8989366EAF75BB670AD8EA7A7FC1176A95CEF4 |
     +-------------------------------------------+

Accordingly, the `Password' column in the `user' table also must be 41
bytes long to store these values:

   * If you perform a new installation of MySQL 5.0, the `Password'
     column is made 41 bytes long automatically.

   * Upgrading from MySQL 4.1 (4.1.1 or later in the 4.1 series) to
     MySQL 5.0 should not give rise to any issues in this regard
     because both versions use the same password hashing mechanism. If
     you wish to upgrade an older release of MySQL to version 5.0, you
     should upgrade to version 4.1 first, then upgrade the 4.1
     installation to 5.0.

A widened `Password' column can store password hashes in both the old
and new formats. The format of any given password hash value can be
determined two ways:

   * The obvious difference is the length (16 bytes versus 41 bytes).

   * A second difference is that password hashes in the new format
     always begin with a ``*'' character, whereas passwords in the old
     format never do.

The longer password hash format has better cryptographic properties,
and client authentication based on long hashes is more secure than that
based on the older short hashes.

The differences between short and long password hashes are relevant
both for how the server uses passwords during authentication and for
how it generates password hashes for connected clients that perform
password-changing operations.

The way in which the server uses password hashes during authentication
is affected by the width of the `Password' column:

   * If the column is short, only short-hash authentication is used.

   * If the column is long, it can hold either short or long hashes,
     and the server can use either format:

        * Pre-4.1 clients can connect, although because they know only
          about the old hashing mechanism, they can authenticate only
          using accounts that have short hashes.

        * 4.1 and later clients can authenticate using accounts that
          have short or long hashes.

Even for short-hash accounts, the authentication process is actually a
bit more secure for 4.1 and later clients than for older clients. In
terms of security, the gradient from least to most secure is:

   * Pre-4.1 client authenticating with short password hash

   * 4.1 or later client authenticating with short password hash

   * 4.1 or later client authenticating with long password hash

The way in which the server generates password hashes for connected
clients is affected by the width of the `Password' column and by the
`--old-passwords' option. A 4.1 or later server generates long hashes
only if certain conditions are met: The `Password' column must be wide
enough to hold long values and the `--old-passwords' option must not be
given. These conditions apply as follows:

   * The `Password' column must be wide enough to hold long hashes (41
     bytes). If the column has not been updated and still has the
     pre-4.1 width of 16 bytes, the server notices that long hashes
     cannot fit into it and generates only short hashes when a client
     performs password-changing operations using `PASSWORD()', *Note
     `GRANT': grant, or *Note `SET PASSWORD': set-password. This is the
     behavior that occurs if you have upgraded to 4.1 but have not yet
     run the *Note `mysql_upgrade': mysql-upgrade. program to widen the
     `Password' column.

   * If the `Password' column is wide, it can store either short or
     long password hashes. In this case, `PASSWORD()', *Note `GRANT':
     grant, and *Note `SET PASSWORD': set-password. generate long
     hashes unless the server was started with the `--old-passwords'
     option. That option forces the server to generate short password
     hashes instead.

The purpose of the `--old-passwords' option is to enable you to
maintain backward compatibility with pre-4.1 clients under
circumstances where the server would otherwise generate long password
hashes. The option does not affect authentication (4.1 and later
clients can still use accounts that have long password hashes), but it
does prevent creation of a long password hash in the `user' table as the
result of a password-changing operation. Were that to occur, the
account no longer could be used by pre-4.1 clients. Without the
`--old-passwords' option, the following undesirable scenario is
possible:

   * An old client connects to an account that has a short password
     hash.

   * The client changes its own password. Without `--old-passwords',
     this results in the account having a long password hash.

   * The next time the old client attempts to connect to the account,
     it cannot, because the account has a long password hash that
     requires the new hashing mechanism during authentication. (Once an
     account has a long password hash in the user table, only 4.1 and
     later clients can authenticate for it, because pre-4.1 clients do
     not understand long hashes.)

This scenario illustrates that, if you must support older pre-4.1
clients, it is dangerous to run a 4.1 or newer server without using the
`--old-passwords' option. By running the server with `--old-passwords',
password-changing operations do not generate long password hashes and
thus do not cause accounts to become inaccessible to older clients.
(Those clients cannot inadvertently lock themselves out by changing
their password and ending up with a long password hash.)

The downside of the `--old-passwords' option is that any passwords you
create or change use short hashes, even for 4.1 clients. Thus, you lose
the additional security provided by long password hashes. If you want
to create an account that has a long hash (for example, for use by 4.1
clients), you must do so while running the server without
`--old-passwords'.

The following scenarios are possible for running a 4.1 or later server:

*Scenario 1:* Short `Password' column in user table:

   * Only short hashes can be stored in the `Password' column.

   * The server uses only short hashes during client authentication.

   * For connected clients, password hash-generating operations
     involving `PASSWORD()', *Note `GRANT': grant, or *Note `SET
     PASSWORD': set-password. use short hashes exclusively. Any change
     to an account's password results in that account having a short
     password hash.

   * The `--old-passwords' option can be used but is superfluous
     because with a short `Password' column, the server generates only
     short password hashes anyway.

*Scenario 2:* Long `Password' column; server not started with
`--old-passwords' option:

   * Short or long hashes can be stored in the `Password' column.

   * 4.1 and later clients can authenticate using accounts that have
     short or long hashes.

   * Pre-4.1 clients can authenticate only using accounts that have
     short hashes.

   * For connected clients, password hash-generating operations
     involving `PASSWORD()', *Note `GRANT': grant, or *Note `SET
     PASSWORD': set-password. use long hashes exclusively. A change to
     an account's password results in that account having a long
     password hash.

As indicated earlier, a danger in this scenario is that it is possible
for accounts that have a short password hash to become inaccessible to
pre-4.1 clients. A change to such an account's password made using
*Note `GRANT': grant, `PASSWORD()', or *Note `SET PASSWORD':
set-password. results in the account being given a long password hash.
From that point on, no pre-4.1 client can authenticate to that account
until the client upgrades to 4.1.

To deal with this problem, you can change a password in a special way.
For example, normally you use *Note `SET PASSWORD': set-password. as
follows to change an account password:

     SET PASSWORD FOR 'SOME_USER'@'SOME_HOST' = PASSWORD('mypass');

To change the password but create a short hash, use the
`OLD_PASSWORD()' function instead:

     SET PASSWORD FOR 'SOME_USER'@'SOME_HOST' = OLD_PASSWORD('mypass');

`OLD_PASSWORD()' is useful for situations in which you explicitly want
to generate a short hash.

*Scenario 3:* Long `Password' column; 4.1 or newer server started with
`--old-passwords' option:

   * Short or long hashes can be stored in the `Password' column.

   * 4.1 and later clients can authenticate for accounts that have
     short or long hashes (but note that it is possible to create long
     hashes only when the server is started without `--old-passwords').

   * Pre-4.1 clients can authenticate only for accounts that have short
     hashes.

   * For connected clients, password hash-generating operations
     involving `PASSWORD()', *Note `GRANT': grant, or *Note `SET
     PASSWORD': set-password. use short hashes exclusively. Any change
     to an account's password results in that account having a short
     password hash.

In this scenario, you cannot create accounts that have long password
hashes, because the `--old-passwords' option prevents generation of
long hashes. Also, if you create an account with a long hash before
using the `--old-passwords' option, changing the account's password
while `--old-passwords' is in effect results in the account being given
a short password, causing it to lose the security benefits of a longer
hash.

The disadvantages for these scenarios may be summarized as follows:

In scenario 1, you cannot take advantage of longer hashes that provide
more secure authentication.

In scenario 2, accounts with short hashes become inaccessible to
pre-4.1 clients if you change their passwords without explicitly using
`OLD_PASSWORD()'.

In scenario 3, `--old-passwords' prevents accounts with short hashes
from becoming inaccessible, but password-changing operations cause
accounts with long hashes to revert to short hashes, and you cannot
change them back to long hashes while `--old-passwords' is in effect.


File: manual.info,  Node: application-password-use,  Prev: password-hashing,  Up: password-security

6.3.2.4 Implications of Password Hashing Changes in MySQL 4.1 for Application Programs
......................................................................................

An upgrade to MySQL version 4.1 or later can cause compatibility issues
for applications that use `PASSWORD()' to generate passwords for their
own purposes. Applications really should not do this, because
`PASSWORD()' should be used only to manage passwords for MySQL
accounts. But some applications use `PASSWORD()' for their own purposes
anyway.

If you upgrade to 4.1 or later from a pre-4.1 version of MySQL and run
the server under conditions where it generates long password hashes, an
application using `PASSWORD()' for its own passwords breaks. The
recommended course of action in such cases is to modify the application
to use another function, such as `SHA1()' or `MD5()', to produce hashed
values.  If that is not possible, you can use the `OLD_PASSWORD()'
function, which is provided for generate short hashes in the old
format. However, you should note that `OLD_PASSWORD()' may one day no
longer be supported.

If the server is running under circumstances where it generates short
hashes, `OLD_PASSWORD()' is available but is equivalent to `PASSWORD()'.

PHP programmers migrating their MySQL databases from version 4.0 or
lower to version 4.1 or higher should see *Note apis-php::.


File: manual.info,  Node: security-against-attack,  Next: privileges-options,  Prev: password-security,  Up: security

6.3.3 Making MySQL Secure Against Attackers
-------------------------------------------

When you connect to a MySQL server, you should use a password. The
password is not transmitted in clear text over the connection.
Password handling during the client connection sequence was upgraded in
MySQL 4.1.1 to be very secure. If you are still using pre-4.1.1-style
passwords, the encryption algorithm is not as strong as the newer
algorithm. With some effort, a clever attacker who can sniff the
traffic between the client and the server can crack the password. (See
*Note password-hashing::, for a discussion of the different password
handling methods.)

All other information is transferred as text, and can be read by anyone
who is able to watch the connection. If the connection between the
client and the server goes through an untrusted network, and you are
concerned about this, you can use the compressed protocol to make
traffic much more difficult to decipher. You can also use MySQL's
internal SSL support to make the connection even more secure. See *Note
secure-connections::. Alternatively, use SSH to get an encrypted TCP/IP
connection between a MySQL server and a MySQL client. You can find an
Open Source SSH client at `http://www.openssh.org/', and a commercial
SSH client at `http://www.ssh.com/'.

To make a MySQL system secure, you should strongly consider the
following suggestions:

   * Require all MySQL accounts to have a password. A client program
     does not necessarily know the identity of the person running it.
     It is common for client/server applications that the user can
     specify any user name to the client program. For example, anyone
     can use the *Note `mysql': mysql. program to connect as any other
     person simply by invoking it as `mysql -u OTHER_USER DB_NAME' if
     OTHER_USER has no password. If all accounts have a password,
     connecting using another user's account becomes much more
     difficult.

     For a discussion of methods for setting passwords, see *Note
     assigning-passwords::.

   * Never run the MySQL server as the Unix `root' user. This is
     extremely dangerous, because any user with the `FILE' privilege is
     able to cause the server to create files as `root' (for example,
     `~root/.bashrc'). To prevent this, *Note `mysqld': mysqld. refuses
     to run as `root' unless that is specified explicitly using the
     `--user=root' option.

     *Note `mysqld': mysqld. can (and should) be run as an ordinary,
     unprivileged user instead. You can create a separate Unix account
     named `mysql' to make everything even more secure. Use this
     account only for administering MySQL. To start *Note `mysqld':
     mysqld. as a different Unix user, add a `user' option that
     specifies the user name in the `[mysqld]' group of the `my.cnf'
     option file where you specify server options. For example:

          [mysqld]
          user=mysql

     This causes the server to start as the designated user whether you
     start it manually or by using *Note `mysqld_safe': mysqld-safe. or
     *Note `mysql.server': mysql-server. For more details, see *Note
     changing-mysql-user::.

     Running *Note `mysqld': mysqld. as a Unix user other than `root'
     does not mean that you need to change the `root' user name in the
     `user' table. _User names for MySQL accounts have nothing to do
     with user names for Unix accounts_.

   * Do not permit the use of symlinks to tables. (This capability can
     be disabled with the `--skip-symbolic-links' option.) This is
     especially important if you run *Note `mysqld': mysqld. as `root',
     because anyone that has write access to the server's data directory
     then could delete any file in the system! See *Note
     symbolic-links-to-tables::.

   * Make sure that the only Unix user account with read or write
     privileges in the database directories is the account that is used
     for running *Note `mysqld': mysqld.

   * Do not grant the `PROCESS' or `SUPER' privilege to
     nonadministrative users. The output of *Note `mysqladmin
     processlist': mysqladmin. and *Note `SHOW PROCESSLIST':
     show-processlist. shows the text of any statements currently being
     executed, so any user who is permitted to see the server process
     list might be able to see statements issued by other users such as
     `UPDATE user SET password=PASSWORD('not_secure')'.

     *Note `mysqld': mysqld. reserves an extra connection for users who
     have the `SUPER' privilege, so that a MySQL `root' user can log in
     and check server activity even if all normal connections are in
     use.

     The `SUPER' privilege can be used to terminate client connections,
     change server operation by changing the value of system variables,
     and control replication servers.

   * Do not grant the `FILE' privilege to nonadministrative users. Any
     user that has this privilege can write a file anywhere in the file
     system with the privileges of the *Note `mysqld': mysqld. daemon.
     To make this a bit safer, files generated with *Note `SELECT ...
     INTO OUTFILE': select-into. do not overwrite existing files and are
     writable by everyone.

     The `FILE' privilege may also be used to read any file that is
     world-readable or accessible to the Unix user that the server runs
     as. With this privilege, you can read any file into a database
     table. This could be abused, for example, by using *Note `LOAD
     DATA': load-data. to load `/etc/passwd' into a table, which then
     can be displayed with *Note `SELECT': select.

   * Stored programs and views should be written using the security
     guidelines discussed in *Note stored-programs-security::.

   * If you do not trust your DNS, you should use IP addresses rather
     than host names in the grant tables. In any case, you should be
     very careful about creating grant table entries using host name
     values that contain wildcards.

   * If you want to restrict the number of connections permitted to a
     single account, you can do so by setting the
     `max_user_connections' variable in *Note `mysqld': mysqld. The
     *Note `GRANT': grant. statement also supports resource control
     options for limiting the extent of server use permitted to an
     account. See *Note grant::.

   * If the plugin directory is writable by the server, it may be
     possible for a user to write executable code to a file in the
     directory using *Note `SELECT ... INTO DUMPFILE': select. This can
     be prevented by making `plugin_dir' read only to the server or by
     setting `--secure-file-priv' to a directory where *Note `SELECT':
     select. writes can be made safely.


File: manual.info,  Node: privileges-options,  Next: load-data-local,  Prev: security-against-attack,  Up: security

6.3.4 Security-Related `mysqld' Options
---------------------------------------

The following *Note `mysqld': mysqld. options affect security:

*Security Option/Variable Summary*

Name           Cmd-Line    Option file System Var  Status Var  Var Scope   Dynamic
allow-suspicious-udfsYes         Yes                                             
automatic_sp_privileges                        Yes                     Global      Yes
chroot         Yes         Yes                                             
des-key-file   Yes         Yes                                             
local_infile                           Yes                     Global      Yes
local-infile   Yes         Yes                                             
- _Variable_:                                                              
local_infile                                                               
old-passwords  Yes         Yes                                 Both        Yes
- _Variable_:                          Yes                     Both        Yes
old_passwords                                                              
safe-show-databaseYes         Yes         Yes                     Global      Yes
safe-user-createYes         Yes                                             
secure-auth    Yes         Yes                                 Global      Yes
- _Variable_:                          Yes                     Global      Yes
secure_auth                                                                
secure-file-privYes         Yes                                 Global      No
- _Variable_:                          Yes                     Global      No
secure_file_priv                                                            
skip-grant-tablesYes         Yes                                             
skip-name-resolveYes         Yes                                 Global      No
- _Variable_:                          Yes                     Global      No
skip_name_resolve                                                            
skip-networkingYes         Yes                                 Global      No
- _Variable_:                          Yes                     Global      No
skip_networking                                                            
skip-show-databaseYes         Yes                                 Global      No
- _Variable_:                          Yes                     Global      No
skip_show_database                                                            

   * `--allow-suspicious-udfs'

     This option controls whether user-defined functions that have only
     an `xxx' symbol for the main function can be loaded. By default,
     the option is off and only UDFs that have at least one auxiliary
     symbol can be loaded; this prevents attempts at loading functions
     from shared object files other than those containing legitimate
     UDFs. For MySQL 5.0, this option was added in MySQL 5.0.3. See
     *Note udf-security::.

   *  `--local-infile[={0|1}]'

     If you start the server with `--local-infile=0', clients cannot
     use `LOCAL' in *Note `LOAD DATA': load-data. statements. See *Note
     load-data-local::.

   * `--old-passwords'

     Force the server to generate short (pre-4.1) password hashes for
     new passwords. This is useful for compatibility when the server
     must support older client programs. See *Note password-hashing::.

   * `--safe-user-create'

     If this option is enabled, a user cannot create new MySQL users by
     using the *Note `GRANT': grant.  statement unless the user has the
     `INSERT' privilege for the `mysql.user' table or any column in the
     table. If you want a user to have the ability to create new users
     that have those privileges that the user has the right to grant,
     you should grant the user the following privilege:

          GRANT INSERT(user) ON mysql.user TO 'USER_NAME'@'HOST_NAME';

     This ensures that the user cannot change any privilege columns
     directly, but has to use the *Note `GRANT': grant. statement to
     give privileges to other users.

   * `--secure-auth'

     Disallow authentication for accounts that have old (pre-4.1)
     passwords.

     The *Note `mysql': mysql. client also has a `--secure-auth'
     option, which prevents connections to a server if the server
     requires a password in old format for the client account.

   * `--secure-file-priv=PATH'

     This option limits the effect of the `LOAD_FILE()' function and the
     *Note `LOAD DATA': load-data. and *Note `SELECT ... INTO OUTFILE':
     select-into. statements to work only with files in the specified
     directory.

     This option was added in MySQL 5.0.38.

   * `--skip-grant-tables'

     This option causes the server not to use the privilege system at
     all. This gives anyone with access to the server _unrestricted
     access_ to _all databases_. You can cause a running server to start
     using the grant tables again by executing *Note `mysqladmin
     flush-privileges': mysqladmin. or *Note `mysqladmin reload':
     mysqladmin. command from a system shell, or by issuing a MySQL
     *Note `FLUSH PRIVILEGES': flush. statement. This option also
     suppresses loading of user-defined functions (UDFs).

   * `--skip-name-resolve'

     Host names are not resolved. All `Host' column values in the grant
     tables must be IP addresses or `localhost'.

   * `--skip-networking'

     Do not permit TCP/IP connections over the network. All connections
     to *Note `mysqld': mysqld. must be made using Unix socket files.

   * `--skip-show-database'

     With this option, the *Note `SHOW DATABASES': show-databases.
     statement is permitted only to users who have the `SHOW DATABASES'
     privilege, and the statement displays all database names.  Without
     this option, *Note `SHOW DATABASES': show-databases. is permitted
     to all users, but displays each database name only if the user has
     the `SHOW DATABASES' privilege or some privilege for the database.
     Note that any global privilege is a privilege for the database.

   *  `--ssl*'

     Options that begin with `--ssl' specify whether to permit clients
     to connect using SSL and indicate where to find SSL keys and
     certificates. See *Note ssl-options::.


File: manual.info,  Node: load-data-local,  Next: changing-mysql-user,  Prev: privileges-options,  Up: security

6.3.5 Security Issues with `LOAD DATA LOCAL'
--------------------------------------------

The *Note `LOAD DATA': load-data. statement can load a file that is
located on the server host, or it can load a file that is located on
the client host when the `LOCAL' keyword is specified.

There are two potential security issues with supporting the `LOCAL'
version of *Note `LOAD DATA': load-data. statements:

   * The transfer of the file from the client host to the server host
     is initiated by the MySQL server. In theory, a patched server
     could be built that would tell the client program to transfer a
     file of the server's choosing rather than the file named by the
     client in the *Note `LOAD DATA': load-data. statement. Such a
     server could access any file on the client host to which the
     client user has read access.

   * In a Web environment where the clients are connecting from a Web
     server, a user could use *Note `LOAD DATA LOCAL': load-data. to
     read any files that the Web server process has read access to
     (assuming that a user could run any command against the SQL
     server). In this environment, the client with respect to the MySQL
     server actually is the Web server, not the remote program being
     run by the user who connects to the Web server.

To deal with these problems, we changed how *Note `LOAD DATA LOCAL':
load-data. is handled as of MySQL 3.23.49 and MySQL 4.0.2 (4.0.13 on
Windows):

   * By default, all MySQL clients and libraries in binary
     distributions are compiled with the `--enable-local-infile'
     option, to be compatible with MySQL 3.23.48 and before.

   * If you build MySQL from source but do not invoke `configure' with
     the `--enable-local-infile' option, *Note `LOAD DATA LOCAL':
     load-data. cannot be used by any client unless it is written
     explicitly to invoke *Note `mysql_options(...
     MYSQL_OPT_LOCAL_INFILE, 0)': mysql-options. See *Note
     mysql-options::.

   * You can disable all *Note `LOAD DATA LOCAL': load-data. statements
     from the server side by starting *Note `mysqld': mysqld. with the
     `--local-infile=0' option.

   * For the *Note `mysql': mysql. command-line client, enable *Note
     `LOAD DATA LOCAL': load-data. by specifying the
     `--local-infile[=1]' option, or disable it with the
     `--local-infile=0' option. For *Note `mysqlimport': mysqlimport,
     local data file loading is off by default; enable it with the
     `--local' or `-L' option. In any case, successful use of a local
     load operation requires that the server permits it.

   * If you use *Note `LOAD DATA LOCAL': load-data. in Perl scripts or
     other programs that read the `[client]' group from option files,
     you can add the `local-infile=1' option to that group. However, to
     keep this from causing problems for programs that do not understand
     `local-infile', specify it using the `loose-' prefix:

          [client]
          loose-local-infile=1

   * If *Note `LOAD DATA LOCAL': load-data. is disabled, either in the
     server or the client, a client that attempts to issue such a
     statement receives the following error message:

          ERROR 1148: The used command is not allowed with this MySQL version


File: manual.info,  Node: changing-mysql-user,  Prev: load-data-local,  Up: security

6.3.6 How to Run MySQL as a Normal User
---------------------------------------

On Windows, you can run the server as a Windows service using a normal
user account.

On Unix, the MySQL server *Note `mysqld': mysqld. can be started and
run by any user. However, you should avoid running the server as the
Unix `root' user for security reasons. To change *Note `mysqld':
mysqld. to run as a normal unprivileged Unix user USER_NAME, you must
do the following:

  1. Stop the server if it is running (use *Note `mysqladmin shutdown':
     mysqladmin.).

  2. Change the database directories and files so that USER_NAME has
     privileges to read and write files in them (you might need to do
     this as the Unix `root' user):

          shell> chown -R USER_NAME /PATH/TO/MYSQL/DATADIR

     If you do not do this, the server will not be able to access
     databases or tables when it runs as USER_NAME.

     If directories or files within the MySQL data directory are
     symbolic links, `chown -R' might not follow symbolic links for
     you. If it does not, you will also need to follow those links and
     change the directories and files they point to.

  3. Start the server as user USER_NAME.  Another alternative is to
     start *Note `mysqld': mysqld. as the Unix `root' user and use the
     `--user=USER_NAME' option. *Note `mysqld': mysqld. starts up, then
     switches to run as the Unix user USER_NAME before accepting any
     connections.

  4. To start the server as the given user automatically at system
     startup time, specify the user name by adding a `user' option to
     the `[mysqld]' group of the `/etc/my.cnf' option file or the
     `my.cnf' option file in the server's data directory. For example:

          [mysqld]
          user=USER_NAME

If your Unix machine itself is not secured, you should assign passwords
to the MySQL `root' accounts in the grant tables. Otherwise, any user
with a login account on that machine can run the *Note `mysql': mysql.
client with a `--user=root' option and perform any operation. (It is a
good idea to assign passwords to MySQL accounts in any case, but
especially so when other login accounts exist on the server host.) See
*Note postinstallation::.


File: manual.info,  Node: privilege-system,  Next: user-account-management,  Prev: security,  Up: server-administration

6.4 The MySQL Access Privilege System
=====================================

* Menu:

* privileges-provided::          Privileges Provided by MySQL
* grant-table-structure::        Privilege System Grant Tables
* account-names::                Specifying Account Names
* connection-access::            Access Control, Stage 1: Connection Verification
* request-access::               Access Control, Stage 2: Request Verification
* privilege-changes::            When Privilege Changes Take Effect
* access-denied::                Causes of Access-Denied Errors

The primary function of the MySQL privilege system is to authenticate a
user who connects from a given host and to associate that user with
privileges on a database such as *Note `SELECT': select, *Note
`INSERT': insert, *Note `UPDATE': update, and *Note `DELETE': delete.
Additional functionality includes the ability to have anonymous users
and to grant privileges for MySQL-specific functions such as *Note
`LOAD DATA INFILE': load-data. and administrative operations.

There are some things that you cannot do with the MySQL privilege
system:

   * You cannot explicitly specify that a given user should be denied
     access. That is, you cannot explicitly match a user and then
     refuse the connection.

   * You cannot specify that a user has privileges to create or drop
     tables in a database but not to create or drop the database itself.

   * A password applies globally to an account. You cannot associate a
     password with a specific object such as a database, table, or
     routine.

The user interface to the MySQL privilege system consists of SQL
statements such as *Note `CREATE USER': create-user, *Note `GRANT':
grant, and *Note `REVOKE': revoke. See *Note account-management-sql::.

Internally, the server stores privilege information in the grant tables
of the `mysql' database (that is, in the database named `mysql'). The
MySQL server reads the contents of these tables into memory when it
starts and bases access-control decisions on the in-memory copies of
the grant tables.

The MySQL privilege system ensures that all users may perform only the
operations permitted to them. As a user, when you connect to a MySQL
server, your identity is determined by _the host from which you
connect_ and _the user name you specify_. When you issue requests after
connecting, the system grants privileges according to your identity and
_what you want to do_.

MySQL considers both your host name and user name in identifying you
because there is no reason to assume that a given user name belongs to
the same person on all hosts. For example, the user `joe' who connects
from `office.example.com' need not be the same person as the user `joe'
who connects from `home.example.com'. MySQL handles this by enabling
you to distinguish users on different hosts that happen to have the
same name: You can grant one set of privileges for connections by `joe'
from `office.example.com', and a different set of privileges for
connections by `joe' from `home.example.com'. To see what privileges a
given account has, use the *Note `SHOW GRANTS': show-grants. statement.
For example:

     SHOW GRANTS FOR 'joe'@'office.example.com';
     SHOW GRANTS FOR 'joe'@'home.example.com';

MySQL access control involves two stages when you run a client program
that connects to the server:

*Stage 1:* The server accepts or rejects the connection based on your
identity and whether you can verify your identity by supplying the
correct password.

*Stage 2:* Assuming that you can connect, the server checks each
statement you issue to determine whether you have sufficient privileges
to perform it. For example, if you try to select rows from a table in a
database or drop a table from the database, the server verifies that
you have the `SELECT' privilege for the table or the `DROP' privilege
for the database.

For a more detailed description of what happens during each stage, see
*Note connection-access::, and *Note request-access::.

If your privileges are changed (either by yourself or someone else)
while you are connected, those changes do not necessarily take effect
immediately for the next statement that you issue. For details about
the conditions under which the server reloads the grant tables, see
*Note privilege-changes::.

For general security-related advice, see *Note security::.  For help in
diagnosing privilege-related problems, see *Note access-denied::.


File: manual.info,  Node: privileges-provided,  Next: grant-table-structure,  Prev: privilege-system,  Up: privilege-system

6.4.1 Privileges Provided by MySQL
----------------------------------

MySQL provides privileges that apply in different contexts and at
different levels of operation:

   * Administrative privileges enable users to manage operation of the
     MySQL server. These privileges are global because they are not
     specific to a particular database.

   * Database privileges apply to a database and to all objects within
     it. These privileges can be granted for specific databases, or
     globally so that they apply to all databases.

   * Privileges for database objects such as tables, indexes, views,
     and stored routines can be granted for specific objects within a
     database, for all objects of a given type within a database (for
     example, all tables in a database), or globally for all objects of
     a given type in all databases).

Information about account privileges is stored in the `user', `db',
`host', `tables_priv', `columns_priv', and `procs_priv' tables in the
`mysql' database (see *Note grant-table-structure::). The MySQL server
reads the contents of these tables into memory when it starts and
reloads them under the circumstances indicated in *Note
privilege-changes::. Access-control decisions are based on the
in-memory copies of the grant tables.

Some releases of MySQL introduce changes to the structure of the grant
tables to add new access privileges or features. Whenever you update to
a new version of MySQL, you should update your grant tables to make
sure that they have the current structure so that you can take
advantage of any new capabilities. See *Note mysql-upgrade::.

The following table shows the privilege names used at the SQL level in
the *Note `GRANT': grant. and *Note `REVOKE': revoke. statements, along
with the column name associated with each privilege in the grant tables
and the context in which the privilege applies.

*Permissible Privileges for `GRANT' and `REVOKE'*

Privilege              Column                   Context
`CREATE'               `Create_priv'            databases, tables, or
                                                indexes
`DROP'                 `Drop_priv'              databases, tables, or views
`GRANT OPTION'         `Grant_priv'             databases, tables, or
                                                stored routines
`LOCK TABLES'          `Lock_tables_priv'       databases
`REFERENCES'           `References_priv'        databases or tables
`ALTER'                `Alter_priv'             tables
`DELETE'               `Delete_priv'            tables
`INDEX'                `Index_priv'             tables
`INSERT'               `Insert_priv'            tables or columns
`SELECT'               `Select_priv'            tables or columns
`UPDATE'               `Update_priv'            tables or columns
`CREATE TEMPORARY      `Create_tmp_table_priv'  tables
TABLES'                                         
`CREATE VIEW'          `Create_view_priv'       views
`SHOW VIEW'            `Show_view_priv'         views
`ALTER ROUTINE'        `Alter_routine_priv'     stored routines
`CREATE ROUTINE'       `Create_routine_priv'    stored routines
`EXECUTE'              `Execute_priv'           stored routines
`FILE'                 `File_priv'              file access on server host
`CREATE USER'          `Create_user_priv'       server administration
`PROCESS'              `Process_priv'           server administration
`RELOAD'               `Reload_priv'            server administration
`REPLICATION CLIENT'   `Repl_client_priv'       server administration
`REPLICATION SLAVE'    `Repl_slave_priv'        server administration
`SHOW DATABASES'       `Show_db_priv'           server administration
`SHUTDOWN'             `Shutdown_priv'          server administration
`SUPER'                `Super_priv'             server administration
`ALL [PRIVILEGES]'                              server administration
`USAGE'                                         server administration

The following list provides a general description of each privilege
available in MySQL. Particular SQL statements might have more specific
privilege requirements than indicated here. If so, the description for
the statement in question provides the details.

   *  The `ALL' or `ALL PRIVILEGES' privilege specifier is shorthand.
     It stands for `all privileges available at a given privilege level'
     (except `GRANT OPTION'). For example, granting `ALL' at the global
     or table level grants all global privileges or all table-level
     privileges.

   *  The `ALTER' privilege enables use of *Note `ALTER TABLE':
     alter-table. to change the structure of tables. *Note `ALTER
     TABLE': alter-table. also requires the `CREATE' and `INSERT'
     privileges. Renaming a table requires `ALTER' and `DROP' on the
     old table, `ALTER', `CREATE', and `INSERT' on the new table.

   *  The `ALTER ROUTINE' privilege is needed to alter or drop stored
     routines (procedures and functions). This privilege was added in
     MySQL 5.0.3.

   *  The `CREATE' privilege enables creation of new databases and
     tables.

   *  The `CREATE ROUTINE' privilege is needed to create stored
     routines (procedures and functions).  This privilege was added in
     MySQL 5.0.3.

   *  The `CREATE TEMPORARY TABLES' privilege enables the creation of
     temporary tables using the *Note `CREATE TEMPORARY TABLE':
     create-table. statement.

     However, other operations on a temporary table, such as *Note
     `INSERT': insert, *Note `UPDATE': update, or *Note `SELECT':
     select, require additional privileges for those operations for the
     database containing the temporary table, or for the nontemporary
     table of the same name.

     To keep privileges for temporary and nontemporary tables separate,
     a common workaround for this situation is to create a database
     dedicated to the use of temporary tables. Then for that database,
     a user can be granted the `CREATE TEMPORARY TABLES' privilege,
     along with any other privileges required for temporary table
     operations done by that user.

   *  The `CREATE USER' privilege enables use of *Note `CREATE USER':
     create-user, *Note `DROP USER': drop-user, *Note `RENAME USER':
     rename-user, and *Note `REVOKE ALL PRIVILEGES': revoke. This
     privilege was added in MySQL 5.0.3.

   *  The `CREATE VIEW' privilege enables use of *Note `CREATE VIEW':
     create-view.  This privilege was added in MySQL 5.0.1.

   *  The `DELETE' privilege enables rows to be deleted from tables in
     a database.

   *  The `DROP' privilege enables you to drop (remove) existing
     databases and tables. _If you grant the `DROP' privilege for the
     `mysql' database to a user, that user can drop the database in
     which the MySQL access privileges are stored._

   *  The `EXECUTE' privilege is required to execute stored routines
     (procedures and functions). This privilege was added in MySQL
     5.0.0 but did not become operational until MySQL 5.0.3.

   *  The `FILE' privilege gives you permission to read and write files
     on the server host using the *Note `LOAD DATA INFILE': load-data.
     and *Note `SELECT ... INTO OUTFILE': select-into. statements and
     the `LOAD_FILE()' function. A user who has the `FILE' privilege can
     read any file on the server host that is either world-readable or
     readable by the MySQL server. (This implies the user can read any
     file in any database directory, because the server can access any
     of those files.) The `FILE' privilege also enables the user to
     create new files in any directory where the MySQL server has write
     access. As a security measure, the server will not overwrite
     existing files.

   *  The `GRANT OPTION' privilege enables you to give to other users
     or remove from other users those privileges that you yourself
     possess.

   *  The `INDEX' privilege enables you to create or drop (remove)
     indexes.  `INDEX' applies to existing tables. If you have the
     `CREATE' privilege for a table, you can include index definitions
     in the *Note `CREATE TABLE': create-table. statement.

   *  The `INSERT' privilege enables rows to be inserted into tables in
     a database.  `INSERT' is also required for the *Note `ANALYZE
     TABLE': analyze-table, *Note `OPTIMIZE TABLE': optimize-table, and
     *Note `REPAIR TABLE': repair-table. table-maintenance statements.

   *  The `LOCK TABLES' privilege enables the use of explicit *Note
     `LOCK TABLES': lock-tables. statements to lock tables for which
     you have the `SELECT' privilege. This includes the use of write
     locks, which prevents other sessions from reading the locked table.

   *  The `PROCESS' privilege pertains to display of information about
     the threads executing within the server (that is, information
     about the statements being executed by sessions). The privilege
     enables use of *Note `SHOW PROCESSLIST': show-processlist. or
     *Note `mysqladmin processlist': mysqladmin. to see threads
     belonging to other accounts; you can always see your own threads.

   *  The `REFERENCES' privilege currently is unused.

   *  The `RELOAD' privilege enables use of the *Note `FLUSH': flush.
     statement. It also enables *Note `mysqladmin': mysqladmin.
     commands that are equivalent to *Note `FLUSH': flush. operations:
     `flush-hosts', `flush-logs', `flush-privileges', `flush-status',
     `flush-tables', `flush-threads', `refresh', and `reload'.

     The `reload' command tells the server to reload the grant tables
     into memory.  `flush-privileges' is a synonym for `reload'. The
     `refresh' command closes and reopens the log files and flushes all
     tables. The other `flush-XXX' commands perform functions similar to
     `refresh', but are more specific and may be preferable in some
     instances. For example, if you want to flush just the log files,
     `flush-logs' is a better choice than `refresh'.

   *  The `REPLICATION CLIENT' privilege enables the use of *Note `SHOW
     MASTER STATUS': show-master-status. and *Note `SHOW SLAVE STATUS':
     show-slave-status.

   *  The `REPLICATION SLAVE' privilege should be granted to accounts
     that are used by slave servers to connect to the current server as
     their master. Without this privilege, the slave cannot request
     updates that have been made to databases on the master server.

   *  The `SELECT' privilege enables you to select rows from tables in
     a database.  *Note `SELECT': select. statements require the
     `SELECT' privilege only if they actually retrieve rows from a
     table. Some *Note `SELECT': select. statements do not access
     tables and can be executed without permission for any database.
     For example, you can use *Note `SELECT': select. as a simple
     calculator to evaluate expressions that make no reference to
     tables:

          SELECT 1+1;
          SELECT PI()*2;

     The `SELECT' privilege is also needed for other statements that
     read column values. For example, `SELECT' is needed for columns
     referenced on the right hand side of COL_NAME=EXPR assignment in
     *Note `UPDATE': update. statements or for columns named in the
     `WHERE' clause of *Note `DELETE': delete. or *Note `UPDATE':
     update. statements.

   *  The `SHOW DATABASES' privilege enables the account to see
     database names by issuing the `SHOW DATABASE' statement. Accounts
     that do not have this privilege see only databases for which they
     have some privileges, and cannot use the statement at all if the
     server was started with the `--skip-show-database' option.  Note
     that _any_ global privilege is a privilege for the database.

   *  The `SHOW VIEW' privilege enables use of *Note `SHOW CREATE
     VIEW': show-create-view. This privilege was added in MySQL 5.0.1.

   *  The `SHUTDOWN' privilege enables use of the *Note `mysqladmin
     shutdown': mysqladmin. command.  There is no corresponding SQL
     statement.

   *  The `SUPER' privilege enables an account to use *Note `CHANGE
     MASTER TO': change-master-to, *Note `KILL': kill. or *Note
     `mysqladmin kill': mysqladmin. to kill threads belonging to other
     accounts (you can always kill your own threads), *Note `PURGE
     BINARY LOGS': purge-binary-logs, configuration changes using *Note
     `SET GLOBAL': set-option. to modify global system variables, the
     *Note `mysqladmin debug': mysqladmin. command, enabling or
     disabling logging, performing updates even if the `read_only'
     system variable is enabled, starting and stopping replication on
     slave servers, specification of any account in the `DEFINER'
     attribute of stored programs and views, and enables you to connect
     (once) even if the connection limit controlled by the
     `max_connections' system variable is reached.

     To create or alter stored routines if binary logging is enabled,
     you may also need the `SUPER' privilege, as described in *Note
     stored-programs-logging::.

   *  The `UPDATE' privilege enables rows to be updated in tables in a
     database.

   *  The `USAGE' privilege specifier stands for `no privileges.' It is
     used at the global level with *Note `GRANT': grant. to modify
     account attributes such as resource limits or SSL characteristics
     without affecting existing account privileges.

It is a good idea to grant to an account only those privileges that it
needs. You should exercise particular caution in granting the `FILE'
and administrative privileges:

   * The `FILE' privilege can be abused to read into a database table
     any files that the MySQL server can read on the server host. This
     includes all world-readable files and files in the server's data
     directory.  The table can then be accessed using *Note `SELECT':
     select. to transfer its contents to the client host.

   * The `GRANT OPTION' privilege enables users to give their
     privileges to other users. Two users that have different
     privileges and with the `GRANT OPTION' privilege are able to
     combine privileges.

   * The `ALTER' privilege may be used to subvert the privilege system
     by renaming tables.

   * The `SHUTDOWN' privilege can be abused to deny service to other
     users entirely by terminating the server.

   * The `PROCESS' privilege can be used to view the plain text of
     currently executing statements, including statements that set or
     change passwords.

   * The `SUPER' privilege can be used to terminate other sessions or
     change how the server operates.

   * Privileges granted for the `mysql' database itself can be used to
     change passwords and other access privilege information. Passwords
     are stored encrypted, so a malicious user cannot simply read them
     to know the plain text password. However, a user with write access
     to the `user' table `Password' column can change an account's
     password, and then connect to the MySQL server using that account.


File: manual.info,  Node: grant-table-structure,  Next: account-names,  Prev: privileges-provided,  Up: privilege-system

6.4.2 Privilege System Grant Tables
-----------------------------------

Normally, you manipulate the contents of the grant tables in the
`mysql' database indirectly by using statements such as *Note `GRANT':
grant. and *Note `REVOKE': revoke. to set up accounts and control the
privileges available to each one. See *Note account-management-sql::.
The discussion here describes the underlying structure of the grant
tables and how the server uses their contents when interacting with
clients.

These `mysql' database tables contain grant information:

   * `user': Contains user accounts, global privileges, and other
     non-privilege columns.

   * `db': Contains database-level privileges.

   * `host': Obsolete.

   * `tables_priv': Contains table-level privileges.

   * `columns_priv': Contains column-level privileges.

   * `procs_priv': Contains stored procedure and function privileges.

Other tables in the `mysql' database do not hold grant information and
are discussed elsewhere:

   * `func': Contains information about user-defined functions: See
     *Note adding-functions::.

   * `help_XXX': These tables are used for server-side help: See *Note
     server-side-help-support::.

   * `proc': Contains information about stored procedures and
     functions: See *Note stored-routines::.

   * `time_zone_XXX': These tables contain time zone information: See
     *Note time-zone-support::.

Each grant table contains scope columns and privilege columns:

   * Scope columns determine the scope of each row (entry) in the
     tables; that is, the context in which the row applies. For
     example, a `user' table row with `Host' and `User' values of
     `'thomas.loc.gov'' and `'bob'' would be used for authenticating
     connections made to the server from the host `thomas.loc.gov' by a
     client that specifies a user name of `bob'. Similarly, a `db'
     table row with `Host', `User', and `Db' column values of
     `'thomas.loc.gov'', `'bob'' and `'reports'' would be used when
     `bob' connects from the host `thomas.loc.gov' to access the
     `reports' database. The `tables_priv' and `columns_priv' tables
     contain scope columns indicating tables or table/column
     combinations to which each row applies. The `procs_priv' scope
     columns indicate the stored routine to which each row applies.

   * Privilege columns indicate which privileges are granted by a table
     row; that is, what operations can be performed. The server
     combines the information in the various grant tables to form a
     complete description of a user's privileges.  *Note
     request-access::, describes the rules that are used to do this.

The server uses the grant tables in the following manner:

   * The `user' table scope columns determine whether to reject or
     permit incoming connections. For permitted connections, any
     privileges granted in the `user' table indicate the user's global
     privileges. Any privilege granted in this table applies to _all_
     databases on the server.

     *Note*:

     Because any global privilege is considered a privilege for all
     databases, any global privilege enables a user to see all database
     names with *Note `SHOW DATABASES': show-databases. or by examining
     the *Note `SCHEMATA': schemata-table. table of
     `INFORMATION_SCHEMA'.

   * The `db' table scope columns determine which users can access
     which databases from which hosts. The privilege columns determine
     which operations are permitted. A privilege granted at the
     database level applies to the database and to all objects in the
     database, such as tables and stored programs.

   * The `host' table is used in conjunction with the `db' table when
     you want a given `db' table row to apply to several hosts. For
     example, if you want a user to be able to use a database from
     several hosts in your network, leave the `Host' value empty in the
     user's `db' table row, then populate the `host' table with a row
     for each of those hosts. This mechanism is described more detail in
     *Note request-access::.

     *Note*:

     The `host' table must be modified directly with statements such as
     *Note `INSERT': insert, *Note `UPDATE': update, and *Note
     `DELETE': delete. It is not affected by statements such as *Note
     `GRANT': grant. and *Note `REVOKE': revoke. that modify the grant
     tables indirectly. Most MySQL installations need not use this
     table at all.

   * The `tables_priv' and `columns_priv' tables are similar to the
     `db' table, but are more fine-grained: They apply at the table and
     column levels rather than at the database level. A privilege
     granted at the table level applies to the table and to all its
     columns. A privilege granted at the column level applies only to a
     specific column.

   * The `procs_priv' table applies to stored routines. A privilege
     granted at the routine level applies only to a single routine.

The server uses the `user', `db', and `host' tables in the `mysql'
database at both the first and second stages of access control (see
*Note privilege-system::).  The columns in the `user' and `db' tables
are shown here. The `host' table is similar to the `db' table but has a
specialized use as described in *Note request-access::.

*`user' and `db' Table Columns*

Table Name                    `user'                 `db'
*Scope columns*               `Host'                 `Host'
                              `User'                 `Db'
                              `Password'             `User'
*Privilege columns*           `Select_priv'          `Select_priv'
                              `Insert_priv'          `Insert_priv'
                              `Update_priv'          `Update_priv'
                              `Delete_priv'          `Delete_priv'
                              `Index_priv'           `Index_priv'
                              `Alter_priv'           `Alter_priv'
                              `Create_priv'          `Create_priv'
                              `Drop_priv'            `Drop_priv'
                              `Grant_priv'           `Grant_priv'
                              `Create_view_priv'     `Create_view_priv'
                              `Show_view_priv'       `Show_view_priv'
                              `Create_routine_priv'  `Create_routine_priv'
                              `Alter_routine_priv'   `Alter_routine_priv'
                              `Execute_priv'         `Execute_priv'
                              `Create_tmp_table_priv'`Create_tmp_table_priv'
                              `Lock_tables_priv'     `Lock_tables_priv'
                              `References_priv'      `References_priv'
                              `Reload_priv'          
                              `Shutdown_priv'        
                              `Process_priv'         
                              `File_priv'            
                              `Show_db_priv'         
                              `Super_priv'           
                              `Repl_slave_priv'      
                              `Repl_client_priv'     
                              `Create_user_priv'     
*Security columns*            `ssl_type'             
                              `ssl_cipher'           
                              `x509_issuer'          
                              `x509_subject'         
*Resource control columns*    `max_questions'        
                              `max_updates'          
                              `max_connections'      
                              `max_user_connections' 

`Execute_priv' was present in MySQL 5.0.0, but did not become
operational until MySQL 5.0.3.

The `Create_view_priv' and `Show_view_priv' columns were added in MySQL
5.0.1.

The `Create_routine_priv', `Alter_routine_priv', and
`max_user_connections' columns were added in MySQL 5.0.3.

During the second stage of access control, the server performs request
verification to make sure that each client has sufficient privileges
for each request that it issues. In addition to the `user', `db', and
`host' grant tables, the server may also consult the `tables_priv' and
`columns_priv' tables for requests that involve tables. The latter
tables provide finer privilege control at the table and column levels.
They have the columns shown in the following table.

*`tables_priv' and `columns_priv' Table Columns*

Table Name     `tables_priv'  `columns_priv'
*Scope         `Host'         `Host'
columns*                      
               `Db'           `Db'
               `User'         `User'
               `Table_name'   `Table_name'
                              `Column_name'
*Privilege     `Table_priv'   `Column_priv'
columns*                      
               `Column_priv'  
*Other         `Timestamp'    `Timestamp'
columns*                      
               `Grantor'      

The `Timestamp' and `Grantor' columns currently are unused and are
discussed no further here.

For verification of requests that involve stored routines, the server
may consult the `procs_priv' table, which has the columns shown in the
following table.

*`procs_priv' Table Columns*

Table Name     `procs_priv'
*Scope         `Host'
columns*       
               `Db'
               `User'
               `Routine_name'
               `Routine_type'
*Privilege     `Proc_priv'
columns*       
*Other         `Timestamp'
columns*       
               `Grantor'

The `procs_priv' table exists as of MySQL 5.0.3.  The `Routine_type'
column was added in MySQL 5.0.6. It is an *Note `ENUM': enum. column
with values of `'FUNCTION'' or `'PROCEDURE'' to indicate the type of
routine the row refers to. This column enables privileges to be granted
separately for a function and a procedure with the same name.

The `Timestamp' and `Grantor' columns currently are unused and are
discussed no further here.

Scope columns in the grant tables contain strings. They are declared as
shown here; the default value for each is the empty string.

*Grant Table Scope Column Types*

Column Name    Type
`Host'         `CHAR(60)'
`User'         `CHAR(16)'
`Password'     `CHAR(41)'
`Db'           `CHAR(64)'
`Table_name'   `CHAR(64)'
`Column_name'  `CHAR(64)'
`Routine_name' `CHAR(64)'

For access-checking purposes, comparisons of `User', `Password', `Db',
and `Table_name' values are case sensitive. Comparisons of `Host',
`Column_name', and `Routine_name' values are not case sensitive.

In the `user', `db', and `host' tables, each privilege is listed in a
separate column that is declared as `ENUM('N','Y') DEFAULT 'N''. In
other words, each privilege can be disabled or enabled, with the
default being disabled.

In the `tables_priv', `columns_priv', and `procs_priv' tables, the
privilege columns are declared as *Note `SET': set. columns. Values in
these columns can contain any combination of the privileges controlled
by the table. Only those privileges listed in the column value are
enabled.

*Set-Type Privilege Column Values*

Table Name     Column Name        Possible Set Elements
`tables_priv'  `Table_priv'       `'Select', 'Insert', 'Update',
                                  'Delete', 'Create', 'Drop',
                                  'Grant', 'References', 'Index',
                                  'Alter', 'Create View', 'Show
                                  view''
`tables_priv'  `Column_priv'      `'Select', 'Insert', 'Update',
                                  'References''
`columns_priv' `Column_priv'      `'Select', 'Insert', 'Update',
                                  'References''
`procs_priv'   `Proc_priv'        `'Execute', 'Alter Routine',
                                  'Grant''

Administrative privileges (such as `RELOAD' or `SHUTDOWN') are
specified only in the `user' table. Administrative operations are
operations on the server itself and are not database-specific, so there
is no reason to list these privileges in the other grant tables.
Consequently, to determine whether you can perform an administrative
operation, the server need consult only the `user' table.

The `FILE' privilege also is specified only in the `user' table. It is
not an administrative privilege as such, but your ability to read or
write files on the server host is independent of the database you are
accessing.

The *Note `mysqld': mysqld. server reads the contents of the grant
tables into memory when it starts. You can tell it to reload the tables
by issuing a *Note `FLUSH PRIVILEGES': flush.  statement or executing a
*Note `mysqladmin flush-privileges': mysqladmin. or *Note `mysqladmin
reload': mysqladmin.  command. Changes to the grant tables take effect
as indicated in *Note privilege-changes::.

When you modify an account's privileges, it is a good idea to verify
that the changes set up privileges the way you want. To check the
privileges for a given account, use the *Note `SHOW GRANTS':
show-grants. statement (see *Note show-grants::). For example, to
determine the privileges that are granted to an account with user name
and host name values of `bob' and `pc84.example.com', use this
statement:

     SHOW GRANTS FOR 'bob'@'pc84.example.com';


File: manual.info,  Node: account-names,  Next: connection-access,  Prev: grant-table-structure,  Up: privilege-system

6.4.3 Specifying Account Names
------------------------------

MySQL account names consist of a user name and a host name. This
enables creation of accounts for users with the same name who can
connect from different hosts. This section describes how to write
account names, including special values and wildcard rules.

In SQL statements such as *Note `CREATE USER': create-user, *Note
`GRANT': grant, and *Note `SET PASSWORD': set-password, write account
names using the following rules:

   * Syntax for account names is `'USER_NAME'@'HOST_NAME''.

   * An account name consisting only of a user name is equivalent to
     `'USER_NAME'@'%''.  For example, `'me'' is equivalent to
     `'me'@'%''.

   * The user name and host name need not be quoted if they are legal
     as unquoted identifiers. Quotes are necessary to specify a
     USER_NAME string containing special characters (such as ``-''), or
     a HOST_NAME string containing special characters or wildcard
     characters (such as ``%''); for example, `'test-user'@'%.com''.

   * Quote user names and host names as identifiers or as strings,
     using either backticks (```''), single quotation marks (``'''), or
     double quotation marks (``"'').

   * The user name and host name parts, if quoted, must be quoted
     separately. That is, write `'me'@'localhost'', not
     `'me@localhost''; the latter is interpreted as
     `'me@localhost'@'%''.

MySQL stores account names in grant tables in the `mysql' database
using separate columns for the user name and host name parts:

   * The `user' table contains one row for each account. The `User' and
     `Host' columns store the user name and host name. This table also
     indicates which global privileges the account has.

   * Other grant tables indicate privileges an account has for
     databases and objects within databases. These tables have `User'
     and `Host' columns to store the account name. Each row in these
     tables associates with the account in the `user' table that has
     the same `User' and `Host' values.

   * A reference to the `CURRENT_USER()' (or `CURRENT_USER') function is
     equivalent to specifying the current user's name and host name
     literally.

For additional detail about grant table structure, see *Note
grant-table-structure::.

User names and host names have certain special values or wildcard
conventions, as described following.

A user name is either a nonblank value that literally matches the user
name for incoming connection attempts, or a blank value (empty string)
that matches any user name. An account with a blank user name is an
anonymous user. To specify an anonymous user in SQL statements, use a
quoted empty user name part, such as `''@'localhost''.

The host name part of an account name can take many forms, and
wildcards are permitted:

   * A host value can be a host name or an IP address. The name
     `'localhost'' indicates the local host. The IP address
     `'127.0.0.1'' indicates the loopback interface.

   * You can use the wildcard characters ``%'' and ``_'' in host
     values. These have the same meaning as for pattern-matching
     operations performed with the `LIKE' operator. For example, a host
     value of `'%'' matches any host name, whereas a value of
     `'%.mysql.com'' matches any host in the `mysql.com' domain.
     `'192.168.1.%'' matches any host in the 192.168.1 class C network.

     Because you can use IP wildcard values in host values (for
     example, `'192.168.1.%'' to match every host on a subnet), someone
     could try to exploit this capability by naming a host
     `192.168.1.somewhere.com'. To foil such attempts, MySQL disallows
     matching on host names that start with digits and a dot. Thus, if
     you have a host named something like `1.2.example.com', its name
     never matches the host part of account names. An IP wildcard value
     can match only IP addresses, not host names.

   * For a host value specified as an IP address, you can specify a
     netmask indicating how many address bits to use for the network
     number. The syntax is `HOST_IP/NETMASK'.  For example:

          CREATE USER 'david'@'192.58.197.0/255.255.255.0';

     This enables `david' to connect from any client host having an IP
     address CLIENT_IP for which the following condition is true:

          CLIENT_IP & NETMASK = HOST_IP

     That is, for the *Note `CREATE USER': create-user.  statement just
     shown:

          CLIENT_IP & 255.255.255.0 = 192.58.197.0

     IP addresses that satisfy this condition and can connect to the
     MySQL server are those in the range from `192.58.197.0' to
     `192.58.197.255'.

     The netmask can only be used to tell the server to use 8, 16, 24,
     or 32 bits of the address. Examples:

        * `192.0.0.0/255.0.0.0': Any host on the 192 class A network

        * `192.168.0.0/255.255.0.0': Any host on the 192.168 class B
          network

        * `192.168.1.0/255.255.255.0': Any host on the 192.168.1 class
          C network

        * `192.168.1.1': Only the host with this specific IP address

     The following netmask will not work because it masks 28 bits, and
     28 is not a multiple of 8:

          192.168.0.1/255.255.255.240


File: manual.info,  Node: connection-access,  Next: request-access,  Prev: account-names,  Up: privilege-system

6.4.4 Access Control, Stage 1: Connection Verification
------------------------------------------------------

When you attempt to connect to a MySQL server, the server accepts or
rejects the connection based on your identity and whether you can
verify your identity by supplying the correct password. If not, the
server denies access to you completely. Otherwise, the server accepts
the connection, and then enters Stage 2 and waits for requests.

Your identity is based on two pieces of information:

   * The client host from which you connect

   * Your MySQL user name

Identity checking is performed using the three `user' table scope
columns (`Host', `User', and `Password'). The server accepts the
connection only if the `Host' and `User' columns in some `user' table
row match the client host name and user name and the client supplies
the password specified in that row. The rules for permissible `Host'
and `User' values are given in *Note account-names::.

If the `User' column value is nonblank, the user name in an incoming
connection must match exactly. If the `User' value is blank, it matches
any user name.  If the `user' table row that matches an incoming
connection has a blank user name, the user is considered to be an
anonymous user with no name, not a user with the name that the client
actually specified. This means that a blank user name is used for all
further access checking for the duration of the connection (that is,
during Stage 2).

The `Password' column can be blank. This is not a wildcard and does not
mean that any password matches. It means that the user must connect
without specifying a password.

Nonblank `Password' values in the `user' table represent encrypted
passwords. MySQL does not store passwords in plaintext form for anyone
to see.  Rather, the password supplied by a user who is attempting to
connect is encrypted (using the `PASSWORD()' function). The encrypted
password then is used during the connection process when checking
whether the password is correct. This is done without the encrypted
password ever traveling over the connection. See *Note user-names::.

From MySQL's point of view, the encrypted password is the _real_
password, so you should never give anyone access to it. In particular,
_do not give nonadministrative users read access to tables in the
`mysql' database_.

The following table shows how various combinations of `Host' and `User'
values in the `user' table apply to incoming connections.

`Host' Value              `User'      Permissible Connections
                          Value       
`'thomas.loc.gov''        `'fred''    `fred', connecting from
                                      `thomas.loc.gov'
`'thomas.loc.gov''        `'''        Any user, connecting from
                                      `thomas.loc.gov'
`'%''                     `'fred''    `fred', connecting from any host
`'%''                     `'''        Any user, connecting from any host
`'%.loc.gov''             `'fred''    `fred', connecting from any host in
                                      the `loc.gov' domain
`'x.y.%''                 `'fred''    `fred', connecting from `x.y.net',
                                      `x.y.com', `x.y.edu', and so on;
                                      this is probably not useful
`'144.155.166.177''       `'fred''    `fred', connecting from the host
                                      with IP address `144.155.166.177'
`'144.155.166.%''         `'fred''    `fred', connecting from any host in
                                      the `144.155.166' class C subnet
`'144.155.166.0/255.255.255.0''`'fred''    Same as previous example

It is possible for the client host name and user name of an incoming
connection to match more than one row in the `user' table. The
preceding set of examples demonstrates this: Several of the entries
shown match a connection from `thomas.loc.gov' by `fred'.

When multiple matches are possible, the server must determine which of
them to use. It resolves this issue as follows:

   * Whenever the server reads the `user' table into memory, it sorts
     the rows.

   * When a client attempts to connect, the server looks through the
     rows in sorted order.

   * The server uses the first row that matches the client host name
     and user name.

The server uses sorting rules that order rows with the most-specific
`Host' values first. Literal host names and IP addresses are the most
specific. (The specificity of a literal IP address is not affected by
whether it has a netmask, so `192.168.1.13' and
`192.168.1.0/255.255.255.0' are considered equally specific.) The
pattern `'%'' means `any host' and is least specific. The empty string
`''' also means `any host' but sorts after `'%''. Rows with the same
`Host' value are ordered with the most-specific `User' values first (a
blank `User' value means `any user' and is least specific).

To see how this works, suppose that the `user' table looks like this:

     +-----------+----------+-
     | Host      | User     | ...
     +-----------+----------+-
     | %         | root     | ...
     | %         | jeffrey  | ...
     | localhost | root     | ...
     | localhost |          | ...
     +-----------+----------+-

When the server reads the table into memory, it sorts the rows using
the rules just described. The result after sorting looks like this:

     +-----------+----------+-
     | Host      | User     | ...
     +-----------+----------+-
     | localhost | root     | ...
     | localhost |          | ...
     | %         | jeffrey  | ...
     | %         | root     | ...
     +-----------+----------+-

When a client attempts to connect, the server looks through the sorted
rows and uses the first match found. For a connection from `localhost'
by `jeffrey', two of the rows from the table match: the one with `Host'
and `User' values of `'localhost'' and `''', and the one with values of
`'%'' and `'jeffrey''. The `'localhost'' row appears first in sorted
order, so that is the one the server uses.

Here is another example. Suppose that the `user' table looks like this:

     +----------------+----------+-
     | Host           | User     | ...
     +----------------+----------+-
     | %              | jeffrey  | ...
     | thomas.loc.gov |          | ...
     +----------------+----------+-

The sorted table looks like this:

     +----------------+----------+-
     | Host           | User     | ...
     +----------------+----------+-
     | thomas.loc.gov |          | ...
     | %              | jeffrey  | ...
     +----------------+----------+-

A connection by `jeffrey' from `thomas.loc.gov' is matched by the first
row, whereas a connection by `jeffrey' from any host is matched by the
second.

*Note*:

It is a common misconception to think that, for a given user name, all
rows that explicitly name that user are used first when the server
attempts to find a match for the connection.  This is not true. The
preceding example illustrates this, where a connection from
`thomas.loc.gov' by `jeffrey' is first matched not by the row
containing `'jeffrey'' as the `User' column value, but by the row with
no user name. As a result, `jeffrey' is authenticated as an anonymous
user, even though he specified a user name when connecting.

If you are able to connect to the server, but your privileges are not
what you expect, you probably are being authenticated as some other
account. To find out what account the server used to authenticate you,
use the `CURRENT_USER()' function. (See *Note information-functions::.)
It returns a value in `USER_NAME@HOST_NAME' format that indicates the
`User' and `Host' values from the matching `user' table row. Suppose
that `jeffrey' connects and issues the following query:

     mysql> SELECT CURRENT_USER();
     +----------------+
     | CURRENT_USER() |
     +----------------+
     | @localhost     |
     +----------------+

The result shown here indicates that the matching `user' table row had
a blank `User' column value. In other words, the server is treating
`jeffrey' as an anonymous user.

Another way to diagnose authentication problems is to print out the
`user' table and sort it by hand to see where the first match is being
made.


File: manual.info,  Node: request-access,  Next: privilege-changes,  Prev: connection-access,  Up: privilege-system

6.4.5 Access Control, Stage 2: Request Verification
---------------------------------------------------

After you establish a connection, the server enters Stage 2 of access
control. For each request that you issue through that connection, the
server determines what operation you want to perform, then checks
whether you have sufficient privileges to do so. This is where the
privilege columns in the grant tables come into play. These privileges
can come from any of the `user', `db', `host', `tables_priv',
`columns_priv', or `procs_priv' tables. (You may find it helpful to
refer to *Note grant-table-structure::, which lists the columns present
in each of the grant tables.)

The `user' table grants privileges that are assigned to you on a global
basis and that apply no matter what the default database is. For
example, if the `user' table grants you the `DELETE' privilege, you can
delete rows from any table in any database on the server host! It is
wise to grant privileges in the `user' table only to people who need
them, such as database administrators. For other users, you should
leave all privileges in the `user' table set to `'N'' and grant
privileges at more specific levels only. You can grant privileges for
particular databases, tables, columns, or routines.

The `db' and `host' tables grant database-specific privileges. Values
in the scope columns of these tables can take the following forms:

   * A blank `User' value in the `db' table matches the anonymous user.
     A nonblank value matches literally; there are no wildcards in user
     names.

   * The wildcard characters ``%'' and ``_'' can be used in the `Host'
     and `Db' columns of either table. These have the same meaning as
     for pattern-matching operations performed with the `LIKE'
     operator. If you want to use either character literally when
     granting privileges, you must escape it with a backslash. For
     example, to include the underscore character (``_'') as part of a
     database name, specify it as ``\_'' in the *Note `GRANT': grant.
     statement.

   * A `'%'' `Host' value in the `db' table means `any host.' A blank
     `Host' value in the `db' table means `consult the `host' table for
     further information' (a process that is described later in this
     section).

   * A `'%'' or blank `Host' value in the `host' table means `any host.'

   * A `'%'' or blank `Db' value in either table means `any database.'

The server reads the `db' and `host' tables into memory and sorts them
at the same time that it reads the `user' table. The server sorts the
`db' table based on the `Host', `Db', and `User' scope columns, and
sorts the `host' table based on the `Host' and `Db' scope columns. As
with the `user' table, sorting puts the most-specific values first and
least-specific values last, and when the server looks for matching
entries, it uses the first match that it finds.

The `tables_priv', `columns_priv', and `procs_priv' tables grant
table-specific, column-specific, and routine-specific privileges.
Values in the scope columns of these tables can take the following
forms:

   * The wildcard characters ``%'' and ``_'' can be used in the `Host'
     column. These have the same meaning as for pattern-matching
     operations performed with the `LIKE' operator.

   * A `'%'' or blank `Host' value means `any host.'

   * The `Db', `Table_name', `Column_name', and `Routine_name' columns
     cannot contain wildcards or be blank.

The server sorts the `tables_priv', `columns_priv', and `procs_priv'
tables based on the `Host', `Db', and `User' columns. This is similar
to `db' table sorting, but simpler because only the `Host' column can
contain wildcards.

The server uses the sorted tables to verify each request that it
receives. For requests that require administrative privileges such as
`SHUTDOWN' or `RELOAD', the server checks only the `user' table row
because that is the only table that specifies administrative
privileges. The server grants access if the row permits the requested
operation and denies access otherwise. For example, if you want to
execute *Note `mysqladmin shutdown': mysqladmin. but your `user' table
row does not grant the `SHUTDOWN' privilege to you, the server denies
access without even checking the `db' or `host' tables. (They contain
no `Shutdown_priv' column, so there is no need to do so.)

For database-related requests (*Note `INSERT': insert, *Note `UPDATE':
update, and so on), the server first checks the user's global
privileges by looking in the `user' table row. If the row permits the
requested operation, access is granted. If the global privileges in the
`user' table are insufficient, the server determines the user's
database-specific privileges by checking the `db' and `host' tables:

  1. The server looks in the `db' table for a match on the `Host', `Db',
     and `User' columns. The `Host' and `User' columns are matched to
     the connecting user's host name and MySQL user name. The `Db'
     column is matched to the database that the user wants to access.
     If there is no row for the `Host' and `User', access is denied.

  2. If there is a matching `db' table row and its `Host' column is not
     blank, that row defines the user's database-specific privileges.

  3. If the matching `db' table row's `Host' column is blank, it
     signifies that the `host' table enumerates which hosts should be
     permitted access to the database. In this case, a further lookup
     is done in the `host' table to find a match on the `Host' and `Db'
     columns. If no `host' table row matches, access is denied. If
     there is a match, the user's database-specific privileges are
     computed as the intersection (_not_ the union!) of the privileges
     in the `db' and `host' table entries; that is, the privileges that
     are `'Y'' in both entries. (This way you can grant general
     privileges in the `db' table row and then selectively restrict
     them on a host-by-host basis using the `host' table entries.)

After determining the database-specific privileges granted by the `db'
and `host' table entries, the server adds them to the global privileges
granted by the `user' table. If the result permits the requested
operation, access is granted. Otherwise, the server successively checks
the user's table and column privileges in the `tables_priv' and
`columns_priv' tables, adds those to the user's privileges, and permits
or denies access based on the result. For stored-routine operations, the
server uses the `procs_priv' table rather than `tables_priv' and
`columns_priv'.

Expressed in boolean terms, the preceding description of how a user's
privileges are calculated may be summarized like this:

     global privileges
     OR (database privileges AND host privileges)
     OR table privileges
     OR column privileges
     OR routine privileges

It may not be apparent why, if the global `user' row privileges are
initially found to be insufficient for the requested operation, the
server adds those privileges to the database, table, and column
privileges later. The reason is that a request might require more than
one type of privilege. For example, if you execute an *Note `INSERT
INTO ... SELECT': insert-select. statement, you need both the `INSERT'
and the `SELECT' privileges. Your privileges might be such that the
`user' table row grants one privilege and the `db' table row grants the
other. In this case, you have the necessary privileges to perform the
request, but the server cannot tell that from either table by itself;
the privileges granted by the entries in both tables must be combined.

The `host' table is not affected by the *Note `GRANT': grant. or *Note
`REVOKE': revoke. statements, so it is unused in most MySQL
installations. If you modify it directly, you can use it for some
specialized purposes, such as to maintain a list of secure servers on
the local network that are granted all privileges.

You can also use the `host' table to indicate hosts that are _not_
secure. Suppose that you have a machine `public.your.domain' that is
located in a public area that you do not consider secure. You can
enable access to all hosts on your network except that machine by using
`host' table entries like this:

     +--------------------+----+-
     | Host               | Db | ...
     +--------------------+----+-
     | public.your.domain | %  | ... (all privileges set to 'N')
     | %.your.domain      | %  | ... (all privileges set to 'Y')
     +--------------------+----+-


File: manual.info,  Node: privilege-changes,  Next: access-denied,  Prev: request-access,  Up: privilege-system

6.4.6 When Privilege Changes Take Effect
----------------------------------------

When *Note `mysqld': mysqld. starts, it reads all grant table contents
into memory. The in-memory tables become effective for access control
at that point.

If you modify the grant tables indirectly using account-management
statements such as *Note `GRANT': grant, *Note `REVOKE': revoke, or
*Note `SET PASSWORD': set-password, the server notices these changes
and loads the grant tables into memory again immediately.

If you modify the grant tables directly using statements such as *Note
`INSERT': insert, *Note `UPDATE': update, or *Note `DELETE': delete,
your changes have no effect on privilege checking until you either
restart the server or tell it to reload the tables. If you change the
grant tables directly but forget to reload them, your changes have _no
effect_ until you restart the server. This may leave you wondering why
your changes do not seem to make any difference!

To tell the server to reload the grant tables, perform a
flush-privileges operation. This can be done by issuing a *Note `FLUSH
PRIVILEGES': flush.  statement or by executing a *Note `mysqladmin
flush-privileges': mysqladmin. or *Note `mysqladmin reload': mysqladmin.
command.

When the server reloads the grant tables, privileges for each existing
client connection are affected as follows:

   * Table and column privilege changes take effect with the client's
     next request.

   * Database privilege changes take effect the next time the client
     executes a `USE DB_NAME' statement.

     *Note*:

     Client applications may cache the database name; thus, this effect
     may not be visible to them without actually changing to a
     different database or flushing the privileges.

   * Global privileges and passwords are unaffected for a connected
     client. These changes take effect only for subsequent connections.

If the server is started with the `--skip-grant-tables' option, it does
not read the grant tables or implement any access control. Anyone can
connect and do anything. To cause a server thus started to read the
tables and enable access checking, flush the privileges.


File: manual.info,  Node: access-denied,  Prev: privilege-changes,  Up: privilege-system

6.4.7 Causes of Access-Denied Errors
------------------------------------

If you encounter problems when you try to connect to the MySQL server,
the following items describe some courses of action you can take to
correct the problem.

   * Make sure that the server is running. If it is not, clients cannot
     connect to it. For example, if an attempt to connect to the server
     fails with a message such as one of those following, one cause
     might be that the server is not running:

          shell> mysql
          ERROR 2003: Can't connect to MySQL server on 'HOST_NAME' (111)
          shell> mysql
          ERROR 2002: Can't connect to local MySQL server through socket
          '/tmp/mysql.sock' (111)

   * It might be that the server is running, but you are trying to
     connect using a TCP/IP port, named pipe, or Unix socket file
     different from the one on which the server is listening. To
     correct this when you invoke a client program, specify a `--port'
     option to indicate the proper port number, or a `--socket' option
     to indicate the proper named pipe or Unix socket file. To find out
     where the socket file is, you can use this command:

          shell> netstat -ln | grep mysql

   * Make sure that the server has not been configured to ignore
     network connections or (if you are attempting to connect remotely)
     that it has not been configured to listen only locally on its
     network interfaces. If the server was started with
     `--skip-networking', it will not accept TCP/IP connections at all.
     If the server was started with `--bind-address=127.0.0.1', it will
     listen for TCP/IP connections only locally on the loopback
     interface and will not accept remote connections.

   * Check to make sure that there is no firewall blocking access to
     MySQL. Your firewall may be configured on the basis of the
     application being executed, or the port number used by MySQL for
     communication (3306 by default). Under Linux or Unix, check your
     IP tables (or similar) configuration to ensure that the port has
     not been blocked. Under Windows, applications such as ZoneAlarm or
     the Windows XP personal firewall may need to be configured not to
     block the MySQL port.

   * The grant tables must be properly set up so that the server can
     use them for access control. For some distribution types (such as
     binary distributions on Windows, or RPM distributions on Linux),
     the installation process initializes the `mysql' database
     containing the grant tables.  For distributions that do not do
     this, you must initialize the grant tables manually by running the
     *Note `mysql_install_db': mysql-install-db. script. For details,
     see *Note unix-postinstallation::.

     To determine whether you need to initialize the grant tables, look
     for a `mysql' directory under the data directory. (The data
     directory normally is named `data' or `var' and is located under
     your MySQL installation directory.) Make sure that you have a file
     named `user.MYD' in the `mysql' database directory. If not,
     execute the *Note `mysql_install_db': mysql-install-db. script.
     After running this script and starting the server, test the initial
     privileges by executing this command:

          shell> mysql -u root test

     The server should let you connect without error.

   * After a fresh installation, you should connect to the server and
     set up your users and their access permissions:

          shell> mysql -u root mysql

     The server should let you connect because the MySQL `root' user
     has no password initially. That is also a security risk, so
     setting the password for the `root' accounts is something you
     should do while you're setting up your other MySQL accounts. For
     instructions on setting the initial passwords, see *Note
     default-privileges::.

   * If you have updated an existing MySQL installation to a newer
     version, did you run the *Note `mysql_upgrade': mysql-upgrade.
     script? If not, do so. The structure of the grant tables changes
     occasionally when new capabilities are added, so after an upgrade
     you should always make sure that your tables have the current
     structure. For instructions, see *Note mysql-upgrade::.

   * If a client program receives the following error message when it
     tries to connect, it means that the server expects passwords in a
     newer format than the client is capable of generating:

          shell> mysql
          Client does not support authentication protocol requested
          by server; consider upgrading MySQL client

     For information on how to deal with this, see *Note
     password-hashing::, and *Note old-client::.

   * Remember that client programs use connection parameters specified
     in option files or environment variables. If a client program
     seems to be sending incorrect default connection parameters when
     you have not specified them on the command line, check any
     applicable option files and your environment. For example, if you
     get `Access denied' when you run a client without any options,
     make sure that you have not specified an old password in any of
     your option files!

     You can suppress the use of option files by a client program by
     invoking it with the `--no-defaults' option. For example:

          shell> mysqladmin --no-defaults -u root version

     The option files that clients use are listed in *Note
     option-files::. Environment variables are listed in *Note
     environment-variables::.

   * If you get the following error, it means that you are using an
     incorrect `root' password:

          shell> mysqladmin -u root -pXXXX ver
          Access denied for user 'root'@'localhost' (using password: YES)

     If the preceding error occurs even when you have not specified a
     password, it means that you have an incorrect password listed in
     some option file. Try the `--no-defaults' option as described in
     the previous item.

     For information on changing passwords, see *Note
     assigning-passwords::.

     If you have lost or forgotten the `root' password, see *Note
     resetting-permissions::.

   * If you change a password by using *Note `SET PASSWORD':
     set-password, *Note `INSERT': insert, or *Note `UPDATE': update,
     you must encrypt the password using the `PASSWORD()' function. If
     you do not use `PASSWORD()' for these statements, the password
     will not work. For example, the following statement assigns a
     password, but fails to encrypt it, so the user is not able to
     connect afterward:

          SET PASSWORD FOR 'abe'@'HOST_NAME' = 'eagle';

     Instead, set the password like this:

          SET PASSWORD FOR 'abe'@'HOST_NAME' = PASSWORD('eagle');

     The `PASSWORD()' function is unnecessary when you specify a
     password using the *Note `GRANT': grant. or (beginning with MySQL
     5.0.2) *Note `CREATE USER': create-user. statements, or the *Note
     `mysqladmin password': mysqladmin. command. Each of those
     automatically uses `PASSWORD()' to encrypt the password. See *Note
     assigning-passwords::, and *Note create-user::.

   * `localhost' is a synonym for your local host name, and is also the
     default host to which clients try to connect if you specify no
     host explicitly.

     To avoid this problem on such systems, you can use a
     `--host=127.0.0.1' option to name the server host explicitly. This
     will make a TCP/IP connection to the local *Note `mysqld': mysqld.
     server. You can also use TCP/IP by specifying a `--host' option
     that uses the actual host name of the local host. In this case,
     the host name must be specified in a `user' table row on the
     server host, even though you are running the client program on the
     same host as the server.

   * The `Access denied' error message tells you who you are trying to
     log in as, the client host from which you are trying to connect,
     and whether you were using a password. Normally, you should have
     one row in the `user' table that exactly matches the host name and
     user name that were given in the error message. For example, if
     you get an error message that contains `using password: NO', it
     means that you tried to log in without a password.

   * If you get an `Access denied' error when trying to connect to the
     database with `mysql -u USER_NAME', you may have a problem with
     the `user' table. Check this by executing `mysql -u root mysql'
     and issuing this SQL statement:

          SELECT * FROM user;

     The result should include a row with the `Host' and `User' columns
     matching your client's host name and your MySQL user name.

   * If the following error occurs when you try to connect from a host
     other than the one on which the MySQL server is running, it means
     that there is no row in the `user' table with a `Host' value that
     matches the client host:

          Host ... is not allowed to connect to this MySQL server

     You can fix this by setting up an account for the combination of
     client host name and user name that you are using when trying to
     connect.

     If you do not know the IP address or host name of the machine from
     which you are connecting, you should put a row with `'%'' as the
     `Host' column value in the `user' table. After trying to connect
     from the client machine, use a `SELECT USER()' query to see how
     you really did connect. Then change the `'%'' in the `user' table
     row to the actual host name that shows up in the log. Otherwise,
     your system is left insecure because it permits connections from
     any host for the given user name.

     On Linux, another reason that this error might occur is that you
     are using a binary MySQL version that is compiled with a different
     version of the `glibc' library than the one you are using. In this
     case, you should either upgrade your operating system or `glibc',
     or download a source distribution of MySQL version and compile it
     yourself. A source RPM is normally trivial to compile and install,
     so this is not a big problem.

   * If you specify a host name when trying to connect, but get an
     error message where the host name is not shown or is an IP
     address, it means that the MySQL server got an error when trying
     to resolve the IP address of the client host to a name:

          shell> mysqladmin -u root -pXXXX -h SOME_HOSTNAME ver
          Access denied for user 'root'@'' (using password: YES)

     If you try to connect as `root' and get the following error, it
     means that you do not have a row in the `user' table with a `User'
     column value of `'root'' and that *Note `mysqld': mysqld. cannot
     resolve the host name for your client:

          Access denied for user ''@'unknown'

     These errors indicate a DNS problem. To fix it, execute *Note
     `mysqladmin flush-hosts': mysqladmin. to reset the internal DNS
     host name cache. See *Note dns::.

     Some permanent solutions are:

        * Determine what is wrong with your DNS server and fix it.

        * Specify IP addresses rather than host names in the MySQL
          grant tables.

        * Put an entry for the client machine name in `/etc/hosts' on
          Unix or `\windows\hosts' on Windows.

        * Start *Note `mysqld': mysqld. with the `--skip-name-resolve'
          option.

        * Start *Note `mysqld': mysqld. with the `--skip-host-cache'
          option.

        * On Unix, if you are running the server and the client on the
          same machine, connect to `localhost'.  Unix connections to
          `localhost' use a Unix socket file rather than TCP/IP.

        * On Windows, if you are running the server and the client on
          the same machine and the server supports named pipe
          connections, connect to the host name `.' (period).
          Connections to `.' use a named pipe rather than TCP/IP.

   * If `mysql -u root test' works but `mysql -h YOUR_HOSTNAME -u root
     test' results in `Access denied' (where YOUR_HOSTNAME is the
     actual host name of the local host), you may not have the correct
     name for your host in the `user' table. A common problem here is
     that the `Host' value in the `user' table row specifies an
     unqualified host name, but your system's name resolution routines
     return a fully qualified domain name (or vice versa). For example,
     if you have an entry with host `'pluto'' in the `user' table, but
     your DNS tells MySQL that your host name is `'pluto.example.com'',
     the entry does not work. Try adding an entry to the `user' table
     that contains the IP address of your host as the `Host' column
     value.  (Alternatively, you could add an entry to the `user' table
     with a `Host' value that contains a wildcard; for example,
     `'pluto.%''. However, use of `Host' values ending with ``%'' is
     _insecure_ and is _not_ recommended!)

   * If `mysql -u USER_NAME test' works but `mysql -u USER_NAME
     OTHER_DB' does not, you have not granted access to the given user
     for the database named OTHER_DB.

   * If `mysql -u USER_NAME' works when executed on the server host,
     but `mysql -h HOST_NAME -u USER_NAME' does not work when executed
     on a remote client host, you have not enabled access to the server
     for the given user name from the remote host.

   * If you cannot figure out why you get `Access denied', remove from
     the `user' table all entries that have `Host' values containing
     wildcards (entries that contain `'%'' or `'_'' characters).  A
     very common error is to insert a new entry with `Host'=`'%'' and
     `User'=`'SOME_USER'', thinking that this enables you to specify
     `localhost' to connect from the same machine.  The reason that
     this does not work is that the default privileges include an entry
     with `Host'=`'localhost'' and `User'=`'''. Because that entry has
     a `Host' value `'localhost'' that is more specific than `'%'', it
     is used in preference to the new entry when connecting from
     `localhost'! The correct procedure is to insert a second entry with
     `Host'=`'localhost'' and `User'=`'SOME_USER'', or to delete the
     entry with `Host'=`'localhost'' and `User'=`'''. After deleting
     the entry, remember to issue a *Note `FLUSH PRIVILEGES': flush.
     statement to reload the grant tables. See also *Note
     connection-access::.

   * If you are able to connect to the MySQL server, but get an `Access
     denied' message whenever you issue a *Note `SELECT ... INTO
     OUTFILE': select-into. or *Note `LOAD DATA INFILE': load-data.
     statement, your entry in the `user' table does not have the `FILE'
     privilege enabled.

   * If you change the grant tables directly (for example, by using
     *Note `INSERT': insert, *Note `UPDATE': update, or *Note `DELETE':
     delete. statements) and your changes seem to be ignored, remember
     that you must execute a *Note `FLUSH PRIVILEGES': flush. statement
     or a *Note `mysqladmin flush-privileges': mysqladmin. command to
     cause the server to reload the privilege tables. Otherwise, your
     changes have no effect until the next time the server is
     restarted. Remember that after you change the `root' password with
     an *Note `UPDATE': update. statement, you will not need to specify
     the new password until after you flush the privileges, because the
     server will not know you've changed the password yet!

   * If your privileges seem to have changed in the middle of a
     session, it may be that a MySQL administrator has changed them.
     Reloading the grant tables affects new client connections, but it
     also affects existing connections as indicated in *Note
     privilege-changes::.

   * If you have access problems with a Perl, PHP, Python, or ODBC
     program, try to connect to the server with `mysql -u USER_NAME
     DB_NAME' or `mysql -u USER_NAME -pYOUR_PASS DB_NAME'. If you are
     able to connect using the *Note `mysql': mysql. client, the
     problem lies with your program, not with the access privileges.
     (There is no space between `-p' and the password; you can also use
     the `--password=YOUR_PASS' syntax to specify the password. If you
     use the `-p' or `--password' option with no password value, MySQL
     prompts you for the password.)

   * For testing purposes, start the *Note `mysqld': mysqld.  server
     with the `--skip-grant-tables' option.  Then you can change the
     MySQL grant tables and use the *Note `mysqlaccess': mysqlaccess.
     script to check whether your modifications have the desired
     effect. When you are satisfied with your changes, execute *Note
     `mysqladmin flush-privileges': mysqladmin. to tell the *Note
     `mysqld': mysqld. server to reload the privileges.  This enables
     you to begin using the new grant table contents without stopping
     and restarting the server.

   * If you get the following error, you may have a problem with the
     `db' or `host' table:

          Access to database denied

     If the entry selected from the `db' table has an empty value in
     the `Host' column, make sure that there are one or more
     corresponding entries in the `host' table specifying which hosts
     the `db' table entry applies to. This problem occurs infrequently
     because the `host' table is rarely used.

   * If everything else fails, start the *Note `mysqld': mysqld.
     server with a debugging option (for example,
     `--debug=d,general,query'). This prints host and user information
     about attempted connections, as well as information about each
     command issued. See MySQL Internals: Porting
     (http://forge.mysql.com/wiki/MySQL_Internals_Porting).

   * If you have any other problems with the MySQL grant tables and
     feel you must post the problem to the mailing list, always provide
     a dump of the MySQL grant tables. You can dump the tables with the
     *Note `mysqldump mysql': mysqldump. command. To file a bug report,
     see the instructions at *Note bug-reports::. In some cases, you
     may need to restart *Note `mysqld': mysqld. with
     `--skip-grant-tables' to run *Note `mysqldump': mysqldump.


File: manual.info,  Node: user-account-management,  Next: multiple-servers,  Prev: privilege-system,  Up: server-administration

6.5 MySQL User Account Management
=================================

* Menu:

* user-names::                   User Names and Passwords
* adding-users::                 Adding User Accounts
* removing-users::               Removing User Accounts
* user-resources::               Setting Account Resource Limits
* assigning-passwords::          Assigning Account Passwords
* secure-connections::           Using SSL for Secure Connections
* windows-and-ssh::              Connecting to MySQL Remotely from Windows with SSH
* account-activity-auditing::    Auditing MySQL Account Activity

This section describes how to set up accounts for clients of your MySQL
server. It discusses the following topics:

   * The meaning of account names and passwords as used in MySQL and
     how that compares to names and passwords used by your operating
     system

   * How to set up new accounts and remove existing accounts

   * How to change passwords

   * Guidelines for using passwords securely

   * How to use secure connections with SSL

See also *Note account-management-sql::, which describes the syntax and
use for all user-management SQL statements.


File: manual.info,  Node: user-names,  Next: adding-users,  Prev: user-account-management,  Up: user-account-management

6.5.1 User Names and Passwords
------------------------------

MySQL stores accounts in the `user' table of the `mysql' database. An
account is defined in terms of a user name and the client host or hosts
from which the user can connect to the server. The account may also
have a password.  For information about account representation in the
`user' table, see *Note grant-table-structure::.

There are several distinctions between the way user names and passwords
are used by MySQL and the way they are used by your operating system:

   * User names, as used by MySQL for authentication purposes, have
     nothing to do with user names (login names) as used by Windows or
     Unix. On Unix, most MySQL clients by default try to log in using
     the current Unix user name as the MySQL user name, but that is for
     convenience only. The default can be overridden easily, because
     client programs permit any user name to be specified with a `-u' or
     `--user' option. Because this means that anyone can attempt to
     connect to the server using any user name, you cannot make a
     database secure in any way unless all MySQL accounts have
     passwords. Anyone who specifies a user name for an account that
     has no password is able to connect successfully to the server.

   * MySQL user names can be up to 16 characters long. Operating system
     user names, because they are completely unrelated to MySQL user
     names, may be of a different maximum length. For example, Unix
     user names typically are limited to eight characters.

     *Warning*:

     The limit on MySQL user name length is hard-coded in the MySQL
     servers and clients, and trying to circumvent it by modifying the
     definitions of the tables in the `mysql' database _does not work_.

     You should never alter any of the tables in the `mysql' database
     in any manner whatsoever except by means of the procedure that is
     described in *Note mysql-upgrade::. Attempting to redefine MySQL's
     system tables in any other fashion results in undefined (and
     unsupported!) behavior.

   * The server uses MySQL passwords stored in the `user' table to
     authenticate client connections using MySQL built-in
     authentication. These passwords have nothing to do with passwords
     for logging in to your operating system. There is no necessary
     connection between the `external' password you use to log in to a
     Windows or Unix machine and the password you use to access the
     MySQL server on that machine.

   * MySQL encrypts passwords stored in the `user' table using its own
     algorithm. This encryption is the same as that implemented by the
     `PASSWORD()' SQL function but differs from that used during the
     Unix login process. Unix password encryption is the same as that
     implemented by the `ENCRYPT()' SQL function. See the descriptions
     of the `PASSWORD()' and `ENCRYPT()' functions in *Note
     encryption-functions::.

     From version 4.1 on, MySQL employs a stronger authentication
     method that has better password protection during the connection
     process than in earlier versions. It is secure even if TCP/IP
     packets are sniffed or the `mysql' database is captured. (In
     earlier versions, even though passwords are stored in encrypted
     form in the `user' table, knowledge of the encrypted password
     value could be used to connect to the MySQL server.)  *Note
     password-hashing::, discusses password encryption further.

   * It is possible to connect to the server regardless of character
     set settings if the user name and password contain only ASCII
     characters. To connect when the user name or password contain
     non-ASCII characters, the client should call the `mysql_options()'
     C API function with the `MYSQL_SET_CHARSET_NAME' option and
     appropriate character set name as arguments. This causes
     authentication to take place using the specified character set.
     Otherwise, authentication will fail unless the server default
     character set is the same as the encoding in the authentication
     defaults.

     Standard MySQL client programs support a `--default-character-set'
     option that causes `mysql_options()' to be called as just
     described. For programs that use a connector that is not based on
     the C API, the connector may provide an equivalent to
     `mysql_options()' that can be used instead. Check the connector
     documentation.

     The preceding notes do not apply for `ucs2', which is not
     permitted as a client character set.

When you install MySQL, the grant tables are populated with an initial
set of accounts. The names and access privileges for these accounts are
described in *Note default-privileges::, which also discusses how to
assign passwords to them. Thereafter, you normally set up, modify, and
remove MySQL accounts using statements such as *Note `CREATE USER':
create-user, *Note `GRANT': grant, and *Note `REVOKE': revoke. See
*Note account-management-sql::.

When you connect to a MySQL server with a command-line client, specify
the user name and password as necessary for the account that you want
to use:

     shell> mysql --user=monty --password=PASSWORD DB_NAME

If you prefer short options, the command looks like this:

     shell> mysql -u monty -pPASSWORD DB_NAME

There must be _no space_ between the `-p' option and the following
password value.

If you omit the PASSWORD value following the `--password' or `-p'
option on the command line, the client prompts for one.

Specifying a password on the command line should be considered
insecure. See *Note password-security-user::. You can use an option
file to avoid giving the password on the command line.

For additional information about specifying user names, passwords, and
other connection parameters, see *Note connecting::.


File: manual.info,  Node: adding-users,  Next: removing-users,  Prev: user-names,  Up: user-account-management

6.5.2 Adding User Accounts
--------------------------

You can create MySQL accounts in two ways:

   * By using statements intended for creating accounts, such as *Note
     `CREATE USER': create-user. or *Note `GRANT': grant. These
     statements cause the server to make appropriate modifications to
     the grant tables.

   * By manipulating the MySQL grant tables directly with statements
     such as *Note `INSERT': insert, *Note `UPDATE': update, or *Note
     `DELETE': delete.

The preferred method is to use account-creation statements because they
are more concise and less error-prone than manipulating the grant
tables directly. *Note `CREATE USER': create-user.  and *Note `GRANT':
grant. are described in *Note account-management-sql::.

Another option for creating accounts is to use one of several available
third-party programs that offer capabilities for MySQL account
administration. `phpMyAdmin' is one such program.

The following examples show how to use the *Note `mysql': mysql. client
program to set up new accounts.  These examples assume that privileges
have been set up according to the defaults described in *Note
default-privileges::.  This means that to make changes, you must
connect to the MySQL server as the MySQL `root' user, and the `root'
account must have the `INSERT' privilege for the `mysql' database and
the `RELOAD' administrative privilege.

As noted in the examples where appropriate, some of the statements will
fail if the server's SQL mode has been set to enable certain
restrictions. In particular, strict mode (`STRICT_TRANS_TABLES',
`STRICT_ALL_TABLES') and `NO_AUTO_CREATE_USER' will prevent the server
from accepting some of the statements. Workarounds are indicated for
these cases. For more information about SQL modes and their effect on
grant table manipulation, see *Note server-sql-mode::, and *Note
grant::.

First, use the *Note `mysql': mysql. program to connect to the server
as the MySQL `root' user:

     shell> mysql --user=root mysql

If you have assigned a password to the `root' account, you will also
need to supply a `--password' or `-p' option, both for this *Note
`mysql': mysql. command and for those later in this section.

After connecting to the server as `root', you can add new accounts. The
following statements use *Note `GRANT': grant. to set up four new
accounts:

     mysql> CREATE USER 'monty'@'localhost' IDENTIFIED BY 'some_pass';
     mysql> GRANT ALL PRIVILEGES ON *.* TO 'monty'@'localhost'
         ->     WITH GRANT OPTION;
     mysql> CREATE USER 'monty'@'%' IDENTIFIED BY 'some_pass';
     mysql> GRANT ALL PRIVILEGES ON *.* TO 'monty'@'%'
         ->     WITH GRANT OPTION;
     mysql> CREATE USER 'admin'@'localhost';
     mysql> GRANT RELOAD,PROCESS ON *.* TO 'admin'@'localhost';
     mysql> CREATE USER 'dummy'@'localhost';

The accounts created by these statements have the following properties:

   * Two of the accounts have a user name of `monty' and a password of
     `some_pass'. Both accounts are superuser accounts with full
     privileges to do anything. The `'monty'@'localhost'' account can
     be used only when connecting from the local host. The
     `'monty'@'%'' account uses the `'%'' wildcard for the host part,
     so it can be used to connect from any host.

     It is necessary to have both accounts for `monty' to be able to
     connect from anywhere as `monty'. Without the `localhost' account,
     the anonymous-user account for `localhost' that is created by
     *Note `mysql_install_db': mysql-install-db. would take precedence
     when `monty' connects from the local host. As a result, `monty'
     would be treated as an anonymous user. The reason for this is that
     the anonymous-user account has a more specific `Host' column value
     than the `'monty'@'%'' account and thus comes earlier in the
     `user' table sort order.  (`user' table sorting is discussed in
     *Note connection-access::.)

   * The `'admin'@'localhost'' account has no password. This account
     can be used only by `admin' to connect from the local host. It is
     granted the `RELOAD' and `PROCESS' administrative privileges.
     These privileges enable the `admin' user to execute the *Note
     `mysqladmin reload': mysqladmin, *Note `mysqladmin refresh':
     mysqladmin, and *Note `mysqladmin flush-XXX': mysqladmin.
     commands, as well as *Note `mysqladmin processlist': mysqladmin .
     No privileges are granted for accessing any databases. You could
     add such privileges later by issuing other *Note `GRANT': grant.
     statements.

   * The `'dummy'@'localhost'' account has no password. This account
     can be used only to connect from the local host. No privileges are
     granted. It is assumed that you will grant specific privileges to
     the account later.

The statements that create accounts with no password will fail if the
`NO_AUTO_CREATE_USER' SQL mode is enabled. To deal with this, use an
`IDENTIFIED BY' clause that specifies a nonempty password.

To check the privileges for an account, use *Note `SHOW GRANTS':
show-grants.:

     mysql> SHOW GRANTS FOR 'admin'@'localhost';
     +-----------------------------------------------------+
     | Grants for admin@localhost                          |
     +-----------------------------------------------------+
     | GRANT RELOAD, PROCESS ON *.* TO 'admin'@'localhost' |
     +-----------------------------------------------------+

As an alternative to *Note `CREATE USER': create-user.  and *Note
`GRANT': grant, you can create the same accounts directly by issuing
*Note `INSERT': insert.  statements and then telling the server to
reload the grant tables using *Note `FLUSH PRIVILEGES': flush.:

     shell> mysql --user=root mysql
     mysql> INSERT INTO user
         ->     VALUES('localhost','monty',PASSWORD('some_pass'),
         ->     'Y','Y','Y','Y','Y','Y','Y','Y','Y','Y','Y','Y','Y','Y');
     mysql> INSERT INTO user
         ->     VALUES('%','monty',PASSWORD('some_pass'),
         ->     'Y','Y','Y','Y','Y','Y','Y','Y','Y','Y','Y','Y','Y',
         ->     'Y','Y','Y','Y','Y','Y','Y','Y','Y','Y','Y','Y','Y',
         ->     '','','','',0,0,0,0);
     mysql> INSERT INTO user SET Host='localhost',User='admin',
         ->     Reload_priv='Y', Process_priv='Y';
     mysql> INSERT INTO user (Host,User,Password)
         ->     VALUES('localhost','dummy','');
     mysql> FLUSH PRIVILEGES;

When you create accounts with *Note `INSERT': insert, it is necessary
to use *Note `FLUSH PRIVILEGES': flush.  to tell the server to reload
the grant tables. Otherwise, the changes go unnoticed until you restart
the server. With *Note `CREATE USER': create-user, *Note `FLUSH
PRIVILEGES': flush.  is unnecessary.

The reason for using the `PASSWORD()' function with *Note `INSERT':
insert. is to encrypt the password. The *Note `CREATE USER':
create-user.  statement encrypts the password for you, so `PASSWORD()'
is unnecessary.

The `'Y'' values enable privileges for the accounts. Depending on your
MySQL version, you may have to use a different number of `'Y'' values
in the first two *Note `INSERT': insert. statements. The *Note
`INSERT': insert. statement for the `admin' account employs the more
readable extended *Note `INSERT': insert. syntax using `SET'.

In the *Note `INSERT': insert. statement for the `dummy' account, only
the `Host', `User', and `Password' columns in the `user' table row are
assigned values. None of the privilege columns are set explicitly, so
MySQL assigns them all the default value of `'N''. This is equivalent
to what *Note `CREATE USER': create-user. does.

If strict SQL mode is enabled, all columns that have no default value
must have a value specified. In this case, *Note `INSERT': insert.
statements must explicitly specify values for the `ssl_cipher',
`x509_issuer', and `x509_subject' columns.

To set up a superuser account, it is necessary only to insert a `user'
table row with all privilege columns set to `'Y''. The `user' table
privileges are global, so no entries in any of the other grant tables
are needed.

The next examples create three accounts and give them access to
specific databases. Each of them has a user name of `custom' and
password of `obscure'.

To create the accounts with *Note `CREATE USER': create-user. and *Note
`GRANT': grant, use the following statements:

     shell> mysql --user=root mysql
     mysql> CREATE USER 'custom'@'localhost' IDENTIFIED BY 'obscure';
     mysql> GRANT SELECT,INSERT,UPDATE,DELETE,CREATE,DROP
         ->     ON bankaccount.*
         ->     TO 'custom'@'localhost';
     mysql> CREATE USER 'custom'@'host47.example.com' IDENTIFIED BY 'obscure';
     mysql> GRANT SELECT,INSERT,UPDATE,DELETE,CREATE,DROP
         ->     ON expenses.*
         ->     TO 'custom'@'host47.example.com';
     mysql> CREATE USER 'custom'@'server.domain' IDENTIFIED BY 'obscure';
     mysql> GRANT SELECT,INSERT,UPDATE,DELETE,CREATE,DROP
         ->     ON customer.*
         ->     TO 'custom'@'server.domain';

The three accounts can be used as follows:

   * The first account can access the `bankaccount' database, but only
     from the local host.

   * The second account can access the `expenses' database, but only
     from the host `host47.example.com'.

   * The third account can access the `customer' database, but only
     from the host `server.domain'.

To set up the `custom' accounts without *Note `GRANT': grant, use *Note
`INSERT': insert. statements as follows to modify the grant tables
directly:

     shell> mysql --user=root mysql
     mysql> INSERT INTO user (Host,User,Password)
         ->     VALUES('localhost','custom',PASSWORD('obscure'));
     mysql> INSERT INTO user (Host,User,Password)
         ->     VALUES('host47.example.com','custom',PASSWORD('obscure'));
     mysql> INSERT INTO user (Host,User,Password)
         ->     VALUES('server.domain','custom',PASSWORD('obscure'));
     mysql> INSERT INTO db
         ->     (Host,Db,User,Select_priv,Insert_priv,
         ->     Update_priv,Delete_priv,Create_priv,Drop_priv)
         ->     VALUES('localhost','bankaccount','custom',
         ->     'Y','Y','Y','Y','Y','Y');
     mysql> INSERT INTO db
         ->     (Host,Db,User,Select_priv,Insert_priv,
         ->     Update_priv,Delete_priv,Create_priv,Drop_priv)
         ->     VALUES('host47.example.com','expenses','custom',
         ->     'Y','Y','Y','Y','Y','Y');
     mysql> INSERT INTO db
         ->     (Host,Db,User,Select_priv,Insert_priv,
         ->     Update_priv,Delete_priv,Create_priv,Drop_priv)
         ->     VALUES('server.domain','customer','custom',
         ->     'Y','Y','Y','Y','Y','Y');
     mysql> FLUSH PRIVILEGES;

The first three *Note `INSERT': insert. statements add `user' table
entries that permit the user `custom' to connect from the various hosts
with the given password, but grant no global privileges (all privileges
are set to the default value of `'N''). The next three *Note `INSERT':
insert. statements add `db' table entries that grant privileges to
`custom' for the `bankaccount', `expenses', and `customer' databases,
but only when accessed from the proper hosts. As usual when you modify
the grant tables directly, you must tell the server to reload them with
*Note `FLUSH PRIVILEGES': flush.  so that the privilege changes take
effect.

To create a user who has access from all machines in a given domain
(for example, `mydomain.com'), you can use the ``%'' wildcard character
in the host part of the account name:

     mysql> CREATE USER 'myname'@'%.mydomain.com' IDENTIFIED BY 'mypass';

To do the same thing by modifying the grant tables directly, do this:

     mysql> INSERT INTO user (Host,User,Password,...)
         ->     VALUES('%.mydomain.com','myname',PASSWORD('mypass'),...);
     mysql> FLUSH PRIVILEGES;


File: manual.info,  Node: removing-users,  Next: user-resources,  Prev: adding-users,  Up: user-account-management

6.5.3 Removing User Accounts
----------------------------

To remove an account, use the *Note `DROP USER': drop-user. statement,
which is described in *Note drop-user::.


File: manual.info,  Node: user-resources,  Next: assigning-passwords,  Prev: removing-users,  Up: user-account-management

6.5.4 Setting Account Resource Limits
-------------------------------------

One means of limiting use of MySQL server resources is to set the
global `max_user_connections' system variable to a nonzero value. This
limits the number of simultaneous connections that can be made by any
given account, but places no limits on what a client can do once
connected. In addition, setting `max_user_connections' does not enable
management of individual accounts. Both types of control are of
interest to many MySQL administrators, particularly those working for
Internet Service Providers.

In MySQL 5.0, you can limit use of the following server resources for
individual accounts:

   * The number of queries that an account can issue per hour

   * The number of updates that an account can issue per hour

   * The number of times an account can connect to the server per hour

   * The number of simultaneous connections to the server by an account
     (available as of MySQL 5.0.3)

Any statement that a client can issue counts against the query limit
(unless its results are served from the query cache). Only statements
that modify databases or tables count against the update limit.

An `account' in this context corresponds to a row in the `mysql.user'
table. That is, a connection is assessed against the `User' and `Host'
values in the `user' table row that applies to the connection. For
example, an account `'usera'@'%.example.com'' corresponds to a row in
the `user' table that has `User' and `Host' values of `usera' and
`%.example.com', to permit `usera' to connect from any host in the
`example.com' domain. In this case, the server applies resource limits
in this row collectively to all connections by `usera' from any host in
the `example.com' domain because all such connections use the same
account.

Before MySQL 5.0.3, an `account' was assessed against the actual host
from which a user connects. This older method accounting may be
selected by starting the server with the `--old-style-user-limits'
option. In this case, if `usera' connects simultaneously from
`host1.example.com' and `host2.example.com', the server applies the
account resource limits separately to each connection. If `usera'
connects again from `host1.example.com', the server applies the limits
for that connection together with the existing connection from that
host.

To set resource limits for an account, use the *Note `GRANT': grant.
statement (see *Note grant::). Provide a `WITH' clause that names each
resource to be limited. The default value for each limit is zero (no
limit). For example, to create a new account that can access the
`customer' database, but only in a limited fashion, issue these
statements:

     mysql> CREATE USER 'francis'@'localhost' IDENTIFIED BY 'frank';
     mysql> GRANT ALL ON customer.* TO 'francis'@'localhost'
         ->     WITH MAX_QUERIES_PER_HOUR 20
         ->          MAX_UPDATES_PER_HOUR 10
         ->          MAX_CONNECTIONS_PER_HOUR 5
         ->          MAX_USER_CONNECTIONS 2;

The limit types need not all be named in the `WITH' clause, but those
named can be present in any order. The value for each per-hour limit
should be an integer representing a count per hour. For
`MAX_USER_CONNECTIONS', the limit is an integer representing the
maximum number of simultaneous connections by the account. If this
limit is set to zero, the global `max_user_connections' system variable
value determines the number of simultaneous connections.  If
`max_user_connections' is also zero, there is no limit for the account.

To modify existing limits for an account, use a *Note `GRANT USAGE':
grant.  statement at the global level (`ON *.*'). The following
statement changes the query limit for `francis' to 100:

     mysql> GRANT USAGE ON *.* TO 'francis'@'localhost'
         ->     WITH MAX_QUERIES_PER_HOUR 100;

The statement modifies only the limit value specified and leaves the
account otherwise unchanged.

To remove a limit, set its value to zero. For example, to remove the
limit on how many times per hour `francis' can connect, use this
statement:

     mysql> GRANT USAGE ON *.* TO 'francis'@'localhost'
         ->     WITH MAX_CONNECTIONS_PER_HOUR 0;

As mentioned previously, the simultaneous-connection limit for an
account is determined from the `MAX_USER_CONNECTIONS' limit and the
`max_user_connections' system variable. Suppose that the global
`max_user_connections' value is 10 and three accounts have resource
limits specified with *Note `GRANT': grant.:

     GRANT ... TO 'user1'@'localhost' WITH MAX_USER_CONNECTIONS 0;
     GRANT ... TO 'user2'@'localhost' WITH MAX_USER_CONNECTIONS 5;
     GRANT ... TO 'user3'@'localhost' WITH MAX_USER_CONNECTIONS 20;

`user1' has a connection limit of 10 (the global `max_user_connections'
value) because it has a zero `MAX_USER_CONNECTIONS' limit). `user2' and
`user3' have connection limits of 5 and 20, respectively, because they
have nonzero `MAX_USER_CONNECTIONS' limits.

The server stores resource limits for an account in the `user' table
row corresponding to the account.  The `max_questions', `max_updates',
and `max_connections' columns store the per-hour limits, and the
`max_user_connections' column stores the `MAX_USER_CONNECTIONS' limit.
(See *Note grant-table-structure::.) If your `user' table does not have
these columns, it must be upgraded; see *Note mysql-upgrade::.

Resource-use counting takes place when any account has a nonzero limit
placed on its use of any of the resources.

As the server runs, it counts the number of times each account uses
resources. If an account reaches its limit on number of connections
within the last hour, further connections for the account are rejected
until that hour is up. Similarly, if the account reaches its limit on
the number of queries or updates, further queries or updates are
rejected until the hour is up. In all such cases, an appropriate error
message is issued.

Resource counting is done per account, not per client. For example, if
your account has a query limit of 50, you cannot increase your limit to
100 by making two simultaneous client connections to the server.
Queries issued on both connections are counted together.

The current per-hour resource-use counts can be reset globally for all
accounts, or individually for a given account:

   * To reset the current counts to zero for all accounts, issue a
     *Note `FLUSH USER_RESOURCES': flush. statement. The counts also
     can be reset by reloading the grant tables (for example, with a
     *Note `FLUSH PRIVILEGES': flush. statement or a *Note `mysqladmin
     reload': mysqladmin. command).

   * The counts for an individual account can be set to zero by
     re-granting it any of its limits. To do this, use *Note `GRANT
     USAGE': grant.  as described earlier and specify a limit value
     equal to the value that the account currently has.

Counter resets do not affect the `MAX_USER_CONNECTIONS' limit.

All counts begin at zero when the server starts; counts are not carried
over through a restart.

For the `MAX_USER_CONNECTIONS' limit, an edge case can occur if the
account currently has open the maximum number of connections permitted
to it: A disconnect followed quickly by a connect can result in an error
(`ER_TOO_MANY_USER_CONNECTIONS' or `ER_USER_LIMIT_REACHED') if the
server has not fully processed the disconnect by the time the connect
occurs. When the server finishes disconnect processing, another
connection will once more be permitted.


File: manual.info,  Node: assigning-passwords,  Next: secure-connections,  Prev: user-resources,  Up: user-account-management

6.5.5 Assigning Account Passwords
---------------------------------

Required credentials for clients that connect to the MySQL server can
include a password. This section describes how to assign passwords for
MySQL accounts.

To assign a password when you create a new account with *Note `CREATE
USER': create-user, include an `IDENTIFIED BY' clause:

     mysql> CREATE USER 'jeffrey'@'localhost'
         -> IDENTIFIED BY 'mypass';

To assign or change a password for an existing account, one way is to
issue a *Note `SET PASSWORD': set-password. statement:

     mysql> SET PASSWORD FOR
         -> 'jeffrey'@'localhost' = PASSWORD('mypass');

MySQL stores passwords in the `user' table in the `mysql' database.
Only users such as `root' that have update access to the `mysql'
database can change the password for other users. If you are not
connected as an anonymous user, you can change your own password by
omitting the `FOR' clause:

     mysql> SET PASSWORD = PASSWORD('mypass');

You can also use a *Note `GRANT USAGE': grant. statement at the global
level (`ON *.*') to assign a password to an account without affecting
the account's current privileges:

     mysql> GRANT USAGE ON *.* TO 'jeffrey'@'localhost'
         -> IDENTIFIED BY 'mypass';

To assign a password from the command line, use the *Note `mysqladmin':
mysqladmin. command:

     shell> mysqladmin -u USER_NAME -h HOST_NAME password "NEWPWD"

The account for which this command sets the password is the one with a
`user' table row that matches USER_NAME in the `User' column and the
client host _from which you connect_ in the `Host' column.

It is preferable to assign passwords using one of the preceding
methods, but it is also possible to modify the `user' table directly.
In this case, you must also use *Note `FLUSH PRIVILEGES': flush. to
cause the server to reread the grant tables. Otherwise, the change
remains unnoticed by the server until you restart it.

   * To establish a password for a new account, provide a value for the
     `Password' column:

          mysql> INSERT INTO mysql.user (Host,User,Password)
              -> VALUES('localhost','jeffrey',PASSWORD('mypass'));
          mysql> FLUSH PRIVILEGES;

   * To change the password for an existing account, use *Note
     `UPDATE': update. to set the `Password' column value:

          mysql> UPDATE mysql.user SET Password = PASSWORD('bagel')
              -> WHERE Host = 'localhost' AND User = 'francis';
          mysql> FLUSH PRIVILEGES;

During authentication when a client connects to the server, MySQL
treats the password in the `user' table as an encrypted hash value (the
value that `PASSWORD()' would return for the password). When assigning
a password to an account, it is important to store an encrypted value,
not the plaintext password.  Use the following guidelines:

   * When you assign a password using *Note `CREATE USER': create-user,
     *Note `GRANT': grant. with an `IDENTIFIED BY' clause, or the *Note
     `mysqladmin password': mysqladmin. command, they encrypt the
     password for you. Specify the literal plaintext password:

          mysql> CREATE USER 'jeffrey'@'localhost'
              -> IDENTIFIED BY 'mypass';

   * For *Note `CREATE USER': create-user. or *Note `GRANT': grant, you
     can avoid sending the plaintext password if you know the hash
     value that `PASSWORD()' would return for the password. Specify the
     hash value preceded by the keyword `PASSWORD':

          mysql> CREATE USER 'jeffrey'@'localhost'
              -> IDENTIFIED BY PASSWORD '*90E462C37378CED12064BB3388827D2BA3A9B689';

   * When you assign an account a nonempty password using *Note `SET
     PASSWORD': set-password, *Note `INSERT': insert, or *Note
     `UPDATE': update, you must use the `PASSWORD()' function to encrypt
     the password, otherwise the password is stored as plaintext.
     Suppose that you assign a password like this:

          mysql> SET PASSWORD FOR
              -> 'jeffrey'@'localhost' = 'mypass';

     The result is that the literal value `'mypass'' is stored as the
     password in the `user' table, not the encrypted value. When
     `jeffrey' attempts to connect to the server using this password,
     the value is encrypted and compared to the value stored in the
     `user' table.  However, the stored value is the literal string
     `'mypass'', so the comparison fails and the server rejects the
     connection with an `Access denied' error.

*Note*:

`PASSWORD()' encryption differs from Unix password encryption. See
*Note user-names::.


File: manual.info,  Node: secure-connections,  Next: windows-and-ssh,  Prev: assigning-passwords,  Up: user-account-management

6.5.6 Using SSL for Secure Connections
--------------------------------------

* Menu:

* secure-basics::                Basic SSL Concepts
* secure-using-ssl::             Using SSL Connections
* ssl-options::                  SSL Command Options
* secure-create-certs::          Setting Up SSL Certificates for MySQL

MySQL supports secure (encrypted) connections between MySQL clients and
the server using the Secure Sockets Layer (SSL) protocol. This section
discusses how to use SSL connections. For information on how to require
users to use SSL connections, see the discussion of the `REQUIRE'
clause of the *Note `GRANT': grant. statement in *Note grant::.

The standard configuration of MySQL is intended to be as fast as
possible, so encrypted connections are not used by default. For
applications that require the security provided by encrypted
connections, the extra computation to encrypt the data is worthwhile.

MySQL enables encryption on a per-connection basis. You can choose a
normal unencrypted connection or a secure encrypted SSL connection
according the requirements of individual applications.

Secure connections are based on the OpenSSL API and are available
through the MySQL C API. Replication uses the C API, so secure
connections can be used between master and slave servers.

Another way to connect securely is from within an SSH connection to the
MySQL server host. For an example, see *Note windows-and-ssh::.


File: manual.info,  Node: secure-basics,  Next: secure-using-ssl,  Prev: secure-connections,  Up: secure-connections

6.5.6.1 Basic SSL Concepts
..........................

To understand how MySQL uses SSL, it is necessary to explain some basic
SSL and X509 concepts. People who are familiar with these can skip this
part of the discussion.

By default, MySQL uses unencrypted connections between the client and
the server. This means that someone with access to the network could
watch all your traffic and look at the data being sent or received.
They could even change the data while it is in transit between client
and server. To improve security a little, you can compress
client/server traffic by using the `--compress' option when invoking
client programs. However, this does not foil a determined attacker.

When you need to move information over a network in a secure fashion,
an unencrypted connection is unacceptable. Encryption is the way to
make any kind of data unreadable. In fact, today's practice requires
many additional security elements from encryption algorithms. They
should resist many kind of known attacks such as changing the order of
encrypted messages or replaying data twice.

SSL is a protocol that uses different encryption algorithms to ensure
that data received over a public network can be trusted.  It has
mechanisms to detect any data change, loss, or replay.  SSL also
incorporates algorithms that provide identity verification using the
X509 standard.

X509 makes it possible to identify someone on the Internet. It is most
commonly used in e-commerce applications. In basic terms, there should
be some company called a `Certificate Authority' (or CA) that assigns
electronic certificates to anyone who needs them. Certificates rely on
asymmetric encryption algorithms that have two encryption keys (a public
key and a secret key). A certificate owner can show the certificate to
another party as proof of identity. A certificate consists of its
owner's public key. Any data encrypted with this public key can be
decrypted only using the corresponding secret key, which is held by the
owner of the certificate.

If you need more information about SSL, X509, or encryption, use your
favorite Internet search engine to search for the keywords in which you
are interested.


File: manual.info,  Node: secure-using-ssl,  Next: ssl-options,  Prev: secure-basics,  Up: secure-connections

6.5.6.2 Using SSL Connections
.............................

To use SSL connections between the MySQL server and client programs,
your system must support either OpenSSL or yaSSL and your version of
MySQL must be built with SSL support.

To make it easier to use secure connections, MySQL is bundled with
yaSSL as of MySQL 5.0.10. (MySQL and yaSSL employ the same licensing
model, whereas OpenSSL uses an Apache-style license.)  yaSSL support
initially was available only for a few platforms, but now it is
available on all platforms supported by Oracle Corporation.

To get secure connections to work with MySQL and SSL, you must do the
following:

  1. If you are not using a binary (precompiled) version of MySQL that
     has been built with SSL support, and you are going to use OpenSSL
     rather than the bundled yaSSL library, install OpenSSL if it has
     not already been installed. We have tested MySQL with OpenSSL
     0.9.6. To obtain OpenSSL, visit `http://www.openssl.org'.

     Building MySQL using OpenSSL requires a shared OpenSSL library,
     otherwise linker errors occur. Alternatively, build MySQL using
     yaSSL.

  2. If you are not using a binary (precompiled) version of MySQL that
     has been built with SSL support, configure a MySQL source
     distribution to use SSL. When you configure MySQL, invoke the
     `configure' script with the appropriate option to select the SSL
     library that you want to use.

     For yaSSL:

          shell> ./configure --with-yassl

     For OpenSSL:

          shell> ./configure --with-openssl

     Before MySQL 5.0, it was also neccessary to use `--with-vio', but
     that option is no longer required.

     Note that yaSSL support on Unix platforms requires that either
     `/dev/urandom' or `/dev/random' be available to retrieve true
     random numbers. For additional information (especially regarding
     yaSSL on Solaris versions prior to 2.8 and HP-UX), see Bug #13164.

  3. Make sure that the `user' in the `mysql' database includes the
     SSL-related columns (beginning with `ssl_' and `x509_'). If your
     `user' table does not have these columns, it must be upgraded; see
     *Note mysql-upgrade::.

  4. To check whether a server binary is compiled with SSL support,
     invoke it with the `--ssl' option. An error will occur if the
     server does not support SSL:

          shell> mysqld --ssl --help
          060525 14:18:52 [ERROR] mysqld: unknown option '--ssl'

     To check whether a running *Note `mysqld': mysqld. server supports
     SSL, examine the value of the `have_ssl' system variable (if you
     have no `have_ssl' variable, check for `have_openssl'):

          mysql> SHOW VARIABLES LIKE 'have_ssl';
          +---------------+-------+
          | Variable_name | Value |
          +---------------+-------+
          | have_ssl      | YES   |
          +---------------+-------+

     If the value is `YES', the server supports SSL connections. If the
     value is `DISABLED', the server supports SSL connections but was
     not started with the appropriate `--ssl-XXX' options (described
     later in this section).

To enable SSL connections, the proper SSL-related options must be used
(see *Note ssl-options::).

To start the MySQL server so that it permits clients to connect using
SSL, use the options that identify the key and certificate files the
server needs when establishing a secure connection:

     shell> mysqld --ssl-ca=CA-CERT.PEM \
            --ssl-cert=SERVER-CERT.PEM \
            --ssl-key=SERVER-KEY.PEM

   * `--ssl-ca' identifies the Certificate Authority (CA) certificate.

   * `--ssl-cert' identifies the server public key. This can be sent to
     the client and authenticated against the CA certificate that it
     has.

   * `--ssl-key' identifies the server private key.

To establish a secure connection to a MySQL server with SSL support,
the options that a client must specify depend on the SSL requirements
of the user account that the client uses. (See the discussion of the
`REQUIRE' clause in *Note grant::.)

If the account has no special SSL requirements or was created using a
*Note `GRANT': grant. statement that includes the `REQUIRE SSL' option,
a client can connect securely by using just the `--ssl-ca' option:

     shell> mysql --ssl-ca=CA-CERT.PEM

To require that a client certificate also be specified, create the
account using the `REQUIRE X509' option.  Then the client must also
specify the proper client key and certificate files or the server will
reject the connection:

     shell> mysql --ssl-ca=CA-CERT.PEM \
            --ssl-cert=CLIENT-CERT.PEM \
            --ssl-key=CLIENT-KEY.PEM

In other words, the options are similar to those used for the server.
Note that the Certificate Authority certificate has to be the same.

A client can determine whether the current connection with the server
uses SSL by checking the value of the `Ssl_cipher' status variable.
The value of `Ssl_cipher' is nonempty if SSL is used, and empty
otherwise. For example:

     mysql> SHOW STATUS LIKE 'Ssl_cipher';
     +---------------+--------------------+
     | Variable_name | Value              |
     +---------------+--------------------+
     | Ssl_cipher    | DHE-RSA-AES256-SHA |
     +---------------+--------------------+

For the *Note `mysql': mysql. client, you can use the `STATUS' or `\s'
command and check the `SSL' line:

     mysql> \s
     ...
     SSL:                    Not in use
     ...

Or:

     mysql> \s
     ...
     SSL:                    Cipher in use is DHE-RSA-AES256-SHA
     ...

To establish a secure connection from within an application program,
use the *Note `mysql_ssl_set()': mysql-ssl-set.  C API function to set
the appropriate certificate options before calling *Note
`mysql_real_connect()': mysql-real-connect.  See *Note mysql-ssl-set::.
After the connection is established, you can use *Note
`mysql_get_ssl_cipher()': mysql-get-ssl-cipher. to determine whether
SSL is in use. A non-`NULL' return value indicates a secure connection
and names the SSL cipher used for encryption. A `NULL' return value
indicates that SSL is not being used. See *Note mysql-get-ssl-cipher::.


File: manual.info,  Node: ssl-options,  Next: secure-create-certs,  Prev: secure-using-ssl,  Up: secure-connections

6.5.6.3 SSL Command Options
...........................

The following list describes options that are used for specifying the
use of SSL, certificate files, and key files.  They can be given on the
command line or in an option file.  These options are not available
unless MySQL has been built with SSL support. See *Note
secure-using-ssl::. (There are also `--master-ssl*' options that can be
used for setting up a secure connection from a slave replication server
to a master server; see *Note replication-options::.)

*SSL Option/Variable Summary*

Name           Cmd-Line    Option file System Var  Status Var  Var Scope   Dynamic
have_openssl                           Yes                     Global      No
have_ssl                               Yes                     Global      No
skip-ssl       Yes         Yes                                             
ssl            Yes         Yes                                             
ssl-ca         Yes         Yes                                 Global      No
- _Variable_:                          Yes                     Global      No
ssl_ca                                                                     
ssl-capath     Yes         Yes                                 Global      No
- _Variable_:                          Yes                     Global      No
ssl_capath                                                                 
ssl-cert       Yes         Yes                                 Global      No
- _Variable_:                          Yes                     Global      No
ssl_cert                                                                   
ssl-cipher     Yes         Yes                                 Global      No
- _Variable_:                          Yes                     Global      No
ssl_cipher                                                                 
ssl-key        Yes         Yes                                 Global      No
- _Variable_:                          Yes                     Global      No
ssl_key                                                                    

   *  `--ssl'

     For the server, this option specifies that the server permits SSL
     connections. For a client program, it permits the client to
     connect to the server using SSL. This option is not sufficient in
     itself to cause an SSL connection to be used. You must also
     specify the `--ssl-ca' option, and possibly the `--ssl-cert' and
     `--ssl-key' options.

     This option is more often used in its opposite form to override
     any other SSL options and indicate that SSL should _not_ be used.
     To do this, specify the option as `--skip-ssl' or `--ssl=0'.

     Note that use of `--ssl' does not _require_ an SSL connection. For
     example, if the server or client is compiled without SSL support,
     a normal unencrypted connection is used.

     The secure way to require use of an SSL connection is to create an
     account on the server that includes a `REQUIRE SSL' clause in the
     *Note `GRANT': grant. statement. Then use that account to connect
     to the server, where both the server and the client have SSL
     support enabled.

     The `REQUIRE' clause permits other SSL-related restrictions as
     well. The description of `REQUIRE' in *Note grant::, provides
     additional detail about which SSL command options may or must be
     specified by clients that connect using accounts that are created
     using the various `REQUIRE' options.

   *  `--ssl-ca=FILE_NAME'

     The path to a file that contains a list of trusted SSL CAs.

   *  `--ssl-capath=DIRECTORY_NAME'

     The path to a directory that contains trusted SSL CA certificates
     in PEM format.

   *  `--ssl-cert=FILE_NAME'

     The name of the SSL certificate file to use for establishing a
     secure connection.

   *  `--ssl-cipher=CIPHER_LIST'

     A list of permissible ciphers to use for SSL encryption. For
     greatest portability, CIPHER_LIST should be a list of one or more
     cipher names, separated by colons. Examples:

          --ssl-cipher=AES128-SHA
          --ssl-cipher=DHE-RSA-AES256-SHA:AES128-SHA

     This format is understood both by OpenSSL and yaSSL. OpenSSL
     supports a more flexible syntax for specifying ciphers, as
     described in the OpenSSL documentation at
     `http://www.openssl.org/docs/apps/ciphers.html'.  However, this
     extended syntax will fail if used with a MySQL installation
     compiled against yaSSL.

     If no cipher in the list is supported, SSL connections will not
     work.

   *  `--ssl-key=FILE_NAME'

     The name of the SSL key file to use for establishing a secure
     connection.

     If the key file is protected by a passphrase, and the MySQL
     distribution was built using OpenSSL, the program will prompt the
     user for the passphrase. The password must be given interactively;
     it cannot be stored in a file. If the passphrase is incorrect, the
     program continues as if it could not read the key. An error occurs
     if the key file is protected by a passphrase for distributions
     built using yaSSL.

   *  `--ssl-verify-server-cert'

     This option is available for client programs only, not the server.
     It causes the server's Common Name value in the certificate that
     the server sends to the client to be verified against the host
     name that the client uses for connecting to the server, and the
     connection is rejected if there is a mismatch. This feature can be
     used to prevent man-in-the-middle attacks. Verification is
     disabled by default. This option was added in MySQL 5.0.23.

As of MySQL 5.0.40, if you use SSL when establishing a client
connection, you can tell the client not to authenticate the server
certificate by specifying neither `--ssl-ca' nor `--ssl-capath'. The
server still verifies the client according to any applicable
requirements established using *Note `GRANT': grant.  statements for
the client, and it still uses any `--ssl-ca'/`--ssl-capath' values that
were passed to server at startup time.


File: manual.info,  Node: secure-create-certs,  Prev: ssl-options,  Up: secure-connections

6.5.6.4 Setting Up SSL Certificates for MySQL
.............................................

This section demonstrates how to set up SSL certificate and key files
for use by MySQL servers and clients. The first example shows a
simplified procedure such as you might use from the command line. The
second shows a script that contains more detail. The first two examples
are intended for use on Unix and both use the `openssl' command that is
part of OpenSSL. The third example describes how to set up SSL files on
Windows.

Following the third example, instructions are given for using the files
to test SSL connections. You can also use the files as described in
*Note secure-using-ssl::.

* Example 1: Creating SSL Files from the Command Line on Unix *

The following example shows a set of commands to create MySQL server
and client certificate and key files. You will need to respond to
several prompts by the `openssl' commands. To generate test files, you
can press Enter to all prompts. To generate files for production use,
you should provide nonempty responses.

     # Create clean environment
     shell> rm -rf newcerts
     shell> mkdir newcerts && cd newcerts

     # Create CA certificate
     shell> openssl genrsa 2048 > ca-key.pem
     shell> openssl req -new -x509 -nodes -days 1000 \
              -key ca-key.pem -out ca-cert.pem

     # Create server certificate, remove passphrase, and sign it
     shell> openssl req -newkey rsa:2048 -days 1000 \
              -nodes -keyout server-key.pem -out server-req.pem
     shell> openssl rsa -in server-key.pem -out server-key.pem
     shell> openssl x509 -req -in server-req.pem -days 1000 \
              -CA ca-cert.pem -CAkey ca-key.pem -set_serial 01 -out server-cert.pem

     # Create client certificate, remove passphrase, and sign it
     shell> openssl req -newkey rsa:2048 -days 1000 \
              -nodes -keyout client-key.pem -out client-req.pem
     shell> openssl rsa -in client-key.pem -out client-key.pem
     shell> openssl x509 -req -in client-req.pem -days 1000 \
              -CA ca-cert.pem -CAkey ca-key.pem -set_serial 01 -out client-cert.pem

After generating the certificates, verify them:

     mysql> openssl verify -CAfile ca-cert.pem server-cert.pem client-cert.pem

* Example 2: Creating SSL Files Using a Script on Unix *

Here is an example script that shows how to set up SSL certificates for
MySQL:

     DIR=`pwd`/openssl
     PRIV=$DIR/private

     mkdir $DIR $PRIV $DIR/newcerts
     cp /usr/share/ssl/openssl.cnf $DIR
     replace ./demoCA $DIR -- $DIR/openssl.cnf

     # Create necessary files: $database, $serial and $new_certs_dir
     # directory (optional)

     touch $DIR/index.txt
     echo "01" > $DIR/serial

     #
     # Generation of Certificate Authority(CA)
     #

     openssl req -new -x509 -keyout $PRIV/cakey.pem -out $DIR/ca-cert.pem \
         -days 3600 -config $DIR/openssl.cnf

     # Sample output:
     # Using configuration from /home/monty/openssl/openssl.cnf
     # Generating a 1024 bit RSA private key
     # ................++++++
     # .........++++++
     # writing new private key to '/home/monty/openssl/private/cakey.pem'
     # Enter PEM pass phrase:
     # Verifying password - Enter PEM pass phrase:
     # -----
     # You are about to be asked to enter information that will be
     # incorporated into your certificate request.
     # What you are about to enter is what is called a Distinguished Name
     # or a DN.
     # There are quite a few fields but you can leave some blank
     # For some fields there will be a default value,
     # If you enter '.', the field will be left blank.
     # -----
     # Country Name (2 letter code) [AU]:FI
     # State or Province Name (full name) [Some-State]:.
     # Locality Name (eg, city) []:
     # Organization Name (eg, company) [Internet Widgits Pty Ltd]:MySQL AB
     # Organizational Unit Name (eg, section) []:
     # Common Name (eg, YOUR name) []:MySQL admin
     # Email Address []:

     #
     # Create server request and key
     #
     openssl req -new -keyout $DIR/server-key.pem -out \
         $DIR/server-req.pem -days 3600 -config $DIR/openssl.cnf

     # Sample output:
     # Using configuration from /home/monty/openssl/openssl.cnf
     # Generating a 1024 bit RSA private key
     # ..++++++
     # ..........++++++
     # writing new private key to '/home/monty/openssl/server-key.pem'
     # Enter PEM pass phrase:
     # Verifying password - Enter PEM pass phrase:
     # -----
     # You are about to be asked to enter information that will be
     # incorporated into your certificate request.
     # What you are about to enter is what is called a Distinguished Name
     # or a DN.
     # There are quite a few fields but you can leave some blank
     # For some fields there will be a default value,
     # If you enter '.', the field will be left blank.
     # -----
     # Country Name (2 letter code) [AU]:FI
     # State or Province Name (full name) [Some-State]:.
     # Locality Name (eg, city) []:
     # Organization Name (eg, company) [Internet Widgits Pty Ltd]:MySQL AB
     # Organizational Unit Name (eg, section) []:
     # Common Name (eg, YOUR name) []:MySQL server
     # Email Address []:
     #
     # Please enter the following 'extra' attributes
     # to be sent with your certificate request
     # A challenge password []:
     # An optional company name []:

     #
     # Remove the passphrase from the key
     #
     openssl rsa -in $DIR/server-key.pem -out $DIR/server-key.pem

     #
     # Sign server cert
     #
     openssl ca  -policy policy_anything -out $DIR/server-cert.pem \
         -config $DIR/openssl.cnf -infiles $DIR/server-req.pem

     # Sample output:
     # Using configuration from /home/monty/openssl/openssl.cnf
     # Enter PEM pass phrase:
     # Check that the request matches the signature
     # Signature ok
     # The Subjects Distinguished Name is as follows
     # countryName           :PRINTABLE:'FI'
     # organizationName      :PRINTABLE:'MySQL AB'
     # commonName            :PRINTABLE:'MySQL admin'
     # Certificate is to be certified until Sep 13 14:22:46 2003 GMT
     # (365 days)
     # Sign the certificate? [y/n]:y
     #
     #
     # 1 out of 1 certificate requests certified, commit? [y/n]y
     # Write out database with 1 new entries
     # Data Base Updated

     #
     # Create client request and key
     #
     openssl req -new -keyout $DIR/client-key.pem -out \
         $DIR/client-req.pem -days 3600 -config $DIR/openssl.cnf

     # Sample output:
     # Using configuration from /home/monty/openssl/openssl.cnf
     # Generating a 1024 bit RSA private key
     # .....................................++++++
     # .............................................++++++
     # writing new private key to '/home/monty/openssl/client-key.pem'
     # Enter PEM pass phrase:
     # Verifying password - Enter PEM pass phrase:
     # -----
     # You are about to be asked to enter information that will be
     # incorporated into your certificate request.
     # What you are about to enter is what is called a Distinguished Name
     # or a DN.
     # There are quite a few fields but you can leave some blank
     # For some fields there will be a default value,
     # If you enter '.', the field will be left blank.
     # -----
     # Country Name (2 letter code) [AU]:FI
     # State or Province Name (full name) [Some-State]:.
     # Locality Name (eg, city) []:
     # Organization Name (eg, company) [Internet Widgits Pty Ltd]:MySQL AB
     # Organizational Unit Name (eg, section) []:
     # Common Name (eg, YOUR name) []:MySQL user
     # Email Address []:
     #
     # Please enter the following 'extra' attributes
     # to be sent with your certificate request
     # A challenge password []:
     # An optional company name []:

     #
     # Remove the passphrase from the key
     #
     openssl rsa -in $DIR/client-key.pem -out $DIR/client-key.pem

     #
     # Sign client cert
     #

     openssl ca  -policy policy_anything -out $DIR/client-cert.pem \
         -config $DIR/openssl.cnf -infiles $DIR/client-req.pem

     # Sample output:
     # Using configuration from /home/monty/openssl/openssl.cnf
     # Enter PEM pass phrase:
     # Check that the request matches the signature
     # Signature ok
     # The Subjects Distinguished Name is as follows
     # countryName           :PRINTABLE:'FI'
     # organizationName      :PRINTABLE:'MySQL AB'
     # commonName            :PRINTABLE:'MySQL user'
     # Certificate is to be certified until Sep 13 16:45:17 2003 GMT
     # (365 days)
     # Sign the certificate? [y/n]:y
     #
     #
     # 1 out of 1 certificate requests certified, commit? [y/n]y
     # Write out database with 1 new entries
     # Data Base Updated

     #
     # Create a my.cnf file that you can use to test the certificates
     #

     cnf=""
     cnf="$cnf [client]"
     cnf="$cnf ssl-ca=$DIR/ca-cert.pem"
     cnf="$cnf ssl-cert=$DIR/client-cert.pem"
     cnf="$cnf ssl-key=$DIR/client-key.pem"
     cnf="$cnf [mysqld]"
     cnf="$cnf ssl-ca=$DIR/ca-cert.pem"
     cnf="$cnf ssl-cert=$DIR/server-cert.pem"
     cnf="$cnf ssl-key=$DIR/server-key.pem"
     echo $cnf | replace " " '
     ' > $DIR/my.cnf

* Example 3: Creating SSL Files on Windows *

Download OpenSSL for Windows. An overview of available packages can be
seen here: `http://www.slproweb.com/products/Win32OpenSSL.html' Choose
the Win32 OpenSSL Light or Win64 OpenSSL Light package, depending on
your architecture (32-bit or 64-bit). The default installation location
will be `C:\OpenSSL-Win32' or `C:\OpenSSL-Win64', depending on which
package you downloaded. The following instructions assume a default
location of `C:\OpenSSL-Win32'. Modify this as necessary if you are
using the 64-bit package.

if a message occurs during setup indicating `'...critical component is
missing: Microsoft Visual C++ 2008 Redistributables'', cancel the setup
and download one of the following packages as well, again depending on
your architecture (32-bit or 64-bit):

   * Visual C++ 2008 Redistributables (x86), available at:
     `http://www.microsoft.com/downloads/details.aspx?familyid=9B2DA534-3E03-4391-8A4D-074B9F2BC1BF"isplaylang=en'

   * Visual C++ 2008 Redistributables (x64), available at:
     `http://www.microsoft.com/downloads/details.aspx?familyid=bd2a6171-e2d6-4230-b809-9a8d7548c1b6"isplaylang=en'

After installing the additional package, restart the OpenSSL setup.

During installation, leave the default `C:\OpenSSL-Win32' as the
install path, and also leave the default option `'Copy OpenSSL DLL files
to the Windows system directory'' selected.

When the installation has finished, add `C:\OpenSSL-Win32\bin' to the
Windows System Path variable of your server:

  1. On the Windows desktop, right-click the `My Computer' icon, and
     select `Properties'.

  2. Select the `Advanced' tab from the `System Properties' menu that
     appears, and click the `Environment Variables' button.

  3. Under `System Variables', select `Path', then click the `Edit'
     button. The `Edit System Variable' dialogue should appear.

  4. Add `';C:\OpenSSL-Win32\bin'' to the end (notice the semicolon).

  5. Press OK 3 times.

  6. Check that OpenSSL was correctly integrated into the Path variable
     by opening a new command console (`Start>Run>cmd.exe') and
     verifying that OpenSSL is available:

          Microsoft Windows [Version ...]
          Copyright (c) 2006 Microsoft Corporation. All rights reserved.

          C:\Windows\system32>cd \

          C:\>openssl
          OpenSSL> exit <<< If you see the OpenSSL prompt, installation was successful.

          C:\>

Depending on your version of Windows, the preceding instructions might
be slightly different.

After OpenSSL has been installed, use instructions similar to those
from from Example 1 (shown earlier in this section), with the following
changes:

   * Change the following Unix commands:

          # Create clean environment
          shell> rm -rf newcerts
          shell> mkdir newcerts && cd newcerts

     On Windows, use these commands instead:

          # Create clean environment
          shell> md c:\newcerts
          shell> cd c:\newcerts

   * When a `'\'' character is shown at the end of a command line, this
     `'\'' character must be removed and the command lines entered all
     on a single line.

* Testing SSL Connections *

To test SSL connections, start the server as follows, where `$DIR' is
the path name to the directory where the sample `my.cnf' option file (or
`my.ini' on Windows) is located:

     shell> mysqld --defaults-file=$DIR/my.cnf &

Then invoke a client program using the same option file:

     shell> mysql --defaults-file=$DIR/my.cnf

If you have a MySQL source distribution, you can also test your setup
by modifying the preceding `my.cnf' file to refer to the demonstration
certificate and key files in the `SSL' directory of the distribution.


File: manual.info,  Node: windows-and-ssh,  Next: account-activity-auditing,  Prev: secure-connections,  Up: user-account-management

6.5.7 Connecting to MySQL Remotely from Windows with SSH
--------------------------------------------------------

This section describes how to get a secure connection to a remote MySQL
server with SSH. The information was provided by David Carlson
<dcarlson@mplcomm.com>.

  1. Install an SSH client on your Windows machine. As a user, the best
     nonfree one I have found is from `SecureCRT' from
     `http://www.vandyke.com/'. Another option is `f-secure' from
     `http://www.f-secure.com/'. You can also find some free ones on
     `Google' at
     `http://directory.google.com/Top/Computers/Internet/Protocols/SSH/Clients/Windows/'.

  2. Start your Windows SSH client. Set `Host_Name =
     YOURMYSQLSERVER_URL_OR_IP'.  Set `userid=YOUR_USERID' to log in to
     your server. This `userid' value might not be the same as the user
     name of your MySQL account.

  3. Set up port forwarding. Either do a remote forward (Set
     `local_port: 3306', `remote_host: YOURMYSQLSERVERNAME_OR_IP',
     `remote_port: 3306' ) or a local forward (Set `port: 3306', `host:
     localhost', `remote port: 3306').

  4. Save everything, otherwise you will have to redo it the next time.

  5. Log in to your server with the SSH session you just created.

  6. On your Windows machine, start some ODBC application (such as
     Access).

  7. Create a new file in Windows and link to MySQL using the ODBC
     driver the same way you normally do, except type in `localhost'
     for the MySQL host server, not YOURMYSQLSERVERNAME.

At this point, you should have an ODBC connection to MySQL, encrypted
using SSH.


File: manual.info,  Node: account-activity-auditing,  Prev: windows-and-ssh,  Up: user-account-management

6.5.8 Auditing MySQL Account Activity
-------------------------------------

Applications can use the following guidelines to perform auditing that
ties database activity to MySQL accounts.

MySQL accounts correspond to rows in the `mysql.user' table. When a
client connects successfully, the server authenticates the client to a
particular row in this table. The `User' and `Host' column values in
this row uniquely identify the account and correspond to the
`'USER_NAME'@'HOST_NAME'' format in which account names are written in
SQL statements.

The account used to authenticate a client determines which privileges
the client has. Normally, the `CURRENT_USER()' function can be invoked
to determine which account this is for the client user.  Its value is
constructed from the `User' and `Host' columns of the `user' table row
for the account.

However, there are circumstances under which the `CURRENT_USER()' value
corresponds not to the client user but to a different account. This
occurs in contexts when privilege checking is not based the client's
account:

   * Stored routines (procedures and functions) defined with the `SQL
     SECURITY DEFINER' characteristic.

   * Views defined with the `SQL SECURITY DEFINER' characteristic (as
     of MySQL 5.0.24).

   * Triggers (as of MySQL 5.0.17).

In those contexts, privilege checking is done against the `DEFINER'
account and `CURRENT_USER()' refers to that account, not to the account
for the client who invoked the stored routine or view or who caused the
trigger to activate. To determine the invoking user, you can call the
`USER()' function, which returns a value indicating the actual user
name provided by the client and the host from which the client
connected. However, this value does not necessarily correspond directly
to an account in the `user' table, because the `USER()' value never
contains wildcards, whereas account values (as returned by
`CURRENT_USER()') may contain user name and host name wildcards.

For example, a blank user name matches any user, so an account of
`''@'localhost'' enables clients to connect as an anonymous user from
the local host with any user name. If this case, if a client connects
as `user1' from the local host, `USER()' and `CURRENT_USER()' return
different values:

     mysql> SELECT USER(), CURRENT_USER();
     +-----------------+----------------+
     | USER()          | CURRENT_USER() |
     +-----------------+----------------+
     | user1@localhost | @localhost     |
     +-----------------+----------------+

The host name part of an account can contain wildcards, too. If the
host name contains a `'%'' or `'_'' pattern character or uses netmask
notation, the account can be used for clients connecting from multiple
hosts and the `CURRENT_USER()' value will not indicate which one. For
example, the account `'user2'@'%.example.com'' can be used by `user2'
to connect from any host in the `example.com' domain. If `user2'
connects from `remote.example.com', `USER()' and `CURRENT_USER()'
return different values:

     mysql> SELECT USER(), CURRENT_USER();
     +--------------------------+---------------------+
     | USER()                   | CURRENT_USER()      |
     +--------------------------+---------------------+
     | user2@remote.example.com | user2@%.example.com |
     +--------------------------+---------------------+

If an application must invoke `USER()' for user auditing (for example,
if it does auditing from within triggers) but must also be able to
associate the `USER()' value with an account in the `user' table, it is
necessary to avoid accounts that contain wildcards in the `User' or
`Host' column.  Specifically, do not permit `User' to be empty (which
creates an anonymous-user account), and do not permit pattern
characters or netmask notation in `Host' values. All accounts must have
a nonempty `User' value and literal `Host' value.

With respect to the previous examples, the `''@'localhost'' and
`'user2'@'%.example.com'' accounts should be changed not to use
wildcards:

     RENAME USER ''@'localhost' TO 'user1'@'localhost';
     RENAME USER 'user2'@'%.example.com' TO 'user2'@'remote.example.com';

If `user2' must be able to connect from several hosts in the
`example.com' domain, there should be a separate account for each host.

To extract the user name or host name part from a `CURRENT_USER()' or
`USER()' value, use the `SUBSTRING()' function:

     mysql> SELECT SUBSTRING_INDEX(CURRENT_USER(),'@',1);
     +---------------------------------------+
     | SUBSTRING_INDEX(CURRENT_USER(),'@',1) |
     +---------------------------------------+
     | user1                                 |
     +---------------------------------------+

     mysql> SELECT SUBSTRING_INDEX(CURRENT_USER(),'@',-1);
     +----------------------------------------+
     | SUBSTRING_INDEX(CURRENT_USER(),'@',-1) |
     +----------------------------------------+
     | localhost                              |
     +----------------------------------------+


File: manual.info,  Node: multiple-servers,  Prev: user-account-management,  Up: server-administration

6.6 Running Multiple MySQL Instances on One Machine
===================================================

* Menu:

* multiple-data-directories::    Setting Up Multiple Data Directories
* multiple-windows-servers::     Running Multiple MySQL Instances on Windows
* multiple-unix-servers::        Running Multiple MySQL Instances on Unix
* multiple-server-clients::      Using Client Programs in a Multiple-Server Environment

In some cases, you might want to run multiple instances of MySQL on a
single machine. You might want to test a new MySQL release while
leaving an existing production setup undisturbed. Or you might want to
give different users access to different *Note `mysqld': mysqld.
servers that they manage themselves. (For example, you might be an
Internet Service Provider that wants to provide independent MySQL
installations for different customers.)

It is possible to use a different MySQL server binary per instance, or
use the same binary for multiple instances, or any combination of the
two approaches. For example, you might run a server from MySQL 4.1 and
one from MySQL 5.0, to see how different versions handle a given
workload. Or you might run multiple instances of the current production
version, each managing a different set of databases.

Whether or not you use distinct server binaries, each instance that you
run must be configured with unique values for several operating
parameters. This eliminates the potential for conflict between
instances. Parameters can be set on the command line, in option files,
or by setting environment variables. See *Note program-options::. To
see the values used by a given instance, connect to it and execute a
*Note `SHOW VARIABLES': show-variables. statement.

The primary resource managed by a MySQL instance is the data directory.
Each instance should use a different data directory, the location of
which is specified using the `--datadir=PATH' option. For methods of
configuring each instance with its own data directory, and warnings
about the dangers of failing to do so, see *Note
multiple-data-directories::.

In addition to using different data directories, several other options
must have different values for each server instance:

   * `--port=PORT_NUM'

     `--port' controls the port number for TCP/IP connections.
     Alternatively, if the host has multiple network addresses, you can
     use `--bind-address' to cause each server to listen to a different
     address.

   * `--socket=PATH'

     `--socket' controls the Unix socket file path on Unix or the named
     pipe name on Windows. On Windows, it is necessary to specify
     distinct pipe names only for those servers configured to permit
     named-pipe connections.

   * `--shared-memory-base-name=NAME'

     This option is used only on Windows. It designates the
     shared-memory name used by a Windows server to permit clients to
     connect using shared memory. It is necessary to specify distinct
     shared-memory names only for those servers configured to permit
     shared-memory connections.

   * `--pid-file=FILE_NAME'

     This option indicates the path name of the file in which the
     server writes its process ID.

If you use the following log file options, their values must differ for
each server:

   * `--log[=FILE_NAME]'

   * `--log-bin[=FILE_NAME]'

   * `--log-error[=FILE_NAME]'

   * `--bdb-logdir=FILE_NAME'

For further discussion of log file options, see *Note server-logs::.

To achieve better performance, you can specify the following options
differently for each server, to spread the load between several
physical disks:

   * `--tmpdir=PATH'

   * `--bdb-tmpdir=PATH'

Having different temporary directories also makes it easier to
determine which MySQL server created any given temporary file.

If you have multiple MySQL installations in different locations, you
can specify the base directory for each installation with the
`--basedir=PATH' option. This causes each instance to automatically use
a different data directory, log files, and PID file because the default
for each of those parameters is relative to the base directory. In that
case, the only other options you need to specify are the `--socket' and
`--port' options. Suppose that you install different versions of MySQL
using `tar' file binary distributions. These install in different
locations, so you can start the server for each installation using the
command `bin/mysqld_safe' under its corresponding base directory. *Note
`mysqld_safe': mysqld-safe. determines the proper `--basedir' option to
pass to *Note `mysqld': mysqld, and you need specify only the
`--socket' and `--port' options to *Note `mysqld_safe': mysqld-safe.

As discussed in the following sections, it is possible to start
additional servers by specifying appropriate command options or by
setting environment variables. However, if you need to run multiple
servers on a more permanent basis, it is more convenient to use option
files to specify for each server those option values that must be
unique to it. The `--defaults-file' option is useful for this purpose.


File: manual.info,  Node: multiple-data-directories,  Next: multiple-windows-servers,  Prev: multiple-servers,  Up: multiple-servers

6.6.1 Setting Up Multiple Data Directories
------------------------------------------

Each MySQL Instance on a machine should have its own data directory.
The location is specified using the `--datadir=PATH' option.

There are different methods of setting up a data directory for a new
instance:

   * Create a new data directory

   * Copy an existing data directory

The following discussion provides more detail about each method.

*Warning*:

Normally, you should never have two servers that update data in the
same databases. This may lead to unpleasant surprises if your operating
system does not support fault-free system locking. If (despite this
warning) you run multiple servers using the same data directory and
they have logging enabled, you must use the appropriate options to
specify log file names that are unique to each server. Otherwise, the
servers try to log to the same files.

Even when the preceding precautions are observed, this kind of setup
works only with `MyISAM' and `MERGE' tables, and not with any of the
other storage engines. Also, this warning against sharing a data
directory among servers always applies in an NFS environment.
Permitting multiple MySQL servers to access a common data directory
over NFS is a _very bad idea_. The primary problem is that NFS is the
speed bottleneck. It is not meant for such use. Another risk with NFS
is that you must devise a way to ensure that two or more servers do not
interfere with each other. Usually NFS file locking is handled by the
`lockd' daemon, but at the moment there is no platform that performs
locking 100% reliably in every situation.

* Create a New Data Directory *

With this method, the data directory will be in the same state as when
you first install MySQL. It will have the default set of MySQL accounts
and no user data.

On Unix, initialize the data directory by running *Note
`mysql_install_db': mysql-install-db. See *Note unix-postinstallation::.

On Windows, the data directory is included in MySQL distributions.  If
you obtain a distribution in Windows Zip archive format, you can unpack
it into a temporary location, then copy the `data' directory from this
location to where you are setting up the new instance.

* Copy an Existing Data Directory *

With this method, any MySQL accounts or user data present in the data
directory are carried over to the new data directory.

  1. Stop the existing MySQL instance using the data directory.  This
     must be a clean shutdown so that the instance flushes any pending
     changes to disk.

  2. Copy the data directory to the location where the new data
     directory should be.

  3. Copy the `my.cnf' or `my.ini' option file used by the existing
     instance. This serves as a basis for the new instance.

  4. Modify the new option file so that any pathnames referring to the
     original data directory refer to the new data directory.  Also,
     modify any other options that must be unique per instance, such as
     the TCP/IP port number and the log files.  For a list of
     parameters that must be unique per instance, see *Note
     multiple-servers::.

  5. Start the new instance, telling it to use the new option file.


File: manual.info,  Node: multiple-windows-servers,  Next: multiple-unix-servers,  Prev: multiple-data-directories,  Up: multiple-servers

6.6.2 Running Multiple MySQL Instances on Windows
-------------------------------------------------

* Menu:

* multiple-windows-command-line-servers::  Starting Multiple MySQL Instances at the Windows Command Line
* multiple-windows-services::    Starting Multiple MySQL Instances as Windows Services

You can run multiple servers on Windows by starting them manually from
the command line, each with appropriate operating parameters, or by
installing several servers as Windows services and running them that
way. General instructions for running MySQL from the command line or as
a service are given in *Note windows-installation::. The following
sections describe how to start each server with different values for
those options that must be unique per server, such as the data
directory. These options are listed in *Note multiple-servers::.


File: manual.info,  Node: multiple-windows-command-line-servers,  Next: multiple-windows-services,  Prev: multiple-windows-servers,  Up: multiple-windows-servers

6.6.2.1 Starting Multiple MySQL Instances at the Windows Command Line
.....................................................................

The procedure for starting a single MySQL server manually from the
command line is described in *Note windows-start-command-line::. To
start multiple servers this way, you can specify the appropriate
options on the command line or in an option file. It is more convenient
to place the options in an option file, but it is necessary to make
sure that each server gets its own set of options. To do this, create
an option file for each server and tell the server the file name with a
`--defaults-file' option when you run it.

Suppose that you want to run *Note `mysqld': mysqld. on port 3307 with
a data directory of `C:\mydata1', and *Note `mysqld-debug': mysqld. on
port 3308 with a data directory of `C:\mydata2'. Use this procedure:

  1. Make sure that each data directory exists, including its own copy
     of the `mysql' database that contains the grant tables.

  2. Create two option files. For example, create one file named
     `C:\my-opts1.cnf' that looks like this:

          [mysqld]
          datadir = C:/mydata1
          port = 3307

     Create a second file named `C:\my-opts2.cnf' that looks like this:

          [mysqld]
          datadir = C:/mydata2
          port = 3308

  3. Use the `--defaults-file' option to start each server with its own
     option file:

          C:\> C:\mysql\bin\mysqld --defaults-file=C:\my-opts1.cnf
          C:\> C:\mysql\bin\mysqld-debug --defaults-file=C:\my-opts2.cnf

     Each server starts in the foreground (no new prompt appears until
     the server exits later), so you will need to issue those two
     commands in separate console windows.

To shut down the servers, connect to each using the appropriate port
number:

     C:\> C:\mysql\bin\mysqladmin --port=3307 shutdown
     C:\> C:\mysql\bin\mysqladmin --port=3308 shutdown

Servers configured as just described permit clients to connect over
TCP/IP. If your version of Windows supports named pipes and you also
want to permit named-pipe connections, use the *Note `mysqld-nt':
mysqld. or *Note `mysqld-debug': mysqld.  server and specify options
that enable the named pipe and specify its name. Each server that
supports named-pipe connections must use a unique pipe name. For
example, the `C:\my-opts1.cnf' file might be written like this:

     [mysqld]
     datadir = C:/mydata1
     port = 3307
     enable-named-pipe
     socket = mypipe1

Modify `C:\my-opts2.cnf' similarly for use by the second server. Then
start the servers as described previously.

A similar procedure applies for servers that you want to permit
shared-memory connections. Enable such connections with the
`--shared-memory' option and specify a unique shared-memory name for
each server with the `--shared-memory-base-name' option.


File: manual.info,  Node: multiple-windows-services,  Prev: multiple-windows-command-line-servers,  Up: multiple-windows-servers

6.6.2.2 Starting Multiple MySQL Instances as Windows Services
.............................................................

On Windows, a MySQL server can run as a Windows service. The procedures
for installing, controlling, and removing a single MySQL service are
described in *Note windows-start-service::.

To set up multiple MySQL services, you must make sure that each
instance uses a different service name in addition to the other
parameters that must be unique per instance.

For the following instructions, suppose that you want to run the *Note
`mysqld-nt': mysqld. server from two different versions of MySQL that
are installed at `C:\mysql-4.1.24' and `C:\mysql-5.0.95', respectively.
(This might be the case if you're running 4.1.24 as your production
server, but also want to conduct tests using 5.0.95.)

To install MySQL as a Windows service, use the `--install' or
`--install-manual' option. For information about these options, see
*Note windows-start-service::.

Based on the preceding information, you have several ways to set up
multiple services. The following instructions describe some examples.
Before trying any of them, shut down and remove any existing MySQL
services.

   * *Approach 1:* Specify the options for all services in one of the
     standard option files. To do this, use a different service name
     for each server. Suppose that you want to run the 4.1.24 *Note
     `mysqld-nt': mysqld. using the service name of `mysqld1' and the
     5.0.95 *Note `mysqld-nt': mysqld. using the service name
     `mysqld2'. In this case, you can use the `[mysqld1]' group for
     4.1.24 and the `[mysqld2]' group for 5.0.95.  For example, you can
     set up `C:\my.cnf' like this:

          # options for mysqld1 service
          [mysqld1]
          basedir = C:/mysql-4.1.24
          port = 3307
          enable-named-pipe
          socket = mypipe1

          # options for mysqld2 service
          [mysqld2]
          basedir = C:/mysql-5.0.95
          port = 3308
          enable-named-pipe
          socket = mypipe2

     Install the services as follows, using the full server path names
     to ensure that Windows registers the correct executable program
     for each service:

          C:\> C:\mysql-4.1.24\bin\mysqld-nt --install mysqld1
          C:\> C:\mysql-5.0.95\bin\mysqld-nt --install mysqld2

     To start the services, use the services manager, or use `NET
     START' with the appropriate service names:

          C:\> NET START mysqld1
          C:\> NET START mysqld2

     To stop the services, use the services manager, or use `NET STOP'
     with the appropriate service names:

          C:\> NET STOP mysqld1
          C:\> NET STOP mysqld2

   * *Approach 2:* Specify options for each server in separate files
     and use `--defaults-file' when you install the services to tell
     each server what file to use.  In this case, each file should list
     options using a `[mysqld]' group.

     With this approach, to specify options for the 4.1.24 *Note
     `mysqld-nt': mysqld, create a file `C:\my-opts1.cnf' that looks
     like this:

          [mysqld]
          basedir = C:/mysql-4.1.24
          port = 3307
          enable-named-pipe
          socket = mypipe1

     For the 5.0.95 *Note `mysqld-nt': mysqld, create a file
     `C:\my-opts2.cnf' that looks like this:

          [mysqld]
          basedir = C:/mysql-5.0.95
          port = 3308
          enable-named-pipe
          socket = mypipe2

     Install the services as follows (enter each command on a single
     line):

          C:\> C:\mysql-4.1.24\bin\mysqld-nt --install mysqld1
                     --defaults-file=C:\my-opts1.cnf
          C:\> C:\mysql-5.0.95\bin\mysqld-nt --install mysqld2
                     --defaults-file=C:\my-opts2.cnf

     When you install a MySQL server as a service and use a
     `--defaults-file' option, the service name must precede the option.

     After installing the services, start and stop them the same way as
     in the preceding example.

To remove multiple services, use *Note `mysqld --remove': mysqld. for
each one, specifying a service name following the `--remove' option. If
the service name is the default (`MySQL'), you can omit it.


File: manual.info,  Node: multiple-unix-servers,  Next: multiple-server-clients,  Prev: multiple-windows-servers,  Up: multiple-servers

6.6.3 Running Multiple MySQL Instances on Unix
----------------------------------------------

One way is to run multiple MySQL instances on Unix is to compile
different servers with different default TCP/IP ports and Unix socket
files so that each one listens on different network interfaces.
Compiling in different base directories for each installation also
results automatically in a separate, compiled-in data directory, log
file, and PID file location for each server.

Assume that an existing 4.1 server is configured for the default TCP/IP
port number (3306) and Unix socket file (`/tmp/mysql.sock'). To
configure a new 5.0.95 server to have different operating parameters,
use a `configure' command something like this:

     shell> ./configure --with-tcp-port=PORT_NUMBER \
                  --with-unix-socket-path=FILE_NAME \
                  --prefix=/usr/local/mysql-5.0.95

Here, PORT_NUMBER and FILE_NAME must be different from the default
TCP/IP port number and Unix socket file path name, and the `--prefix'
value should specify an installation directory different from the one
under which the existing MySQL installation is located.

If you have a MySQL server listening on a given port number, you can
use the following command to find out what operating parameters it is
using for several important configurable variables, including the base
directory and Unix socket file name:

     shell> mysqladmin --host=HOST_NAME --port=PORT_NUMBER variables

With the information displayed by that command, you can tell what
option values _not_ to use when configuring an additional server.

If you specify `localhost' as the host name, *Note `mysqladmin':
mysqladmin. defaults to using a Unix socket file connection rather than
TCP/IP. To explicitly specify the connection protocol, use the
`--protocol={TCP|SOCKET|PIPE|MEMORY}' option.

You need not compile a new MySQL server just to start with a different
Unix socket file and TCP/IP port number. It is also possible to use the
same server binary and start each invocation of it with different
parameter values at runtime. One way to do so is by using command-line
options:

     shell> mysqld_safe --socket=FILE_NAME --port=PORT_NUMBER

To start a second server, provide different `--socket' and `--port'
option values, and pass a `--datadir=PATH' option to *Note
`mysqld_safe': mysqld-safe. so that the server uses a different data
directory.

Alternatively, put the options for each server in a different option
file, then start each server using a `--defaults-file' option that
specifies the path to the appropriate option file. For example, if the
option files for two server instances are named
`/usr/local/mysql/my.cnf' and `/usr/local/mysql/my.cnf2', start the
servers like this: command:

     shell> mysqld_safe --defaults-file=/usr/local/mysql/my.cnf
     shell> mysqld_safe --defaults-file=/usr/local/mysql/my.cnf2

Another way to achieve a similar effect is to use environment variables
to set the Unix socket file name and TCP/IP port number:

     shell> MYSQL_UNIX_PORT=/tmp/mysqld-new.sock
     shell> MYSQL_TCP_PORT=3307
     shell> export MYSQL_UNIX_PORT MYSQL_TCP_PORT
     shell> mysql_install_db --user=mysql
     shell> mysqld_safe --datadir=/path/to/datadir &

This is a quick way of starting a second server to use for testing. The
nice thing about this method is that the environment variable settings
apply to any client programs that you invoke from the same shell. Thus,
connections for those clients are automatically directed to the second
server.

*Note environment-variables::, includes a list of other environment
variables you can use to affect MySQL programs.

On Unix, the *Note `mysqld_multi': mysqld-multi. script provides
another way to start multiple servers. See *Note mysqld-multi::.


File: manual.info,  Node: multiple-server-clients,  Prev: multiple-unix-servers,  Up: multiple-servers

6.6.4 Using Client Programs in a Multiple-Server Environment
------------------------------------------------------------

To connect with a client program to a MySQL server that is listening to
different network interfaces from those compiled into your client, you
can use one of the following methods:

   * Start the client with `--host=HOST_NAME' `--port=PORT_NUMBER' to
     connect using TCP/IP to a remote server, with `--host=127.0.0.1'
     `--port=PORT_NUMBER' to connect using TCP/IP to a local server, or
     with `--host=localhost' `--socket=FILE_NAME' to connect to a local
     server using a Unix socket file or a Windows named pipe.

   * Start the client with `--protocol=TCP' to connect using TCP/IP,
     `--protocol=SOCKET' to connect using a Unix socket file,
     `--protocol=PIPE' to connect using a named pipe, or
     `--protocol=MEMORY' to connect using shared memory. For TCP/IP
     connections, you may also need to specify `--host' and `--port'
     options. For the other types of connections, you may need to
     specify a `--socket' option to specify a Unix socket file or
     Windows named-pipe name, or a `--shared-memory-base-name' option
     to specify the shared-memory name. Shared-memory connections are
     supported only on Windows.

   * On Unix, set the `MYSQL_UNIX_PORT' and `MYSQL_TCP_PORT'
     environment variables to point to the Unix socket file and TCP/IP
     port number before you start your clients. If you normally use a
     specific socket file or port number, you can place commands to set
     these environment variables in your `.login' file so that they
     apply each time you log in. See *Note environment-variables::.

   * Specify the default Unix socket file and TCP/IP port number in the
     `[client]' group of an option file. For example, you can use
     `C:\my.cnf' on Windows, or the `.my.cnf' file in your home
     directory on Unix. See *Note option-files::.

   * In a C program, you can specify the socket file or port number
     arguments in the *Note `mysql_real_connect()': mysql-real-connect.
     call. You can also have the program read option files by calling
     *Note `mysql_options()': mysql-options. See *Note
     c-api-functions::.

   * If you are using the Perl `DBD::mysql' module, you can read
     options from MySQL option files. For example:

          $dsn = "DBI:mysql:test;mysql_read_default_group=client;"
                  . "mysql_read_default_file=/usr/local/mysql/data/my.cnf";
          $dbh = DBI->connect($dsn, $user, $password);

     See *Note apis-perl::.

     Other programming interfaces may provide similar capabilities for
     reading option files.


File: manual.info,  Node: backup-and-recovery,  Next: optimization,  Prev: server-administration,  Up: Top

7 Backup and Recovery
*********************

* Menu:

* backup-types::                 Backup and Recovery Types
* backup-methods::               Database Backup Methods
* backup-strategy-example::      Example Backup and Recovery Strategy
* using-mysqldump::              Using `mysqldump' for Backups
* point-in-time-recovery::       Point-in-Time (Incremental) Recovery Using the Binary Log
* myisam-table-maintenance::     `MyISAM' Table Maintenance and Crash Recovery

It is important to back up your databases so that you can recover your
data and be up and running again in case problems occur, such as system
crashes, hardware failures, or users deleting data by mistake. Backups
are also essential as a safeguard before upgrading a MySQL
installation, and they can be used to transfer a MySQL installation to
another system or to set up replication slave servers.

MySQL offers a variety of backup strategies from which you can choose
the methods that best suit the requirements for your installation. This
chapter discusses several backup and recovery topics with which you
should be familiar:

   * Types of backups: Logical versus physical, full versus
     incremental, and so forth

   * Methods for creating backups

   * Recovery methods, including point-in-time recovery

   * Backup scheduling, compression, and encryption

   * Table maintenance, to enable recovery of corrupt tables

* Additional Resources *

Resources related to backup or to maintaining data availability include
the following:

   * A forum dedicated to backup issues is available at
     `http://forums.mysql.com/list.php?93'.

   * Details for *Note `mysqldump': mysqldump, *Note `mysqlhotcopy':
     mysqlhotcopy, and other MySQL backup programs can be found in
     *Note programs::.

   * The syntax of the SQL statements described here is given in *Note
     sql-syntax::.

   * For additional information about `InnoDB' backup procedures, see
     *Note innodb-backup::.

   * Replication enables you to maintain identical data on multiple
     servers. This has several benefits, such as enabling client query
     load to be distributed over servers, availability of data even if
     a given server is taken offline or fails, and the ability to make
     backups with no impact on the master by using a slave server. See
     *Note replication::.

   * MySQL Cluster provides a high-availability, high-redundancy
     version of MySQL adapted for the distributed computing
     environment. See *Note mysql-cluster::. For information
     specifically about MySQL Cluster backup, see *Note
     mysql-cluster-backup::.


File: manual.info,  Node: backup-types,  Next: backup-methods,  Prev: backup-and-recovery,  Up: backup-and-recovery

7.1 Backup and Recovery Types
=============================

This section describes the characteristics of different types of
backups.

*Logical Versus Physical (Raw) Backups*

Logical backups save information represented as logical database
structure (*Note `CREATE DATABASE': create-database, *Note `CREATE
TABLE': create-table. statements) and content (*Note `INSERT': insert.
statements or delimited-text files). Physical backups consist of raw
copies of the directories and files that store database contents.

Logical backup methods have these characteristics:

   * The backup is done by querying the MySQL server to obtain database
     structure and content information.

   * Backup is slower than physical methods because the server must
     access database information and convert it to logical format.  If
     the output is written on the client side, the server must also
     send it to the backup program.

   * Output is larger than for physical backup, particularly when saved
     in text format.

   * Backup and restore granularity is available at the server level
     (all databases), database level (all tables in a particular
     database), or table level. This is true regardless of storage
     engine.

   * The backup does not include log or configuration files, or other
     database-related files that are not part of databases.

   * Backups stored in logical format are machine independent and
     highly portable.

   * Logical backups are performed with the MySQL server running.  The
     server is not taken offline.

   * Logical backup tools include the *Note `mysqldump': mysqldump.
     program and the *Note `SELECT ... INTO OUTFILE': select.
     statement. These work for any storage engine, even `MEMORY'.

   * To restore logical backups, SQL-format dump files can be processed
     using the *Note `mysql': mysql. client. To load delimited-text
     files, use the *Note `LOAD DATA INFILE': load-data. statement or
     the *Note `mysqlimport': mysqlimport. client.

Physical backup methods have these characteristics:

   * The backup consists of exact copies of database directories and
     files. Typically this is a copy of all or part of the MySQL data
     directory. Data from `MEMORY' tables cannot be backed up this way
     because their contents are not stored on disk.

   * Physical backup methods are faster than logical because they
     involve only file copying without conversion.

   * Output is more compact than for logical backup.

   * Backup and restore granularity ranges from the level of the entire
     data directory down to the level of individual files.  This may or
     may not provide for table-level granularity, depending on storage
     engine. (Each `MyISAM' table corresponds uniquely to a set of
     files, but an `InnoDB' table shares file storage with other
     `InnoDB' tables.)

   * In addition to databases, the backup can include any related files
     such as log or configuration files.

   * Backups are portable only to other machines that have identical or
     similar hardware characteristics.

   * Backups can be performed while the MySQL server is not running. If
     the server is running, it is necessary to perform appropriate
     locking so that the server does not change database contents
     during the backup.

   * Physical backup tools include file system-level commands (such as
     `cp', `scp', `tar', `rsync'), *Note `mysqlhotcopy': mysqlhotcopy.
     for `MyISAM' tables, `ibbackup' for `InnoDB' tables, or `START
     BACKUP' for *Note `NDB': mysql-cluster. tables.

   * For restore, files copied at the file system level or with *Note
     `mysqlhotcopy': mysqlhotcopy. can be copied back to their original
     locations with file system commands; `ibbackup' restores `InnoDB'
     tables, and *Note `ndb_restore':
     mysql-cluster-programs-ndb-restore. restores *Note `NDB':
     mysql-cluster. tables.

*Online Versus Offline Backups*

Online backups take place while the MySQL server is running so that the
database information can be obtained from the server.  Offline backups
take place while the server is stopped. This distinction can also be
described as `hot' versus `cold' backups; a `warm' backup is one where
the server remains running but locked against modifying data while you
access database files externally.

Online backup methods have these characteristics:

   * The backup is less intrusive to other clients, which can connect
     to the MySQL server during the backup and may be able to access
     data depending on what operations they need to perform.

   * Care must be taken to impose appropriate locking so that data
     modifications do not take place that would compromise backup
     integrity.

Offline backup methods have these characteristics:

   * Clients can be affected adversely because the server is
     unavailable during backup.

   * The backup procedure is simpler because there is no possibility of
     interference from client activity.

A similar distinction between online and offline applies for recovery
operations, and similar characteristics apply. However, it is more
likely that clients will be affected for online recovery than for
online backup because recovery requires stronger locking. During
backup, clients might be able to read data while it is being backed up.
Recovery modifies data and does not just read it, so clients must be
prevented from accessing data while it is being restored.

*Local Versus Remote Backups*

A local backup is performed on the same host where the MySQL server
runs, whereas a remote backup is done from a different host. For some
types of backups, the backup can be initiated from a remote host even
if the output is written locally on the server.  host.

   * *Note `mysqldump': mysqldump. can connect to local or remote
     servers. For SQL output (`CREATE' and *Note `INSERT': insert.
     statements), local or remote dumps can be done and generate output
     on the client.  For delimited-text output (with the `--tab'
     option), data files are created on the server host.

   * *Note `mysqlhotcopy': mysqlhotcopy. performs only local backups:
     It connects to the server to lock it against data modifications
     and then copies local table files.

   * *Note `SELECT ... INTO OUTFILE': select-into. can be initiated
     from a local or remote client host, but the output file is created
     on the server host.

   * Physical backup methods typically are initiated locally on the
     MySQL server host so that the server can be taken offline,
     although the destination for copied files might be remote.

*Snapshot Backups*

Some file system implementations enable `snapshots' to be taken. These
provide logical copies of the file system at a given point in time,
without requiring a physical copy of the entire file system. (For
example, the implementation may use copy-on-write techniques so that
only parts of the file system modified after the snapshot time need be
copied.) MySQL itself does not provide the capability for taking file
system snapshots.  It is available through third-party solutions such
as Veritas, LVM, or ZFS.

*Full Versus Incremental Backups*

A full backup includes all data managed by a MySQL server at a given
point in time. An incremental backup consists of the changes made to
the data during a given time span (from one point in time to another).
MySQL has different ways to perform full backups, such as those
described earlier in this section. Incremental backups are made
possible by enabling the server's binary log, which the server uses to
record data changes.

*Full Versus Point-in-Time (Incremental) Recovery*

A full recovery restores all data from a full backup. This restores the
server instance to the state that it had when the backup was made. If
that state is not sufficiently current, a full recovery can be followed
by recovery of incremental backups made since the full backup, to bring
the server to a more up-to-date state.

Incremental recovery is recovery of changes made during a given time
span. This is also called point-in-time recovery because it makes a
server's state current up to a given time. Point-in-time recovery is
based on the binary log and typically follows a full recovery from the
backup files that restores the server to its state when the backup was
made. Then the data changes written in the binary log files are applied
as incremental recovery to redo data modifications and bring the server
up to the desired point in time.

*Table Maintenance*

Data integrity can be compromised if tables become corrupt. MySQL
provides programs for checking *Note `MyISAM': myisam-storage-engine.
tables and repairing them should problems be found. See *Note
myisam-table-maintenance::.

*Backup Scheduling, Compression, and Encryption*

Backup scheduling is valuable for automating backup procedures.
Compression of backup output reduces space requirements, and encryption
of the output provides better security against unauthorized access of
backed-up data. MySQL itself does not provide these capabilities.
`ibbackup' can compress `InnoDB' backups, and compression or encryption
of backup output can be achieved using file system utilities. Other
third-party solutions may be available.


File: manual.info,  Node: backup-methods,  Next: backup-strategy-example,  Prev: backup-types,  Up: backup-and-recovery

7.2 Database Backup Methods
===========================

This section summarizes some general methods for making backups.

*Making Backups by Copying Table Files*

For storage engines that represent each table using its own files,
tables can be backed up by copying those files. For example, `MyISAM'
tables are stored as files, so it is easy to do a backup by copying
files (`*.frm', `*.MYD', and `*.MYI' files).  To get a consistent
backup, stop the server or lock and flush the relevant tables:

     LOCK TABLES TBL_LIST READ;
     FLUSH TABLES TBL_LIST;

You need only a read lock; this enables other clients to continue to
query the tables while you are making a copy of the files in the
database directory. The *Note `FLUSH TABLES': flush.  statement is
needed to ensure that the all active index pages are written to disk
before you start the backup. See *Note lock-tables::, and *Note flush::.

You can also create a binary backup simply by copying all table files,
as long as the server isn't updating anything. The *Note
`mysqlhotcopy': mysqlhotcopy. script uses this method. (But note that
table file copying methods do not work if your database contains
`InnoDB' tables.  *Note `mysqlhotcopy': mysqlhotcopy. does not work for
`InnoDB' tables because `InnoDB' does not necessarily store table
contents in database directories.  Also, even if the server is not
actively updating data, `InnoDB' may still have modified data cached in
memory and not flushed to disk.

*Making Delimited-Text File Backups*

To create a text file containing a table's data, you can use *Note
`SELECT * INTO OUTFILE 'FILE_NAME' FROM TBL_NAME': select-into. The
file is created on the MySQL server host, not the client host. For this
statement, the output file cannot already exist because permitting
files to be overwritten constitutes a security risk. See *Note
select::. This method works for any kind of data file, but saves only
table data, not the table structure.

Another way to create text data files (along with files containing
*Note `CREATE TABLE': create-table. statements for the backed up
tables) is to use *Note `mysqldump': mysqldump. with the `--tab'
option. See *Note mysqldump-delimited-text::.

To reload a delimited-text data file, use *Note `LOAD DATA INFILE':
load-data. or *Note `mysqlimport': mysqlimport.

*Making Backups with *Note `mysqldump': mysqldump. or *Note
`mysqlhotcopy': mysqlhotcopy.*

The *Note `mysqldump': mysqldump. program and the *Note `mysqlhotcopy':
mysqlhotcopy. script can make backups.  *Note `mysqldump': mysqldump.
is more general because it can back up all kinds of tables. *Note
`mysqlhotcopy': mysqlhotcopy. works only with some storage engines.
(See *Note using-mysqldump::, and *Note mysqlhotcopy::.)

For `InnoDB' tables, it is possible to perform an online backup that
takes no locks on tables using the `--single-transaction' option to
*Note `mysqldump': mysqldump. See *Note backup-policy::.

*Making Incremental Backups by Enabling the Binary Log*

MySQL supports incremental backups: You must start the server with the
`--log-bin' option to enable binary logging; see *Note binary-log::.
The binary log files provide you with the information you need to
replicate changes to the database that are made subsequent to the point
at which you performed a backup. At the moment you want to make an
incremental backup (containing all changes that happened since the last
full or incremental backup), you should rotate the binary log by using
*Note `FLUSH LOGS': flush. This done, you need to copy to the backup
location all binary logs which range from the one of the moment of the
last full or incremental backup to the last but one. These binary logs
are the incremental backup; at restore time, you apply them as
explained in *Note point-in-time-recovery::. The next time you do a
full backup, you should also rotate the binary log using *Note `FLUSH
LOGS': flush, *Note `mysqldump --flush-logs': mysqldump, or *Note
`mysqlhotcopy --flushlog': mysqlhotcopy. See *Note mysqldump::, and
*Note mysqlhotcopy::.

*Making Backups Using Replication Slaves*

If you have performance problems with your master server while making
backups, one strategy that can help is to set up replication and
perform backups on the slave rather than on the master. See *Note
replication-solutions-backups::.

If you are backing up a slave replication server, you should back up
its `master.info' and `relay-log.info' files when you back up the
slave's databases, regardless of the backup method you choose.  These
information files are always needed to resume replication after you
restore the slave's data. If your slave is replicating *Note `LOAD DATA
INFILE': load-data. statements, you should also back up any
`SQL_LOAD-*' files that exist in the directory that the slave uses for
this purpose. The slave needs these files to resume replication of any
interrupted *Note `LOAD DATA INFILE': load-data. operations. The
location of this directory is the value of the `--slave-load-tmpdir'
option. If the server was not started with that option, the directory
location is the value of the `tmpdir' system variable.

*Recovering Corrupt Tables*

If you have to restore `MyISAM' tables that have become corrupt, try to
recover them using *Note `REPAIR TABLE': repair-table. or *Note
`myisamchk -r': myisamchk. first. That should work in 99.9% of all
cases. If *Note `myisamchk': myisamchk. fails, see *Note
myisam-table-maintenance::.

*Making Backups Using a File System Snapshot*

If you are using a Veritas file system, you can make a backup like this:

  1. From a client program, execute *Note `FLUSH TABLES WITH READ
     LOCK': flush.

  2. From another shell, execute `mount vxfs snapshot'.

  3. From the first client, execute *Note `UNLOCK TABLES': lock-tables.

  4. Copy files from the snapshot.

  5. Unmount the snapshot.

Similar snapshot capabilities may be available in other file systems,
such as LVM or ZFS.


File: manual.info,  Node: backup-strategy-example,  Next: using-mysqldump,  Prev: backup-methods,  Up: backup-and-recovery

7.3 Example Backup and Recovery Strategy
========================================

* Menu:

* backup-policy::                Establishing a Backup Policy
* recovery-from-backups::        Using Backups for Recovery
* backup-strategy-summary::      Backup Strategy Summary

This section discusses a procedure for performing backups that enables
you to recover data after several types of crashes:

   * Operating system crash

   * Power failure

   * File system crash

   * Hardware problem (hard drive, motherboard, and so forth)

The example commands do not include options such as `--user' and
`--password' for the *Note `mysqldump': mysqldump. and *Note `mysql':
mysql. client programs. You should include such options as necessary to
enable client programs to connect to the MySQL server.

Assume that data is stored in the `InnoDB' storage engine, which has
support for transactions and automatic crash recovery. Assume also that
the MySQL server is under load at the time of the crash. If it were
not, no recovery would ever be needed.

For cases of operating system crashes or power failures, we can assume
that MySQL's disk data is available after a restart. The `InnoDB' data
files might not contain consistent data due to the crash, but `InnoDB'
reads its logs and finds in them the list of pending committed and
noncommitted transactions that have not been flushed to the data files.
`InnoDB' automatically rolls back those transactions that were not
committed, and flushes to its data files those that were committed.
Information about this recovery process is conveyed to the user through
the MySQL error log. The following is an example log excerpt:

     InnoDB: Database was not shut down normally.
     InnoDB: Starting recovery from log files...
     InnoDB: Starting log scan based on checkpoint at
     InnoDB: log sequence number 0 13674004
     InnoDB: Doing recovery: scanned up to log sequence number 0 13739520
     InnoDB: Doing recovery: scanned up to log sequence number 0 13805056
     InnoDB: Doing recovery: scanned up to log sequence number 0 13870592
     InnoDB: Doing recovery: scanned up to log sequence number 0 13936128
     ...
     InnoDB: Doing recovery: scanned up to log sequence number 0 20555264
     InnoDB: Doing recovery: scanned up to log sequence number 0 20620800
     InnoDB: Doing recovery: scanned up to log sequence number 0 20664692
     InnoDB: 1 uncommitted transaction(s) which must be rolled back
     InnoDB: Starting rollback of uncommitted transactions
     InnoDB: Rolling back trx no 16745
     InnoDB: Rolling back of trx no 16745 completed
     InnoDB: Rollback of uncommitted transactions completed
     InnoDB: Starting an apply batch of log records to the database...
     InnoDB: Apply batch completed
     InnoDB: Started
     mysqld: ready for connections

For the cases of file system crashes or hardware problems, we can
assume that the MySQL disk data is _not_ available after a restart.
This means that MySQL fails to start successfully because some blocks
of disk data are no longer readable. In this case, it is necessary to
reformat the disk, install a new one, or otherwise correct the
underlying problem.  Then it is necessary to recover our MySQL data
from backups, which means that backups must already have been made. To
make sure that is the case, design and implement a backup policy.


File: manual.info,  Node: backup-policy,  Next: recovery-from-backups,  Prev: backup-strategy-example,  Up: backup-strategy-example

7.3.1 Establishing a Backup Policy
----------------------------------

To be useful, backups must be scheduled regularly. A full backup (a
snapshot of the data at a point in time) can be done in MySQL with
several tools. For example, `InnoDB Hot Backup' provides online
nonblocking physical backup of the `InnoDB' data files, and *Note
`mysqldump': mysqldump. provides online logical backup.  This
discussion uses *Note `mysqldump': mysqldump.

Assume that we make a full backup of all our `InnoDB' tables in all
databases using the following command on Sunday at 1 p.m., when load is
low:

     shell> mysqldump --single-transaction --all-databases > backup_sunday_1_PM.sql

The resulting `.sql' file produced by *Note `mysqldump': mysqldump.
contains a set of SQL *Note `INSERT': insert. statements that can be
used to reload the dumped tables at a later time.

This backup operation acquires a global read lock on all tables at the
beginning of the dump (using *Note `FLUSH TABLES WITH READ LOCK':
flush.). As soon as this lock has been acquired, the binary log
coordinates are read and the lock is released. If long updating
statements are running when the *Note `FLUSH': flush. statement is
issued, the backup operation may stall until those statements finish.
After that, the dump becomes lock-free and does not disturb reads and
writes on the tables.

It was assumed earlier that the tables to back up are `InnoDB' tables,
so `--single-transaction' uses a consistent read and guarantees that
data seen by *Note `mysqldump': mysqldump. does not change. (Changes
made by other clients to `InnoDB' tables are not seen by the *Note
`mysqldump': mysqldump. process.) If the backup operation includes
nontransactional tables, consistency requires that they do not change
during the backup. For example, for the `MyISAM' tables in the `mysql'
database, there must be no administrative changes to MySQL accounts
during the backup.

Full backups are necessary, but it is not always convenient to create
them. They produce large backup files and take time to generate. They
are not optimal in the sense that each successive full backup includes
all data, even that part that has not changed since the previous full
backup. It is more efficient to make an initial full backup, and then
to make incremental backups. The incremental backups are smaller and
take less time to produce. The tradeoff is that, at recovery time, you
cannot restore your data just by reloading the full backup. You must
also process the incremental backups to recover the incremental changes.

To make incremental backups, we need to save the incremental changes.
In MySQL, these changes are represented in the binary log, so the MySQL
server should always be started with the `--log-bin' option to enable
that log. With binary logging enabled, the server writes each data
change into a file while it updates data. Looking at the data directory
of a MySQL server that was started with the `--log-bin' option and that
has been running for some days, we find these MySQL binary log files:

     -rw-rw---- 1 guilhem  guilhem   1277324 Nov 10 23:59 gbichot2-bin.000001
     -rw-rw---- 1 guilhem  guilhem         4 Nov 10 23:59 gbichot2-bin.000002
     -rw-rw---- 1 guilhem  guilhem        79 Nov 11 11:06 gbichot2-bin.000003
     -rw-rw---- 1 guilhem  guilhem       508 Nov 11 11:08 gbichot2-bin.000004
     -rw-rw---- 1 guilhem  guilhem 220047446 Nov 12 16:47 gbichot2-bin.000005
     -rw-rw---- 1 guilhem  guilhem    998412 Nov 14 10:08 gbichot2-bin.000006
     -rw-rw---- 1 guilhem  guilhem       361 Nov 14 10:07 gbichot2-bin.index

Each time it restarts, the MySQL server creates a new binary log file
using the next number in the sequence. While the server is running, you
can also tell it to close the current binary log file and begin a new
one manually by issuing a *Note `FLUSH LOGS': flush. SQL statement or
with a *Note `mysqladmin flush-logs': mysqladmin.  command. *Note
`mysqldump': mysqldump. also has an option to flush the logs. The
`.index' file in the data directory contains the list of all MySQL
binary logs in the directory.

The MySQL binary logs are important for recovery because they form the
set of incremental backups. If you make sure to flush the logs when you
make your full backup, the binary log files created afterward contain
all the data changes made since the backup. Let's modify the previous
*Note `mysqldump': mysqldump.  command a bit so that it flushes the
MySQL binary logs at the moment of the full backup, and so that the
dump file contains the name of the new current binary log:

     shell> mysqldump --single-transaction --flush-logs --master-data=2 \
              --all-databases > backup_sunday_1_PM.sql

After executing this command, the data directory contains a new binary
log file, `gbichot2-bin.000007', because the `--flush-logs' option
causes the server to flush its logs. The `--master-data' option causes
*Note `mysqldump': mysqldump. to write binary log information to its
output, so the resulting `.sql' dump file includes these lines:

     -- Position to start replication or point-in-time recovery from
     -- CHANGE MASTER TO MASTER_LOG_FILE='gbichot2-bin.000007',MASTER_LOG_POS=4;

Because the *Note `mysqldump': mysqldump. command made a full backup,
those lines mean two things:

   * The dump file contains all changes made before any changes written
     to the `gbichot2-bin.000007' binary log file or newer.

   * All data changes logged after the backup are not present in the
     dump file, but are present in the `gbichot2-bin.000007' binary log
     file or newer.

On Monday at 1 p.m., we can create an incremental backup by flushing
the logs to begin a new binary log file. For example, executing a *Note
`mysqladmin flush-logs': mysqladmin. command creates
`gbichot2-bin.000008'. All changes between the Sunday 1 p.m. full
backup and Monday 1 p.m. will be in the `gbichot2-bin.000007' file. This
incremental backup is important, so it is a good idea to copy it to a
safe place. (For example, back it up on tape or DVD, or copy it to
another machine.) On Tuesday at 1 p.m., execute another *Note
`mysqladmin flush-logs': mysqladmin. command. All changes between
Monday 1 p.m. and Tuesday 1 p.m. will be in the `gbichot2-bin.000008'
file (which also should be copied somewhere safe).

The MySQL binary logs take up disk space. To free up space, purge them
from time to time. One way to do this is by deleting the binary logs
that are no longer needed, such as when we make a full backup:

     shell> mysqldump --single-transaction --flush-logs --master-data=2 \
              --all-databases --delete-master-logs > backup_sunday_1_PM.sql

*Note*:

Deleting the MySQL binary logs with *Note `mysqldump
--delete-master-logs': mysqldump. can be dangerous if your server is a
replication master server, because slave servers might not yet fully
have processed the contents of the binary log.  The description for the
*Note `PURGE BINARY LOGS': purge-binary-logs. statement explains what
should be verified before deleting the MySQL binary logs. See *Note
purge-binary-logs::.


File: manual.info,  Node: recovery-from-backups,  Next: backup-strategy-summary,  Prev: backup-policy,  Up: backup-strategy-example

7.3.2 Using Backups for Recovery
--------------------------------

Now, suppose that we have a catastrophic crash on Wednesday at 8 a.m.
that requires recovery from backups. To recover, first we restore the
last full backup we have (the one from Sunday 1 p.m.). The full backup
file is just a set of SQL statements, so restoring it is very easy:

     shell> mysql < backup_sunday_1_PM.sql

At this point, the data is restored to its state as of Sunday 1 p.m..
To restore the changes made since then, we must use the incremental
backups; that is, the `gbichot2-bin.000007' and `gbichot2-bin.000008'
binary log files. Fetch the files if necessary from where they were
backed up, and then process their contents like this:

     shell> mysqlbinlog gbichot2-bin.000007 gbichot2-bin.000008 | mysql

We now have recovered the data to its state as of Tuesday 1 p.m., but
still are missing the changes from that date to the date of the crash.
To not lose them, we would have needed to have the MySQL server store
its MySQL binary logs into a safe location (RAID disks, SAN, ...)
different from the place where it stores its data files, so that these
logs were not on the destroyed disk. (That is, we can start the server
with a `--log-bin' option that specifies a location on a different
physical device from the one on which the data directory resides. That
way, the logs are safe even if the device containing the directory is
lost.) If we had done this, we would have the `gbichot2-bin.000009'
file (and any subsequent files) at hand, and we could apply them using
*Note `mysqlbinlog': mysqlbinlog. and *Note `mysql': mysql. to restore
the most recent data changes with no loss up to the moment of the crash:

     shell> mysqlbinlog gbichot2-bin.000009 ... | mysql

For more information about using *Note `mysqlbinlog': mysqlbinlog.  to
process binary log files, see *Note point-in-time-recovery::.


File: manual.info,  Node: backup-strategy-summary,  Prev: recovery-from-backups,  Up: backup-strategy-example

7.3.3 Backup Strategy Summary
-----------------------------

In case of an operating system crash or power failure, `InnoDB' itself
does all the job of recovering data. But to make sure that you can
sleep well, observe the following guidelines:

   * Always run the MySQL server with the `--log-bin' option, or even
     `--log-bin=LOG_NAME', where the log file name is located on some
     safe media different from the drive on which the data directory is
     located. If you have such safe media, this technique can also be
     good for disk load balancing (which results in a performance
     improvement).

   * Make periodic full backups, using the *Note `mysqldump':
     mysqldump. command shown earlier in *Note backup-policy::, that
     makes an online, nonblocking backup.

   * Make periodic incremental backups by flushing the logs with *Note
     `FLUSH LOGS': flush.  or *Note `mysqladmin flush-logs': mysqladmin.


File: manual.info,  Node: using-mysqldump,  Next: point-in-time-recovery,  Prev: backup-strategy-example,  Up: backup-and-recovery

7.4 Using `mysqldump' for Backups
=================================

* Menu:

* mysqldump-sql-format::         Dumping Data in SQL Format with `mysqldump'
* reloading-sql-format-dumps::   Reloading SQL-Format Backups
* mysqldump-delimited-text::     Dumping Data in Delimited-Text Format with `mysqldump'
* reloading-delimited-text-dumps::  Reloading Delimited-Text Format Backups
* mysqldump-tips::               `mysqldump' Tips

This section describes how to use *Note `mysqldump': mysqldump. to
produce dump files, and how to reload dump files. A dump file can be
used in several ways:

   * As a backup to enable data recovery in case of data loss.

   * As a source of data for setting up replication slaves.

   * As a source of data for experimentation:

        * To make a copy of a database that you can use without
          changing the original data.

        * To test potential upgrade incompatibilities.

*Note `mysqldump': mysqldump. produces two types of output, depending
on whether the `--tab' option is given:

   * Without `--tab', *Note `mysqldump': mysqldump. writes SQL
     statements to the standard output. This output consists of
     `CREATE' statements to create dumped objects (databases, tables,
     stored routines, and so forth), and `INSERT' statements to load
     data into tables.  The output can be saved in a file and reloaded
     later using *Note `mysql': mysql. to recreate the dumped objects.
     Options are available to modify the format of the SQL statements,
     and to control which objects are dumped.

   * With `--tab', *Note `mysqldump': mysqldump. produces two output
     files for each dumped table. The server writes one file as
     tab-delimited text, one line per table row. This file is named
     `TBL_NAME.txt' in the output directory. The server also sends a
     *Note `CREATE TABLE': create-table. statement for the table to
     *Note `mysqldump': mysqldump, which writes it as a file named
     `TBL_NAME.sql' in the output directory.


File: manual.info,  Node: mysqldump-sql-format,  Next: reloading-sql-format-dumps,  Prev: using-mysqldump,  Up: using-mysqldump

7.4.1 Dumping Data in SQL Format with `mysqldump'
-------------------------------------------------

This section describes how to use *Note `mysqldump': mysqldump.  to
create SQL-format dump files. For information about reloading such dump
files, see *Note reloading-sql-format-dumps::.

By default, *Note `mysqldump': mysqldump. writes information as SQL
statements to the standard output. You can save the output in a file:

     shell> mysqldump [ARGUMENTS] > FILE_NAME

To dump all databases, invoke *Note `mysqldump': mysqldump. with the
`--all-databases' option:

     shell> mysqldump --all-databases > dump.sql

To dump only specific databases, name them on the command line and use
the `--databases' option:

     shell> mysqldump --databases db1 db2 db3 > dump.sql

The `--databases' option causes all names on the command line to be
treated as database names.  Without this option, *Note `mysqldump':
mysqldump. treats the first name as a database name and those following
as table names.

With `--all-databases' or `--databases', *Note `mysqldump': mysqldump.
writes *Note `CREATE DATABASE': create-database. and *Note `USE': use.
statements prior to the dump output for each database. This ensures
that when the dump file is reloaded, it creates each database if it
does not exist and makes it the default database so database contents
are loaded into the same database from which they came. If you want to
cause the dump file to force a drop of each database before recreating
it, use the `--add-drop-database' option as well. In this case, *Note
`mysqldump': mysqldump. writes a *Note `DROP DATABASE': drop-database.
statement preceding each *Note `CREATE DATABASE': create-database.
statement.

To dump a single database, name it on the command line:

     shell> mysqldump --databases test > dump.sql

In the single-database case, it is permissible to omit the
`--databases' option:

     shell> mysqldump test > dump.sql

The difference between the two preceding commands is that without
`--databases', the dump output contains no *Note `CREATE DATABASE':
create-database. or *Note `USE': use.  statements. This has several
implications:

   * When you reload the dump file, you must specify a default database
     name so that the server knows which database to reload.

   * For reloading, you can specify a database name different from the
     original name, which enables you to reload the data into a
     different database.

   * If the database to be reloaded does not exist, you must create it
     first.

   * Because the output will contain no *Note `CREATE DATABASE':
     create-database. statement, the `--add-drop-database' option has
     no effect. If you use it, it produces no *Note `DROP DATABASE':
     drop-database. statement.

To dump only specific tables from a database, name them on the command
line following the database name:

     shell> mysqldump test t1 t3 t7 > dump.sql


File: manual.info,  Node: reloading-sql-format-dumps,  Next: mysqldump-delimited-text,  Prev: mysqldump-sql-format,  Up: using-mysqldump

7.4.2 Reloading SQL-Format Backups
----------------------------------

To reload a dump file written by *Note `mysqldump': mysqldump.  that
consists of SQL statements, use it as input to the *Note `mysql':
mysql. client. If the dump file was created by *Note `mysqldump':
mysqldump. with the `--all-databases' or `--databases' option, it
contains *Note `CREATE DATABASE': create-database. and *Note `USE':
use. statements and it is not necessary to specify a default database
into which to load the data:

     shell> mysql < dump.sql

Alternatively, from within *Note `mysql': mysql, use a `source' command:

     mysql> source dump.sql

If the file is a single-database dump not containing *Note `CREATE
DATABASE': create-database. and *Note `USE': use. statements, create the
database first (if necessary):

     shell> mysqladmin create db1

Then specify the database name when you load the dump file:

     shell> mysql db1 < dump.sql

Alternatively, from within *Note `mysql': mysql, create the database,
select it as the default database, and load the dump file:

     mysql> CREATE DATABASE IF NOT EXISTS db1;
     mysql> USE db1;
     mysql> source dump.sql


File: manual.info,  Node: mysqldump-delimited-text,  Next: reloading-delimited-text-dumps,  Prev: reloading-sql-format-dumps,  Up: using-mysqldump

7.4.3 Dumping Data in Delimited-Text Format with `mysqldump'
------------------------------------------------------------

This section describes how to use *Note `mysqldump': mysqldump.  to
create delimited-text dump files. For information about reloading such
dump files, see *Note reloading-delimited-text-dumps::.

If you invoke *Note `mysqldump': mysqldump. with the `--tab=DIR_NAME'
option, it uses DIR_NAME as the output directory and dumps tables
individually in that directory using two files for each table. The
table name is the basename for these files. For a table named `t1', the
files are named `t1.sql' and `t1.txt'. The `.sql' file contains a *Note
`CREATE TABLE': create-table. statement for the table. The `.txt' file
contains the table data, one line per table row.

The following command dumps the contents of the `db1' database to files
in the `/tmp' database:

     shell> mysqldump --tab=/tmp db1

The `.txt' files containing table data are written by the server, so
they are owned by the system account used for running the server. The
server uses *Note `SELECT ... INTO OUTFILE': select-into. to write the
files, so you must have the `FILE' privilege to perform this operation,
and an error occurs if a given `.txt' file already exists.

The server sends the `CREATE' definitions for dumped tables to *Note
`mysqldump': mysqldump, which writes them to `.sql' files. These files
therefore are owned by the user who executes *Note `mysqldump':
mysqldump.

It is best that `--tab' be used only for dumping a local server. If you
use it with a remote server, the `--tab' directory must exist on both
the local and remote hosts, and the `.txt' files will be written by the
server in the remote directory (on the server host), whereas the `.sql'
files will be written by *Note `mysqldump': mysqldump. in the local
directory (on the client host).

For *Note `mysqldump --tab': mysqldump, the server by default writes
table data to `.txt' files one line per row with tabs between column
values, no quotation marks around column values, and newline as the
line terminator. (These are the same defaults as for *Note `SELECT ...
INTO OUTFILE': select-into.)

To enable data files to be written using a different format, *Note
`mysqldump': mysqldump. supports these options:

   * `--fields-terminated-by=STR'

     The string for separating column values (default: tab).

   * `--fields-enclosed-by=CHAR'

     The character within which to enclose column values (default: no
     character).

   * `--fields-optionally-enclosed-by=CHAR'

     The character within which to enclose non-numeric column values
     (default: no character).

   * `--fields-escaped-by=CHAR'

     The character for escaping special characters (default: no
     escaping).

   * `--lines-terminated-by=STR'

     The line-termination string (default: newline).

Depending on the value you specify for any of these options, it might
be necessary on the command line to quote or escape the value
appropriately for your command interpreter. Alternatively, specify the
value using hex notation. Suppose that you want *Note `mysqldump':
mysqldump. to quote column values within double quotation marks. To do
so, specify double quote as the value for the `--fields-enclosed-by'
option. But this character is often special to command interpreters and
must be treated specially. For example, on Unix, you can quote the
double quote like this:

     --fields-enclosed-by='"'

On any platform, you can specify the value in hex:

     --fields-enclosed-by=0x22

It is common to use several of the data-formatting options together.
For example, to dump tables in comma-separated values format with lines
terminated by carriage-return/newline pairs (`\r\n'), use this command
(enter it on a single line):

     shell> mysqldump --tab=/tmp --fields-terminated-by=,
              --fields-enclosed-by='"' --lines-terminated-by=0x0d0a db1

Should you use any of the data-formatting options to dump table data,
you will need to specify the same format when you reload data files
later, to ensure proper interpretation of the file contents.


File: manual.info,  Node: reloading-delimited-text-dumps,  Next: mysqldump-tips,  Prev: mysqldump-delimited-text,  Up: using-mysqldump

7.4.4 Reloading Delimited-Text Format Backups
---------------------------------------------

For backups produced with *Note `mysqldump --tab': mysqldump, each
table is represented in the output directory by an `.sql' file
containing the *Note `CREATE TABLE': create-table. statement for the
table, and a `.txt' file containing the table data. To reload a table,
first change location into the output directory. Then process the
`.sql' file with *Note `mysql': mysql. to create an empty table and
process the `.txt' file to load the data into the table:

     shell> mysql db1 < t1.sql
     shell> mysqlimport db1 t1.txt

An alternative to using *Note `mysqlimport': mysqlimport. to load the
data file is to use the *Note `LOAD DATA INFILE': load-data. statement
from within the *Note `mysql': mysql. client:

     mysql> USE db1;
     mysql> LOAD DATA INFILE 't1.txt' INTO TABLE t1;

If you used any data-formatting options with *Note `mysqldump':
mysqldump. when you initially dumped the table, you must use the same
options with *Note `mysqlimport': mysqlimport. or *Note `LOAD DATA
INFILE': load-data. to ensure proper interpretation of the data file
contents:

     shell> mysqlimport --fields-terminated-by=,
              --fields-enclosed-by='"' --lines-terminated-by=0x0d0a db1 t1.txt

Or:

     mysql> USE db1;
     mysql> LOAD DATA INFILE 't1.txt' INTO TABLE t1
         -> FIELDS TERMINATED BY ',' FIELDS ENCLOSED BY '"'
         -> LINES TERMINATED BY '\r\n';


File: manual.info,  Node: mysqldump-tips,  Prev: reloading-delimited-text-dumps,  Up: using-mysqldump

7.4.5 `mysqldump' Tips
----------------------

* Menu:

* mysqldump-copying-database::   Making a Copy of a Database
* mysqldump-copying-to-other-server::  Copy a Database from one Server to Another
* mysqldump-stored-programs::    Dumping Stored Programs
* mysqldump-definition-data-dumps::  Dumping Table Definitions and Content Separately
* mysqldump-upgrade-testing::    Using `mysqldump' to Test for Upgrade Incompatibilities

This section surveys techniques that enable you to use *Note
`mysqldump': mysqldump. to solve specific problems:

   * How to make a copy a database

   * How to copy a database from one server to another

   * How to dump stored programs (stored procedures and functions and
     triggers)

   * How to dump definitions and data separately


File: manual.info,  Node: mysqldump-copying-database,  Next: mysqldump-copying-to-other-server,  Prev: mysqldump-tips,  Up: mysqldump-tips

7.4.5.1 Making a Copy of a Database
...................................

     shell> mysqldump db1 > dump.sql
     shell> mysqladmin create db2
     shell> mysql db2 < dump.sql

Do not use `--databases' on the *Note `mysqldump': mysqldump. command
line because that causes `USE db1' to be included in the dump file,
which overrides the effect of naming `db2' on the *Note `mysql': mysql.
command line.


File: manual.info,  Node: mysqldump-copying-to-other-server,  Next: mysqldump-stored-programs,  Prev: mysqldump-copying-database,  Up: mysqldump-tips

7.4.5.2 Copy a Database from one Server to Another
..................................................

On Server 1:

     shell> mysqldump --databases db1 > dump.sql

Copy the dump file from Server 1 to Server 2.

On Server 2:

     shell> mysql < dump.sql

Use of `--databases' with the *Note `mysqldump': mysqldump. command
line causes the dump file to include *Note `CREATE DATABASE':
create-database. and *Note `USE': use. statements that create the
database if it does exist and make it the default database for the
reloaded data.

Alternatively, you can omit `--databases' from the *Note `mysqldump':
mysqldump. command. Then you will need to create the database on Server
2 (if necessary) and specify it as the default database when you reload
the dump file.

On Server 1:

     shell> mysqldump db1 > dump.sql

On Server 2:

     shell> mysqladmin create db1
     shell> mysql db1 < dump.sql

You can specify a different database name in this case, so omitting
`--databases' from the *Note `mysqldump': mysqldump. command enables
you to dump data from one database and load it into another.


File: manual.info,  Node: mysqldump-stored-programs,  Next: mysqldump-definition-data-dumps,  Prev: mysqldump-copying-to-other-server,  Up: mysqldump-tips

7.4.5.3 Dumping Stored Programs
...............................

Several options control how *Note `mysqldump': mysqldump.  handles
stored programs (stored procedures and functions and triggers):

   * `--routines': Dump stored procedures and functions

   * `--triggers': Dump triggers for tables

The `--triggers' option is enabled by default so that when tables are
dumped, they are accompanied by any triggers they have. The other
options are disabled by default and must be specified explicitly to dump
the corresponding objects. To disable any of these options explicitly,
use its skip form: `--skip-routines' or `--skip-triggers'.


File: manual.info,  Node: mysqldump-definition-data-dumps,  Next: mysqldump-upgrade-testing,  Prev: mysqldump-stored-programs,  Up: mysqldump-tips

7.4.5.4 Dumping Table Definitions and Content Separately
........................................................

The `--no-data' option tells *Note `mysqldump': mysqldump. not to dump
table data, resulting in the dump file containing only statements to
create the tables. Conversely, the `--no-create-info' option tells
*Note `mysqldump': mysqldump. to suppress `CREATE' statements from the
output, so that the dump file contains only table data.

For example, to dump table definitions and data separately for the
`test' database, use these commands:

     shell> mysqldump --no-data test > dump-defs.sql
     shell> mysqldump --no-create-info test > dump-data.sql

For a definition-only dump, add the `--routines' option to also include
stored routine definitions:

     shell> mysqldump --no-data --routines test > dump-defs.sql


File: manual.info,  Node: mysqldump-upgrade-testing,  Prev: mysqldump-definition-data-dumps,  Up: mysqldump-tips

7.4.5.5 Using `mysqldump' to Test for Upgrade Incompatibilities
...............................................................

When contemplating a MySQL upgrade, it is prudent to install the newer
version separately from your current production version. Then you can
dump the database and database object definitions from the production
server and load them into the new server to verify that they are
handled properly. (This is also useful for testing downgrades.)

On the production server:

     shell> mysqldump --all-databases --no-data --routines > dump-defs.sql

On the upgraded server:

     shell> mysql < dump-defs.sql

Because the dump file does not contain table data, it can be processed
quickly. This enables you to spot potential incompatibilities without
waiting for lengthy data-loading operations. Look for warnings or
errors while the dump file is being processed.

After you have verified that the definitions are handled properly, dump
the data and try to load it into the upgraded server.

On the production server:

     shell> mysqldump --all-databases --no-create-info > dump-data.sql

On the upgraded server:

     shell> mysql < dump-data.sql

Now check the table contents and run some test queries.


File: manual.info,  Node: point-in-time-recovery,  Next: myisam-table-maintenance,  Prev: using-mysqldump,  Up: backup-and-recovery

7.5 Point-in-Time (Incremental) Recovery Using the Binary Log
=============================================================

* Menu:

* point-in-time-recovery-times::  Point-in-Time Recovery Using Event Times
* point-in-time-recovery-positions::  Point-in-Time Recovery Using Event Positions

Point-in-time recovery refers to recovery of data changes made since a
given point in time. Typically, this type of recovery is performed
after restoring a full backup that brings the server to its state as of
the time the backup was made. (The full backup can be made in several
ways, such as those listed in *Note backup-methods::.) Point-in-time
recovery then brings the server up to date incrementally from the time
of the full backup to a more recent time.

Point-in-time recovery is based on these principles:

   * The source of information for point-in-time recovery is the set of
     incremental backups represented by the binary log files generated
     subsequent to the full backup operation. Therefore, the server
     must be started with the `--log-bin' option to enable binary
     logging (see *Note binary-log::).

     To restore data from the binary log, you must know the name and
     location of the current binary log files. By default, the server
     creates binary log files in the data directory, but a path name
     can be specified with the `--log-bin' option to place the files in
     a different location. *Note binary-log::.

     To see a listing of all binary log files, use this statement:

          mysql> SHOW BINARY LOGS;

     To determine the name of the current binary log file, issue the
     following statement:

          mysql> SHOW MASTER STATUS;

   * The *Note `mysqlbinlog': mysqlbinlog. utility converts the events
     in the binary log files from binary format to text so that they
     can be executed or viewed. *Note `mysqlbinlog': mysqlbinlog.  has
     options for selecting sections of the binary log based on event
     times or position of events within the log. See *Note
     mysqlbinlog::.

   * Executing events from the binary log causes the data modifications
     they represent to be redone. This enables recovery of data changes
     for a given span of time. To execute events from the binary log,
     process *Note `mysqlbinlog': mysqlbinlog. output using the *Note
     `mysql': mysql. client:

          shell> mysqlbinlog BINLOG_FILES | mysql -u root -p

   * Viewing log contents can be useful when you need to determine
     event times or positions to select partial log contents prior to
     executing events. To view events from the log, send *Note
     `mysqlbinlog': mysqlbinlog. output into a paging program:

          shell> mysqlbinlog BINLOG_FILES | more

     Alternatively, save the output in a file and view the file in a
     text editor:

          shell> mysqlbinlog BINLOG_FILES > tmpfile
          shell> ... EDIT TMPFILE ...

   * Saving the output in a file is useful as a preliminary to
     executing the log contents with certain events removed, such as an
     accidental *Note `DROP DATABASE': drop-database.  You can delete
     from the file any statements not to be executed before executing
     its contents. After editing the file, execute the contents as
     follows:

          shell> mysql -u root -p < tmpfile

If you have more than one binary log to execute on the MySQL server,
the safe method is to process them all using a single connection to the
server. Here is an example that demonstrates what may be _unsafe_:

     shell> mysqlbinlog binlog.000001 | mysql -u root -p # DANGER!!
     shell> mysqlbinlog binlog.000002 | mysql -u root -p # DANGER!!

Processing binary logs this way using different connections to the
server causes problems if the first log file contains a *Note `CREATE
TEMPORARY TABLE': create-table. statement and the second log contains a
statement that uses the temporary table. When the first *Note `mysql':
mysql. process terminates, the server drops the temporary table. When
the second *Note `mysql': mysql. process attempts to use the table, the
server reports `unknown table.'

To avoid problems like this, use a _single_ connection to execute the
contents of all binary logs that you want to process. Here is one way
to do so:

     shell> mysqlbinlog binlog.000001 binlog.000002 | mysql -u root -p

Another approach is to write all the logs to a single file and then
process the file:

     shell> mysqlbinlog binlog.000001 >  /tmp/statements.sql
     shell> mysqlbinlog binlog.000002 >> /tmp/statements.sql
     shell> mysql -u root -p -e "source /tmp/statements.sql"


File: manual.info,  Node: point-in-time-recovery-times,  Next: point-in-time-recovery-positions,  Prev: point-in-time-recovery,  Up: point-in-time-recovery

7.5.1 Point-in-Time Recovery Using Event Times
----------------------------------------------

To indicate the start and end times for recovery, specify the
`--start-datetime' and `--stop-datetime' options for *Note
`mysqlbinlog': mysqlbinlog, in *Note `DATETIME': datetime. format. As
an example, suppose that exactly at 10:00 a.m. on April 20, 2005 an SQL
statement was executed that deleted a large table. To restore the table
and data, you could restore the previous night's backup, and then
execute the following command:

     shell> mysqlbinlog --stop-datetime="2005-04-20 9:59:59" \
              /var/log/mysql/bin.123456 | mysql -u root -p

This command recovers all of the data up until the date and time given
by the `--stop-datetime' option. If you did not detect the erroneous
SQL statement that was entered until hours later, you will probably
also want to recover the activity that occurred afterward. Based on
this, you could run *Note `mysqlbinlog': mysqlbinlog. again with a
start date and time, like so:

     shell> mysqlbinlog --start-datetime="2005-04-20 10:01:00" \
              /var/log/mysql/bin.123456 | mysql -u root -p

In this command, the SQL statements logged from 10:01 a.m. on will be
re-executed. The combination of restoring of the previous night's dump
file and the two *Note `mysqlbinlog': mysqlbinlog. commands restores
everything up until one second before 10:00 a.m. and everything from
10:01 a.m. on.

To use this method of point-in-time recovery, you should examine the
log to be sure of the exact times to specify for the commands. To
display the log file contents without executing them, use this command:

     shell> mysqlbinlog /var/log/mysql/bin.123456 > /tmp/mysql_restore.sql

Then open the `/tmp/mysql_restore.sql' file with a text editor to
examine it.

Excluding specific changes by specifying times for *Note `mysqlbinlog':
mysqlbinlog. does not work well if multiple statements executed at the
same time as the one to be excluded.


File: manual.info,  Node: point-in-time-recovery-positions,  Prev: point-in-time-recovery-times,  Up: point-in-time-recovery

7.5.2 Point-in-Time Recovery Using Event Positions
--------------------------------------------------

Instead of specifying dates and times, the `--start-position' and
`--stop-position' options for *Note `mysqlbinlog': mysqlbinlog. can be
used for specifying log positions. They work the same as the start and
stop date options, except that you specify log position numbers rather
than dates. Using positions may enable you to be more precise about
which part of the log to recover, especially if many transactions
occurred around the same time as a damaging SQL statement. To determine
the position numbers, run *Note `mysqlbinlog': mysqlbinlog. for a range
of times near the time when the unwanted transaction was executed, but
redirect the results to a text file for examination. This can be done
like so:

     shell> mysqlbinlog --start-datetime="2005-04-20 9:55:00" \
              --stop-datetime="2005-04-20 10:05:00" \
              /var/log/mysql/bin.123456 > /tmp/mysql_restore.sql

This command creates a small text file in the `/tmp' directory that
contains the SQL statements around the time that the deleterious SQL
statement was executed. Open this file with a text editor and look for
the statement that you do not want to repeat. Determine the positions
in the binary log for stopping and resuming the recovery and make note
of them. Positions are labeled as `log_pos' followed by a number. After
restoring the previous backup file, use the position numbers to process
the binary log file. For example, you would use commands something like
these:

     shell> mysqlbinlog --stop-position=368312 /var/log/mysql/bin.123456 \
              | mysql -u root -p

     shell> mysqlbinlog --start-position=368315 /var/log/mysql/bin.123456 \
              | mysql -u root -p

The first command recovers all the transactions up until the stop
position given. The second command recovers all transactions from the
starting position given until the end of the binary log. Because the
output of *Note `mysqlbinlog': mysqlbinlog. includes `SET TIMESTAMP'
statements before each SQL statement recorded, the recovered data and
related MySQL logs will reflect the original times at which the
transactions were executed.


File: manual.info,  Node: myisam-table-maintenance,  Prev: point-in-time-recovery,  Up: backup-and-recovery

7.6 `MyISAM' Table Maintenance and Crash Recovery
=================================================

* Menu:

* myisam-crash-recovery::        Using `myisamchk' for Crash Recovery
* myisam-check::                 How to Check `MyISAM' Tables for Errors
* myisam-repair::                How to Repair `MyISAM' Tables
* myisam-optimization::          `MyISAM' Table Optimization
* myisam-maintenance-schedule::  Setting Up a `MyISAM' Table Maintenance Schedule

This section discusses how to use *Note `myisamchk': myisamchk. to
check or repair `MyISAM' tables (tables that have `.MYD' and `.MYI'
files for storing data and indexes). For general *Note `myisamchk':
myisamchk. background, see *Note myisamchk::. Other table-repair
information can be found at *Note rebuilding-tables::.

You can use *Note `myisamchk': myisamchk. to check, repair, or optimize
database tables. The following sections describe how to perform these
operations and how to set up a table maintenance schedule. For
information about using *Note `myisamchk': myisamchk.  to get
information about your tables, see *Note myisamchk-table-info::.

Even though table repair with *Note `myisamchk': myisamchk. is quite
secure, it is always a good idea to make a backup _before_ doing a
repair or any maintenance operation that could make a lot of changes to
a table.

*Note `myisamchk': myisamchk. operations that affect indexes can cause
`FULLTEXT' indexes to be rebuilt with full-text parameters that are
incompatible with the values used by the MySQL server. To avoid this
problem, follow the guidelines in *Note myisamchk-general-options::.

`MyISAM' table maintenance can also be done using the SQL statements
that perform operations similar to what *Note `myisamchk': myisamchk.
can do:

   * To check `MyISAM' tables, use *Note `CHECK TABLE': check-table.

   * To repair `MyISAM' tables, use *Note `REPAIR TABLE': repair-table.

   * To optimize `MyISAM' tables, use *Note `OPTIMIZE TABLE':
     optimize-table.

   * To analyze `MyISAM' tables, use *Note `ANALYZE TABLE':
     analyze-table.

For additional information about these statements, see *Note
table-maintenance-sql::.

These statements can be used directly or by means of the *Note
`mysqlcheck': mysqlcheck. client program. One advantage of these
statements over *Note `myisamchk': myisamchk. is that the server does
all the work. With *Note `myisamchk': myisamchk, you must make sure
that the server does not use the tables at the same time so that there
is no unwanted interaction between *Note `myisamchk': myisamchk. and
the server.


File: manual.info,  Node: myisam-crash-recovery,  Next: myisam-check,  Prev: myisam-table-maintenance,  Up: myisam-table-maintenance

7.6.1 Using `myisamchk' for Crash Recovery
------------------------------------------

This section describes how to check for and deal with data corruption
in MySQL databases. If your tables become corrupted frequently, you
should try to find the reason why. See *Note crashing::.

For an explanation of how `MyISAM' tables can become corrupted, see
*Note myisam-table-problems::.

If you run *Note `mysqld': mysqld. with external locking disabled
(which is the default), you cannot reliably use *Note `myisamchk':
myisamchk. to check a table when *Note `mysqld': mysqld. is using the
same table. If you can be certain that no one will access the tables
through *Note `mysqld': mysqld. while you run *Note `myisamchk':
myisamchk, you only have to execute *Note `mysqladmin flush-tables':
mysqladmin. before you start checking the tables. If you cannot
guarantee this, you must stop *Note `mysqld': mysqld. while you check
the tables. If you run *Note `myisamchk': myisamchk. to check tables
that *Note `mysqld': mysqld. is updating at the same time, you may get
a warning that a table is corrupt even when it is not.

If the server is run with external locking enabled, you can use *Note
`myisamchk': myisamchk. to check tables at any time. In this case, if
the server tries to update a table that *Note `myisamchk': myisamchk.
is using, the server will wait for *Note `myisamchk': myisamchk. to
finish before it continues.

If you use *Note `myisamchk': myisamchk. to repair or optimize tables,
you _must_ always ensure that the *Note `mysqld': mysqld. server is not
using the table (this also applies if external locking is disabled). If
you do not stop *Note `mysqld': mysqld, you should at least do a *Note
`mysqladmin flush-tables': mysqladmin. before you run *Note
`myisamchk': myisamchk. Your tables _may become corrupted_ if the
server and *Note `myisamchk': myisamchk. access the tables
simultaneously.

When performing crash recovery, it is important to understand that each
`MyISAM' table TBL_NAME in a database corresponds to the three files in
the database directory shown in the following table.

File           Purpose
`TBL_NAME.frm' Definition (format) file
`TBL_NAME.MYD' Data file
`TBL_NAME.MYI' Index file

Each of these three file types is subject to corruption in various
ways, but problems occur most often in data files and index files.

*Note `myisamchk': myisamchk. works by creating a copy of the `.MYD'
data file row by row. It ends the repair stage by removing the old
`.MYD' file and renaming the new file to the original file name. If you
use `--quick', *Note `myisamchk': myisamchk. does not create a temporary
`.MYD' file, but instead assumes that the `.MYD' file is correct and
generates only a new index file without touching the `.MYD' file. This
is safe, because *Note `myisamchk': myisamchk.  automatically detects
whether the `.MYD' file is corrupt and aborts the repair if it is. You
can also specify the `--quick' option twice to *Note `myisamchk':
myisamchk. In this case, *Note `myisamchk': myisamchk. does not abort
on some errors (such as duplicate-key errors) but instead tries to
resolve them by modifying the `.MYD' file. Normally the use of two
`--quick' options is useful only if you have too little free disk space
to perform a normal repair. In this case, you should at least make a
backup of the table before running *Note `myisamchk': myisamchk.


File: manual.info,  Node: myisam-check,  Next: myisam-repair,  Prev: myisam-crash-recovery,  Up: myisam-table-maintenance

7.6.2 How to Check `MyISAM' Tables for Errors
---------------------------------------------

To check a `MyISAM' table, use the following commands:

   * *Note `myisamchk TBL_NAME': myisamchk.

     This finds 99.99% of all errors. What it cannot find is corruption
     that involves _only_ the data file (which is very unusual). If you
     want to check a table, you should normally run *Note `myisamchk':
     myisamchk. without options or with the `-s' (silent) option.

   * *Note `myisamchk -m TBL_NAME': myisamchk.

     This finds 99.999% of all errors. It first checks all index
     entries for errors and then reads through all rows. It calculates
     a checksum for all key values in the rows and verifies that the
     checksum matches the checksum for the keys in the index tree.

   * *Note `myisamchk -e TBL_NAME': myisamchk.

     This does a complete and thorough check of all data (`-e' means
     `extended check').  It does a check-read of every key for each row
     to verify that they indeed point to the correct row. This may take
     a long time for a large table that has many indexes. Normally,
     *Note `myisamchk': myisamchk. stops after the first error it
     finds. If you want to obtain more information, you can add the
     `-v' (verbose) option. This causes *Note `myisamchk': myisamchk.
     to keep going, up through a maximum of 20 errors.

   * *Note `myisamchk -e -i TBL_NAME': myisamchk.

     This is like the previous command, but the `-i' option tells *Note
     `myisamchk': myisamchk. to print additional statistical
     information.

In most cases, a simple *Note `myisamchk': myisamchk. command with no
arguments other than the table name is sufficient to check a table.


File: manual.info,  Node: myisam-repair,  Next: myisam-optimization,  Prev: myisam-check,  Up: myisam-table-maintenance

7.6.3 How to Repair `MyISAM' Tables
-----------------------------------

The discussion in this section describes how to use *Note `myisamchk':
myisamchk. on `MyISAM' tables (extensions `.MYI' and `.MYD').

You can also use the *Note `CHECK TABLE': check-table.  and *Note
`REPAIR TABLE': repair-table. statements to check and repair `MyISAM'
tables. See *Note check-table::, and *Note repair-table::.

Symptoms of corrupted tables include queries that abort unexpectedly
and observable errors such as these:

   * `TBL_NAME.frm' is locked against change

   * Can't find file `TBL_NAME.MYI' (Errcode: NNN)

   * Unexpected end of file

   * Record file is crashed

   * Got error NNN from table handler

To get more information about the error, run *Note `perror': perror.
NNN, where NNN is the error number. The following example shows how to
use *Note `perror': perror. to find the meanings for the most common
error numbers that indicate a problem with a table:

     shell> perror 126 127 132 134 135 136 141 144 145
     MySQL error code 126 = Index file is crashed
     MySQL error code 127 = Record-file is crashed
     MySQL error code 132 = Old database file
     MySQL error code 134 = Record was already deleted (or record file crashed)
     MySQL error code 135 = No more room in record file
     MySQL error code 136 = No more room in index file
     MySQL error code 141 = Duplicate unique key or constraint on write or update
     MySQL error code 144 = Table is crashed and last repair failed
     MySQL error code 145 = Table was marked as crashed and should be repaired

Note that error 135 (no more room in record file) and error 136 (no
more room in index file) are not errors that can be fixed by a simple
repair. In this case, you must use *Note `ALTER TABLE': alter-table. to
increase the `MAX_ROWS' and `AVG_ROW_LENGTH' table option values:

     ALTER TABLE TBL_NAME MAX_ROWS=XXX AVG_ROW_LENGTH=YYY;

If you do not know the current table option values, use *Note `SHOW
CREATE TABLE': show-create-table.

For the other errors, you must repair your tables.  *Note `myisamchk':
myisamchk. can usually detect and fix most problems that occur.

The repair process involves up to four stages, described here.  Before
you begin, you should change location to the database directory and
check the permissions of the table files. On Unix, make sure that they
are readable by the user that *Note `mysqld': mysqld. runs as (and to
you, because you need to access the files you are checking). If it
turns out you need to modify files, they must also be writable by you.

This section is for the cases where a table check fails (such as those
described in *Note myisam-check::), or you want to use the extended
features that *Note `myisamchk': myisamchk.  provides.

The *Note `myisamchk': myisamchk. options used for table maintenance
with are described in *Note myisamchk::.  *Note `myisamchk': myisamchk.
also has variables that you can set to control memory allocation that
may improve performance. See *Note myisamchk-memory::.

If you are going to repair a table from the command line, you must
first stop the *Note `mysqld': mysqld. server. Note that when you do
*Note `mysqladmin shutdown': mysqladmin. on a remote server, the *Note
`mysqld': mysqld. server is still available for a while after *Note
`mysqladmin': mysqladmin. returns, until all statement-processing has
stopped and all index changes have been flushed to disk.

*Stage 1: Checking your tables*

Run *Note `myisamchk *.MYI': myisamchk. or *Note `myisamchk -e *.MYI':
myisamchk. if you have more time. Use the `-s' (silent) option to
suppress unnecessary information.

If the *Note `mysqld': mysqld. server is stopped, you should use the
`--update-state' option to tell *Note `myisamchk': myisamchk. to mark
the table as `checked.'

You have to repair only those tables for which *Note `myisamchk':
myisamchk. announces an error. For such tables, proceed to Stage 2.

If you get unexpected errors when checking (such as `out of memory'
errors), or if *Note `myisamchk': myisamchk.  crashes, go to Stage 3.

*Stage 2: Easy safe repair*

First, try *Note `myisamchk -r -q TBL_NAME': myisamchk. (`-r -q' means
`quick recovery mode'). This attempts to repair the index file without
touching the data file. If the data file contains everything that it
should and the delete links point at the correct locations within the
data file, this should work, and the table is fixed. Start repairing
the next table. Otherwise, use the following procedure:

  1. Make a backup of the data file before continuing.

  2. Use *Note `myisamchk -r TBL_NAME': myisamchk.  (`-r' means
     `recovery mode').  This removes incorrect rows and deleted rows
     from the data file and reconstructs the index file.

  3. If the preceding step fails, use *Note `myisamchk --safe-recover
     TBL_NAME': myisamchk. Safe recovery mode uses an old recovery
     method that handles a few cases that regular recovery mode does
     not (but is slower).

*Note*:

If you want a repair operation to go much faster, you should set the
values of the `sort_buffer_size' and `key_buffer_size' variables each
to about 25% of your available memory when running *Note `myisamchk':
myisamchk.

If you get unexpected errors when repairing (such as `out of memory'
errors), or if *Note `myisamchk': myisamchk. crashes, go to Stage 3.

*Stage 3: Difficult repair*

You should reach this stage only if the first 16KB block in the index
file is destroyed or contains incorrect information, or if the index
file is missing. In this case, it is necessary to create a new index
file. Do so as follows:

  1. Move the data file to a safe place.

  2. Use the table description file to create new (empty) data and
     index files:

          shell> mysql DB_NAME
          mysql> SET autocommit=1;
          mysql> TRUNCATE TABLE TBL_NAME;
          mysql> quit

  3. Copy the old data file back onto the newly created data file. (Do
     not just move the old file back onto the new file.  You want to
     retain a copy in case something goes wrong.)

*Important*:

If you are using replication, you should stop it prior to performing
the above procedure, since it involves file system operations, and
these are not logged by MySQL.

Go back to Stage 2. *Note `myisamchk -r -q': myisamchk. should work.
(This should not be an endless loop.)

You can also use the `REPAIR TABLE TBL_NAME USE_FRM' SQL statement,
which performs the whole procedure automatically.  There is also no
possibility of unwanted interaction between a utility and the server,
because the server does all the work when you use *Note `REPAIR TABLE':
repair-table. See *Note repair-table::.

*Stage 4: Very difficult repair*

You should reach this stage only if the `.frm' description file has
also crashed.  That should never happen, because the description file
is not changed after the table is created:

  1. Restore the description file from a backup and go back to Stage 3.
     You can also restore the index file and go back to Stage 2. In the
     latter case, you should start with *Note `myisamchk -r': myisamchk.

  2. If you do not have a backup but know exactly how the table was
     created, create a copy of the table in another database.  Remove
     the new data file, and then move the `.frm' description and `.MYI'
     index files from the other database to your crashed database. This
     gives you new description and index files, but leaves the `.MYD'
     data file alone. Go back to Stage 2 and attempt to reconstruct the
     index file.


File: manual.info,  Node: myisam-optimization,  Next: myisam-maintenance-schedule,  Prev: myisam-repair,  Up: myisam-table-maintenance

7.6.4 `MyISAM' Table Optimization
---------------------------------

To coalesce fragmented rows and eliminate wasted space that results
from deleting or updating rows, run *Note `myisamchk': myisamchk. in
recovery mode:

     shell> myisamchk -r TBL_NAME

You can optimize a table in the same way by using the *Note `OPTIMIZE
TABLE': optimize-table. SQL statement.  *Note `OPTIMIZE TABLE':
optimize-table. does a table repair and a key analysis, and also sorts
the index tree so that key lookups are faster. There is also no
possibility of unwanted interaction between a utility and the server,
because the server does all the work when you use *Note `OPTIMIZE
TABLE': optimize-table. See *Note optimize-table::.

*Note `myisamchk': myisamchk. has a number of other options that you
can use to improve the performance of a table:

   * `--analyze' or `-a': Perform key distribution analysis. This
     improves join performance by enabling the join optimizer to better
     choose the order in which to join the tables and which indexes it
     should use.

   * `--sort-index' or `-S': Sort the index blocks. This optimizes
     seeks and makes table scans that use indexes faster.

   * `--sort-records=INDEX_NUM' or `-R INDEX_NUM': Sort data rows
     according to a given index. This makes your data much more
     localized and may speed up range-based *Note `SELECT': select. and
     `ORDER BY' operations that use this index.

For a full description of all available options, see *Note myisamchk::.


File: manual.info,  Node: myisam-maintenance-schedule,  Prev: myisam-optimization,  Up: myisam-table-maintenance

7.6.5 Setting Up a `MyISAM' Table Maintenance Schedule
------------------------------------------------------

It is a good idea to perform table checks on a regular basis rather
than waiting for problems to occur. One way to check and repair
`MyISAM' tables is with the *Note `CHECK TABLE': check-table. and *Note
`REPAIR TABLE': repair-table. statements. See *Note
table-maintenance-sql::.

Another way to check tables is to use *Note `myisamchk': myisamchk. For
maintenance purposes, you can use *Note `myisamchk -s': myisamchk. The
`-s' option (short for `--silent') causes *Note `myisamchk': myisamchk.
to run in silent mode, printing messages only when errors occur.

It is also a good idea to enable automatic `MyISAM' table checking. For
example, whenever the machine has done a restart in the middle of an
update, you usually need to check each table that could have been
affected before it is used further. (These are `expected crashed
tables.') To cause the server to check `MyISAM' tables automatically,
start it with the `--myisam-recover' option. See *Note server-options::.

You should also check your tables regularly during normal system
operation. For example, you can run a `cron' job to check important
tables once a week, using a line like this in a `crontab' file:

     35 0 * * 0 /PATH/TO/MYISAMCHK --fast --silent /PATH/TO/DATADIR/*/*.MYI

This prints out information about crashed tables so that you can
examine and repair them as necessary.

To start with, execute *Note `myisamchk -s': myisamchk. each night on
all tables that have been updated during the last 24 hours. As you see
that problems occur infrequently, you can back off the checking
frequency to once a week or so.

Normally, MySQL tables need little maintenance. If you are performing
many updates to `MyISAM' tables with dynamic-sized rows (tables with
*Note `VARCHAR': char, *Note `BLOB': blob, or *Note `TEXT': blob.
columns) or have tables with many deleted rows you may want to
defragment/reclaim space from the tables from time to time. You can do
this by using *Note `OPTIMIZE TABLE': optimize-table. on the tables in
question. Alternatively, if you can stop the *Note `mysqld': mysqld.
server for a while, change location into the data directory and use
this command while the server is stopped:

     shell> myisamchk -r -s --sort-index --sort_buffer_size=16M */*.MYI


File: manual.info,  Node: optimization,  Next: language-structure,  Prev: backup-and-recovery,  Up: Top

8 Optimization
**************

* Menu:

* optimize-overview::            Optimization Overview
* execution-plan-information::   Obtaining Query Execution Plan Information
* statement-optimization::       Optimizing SQL Statements
* controlling-optimizer::        Controlling the Query Optimizer
* optimization-indexes::         Optimization and Indexes
* buffering-caching::            Buffering and Caching
* locking-issues::               Locking Issues
* optimizing-database-structure::  Optimizing Database Structure
* optimizing-the-server::        Optimizing the MySQL Server
* thread-information::           Examining Thread Information

This chapter explains different ways to optimize MySQL and provides
examples. Optimization is a complex task because ultimately it requires
understanding of the entire system to be optimized.  Although it may be
possible to perform some local optimizations with little knowledge of
your system or application, the more optimal you want your system to
become, the more you must know about it.


File: manual.info,  Node: optimize-overview,  Next: execution-plan-information,  Prev: optimization,  Up: optimization

8.1 Optimization Overview
=========================

* Menu:

* design-limitations::           MySQL Design Limitations and Tradeoffs
* portability::                  Designing Applications for Portability
* mysql-benchmarks::             The MySQL Benchmark Suite
* custom-benchmarks::            Using Your Own Benchmarks

The most important factor in making a system fast is its basic design.
You must also know what kinds of processing your system is doing, and
what its bottlenecks are. In most cases, system bottlenecks arise from
these sources:

   * Disk seeks. It takes time for the disk to find a piece of data.
     With modern disks, the mean time for this is usually lower than
     10ms, so we can in theory do about 100 seeks a second. This time
     improves slowly with new disks and is very hard to optimize for a
     single table. The way to optimize seek time is to distribute the
     data onto more than one disk.

   * Disk reading and writing. When the disk is at the correct
     position, we need to read the data. With modern disks, one disk
     delivers at least 10-20MB/s throughput. This is easier to optimize
     than seeks because you can read in parallel from multiple disks.

   * CPU cycles. When we have the data in main memory, we need to
     process it to get our result. Having small tables compared to the
     amount of memory is the most common limiting factor. But with
     small tables, speed is usually not the problem.

   * Memory bandwidth. When the CPU needs more data than can fit in the
     CPU cache, main memory bandwidth becomes a bottleneck.  This is an
     uncommon bottleneck for most systems, but one to be aware of.


File: manual.info,  Node: design-limitations,  Next: portability,  Prev: optimize-overview,  Up: optimize-overview

8.1.1 MySQL Design Limitations and Tradeoffs
--------------------------------------------

When using the `MyISAM' storage engine, MySQL uses extremely fast table
locking that permits multiple readers or a single writer. The biggest
problem with this storage engine occurs when you have a steady stream
of mixed updates and slow selects on a single table. If this is a
problem for certain tables, you can use another storage engine for
them. See *Note storage-engines::.

MySQL can work with both transactional and nontransactional tables. To
make it easier to work smoothly with nontransactional tables (which
cannot roll back if something goes wrong), MySQL has the following
rules. Note that these rules apply _only_ when not running in strict
SQL mode or if you use the `IGNORE' specifier for *Note `INSERT':
insert. or *Note `UPDATE': update.

   * All columns have default values.

   * If you insert an inappropriate or out-of-range value into a
     column, MySQL sets the column to the `best possible value' instead
     of reporting an error. For numeric values, this is 0, the smallest
     possible value or the largest possible value. For strings, this is
     either the empty string or as much of the string as can be stored
     in the column.

   * All calculated expressions return a value that can be used instead
     of signaling an error condition. For example, 1/0 returns `NULL'.

To change the preceding behaviors, you can enable stricter data
handling by setting the server SQL mode appropriately. For more
information about data handling, see *Note constraints::, *Note
server-sql-mode::, and *Note insert::.


File: manual.info,  Node: portability,  Next: mysql-benchmarks,  Prev: design-limitations,  Up: optimize-overview

8.1.2 Designing Applications for Portability
--------------------------------------------

Because all SQL servers implement different parts of standard SQL, it
takes work to write portable database applications. It is very easy to
achieve portability for very simple selects and inserts, but becomes
more difficult the more capabilities you require. If you want an
application that is fast with many database systems, it becomes even
more difficult.

All database systems have some weak points. That is, they have
different design compromises that lead to different behavior.

To make a complex application portable, you need to determine which SQL
servers it must work with, and then determine what features those
servers support. You can use the MySQL `crash-me' program to find
functions, types, and limits that you can use with a selection of
database servers. `crash-me' does not check for every possible feature,
but it is still reasonably comprehensive, performing about 450 tests.
An example of the type of information `crash-me' can provide is that you
should not use column names that are longer than 18 characters if you
want to be able to use Informix or DB2.

The `crash-me' program and the MySQL benchmarks are all very database
independent. By taking a look at how they are written, you can get a
feeling for what you must do to make your own applications database
independent. The programs can be found in the `sql-bench' directory of
MySQL source distributions. They are written in Perl and use the DBI
database interface. Use of DBI in itself solves part of the portability
problem because it provides database-independent access methods. See
*Note mysql-benchmarks::.

If you strive for database independence, you need to get a good feeling
for each SQL server's bottlenecks. For example, MySQL is very fast in
retrieving and updating rows for `MyISAM' tables, but has a problem in
mixing slow readers and writers on the same table. Transactional
database systems in general are not very good at generating summary
tables from log tables, because in this case row locking is almost
useless.

To make your application _really_ database independent, you should
define an easily extendable interface through which you manipulate your
data. For example, C++ is available on most systems, so it makes sense
to use a C++ class-based interface to the databases.

If you use some feature that is specific to a given database system
(such as the *Note `REPLACE': replace.  statement, which is specific to
MySQL), you should implement the same feature for other SQL servers by
coding an alternative method. Although the alternative might be slower,
it enables the other servers to perform the same tasks.

With MySQL, you can use the `/*! */' syntax to add MySQL-specific
keywords to a statement. The code inside `/* */' is treated as a
comment (and ignored) by most other SQL servers. For information about
writing comments, see *Note comments::.

If high performance is more important than exactness, as for some Web
applications, it is possible to create an application layer that caches
all results to give you even higher performance. By letting old results
expire after a while, you can keep the cache reasonably fresh. This
provides a method to handle high load spikes, in which case you can
dynamically increase the cache size and set the expiration timeout
higher until things get back to normal.

In this case, the table creation information should contain information
about the initial cache size and how often the table should normally be
refreshed.

An attractive alternative to implementing an application cache is to
use the MySQL query cache. By enabling the query cache, the server
handles the details of determining whether a query result can be
reused. This simplifies your application. See *Note query-cache::.


File: manual.info,  Node: mysql-benchmarks,  Next: custom-benchmarks,  Prev: portability,  Up: optimize-overview

8.1.3 The MySQL Benchmark Suite
-------------------------------

This benchmark suite is meant to tell any user what operations a given
SQL implementation performs well or poorly. You can get a good idea for
how the benchmarks work by looking at the code and results in the
`sql-bench' directory in any MySQL source distribution.

Note that this benchmark is single-threaded, so it measures the minimum
time for the operations performed. We plan to add multi-threaded tests
to the benchmark suite in the future.

To use the benchmark suite, the following requirements must be
satisfied:

   * The benchmark suite is provided with MySQL source distributions.
     You can either download a released distribution from
     `http://dev.mysql.com/downloads/', or use the current development
     source tree. (See *Note installing-development-tree::.)

   * The benchmark scripts are written in Perl and use the Perl DBI
     module to access database servers, so DBI must be installed. You
     also need the server-specific DBD drivers for each of the servers
     you want to test. For example, to test MySQL, PostgreSQL, and DB2,
     you must have the `DBD::mysql', `DBD::Pg', and `DBD::DB2' modules
     installed. See *Note perl-support::.

After you obtain a MySQL source distribution, you can find the
benchmark suite located in its `sql-bench' directory. To run the
benchmark tests, build MySQL, and then change location into the
`sql-bench' directory and execute the `run-all-tests' script:

     shell> cd sql-bench
     shell> perl run-all-tests --server=SERVER_NAME

SERVER_NAME should be the name of one of the supported servers. To get
a list of all options and supported servers, invoke this command:

     shell> perl run-all-tests --help

The `crash-me' script also is located in the `sql-bench' directory.
`crash-me' tries to determine what features a database system supports
and what its capabilities and limitations are by actually running
queries. For example, it determines:

   * What data types are supported

   * How many indexes are supported

   * What functions are supported

   * How big a query can be

   * How big a *Note `VARCHAR': char. column can be

For more information about benchmark results, visit
http://www.mysql.com/why-mysql/benchmarks/.


File: manual.info,  Node: custom-benchmarks,  Prev: mysql-benchmarks,  Up: optimize-overview

8.1.4 Using Your Own Benchmarks
-------------------------------

You should definitely benchmark your application and database to find
out where the bottlenecks are. After fixing one bottleneck (or by
replacing it with a `dummy' module), you can proceed to identify the
next bottleneck. Even if the overall performance for your application
currently is acceptable, you should at least make a plan for each
bottleneck and decide how to solve it if someday you really need the
extra performance.

For examples of portable benchmark programs, look at those in the MySQL
benchmark suite. See *Note mysql-benchmarks::. You can take any program
from this suite and modify it for your own needs. By doing this, you
can try different solutions to your problem and test which really is
fastest for you.

Another free benchmark suite is the Open Source Database Benchmark,
available at `http://osdb.sourceforge.net/'.

It is very common for a problem to occur only when the system is very
heavily loaded. We have had many customers who contact us when they
have a (tested) system in production and have encountered load
problems. In most cases, performance problems turn out to be due to
issues of basic database design (for example, table scans are not good
under high load) or problems with the operating system or libraries.
Most of the time, these problems would be much easier to fix if the
systems were not already in production.

To avoid problems like this, you should put some effort into
benchmarking your whole application under the worst possible load. For
example, you can try benchmarking packages such as SysBench and DBT2,
available at `http://sourceforge.net/projects/sysbench/', and
`http://osdldbt.sourceforge.net/#dbt2'. These packages can bring a
system to its knees, so be sure to use them only on your development
systems.


File: manual.info,  Node: execution-plan-information,  Next: statement-optimization,  Prev: optimize-overview,  Up: optimization

8.2 Obtaining Query Execution Plan Information
==============================================

* Menu:

* using-explain::                Optimizing Queries with `EXPLAIN'
* explain-output::               `EXPLAIN' Output Format
* estimating-performance::       Estimating Query Performance


File: manual.info,  Node: using-explain,  Next: explain-output,  Prev: execution-plan-information,  Up: execution-plan-information

8.2.1 Optimizing Queries with `EXPLAIN'
---------------------------------------

The *Note `EXPLAIN': explain. statement can be used either as a way to
obtain information about how MySQL executes a statement, or as a
synonym for *Note `DESCRIBE': describe.:

   * When you precede a *Note `SELECT': select.  statement with the
     keyword *Note `EXPLAIN': explain, MySQL displays information from
     the optimizer about the query execution plan. That is, MySQL
     explains how it would process the statement, including information
     about how tables are joined and in which order.  *Note `EXPLAIN
     EXTENDED': explain. can be used to provide additional information.

     The following sections describe how to use *Note `EXPLAIN':
     explain. and *Note `EXPLAIN EXTENDED': explain. to obtain query
     execution plan information.

   * *Note `EXPLAIN TBL_NAME': explain. is synonymous with `DESCRIBE
     TBL_NAME' or `SHOW COLUMNS FROM TBL_NAME'. For information about
     *Note `DESCRIBE': describe.  and *Note `SHOW COLUMNS':
     show-columns, see *Note describe::, and *Note show-columns::.

With the help of *Note `EXPLAIN': explain, you can see where you should
add indexes to tables so that the statement executes faster by using
indexes to find rows. You can also use *Note `EXPLAIN': explain. to
check whether the optimizer joins the tables in an optimal order. To
give a hint to the optimizer to use a join order corresponding to the
order in which the tables are named in a *Note `SELECT': select.
statement, begin the statement with `SELECT STRAIGHT_JOIN' rather than
just *Note `SELECT': select. (See *Note select::.)

If you have a problem with indexes not being used when you believe that
they should be, run *Note `ANALYZE TABLE': analyze-table. to update
table statistics, such as cardinality of keys, that can affect the
choices the optimizer makes. See *Note analyze-table::.


File: manual.info,  Node: explain-output,  Next: estimating-performance,  Prev: using-explain,  Up: execution-plan-information

8.2.2 `EXPLAIN' Output Format
-----------------------------

The *Note `EXPLAIN': explain. statement provides information about the
execution plan for a *Note `SELECT': select. statement.

*Note `EXPLAIN': explain. returns a row of information for each table
used in the *Note `SELECT': select. statement. It lists the tables in
the output in the order that MySQL would read them while processing the
statement. MySQL resolves all joins using a nested-loop join method.
This means that MySQL reads a row from the first table, and then finds
a matching row in the second table, the third table, and so on. When
all tables are processed, MySQL outputs the selected columns and
backtracks through the table list until a table is found for which there
are more matching rows. The next row is read from this table and the
process continues with the next table.

When the `EXTENDED' keyword is used, *Note `EXPLAIN': explain. produces
extra information that can be viewed by issuing a *Note `SHOW
WARNINGS': show-warnings. statement following the *Note `EXPLAIN':
explain. statement. This information displays how the optimizer
qualifies table and column names in the *Note `SELECT': select.
statement, what the *Note `SELECT': select. looks like after the
application of rewriting and optimization rules, and possibly other
notes about the optimization process.

   * `EXPLAIN' Output Columns

   * `EXPLAIN' Join Types

   * `EXPLAIN' Extra Information

   * `EXPLAIN' Output Interpretation

* `EXPLAIN' Output Columns *

This section describes the output columns produced by *Note `EXPLAIN':
explain. Later sections provide additional information about the `type'
and `Extra' columns.

Each output row from *Note `EXPLAIN': explain.  provides information
about one table. Each row contains the values summarized in *Note
explain-output-column-table::, and described in more detail following
the table.

*`EXPLAIN' Output Columns*

Column             Meaning
`id'               The `SELECT' identifier
`select_type'      The `SELECT' type
`table'            The table for the output row
`type'             The join type
`possible_keys'    The possible indexes to choose
`key'              The index actually chosen
`key_len'          The length of the chosen key
`ref'              The columns compared to the index
`rows'             Estimate of rows to be examined
`Extra'            Additional information

   *  `id'

     The *Note `SELECT': select. identifier. This is the sequential
     number of the *Note `SELECT': select. within the query.

   *  `select_type'

     The type of *Note `SELECT': select, which can be any of those
     shown in the following table.

     `select_type'     Meaning
     Value             
     `SIMPLE'          Simple *Note `SELECT': select. (not using *Note
                       `UNION': union. or subqueries)
     `PRIMARY'         Outermost *Note `SELECT': select.
     *Note `UNION':    Second or later *Note `SELECT': select. statement
     union.            in a *Note `UNION': union.
     `DEPENDENT UNION' Second or later *Note `SELECT': select. statement
                       in a *Note `UNION': union, dependent on outer
                       query
     `UNION RESULT'    Result of a *Note `UNION': union.
     `SUBQUERY'        First *Note `SELECT': select. in subquery
     `DEPENDENT        First *Note `SELECT': select. in subquery,
     SUBQUERY'         dependent on outer query
     `DERIVED'         Derived table *Note `SELECT': select. (subquery in
                       `FROM' clause)
     `UNCACHEABLE      A subquery for which the result cannot be cached
     SUBQUERY'         and must be re-evaluated for each row of the
                       outer query

     `DEPENDENT' typically signifies the use of a correlated subquery.
     See *Note correlated-subqueries::.

     `DEPENDENT SUBQUERY' evaluation differs from `UNCACHEABLE
     SUBQUERY' evaluation. For `DEPENDENT SUBQUERY', the subquery is
     re-evaluated only once for each set of different values of the
     variables from its outer context. For `UNCACHEABLE SUBQUERY', the
     subquery is re-evaluated for each row of the outer context.
     Cacheability of subqueries is subject to the restrictions detailed
     in *Note query-cache-operation::. For example, referring to user
     variables makes a subquery uncacheable.

   *  `table'

     The table to which the row of output refers.

   *  `type'

     The join type. For descriptions of the different types, see
     `EXPLAIN' Join Types.

   *  `possible_keys'

     The `possible_keys' column indicates which indexes MySQL can
     choose from use to find the rows in this table. Note that this
     column is totally independent of the order of the tables as
     displayed in the output from *Note `EXPLAIN': explain. That means
     that some of the keys in `possible_keys' might not be usable in
     practice with the generated table order.

     If this column is `NULL', there are no relevant indexes. In this
     case, you may be able to improve the performance of your query by
     examining the `WHERE' clause to check whether it refers to some
     column or columns that would be suitable for indexing. If so,
     create an appropriate index and check the query with *Note
     `EXPLAIN': explain. again. See *Note alter-table::.

     To see what indexes a table has, use `SHOW INDEX FROM TBL_NAME'.

   *  `key'

     The `key' column indicates the key (index) that MySQL actually
     decided to use. If MySQL decides to use one of the `possible_keys'
     indexes to look up rows, that index is listed as the key value.

     It is possible that `key' will name an index that is not present
     in the `possible_keys' value. This can happen if none of the
     `possible_keys' indexes are suitable for looking up rows, but all
     the columns selected by the query are columns of some other index.
     That is, the named index covers the selected columns, so although
     it is not used to determine which rows to retrieve, an index scan
     is more efficient than a data row scan.

     For `InnoDB', a secondary index might cover the selected columns
     even if the query also selects the primary key because `InnoDB'
     stores the primary key value with each secondary index. If `key'
     is `NULL', MySQL found no index to use for executing the query more
     efficiently.

     To force MySQL to use or ignore an index listed in the
     `possible_keys' column, use `FORCE INDEX', `USE INDEX', or `IGNORE
     INDEX' in your query. See *Note index-hints::.

     For `MyISAM' and `BDB' tables, running *Note `ANALYZE TABLE':
     analyze-table.  helps the optimizer choose better indexes. For
     `MyISAM' tables, *Note `myisamchk --analyze': myisamchk. does the
     same. See *Note analyze-table::, and *Note
     myisam-table-maintenance::.

   *  `key_len'

     The `key_len' column indicates the length of the key that MySQL
     decided to use. The length is `NULL' if the `key' column says
     `NULL'. Note that the value of `key_len' enables you to determine
     how many parts of a multiple-part key MySQL actually uses.

   *  `ref'

     The `ref' column shows which columns or constants are compared to
     the index named in the `key' column to select rows from the table.

   *  `rows'

     The `rows' column indicates the number of rows MySQL believes it
     must examine to execute the query.

     For *Note `InnoDB': innodb-storage-engine. tables, this number is
     an estimate, and may not always be exact.

   *  `Extra'

     This column contains additional information about how MySQL
     resolves the query. For descriptions of the different values, see
     `EXPLAIN' Extra Information.

* `EXPLAIN' Join Types *

The `type' column of *Note `EXPLAIN': explain. output describes how
tables are joined. The following list describes the join types, ordered
from the best type to the worst:

   *  `system'

     The table has only one row (= system table). This is a special
     case of the `const' join type.

   *  `const'

     The table has at most one matching row, which is read at the start
     of the query. Because there is only one row, values from the
     column in this row can be regarded as constants by the rest of the
     optimizer.  `const' tables are very fast because they are read
     only once.

     `const' is used when you compare all parts of a `PRIMARY KEY' or
     `UNIQUE' index to constant values. In the following queries,
     TBL_NAME can be used as a `const' table:

          SELECT * FROM TBL_NAME WHERE PRIMARY_KEY=1;

          SELECT * FROM TBL_NAME
            WHERE PRIMARY_KEY_PART1=1 AND PRIMARY_KEY_PART2=2;

   *  `eq_ref'

     One row is read from this table for each combination of rows from
     the previous tables. Other than the `system' and `const' types,
     this is the best possible join type. It is used when all parts of
     an index are used by the join and the index is a `PRIMARY KEY' or
     `UNIQUE NOT NULL' index.

     `eq_ref' can be used for indexed columns that are compared using
     the `=' operator. The comparison value can be a constant or an
     expression that uses columns from tables that are read before this
     table. In the following examples, MySQL can use an `eq_ref' join to
     process REF_TABLE:

          SELECT * FROM REF_TABLE,OTHER_TABLE
            WHERE REF_TABLE.KEY_COLUMN=OTHER_TABLE.COLUMN;

          SELECT * FROM REF_TABLE,OTHER_TABLE
            WHERE REF_TABLE.KEY_COLUMN_PART1=OTHER_TABLE.COLUMN
            AND REF_TABLE.KEY_COLUMN_PART2=1;

   *  `ref'

     All rows with matching index values are read from this table for
     each combination of rows from the previous tables.  `ref' is used
     if the join uses only a leftmost prefix of the key or if the key
     is not a `PRIMARY KEY' or `UNIQUE' index (in other words, if the
     join cannot select a single row based on the key value). If the
     key that is used matches only a few rows, this is a good join type.

     `ref' can be used for indexed columns that are compared using the
     `=' or `<=>' operator. In the following examples, MySQL can use a
     `ref' join to process REF_TABLE:

          SELECT * FROM REF_TABLE WHERE KEY_COLUMN=EXPR;

          SELECT * FROM REF_TABLE,OTHER_TABLE
            WHERE REF_TABLE.KEY_COLUMN=OTHER_TABLE.COLUMN;

          SELECT * FROM REF_TABLE,OTHER_TABLE
            WHERE REF_TABLE.KEY_COLUMN_PART1=OTHER_TABLE.COLUMN
            AND REF_TABLE.KEY_COLUMN_PART2=1;

   *  `fulltext'

     The join is performed using a `FULLTEXT' index.

   *  `ref_or_null'

     This join type is like `ref', but with the addition that MySQL
     does an extra search for rows that contain `NULL' values. This
     join type optimization is used most often in resolving subqueries.
     In the following examples, MySQL can use a `ref_or_null' join to
     process REF_TABLE:

          SELECT * FROM REF_TABLE
            WHERE KEY_COLUMN=EXPR OR KEY_COLUMN IS NULL;

     See *Note is-null-optimization::.

   *  `index_merge'

     This join type indicates that the Index Merge optimization is
     used. In this case, the `key' column in the output row contains a
     list of indexes used, and `key_len' contains a list of the longest
     key parts for the indexes used. For more information, see *Note
     index-merge-optimization::.

   *  `unique_subquery'

     This type replaces `ref' for some `IN' subqueries of the following
     form:

          VALUE IN (SELECT PRIMARY_KEY FROM SINGLE_TABLE WHERE SOME_EXPR)

     `unique_subquery' is just an index lookup function that replaces
     the subquery completely for better efficiency.

   *  `index_subquery'

     This join type is similar to `unique_subquery'. It replaces `IN'
     subqueries, but it works for nonunique indexes in subqueries of
     the following form:

          VALUE IN (SELECT KEY_COLUMN FROM SINGLE_TABLE WHERE SOME_EXPR)

   *  `range'

     Only rows that are in a given range are retrieved, using an index
     to select the rows. The `key' column in the output row indicates
     which index is used. The `key_len' contains the longest key part
     that was used. The `ref' column is `NULL' for this type.

     `range' can be used when a key column is compared to a constant
     using any of the `=', `<>', `>', `>=', `<', `<=', `IS NULL', `<=>',
     `BETWEEN', or `IN()' operators:

          SELECT * FROM TBL_NAME
            WHERE KEY_COLUMN = 10;

          SELECT * FROM TBL_NAME
            WHERE KEY_COLUMN BETWEEN 10 and 20;

          SELECT * FROM TBL_NAME
            WHERE KEY_COLUMN IN (10,20,30);

          SELECT * FROM TBL_NAME
            WHERE KEY_PART1= 10 AND KEY_PART2 IN (10,20,30);

   *  `index'

     This join type is the same as `ALL', except that only the index
     tree is scanned. This usually is faster than `ALL' because the
     index file usually is smaller than the data file.

     MySQL can use this join type when the query uses only columns that
     are part of a single index.

   *  `ALL'

     A full table scan is done for each combination of rows from the
     previous tables. This is normally not good if the table is the
     first table not marked `const', and usually _very_ bad in all
     other cases. Normally, you can avoid `ALL' by adding indexes that
     enable row retrieval from the table based on constant values or
     column values from earlier tables.

* `EXPLAIN' Extra Information *

The `Extra' column of *Note `EXPLAIN': explain. output contains
additional information about how MySQL resolves the query. The
following list explains the values that can appear in this column. If
you want to make your queries as fast as possible, look out for `Extra'
values of `Using filesort' and `Using temporary'.

   * `const row not found'

     For a query such as `SELECT ... FROM TBL_NAME', the table was
     empty.

   * `Distinct'

     MySQL is looking for distinct values, so it stops searching for
     more rows for the current row combination after it has found the
     first matching row.

   * `Full scan on NULL key'

     This occurs for subquery optimization as a fallback strategy when
     the optimizer cannot use an index-lookup access method.

   * `Impossible HAVING'

     The `HAVING' clause is always false and cannot select any rows.

   * `Impossible WHERE'

     The `WHERE' clause is always false and cannot select any rows.

   * `Impossible WHERE noticed after reading const tables'

     MySQL has read all `const' (and `system') tables and notice that
     the `WHERE' clause is always false.

   * `No matching min/max row'

     No row satisfies the condition for a query such as `SELECT
     MIN(...) FROM ... WHERE CONDITION'.

   * `no matching row in const table'

     For a query with a join, there was an empty table or a table with
     no rows satisfying a unique index condition.

   * `No tables used'

     The query has no `FROM' clause, or has a `FROM DUAL' clause.

   * `Not exists'

     MySQL was able to do a `LEFT JOIN' optimization on the query and
     does not examine more rows in this table for the previous row
     combination after it finds one row that matches the `LEFT JOIN'
     criteria. Here is an example of the type of query that can be
     optimized this way:

          SELECT * FROM t1 LEFT JOIN t2 ON t1.id=t2.id
            WHERE t2.id IS NULL;

     Assume that `t2.id' is defined as `NOT NULL'. In this case, MySQL
     scans `t1' and looks up the rows in `t2' using the values of
     `t1.id'. If MySQL finds a matching row in `t2', it knows that
     `t2.id' can never be `NULL', and does not scan through the rest of
     the rows in `t2' that have the same `id' value. In other words,
     for each row in `t1', MySQL needs to do only a single lookup in
     `t2', regardless of how many rows actually match in `t2'.

   * `Range checked for each record (index map: N)'

     MySQL found no good index to use, but found that some of indexes
     might be used after column values from preceding tables are known.
     For each row combination in the preceding tables, MySQL checks
     whether it is possible to use a `range' or `index_merge' access
     method to retrieve rows. This is not very fast, but is faster than
     performing a join with no index at all. The applicability criteria
     are as described in *Note range-optimization::, and *Note
     index-merge-optimization::, with the exception that all column
     values for the preceding table are known and considered to be
     constants.

     Indexes are numbered beginning with 1, in the same order as shown
     by *Note `SHOW INDEX': show-index. for the table. The index map
     value N is a bitmask value that indicates which indexes are
     candidates.  For example, a value of `0x19' (binary 11001) means
     that indexes 1, 4, and 5 will be considered.

   * `Select tables optimized away'

     The query contained only aggregate functions (`MIN()', `MAX()')
     that were all resolved using an index, or `COUNT(*)' for `MyISAM',
     and no `GROUP BY' clause. The optimizer determined that only one
     row should be returned.

   * `unique row not found'

     For a query such as `SELECT ... FROM TBL_NAME', no rows satisfy
     the condition for a `UNIQUE' index or `PRIMARY KEY' on the table.

   * `Using filesort'

     MySQL must do an extra pass to find out how to retrieve the rows
     in sorted order. The sort is done by going through all rows
     according to the join type and storing the sort key and pointer to
     the row for all rows that match the `WHERE' clause. The keys then
     are sorted and the rows are retrieved in sorted order. See *Note
     order-by-optimization::.

   * `Using index'

     The column information is retrieved from the table using only
     information in the index tree without having to do an additional
     seek to read the actual row. This strategy can be used when the
     query uses only columns that are part of a single index.

     If the `Extra' column also says `Using where', it means the index
     is being used to perform lookups of key values. Without `Using
     where', the optimizer may be reading the index to avoid reading
     data rows but not using it for lookups. For example, if the index
     is a covering index for the query, the optimizer may scan it
     without using it for lookups.

   * `Using index for group-by'

     Similar to the `Using index' table access method, `Using index for
     group-by' indicates that MySQL found an index that can be used to
     retrieve all columns of a `GROUP BY' or `DISTINCT' query without
     any extra disk access to the actual table. Additionally, the index
     is used in the most efficient way so that for each group, only a
     few index entries are read. For details, see *Note
     group-by-optimization::.

   * `Using sort_union(...)', `Using union(...)', `Using intersect(...)'

     These indicate how index scans are merged for the `index_merge'
     join type.  See *Note index-merge-optimization::.

   * `Using temporary'

     To resolve the query, MySQL needs to create a temporary table to
     hold the result. This typically happens if the query contains
     `GROUP BY' and `ORDER BY' clauses that list columns differently.

   * `Using where'

     A `WHERE' clause is used to restrict which rows to match against
     the next table or send to the client.  Unless you specifically
     intend to fetch or examine all rows from the table, you may have
     something wrong in your query if the `Extra' value is not `Using
     where' and the table join type is `ALL' or `index'. Even if you are
     using an index for all parts of a `WHERE' clause, you may see
     `Using where' if the column can be `NULL'.

   * `Using where with pushed condition'

     This item applies to *Note `NDBCLUSTER': mysql-cluster.  tables
     _only_. It means that MySQL Cluster is using the Condition
     Pushdown optimization to improve the efficiency of a direct
     comparison between a nonindexed column and a constant. In such
     cases, the condition is `pushed down' to the cluster's data nodes
     and is evaluated on all data nodes simultaneously. This eliminates
     the need to send nonmatching rows over the network, and can speed
     up such queries by a factor of 5 to 10 times over cases where
     Condition Pushdown could be but is not used. For more information,
     see *Note condition-pushdown-optimization::.

* `EXPLAIN' Output Interpretation *

You can get a good indication of how good a join is by taking the
product of the values in the `rows' column of the *Note `EXPLAIN':
explain. output. This should tell you roughly how many rows MySQL must
examine to execute the query. If you restrict queries with the
`max_join_size' system variable, this row product also is used to
determine which multiple-table *Note `SELECT': select. statements to
execute and which to abort. See *Note server-parameters::.

The following example shows how a multiple-table join can be optimized
progressively based on the information provided by *Note `EXPLAIN':
explain.

Suppose that you have the *Note `SELECT': select.  statement shown here
and that you plan to examine it using *Note `EXPLAIN': explain.:

     EXPLAIN SELECT tt.TicketNumber, tt.TimeIn,
                    tt.ProjectReference, tt.EstimatedShipDate,
                    tt.ActualShipDate, tt.ClientID,
                    tt.ServiceCodes, tt.RepetitiveID,
                    tt.CurrentProcess, tt.CurrentDPPerson,
                    tt.RecordVolume, tt.DPPrinted, et.COUNTRY,
                    et_1.COUNTRY, do.CUSTNAME
             FROM tt, et, et AS et_1, do
             WHERE tt.SubmitTime IS NULL
               AND tt.ActualPC = et.EMPLOYID
               AND tt.AssignedPC = et_1.EMPLOYID
               AND tt.ClientID = do.CUSTNMBR;

For this example, make the following assumptions:

   * The columns being compared have been declared as follows.

     Table   Column            Data Type
     `tt'    `ActualPC'        `CHAR(10)'
     `tt'    `AssignedPC'      `CHAR(10)'
     `tt'    `ClientID'        `CHAR(10)'
     `et'    `EMPLOYID'        `CHAR(15)'
     `do'    `CUSTNMBR'        `CHAR(15)'

   * The tables have the following indexes.

     Table   Index
     `tt'    `ActualPC'
     `tt'    `AssignedPC'
     `tt'    `ClientID'
     `et'    `EMPLOYID' (primary key)
     `do'    `CUSTNMBR' (primary key)

   * The `tt.ActualPC' values are not evenly distributed.

Initially, before any optimizations have been performed, the *Note
`EXPLAIN': explain. statement produces the following information:

     table type possible_keys key  key_len ref  rows  Extra
     et    ALL  PRIMARY       NULL NULL    NULL 74
     do    ALL  PRIMARY       NULL NULL    NULL 2135
     et_1  ALL  PRIMARY       NULL NULL    NULL 74
     tt    ALL  AssignedPC,   NULL NULL    NULL 3872
                ClientID,
                ActualPC
           Range checked for each record (index map: 0x23)

Because `type' is `ALL' for each table, this output indicates that
MySQL is generating a Cartesian product of all the tables; that is,
every combination of rows. This takes quite a long time, because the
product of the number of rows in each table must be examined. For the
case at hand, this product is 74 x 2135 x 74 x 3872 = 45,268,558,720
rows. If the tables were bigger, you can only imagine how long it would
take.

One problem here is that MySQL can use indexes on columns more
efficiently if they are declared as the same type and size. In this
context, *Note `VARCHAR': char. and *Note `CHAR': char. are considered
the same if they are declared as the same size.  `tt.ActualPC' is
declared as `CHAR(10)' and `et.EMPLOYID' is `CHAR(15)', so there is a
length mismatch.

To fix this disparity between column lengths, use *Note `ALTER TABLE':
alter-table. to lengthen `ActualPC' from 10 characters to 15 characters:

     mysql> ALTER TABLE tt MODIFY ActualPC VARCHAR(15);

Now `tt.ActualPC' and `et.EMPLOYID' are both `VARCHAR(15)'. Executing
the *Note `EXPLAIN': explain. statement again produces this result:

     table type   possible_keys key     key_len ref         rows    Extra
     tt    ALL    AssignedPC,   NULL    NULL    NULL        3872    Using
                  ClientID,                                         where
                  ActualPC
     do    ALL    PRIMARY       NULL    NULL    NULL        2135
           Range checked for each record (index map: 0x1)
     et_1  ALL    PRIMARY       NULL    NULL    NULL        74
           Range checked for each record (index map: 0x1)
     et    eq_ref PRIMARY       PRIMARY 15      tt.ActualPC 1

This is not perfect, but is much better: The product of the `rows'
values is less by a factor of 74. This version executes in a couple of
seconds.

A second alteration can be made to eliminate the column length
mismatches for the `tt.AssignedPC = et_1.EMPLOYID' and `tt.ClientID =
do.CUSTNMBR' comparisons:

     mysql> ALTER TABLE tt MODIFY AssignedPC VARCHAR(15),
         ->                MODIFY ClientID   VARCHAR(15);

After that modification, *Note `EXPLAIN': explain.  produces the output
shown here:

     table type   possible_keys key      key_len ref           rows Extra
     et    ALL    PRIMARY       NULL     NULL    NULL          74
     tt    ref    AssignedPC,   ActualPC 15      et.EMPLOYID   52   Using
                  ClientID,                                         where
                  ActualPC
     et_1  eq_ref PRIMARY       PRIMARY  15      tt.AssignedPC 1
     do    eq_ref PRIMARY       PRIMARY  15      tt.ClientID   1

At this point, the query is optimized almost as well as possible. The
remaining problem is that, by default, MySQL assumes that values in the
`tt.ActualPC' column are evenly distributed, and that is not the case
for the `tt' table. Fortunately, it is easy to tell MySQL to analyze
the key distribution:

     mysql> ANALYZE TABLE tt;

With the additional index information, the join is perfect and *Note
`EXPLAIN': explain. produces this result:

     table type   possible_keys key     key_len ref           rows Extra
     tt    ALL    AssignedPC    NULL    NULL    NULL          3872 Using
                  ClientID,                                        where
                  ActualPC
     et    eq_ref PRIMARY       PRIMARY 15      tt.ActualPC   1
     et_1  eq_ref PRIMARY       PRIMARY 15      tt.AssignedPC 1
     do    eq_ref PRIMARY       PRIMARY 15      tt.ClientID   1

Note that the `rows' column in the output from *Note `EXPLAIN':
explain. is an educated guess from the MySQL join optimizer. You should
check whether the numbers are even close to the truth by comparing the
`rows' product with the actual number of rows that the query returns.
If the numbers are quite different, you might get better performance by
using `STRAIGHT_JOIN' in your *Note `SELECT': select. statement and
trying to list the tables in a different order in the `FROM' clause.

It is possible in some cases to execute statements that modify data
when *Note `EXPLAIN SELECT': explain. is used with a subquery; for more
information, see *Note from-clause-subqueries::.


File: manual.info,  Node: estimating-performance,  Prev: explain-output,  Up: execution-plan-information

8.2.3 Estimating Query Performance
----------------------------------

In most cases, you can estimate query performance by counting disk
seeks. For small tables, you can usually find a row in one disk seek
(because the index is probably cached). For bigger tables, you can
estimate that, using B-tree indexes, you need this many seeks to find a
row: `log(ROW_COUNT) / log(INDEX_BLOCK_LENGTH / 3 * 2 / (INDEX_LENGTH +
DATA_POINTER_LENGTH)) + 1'.

In MySQL, an index block is usually 1,024 bytes and the data pointer is
usually four bytes. For a 500,000-row table with a key value length of
three bytes (the size of *Note `MEDIUMINT': numeric-types.), the
formula indicates `log(500,000)/log(1024/3*2/(3+4)) + 1' = `4' seeks.

This index would require storage of about 500,000 * 7 * 3/2 = 5.2MB
(assuming a typical index buffer fill ratio of 2/3), so you probably
have much of the index in memory and so need only one or two calls to
read data to find the row.

For writes, however, you need four seek requests to find where to place
a new index value and normally two seeks to update the index and write
the row.

Note that the preceding discussion does not mean that your application
performance slowly degenerates by log N. As long as everything is
cached by the OS or the MySQL server, things become only marginally
slower as the table gets bigger. After the data gets too big to be
cached, things start to go much slower until your applications are
bound only by disk seeks (which increase by log N). To avoid this,
increase the key cache size as the data grows. For `MyISAM' tables, the
key cache size is controlled by the `key_buffer_size' system variable.
See *Note server-parameters::.


File: manual.info,  Node: statement-optimization,  Next: controlling-optimizer,  Prev: execution-plan-information,  Up: optimization

8.3 Optimizing SQL Statements
=============================

* Menu:

* select-optimization::          Optimizing `SELECT' Statements
* non-select-optimization::      Optimizing Non-`SELECT' Statements
* miscellaneous-optimization-tips::  Other Optimization Tips


File: manual.info,  Node: select-optimization,  Next: non-select-optimization,  Prev: statement-optimization,  Up: statement-optimization

8.3.1 Optimizing `SELECT' Statements
------------------------------------

* Menu:

* select-speed::                 Speed of `SELECT' Statements
* where-optimizations::          `WHERE' Clause Optimization
* range-optimization::           Range Optimization
* index-merge-optimization::     Index Merge Optimization
* condition-pushdown-optimization::  Engine Condition Pushdown Optimization
* is-null-optimization::         `IS NULL' Optimization
* left-join-optimization::       `LEFT JOIN' and `RIGHT JOIN' Optimization
* nested-loop-joins::            Nested-Loop Join Algorithms
* nested-join-optimization::     Nested Join Optimization
* outer-join-simplification::    Outer Join Simplification
* order-by-optimization::        `ORDER BY' Optimization
* group-by-optimization::        `GROUP BY' Optimization
* distinct-optimization::        `DISTINCT' Optimization
* in-subquery-optimization::     Optimizing `IN'/`=ANY' Subqueries
* limit-optimization::           `LIMIT' Optimization
* how-to-avoid-table-scan::      How to Avoid Table Scans

First, one factor affects all statements: The more complex your
permissions setup, the more overhead you have. Using simpler
permissions when you issue *Note `GRANT': grant.  statements enables
MySQL to reduce permission-checking overhead when clients execute
statements. For example, if you do not grant any table-level or
column-level privileges, the server need not ever check the contents of
the `tables_priv' and `columns_priv' tables. Similarly, if you place no
resource limits on any accounts, the server does not have to perform
resource counting. If you have a very high statement-processing load,
it may be worth the time to use a simplified grant structure to reduce
permission-checking overhead.

If your problem is with a specific MySQL expression or function, you
can perform a timing test by invoking the `BENCHMARK()' function using
the *Note `mysql': mysql. client program. Its syntax is
`BENCHMARK(LOOP_COUNT,EXPRESSION)'.  The return value is always zero,
but *Note `mysql': mysql.  prints a line displaying approximately how
long the statement took to execute. For example:

     mysql> SELECT BENCHMARK(1000000,1+1);
     +------------------------+
     | BENCHMARK(1000000,1+1) |
     +------------------------+
     |                      0 |
     +------------------------+
     1 row in set (0.32 sec)

This result was obtained on a Pentium II 400MHz system. It shows that
MySQL can execute 1,000,000 simple addition expressions in 0.32 seconds
on that system.

All MySQL functions should be highly optimized, but there may be some
exceptions. `BENCHMARK()' is an excellent tool for finding out if some
function is a problem for your queries.


File: manual.info,  Node: select-speed,  Next: where-optimizations,  Prev: select-optimization,  Up: select-optimization

8.3.1.1 Speed of `SELECT' Statements
....................................

In general, when you want to make a slow `SELECT ...  WHERE' query
faster, the first thing to check is whether you can add an index. All
references between different tables should usually be done with
indexes. You can use the *Note `EXPLAIN': explain. statement to
determine which indexes are used for a *Note `SELECT': select. See
*Note using-explain::, and *Note mysql-indexes::.

Some general tips for speeding up queries on `MyISAM' tables:

   * To help MySQL better optimize queries, use *Note `ANALYZE TABLE':
     analyze-table. or run *Note `myisamchk --analyze': myisamchk. on a
     table after it has been loaded with data. This updates a value for
     each index part that indicates the average number of rows that
     have the same value. (For unique indexes, this is always 1.) MySQL
     uses this to decide which index to choose when you join two tables
     based on a nonconstant expression. You can check the result from
     the table analysis by using `SHOW INDEX FROM TBL_NAME' and
     examining the `Cardinality' value.  *Note `myisamchk --description
     --verbose': myisamchk. shows index distribution information.

   * To sort an index and data according to an index, use *Note
     `myisamchk --sort-index --sort-records=1': myisamchk.  (assuming
     that you want to sort on index 1). This is a good way to make
     queries faster if you have a unique index from which you want to
     read all rows in order according to the index. The first time you
     sort a large table this way, it may take a long time.


File: manual.info,  Node: where-optimizations,  Next: range-optimization,  Prev: select-speed,  Up: select-optimization

8.3.1.2 `WHERE' Clause Optimization
...................................

This section discusses optimizations that can be made for processing
`WHERE' clauses. The examples use *Note `SELECT': select. statements,
but the same optimizations apply for `WHERE' clauses in *Note `DELETE':
delete. and *Note `UPDATE': update. statements.

Work on the MySQL optimizer is ongoing, so this section is incomplete.
MySQL performs a great many optimizations, not all of which are
documented here.

Some of the optimizations performed by MySQL follow:

   * Removal of unnecessary parentheses:

             ((a AND b) AND c OR (((a AND b) AND (c AND d))))
          -> (a AND b AND c) OR (a AND b AND c AND d)

   * Constant folding:

             (a<b AND b=c) AND a=5
          -> b>5 AND b=c AND a=5

   * Constant condition removal (needed because of constant folding):

             (B>=5 AND B=5) OR (B=6 AND 5=5) OR (B=7 AND 5=6)
          -> B=5 OR B=6

   * Constant expressions used by indexes are evaluated only once.

   * `COUNT(*)' on a single table without a `WHERE' is retrieved
     directly from the table information for `MyISAM' and `MEMORY'
     tables. This is also done for any `NOT NULL' expression when used
     with only one table.

   * Early detection of invalid constant expressions. MySQL quickly
     detects that some *Note `SELECT': select. statements are
     impossible and returns no rows.

   * `HAVING' is merged with `WHERE' if you do not use `GROUP BY' or
     aggregate functions (`COUNT()', `MIN()', and so on).

   * For each table in a join, a simpler `WHERE' is constructed to get
     a fast `WHERE' evaluation for the table and also to skip rows as
     soon as possible.

   * All constant tables are read first before any other tables in the
     query. A constant table is any of the following:

        * An empty table or a table with one row.

        * A table that is used with a `WHERE' clause on a `PRIMARY KEY'
          or a `UNIQUE' index, where all index parts are compared to
          constant expressions and are defined as `NOT NULL'.

     All of the following tables are used as constant tables:

          SELECT * FROM t WHERE PRIMARY_KEY=1;
          SELECT * FROM t1,t2
            WHERE t1.PRIMARY_KEY=1 AND t2.PRIMARY_KEY=t1.id;

   * The best join combination for joining the tables is found by
     trying all possibilities. If all columns in `ORDER BY' and `GROUP
     BY' clauses come from the same table, that table is preferred
     first when joining.

   * If there is an `ORDER BY' clause and a different `GROUP BY'
     clause, or if the `ORDER BY' or `GROUP BY' contains columns from
     tables other than the first table in the join queue, a temporary
     table is created.

   * If you use the `SQL_SMALL_RESULT' option, MySQL uses an in-memory
     temporary table.

   * Each table index is queried, and the best index is used unless the
     optimizer believes that it is more efficient to use a table scan.
     At one time, a scan was used based on whether the best index
     spanned more than 30% of the table, but a fixed percentage no
     longer determines the choice between using an index or a scan. The
     optimizer now is more complex and bases its estimate on additional
     factors such as table size, number of rows, and I/O block size.

   * In some cases, MySQL can read rows from the index without even
     consulting the data file. If all columns used from the index are
     numeric, only the index tree is used to resolve the query.

   * Before each row is output, those that do not match the `HAVING'
     clause are skipped.

Some examples of queries that are very fast:

     SELECT COUNT(*) FROM TBL_NAME;

     SELECT MIN(KEY_PART1),MAX(KEY_PART1) FROM TBL_NAME;

     SELECT MAX(KEY_PART2) FROM TBL_NAME
       WHERE KEY_PART1=CONSTANT;

     SELECT ... FROM TBL_NAME
       ORDER BY KEY_PART1,KEY_PART2,... LIMIT 10;

     SELECT ... FROM TBL_NAME
       ORDER BY KEY_PART1 DESC, KEY_PART2 DESC, ... LIMIT 10;

MySQL resolves the following queries using only the index tree,
assuming that the indexed columns are numeric:

     SELECT KEY_PART1,KEY_PART2 FROM TBL_NAME WHERE KEY_PART1=VAL;

     SELECT COUNT(*) FROM TBL_NAME
       WHERE KEY_PART1=VAL1 AND KEY_PART2=VAL2;

     SELECT KEY_PART2 FROM TBL_NAME GROUP BY KEY_PART1;

The following queries use indexing to retrieve the rows in sorted order
without a separate sorting pass:

     SELECT ... FROM TBL_NAME
       ORDER BY KEY_PART1,KEY_PART2,... ;

     SELECT ... FROM TBL_NAME
       ORDER BY KEY_PART1 DESC, KEY_PART2 DESC, ... ;


File: manual.info,  Node: range-optimization,  Next: index-merge-optimization,  Prev: where-optimizations,  Up: select-optimization

8.3.1.3 Range Optimization
..........................

* Menu:

* range-access-single-part::     The Range Access Method for Single-Part Indexes
* range-access-multi-part::      The Range Access Method for Multiple-Part Indexes

The `range' access method uses a single index to retrieve a subset of
table rows that are contained within one or several index value
intervals. It can be used for a single-part or multiple-part index. The
following sections give a detailed description of how intervals are
extracted from the `WHERE' clause.


File: manual.info,  Node: range-access-single-part,  Next: range-access-multi-part,  Prev: range-optimization,  Up: range-optimization

8.3.1.4 The Range Access Method for Single-Part Indexes
.......................................................

For a single-part index, index value intervals can be conveniently
represented by corresponding conditions in the `WHERE' clause, so we
speak of _range conditions_ rather than `intervals.'

The definition of a range condition for a single-part index is as
follows:

   * For both `BTREE' and `HASH' indexes, comparison of a key part with
     a constant value is a range condition when using the `=', `<=>',
     `IN()', `IS NULL', or `IS NOT NULL' operators.

   * Additionally, for `BTREE' indexes, comparison of a key part with a
     constant value is a range condition when using the `>', `<', `>=',
     `<=', `BETWEEN', `!=', or `<>' operators, or `LIKE' comparisons if
     the argument to `LIKE' is a constant string that does not start
     with a wildcard character.

   * For all types of indexes, multiple range conditions combined with
     `OR' or `AND' form a range condition.

`Constant value' in the preceding descriptions means one of the
following:

   * A constant from the query string

   * A column of a `const' or `system' table from the same join

   * The result of an uncorrelated subquery

   * Any expression composed entirely from subexpressions of the
     preceding types

Here are some examples of queries with range conditions in the `WHERE'
clause:

     SELECT * FROM t1
       WHERE KEY_COL > 1
       AND KEY_COL < 10;

     SELECT * FROM t1
       WHERE KEY_COL = 1
       OR KEY_COL IN (15,18,20);

     SELECT * FROM t1
       WHERE KEY_COL LIKE 'ab%'
       OR KEY_COL BETWEEN 'bar' AND 'foo';

Note that some nonconstant values may be converted to constants during
the constant propagation phase.

MySQL tries to extract range conditions from the `WHERE' clause for
each of the possible indexes. During the extraction process, conditions
that cannot be used for constructing the range condition are dropped,
conditions that produce overlapping ranges are combined, and conditions
that produce empty ranges are removed.

Consider the following statement, where `key1' is an indexed column and
`nonkey' is not indexed:

     SELECT * FROM t1 WHERE
       (key1 < 'abc' AND (key1 LIKE 'abcde%' OR key1 LIKE '%b')) OR
       (key1 < 'bar' AND nonkey = 4) OR
       (key1 < 'uux' AND key1 > 'z');

The extraction process for key `key1' is as follows:

  1. Start with original `WHERE' clause:

          (key1 < 'abc' AND (key1 LIKE 'abcde%' OR key1 LIKE '%b')) OR
          (key1 < 'bar' AND nonkey = 4) OR
          (key1 < 'uux' AND key1 > 'z')

  2. Remove `nonkey = 4' and `key1 LIKE '%b'' because they cannot be
     used for a range scan. The correct way to remove them is to replace
     them with `TRUE', so that we do not miss any matching rows when
     doing the range scan. Having replaced them with `TRUE', we get:

          (key1 < 'abc' AND (key1 LIKE 'abcde%' OR TRUE)) OR
          (key1 < 'bar' AND TRUE) OR
          (key1 < 'uux' AND key1 > 'z')

  3. Collapse conditions that are always true or false:

        * `(key1 LIKE 'abcde%' OR TRUE)' is always true

        * `(key1 < 'uux' AND key1 > 'z')' is always false

     Replacing these conditions with constants, we get:

          (key1 < 'abc' AND TRUE) OR (key1 < 'bar' AND TRUE) OR (FALSE)

     Removing unnecessary `TRUE' and `FALSE' constants, we obtain:

          (key1 < 'abc') OR (key1 < 'bar')

  4. Combining overlapping intervals into one yields the final
     condition to be used for the range scan:

          (key1 < 'bar')

In general (and as demonstrated by the preceding example), the
condition used for a range scan is less restrictive than the `WHERE'
clause. MySQL performs an additional check to filter out rows that
satisfy the range condition but not the full `WHERE' clause.

The range condition extraction algorithm can handle nested `AND'/`OR'
constructs of arbitrary depth, and its output does not depend on the
order in which conditions appear in `WHERE' clause.

Currently, MySQL does not support merging multiple ranges for the
`range' access method for spatial indexes. To work around this
limitation, you can use a *Note `UNION': union. with identical *Note
`SELECT': select. statements, except that you put each spatial
predicate in a different *Note `SELECT': select.


File: manual.info,  Node: range-access-multi-part,  Prev: range-access-single-part,  Up: range-optimization

8.3.1.5 The Range Access Method for Multiple-Part Indexes
.........................................................

Range conditions on a multiple-part index are an extension of range
conditions for a single-part index. A range condition on a
multiple-part index restricts index rows to lie within one or several
key tuple intervals. Key tuple intervals are defined over a set of key
tuples, using ordering from the index.

For example, consider a multiple-part index defined as `key1(KEY_PART1,
KEY_PART2, KEY_PART3)', and the following set of key tuples listed in
key order:

     KEY_PART1  KEY_PART2  KEY_PART3
       NULL       1          'abc'
       NULL       1          'xyz'
       NULL       2          'foo'
        1         1          'abc'
        1         1          'xyz'
        1         2          'abc'
        2         1          'aaa'

The condition `KEY_PART1 = 1' defines this interval:

     (1,-inf,-inf) <= (KEY_PART1,KEY_PART2,KEY_PART3) < (1,+inf,+inf)

The interval covers the 4th, 5th, and 6th tuples in the preceding data
set and can be used by the range access method.

By contrast, the condition `KEY_PART3 = 'abc'' does not define a single
interval and cannot be used by the range access method.

The following descriptions indicate how range conditions work for
multiple-part indexes in greater detail.

   * For `HASH' indexes, each interval containing identical values can
     be used. This means that the interval can be produced only for
     conditions in the following form:

              KEY_PART1 CMP CONST1
          AND KEY_PART2 CMP CONST2
          AND ...
          AND KEY_PARTN CMP CONSTN;

     Here, CONST1, CONST2, ... are constants, CMP is one of the `=',
     `<=>', or `IS NULL' comparison operators, and the conditions cover
     all index parts.  (That is, there are N conditions, one for each
     part of an N-part index.) For example, the following is a range
     condition for a three-part `HASH' index:

          KEY_PART1 = 1 AND KEY_PART2 IS NULL AND KEY_PART3 = 'foo'

     For the definition of what is considered to be a constant, see
     *Note range-access-single-part::.

   * For a `BTREE' index, an interval might be usable for conditions
     combined with `AND', where each condition compares a key part with
     a constant value using `=', `<=>', `IS NULL', `>', `<', `>=', `<=',
     `!=', `<>', `BETWEEN', or `LIKE 'PATTERN'' (where `'PATTERN'' does
     not start with a wildcard). An interval can be used as long as it
     is possible to determine a single key tuple containing all rows
     that match the condition (or two intervals if `<>' or `!=' is
     used).

     The optimizer attempts to use additional key parts to determine
     the interval as long as the comparison operator is `=', `<=>', or
     `IS NULL'. If the operator is `>', `<', `>=', `<=', `!=', `<>',
     `BETWEEN', or `LIKE', the optimizer uses it but considers no more
     key parts. For the following expression, the optimizer uses `='
     from the first comparison. It also uses `>=' from the second
     comparison but considers no further key parts and does not use the
     third comparison for interval construction:

          KEY_PART1 = 'foo' AND KEY_PART2 >= 10 AND KEY_PART3 > 10

     The single interval is:

          ('foo',10,-inf) < (KEY_PART1,KEY_PART2,KEY_PART3) < ('foo',+inf,+inf)

     It is possible that the created interval contains more rows than
     the initial condition. For example, the preceding interval
     includes the value `('foo', 11, 0)', which does not satisfy the
     original condition.

   * If conditions that cover sets of rows contained within intervals
     are combined with `OR', they form a condition that covers a set of
     rows contained within the union of their intervals. If the
     conditions are combined with `AND', they form a condition that
     covers a set of rows contained within the intersection of their
     intervals. For example, for this condition on a two-part index:

          (KEY_PART1 = 1 AND KEY_PART2 < 2) OR (KEY_PART1 > 5)

     The intervals are:

          (1,-inf) < (KEY_PART1,KEY_PART2) < (1,2)
          (5,-inf) < (KEY_PART1,KEY_PART2)

     In this example, the interval on the first line uses one key part
     for the left bound and two key parts for the right bound. The
     interval on the second line uses only one key part. The `key_len'
     column in the *Note `EXPLAIN': explain. output indicates the
     maximum length of the key prefix used.

     In some cases, `key_len' may indicate that a key part was used,
     but that might be not what you would expect. Suppose that
     KEY_PART1 and KEY_PART2 can be `NULL'. Then the `key_len' column
     displays two key part lengths for the following condition:

          KEY_PART1 >= 1 AND KEY_PART2 < 2

     But, in fact, the condition is converted to this:

          KEY_PART1 >= 1 AND KEY_PART2 IS NOT NULL

*Note range-access-single-part::, describes how optimizations are
performed to combine or eliminate intervals for range conditions on a
single-part index.  Analogous steps are performed for range conditions
on multiple-part indexes.


File: manual.info,  Node: index-merge-optimization,  Next: condition-pushdown-optimization,  Prev: range-optimization,  Up: select-optimization

8.3.1.6 Index Merge Optimization
................................

* Menu:

* index-merge-intersection::     The Index Merge Intersection Access Algorithm
* index-merge-union::            The Index Merge Union Access Algorithm
* index-merge-sort-union::       The Index Merge Sort-Union Access Algorithm

The _Index Merge_ method is used to retrieve rows with several `range'
scans and to merge their results into one. The merge can produce unions,
intersections, or unions-of-intersections of its underlying scans. This
access method merges index scans from a single table; it does not merge
scans across multiple tables.

*Note*:

If you have upgraded from a previous version of MySQL, you should be
aware that this type of join optimization is first introduced in MySQL
5.0, and represents a significant change in behavior with regard to
indexes. (Formerly, MySQL was able to use at most only one index for
each referenced table.)

In *Note `EXPLAIN': explain. output, the Index Merge method appears as
`index_merge' in the `type' column. In this case, the `key' column
contains a list of indexes used, and `key_len' contains a list of the
longest key parts for those indexes.

Examples:

     SELECT * FROM TBL_NAME WHERE KEY1 = 10 OR KEY2 = 20;

     SELECT * FROM TBL_NAME
       WHERE (KEY1 = 10 OR KEY2 = 20) AND NON_KEY=30;

     SELECT * FROM t1, t2
       WHERE (t1.KEY1 IN (1,2) OR t1.KEY2 LIKE 'VALUE%')
       AND t2.KEY1=t1.SOME_COL;

     SELECT * FROM t1, t2
       WHERE t1.KEY1=1
       AND (t2.KEY1=t1.SOME_COL OR t2.KEY2=t1.SOME_COL2);

The Index Merge method has several access algorithms (seen in the
`Extra' field of *Note `EXPLAIN': explain. output):

   * `Using intersect(...)'

   * `Using union(...)'

   * `Using sort_union(...)'

The following sections describe these methods in greater detail.

*Note*:

The Index Merge optimization algorithm has the following known
deficiencies:

   * If a range scan is possible on some key, the optimizer will not
     consider using Index Merge Union or Index Merge Sort-Union
     algorithms. For example, consider this query:

          SELECT * FROM t1 WHERE (goodkey1 < 10 OR goodkey2 < 20) AND badkey < 30;

     For this query, two plans are possible:

        * An Index Merge scan using the `(goodkey1 < 10 OR goodkey2 <
          20)' condition.

        * A range scan using the `badkey < 30' condition.

     However, the optimizer considers only the second plan.

   * If your query has a complex `WHERE' clause with deep `AND'/`OR'
     nesting and MySQL doesn't choose the optimal plan, try
     distributing terms using the following identity laws:

          (X AND Y) OR Z = (X OR Z) AND (Y OR Z)
          (X OR Y) AND Z = (X AND Z) OR (Y AND Z)

   * Index Merge is not applicable to full-text indexes. We plan to
     extend it to cover these in a future MySQL release.

The choice between different possible variants of the Index Merge
access method and other access methods is based on cost estimates of
various available options.


File: manual.info,  Node: index-merge-intersection,  Next: index-merge-union,  Prev: index-merge-optimization,  Up: index-merge-optimization

8.3.1.7 The Index Merge Intersection Access Algorithm
.....................................................

This access algorithm can be employed when a `WHERE' clause was
converted to several range conditions on different keys combined with
`AND', and each condition is one of the following:

   * In this form, where the index has exactly N parts (that is, all
     index parts are covered):

          KEY_PART1=CONST1 AND KEY_PART2=CONST2 ... AND KEY_PARTN=CONSTN

   * Any range condition over a primary key of an `InnoDB' or `BDB'
     table.

Examples:

     SELECT * FROM INNODB_TABLE WHERE PRIMARY_KEY < 10 AND KEY_COL1=20;

     SELECT * FROM TBL_NAME
       WHERE (KEY1_PART1=1 AND KEY1_PART2=2) AND KEY2=2;

The Index Merge intersection algorithm performs simultaneous scans on
all used indexes and produces the intersection of row sequences that it
receives from the merged index scans.

If all columns used in the query are covered by the used indexes, full
table rows are not retrieved (*Note `EXPLAIN': explain. output contains
`Using index' in `Extra' field in this case). Here is an example of
such a query:

     SELECT COUNT(*) FROM t1 WHERE key1=1 AND key2=1;

If the used indexes don't cover all columns used in the query, full
rows are retrieved only when the range conditions for all used keys are
satisfied.

If one of the merged conditions is a condition over a primary key of an
`InnoDB' or `BDB' table, it is not used for row retrieval, but is used
to filter out rows retrieved using other conditions.


File: manual.info,  Node: index-merge-union,  Next: index-merge-sort-union,  Prev: index-merge-intersection,  Up: index-merge-optimization

8.3.1.8 The Index Merge Union Access Algorithm
..............................................

The applicability criteria for this algorithm are similar to those for
the Index Merge method intersection algorithm. The algorithm can be
employed when the table's `WHERE' clause was converted to several range
conditions on different keys combined with `OR', and each condition is
one of the following:

   * In this form, where the index has exactly N parts (that is, all
     index parts are covered):

          KEY_PART1=CONST1 AND KEY_PART2=CONST2 ... AND KEY_PARTN=CONSTN

   * Any range condition over a primary key of an `InnoDB' or `BDB'
     table.

   * A condition for which the Index Merge method intersection
     algorithm is applicable.

Examples:

     SELECT * FROM t1 WHERE KEY1=1 OR KEY2=2 OR KEY3=3;

     SELECT * FROM INNODB_TABLE WHERE (KEY1=1 AND KEY2=2) OR
       (KEY3='foo' AND KEY4='bar') AND KEY5=5;


File: manual.info,  Node: index-merge-sort-union,  Prev: index-merge-union,  Up: index-merge-optimization

8.3.1.9 The Index Merge Sort-Union Access Algorithm
...................................................

This access algorithm is employed when the `WHERE' clause was converted
to several range conditions combined by `OR', but for which the Index
Merge method union algorithm is not applicable.

Examples:

     SELECT * FROM TBL_NAME WHERE KEY_COL1 < 10 OR KEY_COL2 < 20;

     SELECT * FROM TBL_NAME
       WHERE (KEY_COL1 > 10 OR KEY_COL2 = 20) AND NONKEY_COL=30;

The difference between the sort-union algorithm and the union algorithm
is that the sort-union algorithm must first fetch row IDs for all rows
and sort them before returning any rows.


File: manual.info,  Node: condition-pushdown-optimization,  Next: is-null-optimization,  Prev: index-merge-optimization,  Up: select-optimization

8.3.1.10 Engine Condition Pushdown Optimization
...............................................

This optimization improves the efficiency of direct comparisons between
a nonindexed column and a constant. In such cases, the condition is
`pushed down' to the storage engine for evaluation. This optimization
can be used only by the *Note `NDBCLUSTER': mysql-cluster. storage
engine.

For MySQL Cluster, this optimization can eliminate the need to send
nonmatching rows over the network between the cluster's data nodes and
the MySQL Server that issued the query, and can speed up queries where
it is used by a factor of 5 to 10 times over cases where condition
pushdown could be but is not used.

Suppose that a MySQL Cluster table is defined as follows:

     CREATE TABLE t1 (
         a INT,
         b INT,
         KEY(a)
     ) ENGINE=NDBCLUSTER;

Condition pushdown can be used with queries such as the one shown here,
which includes a comparison between a nonindexed column and a constant:

     SELECT a, b FROM t1 WHERE b = 10;

The use of condition pushdown can be seen in the output of *Note
`EXPLAIN': explain.:

     mysql> EXPLAIN SELECT a,b FROM t1 WHERE b = 10\G
     *************************** 1. row ***************************
                id: 1
       select_type: SIMPLE
             table: t1
              type: ALL
     possible_keys: NULL
               key: NULL
           key_len: NULL
               ref: NULL
              rows: 10
             Extra: Using where with pushed condition

However, condition pushdown _cannot_ be used with either of these two
queries:

     SELECT a,b FROM t1 WHERE a = 10;
     SELECT a,b FROM t1 WHERE b + 1 = 10;

Condition pushdown is not applicable to the first query because an
index exists on column `a'. (An index access method would be more
efficient and so would be chosen in preference to condition pushdown.)
Condition pushdown cannot be employed for the second query because the
comparison involving the nonindexed column `b' is indirect. (However,
condition pushdown could be applied if you were to reduce `b + 1 = 10'
to `b = 9' in the `WHERE' clause.)

Condition pushdown may also be employed when an indexed column is
compared with a constant using a `>' or `<' operator:

     mysql> EXPLAIN SELECT a, b FROM t1 WHERE a < 2\G
     *************************** 1. row ***************************
                id: 1
       select_type: SIMPLE
             table: t1
              type: range
     possible_keys: a
               key: a
           key_len: 5
               ref: NULL
              rows: 2
             Extra: Using where with pushed condition

Other supported comparisons for condition pushdown include the
following:

   * `COLUMN [NOT] LIKE PATTERN'

     PATTERN must be a string literal containing the pattern to be
     matched; for syntax, see *Note string-comparison-functions::.

   * `COLUMN IS [NOT] NULL'

   * `COLUMN IN (VALUE_LIST)'

     Each item in the VALUE_LIST must be a constant, literal value.

   * `COLUMN BETWEEN CONSTANT1 AND CONSTANT2'

     CONSTANT1 and CONSTANT2 must each be a constant, literal value.

In all of the cases in the preceding list, it is possible for the
condition to be converted into the form of one or more direct
comparisons between a column and a constant.

Engine condition pushdown is disabled by default. To enable it at
server startup, set the `engine_condition_pushdown' system variable.
For example, in a `my.cnf' file, use these lines:

     [mysqld]
     engine_condition_pushdown=1

At runtime, enable condition pushdown with either of the following
statements:

     SET engine_condition_pushdown=ON;

     SET engine_condition_pushdown=1;

Limitations

Engine condition pushdown is subject to the following limitations:

   * Condition pushdown is supported only by the *Note `NDBCLUSTER':
     mysql-cluster. storage engine.

   * Columns may be compared with constants only; however, this
     includes expressions which evaluate to constant values.

   * Columns used in comparisons cannot be of any of the *Note `BLOB':
     blob. or *Note `TEXT': blob. types.

   * A string value to be compared with a column must use the same
     collation as the column.

   * Joins are not directly supported; conditions involving multiple
     tables are pushed separately where possible. Use *Note `EXPLAIN
     EXTENDED': explain. to determine which conditions are actually
     pushed down.


File: manual.info,  Node: is-null-optimization,  Next: left-join-optimization,  Prev: condition-pushdown-optimization,  Up: select-optimization

8.3.1.11 `IS NULL' Optimization
...............................

MySQL can perform the same optimization on COL_NAME `IS NULL' that it
can use for COL_NAME `=' CONSTANT_VALUE. For example, MySQL can use
indexes and ranges to search for `NULL' with `IS NULL'.

Examples:

     SELECT * FROM TBL_NAME WHERE KEY_COL IS NULL;

     SELECT * FROM TBL_NAME WHERE KEY_COL <=> NULL;

     SELECT * FROM TBL_NAME
       WHERE KEY_COL=CONST1 OR KEY_COL=CONST2 OR KEY_COL IS NULL;

If a `WHERE' clause includes a COL_NAME `IS NULL' condition for a
column that is declared as `NOT NULL', that expression is optimized
away. This optimization does not occur in cases when the column might
produce `NULL' anyway; for example, if it comes from a table on the
right side of a `LEFT JOIN'.

MySQL can also optimize the combination `COL_NAME = EXPR OR COL_NAME IS
NULL', a form that is common in resolved subqueries.  *Note `EXPLAIN':
explain. shows `ref_or_null' when this optimization is used.

This optimization can handle one `IS NULL' for any key part.

Some examples of queries that are optimized, assuming that there is an
index on columns `a' and `b' of table `t2':

     SELECT * FROM t1 WHERE t1.a=EXPR OR t1.a IS NULL;

     SELECT * FROM t1, t2 WHERE t1.a=t2.a OR t2.a IS NULL;

     SELECT * FROM t1, t2
       WHERE (t1.a=t2.a OR t2.a IS NULL) AND t2.b=t1.b;

     SELECT * FROM t1, t2
       WHERE t1.a=t2.a AND (t2.b=t1.b OR t2.b IS NULL);

     SELECT * FROM t1, t2
       WHERE (t1.a=t2.a AND t2.a IS NULL AND ...)
       OR (t1.a=t2.a AND t2.a IS NULL AND ...);

`ref_or_null' works by first doing a read on the reference key, and
then a separate search for rows with a `NULL' key value.

Note that the optimization can handle only one `IS NULL' level. In the
following query, MySQL uses key lookups only on the expression
`(t1.a=t2.a AND t2.a IS NULL)' and is not able to use the key part on
`b':

     SELECT * FROM t1, t2
       WHERE (t1.a=t2.a AND t2.a IS NULL)
       OR (t1.b=t2.b AND t2.b IS NULL);


File: manual.info,  Node: left-join-optimization,  Next: nested-loop-joins,  Prev: is-null-optimization,  Up: select-optimization

8.3.1.12 `LEFT JOIN' and `RIGHT JOIN' Optimization
..................................................

MySQL implements an `A LEFT JOIN B join_condition' as follows:

   * Table B is set to depend on table A and all tables on which A
     depends.

   * Table A is set to depend on all tables (except B) that are used in
     the `LEFT JOIN' condition.

   * The `LEFT JOIN' condition is used to decide how to retrieve rows
     from table B. (In other words, any condition in the `WHERE' clause
     is not used.)

   * All standard join optimizations are performed, with the exception
     that a table is always read after all tables on which it depends.
     If there is a circular dependence, MySQL issues an error.

   * All standard `WHERE' optimizations are performed.

   * If there is a row in A that matches the `WHERE' clause, but there
     is no row in B that matches the `ON' condition, an extra B row is
     generated with all columns set to `NULL'.

   * If you use `LEFT JOIN' to find rows that do not exist in some
     table and you have the following test: `COL_NAME IS NULL' in the
     `WHERE' part, where COL_NAME is a column that is declared as `NOT
     NULL', MySQL stops searching for more rows (for a particular key
     combination) after it has found one row that matches the `LEFT
     JOIN' condition.

The implementation of `RIGHT JOIN' is analogous to that of `LEFT JOIN'
with the roles of the tables reversed.

The join optimizer calculates the order in which tables should be
joined. The table read order forced by `LEFT JOIN' or `STRAIGHT_JOIN'
helps the join optimizer do its work much more quickly, because there
are fewer table permutations to check. Note that this means that if you
do a query of the following type, MySQL does a full scan on `b' because
the `LEFT JOIN' forces it to be read before `d':

     SELECT *
       FROM a JOIN b LEFT JOIN c ON (c.key=a.key) LEFT JOIN d ON (d.key=a.key)
       WHERE b.key=d.key;

The fix in this case is reverse the order in which `a' and `b' are
listed in the `FROM' clause:

     SELECT *
       FROM b JOIN a LEFT JOIN c ON (c.key=a.key) LEFT JOIN d ON (d.key=a.key)
       WHERE b.key=d.key;

For a `LEFT JOIN', if the `WHERE' condition is always false for the
generated `NULL' row, the `LEFT JOIN' is changed to a normal join. For
example, the `WHERE' clause would be false in the following query if
`t2.column1' were `NULL':

     SELECT * FROM t1 LEFT JOIN t2 ON (column1) WHERE t2.column2=5;

Therefore, it is safe to convert the query to a normal join:

     SELECT * FROM t1, t2 WHERE t2.column2=5 AND t1.column1=t2.column1;

This can be made faster because MySQL can use table `t2' before table
`t1' if doing so would result in a better query plan. To provide a hint
about the table join order, use `STRAIGHT_JOIN'. (See *Note select::.)


File: manual.info,  Node: nested-loop-joins,  Next: nested-join-optimization,  Prev: left-join-optimization,  Up: select-optimization

8.3.1.13 Nested-Loop Join Algorithms
....................................

MySQL executes joins between tables using a nested-loop algorithm or
variations on it.

*Nested-Loop Join Algorithm*

A simple nested-loop join (NLJ) algorithm reads rows from the first
table in a loop one at a time, passing each row to a nested loop that
processes the next table in the join. This process is repeated as many
times as there remain tables to be joined.

Assume that a join between three tables `t1', `t2', and `t3' is to be
executed using the following join types:

     Table   Join Type
     t1      range
     t2      ref
     t3      ALL

If a simple NLJ algorithm is used, the join is processed like this:

     for each row in t1 matching range {
       for each row in t2 matching reference key {
         for each row in t3 {
           if row satisfies join conditions,
           send to client
         }
       }
     }

Because the NLJ algorithm passes rows one at a time from outer loops to
inner loops, it typically reads tables processed in the inner loops
many times.

*Block Nested-Loop Join Algorithm*

A Block Nested-Loop (BNL) Join algorithm uses buffering of rows read in
outer loops to reduce the number of times that tables in inner loops
must be read. For example, if 10 rows are read into a buffer and the
buffer is passed to the next inner loop, each row read in the inner
loop can be compared against all 10 rows in the buffer. The reduces the
number of times the inner table must be read by an order of magnitude.

MySQL uses join buffering under these conditions:

   * The `join_buffer_size' system variable determines the size of each
     join buffer.

   * Join buffering can be used when the join is of type `ALL' or
     `index' (in other words, when no possible keys can be used, and a
     full scan is done, of either the data or index rows,
     respectively), or `range'.

   * One buffer is allocated for each join that can be buffered, so a
     given query might be processed using multiple join buffers.

   * A join buffer is never allocated for the first nonconst table,
     even if it would be of type `ALL' or `index'.

   * A join buffer is allocated prior to executing the join and freed
     after the query is done.

   * Only columns of interest to the join are stored in the join
     buffer, not whole rows.

For the example join described previously for the NLJ algorithm
(without buffering), the join is done as follow using join buffering:

     for each row in t1 matching range {
       for each row in t2 matching reference key {
         store used columns from t1, t2 in join buffer
         if buffer is full {
           for each row in t3 {
             for each t1, t2 combination in join buffer {
               if row satisfies join conditions,
               send to client
             }
           }
           empty buffer
         }
       }
     }

     if buffer is not empty {
       for each row in t3 {
         for each t1, t2 combination in join buffer {
           if row satisfies join conditions,
           send to client
         }
       }
     }

If S is the size of each stored `t1', `t2' combination is the join
buffer and C is the number of combinations in the buffer, the number of
times table `t3' is scanned is:

     (S * C)/join_buffer_size + 1

The number of `t3' scans decreases as the value of `join_buffer_size'
increases, up to the point when `join_buffer_size' is large enough to
hold all previous row combinations. At that point, there is no speed to
be gained by making it larger.


File: manual.info,  Node: nested-join-optimization,  Next: outer-join-simplification,  Prev: nested-loop-joins,  Up: select-optimization

8.3.1.14 Nested Join Optimization
.................................

As of MySQL 5.0.1, the syntax for expressing joins permits nested
joins. The following discussion refers to the join syntax described in
*Note join::.

The syntax of TABLE_FACTOR is extended in comparison with the SQL
Standard. The latter accepts only TABLE_REFERENCE, not a list of them
inside a pair of parentheses. This is a conservative extension if we
consider each comma in a list of TABLE_REFERENCE items as equivalent to
an inner join. For example:

     SELECT * FROM t1 LEFT JOIN (t2, t3, t4)
                      ON (t2.a=t1.a AND t3.b=t1.b AND t4.c=t1.c)

is equivalent to:

     SELECT * FROM t1 LEFT JOIN (t2 CROSS JOIN t3 CROSS JOIN t4)
                      ON (t2.a=t1.a AND t3.b=t1.b AND t4.c=t1.c)

In MySQL, `CROSS JOIN' is a syntactic equivalent to `INNER JOIN' (they
can replace each other). In standard SQL, they are not equivalent.
`INNER JOIN' is used with an `ON' clause; `CROSS JOIN' is used
otherwise.

In versions of MySQL prior to 5.0.1, parentheses in TABLE_REFERENCES
were just omitted and all join operations were grouped to the left. In
general, parentheses can be ignored in join expressions containing only
inner join operations.

After removing parentheses and grouping operations to the left, the
join expression:

     t1 LEFT JOIN (t2 LEFT JOIN t3 ON t2.b=t3.b OR t2.b IS NULL)
        ON t1.a=t2.a

transforms into the expression:

     (t1 LEFT JOIN t2 ON t1.a=t2.a) LEFT JOIN t3
         ON t2.b=t3.b OR t2.b IS NULL

Yet, the two expressions are not equivalent. To see this, suppose that
the tables `t1', `t2', and `t3' have the following state:

   * Table `t1' contains rows `(1)', `(2)'

   * Table `t2' contains row `(1,101)'

   * Table `t3' contains row `(101)'

In this case, the first expression returns a result set including the
rows `(1,1,101,101)', `(2,NULL,NULL,NULL)', whereas the second
expression returns the rows `(1,1,101,101)', `(2,NULL,NULL,101)':

     mysql> SELECT *
         -> FROM t1
         ->      LEFT JOIN
         ->      (t2 LEFT JOIN t3 ON t2.b=t3.b OR t2.b IS NULL)
         ->      ON t1.a=t2.a;
     +------+------+------+------+
     | a    | a    | b    | b    |
     +------+------+------+------+
     |    1 |    1 |  101 |  101 |
     |    2 | NULL | NULL | NULL |
     +------+------+------+------+

     mysql> SELECT *
         -> FROM (t1 LEFT JOIN t2 ON t1.a=t2.a)
         ->      LEFT JOIN t3
         ->      ON t2.b=t3.b OR t2.b IS NULL;
     +------+------+------+------+
     | a    | a    | b    | b    |
     +------+------+------+------+
     |    1 |    1 |  101 |  101 |
     |    2 | NULL | NULL |  101 |
     +------+------+------+------+

In the following example, an outer join operation is used together with
an inner join operation:

     t1 LEFT JOIN (t2, t3) ON t1.a=t2.a

That expression cannot be transformed into the following expression:

     t1 LEFT JOIN t2 ON t1.a=t2.a, t3.

For the given table states, the two expressions return different sets
of rows:

     mysql> SELECT *
         -> FROM t1 LEFT JOIN (t2, t3) ON t1.a=t2.a;
     +------+------+------+------+
     | a    | a    | b    | b    |
     +------+------+------+------+
     |    1 |    1 |  101 |  101 |
     |    2 | NULL | NULL | NULL |
     +------+------+------+------+

     mysql> SELECT *
         -> FROM t1 LEFT JOIN t2 ON t1.a=t2.a, t3;
     +------+------+------+------+
     | a    | a    | b    | b    |
     +------+------+------+------+
     |    1 |    1 |  101 |  101 |
     |    2 | NULL | NULL |  101 |
     +------+------+------+------+

Therefore, if we omit parentheses in a join expression with outer join
operators, we might change the result set for the original expression.

More exactly, we cannot ignore parentheses in the right operand of the
left outer join operation and in the left operand of a right join
operation. In other words, we cannot ignore parentheses for the inner
table expressions of outer join operations. Parentheses for the other
operand (operand for the outer table) can be ignored.

The following expression:

     (t1,t2) LEFT JOIN t3 ON P(t2.b,t3.b)

is equivalent to this expression:

     t1, t2 LEFT JOIN t3 ON P(t2.b,t3.b)

for any tables `t1,t2,t3' and any condition `P' over attributes `t2.b'
and `t3.b'.

Whenever the order of execution of the join operations in a join
expression (JOIN_TABLE) is not from left to right, we talk about nested
joins. Consider the following queries:

     SELECT * FROM t1 LEFT JOIN (t2 LEFT JOIN t3 ON t2.b=t3.b) ON t1.a=t2.a
       WHERE t1.a > 1

     SELECT * FROM t1 LEFT JOIN (t2, t3) ON t1.a=t2.a
       WHERE (t2.b=t3.b OR t2.b IS NULL) AND t1.a > 1

Those queries are considered to contain these nested joins:

     t2 LEFT JOIN t3 ON t2.b=t3.b
     t2, t3

The nested join is formed in the first query with a left join
operation, whereas in the second query it is formed with an inner join
operation.

In the first query, the parentheses can be omitted: The grammatical
structure of the join expression will dictate the same order of
execution for join operations. For the second query, the parentheses
cannot be omitted, although the join expression here can be interpreted
unambiguously without them.  (In our extended syntax the parentheses in
`(t2, t3)' of the second query are required, although theoretically the
query could be parsed without them: We still would have unambiguous
syntactical structure for the query because `LEFT JOIN' and `ON' would
play the role of the left and right delimiters for the expression
`(t2,t3)'.)

The preceding examples demonstrate these points:

   * For join expressions involving only inner joins (and not outer
     joins), parentheses can be removed. You can remove parentheses and
     evaluate left to right (or, in fact, you can evaluate the tables
     in any order).

   * The same is not true, in general, for outer joins or for outer
     joins mixed with inner joins. Removal of parentheses may change
     the result.

Queries with nested outer joins are executed in the same pipeline
manner as queries with inner joins. More exactly, a variation of the
nested-loop join algorithm is exploited.  Recall by what algorithmic
schema the nested-loop join executes a query. Suppose that we have a
join query over 3 tables `T1,T2,T3' of the form:

     SELECT * FROM T1 INNER JOIN T2 ON P1(T1,T2)
                      INNER JOIN T3 ON P2(T2,T3)
       WHERE P(T1,T2,T3).

Here, `P1(T1,T2)' and `P2(T3,T3)' are some join conditions (on
expressions), whereas `P(t1,t2,t3)' is a condition over columns of
tables `T1,T2,T3'.

The nested-loop join algorithm would execute this query in the
following manner:

     FOR each row t1 in T1 {
       FOR each row t2 in T2 such that P1(t1,t2) {
         FOR each row t3 in T3 such that P2(t2,t3) {
           IF P(t1,t2,t3) {
              t:=t1||t2||t3; OUTPUT t;
           }
         }
       }
     }

The notation `t1||t2||t3' means `a row constructed by concatenating the
columns of rows `t1', `t2', and `t3'.' In some of the following
examples, `NULL' where a row name appears means that `NULL' is used for
each column of that row. For example, `t1||t2||NULL' means `a row
constructed by concatenating the columns of rows `t1' and `t2', and
`NULL' for each column of `t3'.'

Now let's consider a query with nested outer joins:

     SELECT * FROM T1 LEFT JOIN
                   (T2 LEFT JOIN T3 ON P2(T2,T3))
                   ON P1(T1,T2)
       WHERE P(T1,T2,T3).

For this query, we modify the nested-loop pattern to get:

     FOR each row t1 in T1 {
       BOOL f1:=FALSE;
       FOR each row t2 in T2 such that P1(t1,t2) {
         BOOL f2:=FALSE;
         FOR each row t3 in T3 such that P2(t2,t3) {
           IF P(t1,t2,t3) {
             t:=t1||t2||t3; OUTPUT t;
           }
           f2=TRUE;
           f1=TRUE;
         }
         IF (!f2) {
           IF P(t1,t2,NULL) {
             t:=t1||t2||NULL; OUTPUT t;
           }
           f1=TRUE;
         }
       }
       IF (!f1) {
         IF P(t1,NULL,NULL) {
           t:=t1||NULL||NULL; OUTPUT t;
         }
       }
     }

In general, for any nested loop for the first inner table in an outer
join operation, a flag is introduced that is turned off before the loop
and is checked after the loop. The flag is turned on when for the
current row from the outer table a match from the table representing
the inner operand is found.  If at the end of the loop cycle the flag
is still off, no match has been found for the current row of the outer
table.  In this case, the row is complemented by `NULL' values for the
columns of the inner tables. The result row is passed to the final
check for the output or into the next nested loop, but only if the row
satisfies the join condition of all embedded outer joins.

In our example, the outer join table expressed by the following
expression is embedded:

     (T2 LEFT JOIN T3 ON P2(T2,T3))

Note that for the query with inner joins, the optimizer could choose a
different order of nested loops, such as this one:

     FOR each row t3 in T3 {
       FOR each row t2 in T2 such that P2(t2,t3) {
         FOR each row t1 in T1 such that P1(t1,t2) {
           IF P(t1,t2,t3) {
              t:=t1||t2||t3; OUTPUT t;
           }
         }
       }
     }

For the queries with outer joins, the optimizer can choose only such an
order where loops for outer tables precede loops for inner tables.
Thus, for our query with outer joins, only one nesting order is
possible. For the following query, the optimizer will evaluate two
different nestings:

     SELECT * T1 LEFT JOIN (T2,T3) ON P1(T1,T2) AND P2(T1,T3)
       WHERE P(T1,T2,T3)

The nestings are these:

     FOR each row t1 in T1 {
       BOOL f1:=FALSE;
       FOR each row t2 in T2 such that P1(t1,t2) {
         FOR each row t3 in T3 such that P2(t1,t3) {
           IF P(t1,t2,t3) {
             t:=t1||t2||t3; OUTPUT t;
           }
           f1:=TRUE
         }
       }
       IF (!f1) {
         IF P(t1,NULL,NULL) {
           t:=t1||NULL||NULL; OUTPUT t;
         }
       }
     }

and:

     FOR each row t1 in T1 {
       BOOL f1:=FALSE;
       FOR each row t3 in T3 such that P2(t1,t3) {
         FOR each row t2 in T2 such that P1(t1,t2) {
           IF P(t1,t2,t3) {
             t:=t1||t2||t3; OUTPUT t;
           }
           f1:=TRUE
         }
       }
       IF (!f1) {
         IF P(t1,NULL,NULL) {
           t:=t1||NULL||NULL; OUTPUT t;
         }
       }
     }

In both nestings, `T1' must be processed in the outer loop because it
is used in an outer join.  `T2' and `T3' are used in an inner join, so
that join must be processed in the inner loop.  However, because the
join is an inner join, `T2' and `T3' can be processed in either order.

When discussing the nested-loop algorithm for inner joins, we omitted
some details whose impact on the performance of query execution may be
huge. We did not mention so-called `pushed-down' conditions. Suppose
that our `WHERE' condition `P(T1,T2,T3)' can be represented by a
conjunctive formula:

     P(T1,T2,T2) = C1(T1) AND C2(T2) AND C3(T3).

In this case, MySQL actually uses the following nested-loop schema for
the execution of the query with inner joins:

     FOR each row t1 in T1 such that C1(t1) {
       FOR each row t2 in T2 such that P1(t1,t2) AND C2(t2)  {
         FOR each row t3 in T3 such that P2(t2,t3) AND C3(t3) {
           IF P(t1,t2,t3) {
              t:=t1||t2||t3; OUTPUT t;
           }
         }
       }
     }

You see that each of the conjuncts `C1(T1)', `C2(T2)', `C3(T3)' are
pushed out of the most inner loop to the most outer loop where it can
be evaluated. If `C1(T1)' is a very restrictive condition, this
condition pushdown may greatly reduce the number of rows from table `T1'
passed to the inner loops. As a result, the execution time for the
query may improve immensely.

For a query with outer joins, the `WHERE' condition is to be checked
only after it has been found that the current row from the outer table
has a match in the inner tables. Thus, the optimization of pushing
conditions out of the inner nested loops cannot be applied directly to
queries with outer joins. Here we have to introduce conditional
pushed-down predicates guarded by the flags that are turned on when a
match has been encountered.

For our example with outer joins with:

     P(T1,T2,T3)=C1(T1) AND C(T2) AND C3(T3)

the nested-loop schema using guarded pushed-down conditions looks like
this:

     FOR each row t1 in T1 such that C1(t1) {
       BOOL f1:=FALSE;
       FOR each row t2 in T2
           such that P1(t1,t2) AND (f1?C2(t2):TRUE) {
         BOOL f2:=FALSE;
         FOR each row t3 in T3
             such that P2(t2,t3) AND (f1&&f2?C3(t3):TRUE) {
           IF (f1&&f2?TRUE:(C2(t2) AND C3(t3))) {
             t:=t1||t2||t3; OUTPUT t;
           }
           f2=TRUE;
           f1=TRUE;
         }
         IF (!f2) {
           IF (f1?TRUE:C2(t2) && P(t1,t2,NULL)) {
             t:=t1||t2||NULL; OUTPUT t;
           }
           f1=TRUE;
         }
       }
       IF (!f1 && P(t1,NULL,NULL)) {
           t:=t1||NULL||NULL; OUTPUT t;
       }
     }

In general, pushed-down predicates can be extracted from join
conditions such as `P1(T1,T2)' and `P(T2,T3)'. In this case, a
pushed-down predicate is guarded also by a flag that prevents checking
the predicate for the `NULL'-complemented row generated by the
corresponding outer join operation.

Note that access by key from one inner table to another in the same
nested join is prohibited if it is induced by a predicate from the
`WHERE' condition. (We could use conditional key access in this case,
but this technique is not employed yet in MySQL 5.0.)


File: manual.info,  Node: outer-join-simplification,  Next: order-by-optimization,  Prev: nested-join-optimization,  Up: select-optimization

8.3.1.15 Outer Join Simplification
..................................

Table expressions in the `FROM' clause of a query are simplified in
many cases.

At the parser stage, queries with right outer joins operations are
converted to equivalent queries containing only left join operations.
In the general case, the conversion is performed according to the
following rule:

     (T1, ...) RIGHT JOIN (T2,...) ON P(T1,...,T2,...) =
     (T2, ...) LEFT JOIN (T1,...) ON P(T1,...,T2,...)

All inner join expressions of the form `T1 INNER JOIN T2 ON P(T1,T2)'
are replaced by the list `T1,T2', `P(T1,T2)' being joined as a conjunct
to the `WHERE' condition (or to the join condition of the embedding
join, if there is any).

When the optimizer evaluates plans for join queries with outer join
operation, it takes into consideration only the plans where, for each
such operation, the outer tables are accessed before the inner tables.
The optimizer options are limited because only such plans enables us to
execute queries with outer joins operations by the nested loop schema.

Suppose that we have a query of the form:

     SELECT * T1 LEFT JOIN T2 ON P1(T1,T2)
       WHERE P(T1,T2) AND R(T2)

with `R(T2)' narrowing greatly the number of matching rows from table
`T2'. If we executed the query as it is, the optimizer would have no
other choice besides to access table `T1' before table `T2' that may
lead to a very inefficient execution plan.

Fortunately, MySQL converts such a query into a query without an outer
join operation if the `WHERE' condition is null-rejected. A condition
is called null-rejected for an outer join operation if it evaluates to
`FALSE' or to `UNKNOWN' for any `NULL'-complemented row built for the
operation.

Thus, for this outer join:

     T1 LEFT JOIN T2 ON T1.A=T2.A

Conditions such as these are null-rejected:

     T2.B IS NOT NULL,
     T2.B > 3,
     T2.C <= T1.C,
     T2.B < 2 OR T2.C > 1

Conditions such as these are not null-rejected:

     T2.B IS NULL,
     T1.B < 3 OR T2.B IS NOT NULL,
     T1.B < 3 OR T2.B > 3

The general rules for checking whether a condition is null-rejected for
an outer join operation are simple. A condition is null-rejected in the
following cases:

   * If it is of the form `A IS NOT NULL', where `A' is an attribute of
     any of the inner tables

   * If it is a predicate containing a reference to an inner table that
     evaluates to `UNKNOWN' when one of its arguments is `NULL'

   * If it is a conjunction containing a null-rejected condition as a
     conjunct

   * If it is a disjunction of null-rejected conditions

A condition can be null-rejected for one outer join operation in a
query and not null-rejected for another. In the query:

     SELECT * FROM T1 LEFT JOIN T2 ON T2.A=T1.A
                      LEFT JOIN T3 ON T3.B=T1.B
       WHERE T3.C > 0

the `WHERE' condition is null-rejected for the second outer join
operation but is not null-rejected for the first one.

If the `WHERE' condition is null-rejected for an outer join operation
in a query, the outer join operation is replaced by an inner join
operation.

For example, the preceding query is replaced with the query:

     SELECT * FROM T1 LEFT JOIN T2 ON T2.A=T1.A
                      INNER JOIN T3 ON T3.B=T1.B
       WHERE T3.C > 0

For the original query, the optimizer would evaluate plans compatible
with only one access order `T1,T2,T3'. For the replacing query, it
additionally considers the access sequence `T3,T1,T2'.

A conversion of one outer join operation may trigger a conversion of
another. Thus, the query:

     SELECT * FROM T1 LEFT JOIN T2 ON T2.A=T1.A
                      LEFT JOIN T3 ON T3.B=T2.B
       WHERE T3.C > 0

will be first converted to the query:

     SELECT * FROM T1 LEFT JOIN T2 ON T2.A=T1.A
                      INNER JOIN T3 ON T3.B=T2.B
       WHERE T3.C > 0

which is equivalent to the query:

     SELECT * FROM (T1 LEFT JOIN T2 ON T2.A=T1.A), T3
       WHERE T3.C > 0 AND T3.B=T2.B

Now the remaining outer join operation can be replaced by an inner
join, too, because the condition `T3.B=T2.B' is null-rejected and we
get a query without outer joins at all:

     SELECT * FROM (T1 INNER JOIN T2 ON T2.A=T1.A), T3
       WHERE T3.C > 0 AND T3.B=T2.B

Sometimes we succeed in replacing an embedded outer join operation, but
cannot convert the embedding outer join. The following query:

     SELECT * FROM T1 LEFT JOIN
                   (T2 LEFT JOIN T3 ON T3.B=T2.B)
                   ON T2.A=T1.A
       WHERE T3.C > 0

is converted to:

     SELECT * FROM T1 LEFT JOIN
                   (T2 INNER JOIN T3 ON T3.B=T2.B)
                   ON T2.A=T1.A
       WHERE T3.C > 0,

That can be rewritten only to the form still containing the embedding
outer join operation:

     SELECT * FROM T1 LEFT JOIN
                   (T2,T3)
                   ON (T2.A=T1.A AND T3.B=T2.B)
       WHERE T3.C > 0.

When trying to convert an embedded outer join operation in a query, we
must take into account the join condition for the embedding outer join
together with the `WHERE' condition. In the query:

     SELECT * FROM T1 LEFT JOIN
                   (T2 LEFT JOIN T3 ON T3.B=T2.B)
                   ON T2.A=T1.A AND T3.C=T1.C
       WHERE T3.D > 0 OR T1.D > 0

the `WHERE' condition is not null-rejected for the embedded outer join,
but the join condition of the embedding outer join `T2.A=T1.A AND
T3.C=T1.C' is null-rejected. So the query can be converted to:

     SELECT * FROM T1 LEFT JOIN
                   (T2, T3)
                   ON T2.A=T1.A AND T3.C=T1.C AND T3.B=T2.B
       WHERE T3.D > 0 OR T1.D > 0

The algorithm that converts outer join operations into inner joins was
implemented in full measure, as it has been described here, in MySQL
5.0.1. MySQL 4.1 performs only some simple conversions.


File: manual.info,  Node: order-by-optimization,  Next: group-by-optimization,  Prev: outer-join-simplification,  Up: select-optimization

8.3.1.16 `ORDER BY' Optimization
................................

In some cases, MySQL can use an index to satisfy an `ORDER BY' clause
without doing any extra sorting.

The index can also be used even if the `ORDER BY' does not match the
index exactly, as long as all of the unused portions of the index and
all the extra `ORDER BY' columns are constants in the `WHERE' clause.
The following queries use the index to resolve the `ORDER BY' part:

     SELECT * FROM t1
       ORDER BY KEY_PART1,KEY_PART2,... ;

     SELECT * FROM t1
       WHERE KEY_PART1=CONSTANT
       ORDER BY KEY_PART2;

     SELECT * FROM t1
       ORDER BY KEY_PART1 DESC, KEY_PART2 DESC;

     SELECT * FROM t1
       WHERE KEY_PART1=1
       ORDER BY KEY_PART1 DESC, KEY_PART2 DESC;

In some cases, MySQL _cannot_ use indexes to resolve the `ORDER BY',
although it still uses indexes to find the rows that match the `WHERE'
clause. These cases include the following:

   * You use `ORDER BY' on different keys:

          SELECT * FROM t1 ORDER BY KEY1, KEY2;

   * You use `ORDER BY' on nonconsecutive parts of a key:

          SELECT * FROM t1 WHERE KEY2=CONSTANT ORDER BY KEY_PART2;

   * You mix `ASC' and `DESC':

          SELECT * FROM t1 ORDER BY KEY_PART1 DESC, KEY_PART2 ASC;

   * The key used to fetch the rows is not the same as the one used in
     the `ORDER BY':

          SELECT * FROM t1 WHERE KEY2=CONSTANT ORDER BY KEY1;

   * You use `ORDER BY' with an expression that includes terms other
     than the key column name:

          SELECT * FROM t1 ORDER BY ABS(KEY);
          SELECT * FROM t1 ORDER BY -KEY;

   * You are joining many tables, and the columns in the `ORDER BY' are
     not all from the first nonconstant table that is used to retrieve
     rows. (This is the first table in the *Note `EXPLAIN': explain.
     output that does not have a `const' join type.)

   * You have different `ORDER BY' and `GROUP BY' expressions.

   * You index only a prefix of a column named in the `ORDER BY'
     clause. In this case, the index cannot be used to fully resolve
     the sort order. For example, if you have a *Note `CHAR(20)': char.
     column, but index only the first 10 bytes, the index cannot
     distinguish values past the 10th byte and a `filesort' will be
     needed.

   * The type of table index used does not store rows in order.  For
     example, this is true for a `HASH' index in a `MEMORY' table.

Availability of an index for sorting may be affected by the use of
column aliases. Suppose that the column `t1.a' is indexed. In this
statement, the name of the column in the select list is `a'.  It refers
to `t1.a', so for the reference to `a' in the `ORDER BY', the index can
be used:

     SELECT a FROM t1 ORDER BY a;

In this statement, the name of the column in the select list is also
`a', but it is the alias name. It refers to `ABS(a)', so for the
reference to `a' in the `ORDER BY', the index cannot be used:

     SELECT ABS(a) AS a FROM t1 ORDER BY a;

In the following statement, the `ORDER BY' refers to a name that is not
the name of a column in the select list. But there is a column in `t1'
named `a', so the `ORDER BY' uses that, and the index can be used. (The
resulting sort order may be completely different from the order for
`ABS(a)', of course.)

     SELECT ABS(a) AS b FROM t1 ORDER BY a;

By default, MySQL sorts all `GROUP BY COL1, COL2, ...' queries as if
you specified `ORDER BY COL1, COL2, ...' in the query as well. If you
include an `ORDER BY' clause explicitly that contains the same column
list, MySQL optimizes it away without any speed penalty, although the
sorting still occurs. If a query includes `GROUP BY' but you want to
avoid the overhead of sorting the result, you can suppress sorting by
specifying `ORDER BY NULL'. For example:

     INSERT INTO foo
     SELECT a, COUNT(*) FROM bar GROUP BY a ORDER BY NULL;

With *Note `EXPLAIN SELECT ... ORDER BY': explain, you can check
whether MySQL can use indexes to resolve the query. It cannot if you see
`Using filesort' in the `Extra' column. See *Note using-explain::.
Filesort uses a fixed-length row-storage format similar to that used by
the *Note `MEMORY': memory-storage-engine. storage engine.
Variable-length types such as *Note `VARCHAR': char. are stored using a
fixed length.

MySQL has two `filesort' algorithms for sorting and retrieving results.
The original method uses only the `ORDER BY' columns. The modified
method uses not just the `ORDER BY' columns, but all the columns used
in the query.

The optimizer selects which `filesort' algorithm to use. It normally
uses the modified algorithm except when *Note `BLOB': blob. or *Note
`TEXT': blob. columns are involved, in which case it uses the original
algorithm.

The original `filesort' algorithm works as follows:

  1. Read all rows according to key or by table scanning. Rows that do
     not match the `WHERE' clause are skipped.

  2. For each row, store a pair of values in a buffer (the sort key and
     the row pointer). The size of the buffer is the value of the
     `sort_buffer_size' system variable.

  3. When the buffer gets full, run a qsort (quicksort) on it and store
     the result in a temporary file. Save a pointer to the sorted
     block. (If all pairs fit into the sort buffer, no temporary file
     is created.)

  4. Repeat the preceding steps until all rows have been read.

  5. Do a multi-merge of up to `MERGEBUFF' (7) regions to one block in
     another temporary file. Repeat until all blocks from the first
     file are in the second file.

  6. Repeat the following until there are fewer than `MERGEBUFF2' (15)
     blocks left.

  7. On the last multi-merge, only the pointer to the row (the last
     part of the sort key) is written to a result file.

  8. Read the rows in sorted order by using the row pointers in the
     result file. To optimize this, we read in a big block of row
     pointers, sort them, and use them to read the rows in sorted order
     into a row buffer. The size of the buffer is the value of the
     `read_rnd_buffer_size' system variable. The code for this step is
     in the `sql/records.cc' source file.

One problem with this approach is that it reads rows twice: One time
when evaluating the `WHERE' clause, and again after sorting the pair
values. And even if the rows were accessed successively the first time
(for example, if a table scan is done), the second time they are
accessed randomly. (The sort keys are ordered, but the row positions
are not.)

The modified `filesort' algorithm incorporates an optimization such
that it records not only the sort key value and row position, but also
the columns required for the query. This avoids reading the rows twice.
The modified `filesort' algorithm works like this:

  1. Read the rows that match the `WHERE' clause.

  2. For each row, record a tuple of values consisting of the sort key
     value and row position, and also the columns required for the
     query.

  3. Sort the tuples by sort key value

  4. Retrieve the rows in sorted order, but read the required columns
     directly from the sorted tuples rather than by accessing the table
     a second time.

Using the modified `filesort' algorithm, the tuples are longer than the
pairs used in the original method, and fewer of them fit in the sort
buffer (the size of which is given by `sort_buffer_size').  As a
result, it is possible for the extra I/O to make the modified approach
slower, not faster. To avoid a slowdown, the optimization is used only
if the total size of the extra columns in the sort tuple does not
exceed the value of the `max_length_for_sort_data' system variable. (A
symptom of setting the value of this variable too high is that you
should see high disk activity and low CPU activity.)

For slow queries for which `filesort' is not used, you might try
lowering `max_length_for_sort_data' to a value that is appropriate to
trigger a `filesort'.

If you want to increase `ORDER BY' speed, check whether you can get
MySQL to use indexes rather than an extra sorting phase. If this is not
possible, you can try the following strategies:

   * Increase the size of the `sort_buffer_size' variable.

   * Increase the size of the `read_rnd_buffer_size' variable.

   * Use less RAM per row by declaring columns only as large as they
     need to be to hold the values stored in them. For example,
     `CHAR(16)' is better than `CHAR(200)' if values never exceed 16
     characters.

   * Change `tmpdir' to point to a dedicated file system with large
     amounts of free space.  Also, this option accepts several paths
     that are used in round-robin fashion, so you can use this feature
     to spread the load across several directories. Paths should be
     separated by colon characters (``:'') on Unix and semicolon
     characters (``;'') on Windows, NetWare, and OS/2. The paths should
     be for directories in file systems that are located on different
     _physical_ disks, not different partitions on the same disk.


File: manual.info,  Node: group-by-optimization,  Next: distinct-optimization,  Prev: order-by-optimization,  Up: select-optimization

8.3.1.17 `GROUP BY' Optimization
................................

* Menu:

* loose-index-scan::             Loose Index Scan
* tight-index-scan::             Tight Index Scan

The most general way to satisfy a `GROUP BY' clause is to scan the
whole table and create a new temporary table where all rows from each
group are consecutive, and then use this temporary table to discover
groups and apply aggregate functions (if any). In some cases, MySQL is
able to do much better than that and to avoid creation of temporary
tables by using index access.

The most important preconditions for using indexes for `GROUP BY' are
that all `GROUP BY' columns reference attributes from the same index,
and that the index stores its keys in order (for example, this is a
`BTREE' index and not a `HASH' index). Whether use of temporary tables
can be replaced by index access also depends on which parts of an index
are used in a query, the conditions specified for these parts, and the
selected aggregate functions.

There are two ways to execute a `GROUP BY' query through index access,
as detailed in the following sections. In the first method, the
grouping operation is applied together with all range predicates (if
any). The second method first performs a range scan, and then groups the
resulting tuples.

In MySQL, `GROUP BY' is used for sorting, so the server may also apply
`ORDER BY' optimizations to grouping. See *Note order-by-optimization::.


File: manual.info,  Node: loose-index-scan,  Next: tight-index-scan,  Prev: group-by-optimization,  Up: group-by-optimization

8.3.1.18 Loose Index Scan
.........................

The most efficient way to process `GROUP BY' is when an index is used
to directly retrieve the grouping columns. With this access method,
MySQL uses the property of some index types that the keys are ordered
(for example, `BTREE'). This property enables use of lookup groups in
an index without having to consider all keys in the index that satisfy
all `WHERE' conditions. This access method considers only a fraction of
the keys in an index, so it is called a _loose index scan_. When there
is no `WHERE' clause, a loose index scan reads as many keys as the
number of groups, which may be a much smaller number than that of all
keys. If the `WHERE' clause contains range predicates (see the
discussion of the `range' join type in *Note using-explain::), a loose
index scan looks up the first key of each group that satisfies the range
conditions, and again reads the least possible number of keys. This is
possible under the following conditions:

   * The query is over a single table.

   * The `GROUP BY' names only columns that form a leftmost prefix of
     the index and no other columns. (If, instead of `GROUP BY', the
     query has a `DISTINCT' clause, all distinct attributes refer to
     columns that form a leftmost prefix of the index.) For example, if
     a table `t1' has an index on `(c1,c2,c3)', loose index scan is
     applicable if the query has `GROUP BY c1, c2,'. It is not
     applicable if the query has `GROUP BY c2, c3' (the columns are not
     a leftmost prefix) or `GROUP BY c1, c2, c4' (`c4' is not in the
     index).

   * The only aggregate functions used in the select list (if any) are
     `MIN()' and `MAX()', and all of them refer to the same column. The
     column must be in the index and must follow the columns in the
     `GROUP BY'.

   * Any other parts of the index than those from the `GROUP BY'
     referenced in the query must be constants (that is, they must be
     referenced in equalities with constants), except for the argument
     of `MIN()' or `MAX()' functions.

   * For columns in the index, full column values must be indexed, not
     just a prefix. For example, with `c1 VARCHAR(20), INDEX (c1(10))',
     the index cannot be used for loose index scan.

If loose index scan is applicable to a query, the *Note `EXPLAIN':
explain. output shows `Using index for group-by' in the `Extra' column.

Assume that there is an index `idx(c1,c2,c3)' on table
`t1(c1,c2,c3,c4)'. The loose index scan access method can be used for
the following queries:

     SELECT c1, c2 FROM t1 GROUP BY c1, c2;
     SELECT DISTINCT c1, c2 FROM t1;
     SELECT c1, MIN(c2) FROM t1 GROUP BY c1;
     SELECT c1, c2 FROM t1 WHERE c1 < CONST GROUP BY c1, c2;
     SELECT MAX(c3), MIN(c3), c1, c2 FROM t1 WHERE c2 > CONST GROUP BY c1, c2;
     SELECT c2 FROM t1 WHERE c1 < CONST GROUP BY c1, c2;
     SELECT c1, c2 FROM t1 WHERE c3 = CONST GROUP BY c1, c2;

The following queries cannot be executed with this quick select method,
for the reasons given:

   * There are aggregate functions other than `MIN()' or `MAX()':

          SELECT c1, SUM(c2) FROM t1 GROUP BY c1;

   * The columns in the `GROUP BY' clause do not form a leftmost prefix
     of the index:

          SELECT c1, c2 FROM t1 GROUP BY c2, c3;

   * The query refers to a part of a key that comes after the `GROUP
     BY' part, and for which there is no equality with a constant:

          SELECT c1, c3 FROM t1 GROUP BY c1, c2;

     Were the query to include `WHERE c3 = CONST', loose index scan
     could be used.


File: manual.info,  Node: tight-index-scan,  Prev: loose-index-scan,  Up: group-by-optimization

8.3.1.19 Tight Index Scan
.........................

A tight index scan may be either a full index scan or a range index
scan, depending on the query conditions.

When the conditions for a loose index scan are not met, it still may be
possible to avoid creation of temporary tables for `GROUP BY' queries.
If there are range conditions in the `WHERE' clause, this method reads
only the keys that satisfy these conditions.  Otherwise, it performs an
index scan. Because this method reads all keys in each range defined by
the `WHERE' clause, or scans the whole index if there are no range
conditions, we term it a _tight index scan_. With a tight index scan,
the grouping operation is performed only after all keys that satisfy
the range conditions have been found.

For this method to work, it is sufficient that there is a constant
equality condition for all columns in a query referring to parts of the
key coming before or in between parts of the `GROUP BY' key. The
constants from the equality conditions fill in any `gaps' in the search
keys so that it is possible to form complete prefixes of the index.
These index prefixes then can be used for index lookups. If we require
sorting of the `GROUP BY' result, and it is possible to form search
keys that are prefixes of the index, MySQL also avoids extra sorting
operations because searching with prefixes in an ordered index already
retrieves all the keys in order.

Assume that there is an index `idx(c1,c2,c3)' on table
`t1(c1,c2,c3,c4)'. The following queries do not work with the loose
index scan access method described earlier, but still work with the
tight index scan access method.

   * There is a gap in the `GROUP BY', but it is covered by the
     condition `c2 = 'a'':

          SELECT c1, c2, c3 FROM t1 WHERE c2 = 'a' GROUP BY c1, c3;

   * The `GROUP BY' does not begin with the first part of the key, but
     there is a condition that provides a constant for that part:

          SELECT c1, c2, c3 FROM t1 WHERE c1 = 'a' GROUP BY c2, c3;


File: manual.info,  Node: distinct-optimization,  Next: in-subquery-optimization,  Prev: group-by-optimization,  Up: select-optimization

8.3.1.20 `DISTINCT' Optimization
................................

`DISTINCT' combined with `ORDER BY' needs a temporary table in many
cases.

Because `DISTINCT' may use `GROUP BY', you should be aware of how MySQL
works with columns in `ORDER BY' or `HAVING' clauses that are not part
of the selected columns. See *Note group-by-hidden-columns::.

In most cases, a `DISTINCT' clause can be considered as a special case
of `GROUP BY'.  For example, the following two queries are equivalent:

     SELECT DISTINCT c1, c2, c3 FROM t1
     WHERE c1 > CONST;

     SELECT c1, c2, c3 FROM t1
     WHERE c1 > CONST GROUP BY c1, c2, c3;

Due to this equivalence, the optimizations applicable to `GROUP BY'
queries can be also applied to queries with a `DISTINCT' clause. Thus,
for more details on the optimization possibilities for `DISTINCT'
queries, see *Note group-by-optimization::.

When combining `LIMIT ROW_COUNT' with `DISTINCT', MySQL stops as soon
as it finds ROW_COUNT unique rows.

If you do not use columns from all tables named in a query, MySQL stops
scanning any unused tables as soon as it finds the first match. In the
following case, assuming that `t1' is used before `t2' (which you can
check with *Note `EXPLAIN': explain.), MySQL stops reading from `t2'
(for any particular row in `t1') when it finds the first row in `t2':

     SELECT DISTINCT t1.a FROM t1, t2 where t1.a=t2.a;


File: manual.info,  Node: in-subquery-optimization,  Next: limit-optimization,  Prev: distinct-optimization,  Up: select-optimization

8.3.1.21 Optimizing `IN'/`=ANY' Subqueries
..........................................

Certain optimizations are applicable to comparisons that use the `IN'
operator to test subquery results (or that use `=ANY', which is
equivalent).  This section discusses these optimizations, particularly
with regard to the challenges that `NULL' values present. Suggestions
on what you can do to help the optimizer are given at the end of the
discussion.

Consider the following subquery comparison:

     OUTER_EXPR IN (SELECT INNER_EXPR FROM ... WHERE SUBQUERY_WHERE)

MySQL evaluates queries `from outside to inside.' That is, it first
obtains the value of the outer expression OUTER_EXPR, and then runs the
subquery and captures the rows that it produces.

A very useful optimization is to `inform' the subquery that the only
rows of interest are those where the inner expression INNER_EXPR is
equal to OUTER_EXPR. This is done by pushing down an appropriate
equality into the subquery's `WHERE' clause. That is, the comparison is
converted to this:

     EXISTS (SELECT 1 FROM ... WHERE SUBQUERY_WHERE AND OUTER_EXPR=INNER_EXPR)

After the conversion, MySQL can use the pushed-down equality to limit
the number of rows that it must examine when evaluating the subquery.

More generally, a comparison of N values to a subquery that returns
N-value rows is subject to the same conversion. If OE_I and IE_I
represent corresponding outer and inner expression values, this
subquery comparison:

     (OE_1, ..., OE_N) IN
       (SELECT IE_1, ..., IE_N FROM ... WHERE SUBQUERY_WHERE)

Becomes:

     EXISTS (SELECT 1 FROM ... WHERE SUBQUERY_WHERE
                               AND OE_1 = IE_1
                               AND ...
                               AND OE_N = IE_N)

The following discussion assumes a single pair of outer and inner
expression values for simplicity.

The conversion just described has its limitations. It is valid only if
we ignore possible `NULL' values.  That is, the `pushdown' strategy
works as long as both of these two conditions are true:

   * OUTER_EXPR and INNER_EXPR cannot be `NULL'.

   * You do not need to distinguish `NULL' from `FALSE' subquery
     results. (If the subquery is a part of an `OR' or `AND' expression
     in the `WHERE' clause, MySQL assumes that you don't care.)

When either or both of those conditions do not hold, optimization is
more complex.

Suppose that OUTER_EXPR is known to be a non-`NULL' value but the
subquery does not produce a row such that OUTER_EXPR = INNER_EXPR. Then
`OUTER_EXPR IN (SELECT ...)' evaluates as follows:

   * `NULL', if the *Note `SELECT': select. produces any row where
     INNER_EXPR is `NULL'

   * `FALSE', if the *Note `SELECT': select. produces only non-`NULL'
     values or produces nothing

In this situation, the approach of looking for rows with `OUTER_EXPR =
INNER_EXPR' is no longer valid. It is necessary to look for such rows,
but if none are found, also look for rows where INNER_EXPR is `NULL'.
Roughly speaking, the subquery can be converted to:

     EXISTS (SELECT 1 FROM ... WHERE SUBQUERY_WHERE AND
             (OUTER_EXPR=INNER_EXPR OR INNER_EXPR IS NULL))

The need to evaluate the extra `IS NULL' condition is why MySQL has the
`ref_or_null' access method:

     mysql> EXPLAIN
         -> SELECT OUTER_EXPR IN (SELECT t2.maybe_null_key
         ->                       FROM t2, t3 WHERE ...)
         -> FROM t1;
     *************************** 1. row ***************************
                id: 1
       select_type: PRIMARY
             table: t1
     ...
     *************************** 2. row ***************************
                id: 2
       select_type: DEPENDENT SUBQUERY
             table: t2
              type: ref_or_null
     possible_keys: maybe_null_key
               key: maybe_null_key
           key_len: 5
               ref: func
              rows: 2
             Extra: Using where; Using index
     ...

The `unique_subquery' and `index_subquery' subqery-specific access
methods also have or-null variants.  However, they are not visible in
*Note `EXPLAIN': explain. output, so you must use *Note `EXPLAIN
EXTENDED': explain. followed by *Note `SHOW WARNINGS': show-warnings.
(note the `checking NULL' in the warning message):

     mysql> EXPLAIN EXTENDED
         -> SELECT OUTER_EXPR IN (SELECT maybe_null_key FROM t2) FROM t1\G
     *************************** 1. row ***************************
                id: 1
       select_type: PRIMARY
             table: t1
     ...
     *************************** 2. row ***************************
                id: 2
       select_type: DEPENDENT SUBQUERY
             table: t2
              type: index_subquery
     possible_keys: maybe_null_key
               key: maybe_null_key
           key_len: 5
               ref: func
              rows: 2
             Extra: Using index

     mysql> SHOW WARNINGS\G
     *************************** 1. row ***************************
       Level: Note
        Code: 1003
     Message: select (`test`.`t1`.`outer_expr`,
              (((`test`.`t1`.`outer_expr`) in t2 on
              maybe_null_key checking NULL))) AS `outer_expr IN (SELECT
              maybe_null_key FROM t2)` from `test`.`t1`

The additional `OR ... IS NULL' condition makes query execution
slightly more complicated (and some optimizations within the subquery
become inapplicable), but generally this is tolerable.

The situation is much worse when OUTER_EXPR can be `NULL'. According to
the SQL interpretation of `NULL' as `unknown value,' `NULL IN (SELECT
INNER_EXPR ...)' should evaluate to:

   * `NULL', if the *Note `SELECT': select. produces any rows

   * `FALSE', if the *Note `SELECT': select. produces no rows

For proper evaluation, it is necessary to be able to check whether the
*Note `SELECT': select. has produced any rows at all, so `OUTER_EXPR =
INNER_EXPR' cannot be pushed down into the subquery. This is a problem,
because many real world subqueries become very slow unless the equality
can be pushed down.

Essentially, there must be different ways to execute the subquery
depending on the value of OUTER_EXPR. In MySQL 5.0 before 5.0.36, the
optimizer chose speed over distinguishing a `NULL' from `FALSE' result,
so for some queries, you might get a `FALSE' result rather than `NULL'.

As of MySQL 5.0.36, the optimizer chooses SQL compliance over speed, so
it accounts for the possibility that OUTER_EXPR might be `NULL'.

If OUTER_EXPR is `NULL', to evaluate the following expression, it is
necessary to run the *Note `SELECT': select. to determine whether it
produces any rows:

     NULL IN (SELECT INNER_EXPR FROM ... WHERE SUBQUERY_WHERE)

It is necessary to run the original *Note `SELECT': select. here,
without any pushed-down equalities of the kind mentioned earlier.

On the other hand, when OUTER_EXPR is not `NULL', it is absolutely
essential that this comparison:

     OUTER_EXPR IN (SELECT INNER_EXPR FROM ... WHERE SUBQUERY_WHERE)

be converted to this expression that uses a pushed-down condition:

     EXISTS (SELECT 1 FROM ... WHERE SUBQUERY_WHERE AND OUTER_EXPR=INNER_EXPR)

Without this conversion, subqueries will be slow. To solve the dilemma
of whether to push down or not push down conditions into the subquery,
the conditions are wrapped in `trigger' functions. Thus, an expression
of the following form:

     OUTER_EXPR IN (SELECT INNER_EXPR FROM ... WHERE SUBQUERY_WHERE)

is converted into:

     EXISTS (SELECT 1 FROM ... WHERE SUBQUERY_WHERE
                               AND trigcond(OUTER_EXPR=INNER_EXPR))

More generally, if the subquery comparison is based on several pairs of
outer and inner expressions, the conversion takes this comparison:

     (OE_1, ..., OE_N) IN (SELECT IE_1, ..., IE_N FROM ... WHERE SUBQUERY_WHERE)

and converts it to this expression:

     EXISTS (SELECT 1 FROM ... WHERE SUBQUERY_WHERE
                               AND trigcond(OE_1=IE_1)
                               AND ...
                               AND trigcond(OE_N=IE_N)
            )

Each `trigcond(X)' is a special function that evaluates to the
following values:

   * X when the `linked' outer expression OE_I is not `NULL'

   * `TRUE' when the `linked' outer expression OE_I is `NULL'

Note that trigger functions are _not_ triggers of the kind that you
create with *Note `CREATE TRIGGER': create-trigger.

Equalities that are wrapped into `trigcond()' functions are not first
class predicates for the query optimizer. Most optimizations cannot
deal with predicates that may be turned on and off at query execution
time, so they assume any `trigcond(X)' to be an unknown function and
ignore it. At the moment, triggered equalities can be used by those
optimizations:

   * Reference optimizations: `trigcond(X=Y [OR Y IS NULL])' can be
     used to construct `ref', `eq_ref', or `ref_or_null' table accesses.

   * Index lookup-based subquery execution engines: `trigcond(X=Y)' can
     be used to construct `unique_subquery' or `index_subquery'
     accesses.

   * Table-condition generator: If the subquery is a join of several
     tables, the triggered condition will be checked as soon as
     possible.

When the optimizer uses a triggered condition to create some kind of
index lookup-based access (as for the first two items of the preceding
list), it must have a fallback strategy for the case when the condition
is turned off. This fallback strategy is always the same: Do a full
table scan. In *Note `EXPLAIN': explain. output, the fallback shows up
as `Full scan on NULL key' in the `Extra' column:

     mysql> EXPLAIN SELECT t1.col1,
         -> t1.col1 IN (SELECT t2.key1 FROM t2 WHERE t2.col2=t1.col2) FROM t1\G
     *************************** 1. row ***************************
                id: 1
       select_type: PRIMARY
             table: t1
             ...
     *************************** 2. row ***************************
                id: 2
       select_type: DEPENDENT SUBQUERY
             table: t2
              type: index_subquery
     possible_keys: key1
               key: key1
           key_len: 5
               ref: func
              rows: 2
             Extra: Using where; Full scan on NULL key

If you run *Note `EXPLAIN EXTENDED': explain. followed by *Note `SHOW
WARNINGS': show-warnings, you can see the triggered condition:

     *************************** 1. row ***************************
       Level: Note
        Code: 1003
     Message: select `test`.`t1`.`col1` AS `col1`,
              <in_optimizer>(`test`.`t1`.`col1`,
              <exists>(<index_lookup>(<cache>(`test`.`t1`.`col1`) in t2
              on key1 checking NULL
              where (`test`.`t2`.`col2` = `test`.`t1`.`col2`) having
              trigcond(<is_not_null_test>(`test`.`t2`.`key1`))))) AS
              `t1.col1 IN (select t2.key1 from t2 where t2.col2=t1.col2)`
              from `test`.`t1`

The use of triggered conditions has some performance implications. A
`NULL IN (SELECT ...)' expression now may cause a full table scan
(which is slow) when it previously did not. This is the price paid for
correct results (the goal of the trigger-condition strategy was to
improve compliance and not speed).

For multiple-table subqueries, execution of `NULL IN (SELECT ...)' will
be particularly slow because the join optimizer doesn't optimize for
the case where the outer expression is `NULL'. It assumes that subquery
evaluations with `NULL' on the left side are very rare, even if there
are statistics that indicate otherwise. On the other hand, if the outer
expression might be `NULL' but never actually is, there is no
performance penalty.

To help the query optimizer better execute your queries, use these tips:

   * A column must be declared as `NOT NULL' if it really is. (This
     also helps other aspects of the optimizer.)

   * If you don't need to distinguish a `NULL' from `FALSE' subquery
     result, you can easily avoid the slow execution path. Replace a
     comparison that looks like this:

          OUTER_EXPR IN (SELECT INNER_EXPR FROM ...)

     with this expression:

          (OUTER_EXPR IS NOT NULL) AND (OUTER_EXPR IN (SELECT INNER_EXPR FROM ...))

     Then `NULL IN (SELECT ...)' will never be evaluated because MySQL
     stops evaluating `AND' parts as soon as the expression result is
     clear.


File: manual.info,  Node: limit-optimization,  Next: how-to-avoid-table-scan,  Prev: in-subquery-optimization,  Up: select-optimization

8.3.1.22 `LIMIT' Optimization
.............................

In some cases, MySQL handles a query differently when you are using
`LIMIT ROW_COUNT' and not using `HAVING':

   * If you are selecting only a few rows with `LIMIT', MySQL uses
     indexes in some cases when normally it would prefer to do a full
     table scan.

   * If you use `LIMIT ROW_COUNT' with `ORDER BY', MySQL ends the
     sorting as soon as it has found the first ROW_COUNT rows of the
     sorted result, rather than sorting the entire result. If ordering
     is done by using an index, this is very fast. If a filesort must
     be done, all rows that match the query without the `LIMIT' clause
     must be selected, and most or all of them must be sorted, before
     it can be ascertained that the first ROW_COUNT rows have been
     found.  In either case, after the initial rows have been found,
     there is no need to sort any remainder of the result set, and
     MySQL does not do so.

   * When combining `LIMIT ROW_COUNT' with `DISTINCT', MySQL stops as
     soon as it finds ROW_COUNT unique rows.

   * In some cases, a `GROUP BY' can be resolved by reading the key in
     order (or doing a sort on the key) and then calculating summaries
     until the key value changes. In this case, `LIMIT ROW_COUNT' does
     not calculate any unnecessary `GROUP BY' values.

   * As soon as MySQL has sent the required number of rows to the
     client, it aborts the query unless you are using
     `SQL_CALC_FOUND_ROWS'.

   * `LIMIT 0' quickly returns an empty set.  This can be useful for
     checking the validity of a query.  When using one of the MySQL
     APIs, it can also be employed for obtaining the types of the
     result columns. (This trick does not work in the MySQL Monitor (the
     *Note `mysql': mysql. program), which merely displays `Empty set'
     in such cases; you should instead use *Note `SHOW COLUMNS':
     show-columns. or *Note `DESCRIBE': describe. for this purpose.)

   * When the server uses temporary tables to resolve the query, it
     uses the `LIMIT ROW_COUNT' clause to calculate how much space is
     required.


File: manual.info,  Node: how-to-avoid-table-scan,  Prev: limit-optimization,  Up: select-optimization

8.3.1.23 How to Avoid Table Scans
.................................

The output from *Note `EXPLAIN': explain. shows `ALL' in the `type'
column when MySQL uses a table scan to resolve a query. This usually
happens under the following conditions:

   * The table is so small that it is faster to perform a table scan
     than to bother with a key lookup. This is common for tables with
     fewer than 10 rows and a short row length.

   * There are no usable restrictions in the `ON' or `WHERE' clause for
     indexed columns.

   * You are comparing indexed columns with constant values and MySQL
     has calculated (based on the index tree) that the constants cover
     too large a part of the table and that a table scan would be
     faster. See *Note where-optimizations::.

   * You are using a key with low cardinality (many rows match the key
     value) through another column. In this case, MySQL assumes that by
     using the key it probably will do many key lookups and that a
     table scan would be faster.

For small tables, a table scan often is appropriate and the performance
impact is negligible. For large tables, try the following techniques to
avoid having the optimizer incorrectly choose a table scan:

   * Use `ANALYZE TABLE TBL_NAME' to update the key distributions for
     the scanned table. See *Note analyze-table::.

   * Use `FORCE INDEX' for the scanned table to tell MySQL that table
     scans are very expensive compared to using the given index:

          SELECT * FROM t1, t2 FORCE INDEX (INDEX_FOR_COLUMN)
            WHERE t1.COL_NAME=t2.COL_NAME;

     See *Note index-hints::.

   * Start *Note `mysqld': mysqld. with the `--max-seeks-for-key=1000'
     option or use `SET max_seeks_for_key=1000' to tell the optimizer to
     assume that no key scan causes more than 1,000 key seeks.  See
     *Note server-system-variables::.


File: manual.info,  Node: non-select-optimization,  Next: miscellaneous-optimization-tips,  Prev: select-optimization,  Up: statement-optimization

8.3.2 Optimizing Non-`SELECT' Statements
----------------------------------------

* Menu:

* insert-speed::                 Speed of `INSERT' Statements
* update-speed::                 Speed of `UPDATE' Statements
* delete-speed::                 Speed of `DELETE' Statements
* repair-table-speed::           Speed of `REPAIR TABLE' Statements


File: manual.info,  Node: insert-speed,  Next: update-speed,  Prev: non-select-optimization,  Up: non-select-optimization

8.3.2.1 Speed of `INSERT' Statements
....................................

The time required for inserting a row is determined by the following
factors, where the numbers indicate approximate proportions:

   * Connecting: (3)

   * Sending query to server: (2)

   * Parsing query: (2)

   * Inserting row: (1 x size of row)

   * Inserting indexes: (1 x number of indexes)

   * Closing: (1)

This does not take into consideration the initial overhead to open
tables, which is done once for each concurrently running query.

The size of the table slows down the insertion of indexes by log N,
assuming B-tree indexes.

You can use the following methods to speed up inserts:

   * If you are inserting many rows from the same client at the same
     time, use *Note `INSERT': insert.  statements with multiple
     `VALUES' lists to insert several rows at a time. This is
     considerably faster (many times faster in some cases) than using
     separate single-row *Note `INSERT': insert.  statements. If you
     are adding data to a nonempty table, you can tune the
     `bulk_insert_buffer_size' variable to make data insertion even
     faster. See *Note server-system-variables::.

   * If multiple clients are inserting a lot of rows, you can get
     higher speed by using the *Note `INSERT DELAYED': insert-delayed.
     statement. See *Note insert-delayed::.

   * For a `MyISAM' table, you can use concurrent inserts to add rows
     at the same time that *Note `SELECT': select. statements are
     running, if there are no deleted rows in middle of the data file.
     See *Note concurrent-inserts::.

   * When loading a table from a text file, use *Note `LOAD DATA
     INFILE': load-data. This is usually 20 times faster than using
     *Note `INSERT': insert. statements.  See *Note load-data::.

   * With some extra work, it is possible to make *Note `LOAD DATA
     INFILE': load-data. run even faster for a `MyISAM' table when the
     table has many indexes. Use the following procedure:

       1. Optionally create the table with *Note `CREATE TABLE':
          create-table.

       2. Execute a *Note `FLUSH TABLES': flush. statement or a *Note
          `mysqladmin flush-tables': mysqladmin. command.

       3. Use *Note `myisamchk --keys-used=0 -rq
          /PATH/TO/DB/TBL_NAME.': myisamchk.  This removes all use of
          indexes for the table.

       4. Insert data into the table with *Note `LOAD DATA INFILE':
          load-data. This does not update any indexes and therefore is
          very fast.

       5. If you intend only to read from the table in the future, use
          *Note `myisampack': myisampack. to compress it. See *Note
          compressed-format::.

       6. Re-create the indexes with *Note `myisamchk -rq
          /PATH/TO/DB/TBL_NAME': myisamchk.  This creates the index
          tree in memory before writing it to disk, which is much
          faster that updating the index during *Note `LOAD DATA
          INFILE': load-data. because it avoids lots of disk seeks.
          The resulting index tree is also perfectly balanced.

       7. Execute a *Note `FLUSH TABLES': flush. statement or a *Note
          `mysqladmin flush-tables': mysqladmin. command.

     *Note `LOAD DATA INFILE': load-data. performs the preceding
     optimization automatically if the `MyISAM' table into which you
     insert data is empty. The main difference between automatic
     optimization and using the procedure explicitly is that you can let
     *Note `myisamchk': myisamchk. allocate much more temporary memory
     for the index creation than you might want the server to allocate
     for index re-creation when it executes the *Note `LOAD DATA
     INFILE': load-data. statement.

     You can also disable or enable the nonunique indexes for a
     `MyISAM' table by using the following statements rather than *Note
     `myisamchk': myisamchk. If you use these statements, you can skip
     the *Note `FLUSH TABLE': flush. operations:

          ALTER TABLE TBL_NAME DISABLE KEYS;
          ALTER TABLE TBL_NAME ENABLE KEYS;

   * To speed up *Note `INSERT': insert.  operations that are performed
     with multiple statements for nontransactional tables, lock your
     tables:

          LOCK TABLES a WRITE;
          INSERT INTO a VALUES (1,23),(2,34),(4,33);
          INSERT INTO a VALUES (8,26),(6,29);
          ...
          UNLOCK TABLES;

     This benefits performance because the index buffer is flushed to
     disk only once, after all *Note `INSERT': insert. statements have
     completed. Normally, there would be as many index buffer flushes
     as there are *Note `INSERT': insert.  statements. Explicit locking
     statements are not needed if you can insert all rows with a single
     *Note `INSERT': insert.

     To obtain faster insertions for transactional tables, you should
     use *Note `START TRANSACTION': commit. and *Note `COMMIT': commit.
     instead of *Note `LOCK TABLES': lock-tables.

     Locking also lowers the total time for multiple-connection tests,
     although the maximum wait time for individual connections might go
     up because they wait for locks.  Suppose that five clients attempt
     to perform inserts simultaneously as follows:

        * Connection 1 does 1000 inserts

        * Connections 2, 3, and 4 do 1 insert

        * Connection 5 does 1000 inserts

     If you do not use locking, connections 2, 3, and 4 finish before 1
     and 5. If you use locking, connections 2, 3, and 4 probably do not
     finish before 1 or 5, but the total time should be about 40%
     faster.

     *Note `INSERT': insert, *Note `UPDATE': update, and *Note
     `DELETE': delete. operations are very fast in MySQL, but you can
     obtain better overall performance by adding locks around
     everything that does more than about five successive inserts or
     updates. If you do very many successive inserts, you could do a
     *Note `LOCK TABLES': lock-tables. followed by an *Note `UNLOCK
     TABLES': lock-tables. once in a while (each 1,000 rows or so) to
     permit other threads to access the table. This would still result
     in a nice performance gain.

     *Note `INSERT': insert. is still much slower for loading data than
     *Note `LOAD DATA INFILE': load-data, even when using the
     strategies just outlined.

   * To increase performance for `MyISAM' tables, for both *Note `LOAD
     DATA INFILE': load-data. and *Note `INSERT': insert, enlarge the
     key cache by increasing the `key_buffer_size' system variable. See
     *Note server-parameters::.


File: manual.info,  Node: update-speed,  Next: delete-speed,  Prev: insert-speed,  Up: non-select-optimization

8.3.2.2 Speed of `UPDATE' Statements
....................................

An update statement is optimized like a *Note `SELECT': select. query
with the additional overhead of a write. The speed of the write depends
on the amount of data being updated and the number of indexes that are
updated. Indexes that are not changed do not get updated.

Another way to get fast updates is to delay updates and then do many
updates in a row later. Performing multiple updates together is much
quicker than doing one at a time if you lock the table.

For a `MyISAM' table that uses dynamic row format, updating a row to a
longer total length may split the row. If you do this often, it is very
important to use *Note `OPTIMIZE TABLE': optimize-table. occasionally.
See *Note optimize-table::.


File: manual.info,  Node: delete-speed,  Next: repair-table-speed,  Prev: update-speed,  Up: non-select-optimization

8.3.2.3 Speed of `DELETE' Statements
....................................

The time required to delete individual rows is exactly proportional to
the number of indexes. To delete rows more quickly, you can increase
the size of the key cache by increasing the `key_buffer_size' system
variable. See *Note server-parameters::.

To delete all rows from a table, `TRUNCATE TABLE TBL_NAME' is faster
than than `DELETE FROM TBL_NAME'. Truncate operations are not
transaction-safe; an error occurs when attempting one in the course of
an active transaction or active table lock. See *Note truncate-table::.


File: manual.info,  Node: repair-table-speed,  Prev: delete-speed,  Up: non-select-optimization

8.3.2.4 Speed of `REPAIR TABLE' Statements
..........................................

*Note `REPAIR TABLE': repair-table. for `MyISAM' tables is similar to
using *Note `myisamchk': myisamchk. for repair operations, and some of
the same performance optimizations apply:

   * *Note `myisamchk': myisamchk. has variables that control memory
     allocation. You may be able to its improve performance by setting
     these variables, as described in *Note myisamchk-memory::.

   * For *Note `REPAIR TABLE': repair-table, the same principle
     applies, but because the repair is done by the server, you set
     server system variables instead of *Note `myisamchk': myisamchk.
     variables. Also, In addition to setting memory-allocation
     variables, increasing the `myisam_max_sort_file_size' system
     variable increases the likelihood that the repair will use the
     faster filesort method and avoid the slower repair by key cache
     method. Set the variable to the maximum file size for your system,
     after checking to be sure that there is enough free space to hold
     a copy of the table files. The free space must be available in the
     file system containing the original table files.

Suppose that a *Note `myisamchk': myisamchk. table-repair operation is
done using the following options to set its memory-allocation variables:

     --key_buffer_size=128M --sort_buffer_size=256M
     --read_buffer_size=64M --write_buffer_size=64M

Some of those *Note `myisamchk': myisamchk. variables correspond to
server system variables:

*Note `myisamchk': myisamchk.        System Variable
Variable                             
`key_buffer_size'                    `key_buffer_size'
`sort_buffer_size'                   `myisam_sort_buffer_size'
`read_buffer_size'                   `read_buffer_size'
`write_buffer_size'                  none

Each of the server system variables can be set at runtime, and some of
them (`myisam_sort_buffer_size', `read_buffer_size') have a session
value in addition to a global value. Setting a session value limits the
effect of the change to your current session and does not affect other
users. Changing a global-only variable (`key_buffer_size',
`myisam_max_sort_file_size') affects other users as well. For
`key_buffer_size', you must take into account that the buffer is shared
with those users.  For example, if you set the *Note `myisamchk':
myisamchk.  `key_buffer_size' variable to 128MB, you could set the
corresponding `key_buffer_size' system variable larger than that (if it
is not already set larger), to allow for key buffer use by activity in
other sessions.  However, changing the global key buffer size
invalidates the buffer, causing increased disk I/O and slowdown for
other sessions. An alternative that avoids this problem is to use a
separate key cache, assign to it the indexes from the table to be
repaired, and deallocate it when the repair is complete.  See *Note
multiple-key-caches::.

Based on the preceding remarks, a *Note `REPAIR TABLE': repair-table.
operation can be done as follows to use settings similar to the *Note
`myisamchk': myisamchk. command.  Here a separate 128MB key buffer is
allocated and the file system is assumed to permit a file size of at
least 100GB.

     SET SESSION myisam_sort_buffer_size = 256*1024*1024;
     SET SESSION read_buffer_size = 64*1024*1024;
     SET GLOBAL myisam_max_sort_file_size = 100*1024*1024*1024;
     SET GLOBAL repair_cache.key_buffer_size = 128*1024*1024;
     CACHE INDEX TBL_NAME IN repair_cache;
     LOAD INDEX INTO CACHE TBL_NAME;
     REPAIR TABLE TBL_NAME ;
     SET GLOBAL repair_cache.key_buffer_size = 0;

If you intend to change a global variable but want to do so only for
the duration of a *Note `REPAIR TABLE': repair-table. operation to
minimally affect other users, save its value in a user variable and
restore it afterward.  For example:

     SET @old_myisam_sort_buffer_size = @@global.myisam_max_sort_file_size;
     SET GLOBAL myisam_max_sort_file_size = 100*1024*1024*1024;
     REPAIR TABLE tbl_name ;
     SET GLOBAL myisam_max_sort_file_size = @old_myisam_max_sort_file_size;

The system variables that affect *Note `REPAIR TABLE': repair-table.
can be set globally at server startup if you want the values to be in
effect by default. For example, add these lines to the server `my.cnf'
file:

     [mysqld]
     myisam_sort_buffer_size=256M
     key_buffer_size=1G
     myisam_max_sort_file_size=100G

These settings do not include `read_buffer_size'. Setting
`read_buffer_size' globally to a large value does so for all sessions
and can cause performance to suffer due to excessive memory allocation
for a server with many simultaneous sessions.


File: manual.info,  Node: miscellaneous-optimization-tips,  Prev: non-select-optimization,  Up: statement-optimization

8.3.3 Other Optimization Tips
-----------------------------

This section lists a number of miscellaneous tips for improving query
processing speed:

   * Use persistent connections to the database to avoid connection
     overhead. If you cannot use persistent connections and you are
     initiating many new connections to the database, you may want to
     change the value of the `thread_cache_size' variable.  See *Note
     server-parameters::.

   * Always check whether all your queries really use the indexes that
     you have created in the tables. In MySQL, you can do this with the
     *Note `EXPLAIN': explain.  statement. See *Note using-explain::.

   * Try to avoid complex *Note `SELECT': select.  queries on `MyISAM'
     tables that are updated frequently, to avoid problems with table
     locking that occur due to contention between readers and writers.

   * `MyISAM' supports concurrent inserts: If a table has no free
     blocks in the middle of the data file, you can *Note `INSERT':
     insert. new rows into it at the same time that other threads are
     reading from the table. If it is important to be able to do this,
     you should consider using the table in ways that avoid deleting
     rows.  Another possibility is to run *Note `OPTIMIZE TABLE':
     optimize-table. to defragment the table after you have deleted a
     lot of rows from it. This behavior is altered by setting the
     `concurrent_insert' variable.  You can force new rows to be
     appended (and therefore permit concurrent inserts), even in tables
     that have deleted rows.  See *Note concurrent-inserts::.

   * To fix any compression issues that may have occurred with
     `ARCHIVE' tables, you can use *Note `OPTIMIZE TABLE':
     optimize-table. See *Note archive-storage-engine::.

   * Use `ALTER TABLE ... ORDER BY EXPR1, EXPR2, ...' if you usually
     retrieve rows in `EXPR1, EXPR2, ...' order. By using this option
     after extensive changes to the table, you may be able to get
     higher performance.

   * In some cases, it may make sense to introduce a column that is
     `hashed' based on information from other columns. If this column
     is short, reasonably unique, and indexed, it may be much faster
     than a `wide' index on many columns. In MySQL, it is very easy to
     use this extra column:

          SELECT * FROM TBL_NAME
            WHERE HASH_COL=MD5(CONCAT(COL1,COL2))
            AND COL1='CONSTANT' AND COL2='CONSTANT';

   * For `MyISAM' tables that change frequently, you should try to
     avoid all variable-length columns (*Note `VARCHAR': char, *Note
     `BLOB': blob, and *Note `TEXT': blob.). The table uses dynamic row
     format if it includes even a single variable-length column. See
     *Note storage-engines::.

   * It is normally not useful to split a table into different tables
     just because the rows become large. In accessing a row, the
     biggest performance hit is the disk seek needed to find the first
     byte of the row. After finding the data, most modern disks can
     read the entire row fast enough for most applications. The only
     cases where splitting up a table makes an appreciable difference
     is if it is a `MyISAM' table using dynamic row format that you can
     change to a fixed row size, or if you very often need to scan the
     table but do not need most of the columns. See *Note
     storage-engines::.

   * If you often need to calculate results such as counts based on
     information from a lot of rows, it may be preferable to introduce
     a new table and update the counter in real time.  An update of the
     following form is very fast:

          UPDATE TBL_NAME SET COUNT_COL=COUNT_COL+1 WHERE KEY_COL=CONSTANT;

     This is very important when you use MySQL storage engines such as
     `MyISAM' that has only table-level locking (multiple readers with
     single writers). This also gives better performance with most
     database systems, because the row locking manager in this case has
     less to do.

   * If you need to collect statistics from large log tables, use
     summary tables instead of scanning the entire log table.
     Maintaining the summaries should be much faster than trying to
     calculate statistics `live.' Regenerating new summary tables from
     the logs when things change (depending on business decisions) is
     faster than changing the running application.

   * If possible, you should classify reports as `live' or as
     `statistical,' where data needed for statistical reports is
     created only from summary tables that are generated periodically
     from the live data.

   * Take advantage of the fact that columns have default values.
     Insert values explicitly only when the value to be inserted
     differs from the default. This reduces the parsing that MySQL must
     do and improves the insert speed.

   * In some cases, it is convenient to pack and store data into a
     *Note `BLOB': blob. column. In this case, you must provide code in
     your application to pack and unpack information, but this may save
     a lot of accesses at some stage. This is practical when you have
     data that does not conform well to a rows-and-columns table
     structure.

   * Normally, you should try to keep all data nonredundant (observing
     what is referred to in database theory as _third normal form_).
     However, there may be situations in which it can be advantageous to
     duplicate information or create summary tables to gain more speed.

   * Stored routines or UDFs (user-defined functions) may be a good way
     to gain performance for some tasks. See *Note stored-routines::,
     and *Note adding-functions::, for more information.

   * You can increase performance by caching queries or answers in your
     application and then executing many inserts or updates together.
     If your database system supports table locks, this should help to
     ensure that the index cache is only flushed once after all
     updates. You can also take advantage of MySQL's query cache to
     achieve similar results; see *Note query-cache::.

   * Use *Note `INSERT DELAYED': insert-delayed. when you do not need
     to know when your data is written. This reduces the overall
     insertion impact because many rows can be written with a single
     disk write.

   * Use `INSERT LOW_PRIORITY' when you want to give *Note `SELECT':
     select. statements higher priority than your inserts.

     Use `SELECT HIGH_PRIORITY' to get retrievals that jump the queue.
     That is, the *Note `SELECT': select. is executed even if there is
     another client waiting to do a write.

     `LOW_PRIORITY' and `HIGH_PRIORITY' have an effect only for storage
     engines that use only table-level locking (such as `MyISAM',
     `MEMORY', and `MERGE').

   * Use multiple-row *Note `INSERT': insert.  statements to store many
     rows with one SQL statement. Many SQL servers support this,
     including MySQL.

   * Use *Note `LOAD DATA INFILE': load-data. to load large amounts of
     data. This is faster than using *Note `INSERT': insert.
     statements.

   * Use `AUTO_INCREMENT' columns so that each row in a table can be
     identified by a single unique value.  unique values.

   * Use *Note `OPTIMIZE TABLE': optimize-table. once in a while to
     avoid fragmentation with dynamic-format `MyISAM' tables. See *Note
     myisam-table-formats::.

   * Use `MEMORY' (`HEAP') tables when possible to get more speed. See
     *Note memory-storage-engine::.  `MEMORY' tables are useful for
     noncritical data that is accessed often, such as information about
     the last displayed banner for users who don't have cookies enabled
     in their Web browser. User sessions are another alternative
     available in many Web application environments for handling
     volatile state data.

   * With Web servers, images and other binary assets should normally
     be stored as files. That is, store only a reference to the file
     rather than the file itself in the database.  Most Web servers are
     better at caching files than database contents, so using files is
     generally faster.

   * Columns with identical information in different tables should be
     declared to have identical data types so that joins based on the
     corresponding columns will be faster.

   * Try to keep column names simple. For example, in a table named
     `customer', use a column name of `name' instead of
     `customer_name'. To make your names portable to other SQL servers,
     you should keep them shorter than 18 characters.

   * If you need really high speed, you should take a look at the
     low-level interfaces for data storage that the different SQL
     servers support. For example, by accessing the MySQL `MyISAM'
     storage engine directly, you could get a speed increase of two to
     five times compared to using the SQL interface. To be able to do
     this, the data must be on the same server as the application, and
     usually it should only be accessed by one process (because
     external file locking is really slow). One could eliminate these
     problems by introducing low-level `MyISAM' commands in the MySQL
     server (this could be one easy way to get more performance if
     needed). By carefully designing the database interface, it should
     be quite easy to support this type of optimization.

   * If you are using numeric data, it is faster in many cases to
     access information from a database (using a live connection) than
     to access a text file. Information in the database is likely to be
     stored in a more compact format than in the text file, so
     accessing it involves fewer disk accesses. You also save code in
     your application because you need not parse your text files to
     find line and column boundaries.

   * Replication can provide a performance benefit for some operations.
     You can distribute client retrievals among replication servers to
     split up the load. To avoid slowing down the master while making
     backups, you can make backups using a slave server. See *Note
     replication::.

   * Declaring a `MyISAM' table with the `DELAY_KEY_WRITE=1' table
     option makes index updates faster because they are not flushed to
     disk until the table is closed. The downside is that if something
     kills the server while such a table is open, you should ensure
     that the table is okay by running the server with the
     `--myisam-recover' option, or by running *Note `myisamchk':
     myisamchk. before restarting the server. (However, even in this
     case, you should not lose anything by using `DELAY_KEY_WRITE',
     because the key information can always be generated from the data
     rows.)


File: manual.info,  Node: controlling-optimizer,  Next: optimization-indexes,  Prev: statement-optimization,  Up: optimization

8.4 Controlling the Query Optimizer
===================================

The task of the query optimizer is to find an optimal plan for
executing an SQL query. Because the difference in performance between
`good' and `bad' plans can be orders of magnitude (that is, seconds
versus hours or even days), most query optimizers, including that of
MySQL, perform a more or less exhaustive search for an optimal plan
among all possible query evaluation plans. For join queries, the number
of possible plans investigated by the MySQL optimizer grows
exponentially with the number of tables referenced in a query. For
small numbers of tables (typically less than 7 to 10) this is not a
problem.  However, when larger queries are submitted, the time spent in
query optimization may easily become the major bottleneck in the
server's performance.

MySQL 5.0.1 introduces a more flexible method for query optimization
that enables the user to control how exhaustive the optimizer is in its
search for an optimal query evaluation plan.  The general idea is that
the fewer plans that are investigated by the optimizer, the less time
it spends in compiling a query. On the other hand, because the
optimizer skips some plans, it may miss finding an optimal plan.

The behavior of the optimizer with respect to the number of plans it
evaluates can be controlled using two system variables:

   * The `optimizer_prune_level' variable tells the optimizer to skip
     certain plans based on estimates of the number of rows accessed
     for each table. Our experience shows that this kind of `educated
     guess' rarely misses optimal plans, and may dramatically reduce
     query compilation times. That is why this option is on
     (`optimizer_prune_level=1') by default. However, if you believe
     that the optimizer missed a better query plan, this option can be
     switched off (`optimizer_prune_level=0') with the risk that query
     compilation may take much longer. Note that, even with the use of
     this heuristic, the optimizer still explores a roughly exponential
     number of plans.

   * The `optimizer_search_depth' variable tells how far into the
     `future' of each incomplete plan the optimizer should look to
     evaluate whether it should be expanded further. Smaller values of
     `optimizer_search_depth' may result in orders of magnitude smaller
     query compilation times.  For example, queries with 12, 13, or
     more tables may easily require hours and even days to compile if
     `optimizer_search_depth' is close to the number of tables in the
     query. At the same time, if compiled with `optimizer_search_depth'
     equal to 3 or 4, the optimizer may compile in less than a minute
     for the same query. If you are unsure of what a reasonable value
     is for `optimizer_search_depth', this variable can be set to 0 to
     tell the optimizer to determine the value automatically.


File: manual.info,  Node: optimization-indexes,  Next: buffering-caching,  Prev: controlling-optimizer,  Up: optimization

8.5 Optimization and Indexes
============================

* Menu:

* column-indexes::               Column Indexes
* multiple-column-indexes::      Multiple-Column Indexes
* mysql-indexes::                How MySQL Uses Indexes
* myisam-index-statistics::      `MyISAM' Index Statistics Collection


File: manual.info,  Node: column-indexes,  Next: multiple-column-indexes,  Prev: optimization-indexes,  Up: optimization-indexes

8.5.1 Column Indexes
--------------------

All MySQL data types can be indexed. Use of indexes on the relevant
columns is the best way to improve the performance of *Note `SELECT':
select. operations.

The maximum number of indexes per table and the maximum index length is
defined per storage engine. See *Note storage-engines::. All storage
engines support at least 16 indexes per table and a total index length
of at least 256 bytes. Most storage engines have higher limits.

With `COL_NAME(N)' syntax in an index specification, you can create an
index that uses only the first N characters of a string column.
Indexing only a prefix of column values in this way can make the index
file much smaller. When you index a *Note `BLOB': blob. or *Note
`TEXT': blob. column, you _must_ specify a prefix length for the index.
For example:

     CREATE TABLE test (blob_col BLOB, INDEX(blob_col(10)));

Prefixes can be up to 1000 bytes long (767 bytes for `InnoDB' tables).
Note that prefix limits are measured in bytes, whereas the prefix
length in *Note `CREATE TABLE': create-table. statements is interpreted
as number of characters. _Be sure to take this into account when
specifying a prefix length for a column that uses a multi-byte
character set_.

You can also create `FULLTEXT' indexes. These are used for full-text
searches. Only the `MyISAM' storage engine supports `FULLTEXT' indexes
and only for *Note `CHAR': char, *Note `VARCHAR': char, and *Note
`TEXT': blob. columns. Indexing always takes place over the entire
column and column prefix indexing is not supported. For details, see
*Note fulltext-search::.

You can also create indexes on spatial data types. Currently, only
`MyISAM' supports R-tree indexes on spatial types. As of MySQL 5.0.16,
other storage engines use B-trees for indexing spatial types (except for
`ARCHIVE' and *Note `NDBCLUSTER': mysql-cluster, which do not support
spatial type indexing).

The `MEMORY' storage engine uses `HASH' indexes by default, but also
supports `BTREE' indexes.


File: manual.info,  Node: multiple-column-indexes,  Next: mysql-indexes,  Prev: column-indexes,  Up: optimization-indexes

8.5.2 Multiple-Column Indexes
-----------------------------

MySQL can create composite indexes (that is, indexes on multiple
columns). An index may consist of up to 16 columns. For certain data
types, you can index a prefix of the column (see *Note
column-indexes::).

MySQL can use multiple-column indexes for queries that test all the
columns in the index, or queries that test just the first column, the
first two columns, the first three columns, and so on. If you specify
the columns in the right order in the index definition, a single
composite index can speed up several kinds of queries on the same table.

A multiple-column index can be considered a sorted array, the rows of
which contain values that are created by concatenating the values of
the indexed columns.

*Note*:

As an alternative to a composite index, you can introduce a column that
is `hashed' based on information from other columns. If this column is
short, reasonably unique, and indexed, it might be faster than a `wide'
index on many columns. In MySQL, it is very easy to use this extra
column:

     SELECT * FROM TBL_NAME
       WHERE HASH_COL=MD5(CONCAT(COL1,COL2))
       AND COL1='CONSTANT' AND COL2='CONSTANT';

Suppose that a table has the following specification:

     CREATE TABLE test (
         id         INT NOT NULL,
         last_name  CHAR(30) NOT NULL,
         first_name CHAR(30) NOT NULL,
         PRIMARY KEY (id),
         INDEX name (last_name,first_name)
     );

The `name' index is an index over the `last_name' and `first_name'
columns. The index can be used for lookups in queries that specify
values in a known range for `last_name', or for both `last_name' and
`first_name'.  Therefore, the `name' index is used for lookups in the
following queries:

     SELECT * FROM test WHERE last_name='Widenius';

     SELECT * FROM test
       WHERE last_name='Widenius' AND first_name='Michael';

     SELECT * FROM test
       WHERE last_name='Widenius'
       AND (first_name='Michael' OR first_name='Monty');

     SELECT * FROM test
       WHERE last_name='Widenius'
       AND first_name >='M' AND first_name < 'N';

However, the `name' index is _not_ used for lookups in the following
queries:

     SELECT * FROM test WHERE first_name='Michael';

     SELECT * FROM test
       WHERE last_name='Widenius' OR first_name='Michael';

Suppose that you issue the following *Note `SELECT': select. statement:

     mysql> SELECT * FROM TBL_NAME WHERE col1=VAL1 AND col2=VAL2;

If a multiple-column index exists on `col1' and `col2', the appropriate
rows can be fetched directly. If separate single-column indexes exist on
`col1' and `col2', the optimizer attempts to use the Index Merge
optimization (see *Note index-merge-optimization::), or attempts to find
the most restrictive index by deciding which index excludes more rows
and using that index to fetch the rows.

If the table has a multiple-column index, any leftmost prefix of the
index can be used by the optimizer to find rows. For example, if you
have a three-column index on `(col1, col2, col3)', you have indexed
search capabilities on `(col1)', `(col1, col2)', and `(col1, col2,
col3)'.

MySQL cannot use the index to perform lookups if the columns do not
form a leftmost prefix of the index. Suppose that you have the *Note
`SELECT': select. statements shown here:

     SELECT * FROM TBL_NAME WHERE col1=VAL1;
     SELECT * FROM TBL_NAME WHERE col1=VAL1 AND col2=VAL2;

     SELECT * FROM TBL_NAME WHERE col2=VAL2;
     SELECT * FROM TBL_NAME WHERE col2=VAL2 AND col3=VAL3;

If an index exists on `(col1, col2, col3)', only the first two queries
use the index. The third and fourth queries do involve indexed columns,
but `(col2)' and `(col2, col3)' are not leftmost prefixes of `(col1,
col2, col3)'.


File: manual.info,  Node: mysql-indexes,  Next: myisam-index-statistics,  Prev: multiple-column-indexes,  Up: optimization-indexes

8.5.3 How MySQL Uses Indexes
----------------------------

Indexes are used to find rows with specific column values quickly.
Without an index, MySQL must begin with the first row and then read
through the entire table to find the relevant rows. The larger the
table, the more this costs. If the table has an index for the columns
in question, MySQL can quickly determine the position to seek to in the
middle of the data file without having to look at all the data. If a
table has 1,000 rows, this is at least 100 times faster than reading
sequentially. If you need to access most of the rows, it is faster to
read sequentially, because this minimizes disk seeks.

Most MySQL indexes (`PRIMARY KEY', `UNIQUE', `INDEX', and `FULLTEXT')
are stored in B-trees. Exceptions are that indexes on spatial data
types use R-trees, and that `MEMORY' tables also support hash indexes.

Strings are automatically prefix- and end-space compressed. See *Note
create-index::.

In general, indexes are used as described in the following discussion.
Characteristics specific to hash indexes (as used in `MEMORY' tables)
are described at the end of this section.

MySQL uses indexes for these operations:

   * To find the rows matching a `WHERE' clause quickly.

   * To eliminate rows from consideration. If there is a choice between
     multiple indexes, MySQL normally uses the index that finds the
     smallest number of rows.

   * To retrieve rows from other tables when performing joins.  MySQL
     can use indexes on columns more efficiently if they are declared
     as the same type and size. In this context, *Note `VARCHAR': char.
     and *Note `CHAR': char. are considered the same if they are
     declared as the same size. For example, `VARCHAR(10)' and
     `CHAR(10)' are the same size, but `VARCHAR(10)' and `CHAR(15)' are
     not.

     Comparison of dissimilar columns may prevent use of indexes if
     values cannot be compared directly without conversion.  Suppose
     that a numeric column is compared to a string column. For a given
     value such as `1' in the numeric column, it might compare equal to
     any number of values in the string column such as `'1'', `' 1'',
     `'00001'', or `'01.e1''. This rules out use of any indexes for the
     string column.

   * To find the `MIN()' or `MAX()' value for a specific indexed column
     KEY_COL. This is optimized by a preprocessor that checks whether
     you are using `WHERE KEY_PART_N = CONSTANT' on all key parts that
     occur before KEY_COL in the index. In this case, MySQL does a
     single key lookup for each `MIN()' or `MAX()' expression and
     replaces it with a constant. If all expressions are replaced with
     constants, the query returns at once. For example:

          SELECT MIN(KEY_PART2),MAX(KEY_PART2)
            FROM TBL_NAME WHERE KEY_PART1=10;

   * To sort or group a table if the sorting or grouping is done on a
     leftmost prefix of a usable key (for example, `ORDER BY KEY_PART1,
     KEY_PART2'). If all key parts are followed by `DESC', the key is
     read in reverse order. See *Note order-by-optimization::, and
     *Note group-by-optimization::.

   * In some cases, a query can be optimized to retrieve values without
     consulting the data rows. If a query uses only columns from a
     table that are numeric and that form a leftmost prefix for some
     key, the selected values may be retrieved from the index tree for
     greater speed:

          SELECT KEY_PART3 FROM TBL_NAME
            WHERE KEY_PART1=1

Suppose that you issue the following *Note `SELECT': select. statement:

     mysql> SELECT * FROM TBL_NAME WHERE col1=VAL1 AND col2=VAL2;

If a multiple-column index exists on `col1' and `col2', the appropriate
rows can be fetched directly. If separate single-column indexes exist on
`col1' and `col2', the optimizer will attempt to use the Index Merge
optimization (see *Note index-merge-optimization::), or attempt to find
the most restrictive index by deciding which index finds fewer rows and
using that index to fetch the rows.

If the table has a multiple-column index, any leftmost prefix of the
index can be used by the optimizer to find rows. For example, if you
have a three-column index on `(col1, col2, col3)', you have indexed
search capabilities on `(col1)', `(col1, col2)', and `(col1, col2,
col3)'.

MySQL cannot use an index if the columns do not form a leftmost prefix
of the index. Suppose that you have the *Note `SELECT': select.
statements shown here:

     SELECT * FROM TBL_NAME WHERE col1=VAL1;
     SELECT * FROM TBL_NAME WHERE col1=VAL1 AND col2=VAL2;

     SELECT * FROM TBL_NAME WHERE col2=VAL2;
     SELECT * FROM TBL_NAME WHERE col2=VAL2 AND col3=VAL3;

If an index exists on `(col1, col2, col3)', only the first two queries
use the index. The third and fourth queries do involve indexed columns,
but `(col2)' and `(col2, col3)' are not leftmost prefixes of `(col1,
col2, col3)'.

* B-Tree Index Characteristics *

A B-tree index can be used for column comparisons in expressions that
use the `=', `>', `>=', `<', `<=', or `BETWEEN' operators. The index
also can be used for `LIKE' comparisons if the argument to `LIKE' is a
constant string that does not start with a wildcard character. For
example, the following *Note `SELECT': select. statements use indexes:

     SELECT * FROM TBL_NAME WHERE KEY_COL LIKE 'Patrick%';
     SELECT * FROM TBL_NAME WHERE KEY_COL LIKE 'Pat%_ck%';

In the first statement, only rows with `'Patrick' <= KEY_COL <
'Patricl'' are considered. In the second statement, only rows with
`'Pat' <= KEY_COL < 'Pau'' are considered.

The following *Note `SELECT': select. statements do not use indexes:

     SELECT * FROM TBL_NAME WHERE KEY_COL LIKE '%Patrick%';
     SELECT * FROM TBL_NAME WHERE KEY_COL LIKE OTHER_COL;

In the first statement, the `LIKE' value begins with a wildcard
character. In the second statement, the `LIKE' value is not a constant.

If you use `... LIKE '%STRING%'' and STRING is longer than three
characters, MySQL uses the _Turbo Boyer-Moore algorithm_ to initialize
the pattern for the string and then uses this pattern to perform the
search more quickly.

A search using `COL_NAME IS NULL' employs indexes if COL_NAME is
indexed.

Any index that does not span all `AND' levels in the `WHERE' clause is
not used to optimize the query. In other words, to be able to use an
index, a prefix of the index must be used in every `AND' group.

The following `WHERE' clauses use indexes:

     ... WHERE INDEX_PART1=1 AND INDEX_PART2=2 AND OTHER_COLUMN=3
         /* INDEX = 1 OR INDEX = 2 */
     ... WHERE INDEX=1 OR A=10 AND INDEX=2
         /* optimized like "INDEX_PART1='hello'" */
     ... WHERE INDEX_PART1='hello' AND INDEX_PART3=5
         /* Can use index on INDEX1 but not on INDEX2 or INDEX3 */
     ... WHERE INDEX1=1 AND INDEX2=2 OR INDEX1=3 AND INDEX3=3;

These `WHERE' clauses do _not_ use indexes:

         /* INDEX_PART1 is not used */
     ... WHERE INDEX_PART2=1 AND INDEX_PART3=2

         /*  Index is not used in both parts of the WHERE clause  */
     ... WHERE INDEX=1 OR A=10

         /* No index spans all rows  */
     ... WHERE INDEX_PART1=1 OR INDEX_PART2=10

Sometimes MySQL does not use an index, even if one is available.  One
circumstance under which this occurs is when the optimizer estimates
that using the index would require MySQL to access a very large
percentage of the rows in the table. (In this case, a table scan is
likely to be much faster because it requires fewer seeks.) However, if
such a query uses `LIMIT' to retrieve only some of the rows, MySQL uses
an index anyway, because it can much more quickly find the few rows to
return in the result.

* Hash Index Characteristics *

Hash indexes have somewhat different characteristics from those just
discussed:

   * They are used only for equality comparisons that use the `=' or
     `<=>' operators (but are _very_ fast). They are not used for
     comparison operators such as `<' that find a range of values.

   * The optimizer cannot use a hash index to speed up `ORDER BY'
     operations. (This type of index cannot be used to search for the
     next entry in order.)

   * MySQL cannot determine approximately how many rows there are
     between two values (this is used by the range optimizer to decide
     which index to use). This may affect some queries if you change a
     `MyISAM' table to a hash-indexed `MEMORY' table.

   * Only whole keys can be used to search for a row. (With a B-tree
     index, any leftmost prefix of the key can be used to find rows.)


File: manual.info,  Node: myisam-index-statistics,  Prev: mysql-indexes,  Up: optimization-indexes

8.5.4 `MyISAM' Index Statistics Collection
------------------------------------------

Storage engines collect statistics about tables for use by the
optimizer. Table statistics are based on value groups, where a value
group is a set of rows with the same key prefix value. For optimizer
purposes, an important statistic is the average value group size.

MySQL uses the average value group size in the following ways:

   * To estimate how may rows must be read for each `ref' access

   * To estimate how many row a partial join will produce; that is, the
     number of rows that an operation of this form will produce:

          (...) JOIN TBL_NAME ON TBL_NAME.KEY = EXPR

As the average value group size for an index increases, the index is
less useful for those two purposes because the average number of rows
per lookup increases: For the index to be good for optimization
purposes, it is best that each index value target a small number of
rows in the table. When a given index value yields a large number of
rows, the index is less useful and MySQL is less likely to use it.

The average value group size is related to table cardinality, which is
the number of value groups. The *Note `SHOW INDEX': show-index.
statement displays a cardinality value based on N/S, where N is the
number of rows in the table and S is the average value group size. That
ratio yields an approximate number of value groups in the table.

For a join based on the `<=>' comparison operator, `NULL' is not
treated differently from any other value: `NULL <=> NULL', just as `N
<=> N' for any other N.

However, for a join based on the `=' operator, `NULL' is different from
non-`NULL' values: `EXPR1 = EXPR2' is not true when EXPR1 or EXPR2 (or
both) are `NULL'. This affects `ref' accesses for comparisons of the
form `TBL_NAME.KEY = EXPR': MySQL will not access the table if the
current value of EXPR is `NULL', because the comparison cannot be true.

For `=' comparisons, it does not matter how many `NULL' values are in
the table. For optimization purposes, the relevant value is the average
size of the non-`NULL' value groups. However, MySQL does not currently
enable that average size to be collected or used.

For `MyISAM' tables, you have some control over collection of table
statistics by means of the `myisam_stats_method' system variable. This
variable has three possible values, which differ as follows:

   * When `myisam_stats_method' is `nulls_equal', all `NULL' values are
     treated as identical (that is, they all form a single value group).

     If the `NULL' value group size is much higher than the average
     non-`NULL' value group size, this method skews the average value
     group size upward. This makes index appear to the optimizer to be
     less useful than it really is for joins that look for non-`NULL'
     values. Consequently, the `nulls_equal' method may cause the
     optimizer not to use the index for `ref' accesses when it should.

   * When `myisam_stats_method' is `nulls_unequal', `NULL' values are
     not considered the same. Instead, each `NULL' value forms a
     separate value group of size 1.

     If you have many `NULL' values, this method skews the average
     value group size downward. If the average non-`NULL' value group
     size is large, counting `NULL' values each as a group of size 1
     causes the optimizer to overestimate the value of the index for
     joins that look for non-`NULL' values. Consequently, the
     `nulls_unequal' method may cause the optimizer to use this index
     for `ref' lookups when other methods may be better.

   * When `myisam_stats_method' is `nulls_ignored', `NULL' values are
     ignored.

If you tend to use many joins that use `<=>' rather than `=', `NULL'
values are not special in comparisons and one `NULL' is equal to
another. In this case, `nulls_equal' is the appropriate statistics
method.

The `myisam_stats_method' system variable has global and session
values. Setting the global value affects `MyISAM' statistics collection
for all `MyISAM' tables. Setting the session value affects statistics
collection only for the current client connection. This means that you
can force a table's statistics to be regenerated with a given method
without affecting other clients by setting the session value of
`myisam_stats_method'.

To regenerate table statistics, you can use any of the following
methods:

   * Execute *Note `myisamchk --stats_method=METHOD_NAME --analyze':
     myisamchk.

   * Change the table to cause its statistics to go out of date (for
     example, insert a row and then delete it), and then set
     `myisam_stats_method' and issue an *Note `ANALYZE TABLE':
     analyze-table.  statement

Some caveats regarding the use of `myisam_stats_method':

   * You can force table statistics to be collected explicitly, as just
     described. However, MySQL may also collect statistics
     automatically. For example, if during the course of executing
     statements for a table, some of those statements modify the table,
     MySQL may collect statistics.  (This may occur for bulk inserts or
     deletes, or some *Note `ALTER TABLE': alter-table. statements, for
     example.) If this happens, the statistics are collected using
     whatever value `myisam_stats_method' has at the time. Thus, if you
     collect statistics using one method, but `myisam_stats_method' is
     set to the other method when a table's statistics are collected
     automatically later, the other method will be used.

   * There is no way to tell which method was used to generate
     statistics for a given `MyISAM' table.

   * `myisam_stats_method' applies only to `MyISAM' tables. Other
     storage engines have only one method for collecting table
     statistics. Usually it is closer to the `nulls_equal' method.


File: manual.info,  Node: buffering-caching,  Next: locking-issues,  Prev: optimization-indexes,  Up: optimization

8.6 Buffering and Caching
=========================

* Menu:

* myisam-key-cache::             The `MyISAM' Key Cache
* innodb-buffer-pool::           The `InnoDB' Buffer Pool
* query-cache::                  The MySQL Query Cache

MySQL uses several strategies that cache information in memory buffers
to increase performance.


File: manual.info,  Node: myisam-key-cache,  Next: innodb-buffer-pool,  Prev: buffering-caching,  Up: buffering-caching

8.6.1 The `MyISAM' Key Cache
----------------------------

* Menu:

* shared-key-cache::             Shared Key Cache Access
* multiple-key-caches::          Multiple Key Caches
* midpoint-insertion::           Midpoint Insertion Strategy
* index-preloading::             Index Preloading
* key-cache-block-size::         Key Cache Block Size
* key-cache-restructuring::      Restructuring a Key Cache

To minimize disk I/O, the `MyISAM' storage engine exploits a strategy
that is used by many database management systems. It employs a cache
mechanism to keep the most frequently accessed table blocks in memory:

   * For index blocks, a special structure called the _key cache_ (or
     _key buffer_) is maintained. The structure contains a number of
     block buffers where the most-used index blocks are placed.

   * For data blocks, MySQL uses no special cache. Instead it relies on
     the native operating system file system cache.

This section first describes the basic operation of the `MyISAM' key
cache. Then it discusses features that improve key cache performance
and that enable you to better control cache operation:

   * Access to the key cache no longer is serialized among threads.
     Multiple sessions can access the cache concurrently.

   * You can set up multiple key caches and assign table indexes to
     specific caches.

To control the size of the key cache, use the `key_buffer_size' system
variable. If this variable is set equal to zero, no key cache is used.
The key cache also is not used if the `key_buffer_size' value is too
small to allocate the minimal number of block buffers (8).

When the key cache is not operational, index files are accessed using
only the native file system buffering provided by the operating system.
(In other words, table index blocks are accessed using the same
strategy as that employed for table data blocks.)

An index block is a contiguous unit of access to the `MyISAM' index
files. Usually the size of an index block is equal to the size of nodes
of the index B-tree.  (Indexes are represented on disk using a B-tree
data structure.  Nodes at the bottom of the tree are leaf nodes. Nodes
above the leaf nodes are nonleaf nodes.)

All block buffers in a key cache structure are the same size.  This
size can be equal to, greater than, or less than the size of a table
index block. Usually one these two values is a multiple of the other.

When data from any table index block must be accessed, the server first
checks whether it is available in some block buffer of the key cache.
If it is, the server accesses data in the key cache rather than on
disk. That is, it reads from the cache or writes into it rather than
reading from or writing to disk.  Otherwise, the server chooses a cache
block buffer containing a different table index block (or blocks) and
replaces the data there by a copy of required table index block. As
soon as the new index block is in the cache, the index data can be
accessed.

If it happens that a block selected for replacement has been modified,
the block is considered `dirty.' In this case, prior to being replaced,
its contents are flushed to the table index from which it came.

Usually the server follows an _LRU (Least Recently Used)_ strategy:
When choosing a block for replacement, it selects the least recently
used index block. To make this choice easier, the key cache module
maintains all used blocks in a special list (_LRU chain_) ordered by
time of use. When a block is accessed, it is the most recently used and
is placed at the end of the list. When blocks need to be replaced,
blocks at the beginning of the list are the least recently used and
become the first candidates for eviction.

The `InnoDB' storage engine also uses an LRU algorithm, to manage its
buffer pool. See *Note innodb-buffer-pool::.


File: manual.info,  Node: shared-key-cache,  Next: multiple-key-caches,  Prev: myisam-key-cache,  Up: myisam-key-cache

8.6.1.1 Shared Key Cache Access
...............................

Threads can access key cache buffers simultaneously, subject to the
following conditions:

   * A buffer that is not being updated can be accessed by multiple
     sessions.

   * A buffer that is being updated causes sessions that need to use it
     to wait until the update is complete.

   * Multiple sessions can initiate requests that result in cache block
     replacements, as long as they do not interfere with each other
     (that is, as long as they need different index blocks, and thus
     cause different cache blocks to be replaced).

Shared access to the key cache enables the server to improve throughput
significantly.


File: manual.info,  Node: multiple-key-caches,  Next: midpoint-insertion,  Prev: shared-key-cache,  Up: myisam-key-cache

8.6.1.2 Multiple Key Caches
...........................

Shared access to the key cache improves performance but does not
eliminate contention among sessions entirely. They still compete for
control structures that manage access to the key cache buffers. To
reduce key cache access contention further, MySQL also provides
multiple key caches. This feature enables you to assign different table
indexes to different key caches.

Where there are multiple key caches, the server must know which cache
to use when processing queries for a given `MyISAM' table. By default,
all `MyISAM' table indexes are cached in the default key cache. To
assign table indexes to a specific key cache, use the *Note `CACHE
INDEX': cache-index.  statement (see *Note cache-index::). For example,
the following statement assigns indexes from the tables `t1', `t2', and
`t3' to the key cache named `hot_cache':

     mysql> CACHE INDEX t1, t2, t3 IN hot_cache;
     +---------+--------------------+----------+----------+
     | Table   | Op                 | Msg_type | Msg_text |
     +---------+--------------------+----------+----------+
     | test.t1 | assign_to_keycache | status   | OK       |
     | test.t2 | assign_to_keycache | status   | OK       |
     | test.t3 | assign_to_keycache | status   | OK       |
     +---------+--------------------+----------+----------+

The key cache referred to in a *Note `CACHE INDEX': cache-index.
statement can be created by setting its size with a *Note `SET GLOBAL':
set-option. parameter setting statement or by using server startup
options. For example:

     mysql> SET GLOBAL keycache1.key_buffer_size=128*1024;

To destroy a key cache, set its size to zero:

     mysql> SET GLOBAL keycache1.key_buffer_size=0;

Note that you cannot destroy the default key cache. Any attempt to do
this will be ignored:

     mysql> SET GLOBAL key_buffer_size = 0;

     mysql> SHOW VARIABLES LIKE 'key_buffer_size';
     +-----------------+---------+
     | Variable_name   | Value   |
     +-----------------+---------+
     | key_buffer_size | 8384512 |
     +-----------------+---------+

Key cache variables are structured system variables that have a name
and components. For `keycache1.key_buffer_size', `keycache1' is the
cache variable name and `key_buffer_size' is the cache component. See
*Note structured-system-variables::, for a description of the syntax
used for referring to structured key cache system variables.

By default, table indexes are assigned to the main (default) key cache
created at the server startup. When a key cache is destroyed, all
indexes assigned to it are reassigned to the default key cache.

For a busy server, you can use a strategy that involves three key
caches:

   * A `hot' key cache that takes up 20% of the space allocated for all
     key caches. Use this for tables that are heavily used for searches
     but that are not updated.

   * A `cold' key cache that takes up 20% of the space allocated for
     all key caches. Use this cache for medium-sized, intensively
     modified tables, such as temporary tables.

   * A `warm' key cache that takes up 60% of the key cache space.
     Employ this as the default key cache, to be used by default for
     all other tables.

One reason the use of three key caches is beneficial is that access to
one key cache structure does not block access to the others. Statements
that access tables assigned to one cache do not compete with statements
that access tables assigned to another cache. Performance gains occur
for other reasons as well:

   * The hot cache is used only for retrieval queries, so its contents
     are never modified. Consequently, whenever an index block needs to
     be pulled in from disk, the contents of the cache block chosen for
     replacement need not be flushed first.

   * For an index assigned to the hot cache, if there are no queries
     requiring an index scan, there is a high probability that the
     index blocks corresponding to nonleaf nodes of the index B-tree
     remain in the cache.

   * An update operation most frequently executed for temporary tables
     is performed much faster when the updated node is in the cache and
     need not be read in from disk first. If the size of the indexes of
     the temporary tables are comparable with the size of cold key
     cache, the probability is very high that the updated node is in the
     cache.

The *Note `CACHE INDEX': cache-index. statement sets up an association
between a table and a key cache, but the association is lost each time
the server restarts. If you want the association to take effect each
time the server starts, one way to accomplish this is to use an option
file: Include variable settings that configure your key caches, and an
`init-file' option that names a file containing *Note `CACHE INDEX':
cache-index.  statements to be executed. For example:

     key_buffer_size = 4G
     hot_cache.key_buffer_size = 2G
     cold_cache.key_buffer_size = 2G
     init_file=/PATH/TO/DATA-DIRECTORY/mysqld_init.sql

The statements in `mysqld_init.sql' are executed each time the server
starts. The file should contain one SQL statement per line. The
following example assigns several tables each to `hot_cache' and
`cold_cache':

     CACHE INDEX db1.t1, db1.t2, db2.t3 IN hot_cache
     CACHE INDEX db1.t4, db2.t5, db2.t6 IN cold_cache


File: manual.info,  Node: midpoint-insertion,  Next: index-preloading,  Prev: multiple-key-caches,  Up: myisam-key-cache

8.6.1.3 Midpoint Insertion Strategy
...................................

By default, the key cache management system uses a simple LRU strategy
for choosing key cache blocks to be evicted, but it also supports a
more sophisticated method called the _midpoint insertion strategy._

When using the midpoint insertion strategy, the LRU chain is divided
into two parts: a hot sublist and a warm sublist. The division point
between two parts is not fixed, but the key cache management system
takes care that the warm part is not `too short,' always containing at
least `key_cache_division_limit' percent of the key cache blocks.
`key_cache_division_limit' is a component of structured key cache
variables, so its value is a parameter that can be set per cache.

When an index block is read from a table into the key cache, it is
placed at the end of the warm sublist. After a certain number of hits
(accesses of the block), it is promoted to the hot sublist. At present,
the number of hits required to promote a block (3) is the same for all
index blocks.

A block promoted into the hot sublist is placed at the end of the list.
The block then circulates within this sublist. If the block stays at
the beginning of the sublist for a long enough time, it is demoted to
the warm sublist. This time is determined by the value of the
`key_cache_age_threshold' component of the key cache.

The threshold value prescribes that, for a key cache containing N
blocks, the block at the beginning of the hot sublist not accessed
within the last `N * key_cache_age_threshold / 100' hits is to be moved
to the beginning of the warm sublist. It then becomes the first
candidate for eviction, because blocks for replacement always are taken
from the beginning of the warm sublist.

The midpoint insertion strategy enables you to keep more-valued blocks
always in the cache. If you prefer to use the plain LRU strategy, leave
the `key_cache_division_limit' value set to its default of 100.

The midpoint insertion strategy helps to improve performance when
execution of a query that requires an index scan effectively pushes out
of the cache all the index blocks corresponding to valuable high-level
B-tree nodes. To avoid this, you must use a midpoint insertion strategy
with the `key_cache_division_limit' set to much less than 100. Then
valuable frequently hit nodes are preserved in the hot sublist during
an index scan operation as well.


File: manual.info,  Node: index-preloading,  Next: key-cache-block-size,  Prev: midpoint-insertion,  Up: myisam-key-cache

8.6.1.4 Index Preloading
........................

If there are enough blocks in a key cache to hold blocks of an entire
index, or at least the blocks corresponding to its nonleaf nodes, it
makes sense to preload the key cache with index blocks before starting
to use it. Preloading enables you to put the table index blocks into a
key cache buffer in the most efficient way: by reading the index blocks
from disk sequentially.

Without preloading, the blocks are still placed into the key cache as
needed by queries. Although the blocks will stay in the cache, because
there are enough buffers for all of them, they are fetched from disk in
random order, and not sequentially.

To preload an index into a cache, use the *Note `LOAD INDEX INTO
CACHE': load-index. statement. For example, the following statement
preloads nodes (index blocks) of indexes of the tables `t1' and `t2':

     mysql> LOAD INDEX INTO CACHE t1, t2 IGNORE LEAVES;
     +---------+--------------+----------+----------+
     | Table   | Op           | Msg_type | Msg_text |
     +---------+--------------+----------+----------+
     | test.t1 | preload_keys | status   | OK       |
     | test.t2 | preload_keys | status   | OK       |
     +---------+--------------+----------+----------+

The `IGNORE LEAVES' modifier causes only blocks for the nonleaf nodes
of the index to be preloaded.  Thus, the statement shown preloads all
index blocks from `t1', but only blocks for the nonleaf nodes from `t2'.

If an index has been assigned to a key cache using a *Note `CACHE
INDEX': cache-index. statement, preloading places index blocks into
that cache. Otherwise, the index is loaded into the default key cache.


File: manual.info,  Node: key-cache-block-size,  Next: key-cache-restructuring,  Prev: index-preloading,  Up: myisam-key-cache

8.6.1.5 Key Cache Block Size
............................

It is possible to specify the size of the block buffers for an
individual key cache using the `key_cache_block_size' variable. This
permits tuning of the performance of I/O operations for index files.

The best performance for I/O operations is achieved when the size of
read buffers is equal to the size of the native operating system I/O
buffers. But setting the size of key nodes equal to the size of the I/O
buffer does not always ensure the best overall performance. When
reading the big leaf nodes, the server pulls in a lot of unnecessary
data, effectively preventing reading other leaf nodes.

To control the size of blocks in the `.MYI' index file of `MyISAM'
tables, use the `--myisam-block-size' option at server startup.


File: manual.info,  Node: key-cache-restructuring,  Prev: key-cache-block-size,  Up: myisam-key-cache

8.6.1.6 Restructuring a Key Cache
.................................

A key cache can be restructured at any time by updating its parameter
values. For example:

     mysql> SET GLOBAL cold_cache.key_buffer_size=4*1024*1024;

If you assign to either the `key_buffer_size' or `key_cache_block_size'
key cache component a value that differs from the component's current
value, the server destroys the cache's old structure and creates a new
one based on the new values. If the cache contains any dirty blocks,
the server saves them to disk before destroying and re-creating the
cache. Restructuring does not occur if you change other key cache
parameters.

When restructuring a key cache, the server first flushes the contents
of any dirty buffers to disk. After that, the cache contents become
unavailable. However, restructuring does not block queries that need to
use indexes assigned to the cache.  Instead, the server directly
accesses the table indexes using native file system caching. File
system caching is not as efficient as using a key cache, so although
queries execute, a slowdown can be anticipated. After the cache has been
restructured, it becomes available again for caching indexes assigned
to it, and the use of file system caching for the indexes ceases.


File: manual.info,  Node: innodb-buffer-pool,  Next: query-cache,  Prev: myisam-key-cache,  Up: buffering-caching

8.6.2 The `InnoDB' Buffer Pool
------------------------------

*Note `InnoDB': innodb-storage-engine. maintains a buffer pool for
caching data and indexes in memory.  *Note `InnoDB':
innodb-storage-engine. manages the pool as a list, using a least
recently used (LRU) algorithm incorporating a midpoint insertion
strategy. When room is needed to add a new block to the pool, *Note
`InnoDB': innodb-storage-engine. evicts the least recently used block
and adds the new block to the middle of the list. The midpoint
insertion strategy in effect causes the list to be treated as two
sublists:

   * At the head, a sublist of `new' (or `young') blocks that have been
     recently used.

   * At the tail, a sublist of `old' blocks that are less recently used.

As a result of the algorithm, the new sublist contains blocks that are
heavily used by queries. The old sublist contains less-used blocks, and
candidates for eviction are taken from this sublist.

The LRU algorithm operates as follows by default:

   * 3/8 of the buffer pool is devoted to the old sublist.

   * The midpoint of the list is the boundary where the tail of the new
     sublist meets the head of the old sublist.

   * When *Note `InnoDB': innodb-storage-engine. reads a block into the
     buffer pool, it initially inserts it at the midpoint (the head of
     the old sublist). A block can be read in as a result of two types
     of read requests: Because it is required (for example, to satisfy
     query execution), or as part of read-ahead performed in
     anticipation that it will be required.

   * The first access to a block in the old sublist makes it `young',
     causing it to move to the head of the buffer pool (the head of the
     new sublist). If the block was read in because it was required,
     the first access occurs immediately and the block is made young.
     If the block was read in due to read-ahead, the first access does
     not occur immediately (and might not occur at all before the block
     is evicted).

   * As long as no accesses occur for a block in the pool, it `ages' by
     moving toward the tail of the list.  Blocks in both the new and
     old sublists age as other blocks are made new. Blocks in the old
     sublist also age as blocks are inserted at the midpoint.
     Eventually, a block that remains unused for long enough reaches
     the tail of the old sublist and is evicted.

In the default operation of the buffer pool, a block when read in is
loaded at the midpoint and then moved immediately to the head of the
new sublist as soon as an access occurs. In the case of a table scan
(such as performed for a *Note `mysqldump': mysqldump. operation), each
block read by the scan ends up moving to the head of the new sublist
because multiple rows are accessed from each block. This occurs even for
a one-time scan, where the blocks are not otherwise used by other
queries. Blocks may also be loaded by the read-ahead background thread
and then moved to the head of the new sublist by a single access. These
effects can be disadvantageous because they push blocks that are in
heavy use by other queries out of the new sublist to the old sublist
where they become subject to eviction.

The `innodb_buffer_pool_size' system variable specifies the size of the
buffer pool. If your buffer pool is small and you have sufficient
memory, making the pool larger can improve performance by reducing the
amount of disk I/O needed as queries access *Note `InnoDB':
innodb-storage-engine. tables.

The `MyISAM' storage engine also uses an LRU algorithm, to manage its
key cache. See *Note myisam-key-cache::.


File: manual.info,  Node: query-cache,  Prev: innodb-buffer-pool,  Up: buffering-caching

8.6.3 The MySQL Query Cache
---------------------------

* Menu:

* query-cache-operation::        How the Query Cache Operates
* query-cache-in-select::        Query Cache `SELECT' Options
* query-cache-configuration::    Query Cache Configuration
* query-cache-status-and-maintenance::  Query Cache Status and Maintenance

The query cache stores the text of a *Note `SELECT': select. statement
together with the corresponding result that was sent to the client. If
an identical statement is received later, the server retrieves the
results from the query cache rather than parsing and executing the
statement again. The query cache is shared among sessions, so a result
set generated by one client can be sent in response to the same query
issued by another client.

The query cache can be useful in an environment where you have tables
that do not change very often and for which the server receives many
identical queries. This is a typical situation for many Web servers
that generate many dynamic pages based on database content.

The query cache does not return stale data. When tables are modified,
any relevant entries in the query cache are flushed.

*Note*:

The query cache does not work in an environment where you have multiple
*Note `mysqld': mysqld. servers updating the same `MyISAM' tables.

*Note*:

The query cache is not used for prepared statements. If you are using
prepared statements, consider that these statements will not be
satisfied by the query cache. See *Note c-api-prepared-statements::.

Some performance data for the query cache follows. These results were
generated by running the MySQL benchmark suite on a Linux Alpha
2x500MHz system with 2GB RAM and a 64MB query cache.

   * If all the queries you are performing are simple (such as
     selecting a row from a table with one row), but still differ so
     that the queries cannot be cached, the overhead for having the
     query cache active is 13%. This could be regarded as the worst
     case scenario. In real life, queries tend to be much more
     complicated, so the overhead normally is significantly lower.

   * Searches for a single row in a single-row table are 238% faster
     with the query cache than without it. This can be regarded as
     close to the minimum speedup to be expected for a query that is
     cached.

To disable the query cache at server startup, set the
`query_cache_size' system variable to 0. By disabling the query cache
code, there is no noticeable overhead. If you build MySQL from source,
query cache capabilities can be excluded from the server entirely by
invoking `configure' with the `--without-query-cache' option.

The query cache offers the potential for substantial performance
improvement, but you should not assume that it will do so under all
circumstances. With some query cache configurations or server
workloads, you might actually see a performance decrease:

   * Be cautious about sizing the query cache excessively large, which
     increases the overhead required to maintain the cache, possibly
     beyond the benefit of enabling it. Sizes in tens of megabytes are
     usually beneficial. Sizes in the hundreds of megabytes might not
     be.

   * Server workload has a significant effect on query cache
     efficiency. A query mix consisting almost entirely of a fixed set
     of *Note `SELECT': select.  statements is much more likely to
     benefit from enabling the cache than a mix in which frequent *Note
     `INSERT': insert. statements cause continual invalidation of
     results in the cache. In some cases, a workaround is to use the
     `SQL_NO_CACHE' option to prevent results from even entering the
     cache for *Note `SELECT': select. statements that use frequently
     modified tables. (See *Note query-cache-in-select::.)

To verify that enabling the query cache is beneficial, test the
operation of your MySQL server with the cache enabled and disabled.
Then retest periodically because query cache efficiency may change as
server workload changes.


File: manual.info,  Node: query-cache-operation,  Next: query-cache-in-select,  Prev: query-cache,  Up: query-cache

8.6.3.1 How the Query Cache Operates
....................................

This section describes how the query cache works when it is
operational. *Note query-cache-configuration::, describes how to
control whether it is operational.

Incoming queries are compared to those in the query cache before
parsing, so the following two queries are regarded as different by the
query cache:

     SELECT * FROM TBL_NAME
     Select * from TBL_NAME

Queries must be _exactly_ the same (byte for byte) to be seen as
identical. In addition, query strings that are identical may be treated
as different for other reasons. Queries that use different databases,
different protocol versions, or different default character sets are
considered different queries and are cached separately.

Because comparison of a query against those in the cache occurs before
parsing, the cache is not used for queries of the following types:

   * Prepared statements

   * Queries that are a subquery of an outer query

   * Queries executed within the body of a stored function or trigger

Before a query result is fetched from the query cache, MySQL checks
whether the user has *Note `SELECT': select. privilege for all
databases and tables involved. If this is not the case, the cached
result is not used.

If a query result is returned from query cache, the server increments
the `Qcache_hits' status variable, not `Com_select'. See *Note
query-cache-status-and-maintenance::.

If a table changes, all cached queries that use the table become
invalid and are removed from the cache. This includes queries that use
`MERGE' tables that map to the changed table. A table can be changed by
many types of statements, such as *Note `INSERT': insert, *Note
`UPDATE': update, *Note `DELETE': delete, *Note `TRUNCATE TABLE':
truncate-table, *Note `ALTER TABLE': alter-table, *Note `DROP TABLE':
drop-table, or *Note `DROP DATABASE': drop-database.

The query cache also works within transactions when using `InnoDB'
tables.

In MySQL 5.0, the result from a *Note `SELECT': select. query on a view
is cached.

Before MySQL 5.0, a query that began with a leading comment could be
cached, but could not be fetched from the cache. This problem is fixed
in MySQL 5.0.

The query cache works for `SELECT SQL_CALC_FOUND_ROWS ...' queries and
stores a value that is returned by a following `SELECT FOUND_ROWS()'
query.  `FOUND_ROWS()' returns the correct value even if the preceding
query was fetched from the cache because the number of found rows is
also stored in the cache. The `SELECT FOUND_ROWS()' query itself cannot
be cached.

A query cannot be cached if it contains any of the functions shown in
the following table.

`BENCHMARK()'            `CONNECTION_ID()'        `CONVERT_TZ()'
`CURDATE()'              `CURRENT_DATE()'         `CURRENT_TIME()'
`CURRENT_TIMESTAMP()'    `CURTIME()'              `DATABASE()'
`ENCRYPT()' with one     `FOUND_ROWS()'           `GET_LOCK()'
parameter                                         
`LAST_INSERT_ID()'       `LOAD_FILE()'            `MASTER_POS_WAIT()'
`NOW()'                  `RAND()'                 `RELEASE_LOCK()'
`SLEEP()'                `SYSDATE()'              `UNIX_TIMESTAMP()' with
                                                  no parameters
`USER()'                 `UUID()'                 

A query also is not cached under these conditions:

   * It refers to user-defined functions (UDFs) or stored functions.

   * It refers to user variables or local stored program variables.

   * It refers to tables in the `mysql' or `INFORMATION_SCHEMA' system
     database.

   * It is of any of the following forms:

          SELECT ... LOCK IN SHARE MODE
          SELECT ... FOR UPDATE
          SELECT ... INTO OUTFILE ...
          SELECT ... INTO DUMPFILE ...
          SELECT * FROM ... WHERE autoincrement_col IS NULL

     The last form is not cached because it is used as the ODBC
     workaround for obtaining the last insert ID value. See the
     Connector/ODBC section of *Note connectors-apis::.

     Statements within transactions that use `SERIALIZABLE' isolation
     level also cannot be cached because they use `LOCK IN SHARE MODE'
     locking.

   * It was issued as a prepared statement, even if no placeholders
     were employed. For example, the query used here is not cached:

          char *my_sql_stmt = "SELECT a, b FROM table_c";
          /* ... */
          mysql_stmt_prepare(stmt, my_sql_stmt, strlen(my_sql_stmt));

     See *Note c-api-prepared-statements::.

   * It uses `TEMPORARY' tables.

   * It does not use any tables.

   * It generates warnings.

   * The user has a column-level privilege for any of the involved
     tables.


File: manual.info,  Node: query-cache-in-select,  Next: query-cache-configuration,  Prev: query-cache-operation,  Up: query-cache

8.6.3.2 Query Cache `SELECT' Options
....................................

Two query cache-related options may be specified in *Note `SELECT':
select. statements:

   * `SQL_CACHE'

     The query result is cached if it is cacheable and the value of the
     `query_cache_type' system variable is `ON' or `DEMAND'.

   * `SQL_NO_CACHE'

     The query result is not cached.

Examples:

     SELECT SQL_CACHE id, name FROM customer;
     SELECT SQL_NO_CACHE id, name FROM customer;


File: manual.info,  Node: query-cache-configuration,  Next: query-cache-status-and-maintenance,  Prev: query-cache-in-select,  Up: query-cache

8.6.3.3 Query Cache Configuration
.................................

The `have_query_cache' server system variable indicates whether the
query cache is available:

     mysql> SHOW VARIABLES LIKE 'have_query_cache';
     +------------------+-------+
     | Variable_name    | Value |
     +------------------+-------+
     | have_query_cache | YES   |
     +------------------+-------+

When using a standard MySQL binary, this value is always `YES', even if
query caching is disabled.

Several other system variables control query cache operation.  These
can be set in an option file or on the command line when starting *Note
`mysqld': mysqld. The query cache system variables all have names that
begin with `query_cache_'. They are described briefly in *Note
server-system-variables::, with additional configuration information
given here.

To set the size of the query cache, set the `query_cache_size' system
variable. Setting it to 0 disables the query cache. The default size is
0, so the query cache is disabled by default.

Be careful not to set the size of the cache too large. Due to the need
for threads to lock the cache during updates, you may see lock
contention issues with a very large cache.

*Note*:

When using the Windows Configuration Wizard to install or configure
MySQL, the default value for `query_cache_size' will be configured
automatically for you based on the different configuration types
available. When using the Windows Configuration Wizard, the query cache
may be enabled (that is, set to a nonzero value) due to the selected
configuration. The query cache is also controlled by the setting of the
`query_cache_type' variable.  You should check the values of these
variables as set in your `my.ini' file after configuration has taken
place.

When you set `query_cache_size' to a nonzero value, keep in mind that
the query cache needs a minimum size of about 40KB to allocate its
structures. (The exact size depends on system architecture.) If you set
the value too small, you'll get a warning, as in this example:

     mysql> SET GLOBAL query_cache_size = 40000;
     Query OK, 0 rows affected, 1 warning (0.00 sec)

     mysql> SHOW WARNINGS\G
     *************************** 1. row ***************************
       Level: Warning
        Code: 1282
     Message: Query cache failed to set size 39936;
              new query cache size is 0

     mysql> SET GLOBAL query_cache_size = 41984;
     Query OK, 0 rows affected (0.00 sec)

     mysql> SHOW VARIABLES LIKE 'query_cache_size';
     +------------------+-------+
     | Variable_name    | Value |
     +------------------+-------+
     | query_cache_size | 41984 |
     +------------------+-------+

For the query cache to actually be able to hold any query results, its
size must be set larger:

     mysql> SET GLOBAL query_cache_size = 1000000;
     Query OK, 0 rows affected (0.04 sec)

     mysql> SHOW VARIABLES LIKE 'query_cache_size';
     +------------------+--------+
     | Variable_name    | Value  |
     +------------------+--------+
     | query_cache_size | 999424 |
     +------------------+--------+
     1 row in set (0.00 sec)

The `query_cache_size' value is aligned to the nearest 1024 byte block.
The value reported may therefore be different from the value that you
assign.

If the query cache size is greater than 0, the `query_cache_type'
variable influences how it works. This variable can be set to the
following values:

   * A value of `0' or `OFF' prevents caching or retrieval of cached
     results.

   * A value of `1' or `ON' enables caching except of those statements
     that begin with `SELECT SQL_NO_CACHE'.

   * A value of `2' or `DEMAND' causes caching of only those statements
     that begin with `SELECT SQL_CACHE'.

Setting the `GLOBAL' `query_cache_type' value determines query cache
behavior for all clients that connect after the change is made.
Individual clients can control cache behavior for their own connection
by setting the `SESSION' `query_cache_type' value. For example, a
client can disable use of the query cache for its own queries like this:

     mysql> SET SESSION query_cache_type = OFF;

If you set `query_cache_type' at server startup (rather than at runtime
with a *Note `SET': set-option.  statement), only the numeric values
are permitted.

To control the maximum size of individual query results that can be
cached, set the `query_cache_limit' system variable. The default value
is 1MB.

When a query is to be cached, its result (the data sent to the client)
is stored in the query cache during result retrieval.  Therefore the
data usually is not handled in one big chunk.  The query cache
allocates blocks for storing this data on demand, so when one block is
filled, a new block is allocated.  Because memory allocation operation
is costly (timewise), the query cache allocates blocks with a minimum
size given by the `query_cache_min_res_unit' system variable. When a
query is executed, the last result block is trimmed to the actual data
size so that unused memory is freed. Depending on the types of queries
your server executes, you might find it helpful to tune the value of
`query_cache_min_res_unit':

   * The default value of `query_cache_min_res_unit' is 4KB. This
     should be adequate for most cases.

   * If you have a lot of queries with small results, the default block
     size may lead to memory fragmentation, as indicated by a large
     number of free blocks. Fragmentation can force the query cache to
     prune (delete) queries from the cache due to lack of memory. In
     this case, you should decrease the value of
     `query_cache_min_res_unit'.  The number of free blocks and queries
     removed due to pruning are given by the values of the
     `Qcache_free_blocks' and `Qcache_lowmem_prunes' status variables.

   * If most of your queries have large results (check the
     `Qcache_total_blocks' and `Qcache_queries_in_cache' status
     variables), you can increase performance by increasing
     `query_cache_min_res_unit'.  However, be careful to not make it
     too large (see the previous item).


File: manual.info,  Node: query-cache-status-and-maintenance,  Prev: query-cache-configuration,  Up: query-cache

8.6.3.4 Query Cache Status and Maintenance
..........................................

To check whether the query cache is present in your MySQL server, use
the following statement:

     mysql> SHOW VARIABLES LIKE 'have_query_cache';
     +------------------+-------+
     | Variable_name    | Value |
     +------------------+-------+
     | have_query_cache | YES   |
     +------------------+-------+

You can defragment the query cache to better utilize its memory with
the *Note `FLUSH QUERY CACHE': flush. statement. The statement does not
remove any queries from the cache.

The `RESET QUERY CACHE' statement removes all query results from the
query cache. The *Note `FLUSH TABLES': flush.  statement also does this.

To monitor query cache performance, use *Note `SHOW STATUS':
show-status. to view the cache status variables:

     mysql> SHOW STATUS LIKE 'Qcache%';
     +-------------------------+--------+
     | Variable_name           | Value  |
     +-------------------------+--------+
     | Qcache_free_blocks      | 36     |
     | Qcache_free_memory      | 138488 |
     | Qcache_hits             | 79570  |
     | Qcache_inserts          | 27087  |
     | Qcache_lowmem_prunes    | 3114   |
     | Qcache_not_cached       | 22989  |
     | Qcache_queries_in_cache | 415    |
     | Qcache_total_blocks     | 912    |
     +-------------------------+--------+

Descriptions of each of these variables are given in *Note
server-status-variables::. Some uses for them are described here.

The total number of *Note `SELECT': select.  queries is given by this
formula:

       Com_select
     + Qcache_hits
     + queries with errors found by parser

The `Com_select' value is given by this formula:

       Qcache_inserts
     + Qcache_not_cached
     + queries with errors found during the column-privileges check

The query cache uses variable-length blocks, so `Qcache_total_blocks'
and `Qcache_free_blocks' may indicate query cache memory fragmentation.
After *Note `FLUSH QUERY CACHE': flush, only a single free block
remains.

Every cached query requires a minimum of two blocks (one for the query
text and one or more for the query results). Also, every table that is
used by a query requires one block.  However, if two or more queries
use the same table, only one table block needs to be allocated.

The information provided by the `Qcache_lowmem_prunes' status variable
can help you tune the query cache size. It counts the number of queries
that have been removed from the cache to free up memory for caching new
queries. The query cache uses a least recently used (LRU) strategy to
decide which queries to remove from the cache. Tuning information is
given in *Note query-cache-configuration::.


File: manual.info,  Node: locking-issues,  Next: optimizing-database-structure,  Prev: buffering-caching,  Up: optimization

8.7 Locking Issues
==================

* Menu:

* internal-locking::             Internal Locking Methods
* table-locking::                Table Locking Issues
* concurrent-inserts::           Concurrent Inserts
* external-locking::             External Locking

MySQL manages contention for table contents using locking:

   * Internal locking is performed within the MySQL server itself to
     manage contention for table contents by multiple threads.  This
     type of locking is internal because it is performed entirely by
     the server and involves no other programs. See *Note
     internal-locking::.

   * External locking occurs when the server and other programs lock
     *Note `MyISAM': myisam-storage-engine. table files to coordinate
     among themselves which program can access the tables at which
     time. See *Note external-locking::.


File: manual.info,  Node: internal-locking,  Next: table-locking,  Prev: locking-issues,  Up: locking-issues

8.7.1 Internal Locking Methods
------------------------------

This section discusses internal locking; that is, locking performed
within the MySQL server itself to manage contention for table contents
by multiple sessions. This type of locking is internal because it is
performed entirely by the server and involves no other programs.
External locking occurs when the server and other programs lock *Note
`MyISAM': myisam-storage-engine. table files to coordinate among
themselves which program can access the tables at which time. See *Note
external-locking::.

MySQL uses table-level locking for `MyISAM', `MEMORY' and `MERGE'
tables, page-level locking for `BDB' tables, and row-level locking for
`InnoDB' tables.

In many cases, you can make an educated guess about which locking type
is best for an application, but generally it is difficult to say that a
given lock type is better than another.  Everything depends on the
application and different parts of an application may require different
lock types.

To decide whether you want to use a storage engine with row-level
locking, you should look at what your application does and what mix of
select and update statements it uses. For example, most Web
applications perform many selects, relatively few deletes, updates
based mainly on key values, and inserts into a few specific tables. The
base MySQL `MyISAM' setup is very well tuned for this.

Table locking in MySQL is deadlock-free for storage engines that use
table-level locking. Deadlock avoidance is managed by always requesting
all needed locks at once at the beginning of a query and always locking
the tables in the same order.

MySQL grants table write locks as follows:

  1. If there are no locks on the table, put a write lock on it.

  2. Otherwise, put the lock request in the write lock queue.

MySQL grants table read locks as follows:

  1. If there are no write locks on the table, put a read lock on it.

  2. Otherwise, put the lock request in the read lock queue.

Table updates are given higher priority than table retrievals.
Therefore, when a lock is released, the lock is made available to the
requests in the write lock queue and then to the requests in the read
lock queue. This ensures that updates to a table are not `starved' even
if there is heavy *Note `SELECT': select. activity for the table.
However, if you have many updates for a table, *Note `SELECT': select.
statements wait until there are no more updates.

For information on altering the priority of reads and writes, see *Note
table-locking::.

You can analyze the table lock contention on your system by checking the
`Table_locks_immediate' and `Table_locks_waited' status variables,
which indicate the number of times that requests for table locks could
be granted immediately and the number that had to wait, respectively:

     mysql> SHOW STATUS LIKE 'Table%';
     +-----------------------+---------+
     | Variable_name         | Value   |
     +-----------------------+---------+
     | Table_locks_immediate | 1151552 |
     | Table_locks_waited    | 15324   |
     +-----------------------+---------+

The `MyISAM' storage engine supports concurrent inserts to reduce
contention between readers and writers for a given table: If a `MyISAM'
table has no free blocks in the middle of the data file, rows are
always inserted at the end of the data file. In this case, you can
freely mix concurrent *Note `INSERT': insert. and *Note `SELECT':
select. statements for a `MyISAM' table without locks. That is, you can
insert rows into a `MyISAM' table at the same time other clients are
reading from it. Holes can result from rows having been deleted from or
updated in the middle of the table. If there are holes, concurrent
inserts are disabled but are enabled again automatically when all holes
have been filled with new data. This behavior is altered by the
`concurrent_insert' system variable. See *Note concurrent-inserts::.

If you acquire a table lock explicitly with *Note `LOCK TABLES':
lock-tables, you can request a `READ LOCAL' lock rather than a `READ'
lock to enable other sessions to perform concurrent inserts while you
have the table locked.

To perform many *Note `INSERT': insert. and *Note `SELECT': select.
operations on a table `real_table' when concurrent inserts are not
possible, you can insert rows into a temporary table `temp_table' and
update the real table with the rows from the temporary table
periodically. This can be done with the following code:

     mysql> LOCK TABLES real_table WRITE, temp_table WRITE;
     mysql> INSERT INTO real_table SELECT * FROM temp_table;
     mysql> DELETE FROM temp_table;
     mysql> UNLOCK TABLES;

`InnoDB' uses row locks and `BDB' uses page locks. Deadlocks are
possible for these storage engines because they automatically acquire
locks during the processing of SQL statements, not at the start of the
transaction.

Advantages of row-level locking:

   * Fewer lock conflicts when different sessions access different rows

   * Fewer changes for rollbacks

   * Possible to lock a single row for a long time

Disadvantages of row-level locking:

   * Requires more memory than page-level or table-level locks

   * Slower than page-level or table-level locks when used on a large
     part of the table because you must acquire many more locks

   * Slower than other locks if you often do `GROUP BY' operations on a
     large part of the data or if you must scan the entire table
     frequently

Generally, table locks are superior to page-level or row-level locks in
the following cases:

   * Most statements for the table are reads

   * Statements for the table are a mix of reads and writes, where
     writes are updates or deletes for a single row that can be fetched
     with one key read:

          UPDATE TBL_NAME SET COLUMN=VALUE WHERE UNIQUE_KEY_COL=KEY_VALUE;
          DELETE FROM TBL_NAME WHERE UNIQUE_KEY_COL=KEY_VALUE;

   * *Note `SELECT': select. combined with concurrent *Note `INSERT':
     insert. statements, and very few *Note `UPDATE': update. or *Note
     `DELETE': delete. statements

   * Many scans or `GROUP BY' operations on the entire table without
     any writers

With higher-level locks, you can more easily tune applications by
supporting locks of different types, because the lock overhead is less
than for row-level locks.

Options other than row-level or page-level locking:

   * Versioning (such as that used in MySQL for concurrent inserts)
     where it is possible to have one writer at the same time as many
     readers. This means that the database or table supports different
     views for the data depending on when access begins. Other common
     terms for this are `time travel,' `copy on write,' or `copy on
     demand.'

   * Copy on demand is in many cases superior to page-level or
     row-level locking. However, in the worst case, it can use much
     more memory than using normal locks.

   * Instead of using row-level locks, you can employ application-level
     locks, such as those provided by `GET_LOCK()' and `RELEASE_LOCK()'
     in MySQL.  These are advisory locks, so they work only with
     applications that cooperate with each other. See *Note
     miscellaneous-functions::.


File: manual.info,  Node: table-locking,  Next: concurrent-inserts,  Prev: internal-locking,  Up: locking-issues

8.7.2 Table Locking Issues
--------------------------

To achieve a very high lock speed, MySQL uses table locking (instead of
page, row, or column locking) for all storage engines except `InnoDB',
`BDB', and *Note `NDBCLUSTER': mysql-cluster.

For `InnoDB' and `BDB' tables, MySQL uses table locking only if you
explicitly lock the table with *Note `LOCK TABLES': lock-tables. For
these storage engines, avoid using *Note `LOCK TABLES': lock-tables. at
all, because `InnoDB' uses automatic row-level locking and `BDB' uses
page-level locking to ensure transaction isolation.

For large tables, table locking is often better than row locking, but
there are some disadvantages:

   * Table locking enables many sessions to read from a table at the
     same time, but if a session wants to write to a table, it must
     first get exclusive access. During the update, all other sessions
     that want to access this particular table must wait until the
     update is done.

   * Table locking causes problems in cases such as when a session is
     waiting because the disk is full and free space needs to become
     available before the session can proceed. In this case, all
     sessions that want to access the problem table are also put in a
     waiting state until more disk space is made available.

Table locking is also disadvantageous under the following scenario:

   * A session issues a *Note `SELECT': select.  that takes a long time
     to run.

   * Another session then issues an *Note `UPDATE': update. on the same
     table.  This session waits until the *Note `SELECT': select. is
     finished.

   * Another session issues another *Note `SELECT': select. statement
     on the same table. Because *Note `UPDATE': update. has higher
     priority than *Note `SELECT': select, this *Note `SELECT': select.
     waits for the *Note `UPDATE': update. to finish, _after_ waiting
     for the first *Note `SELECT': select. to finish.

The following items describe some ways to avoid or reduce contention
caused by table locking:

   * Try to get the *Note `SELECT': select.  statements to run faster
     so that they lock tables for a shorter time. You might have to
     create some summary tables to do this.

   * Start *Note `mysqld': mysqld. with `--low-priority-updates'. For
     storage engines that use only table-level locking (such as
     `MyISAM', `MEMORY', and `MERGE'), this gives all statements that
     update (modify) a table lower priority than *Note `SELECT':
     select. statements. In this case, the second *Note `SELECT':
     select.  statement in the preceding scenario would execute before
     the *Note `UPDATE': update. statement, and would not need to wait
     for the first *Note `SELECT': select. to finish.

   * To specify that all updates issued in a specific connection should
     be done with low priority, set the `low_priority_updates' server
     system variable equal to 1.

   * To give a specific *Note `INSERT': insert, *Note `UPDATE': update,
     or *Note `DELETE': delete. statement lower priority, use the
     `LOW_PRIORITY' attribute.

   * To give a specific *Note `SELECT': select.  statement higher
     priority, use the `HIGH_PRIORITY' attribute. See *Note select::.

   * Start *Note `mysqld': mysqld. with a low value for the
     `max_write_lock_count' system variable to force MySQL to
     temporarily elevate the priority of all *Note `SELECT': select.
     statements that are waiting for a table after a specific number of
     inserts to the table occur. This permits `READ' locks after a
     certain number of `WRITE' locks.

   * If you have problems with *Note `INSERT': insert. combined with
     *Note `SELECT': select, consider switching to `MyISAM' tables,
     which support concurrent *Note `SELECT': select. and *Note
     `INSERT': insert. statements. (See *Note concurrent-inserts::.)

   * If you mix inserts and deletes on the same table, *Note `INSERT
     DELAYED': insert-delayed. may be of great help. See *Note
     insert-delayed::.

   * If you have problems with mixed *Note `SELECT': select. and *Note
     `DELETE': delete. statements, the `LIMIT' option to *Note
     `DELETE': delete. may help. See *Note delete::.

   * Using `SQL_BUFFER_RESULT' with *Note `SELECT': select. statements
     can help to make the duration of table locks shorter. See *Note
     select::.

   * You could change the locking code in `mysys/thr_lock.c' to use a
     single queue.  In this case, write locks and read locks would have
     the same priority, which might help some applications.

Here are some tips concerning table locks in MySQL:

   * Concurrent users are not a problem if you do not mix updates with
     selects that need to examine many rows in the same table.

   * You can use *Note `LOCK TABLES': lock-tables. to increase speed,
     because many updates within a single lock is much faster than
     updating without locks. Splitting table contents into separate
     tables may also help.

   * If you encounter speed problems with table locks in MySQL, you may
     be able to improve performance by converting some of your tables
     to `InnoDB' or `BDB' tables. See *Note innodb-storage-engine::, and
     *Note bdb-storage-engine::.


File: manual.info,  Node: concurrent-inserts,  Next: external-locking,  Prev: table-locking,  Up: locking-issues

8.7.3 Concurrent Inserts
------------------------

The `MyISAM' storage engine supports concurrent inserts to reduce
contention between readers and writers for a given table: If a `MyISAM'
table has no holes in the data file (deleted rows in the middle), an
*Note `INSERT': insert. statement can be executed to add rows to the
end of the table at the same time that *Note `SELECT': select.
statements are reading rows from the table. If there are multiple *Note
`INSERT': insert. statements, they are queued and performed in
sequence, concurrently with the *Note `SELECT': select. statements. The
results of a concurrent *Note `INSERT': insert. may not be visible
immediately.

The `concurrent_insert' system variable can be set to modify the
concurrent-insert processing.  By default, the variable is set to 1 and
concurrent inserts are handled as just described. If
`concurrent_insert' is set to 0, concurrent inserts are disabled. If
the variable is set to 2, concurrent inserts at the end of the table
are permitted even for tables that have deleted rows. See also the
description of the `concurrent_insert' system variable.

Under circumstances where concurrent inserts can be used, there is
seldom any need to use the `DELAYED' modifier for *Note `INSERT':
insert. statements.  See *Note insert-delayed::.

If you are using the binary log, concurrent inserts are converted to
normal inserts for `CREATE ...  SELECT' or *Note `INSERT ... SELECT':
insert-select. statements. This is done to ensure that you can
re-create an exact copy of your tables by applying the log during a
backup operation. See *Note binary-log::. In addition, for those
statements a read lock is placed on the selected-from table such that
inserts into that table are blocked. The effect is that concurrent
inserts for that table must wait as well.

With *Note `LOAD DATA INFILE': load-data, if you specify `CONCURRENT'
with a `MyISAM' table that satisfies the condition for concurrent
inserts (that is, it contains no free blocks in the middle), other
sessions can retrieve data from the table while *Note `LOAD DATA':
load-data. is executing. Use of the `CONCURRENT' option affects the
performance of *Note `LOAD DATA': load-data. a bit, even if no other
session is using the table at the same time.

If you specify `HIGH_PRIORITY', it overrides the effect of the
`--low-priority-updates' option if the server was started with that
option. It also causes concurrent inserts not to be used.

For *Note `LOCK TABLE': lock-tables, the difference between `READ
LOCAL' and `READ' is that `READ LOCAL' permits nonconflicting *Note
`INSERT': insert. statements (concurrent inserts) to execute while the
lock is held. However, this cannot be used if you are going to
manipulate the database using processes external to the server while
you hold the lock.


File: manual.info,  Node: external-locking,  Prev: concurrent-inserts,  Up: locking-issues

8.7.4 External Locking
----------------------

External locking is the use of file system locking to manage contention
for *Note `MyISAM': myisam-storage-engine. database tables by multiple
processes. External locking is used in situations where a single
process such as the MySQL server cannot be assumed to be the only
process that requires access to tables. Here are some examples:

   * If you run multiple servers that use the same database directory
     (not recommended), each server must have external locking enabled.

   * If you use *Note `myisamchk': myisamchk. to perform table
     maintenance operations on *Note `MyISAM': myisam-storage-engine.
     tables, you must either ensure that the server is not running, or
     that the server has external locking enabled so that it locks
     table files as necessary to coordinate with *Note `myisamchk':
     myisamchk.  for access to the tables. The same is true for use of
     *Note `myisampack': myisampack. to pack *Note `MyISAM':
     myisam-storage-engine. tables.

     If the server is run with external locking enabled, you can use
     *Note `myisamchk': myisamchk. at any time for read operations such
     a checking tables. In this case, if the server tries to update a
     table that *Note `myisamchk': myisamchk. is using, the server will
     wait for *Note `myisamchk': myisamchk. to finish before it
     continues.

     If you use *Note `myisamchk': myisamchk. for write operations such
     as repairing or optimizing tables, or if you use *Note
     `myisampack': myisampack. to pack tables, you _must_ always ensure
     that the *Note `mysqld': mysqld. server is not using the table. If
     you don't stop *Note `mysqld': mysqld, you should at least do a
     *Note `mysqladmin flush-tables': mysqladmin. before you run *Note
     `myisamchk': myisamchk. Your tables _may become corrupted_ if the
     server and *Note `myisamchk': myisamchk. access the tables
     simultaneously.

With external locking in effect, each process that requires access to a
table acquires a file system lock for the table files before proceeding
to access the table. If all necessary locks cannot be acquired, the
process is blocked from accessing the table until the locks can be
obtained (after the process that currently holds the locks releases
them).

External locking affects server performance because the server must
sometimes wait for other processes before it can access tables.

External locking is unnecessary if you run a single server to access a
given data directory (which is the usual case) and if no other programs
such as *Note `myisamchk': myisamchk. need to modify tables while the
server is running. If you only _read_ tables with other programs,
external locking is not required, although *Note `myisamchk': myisamchk.
might report warnings if the server changes tables while *Note
`myisamchk': myisamchk. is reading them.

With external locking disabled, to use *Note `myisamchk': myisamchk,
you must either stop the server while *Note `myisamchk': myisamchk.
executes or else lock and flush the tables before running *Note
`myisamchk': myisamchk.  (See *Note system-optimization::.) To avoid
this requirement, use the *Note `CHECK TABLE': check-table.  and *Note
`REPAIR TABLE': repair-table. statements to check and repair *Note
`MyISAM': myisam-storage-engine. tables.

For *Note `mysqld': mysqld, external locking is controlled by the value
of the `skip_external_locking' system variable. When this variable is
enabled, external locking is disabled, and vice versa. From MySQL 4.0
on, external locking is disabled by default.

Use of external locking can be controlled at server startup by using
the `--external-locking' or `--skip-external-locking' option.

If you do use external locking option to enable updates to *Note
`MyISAM': myisam-storage-engine. tables from many MySQL processes, you
must ensure that the following conditions are satisfied:

   * You should not use the query cache for queries that use tables
     that are updated by another process.

   * You should not start the server with the `--delay-key-write=ALL'
     option or use the `DELAY_KEY_WRITE=1' table option for any shared
     tables. Otherwise, index corruption can occur.

The easiest way to satisfy these conditions is to always use
`--external-locking' together with `--delay-key-write=OFF' and
`--query-cache-size=0'. (This is not done by default because in many
setups it is useful to have a mixture of the preceding options.)


File: manual.info,  Node: optimizing-database-structure,  Next: optimizing-the-server,  Prev: locking-issues,  Up: optimization

8.8 Optimizing Database Structure
=================================

* Menu:

* data-size::                    Make Your Data as Small as Possible
* table-cache::                  How MySQL Opens and Closes Tables
* creating-many-tables::         Disadvantages of Creating Many Tables in the Same Database
* internal-temporary-tables::    How MySQL Uses Internal Temporary Tables


File: manual.info,  Node: data-size,  Next: table-cache,  Prev: optimizing-database-structure,  Up: optimizing-database-structure

8.8.1 Make Your Data as Small as Possible
-----------------------------------------

Design your tables to minimize their space on the disk. This can result
in huge improvements by reducing the amount of data written to and read
from disk. Smaller tables normally require less main memory while their
contents are being actively processed during query execution. Any space
reduction for table data also results in smaller indexes that can be
processed faster.

MySQL supports many different storage engines (table types) and row
formats. For each table, you can decide which storage and indexing
method to use. Choosing the proper table format for your application
may give you a big performance gain. See *Note storage-engines::.

You can get better performance for a table and minimize storage space
by using the techniques listed here:

   * Use the most efficient (smallest) data types possible. MySQL has
     many specialized types that save disk space and memory.  For
     example, use the smaller integer types if possible to get smaller
     tables. *Note `MEDIUMINT': numeric-types.  is often a better
     choice than *Note `INT': numeric-types. because a *Note
     `MEDIUMINT': numeric-types. column uses 25% less space.

   * Declare columns to be `NOT NULL' if possible. It makes everything
     faster and you save one bit per column. If you really need `NULL'
     in your application, you should definitely use it. Just avoid
     having it on all columns by default.

   * For `MyISAM' tables, if you do not have any variable-length columns
     (*Note `VARCHAR': char, *Note `TEXT': blob, or *Note `BLOB': blob.
     columns), a fixed-size row format is used. This is faster but
     unfortunately may waste some space. See *Note
     myisam-table-formats::. You can hint that you want to have fixed
     length rows even if you have *Note `VARCHAR': char. columns with
     the *Note `CREATE TABLE': create-table. option `ROW_FORMAT=FIXED'.

   * Starting with MySQL 5.0.3, `InnoDB' tables use a more compact
     storage format. In earlier versions of MySQL, `InnoDB' rows
     contain some redundant information, such as the number of columns
     and the length of each column, even for fixed-size columns. By
     default, tables are created in the compact format
     (`ROW_FORMAT=COMPACT'). If you wish to downgrade to older versions
     of MySQL, you can request the old format with
     `ROW_FORMAT=REDUNDANT'.

     The presence of the compact row format decreases row storage space
     by about 20% at the cost of increasing CPU use for some
     operations. If your workload is a typical one that is limited by
     cache hit rates and disk speed it is likely to be faster. If it is
     a rare case that is limited by CPU speed, it might be slower.

     The compact `InnoDB' format also changes how *Note `CHAR': char.
     columns containing UTF-8 data are stored. With
     `ROW_FORMAT=REDUNDANT', a UTF-8 `CHAR(N)' occupies 3 x N bytes,
     given that the maximum length of a UTF-8 encoded character is
     three bytes. Many languages can be written primarily using
     single-byte UTF-8 characters, so a fixed storage length often
     wastes space. With `ROW_FORMAT=COMPACT' format, `InnoDB' allocates
     a variable amount of storage in the range from N to 3 x N bytes
     for these columns by stripping trailing spaces if necessary. The
     minimum storage length is kept as N bytes to facilitate in-place
     updates in typical cases.

   * The primary index of a table should be as short as possible.  This
     makes identification of each row easy and efficient.

   * Create only the indexes that you really need. Indexes are good for
     retrieval but bad when you need to store data quickly. If you
     access a table mostly by searching on a combination of columns,
     create an index on them. The first part of the index should be the
     column most used. If you _always_ use many columns when selecting
     from the table, the first column in the index should be the one
     with the most duplicates to obtain better compression of the index.

   * If it is very likely that a string column has a unique prefix on
     the first number of characters, it is better to index only this
     prefix, using MySQL's support for creating an index on the
     leftmost part of the column (see *Note create-index::). Shorter
     indexes are faster, not only because they require less disk space,
     but because they also give you more hits in the index cache, and
     thus fewer disk seeks. See *Note server-parameters::.

   * In some circumstances, it can be beneficial to split into two a
     table that is scanned very often. This is especially true if it is
     a dynamic-format table and it is possible to use a smaller static
     format table that can be used to find the relevant rows when
     scanning the table.


File: manual.info,  Node: table-cache,  Next: creating-many-tables,  Prev: data-size,  Up: optimizing-database-structure

8.8.2 How MySQL Opens and Closes Tables
---------------------------------------

When you execute a *Note `mysqladmin status': mysqladmin. command, you
should see something like this:

     Uptime: 426 Running threads: 1 Questions: 11082
     Reloads: 1 Open tables: 12

The `Open tables' value of 12 can be somewhat puzzling if you have only
six tables.

MySQL is multi-threaded, so there may be many clients issuing queries
for a given table simultaneously. To minimize the problem with multiple
client sessions having different states on the same table, the table is
opened independently by each concurrent session. This uses additional
memory but normally increases performance. With `MyISAM' tables, one
extra file descriptor is required for the data file for each client
that has the table open. (By contrast, the index file descriptor is
shared between all sessions.)

The `table_cache' and `max_connections' system variables affect the
maximum number of files the server keeps open. If you increase one or
both of these values, you may run up against a limit imposed by your
operating system on the per-process number of open file descriptors.
Many operating systems permit you to increase the open-files limit,
although the method varies widely from system to system. Consult your
operating system documentation to determine whether it is possible to
increase the limit and how to do so.

`table_cache' is related to `max_connections'. For example, for 200
concurrent running connections, you should have a table cache size of
at least `200 * N', where N is the maximum number of tables per join in
any of the queries which you execute. You must also reserve some extra
file descriptors for temporary tables and files.

Make sure that your operating system can handle the number of open file
descriptors implied by the `table_cache' setting. If `table_cache' is
set too high, MySQL may run out of file descriptors and refuse
connections, fail to perform queries, and be very unreliable. You also
have to take into account that the `MyISAM' storage engine needs two
file descriptors for each unique open table.  You can increase the
number of file descriptors available to MySQL using the
`--open-files-limit' startup option to *Note `mysqld': mysqld. See
*Note not-enough-file-handles::.

The cache of open tables is kept at a level of `table_cache' entries.
The default value is 64; this can be changed with the `--table_cache'
option to *Note `mysqld': mysqld. Note that MySQL may temporarily open
more tables than this to execute queries.

MySQL closes an unused table and removes it from the table cache under
the following circumstances:

   * When the cache is full and a thread tries to open a table that is
     not in the cache.

   * When the cache contains more than `table_cache' entries and a
     table in the cache is no longer being used by any threads.

   * When a table flushing operation occurs. This happens when someone
     issues a *Note `FLUSH TABLES': flush. statement or executes a
     *Note `mysqladmin flush-tables': mysqladmin. or *Note `mysqladmin
     refresh': mysqladmin. command.

When the table cache fills up, the server uses the following procedure
to locate a cache entry to use:

   * Tables that are not currently in use are released, beginning with
     the table least recently used.

   * If a new table needs to be opened, but the cache is full and no
     tables can be released, the cache is temporarily extended as
     necessary. When the cache is in a temporarily extended state and a
     table goes from a used to unused state, the table is closed and
     released from the cache.

A `MyISAM' table is opened for each concurrent access. This means the
table needs to be opened twice if two threads access the same table or
if a thread accesses the table twice in the same query (for example, by
joining the table to itself). Each concurrent open requires an entry in
the table cache. The first open of any `MyISAM' table takes two file
descriptors: one for the data file and one for the index file. Each
additional use of the table takes only one file descriptor for the data
file. The index file descriptor is shared among all threads.

If you are opening a table with the `HANDLER TBL_NAME OPEN' statement, a
dedicated table object is allocated for the thread. This table object
is not shared by other threads and is not closed until the thread calls
`HANDLER TBL_NAME CLOSE' or the thread terminates. When this happens,
the table is put back in the table cache (if the cache is not full). See
*Note handler::.

You can determine whether your table cache is too small by checking the
*Note `mysqld': mysqld. status variable `Opened_tables', which indicates
the number of table-opening operations since the server started:

     mysql> SHOW GLOBAL STATUS LIKE 'Opened_tables';
     +---------------+-------+
     | Variable_name | Value |
     +---------------+-------+
     | Opened_tables | 2741  |
     +---------------+-------+

If the value is very large or increases rapidly, even when you have not
issued many *Note `FLUSH TABLES': flush.  statements, you should
increase the table cache size. See *Note server-system-variables::, and
*Note server-status-variables::.


File: manual.info,  Node: creating-many-tables,  Next: internal-temporary-tables,  Prev: table-cache,  Up: optimizing-database-structure

8.8.3 Disadvantages of Creating Many Tables in the Same Database
----------------------------------------------------------------

If you have many `MyISAM' tables in the same database directory, open,
close, and create operations are slow.  If you execute *Note `SELECT':
select. statements on many different tables, there is a little overhead
when the table cache is full, because for every table that has to be
opened, another must be closed. You can reduce this overhead by
increasing the number of entries permitted in the table cache.


File: manual.info,  Node: internal-temporary-tables,  Prev: creating-many-tables,  Up: optimizing-database-structure

8.8.4 How MySQL Uses Internal Temporary Tables
----------------------------------------------

In some cases, the server creates internal temporary tables while
processing queries. Such a table can be held in memory and processed by
the `MEMORY' storage engine, or stored on disk and processed by the
`MyISAM' storage engine. The server may create a temporary table
initially as an in-memory table, then convert it to an on-disk table if
it becomes too large. Users have no direct control over when the server
creates an internal temporary table or which storage engine the server
uses to manage it.

Temporary tables can be created under conditions such as these:

   * If there is an `ORDER BY' clause and a different `GROUP BY'
     clause, or if the `ORDER BY' or `GROUP BY' contains columns from
     tables other than the first table in the join queue, a temporary
     table is created.

   * `DISTINCT' combined with `ORDER BY' may require a temporary table.

   * If you use the `SQL_SMALL_RESULT' option, MySQL uses an in-memory
     temporary table, unless the query also contains elements
     (described later) that require on-disk storage.

To determine whether a query requires a temporary table, use *Note
`EXPLAIN': explain. and check the `Extra' column to see whether it says
`Using temporary'. See *Note using-explain::.

Some conditions prevent the use of an in-memory temporary table, in
which case the server uses an on-disk table instead:

   * Presence of a *Note `BLOB': blob. or *Note `TEXT': blob. column in
     the table

   * Presence of any column in a `GROUP BY' or `DISTINCT' clause larger
     than 512 bytes

   * Presence of any column larger than 512 bytes in the *Note
     `SELECT': select. list, if *Note `UNION': union. or *Note `UNION
     ALL': union.  is used

The *Note `SHOW COLUMNS': show-columns. and The *Note `DESCRIBE':
describe. statements use `BLOB' as the type for some columns, thus the
temporary table used for the results is an on-disk table.

If an internal temporary table is created initially as an in-memory
table but becomes too large, MySQL automatically converts it to an
on-disk table. The maximum size for in-memory temporary tables is the
minimum of the `tmp_table_size' and `max_heap_table_size' values.  This
differs from `MEMORY' tables explicitly created with *Note `CREATE
TABLE': create-table.: For such tables, the `max_heap_table_size' system
variable determines how large the table is permitted to grow and there
is no conversion to on-disk format.

When the server creates an internal temporary table (either in memory
or on disk), it increments the `Created_tmp_tables' status variable. If
the server creates the table on disk (either initially or by converting
an in-memory table) it increments the `Created_tmp_disk_tables' status
variable.


File: manual.info,  Node: optimizing-the-server,  Next: thread-information,  Prev: optimizing-database-structure,  Up: optimization

8.9 Optimizing the MySQL Server
===============================

* Menu:

* system-optimization::          System Factors and Startup Parameter Tuning
* server-parameters::            Tuning Server Parameters
* connection-threads::           How MySQL Uses Threads for Client Connections
* memory-use::                   How MySQL Uses Memory
* disk-issues::                  Disk Issues
* symbolic-links::               Using Symbolic Links
* large-page-support::           Enabling Large Page Support
* dns::                          How MySQL Uses DNS


File: manual.info,  Node: system-optimization,  Next: server-parameters,  Prev: optimizing-the-server,  Up: optimizing-the-server

8.9.1 System Factors and Startup Parameter Tuning
-------------------------------------------------

We start with system-level factors, because some of these decisions
must be made very early to achieve large performance gains. In other
cases, a quick look at this section may suffice.  However, it is always
nice to have a sense of how much can be gained by changing factors that
apply at this level.

The operating system to use is very important. To get the best use of
multiple-CPU machines, you should use Solaris (because its threads
implementation works well) or Linux (because the 2.4 and later kernels
have good SMP support). Note that older Linux kernels have a 2GB
filesize limit by default. If you have such a kernel and a need for
files larger than 2GB, you should get the Large File Support (LFS)
patch for the ext2 file system. Other file systems such as ReiserFS and
XFS do not have this 2GB limitation.

Before using MySQL in production, we advise you to test it on your
intended platform.

Other tips:

   * If you have enough RAM, you could remove all swap devices.  Some
     operating systems use a swap device in some contexts even if you
     have free memory.

   * Avoid external locking for *Note `MyISAM': myisam-storage-engine.
     tables. Since MySQL 4.0, the default has been for external locking
     to be disabled on all systems. The `--external-locking' and
     `--skip-external-locking' options explicitly enable and disable
     external locking.

     Note that disabling external locking does not affect MySQL's
     functionality as long as you run only one server. Just remember to
     take down the server (or lock and flush the relevant tables)
     before you run *Note `myisamchk': myisamchk. On some systems it is
     mandatory to disable external locking because it does not work,
     anyway.

     The only case in which you cannot disable external locking is when
     you run multiple MySQL _servers_ (not clients) on the same data,
     or if you run *Note `myisamchk': myisamchk. to check (not repair)
     a table without telling the server to flush and lock the tables
     first. Note that using multiple MySQL servers to access the same
     data concurrently is generally _not_ recommended, except when
     using MySQL Cluster.

     The *Note `LOCK TABLES': lock-tables. and *Note `UNLOCK TABLES':
     lock-tables. statements use internal locking, so you can use them
     even if external locking is disabled.


File: manual.info,  Node: server-parameters,  Next: connection-threads,  Prev: system-optimization,  Up: optimizing-the-server

8.9.2 Tuning Server Parameters
------------------------------

You can determine the default buffer sizes used by the *Note `mysqld':
mysqld. server using this command:

     shell> mysqld --verbose --help

This command produces a list of all *Note `mysqld': mysqld.  options
and configurable system variables. The output includes the default
variable values and looks something like this:

     help                              TRUE
     abort-slave-event-count           0
     allow-suspicious-udfs             FALSE
     auto-increment-increment          1
     auto-increment-offset             1
     automatic-sp-privileges           TRUE
     basedir                           /home/jon/bin/mysql-5.0/
     bdb                               FALSE
     bind-address                      (No default value)
     character-set-client-handshake    TRUE
     character-set-filesystem          binary
     character-set-server              latin1
     character-sets-dir                /home/jon/bin/mysql-5.0/share/mysql/charsets/
     chroot                            (No default value)
     collation-server                  latin1_swedish_ci
     completion-type                   0
     concurrent-insert                 1
     console                           FALSE
     datadir                           /home/jon/bin/mysql-5.0/var/
     default-character-set             latin1
     default-collation                 latin1_swedish_ci
     default-time-zone                 (No default value)
     disconnect-slave-event-count      0
     enable-locking                    FALSE
     enable-pstack                     FALSE
     engine-condition-pushdown         FALSE
     external-locking                  FALSE
     federated                         TRUE
     gdb                               FALSE
     large-pages                       FALSE
     init-connect                      (No default value)
     init-file                         (No default value)
     init-slave                        (No default value)
     innodb                            TRUE
     innodb_checksums                  TRUE
     innodb_data_home_dir              (No default value)
     innodb_adaptive_hash_index        TRUE
     innodb_doublewrite                TRUE
     innodb_fast_shutdown              1
     innodb_file_per_table             FALSE
     innodb_flush_log_at_trx_commit    1
     innodb_flush_method               (No default value)
     innodb_locks_unsafe_for_binlog    FALSE
     innodb_log_arch_dir               (No default value)
     innodb_log_group_home_dir         (No default value)
     innodb_max_dirty_pages_pct        90
     innodb_max_purge_lag              0
     innodb_rollback_on_timeout        FALSE
     innodb_status_file                FALSE
     innodb_support_xa                 TRUE
     innodb_table_locks                TRUE
     isam                              FALSE
     language                          /home/jon/bin/mysql-5.0/share/mysql/english/
     lc-time-names                     en_US
     local-infile                      TRUE
     log                               (No default value)
     log-bin                           (No default value)
     log-bin-index                     (No default value)
     log-bin-trust-function-creators   FALSE
     log-bin-trust-routine-creators    FALSE
     log-error
     log-isam                          myisam.log
     log-queries-not-using-indexes     FALSE
     log-short-format                  FALSE
     log-slave-updates                 FALSE
     log-slow-admin-statements         FALSE
     log-slow-queries                  (No default value)
     log-tc                            tc.log
     log-tc-size                       24576
     log-update                        (No default value)
     log-warnings                      1
     low-priority-updates              FALSE
     master-connect-retry              60
     master-host                       (No default value)
     master-info-file                  master.info
     master-password                   (No default value)
     master-port                       3306
     master-retry-count                86400
     master-ssl                        FALSE
     master-ssl-ca                     (No default value)
     master-ssl-capath                 (No default value)
     master-ssl-cert                   (No default value)
     master-ssl-cipher                 (No default value)
     master-ssl-key                    (No default value)
     master-user                       test
     max-binlog-dump-events            0
     memlock                           FALSE
     merge                             TRUE
     myisam-recover                    OFF
     ndbcluster                        FALSE
     new                               FALSE
     old-passwords                     FALSE
     old-style-user-limits             FALSE
     pid-file                          /home/jon/bin/mysql-5.0/var/tonfisk.pid
     port                              3306
     port-open-timeout                 0
     relay-log                         (No default value)
     relay-log-index                   (No default value)
     relay-log-info-file               relay-log.info
     replicate-same-server-id          FALSE
     report-host                       (No default value)
     report-password                   (No default value)
     report-port                       3306
     report-user                       (No default value)
     rpl-recovery-rank                 0
     safe-user-create                  FALSE
     secure-auth                       FALSE
     secure-file-priv                  (No default value)
     server-id                         0
     show-slave-auth-info              FALSE
     skip-grant-tables                 FALSE
     skip-slave-start                  FALSE
     slave-load-tmpdir                 /tmp/
     socket                            /tmp/mysql.sock
     sporadic-binlog-dump-fail         FALSE
     sql-mode                          OFF
     symbolic-links                    TRUE
     sysdate-is-now                    FALSE
     tc-heuristic-recover              (No default value)
     temp-pool                         TRUE
     timed_mutexes                     FALSE
     tmpdir                            (No default value)
     use-symbolic-links                TRUE
     verbose                           TRUE
     warnings                          1
     back_log                          50
     binlog_cache_size                 32768
     bulk_insert_buffer_size           8388608
     connect_timeout                   10
     date_format                       (No default value)
     datetime_format                   (No default value)
     default_week_format               0
     delayed_insert_limit              100
     delayed_insert_timeout            300
     delayed_queue_size                1000
     div_precision_increment           4
     expire_logs_days                  0
     flush_time                        0
     ft_max_word_len                   84
     ft_min_word_len                   4
     ft_query_expansion_limit          20
     ft_stopword_file                  (No default value)
     group_concat_max_len              1024
     innodb_additional_mem_pool_size   1048576
     innodb_autoextend_increment       8
     innodb_buffer_pool_awe_mem_mb     0
     innodb_buffer_pool_size           8388608
     innodb_commit_concurrency         0
     innodb_concurrency_tickets        500
     innodb_file_io_threads            4
     innodb_force_recovery             0
     innodb_lock_wait_timeout          50
     innodb_log_buffer_size            1048576
     innodb_log_file_size              5242880
     innodb_log_files_in_group         2
     innodb_mirrored_log_groups        1
     innodb_open_files                 300
     innodb_sync_spin_loops            20
     innodb_thread_concurrency         8
     innodb_thread_sleep_delay         10000
     interactive_timeout               28800
     join_buffer_size                  131072
     keep_files_on_create              FALSE
     key_buffer_size                   8384512
     key_cache_age_threshold           300
     key_cache_block_size              1024
     key_cache_division_limit          100
     long_query_time                   10
     lower_case_table_names            0
     max_allowed_packet                1048576
     max_binlog_cache_size             18446744073709547520
     max_binlog_size                   1073741824
     max_connect_errors                10
     max_connections                   100
     max_delayed_threads               20
     max_error_count                   64
     max_heap_table_size               16777216
     max_join_size                     18446744073709551615
     max_length_for_sort_data          1024
     max_prepared_stmt_count           16382
     max_relay_log_size                0
     max_seeks_for_key                 18446744073709551615
     max_sort_length                   1024
     max_sp_recursion_depth            0
     max_tmp_tables                    32
     max_user_connections              0
     max_write_lock_count              18446744073709551615
     multi_range_count                 256
     myisam_block_size                 1024
     myisam_data_pointer_size          6
     myisam_max_extra_sort_file_size   2147483648
     myisam_max_sort_file_size         9223372036853727232
     myisam_repair_threads             1
     myisam_sort_buffer_size           8388608
     myisam_stats_method               nulls_unequal
     net_buffer_length                 16384
     net_read_timeout                  30
     net_retry_count                   10
     net_write_timeout                 60
     open_files_limit                  0
     optimizer_prune_level             1
     optimizer_search_depth            62
     plugin_dir
     preload_buffer_size               32768
     query_alloc_block_size            8192
     query_cache_limit                 1048576
     query_cache_min_res_unit          4096
     query_cache_size                  0
     query_cache_type                  1
     query_cache_wlock_invalidate      FALSE
     query_prealloc_size               8192
     range_alloc_block_size            4096
     read_buffer_size                  131072
     read_only                         FALSE
     read_rnd_buffer_size              262144
     record_buffer                     131072
     relay_log_purge                   TRUE
     relay_log_space_limit             0
     slave_compressed_protocol         FALSE
     slave_net_timeout                 3600
     slave_transaction_retries         10
     slow_launch_time                  2
     sort_buffer_size                  2097144
     sync-binlog                       0
     sync-frm                          TRUE
     table_cache                       64
     table_lock_wait_timeout           50
     thread_cache_size                 0
     thread_concurrency                10
     thread_stack                      262144
     time_format                       (No default value)
     tmp_table_size                    33554432
     transaction_alloc_block_size      8192
     transaction_prealloc_size         4096
     updatable_views_with_limit        1
     wait_timeout                      28800

For a *Note `mysqld': mysqld. server that is currently running, you can
see the current values of its system variables by connecting to it and
issuing this statement:

     mysql> SHOW VARIABLES;

You can also see some statistical and status indicators for a running
server by issuing this statement:

     mysql> SHOW STATUS;

System variable and status information also can be obtained using *Note
`mysqladmin': mysqladmin.:

     shell> mysqladmin variables
     shell> mysqladmin extended-status

For a full description of all system and status variables, see *Note
server-system-variables::, and *Note server-status-variables::.

MySQL uses algorithms that are very scalable, so you can usually run
with very little memory. However, normally you get better performance
by giving MySQL more memory.

When tuning a MySQL server, the two most important variables to
configure are `key_buffer_size' and `table_cache'. You should first
feel confident that you have these set appropriately before trying to
change any other variables.

The following examples indicate some typical variable values for
different runtime configurations.

   * If you have at least 256MB of memory and many tables and want
     maximum performance with a moderate number of clients, you should
     use something like this:

          shell> mysqld_safe --key_buffer_size=64M --table_cache=256 \
                     --sort_buffer_size=4M --read_buffer_size=1M &

   * If you have only 128MB of memory and only a few tables, but you
     still do a lot of sorting, you can use something like this:

          shell> mysqld_safe --key_buffer_size=16M --sort_buffer_size=1M

     If there are very many simultaneous connections, swapping problems
     may occur unless *Note `mysqld': mysqld. has been configured to
     use very little memory for each connection.  *Note `mysqld':
     mysqld. performs better if you have enough memory for all
     connections.

   * With little memory and lots of connections, use something like
     this:

          shell> mysqld_safe --key_buffer_size=512K --sort_buffer_size=100K \
                     --read_buffer_size=100K &

     Or even this:

          shell> mysqld_safe --key_buffer_size=512K --sort_buffer_size=16K \
                     --table_cache=32 --read_buffer_size=8K \
                     --net_buffer_length=1K &

If you are performing `GROUP BY' or `ORDER BY' operations on tables
that are much larger than your available memory, you should increase
the value of `read_rnd_buffer_size' to speed up the reading of rows
following sorting operations.

You can make use of the example option files included with your MySQL
distribution; see *Note option-files-preconfigured::.

If you specify an option on the command line for *Note `mysqld':
mysqld. or *Note `mysqld_safe': mysqld-safe, it remains in effect only
for that invocation of the server. To use the option every time the
server runs, put it in an option file.

To see the effects of a parameter change, do something like this:

     shell> mysqld --key_buffer_size=32M --verbose --help

The variable values are listed near the end of the output. Make sure
that the `--verbose' and `--help' options are last.  Otherwise, the
effect of any options listed after them on the command line are not
reflected in the output.

For information on tuning the `InnoDB' storage engine, see *Note
innodb-tuning::.


File: manual.info,  Node: connection-threads,  Next: memory-use,  Prev: server-parameters,  Up: optimizing-the-server

8.9.3 How MySQL Uses Threads for Client Connections
---------------------------------------------------

Connection manager threads handle client connection requests on the
network interfaces that the server listens to. On all platforms, one
manager thread handles TCP/IP connection requests. On Unix, this
manager thread also handles Unix socket file connection requests. On
Windows, a manager thread handles shared-memory connection requests,
and another handles named-pipe connection requests. The server does not
create threads to handle interfaces that it does not listen to. For
example, a Windows server that does not have support for named-pipe
connections enabled does not create a thread to handle them.

Connection manager threads associate each client connection with a
thread dedicated to it that handles authentication and request
processing for that connection. Manager threads create a new thread
when necessary but try to avoid doing so by consulting the thread cache
first to see whether it contains a thread that can be used for the
connection. When a connection ends, its thread is returned to the
thread cache if the cache is not full.

In this connection thread model, there are as many threads as there are
clients currently connected, which has some disadvantages when server
workload must scale to handle large numbers of connections. For
example, thread creation and disposal becomes expensive. Also, each
thread requires server and kernel resources, such as stack space. To
accommodate a large number of simultaneous connections, the stack size
per thread must be kept small, leading to a situation where it is
either too small or the server consumes large amounts of memory.
Exhaustion of other resources can occur as well, and scheduling
overhead can become significant.

To control and monitor how the server manages threads that handle
client connections, several system and status variables are relevant.
(See *Note server-system-variables::, and *Note
server-status-variables::.)

The thread cache has a size determined by the `thread_cache_size' system
variable. The default value is 0 (no caching), which causes a thread to
be set up for each new connection and disposed of when the connection
terminates. Set `thread_cache_size' to N to enable N inactive
connection threads to be cached. `thread_cache_size' can be set at
server startup or changed while the server runs. A connection thread
becomes inactive when the client connection with which it was
associated terminates.

To monitor the number of threads in the cache and how many threads have
been created because a thread could not be taken from the cache,
monitor the `Threads_cached' and `Threads_created' status variables.

You can set `max_connections' at server startup or at runtime to
control the maximum number of clients that can connect simultaneously.

When the thread stack is too small, this limits the complexity of the
SQL statements which the server can handle, the recursion depth of
stored procedures, and other memory-consuming actions.  To set a stack
size of N bytes for each thread, start the server with
`--thread_stack=N'.


File: manual.info,  Node: memory-use,  Next: disk-issues,  Prev: connection-threads,  Up: optimizing-the-server

8.9.4 How MySQL Uses Memory
---------------------------

The following list indicates some of the ways that the *Note `mysqld':
mysqld. server uses memory. Where applicable, the name of the system
variable relevant to the memory use is given:

   * All threads share the *Note `MyISAM': myisam-storage-engine.  key
     buffer; its size is determined by the `key_buffer_size' variable.
     Other buffers used by the server are allocated as needed.  See
     *Note server-parameters::.

   * Each thread that is used to manage client connections uses some
     thread-specific space. The following list indicates these and
     which variables control their size:

        * A stack (variable `thread_stack')

        * A connection buffer (variable `net_buffer_length')

        * A result buffer (variable `net_buffer_length')

     The connection buffer and result buffer each begin with a size
     equal to `net_buffer_length' bytes, but are dynamically enlarged
     up to `max_allowed_packet' bytes as needed. The result buffer
     shrinks to `net_buffer_length' bytes after each SQL statement.
     While a statement is running, a copy of the current statement
     string is also allocated.

   * All threads share the same base memory.

   * When a thread is no longer needed, the memory allocated to it is
     released and returned to the system unless the thread goes back
     into the thread cache. In that case, the memory remains allocated.

   * Only compressed `MyISAM' tables are memory mapped. This is because
     the 32-bit memory space of 4GB is not large enough for most big
     tables. When systems with a 64-bit address space become more
     common, we may add general support for memory mapping.

   * Each request that performs a sequential scan of a table allocates
     a _read buffer_ (variable `read_buffer_size').

   * When reading rows in an arbitrary sequence (for example, following
     a sort), a _random-read buffer_ (variable `read_rnd_buffer_size')
     may be allocated to avoid disk seeks.

   * All joins are executed in a single pass, and most joins can be
     done without even using a temporary table. Most temporary tables
     are memory-based hash tables. Temporary tables with a large row
     length (calculated as the sum of all column lengths) or that
     contain *Note `BLOB': blob.  columns are stored on disk.

     If an internal in-memory temporary table becomes too large, MySQL
     handles this automatically by changing the table from in-memory to
     on-disk format, to be handled by the `MyISAM' storage engine. You
     can increase the permissible temporary table size as described in
     *Note internal-temporary-tables::.

   * Most requests that perform a sort allocate a sort buffer and zero
     to two temporary files depending on the result set size. See *Note
     temporary-files::.

   * Almost all parsing and calculating is done in thread-local and
     reusable memory pools. No memory overhead is needed for small
     items, so the normal slow memory allocation and freeing is
     avoided. Memory is allocated only for unexpectedly large strings.

   * For each `MyISAM' table that is opened, the index file is opened
     once; the data file is opened once for each concurrently running
     thread. For each concurrent thread, a table structure, column
     structures for each column, and a buffer of size `3 * N' are
     allocated (where N is the maximum row length, not counting *Note
     `BLOB': blob. columns). A *Note `BLOB': blob. column requires five
     to eight bytes plus the length of the *Note `BLOB': blob. data. The
     `MyISAM' storage engine maintains one extra row buffer for
     internal use.

   * For each table having *Note `BLOB': blob.  columns, a buffer is
     enlarged dynamically to read in larger *Note `BLOB': blob. values.
     If you scan a table, a buffer as large as the largest *Note
     `BLOB': blob. value is allocated.

   * Handler structures for all in-use tables are saved in a cache and
     managed as a FIFO. The initial cache size is taken from the value
     of the `table_cache' system variable. If a table has been used by
     two running threads at the same time, the cache contains two
     entries for the table.  See *Note table-cache::.

   * A *Note `FLUSH TABLES': flush. statement or *Note `mysqladmin
     flush-tables': mysqladmin. command closes all tables that are not
     in use at once and marks all in-use tables to be closed when the
     currently executing thread finishes. This effectively frees most
     in-use memory.  *Note `FLUSH TABLES': flush. does not return until
     all tables have been closed.

   * The server caches information in memory as a result of *Note
     `GRANT': grant. and *Note `CREATE USER': create-user. statements.
     This memory is not released by the corresponding *Note `REVOKE':
     revoke. and *Note `DROP USER': drop-user. statements, so for a
     server that executes many instances of the statements that cause
     caching, there will be an increase in memory use. This cached
     memory can be freed with *Note `FLUSH PRIVILEGES': flush.

`ps' and other system status programs may report that *Note `mysqld':
mysqld. uses a lot of memory. This may be caused by thread stacks on
different memory addresses.  For example, the Solaris version of `ps'
counts the unused memory between stacks as used memory. To verify this,
check available swap with `swap -s'. We test *Note `mysqld': mysqld.
with several memory-leakage detectors (both commercial and Open
Source), so there should be no memory leaks.


File: manual.info,  Node: disk-issues,  Next: symbolic-links,  Prev: memory-use,  Up: optimizing-the-server

8.9.5 Disk Issues
-----------------

   * Disk seeks are a huge performance bottleneck. This problem becomes
     more apparent when the amount of data starts to grow so large that
     effective caching becomes impossible. For large databases where
     you access data more or less randomly, you can be sure that you
     need at least one disk seek to read and a couple of disk seeks to
     write things. To minimize this problem, use disks with low seek
     times.

   * Increase the number of available disk spindles (and thereby reduce
     the seek overhead) by either symlinking files to different disks
     or striping the disks:

        * Using symbolic links

          This means that, for `MyISAM' tables, you symlink the index
          file and data files from their usual location in the data
          directory to another disk (that may also be striped). This
          makes both the seek and read times better, assuming that the
          disk is not used for other purposes as well. See *Note
          symbolic-links::.

        * Striping

          Striping means that you have many disks and put the first
          block on the first disk, the second block on the second disk,
          and the N-th block on the (`N MOD NUMBER_OF_DISKS') disk, and
          so on. This means if your normal data size is less than the
          stripe size (or perfectly aligned), you get much better
          performance. Striping is very dependent on the operating
          system and the stripe size, so benchmark your application
          with different stripe sizes.  See *Note custom-benchmarks::.

          The speed difference for striping is _very_ dependent on the
          parameters.  Depending on how you set the striping parameters
          and number of disks, you may get differences measured in
          orders of magnitude. You have to choose to optimize for
          random or sequential access.

   * For reliability, you may want to use RAID 0+1 (striping plus
     mirroring), but in this case, you need 2 x N drives to hold N
     drives of data. This is probably the best option if you have the
     money for it.  However, you may also have to invest in some
     volume-management software to handle it efficiently.

   * A good option is to vary the RAID level according to how critical
     a type of data is. For example, store semi-important data that can
     be regenerated on a RAID 0 disk, but store really important data
     such as host information and logs on a RAID 0+1 or RAID N disk.
     RAID N can be a problem if you have many writes, due to the time
     required to update the parity bits.

   * On Linux, you can get much better performance by using `hdparm' to
     configure your disk's interface. (Up to 100% under load is not
     uncommon.) The following `hdparm' options should be quite good for
     MySQL, and probably for many other applications:

          hdparm -m 16 -d 1

     Note that performance and reliability when using this command
     depend on your hardware, so we strongly suggest that you test your
     system thoroughly after using `hdparm'. Please consult the
     `hdparm' manual page for more information.  If `hdparm' is not
     used wisely, file system corruption may result, so back up
     everything before experimenting!

   * You can also set the parameters for the file system that the
     database uses:

     If you do not need to know when files were last accessed (which is
     not really useful on a database server), you can mount your file
     systems with the `-o noatime' option. That skips updates to the
     last access time in inodes on the file system, which avoids some
     disk seeks.

     On many operating systems, you can set a file system to be updated
     asynchronously by mounting it with the `-o async' option. If your
     computer is reasonably stable, this should give you better
     performance without sacrificing too much reliability. (This flag
     is on by default on Linux.)


File: manual.info,  Node: symbolic-links,  Next: large-page-support,  Prev: disk-issues,  Up: optimizing-the-server

8.9.6 Using Symbolic Links
--------------------------

* Menu:

* symbolic-links-to-databases::  Using Symbolic Links for Databases on Unix
* symbolic-links-to-tables::     Using Symbolic Links for Tables on Unix
* windows-symbolic-links::       Using Symbolic Links for Databases on Windows

You can move tables and databases from the database directory to other
locations and replace them with symbolic links to the new locations.
You might want to do this, for example, to move a database to a file
system with more free space or increase the speed of your system by
spreading your tables to different disk.

The recommended way to do this is simply to symlink databases to a
different disk. Symlink tables only as a last resort.


File: manual.info,  Node: symbolic-links-to-databases,  Next: symbolic-links-to-tables,  Prev: symbolic-links,  Up: symbolic-links

8.9.6.1 Using Symbolic Links for Databases on Unix
..................................................

On Unix, the way to symlink a database is first to create a directory
on some disk where you have free space and then to create a symlink to
it from the MySQL data directory.

     shell> mkdir /dr1/databases/test
     shell> ln -s /dr1/databases/test /PATH/TO/DATADIR

MySQL does not support linking one directory to multiple databases.
Replacing a database directory with a symbolic link works as long as
you do not make a symbolic link between databases. Suppose that you
have a database `db1' under the MySQL data directory, and then make a
symlink `db2' that points to `db1':

     shell> cd /PATH/TO/DATADIR
     shell> ln -s db1 db2

The result is that, or any table `tbl_a' in `db1', there also appears
to be a table `tbl_a' in `db2'. If one client updates `db1.tbl_a' and
another client updates `db2.tbl_a', problems are likely to occur.

However, if you really need to do this, it is possible by altering the
source file `mysys/my_symlink.c', in which you should look for the
following statement:

     if (!(MyFlags & MY_RESOLVE_LINK) ||
         (!lstat(filename,&stat_buff) && S_ISLNK(stat_buff.st_mode)))

Change the statement to this:

     if (1)


File: manual.info,  Node: symbolic-links-to-tables,  Next: windows-symbolic-links,  Prev: symbolic-links-to-databases,  Up: symbolic-links

8.9.6.2 Using Symbolic Links for Tables on Unix
...............................................

You should not symlink tables on systems that do not have a fully
operational `realpath()' call. (Linux and Solaris support
`realpath()'). You can check whether your system supports symbolic
links by issuing a `SHOW VARIABLES LIKE 'have_symlink'' statement.

Symlinks are fully supported only for `MyISAM' tables. For files used
by tables for other storage engines, you may get strange problems if
you try to use symbolic links.

The handling of symbolic links for `MyISAM' tables works as follows:

   * In the data directory, you always have the table format (`.frm')
     file, the data (`.MYD') file, and the index (`.MYI') file. The
     data file and index file can be moved elsewhere and replaced in
     the data directory by symlinks. The format file cannot.

   * You can symlink the data file and the index file independently to
     different directories.

   * You can instruct a running MySQL server to perform the symlinking
     by using the `DATA DIRECTORY' and `INDEX DIRECTORY' options to
     *Note `CREATE TABLE': create-table. See *Note create-table::.
     Alternatively, symlinking can be accomplished manually from the
     command line using `ln -s' if *Note `mysqld': mysqld. is not
     running.

     *Note*:

     Beginning with MySQL 5.0.60, the path used with either or both of
     the `DATA DIRECTORY' and `INDEX DIRECTORY' options may not include
     the MySQL `data' directory.  (Bug #32167)

   * *Note `myisamchk': myisamchk. does not replace a symlink with the
     data file or index file. It works directly on the file to which
     the symlink points. Any temporary files are created in the
     directory where the data file or index file is located. The same
     is true for the *Note `ALTER TABLE': alter-table, *Note `OPTIMIZE
     TABLE': optimize-table, and *Note `REPAIR TABLE': repair-table.
     statements.

   * *Note*:

     When you drop a table that is using symlinks, _both the symlink
     and the file to which the symlink points are dropped_. This is an
     extremely good reason why you should _not_ run *Note `mysqld':
     mysqld.  as the system `root' or permit system users to have write
     access to MySQL database directories.

   * If you rename a table with `ALTER TABLE ...  RENAME' or *Note
     `RENAME TABLE': rename-table. and you do not move the table to
     another database, the symlinks in the database directory are
     renamed to the new names and the data file and index file are
     renamed accordingly.

   * If you use `ALTER TABLE ... RENAME' or *Note `RENAME TABLE':
     rename-table. to move a table to another database, the table is
     moved to the other database directory. If the table name changed,
     the symlinks in the new database directory are renamed to the new
     names and the data file and index file are renamed accordingly.

   * If you are not using symlinks, you should use the
     `--skip-symbolic-links' option to *Note `mysqld': mysqld. to
     ensure that no one can use *Note `mysqld': mysqld. to drop or
     rename a file outside of the data directory.

Table symlink operations that are not yet supported:

   * *Note `ALTER TABLE': alter-table. ignores the `DATA DIRECTORY' and
     `INDEX DIRECTORY' table options.

   * *Note `BACKUP TABLE': backup-table. and *Note `RESTORE TABLE':
     restore-table. do not respect symbolic links.

   * The `.frm' file must _never_ be a symbolic link (as indicated
     previously, only the data and index files can be symbolic links).
     Attempting to do this (for example, to make synonyms) produces
     incorrect results. Suppose that you have a database `db1' under
     the MySQL data directory, a table `tbl1' in this database, and in
     the `db1' directory you make a symlink `tbl2' that points to
     `tbl1':

          shell> cd /PATH/TO/DATADIR/db1
          shell> ln -s tbl1.frm tbl2.frm
          shell> ln -s tbl1.MYD tbl2.MYD
          shell> ln -s tbl1.MYI tbl2.MYI

     Problems result if one thread reads `db1.tbl1' and another thread
     updates `db1.tbl2':

        * The query cache is `fooled' (it has no way of knowing that
          `tbl1' has not been updated, so it returns outdated results).

        * `ALTER' statements on `tbl2' fail.


File: manual.info,  Node: windows-symbolic-links,  Prev: symbolic-links-to-tables,  Up: symbolic-links

8.9.6.3 Using Symbolic Links for Databases on Windows
.....................................................

Symbolic links are enabled by default for all Windows servers.  This
enables you to put a database directory on a different disk by setting
up a symbolic link to it. This is similar to the way that database
symbolic links work on Unix, although the procedure for setting up the
link is different. If you do not need symbolic links, you can disable
them using the `--skip-symbolic-links' option.

On Windows, create a symbolic link to a MySQL database by creating a
file in the data directory that contains the path to the destination
directory. The file should be named `DB_NAME.sym', where DB_NAME is the
database name.

Suppose that the MySQL data directory is `C:\mysql\data' and you want
to have database `foo' located at `D:\data\foo'. Set up a symlink using
this procedure:

  1. Make sure that the `D:\data\foo' directory exists by creating it
     if necessary. If you already have a database directory named `foo'
     in the data directory, you should move it to `D:\data'. Otherwise,
     the symbolic link will be ineffective. To avoid problems, make
     sure that the server is not running when you move the database
     directory.

  2. Create a text file `C:\mysql\data\foo.sym' that contains the path
     name `D:\data\foo\'.

     *Note*:

     The path name to the new database and tables should be absolute.
     If you specify a relative path, the location will be relative to
     the `foo.sym' file.

After this, all tables created in the database `foo' are created in
`D:\data\foo'.

The following limitations apply to the use of `.sym' files for database
symbolic linking on Windows:

   * The symbolic link is not used if a directory with the same name as
     the database exists in the MySQL data directory.

   * The `--innodb_file_per_table' option cannot be used.

   * If you run *Note `mysqld': mysqld. as a service, you cannot use a
     mapped drive to a remote server as the destination of the symbolic
     link. As a workaround, you can use the full path
     (`\\servername\path\').


File: manual.info,  Node: large-page-support,  Next: dns,  Prev: symbolic-links,  Up: optimizing-the-server

8.9.7 Enabling Large Page Support
---------------------------------

Some hardware/operating system architectures support memory pages
greater than the default (usually 4KB). The actual implementation of
this support depends on the underlying hardware and operating system.
Applications that perform a lot of memory accesses may obtain
performance improvements by using large pages due to reduced
Translation Lookaside Buffer (TLB) misses.

In MySQL, large pages can be used by InnoDB, to allocate memory for its
buffer pool and additional memory pool.

Currently, MySQL supports only the Linux implementation of large page
support (which is called HugeTLB in Linux).

Before large pages can be used on Linux, the kernel must be enabled to
support them and it is necessary to configure the HugeTLB memory pool.
For reference, the HugeTBL API is documented in the
`Documentation/vm/hugetlbpage.txt' file of your Linux sources.

The kernel for some recent systems such as Red Hat Enterprise Linux
appear to have the large pages feature enabled by default.  To check
whether this is true for your kernel, use the following command and
look for output lines containing `huge':

     shell> cat /proc/meminfo | grep -i huge
     HugePages_Total:       0
     HugePages_Free:        0
     HugePages_Rsvd:        0
     HugePages_Surp:        0
     Hugepagesize:       4096 kB

The nonempty command output indicates that large page support is
present, but the zero values indicate that no pages are configured for
use.

If your kernel needs to be reconfigured to support large pages, consult
the `hugetlbpage.txt' file for instructions.

Assuming that your Linux kernel has large page support enabled,
configure it for use by MySQL using the following commands.  Normally,
you put these in an `rc' file or equivalent startup file that is
executed during the system boot sequence, so that the commands execute
each time the system starts. The commands should execute early in the
boot sequence, before the MySQL server starts. Be sure to change the
allocation numbers and the group number as appropriate for your system.

     # Set the number of pages to be used.
     # Each page is normally 2MB, so a value of 20 = 40MB.
     # This command actually allocates memory, so this much
     # memory must be available.
     echo 20 > /proc/sys/vm/nr_hugepages

     # Set the group number that is permitted to access this
     # memory (102 in this case). The mysql user must be a
     # member of this group.
     echo 102 > /proc/sys/vm/hugetlb_shm_group

     # Increase the amount of shmem permitted per segment
     # (12G in this case).
     echo 1560281088 > /proc/sys/kernel/shmmax

     # Increase total amount of shared memory.  The value
     # is the number of pages. At 4KB/page, 4194304 = 16GB.
     echo 4194304 > /proc/sys/kernel/shmall

For MySQL usage, you normally want the value of `shmmax' to be close to
the value of `shmall'.

To verify the large page configuration, check `/proc/meminfo' again as
described previously. Now you should see some nonzero values:

     shell> cat /proc/meminfo | grep -i huge
     HugePages_Total:      20
     HugePages_Free:       20
     HugePages_Rsvd:        0
     HugePages_Surp:        0
     Hugepagesize:       4096 kB

The final step to make use of the `hugetlb_shm_group' is to give the
`mysql' user an `unlimited' value for the memlock limit. This can by
done either by editing `/etc/security/limits.conf' or by adding the
following command to your *Note `mysqld_safe': mysqld-safe. script:

     ulimit -l unlimited

Adding the `ulimit' command to *Note `mysqld_safe': mysqld-safe. causes
the `root' user to set the memlock limit to `unlimited' before
switching to the `mysql' user. (This assumes that *Note `mysqld_safe':
mysqld-safe. is started by `root'.)

Large page support in MySQL is disabled by default. To enable it, start
the server with the `--large-pages' option. For example, you can use
the following lines in your server's `my.cnf' file:

     [mysqld]
     large-pages

With this option, `InnoDB' uses large pages automatically for its
buffer pool and additional memory pool. If `InnoDB' cannot do this, it
falls back to use of traditional memory and writes a warning to the
error log: `Warning: Using conventional memory pool'

To verify that large pages are being used, check `/proc/meminfo' again:

     shell> cat /proc/meminfo | grep -i huge
     HugePages_Total:      20
     HugePages_Free:       20
     HugePages_Rsvd:        2
     HugePages_Surp:        0
     Hugepagesize:       4096 kB


File: manual.info,  Node: dns,  Prev: large-page-support,  Up: optimizing-the-server

8.9.8 How MySQL Uses DNS
------------------------

When a new client connects to *Note `mysqld': mysqld, *Note `mysqld':
mysqld. spawns a new thread to handle the request. This thread first
checks whether the host name is in the host name cache. If not, the
thread attempts to resolve the host name:

   * The thread takes the IP address and resolves it to a host name
     (using `gethostbyaddr()'). It then takes that host name and
     resolves it back to the IP address (using `gethostbyname()') and
     compares to ensure it is the original IP address.

   * If the operating system supports the thread-safe
     `gethostbyaddr_r()' and `gethostbyname_r()' calls, the thread uses
     them to perform host name resolution.

   * If the operating system does not support the thread-safe calls,
     the thread locks a mutex and calls `gethostbyaddr()' and
     `gethostbyname()' instead. In this case, no other thread can
     resolve host names that are not in the host name cache until the
     first thread unlocks the mutex.

You can disable DNS host name lookups by starting *Note `mysqld':
mysqld. with the `--skip-name-resolve' option.  However, in this case,
you can use only IP addresses in the MySQL grant tables.

If you have a very slow DNS and many hosts, you can get more
performance by either disabling DNS lookups with `--skip-name-resolve'
or by increasing the `HOST_CACHE_SIZE' define (default value: 128) and
recompiling *Note `mysqld': mysqld.

You can disable the host name cache by starting the server with the
`--skip-host-cache' option. To clear the host name cache, issue a *Note
`FLUSH HOSTS': flush.  statement or execute the *Note `mysqladmin
flush-hosts': mysqladmin. command.

To disallow TCP/IP connections entirely, start *Note `mysqld': mysqld.
with the `--skip-networking' option.


File: manual.info,  Node: thread-information,  Prev: optimizing-the-server,  Up: optimization

8.10 Examining Thread Information
=================================

* Menu:

* thread-commands::              Thread Command Values
* general-thread-states::        General Thread States
* delayed-insert-thread-states::  Delayed-Insert Thread States
* query-cache-thread-states::    Query Cache Thread States
* master-thread-states::         Replication Master Thread States
* slave-io-thread-states::       Replication Slave I/O Thread States
* slave-sql-thread-states::      Replication Slave SQL Thread States
* slave-connection-thread-states::  Replication Slave Connection Thread States
* mysql-cluster-thread-states::  MySQL Cluster Thread States

When you are attempting to ascertain what your MySQL server is doing,
it can be helpful to examine the process list, which is the set of
threads currently executing within the server. Process list information
is available from these sources:

   * The `SHOW [FULL] PROCESSLIST' statement: *Note show-processlist::

   * The *Note `SHOW PROFILE': show-profile. statement: *Note
     show-profiles::

   * The *Note `mysqladmin processlist': mysqladmin. command: *Note
     mysqladmin::

You can always view information about your own threads. To view
information about threads being executed for other accounts, you must
have the `PROCESS' privilege.

Each process list entry contains several pieces of information:

   * `Id' is the connection identifier for the client associated with
     the thread.

   * `User' and `Host' indicate the account associated with the thread.

   * `db' is the default database for the thread, or `NULL' if none is
     selected.

   * `Command' and `State' indicate what the thread is doing.

     Most states correspond to very quick operations. If a thread stays
     in a given state for many seconds, there might be a problem that
     needs to be investigated.

   * `Time' indicates how long the thread has been in its current
     state. The thread's notion of the current time may be altered in
     some cases: The thread can change the time with *Note `SET
     TIMESTAMP = VALUE': set-option. For a thread running on a slave
     that is processing events from the master, the thread time is set
     to the time found in the events and thus reflects current time on
     the master and not the slave.

   * `Info' contains the text of the statement being executed by the
     thread, or `NULL' if it is not executing one. By default, this
     value contains only the first 100 characters of the statement. To
     see the complete statements, use *Note `SHOW FULL PROCESSLIST':
     show-processlist.

The following sections list the possible `Command' values, and `State'
values grouped by category. The meaning for some of these values is
self-evident. For others, additional description is provided.


File: manual.info,  Node: thread-commands,  Next: general-thread-states,  Prev: thread-information,  Up: thread-information

8.10.1 Thread Command Values
----------------------------

A thread can have any of the following `Command' values:

   * `Binlog Dump'

     This is a thread on a master server for sending binary log
     contents to a slave server.

   * `Change user'

     The thread is executing a change-user operation.

   * `Close stmt'

     The thread is closing a prepared statement.

   * `Connect'

     A replication slave is connected to its master.

   * `Connect Out'

     A replication slave is connecting to its master.

   * `Create DB'

     The thread is executing a create-database operation.

   * `Daemon'

     This thread is internal to the server, not a thread that services
     a client connection.

   * `Debug'

     The thread is generating debugging information.

   * `Delayed insert'

     The thread is a delayed-insert handler.

   * `Drop DB'

     The thread is executing a drop-database operation.

   * `Error'

   * `Execute'

     The thread is executing a prepared statement.

   * `Fetch'

     The thread is fetching the results from executing a prepared
     statement.

   * `Field List'

     The thread is retrieving information for table columns.

   * `Init DB'

     The thread is selecting a default database.

   * `Kill'

     The thread is killing another thread.

   * `Long Data'

     The thread is retrieving long data in the result of executing a
     prepared statement.

   * `Ping'

     The thread is handling a server-ping request.

   * `Prepare'

     The thread is preparing a prepared statement.

   * `Processlist'

     The thread is producing information about server threads.

   * `Query'

     The thread is executing a statement.

   * `Quit'

     The thread is terminating.

   * `Refresh'

     The thread is flushing table, logs, or caches, or resetting status
     variable or replication server information.

   * `Register Slave'

     The thread is registering a slave server.

   * `Reset stmt'

     The thread is resetting a prepared statement.

   * `Set option'

     The thread is setting or resetting a client statement-execution
     option.

   * `Shutdown'

     The thread is shutting down the server.

   * `Sleep'

     The thread is waiting for the client to send a new statement to it.

   * `Statistics'

     The thread is producing server-status information.

   * `Table Dump'

     The thread is sending table contents to a slave server.

   * `Time'

     Unused.


File: manual.info,  Node: general-thread-states,  Next: delayed-insert-thread-states,  Prev: thread-commands,  Up: thread-information

8.10.2 General Thread States
----------------------------

The following list describes thread `State' values that are associated
with general query processing and not more specialized activities such
as replication. Many of these are useful only for finding bugs in the
server.

   * `After create'

     This occurs when the thread creates a table (including internal
     temporary tables), at the end of the function that creates the
     table. This state is used even if the table could not be created
     due to some error.

   * `Analyzing'

     The thread is calculating a `MyISAM' table key distributions (for
     example, for *Note `ANALYZE TABLE': analyze-table.).

   * `checking permissions'

     The thread is checking whether the server has the required
     privileges to execute the statement.

   * `Checking table'

     The thread is performing a table check operation.

   * `cleaning up'

     The thread has processed one command and is preparing to free
     memory and reset certain state variables.

   * `closing tables'

     The thread is flushing the changed table data to disk and closing
     the used tables. This should be a fast operation. If not, you
     should verify that you do not have a full disk and that the disk
     is not in very heavy use.

   * `converting HEAP to MyISAM'

     The thread is converting an internal temporary table from a
     `MEMORY' table to an on-disk `MyISAM' table.

   * `copy to tmp table'

     The thread is processing an *Note `ALTER TABLE': alter-table.
     statement. This state occurs after the table with the new
     structure has been created but before rows are copied into it.

   * `Copying to group table'

     If a statement has different `ORDER BY' and `GROUP BY' criteria,
     the rows are sorted by group and copied to a temporary table.

   * `Copying to tmp table'

     The server is copying to a temporary table in memory.

   * `Copying to tmp table on disk'

     The server is copying to a temporary table on disk. The temporary
     result set has become too large (see *Note
     internal-temporary-tables::). Consequently, the thread is changing
     the temporary table from in-memory to disk-based format to save
     memory.

   * `Creating index'

     The thread is processing `ALTER TABLE ... ENABLE KEYS' for a
     `MyISAM' table.

   * `Creating sort index'

     The thread is processing a *Note `SELECT': select. that is
     resolved using an internal temporary table.

   * `creating table'

     The thread is creating a table. This includes creation of
     temporary tables.

   * `Creating tmp table'

     The thread is creating a temporary table in memory or on disk. If
     the table is created in memory but later is converted to an
     on-disk table, the state during that operation will be `Copying to
     tmp table on disk'.

   * `deleting from main table'

     The server is executing the first part of a multiple-table delete.
     It is deleting only from the first table, and saving columns and
     offsets to be used for deleting from the other (reference) tables.

   * `deleting from reference tables'

     The server is executing the second part of a multiple-table delete
     and deleting the matched rows from the other tables.

   * `discard_or_import_tablespace'

     The thread is processing an `ALTER TABLE ... DISCARD TABLESPACE'
     or `ALTER TABLE ... IMPORT TABLESPACE' statement.

   * `end'

     This occurs at the end but before the cleanup of *Note `ALTER
     TABLE': alter-table, *Note `CREATE VIEW': create-view, *Note
     `DELETE': delete, *Note `INSERT': insert, *Note `SELECT': select,
     or *Note `UPDATE': update. statements.

   * `executing'

     The thread has begun executing a statement.

   * `Execution of init_command'

     The thread is executing statements in the value of the
     `init_command' system variable.

   * `freeing items'

     The thread has executed a command. Some freeing of items done
     during this state involves the query cache. This state is usually
     followed by `cleaning up'.

   * `Flushing tables'

     The thread is executing *Note `FLUSH TABLES': flush. and is
     waiting for all threads to close their tables.

   * `FULLTEXT initialization'

     The server is preparing to perform a natural-language full-text
     search.

   * `init'

     This occurs before the initialization of *Note `ALTER TABLE':
     alter-table, *Note `DELETE': delete, *Note `INSERT': insert, *Note
     `SELECT': select, or *Note `UPDATE': update. statements. Actions
     taken by the server in this state include flushing the binary log,
     the `InnoDB' log, and some query cache cleanup operations.

     For the `end' state, the following operations could be happening:

        * Removing query cache entries after data in a table is changed

        * Writing an event to the binary log

        * Freeing memory buffers, including for blobs

   * `Killed'

     Someone has sent a *Note `KILL': kill.  statement to the thread
     and it should abort next time it checks the kill flag. The flag is
     checked in each major loop in MySQL, but in some cases it might
     still take a short time for the thread to die. If the thread is
     locked by some other thread, the kill takes effect as soon as the
     other thread releases its lock.

   * `Locked'

     The query is locked by another query.

   * `logging slow query'

     The thread is writing a statement to the slow-query log.

   * `NULL'

     This state is used for the *Note `SHOW PROCESSLIST':
     show-processlist. state.

   * `login'

     The initial state for a connection thread until the client has
     been authenticated successfully.

   * `Opening tables', `Opening table'

     The thread is trying to open a table. This is should be very fast
     procedure, unless something prevents opening. For example, an
     *Note `ALTER TABLE': alter-table. or a *Note `LOCK TABLE':
     lock-tables. statement can prevent opening a table until the
     statement is finished. It is also worth checking that your
     `table_cache' value is large enough.

   * `optimizing'

     The server is performing initial optimizations for a query.

   * `preparing'

     This state occurs during query optimization.

   * `Purging old relay logs'

     The thread is removing unneeded relay log files.

   * `query end'

     This state occurs after processing a query but before the `freeing
     items' state.

   * `Reading from net'

     The server is reading a packet from the network.

   * `Removing duplicates'

     The query was using *Note `SELECT DISTINCT': select. in such a way
     that MySQL could not optimize away the distinct operation at an
     early stage.  Because of this, MySQL requires an extra stage to
     remove all duplicated rows before sending the result to the client.

   * `removing tmp table'

     The thread is removing an internal temporary table after
     processing a *Note `SELECT': select.  statement. This state is not
     used if no temporary table was created.

   * `rename'

     The thread is renaming a table.

   * `rename result table'

     The thread is processing an *Note `ALTER TABLE': alter-table.
     statement, has created the new table, and is renaming it to
     replace the original table.

   * `Reopen tables'

     The thread got a lock for the table, but noticed after getting the
     lock that the underlying table structure changed. It has freed the
     lock, closed the table, and is trying to reopen it.

   * `Repair by sorting'

     The repair code is using a sort to create indexes.

   * `Repair done'

     The thread has completed a multi-threaded repair for a `MyISAM'
     table.

   * `Repair with keycache'

     The repair code is using creating keys one by one through the key
     cache. This is much slower than `Repair by sorting'.

   * `Rolling back'

     The thread is rolling back a transaction.

   * `Saving state'

     For `MyISAM' table operations such as repair or analysis, the
     thread is saving the new table state to the `.MYI' file header.
     State includes information such as number of rows, the
     `AUTO_INCREMENT' counter, and key distributions.

   * `Searching rows for update'

     The thread is doing a first phase to find all matching rows before
     updating them. This has to be done if the *Note `UPDATE': update.
     is changing the index that is used to find the involved rows.

   * `Sending data'

     The thread is reading and processing rows for a *Note `SELECT':
     select. statement, and sending data to the client. Because
     operations occurring during this this state tend to perform large
     amounts of disk access (reads), it is often the longest-running
     state over the lifetime of a given query.

   * `setup'

     The thread is beginning an *Note `ALTER TABLE': alter-table.
     operation.

   * `Sorting for group'

     The thread is doing a sort to satisfy a `GROUP BY'.

   * `Sorting for order'

     The thread is doing a sort to satisfy a `ORDER BY'.

   * `Sorting index'

     The thread is sorting index pages for more efficient access during
     a `MyISAM' table optimization operation.

   * `Sorting result'

     For a *Note `SELECT': select. statement, this is similar to
     `Creating sort index', but for nontemporary tables.

   * `statistics'

     The server is calculating statistics to develop a query execution
     plan. If a thread is in this state for a long time, the server is
     probably disk-bound performing other work.

   * `System lock'

     The thread is going to request or is waiting for an internal or
     external system lock for the table. If this state is being caused
     by requests for external locks and you are not using multiple
     *Note `mysqld': mysqld. servers that are accessing the same *Note
     `MyISAM': myisam-storage-engine.  tables, you can disable external
     system locks with the `--skip-external-locking' option. However,
     external locking is disabled by default, so it is likely that this
     option will have no effect. For *Note `SHOW PROFILE':
     show-profile, this state means the thread is requesting the lock
     (not waiting for it).

   * `Table lock'

     The next thread state after `System lock'.  The thread has
     acquired an external lock and is going to request an internal
     table lock.

   * `Updating'

     The thread is searching for rows to update and is updating them.

   * `updating main table'

     The server is executing the first part of a multiple-table update.
     It is updating only the first table, and saving columns and
     offsets to be used for updating the other (reference) tables.

   * `updating reference tables'

     The server is executing the second part of a multiple-table update
     and updating the matched rows from the other tables.

   * `User lock'

     The thread is going to request or is waiting for an advisory lock
     requested with a `GET_LOCK()' call. For *Note `SHOW PROFILE':
     show-profile, this state means the thread is requesting the lock
     (not waiting for it).

   * `Waiting for release of readlock'

     The thread is waiting for a global read lock obtained by another
     thread (with *Note `FLUSH TABLES WITH READ LOCK': flush.) to be
     released.

   * `Waiting for tables', `Waiting for table'

     The thread got a notification that the underlying structure for a
     table has changed and it needs to reopen the table to get the new
     structure. However, to reopen the table, it must wait until all
     other threads have closed the table in question.

     This notification takes place if another thread has used *Note
     `FLUSH TABLES': flush. or one of the following statements on the
     table in question: `FLUSH TABLES TBL_NAME', *Note `ALTER TABLE':
     alter-table, *Note `RENAME TABLE': rename-table, *Note `REPAIR
     TABLE': repair-table, *Note `ANALYZE TABLE': analyze-table, or
     *Note `OPTIMIZE TABLE': optimize-table.

   * `Waiting on cond'

     A generic state in which the thread is waiting for a condition to
     become true. No specific state information is available.

   * `Waiting to get readlock'

     The thread has issued a *Note `FLUSH TABLES WITH READ LOCK':
     flush. statement to obtain a global read lock and is waiting to
     obtain the lock.

   * `Writing to net'

     The server is writing a packet to the network.


File: manual.info,  Node: delayed-insert-thread-states,  Next: query-cache-thread-states,  Prev: general-thread-states,  Up: thread-information

8.10.3 Delayed-Insert Thread States
-----------------------------------

These thread states are associated with processing for `DELAYED'
inserts (see *Note insert-delayed::). Some states are associated with
connection threads that process *Note `INSERT DELAYED': insert-delayed.
statements from clients. Other states are associated with
delayed-insert handler threads that insert the rows. There is a
delayed-insert handler thread for each table for which *Note `INSERT
DELAYED': insert-delayed.  statements are issued.

States associated with a connection thread that processes an *Note
`INSERT DELAYED': insert-delayed. statement from the client:

   * `allocating local table'

     The thread is preparing to feed rows to the delayed-insert handler
     thread.

   * `Creating delayed handler'

     The thread is creating a handler for `DELAYED' inserts.

   * `got handler lock'

     This occurs before the `allocating local table' state and after
     the `waiting for handler lock' state, when the connection thread
     gets access to the delayed-insert handler thread.

   * `got old table'

     This occurs after the `waiting for handler open' state. The
     delayed-insert handler thread has signaled that it has ended its
     initialization phase, which includes opening the table for delayed
     inserts.

   * `storing row into queue'

     The thread is adding a new row to the list of rows that the
     delayed-insert handler thread must insert.

   * `update'

   * `waiting for delay_list'

     This occurs during the initialization phase when the thread is
     trying to find the delayed-insert handler thread for the table,
     and before attempting to gain access to the list of delayed-insert
     threads.

   * `waiting for handler insert'

     An *Note `INSERT DELAYED': insert-delayed. handler has processed
     all pending inserts and is waiting for new ones.

   * `waiting for handler lock'

     This occurs before the `allocating local table' state when the
     connection thread waits for access to the delayed-insert handler
     thread.

   * `waiting for handler open'

     This occurs after the `Creating delayed handler' state and before
     the `got old table' state. The delayed-insert handler thread has
     just been started, and the connection thread is waiting for it to
     initialize.

States associated with a delayed-insert handler thread that inserts the
rows:

   * `insert'

     The state that occurs just before inserting rows into the table.

   * `reschedule'

     After inserting a number of rows, the delayed-insert thread sleeps
     to let other threads do work.

   * `upgrading lock'

     A delayed-insert handler is trying to get a lock for the table to
     insert rows.

   * `Waiting for INSERT'

     A delayed-insert handler is waiting for a connection thread to add
     rows to the queue (see `storing row into queue').


File: manual.info,  Node: query-cache-thread-states,  Next: master-thread-states,  Prev: delayed-insert-thread-states,  Up: thread-information

8.10.4 Query Cache Thread States
--------------------------------

These thread states are associated with the query cache (see *Note
query-cache::).

   * `checking privileges on cached query'

     The server is checking whether the user has privileges to access a
     cached query result.

   * `checking query cache for query'

     The server is checking whether the current query is present in the
     query cache.

   * `invalidating query cache entries'

     Query cache entries are being marked invalid because the
     underlying tables have changed.

   * `sending cached result to client'

     The server is taking the result of a query from the query cache
     and sending it to the client.

   * `storing result in query cache'

     The server is storing the result of a query in the query cache.


File: manual.info,  Node: master-thread-states,  Next: slave-io-thread-states,  Prev: query-cache-thread-states,  Up: thread-information

8.10.5 Replication Master Thread States
---------------------------------------

The following list shows the most common states you may see in the
`State' column for the master's `Binlog Dump' thread. If you see no
`Binlog Dump' threads on a master server, this means that replication
is not running--that is, that no slaves are currently connected.

   * `Sending binlog event to slave'

     Binary logs consist of _events_, where an event is usually an
     update plus some other information. The thread has read an event
     from the binary log and is now sending it to the slave.

   * `Finished reading one binlog; switching to next binlog'

     The thread has finished reading a binary log file and is opening
     the next one to send to the slave.

   * `Has sent all binlog to slave; waiting for binlog to be updated'

     The thread has read all outstanding updates from the binary logs
     and sent them to the slave. The thread is now idle, waiting for
     new events to appear in the binary log resulting from new updates
     occurring on the master.

   * `Waiting to finalize termination'

     A very brief state that occurs as the thread is stopping.


File: manual.info,  Node: slave-io-thread-states,  Next: slave-sql-thread-states,  Prev: master-thread-states,  Up: thread-information

8.10.6 Replication Slave I/O Thread States
------------------------------------------

The following list shows the most common states you see in the `State'
column for a slave server I/O thread.  This state also appears in the
`Slave_IO_State' column displayed by *Note `SHOW SLAVE STATUS':
show-slave-status, so you can get a good view of what is happening by
using that statement.

   * `Waiting for master update'

     The initial state before `Connecting to master'.

   * `Connecting to master'

     The thread is attempting to connect to the master.

   * `Checking master version'

     A state that occurs very briefly, after the connection to the
     master is established.

   * `Registering slave on master'

     A state that occurs very briefly after the connection to the
     master is established.

   * `Requesting binlog dump'

     A state that occurs very briefly, after the connection to the
     master is established. The thread sends to the master a request
     for the contents of its binary logs, starting from the requested
     binary log file name and position.

   * `Waiting to reconnect after a failed binlog dump request'

     If the binary log dump request failed (due to disconnection), the
     thread goes into this state while it sleeps, then tries to
     reconnect periodically. The interval between retries can be
     specified using the *Note `CHANGE MASTER TO': change-master-to.
     statement or the `--master-connect-retry' option.

   * `Reconnecting after a failed binlog dump request'

     The thread is trying to reconnect to the master.

   * `Waiting for master to send event'

     The thread has connected to the master and is waiting for binary
     log events to arrive. This can last for a long time if the master
     is idle. If the wait lasts for `slave_net_timeout' seconds, a
     timeout occurs. At that point, the thread considers the connection
     to be broken and makes an attempt to reconnect.

   * `Queueing master event to the relay log'

     The thread has read an event and is copying it to the relay log so
     that the SQL thread can process it.

   * `Waiting to reconnect after a failed master event read'

     An error occurred while reading (due to disconnection). The thread
     is sleeping for the number of seconds set by the *Note `CHANGE
     MASTER TO': change-master-to. statement or
     `--master-connect-retry' option (default 60) before attempting to
     reconnect.

   * `Reconnecting after a failed master event read'

     The thread is trying to reconnect to the master. When connection
     is established again, the state becomes `Waiting for master to
     send event'.

   * `Waiting for the slave SQL thread to free enough relay log space'

     You are using a nonzero `relay_log_space_limit' value, and the
     relay logs have grown large enough that their combined size
     exceeds this value. The I/O thread is waiting until the SQL thread
     frees enough space by processing relay log contents so that it can
     delete some relay log files.

   * `Waiting for slave mutex on exit'

     A state that occurs briefly as the thread is stopping.


File: manual.info,  Node: slave-sql-thread-states,  Next: slave-connection-thread-states,  Prev: slave-io-thread-states,  Up: thread-information

8.10.7 Replication Slave SQL Thread States
------------------------------------------

The following list shows the most common states you may see in the
`State' column for a slave server SQL thread:

   * `Waiting for the next event in relay log'

     The initial state before `Reading event from the relay log'.

   * `Reading event from the relay log'

     The thread has read an event from the relay log so that the event
     can be processed.

   * `Has read all relay log; waiting for the slave I/O thread to
     update it'

     The thread has processed all events in the relay log files, and is
     now waiting for the I/O thread to write new events to the relay
     log.

   * `Making temp file'

     The thread is executing a *Note `LOAD DATA INFILE': load-data.
     statement and is creating a temporary file containing the data
     from which the slave will read rows.

   * `Waiting for slave mutex on exit'

     A very brief state that occurs as the thread is stopping.

The `State' column for the I/O thread may also show the text of a
statement. This indicates that the thread has read an event from the
relay log, extracted the statement from it, and is executing it.


File: manual.info,  Node: slave-connection-thread-states,  Next: mysql-cluster-thread-states,  Prev: slave-sql-thread-states,  Up: thread-information

8.10.8 Replication Slave Connection Thread States
-------------------------------------------------

These thread states occur on a replication slave but are associated
with connection threads, not with the I/O or SQL threads.

   * `Changing master'

     The thread is processing a *Note `CHANGE MASTER TO':
     change-master-to. statement.

   * `Creating table from master dump'

     The slave is creating a table using the *Note `CREATE TABLE':
     create-table. statement contained in the dump from the master.
     Used for *Note `LOAD TABLE FROM MASTER': load-table-from-master.
     and *Note `LOAD DATA FROM MASTER': load-data-from-master.

   * `Killing slave'

     The thread is processing a `STOP SLAVE' statement.

   * `Opening master dump table'

     This state occurs after `Creating table from master dump'.

   * `Reading master dump table data'

     This state occurs after `Opening master dump table'.

   * `Rebuilding the index on master dump table'

     This state occurs after `Reading master dump table data'.

   * `starting slave'

     The thread is starting the slave threads after processing a
     successful *Note `LOAD DATA FROM MASTER': load-data-from-master.
     load operation.


File: manual.info,  Node: mysql-cluster-thread-states,  Prev: slave-connection-thread-states,  Up: thread-information

8.10.9 MySQL Cluster Thread States
----------------------------------

   * `Committing events to binlog'

   * `Opening mysql.ndb_apply_status'

   * `Processing events'

     The thread is processing events for binary logging.

   * `Processing events from schema table'

     The thread is doing the work of schema replication.

   * `Shutting down'

   * `Syncing ndb table schema operation and binlog'

     This is used to have a correct binary log of schema operations for
     NDB.

   * `Waiting for event from ndbcluster'

     The server is acting as an SQL node in a MySQL Cluster, and is
     connected to a cluster management node.

   * `Waiting for first event from ndbcluster'

   * `Waiting for ndbcluster binlog update to reach current position'

   * `Waiting for ndbcluster to start'

   * `Waiting for schema epoch'

     The thread is waiting for a schema epoch (that is, a global
     checkpoint).


File: manual.info,  Node: language-structure,  Next: globalization,  Prev: optimization,  Up: Top

9 Language Structure
********************

* Menu:

* literals::                     Literal Values
* identifiers::                  Schema Object Names
* reserved-words::               Reserved Words
* user-variables::               User-Defined Variables
* expressions::                  Expression Syntax
* comments::                     Comment Syntax

This chapter discusses the rules for writing the following elements of
SQL statements when using MySQL:

   * Literal values such as strings and numbers

   * Identifiers such as database, table, and column names

   * Reserved words

   * User-defined and system variables

   * Comments


File: manual.info,  Node: literals,  Next: identifiers,  Prev: language-structure,  Up: language-structure

9.1 Literal Values
==================

* Menu:

* string-literals::              String Literals
* number-literals::              Number Literals
* date-and-time-literals::       Date and Time Literals
* hexadecimal-literals::         Hexadecimal Literals
* boolean-literals::             Boolean Literals
* bit-field-literals::           Bit-Field Literals
* null-values::                  `NULL' Values

This section describes how to write literal values in MySQL. These
include strings, numbers, hexadecimal values, boolean values, and
`NULL'. The section also covers the various nuances and `gotchas' that
you may run into when dealing with these basic types in MySQL.


File: manual.info,  Node: string-literals,  Next: number-literals,  Prev: literals,  Up: literals

9.1.1 String Literals
---------------------

A string is a sequence of bytes or characters, enclosed within either
single quote (``''') or double quote (``"'') characters.  Examples:

     'a string'
     "another string"

Quoted strings placed next to each other are concatenated to a single
string. The following lines are equivalent:

     'a string'
     'a' ' ' 'string'

If the `ANSI_QUOTES' SQL mode is enabled, string literals can be quoted
only within single quotation marks because a string quoted within
double quotation marks is interpreted as an identifier.

A _binary string_ is a string of bytes that has no character set or
collation. A _nonbinary string_ is a string of characters that has a
character set and collation. For both types of strings, comparisons are
based on the numeric values of the string unit.  For binary strings,
the unit is the byte. For nonbinary strings the unit is the character
and some character sets support multi-byte characters. Character value
ordering is a function of the string collation.

String literals may have an optional character set introducer and
`COLLATE' clause:

     [_CHARSET_NAME]'STRING' [COLLATE COLLATION_NAME]

Examples:

     SELECT _latin1'STRING';
     SELECT _latin1'STRING' COLLATE latin1_danish_ci;

You can use `N'LITERAL'' (or `n'LITERAL'') to create a string in the
national character set. These statements are equivalent:

     SELECT N'some text';
     SELECT n'some text';
     SELECT _utf8'some text';

For more information about these forms of string syntax, see *Note
charset-literal::, and *Note charset-national::.

Within a string, certain sequences have special meaning unless the
`NO_BACKSLASH_ESCAPES' SQL mode is enabled. Each of these sequences
begins with a backslash (``\''), known as the _escape character_. MySQL
recognizes the escape sequences shown in *Note
character-escape-sequences::. For all other escape sequences, backslash
is ignored. That is, the escaped character is interpreted as if it was
not escaped. For example, ``\x'' is just ``x''. These sequences are case
sensitive. For example, ``\b'' is interpreted as a backspace, but
``\B'' is interpreted as ``B''. Escape processing is done according to
the character set indicated by the `character_set_connection' system
variable. This is true even for strings that are preceded by an
introducer that indicates a different character set, as discussed in
*Note charset-literal::.

*Special Character Escape Sequences*

Escape      Character Represented by Sequence
Sequence    
`\0'        An ASCII NUL (`0x00') character.
`\''        A single quote (``''') character.
`\"'        A double quote (``"'') character.
`\b'        A backspace character.
`\n'        A newline (linefeed) character.
`\r'        A carriage return character.
`\t'        A tab character.
`\Z'        ASCII 26 (Control+Z). See note following the table.
`\\'        A backslash (``\'') character.
`\%'        A ``%'' character. See note following the table.
`\_'        A ``_'' character. See note following the table.

The ASCII 26 character can be encoded as ``\Z'' to enable you to work
around the problem that ASCII 26 stands for END-OF-FILE on Windows.
ASCII 26 within a file causes problems if you try to use `mysql DB_NAME
< FILE_NAME'.

The ``\%'' and ``\_'' sequences are used to search for literal
instances of ``%'' and ``_'' in pattern-matching contexts where they
would otherwise be interpreted as wildcard characters. See the
description of the `LIKE' operator in *Note
string-comparison-functions::. If you use ``\%'' or ``\_'' outside of
pattern-matching contexts, they evaluate to the strings ``\%'' and
``\_'', not to ``%'' and ``_''.

There are several ways to include quote characters within a string:

   * A ``''' inside a string quoted with ``''' may be written as ``''''.

   * A ``"'' inside a string quoted with ``"'' may be written as ``""''.

   * Precede the quote character by an escape character (``\'').

   * A ``''' inside a string quoted with ``"'' needs no special
     treatment and need not be doubled or escaped. In the same way,
     ``"'' inside a string quoted with ``''' needs no special treatment.

The following *Note `SELECT': select. statements demonstrate how
quoting and escaping work:

     mysql> SELECT 'hello', '"hello"', '""hello""', 'hel''lo', '\'hello';
     +-------+---------+-----------+--------+--------+
     | hello | "hello" | ""hello"" | hel'lo | 'hello |
     +-------+---------+-----------+--------+--------+

     mysql> SELECT "hello", "'hello'", "''hello''", "hel""lo", "\"hello";
     +-------+---------+-----------+--------+--------+
     | hello | 'hello' | ''hello'' | hel"lo | "hello |
     +-------+---------+-----------+--------+--------+

     mysql> SELECT 'This\nIs\nFour\nLines';
     +--------------------+
     | This
     Is
     Four
     Lines |
     +--------------------+

     mysql> SELECT 'disappearing\ backslash';
     +------------------------+
     | disappearing backslash |
     +------------------------+

If you want to insert binary data into a string column (such as a *Note
`BLOB': blob. column), you should represent certain characters by
escape sequences. Backslash (``\'') and the quote character used to
quote the string must be escaped. In certain client environments, it
may also be necessary to escape `NUL' or Control+Z. The *Note `mysql':
mysql. client truncates quoted strings containing `NUL' characters if
they are not escaped, and Control+Z may be taken for END-OF-FILE on
Windows if not escaped. For the escape sequences that represent each of
these characters, see *Note character-escape-sequences::.

When writing application programs, any string that might contain any of
these special characters must be properly escaped before the string is
used as a data value in an SQL statement that is sent to the MySQL
server. You can do this in two ways:

   * Process the string with a function that escapes the special
     characters. In a C program, you can use the *Note
     `mysql_real_escape_string()': mysql-real-escape-string. C API
     function to escape characters. See *Note
     mysql-real-escape-string::. Within SQL statements that construct
     other SQL statements, you can use the `QUOTE()' function. The Perl
     DBI interface provides a `quote' method to convert special
     characters to the proper escape sequences. See *Note apis-perl::.
     Other language interfaces may provide a similar capability.

   * As an alternative to explicitly escaping special characters, many
     MySQL APIs provide a placeholder capability that enables you to
     insert special markers into a statement string, and then bind data
     values to them when you issue the statement. In this case, the API
     takes care of escaping special characters in the values for you.


File: manual.info,  Node: number-literals,  Next: date-and-time-literals,  Prev: string-literals,  Up: literals

9.1.2 Number Literals
---------------------

Integers are represented as a sequence of digits. Floats use ``.'' as a
decimal separator.  Either type of number may be preceded by ``-'' or
``+'' to indicate a negative or positive value, respectively

Examples of valid integers:

     1221
     0
     -32

Examples of valid floating-point numbers:

     294.42
     -32032.6809e+10
     148.00

An integer may be used in a floating-point context; it is interpreted
as the equivalent floating-point number.


File: manual.info,  Node: date-and-time-literals,  Next: hexadecimal-literals,  Prev: number-literals,  Up: literals

9.1.3 Date and Time Literals
----------------------------

Date and time values can be represented in several formats, such as
quoted strings or as numbers, depending on the exact type of the value
and other factors. For example, in contexts where MySQL expects a date,
it interprets any of `'2015-07-21'', `'20150721'', and `20150721' as a
date.

This section describes the acceptable formats for date and time
literals. For more information about the temporal data types, such as
the range of permitted values, consult these sections:

   * *Note date-and-time-type-overview::

   * *Note date-and-time-types::

* Standard SQL and ODBC Date and Time Literals *

Standard SQL permits temporal literals to be specified using a type
keyword and a string. The space between the keyword and string is
optional.

     DATE 'STR'
     TIME 'STR'
     TIMESTAMP 'STR'

MySQL recognizes those constructions and also the corresponding ODBC
syntax:

     { d 'STR' }
     { t 'STR' }
     { ts 'STR' }

However, MySQL ignores the type keyword and each of the preceding
constructions produces the string value `'STR'', with a type of *Note
`VARCHAR': char.

* String and Numeric Literals in Date and Time Context *

MySQL recognizes *Note `DATE': datetime. values in these formats:

   * As a string in either `'YYYY-MM-DD'' or `'YY-MM-DD'' format. A
     `relaxed' syntax is permitted: Any punctuation character may be
     used as the delimiter between date parts.  For example,
     `'2012-12-31'', `'2012/12/31'', `'2012^12^31'', and `'2012@12@31''
     are equivalent.

   * As a string with no delimiters in either `'YYYYMMDD'' or `'YYMMDD''
     format, provided that the string makes sense as a date. For
     example, `'20070523'' and `'070523'' are interpreted as
     `'2007-05-23'', but `'071332'' is illegal (it has nonsensical
     month and day parts) and becomes `'0000-00-00''.

   * As a number in either `YYYYMMDD' or `YYMMDD' format, provided that
     the number makes sense as a date. For example, `19830905' and
     `830905' are interpreted as `'1983-09-05''.

MySQL recognizes *Note `DATETIME': datetime. and *Note `TIMESTAMP':
datetime. values in these formats:

   * As a string in either `'YYYY-MM-DD HH:MM:SS'' or `'YY-MM-DD
     HH:MM:SS'' format. A `relaxed' syntax is permitted here, too: Any
     punctuation character may be used as the delimiter between date
     parts or time parts. For example, `'2012-12-31 11:30:45'',
     `'2012^12^31 11+30+45'', `'2012/12/31 11*30*45'', and `'2012@12@31
     11^30^45'' are equivalent.

   * As a string with no delimiters in either `'YYYYMMDDHHMMSS'' or
     `'YYMMDDHHMMSS'' format, provided that the string makes sense as a
     date. For example, `'20070523091528'' and `'070523091528'' are
     interpreted as `'2007-05-23 09:15:28'', but `'071122129015'' is
     illegal (it has a nonsensical minute part) and becomes `'0000-00-00
     00:00:00''.

   * As a number in either `YYYYMMDDHHMMSS' or `YYMMDDHHMMSS' format,
     provided that the number makes sense as a date. For example,
     `19830905132800' and `830905132800' are interpreted as
     `'1983-09-05 13:28:00''.

A *Note `DATETIME': datetime. or *Note `TIMESTAMP': datetime. value can
include a trailing fractional seconds part in up to microseconds (6
digits) precision. Although this fractional part is recognized, it is
discarded from values stored into *Note `DATETIME': datetime. or *Note
`TIMESTAMP': datetime. columns. For information about fractional
seconds support in MySQL, see *Note fractional-seconds::.

Dates containing two-digit year values are ambiguous because the
century is unknown. MySQL interprets two-digit year values using these
rules:

   * Year values in the range `70-99' are converted to `1970-1999'.

   * Year values in the range `00-69' are converted to `2000-2069'.

See also *Note two-digit-years::.

For values specified as strings that include date part delimiters, it
is unnecessary to specify two digits for month or day values that are
less than `10'.  `'2015-6-9'' is the same as `'2015-06-09''. Similarly,
for values specified as strings that include time part delimiters, it
is unnecessary to specify two digits for hour, minute, or second values
that are less than `10'. `'2015-10-30 1:2:3'' is the same as
`'2015-10-30 01:02:03''.

Values specified as numbers should be 6, 8, 12, or 14 digits long. If a
number is 8 or 14 digits long, it is assumed to be in `YYYYMMDD' or
`YYYYMMDDHHMMSS' format and that the year is given by the first 4
digits. If the number is 6 or 12 digits long, it is assumed to be in
`YYMMDD' or `YYMMDDHHMMSS' format and that the year is given by the
first 2 digits. Numbers that are not one of these lengths are
interpreted as though padded with leading zeros to the closest length.

Values specified as nondelimited strings are interpreted according
their length. For a string 8 or 14 characters long, the year is assumed
to be given by the first 4 characters.  Otherwise, the year is assumed
to be given by the first 2 characters. The string is interpreted from
left to right to find year, month, day, hour, minute, and second
values, for as many parts as are present in the string. This means you
should not use strings that have fewer than 6 characters. For example,
if you specify `'9903'', thinking that represents March, 1999, MySQL
converts it to the `zero' date value. This occurs because the year and
month values are `99' and `03', but the day part is completely missing.
However, you can explicitly specify a value of zero to represent
missing month or day parts. For example, to insert the value
`'1999-03-00'', use `'990300''.

MySQL recognizes *Note `TIME': time. values in these formats:

   * As a string in `'D HH:MM:SS'' format. You can also use one of the
     following `relaxed' syntaxes: `'HH:MM:SS'', `'HH:MM'', `'D HH:MM'',
     `'D HH'', or `'SS''. Here `D' represents days and can have a value
     from 0 to 34.

   * As a string with no delimiters in `'HHMMSS'' format, provided that
     it makes sense as a time. For example, `'101112'' is understood as
     `'10:11:12'', but `'109712'' is illegal (it has a nonsensical
     minute part) and becomes `'00:00:00''.

   * As a number in `HHMMSS' format, provided that it makes sense as a
     time. For example, `101112' is understood as `'10:11:12''. The
     following alternative formats are also understood: `SS', `MMSS',
     or `HHMMSS'.

A trailing fractional seconds part is recognized in the `'D
HH:MM:SS.fraction'', `'HH:MM:SS.fraction'', `'HHMMSS.fraction'', and
`HHMMSS.fraction' time formats, where `fraction' is the fractional part
in up to microseconds (6 digits) precision. Although this fractional
part is recognized, it is discarded from values stored into *Note
`TIME': time. columns. For information about fractional seconds support
in MySQL, see *Note fractional-seconds::.

For *Note `TIME': time. values specified as strings that include a time
part delimiter, it is unnecessary to specify two digits for hours,
minutes, or seconds values that are less than `10'. `'8:3:2'' is the
same as `'08:03:02''.


File: manual.info,  Node: hexadecimal-literals,  Next: boolean-literals,  Prev: date-and-time-literals,  Up: literals

9.1.4 Hexadecimal Literals
--------------------------

MySQL supports hexadecimal values, written using `X'VAL'', `x'VAL'', or
`0xVAL' format, where VAL contains hexadecimal digits (`0..9', `A..F').
Lettercase of the digits does not matter. For values written using
`X'VAL'' or `x'VAL'' format, VAL must contain an even number of digits.
For values written using `0xVAL syntax', values that contain an odd
number of digits are treated as having an extra leading `0'. For
example, `0x0a' and `0xaaa' are interpreted as `0x0a' and `0x0aaa'.

In numeric contexts, hexadecimal values act like integers (64-bit
precision). In string contexts, they act like binary strings, where
each pair of hex digits is converted to a character:

     mysql> SELECT X'4D7953514C';
             -> 'MySQL'
     mysql> SELECT 0x0a+0;
             -> 10
     mysql> SELECT 0x5061756c;
             -> 'Paul'

The default type of a hexadecimal value is a string. If you want to
ensure that the value is treated as a number, you can use `CAST(... AS
UNSIGNED)':

     mysql> SELECT 0x41, CAST(0x41 AS UNSIGNED);
             -> 'A', 65

The `X'HEXSTRING'' syntax is based on standard SQL. The `0x' syntax is
based on ODBC. Hexadecimal strings are often used by ODBC to supply
values for *Note `BLOB': blob.  columns.

You can convert a string or a number to a string in hexadecimal format
with the `HEX()' function:

     mysql> SELECT HEX('cat');
             -> '636174'
     mysql> SELECT 0x636174;
             -> 'cat'


File: manual.info,  Node: boolean-literals,  Next: bit-field-literals,  Prev: hexadecimal-literals,  Up: literals

9.1.5 Boolean Literals
----------------------

The constants `TRUE' and `FALSE' evaluate to `1' and `0', respectively.
The constant names can be written in any lettercase.

     mysql> SELECT TRUE, true, FALSE, false;
             -> 1, 1, 0, 0


File: manual.info,  Node: bit-field-literals,  Next: null-values,  Prev: boolean-literals,  Up: literals

9.1.6 Bit-Field Literals
------------------------

Beginning with MySQL 5.0.3, bit-field values can be written using
`b'VALUE'' or `0bVALUE' notation.  VALUE is a binary value written using
zeros and ones.

Bit-field notation is convenient for specifying values to be assigned
to *Note `BIT': numeric-types. columns:


     mysql> CREATE TABLE t (b BIT(8));
     mysql> INSERT INTO t SET b = b'11111111';
     mysql> INSERT INTO t SET b = b'1010';
     mysql> INSERT INTO t SET b = b'0101';

Bit values are returned as binary values. To display them in printable
form, add 0 or use a conversion function such as `BIN()'. High-order 0
bits are not displayed in the converted value.

     mysql> SELECT b+0, BIN(b+0), OCT(b+0), HEX(b+0) FROM t;
     +------+----------+----------+----------+
     | b+0  | BIN(b+0) | OCT(b+0) | HEX(b+0) |
     +------+----------+----------+----------+
     |  255 | 11111111 | 377      | FF       |
     |   10 | 1010     | 12       | A        |
     |    5 | 101      | 5        | 5        |
     +------+----------+----------+----------+

Bit values assigned to user variables are treated as binary strings. To
assign a bit value as a number to a user variable, use `CAST()' or `+0':

     mysql> SET @v1 = 0b1000001;
     mysql> SET @v2 = CAST(0b1000001 AS UNSIGNED), @v3 = 0b1000001+0;
     mysql> SELECT @v1, @v2, @v3;
     +------+------+------+
     | @v1  | @v2  | @v3  |
     +------+------+------+
     | A    |   65 |   65 |
     +------+------+------+


File: manual.info,  Node: null-values,  Prev: bit-field-literals,  Up: literals

9.1.7 `NULL' Values
-------------------

The `NULL' value means `no data.' `NULL' can be written in any
lettercase. A synonym is `\N' (case sensitive).

For text file import or export operations performed with *Note `LOAD
DATA INFILE': load-data. or *Note `SELECT ... INTO OUTFILE':
select-into, `NULL' is represented by the `\N' sequence. See *Note
load-data::.

Be aware that the `NULL' value is different from values such as `0' for
numeric types or the empty string for string types. For more
information, see *Note problems-with-null::.


File: manual.info,  Node: identifiers,  Next: reserved-words,  Prev: literals,  Up: language-structure

9.2 Schema Object Names
=======================

* Menu:

* identifier-qualifiers::        Identifier Qualifiers
* identifier-case-sensitivity::  Identifier Case Sensitivity
* function-resolution::          Function Name Parsing and Resolution

Certain objects within MySQL, including database, table, index, column,
alias, view, stored procedure, partition, and other object names are
known as identifiers. This section describes the permissible syntax for
identifiers in MySQL.  *Note identifier-case-sensitivity::, describes
which types of identifiers are case sensitive and under what conditions.

An identifier may be quoted or unquoted. If an identifier contains
special characters or is a reserved word, you _must_ quote it whenever
you refer to it.  (Exception: A reserved word that follows a period in
a qualified name must be an identifier, so it need not be quoted.)
Reserved words are listed at *Note reserved-words::.

Identifiers are converted to Unicode internally. They may contain these
characters:

   * Permitted characters in unquoted identifiers:

        * ASCII: [0-9,a-z,A-Z$_] (basic Latin letters, digits 0-9,
          dollar, underscore)

        * Extended: U+0080 .. U+FFFF

   * Permitted characters in quoted identifiers include the full
     Unicode Basic Multilingual Plane (BMP), except U+0000:

        * ASCII: U+0001 .. U+007F

        * Extended: U+0080 .. U+FFFF

   * ASCII NUL (U+0000) and supplementary characters (U+10000 and
     higher) are not permitted in quoted or unquoted identifiers.

   * Identifiers may begin with a digit but unless quoted may not
     consist solely of digits.

   * Database, table, and column names cannot end with space characters.

   * Database and table names cannot contain ``/'', ``\'', ``.'', or
     characters that are not permitted in file names.

The identifier quote character is the backtick (```''):

     mysql> SELECT * FROM `select` WHERE `select`.id > 100;

If the `ANSI_QUOTES' SQL mode is enabled, it is also permissible to
quote identifiers within double quotation marks:

     mysql> CREATE TABLE "test" (col INT);
     ERROR 1064: You have an error in your SQL syntax...
     mysql> SET sql_mode='ANSI_QUOTES';
     mysql> CREATE TABLE "test" (col INT);
     Query OK, 0 rows affected (0.00 sec)

The `ANSI_QUOTES' mode causes the server to interpret double-quoted
strings as identifiers.  Consequently, when this mode is enabled,
string literals must be enclosed within single quotation marks. They
cannot be enclosed within double quotation marks. The server SQL mode
is controlled as described in *Note server-sql-mode::.

Identifier quote characters can be included within an identifier if you
quote the identifier. If the character to be included within the
identifier is the same as that used to quote the identifier itself,
then you need to double the character. The following statement creates
a table named `a`b' that contains a column named `c"d':

     mysql> CREATE TABLE `a``b` (`c"d` INT);

In the select list of a query, a quoted column alias can be specified
using identifier or string quoting characters:

     mysql> SELECT 1 AS `one`, 2 AS 'two';
     +-----+-----+
     | one | two |
     +-----+-----+
     |   1 |   2 |
     +-----+-----+

Elsewhere in the statement, quoted references to the alias must use
identifier quoting or the reference is treated as a string literal.

It is recommended that you do not use names that begin with `Me' or
`MeN', where M and N are integers. For example, avoid using `1e' as an
identifier, because an expression such as `1e+3' is ambiguous. Depending
on context, it might be interpreted as the expression `1e + 3' or as
the number `1e+3'.

Be careful when using `MD5()' to produce table names because it can
produce names in illegal or ambiguous formats such as those just
described.

A user variable cannot be used directly in an SQL statement as an
identifier or as part of an identifier. See *Note user-variables::, for
more information and examples of workarounds.

The following table describes the maximum length for each type of
identifier.

Identifier  Maximum
            Length
            (characters)
Database    64
Table       64
Column      64
Index       64
Constraint  64
Stored      64
Procedure   
or Function 
Trigger     64
View        64
Alias       256 (see
            exception
            following
            table)
Compound    16
Statement   
Label       

As of MySQL 5.0.52, aliases for column names in *Note `CREATE VIEW':
create-view. statements are checked against the maximum column length
of 64 characters (not the maximum alias length of 256 characters).

Identifiers are stored using Unicode (UTF-8). This applies to
identifiers in table definitions that are stored in `.frm' files and to
identifiers stored in the grant tables in the `mysql' database. The
sizes of the identifier string columns in the grant tables are measured
in characters. You can use multi-byte characters without reducing the
number of characters permitted for values stored in these columns,
something not true prior to MySQL 4.1. As indicated earlier, the
permissible Unicode characters are those in the Basic Multilingual
Plane (BMP). Supplementary characters are not permitted.


File: manual.info,  Node: identifier-qualifiers,  Next: identifier-case-sensitivity,  Prev: identifiers,  Up: identifiers

9.2.1 Identifier Qualifiers
---------------------------

MySQL permits names that consist of a single identifier or multiple
identifiers. The components of a multiple-part name must be separated
by period (``.'') characters. The initial parts of a multiple-part name
act as qualifiers that affect the context within which the final
identifier is interpreted.

In MySQL, you can refer to a table column using any of the following
forms.

Column Reference       Meaning
COL_NAME               The column COL_NAME from whichever table used in
                       the statement contains a column of that name.
TBL_NAME.COL_NAME      The column COL_NAME from table TBL_NAME of the
                       default database.
DB_NAME.TBL_NAME.COL_NAMEThe column COL_NAME from table TBL_NAME of the
                       database DB_NAME.

If any components of a multiple-part name require quoting, quote them
individually rather than quoting the name as a whole. For example,
write ``my-table`.`my-column`', not ``my-table.my-column`'.

A reserved word that follows a period in a qualified name must be an
identifier, so in that context it need not be quoted.

You need not specify a TBL_NAME or DB_NAME.TBL_NAME prefix for a column
reference in a statement unless the reference would be ambiguous.
Suppose that tables `t1' and `t2' each contain a column `c', and you
retrieve `c' in a *Note `SELECT': select. statement that uses both `t1'
and `t2'. In this case, `c' is ambiguous because it is not unique among
the tables used in the statement. You must qualify it with a table name
as `t1.c' or `t2.c' to indicate which table you mean. Similarly, to
retrieve from a table `t' in database `db1' and from a table `t' in
database `db2' in the same statement, you must refer to columns in
those tables as `db1.t.COL_NAME' and `db2.t.COL_NAME'.

The syntax `.TBL_NAME' means the table TBL_NAME in the default
database. This syntax is accepted for ODBC compatibility because some
ODBC programs prefix table names with a ``.'' character.


File: manual.info,  Node: identifier-case-sensitivity,  Next: function-resolution,  Prev: identifier-qualifiers,  Up: identifiers

9.2.2 Identifier Case Sensitivity
---------------------------------

In MySQL, databases correspond to directories within the data
directory. Each table within a database corresponds to at least one
file within the database directory (and possibly more, depending on the
storage engine). Consequently, the case sensitivity of the underlying
operating system plays a part in the case sensitivity of database and
table names. This means database and table names are not case sensitive
in Windows, and case sensitive in most varieties of Unix. One notable
exception is Mac OS X, which is Unix-based but uses a default file
system type (HFS+) that is not case sensitive. However, Mac OS X also
supports UFS volumes, which are case sensitive just as on any Unix. See
*Note extensions-to-ansi::. The `lower_case_table_names' system
variable also affects how the server handles identifier case
sensitivity, as described later in this section.

*Note*:

Although database and table names are not case sensitive on some
platforms, you should not refer to a given database or table using
different cases within the same statement. The following statement
would not work because it refers to a table both as `my_table' and as
`MY_TABLE':

     mysql> SELECT * FROM my_table WHERE MY_TABLE.col=1;

Column, index, and stored routine names are not case sensitive on any
platform, nor are column aliases. Trigger names are case sensitive,
which differs from standard SQL.

By default, table aliases are case sensitive on Unix, but not so on
Windows or Mac OS X. The following statement would not work on Unix,
because it refers to the alias both as `a' and as `A':

     mysql> SELECT COL_NAME FROM TBL_NAME AS a
         -> WHERE a.COL_NAME = 1 OR A.COL_NAME = 2;

However, this same statement is permitted on Windows. To avoid problems
caused by such differences, it is best to adopt a consistent
convention, such as always creating and referring to databases and
tables using lowercase names. This convention is recommended for
maximum portability and ease of use.

How table and database names are stored on disk and used in MySQL is
affected by the `lower_case_table_names' system variable, which you can
set when starting *Note `mysqld': mysqld.  `lower_case_table_names' can
take the values shown in the following table. On Unix, the default
value of `lower_case_table_names' is 0. On Windows the default value is
1. On Mac OS X, the default value is 2.

Value   Meaning
`0'     Table and database names are stored on disk using the lettercase
        specified in the *Note `CREATE TABLE': create-table. or *Note
        `CREATE DATABASE': create-database. statement. Name comparisons
        are case sensitive. You should _not_ set this variable to 0 if
        you are running MySQL on a system that has case-insensitive file
        names (such as Windows or Mac OS X). If you force this variable
        to 0 with `--lower-case-table-names=0' on a case-insensitive
        file system and access `MyISAM' tablenames using different
        lettercases, index corruption may result.
`1'     Table names are stored in lowercase on disk and name comparisons
        are not case sensitive. MySQL converts all table names to
        lowercase on storage and lookup. This behavior also applies to
        database names and table aliases.
`2'     Table and database names are stored on disk using the lettercase
        specified in the *Note `CREATE TABLE': create-table. or *Note
        `CREATE DATABASE': create-database. statement, but MySQL
        converts them to lowercase on lookup. Name comparisons are not
        case sensitive. This works _only_ on file systems that are not
        case sensitive!  `InnoDB' table names are stored in lowercase,
        as for `lower_case_table_names=1'.

If you are using MySQL on only one platform, you do not normally have
to change the `lower_case_table_names' variable from its default value.
However, you may encounter difficulties if you want to transfer tables
between platforms that differ in file system case sensitivity. For
example, on Unix, you can have two different tables named `my_table' and
`MY_TABLE', but on Windows these two names are considered identical. To
avoid data transfer problems arising from lettercase of database or
table names, you have two options:

   * Use `lower_case_table_names=1' on all systems. The main
     disadvantage with this is that when you use *Note `SHOW TABLES':
     show-tables. or *Note `SHOW DATABASES': show-databases, you do not
     see the names in their original lettercase.

   * Use `lower_case_table_names=0' on Unix and
     `lower_case_table_names=2' on Windows. This preserves the
     lettercase of database and table names. The disadvantage of this
     is that you must ensure that your statements always refer to your
     database and table names with the correct lettercase on Windows.
     If you transfer your statements to Unix, where lettercase is
     significant, they do not work if the lettercase is incorrect.

     *Exception*: If you are using `InnoDB' tables and you are trying
     to avoid these data transfer problems, you should set
     `lower_case_table_names' to 1 on all platforms to force names to
     be converted to lowercase.

If you plan to set the `lower_case_table_names' system variable to 1 on
Unix, you must first convert your old database and table names to
lowercase before stopping *Note `mysqld': mysqld. and restarting it
with the new variable setting. To do this for an individual table, use
*Note `RENAME TABLE': rename-table.:

     RENAME TABLE T1 TO t1;

To convert one or more entire databases, dump them before setting
`lower_case_table_names', then drop the databases, and reload them
after setting `lower_case_table_names':

  1. Use *Note `mysqldump': mysqldump. to dump each database:

          mysqldump --databases db1 > db1.sql
          mysqldump --databases db2 > db2.sql
          ...

     Do this for each database that must be recreated.

  2. Use `DROP DATABASE' to drop each database.

  3. Stop the server, set `lower_case_table_names', and restart the
     server.

  4. Reload the dump file for each database. Because
     `lower_case_table_names' is set, each database and table name will
     be converted to lowercase as it is recreated:

          mysql < db1.sql
          mysql < db2.sql
          ...

Object names may be considered duplicates if their uppercase forms are
equal according to a binary collation. That is true for names of
cursors, conditions, procedures, functions, savepoints, stored routine
parameters and stored program local variables. It is not true for names
of names of columns, constraints, databases, statements prepared with
*Note `PREPARE': prepare, tables, triggers, users, and user-defined
variables.


File: manual.info,  Node: function-resolution,  Prev: identifier-case-sensitivity,  Up: identifiers

9.2.3 Function Name Parsing and Resolution
------------------------------------------

MySQL 5.0 supports built-in (native) functions, user-defined functions
(UDFs), and stored functions. This section describes how the server
recognizes whether the name of a built-in function is used as a
function call or as an identifier, and how the server determines which
function to use in cases when functions of different types exist with a
given name.

*Built-In Function Name Parsing*

The parser uses default rules for parsing names of built-in functions.
These rules can be changed by enabling the `IGNORE_SPACE' SQL mode.

When the parser encounters a word that is the name of a built-in
function, it must determine whether the name signifies a function call
or is instead a nonexpression reference to an identifier such as a
table or column name. For example, in the following statements, the
first reference to `count' is a function call, whereas the second
reference is a table name:

     SELECT COUNT(*) FROM mytable;
     CREATE TABLE count (i INT);

The parser should recognize the name of a built-in function as
indicating a function call only when parsing what is expected to be an
expression. That is, in nonexpression context, function names are
permitted as identifiers.

However, some built-in functions have special parsing or implementation
considerations, so the parser uses the following rules by default to
distinguish whether their names are being used as function calls or as
identifiers in nonexpression context:

   * To use the name as a function call in an expression, there must be
     no whitespace between the name and the following ``('' parenthesis
     character.

   * Conversely, to use the function name as an identifier, it must not
     be followed immediately by a parenthesis.

The requirement that function calls be written with no whitespace
between the name and the parenthesis applies only to the built-in
functions that have special considerations.  `COUNT' is one such name.
The exact list of function names for which following whitespace
determines their interpretation are those listed in the
`sql_functions[]' array of the `sql/lex.h' source file. Before MySQL
5.1, they are rather numerous (about 200), so you may find it easiest
to treat the no-whitespace requirement as applying to all function
calls. In MySQL 5.1, parser improvements reduce to about 30 the number
of affected function names.

For functions not listed in the `sql_functions[]') array, whitespace
does not matter. They are interpreted as function calls only when used
in expression context and may be used freely as identifiers otherwise.
`ASCII' is one such name. However, for these nonaffected function
names, interpretation may vary in expression context: `FUNC_NAME ()' is
interpreted as a built-in function if there is one with the given name;
if not, `FUNC_NAME ()' is interpreted as a user-defined function or
stored function if one exists with that name.

The `IGNORE_SPACE' SQL mode can be used to modify how the parser treats
function names that are whitespace-sensitive:

   * With `IGNORE_SPACE' disabled, the parser interprets the name as a
     function call when there is no whitespace between the name and the
     following parenthesis. This occurs even when the function name is
     used in nonexpression context:

          mysql> CREATE TABLE count(i INT);
          ERROR 1064 (42000): You have an error in your SQL syntax ...
          near 'count(i INT)'

     To eliminate the error and cause the name to be treated as an
     identifier, either use whitespace following the name or write it
     as a quoted identifier (or both):

          CREATE TABLE count (i INT);
          CREATE TABLE `count`(i INT);
          CREATE TABLE `count` (i INT);

   * With `IGNORE_SPACE' enabled, the parser loosens the requirement
     that there be no whitespace between the function name and the
     following parenthesis. This provides more flexibility in writing
     function calls. For example, either of the following function
     calls are legal:

          SELECT COUNT(*) FROM mytable;
          SELECT COUNT (*) FROM mytable;

     However, enabling `IGNORE_SPACE' also has the side effect that the
     parser treats the affected function names as reserved words (see
     *Note reserved-words::). This means that a space following the
     name no longer signifies its use as an identifier. The name can be
     used in function calls with or without following whitespace, but
     causes a syntax error in nonexpression context unless it is
     quoted. For example, with `IGNORE_SPACE' enabled, both of the
     following statements fail with a syntax error because the parser
     interprets `count' as a reserved word:

          CREATE TABLE count(i INT);
          CREATE TABLE count (i INT);

     To use the function name in nonexpression context, write it as a
     quoted identifier:

          CREATE TABLE `count`(i INT);
          CREATE TABLE `count` (i INT);

To enable the `IGNORE_SPACE' SQL mode, use this statement:

     SET sql_mode = 'IGNORE_SPACE';

`IGNORE_SPACE' is also enabled by certain other composite modes such as
`ANSI' that include it in their value:

     SET sql_mode = 'ANSI';

Check *Note server-sql-mode::, to see which composite modes enable
`IGNORE_SPACE'.

To minimize the dependency of SQL code on the `IGNORE_SPACE' setting,
use these guidelines:

   * Avoid creating UDFs or stored functions that have the same name as
     a built-in function.

   * Avoid using function names in nonexpression context. For example,
     these statements use `count' (one of the affected function names
     affected by `IGNORE_SPACE'), so they fail with or without
     whitespace following the name if `IGNORE_SPACE' is enabled:

          CREATE TABLE count(i INT);
          CREATE TABLE count (i INT);

     If you must use a function name in nonexpression context, write it
     as a quoted identifier:

          CREATE TABLE `count`(i INT);
          CREATE TABLE `count` (i INT);

*Function Name Resolution*

The following rules describe how the server resolves references to
function names for function creation and invocation:

   * Built-in functions and user-defined functions

     A UDF can be created with the same name as a built-in function but
     the UDF cannot be invoked because the parser resolves invocations
     of the function to refer to the built-in function. For example, if
     you create a UDF named `ABS', references to `ABS()' invoke the
     built-in function.

   * Built-in functions and stored functions

     It is possible to create a stored function with the same name as a
     built-in function, but to invoke the stored function it is
     necessary to qualify it with a database name.  For example, if you
     create a stored function named `PI' in the `test' database, you
     invoke it as `test.PI()' because the server resolves `PI()' as a
     reference to the built-in function.

   * User-defined functions and stored functions

     User-defined functions and stored functions share the same
     namespace, so you cannot create a UDF and a stored function with
     the same name.

The preceding function name resolution rules have implications for
upgrading to versions of MySQL that implement new built-in functions:

   * If you have already created a user-defined function with a given
     name and upgrade MySQL to a version that implements a new built-in
     function with the same name, the UDF becomes inaccessible. To
     correct this, use *Note `DROP FUNCTION': drop-function. to drop
     the UDF, and then use *Note `CREATE FUNCTION': create-function. to
     re-create the UDF with a different nonconflicting name.

   * If a new version of MySQL implements a built-in function with the
     same name as an existing stored function, you have two choices:
     Rename the stored function to use a nonconflicting name, or change
     calls to the function so that they use a schema qualifier (that
     is, use `SCHEMA_NAME.FUNC_NAME()' syntax).


File: manual.info,  Node: reserved-words,  Next: user-variables,  Prev: identifiers,  Up: language-structure

9.3 Reserved Words
==================

Certain words such as *Note `SELECT': select, *Note `DELETE': delete, or
*Note `BIGINT': numeric-types. are reserved and require special
treatment for use as identifiers such as table and column names. This
may also be true for the names of built-in functions.

Reserved words are permitted as identifiers if you quote them as
described in *Note identifiers:::

     mysql> CREATE TABLE interval (begin INT, end INT);
     ERROR 1064 (42000): You have an error in your SQL syntax ...
     near 'interval (begin INT, end INT)'

     mysql> CREATE TABLE `interval` (begin INT, end INT);
     Query OK, 0 rows affected (0.01 sec)

Exception: A word that follows a period in a qualified name must be an
identifier, so it need not be quoted even if it is reserved:

     mysql> CREATE TABLE mydb.interval (begin INT, end INT);
     Query OK, 0 rows affected (0.01 sec)

Names of built-in functions are permitted as identifiers but may
require care to be used as such. For example, `COUNT' is acceptable as
a column name. However, by default, no whitespace is permitted in
function invocations between the function name and the following ``(''
character. This requirement enables the parser to distinguish whether
the name is used in a function call or in nonfunction context. For
further detail on recognition of function names, see *Note
function-resolution::.

The words in the following table are explicitly reserved in MySQL 5.0.
At some point, you might upgrade to a higher version, so it is a good
idea to have a look at future reserved words, too. You can find these
in the manuals that cover higher versions of MySQL. Most of the words
in the table are forbidden by standard SQL as column or table names
(for example, `GROUP'). A few are reserved because MySQL needs them and
uses a `yacc' parser. A reserved word can be used as an identifier if
you quote it.

For a more detailed list of reserved words, including differences
between versions, see Reserved Words in MySQL 5.0
(http://dev.mysql.com/doc/mysqld-version-reference/en/mysqld-version-reference-reservedwords-5-0.html).

`ADD'                    `ALL'                    `ALTER'
`ANALYZE'                `AND'                    `AS'
`ASC'                    `ASENSITIVE'             `BEFORE'
`BETWEEN'                `BIGINT'                 `BINARY'
`BLOB'                   `BOTH'                   `BY'
`CALL'                   `CASCADE'                `CASE'
`CHANGE'                 `CHAR'                   `CHARACTER'
`CHECK'                  `COLLATE'                `COLUMN'
`CONDITION'              `CONSTRAINT'             `CONTINUE'
`CONVERT'                `CREATE'                 `CROSS'
`CURRENT_DATE'           `CURRENT_TIME'           `CURRENT_TIMESTAMP'
`CURRENT_USER'           `CURSOR'                 `DATABASE'
`DATABASES'              `DAY_HOUR'               `DAY_MICROSECOND'
`DAY_MINUTE'             `DAY_SECOND'             `DEC'
`DECIMAL'                `DECLARE'                `DEFAULT'
`DELAYED'                `DELETE'                 `DESC'
`DESCRIBE'               `DETERMINISTIC'          `DISTINCT'
`DISTINCTROW'            `DIV'                    `DOUBLE'
`DROP'                   `DUAL'                   `EACH'
`ELSE'                   `ELSEIF'                 `ENCLOSED'
`ESCAPED'                `EXISTS'                 `EXIT'
`EXPLAIN'                `FALSE'                  `FETCH'
`FLOAT'                  `FLOAT4'                 `FLOAT8'
`FOR'                    `FORCE'                  `FOREIGN'
`FROM'                   `FULLTEXT'               `GRANT'
`GROUP'                  `HAVING'                 `HIGH_PRIORITY'
`HOUR_MICROSECOND'       `HOUR_MINUTE'            `HOUR_SECOND'
`IF'                     `IGNORE'                 `IN'
`INDEX'                  `INFILE'                 `INNER'
`INOUT'                  `INSENSITIVE'            `INSERT'
`INT'                    `INT1'                   `INT2'
`INT3'                   `INT4'                   `INT8'
`INTEGER'                `INTERVAL'               `INTO'
`IS'                     `ITERATE'                `JOIN'
`KEY'                    `KEYS'                   `KILL'
`LEADING'                `LEAVE'                  `LEFT'
`LIKE'                   `LIMIT'                  `LINES'
`LOAD'                   `LOCALTIME'              `LOCALTIMESTAMP'
`LOCK'                   `LONG'                   `LONGBLOB'
`LONGTEXT'               `LOOP'                   `LOW_PRIORITY'
`MATCH'                  `MEDIUMBLOB'             `MEDIUMINT'
`MEDIUMTEXT'             `MIDDLEINT'              `MINUTE_MICROSECOND'
`MINUTE_SECOND'          `MOD'                    `MODIFIES'
`NATURAL'                `NOT'                    `NO_WRITE_TO_BINLOG'
`NULL'                   `NUMERIC'                `ON'
`OPTIMIZE'               `OPTION'                 `OPTIONALLY'
`OR'                     `ORDER'                  `OUT'
`OUTER'                  `OUTFILE'                `PRECISION'
`PRIMARY'                `PROCEDURE'              `PURGE'
`READ'                   `READS'                  `REAL'
`REFERENCES'             `REGEXP'                 `RELEASE'
`RENAME'                 `REPEAT'                 `REPLACE'
`REQUIRE'                `RESTRICT'               `RETURN'
`REVOKE'                 `RIGHT'                  `RLIKE'
`SCHEMA'                 `SCHEMAS'                `SECOND_MICROSECOND'
`SELECT'                 `SENSITIVE'              `SEPARATOR'
`SET'                    `SHOW'                   `SMALLINT'
`SONAME'                 `SPATIAL'                `SPECIFIC'
`SQL'                    `SQLEXCEPTION'           `SQLSTATE'
`SQLWARNING'             `SQL_BIG_RESULT'         `SQL_CALC_FOUND_ROWS'
`SQL_SMALL_RESULT'       `SSL'                    `STARTING'
`STRAIGHT_JOIN'          `TABLE'                  `TERMINATED'
`THEN'                   `TINYBLOB'               `TINYINT'
`TINYTEXT'               `TO'                     `TRAILING'
`TRIGGER'                `TRUE'                   `UNDO'
`UNION'                  `UNIQUE'                 `UNLOCK'
`UNSIGNED'               `UPDATE'                 `USAGE'
`USE'                    `USING'                  `UTC_DATE'
`UTC_TIME'               `UTC_TIMESTAMP'          `VALUES'
`VARBINARY'              `VARCHAR'                `VARCHARACTER'
`VARYING'                `WHEN'                   `WHERE'
`WHILE'                  `WITH'                   `WRITE'
`XOR'                    `YEAR_MONTH'             `ZEROFILL'

The following are new reserved words in MySQL 5.0:

`ASENSITIVE'             `CALL'                   `CONDITION'
`CONNECTION'             `CONTINUE'               `CURSOR'
`DECLARE'                `DETERMINISTIC'          `EACH'
`ELSEIF'                 `EXIT'                   `FETCH'
`GOTO'                   `INOUT'                  `INSENSITIVE'
`ITERATE'                `LABEL'                  `LEAVE'
`LOOP'                   `MODIFIES'               `OUT'
`READS'                  `RELEASE'                `REPEAT'
`RETURN'                 `SCHEMA'                 `SCHEMAS'
`SENSITIVE'              `SPECIFIC'               `SQL'
`SQLEXCEPTION'           `SQLSTATE'               `SQLWARNING'
`TRIGGER'                `UNDO'                   `UPGRADE'
`WHILE'                                           

MySQL permits some keywords to be used as unquoted identifiers because
many people previously used them. Examples are those in the following
list:

   * `ACTION'

   * *Note `BIT': numeric-types.

   * *Note `DATE': datetime.

   * *Note `ENUM': enum.

   * `NO'

   * *Note `TEXT': blob.

   * *Note `TIME': time.

   * *Note `TIMESTAMP': datetime.


File: manual.info,  Node: user-variables,  Next: expressions,  Prev: reserved-words,  Up: language-structure

9.4 User-Defined Variables
==========================

You can store a value in a user-defined variable in one statement and
then refer to it later in another statement. This enables you to pass
values from one statement to another.  _User-defined variables are
connection-specific_. That is, a user variable defined by one client
cannot be seen or used by other clients. All variables for a given
client connection are automatically freed when that client exits.

User variables are written as `@VAR_NAME', where the variable name
VAR_NAME consists of alphanumeric characters, ``.'', ``_'', and ``$''.
A user variable name can contain other characters if you quote it as a
string or identifier (for example, `@'my-var'', `@"my-var"', or
`@`my-var`').

User variable names are not case sensitive in MySQL 5.0 and up, but are
case sensitive before MySQL 5.0.

One way to set a user-defined variable is by issuing a *Note `SET':
set-option.  statement:

     SET @VAR_NAME = EXPR [, @VAR_NAME = EXPR] ...

For *Note `SET': set-option, either `=' or `:=' can be used as the
assignment operator.

You can also assign a value to a user variable in statements other than
*Note `SET': set-option. In this case, the assignment operator must be
`:=' and not `=' because the latter is treated as the comparison
operator `=' in non-*Note `SET': set-option.  statements:

     mysql> SET @t1=1, @t2=2, @t3:=4;
     mysql> SELECT @t1, @t2, @t3, @t4 := @t1+@t2+@t3;
     +------+------+------+--------------------+
     | @t1  | @t2  | @t3  | @t4 := @t1+@t2+@t3 |
     +------+------+------+--------------------+
     |    1 |    2 |    4 |                  7 |
     +------+------+------+--------------------+

User variables can be assigned a value from a limited set of data
types: integer, decimal, floating-point, binary or nonbinary string, or
`NULL' value. Assignment of decimal and real values does not preserve
the precision or scale of the value. A value of a type other than one
of the permissible types is converted to a permissible type. For
example, a value having a temporal or spatial data type is converted to
a binary string.

If a user variable is assigned a nonbinary (character) string value, it
has the same character set and collation as the string.  The
coercibility of user variables is implicit as of MySQL 5.0.3.  (This is
the same coercibility as for table column values.)

Bit values assigned to user variables are treated as binary strings. To
assign a bit value as a number to a user variable, use `CAST()' or `+0':

     mysql> SET @v1 = b'1000001';
     mysql> SET @v2 = CAST(b'1000001' AS UNSIGNED), @v3 = b'1000001'+0;
     mysql> SELECT @v1, @v2, @v3;
     +------+------+------+
     | @v1  | @v2  | @v3  |
     +------+------+------+
     | A    |   65 |   65 |
     +------+------+------+

If the value of a user variable is selected in a result set, it is
returned to the client as a string.

If you refer to a variable that has not been initialized, it has a
value of `NULL' and a type of string.

User variables may be used in most contexts where expressions are
permitted. This does not currently include contexts that explicitly
require a literal value, such as in the `LIMIT' clause of a *Note
`SELECT': select. statement, or the `IGNORE N LINES' clause of a *Note
`LOAD DATA': load-data. statement.

As a general rule, you should never assign a value to a user variable
and read the value within the same statement. You might get the results
you expect, but this is not guaranteed. The order of evaluation for
expressions involving user variables is undefined and may change based
on the elements contained within a given statement; in addition, this
order is not guaranteed to be the same between releases of the MySQL
Server. In `SELECT @a, @a:=@a+1, ...', you might think that MySQL will
evaluate `@a' first and then do an assignment second. However, changing
the statement (for example, by adding a `GROUP BY', `HAVING', or `ORDER
BY' clause) may cause MySQL to select an execution plan with a
different order of evaluation.

Another issue with assigning a value to a variable and reading the
value within the same statement is that the default result type of a
variable is based on its type at the start of the statement. The
following example illustrates this:

     mysql> SET @a='test';
     mysql> SELECT @a,(@a:=20) FROM TBL_NAME;

For this *Note `SELECT': select. statement, MySQL reports to the client
that column one is a string and converts all accesses of `@a' to
strings, even though @a is set to a number for the second row. After the
*Note `SELECT': select. statement executes, `@a' is regarded as a
number for the next statement.

To avoid problems with this behavior, either do not assign a value to
and read the value of the same variable within a single statement, or
else set the variable to `0', `0.0', or `''' to define its type before
you use it.

In a *Note `SELECT': select. statement, each select expression is
evaluated only when sent to the client. This means that in a `HAVING',
`GROUP BY', or `ORDER BY' clause, referring to a variable that is
assigned a value in the select expression list does _not_ work as
expected:

     mysql> SELECT (@aa:=id) AS a, (@aa+3) AS b FROM TBL_NAME HAVING b=5;

The reference to `b' in the `HAVING' clause refers to an alias for an
expression in the select list that uses `@aa'.  This does not work as
expected: `@aa' contains the value of `id' from the previous selected
row, not from the current row.

User variables are intended to provide data values. They cannot be used
directly in an SQL statement as an identifier or as part of an
identifier, such as in contexts where a table or database name is
expected, or as a reserved word such as *Note `SELECT': select. This is
true even if the variable is quoted, as shown in the following example:

     mysql> SELECT c1 FROM t;
     +----+
     | c1 |
     +----+
     |  0 |
     +----+
     |  1 |
     +----+
     2 rows in set (0.00 sec)

     mysql> SET @col = "c1";
     Query OK, 0 rows affected (0.00 sec)

     mysql> SELECT @col FROM t;
     +------+
     | @col |
     +------+
     | c1   |
     +------+
     1 row in set (0.00 sec)

     mysql> SELECT `@col` FROM t;
     `ERROR 1054 (42S22): Unknown column '@col' in 'field list''

     mysql> SET @col = "`c1`";
     Query OK, 0 rows affected (0.00 sec)

     mysql> SELECT @col FROM t;
     +------+
     | @col |
     +------+
     | `c1` |
     +------+
     1 row in set (0.00 sec)

An exception to this principle that user variables cannot be used to
provide identifiers is that if you are constructing a string for use as
a prepared statement to be executed later. In this case, user variables
can be used to provide any part of the statement. The following example
illustrates how this can be done:

     mysql> SET @c = "c1";
     Query OK, 0 rows affected (0.00 sec)

     mysql> SET @s = CONCAT("SELECT ", @c, " FROM t");
     Query OK, 0 rows affected (0.00 sec)

     mysql> PREPARE stmt FROM @s;
     Query OK, 0 rows affected (0.04 sec)
     Statement prepared

     mysql> EXECUTE stmt;
     +----+
     | c1 |
     +----+
     |  0 |
     +----+
     |  1 |
     +----+
     2 rows in set (0.00 sec)

     mysql> DEALLOCATE PREPARE stmt;
     Query OK, 0 rows affected (0.00 sec)

See *Note sql-syntax-prepared-statements::, for more information.

A similar technique can be used in application programs to construct
SQL statements using program variables, as shown here using PHP 5:

     <?php
       $mysqli = new mysqli("localhost", "user", "pass", "test");

       if( mysqli_connect_errno() )
         die("Connection failed: %s\n", mysqli_connect_error());

       $col = "c1";

       $query = "SELECT $col FROM t";

       $result = $mysqli->query($query);

       while($row = $result->fetch_assoc())
       {
         echo "<p>" . $row["$col"] . "</p>\n";
       }

       $result->close();

       $mysqli->close();
     ?>

Assembling an SQL statement in this fashion is sometimes known as
`Dynamic SQL'.


File: manual.info,  Node: expressions,  Next: comments,  Prev: user-variables,  Up: language-structure

9.5 Expression Syntax
=====================

The following rules define expression syntax in MySQL. The grammar
shown here is based on that given in the `sql/sql_yacc.yy' file of
MySQL source distributions. See the notes after the grammar for
additional information about some of the terms. Operator precedence is
given in *Note operator-precedence::.

     EXPR:
         EXPR OR EXPR
       | EXPR || EXPR
       | EXPR XOR EXPR
       | EXPR AND EXPR
       | EXPR && EXPR
       | NOT EXPR
       | ! EXPR
       | BOOLEAN_PRIMARY IS [NOT] {TRUE | FALSE | UNKNOWN}
       | BOOLEAN_PRIMARY

     BOOLEAN_PRIMARY:
         BOOLEAN_PRIMARY IS [NOT] NULL
       | BOOLEAN_PRIMARY <=> PREDICATE
       | BOOLEAN_PRIMARY COMPARISON_OPERATOR PREDICATE
       | BOOLEAN_PRIMARY COMPARISON_OPERATOR {ALL | ANY} (SUBQUERY)
       | PREDICATE

     COMPARISON_OPERATOR: = | >= | > | <= | < | <> | !=

     PREDICATE:
         BIT_EXPR [NOT] IN (SUBQUERY)
       | BIT_EXPR [NOT] IN (EXPR [, EXPR] ...)
       | BIT_EXPR [NOT] BETWEEN BIT_EXPR AND PREDICATE
       | BIT_EXPR SOUNDS LIKE BIT_EXPR
       | BIT_EXPR [NOT] LIKE SIMPLE_EXPR [ESCAPE SIMPLE_EXPR]
       | BIT_EXPR [NOT] REGEXP BIT_EXPR
       | BIT_EXPR

     BIT_EXPR:
         BIT_EXPR | BIT_EXPR
       | BIT_EXPR & BIT_EXPR
       | BIT_EXPR << BIT_EXPR
       | BIT_EXPR >> BIT_EXPR
       | BIT_EXPR + BIT_EXPR
       | BIT_EXPR - BIT_EXPR
       | BIT_EXPR * BIT_EXPR
       | BIT_EXPR / BIT_EXPR
       | BIT_EXPR DIV BIT_EXPR
       | BIT_EXPR MOD BIT_EXPR
       | BIT_EXPR % BIT_EXPR
       | BIT_EXPR ^ BIT_EXPR
       | BIT_EXPR + INTERVAL_EXPR
       | BIT_EXPR - INTERVAL_EXPR
       | SIMPLE_EXPR

     SIMPLE_EXPR:
         LITERAL
       | IDENTIFIER
       | FUNCTION_CALL
       | SIMPLE_EXPR COLLATE COLLATION_NAME
       | PARAM_MARKER
       | VARIABLE
       | SIMPLE_EXPR || SIMPLE_EXPR
       | + SIMPLE_EXPR
       | - SIMPLE_EXPR
       | ~ SIMPLE_EXPR
       | ! SIMPLE_EXPR
       | BINARY SIMPLE_EXPR
       | (EXPR [, EXPR] ...)
       | ROW (EXPR, EXPR [, EXPR] ...)
       | (SUBQUERY)
       | EXISTS (SUBQUERY)
       | {IDENTIFIER EXPR}
       | MATCH_EXPR
       | CASE_EXPR
       | INTERVAL_EXPR

Notes:

For literal value syntax, see *Note literals::.

For identifier syntax, see *Note identifiers::.

Variables can be user variables, system variables, or stored program
local variables or parameters:

   * User variables: *Note user-variables::

   * System variables: *Note using-system-variables::

   * Local variables: *Note declare-local-variable::

   * Parameters: *Note create-procedure::

PARAM_MARKER is `'?'' as used in prepared statements for placeholders.
See *Note prepare::.

`(SUBQUERY)' indicates a subquery that returns a single value; that is,
a scalar subquery. See *Note scalar-subqueries::.

`{IDENTIFIER EXPR}' is ODBC escape syntax and is accepted for ODBC
compatibility. The value is EXPR. The curly braces in the syntax should
be written literally; they are not metasyntax as used elsewhere in
syntax descriptions.

MATCH_EXPR indicates a `MATCH' expression. See *Note fulltext-search::.

CASE_EXPR indicates a `CASE' expression. See *Note
control-flow-functions::.

INTERVAL_EXPR represents a time interval. The syntax is `INTERVAL EXPR
UNIT', where UNIT is a specifier such as `HOUR', `DAY', or `WEEK'. For
the full list of UNIT specifiers, see the description of the
`DATE_ADD()' function in *Note date-and-time-functions::.

The meaning of some operators depends on the SQL mode:

   * By default, `||' is a logical `OR' operator. With
     `PIPES_AS_CONCAT' enabled, `||' is string concatenation, with a
     precedence between `^' and the unary operators.

   * By default, `!' has a higher precedence than `NOT' as of MySQL
     5.0.2. For earlier versions, or from 5.0.2 on with
     `HIGH_NOT_PRECEDENCE' enabled, `!' and `NOT' have the same
     precedence.

See *Note server-sql-mode::.


File: manual.info,  Node: comments,  Prev: expressions,  Up: language-structure

9.6 Comment Syntax
==================

MySQL Server supports three comment styles:

   * From a ``#'' character to the end of the line.

   * From a ``-- '' sequence to the end of the line. In MySQL, the ``--
     '' (double-dash) comment style requires the second dash to be
     followed by at least one whitespace or control character (such as
     a space, tab, newline, and so on). This syntax differs slightly
     from standard SQL comment syntax, as discussed in *Note
     ansi-diff-comments::.

   * From a `/*' sequence to the following `*/' sequence, as in the C
     programming language. This syntax enables a comment to extend over
     multiple lines because the beginning and closing sequences need
     not be on the same line.

The following example demonstrates all three comment styles:

     mysql> SELECT 1+1;     # This comment continues to the end of line
     mysql> SELECT 1+1;     -- This comment continues to the end of line
     mysql> SELECT 1 /* this is an in-line comment */ + 1;
     mysql> SELECT 1+
     /*
     this is a
     multiple-line comment
     */
     1;

Nested comments are not supported.

MySQL Server supports some variants of C-style comments. These enable
you to write code that includes MySQL extensions, but is still
portable, by using comments of the following form:

     /*! MYSQL-SPECIFIC CODE */

In this case, MySQL Server parses and executes the code within the
comment as it would any other SQL statement, but other SQL servers will
ignore the extensions. For example, MySQL Server recognizes the
`STRAIGHT_JOIN' keyword in the following statement, but other servers
will not:

     SELECT /*! STRAIGHT_JOIN */ col1 FROM table1,table2 WHERE ...

If you add a version number after the ``!'' character, the syntax within
the comment is executed only if the MySQL version is greater than or
equal to the specified version number. The `TEMPORARY' keyword in the
following comment is executed only by servers from MySQL 3.23.02 or
higher:

     CREATE /*!32302 TEMPORARY */ TABLE t (a INT);

The comment syntax just described applies to how the *Note `mysqld':
mysqld. server parses SQL statements. The *Note `mysql': mysql. client
program also performs some parsing of statements before sending them to
the server. (It does this to determine statement boundaries within a
multiple-statement input line.)

Comments in this format, `/*!12345 ... */', are not stored on the
server. If this format is used to comment stored routines, the comments
will not be retained on the server.

The use of short-form *Note `mysql': mysql. commands such as `\C'
within multi-line `/* ...  */' comments is not supported.


File: manual.info,  Node: globalization,  Next: data-types,  Prev: language-structure,  Up: Top

10 Globalization
****************

* Menu:

* charset::                      Character Set Support
* error-message-language::       Setting the Error Message Language
* adding-character-set::         Adding a Character Set
* adding-collation::             Adding a Collation to a Character Set
* charset-configuration::        Character Set Configuration
* time-zone-support::            MySQL Server Time Zone Support
* locale-support::               MySQL Server Locale Support

This chapter covers issues of globalization, which includes
internationalization (MySQL's capabilities for adapting to local use)
and localization (selecting particular local conventions):

   * MySQL support for character sets in SQL statements.

   * How to configure the server to support different character sets.

   * Selecting the language for error messages.

   * How to set the server's time zone and enable per-connection time
     zone support.

   * Selecting the locale for day and month names.


File: manual.info,  Node: charset,  Next: error-message-language,  Prev: globalization,  Up: globalization

10.1 Character Set Support
==========================

* Menu:

* charset-general::              Character Sets and Collations in General
* charset-mysql::                Character Sets and Collations in MySQL
* charset-syntax::               Specifying Character Sets and Collations
* charset-connection::           Connection Character Sets and Collations
* charset-applications::         Configuring the Character Set and Collation for Applications
* charset-errors::               Character Set for Error Messages
* charset-collations::           Collation Issues
* charset-repertoire::           String Repertoire
* charset-operations::           Operations Affected by Character Set Support
* charset-unicode::              Unicode Support
* charset-metadata::             UTF-8 for Metadata
* charset-conversion::           Column Character Set Conversion
* charset-charsets::             Character Sets and Collations That MySQL Supports

MySQL includes character set support that enables you to store data
using a variety of character sets and perform comparisons according to
a variety of collations. You can specify character sets at the server,
database, table, and column level. MySQL supports the use of character
sets for the `MyISAM', `MEMORY', *Note `NDBCLUSTER': mysql-cluster, and
`InnoDB' storage engines.

This chapter discusses the following topics:

   * What are character sets and collations?

   * The multiple-level default system for character set assignment

   * Syntax for specifying character sets and collations

   * Affected functions and operations

   * Unicode support

   * The character sets and collations that are available, with notes

Character set issues affect not only data storage, but also
communication between client programs and the MySQL server. If you want
the client program to communicate with the server using a character set
different from the default, you'll need to indicate which one. For
example, to use the `utf8' Unicode character set, issue this statement
after connecting to the server:

     SET NAMES 'utf8';

For more information about configuring character sets for application
use and character set-related issues in client/server communication,
see *Note charset-applications::, and *Note charset-connection::.


File: manual.info,  Node: charset-general,  Next: charset-mysql,  Prev: charset,  Up: charset

10.1.1 Character Sets and Collations in General
-----------------------------------------------

A _character set_ is a set of symbols and encodings. A _collation_ is a
set of rules for comparing characters in a character set. Let's make the
distinction clear with an example of an imaginary character set.

Suppose that we have an alphabet with four letters: ``A'', ``B'', ``a'',
``b''. We give each letter a number: ``A'' = 0, ``B'' = 1, ``a'' = 2,
``b'' = 3. The letter ``A'' is a symbol, the number 0 is the *encoding*
for ``A'', and the combination of all four letters and their encodings
is a *character set*.

Suppose that we want to compare two string values, ``A'' and ``B''. The
simplest way to do this is to look at the encodings: 0 for ``A'' and 1
for ``B''. Because 0 is less than 1, we say ``A'' is less than ``B''.
What we've just done is apply a collation to our character set. The
collation is a set of rules (only one rule in this case): `compare the
encodings.' We call this simplest of all possible collations a _binary_
collation.

But what if we want to say that the lowercase and uppercase letters are
equivalent? Then we would have at least two rules: (1) treat the
lowercase letters ``a'' and ``b'' as equivalent to ``A'' and ``B''; (2)
then compare the encodings. We call this a _case-insensitive_
collation. It is a little more complex than a binary collation.

In real life, most character sets have many characters: not just ``A''
and ``B'' but whole alphabets, sometimes multiple alphabets or eastern
writing systems with thousands of characters, along with many special
symbols and punctuation marks. Also in real life, most collations have
many rules, not just for whether to distinguish lettercase, but also
for whether to distinguish accents (an `accent' is a mark attached to a
character as in German ``O"''), and for multiple-character mappings
(such as the rule that ``O"'' = ``OE'' in one of the two German
collations).

MySQL can do these things for you:

   * Store strings using a variety of character sets

   * Compare strings using a variety of collations

   * Mix strings with different character sets or collations in the
     same server, the same database, or even the same table

   * Enable specification of character set and collation at any level

In these respects, MySQL is far ahead of most other database management
systems. However, to use these features effectively, you need to know
what character sets and collations are available, how to change the
defaults, and how they affect the behavior of string operators and
functions.


File: manual.info,  Node: charset-mysql,  Next: charset-syntax,  Prev: charset-general,  Up: charset

10.1.2 Character Sets and Collations in MySQL
---------------------------------------------

The MySQL server can support multiple character sets. To list the
available character sets, use the *Note `SHOW CHARACTER SET':
show-character-set. statement. A partial listing follows.  For more
complete information, see *Note charset-charsets::.

     mysql> SHOW CHARACTER SET;
     +----------+-----------------------------+---------------------+--------+
     | Charset  | Description                 | Default collation   | Maxlen |
     +----------+-----------------------------+---------------------+--------+
     | big5     | Big5 Traditional Chinese    | big5_chinese_ci     |      2 |
     | dec8     | DEC West European           | dec8_swedish_ci     |      1 |
     | cp850    | DOS West European           | cp850_general_ci    |      1 |
     | hp8      | HP West European            | hp8_english_ci      |      1 |
     | koi8r    | KOI8-R Relcom Russian       | koi8r_general_ci    |      1 |
     | latin1   | cp1252 West European        | latin1_swedish_ci   |      1 |
     | latin2   | ISO 8859-2 Central European | latin2_general_ci   |      1 |
     | swe7     | 7bit Swedish                | swe7_swedish_ci     |      1 |
     | ascii    | US ASCII                    | ascii_general_ci    |      1 |
     | ujis     | EUC-JP Japanese             | ujis_japanese_ci    |      3 |
     | sjis     | Shift-JIS Japanese          | sjis_japanese_ci    |      2 |
     | hebrew   | ISO 8859-8 Hebrew           | hebrew_general_ci   |      1 |
     | tis620   | TIS620 Thai                 | tis620_thai_ci      |      1 |
     | euckr    | EUC-KR Korean               | euckr_korean_ci     |      2 |
     | koi8u    | KOI8-U Ukrainian            | koi8u_general_ci    |      1 |
     | gb2312   | GB2312 Simplified Chinese   | gb2312_chinese_ci   |      2 |
     | greek    | ISO 8859-7 Greek            | greek_general_ci    |      1 |
     | cp1250   | Windows Central European    | cp1250_general_ci   |      1 |
     | gbk      | GBK Simplified Chinese      | gbk_chinese_ci      |      2 |
     | latin5   | ISO 8859-9 Turkish          | latin5_turkish_ci   |      1 |
     ...

Any given character set always has at least one collation. It may have
several collations. To list the collations for a character set, use the
*Note `SHOW COLLATION': show-collation. statement. For example, to see
the collations for the `latin1' (cp1252 West European) character set,
use this statement to find those collation names that begin with
`latin1':

     mysql> SHOW COLLATION LIKE 'latin1%';
     +---------------------+---------+----+---------+----------+---------+
     | Collation           | Charset | Id | Default | Compiled | Sortlen |
     +---------------------+---------+----+---------+----------+---------+
     | latin1_german1_ci   | latin1  |  5 |         |          |       0 |
     | latin1_swedish_ci   | latin1  |  8 | Yes     | Yes      |       1 |
     | latin1_danish_ci    | latin1  | 15 |         |          |       0 |
     | latin1_german2_ci   | latin1  | 31 |         | Yes      |       2 |
     | latin1_bin          | latin1  | 47 |         | Yes      |       1 |
     | latin1_general_ci   | latin1  | 48 |         |          |       0 |
     | latin1_general_cs   | latin1  | 49 |         |          |       0 |
     | latin1_spanish_ci   | latin1  | 94 |         |          |       0 |
     +---------------------+---------+----+---------+----------+---------+

The `latin1' collations have the following meanings.

Collation                     Meaning
`latin1_german1_ci'           German DIN-1
`latin1_swedish_ci'           Swedish/Finnish
`latin1_danish_ci'            Danish/Norwegian
`latin1_german2_ci'           German DIN-2
`latin1_bin'                  Binary according to `latin1' encoding
`latin1_general_ci'           Multilingual (Western European)
`latin1_general_cs'           Multilingual (ISO Western European), case
                              sensitive
`latin1_spanish_ci'           Modern Spanish

Collations have these general characteristics:

   * Two different character sets cannot have the same collation.

   * Each character set has one collation that is the _default
     collation_. For example, the default collation for `latin1' is
     `latin1_swedish_ci'. The output for *Note `SHOW CHARACTER SET':
     show-character-set. indicates which collation is the default for
     each displayed character set.

   * There is a convention for collation names: They start with the
     name of the character set with which they are associated, they
     usually include a language name, and they end with `_ci' (case
     insensitive), `_cs' (case sensitive), or `_bin' (binary).

In cases where a character set has multiple collations, it might not be
clear which collation is most suitable for a given application. To
avoid choosing the wrong collation, it can be helpful to perform some
comparisons with representative data values to make sure that a given
collation sorts values the way you expect.

Collation-Charts.Org (http://www.collation-charts.org/) is a useful
site for information that shows how one collation compares to another.


File: manual.info,  Node: charset-syntax,  Next: charset-connection,  Prev: charset-mysql,  Up: charset

10.1.3 Specifying Character Sets and Collations
-----------------------------------------------

* Menu:

* charset-server::               Server Character Set and Collation
* charset-database::             Database Character Set and Collation
* charset-table::                Table Character Set and Collation
* charset-column::               Column Character Set and Collation
* charset-literal::              Character String Literal Character Set and Collation
* charset-national::             National Character Set
* charset-examples::             Examples of Character Set and Collation Assignment
* charset-compatibility::        Compatibility with Other DBMSs

There are default settings for character sets and collations at four
levels: server, database, table, and column. The description in the
following sections may appear complex, but it has been found in
practice that multiple-level defaulting leads to natural and obvious
results.

`CHARACTER SET' is used in clauses that specify a character set.
`CHARSET' can be used as a synonym for `CHARACTER SET'.

Character set issues affect not only data storage, but also
communication between client programs and the MySQL server. If you want
the client program to communicate with the server using a character set
different from the default, you'll need to indicate which one. For
example, to use the `utf8' Unicode character set, issue this statement
after connecting to the server:

     SET NAMES 'utf8';

For more information about character set-related issues in
client/server communication, see *Note charset-connection::.


File: manual.info,  Node: charset-server,  Next: charset-database,  Prev: charset-syntax,  Up: charset-syntax

10.1.3.1 Server Character Set and Collation
...........................................

MySQL Server has a server character set and a server collation. These
can be set at server startup on the command line or in an option file
and changed at runtime.

Initially, the server character set and collation depend on the options
that you use when you start *Note `mysqld': mysqld. You can use
`--character-set-server' for the character set. Along with it, you can
add `--collation-server' for the collation. If you don't specify a
character set, that is the same as saying
`--character-set-server=latin1'.  If you specify only a character set
(for example, `latin1') but not a collation, that is the same as saying
`--character-set-server=latin1' `--collation-server=latin1_swedish_ci'
because `latin1_swedish_ci' is the default collation for `latin1'.
Therefore, the following three commands all have the same effect:

     shell> mysqld
     shell> mysqld --character-set-server=latin1
     shell> mysqld --character-set-server=latin1 \
                --collation-server=latin1_swedish_ci

One way to change the settings is by recompiling. If you want to change
the default server character set and collation when building from
sources, use: `--with-charset' and `--with-collation' as arguments for
`configure'. For example:

     shell> ./configure --with-charset=latin1

Or:

     shell> ./configure --with-charset=latin1 \
                --with-collation=latin1_german1_ci

Both *Note `mysqld': mysqld. and `configure' verify that the character
set/collation combination is valid. If not, each program displays an
error message and terminates.

The server character set and collation are used as default values if
the database character set and collation are not specified in *Note
`CREATE DATABASE': create-database.  statements. They have no other
purpose.

The current server character set and collation can be determined from
the values of the `character_set_server' and `collation_server' system
variables. These variables can be changed at runtime.


File: manual.info,  Node: charset-database,  Next: charset-table,  Prev: charset-server,  Up: charset-syntax

10.1.3.2 Database Character Set and Collation
.............................................

Every database has a database character set and a database collation.
The *Note `CREATE DATABASE': create-database.  and *Note `ALTER
DATABASE': alter-database. statements have optional clauses for
specifying the database character set and collation:

     CREATE DATABASE DB_NAME
         [[DEFAULT] CHARACTER SET CHARSET_NAME]
         [[DEFAULT] COLLATE COLLATION_NAME]

     ALTER DATABASE DB_NAME
         [[DEFAULT] CHARACTER SET CHARSET_NAME]
         [[DEFAULT] COLLATE COLLATION_NAME]

The keyword `SCHEMA' can be used instead of `DATABASE'.

All database options are stored in a text file named `db.opt' that can
be found in the database directory.

The `CHARACTER SET' and `COLLATE' clauses make it possible to create
databases with different character sets and collations on the same
MySQL server.

Example:

     CREATE DATABASE DB_NAME CHARACTER SET latin1 COLLATE latin1_swedish_ci;

MySQL chooses the database character set and database collation in the
following manner:

   * If both `CHARACTER SET X' and `COLLATE Y' are specified, character
     set X and collation Y are used.

   * If `CHARACTER SET X' is specified without `COLLATE', character set
     X and its default collation are used. To see the default collation
     for each character set, use the *Note `SHOW COLLATION':
     show-collation.  statement.

   * If `COLLATE Y' is specified without `CHARACTER SET', the character
     set associated with Y and collation Y are used.

   * Otherwise, the server character set and server collation are used.

The database character set and collation are used as default values for
table definitions if the table character set and collation are not
specified in *Note `CREATE TABLE': create-table. statements. The
database character set also is used by *Note `LOAD DATA INFILE':
load-data. The character set and collation have no other purposes.

The character set and collation for the default database can be
determined from the values of the `character_set_database' and
`collation_database' system variables. The server sets these variables
whenever the default database changes. If there is no default database,
the variables have the same value as the corresponding server-level
system variables, `character_set_server' and `collation_server'.


File: manual.info,  Node: charset-table,  Next: charset-column,  Prev: charset-database,  Up: charset-syntax

10.1.3.3 Table Character Set and Collation
..........................................

Every table has a table character set and a table collation.  The *Note
`CREATE TABLE': create-table. and *Note `ALTER TABLE': alter-table.
statements have optional clauses for specifying the table character set
and collation:

     CREATE TABLE TBL_NAME (COLUMN_LIST)
         [[DEFAULT] CHARACTER SET CHARSET_NAME]
         [COLLATE COLLATION_NAME]]

     ALTER TABLE TBL_NAME
         [[DEFAULT] CHARACTER SET CHARSET_NAME]
         [COLLATE COLLATION_NAME]

Example:

     CREATE TABLE t1 ( ... )
     CHARACTER SET latin1 COLLATE latin1_danish_ci;

MySQL chooses the table character set and collation in the following
manner:

   * If both `CHARACTER SET X' and `COLLATE Y' are specified, character
     set X and collation Y are used.

   * If `CHARACTER SET X' is specified without `COLLATE', character set
     X and its default collation are used. To see the default collation
     for each character set, use the *Note `SHOW COLLATION':
     show-collation.  statement.

   * If `COLLATE Y' is specified without `CHARACTER SET', the character
     set associated with Y and collation Y are used.

   * Otherwise, the database character set and collation are used.

The table character set and collation are used as default values for
column definitions if the column character set and collation are not
specified in individual column definitions.  The table character set
and collation are MySQL extensions; there are no such things in
standard SQL.


File: manual.info,  Node: charset-column,  Next: charset-literal,  Prev: charset-table,  Up: charset-syntax

10.1.3.4 Column Character Set and Collation
...........................................

Every `character' column (that is, a column of type *Note `CHAR': char,
*Note `VARCHAR': char, or *Note `TEXT': blob.) has a column character
set and a column collation. Column definition syntax for *Note `CREATE
TABLE': create-table. and *Note `ALTER TABLE': alter-table. has optional
clauses for specifying the column character set and collation:

     COL_NAME {CHAR | VARCHAR | TEXT} (COL_LENGTH)
         [CHARACTER SET CHARSET_NAME]
         [COLLATE COLLATION_NAME]

These clauses can also be used for *Note `ENUM': enum. and *Note `SET':
set. columns:

     COL_NAME {ENUM | SET} (VAL_LIST)
         [CHARACTER SET CHARSET_NAME]
         [COLLATE COLLATION_NAME]

Examples:

     CREATE TABLE t1
     (
         col1 VARCHAR(5)
           CHARACTER SET latin1
           COLLATE latin1_german1_ci
     );

     ALTER TABLE t1 MODIFY
         col1 VARCHAR(5)
           CHARACTER SET latin1
           COLLATE latin1_swedish_ci;

MySQL chooses the column character set and collation in the following
manner:

   * If both `CHARACTER SET X' and `COLLATE Y' are specified, character
     set X and collation Y are used.

          CREATE TABLE t1
          (
              col1 CHAR(10) CHARACTER SET utf8 COLLATE utf8_unicode_ci
          ) CHARACTER SET latin1 COLLATE latin1_bin;

     The character set and collation are specified for the column, so
     they are used. The column has character set `utf8' and collation
     `utf8_unicode_ci'.

   * If `CHARACTER SET X' is specified without `COLLATE', character set
     X and its default collation are used.

          CREATE TABLE t1
          (
              col1 CHAR(10) CHARACTER SET utf8
          ) CHARACTER SET latin1 COLLATE latin1_bin;

     The character set is specified for the column, but the collation
     is not. The column has character set `utf8' and the default
     collation for `utf8', which is `utf8_general_ci'. To see the
     default collation for each character set, use the *Note `SHOW
     COLLATION': show-collation. statement.

   * If `COLLATE Y' is specified without `CHARACTER SET', the character
     set associated with Y and collation Y are used.

          CREATE TABLE t1
          (
              col1 CHAR(10) COLLATE utf8_polish_ci
          ) CHARACTER SET latin1 COLLATE latin1_bin;

     The collation is specified for the column, but the character set
     is not. The column has collation `utf8_polish_ci' and the
     character set is the one associated with the collation, which is
     `utf8'.

   * Otherwise, the table character set and collation are used.

          CREATE TABLE t1
          (
              col1 CHAR(10)
          ) CHARACTER SET latin1 COLLATE latin1_bin;

     Neither the character set nor collation are specified for the
     column, so the table defaults are used. The column has character
     set `latin1' and collation `latin1_bin'.

The `CHARACTER SET' and `COLLATE' clauses are standard SQL.

If you use *Note `ALTER TABLE': alter-table. to convert a column from
one character set to another, MySQL attempts to map the data values,
but if the character sets are incompatible, there may be data loss.


File: manual.info,  Node: charset-literal,  Next: charset-national,  Prev: charset-column,  Up: charset-syntax

10.1.3.5 Character String Literal Character Set and Collation
.............................................................

Every character string literal has a character set and a collation.

A character string literal may have an optional character set
introducer and `COLLATE' clause:

     [_CHARSET_NAME]'STRING' [COLLATE COLLATION_NAME]

Examples:

     SELECT 'STRING';
     SELECT _latin1'STRING';
     SELECT _latin1'STRING' COLLATE latin1_danish_ci;

For the simple statement `SELECT 'STRING'', the string has the
character set and collation defined by the `character_set_connection'
and `collation_connection' system variables.

The `_CHARSET_NAME' expression is formally called an _introducer_. It
tells the parser, `the string that is about to follow uses character set
X.' Because this has confused people in the past, we emphasize that an
introducer does not change the string to the introducer character set
like `CONVERT()' would do. It does not change the string's value,
although padding may occur. The introducer is just a signal. An
introducer is also legal before standard hex literal and numeric hex
literal notation (`x'LITERAL'' and `0xNNNN'), or before bit-field
literal notation (`b'LITERAL'' and `0bNNNN').

Examples:

     SELECT _latin1 x'AABBCC';
     SELECT _latin1 0xAABBCC;
     SELECT _latin1 b'1100011';
     SELECT _latin1 0b1100011;

MySQL determines a literal's character set and collation in the
following manner:

   * If both _X and `COLLATE Y' are specified, character set X and
     collation Y are used.

   * If _X is specified but `COLLATE' is not specified, character set X
     and its default collation are used. To see the default collation
     for each character set, use the *Note `SHOW COLLATION':
     show-collation.  statement.

   * Otherwise, the character set and collation given by the
     `character_set_connection' and `collation_connection' system
     variables are used.

Examples:

   * A string with `latin1' character set and `latin1_german1_ci'
     collation:

          SELECT _latin1'Mu"ller' COLLATE latin1_german1_ci;

   * A string with `latin1' character set and its default collation
     (that is, `latin1_swedish_ci'):

          SELECT _latin1'Mu"ller';

   * A string with the connection default character set and collation:

          SELECT 'Mu"ller';

Character set introducers and the `COLLATE' clause are implemented
according to standard SQL specifications.

An introducer indicates the character set for the following string, but
does not change now how the parser performs escape processing within
the string. Escapes are always interpreted by the parser according to
the character set given by `character_set_connection'.

The following examples show that escape processing occurs using
`character_set_connection' even in the presence of an introducer. The
examples use `SET NAMES' (which changes `character_set_connection', as
discussed in *Note charset-connection::), and display the resulting
strings using the `HEX()' function so that the exact string contents
can be seen.

Example 1:

     mysql> SET NAMES latin1;
     Query OK, 0 rows affected (0.01 sec)

     mysql> SELECT HEX('a`\n'), HEX(_sjis'a`\n');
     +------------+-----------------+
     | HEX('a`\n') | HEX(_sjis'a`\n') |
     +------------+-----------------+
     | E00A       | E00A            |
     +------------+-----------------+
     1 row in set (0.00 sec)

Here, ``a`'' (hex value `E0') is followed by ``\n'', the escape
sequence for newline. The escape sequence is interpreted using the
`character_set_connection' value of `latin1' to produce a literal
newline (hex value `0A'). This happens even for the second string. That
is, the introducer of `_sjis' does not affect the parser's escape
processing.

Example 2:

     mysql> SET NAMES sjis;
     Query OK, 0 rows affected (0.00 sec)

     mysql> SELECT HEX('a`\n'), HEX(_latin1'a`\n');
     +------------+-------------------+
     | HEX('a`\n') | HEX(_latin1'a`\n') |
     +------------+-------------------+
     | E05C6E     | E05C6E            |
     +------------+-------------------+
     1 row in set (0.04 sec)

Here, `character_set_connection' is `sjis', a character set in which
the sequence of ``a`'' followed by ``\'' (hex values `05' and `5C') is
a valid multi-byte character. Hence, the first two bytes of the string
are interpreted as a single `sjis' character, and the ``\'' is not
interpreted as an escape character. The following ``n'' (hex value
`6E') is not interpreted as part of an escape sequence. This is true
even for the second string; the introducer of `_latin1' does not affect
escape processing.


File: manual.info,  Node: charset-national,  Next: charset-examples,  Prev: charset-literal,  Up: charset-syntax

10.1.3.6 National Character Set
...............................

Standard SQL defines *Note `NCHAR': char. or *Note `NATIONAL CHAR':
char. as a way to indicate that a *Note `CHAR': char. column should use
some predefined character set. MySQL 5.0 uses `utf8' as this predefined
character set. For example, these data type declarations are equivalent:

     CHAR(10) CHARACTER SET utf8
     NATIONAL CHARACTER(10)
     NCHAR(10)

As are these:

     VARCHAR(10) CHARACTER SET utf8
     NATIONAL VARCHAR(10)
     NCHAR VARCHAR(10)
     NATIONAL CHARACTER VARYING(10)
     NATIONAL CHAR VARYING(10)

You can use `N'LITERAL'' (or `n'LITERAL'') to create a string in the
national character set. These statements are equivalent:

     SELECT N'some text';
     SELECT n'some text';
     SELECT _utf8'some text';

For information on upgrading character sets to MySQL 5.0 from versions
prior to 4.1, see the `MySQL 3.23, 4.0, 4.1 Reference Manual'.


File: manual.info,  Node: charset-examples,  Next: charset-compatibility,  Prev: charset-national,  Up: charset-syntax

10.1.3.7 Examples of Character Set and Collation Assignment
...........................................................

The following examples show how MySQL determines default character set
and collation values.

*Example 1: Table and Column Definition*

     CREATE TABLE t1
     (
         c1 CHAR(10) CHARACTER SET latin1 COLLATE latin1_german1_ci
     ) DEFAULT CHARACTER SET latin2 COLLATE latin2_bin;

Here we have a column with a `latin1' character set and a
`latin1_german1_ci' collation. The definition is explicit, so that is
straightforward. Notice that there is no problem with storing a
`latin1' column in a `latin2' table.

*Example 2: Table and Column Definition*

     CREATE TABLE t1
     (
         c1 CHAR(10) CHARACTER SET latin1
     ) DEFAULT CHARACTER SET latin1 COLLATE latin1_danish_ci;

This time we have a column with a `latin1' character set and a default
collation. Although it might seem natural, the default collation is not
taken from the table level. Instead, because the default collation for
`latin1' is always `latin1_swedish_ci', column `c1' has a collation of
`latin1_swedish_ci' (not `latin1_danish_ci').

*Example 3: Table and Column Definition*

     CREATE TABLE t1
     (
         c1 CHAR(10)
     ) DEFAULT CHARACTER SET latin1 COLLATE latin1_danish_ci;

We have a column with a default character set and a default collation.
In this circumstance, MySQL checks the table level to determine the
column character set and collation.  Consequently, the character set
for column `c1' is `latin1' and its collation is `latin1_danish_ci'.

*Example 4: Database, Table, and Column Definition*

     CREATE DATABASE d1
         DEFAULT CHARACTER SET latin2 COLLATE latin2_czech_ci;
     USE d1;
     CREATE TABLE t1
     (
         c1 CHAR(10)
     );

We create a column without specifying its character set and collation.
We're also not specifying a character set and a collation at the table
level. In this circumstance, MySQL checks the database level to
determine the table settings, which thereafter become the column
settings.) Consequently, the character set for column `c1' is `latin2'
and its collation is `latin2_czech_ci'.


File: manual.info,  Node: charset-compatibility,  Prev: charset-examples,  Up: charset-syntax

10.1.3.8 Compatibility with Other DBMSs
.......................................

For MaxDB compatibility these two statements are the same:

     CREATE TABLE t1 (f1 CHAR(N) UNICODE);
     CREATE TABLE t1 (f1 CHAR(N) CHARACTER SET ucs2);


File: manual.info,  Node: charset-connection,  Next: charset-applications,  Prev: charset-syntax,  Up: charset

10.1.4 Connection Character Sets and Collations
-----------------------------------------------

Several character set and collation system variables relate to a
client's interaction with the server. Some of these have been mentioned
in earlier sections:

   * The server character set and collation are the values of the
     `character_set_server' and `collation_server' system variables.

   * The character set and collation of the default database are the
     values of the `character_set_database' and `collation_database'
     system variables.

Additional character set and collation system variables are involved in
handling traffic for the connection between a client and the server.
Every client has connection-related character set and collation system
variables.

A `connection' is what you make when you connect to the server. The
client sends SQL statements, such as queries, over the connection to
the server. The server sends responses, such as result sets or error
messages, over the connection back to the client. This leads to several
questions about character set and collation handling for client
connections, each of which can be answered in terms of system variables:

   * What character set is the statement in when it leaves the client?

     The server takes the `character_set_client' system variable to be
     the character set in which statements are sent by the client.

   * What character set should the server translate a statement to
     after receiving it?

     For this, the server uses the `character_set_connection' and
     `collation_connection' system variables. It converts statements
     sent by the client from `character_set_client' to
     `character_set_connection' (except for string literals that have
     an introducer such as `_latin1' or `_utf8').
     `collation_connection' is important for comparisons of literal
     strings. For comparisons of strings with column values,
     `collation_connection' does not matter because columns have their
     own collation, which has a higher collation precedence.

   * What character set should the server translate to before shipping
     result sets back to the client?

     The `character_set_results' system variable indicates the
     character set in which the server returns query results to the
     client. This includes result data such as column values, and
     result metadata such as column names.

Clients can fine-tune the settings for these variables, or depend on
the defaults (in which case, you can skip the rest of this section). If
you do not use the defaults, you must change the character settings
_for each connection to the server._

Two statements affect the connection-related character set variables as
a group:

   * `SET NAMES 'CHARSET_NAME' [COLLATE 'COLLATION_NAME']'

     `SET NAMES' indicates what character set the client will use to
     send SQL statements to the server.  Thus, `SET NAMES 'cp1251''
     tells the server, `future incoming messages from this client are
     in character set `cp1251'.' It also specifies the character set
     that the server should use for sending results back to the client.
     (For example, it indicates what character set to use for column
     values if you use a *Note `SELECT': select. statement.)

     A `SET NAMES 'X'' statement is equivalent to these three
     statements:

          SET character_set_client = X;
          SET character_set_results = X;
          SET character_set_connection = X;

     Setting `character_set_connection' to X also implicitly sets
     `collation_connection' to the default collation for X. It is
     unnecessary to set that collation explicitly. To specify a
     particular collation, use the optional `COLLATE' clause:

          SET NAMES 'CHARSET_NAME' COLLATE 'COLLATION_NAME'

   * `SET CHARACTER SET CHARSET_NAME'

     `SET CHARACTER SET' is similar to `SET NAMES' but sets
     `character_set_connection' and `collation_connection' to
     `character_set_database' and `collation_database'. A `SET
     CHARACTER SET X' statement is equivalent to these three statements:

          SET character_set_client = X;
          SET character_set_results = X;
          SET collation_connection = @@collation_database;

     Setting `collation_connection' also implicitly sets
     `character_set_connection' to the character set associated with
     the collation (equivalent to executing `SET
     character_set_connection = @@character_set_database'). It is
     unnecessary to set `character_set_connection' explicitly.

*Note*:

`ucs2' cannot be used as a client character set, which means that it
does not work for `SET NAMES' or `SET CHARACTER SET'.

The MySQL client programs `mysql', `mysqladmin', `mysqlcheck',
`mysqlimport', and `mysqlshow' determine the default character set to
use as follows:

   * In the absence of other information, the programs use the
     compiled-in default character set, usually `latin1'.

   * The programs support a `--default-character-set' option, which
     enables users to specify the character set explicitly to override
     whatever default the client otherwise determines.

When a client connects to the server, it sends the name of the
character set that it wants to use. The server uses the name to set the
`character_set_client', `character_set_results', and
`character_set_connection' system variables. In effect, the server
performs a `SET NAMES' operation using the character set name.

With the *Note `mysql': mysql. client, if you want to use a character
set different from the default, you could explicitly execute `SET
NAMES' every time you start up.  However, to accomplish the same result
more easily, you can add the `--default-character-set' option setting
to your *Note `mysql': mysql. command line or in your option file. For
example, the following option file setting changes the three
connection-related character set variables set to `koi8r' each time you
invoke *Note `mysql': mysql.:

     [mysql]
     default-character-set=koi8r

If you are using the *Note `mysql': mysql. client with auto-reconnect
enabled (which is not recommended), it is preferable to use the
`charset' command rather than `SET NAMES'. For example:

     mysql> charset utf8
     Charset changed

The `charset' command issues a `SET NAMES' statement, and also changes
the default character set that *Note `mysql': mysql. uses when it
reconnects after the connection has dropped.

Example: Suppose that `column1' is defined as `CHAR(5) CHARACTER SET
latin2'. If you do not say `SET NAMES' or `SET CHARACTER SET', then for
`SELECT column1 FROM t', the server sends back all the values for
`column1' using the character set that the client specified when it
connected. On the other hand, if you say `SET NAMES 'latin1'' or `SET
CHARACTER SET latin1' before issuing the *Note `SELECT': select.
statement, the server converts the `latin2' values to `latin1' just
before sending results back.  Conversion may be lossy if there are
characters that are not in both character sets.

If you do not want the server to perform any conversion of result sets
or error messages, set `character_set_results' to `NULL' or `binary':

     SET character_set_results = NULL;

To see the values of the character set and collation system variables
that apply to your connection, use these statements:

     SHOW VARIABLES LIKE 'character_set%';
     SHOW VARIABLES LIKE 'collation%';

You must also consider the environment within which your MySQL
applications execute. See *Note charset-applications::.

For more information about character sets and error messages, see *Note
charset-errors::.


File: manual.info,  Node: charset-applications,  Next: charset-errors,  Prev: charset-connection,  Up: charset

10.1.5 Configuring the Character Set and Collation for Applications
-------------------------------------------------------------------

For applications that store data using the default MySQL character set
and collation (`latin1', `latin1_swedish_ci'), no special configuration
should be needed. If applications require data storage using a
different character set or collation, you can configure character set
information several ways:

   * Specify character settings per database. For example, applications
     that use one database might require `utf8', whereas applications
     that use another database might require `sjis'.

   * Specify character settings at server startup. This causes the
     server to use the given settings for all applications that do not
     make other arrangements.

   * Specify character settings at configuration time, if you build
     MySQL from source. This causes the server to use the given
     settings for all applications, without having to specify them at
     server startup.

When different applications require different character settings, the
per-database technique provides a good deal of flexibility. If most or
all applications use the same character set, specifying character
settings at server startup or configuration time may be most convenient.

For the per-database or server-startup techniques, the settings control
the character set for data storage. Applications must also tell the
server which character set to use for client/server communications, as
described in the following instructions.

The examples shown here assume use of the `utf8' character set and
`utf8_general_ci' collation.

*Specify character settings per database.* To create a database such
that its tables will use a given default character set and collation
for data storage, use a *Note `CREATE DATABASE': create-database.
statement like this:

     CREATE DATABASE mydb
       DEFAULT CHARACTER SET utf8
       DEFAULT COLLATE utf8_general_ci;

Tables created in the database will use `utf8' and `utf8_general_ci' by
default for any character columns.

Applications that use the database should also configure their
connection to the server each time they connect. This can be done by
executing a `SET NAMES 'utf8'' statement after connecting. The
statement can be used regardless of connection method: The *Note
`mysql': mysql. client, PHP scripts, and so forth.

In some cases, it may be possible to configure the connection to use
the desired character set some other way. For example, for connections
made using *Note `mysql': mysql, you can specify the
`--default-character-set=utf8' command-line option to achieve the same
effect as `SET NAMES 'utf8''.

For more information about configuring client connections, see *Note
charset-connection::.

If you change the default character set or collation for a database,
stored routines that use the database defaults must be dropped and
recreated so that they use the new defaults. (In a stored routine,
variables with character data types use the database defaults if the
character set or collation are not specified explicitly. See *Note
create-procedure::.)

*Specify character settings at server startup.* To select a character
set and collation at server startup, use the `--character-set-server'
and `--collation-server' options. For example, to specify the options
in an option file, include these lines:

     [mysqld]
     character-set-server=utf8
     collation-server=utf8_general_ci

These settings apply server-wide and apply as the defaults for
databases created by any application, and for tables created in those
databases.

It is still necessary for applications to configure their connection
using `SET NAMES' or equivalent after they connect, as described
previously. You might be tempted to start the server with the
`--init_connect="SET NAMES 'utf8'"' option to cause `SET NAMES' to be
executed automatically for each client that connects. However, this will
yield inconsistent results because the `init_connect' value is not
executed for users who have the `SUPER' privilege.

*Specify character settings at MySQL configuration time.* To select a
character set and collation when you configure and build MySQL from
source, use the `--with-charset' and `--with-collation' options:

     shell> ./configure --with-charset=utf8 --with-collation=utf8_general_ci

The resulting server uses `utf8' and `utf8_general_ci' as the default
for databases and tables and for client connections. It is unnecessary
to use `--character-set-server' and `--collation-server' to specify
those defaults at server startup. It is also unnecessary for
applications to configure their connection using `SET NAMES' or
equivalent after they connect to the server.

Regardless of how you configure the MySQL character set for application
use, you must also consider the environment within which those
applications execute. If you will send statements using UTF-8 text
taken from a file that you create in an editor, you should edit the
file with the locale of your environment set to UTF-8 so that the file
encoding is correct and so that the operating system handles it
correctly. If you use the *Note `mysql': mysql. client from within a
terminal window, the window must be configured to use UTF-8 or
characters may not display properly. For a script that executes in a Web
environment, the script must handle character encoding properly for its
interaction with the MySQL server, and it must generate pages that
correctly indicate the encoding so that browsers know how to display
the content of the pages. For example, you can include this `<meta>'
tag within your `<head>' element:

     <meta http-equiv="Content-Type" content="text/html; charset=utf-8" />


File: manual.info,  Node: charset-errors,  Next: charset-collations,  Prev: charset-applications,  Up: charset

10.1.6 Character Set for Error Messages
---------------------------------------

This section describes how the server uses character sets for
constructing error messages and returning them to clients. For
information about the language of error messages (rather than the
character set), see *Note error-message-language::.

In MySQL 5.0, the server constructs error messages and returns them to
clients as follows:

   * The message template has the character set associated with the
     error message language. For example, English, Korean, and Russian
     messages use `latin1', `euckr', and `koi8r', respectively.

   * Parameters in the message template are replaced with values that
     apply to a specific error occurrence. These parameters use their
     own character set. Identifiers such as table or column names use
     UTF-8. Data values retain their character set. For example, in the
     following duplicate-key message, `'XXX'' has the character set of
     the table column associated with key 1:

          Duplicate entry 'XXX' for key1

The preceding method of error-message construction can result in
messages that contain a mix of character sets unless all items involved
contain only ASCII characters. This issue is resolved in MySQL 5.5, in
which error messages are constructed internally within the server using
UTF-8 and returned to the client in the character set specified by the
`character_set_results' system variable.


File: manual.info,  Node: charset-collations,  Next: charset-repertoire,  Prev: charset-errors,  Up: charset

10.1.7 Collation Issues
-----------------------

* Menu:

* charset-collation-names::      Collation Names
* charset-collate::              Using `COLLATE' in SQL Statements
* charset-collate-precedence::   `COLLATE' Clause Precedence
* charset-collation-charset::    Collations Must Be for the Right Character Set
* charset-collation-expressions::  Collation of Expressions
* charset-binary-collations::    The `_bin' and `binary' Collations
* charset-binary-op::            The `BINARY' Operator
* charset-collation-effect::     Examples of the Effect of Collation

The following sections discuss various aspects of character set
collations.


File: manual.info,  Node: charset-collation-names,  Next: charset-collate,  Prev: charset-collations,  Up: charset-collations

10.1.7.1 Collation Names
........................

MySQL collation names follow these rules:

   * A name ending in `_ci' indicates a case-insensitive collation.

   * A name ending in `_cs' indicates a case-sensitive collation.

   * A name ending in `_bin' indicates a binary collation. Character
     comparisons are based on character binary code values.


File: manual.info,  Node: charset-collate,  Next: charset-collate-precedence,  Prev: charset-collation-names,  Up: charset-collations

10.1.7.2 Using `COLLATE' in SQL Statements
..........................................

With the `COLLATE' clause, you can override whatever the default
collation is for a comparison.  `COLLATE' may be used in various parts
of SQL statements. Here are some examples:

   * With `ORDER BY':

          SELECT k
          FROM t1
          ORDER BY k COLLATE latin1_german2_ci;

   * With `AS':

          SELECT k COLLATE latin1_german2_ci AS k1
          FROM t1
          ORDER BY k1;

   * With `GROUP BY':

          SELECT k
          FROM t1
          GROUP BY k COLLATE latin1_german2_ci;

   * With aggregate functions:

          SELECT MAX(k COLLATE latin1_german2_ci)
          FROM t1;

   * With `DISTINCT':

          SELECT DISTINCT k COLLATE latin1_german2_ci
          FROM t1;

   * With `WHERE':

               SELECT *
               FROM t1
               WHERE _latin1 'Mu"ller' COLLATE latin1_german2_ci = k;

               SELECT *
               FROM t1
               WHERE k LIKE _latin1 'Mu"ller' COLLATE latin1_german2_ci;

   * With `HAVING':

          SELECT k
          FROM t1
          GROUP BY k
          HAVING k = _latin1 'Mu"ller' COLLATE latin1_german2_ci;


File: manual.info,  Node: charset-collate-precedence,  Next: charset-collation-charset,  Prev: charset-collate,  Up: charset-collations

10.1.7.3 `COLLATE' Clause Precedence
....................................

The `COLLATE' clause has high precedence (higher than `||'), so the
following two expressions are equivalent:

     x || y COLLATE z
     x || (y COLLATE z)


File: manual.info,  Node: charset-collation-charset,  Next: charset-collation-expressions,  Prev: charset-collate-precedence,  Up: charset-collations

10.1.7.4 Collations Must Be for the Right Character Set
.......................................................

Each character set has one or more collations, but each collation is
associated with one and only one character set.  Therefore, the
following statement causes an error message because the `latin2_bin'
collation is not legal with the `latin1' character set:

     mysql> SELECT _latin1 'x' COLLATE latin2_bin;
     ERROR 1253 (42000): COLLATION 'latin2_bin' is not valid
     for CHARACTER SET 'latin1'


File: manual.info,  Node: charset-collation-expressions,  Next: charset-binary-collations,  Prev: charset-collation-charset,  Up: charset-collations

10.1.7.5 Collation of Expressions
.................................

In the great majority of statements, it is obvious what collation MySQL
uses to resolve a comparison operation. For example, in the following
cases, it should be clear that the collation is the collation of column
`x':

     SELECT x FROM T ORDER BY x;
     SELECT x FROM T WHERE x = x;
     SELECT DISTINCT x FROM T;

However, with multiple operands, there can be ambiguity. For example:

     SELECT x FROM T WHERE x = 'Y';

Should the comparison use the collation of the column `x', or of the
string literal `'Y''? Both `x' and `'Y'' have collations, so which
collation takes precedence?

Standard SQL resolves such questions using what used to be called
`coercibility' rules. MySQL assigns coercibility values as follows:

   * An explicit `COLLATE' clause has a coercibility of 0. (Not
     coercible at all.)

   * The concatenation of two strings with different collations has a
     coercibility of 1.

   * The collation of a column or a stored routine parameter or local
     variable has a coercibility of 2.

   * A `system constant' (the string returned by functions such as
     `USER()' or `VERSION()') has a coercibility of 3.

   * The collation of a literal has a coercibility of 4.

   * `NULL' or an expression that is derived from `NULL' has a
     coercibility of 5.

The preceding coercibility values are current as of MySQL 5.0.3. In
MySQL 5.0 prior to 5.0.3, there is no system constant or `NULL'
coercibility.  Functions such as `USER()' have a coercibility of 2
rather than 3, and literals have a coercibility of 3 rather than 4.

MySQL uses coercibility values with the following rules to resolve
ambiguities:

   * Use the collation with the lowest coercibility value.

   * If both sides have the same coercibility, then:

        * If both sides are Unicode, or both sides are not Unicode, it
          is an error.

        * If one of the sides has a Unicode character set, and another
          side has a non-Unicode character set, the side with Unicode
          character set wins, and automatic character set conversion is
          applied to the non-Unicode side. For example, the following
          statement does not return an error:

               SELECT CONCAT(utf8_column, latin1_column) FROM t1;

          It returns a result that has a character set of `utf8' and
          the same collation as `utf8_column'. Values of
          `latin1_column' are automatically converted to `utf8' before
          concatenating.

        * For an operation with operands from the same character set
          but that mix a `_bin' collation and a `_ci' or `_cs'
          collation, the `_bin' collation is used. This is similar to
          how operations that mix nonbinary and binary strings evaluate
          the operands as binary strings, except that it is for
          collations rather than data types.

Although automatic conversion is not in the SQL standard, the SQL
standard document does say that every character set is (in terms of
supported characters) a `subset' of Unicode. Because it is a well-known
principle that `what applies to a superset can apply to a subset,' we
believe that a collation for Unicode can apply for comparisons with
non-Unicode strings.

Examples:

Comparison                           Collation Used
`column1 = 'A''                      Use collation of `column1'
`column1 = 'A' COLLATE x'            Use collation of `'A' COLLATE x'
`column1 COLLATE x = 'A' COLLATE y'  Error

The `COERCIBILITY()' function can be used to determine the coercibility
of a string expression:

     mysql> SELECT COERCIBILITY('A' COLLATE latin1_swedish_ci);
             -> 0
     mysql> SELECT COERCIBILITY(VERSION());
             -> 3
     mysql> SELECT COERCIBILITY('A');
             -> 4

See *Note information-functions::.

For implicit conversion of a numeric or temporal value to a string,
such as occurs for the argument `1' in the expression `CONCAT(1,
'abc')', the result is a binary string for which the character set and
collation are `binary'. See *Note type-conversion::.


File: manual.info,  Node: charset-binary-collations,  Next: charset-binary-op,  Prev: charset-collation-expressions,  Up: charset-collations

10.1.7.6 The `_bin' and `binary' Collations
...........................................

This section describes how `_bin' collations for nonbinary strings
differ from the `binary' `collation' for binary strings.

Nonbinary strings (as stored in the *Note `CHAR': char, *Note
`VARCHAR': char, and *Note `TEXT': blob. data types) have a character
set and collation. A given character set can have several collations,
each of which defines a particular sorting and comparison order for the
characters in the set. One of these is the binary collation for the
character set, indicated by a `_bin' suffix in the collation name. For
example, `latin1' and `utf8' have binary collations named `latin1_bin'
and `utf8_bin'.

Binary strings (as stored in the *Note `BINARY': binary-varbinary,
*Note `VARBINARY': binary-varbinary, and *Note `BLOB': blob. data
types) have no character set or collation in the sense that nonbinary
strings do. (Applied to a binary string, the `CHARSET()' and
`COLLATION()' functions both return a value of `binary'.) Binary
strings are sequences of bytes and the numeric values of those bytes
determine sort order.

The `_bin' collations differ from the `binary' collation in several
respects.

*The unit for sorting and comparison.* Binary strings are sequences of
bytes.  Sorting and comparison is always based on numeric byte values.
Nonbinary strings are sequences of characters, which might be
multi-byte. Collations for nonbinary strings define an ordering of the
character values for sorting and comparison.  For the `_bin' collation,
this ordering is based solely on binary code values of the characters
(which is similar to ordering for binary strings except that a `_bin'
collation must take into account that a character might contain
multiple bytes). For other collations, character ordering might take
additional factors such as lettercase into account.

*Character set conversion.* A nonbinary string has a character set and
is converted to another character set in many cases, even when the
string has a `_bin' collation:

   * When assigning column values from another column that has a
     different character set:

          UPDATE t1 SET utf8_bin_column=latin1_column;
          INSERT INTO t1 (latin1_column) SELECT utf8_bin_column FROM t2;

   * When assigning column values for *Note `INSERT': insert. or *Note
     `UPDATE': update. using a string literal:

          SET NAMES latin1;
          INSERT INTO t1 (utf8_bin_column) VALUES ('string-in-latin1');

   * When sending results from the server to a client:

          SET NAMES latin1;
          SELECT utf8_bin_column FROM t2;

For binary string columns, no conversion occurs. For the preceding
cases, the string value is copied byte-wise.

*Lettercase conversion.* Collations provide information about
lettercase of characters, so characters in a nonbinary string can be
converted from one lettercase to another, even for `_bin' collations
that ignore lettercase for ordering:

     mysql> SET NAMES latin1 COLLATE latin1_bin;
     Query OK, 0 rows affected (0.02 sec)

     mysql> SELECT LOWER('aA'), UPPER('zZ');
     +-------------+-------------+
     | LOWER('aA') | UPPER('zZ') |
     +-------------+-------------+
     | aa          | ZZ          |
     +-------------+-------------+
     1 row in set (0.13 sec)

The concept of lettercase does not apply to bytes in a binary string.
To perform lettercase conversion, the string must be converted to a
nonbinary string:

     mysql> SET NAMES binary;
     Query OK, 0 rows affected (0.00 sec)

     mysql> SELECT LOWER('aA'), LOWER(CONVERT('aA' USING latin1));
     +-------------+-----------------------------------+
     | LOWER('aA') | LOWER(CONVERT('aA' USING latin1)) |
     +-------------+-----------------------------------+
     | aA          | aa                                |
     +-------------+-----------------------------------+
     1 row in set (0.00 sec)

*Trailing space handling in comparisons.* Nonbinary strings have
`PADSPACE' behavior for all collations, including `_bin' collations.
Trailing spaces are insignificant in comparisons:

     mysql> SET NAMES utf8 COLLATE utf8_bin;
     Query OK, 0 rows affected (0.00 sec)

     mysql> SELECT 'a ' = 'a';
     +------------+
     | 'a ' = 'a' |
     +------------+
     |          1 |
     +------------+
     1 row in set (0.00 sec)

For binary strings, all characters are significant in comparisons,
including trailing spaces:

     mysql> SET NAMES binary;
     Query OK, 0 rows affected (0.00 sec)

     mysql> SELECT 'a ' = 'a';
     +------------+
     | 'a ' = 'a' |
     +------------+
     |          0 |
     +------------+
     1 row in set (0.00 sec)

*Trailing space handling for inserts and retrievals.* `CHAR(N)' columns
store nonbinary strings. Values shorter than N characters are extended
with spaces on insertion. For retrieval, trailing spaces are removed.

`BINARY(N)' columns store binary strings. Values shorter than N bytes
are extended with `0x00' bytes on insertion. For retrieval, nothing is
removed; a value of the declared length is always returned.

     mysql> CREATE TABLE t1 (
         ->   a CHAR(10) CHARACTER SET utf8 COLLATE utf8_bin,
         ->   b BINARY(10)
         -> );
     Query OK, 0 rows affected (0.09 sec)

     mysql> INSERT INTO t1 VALUES ('a','a');
     Query OK, 1 row affected (0.01 sec)

     mysql> SELECT HEX(a), HEX(b) FROM t1;
     +--------+----------------------+
     | HEX(a) | HEX(b)               |
     +--------+----------------------+
     | 61     | 61000000000000000000 |
     +--------+----------------------+
     1 row in set (0.04 sec)


File: manual.info,  Node: charset-binary-op,  Next: charset-collation-effect,  Prev: charset-binary-collations,  Up: charset-collations

10.1.7.7 The `BINARY' Operator
..............................

The `BINARY' operator casts the string following it to a binary string.
This is an easy way to force a comparison to be done byte by byte
rather than character by character. `BINARY' also causes trailing
spaces to be significant.

     mysql> SELECT 'a' = 'A';
             -> 1
     mysql> SELECT BINARY 'a' = 'A';
             -> 0
     mysql> SELECT 'a' = 'a ';
             -> 1
     mysql> SELECT BINARY 'a' = 'a ';
             -> 0

`BINARY STR' is shorthand for `CAST(STR AS BINARY)'.

The `BINARY' attribute in character column definitions has a different
effect. A character column defined with the `BINARY' attribute is
assigned the binary collation of the column character set. Every
character set has a binary collation. For example, the binary collation
for the `latin1' character set is `latin1_bin', so if the table default
character set is `latin1', these two column definitions are equivalent:

     CHAR(10) BINARY
     CHAR(10) CHARACTER SET latin1 COLLATE latin1_bin

The effect of `BINARY' as a column attribute differs from its effect
prior to MySQL 4.1. Formerly, `BINARY' resulted in a column that was
treated as a binary string. A binary string is a string of bytes that
has no character set or collation, which differs from a nonbinary
character string that has a binary collation.  For both types of
strings, comparisons are based on the numeric values of the string
unit, but for nonbinary strings the unit is the character and some
character sets support multi-byte characters. *Note binary-varbinary::.

The use of `CHARACTER SET binary' in the definition of a *Note `CHAR':
char, *Note `VARCHAR': char, or *Note `TEXT': blob. column causes the
column to be treated as a binary data type. For example, the following
pairs of definitions are equivalent:

     CHAR(10) CHARACTER SET binary
     BINARY(10)

     VARCHAR(10) CHARACTER SET binary
     VARBINARY(10)

     TEXT CHARACTER SET binary
     BLOB


File: manual.info,  Node: charset-collation-effect,  Prev: charset-binary-op,  Up: charset-collations

10.1.7.8 Examples of the Effect of Collation
............................................

*Example 1: Sorting German Umlauts*

Suppose that column `X' in table `T' has these `latin1' column values:

     Muffler
     Mu"ller
     MX Systems
     MySQL

Suppose also that the column values are retrieved using the following
statement:

     SELECT X FROM T ORDER BY X COLLATE COLLATION_NAME;

The following table shows the resulting order of the values if we use
`ORDER BY' with different collations.

`latin1_swedish_ci'    `latin1_german1_ci'    `latin1_german2_ci'
Muffler                Muffler                Mu"ller
MX Systems             Mu"ller                Muffler
Mu"ller                MX Systems             MX Systems
MySQL                  MySQL                  MySQL

The character that causes the different sort orders in this example is
the U with two dots over it (`u"'), which the Germans call `U-umlaut.'

   * The first column shows the result of the *Note `SELECT': select.
     using the Swedish/Finnish collating rule, which says that U-umlaut
     sorts with Y.

   * The second column shows the result of the *Note `SELECT': select.
     using the German DIN-1 rule, which says that U-umlaut sorts with U.

   * The third column shows the result of the *Note `SELECT': select.
     using the German DIN-2 rule, which says that U-umlaut sorts with
     UE.

*Example 2: Searching for German Umlauts*

Suppose that you have three tables that differ only by the character
set and collation used:

     mysql> SET NAMES utf8;
     mysql> CREATE TABLE german1 (
         ->   c CHAR(10)
         -> ) CHARACTER SET latin1 COLLATE latin1_german1_ci;
     mysql> CREATE TABLE german2 (
         ->   c CHAR(10)
         -> ) CHARACTER SET latin1 COLLATE latin1_german2_ci;
     mysql> CREATE TABLE germanutf8 (
         ->   c CHAR(10)
         -> ) CHARACTER SET utf8 COLLATE utf8_unicode_ci;

Each table contains two records:

     mysql> INSERT INTO german1 VALUES ('Bar'), ('Ba"r');
     mysql> INSERT INTO german2 VALUES ('Bar'), ('Ba"r');
     mysql> INSERT INTO germanutf8 VALUES ('Bar'), ('Ba"r');

Two of the above collations have an `A = A"' equality, and one has no
such equality (`latin1_german2_ci'). For that reason, you'll get these
results in comparisons:

     mysql> SELECT * FROM german1 WHERE c = 'Ba"r';
     +------+
     | c    |
     +------+
     | Bar  |
     | Ba"r  |
     +------+
     mysql> SELECT * FROM german2 WHERE c = 'Ba"r';
     +------+
     | c    |
     +------+
     | Ba"r  |
     +------+
     mysql> SELECT * FROM germanutf8 WHERE c = 'Ba"r';
     +------+
     | c    |
     +------+
     | Bar  |
     | Ba"r  |
     +------+

This is not a bug but rather a consequence of the sorting properties of
`latin1_german1_ci' and `utf8_unicode_ci' (the sorting shown is done
according to the German DIN 5007 standard).


File: manual.info,  Node: charset-repertoire,  Next: charset-operations,  Prev: charset-collations,  Up: charset

10.1.8 String Repertoire
------------------------

The _repertoire_ of a character set is the collection of characters in
the set.

As of MySQL 5.0.48, string expressions have a repertoire attribute,
which can have two values:

   * `ASCII': The expression can contain only characters in the Unicode
     range `U+0000' to `U+007F'.

   * `UNICODE': The expression can contain characters in the Unicode
     range `U+0000' to `U+FFFF'.

The `ASCII' range is a subset of `UNICODE' range, so a string with
`ASCII' repertoire can be converted safely without loss of information
to the character set of any string with `UNICODE' repertoire or to a
character set that is a superset of `ASCII'. (All MySQL character sets
are supersets of `ASCII' with the exception of `swe7', which reuses some
punctuation characters for Swedish accented characters.) The use of
repertoire enables character set conversion in expressions for many
cases where MySQL would otherwise return an `illegal mix of collations'
error.

The following discussion provides examples of expressions and their
repertoires, and describes how the use of repertoire changes string
expression evaluation:

   * The repertoire for string constants depends on string content:

          SET NAMES utf8; SELECT 'abc';
          SELECT _utf8'def';
          SELECT N'MySQL';

     Although the character set is `utf8' in each of the preceding
     cases, the strings do not actually contain any characters outside
     the ASCII range, so their repertoire is `ASCII' rather than
     `UNICODE'.

   * Columns having the `ascii' character set have `ASCII' repertoire
     because of their character set. In the following table, `c1' has
     `ASCII' repertoire:

          CREATE TABLE t1 (c1 CHAR(1) CHARACTER SET ascii);

     The following example illustrates how repertoire enables a result
     to be determined in a case where an error occurs without
     repertoire:

          CREATE TABLE t1 (
            c1 CHAR(1) CHARACTER SET latin1,
            c2 CHAR(1) CHARACTER SET ascii
          );
          INSERT INTO t1 VALUES ('a','b');
          SELECT CONCAT(c1,c2) FROM t1;

     Without repertoire, this error occurs:

          ERROR 1267 (HY000): Illegal mix of collations (latin1_swedish_ci,IMPLICIT)
          and (ascii_general_ci,IMPLICIT) for operation 'concat'

     Using repertoire, subset to superset (`ascii' to `latin1')
     conversion can occur and a result is returned:

          +---------------+
          | CONCAT(c1,c2) |
          +---------------+
          | ab            |
          +---------------+

   * Functions with one string argument inherit the repertoire of their
     argument. The result of `UPPER(_utf8'ABC')' has `ASCII'
     repertoire, because its argument has `ASCII' repertoire.

   * For functions that return a string but do not have string
     arguments and use `character_set_connection' as the result
     character set, the result repertoire is `ASCII' if
     `character_set_connection' is `ascii', and `UNICODE' otherwise:

          FORMAT(NUMERIC_COLUMN, 4);

     Use of repertoire changes how MySQL evaluates the following
     example:

          SET NAMES ascii;
          CREATE TABLE t1 (a INT, b VARCHAR(10) CHARACTER SET latin1);
          INSERT INTO t1 VALUES (1,'b');
          SELECT CONCAT(FORMAT(a, 4), b) FROM t1;

     Without repertoire, this error occurs:

          ERROR 1267 (HY000): Illegal mix of collations (ascii_general_ci,COERCIBLE)
          and (latin1_swedish_ci,IMPLICIT) for operation 'concat'

     With repertoire, a result is returned:

          +-------------------------+
          | CONCAT(FORMAT(a, 4), b) |
          +-------------------------+
          | 1.0000b                 |
          +-------------------------+

   * Functions with two or more string arguments use the `widest'
     argument repertoire for the result repertoire (`UNICODE' is wider
     than `ASCII'). Consider the following `CONCAT()' calls:

          CONCAT(_ucs2 0x0041, _ucs2 0x0042)
          CONCAT(_ucs2 0x0041, _ucs2 0x00C2)

     For the first call, the repertoire is `ASCII' because both
     arguments are within the range of the `ascii' character set. For
     the second call, the repertoire is `UNICODE' because the second
     argument is outside the `ascii' character set range.

   * The repertoire for function return values is determined based only
     on the repertoire of the arguments that affect the result's
     character set and collation.

          IF(column1 < column2, 'smaller', 'greater')

     The result repertoire is `ASCII' because the two string arguments
     (the second argument and the third argument) both have `ASCII'
     repertoire. The first argument does not matter for the result
     repertoire, even if the expression uses string values.


File: manual.info,  Node: charset-operations,  Next: charset-unicode,  Prev: charset-repertoire,  Up: charset

10.1.9 Operations Affected by Character Set Support
---------------------------------------------------

* Menu:

* charset-result::               Result Strings
* charset-convert::              `CONVERT()' and `CAST()'
* charset-show::                 `SHOW' Statements and `INFORMATION_SCHEMA'

This section describes operations that take character set information
into account.


File: manual.info,  Node: charset-result,  Next: charset-convert,  Prev: charset-operations,  Up: charset-operations

10.1.9.1 Result Strings
.......................

MySQL has many operators and functions that return a string.  This
section answers the question: What is the character set and collation
of such a string?

For simple functions that take string input and return a string result
as output, the output's character set and collation are the same as
those of the principal input value.  For example, `UPPER(X)' returns a
string whose character string and collation are the same as that of X.
The same applies for `INSTR()', `LCASE()', `LOWER()', `LTRIM()',
`MID()', `REPEAT()', `REPLACE()', `REVERSE()', `RIGHT()', `RPAD()',
`RTRIM()', `SOUNDEX()', `SUBSTRING()', `TRIM()', `UCASE()', and
`UPPER()'.

Note: The `REPLACE()' function, unlike all other functions, always
ignores the collation of the string input and performs a case-sensitive
comparison.

If a string input or function result is a binary string, the string has
no character set or collation. This can be checked by using the
`CHARSET()' and `COLLATION()' functions, both of which return `binary'
to indicate that their argument is a binary string:

     mysql> SELECT CHARSET(BINARY 'a'), COLLATION(BINARY 'a');
     +---------------------+-----------------------+
     | CHARSET(BINARY 'a') | COLLATION(BINARY 'a') |
     +---------------------+-----------------------+
     | binary              | binary                |
     +---------------------+-----------------------+

For operations that combine multiple string inputs and return a single
string output, the `aggregation rules' of standard SQL apply for
determining the collation of the result:

   * If an explicit `COLLATE X' occurs, use X.

   * If explicit `COLLATE X' and `COLLATE Y' occur, raise an error.

   * Otherwise, if all collations are X, use X.

   * Otherwise, the result has no collation.

For example, with `CASE ... WHEN a THEN b WHEN b THEN c COLLATE X END',
the resulting collation is X. The same applies for *Note `UNION': union,
`||', `CONCAT()', `ELT()', `GREATEST()', `IF()', and `LEAST()'.

For operations that convert to character data, the character set and
collation of the strings that result from the operations are defined by
the `character_set_connection' and `collation_connection' system
variables. This applies only to `CAST()', `CONV()', `FORMAT()', `HEX()',
`SPACE()'. Before MySQL 5.0.15, it also applies to `CHAR()'.

If you are uncertain about the character set or collation of the result
returned by a string function, you can use the `CHARSET()' or
`COLLATION()' function to find out:

     mysql> SELECT USER(), CHARSET(USER()), COLLATION(USER());
     +----------------+-----------------+-------------------+
     | USER()         | CHARSET(USER()) | COLLATION(USER()) |
     +----------------+-----------------+-------------------+
     | test@localhost | utf8            | utf8_general_ci   |
     +----------------+-----------------+-------------------+


File: manual.info,  Node: charset-convert,  Next: charset-show,  Prev: charset-result,  Up: charset-operations

10.1.9.2 `CONVERT()' and `CAST()'
.................................

`CONVERT()' provides a way to convert data between different character
sets. The syntax is:

     CONVERT(EXPR USING TRANSCODING_NAME)

In MySQL, transcoding names are the same as the corresponding character
set names.

Examples:

     SELECT CONVERT(_latin1'Mu"ller' USING utf8);
     INSERT INTO utf8table (utf8column)
         SELECT CONVERT(latin1field USING utf8) FROM latin1table;

`CONVERT(... USING ...)' is implemented according to the standard SQL
specification.

You may also use `CAST()' to convert a string to a different character
set. The syntax is:

     CAST(CHARACTER_STRING AS CHARACTER_DATA_TYPE CHARACTER SET CHARSET_NAME)

Example:

     SELECT CAST(_latin1'test' AS CHAR CHARACTER SET utf8);

If you use `CAST()' without specifying `CHARACTER SET', the resulting
character set and collation are defined by the
`character_set_connection' and `collation_connection' system variables.
If you use `CAST()' with `CHARACTER SET X', the resulting character set
and collation are `X' and the default collation of `X'.

You may not use a `COLLATE' clause inside a `CONVERT()' or `CAST()'
call, but you may use it outside. For example, `CAST(... COLLATE ...)'
is illegal, but `CAST(...)  COLLATE ...' is legal:

     SELECT CAST(_latin1'test' AS CHAR CHARACTER SET utf8) COLLATE utf8_bin;


File: manual.info,  Node: charset-show,  Prev: charset-convert,  Up: charset-operations

10.1.9.3 `SHOW' Statements and `INFORMATION_SCHEMA'
...................................................

Several *Note `SHOW': show. statements provide additional character set
information. These include *Note `SHOW CHARACTER SET':
show-character-set, *Note `SHOW COLLATION': show-collation, *Note `SHOW
CREATE DATABASE': show-create-database, *Note `SHOW CREATE TABLE':
show-create-table. and *Note `SHOW COLUMNS': show-columns. These
statements are described here briefly. For more information, see *Note
show::.

`INFORMATION_SCHEMA' has several tables that contain information
similar to that displayed by the *Note `SHOW': show. statements. For
example, the *Note `CHARACTER_SETS': character-sets-table. and *Note
`COLLATIONS': collations-table. tables contain the information
displayed by *Note `SHOW CHARACTER SET': show-character-set. and *Note
`SHOW COLLATION': show-collation. See *Note information-schema::.

The *Note `SHOW CHARACTER SET': show-character-set.  statement shows
all available character sets. It takes an optional `LIKE' clause that
indicates which character set names to match. For example:

     mysql> SHOW CHARACTER SET LIKE 'latin%';
     +---------+-----------------------------+-------------------+--------+
     | Charset | Description                 | Default collation | Maxlen |
     +---------+-----------------------------+-------------------+--------+
     | latin1  | cp1252 West European        | latin1_swedish_ci |      1 |
     | latin2  | ISO 8859-2 Central European | latin2_general_ci |      1 |
     | latin5  | ISO 8859-9 Turkish          | latin5_turkish_ci |      1 |
     | latin7  | ISO 8859-13 Baltic          | latin7_general_ci |      1 |
     +---------+-----------------------------+-------------------+--------+

The output from *Note `SHOW COLLATION': show-collation.  includes all
available character sets. It takes an optional `LIKE' clause that
indicates which collation names to match. For example:

     mysql> SHOW COLLATION LIKE 'latin1%';
     +-------------------+---------+----+---------+----------+---------+
     | Collation         | Charset | Id | Default | Compiled | Sortlen |
     +-------------------+---------+----+---------+----------+---------+
     | latin1_german1_ci | latin1  |  5 |         |          |       0 |
     | latin1_swedish_ci | latin1  |  8 | Yes     | Yes      |       0 |
     | latin1_danish_ci  | latin1  | 15 |         |          |       0 |
     | latin1_german2_ci | latin1  | 31 |         | Yes      |       2 |
     | latin1_bin        | latin1  | 47 |         | Yes      |       0 |
     | latin1_general_ci | latin1  | 48 |         |          |       0 |
     | latin1_general_cs | latin1  | 49 |         |          |       0 |
     | latin1_spanish_ci | latin1  | 94 |         |          |       0 |
     +-------------------+---------+----+---------+----------+---------+

*Note `SHOW CREATE DATABASE': show-create-database. displays the *Note
`CREATE DATABASE': create-database. statement that creates a given
database:

     mysql> SHOW CREATE DATABASE test;
     +----------+-----------------------------------------------------------------+
     | Database | Create Database                                                 |
     +----------+-----------------------------------------------------------------+
     | test     | CREATE DATABASE `test` /*!40100 DEFAULT CHARACTER SET latin1 */ |
     +----------+-----------------------------------------------------------------+

If no `COLLATE' clause is shown, the default collation for the
character set applies.

*Note `SHOW CREATE TABLE': show-create-table. is similar, but displays
the *Note `CREATE TABLE': create-table.  statement to create a given
table. The column definitions indicate any character set
specifications, and the table options include character set information.

The *Note `SHOW COLUMNS': show-columns. statement displays the
collations of a table's columns when invoked as *Note `SHOW FULL
COLUMNS': show-columns. Columns with *Note `CHAR': char, *Note
`VARCHAR': char, or *Note `TEXT': blob. data types have collations.
Numeric and other noncharacter types have no collation (indicated by
`NULL' as the `Collation' value). For example:

     mysql> SHOW FULL COLUMNS FROM person\G
     *************************** 1. row ***************************
          Field: id
           Type: smallint(5) unsigned
      Collation: NULL
           Null: NO
            Key: PRI
        Default: NULL
          Extra: auto_increment
     Privileges: select,insert,update,references
        Comment:
     *************************** 2. row ***************************
          Field: name
           Type: char(60)
      Collation: latin1_swedish_ci
           Null: NO
            Key:
        Default:
          Extra:
     Privileges: select,insert,update,references
        Comment:

The character set is not part of the display but is implied by the
collation name.


File: manual.info,  Node: charset-unicode,  Next: charset-metadata,  Prev: charset-operations,  Up: charset

10.1.10 Unicode Support
-----------------------

* Menu:

* charset-unicode-ucs2::         The `ucs2' Character Set (UCS-2 Unicode Encoding)
* charset-unicode-utf8::         The `utf8' Character Set (Three-Byte UTF-8 Unicode Encoding)

MySQL 5.0 supports two character sets for storing Unicode data:

   * `ucs2', the UCS-2 encoding of the Unicode character set using 16
     bits per character

   * `utf8', a UTF-8 encoding of the Unicode character set using one to
     three bytes per character

These two character sets support the characters from the Basic
Multilingual Plane (BMP) of Unicode Version 3.0. BMP characters have
these characteristics:

   * Their code values are between 0 and 65535 (or `U+0000' .. `U+FFFF')

   * They can be encoded with a fixed 16-bit word, as in `ucs2'

   * They can be encoded with 8, 16, or 24 bits, as in `utf8'

   * They are sufficient for almost all characters in major languages

The `ucs2' and `utf8' character sets do not support supplementary
characters that lie outside the BMP. Characters outside the BMP compare
as REPLACEMENT CHARACTER and convert to `'?'' when converted to a
Unicode character set.

A similar set of collations is available for each Unicode character
set. For example, each has a Danish collation, the names of which are
`ucs2_danish_ci' and `utf8_danish_ci'. All Unicode collations are
listed at *Note charset-unicode-sets::.

The MySQL implementation of UCS-2 stores characters in big-endian byte
order and does not use a byte order mark (BOM) at the beginning of
values. Other database systems might use little-endian byte order or a
BOM. In such cases, conversion of values will need to be performed when
transferring data between those systems and MySQL.

MySQL uses no BOM for UTF-8 values.

Client applications that need to communicate with the server using
Unicode should set the client character set accordingly; for example,
by issuing a `SET NAMES 'utf8'' statement. `ucs2' cannot be used as a
client character set, which means that it does not work for `SET NAMES'
or `SET CHARACTER SET'. (See *Note charset-connection::.)

The following sections provide additional detail on the Unicode
character sets in MySQL.


File: manual.info,  Node: charset-unicode-ucs2,  Next: charset-unicode-utf8,  Prev: charset-unicode,  Up: charset-unicode

10.1.10.1 The `ucs2' Character Set (UCS-2 Unicode Encoding)
...........................................................

In UCS-2, every character is represented by a two-byte Unicode code
with the most significant byte first. For example: `LATIN CAPITAL
LETTER A' has the code `0x0041' and it is stored as a two-byte
sequence: `0x00 0x41'. `CYRILLIC SMALL LETTER YERU' (Unicode `0x044B')
is stored as a two-byte sequence: `0x04 0x4B'. For Unicode characters
and their codes, please refer to the Unicode Home Page
(http://www.unicode.org/).

In MySQL, the `ucs2' character set is a fixed-length 16-bit encoding
for Unicode BMP characters.


File: manual.info,  Node: charset-unicode-utf8,  Prev: charset-unicode-ucs2,  Up: charset-unicode

10.1.10.2 The `utf8' Character Set (Three-Byte UTF-8 Unicode Encoding)
......................................................................

UTF-8 (Unicode Transformation Format with 8-bit units) is an
alternative way to store Unicode data. It is implemented according to
RFC 3629, which describes encoding sequences that take from one to four
bytes. Currently, MySQL support for UTF-8 does not include four-byte
sequences. (An older standard for UTF-8 encoding, RFC 2279, describes
UTF-8 sequences that take from one to six bytes. RFC 3629 renders RFC
2279 obsolete; for this reason, sequences with five and six bytes are
no longer used.)

The idea of UTF-8 is that various Unicode characters are encoded using
byte sequences of different lengths:

   * Basic Latin letters, digits, and punctuation signs use one byte.

   * Most European and Middle East script letters fit into a two-byte
     sequence: extended Latin letters (with tilde, macron, acute, grave
     and other accents), Cyrillic, Greek, Armenian, Hebrew, Arabic,
     Syriac, and others.

   * Korean, Chinese, and Japanese ideographs use three-byte sequences.

*Tip*: To save space with UTF-8, use *Note `VARCHAR': char. instead of
*Note `CHAR': char. Otherwise, MySQL must reserve three bytes for each
character in a `CHAR CHARACTER SET utf8' column because that is the
maximum possible length. For example, MySQL must reserve 30 bytes for a
`CHAR(10) CHARACTER SET utf8' column.


File: manual.info,  Node: charset-metadata,  Next: charset-conversion,  Prev: charset-unicode,  Up: charset

10.1.11 UTF-8 for Metadata
--------------------------

_Metadata_ is `the data about the data.' Anything that _describes_ the
database--as opposed to being the _contents_ of the database--is
metadata.  Thus column names, database names, user names, version names,
and most of the string results from *Note `SHOW': show. are metadata.
This is also true of the contents of tables in `INFORMATION_SCHEMA'
because those tables by definition contain information about database
objects.

Representation of metadata must satisfy these requirements:

   * All metadata must be in the same character set. Otherwise, neither
     the *Note `SHOW': show. statements nor *Note `SELECT': select.
     statements for tables in `INFORMATION_SCHEMA' would work properly
     because different rows in the same column of the results of these
     operations would be in different character sets.

   * Metadata must include all characters in all languages.  Otherwise,
     users would not be able to name columns and tables using their own
     languages.

To satisfy both requirements, MySQL stores metadata in a Unicode
character set, namely UTF-8. This does not cause any disruption if you
never use accented or non-Latin characters. But if you do, you should
be aware that metadata is in UTF-8.

The metadata requirements mean that the return values of the `USER()',
`CURRENT_USER()', `SESSION_USER()', `SYSTEM_USER()', `DATABASE()', and
`VERSION()' functions have the UTF-8 character set by default.

The server sets the `character_set_system' system variable to the name
of the metadata character set:

     mysql> SHOW VARIABLES LIKE 'character_set_system';
     +----------------------+-------+
     | Variable_name        | Value |
     +----------------------+-------+
     | character_set_system | utf8  |
     +----------------------+-------+

Storage of metadata using Unicode does _not_ mean that the server
returns headers of columns and the results of *Note `DESCRIBE':
describe. functions in the `character_set_system' character set by
default. When you use `SELECT column1 FROM t', the name `column1'
itself is returned from the server to the client in the character set
determined by the value of the `character_set_results' system variable,
which has a default value of `latin1'. If you want the server to pass
metadata results back in a different character set, use the `SET NAMES'
statement to force the server to perform character set conversion. `SET
NAMES' sets the `character_set_results' and other related system
variables. (See *Note charset-connection::.) Alternatively, a client
program can perform the conversion after receiving the result from the
server. It is more efficient for the client perform the conversion, but
this option is not always available for all clients.

If `character_set_results' is set to `NULL', no conversion is performed
and the server returns metadata using its original character set (the
set indicated by `character_set_system').

Error messages returned from the server to the client are converted to
the client character set automatically, as with metadata.

If you are using (for example) the `USER()' function for comparison or
assignment within a single statement, don't worry. MySQL performs some
automatic conversion for you.

     SELECT * FROM t1 WHERE USER() = latin1_column;

This works because the contents of `latin1_column' are automatically
converted to UTF-8 before the comparison.

     INSERT INTO t1 (latin1_column) SELECT USER();

This works because the contents of `USER()' are automatically converted
to `latin1' before the assignment.

Although automatic conversion is not in the SQL standard, the SQL
standard document does say that every character set is (in terms of
supported characters) a `subset' of Unicode. Because it is a well-known
principle that `what applies to a superset can apply to a subset,' we
believe that a collation for Unicode can apply for comparisons with
non-Unicode strings. For more information about coercion of strings,
see *Note charset-collation-expressions::.


File: manual.info,  Node: charset-conversion,  Next: charset-charsets,  Prev: charset-metadata,  Up: charset

10.1.12 Column Character Set Conversion
---------------------------------------

To convert a binary or nonbinary string column to use a particular
character set, use *Note `ALTER TABLE': alter-table. For successful
conversion to occur, one of the following conditions must apply:

   * If the column has a binary data type (*Note `BINARY':
     binary-varbinary, *Note `VARBINARY': binary-varbinary, *Note
     `BLOB': blob.), all the values that it contains must be encoded
     using a single character set (the character set you're converting
     the column to). If you use a binary column to store information in
     multiple character sets, MySQL has no way to know which values use
     which character set and cannot convert the data properly.

   * If the column has a nonbinary data type (*Note `CHAR': char, *Note
     `VARCHAR': char, *Note `TEXT': blob.), its contents should be
     encoded in the column character set, not some other character set.
     If the contents are encoded in a different character set, you can
     convert the column to use a binary data type first, and then to a
     nonbinary column with the desired character set.

Suppose that a table `t' has a binary column named `col1' defined as
`VARBINARY(50)'. Assuming that the information in the column is encoded
using a single character set, you can convert it to a nonbinary column
that has that character set.  For example, if `col1' contains binary
data representing characters in the `greek' character set, you can
convert it as follows:

     ALTER TABLE t MODIFY col1 VARCHAR(50) CHARACTER SET greek;

If your original column has a type of `BINARY(50)', you could convert
it to `CHAR(50)', but the resulting values will be padded with `0x00'
bytes at the end, which may be undesirable. To remove these bytes, use
the `TRIM()' function:

     UPDATE t SET col1 = TRIM(TRAILING 0x00 FROM col1);

Suppose that table `t' has a nonbinary column named `col1' defined as
`CHAR(50) CHARACTER SET latin1' but you want to convert it to use
`utf8' so that you can store values from many languages. The following
statement accomplishes this:

     ALTER TABLE t MODIFY col1 CHAR(50) CHARACTER SET utf8;

Conversion may be lossy if the column contains characters that are not
in both character sets.

A special case occurs if you have old tables from before MySQL 4.1
where a nonbinary column contains values that actually are encoded in a
character set different from the server's default character set. For
example, an application might have stored `sjis' values in a column,
even though MySQL's default character set was `latin1'. It is possible
to convert the column to use the proper character set but an additional
step is required. Suppose that the server's default character set was
`latin1' and `col1' is defined as `CHAR(50)' but its contents are
`sjis' values. The first step is to convert the column to a binary data
type, which removes the existing character set information without
performing any character conversion:

     ALTER TABLE t MODIFY col1 BLOB;

The next step is to convert the column to a nonbinary data type with
the proper character set:

     ALTER TABLE t MODIFY col1 CHAR(50) CHARACTER SET sjis;

This procedure requires that the table not have been modified already
with statements such as *Note `INSERT': insert. or *Note `UPDATE':
update. after an upgrade to MySQL 4.1 or later. In that case, MySQL
would store new values in the column using `latin1', and the column will
contain a mix of `sjis' and `latin1' values and cannot be converted
properly.

If you specified attributes when creating a column initially, you
should also specify them when altering the table with *Note `ALTER
TABLE': alter-table. For example, if you specified `NOT NULL' and an
explicit `DEFAULT' value, you should also provide them in the *Note
`ALTER TABLE': alter-table. statement.  Otherwise, the resulting column
definition will not include those attributes.


File: manual.info,  Node: charset-charsets,  Prev: charset-conversion,  Up: charset

10.1.13 Character Sets and Collations That MySQL Supports
---------------------------------------------------------

* Menu:

* charset-unicode-sets::         Unicode Character Sets
* charset-we-sets::              West European Character Sets
* charset-ce-sets::              Central European Character Sets
* charset-se-me-sets::           South European and Middle East Character Sets
* charset-baltic-sets::          Baltic Character Sets
* charset-cyrillic-sets::        Cyrillic Character Sets
* charset-asian-sets::           Asian Character Sets

MySQL supports 70+ collations for 30+ character sets. This section
indicates which character sets MySQL supports. There is one subsection
for each group of related character sets. For each character set, the
permissible collations are listed.

You can always list the available character sets and their default
collations with the *Note `SHOW CHARACTER SET': show-character-set.
statement:

     mysql> SHOW CHARACTER SET;
     +----------+-----------------------------+---------------------+
     | Charset  | Description                 | Default collation   |
     +----------+-----------------------------+---------------------+
     | big5     | Big5 Traditional Chinese    | big5_chinese_ci     |
     | dec8     | DEC West European           | dec8_swedish_ci     |
     | cp850    | DOS West European           | cp850_general_ci    |
     | hp8      | HP West European            | hp8_english_ci      |
     | koi8r    | KOI8-R Relcom Russian       | koi8r_general_ci    |
     | latin1   | cp1252 West European        | latin1_swedish_ci   |
     | latin2   | ISO 8859-2 Central European | latin2_general_ci   |
     | swe7     | 7bit Swedish                | swe7_swedish_ci     |
     | ascii    | US ASCII                    | ascii_general_ci    |
     | ujis     | EUC-JP Japanese             | ujis_japanese_ci    |
     | sjis     | Shift-JIS Japanese          | sjis_japanese_ci    |
     | hebrew   | ISO 8859-8 Hebrew           | hebrew_general_ci   |
     | tis620   | TIS620 Thai                 | tis620_thai_ci      |
     | euckr    | EUC-KR Korean               | euckr_korean_ci     |
     | koi8u    | KOI8-U Ukrainian            | koi8u_general_ci    |
     | gb2312   | GB2312 Simplified Chinese   | gb2312_chinese_ci   |
     | greek    | ISO 8859-7 Greek            | greek_general_ci    |
     | cp1250   | Windows Central European    | cp1250_general_ci   |
     | gbk      | GBK Simplified Chinese      | gbk_chinese_ci      |
     | latin5   | ISO 8859-9 Turkish          | latin5_turkish_ci   |
     | armscii8 | ARMSCII-8 Armenian          | armscii8_general_ci |
     | utf8     | UTF-8 Unicode               | utf8_general_ci     |
     | ucs2     | UCS-2 Unicode               | ucs2_general_ci     |
     | cp866    | DOS Russian                 | cp866_general_ci    |
     | keybcs2  | DOS Kamenicky Czech-Slovak  | keybcs2_general_ci  |
     | macce    | Mac Central European        | macce_general_ci    |
     | macroman | Mac West European           | macroman_general_ci |
     | cp852    | DOS Central European        | cp852_general_ci    |
     | latin7   | ISO 8859-13 Baltic          | latin7_general_ci   |
     | cp1251   | Windows Cyrillic            | cp1251_general_ci   |
     | cp1256   | Windows Arabic              | cp1256_general_ci   |
     | cp1257   | Windows Baltic              | cp1257_general_ci   |
     | binary   | Binary pseudo charset       | binary              |
     | geostd8  | GEOSTD8 Georgian            | geostd8_general_ci  |
     | cp932    | SJIS for Windows Japanese   | cp932_japanese_ci   |
     | eucjpms  | UJIS for Windows Japanese   | eucjpms_japanese_ci |
     +----------+-----------------------------+---------------------+

In cases where a character set has multiple collations, it might not be
clear which collation is most suitable for a given application. To
avoid choosing the wrong collation, it can be helpful to perform some
comparisons with representative data values to make sure that a given
collation sorts values the way you expect.

Collation-Charts.Org (http://www.collation-charts.org/) is a useful
site for information that shows how one collation compares to another.


File: manual.info,  Node: charset-unicode-sets,  Next: charset-we-sets,  Prev: charset-charsets,  Up: charset-charsets

10.1.13.1 Unicode Character Sets
................................

MySQL 5.0 has two Unicode character sets:

   * `ucs2', the UCS-2 encoding of the Unicode character set using 16
     bits per character

   * `utf8', a UTF-8 encoding of the Unicode character set using one to
     three bytes per character

You can store text in about 650 languages using these character sets.
This section lists the collations available for each Unicode character
set and describes their differentiating properties. For general
information about the character sets, see *Note charset-unicode::.

A similar set of collations is available for each Unicode character
set. These are shown in the following list, where XXX represents the
character set name. For example, `XXX_danish_ci' represents the Danish
collations, the specific names of which are `ucs2_danish_ci' and
`utf8_danish_ci'.

   * `XXX_bin'

   * `XXX_czech_ci'

   * `XXX_danish_ci'

   * `XXX_esperanto_ci'

   * `XXX_estonian_ci'

   * `XXX_general_ci' (default)

   * `XXX_hungarian_ci'

   * `XXX_icelandic_ci'

   * `XXX_latvian_ci'

   * `XXX_lithuanian_ci'

   * `XXX_persian_ci'

   * `XXX_polish_ci'

   * `XXX_roman_ci'

   * `XXX_romanian_ci'

   * `XXX_slovak_ci'

   * `XXX_slovenian_ci'

   * `XXX_spanish_ci'

   * `XXX_spanish2_ci'

   * `XXX_swedish_ci'

   * `XXX_turkish_ci'

   * `XXX_unicode_ci'

The `XXX_esperanto_ci' collations were added in MySQL 5.0.13. The
`XXX_hungarian_ci' collations were added in MySQL 5.0.19.

MySQL implements the `XXX_unicode_ci' collations according to the
Unicode Collation Algorithm (UCA) described at
`http://www.unicode.org/reports/tr10/'. The collation uses the
version-4.0.0 UCA weight keys:
`http://www.unicode.org/Public/UCA/4.0.0/allkeys-4.0.0.txt'.
Currently, the `XXX_unicode_ci' collations have only partial support
for the Unicode Collation Algorithm. Some characters are not supported
yet. Also, combining marks are not fully supported. This affects
primarily Vietnamese, Yoruba, and some smaller languages such as Navajo.

MySQL implements language-specific Unicode collations only if the
ordering with `XXX_unicode_ci' does not work well for a language.
Language-specific collations are UCA-based. They are derived from
`XXX_unicode_ci' with additional language tailoring rules.

For any Unicode character set, operations performed using the
`XXX_general_ci' collation are faster than those for the
`XXX_unicode_ci' collation. For example, comparisons for the
`utf8_general_ci' collation are faster, but slightly less correct, than
comparisons for `utf8_unicode_ci'. The reason for this is that
`utf8_unicode_ci' supports mappings such as expansions; that is, when
one character compares as equal to combinations of other characters.
For example, in German and some other languages ``ss'' is equal to
``ss''.  `utf8_unicode_ci' also supports contractions and ignorable
characters. `utf8_general_ci' is a legacy collation that does not
support expansions, contractions, or ignorable characters. It can make
only one-to-one comparisons between characters.

To further illustrate, the following equalities hold in both
`utf8_general_ci' and `utf8_unicode_ci' (for the effect this has in
comparisons or when doing searches, see *Note
charset-collation-effect::):

     A" = A
     O" = O
     U" = U

A difference between the collations is that this is true for
`utf8_general_ci':

     ss = s

Whereas this is true for `utf8_unicode_ci', which supports the German
DIN-1 ordering (also known as dictionary order):

     ss = ss

MySQL implements language-specific collations for the `utf8' character
set only if the ordering with `utf8_unicode_ci' does not work well for
a language. For example, `utf8_unicode_ci' works fine for German
dictionary order and French, so there is no need to create special
`utf8' collations.

`utf8_general_ci' also is satisfactory for both German and French,
except that ``ss'' is equal to ``s'', and not to ``ss''. If this is
acceptable for your application, you should use `utf8_general_ci'
because it is faster.  Otherwise, use `utf8_unicode_ci' because it is
more accurate.

`XXX_swedish_ci' includes Swedish rules. For example, in Swedish, the
following relationship holds, which is not something expected by a
German or French speaker:

     U" = Y < O"

The `XXX_spanish_ci' and `XXX_spanish2_ci' collations correspond to
modern Spanish and traditional Spanish, respectively. In both
collations, ``ñ'' (n-tilde) is a separate letter between ``n'' and
``o''. In addition, for traditional Spanish, ``ch'' is a separate
letter between ``c'' and ``d'', and ``ll'' is a separate letter between
``l'' and ``m''

In the `XXX_roman_ci' collations, `I' and `J' compare as equal, and `U'
and `V' compare as equal.

For additional information about Unicode collations in MySQL, see
Collation-Charts.Org (utf8
(http://www.collation-charts.org/mysql60/by-charset.html#utf8)).


File: manual.info,  Node: charset-we-sets,  Next: charset-ce-sets,  Prev: charset-unicode-sets,  Up: charset-charsets

10.1.13.2 West European Character Sets
......................................

Western European character sets cover most West European languages,
such as French, Spanish, Catalan, Basque, Portuguese, Italian,
Albanian, Dutch, German, Danish, Swedish, Norwegian, Finnish, Faroese,
Icelandic, Irish, Scottish, and English.

   * `ascii' (US ASCII) collations:

        * `ascii_bin'

        * `ascii_general_ci' (default)

   * `cp850' (DOS West European) collations:

        * `cp850_bin'

        * `cp850_general_ci' (default)

   * `dec8' (DEC Western European) collations:

        * `dec8_bin'

        * `dec8_swedish_ci' (default)

   * `hp8' (HP Western European) collations:

        * `hp8_bin'

        * `hp8_english_ci' (default)

   * `latin1' (cp1252 West European) collations:

        * `latin1_bin'

        * `latin1_danish_ci'

        * `latin1_general_ci'

        * `latin1_general_cs'

        * `latin1_german1_ci'

        * `latin1_german2_ci'

        * `latin1_spanish_ci'

        * `latin1_swedish_ci' (default)

     `latin1' is the default character set.  MySQL's `latin1' is the
     same as the Windows `cp1252' character set. This means it is the
     same as the official `ISO 8859-1' or IANA (Internet Assigned
     Numbers Authority) `latin1', except that IANA `latin1' treats the
     code points between `0x80' and `0x9f' as `undefined,' whereas
     `cp1252', and therefore MySQL's `latin1', assign characters for
     those positions. For example, `0x80' is the Euro sign. For the
     `undefined' entries in `cp1252', MySQL translates `0x81' to Unicode
     `0x0081', `0x8d' to `0x008d', `0x8f' to `0x008f', `0x90' to
     `0x0090', and `0x9d' to `0x009d'.

     The `latin1_swedish_ci' collation is the default that probably is
     used by the majority of MySQL customers. Although it is frequently
     said that it is based on the Swedish/Finnish collation rules,
     there are Swedes and Finns who disagree with this statement.

     The `latin1_german1_ci' and `latin1_german2_ci' collations are
     based on the DIN-1 and DIN-2 standards, where DIN stands for
     _Deutsches Institut fu"r Normung_ (the German equivalent of ANSI).
     DIN-1 is called the `dictionary collation' and DIN-2 is called the
     `phone book collation.' For an example of the effect this has in
     comparisons or when doing searches, see *Note
     charset-collation-effect::.

        * `latin1_german1_ci' (dictionary) rules:

               A" = A
               O" = O
               U" = U
               ss = s

        * `latin1_german2_ci' (phone-book) rules:

               A" = AE
               O" = OE
               U" = UE
               ss = ss

     In the `latin1_spanish_ci' collation, ``ñ'' (n-tilde) is a
     separate letter between ``n'' and ``o''.

   * `macroman' (Mac West European) collations:

        * `macroman_bin'

        * `macroman_general_ci' (default)

   * `swe7' (7bit Swedish) collations:

        * `swe7_bin'

        * `swe7_swedish_ci' (default)

For additional information about Western European collations in MySQL,
see Collation-Charts.Org (ascii
(http://www.collation-charts.org/mysql60/by-charset.html#ascii), cp850
(http://www.collation-charts.org/mysql60/by-charset.html#cp850), dec8
(http://www.collation-charts.org/mysql60/by-charset.html#dec8), hp8
(http://www.collation-charts.org/mysql60/by-charset.html#hp8), latin1
(http://www.collation-charts.org/mysql60/by-charset.html#latin1),
macroman
(http://www.collation-charts.org/mysql60/by-charset.html#macroman),
swe7 (http://www.collation-charts.org/mysql60/by-charset.html#swe7)).


File: manual.info,  Node: charset-ce-sets,  Next: charset-se-me-sets,  Prev: charset-we-sets,  Up: charset-charsets

10.1.13.3 Central European Character Sets
.........................................

MySQL provides some support for character sets used in the Czech
Republic, Slovakia, Hungary, Romania, Slovenia, Croatia, Poland, and
Serbia (Latin).

   * `cp1250' (Windows Central European) collations:

        * `cp1250_bin'

        * `cp1250_croatian_ci'

        * `cp1250_czech_cs'

        * `cp1250_general_ci' (default)

   * `cp852' (DOS Central European) collations:

        * `cp852_bin'

        * `cp852_general_ci' (default)

   * `keybcs2' (DOS Kamenicky Czech-Slovak) collations:

        * `keybcs2_bin'

        * `keybcs2_general_ci' (default)

   * `latin2' (ISO 8859-2 Central European) collations:

        * `latin2_bin'

        * `latin2_croatian_ci'

        * `latin2_czech_cs'

        * `latin2_general_ci' (default)

        * `latin2_hungarian_ci'

   * `macce' (Mac Central European) collations:

        * `macce_bin'

        * `macce_general_ci' (default)

For additional information about Central European collations in MySQL,
see Collation-Charts.Org (cp1250
(http://www.collation-charts.org/mysql60/by-charset.html#cp1250), cp852
(http://www.collation-charts.org/mysql60/by-charset.html#cp852),
keybcs2
(http://www.collation-charts.org/mysql60/by-charset.html#keybcs2),
latin2 (http://www.collation-charts.org/mysql60/by-charset.html#latin2),
macce (http://www.collation-charts.org/mysql60/by-charset.html#macce)).


File: manual.info,  Node: charset-se-me-sets,  Next: charset-baltic-sets,  Prev: charset-ce-sets,  Up: charset-charsets

10.1.13.4 South European and Middle East Character Sets
.......................................................

South European and Middle Eastern character sets supported by MySQL
include Armenian, Arabic, Georgian, Greek, Hebrew, and Turkish.

   * `armscii8' (ARMSCII-8 Armenian) collations:

        * `armscii8_bin'

        * `armscii8_general_ci' (default)

   * `cp1256' (Windows Arabic) collations:

        * `cp1256_bin'

        * `cp1256_general_ci' (default)

   * `geostd8' (GEOSTD8 Georgian) collations:

        * `geostd8_bin'

        * `geostd8_general_ci' (default)

   * `greek' (ISO 8859-7 Greek) collations:

        * `greek_bin'

        * `greek_general_ci' (default)

   * `hebrew' (ISO 8859-8 Hebrew) collations:

        * `hebrew_bin'

        * `hebrew_general_ci' (default)

   * `latin5' (ISO 8859-9 Turkish) collations:

        * `latin5_bin'

        * `latin5_turkish_ci' (default)

For additional information about South European and Middle Eastern
collations in MySQL, see Collation-Charts.Org (armscii8
(http://www.collation-charts.org/mysql60/by-charset.html#armscii8),
cp1256 (http://www.collation-charts.org/mysql60/by-charset.html#cp1256),
geostd8
(http://www.collation-charts.org/mysql60/by-charset.html#geostd8),
greek (http://www.collation-charts.org/mysql60/by-charset.html#greek),
hebrew (http://www.collation-charts.org/mysql60/by-charset.html#hebrew),
latin5
(http://www.collation-charts.org/mysql60/by-charset.html#latin5)).


File: manual.info,  Node: charset-baltic-sets,  Next: charset-cyrillic-sets,  Prev: charset-se-me-sets,  Up: charset-charsets

10.1.13.5 Baltic Character Sets
...............................

The Baltic character sets cover Estonian, Latvian, and Lithuanian
languages.

   * `cp1257' (Windows Baltic) collations:

        * `cp1257_bin'

        * `cp1257_general_ci' (default)

        * `cp1257_lithuanian_ci'

   * `latin7' (ISO 8859-13 Baltic) collations:

        * `latin7_bin'

        * `latin7_estonian_cs'

        * `latin7_general_ci' (default)

        * `latin7_general_cs'

For additional information about Baltic collations in MySQL, see
Collation-Charts.Org (cp1257
(http://www.collation-charts.org/mysql60/by-charset.html#cp1257),
latin7
(http://www.collation-charts.org/mysql60/by-charset.html#latin7)).


File: manual.info,  Node: charset-cyrillic-sets,  Next: charset-asian-sets,  Prev: charset-baltic-sets,  Up: charset-charsets

10.1.13.6 Cyrillic Character Sets
.................................

The Cyrillic character sets and collations are for use with Belarusian,
Bulgarian, Russian, Ukrainian, and Serbian (Cyrillic) languages.

   * `cp1251' (Windows Cyrillic) collations:

        * `cp1251_bin'

        * `cp1251_bulgarian_ci'

        * `cp1251_general_ci' (default)

        * `cp1251_general_cs'

        * `cp1251_ukrainian_ci'

   * `cp866' (DOS Russian) collations:

        * `cp866_bin'

        * `cp866_general_ci' (default)

   * `koi8r' (KOI8-R Relcom Russian) collations:

        * `koi8r_bin'

        * `koi8r_general_ci' (default)

   * `koi8u' (KOI8-U Ukrainian) collations:

        * `koi8u_bin'

        * `koi8u_general_ci' (default)

For additional information about Cyrillic collations in MySQL, see
Collation-Charts.Org (cp1251
(http://www.collation-charts.org/mysql60/by-charset.html#cp1251), cp866
(http://www.collation-charts.org/mysql60/by-charset.html#cp866), koi8r
(http://www.collation-charts.org/mysql60/by-charset.html#koi8r), koi8u
(http://www.collation-charts.org/mysql60/by-charset.html#koi8u)).  ).


File: manual.info,  Node: charset-asian-sets,  Prev: charset-cyrillic-sets,  Up: charset-charsets

10.1.13.7 Asian Character Sets
..............................

* Menu:

* charset-cp932::                The `cp932' Character Set

The Asian character sets that we support include Chinese, Japanese,
Korean, and Thai. These can be complicated. For example, the Chinese
sets must allow for thousands of different characters. See *Note
charset-cp932::, for additional information about the `cp932' and
`sjis' character sets.

For answers to some common questions and problems relating support for
Asian character sets in MySQL, see *Note faqs-cjk::.

   * `big5' (Big5 Traditional Chinese) collations:

        * `big5_bin'

        * `big5_chinese_ci' (default)

   * `cp932' (SJIS for Windows Japanese) collations:

        * `cp932_bin'

        * `cp932_japanese_ci' (default)

   * `eucjpms' (UJIS for Windows Japanese) collations:

        * `eucjpms_bin'

        * `eucjpms_japanese_ci' (default)

   * `euckr' (EUC-KR Korean) collations:

        * `euckr_bin'

        * `euckr_korean_ci' (default)

   * `gb2312' (GB2312 Simplified Chinese) collations:

        * `gb2312_bin'

        * `gb2312_chinese_ci' (default)

   * `gbk' (GBK Simplified Chinese) collations:

        * `gbk_bin'

        * `gbk_chinese_ci' (default)

   * `sjis' (Shift-JIS Japanese) collations:

        * `sjis_bin'

        * `sjis_japanese_ci' (default)

   * `tis620' (TIS620 Thai) collations:

        * `tis620_bin'

        * `tis620_thai_ci' (default)

   * `ujis' (EUC-JP Japanese) collations:

        * `ujis_bin'

        * `ujis_japanese_ci' (default)

The `big5_chinese_ci' collation sorts on number of strokes.

For additional information about Asian collations in MySQL, see
Collation-Charts.Org (big5
(http://www.collation-charts.org/mysql60/by-charset.html#big5), cp932
(http://www.collation-charts.org/mysql60/by-charset.html#cp932),
eucjpms
(http://www.collation-charts.org/mysql60/by-charset.html#eucjpms),
euckr (http://www.collation-charts.org/mysql60/by-charset.html#euckr),
gb2312 (http://www.collation-charts.org/mysql60/by-charset.html#gb2312),
gbk (http://www.collation-charts.org/mysql60/by-charset.html#gbk), sjis
(http://www.collation-charts.org/mysql60/by-charset.html#sjis), tis620
(http://www.collation-charts.org/mysql60/by-charset.html#tis620), ujis
(http://www.collation-charts.org/mysql60/by-charset.html#ujis)).


File: manual.info,  Node: charset-cp932,  Prev: charset-asian-sets,  Up: charset-asian-sets

10.1.13.8 The `cp932' Character Set
...................................

*Why is `cp932' needed?*

In MySQL, the `sjis' character set corresponds to the `Shift_JIS'
character set defined by IANA, which supports JIS X0201 and JIS X0208
characters. (See `http://www.iana.org/assignments/character-sets'.)

However, the meaning of `SHIFT JIS' as a descriptive term has become
very vague and it often includes the extensions to `Shift_JIS' that are
defined by various vendors.

For example, `SHIFT JIS' used in Japanese Windows environments is a
Microsoft extension of `Shift_JIS' and its exact name is `Microsoft
Windows Codepage : 932' or `cp932'. In addition to the characters
supported by `Shift_JIS', `cp932' supports extension characters such as
NEC special characters, NEC selected--IBM extended characters, and IBM
selected characters.

Many Japanese users have experienced problems using these extension
characters. These problems stem from the following factors:

   * MySQL automatically converts character sets.

   * Character sets are converted using Unicode (`ucs2').

   * The `sjis' character set does not support the conversion of these
     extension characters.

   * There are several conversion rules from so-called `SHIFT JIS' to
     Unicode, and some characters are converted to Unicode differently
     depending on the conversion rule. MySQL supports only one of these
     rules (described later).

The MySQL `cp932' character set is designed to solve these problems. It
is available as of MySQL 5.0.3.

Because MySQL supports character set conversion, it is important to
separate IANA `Shift_JIS' and `cp932' into two different character sets
because they provide different conversion rules.

*How does `cp932' differ from `sjis'?*

The `cp932' character set differs from `sjis' in the following ways:

   * `cp932' supports NEC special characters, NEC selected--IBM
     extended characters, and IBM selected characters.

   * Some `cp932' characters have two different code points, both of
     which convert to the same Unicode code point. When converting from
     Unicode back to `cp932', one of the code points must be selected.
     For this `round trip conversion,' the rule recommended by
     Microsoft is used. (See
     `http://support.microsoft.com/kb/170559/EN-US/'.)

     The conversion rule works like this:

        * If the character is in both JIS X 0208 and NEC special
          characters, use the code point of JIS X 0208.

        * If the character is in both NEC special characters and IBM
          selected characters, use the code point of NEC special
          characters.

        * If the character is in both IBM selected characters and NEC
          selected--IBM extended characters, use the code point of IBM
          extended characters.

     The table shown at
     `http://www.microsoft.com/globaldev/reference/dbcs/932.htm'
     provides information about the Unicode values of `cp932'
     characters. For `cp932' table entries with characters under which
     a four-digit number appears, the number represents the
     corresponding Unicode (`ucs2') encoding. For table entries with an
     underlined two-digit value appears, there is a range of `cp932'
     character values that begin with those two digits. Clicking such a
     table entry takes you to a page that displays the Unicode value for
     each of the `cp932' characters that begin with those digits.

     The following links are of special interest. They correspond to
     the encodings for the following sets of characters:

        * NEC special characters:

               `http://www.microsoft.com/globaldev/reference/dbcs/932/932_87.htm'

        * NEC selected--IBM extended characters:

               `http://www.microsoft.com/globaldev/reference/dbcs/932/932_ED.htm'
               `http://www.microsoft.com/globaldev/reference/dbcs/932/932_EE.htm'

        * IBM selected characters:

               `http://www.microsoft.com/globaldev/reference/dbcs/932/932_FA.htm'
               `http://www.microsoft.com/globaldev/reference/dbcs/932/932_FB.htm'
               `http://www.microsoft.com/globaldev/reference/dbcs/932/932_FC.htm'

   * Starting from version 5.0.3, `cp932' supports conversion of
     user-defined characters in combination with `eucjpms', and solves
     the problems with `sjis'/`ujis' conversion. For details, please
     refer to `http://www.opengroup.or.jp/jvc/cde/sjis-euc-e.html'.

For some characters, conversion to and from `ucs2' is different for
`sjis' and `cp932'. The following tables illustrate these differences.

Conversion to `ucs2':

`sjis'/`cp932' Value     `sjis' -> `ucs2'         `cp932' -> `ucs2'
                         Conversion               Conversion
5C                       005C                     005C
7E                       007E                     007E
815C                     2015                     2015
815F                     005C                     FF3C
8160                     301C                     FF5E
8161                     2016                     2225
817C                     2212                     FF0D
8191                     00A2                     FFE0
8192                     00A3                     FFE1
81CA                     00AC                     FFE2

Conversion from `ucs2':

`ucs2' value             `ucs2' -> `sjis'         `ucs2' -> `cp932'
                         Conversion               Conversion
005C                     815F                     5C
007E                     7E                       7E
00A2                     8191                     3F
00A3                     8192                     3F
00AC                     81CA                     3F
2015                     815C                     815C
2016                     8161                     3F
2212                     817C                     3F
2225                     3F                       8161
301C                     8160                     3F
FF0D                     3F                       817C
FF3C                     3F                       815F
FF5E                     3F                       8160
FFE0                     3F                       8191
FFE1                     3F                       8192
FFE2                     3F                       81CA

Users of any Japanese character sets should be aware that using
`--character-set-client-handshake' (or
`--skip-character-set-client-handshake') has an important effect. See
*Note server-options::.


File: manual.info,  Node: error-message-language,  Next: adding-character-set,  Prev: charset,  Up: globalization

10.2 Setting the Error Message Language
=======================================

By default, *Note `mysqld': mysqld. produces error messages in English,
but they can also be displayed in any of several other languages:
Czech, Danish, Dutch, Estonian, French, German, Greek, Hungarian,
Italian, Japanese, Korean, Norwegian, Norwegian-ny, Polish, Portuguese,
Romanian, Russian, Slovak, Spanish, or Swedish.

You can select which language the server uses for error messages using
the instructions in this section.

To start *Note `mysqld': mysqld. with a particular language for error
messages, use the `--language' or `-L' option. The option value can be
a language name or the full path to the error message file. For example:

     shell> mysqld --language=swedish

Or:

     shell> mysqld --language=/usr/local/share/swedish

The language name should be specified in lowercase.

By default, the language files are located in the `share/mysql/LANGUAGE'
directory under the MySQL base directory.

For information about changing the character set for error messages
(rather than the language), see *Note charset-errors::.

You can change the content of the error messages produced by the server
using the instructions in the MySQL Internals manual, available at
`http://forge.mysql.com/wiki/MySQL_Internals_Error_Messages'.  If you
do change the content of error messages, remember to repeat your
changes after each upgrade to a newer version of MySQL.


File: manual.info,  Node: adding-character-set,  Next: adding-collation,  Prev: error-message-language,  Up: globalization

10.3 Adding a Character Set
===========================

* Menu:

* character-arrays::             Character Definition Arrays
* string-collating::             String Collating Support for Complex Character Sets
* multi-byte-characters::        Multi-Byte Character Support for Complex Character Sets

This section discusses the procedure for adding a character set to
MySQL. The proper procedure depends on whether the character set is
simple or complex:

   * If the character set does not need special string collating
     routines for sorting and does not need multi-byte character
     support, it is simple.

   * If the character set needs either of those features, it is complex.

For example, `greek' and `swe7' are simple character sets, whereas
`big5' and `czech' are complex character sets.

To use the following instructions, you must have a MySQL source
distribution. In the instructions, MYSET represents the name of the
character set that you want to add.

  1. Add a `<charset>' element for MYSET to the
     `sql/share/charsets/Index.xml' file. Use the existing contents in
     the file as a guide to adding new contents. A partial listing for
     the `latin1' `<charset>' element follows:

          <charset name="latin1">
            <family>Western</family>
            <description>cp1252 West European</description>
            ...
            <collation name="latin1_swedish_ci"	id="8"	order="Finnish, Swedish">
              <flag>primary</flag>
              <flag>compiled</flag>
            </collation>
            <collation name="latin1_danish_ci"	id="15"	order="Danish"/>
            ...
            <collation name="latin1_bin"		id="47"	order="Binary">
              <flag>binary</flag>
              <flag>compiled</flag>
            </collation>
            ...
          </charset>

     The `<charset>' element must list all the collations for the
     character set. These must include at least a binary collation and
     a default (primary) collation.  The default collation is often
     named using a suffix of `general_ci' (general, case insensitive).
     It is possible for the binary collation to be the default
     collation, but usually they are different. The default collation
     should have a `primary' flag. The binary collation should have a
     `binary' flag.

     You must assign a unique ID number to each collation, chosen from
     the range 1 to 254. To find the maximum of the currently used
     collation IDs, use this query:

          SELECT MAX(ID) FROM INFORMATION_SCHEMA.COLLATIONS;

  2. This step depends on whether you are adding a simple or complex
     character set. A simple character set requires only a
     configuration file, whereas a complex character set requires C
     source file that defines collation functions, multi-byte
     functions, or both.

     For a simple character set, create a configuration file,
     `MYSET.xml', that describes the character set properties. Create
     this file in the `sql/share/charsets' directory. You can use a
     copy of `latin1.xml' as the basis for this file. The syntax for
     the file is very simple:

        * Comments are written as ordinary XML comments (`<!-- TEXT
          -->').

        * Words within `<map>' array elements are separated by
          arbitrary amounts of whitespace.

        * Each word within `<map>' array elements must be a number in
          hexadecimal format.

        * The `<map>' array element for the `<ctype>' element has 257
          words.  The other `<map>' array elements after that have 256
          words. See *Note character-arrays::.

        * For each collation listed in the `<charset>' element for the
          character set in `Index.xml', `MYSET.xml' must contain a
          `<collation>' element that defines the character ordering.

     For a complex character set, create a C source file that describes
     the character set properties and defines the support routines
     necessary to properly perform operations on the character set:

        * Create the file `ctype-MYSET.c' in the `strings' directory.
          Look at one of the existing `ctype-*.c' files (such as
          `ctype-big5.c') to see what needs to be defined. The arrays
          in your file must have names like `ctype_MYSET',
          `to_lower_MYSET', and so on. These correspond to the arrays
          for a simple character set. See *Note character-arrays::.

        * For each `<collation>' element listed in the `<charset>'
          element for the character set in `Index.xml', the
          `ctype-MYSET.c' file must provide an implementation of the
          collation.

        * If the character set requires string collating functions, see
          *Note string-collating::.

        * If the character set requires multi-byte character support,
          see *Note multi-byte-characters::.

  3. Modify the configuration information. Use the existing
     configuration information as a guide to adding information for
     MYSYS. The example here assumes that the character set has default
     and binary collations, but more lines are needed if MYSET has
     additional collations.

       1. Edit `mysys/charset-def.c', and `register' the collations for
          the new character set.

          Add these lines to the `declaration' section:

               #ifdef HAVE_CHARSET_MYSET
               extern CHARSET_INFO my_charset_MYSET_general_ci;
               extern CHARSET_INFO my_charset_MYSET_bin;
               #endif

          Add these lines to the `registration' section:

               #ifdef HAVE_CHARSET_MYSET
                 add_compiled_collation(&my_charset_MYSET_general_ci);
                 add_compiled_collation(&my_charset_MYSET_bin);
               #endif

       2. If the character set uses `ctype-MYSET.c', edit
          `strings/Makefile.am' and add `ctype-MYSET.c' to each
          definition of the `CSRCS' variable, and to the `EXTRA_DIST'
          variable.

       3. If the character set uses `ctype-MYSET.c', edit
          `libmysql/Makefile.shared' and add `ctype-MYSET.lo' to the
          `mystringsobjects' definition.

       4. Edit `config/ac-macros/character_sets.m4':

            1. Add MYSET to one of the `define(CHARSETS_AVAILABLE...)'
               lines in alphabetic order.

            2. Add MYSET to `CHARSETS_COMPLEX'. This is needed even for
               simple character sets, or `configure' will not recognize
               `--with-charset=MYSET'.

            3. Add MYSET to the first `case' control structure. Omit the
               `USE_MB' and `USE_MB_IDENT' lines for 8-bit character
               sets.

                    MYSET)
                      AC_DEFINE(HAVE_CHARSET_MYSET, 1, [Define to enable charset MYSET])
                      AC_DEFINE([USE_MB], 1, [Use multi-byte character routines])
                      AC_DEFINE(USE_MB_IDENT, 1)
                      ;;

            4. Add MYSET to the second `case' control structure:

                    MYSET)
                      default_charset_default_collation="MYSET_general_ci"
                      default_charset_collations="MYSET_general_ci MYSET_bin"
                      ;;

  4. Reconfigure, recompile, and test.


File: manual.info,  Node: character-arrays,  Next: string-collating,  Prev: adding-character-set,  Up: adding-character-set

10.3.1 Character Definition Arrays
----------------------------------

Each simple character set has a configuration file located in the
`sql/share/charsets' directory. For a character set named MYSYS, the
file is named `MYSET.xml'. It uses `<map>' array elements to list
character set properties. `<map>' elements appear within these elements:

   * `<ctype>' defines attributes for each character.

   * `<lower>' and `<upper>' list the lowercase and uppercase
     characters.

   * `<unicode>' maps 8-bit character values to Unicode values.

   * `<collation>' elements indicate character ordering for comparisons
     and sorts, one element per collation. Binary collations need no
     `<map>' element because the character codes themselves provide the
     ordering.

For a complex character set as implemented in a `ctype-MYSET.c' file in
the `strings' directory, there are corresponding arrays:
`ctype_MYSET[]', `to_lower_MYSET[]', and so forth. Not every complex
character set has all of the arrays. See also the existing `ctype-*.c'
files for examples. See the `CHARSET_INFO.txt' file in the `strings'
directory for additional information.

Most of the arrays are indexed by character value and have 256
elements. The `<ctype>' array is indexed by character value + 1 and has
257 elements. This is a legacy convention for handling `EOF'.

`<ctype>' array elements are bit values.  Each element describes the
attributes of a single character in the character set. Each attribute
is associated with a bitmask, as defined in `include/m_ctype.h':

     #define _MY_U   01      /* Upper case */
     #define _MY_L   02      /* Lower case */
     #define _MY_NMR 04      /* Numeral (digit) */
     #define _MY_SPC 010     /* Spacing character */
     #define _MY_PNT 020     /* Punctuation */
     #define _MY_CTR 040     /* Control character */
     #define _MY_B   0100    /* Blank */
     #define _MY_X   0200    /* heXadecimal digit */

The `<ctype>' value for a given character should be the union of the
applicable bitmask values that describe the character. For example,
`'A'' is an uppercase character (`_MY_U') as well as a hexadecimal
digit (`_MY_X'), so its `ctype' value should be defined like this:

     ctype['A'+1] = _MY_U | _MY_X = 01 | 0200 = 0201

The bitmask values in `m_ctype.h' are octal values, but the elements of
the `<ctype>' array in `MYSET.xml' should be written as hexadecimal
values.

The `<lower>' and `<upper>' arrays hold the lowercase and uppercase
characters corresponding to each member of the character set. For
example:

     lower['A'] should contain 'a'
     upper['a'] should contain 'A'

Each `<collation>' array indicates how characters should be ordered for
comparison and sorting purposes. MySQL sorts characters based on the
values of this information. In some cases, this is the same as the
`<upper>' array, which means that sorting is case-insensitive. For more
complicated sorting rules (for complex character sets), see the
discussion of string collating in *Note string-collating::.


File: manual.info,  Node: string-collating,  Next: multi-byte-characters,  Prev: character-arrays,  Up: adding-character-set

10.3.2 String Collating Support for Complex Character Sets
----------------------------------------------------------

For a simple character set named MYSET, sorting rules are specified in
the `MYSET.xml' configuration file using `<map>' array elements within
`<collation>' elements.  If the sorting rules for your language are too
complex to be handled with simple arrays, you must define string
collating functions in the `ctype-MYSET.c' source file in the `strings'
directory.

The existing character sets provide the best documentation and examples
to show how these functions are implemented. Look at the `ctype-*.c'
files in the `strings' directory, such as the files for the `big5',
`czech', `gbk', `sjis', and `tis160' character sets. Take a look at the
`MY_COLLATION_HANDLER' structures to see how they are used. See also the
`CHARSET_INFO.txt' file in the `strings' directory for additional
information.


File: manual.info,  Node: multi-byte-characters,  Prev: string-collating,  Up: adding-character-set

10.3.3 Multi-Byte Character Support for Complex Character Sets
--------------------------------------------------------------

If you want to add support for a new character set named MYSET that
includes multi-byte characters, you must use multi-byte character
functions in the `ctype-MYSET.c' source file in the `strings' directory.

The existing character sets provide the best documentation and examples
to show how these functions are implemented. Look at the `ctype-*.c'
files in the `strings' directory, such as the files for the `euc_kr',
`gb2312', `gbk', `sjis', and `ujis' character sets. Take a look at the
`MY_CHARSET_HANDLER' structures to see how they are used. See also the
`CHARSET_INFO.txt' file in the `strings' directory for additional
information.


File: manual.info,  Node: adding-collation,  Next: charset-configuration,  Prev: adding-character-set,  Up: globalization

10.4 Adding a Collation to a Character Set
==========================================

* Menu:

* charset-collation-implementations::  Collation Implementation Types
* adding-collation-choosing-id::  Choosing a Collation ID
* adding-collation-simple-8bit::  Adding a Simple Collation to an 8-Bit Character Set
* adding-collation-unicode-uca::  Adding a UCA Collation to a Unicode Character Set

A collation is a set of rules that defines how to compare and sort
character strings. Each collation in MySQL belongs to a single
character set. Every character set has at least one collation, and most
have two or more collations.

A collation orders characters based on weights. Each character in a
character set maps to a weight. Characters with equal weights compare
as equal, and characters with unequal weights compare according to the
relative magnitude of their weights.

MySQL supports several collation implementations, as discussed in *Note
charset-collation-implementations::. Some of these can be added to
MySQL without recompiling:

   * Simple collations for 8-bit character sets

   * UCA-based collations for Unicode character sets

   * Binary (`XXX_bin') collations

The following sections describe how to add collations of the first two
types to existing character sets. All existing character sets already
have a binary collation, so there is no need here to describe how to
add one.

Summary of the procedure for adding a new collation:

  1. Choose a collation ID

  2. Add configuration information that names the collation and
     describes the character-ordering rules

  3. Restart the server

  4. Verify that the collation is present

The instructions here cover only collations that can be added without
recompiling MySQL. To add a collation that does require recompiling (as
implemented by means of functions in a C source file), use the
instructions in *Note adding-character-set::. However, instead of adding
all the information required for a complete character set, just modify
the appropriate files for an existing character set. That is, based on
what is already present for the character set's current collations, add
data structures, functions, and configuration information for the new
collation.

*Note*:

If you modify an existing collation, that may affect the ordering of
rows for indexes on columns that use the collation.  In this case,
rebuild any such indexes to avoid problems such as incorrect query
results. For further information, see *Note
checking-table-incompatibilities::.

* Additional Resources *

   * The Unicode Collation Algorithm (UCA) specification:
     `http://www.unicode.org/reports/tr10/'

   * The Locale Data Markup Language (LDML) specification:
     `http://www.unicode.org/reports/tr35/'

   * MySQL University session `How to Add a Collation':
     `http://forge.mysql.com/wiki/How_to_Add_a_Collation'

   * MySQL Blog article `Instructions for adding a new Unicode
     collation':
     `http://blogs.mysql.com/peterg/2008/05/19/instructions-for-adding-a-new-unicode-collation/'


File: manual.info,  Node: charset-collation-implementations,  Next: adding-collation-choosing-id,  Prev: adding-collation,  Up: adding-collation

10.4.1 Collation Implementation Types
-------------------------------------

MySQL implements several types of collations:

*Simple collations for 8-bit character sets*

This kind of collation is implemented using an array of 256 weights
that defines a one-to-one mapping from character codes to weights.
`latin1_swedish_ci' is an example.  It is a case-insensitive collation,
so the uppercase and lowercase versions of a character have the same
weights and they compare as equal.

     mysql> SET NAMES 'latin1' COLLATE 'latin1_swedish_ci';
     Query OK, 0 rows affected (0.00 sec)

     mysql> SELECT 'a' = 'A';
     +-----------+
     | 'a' = 'A' |
     +-----------+
     |         1 |
     +-----------+
     1 row in set (0.00 sec)

For implementation instructions, see *Note
adding-collation-simple-8bit::.

*Complex collations for 8-bit character sets*

This kind of collation is implemented using functions in a C source
file that define how to order characters, as described in *Note
adding-character-set::.

*Collations for non-Unicode multi-byte character sets*

For this type of collation, 8-bit (single-byte) and multi-byte
characters are handled differently. For 8-bit characters, character
codes map to weights in case-insensitive fashion. (For example, the
single-byte characters `'a'' and `'A'' both have a weight of `0x41'.)
For multi-byte characters, there are two types of relationship between
character codes and weights:

   * Weights equal character codes.  `sjis_japanese_ci' is an example
     of this kind of collation. The multi-byte character `'ぢ'' has a
     character code of `0x82C0', and the weight is also `0x82C0'.

   * Character codes map one-to-one to weights, but a code is not
     necessarily equal to the weight.  `gbk_chinese_ci' is an example
     of this kind of collation. The multi-byte character `'膰'' has a
     character code of `0x81B0' but a weight of `0xC286'.

For implementation instructions, see *Note adding-character-set::.

*Collations for Unicode multi-byte character sets*

Some of these collations are based on the Unicode Collation Algorithm
(UCA), others are not.

Non-UCA collations have a one-to-one mapping from character code to
weight. In MySQL, such collations are case insensitive and accent
insensitive. `utf8_general_ci' is an example: `'a'', `'A'', `'A`'', and
`'a''' each have different character codes but all have a weight of
`0x0041' and compare as equal.

     mysql> SET NAMES 'utf8' COLLATE 'utf8_general_ci';
     Query OK, 0 rows affected (0.00 sec)

     mysql> SELECT 'a' = 'A', 'a' = 'A`', 'a' = 'a'';
     +-----------+-----------+-----------+
     | 'a' = 'A' | 'a' = 'A`' | 'a' = 'a'' |
     +-----------+-----------+-----------+
     |         1 |         1 |         1 |
     +-----------+-----------+-----------+
     1 row in set (0.06 sec)

UCA-based collations in MySQL have these properties:

   * If a character has weights, each weight uses 2 bytes (16 bits)

   * A character may have zero weights (or an empty weight). In this
     case, the character is ignorable. Example: "U+0000 NULL" does not
     have a weight and is ignorable.

   * A character may have one weight. Example: `'a'' has a weight of
     `0x0E33'.

   * A character may have many weights. This is an expansion.  Example:
     The German letter `'ss'' (SZ ligature, or SHARP S) has a weight of
     `0x0FEA0FEA'.

   * Many characters may have one weight. This is a contraction.
     Example: `'ch'' is a single letter in Czech and has a weight of
     `0x0EE2'.

A many-characters-to-many-weights mapping is also possible (this is
contraction with expansion), but is not supported by MySQL.

For implementation instructions, for a non-UCA collation, see *Note
adding-character-set::. For a UCA collation, see *Note
adding-collation-unicode-uca::.

*Miscellaneous collations*

There are also a few collations that do not fall into any of the
previous categories.


File: manual.info,  Node: adding-collation-choosing-id,  Next: adding-collation-simple-8bit,  Prev: charset-collation-implementations,  Up: adding-collation

10.4.2 Choosing a Collation ID
------------------------------

Each collation must have a unique ID. To add a collation, you must
choose an ID value that is not currently used. The value must be in the
range from 1 to 254. The collation ID that you choose will appear in
these contexts:

   * The `ID' column of the *Note `INFORMATION_SCHEMA.COLLATIONS':
     collations-table.  table

   * The `Id' column of *Note `SHOW COLLATION': show-collation. output

   * The `charsetnr' member of the `MYSQL_FIELD' C API data structure

   * The `number' member of the `MY_CHARSET_INFO' data structure
     returned by the *Note `mysql_get_character_set_info()':
     mysql-get-character-set-info.  C API function

To determine the largest currently used ID, issue the following
statement:

     mysql> SELECT MAX(ID) FROM INFORMATION_SCHEMA.COLLATIONS;
     +---------+
     | MAX(ID) |
     +---------+
     |     210 |
     +---------+

For the output just shown, you could choose an ID higher than 210 for
the new collation.

To display a list of all currently used IDs, issue this statement:

     mysql> SELECT ID FROM INFORMATION_SCHEMA.COLLATIONS ORDER BY ID;
     +-----+
     | ID  |
     +-----+
     |   1 |
     |   2 |
     | ... |
     |  52 |
     |  53 |
     |  57 |
     |  58 |
     | ... |
     |  98 |
     |  99 |
     | 128 |
     | 129 |
     | ... |
     | 210 |
     +-----+

In this case, you can either choose an unused ID from within the
current range of IDs, or choose an ID that is higher than the current
maximum ID. For example, in the output just shown, there are unused IDs
between 53 and 57, and between 99 and 128. Or you could choose an ID
higher than 210.

*Warning*:

If you upgrade MySQL, you may find that the collation ID you choose has
been assigned to a collation included in the new MySQL distribution. In
this case, you will need to choose a new value for your own collation.

In addition, before upgrading, you should save the configuration files
that you change. If you upgrade in place, the process will replace the
your modified files.


File: manual.info,  Node: adding-collation-simple-8bit,  Next: adding-collation-unicode-uca,  Prev: adding-collation-choosing-id,  Up: adding-collation

10.4.3 Adding a Simple Collation to an 8-Bit Character Set
----------------------------------------------------------

This section describes how to add a simple collation for an 8-bit
character set by writing the `<collation>' elements associated with a
`<charset>' character set description in the MySQL `Index.xml' file.
The procedure described here does not require recompiling MySQL. The
example adds a collation named `latin1_test_ci' to the `latin1'
character set.

  1. Choose a collation ID, as shown in *Note
     adding-collation-choosing-id::. The following steps use an ID of
     56.

  2. Modify the `Index.xml' and `latin1.xml' configuration files. These
     files will be located in the directory named by the
     `character_sets_dir' system variable. You can check the variable
     value as follows, although the path name might be different on
     your system:

          mysql> SHOW VARIABLES LIKE 'character_sets_dir';
          +--------------------+-----------------------------------------+
          | Variable_name      | Value                                   |
          +--------------------+-----------------------------------------+
          | character_sets_dir | /user/local/mysql/share/mysql/charsets/ |
          +--------------------+-----------------------------------------+

  3. Choose a name for the collation and list it in the `Index.xml'
     file. Find the `<charset>' element for the character set to which
     the collation is being added, and add a `<collation>' element that
     indicates the collation name and ID, to associate the name with the
     ID. For example:

          <charset name="latin1">
            ...
            <collation name="latin1_test_ci" id="56"/>
            ...
          </charset>

  4. In the `latin1.xml' configuration file, add a `<collation>'
     element that names the collation and that contains a `<map>'
     element that defines a character code-to-weight mapping table for
     character codes 0 to 255. Each value within the `<map>' element
     must be a number in hexadecimal format.

          <collation name="latin1_test_ci">
          <map>
           00 01 02 03 04 05 06 07 08 09 0A 0B 0C 0D 0E 0F
           10 11 12 13 14 15 16 17 18 19 1A 1B 1C 1D 1E 1F
           20 21 22 23 24 25 26 27 28 29 2A 2B 2C 2D 2E 2F
           30 31 32 33 34 35 36 37 38 39 3A 3B 3C 3D 3E 3F
           40 41 42 43 44 45 46 47 48 49 4A 4B 4C 4D 4E 4F
           50 51 52 53 54 55 56 57 58 59 5A 5B 5C 5D 5E 5F
           60 41 42 43 44 45 46 47 48 49 4A 4B 4C 4D 4E 4F
           50 51 52 53 54 55 56 57 58 59 5A 7B 7C 7D 7E 7F
           80 81 82 83 84 85 86 87 88 89 8A 8B 8C 8D 8E 8F
           90 91 92 93 94 95 96 97 98 99 9A 9B 9C 9D 9E 9F
           A0 A1 A2 A3 A4 A5 A6 A7 A8 A9 AA AB AC AD AE AF
           B0 B1 B2 B3 B4 B5 B6 B7 B8 B9 BA BB BC BD BE BF
           41 41 41 41 5B 5D 5B 43 45 45 45 45 49 49 49 49
           44 4E 4F 4F 4F 4F 5C D7 5C 55 55 55 59 59 DE DF
           41 41 41 41 5B 5D 5B 43 45 45 45 45 49 49 49 49
           44 4E 4F 4F 4F 4F 5C F7 5C 55 55 55 59 59 DE FF
          </map>
          </collation>

  5. Restart the server and use this statement to verify that the
     collation is present:

          mysql> SHOW COLLATION LIKE 'latin1_test_ci';
          +----------------+---------+----+---------+----------+---------+
          | Collation      | Charset | Id | Default | Compiled | Sortlen |
          +----------------+---------+----+---------+----------+---------+
          | latin1_test_ci | latin1  | 56 |         |          |       1 |
          +----------------+---------+----+---------+----------+---------+


File: manual.info,  Node: adding-collation-unicode-uca,  Prev: adding-collation-simple-8bit,  Up: adding-collation

10.4.4 Adding a UCA Collation to a Unicode Character Set
--------------------------------------------------------

* Menu:

* ldml-collation-example::       Defining a UCA Collation using LDML Syntax
* ldml-rules::                   LDML Syntax Supported in MySQL

This section describes how to add a UCA collation for a Unicode
character set by writing the `<collation>' element within a `<charset>'
character set description in the MySQL `Index.xml' file. The procedure
described here does not require recompiling MySQL. It uses a subset of
the Locale Data Markup Language (LDML) specification, which is
available at `http://www.unicode.org/reports/tr35/'. In 5.0, this
method of adding collations is supported as of MySQL 5.0.46. With this
method, you need not define the entire collation. Instead, you begin
with an existing `base' collation and describe the new collation in
terms of how it differs from the base collation. The following table
lists the base collations of the Unicode character sets for which UCA
collations can be defined.

*MySQL Character Sets Available for User-Defined UCA Collations*

Character Set          Base Collation
`utf8'                 `utf8_unicode_ci'
`ucs2'                 `ucs2_unicode_ci'

The following sections show how to add a collation that is defined
using LDML syntax, and provide a summary of LDML rules supported in
MySQL.


File: manual.info,  Node: ldml-collation-example,  Next: ldml-rules,  Prev: adding-collation-unicode-uca,  Up: adding-collation-unicode-uca

10.4.4.1 Defining a UCA Collation using LDML Syntax
...................................................

To add a UCA collation for a Unicode character set without recompiling
MySQL, use the following procedure. If you are unfamiliar with the LDML
rules used to describe the collation's sort characteristics, see *Note
ldml-rules::.

The example adds a collation named `utf8_phone_ci' to the `utf8'
character set. The collation is designed for a scenario involving a Web
application for which users post their names and phone numbers. Phone
numbers can be given in very different formats:

     +7-12345-67
     +7-12-345-67
     +7 12 345 67
     +7 (12) 345 67
     +71234567

The problem raised by dealing with these kinds of values is that the
varying permissible formats make searching for a specific phone number
very difficult. The solution is to define a new collation that reorders
punctuation characters, making them ignorable.

  1. Choose a collation ID, as shown in *Note
     adding-collation-choosing-id::. The following steps use an ID of
     252.

  2. To modify the `Index.xml' configuration file. This file will be
     located in the directory named by the `character_sets_dir' system
     variable. You can check the variable value as follows, although
     the path name might be different on your system:

          mysql> SHOW VARIABLES LIKE 'character_sets_dir';
          +--------------------+-----------------------------------------+
          | Variable_name      | Value                                   |
          +--------------------+-----------------------------------------+
          | character_sets_dir | /user/local/mysql/share/mysql/charsets/ |
          +--------------------+-----------------------------------------+

  3. Choose a name for the collation and list it in the `Index.xml'
     file. In addition, you'll need to provide the collation ordering
     rules. Find the `<charset>' element for the character set to which
     the collation is being added, and add a `<collation>' element that
     indicates the collation name and ID, to associate the name with
     the ID. Within the `<collation>' element, provide a `<rules>'
     element containing the ordering rules:

          <charset name="utf8">
            ...
            <collation name="utf8_phone_ci" id="252">
              <rules>
                <reset>\u0000</reset>
                <s>\u0020</s> <!-- space -->
                <s>\u0028</s> <!-- left parenthesis -->
                <s>\u0029</s> <!-- right parenthesis -->
                <s>\u002B</s> <!-- plus -->
                <s>\u002D</s> <!-- hyphen -->
              </rules>
            </collation>
            ...
          </charset>

  4. If you want a similar collation for other Unicode character sets,
     add other `<collation>' elements. For example, to define
     `ucs2_phone_ci', add a `<collation>' element to the `<charset
     name="ucs2">' element.  Remember that each collation must have its
     own unique ID.

  5. Restart the server and use this statement to verify that the
     collation is present:

          mysql> SHOW COLLATION LIKE 'utf8_phone_ci';
          +---------------+---------+-----+---------+----------+---------+
          | Collation     | Charset | Id  | Default | Compiled | Sortlen |
          +---------------+---------+-----+---------+----------+---------+
          | utf8_phone_ci | utf8    | 252 |         |          |       8 |
          +---------------+---------+-----+---------+----------+---------+

Now test the collation to make sure that it has the desired properties.

Create a table containing some sample phone numbers using the new
collation:

     mysql> CREATE TABLE phonebook (
         ->   name VARCHAR(64),
         ->   phone VARCHAR(64) CHARACTER SET utf8 COLLATE utf8_phone_ci
         -> );
     Query OK, 0 rows affected (0.09 sec)

     mysql> INSERT INTO phonebook VALUES ('Svoj','+7 912 800 80 02');
     Query OK, 1 row affected (0.00 sec)

     mysql> INSERT INTO phonebook VALUES ('Hf','+7 (912) 800 80 04');
     Query OK, 1 row affected (0.00 sec)

     mysql> INSERT INTO phonebook VALUES ('Bar','+7-912-800-80-01');
     Query OK, 1 row affected (0.00 sec)

     mysql> INSERT INTO phonebook VALUES ('Ramil','(7912) 800 80 03');
     Query OK, 1 row affected (0.00 sec)

     mysql> INSERT INTO phonebook VALUES ('Sanja','+380 (912) 8008005');
     Query OK, 1 row affected (0.00 sec)

Run some queries to see whether the ignored punctuation characters are
in fact ignored for sorting and comparisons:

     mysql> SELECT * FROM phonebook ORDER BY phone;
     +-------+--------------------+
     | name  | phone              |
     +-------+--------------------+
     | Sanja | +380 (912) 8008005 |
     | Bar   | +7-912-800-80-01   |
     | Svoj  | +7 912 800 80 02   |
     | Ramil | (7912) 800 80 03   |
     | Hf    | +7 (912) 800 80 04 |
     +-------+--------------------+
     5 rows in set (0.00 sec)

     mysql> SELECT * FROM phonebook WHERE phone='+7(912)800-80-01';
     +------+------------------+
     | name | phone            |
     +------+------------------+
     | Bar  | +7-912-800-80-01 |
     +------+------------------+
     1 row in set (0.00 sec)

     mysql> SELECT * FROM phonebook WHERE phone='79128008001';
     +------+------------------+
     | name | phone            |
     +------+------------------+
     | Bar  | +7-912-800-80-01 |
     +------+------------------+
     1 row in set (0.00 sec)

     mysql> SELECT * FROM phonebook WHERE phone='7 9 1 2 8 0 0 8 0 0 1';
     +------+------------------+
     | name | phone            |
     +------+------------------+
     | Bar  | +7-912-800-80-01 |
     +------+------------------+
     1 row in set (0.00 sec)


File: manual.info,  Node: ldml-rules,  Prev: ldml-collation-example,  Up: adding-collation-unicode-uca

10.4.4.2 LDML Syntax Supported in MySQL
.......................................

This section describes the LDML syntax that MySQL recognizes.  This is
a subset of the syntax described in the LDML specification available at
`http://www.unicode.org/reports/tr35/', which should be consulted for
further information. The rules described here are all supported except
that character sorting occurs only at the primary level. Rules that
specify differences at secondary or higher sort levels are recognized
(and thus can be included in collation definitions) but are treated as
equality at the primary level.

*Character Representation*

Characters named in LDML rules can be written in `\uNNNN' format, where
NNNN is the hexadecimal Unicode code point value. Within hexadecimal
values, the digits `A' through `F' are not case sensitive; `\u00E1' and
`\u00e1' are equivalent. Basic Latin letters `A-Z' and `a-z' can also be
written literally (this is a MySQL limitation; the LDML specification
permits literal non-Latin1 characters in the rules). Only characters in
the Basic Multilingual Plane can be specified. This notation does not
apply to characters outside the BMP range of `0000' to `FFFF'.

The `Index.xml' file itself should be written using ASCII encoding.

*Syntax Rules*

LDML has reset rules and shift rules to specify character ordering.
Orderings are given as a set of rules that begin with a reset rule that
establishes an anchor point, followed by shift rules that indicate how
characters sort relative to the anchor point.

   * A `<reset>' rule does not specify any ordering in and of itself.
     Instead, it `resets' the ordering for subsequent shift rules to
     cause them to be taken in relation to a given character. Either of
     the following rules resets subsequent shift rules to be taken in
     relation to the letter `'A'':

          <reset>A</reset>

          <reset>\u0041</reset>

   * The `<p>', `<s>', and `<t>' shift rules define primary, secondary,
     and tertiary differences of a character from another character:

        * Use primary differences to distinguish separate letters.

        * Use secondary differences to distinguish accent variations.

        * Use tertiary differences to distinguish lettercase variations.

     Either of these rules specifies a primary shift rule for the `'G''
     character:

          <p>G</p>

          <p>\u0047</p>


File: manual.info,  Node: charset-configuration,  Next: time-zone-support,  Prev: adding-collation,  Up: globalization

10.5 Character Set Configuration
================================

You can change the default server character set and collation with the
`--character-set-server' and `--collation-server' options when you
start the server. The collation must be a legal collation for the
default character set. (Use the *Note `SHOW COLLATION': show-collation.
statement to determine which collations are available for each
character set.) See *Note server-options::.

If you try to use a character set that is not compiled into your
binary, you might run into the following problems:

   * Your program uses an incorrect path to determine where the
     character sets are stored (which is typically the
     `share/mysql/charsets' or `share/charsets' directory under the
     MySQL installation directory). This can be fixed by using the
     `--character-sets-dir' option when you run the program in
     question. For example, to specify a directory to be used by MySQL
     client programs, list it in the `[client]' group of your option
     file. The examples given here show what the setting might look
     like for Unix or Windows, respectively:

          [client]
          character-sets-dir=/usr/local/mysql/share/mysql/charsets

          [client]
          character-sets-dir="C:/Program Files/MySQL/MySQL Server 5.0/share/charsets"

   * The character set is a complex character set that cannot be loaded
     dynamically. In this case, you must recompile the program with
     support for the character set.

     For Unicode character sets, you can define collations without
     recompiling by using LDML notation. See *Note
     adding-collation-unicode-uca::.

   * The character set is a dynamic character set, but you do not have
     a configuration file for it. In this case, you should install the
     configuration file for the character set from a new MySQL
     distribution.

   * If your character set index file does not contain the name for the
     character set, your program displays an error message. The file is
     named `Index.xml' and the message is:

          Character set 'CHARSET_NAME' is not a compiled character set and is not
          specified in the '/usr/share/mysql/charsets/Index.xml' file

     To solve this problem, you should either get a new index file or
     manually add the name of any missing character sets to the current
     file.

You can force client programs to use specific character set as follows:

     [client]
     default-character-set=CHARSET_NAME

This is normally unnecessary. However, when `character_set_system'
differs from `character_set_server' or `character_set_client', and you
input characters manually (as database object identifiers, column
values, or both), these may be displayed incorrectly in output from the
client or the output itself may be formatted incorrectly.  In such
cases, starting the mysql client with
`--default-character-set=SYSTEM_CHARACTER_SET'--that is, setting the
client character set to match the system character set--should fix the
problem.

For `MyISAM' tables, you can check the character set name and number
for a table with *Note `myisamchk -dvv TBL_NAME': myisamchk.


File: manual.info,  Node: time-zone-support,  Next: locale-support,  Prev: charset-configuration,  Up: globalization

10.6 MySQL Server Time Zone Support
===================================

* Menu:

* time-zone-upgrades::           Staying Current with Time Zone Changes
* time-zone-leap-seconds::       Time Zone Leap Second Support

The MySQL server maintains several time zone settings:

   * The system time zone. When the server starts, it attempts to
     determine the time zone of the host machine and uses it to set the
     `system_time_zone' system variable. The value does not change
     thereafter.

     You can set the system time zone for MySQL Server at startup with
     the `--timezone=TIMEZONE_NAME' option to *Note `mysqld_safe':
     mysqld-safe. You can also set it by setting the `TZ' environment
     variable before you start *Note `mysqld': mysqld. The permissible
     values for `--timezone' or `TZ' are system dependent. Consult your
     operating system documentation to see what values are acceptable.

   * The server's current time zone. The global `time_zone' system
     variable indicates the time zone the server currently is operating
     in.  The initial value for `time_zone' is `'SYSTEM'', which
     indicates that the server time zone is the same as the system time
     zone.

     The initial global server time zone value can be specified
     explicitly at startup with the `--default-time-zone=TIMEZONE'
     option on the command line, or you can use the following line in
     an option file:

          default-time-zone='TIMEZONE'

     If you have the `SUPER' privilege, you can set the global server
     time zone value at runtime with this statement:

          mysql> SET GLOBAL time_zone = TIMEZONE;

   * Per-connection time zones. Each client that connects has its own
     time zone setting, given by the session `time_zone' variable.
     Initially, the session variable takes its value from the global
     `time_zone' variable, but the client can change its own time zone
     with this statement:

          mysql> SET time_zone = TIMEZONE;

The current session time zone setting affects display and storage of
time values that are zone-sensitive. This includes the values displayed
by functions such as `NOW()' or `CURTIME()', and values stored in and
retrieved from *Note `TIMESTAMP': datetime. columns.  Values for *Note
`TIMESTAMP': datetime. columns are converted from the current time zone
to UTC for storage, and from UTC to the current time zone for retrieval.

The current time zone setting does not affect values displayed by
functions such as `UTC_TIMESTAMP()' or values in *Note `DATE': datetime,
*Note `TIME': time, or *Note `DATETIME': datetime. columns. Nor are
values in those data types stored in UTC; the time zone applies for them
only when converting from `TIMESTAMP' values. If you want
locale-specific arithmetic for *Note `DATE': datetime, *Note `TIME':
time, or *Note `DATETIME': datetime. values, convert them to UTC,
perform the arithmetic, and then convert back.

The current values of the global and client-specific time zones can be
retrieved like this:

     mysql> SELECT @@global.time_zone, @@session.time_zone;

TIMEZONE values can be given in several formats, none of which are case
sensitive:

   * The value `'SYSTEM'' indicates that the time zone should be the
     same as the system time zone.

   * The value can be given as a string indicating an offset from UTC,
     such as `'+10:00'' or `'-6:00''.

   * The value can be given as a named time zone, such as
     `'Europe/Helsinki'', `'US/Eastern'', or `'MET''.  Named time zones
     can be used only if the time zone information tables in the
     `mysql' database have been created and populated.

The MySQL installation procedure creates the time zone tables in the
`mysql' database, but does not load them. You must do so manually using
the following instructions. (If you are upgrading to MySQL 4.1.3 or
later from an earlier version, you can create the tables by upgrading
your `mysql' database. Use the instructions in *Note mysql-upgrade::.
After creating the tables, you can load them.)

*Note*:

Loading the time zone information is not necessarily a one-time
operation because the information changes occasionally. For example,
the rules for Daylight Saving Time in the United States, Mexico, and
parts of Canada changed in 2007. When such changes occur, applications
that use the old rules become out of date and you may find it necessary
to reload the time zone tables to keep the information used by your
MySQL server current. See the notes at the end of this section.

If your system has its own _zoneinfo_ database (the set of files
describing time zones), you should use the *Note `mysql_tzinfo_to_sql':
mysql-tzinfo-to-sql. program for filling the time zone tables. Examples
of such systems are Linux, FreeBSD, Solaris, and Mac OS X. One likely
location for these files is the `/usr/share/zoneinfo' directory. If
your system does not have a zoneinfo database, you can use the
downloadable package described later in this section.

The *Note `mysql_tzinfo_to_sql': mysql-tzinfo-to-sql. program is used
to load the time zone tables. On the command line, pass the zoneinfo
directory path name to *Note `mysql_tzinfo_to_sql':
mysql-tzinfo-to-sql. and send the output into the *Note `mysql': mysql.
program. For example:

     shell> mysql_tzinfo_to_sql /usr/share/zoneinfo | mysql -u root mysql

*Note `mysql_tzinfo_to_sql': mysql-tzinfo-to-sql. reads your system's
time zone files and generates SQL statements from them.  *Note `mysql':
mysql. processes those statements to load the time zone tables.

*Note `mysql_tzinfo_to_sql': mysql-tzinfo-to-sql. also can be used to
load a single time zone file or to generate leap second information:

   * To load a single time zone file TZ_FILE that corresponds to a time
     zone name TZ_NAME, invoke *Note `mysql_tzinfo_to_sql':
     mysql-tzinfo-to-sql. like this:

          shell> mysql_tzinfo_to_sql TZ_FILE TZ_NAME | mysql -u root mysql

     With this approach, you must execute a separate command to load
     the time zone file for each named zone that the server needs to
     know about.

   * If your time zone needs to account for leap seconds, initialize
     the leap second information like this, where TZ_FILE is the name
     of your time zone file:

          shell> mysql_tzinfo_to_sql --leap TZ_FILE | mysql -u root mysql

   * After running *Note `mysql_tzinfo_to_sql': mysql-tzinfo-to-sql, it
     is best to restart the server so that it does not continue to use
     any previously cached time zone data.

If your system is one that has no zoneinfo database (for example,
Windows or HP-UX), you can use the package of pre-built time zone
tables that is available for download at the MySQL Developer Zone:

     `http://dev.mysql.com/downloads/timezones.html'

This time zone package contains `.frm', `.MYD', and `.MYI' files for
the `MyISAM' time zone tables. These tables should be part of the
`mysql' database, so you should place the files in the `mysql'
subdirectory of your MySQL server's data directory. The server should
be stopped while you do this and restarted afterward.

*Warning*:

Do not use the downloadable package if your system has a zoneinfo
database. Use the *Note `mysql_tzinfo_to_sql': mysql-tzinfo-to-sql.
utility instead.  Otherwise, you may cause a difference in datetime
handling between MySQL and other applications on your system.

For information about time zone settings in replication setup, please
see *Note replication-features::.


File: manual.info,  Node: time-zone-upgrades,  Next: time-zone-leap-seconds,  Prev: time-zone-support,  Up: time-zone-support

10.6.1 Staying Current with Time Zone Changes
---------------------------------------------

As mentioned earlier, when the time zone rules change, applications
that use the old rules become out of date. To stay current, it is
necessary to make sure that your system uses current time zone
information is used. For MySQL, there are two factors to consider in
staying current:

   * The operating system time affects the value that the MySQL server
     uses for times if its time zone is set to `SYSTEM'. Make sure that
     your operating system is using the latest time zone information.
     For most operating systems, the latest update or service pack
     prepares your system for the time changes. Check the Web site for
     your operating system vendor for an update that addresses the time
     changes.

   * If you replace the system's `/etc/localtime' timezone file with a
     version that uses rules differing from those in effect at *Note
     `mysqld': mysqld. startup, you should restart *Note `mysqld':
     mysqld. so that it uses the updated rules.  Otherwise, *Note
     `mysqld': mysqld. might not notice when the system changes its
     time.

   * If you use named time zones with MySQL, make sure that the time
     zone tables in the `mysql' database are up to date. If your system
     has its own zoneinfo database, you should reload the MySQL time
     zone tables whenever the zoneinfo database is updated, using the
     instructions given earlier in this section. For systems that do
     not have their own zoneinfo database, check the MySQL Developer
     Zone for updates. When a new update is available, download it and
     use it to replace your current time zone tables. *Note `mysqld':
     mysqld. caches time zone information that it looks up, so after
     replacing the time zone tables, you should restart *Note `mysqld':
     mysqld. to make sure that it does not continue to serve outdated
     time zone data.

If you are uncertain whether named time zones are available, for use
either as the server's time zone setting or by clients that set their
own time zone, check whether your time zone tables are empty. The
following query determines whether the table that contains time zone
names has any rows:

     mysql> SELECT COUNT(*) FROM mysql.time_zone_name;
     +----------+
     | COUNT(*) |
     +----------+
     |        0 |
     +----------+

A count of zero indicates that the table is empty. In this case, no one
can be using named time zones, and you don't need to update the tables.
A count greater than zero indicates that the table is not empty and
that its contents are available to be used for named time zone support.
In this case, you should be sure to reload your time zone tables so
that anyone who uses named time zones will get correct query results.

To check whether your MySQL installation is updated properly for a
change in Daylight Saving Time rules, use a test like the one
following. The example uses values that are appropriate for the 2007
DST 1-hour change that occurs in the United States on March 11 at 2 a.m.

The test uses these two queries:

     SELECT CONVERT_TZ('2007-03-11 2:00:00','US/Eastern','US/Central');
     SELECT CONVERT_TZ('2007-03-11 3:00:00','US/Eastern','US/Central');

The two time values indicate the times at which the DST change occurs,
and the use of named time zones requires that the time zone tables be
used. The desired result is that both queries return the same result
(the input time, converted to the equivalent value in the 'US/Central'
time zone).

Before updating the time zone tables, you would see an incorrect result
like this:

     mysql> SELECT CONVERT_TZ('2007-03-11 2:00:00','US/Eastern','US/Central');
     +------------------------------------------------------------+
     | CONVERT_TZ('2007-03-11 2:00:00','US/Eastern','US/Central') |
     +------------------------------------------------------------+
     | 2007-03-11 01:00:00                                        |
     +------------------------------------------------------------+

     mysql> SELECT CONVERT_TZ('2007-03-11 3:00:00','US/Eastern','US/Central');
     +------------------------------------------------------------+
     | CONVERT_TZ('2007-03-11 3:00:00','US/Eastern','US/Central') |
     +------------------------------------------------------------+
     | 2007-03-11 02:00:00                                        |
     +------------------------------------------------------------+

After updating the tables, you should see the correct result:

     mysql> SELECT CONVERT_TZ('2007-03-11 2:00:00','US/Eastern','US/Central');
     +------------------------------------------------------------+
     | CONVERT_TZ('2007-03-11 2:00:00','US/Eastern','US/Central') |
     +------------------------------------------------------------+
     | 2007-03-11 01:00:00                                        |
     +------------------------------------------------------------+

     mysql> SELECT CONVERT_TZ('2007-03-11 3:00:00','US/Eastern','US/Central');
     +------------------------------------------------------------+
     | CONVERT_TZ('2007-03-11 3:00:00','US/Eastern','US/Central') |
     +------------------------------------------------------------+
     | 2007-03-11 01:00:00                                        |
     +------------------------------------------------------------+


File: manual.info,  Node: time-zone-leap-seconds,  Prev: time-zone-upgrades,  Up: time-zone-support

10.6.2 Time Zone Leap Second Support
------------------------------------

Before MySQL 5.0.74, if the operating system is configured to return
leap seconds from OS time calls or if the MySQL server uses a time zone
definition that has leap seconds, functions such as `NOW()' could
return a value having a time part that ends with `:59:60' or `:59:61'.
If such values are inserted into a table, they would be dumped as is by
*Note `mysqldump': mysqldump. but considered invalid when reloaded,
leading to backup/restore problems.

As of MySQL 5.0.74, leap second values are returned with a time part
that ends with `:59:59'. This means that a function such as `NOW()' can
return the same value for two or three consecutive seconds during the
leap second. It remains true that literal temporal values having a time
part that ends with `:59:60' or `:59:61' are considered invalid.

If it is necessary to search for *Note `TIMESTAMP': datetime. values
one second before the leap second, anomalous results may be obtained if
you use a comparison with `'YYYY-MM-DD hh:mm:ss'' values:

     mysql> CREATE TABLE t1 (a INT, ts TIMESTAMP DEFAULT NOW(), PRIMARY KEY (ts));
     Query OK, 0 rows affected (0.11 sec)

     mysql> # Simulate NOW() = '2009-01-01 02:59:59'
     mysql> SET timestamp = 1230768022;
     Query OK, 0 rows affected (0.00 sec)

     mysql> INSERT INTO t1 (a) VALUES (1);
     Query OK, 1 row affected (0.07 sec)

     mysql> # Simulate NOW() = '2009-01-01 02:59:60'
     mysql> SET timestamp = 1230768023;
     Query OK, 0 rows affected (0.00 sec)

     mysql> INSERT INTO t1 (a) VALUES (2);
     Query OK, 1 row affected (0.02 sec)

     mysql> SELECT * FROM t1;
     +------+---------------------+
     | a    | ts                  |
     +------+---------------------+
     |    1 | 2008-12-31 18:00:22 |
     |    2 | 2008-12-31 18:00:23 |
     +------+---------------------+
     2 rows in set (0.02 sec)

     mysql> SELECT * FROM t1 WHERE ts = '2009-01-01 02:59:59';
     Empty set (0.03 sec)

To work around this, you can use a comparison based on the UTC value
actually stored in column, which has the leap second correction applied:

     mysql> SELECT * FROM t1 WHERE UNIX_TIMESTAMP(ts) = 1230768023;
     +------+---------------------+
     | a    | ts                  |
     +------+---------------------+
     |    2 | 2008-12-31 18:00:23 |
     +------+---------------------+
     1 row in set (0.02 sec)


File: manual.info,  Node: locale-support,  Prev: time-zone-support,  Up: globalization

10.7 MySQL Server Locale Support
================================

Beginning with MySQL 5.0.25, the locale indicated by the
`lc_time_names' system variable controls the language used to display
day and month names and abbreviations. This variable affects the output
from the `DATE_FORMAT()', `DAYNAME()', and `MONTHNAME()' functions.

Locale names have language and region subtags listed by IANA
(`http://www.iana.org/assignments/language-subtag-registry') such as
`'ja_JP'' or `'pt_BR''.  The default value is `'en_US'' regardless of
your system's locale setting, but you can set the value at server
startup or set the `GLOBAL' value if you have the `SUPER' privilege.
Any client can examine the value of `lc_time_names' or set its
`SESSION' value to affect the locale for its own connection.

     mysql> SET NAMES 'utf8';
     Query OK, 0 rows affected (0.09 sec)

     mysql> SELECT @@lc_time_names;
     +-----------------+
     | @@lc_time_names |
     +-----------------+
     | en_US           |
     +-----------------+
     1 row in set (0.00 sec)

     mysql> SELECT DAYNAME('2010-01-01'), MONTHNAME('2010-01-01');
     +-----------------------+-------------------------+
     | DAYNAME('2010-01-01') | MONTHNAME('2010-01-01') |
     +-----------------------+-------------------------+
     | Friday                | January                 |
     +-----------------------+-------------------------+
     1 row in set (0.00 sec)

     mysql> SELECT DATE_FORMAT('2010-01-01','%W %a %M %b');
     +-----------------------------------------+
     | DATE_FORMAT('2010-01-01','%W %a %M %b') |
     +-----------------------------------------+
     | Friday Fri January Jan                  |
     +-----------------------------------------+
     1 row in set (0.00 sec)

     mysql> SET lc_time_names = 'es_MX';
     Query OK, 0 rows affected (0.00 sec)

     mysql> SELECT @@lc_time_names;
     +-----------------+
     | @@lc_time_names |
     +-----------------+
     | es_MX           |
     +-----------------+
     1 row in set (0.00 sec)

     mysql> SELECT DAYNAME('2010-01-01'), MONTHNAME('2010-01-01');
     +-----------------------+-------------------------+
     | DAYNAME('2010-01-01') | MONTHNAME('2010-01-01') |
     +-----------------------+-------------------------+
     | viernes               | enero                   |
     +-----------------------+-------------------------+
     1 row in set (0.00 sec)

     mysql> SELECT DATE_FORMAT('2010-01-01','%W %a %M %b');
     +-----------------------------------------+
     | DATE_FORMAT('2010-01-01','%W %a %M %b') |
     +-----------------------------------------+
     | viernes vie enero ene                   |
     +-----------------------------------------+
     1 row in set (0.00 sec)

The day or month name for each of the affected functions is converted
from `utf8' to the character set indicated by the
`character_set_connection' system variable.

`lc_time_names' may be set to any of the following locale values. The
set of locales supported by MySQL may differ from those supported by
your operating system.

`ar_AE': Arabic - United Arab        `ar_BH': Arabic - Bahrain
Emirates                             
`ar_DZ': Arabic - Algeria            `ar_EG': Arabic - Egypt
`ar_IN': Arabic - India              `ar_IQ': Arabic - Iraq
`ar_JO': Arabic - Jordan             `ar_KW': Arabic - Kuwait
`ar_LB': Arabic - Lebanon            `ar_LY': Arabic - Libya
`ar_MA': Arabic - Morocco            `ar_OM': Arabic - Oman
`ar_QA': Arabic - Qatar              `ar_SA': Arabic - Saudi Arabia
`ar_SD': Arabic - Sudan              `ar_SY': Arabic - Syria
`ar_TN': Arabic - Tunisia            `ar_YE': Arabic - Yemen
`be_BY': Belarusian - Belarus        `bg_BG': Bulgarian - Bulgaria
`ca_ES': Catalan - Spain             `cs_CZ': Czech - Czech Republic
`da_DK': Danish - Denmark            `de_AT': German - Austria
`de_BE': German - Belgium            `de_CH': German - Switzerland
`de_DE': German - Germany            `de_LU': German - Luxembourg
`en_AU': English - Australia         `en_CA': English - Canada
`en_GB': English - United Kingdom    `en_IN': English - India
`en_NZ': English - New Zealand       `en_PH': English - Philippines
`en_US': English - United States     `en_ZA': English - South Africa
`en_ZW': English - Zimbabwe          `es_AR': Spanish - Argentina
`es_BO': Spanish - Bolivia           `es_CL': Spanish - Chile
`es_CO': Spanish - Columbia          `es_CR': Spanish - Costa Rica
`es_DO': Spanish - Dominican         `es_EC': Spanish - Ecuador
Republic                             
`es_ES': Spanish - Spain             `es_GT': Spanish - Guatemala
`es_HN': Spanish - Honduras          `es_MX': Spanish - Mexico
`es_NI': Spanish - Nicaragua         `es_PA': Spanish - Panama
`es_PE': Spanish - Peru              `es_PR': Spanish - Puerto Rico
`es_PY': Spanish - Paraguay          `es_SV': Spanish - El Salvador
`es_US': Spanish - United States     `es_UY': Spanish - Uruguay
`es_VE': Spanish - Venezuela         `et_EE': Estonian - Estonia
`eu_ES': Basque - Basque             `fi_FI': Finnish - Finland
`fo_FO': Faroese - Faroe Islands     `fr_BE': French - Belgium
`fr_CA': French - Canada             `fr_CH': French - Switzerland
`fr_FR': French - France             `fr_LU': French - Luxembourg
`gl_ES': Galician - Spain            `gu_IN': Gujarati - India
`he_IL': Hebrew - Israel             `hi_IN': Hindi - India
`hr_HR': Croatian - Croatia          `hu_HU': Hungarian - Hungary
`id_ID': Indonesian - Indonesia      `is_IS': Icelandic - Iceland
`it_CH': Italian - Switzerland       `it_IT': Italian - Italy
`ja_JP': Japanese - Japan            `ko_KR': Korean - Republic of Korea
`lt_LT': Lithuanian - Lithuania      `lv_LV': Latvian - Latvia
`mk_MK': Macedonian - FYROM          `mn_MN': Mongolia - Mongolian
`ms_MY': Malay - Malaysia            `nb_NO': Norwegian(Bokmaal) - Norway
`nl_BE': Dutch - Belgium             `nl_NL': Dutch - The Netherlands
`no_NO': Norwegian - Norway          `pl_PL': Polish - Poland
`pt_BR': Portugese - Brazil          `pt_PT': Portugese - Portugal
`ro_RO': Romanian - Romania          `ru_RU': Russian - Russia
`ru_UA': Russian - Ukraine           `sk_SK': Slovak - Slovakia
`sl_SI': Slovenian - Slovenia        `sq_AL': Albanian - Albania
`sr_YU': Serbian - Yugoslavia        `sv_FI': Swedish - Finland
`sv_SE': Swedish - Sweden            `ta_IN': Tamil - India
`te_IN': Telugu - India              `th_TH': Thai - Thailand
`tr_TR': Turkish - Turkey            `uk_UA': Ukrainian - Ukraine
`ur_PK': Urdu - Pakistan             `vi_VN': Vietnamese - Viet Nam
`zh_CN': Chinese - China             `zh_HK': Chinese - Hong Kong
`zh_TW': Chinese - Taiwan Province   
of China                             

`lc_time_names' currently does not affect the `STR_TO_DATE()' or
`GET_FORMAT()' function.


File: manual.info,  Node: data-types,  Next: functions,  Prev: globalization,  Up: Top

11 Data Types
*************

* Menu:

* data-type-overview::           Data Type Overview
* numeric-types::                Numeric Types
* date-and-time-types::          Date and Time Types
* string-types::                 String Types
* storage-requirements::         Data Type Storage Requirements
* choosing-types::               Choosing the Right Type for a Column
* other-vendor-data-types::      Using Data Types from Other Database Engines

MySQL supports a number of data types in several categories: numeric
types, date and time types, and string (character and byte) types.
This chapter provides an overview of these data types, a more detailed
description of the properties of the types in each category, and a
summary of the data type storage requirements. The initial overview is
intentionally brief. The more detailed descriptions later in the
chapter should be consulted for additional information about particular
data types, such as the permissible formats in which you can specify
values.

MySQL also supports extensions for handing spatial data. For
information about these data types, see *Note spatial-extensions::.

Data type descriptions use these conventions:

   * M indicates the maximum display width for integer types. For
     floating-point and fixed-point types, M is the total number of
     digits that can be stored (the precision). For string types, M is
     the maximum length. The maximum permissible value of M depends on
     the data type.

   * D applies to floating-point and fixed-point types and indicates
     the number of digits following the decimal point (the scale). The
     maximum possible value is 30, but should be no greater than M-2.

   * Square brackets (``['' and ``]'') indicate optional parts of type
     definitions.


File: manual.info,  Node: data-type-overview,  Next: numeric-types,  Prev: data-types,  Up: data-types

11.1 Data Type Overview
=======================

* Menu:

* numeric-type-overview::        Numeric Type Overview
* date-and-time-type-overview::  Date and Time Type Overview
* string-type-overview::         String Type Overview
* data-type-defaults::           Data Type Default Values


File: manual.info,  Node: numeric-type-overview,  Next: date-and-time-type-overview,  Prev: data-type-overview,  Up: data-type-overview

11.1.1 Numeric Type Overview
----------------------------

A summary of the numeric data types follows. For additional information
about properties and storage requirements of the numeric types, see
*Note numeric-types::, and *Note storage-requirements::.

M indicates the maximum display width for integer types. The maximum
legal display width is 255.  Display width is unrelated to the range of
values a type can contain, as described in *Note numeric-types::. For
floating-point and fixed-point types, M is the total number of digits
that can be stored.

If you specify `ZEROFILL' for a numeric column, MySQL automatically
adds the `UNSIGNED' attribute to the column.

Numeric data types that permit the `UNSIGNED' attribute also permit
`SIGNED'. However, these data types are signed by default, so the
`SIGNED' attribute has no effect.

`SERIAL' is an alias for `BIGINT UNSIGNED NOT NULL AUTO_INCREMENT
UNIQUE'.

`SERIAL DEFAULT VALUE' in the definition of an integer column is an
alias for `NOT NULL AUTO_INCREMENT UNIQUE'.

*Warning*:

When you use subtraction between integer values where one is of type
`UNSIGNED', the result is unsigned unless the `NO_UNSIGNED_SUBTRACTION'
SQL mode is enabled. See *Note cast-functions::.

   * *Note `BIT[(M)]': numeric-types.

     A bit-field type. M indicates the number of bits per value, from 1
     to 64. The default is 1 if M is omitted.

     This data type was added in MySQL 5.0.3 for `MyISAM', and extended
     in 5.0.5 to `MEMORY', `InnoDB', `BDB', and *Note `NDBCLUSTER':
     mysql-cluster. Before 5.0.3, *Note `BIT': numeric-types. is a
     synonym for `TINYINT(1)'.

   * *Note `TINYINT[(M)] [UNSIGNED] [ZEROFILL]': numeric-types.

     A very small integer. The signed range is `-128' to `127'. The
     unsigned range is `0' to `255'.

   * *Note `BOOL': numeric-types, *Note `BOOLEAN': numeric-types.

     These types are synonyms for *Note `TINYINT(1)': numeric-types. A
     value of zero is considered false. Nonzero values are considered
     true:

          mysql> SELECT IF(0, 'true', 'false');
          +------------------------+
          | IF(0, 'true', 'false') |
          +------------------------+
          | false                  |
          +------------------------+

          mysql> SELECT IF(1, 'true', 'false');
          +------------------------+
          | IF(1, 'true', 'false') |
          +------------------------+
          | true                   |
          +------------------------+

          mysql> SELECT IF(2, 'true', 'false');
          +------------------------+
          | IF(2, 'true', 'false') |
          +------------------------+
          | true                   |
          +------------------------+

     However, the values `TRUE' and `FALSE' are merely aliases for `1'
     and `0', respectively, as shown here:

          mysql> SELECT IF(0 = FALSE, 'true', 'false');
          +--------------------------------+
          | IF(0 = FALSE, 'true', 'false') |
          +--------------------------------+
          | true                           |
          +--------------------------------+

          mysql> SELECT IF(1 = TRUE, 'true', 'false');
          +-------------------------------+
          | IF(1 = TRUE, 'true', 'false') |
          +-------------------------------+
          | true                          |
          +-------------------------------+

          mysql> SELECT IF(2 = TRUE, 'true', 'false');
          +-------------------------------+
          | IF(2 = TRUE, 'true', 'false') |
          +-------------------------------+
          | false                         |
          +-------------------------------+

          mysql> SELECT IF(2 = FALSE, 'true', 'false');
          +--------------------------------+
          | IF(2 = FALSE, 'true', 'false') |
          +--------------------------------+
          | false                          |
          +--------------------------------+

     The last two statements display the results shown because `2' is
     equal to neither `1' nor `0'.

   * *Note `SMALLINT[(M)] [UNSIGNED] [ZEROFILL]': numeric-types.

     A small integer. The signed range is `-32768' to `32767'. The
     unsigned range is `0' to `65535'.

   * *Note `MEDIUMINT[(M)] [UNSIGNED] [ZEROFILL]': numeric-types.

     A medium-sized integer. The signed range is `-8388608' to
     `8388607'.  The unsigned range is `0' to `16777215'.

   * *Note `INT[(M)] [UNSIGNED] [ZEROFILL]': numeric-types.

     A normal-size integer. The signed range is `-2147483648' to
     `2147483647'. The unsigned range is `0' to `4294967295'.

   * *Note `INTEGER[(M)] [UNSIGNED] [ZEROFILL]': numeric-types.

     This type is a synonym for *Note `INT': numeric-types.

   * *Note `BIGINT[(M)] [UNSIGNED] [ZEROFILL]': numeric-types.

     A large integer. The signed range is `-9223372036854775808' to
     `9223372036854775807'. The unsigned range is `0' to
     `18446744073709551615'.

     `SERIAL' is an alias for `BIGINT UNSIGNED NOT NULL AUTO_INCREMENT
     UNIQUE'.

     Some things you should be aware of with respect to *Note `BIGINT':
     numeric-types. columns:

        * All arithmetic is done using signed *Note `BIGINT':
          numeric-types. or *Note `DOUBLE': numeric-types. values, so
          you should not use unsigned big integers larger than
          `9223372036854775807' (63 bits) except with bit functions! If
          you do that, some of the last digits in the result may be
          wrong because of rounding errors when converting a *Note
          `BIGINT': numeric-types. value to a *Note `DOUBLE':
          numeric-types.

          MySQL can handle *Note `BIGINT': numeric-types.  in the
          following cases:

             * When using integers to store large unsigned values in a
               *Note `BIGINT': numeric-types. column.

             * In `MIN(COL_NAME)' or `MAX(COL_NAME)', where COL_NAME
               refers to a *Note `BIGINT': numeric-types. column.

             * When using operators (`+', `-', `*', and so on) where
               both operands are integers.

        * You can always store an exact integer value in a *Note
          `BIGINT': numeric-types. column by storing it using a string.
          In this case, MySQL performs a string-to-number conversion
          that involves no intermediate double-precision representation.

        * The `-', `+', and `*' operators use *Note `BIGINT':
          numeric-types.  arithmetic when both operands are integer
          values. This means that if you multiply two big integers (or
          results from functions that return integers), you may get
          unexpected results when the result is larger than
          `9223372036854775807'.

   * *Note `DECIMAL[(M[,D])] [UNSIGNED] [ZEROFILL]': numeric-types.

     For MySQL 5.0.3 and above:

     A packed `exact' fixed-point number.  M is the total number of
     digits (the precision) and D is the number of digits after the
     decimal point (the scale). The decimal point and (for negative
     numbers) the ``-'' sign are not counted in M. If D is 0, values
     have no decimal point or fractional part. The maximum number of
     digits (M) for *Note `DECIMAL': numeric-types. is 65 (64 from 5.0.3
     to 5.0.5). The maximum number of supported decimals (D) is 30. If
     D is omitted, the default is 0.  If M is omitted, the default is
     10.

     `UNSIGNED', if specified, disallows negative values.

     All basic calculations (`+, -, *, /') with *Note `DECIMAL':
     numeric-types. columns are done with a precision of 65 digits.

     Before MySQL 5.0.3:

     An unpacked fixed-point number. Behaves like a *Note `CHAR': char.
     column; `unpacked' means the number is stored as a string, using
     one character for each digit of the value.  M is the total number
     of digits and D is the number of digits after the decimal point.
     The decimal point and (for negative numbers) the ``-'' sign are
     not counted in M, although space for them is reserved. If D is 0,
     values have no decimal point or fractional part. The maximum range
     of *Note `DECIMAL': numeric-types. values is the same as for *Note
     `DOUBLE': numeric-types, but the actual range for a given *Note
     `DECIMAL': numeric-types. column may be constrained by the choice
     of M and D. If D is omitted, the default is 0.  If M is omitted,
     the default is 10.

     `UNSIGNED', if specified, disallows negative values.

     The behavior used by the server for *Note `DECIMAL':
     numeric-types. columns in a table depends on the version of MySQL
     used to create the table. If your server is from MySQL 5.0.3 or
     higher, but you have *Note `DECIMAL': numeric-types. columns in
     tables that were created before 5.0.3, the old behavior still
     applies to those columns. To convert the tables to the newer *Note
     `DECIMAL': numeric-types. format, dump them with *Note
     `mysqldump': mysqldump. and reload them.

   * *Note `DEC[(M[,D])] [UNSIGNED] [ZEROFILL]': numeric-types, *Note
     `NUMERIC[(M[,D])] [UNSIGNED] [ZEROFILL]': numeric-types, *Note
     `FIXED[(M[,D])] [UNSIGNED] [ZEROFILL]': numeric-types.

     These types are synonyms for *Note `DECIMAL': numeric-types. The
     *Note `FIXED': numeric-types. synonym is available for
     compatibility with other database systems.

   * *Note `FLOAT[(M,D)] [UNSIGNED] [ZEROFILL]': numeric-types.

     A small (single-precision) floating-point number.  Permissible
     values are `-3.402823466E+38' to `-1.175494351E-38', `0', and
     `1.175494351E-38' to `3.402823466E+38'. These are the theoretical
     limits, based on the IEEE standard. The actual range might be
     slightly smaller depending on your hardware or operating system.

     M is the total number of digits and D is the number of digits
     following the decimal point. If M and D are omitted, values are
     stored to the limits permitted by the hardware. A single-precision
     floating-point number is accurate to approximately 7 decimal
     places.

     `UNSIGNED', if specified, disallows negative values.

     Using *Note `FLOAT': numeric-types. might give you some unexpected
     problems because all calculations in MySQL are done with double
     precision. See *Note no-matching-rows::.

   * *Note `DOUBLE[(M,D)] [UNSIGNED] [ZEROFILL]': numeric-types.

     A normal-size (double-precision) floating-point number.
     Permissible values are `-1.7976931348623157E+308' to
     `-2.2250738585072014E-308', `0', and `2.2250738585072014E-308' to
     `1.7976931348623157E+308'. These are the theoretical limits, based
     on the IEEE standard. The actual range might be slightly smaller
     depending on your hardware or operating system.

     M is the total number of digits and D is the number of digits
     following the decimal point. If M and D are omitted, values are
     stored to the limits permitted by the hardware. A double-precision
     floating-point number is accurate to approximately 15 decimal
     places.

     `UNSIGNED', if specified, disallows negative values.

   * *Note `DOUBLE PRECISION[(M,D)] [UNSIGNED] [ZEROFILL]':
     numeric-types, *Note `REAL[(M,D)] [UNSIGNED] [ZEROFILL]':
     numeric-types.

     These types are synonyms for *Note `DOUBLE': numeric-types.
     Exception: If the `REAL_AS_FLOAT' SQL mode is enabled, *Note
     `REAL': numeric-types. is a synonym for *Note `FLOAT':
     numeric-types. rather than *Note `DOUBLE': numeric-types.

   * *Note `FLOAT(P) [UNSIGNED] [ZEROFILL]': numeric-types.

     A floating-point number. P represents the precision in bits, but
     MySQL uses this value only to determine whether to use *Note
     `FLOAT': numeric-types. or *Note `DOUBLE': numeric-types. for the
     resulting data type. If P is from 0 to 24, the data type becomes
     *Note `FLOAT': numeric-types. with no M or D values. If P is from
     25 to 53, the data type becomes *Note `DOUBLE': numeric-types.
     with no M or D values. The range of the resulting column is the
     same as for the single-precision *Note `FLOAT': numeric-types. or
     double-precision *Note `DOUBLE': numeric-types. data types
     described earlier in this section.

     *Note `FLOAT(P)': numeric-types.  syntax is provided for ODBC
     compatibility.


File: manual.info,  Node: date-and-time-type-overview,  Next: string-type-overview,  Prev: numeric-type-overview,  Up: data-type-overview

11.1.2 Date and Time Type Overview
----------------------------------

A summary of the temporal data types follows. For additional
information about properties and storage requirements of the temporal
types, see *Note date-and-time-types::, and *Note
storage-requirements::. For descriptions of functions that operate on
temporal values, see *Note date-and-time-functions::.

For the *Note `DATE': datetime. and *Note `DATETIME': datetime. range
descriptions, `supported' means that although earlier values might
work, there is no guarantee.

   * *Note `DATE': datetime.

     A date. The supported range is `'1000-01-01'' to `'9999-12-31''.
     MySQL displays *Note `DATE': datetime. values in `'YYYY-MM-DD''
     format, but permits assignment of values to *Note `DATE': datetime.
     columns using either strings or numbers.

   * *Note `DATETIME': datetime.

     A date and time combination. The supported range is `'1000-01-01
     00:00:00'' to `'9999-12-31 23:59:59''. MySQL displays *Note
     `DATETIME': datetime. values in `'YYYY-MM-DD HH:MM:SS'' format,
     but permits assignment of values to *Note `DATETIME': datetime.
     columns using either strings or numbers.

   * *Note `TIMESTAMP': datetime.

     A timestamp. The range is `'1970-01-01 00:00:01'' UTC to
     `'2038-01-19 03:14:07'' UTC.  *Note `TIMESTAMP': datetime. values
     are stored as the number of seconds since the epoch (`'1970-01-01
     00:00:00'' UTC). A *Note `TIMESTAMP': datetime. cannot represent
     the value `'1970-01-01 00:00:00'' because that is equivalent to 0
     seconds from the epoch and the value 0 is reserved for
     representing `'0000-00-00 00:00:00'', the `zero' *Note
     `TIMESTAMP': datetime. value.

     MySQL displays *Note `TIMESTAMP': datetime.  values in
     `'YYYY-MM-DD HH:MM:SS'' format.  To convert the value to a number,
     add `+0'.

     A *Note `TIMESTAMP': datetime. column is useful for recording the
     date and time of an *Note `INSERT': insert. or *Note `UPDATE':
     update. operation. By default, the first *Note `TIMESTAMP':
     datetime. column in a table is automatically set to the date and
     time of the most recent operation if you do not assign it a value
     yourself. You can also set any *Note `TIMESTAMP': datetime. column
     to the current date and time by assigning it a `NULL' value. The
     automatic initialization and update properties can be specified
     using `DEFAULT' and `ON UPDATE' clauses, are described in *Note
     timestamp::.

     *Note*:

     The *Note `TIMESTAMP': datetime. format that was used prior to
     MySQL 4.1 is not supported in MySQL 5.0; see `MySQL 3.23, 4.0, 4.1
     Reference Manual' for information regarding the old format.

   * *Note `TIME': time.

     A time. The range is `'-838:59:59'' to `'838:59:59''. MySQL
     displays *Note `TIME': time. values in `'HH:MM:SS'' format, but
     permits assignment of values to *Note `TIME': time. columns using
     either strings or numbers.

   * *Note `YEAR[(2|4)]': year.

     A year in two-digit or four-digit format. The default is
     four-digit format. In four-digit format, the permissible values
     are `1901' to `2155', and `0000'. In two-digit format, the
     permissible values are `70' to `69', representing years from 1970
     to 2069. MySQL displays *Note `YEAR': year. values in `YYYY'
     format, but permits assignment of values to *Note `YEAR': year.
     columns using either strings or numbers.

The `SUM()' and `AVG()' aggregate functions do not work with temporal
values. (They convert the values to numbers, which loses the part after
the first nonnumeric character.) To work around this problem, convert
to numeric units, perform the aggregate operation, and convert back to
a temporal value.  Examples:

     SELECT SEC_TO_TIME(SUM(TIME_TO_SEC(TIME_COL))) FROM TBL_NAME;
     SELECT FROM_DAYS(SUM(TO_DAYS(DATE_COL))) FROM TBL_NAME;


File: manual.info,  Node: string-type-overview,  Next: data-type-defaults,  Prev: date-and-time-type-overview,  Up: data-type-overview

11.1.3 String Type Overview
---------------------------

A summary of the string data types follows. For additional information
about properties and storage requirements of the string types, see
*Note string-types::, and *Note storage-requirements::.

In some cases, MySQL may change a string column to a type different
from that given in a *Note `CREATE TABLE': create-table. or *Note
`ALTER TABLE': alter-table.  statement. See *Note
silent-column-changes::.

In MySQL 4.1 and up, string data types include some features that you
may not have encountered in working with versions of MySQL prior to 4.1:

   * MySQL interprets length specifications in character column
     definitions in character units. (Before MySQL 4.1, column lengths
     were interpreted in bytes.) This applies to *Note `CHAR': char,
     *Note `VARCHAR': char, and the *Note `TEXT': blob. types.

   * Column definitions for many string data types can include
     attributes that specify the character set or collation of the
     column. These attributes apply to the *Note `CHAR': char, *Note
     `VARCHAR': char, the *Note `TEXT': blob. types, *Note `ENUM':
     enum, and *Note `SET': set. data types:

        * The `CHARACTER SET' attribute specifies the character set,
          and the `COLLATE' attribute specifies a collation for the
          character set.  For example:

               CREATE TABLE t
               (
                   c1 VARCHAR(20) CHARACTER SET utf8,
                   c2 TEXT CHARACTER SET latin1 COLLATE latin1_general_cs
               );

          This table definition creates a column named `c1' that has a
          character set of `utf8' with the default collation for that
          character set, and a column named `c2' that has a character
          set of `latin1' and a case-sensitive collation.

          The rules for assigning the character set and collation when
          either or both of the `CHARACTER SET' and `COLLATE' attributes
          are missing are described in *Note charset-column::.

          `CHARSET' is a synonym for `CHARACTER SET'.

        * Specifying the `CHARACTER SET binary' attribute for a
          character data type causes the column to be created as the
          corresponding binary data type: *Note `CHAR': char. becomes
          *Note `BINARY': binary-varbinary, *Note `VARCHAR': char.
          becomes *Note `VARBINARY': binary-varbinary, and *Note
          `TEXT': blob. becomes *Note `BLOB': blob. For the *Note
          `ENUM': enum. and *Note `SET': set. data types, this does not
          occur; they are created as declared. Suppose that you specify
          a table using this definition:

               CREATE TABLE t
               (
                 c1 VARCHAR(10) CHARACTER SET binary,
                 c2 TEXT CHARACTER SET binary,
                 c3 ENUM('a','b','c') CHARACTER SET binary
               );

          The resulting table has this definition:

               CREATE TABLE t
               (
                 c1 VARBINARY(10),
                 c2 BLOB,
                 c3 ENUM('a','b','c') CHARACTER SET binary
               );

        * The `ASCII' attribute is shorthand for `CHARACTER SET latin1'.

        * The `UNICODE' attribute is shorthand for `CHARACTER SET ucs2'.

        * The `BINARY' attribute is shorthand for specifying the binary
          collation of the column character set. In this case, sorting
          and comparison are based on numeric character values. (Before
          MySQL 4.1, `BINARY' caused a column to store binary strings
          and sorting and comparison were based on numeric byte values.
          This is the same as using character values for single-byte
          character sets, but not for multi-byte character sets.)

   * Character column sorting and comparison are based on the character
     set assigned to the column. (Before MySQL 4.1, sorting and
     comparison were based on the collation of the server character
     set.) For the *Note `CHAR': char, *Note `VARCHAR': char, *Note
     `TEXT': blob, *Note `ENUM': enum, and *Note `SET': set. data
     types, you can declare a column with a binary collation or the
     `BINARY' attribute to cause sorting and comparison to use the
     underlying character code values rather than a lexical ordering.

*Note charset::, provides additional information about use of character
sets in MySQL.

   * `[NATIONAL] CHAR[(M)] [CHARACTER SET CHARSET_NAME] [COLLATE
     COLLATION_NAME]'

     A fixed-length string that is always right-padded with spaces to
     the specified length when stored.  M represents the column length
     in characters. The range of M is 0 to 255. If M is omitted, the
     length is 1.

     *Note*:

     Trailing spaces are removed when *Note `CHAR': char. values are
     retrieved.

     Before MySQL 5.0.3, a *Note `CHAR': char.  column with a length
     specification greater than 255 is converted to the smallest *Note
     `TEXT': blob. type that can hold values of the given length. For
     example, `CHAR(500)' is converted to *Note `TEXT': blob, and
     `CHAR(200000)' is converted to *Note `MEDIUMTEXT': blob. However,
     this conversion causes the column to become a variable-length
     column, and also affects trailing-space removal.

     In MySQL 5.0.3 and later, a *Note `CHAR': char. length greater
     than 255 is illegal and fails with an error:

          mysql> CREATE TABLE c1 (col1 INT, col2 CHAR(500));
          ERROR 1074 (42000): Column length too big for column 'col' (max = 255);
          use BLOB or TEXT instead

     *Note `CHAR': char. is shorthand for *Note `CHARACTER': char.
     *Note `NATIONAL CHAR': char. (or its equivalent short form, *Note
     `NCHAR': char.)  is the standard SQL way to define that a *Note
     `CHAR': char. column should use some predefined character set.
     MySQL 4.1 and up uses `utf8' as this predefined character set.
     *Note charset-national::.

     The *Note `CHAR BYTE': binary-varbinary. data type is an alias for
     the *Note `BINARY': binary-varbinary. data type. This is a
     compatibility feature.

     MySQL permits you to create a column of type `CHAR(0)'. This is
     useful primarily when you have to be compliant with old
     applications that depend on the existence of a column but that do
     not actually use its value. `CHAR(0)' is also quite nice when you
     need a column that can take only two values: A column that is
     defined as `CHAR(0) NULL' occupies only one bit and can take only
     the values `NULL' and `''' (the empty string).

   * `[NATIONAL] VARCHAR(M) [CHARACTER SET CHARSET_NAME] [COLLATE
     COLLATION_NAME]'

     A variable-length string. M represents the maximum column length
     in characters. In MySQL 5.0, the range of M is 0 to 255 before
     MySQL 5.0.3, and 0 to 65,535 in MySQL 5.0.3 and later. The
     effective maximum length of a *Note `VARCHAR': char. in MySQL
     5.0.3 and later is subject to the maximum row size (65,535 bytes,
     which is shared among all columns) and the character set used. For
     example, `utf8' characters can require up to three bytes per
     character, so a *Note `VARCHAR': char. column that uses the `utf8'
     character set can be declared to be a maximum of 21,844
     characters. See *Note column-count-limit::.

     MySQL stores *Note `VARCHAR': char. values as a one-byte or
     two-byte length prefix plus data. The length prefix indicates the
     number of bytes in the value. A *Note `VARCHAR': char. column uses
     one length byte if values require no more than 255 bytes, two
     length bytes if values may require more than 255 bytes.

     *Note*:

     Before 5.0.3, trailing spaces were removed when *Note `VARCHAR':
     char. values were stored, which differs from the standard SQL
     specification.

     Prior to MySQL 5.0.3, a *Note `VARCHAR': char. column with a length
     specification greater than 255 is converted to the smallest *Note
     `TEXT': blob. type that can hold values of the given length. For
     example, `VARCHAR(500)' is converted to *Note `TEXT': blob, and
     `VARCHAR(200000)' is converted to *Note `MEDIUMTEXT': blob.
     However, this conversion affects trailing-space removal.

     *Note `VARCHAR': char. is shorthand for *Note `CHARACTER VARYING':
     char.  *Note `NATIONAL VARCHAR': char. is the standard SQL way to
     define that a *Note `VARCHAR': char. column should use some
     predefined character set. MySQL 4.1 and up uses `utf8' as this
     predefined character set.  *Note charset-national::.  *Note
     `NVARCHAR': char. is shorthand for *Note `NATIONAL VARCHAR': char.

   * *Note `BINARY(M)': binary-varbinary.

     The *Note `BINARY': binary-varbinary. type is similar to the *Note
     `CHAR': char. type, but stores binary byte strings rather than
     nonbinary character strings.  M represents the column length in
     bytes.

   * *Note `VARBINARY(M)': binary-varbinary.

     The *Note `VARBINARY': binary-varbinary. type is similar to the
     *Note `VARCHAR': char. type, but stores binary byte strings rather
     than nonbinary character strings. M represents the maximum column
     length in bytes.

   * *Note `TINYBLOB': blob.

     A *Note `BLOB': blob. column with a maximum length of 255 (2^8 - 1)
     bytes. Each *Note `TINYBLOB': blob. value is stored using a
     one-byte length prefix that indicates the number of bytes in the
     value.

   * *Note `TINYTEXT [CHARACTER SET CHARSET_NAME] [COLLATE
     COLLATION_NAME]': blob.

     A *Note `TEXT': blob. column with a maximum length of 255 (2^8 - 1)
     characters. The effective maximum length is less if the value
     contains multi-byte characters. Each *Note `TINYTEXT': blob. value
     is stored using a one-byte length prefix that indicates the number
     of bytes in the value.

   * *Note `BLOB[(M)]': blob.

     A *Note `BLOB': blob. column with a maximum length of 65,535 (2^16
     - 1) bytes. Each *Note `BLOB': blob. value is stored using a
     two-byte length prefix that indicates the number of bytes in the
     value.

     An optional length M can be given for this type. If this is done,
     MySQL creates the column as the smallest *Note `BLOB': blob. type
     large enough to hold values M bytes long.

   * *Note `TEXT[(M)] [CHARACTER SET CHARSET_NAME] [COLLATE
     COLLATION_NAME]': blob.

     A *Note `TEXT': blob. column with a maximum length of 65,535 (2^16
     - 1) characters. The effective maximum length is less if the value
     contains multi-byte characters. Each *Note `TEXT': blob. value is
     stored using a two-byte length prefix that indicates the number of
     bytes in the value.

     An optional length M can be given for this type. If this is done,
     MySQL creates the column as the smallest *Note `TEXT': blob. type
     large enough to hold values M characters long.

   * *Note `MEDIUMBLOB': blob.

     A *Note `BLOB': blob. column with a maximum length of 16,777,215
     (2^24 - 1) bytes. Each *Note `MEDIUMBLOB': blob.  value is stored
     using a three-byte length prefix that indicates the number of
     bytes in the value.

   * *Note `MEDIUMTEXT [CHARACTER SET CHARSET_NAME] [COLLATE
     COLLATION_NAME]': blob.

     A *Note `TEXT': blob. column with a maximum length of 16,777,215
     (2^24 - 1) characters. The effective maximum length is less if the
     value contains multi-byte characters. Each *Note `MEDIUMTEXT':
     blob. value is stored using a three-byte length prefix that
     indicates the number of bytes in the value.

   * *Note `LONGBLOB': blob.

     A *Note `BLOB': blob. column with a maximum length of
     4,294,967,295 or 4GB (2^32 - 1) bytes. The effective maximum
     length of *Note `LONGBLOB': blob. columns depends on the
     configured maximum packet size in the client/server protocol and
     available memory. Each *Note `LONGBLOB': blob. value is stored
     using a four-byte length prefix that indicates the number of bytes
     in the value.

   * *Note `LONGTEXT [CHARACTER SET CHARSET_NAME] [COLLATE
     COLLATION_NAME]': blob.

     A *Note `TEXT': blob. column with a maximum length of
     4,294,967,295 or 4GB (2^32 - 1) characters. The effective maximum
     length is less if the value contains multi-byte characters. The
     effective maximum length of *Note `LONGTEXT': blob.  columns also
     depends on the configured maximum packet size in the client/server
     protocol and available memory. Each *Note `LONGTEXT': blob.  value
     is stored using a four-byte length prefix that indicates the
     number of bytes in the value.

   * *Note `ENUM('VALUE1','VALUE2',...) [CHARACTER SET CHARSET_NAME]
     [COLLATE COLLATION_NAME]': enum.

     An enumeration. A string object that can have only one value,
     chosen from the list of values `'VALUE1'', `'VALUE2'', `...',
     `NULL' or the special `''' error value. An *Note `ENUM': enum.
     column can have a maximum of 65,535 distinct values.  *Note
     `ENUM': enum. values are represented internally as integers.

   * *Note `SET('VALUE1','VALUE2',...) [CHARACTER SET CHARSET_NAME]
     [COLLATE COLLATION_NAME]': set.

     A set. A string object that can have zero or more values, each of
     which must be chosen from the list of values `'VALUE1'',
     `'VALUE2'', `...' A *Note `SET': set.  column can have a maximum
     of 64 members.  *Note `SET': set. values are represented
     internally as integers.


File: manual.info,  Node: data-type-defaults,  Prev: string-type-overview,  Up: data-type-overview

11.1.4 Data Type Default Values
-------------------------------

The `DEFAULT VALUE' clause in a data type specification indicates a
default value for a column. With one exception, the default value must
be a constant; it cannot be a function or an expression. This means,
for example, that you cannot set the default for a date column to be
the value of a function such as `NOW()' or `CURRENT_DATE'. The
exception is that you can specify `CURRENT_TIMESTAMP' as the default
for a *Note `TIMESTAMP': datetime. column. See *Note timestamp::.

Prior to MySQL 5.0.2, if a column definition includes no explicit
`DEFAULT' value, MySQL determines the default value as follows:

If the column can take `NULL' as a value, the column is defined with an
explicit `DEFAULT NULL' clause.

If the column cannot take `NULL' as the value, MySQL defines the column
with an explicit `DEFAULT' clause, using the implicit default value for
the column data type. Implicit defaults are defined as follows:

   * For numeric types, the default is `0', with the exception that for
     integer or floating-point types declared with the `AUTO_INCREMENT'
     attribute, the default is the next value in the sequence.

   * For date and time types other than *Note `TIMESTAMP': datetime,
     the default is the appropriate `zero' value for the type. For the
     first *Note `TIMESTAMP': datetime. column in a table, the default
     value is the current date and time. See *Note
     date-and-time-types::.

   * For string types other than *Note `ENUM': enum, the default value
     is the empty string. For *Note `ENUM': enum, the default is the
     first enumeration value.

*Note `BLOB': blob. and *Note `TEXT': blob. columns cannot be assigned a
default value.

As of MySQL 5.0.2, if a column definition includes no explicit
`DEFAULT' value, MySQL determines the default value as follows:

If the column can take `NULL' as a value, the column is defined with an
explicit `DEFAULT NULL' clause. This is the same as before 5.0.2.

If the column cannot take `NULL' as the value, MySQL defines the column
with no explicit `DEFAULT' clause. Exception: If the column is defined
as part of a `PRIMARY KEY' but not explicitly as `NOT NULL', MySQL
creates it as a `NOT NULL' column (because `PRIMARY KEY' columns must
be `NOT NULL'), but also assigns it a `DEFAULT' clause using the
implicit default value. To prevent this, include an explicit `NOT NULL'
in the definition of any `PRIMARY KEY' column.

For data entry for a `NOT NULL' column that has no explicit `DEFAULT'
clause, if an *Note `INSERT': insert. or *Note `REPLACE': replace.
statement includes no value for the column, or an *Note `UPDATE':
update. statement sets the column to `NULL', MySQL handles the column
according to the SQL mode in effect at the time:

   * If strict SQL mode is not enabled, MySQL sets the column to the
     implicit default value for the column data type.

   * If strict mode is enabled, an error occurs for transactional
     tables and the statement is rolled back. For nontransactional
     tables, an error occurs, but if this happens for the second or
     subsequent row of a multiple-row statement, the preceding rows
     will have been inserted.

Suppose that a table `t' is defined as follows:

     CREATE TABLE t (i INT NOT NULL);

In this case, `i' has no explicit default, so in strict mode each of
the following statements produce an error and no row is inserted. When
not using strict mode, only the third statement produces an error; the
implicit default is inserted for the first two statements, but the
third fails because `DEFAULT(i)' cannot produce a value:

     INSERT INTO t VALUES();
     INSERT INTO t VALUES(DEFAULT);
     INSERT INTO t VALUES(DEFAULT(i));

See *Note server-sql-mode::.

For a given table, you can use the *Note `SHOW CREATE TABLE':
show-create-table. statement to see which columns have an explicit
`DEFAULT' clause.

`SERIAL DEFAULT VALUE' in the definition of an integer column is an
alias for `NOT NULL AUTO_INCREMENT UNIQUE'.


File: manual.info,  Node: numeric-types,  Next: date-and-time-types,  Prev: data-type-overview,  Up: data-types

11.2 Numeric Types
==================

* Menu:

* integer-types::                Integer Types (Exact Value)
* fixed-point-types::            Fixed-Point Types (Exact Value)
* floating-point-types::         Floating-Point Types (Approximate Value)
* bit-type::                     Bit-Value Type
* numeric-type-attributes::      Numeric Type Attributes
* out-of-range-and-overflow::    Out-of-Range and Overflow Handling

MySQL supports all standard SQL numeric data types. These types include
the exact numeric data types (*Note `INTEGER': numeric-types, *Note
`SMALLINT': numeric-types, *Note `DECIMAL': numeric-types, and *Note
`NUMERIC': numeric-types.), as well as the approximate numeric data
types (*Note `FLOAT': numeric-types, *Note `REAL': numeric-types, and
*Note `DOUBLE PRECISION': numeric-types.). The keyword *Note `INT':
numeric-types. is a synonym for *Note `INTEGER': numeric-types, and the
keywords *Note `DEC': numeric-types. and `FIXED' are synonyms for *Note
`DECIMAL': numeric-types. MySQL treats *Note `DOUBLE': numeric-types.
as a synonym for *Note `DOUBLE PRECISION': numeric-types. (a nonstandard
extension). MySQL also treats *Note `REAL': numeric-types.  as a
synonym for *Note `DOUBLE PRECISION': numeric-types.  (a nonstandard
variation), unless the `REAL_AS_FLOAT' SQL mode is enabled.

As of MySQL 5.0.3, a *Note `BIT': numeric-types. data type is available
for storing bit-field values. (Before 5.0.3, MySQL interprets *Note
`BIT': numeric-types. as `TINYINT(1)'.) In MySQL 5.0.3, *Note `BIT':
numeric-types. is supported only for `MyISAM'. MySQL 5.0.5 extends
*Note `BIT': numeric-types. support to `MEMORY', `InnoDB', `BDB', and
*Note `NDBCLUSTER': mysql-cluster.

For information about how MySQL handles assignment of out-of-range
values to columns and overflow during expression evaluation, see *Note
out-of-range-and-overflow::.

For information about numeric type storage requirements, see *Note
storage-requirements::.

The data type used for the result of a calculation on numeric operands
depends on the types of the operands and the operations performed on
them. For more information, see *Note arithmetic-functions::.


File: manual.info,  Node: integer-types,  Next: fixed-point-types,  Prev: numeric-types,  Up: numeric-types

11.2.1 Integer Types (Exact Value)
----------------------------------

MySQL supports the SQL standard integer types *Note `INTEGER':
numeric-types. (or *Note `INT': numeric-types.) and *Note `SMALLINT':
numeric-types. As an extension to the standard, MySQL also supports the
integer types *Note `TINYINT': numeric-types, *Note `MEDIUMINT':
numeric-types, and *Note `BIGINT': numeric-types. The following table
shows the required storage and range for each integer type.

Type        Storage     Minimum Value             Maximum Value
            (Bytes)     (Signed/Unsigned)         Signed/Unsigned)
*Note       1           `-128'                    `127'
`TINYINT':                                        
numeric-types.                                      
                        `0'                       `255'
*Note       2           `-32768'                  `32767'
`SMALLINT':                                       
numeric-types.                                      
                        `0'                       `65535'
*Note       3           `-8388608'                `8388607'
`MEDIUMINT':                                      
numeric-types.                                      
                        `0'                       `16777215'
*Note       4           `-2147483648'             `2147483647'
`INT':                                            
numeric-types.                                      
                        `0'                       `4294967295'
*Note       8           `-9223372036854775808'    `9223372036854775807'
`BIGINT':                                         
numeric-types.                                      
                        `0'                       `18446744073709551615'


File: manual.info,  Node: fixed-point-types,  Next: floating-point-types,  Prev: integer-types,  Up: numeric-types

11.2.2 Fixed-Point Types (Exact Value)
--------------------------------------

The *Note `DECIMAL': numeric-types. and *Note `NUMERIC': numeric-types.
types store exact numeric data values. These types are used when it is
important to preserve exact precision, for example with monetary data.
In MySQL, *Note `NUMERIC': numeric-types. is implemented as *Note
`DECIMAL': numeric-types, so the following remarks about *Note
`DECIMAL': numeric-types. apply equally to *Note `NUMERIC':
numeric-types.

As of MySQL 5.0.3, *Note `DECIMAL': numeric-types. values are stored in
binary format. Previously, they were stored as strings, with one
character used for each digit of the value, the decimal point (if the
scale is greater than 0), and the ``-'' sign (for negative numbers).
See *Note precision-math::.

In a *Note `DECIMAL': numeric-types. column declaration, the precision
and scale can be (and usually is) specified; for example:

     salary DECIMAL(5,2)

In this example, `5' is the precision and `2' is the scale. The
precision represents the number of significant digits that are stored
for values, and the scale represents the number of digits that can be
stored following the decimal point.

Standard SQL requires that `DECIMAL(5,2)' be able to store any value
with five digits and two decimals, so values that can be stored in the
`salary' column range from `-999.99' to `999.99'. MySQL enforces this
limit as of MySQL 5.0.3. Before 5.0.3, on the positive end of the
range, the column could actually store numbers up to `9999.99'. (For
positive numbers, MySQL 5.0.2 and earlier used the byte reserved for
the sign to extend the upper end of the range.)

In standard SQL, the syntax `DECIMAL(M)' is equivalent to
`DECIMAL(M,0)'.  Similarly, the syntax *Note `DECIMAL': numeric-types.
is equivalent to `DECIMAL(M,0)', where the implementation is permitted
to decide the value of M. MySQL supports both of these variant forms of
*Note `DECIMAL': numeric-types. syntax.  The default value of M is 10.

If the scale is 0, *Note `DECIMAL': numeric-types. values contain no
decimal point or fractional part.


File: manual.info,  Node: floating-point-types,  Next: bit-type,  Prev: fixed-point-types,  Up: numeric-types

11.2.3 Floating-Point Types (Approximate Value)
-----------------------------------------------

The *Note `FLOAT': numeric-types. and *Note `DOUBLE': numeric-types.
types represent approximate numeric data values. MySQL uses four bytes
for single-precision values and eight bytes for double-precision values.

For *Note `FLOAT': numeric-types, the SQL standard permits an optional
specification of the precision (but not the range of the exponent) in
bits following the keyword *Note `FLOAT': numeric-types. in
parentheses. MySQL also supports this optional precision specification,
but the precision value is used only to determine storage size. A
precision from 0 to 23 results in a four-byte single-precision *Note
`FLOAT': numeric-types. column. A precision from 24 to 53 results in an
eight-byte double-precision *Note `DOUBLE': numeric-types. column.

MySQL permits a nonstandard syntax: `FLOAT(M,D)' or `REAL(M,D)' or
`DOUBLE PRECISION(M,D)'.  Here, ``(M,D)'' means than values can be
stored with up to M digits in total, of which D digits may be after the
decimal point. For example, a column defined as `FLOAT(7,4)' will look
like `-999.9999' when displayed. MySQL performs rounding when storing
values, so if you insert `999.00009' into a `FLOAT(7,4)' column, the
approximate result is `999.0001'.

Because floating-point values are approximate and not stored as exact
values, attempts to treat them as exact in comparisons may lead to
problems. They are also subject to platform or implementation
dependencies. For more information, see *Note problems-with-float::

For maximum portability, code requiring storage of approximate numeric
data values should use *Note `FLOAT': numeric-types. or *Note `DOUBLE
PRECISION': numeric-types. with no specification of precision or number
of digits.


File: manual.info,  Node: bit-type,  Next: numeric-type-attributes,  Prev: floating-point-types,  Up: numeric-types

11.2.4 Bit-Value Type
---------------------

The maximum number of digits for *Note `DECIMAL': numeric-types. is 65
(64 from MySQL 5.0.3 to 5.0.5). Before MySQL 5.0.3, the maximum range of
*Note `DECIMAL': numeric-types. values is the same as for *Note
`DOUBLE': numeric-types, but the actual range for a given *Note
`DECIMAL': numeric-types. column can be constrained by the precision or
scale for a given column. When such a column is assigned a value with
more digits following the decimal point than are permitted by the
specified scale, the value is converted to that scale. (The precise
behavior is operating system-specific, but generally the effect is
truncation to the permissible number of digits.)

As of MySQL 5.0.3, the *Note `BIT': numeric-types. data type is used to
store bit-field values. A type of `BIT(M)' enables storage of M-bit
values.  M can range from 1 to 64.

To specify bit values, `b'VALUE'' notation can be used. VALUE is a
binary value written using zeros and ones. For example, `b'111'' and
`b'10000000'' represent 7 and 128, respectively. See *Note
bit-field-literals::.

If you assign a value to a `BIT(M)' column that is less than M bits
long, the value is padded on the left with zeros. For example,
assigning a value of `b'101'' to a `BIT(6)' column is, in effect, the
same as assigning `b'000101''.


File: manual.info,  Node: numeric-type-attributes,  Next: out-of-range-and-overflow,  Prev: bit-type,  Up: numeric-types

11.2.5 Numeric Type Attributes
------------------------------

MySQL supports an extension for optionally specifying the display width
of integer data types in parentheses following the base keyword for the
type. For example, *Note `INT(4)': numeric-types. specifies an *Note
`INT': numeric-types. with a display width of four digits. This
optional display width may be used by applications to display integer
values having a width less than the width specified for the column by
left-padding them with spaces. (That is, this width is present in the
metadata returned with result sets. Whether it is used or not is up to
the application.)

The display width does _not_ constrain the range of values that can be
stored in the column. Nor does it prevent values wider than the column
display width from being displayed correctly. For example, a column
specified as *Note `SMALLINT(3)': numeric-types. has the usual *Note
`SMALLINT': numeric-types. range of `-32768' to `32767', and values
outside the range permitted by three digits are displayed in full using
more than three digits.

When used in conjunction with the optional (nonstandard) attribute
`ZEROFILL', the default padding of spaces is replaced with zeros. For
example, for a column declared as *Note `INT(4) ZEROFILL':
numeric-types, a value of `5' is retrieved as `0005'.

*Note*:

The `ZEROFILL' attribute is ignored when a column is involved in
expressions or *Note `UNION': union. queries.

If you store values larger than the display width in an integer column
that has the `ZEROFILL' attribute, you may experience problems when
MySQL generates temporary tables for some complicated joins. In these
cases, MySQL assumes that the data values fit within the column display
width.

All integer types can have an optional (nonstandard) attribute
`UNSIGNED'. Unsigned type can be used to permit only nonnegative
numbers in a column or when you need a larger upper numeric range for
the column. For example, if an *Note `INT': numeric-types. column is
`UNSIGNED', the size of the column's range is the same but its
endpoints shift from `-2147483648' and `2147483647' up to `0' and
`4294967295'.

Floating-point and fixed-point types also can be `UNSIGNED'. As with
integer types, this attribute prevents negative values from being
stored in the column. Unlike the integer types, the upper range of
column values remains the same.

If you specify `ZEROFILL' for a numeric column, MySQL automatically
adds the `UNSIGNED' attribute to the column.

Integer or floating-point data types can have the additional attribute
`AUTO_INCREMENT'. When you insert a value of `NULL' (recommended) or
`0' into an indexed `AUTO_INCREMENT' column, the column is set to the
next sequence value. Typically this is `VALUE+1', where VALUE is the
largest value for the column currently in the table. `AUTO_INCREMENT'
sequences begin with `1'.


File: manual.info,  Node: out-of-range-and-overflow,  Prev: numeric-type-attributes,  Up: numeric-types

11.2.6 Out-of-Range and Overflow Handling
-----------------------------------------

When MySQL stores a value in a numeric column that is outside the
permissible range of the column data type, the result depends on the
SQL mode in effect at the time:

   * If strict SQL mode is enabled, MySQL rejects the out-of-range
     value with an error, and the insert fails, in accordance with the
     SQL standard.

   * If no restrictive modes are enabled, MySQL clips the value to the
     appropriate endpoint of the range and stores the resulting value
     instead.

     When an out-of-range value is assigned to an integer column, MySQL
     stores the value representing the corresponding endpoint of the
     column data type range. If you store 256 into a *Note `TINYINT':
     numeric-types. or `TINYINT UNSIGNED' column, MySQL stores 127 or
     255, respectively.

     When a floating-point or fixed-point column is assigned a value
     that exceeds the range implied by the specified (or default)
     precision and scale, MySQL stores the value representing the
     corresponding endpoint of that range.

Column-assignment conversions that occur due to clipping when MySQL is
not operating in strict mode are reported as warnings for *Note `ALTER
TABLE': alter-table, *Note `LOAD DATA INFILE': load-data, *Note
`UPDATE': update, and multiple-row *Note `INSERT': insert. statements.
In strict mode, these statements fail, and some or all the values will
not be inserted or changed, depending on whether the table is a
transactional table and other factors. For details, see *Note
server-sql-mode::.

In MySQL 5.0, overflow handling during numeric expression evaluation
depends on the types of the operands:

   * Integer overflow results in silent wraparound.

   * `DECIMAL' overflow results in a truncated result and a warning.

   * Floating-point overflow produces a `NULL' result. Overflow for
     some operations can result in `+INF', `-INF', or `NaN'.

For example, the largest signed *Note `BIGINT': numeric-types. value is
9223372036854775807, so the following expression wraps around to the
minimum *Note `BIGINT': numeric-types. value:

     mysql> SELECT 9223372036854775807 + 1;
     +-------------------------+
     | 9223372036854775807 + 1 |
     +-------------------------+
     |    -9223372036854775808 |
     +-------------------------+

To enable the operation to succeed in this case, convert the value to
unsigned;

     mysql> SELECT CAST(9223372036854775807 AS UNSIGNED) + 1;
     +-------------------------------------------+
     | CAST(9223372036854775807 AS UNSIGNED) + 1 |
     +-------------------------------------------+
     |                       9223372036854775808 |
     +-------------------------------------------+

Whether overflow occurs depends on the range of the operands, so
another way to handle the preceding expression is to use exact-value
arithmetic because *Note `DECIMAL': numeric-types. values have a larger
range than integers:

     mysql> SELECT 9223372036854775807.0 + 1;
     +---------------------------+
     | 9223372036854775807.0 + 1 |
     +---------------------------+
     |     9223372036854775808.0 |
     +---------------------------+

Subtraction between integer values, where one is of type `UNSIGNED',
produces an unsigned result by default. If the result would otherwise
have been negative, it becomes the maximum integer value. If the
`NO_UNSIGNED_SUBTRACTION' SQL mode is enabled, the result is negative.

     mysql> SET sql_mode = '';
     mysql> SELECT CAST(0 AS UNSIGNED) - 1;
     +-------------------------+
     | CAST(0 AS UNSIGNED) - 1 |
     +-------------------------+
     |    18446744073709551615 |
     +-------------------------+

     mysql> SET sql_mode = 'NO_UNSIGNED_SUBTRACTION';
     mysql> SELECT CAST(0 AS UNSIGNED) - 1;
     +-------------------------+
     | CAST(0 AS UNSIGNED) - 1 |
     +-------------------------+
     |                      -1 |
     +-------------------------+

If the result of such an operation is used to update an `UNSIGNED'
integer column, the result is clipped to the maximum value for the
column type, or clipped to 0 if `NO_UNSIGNED_SUBTRACTION' is enabled.
If strict SQL mode is enabled, an error occurs and the column remains
unchanged.


File: manual.info,  Node: date-and-time-types,  Next: string-types,  Prev: numeric-types,  Up: data-types

11.3 Date and Time Types
========================

* Menu:

* datetime::                     The `DATE', `DATETIME', and `TIMESTAMP' Types
* time::                         The `TIME' Type
* year::                         The `YEAR' Type
* fractional-seconds::           Fractional Seconds in Time Values
* date-and-time-type-conversion::  Conversion Between Date and Time Types
* two-digit-years::              Two-Digit Years in Dates

The date and time types for representing temporal values are *Note
`DATE': datetime, *Note `TIME': time, *Note `DATETIME': datetime, *Note
`TIMESTAMP': datetime, and *Note `YEAR': year. Each temporal type has a
range of legal values, as well as a `zero' value that may be used when
you specify an illegal value that MySQL cannot represent. The *Note
`TIMESTAMP': datetime. type has special automatic updating behavior,
described later. For temporal type storage requirements, see *Note
storage-requirements::.

Keep in mind these general considerations when working with date and
time types:

   * MySQL retrieves values for a given date or time type in a standard
     output format, but it attempts to interpret a variety of formats
     for input values that you supply (for example, when you specify a
     value to be assigned to or compared to a date or time type). For a
     description of the permitted formats for date and time types, see
     *Note date-and-time-literals::. It is expected that you supply
     legal values. Unpredictable results may occur if you use values in
     other formats.

   * Although MySQL tries to interpret values in several formats, date
     parts must always be given in year-month-day order (for example,
     `'98-09-04''), rather than in the month-day-year or day-month-year
     orders commonly used elsewhere (for example, `'09-04-98'',
     `'04-09-98'').

   * Dates containing two-digit year values are ambiguous because the
     century is unknown. MySQL interprets two-digit year values using
     these rules:

        * Year values in the range `70-99' are converted to `1970-1999'.

        * Year values in the range `00-69' are converted to `2000-2069'.

     See also *Note two-digit-years::.

   * Conversion of values from one temporal type to another occurs
     according to the rules in *Note date-and-time-type-conversion::.

   * MySQL automatically converts a date or time value to a number if
     the value is used in a numeric context and vice versa.

   * By default, when MySQL encounters a value for a date or time type
     that is out of range or otherwise illegal for the type, it
     converts the value to the `zero' value for that type. The
     exception is that out-of-range *Note `TIME': time. values are
     clipped to the appropriate endpoint of the *Note `TIME': time.
     range.

   * Starting from MySQL 5.0.2, by setting the SQL mode to the
     appropriate value, you can specify more exactly what kind of dates
     you want MySQL to support. (See *Note server-sql-mode::.) You can
     get MySQL to accept certain dates, such as `'2009-11-31'', by
     enabling the `ALLOW_INVALID_DATES' SQL mode. (Before 5.0.2, this
     mode was the default behavior for MySQL.) This is useful when you
     want to store a `possibly wrong' value which the user has
     specified (for example, in a web form) in the database for future
     processing. Under this mode, MySQL verifies only that the month is
     in the range from 1 to 12 and that the day is in the range from 1
     to 31.

   * MySQL permits you to store dates where the day or month and day
     are zero in a *Note `DATE': datetime. or *Note `DATETIME':
     datetime. column. This is extremely useful for applications that
     need to store birthdates for which you may not know the exact
     date. In this case, you simply store the date as `'2009-00-00'' or
     `'2009-01-00''. If you store dates such as these, you should not
     expect to get correct results for functions such as `DATE_SUB()' or
     `DATE_ADD()' that require complete dates. To disallow zero month
     or day parts in dates, enable the `NO_ZERO_IN_DATE' SQL mode.

   * MySQL permits you to store a `zero' value of `'0000-00-00'' as a
     `dummy date.' This is in some cases more convenient than using
     `NULL' values, and uses less data and index space. To disallow
     `'0000-00-00'', enable the `NO_ZERO_DATE' SQL mode.

   * `Zero' date or time values used through Connector/ODBC are
     converted automatically to `NULL' because ODBC cannot handle such
     values.

The following table shows the format of the `zero' value for each type.
The `zero' values are special, but you can store or refer to them
explicitly using the values shown in the table. You can also do this
using the values `'0'' or `0', which are easier to write. Use of these
values produces warnings if the `NO_ZERO_DATE' SQL mode is enabled.

Data Type              `Zero' Value
*Note `DATE':          `'0000-00-00''
datetime.              
*Note `TIME': time.    `'00:00:00''
*Note `DATETIME':      `'0000-00-00 00:00:00''
datetime.              
*Note `TIMESTAMP':     `'0000-00-00 00:00:00''
datetime.              
*Note `YEAR': year.    `0000'


File: manual.info,  Node: datetime,  Next: time,  Prev: date-and-time-types,  Up: date-and-time-types

11.3.1 The `DATE', `DATETIME', and `TIMESTAMP' Types
----------------------------------------------------

* Menu:

* timestamp::                    `TIMESTAMP' Properties

The *Note `DATE': datetime, *Note `DATETIME': datetime, and *Note
`TIMESTAMP': datetime. types are related. This section describes their
characteristics, how they are similar, and how they differ.

The *Note `DATE': datetime. type is used for values with a date part
but no time part. MySQL retrieves and displays *Note `DATE': datetime.
values in `'YYYY-MM-DD'' format. The supported range is `'1000-01-01''
to `'9999-12-31''.

The *Note `DATETIME': datetime. type is used for values that contain
both date and time parts. MySQL retrieves and displays *Note
`DATETIME': datetime. values in `'YYYY-MM-DD HH:MM:SS'' format. The
supported range is `'1000-01-01 00:00:00'' to `'9999-12-31 23:59:59''.

For the *Note `DATE': datetime. and *Note `DATETIME': datetime. range
descriptions, `supported' means that although earlier values might
work, there is no guarantee.

The *Note `TIMESTAMP': datetime. data type is used for values that
contain both date and time parts.  *Note `TIMESTAMP': datetime. has a
range of `'1970-01-01 00:00:01'' UTC to `'2038-01-19 03:14:07'' UTC.
Its properties are described in more detail in *Note timestamp::.

MySQL recognizes *Note `DATE': datetime, *Note `DATETIME': datetime, and
*Note `TIMESTAMP': datetime. values in several formats, described in
*Note date-and-time-literals::.  A *Note `DATETIME': datetime. or *Note
`TIMESTAMP': datetime. value can include a trailing fractional seconds
part in up to microseconds (6 digits) precision. Although this
fractional part is recognized, it is discarded from values stored into
*Note `DATETIME': datetime. or *Note `TIMESTAMP': datetime. columns. For
information about fractional seconds support in MySQL, see *Note
fractional-seconds::.

Illegal *Note `DATE': datetime, *Note `DATETIME': datetime, or *Note
`TIMESTAMP': datetime. values are converted to the `zero' value of the
appropriate type (`'0000-00-00'' or `'0000-00-00 00:00:00'').

Be aware of certain problems when specifying date values:

   * MySQL permits a `relaxed' format for values specified as strings,
     in which any punctuation character may be used as the delimiter
     between date parts or time parts.  In some cases, this syntax can
     be deceiving. For example, a value such as `'10:11:12'' might look
     like a time value because of the ``:'' delimiter, but is
     interpreted as the year `'2010-11-12'' if used in a date context.
     The value `'10:45:15'' is converted to `'0000-00-00'' because
     `'45'' is not a legal month.

   * As of 5.0.2, the server requires that month and day values be
     legal, and not merely in the range 1 to 12 and 1 to 31,
     respectively. With strict mode disabled, invalid dates such as
     `'2004-04-31'' are converted to `'0000-00-00'' and a warning is
     generated.  With strict mode enabled, invalid dates generate an
     error.  To permit such dates, enable `ALLOW_INVALID_DATES'. See
     *Note server-sql-mode::, for more information.

     Before MySQL 5.0.2, the MySQL server performs only basic checking
     on the validity of a date: The ranges for year, month, and day are
     1000 to 9999, 00 to 12, and 00 to 31, respectively. Any date
     containing parts not within these ranges is subject to conversion
     to `'0000-00-00''. Please note that this still permits you to
     store invalid dates such as `'2002-04-31''. To ensure that a date
     is valid, you should perform a check in your application.

   * As of MySQL 5.0.2, MySQL does not accept *Note `TIMESTAMP':
     datetime. values that include a zero in the day or month column or
     values that are not a valid date. The sole exception to this rule
     is the special `zero' value `'0000-00-00 00:00:00''.

   * Dates containing two-digit year values are ambiguous because the
     century is unknown. MySQL interprets two-digit year values using
     these rules:

        * Year values in the range `00-69' are converted to `2000-2069'.

        * Year values in the range `70-99' are converted to `1970-1999'.

     See also *Note two-digit-years::.


File: manual.info,  Node: timestamp,  Prev: datetime,  Up: datetime

11.3.1.1 `TIMESTAMP' Properties
...............................

*Note `TIMESTAMP': datetime. columns are displayed using the same
format as *Note `DATETIME': datetime. columns, `'YYYY-MM-DD HH:MM:SS''.

*Note*:

In older versions of MySQL (prior to 4.1), the properties of the *Note
`TIMESTAMP': datetime. data type differed significantly in several ways
from what is described in this section (see the `MySQL 3.23, 4.0, 4.1
Reference Manual' for details); these include syntax extensions which
are deprecated in MySQL 5.1, and no longer supported in MySQL 5.5. This
has implications for performing a dump and restore or replicating
between MySQL Server versions. If you are using columns that are
defined using the old *Note `TIMESTAMP(N)': datetime. syntax, see *Note
upgrading-from-previous-series::, prior to upgrading to MySQL 5.1 or
later.

*Note `TIMESTAMP': datetime. values are converted from the current time
zone to UTC for storage, and converted back from UTC to the current
time zone for retrieval. (This does not occur for other types such as
*Note `DATETIME': datetime.) By default, the current time zone for each
connection is the server's time.  The time zone can be set on a
per-connection basis. As long as the time zone setting remains
constant, you get back the same value you store. If you store a *Note
`TIMESTAMP': datetime. value, and then change the time zone and
retrieve the value, the retrieved value is different from the value you
stored. This occurs because the same time zone was not used for
conversion in both directions. The current time zone is available as
the value of the `time_zone' system variable. For more information, see
*Note time-zone-support::.

The *Note `TIMESTAMP': datetime. data type offers automatic
initialization and updating. You can choose whether to use these
properties and which column should have them:

   * For one *Note `TIMESTAMP': datetime. column in a table, you can
     assign the current timestamp as the default value and the
     auto-update value. The current timestamp can be the default value
     for initializing the column, for the auto-update value, or both.
     However, it is not possible to have the current timestamp be the
     default value for one column and the auto-update value for another
     column.

   * Any *Note `TIMESTAMP': datetime. column in a table can be used as
     the one that is initialized to the current date and time, or
     updated automatically. This need not be the first *Note
     `TIMESTAMP': datetime.  column.

   * The auto-update *Note `TIMESTAMP': datetime.  column, if there is
     one, is automatically updated to the current timestamp when the
     value of any other column in the row is changed from its current
     value. If all other columns are set to their current values, the
     *Note `TIMESTAMP': datetime. column does not change. Automatic
     updating does not apply if the *Note `TIMESTAMP': datetime. column
     is explicitly assigned a value other than `NULL'.

   * If a `DEFAULT' value is specified for the first *Note `TIMESTAMP':
     datetime. column in a table, it is not ignored. The default can be
     `CURRENT_TIMESTAMP' or a constant date and time value.

   * In a *Note `CREATE TABLE': create-table.  statement, the first
     *Note `TIMESTAMP': datetime. column can be declared in any of the
     following ways:

        * With both `DEFAULT CURRENT_TIMESTAMP' and `ON UPDATE
          CURRENT_TIMESTAMP' clauses, the column has the current
          timestamp for its default value, and is automatically updated.

        * With neither `DEFAULT' nor `ON UPDATE' clauses, it is the same
          as `DEFAULT CURRENT_TIMESTAMP ON UPDATE CURRENT_TIMESTAMP'.

        * With a `DEFAULT CURRENT_TIMESTAMP' clause and no `ON UPDATE'
          clause, the column has the current timestamp for its default
          value but is not automatically updated.

        * With no `DEFAULT' clause and with an `ON UPDATE
          CURRENT_TIMESTAMP' clause, the column has a default of 0 and
          is automatically updated.

        * With a constant `DEFAULT' value, the column has the given
          default and is not automatically initialized to the current
          timestamp. If the column also has an `ON UPDATE
          CURRENT_TIMESTAMP' clause, it is automatically updated;
          otherwise, it has a constant default and is not automatically
          updated.

     In other words, you can use the current timestamp for both the
     initial value and the auto-update value, or either one, or
     neither. (For example, you can specify `ON UPDATE' to enable
     auto-update without also having the column auto-initialized.) The
     following column definitions demonstrate each possibility:

        * Auto-initialization and auto-update:

               COL_NAME TIMESTAMP DEFAULT CURRENT_TIMESTAMP ON UPDATE CURRENT_TIMESTAMP

        * Auto-initialization only:

               COL_NAME TIMESTAMP DEFAULT CURRENT_TIMESTAMP

        * Auto-update only:

               COL_NAME TIMESTAMP DEFAULT 0 ON UPDATE CURRENT_TIMESTAMP

        * Neither:

               COL_NAME TIMESTAMP DEFAULT 0

   * To specify automatic default or updating for a *Note `TIMESTAMP':
     datetime. column other than the first one, you must suppress the
     automatic initialization and update behaviors for the first *Note
     `TIMESTAMP': datetime. column by explicitly assigning it a constant
     `DEFAULT' value (for example, `DEFAULT 0' or `DEFAULT '2003-01-01
     00:00:00''). Then, for the other *Note `TIMESTAMP': datetime.
     column, the rules are the same as for the first *Note `TIMESTAMP':
     datetime. column, except that if you omit both of the `DEFAULT'
     and `ON UPDATE' clauses, no automatic initialization or updating
     occurs.

     Example:

          CREATE TABLE t (
              ts1 TIMESTAMP DEFAULT 0,
              ts2 TIMESTAMP DEFAULT CURRENT_TIMESTAMP
                            ON UPDATE CURRENT_TIMESTAMP);

   * `CURRENT_TIMESTAMP' or any of its synonyms (`CURRENT_TIMESTAMP()',
     `NOW()', `LOCALTIME', `LOCALTIME()', `LOCALTIMESTAMP', or
     `LOCALTIMESTAMP()') can be used in the `DEFAULT' and `ON UPDATE'
     clauses. They all mean `the current timestamp.' `UTC_TIMESTAMP' is
     not permitted. Its range of values does not align with those of
     the *Note `TIMESTAMP': datetime. column except when the current
     time zone is `UTC'.

   * The order of the `DEFAULT' and `ON UPDATE' clauses does not
     matter. If both `DEFAULT' and `ON UPDATE' are specified for a
     *Note `TIMESTAMP': datetime. column, either can precede the other.
     For example, these statements are equivalent:

          CREATE TABLE t (ts TIMESTAMP);
          CREATE TABLE t (ts TIMESTAMP DEFAULT CURRENT_TIMESTAMP
                                       ON UPDATE CURRENT_TIMESTAMP);
          CREATE TABLE t (ts TIMESTAMP ON UPDATE CURRENT_TIMESTAMP
                                       DEFAULT CURRENT_TIMESTAMP);

*Note*:

The examples that use `DEFAULT 0' will not work if the `NO_ZERO_DATE'
SQL mode is enabled because that mode causes `zero' date values
(specified as `0', `'0000-00-00', or `'0000-00-00 00:00:00'') to be
rejected. Be aware that the `TRADITIONAL' SQL mode includes
`NO_ZERO_DATE'.

*Note `TIMESTAMP': datetime. columns are `NOT NULL' by default, cannot
contain `NULL' values, and assigning `NULL' assigns the current
timestamp.  However, a *Note `TIMESTAMP': datetime. column can be
permitted to contain `NULL' by declaring it with the `NULL' attribute.
In this case, the default value also becomes `NULL' unless overridden
with a `DEFAULT' clause that specifies a different default value.
`DEFAULT NULL' can be used to explicitly specify `NULL' as the default
value. (For a *Note `TIMESTAMP': datetime. column not declared with the
`NULL' attribute, `DEFAULT NULL' is illegal.) If a *Note `TIMESTAMP':
datetime. column permits `NULL' values, assigning `NULL' sets it to
`NULL', not to the current timestamp.

The following table contains several *Note `TIMESTAMP': datetime.
columns that permit `NULL' values:

     CREATE TABLE t
     (
       ts1 TIMESTAMP NULL DEFAULT NULL,
       ts2 TIMESTAMP NULL DEFAULT 0,
       ts3 TIMESTAMP NULL DEFAULT CURRENT_TIMESTAMP
     );

Note that a *Note `TIMESTAMP': datetime. column that permits `NULL'
values will _not_ take on the current timestamp except under one of the
following conditions:

   * Its default value is defined as `CURRENT_TIMESTAMP'

   * `NOW()' or `CURRENT_TIMESTAMP' is inserted into the column

In other words, a *Note `TIMESTAMP': datetime.  column defined as
`NULL' will auto-initialize only if it is created using a definition
such as the following:

     CREATE TABLE t (ts TIMESTAMP NULL DEFAULT CURRENT_TIMESTAMP);

Otherwise--that is, if the *Note `TIMESTAMP': datetime. column is
defined to permit `NULL' values but not using `DEFAULT
CURRENT_TIMESTAMP', as shown here...

     CREATE TABLE t1 (ts TIMESTAMP NULL DEFAULT NULL);
     CREATE TABLE t2 (ts TIMESTAMP NULL DEFAULT '0000-00-00 00:00:00');

...then you must explicitly insert a value corresponding to the current
date and time. For example:

     INSERT INTO t1 VALUES (NOW());
     INSERT INTO t2 VALUES (CURRENT_TIMESTAMP);

*Note*:

The MySQL server can be run with the `MAXDB' SQL mode enabled. In this
case, *Note `TIMESTAMP': datetime. is identical with *Note `DATETIME':
datetime. If this mode is enabled at the time that a table is created,
*Note `TIMESTAMP': datetime. columns are created as *Note `DATETIME':
datetime. columns. As a result, such columns use *Note `DATETIME':
datetime. display format, have the same range of values, and there is
no automatic initialization or updating to the current date and time.
See *Note server-sql-mode::.


File: manual.info,  Node: time,  Next: year,  Prev: datetime,  Up: date-and-time-types

11.3.2 The `TIME' Type
----------------------

MySQL retrieves and displays *Note `TIME': time.  values in
`'HH:MM:SS'' format (or `'HHH:MM:SS'' format for large hours values).
*Note `TIME': time. values may range from `'-838:59:59'' to
`'838:59:59''. The hours part may be so large because the *Note `TIME':
time. type can be used not only to represent a time of day (which must
be less than 24 hours), but also elapsed time or a time interval
between two events (which may be much greater than 24 hours, or even
negative).

MySQL recognizes *Note `TIME': time. values in several formats,
described in *Note date-and-time-literals::. Some of these formats can
include a trailing fractional seconds part in up to microseconds (6
digits) precision. Although this fractional part is recognized, it is
discarded from values stored into *Note `TIME': time. columns. For
information about fractional seconds support in MySQL, see *Note
fractional-seconds::.

Be careful about assigning abbreviated values to a *Note `TIME': time.
column. MySQL interprets abbreviated *Note `TIME': time. values with
colons as time of the day. That is, `'11:12'' means `'11:12:00'', not
`'00:11:12''. MySQL interprets abbreviated values without colons using
the assumption that the two rightmost digits represent seconds (that
is, as elapsed time rather than as time of day). For example, you might
think of `'1112'' and `1112' as meaning `'11:12:00'' (12 minutes after
11 o'clock), but MySQL interprets them as `'00:11:12'' (11 minutes, 12
seconds). Similarly, `'12'' and `12' are interpreted as `'00:00:12''.

By default, values that lie outside the *Note `TIME': time. range but
are otherwise legal are clipped to the closest endpoint of the range.
For example, `'-850:00:00'' and `'850:00:00'' are converted to
`'-838:59:59'' and `'838:59:59''. Illegal *Note `TIME': time. values
are converted to `'00:00:00''. Note that because `'00:00:00'' is itself
a legal *Note `TIME': time. value, there is no way to tell, from a
value of `'00:00:00'' stored in a table, whether the original value was
specified as `'00:00:00'' or whether it was illegal.

For more restrictive treatment of invalid *Note `TIME': time. values,
enable strict SQL mode to cause errors to occur. See *Note
server-sql-mode::.


File: manual.info,  Node: year,  Next: fractional-seconds,  Prev: time,  Up: date-and-time-types

11.3.3 The `YEAR' Type
----------------------

The *Note `YEAR': year. type is a one-byte type used for representing
years. It can be declared as `YEAR(2)' or `YEAR(4)' to specify a
display width of two or four characters. The default is four characters
if no width is given.

For four-digit format, MySQL displays *Note `YEAR': year. values in
`YYYY' format, with a range of `1901' to `2155', or `0000'. For
two-digit format, MySQL displays only the last two (least significant)
digits; for example, `70' (1970 or 2070) or `69' (2069).

You can specify input *Note `YEAR': year. values in a variety of
formats:

   * As a four-digit string in the range `'1901'' to `'2155''.

   * As a four-digit number in the range `1901' to `2155'.

   * As a two-digit string in the range `'00'' to `'99''. Values in the
     ranges `'00'' to `'69'' and `'70'' to `'99'' are converted to
     *Note `YEAR': year. values in the ranges `2000' to `2069' and
     `1970' to `1999'.

   * As a two-digit number in the range `1' to `99'. Values in the
     ranges `1' to `69' and `70' to `99' are converted to *Note `YEAR':
     year. values in the ranges `2001' to `2069' and `1970' to `1999'.
     Note that the range for two-digit numbers is slightly different
     from the range for two-digit strings, because you cannot specify
     zero directly as a number and have it be interpreted as `2000'.
     You must specify it as a string `'0'' or `'00'' or it is
     interpreted as `0000'.

   * As the result of a function that returns a value that is
     acceptable in a *Note `YEAR': year. context, such as `NOW()'.

Illegal *Note `YEAR': year. values are converted to `0000'.

See also *Note two-digit-years::.


File: manual.info,  Node: fractional-seconds,  Next: date-and-time-type-conversion,  Prev: year,  Up: date-and-time-types

11.3.4 Fractional Seconds in Time Values
----------------------------------------

A trailing fractional seconds part is permissible for temporal values
in contexts such as literal values, and in the arguments to or return
values from some temporal functions. Example:

     mysql> SELECT MICROSECOND('2010-12-10 14:12:09.019473');
     +-------------------------------------------+
     | MICROSECOND('2010-12-10 14:12:09.019473') |
     +-------------------------------------------+
     |                                     19473 |
     +-------------------------------------------+

However, when MySQL stores a value into a column of any temporal data
type, it discards any fractional part and does not store it.


File: manual.info,  Node: date-and-time-type-conversion,  Next: two-digit-years,  Prev: fractional-seconds,  Up: date-and-time-types

11.3.5 Conversion Between Date and Time Types
---------------------------------------------

To some extent, you can convert a value from one temporal type to
another. However, there may be some alteration of the value or loss of
information. In all cases, conversion between temporal types is subject
to the range of legal values for the resulting type. For example,
although *Note `DATE': datetime, *Note `DATETIME': datetime, and *Note
`TIMESTAMP': datetime. values all can be specified using the same set
of formats, the types do not all have the same range of values.  *Note
`TIMESTAMP': datetime. values cannot be earlier than `1970' UTC or
later than `'2038-01-19 03:14:07'' UTC. This means that a date such as
`'1968-01-01'', while legal as a *Note `DATE': datetime. or *Note
`DATETIME': datetime. value, is not valid as a *Note `TIMESTAMP':
datetime. value and is converted to `0'.

Conversion of *Note `DATE': datetime. values:

   * Conversion to a *Note `DATETIME': datetime. or *Note `TIMESTAMP':
     datetime. value adds a time part of `'00:00:00'' because the *Note
     `DATE': datetime. value contains no time information.

   * Conversion to a *Note `TIME': time. value is not useful; the
     result is `'00:00:00''.

Conversion of *Note `DATETIME': datetime. and *Note `TIMESTAMP':
datetime. values:

   * Conversion to a *Note `DATE': datetime. value discards the time
     part because the *Note `DATE': datetime. type contains no time
     information.

   * Conversion to a *Note `TIME': time. value discards the date part
     because the *Note `TIME': time. type contains no date information.

Conversion of *Note `TIME': time. values:

MySQL converts a time value to a date or date-and-time value by parsing
the string value of the time as a date or date-and-time.  This is
unlikely to be useful. For example, `'23:12:31'' interpreted as a date
becomes `'2032-12-31''. Time values not valid as dates become
`'0000-00-00'' or `NULL'.

Prior to MySQL 5.0.42, when *Note `DATE': datetime.  values are
compared with *Note `DATETIME': datetime.  values, the time portion of
the *Note `DATETIME': datetime. value is ignored, or the comparison
could be performed as a string compare. Starting from MySQL 5.0.42, a
*Note `DATE': datetime. value is coerced to the *Note `DATETIME':
datetime. type by adding the time portion as `'00:00:00''. To mimic the
old behavior, use the `CAST()' function to cause the comparison
operands to be treated as previously. For example:

     DATE_COL = CAST(DATETIME_COL AS DATE)

As of MySQL 5.0.8, conversion of *Note `TIME': time. or *Note
`DATETIME': datetime. values to numeric form (for example, by adding
`+0') results in a double-precision value with a microseconds part of
`.000000':

     mysql> SELECT CURTIME(), CURTIME()+0;
     +-----------+---------------+
     | CURTIME() | CURTIME()+0   |
     +-----------+---------------+
     | 10:41:36  | 104136.000000 |
     +-----------+---------------+
     mysql> SELECT NOW(), NOW()+0;
     +---------------------+-----------------------+
     | NOW()               | NOW()+0               |
     +---------------------+-----------------------+
     | 2007-11-30 10:41:47 | 20071130104147.000000 |
     +---------------------+-----------------------+

Before MySQL 5.0.8, the conversion results in an integer value with no
microseconds part.


File: manual.info,  Node: two-digit-years,  Prev: date-and-time-type-conversion,  Up: date-and-time-types

11.3.6 Two-Digit Years in Dates
-------------------------------

Date values with two-digit years are ambiguous because the century is
unknown. Such values must be interpreted into four-digit form because
MySQL stores years internally using four digits.

For *Note `DATETIME': datetime, *Note `DATE': datetime, *Note
`TIMESTAMP': datetime, and *Note `YEAR': year. types, MySQL interprets
dates specified with ambiguous year values using these rules:

   * Year values in the range `00-69' are converted to `2000-2069'.

   * Year values in the range `70-99' are converted to `1970-1999'.

Remember that these rules are only heuristics that provide reasonable
guesses as to what your data values mean. If the rules used by MySQL do
not produce the values you require, you must provide unambiguous input
containing four-digit year values.

In MySQL, the *Note `YEAR': year. data type can store the years `0' and
`1901' to `2155' in one byte and display them using two or four digits.
All two-digit years are considered to be in the range `1970' to `2069',
which means that if you store `01' in a *Note `YEAR': year. column,
MySQL Server treats it as `2001'.

`ORDER BY' properly sorts *Note `YEAR': year. values that have two-digit
years.

Some functions like `MIN()' and `MAX()' convert a *Note `YEAR': year.
to a number. This means that a value with a two-digit year does not
work properly with these functions. The fix in this case is to convert
the *Note `YEAR': year. to four-digit year format.


File: manual.info,  Node: string-types,  Next: storage-requirements,  Prev: date-and-time-types,  Up: data-types

11.4 String Types
=================

* Menu:

* char::                         The `CHAR' and `VARCHAR' Types
* binary-varbinary::             The `BINARY' and `VARBINARY' Types
* blob::                         The `BLOB' and `TEXT' Types
* enum::                         The `ENUM' Type
* set::                          The `SET' Type

The string types are *Note `CHAR': char, *Note `VARCHAR': char, *Note
`BINARY': binary-varbinary, *Note `VARBINARY': binary-varbinary, *Note
`BLOB': blob, *Note `TEXT': blob, *Note `ENUM': enum, and *Note `SET':
set. This section describes how these types work and how to use them in
your queries. For string type storage requirements, see *Note
storage-requirements::.


File: manual.info,  Node: char,  Next: binary-varbinary,  Prev: string-types,  Up: string-types

11.4.1 The `CHAR' and `VARCHAR' Types
-------------------------------------

The *Note `CHAR': char. and *Note `VARCHAR': char. types are similar,
but differ in the way they are stored and retrieved. As of MySQL 5.0.3,
they also differ in maximum length and in whether trailing spaces are
retained.

The *Note `CHAR': char. and *Note `VARCHAR': char. types are declared
with a length that indicates the maximum number of characters you want
to store. For example, `CHAR(30)' can hold up to 30 characters.

The length of a *Note `CHAR': char. column is fixed to the length that
you declare when you create the table.  The length can be any value
from 0 to 255. When *Note `CHAR': char. values are stored, they are
right-padded with spaces to the specified length. When *Note `CHAR':
char. values are retrieved, trailing spaces are removed.

Values in *Note `VARCHAR': char. columns are variable-length strings.
The length can be specified as a value from 0 to 255 before MySQL
5.0.3, and 0 to 65,535 in 5.0.3 and later versions. The effective
maximum length of a *Note `VARCHAR': char. in MySQL 5.0.3 and later is
subject to the maximum row size (65,535 bytes, which is shared among
all columns) and the character set used. See *Note column-count-limit::.

In contrast to *Note `CHAR': char, *Note `VARCHAR': char. values are
stored as a one-byte or two-byte length prefix plus data. The length
prefix indicates the number of bytes in the value. A column uses one
length byte if values require no more than 255 bytes, two length bytes
if values may require more than 255 bytes.

If strict SQL mode is not enabled and you assign a value to a *Note
`CHAR': char. or *Note `VARCHAR': char. column that exceeds the
column's maximum length, the value is truncated to fit and a warning is
generated. For truncation of nonspace characters, you can cause an
error to occur (rather than a warning) and suppress insertion of the
value by using strict SQL mode. See *Note server-sql-mode::.

For *Note `VARCHAR': char. columns, trailing spaces in excess of the
column length are truncated prior to insertion and a warning is
generated, regardless of the SQL mode in use. For *Note `CHAR': char.
columns, truncation of excess trailing spaces from inserted values is
performed silently regardless of the SQL mode.

*Note `VARCHAR': char. values are not padded when they are stored.
Handling of trailing spaces is version-dependent. As of MySQL 5.0.3,
trailing spaces are retained when values are stored and retrieved, in
conformance with standard SQL. Before MySQL 5.0.3, trailing spaces are
removed from values when they are stored into a *Note `VARCHAR': char.
column; this means that the spaces also are absent from retrieved
values.

Before MySQL 5.0.3, if you need a data type for which trailing spaces
are not removed, consider using a *Note `BLOB': blob. or *Note `TEXT':
blob. type. Also, if you want to store binary values such as results
from an encryption or compression function that might contain arbitrary
byte values, use a *Note `BLOB': blob. column rather than a *Note
`CHAR': char. or *Note `VARCHAR': char. column, to avoid potential
problems with trailing space removal that would change data values.

The following table illustrates the differences between *Note `CHAR':
char. and *Note `VARCHAR': char. by showing the result of storing
various string values into `CHAR(4)' and `VARCHAR(4)' columns (assuming
that the column uses a single-byte character set such as `latin1').

Value       `CHAR(4)'   Storage        `VARCHAR(4)'Storage
                        Required                   Required
`'''        `'    ''    4 bytes        `'''        1 byte
`'ab''      `'ab  ''    4 bytes        `'ab''      3 bytes
`'abcd''    `'abcd''    4 bytes        `'abcd''    5 bytes
`'abcdefgh''`'abcd''    4 bytes        `'abcd''    5 bytes

The values shown as stored in the last row of the table apply _only
when not using strict mode_; if MySQL is running in strict mode, values
that exceed the column length are _not stored_, and an error results.

If a given value is stored into the `CHAR(4)' and `VARCHAR(4)' columns,
the values retrieved from the columns are not always the same because
trailing spaces are removed from *Note `CHAR': char. columns upon
retrieval. The following example illustrates this difference:

     mysql> CREATE TABLE vc (v VARCHAR(4), c CHAR(4));
     Query OK, 0 rows affected (0.01 sec)

     mysql> INSERT INTO vc VALUES ('ab  ', 'ab  ');
     Query OK, 1 row affected (0.00 sec)

     mysql> SELECT CONCAT('(', v, ')'), CONCAT('(', c, ')') FROM vc;
     +---------------------+---------------------+
     | CONCAT('(', v, ')') | CONCAT('(', c, ')') |
     +---------------------+---------------------+
     | (ab  )              | (ab)                |
     +---------------------+---------------------+
     1 row in set (0.06 sec)

Values in *Note `CHAR': char. and *Note `VARCHAR': char. columns are
sorted and compared according to the character set collation assigned to
the column.

All MySQL collations are of type `PADSPACE'.  This means that all *Note
`CHAR': char. and *Note `VARCHAR': char. values in MySQL are compared
without regard to any trailing spaces. For example:

     mysql> CREATE TABLE names (myname CHAR(10), yourname VARCHAR(10));
     Query OK, 0 rows affected (0.09 sec)

     mysql> INSERT INTO names VALUES ('Monty ', 'Monty ');
     Query OK, 1 row affected (0.00 sec)

     mysql> SELECT myname = 'Monty  ', yourname = 'Monty  ' FROM names;
     +--------------------+----------------------+
     | myname = 'Monty  ' | yourname = 'Monty  ' |
     +--------------------+----------------------+
     |                  1 |                    1 |
     +--------------------+----------------------+
     1 row in set (0.00 sec)

This is true for all MySQL versions, and it makes no difference whether
your version trims trailing spaces from *Note `VARCHAR': char. values
before storing them. Nor does the server SQL mode make any difference
in this regard.

*Note*:

For more information about MySQL character sets and collations, see
*Note charset::.

For those cases where trailing pad characters are stripped or
comparisons ignore them, if a column has an index that requires unique
values, inserting into the column values that differ only in number of
trailing pad characters will result in a duplicate-key error. For
example, if a table contains `'a'', an attempt to store `'a '' causes a
duplicate-key error.


File: manual.info,  Node: binary-varbinary,  Next: blob,  Prev: char,  Up: string-types

11.4.2 The `BINARY' and `VARBINARY' Types
-----------------------------------------

The *Note `BINARY': binary-varbinary. and *Note `VARBINARY':
binary-varbinary. types are similar to *Note `CHAR': char. and *Note
`VARCHAR': char, except that they contain binary strings rather than
nonbinary strings. That is, they contain byte strings rather than
character strings. This means that they have no character set, and
sorting and comparison are based on the numeric values of the bytes in
the values.

The permissible maximum length is the same for *Note `BINARY':
binary-varbinary. and *Note `VARBINARY': binary-varbinary. as it is for
*Note `CHAR': char. and *Note `VARCHAR': char, except that the length
for *Note `BINARY': binary-varbinary. and *Note `VARBINARY':
binary-varbinary. is a length in bytes rather than in characters.

The *Note `BINARY': binary-varbinary. and *Note `VARBINARY':
binary-varbinary. data types are distinct from the `CHAR BINARY' and
`VARCHAR BINARY' data types. For the latter types, the `BINARY'
attribute does not cause the column to be treated as a binary string
column. Instead, it causes the binary collation for the column
character set to be used, and the column itself contains nonbinary
character strings rather than binary byte strings. For example, `CHAR(5)
BINARY' is treated as `CHAR(5) CHARACTER SET latin1 COLLATE
latin1_bin', assuming that the default character set is `latin1'. This
differs from `BINARY(5)', which stores 5-bytes binary strings that have
no character set or collation. For information about differences
between nonbinary string binary collations and binary strings, see
*Note charset-binary-collations::.

If strict SQL mode is not enabled and you assign a value to a *Note
`BINARY': binary-varbinary. or *Note `VARBINARY': binary-varbinary.
column that exceeds the column's maximum length, the value is truncated
to fit and a warning is generated. For cases of truncation, you can
cause an error to occur (rather than a warning) and suppress insertion
of the value by using strict SQL mode. See *Note server-sql-mode::.

When *Note `BINARY': binary-varbinary. values are stored, they are
right-padded with the pad value to the specified length. The pad value
and how it is handled is version specific:

   * As of MySQL 5.0.15, the pad value is `0x00' (the zero byte).
     Values are right-padded with `0x00' on insert, and no trailing
     bytes are removed on select. All bytes are significant in
     comparisons, including `ORDER BY' and `DISTINCT' operations.
     `0x00' bytes and spaces are different in comparisons, with `0x00'
     < space.

     Example: For a `BINARY(3)' column, `'a '' becomes `'a \0'' when
     inserted.  `'a\0'' becomes `'a\0\0'' when inserted. Both inserted
     values remain unchanged when selected.

   * Before MySQL 5.0.15, the pad value is space. Values are
     right-padded with space on insert, and trailing spaces are removed
     on select. Trailing spaces are ignored in comparisons, including
     `ORDER BY' and `DISTINCT' operations.  `0x00' bytes and spaces are
     different in comparisons, with `0x00' < space.

     Example: For a `BINARY(3)' column, `'a '' becomes `'a  '' when
     inserted and `'a'' when selected.  `'a\0'' becomes `'a\0 '' when
     inserted and `'a\0'' when selected.

For *Note `VARBINARY': binary-varbinary, there is no padding on insert
and no bytes are stripped on select. All bytes are significant in
comparisons, including `ORDER BY' and `DISTINCT' operations.  `0x00'
bytes and spaces are different in comparisons, with `0x00' < space.
(Exceptions: Before MySQL 5.0.3, trailing spaces are removed when
values are stored. Before MySQL 5.0.15, trailing 0x00 bytes are removed
for `ORDER BY' operations.)

Note: The `InnoDB' storage engine continues to preserve trailing spaces
in *Note `BINARY': binary-varbinary. and *Note `VARBINARY':
binary-varbinary. column values through MySQL 5.0.18. Beginning with
MySQL 5.0.19, `InnoDB' uses trailing space characters in making
comparisons as do other MySQL storage engines.

For those cases where trailing pad bytes are stripped or comparisons
ignore them, if a column has an index that requires unique values,
inserting into the column values that differ only in number of trailing
pad bytes will result in a duplicate-key error. For example, if a table
contains `'a'', an attempt to store `'a\0'' causes a duplicate-key
error.

You should consider the preceding padding and stripping characteristics
carefully if you plan to use the *Note `BINARY': binary-varbinary. data
type for storing binary data and you require that the value retrieved
be exactly the same as the value stored. The following example
illustrates how `0x00'-padding of *Note `BINARY': binary-varbinary.
values affects column value comparisons:

     mysql> CREATE TABLE t (c BINARY(3));
     Query OK, 0 rows affected (0.01 sec)

     mysql> INSERT INTO t SET c = 'a';
     Query OK, 1 row affected (0.01 sec)

     mysql> SELECT HEX(c), c = 'a', c = 'a\0\0' from t;
     +--------+---------+-------------+
     | HEX(c) | c = 'a' | c = 'a\0\0' |
     +--------+---------+-------------+
     | 610000 |       0 |           1 |
     +--------+---------+-------------+
     1 row in set (0.09 sec)

If the value retrieved must be the same as the value specified for
storage with no padding, it might be preferable to use *Note
`VARBINARY': binary-varbinary. or one of the *Note `BLOB': blob. data
types instead.


File: manual.info,  Node: blob,  Next: enum,  Prev: binary-varbinary,  Up: string-types

11.4.3 The `BLOB' and `TEXT' Types
----------------------------------

A *Note `BLOB': blob. is a binary large object that can hold a variable
amount of data. The four *Note `BLOB': blob. types are *Note
`TINYBLOB': blob, *Note `BLOB': blob, *Note `MEDIUMBLOB': blob, and
*Note `LONGBLOB': blob. These differ only in the maximum length of the
values they can hold. The four *Note `TEXT': blob. types are *Note
`TINYTEXT': blob, *Note `TEXT': blob, *Note `MEDIUMTEXT': blob, and
*Note `LONGTEXT': blob. These correspond to the four *Note `BLOB':
blob. types and have the same maximum lengths and storage requirements.
See *Note storage-requirements::.

*Note `BLOB': blob. values are treated as binary strings (byte
strings). They have no character set, and sorting and comparison are
based on the numeric values of the bytes in column values. *Note
`TEXT': blob. values are treated as nonbinary strings (character
strings). They have a character set, and values are sorted and compared
based on the collation of the character set.

If strict SQL mode is not enabled and you assign a value to a *Note
`BLOB': blob. or *Note `TEXT': blob. column that exceeds the column's
maximum length, the value is truncated to fit and a warning is
generated. For truncation of nonspace characters, you can cause an
error to occur (rather than a warning) and suppress insertion of the
value by using strict SQL mode. See *Note server-sql-mode::.

Beginning with MySQL 5.0.60, truncation of excess trailing spaces from
values to be inserted into *Note `TEXT': blob. columns always generates
a warning, regardless of the SQL mode.

If a *Note `TEXT': blob. column is indexed, index entry comparisons are
space-padded at the end. This means that, if the index requires unique
values, duplicate-key errors will occur for values that differ only in
the number of trailing spaces. For example, if a table contains `'a'',
an attempt to store `'a '' causes a duplicate-key error. This is not
true for *Note `BLOB': blob. columns.

In most respects, you can regard a *Note `BLOB': blob. column as a
*Note `VARBINARY': binary-varbinary. column that can be as large as you
like. Similarly, you can regard a *Note `TEXT': blob. column as a *Note
`VARCHAR': char. column.  *Note `BLOB': blob. and *Note `TEXT': blob.
differ from *Note `VARBINARY': binary-varbinary. and *Note `VARCHAR':
char. in the following ways:

   * There is no trailing-space removal for *Note `BLOB': blob. and
     *Note `TEXT': blob. columns when values are stored or retrieved.
     Before MySQL 5.0.3, this differs from *Note `VARBINARY':
     binary-varbinary. and *Note `VARCHAR': char, for which trailing
     spaces are removed when values are stored.

     On comparisons, *Note `TEXT': blob. is space extended to fit the
     compared object, exactly like *Note `CHAR': char. and *Note
     `VARCHAR': char.

   * For indexes on *Note `BLOB': blob. and *Note `TEXT': blob.
     columns, you must specify an index prefix length. For *Note
     `CHAR': char. and *Note `VARCHAR': char, a prefix length is
     optional. See *Note column-indexes::.

   * *Note `BLOB': blob. and *Note `TEXT': blob. columns cannot have
     `DEFAULT' values.

If you use the `BINARY' attribute with a *Note `TEXT': blob. data type,
the column is assigned the binary collation of the column character set.

`LONG' and `LONG VARCHAR' map to the *Note `MEDIUMTEXT': blob. data
type. This is a compatibility feature.

MySQL Connector/ODBC defines *Note `BLOB': blob.  values as
`LONGVARBINARY' and *Note `TEXT': blob. values as `LONGVARCHAR'.

Because *Note `BLOB': blob. and *Note `TEXT': blob. values can be
extremely long, you might encounter some constraints in using them:

   * Only the first `max_sort_length' bytes of the column are used when
     sorting. The default value of `max_sort_length' is 1024.  You can
     make more bytes significant in sorting or grouping by increasing
     the value of `max_sort_length' at server startup or runtime. Any
     client can change the value of its session `max_sort_length'
     variable:

          mysql> SET max_sort_length = 2000;
          mysql> SELECT id, comment FROM t
              -> ORDER BY comment;

     Another way to use `GROUP BY' or `ORDER BY' on a *Note `BLOB':
     blob. or *Note `TEXT': blob. column containing long values when
     you want more than `max_sort_length' bytes to be significant is to
     convert the column value into a fixed-length object. The standard
     way to do this is with the `SUBSTRING()' function. For example,
     the following statement causes 2000 bytes of the `comment' column
     to be taken into account for sorting:

          mysql> SELECT id, SUBSTRING(comment,1,2000) FROM t
              -> ORDER BY SUBSTRING(comment,1,2000);

   * Instances of *Note `BLOB': blob. or *Note `TEXT': blob. columns in
     the result of a query that is processed using a temporary table
     causes the server to use a table on disk rather than in memory
     because the `MEMORY' storage engine does not support those data
     types (see *Note internal-temporary-tables::). Use of disk incurs
     a performance penalty, so include *Note `BLOB': blob. or *Note
     `TEXT': blob. columns in the query result only if they are really
     needed. For example, avoid using *Note `SELECT *': select, which
     selects all columns.

   * The maximum size of a *Note `BLOB': blob. or *Note `TEXT': blob.
     object is determined by its type, but the largest value you
     actually can transmit between the client and server is determined
     by the amount of available memory and the size of the
     communications buffers.  You can change the message buffer size by
     changing the value of the `max_allowed_packet' variable, but you
     must do so for both the server and your client program. For
     example, both *Note `mysql': mysql.  and *Note `mysqldump':
     mysqldump. enable you to change the client-side
     `max_allowed_packet' value.  See *Note server-parameters::, *Note
     mysql::, and *Note mysqldump::.  You may also want to compare the
     packet sizes and the size of the data objects you are storing with
     the storage requirements, see *Note storage-requirements::

Each *Note `BLOB': blob. or *Note `TEXT': blob. value is represented
internally by a separately allocated object. This is in contrast to all
other data types, for which storage is allocated once per column when
the table is opened.

In some cases, it may be desirable to store binary data such as media
files in *Note `BLOB': blob. or *Note `TEXT': blob. columns. You may
find MySQL's string handling functions useful for working with such
data. See *Note string-functions::. For security and other reasons, it
is usually preferable to do so using application code rather than
giving application users the `FILE' privilege. You can discuss
specifics for various languages and platforms in the MySQL Forums
(`http://forums.mysql.com/').


File: manual.info,  Node: enum,  Next: set,  Prev: blob,  Up: string-types

11.4.4 The `ENUM' Type
----------------------

An *Note `ENUM': enum. is a string object with a value chosen from a
list of permitted values that are enumerated explicitly in the column
specification at table creation time.

An enumeration value must be a quoted string literal; it may not be an
expression, even one that evaluates to a string value. For example, you
can create a table with an *Note `ENUM': enum. column like this:

     CREATE TABLE sizes (
         name ENUM('small', 'medium', 'large')
     );

However, this version of the previous *Note `CREATE TABLE':
create-table. statement does _not_ work:

     CREATE TABLE sizes (
         c1 ENUM('small', CONCAT('med','ium'), 'large')
     );

You also may not employ a user variable as an enumeration value.  This
pair of statements do _not_ work:

     SET @mysize = 'medium';

     CREATE TABLE sizes (
         name ENUM('small', @mysize, 'large')
     );

If you wish to use a number as an enumeration value, you must enclose
it in quotation marks. If the quotation marks are omitted, the number
is regarded as an index. For this and other reasons--as explained later
in this section--we strongly recommend that you do _not_ use numbers as
enumeration values.

Duplicate values in the definition cause a warning, or an error if
strict SQL mode is enabled.

The value may also be the empty string (`''') or `NULL' under certain
circumstances:

   * If you insert an invalid value into an *Note `ENUM': enum. (that
     is, a string not present in the list of permitted values), the
     empty string is inserted instead as a special error value. This
     string can be distinguished from a `normal' empty string by the
     fact that this string has the numeric value 0.  More about this
     later.

     If strict SQL mode is enabled, attempts to insert invalid *Note
     `ENUM': enum. values result in an error.

   * If an *Note `ENUM': enum. column is declared to permit `NULL', the
     `NULL' value is a legal value for the column, and the default
     value is `NULL'. If an *Note `ENUM': enum. column is declared `NOT
     NULL', its default value is the first element of the list of
     permitted values.

Each enumeration value has an index:

   * Values from the list of permissible elements in the column
     specification are numbered beginning with 1.

   * The index value of the empty string error value is 0. This means
     that you can use the following *Note `SELECT': select. statement
     to find rows into which invalid *Note `ENUM': enum.  values were
     assigned:

          mysql> SELECT * FROM TBL_NAME WHERE ENUM_COL=0;

   * The index of the `NULL' value is `NULL'.

   * The term `index' here refers only to position within the list of
     enumeration values. It has nothing to do with table indexes.

For example, a column specified as `ENUM('one', 'two', 'three')' can
have any of the values shown here. The index of each value is also
shown.

Value       Index
`NULL'      `NULL'
`'''        0
`'one''     1
`'two''     2
`'three''   3

An enumeration can have a maximum of 65,535 elements.

Trailing spaces are automatically deleted from *Note `ENUM': enum.
member values in the table definition when a table is created.

When retrieved, values stored into an *Note `ENUM': enum. column are
displayed using the lettercase that was used in the column definition.
Note that *Note `ENUM': enum. columns can be assigned a character set
and collation. For binary or case-sensitive collations, lettercase is
taken into account when assigning values to the column.

If you retrieve an *Note `ENUM': enum. value in a numeric context, the
column value's index is returned. For example, you can retrieve numeric
values from an *Note `ENUM': enum. column like this:

     mysql> SELECT ENUM_COL+0 FROM TBL_NAME;

If you store a number into an *Note `ENUM': enum. column, the number is
treated as the index into the possible values, and the value stored is
the enumeration member with that index. (However, this does _not_ work
with *Note `LOAD DATA': load-data, which treats all input as strings.)
If the numeric value is quoted, it is still interpreted as an index if
there is no matching string in the list of enumeration values. For
these reasons, it is not advisable to define an *Note `ENUM': enum.
column with enumeration values that look like numbers, because this can
easily become confusing. For example, the following column has
enumeration members with string values of `'0'', `'1'', and `'2'', but
numeric index values of `1', `2', and `3':

     numbers ENUM('0','1','2')

If you store `2', it is interpreted as an index value, and becomes
`'1'' (the value with index 2). If you store `'2'', it matches an
enumeration value, so it is stored as `'2''. If you store `'3'', it
does not match any enumeration value, so it is treated as an index and
becomes `'2'' (the value with index 3).

     mysql> INSERT INTO t (numbers) VALUES(2),('2'),('3');
     mysql> SELECT * FROM t;
     +---------+
     | numbers |
     +---------+
     | 1       |
     | 2       |
     | 2       |
     +---------+

*Note `ENUM': enum. values are sorted according to the order in which
the enumeration members were listed in the column specification. (In
other words, *Note `ENUM': enum. values are sorted according to their
index numbers.) For example, `'a'' sorts before `'b'' for `ENUM('a',
'b')', but `'b'' sorts before `'a'' for `ENUM('b', 'a')'.  The empty
string sorts before nonempty strings, and `NULL' values sort before all
other enumeration values. To prevent unexpected results, specify the
*Note `ENUM': enum. list in alphabetic order.  You can also use `ORDER
BY CAST(COL AS CHAR)' or `ORDER BY CONCAT(COL)' to make sure that the
column is sorted lexically rather than by index number.

Functions such as `SUM()' or `AVG()' that expect a numeric argument
cast the argument to a number if necessary. For *Note `ENUM': enum.
values, the cast operation causes the index number to be used.

To determine all possible values for an *Note `ENUM': enum. column, use
*Note `SHOW COLUMNS FROM TBL_NAME LIKE 'ENUM_COL'': show-columns. and
parse the *Note `ENUM': enum. definition in the `Type' column of the
output.

In the C API, *Note `ENUM': enum. values are returned as strings. For
information about using result set metadata to distinguish them from
other strings, see *Note c-api-data-structures::.


File: manual.info,  Node: set,  Prev: enum,  Up: string-types

11.4.5 The `SET' Type
---------------------

A *Note `SET': set. is a string object that can have zero or more
values, each of which must be chosen from a list of permitted values
specified when the table is created.  *Note `SET': set. column values
that consist of multiple set members are specified with members
separated by commas (``,''). A consequence of this is that *Note `SET':
set. member values should not themselves contain commas.

For example, a column specified as `SET('one', 'two') NOT NULL' can
have any of these values:

     ''
     'one'
     'two'
     'one,two'

A *Note `SET': set. can have a maximum of 64 different members.

Duplicate values in the definition cause a warning, or an error if
strict SQL mode is enabled.

Trailing spaces are automatically deleted from *Note `SET': set. member
values in the table definition when a table is created.

When retrieved, values stored in a *Note `SET': set. column are
displayed using the lettercase that was used in the column definition.
Note that *Note `SET': set. columns can be assigned a character set and
collation. For binary or case-sensitive collations, lettercase is taken
into account when assigning values to the column.

MySQL stores *Note `SET': set. values numerically, with the low-order
bit of the stored value corresponding to the first set member. If you
retrieve a *Note `SET': set. value in a numeric context, the value
retrieved has bits set corresponding to the set members that make up
the column value. For example, you can retrieve numeric values from a
*Note `SET': set. column like this:

     mysql> SELECT SET_COL+0 FROM TBL_NAME;

If a number is stored into a *Note `SET': set.  column, the bits that
are set in the binary representation of the number determine the set
members in the column value. For a column specified as
`SET('a','b','c','d')', the members have the following decimal and
binary values.

*Note       Decimal Value  Binary Value
`SET':                     
set. Member                
`'a''       `1'            `0001'
`'b''       `2'            `0010'
`'c''       `4'            `0100'
`'d''       `8'            `1000'

If you assign a value of `9' to this column, that is `1001' in binary,
so the first and fourth *Note `SET': set. value members `'a'' and `'d''
are selected and the resulting value is `'a,d''.

For a value containing more than one *Note `SET': set. element, it does
not matter what order the elements are listed in when you insert the
value.  It also does not matter how many times a given element is listed
in the value. When the value is retrieved later, each element in the
value appears once, with elements listed according to the order in
which they were specified at table creation time. For example, suppose
that a column is specified as `SET('a','b','c','d')':

     mysql> CREATE TABLE myset (col SET('a', 'b', 'c', 'd'));

If you insert the values `'a,d'', `'d,a'', `'a,d,d'', `'a,d,a'', and
`'d,a,d'':

     mysql> INSERT INTO myset (col) VALUES
     -> ('a,d'), ('d,a'), ('a,d,a'), ('a,d,d'), ('d,a,d');
     Query OK, 5 rows affected (0.01 sec)
     Records: 5  Duplicates: 0  Warnings: 0

Then all these values appear as `'a,d'' when retrieved:

     mysql> SELECT col FROM myset;
     +------+
     | col  |
     +------+
     | a,d  |
     | a,d  |
     | a,d  |
     | a,d  |
     | a,d  |
     +------+
     5 rows in set (0.04 sec)

If you set a *Note `SET': set. column to an unsupported value, the
value is ignored and a warning is issued:

     mysql> INSERT INTO myset (col) VALUES ('a,d,d,s');
     Query OK, 1 row affected, 1 warning (0.03 sec)

     mysql> SHOW WARNINGS;
     +---------+------+------------------------------------------+
     | Level   | Code | Message                                  |
     +---------+------+------------------------------------------+
     | Warning | 1265 | Data truncated for column 'col' at row 1 |
     +---------+------+------------------------------------------+
     1 row in set (0.04 sec)

     mysql> SELECT col FROM myset;
     +------+
     | col  |
     +------+
     | a,d  |
     | a,d  |
     | a,d  |
     | a,d  |
     | a,d  |
     | a,d  |
     +------+
     6 rows in set (0.01 sec)

If strict SQL mode is enabled, attempts to insert invalid *Note `SET':
set. values result in an error.

*Note `SET': set. values are sorted numerically. `NULL' values sort
before non-`NULL' *Note `SET': set.  values.

Functions such as `SUM()' or `AVG()' that expect a numeric argument
cast the argument to a number if necessary. For *Note `SET': set.
values, the cast operation causes the numeric value to be used.

Normally, you search for *Note `SET': set.  values using the
`FIND_IN_SET()' function or the `LIKE' operator:

     mysql> SELECT * FROM TBL_NAME WHERE FIND_IN_SET('VALUE',SET_COL)>0;
     mysql> SELECT * FROM TBL_NAME WHERE SET_COL LIKE '%VALUE%';

The first statement finds rows where SET_COL contains the VALUE set
member. The second is similar, but not the same: It finds rows where
SET_COL contains VALUE anywhere, even as a substring of another set
member.

The following statements also are legal:

     mysql> SELECT * FROM TBL_NAME WHERE SET_COL & 1;
     mysql> SELECT * FROM TBL_NAME WHERE SET_COL = 'VAL1,VAL2';

The first of these statements looks for values containing the first set
member. The second looks for an exact match. Be careful with
comparisons of the second type. Comparing set values to `'VAL1,VAL2''
returns different results than comparing values to `'VAL2,VAL1''.  You
should specify the values in the same order they are listed in the
column definition.

To determine all possible values for a *Note `SET': set. column, use
`SHOW COLUMNS FROM TBL_NAME LIKE SET_COL' and parse the *Note `SET':
set. definition in the `Type' column of the output.

In the C API, *Note `SET': set. values are returned as strings. For
information about using result set metadata to distinguish them from
other strings, see *Note c-api-data-structures::.


File: manual.info,  Node: storage-requirements,  Next: choosing-types,  Prev: string-types,  Up: data-types

11.5 Data Type Storage Requirements
===================================

The storage requirements for data vary, according to the storage engine
being used for the table in question. Different storage engines use
different methods for recording the raw data and different data types.
In addition, some engines may compress the information in a given row,
either on a column or entire row basis, making calculation of the
storage requirements for a given table or column structure.

However, all storage engines must communicate and exchange information
on a given row within a table using the same structure, and this
information is consistent, irrespective of the storage engine used to
write the information to disk.

This sections includes some guideliness and information for the storage
requirements for each data type supported by MySQL, including details
for the internal format and the sizes used by storage engines that used
a fixed size representation for different types. Information is listed
by category or storage engine.

The internal representation of a table has a maximum row size of 65,535
bytes, even if the storage engine is capable of supporting larger rows.
This figure excludes *Note `BLOB': blob. or *Note `TEXT': blob.
columns, which contribute only 9 to 12 bytes toward this size. For
*Note `BLOB': blob. and `TEXT' data, the information is stored
internally in a different area of memory than the row buffer. Different
storage engines handle the allocation and storage of this data in
different ways, according to the method they use for handling the
corresponding types. For more information, see *Note storage-engines::,
and *Note column-count-limit::.

*Important*:

For tables using the *Note `NDBCLUSTER': mysql-cluster.  storage
engine, there is the factor of _4-byte alignment_ to be taken into
account when calculating storage requirements. This means that all
*Note `NDB': mysql-cluster. data storage is done in multiples of 4
bytes. Thus, a column value that would take 15 bytes in a table using a
storage engine other than *Note `NDB': mysql-cluster. requires 16 bytes
in an *Note `NDB': mysql-cluster. table. This requirement applies in
addition to any other considerations that are discussed in this
section. For example, in *Note `NDBCLUSTER': mysql-cluster. tables, the
*Note `TINYINT': numeric-types, *Note `SMALLINT': numeric-types, *Note
`MEDIUMINT': numeric-types, and *Note `INTEGER': numeric-types.  (*Note
`INT': numeric-types.) column types each require 4 bytes storage per
record due to the alignment factor.

An exception to this rule is the *Note `BIT': numeric-types. type,
which is _not_ 4-byte aligned. In MySQL Cluster tables, a `BIT(M)'
column takes M bits of storage space.  However, if a table definition
contains 1 or more *Note `BIT': numeric-types. columns (up to 32 *Note
`BIT': numeric-types. columns), then *Note `NDBCLUSTER': mysql-cluster.
reserves 4 bytes (32 bits) per row for these. If a table definition
contains more than 32 *Note `BIT': numeric-types. columns (up to 64
such columns), then *Note `NDBCLUSTER': mysql-cluster.  reserves 8
bytes (that is, 64 bits) per row.

In addition, while a `NULL' itself does not require any storage space,
*Note `NDBCLUSTER': mysql-cluster. reserves 4 bytes per row if the
table definition contains any columns defined as `NULL', up to 32 `NULL'
columns. (If a MySQL Cluster table is defined with more than 32 `NULL'
columns up to 64 `NULL' columns, then 8 bytes per row is reserved.)

When calculating storage requirements for MySQL Cluster tables, you
must also remember that every table using the *Note `NDBCLUSTER':
mysql-cluster. storage engine requires a primary key; if no primary key
is defined by the user, then a `hidden' primary key will be created by
*Note `NDB': mysql-cluster. This hidden primary key consumes 31-35
bytes per table record.

You may find the `ndb_size.pl' utility to be useful for estimating
*Note `NDB': mysql-cluster. storage requirements. This Perl script
connects to a current MySQL (non-Cluster) database and creates a report
on how much space that database would require if it used the *Note
`NDBCLUSTER': mysql-cluster. storage engine. See *Note
mysql-cluster-programs-ndb-size-pl::, for more information.

* Storage Requirements for Numeric Types *

Data Type                     Storage Required
*Note `TINYINT':              1 byte
numeric-types.                
*Note `SMALLINT':             2 bytes
numeric-types.                
*Note `MEDIUMINT':            3 bytes
numeric-types.                
*Note `INT': numeric-types,   4 bytes
*Note `INTEGER':              
numeric-types.                
*Note `BIGINT':               8 bytes
numeric-types.                
`FLOAT(P)'                    4 bytes if 0 <= P <= 24, 8 bytes if 25 <=
                              P <= 53
*Note `FLOAT': numeric-types. 4 bytes
`DOUBLE [PRECISION]', *Note   8 bytes
`REAL': numeric-types.        
`DECIMAL(M,D)',               Varies; see following discussion
`NUMERIC(M,D)'                
`BIT(M)'                      approximately (M+7)/8 bytes

The storage requirements for *Note `DECIMAL': numeric-types. (and *Note
`NUMERIC': numeric-types.) are version-specific:

As of MySQL 5.0.3, values for *Note `DECIMAL': numeric-types. columns
are represented using a binary format that packs nine decimal (base 10)
digits into four bytes. Storage for the integer and fractional parts of
each value are determined separately. Each multiple of nine digits
requires four bytes, and the `leftover' digits require some fraction of
four bytes. The storage required for excess digits is given by the
following table.

Leftover Digits    Number of Bytes
0                  0
1                  1
2                  1
3                  2
4                  2
5                  3
6                  3
7                  4
8                  4

Before MySQL 5.0.3, *Note `DECIMAL': numeric-types. columns are
represented as strings and storage requirements are: M+2 bytes if D > 0,
`M+1' bytes if D = 0, D+2 if `M < D'

* Storage Requirements for Date and Time Types *

Data Type                     Storage Required
*Note `DATE': datetime.       3 bytes
*Note `TIME': time.           3 bytes
*Note `DATETIME': datetime.   8 bytes
*Note `TIMESTAMP': datetime.  4 bytes
*Note `YEAR': year.           1 byte

For details about internal representation of temporal values, see MySQL
Internals: Important Algorithms and Structures
(http://forge.mysql.com/wiki/MySQL_Internals_Algorithms).

* Storage Requirements for String Types *

In the following table, M represents the declared column length in
characters for nonbinary string types and bytes for binary string types.
L represents the actual length in bytes of a given string value.

Data Type                     Storage Required
`CHAR(M)'                     M x W bytes, 0 `<= M <=' 255, where W is
                              the number of bytes required for the
                              maximum-length character in the character
                              set
`BINARY(M)'                   M bytes, 0 `<= M <=' 255
`VARCHAR(M)', `VARBINARY(M)'  L + 1 bytes if column values require 0 -
                              255 bytes, L + 2 bytes if values may
                              require more than 255 bytes
*Note `TINYBLOB': blob,       L + 1 bytes, where L < 2^8
*Note `TINYTEXT': blob.       
*Note `BLOB': blob, *Note     L + 2 bytes, where L < 2^16
`TEXT': blob.                 
*Note `MEDIUMBLOB': blob,     L + 3 bytes, where L < 2^24
*Note `MEDIUMTEXT': blob.     
*Note `LONGBLOB': blob,       L + 4 bytes, where L < 2^32
*Note `LONGTEXT': blob.       
`ENUM('VALUE1','VALUE2',...)' 1 or 2 bytes, depending on the number of
                              enumeration values (65,535 values maximum)
`SET('VALUE1','VALUE2',...)'  1, 2, 3, 4, or 8 bytes, depending on the
                              number of set members (64 members maximum)

Variable-length string types are stored using a length prefix plus
data. The length prefix requires from one to four bytes depending on
the data type, and the value of the prefix is L (the byte length of the
string). For example, storage for a *Note `MEDIUMTEXT': blob.  value
requires L bytes to store the value plus three bytes to store the
length of the value.

To calculate the number of bytes used to store a particular *Note
`CHAR': char, *Note `VARCHAR': char, or *Note `TEXT': blob. column
value, you must take into account the character set used for that
column and whether the value contains multi-byte characters. In
particular, when using the `utf8' Unicode character set, you must keep
in mind that not all characters use the same number of bytes and can
require up to three bytes per character. For a breakdown of the storage
used for different categories of `utf8' characters, see *Note
charset-unicode::.

*Note `VARCHAR': char, *Note `VARBINARY': binary-varbinary, and the
*Note `BLOB': blob. and *Note `TEXT': blob. types are variable-length
types. For each, the storage requirements depend on these factors:

   * The actual length of the column value

   * The column's maximum possible length

   * The character set used for the column, because some character sets
     contain multi-byte characters

For example, a `VARCHAR(255)' column can hold a string with a maximum
length of 255 characters. Assuming that the column uses the `latin1'
character set (one byte per character), the actual storage required is
the length of the string (L), plus one byte to record the length of the
string. For the string `'abcd'', L is 4 and the storage requirement is
five bytes. If the same column is instead declared to use the `ucs2'
double-byte character set, the storage requirement is 10 bytes: The
length of `'abcd'' is eight bytes and the column requires two bytes to
store lengths because the maximum length is greater than 255 (up to 510
bytes).

The effective maximum number of _bytes_ that can be stored in a *Note
`VARCHAR': char. or *Note `VARBINARY': binary-varbinary. column is
subject to the maximum row size of 65,535 bytes, which is shared among
all columns. For a *Note `VARCHAR': char. column that stores multi-byte
characters, the effective maximum number of _characters_ is less. For
example, `utf8' characters can require up to three bytes per character,
so a *Note `VARCHAR': char. column that uses the `utf8' character set
can be declared to be a maximum of 21,844 characters. See *Note
column-count-limit::.

As of MySQL 5.0.3, the *Note `NDBCLUSTER': mysql-cluster.  engine
supports only fixed-width columns. This means that a *Note `VARCHAR':
char. column from a table in a MySQL Cluster will behave as follows:

   * If the size of the column is fewer than 256 characters, the column
     requires one byte extra storage per row.

   * If the size of the column is 256 characters or more, the column
     requires two bytes extra storage per row.

The number of bytes required per character varies according to the
character set used. For example, if a `VARCHAR(100)' column in a
Cluster table uses the `utf8' character set, each character requires 3
bytes storage. This means that each record in such a column takes up
100 x 3 + 1 = 301 bytes for storage, regardless of the length of the
string actually stored in any given record. For a `VARCHAR(1000)'
column in a table using the *Note `NDBCLUSTER': mysql-cluster. storage
engine with the `utf8' character set, each record will use 1000 x 3 + 2
= 3002 bytes storage; that is, the column is 1,000 characters wide,
each character requires 3 bytes storage, and each record has a 2-byte
overhead because 1,000 >= 256.

*Note `TEXT': blob. and *Note `BLOB': blob. columns are implemented
differently in the NDB Cluster storage engine, wherein each row in a
*Note `TEXT': blob. column is made up of two separate parts. One of
these is of fixed size (256 bytes), and is actually stored in the
original table. The other consists of any data in excess of 256 bytes,
which is stored in a hidden table.  The rows in this second table are
always 2,000 bytes long. This means that the size of a *Note `TEXT':
blob.  column is 256 if SIZE <= 256 (where SIZE represents the size of
the row); otherwise, the size is 256 + SIZE + (2000 - (SIZE - 256) %
2000).

The size of an *Note `ENUM': enum. object is determined by the number
of different enumeration values. One byte is used for enumerations with
up to 255 possible values. Two bytes are used for enumerations having
between 256 and 65,535 possible values. See *Note enum::.

The size of a *Note `SET': set. object is determined by the number of
different set members. If the set size is N, the object occupies
`(N+7)/8' bytes, rounded up to 1, 2, 3, 4, or 8 bytes. A *Note `SET':
set. can have a maximum of 64 members. See *Note set::.


File: manual.info,  Node: choosing-types,  Next: other-vendor-data-types,  Prev: storage-requirements,  Up: data-types

11.6 Choosing the Right Type for a Column
=========================================

For optimum storage, you should try to use the most precise type in all
cases. For example, if an integer column is used for values in the
range from `1' to `99999', `MEDIUMINT UNSIGNED' is the best type. Of
the types that represent all the required values, this type uses the
least amount of storage.

Tables created in MySQL 5.0.3 and above use a new storage format for
*Note `DECIMAL': numeric-types. columns. All basic calculations (`+',
`-', `*', and `/') with *Note `DECIMAL': numeric-types. columns are
done with precision of 65 decimal (base 10) digits. See *Note
numeric-type-overview::.

Prior to MySQL 5.0.3, calculations on *Note `DECIMAL': numeric-types.
values are performed using double-precision operations. If accuracy is
not too important or if speed is the highest priority, the *Note
`DOUBLE': numeric-types. type may be good enough. For high precision,
you can always convert to a fixed-point type stored in a *Note
`BIGINT': numeric-types. This enables you to do all calculations with
64-bit integers and then convert results back to floating-point values
as necessary.

`PROCEDURE ANALYSE' can be used to obtain suggestions for optimal
column data types. For more information, see *Note procedure-analyse::.


File: manual.info,  Node: other-vendor-data-types,  Prev: choosing-types,  Up: data-types

11.7 Using Data Types from Other Database Engines
=================================================

To facilitate the use of code written for SQL implementations from
other vendors, MySQL maps data types as shown in the following table.
These mappings make it easier to import table definitions from other
database systems into MySQL.

Other Vendor Type         MySQL Type
*Note `BOOL':             *Note `TINYINT': numeric-types.
numeric-types.            
*Note `BOOLEAN':          *Note `TINYINT': numeric-types.
numeric-types.            
`CHARACTER VARYING(M)'    `VARCHAR(M)'
*Note `FIXED':            *Note `DECIMAL': numeric-types.
numeric-types.            
*Note `FLOAT4':           *Note `FLOAT': numeric-types.
numeric-types.            
*Note `FLOAT8':           *Note `DOUBLE': numeric-types.
numeric-types.            
*Note `INT1':             *Note `TINYINT': numeric-types.
numeric-types.            
*Note `INT2':             *Note `SMALLINT': numeric-types.
numeric-types.            
*Note `INT3':             *Note `MEDIUMINT': numeric-types.
numeric-types.            
*Note `INT4':             *Note `INT': numeric-types.
numeric-types.            
`INT8'                    *Note `BIGINT': numeric-types.
`LONG VARBINARY'          *Note `MEDIUMBLOB': blob.
`LONG VARCHAR'            *Note `MEDIUMTEXT': blob.
`LONG'                    *Note `MEDIUMTEXT': blob.
*Note `MIDDLEINT':        *Note `MEDIUMINT': numeric-types.
numeric-types.            
*Note `NUMERIC':          *Note `DECIMAL': numeric-types.
numeric-types.            

Data type mapping occurs at table creation time, after which the
original type specifications are discarded. If you create a table with
types used by other vendors and then issue a `DESCRIBE TBL_NAME'
statement, MySQL reports the table structure using the equivalent MySQL
types. For example:

     mysql> CREATE TABLE t (a BOOL, b FLOAT8, c LONG VARCHAR, d NUMERIC);
     Query OK, 0 rows affected (0.00 sec)

     mysql> DESCRIBE t;
     +-------+---------------+------+-----+---------+-------+
     | Field | Type          | Null | Key | Default | Extra |
     +-------+---------------+------+-----+---------+-------+
     | a     | tinyint(1)    | YES  |     | NULL    |       |
     | b     | double        | YES  |     | NULL    |       |
     | c     | mediumtext    | YES  |     | NULL    |       |
     | d     | decimal(10,0) | YES  |     | NULL    |       |
     +-------+---------------+------+-----+---------+-------+
     4 rows in set (0.01 sec)


File: manual.info,  Node: functions,  Next: sql-syntax,  Prev: data-types,  Up: Top

12 Functions and Operators
**************************

* Menu:

* func-op-summary-ref::          Function and Operator Reference
* type-conversion::              Type Conversion in Expression Evaluation
* non-typed-operators::          Operators
* control-flow-functions::       Control Flow Functions
* string-functions::             String Functions
* numeric-functions::            Numeric Functions and Operators
* date-and-time-functions::      Date and Time Functions
* mysql-calendar::               What Calendar Is Used By MySQL?
* fulltext-search::              Full-Text Search Functions
* cast-functions::               Cast Functions and Operators
* bit-functions::                Bit Functions
* encryption-functions::         Encryption and Compression Functions
* information-functions::        Information Functions
* miscellaneous-functions::      Miscellaneous Functions
* group-by-functions-and-modifiers::  Functions and Modifiers for Use with `GROUP BY' Clauses
* spatial-extensions::           Spatial Extensions
* precision-math::               Precision Math

Expressions can be used at several points in SQL statements, such as in
the `ORDER BY' or `HAVING' clauses of *Note `SELECT': select.
statements, in the `WHERE' clause of a *Note `SELECT': select, *Note
`DELETE': delete, or *Note `UPDATE': update. statement, or in *Note
`SET': set-option.  statements. Expressions can be written using
literal values, column values, `NULL', built-in functions, stored
functions, user-defined functions, and operators. This chapter
describes the functions and operators that are permitted for writing
expressions in MySQL. Instructions for writing stored functions and
user-defined functions are given in *Note stored-routines::, and *Note
adding-functions::. See *Note function-resolution::, for the rules
describing how the server interprets references to different kinds of
functions.

An expression that contains `NULL' always produces a `NULL' value
unless otherwise indicated in the documentation for a particular
function or operator.

*Note*:

By default, there must be no whitespace between a function name and the
parenthesis following it. This helps the MySQL parser distinguish
between function calls and references to tables or columns that happen
to have the same name as a function. However, spaces around function
arguments are permitted.

You can tell the MySQL server to accept spaces after function names by
starting it with the `--sql-mode=IGNORE_SPACE' option. (See *Note
server-sql-mode::.) Individual client programs can request this
behavior by using the `CLIENT_IGNORE_SPACE' option for *Note
`mysql_real_connect()': mysql-real-connect. In either case, all
function names become reserved words.

For the sake of brevity, most examples in this chapter display the
output from the *Note `mysql': mysql. program in abbreviated form.
Rather than showing examples in this format:

     mysql> SELECT MOD(29,9);
     +-----------+
     | mod(29,9) |
     +-----------+
     |         2 |
     +-----------+
     1 rows in set (0.00 sec)

This format is used instead:

     mysql> SELECT MOD(29,9);
             -> 2


File: manual.info,  Node: func-op-summary-ref,  Next: type-conversion,  Prev: functions,  Up: functions

12.1 Function and Operator Reference
====================================

*Note*:

This table is part of an ongoing process to expand and simplify the
information provided on these elements. Further improvements to the
table, and corresponding descriptions will be applied over the coming
months.

*Functions/Operators*

Name                          Description
`ABS()'                       Return the absolute value
`ACOS()'                      Return the arc cosine
`ADDDATE()'                   Add time values (intervals) to a date value
`ADDTIME()'                   Add time
`AES_DECRYPT()'               Decrypt using AES
`AES_ENCRYPT()'               Encrypt using AES
`AND', `&&'                   Logical AND
`ASCII()'                     Return numeric value of left-most character
`ASIN()'                      Return the arc sine
`='                           Assign a value (as part of a  *Note `SET':
                              set-option. statement, or  as part of the
                              `SET' clause in an  *Note `UPDATE':
                              update. statement)
`:='                          Assign a value
`ATAN2()', `ATAN()'           Return the arc tangent of the two arguments
`ATAN()'                      Return the arc tangent
`AVG()'                       Return the average value of the argument
`BENCHMARK()'                 Repeatedly execute an expression
`BETWEEN ... AND ... '        Check whether a value is within a range of
                              values
`BIN()'                       Return a string representation of the
                              argument
`BINARY'                      Cast a string to a binary string
`BIT_AND()'                   Return bitwise and
`BIT_COUNT()'                 Return the number of bits that are set
`BIT_LENGTH()'                Return length of argument in bits
`BIT_OR()'                    Return bitwise or
`BIT_XOR()'                   Return bitwise xor
`&'                           Bitwise AND
`~'                           Invert bits
`|'                           Bitwise OR
`^'                           Bitwise XOR
`CASE'                        Case operator
`CAST()'                      Cast a value as a certain type
`CEIL()'                      Return the smallest integer value not less
                              than  the argument
`CEILING()'                   Return the smallest integer value not less
                              than  the argument
`CHAR_LENGTH()'               Return number of characters in argument
`CHAR()'                      Return the character for each integer
                              passed
`CHARACTER_LENGTH()'          A synonym for CHAR_LENGTH()
`CHARSET()'                   Return the character set of the argument
`COALESCE()'                  Return the first non-NULL argument
`COERCIBILITY()'              Return the collation coercibility value of
                              the string  argument
`COLLATION()'                 Return the collation of the string argument
`COMPRESS()'                  Return result as a binary string
`CONCAT_WS()'                 Return concatenate with  separator
`CONCAT()'                    Return concatenated string
`CONNECTION_ID()'             Return the connection ID (thread ID)  for
                              the connection
`CONV()'                      Convert numbers between different number
                              bases
`CONVERT_TZ()'                Convert from one timezone to another
`CONVERT()'                   Cast a value as a certain type
`COS()'                       Return the cosine
`COT()'                       Return the cotangent
`COUNT(DISTINCT)'             Return the count of a number of different
                              values
`COUNT()'                     Return a count of the number of rows
                              returned
`CRC32()'                     Compute a cyclic redundancy check value
`CURDATE()'                   Return the current date
`CURRENT_DATE()',             Synonyms for CURDATE()
`CURRENT_DATE'                
`CURRENT_TIME()',             Synonyms for CURTIME()
`CURRENT_TIME'                
`CURRENT_TIMESTAMP()',        Synonyms for NOW()
`CURRENT_TIMESTAMP'           
`CURRENT_USER()',             The authenticated user name and host name
`CURRENT_USER'                
`CURTIME()'                   Return the current time
`DATABASE()'                  Return the default (current) database name
`DATE_ADD()'                  Add time values (intervals) to a date value
`DATE_FORMAT()'               Format date as specified
`DATE_SUB()'                  Subtract a time value (interval) from a
                              date
`DATE()'                      Extract the date part of a date or
                              datetime expression
`DATEDIFF()'                  Subtract two dates
`DAY()'                       Synonym for DAYOFMONTH()
`DAYNAME()'                   Return the name of the weekday
`DAYOFMONTH()'                Return the day of the month (0-31)
`DAYOFWEEK()'                 Return the weekday index of the argument
`DAYOFYEAR()'                 Return the day of the year (1-366)
`DECODE()'                    Decodes a string encrypted using ENCODE()
`DEFAULT()'                   Return the default value for a table column
`DEGREES()'                   Convert radians to degrees
`DES_DECRYPT()'               Decrypt a string
`DES_ENCRYPT()'               Encrypt a string
`DIV'                         Integer division
`/'                           Division operator
`ELT()'                       Return string at index number
`ENCODE()'                    Encode a string
`ENCRYPT()'                   Encrypt a string
`<=>'                         NULL-safe equal to operator
`='                           Equal operator
`EXP()'                       Raise to the power of
`EXPORT_SET()'                Return a string such that for every bit
                              set in the value  bits, you get an on
                              string and for every unset bit, you get an
                              off string
`EXTRACT()'                   Extract part of a date
`FIELD()'                     Return the index (position) of the first
                              argument  in the subsequent arguments
`FIND_IN_SET()'               Return the index position of  the first
                              argument within the second argument
`FLOOR()'                     Return the largest integer value not
                              greater than  the argument
`FORMAT()'                    Return a number formatted to specified
                              number of decimal places
`FOUND_ROWS()'                For a SELECT with a LIMIT clause, the
                              number of rows that would be returned were
                              there no LIMIT clause
`FROM_DAYS()'                 Convert a day number to a date
`FROM_UNIXTIME()'             Format UNIX timestamp as a date
`GET_FORMAT()'                Return a date format string
`GET_LOCK()'                  Get a named lock
`>='                          Greater than or equal operator
`>'                           Greater than operator
`GREATEST()'                  Return the largest argument
`GROUP_CONCAT()'              Return a concatenated string
`HEX()'                       Return a hexadecimal representation of a
                              decimal or string value
`HOUR()'                      Extract the hour
`IF()'                        If/else construct
`IFNULL()'                    Null if/else construct
`IN()'                        Check whether a value is within a set of
                              values
`INET_ATON()'                 Return the numeric value of an IP address
`INET_NTOA()'                 Return the IP address from a numeric value
`INSERT()'                    Insert a substring at the specified
                              position up to  the specified number of
                              characters
`INSTR()'                     Return the index of the first occurrence
                              of substring
`INTERVAL()'                  Return the index of the argument  that is
                              less than the first argument
`IS_FREE_LOCK()'              Checks whether the named lock  is free
`IS NOT NULL'                 NOT NULL value test
`IS NOT'                      Test a value against a boolean
`IS NULL'                     NULL value test
`IS_USED_LOCK()'              Checks whether the named lock is in use.
                              Return connection identifier if true.
`IS'                          Test a value against a boolean
`ISNULL()'                    Test whether the argument is NULL
`LAST_DAY'                    Return the last day of the month for the
                              argument
`LAST_INSERT_ID()'            Value of the AUTOINCREMENT column  for the
                              last INSERT
`LCASE()'                     Synonym for LOWER()
`LEAST()'                     Return the smallest argument
`<<'                          Left shift
`LEFT()'                      Return the leftmost number of characters
                              as specified
`LENGTH()'                    Return the length of a string in bytes
`<='                          Less than or equal operator
`<'                           Less than operator
`LIKE'                        Simple pattern matching
`LN()'                        Return the natural logarithm of the
                              argument
`LOAD_FILE()'                 Load the named file
`LOCALTIME()', `LOCALTIME'    Synonym for NOW()
`LOCALTIMESTAMP',             Synonym for NOW()
`LOCALTIMESTAMP()'            
`LOCATE()'                    Return the position of the first
                              occurrence  of substring
`LOG10()'                     Return the base-10 logarithm of the
                              argument
`LOG2()'                      Return the base-2 logarithm of the argument
`LOG()'                       Return the natural logarithm of the first
                              argument
`LOWER()'                     Return the argument in lowercase
`LPAD()'                      Return the string argument, left-padded
                              with the specified string
`LTRIM()'                     Remove leading spaces
`MAKE_SET()'                  Return a set of comma-separated strings
                              that have the corresponding bit in bits set
`MAKEDATE()'                  Create a date from the year and day of year
`MAKETIME'                    MAKETIME()
`MASTER_POS_WAIT()'           Block until the slave has read and
                              applied all updates up to the specified
                              position
`MATCH'                       Perform full-text search
`MAX()'                       Return the maximum value
`MD5()'                       Calculate MD5 checksum
`MICROSECOND()'               Return the microseconds from argument
`MID()'                       Return a substring starting from the
                              specified position
`MIN()'                       Return the minimum value
`-'                           Minus operator
`MINUTE()'                    Return the minute from the argument
`MOD()'                       Return the remainder
`% or MOD'                    Modulo operator
`MONTH()'                     Return the month from the date passed
`MONTHNAME()'                 Return the name of the month
`NAME_CONST()'                Causes the column to have the given name
`NOT BETWEEN ... AND ...'     Check whether a value is not within a
                              range of values
`!=', `<>'                    Not equal operator
`NOT IN()'                    Check whether a value is not within a set
                              of values
`NOT LIKE'                    Negation of simple pattern matching
`NOT REGEXP'                  Negation of REGEXP
`NOT', `!'                    Negates value
`NOW()'                       Return the current date and time
`NULLIF()'                    Return NULL if expr1 = expr2
`OCT()'                       Return an octal representation of a
                              decimal  number
`OCTET_LENGTH()'              A synonym for LENGTH()
`OLD_PASSWORD()'              Return the value of the  pre-4.1
                              implementation of PASSWORD
`||', `OR'                    Logical OR
`ORD()'                       Return character code for leftmost
                              character of the  argument
`PASSWORD()'                  Calculate and return a password string
`PERIOD_ADD()'                Add a period to a year-month
`PERIOD_DIFF()'               Return the number of months between periods
`PI()'                        Return the value of pi
`+'                           Addition operator
`POSITION()'                  A synonym for LOCATE()
`POW()'                       Return the argument raised to the
                              specified power
`POWER()'                     Return the argument raised to the
                              specified power
*Note `PROCEDURE ANALYSE()':  Analyze the results of a query
procedure-analyse.            
`QUARTER()'                   Return the quarter from a date argument
`QUOTE()'                     Escape the argument for use in an SQL
                              statement
`RADIANS()'                   Return argument converted to radians
`RAND()'                      Return a random floating-point value
`REGEXP'                      Pattern matching using regular expressions
`RELEASE_LOCK()'              Releases the named lock
`REPEAT()'                    Repeat a string the specified number of
                              times
`REPLACE()'                   Replace occurrences of a specified string
`REVERSE()'                   Reverse the characters in a string
`>>'                          Right shift
`RIGHT()'                     Return the specified rightmost number of
                              characters
`RLIKE'                       Synonym for REGEXP
`ROUND()'                     Round the argument
`ROW_COUNT()'                 The number of rows  updated
`RPAD()'                      Append string the specified number of times
`RTRIM()'                     Remove trailing spaces
`SCHEMA()'                    A synonym for DATABASE()
`SEC_TO_TIME()'               Converts seconds to 'HH:MM:SS' format
`SECOND()'                    Return the second (0-59)
`SESSION_USER()'              Synonym for USER()
`SHA1()', `SHA()'             Calculate an SHA-1 160-bit checksum
`SIGN()'                      Return the sign of the argument
`SIN()'                       Return the sine of the argument
`SLEEP()'                     Sleep for a number of seconds
`SOUNDEX()'                   Return a soundex string
`SOUNDS LIKE'                 Compare sounds
`SPACE()'                     Return a string of the specified number of
                              spaces
`SQRT()'                      Return the square root of the argument
`STD()'                       Return the population standard deviation
`STDDEV_POP()'                Return the population standard deviation
`STDDEV_SAMP()'               Return the sample standard deviation
`STDDEV()'                    Return the population standard deviation
`STR_TO_DATE()'               Convert a string to a date
`STRCMP()'                    Compare two strings
`SUBDATE()'                   A synonym for DATE_SUB() when invoked with
                              three arguments
`SUBSTR()'                    Return the substring as specified
`SUBSTRING_INDEX()'           Return a substring from a  string before
                              the specified number of occurrences of the
                              delimiter
`SUBSTRING()'                 Return the substring as specified
`SUBTIME()'                   Subtract times
`SUM()'                       Return the sum
`SYSDATE()'                   Return the time at which the function
                              executes
`SYSTEM_USER()'               Synonym for USER()
`TAN()'                       Return the tangent of the argument
`TIME_FORMAT()'               Format as time
`TIME_TO_SEC()'               Return the argument converted to seconds
`TIME()'                      Extract the time portion of the expression
                              passed
`TIMEDIFF()'                  Subtract time
`*'                           Multiplication operator
`TIMESTAMP()'                 With a single argument, this function
                              returns the date or  datetime expression;
                              with two arguments, the sum of the
                              arguments
`TIMESTAMPADD()'              Add an interval to a datetime expression
`TIMESTAMPDIFF()'             Subtract an interval from a datetime
                              expression
`TO_DAYS()'                   Return the date argument converted to days
`TRIM()'                      Remove leading and trailing spaces
`TRUNCATE()'                  Truncate to specified number of decimal
                              places
`UCASE()'                     Synonym for UPPER()
`-'                           Change the sign of the argument
`UNCOMPRESS()'                Uncompress a string compressed
`UNCOMPRESSED_LENGTH()'       Return the length of a string before
                              compression
`UNHEX()'                     Convert each pair of hexadecimal digits
                              to a character
`UNIX_TIMESTAMP()'            Return a UNIX timestamp
`UPPER()'                     Convert to uppercase
`USER()'                      The user name and host name provided by
                              the client
`UTC_DATE()'                  Return the current UTC date
`UTC_TIME()'                  Return the current UTC time
`UTC_TIMESTAMP()'             Return the current UTC date and time
`UUID()'                      Return a Universal Unique Identifier (UUID)
`VALUES()'                    Defines the values to be used during an
                              INSERT
`VAR_POP()'                   Return the population standard variance
`VAR_SAMP()'                  Return the sample variance
`VARIANCE()'                  Return the population standard variance
`VERSION()'                   Returns a string that indicates the MySQL
                              server version
`WEEK()'                      Return the week number
`WEEKDAY()'                   Return the weekday index
`WEEKOFYEAR()'                Return the calendar week of the date (0-53)
`XOR'                         Logical XOR
`YEAR()'                      Return the year
`YEARWEEK()'                  Return the year and week


File: manual.info,  Node: type-conversion,  Next: non-typed-operators,  Prev: func-op-summary-ref,  Up: functions

12.2 Type Conversion in Expression Evaluation
=============================================

When an operator is used with operands of different types, type
conversion occurs to make the operands compatible. Some conversions
occur implicitly. For example, MySQL automatically converts numbers to
strings as necessary, and vice versa.

     mysql> SELECT 1+'1';
             -> 2
     mysql> SELECT CONCAT(2,' test');
             -> '2 test'

It is also possible to convert a number to a string explicitly using
the `CAST()' function.  Conversion occurs implicitly with the
`CONCAT()' function because it expects string arguments.

     mysql> SELECT 38.8, CAST(38.8 AS CHAR);
             -> 38.8, '38.8'
     mysql> SELECT 38.8, CONCAT(38.8);
             -> 38.8, '38.8'

See later in this section for information about the character set of
implicit number-to-string conversions.

The following rules describe how conversion occurs for comparison
operations:

   * If one or both arguments are `NULL', the result of the comparison
     is `NULL', except for the `NULL'-safe `<=>' equality comparison
     operator. For `NULL <=> NULL', the result is true. No conversion
     is needed.

   * If both arguments in a comparison operation are strings, they are
     compared as strings.

   * If both arguments are integers, they are compared as integers.

   * Hexadecimal values are treated as binary strings if not compared
     to a number.

   * If one of the arguments is a *Note `TIMESTAMP': datetime. or *Note
     `DATETIME': datetime. column and the other argument is a constant,
     the constant is converted to a timestamp before the comparison is
     performed. This is done to be more ODBC-friendly. Note that this
     is not done for the arguments to `IN()'! To be safe, always use
     complete datetime, date, or time strings when doing comparisons.
     For example, to achieve best results when using `BETWEEN' with
     date or time values, use `CAST()' to explicitly convert the values
     to the desired data type.

   * If one of the arguments is a decimal value, comparison depends on
     the other argument. The arguments are compared as decimal values
     if the other argument is a decimal or integer value, or as
     floating-point values if the other argument is a floating-point
     value.

   * In all other cases, the arguments are compared as floating-point
     (real) numbers.

For information about conversion of values from one temporal type to
another, see *Note date-and-time-type-conversion::.

The following examples illustrate conversion of strings to numbers for
comparison operations:

     mysql> SELECT 1 > '6x';
             -> 0
     mysql> SELECT 7 > '6x';
             -> 1
     mysql> SELECT 0 > 'x6';
             -> 0
     mysql> SELECT 0 = 'x6';
             -> 1

For comparisons of a string column with a number, MySQL cannot use an
index on the column to look up the value quickly. If STR_COL is an
indexed string column, the index cannot be used when performing the
lookup in the following statement:

     SELECT * FROM TBL_NAME WHERE STR_COL=1;

The reason for this is that there are many different strings that may
convert to the value `1', such as `'1'', `' 1'', or `'1a''.

Comparisons that use floating-point numbers (or values that are
converted to floating-point numbers) are approximate because such
numbers are inexact. This might lead to results that appear
inconsistent:

     mysql> SELECT '18015376320243458' = 18015376320243458;
             -> 1
     mysql> SELECT '18015376320243459' = 18015376320243459;
             -> 0

Such results can occur because the values are converted to
floating-point numbers, which have only 53 bits of precision and are
subject to rounding:

     mysql> SELECT '18015376320243459'+0.0;
             -> 1.8015376320243e+16

Furthermore, the conversion from string to floating-point and from
integer to floating-point do not necessarily occur the same way.  The
integer may be converted to floating-point by the CPU, whereas the
string is converted digit by digit in an operation that involves
floating-point multiplications.

The results shown will vary on different systems, and can be affected
by factors such as computer architecture or the compiler version or
optimization level. One way to avoid such problems is to use `CAST()'
so that a value will not be converted implicitly to a float-point
number:

     mysql> SELECT CAST('18015376320243459' AS UNSIGNED) = 18015376320243459;
             -> 1

For more information about floating-point comparisons, see *Note
problems-with-float::.

Implicit conversion of a numeric or temporal value to a string produces
a binary string (a *Note `BINARY': binary-varbinary, *Note `VARBINARY':
binary-varbinary, or *Note `BLOB': blob. value). Such implicit
conversions to string typically occur for functions that are passed
numeric or temporal values when string values are more usual, and thus
can have effects beyond the type of the converted value. Consider the
expression `CONCAT(1, 'abc')'. The numeric argument `1' is converted to
the binary string `'1'' and the concatenation of that value with the
nonbinary string `'abc'' produces the binary string `'1abc''.


File: manual.info,  Node: non-typed-operators,  Next: control-flow-functions,  Prev: type-conversion,  Up: functions

12.3 Operators
==============

* Menu:

* operator-precedence::          Operator Precedence
* comparison-operators::         Comparison Functions and Operators
* logical-operators::            Logical Operators
* assignment-operators::         Assignment Operators

*Operators*

Name                          Description
`AND', `&&'                   Logical AND
`='                           Assign a value (as part of a  *Note `SET':
                              set-option. statement, or  as part of the
                              `SET' clause in an  *Note `UPDATE':
                              update. statement)
`:='                          Assign a value
`BETWEEN ... AND ... '        Check whether a value is within a range of
                              values
`BINARY'                      Cast a string to a binary string
`&'                           Bitwise AND
`~'                           Invert bits
`|'                           Bitwise OR
`^'                           Bitwise XOR
`CASE'                        Case operator
`DIV'                         Integer division
`/'                           Division operator
`<=>'                         NULL-safe equal to operator
`='                           Equal operator
`>='                          Greater than or equal operator
`>'                           Greater than operator
`IS NOT NULL'                 NOT NULL value test
`IS NOT'                      Test a value against a boolean
`IS NULL'                     NULL value test
`IS'                          Test a value against a boolean
`<<'                          Left shift
`<='                          Less than or equal operator
`<'                           Less than operator
`LIKE'                        Simple pattern matching
`-'                           Minus operator
`% or MOD'                    Modulo operator
`NOT BETWEEN ... AND ...'     Check whether a value is not within a
                              range of values
`!=', `<>'                    Not equal operator
`NOT LIKE'                    Negation of simple pattern matching
`NOT REGEXP'                  Negation of REGEXP
`NOT', `!'                    Negates value
`||', `OR'                    Logical OR
`+'                           Addition operator
`REGEXP'                      Pattern matching using regular expressions
`>>'                          Right shift
`RLIKE'                       Synonym for REGEXP
`SOUNDS LIKE'                 Compare sounds
`*'                           Multiplication operator
`-'                           Change the sign of the argument
`XOR'                         Logical XOR


File: manual.info,  Node: operator-precedence,  Next: comparison-operators,  Prev: non-typed-operators,  Up: non-typed-operators

12.3.1 Operator Precedence
--------------------------

Operator precedences are shown in the following list, from highest
precedence to the lowest. Operators that are shown together on a line
have the same precedence.

     INTERVAL
     BINARY, COLLATE
     !
     - (unary minus), ~ (unary bit inversion)
     ^
     *, /, DIV, %, MOD
     -, +
     <<, >>
     &
     |
     = (comparison), <=>, >=, >, <=, <, <>, !=, IS, LIKE, REGEXP, IN
     BETWEEN, CASE, WHEN, THEN, ELSE
     NOT
     &&, AND
     XOR
     ||, OR
     = (assignment), :=

The precedence of `=' depends on whether it is used as a comparison
operator (`=') or as an assignment operator (`='). When used as a
comparison operator, it has the same precedence as `<=>', `>=', `>',
`<=', `<', `<>', `!=', `IS', `LIKE', `REGEXP', and `IN'. When used as
an assignment operator, it has the same precedence as `:='.  *Note
set-option::, and *Note user-variables::, explain how MySQL determines
which interpretation of `=' should apply.

The meaning of some operators depends on the SQL mode:

   * By default, `||' is a logical `OR' operator. With
     `PIPES_AS_CONCAT' enabled, `||' is string concatenation, with a
     precedence between `^' and the unary operators.

   * By default, `!' has a higher precedence than `NOT' as of MySQL
     5.0.2. For earlier versions, or from 5.0.2 on with
     `HIGH_NOT_PRECEDENCE' enabled, `!' and `NOT' have the same
     precedence.

See *Note server-sql-mode::.

The precedence of operators determines the order of evaluation of terms
in an expression. To override this order and group terms explicitly,
use parentheses. For example:

     mysql> SELECT 1+2*3;
             -> 7
     mysql> SELECT (1+2)*3;
             -> 9


File: manual.info,  Node: comparison-operators,  Next: logical-operators,  Prev: operator-precedence,  Up: non-typed-operators

12.3.2 Comparison Functions and Operators
-----------------------------------------

*Comparison Operators*

Name                          Description
`BETWEEN ... AND ... '        Check whether a value is within a range of
                              values
`COALESCE()'                  Return the first non-NULL argument
`<=>'                         NULL-safe equal to operator
`='                           Equal operator
`>='                          Greater than or equal operator
`>'                           Greater than operator
`GREATEST()'                  Return the largest argument
`IN()'                        Check whether a value is within a set of
                              values
`INTERVAL()'                  Return the index of the argument  that is
                              less than the first argument
`IS NOT NULL'                 NOT NULL value test
`IS NOT'                      Test a value against a boolean
`IS NULL'                     NULL value test
`IS'                          Test a value against a boolean
`ISNULL()'                    Test whether the argument is NULL
`LEAST()'                     Return the smallest argument
`<='                          Less than or equal operator
`<'                           Less than operator
`LIKE'                        Simple pattern matching
`NOT BETWEEN ... AND ...'     Check whether a value is not within a
                              range of values
`!=', `<>'                    Not equal operator
`NOT IN()'                    Check whether a value is not within a set
                              of values
`NOT LIKE'                    Negation of simple pattern matching
`STRCMP()'                    Compare two strings

Comparison operations result in a value of `1' (`TRUE'), `0' (`FALSE'),
or `NULL'. These operations work for both numbers and strings. Strings
are automatically converted to numbers and numbers to strings as
necessary.

The following relational comparison operators can be used to compare
not only scalar operands, but row operands:

     =  >  <  >=  <=  <>  !=

For examples of row comparisons, see *Note row-subqueries::.

Some of the functions in this section (such as `LEAST()' and
`GREATEST()') return values other than `1' (`TRUE'), `0' (`FALSE'), or
`NULL'. However, the value they return is based on comparison
operations performed according to the rules described in *Note
type-conversion::.

To convert a value to a specific type for comparison purposes, you can
use the `CAST()' function.  String values can be converted to a
different character set using `CONVERT()'. See *Note cast-functions::.

By default, string comparisons are not case sensitive and use the
current character set. The default is `latin1' (cp1252 West European),
which also works well for English.

   *  `='

     Equal:

          mysql> SELECT 1 = 0;
                  -> 0
          mysql> SELECT '0' = 0;
                  -> 1
          mysql> SELECT '0.0' = 0;
                  -> 1
          mysql> SELECT '0.01' = 0;
                  -> 0
          mysql> SELECT '.01' = 0.01;
                  -> 1

   *  `<=>'

     `NULL'-safe equal. This operator performs an equality comparison
     like the `=' operator, but returns `1' rather than `NULL' if both
     operands are `NULL', and `0' rather than `NULL' if one operand is
     `NULL'.

          mysql> SELECT 1 <=> 1, NULL <=> NULL, 1 <=> NULL;
                  -> 1, 1, 0
          mysql> SELECT 1 = 1, NULL = NULL, 1 = NULL;
                  -> 1, NULL, NULL

   *  `<>', `!='

     Not equal:

          mysql> SELECT '.01' <> '0.01';
                  -> 1
          mysql> SELECT .01 <> '0.01';
                  -> 0
          mysql> SELECT 'zapp' <> 'zappp';
                  -> 1

   *  `<='

     Less than or equal:

          mysql> SELECT 0.1 <= 2;
                  -> 1

   *  `<'

     Less than:

          mysql> SELECT 2 < 2;
                  -> 0

   *  `>='

     Greater than or equal:

          mysql> SELECT 2 >= 2;
                  -> 1

   *  `>'

     Greater than:

          mysql> SELECT 2 > 2;
                  -> 0

   *  `IS BOOLEAN_VALUE'

     Tests a value against a boolean value, where BOOLEAN_VALUE can be
     `TRUE', `FALSE', or `UNKNOWN'.

          mysql> SELECT 1 IS TRUE, 0 IS FALSE, NULL IS UNKNOWN;
                  -> 1, 1, 1

     `IS BOOLEAN_VALUE' syntax was added in MySQL 5.0.2.

   *  `IS NOT BOOLEAN_VALUE'

     Tests a value against a boolean value, where BOOLEAN_VALUE can be
     `TRUE', `FALSE', or `UNKNOWN'.

          mysql> SELECT 1 IS NOT UNKNOWN, 0 IS NOT UNKNOWN, NULL IS NOT UNKNOWN;
                  -> 1, 1, 0

     `IS NOT BOOLEAN_VALUE' syntax was added in MySQL 5.0.2.

   *  `IS NULL'

     Tests whether a value is `NULL'.

          mysql> SELECT 1 IS NULL, 0 IS NULL, NULL IS NULL;
                  -> 0, 0, 1

     To work well with ODBC programs, MySQL supports the following
     extra features when using `IS NULL':

        * If `sql_auto_is_null' variable is set to 1 (the default),
          then after a statement that successfully inserts an
          automatically generated `AUTO_INCREMENT' value, you can find
          that value by issuing a statement of the following form:

               SELECT * FROM TBL_NAME WHERE AUTO_COL IS NULL

          If the statement returns a row, the value returned is the
          same as if you invoked the `LAST_INSERT_ID()' function. For
          details, including the return value after a multiple-row
          insert, see *Note information-functions::. If no
          `AUTO_INCREMENT' value was successfully inserted, the *Note
          `SELECT': select.  statement returns no row.

          The behavior of retrieving an `AUTO_INCREMENT' value by using
          an `IS NULL' comparison can be disabled by setting
          `sql_auto_is_null = 0'.  See *Note server-system-variables::.

        * For *Note `DATE': datetime. and *Note `DATETIME': datetime.
          columns that are declared as `NOT NULL', you can find the
          special date `'0000-00-00'' by using a statement like this:

               SELECT * FROM TBL_NAME WHERE DATE_COLUMN IS NULL

          This is needed to get some ODBC applications to work because
          ODBC does not support a `'0000-00-00'' date value.

          See *Note
          connector-odbc-usagenotes-functionality-last-insert-id::, and
          the description for the `FLAG_AUTO_IS_NULL' option at *Note
          connector-odbc-configuration-connection-parameters::.

   *  `IS NOT NULL'

     Tests whether a value is not `NULL'.

          mysql> SELECT 1 IS NOT NULL, 0 IS NOT NULL, NULL IS NOT NULL;
                  -> 1, 1, 0

   *  `EXPR BETWEEN MIN AND MAX'

     If EXPR is greater than or equal to MIN and EXPR is less than or
     equal to MAX, `BETWEEN' returns `1', otherwise it returns `0'.
     This is equivalent to the expression `(MIN <= EXPR AND EXPR <=
     MAX)' if all the arguments are of the same type. Otherwise type
     conversion takes place according to the rules described in *Note
     type-conversion::, but applied to all the three arguments.

          mysql> SELECT 2 BETWEEN 1 AND 3, 2 BETWEEN 3 and 1;
                  -> 1, 0
          mysql> SELECT 1 BETWEEN 2 AND 3;
                  -> 0
          mysql> SELECT 'b' BETWEEN 'a' AND 'c';
                  -> 1
          mysql> SELECT 2 BETWEEN 2 AND '3';
                  -> 1
          mysql> SELECT 2 BETWEEN 2 AND 'x-3';
                  -> 0

     For best results when using `BETWEEN' with date or time values,
     use `CAST()' to explicitly convert the values to the desired data
     type.  Examples: If you compare a *Note `DATETIME': datetime. to
     two *Note `DATE': datetime. values, convert the *Note `DATE':
     datetime. values to *Note `DATETIME': datetime. values. If you use
     a string constant such as `'2001-1-1'' in a comparison to a *Note
     `DATE': datetime, cast the string to a *Note `DATE': datetime.

   *  `EXPR NOT BETWEEN MIN AND MAX'

     This is the same as `NOT (EXPR BETWEEN MIN AND MAX)'.

   *  `COALESCE(VALUE,...)'

     Returns the first non-`NULL' value in the list, or `NULL' if there
     are no non-`NULL' values.

          mysql> SELECT COALESCE(NULL,1);
                  -> 1
          mysql> SELECT COALESCE(NULL,NULL,NULL);
                  -> NULL

   *  `GREATEST(VALUE1,VALUE2,...)'

     With two or more arguments, returns the largest (maximum-valued)
     argument. The arguments are compared using the same rules as for
     `LEAST()'.

          mysql> SELECT GREATEST(2,0);
                  -> 2
          mysql> SELECT GREATEST(34.0,3.0,5.0,767.0);
                  -> 767.0
          mysql> SELECT GREATEST('B','A','C');
                  -> 'C'

     Before MySQL 5.0.13, `GREATEST()' returns `NULL' only if all
     arguments are `NULL'. As of 5.0.13, it returns `NULL' if any
     argument is `NULL'.

   *  `EXPR IN (VALUE,...)'

     Returns `1' if EXPR is equal to any of the values in the `IN'
     list, else returns `0'. If all values are constants, they are
     evaluated according to the type of EXPR and sorted. The search for
     the item then is done using a binary search. This means `IN' is
     very quick if the `IN' value list consists entirely of constants.
     Otherwise, type conversion takes place according to the rules
     described in *Note type-conversion::, but applied to all the
     arguments.

          mysql> SELECT 2 IN (0,3,5,7);
                  -> 0
          mysql> SELECT 'wefwf' IN ('wee','wefwf','weg');
                  -> 1

     You should never mix quoted and unquoted values in an `IN' list
     because the comparison rules for quoted values (such as strings)
     and unquoted values (such as numbers) differ. Mixing types may
     therefore lead to inconsistent results. For example, do not write
     an `IN' expression like this:

          SELECT val1 FROM tbl1 WHERE val1 IN (1,2,'a');

     Instead, write it like this:

          SELECT val1 FROM tbl1 WHERE val1 IN ('1','2','a');

     The number of values in the `IN' list is only limited by the
     `max_allowed_packet' value.

     To comply with the SQL standard, `IN' returns `NULL' not only if
     the expression on the left hand side is `NULL', but also if no
     match is found in the list and one of the expressions in the list
     is `NULL'.

     `IN()' syntax can also be used to write certain types of
     subqueries. See *Note any-in-some-subqueries::.

   *  `EXPR NOT IN (VALUE,...)'

     This is the same as `NOT (EXPR IN (VALUE,...))'.

   *  `ISNULL(EXPR)'

     If EXPR is `NULL', `ISNULL()' returns `1', otherwise it returns
     `0'.

          mysql> SELECT ISNULL(1+1);
                  -> 0
          mysql> SELECT ISNULL(1/0);
                  -> 1

     `ISNULL()' can be used instead of `=' to test whether a value is
     `NULL'. (Comparing a value to `NULL' using `=' always yields
     false.)

     The `ISNULL()' function shares some special behaviors with the `IS
     NULL' comparison operator. See the description of `IS NULL'.

   *  `INTERVAL(N,N1,N2,N3,...)'

     Returns `0' if N < N1, `1' if N < N2 and so on or `-1' if N is
     `NULL'. All arguments are treated as integers. It is required that
     N1 < N2 < N3 < `...' < NN for this function to work correctly.
     This is because a binary search is used (very fast).

          mysql> SELECT INTERVAL(23, 1, 15, 17, 30, 44, 200);
                  -> 3
          mysql> SELECT INTERVAL(10, 1, 10, 100, 1000);
                  -> 2
          mysql> SELECT INTERVAL(22, 23, 30, 44, 200);
                  -> 0

   *  `LEAST(VALUE1,VALUE2,...)'

     With two or more arguments, returns the smallest (minimum-valued)
     argument. The arguments are compared using the following rules:

        * If the return value is used in an *Note `INTEGER':
          numeric-types. context or all arguments are integer-valued,
          they are compared as integers.

        * If the return value is used in a *Note `REAL': numeric-types.
          context or all arguments are real-valued, they are compared
          as reals.

        * If the arguments comprise a mix of numbers and strings, they
          are compared as numbers.

        * If any argument is a nonbinary (character) string, the
          arguments are compared as nonbinary strings.

        * In all other cases, the arguments are compared as binary
          strings.

     Before MySQL 5.0.13, `LEAST()' returns `NULL' only if all
     arguments are `NULL'. As of 5.0.13, it returns `NULL' if any
     argument is `NULL'.

          mysql> SELECT LEAST(2,0);
                  -> 0
          mysql> SELECT LEAST(34.0,3.0,5.0,767.0);
                  -> 3.0
          mysql> SELECT LEAST('B','A','C');
                  -> 'A'

     Note that the preceding conversion rules can produce strange
     results in some borderline cases:

          mysql> SELECT CAST(LEAST(3600, 9223372036854775808.0) as SIGNED);
                  -> -9223372036854775808

     This happens because MySQL reads `9223372036854775808.0' in an
     integer context. The integer representation is not good enough to
     hold the value, so it wraps to a signed integer.


File: manual.info,  Node: logical-operators,  Next: assignment-operators,  Prev: comparison-operators,  Up: non-typed-operators

12.3.3 Logical Operators
------------------------

*Logical Operators*

Name                          Description
`AND', `&&'                   Logical AND
`NOT', `!'                    Negates value
`||', `OR'                    Logical OR
`XOR'                         Logical XOR

In SQL, all logical operators evaluate to `TRUE', `FALSE', or `NULL'
(`UNKNOWN'). In MySQL, these are implemented as 1 (`TRUE'), 0
(`FALSE'), and `NULL'. Most of this is common to different SQL database
servers, although some servers may return any nonzero value for `TRUE'.

MySQL evaluates any nonzero, non-`NULL' value to `TRUE'. For example,
the following statements all assess to `TRUE':

     mysql> SELECT 10 IS TRUE;
     -> 1
     mysql> SELECT -10 IS TRUE;
     -> 1
     mysql> SELECT 'string' IS NOT NULL;
     -> 1

   *  `NOT', `!'

     Logical NOT. Evaluates to `1' if the operand is `0', to `0' if the
     operand is nonzero, and `NOT NULL' returns `NULL'.

          mysql> SELECT NOT 10;
                  -> 0
          mysql> SELECT NOT 0;
                  -> 1
          mysql> SELECT NOT NULL;
                  -> NULL
          mysql> SELECT ! (1+1);
                  -> 0
          mysql> SELECT ! 1+1;
                  -> 1

     The last example produces `1' because the expression evaluates the
     same way as `(!1)+1'.

     Note that the precedence of the `NOT' operator changed in MySQL
     5.0.2. See *Note operator-precedence::.

   *  `AND', `&&'

     Logical AND. Evaluates to `1' if all operands are nonzero and not
     `NULL', to `0' if one or more operands are `0', otherwise `NULL' is
     returned.

          mysql> SELECT 1 && 1;
                  -> 1
          mysql> SELECT 1 && 0;
                  -> 0
          mysql> SELECT 1 && NULL;
                  -> NULL
          mysql> SELECT 0 && NULL;
                  -> 0
          mysql> SELECT NULL && 0;
                  -> 0

   *  `OR', `||'

     Logical OR. When both operands are non-`NULL', the result is `1'
     if any operand is nonzero, and `0' otherwise. With a `NULL'
     operand, the result is `1' if the other operand is nonzero, and
     `NULL' otherwise. If both operands are `NULL', the result is
     `NULL'.

          mysql> SELECT 1 || 1;
                  -> 1
          mysql> SELECT 1 || 0;
                  -> 1
          mysql> SELECT 0 || 0;
                  -> 0
          mysql> SELECT 0 || NULL;
                  -> NULL
          mysql> SELECT 1 || NULL;
                  -> 1

   *  `XOR'

     Logical XOR. Returns `NULL' if either operand is `NULL'. For
     non-`NULL' operands, evaluates to `1' if an odd number of operands
     is nonzero, otherwise `0' is returned.

          mysql> SELECT 1 XOR 1;
                  -> 0
          mysql> SELECT 1 XOR 0;
                  -> 1
          mysql> SELECT 1 XOR NULL;
                  -> NULL
          mysql> SELECT 1 XOR 1 XOR 1;
                  -> 1

     `a XOR b' is mathematically equal to `(a AND (NOT b)) OR ((NOT a)
     and b)'.


File: manual.info,  Node: assignment-operators,  Prev: logical-operators,  Up: non-typed-operators

12.3.4 Assignment Operators
---------------------------

*Assignment Operators*

Name                          Description
`='                           Assign a value (as part of a  *Note `SET':
                              set-option. statement, or  as part of the
                              `SET' clause in an  *Note `UPDATE':
                              update. statement)
`:='                          Assign a value

   *  `:='

     Assignment operator. Causes the user variable on the left hand
     side of the operator to take on the value to its right.  The value
     on the right hand side may be a literal value, another variable
     storing a value, or any legal expression that yields a scalar
     value, including the result of a query (provided that this value
     is a scalar value). You can perform multiple assignments in the
     same *Note `SET': set-option.  statement. You can perform multiple
     assignments in the same statement-

     Unlike `=', the `:=' operator is never interpreted as a comparison
     operator. This means you can use `:=' in any valid SQL statement
     (not just in *Note `SET': set-option.  statements) to assign a
     value to a variable.

          mysql> SELECT @var1, @var2;
                  -> NULL, NULL
          mysql> SELECT @var1 := 1, @var2;
                  -> 1, NULL
          mysql> SELECT @var1, @var2;
                  -> 1, NULL
          mysql> SELECT @var1, @var2 := @var1;
                  -> 1, 1
          mysql> SELECT @var1, @var2;
                  -> 1, 1

          mysql> SELECT @var1:=COUNT(*) FROM t1;
                  -> 4
          mysql> SELECT @var1;
                  -> 4

     You can make value assignments using `:=' in other statements
     besides *Note `SELECT': select, such as *Note `UPDATE': update, as
     shown here:

          mysql> SELECT @var1;
                  -> 4
          mysql> SELECT * FROM t1;
                  -> 1, 3, 5, 7

          mysql> UPDATE t1 SET c1 = 2 WHERE c1 = @var1:= 1;
          Query OK, 1 row affected (0.00 sec)
          Rows matched: 1  Changed: 1  Warnings: 0

          mysql> SELECT @var1;
                  -> 1
          mysql> SELECT * FROM t1;
                  -> 2, 3, 5, 7

     While it is also possible both to set and to read the value of the
     same variable in a single SQL statement using the `:=' operator,
     this is not recommended.  *Note user-variables::, explains why you
     should avoid doing this.

   *  `='

     This operator is used to perform value assignments in two cases,
     described in the next two paragraphs.

     Within a *Note `SET': set-option.  statement, `=' is treated as an
     assignment operator that causes the user variable on the left hand
     side of the operator to take on the value to its right. (In other
     words, when used in a *Note `SET': set-option.  statement, `=' is
     treated identically to `:='.)  The value on the right hand side
     may be a literal value, another variable storing a value, or any
     legal expression that yields a scalar value, including the result
     of a query (provided that this value is a scalar value). You can
     perform multiple assignments in the same *Note `SET': set-option.
     statement.

     In the `SET' clause of an *Note `UPDATE': update. statement, `='
     also acts as an assignment operator; in this case, however, it
     causes the column named on the left hand side of the operator to
     assume the value given to the right, provided any `WHERE'
     conditions that are part of the *Note `UPDATE': update. are met.
     You can make multiple assignments in the same `SET' clause of an
     *Note `UPDATE': update. statement.

     In any other context, `=' is treated as a comparison operator.

          mysql> SELECT @var1, @var2;
                  -> NULL, NULL
          mysql> SELECT @var1 := 1, @var2;
                  -> 1, NULL
          mysql> SELECT @var1, @var2;
                  -> 1, NULL
          mysql> SELECT @var1, @var2 := @var1;
                  -> 1, 1
          mysql> SELECT @var1, @var2;
                  -> 1, 1

     For more information, see *Note set-option::, *Note update::, and
     *Note subqueries::.


File: manual.info,  Node: control-flow-functions,  Next: string-functions,  Prev: non-typed-operators,  Up: functions

12.4 Control Flow Functions
===========================

*Flow Control Operators*

Name                          Description
`CASE'                        Case operator
`IF()'                        If/else construct
`IFNULL()'                    Null if/else construct
`NULLIF()'                    Return NULL if expr1 = expr2

   *  `CASE VALUE WHEN [COMPARE_VALUE] THEN RESULT [WHEN
     [COMPARE_VALUE] THEN RESULT ...] [ELSE RESULT] END'

     `CASE WHEN [CONDITION] THEN RESULT [WHEN [CONDITION] THEN RESULT
     ...] [ELSE RESULT] END'

     The first version returns the RESULT where `VALUE=COMPARE_VALUE'.
     The second version returns the result for the first condition that
     is true. If there was no matching result value, the result after
     `ELSE' is returned, or `NULL' if there is no `ELSE' part.

          mysql> SELECT CASE 1 WHEN 1 THEN 'one'
              ->     WHEN 2 THEN 'two' ELSE 'more' END;
                  -> 'one'
          mysql> SELECT CASE WHEN 1>0 THEN 'true' ELSE 'false' END;
                  -> 'true'
          mysql> SELECT CASE BINARY 'B'
              ->     WHEN 'a' THEN 1 WHEN 'b' THEN 2 END;
                  -> NULL

     The return type of a `CASE' expression is the compatible
     aggregated type of all return values, but also depends on the
     context in which it is used.  If used in a string context, the
     result is returned as a string. If used in a numeric context, the
     result is returned as a decimal, real, or integer value.

     *Note*:

     The syntax of the `CASE' _expression_ shown here differs slightly
     from that of the SQL *Note `CASE': case-statement.  _statement_
     described in *Note case-statement::, for use inside stored
     programs. The *Note `CASE': case-statement.  statement cannot have
     an `ELSE NULL' clause, and it is terminated with `END CASE'
     instead of `END'.

   *  `IF(EXPR1,EXPR2,EXPR3)'

     If EXPR1 is `TRUE' (`EXPR1 <> 0' and `EXPR1 <> NULL') then `IF()'
     returns EXPR2; otherwise it returns EXPR3.  `IF()' returns a
     numeric or string value, depending on the context in which it is
     used.

          mysql> SELECT IF(1>2,2,3);
                  -> 3
          mysql> SELECT IF(1<2,'yes','no');
                  -> 'yes'
          mysql> SELECT IF(STRCMP('test','test1'),'no','yes');
                  -> 'no'

     If only one of EXPR2 or EXPR3 is explicitly `NULL', the result
     type of the `IF()' function is the type of the non-`NULL'
     expression.

     The default return type of `IF()' (which may matter when it is
     stored into a temporary table) is calculated as follows.

     Expression                         Return Value
     EXPR2 or EXPR3 returns a string    string
     EXPR2 or EXPR3 returns a           floating-point
     floating-point value               
     EXPR2 or EXPR3 returns an integer  integer

     If EXPR2 and EXPR3 are both strings, the result is case sensitive
     if either string is case sensitive.

     *Note*:

     There is also an *Note `IF': if-statement.  _statement_, which
     differs from the `IF()' _function_ described here. See *Note
     if-statement::.

   *  `IFNULL(EXPR1,EXPR2)'

     If EXPR1 is not `NULL', `IFNULL()' returns EXPR1; otherwise it
     returns EXPR2.  `IFNULL()' returns a numeric or string value,
     depending on the context in which it is used.

          mysql> SELECT IFNULL(1,0);
                  -> 1
          mysql> SELECT IFNULL(NULL,10);
                  -> 10
          mysql> SELECT IFNULL(1/0,10);
                  -> 10
          mysql> SELECT IFNULL(1/0,'yes');
                  -> 'yes'

     The default result value of `IFNULL(EXPR1,EXPR2)' is the more
     `general' of the two expressions, in the order `STRING', *Note
     `REAL': numeric-types, or *Note `INTEGER': numeric-types. Consider
     the case of a table based on expressions or where MySQL must
     internally store a value returned by `IFNULL()' in a temporary
     table:


          mysql> CREATE TABLE tmp SELECT IFNULL(1,'test') AS test;
          mysql> DESCRIBE tmp;
          +-------+--------------+------+-----+---------+-------+
          | Field | Type         | Null | Key | Default | Extra |
          +-------+--------------+------+-----+---------+-------+
          | test  | varbinary(4) | NO   |     |         |       |
          +-------+--------------+------+-----+---------+-------+

     In this example, the type of the `test' column is *Note
     `VARBINARY(4)': binary-varbinary.

   *  `NULLIF(EXPR1,EXPR2)'

     Returns `NULL' if `EXPR1 = EXPR2' is true, otherwise returns
     EXPR1. This is the same as `CASE WHEN EXPR1 = EXPR2 THEN NULL ELSE
     EXPR1 END'.

          mysql> SELECT NULLIF(1,1);
                  -> NULL
          mysql> SELECT NULLIF(1,2);
                  -> 1

     Note that MySQL evaluates EXPR1 twice if the arguments are not
     equal.


File: manual.info,  Node: string-functions,  Next: numeric-functions,  Prev: control-flow-functions,  Up: functions

12.5 String Functions
=====================

* Menu:

* string-comparison-functions::  String Comparison Functions
* regexp::                       Regular Expressions

*String Operators*

Name                          Description
`ASCII()'                     Return numeric value of left-most character
`BIN()'                       Return a string representation of the
                              argument
`BIT_LENGTH()'                Return length of argument in bits
`CHAR_LENGTH()'               Return number of characters in argument
`CHAR()'                      Return the character for each integer
                              passed
`CHARACTER_LENGTH()'          A synonym for CHAR_LENGTH()
`CONCAT_WS()'                 Return concatenate with  separator
`CONCAT()'                    Return concatenated string
`ELT()'                       Return string at index number
`EXPORT_SET()'                Return a string such that for every bit
                              set in the value  bits, you get an on
                              string and for every unset bit, you get an
                              off string
`FIELD()'                     Return the index (position) of the first
                              argument  in the subsequent arguments
`FIND_IN_SET()'               Return the index position of  the first
                              argument within the second argument
`FORMAT()'                    Return a number formatted to specified
                              number of decimal places
`HEX()'                       Return a hexadecimal representation of a
                              decimal or string value
`INSERT()'                    Insert a substring at the specified
                              position up to  the specified number of
                              characters
`INSTR()'                     Return the index of the first occurrence
                              of substring
`LCASE()'                     Synonym for LOWER()
`LEFT()'                      Return the leftmost number of characters
                              as specified
`LENGTH()'                    Return the length of a string in bytes
`LIKE'                        Simple pattern matching
`LOAD_FILE()'                 Load the named file
`LOCATE()'                    Return the position of the first
                              occurrence  of substring
`LOWER()'                     Return the argument in lowercase
`LPAD()'                      Return the string argument, left-padded
                              with the specified string
`LTRIM()'                     Remove leading spaces
`MAKE_SET()'                  Return a set of comma-separated strings
                              that have the corresponding bit in bits set
`MATCH'                       Perform full-text search
`MID()'                       Return a substring starting from the
                              specified position
`NOT LIKE'                    Negation of simple pattern matching
`NOT REGEXP'                  Negation of REGEXP
`OCTET_LENGTH()'              A synonym for LENGTH()
`ORD()'                       Return character code for leftmost
                              character of the  argument
`POSITION()'                  A synonym for LOCATE()
`QUOTE()'                     Escape the argument for use in an SQL
                              statement
`REGEXP'                      Pattern matching using regular expressions
`REPEAT()'                    Repeat a string the specified number of
                              times
`REPLACE()'                   Replace occurrences of a specified string
`REVERSE()'                   Reverse the characters in a string
`RIGHT()'                     Return the specified rightmost number of
                              characters
`RLIKE'                       Synonym for REGEXP
`RPAD()'                      Append string the specified number of times
`RTRIM()'                     Remove trailing spaces
`SOUNDEX()'                   Return a soundex string
`SOUNDS LIKE'                 Compare sounds
`SPACE()'                     Return a string of the specified number of
                              spaces
`STRCMP()'                    Compare two strings
`SUBSTR()'                    Return the substring as specified
`SUBSTRING_INDEX()'           Return a substring from a  string before
                              the specified number of occurrences of the
                              delimiter
`SUBSTRING()'                 Return the substring as specified
`TRIM()'                      Remove leading and trailing spaces
`UCASE()'                     Synonym for UPPER()
`UNHEX()'                     Convert each pair of hexadecimal digits
                              to a character
`UPPER()'                     Convert to uppercase

String-valued functions return `NULL' if the length of the result would
be greater than the value of the `max_allowed_packet' system variable.
See *Note server-parameters::.

For functions that operate on string positions, the first position is
numbered 1.

For functions that take length arguments, noninteger arguments are
rounded to the nearest integer.

   *  `ASCII(STR)'

     Returns the numeric value of the leftmost character of the string
     STR. Returns `0' if STR is the empty string. Returns `NULL' if STR
     is `NULL'.  `ASCII()' works for 8-bit characters.

          mysql> SELECT ASCII('2');
                  -> 50
          mysql> SELECT ASCII(2);
                  -> 50
          mysql> SELECT ASCII('dx');
                  -> 100

     See also the `ORD()' function.

   *  `BIN(N)'

     Returns a string representation of the binary value of N, where N
     is a longlong (*Note `BIGINT': numeric-types.) number. This is
     equivalent to `CONV(N,10,2)'.  Returns `NULL' if N is `NULL'.

          mysql> SELECT BIN(12);
                  -> '1100'

   *  `BIT_LENGTH(STR)'

     Returns the length of the string STR in bits.

          mysql> SELECT BIT_LENGTH('text');
                  -> 32

   *  `CHAR(N,...  [USING CHARSET_NAME])'

     `CHAR()' interprets each argument N as an integer and returns a
     string consisting of the characters given by the code values of
     those integers. `NULL' values are skipped.

          mysql> SELECT CHAR(77,121,83,81,'76');
                  -> 'MySQL'
          mysql> SELECT CHAR(77,77.3,'77.3');
                  -> 'MMM'

     As of MySQL 5.0.15, `CHAR()' arguments larger than 255 are
     converted into multiple result bytes. For example, `CHAR(256)' is
     equivalent to `CHAR(1,0)', and `CHAR(256*256)' is equivalent to
     `CHAR(1,0,0)':

          mysql> SELECT HEX(CHAR(1,0)), HEX(CHAR(256));
          +----------------+----------------+
          | HEX(CHAR(1,0)) | HEX(CHAR(256)) |
          +----------------+----------------+
          | 0100           | 0100           |
          +----------------+----------------+
          mysql> SELECT HEX(CHAR(1,0,0)), HEX(CHAR(256*256));
          +------------------+--------------------+
          | HEX(CHAR(1,0,0)) | HEX(CHAR(256*256)) |
          +------------------+--------------------+
          | 010000           | 010000             |
          +------------------+--------------------+

     By default, `CHAR()' returns a binary string. To produce a string
     in a given character set, use the optional `USING' clause:

          mysql> SELECT CHARSET(CHAR(0x65)), CHARSET(CHAR(0x65 USING utf8));
          +---------------------+--------------------------------+
          | CHARSET(CHAR(0x65)) | CHARSET(CHAR(0x65 USING utf8)) |
          +---------------------+--------------------------------+
          | binary              | utf8                           |
          +---------------------+--------------------------------+

     If `USING' is given and the result string is illegal for the given
     character set, a warning is issued.  Also, if strict SQL mode is
     enabled, the result from `CHAR()' becomes `NULL'.

     Before MySQL 5.0.15, `CHAR()' returns a string in the connection
     character set and the `USING' clause is unavailable. In addition,
     each argument is interpreted modulo 256, so `CHAR(256)' and
     `CHAR(256*256)' both are equivalent to `CHAR(0)'.

   *  `CHAR_LENGTH(STR)'

     Returns the length of the string STR, measured in characters. A
     multi-byte character counts as a single character. This means that
     for a string containing five two-byte characters, `LENGTH()'
     returns `10', whereas `CHAR_LENGTH()' returns `5'.

   *  `CHARACTER_LENGTH(STR)'

     `CHARACTER_LENGTH()' is a synonym for `CHAR_LENGTH()'.

   *  `CONCAT(STR1,STR2,...)'

     Returns the string that results from concatenating the arguments.
     May have one or more arguments. If all arguments are nonbinary
     strings, the result is a nonbinary string. If the arguments
     include any binary strings, the result is a binary string. A
     numeric argument is converted to its equivalent binary string
     form; if you want to avoid that, you can use an explicit type
     cast, as in this example:

          SELECT CONCAT(CAST(INT_COL AS CHAR), CHAR_COL);

     `CONCAT()' returns `NULL' if any argument is `NULL'.

          mysql> SELECT CONCAT('My', 'S', 'QL');
                  -> 'MySQL'
          mysql> SELECT CONCAT('My', NULL, 'QL');
                  -> NULL
          mysql> SELECT CONCAT(14.3);
                  -> '14.3'

     For quoted strings, concatenation can be performed by placing the
     strings next to each other:

          mysql> SELECT 'My' 'S' 'QL';
                  -> 'MySQL'

   *  `CONCAT_WS(SEPARATOR,STR1,STR2,...)'

     `CONCAT_WS()' stands for Concatenate With Separator and is a
     special form of `CONCAT()'. The first argument is the separator
     for the rest of the arguments. The separator is added between the
     strings to be concatenated. The separator can be a string, as can
     the rest of the arguments. If the separator is `NULL', the result
     is `NULL'.

          mysql> SELECT CONCAT_WS(',','First name','Second name','Last Name');
                  -> 'First name,Second name,Last Name'
          mysql> SELECT CONCAT_WS(',','First name',NULL,'Last Name');
                  -> 'First name,Last Name'

     `CONCAT_WS()' does not skip empty strings. However, it does skip
     any `NULL' values after the separator argument.

   *  `ELT(N,STR1,STR2,STR3,...)'

     Returns STR1 if N = `1', STR2 if N = `2', and so on. Returns
     `NULL' if N is less than `1' or greater than the number of
     arguments.  `ELT()' is the complement of `FIELD()'.

          mysql> SELECT ELT(1, 'ej', 'Heja', 'hej', 'foo');
                  -> 'ej'
          mysql> SELECT ELT(4, 'ej', 'Heja', 'hej', 'foo');
                  -> 'foo'

   *  `EXPORT_SET(BITS,ON,OFF[,SEPARATOR[,NUMBER_OF_BITS]])'

     Returns a string such that for every bit set in the value BITS,
     you get an ON string and for every bit not set in the value, you
     get an OFF string. Bits in BITS are examined from right to left
     (from low-order to high-order bits).  Strings are added to the
     result from left to right, separated by the SEPARATOR string (the
     default being the comma character ``,''). The number of bits
     examined is given by NUMBER_OF_BITS, which has a default of 64 if
     not specified.  NUMBER_OF_BITS is silently clipped to 64 if larger
     than 64. It is treated as an unsigned integer, so a value of -1 is
     effectively the same as 64.

          mysql> SELECT EXPORT_SET(5,'Y','N',',',4);
                  -> 'Y,N,Y,N'
          mysql> SELECT EXPORT_SET(6,'1','0',',',10);
                  -> '0,1,1,0,0,0,0,0,0,0'

   *  `FIELD(STR,STR1,STR2,STR3,...)'

     Returns the index (position) of STR in the STR1, STR2, STR3, `...'
     list.  Returns `0' if STR is not found.

     If all arguments to `FIELD()' are strings, all arguments are
     compared as strings. If all arguments are numbers, they are
     compared as numbers.  Otherwise, the arguments are compared as
     double.

     If STR is `NULL', the return value is `0' because `NULL' fails
     equality comparison with any value. `FIELD()' is the complement of
     `ELT()'.

          mysql> SELECT FIELD('ej', 'Hej', 'ej', 'Heja', 'hej', 'foo');
                  -> 2
          mysql> SELECT FIELD('fo', 'Hej', 'ej', 'Heja', 'hej', 'foo');
                  -> 0

   *  `FIND_IN_SET(STR,STRLIST)'

     Returns a value in the range of 1 to N if the string STR is in the
     string list STRLIST consisting of N substrings. A string list is a
     string composed of substrings separated by ``,'' characters. If
     the first argument is a constant string and the second is a column
     of type *Note `SET': set, the `FIND_IN_SET()' function is
     optimized to use bit arithmetic. Returns `0' if STR is not in
     STRLIST or if STRLIST is the empty string.  Returns `NULL' if
     either argument is `NULL'. This function does not work properly if
     the first argument contains a comma (``,'') character.

          mysql> SELECT FIND_IN_SET('b','a,b,c,d');
                  -> 2

   *  `FORMAT(X,D)'

     Formats the number X to a format like `'#,###,###.##'', rounded to
     D decimal places, and returns the result as a string. If D is `0',
     the result has no decimal point or fractional part. D should be a
     constant value.

          mysql> SELECT FORMAT(12332.123456, 4);
                  -> '12,332.1235'
          mysql> SELECT FORMAT(12332.1,4);
                  -> '12,332.1000'
          mysql> SELECT FORMAT(12332.2,0);
                  -> '12,332'

   *  `HEX(STR)', `HEX(N)'

     For a string argument STR, `HEX()' returns a hexadecimal string
     representation of STR where each character in STR is converted to
     two hexadecimal digits. The inverse of this operation is performed
     by the `UNHEX()' function.

     For a numeric argument N, `HEX()' returns a hexadecimal string
     representation of the value of N treated as a longlong (*Note
     `BIGINT': numeric-types.) number. This is equivalent to
     `CONV(N,10,16)'.  The inverse of this operation is performed by
     `CONV(HEX(N),16,10)'.

          mysql> SELECT 0x616263, HEX('abc'), UNHEX(HEX('abc'));
                  -> 'abc', 616263, 'abc'
          mysql> SELECT HEX(255), CONV(HEX(255),16,10);
                  -> 'FF', 255

   *  `INSERT(STR,POS,LEN,NEWSTR)'

     Returns the string STR, with the substring beginning at position
     POS and LEN characters long replaced by the string NEWSTR. Returns
     the original string if POS is not within the length of the string.
     Replaces the rest of the string from position POS if LEN is not
     within the length of the rest of the string. Returns `NULL' if any
     argument is `NULL'.

          mysql> SELECT INSERT('Quadratic', 3, 4, 'What');
                  -> 'QuWhattic'
          mysql> SELECT INSERT('Quadratic', -1, 4, 'What');
                  -> 'Quadratic'
          mysql> SELECT INSERT('Quadratic', 3, 100, 'What');
                  -> 'QuWhat'

     This function is multi-byte safe.

   *  `INSTR(STR,SUBSTR)'

     Returns the position of the first occurrence of substring SUBSTR
     in string STR. This is the same as the two-argument form of
     `LOCATE()', except that the order of the arguments is reversed.

          mysql> SELECT INSTR('foobarbar', 'bar');
                  -> 4
          mysql> SELECT INSTR('xbar', 'foobar');
                  -> 0

     This function is multi-byte safe, and is case sensitive only if at
     least one argument is a binary string.

   *  `LCASE(STR)'

     `LCASE()' is a synonym for `LOWER()'.

   *  `LEFT(STR,LEN)'

     Returns the leftmost LEN characters from the string STR, or `NULL'
     if any argument is `NULL'.

          mysql> SELECT LEFT('foobarbar', 5);
                  -> 'fooba'

   *  `LENGTH(STR)'

     Returns the length of the string STR, measured in bytes. A
     multi-byte character counts as multiple bytes. This means that for
     a string containing five two-byte characters, `LENGTH()' returns
     `10', whereas `CHAR_LENGTH()' returns `5'.

          mysql> SELECT LENGTH('text');
                  -> 4

   *  `LOAD_FILE(FILE_NAME)'

     Reads the file and returns the file contents as a string. To use
     this function, the file must be located on the server host, you
     must specify the full path name to the file, and you must have the
     `FILE' privilege.  The file must be readable by all and its size
     less than `max_allowed_packet' bytes. If the `secure_file_priv'
     system variable is set to a nonempty directory name, the file to be
     loaded must be located in that directory.

     If the file does not exist or cannot be read because one of the
     preceding conditions is not satisfied, the function returns `NULL'.

     As of MySQL 5.0.19, the `character_set_filesystem' system variable
     controls interpretation of file names that are given as literal
     strings.

          mysql> UPDATE t
                      SET blob_col=LOAD_FILE('/tmp/picture')
                      WHERE id=1;

   *  `LOCATE(SUBSTR,STR)', `LOCATE(SUBSTR,STR,POS)'

     The first syntax returns the position of the first occurrence of
     substring SUBSTR in string STR. The second syntax returns the
     position of the first occurrence of substring SUBSTR in string
     STR, starting at position POS. Returns `0' if SUBSTR is not in STR.

          mysql> SELECT LOCATE('bar', 'foobarbar');
                  -> 4
          mysql> SELECT LOCATE('xbar', 'foobar');
                  -> 0
          mysql> SELECT LOCATE('bar', 'foobarbar', 5);
                  -> 7

     This function is multi-byte safe, and is case-sensitive only if at
     least one argument is a binary string.

   *  `LOWER(STR)'

     Returns the string STR with all characters changed to lowercase
     according to the current character set mapping. The default is
     `latin1' (cp1252 West European).

          mysql> SELECT LOWER('QUADRATICALLY');
                  -> 'quadratically'

     `LOWER()' (and `UPPER()') are ineffective when applied to binary
     strings (*Note `BINARY': binary-varbinary, *Note `VARBINARY':
     binary-varbinary, *Note `BLOB': blob.). To perform lettercase
     conversion, convert the string to a nonbinary string:

          mysql> SET @str = BINARY 'New York';
          mysql> SELECT LOWER(@str), LOWER(CONVERT(@str USING latin1));
          +-------------+-----------------------------------+
          | LOWER(@str) | LOWER(CONVERT(@str USING latin1)) |
          +-------------+-----------------------------------+
          | New York    | new york                          |
          +-------------+-----------------------------------+

     This function is multi-byte safe.

   *  `LPAD(STR,LEN,PADSTR)'

     Returns the string STR, left-padded with the string PADSTR to a
     length of LEN characters. If STR is longer than LEN, the return
     value is shortened to LEN characters.

          mysql> SELECT LPAD('hi',4,'??');
                  -> '??hi'
          mysql> SELECT LPAD('hi',1,'??');
                  -> 'h'

   *  `LTRIM(STR)'

     Returns the string STR with leading space characters removed.

          mysql> SELECT LTRIM('  barbar');
                  -> 'barbar'

     This function is multi-byte safe.

   *  `MAKE_SET(BITS,STR1,STR2,...)'

     Returns a set value (a string containing substrings separated by
     ``,'' characters) consisting of the strings that have the
     corresponding bit in BITS set.  STR1 corresponds to bit 0, STR2 to
     bit 1, and so on.  `NULL' values in STR1, STR2, `...' are not
     appended to the result.

          mysql> SELECT MAKE_SET(1,'a','b','c');
                  -> 'a'
          mysql> SELECT MAKE_SET(1 | 4,'hello','nice','world');
                  -> 'hello,world'
          mysql> SELECT MAKE_SET(1 | 4,'hello','nice',NULL,'world');
                  -> 'hello'
          mysql> SELECT MAKE_SET(0,'a','b','c');
                  -> ''

   *  `MID(STR,POS,LEN)'

     `MID(STR,POS,LEN)' is a synonym for `SUBSTRING(STR,POS,LEN)'.

   *  `OCT(N)'

     Returns a string representation of the octal value of N, where N
     is a longlong (*Note `BIGINT': numeric-types.) number. This is
     equivalent to `CONV(N,10,8)'.  Returns `NULL' if N is `NULL'.

          mysql> SELECT OCT(12);
                  -> '14'

   *  `OCTET_LENGTH(STR)'

     `OCTET_LENGTH()' is a synonym for `LENGTH()'.

   *  `ORD(STR)'

     If the leftmost character of the string STR is a multi-byte
     character, returns the code for that character, calculated from the
     numeric values of its constituent bytes using this formula:

            (1st byte code)
          + (2nd byte code * 256)
          + (3rd byte code * 256^2) ...

     If the leftmost character is not a multi-byte character, `ORD()'
     returns the same value as the `ASCII()' function.

          mysql> SELECT ORD('2');
                  -> 50

   *  `POSITION(SUBSTR IN STR)'

     `POSITION(SUBSTR IN STR)' is a synonym for `LOCATE(SUBSTR,STR)'.

   *  `QUOTE(STR)'

     Quotes a string to produce a result that can be used as a properly
     escaped data value in an SQL statement. The string is returned
     enclosed by single quotation marks and with each instance of
     backslash (``\''), single quote (``'''), ASCII `NUL', and
     Control+Z preceded by a backslash.  If the argument is `NULL', the
     return value is the word `NULL' without enclosing single quotation
     marks.

          mysql> SELECT QUOTE('Don\'t!');
                  -> 'Don\'t!'
          mysql> SELECT QUOTE(NULL);
                  -> NULL

     For comparison, see the quoting rules for literal strings and
     within the C API in *Note string-literals::, and *Note
     mysql-real-escape-string::.

   *  `REPEAT(STR,COUNT)'

     Returns a string consisting of the string STR repeated COUNT
     times. If COUNT is less than 1, returns an empty string. Returns
     `NULL' if STR or COUNT are `NULL'.

          mysql> SELECT REPEAT('MySQL', 3);
                  -> 'MySQLMySQLMySQL'

   *  `REPLACE(STR,FROM_STR,TO_STR)'

     Returns the string STR with all occurrences of the string FROM_STR
     replaced by the string TO_STR.  `REPLACE()' performs a
     case-sensitive match when searching for FROM_STR.

          mysql> SELECT REPLACE('www.mysql.com', 'w', 'Ww');
                  -> 'WwWwWw.mysql.com'

     This function is multi-byte safe.

   *  `REVERSE(STR)'

     Returns the string STR with the order of the characters reversed.

          mysql> SELECT REVERSE('abc');
                  -> 'cba'

     This function is multi-byte safe.

   *  `RIGHT(STR,LEN)'

     Returns the rightmost LEN characters from the string STR, or
     `NULL' if any argument is `NULL'.

          mysql> SELECT RIGHT('foobarbar', 4);
                  -> 'rbar'

     This function is multi-byte safe.

   *  `RPAD(STR,LEN,PADSTR)'

     Returns the string STR, right-padded with the string PADSTR to a
     length of LEN characters. If STR is longer than LEN, the return
     value is shortened to LEN characters.

          mysql> SELECT RPAD('hi',5,'?');
                  -> 'hi???'
          mysql> SELECT RPAD('hi',1,'?');
                  -> 'h'

     This function is multi-byte safe.

   *  `RTRIM(STR)'

     Returns the string STR with trailing space characters removed.

          mysql> SELECT RTRIM('barbar   ');
                  -> 'barbar'

     This function is multi-byte safe.

   *  `SOUNDEX(STR)'

     Returns a soundex string from STR.  Two strings that sound almost
     the same should have identical soundex strings. A standard soundex
     string is four characters long, but the `SOUNDEX()' function
     returns an arbitrarily long string. You can use `SUBSTRING()' on
     the result to get a standard soundex string. All nonalphabetic
     characters in STR are ignored. All international alphabetic
     characters outside the A-Z range are treated as vowels.

     *Important*:

     When using `SOUNDEX()', you should be aware of the following
     limitations:

        * This function, as currently implemented, is intended to work
          well with strings that are in the English language only.
          Strings in other languages may not produce reliable results.

        * This function is not guaranteed to provide consistent results
          with strings that use multi-byte character sets, including
          `utf-8'.

          We hope to remove these limitations in a future release.  See
          Bug #22638 for more information.

          mysql> SELECT SOUNDEX('Hello');
                  -> 'H400'
          mysql> SELECT SOUNDEX('Quadratically');
                  -> 'Q36324'

     *Note*:

     This function implements the original Soundex algorithm, not the
     more popular enhanced version (also described by D.  Knuth). The
     difference is that original version discards vowels first and
     duplicates second, whereas the enhanced version discards
     duplicates first and vowels second.

   *  `EXPR1 SOUNDS LIKE EXPR2'

     This is the same as `SOUNDEX(EXPR1) = SOUNDEX(EXPR2)'.

   *  `SPACE(N)'

     Returns a string consisting of N space characters.

          mysql> SELECT SPACE(6);
                  -> '      '

   *  `SUBSTR(STR,POS)', `SUBSTR(STR FROM POS)', `SUBSTR(STR,POS,LEN)',
     `SUBSTR(STR FROM POS FOR LEN)'

     `SUBSTR()' is a synonym for `SUBSTRING()'.

   *  `SUBSTRING(STR,POS)', `SUBSTRING(STR FROM POS)',
     `SUBSTRING(STR,POS,LEN)', `SUBSTRING(STR FROM POS FOR LEN)'

     The forms without a LEN argument return a substring from string STR
     starting at position POS. The forms with a LEN argument return a
     substring LEN characters long from string STR, starting at position
     POS. The forms that use `FROM' are standard SQL syntax. It is also
     possible to use a negative value for POS. In this case, the
     beginning of the substring is POS characters from the end of the
     string, rather than the beginning. A negative value may be used
     for POS in any of the forms of this function.

     For all forms of `SUBSTRING()', the position of the first
     character in the string from which the substring is to be
     extracted is reckoned as `1'.

          mysql> SELECT SUBSTRING('Quadratically',5);
                  -> 'ratically'
          mysql> SELECT SUBSTRING('foobarbar' FROM 4);
                  -> 'barbar'
          mysql> SELECT SUBSTRING('Quadratically',5,6);
                  -> 'ratica'
          mysql> SELECT SUBSTRING('Sakila', -3);
                  -> 'ila'
          mysql> SELECT SUBSTRING('Sakila', -5, 3);
                  -> 'aki'
          mysql> SELECT SUBSTRING('Sakila' FROM -4 FOR 2);
                  -> 'ki'

     This function is multi-byte safe.

     If LEN is less than 1, the result is the empty string.

   *  `SUBSTRING_INDEX(STR,DELIM,COUNT)'

     Returns the substring from string STR before COUNT occurrences of
     the delimiter DELIM. If COUNT is positive, everything to the left
     of the final delimiter (counting from the left) is returned. If
     COUNT is negative, everything to the right of the final delimiter
     (counting from the right) is returned.  `SUBSTRING_INDEX()'
     performs a case-sensitive match when searching for DELIM.

          mysql> SELECT SUBSTRING_INDEX('www.mysql.com', '.', 2);
                  -> 'www.mysql'
          mysql> SELECT SUBSTRING_INDEX('www.mysql.com', '.', -2);
                  -> 'mysql.com'

     This function is multi-byte safe.

   *  `TRIM([{BOTH | LEADING | TRAILING} [REMSTR] FROM] STR)',
     `TRIM([REMSTR FROM] STR)'

     Returns the string STR with all REMSTR prefixes or suffixes
     removed. If none of the specifiers `BOTH', `LEADING', or
     `TRAILING' is given, `BOTH' is assumed.  REMSTR is optional and,
     if not specified, spaces are removed.

          mysql> SELECT TRIM('  bar   ');
                  -> 'bar'
          mysql> SELECT TRIM(LEADING 'x' FROM 'xxxbarxxx');
                  -> 'barxxx'
          mysql> SELECT TRIM(BOTH 'x' FROM 'xxxbarxxx');
                  -> 'bar'
          mysql> SELECT TRIM(TRAILING 'xyz' FROM 'barxxyz');
                  -> 'barx'

     This function is multi-byte safe.

   *  `UCASE(STR)'

     `UCASE()' is a synonym for `UPPER()'.

   *  `UNHEX(STR)'

     For a string argument STR, `UNHEX(STR)' performs the inverse
     operation of `HEX(STR)'.  That is, it interprets each pair of
     characters in the argument as a hexadecimal number and converts it
     to the character represented by the number. The return value is a
     binary string.

          mysql> SELECT UNHEX('4D7953514C');
                  -> 'MySQL'
          mysql> SELECT 0x4D7953514C;
                  -> 'MySQL'
          mysql> SELECT UNHEX(HEX('string'));
                  -> 'string'
          mysql> SELECT HEX(UNHEX('1267'));
                  -> '1267'

     The characters in the argument string must be legal hexadecimal
     digits: `'0'' ..  `'9'', `'A'' ..  `'F'', `'a'' ..  `'f''. If the
     argument contains any nonhexadecimal digits, the result is `NULL':

          mysql> SELECT UNHEX('GG');
          +-------------+
          | UNHEX('GG') |
          +-------------+
          | NULL        |
          +-------------+

     A `NULL' result can occur if the argument to `UNHEX()' is a *Note
     `BINARY': binary-varbinary. column, because values are padded with
     0x00 bytes when stored but those bytes are not stripped on
     retrieval. For example, `'41'' is stored into a `CHAR(3)' column as
     `'41 '' and retrieved as `'41'' (with the trailing pad space
     stripped), so `UNHEX()' for the column value returns `'A''. By
     contrast `'41'' is stored into a `BINARY(3)' column as `'41\0''
     and retrieved as `'41\0'' (with the trailing pad `0x00' byte not
     stripped).  `'\0'' is not a legal hexadecimal digit, so `UNHEX()'
     for the column value returns `NULL'.

     For a numeric argument N, the inverse of `HEX(N)' is not performed
     by `UNHEX()'.  Use `CONV(HEX(N),16,10)' instead. See the
     description of `HEX()'.

   *  `UPPER(STR)'

     Returns the string STR with all characters changed to uppercase
     according to the current character set mapping. The default is
     `latin1' (cp1252 West European).

          mysql> SELECT UPPER('Hej');
                  -> 'HEJ'

     See the description of `LOWER()' for information that also applies
     to `UPPER()', such as information about how to perform lettercase
     conversion of binary strings (*Note `BINARY': binary-varbinary,
     *Note `VARBINARY': binary-varbinary, *Note `BLOB': blob.) for
     which these functions are ineffective.

     This function is multi-byte safe.


File: manual.info,  Node: string-comparison-functions,  Next: regexp,  Prev: string-functions,  Up: string-functions

12.5.1 String Comparison Functions
----------------------------------

*String Comparison Operators*

Name                          Description
`LIKE'                        Simple pattern matching
`NOT LIKE'                    Negation of simple pattern matching
`STRCMP()'                    Compare two strings

If a string function is given a binary string as an argument, the
resulting string is also a binary string. A number converted to a
string is treated as a binary string. This affects only comparisons.

Normally, if any expression in a string comparison is case sensitive,
the comparison is performed in case-sensitive fashion.

   *  `EXPR LIKE PAT [ESCAPE 'ESCAPE_CHAR']'

     Pattern matching using SQL simple regular expression comparison.
     Returns `1' (`TRUE') or `0' (`FALSE'). If either EXPR or PAT is
     `NULL', the result is `NULL'.

     The pattern need not be a literal string. For example, it can be
     specified as a string expression or table column.

     Per the SQL standard, `LIKE' performs matching on a per-character
     basis, thus it can produce results different from the `='
     comparison operator:

          mysql> SELECT 'a"' LIKE 'ae' COLLATE latin1_german2_ci;
          +-----------------------------------------+
          | 'a"' LIKE 'ae' COLLATE latin1_german2_ci |
          +-----------------------------------------+
          |                                       0 |
          +-----------------------------------------+
          mysql> SELECT 'a"' = 'ae' COLLATE latin1_german2_ci;
          +--------------------------------------+
          | 'a"' = 'ae' COLLATE latin1_german2_ci |
          +--------------------------------------+
          |                                    1 |
          +--------------------------------------+

     In particular, trailing spaces are significant, which is not true
     for *Note `CHAR': char. or *Note `VARCHAR': char. comparisons
     performed with the `=' operator:

          mysql> SELECT 'a' = 'a ', 'a' LIKE 'a ';
          +------------+---------------+
          | 'a' = 'a ' | 'a' LIKE 'a ' |
          +------------+---------------+
          |          1 |             0 |
          +------------+---------------+
          1 row in set (0.00 sec)

     With `LIKE' you can use the following two wildcard characters in
     the pattern.

     Character     Description
     `%'           Matches any number of characters, even zero characters
     `_'           Matches exactly one character

          mysql> SELECT 'David!' LIKE 'David_';
                  -> 1
          mysql> SELECT 'David!' LIKE '%D%v%';
                  -> 1

     To test for literal instances of a wildcard character, precede it
     by the escape character. If you do not specify the `ESCAPE'
     character, ``\'' is assumed.

     String        Description
     `\%'          Matches one ``%'' character
     `\_'          Matches one ``_'' character

          mysql> SELECT 'David!' LIKE 'David\_';
                  -> 0
          mysql> SELECT 'David_' LIKE 'David\_';
                  -> 1

     To specify a different escape character, use the `ESCAPE' clause:

          mysql> SELECT 'David_' LIKE 'David|_' ESCAPE '|';
                  -> 1

     The escape sequence should be empty or one character long.  The
     expression must evaluate as a constant at execution time. As of
     MySQL 5.0.16, if the `NO_BACKSLASH_ESCAPES' SQL mode is enabled,
     the sequence cannot be empty.

     The following two statements illustrate that string comparisons
     are not case sensitive unless one of the operands is a binary
     string:

          mysql> SELECT 'abc' LIKE 'ABC';
                  -> 1
          mysql> SELECT 'abc' LIKE BINARY 'ABC';
                  -> 0

     In MySQL, `LIKE' is permitted on numeric expressions. (This is an
     extension to the standard SQL `LIKE'.)

          mysql> SELECT 10 LIKE '1%';
                  -> 1

     *Note*:

     Because MySQL uses C escape syntax in strings (for example, ``\n''
     to represent a newline character), you must double any ``\'' that
     you use in `LIKE' strings. For example, to search for ``\n'',
     specify it as ``\\n''. To search for ``\'', specify it as
     ``\\\\''; this is because the backslashes are stripped once by the
     parser and again when the pattern match is made, leaving a single
     backslash to be matched against.

     Exception: At the end of the pattern string, backslash can be
     specified as ``\\''. At the end of the string, backslash stands
     for itself because there is nothing following to escape. Suppose
     that a table contains the following values:

          mysql> SELECT filename FROM t1;
          +--------------+
          | filename     |
          +--------------+
          | C:           |
          | C:\          |
          | C:\Programs  |
          | C:\Programs\ |
          +--------------+

     To test for values that end with backslash, you can match the
     values using either of the following patterns:

          mysql> SELECT filename, filename LIKE '%\\' FROM t1;
          +--------------+---------------------+
          | filename     | filename LIKE '%\\' |
          +--------------+---------------------+
          | C:           |                   0 |
          | C:\          |                   1 |
          | C:\Programs  |                   0 |
          | C:\Programs\ |                   1 |
          +--------------+---------------------+

          mysql> SELECT filename, filename LIKE '%\\\\' FROM t1;
          +--------------+-----------------------+
          | filename     | filename LIKE '%\\\\' |
          +--------------+-----------------------+
          | C:           |                     0 |
          | C:\          |                     1 |
          | C:\Programs  |                     0 |
          | C:\Programs\ |                     1 |
          +--------------+-----------------------+

   *  `EXPR NOT LIKE PAT [ESCAPE 'ESCAPE_CHAR']'

     This is the same as `NOT (EXPR LIKE PAT [ESCAPE 'ESCAPE_CHAR'])'.

     *Note*:

     Aggregate queries involving `NOT LIKE' comparisons with columns
     containing `NULL' may yield unexpected results. For example,
     consider the following table and data:

          CREATE TABLE foo (bar VARCHAR(10));

          INSERT INTO foo VALUES (NULL), (NULL);

     The query `SELECT COUNT(*) FROM foo WHERE bar LIKE '%baz%';'
     returns `0'. You might assume that `SELECT COUNT(*) FROM foo WHERE
     bar NOT LIKE '%baz%';' would return `2'. However, this is not the
     case: The second query returns `0'. This is because `NULL NOT LIKE
     EXPR' always returns `NULL', regardless of the value of EXPR. The
     same is true for aggregate queries involving `NULL' and
     comparisons using `NOT RLIKE' or `NOT REGEXP'. In such cases, you
     must test explicitly for `NOT NULL' using `OR' (and not `AND'), as
     shown here:

          SELECT COUNT(*) FROM foo WHERE bar NOT LIKE '%baz%' OR bar IS NULL;

   *  `STRCMP(EXPR1,EXPR2)'

     `STRCMP()' returns `0' if the strings are the same, `-1' if the
     first argument is smaller than the second according to the current
     sort order, and `1' otherwise.

          mysql> SELECT STRCMP('text', 'text2');
                  -> -1
          mysql> SELECT STRCMP('text2', 'text');
                  -> 1
          mysql> SELECT STRCMP('text', 'text');
                  -> 0

     `STRCMP()' performs the comparison using the collation of the
     arguments.

          mysql> SET @s1 = _latin1 'x' COLLATE latin1_general_ci;
          mysql> SET @s2 = _latin1 'X' COLLATE latin1_general_ci;
          mysql> SET @s3 = _latin1 'x' COLLATE latin1_general_cs;
          mysql> SET @s4 = _latin1 'X' COLLATE latin1_general_cs;
          mysql> SELECT STRCMP(@s1, @s2), STRCMP(@s3, @s4);
          +------------------+------------------+
          | STRCMP(@s1, @s2) | STRCMP(@s3, @s4) |
          +------------------+------------------+
          |                0 |                1 |
          +------------------+------------------+

     If the collations are incompatible, one of the arguments must be
     converted to be compatible with the other. See *Note
     charset-collation-expressions::.


          mysql> SELECT STRCMP(@s1, @s3);
          ERROR 1267 (HY000) at line 10: Illegal mix of collations (latin1_general_ci,IMPLICIT) and (latin1_general_cs,IMPLICIT) for operation 'strcmp'
          mysql> SELECT STRCMP(@s1, @s3 COLLATE latin1_general_ci);
          +--------------------------------------------+
          | STRCMP(@s1, @s3 COLLATE latin1_general_ci) |
          +--------------------------------------------+
          |                                          0 |
          +--------------------------------------------+


File: manual.info,  Node: regexp,  Prev: string-comparison-functions,  Up: string-functions

12.5.2 Regular Expressions
--------------------------

*String Regular Expression Operators*

Name                          Description
`NOT REGEXP'                  Negation of REGEXP
`REGEXP'                      Pattern matching using regular expressions
`RLIKE'                       Synonym for REGEXP

A regular expression is a powerful way of specifying a pattern for a
complex search.

MySQL uses Henry Spencer's implementation of regular expressions, which
is aimed at conformance with POSIX 1003.2.  MySQL uses the extended
version to support pattern-matching operations performed with the
`REGEXP' operator in SQL statements.

This section summarizes, with examples, the special characters and
constructs that can be used in MySQL for `REGEXP' operations. It does
not contain all the details that can be found in Henry Spencer's
`regex(7)' manual page. That manual page is included in MySQL source
distributions, in the `regex.7' file under the `regex' directory. See
also *Note pattern-matching::.

   *  `EXPR NOT REGEXP PAT', `EXPR NOT RLIKE PAT'

     This is the same as `NOT (EXPR REGEXP PAT)'.

   *  `EXPR REGEXP PAT', `EXPR RLIKE PAT'

     Performs a pattern match of a string expression EXPR against a
     pattern PAT. The pattern can be an extended regular expression.
     The syntax for regular expressions is discussed in *Note regexp::.
     Returns `1' if EXPR matches PAT; otherwise it returns `0'. If
     either EXPR or PAT is `NULL', the result is `NULL'.  `RLIKE' is a
     synonym for `REGEXP', provided for `mSQL' compatibility.

     The pattern need not be a literal string. For example, it can be
     specified as a string expression or table column.

     *Note*:

     Because MySQL uses the C escape syntax in strings (for example,
     ``\n'' to represent the newline character), you must double any
     ``\'' that you use in your `REGEXP' strings.

     `REGEXP' is not case sensitive, except when used with binary
     strings.

          mysql> SELECT 'Monty!' REGEXP '.*';
                  -> 1
          mysql> SELECT 'new*\n*line' REGEXP 'new\\*.\\*line';
                  -> 1
          mysql> SELECT 'a' REGEXP 'A', 'a' REGEXP BINARY 'A';
                  -> 1  0
          mysql> SELECT 'a' REGEXP '^[a-d]';
                  -> 1

     `REGEXP' and `RLIKE' use the character set and collations of the
     arguments when deciding the type of a character and performing the
     comparison. If the arguments have different character sets or
     collations, coercibility rules apply as described in *Note
     charset-collation-expressions::.

     *Warning*:

     The `REGEXP' and `RLIKE' operators work in byte-wise fashion, so
     they are not multi-byte safe and may produce unexpected results
     with multi-byte character sets. In addition, these operators
     compare characters by their byte values and accented characters
     may not compare as equal even if a given collation treats them as
     equal.

A regular expression describes a set of strings. The simplest regular
expression is one that has no special characters in it.  For example,
the regular expression `hello' matches `hello' and nothing else.

Nontrivial regular expressions use certain special constructs so that
they can match more than one string. For example, the regular
expression `hello|word' matches either the string `hello' or the string
`word'.

As a more complex example, the regular expression `B[an]*s' matches any
of the strings `Bananas', `Baaaaas', `Bs', and any other string
starting with a `B', ending with an `s', and containing any number of
`a' or `n' characters in between.

A regular expression for the `REGEXP' operator may use any of the
following special characters and constructs:

   * `^'

     Match the beginning of a string.

          mysql> SELECT 'fo\nfo' REGEXP '^fo$';                   -> 0
          mysql> SELECT 'fofo' REGEXP '^fo';                      -> 1

   * `$'

     Match the end of a string.

          mysql> SELECT 'fo\no' REGEXP '^fo\no$';                 -> 1
          mysql> SELECT 'fo\no' REGEXP '^fo$';                    -> 0

   * `.'

     Match any character (including carriage return and newline).

          mysql> SELECT 'fofo' REGEXP '^f.*$';                    -> 1
          mysql> SELECT 'fo\r\nfo' REGEXP '^f.*$';                -> 1

   * `a*'

     Match any sequence of zero or more `a' characters.

          mysql> SELECT 'Ban' REGEXP '^Ba*n';                     -> 1
          mysql> SELECT 'Baaan' REGEXP '^Ba*n';                   -> 1
          mysql> SELECT 'Bn' REGEXP '^Ba*n';                      -> 1

   * `a+'

     Match any sequence of one or more `a' characters.

          mysql> SELECT 'Ban' REGEXP '^Ba+n';                     -> 1
          mysql> SELECT 'Bn' REGEXP '^Ba+n';                      -> 0

   * `a?'

     Match either zero or one `a' character.

          mysql> SELECT 'Bn' REGEXP '^Ba?n';                      -> 1
          mysql> SELECT 'Ban' REGEXP '^Ba?n';                     -> 1
          mysql> SELECT 'Baan' REGEXP '^Ba?n';                    -> 0

   * `de|abc'

     Match either of the sequences `de' or `abc'.

          mysql> SELECT 'pi' REGEXP 'pi|apa';                     -> 1
          mysql> SELECT 'axe' REGEXP 'pi|apa';                    -> 0
          mysql> SELECT 'apa' REGEXP 'pi|apa';                    -> 1
          mysql> SELECT 'apa' REGEXP '^(pi|apa)$';                -> 1
          mysql> SELECT 'pi' REGEXP '^(pi|apa)$';                 -> 1
          mysql> SELECT 'pix' REGEXP '^(pi|apa)$';                -> 0

   * `(abc)*'

     Match zero or more instances of the sequence `abc'.

          mysql> SELECT 'pi' REGEXP '^(pi)*$';                    -> 1
          mysql> SELECT 'pip' REGEXP '^(pi)*$';                   -> 0
          mysql> SELECT 'pipi' REGEXP '^(pi)*$';                  -> 1

   * `{1}', `{2,3}'

     `{n}' or `{m,n}' notation provides a more general way of writing
     regular expressions that match many occurrences of the previous
     atom (or `piece') of the pattern. `m' and `n' are integers.

        * `a*'

          Can be written as `a{0,}'.

        * `a+'

          Can be written as `a{1,}'.

        * `a?'

          Can be written as `a{0,1}'.

     To be more precise, `a{n}' matches exactly `n' instances of `a'.
     `a{n,}' matches `n' or more instances of `a'.  `a{m,n}' matches `m'
     through `n' instances of `a', inclusive.

     `m' and `n' must be in the range from `0' to `RE_DUP_MAX' (default
     255), inclusive. If both `m' and `n' are given, `m' must be less
     than or equal to `n'.

          mysql> SELECT 'abcde' REGEXP 'a[bcd]{2}e';              -> 0
          mysql> SELECT 'abcde' REGEXP 'a[bcd]{3}e';              -> 1
          mysql> SELECT 'abcde' REGEXP 'a[bcd]{1,10}e';           -> 1

   * `[a-dX]', `[^a-dX]'

     Matches any character that is (or is not, if ^ is used) either
     `a', `b', `c', `d' or `X'. A `-' character between two other
     characters forms a range that matches all characters from the
     first character to the second. For example, `[0-9]' matches any
     decimal digit.  To include a literal `]' character, it must
     immediately follow the opening bracket `['.  To include a literal
     `-' character, it must be written first or last. Any character
     that does not have a defined special meaning inside a `[]' pair
     matches only itself.

          mysql> SELECT 'aXbc' REGEXP '[a-dXYZ]';                 -> 1
          mysql> SELECT 'aXbc' REGEXP '^[a-dXYZ]$';               -> 0
          mysql> SELECT 'aXbc' REGEXP '^[a-dXYZ]+$';              -> 1
          mysql> SELECT 'aXbc' REGEXP '^[^a-dXYZ]+$';             -> 0
          mysql> SELECT 'gheis' REGEXP '^[^a-dXYZ]+$';            -> 1
          mysql> SELECT 'gheisa' REGEXP '^[^a-dXYZ]+$';           -> 0

   * `[.characters.]'

     Within a bracket expression (written using `[' and `]'), matches
     the sequence of characters of that collating element.
     `characters' is either a single character or a character name like
     `newline'. The following table lists the permissible character
     names.

     The following table shows the permissible character names and the
     characters that they match. For characters given as numeric
     values, the values are represented in octal.

     Name              Character         Name              Character
     `NUL'             `0'               `SOH'             `001'
     `STX'             `002'             `ETX'             `003'
     `EOT'             `004'             `ENQ'             `005'
     `ACK'             `006'             `BEL'             `007'
     `alert'           `007'             `BS'              `010'
     `backspace'       `'\b''            `HT'              `011'
     `tab'             `'\t''            `LF'              `012'
     `newline'         `'\n''            `VT'              `013'
     `vertical-tab'    `'\v''            `FF'              `014'
     `form-feed'       `'\f''            `CR'              `015'
     `carriage-return' `'\r''            `SO'              `016'
     `SI'              `017'             `DLE'             `020'
     `DC1'             `021'             `DC2'             `022'
     `DC3'             `023'             `DC4'             `024'
     `NAK'             `025'             `SYN'             `026'
     `ETB'             `027'             `CAN'             `030'
     `EM'              `031'             `SUB'             `032'
     `ESC'             `033'             `IS4'             `034'
     `FS'              `034'             `IS3'             `035'
     `GS'              `035'             `IS2'             `036'
     `RS'              `036'             `IS1'             `037'
     `US'              `037'             `space'           `' ''
     `exclamation-mark'`'!''             `quotation-mark'  `'"''
     `number-sign'     `'#''             `dollar-sign'     `'$''
     `percent-sign'    `'%''             `ampersand'       `'&''
     `apostrophe'      `'\'''            `left-parenthesis'`'(''
     `right-parenthesis'`')''             `asterisk'        `'*''
     `plus-sign'       `'+''             `comma'           `',''
     `hyphen'          `'-''             `hyphen-minus'    `'-''
     `period'          `'.''             `full-stop'       `'.''
     `slash'           `'/''             `solidus'         `'/''
     `zero'            `'0''             `one'             `'1''
     `two'             `'2''             `three'           `'3''
     `four'            `'4''             `five'            `'5''
     `six'             `'6''             `seven'           `'7''
     `eight'           `'8''             `nine'            `'9''
     `colon'           `':''             `semicolon'       `';''
     `less-than-sign'  `'<''             `equals-sign'     `'=''
     `greater-than-sign'`'>''             `question-mark'   `'?''
     `commercial-at'   `'@''             `left-square-bracket'`'[''
     `backslash'       `'\\''            `reverse-solidus' `'\\''
     `right-square-bracket'`']''             `circumflex'      `'^''
     `circumflex-accent'`'^''             `underscore'      `'_''
     `low-line'        `'_''             `grave-accent'    `'`''
     `left-brace'      `'{''             `left-curly-bracket'`'{''
     `vertical-line'   `'|''             `right-brace'     `'}''
     `right-curly-bracket'`'}''             `tilde'           `'~''
     `DEL'             `177'                               

          mysql> SELECT '~' REGEXP '[[.~.]]';                     -> 1
          mysql> SELECT '~' REGEXP '[[.tilde.]]';                 -> 1

   * `[=character_class=]'

     Within a bracket expression (written using `[' and `]'),
     `[=character_class=]' represents an equivalence class. It matches
     all characters with the same collation value, including itself.
     For example, if `o' and `(+)' are the members of an equivalence
     class, `[[=o=]]', `[[=(+)=]]', and `[o(+)]' are all synonymous. An
     equivalence class may not be used as an endpoint of a range.

   * `[:character_class:]'

     Within a bracket expression (written using `[' and `]'),
     `[:character_class:]' represents a character class that matches
     all characters belonging to that class. The following table lists
     the standard class names. These names stand for the character
     classes defined in the `ctype(3)' manual page. A particular locale
     may provide other class names. A character class may not be used
     as an endpoint of a range.

     Character     Meaning
     Class Name    
     `alnum'       Alphanumeric characters
     `alpha'       Alphabetic characters
     `blank'       Whitespace characters
     `cntrl'       Control characters
     `digit'       Digit characters
     `graph'       Graphic characters
     `lower'       Lowercase alphabetic characters
     `print'       Graphic or space characters
     `punct'       Punctuation characters
     `space'       Space, tab, newline, and carriage return
     `upper'       Uppercase alphabetic characters
     `xdigit'      Hexadecimal digit characters

          mysql> SELECT 'justalnums' REGEXP '[[:alnum:]]+';       -> 1
          mysql> SELECT '!!' REGEXP '[[:alnum:]]+';               -> 0

   * `[[:<:]]', `[[:>:]]'

     These markers stand for word boundaries. They match the beginning
     and end of words, respectively. A word is a sequence of word
     characters that is not preceded by or followed by word characters.
     A word character is an alphanumeric character in the `alnum' class
     or an underscore (`_').

          mysql> SELECT 'a word a' REGEXP '[[:<:]]word[[:>:]]';   -> 1
          mysql> SELECT 'a xword a' REGEXP '[[:<:]]word[[:>:]]';  -> 0

To use a literal instance of a special character in a regular
expression, precede it by two backslash (\) characters. The MySQL
parser interprets one of the backslashes, and the regular expression
library interprets the other. For example, to match the string `1+2'
that contains the special `+' character, only the last of the following
regular expressions is the correct one:

     mysql> SELECT '1+2' REGEXP '1+2';                       -> 0
     mysql> SELECT '1+2' REGEXP '1\+2';                      -> 0
     mysql> SELECT '1+2' REGEXP '1\\+2';                     -> 1


File: manual.info,  Node: numeric-functions,  Next: date-and-time-functions,  Prev: string-functions,  Up: functions

12.6 Numeric Functions and Operators
====================================

* Menu:

* arithmetic-functions::         Arithmetic Operators
* mathematical-functions::       Mathematical Functions

*Numeric Functions and Operators*

Name                          Description
`ABS()'                       Return the absolute value
`ACOS()'                      Return the arc cosine
`ASIN()'                      Return the arc sine
`ATAN2()', `ATAN()'           Return the arc tangent of the two arguments
`ATAN()'                      Return the arc tangent
`CEIL()'                      Return the smallest integer value not less
                              than  the argument
`CEILING()'                   Return the smallest integer value not less
                              than  the argument
`CONV()'                      Convert numbers between different number
                              bases
`COS()'                       Return the cosine
`COT()'                       Return the cotangent
`CRC32()'                     Compute a cyclic redundancy check value
`DEGREES()'                   Convert radians to degrees
`DIV'                         Integer division
`/'                           Division operator
`EXP()'                       Raise to the power of
`FLOOR()'                     Return the largest integer value not
                              greater than  the argument
`LN()'                        Return the natural logarithm of the
                              argument
`LOG10()'                     Return the base-10 logarithm of the
                              argument
`LOG2()'                      Return the base-2 logarithm of the argument
`LOG()'                       Return the natural logarithm of the first
                              argument
`-'                           Minus operator
`MOD()'                       Return the remainder
`% or MOD'                    Modulo operator
`OCT()'                       Return an octal representation of a
                              decimal  number
`PI()'                        Return the value of pi
`+'                           Addition operator
`POW()'                       Return the argument raised to the
                              specified power
`POWER()'                     Return the argument raised to the
                              specified power
`RADIANS()'                   Return argument converted to radians
`RAND()'                      Return a random floating-point value
`ROUND()'                     Round the argument
`SIGN()'                      Return the sign of the argument
`SIN()'                       Return the sine of the argument
`SQRT()'                      Return the square root of the argument
`TAN()'                       Return the tangent of the argument
`*'                           Multiplication operator
`TRUNCATE()'                  Truncate to specified number of decimal
                              places
`-'                           Change the sign of the argument


File: manual.info,  Node: arithmetic-functions,  Next: mathematical-functions,  Prev: numeric-functions,  Up: numeric-functions

12.6.1 Arithmetic Operators
---------------------------

*Arithmetic Operators*

Name                          Description
`DIV'                         Integer division
`/'                           Division operator
`-'                           Minus operator
`% or MOD'                    Modulo operator
`+'                           Addition operator
`*'                           Multiplication operator
`-'                           Change the sign of the argument

The usual arithmetic operators are available. The result is determined
according to the following rules:

   * In the case of `-', `+', and `*', the result is calculated with
     *Note `BIGINT': numeric-types.  (64-bit) precision if both
     operands are integers.

   * If both operands are integers and any of them are unsigned, the
     result is an unsigned integer. For subtraction, if the
     `NO_UNSIGNED_SUBTRACTION' SQL mode is enabled, the result is
     signed even if any operand is unsigned.

   * If any of the operands of a `+', `-', `/', `*', `%' is a real or
     string value, the precision of the result is the precision of the
     operand with the maximum precision.

   * In division performed with `/', the scale of the result when using
     two exact-value operands is the scale of the first operand plus
     the value of the `div_precision_increment' system variable (which
     is 4 by default). For example, the result of the expression `5.05
     / 0.014' has a scale of six decimal places (`360.714286').

These rules are applied for each operation, such that nested
calculations imply the precision of each component. Hence, `(14620 /
9432456) / (24250 / 9432456)', resolves first to `(0.0014) / (0.0026)',
with the final result having 8 decimal places (`0.60288653').

Because of these rules and the way they are applied, care should be
taken to ensure that components and subcomponents of a calculation use
the appropriate level of precision. See *Note cast-functions::.

For information about handling of overflow in numeric expression
evaluation, see *Note out-of-range-and-overflow::.

Arithmetic operators apply to numbers. For other types of values,
alternative operations may be available. For example, to add date
values, use `DATE_ADD()'; see *Note date-and-time-functions::.

   *  `+'

     Addition:

          mysql> SELECT 3+5;
                  -> 8

   *  `-'

     Subtraction:

          mysql> SELECT 3-5;
                  -> -2

   *  `-'

     Unary minus. This operator changes the sign of the operand.

          mysql> SELECT - 2;
                  -> -2

     *Note*:

     If this operator is used with a *Note `BIGINT': numeric-types, the
     return value is also a *Note `BIGINT': numeric-types. This means
     that you should avoid using `-' on integers that may have the
     value of -2^63.

   *  `*'

     Multiplication:

          mysql> SELECT 3*5;
                  -> 15
          mysql> SELECT 18014398509481984*18014398509481984.0;
                  -> 324518553658426726783156020576256.0

   *  `/'

     Division:

          mysql> SELECT 3/5;
                  -> 0.60

     Division by zero produces a `NULL' result:

          mysql> SELECT 102/(1-1);
                  -> NULL

     A division is calculated with *Note `BIGINT': numeric-types.
     arithmetic only if performed in a context where its result is
     converted to an integer.

   *  `DIV'

     Integer division. Similar to `FLOOR()', but is safe with *Note
     `BIGINT': numeric-types. values. Incorrect results may occur for
     noninteger operands that exceed *Note `BIGINT': numeric-types.
     range.

          mysql> SELECT 5 DIV 2;
                  -> 2

   *  `N % M', `N MOD M'

     Modulo operation. Returns the remainder of N divided by M. For
     more information, see the description for the `MOD()' function in
     *Note mathematical-functions::.


File: manual.info,  Node: mathematical-functions,  Prev: arithmetic-functions,  Up: numeric-functions

12.6.2 Mathematical Functions
-----------------------------

*Mathematical Functions*

Name                          Description
`ABS()'                       Return the absolute value
`ACOS()'                      Return the arc cosine
`ASIN()'                      Return the arc sine
`ATAN2()', `ATAN()'           Return the arc tangent of the two arguments
`ATAN()'                      Return the arc tangent
`CEIL()'                      Return the smallest integer value not less
                              than  the argument
`CEILING()'                   Return the smallest integer value not less
                              than  the argument
`CONV()'                      Convert numbers between different number
                              bases
`COS()'                       Return the cosine
`COT()'                       Return the cotangent
`CRC32()'                     Compute a cyclic redundancy check value
`DEGREES()'                   Convert radians to degrees
`EXP()'                       Raise to the power of
`FLOOR()'                     Return the largest integer value not
                              greater than  the argument
`LN()'                        Return the natural logarithm of the
                              argument
`LOG10()'                     Return the base-10 logarithm of the
                              argument
`LOG2()'                      Return the base-2 logarithm of the argument
`LOG()'                       Return the natural logarithm of the first
                              argument
`MOD()'                       Return the remainder
`OCT()'                       Return an octal representation of a
                              decimal  number
`PI()'                        Return the value of pi
`POW()'                       Return the argument raised to the
                              specified power
`POWER()'                     Return the argument raised to the
                              specified power
`RADIANS()'                   Return argument converted to radians
`RAND()'                      Return a random floating-point value
`ROUND()'                     Round the argument
`SIGN()'                      Return the sign of the argument
`SIN()'                       Return the sine of the argument
`SQRT()'                      Return the square root of the argument
`TAN()'                       Return the tangent of the argument
`TRUNCATE()'                  Truncate to specified number of decimal
                              places

All mathematical functions return `NULL' in the event of an error.

   *  `ABS(X)'

     Returns the absolute value of X.

          mysql> SELECT ABS(2);
                  -> 2
          mysql> SELECT ABS(-32);
                  -> 32

     This function is safe to use with *Note `BIGINT': numeric-types.
     values.

   *  `ACOS(X)'

     Returns the arc cosine of X, that is, the value whose cosine is X.
     Returns `NULL' if X is not in the range `-1' to `1'.

          mysql> SELECT ACOS(1);
                  -> 0
          mysql> SELECT ACOS(1.0001);
                  -> NULL
          mysql> SELECT ACOS(0);
                  -> 1.5707963267949

   *  `ASIN(X)'

     Returns the arc sine of X, that is, the value whose sine is X.
     Returns `NULL' if X is not in the range `-1' to `1'.

          mysql> SELECT ASIN(0.2);
                  -> 0.20135792079033
          mysql> SELECT ASIN('foo');

          +-------------+
          | ASIN('foo') |
          +-------------+
          |           0 |
          +-------------+
          1 row in set, 1 warning (0.00 sec)

          mysql> SHOW WARNINGS;
          +---------+------+-----------------------------------------+
          | Level   | Code | Message                                 |
          +---------+------+-----------------------------------------+
          | Warning | 1292 | Truncated incorrect DOUBLE value: 'foo' |
          +---------+------+-----------------------------------------+

   *  `ATAN(X)'

     Returns the arc tangent of X, that is, the value whose tangent is
     X.

          mysql> SELECT ATAN(2);
                  -> 1.1071487177941
          mysql> SELECT ATAN(-2);
                  -> -1.1071487177941

   *  `ATAN(Y,X)', `ATAN2(Y,X)'

     Returns the arc tangent of the two variables X and Y. It is
     similar to calculating the arc tangent of `Y / X', except that the
     signs of both arguments are used to determine the quadrant of the
     result.

          mysql> SELECT ATAN(-2,2);
                  -> -0.78539816339745
          mysql> SELECT ATAN2(PI(),0);
                  -> 1.5707963267949

   *  `CEIL(X)'

     `CEIL()' is a synonym for `CEILING()'.

   *  `CEILING(X)'

     Returns the smallest integer value not less than X.

          mysql> SELECT CEILING(1.23);
                  -> 2
          mysql> SELECT CEILING(-1.23);
                  -> -1

     For exact-value numeric arguments, the return value has an
     exact-value numeric type. For string or floating-point arguments,
     the return value has a floating-point type.

   *  `CONV(N,FROM_BASE,TO_BASE)'

     Converts numbers between different number bases. Returns a string
     representation of the number N, converted from base FROM_BASE to
     base TO_BASE. Returns `NULL' if any argument is `NULL'. The
     argument N is interpreted as an integer, but may be specified as
     an integer or a string. The minimum base is `2' and the maximum
     base is `36'. If TO_BASE is a negative number, N is regarded as a
     signed number. Otherwise, N is treated as unsigned.  `CONV()'
     works with 64-bit precision.

          mysql> SELECT CONV('a',16,2);
                  -> '1010'
          mysql> SELECT CONV('6E',18,8);
                  -> '172'
          mysql> SELECT CONV(-17,10,-18);
                  -> '-H'
          mysql> SELECT CONV(10+'10'+'10'+0xa,10,10);
                  -> '40'

   *  `COS(X)'

     Returns the cosine of X, where X is given in radians.

          mysql> SELECT COS(PI());
                  -> -1

   *  `COT(X)'

     Returns the cotangent of X.

          mysql> SELECT COT(12);
                  -> -1.5726734063977
          mysql> SELECT COT(0);
                  -> NULL

   *  `CRC32(EXPR)'

     Computes a cyclic redundancy check value and returns a 32-bit
     unsigned value. The result is `NULL' if the argument is `NULL'.
     The argument is expected to be a string and (if possible) is
     treated as one if it is not.

          mysql> SELECT CRC32('MySQL');
                  -> 3259397556
          mysql> SELECT CRC32('mysql');
                  -> 2501908538

   *  `DEGREES(X)'

     Returns the argument X, converted from radians to degrees.

          mysql> SELECT DEGREES(PI());
                  -> 180
          mysql> SELECT DEGREES(PI() / 2);
                  -> 90

   *  `EXP(X)'

     Returns the value of _e_ (the base of natural logarithms) raised
     to the power of X. The inverse of this function is `LOG()' (using
     a single argumentonly) or `LN()'.

          mysql> SELECT EXP(2);
                  -> 7.3890560989307
          mysql> SELECT EXP(-2);
                  -> 0.13533528323661
          mysql> SELECT EXP(0);
                  -> 1

   *  `FLOOR(X)'

     Returns the largest integer value not greater than X.

          mysql> SELECT FLOOR(1.23);
                  -> 1
          mysql> SELECT FLOOR(-1.23);
                  -> -2

     For exact-value numeric arguments, the return value has an
     exact-value numeric type. For string or floating-point arguments,
     the return value has a floating-point type.

   * `FORMAT(X,D)'

     Formats the number X to a format like `'#,###,###.##'', rounded to
     D decimal places, and returns the result as a string. For details,
     see *Note string-functions::.

   * `HEX(N_or_S)'

     This function can be used to obtain a hexadecimal representation
     of a decimal number or a string; the manner in which it does so
     varies according to the argument's type. See this function's
     description in *Note string-functions::, for details.

   *  `LN(X)'

     Returns the natural logarithm of X; that is, the base-_e_
     logarithm of X. If X is less than or equal to 0, then `NULL' is
     returned.

          mysql> SELECT LN(2);
                  -> 0.69314718055995
          mysql> SELECT LN(-2);
                  -> NULL

     This function is synonymous with `LOG(X)'.  The inverse of this
     function is the `EXP()' function.

   *  `LOG(X)', `LOG(B,X)'

     If called with one parameter, this function returns the natural
     logarithm of X. If X is less than or equal to 0, then `NULL' is
     returned.

     The inverse of this function (when called with a single argument)
     is the `EXP()' function.

          mysql> SELECT LOG(2);
                  -> 0.69314718055995
          mysql> SELECT LOG(-2);
                  -> NULL

     If called with two parameters, this function returns the logarithm
     of X to the base B. If X is less than or equal to 0, or if B is
     less than or equal to 1, then `NULL' is returned.

          mysql> SELECT LOG(2,65536);
                  -> 16
          mysql> SELECT LOG(10,100);
                  -> 2
          mysql> SELECT LOG(1,100);
                  -> NULL

     `LOG(B,X)' is equivalent to `LOG(X) / LOG(B)'.

   *  `LOG2(X)'

     Returns the base-2 logarithm of `X'.

          mysql> SELECT LOG2(65536);
                  -> 16
          mysql> SELECT LOG2(-100);
                  -> NULL

     `LOG2()' is useful for finding out how many bits a number requires
     for storage. This function is equivalent to the expression `LOG(X)
     / LOG(2)'.

   *  `LOG10(X)'

     Returns the base-10 logarithm of X.

          mysql> SELECT LOG10(2);
                  -> 0.30102999566398
          mysql> SELECT LOG10(100);
                  -> 2
          mysql> SELECT LOG10(-100);
                  -> NULL

     `LOG10(X)' is equivalent to `LOG(10,X)'.

   *  `MOD(N,M)', `N % M', `N MOD M'

     Modulo operation. Returns the remainder of N divided by M.

          mysql> SELECT MOD(234, 10);
                  -> 4
          mysql> SELECT 253 % 7;
                  -> 1
          mysql> SELECT MOD(29,9);
                  -> 2
          mysql> SELECT 29 MOD 9;
                  -> 2

     This function is safe to use with *Note `BIGINT': numeric-types.
     values.

     `MOD()' also works on values that have a fractional part and
     returns the exact remainder after division:

          mysql> SELECT MOD(34.5,3);
                  -> 1.5

     `MOD(N,0)' returns `NULL'.

   *  `PI()'

     Returns the value of π (pi). The default number of decimal places
     displayed is seven, but MySQL uses the full double-precision value
     internally.

          mysql> SELECT PI();
                  -> 3.141593
          mysql> SELECT PI()+0.000000000000000000;
                  -> 3.141592653589793116

   *  `POW(X,Y)'

     Returns the value of X raised to the power of Y.

          mysql> SELECT POW(2,2);
                  -> 4
          mysql> SELECT POW(2,-2);
                  -> 0.25

   *  `POWER(X,Y)'

     This is a synonym for `POW()'.

   *  `RADIANS(X)'

     Returns the argument X, converted from degrees to radians. (Note
     that π radians equals 180 degrees.)

          mysql> SELECT RADIANS(90);
                  -> 1.5707963267949

   *  `RAND()', `RAND(N)'

     Returns a random floating-point value V in the range `0' <= V <
     `1.0'. If a constant integer argument N is specified, it is used
     as the seed value, which produces a repeatable sequence of column
     values. In the following example, note that the sequences of
     values produced by `RAND(3)' is the same both places where it
     occurs.


          mysql> CREATE TABLE t (i INT);
          Query OK, 0 rows affected (0.42 sec)

          mysql> INSERT INTO t VALUES(1),(2),(3);
          Query OK, 3 rows affected (0.00 sec)
          Records: 3  Duplicates: 0  Warnings: 0

          mysql> SELECT i, RAND() FROM t;
          +------+------------------+
          | i    | RAND()           |
          +------+------------------+
          |    1 | 0.61914388706828 |
          |    2 | 0.93845168309142 |
          |    3 | 0.83482678498591 |
          +------+------------------+
          3 rows in set (0.00 sec)

          mysql> SELECT i, RAND(3) FROM t;
          +------+------------------+
          | i    | RAND(3)          |
          +------+------------------+
          |    1 | 0.90576975597606 |
          |    2 | 0.37307905813035 |
          |    3 | 0.14808605345719 |
          +------+------------------+
          3 rows in set (0.00 sec)

          mysql> SELECT i, RAND() FROM t;
          +------+------------------+
          | i    | RAND()           |
          +------+------------------+
          |    1 | 0.35877890638893 |
          |    2 | 0.28941420772058 |
          |    3 | 0.37073435016976 |
          +------+------------------+
          3 rows in set (0.00 sec)

          mysql> SELECT i, RAND(3) FROM t;
          +------+------------------+
          | i    | RAND(3)          |
          +------+------------------+
          |    1 | 0.90576975597606 |
          |    2 | 0.37307905813035 |
          |    3 | 0.14808605345719 |
          +------+------------------+
          3 rows in set (0.01 sec)

     The effect of using a nonconstant argument is undefined. As of
     MySQL 5.0.13, nonconstant arguments are not permitted.

     To obtain a random integer R in the range I <= R < J, use the
     expression `FLOOR(I + RAND() * (J' - `I))'.  For example, to
     obtain a random integer in the range the range `7' <= R < `12', you
     could use the following statement:

          SELECT FLOOR(7 + (RAND() * 5));

     `RAND()' in a `WHERE' clause is re-evaluated every time the
     `WHERE' is executed.

     You cannot use a column with `RAND()' values in an `ORDER BY'
     clause, because `ORDER BY' would evaluate the column multiple
     times.  However, you can retrieve rows in random order like this:

          mysql> SELECT * FROM TBL_NAME ORDER BY RAND();

     `ORDER BY RAND()' combined with `LIMIT' is useful for selecting a
     random sample from a set of rows:

          mysql> SELECT * FROM table1, table2 WHERE a=b AND c<d -> ORDER BY RAND() LIMIT 1000;

     `RAND()' is not meant to be a perfect random generator. It is a
     fast way to generate random numbers on demand that is portable
     between platforms for the same MySQL version.

   *  `ROUND(X)', `ROUND(X,D)'

     Rounds the argument X to D decimal places. The rounding algorithm
     depends on the data type of X. D defaults to 0 if not specified. D
     can be negative to cause D digits left of the decimal point of the
     value X to become zero.

          mysql> SELECT ROUND(-1.23);
                  -> -1
          mysql> SELECT ROUND(-1.58);
                  -> -2
          mysql> SELECT ROUND(1.58);
                  -> 2
          mysql> SELECT ROUND(1.298, 1);
                  -> 1.3
          mysql> SELECT ROUND(1.298, 0);
                  -> 1
          mysql> SELECT ROUND(23.298, -1);
                  -> 20

     The return type is the same type as that of the first argument
     (assuming that it is integer, double, or decimal).  This means
     that for an integer argument, the result is an integer (no decimal
     places):

          mysql> SELECT ROUND(150.000,2), ROUND(150,2);
          +------------------+--------------+
          | ROUND(150.000,2) | ROUND(150,2) |
          +------------------+--------------+
          |           150.00 |          150 |
          +------------------+--------------+

     Before MySQL 5.0.3, the behavior of `ROUND()' when the argument is
     halfway between two integers depends on the C library
     implementation. Different implementations round to the nearest
     even number, always up, always down, or always toward zero. If you
     need one kind of rounding, you should use a well-defined function
     such as `TRUNCATE()' or `FLOOR()' instead.

     As of MySQL 5.0.3, `ROUND()' uses the following rules depending on
     the type of the first argument:

        * For exact-value numbers, `ROUND()' uses the `round half up'
          or `round toward nearest' rule: A value with a fractional
          part of .5 or greater is rounded up to the next integer if
          positive or down to the next integer if negative. (In other
          words, it is rounded away from zero.) A value with a
          fractional part less than .5 is rounded down to the next
          integer if positive or up to the next integer if negative.

        * For approximate-value numbers, the result depends on the C
          library. On many systems, this means that `ROUND()' uses the
          "round to nearest even" rule: A value with any fractional part
          is rounded to the nearest even integer.

     The following example shows how rounding differs for exact and
     approximate values:

          mysql> SELECT ROUND(2.5), ROUND(25E-1);
          +------------+--------------+
          | ROUND(2.5) | ROUND(25E-1) |
          +------------+--------------+
          | 3          |            2 |
          +------------+--------------+

     For more information, see *Note precision-math::.

   *  `SIGN(X)'

     Returns the sign of the argument as `-1', `0', or `1', depending on
     whether X is negative, zero, or positive.

          mysql> SELECT SIGN(-32);
                  -> -1
          mysql> SELECT SIGN(0);
                  -> 0
          mysql> SELECT SIGN(234);
                  -> 1

   *  `SIN(X)'

     Returns the sine of X, where X is given in radians.

          mysql> SELECT SIN(PI());
                  -> 1.2246063538224e-16
          mysql> SELECT ROUND(SIN(PI()));
                  -> 0

   *  `SQRT(X)'

     Returns the square root of a nonnegative number X.

          mysql> SELECT SQRT(4);
                  -> 2
          mysql> SELECT SQRT(20);
                  -> 4.4721359549996
          mysql> SELECT SQRT(-16);
                  -> NULL

   *  `TAN(X)'

     Returns the tangent of X, where X is given in radians.

          mysql> SELECT TAN(PI());
                  -> -1.2246063538224e-16
          mysql> SELECT TAN(PI()+1);
                  -> 1.5574077246549

   *  `TRUNCATE(X,D)'

     Returns the number X, truncated to D decimal places. If D is `0',
     the result has no decimal point or fractional part.  D can be
     negative to cause D digits left of the decimal point of the value
     X to become zero.

          mysql> SELECT TRUNCATE(1.223,1);
                  -> 1.2
          mysql> SELECT TRUNCATE(1.999,1);
                  -> 1.9
          mysql> SELECT TRUNCATE(1.999,0);
                  -> 1
          mysql> SELECT TRUNCATE(-1.999,1);
                  -> -1.9
          mysql> SELECT TRUNCATE(122,-2);
                 -> 100
          mysql> SELECT TRUNCATE(10.28*100,0);
                 -> 1028

     All numbers are rounded toward zero.


File: manual.info,  Node: date-and-time-functions,  Next: mysql-calendar,  Prev: numeric-functions,  Up: functions

12.7 Date and Time Functions
============================

This section describes the functions that can be used to manipulate
temporal values. See *Note date-and-time-types::, for a description of
the range of values each date and time type has and the valid formats
in which values may be specified.

*Date/Time Functions*

Name                          Description
`ADDDATE()'                   Add time values (intervals) to a date value
`ADDTIME()'                   Add time
`CONVERT_TZ()'                Convert from one timezone to another
`CURDATE()'                   Return the current date
`CURRENT_DATE()',             Synonyms for CURDATE()
`CURRENT_DATE'                
`CURRENT_TIME()',             Synonyms for CURTIME()
`CURRENT_TIME'                
`CURRENT_TIMESTAMP()',        Synonyms for NOW()
`CURRENT_TIMESTAMP'           
`CURTIME()'                   Return the current time
`DATE_ADD()'                  Add time values (intervals) to a date value
`DATE_FORMAT()'               Format date as specified
`DATE_SUB()'                  Subtract a time value (interval) from a
                              date
`DATE()'                      Extract the date part of a date or
                              datetime expression
`DATEDIFF()'                  Subtract two dates
`DAY()'                       Synonym for DAYOFMONTH()
`DAYNAME()'                   Return the name of the weekday
`DAYOFMONTH()'                Return the day of the month (0-31)
`DAYOFWEEK()'                 Return the weekday index of the argument
`DAYOFYEAR()'                 Return the day of the year (1-366)
`EXTRACT()'                   Extract part of a date
`FROM_DAYS()'                 Convert a day number to a date
`FROM_UNIXTIME()'             Format UNIX timestamp as a date
`GET_FORMAT()'                Return a date format string
`HOUR()'                      Extract the hour
`LAST_DAY'                    Return the last day of the month for the
                              argument
`LOCALTIME()', `LOCALTIME'    Synonym for NOW()
`LOCALTIMESTAMP',             Synonym for NOW()
`LOCALTIMESTAMP()'            
`MAKEDATE()'                  Create a date from the year and day of year
`MAKETIME'                    MAKETIME()
`MICROSECOND()'               Return the microseconds from argument
`MINUTE()'                    Return the minute from the argument
`MONTH()'                     Return the month from the date passed
`MONTHNAME()'                 Return the name of the month
`NOW()'                       Return the current date and time
`PERIOD_ADD()'                Add a period to a year-month
`PERIOD_DIFF()'               Return the number of months between periods
`QUARTER()'                   Return the quarter from a date argument
`SEC_TO_TIME()'               Converts seconds to 'HH:MM:SS' format
`SECOND()'                    Return the second (0-59)
`STR_TO_DATE()'               Convert a string to a date
`SUBDATE()'                   A synonym for DATE_SUB() when invoked with
                              three arguments
`SUBTIME()'                   Subtract times
`SYSDATE()'                   Return the time at which the function
                              executes
`TIME_FORMAT()'               Format as time
`TIME_TO_SEC()'               Return the argument converted to seconds
`TIME()'                      Extract the time portion of the expression
                              passed
`TIMEDIFF()'                  Subtract time
`TIMESTAMP()'                 With a single argument, this function
                              returns the date or  datetime expression;
                              with two arguments, the sum of the
                              arguments
`TIMESTAMPADD()'              Add an interval to a datetime expression
`TIMESTAMPDIFF()'             Subtract an interval from a datetime
                              expression
`TO_DAYS()'                   Return the date argument converted to days
`UNIX_TIMESTAMP()'            Return a UNIX timestamp
`UTC_DATE()'                  Return the current UTC date
`UTC_TIME()'                  Return the current UTC time
`UTC_TIMESTAMP()'             Return the current UTC date and time
`WEEK()'                      Return the week number
`WEEKDAY()'                   Return the weekday index
`WEEKOFYEAR()'                Return the calendar week of the date (0-53)
`YEAR()'                      Return the year
`YEARWEEK()'                  Return the year and week

Here is an example that uses date functions. The following query
selects all rows with a DATE_COL value from within the last 30 days:

     mysql> SELECT SOMETHING FROM TBL_NAME
         -> WHERE DATE_SUB(CURDATE(),INTERVAL 30 DAY) <= DATE_COL;

The query also selects rows with dates that lie in the future.

Functions that expect date values usually accept datetime values and
ignore the time part. Functions that expect time values usually accept
datetime values and ignore the date part.

Functions that return the current date or time each are evaluated only
once per query at the start of query execution. This means that
multiple references to a function such as `NOW()' within a single query
always produce the same result. (For our purposes, a single query also
includes a call to a stored program (stored routine or trigger) and all
subprograms called by that program.) This principle also applies to
`CURDATE()', `CURTIME()', `UTC_DATE()', `UTC_TIME()',
`UTC_TIMESTAMP()', and to any of their synonyms.

The `CURRENT_TIMESTAMP()', `CURRENT_TIME()', `CURRENT_DATE()', and
`FROM_UNIXTIME()' functions return values in the connection's current
time zone, which is available as the value of the `time_zone' system
variable. In addition, `UNIX_TIMESTAMP()' assumes that its argument is
a datetime value in the current time zone. See *Note
time-zone-support::.

Some date functions can be used with `zero' dates or incomplete dates
such as `'2001-11-00'', whereas others cannot. Functions that extract
parts of dates typically work with incomplete dates and thus can return
0 when you might otherwise expect a nonzero value. For example:

     mysql> SELECT DAYOFMONTH('2001-11-00'), MONTH('2005-00-00');
             -> 0, 0

Other functions expect complete dates and return `NULL' for incomplete
dates. These include functions that perform date arithmetic or that map
parts of dates to names. For example:

     mysql> SELECT DATE_ADD('2006-05-00',INTERVAL 1 DAY);
             -> NULL
     mysql> SELECT DAYNAME('2006-05-00');
             -> NULL

   *  `ADDDATE(DATE,INTERVAL EXPR UNIT)', `ADDDATE(EXPR,DAYS)'

     When invoked with the `INTERVAL' form of the second argument,
     `ADDDATE()' is a synonym for `DATE_ADD()'. The related function
     `SUBDATE()' is a synonym for `DATE_SUB()'. For information on the
     `INTERVAL' UNIT argument, see the discussion for `DATE_ADD()'.

          mysql> SELECT DATE_ADD('2008-01-02', INTERVAL 31 DAY);
                  -> '2008-02-02'
          mysql> SELECT ADDDATE('2008-01-02', INTERVAL 31 DAY);
                  -> '2008-02-02'

     When invoked with the DAYS form of the second argument, MySQL
     treats it as an integer number of days to be added to EXPR.

          mysql> SELECT ADDDATE('2008-01-02', 31);
                  -> '2008-02-02'

   *  `ADDTIME(EXPR1,EXPR2)'

     `ADDTIME()' adds EXPR2 to EXPR1 and returns the result.  EXPR1 is
     a time or datetime expression, and EXPR2 is a time expression.

          mysql> SELECT ADDTIME('2007-12-31 23:59:59.999999', '1 1:1:1.000002');
                  -> '2008-01-02 01:01:01.000001'
          mysql> SELECT ADDTIME('01:00:00.999999', '02:00:00.999998');
                  -> '03:00:01.999997'

   *  `CONVERT_TZ(DT,FROM_TZ,TO_TZ)'

     `CONVERT_TZ()' converts a datetime value DT from the time zone
     given by FROM_TZ to the time zone given by TO_TZ and returns the
     resulting value. Time zones are specified as described in *Note
     time-zone-support::. This function returns `NULL' if the arguments
     are invalid.

     If the value falls out of the supported range of the *Note
     `TIMESTAMP': datetime. type when converted from FROM_TZ to UTC, no
     conversion occurs. The *Note `TIMESTAMP': datetime. range is
     described in *Note date-and-time-type-overview::.

          mysql> SELECT CONVERT_TZ('2004-01-01 12:00:00','GMT','MET');
                  -> '2004-01-01 13:00:00'
          mysql> SELECT CONVERT_TZ('2004-01-01 12:00:00','+00:00','+10:00');
                  -> '2004-01-01 22:00:00'

     *Note*:

     To use named time zones such as `'MET'' or `'Europe/Moscow'', the
     time zone tables must be properly set up. See *Note
     time-zone-support::, for instructions.

     If you intend to use `CONVERT_TZ()' while other tables are locked
     with *Note `LOCK TABLES': lock-tables, you must also lock the
     `mysql.time_zone_name' table.

   *  `CURDATE()'

     Returns the current date as a value in `'YYYY-MM-DD'' or `YYYYMMDD'
     format, depending on whether the function is used in a string or
     numeric context.

          mysql> SELECT CURDATE();
                  -> '2008-06-13'
          mysql> SELECT CURDATE() + 0;
                  -> 20080613

   *  `CURRENT_DATE', `CURRENT_DATE()'

     `CURRENT_DATE' and `CURRENT_DATE()' are synonyms for `CURDATE()'.

   *  `CURTIME()'

     Returns the current time as a value in `'HH:MM:SS'' or
     `HHMMSS.uuuuuu' format, depending on whether the function is used
     in a string or numeric context. The value is expressed in the
     current time zone.

          mysql> SELECT CURTIME();
                  -> '23:50:26'
          mysql> SELECT CURTIME() + 0;
                  -> 235026.000000

   *  `CURRENT_TIME', `CURRENT_TIME()'

     `CURRENT_TIME' and `CURRENT_TIME()' are synonyms for `CURTIME()'.

   *  `CURRENT_TIMESTAMP', `CURRENT_TIMESTAMP()'

     `CURRENT_TIMESTAMP' and `CURRENT_TIMESTAMP()' are synonyms for
     `NOW()'.

   *  `DATE(EXPR)'

     Extracts the date part of the date or datetime expression EXPR.

          mysql> SELECT DATE('2003-12-31 01:02:03');
                  -> '2003-12-31'

   *  `DATEDIFF(EXPR1,EXPR2)'

     `DATEDIFF()' returns EXPR1 - EXPR2 expressed as a value in days
     from one date to the other. EXPR1 and EXPR2 are date or
     date-and-time expressions. Only the date parts of the values are
     used in the calculation.

          mysql> SELECT DATEDIFF('2007-12-31 23:59:59','2007-12-30');
                  -> 1
          mysql> SELECT DATEDIFF('2010-11-30 23:59:59','2010-12-31');
                  -> -31

   *  `DATE_ADD(DATE,INTERVAL EXPR UNIT)', `DATE_SUB(DATE,INTERVAL EXPR
     UNIT)'

     These functions perform date arithmetic. The DATE argument
     specifies the starting date or datetime value.  EXPR is an
     expression specifying the interval value to be added or subtracted
     from the starting date. EXPR is a string; it may start with a
     ``-'' for negative intervals. UNIT is a keyword indicating the
     units in which the expression should be interpreted.

     The `INTERVAL' keyword and the UNIT specifier are not case
     sensitive.

     The following table shows the expected form of the EXPR argument
     for each UNIT value.

     UNIT Value                         Expected EXPR Format
     `MICROSECOND'                      `MICROSECONDS'
     `SECOND'                           `SECONDS'
     `MINUTE'                           `MINUTES'
     `HOUR'                             `HOURS'
     `DAY'                              `DAYS'
     `WEEK'                             `WEEKS'
     `MONTH'                            `MONTHS'
     `QUARTER'                          `QUARTERS'
     `YEAR'                             `YEARS'
     `SECOND_MICROSECOND'               `'SECONDS.MICROSECONDS''
     `MINUTE_MICROSECOND'               `'MINUTES:SECONDS.MICROSECONDS''
     `MINUTE_SECOND'                    `'MINUTES:SECONDS''
     `HOUR_MICROSECOND'                 `'HOURS:MINUTES:SECONDS.MICROSECONDS''
     `HOUR_SECOND'                      `'HOURS:MINUTES:SECONDS''
     `HOUR_MINUTE'                      `'HOURS:MINUTES''
     `DAY_MICROSECOND'                  `'DAYS
                                        HOURS:MINUTES:SECONDS.MICROSECONDS''
     `DAY_SECOND'                       `'DAYS HOURS:MINUTES:SECONDS''
     `DAY_MINUTE'                       `'DAYS HOURS:MINUTES''
     `DAY_HOUR'                         `'DAYS HOURS''
     `YEAR_MONTH'                       `'YEARS-MONTHS''

     The values `QUARTER' and `WEEK' are available beginning with MySQL
     5.0.0.

     The return value depends on the arguments:

        * *Note `DATETIME': datetime. if the first argument is a *Note
          `DATETIME': datetime. (or *Note `TIMESTAMP': datetime.)
          value, or if the first argument is a *Note `DATE': datetime.
          and the UNIT value uses `HOURS', `MINUTES', or `SECONDS'.

        * String otherwise.

     To ensure that the result is *Note `DATETIME': datetime, you can
     use `CAST()' to convert the first argument to *Note `DATETIME':
     datetime.

     MySQL permits any punctuation delimiter in the EXPR format. Those
     shown in the table are the suggested delimiters. If the DATE
     argument is a *Note `DATE': datetime. value and your calculations
     involve only `YEAR', `MONTH', and `DAY' parts (that is, no time
     parts), the result is a *Note `DATE': datetime. value. Otherwise,
     the result is a *Note `DATETIME': datetime. value.

     Date arithmetic also can be performed using `INTERVAL' together
     with the `+' or `-' operator:

          `date' + INTERVAL EXPR UNIT
          `date' - INTERVAL EXPR UNIT

     `INTERVAL EXPR UNIT' is permitted on either side of the `+'
     operator if the expression on the other side is a date or datetime
     value.  For the `-' operator, `INTERVAL EXPR UNIT' is permitted
     only on the right side, because it makes no sense to subtract a
     date or datetime value from an interval.

          mysql> SELECT '2008-12-31 23:59:59' + INTERVAL 1 SECOND;
                  -> '2009-01-01 00:00:00'
          mysql> SELECT INTERVAL 1 DAY + '2008-12-31';
                  -> '2009-01-01'
          mysql> SELECT '2005-01-01' - INTERVAL 1 SECOND;
                  -> '2004-12-31 23:59:59'
          mysql> SELECT DATE_ADD('2000-12-31 23:59:59',
              ->                 INTERVAL 1 SECOND);
                  -> '2001-01-01 00:00:00'
          mysql> SELECT DATE_ADD('2010-12-31 23:59:59',
              ->                 INTERVAL 1 DAY);
                  -> '2011-01-01 23:59:59'
          mysql> SELECT DATE_ADD('2100-12-31 23:59:59',
              ->                 INTERVAL '1:1' MINUTE_SECOND);
                  -> '2101-01-01 00:01:00'
          mysql> SELECT DATE_SUB('2005-01-01 00:00:00',
              ->                 INTERVAL '1 1:1:1' DAY_SECOND);
                  -> '2004-12-30 22:58:59'
          mysql> SELECT DATE_ADD('1900-01-01 00:00:00',
              ->                 INTERVAL '-1 10' DAY_HOUR);
                  -> '1899-12-30 14:00:00'
          mysql> SELECT DATE_SUB('1998-01-02', INTERVAL 31 DAY);
                  -> '1997-12-02'
          mysql> SELECT DATE_ADD('1992-12-31 23:59:59.000002',
              ->            INTERVAL '1.999999' SECOND_MICROSECOND);
                  -> '1993-01-01 00:00:01.000001'

     If you specify an interval value that is too short (does not
     include all the interval parts that would be expected from the
     UNIT keyword), MySQL assumes that you have left out the leftmost
     parts of the interval value.  For example, if you specify a UNIT
     of `DAY_SECOND', the value of EXPR is expected to have days,
     hours, minutes, and seconds parts. If you specify a value like
     `'1:10'', MySQL assumes that the days and hours parts are missing
     and the value represents minutes and seconds. In other words,
     `'1:10' DAY_SECOND' is interpreted in such a way that it is
     equivalent to `'1:10' MINUTE_SECOND'. This is analogous to the way
     that MySQL interprets *Note `TIME': time. values as representing
     elapsed time rather than as a time of day.

     Because EXPR is treated as a string, be careful if you specify a
     nonstring value with `INTERVAL'. For example, with an interval
     specifier of `HOUR_MINUTE', `6/4' evaluates to `1.5000' and is
     treated as 1 hour, 5000 minutes:

          mysql> SELECT 6/4;
                  -> 1.5000
          mysql> SELECT DATE_ADD('2009-01-01', INTERVAL 6/4 HOUR_MINUTE);
                  -> '2009-01-04 12:20:00'

     To ensure interpretation of the interval value as you expect, a
     `CAST()' operation may be used.  To treat `6/4' as 1 hour, 5
     minutes, cast it to a *Note `DECIMAL': numeric-types. value with a
     single fractional digit:

          mysql> SELECT CAST(6/4 AS DECIMAL(3,1));
                  -> 1.5
          mysql> SELECT DATE_ADD('1970-01-01 12:00:00',
              ->                 INTERVAL CAST(6/4 AS DECIMAL(3,1)) HOUR_MINUTE);
                  -> '1970-01-01 13:05:00'

     If you add to or subtract from a date value something that
     contains a time part, the result is automatically converted to a
     datetime value:

          mysql> SELECT DATE_ADD('2013-01-01', INTERVAL 1 DAY);
                  -> '2013-01-02'
          mysql> SELECT DATE_ADD('2013-01-01', INTERVAL 1 HOUR);
                  -> '2013-01-01 01:00:00'

     If you add `MONTH', `YEAR_MONTH', or `YEAR' and the resulting date
     has a day that is larger than the maximum day for the new month,
     the day is adjusted to the maximum days in the new month:

          mysql> SELECT DATE_ADD('2009-01-30', INTERVAL 1 MONTH);
                  -> '2009-02-28'

     Date arithmetic operations require complete dates and do not work
     with incomplete dates such as `'2006-07-00'' or badly malformed
     dates:

          mysql> SELECT DATE_ADD('2006-07-00', INTERVAL 1 DAY);
                  -> NULL
          mysql> SELECT '2005-03-32' + INTERVAL 1 MONTH;
                  -> NULL

   *  `DATE_FORMAT(DATE,FORMAT)'

     Formats the DATE value according to the FORMAT string.

     The following specifiers may be used in the FORMAT string. The
     ``%'' character is required before format specifier characters.

     Specifier     Description
     `%a'          Abbreviated weekday name (`Sun'..`Sat')
     `%b'          Abbreviated month name (`Jan'..`Dec')
     `%c'          Month, numeric (`0'..`12')
     `%D'          Day of the month with English suffix (`0th',
                   `1st', `2nd', `3rd', ...)
     `%d'          Day of the month, numeric (`00'..`31')
     `%e'          Day of the month, numeric (`0'..`31')
     `%f'          Microseconds (`000000'..`999999')
     `%H'          Hour (`00'..`23')
     `%h'          Hour (`01'..`12')
     `%I'          Hour (`01'..`12')
     `%i'          Minutes, numeric (`00'..`59')
     `%j'          Day of year (`001'..`366')
     `%k'          Hour (`0'..`23')
     `%l'          Hour (`1'..`12')
     `%M'          Month name (`January'..`December')
     `%m'          Month, numeric (`00'..`12')
     `%p'          `AM' or `PM'
     `%r'          Time, 12-hour (`hh:mm:ss' followed by `AM' or
                   `PM')
     `%S'          Seconds (`00'..`59')
     `%s'          Seconds (`00'..`59')
     `%T'          Time, 24-hour (`hh:mm:ss')
     `%U'          Week (`00'..`53'), where Sunday is the first
                   day of the week
     `%u'          Week (`00'..`53'), where Monday is the first
                   day of the week
     `%V'          Week (`01'..`53'), where Sunday is the first
                   day of the week; used with `%X'
     `%v'          Week (`01'..`53'), where Monday is the first
                   day of the week; used with `%x'
     `%W'          Weekday name (`Sunday'..`Saturday')
     `%w'          Day of the week (`0'=Sunday..`6'=Saturday)
     `%X'          Year for the week where Sunday is the first
                   day of the week, numeric, four digits; used
                   with `%V'
     `%x'          Year for the week, where Monday is the first
                   day of the week, numeric, four digits; used
                   with `%v'
     `%Y'          Year, numeric, four digits
     `%y'          Year, numeric (two digits)
     `%%'          A literal ``%'' character
     `%X'          X, for any `X' not listed above

     Ranges for the month and day specifiers begin with zero due to the
     fact that MySQL permits the storing of incomplete dates such as
     `'2014-00-00''.

     As of MySQL 5.0.25, the language used for day and month names and
     abbreviations is controlled by the value of the `lc_time_names'
     system variable (*Note locale-support::).

     As of MySQL 5.0.36, `DATE_FORMAT()' returns a string with a
     character set and collation given by `character_set_connection' and
     `collation_connection' so that it can return month and weekday
     names containing non-ASCII characters. Before 5.0.36, the return
     value is a binary string.

          mysql> SELECT DATE_FORMAT('2009-10-04 22:23:00', '%W %M %Y');
                  -> 'Sunday October 2009'
          mysql> SELECT DATE_FORMAT('2007-10-04 22:23:00', '%H:%i:%s');
                  -> '22:23:00'
          mysql> SELECT DATE_FORMAT('1900-10-04 22:23:00',
              ->                 '%D %y %a %d %m %b %j');
                  -> '4th 00 Thu 04 10 Oct 277'
          mysql> SELECT DATE_FORMAT('1997-10-04 22:23:00',
              ->                 '%H %k %I %r %T %S %w');
                  -> '22 22 10 10:23:00 PM 22:23:00 00 6'
          mysql> SELECT DATE_FORMAT('1999-01-01', '%X %V');
                  -> '1998 52'
          mysql> SELECT DATE_FORMAT('2006-06-00', '%d');
                  -> '00'

   *  `DATE_SUB(DATE,INTERVAL EXPR UNIT)'

     See the description for `DATE_ADD()'.

   *  `DAY(DATE)'

     `DAY()' is a synonym for `DAYOFMONTH()'.

   *  `DAYNAME(DATE)'

     Returns the name of the weekday for DATE. As of MySQL 5.0.25, the
     language used for the name is controlled by the value of the
     `lc_time_names' system variable (*Note locale-support::).

          mysql> SELECT DAYNAME('2007-02-03');
                  -> 'Saturday'

   *  `DAYOFMONTH(DATE)'

     Returns the day of the month for DATE, in the range `1' to `31', or
     `0' for dates such as `'0000-00-00'' or `'2008-00-00'' that have a
     zero day part.

          mysql> SELECT DAYOFMONTH('2007-02-03');
                  -> 3

   *  `DAYOFWEEK(DATE)'

     Returns the weekday index for DATE (`1' = Sunday, `2' = Monday,
     ..., `7' = Saturday). These index values correspond to the ODBC
     standard.

          mysql> SELECT DAYOFWEEK('2007-02-03');
                  -> 7

   *  `DAYOFYEAR(DATE)'

     Returns the day of the year for DATE, in the range `1' to `366'.

          mysql> SELECT DAYOFYEAR('2007-02-03');
                  -> 34

   *  `EXTRACT(UNIT FROM DATE)'

     The `EXTRACT()' function uses the same kinds of unit specifiers as
     `DATE_ADD()' or `DATE_SUB()', but extracts parts from the date
     rather than performing date arithmetic.

          mysql> SELECT EXTRACT(YEAR FROM '2009-07-02');
                 -> 2009
          mysql> SELECT EXTRACT(YEAR_MONTH FROM '2009-07-02 01:02:03');
                 -> 200907
          mysql> SELECT EXTRACT(DAY_MINUTE FROM '2009-07-02 01:02:03');
                 -> 20102
          mysql> SELECT EXTRACT(MICROSECOND
              ->                FROM '2003-01-02 10:30:00.000123');
                  -> 123

   *  `FROM_DAYS(N)'

     Given a day number N, returns a *Note `DATE': datetime. value.

          mysql> SELECT FROM_DAYS(730669);
                  -> '2007-07-03'

     Use `FROM_DAYS()' with caution on old dates. It is not intended
     for use with values that precede the advent of the Gregorian
     calendar (1582). See *Note mysql-calendar::.

   *  `FROM_UNIXTIME(UNIX_TIMESTAMP)',
     `FROM_UNIXTIME(UNIX_TIMESTAMP,FORMAT)'

     Returns a representation of the UNIX_TIMESTAMP argument as a value
     in `'YYYY-MM-DD HH:MM:SS'' or `YYYYMMDDHHMMSS.uuuuuu' format,
     depending on whether the function is used in a string or numeric
     context.  The value is expressed in the current time zone.
     UNIX_TIMESTAMP is an internal timestamp value such as is produced
     by the `UNIX_TIMESTAMP()' function.

     If FORMAT is given, the result is formatted according to the FORMAT
     string, which is used the same way as listed in the entry for the
     `DATE_FORMAT()' function.

          mysql> SELECT FROM_UNIXTIME(1196440219);
                  -> '2007-11-30 10:30:19'
          mysql> SELECT FROM_UNIXTIME(1196440219) + 0;
                  -> 20071130103019.000000
          mysql> SELECT FROM_UNIXTIME(UNIX_TIMESTAMP(),
              ->                      '%Y %D %M %h:%i:%s %x');
                  -> '2007 30th November 10:30:59 2007'

     Note: If you use `UNIX_TIMESTAMP()' and `FROM_UNIXTIME()' to
     convert between *Note `TIMESTAMP': datetime. values and Unix
     timestamp values, the conversion is lossy because the mapping is
     not one-to-one in both directions. For details, see the
     description of the `UNIX_TIMESTAMP()' function.

   *  `GET_FORMAT({DATE|TIME|DATETIME},
     {'EUR'|'USA'|'JIS'|'ISO'|'INTERNAL'})'

     Returns a format string. This function is useful in combination
     with the `DATE_FORMAT()' and the `STR_TO_DATE()' functions.

     The possible values for the first and second arguments result in
     several possible format strings (for the specifiers used, see the
     table in the `DATE_FORMAT()' function description). ISO format
     refers to ISO 9075, not ISO 8601.

     Function Call                            Result
     `GET_FORMAT(DATE,'USA')'                 `'%m.%d.%Y''
     `GET_FORMAT(DATE,'JIS')'                 `'%Y-%m-%d''
     `GET_FORMAT(DATE,'ISO')'                 `'%Y-%m-%d''
     `GET_FORMAT(DATE,'EUR')'                 `'%d.%m.%Y''
     `GET_FORMAT(DATE,'INTERNAL')'            `'%Y%m%d''
     `GET_FORMAT(DATETIME,'USA')'             `'%Y-%m-%d %H.%i.%s''
     `GET_FORMAT(DATETIME,'JIS')'             `'%Y-%m-%d %H:%i:%s''
     `GET_FORMAT(DATETIME,'ISO')'             `'%Y-%m-%d %H:%i:%s''
     `GET_FORMAT(DATETIME,'EUR')'             `'%Y-%m-%d %H.%i.%s''
     `GET_FORMAT(DATETIME,'INTERNAL')'        `'%Y%m%d%H%i%s''
     `GET_FORMAT(TIME,'USA')'                 `'%h:%i:%s %p''
     `GET_FORMAT(TIME,'JIS')'                 `'%H:%i:%s''
     `GET_FORMAT(TIME,'ISO')'                 `'%H:%i:%s''
     `GET_FORMAT(TIME,'EUR')'                 `'%H.%i.%s''
     `GET_FORMAT(TIME,'INTERNAL')'            `'%H%i%s''

     *Note `TIMESTAMP': datetime. can also be used as the first
     argument to `GET_FORMAT()', in which case the function returns the
     same values as for *Note `DATETIME': datetime.

          mysql> SELECT DATE_FORMAT('2003-10-03',GET_FORMAT(DATE,'EUR'));
                  -> '03.10.2003'
          mysql> SELECT STR_TO_DATE('10.31.2003',GET_FORMAT(DATE,'USA'));
                  -> '2003-10-31'

   *  `HOUR(TIME)'

     Returns the hour for TIME. The range of the return value is `0' to
     `23' for time-of-day values. However, the range of *Note `TIME':
     time. values actually is much larger, so `HOUR' can return values
     greater than `23'.

          mysql> SELECT HOUR('10:05:03');
                  -> 10
          mysql> SELECT HOUR('272:59:59');
                  -> 272

   *  `LAST_DAY(DATE)'

     Takes a date or datetime value and returns the corresponding value
     for the last day of the month. Returns `NULL' if the argument is
     invalid.

          mysql> SELECT LAST_DAY('2003-02-05');
                  -> '2003-02-28'
          mysql> SELECT LAST_DAY('2004-02-05');
                  -> '2004-02-29'
          mysql> SELECT LAST_DAY('2004-01-01 01:01:01');
                  -> '2004-01-31'
          mysql> SELECT LAST_DAY('2003-03-32');
                  -> NULL

   *  `LOCALTIME', `LOCALTIME()'

     `LOCALTIME' and `LOCALTIME()' are synonyms for `NOW()'.

   *  `LOCALTIMESTAMP', `LOCALTIMESTAMP()'

     `LOCALTIMESTAMP' and `LOCALTIMESTAMP()' are synonyms for `NOW()'.

   *  `MAKEDATE(YEAR,DAYOFYEAR)'

     Returns a date, given year and day-of-year values.  DAYOFYEAR must
     be greater than 0 or the result is `NULL'.

          mysql> SELECT MAKEDATE(2011,31), MAKEDATE(2011,32);
                  -> '2011-01-31', '2011-02-01'
          mysql> SELECT MAKEDATE(2011,365), MAKEDATE(2014,365);
                  -> '2011-12-31', '2014-12-31'
          mysql> SELECT MAKEDATE(2011,0);
                  -> NULL

   *  `MAKETIME(HOUR,MINUTE,SECOND)'

     Returns a time value calculated from the HOUR, MINUTE, and SECOND
     arguments.

          mysql> SELECT MAKETIME(12,15,30);
                  -> '12:15:30'

   *  `MICROSECOND(EXPR)'

     Returns the microseconds from the time or datetime expression EXPR
     as a number in the range from `0' to `999999'.

          mysql> SELECT MICROSECOND('12:00:00.123456');
                  -> 123456
          mysql> SELECT MICROSECOND('2009-12-31 23:59:59.000010');
                  -> 10

   *  `MINUTE(TIME)'

     Returns the minute for TIME, in the range `0' to `59'.

          mysql> SELECT MINUTE('2008-02-03 10:05:03');
                  -> 5

   *  `MONTH(DATE)'

     Returns the month for DATE, in the range `1' to `12' for January
     to December, or `0' for dates such as `'0000-00-00'' or
     `'2008-00-00'' that have a zero month part.

          mysql> SELECT MONTH('2008-02-03');
                  -> 2

   *  `MONTHNAME(DATE)'

     Returns the full name of the month for DATE. As of MySQL 5.0.25,
     the language used for the name is controlled by the value of the
     `lc_time_names' system variable (*Note locale-support::).

          mysql> SELECT MONTHNAME('2008-02-03');
                  -> 'February'

   *  `NOW()'

     Returns the current date and time as a value in `'YYYY-MM-DD
     HH:MM:SS'' or `YYYYMMDDHHMMSS.uuuuuu' format, depending on whether
     the function is used in a string or numeric context.  The value is
     expressed in the current time zone.

          mysql> SELECT NOW();
                  -> '2007-12-15 23:50:26'
          mysql> SELECT NOW() + 0;
                  -> 20071215235026.000000

     `NOW()' returns a constant time that indicates the time at which
     the statement began to execute. (Within a stored function or
     trigger, `NOW()' returns the time at which the function or
     triggering statement began to execute.) This differs from the
     behavior for `SYSDATE()', which returns the exact time at which it
     executes as of MySQL 5.0.12.

          mysql> SELECT NOW(), SLEEP(2), NOW();
          +---------------------+----------+---------------------+
          | NOW()               | SLEEP(2) | NOW()               |
          +---------------------+----------+---------------------+
          | 2006-04-12 13:47:36 |        0 | 2006-04-12 13:47:36 |
          +---------------------+----------+---------------------+

          mysql> SELECT SYSDATE(), SLEEP(2), SYSDATE();
          +---------------------+----------+---------------------+
          | SYSDATE()           | SLEEP(2) | SYSDATE()           |
          +---------------------+----------+---------------------+
          | 2006-04-12 13:47:44 |        0 | 2006-04-12 13:47:46 |
          +---------------------+----------+---------------------+

     In addition, the `SET TIMESTAMP' statement affects the value
     returned by `NOW()' but not by `SYSDATE()'. This means that
     timestamp settings in the binary log have no effect on invocations
     of `SYSDATE()'.  Setting the timestamp to a nonzero value causes
     each subsequent invocation of `NOW()' to return that value.
     Setting the timestamp to zero cancels this effect so that `NOW()'
     once again returns the current date and time.

     See the description for `SYSDATE()' for additional information
     about the differences between the two functions.

   *  `PERIOD_ADD(P,N)'

     Adds N months to period P (in the format `YYMM' or `YYYYMM').
     Returns a value in the format `YYYYMM'. Note that the period
     argument P is _not_ a date value.

          mysql> SELECT PERIOD_ADD(200801,2);
                  -> 200803

   *  `PERIOD_DIFF(P1,P2)'

     Returns the number of months between periods P1 and P2. P1 and P2
     should be in the format `YYMM' or `YYYYMM'. Note that the period
     arguments P1 and P2 are _not_ date values.

          mysql> SELECT PERIOD_DIFF(200802,200703);
                  -> 11

   *  `QUARTER(DATE)'

     Returns the quarter of the year for DATE, in the range `1' to `4'.

          mysql> SELECT QUARTER('2008-04-01');
                  -> 2

   *  `SECOND(TIME)'

     Returns the second for TIME, in the range `0' to `59'.

          mysql> SELECT SECOND('10:05:03');
                  -> 3

   *  `SEC_TO_TIME(SECONDS)'

     Returns the SECONDS argument, converted to hours, minutes, and
     seconds, as a *Note `TIME': time. value. The range of the result
     is constrained to that of the *Note `TIME': time. data type. A
     warning occurs if the argument corresponds to a value outside that
     range.

          mysql> SELECT SEC_TO_TIME(2378);
                  -> '00:39:38'
          mysql> SELECT SEC_TO_TIME(2378) + 0;
                  -> 3938

   *  `STR_TO_DATE(STR,FORMAT)'

     This is the inverse of the `DATE_FORMAT()' function. It takes a
     string STR and a format string FORMAT.  `STR_TO_DATE()' returns a
     *Note `DATETIME': datetime. value if the format string contains
     both date and time parts, or a *Note `DATE': datetime. or *Note
     `TIME': time. value if the string contains only date or time
     parts. If the date, time, or datetime value extracted from STR is
     illegal, `STR_TO_DATE()' returns `NULL' and, as of MySQL 5.0.3,
     produces a warning.

     The server scans STR attempting to match FORMAT to it. The format
     string can contain literal characters and format specifiers
     beginning with `%'. Literal characters in FORMAT must match
     literally in STR. Format specifiers in FORMAT must match a date or
     time part in STR. For the specifiers that can be used in FORMAT,
     see the `DATE_FORMAT()' function description.

          mysql> SELECT STR_TO_DATE('01,5,2013','%d,%m,%Y');
                  -> '2013-05-01'
          mysql> SELECT STR_TO_DATE('May 1, 2013','%M %d,%Y');
                  -> '2013-05-01'

     Scanning starts at the beginning of STR and fails if FORMAT is
     found not to match. Extra characters at the end of STR are ignored.

          mysql> SELECT STR_TO_DATE('a09:30:17','a%h:%i:%s');
                  -> '09:30:17'
          mysql> SELECT STR_TO_DATE('a09:30:17','%h:%i:%s');
                  -> NULL
          mysql> SELECT STR_TO_DATE('09:30:17a','%h:%i:%s');
                  -> '09:30:17'

     Unspecified date or time parts have a value of 0, so incompletely
     specified values in STR produce a result with some or all parts
     set to 0:

          mysql> SELECT STR_TO_DATE('abc','abc');
                  -> '0000-00-00'
          mysql> SELECT STR_TO_DATE('9','%m');
                  -> '0000-09-00'
          mysql> SELECT STR_TO_DATE('9','%s');
                  -> '00:00:09'

     Range checking on the parts of date values is as described in
     *Note datetime::. This means, for example, that `zero' dates or
     dates with part values of 0 are permitted unless the SQL mode is
     set to disallow such values.

          mysql> SELECT STR_TO_DATE('00/00/0000', '%m/%d/%Y');
                  -> '0000-00-00'
          mysql> SELECT STR_TO_DATE('04/31/2004', '%m/%d/%Y');
                  -> '2004-04-31'

     *Note*:

     You cannot use format `"%X%V"' to convert a year-week string to a
     date because the combination of a year and week does not uniquely
     identify a year and month if the week crosses a month boundary. To
     convert a year-week to a date, you should also specify the weekday:

          mysql> SELECT STR_TO_DATE('200442 Monday', '%X%V %W');
                  -> '2004-10-18'

   *  `SUBDATE(DATE,INTERVAL EXPR UNIT)', `SUBDATE(EXPR,DAYS)'

     When invoked with the `INTERVAL' form of the second argument,
     `SUBDATE()' is a synonym for `DATE_SUB()'. For information on the
     `INTERVAL' UNIT argument, see the discussion for `DATE_ADD()'.

          mysql> SELECT DATE_SUB('2008-01-02', INTERVAL 31 DAY);
                  -> '2007-12-02'
          mysql> SELECT SUBDATE('2008-01-02', INTERVAL 31 DAY);
                  -> '2007-12-02'

     The second form enables the use of an integer value for DAYS. In
     such cases, it is interpreted as the number of days to be
     subtracted from the date or datetime expression EXPR.

          mysql> SELECT SUBDATE('2008-01-02 12:00:00', 31);
                  -> '2007-12-02 12:00:00'

   *  `SUBTIME(EXPR1,EXPR2)'

     `SUBTIME()' returns EXPR1 - EXPR2 expressed as a value in the same
     format as EXPR1.  EXPR1 is a time or datetime expression, and
     EXPR2 is a time expression.

          mysql> SELECT SUBTIME('2007-12-31 23:59:59.999999','1 1:1:1.000002');
                  -> '2007-12-30 22:58:58.999997'
          mysql> SELECT SUBTIME('01:00:00.999999', '02:00:00.999998');
                  -> '-00:59:59.999999'

   *  `SYSDATE()'

     Returns the current date and time as a value in `'YYYY-MM-DD
     HH:MM:SS'' or `YYYYMMDDHHMMSS.uuuuuu' format, depending on whether
     the function is used in a string or numeric context.

     As of MySQL 5.0.12, `SYSDATE()' returns the time at which it
     executes. This differs from the behavior for `NOW()', which
     returns a constant time that indicates the time at which the
     statement began to execute. (Within a stored function or trigger,
     `NOW()' returns the time at which the function or triggering
     statement began to execute.)

          mysql> SELECT NOW(), SLEEP(2), NOW();
          +---------------------+----------+---------------------+
          | NOW()               | SLEEP(2) | NOW()               |
          +---------------------+----------+---------------------+
          | 2006-04-12 13:47:36 |        0 | 2006-04-12 13:47:36 |
          +---------------------+----------+---------------------+

          mysql> SELECT SYSDATE(), SLEEP(2), SYSDATE();
          +---------------------+----------+---------------------+
          | SYSDATE()           | SLEEP(2) | SYSDATE()           |
          +---------------------+----------+---------------------+
          | 2006-04-12 13:47:44 |        0 | 2006-04-12 13:47:46 |
          +---------------------+----------+---------------------+

     In addition, the `SET TIMESTAMP' statement affects the value
     returned by `NOW()' but not by `SYSDATE()'. This means that
     timestamp settings in the binary log have no effect on invocations
     of `SYSDATE()'.

     Because `SYSDATE()' can return different values even within the
     same statement, and is not affected by `SET TIMESTAMP', it is
     nondeterministic and therefore unsafe for replication. If that is
     a problem, you can start the server with the `--sysdate-is-now'
     option to cause `SYSDATE()' to be an alias for `NOW()'. The
     nondeterministic nature of `SYSDATE()' also means that indexes
     cannot be used for evaluating expressions that refer to it.

   *  `TIME(EXPR)'

     Extracts the time part of the time or datetime expression EXPR and
     returns it as a string.

          mysql> SELECT TIME('2003-12-31 01:02:03');
                  -> '01:02:03'
          mysql> SELECT TIME('2003-12-31 01:02:03.000123');
                  -> '01:02:03.000123'

   *  `TIMEDIFF(EXPR1,EXPR2)'

     `TIMEDIFF()' returns EXPR1 - EXPR2 expressed as a time value.
     EXPR1 and EXPR2 are time or date-and-time expressions, but both
     must be of the same type.

          mysql> SELECT TIMEDIFF('2000:01:01 00:00:00',
              ->                 '2000:01:01 00:00:00.000001');
                  -> '-00:00:00.000001'
          mysql> SELECT TIMEDIFF('2008-12-31 23:59:59.000001',
              ->                 '2008-12-30 01:01:01.000002');
                  -> '46:58:57.999999'

   *  `TIMESTAMP(EXPR)', `TIMESTAMP(EXPR1,EXPR2)'

     With a single argument, this function returns the date or datetime
     expression EXPR as a datetime value. With two arguments, it adds
     the time expression EXPR2 to the date or datetime expression EXPR1
     and returns the result as a datetime value.

          mysql> SELECT TIMESTAMP('2003-12-31');
                  -> '2003-12-31 00:00:00'
          mysql> SELECT TIMESTAMP('2003-12-31 12:00:00','12:00:00');
                  -> '2004-01-01 00:00:00'

   *  `TIMESTAMPADD(UNIT,INTERVAL,DATETIME_EXPR)'

     Adds the integer expression INTERVAL to the date or datetime
     expression DATETIME_EXPR. The unit for INTERVAL is given by the
     UNIT argument, which should be one of the following values:
     `FRAC_SECOND' (microseconds), `SECOND', `MINUTE', `HOUR', `DAY',
     `WEEK', `MONTH', `QUARTER', or `YEAR'.

     Beginning with MySQL 5.0.60, it is possible to use `MICROSECOND'
     in place of `FRAC_SECOND' with this function, and `FRAC_SECOND' is
     deprecated.  `FRAC_SECOND' is removed in MySQL 5.5.

     The UNIT value may be specified using one of keywords as shown, or
     with a prefix of `SQL_TSI_'. For example, `DAY' and `SQL_TSI_DAY'
     both are legal.

          mysql> SELECT TIMESTAMPADD(MINUTE,1,'2003-01-02');
                  -> '2003-01-02 00:01:00'
          mysql> SELECT TIMESTAMPADD(WEEK,1,'2003-01-02');
                  -> '2003-01-09'

     `TIMESTAMPADD()' is available as of MySQL 5.0.0.

   *  `TIMESTAMPDIFF(UNIT,DATETIME_EXPR1,DATETIME_EXPR2)'

     Returns DATETIME_EXPR2 - DATETIME_EXPR1, where DATETIME_EXPR1 and
     DATETIME_EXPR2 are date or datetime expressions. One expression
     may be a date and the other a datetime; a date value is treated as
     a datetime having the time part `'00:00:00'' where necessary. The
     unit for the result (an integer) is given by the UNIT argument.
     The legal values for UNIT are the same as those listed in the
     description of the `TIMESTAMPADD()' function.

          mysql> SELECT TIMESTAMPDIFF(MONTH,'2003-02-01','2003-05-01');
                  -> 3
          mysql> SELECT TIMESTAMPDIFF(YEAR,'2002-05-01','2001-01-01');
                  -> -1
          mysql> SELECT TIMESTAMPDIFF(MINUTE,'2003-02-01','2003-05-01 12:05:55');
                  -> 128885

     `TIMESTAMPDIFF()' is available as of MySQL 5.0.0.

     *Note*:

     The order of the date or datetime arguments for this function is
     the opposite of that used with the `TIMESTAMP()' function when
     invoked with 2 arguments.

   *  `TIME_FORMAT(TIME,FORMAT)'

     This is used like the `DATE_FORMAT()' function, but the FORMAT
     string may contain format specifiers only for hours, minutes,
     seconds, and microseconds.  Other specifiers produce a `NULL'
     value or `0'.

     If the TIME value contains an hour part that is greater than `23',
     the `%H' and `%k' hour format specifiers produce a value larger
     than the usual range of `0..23'. The other hour format specifiers
     produce the hour value modulo 12.

          mysql> SELECT TIME_FORMAT('100:00:00', '%H %k %h %I %l');
                  -> '100 100 04 04 4'

   *  `TIME_TO_SEC(TIME)'

     Returns the TIME argument, converted to seconds.

          mysql> SELECT TIME_TO_SEC('22:23:00');
                  -> 80580
          mysql> SELECT TIME_TO_SEC('00:39:38');
                  -> 2378

   *  `TO_DAYS(DATE)'

     Given a date DATE, returns a day number (the number of days since
     year 0).

          mysql> SELECT TO_DAYS(950501);
                  -> 728779
          mysql> SELECT TO_DAYS('2007-10-07');
                  -> 733321

     `TO_DAYS()' is not intended for use with values that precede the
     advent of the Gregorian calendar (1582), because it does not take
     into account the days that were lost when the calendar was
     changed. For dates before 1582 (and possibly a later year in other
     locales), results from this function are not reliable. See *Note
     mysql-calendar::, for details.

     Remember that MySQL converts two-digit year values in dates to
     four-digit form using the rules in *Note date-and-time-types::.
     For example, `'2008-10-07'' and `'08-10-07'' are seen as identical
     dates:

          mysql> SELECT TO_DAYS('2008-10-07'), TO_DAYS('08-10-07');
                  -> 733687, 733687

     In MySQL, the zero date is defined as `'0000-00-00'', even though
     this date is itself considered invalid. This means that, for
     `'0000-00-00'' and `'0000-01-01'', `TO_DAYS()' returns the values
     shown here:

          mysql> SELECT TO_DAYS('0000-00-00');
          +-----------------------+
          | to_days('0000-00-00') |
          +-----------------------+
          |                  NULL |
          +-----------------------+
          1 row in set, 1 warning (0.00 sec)

          mysql> SHOW WARNINGS;
          +---------+------+----------------------------------------+
          | Level   | Code | Message                                |
          +---------+------+----------------------------------------+
          | Warning | 1292 | Incorrect datetime value: '0000-00-00' |
          +---------+------+----------------------------------------+
          1 row in set (0.00 sec)

          mysql> SELECT TO_DAYS('0000-01-01');
          +-----------------------+
          | to_days('0000-01-01') |
          +-----------------------+
          |                     1 |
          +-----------------------+
          1 row in set (0.00 sec)

     This is true whether or not the `ALLOW_INVALID_DATES' SQL server
     mode (available in MySQL 5.0.2 and later) is enabled.

   *  `UNIX_TIMESTAMP()', `UNIX_TIMESTAMP(DATE)'

     If called with no argument, returns a Unix timestamp (seconds
     since `'1970-01-01 00:00:00'' UTC) as an unsigned integer. If
     `UNIX_TIMESTAMP()' is called with a DATE argument, it returns the
     value of the argument as seconds since `'1970-01-01 00:00:00''
     UTC. DATE may be a *Note `DATE': datetime. string, a *Note
     `DATETIME': datetime. string, a *Note `TIMESTAMP': datetime, or a
     number in the format `YYMMDD' or `YYYYMMDD'. The server interprets
     DATE as a value in the current time zone and converts it to an
     internal value in UTC. Clients can set their time zone as
     described in *Note time-zone-support::.

          mysql> SELECT UNIX_TIMESTAMP();
                  -> 1196440210
          mysql> SELECT UNIX_TIMESTAMP('2007-11-30 10:30:19');
                  -> 1196440219

     When `UNIX_TIMESTAMP()' is used on a *Note `TIMESTAMP': datetime.
     column, the function returns the internal timestamp value
     directly, with no implicit `string-to-Unix-timestamp' conversion.
     If you pass an out-of-range date to `UNIX_TIMESTAMP()', it returns
     `0'.

     Note: If you use `UNIX_TIMESTAMP()' and `FROM_UNIXTIME()' to
     convert between *Note `TIMESTAMP': datetime. values and Unix
     timestamp values, the conversion is lossy because the mapping is
     not one-to-one in both directions. For example, due to conventions
     for local time zone changes, it is possible for two
     `UNIX_TIMESTAMP()' to map two *Note `TIMESTAMP': datetime. values
     to the same Unix timestamp value.  `FROM_UNIXTIME()' will map that
     value back to only one of the original *Note `TIMESTAMP':
     datetime. values. Here is an example, using *Note `TIMESTAMP':
     datetime. values in the `CET' time zone:


          mysql> SELECT UNIX_TIMESTAMP('2005-03-27 03:00:00');
          +---------------------------------------+
          | UNIX_TIMESTAMP('2005-03-27 03:00:00') |
          +---------------------------------------+
          |                            1111885200 |
          +---------------------------------------+
          mysql> SELECT UNIX_TIMESTAMP('2005-03-27 02:00:00');
          +---------------------------------------+
          | UNIX_TIMESTAMP('2005-03-27 02:00:00') |
          +---------------------------------------+
          |                            1111885200 |
          +---------------------------------------+
          mysql> SELECT FROM_UNIXTIME(1111885200);
          +---------------------------+
          | FROM_UNIXTIME(1111885200) |
          +---------------------------+
          | 2005-03-27 03:00:00       |
          +---------------------------+

     If you want to subtract `UNIX_TIMESTAMP()' columns, you might want
     to cast the result to signed integers. See *Note cast-functions::.

   *  `UTC_DATE', `UTC_DATE()'

     Returns the current UTC date as a value in `'YYYY-MM-DD'' or
     `YYYYMMDD' format, depending on whether the function is used in a
     string or numeric context.

          mysql> SELECT UTC_DATE(), UTC_DATE() + 0;
                  -> '2003-08-14', 20030814

   *  `UTC_TIME', `UTC_TIME()'

     Returns the current UTC time as a value in `'HH:MM:SS'' or
     `HHMMSS.uuuuuu' format, depending on whether the function is used
     in a string or numeric context.

          mysql> SELECT UTC_TIME(), UTC_TIME() + 0;
                  -> '18:07:53', 180753.000000

   *  `UTC_TIMESTAMP', `UTC_TIMESTAMP()'

     Returns the current UTC date and time as a value in `'YYYY-MM-DD
     HH:MM:SS'' or `YYYYMMDDHHMMSS.uuuuuu' format, depending on whether
     the function is used in a string or numeric context.

          mysql> SELECT UTC_TIMESTAMP(), UTC_TIMESTAMP() + 0;
                  -> '2003-08-14 18:08:04', 20030814180804.000000

   *  `WEEK(DATE[,MODE])'

     This function returns the week number for DATE. The two-argument
     form of `WEEK()' enables you to specify whether the week starts on
     Sunday or Monday and whether the return value should be in the
     range from `0' to `53' or from `1' to `53'. If the MODE argument
     is omitted, the value of the `default_week_format' system variable
     is used. See *Note server-system-variables::.

     The following table describes how the MODE argument works.

     Mode    First day of  Range         Week 1 is the first week ...
             week                        
     0       Sunday        0-53          with a Sunday in this year
     1       Monday        0-53          with more than 3 days this year
     2       Sunday        1-53          with a Sunday in this year
     3       Monday        1-53          with more than 3 days this year
     4       Sunday        0-53          with more than 3 days this year
     5       Monday        0-53          with a Monday in this year
     6       Sunday        1-53          with more than 3 days this year
     7       Monday        1-53          with a Monday in this year

          mysql> SELECT WEEK('2008-02-20');
                  -> 7
          mysql> SELECT WEEK('2008-02-20',0);
                  -> 7
          mysql> SELECT WEEK('2008-02-20',1);
                  -> 8
          mysql> SELECT WEEK('2008-12-31',1);
                  -> 53

     Note that if a date falls in the last week of the previous year,
     MySQL returns `0' if you do not use `2', `3', `6', or `7' as the
     optional MODE argument:

          mysql> SELECT YEAR('2000-01-01'), WEEK('2000-01-01',0);
                  -> 2000, 0

     One might argue that MySQL should return `52' for the `WEEK()'
     function, because the given date actually occurs in the 52nd week
     of 1999. We decided to return `0' instead because we want the
     function to return `the week number in the given year.' This makes
     use of the `WEEK()' function reliable when combined with other
     functions that extract a date part from a date.

     If you would prefer the result to be evaluated with respect to the
     year that contains the first day of the week for the given date,
     use `0', `2', `5', or `7' as the optional MODE argument.

          mysql> SELECT WEEK('2000-01-01',2);
                  -> 52

     Alternatively, use the `YEARWEEK()' function:

          mysql> SELECT YEARWEEK('2000-01-01');
                  -> 199952
          mysql> SELECT MID(YEARWEEK('2000-01-01'),5,2);
                  -> '52'

   *  `WEEKDAY(DATE)'

     Returns the weekday index for DATE (`0' = Monday, `1' = Tuesday,
     ... `6' = Sunday).

          mysql> SELECT WEEKDAY('2008-02-03 22:23:00');
                  -> 6
          mysql> SELECT WEEKDAY('2007-11-06');
                  -> 1

   *  `WEEKOFYEAR(DATE)'

     Returns the calendar week of the date as a number in the range
     from `1' to `53'.  `WEEKOFYEAR()' is a compatibility function that
     is equivalent to `WEEK(DATE,3)'.

          mysql> SELECT WEEKOFYEAR('2008-02-20');
                  -> 8

   *  `YEAR(DATE)'

     Returns the year for DATE, in the range `1000' to `9999', or `0'
     for the `zero' date.

          mysql> SELECT YEAR('1987-01-01');
                  -> 1987

   *  `YEARWEEK(DATE)', `YEARWEEK(DATE,MODE)'

     Returns year and week for a date. The MODE argument works exactly
     like the MODE argument to `WEEK()'. The year in the result may be
     different from the year in the date argument for the first and the
     last week of the year.

          mysql> SELECT YEARWEEK('1987-01-01');
                  -> 198653

     Note that the week number is different from what the `WEEK()'
     function would return (`0') for optional arguments `0' or `1', as
     `WEEK()' then returns the week in the context of the given year.


File: manual.info,  Node: mysql-calendar,  Next: fulltext-search,  Prev: date-and-time-functions,  Up: functions

12.8 What Calendar Is Used By MySQL?
====================================

MySQL uses what is known as a _proleptic Gregorian calendar_.

Every country that has switched from the Julian to the Gregorian
calendar has had to discard at least ten days during the switch.  To
see how this works, consider the month of October 1582, when the first
Julian-to-Gregorian switch occurred.

Monday     Tuesday    Wednesday  Thursday   Friday     Saturday   Sunday
1          2          3          4          15         16         17
18         19         20         21         22         23         24
25         26         27         28         29         30         31

There are no dates between October 4 and October 15. This discontinuity
is called the _cutover_. Any dates before the cutover are Julian, and
any dates following the cutover are Gregorian. Dates during a cutover
are nonexistent.

A calendar applied to dates when it was not actually in use is called
_proleptic_. Thus, if we assume there was never a cutover and Gregorian
rules always rule, we have a proleptic Gregorian calendar. This is what
is used by MySQL, as is required by standard SQL. For this reason,
dates prior to the cutover stored as MySQL *Note `DATE': datetime. or
*Note `DATETIME': datetime. values must be adjusted to compensate for
the difference. It is important to realize that the cutover did not
occur at the same time in all countries, and that the later it
happened, the more days were lost. For example, in Great Britain, it
took place in 1752, when Wednesday September 2 was followed by Thursday
September 14. Russia remained on the Julian calendar until 1918, losing
13 days in the process, and what is popularly referred to as its
`October Revolution' occurred in November according to the Gregorian
calendar.


File: manual.info,  Node: fulltext-search,  Next: cast-functions,  Prev: mysql-calendar,  Up: functions

12.9 Full-Text Search Functions
===============================

* Menu:

* fulltext-natural-language::    Natural Language Full-Text Searches
* fulltext-boolean::             Boolean Full-Text Searches
* fulltext-query-expansion::     Full-Text Searches with Query Expansion
* fulltext-stopwords::           Full-Text Stopwords
* fulltext-restrictions::        Full-Text Restrictions
* fulltext-fine-tuning::         Fine-Tuning MySQL Full-Text Search
* full-text-adding-collation::   Adding a Collation for Full-Text Indexing

`MATCH (COL1,COL2,...)  AGAINST (EXPR [SEARCH_MODIFIER])'

     SEARCH_MODIFIER: { IN BOOLEAN MODE | WITH QUERY EXPANSION }

MySQL has support for full-text indexing and searching:

   * A full-text index in MySQL is an index of type `FULLTEXT'.

   * Full-text indexes can be used only with `MyISAM' tables, and can
     be created only for *Note `CHAR': char, *Note `VARCHAR': char, or
     *Note `TEXT': blob. columns.

   * A `FULLTEXT' index definition can be given in the *Note `CREATE
     TABLE': create-table. statement when a table is created, or added
     later using *Note `ALTER TABLE': alter-table. or *Note `CREATE
     INDEX': create-index.

   * For large data sets, it is much faster to load your data into a
     table that has no `FULLTEXT' index and then create the index after
     that, than to load data into a table that has an existing
     `FULLTEXT' index.

Full-text searching is performed using `MATCH() ... AGAINST' syntax.
`MATCH()' takes a comma-separated list that names the columns to be
searched.  `AGAINST' takes a string to search for, and an optional
modifier that indicates what type of search to perform.  The search
string must be a literal string, not a variable or a column name. There
are three types of full-text searches:

   * A boolean search interprets the search string using the rules of a
     special query language. The string contains the words to search
     for. It can also contain operators that specify requirements such
     that a word must be present or absent in matching rows, or that it
     should be weighted higher or lower than usual. Common words such
     as `some' or `then' are stopwords and do not match if present in
     the search string. The `IN BOOLEAN MODE' modifier specifies a
     boolean search. For more information, see *Note fulltext-boolean::.

   * A natural language search interprets the search string as a phrase
     in natural human language (a phrase in free text).  There are no
     special operators. The stopword list applies. In addition, words
     that are present in 50% or more of the rows are considered common
     and do not match. Full-text searches are natural language searches
     if no modifier is given.

   * A query expansion search is a modification of a natural language
     search. The search string is used to perform a natural language
     search. Then words from the most relevant rows returned by the
     search are added to the search string and the search is done
     again. The query returns the rows from the second search. The
     `WITH QUERY EXPANSION' modifier specifies a query expansion
     search. For more information, see *Note fulltext-query-expansion::.

Constraints on full-text searching are listed in *Note
fulltext-restrictions::.

The *Note `myisam_ftdump': myisam-ftdump. utility can be used to dump
the contents of a full-text index. This may be helpful for debugging
full-text queries. See *Note myisam-ftdump::.


File: manual.info,  Node: fulltext-natural-language,  Next: fulltext-boolean,  Prev: fulltext-search,  Up: fulltext-search

12.9.1 Natural Language Full-Text Searches
------------------------------------------

By default, the `MATCH()' function performs a natural language search
for a string against a _text collection_. A collection is a set of one
or more columns included in a `FULLTEXT' index. The search string is
given as the argument to `AGAINST()'. For each row in the table,
`MATCH()' returns a relevance value; that is, a similarity measure
between the search string and the text in that row in the columns named
in the `MATCH()' list.

     mysql> CREATE TABLE articles (
         ->   id INT UNSIGNED AUTO_INCREMENT NOT NULL PRIMARY KEY,
         ->   title VARCHAR(200),
         ->   body TEXT,
         ->   FULLTEXT (title,body)
         -> ) ENGINE=MyISAM;
     Query OK, 0 rows affected (0.00 sec)

     mysql> INSERT INTO articles (title,body) VALUES
         -> ('MySQL Tutorial','DBMS stands for DataBase ...'),
         -> ('How To Use MySQL Well','After you went through a ...'),
         -> ('Optimizing MySQL','In this tutorial we will show ...'),
         -> ('1001 MySQL Tricks','1. Never run mysqld as root. 2. ...'),
         -> ('MySQL vs. YourSQL','In the following database comparison ...'),
         -> ('MySQL Security','When configured properly, MySQL ...');
     Query OK, 6 rows affected (0.00 sec)
     Records: 6  Duplicates: 0  Warnings: 0

     mysql> SELECT * FROM articles
         -> WHERE MATCH (title,body) AGAINST ('database');
     +----+-------------------+------------------------------------------+
     | id | title             | body                                     |
     +----+-------------------+------------------------------------------+
     |  5 | MySQL vs. YourSQL | In the following database comparison ... |
     |  1 | MySQL Tutorial    | DBMS stands for DataBase ...             |
     +----+-------------------+------------------------------------------+
     2 rows in set (0.00 sec)

By default, the search is performed in case-insensitive fashion.
However, you can perform a case-sensitive full-text search by using a
binary collation for the indexed columns. For example, a column that
uses the `latin1' character set of can be assigned a collation of
`latin1_bin' to make it case sensitive for full-text searches.

When `MATCH()' is used in a `WHERE' clause, as in the example shown
earlier, the rows returned are automatically sorted with the highest
relevance first. Relevance values are nonnegative floating-point
numbers. Zero relevance means no similarity.  Relevance is computed
based on the number of words in the row, the number of unique words in
that row, the total number of words in the collection, and the number
of documents (rows) that contain a particular word.

To simply count matches, you could use a query like this:

     mysql> SELECT COUNT(*) FROM articles
         -> WHERE MATCH (title,body)
         -> AGAINST ('database');
     +----------+
     | COUNT(*) |
     +----------+
     |        2 |
     +----------+
     1 row in set (0.00 sec)

However, you might find it quicker to rewrite the query as follows:

     mysql> SELECT
         -> COUNT(IF(MATCH (title,body) AGAINST ('database'), 1, NULL))
         -> AS count
         -> FROM articles;
     +-------+
     | count |
     +-------+
     |     2 |
     +-------+
     1 row in set (0.00 sec)

The first query sorts the results by relevance whereas the second does
not. However, the second query performs a full table scan and the first
does not. The first may be faster if the search matches few rows;
otherwise, the second may be faster because it would read many rows
anyway.

For natural-language full-text searches, it is a requirement that the
columns named in the `MATCH()' function be the same columns included in
some `FULLTEXT' index in your table. For the preceding query, note that
the columns named in the `MATCH()' function (`title' and `body') are the
same as those named in the definition of the `article' table's
`FULLTEXT' index. If you wanted to search the `title' or `body'
separately, you would need to create separate `FULLTEXT' indexes for
each column.

It is also possible to perform a boolean search or a search with query
expansion. These search types are described in *Note
fulltext-boolean::, and *Note fulltext-query-expansion::.

A full-text search that uses an index can name columns only from a
single table in the `MATCH()' clause because an index cannot span
multiple tables. A boolean search can be done in the absence of an
index (albeit more slowly), in which case it is possible to name
columns from multiple tables.

The preceding example is a basic illustration that shows how to use the
`MATCH()' function where rows are returned in order of decreasing
relevance. The next example shows how to retrieve the relevance values
explicitly.  Returned rows are not ordered because the *Note `SELECT':
select. statement includes neither `WHERE' nor `ORDER BY' clauses:

     mysql> SELECT id, MATCH (title,body) AGAINST ('Tutorial')
         -> FROM articles;
     +----+-----------------------------------------+
     | id | MATCH (title,body) AGAINST ('Tutorial') |
     +----+-----------------------------------------+
     |  1 |                        0.65545833110809 |
     |  2 |                                       0 |
     |  3 |                        0.66266459226608 |
     |  4 |                                       0 |
     |  5 |                                       0 |
     |  6 |                                       0 |
     +----+-----------------------------------------+
     6 rows in set (0.00 sec)

The following example is more complex. The query returns the relevance
values and it also sorts the rows in order of decreasing relevance. To
achieve this result, you should specify `MATCH()' twice: once in the
*Note `SELECT': select. list and once in the `WHERE' clause. This
causes no additional overhead, because the MySQL optimizer notices that
the two `MATCH()' calls are identical and invokes the full-text search
code only once.

     mysql> SELECT id, body, MATCH (title,body) AGAINST
         -> ('Security implications of running MySQL as root') AS score
         -> FROM articles WHERE MATCH (title,body) AGAINST
         -> ('Security implications of running MySQL as root');
     +----+-------------------------------------+-----------------+
     | id | body                                | score           |
     +----+-------------------------------------+-----------------+
     |  4 | 1. Never run mysqld as root. 2. ... | 1.5219271183014 |
     |  6 | When configured properly, MySQL ... | 1.3114095926285 |
     +----+-------------------------------------+-----------------+
     2 rows in set (0.00 sec)

The MySQL `FULLTEXT' implementation regards any sequence of true word
characters (letters, digits, and underscores) as a word. That sequence
may also contain apostrophes (``'''), but not more than one in a row.
This means that `aaa'bbb' is regarded as one word, but `aaa''bbb' is
regarded as two words. Apostrophes at the beginning or the end of a
word are stripped by the `FULLTEXT' parser; `'aaa'bbb'' would be parsed
as `aaa'bbb'.

The `FULLTEXT' parser determines where words start and end by looking
for certain delimiter characters; for example, `` '' (space), ``,''
(comma), and ``.'' (period). If words are not separated by delimiters
(as in, for example, Chinese), the `FULLTEXT' parser cannot determine
where a word begins or ends. To be able to add words or other indexed
terms in such languages to a `FULLTEXT' index, you must preprocess them
so that they are separated by some arbitrary delimiter such as ``"''.

Some words are ignored in full-text searches:

   * Any word that is too short is ignored. The default minimum length
     of words that are found by full-text searches is four characters.

   * Words in the stopword list are ignored. A stopword is a word such
     as `the' or `some' that is so common that it is considered to have
     zero semantic value.  There is a built-in stopword list, but it
     can be overwritten by a user-defined list.

The default stopword list is given in *Note fulltext-stopwords::. The
default minimum word length and stopword list can be changed as
described in *Note fulltext-fine-tuning::.

Every correct word in the collection and in the query is weighted
according to its significance in the collection or query. Consequently,
a word that is present in many documents has a lower weight (and may
even have a zero weight), because it has lower semantic value in this
particular collection.  Conversely, if the word is rare, it receives a
higher weight.  The weights of the words are combined to compute the
relevance of the row.

Such a technique works best with large collections (in fact, it was
carefully tuned this way). For very small tables, word distribution
does not adequately reflect their semantic value, and this model may
sometimes produce bizarre results. For example, although the word
`MySQL' is present in every row of the `articles' table shown earlier,
a search for the word produces no results:

     mysql> SELECT * FROM articles
         -> WHERE MATCH (title,body) AGAINST ('MySQL');
     Empty set (0.00 sec)

The search result is empty because the word `MySQL' is present in at
least 50% of the rows. As such, it is effectively treated as a
stopword. For large data sets, this is the most desirable behavior: A
natural language query should not return every second row from a 1GB
table. For small data sets, it may be less desirable.

A word that matches half of the rows in a table is less likely to
locate relevant documents. In fact, it most likely finds plenty of
irrelevant documents. We all know this happens far too often when we
are trying to find something on the Internet with a search engine. It
is with this reasoning that rows containing the word are assigned a low
semantic value for _the particular data set in which they occur_. A
given word may reach the 50% threshold in one data set but not another.

The 50% threshold has a significant implication when you first try
full-text searching to see how it works: If you create a table and
insert only one or two rows of text into it, every word in the text
occurs in at least 50% of the rows. As a result, no search returns any
results. Be sure to insert at least three rows, and preferably many
more. Users who need to bypass the 50% limitation can use the boolean
search mode; see *Note fulltext-boolean::.


File: manual.info,  Node: fulltext-boolean,  Next: fulltext-query-expansion,  Prev: fulltext-natural-language,  Up: fulltext-search

12.9.2 Boolean Full-Text Searches
---------------------------------

MySQL can perform boolean full-text searches using the `IN BOOLEAN
MODE' modifier. With this modifier, certain characters have special
meaning at the beginning or end of words in the search string. In the
following query, the `+' and `-' operators indicate that a word is
required to be present or absent, respectively, for a match to occur.
Thus, the query retrieves all the rows that contain the word `MySQL'
but that do _not_ contain the word `YourSQL':

     mysql> SELECT * FROM articles WHERE MATCH (title,body)
         -> AGAINST ('+MySQL -YourSQL' IN BOOLEAN MODE);
     +----+-----------------------+-------------------------------------+
     | id | title                 | body                                |
     +----+-----------------------+-------------------------------------+
     |  1 | MySQL Tutorial        | DBMS stands for DataBase ...        |
     |  2 | How To Use MySQL Well | After you went through a ...        |
     |  3 | Optimizing MySQL      | In this tutorial we will show ...   |
     |  4 | 1001 MySQL Tricks     | 1. Never run mysqld as root. 2. ... |
     |  6 | MySQL Security        | When configured properly, MySQL ... |
     +----+-----------------------+-------------------------------------+

*Note*:

In implementing this feature, MySQL uses what is sometimes referred to
as _implied Boolean logic_, in which

   * `+' stands for `AND'

   * `-' stands for `NOT'

   * [_no operator_] implies `OR'

Boolean full-text searches have these characteristics:

   * They do not use the 50% threshold.

   * They do not automatically sort rows in order of decreasing
     relevance. You can see this from the preceding query result: The
     row with the highest relevance is the one that contains `MySQL'
     twice, but it is listed last, not first.

   * They can work even without a `FULLTEXT' index, although a search
     executed in this fashion would be quite slow.

   * The minimum and maximum word length full-text parameters apply.

   * The stopword list applies.

The boolean full-text search capability supports the following
operators:

   * `+'

     A leading plus sign indicates that this word _must_ be present in
     each row that is returned.

   * `-'

     A leading minus sign indicates that this word must _not_ be
     present in any of the rows that are returned.

     Note: The `-' operator acts only to exclude rows that are
     otherwise matched by other search terms. Thus, a boolean-mode
     search that contains only terms preceded by `-' returns an empty
     result. It does not return `all rows except those containing any
     of the excluded terms.'

   * (no operator)

     By default (when neither `+' nor `-' is specified) the word is
     optional, but the rows that contain it are rated higher. This
     mimics the behavior of `MATCH() ...  AGAINST()' without the `IN
     BOOLEAN MODE' modifier.

   * `> <'

     These two operators are used to change a word's contribution to
     the relevance value that is assigned to a row. The `>' operator
     increases the contribution and the `<' operator decreases it. See
     the example following this list.

   * `( )'

     Parentheses group words into subexpressions. Parenthesized groups
     can be nested.

   * `~'

     A leading tilde acts as a negation operator, causing the word's
     contribution to the row's relevance to be negative.  This is
     useful for marking `noise' words. A row containing such a word is
     rated lower than others, but is not excluded altogether, as it
     would be with the `-' operator.

   * `*'

     The asterisk serves as the truncation (or wildcard) operator.
     Unlike the other operators, it should be _appended_ to the word to
     be affected.  Words match if they begin with the word preceding the
     `*' operator.

     If a word is specified with the truncation operator, it is not
     stripped from a boolean query, even if it is too short (as
     determined from the `ft_min_word_len' setting) or a stopword. This
     occurs because the word is not seen as too short or a stopword,
     but as a prefix that must be present in the document in the form
     of a word that begins with the prefix. Suppose that
     `ft_min_word_len=4'.  `ft_min_word_len=4'. Then a search for
     `'+WORD +the*'' will likely return fewer rows than a search for
     `'+WORD +the'':

        * The former query remains as is and requires both WORD and
          `the*' (a word starting with `the') to be present in the
          document.

        * The latter query is transformed to `+WORD' (requiring only
          WORD to be present). `the' is both too short and a stopword,
          and either condition is enough to cause it to be ignored.

   * `"'

     A phrase that is enclosed within double quote (``"'') characters
     matches only rows that contain the phrase _literally, as it was
     typed_. The full-text engine splits the phrase into words and
     performs a search in the `FULLTEXT' index for the words. Prior to
     MySQL 5.0.3, the engine then performed a substring search for the
     phrase in the records that were found, so the match must include
     nonword characters in the phrase. As of MySQL 5.0.3, nonword
     characters need not be matched exactly: Phrase searching requires
     only that matches contain exactly the same words as the phrase and
     in the same order. For example, `"test phrase"' matches `"test,
     phrase"' in MySQL 5.0.3, but not before.

     If the phrase contains no words that are in the index, the result
     is empty. For example, if all words are either stopwords or
     shorter than the minimum length of indexed words, the result is
     empty.

The following examples demonstrate some search strings that use boolean
full-text operators:

   * `'apple banana''

     Find rows that contain at least one of the two words.

   * `'+apple +juice''

     Find rows that contain both words.

   * `'+apple macintosh''

     Find rows that contain the word `apple', but rank rows higher if
     they also contain `macintosh'.

   * `'+apple -macintosh''

     Find rows that contain the word `apple' but not `macintosh'.

   * `'+apple ~macintosh''

     Find rows that contain the word `apple', but if the row also
     contains the word `macintosh', rate it lower than if row does not.
     This is `softer' than a search for `'+apple -macintosh'', for
     which the presence of `macintosh' causes the row not to be returned
     at all.

   * `'+apple +(>turnover <strudel)''

     Find rows that contain the words `apple' and `turnover', or
     `apple' and `strudel' (in any order), but rank `apple turnover'
     higher than `apple strudel'.

   * `'apple*''

     Find rows that contain words such as `apple', `apples',
     `applesauce', or `applet'.

   * `'"some words"''

     Find rows that contain the exact phrase `some words' (for example,
     rows that contain `some words of wisdom' but not `some noise
     words'). Note that the ``"'' characters that enclose the phrase
     are operator characters that delimit the phrase.  They are not the
     quotation marks that enclose the search string itself.


File: manual.info,  Node: fulltext-query-expansion,  Next: fulltext-stopwords,  Prev: fulltext-boolean,  Up: fulltext-search

12.9.3 Full-Text Searches with Query Expansion
----------------------------------------------

Full-text search supports query expansion (and in particular, its
variant `blind query expansion'). This is generally useful when a
search phrase is too short, which often means that the user is relying
on implied knowledge that the full-text search engine lacks. For
example, a user searching for `database' may really mean that `MySQL',
`Oracle', `DB2', and `RDBMS' all are phrases that should match
`databases' and should be returned, too. This is implied knowledge.

Blind query expansion (also known as automatic relevance feedback) is
enabled by adding `WITH QUERY EXPANSION' following the search phrase.
It works by performing the search twice, where the search phrase for the
second search is the original search phrase concatenated with the few
most highly relevant documents from the first search.  Thus, if one of
these documents contains the word `databases' and the word `MySQL', the
second search finds the documents that contain the word `MySQL' even if
they do not contain the word `database'. The following example shows
this difference:

     mysql> SELECT * FROM articles
         -> WHERE MATCH (title,body) AGAINST ('database');
     +----+-------------------+------------------------------------------+
     | id | title             | body                                     |
     +----+-------------------+------------------------------------------+
     |  5 | MySQL vs. YourSQL | In the following database comparison ... |
     |  1 | MySQL Tutorial    | DBMS stands for DataBase ...             |
     +----+-------------------+------------------------------------------+
     2 rows in set (0.00 sec)

     mysql> SELECT * FROM articles
         -> WHERE MATCH (title,body)
         -> AGAINST ('database' WITH QUERY EXPANSION);
     +----+-------------------+------------------------------------------+
     | id | title             | body                                     |
     +----+-------------------+------------------------------------------+
     |  1 | MySQL Tutorial    | DBMS stands for DataBase ...             |
     |  5 | MySQL vs. YourSQL | In the following database comparison ... |
     |  3 | Optimizing MySQL  | In this tutorial we will show ...        |
     +----+-------------------+------------------------------------------+
     3 rows in set (0.00 sec)

Another example could be searching for books by Georges Simenon about
Maigret, when a user is not sure how to spell `Maigret'. A search for
`Megre and the reluctant witnesses' finds only `Maigret and the
Reluctant Witnesses' without query expansion. A search with query
expansion finds all books with the word `Maigret' on the second pass.

*Note*:

Because blind query expansion tends to increase noise significantly by
returning nonrelevant documents, it is meaningful to use only when a
search phrase is rather short.


File: manual.info,  Node: fulltext-stopwords,  Next: fulltext-restrictions,  Prev: fulltext-query-expansion,  Up: fulltext-search

12.9.4 Full-Text Stopwords
--------------------------

The stopword list is loaded and searched for full-text queries using
the server character set and collation (the values of the
`character_set_server' and `collation_server' system variables). False
hits or misses may occur for stopword lookups if the stopword file or
columns used for full-text indexing or searches have a character set or
collation different from `character_set_server' or `collation_server'.

Case sensitivity of stopword lookups depends on the server collation.
For example, lookups are case insensitive if the collation is
`latin1_swedish_ci', whereas lookups are case sensitive if the
collation is `latin1_general_cs' or `latin1_bin'.

The following table shows the default list of full-text stopwords. In a
MySQL source distribution, you can find this list in the
`myisam/ft_static.c' file.

a's            able           about          above          according
accordingly    across         actually       after          afterwards
again          against        ain't          all            allow
allows         almost         alone          along          already
also           although       always         am             among
amongst        an             and            another        any
anybody        anyhow         anyone         anything       anyway
anyways        anywhere       apart          appear         appreciate
appropriate    are            aren't         around         as
aside          ask            asking         associated     at
available      away           awfully        be             became
because        become         becomes        becoming       been
before         beforehand     behind         being          believe
below          beside         besides        best           better
between        beyond         both           brief          but
by             c'mon          c's            came           can
can't          cannot         cant           cause          causes
certain        certainly      changes        clearly        co
com            come           comes          concerning     consequently
consider       considering    contain        containing     contains
corresponding  could          couldn't       course         currently
definitely     described      despite        did            didn't
different      do             does           doesn't        doing
don't          done           down           downwards      during
each           edu            eg             eight          either
else           elsewhere      enough         entirely       especially
et             etc            even           ever           every
everybody      everyone       everything     everywhere     ex
exactly        example        except         far            few
fifth          first          five           followed       following
follows        for            former         formerly       forth
four           from           further        furthermore    get
gets           getting        given          gives          go
goes           going          gone           got            gotten
greetings      had            hadn't         happens        hardly
has            hasn't         have           haven't        having
he             he's           hello          help           hence
her            here           here's         hereafter      hereby
herein         hereupon       hers           herself        hi
him            himself        his            hither         hopefully
how            howbeit        however        i'd            i'll
i'm            i've           ie             if             ignored
immediate      in             inasmuch       inc            indeed
indicate       indicated      indicates      inner          insofar
instead        into           inward         is             isn't
it             it'd           it'll          it's           its
itself         just           keep           keeps          kept
know           known          knows          last           lately
later          latter         latterly       least          less
lest           let            let's          like           liked
likely         little         look           looking        looks
ltd            mainly         many           may            maybe
me             mean           meanwhile      merely         might
more           moreover       most           mostly         much
must           my             myself         name           namely
nd             near           nearly         necessary      need
needs          neither        never          nevertheless   new
next           nine           no             nobody         non
none           noone          nor            normally       not
nothing        novel          now            nowhere        obviously
of             off            often          oh             ok
okay           old            on             once           one
ones           only           onto           or             other
others         otherwise      ought          our            ours
ourselves      out            outside        over           overall
own            particular     particularly   per            perhaps
placed         please         plus           possible       presumably
probably       provides       que            quite          qv
rather         rd             re             really         reasonably
regarding      regardless     regards        relatively     respectively
right          said           same           saw            say
saying         says           second         secondly       see
seeing         seem           seemed         seeming        seems
seen           self           selves         sensible       sent
serious        seriously      seven          several        shall
she            should         shouldn't      since          six
so             some           somebody       somehow        someone
something      sometime       sometimes      somewhat       somewhere
soon           sorry          specified      specify        specifying
still          sub            such           sup            sure
t's            take           taken          tell           tends
th             than           thank          thanks         thanx
that           that's         thats          the            their
theirs         them           themselves     then           thence
there          there's        thereafter     thereby        therefore
therein        theres         thereupon      these          they
they'd         they'll        they're        they've        think
third          this           thorough       thoroughly     those
though         three          through        throughout     thru
thus           to             together       too            took
toward         towards        tried          tries          truly
try            trying         twice          two            un
under          unfortunately  unless         unlikely       until
unto           up             upon           us             use
used           useful         uses           using          usually
value          various        very           via            viz
vs             want           wants          was            wasn't
way            we             we'd           we'll          we're
we've          welcome        well           went           were
weren't        what           what's         whatever       when
whence         whenever       where          where's        whereafter
whereas        whereby        wherein        whereupon      wherever
whether        which          while          whither        who
who's          whoever        whole          whom           whose
why            will           willing        wish           with
within         without        won't          wonder         would
wouldn't       yes            yet            you            you'd
you'll         you're         you've         your           yours
yourself       yourselves     zero                          


File: manual.info,  Node: fulltext-restrictions,  Next: fulltext-fine-tuning,  Prev: fulltext-stopwords,  Up: fulltext-search

12.9.5 Full-Text Restrictions
-----------------------------

   * Full-text searches are supported for `MyISAM' tables only.

   * Full-text searches can be used with most multi-byte character
     sets. The exception is that for Unicode, the `utf8' character set
     can be used, but not the `ucs2' character set. However, although
     `FULLTEXT' indexes on `ucs2' columns cannot be used, you can
     perform `IN BOOLEAN MODE' searches on a `ucs2' column that has no
     such index.

   * Ideographic languages such as Chinese and Japanese do not have
     word delimiters. Therefore, the `FULLTEXT' parser _cannot
     determine where words begin and end in these and other such
     languages_. The implications of this and some workarounds for the
     problem are described in *Note fulltext-search::.

   * Although the use of multiple character sets within a single table
     is supported, all columns in a `FULLTEXT' index must use the same
     character set and collation.

   * The `MATCH()' column list must match exactly the column list in
     some `FULLTEXT' index definition for the table, unless this
     `MATCH()' is `IN BOOLEAN MODE'. Boolean-mode searches can be done
     on nonindexed columns, although they are likely to be slow.

   * The argument to `AGAINST()' must be a constant string.

   * Index hints are more limited for `FULLTEXT' searches than for
     non-`FULLTEXT' searches.  See *Note index-hints::.


File: manual.info,  Node: fulltext-fine-tuning,  Next: full-text-adding-collation,  Prev: fulltext-restrictions,  Up: fulltext-search

12.9.6 Fine-Tuning MySQL Full-Text Search
-----------------------------------------

MySQL's full-text search capability has few user-tunable parameters.
You can exert more control over full-text searching behavior if you
have a MySQL source distribution because some changes require source
code modifications. See *Note source-installation::.

Note that full-text search is carefully tuned for the most
effectiveness. Modifying the default behavior in most cases can
actually decrease effectiveness. _Do not alter the MySQL sources unless
you know what you are doing_.

Most full-text variables described in this section must be set at
server startup time. A server restart is required to change them; they
cannot be modified while the server is running.

Some variable changes require that you rebuild the `FULLTEXT' indexes
in your tables. Instructions for doing so are given later in this
section.

   * The minimum and maximum lengths of words to be indexed are defined
     by the `ft_min_word_len' and `ft_max_word_len' system variables.
     (See *Note server-system-variables::.)  The default minimum value
     is four characters; the default maximum is version dependent. If
     you change either value, you must rebuild your `FULLTEXT' indexes.
     For example, if you want three-character words to be searchable,
     you can set the `ft_min_word_len' variable by putting the
     following lines in an option file:

          [mysqld]
          ft_min_word_len=3

     Then restart the server and rebuild your `FULLTEXT' indexes. Note
     particularly the remarks regarding *Note `myisamchk': myisamchk.
     in the instructions following this list.

   * To override the default stopword list, set the `ft_stopword_file'
     system variable. (See *Note server-system-variables::.)  The
     variable value should be the path name of the file containing the
     stopword list, or the empty string to disable stopword filtering.
     The server looks for the file in the data directory unless an
     absolute path name is given to specify a different directory.
     After changing the value of this variable or the contents of the
     stopword file, restart the server and rebuild your `FULLTEXT'
     indexes.

     The stopword list is free-form. That is, you may use any
     nonalphanumeric character such as newline, space, or comma to
     separate stopwords. Exceptions are the underscore character
     (``_'') and a single apostrophe (``''') which are treated as part
     of a word. The character set of the stopword list is the server's
     default character set; see *Note charset-server::.

   * The 50% threshold for natural language searches is determined by
     the particular weighting scheme chosen. To disable it, look for
     the following line in `myisam/ftdefs.h':

          #define GWS_IN_USE GWS_PROB

     Change that line to this:

          #define GWS_IN_USE GWS_FREQ

     Then recompile MySQL. There is no need to rebuild the indexes in
     this case.

     *Note*:

     By making this change, you _severely_ decrease MySQL's ability to
     provide adequate relevance values for the `MATCH()' function. If
     you really need to search for such common words, it would be
     better to search using `IN BOOLEAN MODE' instead, which does not
     observe the 50% threshold.

   * To change the operators used for boolean full-text searches, set
     the `ft_boolean_syntax' system variable. This variable can be
     changed while the server is running, but you must have the `SUPER'
     privilege to do so. No rebuilding of indexes is necessary in this
     case. See *Note server-system-variables::, which describes the
     rules governing how to set this variable.

   * If you want to change the set of characters that are considered
     word characters, you can do so in several ways, as described in
     the following list. After making the modification, you must
     rebuild the indexes for each table that contains any `FULLTEXT'
     indexes.  Suppose that you want to treat the hyphen character
     ('-') as a word character. Use one of these methods:

        * Modify the MySQL source: In `myisam/ftdefs.h', see the
          `true_word_char()' and `misc_word_char()' macros. Add `'-''
          to one of those macros and recompile MySQL.

        * Modify a character set file: This requires no recompilation.
          The `true_word_char()' macro uses a `character type' table to
          distinguish letters and numbers from other characters. .  You
          can edit the contents of the `<ctype><map>' array in one of
          the character set XML files to specify that `'-'' is a
          `letter.' Then use the given character set for your
          `FULLTEXT' indexes. For information about the `<ctype><map>'
          array format, see *Note character-arrays::.

        * Add a new collation for the character set used by the indexed
          columns, and alter the columns to use that collation. For
          general information about adding collations, see *Note
          adding-collation::. For an example specific to full-text
          indexing, see *Note full-text-adding-collation::.

If you modify full-text variables that affect indexing
(`ft_min_word_len', `ft_max_word_len', or `ft_stopword_file'), or if you
change the stopword file itself, you must rebuild your `FULLTEXT'
indexes after making the changes and restarting the server. To rebuild
the indexes in this case, it is sufficient to do a `QUICK' repair
operation:

     mysql> REPAIR TABLE TBL_NAME QUICK;

Alternatively, use *Note `ALTER TABLE': alter-table.  with the `DROP
INDEX' and `ADD INDEX' options to drop and re-create each `FULLTEXT'
index. In some cases, this may be faster than a repair operation.

Each table that contains any `FULLTEXT' index must be repaired as just
shown. Otherwise, queries for the table may yield incorrect results,
and modifications to the table will cause the server to see the table
as corrupt and in need of repair.

Note that if you use *Note `myisamchk': myisamchk. to perform an
operation that modifies table indexes (such as repair or analyze), the
`FULLTEXT' indexes are rebuilt using the _default_ full-text parameter
values for minimum word length, maximum word length, and stopword file
unless you specify otherwise. This can result in queries failing.

The problem occurs because these parameters are known only by the
server. They are not stored in `MyISAM' index files. To avoid the
problem if you have modified the minimum or maximum word length or
stopword file values used by the server, specify the same
`ft_min_word_len', `ft_max_word_len', and `ft_stopword_file' values for
*Note `myisamchk': myisamchk. that you use for *Note `mysqld': mysqld.
For example, if you have set the minimum word length to 3, you can
repair a table with *Note `myisamchk': myisamchk. like this:

     shell> myisamchk --recover --ft_min_word_len=3 TBL_NAME.MYI

To ensure that *Note `myisamchk': myisamchk. and the server use the
same values for full-text parameters, place each one in both the
`[mysqld]' and `[myisamchk]' sections of an option file:

     [mysqld]
     ft_min_word_len=3

     [myisamchk]
     ft_min_word_len=3

An alternative to using *Note `myisamchk': myisamchk. for index
modification is to use the *Note `REPAIR TABLE': repair-table, *Note
`ANALYZE TABLE': analyze-table, *Note `OPTIMIZE TABLE': optimize-table,
or *Note `ALTER TABLE': alter-table. statements. These statements are
performed by the server, which knows the proper full-text parameter
values to use.


File: manual.info,  Node: full-text-adding-collation,  Prev: fulltext-fine-tuning,  Up: fulltext-search

12.9.7 Adding a Collation for Full-Text Indexing
------------------------------------------------

This section describes how to add a new collation for full-text
searches. The sample collation is like `latin1_swedish_ci' but treats
the `'-'' character as a letter rather than as a punctuation character
so that it can be indexed as a word character. General information
about adding collations is given in *Note adding-collation::; it is
assumed that you have read it and are familiar with the files involved.

To add a collation for full-text indexing, use this procedure:

  1. Add a collation to the `Index.xml' file.  The collation ID must be
     unused, so choose a value different from 62 if that ID is already
     taken on your system.

          <charset name="latin1">
          ...
          <collation name="latin1_fulltext_ci" id="62"/>
          </charset>

  2. Declare the sort order for the collation in the `latin1.xml' file.
     In this case, the order can be copied from `latin1_swedish_ci':

          <collation name="latin1_fulltext_ci">
          <map>
          00 01 02 03 04 05 06 07 08 09 0A 0B 0C 0D 0E 0F
          10 11 12 13 14 15 16 17 18 19 1A 1B 1C 1D 1E 1F
          20 21 22 23 24 25 26 27 28 29 2A 2B 2C 2D 2E 2F
          30 31 32 33 34 35 36 37 38 39 3A 3B 3C 3D 3E 3F
          40 41 42 43 44 45 46 47 48 49 4A 4B 4C 4D 4E 4F
          50 51 52 53 54 55 56 57 58 59 5A 5B 5C 5D 5E 5F
          60 41 42 43 44 45 46 47 48 49 4A 4B 4C 4D 4E 4F
          50 51 52 53 54 55 56 57 58 59 5A 7B 7C 7D 7E 7F
          80 81 82 83 84 85 86 87 88 89 8A 8B 8C 8D 8E 8F
          90 91 92 93 94 95 96 97 98 99 9A 9B 9C 9D 9E 9F
          A0 A1 A2 A3 A4 A5 A6 A7 A8 A9 AA AB AC AD AE AF
          B0 B1 B2 B3 B4 B5 B6 B7 B8 B9 BA BB BC BD BE BF
          41 41 41 41 5C 5B 5C 43 45 45 45 45 49 49 49 49
          44 4E 4F 4F 4F 4F 5D D7 D8 55 55 55 59 59 DE DF
          41 41 41 41 5C 5B 5C 43 45 45 45 45 49 49 49 49
          44 4E 4F 4F 4F 4F 5D F7 D8 55 55 55 59 59 DE FF
          </map>
          </collation>

  3. Modify the `ctype' array in `latin1.xml'. Change the value
     corresponding to 0x2D (which is the code for the `'-'' character)
     from 10 (punctuation) to 01 (small letter). In the following
     array, this is the element in the fourth row down, third value
     from the end.

          <ctype>
          <map>
          00
          20 20 20 20 20 20 20 20 20 28 28 28 28 28 20 20
          20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20
          48 10 10 10 10 10 10 10 10 10 10 10 10 *01* 10 10
          84 84 84 84 84 84 84 84 84 84 10 10 10 10 10 10
          10 81 81 81 81 81 81 01 01 01 01 01 01 01 01 01
          01 01 01 01 01 01 01 01 01 01 01 10 10 10 10 10
          10 82 82 82 82 82 82 02 02 02 02 02 02 02 02 02
          02 02 02 02 02 02 02 02 02 02 02 10 10 10 10 20
          10 00 10 02 10 10 10 10 10 10 01 10 01 00 01 00
          00 10 10 10 10 10 10 10 10 10 02 10 02 00 02 01
          48 10 10 10 10 10 10 10 10 10 10 10 10 10 10 10
          10 10 10 10 10 10 10 10 10 10 10 10 10 10 10 10
          01 01 01 01 01 01 01 01 01 01 01 01 01 01 01 01
          01 01 01 01 01 01 01 10 01 01 01 01 01 01 01 02
          02 02 02 02 02 02 02 02 02 02 02 02 02 02 02 02
          02 02 02 02 02 02 02 10 02 02 02 02 02 02 02 02
          </map>
          </ctype>

  4. Restart the server.

  5. To employ the new collation, include it in the definition of
     columns that are to use it:

          mysql> DROP TABLE IF EXISTS t1;
          Query OK, 0 rows affected (0.13 sec)

          mysql> CREATE TABLE t1 (
              -> a TEXT CHARACTER SET latin1 COLLATE latin1_fulltext_ci,
              -> FULLTEXT INDEX(a)
              -> ) ENGINE=MyISAM;
          Query OK, 0 rows affected (0.47 sec)

  6. Test the collation to verify that hyphen is considered as a word
     character:

          mysql> INSERT INTO t1 VALUEs ('----'),('....'),('abcd');
          Query OK, 3 rows affected (0.22 sec)
          Records: 3  Duplicates: 0  Warnings: 0

          mysql> SELECT * FROM t1 WHERE MATCH a AGAINST ('----' IN BOOLEAN MODE);
          +------+
          | a    |
          +------+
          | ---- |
          +------+
          1 row in set (0.00 sec)


File: manual.info,  Node: cast-functions,  Next: bit-functions,  Prev: fulltext-search,  Up: functions

12.10 Cast Functions and Operators
==================================

*Cast Functions*

Name                          Description
`BINARY'                      Cast a string to a binary string
`CAST()'                      Cast a value as a certain type
`CONVERT()'                   Cast a value as a certain type

   *  `BINARY'

     The `BINARY' operator casts the string following it to a binary
     string. This is an easy way to force a column comparison to be
     done byte by byte rather than character by character. This causes
     the comparison to be case sensitive even if the column is not
     defined as *Note `BINARY': binary-varbinary. or *Note `BLOB': blob.
     `BINARY' also causes trailing spaces to be significant.

          mysql> SELECT 'a' = 'A';
                  -> 1
          mysql> SELECT BINARY 'a' = 'A';
                  -> 0
          mysql> SELECT 'a' = 'a ';
                  -> 1
          mysql> SELECT BINARY 'a' = 'a ';
                  -> 0

     In a comparison, `BINARY' affects the entire operation; it can be
     given before either operand with the same result.

     `BINARY STR' is shorthand for `CAST(STR AS BINARY)'.

     Note that in some contexts, if you cast an indexed column to
     `BINARY', MySQL is not able to use the index efficiently.

   *  `CAST(EXPR AS TYPE)'

     The `CAST()' function takes a value of one type and produce a
     value of another type, similar to `CONVERT()'. See the description
     of `CONVERT()' for more information.

   *  `CONVERT(EXPR,TYPE)', `CONVERT(EXPR USING TRANSCODING_NAME)'

     The `CONVERT()' and `CAST()' functions take a value of one type
     and produce a value of another type.

     The TYPE can be one of the following values:

        * `BINARY[(N)]'

        * `CHAR[(N)]'

        * *Note `DATE': datetime.

        * *Note `DATETIME': datetime.

        * `DECIMAL[(M[,D])]'

        * `SIGNED [INTEGER]'

        * *Note `TIME': time.

        * `UNSIGNED [INTEGER]'

     *Note `BINARY': binary-varbinary. produces a string with the *Note
     `BINARY': binary-varbinary. data type. See *Note
     binary-varbinary:: for a description of how this affects
     comparisons. If the optional length N is given, `BINARY(N)' causes
     the cast to use no more than N bytes of the argument. As of MySQL
     5.0.17, values shorter than N bytes are padded with `0x00' bytes
     to a length of N.

     `CHAR(N)' causes the cast to use no more than N characters of the
     argument.

     The *Note `DECIMAL': numeric-types. type is available as of MySQL
     5.0.8.

     `CAST()' and `CONVERT(... USING ...)' are standard SQL syntax. The
     non-`USING' form of `CONVERT()' is ODBC syntax.

     `CONVERT()' with `USING' is used to convert data between different
     character sets. In MySQL, transcoding names are the same as the
     corresponding character set names. For example, this statement
     converts the string `'abc'' in the default character set to the
     corresponding string in the `utf8' character set:

          SELECT CONVERT('abc' USING utf8);

Normally, you cannot compare a *Note `BLOB': blob.  value or other
binary string in case-insensitive fashion because binary strings have
no character set, and thus no concept of lettercase. To perform a
case-insensitive comparison, use the `CONVERT()' function to convert the
value to a nonbinary string. Comparisons of the result use the string
collation. For example, if the character set of the result has a
case-insensitive collation, a `LIKE' operation is not case sensitive:

     SELECT 'A' LIKE CONVERT(BLOB_COL USING latin1) FROM TBL_NAME;

To use a different character set, substitute its name for `latin1' in
the preceding statement. To specify a particular collation for the
converted string, use a `COLLATE' clause following the `CONVERT()'
call, as described in *Note charset-convert::. For example, to use
`latin1_german1_ci':

     SELECT 'A' LIKE CONVERT(BLOB_COL USING latin1) COLLATE latin1_german1_ci
       FROM TBL_NAME;

`CONVERT()' can be used more generally for comparing strings that are
represented in different character sets.

`LOWER()' (and `UPPER()') are ineffective when applied to binary
strings (*Note `BINARY': binary-varbinary, *Note `VARBINARY':
binary-varbinary, *Note `BLOB': blob.). To perform lettercase
conversion, convert the string to a nonbinary string:

     mysql> SET @str = BINARY 'New York';
     mysql> SELECT LOWER(@str), LOWER(CONVERT(@str USING latin1));
     +-------------+-----------------------------------+
     | LOWER(@str) | LOWER(CONVERT(@str USING latin1)) |
     +-------------+-----------------------------------+
     | New York    | new york                          |
     +-------------+-----------------------------------+

The cast functions are useful when you want to create a column with a
specific type in a *Note `CREATE TABLE ... SELECT': create-table.
statement:

     CREATE TABLE new_table SELECT CAST('2000-01-01' AS DATE);

The functions also can be useful for sorting *Note `ENUM': enum.
columns in lexical order.  Normally, sorting of *Note `ENUM': enum.
columns occurs using the internal numeric values. Casting the values to
*Note `CHAR': char. results in a lexical sort:

     SELECT ENUM_COL FROM TBL_NAME ORDER BY CAST(ENUM_COL AS CHAR);

`CAST(STR AS BINARY)' is the same thing as `BINARY STR'.  `CAST(EXPR AS
CHAR)' treats the expression as a string with the default character set.

`CAST()' also changes the result if you use it as part of a more
complex expression such as `CONCAT('Date: ',CAST(NOW() AS DATE))'.

You should not use `CAST()' to extract data in different formats but
instead use string functions like `LEFT()' or `EXTRACT()'. See *Note
date-and-time-functions::.

To cast a string to a numeric value in numeric context, you normally do
not have to do anything other than to use the string value as though it
were a number:

     mysql> SELECT 1+'1';
            -> 2

If you use a string in an arithmetic operation, it is converted to a
floating-point number during expression evaluation.

If you use a number in string context, the number automatically is
converted to a string:

     mysql> SELECT CONCAT('hello you ',2);
             -> 'hello you 2'

For information about implicit conversion of numbers to strings, see
*Note type-conversion::.

MySQL supports arithmetic with both signed and unsigned 64-bit values.
If you are using numeric operators (such as `+' or `-') and one of the
operands is an unsigned integer, the result is unsigned by default (see
*Note arithmetic-functions::). You can override this by using the
`SIGNED' or `UNSIGNED' cast operator to cast a value to a signed or
unsigned 64-bit integer, respectively.

     mysql> SELECT CAST(1-2 AS UNSIGNED)
             -> 18446744073709551615
     mysql> SELECT CAST(CAST(1-2 AS UNSIGNED) AS SIGNED);
             -> -1

If either operand is a floating-point value, the result is a
floating-point value and is not affected by the preceding rule.  (In
this context, *Note `DECIMAL': numeric-types. column values are
regarded as floating-point values.)

     mysql> SELECT CAST(1 AS UNSIGNED) - 2.0;
             -> -1.0

The SQL mode affects the result of conversion operations.  Examples:

   * If you convert a `zero' date string to a date, `CONVERT()' and
     `CAST()' return `NULL' when the `NO_ZERO_DATE' SQL mode is
     enabled. As of MySQL 5.0.4, they also produce a warning.

   * For integer subtraction, if the `NO_UNSIGNED_SUBTRACTION' SQL mode
     is enabled, the subtraction result is signed even if any operand
     is unsigned.

For more information, see *Note server-sql-mode::.


File: manual.info,  Node: bit-functions,  Next: encryption-functions,  Prev: cast-functions,  Up: functions

12.11 Bit Functions
===================

*Bitwise Functions*

Name                          Description
`BIT_COUNT()'                 Return the number of bits that are set
`&'                           Bitwise AND
`~'                           Invert bits
`|'                           Bitwise OR
`^'                           Bitwise XOR
`<<'                          Left shift
`>>'                          Right shift

MySQL uses *Note `BIGINT': numeric-types. (64-bit) arithmetic for bit
operations, so these operators have a maximum range of 64 bits.

   *  `|'

     Bitwise OR:

          mysql> SELECT 29 | 15;
                  -> 31

     The result is an unsigned 64-bit integer.

   *  `&'

     Bitwise AND:

          mysql> SELECT 29 & 15;
                  -> 13

     The result is an unsigned 64-bit integer.

   *  `^'

     Bitwise XOR:

          mysql> SELECT 1 ^ 1;
                  -> 0
          mysql> SELECT 1 ^ 0;
                  -> 1
          mysql> SELECT 11 ^ 3;
                  -> 8

     The result is an unsigned 64-bit integer.

   *  `<<'

     Shifts a longlong (*Note `BIGINT': numeric-types.)  number to the
     left.

          mysql> SELECT 1 << 2;
                  -> 4

     The result is an unsigned 64-bit integer. The value is truncated
     to 64 bits. In particular, if the shift count is greater or equal
     to the width of an unsigned 64-bit number, the result is zero.

   *  `>>'

     Shifts a longlong (*Note `BIGINT': numeric-types.)  number to the
     right.

          mysql> SELECT 4 >> 2;
                  -> 1

     The result is an unsigned 64-bit integer. The value is truncated
     to 64 bits. In particular, if the shift count is greater or equal
     to the width of an unsigned 64-bit number, the result is zero.

   *  `~'

     Invert all bits.

          mysql> SELECT 5 & ~1;
                  -> 4

     The result is an unsigned 64-bit integer.

   *  `BIT_COUNT(N)'

     Returns the number of bits that are set in the argument N.

          mysql> SELECT BIT_COUNT(29), BIT_COUNT(b'101010');
                  -> 4, 3


File: manual.info,  Node: encryption-functions,  Next: information-functions,  Prev: bit-functions,  Up: functions

12.12 Encryption and Compression Functions
==========================================

*Encryption Functions*

Name                          Description
`AES_DECRYPT()'               Decrypt using AES
`AES_ENCRYPT()'               Encrypt using AES
`COMPRESS()'                  Return result as a binary string
`DECODE()'                    Decodes a string encrypted using ENCODE()
`DES_DECRYPT()'               Decrypt a string
`DES_ENCRYPT()'               Encrypt a string
`ENCODE()'                    Encode a string
`ENCRYPT()'                   Encrypt a string
`MD5()'                       Calculate MD5 checksum
`OLD_PASSWORD()'              Return the value of the  pre-4.1
                              implementation of PASSWORD
`PASSWORD()'                  Calculate and return a password string
`SHA1()', `SHA()'             Calculate an SHA-1 160-bit checksum
`UNCOMPRESS()'                Uncompress a string compressed
`UNCOMPRESSED_LENGTH()'       Return the length of a string before
                              compression

Many encryption and compression functions return strings for which the
result might contain arbitrary byte values. If you want to store these
results, use a column with a *Note `VARBINARY': binary-varbinary. or
*Note `BLOB': blob. binary string data type. This will avoid potential
problems with trailing space removal or character set conversion that
would change data values, such as may occur if you use a nonbinary
string data type (*Note `CHAR': char, *Note `VARCHAR': char, *Note
`TEXT': blob.).

For functions such as `MD5()' or `SHA1()' that return a string of hex
digits, the return value cannot be converted to uppercase or compared in
case-insensitive fashion as is. You must convert the value to a
nonbinary string. See the discussion of binary string conversion in
*Note cast-functions::.

If an application stores values from a function such as `MD5()' or
`SHA1()' that returns a string of hex digits, more efficient storage
and comparisons can be obtained by converting the hex representation to
binary using `UNHEX()' and storing the result in a *Note `BINARY(N)':
binary-varbinary.  column. Each pair of hex digits requires one byte in
binary form, so the value of N depends on the length of the hex string.
N is 16 for an `MD5()' value and 20 for a `SHA1()' value.

The size penalty for storing the hex string in a *Note `CHAR': char.
column is at least two times, up to six times if the value is stored in
a column that uses the `utf8' character set (where each character uses 3
bytes). Storing the string also results in slower comparisons because
of the larger values and the need to take character set collation rules
into account.

Suppose that an application stores `MD5()' string values in a *Note
`CHAR(32)': char. column:

     CREATE TABLE md5_tbl (md5_val CHAR(32), ...);
     INSERT INTO md5_tbl (md5_val, ...) VALUES(MD5('abcdef'), ...);

To convert hex strings to more compact form, modify the application to
use `UNHEX()' and *Note `BINARY(16)': binary-varbinary. instead as
follows:

     CREATE TABLE md5_tbl (md5_val BINARY(16), ...);
     INSERT INTO md5_tbl (md5_val, ...) VALUES(UNHEX(MD5('abcdef')), ...);

Applications should be prepared to handle the very rare case that a
hashing function produces the same value for two different input
values. One way to make collisions detectable is to make the hash
column a primary key.

*Note*:

Exploits for the MD5 and SHA-1 algorithms have become known. You may
wish to consider using one of the other encryption functions described
in this section instead.

*Caution*:

Passwords or other sensitive values supplied as arguments to encryption
functions are sent in plaintext to the MySQL server unless an SSL
connection is used. Also, such values will appear in any MySQL logs to
which they are written. To avoid these types of exposure, applications
can encrypt sensitive values on the client side before sending them to
the server. The same considerations apply to encryption keys. To avoid
exposing these, applications can use stored procedures to encrypt and
decrypt values on the server side.

   *  `AES_DECRYPT(CRYPT_STR,KEY_STR)'

     This function decrypts data using the official AES (Advanced
     Encryption Standard) algorithm. For more information, see the
     description of `AES_ENCRYPT()'.

   *  `AES_ENCRYPT(STR,KEY_STR)'

     `AES_ENCRYPT()' and `AES_DECRYPT()' enable encryption and
     decryption of data using the official AES (Advanced Encryption
     Standard) algorithm, previously known as `Rijndael.' Encoding with
     a 128-bit key length is used, but you can extend it up to 256 bits
     by modifying the source. We chose 128 bits because it is much
     faster and it is secure enough for most purposes.

     `AES_ENCRYPT()' encrypts a string and returns a binary string.
     `AES_DECRYPT()' decrypts the encrypted string and returns the
     original string. The input arguments may be any length. If either
     argument is `NULL', the result of this function is also `NULL'.

     Because AES is a block-level algorithm, padding is used to encode
     uneven length strings and so the result string length may be
     calculated using this formula:

          16 * (trunc(STRING_LENGTH / 16) + 1)

     If `AES_DECRYPT()' detects invalid data or incorrect padding, it
     returns `NULL'. However, it is possible for `AES_DECRYPT()' to
     return a non-`NULL' value (possibly garbage) if the input data or
     the key is invalid.

     You can use the AES functions to store data in an encrypted form
     by modifying your queries:

          INSERT INTO t VALUES (1,AES_ENCRYPT('text','password'));

     `AES_ENCRYPT()' and `AES_DECRYPT()' can be considered the most
     cryptographically secure encryption functions currently available
     in MySQL.

   *  `COMPRESS(STRING_TO_COMPRESS)'

     Compresses a string and returns the result as a binary string.
     This function requires MySQL to have been compiled with a
     compression library such as `zlib'.  Otherwise, the return value
     is always `NULL'.  The compressed string can be uncompressed with
     `UNCOMPRESS()'.

          mysql> SELECT LENGTH(COMPRESS(REPEAT('a',1000)));
                  -> 21
          mysql> SELECT LENGTH(COMPRESS(''));
                  -> 0
          mysql> SELECT LENGTH(COMPRESS('a'));
                  -> 13
          mysql> SELECT LENGTH(COMPRESS(REPEAT('a',16)));
                  -> 15

     The compressed string contents are stored the following way:

        * Empty strings are stored as empty strings.

        * Nonempty strings are stored as a four-byte length of the
          uncompressed string (low byte first), followed by the
          compressed string. If the string ends with space, an extra
          ``.'' character is added to avoid problems with endspace
          trimming should the result be stored in a *Note `CHAR': char.
          or *Note `VARCHAR': char. column. (However, use of nonbinary
          string data types such as *Note `CHAR': char. or *Note
          `VARCHAR': char. to store compressed strings is not
          recommended anyway because character set conversion may
          occur. Use a *Note `VARBINARY': binary-varbinary. or *Note
          `BLOB': blob. binary string column instead.)

   *  `DECODE(CRYPT_STR,PASS_STR)'

     Decrypts the encrypted string CRYPT_STR using PASS_STR as the
     password.  CRYPT_STR should be a string returned from `ENCODE()'.

   *  `DES_DECRYPT(CRYPT_STR[,KEY_STR])'

     Decrypts a string encrypted with `DES_ENCRYPT()'. If an error
     occurs, this function returns `NULL'.

     This function works only if MySQL has been configured with SSL
     support. See *Note secure-connections::.

     If no KEY_STR argument is given, `DES_DECRYPT()' examines the
     first byte of the encrypted string to determine the DES key number
     that was used to encrypt the original string, and then reads the
     key from the DES key file to decrypt the message.  For this to
     work, the user must have the `SUPER' privilege. The key file can
     be specified with the `--des-key-file' server option.

     If you pass this function a KEY_STR argument, that string is used
     as the key for decrypting the message.

     If the CRYPT_STR argument does not appear to be an encrypted
     string, MySQL returns the given CRYPT_STR.

   *  `DES_ENCRYPT(STR[,{KEY_NUM|KEY_STR}])'

     Encrypts the string with the given key using the Triple-DES
     algorithm.

     This function works only if MySQL has been configured with SSL
     support. See *Note secure-connections::.

     The encryption key to use is chosen based on the second argument
     to `DES_ENCRYPT()', if one was given. With no argument, the first
     key from the DES key file is used. With a KEY_NUM argument, the
     given key number (0 to 9) from the DES key file is used. With a
     KEY_STR argument, the given key string is used to encrypt STR.

     The key file can be specified with the `--des-key-file' server
     option.

     The return string is a binary string where the first character is
     `CHAR(128 | KEY_NUM)'. If an error occurs, `DES_ENCRYPT()' returns
     `NULL'.

     The 128 is added to make it easier to recognize an encrypted key.
     If you use a string key, KEY_NUM is 127.

     The string length for the result is given by this formula:

          NEW_LEN = ORIG_LEN + (8 - (ORIG_LEN % 8)) + 1

     Each line in the DES key file has the following format:

          KEY_NUM DES_KEY_STR

     Each KEY_NUM value must be a number in the range from `0' to `9'.
     Lines in the file may be in any order.  DES_KEY_STR is the string
     that is used to encrypt the message. There should be at least one
     space between the number and the key. The first key is the default
     key that is used if you do not specify any key argument to
     `DES_ENCRYPT()'.

     You can tell MySQL to read new key values from the key file with
     the *Note `FLUSH DES_KEY_FILE': flush. statement. This requires the
     `RELOAD' privilege.

     One benefit of having a set of default keys is that it gives
     applications a way to check for the existence of encrypted column
     values, without giving the end user the right to decrypt those
     values.

          mysql> SELECT customer_address FROM customer_table
               > WHERE crypted_credit_card = DES_ENCRYPT('credit_card_number');

   *  `ENCODE(STR,PASS_STR)'

     Encrypt STR using PASS_STR as the password. To decrypt the result,
     use `DECODE()'.

     The result is a binary string of the same length as STR.

     The strength of the encryption is based on how good the random
     generator is. It should suffice for short strings.

   *  `ENCRYPT(STR[,SALT])'

     Encrypts STR using the Unix `crypt()' system call and returns a
     binary string. The SALT argument must be a string with at least
     two characters or the result will be `NULL'. If no SALT argument
     is given, a random value is used.

          mysql> SELECT ENCRYPT('hello');
                  -> 'VxuFAJXVARROc'

     `ENCRYPT()' ignores all but the first eight characters of STR, at
     least on some systems. This behavior is determined by the
     implementation of the underlying `crypt()' system call.

     The use of `ENCRYPT()' with the `ucs2' multi-byte character set is
     not recommended because the system call expects a string
     terminated by a zero byte.

     If `crypt()' is not available on your system (as is the case with
     Windows), `ENCRYPT()' always returns `NULL'.

   *  `MD5(STR)'

     Calculates an MD5 128-bit checksum for the string. The value is
     returned as a binary string of 32 hex digits, or `NULL' if the
     argument was `NULL'. The return value can, for example, be used as
     a hash key. See the notes at the beginning of this section about
     storing hash values efficiently.

          mysql> SELECT MD5('testing');
                  -> 'ae2b1fca515949e5d54fb22b8ed95575'

     This is the `RSA Data Security, Inc. MD5 Message-Digest Algorithm.'

     See the note regarding the MD5 algorithm at the beginning this
     section.

   *  `OLD_PASSWORD(STR)'

     `OLD_PASSWORD()' was added when the implementation of `PASSWORD()'
     was changed in MySQL 4.1 to improve security.  `OLD_PASSWORD()'
     returns the value of the pre-4.1 implementation of `PASSWORD()' as
     a binary string, and is intended to permit you to reset passwords
     for any pre-4.1 clients that need to connect to your version 5.0
     MySQL server without locking them out. See *Note
     password-hashing::.

   *  `PASSWORD(STR)'

     Calculates and returns a password string from the plaintext
     password STR and returns a binary string, or `NULL' if the
     argument was `NULL'. This is the function that is used for
     encrypting MySQL passwords for storage in the `Password' column of
     the `user' grant table.

          mysql> SELECT PASSWORD('badpwd');
                  -> '*AAB3E285149C0135D51A520E1940DD3263DC008C'

     `PASSWORD()' encryption is one-way (not reversible).

     `PASSWORD()' does not perform password encryption in the same way
     that Unix passwords are encrypted. See `ENCRYPT()'.

     *Note*:

     The `PASSWORD()' function is used by the authentication system in
     MySQL Server; you should _not_ use it in your own applications.
     For that purpose, consider `MD5()' or `SHA1()' instead. Also see
     section 2 (Challenge-Response Authentication Mechanism (CRAM)),
     for more information about handling passwords and authentication
     securely in your applications.

     *Important*:

     Statements that invoke `PASSWORD()' may be recorded in server logs
     or in a history file such as `~/.mysql_history', which means that
     plaintext passwords may be read by anyone having read access to
     that information. See *Note password-security::.

   *  `SHA1(STR)', `SHA(STR)'

     Calculates an SHA-1 160-bit checksum for the string, as described
     in RFC 3174 (Secure Hash Algorithm). The value is returned as a
     binary string of 40 hex digits, or `NULL' if the argument was
     `NULL'. One of the possible uses for this function is as a hash
     key. See the notes at the beginning of this section about storing
     hash values efficiently. You can also use `SHA1()' as a
     cryptographic function for storing passwords.  `SHA()' is
     synonymous with `SHA1()'.

          mysql> SELECT SHA1('abc');
                  -> 'a9993e364706816aba3e25717850c26c9cd0d89d'

     `SHA1()' can be considered a cryptographically more secure
     equivalent of `MD5()'. However, see the note regarding the MD5 and
     SHA-1 algorithms at the beginning this section.

   *  `UNCOMPRESS(STRING_TO_UNCOMPRESS)'

     Uncompresses a string compressed by the `COMPRESS()' function. If
     the argument is not a compressed value, the result is `NULL'. This
     function requires MySQL to have been compiled with a compression
     library such as `zlib'. Otherwise, the return value is always
     `NULL'.

          mysql> SELECT UNCOMPRESS(COMPRESS('any string'));
                  -> 'any string'
          mysql> SELECT UNCOMPRESS('any string');
                  -> NULL

   *  `UNCOMPRESSED_LENGTH(COMPRESSED_STRING)'

     Returns the length that the compressed string had before being
     compressed.

          mysql> SELECT UNCOMPRESSED_LENGTH(COMPRESS(REPEAT('a',30)));
                  -> 30


File: manual.info,  Node: information-functions,  Next: miscellaneous-functions,  Prev: encryption-functions,  Up: functions

12.13 Information Functions
===========================

*Information Functions*

Name                          Description
`BENCHMARK()'                 Repeatedly execute an expression
`CHARSET()'                   Return the character set of the argument
`COERCIBILITY()'              Return the collation coercibility value of
                              the string  argument
`COLLATION()'                 Return the collation of the string argument
`CONNECTION_ID()'             Return the connection ID (thread ID)  for
                              the connection
`CURRENT_USER()',             The authenticated user name and host name
`CURRENT_USER'                
`DATABASE()'                  Return the default (current) database name
`FOUND_ROWS()'                For a SELECT with a LIMIT clause, the
                              number of rows that would be returned were
                              there no LIMIT clause
`LAST_INSERT_ID()'            Value of the AUTOINCREMENT column  for the
                              last INSERT
`ROW_COUNT()'                 The number of rows  updated
`SCHEMA()'                    A synonym for DATABASE()
`SESSION_USER()'              Synonym for USER()
`SYSTEM_USER()'               Synonym for USER()
`USER()'                      The user name and host name provided by
                              the client
`VERSION()'                   Returns a string that indicates the MySQL
                              server version

   *  `BENCHMARK(COUNT,EXPR)'

     The `BENCHMARK()' function executes the expression EXPR repeatedly
     COUNT times. It may be used to time how quickly MySQL processes
     the expression. The result value is always `0'. The intended use
     is from within the *Note `mysql': mysql. client, which reports
     query execution times:

          mysql> SELECT BENCHMARK(1000000,ENCODE('hello','goodbye'));
          +----------------------------------------------+
          | BENCHMARK(1000000,ENCODE('hello','goodbye')) |
          +----------------------------------------------+
          |                                            0 |
          +----------------------------------------------+
          1 row in set (4.74 sec)

     The time reported is elapsed time on the client end, not CPU time
     on the server end. It is advisable to execute `BENCHMARK()'
     several times, and to interpret the result with regard to how
     heavily loaded the server machine is.

     `BENCHMARK()' is intended for measuring the runtime performance of
     scalar expressions, which has some significant implications for
     the way that you use it and interpret the results:

        * Only scalar expressions can be used. Although the expression
          can be a subquery, it must return a single column and at most
          a single row. For example, `BENCHMARK(10, (SELECT * FROM t))'
          will fail if the table `t' has more than one column or more
          than one row.

        * Executing a `SELECT EXPR' statement N times differs from
          executing `SELECT BENCHMARK(N, EXPR)' in terms of the amount
          of overhead involved. The two have very different execution
          profiles and you should not expect them to take the same
          amount of time. The former involves the parser, optimizer,
          table locking, and runtime evaluation N times each. The latter
          involves only runtime evaluation N times, and all the other
          components just once. Memory structures already allocated are
          reused, and runtime optimizations such as local caching of
          results already evaluated for aggregate functions can alter
          the results. Use of `BENCHMARK()' thus measures performance
          of the runtime component by giving more weight to that
          component and removing the `noise' introduced by the network,
          parser, optimizer, and so forth.

   *  `CHARSET(STR)'

     Returns the character set of the string argument.

          mysql> SELECT CHARSET('abc');
                  -> 'latin1'
          mysql> SELECT CHARSET(CONVERT('abc' USING utf8));
                  -> 'utf8'
          mysql> SELECT CHARSET(USER());
                  -> 'utf8'

   *  `COERCIBILITY(STR)'

     Returns the collation coercibility value of the string argument.

          mysql> SELECT COERCIBILITY('abc' COLLATE latin1_swedish_ci);
                  -> 0
          mysql> SELECT COERCIBILITY(USER());
                  -> 3
          mysql> SELECT COERCIBILITY('abc');
                  -> 4

     The return values have the meanings shown in the following table.
     Lower values have higher precedence.

     CoercibilityMeaning    Example
     `0'        Explicit   Value with `COLLATE' clause
                collation  
     `1'        No         Concatenation of strings with different
                collation  collations
     `2'        Implicit   Column value
                collation  
     `3'        System     `USER()' return value
                constant   
     `4'        Coercible  Literal string
     `5'        Ignorable  `NULL' or an expression derived from `NULL'

     Before MySQL 5.0.3, the return values are shown as follows, and
     functions such as `USER()' have a coercibility of 2:

     CoercibilityMeaning    Example
     `0'        Explicit   Value with `COLLATE' clause
                collation  
     `1'        No         Concatenation of strings with different
                collation  collations
     `2'        Implicit   Column value, stored routine parameter or
                collation  local variable
     `3'        Coercible  Literal string

   *  `COLLATION(STR)'

     Returns the collation of the string argument.

          mysql> SELECT COLLATION('abc');
                  -> 'latin1_swedish_ci'
          mysql> SELECT COLLATION(_utf8'abc');
                  -> 'utf8_general_ci'

   *  `CONNECTION_ID()'

     Returns the connection ID (thread ID) for the connection.  Every
     connection has an ID that is unique among the set of currently
     connected clients.

          mysql> SELECT CONNECTION_ID();
                  -> 23786

   *  `CURRENT_USER', `CURRENT_USER()'

     Returns the user name and host name combination for the MySQL
     account that the server used to authenticate the current client.
     This account determines your access privileges. The return value
     is a string in the `utf8' character set.

     The value of `CURRENT_USER()' can differ from the value of
     `USER()'.

          mysql> SELECT USER();
                  -> 'davida@localhost'
          mysql> SELECT * FROM mysql.user;
          ERROR 1044: Access denied for user ''@'localhost' to
          database 'mysql'
          mysql> SELECT CURRENT_USER();
                  -> '@localhost'

     The example illustrates that although the client specified a user
     name of `davida' (as indicated by the value of the `USER()'
     function), the server authenticated the client using an anonymous
     user account (as seen by the empty user name part of the
     `CURRENT_USER()' value). One way this might occur is that there is
     no account listed in the grant tables for `davida'.

     Within a stored program or view, `CURRENT_USER()' returns the
     account for the user who defined the object (as given by its
     `DEFINER' value). This applies to stored programs as of MySQL
     5.0.10 and to views as of MySQL 5.0.24.  (For older versions,
     `CURRENT_USER()' returns the account for the object's invoker.)
     For stored procedures and functions and views defined with the
     `SQL SECURITY INVOKER' characteristic, `CURRENT_USER()' returns the
     object's invoker.

   *  `DATABASE()'

     Returns the default (current) database name as a string in the
     `utf8' character set. If there is no default database,
     `DATABASE()' returns `NULL'. Within a stored routine, the default
     database is the database that the routine is associated with,
     which is not necessarily the same as the database that is the
     default in the calling context.

          mysql> SELECT DATABASE();
                  -> 'test'

   *  `FOUND_ROWS()'

     A *Note `SELECT': select. statement may include a `LIMIT' clause
     to restrict the number of rows the server returns to the client.
     In some cases, it is desirable to know how many rows the statement
     would have returned without the `LIMIT', but without running the
     statement again. To obtain this row count, include a
     `SQL_CALC_FOUND_ROWS' option in the *Note `SELECT': select.
     statement, and then invoke `FOUND_ROWS()' afterward:

          mysql> SELECT SQL_CALC_FOUND_ROWS * FROM TBL_NAME
              -> WHERE id > 100 LIMIT 10;
          mysql> SELECT FOUND_ROWS();

     The second *Note `SELECT': select. returns a number indicating how
     many rows the first *Note `SELECT': select. would have returned had
     it been written without the `LIMIT' clause.

     In the absence of the `SQL_CALC_FOUND_ROWS' option in the most
     recent successful *Note `SELECT': select. statement,
     `FOUND_ROWS()' returns the number of rows in the result set
     returned by that statement. If the statement includes a `LIMIT'
     clause, `FOUND_ROWS()' returns the number of rows up to the limit.
     For example, `FOUND_ROWS()' returns 10 or 60, respectively, if the
     statement includes `LIMIT 10' or `LIMIT 50, 10'.

     The row count available through `FOUND_ROWS()' is transient and
     not intended to be available past the statement following the
     `SELECT SQL_CALC_FOUND_ROWS' statement. If you need to refer to
     the value later, save it:

          mysql> SELECT SQL_CALC_FOUND_ROWS * FROM ... ;
          mysql> SET @rows = FOUND_ROWS();

     If you are using `SELECT SQL_CALC_FOUND_ROWS', MySQL must
     calculate how many rows are in the full result set. However, this
     is faster than running the query again without `LIMIT', because
     the result set need not be sent to the client.

     `SQL_CALC_FOUND_ROWS' and `FOUND_ROWS()' can be useful in
     situations when you want to restrict the number of rows that a
     query returns, but also determine the number of rows in the full
     result set without running the query again. An example is a Web
     script that presents a paged display containing links to the pages
     that show other sections of a search result. Using `FOUND_ROWS()'
     enables you to determine how many other pages are needed for the
     rest of the result.

     The use of `SQL_CALC_FOUND_ROWS' and `FOUND_ROWS()' is more complex
     for *Note `UNION': union. statements than for simple *Note
     `SELECT': select. statements, because `LIMIT' may occur at
     multiple places in a *Note `UNION': union. It may be applied to
     individual *Note `SELECT': select. statements in the *Note
     `UNION': union, or global to the *Note `UNION': union. result as a
     whole.

     The intent of `SQL_CALC_FOUND_ROWS' for *Note `UNION': union. is
     that it should return the row count that would be returned without
     a global `LIMIT'. The conditions for use of `SQL_CALC_FOUND_ROWS'
     with *Note `UNION': union. are:

        * The `SQL_CALC_FOUND_ROWS' keyword must appear in the first
          *Note `SELECT': select.  of the *Note `UNION': union.

        * The value of `FOUND_ROWS()' is exact only if *Note `UNION
          ALL': union.  is used. If *Note `UNION': union. without `ALL'
          is used, duplicate removal occurs and the value of
          `FOUND_ROWS()' is only approximate.

        * If no `LIMIT' is present in the *Note `UNION': union,
          `SQL_CALC_FOUND_ROWS' is ignored and returns the number of
          rows in the temporary table that is created to process the
          *Note `UNION': union.

     Beyond the cases described here, the behavior of `FOUND_ROWS()' is
     undefined (for example, its value following a *Note `SELECT':
     select. statement that fails with an error).

     *Important*:

     `FOUND_ROWS()' is not replicated reliably, and should not be used
     with databases that are to be replicated.

   *  `LAST_INSERT_ID()', `LAST_INSERT_ID(EXPR)'

     `LAST_INSERT_ID()' (with no argument) returns the _first_
     automatically generated value that was set for an `AUTO_INCREMENT'
     column by the _most recently executed_ *Note `INSERT': insert.
     statement to affect such a column. For example, after inserting a
     row that generates an `AUTO_INCREMENT' value, you can get the value
     like this:

          mysql> SELECT LAST_INSERT_ID();
                  -> 195

     if a table contains an `AUTO_INCREMENT' column and *Note `INSERT
     ... ON DUPLICATE KEY UPDATE': insert-on-duplicate. updates (rather
     than inserts) a row, the value of `LAST_INSERT_ID()' is not
     meaningful. For a workaround, see *Note insert-on-duplicate::.

     The currently executing statement does not affect the value of
     `LAST_INSERT_ID()'. Suppose that you generate an `AUTO_INCREMENT'
     value with one statement, and then refer to `LAST_INSERT_ID()' in a
     multiple-row *Note `INSERT': insert. statement that inserts rows
     into a table with its own `AUTO_INCREMENT' column. The value of
     `LAST_INSERT_ID()' will remain stable in the second statement; its
     value for the second and later rows is not affected by the earlier
     row insertions.  (However, if you mix references to
     `LAST_INSERT_ID()' and `LAST_INSERT_ID(EXPR)', the effect is
     undefined.)

     If the previous statement returned an error, the value of
     `LAST_INSERT_ID()' is undefined.  For transactional tables, if the
     statement is rolled back due to an error, the value of
     `LAST_INSERT_ID()' is left undefined. For manual *Note `ROLLBACK':
     commit, the value of `LAST_INSERT_ID()' is not restored to that
     before the transaction; it remains as it was at the point of the
     *Note `ROLLBACK': commit.

     Within the body of a stored routine (procedure or function) or a
     trigger, the value of `LAST_INSERT_ID()' changes the same way as
     for statements executed outside the body of these kinds of
     objects. The effect of a stored routine or trigger upon the value
     of `LAST_INSERT_ID()' that is seen by following statements depends
     on the kind of routine:

        * If a stored procedure executes statements that change the
          value of `LAST_INSERT_ID()', the changed value is seen by
          statements that follow the procedure call.

        * For stored functions and triggers that change the value, the
          value is restored when the function or trigger ends, so
          following statements do not see a changed value.  (Before
          MySQL 5.0.12, the value is not restored and following
          statements do see a changed value.)

     The ID that was generated is maintained in the server on a
     _per-connection basis_. This means that the value returned by the
     function to a given client is the first `AUTO_INCREMENT' value
     generated for most recent statement affecting an `AUTO_INCREMENT'
     column _by that client_. This value cannot be affected by other
     clients, even if they generate `AUTO_INCREMENT' values of their
     own. This behavior ensures that each client can retrieve its own ID
     without concern for the activity of other clients, and without the
     need for locks or transactions.

     The value of `LAST_INSERT_ID()' is not changed if you set the
     `AUTO_INCREMENT' column of a row to a non-`magic' value (that is,
     a value that is not `NULL' and not `0').

     *Important*:

     If you insert multiple rows using a single *Note `INSERT': insert.
     statement, `LAST_INSERT_ID()' returns the value generated for the
     _first_ inserted row _only_. The reason for this is to make it
     possible to reproduce easily the same *Note `INSERT': insert.
     statement against some other server.

     For example:

          mysql> USE test;
          Database changed
          mysql> CREATE TABLE t (
              ->   id INT AUTO_INCREMENT NOT NULL PRIMARY KEY,
              ->   name VARCHAR(10) NOT NULL
              -> );
          Query OK, 0 rows affected (0.09 sec)

          mysql> INSERT INTO t VALUES (NULL, 'Bob');
          Query OK, 1 row affected (0.01 sec)

          mysql> SELECT * FROM t;
          +----+------+
          | id | name |
          +----+------+
          |  1 | Bob  |
          +----+------+
          1 row in set (0.01 sec)

          mysql> SELECT LAST_INSERT_ID();
          +------------------+
          | LAST_INSERT_ID() |
          +------------------+
          |                1 |
          +------------------+
          1 row in set (0.00 sec)

          mysql> INSERT INTO t VALUES
              -> (NULL, 'Mary'), (NULL, 'Jane'), (NULL, 'Lisa');
          Query OK, 3 rows affected (0.00 sec)
          Records: 3  Duplicates: 0  Warnings: 0

          mysql> SELECT * FROM t;
          +----+------+
          | id | name |
          +----+------+
          |  1 | Bob  |
          |  2 | Mary |
          |  3 | Jane |
          |  4 | Lisa |
          +----+------+
          4 rows in set (0.01 sec)

          mysql> SELECT LAST_INSERT_ID();
          +------------------+
          | LAST_INSERT_ID() |
          +------------------+
          |                2 |
          +------------------+
          1 row in set (0.00 sec)

     Although the second *Note `INSERT': insert.  statement inserted
     three new rows into `t', the ID generated for the first of these
     rows was `2', and it is this value that is returned by
     `LAST_INSERT_ID()' for the following *Note `SELECT': select.
     statement.

     If you use *Note `INSERT IGNORE': insert. and the row is ignored,
     the `AUTO_INCREMENT' counter is not incremented and
     `LAST_INSERT_ID()' returns `0', which reflects that no row was
     inserted.

     If EXPR is given as an argument to `LAST_INSERT_ID()', the value of
     the argument is returned by the function and is remembered as the
     next value to be returned by `LAST_INSERT_ID()'. This can be used
     to simulate sequences:

       1. Create a table to hold the sequence counter and initialize it:

               mysql> CREATE TABLE sequence (id INT NOT NULL);
               mysql> INSERT INTO sequence VALUES (0);

       2. Use the table to generate sequence numbers like this:

               mysql> UPDATE sequence SET id=LAST_INSERT_ID(id+1);
               mysql> SELECT LAST_INSERT_ID();

          The *Note `UPDATE': update. statement increments the sequence
          counter and causes the next call to `LAST_INSERT_ID()' to
          return the updated value. The *Note `SELECT': select.
          statement retrieves that value. The *Note
          `mysql_insert_id()': mysql-insert-id. C API function can also
          be used to get the value. See *Note mysql-insert-id::.

     You can generate sequences without calling `LAST_INSERT_ID()', but
     the utility of using the function this way is that the ID value is
     maintained in the server as the last automatically generated
     value. It is multi-user safe because multiple clients can issue
     the *Note `UPDATE': update. statement and get their own sequence
     value with the *Note `SELECT': select. statement (or *Note
     `mysql_insert_id()': mysql-insert-id.), without affecting or being
     affected by other clients that generate their own sequence values.

     Note that *Note `mysql_insert_id()': mysql-insert-id. is only
     updated after *Note `INSERT': insert. and *Note `UPDATE': update.
     statements, so you cannot use the C API function to retrieve the
     value for `LAST_INSERT_ID(EXPR)' after executing other SQL
     statements like *Note `SELECT': select. or *Note `SET': set-option.

   *  `ROW_COUNT()'

     `ROW_COUNT()' returns the number of rows changed, deleted, or
     inserted by the last statement if it was an *Note `UPDATE': update,
     *Note `DELETE': delete, or *Note `INSERT': insert. For other
     statements, the value may not be meaningful.

     For *Note `UPDATE': update. statements, the affected-rows value by
     default is the number of rows actually changed. If you specify the
     `CLIENT_FOUND_ROWS' flag to *Note `mysql_real_connect()':
     mysql-real-connect. when connecting to *Note `mysqld': mysqld, the
     affected-rows value is the number of rows `found'; that is,
     matched by the `WHERE' clause.

     For *Note `REPLACE': replace. statements, the affected-rows value
     is 2 if the new row replaced an old row, because in this case, one
     row was inserted after the duplicate was deleted.

     For *Note `INSERT ... ON DUPLICATE KEY UPDATE':
     insert-on-duplicate. statements, the affected-rows value is 1 if
     the row is inserted as a new row and 2 if an existing row is
     updated.

     The `ROW_COUNT()' value is similar to the value from the *Note
     `mysql_affected_rows()': mysql-affected-rows. C API function and
     the row count that the *Note `mysql': mysql.  client displays
     following statement execution.

          mysql> INSERT INTO t VALUES(1),(2),(3);
          Query OK, 3 rows affected (0.00 sec)
          Records: 3  Duplicates: 0  Warnings: 0

          mysql> SELECT ROW_COUNT();
          +-------------+
          | ROW_COUNT() |
          +-------------+
          |           3 |
          +-------------+
          1 row in set (0.00 sec)

          mysql> DELETE FROM t WHERE i IN(1,2);
          Query OK, 2 rows affected (0.00 sec)

          mysql> SELECT ROW_COUNT();
          +-------------+
          | ROW_COUNT() |
          +-------------+
          |           2 |
          +-------------+
          1 row in set (0.00 sec)

     `ROW_COUNT()' was added in MySQL 5.0.1.

     *Important*:

     `ROW_COUNT()' is not replicated reliably.

   *  `SCHEMA()'

     This function is a synonym for `DATABASE()'. It was added in MySQL
     5.0.2.

   *  `SESSION_USER()'

     `SESSION_USER()' is a synonym for `USER()'.

   *  `SYSTEM_USER()'

     `SYSTEM_USER()' is a synonym for `USER()'.

   *  `USER()'

     Returns the current MySQL user name and host name as a string in
     the `utf8' character set.

          mysql> SELECT USER();
                  -> 'davida@localhost'

     The value indicates the user name you specified when connecting to
     the server, and the client host from which you connected. The
     value can be different from that of `CURRENT_USER()'.

     You can extract only the user name part like this:

          mysql> SELECT SUBSTRING_INDEX(USER(),'@',1);
                  -> 'davida'

   *  `VERSION()'

     Returns a string that indicates the MySQL server version. The
     string uses the `utf8' character set. The value might have a
     suffix in addition to the version number.  See the description of
     the `version' system variable in *Note server-system-variables::.

          mysql> SELECT VERSION();
                  -> '5.0.95-standard'


File: manual.info,  Node: miscellaneous-functions,  Next: group-by-functions-and-modifiers,  Prev: information-functions,  Up: functions

12.14 Miscellaneous Functions
=============================

*Miscellaneous Functions*

Name                          Description
`DEFAULT()'                   Return the default value for a table column
`GET_LOCK()'                  Get a named lock
`INET_ATON()'                 Return the numeric value of an IP address
`INET_NTOA()'                 Return the IP address from a numeric value
`IS_FREE_LOCK()'              Checks whether the named lock  is free
`IS_USED_LOCK()'              Checks whether the named lock is in use.
                              Return connection identifier if true.
`MASTER_POS_WAIT()'           Block until the slave has read and
                              applied all updates up to the specified
                              position
`NAME_CONST()'                Causes the column to have the given name
`RAND()'                      Return a random floating-point value
`RELEASE_LOCK()'              Releases the named lock
`SLEEP()'                     Sleep for a number of seconds
`UUID()'                      Return a Universal Unique Identifier (UUID)
`VALUES()'                    Defines the values to be used during an
                              INSERT

   *  `DEFAULT(COL_NAME)'

     Returns the default value for a table column. Starting with MySQL
     5.0.2, an error results if the column has no default value.

          mysql> UPDATE t SET i = DEFAULT(i)+1 WHERE id < 100;

   * `FORMAT(X,D)'

     Formats the number X to a format like `'#,###,###.##'', rounded to
     D decimal places, and returns the result as a string. For details,
     see *Note string-functions::.

   *  `GET_LOCK(STR,TIMEOUT)'

     Tries to obtain a lock with a name given by the string STR, using
     a timeout of TIMEOUT seconds. Returns `1' if the lock was obtained
     successfully, `0' if the attempt timed out (for example, because
     another client has previously locked the name), or `NULL' if an
     error occurred (such as running out of memory or the thread was
     killed with *Note `mysqladmin kill': mysqladmin.). If you have a
     lock obtained with `GET_LOCK()', it is released when you execute
     `RELEASE_LOCK()', execute a new `GET_LOCK()', or your connection
     terminates (either normally or abnormally). Locks obtained with
     `GET_LOCK()' do not interact with transactions. That is,
     committing a transaction does not release any such locks obtained
     during the transaction.

     This function can be used to implement application locks or to
     simulate record locks. Names are locked on a server-wide basis. If
     a name has been locked by one client, `GET_LOCK()' blocks any
     request by another client for a lock with the same name. This
     enables clients that agree on a given lock name to use the name to
     perform cooperative advisory locking. But be aware that it also
     enables a client that is not among the set of cooperating clients
     to lock a name, either inadvertently or deliberately, and thus
     prevent any of the cooperating clients from locking that name. One
     way to reduce the likelihood of this is to use lock names that are
     database-specific or application-specific.  For example, use lock
     names of the form DB_NAME.STR or APP_NAME.STR.

          mysql> SELECT GET_LOCK('lock1',10);
                  -> 1
          mysql> SELECT IS_FREE_LOCK('lock2');
                  -> 1
          mysql> SELECT GET_LOCK('lock2',10);
                  -> 1
          mysql> SELECT RELEASE_LOCK('lock2');
                  -> 1
          mysql> SELECT RELEASE_LOCK('lock1');
                  -> NULL

     The second `RELEASE_LOCK()' call returns `NULL' because the lock
     `'lock1'' was automatically released by the second `GET_LOCK()'
     call.

     If multiple clients are waiting for a lock, the order in which
     they will acquire it is undefined and depends on factors such as
     the thread library in use. In particular, applications should not
     assume that clients will acquire the lock in the same order that
     they issued the lock requests.

     *Note*:

     If a client attempts to acquire a lock that is already held by
     another client, it blocks according to the TIMEOUT argument. If
     the blocked client terminates, its thread does not die until the
     lock request times out. This is a known bug (fixed in MySQL 5.5).

   *  `INET_ATON(EXPR)'

     Given the dotted-quad representation of an IPv4 network address as
     a string, returns an integer that represents the numeric value of
     the address in network byte order (big endian). `INET_ATON()'
     returns `NULL' if it does not understand its argument.

          mysql> SELECT INET_ATON('10.0.5.9');
                  -> 167773449

     For this example, the return value is calculated as 10x256^3 +
     0x256^2 + 5x256 + 9.

     `INET_ATON()' may or may not return a non-`NULL' result for
     short-form IP addresses (such as `'127.1'' as a representation of
     `'127.0.0.1''). Because of this, `INET_ATON()'a should not be used
     for such addresses.

     *Note*:

     To store values generated by `INET_ATON()', use an `INT UNSIGNED'
     column rather than *Note `INT': numeric-types, which is signed. If
     you use a signed column, values corresponding to IP addresses for
     which the first octet is greater than 127 cannot be stored
     correctly. See *Note out-of-range-and-overflow::.

   *  `INET_NTOA(EXPR)'

     Given a numeric IPv4 network address in network byte order,
     returns the dotted-quad representation of the address as a binary
     string. `INET_NTOA()' returns `NULL' if it does not understand its
     argument.

          mysql> SELECT INET_NTOA(167773449);
                  -> '10.0.5.9'

   *  `IS_FREE_LOCK(STR)'

     Checks whether the lock named STR is free to use (that is, not
     locked). Returns `1' if the lock is free (no one is using the
     lock), `0' if the lock is in use, and `NULL' if an error occurs
     (such as an incorrect argument).

   *  `IS_USED_LOCK(STR)'

     Checks whether the lock named STR is in use (that is, locked). If
     so, it returns the connection identifier of the client that holds
     the lock. Otherwise, it returns `NULL'.

   *  `MASTER_POS_WAIT(LOG_NAME,LOG_POS[,TIMEOUT])'

     This function is useful for control of master/slave
     synchronization. It blocks until the slave has read and applied
     all updates up to the specified position in the master log. The
     return value is the number of log events the slave had to wait for
     to advance to the specified position. The function returns `NULL'
     if the slave SQL thread is not started, the slave's master
     information is not initialized, the arguments are incorrect, or an
     error occurs.  It returns `-1' if the timeout has been exceeded.
     If the slave SQL thread stops while `MASTER_POS_WAIT()' is waiting,
     the function returns `NULL'. If the slave is past the specified
     position, the function returns immediately.

     If a TIMEOUT value is specified, `MASTER_POS_WAIT()' stops waiting
     when TIMEOUT seconds have elapsed.  TIMEOUT must be greater than
     0; a zero or negative TIMEOUT means no timeout.

   *  `NAME_CONST(NAME,VALUE)'

     Returns the given value. When used to produce a result set column,
     `NAME_CONST()' causes the column to have the given name. The
     arguments should be constants.

          mysql> SELECT NAME_CONST('myname', 14);
          +--------+
          | myname |
          +--------+
          |     14 |
          +--------+

     This function was added in MySQL 5.0.12. It is for internal use
     only. The server uses it when writing statements from stored
     programs that contain references to local program variables, as
     described in *Note stored-programs-logging::, You might see this
     function in the output from *Note `mysqlbinlog': mysqlbinlog.

   *  `RELEASE_LOCK(STR)'

     Releases the lock named by the string STR that was obtained with
     `GET_LOCK()'. Returns `1' if the lock was released, `0' if the
     lock was not established by this thread (in which case the lock is
     not released), and `NULL' if the named lock did not exist. The
     lock does not exist if it was never obtained by a call to
     `GET_LOCK()' or if it has previously been released.

     The *Note `DO': do. statement is convenient to use with
     `RELEASE_LOCK()'. See *Note do::.

   *  `SLEEP(DURATION)'

     Sleeps (pauses) for the number of seconds given by the DURATION
     argument, then returns 0.  If `SLEEP()' is interrupted, it returns
     1. The duration may have a fractional part given in microseconds.
     This function was added in MySQL 5.0.12.

   *  `UUID()'

     Returns a Universal Unique Identifier (UUID) generated according
     to `DCE 1.1: Remote Procedure Call' (Appendix A) CAE (Common
     Applications Environment) Specifications published by The Open
     Group in October 1997 (Document Number C706,
     `http://www.opengroup.org/public/pubs/catalog/c706.htm').

     A UUID is designed as a number that is globally unique in space
     and time. Two calls to `UUID()' are expected to generate two
     different values, even if these calls are performed on two
     separate computers that are not connected to each other.

     A UUID is a 128-bit number represented by a `utf8' string of five
     hexadecimal numbers in `aaaaaaaa-bbbb-cccc-dddd-eeeeeeeeeeee'
     format:

        * The first three numbers are generated from a timestamp.

        * The fourth number preserves temporal uniqueness in case the
          timestamp value loses monotonicity (for example, due to
          daylight saving time).

        * The fifth number is an IEEE 802 node number that provides
          spatial uniqueness. A random number is substituted if the
          latter is not available (for example, because the host
          computer has no Ethernet card, or we do not know how to find
          the hardware address of an interface on your operating
          system). In this case, spatial uniqueness cannot be
          guaranteed. Nevertheless, a collision should have _very_ low
          probability.

          Currently, the MAC address of an interface is taken into
          account only on FreeBSD and Linux. On other operating
          systems, MySQL uses a randomly generated 48-bit number.

          mysql> SELECT UUID();
                  -> '6ccd780c-baba-1026-9564-0040f4311e29'

     *Warning*:

     Although `UUID()' values are intended to be unique, they are not
     necessarily unguessable or unpredictable. If unpredictability is
     required, UUID values should be generated some other way.

     *Note*:

     `UUID()' does not work with statement-based replication.

   *  `VALUES(COL_NAME)'

     In an *Note `INSERT ... ON DUPLICATE KEY UPDATE':
     insert-on-duplicate. statement, you can use the `VALUES(COL_NAME)'
     function in the *Note `UPDATE': update. clause to refer to column
     values from the *Note `INSERT': insert. portion of the statement.
     In other words, `VALUES(COL_NAME)' in the *Note `UPDATE': update.
     clause refers to the value of COL_NAME that would be inserted, had
     no duplicate-key conflict occurred. This function is especially
     useful in multiple-row inserts. The `VALUES()' function is
     meaningful only in the `ON DUPLICATE KEY UPDATE' clause of *Note
     `INSERT': insert. statements and returns `NULL' otherwise. See
     *Note insert-on-duplicate::.

          mysql> INSERT INTO table (a,b,c) VALUES (1,2,3),(4,5,6)
              -> ON DUPLICATE KEY UPDATE c=VALUES(a)+VALUES(b);


File: manual.info,  Node: group-by-functions-and-modifiers,  Next: spatial-extensions,  Prev: miscellaneous-functions,  Up: functions

12.15 Functions and Modifiers for Use with `GROUP BY' Clauses
=============================================================

* Menu:

* group-by-functions::           `GROUP BY' (Aggregate) Functions
* group-by-modifiers::           `GROUP BY' Modifiers
* group-by-hidden-columns::      `GROUP BY' and `HAVING' with Hidden Columns


File: manual.info,  Node: group-by-functions,  Next: group-by-modifiers,  Prev: group-by-functions-and-modifiers,  Up: group-by-functions-and-modifiers

12.15.1 `GROUP BY' (Aggregate) Functions
----------------------------------------

*Aggregate (`GROUP BY') Functions*

Name                          Description
`AVG()'                       Return the average value of the argument
`BIT_AND()'                   Return bitwise and
`BIT_OR()'                    Return bitwise or
`BIT_XOR()'                   Return bitwise xor
`COUNT(DISTINCT)'             Return the count of a number of different
                              values
`COUNT()'                     Return a count of the number of rows
                              returned
`GROUP_CONCAT()'              Return a concatenated string
`MAX()'                       Return the maximum value
`MIN()'                       Return the minimum value
`STD()'                       Return the population standard deviation
`STDDEV_POP()'                Return the population standard deviation
`STDDEV_SAMP()'               Return the sample standard deviation
`STDDEV()'                    Return the population standard deviation
`SUM()'                       Return the sum
`VAR_POP()'                   Return the population standard variance
`VAR_SAMP()'                  Return the sample variance
`VARIANCE()'                  Return the population standard variance

This section describes group (aggregate) functions that operate on sets
of values. Unless otherwise stated, group functions ignore `NULL'
values.

If you use a group function in a statement containing no `GROUP BY'
clause, it is equivalent to grouping on all rows. For more information,
see *Note group-by-hidden-columns::.

For numeric arguments, the variance and standard deviation functions
return a *Note `DOUBLE': numeric-types. value.  The `SUM()' and `AVG()'
functions return a *Note `DECIMAL': numeric-types. value for exact-value
arguments (integer or *Note `DECIMAL': numeric-types.), and a *Note
`DOUBLE': numeric-types. value for approximate-value arguments (*Note
`FLOAT': numeric-types. or *Note `DOUBLE': numeric-types.). (Before
MySQL 5.0.3, `SUM()' and `AVG()' return *Note `DOUBLE': numeric-types.
for all numeric arguments.)

The `SUM()' and `AVG()' aggregate functions do not work with temporal
values. (They convert the values to numbers, losing everything after
the first nonnumeric character.) To work around this problem, you can
convert to numeric units, perform the aggregate operation, and convert
back to a temporal value.  Examples:

     SELECT SEC_TO_TIME(SUM(TIME_TO_SEC(TIME_COL))) FROM TBL_NAME;
     SELECT FROM_DAYS(SUM(TO_DAYS(DATE_COL))) FROM TBL_NAME;

Functions such as `SUM()' or `AVG()' that expect a numeric argument
cast the argument to a number if necessary. For *Note `SET': set. or
*Note `ENUM': enum. values, the cast operation causes the underlying
numeric value to be used.

   *  `AVG([DISTINCT] EXPR)'

     Returns the average value of `EXPR'. The `DISTINCT' option can be
     used as of MySQL 5.0.3 to return the average of the distinct
     values of EXPR.

     `AVG()' returns `NULL' if there were no matching rows.

          mysql> SELECT student_name, AVG(test_score)
              ->        FROM student
              ->        GROUP BY student_name;

   *  `BIT_AND(EXPR)'

     Returns the bitwise `AND' of all bits in EXPR. The calculation is
     performed with 64-bit (*Note `BIGINT': numeric-types.) precision.

     This function returns `18446744073709551615' if there were no
     matching rows. (This is the value of an unsigned *Note `BIGINT':
     numeric-types. value with all bits set to 1.)

   *  `BIT_OR(EXPR)'

     Returns the bitwise `OR' of all bits in EXPR. The calculation is
     performed with 64-bit (*Note `BIGINT': numeric-types.) precision.

     This function returns `0' if there were no matching rows.

   *  `BIT_XOR(EXPR)'

     Returns the bitwise `XOR' of all bits in EXPR. The calculation is
     performed with 64-bit (*Note `BIGINT': numeric-types.) precision.

     This function returns `0' if there were no matching rows.

   *  `COUNT(EXPR)'

     Returns a count of the number of non-`NULL' values of EXPR in the
     rows retrieved by a *Note `SELECT': select.  statement. The result
     is a *Note `BIGINT': numeric-types. value.

     `COUNT()' returns `0' if there were no matching rows.

          mysql> SELECT student.student_name,COUNT(*)
              ->        FROM student,course
              ->        WHERE student.student_id=course.student_id
              ->        GROUP BY student_name;

     `COUNT(*)' is somewhat different in that it returns a count of the
     number of rows retrieved, whether or not they contain `NULL'
     values.

     `COUNT(*)' is optimized to return very quickly if the *Note
     `SELECT': select. retrieves from one table, no other columns are
     retrieved, and there is no `WHERE' clause. For example:

          mysql> SELECT COUNT(*) FROM student;

     This optimization applies only to `MyISAM' tables only, because an
     exact row count is stored for this storage engine and can be
     accessed very quickly. For transactional storage engines such as
     `InnoDB' and `BDB', storing an exact row count is more problematic
     because multiple transactions may be occurring, each of which may
     affect the count.

   *  `COUNT(DISTINCT EXPR,[EXPR...])'

     Returns a count of the number of rows with different non-`NULL'
     EXPR values.

     `COUNT(DISTINCT)' returns `0' if there were no matching rows.

          mysql> SELECT COUNT(DISTINCT results) FROM student;

     In MySQL, you can obtain the number of distinct expression
     combinations that do not contain `NULL' by giving a list of
     expressions. In standard SQL, you would have to do a concatenation
     of all expressions inside `COUNT(DISTINCT ...)'.

   *  `GROUP_CONCAT(EXPR)'

     This function returns a string result with the concatenated
     non-`NULL' values from a group. It returns `NULL' if there are no
     non-`NULL' values. The full syntax is as follows:

          GROUP_CONCAT([DISTINCT] EXPR [,EXPR ...]
                       [ORDER BY {UNSIGNED_INTEGER | COL_NAME | EXPR}
                           [ASC | DESC] [,COL_NAME ...]]
                       [SEPARATOR STR_VAL])

          mysql> SELECT student_name,
              ->     GROUP_CONCAT(test_score)
              ->     FROM student
              ->     GROUP BY student_name;

     Or:

          mysql> SELECT student_name,
              ->     GROUP_CONCAT(DISTINCT test_score
              ->               ORDER BY test_score DESC SEPARATOR ' ')
              ->     FROM student
              ->     GROUP BY student_name;

     In MySQL, you can get the concatenated values of expression
     combinations. To eliminate duplicate values, use the `DISTINCT'
     clause. To sort values in the result, use the `ORDER BY' clause.
     To sort in reverse order, add the `DESC' (descending) keyword to
     the name of the column you are sorting by in the `ORDER BY'
     clause. The default is ascending order; this may be specified
     explicitly using the `ASC' keyword. The default separator between
     values in a group is comma (``,''). To specify a separator
     explicitly, use `SEPARATOR' followed by the string value that
     should be inserted between group values. To eliminate the
     separator altogether, specify `SEPARATOR '''.

     The result is truncated to the maximum length that is given by the
     `group_concat_max_len' system variable, which has a default value
     of 1024. The value can be set higher, although the effective
     maximum length of the return value is constrained by the value of
     `max_allowed_packet'. The syntax to change the value of
     `group_concat_max_len' at runtime is as follows, where VAL is an
     unsigned integer:

          SET [GLOBAL | SESSION] group_concat_max_len = VAL;

     The return value is a nonbinary or binary string, depending on
     whether the arguments are nonbinary or binary strings.  The result
     type is *Note `TEXT': blob. or *Note `BLOB': blob. unless
     `group_concat_max_len' is less than or equal to 512, in which case
     the result type is *Note `VARCHAR': char. or *Note `VARBINARY':
     binary-varbinary. (Prior to MySQL 5.0.19, `GROUP_CONCAT()'
     returned *Note `TEXT': blob. or *Note `BLOB': blob.
     `group_concat_max_len' greater than 512 only if the query included
     an `ORDER BY' clause.)

     See also `CONCAT()' and `CONCAT_WS()': *Note string-functions::.

   *  `MAX([DISTINCT] EXPR)'

     Returns the maximum value of EXPR.  `MAX()' may take a string
     argument; in such cases, it returns the maximum string value. See
     *Note mysql-indexes::. The `DISTINCT' keyword can be used to find
     the maximum of the distinct values of EXPR, however, this produces
     the same result as omitting `DISTINCT'.

     `MAX()' returns `NULL' if there were no matching rows.

          mysql> SELECT student_name, MIN(test_score), MAX(test_score)
              ->        FROM student
              ->        GROUP BY student_name;

     For `MAX()', MySQL currently compares *Note `ENUM': enum. and
     *Note `SET': set. columns by their string value rather than by the
     string's relative position in the set. This differs from how
     `ORDER BY' compares them. This is expected to be rectified in a
     future MySQL release.

   *  `MIN([DISTINCT] EXPR)'

     Returns the minimum value of EXPR.  `MIN()' may take a string
     argument; in such cases, it returns the minimum string value. See
     *Note mysql-indexes::. The `DISTINCT' keyword can be used to find
     the minimum of the distinct values of EXPR, however, this produces
     the same result as omitting `DISTINCT'.

     `MIN()' returns `NULL' if there were no matching rows.

          mysql> SELECT student_name, MIN(test_score), MAX(test_score)
              ->        FROM student
              ->        GROUP BY student_name;

     For `MIN()', MySQL currently compares *Note `ENUM': enum. and
     *Note `SET': set. columns by their string value rather than by the
     string's relative position in the set. This differs from how
     `ORDER BY' compares them. This is expected to be rectified in a
     future MySQL release.

   *  `STD(EXPR)'

     Returns the population standard deviation of EXPR. This is an
     extension to standard SQL. As of MySQL 5.0.3, the standard SQL
     function `STDDEV_POP()' can be used instead.

     This function returns `NULL' if there were no matching rows.

   *  `STDDEV(EXPR)'

     Returns the population standard deviation of EXPR. This function
     is provided for compatibility with Oracle. As of MySQL 5.0.3, the
     standard SQL function `STDDEV_POP()' can be used instead.

     This function returns `NULL' if there were no matching rows.

   *  `STDDEV_POP(EXPR)'

     Returns the population standard deviation of EXPR (the square root
     of `VAR_POP()'). This function was added in MySQL 5.0.3. Before
     5.0.3, you can use `STD()' or `STDDEV()', which are equivalent but
     not standard SQL.

     `STDDEV_POP()' returns `NULL' if there were no matching rows.

   *  `STDDEV_SAMP(EXPR)'

     Returns the sample standard deviation of EXPR (the square root of
     `VAR_SAMP()'. This function was added in MySQL 5.0.3.

     `STDDEV_SAMP()' returns `NULL' if there were no matching rows.

   *  `SUM([DISTINCT] EXPR)'

     Returns the sum of EXPR. If the return set has no rows, `SUM()'
     returns `NULL'. The `DISTINCT' keyword can be used to sum only the
     distinct values of EXPR.

     `SUM()' returns `NULL' if there were no matching rows.

   *  `VAR_POP(EXPR)'

     Returns the population standard variance of EXPR. It considers
     rows as the whole population, not as a sample, so it has the
     number of rows as the denominator. This function was added in MySQL
     5.0.3. Before 5.0.3, you can use `VARIANCE()', which is equivalent
     but is not standard SQL.

     `VAR_POP()' returns `NULL' if there were no matching rows.

   *  `VAR_SAMP(EXPR)'

     Returns the sample variance of EXPR. That is, the denominator is
     the number of rows minus one. This function was added in MySQL
     5.0.3.

     `VAR_SAMP()' returns `NULL' if there were no matching rows.

   *  `VARIANCE(EXPR)'

     Returns the population standard variance of EXPR. This is an
     extension to standard SQL. As of MySQL 5.0.3, the standard SQL
     function `VAR_POP()' can be used instead.

     `VARIANCE()' returns `NULL' if there were no matching rows.


File: manual.info,  Node: group-by-modifiers,  Next: group-by-hidden-columns,  Prev: group-by-functions,  Up: group-by-functions-and-modifiers

12.15.2 `GROUP BY' Modifiers
----------------------------

The `GROUP BY' clause permits a `WITH ROLLUP' modifier that causes
extra rows to be added to the summary output. These rows represent
higher-level (or super-aggregate) summary operations. `ROLLUP' thus
enables you to answer questions at multiple levels of analysis with a
single query. It can be used, for example, to provide support for OLAP
(Online Analytical Processing) operations.

Suppose that a table named `sales' has `year', `country', `product',
and `profit' columns for recording sales profitability:

     CREATE TABLE sales
     (
         year    INT NOT NULL,
         country VARCHAR(20) NOT NULL,
         product VARCHAR(32) NOT NULL,
         profit  INT
     );

The table's contents can be summarized per year with a simple `GROUP
BY' like this:

     mysql> SELECT year, SUM(profit) FROM sales GROUP BY year;
     +------+-------------+
     | year | SUM(profit) |
     +------+-------------+
     | 2000 |        4525 |
     | 2001 |        3010 |
     +------+-------------+

This output shows the total profit for each year, but if you also want
to determine the total profit summed over all years, you must add up
the individual values yourself or run an additional query.

Or you can use `ROLLUP', which provides both levels of analysis with a
single query. Adding a `WITH ROLLUP' modifier to the `GROUP BY' clause
causes the query to produce another row that shows the grand total over
all year values:

     mysql> SELECT year, SUM(profit) FROM sales GROUP BY year WITH ROLLUP;
     +------+-------------+
     | year | SUM(profit) |
     +------+-------------+
     | 2000 |        4525 |
     | 2001 |        3010 |
     | NULL |        7535 |
     +------+-------------+

The grand total super-aggregate line is identified by the value `NULL'
in the `year' column.

`ROLLUP' has a more complex effect when there are multiple `GROUP BY'
columns. In this case, each time there is a `break' (change in value) in
any but the last grouping column, the query produces an extra
super-aggregate summary row.

For example, without `ROLLUP', a summary on the `sales' table based on
`year', `country', and `product' might look like this:

     mysql> SELECT year, country, product, SUM(profit)
         -> FROM sales
         -> GROUP BY year, country, product;
     +------+---------+------------+-------------+
     | year | country | product    | SUM(profit) |
     +------+---------+------------+-------------+
     | 2000 | Finland | Computer   |        1500 |
     | 2000 | Finland | Phone      |         100 |
     | 2000 | India   | Calculator |         150 |
     | 2000 | India   | Computer   |        1200 |
     | 2000 | USA     | Calculator |          75 |
     | 2000 | USA     | Computer   |        1500 |
     | 2001 | Finland | Phone      |          10 |
     | 2001 | USA     | Calculator |          50 |
     | 2001 | USA     | Computer   |        2700 |
     | 2001 | USA     | TV         |         250 |
     +------+---------+------------+-------------+

The output indicates summary values only at the year/country/product
level of analysis. When `ROLLUP' is added, the query produces several
extra rows:

     mysql> SELECT year, country, product, SUM(profit)
         -> FROM sales
         -> GROUP BY year, country, product WITH ROLLUP;
     +------+---------+------------+-------------+
     | year | country | product    | SUM(profit) |
     +------+---------+------------+-------------+
     | 2000 | Finland | Computer   |        1500 |
     | 2000 | Finland | Phone      |         100 |
     | 2000 | Finland | NULL       |        1600 |
     | 2000 | India   | Calculator |         150 |
     | 2000 | India   | Computer   |        1200 |
     | 2000 | India   | NULL       |        1350 |
     | 2000 | USA     | Calculator |          75 |
     | 2000 | USA     | Computer   |        1500 |
     | 2000 | USA     | NULL       |        1575 |
     | 2000 | NULL    | NULL       |        4525 |
     | 2001 | Finland | Phone      |          10 |
     | 2001 | Finland | NULL       |          10 |
     | 2001 | USA     | Calculator |          50 |
     | 2001 | USA     | Computer   |        2700 |
     | 2001 | USA     | TV         |         250 |
     | 2001 | USA     | NULL       |        3000 |
     | 2001 | NULL    | NULL       |        3010 |
     | NULL | NULL    | NULL       |        7535 |
     +------+---------+------------+-------------+

For this query, adding `ROLLUP' causes the output to include summary
information at four levels of analysis, not just one. Here is how to
interpret the `ROLLUP' output:

   * Following each set of product rows for a given year and country,
     an extra summary row is produced showing the total for all
     products. These rows have the `product' column set to `NULL'.

   * Following each set of rows for a given year, an extra summary row
     is produced showing the total for all countries and products.
     These rows have the `country' and `products' columns set to `NULL'.

   * Finally, following all other rows, an extra summary row is
     produced showing the grand total for all years, countries, and
     products. This row has the `year', `country', and `products'
     columns set to `NULL'.

*Other Considerations When using `ROLLUP'*

The following items list some behaviors specific to the MySQL
implementation of `ROLLUP':

When you use `ROLLUP', you cannot also use an `ORDER BY' clause to sort
the results. In other words, `ROLLUP' and `ORDER BY' are mutually
exclusive. However, you still have some control over sort order. `GROUP
BY' in MySQL sorts results, and you can use explicit `ASC' and `DESC'
keywords with columns named in the `GROUP BY' list to specify sort
order for individual columns. (The higher-level summary rows added by
`ROLLUP' still appear after the rows from which they are calculated,
regardless of the sort order.)

`LIMIT' can be used to restrict the number of rows returned to the
client. `LIMIT' is applied after `ROLLUP', so the limit applies against
the extra rows added by `ROLLUP'. For example:

     mysql> SELECT year, country, product, SUM(profit)
         -> FROM sales
         -> GROUP BY year, country, product WITH ROLLUP
         -> LIMIT 5;
     +------+---------+------------+-------------+
     | year | country | product    | SUM(profit) |
     +------+---------+------------+-------------+
     | 2000 | Finland | Computer   |        1500 |
     | 2000 | Finland | Phone      |         100 |
     | 2000 | Finland | NULL       |        1600 |
     | 2000 | India   | Calculator |         150 |
     | 2000 | India   | Computer   |        1200 |
     +------+---------+------------+-------------+

Using `LIMIT' with `ROLLUP' may produce results that are more difficult
to interpret, because you have less context for understanding the
super-aggregate rows.

The `NULL' indicators in each super-aggregate row are produced when the
row is sent to the client. The server looks at the columns named in the
`GROUP BY' clause following the leftmost one that has changed value. For
any column in the result set with a name that is a lexical match to any
of those names, its value is set to `NULL'. (If you specify grouping
columns by column number, the server identifies which columns to set to
`NULL' by number.)

Because the `NULL' values in the super-aggregate rows are placed into
the result set at such a late stage in query processing, you cannot
test them as `NULL' values within the query itself. For example, you
cannot add `HAVING product IS NULL' to the query to eliminate from the
output all but the super-aggregate rows.

On the other hand, the `NULL' values do appear as `NULL' on the client
side and can be tested as such using any MySQL client programming
interface.


File: manual.info,  Node: group-by-hidden-columns,  Prev: group-by-modifiers,  Up: group-by-functions-and-modifiers

12.15.3 `GROUP BY' and `HAVING' with Hidden Columns
---------------------------------------------------

In standard SQL, a query that includes a `GROUP BY' clause cannot refer
to nonaggregated columns in the select list that are not named in the
`GROUP BY' clause. For example, this query is illegal in standard SQL
because the `name' column in the select list does not appear in the
`GROUP BY':

     SELECT o.custid, c.name, MAX(o.payment)
       FROM orders AS o, customers AS c
       WHERE o.custid = c.custid
       GROUP BY o.custid;

For the query to be legal, the `name' column must be omitted from the
select list or named in the `GROUP BY' clause.

MySQL extends the use of `GROUP BY' so that the select list can refer
to nonaggregated columns not named in the `GROUP BY' clause. This means
that the preceding query is legal in MySQL. You can use this feature to
get better performance by avoiding unnecessary column sorting and
grouping. However, this is useful primarily when all values in each
nonaggregated column not named in the `GROUP BY' are the same for each
group. The server is free to choose any value from each group, so
unless they are the same, the values chosen are indeterminate.
Furthermore, the selection of values from each group cannot be
influenced by adding an `ORDER BY' clause. Sorting of the result set
occurs after values have been chosen, and `ORDER BY' does not affect
which values the server chooses.

A similar MySQL extension applies to the `HAVING' clause. Standard SQL
does not permit the `HAVING' clause to name any column not found in the
`GROUP BY' clause unless it is enclosed in an aggregate function. MySQL
permits the use of such columns to simplify calculations. This
extension assumes that the nongrouped columns will have the same
group-wise values.  Otherwise, the result is indeterminate.

To disable the MySQL `GROUP BY' extension, enable the
`ONLY_FULL_GROUP_BY' SQL mode. This enables standard SQL behavior:
Columns not named in the `GROUP BY' clause cannot be used in the select
list or `HAVING' clause unless enclosed in an aggregate function.

For example, the following query returns `name' values that occur only
once in table `orders':

     SELECT name, COUNT(name) FROM orders
       GROUP BY name
       HAVING COUNT(name) = 1;

However, the result of the following similar query that uses an alias
for the aggregated column depends on the SQL mode:

     SELECT name, COUNT(name) AS c FROM orders
       GROUP BY name
       HAVING c = 1;

In this case, a `non-grouping field 'c' is used in HAVING clause' error
occurs if `ONLY_FULL_GROUP_BY' is enabled because the extension does
not apply. The column `c' in the `HAVING' clause is not enclosed in an
aggregate function (instead, it _is_ an aggregate function).

The select list extension also applies to `ORDER BY'. That is, you can
use nonaggregated columns in the `ORDER BY' clause that do not appear
in the `GROUP BY' clause. (However, as mentioned previously, `ORDER BY'
does not affect which values are chosen from nonaggregated columns; it
only sorts them after they have been chosen.) This extension does not
apply if the `ONLY_FULL_GROUP_BY' SQL mode is enabled.

In some cases, you can use `MIN()' and `MAX()' to obtain a specific
column value even if it is not unique. If the `sort' column contains
integers no larger than 6 digits, the following query gives the value of
`column' from the row containing the smallest `sort' value:

     SUBSTR(MIN(CONCAT(LPAD(sort,6,'0'),column)),7)

See *Note example-maximum-column-group-row::.

If you are trying to follow standard SQL, you cannot use expressions in
`GROUP BY' clauses. As a workaround, use an alias for the expression:

     SELECT id, FLOOR(value/100) AS val
       FROM TBL_NAME
       GROUP BY id, val;

MySQL permits expressions in `GROUP BY' clauses, so the alias is
unnecessary:

     SELECT id, FLOOR(value/100)
       FROM TBL_NAME
       GROUP BY id, FLOOR(value/100);


File: manual.info,  Node: spatial-extensions,  Next: precision-math,  Prev: group-by-functions-and-modifiers,  Up: functions

12.16 Spatial Extensions
========================

* Menu:

* gis-introduction::             Introduction to MySQL Spatial Support
* opengis-geometry-model::       The OpenGIS Geometry Model
* supported-spatial-data-formats::  Supported Spatial Data Formats
* creating-a-spatially-enabled-mysql-database::  Creating a Spatially Enabled MySQL Database
* spatial-analysis-functions::   Spatial Analysis Functions
* optimizing-spatial-analysis::  Optimizing Spatial Analysis
* mysql-gis-conformance-and-compatibility::  MySQL Conformance and Compatibility

MySQL supports spatial extensions to enable the generation, storage,
and analysis of geographic features. Before MySQL 5.0.16, these
features are available for `MyISAM' tables only. As of MySQL 5.0.16,
`InnoDB', *Note `NDB': mysql-cluster, `BDB', and `ARCHIVE' also support
spatial features.

For spatial columns, `MyISAM' supports both `SPATIAL' and non-`SPATIAL'
indexes. Other storage engines support non-`SPATIAL' indexes, as
described in *Note create-index::.

This chapter covers the following topics:

   * The basis of these spatial extensions in the OpenGIS geometry model

   * Data formats for representing spatial data

   * How to use spatial data in MySQL

   * Use of indexing for spatial data

   * MySQL differences from the OpenGIS specification

* Additional Resources *

   * The Open Geospatial Consortium publishes the `OpenGIS(R) Simple
     Features Specifications For SQL', a document that proposes several
     conceptual ways for extending an SQL RDBMS to support spatial
     data. This specification is available from the OGC Web site at
     `http://www.opengis.org/docs/99-049.pdf'.

   * If you have questions or concerns about the use of the spatial
     extensions to MySQL, you can discuss them in the GIS forum:
     `http://forums.mysql.com/list.php?23'.


File: manual.info,  Node: gis-introduction,  Next: opengis-geometry-model,  Prev: spatial-extensions,  Up: spatial-extensions

12.16.1 Introduction to MySQL Spatial Support
---------------------------------------------

MySQL implements spatial extensions following the specification of the
Open Geospatial Consortium (OGC). This is an international consortium
of more than 250 companies, agencies, and universities participating in
the development of publicly available conceptual solutions that can be
useful with all kinds of applications that manage spatial data. The OGC
maintains a Web site at `http://www.opengis.org/'.

In 1997, the Open Geospatial Consortium published the `OpenGIS(R)
Simple Features Specifications For SQL', a document that proposes
several conceptual ways for extending an SQL RDBMS to support spatial
data. This specification is available from the OGC Web site at
`http://www.opengis.org/docs/99-049.pdf'. It contains additional
information relevant to this chapter.

MySQL implements a subset of the *SQL with Geometry Types* environment
proposed by OGC. This term refers to an SQL environment that has been
extended with a set of geometry types. A geometry-valued SQL column is
implemented as a column that has a geometry type. The specification
describe a set of SQL geometry types, as well as functions on those
types to create and analyze geometry values.

A *geographic feature* is anything in the world that has a location. A
feature can be:

   * An entity. For example, a mountain, a pond, a city.

   * A space. For example, town district, the tropics.

   * A definable location. For example, a crossroad, as a particular
     place where two streets intersect.

Some documents use the term *geospatial feature* to refer to geographic
features.

*Geometry* is another word that denotes a geographic feature.
Originally the word *geometry* meant measurement of the earth. Another
meaning comes from cartography, referring to the geometric features
that cartographers use to map the world.

This chapter uses all of these terms synonymously: *geographic feature*,
*geospatial feature*, *feature*, or *geometry*. Here, the term most
commonly used is *geometry*, defined as _a point or an aggregate of
points representing anything in the world that has a location_.


File: manual.info,  Node: opengis-geometry-model,  Next: supported-spatial-data-formats,  Prev: gis-introduction,  Up: spatial-extensions

12.16.2 The OpenGIS Geometry Model
----------------------------------

* Menu:

* gis-geometry-class-hierarchy::  The Geometry Class Hierarchy
* gis-class-geometry::           Class `Geometry'
* gis-class-point::              Class `Point'
* gis-class-curve::              Class `Curve'
* gis-class-linestring::         Class `LineString'
* gis-class-surface::            Class `Surface'
* gis-class-polygon::            Class `Polygon'
* gis-class-geometrycollection::  Class `GeometryCollection'
* gis-class-multipoint::         Class `MultiPoint'
* gis-class-multicurve::         Class `MultiCurve'
* gis-class-multilinestring::    Class `MultiLineString'
* gis-class-multisurface::       Class `MultiSurface'
* gis-class-multipolygon::       Class `MultiPolygon'

The set of geometry types proposed by OGC's *SQL with Geometry Types*
environment is based on the *OpenGIS Geometry Model*. In this model,
each geometric object has the following general properties:

   * It is associated with a Spatial Reference System, which describes
     the coordinate space in which the object is defined.

   * It belongs to some geometry class.


File: manual.info,  Node: gis-geometry-class-hierarchy,  Next: gis-class-geometry,  Prev: opengis-geometry-model,  Up: opengis-geometry-model

12.16.2.1 The Geometry Class Hierarchy
......................................

The geometry classes define a hierarchy as follows:

   * `Geometry' (noninstantiable)

        * `Point' (instantiable)

        * `Curve' (noninstantiable)

             * `LineString' (instantiable)

                  * `Line'

                  * `LinearRing'

        * `Surface' (noninstantiable)

             * `Polygon' (instantiable)

        * `GeometryCollection' (instantiable)

             * `MultiPoint' (instantiable)

             * `MultiCurve' (noninstantiable)

                  * `MultiLineString' (instantiable)

             * `MultiSurface' (noninstantiable)

                  * `MultiPolygon' (instantiable)

It is not possible to create objects in noninstantiable classes.  It is
possible to create objects in instantiable classes. All classes have
properties, and instantiable classes may also have assertions (rules
that define valid class instances).

`Geometry' is the base class. It is an abstract class. The instantiable
subclasses of `Geometry' are restricted to zero-, one-, and
two-dimensional geometric objects that exist in two-dimensional
coordinate space. All instantiable geometry classes are defined so that
valid instances of a geometry class are topologically closed (that is,
all defined geometries include their boundary).

The base `Geometry' class has subclasses for `Point', `Curve',
`Surface', and `GeometryCollection':

   * `Point' represents zero-dimensional objects.

   * `Curve' represents one-dimensional objects, and has subclass
     `LineString', with sub-subclasses `Line' and `LinearRing'.

   * `Surface' is designed for two-dimensional objects and has subclass
     `Polygon'.

   * `GeometryCollection' has specialized zero-, one-, and
     two-dimensional collection classes named `MultiPoint',
     `MultiLineString', and `MultiPolygon' for modeling geometries
     corresponding to collections of `Points', `LineStrings', and
     `Polygons', respectively.  `MultiCurve' and `MultiSurface' are
     introduced as abstract superclasses that generalize the collection
     interfaces to handle `Curves' and `Surfaces'.

`Geometry', `Curve', `Surface', `MultiCurve', and `MultiSurface' are
defined as noninstantiable classes. They define a common set of methods
for their subclasses and are included for extensibility.

`Point', `LineString', `Polygon', `GeometryCollection', `MultiPoint',
`MultiLineString', and `MultiPolygon' are instantiable classes.


File: manual.info,  Node: gis-class-geometry,  Next: gis-class-point,  Prev: gis-geometry-class-hierarchy,  Up: opengis-geometry-model

12.16.2.2 Class `Geometry'
..........................

`Geometry' is the root class of the hierarchy.  It is a noninstantiable
class but has a number of properties that are common to all geometry
values created from any of the `Geometry' subclasses. These properties
are described in the following list. Particular subclasses have their
own specific properties, described later.

*Geometry Properties*

A geometry value has the following properties:

   * Its *type*. Each geometry belongs to one of the instantiable
     classes in the hierarchy.

   * Its *SRID*, or Spatial Reference Identifier. This value identifies
     the geometry's associated Spatial Reference System that describes
     the coordinate space in which the geometry object is defined.

     In MySQL, the SRID value is just an integer associated with the
     geometry value. All calculations are done assuming Euclidean
     (planar) geometry.

   * Its *coordinates* in its Spatial Reference System, represented as
     double-precision (eight-byte) numbers. All nonempty geometries
     include at least one pair of (X,Y) coordinates. Empty geometries
     contain no coordinates.

     Coordinates are related to the SRID. For example, in different
     coordinate systems, the distance between two objects may differ
     even when objects have the same coordinates, because the distance
     on the *planar* coordinate system and the distance on the
     *geocentric* system (coordinates on the Earth's surface) are
     different things.

   * Its *interior*, *boundary*, and *exterior*.

     Every geometry occupies some position in space. The exterior of a
     geometry is all space not occupied by the geometry. The interior
     is the space occupied by the geometry. The boundary is the
     interface between the geometry's interior and exterior.

   * Its *MBR* (Minimum Bounding Rectangle), or Envelope. This is the
     bounding geometry, formed by the minimum and maximum (X,Y)
     coordinates:

          ((MINX MINY, MAXX MINY, MAXX MAXY, MINX MAXY, MINX MINY))

   * Whether the value is *simple* or *nonsimple*. Geometry values of
     types (`LineString', `MultiPoint', `MultiLineString') are either
     simple or nonsimple. Each type determines its own assertions for
     being simple or nonsimple.

   * Whether the value is *closed* or *not closed*. Geometry values of
     types (`LineString', `MultiString') are either closed or not
     closed. Each type determines its own assertions for being closed
     or not closed.

   * Whether the value is *empty* or *nonempty* A geometry is empty if
     it does not have any points. Exterior, interior, and boundary of
     an empty geometry are not defined (that is, they are represented
     by a `NULL' value). An empty geometry is defined to be always
     simple and has an area of 0.

   * Its *dimension*. A geometry can have a dimension of -1, 0, 1, or 2:

        * -1 for an empty geometry.

        * 0 for a geometry with no length and no area.

        * 1 for a geometry with nonzero length and zero area.

        * 2 for a geometry with nonzero area.

     `Point' objects have a dimension of zero.  `LineString' objects
     have a dimension of 1.  `Polygon' objects have a dimension of 2.
     The dimensions of `MultiPoint', `MultiLineString', and
     `MultiPolygon' objects are the same as the dimensions of the
     elements they consist of.


File: manual.info,  Node: gis-class-point,  Next: gis-class-curve,  Prev: gis-class-geometry,  Up: opengis-geometry-model

12.16.2.3 Class `Point'
.......................

A `Point' is a geometry that represents a single location in coordinate
space.

*`Point' Examples*

   * Imagine a large-scale map of the world with many cities. A `Point'
     object could represent each city.

   * On a city map, a `Point' object could represent a bus stop.

*`Point' Properties*

   * X-coordinate value.

   * Y-coordinate value.

   * `Point' is defined as a zero-dimensional geometry.

   * The boundary of a `Point' is the empty set.


File: manual.info,  Node: gis-class-curve,  Next: gis-class-linestring,  Prev: gis-class-point,  Up: opengis-geometry-model

12.16.2.4 Class `Curve'
.......................

A `Curve' is a one-dimensional geometry, usually represented by a
sequence of points. Particular subclasses of `Curve' define the type of
interpolation between points. `Curve' is a noninstantiable class.

*`Curve' Properties*

   * A `Curve' has the coordinates of its points.

   * A `Curve' is defined as a one-dimensional geometry.

   * A `Curve' is simple if it does not pass through the same point
     twice.

   * A `Curve' is closed if its start point is equal to its endpoint.

   * The boundary of a closed `Curve' is empty.

   * The boundary of a nonclosed `Curve' consists of its two endpoints.

   * A `Curve' that is simple and closed is a `LinearRing'.


File: manual.info,  Node: gis-class-linestring,  Next: gis-class-surface,  Prev: gis-class-curve,  Up: opengis-geometry-model

12.16.2.5 Class `LineString'
............................

A `LineString' is a `Curve' with linear interpolation between points.

*`LineString' Examples*

   * On a world map, `LineString' objects could represent rivers.

   * In a city map, `LineString' objects could represent streets.

*`LineString' Properties*

   * A `LineString' has coordinates of segments, defined by each
     consecutive pair of points.

   * A `LineString' is a `Line' if it consists of exactly two points.

   * A `LineString' is a `LinearRing' if it is both closed and simple.


File: manual.info,  Node: gis-class-surface,  Next: gis-class-polygon,  Prev: gis-class-linestring,  Up: opengis-geometry-model

12.16.2.6 Class `Surface'
.........................

A `Surface' is a two-dimensional geometry. It is a noninstantiable
class. Its only instantiable subclass is `Polygon'.

*`Surface' Properties*

   * A `Surface' is defined as a two-dimensional geometry.

   * The OpenGIS specification defines a simple `Surface' as a geometry
     that consists of a single `patch' that is associated with a single
     exterior boundary and zero or more interior boundaries.

   * The boundary of a simple `Surface' is the set of closed curves
     corresponding to its exterior and interior boundaries.


File: manual.info,  Node: gis-class-polygon,  Next: gis-class-geometrycollection,  Prev: gis-class-surface,  Up: opengis-geometry-model

12.16.2.7 Class `Polygon'
.........................

A `Polygon' is a planar `Surface' representing a multisided geometry.
It is defined by a single exterior boundary and zero or more interior
boundaries, where each interior boundary defines a hole in the
`Polygon'.

*`Polygon' Examples*

   * On a region map, `Polygon' objects could represent forests,
     districts, and so on.

*`Polygon' Assertions*

   * The boundary of a `Polygon' consists of a set of `LinearRing'
     objects (that is, `LineString' objects that are both simple and
     closed) that make up its exterior and interior boundaries.

   * A `Polygon' has no rings that cross. The rings in the boundary of
     a `Polygon' may intersect at a `Point', but only as a tangent.

   * A `Polygon' has no lines, spikes, or punctures.

   * A `Polygon' has an interior that is a connected point set.

   * A `Polygon' may have holes. The exterior of a `Polygon' with holes
     is not connected.  Each hole defines a connected component of the
     exterior.

The preceding assertions make a `Polygon' a simple geometry.


File: manual.info,  Node: gis-class-geometrycollection,  Next: gis-class-multipoint,  Prev: gis-class-polygon,  Up: opengis-geometry-model

12.16.2.8 Class `GeometryCollection'
....................................

A `GeometryCollection' is a geometry that is a collection of one or
more geometries of any class.

All the elements in a `GeometryCollection' must be in the same Spatial
Reference System (that is, in the same coordinate system). There are no
other constraints on the elements of a `GeometryCollection', although
the subclasses of `GeometryCollection' described in the following
sections may restrict membership.  Restrictions may be based on:

   * Element type (for example, a `MultiPoint' may contain only `Point'
     elements)

   * Dimension

   * Constraints on the degree of spatial overlap between elements


File: manual.info,  Node: gis-class-multipoint,  Next: gis-class-multicurve,  Prev: gis-class-geometrycollection,  Up: opengis-geometry-model

12.16.2.9 Class `MultiPoint'
............................

A `MultiPoint' is a geometry collection composed of `Point' elements.
The points are not connected or ordered in any way.

*`MultiPoint' Examples*

   * On a world map, a `MultiPoint' could represent a chain of small
     islands.

   * On a city map, a `MultiPoint' could represent the outlets for a
     ticket office.

*`MultiPoint' Properties*

   * A `MultiPoint' is a zero-dimensional geometry.

   * A `MultiPoint' is simple if no two of its `Point' values are equal
     (have identical coordinate values).

   * The boundary of a `MultiPoint' is the empty set.


File: manual.info,  Node: gis-class-multicurve,  Next: gis-class-multilinestring,  Prev: gis-class-multipoint,  Up: opengis-geometry-model

12.16.2.10 Class `MultiCurve'
.............................

A `MultiCurve' is a geometry collection composed of `Curve' elements.
`MultiCurve' is a noninstantiable class.

*`MultiCurve' Properties*

   * A `MultiCurve' is a one-dimensional geometry.

   * A `MultiCurve' is simple if and only if all of its elements are
     simple; the only intersections between any two elements occur at
     points that are on the boundaries of both elements.

   * A `MultiCurve' boundary is obtained by applying the `mod 2 union
     rule' (also known as the `odd-even rule'): A point is in the
     boundary of a `MultiCurve' if it is in the boundaries of an odd
     number of `MultiCurve' elements.

   * A `MultiCurve' is closed if all of its elements are closed.

   * The boundary of a closed `MultiCurve' is always empty.


File: manual.info,  Node: gis-class-multilinestring,  Next: gis-class-multisurface,  Prev: gis-class-multicurve,  Up: opengis-geometry-model

12.16.2.11 Class `MultiLineString'
..................................

A `MultiLineString' is a `MultiCurve' geometry collection composed of
`LineString' elements.

*`MultiLineString' Examples*

   * On a region map, a `MultiLineString' could represent a river
     system or a highway system.


File: manual.info,  Node: gis-class-multisurface,  Next: gis-class-multipolygon,  Prev: gis-class-multilinestring,  Up: opengis-geometry-model

12.16.2.12 Class `MultiSurface'
...............................

A `MultiSurface' is a geometry collection composed of surface elements.
`MultiSurface' is a noninstantiable class. Its only instantiable
subclass is `MultiPolygon'.

*`MultiSurface' Assertions*

   * Two `MultiSurface' surfaces have no interiors that intersect.

   * Two `MultiSurface' elements have boundaries that intersect at most
     at a finite number of points.


File: manual.info,  Node: gis-class-multipolygon,  Prev: gis-class-multisurface,  Up: opengis-geometry-model

12.16.2.13 Class `MultiPolygon'
...............................

A `MultiPolygon' is a `MultiSurface' object composed of `Polygon'
elements.

*`MultiPolygon' Examples*

   * On a region map, a `MultiPolygon' could represent a system of
     lakes.

*`MultiPolygon' Assertions*

   * A `MultiPolygon' has no two `Polygon' elements with interiors that
     intersect.

   * A `MultiPolygon' has no two `Polygon' elements that cross
     (crossing is also forbidden by the previous assertion), or that
     touch at an infinite number of points.

   * A `MultiPolygon' may not have cut lines, spikes, or punctures. A
     `MultiPolygon' is a regular, closed point set.

   * A `MultiPolygon' that has more than one `Polygon' has an interior
     that is not connected. The number of connected components of the
     interior of a `MultiPolygon' is equal to the number of `Polygon'
     values in the `MultiPolygon'.

*`MultiPolygon' Properties*

   * A `MultiPolygon' is a two-dimensional geometry.

   * A `MultiPolygon' boundary is a set of closed curves (`LineString'
     values) corresponding to the boundaries of its `Polygon' elements.

   * Each `Curve' in the boundary of the `MultiPolygon' is in the
     boundary of exactly one `Polygon' element.

   * Every `Curve' in the boundary of an `Polygon' element is in the
     boundary of the `MultiPolygon'.


File: manual.info,  Node: supported-spatial-data-formats,  Next: creating-a-spatially-enabled-mysql-database,  Prev: opengis-geometry-model,  Up: spatial-extensions

12.16.3 Supported Spatial Data Formats
--------------------------------------

* Menu:

* gis-wkt-format::               Well-Known Text (WKT) Format
* gis-wkb-format::               Well-Known Binary (WKB) Format

This section describes the standard spatial data formats that are used
to represent geometry objects in queries. They are:

   * Well-Known Text (WKT) format

   * Well-Known Binary (WKB) format

Internally, MySQL stores geometry values in a format that is not
identical to either WKT or WKB format.


File: manual.info,  Node: gis-wkt-format,  Next: gis-wkb-format,  Prev: supported-spatial-data-formats,  Up: supported-spatial-data-formats

12.16.3.1 Well-Known Text (WKT) Format
......................................

The Well-Known Text (WKT) representation of Geometry is designed to
exchange geometry data in ASCII form. For a Backus-Naur grammar that
specifies the formal production rules for writing WKT values, see the
OpenGIS specification document referenced in *Note spatial-extensions::.

Examples of WKT representations of geometry objects:

   * A `Point':

          POINT(15 20)

     Note that point coordinates are specified with no separating
     comma. This differs from the syntax for the SQL `POINT()'
     function, which requires a comma between the coordinates. Take
     care to use the syntax appropriate to the context of a given
     spatial operation. For example, the following statements both
     extract the X-coordinate from a `Point' object. The first produces
     the object directly using the `POINT()' function. The second uses
     a WKT representation converted to a `Point' with `GeomFromText()'.

          mysql> SELECT X(POINT(15, 20));
          +------------------+
          | X(POINT(15, 20)) |
          +------------------+
          |               15 |
          +------------------+

          mysql> SELECT X(GeomFromText('POINT(15 20)'));
          +---------------------------------+
          | X(GeomFromText('POINT(15 20)')) |
          +---------------------------------+
          |                              15 |
          +---------------------------------+

   * A `LineString' with four points:

          LINESTRING(0 0, 10 10, 20 25, 50 60)

     Note that point coordinate pairs are separated by commas.

   * A `Polygon' with one exterior ring and one interior ring:

          POLYGON((0 0,10 0,10 10,0 10,0 0),(5 5,7 5,7 7,5 7, 5 5))

   * A `MultiPoint' with three `Point' values:

          MULTIPOINT(0 0, 20 20, 60 60)

   * A `MultiLineString' with two `LineString' values:

          MULTILINESTRING((10 10, 20 20), (15 15, 30 15))

   * A `MultiPolygon' with two `Polygon' values:

          MULTIPOLYGON(((0 0,10 0,10 10,0 10,0 0)),((5 5,7 5,7 7,5 7, 5 5)))

   * A `GeometryCollection' consisting of two `Point' values and one
     `LineString':

          GEOMETRYCOLLECTION(POINT(10 10), POINT(30 30), LINESTRING(15 15, 20 20))


File: manual.info,  Node: gis-wkb-format,  Prev: gis-wkt-format,  Up: supported-spatial-data-formats

12.16.3.2 Well-Known Binary (WKB) Format
........................................

The Well-Known Binary (WKB) representation for geometric values is
defined by the OpenGIS specification. It is also defined in the ISO
`SQL/MM Part 3: Spatial' standard.

WKB is used to exchange geometry data as binary streams represented by
*Note `BLOB': blob. values containing geometric WKB information.

WKB uses one-byte unsigned integers, four-byte unsigned integers, and
eight-byte double-precision numbers (IEEE 754 format). A byte is eight
bits.

For example, a WKB value that corresponds to `POINT(1 1)' consists of
this sequence of 21 bytes (each represented here by two hex digits):

     0101000000000000000000F03F000000000000F03F

The sequence may be broken down into these components:

     Byte order : 01
     WKB type   : 01000000
     X          : 000000000000F03F
     Y          : 000000000000F03F

Component representation is as follows:

   * The byte order may be either 1 or 0 to indicate little-endian or
     big-endian storage. The little-endian and big-endian byte orders
     are also known as Network Data Representation (NDR) and External
     Data Representation (XDR), respectively.

   * The WKB type is a code that indicates the geometry type.  Values
     from 1 through 7 indicate `Point', `LineString', `Polygon',
     `MultiPoint', `MultiLineString', `MultiPolygon', and
     `GeometryCollection'.

   * A `Point' value has X and Y coordinates, each represented as a
     double-precision value.

WKB values for more complex geometry values are represented by more
complex data structures, as detailed in the OpenGIS specification.


File: manual.info,  Node: creating-a-spatially-enabled-mysql-database,  Next: spatial-analysis-functions,  Prev: supported-spatial-data-formats,  Up: spatial-extensions

12.16.4 Creating a Spatially Enabled MySQL Database
---------------------------------------------------

* Menu:

* mysql-spatial-datatypes::      MySQL Spatial Data Types
* creating-spatial-values::      Creating Spatial Values
* creating-spatial-columns::     Creating Spatial Columns
* populating-spatial-columns::   Populating Spatial Columns
* fetching-spatial-data::        Fetching Spatial Data

This section describes the data types you can use for representing
spatial data in MySQL, and the functions available for creating and
retrieving spatial values.


File: manual.info,  Node: mysql-spatial-datatypes,  Next: creating-spatial-values,  Prev: creating-a-spatially-enabled-mysql-database,  Up: creating-a-spatially-enabled-mysql-database

12.16.4.1 MySQL Spatial Data Types
..................................

MySQL has data types that correspond to OpenGIS classes. Some of these
types hold single geometry values:

   * `GEOMETRY'

   * `POINT'

   * `LINESTRING'

   * `POLYGON'

`GEOMETRY' can store geometry values of any type. The other
single-value types (`POINT', `LINESTRING', and `POLYGON') restrict
their values to a particular geometry type.

The other data types hold collections of values:

   * `MULTIPOINT'

   * `MULTILINESTRING'

   * `MULTIPOLYGON'

   * `GEOMETRYCOLLECTION'

`GEOMETRYCOLLECTION' can store a collection of objects of any type. The
other collection types (`MULTIPOINT', `MULTILINESTRING',
`MULTIPOLYGON', and `GEOMETRYCOLLECTION') restrict collection members
to those having a particular geometry type.


File: manual.info,  Node: creating-spatial-values,  Next: creating-spatial-columns,  Prev: mysql-spatial-datatypes,  Up: creating-a-spatially-enabled-mysql-database

12.16.4.2 Creating Spatial Values
.................................

* Menu:

* gis-wkt-functions::            Creating Geometry Values Using WKT Functions
* gis-wkb-functions::            Creating Geometry Values Using WKB Functions
* gis-mysql-specific-functions::  Creating Geometry Values Using MySQL-Specific Functions

This section describes how to create spatial values using Well-Known
Text and Well-Known Binary functions that are defined in the OpenGIS
standard, and using MySQL-specific functions.


File: manual.info,  Node: gis-wkt-functions,  Next: gis-wkb-functions,  Prev: creating-spatial-values,  Up: creating-spatial-values

12.16.4.3 Creating Geometry Values Using WKT Functions
......................................................

MySQL provides a number of functions that take as arguments a
Well-Known Text representation and, optionally, a spatial reference
system identifier (SRID). They return the corresponding geometry.

`GeomFromText()' accepts a WKT of any geometry type as its first
argument. An implementation also provides type-specific construction
functions for construction of geometry values of each geometry type.

   *  `GeomCollFromText(WKT[,SRID])',
     `GeometryCollectionFromText(WKT[,SRID])'

     Constructs a `GEOMETRYCOLLECTION' value using its WKT
     representation and SRID.

   *  `GeomFromText(WKT[,SRID])', `GeometryFromText(WKT[,SRID])'

     Constructs a geometry value of any type using its WKT
     representation and SRID.

   *  `LineFromText(WKT[,SRID])', `LineStringFromText(WKT[,SRID])'

     Constructs a `LINESTRING' value using its WKT representation and
     SRID.

   *  `MLineFromText(WKT[,SRID])', `MultiLineStringFromText(WKT[,SRID])'

     Constructs a `MULTILINESTRING' value using its WKT representation
     and SRID.

   *  `MPointFromText(WKT[,SRID])', `MultiPointFromText(WKT[,SRID])'

     Constructs a `MULTIPOINT' value using its WKT representation and
     SRID.

   *  `MPolyFromText(WKT[,SRID])', `MultiPolygonFromText(WKT[,SRID])'

     Constructs a `MULTIPOLYGON' value using its WKT representation and
     SRID.

   *  `PointFromText(WKT[,SRID])'

     Constructs a `POINT' value using its WKT representation and SRID.

   *  `PolyFromText(WKT[,SRID])', `PolygonFromText(WKT[,SRID])'

     Constructs a `POLYGON' value using its WKT representation and SRID.

The OpenGIS specification also defines the following optional
functions, which MySQL does not implement. These functions construct
`Polygon' or `MultiPolygon' values based on the WKT representation of a
collection of rings or closed `LineString' values. These values may
intersect.

   *  `BdMPolyFromText(WKT,SRID)'

     Constructs a `MultiPolygon' value from a `MultiLineString' value
     in WKT format containing an arbitrary collection of closed
     `LineString' values.

   *  `BdPolyFromText(WKT,SRID)'

     Constructs a `Polygon' value from a `MultiLineString' value in WKT
     format containing an arbitrary collection of closed `LineString'
     values.


File: manual.info,  Node: gis-wkb-functions,  Next: gis-mysql-specific-functions,  Prev: gis-wkt-functions,  Up: creating-spatial-values

12.16.4.4 Creating Geometry Values Using WKB Functions
......................................................

MySQL provides a number of functions that take as arguments a *Note
`BLOB': blob. containing a Well-Known Binary representation and,
optionally, a spatial reference system identifier (SRID). They return
the corresponding geometry.

As of MySQL 5.0.82, these functions also accept geometry objects for
compatibility with the changes made in MySQL 5.0.82 to the return value
of the functions in *Note gis-mysql-specific-functions::. Thus, those
functions may continue to be used to provide the first argument to the
functions in this section.

   *  `GeomCollFromWKB(WKB[,SRID])',
     `GeometryCollectionFromWKB(WKB[,SRID])'

     Constructs a `GEOMETRYCOLLECTION' value using its WKB
     representation and SRID.

   *  `GeomFromWKB(WKB[,SRID])', `GeometryFromWKB(WKB[,SRID])'

     Constructs a geometry value of any type using its WKB
     representation and SRID.

   *  `LineFromWKB(WKB[,SRID])', `LineStringFromWKB(WKB[,SRID])'

     Constructs a `LINESTRING' value using its WKB representation and
     SRID.

   *  `MLineFromWKB(WKB[,SRID])', `MultiLineStringFromWKB(WKB[,SRID])'

     Constructs a `MULTILINESTRING' value using its WKB representation
     and SRID.

   *  `MPointFromWKB(WKB[,SRID])', `MultiPointFromWKB(WKB[,SRID])'

     Constructs a `MULTIPOINT' value using its WKB representation and
     SRID.

   *  `MPolyFromWKB(WKB[,SRID])', `MultiPolygonFromWKB(WKB[,SRID])'

     Constructs a `MULTIPOLYGON' value using its WKB representation and
     SRID.

   *  `PointFromWKB(WKB[,SRID])'

     Constructs a `POINT' value using its WKB representation and SRID.

   *  `PolyFromWKB(WKB[,SRID])', `PolygonFromWKB(WKB[,SRID])'

     Constructs a `POLYGON' value using its WKB representation and SRID.

The OpenGIS specification also describes optional functions for
constructing `Polygon' or `MultiPolygon' values based on the WKB
representation of a collection of rings or closed `LineString' values.
These values may intersect. MySQL does not implement these functions:

   *  `BdMPolyFromWKB(WKB,SRID)'

     Constructs a `MultiPolygon' value from a `MultiLineString' value
     in WKB format containing an arbitrary collection of closed
     `LineString' values.

   *  `BdPolyFromWKB(WKB,SRID)'

     Constructs a `Polygon' value from a `MultiLineString' value in WKB
     format containing an arbitrary collection of closed `LineString'
     values.


File: manual.info,  Node: gis-mysql-specific-functions,  Prev: gis-wkb-functions,  Up: creating-spatial-values

12.16.4.5 Creating Geometry Values Using MySQL-Specific Functions
.................................................................

MySQL provides a set of useful nonstandard functions for creating
geometry values. The functions described in this section are MySQL
extensions to the OpenGIS specification.

As of MySQL 5.0.82, these functions produce geometry objects from
either WKB values or geometry objects as arguments. If any argument is
not a proper WKB or geometry representation of the proper object type,
the return value is `NULL'.

Before MySQL 5.0.82, these functions produce *Note `BLOB': blob. values
containing WKB representations of geometry values with no SRID from WKB
arguments. The WKB value returned from these functions can be converted
to geometry arguments by using them as the first argument to functions
in the `GeomFromWKB()' function family.

For example, as of MySQL 5.0.82, you can insert the geometry return
value from `Point()' directly into a `Point' column:

     INSERT INTO t1 (pt_col) VALUES(Point(1,2));

Prior to MySQL 5.0.82, convert the WKB return value to a `Point' before
inserting it:

     INSERT INTO t1 (pt_col) VALUES(GeomFromWKB(Point(1,2)));

   *  `GeometryCollection(G1,G2,...)'

     Constructs a `GeometryCollection'.

   *  `LineString(PT1,PT2,...)'

     Constructs a `LineString' value from a number of `Point' or WKB
     `Point' arguments. If the number of arguments is less than two,
     the return value is `NULL'.

   *  `MultiLineString(LS1,LS2,...)'

     Constructs a `MultiLineString' value using `LineString' or WKB
     `LineString' arguments.

   *  `MultiPoint(PT1,PT2,...)'

     Constructs a `MultiPoint' value using `Point' or WKB `Point'
     arguments.

   *  `MultiPolygon(POLY1,POLY2,...)'

     Constructs a `MultiPolygon' value from a set of `Polygon' or WKB
     `Polygon' arguments.

   *  `Point(X,Y)'

     Constructs a `Point' using its coordinates.

   *  `Polygon(LS1,LS2,...)'

     Constructs a `Polygon' value from a number of `LineString' or WKB
     `LineString' arguments. If any argument does not represent a
     `LinearRing' (that is, not a closed and simple `LineString'), the
     return value is `NULL'.


File: manual.info,  Node: creating-spatial-columns,  Next: populating-spatial-columns,  Prev: creating-spatial-values,  Up: creating-a-spatially-enabled-mysql-database

12.16.4.6 Creating Spatial Columns
..................................

MySQL provides a standard way of creating spatial columns for geometry
types, for example, with *Note `CREATE TABLE': create-table. or *Note
`ALTER TABLE': alter-table.  Currently, spatial columns are supported
for `MyISAM', `InnoDB', *Note `NDB': mysql-cluster, `BDB', and
`ARCHIVE' tables. (Support for storage engines other than `MyISAM' was
added in MySQL 5.0.16.)  See also the annotations about spatial indexes
under *Note creating-spatial-indexes::.

   * Use the *Note `CREATE TABLE': create-table.  statement to create a
     table with a spatial column:

          CREATE TABLE geom (g GEOMETRY);

   * Use the *Note `ALTER TABLE': alter-table. statement to add or drop
     a spatial column to or from an existing table:

          ALTER TABLE geom ADD pt POINT;
          ALTER TABLE geom DROP pt;


File: manual.info,  Node: populating-spatial-columns,  Next: fetching-spatial-data,  Prev: creating-spatial-columns,  Up: creating-a-spatially-enabled-mysql-database

12.16.4.7 Populating Spatial Columns
....................................

After you have created spatial columns, you can populate them with
spatial data.

Values should be stored in internal geometry format, but you can
convert them to that format from either Well-Known Text (WKT) or
Well-Known Binary (WKB) format. The following examples demonstrate how
to insert geometry values into a table by converting WKT values into
internal geometry format:

   * Perform the conversion directly in the *Note `INSERT': insert.
     statement:

          INSERT INTO geom VALUES (GeomFromText('POINT(1 1)'));

          SET @g = 'POINT(1 1)';
          INSERT INTO geom VALUES (GeomFromText(@g));

   * Perform the conversion prior to the *Note `INSERT': insert.:

          SET @g = GeomFromText('POINT(1 1)');
          INSERT INTO geom VALUES (@g);

The following examples insert more complex geometries into the table:

     SET @g = 'LINESTRING(0 0,1 1,2 2)';
     INSERT INTO geom VALUES (GeomFromText(@g));

     SET @g = 'POLYGON((0 0,10 0,10 10,0 10,0 0),(5 5,7 5,7 7,5 7, 5 5))';
     INSERT INTO geom VALUES (GeomFromText(@g));

     SET @g =
     'GEOMETRYCOLLECTION(POINT(1 1),LINESTRING(0 0,1 1,2 2,3 3,4 4))';
     INSERT INTO geom VALUES (GeomFromText(@g));

The preceding examples all use `GeomFromText()' to create geometry
values. You can also use type-specific functions:

     SET @g = 'POINT(1 1)';
     INSERT INTO geom VALUES (PointFromText(@g));

     SET @g = 'LINESTRING(0 0,1 1,2 2)';
     INSERT INTO geom VALUES (LineStringFromText(@g));

     SET @g = 'POLYGON((0 0,10 0,10 10,0 10,0 0),(5 5,7 5,7 7,5 7, 5 5))';
     INSERT INTO geom VALUES (PolygonFromText(@g));

     SET @g =
     'GEOMETRYCOLLECTION(POINT(1 1),LINESTRING(0 0,1 1,2 2,3 3,4 4))';
     INSERT INTO geom VALUES (GeomCollFromText(@g));

Note that if a client application program wants to use WKB
representations of geometry values, it is responsible for sending
correctly formed WKB in queries to the server. However, there are
several ways of satisfying this requirement. For example:

   * Inserting a `POINT(1 1)' value with hex literal syntax:

          mysql> INSERT INTO geom VALUES
              -> (GeomFromWKB(0x0101000000000000000000F03F000000000000F03F));

   * An ODBC application can send a WKB representation, binding it to a
     placeholder using an argument of *Note `BLOB': blob. type:

          INSERT INTO geom VALUES (GeomFromWKB(?))

     Other programming interfaces may support a similar placeholder
     mechanism.

   * In a C program, you can escape a binary value using *Note
     `mysql_real_escape_string()': mysql-real-escape-string.  and
     include the result in a query string that is sent to the server.
     See *Note mysql-real-escape-string::.


File: manual.info,  Node: fetching-spatial-data,  Prev: populating-spatial-columns,  Up: creating-a-spatially-enabled-mysql-database

12.16.4.8 Fetching Spatial Data
...............................

Geometry values stored in a table can be fetched in internal format.
You can also convert them into WKT or WKB format.

   * Fetching spatial data in internal format:

     Fetching geometry values using internal format can be useful in
     table-to-table transfers:

          CREATE TABLE geom2 (g GEOMETRY) SELECT g FROM geom;

   * Fetching spatial data in WKT format:

     The `AsText()' function converts a geometry from internal format
     into a WKT string.

          SELECT AsText(g) FROM geom;

   * Fetching spatial data in WKB format:

     The `AsBinary()' function converts a geometry from internal format
     into a *Note `BLOB': blob. containing the WKB value.

          SELECT AsBinary(g) FROM geom;


File: manual.info,  Node: spatial-analysis-functions,  Next: optimizing-spatial-analysis,  Prev: creating-a-spatially-enabled-mysql-database,  Up: spatial-extensions

12.16.5 Spatial Analysis Functions
----------------------------------

* Menu:

* functions-to-convert-geometries-between-formats::  Geometry Format Conversion Functions
* geometry-property-functions::  `Geometry' Functions
* functions-that-create-new-geometries-from-existing-ones::  Functions That Create New Geometries from Existing Ones
* functions-for-testing-spatial-relations-between-geometric-objects::  Functions for Testing Spatial Relations Between Geometric Objects

After populating spatial columns with values, you are ready to query
and analyze them. MySQL provides a set of functions to perform various
operations on spatial data. These functions can be grouped into four
major categories according to the type of operation they perform:

   * Functions that convert geometries between various formats

   * Functions that provide access to qualitative or quantitative
     properties of a geometry

   * Functions that describe relations between two geometries

   * Functions that create new geometries from existing ones

Spatial analysis functions can be used in many contexts, such as:

   * Any interactive SQL program, such as *Note `mysql': mysql.

   * Application programs written in any language that supports a MySQL
     client API


File: manual.info,  Node: functions-to-convert-geometries-between-formats,  Next: geometry-property-functions,  Prev: spatial-analysis-functions,  Up: spatial-analysis-functions

12.16.5.1 Geometry Format Conversion Functions
..............................................

MySQL supports the following functions for converting geometry values
between internal format and either WKT or WKB format:

   *  `AsBinary(G)', `AsWKB(G)'

     Converts a value in internal geometry format to its WKB
     representation and returns the binary result.

          SELECT AsBinary(g) FROM geom;

   *  `AsText(G)', `AsWKT(G)'

     Converts a value in internal geometry format to its WKT
     representation and returns the string result.

          mysql> SET @g = 'LineString(1 1,2 2,3 3)';
          mysql> SELECT AsText(GeomFromText(@g));
          +--------------------------+
          | AsText(GeomFromText(@g)) |
          +--------------------------+
          | LINESTRING(1 1,2 2,3 3)  |
          +--------------------------+

   * `GeomFromText(WKT[,SRID])'

     Converts a string value from its WKT representation into internal
     geometry format and returns the result. A number of type-specific
     functions are also supported, such as `PointFromText()' and
     `LineFromText()'. See *Note gis-wkt-functions::.

   * `GeomFromWKB(WKB[,SRID])'

     Converts a binary value from its WKB representation into internal
     geometry format and returns the result. A number of type-specific
     functions are also supported, such as `PointFromWKB()' and
     `LineFromWKB()'. See *Note gis-wkb-functions::.


File: manual.info,  Node: geometry-property-functions,  Next: functions-that-create-new-geometries-from-existing-ones,  Prev: functions-to-convert-geometries-between-formats,  Up: spatial-analysis-functions

12.16.5.2 `Geometry' Functions
..............................

* Menu:

* general-geometry-property-functions::  General Geometry Functions
* point-property-functions::     `Point' Functions
* linestring-property-functions::  `LineString' Functions
* multilinestring-property-functions::  `MultiLineString' Functions
* polygon-property-functions::   `Polygon' Functions
* multipolygon-property-functions::  `MultiPolygon' Functions
* geometrycollection-property-functions::  `GeometryCollection' Functions

Each function that belongs to this group takes a geometry value as its
argument and returns some quantitative or qualitative property of the
geometry. Some functions restrict their argument type. Such functions
return `NULL' if the argument is of an incorrect geometry type. For
example, `Area()' returns `NULL' if the object type is neither
`Polygon' nor `MultiPolygon'.


File: manual.info,  Node: general-geometry-property-functions,  Next: point-property-functions,  Prev: geometry-property-functions,  Up: geometry-property-functions

12.16.5.3 General Geometry Functions
....................................

The functions listed in this section do not restrict their argument and
accept a geometry value of any type.

   *  `Dimension(G)'

     Returns the inherent dimension of the geometry value G. The result
     can be -1, 0, 1, or 2. The meaning of these values is given in
     *Note gis-class-geometry::.

          mysql> SELECT Dimension(GeomFromText('LineString(1 1,2 2)'));
          +------------------------------------------------+
          | Dimension(GeomFromText('LineString(1 1,2 2)')) |
          +------------------------------------------------+
          |                                              1 |
          +------------------------------------------------+

   *  `Envelope(G)'

     Returns the Minimum Bounding Rectangle (MBR) for the geometry
     value G. The result is returned as a `Polygon' value.

     The polygon is defined by the corner points of the bounding box:

          POLYGON((MINX MINY, MAXX MINY, MAXX MAXY, MINX MAXY, MINX MINY))

          mysql> SELECT AsText(Envelope(GeomFromText('LineString(1 1,2 2)')));
          +-------------------------------------------------------+
          | AsText(Envelope(GeomFromText('LineString(1 1,2 2)'))) |
          +-------------------------------------------------------+
          | POLYGON((1 1,2 1,2 2,1 2,1 1))                        |
          +-------------------------------------------------------+

   *  `GeometryType(G)'

     Returns as a string the name of the geometry type of which the
     geometry instance G is a member. The name corresponds to one of
     the instantiable `Geometry' subclasses.

          mysql> SELECT GeometryType(GeomFromText('POINT(1 1)'));
          +------------------------------------------+
          | GeometryType(GeomFromText('POINT(1 1)')) |
          +------------------------------------------+
          | POINT                                    |
          +------------------------------------------+

   *  `SRID(G)'

     Returns an integer indicating the Spatial Reference System ID for
     the geometry value G.

     In MySQL, the SRID value is just an integer associated with the
     geometry value. All calculations are done assuming Euclidean
     (planar) geometry.

          mysql> SELECT SRID(GeomFromText('LineString(1 1,2 2)',101));
          +-----------------------------------------------+
          | SRID(GeomFromText('LineString(1 1,2 2)',101)) |
          +-----------------------------------------------+
          |                                           101 |
          +-----------------------------------------------+

The OpenGIS specification also defines the following functions, which
MySQL does not implement:

   *  `Boundary(G)'

     Returns a geometry that is the closure of the combinatorial
     boundary of the geometry value G.

   *  `IsEmpty(G)'

     Returns 1 if the geometry value G is the empty geometry, 0 if it
     is not empty, and -1 if the argument is `NULL'. If the geometry is
     empty, it represents the empty point set.

   *  `IsSimple(G)'

     Currently, this function is a placeholder and should not be used.
     If implemented, its behavior will be as described in the next
     paragraph.

     Returns 1 if the geometry value G has no anomalous geometric
     points, such as self-intersection or self-tangency.  `IsSimple()'
     returns 0 if the argument is not simple, and -1 if it is `NULL'.

     The description of each instantiable geometric class given earlier
     in the chapter includes the specific conditions that cause an
     instance of that class to be classified as not simple. (See *Note
     gis-geometry-class-hierarchy::.)


File: manual.info,  Node: point-property-functions,  Next: linestring-property-functions,  Prev: general-geometry-property-functions,  Up: geometry-property-functions

12.16.5.4 `Point' Functions
...........................

A `Point' consists of X and Y coordinates, which may be obtained using
the following functions:

   *  `X(P)'

     Returns the X-coordinate value for the `Point' object P as a
     double-precision number.

          mysql> SELECT X(POINT(56.7, 53.34));
          +-----------------------+
          | X(POINT(56.7, 53.34)) |
          +-----------------------+
          |                  56.7 |
          +-----------------------+

   *  `Y(P)'

     Returns the Y-coordinate value for the `Point' object P as a
     double-precision number.

          mysql> SELECT Y(POINT(56.7, 53.34));
          +-----------------------+
          | Y(POINT(56.7, 53.34)) |
          +-----------------------+
          |                 53.34 |
          +-----------------------+


File: manual.info,  Node: linestring-property-functions,  Next: multilinestring-property-functions,  Prev: point-property-functions,  Up: geometry-property-functions

12.16.5.5 `LineString' Functions
................................

A `LineString' consists of `Point' values. You can extract particular
points of a `LineString', count the number of points that it contains,
or obtain its length.

   *  `EndPoint(LS)'

     Returns the `Point' that is the endpoint of the `LineString' value
     LS.

          mysql> SET @ls = 'LineString(1 1,2 2,3 3)';
          mysql> SELECT AsText(EndPoint(GeomFromText(@ls)));
          +-------------------------------------+
          | AsText(EndPoint(GeomFromText(@ls))) |
          +-------------------------------------+
          | POINT(3 3)                          |
          +-------------------------------------+

   *  `GLength(LS)'

     Returns as a double-precision number the length of the
     `LineString' value LS in its associated spatial reference.

          mysql> SET @ls = 'LineString(1 1,2 2,3 3)';
          mysql> SELECT GLength(GeomFromText(@ls));
          +----------------------------+
          | GLength(GeomFromText(@ls)) |
          +----------------------------+
          |            2.8284271247462 |
          +----------------------------+

     `GLength()' is a nonstandard name. It corresponds to the OpenGIS
     `Length()' function.

   *  `NumPoints(LS)'

     Returns the number of `Point' objects in the `LineString' value LS.

          mysql> SET @ls = 'LineString(1 1,2 2,3 3)';
          mysql> SELECT NumPoints(GeomFromText(@ls));
          +------------------------------+
          | NumPoints(GeomFromText(@ls)) |
          +------------------------------+
          |                            3 |
          +------------------------------+

   *  `PointN(LS,N)'

     Returns the N-th `Point' in the `Linestring' value LS. Points are
     numbered beginning with 1.

          mysql> SET @ls = 'LineString(1 1,2 2,3 3)';
          mysql> SELECT AsText(PointN(GeomFromText(@ls),2));
          +-------------------------------------+
          | AsText(PointN(GeomFromText(@ls),2)) |
          +-------------------------------------+
          | POINT(2 2)                          |
          +-------------------------------------+

   *  `StartPoint(LS)'

     Returns the `Point' that is the start point of the `LineString'
     value LS.

          mysql> SET @ls = 'LineString(1 1,2 2,3 3)';
          mysql> SELECT AsText(StartPoint(GeomFromText(@ls)));
          +---------------------------------------+
          | AsText(StartPoint(GeomFromText(@ls))) |
          +---------------------------------------+
          | POINT(1 1)                            |
          +---------------------------------------+

The OpenGIS specification also defines the following function, which
MySQL does not implement:

   *  `IsRing(LS)'

     Returns 1 if the `LineString' value LS is closed (that is, its
     `StartPoint()' and `EndPoint()' values are the same) and is simple
     (does not pass through the same point more than once). Returns 0 if
     LS is not a ring, and -1 if it is `NULL'.


File: manual.info,  Node: multilinestring-property-functions,  Next: polygon-property-functions,  Prev: linestring-property-functions,  Up: geometry-property-functions

12.16.5.6 `MultiLineString' Functions
.....................................

These functions return properties of `MultiLineString' values.

   * `GLength(MLS)'

     Returns as a double-precision number the length of the
     `MultiLineString' value MLS. The length of MLS is equal to the sum
     of the lengths of its elements.

          mysql> SET @mls = 'MultiLineString((1 1,2 2,3 3),(4 4,5 5))';
          mysql> SELECT GLength(GeomFromText(@mls));
          +-----------------------------+
          | GLength(GeomFromText(@mls)) |
          +-----------------------------+
          |             4.2426406871193 |
          +-----------------------------+

     `GLength()' is a nonstandard name. It corresponds to the OpenGIS
     `Length()' function.

   *  `IsClosed(MLS)'

     Returns 1 if the `MultiLineString' value MLS is closed (that is,
     the `StartPoint()' and `EndPoint()' values are the same for each
     `LineString' in MLS). Returns 0 if MLS is not closed, and -1 if it
     is `NULL'.

          mysql> SET @mls = 'MultiLineString((1 1,2 2,3 3),(4 4,5 5))';
          mysql> SELECT IsClosed(GeomFromText(@mls));
          +------------------------------+
          | IsClosed(GeomFromText(@mls)) |
          +------------------------------+
          |                            0 |
          +------------------------------+


File: manual.info,  Node: polygon-property-functions,  Next: multipolygon-property-functions,  Prev: multilinestring-property-functions,  Up: geometry-property-functions

12.16.5.7 `Polygon' Functions
.............................

These functions return properties of `Polygon' values.

   *  `Area(POLY)'

     Returns as a double-precision number the area of the `Polygon'
     value POLY, as measured in its spatial reference system.

          mysql> SET @poly = 'Polygon((0 0,0 3,3 0,0 0),(1 1,1 2,2 1,1 1))';
          mysql> SELECT Area(GeomFromText(@poly));
          +---------------------------+
          | Area(GeomFromText(@poly)) |
          +---------------------------+
          |                         4 |
          +---------------------------+

   *  `ExteriorRing(POLY)'

     Returns the exterior ring of the `Polygon' value POLY as a
     `LineString'.

          mysql> SET @poly =
              -> 'Polygon((0 0,0 3,3 3,3 0,0 0),(1 1,1 2,2 2,2 1,1 1))';
          mysql> SELECT AsText(ExteriorRing(GeomFromText(@poly)));
          +-------------------------------------------+
          | AsText(ExteriorRing(GeomFromText(@poly))) |
          +-------------------------------------------+
          | LINESTRING(0 0,0 3,3 3,3 0,0 0)           |
          +-------------------------------------------+

   *  `InteriorRingN(POLY,N)'

     Returns the N-th interior ring for the `Polygon' value POLY as a
     `LineString'. Rings are numbered beginning with 1.

          mysql> SET @poly =
              -> 'Polygon((0 0,0 3,3 3,3 0,0 0),(1 1,1 2,2 2,2 1,1 1))';
          mysql> SELECT AsText(InteriorRingN(GeomFromText(@poly),1));
          +----------------------------------------------+
          | AsText(InteriorRingN(GeomFromText(@poly),1)) |
          +----------------------------------------------+
          | LINESTRING(1 1,1 2,2 2,2 1,1 1)              |
          +----------------------------------------------+

   *  `NumInteriorRings(POLY)'

     Returns the number of interior rings in the `Polygon' value POLY.

          mysql> SET @poly =
              -> 'Polygon((0 0,0 3,3 3,3 0,0 0),(1 1,1 2,2 2,2 1,1 1))';
          mysql> SELECT NumInteriorRings(GeomFromText(@poly));
          +---------------------------------------+
          | NumInteriorRings(GeomFromText(@poly)) |
          +---------------------------------------+
          |                                     1 |
          +---------------------------------------+


File: manual.info,  Node: multipolygon-property-functions,  Next: geometrycollection-property-functions,  Prev: polygon-property-functions,  Up: geometry-property-functions

12.16.5.8 `MultiPolygon' Functions
..................................

These functions return properties of `MultiPolygon' values.

   * `Area(MPOLY)'

     Returns as a double-precision number the area of the
     `MultiPolygon' value MPOLY, as measured in its spatial reference
     system.

          mysql> SET @mpoly =
              -> 'MultiPolygon(((0 0,0 3,3 3,3 0,0 0),(1 1,1 2,2 2,2 1,1 1)))';
          mysql> SELECT Area(GeomFromText(@mpoly));
          +----------------------------+
          | Area(GeomFromText(@mpoly)) |
          +----------------------------+
          |                          8 |
          +----------------------------+

The OpenGIS specification also defines the following functions, which
MySQL does not implement:

   *  `Centroid(MPOLY)'

     Returns the mathematical centroid for the `MultiPolygon' value
     MPOLY as a `Point'. The result is not guaranteed to be on the
     `MultiPolygon'.

   * `PointOnSurface(MPOLY)'

     Returns a `Point' value that is guaranteed to be on the
     `MultiPolygon' value MPOLY.


File: manual.info,  Node: geometrycollection-property-functions,  Prev: multipolygon-property-functions,  Up: geometry-property-functions

12.16.5.9 `GeometryCollection' Functions
........................................

These functions return properties of `GeometryCollection' values.

   *  `GeometryN(GC,N)'

     Returns the N-th geometry in the `GeometryCollection' value GC.
     Geometries are numbered beginning with 1.

          mysql> SET @gc = 'GeometryCollection(Point(1 1),LineString(2 2, 3 3))';
          mysql> SELECT AsText(GeometryN(GeomFromText(@gc),1));
          +----------------------------------------+
          | AsText(GeometryN(GeomFromText(@gc),1)) |
          +----------------------------------------+
          | POINT(1 1)                             |
          +----------------------------------------+

   *  `NumGeometries(GC)'

     Returns the number of geometries in the `GeometryCollection' value
     GC.

          mysql> SET @gc = 'GeometryCollection(Point(1 1),LineString(2 2, 3 3))';
          mysql> SELECT NumGeometries(GeomFromText(@gc));
          +----------------------------------+
          | NumGeometries(GeomFromText(@gc)) |
          +----------------------------------+
          |                                2 |
          +----------------------------------+


File: manual.info,  Node: functions-that-create-new-geometries-from-existing-ones,  Next: functions-for-testing-spatial-relations-between-geometric-objects,  Prev: geometry-property-functions,  Up: spatial-analysis-functions

12.16.5.10 Functions That Create New Geometries from Existing Ones
..................................................................

* Menu:

* functions-that-produce-new-geometries::  Geometry Functions That Produce New Geometries
* spatial-operators::            Spatial Operators

The following sections describe functions that take geometry values as
arguments and return new geometry values.


File: manual.info,  Node: functions-that-produce-new-geometries,  Next: spatial-operators,  Prev: functions-that-create-new-geometries-from-existing-ones,  Up: functions-that-create-new-geometries-from-existing-ones

12.16.5.11 Geometry Functions That Produce New Geometries
.........................................................

*Note geometry-property-functions::, discusses several functions that
construct new geometries from existing ones. See that section for
descriptions of these functions:

   * `Envelope(G)'

   * `StartPoint(LS)'

   * `EndPoint(LS)'

   * `PointN(LS,N)'

   * `ExteriorRing(POLY)'

   * `InteriorRingN(POLY,N)'

   * `GeometryN(GC,N)'


File: manual.info,  Node: spatial-operators,  Prev: functions-that-produce-new-geometries,  Up: functions-that-create-new-geometries-from-existing-ones

12.16.5.12 Spatial Operators
............................

OpenGIS proposes a number of other functions that can produce
geometries. They are designed to implement spatial operators.

These functions are not implemented in MySQL.

   *  `Buffer(G,D)'

     Returns a geometry that represents all points whose distance from
     the geometry value G is less than or equal to a distance of D.

   *  `ConvexHull(G)'

     Returns a geometry that represents the convex hull of the geometry
     value G.

   *  `Difference(G1,G2)'

     Returns a geometry that represents the point set difference of the
     geometry value G1 with G2.

   *  `Intersection(G1,G2)'

     Returns a geometry that represents the point set intersection of
     the geometry values G1 with G2.

   *  `SymDifference(G1,G2)'

     Returns a geometry that represents the point set symmetric
     difference of the geometry value G1 with G2.

   *  `Union(G1,G2)'

     Returns a geometry that represents the point set union of the
     geometry values G1 and G2.


File: manual.info,  Node: functions-for-testing-spatial-relations-between-geometric-objects,  Prev: functions-that-create-new-geometries-from-existing-ones,  Up: spatial-analysis-functions

12.16.5.13 Functions for Testing Spatial Relations Between Geometric Objects
............................................................................

* Menu:

* relations-on-geometry-mbr::    Relations on Geometry Minimal Bounding Rectangles (MBRs)
* functions-that-test-spatial-relationships-between-geometries::  Functions That Test Spatial Relationships Between Geometries

The functions described in these sections take two geometries as input
parameters and return a qualitative or quantitative relation between
them.


File: manual.info,  Node: relations-on-geometry-mbr,  Next: functions-that-test-spatial-relationships-between-geometries,  Prev: functions-for-testing-spatial-relations-between-geometric-objects,  Up: functions-for-testing-spatial-relations-between-geometric-objects

12.16.5.14 Relations on Geometry Minimal Bounding Rectangles (MBRs)
...................................................................

MySQL provides several functions that test relations between minimal
bounding rectangles of two geometries `g1' and `g2'. The return values
1 and 0 indicate true and false, respectively.

   *  `MBRContains(G1,G2)'

     Returns 1 or 0 to indicate whether the Minimum Bounding Rectangle
     of G1 contains the Minimum Bounding Rectangle of G2. This tests
     the opposite relationship as `MBRWithin()'.

          mysql> SET @g1 = GeomFromText('Polygon((0 0,0 3,3 3,3 0,0 0))');
          mysql> SET @g2 = GeomFromText('Point(1 1)');
          mysql> SELECT MBRContains(@g1,@g2), MBRContains(@g2,@g1);
          ----------------------+----------------------+
          | MBRContains(@g1,@g2) | MBRContains(@g2,@g1) |
          +----------------------+----------------------+
          |                    1 |                    0 |
          +----------------------+----------------------+

   *  `MBRDisjoint(G1,G2)'

     Returns 1 or 0 to indicate whether the Minimum Bounding Rectangles
     of the two geometries G1 and G2 are disjoint (do not intersect).

   *  `MBREqual(G1,G2)'

     Returns 1 or 0 to indicate whether the Minimum Bounding Rectangles
     of the two geometries G1 and G2 are the same.

   *  `MBRIntersects(G1,G2)'

     Returns 1 or 0 to indicate whether the Minimum Bounding Rectangles
     of the two geometries G1 and G2 intersect.

   *  `MBROverlaps(G1,G2)'

     Returns 1 or 0 to indicate whether the Minimum Bounding Rectangles
     of the two geometries G1 and G2 overlap. The term _spatially
     overlaps_ is used if two geometries intersect and their
     intersection results in a geometry of the same dimension but not
     equal to either of the given geometries.

   *  `MBRTouches(G1,G2)'

     Returns 1 or 0 to indicate whether the Minimum Bounding Rectangles
     of the two geometries G1 and G2 touch. Two geometries _spatially
     touch_ if the interiors of the geometries do not intersect, but
     the boundary of one of the geometries intersects either the
     boundary or the interior of the other.

   *  `MBRWithin(G1,G2)'

     Returns 1 or 0 to indicate whether the Minimum Bounding Rectangle
     of G1 is within the Minimum Bounding Rectangle of G2. This tests
     the opposite relationship as `MBRContains()'.

          mysql> SET @g1 = GeomFromText('Polygon((0 0,0 3,3 3,3 0,0 0))');
          mysql> SET @g2 = GeomFromText('Polygon((0 0,0 5,5 5,5 0,0 0))');
          mysql> SELECT MBRWithin(@g1,@g2), MBRWithin(@g2,@g1);
          +--------------------+--------------------+
          | MBRWithin(@g1,@g2) | MBRWithin(@g2,@g1) |
          +--------------------+--------------------+
          |                  1 |                  0 |
          +--------------------+--------------------+


File: manual.info,  Node: functions-that-test-spatial-relationships-between-geometries,  Prev: relations-on-geometry-mbr,  Up: functions-for-testing-spatial-relations-between-geometric-objects

12.16.5.15 Functions That Test Spatial Relationships Between Geometries
.......................................................................

The OpenGIS specification defines the following functions.  They test
the relationship between two geometry values `g1' and `g2'.

The return values 1 and 0 indicate true and false, respectively.

*Note*:

Currently, MySQL does not implement these functions according to the
specification. Those that are implemented return the same result as the
corresponding MBR-based functions.

   *  `Contains(G1,G2)'

     Returns 1 or 0 to indicate whether G1 completely contains G2. This
     tests the opposite relationship as `Within()'.

   *  `Crosses(G1,G2)'

     Returns 1 if G1 spatially crosses G2. Returns `NULL' if `g1' is a
     `Polygon' or a `MultiPolygon', or if G2 is a `Point' or a
     `MultiPoint'. Otherwise, returns 0.

     The term _spatially crosses_ denotes a spatial relation between
     two given geometries that has the following properties:

        * The two geometries intersect

        * Their intersection results in a geometry that has a dimension
          that is one less than the maximum dimension of the two given
          geometries

        * Their intersection is not equal to either of the two given
          geometries

   *  `Disjoint(G1,G2)'

     Returns 1 or 0 to indicate whether G1 is spatially disjoint from
     (does not intersect) G2.

   *  `Equals(G1,G2)'

     Returns 1 or 0 to indicate whether G1 is spatially equal to G2.

   *  `Intersects(G1,G2)'

     Returns 1 or 0 to indicate whether G1 spatially intersects G2.

   *  `Overlaps(G1,G2)'

     Returns 1 or 0 to indicate whether G1 spatially overlaps G2. The
     term _spatially overlaps_ is used if two geometries intersect and
     their intersection results in a geometry of the same dimension but
     not equal to either of the given geometries.

   *  `Touches(G1,G2)'

     Returns 1 or 0 to indicate whether G1 spatially touches G2. Two
     geometries _spatially touch_ if the interiors of the geometries do
     not intersect, but the boundary of one of the geometries
     intersects either the boundary or the interior of the other.

   *  `Within(G1,G2)'

     Returns 1 or 0 to indicate whether G1 is spatially within G2. This
     tests the opposite relationship as `Contains()'.


File: manual.info,  Node: optimizing-spatial-analysis,  Next: mysql-gis-conformance-and-compatibility,  Prev: spatial-analysis-functions,  Up: spatial-extensions

12.16.6 Optimizing Spatial Analysis
-----------------------------------

* Menu:

* creating-spatial-indexes::     Creating Spatial Indexes
* using-a-spatial-index::        Using a Spatial Index

For *Note `MyISAM': myisam-storage-engine. tables, Search operations in
nonspatial databases can be optimized using `SPATIAL' indexes. This is
true for spatial databases as well. With the help of a great variety of
multi-dimensional indexing methods that have previously been designed,
it is possible to optimize spatial searches. The most typical of these
are:

   * Point queries that search for all objects that contain a given
     point

   * Region queries that search for all objects that overlap a given
     region

MySQL uses *R-Trees with quadratic splitting* for `SPATIAL' indexes on
spatial columns. A `SPATIAL' index is built using the MBR of a
geometry. For most geometries, the MBR is a minimum rectangle that
surrounds the geometries. For a horizontal or a vertical linestring,
the MBR is a rectangle degenerated into the linestring. For a point,
the MBR is a rectangle degenerated into the point.

It is also possible to create normal indexes on spatial columns.  In a
non-`SPATIAL' index, you must declare a prefix for any spatial column
except for `POINT' columns.

`MyISAM' supports both `SPATIAL' and non-`SPATIAL' indexes. Other
storage engines support non-`SPATIAL' indexes, as described in *Note
create-index::.


File: manual.info,  Node: creating-spatial-indexes,  Next: using-a-spatial-index,  Prev: optimizing-spatial-analysis,  Up: optimizing-spatial-analysis

12.16.6.1 Creating Spatial Indexes
..................................

For *Note `MyISAM': myisam-storage-engine. tables, MySQL can create
spatial indexes using syntax similar to that for creating regular
indexes, but extended with the `SPATIAL' keyword. Currently, columns in
spatial indexes must be declared `NOT NULL'.  The following examples
demonstrate how to create spatial indexes:

   * With *Note `CREATE TABLE': create-table.:

          CREATE TABLE geom (g GEOMETRY NOT NULL, SPATIAL INDEX(g)) ENGINE=MyISAM;

   * With *Note `ALTER TABLE': alter-table.:

          ALTER TABLE geom ADD SPATIAL INDEX(g);

   * With *Note `CREATE INDEX': create-index.:

          CREATE SPATIAL INDEX sp_index ON geom (g);

For `MyISAM' tables, `SPATIAL INDEX' creates an R-tree index. For
storage engines that support nonspatial indexing of spatial columns,
the engine creates a B-tree index. A B-tree index on spatial values
will be useful for exact-value lookups, but not for range scans.

For more information on indexing spatial columns, see *Note
create-index::.

To drop spatial indexes, use *Note `ALTER TABLE': alter-table. or *Note
`DROP INDEX': drop-index.:

   * With *Note `ALTER TABLE': alter-table.:

          ALTER TABLE geom DROP INDEX g;

   * With *Note `DROP INDEX': drop-index.:

          DROP INDEX sp_index ON geom;

Example: Suppose that a table `geom' contains more than 32,000
geometries, which are stored in the column `g' of type `GEOMETRY'. The
table also has an `AUTO_INCREMENT' column `fid' for storing object ID
values.

     mysql> DESCRIBE geom;
     +-------+----------+------+-----+---------+----------------+
     | Field | Type     | Null | Key | Default | Extra          |
     +-------+----------+------+-----+---------+----------------+
     | fid   | int(11)  |      | PRI | NULL    | auto_increment |
     | g     | geometry |      |     |         |                |
     +-------+----------+------+-----+---------+----------------+
     2 rows in set (0.00 sec)

     mysql> SELECT COUNT(*) FROM geom;
     +----------+
     | count(*) |
     +----------+
     |    32376 |
     +----------+
     1 row in set (0.00 sec)

To add a spatial index on the column `g', use this statement:

     mysql> ALTER TABLE geom ADD SPATIAL INDEX(g);
     Query OK, 32376 rows affected (4.05 sec)
     Records: 32376  Duplicates: 0  Warnings: 0


File: manual.info,  Node: using-a-spatial-index,  Prev: creating-spatial-indexes,  Up: optimizing-spatial-analysis

12.16.6.2 Using a Spatial Index
...............................

The optimizer investigates whether available spatial indexes can be
involved in the search for queries that use a function such as
`MBRContains()' or `MBRWithin()' in the `WHERE' clause. The following
query finds all objects that are in the given rectangle:

     mysql> SET @poly =
         -> 'Polygon((30000 15000,31000 15000,31000 16000,30000 16000,30000 15000))';
     mysql> SELECT fid,AsText(g) FROM geom WHERE
         -> MBRContains(GeomFromText(@poly),g);
     +-----+---------------------------------------------------------------+
     | fid | AsText(g)                                                     |
     +-----+---------------------------------------------------------------+
     |  21 | LINESTRING(30350.4 15828.8,30350.6 15845,30333.8 15845,30 ... |
     |  22 | LINESTRING(30350.6 15871.4,30350.6 15887.8,30334 15887.8, ... |
     |  23 | LINESTRING(30350.6 15914.2,30350.6 15930.4,30334 15930.4, ... |
     |  24 | LINESTRING(30290.2 15823,30290.2 15839.4,30273.4 15839.4, ... |
     |  25 | LINESTRING(30291.4 15866.2,30291.6 15882.4,30274.8 15882. ... |
     |  26 | LINESTRING(30291.6 15918.2,30291.6 15934.4,30275 15934.4, ... |
     | 249 | LINESTRING(30337.8 15938.6,30337.8 15946.8,30320.4 15946. ... |
     |   1 | LINESTRING(30250.4 15129.2,30248.8 15138.4,30238.2 15136. ... |
     |   2 | LINESTRING(30220.2 15122.8,30217.2 15137.8,30207.6 15136, ... |
     |   3 | LINESTRING(30179 15114.4,30176.6 15129.4,30167 15128,3016 ... |
     |   4 | LINESTRING(30155.2 15121.4,30140.4 15118.6,30142 15109,30 ... |
     |   5 | LINESTRING(30192.4 15085,30177.6 15082.2,30179.2 15072.4, ... |
     |   6 | LINESTRING(30244 15087,30229 15086.2,30229.4 15076.4,3024 ... |
     |   7 | LINESTRING(30200.6 15059.4,30185.6 15058.6,30186 15048.8, ... |
     |  10 | LINESTRING(30179.6 15017.8,30181 15002.8,30190.8 15003.6, ... |
     |  11 | LINESTRING(30154.2 15000.4,30168.6 15004.8,30166 15014.2, ... |
     |  13 | LINESTRING(30105 15065.8,30108.4 15050.8,30118 15053,3011 ... |
     | 154 | LINESTRING(30276.2 15143.8,30261.4 15141,30263 15131.4,30 ... |
     | 155 | LINESTRING(30269.8 15084,30269.4 15093.4,30258.6 15093,30 ... |
     | 157 | LINESTRING(30128.2 15011,30113.2 15010.2,30113.6 15000.4, ... |
     +-----+---------------------------------------------------------------+
     20 rows in set (0.00 sec)

Use *Note `EXPLAIN': explain. to check the way this query is executed:

     mysql> SET @poly =
         -> 'Polygon((30000 15000,31000 15000,31000 16000,30000 16000,30000 15000))';
     mysql> EXPLAIN SELECT fid,AsText(g) FROM geom WHERE
         -> MBRContains(GeomFromText(@poly),g)\G
     *************************** 1. row ***************************
                id: 1
       select_type: SIMPLE
             table: geom
              type: range
     possible_keys: g
               key: g
           key_len: 32
               ref: NULL
              rows: 50
             Extra: Using where
     1 row in set (0.00 sec)

Check what would happen without a spatial index:

     mysql> SET @poly =
         -> 'Polygon((30000 15000,31000 15000,31000 16000,30000 16000,30000 15000))';
     mysql> EXPLAIN SELECT fid,AsText(g) FROM g IGNORE INDEX (g) WHERE
         -> MBRContains(GeomFromText(@poly),g)\G
     *************************** 1. row ***************************
                id: 1
       select_type: SIMPLE
             table: geom
              type: ALL
     possible_keys: NULL
               key: NULL
           key_len: NULL
               ref: NULL
              rows: 32376
             Extra: Using where
     1 row in set (0.00 sec)

Executing the *Note `SELECT': select. statement without the spatial
index yields the same result but causes the execution time to rise from
0.00 seconds to 0.46 seconds:

     mysql> SET @poly =
         -> 'Polygon((30000 15000,31000 15000,31000 16000,30000 16000,30000 15000))';
     mysql> SELECT fid,AsText(g) FROM geom IGNORE INDEX (g) WHERE
         -> MBRContains(GeomFromText(@poly),g);
     +-----+---------------------------------------------------------------+
     | fid | AsText(g)                                                     |
     +-----+---------------------------------------------------------------+
     |   1 | LINESTRING(30250.4 15129.2,30248.8 15138.4,30238.2 15136. ... |
     |   2 | LINESTRING(30220.2 15122.8,30217.2 15137.8,30207.6 15136, ... |
     |   3 | LINESTRING(30179 15114.4,30176.6 15129.4,30167 15128,3016 ... |
     |   4 | LINESTRING(30155.2 15121.4,30140.4 15118.6,30142 15109,30 ... |
     |   5 | LINESTRING(30192.4 15085,30177.6 15082.2,30179.2 15072.4, ... |
     |   6 | LINESTRING(30244 15087,30229 15086.2,30229.4 15076.4,3024 ... |
     |   7 | LINESTRING(30200.6 15059.4,30185.6 15058.6,30186 15048.8, ... |
     |  10 | LINESTRING(30179.6 15017.8,30181 15002.8,30190.8 15003.6, ... |
     |  11 | LINESTRING(30154.2 15000.4,30168.6 15004.8,30166 15014.2, ... |
     |  13 | LINESTRING(30105 15065.8,30108.4 15050.8,30118 15053,3011 ... |
     |  21 | LINESTRING(30350.4 15828.8,30350.6 15845,30333.8 15845,30 ... |
     |  22 | LINESTRING(30350.6 15871.4,30350.6 15887.8,30334 15887.8, ... |
     |  23 | LINESTRING(30350.6 15914.2,30350.6 15930.4,30334 15930.4, ... |
     |  24 | LINESTRING(30290.2 15823,30290.2 15839.4,30273.4 15839.4, ... |
     |  25 | LINESTRING(30291.4 15866.2,30291.6 15882.4,30274.8 15882. ... |
     |  26 | LINESTRING(30291.6 15918.2,30291.6 15934.4,30275 15934.4, ... |
     | 154 | LINESTRING(30276.2 15143.8,30261.4 15141,30263 15131.4,30 ... |
     | 155 | LINESTRING(30269.8 15084,30269.4 15093.4,30258.6 15093,30 ... |
     | 157 | LINESTRING(30128.2 15011,30113.2 15010.2,30113.6 15000.4, ... |
     | 249 | LINESTRING(30337.8 15938.6,30337.8 15946.8,30320.4 15946. ... |
     +-----+---------------------------------------------------------------+
     20 rows in set (0.46 sec)


File: manual.info,  Node: mysql-gis-conformance-and-compatibility,  Prev: optimizing-spatial-analysis,  Up: spatial-extensions

12.16.7 MySQL Conformance and Compatibility
-------------------------------------------

MySQL does not yet implement the following GIS features:

   * Additional Metadata Views

     OpenGIS specifications propose several additional metadata views.
     For example, a system view named `GEOMETRY_COLUMNS' contains a
     description of geometry columns, one row for each geometry column
     in the database.

   * The OpenGIS function `Length()' on `LineString' and
     `MultiLineString' currently should be called in MySQL as
     `GLength()'

     The problem is that there is an existing SQL function `Length()'
     that calculates the length of string values, and sometimes it is
     not possible to distinguish whether the function is called in a
     textual or spatial context. We need either to solve this somehow,
     or decide on another function name.


File: manual.info,  Node: precision-math,  Prev: spatial-extensions,  Up: functions

12.17 Precision Math
====================

* Menu:

* precision-math-numbers::       Types of Numeric Values
* precision-math-decimal-changes::  `DECIMAL' Data Type Changes
* precision-math-expressions::   Expression Handling
* precision-math-rounding::      Rounding Behavior
* precision-math-examples::      Precision Math Examples

MySQL 5.0 introduces precision math: numeric value handling that
results in more accurate results and more control over invalid values
than in earlier versions of MySQL. Precision math is based on two
implementation changes:

   * The introduction of SQL modes in MySQL 5.0 that control how strict
     the server is about accepting or rejecting invalid data.

   * The introduction in MySQL 5.0.3 of a library for fixed-point
     arithmetic.

These changes result in the following characteristics for numeric
operations and provide improved compliance with standard SQL:

   * *Precise calculations*: For exact-value numbers, calculations do
     not introduce floating-point errors. Instead, exact precision is
     used. For example, MySQL treats a number such as `.0001' as an
     exact value rather than as an approximation, and summing it 10,000
     times produces a result of exactly `1', not a value that is merely
     `close' to 1.

   * *Well-defined rounding behavior*: For exact-value numbers, the
     result of `ROUND()' depends on its argument, not on environmental
     factors such as how the underlying C library works.

   * *Platform independence*: Operations on exact numeric values are
     the same across different platforms such as Windows and Unix.

   * *Control over handling of invalid values*: Overflow and division
     by zero are detectable and can be treated as errors. For example,
     you can treat a value that is too large for a column as an error
     rather than having the value truncated to lie within the range of
     the column's data type. Similarly, you can treat division by zero
     as an error rather than as an operation that produces a result of
     `NULL'. The choice of which approach to take is determined by the
     setting of the server SQL mode.

The following discussion covers several aspects of how precision math
works, including possible incompatibilities with older applications. At
the end, some examples are given that demonstrate how MySQL 5.0 handles
numeric operations precisely. For information about controlling the SQL
mode, see *Note server-sql-mode::.


File: manual.info,  Node: precision-math-numbers,  Next: precision-math-decimal-changes,  Prev: precision-math,  Up: precision-math

12.17.1 Types of Numeric Values
-------------------------------

The scope of precision math for exact-value operations includes the
exact-value data types (*Note `DECIMAL': numeric-types.  and integer
types) and exact-value numeric literals.  Approximate-value data types
and numeric literals are handled as floating-point numbers.

Exact-value numeric literals have an integer part or fractional part,
or both. They may be signed. Examples: `1', `.2', `3.4', `-5', `-6.78',
`+9.10'.

Approximate-value numeric literals are represented in scientific
notation with a mantissa and exponent. Either or both parts may be
signed. Examples: `1.2E3', `1.2E-3', `-1.2E3', `-1.2E-3'.

Two numbers that look similar may be treated differently. For example,
`2.34' is an exact-value (fixed-point) number, whereas `2.34E0' is an
approximate-value (floating-point) number.

The *Note `DECIMAL': numeric-types. data type is a fixed-point type and
calculations are exact. In MySQL, the *Note `DECIMAL': numeric-types.
type has several synonyms: *Note `NUMERIC': numeric-types, *Note `DEC':
numeric-types, *Note `FIXED': numeric-types. The integer types also are
exact-value types.

The *Note `FLOAT': numeric-types. and *Note `DOUBLE': numeric-types.
data types are floating-point types and calculations are approximate.
In MySQL, types that are synonymous with *Note `FLOAT': numeric-types.
or *Note `DOUBLE': numeric-types. are *Note `DOUBLE PRECISION':
numeric-types. and *Note `REAL': numeric-types.


File: manual.info,  Node: precision-math-decimal-changes,  Next: precision-math-expressions,  Prev: precision-math-numbers,  Up: precision-math

12.17.2 `DECIMAL' Data Type Changes
-----------------------------------

This section discusses the characteristics of the *Note `DECIMAL':
numeric-types. data type (and its synonyms) as of MySQL 5.0.3, with
particular regard to the following topics:

   * Maximum number of digits

   * Storage format

   * Storage requirements

   * The nonstandard MySQL extension to the upper range of *Note
     `DECIMAL': numeric-types. columns

Some of these characteristics result in possible incompatibilities for
applications that are written for older versions of MySQL.  These
incompatibilities are noted throughout this section.

The declaration syntax for a *Note `DECIMAL': numeric-types. column
remains `DECIMAL(M,D)', although the range of values for the arguments
has changed somewhat:

   * M is the maximum number of digits (the precision). It has a range
     of 1 to 65. This introduces a possible incompatibility for older
     applications, because previous versions of MySQL permit a range of
     1 to 254. (The precision of 65 digits actually applies as of MySQL
     5.0.6.  From 5.0.3 to 5.0.5, the precision is 64 digits.)

   * D is the number of digits to the right of the decimal point (the
     scale). It has a range of 0 to 30 and must be no larger than M.

The maximum value of 65 for M means that calculations on *Note
`DECIMAL': numeric-types. values are accurate up to 65 digits. This
limit of 65 digits of precision also applies to exact-value numeric
literals, so the maximum range of such literals differs from before.
(Prior to MySQL 5.0.3, decimal values could have up to 254 digits.
However, calculations were done using floating-point and thus were
approximate, not exact.) This change in the range of literal values is
another possible source of incompatibility for older applications.

Values for *Note `DECIMAL': numeric-types. columns no longer are
represented as strings that require 1 byte per digit or sign character.
Instead, a binary format is used that packs nine decimal digits into 4
bytes. This change to *Note `DECIMAL': numeric-types. storage format
changes the storage requirements as well. The storage requirements for
the integer and fractional parts of each value are determined
separately. Each multiple of nine digits requires 4 bytes, and any
remaining digits require some fraction of 4 bytes. The storage required
for remaining digits is given by the following table.

Leftover Digits    Number of Bytes
0                  0
1-2                1
3-4                2
5-6                3
7-9                4

For example, a `DECIMAL(18,9)' column has nine digits on either side of
the decimal point, so the integer part and the fractional part each
require 4 bytes. A `DECIMAL(20,6)' column has fourteen integer digits
and six fractional digits. The integer digits require four bytes for
nine of the digits and 3 bytes for the remaining five digits. The six
fractional digits require 3 bytes.

As a result of the change from string to numeric format for *Note
`DECIMAL': numeric-types. storage, *Note `DECIMAL': numeric-types.
columns no longer store a leading `+' or `-' character or leading `0'
digits. Before MySQL 5.0.3, if you inserted `+0003.1' into a
`DECIMAL(5,1)' column, it was stored as `+0003.1'. As of MySQL 5.0.3,
it is stored as `3.1'. For negative numbers, a literal `-' character is
no longer stored. Applications that rely on the older behavior must be
modified to account for this change.

The change of storage format also means that *Note `DECIMAL':
numeric-types. columns no longer support the nonstandard extension that
permitted values larger than the range implied by the column
definition. Formerly, 1 byte was allocated for storing the sign
character. For positive values that needed no sign byte, MySQL
permitted an extra digit to be stored instead. For example, a
`DECIMAL(3,0)' column must support a range of at least ` -999' to
`999', but MySQL would permit storing values from `1000' to `9999' as
well, by using the sign byte to store an extra digit. This extension to
the upper range of *Note `DECIMAL': numeric-types. columns is no longer
supported. As of MySQL 5.0.3, a `DECIMAL(M,D)' column permits at most M
- D digits to the left of the decimal point. This can result in an
incompatibility if an application has a reliance on MySQL permitting
`too-large' values.

The SQL standard requires that the precision of `NUMERIC(M,D)' be
_exactly_ M digits. For `DECIMAL(M,D)', the standard requires a
precision of at least M digits but permits more. In MySQL,
`DECIMAL(M,D)' and `NUMERIC(M,D)' are the same, and both have a
precision of exactly M digits.

Summary of incompatibilities:

The following list summarizes the incompatibilities that result from
changes to *Note `DECIMAL': numeric-types. column and value handling.
You can use it as guide when porting older applications for use with
MySQL 5.0.3 and up.

   * For `DECIMAL(M,D)', the maximum M is 65, not 254.

   * Calculations involving exact-value decimal numbers are accurate to
     65 digits. This is fewer than the maximum number of digits
     permitted before MySQL 5.0.3 (254 digits), but the exact-value
     precision is greater. Calculations formerly were done with
     double-precision floating-point, which has a precision of 52 bits
     (about 15 decimal digits).

   * The nonstandard MySQL extension to the upper range of *Note
     `DECIMAL': numeric-types. columns is no longer supported.

   * Leading ``+'' and ``0'' characters are not stored.

The behavior used by the server for *Note `DECIMAL': numeric-types.
columns in a table depends on the version of MySQL used to create the
table. If your server is from MySQL 5.0.3 or higher, but a table that
was created before 5.0.3 has *Note `DECIMAL': numeric-types. columns,
the old behavior still applies to those columns. To convert the table to
the newer *Note `DECIMAL': numeric-types. format, dump it with *Note
`mysqldump': mysqldump. and reload it.


File: manual.info,  Node: precision-math-expressions,  Next: precision-math-rounding,  Prev: precision-math-decimal-changes,  Up: precision-math

12.17.3 Expression Handling
---------------------------

With precision math, exact-value numbers are used as given whenever
possible. For example, numbers in comparisons are used exactly as given
without a change in value. In strict SQL mode, for *Note `INSERT':
insert. into a column with an exact data type (*Note `DECIMAL':
numeric-types. or integer), a number is inserted with its exact value
if it is within the column range. When retrieved, the value should be
the same as what was inserted. (Without strict mode, truncation for
*Note `INSERT': insert. is permissible.)

Handling of a numeric expression depends on what kind of values the
expression contains:

   * If any approximate values are present, the expression is
     approximate and is evaluated using floating-point arithmetic.

   * If no approximate values are present, the expression contains only
     exact values. If any exact value contains a fractional part (a
     value following the decimal point), the expression is evaluated
     using *Note `DECIMAL': numeric-types. exact arithmetic and has a
     precision of 65 digits. The term `exact' is subject to the limits
     of what can be represented in binary. For example, `1.0/3.0' can
     be approximated in decimal notation as `.333...', but not written
     as an exact number, so `(1.0/3.0)*3.0' does not evaluate to
     exactly `1.0'.

   * Otherwise, the expression contains only integer values. The
     expression is exact and is evaluated using integer arithmetic and
     has a precision the same as *Note `BIGINT': numeric-types. (64
     bits).

If a numeric expression contains any strings, they are converted to
double-precision floating-point values and the expression is
approximate.

Inserts into numeric columns are affected by the SQL mode, which is
controlled by the `sql_mode' system variable. (See *Note
server-sql-mode::.) The following discussion mentions strict mode
(selected by the `STRICT_ALL_TABLES' or `STRICT_TRANS_TABLES' mode
values) and `ERROR_FOR_DIVISION_BY_ZERO'.  To turn on all restrictions,
you can simply use `TRADITIONAL' mode, which includes both strict mode
values and `ERROR_FOR_DIVISION_BY_ZERO':

     mysql> SET sql_mode='TRADITIONAL';

If a number is inserted into an exact type column (*Note `DECIMAL':
numeric-types. or integer), it is inserted with its exact value if it
is within the column range.

If the value has too many digits in the fractional part, rounding
occurs and a warning is generated. Rounding is done as described in
*Note precision-math-rounding::.

If the value has too many digits in the integer part, it is too large
and is handled as follows:

   * If strict mode is not enabled, the value is truncated to the
     nearest legal value and a warning is generated.

   * If strict mode is enabled, an overflow error occurs.

Underflow is not detected, so underflow handing is undefined.

By default, division by zero produces a result of `NULL' and no
warning. With the `ERROR_FOR_DIVISION_BY_ZERO' SQL mode enabled, MySQL
handles division by zero differently:

   * If strict mode is not enabled, a warning occurs.

   * If strict mode is enabled, inserts and updates involving division
     by zero are prohibited, and an error occurs.

In other words, inserts and updates involving expressions that perform
division by zero can be treated as errors, but this requires
`ERROR_FOR_DIVISION_BY_ZERO' in addition to strict mode.

Suppose that we have this statement:

     INSERT INTO t SET i = 1/0;

This is what happens for combinations of strict and
`ERROR_FOR_DIVISION_BY_ZERO' modes.

`sql_mode' Value                     Result
`''' (Default)                       No warning, no error; `i' is set to
                                     `NULL'.
strict                               No warning, no error; `i' is set to
                                     `NULL'.
`ERROR_FOR_DIVISION_BY_ZERO'         Warning, no error; `i' is set to
                                     `NULL'.
strict,`ERROR_FOR_DIVISION_BY_ZERO'  Error condition; no row is inserted.

For inserts of strings into numeric columns, conversion from string to
number is handled as follows if the string has nonnumeric contents:

   * A string that does not begin with a number cannot be used as a
     number and produces an error in strict mode, or a warning
     otherwise. This includes the empty string.

   * A string that begins with a number can be converted, but the
     trailing nonnumeric portion is truncated. If the truncated portion
     contains anything other than spaces, this produces an error in
     strict mode, or a warning otherwise.


File: manual.info,  Node: precision-math-rounding,  Next: precision-math-examples,  Prev: precision-math-expressions,  Up: precision-math

12.17.4 Rounding Behavior
-------------------------

This section discusses precision math rounding for the `ROUND()'
function and for inserts into columns with exact-value types (*Note
`DECIMAL': numeric-types. and integer).

The `ROUND()' function rounds differently depending on whether its
argument is exact or approximate:

   * For exact-value numbers, `ROUND()' uses the `round half up' rule:
     A value with a fractional part of .5 or greater is rounded up to
     the next integer if positive or down to the next integer if
     negative. (In other words, it is rounded away from zero.) A value
     with a fractional part less than .5 is rounded down to the next
     integer if positive or up to the next integer if negative.

   * For approximate-value numbers, the result depends on the C
     library. On many systems, this means that `ROUND()' uses the `round
     to nearest even' rule: A value with any fractional part is rounded
     to the nearest even integer.

The following example shows how rounding differs for exact and
approximate values:

     mysql> SELECT ROUND(2.5), ROUND(25E-1);
     +------------+--------------+
     | ROUND(2.5) | ROUND(25E-1) |
     +------------+--------------+
     | 3          |            2 |
     +------------+--------------+

For inserts into a *Note `DECIMAL': numeric-types. or integer column,
the target is an exact data type, so rounding uses `round half up,'
regardless of whether the value to be inserted is exact or approximate:

     mysql> CREATE TABLE t (d DECIMAL(10,0));
     Query OK, 0 rows affected (0.00 sec)

     mysql> INSERT INTO t VALUES(2.5),(2.5E0);
     Query OK, 2 rows affected, 2 warnings (0.00 sec)
     Records: 2  Duplicates: 0  Warnings: 2

     mysql> SELECT d FROM t;
     +------+
     | d    |
     +------+
     | 3    |
     | 3    |
     +------+


File: manual.info,  Node: precision-math-examples,  Prev: precision-math-rounding,  Up: precision-math

12.17.5 Precision Math Examples
-------------------------------

This section provides some examples that show how precision math
improves query results in MySQL 5.0 compared to older versions.  These
examples demonstrate the principles described in *Note
precision-math-expressions::, and *Note precision-math-rounding::.

*Example 1*. Numbers are used with their exact value as given when
possible.

Before MySQL 5.0.3, numbers that are treated as floating-point values
produce inexact results:

     mysql> SELECT (.1 + .2) = .3;
     +----------------+
     | (.1 + .2) = .3 |
     +----------------+
     |              1 |
     +----------------+

As of MySQL 5.0.3, numbers are used as given when possible:

     mysql> SELECT (.1 + .2) = .3;
     +----------------+
     | (.1 + .2) = .3 |
     +----------------+
     |              1 |
     +----------------+

For floating-point values, results are inexact:

     mysql> SELECT (.1E0 + .2E0) = .3E0;
     +----------------------+
     | (.1E0 + .2E0) = .3E0 |
     +----------------------+
     |                    0 |
     +----------------------+

Another way to see the difference in exact and approximate value
handling is to add a small number to a sum many times. Consider the
following stored procedure, which adds `.0001' to a variable 1,000
times.

     CREATE PROCEDURE p ()
     BEGIN
       DECLARE i INT DEFAULT 0;
       DECLARE d DECIMAL(10,4) DEFAULT 0;
       DECLARE f FLOAT DEFAULT 0;
       WHILE i < 10000 DO
         SET d = d + .0001;
         SET f = f + .0001E0;
         SET i = i + 1;
       END WHILE;
       SELECT d, f;
     END;

The sum for both `d' and `f' logically should be 1, but that is true
only for the decimal calculation. The floating-point calculation
introduces small errors:

     +--------+------------------+
     | d      | f                |
     +--------+------------------+
     | 1.0000 | 0.99999999999991 |
     +--------+------------------+

*Example 2*. Multiplication is performed with the scale required by
standard SQL. That is, for two numbers X1 and X2 that have scale S1 and
S2, the scale of the result is `S1 + S2':

Before MySQL 5.0.3, this is what happens:

     mysql> SELECT .01 * .01;
     +-----------+
     | .01 * .01 |
     +-----------+
     |      0.00 |
     +-----------+

The displayed value is incorrect. The value was calculated correctly in
this case, but not displayed to the required scale.  To see that the
calculated value actually was .0001, try this:

     mysql> SELECT .01 * .01 + .0000;
     +-------------------+
     | .01 * .01 + .0000 |
     +-------------------+
     |            0.0001 |
     +-------------------+

As of MySQL 5.0.3, the displayed scale is correct:

     mysql> SELECT .01 * .01;
     +-----------+
     | .01 * .01 |
     +-----------+
     | 0.0001    |
     +-----------+

*Example 3*. Rounding behavior for exact-value numbers is well-defined.

Before MySQL 5.0.3, rounding behavior (for example, with the `ROUND()'
function) is dependent on the implementation of the underlying C
library. This results in inconsistencies from platform to platform. For
example, you might get a different value on Windows than on Linux, or a
different value on x86 machines than on PowerPC machines.

As of MySQL 5.0.3, rounding happens like this:

   * Rounding for exact-value columns (*Note `DECIMAL': numeric-types.
     and integer) and exact-valued numbers uses the `round half up'
     rule. Values with a fractional part of .5 or greater are rounded
     away from zero to the nearest integer, as shown here:

          mysql> SELECT ROUND(2.5), ROUND(-2.5);
          +------------+-------------+
          | ROUND(2.5) | ROUND(-2.5) |
          +------------+-------------+
          | 3          | -3          |
          +------------+-------------+

   * Rounding for floating-point values uses the C library, which on
     many systems uses the `round to nearest even' rule. Values with
     any fractional part on such systems are rounded to the nearest
     even integer:

          mysql> SELECT ROUND(2.5E0), ROUND(-2.5E0);
          +--------------+---------------+
          | ROUND(2.5E0) | ROUND(-2.5E0) |
          +--------------+---------------+
          |            2 |            -2 |
          +--------------+---------------+

*Example 4*. In strict mode, inserting a value that is out of range for
a column causes an error, rather than truncation to a legal value.

Before MySQL 5.0.2 (or in 5.0.2 and later, without strict mode),
truncation to a legal value occurs:

     mysql> CREATE TABLE t (i TINYINT);
     Query OK, 0 rows affected (0.01 sec)

     mysql> INSERT INTO t SET i = 128;
     Query OK, 1 row affected, 1 warning (0.00 sec)

     mysql> SELECT i FROM t;
     +------+
     | i    |
     +------+
     |  127 |
     +------+
     1 row in set (0.00 sec)

As of MySQL 5.0.2, an error occurs if strict mode is in effect:

     mysql> SET sql_mode='STRICT_ALL_TABLES';
     Query OK, 0 rows affected (0.00 sec)

     mysql> CREATE TABLE t (i TINYINT);
     Query OK, 0 rows affected (0.00 sec)

     mysql> INSERT INTO t SET i = 128;
     ERROR 1264 (22003): Out of range value adjusted for column 'i' at row 1

     mysql> SELECT i FROM t;
     Empty set (0.00 sec)

*Example 5*: In strict mode and with `ERROR_FOR_DIVISION_BY_ZERO' set,
division by zero causes an error, not a result of `NULL'.

Before MySQL 5.0.2 (or when not using strict mode in 5.0.2 or a later
version), division by zero has a result of `NULL':

     mysql> CREATE TABLE t (i TINYINT);
     Query OK, 0 rows affected (0.01 sec)

     mysql> INSERT INTO t SET i = 1 / 0;
     Query OK, 1 row affected (0.00 sec)

     mysql> SELECT i FROM t;
     +------+
     | i    |
     +------+
     | NULL |
     +------+
     1 row in set (0.00 sec)

As of MySQL 5.0.2, division by zero is an error if the proper SQL modes
are in effect:

     mysql> SET sql_mode='STRICT_ALL_TABLES,ERROR_FOR_DIVISION_BY_ZERO';
     Query OK, 0 rows affected (0.00 sec)

     mysql> CREATE TABLE t (i TINYINT);
     Query OK, 0 rows affected (0.00 sec)

     mysql> INSERT INTO t SET i = 1 / 0;
     ERROR 1365 (22012): Division by 0

     mysql> SELECT i FROM t;
     Empty set (0.01 sec)

*Example 6*. Exact-value literals are evaluated as exact values.

Prior to MySQL 5.0.3, exact-value and approximate-value literals both
are evaluated as double-precision floating-point values:

     mysql> SELECT VERSION();
     +------------+
     | VERSION()  |
     +------------+
     | 4.1.18-log |
     +------------+
     1 row in set (0.01 sec)

     mysql> CREATE TABLE t SELECT 2.5 AS a, 25E-1 AS b;
     Query OK, 1 row affected (0.07 sec)
     Records: 1  Duplicates: 0  Warnings: 0

     mysql> DESCRIBE t;
     +-------+-------------+------+-----+---------+-------+
     | Field | Type        | Null | Key | Default | Extra |
     +-------+-------------+------+-----+---------+-------+
     | a     | double(3,1) |      |     | 0.0     |       |
     | b     | double      |      |     | 0       |       |
     +-------+-------------+------+-----+---------+-------+
     2 rows in set (0.04 sec)

As of MySQL 5.0.3, the approximate-value literal is evaluated using
floating point, but the exact-value literal is handled as *Note
`DECIMAL': numeric-types.:

     mysql> SELECT VERSION();
     +------------+
     | VERSION()  |
     +------------+
     | 5.0.19-log |
     +------------+
     1 row in set (0.17 sec)

     mysql> CREATE TABLE t SELECT 2.5 AS a, 25E-1 AS b;
     Query OK, 1 row affected (0.19 sec)
     Records: 1  Duplicates: 0  Warnings: 0

     mysql> DESCRIBE t;
     +-------+-----------------------+------+-----+---------+-------+
     | Field | Type                  | Null | Key | Default | Extra |
     +-------+-----------------------+------+-----+---------+-------+
     | a     | decimal(2,1) unsigned | NO   |     | 0.0     |       |
     | b     | double                | NO   |     | 0       |       |
     +-------+-----------------------+------+-----+---------+-------+
     2 rows in set (0.02 sec)

*Example 7*. If the argument to an aggregate function is an exact
numeric type, the result is also an exact numeric type, with a scale at
least that of the argument.

Consider these statements:

     mysql> CREATE TABLE t (i INT, d DECIMAL, f FLOAT);
     mysql> INSERT INTO t VALUES(1,1,1);
     mysql> CREATE TABLE y SELECT AVG(i), AVG(d), AVG(f) FROM t;

Before MySQL 5.0.3, the result is a double no matter the argument type:

     mysql> DESCRIBE y;
     +--------+--------------+------+-----+---------+-------+
     | Field  | Type         | Null | Key | Default | Extra |
     +--------+--------------+------+-----+---------+-------+
     | AVG(i) | double(17,4) | YES  |     | NULL    |       |
     | AVG(d) | double(17,4) | YES  |     | NULL    |       |
     | AVG(f) | double       | YES  |     | NULL    |       |
     +--------+--------------+------+-----+---------+-------+

As of MySQL 5.0.3, the result is a double only for the floating-point
argument. For exact type arguments, the result is also an exact type:

     mysql> DESCRIBE y;
     +--------+---------------+------+-----+---------+-------+
     | Field  | Type          | Null | Key | Default | Extra |
     +--------+---------------+------+-----+---------+-------+
     | AVG(i) | decimal(14,4) | YES  |     | NULL    |       |
     | AVG(d) | decimal(14,4) | YES  |     | NULL    |       |
     | AVG(f) | double        | YES  |     | NULL    |       |
     +--------+---------------+------+-----+---------+-------+

From MySQL 5.0.3 to 5.0.6, the first two columns are `DECIMAL(64,0)'.


File: manual.info,  Node: sql-syntax,  Next: storage-engines,  Prev: functions,  Up: Top

13 SQL Statement Syntax
***********************

* Menu:

* sql-syntax-data-definition::   Data Definition Statements
* sql-syntax-data-manipulation::  Data Manipulation Statements
* sql-syntax-transactions::      MySQL Transactional and Locking Statements
* sql-syntax-replication::       Replication Statements
* sql-syntax-prepared-statements::  SQL Syntax for Prepared Statements
* sql-syntax-compound-statements::  MySQL Compound-Statement Syntax
* sql-syntax-server-administration::  Database Administration Statements
* sql-syntax-utility::           MySQL Utility Statements

This chapter describes the syntax for the SQL statements supported by
MySQL.


File: manual.info,  Node: sql-syntax-data-definition,  Next: sql-syntax-data-manipulation,  Prev: sql-syntax,  Up: sql-syntax

13.1 Data Definition Statements
===============================

* Menu:

* alter-database::               `ALTER DATABASE' Syntax
* alter-function::               `ALTER FUNCTION' Syntax
* alter-procedure::              `ALTER PROCEDURE' Syntax
* alter-table::                  `ALTER TABLE' Syntax
* alter-view::                   `ALTER VIEW' Syntax
* create-database::              `CREATE DATABASE' Syntax
* create-function::              The `CREATE FUNCTION' Statement
* create-index::                 `CREATE INDEX' Syntax
* create-procedure::             `CREATE PROCEDURE' and `CREATE FUNCTION' Syntax
* create-table::                 `CREATE TABLE' Syntax
* create-trigger::               `CREATE TRIGGER' Syntax
* create-view::                  `CREATE VIEW' Syntax
* drop-database::                `DROP DATABASE' Syntax
* drop-function::                `DROP FUNCTION' Syntax
* drop-index::                   `DROP INDEX' Syntax
* drop-procedure::               `DROP PROCEDURE' and `DROP FUNCTION' Syntax
* drop-table::                   `DROP TABLE' Syntax
* drop-trigger::                 `DROP TRIGGER' Syntax
* drop-view::                    `DROP VIEW' Syntax
* rename-table::                 `RENAME TABLE' Syntax
* truncate-table::               `TRUNCATE TABLE' Syntax


File: manual.info,  Node: alter-database,  Next: alter-function,  Prev: sql-syntax-data-definition,  Up: sql-syntax-data-definition

13.1.1 `ALTER DATABASE' Syntax
------------------------------

     ALTER {DATABASE | SCHEMA} [DB_NAME]
         ALTER_SPECIFICATION ...

     ALTER_SPECIFICATION:
         [DEFAULT] CHARACTER SET [=] CHARSET_NAME
       | [DEFAULT] COLLATE [=] COLLATION_NAME

*Note `ALTER DATABASE': alter-database. enables you to change the
overall characteristics of a database. These characteristics are stored
in the `db.opt' file in the database directory. To use *Note `ALTER
DATABASE': alter-database, you need the `ALTER' privilege on the
database.  *Note `ALTER SCHEMA': alter-database. is a synonym for *Note
`ALTER DATABASE': alter-database. as of MySQL 5.0.2.

The `CHARACTER SET' clause changes the default database character set.
The `COLLATE' clause changes the default database collation. *Note
charset::, discusses character set and collation names.

You can see what character sets and collations are available using,
respectively, the *Note `SHOW CHARACTER SET': show-character-set. and
*Note `SHOW COLLATION': show-collation.  statements. See *Note
show-character-set::, and *Note show-collation::, for more information.

If you change the default character set or collation for a database,
stored routines that use the database defaults must be dropped and
recreated so that they use the new defaults. (In a stored routine,
variables with character data types use the database defaults if the
character set or collation are not specified explicitly. See *Note
create-procedure::.)

The database name can be omitted, in which case the statement applies
to the default database.


File: manual.info,  Node: alter-function,  Next: alter-procedure,  Prev: alter-database,  Up: sql-syntax-data-definition

13.1.2 `ALTER FUNCTION' Syntax
------------------------------

     ALTER FUNCTION FUNC_NAME [CHARACTERISTIC ...]

     CHARACTERISTIC:
         { CONTAINS SQL | NO SQL | READS SQL DATA | MODIFIES SQL DATA }
       | SQL SECURITY { DEFINER | INVOKER }
       | COMMENT 'STRING'

This statement can be used to change the characteristics of a stored
function. More than one change may be specified in an *Note `ALTER
FUNCTION': alter-function. statement. However, you cannot change the
parameters or body of a stored function using this statement; to make
such changes, you must drop and re-create the function using *Note
`DROP FUNCTION': drop-function. and *Note `CREATE FUNCTION':
create-function.

As of MySQL 5.0.3, you must have the `ALTER ROUTINE' privilege for the
function. (That privilege is granted automatically to the function
creator.) If binary logging is enabled, the *Note `ALTER FUNCTION':
alter-function.  statement might also require the `SUPER' privilege, as
described in *Note stored-programs-logging::.


File: manual.info,  Node: alter-procedure,  Next: alter-table,  Prev: alter-function,  Up: sql-syntax-data-definition

13.1.3 `ALTER PROCEDURE' Syntax
-------------------------------

     ALTER PROCEDURE PROC_NAME [CHARACTERISTIC ...]

     CHARACTERISTIC:
         COMMENT 'STRING'
       | { CONTAINS SQL | NO SQL | READS SQL DATA | MODIFIES SQL DATA }
       | SQL SECURITY { DEFINER | INVOKER }

This statement can be used to change the characteristics of a stored
procedure. More than one change may be specified in an *Note `ALTER
PROCEDURE': alter-procedure. statement. However, you cannot change the
parameters or body of a stored procedure using this statement; to make
such changes, you must drop and re-create the procedure using *Note
`DROP PROCEDURE': drop-procedure. and *Note `CREATE PROCEDURE':
create-procedure.

As of MySQL 5.0.3, you must have the `ALTER ROUTINE' privilege for the
procedure. By default, that privilege is granted automatically to the
procedure creator. This behavior can be changed by disabling the
`automatic_sp_privileges' system variable. See *Note
stored-routines-privileges::.


File: manual.info,  Node: alter-table,  Next: alter-view,  Prev: alter-procedure,  Up: sql-syntax-data-definition

13.1.4 `ALTER TABLE' Syntax
---------------------------

* Menu:

* alter-table-examples::         `ALTER TABLE' Examples

     ALTER [IGNORE] TABLE TBL_NAME
         [ALTER_SPECIFICATION [, ALTER_SPECIFICATION] ...]

     ALTER_SPECIFICATION:
         TABLE_OPTIONS
       | ADD [COLUMN] COL_NAME COLUMN_DEFINITION
             [FIRST | AFTER COL_NAME ]
       | ADD [COLUMN] (COL_NAME COLUMN_DEFINITION,...)
       | ADD {INDEX|KEY} [INDEX_NAME]
             [INDEX_TYPE] (INDEX_COL_NAME,...) [INDEX_TYPE]
       | ADD [CONSTRAINT [SYMBOL]] PRIMARY KEY
             [INDEX_TYPE] (INDEX_COL_NAME,...) [INDEX_TYPE]
       | ADD [CONSTRAINT [SYMBOL]]
             UNIQUE [INDEX|KEY] [INDEX_NAME]
             [INDEX_TYPE] (INDEX_COL_NAME,...) [INDEX_TYPE]
       | ADD [FULLTEXT|SPATIAL] [INDEX|KEY] [INDEX_NAME]
             (INDEX_COL_NAME,...) [INDEX_TYPE]
       | ADD [CONSTRAINT [SYMBOL]]
             FOREIGN KEY [INDEX_NAME] (INDEX_COL_NAME,...)
             REFERENCE_DEFINITION
       | ALTER [COLUMN] COL_NAME {SET DEFAULT LITERAL | DROP DEFAULT}
       | CHANGE [COLUMN] OLD_COL_NAME NEW_COL_NAME COLUMN_DEFINITION
             [FIRST|AFTER COL_NAME]
       | MODIFY [COLUMN] COL_NAME COLUMN_DEFINITION
             [FIRST | AFTER COL_NAME]
       | DROP [COLUMN] COL_NAME
       | DROP PRIMARY KEY
       | DROP {INDEX|KEY} INDEX_NAME
       | DROP FOREIGN KEY FK_SYMBOL
       | DISABLE KEYS
       | ENABLE KEYS
       | RENAME [TO] NEW_TBL_NAME
       | ORDER BY COL_NAME [, COL_NAME] ...
       | CONVERT TO CHARACTER SET CHARSET_NAME [COLLATE COLLATION_NAME]
       | [DEFAULT] CHARACTER SET [=] CHARSET_NAME [COLLATE [=] COLLATION_NAME]
       | DISCARD TABLESPACE
       | IMPORT TABLESPACE

     INDEX_COL_NAME:
         COL_NAME [(LENGTH)] [ASC | DESC]

     INDEX_TYPE:
         USING {BTREE | HASH}

     TABLE_OPTIONS:
         TABLE_OPTION [[,] TABLE_OPTION] ...  (see *Note `CREATE TABLE': create-table. options)

*Note `ALTER TABLE': alter-table. changes the structure of a table. For
example, you can add or delete columns, create or destroy indexes,
change the type of existing columns, or rename columns or the table
itself. You can also change characteristics such as the storage engine
used for the table or the table comment.

Following the table name, specify the alterations to be made. If none
are given, *Note `ALTER TABLE': alter-table. does nothing.

The syntax for many of the permissible alterations is similar to
clauses of the *Note `CREATE TABLE': create-table.  statement. See
*Note create-table::, for more information.

Some operations may result in warnings if attempted on a table for
which the storage engine does not support the operation. These warnings
can be displayed with *Note `SHOW WARNINGS': show-warnings. See *Note
show-warnings::.

If you use *Note `ALTER TABLE': alter-table. to change a column
specification but `DESCRIBE TBL_NAME' indicates that your column was
not changed, it is possible that MySQL ignored your modification for
one of the reasons described in *Note silent-column-changes::.

For information on troubleshooting *Note `ALTER TABLE': alter-table,
see *Note alter-table-problems::.

In most cases, *Note `ALTER TABLE': alter-table. makes a temporary copy
of the original table. MySQL waits for other operations that are
modifying the table, then proceeds. It incorporates the alteration into
the copy, deletes the original table, and renames the new one. While
*Note `ALTER TABLE': alter-table. is executing, the original table is
readable by other sessions. Updates and writes to the table that begin
after the *Note `ALTER TABLE': alter-table. operation begins are
stalled until the new table is ready, then are automatically redirected
to the new table without any failed updates. The temporary table is
created in the database directory of the new table. This can differ
from the database directory of the original table for *Note `ALTER
TABLE': alter-table. operations that rename the table to a different
database.

If you use `ALTER TABLE TBL_NAME RENAME TO NEW_TBL_NAME' without any
other options, MySQL simply renames any files that correspond to the
table TBL_NAME without making a copy. (You can also use the *Note
`RENAME TABLE': rename-table. statement to rename tables. See *Note
rename-table::.) Any privileges granted specifically for the renamed
table are not migrated to the new name. They must be changed manually.

If you use any option to *Note `ALTER TABLE': alter-table. other than
`RENAME', MySQL always creates a temporary table, even if the data
wouldn't strictly need to be copied (such as when you change the name
of a column). For `MyISAM' tables, you can speed up index re-creation
(the slowest part of the alteration process) by setting the
`myisam_sort_buffer_size' system variable to a high value.

   * To use *Note `ALTER TABLE': alter-table, you need `ALTER',
     `CREATE', and `INSERT' privileges for the table. Renaming a table
     requires `ALTER' and `DROP' on the old table, `ALTER', `CREATE',
     and `INSERT' on the new table.

   * `IGNORE' is a MySQL extension to standard SQL. It controls how
     *Note `ALTER TABLE': alter-table. works if there are duplicates on
     unique keys in the new table or if warnings occur when strict mode
     is enabled. If `IGNORE' is not specified, the copy is aborted and
     rolled back if duplicate-key errors occur.  If `IGNORE' is
     specified, only the first row is used of rows with duplicates on a
     unique key. The other conflicting rows are deleted. Incorrect
     values are truncated to the closest matching acceptable value.

   * Pending *Note `INSERT DELAYED': insert-delayed.  statements are
     lost if a table is write locked and *Note `ALTER TABLE':
     alter-table. is used to modify the table structure.

   * TABLE_OPTION signifies a table option of the kind that can be used
     in the *Note `CREATE TABLE': create-table. statement, such as
     `ENGINE', `AUTO_INCREMENT', or `AVG_ROW_LENGTH'.  (*Note
     create-table::, lists all table options.)  However, *Note `ALTER
     TABLE': alter-table. ignores the `DATA DIRECTORY' and `INDEX
     DIRECTORY' table options.

     For example, to convert a table to be an `InnoDB' table, use this
     statement:

          ALTER TABLE t1 ENGINE = InnoDB;

     When you specify an `ENGINE' clause, *Note `ALTER TABLE':
     alter-table. rebuilds the table.  This is true even if the table
     already has the specified storage engine.

     The outcome of attempting to change a table's storage engine is
     affected by whether the desired storage engine is available and
     the setting of the `NO_ENGINE_SUBSTITUTION' SQL mode, as described
     in *Note server-sql-mode::.

     As of MySQL 5.0.23, to prevent inadvertent loss of data, *Note
     `ALTER TABLE': alter-table. cannot be used to change the storage
     engine of a table to `MERGE' or `BLACKHOLE'.

     To change the value of the `AUTO_INCREMENT' counter to be used for
     new rows, do this:

          ALTER TABLE t2 AUTO_INCREMENT = VALUE;

     You cannot reset the counter to a value less than or equal to any
     that have already been used. For `MyISAM', if the value is less
     than or equal to the maximum value currently in the
     `AUTO_INCREMENT' column, the value is reset to the current maximum
     plus one. For `InnoDB', you can use `ALTER TABLE ...
     AUTO_INCREMENT = VALUE' as of MySQL 5.0.3, but _if the value is
     less than the current maximum value in the column, no error occurs
     and the current sequence value is not changed._

   * You can issue multiple `ADD', `ALTER', `DROP', and `CHANGE'
     clauses in a single *Note `ALTER TABLE': alter-table. statement,
     separated by commas. This is a MySQL extension to standard SQL,
     which permits only one of each clause per *Note `ALTER TABLE':
     alter-table. statement. For example, to drop multiple columns in a
     single statement, do this:

          ALTER TABLE t2 DROP COLUMN c, DROP COLUMN d;

   * `CHANGE COL_NAME', `DROP COL_NAME', and `DROP INDEX' are MySQL
     extensions to standard SQL.

   * The word `COLUMN' is optional and can be omitted.

   * COLUMN_DEFINITION clauses use the same syntax for `ADD' and
     `CHANGE' as for *Note `CREATE TABLE': create-table. See *Note
     create-table::.

   * You can rename a column using a `CHANGE OLD_COL_NAME NEW_COL_NAME
     COLUMN_DEFINITION' clause.  To do so, specify the old and new
     column names and the definition that the column currently has. For
     example, to rename an *Note `INTEGER': numeric-types. column from
     `a' to `b', you can do this:

          ALTER TABLE t1 CHANGE a b INTEGER;

     If you want to change a column's type but not the name, `CHANGE'
     syntax still requires an old and new column name, even if they are
     the same. For example:

          ALTER TABLE t1 CHANGE b b BIGINT NOT NULL;

     You can also use `MODIFY' to change a column's type without
     renaming it:

          ALTER TABLE t1 MODIFY b BIGINT NOT NULL;

     `MODIFY' is an extension to *Note `ALTER TABLE': alter-table. for
     Oracle compatibility.

     When you use `CHANGE' or `MODIFY', COLUMN_DEFINITION must include
     the data type and all attributes that should apply to the new
     column, other than index attributes such as `PRIMARY KEY' or
     `UNIQUE'. Attributes present in the original definition but not
     specified for the new definition are not carried forward. Suppose
     that a column `col1' is defined as `INT UNSIGNED DEFAULT 1 COMMENT
     'my column'' and you modify the column as follows:

          ALTER TABLE t1 MODIFY col1 BIGINT;

     The resulting column will be defined as `BIGINT', but will not
     include the attributes `UNSIGNED DEFAULT 1 COMMENT 'my column''. To
     retain them, the statement should be:

          ALTER TABLE t1 MODIFY col1 BIGINT UNSIGNED DEFAULT 1 COMMENT 'my column';

   * When you change a data type using `CHANGE' or `MODIFY', MySQL
     tries to convert existing column values to the new type as well as
     possible.

     *Warning*:

     This conversion may result in alteration of data. For example, if
     you shorten a string column, values may be truncated. To prevent
     the operation from succeeding if conversions to the new data type
     would result in loss of data, enable strict SQL mode before using
     *Note `ALTER TABLE': alter-table. (see *Note server-sql-mode::).

   * To add a column at a specific position within a table row, use
     `FIRST' or `AFTER COL_NAME'. The default is to add the column
     last. You can also use `FIRST' and `AFTER' in `CHANGE' or `MODIFY'
     operations to reorder columns within a table.

   * `ALTER ... SET DEFAULT' or `ALTER ...  DROP DEFAULT' specify a new
     default value for a column or remove the old default value,
     respectively. If the old default is removed and the column can be
     `NULL', the new default is `NULL'. If the column cannot be `NULL',
     MySQL assigns a default value as described in *Note
     data-type-defaults::.

   * *Note `DROP INDEX': drop-index. removes an index.  This is a MySQL
     extension to standard SQL. See *Note drop-index::. If you are
     unsure of the index name, use `SHOW INDEX FROM TBL_NAME'.

   * If columns are dropped from a table, the columns are also removed
     from any index of which they are a part. If all columns that make
     up an index are dropped, the index is dropped as well. If you use
     `CHANGE' or `MODIFY' to shorten a column for which an index exists
     on the column, and the resulting column length is less than the
     index length, MySQL shortens the index automatically.

   * If a table contains only one column, the column cannot be dropped.
     If what you intend is to remove the table, use *Note `DROP TABLE':
     drop-table. instead.

   * `DROP PRIMARY KEY' drops the primary key. If there is no primary
     key, an error occurs.

     If you add a `UNIQUE INDEX' or `PRIMARY KEY' to a table, MySQL
     stores it before any nonunique index to permit detection of
     duplicate keys as early as possible.

   * Some storage engines permit you to specify an index type when
     creating an index. The syntax for the INDEX_TYPE specifier is
     `USING TYPE_NAME'.  For details about `USING', see *Note
     create-index::. Before MySQL 5.0.60, `USING' can be given only
     before the index column list. As of 5.0.60, the preferred position
     is after the column list. Support for use of the option before the
     column list will be removed in a future MySQL release.

     INDEX_OPTION values specify additional options for an index.
     `USING' is one such option. For details about permissible
     INDEX_OPTION values, see *Note create-index::.

   * After an *Note `ALTER TABLE': alter-table. statement, it may be
     necessary to run *Note `ANALYZE TABLE': analyze-table. to update
     index cardinality information. See *Note show-index::.

   * `ORDER BY' enables you to create the new table with the rows in a
     specific order. Note that the table does not remain in this order
     after inserts and deletes. This option is useful primarily when
     you know that you are mostly to query the rows in a certain order
     most of the time. By using this option after major changes to the
     table, you might be able to get higher performance. In some cases,
     it might make sorting easier for MySQL if the table is in order by
     the column that you want to order it by later.

     `ORDER BY' syntax permits one or more column names to be specified
     for sorting, each of which optionally can be followed by `ASC' or
     `DESC' to indicate ascending or descending sort order,
     respectively. The default is ascending order. Only column names
     are permitted as sort criteria; arbitrary expressions are not
     permitted. This clause should be given last after any other
     clauses.

     `ORDER BY' does not make sense for `InnoDB' tables that contain a
     user-defined clustered index (`PRIMARY KEY' or `NOT NULL UNIQUE'
     index).  `InnoDB' always orders table rows according to such an
     index if one is present. The same is true for `BDB' tables that
     contain a user-defined `PRIMARY KEY'.

   * If you use *Note `ALTER TABLE': alter-table. on a `MyISAM' table,
     all nonunique indexes are created in a separate batch (as for
     *Note `REPAIR TABLE': repair-table.). This should make *Note
     `ALTER TABLE': alter-table. much faster when you have many indexes.

     This feature can be activated explicitly for a `MyISAM' table.
     `ALTER TABLE ...  DISABLE KEYS' tells MySQL to stop updating
     nonunique indexes. `ALTER TABLE ... ENABLE KEYS' then should be
     used to re-create missing indexes. MySQL does this with a special
     algorithm that is much faster than inserting keys one by one, so
     disabling keys before performing bulk insert operations should
     give a considerable speedup. Using `ALTER TABLE ... DISABLE KEYS'
     requires the `INDEX' privilege in addition to the privileges
     mentioned earlier.

     While the nonunique indexes are disabled, they are ignored for
     statements such as *Note `SELECT': select. and *Note `EXPLAIN':
     explain. that otherwise would use them.

   * If *Note `ALTER TABLE': alter-table. for an `InnoDB' table results
     in changes to column values (for example, because a column is
     truncated), `InnoDB''s `FOREIGN KEY' constraint checks do not
     notice possible violations caused by changing the values.

   * The `FOREIGN KEY' and `REFERENCES' clauses are supported by the
     `InnoDB' storage engine, which implements `ADD [CONSTRAINT
     [SYMBOL]] FOREIGN KEY (...) REFERENCES ... (...)'. See *Note
     innodb-foreign-key-constraints::. For other storage engines, the
     clauses are parsed but ignored. The `CHECK' clause is parsed but
     ignored by all storage engines. See *Note create-table::. The
     reason for accepting but ignoring syntax clauses is for
     compatibility, to make it easier to port code from other SQL
     servers, and to run applications that create tables with
     references. See *Note differences-from-ansi::.

     *Important*:

     The inline `REFERENCES' specifications where the references are
     defined as part of the column specification are silently ignored by
     `InnoDB'. InnoDB only accepts `REFERENCES' clauses defined as part
     of a separate `FOREIGN KEY' specification.

   * `InnoDB' supports the use of *Note `ALTER TABLE': alter-table. to
     drop foreign keys:

          ALTER TABLE TBL_NAME DROP FOREIGN KEY FK_SYMBOL;

     For more information, see *Note innodb-foreign-key-constraints::.

   * You cannot add a foreign key and drop a foreign key in separate
     clauses of a single *Note `ALTER TABLE': alter-table. statement.
     You must use separate statements.

   * For an `InnoDB' table that is created with its own tablespace in
     an `.ibd' file, that file can be discarded and imported. To
     discard the `.ibd' file, use this statement:

          ALTER TABLE TBL_NAME DISCARD TABLESPACE;

     This deletes the current `.ibd' file, so be sure that you have a
     backup first. Attempting to access the table while the tablespace
     file is discarded results in an error.

     To import the backup `.ibd' file back into the table, copy it into
     the database directory, and then issue this statement:

          ALTER TABLE TBL_NAME IMPORT TABLESPACE;

     The tablespace file must have been created on the server into
     which it is imported later.

     See *Note innodb-multiple-tablespaces::.

   * If you want to change the table default character set and all
     character columns (*Note `CHAR': char, *Note `VARCHAR': char,
     *Note `TEXT': blob.) to a new character set, use a statement like
     this:

          ALTER TABLE TBL_NAME CONVERT TO CHARACTER SET CHARSET_NAME;

     For a column that has a data type of *Note `VARCHAR': char. or one
     of the *Note `TEXT': blob. types, `CONVERT TO CHARACTER SET' will
     change the data type as necessary to ensure that the new column is
     long enough to store as many characters as the original column.
     For example, a *Note `TEXT': blob. column has two length bytes,
     which store the byte-length of values in the column, up to a
     maximum of 65,535. For a `latin1' *Note `TEXT': blob. column, each
     character requires a single byte, so the column can store up to
     65,535 characters. If the column is converted to `utf8', each
     character might require up to 3 bytes, for a maximum possible
     length of 3 x 65,535 = 196,605 bytes. That length will not fit in a
     *Note `TEXT': blob. column's length bytes, so MySQL will convert
     the data type to *Note `MEDIUMTEXT': blob, which is the smallest
     string type for which the length bytes can record a value of
     196,605. Similarly, a *Note `VARCHAR': char. column might be
     converted to *Note `MEDIUMTEXT': blob.

     To avoid data type changes of the type just described, do not use
     `CONVERT TO CHARACTER SET'. Instead, use `MODIFY' to change
     individual columns. For example:

          ALTER TABLE t MODIFY latin1_text_col TEXT CHARACTER SET utf8;
          ALTER TABLE t MODIFY latin1_varchar_col VARCHAR(M) CHARACTER SET utf8;

     If you specify `CONVERT TO CHARACTER SET binary', the *Note
     `CHAR': char, *Note `VARCHAR': char, and *Note `TEXT': blob.
     columns are converted to their corresponding binary string types
     (*Note `BINARY': binary-varbinary, *Note `VARBINARY':
     binary-varbinary, *Note `BLOB': blob.). This means that the
     columns no longer will have a character set and a subsequent
     `CONVERT TO' operation will not apply to them.

     If CHARSET_NAME is `DEFAULT', the database character set is used.

     *Warning*:

     The `CONVERT TO' operation converts column values between the
     character sets. This is _not_ what you want if you have a column
     in one character set (like `latin1') but the stored values
     actually use some other, incompatible character set (like `utf8').
     In this case, you have to do the following for each such column:

          ALTER TABLE t1 CHANGE c1 c1 BLOB;
          ALTER TABLE t1 CHANGE c1 c1 TEXT CHARACTER SET utf8;

     The reason this works is that there is no conversion when you
     convert to or from *Note `BLOB': blob.  columns.

     To change only the _default_ character set for a table, use this
     statement:

          ALTER TABLE TBL_NAME DEFAULT CHARACTER SET CHARSET_NAME;

     The word `DEFAULT' is optional. The default character set is the
     character set that is used if you do not specify the character set
     for columns that you add to a table later (for example, with
     `ALTER TABLE ... ADD column').

With the *Note `mysql_info()': mysql-info. C API function, you can find
out how many rows were copied by *Note `ALTER TABLE': alter-table, and
(when `IGNORE' is used) how many rows were deleted due to duplication
of unique key values. See *Note mysql-info::.


File: manual.info,  Node: alter-table-examples,  Prev: alter-table,  Up: alter-table

13.1.4.1 `ALTER TABLE' Examples
...............................

Begin with a table `t1' that is created as shown here:

     CREATE TABLE t1 (a INTEGER,b CHAR(10));

To rename the table from `t1' to `t2':

     ALTER TABLE t1 RENAME t2;

To change column `a' from *Note `INTEGER': numeric-types. to `TINYINT
NOT NULL' (leaving the name the same), and to change column `b' from
`CHAR(10)' to `CHAR(20)' as well as renaming it from `b' to `c':

     ALTER TABLE t2 MODIFY a TINYINT NOT NULL, CHANGE b c CHAR(20);

To add a new *Note `TIMESTAMP': datetime. column named `d':

     ALTER TABLE t2 ADD d TIMESTAMP;

To add an index on column `d' and a `UNIQUE' index on column `a':

     ALTER TABLE t2 ADD INDEX (d), ADD UNIQUE (a);

To remove column `c':

     ALTER TABLE t2 DROP COLUMN c;

To add a new `AUTO_INCREMENT' integer column named `c':

     ALTER TABLE t2 ADD c INT UNSIGNED NOT NULL AUTO_INCREMENT,
       ADD PRIMARY KEY (c);

Note that we indexed `c' (as a `PRIMARY KEY') because `AUTO_INCREMENT'
columns must be indexed, and also that we declare `c' as `NOT NULL'
because primary key columns cannot be `NULL'.

When you add an `AUTO_INCREMENT' column, column values are filled in
with sequence numbers automatically. For `MyISAM' tables, you can set
the first sequence number by executing `SET INSERT_ID=VALUE' before
*Note `ALTER TABLE': alter-table. or by using the `AUTO_INCREMENT=VALUE'
table option. See *Note server-system-variables::.

With `MyISAM' tables, if you do not change the `AUTO_INCREMENT' column,
the sequence number is not affected. If you drop an `AUTO_INCREMENT'
column and then add another `AUTO_INCREMENT' column, the numbers are
resequenced beginning with 1.

When replication is used, adding an `AUTO_INCREMENT' column to a table
might not produce the same ordering of the rows on the slave and the
master. This occurs because the order in which the rows are numbered
depends on the specific storage engine used for the table and the order
in which the rows were inserted. If it is important to have the same
order on the master and slave, the rows must be ordered before
assigning an `AUTO_INCREMENT' number. Assuming that you want to add an
`AUTO_INCREMENT' column to the table `t1', the following statements
produce a new table `t2' identical to `t1' but with an `AUTO_INCREMENT'
column:

     CREATE TABLE t2 (id INT AUTO_INCREMENT PRIMARY KEY)
     SELECT * FROM t1 ORDER BY col1, col2;

This assumes that the table `t1' has columns `col1' and `col2'.

This set of statements will also produce a new table `t2' identical to
`t1', with the addition of an `AUTO_INCREMENT' column:

     CREATE TABLE t2 LIKE t1;
     ALTER TABLE t2 ADD id INT AUTO_INCREMENT PRIMARY KEY;
     INSERT INTO t2 SELECT * FROM t1 ORDER BY col1, col2;

*Important*:

To guarantee the same ordering on both master and slave, _all_ columns
of `t1' must be referenced in the `ORDER BY' clause.

Regardless of the method used to create and populate the copy having
the `AUTO_INCREMENT' column, the final step is to drop the original
table and then rename the copy:

     DROP t1;
     ALTER TABLE t2 RENAME t1;


File: manual.info,  Node: alter-view,  Next: create-database,  Prev: alter-table,  Up: sql-syntax-data-definition

13.1.5 `ALTER VIEW' Syntax
--------------------------

     ALTER
         [ALGORITHM = {UNDEFINED | MERGE | TEMPTABLE}]
         [DEFINER = { USER | CURRENT_USER }]
         [SQL SECURITY { DEFINER | INVOKER }]
         VIEW VIEW_NAME [(COLUMN_LIST)]
         AS SELECT_STATEMENT
         [WITH [CASCADED | LOCAL] CHECK OPTION]

This statement changes the definition of a view, which must exist.  The
syntax is similar to that for *Note `CREATE VIEW': create-view. and the
effect is the same as for *Note `CREATE OR REPLACE VIEW': create-view.
See *Note create-view::. This statement requires the `CREATE VIEW' and
`DROP' privileges for the view, and some privilege for each column
referred to in the *Note `SELECT': select. statement. As of MySQL
5.0.52, *Note `ALTER VIEW': alter-view. is permitted only to the
original definer or users with the `SUPER' privilege.

This statement was added in MySQL 5.0.1. The `DEFINER' and `SQL
SECURITY' clauses may be used as of MySQL 5.0.16 to specify the security
context to be used when checking access privileges at view invocation
time. For details, see *Note create-view::.


File: manual.info,  Node: create-database,  Next: create-function,  Prev: alter-view,  Up: sql-syntax-data-definition

13.1.6 `CREATE DATABASE' Syntax
-------------------------------

     CREATE {DATABASE | SCHEMA} [IF NOT EXISTS] DB_NAME
         [CREATE_SPECIFICATION] ...

     CREATE_SPECIFICATION:
         [DEFAULT] CHARACTER SET [=] CHARSET_NAME
       | [DEFAULT] COLLATE [=] COLLATION_NAME

*Note `CREATE DATABASE': create-database. creates a database with the
given name. To use this statement, you need the `CREATE' privilege for
the database.  *Note `CREATE SCHEMA': create-database. is a synonym for
*Note `CREATE DATABASE': create-database. as of MySQL 5.0.2.

An error occurs if the database exists and you did not specify `IF NOT
EXISTS'.

CREATE_SPECIFICATION options specify database characteristics. Database
characteristics are stored in the `db.opt' file in the database
directory.  The `CHARACTER SET' clause specifies the default database
character set. The `COLLATE' clause specifies the default database
collation.  *Note charset::, discusses character set and collation
names.

A database in MySQL is implemented as a directory containing files that
correspond to tables in the database. Because there are no tables in a
database when it is initially created, the *Note `CREATE DATABASE':
create-database. statement creates only a directory under the MySQL
data directory and the `db.opt' file. Rules for permissible database
names are given in *Note identifiers::.

If you manually create a directory under the data directory (for
example, with `mkdir'), the server considers it a database directory
and it shows up in the output of *Note `SHOW DATABASES': show-databases.

You can also use the *Note `mysqladmin': mysqladmin. program to create
databases. See *Note mysqladmin::.


File: manual.info,  Node: create-function,  Next: create-index,  Prev: create-database,  Up: sql-syntax-data-definition

13.1.7 The `CREATE FUNCTION' Statement
--------------------------------------

The *Note `CREATE FUNCTION': create-function. statement is used to
create stored functions and user-defined functions (UDFs):

   * For information about creating stored functions, see *Note
     create-procedure::.

   * For information about creating user-defined functions, see *Note
     create-function-udf::.


File: manual.info,  Node: create-index,  Next: create-procedure,  Prev: create-function,  Up: sql-syntax-data-definition

13.1.8 `CREATE INDEX' Syntax
----------------------------

     CREATE [UNIQUE|FULLTEXT|SPATIAL] INDEX INDEX_NAME
         [INDEX_TYPE]
         ON TBL_NAME (INDEX_COL_NAME,...)
         [INDEX_TYPE]

     INDEX_COL_NAME:
         COL_NAME [(LENGTH)] [ASC | DESC]

     INDEX_TYPE:
         USING {BTREE | HASH}

*Note `CREATE INDEX': create-index. is mapped to an *Note `ALTER
TABLE': alter-table. statement to create indexes. See *Note
alter-table::.  *Note `CREATE INDEX': create-index. cannot be used to
create a `PRIMARY KEY'; use *Note `ALTER TABLE': alter-table. instead.
For more information about indexes, see *Note mysql-indexes::.

Normally, you create all indexes on a table at the time the table
itself is created with *Note `CREATE TABLE': create-table. See *Note
create-table::.  *Note `CREATE INDEX': create-index. enables you to add
indexes to existing tables.

A column list of the form `(col1,col2,...)' creates a multiple-column
index. Index values are formed by concatenating the values of the given
columns.

Indexes can be created that use only the leading part of column values,
using `COL_NAME(LENGTH)' syntax to specify an index prefix length:

   * Prefixes can be specified for *Note `CHAR': char, *Note `VARCHAR':
     char, *Note `BINARY': binary-varbinary, and *Note `VARBINARY':
     binary-varbinary. columns.

   * *Note `BLOB': blob. and *Note `TEXT': blob. columns also can be
     indexed, but a prefix length _must_ be given.

   * Prefix lengths are given in characters for nonbinary string types
     and in bytes for binary string types. That is, index entries
     consist of the first LENGTH characters of each column value for
     *Note `CHAR': char, *Note `VARCHAR': char, and *Note `TEXT': blob.
     columns, and the first LENGTH bytes of each column value for *Note
     `BINARY': binary-varbinary, *Note `VARBINARY': binary-varbinary,
     and *Note `BLOB': blob. columns.

   * For spatial columns, prefix values can be given as described later
     in this section.

The statement shown here creates an index using the first 10 characters
of the `name' column:

     CREATE INDEX part_of_name ON customer (name(10));

If names in the column usually differ in the first 10 characters, this
index should not be much slower than an index created from the entire
`name' column. Also, using column prefixes for indexes can make the
index file much smaller, which could save a lot of disk space and might
also speed up *Note `INSERT': insert. operations.

Prefix support and lengths of prefixes (where supported) are storage
engine dependent. For example, a prefix can be up to 1000 bytes long
for `MyISAM' tables, and 767 bytes for `InnoDB' tables. The
`NDBCLUSTER' storage engine does not support prefixes (see *Note
mysql-cluster-limitations-unsupported::).

*Note*:

Prefix limits are measured in bytes, whereas the prefix length in *Note
`CREATE INDEX': create-index. statements is interpreted as number of
characters for nonbinary data types (*Note `CHAR': char, *Note
`VARCHAR': char, *Note `TEXT': blob.). Take this into account when
specifying a prefix length for a column that uses a multi-byte
character set.

A `UNIQUE' index creates a constraint such that all values in the index
must be distinct. An error occurs if you try to add a new row with a
key value that matches an existing row. This constraint does not apply
to `NULL' values except for the `BDB' storage engine. For other
engines, a `UNIQUE' index permits multiple `NULL' values for columns
that can contain `NULL'. If you specify a prefix value for a column in
a `UNIQUE' index, the column values must be unique within the prefix.

`FULLTEXT' indexes are supported only for `MyISAM' tables and can
include only *Note `CHAR': char, *Note `VARCHAR': char, and *Note
`TEXT': blob. columns. Indexing always happens over the entire column;
column prefix indexing is not supported and any prefix length is
ignored if specified. See *Note fulltext-search::, for details of
operation.

The `MyISAM', `InnoDB', *Note `NDB': mysql-cluster, `BDB', and
`ARCHIVE' storage engines support spatial columns such as (`POINT' and
`GEOMETRY'.  (*Note spatial-extensions::, describes the spatial data
types.) However, support for spatial column indexing varies among
engines. Spatial and nonspatial indexes are available according to the
following rules.

Spatial indexes (created using `SPATIAL INDEX') have these
characteristics:

   * Available only for `MyISAM' tables.  Specifying `SPATIAL INDEX'
     for other storage engines results in an error.

   * Indexed columns must be `NOT NULL'.

   * In MySQL 5.0, the full width of each column is indexed by default,
     but column prefix lengths are permitted.  However, as of MySQL
     5.0.40, the length is not displayed in *Note `SHOW CREATE TABLE':
     show-create-table. output.  *Note `mysqldump': mysqldump. uses
     that statement. As of that version, if a table with `SPATIAL'
     indexes containing prefixed columns is dumped and reloaded, the
     index is created with no prefixes. (The full column width of each
     column is indexed.)

Characteristics of nonspatial indexes (created with `INDEX', `UNIQUE',
or `PRIMARY KEY'):

   * Permitted for any storage engine that supports spatial columns
     except `ARCHIVE'.

   * Columns can be `NULL' unless the index is a primary key.

   * For each spatial column in a non-`SPATIAL' index except `POINT'
     columns, a column prefix length must be specified. (This is the
     same requirement as for indexed *Note `BLOB': blob. columns.) The
     prefix length is given in bytes.

   * The index type for a non-`SPATIAL' index depends on the storage
     engine. Currently, B-tree is used.

In MySQL 5.0:

   * You can add an index on a column that can have `NULL' values only
     if you are using the `MyISAM', `InnoDB', `BDB', or `MEMORY' storage
     engine.

   * You can add an index on a *Note `BLOB': blob.  or *Note `TEXT':
     blob. column only if you are using the `MyISAM', `BDB', or
     `InnoDB' storage engine.

An INDEX_COL_NAME specification can end with `ASC' or `DESC'. These
keywords are permitted for future extensions for specifying ascending
or descending index value storage. Currently, they are parsed but
ignored; index values are always stored in ascending order.

Some storage engines permit you to specify an index type when creating
an index. The permissible index type values supported by different
storage engines are shown in the following table. Where multiple index
types are listed, the first one is the default when no index type
specifier is given.

Storage Engine Permissible Index Types
`MyISAM'       `BTREE'
`InnoDB'       `BTREE'
`MEMORY'/`HEAP'`HASH', `BTREE'
*Note `NDB':   `HASH', `BTREE' (see note in text)
mysql-cluster. 

Example:

     CREATE TABLE lookup (id INT) ENGINE = MEMORY;
     CREATE INDEX id_index ON lookup (id) USING BTREE;

`BTREE' indexes are implemented by the *Note `NDBCLUSTER':
mysql-cluster. storage engine as T-tree indexes.

*Note*:

For indexes on *Note `NDB': mysql-cluster. table columns, the `USING'
option can be specified only for a unique index or primary key. `USING
HASH' prevents the creation of an implicit ordered index; otherwise,
creating a unique index or primary key on an *Note `NDB':
mysql-cluster. table automatically results in the creation of both an
ordered index and a hash index, each of which indexes the same set of
columns.

This means that a query using a unique index or primary key on a `NULL'
column is always handled by *Note `NDB': mysql-cluster. with a full
scan of the table.  In particular, if you plan to use an `IS NULL' or
`IS NOT NULL' condition involving a unique index or primary key column
of an *Note `NDB': mysql-cluster. table, you should create any such
index without `USING HASH'.

The INDEX_TYPE clause cannot be used together with `SPATIAL INDEX'.

If you specify an index type that is not legal for a given storage
engine, but there is another index type available that the engine can
use without affecting query results, the engine uses the available
type. The parser recognizes `RTREE' as a type name, but currently this
cannot be specified for any storage engine.

Before MySQL 5.0.60, this option can be given only before the `ON
TBL_NAME' clause.  Use of the option in this position is deprecated as
of 5.0.60 and support for it there will be removed in a future MySQL
release. If an INDEX_TYPE option is given in both the earlier and later
positions, the final option applies.

`TYPE TYPE_NAME' is recognized as a synonym for `USING TYPE_NAME'.
However, `USING' is the preferred form.


File: manual.info,  Node: create-procedure,  Next: create-table,  Prev: create-index,  Up: sql-syntax-data-definition

13.1.9 `CREATE PROCEDURE' and `CREATE FUNCTION' Syntax
------------------------------------------------------

     CREATE
         [DEFINER = { USER | CURRENT_USER }]
         PROCEDURE SP_NAME ([PROC_PARAMETER[,...]])
         [CHARACTERISTIC ...] ROUTINE_BODY

     CREATE
         [DEFINER = { USER | CURRENT_USER }]
         FUNCTION SP_NAME ([FUNC_PARAMETER[,...]])
         RETURNS TYPE
         [CHARACTERISTIC ...] ROUTINE_BODY

     PROC_PARAMETER:
         [ IN | OUT | INOUT ] PARAM_NAME TYPE

     FUNC_PARAMETER:
         PARAM_NAME TYPE

     TYPE:
         ANY VALID MYSQL DATA TYPE

     CHARACTERISTIC:
         COMMENT 'STRING'
       | LANGUAGE SQL
       | [NOT] DETERMINISTIC
       | { CONTAINS SQL | NO SQL | READS SQL DATA | MODIFIES SQL DATA }
       | SQL SECURITY { DEFINER | INVOKER }

     ROUTINE_BODY:
         VALID SQL ROUTINE STATEMENT

These statements create stored routines. By default, a routine is
associated with the default database. To associate the routine
explicitly with a given database, specify the name as DB_NAME.SP_NAME
when you create it.

The *Note `CREATE FUNCTION': create-function. statement is also used in
MySQL to support UDFs (user-defined functions). See *Note
adding-functions::. A UDF can be regarded as an external stored
function. Stored functions share their namespace with UDFs. See *Note
function-resolution::, for the rules describing how the server
interprets references to different kinds of functions.

To invoke a stored procedure, use the *Note `CALL': call. statement (see
*Note call::). To invoke a stored function, refer to it in an
expression. The function returns a value during expression evaluation.

As of MySQL 5.0.3, *Note `CREATE PROCEDURE': create-procedure.  and
*Note `CREATE FUNCTION': create-function. require the `CREATE ROUTINE'
privilege. They might also require the `SUPER' privilege, depending on
the `DEFINER' value, as described later in this section. If binary
logging is enabled, *Note `CREATE FUNCTION': create-function. might
require the `SUPER' privilege, as described in *Note
stored-programs-logging::.

By default, MySQL automatically grants the `ALTER ROUTINE' and
`EXECUTE' privileges to the routine creator. This behavior can be
changed by disabling the `automatic_sp_privileges' system variable. See
*Note stored-routines-privileges::.

The `DEFINER' and `SQL SECURITY' clauses specify the security context
to be used when checking access privileges at routine execution time,
as described later in this section.

If the routine name is the same as the name of a built-in SQL function,
a syntax error occurs unless you use a space between the name and the
following parenthesis when defining the routine or invoking it later.
For this reason, avoid using the names of existing SQL functions for
your own stored routines.

The `IGNORE_SPACE' SQL mode applies to built-in functions, not to
stored routines. It is always permissible to have spaces after a stored
routine name, regardless of whether `IGNORE_SPACE' is enabled.

The parameter list enclosed within parentheses must always be present.
If there are no parameters, an empty parameter list of `()' should be
used. Parameter names are not case sensitive.

Each parameter is an `IN' parameter by default.  To specify otherwise
for a parameter, use the keyword `OUT' or `INOUT' before the parameter
name.

*Note*:

Specifying a parameter as `IN', `OUT', or `INOUT' is valid only for a
`PROCEDURE'. For a `FUNCTION', parameters are always regarded as `IN'
parameters.

An `IN' parameter passes a value into a procedure. The procedure might
modify the value, but the modification is not visible to the caller
when the procedure returns. An `OUT' parameter passes a value from the
procedure back to the caller. Its initial value is `NULL' within the
procedure, and its value is visible to the caller when the procedure
returns. An `INOUT' parameter is initialized by the caller, can be
modified by the procedure, and any change made by the procedure is
visible to the caller when the procedure returns.

For each `OUT' or `INOUT' parameter, pass a user-defined variable in the
*Note `CALL': call. statement that invokes the procedure so that you
can obtain its value when the procedure returns. If you are calling the
procedure from within another stored procedure or function, you can
also pass a routine parameter or local routine variable as an `IN' or
`INOUT' parameter.

The following example shows a simple stored procedure that uses an
`OUT' parameter:

     mysql> delimiter //

     mysql> CREATE PROCEDURE simpleproc (OUT param1 INT)
         -> BEGIN
         ->   SELECT COUNT(*) INTO param1 FROM t;
         -> END//
     Query OK, 0 rows affected (0.00 sec)

     mysql> delimiter ;

     mysql> CALL simpleproc(@a);
     Query OK, 0 rows affected (0.00 sec)

     mysql> SELECT @a;
     +------+
     | @a   |
     +------+
     | 3    |
     +------+
     1 row in set (0.00 sec)

The example uses the *Note `mysql': mysql. client `delimiter' command
to change the statement delimiter from `;' to `//' while the procedure
is being defined. This enables the `;' delimiter used in the procedure
body to be passed through to the server rather than being interpreted by
*Note `mysql': mysql. itself. See *Note stored-programs-defining::.

The `RETURNS' clause may be specified only for a `FUNCTION', for which
it is mandatory. It indicates the return type of the function, and the
function body must contain a `RETURN VALUE' statement. If the *Note
`RETURN': return. statement returns a value of a different type, the
value is coerced to the proper type. For example, if a function
specifies an *Note `ENUM': enum. or *Note `SET': set. value in the
`RETURNS' clause, but the *Note `RETURN': return. statement returns an
integer, the value returned from the function is the string for the
corresponding *Note `ENUM': enum. member of set of *Note `SET': set.
members.

The following example function takes a parameter, performs an operation
using an SQL function, and returns the result. In this case, it is
unnecessary to use `delimiter' because the function definition contains
no internal `;' statement delimiters:

     mysql> CREATE FUNCTION hello (s CHAR(20))
     mysql> RETURNS CHAR(50) DETERMINISTIC
         -> RETURN CONCAT('Hello, ',s,'!');
     Query OK, 0 rows affected (0.00 sec)

     mysql> SELECT hello('world');
     +----------------+
     | hello('world') |
     +----------------+
     | Hello, world!  |
     +----------------+
     1 row in set (0.00 sec)

Parameter types and function return types can be declared to use any
valid data type, except that the `COLLATE' attribute cannot be used.

The ROUTINE_BODY consists of a valid SQL routine statement. This can be
a simple statement such as *Note `SELECT': select. or *Note `INSERT':
insert, or a compound statement written using `BEGIN' and `END'.
Compound statements can contain declarations, loops, and other control
structure statements. The syntax for these statements is described in
*Note sql-syntax-compound-statements::.

MySQL permits routines to contain DDL statements, such as `CREATE' and
`DROP'. MySQL also permits stored procedures (but not stored functions)
to contain SQL transaction statements such as *Note `COMMIT': commit.
Stored functions may not contain statements that perform explicit or
implicit commit or rollback. Support for these statements is not
required by the SQL standard, which states that each DBMS vendor may
decide whether to permit them.

Statements that return a result set can be used within a stored
procedure but not within a stored function. This prohibition includes
*Note `SELECT': select. statements that do not have an `INTO VAR_LIST'
clause and other statements such as *Note `SHOW': show, *Note
`EXPLAIN': explain, and *Note `CHECK TABLE': check-table. For
statements that can be determined at function definition time to return
a result set, a `Not allowed to return a result set from a function'
error occurs (`ER_SP_NO_RETSET'). For statements that can be determined
only at runtime to return a result set, a `PROCEDURE %s can't return a
result set in the given context' error occurs (`ER_SP_BADSELECT').

*Note*:

Before MySQL 5.0.10, stored functions created with *Note `CREATE
FUNCTION': create-function. must not contain references to tables, with
limited exceptions. They may include some *Note `SET': set-option.
statements that contain table references, for example `SET a:= (SELECT
MAX(id) FROM t)', and *Note `SELECT': select. statements that fetch
values directly into variables, for example `SELECT i INTO var1 FROM t'.

*Note `USE': use. statements within stored routines are not permitted.
When a routine is invoked, an implicit `USE DB_NAME' is performed (and
undone when the routine terminates). This causes the routine to have
the given default database while it executes.  References to objects in
databases other than the routine default database should be qualified
with the appropriate database name.

For additional information about statements that are not permitted in
stored routines, see *Note stored-program-restrictions::.

For information about invoking stored procedures from within programs
written in a language that has a MySQL interface, see *Note call::.

MySQL stores the `sql_mode' system variable setting that is in effect
at the time a routine is created, and always executes the routine with
this setting in force, _regardless of the server SQL mode in effect when
the routine is invoked_.

The switch from the SQL mode of the invoker to that of the routine
occurs after evaluation of arguments and assignment of the resulting
values to routine parameters. If you define a routine in strict SQL
mode but invoke it in nonstrict mode, assignment of arguments to
routine parameters does not take place in strict mode. If you require
that expressions passed to a routine be assigned in strict SQL mode,
you should invoke the routine with strict mode in effect.

The `COMMENT' characteristic is a MySQL extension, and may be used to
describe the stored routine. This information is displayed by the *Note
`SHOW CREATE PROCEDURE': show-create-procedure. and *Note `SHOW CREATE
FUNCTION': show-create-function. statements.

The `LANGUAGE' characteristic indicates the language in which the
routine is written. The server ignores this characteristic; only SQL
routines are supported.

A routine is considered `deterministic' if it always produces the same
result for the same input parameters, and `not deterministic'
otherwise. If neither `DETERMINISTIC' nor `NOT DETERMINISTIC' is given
in the routine definition, the default is `NOT DETERMINISTIC'. To
declare that a function is deterministic, you must specify
`DETERMINISTIC' explicitly.

Assessment of the nature of a routine is based on the `honesty' of the
creator: MySQL does not check that a routine declared `DETERMINISTIC'
is free of statements that produce nondeterministic results. However,
misdeclaring a routine might affect results or affect performance.
Declaring a nondeterministic routine as `DETERMINISTIC' might lead to
unexpected results by causing the optimizer to make incorrect execution
plan choices.  Declaring a deterministic routine as `NONDETERMINISTIC'
might diminish performance by causing available optimizations not to be
used. Prior to MySQL 5.0.44, the `DETERMINISTIC' characteristic is
accepted, but not used by the optimizer.

If binary logging is enabled, the `DETERMINISTIC' characteristic
affects which routine definitions MySQL accepts.  See *Note
stored-programs-logging::.

A routine that contains the `NOW()' function (or its synonyms) or
`RAND()' is nondeterministic, but it might still be replication-safe.
For `NOW()', the binary log includes the timestamp and replicates
correctly.  `RAND()' also replicates correctly as long as it is called
only a single time during the execution of a routine. (You can consider
the routine execution timestamp and random number seed as implicit
inputs that are identical on the master and slave.)

Several characteristics provide information about the nature of data
use by the routine. In MySQL, these characteristics are advisory only.
The server does not use them to constrain what kinds of statements a
routine will be permitted to execute.

   * `CONTAINS SQL' indicates that the routine does not contain
     statements that read or write data. This is the default if none of
     these characteristics is given explicitly. Examples of such
     statements are `SET @x = 1' or `DO RELEASE_LOCK('abc')', which
     execute but neither read nor write data.

   * `NO SQL' indicates that the routine contains no SQL statements.

   * `READS SQL DATA' indicates that the routine contains statements
     that read data (for example, *Note `SELECT': select.), but not
     statements that write data.

   * `MODIFIES SQL DATA' indicates that the routine contains statements
     that may write data (for example, *Note `INSERT': insert. or *Note
     `DELETE': delete.).

The `SQL SECURITY' characteristic can be `DEFINER' or `INVOKER' to
specify the security context; that is, whether the routine executes
using the privileges of the account named in the routine `DEFINER'
clause or the user who invokes it. This account must have permission to
access the database with which the routine is associated. The default
value is `DEFINER'. As of MySQL 5.0.3, the user who invokes the routine
must have the `EXECUTE' privilege for it, as must the `DEFINER' account
if the routine executes in definer security context.

The `DEFINER' clause specifies the MySQL account to be used when
checking access privileges at routine execution time for routines that
have the `SQL SECURITY DEFINER' characteristic. The `DEFINER' clause
was added in MySQL 5.0.20.

If a USER value is given for the `DEFINER' clause, it should be a MySQL
account specified as `'USER_NAME'@'HOST_NAME'' (the same format used in
the *Note `GRANT': grant.  statement), `CURRENT_USER', or
`CURRENT_USER()'. The default `DEFINER' value is the user who executes
the *Note `CREATE PROCEDURE': create-procedure. or *Note `CREATE
FUNCTION': create-function. or statement. This is the same as
specifying `DEFINER = CURRENT_USER' explicitly.

If you specify the `DEFINER' clause, these rules determine the legal
`DEFINER' user values:

   * If you do not have the `SUPER' privilege, the only legal USER
     value is your own account, either specified literally or by using
     `CURRENT_USER'. You cannot set the definer to some other account.

   * If you have the `SUPER' privilege, you can specify any
     syntactically legal account name. If the account does not actually
     exist, a warning is generated.

   * Although it is possible to create a routine with a nonexistent
     `DEFINER' account, an error occurs at routine execution time if
     the `SQL SECURITY' value is `DEFINER' but the definer account does
     not exist.

For more information about stored routine security, see *Note
stored-programs-security::.

Within a stored routine that is defined with the `SQL SECURITY DEFINER'
characteristic, `CURRENT_USER' returns the routine's `DEFINER' value.
For information about user auditing within stored routines, see *Note
account-activity-auditing::.

Consider the following procedure, which displays a count of the number
of MySQL accounts listed in the `mysql.user' table:

     CREATE DEFINER = 'admin'@'localhost' PROCEDURE account_count()
     BEGIN
       SELECT 'Number of accounts:', COUNT(*) FROM mysql.user;
     END;

The procedure is assigned a `DEFINER' account of `'admin'@'localhost''
no matter which user defines it. It executes with the privileges of
that account no matter which user invokes it (because the default
security characteristic is `DEFINER'). The procedure succeeds or fails
depending on whether invoker has the `EXECUTE' privilege for it and
`'admin'@'localhost'' has the `SELECT' privilege for the `mysql.user'
table.

Now suppose that the procedure is defined with the `SQL SECURITY
INVOKER' characteristic:

     CREATE DEFINER = 'admin'@'localhost' PROCEDURE account_count()
     SQL SECURITY INVOKER
     BEGIN
       SELECT 'Number of accounts:', COUNT(*) FROM mysql.user;
     END;

The procedure still has a `DEFINER' of `'admin'@'localhost'', but in
this case, it executes with the privileges of the invoking user. Thus,
the procedure succeeds or fails depending on whether the invoker has
the `EXECUTE' privilege for it and the `SELECT' privilege for the
`mysql.user' table.

As of MySQL 5.0.18, the handles the data type of a routine parameter,
local routine variable created with *Note `DECLARE': declare, or
function return value as follows:

   * Assignments are checked for data type mismatches and overflow.
     Conversion and overflow problems result in warnings, or errors in
     strict SQL mode.

   * Only scalar values can be assigned. For example, a statement such
     as `SET x = (SELECT 1, 2)' is invalid.

   * For character data types, if there is a `CHARACTER SET' attribute
     in the declaration, the specified character set and its default
     collation are used. If there is no such attribute, as of MySQL
     5.0.25, the database character set and collation that are in
     effect at the time the server loads the routine into the routine
     cache are used. (These are given by the values of the
     `character_set_database' and `collation_database' system
     variables.) If the database character set or collation change
     while the routine is in the cache, routine execution is unaffected
     by the change until the next time the server reloads the routine
     into the cache. The `COLLATE' attribute is not supported. (This
     includes use of `BINARY', which in this context specifies the
     binary collation of the character set.)

     If you change the database default character set or collation,
     stored routines that use the database defaults must be dropped and
     recreated so that they use the new defaults.

Before MySQL 5.0.18, parameters, return values, and local variables are
treated as items in expressions, and are subject to automatic (silent)
conversion and truncation. Stored functions ignore the `sql_mode'
setting.


File: manual.info,  Node: create-table,  Next: create-trigger,  Prev: create-procedure,  Up: sql-syntax-data-definition

13.1.10 `CREATE TABLE' Syntax
-----------------------------

* Menu:

* create-table-select::          `CREATE TABLE ... SELECT' Syntax
* silent-column-changes::        Silent Column Specification Changes

     CREATE [TEMPORARY] TABLE [IF NOT EXISTS] TBL_NAME
         (CREATE_DEFINITION,...)
         [TABLE_OPTIONS]

Or:

     CREATE [TEMPORARY] TABLE [IF NOT EXISTS] TBL_NAME
         [(CREATE_DEFINITION,...)]
         [TABLE_OPTIONS]
         SELECT_STATEMENT

Or:

     CREATE [TEMPORARY] TABLE [IF NOT EXISTS] TBL_NAME
         { LIKE OLD_TBL_NAME | (LIKE OLD_TBL_NAME) }

     CREATE_DEFINITION:
         COL_NAME COLUMN_DEFINITION
       | [CONSTRAINT [SYMBOL]] PRIMARY KEY [INDEX_TYPE] (INDEX_COL_NAME,...)
             [INDEX_TYPE]
       | {INDEX|KEY} [INDEX_NAME] [INDEX_TYPE] (INDEX_COL_NAME,...)
             [INDEX_TYPE]
       | [CONSTRAINT [SYMBOL]] UNIQUE [INDEX|KEY]
             [INDEX_NAME] [INDEX_TYPE] (INDEX_COL_NAME,...)
             [INDEX_TYPE]
       | {FULLTEXT|SPATIAL} [INDEX|KEY] [INDEX_NAME] (INDEX_COL_NAME,...)
             [INDEX_TYPE]
       | [CONSTRAINT [SYMBOL]] FOREIGN KEY
             [INDEX_NAME] (INDEX_COL_NAME,...) REFERENCE_DEFINITION
       | CHECK (EXPR)

     COLUMN_DEFINITION:
         DATA_TYPE [NOT NULL | NULL] [DEFAULT DEFAULT_VALUE]
           [AUTO_INCREMENT] [UNIQUE [KEY] | [PRIMARY] KEY]
           [COMMENT 'STRING'] [REFERENCE_DEFINITION]

     DATA_TYPE:
         BIT[(LENGTH)]
       | TINYINT[(LENGTH)] [UNSIGNED] [ZEROFILL]
       | SMALLINT[(LENGTH)] [UNSIGNED] [ZEROFILL]
       | MEDIUMINT[(LENGTH)] [UNSIGNED] [ZEROFILL]
       | INT[(LENGTH)] [UNSIGNED] [ZEROFILL]
       | INTEGER[(LENGTH)] [UNSIGNED] [ZEROFILL]
       | BIGINT[(LENGTH)] [UNSIGNED] [ZEROFILL]
       | REAL[(LENGTH,DECIMALS)] [UNSIGNED] [ZEROFILL]
       | DOUBLE[(LENGTH,DECIMALS)] [UNSIGNED] [ZEROFILL]
       | FLOAT[(LENGTH,DECIMALS)] [UNSIGNED] [ZEROFILL]
       | DECIMAL[(LENGTH[,DECIMALS])] [UNSIGNED] [ZEROFILL]
       | NUMERIC[(LENGTH[,DECIMALS])] [UNSIGNED] [ZEROFILL]
       | DATE
       | TIME
       | TIMESTAMP
       | DATETIME
       | YEAR
       | CHAR[(LENGTH)]
           [CHARACTER SET CHARSET_NAME] [COLLATE COLLATION_NAME]
       | VARCHAR(LENGTH)
           [CHARACTER SET CHARSET_NAME] [COLLATE COLLATION_NAME]
       | BINARY[(LENGTH)]
       | VARBINARY(LENGTH)
       | TINYBLOB
       | BLOB
       | MEDIUMBLOB
       | LONGBLOB
       | TINYTEXT [BINARY]
           [CHARACTER SET CHARSET_NAME] [COLLATE COLLATION_NAME]
       | TEXT [BINARY]
           [CHARACTER SET CHARSET_NAME] [COLLATE COLLATION_NAME]
       | MEDIUMTEXT [BINARY]
           [CHARACTER SET CHARSET_NAME] [COLLATE COLLATION_NAME]
       | LONGTEXT [BINARY]
           [CHARACTER SET CHARSET_NAME] [COLLATE COLLATION_NAME]
       | ENUM(VALUE1,VALUE2,VALUE3,...)
           [CHARACTER SET CHARSET_NAME] [COLLATE COLLATION_NAME]
       | SET(VALUE1,VALUE2,VALUE3,...)
           [CHARACTER SET CHARSET_NAME] [COLLATE COLLATION_NAME]
       | SPATIAL_TYPE

     INDEX_COL_NAME:
         COL_NAME [(LENGTH)] [ASC | DESC]

     INDEX_TYPE:
         USING {BTREE | HASH}

     REFERENCE_DEFINITION:
         REFERENCES TBL_NAME (INDEX_COL_NAME,...)
           [MATCH FULL | MATCH PARTIAL | MATCH SIMPLE]
           [ON DELETE REFERENCE_OPTION]
           [ON UPDATE REFERENCE_OPTION]

     REFERENCE_OPTION:
         RESTRICT | CASCADE | SET NULL | NO ACTION

     TABLE_OPTIONS:
         TABLE_OPTION [[,] TABLE_OPTION] ...

     TABLE_OPTION:
         {ENGINE|TYPE} [=] ENGINE_NAME
       | AUTO_INCREMENT [=] VALUE
       | AVG_ROW_LENGTH [=] VALUE
       | [DEFAULT] CHARACTER SET [=] CHARSET_NAME
       | CHECKSUM [=] {0 | 1}
       | [DEFAULT] COLLATE [=] COLLATION_NAME
       | COMMENT [=] 'STRING'
       | CONNECTION [=] 'CONNECT_STRING'
       | DATA DIRECTORY [=] 'ABSOLUTE PATH TO DIRECTORY'
       | DELAY_KEY_WRITE [=] {0 | 1}
       | INDEX DIRECTORY [=] 'ABSOLUTE PATH TO DIRECTORY'
       | INSERT_METHOD [=] { NO | FIRST | LAST }
       | MAX_ROWS [=] VALUE
       | MIN_ROWS [=] VALUE
       | PACK_KEYS [=] {0 | 1 | DEFAULT}
       | PASSWORD [=] 'STRING'
       | ROW_FORMAT [=] {DEFAULT|DYNAMIC|FIXED|COMPRESSED|REDUNDANT|COMPACT}
       | UNION [=] (TBL_NAME[,TBL_NAME]...)

     SELECT_STATEMENT:
         [IGNORE | REPLACE] [AS] SELECT ...   (SOME LEGAL SELECT STATEMENT)

*Note `CREATE TABLE': create-table. creates a table with the given
name. You must have the `CREATE' privilege for the table.

Rules for permissible table names are given in *Note identifiers::. By
default, the table is created in the default database. An error occurs
if the table exists, if there is no default database, or if the
database does not exist.

The table name can be specified as DB_NAME.TBL_NAME to create the table
in a specific database. This works regardless of whether there is a
default database, assuming that the database exists. If you use quoted
identifiers, quote the database and table names separately.  For
example, write ``mydb`.`mytbl`', not ``mydb.mytbl`'.

You can use the `TEMPORARY' keyword when creating a table. A
`TEMPORARY' table is visible only to the current connection, and is
dropped automatically when the connection is closed. This means that
two different connections can use the same temporary table name without
conflicting with each other or with an existing non-`TEMPORARY' table
of the same name. (The existing table is hidden until the temporary
table is dropped.) To create temporary tables, you must have the
`CREATE TEMPORARY TABLES' privilege.

*Note*:

*Note `CREATE TABLE': create-table. does not automatically commit the
current active transaction if you use the `TEMPORARY' keyword.

The keywords `IF NOT EXISTS' prevent an error from occurring if the
table exists. However, there is no verification that the existing table
has a structure identical to that indicated by the *Note `CREATE
TABLE': create-table.  statement.

MySQL represents each table by an `.frm' table format (definition) file
in the database directory. The storage engine for the table might
create other files as well. In the case of `MyISAM' tables, the storage
engine creates data and index files. Thus, for each `MyISAM' table
TBL_NAME, there are three disk files.

File                   Purpose
`TBL_NAME.frm'         Table format (definition) file
`TBL_NAME.MYD'         Data file
`TBL_NAME.MYI'         Index file

*Note storage-engines::, describes what files each storage engine
creates to represent tables.

DATA_TYPE represents the data type in a column definition. SPATIAL_TYPE
represents a spatial data type. The data type syntax shown is
representative only. For a full description of the syntax available for
specifying column data types, as well as information about the
properties of each type, see *Note data-types::, and *Note
spatial-extensions::.

Some attributes do not apply to all data types.  `AUTO_INCREMENT'
applies only to integer and floating-point types. `DEFAULT' does not
apply to the *Note `BLOB': blob. or *Note `TEXT': blob. types.

   * If neither `NULL' nor `NOT NULL' is specified, the column is
     treated as though `NULL' had been specified.

   * An integer or floating-point column can have the additional
     attribute `AUTO_INCREMENT'. When you insert a value of `NULL'
     (recommended) or `0' into an indexed `AUTO_INCREMENT' column, the
     column is set to the next sequence value. Typically this is
     `VALUE+1', where VALUE is the largest value for the column
     currently in the table.  `AUTO_INCREMENT' sequences begin with `1'.

     To retrieve an `AUTO_INCREMENT' value after inserting a row, use
     the `LAST_INSERT_ID()' SQL function or the *Note
     `mysql_insert_id()': mysql-insert-id. C API function. See *Note
     information-functions::, and *Note mysql-insert-id::.

     If the `NO_AUTO_VALUE_ON_ZERO' SQL mode is enabled, you can store
     `0' in `AUTO_INCREMENT' columns as `0' without generating a new
     sequence value.  See *Note server-sql-mode::.

     *Note*:

     There can be only one `AUTO_INCREMENT' column per table, it must
     be indexed, and it cannot have a `DEFAULT' value. An
     `AUTO_INCREMENT' column works properly only if it contains only
     positive values. Inserting a negative number is regarded as
     inserting a very large positive number. This is done to avoid
     precision problems when numbers `wrap' over from positive to
     negative and also to ensure that you do not accidentally get an
     `AUTO_INCREMENT' column that contains `0'.

     For `MyISAM' and `BDB' tables, you can specify an `AUTO_INCREMENT'
     secondary column in a multiple-column key. See *Note
     example-auto-increment::.

     To make MySQL compatible with some ODBC applications, you can find
     the `AUTO_INCREMENT' value for the last inserted row with the
     following query:

          SELECT * FROM TBL_NAME WHERE AUTO_COL IS NULL

     For information about `InnoDB' and `AUTO_INCREMENT', see *Note
     innodb-auto-increment-handling::.

   * Character data types (*Note `CHAR': char, *Note `VARCHAR': char,
     *Note `TEXT': blob.) can include `CHARACTER SET' and `COLLATE'
     attributes to specify the character set and collation for the
     column. For details, see *Note charset::. `CHARSET' is a synonym
     for `CHARACTER SET'. Example:

          CREATE TABLE t (c CHAR(20) CHARACTER SET utf8 COLLATE utf8_bin);

     MySQL 5.0 interprets length specifications in character column
     definitions in characters. (Versions before MySQL 4.1 interpreted
     them in bytes.) Lengths for *Note `BINARY': binary-varbinary. and
     *Note `VARBINARY': binary-varbinary. are in bytes.

   * The `DEFAULT' clause specifies a default value for a column. With
     one exception, the default value must be a constant; it cannot be
     a function or an expression. This means, for example, that you
     cannot set the default for a date column to be the value of a
     function such as `NOW()' or `CURRENT_DATE'. The exception is that
     you can specify `CURRENT_TIMESTAMP' as the default for a *Note
     `TIMESTAMP': datetime. column.  See *Note timestamp::.

     If a column definition includes no explicit `DEFAULT' value, MySQL
     determines the default value as described in *Note
     data-type-defaults::.

     *Note `BLOB': blob. and *Note `TEXT': blob. columns cannot be
     assigned a default value.

     *Note `CREATE TABLE': create-table. fails if a date-valued default
     is not correct according to the `NO_ZERO_IN_DATE' SQL mode, even
     if strict SQL mode is not enabled. For example, `c1 DATE DEFAULT
     '2010-00-00'' causes *Note `CREATE TABLE': create-table. to fail
     with `Invalid default value for 'c1''.

   * A comment for a column can be specified with the `COMMENT' option,
     up to 255 characters long.  The comment is displayed by the *Note
     `SHOW CREATE TABLE': show-create-table. and *Note `SHOW FULL
     COLUMNS': show-columns. statements.

   * `KEY' is normally a synonym for `INDEX'. The key attribute `PRIMARY
     KEY' can also be specified as just `KEY' when given in a column
     definition. This was implemented for compatibility with other
     database systems.

   * A `UNIQUE' index creates a constraint such that all values in the
     index must be distinct. An error occurs if you try to add a new
     row with a key value that matches an existing row. This constraint
     does not apply to `NULL' values except for the `BDB' storage
     engine. For other engines, a `UNIQUE' index permits multiple
     `NULL' values for columns that can contain `NULL'.

   * A `PRIMARY KEY' is a unique index where all key columns must be
     defined as `NOT NULL'. If they are not explicitly declared as `NOT
     NULL', MySQL declares them so implicitly (and silently). A table
     can have only one `PRIMARY KEY'. The name of a `PRIMARY KEY' is
     always `PRIMARY', which thus cannot be used as the name for any
     other kind of index.

     If you do not have a `PRIMARY KEY' and an application asks for the
     `PRIMARY KEY' in your tables, MySQL returns the first `UNIQUE'
     index that has no `NULL' columns as the `PRIMARY KEY'.

     In `InnoDB' tables, having a long `PRIMARY KEY' wastes a lot of
     space. (See *Note innodb-table-and-index::.)

   * In the created table, a `PRIMARY KEY' is placed first, followed by
     all `UNIQUE' indexes, and then the nonunique indexes. This helps
     the MySQL optimizer to prioritize which index to use and also more
     quickly to detect duplicated `UNIQUE' keys.

   * A `PRIMARY KEY' can be a multiple-column index. However, you
     cannot create a multiple-column index using the `PRIMARY KEY' key
     attribute in a column specification. Doing so only marks that
     single column as primary. You must use a separate `PRIMARY
     KEY(INDEX_COL_NAME, ...)' clause.

   * If a `PRIMARY KEY' or `UNIQUE' index consists of only one column
     that has an integer type, you can also refer to the column as
     `_rowid' in *Note `SELECT': select. statements.

   * In MySQL, the name of a `PRIMARY KEY' is `PRIMARY'. For other
     indexes, if you do not assign a name, the index is assigned the
     same name as the first indexed column, with an optional suffix
     (`_2', `_3', `...') to make it unique. You can see index names for
     a table using `SHOW INDEX FROM TBL_NAME'. See *Note show-index::.

   * Some storage engines permit you to specify an index type when
     creating an index. The syntax for the INDEX_TYPE specifier is
     `USING TYPE_NAME'.

     Example:

          CREATE TABLE lookup
            (id INT, INDEX USING BTREE (id))
            ENGINE = MEMORY;

     Before MySQL 5.0.60, `USING' can be given only before the index
     column list. As of 5.0.60, the preferred position is after the
     column list. Support for use of the option before the column list
     will be removed in a future MySQL release.

     INDEX_OPTION values specify additional options for an index.
     `USING' is one such option. For details about permissible
     INDEX_OPTION values, see *Note create-index::.

     For more information about indexes, see *Note mysql-indexes::.

   * In MySQL 5.0, only the `MyISAM', `InnoDB', `BDB', and `MEMORY'
     storage engines support indexes on columns that can have `NULL'
     values. In other cases, you must declare indexed columns as `NOT
     NULL' or an error results.

   * For *Note `CHAR': char, *Note `VARCHAR': char, *Note `BINARY':
     binary-varbinary, and *Note `VARBINARY': binary-varbinary.
     columns, indexes can be created that use only the leading part of
     column values, using `COL_NAME(LENGTH)' syntax to specify an index
     prefix length.  *Note `BLOB': blob. and *Note `TEXT': blob.
     columns also can be indexed, but a prefix length _must_ be given.
     Prefix lengths are given in characters for nonbinary string types
     and in bytes for binary string types. That is, index entries
     consist of the first LENGTH characters of each column value for
     *Note `CHAR': char, *Note `VARCHAR': char, and *Note `TEXT': blob.
     columns, and the first LENGTH bytes of each column value for *Note
     `BINARY': binary-varbinary, *Note `VARBINARY': binary-varbinary,
     and *Note `BLOB': blob. columns. Indexing only a prefix of column
     values like this can make the index file much smaller. See *Note
     column-indexes::.

     Only the `MyISAM', `BDB', and `InnoDB' storage engines support
     indexing on *Note `BLOB': blob. and *Note `TEXT': blob. columns.
     For example:

          CREATE TABLE test (blob_col BLOB, INDEX(blob_col(10)));

     Prefixes can be up to 1000 bytes long (767 bytes for `InnoDB'
     tables). Note that prefix limits are measured in bytes, whereas
     the prefix length in *Note `CREATE TABLE': create-table.
     statements is interpreted as number of characters for nonbinary
     data types (*Note `CHAR': char, *Note `VARCHAR': char, *Note
     `TEXT': blob.). Take this into account when specifying a prefix
     length for a column that uses a multi-byte character set.

   * An INDEX_COL_NAME specification can end with `ASC' or `DESC'.
     These keywords are permitted for future extensions for specifying
     ascending or descending index value storage.  Currently, they are
     parsed but ignored; index values are always stored in ascending
     order.

   * When you use `ORDER BY' or `GROUP BY' on a *Note `TEXT': blob. or
     *Note `BLOB': blob. column in a *Note `SELECT': select, the server
     sorts values using only the initial number of bytes indicated by
     the `max_sort_length' system variable. See *Note blob::.

   * You can create special `FULLTEXT' indexes, which are used for
     full-text searches. Only the `MyISAM' storage engine supports
     `FULLTEXT' indexes. They can be created only from *Note `CHAR':
     char, *Note `VARCHAR': char, and *Note `TEXT': blob. columns.
     Indexing always happens over the entire column; column prefix
     indexing is not supported and any prefix length is ignored if
     specified. See *Note fulltext-search::, for details of operation.

   * You can create `SPATIAL' indexes on spatial data types. Spatial
     types are supported only for `MyISAM' tables and indexed columns
     must be declared as `NOT NULL'. See *Note spatial-extensions::.

   * `InnoDB' tables support checking of foreign key constraints. See
     *Note innodb-storage-engine::.  Note that the `FOREIGN KEY' syntax
     in `InnoDB' is more restrictive than the syntax presented for the
     *Note `CREATE TABLE': create-table.  statement at the beginning of
     this section: The columns of the referenced table must always be
     explicitly named.  `InnoDB' supports both `ON DELETE' and `ON
     UPDATE' actions on foreign keys. For the precise syntax, see *Note
     innodb-foreign-key-constraints::.

     For other storage engines, MySQL Server parses and ignores the
     `FOREIGN KEY' and `REFERENCES' syntax in *Note `CREATE TABLE':
     create-table. statements. The `CHECK' clause is parsed but ignored
     by all storage engines. See *Note ansi-diff-foreign-keys::.

     *Important*:

     For users familiar with the ANSI/ISO SQL Standard, please note
     that no storage engine, including `InnoDB', recognizes or enforces
     the `MATCH' clause used in referential integrity constraint
     definitions. Use of an explicit `MATCH' clause will not have the
     specified effect, and also causes `ON DELETE' and `ON UPDATE'
     clauses to be ignored. For these reasons, specifying `MATCH'
     should be avoided.

     The `MATCH' clause in the SQL standard controls how `NULL' values
     in a composite (multiple-column) foreign key are handled when
     comparing to a primary key. `InnoDB' essentially implements the
     semantics defined by `MATCH SIMPLE', which permit a foreign key to
     be all or partially `NULL'. In that case, the (child table) row
     containing such a foreign key is permitted to be inserted, and
     does not match any row in the referenced (parent) table. It is
     possible to implement other semantics using triggers.

     Additionally, MySQL and `InnoDB' require that the referenced
     columns be indexed for performance.  However, the system does not
     enforce a requirement that the referenced columns be `UNIQUE' or be
     declared `NOT NULL'. The handling of foreign key references to
     nonunique keys or keys that contain `NULL' values is not well
     defined for operations such as *Note `UPDATE': update.  or `DELETE
     CASCADE'. You are advised to use foreign keys that reference only
     `UNIQUE' and `NOT NULL' keys.

     Furthermore, `InnoDB' does not recognize or support `inline
     `REFERENCES' specifications' (as defined in the SQL standard)
     where the references are defined as part of the column
     specification. `InnoDB' accepts `REFERENCES' clauses only when
     specified as part of a separate `FOREIGN KEY' specification. For
     other storage engines, MySQL Server parses and ignores foreign key
     specifications.

   * There is a hard limit of 4096 columns per table, but the effective
     maximum may be less for a given table and depends on the factors
     discussed in *Note column-count-limit::.

The `ENGINE' table option specifies the storage engine for the table.
`TYPE' is a synonym, but `ENGINE' is the preferred option name.

The `ENGINE' table option takes the storage engine names shown in the
following table.

Storage Engine     Description
`ARCHIVE'          The archiving storage engine. See *Note
                   archive-storage-engine::.
`BDB'              Transaction-safe tables with page locking. Also
                   known as `BerkeleyDB'. See *Note
                   bdb-storage-engine::.
`CSV'              Tables that store rows in comma-separated values
                   format. See *Note csv-storage-engine::.
`EXAMPLE'          An example engine. See *Note
                   example-storage-engine::.
`FEDERATED'        Storage engine that accesses remote tables. See
                   *Note federated-storage-engine::.
`HEAP'             This is a synonym for `MEMORY'.
`ISAM'             Not available in MySQL 5.0. If you are upgrading
(_OBSOLETE_)       to MySQL 5.0 from a previous version, you should
                   convert any existing `ISAM' tables to `MyISAM'
                   _before_ performing the upgrade.
`InnoDB'           Transaction-safe tables with row locking and
                   foreign keys. See *Note innodb-storage-engine::.
`MEMORY'           The data for this storage engine is stored only
                   in memory. See *Note memory-storage-engine::.
`MERGE'            A collection of `MyISAM' tables used as one
                   table. Also known as `MRG_MyISAM'. See *Note
                   merge-storage-engine::.
`MyISAM'           The binary portable storage engine that is the
                   default storage engine used by MySQL. See *Note
                   myisam-storage-engine::.
*Note              Clustered, fault-tolerant, memory-based tables.
`NDBCLUSTER':      Also known as *Note `NDB': mysql-cluster. See
mysql-cluster.     *Note mysql-cluster::.

If a storage engine is specified that is not available, MySQL uses the
default engine instead. Normally, this is `MyISAM'. For example, if a
table definition includes the `ENGINE=BDB' option but the MySQL server
does not support `BDB' tables, the table is created as a `MyISAM'
table. This makes it possible to have a replication setup where you
have transactional tables on the master but tables created on the slave
are nontransactional (to get more speed). In MySQL 5.0, a warning
occurs if the storage engine specification is not honored.

Engine substitution can be controlled by the setting of the
`NO_ENGINE_SUBSTITUTION' SQL mode, as described in *Note
server-sql-mode::.

The other table options are used to optimize the behavior of the table.
In most cases, you do not have to specify any of them.  These options
apply to all storage engines unless otherwise indicated. Options that
do not apply to a given storage engine may be accepted and remembered
as part of the table definition. Such options then apply if you later
use *Note `ALTER TABLE': alter-table. to convert the table to use a
different storage engine.

   * `AUTO_INCREMENT'

     The initial `AUTO_INCREMENT' value for the table. In MySQL 5.0,
     this works for `MyISAM' and `MEMORY' tables. It is also supported
     for `InnoDB' as of MySQL 5.0.3. To set the first auto-increment
     value for engines that do not support the `AUTO_INCREMENT' table
     option, insert a `dummy' row with a value one less than the
     desired value after creating the table, and then delete the dummy
     row.

     For engines that support the `AUTO_INCREMENT' table option in
     *Note `CREATE TABLE': create-table.  statements, you can also use
     `ALTER TABLE TBL_NAME AUTO_INCREMENT = N' to reset the
     `AUTO_INCREMENT' value. The value cannot be set lower than the
     maximum value currently in the column.

   * `AVG_ROW_LENGTH'

     An approximation of the average row length for your table. You
     need to set this only for large tables with variable-size rows.

     When you create a `MyISAM' table, MySQL uses the product of the
     `MAX_ROWS' and `AVG_ROW_LENGTH' options to decide how big the
     resulting table is. If you don't specify either option, the
     maximum size for `MyISAM' data and index table files is 256TB of
     data by default (4GB before MySQL 5.0.6). (If your operating
     system does not support files that large, table sizes are
     constrained by the file size limit.) If you want to keep down the
     pointer sizes to make the index smaller and faster and you don't
     really need big files, you can decrease the default pointer size
     by setting the `myisam_data_pointer_size' system variable, which
     was added in MySQL 4.1.2. (See *Note server-system-variables::.)
     If you want all your tables to be able to grow above the default
     limit and are willing to have your tables slightly slower and
     larger than necessary, you can increase the default pointer size by
     setting this variable. Setting the value to 7 permits table sizes
     up to 65,536TB.

   * `[DEFAULT] CHARACTER SET'

     Specify a default character set for the table.  `CHARSET' is a
     synonym for `CHARACTER SET'. If the character set name is
     `DEFAULT', the database character set is used.

   * `CHECKSUM'

     Set this to 1 if you want MySQL to maintain a live checksum for
     all rows (that is, a checksum that MySQL updates automatically as
     the table changes). This makes the table a little slower to
     update, but also makes it easier to find corrupted tables. The
     *Note `CHECKSUM TABLE': checksum-table. statement reports the
     checksum.  (`MyISAM' only.)

   * `[DEFAULT] COLLATE'

     Specify a default collation for the table.

   * `COMMENT'

     A comment for the table, up to 60 characters long.

   * `CONNECTION'

     The connection string for a `FEDERATED' table. This option is
     available as of MySQL 5.0.13; before that, use a `COMMENT' option
     for the connection string.

   * `DATA DIRECTORY', `INDEX DIRECTORY'

     By using `DATA DIRECTORY='DIRECTORY'' or `INDEX
     DIRECTORY='DIRECTORY'' you can specify where the `MyISAM' storage
     engine should put a table's data file and index file. The directory
     must be the full path name to the directory, not a relative path.

     These options work only when you are not using the
     `--skip-symbolic-links' option. Your operating system must also
     have a working, thread-safe `realpath()' call. See *Note
     symbolic-links-to-tables::, for more complete information.

     If a `MyISAM' table is created with no `DATA DIRECTORY' option, the
     `.MYD' file is created in the database directory. By default, if
     `MyISAM' finds an existing `.MYD' file in this case, it overwrites
     it. The same applies to `.MYI' files for tables created with no
     `INDEX DIRECTORY' option. As of MySQL 5.0.48, to suppress this
     behavior, start the server with the `--keep_files_on_create'
     option, in which case `MyISAM' will not overwrite existing files
     and returns an error instead.

     If a `MyISAM' table is created with a `DATA DIRECTORY' or `INDEX
     DIRECTORY' option and an existing `.MYD' or `.MYI' file is found,
     MyISAM always returns an error. It will not overwrite a file in
     the specified directory.

     *Important*:

     Beginning with MySQL 5.0.60, you cannot use path names that
     contain the MySQL data directory with `DATA DIRECTORY' or `INDEX
     DIRECTORY'.  (See Bug #32167.)

   * `DELAY_KEY_WRITE'

     Set this to 1 if you want to delay key updates for the table until
     the table is closed. See the description of the `delay_key_write'
     system variable in *Note server-system-variables::.  (`MyISAM'
     only.)

   * `INSERT_METHOD'

     If you want to insert data into a `MERGE' table, you must specify
     with `INSERT_METHOD' the table into which the row should be
     inserted.  `INSERT_METHOD' is an option useful for `MERGE' tables
     only. Use a value of `FIRST' or `LAST' to have inserts go to the
     first or last table, or a value of `NO' to prevent inserts. See
     *Note merge-storage-engine::.

   * `MAX_ROWS'

     The maximum number of rows you plan to store in the table.  This
     is not a hard limit, but rather a hint to the storage engine that
     the table must be able to store at least this many rows.

     The *Note `NDB': mysql-cluster. storage engine treats this value
     as a maxmimum. If you plan to create very large MySQL Cluster
     tables (containing millions of rows), you should use this option
     to insure that *Note `NDB': mysql-cluster. allocates sufficient
     number of index slots in the hash table used for storing hashes of
     the table's primary keys by setting `MAX_ROWS = 2 * ROWS', where
     ROWS is the number of rows that you expect to insert into the
     table.

     The maximum `MAX_ROWS' value is 4294967295; larger values are
     truncated to this limit.

   * `MIN_ROWS'

     The minimum number of rows you plan to store in the table. The
     *Note `MEMORY': memory-storage-engine. storage engine uses this
     option as a hint about memory use.

   * `PACK_KEYS'

     `PACK_KEYS' takes effect only with `MyISAM' tables. Set this
     option to 1 if you want to have smaller indexes. This usually
     makes updates slower and reads faster. Setting the option to 0
     disables all packing of keys. Setting it to `DEFAULT' tells the
     storage engine to pack only long *Note `CHAR': char, *Note
     `VARCHAR': char, *Note `BINARY': binary-varbinary, or *Note
     `VARBINARY': binary-varbinary. columns.

     If you do not use `PACK_KEYS', the default is to pack strings, but
     not numbers. If you use `PACK_KEYS=1', numbers are packed as well.

     When packing binary number keys, MySQL uses prefix compression:

        * Every key needs one extra byte to indicate how many bytes of
          the previous key are the same for the next key.

        * The pointer to the row is stored in high-byte-first order
          directly after the key, to improve compression.

     This means that if you have many equal keys on two consecutive
     rows, all following `same' keys usually only take two bytes
     (including the pointer to the row). Compare this to the ordinary
     case where the following keys takes `storage_size_for_key +
     pointer_size' (where the pointer size is usually 4). Conversely,
     you get a significant benefit from prefix compression only if you
     have many numbers that are the same. If all keys are totally
     different, you use one byte more per key, if the key is not a key
     that can have `NULL' values. (In this case, the packed key length
     is stored in the same byte that is used to mark if a key is
     `NULL'.)

   * `PASSWORD'

     This option is unused. If you have a need to scramble your `.frm'
     files and make them unusable to any other MySQL server, please
     contact our sales department.

   * `ROW_FORMAT'

     Defines how the rows should be stored. For `MyISAM' tables, the
     option value can be `FIXED' or `DYNAMIC' for static or
     variable-length row format.  *Note `myisampack': myisampack. sets
     the type to `COMPRESSED'. See *Note myisam-table-formats::.

     Starting with MySQL 5.0.3, for `InnoDB' tables, rows are stored in
     compact format (`ROW_FORMAT=COMPACT') by default. The noncompact
     format used in older versions of MySQL can still be requested by
     specifying `ROW_FORMAT=REDUNDANT'.

     *Note*:

     When executing a *Note `CREATE TABLE': create-table.  statement,
     if you specify a row format which is not supported by the storage
     engine that is used for the table, the table is created using that
     storage engine's default row format. The information reported in
     this column in response to *Note `SHOW TABLE STATUS':
     show-table-status. is the actual row format used. This may differ
     from the value in the `Create_options' column because the original
     *Note `CREATE TABLE': create-table.  definition is retained during
     creation.

   * `RAID_TYPE'

     `RAID' support has been removed as of MySQL 5.0.

   * *Note `UNION': union.

     *Note `UNION': union. is used when you want to access a collection
     of identical `MyISAM' tables as one. This works only with `MERGE'
     tables. See *Note merge-storage-engine::.

     You must have `SELECT', `UPDATE', and `DELETE' privileges for the
     tables you map to a `MERGE' table.

     *Note*:

     Formerly, all tables used had to be in the same database as the
     `MERGE' table itself. This restriction no longer applies.

*Important*:

The original *Note `CREATE TABLE': create-table.  statement, including
all specifications and table options are stored by MySQL when the table
is created. The information is retained so that if you change storage
engines, collations or other settings using an *Note `ALTER TABLE':
alter-table. statement, the original table options specified are
retained. This enables you to change between `InnoDB' and `MyISAM' table
types even though the row formats supported by the two engines are
different.

Because the text of the original statement is retained, but due to the
way that certain values and options may be silently reconfigured (such
as the `ROW_FORMAT'), the active table definition (accessible through
*Note `DESCRIBE': describe. or with *Note `SHOW TABLE STATUS':
show-table-status.) and the table creation string (accessible through
*Note `SHOW CREATE TABLE': show-create-table.) will report different
values.

You can create one table from another by adding a *Note `SELECT':
select. statement at the end of the *Note `CREATE TABLE': create-table.
statement:

     CREATE TABLE NEW_TBL SELECT * FROM ORIG_TBL;

For more information, see *Note create-table-select::.

Use `LIKE' to create an empty table based on the definition of another
table, including any column attributes and indexes defined in the
original table:

     CREATE TABLE NEW_TBL LIKE ORIG_TBL;

The copy is created using the same version of the table storage format
as the original table. The `SELECT' privilege is required on the
original table.

`LIKE' works only for base tables, not for views.

`CREATE TABLE ... LIKE' does not preserve any `DATA DIRECTORY' or `INDEX
DIRECTORY' table options that were specified for the original table, or
any foreign key definitions.

If the original table is a `TEMPORARY' table, `CREATE TABLE ... LIKE'
does not preserve `TEMPORARY'. To create a `TEMPORARY' destination
table, use `CREATE TEMPORARY TABLE ... LIKE'.

In MySQL 5.0, changes to the SQL mode do not affect *Note `CREATE TABLE
... LIKE': create-table. If the current SQL mode is different from the
mode in effect when the original table was created, the statement
succeeds even if the table definition is invalid for the new mode.


File: manual.info,  Node: create-table-select,  Next: silent-column-changes,  Prev: create-table,  Up: create-table

13.1.10.1 `CREATE TABLE ... SELECT' Syntax
..........................................

You can create one table from another by adding a *Note `SELECT':
select. statement at the end of the *Note `CREATE TABLE': create-table.
statement:

     CREATE TABLE NEW_TBL SELECT * FROM ORIG_TBL;

MySQL creates new columns for all elements in the *Note `SELECT':
select. For example:

     mysql> CREATE TABLE test (a INT NOT NULL AUTO_INCREMENT,
         ->        PRIMARY KEY (a), KEY(b))
         ->        ENGINE=MyISAM SELECT b,c FROM test2;

This creates a *Note `MyISAM': myisam-storage-engine. table with three
columns, `a', `b', and `c'. The `ENGINE' option is part of the *Note
`CREATE TABLE': create-table.  statement, and should not be used
following the *Note `SELECT': select.; this would result in a syntax
error. The same is true for other *Note `CREATE TABLE': create-table.
options such as `CHARSET'.

Notice that the columns from the *Note `SELECT': select. statement are
appended to the right side of the table, not overlapped onto it. Take
the following example:

     mysql> SELECT * FROM foo;
     +---+
     | n |
     +---+
     | 1 |
     +---+

     mysql> CREATE TABLE bar (m INT) SELECT n FROM foo;
     Query OK, 1 row affected (0.02 sec)
     Records: 1  Duplicates: 0  Warnings: 0

     mysql> SELECT * FROM bar;
     +------+---+
     | m    | n |
     +------+---+
     | NULL | 1 |
     +------+---+
     1 row in set (0.00 sec)

For each row in table `foo', a row is inserted in `bar' with the values
from `foo' and default values for the new columns.

In a table resulting from *Note `CREATE TABLE ... SELECT':
create-table, columns named only in the *Note `CREATE TABLE':
create-table. part come first.  Columns named in both parts or only in
the *Note `SELECT': select. part come after that. The data type of
*Note `SELECT': select. columns can be overridden by also specifying
the column in the *Note `CREATE TABLE': create-table. part.

If any errors occur while copying the data to the table, it is
automatically dropped and not created.

You can precede the *Note `SELECT': select. by `IGNORE' or *Note
`REPLACE': replace. to indicate how to handle rows that duplicate
unique key values. With `IGNORE', new rows that duplicate an existing
row on a unique key value are discarded. With *Note `REPLACE': replace,
new rows replace rows that have the same unique key value. If neither
`IGNORE' nor *Note `REPLACE': replace. is specified, duplicate unique
key values result in an error.

*Note `CREATE TABLE ... SELECT': create-table. does not automatically
create any indexes for you. This is done intentionally to make the
statement as flexible as possible. If you want to have indexes in the
created table, you should specify these before the *Note `SELECT':
select. statement:

     mysql> CREATE TABLE bar (UNIQUE (n)) SELECT n FROM foo;

Some conversion of data types might occur. For example, the
`AUTO_INCREMENT' attribute is not preserved, and *Note `VARCHAR': char.
columns can become *Note `CHAR': char. columns. Retrained attributes
are `NULL' (or `NOT NULL') and, for those columns that have them,
`CHARACTER SET', `COLLATION', `COMMENT', and the `DEFAULT' clause.

When creating a table with *Note `CREATE TABLE ... SELECT':
create-table-select, make sure to alias any function calls or
expressions in the query. If you do not, the `CREATE' statement might
fail or result in undesirable column names.

     CREATE TABLE artists_and_works
       SELECT artist.name, COUNT(work.artist_id) AS number_of_works
       FROM artist LEFT JOIN work ON artist.id = work.artist_id
       GROUP BY artist.id;

You can also explicitly specify the data type for a generated column:

     CREATE TABLE foo (a TINYINT NOT NULL) SELECT b+1 AS a FROM bar;

For *Note `CREATE TABLE ... SELECT': create-table, if `IF NOT EXISTS' is
given and the destination table already exists, MySQL handles the
statement as follows:

   * The table definition given in the *Note `CREATE TABLE':
     create-table. part is ignored.  No error occurs, even if the
     definition does not match that of the existing table. MySQL
     attempts to insert the rows from the *Note `SELECT': select. part
     anyway.

   * If there is a mismatch between the number of columns in the table
     and the number of columns produced by the *Note `SELECT': select.
     part, the selected values are assigned to the rightmost columns.
     For example, if the table contains N columns and the *Note
     `SELECT': select. produces M columns, where M < N, the selected
     values are assigned to the M rightmost columns in the table. Each
     of the initial N - M columns is assigned its default value, either
     that specified explicitly in the column definition or the implicit
     column data type default if the definition contains no default. If
     the *Note `SELECT': select. part produces too many columns (M >
     N), an error occurs.

   * If strict SQL mode is enabled and any of these initial columns do
     not have an explicit default value, the statement fails with an
     error.

The following example illustrates `IF NOT EXISTS' handling:

     mysql> CREATE TABLE t1 (i1 INT DEFAULT 0, i2 INT, i3 INT, i4 INT);
     Query OK, 0 rows affected (0.05 sec)

     mysql> CREATE TABLE IF NOT EXISTS t1 (c1 CHAR(10)) SELECT 1, 2;
     Query OK, 1 row affected, 1 warning (0.01 sec)
     Records: 1  Duplicates: 0  Warnings: 0

     mysql> SELECT * FROM t1;
     +------+------+------+------+
     | i1   | i2   | i3   | i4   |
     +------+------+------+------+
     |    0 | NULL |    1 |    2 |
     +------+------+------+------+
     1 row in set (0.00 sec)

To ensure that the binary log can be used to re-create the original
tables, MySQL does not permit concurrent inserts during *Note `CREATE
TABLE ... SELECT': create-table.


File: manual.info,  Node: silent-column-changes,  Prev: create-table-select,  Up: create-table

13.1.10.2 Silent Column Specification Changes
.............................................

In some cases, MySQL silently changes column specifications from those
given in a *Note `CREATE TABLE': create-table. or *Note `ALTER TABLE':
alter-table. statement. These might be changes to a data type, to
attributes associated with a data type, or to an index specification.

All changes are subject to the internal row-size limit of 65,535 bytes,
which may cause some attempts at data type changes to fail. See *Note
column-count-limit::.

Some silent column specification changes include modifications to
attribute or index specifications:

   * *Note `TIMESTAMP': datetime. display sizes are discarded.

     Also note that *Note `TIMESTAMP': datetime.  columns are `NOT
     NULL' by default.

   * Columns that are part of a `PRIMARY KEY' are made `NOT NULL' even
     if not declared that way.

   * Trailing spaces are automatically deleted from *Note `ENUM': enum.
     and *Note `SET': set. member values when the table is created.

   * MySQL maps certain data types used by other SQL database vendors
     to MySQL types. See *Note other-vendor-data-types::.

   * If you include a `USING' clause to specify an index type that is
     not legal for a given storage engine, but there is another index
     type available that the engine can use without affecting query
     results, the engine uses the available type.

Possible data type changes are given in the following list. If a
version number is given, the change occurs only up to the versions
listed. After that, an error occurs if a column cannot be created using
the specified data type.

   * Before MySQL 5.0.3, *Note `VARCHAR': char.  columns with a length
     less than four are changed to *Note `CHAR': char.

   * Before MySQL 5.0.3, if any column in a table has a variable
     length, the entire row becomes variable-length as a result.
     Therefore, if a table contains any variable-length columns (*Note
     `VARCHAR': char, *Note `TEXT': blob, or *Note `BLOB': blob.), all
     *Note `CHAR': char. columns longer than three characters are
     changed to *Note `VARCHAR': char. columns. This does not affect
     how you use the columns in any way; in MySQL, *Note `VARCHAR':
     char. is just a different way to store characters. MySQL performs
     this conversion because it saves space and makes table operations
     faster.  See *Note storage-engines::.

   * Before MySQL 5.0.3, a *Note `CHAR': char. or *Note `VARCHAR':
     char. column with a length specification greater than 255 is
     converted to the smallest *Note `TEXT': blob. type that can hold
     values of the given length. For example, `VARCHAR(500)' is
     converted to *Note `TEXT': blob, and `VARCHAR(200000)' is
     converted to *Note `MEDIUMTEXT': blob. Similar conversions occur
     for *Note `BINARY': binary-varbinary.  and *Note `VARBINARY':
     binary-varbinary, except that they are converted to a *Note
     `BLOB': blob.  type.

     Note that these conversions result in a change in behavior with
     regard to treatment of trailing spaces.

     As of MySQL 5.0.3, a *Note `CHAR': char. or *Note `BINARY':
     binary-varbinary. column with a length specification greater than
     255 is not silently converted.  Instead, an error occurs. From
     MySQL 5.0.6 on, silent conversion of *Note `VARCHAR': char. and
     *Note `VARBINARY': binary-varbinary. columns with a length
     specification greater than 65535 does not occur if strict SQL mode
     is enabled. Instead, an error occurs.

   * Before MySQL 5.0.10, for a specification of `DECIMAL(M,D)', if M
     is not larger than D, it is adjusted upward. For example,
     `DECIMAL(10,10)' becomes `DECIMAL(11,10)'. As of MySQL 5.0.10,
     `DECIMAL(10,10)' is created as specified.

   * Specifying the `CHARACTER SET binary' attribute for a character
     data type causes the column to be created as the corresponding
     binary data type: *Note `CHAR': char. becomes *Note `BINARY':
     binary-varbinary, *Note `VARCHAR': char. becomes *Note
     `VARBINARY': binary-varbinary, and *Note `TEXT': blob. becomes
     *Note `BLOB': blob. For the *Note `ENUM': enum. and *Note `SET':
     set. data types, this does not occur; they are created as
     declared. Suppose that you specify a table using this definition:

          CREATE TABLE t
          (
            c1 VARCHAR(10) CHARACTER SET binary,
            c2 TEXT CHARACTER SET binary,
            c3 ENUM('a','b','c') CHARACTER SET binary
          );

     The resulting table has this definition:

          CREATE TABLE t
          (
            c1 VARBINARY(10),
            c2 BLOB,
            c3 ENUM('a','b','c') CHARACTER SET binary
          );

To see whether MySQL used a data type other than the one you specified,
issue a *Note `DESCRIBE': describe. or *Note `SHOW CREATE TABLE':
show-create-table. statement after creating or altering the table.

Certain other data type changes can occur if you compress a table using
*Note `myisampack': myisampack. See *Note compressed-format::.


File: manual.info,  Node: create-trigger,  Next: create-view,  Prev: create-table,  Up: sql-syntax-data-definition

13.1.11 `CREATE TRIGGER' Syntax
-------------------------------

     CREATE
         [DEFINER = { USER | CURRENT_USER }]
         TRIGGER TRIGGER_NAME TRIGGER_TIME TRIGGER_EVENT
         ON TBL_NAME FOR EACH ROW TRIGGER_BODY

This statement creates a new trigger. A trigger is a named database
object that is associated with a table, and that activates when a
particular event occurs for the table. The trigger becomes associated
with the table named TBL_NAME, which must refer to a permanent table.
You cannot associate a trigger with a `TEMPORARY' table or a view.
*Note `CREATE TRIGGER': create-trigger. was added in MySQL 5.0.2.

In MySQL 5.0 *Note `CREATE TRIGGER': create-trigger. requires the
`SUPER' privilege.

The `DEFINER' clause determines the security context to be used when
checking access privileges at trigger activation time. It was added in
MySQL 5.0.17. See later in this section for more information.

TRIGGER_TIME is the trigger action time. It can be `BEFORE' or `AFTER'
to indicate that the trigger activates before or after each row to be
modified.

TRIGGER_EVENT indicates the kind of statement that activates the
trigger. The TRIGGER_EVENT can be one of the following:

   * *Note `INSERT': insert.: The trigger is activated whenever a new
     row is inserted into the table; for example, through *Note
     `INSERT': insert, *Note `LOAD DATA': load-data, and *Note
     `REPLACE': replace. statements.

   * *Note `UPDATE': update.: The trigger is activated whenever a row
     is modified; for example, through *Note `UPDATE': update.
     statements.

   * *Note `DELETE': delete.: The trigger is activated whenever a row
     is deleted from the table; for example, through *Note `DELETE':
     delete. and *Note `REPLACE': replace. statements. However, *Note
     `DROP TABLE': drop-table. and *Note `TRUNCATE TABLE':
     truncate-table. statements on the table do _not_ activate this
     trigger, because they do not use *Note `DELETE': delete.  See
     *Note truncate-table::.

It is important to understand that the TRIGGER_EVENT does not represent
a literal type of SQL statement that activates the trigger so much as
it represents a type of table operation. For example, an *Note
`INSERT': insert. trigger is activated by not only *Note `INSERT':
insert. statements but also *Note `LOAD DATA': load-data. statements
because both statements insert rows into a table.

A potentially confusing example of this is the `INSERT INTO ... ON
DUPLICATE KEY UPDATE ...' syntax: a `BEFORE INSERT' trigger will
activate for every row, followed by either an `AFTER INSERT' trigger or
both the `BEFORE UPDATE' and `AFTER UPDATE' triggers, depending on
whether there was a duplicate key for the row.

There cannot be two triggers for a given table that have the same
trigger action time and event. For example, you cannot have two `BEFORE
UPDATE' triggers for a table. But you can have a `BEFORE UPDATE' and a
`BEFORE INSERT' trigger, or a `BEFORE UPDATE' and an `AFTER UPDATE'
trigger.

TRIGGER_BODY is the statement to execute when the trigger activates. If
you want to execute multiple statements, use the *Note `BEGIN ... END':
begin-end.  compound statement construct. This also enables you to use
the same statements that are permissible within stored routines. See
*Note begin-end::. Some statements are not permitted in triggers; see
*Note stored-program-restrictions::.

You can refer to columns in the subject table (the table associated
with the trigger) by using the aliases `OLD' and `NEW'.  `OLD.COL_NAME'
refers to a column of an existing row before it is updated or deleted.
`NEW.COL_NAME' refers to the column of a new row to be inserted or an
existing row after it is updated.

MySQL stores the `sql_mode' system variable setting that is in effect
at the time a trigger is created, and always executes the trigger with
this setting in force, _regardless of the current server SQL mode_.

*Note*:

Currently, cascaded foreign key actions do not activate triggers.

The `DEFINER' clause specifies the MySQL account to be used when
checking access privileges at trigger activation time. If a USER value
is given, it should be a MySQL account specified as
`'USER_NAME'@'HOST_NAME'' (the same format used in the *Note `GRANT':
grant.  statement), `CURRENT_USER', or `CURRENT_USER()'. The default
`DEFINER' value is the user who executes the *Note `CREATE TRIGGER':
create-trigger. statement. This is the same as specifying `DEFINER =
CURRENT_USER' explicitly.

If you specify the `DEFINER' clause, these rules determine the legal
`DEFINER' user values:

   * If you do not have the `SUPER' privilege, the only legal USER
     value is your own account, either specified literally or by using
     `CURRENT_USER'. You cannot set the definer to some other account.

   * If you have the `SUPER' privilege, you can specify any
     syntactically legal account name. If the account does not actually
     exist, a warning is generated.

   * Although it is possible to create a trigger with a nonexistent
     `DEFINER' account, it is not a good idea for such triggers to be
     activated until the account actually does exist. Otherwise, the
     behavior with respect to privilege checking is undefined.

Note: Because MySQL currently requires the `SUPER' privilege for the
use of *Note `CREATE TRIGGER': create-trigger, only the second of the
preceding rules applies. (MySQL 5.1.6 implements the `TRIGGER'
(http://dev.mysql.com/doc/refman/5.1/en/privileges-provided.html#priv_trigger)
privilege and requires that privilege for trigger creation, so at that
point both rules come into play and `SUPER' is required only for
specifying a `DEFINER' value other than your own account.)

From MySQL 5.0.17 on, MySQL takes the `DEFINER' user into account when
checking trigger privileges as follows:

   * At *Note `CREATE TRIGGER': create-trigger. time, the user who
     issues the statement must have the `SUPER' privilege.

   * At trigger activation time, privileges are checked against the
     `DEFINER' user. This user must have these privileges:

        * The `SUPER' privilege.

        * The `SELECT' privilege for the subject table if references to
          table columns occur using `OLD.COL_NAME' or `NEW.COL_NAME' in
          the trigger definition.

        * The `UPDATE' privilege for the subject table if table columns
          are targets of `SET NEW.COL_NAME = VALUE' assignments in the
          trigger definition.

        * Whatever other privileges normally are required for the
          statements executed by the trigger.

Before MySQL 5.0.17, `DEFINER' is not available and MySQL checks
trigger privileges like this:

   * At *Note `CREATE TRIGGER': create-trigger. time, the user who
     issues the statement must have the `SUPER' privilege.

   * At trigger activation time, privileges are checked against the
     user whose actions cause the trigger to be activated. This user
     must have whatever privileges normally are required for the
     statements executed by the trigger.

For more information about trigger security, see *Note
stored-programs-security::.

Within a trigger, the `CURRENT_USER()' function returns the account
used to check privileges at trigger activation time.  Consistent with
the privilege-checking rules just given, `CURRENT_USER()' returns the
`DEFINER' user from MySQL 5.0.17 on. Before 5.0.17, `CURRENT_USER()'
returns the user whose actions caused the trigger to be activated. For
information about user auditing within triggers, see *Note
account-activity-auditing::.

If you use *Note `LOCK TABLES': lock-tables. to lock a table that has
triggers, the tables used within the trigger are also locked, as
described in *Note lock-tables-and-triggers::.

*Note*:

Before MySQL 5.0.10, triggers cannot contain direct references to
tables by name. Beginning with MySQL 5.0.10, you can write triggers
such as the one named `testref' shown in this example:

     CREATE TABLE test1(a1 INT);
     CREATE TABLE test2(a2 INT);
     CREATE TABLE test3(a3 INT NOT NULL AUTO_INCREMENT PRIMARY KEY);
     CREATE TABLE test4(
       a4 INT NOT NULL AUTO_INCREMENT PRIMARY KEY,
       b4 INT DEFAULT 0
     );

     delimiter |

     CREATE TRIGGER testref BEFORE INSERT ON test1
       FOR EACH ROW BEGIN
         INSERT INTO test2 SET a2 = NEW.a1;
         DELETE FROM test3 WHERE a3 = NEW.a1;
         UPDATE test4 SET b4 = b4 + 1 WHERE a4 = NEW.a1;
       END;
     |

     delimiter ;

     INSERT INTO test3 (a3) VALUES
       (NULL), (NULL), (NULL), (NULL), (NULL),
       (NULL), (NULL), (NULL), (NULL), (NULL);

     INSERT INTO test4 (a4) VALUES
       (0), (0), (0), (0), (0), (0), (0), (0), (0), (0);

Suppose that you insert the following values into table `test1' as
shown here:

     mysql> INSERT INTO test1 VALUES
         -> (1), (3), (1), (7), (1), (8), (4), (4);
     Query OK, 8 rows affected (0.01 sec)
     Records: 8  Duplicates: 0  Warnings: 0

As a result, the data in the four tables will be as follows:

     mysql> SELECT * FROM test1;
     +------+
     | a1   |
     +------+
     |    1 |
     |    3 |
     |    1 |
     |    7 |
     |    1 |
     |    8 |
     |    4 |
     |    4 |
     +------+
     8 rows in set (0.00 sec)

     mysql> SELECT * FROM test2;
     +------+
     | a2   |
     +------+
     |    1 |
     |    3 |
     |    1 |
     |    7 |
     |    1 |
     |    8 |
     |    4 |
     |    4 |
     +------+
     8 rows in set (0.00 sec)

     mysql> SELECT * FROM test3;
     +----+
     | a3 |
     +----+
     |  2 |
     |  5 |
     |  6 |
     |  9 |
     | 10 |
     +----+
     5 rows in set (0.00 sec)

     mysql> SELECT * FROM test4;
     +----+------+
     | a4 | b4   |
     +----+------+
     |  1 |    3 |
     |  2 |    0 |
     |  3 |    1 |
     |  4 |    2 |
     |  5 |    0 |
     |  6 |    0 |
     |  7 |    1 |
     |  8 |    1 |
     |  9 |    0 |
     | 10 |    0 |
     +----+------+
     10 rows in set (0.00 sec)


File: manual.info,  Node: create-view,  Next: drop-database,  Prev: create-trigger,  Up: sql-syntax-data-definition

13.1.12 `CREATE VIEW' Syntax
----------------------------

     CREATE
         [OR REPLACE]
         [ALGORITHM = {UNDEFINED | MERGE | TEMPTABLE}]
         [DEFINER = { USER | CURRENT_USER }]
         [SQL SECURITY { DEFINER | INVOKER }]
         VIEW VIEW_NAME [(COLUMN_LIST)]
         AS SELECT_STATEMENT
         [WITH [CASCADED | LOCAL] CHECK OPTION]

The *Note `CREATE VIEW': create-view. statement creates a new view, or
replaces an existing one if the `OR REPLACE' clause is given. This
statement was added in MySQL 5.0.1. If the view does not exist, *Note
`CREATE OR REPLACE VIEW': create-view. is the same as *Note `CREATE
VIEW': create-view. If the view does exist, *Note `CREATE OR REPLACE
VIEW': create-view. is the same as *Note `ALTER VIEW': alter-view.

The SELECT_STATEMENT is a *Note `SELECT': select. statement that
provides the definition of the view. (When you select from the view,
you select in effect using the *Note `SELECT': select.  statement.)
SELECT_STATEMENT can select from base tables or other views.

The view definition is `frozen' at creation time, so changes to the
underlying tables afterward do not affect the view definition. For
example, if a view is defined as `SELECT *' on a table, new columns
added to the table later do not become part of the view.

The `ALGORITHM' clause affects how MySQL processes the view. The
`DEFINER' and `SQL SECURITY' clauses specify the security context to be
used when checking access privileges at view invocation time. The `WITH
CHECK OPTION' clause can be given to constrain inserts or updates to
rows in tables referenced by the view. These clauses are described
later in this section.

The *Note `CREATE VIEW': create-view. statement requires the `CREATE
VIEW' privilege for the view, and some privilege for each column
selected by the *Note `SELECT': select. statement. For columns used
elsewhere in the *Note `SELECT': select. statement you must have the
`SELECT' privilege.  If the `OR REPLACE' clause is present, you must
also have the `DROP' privilege for the view. *Note `CREATE VIEW':
create-view. might also require the `SUPER' privilege, depending on the
`DEFINER' value, as described later in this section.

When a view is referenced, privilege checking occurs as described later
in this section.

A view belongs to a database. By default, a new view is created in the
default database. To create the view explicitly in a given database,
specify the name as DB_NAME.VIEW_NAME when you create it:

     mysql> CREATE VIEW test.v AS SELECT * FROM t;

Within a database, base tables and views share the same namespace, so a
base table and a view cannot have the same name.

Columns retrieved by the *Note `SELECT': select.  statement can be
simple references to table columns. They can also be expressions that
use functions, constant values, operators, and so forth.

Views must have unique column names with no duplicates, just like base
tables. By default, the names of the columns retrieved by the *Note
`SELECT': select. statement are used for the view column names. To
define explicit names for the view columns, the optional COLUMN_LIST
clause can be given as a list of comma-separated identifiers. The
number of names in COLUMN_LIST must be the same as the number of
columns retrieved by the *Note `SELECT': select. statement.

*Note*:

Prior to MySQL 5.0.72, when you modify an existing view, the server
saves a backup of the current view definition under the view database
directory, in a subdirectory named `arc'. The backup file for a view
`v' is named `v.frm-00001'.  If you alter the view again, the next
backup is named `v.frm-00002'. The three latest view backup definitions
are stored.

Backed up view definitions are not preserved by *Note `mysqldump':
mysqldump, or any other such programs, but you can retain them using a
file copy operation. However, they are not needed for anything but to
provide you with a backup of your previous view definition.

It is safe to remove these backup definitions, but only while *Note
`mysqld': mysqld. is not running. If you delete the `arc' subdirectory
or its files while *Note `mysqld': mysqld. is running, an error occurs
the next time you try to alter the view:

     mysql> ALTER VIEW v AS SELECT * FROM t;
     ERROR 6 (HY000): Error on delete of '.\test\arc/v.frm-0004' (Errcode:
     2)

Unqualified table or view names in the *Note `SELECT': select.
statement are interpreted with respect to the default database. A view
can refer to tables or views in other databases by qualifying the table
or view name with the proper database name.

A view can be created from many kinds of *Note `SELECT': select.
statements. It can refer to base tables or other views. It can use
joins, *Note `UNION': union, and subqueries. The *Note `SELECT':
select. need not even refer to any tables. The following example
defines a view that selects two columns from another table, as well as
an expression calculated from those columns:

     mysql> CREATE TABLE t (qty INT, price INT);
     mysql> INSERT INTO t VALUES(3, 50);
     mysql> CREATE VIEW v AS SELECT qty, price, qty*price AS value FROM t;
     mysql> SELECT * FROM v;
     +------+-------+-------+
     | qty  | price | value |
     +------+-------+-------+
     |    3 |    50 |   150 |
     +------+-------+-------+

A view definition is subject to the following restrictions:

   * The *Note `SELECT': select. statement cannot contain a subquery in
     the `FROM' clause.

   * The *Note `SELECT': select. statement cannot refer to system or
     user variables.

   * Within a stored program, the definition cannot refer to program
     parameters or local variables.

   * The *Note `SELECT': select. statement cannot refer to prepared
     statement parameters.

   * Any table or view referred to in the definition must exist.
     However, after a view has been created, it is possible to drop a
     table or view that the definition refers to. In this case, use of
     the view results in an error. To check a view definition for
     problems of this kind, use the *Note `CHECK TABLE': check-table.
     statement.

   * The definition cannot refer to a `TEMPORARY' table, and you cannot
     create a `TEMPORARY' view.

   * Any tables named in the view definition must exist at definition
     time.

   * You cannot associate a trigger with a view.

   * As of MySQL 5.0.52, aliases for column names in the *Note
     `SELECT': select. statement are checked against the maximum column
     length of 64 characters (not the maximum alias length of 256
     characters).

`ORDER BY' is permitted in a view definition, but it is ignored if you
select from a view using a statement that has its own `ORDER BY'.

For other options or clauses in the definition, they are added to the
options or clauses of the statement that references the view, but the
effect is undefined. For example, if a view definition includes a
`LIMIT' clause, and you select from the view using a statement that has
its own `LIMIT' clause, it is undefined which limit applies. This same
principle applies to options such as `ALL', `DISTINCT', or
`SQL_SMALL_RESULT' that follow the *Note `SELECT': select. keyword, and
to clauses such as `INTO', `FOR UPDATE', `LOCK IN SHARE MODE', and
`PROCEDURE'.

If you create a view and then change the query processing environment
by changing system variables, that may affect the results that you get
from the view:

     mysql> CREATE VIEW v (mycol) AS SELECT 'abc';
     Query OK, 0 rows affected (0.01 sec)

     mysql> SET sql_mode = '';
     Query OK, 0 rows affected (0.00 sec)

     mysql> SELECT "mycol" FROM v;
     +-------+
     | mycol |
     +-------+
     | mycol |
     +-------+
     1 row in set (0.01 sec)

     mysql> SET sql_mode = 'ANSI_QUOTES';
     Query OK, 0 rows affected (0.00 sec)

     mysql> SELECT "mycol" FROM v;
     +-------+
     | mycol |
     +-------+
     | abc   |
     +-------+
     1 row in set (0.00 sec)

The `DEFINER' and `SQL SECURITY' clauses determine which MySQL account
to use when checking access privileges for the view when a statement is
executed that references the view. These clauses were addded in MySQL
5.0.13, but have no effect until MySQL 5.0.16. The legal `SQL SECURITY'
characteristic values are `DEFINER' and `INVOKER'. These indicate that
the required privileges must be held by the user who defined or invoked
the view, respectively. The default `SQL SECURITY' value is `DEFINER'.

If a USER value is given for the `DEFINER' clause, it should be a MySQL
account specified as `'USER_NAME'@'HOST_NAME'' (the same format used in
the *Note `GRANT': grant.  statement), `CURRENT_USER', or
`CURRENT_USER()'. The default `DEFINER' value is the user who executes
the *Note `CREATE VIEW': create-view. statement. This is the same as
specifying `DEFINER = CURRENT_USER' explicitly.

If you specify the `DEFINER' clause, these rules determine the legal
`DEFINER' user values:

   * If you do not have the `SUPER' privilege, the only legal USER
     value is your own account, either specified literally or by using
     `CURRENT_USER'. You cannot set the definer to some other account.

   * If you have the `SUPER' privilege, you can specify any
     syntactically legal account name. If the account does not actually
     exist, a warning is generated.

   * Although it is possible to create a view with a nonexistent
     `DEFINER' account, an error occurs when the view is referenced if
     the `SQL SECURITY' value is `DEFINER' but the definer account does
     not exist.

For more information about view security, see *Note
stored-programs-security::.

Within a view definition, `CURRENT_USER' returns the view's `DEFINER'
value by default as of MySQL 5.0.24.  For older versions, and for views
defined with the `SQL SECURITY INVOKER' characteristic, `CURRENT_USER'
returns the account for the view's invoker. For information about user
auditing within views, see *Note account-activity-auditing::.

Within a stored routine that is defined with the `SQL SECURITY DEFINER'
characteristic, `CURRENT_USER' returns the routine's `DEFINER' value.
This also affects a view defined within such a routine, if the view
definition contains a `DEFINER' value of `CURRENT_USER'.

As of MySQL 5.0.16 (when the `DEFINER' and `SQL SECURITY' clauses were
implemented), view privileges are checked like this:

   * At view definition time, the view creator must have the privileges
     needed to use the top-level objects accessed by the view. For
     example, if the view definition refers to table columns, the
     creator must have some privilege for each column in the select
     list of the definition, and the `SELECT' privilege for each column
     used elsewhere in the definition. If the definition refers to a
     stored function, only the privileges needed to invoke the function
     can be checked. The privileges required at function invocation
     time can be checked only as it executes: For different
     invocations, different execution paths within the function might
     be taken.

   * The user who references a view must have appropriate privileges to
     access it (`SELECT' to select from it, `INSERT' to insert into it,
     and so forth.)

   * When a view has been referenced, privileges for objects accessed
     by the view are checked against the privileges held by the view
     `DEFINER' account or invoker, depending on whether the `SQL
     SECURITY' characteristic is `DEFINER' or `INVOKER', respectively.

   * If reference to a view causes execution of a stored function,
     privilege checking for statements executed within the function
     depend on whether the function `SQL SECURITY' characteristic is
     `DEFINER' or `INVOKER'. If the security characteristic is
     `DEFINER', the function runs with the privileges of the `DEFINER'
     account. If the characteristic is `INVOKER', the function runs
     with the privileges determined by the view's `SQL SECURITY'
     characteristic.

Prior to MySQL 5.0.16 (before the `DEFINER' and `SQL SECURITY' clauses
were implemented), privileges required for objects used in a view are
checked at view creation time.

Example: A view might depend on a stored function, and that function
might invoke other stored routines. For example, the following view
invokes a stored function `f()':

     CREATE VIEW v AS SELECT * FROM t WHERE t.id = f(t.name);

Suppose that `f()' contains a statement such as this:

     IF name IS NULL then
       CALL p1();
     ELSE
       CALL p2();
     END IF;

The privileges required for executing statements within `f()' need to
be checked when `f()' executes. This might mean that privileges are
needed for `p1()' or `p2()', depending on the execution path within
`f()'.  Those privileges must be checked at runtime, and the user who
must possess the privileges is determined by the `SQL SECURITY' values
of the view `v' and the function `f()'.

The `DEFINER' and `SQL SECURITY' clauses for views are extensions to
standard SQL. In standard SQL, views are handled using the rules for
`SQL SECURITY DEFINER'. The standard says that the definer of the view,
which is the same as the owner of the view's schema, gets applicable
privileges on the view (for example, `SELECT') and may grant them. MySQL
has no concept of a schema `owner', so MySQL adds a clause to identify
the definer. The `DEFINER' clause is an extension where the intent is
to have what the standard has; that is, a permanent record of who
defined the view.  This is why the default `DEFINER' value is the
account of the view creator.

If you invoke a view that was created before MySQL 5.0.13, it is
treated as though it was created with a `SQL SECURITY DEFINER'
characteristic and with a `DEFINER' value that is the same as your
account.  However, because the actual definer is unknown, MySQL issues a
warning. To eliminate the warning, it is sufficient to re-create the
view so that the view definition includes a `DEFINER' clause.

The optional `ALGORITHM' clause is a MySQL extension to standard SQL.
It affects how MySQL processes the view. `ALGORITHM' takes three values:
`MERGE', `TEMPTABLE', or `UNDEFINED'. The default algorithm is
`UNDEFINED' if no `ALGORITHM' clause is present. For more information,
see *Note view-algorithms::.

Some views are updatable. That is, you can use them in statements such
as *Note `UPDATE': update, *Note `DELETE': delete, or *Note `INSERT':
insert. to update the contents of the underlying table. For a view to
be updatable, there must be a one-to-one relationship between the rows
in the view and the rows in the underlying table. There are also
certain other constructs that make a view nonupdatable.

The `WITH CHECK OPTION' clause can be given for an updatable view to
prevent inserts or updates to rows except those for which the `WHERE'
clause in the SELECT_STATEMENT is true. The `WITH CHECK OPTION' clause
was implemented in MySQL 5.0.2.

In a `WITH CHECK OPTION' clause for an updatable view, the `LOCAL' and
`CASCADED' keywords determine the scope of check testing when the view
is defined in terms of another view. The `LOCAL' keyword restricts the
`CHECK OPTION' only to the view being defined. `CASCADED' causes the
checks for underlying views to be evaluated as well. When neither
keyword is given, the default is `CASCADED'.

For more information about updatable views and the `WITH CHECK OPTION'
clause, see *Note view-updatability::.


File: manual.info,  Node: drop-database,  Next: drop-function,  Prev: create-view,  Up: sql-syntax-data-definition

13.1.13 `DROP DATABASE' Syntax
------------------------------

     DROP {DATABASE | SCHEMA} [IF EXISTS] DB_NAME

*Note `DROP DATABASE': drop-database. drops all tables in the database
and deletes the database. Be _very_ careful with this statement! To use
*Note `DROP DATABASE': drop-database, you need the `DROP' privilege on
the database.  *Note `DROP SCHEMA': drop-database. is a synonym for
*Note `DROP DATABASE': drop-database. as of MySQL 5.0.2.

*Important*:

When a database is dropped, user privileges on the database are _not_
automatically dropped. See *Note grant::.

`IF EXISTS' is used to prevent an error from occurring if the database
does not exist.

If the default database is dropped, the default database is unset (the
`DATABASE()' function returns `NULL').

If you use *Note `DROP DATABASE': drop-database. on a symbolically
linked database, both the link and the original database are deleted.

*Note `DROP DATABASE': drop-database. returns the number of tables that
were removed. This corresponds to the number of `.frm' files removed.

The *Note `DROP DATABASE': drop-database. statement removes from the
given database directory those files and directories that MySQL itself
may create during normal operation:

   * All files with the following extensions.

     `.BAK'  `.DAT'  `.HSH'  `.MRG'
     `.MYD'  `.MYI'  `.TRG'  `.TRN'
     `.db'   `.frm'  `.ibd'  `.ndb'

   * All subdirectories with names that consist of two hex digits
     `00'-`ff'. These are subdirectories used for `RAID' tables. (These
     directories are not removed as of MySQL 5.0, when support for
     `RAID' tables was removed. You should convert any existing `RAID'
     tables and remove these directories manually before upgrading to
     MySQL 5.0. See *Note upgrading-from-previous-series::.)

   * The `db.opt' file, if it exists.

If other files or directories remain in the database directory after
MySQL removes those just listed, the database directory cannot be
removed. In this case, you must remove any remaining files or
directories manually and issue the *Note `DROP DATABASE':
drop-database. statement again.

You can also drop databases with *Note `mysqladmin': mysqladmin.  See
*Note mysqladmin::.


File: manual.info,  Node: drop-function,  Next: drop-index,  Prev: drop-database,  Up: sql-syntax-data-definition

13.1.14 `DROP FUNCTION' Syntax
------------------------------

The *Note `DROP FUNCTION': drop-function. statement is used to drop
stored functions and user-defined functions (UDFs):

   * For information about dropping stored functions, see *Note
     drop-procedure::.

   * For information about dropping user-defined functions, see *Note
     drop-function-udf::.


File: manual.info,  Node: drop-index,  Next: drop-procedure,  Prev: drop-function,  Up: sql-syntax-data-definition

13.1.15 `DROP INDEX' Syntax
---------------------------

     DROP INDEX INDEX_NAME ON TBL_NAME

*Note `DROP INDEX': drop-index. drops the index named INDEX_NAME from
the table TBL_NAME. This statement is mapped to an *Note `ALTER TABLE':
alter-table. statement to drop the index. See *Note alter-table::.

To drop a primary key, the index name is always `PRIMARY', which must
be specified as a quoted identifier because `PRIMARY' is a reserved
word:

     DROP INDEX `PRIMARY` ON t;


File: manual.info,  Node: drop-procedure,  Next: drop-table,  Prev: drop-index,  Up: sql-syntax-data-definition

13.1.16 `DROP PROCEDURE' and `DROP FUNCTION' Syntax
---------------------------------------------------

     DROP {PROCEDURE | FUNCTION} [IF EXISTS] SP_NAME

This statement is used to drop a stored procedure or function.  That
is, the specified routine is removed from the server. As of MySQL
5.0.3, you must have the `ALTER ROUTINE' privilege for the routine. (If
the `automatic_sp_privileges' system variable is enabled, that
privilege and `EXECUTE' are granted automatically to the routine
creator when the routine is created and dropped from the creator when
the routine is dropped. See *Note stored-routines-privileges::.)

The `IF EXISTS' clause is a MySQL extension. It prevents an error from
occurring if the procedure or function does not exist. A warning is
produced that can be viewed with *Note `SHOW WARNINGS': show-warnings.

*Note*:

`DROP PROCEDURE IF EXISTS' and `DROP FUNCTION IF EXISTS' are not
written to the binary log (and thus not replicated) if the stored
procedure or function named in the `DROP' statement does not exist on
the master. This is a known issue, which is resolved in MySQL 5.1 and
later. (Bug #13684)

*Note `DROP FUNCTION': drop-function. is also used to drop user-defined
functions (see *Note drop-function-udf::).


File: manual.info,  Node: drop-table,  Next: drop-trigger,  Prev: drop-procedure,  Up: sql-syntax-data-definition

13.1.17 `DROP TABLE' Syntax
---------------------------

     DROP [TEMPORARY] TABLE [IF EXISTS]
         TBL_NAME [, TBL_NAME] ...
         [RESTRICT | CASCADE]

*Note `DROP TABLE': drop-table. removes one or more tables. You must
have the `DROP' privilege for each table. All table data and the table
definition are _removed_, so _be careful_ with this statement! If any
of the tables named in the argument list do not exist, MySQL returns an
error indicating by name which nonexisting tables it was unable to drop,
but it also drops all of the tables in the list that do exist.

*Important*:

When a table is dropped, user privileges on the table are _not_
automatically dropped. See *Note grant::.

Use `IF EXISTS' to prevent an error from occurring for tables that do
not exist. A `NOTE' is generated for each nonexistent table when using
`IF EXISTS'. See *Note show-warnings::.

`RESTRICT' and `CASCADE' are permitted to make porting easier. In MySQL
5.0, they do nothing.

*Note*:

*Note `DROP TABLE': drop-table. automatically commits the current
active transaction, unless you use the `TEMPORARY' keyword.

The `TEMPORARY' keyword has the following effects:

   * The statement drops only `TEMPORARY' tables.

   * The statement does not end an ongoing transaction.

   * No access rights are checked. (A `TEMPORARY' table is visible only
     to the session that created it, so no check is necessary.)

Using `TEMPORARY' is a good way to ensure that you do not accidentally
drop a non-`TEMPORARY' table.


File: manual.info,  Node: drop-trigger,  Next: drop-view,  Prev: drop-table,  Up: sql-syntax-data-definition

13.1.18 `DROP TRIGGER' Syntax
-----------------------------

     DROP TRIGGER [IF EXISTS] [SCHEMA_NAME.]TRIGGER_NAME

This statement drops a trigger. The schema (database) name is optional.
If the schema is omitted, the trigger is dropped from the default
schema. *Note `DROP TRIGGER': drop-trigger.  was added in MySQL 5.0.2.
Its use requires the `SUPER' privilege.

Use `IF EXISTS' to prevent an error from occurring for a trigger that
does not exist. A `NOTE' is generated for a nonexistent trigger when
using `IF EXISTS'. See *Note show-warnings::. The `IF EXISTS' clause
was added in MySQL 5.0.32.

Triggers for a table are also dropped if you drop the table.

*Note*:

Prior to MySQL 5.0.10, the table name was required instead of the
schema name (`TABLE_NAME.TRIGGER_NAME').  When upgrading from a
previous version of MySQL 5.0 to MySQL 5.0.10 or newer, you must drop
all triggers and re-create them.  Otherwise, *Note `DROP TRIGGER':
drop-trigger. does not work for older triggers after the upgrade. See
*Note upgrading-from-previous-series::, for a suggested upgrade
procedure.

In addition, triggers created in MySQL 5.0.16 or later cannot be
dropped following a downgrade to MySQL 5.0.15 or earlier. If you wish
to perform such a downgrade, you must also in this case drop all
triggers _prior to_ the downgrade, and then re-create them afterward.

(For more information about these two issues, see Bug #15921 and Bug
#18588.)


File: manual.info,  Node: drop-view,  Next: rename-table,  Prev: drop-trigger,  Up: sql-syntax-data-definition

13.1.19 `DROP VIEW' Syntax
--------------------------

     DROP VIEW [IF EXISTS]
         VIEW_NAME [, VIEW_NAME] ...
         [RESTRICT | CASCADE]

*Note `DROP VIEW': drop-view. removes one or more views. You must have
the `DROP' privilege for each view. If any of the views named in the
argument list do not exist, MySQL returns an error indicating by name
which nonexisting views it was unable to drop, but it also drops all of
the views in the list that do exist.

The `IF EXISTS' clause prevents an error from occurring for views that
don't exist. When this clause is given, a `NOTE' is generated for each
nonexistent view.  See *Note show-warnings::.

`RESTRICT' and `CASCADE', if given, are parsed and ignored.

This statement was added in MySQL 5.0.1.


File: manual.info,  Node: rename-table,  Next: truncate-table,  Prev: drop-view,  Up: sql-syntax-data-definition

13.1.20 `RENAME TABLE' Syntax
-----------------------------

     RENAME TABLE TBL_NAME TO NEW_TBL_NAME
         [, TBL_NAME2 TO NEW_TBL_NAME2] ...

This statement renames one or more tables.

The rename operation is done atomically, which means that no other
session can access any of the tables while the rename is running.  For
example, if you have an existing table `old_table', you can create
another table `new_table' that has the same structure but is empty, and
then replace the existing table with the empty one as follows (assuming
that `backup_table' does not already exist):

     CREATE TABLE new_table (...);
     RENAME TABLE old_table TO backup_table, new_table TO old_table;

If the statement renames more than one table, renaming operations are
done from left to right. If you want to swap two table names, you can
do so like this (assuming that `tmp_table' does not already exist):

     RENAME TABLE old_table TO tmp_table,
                  new_table TO old_table,
                  tmp_table TO new_table;

As long as two databases are on the same file system, you can use *Note
`RENAME TABLE': rename-table. to move a table from one database to
another:

     RENAME TABLE CURRENT_DB.TBL_NAME TO OTHER_DB.TBL_NAME;

Beginning with MySQL 5.0.2, if there are any triggers associated with a
table which is moved to a different database using *Note `RENAME
TABLE': rename-table, then the statement fails with the error `Trigger
in wrong schema'.

As of MySQL 5.0.14, *Note `RENAME TABLE': rename-table.  also works for
views, as long as you do not try to rename a view into a different
database.

Any privileges granted specifically for the renamed table or view are
not migrated to the new name. They must be changed manually.

When you execute `RENAME', you cannot have any locked tables or active
transactions. You must also have the `ALTER' and `DROP' privileges on
the original table, and the `CREATE' and `INSERT' privileges on the new
table.

If MySQL encounters any errors in a multiple-table rename, it does a
reverse rename for all renamed tables to return everything to its
original state.

You cannot use `RENAME' to rename a `TEMPORARY' table. However, you can
use *Note `ALTER TABLE': alter-table. instead:

     mysql> ALTER TABLE orig_name RENAME new_name;


File: manual.info,  Node: truncate-table,  Prev: rename-table,  Up: sql-syntax-data-definition

13.1.21 `TRUNCATE TABLE' Syntax
-------------------------------

     TRUNCATE [TABLE] TBL_NAME

*Note `TRUNCATE TABLE': truncate-table. empties a table completely.
Logically, this is equivalent to a *Note `DELETE': delete. statement
that deletes all rows, but there are practical differences under some
circumstances.

For an `InnoDB' table before version 5.0.3, `InnoDB' processes *Note
`TRUNCATE TABLE': truncate-table. by deleting rows one by one. As of
MySQL 5.0.3, row by row deletion is used only if there are any `FOREIGN
KEY' constraints that reference the table. If there are no `FOREIGN
KEY' constraints, `InnoDB' performs fast truncation by dropping the
original table and creating an empty one with the same definition,
which is much faster than deleting rows one by one. (When fast
truncation is used, it resets any `AUTO_INCREMENT' counter to zero.
From MySQL 5.0.13 on, the `AUTO_INCREMENT' counter is reset to zero by
*Note `TRUNCATE TABLE': truncate-table, regardless of whether there is
a foreign key constraint.)

In the case that `FOREIGN KEY' constraints reference the table,
`InnoDB' deletes rows one by one and processes the constraints on each
one. If the `FOREIGN KEY' constraint specifies `DELETE CASCADE', rows
from the child (referenced) table are deleted, and the truncated table
becomes empty. If the `FOREIGN KEY' constraint does _not_ specify
`CASCADE', the *Note `TRUNCATE TABLE': truncate-table. statement deletes
rows one by one and stops if it encounters a parent row that is
referenced by the child, returning this error:

     ERROR 1451 (23000): Cannot delete or update a parent row: a foreign
     key constraint fails (`test`.`child`, CONSTRAINT `child_ibfk_1`
     FOREIGN KEY (`parent_id`) REFERENCES `parent` (`id`))

This is the same as a *Note `DELETE': delete.  statement with no
`WHERE' clause.

The count of rows affected by *Note `TRUNCATE TABLE': truncate-table.
is accurate only when it is mapped to a *Note `DELETE': delete.
statement.

For other storage engines, *Note `TRUNCATE TABLE': truncate-table.
differs from *Note `DELETE': delete.  in the following ways in MySQL
5.0:

   * Truncate operations drop and re-create the table, which is much
     faster than deleting rows one by one, particularly for large
     tables.

   * As of MySQL 5.0.8, truncate operations cause an implicit commit.
     Before 5.0.8, truncate operations are not transaction-safe; an
     error occurs when attempting one in the course of an active
     transaction.

   * Truncation operations cannot be performed if the session holds an
     active table lock.

   * Truncation operations do not return a meaningful value for the
     number of deleted rows. The usual result is `0 rows affected,'
     which should be interpreted as `no information.'

   * As long as the table format file `TBL_NAME.frm' is valid, the
     table can be re-created as an empty table with *Note `TRUNCATE
     TABLE': truncate-table, even if the data or index files have
     become corrupted.

   * The table handler does not remember the last used `AUTO_INCREMENT'
     value, but starts counting from the beginning. This is true even
     for `MyISAM' and `InnoDB', which normally do not reuse sequence
     values.

   * Since truncation of a table does not make any use of *Note
     `DELETE': delete, the *Note `TRUNCATE TABLE': truncate-table.
     statement does not invoke `ON DELETE' triggers.


File: manual.info,  Node: sql-syntax-data-manipulation,  Next: sql-syntax-transactions,  Prev: sql-syntax-data-definition,  Up: sql-syntax

13.2 Data Manipulation Statements
=================================

* Menu:

* call::                         `CALL' Syntax
* delete::                       `DELETE' Syntax
* do::                           `DO' Syntax
* handler::                      `HANDLER' Syntax
* insert::                       `INSERT' Syntax
* load-data::                    `LOAD DATA INFILE' Syntax
* replace::                      `REPLACE' Syntax
* select::                       `SELECT' Syntax
* subqueries::                   Subquery Syntax
* update::                       `UPDATE' Syntax


File: manual.info,  Node: call,  Next: delete,  Prev: sql-syntax-data-manipulation,  Up: sql-syntax-data-manipulation

13.2.1 `CALL' Syntax
--------------------

     CALL SP_NAME([PARAMETER[,...]])
     CALL SP_NAME[()]

The *Note `CALL': call. statement invokes a stored procedure that was
defined previously with *Note `CREATE PROCEDURE': create-procedure.

As of MySQL 5.0.30, stored procedures that take no arguments can be
invoked without parentheses. That is, `CALL p()' and `CALL p' are
equivalent.

*Note `CALL': call. can pass back values to its caller using parameters
that are declared as `OUT' or `INOUT' parameters.  When the procedure
returns, a client program can also obtain the number of rows affected
for the final statement executed within the routine: At the SQL level,
call the `ROW_COUNT()' function; from the C API, call the *Note
`mysql_affected_rows()': mysql-affected-rows. function.

To get back a value from a procedure using an `OUT' or `INOUT'
parameter, pass the parameter by means of a user variable, and then
check the value of the variable after the procedure returns. (If you are
calling the procedure from within another stored procedure or function,
you can also pass a routine parameter or local routine variable as an
`IN' or `INOUT' parameter.) For an `INOUT' parameter, initialize its
value before passing it to the procedure. The following procedure has
an `OUT' parameter that the procedure sets to the current server
version, and an `INOUT' value that the procedure increments by one from
its current value:

     CREATE PROCEDURE p (OUT ver_param VARCHAR(25), INOUT incr_param INT)
     BEGIN
       # Set value of OUT parameter
       SELECT VERSION() INTO ver_param;
       # Increment value of INOUT parameter
       SET incr_param = incr_param + 1;
     END;

Before calling the procedure, initialize the variable to be passed as
the `INOUT' parameter. After calling the procedure, the values of the
two variables will have been set or modified:

     mysql> SET @increment = 10;
     mysql> CALL p(@version, @increment);
     mysql> SELECT @version, @increment;
     +------------+------------+
     | @version   | @increment |
     +------------+------------+
     | 5.0.25-log | 11         |
     +------------+------------+

In prepared *Note `CALL': call. statements used with *Note `PREPARE':
prepare. and *Note `EXECUTE': execute, placeholder support is available
in MySQL 5.0 for `IN' parameters, but not for `OUT' or `INOUT'
parameters. To work around this limitation for `OUT' and `INOUT'
parameters, to forgo the use of placeholders: Refer to user variables
in the *Note `CALL': call. statement itself and do not specify them in
the *Note `EXECUTE': execute. statement:

     mysql> SET @increment = 10;
     mysql> PREPARE s FROM 'CALL p(@version, @increment)';
     mysql> EXECUTE s;
     mysql> SELECT @version, @increment;
     +-----------------+------------+
     | @version        | @increment |
     +-----------------+------------+
     | 6.0.7-alpha-log | 11         |
     +-----------------+------------+

To write C programs that use the *Note `CALL': call. SQL statement to
execute stored procedures that produce result sets, the
`CLIENT_MULTI_RESULTS' flag must be enabled. This is because each *Note
`CALL': call. returns a result to indicate the call status, in addition
to any result sets that might be returned by statements executed within
the procedure. `CLIENT_MULTI_RESULTS' must also be enabled if *Note
`CALL': call. is used to execute any stored procedure that contains
prepared statements. It cannot be determined when such a procedure is
loaded whether those statements will produce result sets, so it is
necessary to assume that they will.

`CLIENT_MULTI_RESULTS' can be enabled when you call *Note
`mysql_real_connect()': mysql-real-connect, either explicitly by
passing the `CLIENT_MULTI_RESULTS' flag itself, or implicitly by passing
`CLIENT_MULTI_STATEMENTS' (which also enables `CLIENT_MULTI_RESULTS').

To process the result of a *Note `CALL': call.  statement executed using
*Note `mysql_query()': mysql-query. or *Note `mysql_real_query()':
mysql-real-query, use a loop that calls *Note `mysql_next_result()':
mysql-next-result. to determine whether there are more results. For an
example, see *Note c-api-multiple-queries::.

For programs written in a language that provides a MySQL interface,
there is no native method for directly retrieving the results of `OUT'
or `INOUT' parameters from *Note `CALL': call. statements. To get the
parameter values, pass user-defined variables to the procedure in the
*Note `CALL': call. statement and then execute a *Note `SELECT':
select. statement to produce a result set containing the variable
values. To handle an `INOUT' parameter, execute a statement prior to
the *Note `CALL': call. that sets the corresponding user variable to
the value to be passed to the procedure.

The following example illustrates the technique (without error
checking) for the stored procedure `p' described earlier that has an
`OUT' parameter and an `INOUT' parameter:

     mysql_query(mysql, "SET @increment = 10");
     mysql_query(mysql, "CALL p(@version, @increment)");
     mysql_query(mysql, "SELECT @version, @increment");
     result = mysql_store_result(mysql);
     row = mysql_fetch_row(result);
     mysql_free_result(result);

After the preceding code executes, `row[0]' and `row[1]' contain the
values of `@version' and `@increment', respectively.


File: manual.info,  Node: delete,  Next: do,  Prev: call,  Up: sql-syntax-data-manipulation

13.2.2 `DELETE' Syntax
----------------------

Single-table syntax:

     DELETE [LOW_PRIORITY] [QUICK] [IGNORE] FROM TBL_NAME
         [WHERE WHERE_CONDITION]
         [ORDER BY ...]
         [LIMIT ROW_COUNT]

Multiple-table syntax:

     DELETE [LOW_PRIORITY] [QUICK] [IGNORE]
         TBL_NAME[.*] [, TBL_NAME[.*]] ...
         FROM TABLE_REFERENCES
         [WHERE WHERE_CONDITION]

Or:

     DELETE [LOW_PRIORITY] [QUICK] [IGNORE]
         FROM TBL_NAME[.*] [, TBL_NAME[.*]] ...
         USING TABLE_REFERENCES
         [WHERE WHERE_CONDITION]

For the single-table syntax, the *Note `DELETE': delete. statement
deletes rows from TBL_NAME and returns a count of the number of deleted
rows. This count can be obtained by calling the `ROW_COUNT()' function
(see *Note information-functions::). The `WHERE' clause, if given,
specifies the conditions that identify which rows to delete. With no
`WHERE' clause, all rows are deleted. If the `ORDER BY' clause is
specified, the rows are deleted in the order that is specified. The
`LIMIT' clause places a limit on the number of rows that can be deleted.

For the multiple-table syntax, *Note `DELETE': delete. deletes from each
TBL_NAME the rows that satisfy the conditions. In this case, `ORDER BY'
and `LIMIT' cannot be used.

WHERE_CONDITION is an expression that evaluates to true for each row to
be deleted. It is specified as described in *Note select::.

Currently, you cannot delete from a table and select from the same
table in a subquery.

You need the `DELETE' privilege on a table to delete rows from it. You
need only the `SELECT' privilege for any columns that are only read,
such as those named in the `WHERE' clause.

As stated, a *Note `DELETE': delete. statement with no `WHERE' clause
deletes all rows. A faster way to do this, when you do not need to know
the number of deleted rows, is to use *Note `TRUNCATE TABLE':
truncate-table.  However, within a transaction or if you have a lock on
the table, *Note `TRUNCATE TABLE': truncate-table. cannot be used
whereas *Note `DELETE': delete. can. See *Note truncate-table::, and
*Note lock-tables::.

If you delete the row containing the maximum value for an
`AUTO_INCREMENT' column, the value is reused later for a `BDB' table,
but not for a `MyISAM' or `InnoDB' table. If you delete all rows in the
table with `DELETE FROM TBL_NAME' (without a `WHERE' clause) in
`autocommit' mode, the sequence starts over for all storage engines
except `InnoDB' and `MyISAM'. There are some exceptions to this
behavior for `InnoDB' tables, as discussed in *Note
innodb-auto-increment-handling::.

For `MyISAM' and `BDB' tables, you can specify an `AUTO_INCREMENT'
secondary column in a multiple-column key. In this case, reuse of values
deleted from the top of the sequence occurs even for `MyISAM' tables.
See *Note example-auto-increment::.

The *Note `DELETE': delete. statement supports the following modifiers:

   * If you specify `LOW_PRIORITY', the server delays execution of the
     *Note `DELETE': delete.  until no other clients are reading from
     the table. This affects only storage engines that use only
     table-level locking (such as `MyISAM', `MEMORY', and `MERGE').

   * For `MyISAM' tables, if you use the `QUICK' keyword, the storage
     engine does not merge index leaves during delete, which may speed
     up some kinds of delete operations.

   * The `IGNORE' keyword causes MySQL to ignore all errors during the
     process of deleting rows. (Errors encountered during the parsing
     stage are processed in the usual manner.) Errors that are ignored
     due to the use of `IGNORE' are returned as warnings.

The speed of delete operations may also be affected by factors
discussed in *Note delete-speed::.

In `MyISAM' tables, deleted rows are maintained in a linked list and
subsequent *Note `INSERT': insert. operations reuse old row positions.
To reclaim unused space and reduce file sizes, use the *Note `OPTIMIZE
TABLE': optimize-table. statement or the *Note `myisamchk': myisamchk.
utility to reorganize tables.  *Note `OPTIMIZE TABLE': optimize-table.
is easier to use, but *Note `myisamchk': myisamchk. is faster. See
*Note optimize-table::, and *Note myisamchk::.

The `QUICK' modifier affects whether index leaves are merged for delete
operations. `DELETE QUICK' is most useful for applications where index
values for deleted rows are replaced by similar index values from rows
inserted later. In this case, the holes left by deleted values are
reused.

`DELETE QUICK' is not useful when deleted values lead to underfilled
index blocks spanning a range of index values for which new inserts
occur again. In this case, use of `QUICK' can lead to wasted space in
the index that remains unreclaimed. Here is an example of such a
scenario:

  1. Create a table that contains an indexed `AUTO_INCREMENT' column.

  2. Insert many rows into the table. Each insert results in an index
     value that is added to the high end of the index.

  3. Delete a block of rows at the low end of the column range using
     `DELETE QUICK'.

In this scenario, the index blocks associated with the deleted index
values become underfilled but are not merged with other index blocks
due to the use of `QUICK'. They remain underfilled when new inserts
occur, because new rows do not have index values in the deleted range.
Furthermore, they remain underfilled even if you later use *Note
`DELETE': delete. without `QUICK', unless some of the deleted index
values happen to lie in index blocks within or adjacent to the
underfilled blocks. To reclaim unused index space under these
circumstances, use *Note `OPTIMIZE TABLE': optimize-table.

If you are going to delete many rows from a table, it might be faster
to use `DELETE QUICK' followed by *Note `OPTIMIZE TABLE':
optimize-table. This rebuilds the index rather than performing many
index block merge operations.

The MySQL-specific `LIMIT ROW_COUNT' option to *Note `DELETE': delete.
tells the server the maximum number of rows to be deleted before
control is returned to the client. This can be used to ensure that a
given *Note `DELETE': delete. statement does not take too much time.
You can simply repeat the *Note `DELETE': delete. statement until the
number of affected rows is less than the `LIMIT' value.

If the *Note `DELETE': delete. statement includes an `ORDER BY' clause,
rows are deleted in the order specified by the clause. This is useful
primarily in conjunction with `LIMIT'. For example, the following
statement finds rows matching the `WHERE' clause, sorts them by
`timestamp_column', and deletes the first (oldest) one:

     DELETE FROM somelog WHERE user = 'jcole'
     ORDER BY timestamp_column LIMIT 1;

`ORDER BY' may also be useful in some cases to delete rows in an order
required to avoid referential integrity violations.

If you are deleting many rows from a large table, you may exceed the
lock table size for an `InnoDB' table. To avoid this problem, or simply
to minimize the time that the table remains locked, the following
strategy (which does not use *Note `DELETE': delete. at all) might be
helpful:

  1. Select the rows _not_ to be deleted into an empty table that has
     the same structure as the original table:

          INSERT INTO t_copy SELECT * FROM t WHERE ... ;

  2. Use *Note `RENAME TABLE': rename-table. to atomically move the
     original table out of the way and rename the copy to the original
     name:

          RENAME TABLE t TO t_old, t_copy TO t;

  3. Drop the original table:

          DROP TABLE t_old;

No other sessions can access the tables involved while *Note `RENAME
TABLE': rename-table. executes, so the rename operation is not subject
to concurrency problems. See *Note rename-table::.

You can specify multiple tables in a *Note `DELETE': delete. statement
to delete rows from one or more tables depending on the particular
condition in the `WHERE' clause. However, you cannot use `ORDER BY' or
`LIMIT' in a multiple-table *Note `DELETE': delete. The
TABLE_REFERENCES clause lists the tables involved in the join. Its
syntax is described in *Note join::.

For the first multiple-table syntax, only matching rows from the tables
listed before the `FROM' clause are deleted. For the second
multiple-table syntax, only matching rows from the tables listed in the
`FROM' clause (before the `USING' clause) are deleted. The effect is
that you can delete rows from many tables at the same time and have
additional tables that are used only for searching:

     DELETE t1, t2 FROM t1 INNER JOIN t2 INNER JOIN t3
     WHERE t1.id=t2.id AND t2.id=t3.id;

Or:

     DELETE FROM t1, t2 USING t1 INNER JOIN t2 INNER JOIN t3
     WHERE t1.id=t2.id AND t2.id=t3.id;

These statements use all three tables when searching for rows to
delete, but delete matching rows only from tables `t1' and `t2'.

The preceding examples use `INNER JOIN', but multiple-table *Note
`DELETE': delete. statements can use other types of join permitted in
*Note `SELECT': select. statements, such as `LEFT JOIN'. For example,
to delete rows that exist in `t1' that have no match in `t2', use a
`LEFT JOIN':

     DELETE t1 FROM t1 LEFT JOIN t2 ON t1.id=t2.id WHERE t2.id IS NULL;

The syntax permits `.*' after each TBL_NAME for compatibility with
`Access'.

If you use a multiple-table *Note `DELETE': delete.  statement
involving `InnoDB' tables for which there are foreign key constraints,
the MySQL optimizer might process tables in an order that differs from
that of their parent/child relationship. In this case, the statement
fails and rolls back. Instead, you should delete from a single table and
rely on the `ON DELETE' capabilities that `InnoDB' provides to cause
the other tables to be modified accordingly.

*Note*:

If you declare an alias for a table, you must use the alias when
referring to the table:

     DELETE t1 FROM test AS t1, test2 WHERE ...

Table aliases in a multiple-table *Note `DELETE': delete. should be
declared only in the TABLE_REFERENCES part of the statement.
Declaration of aliases other than in the TABLE_REFERENCES part should
be avoided because that can lead to ambiguous statements that have
unexpected results such as deleting rows from the wrong table. This is
such a statement:

     DELETE t1 AS a2 FROM t1 AS a1 INNER JOIN t2 AS a2;

For alias references in the list of tables from which to delete rows in
a multiple-table delete, the default database is used unless one is
specified explicitly. For example, if the default database is `db1',
the following statement does not work because the unqualified alias
reference `a2' is interpreted as having a database of `db1':

     DELETE a1, a2 FROM db1.t1 AS a1 INNER JOIN db2.t2 AS a2
     WHERE a1.id=a2.id;

To correctly match an alias that refers to a table outside the default
database, you must explicitly qualify the reference with the name of
the proper database:

     DELETE a1, db2.a2 FROM db1.t1 AS a1 INNER JOIN db2.t2 AS a2
     WHERE a1.id=a2.id;


File: manual.info,  Node: do,  Next: handler,  Prev: delete,  Up: sql-syntax-data-manipulation

13.2.3 `DO' Syntax
------------------

     DO EXPR [, EXPR] ...

*Note `DO': do. executes the expressions but does not return any
results. In most respects, *Note `DO': do. is shorthand for `SELECT
EXPR, ...', but has the advantage that it is slightly faster when you
do not care about the result.

*Note `DO': do. is useful primarily with functions that have side
effects, such as `RELEASE_LOCK()'.


File: manual.info,  Node: handler,  Next: insert,  Prev: do,  Up: sql-syntax-data-manipulation

13.2.4 `HANDLER' Syntax
-----------------------

     HANDLER TBL_NAME OPEN [ [AS] ALIAS]

     HANDLER TBL_NAME READ INDEX_NAME { = | <= | >= | < | > } (VALUE1,VALUE2,...)
         [ WHERE WHERE_CONDITION ] [LIMIT ... ]
     HANDLER TBL_NAME READ INDEX_NAME { FIRST | NEXT | PREV | LAST }
         [ WHERE WHERE_CONDITION ] [LIMIT ... ]
     HANDLER TBL_NAME READ { FIRST | NEXT }
         [ WHERE WHERE_CONDITION ] [LIMIT ... ]

     HANDLER TBL_NAME CLOSE

The *Note `HANDLER': handler. statement provides direct access to table
storage engine interfaces. It is available for `MyISAM' and `InnoDB'
tables.

The `HANDLER ... OPEN' statement opens a table, making it accessible
using subsequent `HANDLER ...  READ' statements. This table object is
not shared by other sessions and is not closed until the session calls
`HANDLER ... CLOSE' or the session terminates. If you open the table
using an alias, further references to the open table with other *Note
`HANDLER': handler. statements must use the alias rather than the table
name.

The first `HANDLER ... READ' syntax fetches a row where the index
specified satisfies the given values and the `WHERE' condition is met.
If you have a multiple-column index, specify the index column values as
a comma-separated list. Either specify values for all the columns in
the index, or specify values for a leftmost prefix of the index
columns. Suppose that an index `my_idx' includes three columns named
`col_a', `col_b', and `col_c', in that order. The *Note `HANDLER':
handler. statement can specify values for all three columns in the
index, or for the columns in a leftmost prefix. For example:

     HANDLER ... READ my_idx = (col_a_val,col_b_val,col_c_val) ...
     HANDLER ... READ my_idx = (col_a_val,col_b_val) ...
     HANDLER ... READ my_idx = (col_a_val) ...

To employ the *Note `HANDLER': handler. interface to refer to a table's
`PRIMARY KEY', use the quoted identifier ``PRIMARY`':

     HANDLER TBL_NAME READ `PRIMARY` ...

The second `HANDLER ... READ' syntax fetches a row from the table in
index order that matches the `WHERE' condition.

The third `HANDLER ... READ' syntax fetches a row from the table in
natural row order that matches the `WHERE' condition. It is faster than
`HANDLER TBL_NAME READ INDEX_NAME' when a full table scan is desired.
Natural row order is the order in which rows are stored in a `MyISAM'
table data file. This statement works for `InnoDB' tables as well, but
there is no such concept because there is no separate data file.

Without a `LIMIT' clause, all forms of `HANDLER ... READ' fetch a
single row if one is available. To return a specific number of rows,
include a `LIMIT' clause. It has the same syntax as for the *Note
`SELECT': select. statement. See *Note select::.

`HANDLER ... CLOSE' closes a table that was opened with `HANDLER ...
OPEN'.

There are several reasons to use the *Note `HANDLER': handler.
interface instead of normal *Note `SELECT': select. statements:

   * *Note `HANDLER': handler. is faster than *Note `SELECT': select.:

        * A designated storage engine handler object is allocated for
          the `HANDLER ... OPEN'. The object is reused for subsequent
          *Note `HANDLER': handler. statements for that table; it need
          not be reinitialized for each one.

        * There is less parsing involved.

        * There is no optimizer or query-checking overhead.

        * The table does not have to be locked between two handler
          requests.

        * The handler interface does not have to provide a consistent
          look of the data (for example, dirty reads are permitted), so
          the storage engine can use optimizations that *Note `SELECT':
          select. does not normally permit.

   * For applications that use a low-level `ISAM'-like interface, *Note
     `HANDLER': handler. makes it much easier to port them to MySQL.

   * *Note `HANDLER': handler. enables you to traverse a database in a
     manner that is difficult (or even impossible) to accomplish with
     *Note `SELECT': select. The *Note `HANDLER': handler. interface is
     a more natural way to look at data when working with applications
     that provide an interactive user interface to the database.

*Note `HANDLER': handler. is a somewhat low-level statement. For
example, it does not provide consistency. That is, `HANDLER ... OPEN'
does _not_ take a snapshot of the table, and does _not_ lock the table.
This means that after a `HANDLER ...  OPEN' statement is issued, table
data can be modified (by the current session or other sessions) and
these modifications might be only partially visible to `HANDLER ...
NEXT' or `HANDLER ... PREV' scans.

An open handler can be closed and marked for reopen, in which case the
handler loses its position in the table. This occurs when both of the
following circumstances are true:

   * Any session executes *Note `FLUSH TABLES': flush.  or DDL
     statements on the handler's table.

   * The session in which the handler is open executes non-*Note
     `HANDLER': handler. statements that use tables.


File: manual.info,  Node: insert,  Next: load-data,  Prev: handler,  Up: sql-syntax-data-manipulation

13.2.5 `INSERT' Syntax
----------------------

* Menu:

* insert-select::                `INSERT ... SELECT' Syntax
* insert-delayed::               `INSERT DELAYED' Syntax
* insert-on-duplicate::          `INSERT ... ON DUPLICATE KEY UPDATE' Syntax

     INSERT [LOW_PRIORITY | DELAYED | HIGH_PRIORITY] [IGNORE]
         [INTO] TBL_NAME [(COL_NAME,...)]
         {VALUES | VALUE} ({EXPR | DEFAULT},...),(...),...
         [ ON DUPLICATE KEY UPDATE
           COL_NAME=EXPR
             [, COL_NAME=EXPR] ... ]

Or:

     INSERT [LOW_PRIORITY | DELAYED | HIGH_PRIORITY] [IGNORE]
         [INTO] TBL_NAME
         SET COL_NAME={EXPR | DEFAULT}, ...
         [ ON DUPLICATE KEY UPDATE
           COL_NAME=EXPR
             [, COL_NAME=EXPR] ... ]

Or:

     INSERT [LOW_PRIORITY | HIGH_PRIORITY] [IGNORE]
         [INTO] TBL_NAME [(COL_NAME,...)]
         SELECT ...
         [ ON DUPLICATE KEY UPDATE
           COL_NAME=EXPR
             [, COL_NAME=EXPR] ... ]

*Note `INSERT': insert. inserts new rows into an existing table. The
*Note `INSERT ... VALUES': insert. and *Note `INSERT ... SET': insert.
forms of the statement insert rows based on explicitly specified
values. The *Note `INSERT ... SELECT': insert-select. form inserts rows
selected from another table or tables. *Note `INSERT ... SELECT':
insert-select. is discussed further in *Note insert-select::.

You can use *Note `REPLACE': replace. instead of *Note `INSERT':
insert. to overwrite old rows.  *Note `REPLACE': replace. is the
counterpart to *Note `INSERT IGNORE': insert. in the treatment of new
rows that contain unique key values that duplicate old rows: The new
rows are used to replace the old rows rather than being discarded. See
*Note replace::.

TBL_NAME is the table into which rows should be inserted. The columns
for which the statement provides values can be specified as follows:

   * You can provide a comma-separated list of column names following
     the table name. In this case, a value for each named column must
     be provided by the `VALUES' list or the *Note `SELECT': select.
     statement.

   * If you do not specify a list of column names for *Note `INSERT ...
     VALUES': insert. or *Note `INSERT ... SELECT': insert-select,
     values for every column in the table must be provided by the
     `VALUES' list or the *Note `SELECT': select. statement. If you do
     not know the order of the columns in the table, use `DESCRIBE
     TBL_NAME' to find out.

   * The `SET' clause indicates the column names explicitly.

Column values can be given in several ways:

   * If you are not running in strict SQL mode, any column not
     explicitly given a value is set to its default (explicit or
     implicit) value. For example, if you specify a column list that
     does not name all the columns in the table, unnamed columns are
     set to their default values. Default value assignment is described
     in *Note data-type-defaults::. See also *Note
     constraint-invalid-data::.

     If you want an *Note `INSERT': insert. statement to generate an
     error unless you explicitly specify values for all columns that do
     not have a default value, you should use strict mode. See *Note
     server-sql-mode::.

   * Use the keyword `DEFAULT' to set a column explicitly to its
     default value. This makes it easier to write *Note `INSERT':
     insert. statements that assign values to all but a few columns,
     because it enables you to avoid writing an incomplete `VALUES' list
     that does not include a value for each column in the table.
     Otherwise, you would have to write out the list of column names
     corresponding to each value in the `VALUES' list.

     You can also use `DEFAULT(COL_NAME)' as a more general form that
     can be used in expressions to produce a given column's default
     value.

   * If both the column list and the `VALUES' list are empty, *Note
     `INSERT': insert. creates a row with each column set to its
     default value:

          INSERT INTO TBL_NAME () VALUES();

     In strict mode, an error occurs if any column doesn't have a
     default value. Otherwise, MySQL uses the implicit default value
     for any column that does not have an explicitly defined default.

   * You can specify an expression EXPR to provide a column value. This
     might involve type conversion if the type of the expression does
     not match the type of the column, and conversion of a given value
     can result in different inserted values depending on the data
     type. For example, inserting the string `'1999.0e-2'' into an
     *Note `INT': numeric-types, *Note `FLOAT': numeric-types,
     `DECIMAL(10,6)', or *Note `YEAR': year. column results in the
     values `1999', `19.9921', `19.992100', and `1999' being inserted,
     respectively. The reason the value stored in the *Note `INT':
     numeric-types. and *Note `YEAR': year. columns is `1999' is that
     the string-to-integer conversion looks only at as much of the
     initial part of the string as may be considered a valid integer or
     year. For the floating-point and fixed-point columns, the
     string-to-floating-point conversion considers the entire string a
     valid floating-point value.

     An expression EXPR can refer to any column that was set earlier in
     a value list. For example, you can do this because the value for
     `col2' refers to `col1', which has previously been assigned:

          INSERT INTO TBL_NAME (col1,col2) VALUES(15,col1*2);

     But the following is not legal, because the value for `col1'
     refers to `col2', which is assigned after `col1':

          INSERT INTO TBL_NAME (col1,col2) VALUES(col2*2,15);

     One exception involves columns that contain `AUTO_INCREMENT'
     values. Because the `AUTO_INCREMENT' value is generated after
     other value assignments, any reference to an `AUTO_INCREMENT'
     column in the assignment returns a `0'.

*Note `INSERT': insert. statements that use `VALUES' syntax can insert
multiple rows. To do this, include multiple lists of column values,
each enclosed within parentheses and separated by commas. Example:

     INSERT INTO TBL_NAME (a,b,c) VALUES(1,2,3),(4,5,6),(7,8,9);

The values list for each row must be enclosed within parentheses.  The
following statement is illegal because the number of values in the list
does not match the number of column names:

     INSERT INTO TBL_NAME (a,b,c) VALUES(1,2,3,4,5,6,7,8,9);

`VALUE' is a synonym for `VALUES' in this context. Neither implies
anything about the number of values lists, and either may be used
whether there is a single values list or multiple lists.

The affected-rows value for an *Note `INSERT': insert. can be obtained
using the `ROW_COUNT()' function (see *Note information-functions::),
or the *Note `mysql_affected_rows()': mysql-affected-rows. C API
function (see *Note mysql-affected-rows::).

If you use an *Note `INSERT ... VALUES': insert. statement with
multiple value lists or *Note `INSERT ... SELECT': insert-select, the
statement returns an information string in this format:

     Records: 100 Duplicates: 0 Warnings: 0

`Records' indicates the number of rows processed by the statement.
(This is not necessarily the number of rows actually inserted because
`Duplicates' can be nonzero.) `Duplicates' indicates the number of rows
that could not be inserted because they would duplicate some existing
unique index value. `Warnings' indicates the number of attempts to
insert column values that were problematic in some way. Warnings can
occur under any of the following conditions:

   * Inserting `NULL' into a column that has been declared `NOT NULL'.
     For multiple-row *Note `INSERT': insert. statements or *Note
     `INSERT INTO ... SELECT': insert-select. statements, the column is
     set to the implicit default value for the column data type. This is
     `0' for numeric types, the empty string (`''') for string types,
     and the `zero' value for date and time types.  *Note `INSERT INTO
     ... SELECT': insert-select. statements are handled the same way as
     multiple-row inserts because the server does not examine the
     result set from the *Note `SELECT': select. to see whether it
     returns a single row. (For a single-row *Note `INSERT': insert, no
     warning occurs when `NULL' is inserted into a `NOT NULL' column.
     Instead, the statement fails with an error.)

   * Setting a numeric column to a value that lies outside the column's
     range. The value is clipped to the closest endpoint of the range.

   * Assigning a value such as `'10.34 a'' to a numeric column. The
     trailing nonnumeric text is stripped off and the remaining numeric
     part is inserted. If the string value has no leading numeric part,
     the column is set to `0'.

   * Inserting a string into a string column (*Note `CHAR': char, *Note
     `VARCHAR': char, *Note `TEXT': blob, or *Note `BLOB': blob.) that
     exceeds the column's maximum length. The value is truncated to the
     column's maximum length.

   * Inserting a value into a date or time column that is illegal for
     the data type. The column is set to the appropriate zero value for
     the type.

If you are using the C API, the information string can be obtained by
invoking the *Note `mysql_info()': mysql-info.  function. See *Note
mysql-info::.

If *Note `INSERT': insert. inserts a row into a table that has an
`AUTO_INCREMENT' column, you can find the value used for that column by
using the SQL `LAST_INSERT_ID()' function. From within the C API, use
the *Note `mysql_insert_id()': mysql-insert-id. function.  However, you
should note that the two functions do not always behave identically.
The behavior of *Note `INSERT': insert. statements with respect to
`AUTO_INCREMENT' columns is discussed further in *Note
information-functions::, and *Note mysql-insert-id::.

The *Note `INSERT': insert. statement supports the following modifiers:

   * If you use the `DELAYED' keyword, the server puts the row or rows
     to be inserted into a buffer, and the client issuing the *Note
     `INSERT DELAYED': insert-delayed. statement can then continue
     immediately. If the table is in use, the server holds the rows.
     When the table is free, the server begins inserting rows, checking
     periodically to see whether there are any new read requests for
     the table. If there are, the delayed row queue is suspended until
     the table becomes free again. See *Note insert-delayed::.

     `DELAYED' is ignored with *Note `INSERT ... SELECT':
     insert-select. or *Note `INSERT ... ON DUPLICATE KEY UPDATE':
     insert-on-duplicate.

     Beginning with MySQL 5.0.42, `DELAYED' is also disregarded for an
     *Note `INSERT': insert.  that uses functions accessing tables or
     triggers, or that is called from a function or a trigger.

   * If you use the `LOW_PRIORITY' keyword, execution of the *Note
     `INSERT': insert. is delayed until no other clients are reading
     from the table.  This includes other clients that began reading
     while existing clients are reading, and while the `INSERT
     LOW_PRIORITY' statement is waiting. It is possible, therefore, for
     a client that issues an `INSERT LOW_PRIORITY' statement to wait
     for a very long time (or even forever) in a read-heavy
     environment. (This is in contrast to *Note `INSERT DELAYED':
     insert-delayed, which lets the client continue at once. Note that
     `LOW_PRIORITY' should normally not be used with `MyISAM' tables
     because doing so disables concurrent inserts. See *Note
     concurrent-inserts::.

     If you specify `HIGH_PRIORITY', it overrides the effect of the
     `--low-priority-updates' option if the server was started with
     that option. It also causes concurrent inserts not to be used. See
     *Note concurrent-inserts::.

     `LOW_PRIORITY' and `HIGH_PRIORITY' affect only storage engines
     that use only table-level locking (such as `MyISAM', `MEMORY', and
     `MERGE').

   * If you use the `IGNORE' keyword, errors that occur while executing
     the *Note `INSERT': insert. statement are treated as warnings
     instead. For example, without `IGNORE', a row that duplicates an
     existing `UNIQUE' index or `PRIMARY KEY' value in the table causes
     a duplicate-key error and the statement is aborted. With `IGNORE',
     the row still is not inserted, but no error is issued. Data
     conversions that would trigger errors abort the statement if
     `IGNORE' is not specified. With `IGNORE', invalid values are
     adjusted to the closest values and inserted; warnings are produced
     but the statement does not abort. You can determine with the *Note
     `mysql_info()': mysql-info. C API function how many rows were
     actually inserted into the table.

   * If you specify `ON DUPLICATE KEY UPDATE', and a row is inserted
     that would cause a duplicate value in a `UNIQUE' index or `PRIMARY
     KEY', an *Note `UPDATE': update. of the old row is performed. The
     affected-rows value per row is 1 if the row is inserted as a new
     row and 2 if an existing row is updated. See *Note
     insert-on-duplicate::.

Inserting into a table requires the `INSERT' privilege for the table. If
the `ON DUPLICATE KEY UPDATE' clause is used and a duplicate key causes
an *Note `UPDATE': update. to be performed instead, the statement
requires the `UPDATE' privilege for the columns to be updated. For
columns that are read but not modified you need only the `SELECT'
privilege (such as for a column referenced only on the right hand side
of an COL_NAME=EXPR assignment in an `ON DUPLICATE KEY UPDATE' clause).


File: manual.info,  Node: insert-select,  Next: insert-delayed,  Prev: insert,  Up: insert

13.2.5.1 `INSERT ... SELECT' Syntax
...................................

     INSERT [LOW_PRIORITY | HIGH_PRIORITY] [IGNORE]
         [INTO] TBL_NAME [(COL_NAME,...)]
         SELECT ...
         [ ON DUPLICATE KEY UPDATE COL_NAME=EXPR, ... ]

With *Note `INSERT ... SELECT': insert-select, you can quickly insert
many rows into a table from one or many tables. For example:

     INSERT INTO tbl_temp2 (fld_id)
       SELECT tbl_temp1.fld_order_id
       FROM tbl_temp1 WHERE tbl_temp1.fld_order_id > 100;

The following conditions hold for a *Note `INSERT ... SELECT':
insert-select. statements:

   * Specify `IGNORE' to ignore rows that would cause duplicate-key
     violations.

   * `DELAYED' is ignored with *Note `INSERT ... SELECT': insert-select.

   * The target table of the *Note `INSERT': insert. statement may
     appear in the `FROM' clause of the *Note `SELECT': select. part of
     the query.  (This was not possible in some older versions of
     MySQL.)  However, you cannot insert into a table and select from
     the same table in a subquery.

     When selecting from and inserting into a table at the same time,
     MySQL creates a temporary table to hold the rows from the *Note
     `SELECT': select. and then inserts those rows into the target
     table. However, it remains true that you cannot use `INSERT INTO t
     ... SELECT ...  FROM t' when `t' is a `TEMPORARY' table, because
     `TEMPORARY' tables cannot be referred to twice in the same
     statement (see *Note temporary-table-problems::).

   * `AUTO_INCREMENT' columns work as usual.

   * To ensure that the binary log can be used to re-create the
     original tables, MySQL does not permit concurrent inserts for
     *Note `INSERT ... SELECT': insert-select. statements.

   * To avoid ambiguous column reference problems when the *Note
     `SELECT': select. and the *Note `INSERT': insert. refer to the same
     table, provide a unique alias for each table used in the *Note
     `SELECT': select. part, and qualify column names in that part with
     the appropriate alias.

In the values part of `ON DUPLICATE KEY UPDATE', you can refer to
columns in other tables, as long as you do not use `GROUP BY' in the
*Note `SELECT': select. part. One side effect is that you must qualify
nonunique column names in the values part.

The order in which rows are returned by a *Note `SELECT': select.
statement with no `ORDER BY' clause is not determined. This means that,
when using replication, there is no guarantee that such a `SELECT'
returns rows in the same order on the master and the slave; this can
lead to inconsistencies between them. To prevent this from occurring,
you should always write `INSERT ... SELECT' statements that are to be
replicated as `INSERT ... SELECT ... ORDER BY COLUMN'. The choice of
COLUMN does not matter as long as the same order for returning the rows
is enforced on both the master and the slave. See also *Note
replication-features-limit::.


File: manual.info,  Node: insert-delayed,  Next: insert-on-duplicate,  Prev: insert-select,  Up: insert

13.2.5.2 `INSERT DELAYED' Syntax
................................

     INSERT DELAYED ...

The `DELAYED' option for the *Note `INSERT': insert. statement is a
MySQL extension to standard SQL that is very useful if you have clients
that cannot or need not wait for the *Note `INSERT': insert. to
complete. This is a common situation when you use MySQL for logging and
you also periodically run *Note `SELECT': select. and *Note `UPDATE':
update. statements that take a long time to complete.

When a client uses *Note `INSERT DELAYED': insert-delayed, it gets an
okay from the server at once, and the row is queued to be inserted when
the table is not in use by any other thread.

Another major benefit of using *Note `INSERT DELAYED': insert-delayed.
is that inserts from many clients are bundled together and written in
one block. This is much faster than performing many separate inserts.

Note that *Note `INSERT DELAYED': insert-delayed. is slower than a
normal *Note `INSERT': insert. if the table is not otherwise in use.
There is also the additional overhead for the server to handle a
separate thread for each table for which there are delayed rows. This
means that you should use *Note `INSERT DELAYED': insert-delayed. only
when you are really sure that you need it.

The queued rows are held only in memory until they are inserted into
the table. This means that if you terminate *Note `mysqld': mysqld.
forcibly (for example, with `kill -9') or if *Note `mysqld': mysqld.
dies unexpectedly, _any queued rows that have not been written to disk
are lost_.

There are some constraints on the use of `DELAYED':

   * *Note `INSERT DELAYED': insert-delayed. works only with `MyISAM',
     `MEMORY', and `ARCHIVE' tables. For engines that do not support
     `DELAYED', an error occurs.

   * An error occurs for *Note `INSERT DELAYED': insert-delayed. if
     used with a table that has been locked with `LOCK TABLES' because
     the insert must be handled by a separate thread, not by the
     session that holds the lock.

   * For `MyISAM' tables, if there are no free blocks in the middle of
     the data file, concurrent *Note `SELECT': select. and *Note
     `INSERT': insert. statements are supported. Under these
     circumstances, you very seldom need to use *Note `INSERT DELAYED':
     insert-delayed. with `MyISAM'.

   * *Note `INSERT DELAYED': insert-delayed. should be used only for
     *Note `INSERT': insert. statements that specify value lists. The
     server ignores `DELAYED' for *Note `INSERT ... SELECT':
     insert-select. or *Note `INSERT ... ON DUPLICATE KEY UPDATE':
     insert-on-duplicate. statements.

   * Because the *Note `INSERT DELAYED': insert-delayed.  statement
     returns immediately, before the rows are inserted, you cannot use
     `LAST_INSERT_ID()' to get the `AUTO_INCREMENT' value that the
     statement might generate.

   * `DELAYED' rows are not visible to *Note `SELECT': select.
     statements until they actually have been inserted.

   * *Note `INSERT DELAYED': insert-delayed. is treated as a normal
     *Note `INSERT': insert. if the statement inserts multiple rows and
     binary logging is enabled.

   * `DELAYED' is ignored on slave replication servers, so that *Note
     `INSERT DELAYED': insert-delayed. is treated as a normal *Note
     `INSERT': insert. on slaves. This is because `DELAYED' could cause
     the slave to have different data than the master.

   * Pending *Note `INSERT DELAYED': insert-delayed.  statements are
     lost if a table is write locked and *Note `ALTER TABLE':
     alter-table. is used to modify the table structure.

   * *Note `INSERT DELAYED': insert-delayed. is not supported for views.

The following describes in detail what happens when you use the
`DELAYED' option to *Note `INSERT': insert. or *Note `REPLACE':
replace. In this description, the `thread' is the thread that received
an *Note `INSERT DELAYED': insert-delayed. statement and `handler' is
the thread that handles all *Note `INSERT DELAYED': insert-delayed.
statements for a particular table.

   * When a thread executes a `DELAYED' statement for a table, a
     handler thread is created to process all `DELAYED' statements for
     the table, if no such handler already exists.

   * The thread checks whether the handler has previously acquired a
     `DELAYED' lock; if not, it tells the handler thread to do so. The
     `DELAYED' lock can be obtained even if other threads have a `READ'
     or `WRITE' lock on the table. However, the handler waits for all
     *Note `ALTER TABLE': alter-table. locks or *Note `FLUSH TABLES':
     flush. statements to finish, to ensure that the table structure is
     up to date.

   * The thread executes the *Note `INSERT': insert. statement, but
     instead of writing the row to the table, it puts a copy of the
     final row into a queue that is managed by the handler thread. Any
     syntax errors are noticed by the thread and reported to the client
     program.

   * The client cannot obtain from the server the number of duplicate
     rows or the `AUTO_INCREMENT' value for the resulting row, because
     the *Note `INSERT': insert. returns before the insert operation
     has been completed. (If you use the C API, the *Note
     `mysql_info()': mysql-info. function does not return anything
     meaningful, for the same reason.)

   * The binary log is updated by the handler thread when the row is
     inserted into the table. In case of multiple-row inserts, the
     binary log is updated when the first row is inserted.

   * Each time that `delayed_insert_limit' rows are written, the
     handler checks whether any *Note `SELECT': select. statements are
     still pending. If so, it permits these to execute before
     continuing.

   * When the handler has no more rows in its queue, the table is
     unlocked. If no new *Note `INSERT DELAYED': insert-delayed.
     statements are received within `delayed_insert_timeout' seconds,
     the handler terminates.

   * If more than `delayed_queue_size' rows are pending in a specific
     handler queue, the thread requesting *Note `INSERT DELAYED':
     insert-delayed. waits until there is room in the queue. This is
     done to ensure that *Note `mysqld': mysqld. does not use all
     memory for the delayed memory queue.

   * The handler thread shows up in the MySQL process list with
     `delayed_insert' in the `Command' column. It is killed if you
     execute a *Note `FLUSH TABLES': flush. statement or kill it with
     `KILL THREAD_ID'. However, before exiting, it first stores all
     queued rows into the table. During this time it does not accept
     any new *Note `INSERT': insert. statements from other threads. If
     you execute an *Note `INSERT DELAYED': insert-delayed. statement
     after this, a new handler thread is created.

     Note that this means that *Note `INSERT DELAYED': insert-delayed.
     statements have higher priority than normal *Note `INSERT':
     insert. statements if there is an *Note `INSERT DELAYED':
     insert-delayed.  handler running. Other update statements have to
     wait until the *Note `INSERT DELAYED': insert-delayed. queue is
     empty, someone terminates the handler thread (with `KILL
     THREAD_ID'), or someone executes a *Note `FLUSH TABLES': flush.

   * The following status variables provide information about *Note
     `INSERT DELAYED': insert-delayed. statements.

     Status Variable                Meaning
     `Delayed_insert_threads'       Number of handler threads
     `Delayed_writes'               Number of rows written with *Note
                                    `INSERT DELAYED': insert-delayed.
     `Not_flushed_delayed_rows'     Number of rows waiting to be written

     You can view these variables by issuing a *Note `SHOW STATUS':
     show-status. statement or by executing a *Note `mysqladmin
     extended-status': mysqladmin.  command.


File: manual.info,  Node: insert-on-duplicate,  Prev: insert-delayed,  Up: insert

13.2.5.3 `INSERT ... ON DUPLICATE KEY UPDATE' Syntax
....................................................

If you specify `ON DUPLICATE KEY UPDATE', and a row is inserted that
would cause a duplicate value in a `UNIQUE' index or `PRIMARY KEY', an
*Note `UPDATE': update. of the old row is performed. For example, if
column `a' is declared as `UNIQUE' and contains the value `1', the
following two statements have identical effect:

     INSERT INTO table (a,b,c) VALUES (1,2,3)
       ON DUPLICATE KEY UPDATE c=c+1;

     UPDATE table SET c=c+1 WHERE a=1;

The `ON DUPLICATE KEY UPDATE' clause can contain multiple column
assignments, separated by commas.

With `ON DUPLICATE KEY UPDATE', the affected-rows value per row is 1 if
the row is inserted as a new row and 2 if an existing row is updated.

If column `b' is also unique, the *Note `INSERT': insert. is equivalent
to this *Note `UPDATE': update. statement instead:

     UPDATE table SET c=c+1 WHERE a=1 OR b=2 LIMIT 1;

If `a=1 OR b=2' matches several rows, only _one_ row is updated. In
general, you should try to avoid using an `ON DUPLICATE KEY' clause on
tables with multiple unique indexes.

You can use the `VALUES(COL_NAME)' function in the *Note `UPDATE':
update. clause to refer to column values from the *Note `INSERT':
insert. portion of the `INSERT ... UPDATE' statement. In other words,
`VALUES(COL_NAME)' in the *Note `UPDATE': update. clause refers to the
value of COL_NAME that would be inserted, had no duplicate-key conflict
occurred. This function is especially useful in multiple-row inserts.
The `VALUES()' function is meaningful only in `INSERT ... UPDATE'
statements and returns `NULL' otherwise. Example:

     INSERT INTO table (a,b,c) VALUES (1,2,3),(4,5,6)
       ON DUPLICATE KEY UPDATE c=VALUES(a)+VALUES(b);

That statement is identical to the following two statements:

     INSERT INTO table (a,b,c) VALUES (1,2,3)
       ON DUPLICATE KEY UPDATE c=3;
     INSERT INTO table (a,b,c) VALUES (4,5,6)
       ON DUPLICATE KEY UPDATE c=9;

If a table contains an `AUTO_INCREMENT' column and `INSERT ... UPDATE'
inserts a row, the `LAST_INSERT_ID()' function returns the
`AUTO_INCREMENT' value. If the statement updates a row instead,
`LAST_INSERT_ID()' is not meaningful. However, you can work around this
by using `LAST_INSERT_ID(EXPR)'.  Suppose that `id' is the
`AUTO_INCREMENT' column. To make `LAST_INSERT_ID()' meaningful for
updates, insert rows as follows:

     INSERT INTO table (a,b,c) VALUES (1,2,3)
       ON DUPLICATE KEY UPDATE id=LAST_INSERT_ID(id), c=3;

The `DELAYED' option is ignored when you use `ON DUPLICATE KEY UPDATE'.


File: manual.info,  Node: load-data,  Next: replace,  Prev: insert,  Up: sql-syntax-data-manipulation

13.2.6 `LOAD DATA INFILE' Syntax
--------------------------------

     LOAD DATA [LOW_PRIORITY | CONCURRENT] [LOCAL] INFILE 'FILE_NAME'
         [REPLACE | IGNORE]
         INTO TABLE TBL_NAME
         [CHARACTER SET CHARSET_NAME]
         [{FIELDS | COLUMNS}
             [TERMINATED BY 'STRING']
             [[OPTIONALLY] ENCLOSED BY 'CHAR']
             [ESCAPED BY 'CHAR']
         ]
         [LINES
             [STARTING BY 'STRING']
             [TERMINATED BY 'STRING']
         ]
         [IGNORE NUMBER LINES]
         [(COL_NAME_OR_USER_VAR,...)]
         [SET COL_NAME = EXPR,...]

The *Note `LOAD DATA INFILE': load-data. statement reads rows from a
text file into a table at a very high speed. The file name must be
given as a literal string.

*Note `LOAD DATA INFILE': load-data. is the complement of *Note `SELECT
... INTO OUTFILE': select-into. (See *Note select-into::.) To write
data from a table to a file, use *Note `SELECT ... INTO OUTFILE':
select-into. To read the file back into a table, use *Note `LOAD DATA
INFILE': load-data. The syntax of the `FIELDS' and `LINES' clauses is
the same for both statements.  Both clauses are optional, but `FIELDS'
must precede `LINES' if both are specified.

For more information about the efficiency of *Note `INSERT': insert.
versus *Note `LOAD DATA INFILE': load-data. and speeding up *Note `LOAD
DATA INFILE': load-data, see *Note insert-speed::.

The character set indicated by the `character_set_database' system
variable is used to interpret the information in the file.  `SET NAMES'
and the setting of `character_set_client' do not affect interpretation
of input. If the contents of the input file use a character set that
differs from the default, it is usually preferable to specify the
character set of the file by using the `CHARACTER SET' clause, which is
available as of MySQL 5.0.38. A character set of `binary' specifies `no
conversion.'

*Note `LOAD DATA INFILE': load-data. interprets all fields in the file
as having the same character set, regardless of the data types of the
columns into which field values are loaded. For proper interpretation of
file contents, you must ensure that it was written with the correct
character set. For example, if you write a data file with *Note
`mysqldump -T': mysqldump. or by issuing a *Note `SELECT ... INTO
OUTFILE': select-into. statement in *Note `mysql': mysql, be sure to
use a `--default-character-set' option with *Note `mysqldump':
mysqldump. or *Note `mysql': mysql. so that output is written in the
character set to be used when the file is loaded with *Note `LOAD DATA
INFILE': load-data.

Note that it is currently not possible to load data files that use the
`ucs2' character set.

As of MySQL 5.0.19, the `character_set_filesystem' system variable
controls the interpretation of the file name.

You can also load data files by using the *Note `mysqlimport':
mysqlimport. utility; it operates by sending a *Note `LOAD DATA
INFILE': load-data. statement to the server. The `--local' option causes
*Note `mysqlimport': mysqlimport. to read data files from the client
host. You can specify the `--compress' option to get better performance
over slow networks if the client and server support the compressed
protocol. See *Note mysqlimport::.

If you use `LOW_PRIORITY', execution of the *Note `LOAD DATA':
load-data. statement is delayed until no other clients are reading from
the table. This affects only storage engines that use only table-level
locking (such as `MyISAM', `MEMORY', and `MERGE').

If you specify `CONCURRENT' with a `MyISAM' table that satisfies the
condition for concurrent inserts (that is, it contains no free blocks
in the middle), other threads can retrieve data from the table while
*Note `LOAD DATA': load-data. is executing. Using this option affects
the performance of *Note `LOAD DATA': load-data. a bit, even if no
other thread is using the table at the same time.

`CONCURRENT' is not replicated. See *Note replication-features-load::,
for more information.

The `LOCAL' keyword, if specified, is interpreted with respect to the
client end of the connection:

   * If `LOCAL' is specified, the file is read by the client program on
     the client host and sent to the server.  The file can be given as
     a full path name to specify its exact location. If given as a
     relative path name, the name is interpreted relative to the
     directory in which the client program was started.

     When using `LOCAL' with *Note `LOAD DATA': load-data, a copy of
     the file is created in the server's temporary directory. This is
     _not_ the directory determined by the value of `tmpdir' or
     `slave_load_tmpdir', but rather the operating system's temporary
     directory, and is not configurable in the MySQL Server. (Typically
     the system temporary directory is `/tmp' on Linux systems and
     `C:\WINDOWS\TEMP' on Windows.)  Lack of sufficient space for the
     copy in this directory can cause the *Note `LOAD DATA LOCAL':
     load-data. statement to fail.

   * If `LOCAL' is not specified, the file must be located on the
     server host and is read directly by the server.  The server uses
     the following rules to locate the file:

        * If the file name is an absolute path name, the server uses it
          as given.

        * If the file name is a relative path name with one or more
          leading components, the server searches for the file relative
          to the server's data directory.

        * If a file name with no leading components is given, the
          server looks for the file in the database directory of the
          default database.

Note that, in the non-`LOCAL' case, these rules mean that a file named
as `./myfile.txt' is read from the server's data directory, whereas the
file named as `myfile.txt' is read from the database directory of the
default database. For example, if `db1' is the default database, the
following *Note `LOAD DATA': load-data. statement reads the file
`data.txt' from the database directory for `db1', even though the
statement explicitly loads the file into a table in the `db2' database:

     LOAD DATA INFILE 'data.txt' INTO TABLE db2.my_table;

Windows path names are specified using forward slashes rather than
backslashes. If you do use backslashes, you must double them.

For security reasons, when reading text files located on the server,
the files must either reside in the database directory or be readable
by all. Also, to use *Note `LOAD DATA INFILE': load-data. on server
files, you must have the `FILE' privilege. See *Note
privileges-provided::. For non-`LOCAL' load operations, if the
`secure_file_priv' system variable is set to a nonempty directory name,
the file to be loaded must be located in that directory.

Using `LOCAL' is a bit slower than letting the server access the files
directly, because the contents of the file must be sent over the
connection by the client to the server. On the other hand, you do not
need the `FILE' privilege to load local files.

With `LOCAL', the default duplicate-key handling behavior is the same
as if `IGNORE' is specified; this is because the server has no way to
stop transmission of the file in the middle of the operation. `IGNORE'
is explained further later in this section.

`LOCAL' works only if your server and your client both have been
configured to permit it. For example, if *Note `mysqld': mysqld. was
started with `--local-infile=0', `LOCAL' does not work. See *Note
load-data-local::.

On Unix, if you need *Note `LOAD DATA': load-data. to read from a pipe,
you can use the following technique (the example loads a listing of the
`/' directory into the table `db1.t1'):

     mkfifo /mysql/data/db1/ls.dat
     chmod 666 /mysql/data/db1/ls.dat
     find / -ls > /mysql/data/db1/ls.dat &
     mysql -e "LOAD DATA INFILE 'ls.dat' INTO TABLE t1" db1

Note that you must run the command that generates the data to be loaded
and the *Note `mysql': mysql. commands either on separate terminals, or
run the data generation process in the background (as shown in the
preceding example). If you do not do this, the pipe will block until
data is read by the *Note `mysql': mysql. process.

The *Note `REPLACE': replace. and `IGNORE' keywords control handling of
input rows that duplicate existing rows on unique key values:

   * If you specify *Note `REPLACE': replace, input rows replace
     existing rows. In other words, rows that have the same value for a
     primary key or unique index as an existing row. See *Note
     replace::.

   * If you specify `IGNORE', input rows that duplicate an existing row
     on a unique key value are skipped.  If you do not specify either
     option, the behavior depends on whether the `LOCAL' keyword is
     specified.  Without `LOCAL', an error occurs when a duplicate key
     value is found, and the rest of the text file is ignored. With
     `LOCAL', the default behavior is the same as if `IGNORE' is
     specified; this is because the server has no way to stop
     transmission of the file in the middle of the operation.

If you want to ignore foreign key constraints during the load
operation, you can issue a `SET foreign_key_checks = 0' statement
before executing *Note `LOAD DATA': load-data.

If you use *Note `LOAD DATA INFILE': load-data. on an empty `MyISAM'
table, all nonunique indexes are created in a separate batch (as for
*Note `REPAIR TABLE': repair-table.). Normally, this makes *Note `LOAD
DATA INFILE': load-data. much faster when you have many indexes. In some
extreme cases, you can create the indexes even faster by turning them
off with `ALTER TABLE ... DISABLE KEYS' before loading the file into
the table and using `ALTER TABLE ... ENABLE KEYS' to re-create the
indexes after loading the file. See *Note insert-speed::.

For both the *Note `LOAD DATA INFILE': load-data. and *Note `SELECT ...
INTO OUTFILE': select-into. statements, the syntax of the `FIELDS' and
`LINES' clauses is the same. Both clauses are optional, but `FIELDS'
must precede `LINES' if both are specified.

If you specify a `FIELDS' clause, each of its subclauses (`TERMINATED
BY', `[OPTIONALLY] ENCLOSED BY', and `ESCAPED BY') is also optional,
except that you must specify at least one of them.

If you specify no `FIELDS' or `LINES' clause, the defaults are the same
as if you had written this:

     FIELDS TERMINATED BY '\t' ENCLOSED BY '' ESCAPED BY '\\'
     LINES TERMINATED BY '\n' STARTING BY ''

(Backslash is the MySQL escape character within strings in SQL
statements, so to specify a literal backslash, you must specify two
backslashes for the value to be interpreted as a single backslash. The
escape sequences `'\t'' and `'\n'' specify tab and newline characters,
respectively.)

In other words, the defaults cause *Note `LOAD DATA INFILE': load-data.
to act as follows when reading input:

   * Look for line boundaries at newlines.

   * Do not skip over any line prefix.

   * Break lines into fields at tabs.

   * Do not expect fields to be enclosed within any quoting characters.

   * Interpret characters preceded by the escape character ``\'' as
     escape sequences. For example, ``\t'', ``\n'', and ``\\'' signify
     tab, newline, and backslash, respectively. See the discussion of
     `FIELDS ESCAPED BY' later for the full list of escape sequences.

Conversely, the defaults cause *Note `SELECT ... INTO OUTFILE':
select-into. to act as follows when writing output:

   * Write tabs between fields.

   * Do not enclose fields within any quoting characters.

   * Use ``\'' to escape instances of tab, newline, or ``\'' that occur
     within field values.

   * Write newlines at the ends of lines.

*Note*:

If you have generated the text file on a Windows system, you might have
to use `LINES TERMINATED BY '\r\n'' to read the file properly, because
Windows programs typically use two characters as a line terminator.
Some programs, such as `WordPad', might use `\r' as a line terminator
when writing files. To read such files, use `LINES TERMINATED BY '\r''.

If all the lines you want to read in have a common prefix that you want
to ignore, you can use `LINES STARTING BY 'PREFIX_STRING'' to skip over
the prefix, _and anything before it_. If a line does not include the
prefix, the entire line is skipped. Suppose that you issue the
following statement:

     LOAD DATA INFILE '/tmp/test.txt' INTO TABLE test
       FIELDS TERMINATED BY ','  LINES STARTING BY 'xxx';

If the data file looks like this:

     xxx"abc",1
     something xxx"def",2
     "ghi",3

The resulting rows will be `("abc",1)' and `("def",2)'. The third row
in the file is skipped because it does not contain the prefix.

The `IGNORE NUMBER LINES' option can be used to ignore lines at the
start of the file. For example, you can use `IGNORE 1 LINES' to skip
over an initial header line containing column names:

     LOAD DATA INFILE '/tmp/test.txt' INTO TABLE test IGNORE 1 LINES;

When you use *Note `SELECT ... INTO OUTFILE': select-into. in tandem
with *Note `LOAD DATA INFILE': load-data. to write data from a database
into a file and then read the file back into the database later, the
field- and line-handling options for both statements must match.
Otherwise, *Note `LOAD DATA INFILE': load-data. will not interpret the
contents of the file properly. Suppose that you use *Note `SELECT ...
INTO OUTFILE': select-into. to write a file with fields delimited by
commas:

     SELECT * INTO OUTFILE 'data.txt'
       FIELDS TERMINATED BY ','
       FROM table2;

To read the comma-delimited file back in, the correct statement would
be:

     LOAD DATA INFILE 'data.txt' INTO TABLE table2
       FIELDS TERMINATED BY ',';

If instead you tried to read in the file with the statement shown
following, it wouldn't work because it instructs *Note `LOAD DATA
INFILE': load-data. to look for tabs between fields:

     LOAD DATA INFILE 'data.txt' INTO TABLE table2
       FIELDS TERMINATED BY '\t';

The likely result is that each input line would be interpreted as a
single field.

*Note `LOAD DATA INFILE': load-data. can be used to read files obtained
from external sources. For example, many programs can export data in
comma-separated values (CSV) format, such that lines have fields
separated by commas and enclosed within double quotation marks, with an
initial line of column names. If the lines in such a file are
terminated by carriage return/newline pairs, the statement shown here
illustrates the field- and line-handling options you would use to load
the file:

     LOAD DATA INFILE 'data.txt' INTO TABLE TBL_NAME
       FIELDS TERMINATED BY ',' ENCLOSED BY '"'
       LINES TERMINATED BY '\r\n'
       IGNORE 1 LINES;

If the input values are not necessarily enclosed within quotation
marks, use `OPTIONALLY' before the `ENCLOSED BY' keywords.

Any of the field- or line-handling options can specify an empty string
(`'''). If not empty, the `FIELDS [OPTIONALLY] ENCLOSED BY' and `FIELDS
ESCAPED BY' values must be a single character. The `FIELDS TERMINATED
BY', `LINES STARTING BY', and `LINES TERMINATED BY' values can be more
than one character. For example, to write lines that are terminated by
carriage return/linefeed pairs, or to read a file containing such
lines, specify a `LINES TERMINATED BY '\r\n'' clause.

To read a file containing jokes that are separated by lines consisting
of `%%', you can do this

     CREATE TABLE jokes
       (a INT NOT NULL AUTO_INCREMENT PRIMARY KEY,
       joke TEXT NOT NULL);
     LOAD DATA INFILE '/tmp/jokes.txt' INTO TABLE jokes
       FIELDS TERMINATED BY ''
       LINES TERMINATED BY '\n%%\n' (joke);

`FIELDS [OPTIONALLY] ENCLOSED BY' controls quoting of fields. For output
(*Note `SELECT ... INTO OUTFILE': select-into.), if you omit the word
`OPTIONALLY', all fields are enclosed by the `ENCLOSED BY' character.
An example of such output (using a comma as the field delimiter) is
shown here:

     "1","a string","100.20"
     "2","a string containing a , comma","102.20"
     "3","a string containing a \" quote","102.20"
     "4","a string containing a \", quote and comma","102.20"

If you specify `OPTIONALLY', the `ENCLOSED BY' character is used only
to enclose values from columns that have a string data type (such as
*Note `CHAR': char, *Note `BINARY': binary-varbinary, *Note `TEXT':
blob, or *Note `ENUM': enum.):

     1,"a string",100.20
     2,"a string containing a , comma",102.20
     3,"a string containing a \" quote",102.20
     4,"a string containing a \", quote and comma",102.20

Note that occurrences of the `ENCLOSED BY' character within a field
value are escaped by prefixing them with the `ESCAPED BY' character.
Also note that if you specify an empty `ESCAPED BY' value, it is
possible to inadvertently generate output that cannot be read properly
by *Note `LOAD DATA INFILE': load-data. For example, the preceding
output just shown would appear as follows if the escape character is
empty. Observe that the second field in the fourth line contains a comma
following the quote, which (erroneously) appears to terminate the field:

     1,"a string",100.20
     2,"a string containing a , comma",102.20
     3,"a string containing a " quote",102.20
     4,"a string containing a ", quote and comma",102.20

For input, the `ENCLOSED BY' character, if present, is stripped from
the ends of field values. (This is true regardless of whether
`OPTIONALLY' is specified; `OPTIONALLY' has no effect on input
interpretation.) Occurrences of the `ENCLOSED BY' character preceded by
the `ESCAPED BY' character are interpreted as part of the current field
value.

If the field begins with the `ENCLOSED BY' character, instances of that
character are recognized as terminating a field value only if followed
by the field or line `TERMINATED BY' sequence. To avoid ambiguity,
occurrences of the `ENCLOSED BY' character within a field value can be
doubled and are interpreted as a single instance of the character. For
example, if `ENCLOSED BY '"'' is specified, quotation marks are handled
as shown here:

     "The ""BIG"" boss"  -> The "BIG" boss
     The "BIG" boss      -> The "BIG" boss
     The ""BIG"" boss    -> The ""BIG"" boss

`FIELDS ESCAPED BY' controls how to read or write special characters:

   * For input, if the `FIELDS ESCAPED BY' character is not empty,
     occurrences of that character are stripped and the following
     character is taken literally as part of a field value. Some
     two-character sequences that are exceptions, where the first
     character is the escape character.  These sequences are shown in
     the following table (using ``\'' for the escape character).  The
     rules for `NULL' handling are described later in this section.

     Character  Escape Sequence
     `\0'       An ASCII NUL (`0x00') character
     `\b'       A backspace character
     `\n'       A newline (linefeed) character
     `\r'       A carriage return character
     `\t'       A tab character.
     `\Z'       ASCII 26 (Control+Z)
     `\N'       NULL

     For more information about ``\''-escape syntax, see *Note
     string-literals::.

     If the `FIELDS ESCAPED BY' character is empty, escape-sequence
     interpretation does not occur.

   * For output, if the `FIELDS ESCAPED BY' character is not empty, it
     is used to prefix the following characters on output:

        * The `FIELDS ESCAPED BY' character

        * The `FIELDS [OPTIONALLY] ENCLOSED BY' character

        * The first character of the `FIELDS TERMINATED BY' and `LINES
          TERMINATED BY' values

        * ASCII `0' (what is actually written following the escape
          character is ASCII ``0'', not a zero-valued byte)

     If the `FIELDS ESCAPED BY' character is empty, no characters are
     escaped and `NULL' is output as `NULL', not `\N'. It is probably
     not a good idea to specify an empty escape character, particularly
     if field values in your data contain any of the characters in the
     list just given.

In certain cases, field- and line-handling options interact:

   * If `LINES TERMINATED BY' is an empty string and `FIELDS TERMINATED
     BY' is nonempty, lines are also terminated with `FIELDS TERMINATED
     BY'.

   * If the `FIELDS TERMINATED BY' and `FIELDS ENCLOSED BY' values are
     both empty (`'''), a fixed-row (nondelimited) format is used. With
     fixed-row format, no delimiters are used between fields (but you
     can still have a line terminator). Instead, column values are read
     and written using a field width wide enough to hold all values in
     the field. For *Note `TINYINT': numeric-types, *Note `SMALLINT':
     numeric-types, *Note `MEDIUMINT': numeric-types, *Note `INT':
     numeric-types, and *Note `BIGINT': numeric-types, the field widths
     are 4, 6, 8, 11, and 20, respectively, no matter what the declared
     display width is.

     `LINES TERMINATED BY' is still used to separate lines. If a line
     does not contain all fields, the rest of the columns are set to
     their default values. If you do not have a line terminator, you
     should set this to `'''. In this case, the text file must contain
     all fields for each row.

     Fixed-row format also affects handling of `NULL' values, as
     described later. Note that fixed-size format does not work if you
     are using a multi-byte character set.

     *Note*:

     Before MySQL 5.0.6, fixed-row format used the display width of the
     column. For example, `INT(4)' was read or written using a field
     with a width of 4. However, if the column contained wider values,
     they were dumped to their full width, leading to the possibility
     of a `ragged' field holding values of different widths. Using a
     field wide enough to hold all values in the field prevents this
     problem. However, data files written before this change was made
     might not be reloaded correctly with *Note `LOAD DATA INFILE':
     load-data. for MySQL 5.0.6 and up. This change also affects data
     files read by *Note `mysqlimport': mysqlimport.  and written by
     *Note `mysqldump --tab': mysqldump, which use *Note `LOAD DATA
     INFILE': load-data. and *Note `SELECT ... INTO OUTFILE':
     select-into.

Handling of `NULL' values varies according to the `FIELDS' and `LINES'
options in use:

   * For the default `FIELDS' and `LINES' values, `NULL' is written as
     a field value of `\N' for output, and a field value of `\N' is
     read as `NULL' for input (assuming that the `ESCAPED BY' character
     is ``\'').

   * If `FIELDS ENCLOSED BY' is not empty, a field containing the
     literal word `NULL' as its value is read as a `NULL' value. This
     differs from the word `NULL' enclosed within `FIELDS ENCLOSED BY'
     characters, which is read as the string `'NULL''.

   * If `FIELDS ESCAPED BY' is empty, `NULL' is written as the word
     `NULL'.

   * With fixed-row format (which is used when `FIELDS TERMINATED BY'
     and `FIELDS ENCLOSED BY' are both empty), `NULL' is written as an
     empty string. Note that this causes both `NULL' values and empty
     strings in the table to be indistinguishable when written to the
     file because both are written as empty strings. If you need to be
     able to tell the two apart when reading the file back in, you
     should not use fixed-row format.

An attempt to load `NULL' into a `NOT NULL' column causes assignment of
the implicit default value for the column's data type and a warning, or
an error in strict SQL mode. Implicit default values are discussed in
*Note data-type-defaults::.

Some cases are not supported by *Note `LOAD DATA INFILE': load-data.:

   * Fixed-size rows (`FIELDS TERMINATED BY' and `FIELDS ENCLOSED BY'
     both empty) and *Note `BLOB': blob. or *Note `TEXT': blob. columns.

   * If you specify one separator that is the same as or a prefix of
     another, *Note `LOAD DATA INFILE': load-data. cannot interpret the
     input properly. For example, the following `FIELDS' clause would
     cause problems:

          FIELDS TERMINATED BY '"' ENCLOSED BY '"'

   * If `FIELDS ESCAPED BY' is empty, a field value that contains an
     occurrence of `FIELDS ENCLOSED BY' or `LINES TERMINATED BY'
     followed by the `FIELDS TERMINATED BY' value causes *Note `LOAD
     DATA INFILE': load-data. to stop reading a field or line too early.
     This happens because *Note `LOAD DATA INFILE': load-data. cannot
     properly determine where the field or line value ends.

The following example loads all columns of the `persondata' table:

     LOAD DATA INFILE 'persondata.txt' INTO TABLE persondata;

By default, when no column list is provided at the end of the *Note
`LOAD DATA INFILE': load-data. statement, input lines are expected to
contain a field for each table column. If you want to load only some of
a table's columns, specify a column list:

     LOAD DATA INFILE 'persondata.txt' INTO TABLE persondata (col1,col2,...);

You must also specify a column list if the order of the fields in the
input file differs from the order of the columns in the table.
Otherwise, MySQL cannot tell how to match input fields with table
columns.

Before MySQL 5.0.3, the column list must contain only names of columns
in the table being loaded, and the `SET' clause is not supported. As of
MySQL 5.0.3, the column list can contain either column names or user
variables. With user variables, the `SET' clause enables you to perform
transformations on their values before assigning the result to columns.

User variables in the `SET' clause can be used in several ways. The
following example uses the first input column directly for the value of
`t1.column1', and assigns the second input column to a user variable
that is subjected to a division operation before being used for the
value of `t1.column2':

     LOAD DATA INFILE 'file.txt'
       INTO TABLE t1
       (column1, @var1)
       SET column2 = @var1/100;

The `SET' clause can be used to supply values not derived from the
input file. The following statement sets `column3' to the current date
and time:

     LOAD DATA INFILE 'file.txt'
       INTO TABLE t1
       (column1, column2)
       SET column3 = CURRENT_TIMESTAMP;

You can also discard an input value by assigning it to a user variable
and not assigning the variable to a table column:

     LOAD DATA INFILE 'file.txt'
       INTO TABLE t1
       (column1, @dummy, column2, @dummy, column3);

Use of the column/variable list and `SET' clause is subject to the
following restrictions:

   * Assignments in the `SET' clause should have only column names on
     the left hand side of assignment operators.

   * You can use subqueries in the right hand side of `SET'
     assignments. A subquery that returns a value to be assigned to a
     column may be a scalar subquery only. Also, you cannot use a
     subquery to select from the table that is being loaded.

   * Lines ignored by an `IGNORE' clause are not processed for the
     column/variable list or `SET' clause.

   * User variables cannot be used when loading data with fixed-row
     format because user variables do not have a display width.

When processing an input line, *Note `LOAD DATA': load-data. splits it
into fields and uses the values according to the column/variable list
and the `SET' clause, if they are present. Then the resulting row is
inserted into the table. If there are `BEFORE INSERT' or `AFTER INSERT'
triggers for the table, they are activated before or after inserting
the row, respectively.

If an input line has too many fields, the extra fields are ignored and
the number of warnings is incremented.

If an input line has too few fields, the table columns for which input
fields are missing are set to their default values. Default value
assignment is described in *Note data-type-defaults::.

An empty field value is interpreted differently than if the field value
is missing:

   * For string types, the column is set to the empty string.

   * For numeric types, the column is set to `0'.

   * For date and time types, the column is set to the appropriate
     `zero' value for the type. See *Note date-and-time-types::.

These are the same values that result if you assign an empty string
explicitly to a string, numeric, or date or time type explicitly in an
*Note `INSERT': insert. or *Note `UPDATE': update. statement.

*Note `TIMESTAMP': datetime. columns are set to the current date and
time only if there is a `NULL' value for the column (that is, `\N') and
the column is not declared to permit `NULL' values, or if the *Note
`TIMESTAMP': datetime. column's default value is the current timestamp
and it is omitted from the field list when a field list is specified.

*Note `LOAD DATA INFILE': load-data. regards all input as strings, so
you cannot use numeric values for *Note `ENUM': enum. or *Note `SET':
set. columns the way you can with *Note `INSERT': insert. statements.
All *Note `ENUM': enum. and *Note `SET': set. values must be specified
as strings.

*Note `BIT': numeric-types. values cannot be loaded using binary
notation (for example, `b'011010''). To work around this, specify the
values as regular integers and use the `SET' clause to convert them so
that MySQL performs a numeric type conversion and loads them into the
*Note `BIT': numeric-types. column properly:

     shell> cat /tmp/bit_test.txt
     2
     127
     shell> mysql test
     mysql> LOAD DATA INFILE '/tmp/bit_test.txt'
         -> INTO TABLE bit_test (@var1) SET b= CAST(@var1 AS UNSIGNED);
     Query OK, 2 rows affected (0.00 sec)
     Records: 2  Deleted: 0  Skipped: 0  Warnings: 0

     mysql> SELECT BIN(b+0) FROM bit_test;
     +----------+
     | bin(b+0) |
     +----------+
     | 10       |
     | 1111111  |
     +----------+
     2 rows in set (0.00 sec)

When the *Note `LOAD DATA INFILE': load-data. statement finishes, it
returns an information string in the following format:

     Records: 1  Deleted: 0  Skipped: 0  Warnings: 0

If you are using the C API, you can get information about the statement
by calling the *Note `mysql_info()': mysql-info. function. See *Note
mysql-info::.

Warnings occur under the same circumstances as when values are inserted
using the *Note `INSERT': insert. statement (see *Note insert::),
except that *Note `LOAD DATA INFILE': load-data. also generates
warnings when there are too few or too many fields in the input row.
The warnings are not stored anywhere; the number of warnings can be
used only as an indication of whether everything went well.

You can use *Note `SHOW WARNINGS': show-warnings. to get a list of the
first `max_error_count' warnings as information about what went wrong.
See *Note show-warnings::.


File: manual.info,  Node: replace,  Next: select,  Prev: load-data,  Up: sql-syntax-data-manipulation

13.2.7 `REPLACE' Syntax
-----------------------

     REPLACE [LOW_PRIORITY | DELAYED]
         [INTO] TBL_NAME [(COL_NAME,...)]
         {VALUES | VALUE} ({EXPR | DEFAULT},...),(...),...

Or:

     REPLACE [LOW_PRIORITY | DELAYED]
         [INTO] TBL_NAME
         SET COL_NAME={EXPR | DEFAULT}, ...

Or:

     REPLACE [LOW_PRIORITY | DELAYED]
         [INTO] TBL_NAME [(COL_NAME,...)]
         SELECT ...

*Note `REPLACE': replace. works exactly like *Note `INSERT': insert,
except that if an old row in the table has the same value as a new row
for a `PRIMARY KEY' or a `UNIQUE' index, the old row is deleted before
the new row is inserted. See *Note insert::.

*Note `REPLACE': replace. is a MySQL extension to the SQL standard. It
either inserts, or _deletes_ and inserts. For another MySQL extension
to standard SQL--that either inserts or _updates_--see *Note
insert-on-duplicate::.

Note that unless the table has a `PRIMARY KEY' or `UNIQUE' index, using
a *Note `REPLACE': replace. statement makes no sense.  It becomes
equivalent to *Note `INSERT': insert, because there is no index to be
used to determine whether a new row duplicates another.

Values for all columns are taken from the values specified in the *Note
`REPLACE': replace. statement. Any missing columns are set to their
default values, just as happens for *Note `INSERT': insert. You cannot
refer to values from the current row and use them in the new row. If
you use an assignment such as `SET COL_NAME = COL_NAME + 1', the
reference to the column name on the right hand side is treated as
`DEFAULT(COL_NAME)', so the assignment is equivalent to `SET COL_NAME =
DEFAULT(COL_NAME) + 1'.

To use *Note `REPLACE': replace, you must have both the `INSERT' and
`DELETE' privileges for the table.

The *Note `REPLACE': replace. statement returns a count to indicate the
number of rows affected. This is the sum of the rows deleted and
inserted. If the count is 1 for a single-row *Note `REPLACE': replace,
a row was inserted and no rows were deleted. If the count is greater
than 1, one or more old rows were deleted before the new row was
inserted. It is possible for a single row to replace more than one old
row if the table contains multiple unique indexes and the new row
duplicates values for different old rows in different unique indexes.

The affected-rows count makes it easy to determine whether *Note
`REPLACE': replace. only added a row or whether it also replaced any
rows: Check whether the count is 1 (added) or greater (replaced).

If you are using the C API, the affected-rows count can be obtained
using the *Note `mysql_affected_rows()': mysql-affected-rows. function.

Currently, you cannot replace into a table and select from the same
table in a subquery.

MySQL uses the following algorithm for *Note `REPLACE': replace. (and
`LOAD DATA ...  REPLACE'):

  1. Try to insert the new row into the table

  2. While the insertion fails because a duplicate-key error occurs for
     a primary key or unique index:

       1. Delete from the table the conflicting row that has the
          duplicate key value

       2. Try again to insert the new row into the table

It is possible that in the case of a duplicate-key error, a storage
engine may perform the `REPLACE' as an update rather than a delete plus
insert, but the semantics are the same. There are no user-visible
effects other than a possible difference in how the storage engine
increments `Handler_XXX' status variables.


File: manual.info,  Node: select,  Next: subqueries,  Prev: replace,  Up: sql-syntax-data-manipulation

13.2.8 `SELECT' Syntax
----------------------

* Menu:

* select-into::                  `SELECT ... INTO' Syntax
* join::                         `JOIN' Syntax
* index-hints::                  Index Hint Syntax
* union::                        `UNION' Syntax

     SELECT
         [ALL | DISTINCT | DISTINCTROW ]
           [HIGH_PRIORITY]
           [STRAIGHT_JOIN]
           [SQL_SMALL_RESULT] [SQL_BIG_RESULT] [SQL_BUFFER_RESULT]
           [SQL_CACHE | SQL_NO_CACHE] [SQL_CALC_FOUND_ROWS]
         SELECT_EXPR [, SELECT_EXPR ...]
         [FROM TABLE_REFERENCES
         [WHERE WHERE_CONDITION]
         [GROUP BY {COL_NAME | EXPR | POSITION}
           [ASC | DESC], ... [WITH ROLLUP]]
         [HAVING WHERE_CONDITION]
         [ORDER BY {COL_NAME | EXPR | POSITION}
           [ASC | DESC], ...]
         [LIMIT {[OFFSET,] ROW_COUNT | ROW_COUNT OFFSET OFFSET}]
         [PROCEDURE PROCEDURE_NAME(ARGUMENT_LIST)]
         [INTO OUTFILE 'FILE_NAME' EXPORT_OPTIONS
           | INTO DUMPFILE 'FILE_NAME'
           | INTO VAR_NAME [, VAR_NAME]]
         [FOR UPDATE | LOCK IN SHARE MODE]]

*Note `SELECT': select. is used to retrieve rows selected from one or
more tables, and can include *Note `UNION': union. statements and
subqueries.  See *Note union::, and *Note subqueries::.

The most commonly used clauses of *Note `SELECT': select. statements
are these:

   * Each SELECT_EXPR indicates a column that you want to retrieve.
     There must be at least one SELECT_EXPR.

   * TABLE_REFERENCES indicates the table or tables from which to
     retrieve rows. Its syntax is described in *Note join::.

   * The `WHERE' clause, if given, indicates the condition or
     conditions that rows must satisfy to be selected.  WHERE_CONDITION
     is an expression that evaluates to true for each row to be
     selected. The statement selects all rows if there is no `WHERE'
     clause.

     In the `WHERE' expression, you can use any of the functions and
     operators that MySQL supports, except for aggregate (summary)
     functions. See *Note expressions::, and *Note functions::.

*Note `SELECT': select. can also be used to retrieve rows computed
without reference to any table.

For example:

     mysql> SELECT 1 + 1;
             -> 2

You are permitted to specify `DUAL' as a dummy table name in situations
where no tables are referenced:

     mysql> SELECT 1 + 1 FROM DUAL;
             -> 2

`DUAL' is purely for the convenience of people who require that all
*Note `SELECT': select.  statements should have `FROM' and possibly
other clauses. MySQL may ignore the clauses. MySQL does not require
`FROM DUAL' if no tables are referenced.

In general, clauses used must be given in exactly the order shown in
the syntax description. For example, a `HAVING' clause must come after
any `GROUP BY' clause and before any `ORDER BY' clause. The exception
is that the `INTO' clause can appear either as shown in the syntax
description or immediately following the SELECT_EXPR list. For more
information about `INTO', see *Note select-into::.

The list of SELECT_EXPR terms comprises the select list that indicates
which columns to retrieve. Terms specify a column or expression or can
use `*'-shorthand:

   * A select list consisting only of a single unqualified `*' can be
     used as shorthand to select all columns from all tables:

          SELECT * FROM t1 INNER JOIN t2 ...

   * `TBL_NAME.*' can be used as a qualified shorthand to select all
     columns from the named table:

          SELECT t1.*, t2.* FROM t1 INNER JOIN t2 ...

   * Use of an unqualified `*' with other items in the select list may
     produce a parse error. To avoid this problem, use a qualified
     `TBL_NAME.*' reference

          SELECT AVG(score), t1.* FROM t1 ...

The following list provides additional information about other `SELECT'
clauses:

   * A SELECT_EXPR can be given an alias using `AS ALIAS_NAME'. The
     alias is used as the expression's column name and can be used in
     `GROUP BY', `ORDER BY', or `HAVING' clauses. For example:

          SELECT CONCAT(last_name,', ',first_name) AS full_name
            FROM mytable ORDER BY full_name;

     The `AS' keyword is optional when aliasing a SELECT_EXPR with an
     identifier. The preceding example could have been written like
     this:

          SELECT CONCAT(last_name,', ',first_name) full_name
            FROM mytable ORDER BY full_name;

     However, because the `AS' is optional, a subtle problem can occur
     if you forget the comma between two SELECT_EXPR expressions: MySQL
     interprets the second as an alias name. For example, in the
     following statement, `columnb' is treated as an alias name:

          SELECT columna columnb FROM mytable;

     For this reason, it is good practice to be in the habit of using
     `AS' explicitly when specifying column aliases.

     It is not permissible to refer to a column alias in a `WHERE'
     clause, because the column value might not yet be determined when
     the `WHERE' clause is executed. See *Note problems-with-alias::.

   * The `FROM TABLE_REFERENCES' clause indicates the table or tables
     from which to retrieve rows. If you name more than one table, you
     are performing a join. For information on join syntax, see *Note
     join::. For each table specified, you can optionally specify an
     alias.

          TBL_NAME [[AS] ALIAS] [INDEX_HINT]

     The use of index hints provides the optimizer with information
     about how to choose indexes during query processing. For a
     description of the syntax for specifying these hints, see *Note
     index-hints::.

     You can use `SET max_seeks_for_key=VALUE' as an alternative way to
     force MySQL to prefer key scans instead of table scans. See *Note
     server-system-variables::.

   * You can refer to a table within the default database as TBL_NAME,
     or as DB_NAME.TBL_NAME to specify a database explicitly. You can
     refer to a column as COL_NAME, TBL_NAME.COL_NAME, or
     DB_NAME.TBL_NAME.COL_NAME.  You need not specify a TBL_NAME or
     DB_NAME.TBL_NAME prefix for a column reference unless the
     reference would be ambiguous. See *Note identifier-qualifiers::,
     for examples of ambiguity that require the more explicit column
     reference forms.

   * A table reference can be aliased using `TBL_NAME AS ALIAS_NAME' or
     TBL_NAME ALIAS_NAME:

          SELECT t1.name, t2.salary FROM employee AS t1, info AS t2
            WHERE t1.name = t2.name;

          SELECT t1.name, t2.salary FROM employee t1, info t2
            WHERE t1.name = t2.name;

   * Columns selected for output can be referred to in `ORDER BY' and
     `GROUP BY' clauses using column names, column aliases, or column
     positions. Column positions are integers and begin with 1:

          SELECT college, region, seed FROM tournament
            ORDER BY region, seed;

          SELECT college, region AS r, seed AS s FROM tournament
            ORDER BY r, s;

          SELECT college, region, seed FROM tournament
            ORDER BY 2, 3;

     To sort in reverse order, add the `DESC' (descending) keyword to
     the name of the column in the `ORDER BY' clause that you are
     sorting by.  The default is ascending order; this can be specified
     explicitly using the `ASC' keyword.

     If `ORDER BY' occurs within a subquery and also is applied in the
     outer query, the outermost `ORDER BY' takes precedence. For
     example, results for the following statement are sorted in
     descending order, not ascending order:

          (SELECT ... ORDER BY a) ORDER BY a DESC;

     Use of column positions is deprecated because the syntax has been
     removed from the SQL standard.

   * If you use `GROUP BY', output rows are sorted according to the
     `GROUP BY' columns as if you had an `ORDER BY' for the same
     columns. To avoid the overhead of sorting that `GROUP BY'
     produces, add `ORDER BY NULL':

          SELECT a, COUNT(b) FROM test_table GROUP BY a ORDER BY NULL;

   * MySQL extends the `GROUP BY' clause so that you can also specify
     `ASC' and `DESC' after columns named in the clause:

          SELECT a, COUNT(b) FROM test_table GROUP BY a DESC;

   * MySQL extends the use of `GROUP BY' to permit selecting fields
     that are not mentioned in the `GROUP BY' clause. If you are not
     getting the results that you expect from your query, please read
     the description of `GROUP BY' found in *Note
     group-by-functions-and-modifiers::.

   * `GROUP BY' permits a `WITH ROLLUP' modifier. See *Note
     group-by-modifiers::.

   * The `HAVING' clause is applied nearly last, just before items are
     sent to the client, with no optimization. (`LIMIT' is applied after
     `HAVING'.)

     A `HAVING' clause can refer to any column or alias named in a
     SELECT_EXPR in the *Note `SELECT': select. list or in outer
     subqueries, and to aggregate functions. However, the SQL standard
     requires that `HAVING' must reference only columns in the `GROUP
     BY' clause or columns used in aggregate functions. To accommodate
     both standard SQL and the MySQL-specific behavior of being able to
     refer columns in the *Note `SELECT': select. list, MySQL 5.0.2 and
     up permit `HAVING' to refer to columns in the *Note `SELECT':
     select. list, columns in the `GROUP BY' clause, columns in outer
     subqueries, and to aggregate functions.

     For example, the following statement works in MySQL 5.0.2 but
     produces an error for earlier versions:

          mysql> SELECT COUNT(*) FROM t GROUP BY col1 HAVING col1 = 2;

     If the `HAVING' clause refers to a column that is ambiguous, a
     warning occurs. In the following statement, `col2' is ambiguous
     because it is used as both an alias and a column name:

          SELECT COUNT(col1) AS col2 FROM t GROUP BY col2 HAVING col2 = 2;

     Preference is given to standard SQL behavior, so if a `HAVING'
     column name is used both in `GROUP BY' and as an aliased column in
     the output column list, preference is given to the column in the
     `GROUP BY' column.

   * Do not use `HAVING' for items that should be in the `WHERE'
     clause. For example, do not write the following:

          SELECT COL_NAME FROM TBL_NAME HAVING COL_NAME > 0;

     Write this instead:

          SELECT COL_NAME FROM TBL_NAME WHERE COL_NAME > 0;

   * The `HAVING' clause can refer to aggregate functions, which the
     `WHERE' clause cannot:

          SELECT user, MAX(salary) FROM users
            GROUP BY user HAVING MAX(salary) > 10;

     (This did not work in some older versions of MySQL.)

   * MySQL permits duplicate column names. That is, there can be more
     than one SELECT_EXPR with the same name. This is an extension to
     standard SQL. Because MySQL also permits `GROUP BY' and `HAVING'
     to refer to SELECT_EXPR values, this can result in an ambiguity:

          SELECT 12 AS a, a FROM t GROUP BY a;

     In that statement, both columns have the name `a'. To ensure that
     the correct column is used for grouping, use different names for
     each SELECT_EXPR.

   * MySQL resolves unqualified column or alias references in `ORDER
     BY' clauses by searching in the SELECT_EXPR values, then in the
     columns of the tables in the `FROM' clause.  For `GROUP BY' or
     `HAVING' clauses, it searches the `FROM' clause before searching
     in the SELECT_EXPR values. (For `GROUP BY' and `HAVING', this
     differs from the pre-MySQL 5.0 behavior that used the same rules
     as for `ORDER BY'.)

   * The `LIMIT' clause can be used to constrain the number of rows
     returned by the *Note `SELECT': select. statement.  `LIMIT' takes
     one or two numeric arguments, which must both be nonnegative
     integer constants (except when using prepared statements).

     With two arguments, the first argument specifies the offset of the
     first row to return, and the second specifies the maximum number
     of rows to return. The offset of the initial row is 0 (not 1):

          SELECT * FROM tbl LIMIT 5,10;  # Retrieve rows 6-15

     To retrieve all rows from a certain offset up to the end of the
     result set, you can use some large number for the second
     parameter. This statement retrieves all rows from the 96th row to
     the last:

          SELECT * FROM tbl LIMIT 95,18446744073709551615;

     With one argument, the value specifies the number of rows to
     return from the beginning of the result set:

          SELECT * FROM tbl LIMIT 5;     # Retrieve first 5 rows

     In other words, `LIMIT ROW_COUNT' is equivalent to `LIMIT 0,
     ROW_COUNT'.

     For prepared statements, you can use placeholders (supported as of
     MySQL version 5.0.7). The following statements will return one row
     from the `tbl' table:

          SET @a=1;
          PREPARE STMT FROM 'SELECT * FROM tbl LIMIT ?';
          EXECUTE STMT USING @a;

     The following statements will return the second to sixth row from
     the `tbl' table:

          SET @skip=1; SET @numrows=5;
          PREPARE STMT FROM 'SELECT * FROM tbl LIMIT ?, ?';
          EXECUTE STMT USING @skip, @numrows;

     For compatibility with PostgreSQL, MySQL also supports the `LIMIT
     ROW_COUNT OFFSET OFFSET' syntax.

     If `LIMIT' occurs within a subquery and also is applied in the
     outer query, the outermost `LIMIT' takes precedence. For example,
     the following statement produces two rows, not one:

          (SELECT ... LIMIT 1) LIMIT 2;

   * A `PROCEDURE' clause names a procedure that should process the
     data in the result set. For an example, see *Note
     procedure-analyse::, which describes `ANALYSE', a procedure that
     can be used to obtain suggestions for optimal column data types
     that may help reduce table sizes.

   * The *Note `SELECT ... INTO': select-into. form of *Note `SELECT':
     select.  enables the query result to be written to a file or
     stored in variables. For more information, see *Note select-into::.

   * If you use `FOR UPDATE' with a storage engine that uses page or
     row locks, rows examined by the query are write-locked until the
     end of the current transaction. Using `LOCK IN SHARE MODE' sets a
     shared lock that permits other transactions to read the examined
     rows but not to update or delete them. See *Note
     innodb-locking-reads::.

Following the *Note `SELECT': select. keyword, you can use a number of
options that affect the operation of the statement. `HIGH_PRIORITY',
`STRAIGHT_JOIN', and options beginning with `SQL_' are MySQL extensions
to standard SQL.

   * The `ALL' and `DISTINCT' options specify whether duplicate rows
     should be returned.  `ALL' (the default) specifies that all
     matching rows should be returned, including duplicates.
     `DISTINCT' specifies removal of duplicate rows from the result
     set. It is an error to specify both options. `DISTINCTROW' is a
     synonym for `DISTINCT'.

   * `HIGH_PRIORITY' gives the *Note `SELECT': select. higher priority
     than a statement that updates a table. You should use this only for
     queries that are very fast and must be done at once. A `SELECT
     HIGH_PRIORITY' query that is issued while the table is locked for
     reading runs even if there is an update statement waiting for the
     table to be free. This affects only storage engines that use only
     table-level locking (such as `MyISAM', `MEMORY', and `MERGE').

     `HIGH_PRIORITY' cannot be used with *Note `SELECT': select.
     statements that are part of a *Note `UNION': union.

   * `STRAIGHT_JOIN' forces the optimizer to join the tables in the
     order in which they are listed in the `FROM' clause. You can use
     this to speed up a query if the optimizer joins the tables in
     nonoptimal order.  `STRAIGHT_JOIN' also can be used in the
     TABLE_REFERENCES list. See *Note join::.

     `STRAIGHT_JOIN' does not apply to any table that the optimizer
     treats as a `const' or `system' table. Such a table produces a
     single row, is read during the optimization phase of query
     execution, and references to its columns are replaced with the
     appropriate column values before query execution proceeds. These
     tables will appear first in the query plan displayed by *Note
     `EXPLAIN': explain. See *Note using-explain::. This exception may
     not apply to `const' or `system' tables that are used on the
     `NULL'-complemented side of an outer join (that is, the right-side
     table of a `LEFT JOIN' or the left-side table of a `RIGHT JOIN'.

   * `SQL_BIG_RESULT' or `SQL_SMALL_RESULT' can be used with `GROUP BY'
     or `DISTINCT' to tell the optimizer that the result set has many
     rows or is small, respectively. For `SQL_BIG_RESULT', MySQL
     directly uses disk-based temporary tables if needed, and prefers
     sorting to using a temporary table with a key on the `GROUP BY'
     elements. For `SQL_SMALL_RESULT', MySQL uses fast temporary tables
     to store the resulting table instead of using sorting.  This
     should not normally be needed.

   * `SQL_BUFFER_RESULT' forces the result to be put into a temporary
     table. This helps MySQL free the table locks early and helps in
     cases where it takes a long time to send the result set to the
     client. This option can be used only for top-level *Note `SELECT':
     select.  statements, not for subqueries or following *Note
     `UNION': union.

   * `SQL_CALC_FOUND_ROWS' tells MySQL to calculate how many rows there
     would be in the result set, disregarding any `LIMIT' clause. The
     number of rows can then be retrieved with `SELECT FOUND_ROWS()'.
     See *Note information-functions::.

   * The `SQL_CACHE' and `SQL_NO_CACHE' options affect caching of query
     results in the query cache (see *Note query-cache::). `SQL_CACHE'
     tells MySQL to store the result in the query cache if it is
     cacheable and the value of the `query_cache_type' system variable
     is `2' or `DEMAND'.  `SQL_NO_CACHE' tells MySQL not to store the
     result in the query cache. For a query that uses *Note `UNION':
     union, subqueries, or views, the following rules apply:

        * `SQL_NO_CACHE' applies if it appears in any *Note `SELECT':
          select. in the query.

        * For a cacheable query, `SQL_CACHE' applies if it appears in
          the first *Note `SELECT': select. of the query, or in the
          first *Note `SELECT': select. of a view referred to by the
          query.


File: manual.info,  Node: select-into,  Next: join,  Prev: select,  Up: select

13.2.8.1 `SELECT ... INTO' Syntax
.................................

The *Note `SELECT ... INTO': select-into. form of *Note `SELECT':
select.  enables a query result to be written to a file or stored in
variables:

   * `SELECT ... INTO OUTFILE' writes the selected rows to a file.
     Column and line terminators can be specified to produce a specific
     output format.

   * `SELECT ... INTO DUMPFILE' writes a single row to a file without
     any formatting.

   * `SELECT ... INTO VAR_LIST' selects column values and into
     variables.

The *Note `SELECT': select. syntax description (see *Note select::)
shows the `INTO' clause near the end of the statement. It is also
possible to use `INTO' immediately following the SELECT_EXPR list.

The *Note `SELECT ... INTO OUTFILE 'FILE_NAME'': select-into. form of
*Note `SELECT': select. writes the selected rows to a file. The file is
created on the server host, so you must have the `FILE' privilege to use
this syntax. FILE_NAME cannot be an existing file, which among other
things prevents files such as `/etc/passwd' and database tables from
being destroyed. As of MySQL 5.0.19, the `character_set_filesystem'
system variable controls the interpretation of the file name.

The *Note `SELECT ... INTO OUTFILE': select-into. statement is intended
primarily to let you very quickly dump a table to a text file on the
server machine.  If you want to create the resulting file on some other
host than the server host, you normally cannot use *Note `SELECT ...
INTO OUTFILE': select-into. since there is no way to write a path to the
file relative to the server host's file system.

However, if the MySQL client software is installed on the remote
machine, you can instead use a client command such as `mysql -e "SELECT
..." > FILE_NAME' to generate the file on the client host.

It is also possible to create the resulting file on a different host
other than the server host, if the location of the file on the remote
host can be accessed using a network-mapped path on the server's file
system. In this case, the presence of *Note `mysql': mysql. (or some
other MySQL client program) is not required on the target host.

*Note `SELECT ... INTO OUTFILE': select-into. is the complement of
*Note `LOAD DATA INFILE': load-data. Column values are dumped using the
`binary' character set. In effect, there is no character set
conversion. If a table contains columns in several character sets, the
output data file will as well and you may not be able to reload the
file correctly.

The syntax for the EXPORT_OPTIONS part of the statement consists of the
same `FIELDS' and `LINES' clauses that are used with the *Note `LOAD
DATA INFILE': load-data. statement. See *Note load-data::, for
information about the `FIELDS' and `LINES' clauses, including their
default values and permissible values.

`FIELDS ESCAPED BY' controls how to write special characters. If the
`FIELDS ESCAPED BY' character is not empty, it is used as a prefix that
precedes following characters on output:

   * The `FIELDS ESCAPED BY' character

   * The `FIELDS [OPTIONALLY] ENCLOSED BY' character

   * The first character of the `FIELDS TERMINATED BY' and `LINES
     TERMINATED BY' values

   * ASCII `NUL' (the zero-valued byte; what is actually written
     following the escape character is ASCII ``0'', not a zero-valued
     byte)

The `FIELDS TERMINATED BY', `ENCLOSED BY', `ESCAPED BY', or `LINES
TERMINATED BY' characters _must_ be escaped so that you can read the
file back in reliably. ASCII `NUL' is escaped to make it easier to view
with some pagers.

The resulting file does not have to conform to SQL syntax, so nothing
else need be escaped.

If the `FIELDS ESCAPED BY' character is empty, no characters are
escaped and `NULL' is output as `NULL', not `\N'. It is probably not a
good idea to specify an empty escape character, particularly if field
values in your data contain any of the characters in the list just
given.

Here is an example that produces a file in the comma-separated values
(CSV) format used by many programs:

     SELECT a,b,a+b INTO OUTFILE '/tmp/result.txt'
       FIELDS TERMINATED BY ',' OPTIONALLY ENCLOSED BY '"'
       LINES TERMINATED BY '\n'
       FROM test_table;

If you use `INTO DUMPFILE' instead of `INTO OUTFILE', MySQL writes only
one row into the file, without any column or line termination and
without performing any escape processing. This is useful if you want to
store a *Note `BLOB': blob. value in a file.

*Note*:

Any file created by `INTO OUTFILE' or `INTO DUMPFILE' is writable by
all users on the server host. The reason for this is that the MySQL
server cannot create a file that is owned by anyone other than the user
under whose account it is running. (You should _never_ run *Note
`mysqld': mysqld. as `root' for this and other reasons.) The file thus
must be world-writable so that you can manipulate its contents.

If the `secure_file_priv' system variable is set to a nonempty
directory name, the file to be written must be located in that
directory.

The `INTO' clause can name a list of one or more variables, which can
be user-defined variables, stored procedure or function parameters, or
stored program local variables (see *Note stored-program-variables::).
The selected values are assigned to the variables. The number of
variables must match the number of columns. The query should return a
single row. If the query returns no rows, a warning with error code
1329 occurs (`No data'), and the variable values remain unchanged. If
the query returns multiple rows, error 1172 occurs (`Result consisted of
more than one row'). If it is possible that the statement may retrieve
multiple rows, you can use `LIMIT 1' to limit the result set to a
single row.

     SELECT id, data INTO @x, @y FROM test.t1 LIMIT 1;

User variable names are not case sensitive. See *Note user-variables::.

An `INTO' clause should not be used in a nested *Note `SELECT': select.
because such a *Note `SELECT': select. must return its result to the
outer context.


File: manual.info,  Node: join,  Next: index-hints,  Prev: select-into,  Up: select

13.2.8.2 `JOIN' Syntax
......................

MySQL supports the following `JOIN' syntaxes for the TABLE_REFERENCES
part of *Note `SELECT': select. statements and multiple-table *Note
`DELETE': delete. and *Note `UPDATE': update. statements:

     TABLE_REFERENCES:
         TABLE_REFERENCE [, TABLE_REFERENCE] ...

     TABLE_REFERENCE:
         TABLE_FACTOR
       | JOIN_TABLE

     TABLE_FACTOR:
         TBL_NAME [[AS] ALIAS] [INDEX_HINT]
       | TABLE_SUBQUERY [AS] ALIAS
       | ( TABLE_REFERENCES )
       | { OJ TABLE_REFERENCE LEFT OUTER JOIN TABLE_REFERENCE
             ON CONDITIONAL_EXPR }

     JOIN_TABLE:
         TABLE_REFERENCE [INNER | CROSS] JOIN TABLE_FACTOR [JOIN_CONDITION]
       | TABLE_REFERENCE STRAIGHT_JOIN TABLE_FACTOR
       | TABLE_REFERENCE STRAIGHT_JOIN TABLE_FACTOR ON CONDITIONAL_EXPR
       | TABLE_REFERENCE {LEFT|RIGHT} [OUTER] JOIN TABLE_REFERENCE JOIN_CONDITION
       | TABLE_REFERENCE NATURAL [{LEFT|RIGHT} [OUTER]] JOIN TABLE_FACTOR

     JOIN_CONDITION:
         ON CONDITIONAL_EXPR
       | USING (COLUMN_LIST)

     INDEX_HINT:
         USE {INDEX|KEY} [FOR JOIN] (INDEX_LIST)
       | IGNORE {INDEX|KEY} [FOR JOIN] (INDEX_LIST)
       | FORCE {INDEX|KEY} [FOR JOIN] (INDEX_LIST)

     INDEX_LIST:
         INDEX_NAME [, INDEX_NAME] ...

A table reference is also known as a join expression.

The syntax of TABLE_FACTOR is extended in comparison with the SQL
Standard. The latter accepts only TABLE_REFERENCE, not a list of them
inside a pair of parentheses.

This is a conservative extension if we consider each comma in a list of
TABLE_REFERENCE items as equivalent to an inner join. For example:

     SELECT * FROM t1 LEFT JOIN (t2, t3, t4)
                      ON (t2.a=t1.a AND t3.b=t1.b AND t4.c=t1.c)

is equivalent to:

     SELECT * FROM t1 LEFT JOIN (t2 CROSS JOIN t3 CROSS JOIN t4)
                      ON (t2.a=t1.a AND t3.b=t1.b AND t4.c=t1.c)

In MySQL, `CROSS JOIN' is a syntactic equivalent to `INNER JOIN' (they
can replace each other). In standard SQL, they are not equivalent.
`INNER JOIN' is used with an `ON' clause, `CROSS JOIN' is used
otherwise.

In versions of MySQL prior to 5.0.1, parentheses in TABLE_REFERENCES
were just omitted and all join operations were grouped to the left. In
general, parentheses can be ignored in join expressions containing only
inner join operations. As of 5.0.1, nested joins are permitted (see
*Note nested-join-optimization::).

Further changes in join processing were made in 5.0.12 to make MySQL
more compliant with standard SQL. These charges are described later in
this section.

Index hints can be specified to affect how the MySQL optimizer makes
use of indexes. For more information, see *Note index-hints::.

The following list describes general factors to take into account when
writing joins.

   * A table reference can be aliased using `TBL_NAME AS ALIAS_NAME' or
     TBL_NAME ALIAS_NAME:

          SELECT t1.name, t2.salary
            FROM employee AS t1 INNER JOIN info AS t2 ON t1.name = t2.name;

          SELECT t1.name, t2.salary
            FROM employee t1 INNER JOIN info t2 ON t1.name = t2.name;

   * A TABLE_SUBQUERY is also known as a subquery in the `FROM' clause.
     Such subqueries _must_ include an alias to give the subquery
     result a table name. A trivial example follows; see also *Note
     from-clause-subqueries::.

          SELECT * FROM (SELECT 1, 2, 3) AS t1;

   * `INNER JOIN' and `,' (comma) are semantically equivalent in the
     absence of a join condition: both produce a Cartesian product
     between the specified tables (that is, each and every row in the
     first table is joined to each and every row in the second table).

     However, the precedence of the comma operator is less than of
     `INNER JOIN', `CROSS JOIN', `LEFT JOIN', and so on. If you mix
     comma joins with the other join types when there is a join
     condition, an error of the form `Unknown column 'COL_NAME' in 'on
     clause'' may occur. Information about dealing with this problem is
     given later in this section.

   * The CONDITIONAL_EXPR used with `ON' is any conditional expression
     of the form that can be used in a `WHERE' clause.  Generally, you
     should use the `ON' clause for conditions that specify how to join
     tables, and the `WHERE' clause to restrict which rows you want in
     the result set.

   * If there is no matching row for the right table in the `ON' or
     `USING' part in a `LEFT JOIN', a row with all columns set to
     `NULL' is used for the right table. You can use this fact to find
     rows in a table that have no counterpart in another table:

          SELECT left_tbl.*
            FROM left_tbl LEFT JOIN right_tbl ON left_tbl.id = right_tbl.id
            WHERE right_tbl.id IS NULL;

     This example finds all rows in `left_tbl' with an `id' value that
     is not present in `right_tbl' (that is, all rows in `left_tbl'
     with no corresponding row in `right_tbl'). This assumes that
     `right_tbl.id' is declared `NOT NULL'. See *Note
     left-join-optimization::.

   * The `USING(COLUMN_LIST)' clause names a list of columns that must
     exist in both tables. If tables `a' and `b' both contain columns
     `c1', `c2', and `c3', the following join compares corresponding
     columns from the two tables:

          a LEFT JOIN b USING (c1,c2,c3)

   * The `NATURAL [LEFT] JOIN' of two tables is defined to be
     semantically equivalent to an `INNER JOIN' or a `LEFT JOIN' with a
     `USING' clause that names all columns that exist in both tables.

   * `RIGHT JOIN' works analogously to `LEFT JOIN'. To keep code
     portable across databases, it is recommended that you use `LEFT
     JOIN' instead of `RIGHT JOIN'.

   * The `{ OJ ... LEFT OUTER JOIN ...}' syntax shown in the join
     syntax description exists only for compatibility with ODBC. The
     curly braces in the syntax should be written literally; they are
     not metasyntax as used elsewhere in syntax descriptions.

          SELECT left_tbl.*
            FROM { OJ left_tbl LEFT OUTER JOIN right_tbl ON left_tbl.id = right_tbl.id }
            WHERE right_tbl.id IS NULL;

   * `STRAIGHT_JOIN' is similar to `JOIN', except that the left table is
     always read before the right table. This can be used for those
     (few) cases for which the join optimizer puts the tables in the
     wrong order.

Some join examples:

     SELECT * FROM table1, table2;

     SELECT * FROM table1 INNER JOIN table2 ON table1.id=table2.id;

     SELECT * FROM table1 LEFT JOIN table2 ON table1.id=table2.id;

     SELECT * FROM table1 LEFT JOIN table2 USING (id);

     SELECT * FROM table1 LEFT JOIN table2 ON table1.id=table2.id
       LEFT JOIN table3 ON table2.id=table3.id;

*Join Processing Changes in MySQL 5.0.12*

Beginning with MySQL 5.0.12, natural joins and joins with `USING',
including outer join variants, are processed according to the SQL:2003
standard. The goal was to align the syntax and semantics of MySQL with
respect to `NATURAL JOIN' and `JOIN ...  USING' according to SQL:2003.
However, these changes in join processing can result in different
output columns for some joins. Also, some queries that appeared to work
correctly in older versions must be rewritten to comply with the
standard.

These changes have five main aspects:

   * The way that MySQL determines the result columns of `NATURAL' or
     `USING' join operations (and thus the result of the entire `FROM'
     clause).

   * Expansion of `SELECT *' and `SELECT TBL_NAME.*' into a list of
     selected columns.

   * Resolution of column names in `NATURAL' or `USING' joins.

   * Transformation of `NATURAL' or `USING' joins into `JOIN ...  ON'.

   * Resolution of column names in the `ON' condition of a `JOIN ...
     ON'.

The following list provides more detail about several effects of the
5.0.12 change in join processing. The term `previously' means `prior to
MySQL 5.0.12.'

   * The columns of a `NATURAL' join or a `USING' join may be different
     from previously. Specifically, redundant output columns no longer
     appear, and the order of columns for `SELECT *' expansion may be
     different from before.

     Consider this set of statements:

          CREATE TABLE t1 (i INT, j INT);
          CREATE TABLE t2 (k INT, j INT);
          INSERT INTO t1 VALUES(1,1);
          INSERT INTO t2 VALUES(1,1);
          SELECT * FROM t1 NATURAL JOIN t2;
          SELECT * FROM t1 JOIN t2 USING (j);

     Previously, the statements produced this output:

          +------+------+------+------+
          | i    | j    | k    | j    |
          +------+------+------+------+
          |    1 |    1 |    1 |    1 |
          +------+------+------+------+
          +------+------+------+------+
          | i    | j    | k    | j    |
          +------+------+------+------+
          |    1 |    1 |    1 |    1 |
          +------+------+------+------+

     In the first *Note `SELECT': select.  statement, column `j'
     appears in both tables and thus becomes a join column, so,
     according to standard SQL, it should appear only once in the
     output, not twice. Similarly, in the second SELECT statement,
     column `j' is named in the `USING' clause and should appear only
     once in the output, not twice. But in both cases, the redundant
     column is not eliminated. Also, the order of the columns is not
     correct according to standard SQL.

     Now the statements produce this output:

          +------+------+------+
          | j    | i    | k    |
          +------+------+------+
          |    1 |    1 |    1 |
          +------+------+------+
          +------+------+------+
          | j    | i    | k    |
          +------+------+------+
          |    1 |    1 |    1 |
          +------+------+------+

     The redundant column is eliminated and the column order is correct
     according to standard SQL:

        * First, coalesced common columns of the two joined tables, in
          the order in which they occur in the first table

        * Second, columns unique to the first table, in order in which
          they occur in that table

        * Third, columns unique to the second table, in order in which
          they occur in that table

     The single result column that replaces two common columns is
     defined using the coalesce operation. That is, for two `t1.a' and
     `t2.a' the resulting single join column `a' is defined as `a =
     COALESCE(t1.a, t2.a)', where:

          COALESCE(x, y) = (CASE WHEN V1 IS NOT NULL THEN V1 ELSE V2 END)

     If the join operation is any other join, the result columns of the
     join consists of the concatenation of all columns of the joined
     tables. This is the same as previously.

     A consequence of the definition of coalesced columns is that, for
     outer joins, the coalesced column contains the value of the
     non-`NULL' column if one of the two columns is always `NULL'. If
     neither or both columns are `NULL', both common columns have the
     same value, so it doesn't matter which one is chosen as the value
     of the coalesced column. A simple way to interpret this is to
     consider that a coalesced column of an outer join is represented
     by the common column of the inner table of a `JOIN'. Suppose that
     the tables `t1(a,b)' and `t2(a,c)' have the following contents:

          t1    t2
          ----  ----
          1 x   2 z
          2 y   3 w

     Then:

          mysql> SELECT * FROM t1 NATURAL LEFT JOIN t2;
          +------+------+------+
          | a    | b    | c    |
          +------+------+------+
          |    1 | x    | NULL |
          |    2 | y    | z    |
          +------+------+------+

     Here column `a' contains the values of `t1.a'.

          mysql> SELECT * FROM t1 NATURAL RIGHT JOIN t2;
          +------+------+------+
          | a    | c    | b    |
          +------+------+------+
          |    2 | z    | y    |
          |    3 | w    | NULL |
          +------+------+------+

     Here column `a' contains the values of `t2.a'.

     Compare these results to the otherwise equivalent queries with
     `JOIN ... ON':

          mysql> SELECT * FROM t1 LEFT JOIN t2 ON (t1.a = t2.a);
          +------+------+------+------+
          | a    | b    | a    | c    |
          +------+------+------+------+
          |    1 | x    | NULL | NULL |
          |    2 | y    |    2 | z    |
          +------+------+------+------+

          mysql> SELECT * FROM t1 RIGHT JOIN t2 ON (t1.a = t2.a);
          +------+------+------+------+
          | a    | b    | a    | c    |
          +------+------+------+------+
          |    2 | y    |    2 | z    |
          | NULL | NULL |    3 | w    |
          +------+------+------+------+

   * Previously, a `USING' clause could be rewritten as an `ON' clause
     that compares corresponding columns. For example, the following two
     clauses were semantically identical:

          a LEFT JOIN b USING (c1,c2,c3)
          a LEFT JOIN b ON a.c1=b.c1 AND a.c2=b.c2 AND a.c3=b.c3

     Now the two clauses no longer are quite the same:

        * With respect to determining which rows satisfy the join
          condition, both joins remain semantically identical.

        * With respect to determining which columns to display for
          `SELECT *' expansion, the two joins are not semantically
          identical. The `USING' join selects the coalesced value of
          corresponding columns, whereas the `ON' join selects all
          columns from all tables. For the preceding `USING' join,
          `SELECT *' selects these values:

               COALESCE(a.c1,b.c1), COALESCE(a.c2,b.c2), COALESCE(a.c3,b.c3)

          For the `ON' join, `SELECT *' selects these values:

               a.c1, a.c2, a.c3, b.c1, b.c2, b.c3

          With an inner join, `COALESCE(a.c1,b.c1)' is the same as
          either `a.c1' or `b.c1' because both columns will have the
          same value. With an outer join (such as `LEFT JOIN'), one of
          the two columns can be `NULL'. That column will be omitted
          from the result.

   * The evaluation of multi-way natural joins differs in a very
     important way that affects the result of `NATURAL' or `USING' joins
     and that can require query rewriting. Suppose that you have three
     tables `t1(a,b)', `t2(c,b)', and `t3(a,c)' that each have one row:
     `t1(1,2)', `t2(10,2)', and `t3(7,10)'. Suppose also that you have
     this `NATURAL JOIN' on the three tables:

          SELECT ... FROM t1 NATURAL JOIN t2 NATURAL JOIN t3;

     Previously, the left operand of the second join was considered to
     be `t2', whereas it should be the nested join `(t1 NATURAL JOIN
     t2)'. As a result, the columns of `t3' are checked for common
     columns only in `t2', and, if `t3' has common columns with `t1',
     these columns are not used as equi-join columns. Thus, previously,
     the preceding query was transformed to the following equi-join:

          SELECT ... FROM t1, t2, t3
            WHERE t1.b = t2.b AND t2.c = t3.c;

     That join is missing one more equi-join predicate `(t1.a = t3.a)'.
     As a result, it produces one row, not the empty result that it
     should. The correct equivalent query is this:

          SELECT ... FROM t1, t2, t3
            WHERE t1.b = t2.b AND t2.c = t3.c AND t1.a = t3.a;

     If you require the same query result in current versions of MySQL
     as in older versions, rewrite the natural join as the first
     equi-join.

   * Previously, the comma operator (`,') and `JOIN' both had the same
     precedence, so the join expression `t1, t2 JOIN t3' was
     interpreted as `((t1, t2) JOIN t3)'. Now `JOIN' has higher
     precedence, so the expression is interpreted as `(t1, (t2 JOIN
     t3))'. This change affects statements that use an `ON' clause,
     because that clause can refer only to columns in the operands of
     the join, and the change in precedence changes interpretation of
     what those operands are.

     Example:

          CREATE TABLE t1 (i1 INT, j1 INT);
          CREATE TABLE t2 (i2 INT, j2 INT);
          CREATE TABLE t3 (i3 INT, j3 INT);
          INSERT INTO t1 VALUES(1,1);
          INSERT INTO t2 VALUES(1,1);
          INSERT INTO t3 VALUES(1,1);
          SELECT * FROM t1, t2 JOIN t3 ON (t1.i1 = t3.i3);

     Previously, the *Note `SELECT': select. was legal due to the
     implicit grouping of `t1,t2' as `(t1,t2)'. Now the `JOIN' takes
     precedence, so the operands for the `ON' clause are `t2' and `t3'.
     Because `t1.i1' is not a column in either of the operands, the
     result is an `Unknown column 't1.i1' in 'on clause'' error. To
     allow the join to be processed, group the first two tables
     explicitly with parentheses so that the operands for the `ON'
     clause are `(t1,t2)' and `t3':

          SELECT * FROM (t1, t2) JOIN t3 ON (t1.i1 = t3.i3);

     Alternatively, avoid the use of the comma operator and use `JOIN'
     instead:

          SELECT * FROM t1 JOIN t2 JOIN t3 ON (t1.i1 = t3.i3);

     This change also applies to statements that mix the comma operator
     with `INNER JOIN', `CROSS JOIN', `LEFT JOIN', and `RIGHT JOIN',
     all of which now have higher precedence than the comma operator.

   * Previously, the `ON' clause could refer to columns in tables named
     to its right. Now an `ON' clause can refer only to its operands.

     Example:

          CREATE TABLE t1 (i1 INT);
          CREATE TABLE t2 (i2 INT);
          CREATE TABLE t3 (i3 INT);
          SELECT * FROM t1 JOIN t2 ON (i1 = i3) JOIN t3;

     Previously, the *Note `SELECT': select.  statement was legal. Now
     the statement fails with an `Unknown column 'i3' in 'on clause''
     error because `i3' is a column in `t3', which is not an operand of
     the `ON' clause. The statement should be rewritten as follows:

          SELECT * FROM t1 JOIN t2 JOIN t3 ON (i1 = i3);

   * Resolution of column names in `NATURAL' or `USING' joins is
     different than previously.  For column names that are outside the
     `FROM' clause, MySQL now handles a superset of the queries
     compared to previously. That is, in cases when MySQL formerly
     issued an error that some column is ambiguous, the query now is
     handled correctly. This is due to the fact that MySQL now treats
     the common columns of `NATURAL' or `USING' joins as a single
     column, so when a query refers to such columns, the query compiler
     does not consider them as ambiguous.

     Example:

          SELECT * FROM t1 NATURAL JOIN t2 WHERE b > 1;

     Previously, this query would produce an error `ERROR 1052 (23000):
     Column 'b' in where clause is ambiguous'. Now the query produces
     the correct result:

          +------+------+------+
          | b    | c    | y    |
          +------+------+------+
          |    4 |    2 |    3 |
          +------+------+------+

     One extension of MySQL compared to the SQL:2003 standard is that
     MySQL enables you to qualify the common (coalesced) columns of
     `NATURAL' or `USING' joins (just as previously), while the
     standard disallows that.


File: manual.info,  Node: index-hints,  Next: union,  Prev: join,  Up: select

13.2.8.3 Index Hint Syntax
..........................

You can provide hints to give the optimizer information about how to
choose indexes during query processing.  *Note join::, describes the
general syntax for specifying tables in a *Note `SELECT': select.
statement. The syntax for an individual table, including that for index
hints, looks like this:

     TBL_NAME [[AS] ALIAS] [INDEX_HINT]

     INDEX_HINT:
         USE {INDEX|KEY} [FOR JOIN] (INDEX_LIST)
       | IGNORE {INDEX|KEY} [FOR JOIN] (INDEX_LIST)
       | FORCE {INDEX|KEY} [FOR JOIN] (INDEX_LIST)

     INDEX_LIST:
         INDEX_NAME [, INDEX_NAME] ...

By specifying `USE INDEX (INDEX_LIST)', you can tell MySQL to use only
one of the named indexes to find rows in the table. The alternative
syntax `IGNORE INDEX (INDEX_LIST)' can be used to tell MySQL to not use
some particular index or indexes. These hints are useful if *Note
`EXPLAIN': explain. shows that MySQL is using the wrong index from the
list of possible indexes.

You can also use `FORCE INDEX', which acts like `USE INDEX
(INDEX_LIST)' but with the addition that a table scan is assumed to be
_very_ expensive. In other words, a table scan is used only if there is
no way to use one of the given indexes to find rows in the table.

Each hint requires the names of _indexes_, not the names of columns.
The name of a `PRIMARY KEY' is `PRIMARY'. To see the index names for a
table, use *Note `SHOW INDEX': show-index.

An INDEX_NAME value need not be a full index name. It can be an
unambiguous prefix of an index name. If a prefix is ambiguous, an error
occurs.

`USE INDEX', `IGNORE INDEX', and `FORCE INDEX' affect only which
indexes are used when MySQL decides how to find rows in the table and
how to do the join. They do not affect whether an index is used when
resolving an `ORDER BY' or `GROUP BY' clause. As of MySQL 5.0.40, the
optional `FOR JOIN' clause can be added to make this explicit.

Examples:

     SELECT * FROM table1 USE INDEX (col1_index,col2_index)
       WHERE col1=1 AND col2=2 AND col3=3;

     SELECT * FROM table1 IGNORE INDEX (col3_index)
       WHERE col1=1 AND col2=2 AND col3=3;

For `FULLTEXT' searches, index hints do not work before MySQL 5.0.74.
As of 5.0.74, index hints work as follows:

   * For natural language mode searches, index hints are silently
     ignored. For example, `IGNORE INDEX(i)' is ignored with no warning
     and the index is still used.

     For boolean mode searches, index hints are honored.

Index hints are accepted but ignored for *Note `UPDATE': update.
statements.


File: manual.info,  Node: union,  Prev: index-hints,  Up: select

13.2.8.4 `UNION' Syntax
.......................

     SELECT ...
     UNION [ALL | DISTINCT] SELECT ...
     [UNION [ALL | DISTINCT] SELECT ...]

*Note `UNION': union. is used to combine the result from multiple *Note
`SELECT': select.  statements into a single result set.

The column names from the first *Note `SELECT': select. statement are
used as the column names for the results returned. Selected columns
listed in corresponding positions of each *Note `SELECT': select.
statement should have the same data type. (For example, the first
column selected by the first statement should have the same type as the
first column selected by the other statements.)

If the data types of corresponding *Note `SELECT': select. columns do
not match, the types and lengths of the columns in the *Note `UNION':
union. result take into account the values retrieved by all of the
*Note `SELECT': select. statements. For example, consider the following:

     mysql> SELECT REPEAT('a',1) UNION SELECT REPEAT('b',10);
     +---------------+
     | REPEAT('a',1) |
     +---------------+
     | a             |
     | bbbbbbbbbb    |
     +---------------+

(In some earlier versions of MySQL, only the type and length from the
first *Note `SELECT': select. would have been used and the second row
would have been truncated to a length of 1.)

The *Note `SELECT': select. statements are normal select statements,
but with the following restrictions:

   * Only the last *Note `SELECT': select.  statement can use `INTO
     OUTFILE'. (However, the entire *Note `UNION': union. result is
     written to the file.)

   * `HIGH_PRIORITY' cannot be used with *Note `SELECT': select.
     statements that are part of a *Note `UNION': union. If you specify
     it for the first *Note `SELECT': select, it has no effect. If you
     specify it for any subsequent *Note `SELECT': select. statements,
     a syntax error results.

The default behavior for *Note `UNION': union. is that duplicate rows
are removed from the result. The optional `DISTINCT' keyword has no
effect other than the default because it also specifies duplicate-row
removal. With the optional `ALL' keyword, duplicate-row removal does
not occur and the result includes all matching rows from all the *Note
`SELECT': select. statements.

You can mix *Note `UNION ALL': union. and *Note `UNION DISTINCT':
union. in the same query. Mixed *Note `UNION': union. types are treated
such that a `DISTINCT' union overrides any `ALL' union to its left. A
`DISTINCT' union can be produced explicitly by using *Note `UNION
DISTINCT': union. or implicitly by using *Note `UNION': union. with no
following `DISTINCT' or `ALL' keyword.

To apply `ORDER BY' or `LIMIT' to an individual *Note `SELECT': select,
place the clause inside the parentheses that enclose the *Note
`SELECT': select.:

     (SELECT a FROM t1 WHERE a=10 AND B=1 ORDER BY a LIMIT 10)
     UNION
     (SELECT a FROM t2 WHERE a=11 AND B=2 ORDER BY a LIMIT 10);

However, use of `ORDER BY' for individual *Note `SELECT': select.
statements implies nothing about the order in which the rows appear in
the final result because *Note `UNION': union. by default produces an
unordered set of rows. Therefore, the use of `ORDER BY' in this context
is typically in conjunction with `LIMIT', so that it is used to
determine the subset of the selected rows to retrieve for the *Note
`SELECT': select, even though it does not necessarily affect the order
of those rows in the final *Note `UNION': union. result. If `ORDER BY'
appears without `LIMIT' in a *Note `SELECT': select, it is optimized
away because it will have no effect anyway.

To use an `ORDER BY' or `LIMIT' clause to sort or limit the entire
*Note `UNION': union. result, parenthesize the individual *Note
`SELECT': select. statements and place the `ORDER BY' or `LIMIT' after
the last one. The following example uses both clauses:

     (SELECT a FROM t1 WHERE a=10 AND B=1)
     UNION
     (SELECT a FROM t2 WHERE a=11 AND B=2)
     ORDER BY a LIMIT 10;

A statement without parentheses is equivalent to one parenthesized as
just shown.

This kind of `ORDER BY' cannot use column references that include a
table name (that is, names in TBL_NAME.COL_NAME format). Instead,
provide a column alias in the first *Note `SELECT': select. statement
and refer to the alias in the `ORDER BY'. (Alternatively, refer to the
column in the `ORDER BY' using its column position. However, use of
column positions is deprecated.)

Also, if a column to be sorted is aliased, the `ORDER BY' clause _must_
refer to the alias, not the column name. The first of the following
statements will work, but the second will fail with an `Unknown column
'a' in 'order clause'' error:

     (SELECT a AS b FROM t) UNION (SELECT ...) ORDER BY b;
     (SELECT a AS b FROM t) UNION (SELECT ...) ORDER BY a;

To cause rows in a *Note `UNION': union. result to consist of the sets
of rows retrieved by each *Note `SELECT': select. one after the other,
select an additional column in each *Note `SELECT': select. to use as a
sort column and add an `ORDER BY' following the last *Note `SELECT':
select.:

     (SELECT 1 AS sort_col, col1a, col1b, ... FROM t1)
     UNION
     (SELECT 2, col2a, col2b, ... FROM t2) ORDER BY sort_col;

To additionally maintain sort order within individual *Note `SELECT':
select. results, add a secondary column to the `ORDER BY' clause:

     (SELECT 1 AS sort_col, col1a, col1b, ... FROM t1)
     UNION
     (SELECT 2, col2a, col2b, ... FROM t2) ORDER BY sort_col, col1a;

Use of an additional column also enables you to determine which *Note
`SELECT': select. each row comes from. Extra columns can provide other
identifying information as well, such as a string that indicates a
table name.


File: manual.info,  Node: subqueries,  Next: update,  Prev: select,  Up: sql-syntax-data-manipulation

13.2.9 Subquery Syntax
----------------------

* Menu:

* scalar-subqueries::            The Subquery as Scalar Operand
* comparisons-using-subqueries::  Comparisons Using Subqueries
* any-in-some-subqueries::       Subqueries with `ANY', `IN', or `SOME'
* all-subqueries::               Subqueries with `ALL'
* row-subqueries::               Row Subqueries
* exists-and-not-exists-subqueries::  Subqueries with `EXISTS' or `NOT EXISTS'
* correlated-subqueries::        Correlated Subqueries
* from-clause-subqueries::       Subqueries in the `FROM' Clause
* subquery-errors::              Subquery Errors
* optimizing-subqueries::        Optimizing Subqueries
* rewriting-subqueries::         Rewriting Subqueries as Joins

A subquery is a *Note `SELECT': select. statement within another
statement.

Starting with MySQL 4.1, all subquery forms and operations that the SQL
standard requires are supported, as well as a few features that are
MySQL-specific.

Here is an example of a subquery:

     SELECT * FROM t1 WHERE column1 = (SELECT column1 FROM t2);

In this example, `SELECT * FROM t1 ...' is the _outer query_ (or _outer
statement_), and `(SELECT column1 FROM t2)' is the _subquery_. We say
that the subquery is _nested_ within the outer query, and in fact it is
possible to nest subqueries within other subqueries, to a considerable
depth. A subquery must always appear within parentheses.

The main advantages of subqueries are:

   * They allow queries that are _structured_ so that it is possible to
     isolate each part of a statement.

   * They provide alternative ways to perform operations that would
     otherwise require complex joins and unions.

   * Many people find subqueries more readable than complex joins or
     unions. Indeed, it was the innovation of subqueries that gave
     people the original idea of calling the early SQL `Structured
     Query Language.'

Here is an example statement that shows the major points about subquery
syntax as specified by the SQL standard and supported in MySQL:

     DELETE FROM t1
     WHERE s11 > ANY
      (SELECT COUNT(*) /* no hint */ FROM t2
       WHERE NOT EXISTS
        (SELECT * FROM t3
         WHERE ROW(5*t2.s1,77)=
          (SELECT 50,11*s1 FROM t4 UNION SELECT 50,77 FROM
           (SELECT * FROM t5) AS t5)));

A subquery can return a scalar (a single value), a single row, a single
column, or a table (one or more rows of one or more columns). These are
called scalar, column, row, and table subqueries. Subqueries that
return a particular kind of result often can be used only in certain
contexts, as described in the following sections.

There are few restrictions on the type of statements in which
subqueries can be used. A subquery can contain many of the keywords or
clauses that an ordinary *Note `SELECT': select. can contain:
`DISTINCT', `GROUP BY', `ORDER BY', `LIMIT', joins, index hints, *Note
`UNION': union. constructs, comments, functions, and so on.

One restriction is that a subquery's outer statement must be one of:
*Note `SELECT': select, *Note `INSERT': insert, *Note `UPDATE': update,
*Note `DELETE': delete, *Note `SET': set-option, or *Note `DO': do.
Another restriction is that currently you cannot modify a table and
select from the same table in a subquery. This applies to statements
such as *Note `DELETE': delete, *Note `INSERT': insert, *Note
`REPLACE': replace, *Note `UPDATE': update, and (because subqueries can
be used in the `SET' clause) *Note `LOAD DATA INFILE': load-data.

A more comprehensive discussion of restrictions on subquery use,
including performance issues for certain forms of subquery syntax, is
given in *Note subquery-restrictions::.


File: manual.info,  Node: scalar-subqueries,  Next: comparisons-using-subqueries,  Prev: subqueries,  Up: subqueries

13.2.9.1 The Subquery as Scalar Operand
.......................................

In its simplest form, a subquery is a scalar subquery that returns a
single value. A scalar subquery is a simple operand, and you can use it
almost anywhere a single column value or literal is legal, and you can
expect it to have those characteristics that all operands have: a data
type, a length, an indication that it can be `NULL', and so on.  For
example:

     CREATE TABLE t1 (s1 INT, s2 CHAR(5) NOT NULL);
     INSERT INTO t1 VALUES(100, 'abcde');
     SELECT (SELECT s2 FROM t1);

The subquery in this *Note `SELECT': select.  returns a single value
(`'abcde'') that has a data type of *Note `CHAR': char, a length of 5,
a character set and collation equal to the defaults in effect at *Note
`CREATE TABLE': create-table. time, and an indication that the value in
the column can be `NULL'. Nullability of the value selected by a scalar
subquery is not copied because if the subquery result is empty, the
result is `NULL'. For the subquery just shown, if `t1' were empty, the
result would be `NULL' even though `s2' is `NOT NULL'.

There are a few contexts in which a scalar subquery cannot be used. If
a statement permits only a literal value, you cannot use a subquery.
For example, `LIMIT' requires literal integer arguments, and *Note
`LOAD DATA INFILE': load-data. requires a literal string file name. You
cannot use subqueries to supply these values.

When you see examples in the following sections that contain the rather
spartan construct `(SELECT column1 FROM t1)', imagine that your own
code contains much more diverse and complex constructions.

Suppose that we make two tables:

     CREATE TABLE t1 (s1 INT);
     INSERT INTO t1 VALUES (1);
     CREATE TABLE t2 (s1 INT);
     INSERT INTO t2 VALUES (2);

Then perform a *Note `SELECT': select.:

     SELECT (SELECT s1 FROM t2) FROM t1;

The result is `2' because there is a row in `t2' containing a column
`s1' that has a value of `2'.

A scalar subquery can be part of an expression, but remember the
parentheses, even if the subquery is an operand that provides an
argument for a function. For example:

     SELECT UPPER((SELECT s1 FROM t1)) FROM t2;


File: manual.info,  Node: comparisons-using-subqueries,  Next: any-in-some-subqueries,  Prev: scalar-subqueries,  Up: subqueries

13.2.9.2 Comparisons Using Subqueries
.....................................

The most common use of a subquery is in the form:

     NON_SUBQUERY_OPERAND COMPARISON_OPERATOR (SUBQUERY)

Where COMPARISON_OPERATOR is one of these operators:

     =  >  <  >=  <=  <>  !=  <=>

For example:

     ... WHERE 'a' = (SELECT column1 FROM t1)

MySQL also permits this construct:

     NON_SUBQUERY_OPERAND LIKE (SUBQUERY)

At one time the only legal place for a subquery was on the right side
of a comparison, and you might still find some old DBMSs that insist on
this.

Here is an example of a common-form subquery comparison that you cannot
do with a join. It finds all the rows in table `t1' for which the
`column1' value is equal to a maximum value in table `t2':

     SELECT * FROM t1
       WHERE column1 = (SELECT MAX(column2) FROM t2);

Here is another example, which again is impossible with a join because
it involves aggregating for one of the tables. It finds all rows in
table `t1' containing a value that occurs twice in a given column:

     SELECT * FROM t1 AS t
       WHERE 2 = (SELECT COUNT(*) FROM t1 WHERE t1.id = t.id);

For a comparison of the subquery to a scalar, the subquery must return
a scalar. For a comparison of the subquery to a row constructor, the
subquery must be a row subquery that returns a row with the same number
of values as the row constructor. See *Note row-subqueries::.


File: manual.info,  Node: any-in-some-subqueries,  Next: all-subqueries,  Prev: comparisons-using-subqueries,  Up: subqueries

13.2.9.3 Subqueries with `ANY', `IN', or `SOME'
...............................................

Syntax:

     OPERAND COMPARISON_OPERATOR ANY (SUBQUERY)
     OPERAND IN (SUBQUERY)
     OPERAND COMPARISON_OPERATOR SOME (SUBQUERY)

Where COMPARISON_OPERATOR is one of these operators:

     =  >  <  >=  <=  <>  !=

The `ANY' keyword, which must follow a comparison operator, means
`return `TRUE' if the comparison is `TRUE' for `ANY' of the values in
the column that the subquery returns.' For example:

     SELECT s1 FROM t1 WHERE s1 > ANY (SELECT s1 FROM t2);

Suppose that there is a row in table `t1' containing `(10)'. The
expression is `TRUE' if table `t2' contains `(21,14,7)' because there
is a value `7' in `t2' that is less than `10'. The expression is
`FALSE' if table `t2' contains `(20,10)', or if table `t2' is empty.
The expression is _unknown_ (that is, `NULL') if table `t2' contains
`(NULL,NULL,NULL)'.

When used with a subquery, the word `IN' is an alias for `= ANY'. Thus,
these two statements are the same:

     SELECT s1 FROM t1 WHERE s1 = ANY (SELECT s1 FROM t2);
     SELECT s1 FROM t1 WHERE s1 IN    (SELECT s1 FROM t2);

`IN' and `= ANY' are not synonyms when used with an expression list.
`IN' can take an expression list, but `= ANY' cannot. See *Note
comparison-operators::.

`NOT IN' is not an alias for `<> ANY', but for `<> ALL'. See *Note
all-subqueries::.

The word `SOME' is an alias for `ANY'. Thus, these two statements are
the same:

     SELECT s1 FROM t1 WHERE s1 <> ANY  (SELECT s1 FROM t2);
     SELECT s1 FROM t1 WHERE s1 <> SOME (SELECT s1 FROM t2);

Use of the word `SOME' is rare, but this example shows why it might be
useful. To most people, the English phrase `a is not equal to any b'
means `there is no b which is equal to a,' but that is not what is
meant by the SQL syntax. The syntax means `there is some b to which a
is not equal.' Using `<> SOME' instead helps ensure that everyone
understands the true meaning of the query.


File: manual.info,  Node: all-subqueries,  Next: row-subqueries,  Prev: any-in-some-subqueries,  Up: subqueries

13.2.9.4 Subqueries with `ALL'
..............................

Syntax:

     OPERAND COMPARISON_OPERATOR ALL (SUBQUERY)

The word `ALL', which must follow a comparison operator, means `return
`TRUE' if the comparison is `TRUE' for `ALL' of the values in the
column that the subquery returns.' For example:

     SELECT s1 FROM t1 WHERE s1 > ALL (SELECT s1 FROM t2);

Suppose that there is a row in table `t1' containing `(10)'. The
expression is `TRUE' if table `t2' contains `(-5,0,+5)' because `10' is
greater than all three values in `t2'. The expression is `FALSE' if
table `t2' contains `(12,6,NULL,-100)' because there is a single value
`12' in table `t2' that is greater than `10'. The expression is
_unknown_ (that is, `NULL') if table `t2' contains `(0,NULL,1)'.

Finally, the expression is `TRUE' if table `t2' is empty. So, the
following expression is `TRUE' when table `t2' is empty:

     SELECT * FROM t1 WHERE 1 > ALL (SELECT s1 FROM t2);

But this expression is `NULL' when table `t2' is empty:

     SELECT * FROM t1 WHERE 1 > (SELECT s1 FROM t2);

In addition, the following expression is `NULL' when table `t2' is
empty:

     SELECT * FROM t1 WHERE 1 > ALL (SELECT MAX(s1) FROM t2);

In general, _tables containing `NULL' values_ and _empty tables_ are
`edge cases.' When writing subqueries, always consider whether you have
taken those two possibilities into account.

`NOT IN' is an alias for `<> ALL'. Thus, these two statements are the
same:

     SELECT s1 FROM t1 WHERE s1 <> ALL (SELECT s1 FROM t2);
     SELECT s1 FROM t1 WHERE s1 NOT IN (SELECT s1 FROM t2);


File: manual.info,  Node: row-subqueries,  Next: exists-and-not-exists-subqueries,  Prev: all-subqueries,  Up: subqueries

13.2.9.5 Row Subqueries
.......................

The discussion to this point has been of scalar or column subqueries;
that is, subqueries that return a single value or a column of values. A
_row subquery_ is a subquery variant that returns a single row and can
thus return more than one column value. Legal operators for row subquery
comparisons are:

     =  >  <  >=  <=  <>  !=  <=>

Here are two examples:

     SELECT * FROM t1
       WHERE (col1,col2) = (SELECT col3, col4 FROM t2 WHERE id = 10);
     SELECT * FROM t1
       WHERE ROW(col1,col2) = (SELECT col3, col4 FROM t2 WHERE id = 10);

For both queries, if the table `t2' contains a single row with `id =
10', the subquery returns a single row. If this row has `col3' and
`col4' values equal to the `col1' and `col2' values of any rows in
`t1', the `WHERE' expression is `TRUE' and each query returns those
`t1' rows. If the `t2' row `col3' and `col4' values are not equal the
`col1' and `col2' values of any `t1' row, the expression is `FALSE' and
the query returns an empty result set. The expression is _unknown_
(that is, `NULL') if the subquery produces no rows. An error occurs if
the subquery produces multiple rows because a row subquery can return
at most one row.

The expressions `(1,2)' and `ROW(1,2)' are sometimes called _row
constructors_. The two are equivalent. The row constructor and the row
returned by the subquery must contain the same number of values.

A row constructor is used for comparisons with subqueries that return
two or more columns. When a subquery returns a single column, this is
regarded as a scalar value and not as a row, so a row constructor
cannot be used with a subquery that does not return at least two
columns. Thus, the following query fails with a syntax error:

     SELECT * FROM t1 WHERE ROW(1) = (SELECT column1 FROM t2)

Row constructors are legal in other contexts. For example, the
following two statements are semantically equivalent:

     SELECT * FROM t1 WHERE (column1,column2) = (1,1);
     SELECT * FROM t1 WHERE column1 = 1 AND column2 = 1;

Prior to MySQL 5.0.26, only the second of the preceding two expressions
could be optimized. (Bug #16081)

The following query answers the request, `find all rows in table `t1'
that also exist in table `t2'':

     SELECT column1,column2,column3
       FROM t1
       WHERE (column1,column2,column3) IN
              (SELECT column1,column2,column3 FROM t2);


File: manual.info,  Node: exists-and-not-exists-subqueries,  Next: correlated-subqueries,  Prev: row-subqueries,  Up: subqueries

13.2.9.6 Subqueries with `EXISTS' or `NOT EXISTS'
.................................................

If a subquery returns any rows at all, `EXISTS SUBQUERY' is `TRUE', and
`NOT EXISTS SUBQUERY' is `FALSE'. For example:

     SELECT column1 FROM t1 WHERE EXISTS (SELECT * FROM t2);

Traditionally, an `EXISTS' subquery starts with `SELECT *', but it
could begin with `SELECT 5' or `SELECT column1' or anything at all.
MySQL ignores the *Note `SELECT': select. list in such a subquery, so
it makes no difference.

For the preceding example, if `t2' contains any rows, even rows with
nothing but `NULL' values, the `EXISTS' condition is `TRUE'. This is
actually an unlikely example because a `[NOT] EXISTS' subquery almost
always contains correlations. Here are some more realistic examples:

   * What kind of store is present in one or more cities?

          SELECT DISTINCT store_type FROM stores
            WHERE EXISTS (SELECT * FROM cities_stores
                          WHERE cities_stores.store_type = stores.store_type);

   * What kind of store is present in no cities?

          SELECT DISTINCT store_type FROM stores
            WHERE NOT EXISTS (SELECT * FROM cities_stores
                              WHERE cities_stores.store_type = stores.store_type);

   * What kind of store is present in all cities?

          SELECT DISTINCT store_type FROM stores s1
            WHERE NOT EXISTS (
              SELECT * FROM cities WHERE NOT EXISTS (
                SELECT * FROM cities_stores
                 WHERE cities_stores.city = cities.city
                 AND cities_stores.store_type = stores.store_type));

The last example is a double-nested `NOT EXISTS' query. That is, it has
a `NOT EXISTS' clause within a `NOT EXISTS' clause. Formally, it
answers the question `does a city exist with a store that is not in
`Stores''? But it is easier to say that a nested `NOT EXISTS' answers
the question `is X `TRUE' for all Y?'


File: manual.info,  Node: correlated-subqueries,  Next: from-clause-subqueries,  Prev: exists-and-not-exists-subqueries,  Up: subqueries

13.2.9.7 Correlated Subqueries
..............................

A _correlated subquery_ is a subquery that contains a reference to a
table that also appears in the outer query. For example:

     SELECT * FROM t1
       WHERE column1 = ANY (SELECT column1 FROM t2
                            WHERE t2.column2 = t1.column2);

Notice that the subquery contains a reference to a column of `t1', even
though the subquery's `FROM' clause does not mention a table `t1'. So,
MySQL looks outside the subquery, and finds `t1' in the outer query.

Suppose that table `t1' contains a row where `column1 = 5' and `column2
= 6'; meanwhile, table `t2' contains a row where `column1 = 5' and
`column2 = 7'. The simple expression `... WHERE column1 = ANY (SELECT
column1 FROM t2)' would be `TRUE', but in this example, the `WHERE'
clause within the subquery is `FALSE' (because `(5,6)' is not equal to
`(5,7)'), so the expression as a whole is `FALSE'.

*Scoping rule:* MySQL evaluates from inside to outside. For example:

     SELECT column1 FROM t1 AS x
       WHERE x.column1 = (SELECT column1 FROM t2 AS x
         WHERE x.column1 = (SELECT column1 FROM t3
           WHERE x.column2 = t3.column1));

In this statement, `x.column2' must be a column in table `t2' because
`SELECT column1 FROM t2 AS x ...' renames `t2'. It is not a column in
table `t1' because `SELECT column1 FROM t1 ...' is an outer query that
is _farther out_.

For subqueries in `HAVING' or `ORDER BY' clauses, MySQL also looks for
column names in the outer select list.

For certain cases, a correlated subquery is optimized. For example:

     VAL IN (SELECT KEY_VAL FROM TBL_NAME WHERE CORRELATED_CONDITION)

Otherwise, they are inefficient and likely to be slow. Rewriting the
query as a join might improve performance.

Aggregate functions in correlated subqueries may contain outer
references, provided the function contains nothing but outer
references, and provided the function is not contained in another
function or expression.


File: manual.info,  Node: from-clause-subqueries,  Next: subquery-errors,  Prev: correlated-subqueries,  Up: subqueries

13.2.9.8 Subqueries in the `FROM' Clause
........................................

Subqueries are legal in a *Note `SELECT': select.  statement's `FROM'
clause. The actual syntax is:

     SELECT ... FROM (SUBQUERY) [AS] NAME ...

The `[AS] NAME' clause is mandatory, because every table in a `FROM'
clause must have a name. Any columns in the SUBQUERY select list must
have unique names.

For the sake of illustration, assume that you have this table:

     CREATE TABLE t1 (s1 INT, s2 CHAR(5), s3 FLOAT);

Here is how to use a subquery in the `FROM' clause, using the example
table:

     INSERT INTO t1 VALUES (1,'1',1.0);
     INSERT INTO t1 VALUES (2,'2',2.0);
     SELECT sb1,sb2,sb3
       FROM (SELECT s1 AS sb1, s2 AS sb2, s3*2 AS sb3 FROM t1) AS sb
       WHERE sb1 > 1;

Result: `2, '2', 4.0'.

Here is another example: Suppose that you want to know the average of a
set of sums for a grouped table. This does not work:

     SELECT AVG(SUM(column1)) FROM t1 GROUP BY column1;

However, this query provides the desired information:

     SELECT AVG(sum_column1)
       FROM (SELECT SUM(column1) AS sum_column1
             FROM t1 GROUP BY column1) AS t1;

Notice that the column name used within the subquery (`sum_column1') is
recognized in the outer query.

Subqueries in the `FROM' clause can return a scalar, column, row, or
table. Subqueries in the `FROM' clause cannot be correlated subqueries,
unless used within the `ON' clause of a `JOIN' operation.

Subqueries in the `FROM' clause are executed even for the *Note
`EXPLAIN': explain. statement (that is, derived temporary tables are
materialized). This occurs because upper-level queries need information
about all tables during the optimization phase, and the table
represented by a subquery in the `FROM' clause is unavailable unless
the subquery is executed.

It is possible under certain circumstances to modify table data using
*Note `EXPLAIN SELECT': explain. This can occur if the outer query
accesses any tables and an inner query invokes a stored function that
changes one or more rows of a table. Suppose that there are two tables
`t1' and `t2' in database `d1', created as shown here:

     mysql> CREATE DATABASE d1;
     Query OK, 1 row affected (0.00 sec)

     mysql> USE d1;
     Database changed

     mysql> CREATE TABLE t1 (c1 INT);
     Query OK, 0 rows affected (0.15 sec)

     mysql> CREATE TABLE t2 (c1 INT);
     Query OK, 0 rows affected (0.08 sec)

Now we create a stored function `f1' which modifies `t2':

     mysql> DELIMITER //
     mysql> CREATE FUNCTION f1(p1 INT) RETURNS INT
     mysql>   BEGIN
     mysql>     INSERT INTO t2 VALUES (p1);
     mysql>     RETURN p1;
     mysql>   END //
     Query OK, 0 rows affected (0.01 sec)

     mysql> DELIMITER ;

Referencing the function directly in an *Note `EXPLAIN SELECT':
explain. does not have any effect on `t2', as shown here:

     mysql> SELECT * FROM t2;
     Empty set (0.00 sec)

     mysql> EXPLAIN SELECT f1(5);
     +----+-------------+-------+------+---------------+------+---------+------+------+----------------+
     | id | select_type | table | type | possible_keys | key  | key_len | ref  | rows | Extra          |
     +----+-------------+-------+------+---------------+------+---------+------+------+----------------+
     |  1 | SIMPLE      | NULL  | NULL | NULL          | NULL | NULL    | NULL | NULL | No tables used |
     +----+-------------+-------+------+---------------+------+---------+------+------+----------------+
     1 row in set (0.00 sec)

     mysql> SELECT * FROM t2;
     Empty set (0.00 sec)

This is because the *Note `SELECT': select.  statement did not
reference any tables, as can be seen in the `table' and `Extra' columns
of the output. This is also true of the following nested *Note
`SELECT': select.:

     mysql> EXPLAIN SELECT NOW() AS a1, (SELECT f1(5)) AS a2;
     +----+-------------+-------+------+---------------+------+---------+------+------+----------------+
     | id | select_type | table | type | possible_keys | key  | key_len | ref  | rows | Extra          |
     +----+-------------+-------+------+---------------+------+---------+------+------+----------------+
     |  1 | PRIMARY     | NULL  | NULL | NULL          | NULL | NULL    | NULL | NULL | No tables used |
     +----+-------------+-------+------+---------------+------+---------+------+------+----------------+
     1 row in set, 1 warning (0.00 sec)

     mysql> SHOW WARNINGS;
     +-------+------+------------------------------------------+
     | Level | Code | Message                                  |
     +-------+------+------------------------------------------+
     | Note  | 1249 | Select 2 was reduced during optimization |
     +-------+------+------------------------------------------+
     1 row in set (0.00 sec)

     mysql> SELECT * FROM t2;
     Empty set (0.00 sec)

However, if the outer *Note `SELECT': select.  references any tables,
the optimizer executes the statement in the subquery as well:

     mysql> EXPLAIN SELECT * FROM t1 AS a1, (SELECT f1(5)) AS a2;
     +----+-------------+------------+--------+---------------+------+---------+------+------+---------------------+
     | id | select_type | table      | type   | possible_keys | key  | key_len | ref  | rows | Extra               |
     +----+-------------+------------+--------+---------------+------+---------+------+------+---------------------+
     |  1 | PRIMARY     | a1         | system | NULL          | NULL | NULL    | NULL |    0 | const row not found |
     |  1 | PRIMARY     | <derived2> | system | NULL          | NULL | NULL    | NULL |    1 |                     |
     |  2 | DERIVED     | NULL       | NULL   | NULL          | NULL | NULL    | NULL | NULL | No tables used      |
     +----+-------------+------------+--------+---------------+------+---------+------+------+---------------------+
     3 rows in set (0.00 sec)

     mysql> SELECT * FROM t2;
     +------+
     | c1   |
     +------+
     |    5 |
     +------+
     1 row in set (0.00 sec)

This also means that an *Note `EXPLAIN SELECT': explain. statement such
as the one shown here may take a long time to execute because the
`BENCHMARK()' function is executed once for each row in `t1':

     EXPLAIN SELECT * FROM t1 AS a1, (SELECT BENCHMARK(1000000, MD5(NOW())));


File: manual.info,  Node: subquery-errors,  Next: optimizing-subqueries,  Prev: from-clause-subqueries,  Up: subqueries

13.2.9.9 Subquery Errors
........................

There are some errors that apply only to subqueries. This section
describes them.

   * Unsupported subquery syntax:

          ERROR 1235 (ER_NOT_SUPPORTED_YET)
          SQLSTATE = 42000
          Message = "This version of MySQL doesn't yet support
          'LIMIT & IN/ALL/ANY/SOME subquery'"

     This means that MySQL does not support statements of the following
     form:

          SELECT * FROM t1 WHERE s1 IN (SELECT s2 FROM t2 ORDER BY s1 LIMIT 1)

   * Incorrect number of columns from subquery:

          ERROR 1241 (ER_OPERAND_COL)
          SQLSTATE = 21000
          Message = "Operand should contain 1 column(s)"

     This error occurs in cases like this:

          SELECT (SELECT column1, column2 FROM t2) FROM t1;

     You may use a subquery that returns multiple columns, if the
     purpose is row comparison. In other contexts, the subquery must be
     a scalar operand. See *Note row-subqueries::.

   * Incorrect number of rows from subquery:

          ERROR 1242 (ER_SUBSELECT_NO_1_ROW)
          SQLSTATE = 21000
          Message = "Subquery returns more than 1 row"

     This error occurs for statements where the subquery must return at
     most one row but returns multiple rows. Consider the following
     example:

          SELECT * FROM t1 WHERE column1 = (SELECT column1 FROM t2);

     If `SELECT column1 FROM t2' returns just one row, the previous
     query will work. If the subquery returns more than one row, error
     1242 will occur. In that case, the query should be rewritten as:

          SELECT * FROM t1 WHERE column1 = ANY (SELECT column1 FROM t2);

   * Incorrectly used table in subquery:

          Error 1093 (ER_UPDATE_TABLE_USED)
          SQLSTATE = HY000
          Message = "You can't specify target table 'x'
          for update in FROM clause"

     This error occurs in cases such as the following, which attempts
     to modify a table and select from the same table in the subquery:

          UPDATE t1 SET column2 = (SELECT MAX(column1) FROM t1);

     You can use a subquery for assignment within an *Note `UPDATE':
     update. statement because subqueries are legal in *Note `UPDATE':
     update. and *Note `DELETE': delete. statements as well as in *Note
     `SELECT': select. statements.  However, you cannot use the same
     table (in this case, table `t1') for both the subquery `FROM'
     clause and the update target.

For transactional storage engines, the failure of a subquery causes the
entire statement to fail. For nontransactional storage engines, data
modifications made before the error was encountered are preserved.


File: manual.info,  Node: optimizing-subqueries,  Next: rewriting-subqueries,  Prev: subquery-errors,  Up: subqueries

13.2.9.10 Optimizing Subqueries
...............................

Development is ongoing, so no optimization tip is reliable for the long
term. The following list provides some interesting tricks that you
might want to play with:

   * Use subquery clauses that affect the number or order of the rows
     in the subquery. For example:

          SELECT * FROM t1 WHERE t1.column1 IN
            (SELECT column1 FROM t2 ORDER BY column1);
          SELECT * FROM t1 WHERE t1.column1 IN
            (SELECT DISTINCT column1 FROM t2);
          SELECT * FROM t1 WHERE EXISTS
            (SELECT * FROM t2 LIMIT 1);

   * Replace a join with a subquery. For example, try this:

          SELECT DISTINCT column1 FROM t1 WHERE t1.column1 IN (
            SELECT column1 FROM t2);

     Instead of this:

          SELECT DISTINCT t1.column1 FROM t1, t2
            WHERE t1.column1 = t2.column1;

   * Some subqueries can be transformed to joins for compatibility with
     older versions of MySQL that do not support subqueries. However,
     in some cases, converting a subquery to a join may improve
     performance. See *Note rewriting-subqueries::.

   * Move clauses from outside to inside the subquery. For example, use
     this query:

          SELECT * FROM t1
            WHERE s1 IN (SELECT s1 FROM t1 UNION ALL SELECT s1 FROM t2);

     Instead of this query:

          SELECT * FROM t1
            WHERE s1 IN (SELECT s1 FROM t1) OR s1 IN (SELECT s1 FROM t2);

     For another example, use this query:

          SELECT (SELECT column1 + 5 FROM t1) FROM t2;

     Instead of this query:

          SELECT (SELECT column1 FROM t1) + 5 FROM t2;

   * Use a row subquery instead of a correlated subquery. For example,
     use this query:

          SELECT * FROM t1
            WHERE (column1,column2) IN (SELECT column1,column2 FROM t2);

     Instead of this query:

          SELECT * FROM t1
            WHERE EXISTS (SELECT * FROM t2 WHERE t2.column1=t1.column1
                          AND t2.column2=t1.column2);

   * Use `NOT (a = ANY (...))' rather than `a <> ALL (...)'.

   * Use `x = ANY (TABLE CONTAINING (1,2))' rather than `x=1 OR x=2'.

   * Use `= ANY' rather than `EXISTS'.

   * For uncorrelated subqueries that always return one row, `IN' is
     always slower than `='. For example, use this query:

          SELECT * FROM t1
            WHERE t1.COL_NAME = (SELECT a FROM t2 WHERE b = SOME_CONST);

     Instead of this query:

          SELECT * FROM t1
            WHERE t1.COL_NAME IN (SELECT a FROM t2 WHERE b = SOME_CONST);

These tricks might cause programs to go faster or slower. Using MySQL
facilities like the `BENCHMARK()' function, you can get an idea about
what helps in your own situation. See *Note information-functions::.

Some optimizations that MySQL itself makes are:

   * MySQL executes uncorrelated subqueries only once. Use *Note
     `EXPLAIN': explain. to make sure that a given subquery really is
     uncorrelated.

   * MySQL rewrites `IN', `ALL', `ANY', and `SOME' subqueries in an
     attempt to take advantage of the possibility that the select-list
     columns in the subquery are indexed.

   * MySQL replaces subqueries of the following form with an
     index-lookup function, which *Note `EXPLAIN': explain. describes
     as a special join type (`unique_subquery' or `index_subquery'):

          ... IN (SELECT INDEXED_COLUMN FROM SINGLE_TABLE ...)

   * MySQL enhances expressions of the following form with an
     expression involving `MIN()' or `MAX()', unless `NULL' values or
     empty sets are involved:

          VALUE {ALL|ANY|SOME} {> | < | >= | <=} (UNCORRELATED SUBQUERY)

     For example, this `WHERE' clause:

          WHERE 5 > ALL (SELECT x FROM t)

     might be treated by the optimizer like this:

          WHERE 5 > (SELECT MAX(x) FROM t)

See also the MySQL Internals Manual chapter How MySQL Transforms
Subqueries
(http://forge.mysql.com/wiki/MySQL_Internals_Transformations).


File: manual.info,  Node: rewriting-subqueries,  Prev: optimizing-subqueries,  Up: subqueries

13.2.9.11 Rewriting Subqueries as Joins
.......................................

Sometimes there are other ways to test membership in a set of values
than by using a subquery. Also, on some occasions, it is not only
possible to rewrite a query without a subquery, but it can be more
efficient to make use of some of these techniques rather than to use
subqueries. One of these is the `IN()' construct:

For example, this query:

     SELECT * FROM t1 WHERE id IN (SELECT id FROM t2);

Can be rewritten as:

     SELECT DISTINCT t1.* FROM t1, t2 WHERE t1.id=t2.id;

The queries:

     SELECT * FROM t1 WHERE id NOT IN (SELECT id FROM t2);
     SELECT * FROM t1 WHERE NOT EXISTS (SELECT id FROM t2 WHERE t1.id=t2.id);

Can be rewritten as:

     SELECT table1.*
       FROM table1 LEFT JOIN table2 ON table1.id=table2.id
       WHERE table2.id IS NULL;

A `LEFT [OUTER] JOIN' can be faster than an equivalent subquery because
the server might be able to optimize it better--a fact that is not
specific to MySQL Server alone. Prior to SQL-92, outer joins did not
exist, so subqueries were the only way to do certain things. Today,
MySQL Server and many other modern database systems offer a wide range
of outer join types.

MySQL Server supports multiple-table *Note `DELETE': delete. statements
that can be used to efficiently delete rows based on information from
one table or even from many tables at the same time. Multiple-table
*Note `UPDATE': update. statements are also supported. See *Note
delete::, and *Note update::.


File: manual.info,  Node: update,  Prev: subqueries,  Up: sql-syntax-data-manipulation

13.2.10 `UPDATE' Syntax
-----------------------

Single-table syntax:

     UPDATE [LOW_PRIORITY] [IGNORE] TABLE_REFERENCE
         SET COL_NAME1={EXPR1|DEFAULT} [, COL_NAME2={EXPR2|DEFAULT}] ...
         [WHERE WHERE_CONDITION]
         [ORDER BY ...]
         [LIMIT ROW_COUNT]

Multiple-table syntax:

     UPDATE [LOW_PRIORITY] [IGNORE] TABLE_REFERENCES
         SET COL_NAME1={EXPR1|DEFAULT} [, COL_NAME2={EXPR2|DEFAULT}] ...
         [WHERE WHERE_CONDITION]

For the single-table syntax, the *Note `UPDATE': update. statement
updates columns of existing rows in the named table with new values. The
`SET' clause indicates which columns to modify and the values they
should be given. Each value can be given as an expression, or the
keyword `DEFAULT' to set a column explicitly to its default value. The
`WHERE' clause, if given, specifies the conditions that identify which
rows to update. With no `WHERE' clause, all rows are updated. If the
`ORDER BY' clause is specified, the rows are updated in the order that
is specified. The `LIMIT' clause places a limit on the number of rows
that can be updated.

For the multiple-table syntax, *Note `UPDATE': update. updates rows in
each table named in TABLE_REFERENCES that satisfy the conditions. In
this case, `ORDER BY' and `LIMIT' cannot be used.

WHERE_CONDITION is an expression that evaluates to true for each row to
be updated. For expression syntax, see *Note expressions::.

TABLE_REFERENCES and WHERE_CONDITION are is specified as described in
*Note select::.

You need the `UPDATE' privilege only for columns referenced in an *Note
`UPDATE': update.  that are actually updated. You need only the
`SELECT' privilege for any columns that are read but not modified.

The *Note `UPDATE': update. statement supports the following modifiers:

   * With the `LOW_PRIORITY' keyword, execution of the *Note `UPDATE':
     update. is delayed until no other clients are reading from the
     table. This affects only storage engines that use only table-level
     locking (such as `MyISAM', `MEMORY', and `MERGE').

   * With the `IGNORE' keyword, the update statement does not abort
     even if errors occur during the update. Rows for which
     duplicate-key conflicts occur are not updated. Rows for which
     columns are updated to values that would cause data conversion
     errors are updated to the closest valid values instead.

If you access a column from the table to be updated in an expression,
*Note `UPDATE': update. uses the current value of the column. For
example, the following statement sets `col1' to one more than its
current value:

     UPDATE t1 SET col1 = col1 + 1;

The second assignment in the following statement sets `col2' to the
current (updated) `col1' value, not the original `col1' value. The
result is that `col1' and `col2' have the same value. This behavior
differs from standard SQL.

     UPDATE t1 SET col1 = col1 + 1, col2 = col1;

Single-table *Note `UPDATE': update. assignments are generally
evaluated from left to right. For multiple-table updates, there is no
guarantee that assignments are carried out in any particular order.

If you set a column to the value it currently has, MySQL notices this
and does not update it.

If you update a column that has been declared `NOT NULL' by setting to
`NULL', an error occurs if strict SQL mode is enabled; otherwise, the
column is set to the implicit default value for the column data type
and the warning count is incremented. The implicit default value is `0'
for numeric types, the empty string (`''') for string types, and the
`zero' value for date and time types. See *Note data-type-defaults::.

*Note `UPDATE': update. returns the number of rows that were actually
changed. The *Note `mysql_info()': mysql-info. C API function returns
the number of rows that were matched and updated and the number of
warnings that occurred during the *Note `UPDATE': update.

You can use `LIMIT ROW_COUNT' to restrict the scope of the *Note
`UPDATE': update. A `LIMIT' clause is a rows-matched restriction. The
statement stops as soon as it has found ROW_COUNT rows that satisfy the
`WHERE' clause, whether or not they actually were changed.

If an *Note `UPDATE': update. statement includes an `ORDER BY' clause,
the rows are updated in the order specified by the clause. This can be
useful in certain situations that might otherwise result in an error.
Suppose that a table `t' contains a column `id' that has a unique
index. The following statement could fail with a duplicate-key error,
depending on the order in which rows are updated:

     UPDATE t SET id = id + 1;

For example, if the table contains 1 and 2 in the `id' column and 1 is
updated to 2 before 2 is updated to 3, an error occurs. To avoid this
problem, add an `ORDER BY' clause to cause the rows with larger `id'
values to be updated before those with smaller values:

     UPDATE t SET id = id + 1 ORDER BY id DESC;

You can also perform *Note `UPDATE': update.  operations covering
multiple tables. However, you cannot use `ORDER BY' or `LIMIT' with a
multiple-table *Note `UPDATE': update. The TABLE_REFERENCES clause
lists the tables involved in the join. Its syntax is described in *Note
join::. Here is an example:

     UPDATE items,month SET items.price=month.price
     WHERE items.id=month.id;

The preceding example shows an inner join that uses the comma operator,
but multiple-table *Note `UPDATE': update.  statements can use any type
of join permitted in *Note `SELECT': select. statements, such as `LEFT
JOIN'.

If you use a multiple-table *Note `UPDATE': update.  statement
involving `InnoDB' tables for which there are foreign key constraints,
the MySQL optimizer might process tables in an order that differs from
that of their parent/child relationship. In this case, the statement
fails and rolls back. Instead, update a single table and rely on the
`ON UPDATE' capabilities that `InnoDB' provides to cause the other
tables to be modified accordingly. See *Note
innodb-foreign-key-constraints::.

Currently, you cannot update a table and select from the same table in
a subquery.

Index hints (see *Note index-hints::) are accepted but ignored for
*Note `UPDATE': update. statements.


File: manual.info,  Node: sql-syntax-transactions,  Next: sql-syntax-replication,  Prev: sql-syntax-data-manipulation,  Up: sql-syntax

13.3 MySQL Transactional and Locking Statements
===============================================

* Menu:

* commit::                       `START TRANSACTION', `COMMIT', and `ROLLBACK' Syntax
* cannot-roll-back::             Statements That Cannot Be Rolled Back
* implicit-commit::              Statements That Cause an Implicit Commit
* savepoint::                    `SAVEPOINT' and `ROLLBACK TO SAVEPOINT' Syntax
* lock-tables::                  `LOCK TABLES' and `UNLOCK TABLES' Syntax
* set-transaction::              `SET TRANSACTION' Syntax
* xa::                           XA Transactions

MySQL supports local transactions (within a given client session)
through statements such as *Note `SET autocommit': commit, *Note `START
TRANSACTION': commit, *Note `COMMIT': commit, and *Note `ROLLBACK':
commit. See *Note commit::. Beginning with MySQL 5.0, XA transaction
support is available, which enables MySQL to participate in distributed
transactions as well. See *Note xa::.


File: manual.info,  Node: commit,  Next: cannot-roll-back,  Prev: sql-syntax-transactions,  Up: sql-syntax-transactions

13.3.1 `START TRANSACTION', `COMMIT', and `ROLLBACK' Syntax
-----------------------------------------------------------

     START TRANSACTION [WITH CONSISTENT SNAPSHOT] | BEGIN [WORK]
     COMMIT [WORK] [AND [NO] CHAIN] [[NO] RELEASE]
     ROLLBACK [WORK] [AND [NO] CHAIN] [[NO] RELEASE]
     SET autocommit = {0 | 1}

The *Note `START TRANSACTION': commit. or *Note `BEGIN': commit.
statement begins a new transaction. *Note `COMMIT': commit.  commits
the current transaction, making its changes permanent.  *Note
`ROLLBACK': commit. rolls back the current transaction, canceling its
changes. The *Note `SET autocommit': commit.  statement disables or
enables the default autocommit mode for the current session.

Beginning with MySQL 5.0.3, the optional `WORK' keyword is supported
for *Note `COMMIT': commit. and *Note `ROLLBACK': commit, as are the
`CHAIN' and `RELEASE' clauses. `CHAIN' and `RELEASE' can be used for
additional control over transaction completion.  The value of the
`completion_type' system variable determines the default completion
behavior. See *Note server-system-variables::.

*Note*:

Within stored programs (stored procedures and functions, and triggers),
the parser treats *Note `BEGIN [WORK]': commit.  as the beginning of a
*Note `BEGIN ... END': begin-end. block. Begin a transaction in this
context with *Note `START TRANSACTION': commit. instead.

The `AND CHAIN' clause causes a new transaction to begin as soon as the
current one ends, and the new transaction has the same isolation level
as the just-terminated transaction.  The `RELEASE' clause causes the
server to disconnect the current client session after terminating the
current transaction. Including the `NO' keyword suppresses `CHAIN' or
`RELEASE' completion, which can be useful if the `completion_type'
system variable is set to cause chaining or release completion by
default.

By default, MySQL runs with autocommit mode enabled. This means that as
soon as you execute a statement that updates (modifies) a table, MySQL
stores the update on disk to make it permanent. To disable autocommit
mode, use the following statement:

     SET autocommit=0;

After disabling autocommit mode by setting the `autocommit' variable to
zero, changes to transaction-safe tables (such as those for `InnoDB',
`BDB', or *Note `NDBCLUSTER': mysql-cluster.) are not made permanent
immediately. You must use *Note `COMMIT': commit. to store your changes
to disk or *Note `ROLLBACK': commit. to ignore the changes.

`autocommit' is a session variable and must be set for each session. If
you want to disable autocommit mode for each new connection, see the
description of the `autocommit' system variable at *Note
server-system-variables::.

To disable autocommit mode for a single series of statements, use the
*Note `START TRANSACTION': commit. statement:

     START TRANSACTION;
     SELECT @A:=SUM(salary) FROM table1 WHERE type=1;
     UPDATE table2 SET summary=@A WHERE type=1;
     COMMIT;

With *Note `START TRANSACTION': commit, autocommit remains disabled
until you end the transaction with *Note `COMMIT': commit. or *Note
`ROLLBACK': commit. The autocommit mode then reverts to its previous
state.

*Note `BEGIN': commit. and *Note `BEGIN WORK': commit. are supported as
aliases of *Note `START TRANSACTION': commit. for initiating a
transaction.  *Note `START TRANSACTION': commit. is standard SQL syntax
and is the recommended way to start an ad-hoc transaction.

*Important*:

Many APIs used for writing MySQL client applications (such as JDBC)
provide their own methods for starting transactions that can (and
sometimes should) be used instead of sending a *Note `START
TRANSACTION': commit. statement from the client. See *Note
connectors-apis::, or the documentation for your API, for more
information.

The *Note `BEGIN': commit.  statement differs from the use of the
`BEGIN' keyword that starts a *Note `BEGIN ... END': begin-end.
compound statement. The latter does not begin a transaction. See *Note
begin-end::.

You can also begin a transaction like this:

     START TRANSACTION WITH CONSISTENT SNAPSHOT;

The `WITH CONSISTENT SNAPSHOT' clause starts a consistent read for
storage engines that are capable of it. This applies only to `InnoDB'.
The effect is the same as issuing a *Note `START TRANSACTION': commit.
followed by a *Note `SELECT': select. from any `InnoDB' table. See
*Note innodb-consistent-read::. The `WITH CONSISTENT SNAPSHOT' clause
does not change the current transaction isolation level, so it provides
a consistent snapshot only if the current isolation level is one that
permits consistent read (`REPEATABLE READ' or `SERIALIZABLE').

Beginning a transaction causes any pending transaction to be committed.
See *Note implicit-commit::, for more information.

Beginning a transaction also causes table locks acquired with *Note
`LOCK TABLES': lock-tables. to be released, as though you had executed
*Note `UNLOCK TABLES': lock-tables. Beginning a transaction does not
release a global read lock acquired with *Note `FLUSH TABLES WITH READ
LOCK': flush.

For best results, transactions should be performed using only tables
managed by a single transaction-safe storage engine.  Otherwise, the
following problems can occur:

   * If you use tables from more than one transaction-safe storage
     engine (such as `InnoDB' and `BDB'), and the transaction isolation
     level is not `SERIALIZABLE', it is possible that when one
     transaction commits, another ongoing transaction that uses the
     same tables will see only some of the changes made by the first
     transaction. That is, the atomicity of transactions is not
     guaranteed with mixed engines and inconsistencies can result. (If
     mixed-engine transactions are infrequent, you can use *Note `SET
     TRANSACTION ISOLATION LEVEL': set-transaction. to set the isolation
     level to `SERIALIZABLE' on a per-transaction basis as necessary.)

   * If you use tables that are not transaction-safe within a
     transaction, changes to those tables are stored at once,
     regardless of the status of autocommit mode.

   * If you issue a *Note `ROLLBACK': commit.  statement after updating
     a nontransactional table within a transaction, an
     `ER_WARNING_NOT_COMPLETE_ROLLBACK' warning occurs. Changes to
     transaction-safe tables are rolled back, but not changes to
     nontransaction-safe tables.

Each transaction is stored in the binary log in one chunk, upon *Note
`COMMIT': commit. Transactions that are rolled back are not logged.
(*Exception*: Modifications to nontransactional tables cannot be rolled
back. If a transaction that is rolled back includes modifications to
nontransactional tables, the entire transaction is logged with a *Note
`ROLLBACK': commit.  statement at the end to ensure that modifications
to the nontransactional tables are replicated.) See *Note binary-log::.

You can change the isolation level for transactions with *Note `SET
TRANSACTION ISOLATION LEVEL': set-transaction. See *Note
set-transaction::.

Rolling back can be a slow operation that may occur implicitly without
the user having explicitly asked for it (for example, when an error
occurs). Because of this, *Note `SHOW PROCESSLIST': show-processlist.
displays `Rolling back' in the `State' column for the session, not only
for explicit rollbacks performed with the *Note `ROLLBACK': commit.
statement but also for implicit rollbacks.

*Note*:

Beginning with MySQL 5.0.84, `BEGIN', `COMMIT', and `ROLLBACK' are no
longer affected by `--replicate-do-db' or `--replicate-ignore-db'
rules. (Bug #43263)


File: manual.info,  Node: cannot-roll-back,  Next: implicit-commit,  Prev: commit,  Up: sql-syntax-transactions

13.3.2 Statements That Cannot Be Rolled Back
--------------------------------------------

Some statements cannot be rolled back. In general, these include data
definition language (DDL) statements, such as those that create or drop
databases, those that create, drop, or alter tables or stored routines.

You should design your transactions not to include such statements. If
you issue a statement early in a transaction that cannot be rolled
back, and then another statement later fails, the full effect of the
transaction cannot be rolled back in such cases by issuing a *Note
`ROLLBACK': commit.  statement.


File: manual.info,  Node: implicit-commit,  Next: savepoint,  Prev: cannot-roll-back,  Up: sql-syntax-transactions

13.3.3 Statements That Cause an Implicit Commit
-----------------------------------------------

The statements listed in this section (and any synonyms for them)
implicitly end a transaction, as if you had done a *Note `COMMIT':
commit. before executing the statement.

   * *Data definition language (DDL) statements that define or modify
     database objects.* *Note `ALTER TABLE': alter-table, *Note `CREATE
     INDEX': create-index, *Note `DROP INDEX': drop-index, *Note `DROP
     TABLE': drop-table, *Note `RENAME TABLE': rename-table.

     *Note `ALTER TABLE': alter-table, *Note `CREATE TABLE':
     create-table, and *Note `DROP TABLE': drop-table. do not commit a
     transaction if the `TEMPORARY' keyword is used. (This does not
     apply to other operations on temporary tables such as *Note
     `CREATE INDEX': create-index, which do cause a commit.) However,
     although no implicit commit occurs, neither can the statement be
     rolled back. Therefore, use of such statements will violate
     transaction atomicity: For example, if you use *Note `CREATE
     TEMPORARY TABLE': create-table. and then roll back the
     transaction, the table remains in existence.

     The *Note `CREATE TABLE': create-table. statement in `InnoDB' is
     processed as a single transaction. This means that a *Note
     `ROLLBACK': commit.  from the user does not undo *Note `CREATE
     TABLE': create-table. statements the user made during that
     transaction.

     Beginning with MySQL 5.0.8, *Note `CREATE TABLE': create-table,
     *Note `CREATE DATABASE': create-database. *Note `DROP DATABASE':
     drop-database, and *Note `TRUNCATE TABLE': truncate-table. cause
     an implicit commit.

     Beginning with MySQL 5.0.13, *Note `ALTER PROCEDURE':
     alter-procedure, *Note `CREATE PROCEDURE': create-procedure, and
     *Note `DROP PROCEDURE': drop-procedure. cause an implicit commit.

     Also beginning with MySQL 5.0.13, *Note `ALTER FUNCTION':
     alter-function, *Note `CREATE FUNCTION': create-function. and
     *Note `DROP FUNCTION': drop-function. cause an implicit commit
     when used with stored functions, but not with UDFs.  (*Note `ALTER
     FUNCTION': alter-function. can only be used with stored functions.)

     Beginning with MySQL 5.0.15, *Note `ALTER VIEW': alter-view, *Note
     `CREATE TRIGGER': create-trigger, *Note `CREATE VIEW': create-view,
     *Note `DROP TRIGGER': drop-trigger, and *Note `DROP VIEW':
     drop-view. cause an implicit commit.

   * *Statements that implicitly use or modify tables in the `mysql'
     database.* Beginning with MySQL 5.0.15, *Note `CREATE USER':
     create-user, *Note `DROP USER': drop-user, and *Note `RENAME
     USER': rename-user. cause an implicit commit.

   * *Transaction-control and locking statements.* *Note `BEGIN':
     commit, *Note `LOCK TABLES': lock-tables, `SET autocommit = 1' (if
     the value is not already 1), *Note `START TRANSACTION': commit,
     *Note `UNLOCK TABLES': lock-tables.

     *Note `UNLOCK TABLES': lock-tables. commits a transaction only if
     any tables currently have been locked with *Note `LOCK TABLES':
     lock-tables. This does not occur for *Note `UNLOCK TABLES':
     lock-tables. following *Note `FLUSH TABLES WITH READ LOCK': flush.
     because the latter statement does not acquire table-level locks.

     Transactions cannot be nested. This is a consequence of the
     implicit commit performed for any current transaction when you
     issue a *Note `START TRANSACTION': commit. statement or one of its
     synonyms.

     Statements that cause an implicit commit cannot be used in an XA
     transaction while the transaction is in an `ACTIVE' state.

     The *Note `BEGIN': commit.  statement differs from the use of the
     `BEGIN' keyword that starts a *Note `BEGIN ... END': begin-end.
     compound statement. The latter does not cause an implicit commit.
     See *Note begin-end::.

   * *Data loading statements.* `LOAD MASTER DATA', *Note `LOAD DATA
     INFILE': load-data. Before MySQL 5.0.26, *Note `LOAD DATA INFILE':
     load-data. caused an implicit commit for all storage engines. As
     of MySQL 5.0.26, it causes an implicit commit only for tables
     using the *Note `NDB': mysql-cluster. storage engine. For more
     information, see Bug #11151.


File: manual.info,  Node: savepoint,  Next: lock-tables,  Prev: implicit-commit,  Up: sql-syntax-transactions

13.3.4 `SAVEPOINT' and `ROLLBACK TO SAVEPOINT' Syntax
-----------------------------------------------------

     SAVEPOINT IDENTIFIER
     ROLLBACK [WORK] TO [SAVEPOINT] IDENTIFIER
     RELEASE SAVEPOINT IDENTIFIER

`InnoDB' supports the SQL statements *Note `SAVEPOINT': savepoint. and
*Note `ROLLBACK TO SAVEPOINT': commit. Starting from MySQL 5.0.3, *Note
`RELEASE SAVEPOINT': commit. and the optional `WORK' keyword for *Note
`ROLLBACK': commit. are supported as well.

The *Note `SAVEPOINT': savepoint. statement sets a named transaction
savepoint with a name of IDENTIFIER. If the current transaction has a
savepoint with the same name, the old savepoint is deleted and a new
one is set.

The *Note `ROLLBACK TO SAVEPOINT': commit. statement rolls back a
transaction to the named savepoint without terminating the transaction.
(The *Note `SAVEPOINT': savepoint. keyword is optional as of MySQL
5.0.3.) Modifications that the current transaction made to rows after
the savepoint was set are undone in the rollback, but `InnoDB' does
_not_ release the row locks that were stored in memory after the
savepoint. (For a new inserted row, the lock information is carried by
the transaction ID stored in the row; the lock is not separately stored
in memory. In this case, the row lock is released in the undo.)
Savepoints that were set at a later time than the named savepoint are
deleted.

If the *Note `ROLLBACK TO SAVEPOINT': commit. statement returns the
following error, it means that no savepoint with the specified name
exists:

     ERROR 1305 (42000): SAVEPOINT IDENTIFIER does not exist

The *Note `RELEASE SAVEPOINT': commit. statement removes the named
savepoint from the set of savepoints of the current transaction. No
commit or rollback occurs. It is an error if the savepoint does not
exist.

All savepoints of the current transaction are deleted if you execute a
*Note `COMMIT': commit, or a *Note `ROLLBACK': commit. that does not
name a savepoint.

Beginning with MySQL 5.0.17, a new savepoint level is created when a
stored function is invoked or a trigger is activated. The savepoints on
previous levels become unavailable and thus do not conflict with
savepoints on the new level. When the function or trigger terminates,
any savepoints it created are released and the previous savepoint level
is restored.


File: manual.info,  Node: lock-tables,  Next: set-transaction,  Prev: savepoint,  Up: sql-syntax-transactions

13.3.5 `LOCK TABLES' and `UNLOCK TABLES' Syntax
-----------------------------------------------

* Menu:

* lock-tables-and-transactions::  Interaction of Table Locking and Transactions
* lock-tables-and-triggers::     `LOCK TABLES' and Triggers
* lock-tables-restrictions::     Table-Locking Restrictions and Conditions

     LOCK TABLES
         TBL_NAME [[AS] ALIAS] LOCK_TYPE
         [, TBL_NAME [[AS] ALIAS] LOCK_TYPE] ...

     LOCK_TYPE:
         READ [LOCAL]
       | [LOW_PRIORITY] WRITE

     UNLOCK TABLES

MySQL enables client sessions to acquire table locks explicitly for the
purpose of cooperating with other sessions for access to tables, or to
prevent other sessions from modifying tables during periods when a
session requires exclusive access to them. A session can acquire or
release locks only for itself. One session cannot acquire locks for
another session or release locks held by another session.

Locks may be used to emulate transactions or to get more speed when
updating tables. This is explained in more detail later in this section.

*Note `LOCK TABLES': lock-tables. explicitly acquires table locks for
the current client session. Table locks can be acquired for base tables
or (as of MySQL 5.0.6) views. You must have the `LOCK TABLES'
privilege, and the `SELECT' privilege for each object to be locked.

For view locking, *Note `LOCK TABLES': lock-tables. adds all base
tables used in the view to the set of tables to be locked and locks
them automatically. If you lock a table explicitly with *Note `LOCK
TABLES': lock-tables, any tables used in triggers are also locked
implicitly, as described in *Note lock-tables-and-triggers::.

*Note `UNLOCK TABLES': lock-tables. explicitly releases any table locks
held by the current session.

Another use for *Note `UNLOCK TABLES': lock-tables. is to release the
global read lock acquired with the *Note `FLUSH TABLES WITH READ LOCK':
flush. statement, which enables you to lock all tables in all
databases. See *Note flush::. (This is a very convenient way to get
backups if you have a file system such as Veritas that can take
snapshots in time.)

A table lock protects only against inappropriate reads or writes by
other sessions. The session holding the lock, even a read lock, can
perform table-level operations such as *Note `DROP TABLE': drop-table.
Truncate operations are not transaction-safe, so an error occurs if the
session attempts one during an active transaction or while holding a
table lock.

The following discussion applies only to non-`TEMPORARY' tables. *Note
`LOCK TABLES': lock-tables. is permitted (but ignored) for a
`TEMPORARY' table. The table can be accessed freely by the session
within which it was created, regardless of what other locking may be in
effect. No lock is necessary because no other session can see the table.

For information about other conditions on the use of *Note `LOCK
TABLES': lock-tables. and statements that cannot be used while *Note
`LOCK TABLES': lock-tables. is in effect, see *Note
lock-tables-restrictions::

*Rules for Lock Acquisition*

To acquire table locks within the current session, use the *Note `LOCK
TABLES': lock-tables. statement. The following lock types are available:

`READ [LOCAL]' lock:

   * The session that holds the lock can read the table (but not write
     it).

   * Multiple sessions can acquire a `READ' lock for the table at the
     same time.

   * Other sessions can read the table without explicitly acquiring a
     `READ' lock.

   * The `LOCAL' modifier enables nonconflicting *Note `INSERT':
     insert. statements (concurrent inserts) by other sessions to
     execute while the lock is held.  (See *Note concurrent-inserts::.)
     However, `READ LOCAL' cannot be used if you are going to
     manipulate the database using processes external to the server
     while you hold the lock. For `InnoDB' tables, `READ LOCAL' is the
     same as `READ' as of MySQL 5.0.13. (Before that, `READ LOCAL'
     essentially does nothing: It does not lock the table at all, so for
     `InnoDB' tables, the use of `READ LOCAL' is deprecated because a
     plain consistent-read *Note `SELECT': select. does the same thing,
     and no locks are needed.)

`[LOW_PRIORITY] WRITE' lock:

   * The session that holds the lock can read and write the table.

   * Only the session that holds the lock can access the table. No
     other session can access it until the lock is released.

   * Lock requests for the table by other sessions block while the
     `WRITE' lock is held.

   * The `LOW_PRIORITY' modifier affects lock scheduling if the `WRITE'
     lock request must wait, as described later.

If the *Note `LOCK TABLES': lock-tables. statement must wait due to
locks held by other sessions on any of the tables, it blocks until all
locks can be acquired.

A session that requires locks must acquire all the locks that it needs
in a single *Note `LOCK TABLES': lock-tables.  statement. While the
locks thus obtained are held, the session can access only the locked
tables. For example, in the following sequence of statements, an error
occurs for the attempt to access `t2' because it was not locked in the
*Note `LOCK TABLES': lock-tables. statement:

     mysql> LOCK TABLES t1 READ;
     mysql> SELECT COUNT(*) FROM t1;
     +----------+
     | COUNT(*) |
     +----------+
     |        3 |
     +----------+
     mysql> SELECT COUNT(*) FROM t2;
     ERROR 1100 (HY000): Table 't2' was not locked with LOCK TABLES

Tables in the `INFORMATION_SCHEMA' database are an exception. They can
be accessed without being locked explicitly even while a session holds
table locks obtained with *Note `LOCK TABLES': lock-tables.

You cannot refer to a locked table multiple times in a single query
using the same name. Use aliases instead, and obtain a separate lock
for the table and each alias:

     mysql> LOCK TABLE t WRITE, t AS t1 READ;
     mysql> INSERT INTO t SELECT * FROM t;
     ERROR 1100: Table 't' was not locked with LOCK TABLES
     mysql> INSERT INTO t SELECT * FROM t AS t1;

The error occurs for the first *Note `INSERT': insert. because there
are two references to the same name for a locked table. The second
*Note `INSERT': insert. succeeds because the references to the table
use different names.

If your statements refer to a table by means of an alias, you must lock
the table using that same alias. It does not work to lock the table
without specifying the alias:

     mysql> LOCK TABLE t READ;
     mysql> SELECT * FROM t AS myalias;
     ERROR 1100: Table 'myalias' was not locked with LOCK TABLES

Conversely, if you lock a table using an alias, you must refer to it in
your statements using that alias:

     mysql> LOCK TABLE t AS myalias READ;
     mysql> SELECT * FROM t;
     ERROR 1100: Table 't' was not locked with LOCK TABLES
     mysql> SELECT * FROM t AS myalias;

`WRITE' locks normally have higher priority than `READ' locks to ensure
that updates are processed as soon as possible. This means that if one
session obtains a `READ' lock and then another session requests a
`WRITE' lock, subsequent `READ' lock requests wait until the session
that requested the `WRITE' lock has obtained the lock and released it.
A request for a `LOW_PRIORITY WRITE' lock, by contrast, permits
subsequent `READ' lock requests by other sessions to be satisfied first
if they occur while the `LOW_PRIORITY WRITE' request is waiting. You
should use `LOW_PRIORITY WRITE' locks only if you are sure that
eventually there will be a time when no sessions have a `READ' lock.
For `InnoDB' tables in transactional mode (autocommit = 0), a waiting
`LOW_PRIORITY WRITE' lock acts like a regular `WRITE' lock and causes
subsequent `READ' lock requests to wait.

*Note `LOCK TABLES': lock-tables. acquires locks as follows:

  1. Sort all tables to be locked in an internally defined order.  From
     the user standpoint, this order is undefined.

  2. If a table is to be locked with a read and a write lock, put the
     write lock request before the read lock request.

  3. Lock one table at a time until the session gets all locks.

This policy ensures that table locking is deadlock free. There are,
however, other things you need to be aware of about this policy: If you
are using a `LOW_PRIORITY WRITE' lock for a table, it means only that
MySQL waits for this particular lock until there are no other sessions
that want a `READ' lock. When the session has gotten the `WRITE' lock
and is waiting to get the lock for the next table in the lock table
list, all other sessions wait for the `WRITE' lock to be released. If
this becomes a serious problem with your application, you should
consider converting some of your tables to transaction-safe tables.

*Rules for Lock Release*

When the table locks held by a session are released, they are all
released at the same time. A session can release its locks explicitly,
or locks may be released implicitly under certain conditions.

   * A session can release its locks explicitly with *Note `UNLOCK
     TABLES': lock-tables.

   * If a session issues a *Note `LOCK TABLES': lock-tables. statement
     to acquire a lock while already holding locks, its existing locks
     are released implicitly before the new locks are granted.

   * If a session begins a transaction (for example, with *Note `START
     TRANSACTION': commit.), an implicit *Note `UNLOCK TABLES':
     lock-tables. is performed, which causes existing locks to be
     released. (For additional information about the interaction
     between table locking and transactions, see *Note
     lock-tables-and-transactions::.)

If the connection for a client session terminates, whether normally or
abnormally, the server implicitly releases all table locks held by the
session (transactional and nontransactional). If the client reconnects,
the locks will no longer be in effect. In addition, if the client had
an active transaction, the server rolls back the transaction upon
disconnect, and if reconnect occurs, the new session begins with
autocommit enabled. For this reason, clients may wish to disable
auto-reconnect. With auto-reconnect in effect, the client is not
notified if reconnect occurs but any table locks or current transaction
will have been lost. With auto-reconnect disabled, if the connection
drops, an error occurs for the next statement issued. The client can
detect the error and take appropriate action such as reacquiring the
locks or redoing the transaction. See *Note auto-reconnect::.

*Note*:

If you use *Note `ALTER TABLE': alter-table. on a locked table, it may
become unlocked. For example, if you attempt a second *Note `ALTER
TABLE': alter-table.  operation, the result may be an error `Table
'TBL_NAME' was not locked with LOCK TABLES'. To handle this, lock the
table again prior to the second alteration. See also *Note
alter-table-problems::.


File: manual.info,  Node: lock-tables-and-transactions,  Next: lock-tables-and-triggers,  Prev: lock-tables,  Up: lock-tables

13.3.5.1 Interaction of Table Locking and Transactions
......................................................

*Note `LOCK TABLES': lock-tables. and *Note `UNLOCK TABLES':
lock-tables. interact with the use of transactions as follows:

   * *Note `LOCK TABLES': lock-tables. is not transaction-safe and
     implicitly commits any active transaction before attempting to
     lock the tables.

   * *Note `UNLOCK TABLES': lock-tables. implicitly commits any active
     transaction, but only if *Note `LOCK TABLES': lock-tables. has
     been used to acquire table locks. For example, in the following
     set of statements, *Note `UNLOCK TABLES': lock-tables. releases
     the global read lock but does not commit the transaction because
     no table locks are in effect:

          FLUSH TABLES WITH READ LOCK;
          START TRANSACTION;
          SELECT ... ;
          UNLOCK TABLES;

   * Beginning a transaction (for example, with *Note `START
     TRANSACTION': commit.) implicitly commits any current transaction
     and releases existing locks.

   * Other statements that implicitly cause transactions to be
     committed do not release existing locks. For a list of such
     statements, see *Note implicit-commit::.

   * The correct way to use *Note `LOCK TABLES': lock-tables. and *Note
     `UNLOCK TABLES': lock-tables. with transactional tables, such as
     `InnoDB' tables, is to begin a transaction with `SET autocommit =
     0' (not *Note `START TRANSACTION': commit.) followed by *Note
     `LOCK TABLES': lock-tables, and to not call *Note `UNLOCK TABLES':
     lock-tables. until you commit the transaction explicitly. For
     example, if you need to write to table `t1' and read from table
     `t2', you can do this:

          SET autocommit=0;
          LOCK TABLES t1 WRITE, t2 READ, ...;... DO SOMETHING WITH TABLES T1 AND T2 HERE ...
          COMMIT;
          UNLOCK TABLES;

     When you call *Note `LOCK TABLES': lock-tables, `InnoDB'
     internally takes its own table lock, and MySQL takes its own table
     lock.  `InnoDB' releases its internal table lock at the next
     commit, but for MySQL to release its table lock, you have to call
     *Note `UNLOCK TABLES': lock-tables. You should not have
     `autocommit = 1', because then `InnoDB' releases its internal table
     lock immediately after the call of *Note `LOCK TABLES':
     lock-tables, and deadlocks can very easily happen.  `InnoDB' does
     not acquire the internal table lock at all if `autocommit = 1', to
     help old applications avoid unnecessary deadlocks.

   * *Note `ROLLBACK': commit.  does not release table locks.

   * *Note `FLUSH TABLES WITH READ LOCK': flush. acquires a global read
     lock and not table locks, so it is not subject to the same
     behavior as *Note `LOCK TABLES': lock-tables. and *Note `UNLOCK
     TABLES': lock-tables. with respect to table locking and implicit
     commits. See *Note flush::.


File: manual.info,  Node: lock-tables-and-triggers,  Next: lock-tables-restrictions,  Prev: lock-tables-and-transactions,  Up: lock-tables

13.3.5.2 `LOCK TABLES' and Triggers
...................................

If you lock a table explicitly with *Note `LOCK TABLES': lock-tables,
any tables used in triggers are also locked implicitly:

   * The locks are taken as the same time as those acquired explicitly
     with the *Note `LOCK TABLES': lock-tables. statement.

   * The lock on a table used in a trigger depends on whether the table
     is used only for reading. If so, a read lock suffices.  Otherwise,
     a write lock is used.

   * If a table is locked explicitly for reading with *Note `LOCK
     TABLES': lock-tables, but needs to be locked for writing because
     it might be modified within a trigger, a write lock is taken
     rather than a read lock.  (That is, an implicit write lock needed
     due to the table's appearance within a trigger causes an explicit
     read lock request for the table to be converted to a write lock
     request.)

Suppose that you lock two tables, `t1' and `t2', using this statement:

     LOCK TABLES t1 WRITE, t2 READ;

If `t1' or `t2' have any triggers, tables used within the triggers will
also be locked.  Suppose that `t1' has a trigger defined like this:

     CREATE TRIGGER t1_a_ins AFTER INSERT ON t1 FOR EACH ROW
     BEGIN
       UPDATE t4 SET count = count+1
           WHERE id = NEW.id AND EXISTS (SELECT a FROM t3);
       INSERT INTO t2 VALUES(1, 2);
     END;

The result of the *Note `LOCK TABLES': lock-tables.  statement is that
`t1' and `t2' are locked because they appear in the statement, and `t3'
and `t4' are locked because they are used within the trigger:

   * `t1' is locked for writing per the `WRITE' lock request.

   * `t2' is locked for writing, even though the request is for a
     `READ' lock. This occurs because `t2' is inserted into within the
     trigger, so the `READ' request is converted to a `WRITE' request.

   * `t3' is locked for reading because it is only read from within the
     trigger.

   * `t4' is locked for writing because it might be updated within the
     trigger.


File: manual.info,  Node: lock-tables-restrictions,  Prev: lock-tables-and-triggers,  Up: lock-tables

13.3.5.3 Table-Locking Restrictions and Conditions
..................................................

You can safely use *Note `KILL': kill. to terminate a session that is
waiting for a table lock. See *Note kill::.

You should _not_ lock any tables that you are using with *Note `INSERT
DELAYED': insert-delayed. An *Note `INSERT DELAYED': insert-delayed. in
this case results in an error because the insert must be handled by a
separate thread, not by the session which holds the lock.

*Note `LOCK TABLES': lock-tables. and *Note `UNLOCK TABLES':
lock-tables. cannot be used within stored programs.

Normally, you do not need to lock tables, because all single *Note
`UPDATE': update. statements are atomic; no other session can interfere
with any other currently executing SQL statement. However, there are a
few cases when locking tables may provide an advantage:

   * If you are going to run many operations on a set of `MyISAM'
     tables, it is much faster to lock the tables you are going to use.
     Locking `MyISAM' tables speeds up inserting, updating, or deleting
     on them because MySQL does not flush the key cache for the locked
     tables until *Note `UNLOCK TABLES': lock-tables. is called.
     Normally, the key cache is flushed after each SQL statement.

     The downside to locking the tables is that no session can update a
     `READ'-locked table (including the one holding the lock) and no
     session can access a `WRITE'-locked table other than the one
     holding the lock.

   * If you are using tables for a nontransactional storage engine, you
     must use *Note `LOCK TABLES': lock-tables. if you want to ensure
     that no other session modifies the tables between a *Note
     `SELECT': select. and an *Note `UPDATE': update. The example shown
     here requires *Note `LOCK TABLES': lock-tables. to execute safely:

          LOCK TABLES trans READ, customer WRITE;
          SELECT SUM(value) FROM trans WHERE customer_id=SOME_ID;
          UPDATE customer
            SET total_value=SUM_FROM_PREVIOUS_STATEMENT
            WHERE customer_id=SOME_ID;
          UNLOCK TABLES;

     Without *Note `LOCK TABLES': lock-tables, it is possible that
     another session might insert a new row in the `trans' table
     between execution of the *Note `SELECT': select. and *Note
     `UPDATE': update. statements.

You can avoid using *Note `LOCK TABLES': lock-tables.  in many cases by
using relative updates (`UPDATE customer SET VALUE=VALUE+NEW_VALUE') or
the `LAST_INSERT_ID()' function.  See *Note ansi-diff-transactions::.

You can also avoid locking tables in some cases by using the user-level
advisory lock functions `GET_LOCK()' and `RELEASE_LOCK()'. These locks
are saved in a hash table in the server and implemented with
`pthread_mutex_lock()' and `pthread_mutex_unlock()' for high speed. See
*Note miscellaneous-functions::.

See *Note internal-locking::, for more information on locking policy.


File: manual.info,  Node: set-transaction,  Next: xa,  Prev: lock-tables,  Up: sql-syntax-transactions

13.3.6 `SET TRANSACTION' Syntax
-------------------------------

     SET [GLOBAL | SESSION] TRANSACTION ISOLATION LEVEL
       {
            READ UNCOMMITTED
          | READ COMMITTED
          | REPEATABLE READ
          | SERIALIZABLE
        }

This statement sets the transaction isolation level globally, for the
current session, or for the next transaction:

   * With the `GLOBAL' keyword, the statement sets the default
     transaction level globally for all subsequent sessions. Existing
     sessions are unaffected.

   * With the `SESSION' keyword, the statement sets the default
     transaction level for all subsequent transactions performed within
     the current session.

   * Without any `SESSION' or `GLOBAL' keyword, the statement sets the
     isolation level for the next (not started) transaction performed
     within the current session.

A change to the global default isolation level requires the `SUPER'
privilege. Any session is free to change its session isolation level
(even in the middle of a transaction), or the isolation level for its
next transaction.

To set the global default isolation level at server startup, use the
`--transaction-isolation=LEVEL' option to *Note `mysqld': mysqld. on
the command line or in an option file. Values of LEVEL for this option
use dashes rather than spaces, so the permissible values are
`READ-UNCOMMITTED', `READ-COMMITTED', `REPEATABLE-READ', or
`SERIALIZABLE'. For example, to set the default isolation level to
`REPEATABLE READ', use these lines in the `[mysqld]' section of an
option file:

     [mysqld]
     transaction-isolation = REPEATABLE-READ

To determine the global and session transaction isolation levels at
runtime, check the value of the `tx_isolation' system variable:

     SELECT @@GLOBAL.tx_isolation, @@tx_isolation;

`InnoDB' supports each of the transaction isolation levels described
here using different locking strategies. The default level is
`REPEATABLE READ'. For additional information about `InnoDB'
record-level locks and how it uses them to execute various types of
statements, see *Note innodb-record-level-locks::, and *Note
innodb-locks-set::.

The following list describes how MySQL supports the different
transaction levels:

   *  `READ UNCOMMITTED'

     *Note `SELECT': select. statements are performed in a nonlocking
     fashion, but a possible earlier version of a row might be used.
     Thus, using this isolation level, such reads are not consistent.
     This is also called a `dirty read.' Otherwise, this isolation
     level works like `READ COMMITTED'.

   *  `READ COMMITTED'

     A somewhat Oracle-like isolation level with respect to consistent
     (nonlocking) reads: Each consistent read, even within the same
     transaction, sets and reads its own fresh snapshot. See *Note
     innodb-consistent-read::.

     For locking reads (*Note `SELECT': select. with `FOR UPDATE' or
     `LOCK IN SHARE MODE'), `InnoDB' locks only index records, not the
     gaps before them, and thus permits the free insertion of new
     records next to locked records. For *Note `UPDATE': update. and
     *Note `DELETE': delete. statements, locking depends on whether the
     statement uses a unique index with a unique search condition (such
     as `WHERE id = 100'), or a range-type search condition (such as
     `WHERE id > 100'). For a unique index with a unique search
     condition, `InnoDB' locks only the index record found, not the gap
     before it. For range-type searches, `InnoDB' locks the index range
     scanned, using gap locks or next-key (gap plus index-record) locks
     to block insertions by other sessions into the gaps covered by the
     range. This is necessary because `phantom rows' must be blocked
     for MySQL replication and recovery to work.

   *  `REPEATABLE READ'

     This is the default isolation level for `InnoDB'. For consistent
     reads, there is an important difference from the `READ COMMITTED'
     isolation level: All consistent reads within the same transaction
     read the snapshot established by the first read. This convention
     means that if you issue several plain (nonlocking) *Note `SELECT':
     select. statements within the same transaction, these *Note
     `SELECT': select.  statements are consistent also with respect to
     each other. See *Note innodb-consistent-read::.

     For locking reads (*Note `SELECT': select. with `FOR UPDATE' or
     `LOCK IN SHARE MODE'), *Note `UPDATE': update, and *Note `DELETE':
     delete. statements, locking depends on whether the statement uses
     a unique index with a unique search condition, or a range-type
     search condition. For a unique index with a unique search
     condition, `InnoDB' locks only the index record found, not the gap
     before it. For other search conditions, `InnoDB' locks the index
     range scanned, using gap locks or next-key (gap plus index-record)
     locks to block insertions by other sessions into the gaps covered
     by the range.

   *  `SERIALIZABLE'

     This level is like `REPEATABLE READ', but `InnoDB' implicitly
     converts all plain *Note `SELECT': select.  statements to *Note
     `SELECT ... LOCK IN SHARE MODE': select. if autocommit is
     disabled. If autocommit is enabled, the *Note `SELECT': select. is
     its own transaction.  It therefore is known to be read only and
     can be serialized if performed as a consistent (nonlocking) read
     and need not block for other transactions. (This means that to
     force a plain *Note `SELECT': select. to block if other
     transactions have modified the selected rows, you should disable
     autocommit.)


File: manual.info,  Node: xa,  Prev: set-transaction,  Up: sql-syntax-transactions

13.3.7 XA Transactions
----------------------

* Menu:

* xa-statements::                XA Transaction SQL Syntax
* xa-states::                    XA Transaction States

MySQL 5.0.3 and up provides server-side support for XA transactions.
Currently, this support is available for the `InnoDB' storage engine.
The MySQL XA implementation is based on the X/Open CAE document
`Distributed Transaction Processing: The XA Specification'. This
document is published by The Open Group and available at
`http://www.opengroup.org/public/pubs/catalog/c193.htm'.  Limitations
of the current XA implementation are described in *Note
xa-restrictions::.

On the client side, there are no special requirements. The XA interface
to a MySQL server consists of SQL statements that begin with the `XA'
keyword. MySQL client programs must be able to send SQL statements and
to understand the semantics of the XA statement interface. They do not
need be linked against a recent client library. Older client libraries
also will work.

Currently, among the MySQL Connectors, MySQL Connector/J 5.0.0 supports
XA directly (by means of a class interface that handles the Xan SQL
statement interface for you).

XA supports distributed transactions; that is, the ability to permit
multiple separate transactional resources to participate in a global
transaction. Transactional resources often are RDBMSs but may be other
kinds of resources.

A global transaction involves several actions that are transactional in
themselves, but that all must either complete successfully as a group,
or all be rolled back as a group. In essence, this extends ACID
properties `up a level' so that multiple ACID transactions can be
executed in concert as components of a global operation that also has
ACID properties.  (However, for a distributed transaction, you must use
the `SERIALIZABLE' isolation level to achieve ACID properties. It is
enough to use `REPEATABLE READ' for a nondistributed transaction, but
not for a distributed transaction.)

Some examples of distributed transactions:

   * An application may act as an integration tool that combines a
     messaging service with an RDBMS. The application makes sure that
     transactions dealing with message sending, retrieval, and
     processing that also involve a transactional database all happen
     in a global transaction. You can think of this as `transactional
     email.'

   * An application performs actions that involve different database
     servers, such as a MySQL server and an Oracle server (or multiple
     MySQL servers), where actions that involve multiple servers must
     happen as part of a global transaction, rather than as separate
     transactions local to each server.

   * A bank keeps account information in an RDBMS and distributes and
     receives money through automated teller machines (ATMs).  It is
     necessary to ensure that ATM actions are correctly reflected in
     the accounts, but this cannot be done with the RDBMS alone. A
     global transaction manager integrates the ATM and database
     resources to ensure overall consistency of financial transactions.

Applications that use global transactions involve one or more Resource
Managers and a Transaction Manager:

   * A Resource Manager (RM) provides access to transactional
     resources. A database server is one kind of resource manager.  It
     must be possible to either commit or roll back transactions
     managed by the RM.

   * A Transaction Manager (TM) coordinates the transactions that are
     part of a global transaction. It communicates with the RMs that
     handle each of these transactions. The individual transactions
     within a global transaction are `branches' of the global
     transaction. Global transactions and their branches are identified
     by a naming scheme described later.

The MySQL implementation of XA MySQL enables a MySQL server to act as a
Resource Manager that handles XA transactions within a global
transaction. A client program that connects to the MySQL server acts as
the Transaction Manager.

To carry out a global transaction, it is necessary to know which
components are involved, and bring each component to a point when it
can be committed or rolled back. Depending on what each component
reports about its ability to succeed, they must all commit or roll back
as an atomic group. That is, either all components must commit, or all
components must roll back. To manage a global transaction, it is
necessary to take into account that any component or the connecting
network might fail.

The process for executing a global transaction uses two-phase commit
(2PC). This takes place after the actions performed by the branches of
the global transaction have been executed.

  1. In the first phase, all branches are prepared. That is, they are
     told by the TM to get ready to commit. Typically, this means each
     RM that manages a branch records the actions for the branch in
     stable storage. The branches indicate whether they are able to do
     this, and these results are used for the second phase.

  2. In the second phase, the TM tells the RMs whether to commit or
     roll back. If all branches indicated when they were prepared that
     they will be able to commit, all branches are told to commit. If
     any branch indicated when it was prepared that it will not be able
     to commit, all branches are told to roll back.

In some cases, a global transaction might use one-phase commit (1PC).
For example, when a Transaction Manager finds that a global transaction
consists of only one transactional resource (that is, a single branch),
that resource can be told to prepare and commit at the same time.


File: manual.info,  Node: xa-statements,  Next: xa-states,  Prev: xa,  Up: xa

13.3.7.1 XA Transaction SQL Syntax
..................................

To perform XA transactions in MySQL, use the following statements:

     XA {START|BEGIN} XID [JOIN|RESUME]

     XA END XID [SUSPEND [FOR MIGRATE]]

     XA PREPARE XID

     XA COMMIT XID [ONE PHASE]

     XA ROLLBACK XID

     XA RECOVER

For *Note `XA START': xa-statements, the `JOIN' and `RESUME' clauses
are not supported.

For *Note `XA END': xa-statements. the `SUSPEND [FOR MIGRATE]' clause
is not supported.

Each XA statement begins with the `XA' keyword, and most of them
require an XID value. An XID is an XA transaction identifier. It
indicates which transaction the statement applies to. XID values are
supplied by the client, or generated by the MySQL server. An XID value
has from one to three parts:

     XID: GTRID [, BQUAL [, FORMATID ]]

GTRID is a global transaction identifier, BQUAL is a branch qualifier,
and FORMATID is a number that identifies the format used by the GTRID
and BQUAL values. As indicated by the syntax, BQUAL and FORMATID are
optional. The default BQUAL value is `''' if not given. The default
FORMATID value is 1 if not given.

GTRID and BQUAL must be string literals, each up to 64 bytes (not
characters) long.  GTRID and BQUAL can be specified in several ways.
You can use a quoted string (`'ab''), hex string (`0x6162', `X'ab''), or
bit value (`b'NNNN'').

FORMATID is an unsigned integer.

The GTRID and BQUAL values are interpreted in bytes by the MySQL
server's underlying XA support routines. However, while an SQL
statement containing an XA statement is being parsed, the server works
with some specific character set. To be safe, write GTRID and BQUAL as
hex strings.

XID values typically are generated by the Transaction Manager. Values
generated by one TM must be different from values generated by other
TMs. A given TM must be able to recognize its own XID values in a list
of values returned by the *Note `XA RECOVER': xa-statements. statement.

`XA START XID' starts an XA transaction with the given XID value. Each
XA transaction must have a unique XID value, so the value must not
currently be used by another XA transaction. Uniqueness is assessed
using the GTRID and BQUAL values. All following XA statements for the
XA transaction must be specified using the same XID value as that given
in the *Note `XA START': xa-statements. statement. If you use any of
those statements but specify an XID value that does not correspond to
some existing XA transaction, an error occurs.

One or more XA transactions can be part of the same global transaction.
All XA transactions within a given global transaction must use the same
GTRID value in the XID value. For this reason, GTRID values must be
globally unique so that there is no ambiguity about which global
transaction a given XA transaction is part of. The BQUAL part of the
XID value must be different for each XA transaction within a global
transaction. (The requirement that BQUAL values be different is a
limitation of the current MySQL XA implementation. It is not part of
the XA specification.)

The *Note `XA RECOVER': xa-statements. statement returns information
for those XA transactions on the MySQL server that are in the
`PREPARED' state. (See *Note xa-states::.) The output includes a row
for each such XA transaction on the server, regardless of which client
started it.

*Note `XA RECOVER': xa-statements. output rows look like this (for an
example XID value consisting of the parts `'abc'', `'def'', and `7'):

     mysql> XA RECOVER;
     +----------+--------------+--------------+--------+
     | formatID | gtrid_length | bqual_length | data   |
     +----------+--------------+--------------+--------+
     |        7 |            3 |            3 | abcdef |
     +----------+--------------+--------------+--------+

The output columns have the following meanings:

   * `formatID' is the FORMATID part of the transaction XID

   * `gtrid_length' is the length in bytes of the GTRID part of the XID

   * `bqual_length' is the length in bytes of the BQUAL part of the XID

   * `data' is the concatenation of the GTRID and BQUAL parts of the XID


File: manual.info,  Node: xa-states,  Prev: xa-statements,  Up: xa

13.3.7.2 XA Transaction States
..............................

An XA transaction progresses through the following states:

  1. Use *Note `XA START': xa-statements. to start an XA transaction
     and put it in the `ACTIVE' state.

  2. For an `ACTIVE' XA transaction, issue the SQL statements that make
     up the transaction, and then issue an *Note `XA END':
     xa-statements. statement.  *Note `XA END': xa-statements. puts the
     transaction in the `IDLE' state.

  3. For an `IDLE' XA transaction, you can issue either an *Note `XA
     PREPARE': xa-statements. statement or an `XA COMMIT ... ONE PHASE'
     statement:

        * *Note `XA PREPARE': xa-statements. puts the transaction in the
          `PREPARED' state. An *Note `XA RECOVER': xa-statements.
          statement at this point will include the transaction's XID
          value in its output, because *Note `XA RECOVER':
          xa-statements. lists all XA transactions that are in the
          `PREPARED' state.

        * `XA COMMIT ... ONE PHASE' prepares and commits the
          transaction. The XID value will not be listed by *Note `XA
          RECOVER': xa-statements. because the transaction terminates.

  4. For a `PREPARED' XA transaction, you can issue an *Note `XA
     COMMIT': xa-statements. statement to commit and terminate the
     transaction, or *Note `XA ROLLBACK': xa-statements. to roll back
     and terminate the transaction.

Here is a simple XA transaction that inserts a row into a table as part
of a global transaction:

     mysql> XA START 'xatest';
     Query OK, 0 rows affected (0.00 sec)

     mysql> INSERT INTO mytable (i) VALUES(10);
     Query OK, 1 row affected (0.04 sec)

     mysql> XA END 'xatest';
     Query OK, 0 rows affected (0.00 sec)

     mysql> XA PREPARE 'xatest';
     Query OK, 0 rows affected (0.00 sec)

     mysql> XA COMMIT 'xatest';
     Query OK, 0 rows affected (0.00 sec)

Within the context of a given client connection, XA transactions and
local (non-XA) transactions are mutually exclusive. For example, if
*Note `XA START': xa-statements. has been issued to begin an XA
transaction, a local transaction cannot be started until the XA
transaction has been committed or rolled back. Conversely, if a local
transaction has been started with *Note `START TRANSACTION': commit, no
XA statements can be used until the transaction has been committed or
rolled back.

Note that if an XA transaction is in the `ACTIVE' state, you cannot
issue any statements that cause an implicit commit. That would violate
the XA contract because you could not roll back the XA transaction. You
will receive the following error if you try to execute such a statement:

     ERROR 1399 (XAE07): XAER_RMFAIL: The command cannot be executed
     when global transaction is in the ACTIVE state

Statements to which the preceding remark applies are listed at *Note
implicit-commit::.


File: manual.info,  Node: sql-syntax-replication,  Next: sql-syntax-prepared-statements,  Prev: sql-syntax-transactions,  Up: sql-syntax

13.4 Replication Statements
===========================

* Menu:

* replication-master-sql::       SQL Statements for Controlling Master Servers
* replication-slave-sql::        SQL Statements for Controlling Slave Servers

Replication can be controlled through the SQL interface using the
statements described in this section. One group of statements controls
master servers, the other controls slave servers.


File: manual.info,  Node: replication-master-sql,  Next: replication-slave-sql,  Prev: sql-syntax-replication,  Up: sql-syntax-replication

13.4.1 SQL Statements for Controlling Master Servers
----------------------------------------------------

* Menu:

* purge-binary-logs::            `PURGE BINARY LOGS' Syntax
* reset-master::                 `RESET MASTER' Syntax
* set-sql-log-bin::              `SET sql_log_bin' Syntax

This section discusses statements for managing master replication
servers. *Note replication-slave-sql::, discusses statements for
managing slave servers.

In addition to the statements described here, the following *Note
`SHOW': show. statements are used with master servers in replication.
For information about these statements, see *Note show::.

   * *Note `SHOW BINARY LOGS': show-binary-logs.

   * *Note `SHOW BINLOG EVENTS': show-binlog-events.

   * *Note `SHOW MASTER STATUS': show-master-status.

   * *Note `SHOW SLAVE HOSTS': show-slave-hosts.


File: manual.info,  Node: purge-binary-logs,  Next: reset-master,  Prev: replication-master-sql,  Up: replication-master-sql

13.4.1.1 `PURGE BINARY LOGS' Syntax
...................................

     PURGE { BINARY | MASTER } LOGS
         { TO 'LOG_NAME' | BEFORE DATETIME_EXPR }

The binary log is a set of files that contain information about data
modifications made by the MySQL server. The log consists of a set of
binary log files, plus an index file (see *Note binary-log::).

The *Note `PURGE BINARY LOGS': purge-binary-logs. statement deletes all
the binary log files listed in the log index file prior to the
specified log file name or date.  `BINARY' and `MASTER' are synonyms.
Deleted log files also are removed from the list recorded in the index
file, so that the given log file becomes the first in the list.

This statement has no effect if the server was not started with the
`--log-bin' option to enable binary logging.

Examples:

     PURGE BINARY LOGS TO 'mysql-bin.010';
     PURGE BINARY LOGS BEFORE '2008-04-02 22:46:26';

The `BEFORE' variant's DATETIME_EXPR argument should evaluate to a
*Note `DATETIME': datetime. value (a value in `'YYYY-MM-DD hh:mm:ss''
format).

This statement is safe to run while slaves are replicating. You need
not stop them. If you have an active slave that currently is reading
one of the log files you are trying to delete, this statement does
nothing and fails with an error. However, if a slave is not connected
and you happen to purge one of the log files it has yet to read, the
slave will be unable to replicate after it reconnects.

To safely purge binary log files, follow this procedure:

  1. On each slave server, use *Note `SHOW SLAVE STATUS':
     show-slave-status. to check which log file it is reading.

  2. Obtain a listing of the binary log files on the master server with
     *Note `SHOW BINARY LOGS': show-binary-logs.

  3. Determine the earliest log file among all the slaves. This is the
     target file. If all the slaves are up to date, this is the last
     log file on the list.

  4. Make a backup of all the log files you are about to delete.  (This
     step is optional, but always advisable.)

  5. Purge all log files up to but not including the target file.

You can also set the `expire_logs_days' system variable to expire
binary log files automatically after a given number of days (see *Note
server-system-variables::).  If you are using replication, you should
set the variable no lower than the maximum number of days your slaves
might lag behind the master.

Prior to MySQL 5.0.60, `PURGE BINARY LOGS TO' and `PURGE BINARY LOGS
BEFORE' did not behave in the same way (and neither one behaved
correctly) when binary log files listed in the `.index' file had been
removed from the system by some other means (such as using `rm' on
Linux). Beginning with MySQL 5.0.60, both variants of the statement
fail with an error in such cases.  (Bug #18199, Bug #18453) To handle
such errors, edit the `.index' file (which is a simple text file)
manually to ensure that it lists only the binary log files that are
actually present, then run again the *Note `PURGE BINARY LOGS':
purge-binary-logs. statement that failed.


File: manual.info,  Node: reset-master,  Next: set-sql-log-bin,  Prev: purge-binary-logs,  Up: replication-master-sql

13.4.1.2 `RESET MASTER' Syntax
..............................

     RESET MASTER

Deletes all binary log files listed in the index file, resets the
binary log index file to be empty, and creates a new binary log file.
This statement is intended to be used only when the master is started
for the first time.

*Important*:

The effects of *Note `RESET MASTER': reset-master.  differ from those
of *Note `PURGE BINARY LOGS': purge-binary-logs. in 2 key ways:

  1. *Note `RESET MASTER': reset-master. removes _all_ binary log files
     that are listed in the index file, leaving only a single, empty
     binary log file with a numeric suffix of `.000001', whereas the
     numbering is not reset by *Note `PURGE BINARY LOGS':
     purge-binary-logs.

  2. *Note `RESET MASTER': reset-master. is _not_ intended to be used
     while any replication slaves are running. The behavior of *Note
     `RESET MASTER': reset-master. when used while slaves are running
     is undefined (and thus unsupported), whereas *Note `PURGE BINARY
     LOGS': purge-binary-logs. may be safely used while replication
     slaves are running.

See also *Note purge-binary-logs::.

*Note `RESET MASTER': reset-master. can prove useful when you first set
up the master and the slave, so that you can verify the setup as
follows:

  1. Start the master and slave, and start replication (see *Note
     replication-howto::).

  2. Execute a few test queries on the master.

  3. Check that the queries were replicated to the slave.

  4. When replication is running correctly, issue *Note `STOP SLAVE':
     stop-slave. followed by *Note `RESET SLAVE': reset-slave. on the
     slave, then verify that any unwanted data no longer exists on the
     slave.

  5. Issue *Note `RESET MASTER': reset-master. on the master to clean
     up the test queries.

After verifying the setup and getting rid of any unwanted and log files
generated by testing, you can start the slave and begin replicating.


File: manual.info,  Node: set-sql-log-bin,  Prev: reset-master,  Up: replication-master-sql

13.4.1.3 `SET sql_log_bin' Syntax
.................................

     SET sql_log_bin = {0|1}

Disables or enables binary logging for the current session
(`sql_log_bin' is a session variable) if the client has the `SUPER'
privilege. The statement fails with an error if the client does not
have that privilege.


File: manual.info,  Node: replication-slave-sql,  Prev: replication-master-sql,  Up: sql-syntax-replication

13.4.2 SQL Statements for Controlling Slave Servers
---------------------------------------------------

* Menu:

* change-master-to::             `CHANGE MASTER TO' Syntax
* load-data-from-master::        `LOAD DATA FROM MASTER' Syntax
* load-table-from-master::       `LOAD TABLE TBL_NAME FROM MASTER' Syntax
* master-pos-wait::              `MASTER_POS_WAIT()' Syntax
* reset-slave::                  `RESET SLAVE' Syntax
* set-global-sql-slave-skip-counter::  `SET GLOBAL sql_slave_skip_counter' Syntax
* start-slave::                  `START SLAVE' Syntax
* stop-slave::                   `STOP SLAVE' Syntax

This section discusses statements for managing slave replication
servers. *Note replication-master-sql::, discusses statements for
managing master servers.

In addition to the statements described here, *Note `SHOW SLAVE
STATUS': show-slave-status. is also used with replication slaves. For
information about this statement, see *Note show-slave-status::.


File: manual.info,  Node: change-master-to,  Next: load-data-from-master,  Prev: replication-slave-sql,  Up: replication-slave-sql

13.4.2.1 `CHANGE MASTER TO' Syntax
..................................

     CHANGE MASTER TO OPTION [, OPTION] ...

     OPTION:
         MASTER_HOST = 'HOST_NAME'
       | MASTER_USER = 'USER_NAME'
       | MASTER_PASSWORD = 'PASSWORD'
       | MASTER_PORT = PORT_NUM
       | MASTER_CONNECT_RETRY = INTERVAL
       | MASTER_LOG_FILE = 'MASTER_LOG_NAME'
       | MASTER_LOG_POS = MASTER_LOG_POS
       | RELAY_LOG_FILE = 'RELAY_LOG_NAME'
       | RELAY_LOG_POS = RELAY_LOG_POS
       | MASTER_SSL = {0|1}
       | MASTER_SSL_CA = 'CA_FILE_NAME'
       | MASTER_SSL_CAPATH = 'CA_DIRECTORY_NAME'
       | MASTER_SSL_CERT = 'CERT_FILE_NAME'
       | MASTER_SSL_KEY = 'KEY_FILE_NAME'
       | MASTER_SSL_CIPHER = 'CIPHER_LIST'

*Note `CHANGE MASTER TO': change-master-to. changes the parameters that
the slave server uses for connecting to the master server, for reading
the master binary log, and reading the slave relay log. It also updates
the contents of the `master.info' and `relay-log.info' files. To use
*Note `CHANGE MASTER TO': change-master-to, the slave replication
threads must be stopped (use *Note `STOP SLAVE': stop-slave. if
necessary).

Options not specified retain their value, except as indicated in the
following discussion. Thus, in most cases, there is no need to specify
options that do not change. For example, if the password to connect to
your MySQL master has changed, you just need to issue these statements
to tell the slave about the new password:

     STOP SLAVE; -- if replication was running
     CHANGE MASTER TO MASTER_PASSWORD='new3cret';
     START SLAVE; -- if you want to restart replication

`MASTER_HOST', `MASTER_USER', `MASTER_PASSWORD', and `MASTER_PORT'
provide information to the slave about how to connect to its master:

   * `MASTER_HOST' and `MASTER_PORT' are the host name (or IP address)
     of the master host and its TCP/IP port.

     *Note*:

     Replication cannot use Unix socket files. You must be able to
     connect to the master MySQL server using TCP/IP.

     If you specify the `MASTER_HOST' or `MASTER_PORT' option, the
     slave assumes that the master server is different from before
     (even if the option value is the same as its current value.) In
     this case, the old values for the master binary log file name and
     position are considered no longer applicable, so if you do not
     specify `MASTER_LOG_FILE' and `MASTER_LOG_POS' in the statement,
     `MASTER_LOG_FILE=''' and `MASTER_LOG_POS=4' are silently appended
     to it.

     Setting `MASTER_HOST='''--that is, setting its value explicitly to
     an empty string--is _not_ the same as not setting it at all.
     Setting this option to an empty string causes *Note `START SLAVE':
     start-slave. subsequently to fail. (Bug #28796)

   * `MASTER_USER' and `MASTER_PASSWORD' are the user name and password
     of the account to use for connecting to the master.

     The text of a running *Note `CHANGE MASTER TO': change-master-to.
     statement, including values for `MASTER_USER' and
     `MASTER_PASSWORD', can be seen in the output of a concurrent *Note
     `SHOW PROCESSLIST': show-processlist. statement.

The `MASTER_SSL_XXX' options provide information about using SSL for
the connection.  They correspond to the `--ssl-XXX' options described
in *Note ssl-options::, and *Note replication-solutions-ssl::. These
options can be changed even on slaves that are compiled without SSL
support.  They are saved to the `master.info' file, but are ignored if
the slave does not have SSL support enabled.

`MASTER_CONNECT_RETRY' specifies how many seconds to wait between
connect retries. The default is 60. The _number_ of reconnection
attempts is limited by the `--master-retry-count' server option; for
more information, see *Note replication-options::.

`MASTER_LOG_FILE' and `MASTER_LOG_POS' are the coordinates at which the
slave I/O thread should begin reading from the master the next time the
thread starts. `RELAY_LOG_FILE' and `RELAY_LOG_POS' are the coordinates
at which the slave SQL thread should begin reading from the relay log
the next time the thread starts. If you specify either of
`MASTER_LOG_FILE' or `MASTER_LOG_POS', you cannot specify
`RELAY_LOG_FILE' or `RELAY_LOG_POS'. If neither of `MASTER_LOG_FILE' or
`MASTER_LOG_POS' is specified, the slave uses the last coordinates of
the _slave SQL thread_ before *Note `CHANGE MASTER TO':
change-master-to. was issued. This ensures that there is no
discontinuity in replication, even if the slave SQL thread was late
compared to the slave I/O thread, when you merely want to change, say,
the password to use.

*Note `CHANGE MASTER TO': change-master-to.  _deletes all relay log
files_ and starts a new one, unless you specify `RELAY_LOG_FILE' or
`RELAY_LOG_POS'. In that case, relay log files are kept; the
`relay_log_purge' global variable is set silently to 0.

*Note `CHANGE MASTER TO': change-master-to. is useful for setting up a
slave when you have the snapshot of the master and have recorded the
master binary log coordinates corresponding to the time of the
snapshot. After loading the snapshot into the slave to synchronize it
to the slave, you can run `CHANGE MASTER TO MASTER_LOG_FILE='LOG_NAME',
MASTER_LOG_POS=LOG_POS' on the slave to specify the coordinates at
which the slave should begin reading the master binary log.

The following example changes the master server the slave uses and
establishes the master binary log coordinates from which the slave
begins reading. This is used when you want to set up the slave to
replicate the master:

     CHANGE MASTER TO
       MASTER_HOST='master2.mycompany.com',
       MASTER_USER='replication',
       MASTER_PASSWORD='bigs3cret',
       MASTER_PORT=3306,
       MASTER_LOG_FILE='master2-bin.001',
       MASTER_LOG_POS=4,
       MASTER_CONNECT_RETRY=10;

The next example shows an operation that is less frequently employed.
It is used when the slave has relay log files that you want it to
execute again for some reason. To do this, the master need not be
reachable. You need only use *Note `CHANGE MASTER TO':
change-master-to. and start the SQL thread (`START SLAVE SQL_THREAD'):

     CHANGE MASTER TO
       RELAY_LOG_FILE='slave-relay-bin.006',
       RELAY_LOG_POS=4025;

You can even use the second operation in a nonreplication setup with a
standalone, nonslave server for recovery following a crash. Suppose
that your server has crashed and you have restored it from a backup.
You want to replay the server's own binary log files (not relay log
files, but regular binary log files), named (for example)
`myhost-bin.*'.  First, make a backup copy of these binary log files in
some safe place, in case you don't exactly follow the procedure below
and accidentally have the server purge the binary log. Use `SET GLOBAL
relay_log_purge=0' for additional safety. Then start the server without
the `--log-bin' option, Instead, use the `--replicate-same-server-id',
`--relay-log=myhost-bin' (to make the server believe that these regular
binary log files are relay log files) and `--skip-slave-start' options.
After the server starts, issue these statements:

     CHANGE MASTER TO
       RELAY_LOG_FILE='myhost-bin.153',
       RELAY_LOG_POS=410,
       MASTER_HOST='some_dummy_string';
     START SLAVE SQL_THREAD;

The server reads and executes its own binary log files, thus achieving
crash recovery. Once the recovery is finished, run *Note `STOP SLAVE':
stop-slave, shut down the server, delete the `master.info' and
`relay-log.info' files, and restart the server with its original
options.

Specifying the `MASTER_HOST' option (even with a dummy value) is
required to make the server think it is a slave.


File: manual.info,  Node: load-data-from-master,  Next: load-table-from-master,  Prev: change-master-to,  Up: replication-slave-sql

13.4.2.2 `LOAD DATA FROM MASTER' Syntax
.......................................

     LOAD DATA FROM MASTER

*This feature is deprecated and should be avoided. It is subject to
removal in a future version of MySQL.*

Since the current implementation of `LOAD DATA FROM MASTER' and `LOAD
TABLE FROM MASTER' is very limited, these statements are deprecated as
of MySQL 4.1 and removed in MySQL 5.5.

The recommended alternative solution to using `LOAD DATA FROM MASTER'
or `LOAD TABLE FROM MASTER' is using *Note `mysqldump': mysqldump. or
*Note `mysqlhotcopy': mysqlhotcopy. The latter requires Perl and two
Perl modules (`DBI' and `DBD:mysql') and works for `MyISAM' and
`ARCHIVE' tables only. With *Note `mysqldump': mysqldump, you can
create SQL dumps on the master and pipe (or copy) these to a *Note
`mysql': mysql. client on the slave. This has the advantage of working
for all storage engines, but can be quite slow, since it works using
*Note `SELECT': select.

This statement takes a snapshot of the master and copies it to the
slave. It updates the values of `MASTER_LOG_FILE' and `MASTER_LOG_POS'
so that the slave starts replicating from the correct position. Any
table and database exclusion rules specified with the
`--replicate-*-do-*' and `--replicate-*-ignore-*' options are honored.
`--replicate-rewrite-db' is _not_ taken into account because a user
could use this option to set up a nonunique mapping such as
`--replicate-rewrite-db="db1->db3"' and
`--replicate-rewrite-db="db2->db3"', which would confuse the slave when
loading tables from the master.

Use of this statement is subject to the following conditions:

   * It works only for `MyISAM' tables.  Attempting to load a
     non-`MyISAM' table results in the following error:

          ERROR 1189 (08S01): Net error reading from master

   * It acquires a global read lock on the master while taking the
     snapshot, which prevents updates on the master during the load
     operation.

If you are loading large tables, you might have to increase the values
of `net_read_timeout' and `net_write_timeout' on both the master and
slave servers. See *Note server-system-variables::.

Note that `LOAD DATA FROM MASTER' does _not_ copy any tables from the
`mysql' database. This makes it easy to have different users and
privileges on the master and the slave.

To use `LOAD DATA FROM MASTER', the replication account that is used to
connect to the master must have the `RELOAD' and `SUPER' privileges on
the master and the `SELECT' privilege for all master tables you want to
load. All master tables for which the user does not have the `SELECT'
privilege are ignored by `LOAD DATA FROM MASTER'. This is because the
master hides them from the user: `LOAD DATA FROM MASTER' calls *Note
`SHOW DATABASES': show-databases. to know the master databases to load,
but *Note `SHOW DATABASES': show-databases. returns only databases for
which the user has some privilege. See *Note show-databases::. On the
slave side, the user that issues `LOAD DATA FROM MASTER' must have
privileges for dropping and creating the databases and tables that are
copied.


File: manual.info,  Node: load-table-from-master,  Next: master-pos-wait,  Prev: load-data-from-master,  Up: replication-slave-sql

13.4.2.3 `LOAD TABLE TBL_NAME FROM MASTER' Syntax
.................................................

     LOAD TABLE TBL_NAME FROM MASTER

*This feature is deprecated and should be avoided. It is subject to
removal in a future version of MySQL.*

Since the current implementation of `LOAD DATA FROM MASTER' and `LOAD
TABLE FROM MASTER' is very limited, these statements are deprecated as
of MySQL 4.1 and removed in MySQL 5.5.

The recommended alternative solution to using `LOAD DATA FROM MASTER'
or `LOAD TABLE FROM MASTER' is using *Note `mysqldump': mysqldump. or
*Note `mysqlhotcopy': mysqlhotcopy. The latter requires Perl and two
Perl modules (`DBI' and `DBD:mysql') and works for `MyISAM' and
`ARCHIVE' tables only. With *Note `mysqldump': mysqldump, you can
create SQL dumps on the master and pipe (or copy) these to a *Note
`mysql': mysql. client on the slave. This has the advantage of working
for all storage engines, but can be quite slow, since it works using
*Note `SELECT': select.

Transfers a copy of the table from the master to the slave. This
statement is implemented mainly debugging `LOAD DATA FROM MASTER'
operations. To use `LOAD TABLE', the account used for connecting to the
master server must have the `RELOAD' and `SUPER' privileges on the
master and the `SELECT' privilege for the master table to load. On the
slave side, the user that issues `LOAD TABLE FROM MASTER' must have
privileges for dropping and creating the table.

The conditions for `LOAD DATA FROM MASTER' apply here as well. For
example, `LOAD TABLE FROM MASTER' works only for `MyISAM' tables. The
timeout notes for `LOAD DATA FROM MASTER' apply as well.


File: manual.info,  Node: master-pos-wait,  Next: reset-slave,  Prev: load-table-from-master,  Up: replication-slave-sql

13.4.2.4 `MASTER_POS_WAIT()' Syntax
...................................

     SELECT MASTER_POS_WAIT('MASTER_LOG_FILE', MASTER_LOG_POS [, TIMEOUT])

This is actually a function, not a statement. It is used to ensure that
the slave has read and executed events up to a given position in the
master's binary log. See *Note miscellaneous-functions::, for a full
description.

The following table shows the maximum permissible length for the
string-valued options.

Option         Maximum Length
`MASTER_HOST'  60
`MASTER_USER'  16
`MASTER_PASSWORD'32
`MASTER_LOG_FILE'255
`RELAY_LOG_FILE'255
`MASTER_SSL_CA'255
`MASTER_SSL_CAPATH'255
`MASTER_SSL_CERT'255
`MASTER_SSL_KEY'255
`MASTER_SSL_CIPHER'511


File: manual.info,  Node: reset-slave,  Next: set-global-sql-slave-skip-counter,  Prev: master-pos-wait,  Up: replication-slave-sql

13.4.2.5 `RESET SLAVE' Syntax
.............................

     RESET SLAVE

*Note `RESET SLAVE': reset-slave. makes the slave forget its
replication position in the master's binary log. This statement is
meant to be used for a clean start: It deletes the `master.info' and
`relay-log.info' files, all the relay log files, and starts a new relay
log file. To use *Note `RESET SLAVE': reset-slave, the slave
replication threads must be stopped (use *Note `STOP SLAVE':
stop-slave. if necessary).

*Note*:

All relay log files are deleted, even if they have not been completely
executed by the slave SQL thread. (This is a condition likely to exist
on a replication slave if you have issued a *Note `STOP SLAVE':
stop-slave. statement or if the slave is highly loaded.)

Connection information stored in the `master.info' file is immediately
reset using any values specified in the corresponding startup options.
This information includes values such as master host, master port,
master user, and master password. If the slave SQL thread was in the
middle of replicating temporary tables when it was stopped, and *Note
`RESET SLAVE': reset-slave. is issued, these replicated temporary
tables are deleted on the slave.


File: manual.info,  Node: set-global-sql-slave-skip-counter,  Next: start-slave,  Prev: reset-slave,  Up: replication-slave-sql

13.4.2.6 `SET GLOBAL sql_slave_skip_counter' Syntax
...................................................

     SET GLOBAL sql_slave_skip_counter = N

This statement skips the next N events from the master. This is useful
for recovering from replication stops caused by a statement.

This statement is valid only when the slave threads are not running.
Otherwise, it produces an error.

When using this statement, it is important to understand that the
binary log is actually organized as a sequence of groups known as
_event groups_. Each event group consists of a sequence of events.

   * For transactional tables, an event group corresponds to a
     transaction.

   * For nontransactional tables, an event group corresponds to a
     single SQL statement.

*Note*:

A single transaction can contain changes to both transactional and
nontransactional tables.

When you use `SET GLOBAL sql_slave_skip_counter' to skip events and the
result is in the middle of a group, the slave continues to skip events
until it reaches the end of the group. Execution then starts with the
next event group.


File: manual.info,  Node: start-slave,  Next: stop-slave,  Prev: set-global-sql-slave-skip-counter,  Up: replication-slave-sql

13.4.2.7 `START SLAVE' Syntax
.............................

     START SLAVE [THREAD_TYPE [, THREAD_TYPE] ... ]
     START SLAVE [SQL_THREAD] UNTIL
         MASTER_LOG_FILE = 'LOG_NAME', MASTER_LOG_POS = LOG_POS
     START SLAVE [SQL_THREAD] UNTIL
         RELAY_LOG_FILE = 'LOG_NAME', RELAY_LOG_POS = LOG_POS

     THREAD_TYPE: IO_THREAD | SQL_THREAD

*Note `START SLAVE': start-slave. with no THREAD_TYPE options starts
both of the slave threads. The I/O thread reads events from the master
server and stores them in the relay log. The SQL thread reads events
from the relay log and executes them.  *Note `START SLAVE':
start-slave. requires the `SUPER' privilege.

If *Note `START SLAVE': start-slave. succeeds in starting the slave
threads, it returns without any error.  However, even in that case, it
might be that the slave threads start and then later stop (for example,
because they do not manage to connect to the master or read its binary
log, or some other problem). *Note `START SLAVE': start-slave. does not
warn you about this. You must check the slave's error log for error
messages generated by the slave threads, or check that they are running
satisfactorily with *Note `SHOW SLAVE STATUS': show-slave-status.

*Note `START SLAVE': start-slave. sends an acknowledgment to the user
after both the I/O thread and the SQL thread have started. However, the
I/O thread may not yet have connected. For this reason, a successful
*Note `START SLAVE': start-slave. causes *Note `SHOW SLAVE STATUS':
show-slave-status. to show `Slave_SQL_Running=Yes', but this does not
guarantee that `Slave_IO_Running=Yes' (because `Slave_IO_Running=Yes'
only if the I/O thread is running _and connected_). For more
information, see *Note show-slave-status::, and *Note
replication-administration-status::.

You can add `IO_THREAD' and `SQL_THREAD' options to the statement to
name which of the threads to start.

An `UNTIL' clause may be added to specify that the slave should start
and run until the SQL thread reaches a given point in the master binary
log or in the slave relay log.  When the SQL thread reaches that point,
it stops. If the `SQL_THREAD' option is specified in the statement, it
starts only the SQL thread. Otherwise, it starts both slave threads. If
the SQL thread is running, the `UNTIL' clause is ignored and a warning
is issued.

For an `UNTIL' clause, you must specify both a log file name and
position. Do not mix master and relay log options.

Any `UNTIL' condition is reset by a subsequent *Note `STOP SLAVE':
stop-slave. statement, a *Note `START SLAVE': start-slave. statement
that includes no `UNTIL' clause, or a server restart.

The `UNTIL' clause can be useful for debugging replication, or to cause
replication to proceed until just before the point where you want to
avoid having the slave replicate an event. For example, if an unwise
*Note `DROP TABLE': drop-table. statement was executed on the master,
you can use `UNTIL' to tell the slave to execute up to that point but
no farther. To find what the event is, use *Note `mysqlbinlog':
mysqlbinlog. with the master binary log or slave relay log, or by using
a *Note `SHOW BINLOG EVENTS': show-binlog-events. statement.

If you are using `UNTIL' to have the slave process replicated queries
in sections, it is recommended that you start the slave with the
`--skip-slave-start' option to prevent the SQL thread from running when
the slave server starts. It is probably best to use this option in an
option file rather than on the command line, so that an unexpected
server restart does not cause it to be forgotten.

The *Note `SHOW SLAVE STATUS': show-slave-status. statement includes
output fields that display the current values of the `UNTIL' condition.

In old versions of MySQL (before 4.0.5), this statement was called
`SLAVE START'. This usage is still accepted in MySQL 5.0 for backward
compatibility, but is deprecated and is removed in MySQL 5.6.


File: manual.info,  Node: stop-slave,  Prev: start-slave,  Up: replication-slave-sql

13.4.2.8 `STOP SLAVE' Syntax
............................

     STOP SLAVE [THREAD_TYPE [, THREAD_TYPE] ... ]

     THREAD_TYPE: IO_THREAD | SQL_THREAD

Stops the slave threads. *Note `STOP SLAVE': stop-slave. requires the
`SUPER' privilege.

Like *Note `START SLAVE': start-slave, this statement may be used with
the `IO_THREAD' and `SQL_THREAD' options to name the thread or threads
to be stopped.

*Note*:

The transactional behavior of *Note `STOP SLAVE': stop-slave. changed
in MySQL 5.0.82. Previously, it took effect immediately; beginning with
MySQL 5.0.82, it waits until the current replication event group (if
any) has finished executing, or until the user issues a *Note `KILL
QUERY': kill. or *Note `KILL CONNECTION': kill. statement. (Bug #319,
Bug #38205)

In old versions of MySQL (before 4.0.5), this statement was called
`SLAVE STOP'. This usage is still accepted in MySQL 5.0 for backward
compatibility, but is deprecated and is removed in MySQL 5.6.


File: manual.info,  Node: sql-syntax-prepared-statements,  Next: sql-syntax-compound-statements,  Prev: sql-syntax-replication,  Up: sql-syntax

13.5 SQL Syntax for Prepared Statements
=======================================

* Menu:

* prepare::                      `PREPARE' Syntax
* execute::                      `EXECUTE' Syntax
* deallocate-prepare::           `DEALLOCATE PREPARE' Syntax

MySQL 5.0 provides support for server-side prepared statements. This
support takes advantage of the efficient client/server binary protocol
implemented in MySQL 4.1, provided that you use an appropriate client
programming interface. Candidate interfaces include the MySQL C API
client library (for C programs), MySQL Connector/J (for Java programs),
and MySQL Connector/Net. For example, the C API provides a set of
function calls that make up its prepared statement API. See *Note
c-api-prepared-statements::. Other language interfaces can provide
support for prepared statements that use the binary protocol by linking
in the C client library, one example being the `mysqli' extension
(http://php.net/mysqli), available in PHP 5.0 and later.

An alternative SQL interface to prepared statements is available.  This
interface is not as efficient as using the binary protocol through a
prepared statement API, but requires no programming because it is
available directly at the SQL level:

   * You can use it when no programming interface is available to you.

   * You can use it from any program that enables you to send SQL
     statements to the server to be executed, such as the *Note
     `mysql': mysql. client program.

   * You can use it even if the client is using an old version of the
     client library. The only requirement is that you be able to
     connect to a server that is recent enough to support SQL syntax
     for prepared statements.

SQL syntax for prepared statements is intended to be used for
situations such as these:

   * You want to test how prepared statements work in your application
     before coding it.

   * An application has problems executing prepared statements and you
     want to determine interactively what the problem is.

   * You want to create a test case that describes a problem you are
     having with prepared statements, so that you can file a bug report.

   * You need to use prepared statements but do not have access to a
     programming API that supports them.

SQL syntax for prepared statements is based on three SQL statements:

   * *Note `PREPARE': prepare. prepares a statement for execution (see
     *Note prepare::).

   * *Note `EXECUTE': execute. executes a prepared statement (see *Note
     execute::).

   * *Note `DEALLOCATE PREPARE': deallocate-prepare. releases a
     prepared statement (see *Note deallocate-prepare::).

The following examples show two equivalent ways of preparing a
statement that computes the hypotenuse of a triangle given the lengths
of the two sides.

The first example shows how to create a prepared statement by using a
string literal to supply the text of the statement:

     mysql> PREPARE stmt1 FROM 'SELECT SQRT(POW(?,2) + POW(?,2)) AS hypotenuse';
     mysql> SET @a = 3;
     mysql> SET @b = 4;
     mysql> EXECUTE stmt1 USING @a, @b;
     +------------+
     | hypotenuse |
     +------------+
     |          5 |
     +------------+
     mysql> DEALLOCATE PREPARE stmt1;

The second example is similar, but supplies the text of the statement
as a user variable:

     mysql> SET @s = 'SELECT SQRT(POW(?,2) + POW(?,2)) AS hypotenuse';
     mysql> PREPARE stmt2 FROM @s;
     mysql> SET @a = 6;
     mysql> SET @b = 8;
     mysql> EXECUTE stmt2 USING @a, @b;
     +------------+
     | hypotenuse |
     +------------+
     |         10 |
     +------------+
     mysql> DEALLOCATE PREPARE stmt2;

Here is an additional example which demonstrates how to choose the
table on which to perform a query at run time, by storing the name of
the table as a user variable:

     mysql> USE test;
     mysql> CREATE TABLE t1 (a INT NOT NULL);
     mysql> INSERT INTO t1 VALUES (4), (8), (11), (32), (80);

     mysql> SET @table = 't1';
     mysql> SET @s = CONCAT('SELECT * FROM ', @table);

     mysql> PREPARE stmt3 FROM @s;
     mysql> EXECUTE stmt3;
     +----+
     | a  |
     +----+
     |  4 |
     |  8 |
     | 11 |
     | 32 |
     | 80 |
     +----+

     mysql> DEALLOCATE PREPARE stmt3;

A prepared statement is specific to the session in which it was
created. If you terminate a session without deallocating a previously
prepared statement, the server deallocates it automatically.

A prepared statement is also global to the session. If you create a
prepared statement within a stored routine, it is not deallocated when
the stored routine ends.

To guard against too many prepared statements being created
simultaneously, set the `max_prepared_stmt_count' system variable. To
prevent the use of prepared statements, set the value to 0.

The following SQL statements can be used in prepared statements: *Note
`ALTER TABLE': alter-table, *Note `CALL': call, *Note `COMMIT': commit,
*Note `CREATE INDEX': create-index, *Note `CREATE TABLE': create-table,
*Note `DELETE': delete, *Note `DO': do, *Note `DROP INDEX': drop-index,
*Note `DROP TABLE': drop-table, *Note `INSERT': insert, *Note `RENAME
TABLE': rename-table, *Note `REPLACE': replace, *Note `SELECT': select,
*Note `SET': set-option, *Note `UPDATE': update, and most *Note `SHOW':
show. statements.  *Note `ANALYZE TABLE': analyze-table, *Note
`OPTIMIZE TABLE': optimize-table, and *Note `REPAIR TABLE':
repair-table. are also supported as of MySQL 5.0.23.

Other statements are not yet supported.

Generally, statements not permitted in SQL prepared statements are also
not permitted in stored programs. Exceptions are noted in *Note
stored-program-restrictions::.

As of MySQL 5.0.7, placeholders can be used for the arguments of the
`LIMIT' clause when using prepared statements. See *Note select::.

In prepared *Note `CALL': call. statements used with *Note `PREPARE':
prepare. and *Note `EXECUTE': execute, placeholder support for `OUT'
and `INOUT' parameters is not available in MySQL 5.0. See *Note call::,
for an example and a workaround. Placeholders can be used for `IN'
parameters regardless of version.

SQL syntax for prepared statements cannot be used in nested fashion.
That is, a statement passed to *Note `PREPARE': prepare. cannot itself
be a *Note `PREPARE': prepare, *Note `EXECUTE': execute, or *Note
`DEALLOCATE PREPARE': deallocate-prepare. statement.

SQL syntax for prepared statements is distinct from using prepared
statement API calls. For example, you cannot use the *Note
`mysql_stmt_prepare()': mysql-stmt-prepare. C API function to prepare a
*Note `PREPARE': prepare, *Note `EXECUTE': execute, or *Note
`DEALLOCATE PREPARE': deallocate-prepare. statement.

SQL syntax for prepared statements cannot be used within stored
routines (procedures or functions), or triggers. This restriction is
lifted as of MySQL 5.0.13 for stored procedures, but not for stored
functions or triggers. However, a cursor cannot be used for a dynamic
statement that is prepared and executed with *Note `PREPARE': prepare.
and *Note `EXECUTE': execute. The statement for a cursor is checked at
cursor creation time, so the statement cannot be dynamic.

SQL syntax for prepared statements does not support multi-statements
(that is, multiple statements within a single string separated by ``;''
characters).

To write C programs that use the *Note `CALL': call.  SQL statement to
execute stored procedures that contain prepared statements, the
`CLIENT_MULTI_RESULTS' flag must be enabled. This is because each *Note
`CALL': call.  returns a result to indicate the call status, in
addition to any result sets that might be returned by statements
executed within the procedure.

`CLIENT_MULTI_RESULTS' can be enabled when you call *Note
`mysql_real_connect()': mysql-real-connect, either explicitly by
passing the `CLIENT_MULTI_RESULTS' flag itself, or implicitly by passing
`CLIENT_MULTI_STATEMENTS' (which also enables `CLIENT_MULTI_RESULTS').
For additional information, see *Note call::.


File: manual.info,  Node: prepare,  Next: execute,  Prev: sql-syntax-prepared-statements,  Up: sql-syntax-prepared-statements

13.5.1 `PREPARE' Syntax
-----------------------

     PREPARE STMT_NAME FROM PREPARABLE_STMT

The *Note `PREPARE': prepare. statement prepares a statement and
assigns it a name, STMT_NAME, by which to refer to the statement later.
Statement names are not case sensitive.  PREPARABLE_STMT is either a
string literal or a user variable that contains the text of the
statement. The text must represent a single SQL statement, not multiple
statements. Within the statement, ``?'' characters can be used as
parameter markers to indicate where data values are to be bound to the
query later when you execute it. The ``?'' characters should not be
enclosed within quotation marks, even if you intend to bind them to
string values. Parameter markers can be used only where data values
should appear, not for SQL keywords, identifiers, and so forth.

If a prepared statement with the given name already exists, it is
deallocated implicitly before the new statement is prepared. This means
that if the new statement contains an error and cannot be prepared, an
error is returned and no statement with the given name exists.

A prepared statement is executed with *Note `EXECUTE': execute. and
released with *Note `DEALLOCATE PREPARE': deallocate-prepare.

The scope of a prepared statement is the session within which it is
created. Other sessions cannot see it.

For examples, see *Note sql-syntax-prepared-statements::.


File: manual.info,  Node: execute,  Next: deallocate-prepare,  Prev: prepare,  Up: sql-syntax-prepared-statements

13.5.2 `EXECUTE' Syntax
-----------------------

     EXECUTE STMT_NAME
         [USING @VAR_NAME [, @VAR_NAME] ...]

After preparing a statement with *Note `PREPARE': prepare, you execute
it with an *Note `EXECUTE': execute. statement that refers to the
prepared statement name. If the prepared statement contains any
parameter markers, you must supply a `USING' clause that lists user
variables containing the values to be bound to the parameters.
Parameter values can be supplied only by user variables, and the
`USING' clause must name exactly as many variables as the number of
parameter markers in the statement.

You can execute a given prepared statement multiple times, passing
different variables to it or setting the variables to different values
before each execution.

For examples, see *Note sql-syntax-prepared-statements::.


File: manual.info,  Node: deallocate-prepare,  Prev: execute,  Up: sql-syntax-prepared-statements

13.5.3 `DEALLOCATE PREPARE' Syntax
----------------------------------

     {DEALLOCATE | DROP} PREPARE STMT_NAME

To deallocate a prepared statement produced with *Note `PREPARE':
prepare, use a *Note `DEALLOCATE PREPARE': deallocate-prepare.
statement that refers to the prepared statement name. Attempting to
execute a prepared statement after deallocating it results in an error.

For examples, see *Note sql-syntax-prepared-statements::.


File: manual.info,  Node: sql-syntax-compound-statements,  Next: sql-syntax-server-administration,  Prev: sql-syntax-prepared-statements,  Up: sql-syntax

13.6 MySQL Compound-Statement Syntax
====================================

* Menu:

* begin-end::                    `BEGIN ... END' Compound-Statement Syntax
* statement-labels::             Statement Label Syntax
* declare::                      `DECLARE' Syntax
* stored-program-variables::     Variables in Stored Programs
* flow-control-statements::      Flow Control Statements
* cursors::                      Cursors
* condition-handling::           Condition Handling

This section describes the syntax for the *Note `BEGIN ... END':
begin-end.  compound statement and other statements that can be used in
the body of stored programs: Stored procedures and functions and
triggers.  These objects are defined in terms of SQL code that is
stored on the server for later invocation (see *Note
stored-programs-views::).

A compound statement is a block that can contain other blocks;
declarations for variables, condition handlers, and cursors; and flow
control constructs such as loops and conditional tests.


File: manual.info,  Node: begin-end,  Next: statement-labels,  Prev: sql-syntax-compound-statements,  Up: sql-syntax-compound-statements

13.6.1 `BEGIN ... END' Compound-Statement Syntax
------------------------------------------------

     [BEGIN_LABEL:] BEGIN
         [STATEMENT_LIST]
     END [END_LABEL]

*Note `BEGIN ... END': begin-end.  syntax is used for writing compound
statements, which can appear within stored programs (stored procedures
and functions, and triggers). A compound statement can contain multiple
statements, enclosed by the `BEGIN' and `END' keywords.  STATEMENT_LIST
represents a list of one or more statements, each terminated by a
semicolon (`;') statement delimiter. The STATEMENT_LIST itself is
optional, so the empty compound statement (`BEGIN END') is legal.

*Note `BEGIN ... END': begin-end.  blocks can be nested.

Use of multiple statements requires that a client is able to send
statement strings containing the `;' statement delimiter. In the *Note
`mysql': mysql. command-line client, this is handled with the
`delimiter' command.  Changing the `;' end-of-statement delimiter (for
example, to `//') permit `;' to be used in a program body. For an
example, see *Note stored-programs-defining::.

A *Note `BEGIN ... END': begin-end. block can be labeled. See *Note
statement-labels::.

The optional `[NOT] ATOMIC' clause is not supported. This means that no
transactional savepoint is set at the start of the instruction block
and the `BEGIN' clause used in this context has no effect on the
current transaction.

*Note*:

Within all stored programs, the parser treats *Note `BEGIN [WORK]':
commit.  as the beginning of a *Note `BEGIN ... END': begin-end. block.
To begin a transaction in this context, use *Note `START TRANSACTION':
commit. instead.


File: manual.info,  Node: statement-labels,  Next: declare,  Prev: begin-end,  Up: sql-syntax-compound-statements

13.6.2 Statement Label Syntax
-----------------------------

     [BEGIN_LABEL:] BEGIN
         [STATEMENT_LIST]
     END [END_LABEL]

     [BEGIN_LABEL:] LOOP
         STATEMENT_LIST
     END LOOP [END_LABEL]

     [BEGIN_LABEL:] REPEAT
         STATEMENT_LIST
     UNTIL SEARCH_CONDITION
     END REPEAT [END_LABEL]

     [BEGIN_LABEL:] WHILE SEARCH_CONDITION DO
         STATEMENT_LIST
     END WHILE [END_LABEL]

Labels are permitted for *Note `BEGIN ... END': begin-end.  blocks and
for the *Note `LOOP': loop-statement, *Note `REPEAT': repeat-statement,
and *Note `WHILE': while-statement.  statements. Label use for those
statements follows these rules:

   * BEGIN_LABEL must be followed by a colon.

   * BEGIN_LABEL can be given without END_LABEL. If END_LABEL is
     present, it must be the same as BEGIN_LABEL.

   * END_LABEL cannot be given without BEGIN_LABEL.

   * Labels at the same nesting level must be distinct.

   * Labels can be up to 16 characters long.

To refer to a label within the labeled construct, use an *Note
`ITERATE': iterate-statement.  or *Note `LEAVE': leave-statement.
statement. The following example uses those statements to continue
iterating or terminate the loop:

     CREATE PROCEDURE doiterate(p1 INT)
     BEGIN
       label1: LOOP
         SET p1 = p1 + 1;
         IF p1 < 10 THEN ITERATE label1; END IF;
         LEAVE label1;
       END LOOP label1;
     END;

The scope of a block label does not include the code for handlers
declared within the block. For details, see *Note declare-handler::.


File: manual.info,  Node: declare,  Next: stored-program-variables,  Prev: statement-labels,  Up: sql-syntax-compound-statements

13.6.3 `DECLARE' Syntax
-----------------------

The *Note `DECLARE': declare. statement is used to define various items
local to a program:

   * Local variables. See *Note stored-program-variables::.

   * Conditions and handlers. See *Note condition-handling::.

   * Cursors. See *Note cursors::.

*Note `DECLARE': declare. is permitted only inside a *Note `BEGIN ...
END': begin-end.  compound statement and must be at its start, before
any other statements.

Declarations must follow a certain order. Cursor declarations must
appear before handler declarations. Variable and condition declarations
must appear before cursor or handler declarations.


File: manual.info,  Node: stored-program-variables,  Next: flow-control-statements,  Prev: declare,  Up: sql-syntax-compound-statements

13.6.4 Variables in Stored Programs
-----------------------------------

* Menu:

* declare-local-variable::       Local Variable `DECLARE' Syntax
* local-variable-scope::         Local Variable Scope and Resolution

System variables and user-defined variables can be used in stored
programs, just as they can be used outside stored-program context.  In
addition, stored programs can use `DECLARE' to define local variables,
and stored routines (procedures and functions) can be declared to take
parameters that communicate values between the routine and its caller.

   * To declare local variables, use the *Note `DECLARE':
     declare-local-variable.  statement, as described in *Note
     declare-local-variable::.

   * Variables can be set directly with the *Note `SET': set-option.
     statement. See *Note set-option::.

   * Results from queries can be retrieved into local variables using
     *Note `SELECT ... INTO VAR_LIST': select-into. or by opening a
     cursor and using *Note `FETCH ... INTO VAR_LIST': fetch. See *Note
     select-into::, and *Note cursors::.

For information about the scope of local variables and how MySQL
resolves ambiguous names, see *Note local-variable-scope::.


File: manual.info,  Node: declare-local-variable,  Next: local-variable-scope,  Prev: stored-program-variables,  Up: stored-program-variables

13.6.4.1 Local Variable `DECLARE' Syntax
........................................

     DECLARE VAR_NAME [, VAR_NAME] ... TYPE [DEFAULT VALUE]

This statement declares local variables within stored programs.  To
provide a default value for a variable, include a `DEFAULT' clause. The
value can be specified as an expression; it need not be a constant. If
the `DEFAULT' clause is missing, the initial value is `NULL'.

Local variables are treated like stored routine parameters with respect
to data type and overflow checking. See *Note create-procedure::.

Variable declarations must appear before cursor or handler declarations.

Local variable names are not case sensitive. Permissible characters and
quoting rules are the same as for other identifiers, as described in
*Note identifiers::.

The scope of a local variable is the *Note `BEGIN ... END': begin-end.
block within which it is declared. The variable can be referred to in
blocks nested within the declaring block, except those blocks that
declare a variable with the same name.


File: manual.info,  Node: local-variable-scope,  Prev: declare-local-variable,  Up: stored-program-variables

13.6.4.2 Local Variable Scope and Resolution
............................................

The scope of a local variable is the *Note `BEGIN ... END': begin-end.
block within which it is declared. The variable can be referred to in
blocks nested within the declaring block, except those blocks that
declare a variable with the same name.

Local variables are in scope only during stored program execution.
References to them are not permitted within prepared statements because
those are global to the current session and the variables might have
gone out of scope when the statement is executed. For example, `SELECT
... INTO LOCAL_VAR' cannot be used as a prepared statement.

A local variable should not have the same name as a table column. If an
SQL statement, such as a *Note `SELECT ... INTO': select. statement,
contains a reference to a column and a declared local variable with the
same name, MySQL currently interprets the reference as the name of a
variable. Consider the following procedure definition:

     CREATE PROCEDURE sp1 (x VARCHAR(5))
     BEGIN
       DECLARE xname VARCHAR(5) DEFAULT 'bob';
       DECLARE newname VARCHAR(5);
       DECLARE xid INT;

       SELECT xname, id INTO newname, xid
         FROM table1 WHERE xname = xname;
       SELECT newname;
     END;

MySQL interprets `xname' in the *Note `SELECT': select. statement as a
reference to the `xname' _variable_ rather than the `xname' _column_.
Consequently, when the procedure `sp1()'is called, the `newname'
variable returns the value `'bob'' regardless of the value of the
`table1.xname' column.

Similarly, the cursor definition in the following procedure contains a
*Note `SELECT': select. statement that refers to `xname'. MySQL
interprets this as a reference to the variable of that name rather than
a column reference.

     CREATE PROCEDURE sp2 (x VARCHAR(5))
     BEGIN
       DECLARE xname VARCHAR(5) DEFAULT 'bob';
       DECLARE newname VARCHAR(5);
       DECLARE xid INT;
       DECLARE done TINYINT DEFAULT 0;
       DECLARE cur1 CURSOR FOR SELECT xname, id FROM table1;
       DECLARE CONTINUE HANDLER FOR NOT FOUND SET done = 1;

       OPEN cur1;
       read_loop: LOOP
         FETCH FROM cur1 INTO newname, xid;
         IF done THEN LEAVE read_loop; END IF;
         SELECT newname;
       END LOOP;
       CLOSE cur1;
     END;

See also *Note stored-program-restrictions::.


File: manual.info,  Node: flow-control-statements,  Next: cursors,  Prev: stored-program-variables,  Up: sql-syntax-compound-statements

13.6.5 Flow Control Statements
------------------------------

* Menu:

* case-statement::               `CASE' Syntax
* if-statement::                 `IF' Syntax
* iterate-statement::            `ITERATE' Syntax
* leave-statement::              `LEAVE' Syntax
* loop-statement::               `LOOP' Syntax
* repeat-statement::             `REPEAT' Syntax
* return::                       `RETURN' Syntax
* while-statement::              `WHILE' Syntax

MySQL supports the *Note `IF': if-statement, *Note `CASE':
case-statement, *Note `ITERATE': iterate-statement, *Note `LEAVE':
leave-statement.  *Note `LOOP': loop-statement, *Note `WHILE':
while-statement, and *Note `REPEAT': repeat-statement.  constructs for
flow control within stored programs. It also supports *Note `RETURN':
return. within stored functions.

Many of these constructs contain other statements, as indicated by the
grammar specifications in the following sections. Such constructs may
be nested. For example, an *Note `IF': if-statement.  statement might
contain a *Note `WHILE': while-statement.  loop, which itself contains a
*Note `CASE': case-statement.  statement.

MySQL does not support `FOR' loops.


File: manual.info,  Node: case-statement,  Next: if-statement,  Prev: flow-control-statements,  Up: flow-control-statements

13.6.5.1 `CASE' Syntax
......................

     CASE CASE_VALUE
         WHEN WHEN_VALUE THEN STATEMENT_LIST
         [WHEN WHEN_VALUE THEN STATEMENT_LIST] ...
         [ELSE STATEMENT_LIST]
     END CASE

Or:

     CASE
         WHEN SEARCH_CONDITION THEN STATEMENT_LIST
         [WHEN SEARCH_CONDITION THEN STATEMENT_LIST] ...
         [ELSE STATEMENT_LIST]
     END CASE

The *Note `CASE': case-statement.  statement for stored programs
implements a complex conditional construct.

*Note*:

There is also a `CASE' _expression_, which differs from the *Note
`CASE': case-statement.  _statement_ described here. See *Note
control-flow-functions::. The *Note `CASE': case-statement.  statement
cannot have an `ELSE NULL' clause, and it is terminated with `END CASE'
instead of `END'.

For the first syntax, CASE_VALUE is an expression. This value is
compared to the WHEN_VALUE expression in each `WHEN' clause until one
of them is equal. When an equal WHEN_VALUE is found, the corresponding
`THEN' clause STATEMENT_LIST executes. If no WHEN_VALUE is equal, the
`ELSE' clause STATEMENT_LIST executes, if there is one.

This syntax cannot be used to test for equality with `NULL' because
`NULL = NULL' is false. See *Note working-with-null::.

For the second syntax, each `WHEN' clause SEARCH_CONDITION expression is
evaluated until one is true, at which point its corresponding `THEN'
clause STATEMENT_LIST executes. If no SEARCH_CONDITION is equal, the
`ELSE' clause STATEMENT_LIST executes, if there is one.

If no WHEN_VALUE or SEARCH_CONDITION matches the value tested and the
*Note `CASE': case-statement.  statement contains no `ELSE' clause, a
`Case not found for CASE statement' error results.

Each STATEMENT_LIST consists of one or more SQL statements; an empty
STATEMENT_LIST is not permitted.

To handle situations where no value is matched by any `WHEN' clause,
use an `ELSE' containing an empty *Note `BEGIN ... END': begin-end.
block, as shown in this example. (The indentation used here in the
`ELSE' clause is for purposes of clarity only, and is not otherwise
significant.)

     DELIMITER |

     CREATE PROCEDURE p()
       BEGIN
         DECLARE v INT DEFAULT 1;

         CASE v
           WHEN 2 THEN SELECT v;
           WHEN 3 THEN SELECT 0;
           ELSE
             BEGIN
             END;
         END CASE;
       END;
       |


File: manual.info,  Node: if-statement,  Next: iterate-statement,  Prev: case-statement,  Up: flow-control-statements

13.6.5.2 `IF' Syntax
....................

     IF SEARCH_CONDITION THEN STATEMENT_LIST
         [ELSEIF SEARCH_CONDITION THEN STATEMENT_LIST] ...
         [ELSE STATEMENT_LIST]
     END IF

The *Note `IF': if-statement.  statement for stored programs implements
a basic conditional construct.

*Note*:

There is also an `IF()' _function_, which differs from the *Note `IF':
if-statement.  _statement_ described here. See *Note
control-flow-functions::. The *Note `IF': if-statement.  statement can
have `THEN', `ELSE', and `ELSEIF' clauses, and it is terminated with
`END IF'.

If the SEARCH_CONDITION evaluates to true, the corresponding `THEN' or
`ELSEIF' clause STATEMENT_LIST executes. If no SEARCH_CONDITION
matches, the `ELSE' clause STATEMENT_LIST executes.

Each STATEMENT_LIST consists of one or more SQL statements; an empty
STATEMENT_LIST is not permitted.

An `IF ... END IF' block, like all other flow-control blocks used
within stored programs, must be terminated with a semicolon, as shown
in this example:

     DELIMITER //

     CREATE FUNCTION SimpleCompare(n INT, m INT)
       RETURNS VARCHAR(20)

       BEGIN
         DECLARE s VARCHAR(20);

         IF n > m THEN SET s = '>';
         ELSEIF n = m THEN SET s = '=';
         ELSE SET s = '<';
         END IF;

         SET s = CONCAT(n, ' ', s, ' ', m);

         RETURN s;
       END //

     DELIMITER ;

As with other flow-control constructs, `IF ... END IF' blocks may be
nested within other flow-control constructs, including other *Note
`IF': if-statement.  statements. Each *Note `IF': if-statement. must be
terminated by its own `END IF' followed by a semicolon. You can use
indentation to make nested flow-control blocks more easily readable by
humans (although this is not required by MySQL), as shown here:

     DELIMITER //

     CREATE FUNCTION VerboseCompare (n INT, m INT)
       RETURNS VARCHAR(50)

       BEGIN
         DECLARE s VARCHAR(50);

         IF n = m THEN SET s = 'equals';
         ELSE
           IF n > m THEN SET s = 'greater';
           ELSE SET s = 'less';
           END IF;

           SET s = CONCAT('is ', s, ' than');
         END IF;

         SET s = CONCAT(n, ' ', s, ' ', m, '.');

         RETURN s;
       END //

     DELIMITER ;

In this example, the inner *Note `IF': if-statement. is evaluated only
if `n' is not equal to `m'.


File: manual.info,  Node: iterate-statement,  Next: leave-statement,  Prev: if-statement,  Up: flow-control-statements

13.6.5.3 `ITERATE' Syntax
.........................

     ITERATE LABEL

*Note `ITERATE': iterate-statement.  can appear only within *Note
`LOOP': loop-statement, *Note `REPEAT': repeat-statement, and *Note
`WHILE': while-statement.  statements.  *Note `ITERATE':
iterate-statement.  means `start the loop again.'

For an example, see *Note loop-statement::.


File: manual.info,  Node: leave-statement,  Next: loop-statement,  Prev: iterate-statement,  Up: flow-control-statements

13.6.5.4 `LEAVE' Syntax
.......................

     LEAVE LABEL

This statement is used to exit the flow control construct that has the
given label. If the label is for the outermost stored program block,
*Note `LEAVE': leave-statement.  exits the program.

*Note `LEAVE': leave-statement.  can be used within *Note `BEGIN ...
END': begin-end. or loop constructs (*Note `LOOP': loop-statement,
*Note `REPEAT': repeat-statement, *Note `WHILE': while-statement.).

For an example, see *Note loop-statement::.


File: manual.info,  Node: loop-statement,  Next: repeat-statement,  Prev: leave-statement,  Up: flow-control-statements

13.6.5.5 `LOOP' Syntax
......................

     [BEGIN_LABEL:] LOOP
         STATEMENT_LIST
     END LOOP [END_LABEL]

*Note `LOOP': loop-statement.  implements a simple loop construct,
enabling repeated execution of the statement list, which consists of
one or more statements, each terminated by a semicolon (`;') statement
delimiter. The statements within the loop are repeated until the loop
is terminated. Usually, this is accomplished with a *Note `LEAVE':
leave-statement.  statement. Within a stored function, *Note `RETURN':
return. can also be used, which exits the function entirely.

Neglecting to include a loop-termination statement results in an
infinite loop.

A *Note `LOOP': loop-statement.  statement can be labeled. For the
rules regarding label use, see *Note statement-labels::.

Example:

     CREATE PROCEDURE doiterate(p1 INT)
     BEGIN
       label1: LOOP
         SET p1 = p1 + 1;
         IF p1 < 10 THEN
           ITERATE label1;
         END IF;
         LEAVE label1;
       END LOOP label1;
       SET @x = p1;
     END;


File: manual.info,  Node: repeat-statement,  Next: return,  Prev: loop-statement,  Up: flow-control-statements

13.6.5.6 `REPEAT' Syntax
........................

     [BEGIN_LABEL:] REPEAT
         STATEMENT_LIST
     UNTIL SEARCH_CONDITION
     END REPEAT [END_LABEL]

The statement list within a *Note `REPEAT': repeat-statement.
statement is repeated until the SEARCH_CONDITION expression is true.
Thus, a *Note `REPEAT': repeat-statement.  always enters the loop at
least once.  STATEMENT_LIST consists of one or more statements, each
terminated by a semicolon (`;') statement delimiter.

A *Note `REPEAT': repeat-statement.  statement can be labeled. For the
rules regarding label use, see *Note statement-labels::.

Example:

     mysql> delimiter //

     mysql> CREATE PROCEDURE dorepeat(p1 INT)
         -> BEGIN
         ->   SET @x = 0;
         ->   REPEAT
         ->     SET @x = @x + 1;
         ->   UNTIL @x > p1 END REPEAT;
         -> END
         -> //
     Query OK, 0 rows affected (0.00 sec)

     mysql> CALL dorepeat(1000)//
     Query OK, 0 rows affected (0.00 sec)

     mysql> SELECT @x//
     +------+
     | @x   |
     +------+
     | 1001 |
     +------+
     1 row in set (0.00 sec)


File: manual.info,  Node: return,  Next: while-statement,  Prev: repeat-statement,  Up: flow-control-statements

13.6.5.7 `RETURN' Syntax
........................

     RETURN EXPR

The *Note `RETURN': return. statement terminates execution of a stored
function and returns the value EXPR to the function caller. There must
be at least one *Note `RETURN': return.  statement in a stored
function. There may be more than one if the function has multiple exit
points.

This statement is not used in stored procedures or triggers. The *Note
`LEAVE': leave-statement.  statement can be used to exit a stored
program of those types.


File: manual.info,  Node: while-statement,  Prev: return,  Up: flow-control-statements

13.6.5.8 `WHILE' Syntax
.......................

     [BEGIN_LABEL:] WHILE SEARCH_CONDITION DO
         STATEMENT_LIST
     END WHILE [END_LABEL]

The statement list within a *Note `WHILE': while-statement.  statement
is repeated as long as the SEARCH_CONDITION expression is true.
STATEMENT_LIST consists of one or more SQL statements, each terminated
by a semicolon (`;') statement delimiter.

A *Note `WHILE': while-statement.  statement can be labeled. For the
rules regarding label use, see *Note statement-labels::.

Example:

     CREATE PROCEDURE dowhile()
     BEGIN
       DECLARE v1 INT DEFAULT 5;

       WHILE v1 > 0 DO
         ...
         SET v1 = v1 - 1;
       END WHILE;
     END;


File: manual.info,  Node: cursors,  Next: condition-handling,  Prev: flow-control-statements,  Up: sql-syntax-compound-statements

13.6.6 Cursors
--------------

* Menu:

* close::                        Cursor `CLOSE' Syntax
* declare-cursor::               Cursor `DECLARE' Syntax
* fetch::                        Cursor `FETCH' Syntax
* open::                         Cursor `OPEN' Syntax

MySQL supports cursors inside stored programs. The syntax is as in
embedded SQL. Cursors have these properties:

   * Asensitive: The server may or may not make a copy of its result
     table

   * Read only: Not updatable

   * Nonscrollable: Can be traversed only in one direction and cannot
     skip rows

Cursor declarations must appear before handler declarations and after
variable and condition declarations.

Example:

     CREATE PROCEDURE curdemo()
     BEGIN
       DECLARE done INT DEFAULT FALSE;
       DECLARE a CHAR(16);
       DECLARE b, c INT;
       DECLARE cur1 CURSOR FOR SELECT id,data FROM test.t1;
       DECLARE cur2 CURSOR FOR SELECT i FROM test.t2;
       DECLARE CONTINUE HANDLER FOR NOT FOUND SET done = TRUE;

       OPEN cur1;
       OPEN cur2;

       read_loop: LOOP
         FETCH cur1 INTO a, b;
         FETCH cur2 INTO c;
         IF done THEN
           LEAVE read_loop;
         END IF;
         IF b < c THEN
           INSERT INTO test.t3 VALUES (a,b);
         ELSE
           INSERT INTO test.t3 VALUES (a,c);
         END IF;
       END LOOP;

       CLOSE cur1;
       CLOSE cur2;
     END;


File: manual.info,  Node: close,  Next: declare-cursor,  Prev: cursors,  Up: cursors

13.6.6.1 Cursor `CLOSE' Syntax
..............................

     CLOSE CURSOR_NAME

This statement closes a previously opened cursor. For an example, see
*Note cursors::.

An error occurs if the cursor is not open.

If not closed explicitly, a cursor is closed at the end of the *Note
`BEGIN ... END': begin-end. block in which it was declared.


File: manual.info,  Node: declare-cursor,  Next: fetch,  Prev: close,  Up: cursors

13.6.6.2 Cursor `DECLARE' Syntax
................................

     DECLARE CURSOR_NAME CURSOR FOR SELECT_STATEMENT

This statement declares a cursor and associates it with a *Note
`SELECT': select. statement that retrieves the rows to be traversed by
the cursor. To fetch the rows later, use a *Note `FETCH': fetch.
statement. The number of columns retrieved by the *Note `SELECT':
select. statement must match the number of output variables specified
in the *Note `FETCH': fetch. statement.

The *Note `SELECT': select. statement cannot have an `INTO' clause.

Cursor declarations must appear before handler declarations and after
variable and condition declarations.

A stored program may contain multiple cursor declarations, but each
cursor declared in a given block must have a unique name.  For an
example, see *Note cursors::.

For information available through *Note `SHOW': show. statements, it is
possible in many cases to obtain equivalent information by using a
cursor with an `INFORMATION_SCHEMA' table.


File: manual.info,  Node: fetch,  Next: open,  Prev: declare-cursor,  Up: cursors

13.6.6.3 Cursor `FETCH' Syntax
..............................

     FETCH CURSOR_NAME INTO VAR_NAME [, VAR_NAME] ...

This statement fetches the next row for the *Note `SELECT': select.
statement associated with the specified cursor (which must be open),
and advances the cursor pointer. If a row exists, the fetched columns
are stored in the named variables. The number of columns retrieved by
the *Note `SELECT': select. statement must match the number of output
variables specified in the *Note `FETCH': fetch. statement.

If no more rows are available, a No Data condition occurs with SQLSTATE
value `'02000''. To detect this condition, you can set up a handler for
it (or for a `NOT FOUND' condition). For an example, see *Note
cursors::.


File: manual.info,  Node: open,  Prev: fetch,  Up: cursors

13.6.6.4 Cursor `OPEN' Syntax
.............................

     OPEN CURSOR_NAME

This statement opens a previously declared cursor. For an example, see
*Note cursors::.


File: manual.info,  Node: condition-handling,  Prev: cursors,  Up: sql-syntax-compound-statements

13.6.7 Condition Handling
-------------------------

* Menu:

* declare-condition::            `DECLARE ... CONDITION' Syntax
* declare-handler::              `DECLARE ... HANDLER' Syntax

Conditions may arise during stored program execution that require
special handling, such as exiting the current program block or
continuing execution. Handlers can be defined for general conditions
such as warnings or exceptions, or for specific conditions such as a
particular error code. Specific conditions can be assigned names and
referred to that way in handlers.

To name a condition, use the *Note `DECLARE ... CONDITION':
declare-condition. statement. To declare a handler, use the *Note
`DECLARE ... HANDLER': declare-handler. statement. See *Note
declare-condition::, and *Note declare-handler::.

Other statements related to conditions are `SIGNAL', `RESIGNAL', and
`GET DIAGNOSTICS'. The `SIGNAL' and `RESIGNAL' statements are not
supported until MySQL 5.5. The `GET DIAGNOSTICS' statement is not
supported until MySQL 5.6.


File: manual.info,  Node: declare-condition,  Next: declare-handler,  Prev: condition-handling,  Up: condition-handling

13.6.7.1 `DECLARE ... CONDITION' Syntax
.......................................

     DECLARE CONDITION_NAME CONDITION FOR CONDITION_VALUE

     CONDITION_VALUE:
         MYSQL_ERROR_CODE
       | SQLSTATE [VALUE] SQLSTATE_VALUE

The *Note `DECLARE ... CONDITION': declare-condition. statement
declares a named error condition, associating a name with a condition
that needs specific handling. The name can be referred to in a
subsequent *Note `DECLARE ... HANDLER': declare-handler. statement (see
*Note declare-handler::).

Condition declarations must appear before cursor or handler
declarations.

The CONDITION_VALUE for *Note `DECLARE ... CONDITION':
declare-condition. can be a MySQL error code (a number) or an SQLSTATE
value (a 5-character string literal). You should not use MySQL error
code 0 or SQLSTATE values that begin with `'00'', because those
indicate success rather than an error condition. For a list of MySQL
error codes and SQLSTATE values, see *Note error-messages-server::.

Using names for conditions can help make stored program code clearer.
For example, this handler applies to attempts to drop a nonexistent
table, but that is apparent only if you know the meaning of MySQL error
code 1051:

     DECLARE CONTINUE HANDLER FOR 1051
       BEGIN
         -- body of handler
       END;

By declaring a name for the condition, the purpose of the handler is
more readily seen:

     DECLARE no_such_table CONDITION FOR 1051;
     DECLARE CONTINUE HANDLER FOR no_such_table
       BEGIN
         -- body of handler
       END;

Here is a named condition for the same condition, but based on the
corresponding SQLSTATE value rather than the MySQL error code:

     DECLARE no_such_table CONDITION FOR SQLSTATE '42S02';
     DECLARE CONTINUE HANDLER FOR no_such_table
       BEGIN
         -- body of handler
       END;


File: manual.info,  Node: declare-handler,  Prev: declare-condition,  Up: condition-handling

13.6.7.2 `DECLARE ... HANDLER' Syntax
.....................................

     DECLARE HANDLER_ACTION HANDLER
         FOR CONDITION_VALUE [, CONDITION_VALUE] ...
         STATEMENT

     HANDLER_ACTION:
         CONTINUE
       | EXIT
       | UNDO

     CONDITION_VALUE:
         MYSQL_ERROR_CODE
       | SQLSTATE [VALUE] SQLSTATE_VALUE
       | CONDITION_NAME
       | SQLWARNING
       | NOT FOUND
       | SQLEXCEPTION

The *Note `DECLARE ... HANDLER': declare-handler. statement specifies a
handler that may deal with one or more conditions. If one of these
conditions occurs, the specified STATEMENT executes.  STATEMENT can be
a simple statement such as `SET VAR_NAME = VALUE', or a compound
statement written using `BEGIN' and `END' (see *Note begin-end::).

Handler declarations must appear after variable or condition
declarations.

The HANDLER_ACTION value indicates what action the handler takes after
execution of the handler statement:

   * `CONTINUE': Execution of the current program continues.

   * `EXIT': Execution terminates for the *Note `BEGIN ... END':
     begin-end. compound statement in which the handler is declared.
     This is true even if the condition occurs in an inner block.

   * `UNDO': Not supported.

The CONDITION_VALUE for *Note `DECLARE ... HANDLER': declare-handler.
indicates the specific condition or class of conditions that activates
the handler:

   * A MySQL error code (a number) or an SQLSTATE value (a 5-character
     string literal). You should not use MySQL error code 0 or SQLSTATE
     values that begin with `'00'', because those indicate success
     rather than an error condition. For a list of MySQL error codes
     and SQLSTATE values, see *Note error-messages-server::.

   * A condition name previously specified with *Note `DECLARE ...
     CONDITION': declare-condition. A condition name can be associated
     with a MySQL error code or SQLSTATE value. See *Note
     declare-condition::.

   * `SQLWARNING' is shorthand for the class of SQLSTATE values that
     begin with `'01''.

   * `NOT FOUND' is shorthand for the class of SQLSTATE values that
     begin with `'02''.  This is relevant within the context of cursors
     and is used to control what happens when a cursor reaches the end
     of a data set. If no more rows are available, a No Data condition
     occurs with SQLSTATE value `'02000''. To detect this condition,
     you can set up a handler for it (or for a `NOT FOUND' condition).
     For an example, see *Note cursors::. This condition also occurs
     for `SELECT ... INTO VAR_LIST' statements that retrieve no rows.

   * `SQLEXCEPTION' is shorthand for the class of SQLSTATE values that
     do not begin with `'00'', `'01'', or `'02''.

If a condition occurs for which no handler has been declared, the
action taken depends on the class of the condition:

   * For `SQLEXCEPTION' conditions, the stored program terminates at
     the statement that raised the condition, as if there were an `EXIT'
     handler. If the program was called by another stored program, the
     caller handles the condition using the handler selection rules
     applied to its own handlers.

   * For `SQLWARNING' or `NOT FOUND' conditions, the program continues
     executing, as if there were a `CONTINUE' handler.

The following example associates a handler with SQLSTATE value
`'23000'', which occurs for a duplicate-key error:

     mysql> CREATE TABLE test.t (s1 INT, PRIMARY KEY (s1));
     Query OK, 0 rows affected (0.00 sec)

     mysql> delimiter //

     mysql> CREATE PROCEDURE handlerdemo ()
         -> BEGIN
         ->   DECLARE CONTINUE HANDLER FOR SQLSTATE '23000' SET @x2 = 1;
         ->   SET @x = 1;
         ->   INSERT INTO test.t VALUES (1);
         ->   SET @x = 2;
         ->   INSERT INTO test.t VALUES (1);
         ->   SET @x = 3;
         -> END;
         -> //
     Query OK, 0 rows affected (0.00 sec)

     mysql> CALL handlerdemo()//
     Query OK, 0 rows affected (0.00 sec)

     mysql> SELECT @x//
         +------+
         | @x   |
         +------+
         | 3    |
         +------+
         1 row in set (0.00 sec)

Notice that `@x' is `3' after the procedure executes, which shows that
execution continued to the end of the procedure after the error
occurred. If the *Note `DECLARE ... HANDLER': declare-handler.
statement had not been present, MySQL would have taken the default
action (`EXIT') after the second *Note `INSERT': insert. failed due to
the `PRIMARY KEY' constraint, and `SELECT @x' would have returned `2'.

To ignore a condition, declare a `CONTINUE' handler for it and
associate it with an empty block. For example:

     DECLARE CONTINUE HANDLER FOR SQLWARNING BEGIN END;

The scope of a block label does not include the code for handlers
declared within the block. Therefore, the statement associated with a
handler cannot use *Note `ITERATE': iterate-statement.  or *Note
`LEAVE': leave-statement.  to refer to labels for blocks that enclose
the handler declaration. Consider the following example, where the
*Note `REPEAT': repeat-statement.  block has a label of `retry':

     CREATE PROCEDURE p ()
     BEGIN
       DECLARE i INT DEFAULT 3;
       retry:
         REPEAT
           BEGIN
             DECLARE CONTINUE HANDLER FOR SQLWARNING
               BEGIN
                 ITERATE retry;  # illegal
               END;
             IF i < 0 THEN
               LEAVE retry;        # legal
             END IF;
             SET i = i - 1;
           END;
         UNTIL FALSE END REPEAT;
     END;

The `retry' label is in scope for the *Note `IF': if-statement.
statement within the block. It is not in scope for the `CONTINUE'
handler, so the reference there is invalid and results in an error:

     ERROR 1308 (42000): LEAVE with no matching label: retry

To avoid references to outer labels in handlers, use one of these
strategies:

   * To leave the block, use an `EXIT' handler.  If no block cleanup is
     required, the *Note `BEGIN ... END': begin-end. handler body can
     be empty:

          DECLARE EXIT HANDLER FOR SQLWARNING BEGIN END;

     Otherwise, put the cleanup statements in the handler body:

          DECLARE EXIT HANDLER FOR SQLWARNING
            BEGIN
              BLOCK CLEANUP STATEMENTS
            END;

   * To continue execution, set a status variable in a `CONTINUE'
     handler that can be checked in the enclosing block to determine
     whether the handler was invoked. The following example uses the
     variable `done' for this purpose:

          CREATE PROCEDURE p ()
          BEGIN
            DECLARE i INT DEFAULT 3;
            DECLARE done INT DEFAULT FALSE;
            retry:
              REPEAT
                BEGIN
                  DECLARE CONTINUE HANDLER FOR SQLWARNING
                    BEGIN
                      SET done = TRUE;
                    END;
                  IF done OR i < 0 THEN
                    LEAVE retry;
                  END IF;
                  SET i = i - 1;
                END;
              UNTIL FALSE END REPEAT;
          END;


File: manual.info,  Node: sql-syntax-server-administration,  Next: sql-syntax-utility,  Prev: sql-syntax-compound-statements,  Up: sql-syntax

13.7 Database Administration Statements
=======================================

* Menu:

* account-management-sql::       Account Management Statements
* table-maintenance-sql::        Table Maintenance Statements
* plugin-sql::                   User-Defined Function Statements
* set-option::                   `SET' Syntax
* show::                         `SHOW' Syntax
* other-administrative-sql::     Other Administrative Statements


File: manual.info,  Node: account-management-sql,  Next: table-maintenance-sql,  Prev: sql-syntax-server-administration,  Up: sql-syntax-server-administration

13.7.1 Account Management Statements
------------------------------------

* Menu:

* create-user::                  `CREATE USER' Syntax
* drop-user::                    `DROP USER' Syntax
* grant::                        `GRANT' Syntax
* rename-user::                  `RENAME USER' Syntax
* revoke::                       `REVOKE' Syntax
* set-password::                 `SET PASSWORD' Syntax

MySQL account information is stored in the tables of the `mysql'
database. This database and the access control system are discussed
extensively in *Note server-administration::, which you should consult
for additional details.

*Important*:

Some releases of MySQL introduce changes to the structure of the grant
tables to add new privileges or features. Whenever you update to a new
version of MySQL, you should update your grant tables to make sure that
they have the current structure so that you can take advantage of any
new capabilities. See *Note mysql-upgrade::.


File: manual.info,  Node: create-user,  Next: drop-user,  Prev: account-management-sql,  Up: account-management-sql

13.7.1.1 `CREATE USER' Syntax
.............................

     CREATE USER USER_SPECIFICATION
         [, USER_SPECIFICATION] ...

     USER_SPECIFICATION:
         USER [IDENTIFIED BY [PASSWORD] 'PASSWORD']

The *Note `CREATE USER': create-user. statement creates new MySQL
accounts. To use it, you must have the global `CREATE USER' privilege
or the `INSERT' privilege for the `mysql' database. For each account,
*Note `CREATE USER': create-user. creates a new row in the `mysql.user'
table and assigns the account no privileges. An error occurs if the
account already exists.

Each account name uses the format described in *Note account-names::.
For example:

     CREATE USER 'jeffrey'@'localhost' IDENTIFIED BY 'mypass';

If you specify only the user name part of the account name, a host name
part of `'%'' is used.

The user specification may indicate how the user should authenticate
when connecting to the server:

   * To enable the user to connect with no password (which is
     _insecure_), include no `IDENTIFIED BY' clause:

          CREATE USER 'jeffrey'@'localhost';

   * To assign a password, use `IDENTIFIED BY' with the literal
     plaintext password value:

          CREATE USER 'jeffrey'@'localhost' IDENTIFIED BY 'mypass';

   * To avoid specifying the plaintext password if you know its hash
     value (the value that `PASSWORD()' would return for the password),
     specify the hash value preceded by the keyword `PASSWORD':

          CREATE USER 'jeffrey'@'localhost'
          IDENTIFIED BY PASSWORD '*90E462C37378CED12064BB3388827D2BA3A9B689';

For additional information about setting passwords, see *Note
assigning-passwords::.

*Important*:

*Note `CREATE USER': create-user. may be recorded in server logs or in
a history file such as `~/.mysql_history', which means that plaintext
passwords may be read by anyone having read access to that information.
See *Note password-security::.

*Important*:

Some releases of MySQL introduce changes to the structure of the grant
tables to add new privileges or features. Whenever you update to a new
version of MySQL, you should update your grant tables to make sure that
they have the current structure so that you can take advantage of any
new capabilities. See *Note mysql-upgrade::.

The *Note `CREATE USER': create-user. statement was added in MySQL
5.0.2.


File: manual.info,  Node: drop-user,  Next: grant,  Prev: create-user,  Up: account-management-sql

13.7.1.2 `DROP USER' Syntax
...........................

     DROP USER USER [, USER] ...

The *Note `DROP USER': drop-user. statement removes one or more MySQL
accounts. To use it, you must have the global `CREATE USER' privilege
or the `DELETE' privilege for the `mysql' database. Each account name
uses the format described in *Note account-names::. For example:

     DROP USER 'jeffrey'@'localhost';

If you specify only the user name part of the account name, a host name
part of `'%'' is used.

*Note `DROP USER': drop-user. as present in MySQL 5.0.0 removes only
accounts that have no privileges. In MySQL 5.0.2, it was modified to
remove account privileges as well.  This means that the procedure for
removing an account depends on your version of MySQL.

As of MySQL 5.0.2, you can remove an account and its privileges as
follows:

     DROP USER USER;

The statement removes privilege rows for the account from all grant
tables.

Before MySQL 5.0.2, *Note `DROP USER': drop-user.  serves only to
remove account rows from the `user' table for accounts that have no
privileges. To remove a MySQL account completely (including all of its
privileges), you should use the following procedure, performing these
steps in the order shown:

  1. Use *Note `SHOW GRANTS': show-grants. to determine what privileges
     the account has. See *Note show-grants::.

  2. Use *Note `REVOKE': revoke. to revoke the privileges displayed by
     *Note `SHOW GRANTS': show-grants. This removes rows for the
     account from all the grant tables except the `user' table, and
     revokes any global privileges listed in the `user' table. See
     *Note grant::.

  3. Delete the account by using *Note `DROP USER': drop-user. to
     remove the `user' table row.

*Important*:

*Note `DROP USER': drop-user. does not automatically close any open
user sessions. Rather, in the event that a user with an open session is
dropped, the statement does not take effect until that user's session is
closed. Once the session is closed, the user is dropped, and that
user's next attempt to log in will fail. _This is by design_.

*Note `DROP USER': drop-user. does not automatically drop or invalidate
databases or objects within them that the old user created. This
includes stored programs or views for which the `DEFINER' attribute
names the dropped user.  Attempts to access such objects may produce an
error if they execute in definer security context. (For information
about security context, see *Note stored-programs-security::.)


File: manual.info,  Node: grant,  Next: rename-user,  Prev: drop-user,  Up: account-management-sql

13.7.1.3 `GRANT' Syntax
.......................

     GRANT
         PRIV_TYPE [(COLUMN_LIST)]
           [, PRIV_TYPE [(COLUMN_LIST)]] ...
         ON [OBJECT_TYPE] PRIV_LEVEL
         TO USER_SPECIFICATION [, USER_SPECIFICATION] ...
         [REQUIRE {NONE | SSL_OPTION [[AND] SSL_OPTION] ...}]
         [WITH WITH_OPTION ...]

     OBJECT_TYPE:
         TABLE
       | FUNCTION
       | PROCEDURE

     PRIV_LEVEL:
         *
       | *.*
       | DB_NAME.*
       | DB_NAME.TBL_NAME
       | TBL_NAME
       | DB_NAME.ROUTINE_NAME

     USER_SPECIFICATION:
         USER [IDENTIFIED BY [PASSWORD] 'PASSWORD']

     SSL_OPTION:
         SSL
       | X509
       | CIPHER 'CIPHER'
       | ISSUER 'ISSUER'
       | SUBJECT 'SUBJECT'

     WITH_OPTION:
         GRANT OPTION
       | MAX_QUERIES_PER_HOUR COUNT
       | MAX_UPDATES_PER_HOUR COUNT
       | MAX_CONNECTIONS_PER_HOUR COUNT
       | MAX_USER_CONNECTIONS COUNT

The *Note `GRANT': grant. statement grants privileges to MySQL user
accounts.  *Note `GRANT': grant. also serves to specify other account
characteristics such as use of secure connections and limits on access
to server resources. To use *Note `GRANT': grant, you must have the
`GRANT OPTION' privilege, and you must have the privileges that you are
granting.

Normally, a database administrator first uses *Note `CREATE USER':
create-user. to create an account, then *Note `GRANT': grant. to define
its privileges and characteristics. For example:

     CREATE USER 'jeffrey'@'localhost' IDENTIFIED BY 'mypass';
     GRANT ALL ON db1.* TO 'jeffrey'@'localhost';
     GRANT SELECT ON db2.invoice TO 'jeffrey'@'localhost';
     GRANT USAGE ON *.* TO 'jeffrey'@'localhost' WITH MAX_QUERIES_PER_HOUR 90;

However, if an account named in a *Note `GRANT': grant. statement does
not already exist, *Note `GRANT': grant. may create it under the
conditions described later in the discussion of the
`NO_AUTO_CREATE_USER' SQL mode.

The *Note `REVOKE': revoke. statement is related to *Note `GRANT':
grant. and enables administrators to remove account privileges. See
*Note revoke::.

To determine what privileges an account has, use *Note `SHOW GRANTS':
show-grants. See *Note show-grants::.

There are several aspects to the `GRANT' statement, described under the
following topics in this section:

   * Privileges Supported by MySQL

   * Global Privileges

   * Database Privileges

   * Table Privileges

   * Column Privileges

   * Stored Routine Privileges

   * Account Names and Passwords

   * Other Account Characteristics

   * MySQL and Standard SQL Versions of *Note `GRANT': grant.

*Important*:

Some releases of MySQL introduce changes to the structure of the grant
tables to add new privileges or features. Whenever you update to a new
version of MySQL, you should update your grant tables to make sure that
they have the current structure so that you can take advantage of any
new capabilities. See *Note mysql-upgrade::.

* Privileges Supported by MySQL *

The following table summarizes the permissible PRIV_TYPE privilege
types that can be specified for the *Note `GRANT': grant. and *Note
`REVOKE': revoke. statements. For additional information about these
privileges, see *Note privileges-provided::.

*Permissible Privileges for `GRANT' and `REVOKE'*

Privilege              Meaning
`ALL [PRIVILEGES]'     Grant all privileges at specified access level
                       except `GRANT OPTION'
`ALTER'                Enable use of *Note `ALTER TABLE': alter-table.
`ALTER ROUTINE'        Enable stored routines to be altered or dropped
`CREATE'               Enable database and table creation
`CREATE ROUTINE'       Enable stored routine creation
`CREATE TEMPORARY      Enable use of *Note `CREATE TEMPORARY TABLE':
TABLES'                create-table.
`CREATE USER'          Enable use of *Note `CREATE USER': create-user,
                       *Note `DROP USER': drop-user, *Note `RENAME
                       USER': rename-user, and *Note `REVOKE ALL
                       PRIVILEGES': revoke.
`CREATE VIEW'          Enable views to be created or altered
`DELETE'               Enable use of *Note `DELETE': delete.
`DROP'                 Enable databases, tables, and views to be dropped
`EXECUTE'              Enable the user to execute stored routines
`FILE'                 Enable the user to cause the server to read or
                       write files
`GRANT OPTION'         Enable privileges to be granted to or removed
                       from other accounts
`INDEX'                Enable indexes to be created or dropped
`INSERT'               Enable use of *Note `INSERT': insert.
`LOCK TABLES'          Enable use of *Note `LOCK TABLES': lock-tables.
                       on tables for which you have the *Note `SELECT':
                       select.  privilege
`PROCESS'              Enable the user to see all processes with *Note
                       `SHOW PROCESSLIST': show-processlist.
`REFERENCES'           Not implemented
`RELOAD'               Enable use of *Note `FLUSH': flush. operations
`REPLICATION CLIENT'   Enable the user to ask where master or slave
                       servers are
`REPLICATION SLAVE'    Enable replication slaves to read binary log
                       events from the master
`SELECT'               Enable use of *Note `SELECT': select.
`SHOW DATABASES'       Enable *Note `SHOW DATABASES': show-databases. to
                       show all databases
`SHOW VIEW'            Enable use of *Note `SHOW CREATE VIEW':
                       show-create-view.
`SHUTDOWN'             Enable use of *Note `mysqladmin shutdown':
                       mysqladmin.
`SUPER'                Enable use of other administrative operations
                       such as *Note `CHANGE MASTER TO':
                       change-master-to, *Note `KILL': kill, *Note
                       `PURGE BINARY LOGS': purge-binary-logs, *Note
                       `SET GLOBAL': set-option, and *Note `mysqladmin
                       debug': mysqladmin. command
`UPDATE'               Enable use of *Note `UPDATE': update.
`USAGE'                Synonym for `no privileges'

The `EXECUTE' privilege is not operational until MySQL 5.0.3. `CREATE
VIEW' and `SHOW VIEW' were added in MySQL 5.0.1. `CREATE USER', `CREATE
ROUTINE', and `ALTER ROUTINE' were added in MySQL 5.0.3.

In *Note `GRANT': grant. statements, the `ALL [PRIVILEGES]' privilege
is named by itself and cannot be specified along with other privileges.
It stands for all privileges available for the level at which
privileges are to be granted except for the `GRANT OPTION' privilege.

`USAGE' can be specified to create a user that has no privileges, or to
specify the `REQUIRE' or `WITH' clauses for an account without changing
its existing privileges.

MySQL account information is stored in the tables of the `mysql'
database. This database and the access control system are discussed
extensively in *Note privilege-system::, which you should consult for
additional details.

If the grant tables hold privilege rows that contain mixed-case
database or table names and the `lower_case_table_names' system
variable is set to a nonzero value, *Note `REVOKE': revoke. cannot be
used to revoke these privileges. It will be necessary to manipulate the
grant tables directly. (*Note `GRANT': grant. will not create such rows
when `lower_case_table_names' is set, but such rows might have been
created prior to setting that variable.)

Privileges can be granted at several levels, depending on the syntax
used for the `ON' clause. For *Note `REVOKE': revoke, the same `ON'
syntax specifies which privileges to take away. The examples shown here
include no `IDENTIFIED BY 'PASSWORD'' clause for brevity, but you
should include one if the account does not already exist, to avoid
creating an insecure account that has no password.

* Global Privileges *

Global privileges are administrative or apply to all databases on a
given server. To assign global privileges, use `ON *.*' syntax:

     GRANT ALL ON *.* TO 'someuser'@'somehost';
     GRANT SELECT, INSERT ON *.* TO 'someuser'@'somehost';

Before MySQL 5.0.23, privileges also are assigned at the global level
if you use `ON *' syntax and you have _not_ selected a default
database. As of 5.0.23, `ON *' requires a default database and produces
an error if there is none.

The `CREATE USER', `FILE', `PROCESS', `RELOAD', `REPLICATION CLIENT',
`REPLICATION SLAVE', `SHOW DATABASES', `SHUTDOWN', and `SUPER'
privileges are administrative and can only be granted globally.

Other privileges can be granted globally or at more specific levels.

MySQL stores global privileges in the `mysql.user' table.

* Database Privileges *

Database privileges apply to all objects in a given database. To assign
database-level privileges, use `ON DB_NAME.*' syntax:

     GRANT ALL ON mydb.* TO 'someuser'@'somehost';
     GRANT SELECT, INSERT ON mydb.* TO 'someuser'@'somehost';

If you use `ON *' syntax (rather than `ON *.*' and you have selected a
default database, privileges are assigned at the database level for the
default database. An error occurs if there is no default database.

The `CREATE', `DROP', `GRANT OPTION', and `LOCK TABLES' privileges can
be specified at the database level. Table or routine privileges also
can be specified at the database level, in which case they apply to all
tables or routines in the database.

MySQL stores database privileges in the `mysql.db' table.

* Table Privileges *

Table privileges apply to all columns in a given table. To assign
table-level privileges, use `ON DB_NAME.TBL_NAME' syntax:

     GRANT ALL ON mydb.mytbl TO 'someuser'@'somehost';
     GRANT SELECT, INSERT ON mydb.mytbl TO 'someuser'@'somehost';

If you specify TBL_NAME rather than DB_NAME.TBL_NAME, the statement
applies to TBL_NAME in the default database. An error occurs if there
is no default database.

The permissible PRIV_TYPE values at the table level are `ALTER',
`CREATE VIEW', `CREATE', `DELETE', `DROP', `GRANT OPTION', `INDEX',
`INSERT', `SELECT', `SHOW VIEW', and `UPDATE'.

MySQL stores table privileges in the `mysql.tables_priv' table.

* Column Privileges *

Column privileges apply to single columns in a given table. Each
privilege to be granted at the column level must be followed by the
column or columns, enclosed within parentheses.

     GRANT SELECT (col1), INSERT (col1,col2) ON mydb.mytbl TO 'someuser'@'somehost';

The permissible PRIV_TYPE values for a column (that is, when you use a
COLUMN_LIST clause) are `INSERT', `SELECT', and `UPDATE'.

MySQL stores column privileges in the `mysql.columns_priv' table.

* Stored Routine Privileges *

The `ALTER ROUTINE', `CREATE ROUTINE', `EXECUTE', and `GRANT OPTION'
privileges apply to stored routines (procedures and functions). They
can be granted at the global and database levels. Except for `CREATE
ROUTINE', these privileges can be granted at the routine level for
individual routines.

     GRANT CREATE ROUTINE ON mydb.* TO 'someuser'@'somehost';
     GRANT EXECUTE ON PROCEDURE mydb.myproc TO 'someuser'@'somehost';

The permissible PRIV_TYPE values at the routine level are `ALTER
ROUTINE', `EXECUTE', and `GRANT OPTION'.  `CREATE ROUTINE' is not a
routine-level privilege because you must have this privilege to create
a routine in the first place.

MySQL stores routine-level privileges in the `mysql.procs_priv' table.

For the global, database, table, and routine levels, *Note `GRANT ALL':
grant.  assigns only the privileges that exist at the level you are
granting. For example, `GRANT ALL ON DB_NAME.*' is a database-level
statement, so it does not grant any global-only privileges such as
`FILE'.

The OBJECT_TYPE clause was added in MySQL 5.0.6. If present, it should
be specified as `TABLE', `FUNCTION', or `PROCEDURE' when the following
object is a table, a stored function, or a stored procedure.

The privileges for a database, table, column, or routine are formed
additively as the logical `OR' of the privileges at each of the
privilege levels. For example, if a user has a global `SELECT'
privilege, the privilege cannot be denied by an absence of the
privilege at the database, table, or column level. Details of the
privilege-checking procedure are presented in *Note request-access::.

MySQL enables you to grant privileges on databases or tables that do
not exist. For tables, the privileges to be granted must include the
`CREATE' privilege.  _This behavior is by design_, and is intended to
enable the database administrator to prepare user accounts and
privileges for databases or tables that are to be created at a later
time.

*Important*:

_MySQL does not automatically revoke any privileges when you drop a
database or table_. However, if you drop a routine, any routine-level
privileges granted for that routine are revoked.

* Account Names and Passwords *

The USER value indicates the MySQL account to which the *Note `GRANT':
grant.  statement applies. To accommodate granting rights to users from
arbitrary hosts, MySQL supports specifying the USER value in the form
`USER_NAME@HOST_NAME'.  If a USER_NAME or HOST_NAME value is legal as an
unquoted identifier, you need not quote it. However, quotation marks
are necessary to specify a USER_NAME string containing special
characters (such as ``-''), or a HOST_NAME string containing special
characters or wildcard characters (such as ``%''); for example,
`'test-user'@'%.com''. Quote the user name and host name separately.

You can specify wildcards in the host name. For example,
`USER_NAME@'%.example.com'' applies to USER_NAME for any host in the
`example.com' domain, and `USER_NAME@'192.168.1.%'' applies to
USER_NAME for any host in the `192.168.1' class C subnet.

The simple form USER_NAME is a synonym for `USER_NAME@'%''.

_MySQL does not support wildcards in user names_. To refer to an
anonymous user, specify an account with an empty user name with the
*Note `GRANT': grant. statement:

     GRANT ALL ON test.* TO ''@'localhost' ...

In this case, any user who connects from the local host with the
correct password for the anonymous user will be permitted access, with
the privileges associated with the anonymous-user account.

For additional information about user name and host name values in
account names, see *Note account-names::.

To specify quoted values, quote database, table, column, and routine
names as identifiers. Quote user names and host names as identifiers or
as strings. Quote passwords as strings. For string-quoting and
identifier-quoting guidelines, see *Note string-literals::, and *Note
identifiers::.

The ``_'' and ``%'' wildcards are permitted when specifying database
names in *Note `GRANT': grant. statements that grant privileges at the
global or database levels. This means, for example, that if you want to
use a ``_'' character as part of a database name, you should specify it
as ``\_'' in the *Note `GRANT': grant. statement, to prevent the user
from being able to access additional databases matching the wildcard
pattern; for example, `GRANT ... ON `foo\_bar`.* TO ...'.

*Warning*:

If you permit anonymous users to connect to the MySQL server, you
should also grant privileges to all local users as
`USER_NAME@localhost'.  Otherwise, the anonymous user account for
`localhost' in the `mysql.user' table (created during MySQL
installation) is used when named users try to log in to the MySQL
server from the local machine. For details, see *Note
connection-access::.

To determine whether the preceding warning applies to you, execute the
following query, which lists any anonymous users:

     SELECT Host, User FROM mysql.user WHERE User='';

To avoid the problem just described, delete the local anonymous user
account using this statement:

     DROP USER ''@'localhost';

*Note `GRANT': grant. supports host names up to 60 characters long.
Database, table, column, and routine names can be up to 64 characters.
User names can be up to 16 characters.

*Warning*:

_The permissible length for user names cannot be changed by altering
the `mysql.user' table.  Attempting to do so results in unpredictable
behavior which may even make it impossible for users to log in to the
MySQL server_. You should never alter any of the tables in the `mysql'
database in any manner whatsoever except by means of the procedure
described in *Note mysql-upgrade::.

The user specification may indicate how the user should authenticate
when connecting to the server, through inclusion of an `IDENTIFIED BY'
clause. The syntax is the same as for the *Note `CREATE USER':
create-user.  statement. See *Note create-user::.

When the `IDENTIFIED BY' clause is present and you have global grant
privileges, the password becomes the new password for the account, even
if the account exists and already has a password. With no `IDENTIFIED
BY' clause, the account password remains unchanged.

If the `NO_AUTO_CREATE_USER' SQL mode is not enabled and the account
named in a *Note `GRANT': grant. statement does not exist in the
`mysql.user' table, *Note `GRANT': grant. creates it. If you specify no
`IDENTIFIED BY' clause or provide an empty password, the user has no
password. _This is very insecure._

If `NO_AUTO_CREATE_USER' is enabled and the account does not exist,
*Note `GRANT': grant. fails and does not create the account unless the
`IDENTIFIED BY' clause is given to provide a nonempty password.

*Important*:

*Note `GRANT': grant. may be recorded in server logs or in a history
file such as `~/.mysql_history', which means that plaintext passwords
may be read by anyone having read access to that information. See *Note
password-security::.

* Other Account Characteristics *

The `WITH' clause is used for several purposes:

   * To enable a user to grant privileges to other users

   * To specify resource limits for a user

   * To specify whether and how a user must use secure connections to
     the server

The `WITH GRANT OPTION' clause gives the user the ability to give to
other users any privileges the user has at the specified privilege
level. You should be careful to whom you give the `GRANT OPTION'
privilege because two users with different privileges may be able to
combine privileges!

You cannot grant another user a privilege which you yourself do not
have; the `GRANT OPTION' privilege enables you to assign only those
privileges which you yourself possess.

Be aware that when you grant a user the `GRANT OPTION' privilege at a
particular privilege level, any privileges the user possesses (or may
be given in the future) at that level can also be granted by that user
to other users. Suppose that you grant a user the `INSERT' privilege on
a database. If you then grant the `SELECT' privilege on the database
and specify `WITH GRANT OPTION', that user can give to other users not
only the `SELECT' privilege, but also `INSERT'. If you then grant the
`UPDATE' privilege to the user on the database, the user can grant
`INSERT', `SELECT', and `UPDATE'.

For a nonadministrative user, you should not grant the `ALTER'
privilege globally or for the `mysql' database. If you do that, the user
can try to subvert the privilege system by renaming tables!

For additional information about security risks associated with
particular privileges, see *Note privileges-provided::.

Several `WITH' clause options specify limits on use of server resources
by an account:

   * The `MAX_QUERIES_PER_HOUR COUNT', `MAX_UPDATES_PER_HOUR COUNT', and
     `MAX_CONNECTIONS_PER_HOUR COUNT' limits restrict the number of
     queries, updates, and connections to the server permitted to this
     account during any given one-hour period. (Queries for which
     results are served from the query cache do not count against the
     `MAX_QUERIES_PER_HOUR' limit.) If COUNT is `0' (the default), this
     means that there is no limitation for the account.

   * The `MAX_USER_CONNECTIONS COUNT' limit, implemented in MySQL
     5.0.3, restricts the maximum number of simultaneous connections to
     the server by the account. A nonzero COUNT specifies the limit for
     the account explicitly. If COUNT is `0' (the default), the server
     determines the number of simultaneous connections for the account
     from the global value of the `max_user_connections' system
     variable. If `max_user_connections' is also zero, there is no
     limit for the account.

To specify resource limits for an existing user without affecting
existing privileges, use *Note `GRANT USAGE': grant. at the global
level (`ON *.*') and name the limits to be changed. For example:

     GRANT USAGE ON *.* TO ...
       WITH MAX_QUERIES_PER_HOUR 500 MAX_UPDATES_PER_HOUR 100;

Limits not specified retain their current values.

For more information on restricting access to server resources, see
*Note user-resources::.

MySQL can check X509 certificate attributes in addition to the usual
authentication that is based on the user name and password. To specify
SSL-related options for a MySQL account, use the `REQUIRE' clause of the
*Note `GRANT': grant. statement. (For background information on the use
of SSL with MySQL, see *Note secure-connections::.)

There are a number of different possibilities for limiting connection
types for a given account:

   * `REQUIRE NONE' indicates that the account has no SSL or X509
     requirements. This is the default if no SSL-related `REQUIRE'
     options are specified. Unencrypted connections are permitted if
     the user name and password are valid. However, encrypted
     connections can also be used, at the client's option, if the
     client has the proper certificate and key files. That is, the
     client need not specify any SSL command options, in which case the
     connection will be unencrypted. To use an encrypted connection,
     the client must specify either the `--ssl-ca' option, or all three
     of the `--ssl-ca', `--ssl-key', and `--ssl-cert' options.

   * The `REQUIRE SSL' option tells the server to permit only
     SSL-encrypted connections for the account.

          GRANT ALL PRIVILEGES ON test.* TO 'root'@'localhost'
            IDENTIFIED BY 'goodsecret' REQUIRE SSL;

     To connect, the client must specify the `--ssl-ca' option, and may
     additionally specify the `--ssl-key' and `--ssl-cert' options.

   * `REQUIRE X509' means that the client must have a valid certificate
     but that the exact certificate, issuer, and subject do not matter.
     The only requirement is that it should be possible to verify its
     signature with one of the CA certificates.

          GRANT ALL PRIVILEGES ON test.* TO 'root'@'localhost'
            IDENTIFIED BY 'goodsecret' REQUIRE X509;

     To connect, the client must specify the `--ssl-ca', `--ssl-key',
     and `--ssl-cert' options. This is also true for `ISSUER' and
     `SUBJECT' because those `REQUIRE' options imply `X509'.

   * `REQUIRE ISSUER 'ISSUER'' places the restriction on connection
     attempts that the client must present a valid X509 certificate
     issued by CA `'ISSUER''. If the client presents a certificate that
     is valid but has a different issuer, the server rejects the
     connection. Use of X509 certificates always implies encryption, so
     the `SSL' option is unnecessary in this case.

          GRANT ALL PRIVILEGES ON test.* TO 'root'@'localhost'
            IDENTIFIED BY 'goodsecret'
            REQUIRE ISSUER '/C=FI/ST=Some-State/L=Helsinki/
              O=MySQL Finland AB/CN=Tonu Samuel/emailAddress=tonu@example.com';

     The `'ISSUER'' value should be entered as a single string.

     *Note*:

     If MySQL is linked against a version of OpenSSL older than 0.9.6h,
     use `Email' rather than `emailAddress' in the `'ISSUER'' value.

   * `REQUIRE SUBJECT 'SUBJECT'' places the restriction on connection
     attempts that the client must present a valid X509 certificate
     containing the subject SUBJECT. If the client presents a
     certificate that is valid but has a different subject, the server
     rejects the connection.

          GRANT ALL PRIVILEGES ON test.* TO 'root'@'localhost'
            IDENTIFIED BY 'goodsecret'
            REQUIRE SUBJECT '/C=EE/ST=Some-State/L=Tallinn/
              O=MySQL demo client certificate/
              CN=Tonu Samuel/emailAddress=tonu@example.com';

     The `'SUBJECT'' value should be entered as a single string.

     *Note*:

     Regarding `emailAddress', see the note in the description of
     `REQUIRE ISSUER'.

   * `REQUIRE CIPHER 'CIPHER'' is needed to ensure that ciphers and key
     lengths of sufficient strength are used. SSL itself can be weak if
     old algorithms using short encryption keys are used. Using this
     option, you can ask that a specific cipher method is used for a
     connection.

          GRANT ALL PRIVILEGES ON test.* TO 'root'@'localhost'
            IDENTIFIED BY 'goodsecret'
            REQUIRE CIPHER 'EDH-RSA-DES-CBC3-SHA';

The `SUBJECT', `ISSUER', and `CIPHER' options can be combined in the
`REQUIRE' clause like this:

     GRANT ALL PRIVILEGES ON test.* TO 'root'@'localhost'
       IDENTIFIED BY 'goodsecret'
       REQUIRE SUBJECT '/C=EE/ST=Some-State/L=Tallinn/
         O=MySQL demo client certificate/
         CN=Tonu Samuel/emailAddress=tonu@example.com'
       AND ISSUER '/C=FI/ST=Some-State/L=Helsinki/
         O=MySQL Finland AB/CN=Tonu Samuel/emailAddress=tonu@example.com'
       AND CIPHER 'EDH-RSA-DES-CBC3-SHA';

The order of the options does not matter, but no option can be
specified twice. The `AND' keyword is optional between `REQUIRE'
options.

If you are using table, column, or routine privileges for even one
user, the server examines table, column, and routine privileges for all
users and this slows down MySQL a bit.  Similarly, if you limit the
number of queries, updates, or connections for any users, the server
must monitor these values.

* MySQL and Standard SQL Versions of *Note `GRANT': grant.  *

The biggest differences between the MySQL and standard SQL versions of
*Note `GRANT': grant. are:

   * MySQL associates privileges with the combination of a host name
     and user name and not with only a user name.

   * Standard SQL does not have global or database-level privileges,
     nor does it support all the privilege types that MySQL supports.

   * MySQL does not support the standard SQL `UNDER' privilege, and
     does not support the `TRIGGER'
     (http://dev.mysql.com/doc/refman/5.1/en/privileges-provided.html#priv_trigger)
     privilege until MySQL 5.1.6.

   * Standard SQL privileges are structured in a hierarchical manner.
     If you remove a user, all privileges the user has been granted are
     revoked. This is also true in MySQL 5.0.2 and up if you use *Note
     `DROP USER': drop-user.  Before 5.0.2, the granted privileges are
     not automatically revoked; you must revoke them yourself. See
     *Note drop-user::.

   * In standard SQL, when you drop a table, all privileges for the
     table are revoked. In standard SQL, when you revoke a privilege,
     all privileges that were granted based on that privilege are also
     revoked. In MySQL, privileges can be dropped only with explicit
     *Note `DROP USER': drop-user. or *Note `REVOKE': revoke.
     statements or by manipulating the MySQL grant tables directly.

   * In MySQL, it is possible to have the `INSERT' privilege for only
     some of the columns in a table. In this case, you can still
     execute *Note `INSERT': insert. statements on the table, provided
     that you insert values only for those columns for which you have
     the `INSERT' privilege. The omitted columns are set to their
     implicit default values if strict SQL mode is not enabled. In
     strict mode, the statement is rejected if any of the omitted
     columns have no default value. (Standard SQL requires you to have
     the `INSERT' privilege on all columns.) *Note server-sql-mode::,
     discusses strict mode. *Note data-type-defaults::, discusses
     implicit default values.


File: manual.info,  Node: rename-user,  Next: revoke,  Prev: grant,  Up: account-management-sql

13.7.1.4 `RENAME USER' Syntax
.............................

     RENAME USER OLD_USER TO NEW_USER
         [, OLD_USER TO NEW_USER] ...

The *Note `RENAME USER': rename-user. statement renames existing MySQL
accounts. To use it, you must have the global `CREATE USER' privilege
or the `UPDATE' privilege for the `mysql' database. An error occurs if
any old account does not exist or any new account exists. Each account
name uses the format described in *Note account-names::. For example:

     RENAME USER 'jeffrey'@'localhost' TO 'jeff'@'127.0.0.1';

If you specify only the user name part of the account name, a host name
part of `'%'' is used.

*Note `RENAME USER': rename-user. causes the privileges held by the old
user to be those held by the new user. However, *Note `RENAME USER':
rename-user. does not automatically drop or invalidate databases or
objects within them that the old user created. This includes stored
programs or views for which the `DEFINER' attribute names the old user.
Attempts to access such objects may produce an error if they execute in
definer security context. (For information about security context, see
*Note stored-programs-security::.)

The privilege changes take effect as indicated in *Note
privilege-changes::.

The *Note `RENAME USER': rename-user. statement was added in MySQL
5.0.2.


File: manual.info,  Node: revoke,  Next: set-password,  Prev: rename-user,  Up: account-management-sql

13.7.1.5 `REVOKE' Syntax
........................

     REVOKE
         PRIV_TYPE [(COLUMN_LIST)]
           [, PRIV_TYPE [(COLUMN_LIST)]] ...
         ON [OBJECT_TYPE] PRIV_LEVEL
         FROM USER [, USER] ...

     REVOKE ALL PRIVILEGES, GRANT OPTION
         FROM USER [, USER] ...

The *Note `REVOKE': revoke. statement enables system administrators to
revoke privileges from MySQL accounts.  Each account name uses the
format described in *Note account-names::. For example:

     REVOKE INSERT ON *.* FROM 'jeffrey'@'localhost';

If you specify only the user name part of the account name, a host name
part of `'%'' is used.

For details on the levels at which privileges exist, the permissible
PRIV_TYPE and PRIV_LEVEL values, and the syntax for specifying users
and passwords, see *Note grant::

To use the first *Note `REVOKE': revoke. syntax, you must have the
`GRANT OPTION' privilege, and you must have the privileges that you are
revoking.

To revoke all privileges, use the second syntax, which drops all
global, database, table, column, and routine privileges for the named
user or users:

     REVOKE ALL PRIVILEGES, GRANT OPTION FROM USER [, USER] ...

To use this *Note `REVOKE': revoke. syntax, you must have the global
`CREATE USER' privilege or the `UPDATE' privilege for the `mysql'
database.

*Note `REVOKE': revoke. removes privileges, but does not drop
`mysql.user' table entries. To remove a user account entirely, use
*Note `DROP USER': drop-user. (see *Note drop-user::) or *Note
`DELETE': delete.

If the grant tables hold privilege rows that contain mixed-case
database or table names and the `lower_case_table_names' system
variable is set to a nonzero value, *Note `REVOKE': revoke. cannot be
used to revoke these privileges. It will be necessary to manipulate the
grant tables directly. (*Note `GRANT': grant. will not create such rows
when `lower_case_table_names' is set, but such rows might have been
created prior to setting the variable.)

To verify an account's privileges after a *Note `REVOKE': revoke.
operation, use *Note `SHOW GRANTS': show-grants. See *Note
show-grants::.


File: manual.info,  Node: set-password,  Prev: revoke,  Up: account-management-sql

13.7.1.6 `SET PASSWORD' Syntax
..............................

     SET PASSWORD [FOR USER] =
         {
             PASSWORD('SOME PASSWORD')
           | OLD_PASSWORD('SOME PASSWORD')
           | 'ENCRYPTED PASSWORD'
         }

The *Note `SET PASSWORD': set-password. statement assigns a password to
an existing MySQL user account.

If the password is specified using the `PASSWORD()' or `OLD_PASSWORD()'
function, the literal text of the password should be given. If the
password is specified without using either function, the password
should be the already-encrypted password value as returned by
`PASSWORD()'.

With no `FOR' clause, this statement sets the password for the current
user. Any client that has connected to the server using a nonanonymous
account can change the password for that account.

In MySQL 5.0, enabling the `read_only' system variable does not prevent
use of `SET PASSWORD'.

With a `FOR' clause, this statement sets the password for a specific
account on the current server host. Only clients that have the *Note
`UPDATE': update.  privilege for the `mysql' database can do this.  The
USER value should be given in `USER_NAME@HOST_NAME' format, where
USER_NAME and HOST_NAME are exactly as they are listed in the `User' and
`Host' columns of the `mysql.user' table entry. For example, if you had
an entry with `User' and `Host' column values of `'bob'' and
`'%.loc.gov'', you would write the statement like this:

     SET PASSWORD FOR 'bob'@'%.loc.gov' = PASSWORD('NEWPASS');

That is equivalent to the following statements:

     UPDATE mysql.user SET Password=PASSWORD('NEWPASS')
       WHERE User='bob' AND Host='%.loc.gov';
     FLUSH PRIVILEGES;

Another way to set the password is to use *Note `GRANT': grant.:

     GRANT USAGE ON *.* TO 'bob'@'%.loc.gov' IDENTIFIED BY 'NEWPASS';

*Important*:

*Note `SET PASSWORD': set-password. may be recorded in server logs or
in a history file such as `~/.mysql_history', which means that
plaintext passwords may be read by anyone having read access to that
information. See *Note password-security::.

*Note*:

If you are connecting to a MySQL 4.1 or later server using a pre-4.1
client program, do not use the preceding *Note `SET PASSWORD':
set-password. or *Note `UPDATE': update. statement without reading
*Note password-hashing::, first. The password format changed in MySQL
4.1, and under certain circumstances it is possible that if you change
your password, you might not be able to connect to the server afterward.

To see which account the server authenticated you as, invoke the
`CURRENT_USER()' function.

For more information about setting passwords, see *Note
assigning-passwords::


File: manual.info,  Node: table-maintenance-sql,  Next: plugin-sql,  Prev: account-management-sql,  Up: sql-syntax-server-administration

13.7.2 Table Maintenance Statements
-----------------------------------

* Menu:

* analyze-table::                `ANALYZE TABLE' Syntax
* backup-table::                 `BACKUP TABLE' Syntax
* check-table::                  `CHECK TABLE' Syntax
* checksum-table::               `CHECKSUM TABLE' Syntax
* optimize-table::               `OPTIMIZE TABLE' Syntax
* repair-table::                 `REPAIR TABLE' Syntax
* restore-table::                `RESTORE TABLE' Syntax


File: manual.info,  Node: analyze-table,  Next: backup-table,  Prev: table-maintenance-sql,  Up: table-maintenance-sql

13.7.2.1 `ANALYZE TABLE' Syntax
...............................

     ANALYZE [NO_WRITE_TO_BINLOG | LOCAL] TABLE
         TBL_NAME [, TBL_NAME] ...

*Note `ANALYZE TABLE': analyze-table. analyzes and stores the key
distribution for a table. During the analysis, the table is locked with
a read lock for `MyISAM', `BDB', and `InnoDB'. This statement works
with `MyISAM', `BDB', `InnoDB', and `NDB' tables. For `MyISAM' tables,
this statement is equivalent to using *Note `myisamchk --analyze':
myisamchk.-

For more information on how the analysis works within `InnoDB', see
*Note innodb-restrictions::.

MySQL uses the stored key distribution to decide the order in which
tables should be joined when you perform a join on something other than
a constant. In addition, key distributions can be used when deciding
which indexes to use for a specific table within a query.

This statement requires `SELECT' and `INSERT' privileges for the table.

*Note `ANALYZE TABLE': analyze-table. returns a result set with the
following columns.

Column      Value
`Table'     The table name
`Op'        Always `analyze'
`Msg_type'  `status', `error', `info', `note', or
            `warning'
`Msg_text'  An informational message

You can check the stored key distribution with the *Note `SHOW INDEX':
show-index. statement. See *Note show-index::.

If the table has not changed since the last *Note `ANALYZE TABLE':
analyze-table. statement, the table is not analyzed again.

By default, *Note `ANALYZE TABLE': analyze-table.  statements are
written to the binary log so that they will be replicated to
replication slaves. Logging can be suppressed with the optional
`NO_WRITE_TO_BINLOG' keyword or its alias `LOCAL'.


File: manual.info,  Node: backup-table,  Next: check-table,  Prev: analyze-table,  Up: table-maintenance-sql

13.7.2.2 `BACKUP TABLE' Syntax
..............................

     BACKUP TABLE TBL_NAME [, TBL_NAME] ... TO '/PATH/TO/BACKUP/DIRECTORY'

*Note*:

This statement is deprecated and is removed in MySQL 5.5. As an
alternative, *Note `mysqldump': mysqldump. or *Note `mysqlhotcopy':
mysqlhotcopy. can be used instead.

*Note `BACKUP TABLE': backup-table. copies to the backup directory the
minimum number of table files needed to restore the table, after
flushing any buffered changes to disk. The statement works only for
`MyISAM' tables. It copies the `.frm' definition and `.MYD' data files.
The `.MYI' index file can be rebuilt from those two files. The
directory should be specified as a full path name. To restore the
table, use *Note `RESTORE TABLE': restore-table.

During the backup, a read lock is held for each table, one at time, as
they are being backed up. If you want to back up several tables as a
snapshot (preventing any of them from being changed during the backup
operation), issue a *Note `LOCK TABLES': lock-tables. statement first,
to obtain a read lock for all tables in the group.

*Note `BACKUP TABLE': backup-table. returns a result set with the
following columns.

Column      Value
`Table'     The table name
`Op'        Always `backup'
`Msg_type'  `status', `error', `info', `note', or
            `warning'
`Msg_text'  An informational message


File: manual.info,  Node: check-table,  Next: checksum-table,  Prev: backup-table,  Up: table-maintenance-sql

13.7.2.3 `CHECK TABLE' Syntax
.............................

     CHECK TABLE TBL_NAME [, TBL_NAME] ... [OPTION] ...

     OPTION = {FOR UPGRADE | QUICK | FAST | MEDIUM | EXTENDED | CHANGED}

*Note `CHECK TABLE': check-table. checks a table or tables for errors.
*Note `CHECK TABLE': check-table.  works for `MyISAM', `InnoDB', and
(as of MySQL 5.0.16) `ARCHIVE' tables. For `MyISAM' tables, the key
statistics are updated as well.

As of MySQL 5.0.2, *Note `CHECK TABLE': check-table.  can also check
views for problems, such as tables that are referenced in the view
definition that no longer exist.

*Note `CHECK TABLE': check-table. returns a result set with the
following columns.

Column      Value
`Table'     The table name
`Op'        Always `check'
`Msg_type'  `status', `error', `info', `note', or
            `warning'
`Msg_text'  An informational message

Note that the statement might produce many rows of information for each
checked table. The last row has a `Msg_type' value of `status' and the
`Msg_text' normally should be `OK'. If you don't get `OK', or `Table is
already up to date' you should normally run a repair of the table. See
*Note myisam-table-maintenance::. `Table is already up to date' means
that the storage engine for the table indicated that there was no need
to check the table.

The `FOR UPGRADE' option checks whether the named tables are compatible
with the current version of MySQL.  This option was added in MySQL
5.0.19. With `FOR UPGRADE', the server checks each table to determine
whether there have been any incompatible changes in any of the table's
data types or indexes since the table was created. If not, the check
succeeds. Otherwise, if there is a possible incompatibility, the server
runs a full check on the table (which might take some time). If the
full check succeeds, the server marks the table's `.frm' file with the
current MySQL version number. Marking the `.frm' file ensures that
further checks for the table with the same version of the server will
be fast.

Incompatibilities might occur because the storage format for a data
type has changed or because its sort order has changed. Our aim is to
avoid these changes, but occasionally they are necessary to correct
problems that would be worse than an incompatibility between releases.

Currently, `FOR UPGRADE' discovers these incompatibilities:

   * The indexing order for end-space in *Note `TEXT': blob. columns for
     `InnoDB' and `MyISAM' tables changed between MySQL 4.1 and 5.0.

   * The storage method of the new *Note `DECIMAL': numeric-types. data
     type changed between MySQL 5.0.3 and 5.0.5.

   * As of MySQL 5.0.62, if your table was created by a different
     version of the MySQL server than the one you are currently
     running, `FOR UPGRADE' indicates that the table has an `.frm' file
     with an incompatible version. In this case, the result set returned
     by *Note `CHECK TABLE': check-table. contains a line with a
     `Msg_type' value of `error' and a `Msg_text' value of `Table
     upgrade required. Please do "REPAIR TABLE `TBL_NAME`" to fix it!'

   * Changes are sometimes made to character sets or collations that
     require table indexes to be rebuilt. For details about these
     changes and when `FOR UPGRADE' detects them, see *Note
     checking-table-incompatibilities::.

The other check options that can be given are shown in the following
table. These options are passed to the storage engine, which may use
them or not. `MyISAM' uses them; they are ignored for `InnoDB' tables
and views.

Type        Meaning
`QUICK'     Do not scan the rows to check for incorrect links.
`FAST'      Check only tables that have not been closed properly.
`CHANGED'   Check only tables that have been changed since the last
            check or that have not been closed properly.
`MEDIUM'    Scan rows to verify that deleted links are valid. This also
            calculates a key checksum for the rows and verifies this
            with a calculated checksum for the keys.
`EXTENDED'  Do a full key lookup for all keys for each row. This ensures
            that the table is 100% consistent, but takes a long time.

If none of the options `QUICK', `MEDIUM', or `EXTENDED' are specified,
the default check type for dynamic-format `MyISAM' tables is `MEDIUM'.
This has the same result as running *Note `myisamchk --medium-check
TBL_NAME': myisamchk. on the table. The default check type also is
`MEDIUM' for static-format `MyISAM' tables, unless `CHANGED' or `FAST'
is specified. In that case, the default is `QUICK'. The row scan is
skipped for `CHANGED' and `FAST' because the rows are very seldom
corrupted.

You can combine check options, as in the following example that does a
quick check on the table to determine whether it was closed properly:

     CHECK TABLE test_table FAST QUICK;

*Note*:

In some cases, *Note `CHECK TABLE': check-table.  changes the table.
This happens if the table is marked as `corrupted' or `not closed
properly' but *Note `CHECK TABLE': check-table. does not find any
problems in the table. In this case, *Note `CHECK TABLE': check-table.
marks the table as okay.

If a table is corrupted, it is most likely that the problem is in the
indexes and not in the data part. All of the preceding check types
check the indexes thoroughly and should thus find most errors.

If you just want to check a table that you assume is okay, you should
use no check options or the `QUICK' option. The latter should be used
when you are in a hurry and can take the very small risk that `QUICK'
does not find an error in the data file. (In most cases, under normal
usage, MySQL should find any error in the data file. If this happens,
the table is marked as `corrupted' and cannot be used until it is
repaired.)

`FAST' and `CHANGED' are mostly intended to be used from a script (for
example, to be executed from `cron') if you want to check tables from
time to time. In most cases, `FAST' is to be preferred over `CHANGED'.
(The only case when it is not preferred is when you suspect that you
have found a bug in the `MyISAM' code.)

`EXTENDED' is to be used only after you have run a normal check but
still get strange errors from a table when MySQL tries to update a row
or find a row by key. This is very unlikely if a normal check has
succeeded.

Use of *Note `CHECK TABLE ... EXTENDED': check-table. might influence
the execution plan generated by the query optimizer.

Some problems reported by *Note `CHECK TABLE': check-table. cannot be
corrected automatically:

   * `Found row where the auto_increment column has the value 0'.

     This means that you have a row in the table where the
     `AUTO_INCREMENT' index column contains the value 0. (It is
     possible to create a row where the `AUTO_INCREMENT' column is 0 by
     explicitly setting the column to 0 with an *Note `UPDATE': update.
     statement.)

     This is not an error in itself, but could cause trouble if you
     decide to dump the table and restore it or do an *Note `ALTER
     TABLE': alter-table. on the table. In this case, the
     `AUTO_INCREMENT' column changes value according to the rules of
     `AUTO_INCREMENT' columns, which could cause problems such as a
     duplicate-key error.

     To get rid of the warning, simply execute an *Note `UPDATE':
     update. statement to set the column to some value other than 0.

   * If *Note `CHECK TABLE': check-table. finds a problem for an
     `InnoDB' table, the server shuts down to prevent error
     propagation. Details of the error will be written to the error log.


File: manual.info,  Node: checksum-table,  Next: optimize-table,  Prev: check-table,  Up: table-maintenance-sql

13.7.2.4 `CHECKSUM TABLE' Syntax
................................

     CHECKSUM TABLE TBL_NAME [, TBL_NAME] ... [ QUICK | EXTENDED ]

*Note `CHECKSUM TABLE': checksum-table. reports a table checksum.

With `QUICK', the live table checksum is reported if it is available,
or `NULL' otherwise. This is very fast. A live checksum is enabled by
specifying the `CHECKSUM=1' table option when you create the table;
currently, this is supported only for `MyISAM' tables. See *Note
create-table::.

With `EXTENDED', the entire table is read row by row and the checksum
is calculated. This can be very slow for large tables.

If neither `QUICK' nor `EXTENDED' is specified, MySQL returns a live
checksum if the table storage engine supports it and scans the table
otherwise.

For a nonexistent table, *Note `CHECKSUM TABLE': checksum-table.
returns `NULL' and, as of MySQL 5.0.3, generates a warning.

The checksum value depends on the table row format. If the row format
changes, the checksum also changes. For example, the storage format for
*Note `VARCHAR': char.  changed between MySQL 4.1 and 5.0, so if a 4.1
table is upgraded to MySQL 5.0, the checksum value may change.

*Important*:

If the checksums for two tables are different, then it is almost
certain that the tables are different in some way.  However, because
the hashing function used by *Note `CHECKSUM TABLE': checksum-table. is
not guaranteed to be collision-free, there is a slight chance that two
tables which are not identical can produce the same checksum.


File: manual.info,  Node: optimize-table,  Next: repair-table,  Prev: checksum-table,  Up: table-maintenance-sql

13.7.2.5 `OPTIMIZE TABLE' Syntax
................................

     OPTIMIZE [NO_WRITE_TO_BINLOG | LOCAL] TABLE
         TBL_NAME [, TBL_NAME] ...

*Note `OPTIMIZE TABLE': optimize-table. should be used if you have
deleted a large part of a table or if you have made many changes to a
table with variable-length rows (tables that have *Note `VARCHAR': char,
*Note `VARBINARY': binary-varbinary, *Note `BLOB': blob, or *Note
`TEXT': blob. columns). Deleted rows are maintained in a linked list
and subsequent *Note `INSERT': insert. operations reuse old row
positions. You can use *Note `OPTIMIZE TABLE': optimize-table. to
reclaim the unused space and to defragment the data file. After
extensive changes to a table, this statement may also improve
performance of statements that use the table, sometimes significantly.

This statement requires `SELECT' and `INSERT' privileges for the table.

*Note `OPTIMIZE TABLE': optimize-table. works _only_ for `MyISAM',
`InnoDB', and (as of MySQL 5.0.16) `ARCHIVE' tables. It does _not_ work
for tables created using any other storage engine.

For `MyISAM' tables, *Note `OPTIMIZE TABLE': optimize-table. works as
follows:

  1. If the table has deleted or split rows, repair the table.

  2. If the index pages are not sorted, sort them.

  3. If the table's statistics are not up to date (and the repair could
     not be accomplished by sorting the index), update them.

For `BDB' tables, *Note `OPTIMIZE TABLE': optimize-table. currently is
mapped to *Note `ANALYZE TABLE': analyze-table. See *Note
analyze-table::.

For `InnoDB' tables, *Note `OPTIMIZE TABLE': optimize-table. is mapped
to *Note `ALTER TABLE': alter-table, which rebuilds the table to update
index statistics and free unused space in the clustered index.

You can make *Note `OPTIMIZE TABLE': optimize-table. work on other
storage engines by starting *Note `mysqld': mysqld.  with the
`--skip-new' or `--safe-mode' option. In this case, *Note `OPTIMIZE
TABLE': optimize-table. is just mapped to *Note `ALTER TABLE':
alter-table.

*Note `OPTIMIZE TABLE': optimize-table. returns a result set with the
following columns.

Column      Value
`Table'     The table name
`Op'        Always `optimize'
`Msg_type'  `status', `error', `info', `note', or
            `warning'
`Msg_text'  An informational message

Note that MySQL locks the table during the time *Note `OPTIMIZE TABLE':
optimize-table. is running.

By default, *Note `OPTIMIZE TABLE': optimize-table.  statements are
written to the binary log so that they will be replicated to
replication slaves. Logging can be suppressed with the optional
`NO_WRITE_TO_BINLOG' keyword or its alias `LOCAL'.

*Note `OPTIMIZE TABLE': optimize-table. does not sort R-tree indexes,
such as spatial indexes on `POINT' columns. (Bug #23578)


File: manual.info,  Node: repair-table,  Next: restore-table,  Prev: optimize-table,  Up: table-maintenance-sql

13.7.2.6 `REPAIR TABLE' Syntax
..............................

     REPAIR [NO_WRITE_TO_BINLOG | LOCAL] TABLE
         TBL_NAME [, TBL_NAME] ...
         [QUICK] [EXTENDED] [USE_FRM]

*Note `REPAIR TABLE': repair-table. repairs a possibly corrupted table.
By default, it has the same effect as *Note `myisamchk --recover
TBL_NAME': myisamchk.  *Note `REPAIR TABLE': repair-table. works for
`MyISAM' and for `ARCHIVE' tables. See *Note myisam-storage-engine::,
and *Note archive-storage-engine::.

This statement requires `SELECT' and `INSERT' privileges for the table.

Normally, you should never have to run this statement. However, if
disaster strikes, *Note `REPAIR TABLE': repair-table.  is very likely
to get back all your data from a `MyISAM' table. If your tables become
corrupted often, you should try to find the reason for it, to eliminate
the need to use *Note `REPAIR TABLE': repair-table. See *Note
crashing::, and *Note myisam-table-problems::.

*Caution*:

It is best to make a backup of a table before performing a table repair
operation; under some circumstances the operation might cause data
loss. Possible causes include but are not limited to file system
errors. See *Note backup-and-recovery::.

*Warning*:

If the server crashes during a *Note `REPAIR TABLE': repair-table.
operation, it is essential after restarting it that you immediately
execute another *Note `REPAIR TABLE': repair-table. statement for the
table before performing any other operations on it. In the worst case,
you might have a new clean index file without information about the
data file, and then the next operation you perform could overwrite the
data file. This is an unlikely but possible scenario that underscores
the value of making a backup first.

*Note `REPAIR TABLE': repair-table. returns a result set with the
following columns.

Column      Value
`Table'     The table name
`Op'        Always `repair'
`Msg_type'  `status', `error', `info', `note', or
            `warning'
`Msg_text'  An informational message

The *Note `REPAIR TABLE': repair-table. statement might produce many
rows of information for each repaired table. The last row has a
`Msg_type' value of `status' and `Msg_test' normally should be `OK'. If
you do not get `OK' for a `MyISAM' table, you should try repairing it
with *Note `myisamchk --safe-recover': myisamchk. (*Note `REPAIR
TABLE': repair-table. does not implement all the options of *Note
`myisamchk': myisamchk.) With *Note `myisamchk --safe-recover':
myisamchk, you can also use options that *Note `REPAIR TABLE':
repair-table. does not support, such as `--max-record-length'.

If you use the `QUICK' option, *Note `REPAIR TABLE': repair-table.
tries to repair only the index file, and not the data file. This type
of repair is like that done by *Note `myisamchk --recover --quick':
myisamchk.

If you use the `EXTENDED' option, MySQL creates the index row by row
instead of creating one index at a time with sorting. This type of
repair is like that done by *Note `myisamchk --safe-recover': myisamchk.

The `USE_FRM' option is available for use if the `.MYI' index file is
missing or if its header is corrupted. This option tells MySQL not to
trust the information in the `.MYI' file header and to re-create it
using information from the `.frm' file. This kind of repair cannot be
done with *Note `myisamchk': myisamchk.

*Note*:

Use the `USE_FRM' option _only_ if you cannot use regular `REPAIR'
modes! Telling the server to ignore the `.MYI' file makes important
table metadata stored in the `.MYI' unavailable to the repair process,
which can have deleterious consequences:

   * The current `AUTO_INCREMENT' value is lost.

   * The link to deleted records in the table is lost, which means that
     free space for deleted records will remain unoccupied thereafter.

   * The `.MYI' header indicates whether the table is compressed. If
     the server ignores this information, it cannot tell that a table
     is compressed and repair can cause change or loss of table
     contents. This means that `USE_FRM' should not be used with
     compressed tables. That should not be necessary, anyway:
     Compressed tables are read only, so they should not become corrupt.

*Caution*:

As of MySQL 5.0.62, if you use `USE_FRM' for a table that was created
by a different version of the MySQL server than the one you are
currently running, *Note `REPAIR TABLE': repair-table. will not attempt
to repair the table. In this case, the result set returned by *Note
`REPAIR TABLE': repair-table. contains a line with a `Msg_type' value of
`error' and a `Msg_text' value of `Failed repairing incompatible .FRM
file'.

Prior to MySQL 5.0.62, _do not use_ `USE_FRM' if your table was created
by a different version of the MySQL server. Doing so risks the loss of
all rows in the table. It is particularly dangerous to use `USE_FRM'
after the server returns this message:

     Table upgrade required. Please do
     "REPAIR TABLE `TBL_NAME`" to fix it!

If `USE_FRM' is _not_ used, *Note `REPAIR TABLE': repair-table. checks
the table to see whether an upgrade is required. If so, it performs the
upgrade, following the same rules as *Note `CHECK TABLE ... FOR
UPGRADE': check-table. See *Note check-table::, for more information.
As of MySQL 5.0.62, *Note `REPAIR TABLE': repair-table. without
`USE_FRM' upgrades the `.frm' file to the current version.

By default, *Note `REPAIR TABLE': repair-table.  statements are written
to the binary log so that they will be replicated to replication
slaves. Logging can be suppressed with the optional
`NO_WRITE_TO_BINLOG' keyword or its alias `LOCAL'.

*Important*:

In the event that a table on the master becomes corrupted and you run
*Note `REPAIR TABLE': repair-table. on it, any resulting changes to the
original table are _not_ propagated to slaves.

You may be able to increase *Note `REPAIR TABLE': repair-table.
performance by setting certain system variables.  See *Note
repair-table-speed::.


File: manual.info,  Node: restore-table,  Prev: repair-table,  Up: table-maintenance-sql

13.7.2.7 `RESTORE TABLE' Syntax
...............................

     RESTORE TABLE TBL_NAME [, TBL_NAME] ... FROM '/PATH/TO/BACKUP/DIRECTORY'

*Note*:

This statement is deprecated and is removed in MySQL 5.5.

*Note `RESTORE TABLE': restore-table. restores the table or tables from
a backup that was made with *Note `BACKUP TABLE': backup-table. The
directory should be specified as a full path name.

Existing tables are not overwritten; if you try to restore over an
existing table, an error occurs. Just as for *Note `BACKUP TABLE':
backup-table, *Note `RESTORE TABLE': restore-table. currently works
only for `MyISAM' tables. Restored tables are not replicated from
master to slave.

The backup for each table consists of its `.frm' format file and `.MYD'
data file. The restore operation restores those files, and then uses
them to rebuild the `.MYI' index file. Restoring takes longer than
backing up due to the need to rebuild the indexes. The more indexes the
table has, the longer it takes.

*Note `RESTORE TABLE': restore-table. returns a result set with the
following columns.

Column      Value
`Table'     The table name
`Op'        Always `restore'
`Msg_type'  `status', `error', `info', `note', or
            `warning'
`Msg_text'  An informational message


File: manual.info,  Node: plugin-sql,  Next: set-option,  Prev: table-maintenance-sql,  Up: sql-syntax-server-administration

13.7.3 User-Defined Function Statements
---------------------------------------

* Menu:

* create-function-udf::          `CREATE FUNCTION' Syntax for User-defined Functions
* drop-function-udf::            `DROP FUNCTION' Syntax


File: manual.info,  Node: create-function-udf,  Next: drop-function-udf,  Prev: plugin-sql,  Up: plugin-sql

13.7.3.1 `CREATE FUNCTION' Syntax for User-defined Functions
............................................................

     CREATE [AGGREGATE] FUNCTION FUNCTION_NAME RETURNS {STRING|INTEGER|REAL|DECIMAL}
         SONAME SHARED_LIBRARY_NAME

A user-defined function (UDF) is a way to extend MySQL with a new
function that works like a native (built-in) MySQL function such as
`ABS()' or `CONCAT()'.

FUNCTION_NAME is the name that should be used in SQL statements to
invoke the function. The `RETURNS' clause indicates the type of the
function's return value. As of MySQL 5.0.3, *Note `DECIMAL':
numeric-types. is a legal value after `RETURNS', but currently *Note
`DECIMAL': numeric-types. functions return string values and should be
written like `STRING' functions.

SHARED_LIBRARY_NAME is the basename of the shared object file that
contains the code that implements the function. As of MySQL 5.0.67, the
file must be located in the plugin directory. This directory is given
by the value of the `plugin_dir' system variable.  If the value of
`plugin_dir' is empty, the behavior that is used before 5.0.67 applies:
The file must be located in a directory that is searched by your
system's dynamic linker. For more information, see *Note
udf-compiling::.

To create a function, you must have the `INSERT' privilege for the
`mysql' database. This is necessary because *Note `CREATE FUNCTION':
create-function. adds a row to the `mysql.func' system table that
records the function's name, type, and shared library name. If you do
not have this table, you should run the *Note `mysql_upgrade':
mysql-upgrade. command to create it. See *Note mysql-upgrade::.

An active function is one that has been loaded with *Note `CREATE
FUNCTION': create-function. and not removed with *Note `DROP FUNCTION':
drop-function. All active functions are reloaded each time the server
starts, unless you start *Note `mysqld': mysqld. with the
`--skip-grant-tables' option. In this case, UDF initialization is
skipped and UDFs are unavailable.

For instructions on writing user-defined functions, see *Note
adding-udf::. For the UDF mechanism to work, functions must be written
in C or C++ (or another language that can use C calling conventions),
your operating system must support dynamic loading and you must have
compiled *Note `mysqld': mysqld. dynamically (not statically).

An `AGGREGATE' function works exactly like a native MySQL aggregate
(summary) function such as `SUM' or `COUNT()'. For `AGGREGATE' to work,
your `mysql.func' table must contain a `type' column. If your
`mysql.func' table does not have this column, you should run the *Note
`mysql_upgrade': mysql-upgrade. program to create it (see *Note
mysql-upgrade::).

*Note*:

To upgrade the shared library associated with a UDF, issue a *Note
`DROP FUNCTION': drop-function. statement, upgrade the shared library,
and then issue a *Note `CREATE FUNCTION': create-function. statement. If
you upgrade the shared library first and then use *Note `DROP
FUNCTION': drop-function, the server may crash.


File: manual.info,  Node: drop-function-udf,  Prev: create-function-udf,  Up: plugin-sql

13.7.3.2 `DROP FUNCTION' Syntax
...............................

     DROP FUNCTION FUNCTION_NAME

This statement drops the user-defined function (UDF) named
FUNCTION_NAME.

To drop a function, you must have the `DELETE' privilege for the
`mysql' database. This is because *Note `DROP FUNCTION': drop-function.
removes a row from the `mysql.func' system table that records the
function's name, type, and shared library name.

*Note*:

To upgrade the shared library associated with a UDF, issue a *Note
`DROP FUNCTION': drop-function. statement, upgrade the shared library,
and then issue a *Note `CREATE FUNCTION': create-function. statement. If
you upgrade the shared library first and then use *Note `DROP
FUNCTION': drop-function, the server may crash.

*Note `DROP FUNCTION': drop-function. is also used to drop stored
functions (see *Note drop-procedure::).


File: manual.info,  Node: set-option,  Next: show,  Prev: plugin-sql,  Up: sql-syntax-server-administration

13.7.4 `SET' Syntax
-------------------

     SET VARIABLE_ASSIGNMENT [, VARIABLE_ASSIGNMENT] ...

     VARIABLE_ASSIGNMENT:
           USER_VAR_NAME = EXPR
         | [GLOBAL | SESSION] SYSTEM_VAR_NAME = EXPR
         | [@@global. | @@session. | @@]SYSTEM_VAR_NAME = EXPR

The *Note `SET': set-option.  statement assigns values to different
types of variables that affect the operation of the server or your
client. Older versions of MySQL employed `SET OPTION', but this syntax
is deprecated in favor of *Note `SET': set-option. without `OPTION'.

This section describes use of *Note `SET': set-option. for assigning
values to variables. The *Note `SET': set-option.  statement can be
used to assign values to these types of variables:

   * System variables. See *Note server-system-variables::. System
     variables also can be set at server startup, as described in *Note
     using-system-variables::.

     User-defined variables. See *Note user-variables::.

   * Stored procedure and function parameters, and stored program local
     variables. See *Note stored-program-variables::.

Some variants of *Note `SET': set-option. syntax are used in other
contexts:

   * `SET CHARACTER SET' and `SET NAMES' assign values to character set
     and collation variables associated with the connection to the
     server.  `SET ONESHOT' is used for replication. These variants are
     described later in this section.

   * *Note `SET PASSWORD': set-password. assigns account passwords. See
     *Note set-password::.

   * *Note `SET TRANSACTION ISOLATION LEVEL': set-transaction. sets the
     isolation level for transaction processing. See *Note
     set-transaction::.

The following discussion shows the different *Note `SET': set-option.
syntaxes that you can use to set variables. The examples use the `='
assignment operator, but you can also use the `:=' assignment operator
for this purpose.

A user variable is written as `@VAR_NAME' and can be set as follows:

     SET @VAR_NAME = EXPR;

Many system variables are dynamic and can be changed while the server
runs by using the *Note `SET': set-option.  statement. For a list, see
*Note dynamic-system-variables::. To change a system variable with
*Note `SET': set-option, refer to it as VAR_NAME, optionally preceded
by a modifier:

   * To indicate explicitly that a variable is a global variable,
     precede its name by `GLOBAL' or `@@global.'. The `SUPER' privilege
     is required to set global variables.

   * To indicate explicitly that a variable is a session variable,
     precede its name by `SESSION', `@@session.', or `@@'.  Setting a
     session variable requires no special privilege, but a client can
     change only its own session variables, not those of any other
     client.

   * `LOCAL' and `@@local.' are synonyms for `SESSION' and `@@session.'.

   * If no modifier is present, *Note `SET': set-option.  changes the
     session variable.

A *Note `SET': set-option.  statement can contain multiple variable
assignments, separated by commas. For example, the statement can assign
values to a user-defined variable and a system variable. If you set
several system variables, the most recent `GLOBAL' or `SESSION'
modifier in the statement is used for following variables that have no
modifier specified.

Examples:

     SET sort_buffer_size=10000;
     SET @@local.sort_buffer_size=10000;
     SET GLOBAL sort_buffer_size=1000000, SESSION sort_buffer_size=1000000;
     SET @@sort_buffer_size=1000000;
     SET @@global.sort_buffer_size=1000000, @@local.sort_buffer_size=1000000;

The `@@VAR_NAME' syntax for system variables is supported for
compatibility with some other database systems.

If you change a session system variable, the value remains in effect
until your session ends or until you change the variable to a different
value. The change is not visible to other clients.

If you change a global system variable, the value is remembered and
used for new connections until the server restarts. (To make a global
system variable setting permanent, you should set it in an option
file.) The change is visible to any client that accesses that global
variable. However, the change affects the corresponding session
variable only for clients that connect after the change. The global
variable change does not affect the session variable for any client
that is currently connected (not even that of the client that issues the
*Note `SET GLOBAL': set-option.  statement).

To prevent incorrect usage, MySQL produces an error if you use *Note
`SET GLOBAL': set-option.  with a variable that can only be used with
*Note `SET SESSION': set-option.  or if you do not specify `GLOBAL' (or
`@@global.') when setting a global variable.

To set a `SESSION' variable to the `GLOBAL' value or a `GLOBAL' value
to the compiled-in MySQL default value, use the `DEFAULT' keyword. For
example, the following two statements are identical in setting the
session value of `max_join_size' to the global value:

     SET max_join_size=DEFAULT;
     SET @@session.max_join_size=@@global.max_join_size;

Not all system variables can be set to `DEFAULT'.  In such cases, use
of `DEFAULT' results in an error.

You can refer to the values of specific global or session system
variables in expressions by using one of the `@@'-modifiers. For
example, you can retrieve values in a *Note `SELECT': select. statement
like this:

     SELECT @@global.sql_mode, @@session.sql_mode, @@sql_mode;

When you refer to a system variable in an expression as `@@VAR_NAME'
(that is, when you do not specify `@@global.' or `@@session.'), MySQL
returns the session value if it exists and the global value otherwise.
(This differs from `SET @@VAR_NAME = VALUE', which always refers to the
session value.)

*Note*:

Some variables displayed by `SHOW VARIABLES' may not be available using
`SELECT @@VAR_NAME' syntax; an `Unknown system variable' occurs. As a
workaround in such cases, you can use `SHOW VARIABLES LIKE 'VAR_NAME''.

Suffixes for specifying a value multiplier can be used when setting a
variable at server startup, but not to set the value with *Note `SET':
set-option. at runtime. On the other hand, with *Note `SET':
set-option. you can assign a variable's value using an expression,
which is not true when you set a variable at server startup. For
example, the first of the following lines is legal at server startup,
but the second is not:

     shell> mysql --max_allowed_packet=16M
     shell> mysql --max_allowed_packet=16*1024*1024

Conversely, the second of the following lines is legal at runtime, but
the first is not:

     mysql> SET GLOBAL max_allowed_packet=16M;
     mysql> SET GLOBAL max_allowed_packet=16*1024*1024;

To display system variables names and values, use the *Note `SHOW
VARIABLES': show-variables. statement. (See *Note show-variables::.)

The following list describes *Note `SET': set-option. options that have
nonstandard syntax (that is, options that are not set with `NAME =
VALUE' syntax).

   * `CHARACTER SET {CHARSET_NAME | DEFAULT}'

     This maps all strings from and to the client with the given
     mapping. You can add new mappings by editing `sql/convert.cc' in
     the MySQL source distribution. `SET CHARACTER SET' sets three
     session system variables: `character_set_client' and
     `character_set_results' are set to the given character set, and
     `character_set_connection' to the value of
     `character_set_database'. See *Note charset-connection::.

     The default mapping can be restored by using the value `DEFAULT'.
     The default depends on the server configuration.

     `ucs2' cannot be used as a client character set, which means that
     it does not work for `SET CHARACTER SET'.

   * `NAMES {'CHARSET_NAME' [COLLATE 'COLLATION_NAME'] | DEFAULT}'

     `SET NAMES' sets the three session system variables
     `character_set_client', `character_set_connection', and
     `character_set_results' to the given character set. Setting
     `character_set_connection' to `charset_name' also sets
     `collation_connection' to the default collation for
     `charset_name'. The optional `COLLATE' clause may be used to
     specify a collation explicitly. See *Note charset-connection::.

     The default mapping can be restored by using a value of `DEFAULT'.
     The default depends on the server configuration.

     `ucs2' cannot be used as a client character set, which means that
     it does not work for `SET NAMES'.

   * `ONE_SHOT'

     This option is a modifier, not a variable. It is _only_ for
     internal use for replication: *Note `mysqlbinlog': mysqlbinlog.
     uses `SET ONE_SHOT' to modify temporarily the values of character
     set, collation, and time zone variables to reflect at rollforward
     what they were originally.  `ONE_SHOT' is for internal use only
     and is deprecated for MySQL 5.0 and up.

     `ONE_SHOT' is intended for use only with the permitted set of
     variables. With other variables, an error occurs:

          mysql> SET ONE_SHOT max_allowed_packet = 1;
          ERROR 1382 (HY000): The 'SET ONE_SHOT' syntax is reserved for purposes
          internal to the MySQL server

     If `ONE_SHOT' is used with the permitted variables, it changes the
     variables as requested, but only for the next non-*Note `SET':
     set-option.  statement. After that, the server resets all
     character set, collation, and time zone-related system variables
     to their previous values. Example:

          mysql> SET ONE_SHOT character_set_connection = latin5;

          mysql> SET ONE_SHOT collation_connection = latin5_turkish_ci;

          mysql> SHOW VARIABLES LIKE '%_connection';
          +--------------------------+-------------------+
          | Variable_name            | Value             |
          +--------------------------+-------------------+
          | character_set_connection | latin5            |
          | collation_connection     | latin5_turkish_ci |
          +--------------------------+-------------------+

          mysql> SHOW VARIABLES LIKE '%_connection';
          +--------------------------+-------------------+
          | Variable_name            | Value             |
          +--------------------------+-------------------+
          | character_set_connection | latin1            |
          | collation_connection     | latin1_swedish_ci |
          +--------------------------+-------------------+


File: manual.info,  Node: show,  Next: other-administrative-sql,  Prev: set-option,  Up: sql-syntax-server-administration

13.7.5 `SHOW' Syntax
--------------------

* Menu:

* show-binary-logs::             `SHOW BINARY LOGS' Syntax
* show-binlog-events::           `SHOW BINLOG EVENTS' Syntax
* show-character-set::           `SHOW CHARACTER SET' Syntax
* show-collation::               `SHOW COLLATION' Syntax
* show-columns::                 `SHOW COLUMNS' Syntax
* show-create-database::         `SHOW CREATE DATABASE' Syntax
* show-create-function::         `SHOW CREATE FUNCTION' Syntax
* show-create-procedure::        `SHOW CREATE PROCEDURE' Syntax
* show-create-table::            `SHOW CREATE TABLE' Syntax
* show-create-view::             `SHOW CREATE VIEW' Syntax
* show-databases::               `SHOW DATABASES' Syntax
* show-engine::                  `SHOW ENGINE' Syntax
* show-engines::                 `SHOW ENGINES' Syntax
* show-errors::                  `SHOW ERRORS' Syntax
* show-function-code::           `SHOW FUNCTION CODE' Syntax
* show-function-status::         `SHOW FUNCTION STATUS' Syntax
* show-grants::                  `SHOW GRANTS' Syntax
* show-index::                   `SHOW INDEX' Syntax
* show-innodb-status::           `SHOW INNODB STATUS' Syntax
* show-logs::                    `SHOW LOGS' Syntax
* show-master-status::           `SHOW MASTER STATUS' Syntax
* show-mutex-status::            `SHOW MUTEX STATUS' Syntax
* show-open-tables::             `SHOW OPEN TABLES' Syntax
* show-privileges::              `SHOW PRIVILEGES' Syntax
* show-procedure-code::          `SHOW PROCEDURE CODE' Syntax
* show-procedure-status::        `SHOW PROCEDURE STATUS' Syntax
* show-processlist::             `SHOW PROCESSLIST' Syntax
* show-profile::                 `SHOW PROFILE' Syntax
* show-profiles::                `SHOW PROFILES' Syntax
* show-slave-hosts::             `SHOW SLAVE HOSTS' Syntax
* show-slave-status::            `SHOW SLAVE STATUS' Syntax
* show-status::                  `SHOW STATUS' Syntax
* show-table-status::            `SHOW TABLE STATUS' Syntax
* show-tables::                  `SHOW TABLES' Syntax
* show-triggers::                `SHOW TRIGGERS' Syntax
* show-variables::               `SHOW VARIABLES' Syntax
* show-warnings::                `SHOW WARNINGS' Syntax

*Note `SHOW': show. has many forms that provide information about
databases, tables, columns, or status information about the server.
This section describes those following:

     SHOW {BINARY | MASTER} LOGS
     SHOW BINLOG EVENTS [IN 'LOG_NAME'] [FROM POS] [LIMIT [OFFSET,] ROW_COUNT]
     SHOW CHARACTER SET [LIKE_OR_WHERE]
     SHOW COLLATION [LIKE_OR_WHERE]
     SHOW [FULL] COLUMNS FROM TBL_NAME [FROM DB_NAME] [LIKE_OR_WHERE]
     SHOW CREATE DATABASE DB_NAME
     SHOW CREATE FUNCTION FUNC_NAME
     SHOW CREATE PROCEDURE PROC_NAME
     SHOW CREATE TABLE TBL_NAME
     SHOW DATABASES [LIKE_OR_WHERE]
     SHOW ENGINE ENGINE_NAME {LOGS | STATUS }
     SHOW [STORAGE] ENGINES
     SHOW ERRORS [LIMIT [OFFSET,] ROW_COUNT]
     SHOW FUNCTION CODE FUNC_NAME
     SHOW FUNCTION STATUS [LIKE_OR_WHERE]
     SHOW GRANTS FOR USER
     SHOW INDEX FROM TBL_NAME [FROM DB_NAME]
     SHOW INNODB STATUS
     SHOW PROCEDURE CODE PROC_NAME
     SHOW PROCEDURE STATUS [LIKE_OR_WHERE]
     SHOW [BDB] LOGS
     SHOW MASTER STATUS
     SHOW MUTEX STATUS
     SHOW OPEN TABLES [FROM DB_NAME] [LIKE_OR_WHERE]
     SHOW PRIVILEGES
     SHOW [FULL] PROCESSLIST
     SHOW SLAVE HOSTS
     SHOW SLAVE STATUS
     SHOW PROFILE [TYPES] [FOR QUERY N] [OFFSET N] [LIMIT N]
     SHOW PROFILES
     SHOW [GLOBAL | SESSION] STATUS [LIKE_OR_WHERE]
     SHOW TABLE STATUS [FROM DB_NAME] [LIKE_OR_WHERE]
     SHOW [FULL] TABLES [FROM DB_NAME] [LIKE_OR_WHERE]
     SHOW TRIGGERS [FROM DB_NAME] [LIKE_OR_WHERE]
     SHOW [GLOBAL | SESSION] VARIABLES [LIKE_OR_WHERE]
     SHOW WARNINGS [LIMIT [OFFSET,] ROW_COUNT]

     LIKE_OR_WHERE:
         LIKE 'PATTERN'
       | WHERE EXPR

If the syntax for a given *Note `SHOW': show.  statement includes a
`LIKE 'PATTERN'' part, `'PATTERN'' is a string that can contain the SQL
``%'' and ``_'' wildcard characters. The pattern is useful for
restricting statement output to matching values.

Several *Note `SHOW': show. statements also accept a `WHERE' clause
that provides more flexibility in specifying which rows to display. See
*Note extended-show::.

Many MySQL APIs (such as PHP) enable you to treat the result returned
from a *Note `SHOW': show. statement as you would a result set from a
*Note `SELECT': select.; see *Note connectors-apis::, or your API
documentation for more information. In addition, you can work in SQL
with results from queries on tables in the `INFORMATION_SCHEMA'
database, which you cannot easily do with results from *Note `SHOW':
show.  statements. See *Note information-schema::.


File: manual.info,  Node: show-binary-logs,  Next: show-binlog-events,  Prev: show,  Up: show

13.7.5.1 `SHOW BINARY LOGS' Syntax
..................................

     SHOW BINARY LOGS
     SHOW MASTER LOGS

Lists the binary log files on the server. This statement is used as
part of the procedure described in *Note purge-binary-logs::, that
shows how to determine which logs can be purged.

     mysql> SHOW BINARY LOGS;
     +---------------+-----------+
     | Log_name      | File_size |
     +---------------+-----------+
     | binlog.000015 |    724935 |
     | binlog.000016 |    733481 |
     +---------------+-----------+

*Note `SHOW MASTER LOGS': show-binary-logs. is equivalent to *Note
`SHOW BINARY LOGS': show-binary-logs. The `File_size' column is
displayed as of MySQL 5.0.7.


File: manual.info,  Node: show-binlog-events,  Next: show-character-set,  Prev: show-binary-logs,  Up: show

13.7.5.2 `SHOW BINLOG EVENTS' Syntax
....................................

     SHOW BINLOG EVENTS
        [IN 'LOG_NAME'] [FROM POS] [LIMIT [OFFSET,] ROW_COUNT]

Shows the events in the binary log. If you do not specify `'LOG_NAME'',
the first binary log is displayed.

The `LIMIT' clause has the same syntax as for the *Note `SELECT':
select. statement. See *Note select::.

*Note*:

Issuing a *Note `SHOW BINLOG EVENTS': show-binlog-events.  with no
`LIMIT' clause could start a very time- and resource-consuming process
because the server returns to the client the complete contents of the
binary log (which includes all statements executed by the server that
modify data). As an alternative to *Note `SHOW BINLOG EVENTS':
show-binlog-events, use the *Note `mysqlbinlog': mysqlbinlog. utility
to save the binary log to a text file for later examination and
analysis. See *Note mysqlbinlog::.

*Note*:

Some events relating to the setting of user and system variables are
not included in the output from *Note `SHOW BINLOG EVENTS':
show-binlog-events. To get complete coverage of events within a binary
log, use *Note `mysqlbinlog': mysqlbinlog.


File: manual.info,  Node: show-character-set,  Next: show-collation,  Prev: show-binlog-events,  Up: show

13.7.5.3 `SHOW CHARACTER SET' Syntax
....................................

     SHOW CHARACTER SET
         [LIKE 'PATTERN' | WHERE EXPR]

The *Note `SHOW CHARACTER SET': show-character-set. statement shows all
available character sets. The `LIKE' clause, if present, indicates
which character set names to match. The `WHERE' clause can be given to
select rows using more general conditions, as discussed in *Note
extended-show::. For example:

     mysql> SHOW CHARACTER SET LIKE 'latin%';
     +---------+-----------------------------+-------------------+--------+
     | Charset | Description                 | Default collation | Maxlen |
     +---------+-----------------------------+-------------------+--------+
     | latin1  | cp1252 West European        | latin1_swedish_ci |      1 |
     | latin2  | ISO 8859-2 Central European | latin2_general_ci |      1 |
     | latin5  | ISO 8859-9 Turkish          | latin5_turkish_ci |      1 |
     | latin7  | ISO 8859-13 Baltic          | latin7_general_ci |      1 |
     +---------+-----------------------------+-------------------+--------+

The `Maxlen' column shows the maximum number of bytes required to store
one character.


File: manual.info,  Node: show-collation,  Next: show-columns,  Prev: show-character-set,  Up: show

13.7.5.4 `SHOW COLLATION' Syntax
................................

     SHOW COLLATION
         [LIKE 'PATTERN' | WHERE EXPR]

This statement lists collations supported by the server. By default,
the output from *Note `SHOW COLLATION': show-collation. includes all
available collations. The `LIKE' clause, if present, indicates which
collation names to match. The `WHERE' clause can be given to select
rows using more general conditions, as discussed in *Note
extended-show::. For example:

     mysql> SHOW COLLATION LIKE 'latin1%';
     +-------------------+---------+----+---------+----------+---------+
     | Collation         | Charset | Id | Default | Compiled | Sortlen |
     +-------------------+---------+----+---------+----------+---------+
     | latin1_german1_ci | latin1  |  5 |         |          |       0 |
     | latin1_swedish_ci | latin1  |  8 | Yes     | Yes      |       0 |
     | latin1_danish_ci  | latin1  | 15 |         |          |       0 |
     | latin1_german2_ci | latin1  | 31 |         | Yes      |       2 |
     | latin1_bin        | latin1  | 47 |         | Yes      |       0 |
     | latin1_general_ci | latin1  | 48 |         |          |       0 |
     | latin1_general_cs | latin1  | 49 |         |          |       0 |
     | latin1_spanish_ci | latin1  | 94 |         |          |       0 |
     +-------------------+---------+----+---------+----------+---------+

The `Collation' and `Charset' columns indicate the names of the
collation and the character set with which it is associated. `Id' is the
collation ID. `Default' indicates whether the collation is the default
for its character set.  `Compiled' indicates whether the character set
is compiled into the server. `Sortlen' is related to the amount of
memory required to sort strings expressed in the character set.

To see the default collation for each character set, use the following
statement. `Default' is a reserved word, so to use it as an identifier,
it must be quoted as such:

     mysql> SHOW COLLATION WHERE `Default` = 'Yes';
     +---------------------+----------+----+---------+----------+---------+
     | Collation           | Charset  | Id | Default | Compiled | Sortlen |
     +---------------------+----------+----+---------+----------+---------+
     | big5_chinese_ci     | big5     |  1 | Yes     | Yes      |       1 |
     | dec8_swedish_ci     | dec8     |  3 | Yes     | Yes      |       1 |
     | cp850_general_ci    | cp850    |  4 | Yes     | Yes      |       1 |
     | hp8_english_ci      | hp8      |  6 | Yes     | Yes      |       1 |
     | koi8r_general_ci    | koi8r    |  7 | Yes     | Yes      |       1 |
     | latin1_swedish_ci   | latin1   |  8 | Yes     | Yes      |       1 |
     ...


File: manual.info,  Node: show-columns,  Next: show-create-database,  Prev: show-collation,  Up: show

13.7.5.5 `SHOW COLUMNS' Syntax
..............................

     SHOW [FULL] COLUMNS {FROM | IN} TBL_NAME [{FROM | IN} DB_NAME]
         [LIKE 'PATTERN' | WHERE EXPR]

*Note `SHOW COLUMNS': show-columns. displays information about the
columns in a given table. It also works for views as of MySQL 5.0.1.
The `LIKE' clause, if present, indicates which column names to match.
The `WHERE' clause can be given to select rows using more general
conditions, as discussed in *Note extended-show::.

     mysql> SHOW COLUMNS FROM City;
     +------------+----------+------+-----+---------+----------------+
     | Field      | Type     | Null | Key | Default | Extra          |
     +------------+----------+------+-----+---------+----------------+
     | Id         | int(11)  | NO   | PRI | NULL    | auto_increment |
     | Name       | char(35) | NO   |     |         |                |
     | Country    | char(3)  | NO   | UNI |         |                |
     | District   | char(20) | YES  | MUL |         |                |
     | Population | int(11)  | NO   |     | 0       |                |
     +------------+----------+------+-----+---------+----------------+
     5 rows in set (0.00 sec)

If the data types differ from what you expect them to be based on a
*Note `CREATE TABLE': create-table. statement, note that MySQL
sometimes changes data types when you create or alter a table. The
conditions under which this occurs are described in *Note
silent-column-changes::.

The `FULL' keyword causes the output to include the column collation
and comments, as well as the privileges you have for each column.

You can use DB_NAME.TBL_NAME as an alternative to the `TBL_NAME FROM
DB_NAME' syntax. In other words, these two statements are equivalent:

     mysql> SHOW COLUMNS FROM mytable FROM mydb;
     mysql> SHOW COLUMNS FROM mydb.mytable;

*Note `SHOW COLUMNS': show-columns. displays the following values for
each table column:

`Field' indicates the column name.

`Type' indicates the column data type.

`Collation' indicates the collation for nonbinary string columns, or
`NULL' for other columns. This value is displayed only if you use the
`FULL' keyword.

The `Null' field contains `YES' if `NULL' values can be stored in the
column. If not, the column contains `NO' as of MySQL 5.0.3, and `'''
before that.

The `Key' field indicates whether the column is indexed:

   * If `Key' is empty, the column either is not indexed or is indexed
     only as a secondary column in a multiple-column, nonunique index.

   * If `Key' is `PRI', the column is a `PRIMARY KEY' or is one of the
     columns in a multiple-column `PRIMARY KEY'.

   * If `Key' is `UNI', the column is the first column of a
     unique-valued index that cannot contain `NULL' values.

   * If `Key' is `MUL', multiple occurrences of a given value are
     permitted within the column. The column is the first column of a
     nonunique index or a unique-valued index that can contain `NULL'
     values.

If more than one of the `Key' values applies to a given column of a
table, `Key' displays the one with the highest priority, in the order
`PRI', `UNI', `MUL'.

A `UNIQUE' index may be displayed as `PRI' if it cannot contain `NULL'
values and there is no `PRIMARY KEY' in the table. A `UNIQUE' index may
display as `MUL' if several columns form a composite `UNIQUE' index;
although the combination of the columns is unique, each column can
still hold multiple occurrences of a given value.

Before MySQL 5.0.11, if the column permits `NULL' values, the `Key'
value can be `MUL' even when a single-column `UNIQUE' index is used.
The rationale was that multiple rows in a `UNIQUE' index can hold a
`NULL' value if the column is not declared `NOT NULL'. As of MySQL
5.0.11, the display is `UNI' rather than `MUL' regardless of whether
the column permits `NULL'; you can see from the `Null' field whether or
not the column can contain `NULL'.

The `Default' field indicates the default value that is assigned to the
column.

The `Extra' field contains any additional information that is available
about a given column. The value is `auto_increment' for columns that
have the `AUTO_INCREMENT' attribute and empty otherwise.

`Privileges' indicates the privileges you have for the column. This
value is displayed only if you use the `FULL' keyword.

`Comment' indicates any comment the column has.  This value is
displayed only if you use the `FULL' keyword.

`SHOW FIELDS' is a synonym for *Note `SHOW COLUMNS': show-columns. You
can also list a table's columns with the *Note `mysqlshow DB_NAME
TBL_NAME': mysqlshow. command.

The *Note `DESCRIBE': describe. statement provides information similar
to *Note `SHOW COLUMNS': show-columns. See *Note describe::.

The *Note `SHOW CREATE TABLE': show-create-table, *Note `SHOW TABLE
STATUS': show-table-status, and *Note `SHOW INDEX': show-index.
statements also provide information about tables. See *Note show::.


File: manual.info,  Node: show-create-database,  Next: show-create-function,  Prev: show-columns,  Up: show

13.7.5.6 `SHOW CREATE DATABASE' Syntax
......................................

     SHOW CREATE {DATABASE | SCHEMA} DB_NAME

Shows the *Note `CREATE DATABASE': create-database.  statement that
creates the given database.  *Note `SHOW CREATE SCHEMA':
show-create-database. is a synonym for *Note `SHOW CREATE DATABASE':
show-create-database. as of MySQL 5.0.2.

     mysql> SHOW CREATE DATABASE test\G
     *************************** 1. row ***************************
            Database: test
     Create Database: CREATE DATABASE `test`
                      /*!40100 DEFAULT CHARACTER SET latin1 */

     mysql> SHOW CREATE SCHEMA test\G
     *************************** 1. row ***************************
            Database: test
     Create Database: CREATE DATABASE `test`
                      /*!40100 DEFAULT CHARACTER SET latin1 */

*Note `SHOW CREATE DATABASE': show-create-database. quotes table and
column names according to the value of the `sql_quote_show_create'
option.  See *Note server-system-variables::.


File: manual.info,  Node: show-create-function,  Next: show-create-procedure,  Prev: show-create-database,  Up: show

13.7.5.7 `SHOW CREATE FUNCTION' Syntax
......................................

     SHOW CREATE FUNCTION FUNC_NAME

This statement is similar to *Note `SHOW CREATE PROCEDURE':
show-create-procedure. but for stored functions. See *Note
show-create-procedure::.


File: manual.info,  Node: show-create-procedure,  Next: show-create-table,  Prev: show-create-function,  Up: show

13.7.5.8 `SHOW CREATE PROCEDURE' Syntax
.......................................

     SHOW CREATE PROCEDURE PROC_NAME

This statement is a MySQL extension. It returns the exact string that
can be used to re-create the named stored procedure. A similar
statement, *Note `SHOW CREATE FUNCTION': show-create-function, displays
information about stored functions (see *Note show-create-function::).

Both statements require that you be the owner of the routine or have
*Note `SELECT': select. access to the `mysql.proc' table. If you do not
have privileges for the routine itself, the value displayed for the
`Create Procedure' or `Create Function' field will be `NULL'.

     mysql> SHOW CREATE PROCEDURE test.simpleproc\G
     *************************** 1. row ***************************
            Procedure: simpleproc
             sql_mode:
     Create Procedure: CREATE PROCEDURE `simpleproc`(OUT param1 INT)
                       BEGIN
                       SELECT COUNT(*) INTO param1 FROM t;
                       END

     mysql> SHOW CREATE FUNCTION test.hello\G
     *************************** 1. row ***************************
            Function: hello
            sql_mode:
     Create Function: CREATE FUNCTION `hello`(s CHAR(20))
                      RETURNS CHAR(50)
                      RETURN CONCAT('Hello, ',s,'!')


File: manual.info,  Node: show-create-table,  Next: show-create-view,  Prev: show-create-procedure,  Up: show

13.7.5.9 `SHOW CREATE TABLE' Syntax
...................................

     SHOW CREATE TABLE TBL_NAME

Shows the *Note `CREATE TABLE': create-table. statement that creates
the given table. The statement requires the `SELECT' privilege for the
table.  As of MySQL 5.0.1, this statement also works with views.

     mysql> SHOW CREATE TABLE t\G
     *************************** 1. row ***************************
            Table: t
     Create Table: CREATE TABLE t (
       id INT(11) default NULL auto_increment,
       s char(60) default NULL,
       PRIMARY KEY (id)
     ) ENGINE=MyISAM

*Note `SHOW CREATE TABLE': show-create-table. quotes table and column
names according to the value of the `sql_quote_show_create' option.
See *Note server-system-variables::.


File: manual.info,  Node: show-create-view,  Next: show-databases,  Prev: show-create-table,  Up: show

13.7.5.10 `SHOW CREATE VIEW' Syntax
...................................

     SHOW CREATE VIEW VIEW_NAME

This statement shows a *Note `CREATE VIEW': create-view. statement that
creates the given view.

     mysql> SHOW CREATE VIEW v;
     +------+----------------------------------------------------+
     | View | Create View                                        |
     +------+----------------------------------------------------+
     | v    | CREATE VIEW `test`.`v` AS select 1 AS `a`,2 AS `b` |
     +------+----------------------------------------------------+

This statement was added in MySQL 5.0.1.

Prior to MySQL 5.0.11, the output columns from this statement were
shown as `Table' and `Create Table'.

Use of *Note `SHOW CREATE VIEW': show-create-view. requires the `SHOW
VIEW' privilege and the `SELECT' privilege for the view in question.

You can also obtain information about view objects from
`INFORMATION_SCHEMA', which contains a *Note `VIEWS': views-table.
table. See *Note views-table::.

MySQL lets you use different `sql_mode' settings to tell the server the
type of SQL syntax to support. For example, you might use the `ANSI'
SQL mode to ensure MySQL correctly interprets the standard SQL
concatenation operator, the double bar (`||'), in your queries. If you
then create a view that concatenates items, you might worry that
changing the `sql_mode' setting to a value different from `ANSI' could
cause the view to become invalid. But this is not the case. No matter
how you write out a view definition, MySQL always stores it the same
way, in a canonical form. Here is an example that shows how the server
changes a double bar concatenation operator to a `CONCAT()' function:

     mysql> SET sql_mode = 'ANSI';
     Query OK, 0 rows affected (0.00 sec)

     mysql> CREATE VIEW test.v AS SELECT 'a' || 'b' as col1;
     Query OK, 0 rows affected (0.01 sec)

     mysql> SHOW CREATE VIEW test.v\G
     *************************** 1. row ***************************
                     View: v
              Create View: CREATE VIEW "v" AS select concat('a','b') AS "col1"
     ...
     1 row in set (0.00 sec)

The advantage of storing a view definition in canonical form is that
changes made later to the value of `sql_mode' will not affect the
results from the view. However an additional consequence is that
comments prior to *Note `SELECT': select. are stripped from the
definition by the server.


File: manual.info,  Node: show-databases,  Next: show-engine,  Prev: show-create-view,  Up: show

13.7.5.11 `SHOW DATABASES' Syntax
.................................

     SHOW {DATABASES | SCHEMAS}
         [LIKE 'PATTERN' | WHERE EXPR]

*Note `SHOW DATABASES': show-databases. lists the databases on the
MySQL server host.  *Note `SHOW SCHEMAS': show-databases. is a synonym
for *Note `SHOW DATABASES': show-databases. as of MySQL 5.0.2. The
`LIKE' clause, if present, indicates which database names to match. The
`WHERE' clause can be given to select rows using more general
conditions, as discussed in *Note extended-show::.

You see only those databases for which you have some kind of privilege,
unless you have the global *Note `SHOW DATABASES': show-databases.
privilege. You can also get this list using the *Note `mysqlshow':
mysqlshow. command.

If the server was started with the `--skip-show-database' option, you
cannot use this statement at all unless you have the `SHOW DATABASES'
privilege.

MySQL implements databases as directories in the data directory, so
this statement simply lists directories in that location.  However, the
output may include names of directories that do not correspond to
actual databases.


File: manual.info,  Node: show-engine,  Next: show-engines,  Prev: show-databases,  Up: show

13.7.5.12 `SHOW ENGINE' Syntax
..............................

     SHOW ENGINE ENGINE_NAME {LOGS | STATUS }

*Note `SHOW ENGINE': show-engine. displays log or status information
about a storage engine. The following statements currently are
supported:

     SHOW ENGINE BDB LOGS
     SHOW ENGINE INNODB STATUS
     SHOW ENGINE NDB STATUS
     SHOW ENGINE NDBCLUSTER STATUS

*Note `SHOW ENGINE BDB LOGS': show-engine. displays status information
about existing `BDB' log files. It returns the following fields:

   * `File'

     The full path to the log file.

   * `Type'

     The log file type (`BDB' for Berkeley DB log files).

   * `Status'

     The status of the log file (`FREE' if the file can be removed, or
     `IN USE' if the file is needed by the transaction subsystem)

*Note `SHOW ENGINE INNODB STATUS': show-engine. displays extensive
information from the standard `InnoDB' Monitor about the state of the
`InnoDB' storage engine. For information about the standard monitor and
other `InnoDB' Monitors that provide information about `InnoDB'
processing, see *Note innodb-monitors::.

Older (and now deprecated) synonyms for *Note `SHOW ENGINE BDB LOGS':
show-engine. and *Note `SHOW ENGINE INNODB STATUS': show-engine. are
`SHOW [BDB] LOGS' and *Note `SHOW INNODB STATUS': show-innodb-status,
respectively.

If the server has the *Note `NDBCLUSTER': mysql-cluster.  storage
engine enabled, *Note `SHOW ENGINE NDB STATUS': show-engine. can be
used to display cluster status information. Sample output from this
statement is shown here:

     mysql> SHOW ENGINE NDB STATUS;
     +-----------------------+---------+------+--------+
     | free_list             | created | free | sizeof |
     +-----------------------+---------+------+--------+
     | NdbTransaction        |       5 |    0 |    208 |
     | NdbOperation          |       4 |    4 |    660 |
     | NdbIndexScanOperation |       1 |    1 |    736 |
     | NdbIndexOperation     |       0 |    0 |   1060 |
     | NdbRecAttr            |     645 |  645 |     72 |
     | NdbApiSignal          |      16 |   16 |    136 |
     | NdbLabel              |       0 |    0 |    196 |
     | NdbBranch             |       0 |    0 |     24 |
     | NdbSubroutine         |       0 |    0 |     68 |
     | NdbCall               |       0 |    0 |     16 |
     | NdbBlob               |       2 |    2 |    204 |
     | NdbReceiver           |       2 |    0 |     68 |
     +-----------------------+---------+------+--------+
     12 rows in set (0.00 sec)

The most useful of the rows from the output of this statement are
described in the following list:

   * `NdbTransaction': The number and size of `NdbTransaction' objects
     that have been created. An `NdbTransaction' is created each time a
     table schema operation (such as *Note `CREATE TABLE':
     create-table. or *Note `ALTER TABLE': alter-table.) is performed on
     an *Note `NDB': mysql-cluster. table.

   * `NdbOperation': The number and size of `NdbOperation' objects that
     have been created.

   * `NdbIndexScanOperation': The number and size of
     `NdbIndexScanOperation' objects that have been created.

   * `NdbIndexOperation': The number and size of `NdbIndexOperation'
     objects that have been created.

   * `NdbRecAttr': The number and size of `NdbRecAttr' objects that
     have been created. In general, one of these is created each time a
     data manipulation statement is performed by an SQL node.

   * `NdbBlob': The number and size of `NdbBlob' objects that have been
     created.  An `NdbBlob' is created for each new operation involving
     a *Note `BLOB': blob.  column in an *Note `NDB': mysql-cluster.
     table.

   * `NdbReceiver': The number and size of any `NdbReceiver' object
     that have been created. The number in the `created' column is the
     same as the number of data nodes in the cluster to which the MySQL
     server has connected.

*Note*:

*Note `SHOW ENGINE NDB STATUS': show-engine. returns an empty result if
no operations involving *Note `NDB': mysql-cluster. tables have been
performed by the MySQL client accessing the SQL node on which this
statement is run.

*Note `SHOW ENGINE NDBCLUSTER STATUS': show-engine. is a synonym for
*Note `SHOW ENGINE NDB STATUS': show-engine.


File: manual.info,  Node: show-engines,  Next: show-errors,  Prev: show-engine,  Up: show

13.7.5.13 `SHOW ENGINES' Syntax
...............................

     SHOW [STORAGE] ENGINES

*Note `SHOW ENGINES': show-engines. displays status information about
the server's storage engines. This is particularly useful for checking
whether a storage engine is supported, or to see what the default
engine is. `SHOW TABLE TYPES' is a synonym, but is deprecated and is
removed in MySQL 5.5.

     mysql> SHOW ENGINES\G
     *************************** 1. row ***************************
      Engine: MyISAM
     Support: DEFAULT
     Comment: Default engine as of MySQL 3.23 with great performance
     *************************** 2. row ***************************
      Engine: MEMORY
     Support: YES
     Comment: Hash based, stored in memory, useful for temporary tables
     *************************** 3. row ***************************
      Engine: HEAP
     Support: YES
     Comment: Alias for MEMORY
     *************************** 4. row ***************************
      Engine: MERGE
     Support: YES
     Comment: Collection of identical MyISAM tables
     *************************** 5. row ***************************
      Engine: MRG_MYISAM
     Support: YES
     Comment: Alias for MERGE
     *************************** 6. row ***************************
      Engine: ISAM
     Support: NO
     Comment: Obsolete storage engine, now replaced by MyISAM
     *************************** 7. row ***************************
      Engine: MRG_ISAM
     Support: NO
     Comment: Obsolete storage engine, now replaced by MERGE
     *************************** 8. row ***************************
      Engine: InnoDB
     Support: YES
     Comment: Supports transactions, row-level locking, and foreign keys
     *************************** 9. row ***************************
      Engine: INNOBASE
     Support: YES
     Comment: Alias for INNODB
     *************************** 10. row ***************************
      Engine: BDB
     Support: YES
     Comment: Supports transactions and page-level locking
     *************************** 11. row ***************************
      Engine: BERKELEYDB
     Support: YES
     Comment: Alias for BDB
     *************************** 12. row ***************************
      Engine: NDBCLUSTER
     Support: NO
     Comment: Clustered, fault-tolerant, memory-based tables
     *************************** 13. row ***************************
      Engine: NDB
     Support: NO
     Comment: Alias for NDBCLUSTER
     *************************** 14. row ***************************
      Engine: EXAMPLE
     Support: NO
     Comment: Example storage engine
     *************************** 15. row ***************************
      Engine: ARCHIVE
     Support: YES
     Comment: Archive storage engine
     *************************** 16. row ***************************
      Engine: CSV
     Support: NO
     Comment: CSV storage engine
     *************************** 17. row ***************************
      Engine: FEDERATED
     Support: YES
     Comment: Federated MySQL storage engine
     *************************** 18. row ***************************
      Engine: BLACKHOLE
     Support: YES
     Comment: /dev/null storage engine (anything you write to it disappears)

The output from *Note `SHOW ENGINES': show-engines. may vary according
to the MySQL version used and other factors. The values shown in the
`Support' column indicate the server's level of support for the storage
engine, as shown in the following table.

Value       Meaning
`YES'       The engine is supported and is active
`DEFAULT'   Like `YES', plus this is the default engine
`NO'        The engine is not supported
`DISABLED'  The engine is supported but has been disabled

A value of `NO' means that the server was compiled without support for
the engine, so it cannot be activated at runtime.

A value of `DISABLED' occurs either because the server was started with
an option that disables the engine, or because not all options required
to enable it were given. In the latter case, the error log file should
contain a reason indicating why the option is disabled. See *Note
error-log::.

You might also see `DISABLED' for a storage engine if the server was
compiled to support it, but was started with a `--skip-ENGINE_NAME'
option. For example, `--skip-innodb' disables the `InnoDB' engine. For
the *Note `NDBCLUSTER': mysql-cluster. storage engine, `DISABLED' means
the server was compiled with support for MySQL Cluster, but was not
started with the `--ndbcluster' option.

All MySQL servers support `MyISAM' tables, because `MyISAM' is the
default storage engine.  It is not possible to disable `MyISAM'.


File: manual.info,  Node: show-errors,  Next: show-function-code,  Prev: show-engines,  Up: show

13.7.5.14 `SHOW ERRORS' Syntax
..............................

     SHOW ERRORS [LIMIT [OFFSET,] ROW_COUNT]
     SHOW COUNT(*) ERRORS

This statement is similar to *Note `SHOW WARNINGS': show-warnings,
except that it displays information only for errors, rather than for
errors, warnings, and notes.

The `LIMIT' clause has the same syntax as for the *Note `SELECT':
select. statement. See *Note select::.

The *Note `SHOW COUNT(*) ERRORS': show-errors. statement displays the
number of errors. You can also retrieve this number from the
`error_count' variable:

     SHOW COUNT(*) ERRORS;
     SELECT @@error_count;

*Note `SHOW ERRORS': show-errors. and `error_count' apply only to
errors, not warnings or notes. In other respects, they are similar to
*Note `SHOW WARNINGS': show-warnings. and `warning_count'. In
particular, *Note `SHOW ERRORS': show-errors. cannot display
information for more than `max_error_count' messages, and `error_count'
can exceed the value of `max_error_count' if the number of errors
exceeds `max_error_count'.

For more information, see *Note show-warnings::.


File: manual.info,  Node: show-function-code,  Next: show-function-status,  Prev: show-errors,  Up: show

13.7.5.15 `SHOW FUNCTION CODE' Syntax
.....................................

     SHOW FUNCTION CODE FUNC_NAME

This statement is similar to *Note `SHOW PROCEDURE CODE':
show-procedure-code. but for stored functions. See *Note
show-procedure-code::. *Note `SHOW FUNCTION CODE': show-function-code.
was added in MySQL 5.0.17.


File: manual.info,  Node: show-function-status,  Next: show-grants,  Prev: show-function-code,  Up: show

13.7.5.16 `SHOW FUNCTION STATUS' Syntax
.......................................

     SHOW FUNCTION STATUS
         [LIKE 'PATTERN' | WHERE EXPR]

This statement is similar to *Note `SHOW PROCEDURE STATUS':
show-procedure-status. but for stored functions. See *Note
show-procedure-status::.


File: manual.info,  Node: show-grants,  Next: show-index,  Prev: show-function-status,  Up: show

13.7.5.17 `SHOW GRANTS' Syntax
..............................

     SHOW GRANTS [FOR USER]

This statement lists the *Note `GRANT': grant.  statement or statements
that must be issued to duplicate the privileges that are granted to a
MySQL user account. The account is named using the same format as for
the *Note `GRANT': grant. statement; for example,
`'jeffrey'@'localhost''. If you specify only the user name part of the
account name, a host name part of `'%'' is used. For additional
information about specifying account names, see *Note grant::.

     mysql> SHOW GRANTS FOR 'root'@'localhost';
     +---------------------------------------------------------------------+
     | Grants for root@localhost                                           |
     +---------------------------------------------------------------------+
     | GRANT ALL PRIVILEGES ON *.* TO 'root'@'localhost' WITH GRANT OPTION |
     +---------------------------------------------------------------------+

To list the privileges granted to the account that you are using to
connect to the server, you can use any of the following statements:

     SHOW GRANTS;
     SHOW GRANTS FOR CURRENT_USER;
     SHOW GRANTS FOR CURRENT_USER();

As of MySQL 5.0.24, if `SHOW GRANTS FOR CURRENT_USER' (or any of the
equivalent syntaxes) is used in `DEFINER' context, such as within a
stored procedure that is defined with `SQL SECURITY DEFINER'), the
grants displayed are those of the definer and not the invoker.

*Note `SHOW GRANTS': show-grants. displays only the privileges granted
explicitly to the named account. Other privileges might be available to
the account, but they are not displayed. For example, if an anonymous
account exists, the named account might be able to use its privileges,
but *Note `SHOW GRANTS': show-grants. will not display them.

*Note `SHOW GRANTS': show-grants. requires the `SELECT' privilege for
the `mysql' database.


File: manual.info,  Node: show-index,  Next: show-innodb-status,  Prev: show-grants,  Up: show

13.7.5.18 `SHOW INDEX' Syntax
.............................

     SHOW {INDEX | INDEXES | KEYS}
         {FROM | IN} TBL_NAME
         [{FROM | IN} DB_NAME]
         [WHERE EXPR]

*Note `SHOW INDEX': show-index. returns table index information. The
format resembles that of the `SQLStatistics' call in ODBC.

*Note `SHOW INDEX': show-index. returns the following fields:

   * `Table'

     The name of the table.

   * `Non_unique'

     0 if the index cannot contain duplicates, 1 if it can.

   * `Key_name'

     The name of the index. If the index is the primary key, the name
     is always `PRIMARY'.

   * `Seq_in_index'

     The column sequence number in the index, starting with 1.

   * `Column_name'

     The column name.

   * `Collation'

     How the column is sorted in the index. In MySQL, this can have
     values ``A'' (Ascending) or `NULL' (Not sorted).

   * `Cardinality'

     An estimate of the number of unique values in the index.  This is
     updated by running *Note `ANALYZE TABLE': analyze-table. or *Note
     `myisamchk -a': myisamchk.  `Cardinality' is counted based on
     statistics stored as integers, so the value is not necessarily
     exact even for small tables. The higher the cardinality, the
     greater the chance that MySQL uses the index when doing joins.

   * `Sub_part'

     The number of indexed characters if the column is only partly
     indexed, `NULL' if the entire column is indexed.

   * `Packed'

     Indicates how the key is packed. `NULL' if it is not.

   * `Null'

     Contains `YES' if the column may contain `NULL' values and `''' if
     not.

   * `Index_type'

     The index method used (`BTREE', `FULLTEXT', `HASH', `RTREE').

   * `Comment'

     Information about the index not described in its own column, such
     as `disabled' if the index is disabled.

You can use DB_NAME.TBL_NAME as an alternative to the `TBL_NAME FROM
DB_NAME' syntax. These two statements are equivalent:

     SHOW INDEX FROM mytable FROM mydb;
     SHOW INDEX FROM mydb.mytable;

The `WHERE' clause can be given to select rows using more general
conditions, as discussed in *Note extended-show::.

You can also list a table's indexes with the *Note `mysqlshow -k
DB_NAME TBL_NAME': mysqlshow. command.


File: manual.info,  Node: show-innodb-status,  Next: show-logs,  Prev: show-index,  Up: show

13.7.5.19 `SHOW INNODB STATUS' Syntax
.....................................

     SHOW INNODB STATUS

In MySQL 5.0, this is a deprecated synonym for *Note `SHOW ENGINE
INNODB STATUS': show-engine. See *Note show-engine::.  *Note `SHOW
INNODB STATUS': show-innodb-status. is removed in MySQL 5.5.


File: manual.info,  Node: show-logs,  Next: show-master-status,  Prev: show-innodb-status,  Up: show

13.7.5.20 `SHOW LOGS' Syntax
............................

     SHOW [BDB] LOGS

In MySQL 5.0, this is a deprecated synonym for *Note `SHOW ENGINE BDB
LOGS': show-engine. See *Note show-engine::.


File: manual.info,  Node: show-master-status,  Next: show-mutex-status,  Prev: show-logs,  Up: show

13.7.5.21 `SHOW MASTER STATUS' Syntax
.....................................

     SHOW MASTER STATUS

This statement provides status information about the binary log files
of the master. It requires either the `SUPER' or `REPLICATION CLIENT'
privilege.

Example:

     mysql> SHOW MASTER STATUS;
     +---------------+----------+--------------+------------------+
     | File          | Position | Binlog_Do_DB | Binlog_Ignore_DB |
     +---------------+----------+--------------+------------------+
     | mysql-bin.003 | 73       | test         | manual,mysql     |
     +---------------+----------+--------------+------------------+


File: manual.info,  Node: show-mutex-status,  Next: show-open-tables,  Prev: show-master-status,  Up: show

13.7.5.22 `SHOW MUTEX STATUS' Syntax
....................................

     SHOW MUTEX STATUS

`SHOW MUTEX STATUS' displays `InnoDB' mutex statistics. From MySQL
5.0.3 to 5.0.32, the statement displays the following output fields:

   * `Mutex'

     The mutex name. The name indicates the mutex purpose. For example,
     the `log_sys' mutex is used by the `InnoDB' logging subsystem and
     indicates how intensive logging activity is. The `buf_pool' mutex
     protects the `InnoDB' buffer pool.

   * `Module'

     The source file where the mutex is implemented.

   * `Count' indicates how many times the mutex was requested.

   * `Spin_waits' indicates how many times the spinlock had to run.

   * `Spin_rounds' indicates the number of spinlock rounds.
     (`spin_rounds' divided by `spin_waits' provides the average round
     count.)

   * `OS_waits' indicates the number of operating system waits. This
     occurs when the spinlock did not work (the mutex was not locked
     during the spinlock and it was necessary to yield to the operating
     system and wait).

   * `OS_yields' indicates the number of times that a thread trying to
     lock a mutex gave up its timeslice and yielded to the operating
     system (on the presumption that permitting other threads to run
     will free the mutex so that it can be locked).

   * `OS_waits_time' indicates the amount of time (in ms) spent in
     operating system waits, if the `timed_mutexes' system variable is
     1 (`ON'). If `timed_mutexes' is 0 (`OFF'), timing is disabled, so
     `OS_waits_time' is 0.  `timed_mutexes' is off by default.

From MySQL 5.0.33 on, the statement uses the same output format as that
just described, but only if `UNIV_DEBUG' was defined at MySQL
compilation time (for example, in `include/univ.i' in the `InnoDB' part
of the MySQL source tree). If `UNIV_DEBUG' was not defined, the
statement displays the following fields. In the latter case (without
`UNIV_DEBUG'), the information on which the statement output is based
is insufficient to distinguish regular mutexes and mutexes that protect
rw-locks (which permit multiple readers or a single writer).
Consequently, the output may appear to contain multiple rows for the
same mutex.

   * `File'

     The source file where the mutex is implemented.

   * `Line'

     The line number in the source file where the mutex is created.
     This may change depending on your version of MySQL.

   * `OS_waits'

     Same as `OS_waits_time'.

Information from this statement can be used to diagnose system
problems. For example, large values of `spin_waits' and `spin_rounds'
may indicate scalability problems.

`SHOW MUTEX STATUS' was added in MySQL 5.0.3.  In MySQL 5.1, `SHOW
MUTEX STATUS' is deprecated and *Note `SHOW ENGINE INNODB MUTEX':
show-engine. should be used instead. The latter statement displays
similar information but in a somewhat different output format. *Note
`SHOW MUTEX STATUS': show-mutex-status. is removed in MySQL 5.5.


File: manual.info,  Node: show-open-tables,  Next: show-privileges,  Prev: show-mutex-status,  Up: show

13.7.5.23 `SHOW OPEN TABLES' Syntax
...................................

     SHOW OPEN TABLES [{FROM | IN} DB_NAME]
         [LIKE 'PATTERN' | WHERE EXPR]

*Note `SHOW OPEN TABLES': show-open-tables. lists the non-`TEMPORARY'
tables that are currently open in the table cache. See *Note
table-cache::. The `WHERE' clause can be given to select rows using
more general conditions, as discussed in *Note extended-show::.

The `FROM' and `LIKE' clauses may be used as of MySQL 5.0.12. The
`LIKE' clause, if present, indicates which table names to match. The
`FROM' clause, if present, restricts the tables shown to those present
in the DB_NAME database.

*Note `SHOW OPEN TABLES': show-open-tables. returns the following
columns:

   * `Database'

     The database containing the table.

   * `Table'

     The table name.

   * `In_use'

     The number of table locks or lock requests there are for the
     table. For example, if one client acquires a lock for a table
     using `LOCK TABLE t1 WRITE', `In_use' will be 1. If another client
     issues `LOCK TABLE t1 WRITE' while the table remains locked, the
     client will block waiting for the lock, but the lock request
     causes `In_use' to be 2. If the count is zero, the table is open
     but not currently being used. `In_use' is also increased by the
     *Note `HANDLER ... OPEN': handler. statement and decreased by
     *Note `HANDLER ... CLOSE': handler.

   * `Name_locked'

     Whether the table name is locked. Name locking is used for
     operations such as dropping or renaming tables.


File: manual.info,  Node: show-privileges,  Next: show-procedure-code,  Prev: show-open-tables,  Up: show

13.7.5.24 `SHOW PRIVILEGES' Syntax
..................................

     SHOW PRIVILEGES

*Note `SHOW PRIVILEGES': show-privileges. shows the list of system
privileges that the MySQL server supports. The exact list of privileges
depends on the version of your server.

     mysql> SHOW PRIVILEGES\G
     *************************** 1. row ***************************
     Privilege: Alter
     Context: Tables
     Comment: To alter the table
     *************************** 2. row ***************************
     Privilege: Alter routine
     Context: Functions,Procedures
     Comment: To alter or drop stored functions/procedures
     *************************** 3. row ***************************
     Privilege: Create
     Context: Databases,Tables,Indexes
     Comment: To create new databases and tables
     *************************** 4. row ***************************
     Privilege: Create routine
     Context: Functions,Procedures
     Comment: To use CREATE FUNCTION/PROCEDURE
     *************************** 5. row ***************************
     Privilege: Create temporary tables
     Context: Databases
     Comment: To use CREATE TEMPORARY TABLE
     ...

Privileges belonging to a specific user are displayed by the *Note
`SHOW GRANTS': show-grants. statement. See *Note show-grants::, for
more information.


File: manual.info,  Node: show-procedure-code,  Next: show-procedure-status,  Prev: show-privileges,  Up: show

13.7.5.25 `SHOW PROCEDURE CODE' Syntax
......................................

     SHOW PROCEDURE CODE PROC_NAME

This statement is a MySQL extension that is available only for servers
that have been built with debugging support. It displays a
representation of the internal implementation of the named stored
procedure. A similar statement, *Note `SHOW FUNCTION CODE':
show-function-code, displays information about stored functions (see
*Note show-function-code::).

Both statements require that you be the owner of the routine or have
*Note `SELECT': select. access to the `mysql.proc' table.

If the named routine is available, each statement produces a result
set. Each row in the result set corresponds to one `instruction' in the
routine. The first column is `Pos', which is an ordinal number beginning
with 0. The second column is `Instruction', which contains an SQL
statement (usually changed from the original source), or a directive
which has meaning only to the stored-routine handler.

     mysql> DELIMITER //
     mysql> CREATE PROCEDURE p1 ()
         -> BEGIN
         ->   DECLARE fanta INT DEFAULT 55;
         ->   DROP TABLE t2;
         ->   LOOP
         ->     INSERT INTO t3 VALUES (fanta);
         ->     END LOOP;
         ->   END//
     Query OK, 0 rows affected (0.00 sec)

     mysql> SHOW PROCEDURE CODE p1//
     +-----+----------------------------------------+
     | Pos | Instruction                            |
     +-----+----------------------------------------+
     |   0 | set fanta@0 55                         |
     |   1 | stmt 9 "DROP TABLE t2"                 |
     |   2 | stmt 5 "INSERT INTO t3 VALUES (fanta)" |
     |   3 | jump 2                                 |
     +-----+----------------------------------------+
     4 rows in set (0.00 sec)

In this example, the nonexecutable `BEGIN' and `END' statements have
disappeared, and for the `DECLARE VARIABLE_NAME' statement, only the
executable part appears (the part where the default is assigned). For
each statement that is taken from source, there is a code word `stmt'
followed by a type (9 means `DROP', 5 means *Note `INSERT': insert, and
so on). The final row contains an instruction `jump 2', meaning `GOTO
instruction #2'.

*Note `SHOW PROCEDURE CODE': show-procedure-code. was added in MySQL
5.0.17.


File: manual.info,  Node: show-procedure-status,  Next: show-processlist,  Prev: show-procedure-code,  Up: show

13.7.5.26 `SHOW PROCEDURE STATUS' Syntax
........................................

     SHOW PROCEDURE STATUS
         [LIKE 'PATTERN' | WHERE EXPR]

This statement is a MySQL extension. It returns characteristics of a
stored procedure, such as the database, name, type, creator, creation
and modification dates, and character set information. A similar
statement, *Note `SHOW FUNCTION STATUS': show-function-status, displays
information about stored functions (see *Note show-function-status::).

The `LIKE' clause, if present, indicates which procedure or function
names to match. The `WHERE' clause can be given to select rows using
more general conditions, as discussed in *Note extended-show::.

     mysql> SHOW PROCEDURE STATUS LIKE 'sp1'\G
     *************************** 1. row ***************************
                Db: test
              Name: sp1
              Type: PROCEDURE
           Definer: testuser@localhost
          Modified: 2004-08-03 15:29:37
           Created: 2004-08-03 15:29:37
     Security_type: DEFINER
           Comment:

You can also get information about stored routines from the *Note
`ROUTINES': routines-table. table in `INFORMATION_SCHEMA'. See *Note
routines-table::.


File: manual.info,  Node: show-processlist,  Next: show-profile,  Prev: show-procedure-status,  Up: show

13.7.5.27 `SHOW PROCESSLIST' Syntax
...................................

     SHOW [FULL] PROCESSLIST

*Note `SHOW PROCESSLIST': show-processlist. shows you which threads are
running. You can also get this information using the *Note `mysqladmin
processlist': mysqladmin. command. If you have the `PROCESS' privilege,
you can see all threads. Otherwise, you can see only your own threads
(that is, threads associated with the MySQL account that you are
using). If you do not use the `FULL' keyword, only the first 100
characters of each statement are shown in the `Info' field.

This statement is very useful if you get the `too many connections'
error message and want to find out what is going on. MySQL reserves one
extra connection to be used by accounts that have the `SUPER'
privilege, to ensure that administrators should always be able to
connect and check the system (assuming that you are not giving this
privilege to all your users).

Threads can be killed with the *Note `KILL': kill. statement. See *Note
kill::.

Here is an example of *Note `SHOW PROCESSLIST': show-processlist.
output:

     mysql> SHOW FULL PROCESSLIST\G
     *************************** 1. row ***************************
     Id: 1
     User: system user
     Host:
     db: NULL
     Command: Connect
     Time: 1030455
     State: Waiting for master to send event
     Info: NULL
     *************************** 2. row ***************************
     Id: 2
     User: system user
     Host:
     db: NULL
     Command: Connect
     Time: 1004
     State: Has read all relay log; waiting for the slave
            I/O thread to update it
     Info: NULL
     *************************** 3. row ***************************
     Id: 3112
     User: replikator
     Host: artemis:2204
     db: NULL
     Command: Binlog Dump
     Time: 2144
     State: Has sent all binlog to slave; waiting for binlog to be updated
     Info: NULL
     *************************** 4. row ***************************
     Id: 3113
     User: replikator
     Host: iconnect2:45781
     db: NULL
     Command: Binlog Dump
     Time: 2086
     State: Has sent all binlog to slave; waiting for binlog to be updated
     Info: NULL
     *************************** 5. row ***************************
     Id: 3123
     User: stefan
     Host: localhost
     db: apollon
     Command: Query
     Time: 0
     State: NULL
     Info: SHOW FULL PROCESSLIST
     5 rows in set (0.00 sec)

The columns produced by *Note `SHOW PROCESSLIST': show-processlist.
have the following meanings:

   * `Id'

     The connection identifier.

   * `User'

     The MySQL user who issued the statement. If this is `system user',
     it refers to a nonclient thread spawned by the server to handle
     tasks internally.  This could be the I/O or SQL thread used on
     replication slaves or a delayed-row handler. `unauthenticated
     user' refers to a thread that has become associated with a client
     connection but for which authentication of the client user has not
     yet been done. For `system user', there is no host specified in the
     `Host' column.

   * `Host'

     The host name of the client issuing the statement (except for
     `system user' where there is no host).  *Note `SHOW PROCESSLIST':
     show-processlist. reports the host name for TCP/IP connections in
     `HOST_NAME:CLIENT_PORT' format to make it easier to determine
     which client is doing what.

   * `db'

     The default database, if one is selected, otherwise `NULL'.

   * `Command'

     The type of command the thread is executing. For descriptions for
     thread commands, see *Note thread-information::. The value of this
     column corresponds to the `COM_XXX' commands of the client/server
     protocol and `Com_XXX' status variables. See *Note
     server-status-variables::

   * `Time'

     The time in seconds that the thread has been in its current state.

   * `State'

     An action, event, or state that indicates what the thread is
     doing. Descriptions for `State' values can be found at *Note
     thread-information::.

     Most states correspond to very quick operations. If a thread stays
     in a given state for many seconds, there might be a problem that
     needs to be investigated.

     For the *Note `SHOW PROCESSLIST': show-processlist.  statement,
     the value of `State' is `NULL'.

   * `Info'

     The statement the thread is executing, or `NULL' if it is not
     executing any statement. The statement might be the one sent to the
     server, or an innermost statement if the statement executes other
     statements. For example, if a `CALL' statement executes a stored
     procedure that is executing a *Note `SELECT': select. statement,
     the `Info' value shows the *Note `SELECT': select. statement.


File: manual.info,  Node: show-profile,  Next: show-profiles,  Prev: show-processlist,  Up: show

13.7.5.28 `SHOW PROFILE' Syntax
...............................

     SHOW PROFILES

The *Note `SHOW PROFILE': show-profile. statement display profiling
information that indicates resource usage for statements executed
during the course of the current session. It is used together with
*Note `SHOW PROFILES': show-profiles.; see *Note show-profiles::.


File: manual.info,  Node: show-profiles,  Next: show-slave-hosts,  Prev: show-profile,  Up: show

13.7.5.29 `SHOW PROFILES' Syntax
................................

     SHOW PROFILE [TYPE [, TYPE] ... ]
         [FOR QUERY N]
         [LIMIT ROW_COUNT [OFFSET OFFSET]]

     TYPE:
         ALL
       | BLOCK IO
       | CONTEXT SWITCHES
       | CPU
       | IPC
       | MEMORY
       | PAGE FAULTS
       | SOURCE
       | SWAPS

The *Note `SHOW PROFILES': show-profiles. and *Note `SHOW PROFILE':
show-profile. statements display profiling information that indicates
resource usage for statements executed during the course of the current
session.

Profiling is controlled by the `profiling' session variable, which has
a default value of 0 (`OFF').  Profiling is enabled by setting
`profiling' to 1 or `ON':

     mysql> SET profiling = 1;

*Note `SHOW PROFILES': show-profiles. displays a list of the most
recent statements sent to the master. The size of the list is
controlled by the `profiling_history_size' session variable, which has
a default value of 15. The maximum value is 100. Setting the value to 0
has the practical effect of disabling profiling.

All statements are profiled except *Note `SHOW PROFILES':
show-profiles. and *Note `SHOW PROFILE': show-profile, so you will find
neither of those statements in the profile list. Malformed statements
are profiled. For example, `SHOW PROFILING' is an illegal statement,
and a syntax error occurs if you try to execute it, but it will show up
in the profiling list.

*Note `SHOW PROFILE': show-profile. displays detailed information about
a single statement. Without the `FOR QUERY N' clause, the output
pertains to the most recently executed statement. If `FOR QUERY N' is
included, *Note `SHOW PROFILE': show-profile. displays information for
statement N. The values of N correspond to the `Query_ID' values
displayed by *Note `SHOW PROFILES': show-profiles.

The `LIMIT ROW_COUNT' clause may be given to limit the output to
ROW_COUNT rows. If `LIMIT' is given, `OFFSET OFFSET' may be added to
begin the output OFFSET rows into the full set of rows.

By default, *Note `SHOW PROFILE': show-profile. displays `Status' and
`Duration' columns. The `Status' values are like the `State' values
displayed by *Note `SHOW PROCESSLIST': show-processlist, although there
might be some minor differences in interpretion for the two statements
for some status values (see *Note thread-information::).

Optional TYPE values may be specified to display specific additional
types of information:

   * `ALL' displays all information

   * `BLOCK IO' displays counts for block input and output operations

   * `CONTEXT SWITCHES' displays counts for voluntary and involuntary
     context switches

   * `CPU' displays user and system CPU usage times

   * `IPC' displays counts for messages sent and received

   * `MEMORY' is not currently implemented

   * `PAGE FAULTS' displays counts for major and minor page faults

   * `SOURCE' displays the names of functions from the source code,
     together with the name and line number of the file in which the
     function occurs

   * `SWAPS' displays swap counts

Profiling is enabled per session. When a session ends, its profiling
information is lost.

     mysql> SELECT @@profiling;
     +-------------+
     | @@profiling |
     +-------------+
     |           0 |
     +-------------+
     1 row in set (0.00 sec)

     mysql> SET profiling = 1;
     Query OK, 0 rows affected (0.00 sec)

     mysql> DROP TABLE IF EXISTS t1;
     Query OK, 0 rows affected, 1 warning (0.00 sec)

     mysql> CREATE TABLE T1 (id INT);
     Query OK, 0 rows affected (0.01 sec)

     mysql> SHOW PROFILES;
     +----------+----------+--------------------------+
     | Query_ID | Duration | Query                    |
     +----------+----------+--------------------------+
     |        0 | 0.000088 | SET PROFILING = 1        |
     |        1 | 0.000136 | DROP TABLE IF EXISTS t1  |
     |        2 | 0.011947 | CREATE TABLE t1 (id INT) |
     +----------+----------+--------------------------+
     3 rows in set (0.00 sec)

     mysql> SHOW PROFILE;
     +----------------------+----------+
     | Status               | Duration |
     +----------------------+----------+
     | checking permissions | 0.000040 |
     | creating table       | 0.000056 |
     | After create         | 0.011363 |
     | query end            | 0.000375 |
     | freeing items        | 0.000089 |
     | logging slow query   | 0.000019 |
     | cleaning up          | 0.000005 |
     +----------------------+----------+
     7 rows in set (0.00 sec)

     mysql> SHOW PROFILE FOR QUERY 1;
     +--------------------+----------+
     | Status             | Duration |
     +--------------------+----------+
     | query end          | 0.000107 |
     | freeing items      | 0.000008 |
     | logging slow query | 0.000015 |
     | cleaning up        | 0.000006 |
     +--------------------+----------+
     4 rows in set (0.00 sec)

     mysql> SHOW PROFILE CPU FOR QUERY 2;
     +----------------------+----------+----------+------------+
     | Status               | Duration | CPU_user | CPU_system |
     +----------------------+----------+----------+------------+
     | checking permissions | 0.000040 | 0.000038 |   0.000002 |
     | creating table       | 0.000056 | 0.000028 |   0.000028 |
     | After create         | 0.011363 | 0.000217 |   0.001571 |
     | query end            | 0.000375 | 0.000013 |   0.000028 |
     | freeing items        | 0.000089 | 0.000010 |   0.000014 |
     | logging slow query   | 0.000019 | 0.000009 |   0.000010 |
     | cleaning up          | 0.000005 | 0.000003 |   0.000002 |
     +----------------------+----------+----------+------------+
     7 rows in set (0.00 sec)

*Note*:

Profiling is only partially functional on some architectures.  For
values that depend on the `getrusage()' system call, `NULL' is returned
on systems such as Windows that do not support the call. In addition,
profiling is per process and not per thread. This means that activity
on threads within the server other than your own may affect the timing
information that you see.

*Note `SHOW PROFILES': show-profiles. and *Note `SHOW PROFILE':
show-profile. were added in MySQL 5.0.37.

You can also get profiling information from the *Note `PROFILING':
profiling-table. table in `INFORMATION_SCHEMA'. See *Note
profiling-table::. For example, the following queries produce the same
result:

     SHOW PROFILE FOR QUERY 2;

     SELECT STATE, FORMAT(DURATION, 6) AS DURATION
     FROM INFORMATION_SCHEMA.PROFILING
     WHERE QUERY_ID = 2 ORDER BY SEQ;

*Important*:

Please note that the *Note `SHOW PROFILE': show-profile. and *Note
`SHOW PROFILES': show-profiles. functionality is part of the MySQL 5.0
Community Server only.


File: manual.info,  Node: show-slave-hosts,  Next: show-slave-status,  Prev: show-profiles,  Up: show

13.7.5.30 `SHOW SLAVE HOSTS' Syntax
...................................

     SHOW SLAVE HOSTS

Displays a list of replication slaves currently registered with the
master. Only slaves started with the `--report-host=HOST_NAME' option
are visible in this list.

The list is displayed on any server (not just the master server). The
output looks like this:

     mysql> SHOW SLAVE HOSTS;
     +------------+-----------+------+-----------+
     | Server_id  | Host      | Port | Master_id |
     +------------+-----------+------+-----------+
     |  192168010 | iconnect2 | 3306 | 192168011 |
     | 1921680101 | athena    | 3306 | 192168011 |
     +------------+-----------+------+-----------+

   * `Server_id': The unique server ID of the slave server, as
     configured in the server's option file, or on the command line with
     `--server-id=VALUE'.

   * `Host': The host name of the slave server, as configured in the
     server's option file, or on the command line with
     `--report-host=HOST_NAME'.  Note that this can differ from the
     machine name as configured in the operating system.

   * `Port': The port the slave server is listening on.

   * `Master_id': The unique server ID of the master server that the
     slave server is replicating from.

Some MySQL versions report another variable, `Rpl_recovery_rank'. This
variable was never used, and was eventually removed. (Bug #13963)


File: manual.info,  Node: show-slave-status,  Next: show-status,  Prev: show-slave-hosts,  Up: show

13.7.5.31 `SHOW SLAVE STATUS' Syntax
....................................

     SHOW SLAVE STATUS

This statement provides status information on essential parameters of
the slave threads. It requires either the `SUPER' or `REPLICATION
CLIENT' privilege.

If you issue this statement using the *Note `mysql': mysql.  client,
you can use a `\G' statement terminator rather than a semicolon to
obtain a more readable vertical layout:

     mysql> SHOW SLAVE STATUS\G
     *************************** 1. row ***************************
                  Slave_IO_State: Waiting for master to send event
                     Master_Host: localhost
                     Master_User: root
                     Master_Port: 3306
                   Connect_Retry: 3
                 Master_Log_File: gbichot-bin.005
             Read_Master_Log_Pos: 79
                  Relay_Log_File: gbichot-relay-bin.005
                   Relay_Log_Pos: 548
           Relay_Master_Log_File: gbichot-bin.005
                Slave_IO_Running: Yes
               Slave_SQL_Running: Yes
                 Replicate_Do_DB:
             Replicate_Ignore_DB:
              Replicate_Do_Table:
          Replicate_Ignore_Table:
         Replicate_Wild_Do_Table:
     Replicate_Wild_Ignore_Table:
                      Last_Errno: 0
                      Last_Error:
                    Skip_Counter: 0
             Exec_Master_Log_Pos: 79
                 Relay_Log_Space: 552
                 Until_Condition: None
                  Until_Log_File:
                   Until_Log_Pos: 0
              Master_SSL_Allowed: No
              Master_SSL_CA_File:
              Master_SSL_CA_Path:
                 Master_SSL_Cert:
               Master_SSL_Cipher:
                  Master_SSL_Key:
           Seconds_Behind_Master: 8

The following list describes the fields returned by *Note `SHOW SLAVE
STATUS': show-slave-status. For additional information about
interpreting their meanings, see *Note
replication-administration-status::.

   * `Slave_IO_State'

     A copy of the `State' field of the *Note `SHOW PROCESSLIST':
     show-processlist. output for the slave I/O thread. This tells you
     what the thread is doing: trying to connect to the master, waiting
     for events from the master, reconnecting to the master, and so on.
     Possible states are listed in *Note
     replication-implementation-details::. For versions of MySQL prior
     to 5.0.12, it is necessary to check this field for connection
     problems. In those versions, the thread could be running while
     unsuccessfully trying to connect to the master; only this field
     makes you aware of the problem. The state of the SQL thread is not
     copied because it is simpler. If it is running, there is no
     problem; if it is not, you can find the error in the `Last_Error'
     field (described later).

   * `Master_Host'

     The master host that the slave is connected to.

   * `Master_User'

     The user name of the account used to connect to the master.

   * `Master_Port'

     The port used to connect to the master.

   * `Connect_Retry'

     The number of seconds between connect retries (default 60).  This
     can be set with the *Note `CHANGE MASTER TO': change-master-to.
     statement or `--master-connect-retry' option.

   * `Master_Log_File'

     The name of the master binary log file from which the I/O thread
     is currently reading.

   * `Read_Master_Log_Pos'

     The position in the current master binary log file up to which the
     I/O thread has read.

   * `Relay_Log_File'

     The name of the relay log file from which the SQL thread is
     currently reading and executing.

   * `Relay_Log_Pos'

     The position in the current relay log file up to which the SQL
     thread has read and executed.

   * `Relay_Master_Log_File'

     The name of the master binary log file containing the most recent
     event executed by the SQL thread.

   * `Slave_IO_Running'

     Whether the I/O thread is started and has connected successfully
     to the master. Internally, the state of this thread is represented
     by one of the following three values:

        * `MYSQL_SLAVE_NOT_RUN'

          The slave I/O thread is not running. For this state,
          `Slave_IO_Running' is `No'.

        * `MYSQL_SLAVE_RUN_NOT_CONNECT'

          The slave I/O thread is running, but is not connected to a
          replication master. For this state, `Slave_IO_Running'
          depends on the server version as shown in the following table.

          MySQL Version                   `Slave_IO_Running'
          4.1 (4.1.13 and earlier); 5.0   `Yes'
          (5.0.11 and earlier)            
          4.1 (4.1.14 and later); 5.0     `No'
          (5.0.12 and later)              
          5.1, 5.4                        `No'
          5.5                             `Connecting'

        * `MYSQL_SLAVE_RUN_CONNECT'

          The slave I/O thread is running, and is connected to a
          replication master. For this state, `Slave_IO_Running' is
          `Yes'.

   * `Slave_SQL_Running'

     Whether the SQL thread is started.

   * `Replicate_Do_DB', `Replicate_Ignore_DB'

     The lists of databases that were specified with the
     `--replicate-do-db' and `--replicate-ignore-db' options, if any.

   * `Replicate_Do_Table', `Replicate_Ignore_Table',
     `Replicate_Wild_Do_Table', `Replicate_Wild_Ignore_Table'

     The lists of tables that were specified with the
     `--replicate-do-table', `--replicate-ignore-table',
     `--replicate-wild-do-table', and `--replicate-wild-ignore-table'
     options, if any.

   * `Last_Errno', `Last_Error'

     The error number and error message returned by the most recently
     executed statement. An error number of 0 and message of the empty
     string mean `no error.' If the `Last_Error' value is not empty, it
     also appears as a message in the slave's error log. For example:

          Last_Errno: 1051
          Last_Error: error 'Unknown table 'z'' on query 'drop table z'

     The message indicates that the table `z' existed on the master and
     was dropped there, but it did not exist on the slave, so *Note
     `DROP TABLE': drop-table. failed on the slave. (This might occur,
     for example, if you forget to copy the table to the slave when
     setting up replication.)

     *Note*:

     When the slave SQL thread receives an error, it reports the error
     first, then stops the SQL thread. This means that there is a small
     window of time during which *Note `SHOW SLAVE STATUS':
     show-slave-status. shows a nonzero value for `Last_Errno' even
     though `Slave_SQL_Running' still displays `Yes'.

   * `Skip_Counter'

     The current value of the `sql_slave_skip_counter' system variable.
     See *Note set-global-sql-slave-skip-counter::.

   * `Exec_Master_Log_Pos'

     The position in the current master binary log file to which the
     SQL thread has read and executed, marking the start of the next
     transaction or event to be processed. You can use this value with
     the *Note `CHANGE MASTER TO': change-master-to. statement's
     `MASTER_LOG_POS' option when starting a new slave from an existing
     slave, so that the new slave reads from this point. The
     coordinates given by (`Relay_Master_Log_File',
     `Exec_Master_Log_Pos') in the master's binary log correspond to
     the coordinates given by (`Relay_Log_File', `Relay_Log_Pos') in
     the relay log.

   * `Relay_Log_Space'

     The total combined size of all existing relay log files.

   * `Until_Condition', `Until_Log_File', `Until_Log_Pos'

     The values specified in the `UNTIL' clause of the *Note `START
     SLAVE': start-slave. statement.

     `Until_Condition' has these values:

        * `None' if no `UNTIL' clause was specified

        * `Master' if the slave is reading until a given position in
          the master's binary log

        * `Relay' if the slave is reading until a given position in its
          relay log

     `Until_Log_File' and `Until_Log_Pos' indicate the log file name
     and position that define the coordinates at which the SQL thread
     stops executing.

   * `Master_SSL_Allowed', `Master_SSL_CA_File', `Master_SSL_CA_Path',
     `Master_SSL_Cert', `Master_SSL_Cipher', `Master_SSL_Key'

     These fields show the SSL parameters used by the slave to connect
     to the master, if any.

     `Master_SSL_Allowed' has these values:

        * `Yes' if an SSL connection to the master is permitted

        * `No' if an SSL connection to the master is not permitted

        * `Ignored' if an SSL connection is permitted but the slave
          server does not have SSL support enabled

     The values of the other SSL-related fields correspond to the
     values of the `MASTER_SSL_CA', `MASTER_SSL_CAPATH',
     `MASTER_SSL_CERT', `MASTER_SSL_CIPHER', and `MASTER_SSL_KEY'
     options to the *Note `CHANGE MASTER TO': change-master-to.
     statement.  See *Note change-master-to::.

   * `Seconds_Behind_Master'

     This field is an indication of how `late' the slave is:

        * When the slave SQL thread is actively processing updates,
          this field is the number of seconds that have elapsed since
          the timestamp of the most recent event on the master executed
          by that thread.

        * When the SQL thread has caught up to the slave I/O thread and
          is idle waiting for more events from the I/O thread, this
          field is zero.

     In essence, this field measures the time difference in seconds
     between the slave SQL thread and the slave I/O thread.

     If the network connection between master and slave is fast, the
     slave I/O thread is very close to the master, so this field is a
     good approximation of how late the slave SQL thread is compared to
     the master. If the network is slow, this is _not_ a good
     approximation; the slave SQL thread may quite often be caught up
     with the slow-reading slave I/O thread, so `Seconds_Behind_Master'
     often shows a value of 0, even if the I/O thread is late compared
     to the master.  In other words, _this column is useful only for
     fast networks_.

     This time difference computation works even though the master and
     slave do not have identical clocks (the clock difference is
     computed when the slave I/O thread starts, and assumed to remain
     constant from then on).  `Seconds_Behind_Master' is `NULL'
     (`unknown') if the slave SQL thread is not running, or if the
     slave I/O thread is not running or not connected to master. For
     example, if the slave I/O thread is running but is not connected
     to the master and is sleeping for the number of seconds given by
     the *Note `CHANGE MASTER TO': change-master-to.  statement or
     `--master-connect-retry' option (default 60) before reconnecting,
     the value is `NULL'. This is because the slave cannot know what
     the master is doing, and so cannot say reliably how late it is.

     The value of this field is based on the timestamps stored in
     events, which are preserved through replication. This means that
     if a master M1 is itself a slave of M0, any event from M1's binary
     log that originates from M0's binary log has M0's timestamp for
     that event. This enables MySQL to replicate *Note `TIMESTAMP':
     datetime.  successfully. However, the problem for
     `Seconds_Behind_Master' is that if M1 also receives direct updates
     from clients, the `Seconds_Behind_Master' value randomly
     fluctuates because sometimes the last event from M1 originates
     from M0 and sometimes is the result of a direct update on M1.


File: manual.info,  Node: show-status,  Next: show-table-status,  Prev: show-slave-status,  Up: show

13.7.5.32 `SHOW STATUS' Syntax
..............................

     SHOW [GLOBAL | SESSION] STATUS
         [LIKE 'PATTERN' | WHERE EXPR]

*Note `SHOW STATUS': show-status. provides server status information.
This information also can be obtained using the *Note `mysqladmin
extended-status': mysqladmin. command. The `LIKE' clause, if present,
indicates which variable names to match. The `WHERE' clause can be
given to select rows using more general conditions, as discussed in
*Note extended-show::.  This statement does not require any privilege.
It requires only the ability to connect to the server.

Partial output is shown here. The list of names and values may be
different for your server. The meaning of each variable is given in
*Note server-status-variables::.

     mysql> SHOW STATUS;
     +--------------------------+------------+
     | Variable_name            | Value      |
     +--------------------------+------------+
     | Aborted_clients          | 0          |
     | Aborted_connects         | 0          |
     | Bytes_received           | 155372598  |
     | Bytes_sent               | 1176560426 |
     | Connections              | 30023      |
     | Created_tmp_disk_tables  | 0          |
     | Created_tmp_tables       | 8340       |
     | Created_tmp_files        | 60         |
     ...
     | Open_tables              | 1          |
     | Open_files               | 2          |
     | Open_streams             | 0          |
     | Opened_tables            | 44600      |
     | Questions                | 2026873    |
     ...
     | Table_locks_immediate    | 1920382    |
     | Table_locks_waited       | 0          |
     | Threads_cached           | 0          |
     | Threads_created          | 30022      |
     | Threads_connected        | 1          |
     | Threads_running          | 1          |
     | Uptime                   | 80380      |
     +--------------------------+------------+

With a `LIKE' clause, the statement displays only rows for those
variables with names that match the pattern:

     mysql> SHOW STATUS LIKE 'Key%';
     +--------------------+----------+
     | Variable_name      | Value    |
     +--------------------+----------+
     | Key_blocks_used    | 14955    |
     | Key_read_requests  | 96854827 |
     | Key_reads          | 162040   |
     | Key_write_requests | 7589728  |
     | Key_writes         | 3813196  |
     +--------------------+----------+

The `GLOBAL' and `SESSION' options are new in MySQL 5.0.2. With the
`GLOBAL' modifier, *Note `SHOW STATUS': show-status. displays the
status values for all connections to MySQL. With `SESSION', it displays
the status values for the current connection. If no modifier is
present, the default is `SESSION'.  `LOCAL' is a synonym for `SESSION'.

Some status variables have only a global value. For these, you get the
same value for both `GLOBAL' and `SESSION'. The scope for each status
variable is listed at *Note server-status-variables::.

*Note*:

Before MySQL 5.0.2, *Note `SHOW STATUS': show-status.  returned global
status values. Because the default as of 5.0.2 is to return session
values, this is incompatible with previous versions. To issue a *Note
`SHOW STATUS': show-status. statement that will retrieve global status
values for all versions of MySQL, write it like this:

     SHOW /*!50002 GLOBAL */ STATUS;


File: manual.info,  Node: show-table-status,  Next: show-tables,  Prev: show-status,  Up: show

13.7.5.33 `SHOW TABLE STATUS' Syntax
....................................

     SHOW TABLE STATUS [{FROM | IN} DB_NAME]
         [LIKE 'PATTERN' | WHERE EXPR]

*Note `SHOW TABLE STATUS': show-table-status. works likes *Note `SHOW
TABLES': show-tables, but provides a lot of information about each
non-`TEMPORARY' table. You can also get this list using the *Note
`mysqlshow --status DB_NAME': mysqlshow. command.  The `LIKE' clause,
if present, indicates which table names to match. The `WHERE' clause
can be given to select rows using more general conditions, as discussed
in *Note extended-show::.

As of MySQL 5.0.1, this statement also displays information about views.

*Note `SHOW TABLE STATUS': show-table-status. returns the following
fields:

   * `Name'

     The name of the table.

   * `Engine'

     The storage engine for the table. See *Note storage-engines::.

   * `Version'

     The version number of the table's `.frm' file.

   * `Row_format'

     The row-storage format (`Fixed', `Dynamic', `Compressed',
     `Redundant', `Compact').  For `MyISAM' tables, (`Dynamic'
     corresponds to what *Note `myisamchk -dvv': myisamchk. reports as
     `Packed'. Starting with MySQL/InnoDB 5.0.3, the format of `InnoDB'
     tables is reported as `Redundant' or `Compact'. Prior to 5.0.3,
     `InnoDB' tables are always in the `Redundant' format.

   * `Rows'

     The number of rows. Some storage engines, such as `MyISAM', store
     the exact count. For other storage engines, such as `InnoDB', this
     value is an approximation, and may vary from the actual value by
     as much as 40 to 50%. In such cases, use `SELECT COUNT(*)' to
     obtain an accurate count.

     The `Rows' value is `NULL' for tables in the `INFORMATION_SCHEMA'
     database.

   * `Avg_row_length'

     The average row length.

   * `Data_length'

     The length of the data file.

   * `Max_data_length'

     The maximum length of the data file. This is the total number of
     bytes of data that can be stored in the table, given the data
     pointer size used.

   * `Index_length'

     The length of the index file.

   * `Data_free'

     The number of allocated but unused bytes.

   * `Auto_increment'

     The next `AUTO_INCREMENT' value.

   * `Create_time'

     When the table was created.

   * `Update_time'

     When the data file was last updated. For some storage engines,
     this value is `NULL'. For example, `InnoDB' stores multiple tables
     in its tablespace and the data file timestamp does not apply. For
     `MyISAM', the data file timestamp is used; however, on Windows the
     timestamp is not updated by updates so the value is inaccurate.

   * `Check_time'

     When the table was last checked. Not all storage engines update
     this time, in which case the value is always `NULL'.

   * `Collation'

     The table's character set and collation.

   * `Checksum'

     The live checksum value (if any).

   * `Create_options'

     Extra options used with *Note `CREATE TABLE': create-table. The
     original options supplied when *Note `CREATE TABLE': create-table.
     is called are retained and the options reported here may differ
     from the active table settings and options.

   * `Comment'

     The comment used when creating the table (or information as to why
     MySQL could not access the table information).

In the table comment, `InnoDB' tables report the free space of the
tablespace to which the table belongs. For a table located in the
shared tablespace, this is the free space of the shared tablespace. If
you are using multiple tablespaces and the table has its own
tablespace, the free space is for only that table. Free space means the
number of completely free 1MB extents minus a safety margin. Even if
free space displays as 0, it may be possible to insert rows as long as
new extents need not be allocated.

For `MEMORY' tables, the `Data_length', `Max_data_length', and
`Index_length' values approximate the actual amount of allocated
memory. The allocation algorithm reserves memory in large amounts to
reduce the number of allocation operations.

Beginning with MySQL 5.0.3, for *Note `NDBCLUSTER': mysql-cluster.
tables, the output of this statement shows appropriate values for the
`Avg_row_length' and `Data_length' columns, with the exception that
*Note `BLOB': blob. columns are not taken into account. In addition,
the number of replicas is now shown in the `Comment' column (as
`number_of_replicas').

For views, all the fields displayed by *Note `SHOW TABLE STATUS':
show-table-status. are `NULL' except that `Name' indicates the view
name and `Comment' says `view'.


File: manual.info,  Node: show-tables,  Next: show-triggers,  Prev: show-table-status,  Up: show

13.7.5.34 `SHOW TABLES' Syntax
..............................

     SHOW [FULL] TABLES [{FROM | IN} DB_NAME]
         [LIKE 'PATTERN' | WHERE EXPR]

*Note `SHOW TABLES': show-tables. lists the non-`TEMPORARY' tables in a
given database. You can also get this list using the *Note `mysqlshow
DB_NAME': mysqlshow. command. The `LIKE' clause, if present, indicates
which table names to match. The `WHERE' clause can be given to select
rows using more general conditions, as discussed in *Note
extended-show::.

Before MySQL 5.0.1, the output from *Note `SHOW TABLES': show-tables.
contains a single column of table names.  Beginning with MySQL 5.0.1,
this statement also lists any views in the database. As of MySQL 5.0.2,
the `FULL' modifier is supported such that *Note `SHOW FULL TABLES':
show-tables. displays a second output column. Values for the second
column are `BASE TABLE' for a table and `VIEW' for a view.

If you have no privileges for a base table or view, it does not show up
in the output from *Note `SHOW TABLES': show-tables. or *Note
`mysqlshow db_name': mysqlshow.


File: manual.info,  Node: show-triggers,  Next: show-variables,  Prev: show-tables,  Up: show

13.7.5.35 `SHOW TRIGGERS' Syntax
................................

     SHOW TRIGGERS [{FROM | IN} DB_NAME]
         [LIKE 'PATTERN' | WHERE EXPR]

*Note `SHOW TRIGGERS': show-triggers. lists the triggers currently
defined for tables in a database (the default database unless a `FROM'
clause is given). This statement returns results only if you have the
`SUPER' privilege. It was implemented in MySQL 5.0.10. The `LIKE'
clause, if present, indicates which table names to match and causes the
statement to display triggers for those tables. The `WHERE' clause can
be given to select rows using more general conditions, as discussed in
*Note extended-show::.

For the trigger `ins_sum' as defined in *Note triggers::, the output of
this statement is as shown here:

     mysql> SHOW TRIGGERS LIKE 'acc%'\G
     *************************** 1. row ***************************
       Trigger: ins_sum
         Event: INSERT
         Table: account
     Statement: SET @sum = @sum + NEW.amount
        Timing: BEFORE
       Created: NULL
      sql_mode:
       Definer: myname@localhost

*Note*:

When using a `LIKE' clause with *Note `SHOW TRIGGERS': show-triggers,
the expression to be matched (EXPR) is compared with the name of the
table on which the trigger is declared, and not with the name of the
trigger:

     mysql> SHOW TRIGGERS LIKE 'ins%';
     Empty set (0.01 sec)

A brief explanation of the columns in the output of this statement is
shown here:

   * `Trigger'

     The name of the trigger.

   * `Event'

     The event that causes trigger activation: one of `'INSERT'',
     `'UPDATE'', or `'DELETE''.

   * `Table'

     The table for which the trigger is defined.

   * `Statement'

     The statement to be executed when the trigger is activated.  This
     is the same as the text shown in the `ACTION_STATEMENT' column of
     *Note `INFORMATION_SCHEMA.TRIGGERS': triggers-table.

   * `Timing'

     One of the two values `'BEFORE'' or `'AFTER''.

   * `Created'

     Currently, the value of this column is always `NULL'.

   * `sql_mode'

     The SQL mode in effect when the trigger executes. This column was
     added in MySQL 5.0.11.

   * `Definer'

     The account that created the trigger. This column was added in
     MySQL 5.0.17.

You must have the `SUPER' privilege to execute *Note `SHOW TRIGGERS':
show-triggers.

See also *Note triggers-table::.


File: manual.info,  Node: show-variables,  Next: show-warnings,  Prev: show-triggers,  Up: show

13.7.5.36 `SHOW VARIABLES' Syntax
.................................

     SHOW [GLOBAL | SESSION] VARIABLES
         [LIKE 'PATTERN' | WHERE EXPR]

*Note `SHOW VARIABLES': show-variables. shows the values of MySQL
system variables. This information also can be obtained using the *Note
`mysqladmin variables': mysqladmin. command. The `LIKE' clause, if
present, indicates which variable names to match. The `WHERE' clause
can be given to select rows using more general conditions, as discussed
in *Note extended-show::.  This statement does not require any
privilege. It requires only the ability to connect to the server.

With the `GLOBAL' modifier, *Note `SHOW VARIABLES': show-variables.
displays the values that are used for new connections to MySQL. If a
variable has no global value, the session value is displayed. With
`SESSION', *Note `SHOW VARIABLES': show-variables. displays the values
that are in effect for the current connection. If no modifier is
present, the default is `SESSION'. `LOCAL' is a synonym for `SESSION'.

If the default system variable values are unsuitable, you can set them
using command options when *Note `mysqld': mysqld.  starts, and most
can be changed at runtime with the *Note `SET': set-option.  statement.
See *Note using-system-variables::, and *Note set-option::.

Partial output is shown here. The list of names and values may be
different for your server.  *Note server-system-variables::, describes
the meaning of each variable, and *Note server-parameters::, provides
information about tuning them.

     mysql> SHOW VARIABLES;
     +---------------------------------+-------------------------------------+
     | Variable_name                   | Value                               |
     +---------------------------------+-------------------------------------+
     | auto_increment_increment        | 1                                   |
     | auto_increment_offset           | 1                                   |
     | automatic_sp_privileges         | ON                                  |
     | back_log                        | 50                                  |
     | basedir                         | /                                   |
     | bdb_cache_size                  | 8388600                             |
     | bdb_home                        | /var/lib/mysql/                     |
     | bdb_log_buffer_size             | 32768                               |
     ...
     | max_connections                 | 100                                 |
     | max_connect_errors              | 10                                  |
     | max_delayed_threads             | 20                                  |
     | max_error_count                 | 64                                  |
     | max_heap_table_size             | 16777216                            |
     | max_join_size                   | 4294967295                          |
     | max_relay_log_size              | 0                                   |
     | max_sort_length                 | 1024                                |
     ...
     | time_zone                       | SYSTEM                              |
     | timed_mutexes                   | OFF                                 |
     | tmp_table_size                  | 33554432                            |
     | tmpdir                          |                                     |
     | transaction_alloc_block_size    | 8192                                |
     | transaction_prealloc_size       | 4096                                |
     | tx_isolation                    | REPEATABLE-READ                     |
     | updatable_views_with_limit      | YES                                 |
     | version                         | 5.0.19-Max                          |
     | version_comment                 | MySQL Community Edition - Max (GPL) |
     | version_compile_machine         | i686                                |
     | version_compile_os              | pc-linux-gnu                        |
     | wait_timeout                    | 28800                               |
     +---------------------------------+-------------------------------------+

With a `LIKE' clause, the statement displays only rows for those
variables with names that match the pattern. To obtain the row for a
specific variable, use a `LIKE' clause as shown:

     SHOW VARIABLES LIKE 'max_join_size';
     SHOW SESSION VARIABLES LIKE 'max_join_size';

To get a list of variables whose name match a pattern, use the ``%''
wildcard character in a `LIKE' clause:

     SHOW VARIABLES LIKE '%size%';
     SHOW GLOBAL VARIABLES LIKE '%size%';

Wildcard characters can be used in any position within the pattern to
be matched. Strictly speaking, because ``_'' is a wildcard that matches
any single character, you should escape it as ``\_'' to match it
literally. In practice, this is rarely necessary.


File: manual.info,  Node: show-warnings,  Prev: show-variables,  Up: show

13.7.5.37 `SHOW WARNINGS' Syntax
................................

     SHOW WARNINGS [LIMIT [OFFSET,] ROW_COUNT]
     SHOW COUNT(*) WARNINGS

*Note `SHOW WARNINGS': show-warnings. shows information about the
conditions (errors, warnings, and notes) that resulted from the last
statement in the current session that generated messages. It shows
nothing if the last statement used a table and generated no messages.
(That is, a statement that uses a table but generates no messages
clears the message list.)  Statements that do not use tables and do not
generate messages have no effect on the message list.

Warnings are generated for DML statements such as *Note `INSERT':
insert, *Note `UPDATE': update, and *Note `LOAD DATA INFILE':
load-data. as well as DDL statements such as *Note `CREATE TABLE':
create-table. and *Note `ALTER TABLE': alter-table.

The `LIMIT' clause has the same syntax as for the *Note `SELECT':
select. statement. See *Note select::.

A related statement, *Note `SHOW ERRORS': show-errors, shows only the
error conditions (it excludes warnings and notes). See *Note
show-errors::.

The *Note `SHOW COUNT(*) WARNINGS': show-warnings. statement displays
the total number of errors, warnings, and notes. You can also retrieve
this number from the `warning_count' system variable:

     SHOW COUNT(*) WARNINGS;
     SELECT @@warning_count;

Here is a simple example that shows a syntax warning for *Note `CREATE
TABLE': create-table. and conversion warnings for *Note `INSERT':
insert.:

     mysql> CREATE TABLE t1
          >   (a TINYINT NOT NULL, b CHAR(4))
          >   TYPE=MyISAM;
     Query OK, 0 rows affected, 1 warning (0.00 sec)
     mysql> SHOW WARNINGS\G
     *************************** 1. row ***************************
       Level: Warning
        Code: 1287
     Message: 'TYPE=storage_engine' is deprecated, use
              'ENGINE=storage_engine' instead
     1 row in set (0.00 sec)

     mysql> INSERT INTO t1 VALUES(10,'mysql'),
         -> (NULL,'test'), (300,'Open Source');
     Query OK, 3 rows affected, 4 warnings (0.01 sec)
     Records: 3  Duplicates: 0  Warnings: 4

     mysql> SHOW WARNINGS\G
     *************************** 1. row ***************************
       Level: Warning
        Code: 1265
     Message: Data truncated for column 'b' at row 1
     *************************** 2. row ***************************
       Level: Warning
        Code: 1263
     Message: Data truncated, NULL supplied to NOT NULL column 'a' at row 2
     *************************** 3. row ***************************
       Level: Warning
        Code: 1264
     Message: Data truncated, out of range for column 'a' at row 3
     *************************** 4. row ***************************
       Level: Warning
        Code: 1265
     Message: Data truncated for column 'b' at row 3
     4 rows in set (0.00 sec)

The `max_error_count' system variable controls the maximum number of
error, warning, and note messages for which the server stores
information, and thus the number of messages that *Note `SHOW
WARNINGS': show-warnings. displays. By default, `max_error_count' is
64. To change the number of messages the server can store, change the
value of `max_error_count'.

The value of `warning_count' is not limited by `max_error_count' if the
number of messages generated exceeds `max_error_count'.

In the following example, the *Note `ALTER TABLE': alter-table.
statement produces three warning messages (as shown by the value of
`warning_count'), but only one is stored because `max_error_count' has
been set to 1:

     mysql> SHOW VARIABLES LIKE 'max_error_count';
     +-----------------+-------+
     | Variable_name   | Value |
     +-----------------+-------+
     | max_error_count | 64    |
     +-----------------+-------+
     1 row in set (0.00 sec)

     mysql> SET max_error_count=1;
     Query OK, 0 rows affected (0.00 sec)

     mysql> ALTER TABLE t1 MODIFY b CHAR;
     Query OK, 3 rows affected, 3 warnings (0.00 sec)
     Records: 3  Duplicates: 0  Warnings: 3

     mysql> SELECT @@warning_count;
     +-----------------+
     | @@warning_count |
     +-----------------+
     |               3 |
     +-----------------+
     1 row in set (0.01 sec)

     mysql> SHOW WARNINGS;
     +---------+------+----------------------------------------+
     | Level   | Code | Message                                |
     +---------+------+----------------------------------------+
     | Warning | 1263 | Data truncated for column 'b' at row 1 |
     +---------+------+----------------------------------------+
     1 row in set (0.00 sec)

To disable warnings, set `max_error_count' to 0. In this case,
`warning_count' still indicates how many warnings have occurred, but
none of the messages are stored.

The following *Note `DROP TABLE': drop-table.  statement results in a
note:

     mysql> DROP TABLE IF EXISTS test.no_such_table;
     Query OK, 0 rows affected, 1 warning (0.01 sec)
     mysql> SHOW WARNINGS;
     +-------+------+-------------------------------+
     | Level | Code | Message                       |
     +-------+------+-------------------------------+
     | Note  | 1051 | Unknown table 'no_such_table' |
     +-------+------+-------------------------------+

If the `sql_notes' system variable is set to 0, notes do not increment
`warning_count' and the server does not record them.

The MySQL server sends back a count indicating the total number of
errors, warnings, and notes resulting from the last statement. From the
C API, this value can be obtained by calling *Note
`mysql_warning_count()': mysql-warning-count. See *Note
mysql-warning-count::.


File: manual.info,  Node: other-administrative-sql,  Prev: show,  Up: sql-syntax-server-administration

13.7.6 Other Administrative Statements
--------------------------------------

* Menu:

* cache-index::                  `CACHE INDEX' Syntax
* flush::                        `FLUSH' Syntax
* kill::                         `KILL' Syntax
* load-index::                   `LOAD INDEX INTO CACHE' Syntax
* reset::                        `RESET' Syntax


File: manual.info,  Node: cache-index,  Next: flush,  Prev: other-administrative-sql,  Up: other-administrative-sql

13.7.6.1 `CACHE INDEX' Syntax
.............................

     CACHE INDEX
       TBL_INDEX_LIST [, TBL_INDEX_LIST] ...
       IN KEY_CACHE_NAME

     TBL_INDEX_LIST:
       TBL_NAME [[INDEX|KEY] (INDEX_NAME[, INDEX_NAME] ...)]

The *Note `CACHE INDEX': cache-index. statement assigns table indexes
to a specific key cache. It is used only for `MyISAM' tables. After the
indexes have been assigned, they can be preloaded into the cache if
desired with *Note `LOAD INDEX INTO CACHE': load-index.

The following statement assigns indexes from the tables `t1', `t2', and
`t3' to the key cache named `hot_cache':

     mysql> CACHE INDEX t1, t2, t3 IN hot_cache;
     +---------+--------------------+----------+----------+
     | Table   | Op                 | Msg_type | Msg_text |
     +---------+--------------------+----------+----------+
     | test.t1 | assign_to_keycache | status   | OK       |
     | test.t2 | assign_to_keycache | status   | OK       |
     | test.t3 | assign_to_keycache | status   | OK       |
     +---------+--------------------+----------+----------+

The syntax of *Note `CACHE INDEX': cache-index. enables you to specify
that only particular indexes from a table should be assigned to the
cache. The current implementation assigns all the table's indexes to
the cache, so there is no reason to specify anything other than the
table name.

The key cache referred to in a *Note `CACHE INDEX': cache-index.
statement can be created by setting its size with a parameter setting
statement or in the server parameter settings. For example:

     mysql> SET GLOBAL keycache1.key_buffer_size=128*1024;

Key cache parameters can be accessed as members of a structured system
variable. See *Note structured-system-variables::.

A key cache must exist before you can assign indexes to it:

     mysql> CACHE INDEX t1 IN non_existent_cache;
     ERROR 1284 (HY000): Unknown key cache 'non_existent_cache'

By default, table indexes are assigned to the main (default) key cache
created at the server startup. When a key cache is destroyed, all
indexes assigned to it become assigned to the default key cache again.

Index assignment affects the server globally: If one client assigns an
index to a given cache, this cache is used for all queries involving
the index, no matter which client issues the queries.


File: manual.info,  Node: flush,  Next: kill,  Prev: cache-index,  Up: other-administrative-sql

13.7.6.2 `FLUSH' Syntax
.......................

     FLUSH [NO_WRITE_TO_BINLOG | LOCAL]
         FLUSH_OPTION [, FLUSH_OPTION] ...

The *Note `FLUSH': flush. statement clears or reloads various internal
caches used by MySQL. One variant acquires a lock. To execute *Note
`FLUSH': flush, you must have the `RELOAD' privilege.

By default, *Note `FLUSH': flush. statements are written to the binary
log so that they will be replicated to replication slaves. Logging can
be suppressed with the optional `NO_WRITE_TO_BINLOG' keyword or its
alias `LOCAL'.

*Note*:

*Note `FLUSH LOGS': flush, *Note `FLUSH MASTER': flush, *Note `FLUSH
SLAVE': flush, and *Note `FLUSH TABLES WITH READ LOCK': flush. are not
written to the binary log in any case because they would cause problems
if replicated to a slave.

The *Note `RESET': reset. statement is similar to *Note `FLUSH': flush.
See *Note reset::, for information about using the *Note `RESET':
reset. statement with replication.

FLUSH_OPTION can be any of the following items:

   * `DES_KEY_FILE'

     Reloads the DES keys from the file that was specified with the
     `--des-key-file' option at server startup time.

   * `HOSTS'

     Empties the host cache tables. You should flush the host tables if
     some of your hosts change IP address or if you get the error
     message `Host 'HOST_NAME' is blocked'.  When more than
     `max_connect_errors' errors occur successively for a given host
     while connecting to the MySQL server, MySQL assumes that something
     is wrong and blocks the host from further connection requests.
     Flushing the host tables enables further connection attempts from
     the host. See *Note blocked-host::. You can start *Note `mysqld':
     mysqld. with `--max_connect_errors=999999999' to avoid this error
     message.

   * `LOGS'

     Closes and reopens all log files. If binary logging is enabled,
     the sequence number of the binary log file is incremented by one
     relative to the previous file. On Unix, this is the same thing as
     sending a `SIGHUP' signal to the *Note `mysqld': mysqld. server
     (except on some Mac OS X 10.3 versions where *Note `mysqld':
     mysqld. ignores `SIGHUP' and `SIGQUIT').

     If you execute *Note `FLUSH LOGS': flush. and *Note `mysqld':
     mysqld. is writing the error log to a file (for example, if it was
     started with the `--log-error' option), log file renaming occurs
     as described in *Note error-log::.

   * `MASTER'

     Deletes all binary logs, resets the binary log index file and
     creates a new binary log.  *Note `FLUSH MASTER': flush. is
     deprecated in favor of *Note `RESET MASTER': reset-master.  *Note
     `FLUSH MASTER': flush. is still accepted in MySQL 5.0 for backward
     compatibility, but is removed in MySQL 5.6. See *Note
     reset-master::.

   * `PRIVILEGES'

     Reloads the privileges from the grant tables in the `mysql'
     database. On Unix, this also occurs if the server receives a
     `SIGHUP' signal.

     The server caches information in memory as a result of *Note
     `GRANT': grant. and *Note `CREATE USER': create-user. statements.
     This memory is not released by the corresponding *Note `REVOKE':
     revoke. and *Note `DROP USER': drop-user. statements, so for a
     server that executes many instances of the statements that cause
     caching, there will be an increase in memory use. This cached
     memory can be freed with *Note `FLUSH PRIVILEGES': flush.

   * `QUERY CACHE'

     Defragment the query cache to better utilize its memory.  *Note
     `FLUSH QUERY CACHE': flush. does not remove any queries from the
     cache, unlike *Note `FLUSH TABLES': flush. or `RESET QUERY CACHE'.

   * `SLAVE'

     Resets all replication slave parameters, including relay log files
     and replication position in the master's binary logs.  *Note
     `FLUSH SLAVE': flush.  is deprecated in favor of *Note `RESET
     SLAVE': reset-slave.  *Note `FLUSH SLAVE': flush.  is still
     accepted in MySQL 5.0 for backward compatibility, but is removed
     in MySQL 5.6. See *Note reset-slave::.

   * `STATUS'

     This option adds the current thread's session status variable
     values to the global values and resets the session values to zero.
     It also resets the counters for key caches (default and named) to
     zero and sets `Max_used_connections' to the current number of open
     connections. This is something you should use only when debugging
     a query. See *Note bug-reports::.

   * `TABLES'

     *Note `FLUSH TABLES': flush. has several variant forms.  *Note
     `FLUSH TABLE': flush.  is a synonym for *Note `FLUSH TABLES':
     flush, except that `TABLE' does not work with the `WITH READ LOCK'
     variant.

        * `FLUSH TABLES'

          Closes all open tables, forces all tables in use to be
          closed, and flushes the query cache.  *Note `FLUSH TABLES':
          flush. also removes all query results from the query cache,
          like the `RESET QUERY CACHE' statement.

        * `FLUSH TABLES TBL_NAME [, TBL_NAME] ...'

          With a list of one or more comma-separated table names, this
          is like *Note `FLUSH TABLES': flush. with no names except
          that the server flushes only the named tables. No error
          occurs if a named table does not exist.

        * `FLUSH TABLES WITH READ LOCK'

          Closes all open tables and locks all tables for all databases
          with a global read lock until you explicitly release the lock
          by executing *Note `UNLOCK TABLES': lock-tables. This is a
          very convenient way to get backups if you have a file system
          such as Veritas or ZFS that can take snapshots in time.

          *Note `FLUSH TABLES WITH READ LOCK': flush. acquires a global
          read lock and not table locks, so it is not subject to the
          same behavior as *Note `LOCK TABLES': lock-tables. and *Note
          `UNLOCK TABLES': lock-tables. with respect to table locking
          and implicit commits:

             * *Note `UNLOCK TABLES': lock-tables. implicitly commits
               any active transaction only if any tables currently have
               been locked with *Note `LOCK TABLES': lock-tables. The
               commit does not occur for *Note `UNLOCK TABLES':
               lock-tables. following *Note `FLUSH TABLES WITH READ
               LOCK': flush. because the latter statement does not
               acquire table locks.

             * Beginning a transaction causes table locks acquired with
               *Note `LOCK TABLES': lock-tables. to be released, as
               though you had executed *Note `UNLOCK TABLES':
               lock-tables. Beginning a transaction does not release a
               global read lock acquired with *Note `FLUSH TABLES WITH
               READ LOCK': flush.

   * `USER_RESOURCES'

     Resets all per-hour user resources to zero. This enables clients
     that have reached their hourly connection, query, or update limits
     to resume activity immediately.  *Note `FLUSH USER_RESOURCES':
     flush. does not apply to the limit on maximum simultaneous
     connections. See *Note user-resources::.

The *Note `mysqladmin': mysqladmin. utility provides a command-line
interface to some flush operations, using commands such as
`flush-hosts', `flush-logs', `flush-privileges', `flush-status', and
`flush-tables'.

Using *Note `FLUSH': flush. statements within stored functions or
triggers is not supported in MySQL 5.0. However, you may use *Note
`FLUSH': flush. in stored procedures, so long as these are not called
from stored functions or triggers.  See *Note
stored-program-restrictions::.


File: manual.info,  Node: kill,  Next: load-index,  Prev: flush,  Up: other-administrative-sql

13.7.6.3 `KILL' Syntax
......................

     KILL [CONNECTION | QUERY] THREAD_ID

Each connection to *Note `mysqld': mysqld. runs in a separate thread.
You can see which threads are running with the *Note `SHOW
PROCESSLIST': show-processlist. statement and kill a thread with the
`KILL THREAD_ID' statement.

In MySQL 5.0.0, *Note `KILL': kill. permits an optional `CONNECTION' or
`QUERY' modifier:

   * *Note `KILL CONNECTION': kill. is the same as *Note `KILL': kill.
     with no modifier: It terminates the connection associated with the
     given THREAD_ID.

   * *Note `KILL QUERY': kill.  terminates the statement that the
     connection is currently executing, but leaves the connection
     itself intact.

If you have the `PROCESS' privilege, you can see all threads. If you
have the `SUPER' privilege, you can kill all threads and statements.
Otherwise, you can see and kill only your own threads and statements.

You can also use the *Note `mysqladmin processlist': mysqladmin.  and
*Note `mysqladmin kill': mysqladmin. commands to examine and kill
threads.

*Note*:

You cannot use *Note `KILL': kill. with the Embedded MySQL Server
library because the embedded server merely runs inside the threads of
the host application. It does not create any connection threads of its
own.

When you use *Note `KILL': kill, a thread-specific kill flag is set for
the thread. In most cases, it might take some time for the thread to
die because the kill flag is checked only at specific intervals:

   * In *Note `SELECT': select, `ORDER BY' and `GROUP BY' loops, the
     flag is checked after reading a block of rows. If the kill flag is
     set, the statement is aborted.

   * During *Note `ALTER TABLE': alter-table, the kill flag is checked
     before each block of rows are read from the original table. If the
     kill flag was set, the statement is aborted and the temporary
     table is deleted.

   * During *Note `UPDATE': update. or *Note `DELETE': delete.
     operations, the kill flag is checked after each block read and
     after each updated or deleted row. If the kill flag is set, the
     statement is aborted. Note that if you are not using transactions,
     the changes are not rolled back.

   * `GET_LOCK()' aborts and returns `NULL'.

   * An *Note `INSERT DELAYED': insert-delayed. thread quickly flushes
     (inserts) all rows it has in memory and then terminates.

   * If the thread is in the table lock handler (state: `Locked'), the
     table lock is quickly aborted.

   * If the thread is waiting for free disk space in a write call, the
     write is aborted with a `disk full' error message.

   * *Warning*:

     Killing a *Note `REPAIR TABLE': repair-table. or *Note `OPTIMIZE
     TABLE': optimize-table. operation on a `MyISAM' table results in a
     table that is corrupted and unusable. Any reads or writes to such a
     table fail until you optimize or repair it again (without
     interruption).


File: manual.info,  Node: load-index,  Next: reset,  Prev: kill,  Up: other-administrative-sql

13.7.6.4 `LOAD INDEX INTO CACHE' Syntax
.......................................

     LOAD INDEX INTO CACHE
       TBL_INDEX_LIST [, TBL_INDEX_LIST] ...

     TBL_INDEX_LIST:
       TBL_NAME
         [[INDEX|KEY] (INDEX_NAME[, INDEX_NAME] ...)]
         [IGNORE LEAVES]

The *Note `LOAD INDEX INTO CACHE': load-index. statement preloads a
table index into the key cache to which it has been assigned by an
explicit *Note `CACHE INDEX': cache-index. statement, or into the
default key cache otherwise.  *Note `LOAD INDEX INTO CACHE':
load-index. is used only for `MyISAM' tables.

The `IGNORE LEAVES' modifier causes only blocks for the nonleaf nodes
of the index to be preloaded.

The following statement preloads nodes (index blocks) of indexes for
the tables `t1' and `t2':

     mysql> LOAD INDEX INTO CACHE t1, t2 IGNORE LEAVES;
     +---------+--------------+----------+----------+
     | Table   | Op           | Msg_type | Msg_text |
     +---------+--------------+----------+----------+
     | test.t1 | preload_keys | status   | OK       |
     | test.t2 | preload_keys | status   | OK       |
     +---------+--------------+----------+----------+

This statement preloads all index blocks from `t1'. It preloads only
blocks for the nonleaf nodes from `t2'.

The syntax of *Note `LOAD INDEX INTO CACHE': load-index. enables you to
specify that only particular indexes from a table should be preloaded.
The current implementation preloads all the table's indexes into the
cache, so there is no reason to specify anything other than the table
name.

*Note `LOAD INDEX INTO CACHE ... IGNORE LEAVES': load-index. fails
unless all indexes in a table have the same block size. (Prior to MySQL
5.0.87, it fails even without `IGNORE LEAVES'.) You can determine index
block sizes for a table by using *Note `myisamchk -dv': myisamchk. and
checking the `Blocksize' column.


File: manual.info,  Node: reset,  Prev: load-index,  Up: other-administrative-sql

13.7.6.5 `RESET' Syntax
.......................

     RESET RESET_OPTION [, RESET_OPTION] ...

The *Note `RESET': reset. statement is used to clear the state of
various server operations. You must have the `RELOAD' privilege to
execute *Note `RESET': reset.

*Note `RESET': reset. acts as a stronger version of the *Note `FLUSH':
flush. statement. See *Note flush::.

RESET_OPTION can be any of the following:

   * `MASTER'

     Deletes all binary logs listed in the index file, resets the
     binary log index file to be empty, and creates a new binary log
     file.

   * `QUERY CACHE'

     Removes all query results from the query cache.

   * `SLAVE'

     Makes the slave forget its replication position in the master
     binary logs. Also resets the relay log by deleting any existing
     relay log files and beginning a new one.


File: manual.info,  Node: sql-syntax-utility,  Prev: sql-syntax-server-administration,  Up: sql-syntax

13.8 MySQL Utility Statements
=============================

* Menu:

* describe::                     `DESCRIBE' Syntax
* explain::                      `EXPLAIN' Syntax
* help::                         `HELP' Syntax
* use::                          `USE' Syntax


File: manual.info,  Node: describe,  Next: explain,  Prev: sql-syntax-utility,  Up: sql-syntax-utility

13.8.1 `DESCRIBE' Syntax
------------------------

     {DESCRIBE | DESC} TBL_NAME [COL_NAME | WILD]

*Note `DESCRIBE': describe. provides information about the columns in a
table. It is a shortcut for `SHOW COLUMNS FROM'. As of MySQL 5.0.1,
these statements also display information for views. (See *Note
show-columns::.)

COL_NAME can be a column name, or a string containing the SQL ``%'' and
``_'' wildcard characters to obtain output only for the columns with
names matching the string. There is no need to enclose the string
within quotation marks unless it contains spaces or other special
characters.

     mysql> DESCRIBE City;
     +------------+----------+------+-----+---------+----------------+
     | Field      | Type     | Null | Key | Default | Extra          |
     +------------+----------+------+-----+---------+----------------+
     | Id         | int(11)  | NO   | PRI | NULL    | auto_increment |
     | Name       | char(35) | NO   |     |         |                |
     | Country    | char(3)  | NO   | UNI |         |                |
     | District   | char(20) | YES  | MUL |         |                |
     | Population | int(11)  | NO   |     | 0       |                |
     +------------+----------+------+-----+---------+----------------+
     5 rows in set (0.00 sec)

The description for *Note `SHOW COLUMNS': show-columns.  provides more
information about the output columns (see *Note show-columns::).

If the data types differ from what you expect them to be based on a
*Note `CREATE TABLE': create-table. statement, note that MySQL
sometimes changes data types when you create or alter a table. The
conditions under which this occurs are described in *Note
silent-column-changes::.

The *Note `DESCRIBE': describe. statement is provided for compatibility
with Oracle.

The *Note `SHOW CREATE TABLE': show-create-table, *Note `SHOW TABLE
STATUS': show-table-status, and *Note `SHOW INDEX': show-index.
statements also provide information about tables. See *Note show::.


File: manual.info,  Node: explain,  Next: help,  Prev: describe,  Up: sql-syntax-utility

13.8.2 `EXPLAIN' Syntax
-----------------------

     EXPLAIN [EXTENDED] SELECT SELECT_OPTIONS

Or:

     EXPLAIN TBL_NAME

The *Note `EXPLAIN': explain. statement can be used either as a way to
obtain information about how MySQL executes a statement, or as a
synonym for *Note `DESCRIBE': describe.:

   * When you precede a *Note `SELECT': select.  statement with the
     keyword *Note `EXPLAIN': explain, MySQL displays information from
     the optimizer about the query execution plan.  That is, MySQL
     explains how it would process the statement, including information
     about how tables are joined and in which order. *Note `EXPLAIN
     EXTENDED': explain. can be used to provide additional information.

     For information about using *Note `EXPLAIN': explain. and *Note
     `EXPLAIN EXTENDED': explain. to obtain query execution plan
     information, see *Note using-explain::.

   * *Note `EXPLAIN TBL_NAME': explain. is synonymous with `DESCRIBE
     TBL_NAME' or `SHOW COLUMNS FROM TBL_NAME'.  For information about
     *Note `DESCRIBE': describe.  and *Note `SHOW COLUMNS':
     show-columns, see *Note describe::, and *Note show-columns::.


File: manual.info,  Node: help,  Next: use,  Prev: explain,  Up: sql-syntax-utility

13.8.3 `HELP' Syntax
--------------------

     HELP 'SEARCH_STRING'

The *Note `HELP': help. statement returns online information from the
MySQL Reference manual. Its proper operation requires that the help
tables in the `mysql' database be initialized with help topic
information (see *Note server-side-help-support::).

The *Note `HELP': help. statement searches the help tables for the
given search string and displays the result of the search. The search
string is not case sensitive.

The HELP statement understands several types of search strings:

   * At the most general level, use `contents' to retrieve a list of
     the top-level help categories:

          HELP 'contents'

   * For a list of topics in a given help category, such as `Data
     Types', use the category name:

          HELP 'data types'

   * For help on a specific help topic, such as the `ASCII()' function
     or the *Note `CREATE TABLE': create-table. statement, use the
     associated keyword or keywords:

          HELP 'ascii'
          HELP 'create table'

In other words, the search string matches a category, many topics, or a
single topic. You cannot necessarily tell in advance whether a given
search string will return a list of items or the help information for a
single help topic. However, you can tell what kind of response *Note
`HELP': help. returned by examining the number of rows and columns in
the result set.

The following descriptions indicate the forms that the result set can
take. Output for the example statements is shown using the familiar
`tabular' or `vertical' format that you see when using the *Note
`mysql': mysql. client, but note that *Note `mysql': mysql. itself
reformats *Note `HELP': help. result sets in a different way.

   * Empty result set

     No match could be found for the search string.

   * Result set containing a single row with three columns

     This means that the search string yielded a hit for the help
     topic. The result has three columns:

        * `name': The topic name.

        * `description': Descriptive help text for the topic.

        * `example': Usage example or examples.  This column might be
          blank.

     Example: `HELP 'replace''

     Yields:

          name: REPLACE
          description: Syntax:
          REPLACE(str,from_str,to_str)

          Returns the string str with all occurrences of the string from_str
          replaced by the string to_str. REPLACE() performs a case-sensitive
          match when searching for from_str.
          example: mysql> SELECT REPLACE('www.mysql.com', 'w', 'Ww');
                  -> 'WwWwWw.mysql.com'

   * Result set containing multiple rows with two columns

     This means that the search string matched many help topics.  The
     result set indicates the help topic names:

        * `name': The help topic name.

        * `is_it_category': `Y' if the name represents a help category,
          `N' if it does not. If it does not, the `name' value when
          specified as the argument to the *Note `HELP': help.
          statement should yield a single-row result set containing a
          description for the named item.

     Example: `HELP 'status''

     Yields:

          +-----------------------+----------------+
          | name                  | is_it_category |
          +-----------------------+----------------+
          | SHOW                  | N              |
          | SHOW ENGINE           | N              |
          | SHOW INNODB STATUS    | N              |
          | SHOW MASTER STATUS    | N              |
          | SHOW PROCEDURE STATUS | N              |
          | SHOW SLAVE STATUS     | N              |
          | SHOW STATUS           | N              |
          | SHOW TABLE STATUS     | N              |
          +-----------------------+----------------+

   * Result set containing multiple rows with three columns

     This means the search string matches a category. The result set
     contains category entries:

        * `source_category_name': The help category name.

        * `name': The category or topic name

        * `is_it_category': `Y' if the name represents a help category,
          `N' if it does not. If it does not, the `name' value when
          specified as the argument to the *Note `HELP': help.
          statement should yield a single-row result set containing a
          description for the named item.

     Example: `HELP 'functions''

     Yields:

          +----------------------+-------------------------+----------------+
          | source_category_name | name                    | is_it_category |
          +----------------------+-------------------------+----------------+
          | Functions            | CREATE FUNCTION         | N              |
          | Functions            | DROP FUNCTION           | N              |
          | Functions            | Bit Functions           | Y              |
          | Functions            | Comparison operators    | Y              |
          | Functions            | Control flow functions  | Y              |
          | Functions            | Date and Time Functions | Y              |
          | Functions            | Encryption Functions    | Y              |
          | Functions            | Information Functions   | Y              |
          | Functions            | Logical operators       | Y              |
          | Functions            | Miscellaneous Functions | Y              |
          | Functions            | Numeric Functions       | Y              |
          | Functions            | String Functions        | Y              |
          +----------------------+-------------------------+----------------+

If you intend to use the *Note `HELP': help.  statement while other
tables are locked with *Note `LOCK TABLES': lock-tables, you must also
lock the required `mysql.help_XXX' tables.


File: manual.info,  Node: use,  Prev: help,  Up: sql-syntax-utility

13.8.4 `USE' Syntax
-------------------

     USE DB_NAME

The `USE DB_NAME' statement tells MySQL to use the DB_NAME database as
the default (current) database for subsequent statements. The database
remains the default until the end of the session or another *Note
`USE': use. statement is issued:

     USE db1;
     SELECT COUNT(*) FROM mytable;   # selects from db1.mytable
     USE db2;
     SELECT COUNT(*) FROM mytable;   # selects from db2.mytable

Making a particular database the default by means of the *Note `USE':
use. statement does not preclude you from accessing tables in other
databases. The following example accesses the `author' table from the
`db1' database and the `editor' table from the `db2' database:

     USE db1;
     SELECT author_name,editor_name FROM author,db2.editor
       WHERE author.editor_id = db2.editor.editor_id;

The *Note `USE': use. statement is provided for compatibility with
Sybase.


File: manual.info,  Node: storage-engines,  Next: ha-overview,  Prev: sql-syntax,  Up: Top

14 Storage Engines
******************

* Menu:

* myisam-storage-engine::        The `MyISAM' Storage Engine
* innodb-storage-engine::        The `InnoDB' Storage Engine
* merge-storage-engine::         The `MERGE' Storage Engine
* memory-storage-engine::        The `MEMORY' (`HEAP') Storage Engine
* bdb-storage-engine::           The `BDB' (`BerkeleyDB') Storage Engine
* example-storage-engine::       The `EXAMPLE' Storage Engine
* federated-storage-engine::     The `FEDERATED' Storage Engine
* archive-storage-engine::       The `ARCHIVE' Storage Engine
* csv-storage-engine::           The `CSV' Storage Engine
* blackhole-storage-engine::     The `BLACKHOLE' Storage Engine

MySQL supports several storage engines that act as handlers for
different table types. MySQL storage engines include both those that
handle transaction-safe tables and those that handle
nontransaction-safe tables:

   * `MyISAM' manages nontransactional tables. It provides high-speed
     storage and retrieval, as well as fulltext searching capabilities.
     `MyISAM' is supported in all MySQL configurations, and is the
     default storage engine unless you have configured MySQL to use a
     different one by default.

   * The `MEMORY' storage engine provides in-memory tables. The `MERGE'
     storage engine enables a collection of identical `MyISAM' tables
     to be handled as a single table. Like `MyISAM', the `MEMORY' and
     `MERGE' storage engines handle nontransactional tables, and both
     are also included in MySQL by default.

     *Note*:

     The `MEMORY' storage engine formerly was known as the `HEAP'
     engine.

   * The `InnoDB' and `BDB' storage engines provide transaction-safe
     tables. To maintain data integrity, `InnoDB' also supports
     `FOREIGN KEY' referential-integrity constraints.

   * The `EXAMPLE' storage engine is a `stub' engine that does nothing.
     You can create tables with this engine, but no data can be stored
     in them or retrieved from them. The purpose of this engine is to
     serve as an example in the MySQL source code that illustrates how
     to begin writing new storage engines. As such, it is primarily of
     interest to developers.

   * *Note `NDBCLUSTER': mysql-cluster. (also known as *Note `NDB':
     mysql-cluster.) is the storage engine used by MySQL Cluster to
     implement tables that are partitioned over many computers. It is
     available in MySQL 5.0 binary distributions. This storage engine
     is currently supported on a number of Unix platforms. Experimental
     support for Windows is available beginning in MySQL Cluster NDB
     7.0; however, we do not intend to backport this functionality to
     MySQL 5.0.

     MySQL Cluster is covered in a separate chapter of this Manual.
     See *Note mysql-cluster::, for more information.

     *Note*:

     MySQL Cluster users wishing to upgrade from MySQL 5.0 should
     instead migrate to MySQL Cluster NDB 6.3, 7.0, or 7.1; these are
     based on MySQL 5.1 but contain the latest improvements and fixes
     for *Note `NDBCLUSTER': mysql-cluster. The *Note `NDBCLUSTER':
     mysql-cluster. storage engine is not supported in standard MySQL
     5.1 releases.

   * The `ARCHIVE' storage engine is used for storing large amounts of
     data without indexes with a very small footprint.

   * The `CSV' storage engine stores data in text files using
     comma-separated values format.

   * The `BLACKHOLE' storage engine accepts but does not store data and
     retrievals always return an empty set.

   * The `FEDERATED' storage engine was added in MySQL 5.0.3. This
     engine stores data in a remote database.  Currently, it works with
     MySQL only, using the MySQL C Client API. In future releases, we
     intend to enable it to connect to other data sources using other
     drivers or client connection methods.

To determine which storage engines your server supports by using the
*Note `SHOW ENGINES': show-engines. statement. The value in the
`Support' column indicates whether an engine can be used. A value of
`YES', `NO', or `DEFAULT' indicates that an engine is available, not
available, or available and currently set as the default storage engine.

     mysql> SHOW ENGINES\G
     *************************** 1. row ***************************
      Engine: MyISAM
     Support: DEFAULT
     Comment: Default engine as of MySQL 3.23 with great performance
     *************************** 2. row ***************************
      Engine: MEMORY
     Support: YES
     Comment: Hash based, stored in memory, useful for temporary tables
     *************************** 3. row ***************************
      Engine: InnoDB
     Support: YES
     Comment: Supports transactions, row-level locking, and foreign keys
     *************************** 4. row ***************************
      Engine: BerkeleyDB
     Support: NO
     Comment: Supports transactions and page-level locking
     *************************** 5. row ***************************
      Engine: BLACKHOLE
     Support: YES
     Comment: /dev/null storage engine (anything you write to it disappears)
     ...

This chapter describes each of the MySQL storage engines except for
*Note `NDBCLUSTER': mysql-cluster, which is covered in *Note
mysql-cluster::.

For information about storage engine support offered in commercial
MySQL Server binaries, see `MySQL Enterprise Server 5.1'
(http://www.mysql.com/products/enterprise/server.html), on the MySQL
Web site.  The storage engines available might depend on which edition
of Enterprise Server you are using.

For answers to some commonly asked questions about MySQL storage
engines, see *Note faqs-storage-engines::.

When you create a new table, you can specify which storage engine to
use by adding an `ENGINE' or `TYPE' table option to the *Note `CREATE
TABLE': create-table. statement:

     CREATE TABLE t (i INT) ENGINE = INNODB;
     CREATE TABLE t (i INT) TYPE = MEMORY;

The older term `TYPE' is supported as a synonym for `ENGINE' for
backward compatibility, but `ENGINE' is the preferred term and `TYPE'
is deprecated.

If you omit the `ENGINE' or `TYPE' option, the default storage engine
is used. Normally, this is `MyISAM', but you can change it by using the
`--default-storage-engine' or `--default-table-type' server startup
option, or by setting the `default-storage-engine' or
`default-table-type' option in the `my.cnf' configuration file.

You can set the default storage engine to be used during the current
session by setting the `storage_engine' or `table_type' variable:

     SET storage_engine=MYISAM;
     SET table_type=BDB;

When MySQL is installed on Windows using the MySQL Configuration
Wizard, the `InnoDB' or `MyISAM' storage engine can be selected as the
default. See *Note mysql-config-wizard-database-usage::.

To convert a table from one storage engine to another, use an *Note
`ALTER TABLE': alter-table. statement that indicates the new engine:

     ALTER TABLE t ENGINE = MYISAM;
     ALTER TABLE t TYPE = BDB;

See *Note create-table::, and *Note alter-table::.

If you try to use a storage engine that is not compiled in or that is
compiled in but deactivated, MySQL instead creates a table using the
default storage engine. This behavior is convenient when you want to
copy tables between MySQL servers that support different storage
engines. (For example, in a replication setup, perhaps your master
server supports transactional storage engines for increased safety, but
the slave servers use only nontransactional storage engines for greater
speed.)

This automatic substitution of the default storage engine for
unavailable engines can be confusing for new MySQL users. A warning is
generated whenever a storage engine is automatically changed.

For new tables, MySQL always creates an `.frm' file to hold the table
and column definitions. The table's index and data may be stored in one
or more other files, depending on the storage engine. The server
creates the `.frm' file above the storage engine level. Individual
storage engines create any additional files required for the tables
that they manage.

A database may contain tables of different types. That is, tables need
not all be created with the same storage engine.

Transaction-safe tables (TSTs) have several advantages over
nontransaction-safe tables (NTSTs):

   * They are safer. Even if MySQL crashes or you get hardware
     problems, you can get your data back, either by automatic recovery
     or from a backup plus the transaction log.

   * You can combine many statements and accept them all at the same
     time with the *Note `COMMIT': commit. statement (if autocommit is
     disabled).

   * You can execute *Note `ROLLBACK': commit. to ignore your changes
     (if autocommit is disabled).

   * If an update fails, all of your changes are reverted. (With
     nontransaction-safe tables, all changes that have taken place are
     permanent.)

   * Transaction-safe storage engines can provide better concurrency
     for tables that get many updates concurrently with reads.

You can combine transaction-safe and nontransaction-safe tables in the
same statements to get the best of both worlds. However, although MySQL
supports several transaction-safe storage engines, for best results,
you should not mix different storage engines within a transaction with
autocommit disabled. For example, if you do this, changes to
nontransaction-safe tables still are committed immediately and cannot
be rolled back. For information about this and other problems that can
occur in transactions that use mixed storage engines, see *Note
commit::.

Nontransaction-safe tables have several advantages of their own, all of
which occur because there is no transaction overhead:

   * Much faster

   * Lower disk space requirements

   * Less memory required to perform updates


File: manual.info,  Node: myisam-storage-engine,  Next: innodb-storage-engine,  Prev: storage-engines,  Up: storage-engines

14.1 The `MyISAM' Storage Engine
================================

* Menu:

* myisam-start::                 `MyISAM' Startup Options
* key-space::                    Space Needed for Keys
* myisam-table-formats::         `MyISAM' Table Storage Formats
* myisam-table-problems::        `MyISAM' Table Problems

`MyISAM' is the default storage engine. It is based on the older (and
no longer available) `ISAM' storage engine but has many useful
extensions.

Each `MyISAM' table is stored on disk in three files. The files have
names that begin with the table name and have an extension to indicate
the file type. An `.frm' file stores the table format. The data file
has an `.MYD' (`MYData') extension. The index file has an `.MYI'
(`MYIndex') extension.

To specify explicitly that you want a `MyISAM' table, indicate that
with an `ENGINE' table option:

     CREATE TABLE t (i INT) ENGINE = MYISAM;

The older term `TYPE' is supported as a synonym for `ENGINE' for
backward compatibility, but `ENGINE' is the preferred term and `TYPE'
is deprecated.

Normally, it is unnecessary to use `ENGINE' to specify the `MyISAM'
storage engine.  `MyISAM' is the default engine unless the default has
been changed. To ensure that `MyISAM' is used in situations where the
default might have been changed, include the `ENGINE' option explicitly.

You can check or repair `MyISAM' tables with the *Note `mysqlcheck':
mysqlcheck. client or *Note `myisamchk': myisamchk.  utility. You can
also compress `MyISAM' tables with *Note `myisampack': myisampack. to
take up much less space. See *Note mysqlcheck::, *Note myisamchk::, and
*Note myisampack::.

`MyISAM' tables have the following characteristics:

   * All data values are stored with the low byte first. This makes the
     data machine and operating system independent. The only
     requirements for binary portability are that the machine uses
     two's-complement signed integers and IEEE floating-point format.
     These requirements are widely used among mainstream machines.
     Binary compatibility might not be applicable to embedded systems,
     which sometimes have peculiar processors.

     There is no significant speed penalty for storing data low byte
     first; the bytes in a table row normally are unaligned and it
     takes little more processing to read an unaligned byte in order
     than in reverse order. Also, the code in the server that fetches
     column values is not time critical compared to other code.

   * All numeric key values are stored with the high byte first to
     permit better index compression.

   * Large files (up to 63-bit file length) are supported on file
     systems and operating systems that support large files.

   * There is a limit of 2^32 (~4.295E+09) rows in a `MyISAM' table. If
     you build MySQL with the `--with-big-tables' option, the row
     limitation is increased to (2^32)^2 (1.844E+19) rows. See *Note
     source-configuration-options::. Binary distributions for Unix and
     Linux are built with this option.

   * The maximum number of indexes per `MyISAM' table is 64. This can
     be changed by recompiling. Beginning with MySQL 5.0.18, you can
     configure the build by invoking `configure' with the
     `--with-max-indexes=N' option, where N is the maximum number of
     indexes to permit per `MyISAM' table.  N must be less than or
     equal to 128.  Before MySQL 5.0.18, you must change the source.

     The maximum number of columns per index is 16.

   * The maximum key length is 1000 bytes. This can also be changed by
     changing the source and recompiling. For the case of a key longer
     than 250 bytes, a larger key block size than the default of 1024
     bytes is used.

   * When rows are inserted in sorted order (as when you are using an
     `AUTO_INCREMENT' column), the index tree is split so that the high
     node only contains one key. This improves space utilization in the
     index tree.

   * Internal handling of one `AUTO_INCREMENT' column per table is
     supported. `MyISAM' automatically updates this column for *Note
     `INSERT': insert. and *Note `UPDATE': update. operations. This
     makes `AUTO_INCREMENT' columns faster (at least 10%).  Values at
     the top of the sequence are not reused after being deleted. (When
     an `AUTO_INCREMENT' column is defined as the last column of a
     multiple-column index, reuse of values deleted from the top of a
     sequence does occur.) The `AUTO_INCREMENT' value can be reset with
     *Note `ALTER TABLE': alter-table. or *Note `myisamchk': myisamchk.

   * Dynamic-sized rows are much less fragmented when mixing deletes
     with updates and inserts. This is done by automatically combining
     adjacent deleted blocks and by extending blocks if the next block
     is deleted.

   * `MyISAM' supports concurrent inserts: If a table has no free
     blocks in the middle of the data file, you can *Note `INSERT':
     insert. new rows into it at the same time that other threads are
     reading from the table. A free block can occur as a result of
     deleting rows or an update of a dynamic length row with more data
     than its current contents.  When all free blocks are used up
     (filled in), future inserts become concurrent again. See *Note
     concurrent-inserts::.

   * You can put the data file and index file in different directories
     on different physical devices to get more speed with the `DATA
     DIRECTORY' and `INDEX DIRECTORY' table options to *Note `CREATE
     TABLE': create-table. See *Note create-table::.

   * *Note `BLOB': blob. and *Note `TEXT': blob. columns can be indexed.

   * `NULL' values are permitted in indexed columns.  This takes 0 to 1
     bytes per key.

   * Each character column can have a different character set. See
     *Note charset::.

   * There is a flag in the `MyISAM' index file that indicates whether
     the table was closed correctly. If *Note `mysqld': mysqld. is
     started with the `--myisam-recover' option, `MyISAM' tables are
     automatically checked when opened, and are repaired if the table
     wasn't closed properly.

   * *Note `myisamchk': myisamchk. marks tables as checked if you run
     it with the `--update-state' option. *Note `myisamchk --fast':
     myisamchk. checks only those tables that don't have this mark.

   * *Note `myisamchk --analyze': myisamchk. stores statistics for
     portions of keys, as well as for entire keys.

   * *Note `myisampack': myisampack. can pack *Note `BLOB': blob. and
     *Note `VARCHAR': char. columns.

`MyISAM' also supports the following features:

   * Support for a true *Note `VARCHAR': char. type; a *Note `VARCHAR':
     char. column starts with a length stored in one or two bytes.

   * Tables with *Note `VARCHAR': char. columns may have fixed or
     dynamic row length.

   * The sum of the lengths of the *Note `VARCHAR': char. and *Note
     `CHAR': char. columns in a table may be up to 64KB.

   * Arbitrary length `UNIQUE' constraints.

* Additional Resources *

   * A forum dedicated to the `MyISAM' storage engine is available at
     `http://forums.mysql.com/list.php?21'.


File: manual.info,  Node: myisam-start,  Next: key-space,  Prev: myisam-storage-engine,  Up: myisam-storage-engine

14.1.1 `MyISAM' Startup Options
-------------------------------

The following options to *Note `mysqld': mysqld. can be used to change
the behavior of `MyISAM' tables. For additional information, see *Note
server-options::.

*MyISAM Option/Variable Reference*

Name           Cmd-Line    Option file System Var  Status Var  Var Scope   Dynamic
bulk_insert_buffer_sizeYes         Yes         Yes                     Both        Yes
concurrent_insertYes         Yes         Yes                     Global      Yes
delay-key-writeYes         Yes                                 Global      Yes
- _Variable_:                          Yes                     Global      Yes
delay_key_write                                                            
have_rtree_keys                        Yes                     Global      No
key_buffer_sizeYes         Yes         Yes                     Global      Yes
log-isam       Yes         Yes                                             
myisam-block-sizeYes         Yes                                             
myisam_data_pointer_sizeYes         Yes         Yes                     Global      Yes
myisam_max_extra_sort_file_sizeYes         Yes         Yes                     Global      No
myisam_max_sort_file_sizeYes         Yes         Yes                     Global      Yes
myisam_mmap_sizeYes         Yes         Yes                     Global      No
myisam-recover Yes         Yes                                             
- _Variable_:                                                              
myisam_recover_options                                                            
myisam_recover_options                        Yes                     Global      No
myisam_repair_threadsYes         Yes         Yes                     Both        Yes
myisam_sort_buffer_sizeYes         Yes         Yes                     Both        Yes
myisam_stats_methodYes         Yes         Yes                     Both        Yes
skip-concurrent-insertYes         Yes                                             
- _Variable_:                                                              
concurrent_insert                                                            
tmp_table_size Yes         Yes         Yes                     Both        Yes

   * `--myisam-recover=MODE'

     Set the mode for automatic recovery of crashed `MyISAM' tables.

   * `--delay-key-write=ALL'

     Don't flush key buffers between writes for any `MyISAM' table.

     *Note*:

     If you do this, you should not access `MyISAM' tables from another
     program (such as from another MySQL server or with *Note
     `myisamchk': myisamchk.) when the tables are in use.  Doing so
     risks index corruption. Using `--external-locking' does not
     eliminate this risk.

The following system variables affect the behavior of `MyISAM' tables.
For additional information, see *Note server-system-variables::.

   * `bulk_insert_buffer_size'

     The size of the tree cache used in bulk insert optimization.

     *Note*:

     This is a limit _per thread_!

   * `myisam_max_sort_file_size'

     The maximum size of the temporary file that MySQL is permitted to
     use while re-creating a `MyISAM' index (during *Note `REPAIR
     TABLE': repair-table, *Note `ALTER TABLE': alter-table, or *Note
     `LOAD DATA INFILE': load-data.). If the file size would be larger
     than this value, the index is created using the key cache instead,
     which is slower. The value is given in bytes.

   * `myisam_sort_buffer_size'

     Set the size of the buffer used when recovering tables.

Automatic recovery is activated if you start *Note `mysqld': mysqld.
with the `--myisam-recover' option. In this case, when the server opens
a `MyISAM' table, it checks whether the table is marked as crashed or
whether the open count variable for the table is not 0 and you are
running the server with external locking disabled. If either of these
conditions is true, the following happens:

   * The server checks the table for errors.

   * If the server finds an error, it tries to do a fast table repair
     (with sorting and without re-creating the data file).

   * If the repair fails because of an error in the data file (for
     example, a duplicate-key error), the server tries again, this time
     re-creating the data file.

   * If the repair still fails, the server tries once more with the old
     repair option method (write row by row without sorting).  This
     method should be able to repair any type of error and has low disk
     space requirements.

If the recovery wouldn't be able to recover all rows from previously
completed statements and you didn't specify `FORCE' in the value of the
`--myisam-recover' option, automatic repair aborts with an error
message in the error log:

     Error: Couldn't repair table: test.g00pages

If you specify `FORCE', a warning like this is written instead:

     Warning: Found 344 of 354 rows when repairing ./test/g00pages

Note that if the automatic recovery value includes `BACKUP', the
recovery process creates files with names of the form
`TBL_NAME-DATETIME.BAK'.  You should have a `cron' script that
automatically moves these files from the database directories to backup
media.


File: manual.info,  Node: key-space,  Next: myisam-table-formats,  Prev: myisam-start,  Up: myisam-storage-engine

14.1.2 Space Needed for Keys
----------------------------

`MyISAM' tables use B-tree indexes. You can roughly calculate the size
for the index file as `(key_length+4)/0.67', summed over all keys. This
is for the worst case when all keys are inserted in sorted order and
the table doesn't have any compressed keys.

String indexes are space compressed. If the first index part is a
string, it is also prefix compressed. Space compression makes the index
file smaller than the worst-case figure if a string column has a lot of
trailing space or is a *Note `VARCHAR': char. column that is not always
used to the full length. Prefix compression is used on keys that start
with a string. Prefix compression helps if there are many strings with
an identical prefix.

In `MyISAM' tables, you can also prefix compress numbers by specifying
the `PACK_KEYS=1' table option when you create the table. Numbers are
stored with the high byte first, so this helps when you have many
integer keys that have an identical prefix.


File: manual.info,  Node: myisam-table-formats,  Next: myisam-table-problems,  Prev: key-space,  Up: myisam-storage-engine

14.1.3 `MyISAM' Table Storage Formats
-------------------------------------

* Menu:

* static-format::                Static (Fixed-Length) Table Characteristics
* dynamic-format::               Dynamic Table Characteristics
* compressed-format::            Compressed Table Characteristics

`MyISAM' supports three different storage formats. Two of them, fixed
and dynamic format, are chosen automatically depending on the type of
columns you are using. The third, compressed format, can be created
only with the *Note `myisampack': myisampack. utility (see *Note
myisampack::).

When you use *Note `CREATE TABLE': create-table. or *Note `ALTER
TABLE': alter-table. for a table that has no *Note `BLOB': blob. or
*Note `TEXT': blob. columns, you can force the table format to *Note
`FIXED': numeric-types. or `DYNAMIC' with the `ROW_FORMAT' table option.

See *Note create-table::, for information about `ROW_FORMAT'.

You can decompress (unpack) compressed `MyISAM' tables using *Note
`myisamchk `--unpack'': myisamchk.; see *Note myisamchk::, for more
information.


File: manual.info,  Node: static-format,  Next: dynamic-format,  Prev: myisam-table-formats,  Up: myisam-table-formats

14.1.3.1 Static (Fixed-Length) Table Characteristics
....................................................

Static format is the default for `MyISAM' tables. It is used when the
table contains no variable-length columns (*Note `VARCHAR': char, *Note
`VARBINARY': binary-varbinary, *Note `BLOB': blob, or *Note `TEXT':
blob.). Each row is stored using a fixed number of bytes.

Of the three `MyISAM' storage formats, static format is the simplest
and most secure (least subject to corruption). It is also the fastest
of the on-disk formats due to the ease with which rows in the data file
can be found on disk: To look up a row based on a row number in the
index, multiply the row number by the row length to calculate the row
position. Also, when scanning a table, it is very easy to read a
constant number of rows with each disk read operation.

The security is evidenced if your computer crashes while the MySQL
server is writing to a fixed-format `MyISAM' file. In this case, *Note
`myisamchk': myisamchk. can easily determine where each row starts and
ends, so it can usually reclaim all rows except the partially written
one. Note that `MyISAM' table indexes can always be reconstructed based
on the data rows.

*Note*:

Fixed-length row format is only available for tables without *Note
`BLOB': blob. or *Note `TEXT': blob. columns. Creating a table with
these columns with an explicit `ROW_FORMAT' clause will not raise an
error or warning; the format specification will be ignored.

Static-format tables have these characteristics:

   * *Note `CHAR': char. and *Note `VARCHAR': char. columns are
     space-padded to the specified column width, although the column
     type is not altered. This is also true for *Note `NUMERIC':
     numeric-types. and *Note `DECIMAL': numeric-types. columns created
     before MySQL 5.0.3. *Note `BINARY': binary-varbinary.  and *Note
     `VARBINARY': binary-varbinary. columns are space-padded to the
     column width before MySQL 5.0.15. As of 5.0.15, *Note `BINARY':
     binary-varbinary. and *Note `VARBINARY': binary-varbinary. columns
     are padded with `0x00' bytes.

   * Very quick.

   * Easy to cache.

   * Easy to reconstruct after a crash, because rows are located in
     fixed positions.

   * Reorganization is unnecessary unless you delete a huge number of
     rows and want to return free disk space to the operating system.
     To do this, use *Note `OPTIMIZE TABLE': optimize-table. or *Note
     `myisamchk -r': myisamchk.

   * Usually require more disk space than dynamic-format tables.


File: manual.info,  Node: dynamic-format,  Next: compressed-format,  Prev: static-format,  Up: myisam-table-formats

14.1.3.2 Dynamic Table Characteristics
......................................

Dynamic storage format is used if a `MyISAM' table contains any
variable-length columns (*Note `VARCHAR': char, *Note `VARBINARY':
binary-varbinary, *Note `BLOB': blob, or *Note `TEXT': blob.), or if
the table was created with the `ROW_FORMAT=DYNAMIC' table option.

Dynamic format is a little more complex than static format because each
row has a header that indicates how long it is. A row can become
fragmented (stored in noncontiguous pieces) when it is made longer as a
result of an update.

You can use *Note `OPTIMIZE TABLE': optimize-table. or *Note `myisamchk
-r': myisamchk. to defragment a table. If you have fixed-length columns
that you access or change frequently in a table that also contains some
variable-length columns, it might be a good idea to move the
variable-length columns to other tables just to avoid fragmentation.

Dynamic-format tables have these characteristics:

   * All string columns are dynamic except those with a length less
     than four.

   * Each row is preceded by a bitmap that indicates which columns
     contain the empty string (for string columns) or zero (for numeric
     columns). Note that this does not include columns that contain
     `NULL' values. If a string column has a length of zero after
     trailing space removal, or a numeric column has a value of zero,
     it is marked in the bitmap and not saved to disk. Nonempty strings
     are saved as a length byte plus the string contents.

   * Much less disk space usually is required than for fixed-length
     tables.

   * Each row uses only as much space as is required. However, if a row
     becomes larger, it is split into as many pieces as are required,
     resulting in row fragmentation. For example, if you update a row
     with information that extends the row length, the row becomes
     fragmented. In this case, you may have to run *Note `OPTIMIZE
     TABLE': optimize-table. or *Note `myisamchk -r': myisamchk. from
     time to time to improve performance. Use *Note `myisamchk -ei':
     myisamchk. to obtain table statistics.

   * More difficult than static-format tables to reconstruct after a
     crash, because rows may be fragmented into many pieces and links
     (fragments) may be missing.

   * The expected row length for dynamic-sized rows is calculated using
     the following expression:

          3
          + (NUMBER OF COLUMNS + 7) / 8
          + (NUMBER OF CHAR COLUMNS)
          + (PACKED SIZE OF NUMERIC COLUMNS)
          + (LENGTH OF STRINGS)
          + (NUMBER OF NULL COLUMNS + 7) / 8

     There is a penalty of 6 bytes for each link. A dynamic row is
     linked whenever an update causes an enlargement of the row. Each
     new link is at least 20 bytes, so the next enlargement probably
     goes in the same link. If not, another link is created. You can
     find the number of links using *Note `myisamchk -ed': myisamchk.
     All links may be removed with *Note `OPTIMIZE TABLE':
     optimize-table. or *Note `myisamchk -r': myisamchk.


File: manual.info,  Node: compressed-format,  Prev: dynamic-format,  Up: myisam-table-formats

14.1.3.3 Compressed Table Characteristics
.........................................

Compressed storage format is a read-only format that is generated with
the *Note `myisampack': myisampack. tool.  Compressed tables can be
uncompressed with *Note `myisamchk': myisamchk.

Compressed tables have the following characteristics:

   * Compressed tables take very little disk space. This minimizes disk
     usage, which is helpful when using slow disks (such as CD-ROMs).

   * Each row is compressed separately, so there is very little access
     overhead. The header for a row takes up one to three bytes
     depending on the biggest row in the table. Each column is
     compressed differently. There is usually a different Huffman tree
     for each column. Some of the compression types are:

        * Suffix space compression.

        * Prefix space compression.

        * Numbers with a value of zero are stored using one bit.

        * If values in an integer column have a small range, the column
          is stored using the smallest possible type. For example, a
          *Note `BIGINT': numeric-types. column (eight bytes) can be
          stored as a *Note `TINYINT': numeric-types. column (one byte)
          if all its values are in the range from `-128' to `127'.

        * If a column has only a small set of possible values, the data
          type is converted to *Note `ENUM': enum.

        * A column may use any combination of the preceding compression
          types.

   * Can be used for fixed-length or dynamic-length rows.

*Note*:

While a compressed table is read only, and you cannot therefore update
or add rows in the table, DDL (Data Definition Language) operations are
still valid. For example, you may still use `DROP' to drop the table,
and *Note `TRUNCATE TABLE': truncate-table. to empty the table.


File: manual.info,  Node: myisam-table-problems,  Prev: myisam-table-formats,  Up: myisam-storage-engine

14.1.4 `MyISAM' Table Problems
------------------------------

* Menu:

* corrupted-myisam-tables::      Corrupted `MyISAM' Tables
* myisam-table-close::           Problems from Tables Not Being Closed Properly

The file format that MySQL uses to store data has been extensively
tested, but there are always circumstances that may cause database
tables to become corrupted. The following discussion describes how this
can happen and how to handle it.


File: manual.info,  Node: corrupted-myisam-tables,  Next: myisam-table-close,  Prev: myisam-table-problems,  Up: myisam-table-problems

14.1.4.1 Corrupted `MyISAM' Tables
..................................

Even though the `MyISAM' table format is very reliable (all changes to
a table made by an SQL statement are written before the statement
returns), you can still get corrupted tables if any of the following
events occur:

   * The *Note `mysqld': mysqld. process is killed in the middle of a
     write.

   * An unexpected computer shutdown occurs (for example, the computer
     is turned off).

   * Hardware failures.

   * You are using an external program (such as *Note `myisamchk':
     myisamchk.) to modify a table that is being modified by the server
     at the same time.

   * A software bug in the MySQL or `MyISAM' code.

Typical symptoms of a corrupt table are:

   * You get the following error while selecting data from the table:

          Incorrect key file for table: '...'. Try to repair it

   * Queries don't find rows in the table or return incomplete results.

You can check the health of a `MyISAM' table using the *Note `CHECK
TABLE': check-table. statement, and repair a corrupted `MyISAM' table
with *Note `REPAIR TABLE': repair-table. When *Note `mysqld': mysqld.
is not running, you can also check or repair a table with the *Note
`myisamchk': myisamchk. command.  See *Note check-table::, *Note
repair-table::, and *Note myisamchk::.

If your tables become corrupted frequently, you should try to determine
why this is happening. The most important thing to know is whether the
table became corrupted as a result of a server crash. You can verify
this easily by looking for a recent `restarted mysqld' message in the
error log. If there is such a message, it is likely that table
corruption is a result of the server dying. Otherwise, corruption may
have occurred during normal operation. This is a bug. You should try to
create a reproducible test case that demonstrates the problem. See
*Note crashing::, and MySQL Internals: Porting
(http://forge.mysql.com/wiki/MySQL_Internals_Porting).


File: manual.info,  Node: myisam-table-close,  Prev: corrupted-myisam-tables,  Up: myisam-table-problems

14.1.4.2 Problems from Tables Not Being Closed Properly
.......................................................

Each `MyISAM' index file (`.MYI' file) has a counter in the header that
can be used to check whether a table has been closed properly. If you
get the following warning from *Note `CHECK TABLE': check-table. or
*Note `myisamchk': myisamchk, it means that this counter has gone out
of sync:

     clients are using or haven't closed the table properly

This warning doesn't necessarily mean that the table is corrupted, but
you should at least check the table.

The counter works as follows:

   * The first time a table is updated in MySQL, a counter in the
     header of the index files is incremented.

   * The counter is not changed during further updates.

   * When the last instance of a table is closed (because a *Note
     `FLUSH TABLES': flush. operation was performed or because there is
     no room in the table cache), the counter is decremented if the
     table has been updated at any point.

   * When you repair the table or check the table and it is found to be
     okay, the counter is reset to zero.

   * To avoid problems with interaction with other processes that might
     check the table, the counter is not decremented on close if it was
     zero.

In other words, the counter can become incorrect only under these
conditions:

   * A `MyISAM' table is copied without first issuing *Note `LOCK
     TABLES': lock-tables. and *Note `FLUSH TABLES': flush.

   * MySQL has crashed between an update and the final close.  (Note
     that the table may still be okay, because MySQL always issues
     writes for everything between each statement.)

   * A table was modified by *Note `myisamchk --recover': myisamchk. or
     *Note `myisamchk --update-state': myisamchk. at the same time that
     it was in use by *Note `mysqld': mysqld.

   * Multiple *Note `mysqld': mysqld. servers are using the table and
     one server performed a *Note `REPAIR TABLE': repair-table. or
     *Note `CHECK TABLE': check-table. on the table while it was in use
     by another server. In this setup, it is safe to use *Note `CHECK
     TABLE': check-table, although you might get the warning from other
     servers. However, *Note `REPAIR TABLE': repair-table. should be
     avoided because when one server replaces the data file with a new
     one, this is not known to the other servers.

     In general, it is a bad idea to share a data directory among
     multiple servers. See *Note multiple-servers::, for additional
     discussion.


File: manual.info,  Node: innodb-storage-engine,  Next: merge-storage-engine,  Prev: myisam-storage-engine,  Up: storage-engines

14.2 The `InnoDB' Storage Engine
================================

* Menu:

* innodb-contact-information::   `InnoDB' Contact Information
* innodb-configuration::         `InnoDB' Configuration
* innodb-parameters::            `InnoDB' Startup Options and System Variables
* using-innodb-tables::          Creating and Using `InnoDB' Tables
* innodb-data-log-reconfiguration::  Adding, Removing, or Resizing `InnoDB' Data and Log Files
* innodb-backup::                Backing Up and Recovering an `InnoDB' Database
* innodb-migration::             Moving an `InnoDB' Database to Another Machine
* innodb-transaction-model::     The `InnoDB' Transaction Model and Locking
* innodb-multi-versioning::      `InnoDB' Multi-Versioning
* innodb-table-and-index::       `InnoDB' Table and Index Structures
* innodb-disk-management::       `InnoDB' Disk I/O and File Space Management
* innodb-error-handling::        `InnoDB' Error Handling
* innodb-tuning-troubleshooting::  `InnoDB' Performance Tuning and Troubleshooting
* innodb-restrictions::          Limits on `InnoDB' Tables

`InnoDB' is a transaction-safe (ACID compliant) storage engine for
MySQL that has commit, rollback, and crash-recovery capabilities to
protect user data.  `InnoDB' row-level locking (without escalation to
coarser granularity locks) and Oracle-style consistent nonlocking reads
increase multi-user concurrency and performance.  `InnoDB' stores user
data in clustered indexes to reduce I/O for common queries based on
primary keys. To maintain data integrity, `InnoDB' also supports
`FOREIGN KEY' referential-integrity constraints.  You can freely mix
`InnoDB' tables with tables from other MySQL storage engines, even
within the same statement.

To determine whether your server supports `InnoDB' use the *Note `SHOW
ENGINES': show-engines. statement. See *Note show-engines::.

`InnoDB' has been designed for maximum performance when processing
large data volumes. Its CPU efficiency is probably not matched by any
other disk-based relational database engine.

The `InnoDB' storage engine maintains its own buffer pool for caching
data and indexes in main memory.  `InnoDB' stores its tables and
indexes in a tablespace, which may consist of several files (or raw disk
partitions). This is different from, for example, `MyISAM' tables where
each table is stored using separate files. `InnoDB' tables can be very
large even on operating systems where file size is limited to 2GB.

The Windows Essentials installer makes `InnoDB' the MySQL default
storage engine on Windows, if the server being installed supports
`InnoDB'.

`InnoDB' is used in production at numerous large database sites
requiring high performance. The famous Internet news site Slashdot.org
runs on `InnoDB'. Mytrix, Inc.  stores more than 1TB of data in
`InnoDB', and another site handles an average load of 800
inserts/updates per second in `InnoDB'.

`InnoDB' is published under the same GNU GPL License Version 2 (of June
1991) as MySQL. For more information on MySQL licensing, see
http://www.mysql.com/company/legal/licensing/.

* Additional Resources *

   * A forum dedicated to the `InnoDB' storage engine is available at
     `http://forums.mysql.com/list.php?22'.

   * Innobase Oy also hosts several forums, available at
     `http://forums.innodb.com'.

   * `InnoDB Hot Backup' enables you to back up a running MySQL
     database, including `InnoDB' and `MyISAM' tables, with minimal
     disruption to operations while producing a consistent snapshot of
     the database. When `InnoDB Hot Backup' is copying `InnoDB' tables,
     reads and writes to both `InnoDB' and `MyISAM' tables can
     continue. During the copying of `MyISAM' tables, reads (but not
     writes) to those tables are permitted. In addition, `InnoDB Hot
     Backup' supports creating compressed backup files, and performing
     backups of subsets of `InnoDB' tables. In conjunction with MySQL's
     binary log, users can perform point-in-time recovery.  `InnoDB Hot
     Backup' is commercially licensed by Innobase Oy. For a more
     complete description of `InnoDB Hot Backup', see
     `http://www.innodb.com/products/hot-backup/features/' or download
     the documentation from
     `http://www.innodb.com/doc/hot_backup/manual.html'.  You can order
     trial, term, and perpetual licenses from Innobase at
     `http://www.innodb.com/wp/products/hot-backup/order/'.


File: manual.info,  Node: innodb-contact-information,  Next: innodb-configuration,  Prev: innodb-storage-engine,  Up: innodb-storage-engine

14.2.1 `InnoDB' Contact Information
-----------------------------------

Contact information for Innobase Oy, producer of the `InnoDB' engine:

Web site: `http://www.innodb.com/'

Email: `innodb_sales_ww at oracle.com' or use this contact form:
`http://www.innodb.com/contact-form'

Phone:

     +358-9-6969 3250 (office, Heikki Tuuri)
     +358-40-5617367 (mobile, Heikki Tuuri)
     +358-40-5939732 (mobile, Satu Sire'n)

Address:

     Innobase Oy Inc.
     World Trade Center Helsinki
     Aleksanterinkatu 17
     P.O.Box 800
     00101 Helsinki
     Finland


File: manual.info,  Node: innodb-configuration,  Next: innodb-parameters,  Prev: innodb-contact-information,  Up: innodb-storage-engine

14.2.2 `InnoDB' Configuration
-----------------------------

* Menu:

* innodb-multiple-tablespaces::  Using Per-Table Tablespaces
* innodb-raw-devices::           Using Raw Devices for the Shared Tablespace
* innodb-init::                  Creating the `InnoDB' Tablespace
* error-creating-innodb::        Dealing with `InnoDB' Initialization Problems

If you do not want to use `InnoDB' tables, start the server with the
`--skip-innodb' option to disable the `InnoDB' storage engine. In this
case, the server will not start if the default storage engine is set to
*Note `InnoDB': innodb-storage-engine. Use `--default-storage-engine'
to set the default to some other engine if necessary.

*Caution*:

`InnoDB' is a transaction-safe (ACID compliant) storage engine for
MySQL that has commit, rollback, and crash-recovery capabilities to
protect user data.  *However, it cannot do so* if the underlying
operating system or hardware does not work as advertised. Many
operating systems or disk subsystems may delay or reorder write
operations to improve performance. On some operating systems, the very
`fsync()' system call that should wait until all unwritten data for a
file has been flushed might actually return before the data has been
flushed to stable storage. Because of this, an operating system crash
or a power outage may destroy recently committed data, or in the worst
case, even corrupt the database because of write operations having been
reordered. If data integrity is important to you, you should perform
some `pull-the-plug' tests before using anything in production. On Mac
OS X 10.3 and up, `InnoDB' uses a special `fcntl()' file flush method.
Under Linux, it is advisable to *disable the write-back cache*.

On ATA/SATA disk drives, a command such `hdparm -W0 /dev/hda' may work
to disable the write-back cache.  *Beware that some drives or disk
controllers may be unable to disable the write-back cache.*

Two important disk-based resources managed by the `InnoDB' storage
engine are its tablespace data files and its log files. If you specify
no `InnoDB' configuration options, MySQL creates an auto-extending 10MB
data file named `ibdata1' and two 5MB log files named `ib_logfile0' and
`ib_logfile1' in the MySQL data directory. To get good performance, you
should explicitly provide `InnoDB' parameters as discussed in the
following examples. Naturally, you should edit the settings to suit your
hardware and requirements.

*Caution*:

It is not a good idea to configure `InnoDB' to use data files or log
files on NFS volumes. Otherwise, the files might be locked by other
processes and become unavailable for use by MySQL.

The examples shown here are representative. See *Note
innodb-parameters:: for additional information about `InnoDB'-related
configuration parameters.

To set up the `InnoDB' tablespace files, use the
`innodb_data_file_path' option in the `[mysqld]' section of the
`my.cnf' option file. On Windows, you can use `my.ini' instead. The
value of `innodb_data_file_path' should be a list of one or more data
file specifications. If you name more than one data file, separate them
by semicolon (``;'') characters:

     innodb_data_file_path=DATAFILE_SPEC1[;DATAFILE_SPEC2]...

For example, the following setting explicitly creates a tablespace
having the same characteristics as the default:

     [mysqld]
     innodb_data_file_path=ibdata1:10M:autoextend

This setting configures a single 10MB data file named `ibdata1' that is
auto-extending. No location for the file is given, so by default,
`InnoDB' creates it in the MySQL data directory.

Sizes are specified using `K', `M', or `G' suffix letters to indicate
units of KB, MB, or GB.

A tablespace containing a fixed-size 50MB data file named `ibdata1' and
a 50MB auto-extending file named `ibdata2' in the data directory can be
configured like this:

     [mysqld]
     innodb_data_file_path=ibdata1:50M;ibdata2:50M:autoextend

The full syntax for a data file specification includes the file name,
its size, and several optional attributes:

     FILE_NAME:FILE_SIZE[:autoextend[:max:MAX_FILE_SIZE]]

The `autoextend' and `max' attributes can be used only for the last
data file in the `innodb_data_file_path' line.

If you specify the `autoextend' option for the last data file, `InnoDB'
extends the data file if it runs out of free space in the tablespace.
The increment is 8MB at a time by default. To modify the increment,
change the `innodb_autoextend_increment' system variable.

If the disk becomes full, you might want to add another data file on
another disk. For tablespace reconfiguration instructions, see *Note
innodb-data-log-reconfiguration::.

`InnoDB' is not aware of the file system maximum file size, so be
cautious on file systems where the maximum file size is a small value
such as 2GB. To specify a maximum size for an auto-extending data file,
use the `max' attribute following the `autoextend' attribute.  The
following configuration permits `ibdata1' to grow up to a limit of
500MB:

     [mysqld]
     innodb_data_file_path=ibdata1:10M:autoextend:max:500M

`InnoDB' creates tablespace files in the MySQL data directory by
default. To specify a location explicitly, use the
`innodb_data_home_dir' option.  For example, to use two files named
`ibdata1' and `ibdata2' but create them in the `/ibdata' directory,
configure `InnoDB' like this:

     [mysqld]
     innodb_data_home_dir = /ibdata
     innodb_data_file_path=ibdata1:50M;ibdata2:50M:autoextend

*Note*:

`InnoDB' does not create directories, so make sure that the `/ibdata'
directory exists before you start the server. This is also true of any
log file directories that you configure. Use the Unix or DOS `mkdir'
command to create any necessary directories.

Make sure that the MySQL server has the proper access rights to create
files in the data directory. More generally, the server must have
access rights in any directory where it needs to create data files or
log files.

`InnoDB' forms the directory path for each data file by textually
concatenating the value of `innodb_data_home_dir' to the data file
name, adding a path name separator (slash or backslash) between values
if necessary. If the `innodb_data_home_dir' option is not mentioned in
`my.cnf' at all, the default value is the `dot' directory `./', which
means the MySQL data directory. (The MySQL server changes its current
working directory to its data directory when it begins executing.)

If you specify `innodb_data_home_dir' as an empty string, you can
specify absolute paths for the data files listed in the
`innodb_data_file_path' value. The following example is equivalent to
the preceding one:

     [mysqld]
     innodb_data_home_dir =
     innodb_data_file_path=/ibdata/ibdata1:50M;/ibdata/ibdata2:50M:autoextend

*A simple `my.cnf' example.* Suppose that you have a computer with 512MB
RAM and one hard disk. The following example shows possible
configuration parameters in `my.cnf' or `my.ini' for `InnoDB',
including the `autoextend' attribute. The example suits most users,
both on Unix and Windows, who do not want to distribute `InnoDB' data
files and log files onto several disks. It creates an auto-extending
data file `ibdata1' and two `InnoDB' log files `ib_logfile0' and
`ib_logfile1' in the MySQL data directory.

     [mysqld]
     # You can write your other MySQL server options here
     # ...
     # Data files must be able to hold your data and indexes.
     # Make sure that you have enough free disk space.
     innodb_data_file_path = ibdata1:10M:autoextend
     #
     # Set buffer pool size to 50-80% of your computer's memory
     innodb_buffer_pool_size=256M
     innodb_additional_mem_pool_size=20M
     #
     # Set the log file size to about 25% of the buffer pool size
     innodb_log_file_size=64M
     innodb_log_buffer_size=8M
     #
     innodb_flush_log_at_trx_commit=1

Note that data files must be less than 2GB in some file systems.  The
combined size of the log files must be less than 4GB. The combined size
of data files must be at least 10MB.

When you create an `InnoDB' tablespace for the first time, it is best
that you start the MySQL server from the command prompt. `InnoDB' then
prints the information about the database creation to the screen, so
you can see what is happening. For example, on Windows, if *Note
`mysqld': mysqld. is located in `C:\Program Files\MySQL\MySQL Server
5.0\bin', you can start it like this:

     C:\> "C:\Program Files\MySQL\MySQL Server 5.0\bin\mysqld" --console

If you do not send server output to the screen, check the server's
error log to see what `InnoDB' prints during the startup process.

For an example of what the information displayed by `InnoDB' should
look like, see *Note innodb-init::.

You can place `InnoDB' options in the `[mysqld]' group of any option
file that your server reads when it starts. The locations for option
files are described in *Note option-files::.

If you installed MySQL on Windows using the installation and
configuration wizards, the option file will be the `my.ini' file
located in your MySQL installation directory. See *Note
mysql-config-wizard-starting::.

If your PC uses a boot loader where the `C:' drive is not the boot
drive, your only option is to use the `my.ini' file in your Windows
directory (typically `C:\WINDOWS'). You can use the `SET' command at
the command prompt in a console window to print the value of `WINDIR':

     C:\> SET WINDIR
     windir=C:\WINDOWS

To make sure that *Note `mysqld': mysqld. reads options only from a
specific file, use the `--defaults-file' option as the first option on
the command line when starting the server:

     mysqld --defaults-file=YOUR_PATH_TO_MY_CNF

*An advanced `my.cnf' example.* Suppose that you have a Linux computer
with 2GB RAM and three 60GB hard disks at directory paths `/', `/dr2'
and `/dr3'. The following example shows possible configuration
parameters in `my.cnf' for `InnoDB'.

     [mysqld]
     # You can write your other MySQL server options here
     # ...
     innodb_data_home_dir =
     #
     # Data files must be able to hold your data and indexes
     innodb_data_file_path = /ibdata/ibdata1:2000M;/dr2/ibdata/ibdata2:2000M:autoextend
     #
     # Set buffer pool size to 50-80% of your computer's memory,
     # but make sure on Linux x86 total memory usage is < 2GB
     innodb_buffer_pool_size=1G
     innodb_additional_mem_pool_size=20M
     innodb_log_group_home_dir = /dr3/iblogs
     #
     # Set the log file size to about 25% of the buffer pool size
     innodb_log_file_size=250M
     innodb_log_buffer_size=8M
     #
     innodb_flush_log_at_trx_commit=1
     innodb_lock_wait_timeout=50
     #
     # Uncomment the next line if you want to use it
     #innodb_thread_concurrency=5

In some cases, database performance improves if the data is not all
placed on the same physical disk. Putting log files on a different disk
from data is very often beneficial for performance.  The example
illustrates how to do this. It places the two data files on different
disks and places the log files on the third disk. `InnoDB' fills the
tablespace beginning with the first data file. You can also use raw
disk partitions (raw devices) as `InnoDB' data files, which may speed
up I/O. See *Note innodb-raw-devices::.

*Warning*:

On 32-bit GNU/Linux x86, you must be careful not to set memory usage
too high. `glibc' may permit the process heap to grow over thread
stacks, which crashes your server. It is a risk if the value of the
following expression is close to or exceeds 2GB:

     innodb_buffer_pool_size
     + key_buffer_size
     + max_connections*(sort_buffer_size+read_buffer_size+binlog_cache_size)
     + max_connections*2MB

Each thread uses a stack (often 2MB, but only 256KB in MySQL binaries
provided by Oracle Corporation.) and in the worst case also uses
`sort_buffer_size + read_buffer_size' additional memory.

By compiling MySQL yourself, you can use up to 64GB of physical memory
in 32-bit Windows. See the description for
`innodb_buffer_pool_awe_mem_mb' in *Note innodb-parameters::.

*Tuning other *Note `mysqld': mysqld.  server parameters.* The
following values are typical and suit most users:

     [mysqld]
     skip-external-locking
     max_connections=200
     read_buffer_size=1M
     sort_buffer_size=1M
     #
     # Set key_buffer to 5 - 50% of your RAM depending on how much
     # you use MyISAM tables, but keep key_buffer_size + InnoDB
     # buffer pool size < 80% of your RAM
     key_buffer_size=VALUE

On Linux, if the kernel is enabled for large page support, `InnoDB' can
use large pages to allocate memory for its buffer pool and additional
memory pool. See *Note large-page-support::.


File: manual.info,  Node: innodb-multiple-tablespaces,  Next: innodb-raw-devices,  Prev: innodb-configuration,  Up: innodb-configuration

14.2.2.1 Using Per-Table Tablespaces
....................................

You can store each `InnoDB' table and its indexes in its own file. This
feature is called `multiple tablespaces' because in effect each table
has its own tablespace.

Using multiple tablespaces can be beneficial to users who want to move
specific tables to separate physical disks or who wish to restore
backups of single tables quickly without interrupting the use of other
`InnoDB' tables.

To enable multiple tablespaces, start the server with the
`--innodb_file_per_table' option.  For example, add a line to the
`[mysqld]' section of `my.cnf':

     [mysqld]
     innodb_file_per_table

With multiple tablespaces enabled, `InnoDB' stores each newly created
table into its own `TBL_NAME.ibd' file in the database directory where
the table belongs. This is similar to what the `MyISAM' storage engine
does, but `MyISAM' divides the table into a `TBL_NAME.MYD' data file
and an `TBL_NAME.MYI' index file. For `InnoDB', the data and the
indexes are stored together in the `.ibd' file. The `TBL_NAME.frm' file
is still created as usual.

You cannot freely move `.ibd' files between database directories as you
can with `MyISAM' table files. This is because the table definition
that is stored in the `InnoDB' shared tablespace includes the database
name, and because `InnoDB' must preserve the consistency of transaction
IDs and log sequence numbers.

If you remove the `innodb_file_per_table' line from `my.cnf' and
restart the server, `InnoDB' creates tables inside the shared
tablespace files again.

The `--innodb_file_per_table' option affects only table creation, not
access to existing tables. If you start the server with this option,
new tables are created using `.ibd' files, but you can still access
tables that exist in the shared tablespace. If you start the server
without this option, new tables are created in the shared tablespace,
but you can still access any tables that were created using multiple
tablespaces.

*Note*:

`InnoDB' always needs the shared tablespace because it puts its
internal data dictionary and undo logs there. The `.ibd' files are not
sufficient for `InnoDB' to operate.

To move an `.ibd' file and the associated table from one database to
another, use a *Note `RENAME TABLE': rename-table. statement:

     RENAME TABLE DB1.TBL_NAME TO DB2.TBL_NAME;

If you have a `clean' backup of an `.ibd' file, you can restore it to
the MySQL installation from which it originated as follows:

  1. Issue this *Note `ALTER TABLE': alter-table.  statement to delete
     the current `.ibd' file:

          ALTER TABLE TBL_NAME DISCARD TABLESPACE;

  2. Copy the backup `.ibd' file to the proper database directory.

  3. Issue this *Note `ALTER TABLE': alter-table.  statement to tell
     `InnoDB' to use the new `.ibd' file for the table:

          ALTER TABLE TBL_NAME IMPORT TABLESPACE;

In this context, a `clean' `.ibd' file backup is one for which the
following requirements are satisfied:

   * There are no uncommitted modifications by transactions in the
     `.ibd' file.

   * There are no unmerged insert buffer entries in the `.ibd' file.

   * Purge has removed all delete-marked index records from the `.ibd'
     file.

   * *Note `mysqld': mysqld. has flushed all modified pages of the
     `.ibd' file from the buffer pool to the file.

You can make a clean backup `.ibd' file using the following method:

  1. Stop all activity from the *Note `mysqld': mysqld. server and
     commit all transactions.

  2. Wait until *Note `SHOW ENGINE INNODB STATUS': show-engine. shows
     that there are no active transactions in the database, and the
     main thread status of `InnoDB' is `Waiting for server activity'.
     Then you can make a copy of the `.ibd' file.

Another method for making a clean copy of an `.ibd' file is to use the
commercial `InnoDB Hot Backup' tool:

  1. Use `InnoDB Hot Backup' to back up the `InnoDB' installation.

  2. Start a second *Note `mysqld': mysqld. server on the backup and
     let it clean up the `.ibd' files in the backup.


File: manual.info,  Node: innodb-raw-devices,  Next: innodb-init,  Prev: innodb-multiple-tablespaces,  Up: innodb-configuration

14.2.2.2 Using Raw Devices for the Shared Tablespace
....................................................

You can use raw disk partitions as data files in the shared tablespace.
By using a raw disk, you can perform nonbuffered I/O on Windows and on
some Unix systems without file system overhead. This may improve
performance, but you are advised to perform tests with and without raw
partitions to verify whether this is actually so on your system.

When you create a new data file, you must put the keyword `newraw'
immediately after the data file size in `innodb_data_file_path'. The
partition must be at least as large as the size that you specify. Note
that 1MB in `InnoDB' is 1024 x 1024 bytes, whereas 1MB in disk
specifications usually means 1,000,000 bytes.

     [mysqld]
     innodb_data_home_dir=
     innodb_data_file_path=/dev/hdd1:3Gnewraw;/dev/hdd2:2Gnewraw

The next time you start the server, `InnoDB' notices the `newraw'
keyword and initializes the new partition. However, do not create or
change any `InnoDB' tables yet. Otherwise, when you next restart the
server, `InnoDB' reinitializes the partition and your changes are lost.
(As a safety measure `InnoDB' prevents users from modifying data when
any partition with `newraw' is specified.)

After `InnoDB' has initialized the new partition, stop the server,
change `newraw' in the data file specification to `raw':

     [mysqld]
     innodb_data_home_dir=
     innodb_data_file_path=/dev/hdd1:3Graw;/dev/hdd2:2Graw

Then restart the server and `InnoDB' permits changes to be made.

On Windows, you can allocate a disk partition as a data file like this:

     [mysqld]
     innodb_data_home_dir=
     innodb_data_file_path=//./D::10Gnewraw

The `//./' corresponds to the Windows syntax of `\\.\' for accessing
physical drives.

When you use a raw disk partition, be sure that it has permissions that
enable read and write access by the account used for running the MySQL
server. For example, if you run the server as the `mysql' user, the
partition must permit read and write access to `mysql'. If you run the
server with the `--memlock' option, the server must be run as `root', so
the partition must permit access to `root'.


File: manual.info,  Node: innodb-init,  Next: error-creating-innodb,  Prev: innodb-raw-devices,  Up: innodb-configuration

14.2.2.3 Creating the `InnoDB' Tablespace
.........................................

Suppose that you have installed MySQL and have edited your option file
so that it contains the necessary `InnoDB' configuration parameters.
Before starting MySQL, you should verify that the directories you have
specified for `InnoDB' data files and log files exist and that the
MySQL server has access rights to those directories. `InnoDB' does not
create directories, only files. Check also that you have enough disk
space for the data and log files.

It is best to run the MySQL server *Note `mysqld': mysqld.  from the
command prompt when you first start the server with `InnoDB' enabled,
not from *Note `mysqld_safe': mysqld-safe. or as a Windows service.
When you run from a command prompt you see what *Note `mysqld': mysqld.
prints and what is happening. On Unix, just invoke *Note `mysqld':
mysqld. On Windows, start *Note `mysqld': mysqld. with the `--console'
option to direct the output to the console window.

When you start the MySQL server after initially configuring `InnoDB' in
your option file, `InnoDB' creates your data files and log files, and
prints something like this:

     InnoDB: The first specified datafile /home/heikki/data/ibdata1
     did not exist:
     InnoDB: a new database to be created!
     InnoDB: Setting file /home/heikki/data/ibdata1 size to 134217728
     InnoDB: Database physically writes the file full: wait...
     InnoDB: datafile /home/heikki/data/ibdata2 did not exist:
     new to be created
     InnoDB: Setting file /home/heikki/data/ibdata2 size to 262144000
     InnoDB: Database physically writes the file full: wait...
     InnoDB: Log file /home/heikki/data/logs/ib_logfile0 did not exist:
     new to be created
     InnoDB: Setting log file /home/heikki/data/logs/ib_logfile0 size
     to 5242880
     InnoDB: Log file /home/heikki/data/logs/ib_logfile1 did not exist:
     new to be created
     InnoDB: Setting log file /home/heikki/data/logs/ib_logfile1 size
     to 5242880
     InnoDB: Doublewrite buffer not found: creating new
     InnoDB: Doublewrite buffer created
     InnoDB: Creating foreign key constraint system tables
     InnoDB: Foreign key constraint system tables created
     InnoDB: Started
     mysqld: ready for connections

At this point `InnoDB' has initialized its tablespace and log files.
You can connect to the MySQL server with the usual MySQL client
programs like *Note `mysql': mysql. When you shut down the MySQL server
with *Note `mysqladmin shutdown': mysqladmin, the output is like this:

     010321 18:33:34  mysqld: Normal shutdown
     010321 18:33:34  mysqld: Shutdown Complete
     InnoDB: Starting shutdown...
     InnoDB: Shutdown completed

You can look at the data file and log directories and you see the files
created there. When MySQL is started again, the data files and log
files have been created already, so the output is much briefer:

     InnoDB: Started
     mysqld: ready for connections

If you add the `innodb_file_per_table' option to `my.cnf', `InnoDB'
stores each table in its own `.ibd' file in the same MySQL database
directory where the `.frm' file is created. See *Note
innodb-multiple-tablespaces::.


File: manual.info,  Node: error-creating-innodb,  Prev: innodb-init,  Up: innodb-configuration

14.2.2.4 Dealing with `InnoDB' Initialization Problems
......................................................

If `InnoDB' prints an operating system error during a file operation,
usually the problem has one of the following causes:

   * You did not create the `InnoDB' data file directory or the
     `InnoDB' log directory.

   * *Note `mysqld': mysqld. does not have access rights to create
     files in those directories.

   * *Note `mysqld': mysqld. cannot read the proper `my.cnf' or `my.ini'
     option file, and consequently does not see the options that you
     specified.

   * The disk is full or a disk quota is exceeded.

   * You have created a subdirectory whose name is equal to a data file
     that you specified, so the name cannot be used as a file name.

   * There is a syntax error in the `innodb_data_home_dir' or
     `innodb_data_file_path' value.

If something goes wrong when `InnoDB' attempts to initialize its
tablespace or its log files, you should delete all files created by
`InnoDB'. This means all `ibdata' files and all `ib_logfile' files. In
case you have already created some `InnoDB' tables, delete the
corresponding `.frm' files for these tables (and any `.ibd' files if
you are using multiple tablespaces) from the MySQL database directories
as well. Then you can try the `InnoDB' database creation again. It is
best to start the MySQL server from a command prompt so that you see
what is happening.


File: manual.info,  Node: innodb-parameters,  Next: using-innodb-tables,  Prev: innodb-configuration,  Up: innodb-storage-engine

14.2.3 `InnoDB' Startup Options and System Variables
----------------------------------------------------

This section describes the `InnoDB'-related command options and system
variables. System variables that are true or false can be enabled at
server startup by naming them, or disabled by using a `--skip' prefix.
For example, to enable or disable `InnoDB' checksums, you can use
`--innodb_checksums' or `--skip-innodb_checksums' on the command line,
or `innodb_checksums' or `skip-innodb_checksums' in an option file.
System variables that take a numeric value can be specified as
`--VAR_NAME=VALUE' on the command line or as `VAR_NAME=VALUE' in option
files. For more information on specifying options and system variables,
see *Note program-options::. Many of the system variables can be
changed at runtime (see *Note dynamic-system-variables::).

*InnoDB Option/Variable Reference*

Name           Cmd-Line    Option file System Var  Status Var  Var Scope   Dynamic
Com_show_innodb_status                                    Yes         Both        No
Com_show_ndb_status                                    Yes         Both        No
foreign_key_checks                        Yes                     Session     Yes
have_innodb                            Yes                     Global      No
innodb         Yes         Yes                                             
innodb_adaptive_hash_indexYes         Yes         Yes                     Global      No
innodb_additional_mem_pool_sizeYes         Yes         Yes                     Global      No
innodb_autoextend_incrementYes         Yes         Yes                     Global      Yes
innodb_buffer_pool_awe_mem_mbYes         Yes         Yes                     Global      No
Innodb_buffer_pool_pages_data                                    Yes         Global      No
Innodb_buffer_pool_pages_dirty                                    Yes         Global      No
Innodb_buffer_pool_pages_flushed                                    Yes         Global      No
Innodb_buffer_pool_pages_free                                    Yes         Global      No
Innodb_buffer_pool_pages_latched                                    Yes         Global      No
Innodb_buffer_pool_pages_misc                                    Yes         Global      No
Innodb_buffer_pool_pages_total                                    Yes         Global      No
Innodb_buffer_pool_read_ahead_rnd                                    Yes         Global      No
Innodb_buffer_pool_read_ahead_seq                                    Yes         Global      No
Innodb_buffer_pool_read_requests                                    Yes         Global      No
Innodb_buffer_pool_reads                                    Yes         Global      No
innodb_buffer_pool_sizeYes         Yes         Yes                     Global      No
Innodb_buffer_pool_wait_free                                    Yes         Global      No
Innodb_buffer_pool_write_requests                                    Yes         Global      No
innodb_checksumsYes         Yes         Yes                     Global      No
innodb_commit_concurrencyYes         Yes         Yes                     Global      Yes
innodb_concurrency_ticketsYes         Yes         Yes                     Global      Yes
innodb_data_file_pathYes         Yes         Yes                     Global      No
Innodb_data_fsyncs                                    Yes         Global      No
innodb_data_home_dirYes         Yes         Yes                     Global      No
Innodb_data_pending_fsyncs                                    Yes         Global      No
Innodb_data_pending_reads                                    Yes         Global      No
Innodb_data_pending_writes                                    Yes         Global      No
Innodb_data_read                                    Yes         Global      No
Innodb_data_reads                                    Yes         Global      No
Innodb_data_writes                                    Yes         Global      No
Innodb_data_written                                    Yes         Global      No
Innodb_dblwr_pages_written                                    Yes         Global      No
Innodb_dblwr_writes                                    Yes         Global      No
innodb_doublewriteYes         Yes         Yes                     Global      No
innodb_fast_shutdownYes         Yes         Yes                     Global      Yes
innodb_file_io_threadsYes         Yes         Yes                     Global      No
innodb_file_per_tableYes         Yes         Yes                     Global      No
innodb_flush_log_at_trx_commitYes         Yes         Yes                     Global      Yes
innodb_flush_methodYes         Yes         Yes                     Global      No
innodb_force_recoveryYes         Yes         Yes                     Global      No
innodb_lock_wait_timeoutYes         Yes         Yes                     Global      No
innodb_locks_unsafe_for_binlogYes         Yes         Yes                     Global      No
innodb_log_arch_dirYes         Yes         Yes                     Global      No
innodb_log_archiveYes         Yes         Yes                     Global      No
innodb_log_buffer_sizeYes         Yes         Yes                     Global      No
innodb_log_file_sizeYes         Yes         Yes                     Global      No
innodb_log_files_in_groupYes         Yes         Yes                     Global      No
innodb_log_group_home_dirYes         Yes         Yes                     Global      No
Innodb_log_waits                                    Yes         Global      No
Innodb_log_write_requests                                    Yes         Global      No
Innodb_log_writes                                    Yes         Global      No
innodb_max_dirty_pages_pctYes         Yes         Yes                     Global      Yes
innodb_max_purge_lagYes         Yes         Yes                     Global      Yes
innodb_mirrored_log_groupsYes         Yes         Yes                     Global      No
innodb_open_filesYes         Yes         Yes                     Global      No
Innodb_os_log_fsyncs                                    Yes         Global      No
Innodb_os_log_pending_fsyncs                                    Yes         Global      No
Innodb_os_log_pending_writes                                    Yes         Global      No
Innodb_os_log_written                                    Yes         Global      No
Innodb_page_size                                    Yes         Global      No
Innodb_pages_created                                    Yes         Global      No
Innodb_pages_read                                    Yes         Global      No
Innodb_pages_written                                    Yes         Global      No
innodb_rollback_on_timeoutYes         Yes         Yes                     Global      No
Innodb_row_lock_current_waits                                    Yes         Global      No
Innodb_row_lock_time                                    Yes         Global      No
Innodb_row_lock_time_avg                                    Yes         Global      No
Innodb_row_lock_time_max                                    Yes         Global      No
Innodb_row_lock_waits                                    Yes         Global      No
Innodb_rows_deleted                                    Yes         Global      No
Innodb_rows_inserted                                    Yes         Global      No
Innodb_rows_read                                    Yes         Global      No
Innodb_rows_updated                                    Yes         Global      No
innodb-safe-binlogYes         Yes                                             
innodb-status-fileYes         Yes         Yes                     Global      No
innodb_support_xaYes         Yes         Yes                     Both        Yes
innodb_sync_spin_loopsYes         Yes         Yes                     Global      Yes
innodb_table_locksYes         Yes         Yes                     Both        Yes
innodb_thread_concurrencyYes         Yes         Yes                     Global      Yes
innodb_thread_sleep_delayYes         Yes         Yes                     Global      Yes
innodb_use_legacy_cardinality_algorithmYes         Yes         Yes                     Global      Yes
timed_mutexes  Yes         Yes         Yes                     Global      Yes
unique_checks                          Yes                     Session     Yes

* `InnoDB' Command Options *

   *  `--innodb'

     Enables the `InnoDB' storage engine, if the server was compiled
     with `InnoDB' support.

     To disable `InnoDB', use `--skip-innodb'.  In this case, the
     server will not start if the default storage engine is set to
     *Note `InnoDB': innodb-storage-engine. Use
     `--default-storage-engine' to set the default to some other engine
     if necessary.

   *  `--innodb-status-file'

     Controls whether `InnoDB' creates a file named
     `innodb_status.<PID>' in the MySQL data directory. If enabled,
     `InnoDB' periodically writes the output of *Note `SHOW ENGINE
     INNODB STATUS': show-engine. to this file.

     By default, the file is not created. To create it, start *Note
     `mysqld': mysqld. with the `--innodb-status-file=1' option.  The
     file is deleted during normal shutdown.

   * `--skip-innodb'

     Disable the `InnoDB' storage engine. See the description of
     `--innodb'.

* `InnoDB' System Variables *

   *  `innodb_adaptive_hash_index'

     Options for innodb_adaptive_hash_index      *Version Introduced* 5.0.52          
     *Command-Line        `--innodb_adaptive_hash_index=#'        
     Format*                              
     *Option-File Format* `innodb_adaptive_hash_index'        
     *Option Sets         Yes,            
     Variable*            `innodb_adaptive_hash_index'        
     *Variable Name*      `innodb_adaptive_hash_index'        
     *Variable Scope*     Global          
     *Dynamic Variable*   No              
                          *Permitted        
                          Values          
                          *               
     *Type*               `boolean'        
     *Default*            `ON'            


     Whether InnoDB adaptive hash indexes are enabled or disabled (see
     *Note innodb-adaptive-hash::). This variable is enabled by
     default. Use `--skip-innodb_adaptive_hash_index' at server startup
     to disable it. This variable was added in MySQL 5.0.52.

   *  `innodb_additional_mem_pool_size'

     Options for innodb_additional_mem_pool_size      *Command-Line        `--innodb_additional_mem_pool_size=#'        
     Format*                              
     *Option-File Format* `innodb_additional_mem_pool_size'        
     *Option Sets         Yes,            
     Variable*            `innodb_additional_mem_pool_size'        
     *Variable Name*      `innodb_additional_mem_pool_size'        
     *Variable Scope*     Global          
     *Dynamic Variable*   No              
     *Deprecated*         5.6.3           
                          *Permitted        
                          Values          
                          *               
     *Type*               `numeric'        
     *Default*            `1048576'        
     *Range*              `524288         
                          ..              
                          4294967295'        


     The size in bytes of a memory pool `InnoDB' uses to store data
     dictionary information and other internal data structures. The
     more tables you have in your application, the more memory you need
     to allocate here. If `InnoDB' runs out of memory in this pool, it
     starts to allocate memory from the operating system and writes
     warning messages to the MySQL error log. The default value is 1MB.

   *  `innodb_autoextend_increment'

     Options for innodb_autoextend_increment      *Command-Line        `--innodb_autoextend_increment=#'        
     Format*                              
     *Option-File Format* `innodb_autoextend_increment'        
     *Option Sets         Yes,            
     Variable*            `innodb_autoextend_increment'        
     *Variable Name*      `innodb_autoextend_increment'        
     *Variable Scope*     Global          
     *Dynamic Variable*   Yes             
                          *Permitted        
                          Values          
                          *               
     *Type*               `numeric'        
     *Default*            `8'             
     *Range*              `1 ..           
                          1000'           


     The increment size (in MB) for extending the size of an
     auto-extending shared tablespace file when it becomes full.  The
     default value is 8. This variable does not affect the per-table
     tablespace files that are created if you use
     `innodb_file_per_table=1'.  Those files are auto-extending
     regardless of the value of `innodb_autoextend_increment'.  The
     initial extensions are by small amounts, after which extensions
     occur in increments of 4MB.

   *  `innodb_buffer_pool_awe_mem_mb'

     Options for innodb_buffer_pool_awe_mem_mb      *Command-Line        `--innodb_buffer_pool_awe_mem_mb=#'        
     Format*                              
     *Option-File Format* `innodb_buffer_pool_awe_mem_mb'        
     *Option Sets         Yes,            
     Variable*            `innodb_buffer_pool_awe_mem_mb'        
     *Variable Name*      `innodb_buffer_pool_awe_mem_mb'        
     *Variable Scope*     Global          
     *Dynamic Variable*   No              
     *Platform Specific*  windows         
                          *Permitted        
                          Values          
                          *               
     *Type* (windows)     `numeric'        
     *Default*            `0'             
     *Range*              `0 ..           
                          63000'          


     The size of the buffer pool (in MB), if it is placed in the AWE
     memory. If it is greater than 0, `innodb_buffer_pool_size' is the
     window in the 32-bit address space of *Note `mysqld': mysqld.
     where `InnoDB' maps that AWE memory. A good value for
     `innodb_buffer_pool_size' is 500MB. The maximum possible value is
     63000.

     To take advantage of AWE memory, you will need to recompile MySQL
     yourself. The current project settings needed for doing this can
     be found in the `innobase/os/os0proc.c' source file.

     This variable is relevant only in 32-bit Windows. If your 32-bit
     Windows operating system supports more than 4GB memory, using
     so-called `Address Windowing Extensions,' you can allocate the
     `InnoDB' buffer pool into the AWE physical memory using this
     variable.

   *  `innodb_buffer_pool_size'

     Options for innodb_buffer_pool_size      *Command-Line        `--innodb_buffer_pool_size=#'        
     Format*                              
     *Option-File Format* `innodb_buffer_pool_size'        
     *Option Sets         Yes,            
     Variable*            `innodb_buffer_pool_size'        
     *Variable Name*      `innodb_buffer_pool_size'        
     *Variable Scope*     Global          
     *Dynamic Variable*   No              


     The size in bytes of the memory buffer `InnoDB' uses to cache data
     and indexes of its tables. The default value is 8MB. The larger
     you set this value, the less disk I/O is needed to access data in
     tables.  On a dedicated database server, you may set this to up to
     80% of the machine physical memory size. However, do not set it
     too large because competition for physical memory might cause
     paging in the operating system. Also, the time to initialize the
     buffer pool is roughly proportional to its size. On large
     installations, this initialization time may be significant.  For
     example, on a modern Linux x86_64 server, initialization of a 10GB
     buffer pool takes approximately 6 seconds. See *Note
     innodb-buffer-pool::

   *  `innodb_checksums'

     Options for innodb_checksums      *Version Introduced* 5.0.3           
     *Command-Line        `--innodb_checksums'        
     Format*                              
     *Option-File Format* `innodb_checksums'        
     *Option Sets         Yes,            
     Variable*            `innodb_checksums'        
     *Variable Name*      `innodb_checksums'        
     *Variable Scope*     Global          
     *Dynamic Variable*   No              
                          *Permitted        
                          Values          
                          *               
     *Type*               `boolean'        
     *Default*            `ON'            


     `InnoDB' can use checksum validation on all pages read from the
     disk to ensure extra fault tolerance against broken hardware or
     data files. This validation is enabled by default. However, under
     some rare circumstances (such as when running benchmarks) this
     extra safety feature is unneeded and can be disabled with
     `--skip-innodb_checksums'. This variable was added in MySQL 5.0.3.

   *  `innodb_commit_concurrency'

     Options for innodb_commit_concurrency      *Version Introduced* 5.0.12          
     *Command-Line        `--innodb_commit_concurrency=#'        
     Format*                              
     *Option-File Format* `innodb_commit_concurrency'        
     *Option Sets         Yes,            
     Variable*            `innodb_commit_concurrency'        
     *Variable Name*      `innodb_commit_concurrency'        
     *Variable Scope*     Global          
     *Dynamic Variable*   Yes             
                          *Permitted        
                          Values          
                          *               
     *Type*               `numeric'        
     *Default*            `0'             
     *Range*              `0 ..           
                          1000'           


     The number of threads that can commit at the same time. A value of
     0 (the default) permits any number of transactions to commit
     simultaneously. This variable was added in MySQL 5.0.12.

   *  `innodb_concurrency_tickets'

     Options for innodb_concurrency_tickets      *Version Introduced* 5.0.3           
     *Command-Line        `--innodb_concurrency_tickets=#'        
     Format*                              
     *Option-File Format* `innodb_concurrency_tickets'        
     *Option Sets         Yes,            
     Variable*            `innodb_concurrency_tickets'        
     *Variable Name*      `innodb_concurrency_tickets'        
     *Variable Scope*     Global          
     *Dynamic Variable*   Yes             
                          *Permitted        
                          Values          
                          *               
     *Type*               `numeric'        
     *Default*            `500'           
     *Range*              `1 ..           
                          4294967295'        


     The number of threads that can enter `InnoDB' concurrently is
     determined by the `innodb_thread_concurrency' variable. A thread
     is placed in a queue when it tries to enter `InnoDB' if the number
     of threads has already reached the concurrency limit. When a
     thread is permitted to enter `InnoDB', it is given a number of
     `free tickets' equal to the value of `innodb_concurrency_tickets',
     and the thread can enter and leave `InnoDB' freely until it has
     used up its tickets. After that point, the thread again becomes
     subject to the concurrency check (and possible queuing) the next
     time it tries to enter `InnoDB'. The default value is 500. This
     variable was added in MySQL 5.0.3.

   *  `innodb_data_file_path'

     Options for innodb_data_file_path      *Command-Line        `--innodb_data_file_path=name'        
     Format*                              
     *Option-File Format* `innodb_data_file_path'        
     *Variable Name*      `innodb_data_file_path'        
     *Variable Scope*     Global          
     *Dynamic Variable*   No              
                          *Permitted        
                          Values          
                          *               
     *Type*               `file           
                          name'           


     The paths to individual data files and their sizes. The full
     directory path to each data file is formed by concatenating
     `innodb_data_home_dir' to each path specified here. The file sizes
     are specified in KB, MB, or GB (1024MB) by appending `K', `M', or
     `G' to the size value. The sum of the sizes of the files must be
     at least 10MB. If you do not specify `innodb_data_file_path', the
     default behavior is to create a single 10MB auto-extending data
     file named `ibdata1'. The size limit of individual files is
     determined by your operating system.  You can set the file size to
     more than 4GB on those operating systems that support big files.
     You can also use raw disk partitions as data files. For detailed
     information on configuring `InnoDB' tablespace files, see *Note
     innodb-configuration::.

   *  `innodb_data_home_dir'

     Options for innodb_data_home_dir      *Command-Line        `--innodb_data_home_dir=path'        
     Format*                              
     *Option-File Format* `innodb_data_home_dir'        
     *Option Sets         Yes,            
     Variable*            `innodb_data_home_dir'        
     *Variable Name*      `innodb_data_home_dir'        
     *Variable Scope*     Global          
     *Dynamic Variable*   No              
                          *Permitted        
                          Values          
                          *               
     *Type*               `file           
                          name'           


     The common part of the directory path for all `InnoDB' data files
     in the shared tablespace.  This setting does not affect the
     location of per-file tablespaces when `innodb_file_per_table' is
     enabled. The default value is the MySQL data directory. If you
     specify the value as an empty string, you can use absolute file
     paths in `innodb_data_file_path'.

   *  `innodb_doublewrite'

     Options for innodb_doublewrite      *Version Introduced* 5.0.3           
     *Command-Line        `--innodb-doublewrite'        
     Format*                              
     *Option-File Format* `innodb_doublewrite'        
     *Option Sets         Yes,            
     Variable*            `innodb_doublewrite'        
     *Variable Name*      `innodb_doublewrite'        
     *Variable Scope*     Global          
     *Dynamic Variable*   No              
                          *Permitted        
                          Values          
                          *               
     *Type*               `boolean'        


     If this variable is enabled (the default), `InnoDB' stores all
     data twice, first to the doublewrite buffer, and then to the
     actual data files. This variable can be turned off with
     `--skip-innodb_doublewrite' for benchmarks or cases when top
     performance is needed rather than concern for data integrity or
     possible failures. This variable was added in MySQL 5.0.3.

   *  `innodb_fast_shutdown'

     Options for innodb_fast_shutdown      *Command-Line        `--innodb_fast_shutdown[=#]'        
     Format*                              
     *Option-File Format* `innodb_fast_shutdown'        
     *Option Sets         Yes,            
     Variable*            `innodb_fast_shutdown'        
     *Variable Name*      `innodb_fast_shutdown'        
     *Variable Scope*     Global          
     *Dynamic Variable*   Yes             
                          *Permitted        
                          Values          
                          *               
     *Type*               `numeric'        
     *Default*            `1'             
     *Valid Values*       `0' `1'         
                          `2'             


     The `InnoDB' shutdown mode. By default, the value is 1, which
     causes a `fast' shutdown (the normal type of shutdown). If the
     value is 0, `InnoDB' does a full purge and an insert buffer merge
     before a shutdown. These operations can take minutes, or even
     hours in extreme cases. If the value is 1, `InnoDB' skips these
     operations at shutdown.  If the value is 2, `InnoDB' will just
     flush its logs and then shut down cold, as if MySQL had crashed; no
     committed transaction will be lost, but crash recovery will be
     done at the next startup. The value of 2 can be used as of MySQL
     5.0.5, except that it cannot be used on NetWare.

   *  `innodb_file_io_threads'

     Options for innodb_file_io_threads      *Command-Line        `--innodb_file_io_threads=#'        
     Format*                              
     *Option-File Format* `innodb_file_io_threads'        
     *Option Sets         Yes,            
     Variable*            `innodb_file_io_threads'        
     *Variable Name*      `innodb_file_io_threads'        
     *Variable Scope*     Global          
     *Dynamic Variable*   No              
                          *Permitted        
                          Values          
                          *               
     *Type*               `numeric'        
     *Default*            `4'             
     *Range*              `4 ..           
                          64'             


     The number of file I/O threads in `InnoDB'.  Normally, this should
     be left at the default value of 4, but disk I/O on Windows may
     benefit from a larger number. On Unix, increasing the number has
     no effect; `InnoDB' always uses the default value.

   *  `innodb_file_per_table'

     Options for innodb_file_per_table      *Command-Line        `--innodb_file_per_table'        
     Format*                              
     *Option-File Format* `innodb_file_per_table'        
     *Variable Name*      `innodb_file_per_table'        
     *Variable Scope*     Global          
     *Dynamic Variable*   No              
                          *Permitted        
                          Values          
                          *               
     *Type*               `boolean'        
     *Default*            `OFF'           


     If `innodb_file_per_table' is disabled (the default), `InnoDB'
     creates tables in the shared tablespace. If
     `innodb_file_per_table' is enabled, `InnoDB' creates each new table
     using its own `.ibd' file for storing data and indexes, rather
     than in the shared tablespace. See *Note
     innodb-multiple-tablespaces::.

   *  `innodb_flush_log_at_trx_commit'

     Options for innodb_flush_log_at_trx_commit      *Command-Line        `--innodb_flush_log_at_trx_commit[=#]'        
     Format*                              
     *Option-File Format* `innodb_flush_log_at_trx_commit'        
     *Option Sets         Yes,            
     Variable*            `innodb_flush_log_at_trx_commit'        
     *Variable Name*      `innodb_flush_log_at_trx_commit'        
     *Variable Scope*     Global          
     *Dynamic Variable*   Yes             
                          *Permitted        
                          Values          
                          *               
     *Type*               `enumeration'        
     *Default*            `1'             
     *Valid Values*       `0' `1'         
                          `2'             


     If the value of `innodb_flush_log_at_trx_commit' is 0, the log
     buffer is written out to the log file once per second and the
     flush to disk operation is performed on the log file, but nothing
     is done at a transaction commit. When the value is 1 (the
     default), the log buffer is written out to the log file at each
     transaction commit and the flush to disk operation is performed on
     the log file. When the value is 2, the log buffer is written out
     to the file at each commit, but the flush to disk operation is not
     performed on it. However, the flushing on the log file takes place
     once per second also when the value is 2. Note that the
     once-per-second flushing is not 100% guaranteed to happen every
     second, due to process scheduling issues.

     The default value of 1 is the value required for ACID compliance.
     You can achieve better performance by setting the value different
     from 1, but then you can lose at most one second worth of
     transactions in a crash. With a value of 0, any *Note `mysqld':
     mysqld. process crash can erase the last second of transactions.
     With a value of 2, then only an operating system crash or a power
     outage can erase the last second of transactions. However,
     `InnoDB''s crash recovery is not affected and thus crash recovery
     does work regardless of the value.

     For the greatest possible durability and consistency in a
     replication setup using `InnoDB' with transactions, you should use
     `innodb_flush_log_at_trx_commit=1', `sync_binlog=1', and, before
     MySQL 5.0.3, `innodb-safe-binlog' in your master server `my.cnf'
     file.  (`innodb-safe-binlog' is not needed from 5.0.3 on.)

     *Caution*:

     Many operating systems and some disk hardware fool the
     flush-to-disk operation. They may tell *Note `mysqld': mysqld.
     that the flush has taken place, even though it has not. Then the
     durability of transactions is not guaranteed even with the setting
     1, and in the worst case a power outage can even corrupt the
     `InnoDB' database. Using a battery-backed disk cache in the SCSI
     disk controller or in the disk itself speeds up file flushes, and
     makes the operation safer. You can also try using the Unix command
     `hdparm' to disable the caching of disk writes in hardware caches,
     or use some other command specific to the hardware vendor.

   *  `innodb_flush_method'

     Options for innodb_flush_method      *Command-Line        `--innodb_flush_method=name'        
     Format*                              
     *Option-File Format* `innodb_flush_method'        
     *Option Sets         Yes,            
     Variable*            `innodb_flush_method'        
     *Variable Name*      `innodb_flush_method'        
     *Variable Scope*     Global          
     *Dynamic Variable*   No              
                          *Permitted        
                          Values          
                          *               
     *Type* (windows)     `enumeration'        
     *Default*            `async_unbuffered'        


     If set to `fdatasync' (the default), `InnoDB' uses `fsync()' to
     flush both the data and log files. If set to `O_DSYNC', `InnoDB'
     uses `O_SYNC' to open and flush the log files, and `fsync()' to
     flush the data files. If `O_DIRECT' is specified (available on some
     GNU/Linux versions, FreeBSD, and Solaris), `InnoDB' uses
     `O_DIRECT' (or `directio()' on Solaris) to open the data files,
     and uses `fsync()' to flush both the data and log files. Note that
     `InnoDB' uses `fsync()' instead of `fdatasync()', and it does not
     use `O_DSYNC' by default because there have been problems with it
     on many varieties of Unix. This variable is relevant only for
     Unix. On Windows, the flush method is always `async_unbuffered'
     and cannot be changed.

     Different values of this variable can have a marked effect on
     `InnoDB' performance. For example, on some systems where `InnoDB'
     data and log files are located on a SAN, it has been found that
     setting `innodb_flush_method' to `O_DIRECT' can degrade
     performance of simple *Note `SELECT': select. statements by a
     factor of three.

   *  `innodb_force_recovery'

     Options for innodb_force_recovery      *Command-Line        `--innodb_force_recovery=#'        
     Format*                              
     *Option-File Format* `innodb_force_recovery'        
     *Option Sets         Yes,            
     Variable*            `innodb_force_recovery'        
     *Variable Name*      `innodb_force_recovery'        
     *Variable Scope*     Global          
     *Dynamic Variable*   No              
                          *Permitted        
                          Values          
                          *               
     *Type*               `enumeration'        
     *Default*            `0'             
     *Valid Values*       `0' `1'         
                          `2' `3'         
                          `4' `5'         
                          `6'             


     The crash recovery mode. Possible values are from 0 to 6. The
     meanings of these values are described in *Note
     forcing-innodb-recovery::.

     *Warning*:

     This variable should be set greater than 0 only in an emergency
     situation when you want to dump your tables from a corrupt
     database! As a safety measure, `InnoDB' prevents any changes to
     its data when this variable is greater than 0.

   *  `innodb_lock_wait_timeout'

     Options for innodb_lock_wait_timeout      *Command-Line        `--innodb_lock_wait_timeout=#'        
     Format*                              
     *Option-File Format* `innodb_lock_wait_timeout'        
     *Option Sets         Yes,            
     Variable*            `innodb_lock_wait_timeout'        
     *Variable Name*      `innodb_lock_wait_timeout'        
     *Variable Scope*     Global          
     *Dynamic Variable*   No              
                          *Permitted        
                          Values          
                          *               
     *Type*               `numeric'        
     *Default*            `50'            
     *Range*              `1 ..           
                          1073741824'        


     The timeout in seconds an `InnoDB' transaction may wait for a row
     lock before giving up. The default value is 50 seconds. A
     transaction that tries to access a row that is locked by another
     `InnoDB' transaction will hang for at most this many seconds
     before issuing the following error:

          ERROR 1205 (HY000): Lock wait timeout exceeded; try restarting transaction

     When a lock wait timeout occurs, the current statement is not
     executed. The current transaction is _not_ rolled back. (Until
     MySQL 5.0.13 `InnoDB' rolled back the entire transaction if a lock
     wait timeout happened. You can restore this behavior by starting
     the server with the `--innodb_rollback_on_timeout' option,
     available as of MySQL 5.0.32. See also *Note
     innodb-error-handling::.)

     `innodb_lock_wait_timeout' applies to `InnoDB' row locks only. A
     MySQL table lock does not happen inside `InnoDB' and this timeout
     does not apply to waits for table locks.

     `InnoDB' does detect transaction deadlocks in its own lock table
     immediately and rolls back one transaction.  The lock wait timeout
     value does not apply to such a wait.

   *  `innodb_locks_unsafe_for_binlog'

     Options for innodb_locks_unsafe_for_binlog      *Command-Line        `--innodb_locks_unsafe_for_binlog'        
     Format*                              
     *Option-File Format* `innodb_locks_unsafe_for_binlog'        
     *Option Sets         Yes,            
     Variable*            `innodb_locks_unsafe_for_binlog'        
     *Variable Name*      `innodb_locks_unsafe_for_binlog'        
     *Variable Scope*     Global          
     *Dynamic Variable*   No              
     *Deprecated*         5.6.3           
                          *Permitted        
                          Values          
                          *               
     *Type*               `boolean'        
     *Default*            `OFF'           


     This variable affects how `InnoDB' uses gap locking for searches
     and index scans. Normally, `InnoDB' uses an algorithm called
     _next-key locking_ that combines index-row locking with gap
     locking. `InnoDB' performs row-level locking in such a way that
     when it searches or scans a table index, it sets shared or
     exclusive locks on the index records it encounters. Thus, the
     row-level locks are actually index-record locks. In addition, a
     next-key lock on an index record also affects the `gap' before
     that index record. That is, a next-key lock is an index-record
     lock plus a gap lock on the gap preceding the index record. If one
     session has a shared or exclusive lock on record `R' in an index,
     another session cannot insert a new index record in the gap
     immediately before `R' in the index order. See *Note
     innodb-record-level-locks::.

     By default, the value of `innodb_locks_unsafe_for_binlog' is 0
     (disabled), which means that gap locking is enabled: `InnoDB' uses
     next-key locks for searches and index scans. To enable the
     variable, set it to 1. This causes gap locking to be disabled:
     `InnoDB' uses only index-record locks for searches and index scans.

     Enabling `innodb_locks_unsafe_for_binlog' does not disable the use
     of gap locking for foreign-key constraint checking or
     duplicate-key checking.

     The effect of enabling `innodb_locks_unsafe_for_binlog' is similar
     to but not identical to setting the transaction isolation level to
     `READ COMMITTED':

        * Enabling `innodb_locks_unsafe_for_binlog' is a global setting
          and affects all sessions, whereas the isolation level can be
          set globally for all sessions, or individually per session.

        * `innodb_locks_unsafe_for_binlog' can be set only at server
          startup, whereas the isolation level can be set at startup or
          changed at runtime.

     `READ COMMITTED' therefore offers finer and more flexible control
     than `innodb_locks_unsafe_for_binlog'.  For additional details
     about the effect of isolation level on gap locking, see *Note
     set-transaction::.

     Enabling `innodb_locks_unsafe_for_binlog' may cause phantom
     problems because other sessions can insert new rows into the gaps
     when gap locking is disabled. Suppose that there is an index on
     the `id' column of the `child' table and that you want to read and
     lock all rows from the table having an identifier value larger
     than 100, with the intention of updating some column in the
     selected rows later:

          SELECT * FROM child WHERE id > 100 FOR UPDATE;

     The query scans the index starting from the first record where
     `id' is greater than 100. If the locks set on the index records in
     that range do not lock out inserts made in the gaps, another
     session can insert a new row into the table. Consequently, if you
     were to execute the same *Note `SELECT': select. again within the
     same transaction, you would see a new row in the result set
     returned by the query. This also means that if new items are added
     to the database, `InnoDB' does not guarantee serializability.
     Therefore, if `innodb_locks_unsafe_for_binlog' is enabled,
     `InnoDB' guarantees at most an isolation level of `READ
     COMMITTED'. (Conflict serializability is still guaranteed.) For
     additional information about phantoms, see *Note
     innodb-next-key-locking::.

     Starting from MySQL 5.0.2, enabling
     `innodb_locks_unsafe_for_binlog' has an additional effect. For
     *Note `UPDATE': update. or *Note `DELETE': delete. statements,
     `InnoDB' holds locks only for rows that it updates or deletes.
     Record locks for nonmatching rows are released after MySQL has
     evaluated the `WHERE' condition. This greatly reduces the
     probability of deadlocks, but they can still happen. Note that
     enabling this variable still does not permit operations such as
     *Note `UPDATE': update. to overtake other similar operations (such
     as another *Note `UPDATE': update.) even when they affect
     different rows.

     Consider the following example, beginning with this table:

          CREATE TABLE t (a INT NOT NULL, b INT) ENGINE = InnoDB;
          INSERT INTO t VALUES (1,2),(2,3),(3,2),(4,3),(5,2);
          COMMIT;

     In this case, table has no indexes, so searches and index scans
     use the hidden clustered index for record locking (see *Note
     innodb-index-types::).

     Suppose that one client performs an *Note `UPDATE': update. using
     these statements:

          SET autocommit = 0;
          UPDATE t SET b = 5 WHERE b = 3;

     Suppose also that a second client performs an *Note `UPDATE':
     update. by executing these statements following those of the first
     client:

          SET autocommit = 0;
          UPDATE t SET b = 4 WHERE b = 2;

     As *Note `InnoDB': innodb-storage-engine. executes each *Note
     `UPDATE': update, it first acquires an exclusive lock for each
     row, and then determines whether to modify it. If *Note `InnoDB':
     innodb-storage-engine. does not modify the row and
     `innodb_locks_unsafe_for_binlog' is enabled, it releases the lock.
     Otherwise, *Note `InnoDB': innodb-storage-engine. retains the lock
     until the end of the transaction. This affects transaction
     processing as follows.

     If `innodb_locks_unsafe_for_binlog' is disabled, the first *Note
     `UPDATE': update.  acquires x-locks and does not release any of
     them:

          x-lock(1,2); retain x-lock
          x-lock(2,3); update(2,3) to (2,5); retain x-lock
          x-lock(3,2); retain x-lock
          x-lock(4,3); update(4,3) to (4,5); retain x-lock
          x-lock(5,2); retain x-lock

     The second *Note `UPDATE': update. blocks as soon as it tries to
     acquire any locks (because first update has retained locks on all
     rows), and does not proceed until the first *Note `UPDATE':
     update. commits or rolls back:

          x-lock(1,2); block and wait for first UPDATE to commit or roll back

     If `innodb_locks_unsafe_for_binlog' is enabled, the first *Note
     `UPDATE': update.  acquires x-locks and releases those for rows
     that it does not modify:

          x-lock(1,2); unlock(1,2)
          x-lock(2,3); update(2,3) to (2,5); retain x-lock
          x-lock(3,2); unlock(3,2)
          x-lock(4,3); update(4,3) to (4,5); retain x-lock
          x-lock(5,2); unlock(5,2)

     The second *Note `UPDATE': update. proceeds part way before it
     blocks. It begins acquiring x-locks, and blocks when it tries to
     acquire one for a row still locked by first *Note `UPDATE':
     update. The second *Note `UPDATE': update. does not proceed until
     the first *Note `UPDATE': update. commits or rolls back:

          x-lock(1,2); update(1,2) to (1,4); retain x-lock
          x-lock(2,3); block and wait for first UPDATE to commit or roll back

     In this case, the second *Note `UPDATE': update.  must wait for a
     commit or rollback of the first *Note `UPDATE': update, even
     though it affects different rows. The first *Note `UPDATE':
     update. has an exclusive lock on row (2,3) that it has not
     released. As the second *Note `UPDATE': update. scans rows, it
     tries to acquire an exclusive lock for that same row, which it
     cannot have.

   *  `innodb_log_arch_dir'

     This variable is unused, and is deprecated as of MySQL 5.0.24.  It
     is removed in MySQL 5.1

   *  `innodb_log_archive'

     Whether to log `InnoDB' archive files. This variable is present
     for historical reasons, but is unused.  Recovery from a backup is
     done by MySQL using its own log files, so there is no need to
     archive `InnoDB' log files. The default for this variable is 0.

   *  `innodb_log_buffer_size'

     Options for innodb_log_buffer_size      *Command-Line        `--innodb_log_buffer_size=#'        
     Format*                              
     *Option-File Format* `innodb_log_buffer_size'        
     *Option Sets         Yes,            
     Variable*            `innodb_log_buffer_size'        
     *Variable Name*      `innodb_log_buffer_size'        
     *Variable Scope*     Global          
     *Dynamic Variable*   No              
                          *Permitted        
                          Values          
                          *               
     *Type*               `numeric'        
     *Default*            `1048576'        
     *Range*              `1048576        
                          ..              
                          4294967295'        


     The size in bytes of the buffer that `InnoDB' uses to write to the
     log files on disk. The default value is 1MB. Sensible values range
     from 1MB to 8MB. A large log buffer enables large transactions to
     run without a need to write the log to disk before the
     transactions commit. Thus, if you have big transactions, making
     the log buffer larger saves disk I/O.

   *  `innodb_log_file_size'

     Options for innodb_log_file_size      *Command-Line        `--innodb_log_file_size=#'        
     Format*                              
     *Option-File Format* `innodb_log_file_size'        
     *Option Sets         Yes,            
     Variable*            `innodb_log_file_size'        
     *Variable Name*      `innodb_log_file_size'        
     *Variable Scope*     Global          
     *Dynamic Variable*   No              
                          *Permitted        
                          Values          
                          *               
     *Type*               `numeric'        
     *Default*            `5242880'        
     *Range*              `1048576        
                          ..              
                          4294967295'        


     The size in bytes of each log file in a log group. The combined
     size of log files must be less than 4GB. The default value is 5MB.
     Sensible values range from 1MB to 1/N-th of the size of the buffer
     pool, where N is the number of log files in the group. The larger
     the value, the less checkpoint flush activity is needed in the
     buffer pool, saving disk I/O.  But larger log files also mean that
     recovery is slower in case of a crash.

   *  `innodb_log_files_in_group'

     Options for innodb_log_files_in_group      *Command-Line        `--innodb_log_files_in_group=#'        
     Format*                              
     *Option-File Format* `innodb_log_files_in_group'        
     *Option Sets         Yes,            
     Variable*            `innodb_log_files_in_group'        
     *Variable Name*      `innodb_log_files_in_group'        
     *Variable Scope*     Global          
     *Dynamic Variable*   No              
                          *Permitted        
                          Values          
                          *               
     *Type*               `numeric'        
     *Default*            `2'             
     *Range*              `2 ..           
                          100'            


     The number of log files in the log group.  `InnoDB' writes to the
     files in a circular fashion. The default (and recommended) value
     is 2.

   *  `innodb_log_group_home_dir'

     Options for innodb_log_group_home_dir      *Command-Line        `--innodb_log_group_home_dir=path'        
     Format*                              
     *Option-File Format* `innodb_log_group_home_dir'        
     *Option Sets         Yes,            
     Variable*            `innodb_log_group_home_dir'        
     *Variable Name*      `innodb_log_group_home_dir'        
     *Variable Scope*     Global          
     *Dynamic Variable*   No              
                          *Permitted        
                          Values          
                          *               
     *Type*               `file           
                          name'           


     The directory path to the `InnoDB' log files.  If you do not
     specify any `InnoDB' log variables, the default is to create two
     5MB files names `ib_logfile0' and `ib_logfile1' in the MySQL data
     directory.

   *  `innodb_max_dirty_pages_pct'

     Options for innodb_max_dirty_pages_pct      *Command-Line        `--innodb_max_dirty_pages_pct=#'        
     Format*                              
     *Option-File Format* `innodb_max_dirty_pages_pct'        
     *Option Sets         Yes,            
     Variable*            `innodb_max_dirty_pages_pct'        
     *Variable Name*      `innodb_max_dirty_pages_pct'        
     *Variable Scope*     Global          
     *Dynamic Variable*   Yes             
                          *Permitted        
                          Values          
                          *               
     *Type*               `numeric'        
     *Default*            `90'            
     *Range*              `0 ..           
                          100'            


     This is an integer in the range from 0 to 100. The default value
     is 90. The main thread in `InnoDB' tries to write pages from the
     buffer pool so that the percentage of dirty (not yet written)
     pages will not exceed this value.

   *  `innodb_max_purge_lag'

     Options for innodb_max_purge_lag      *Command-Line        `--innodb_max_purge_lag=#'        
     Format*                              
     *Option-File Format* `innodb_max_purge_lag'        
     *Option Sets         Yes,            
     Variable*            `innodb_max_purge_lag'        
     *Variable Name*      `innodb_max_purge_lag'        
     *Variable Scope*     Global          
     *Dynamic Variable*   Yes             
                          *Permitted        
                          Values          
                          *               
     *Type*               `numeric'        
     *Default*            `0'             
     *Range*              `0 ..           
                          4294967295'        


     This variable controls how to delay *Note `INSERT': insert, *Note
     `UPDATE': update, and *Note `DELETE': delete. operations when purge
     operations are lagging (see *Note innodb-multi-versioning::). The
     default value 0 (no delays).

     The `InnoDB' transaction system maintains a list of transactions
     that have index records delete-marked by *Note `UPDATE': update. or
     *Note `DELETE': delete. operations. Let the length of this list be
     PURGE_LAG.  When PURGE_LAG exceeds `innodb_max_purge_lag', each
     *Note `INSERT': insert, *Note `UPDATE': update, and *Note
     `DELETE': delete. operation is delayed by
     ((PURGE_LAG/`innodb_max_purge_lag')x10)-5 milliseconds. The delay
     is computed in the beginning of a purge batch, every ten seconds.
     The operations are not delayed if purge cannot run because of an
     old consistent read view that could see the rows to be purged.

     A typical setting for a problematic workload might be 1 million,
     assuming that transactions are small, only 100 bytes in size, and
     it is permissible to have 100MB of unpurged `InnoDB' table rows.

     The lag value is displayed as the history list length in the
     `TRANSACTIONS' section of InnoDB Monitor output. For example, if
     the output includes the following lines, the lag value is 20:

          ------------
          TRANSACTIONS
          ------------
          Trx id counter 0 290328385
          Purge done for trx's n:o < 0 290315608 undo n:o < 0 17
          History list length 20

   *  `innodb_mirrored_log_groups'

     The number of identical copies of log groups to keep for the
     database. This should be set to 1.

   *  `innodb_open_files'

     Options for innodb_open_files      *Command-Line        `--innodb_open_files=#'        
     Format*                              
     *Option-File Format* `innodb_open_files'        
     *Variable Name*      `innodb_open_files'        
     *Variable Scope*     Global          
     *Dynamic Variable*   No              
                          *Permitted        
                          Values          
                          *               
     *Type*               `numeric'        
     *Default*            `300'           
     *Range*              `10 ..          
                          4294967295'        


     This variable is relevant only if you use multiple tablespaces in
     `InnoDB'. It specifies the maximum number of `.ibd' files that
     `InnoDB' can keep open at one time. The minimum value is 10. The
     default value is 300.

     The file descriptors used for `.ibd' files are for `InnoDB' only.
     They are independent of those specified by the
     `--open-files-limit' server option, and do not affect the
     operation of the table cache.

   *  `innodb_rollback_on_timeout'

     Options for innodb_rollback_on_timeout      *Version Introduced* 5.0.32          
     *Command-Line        `--innodb_rollback_on_timeout'        
     Format*                              
     *Option-File Format* `innodb_rollback_on_timeout'        
     *Option Sets         Yes,            
     Variable*            `innodb_rollback_on_timeout'        
     *Variable Name*      `innodb_rollback_on_timeout'        
     *Variable Scope*     Global          
     *Dynamic Variable*   No              
                          *Permitted        
                          Values          
                          *               
     *Type*               `boolean'        
     *Default*            `OFF'           


     In MySQL 5.0.13 and up, `InnoDB' rolls back only the last
     statement on a transaction timeout by default.  If
     `--innodb_rollback_on_timeout' is specified, a transaction timeout
     causes `InnoDB' to abort and roll back the entire transaction (the
     same behavior as before MySQL 5.0.13). This variable was added in
     MySQL 5.0.32.

   * `innodb-safe-binlog'

     Options for innodb-safe-binlog      *Version Removed*    5.0.3           
     *Version Deprecated* 5.0.3           
     *Command-Line        `--innodb-safe-binlog'        
     Format*                              
     *Option-File Format* `innodb-safe-binlog'        
     *Deprecated*         5.0.3           
                          *Permitted        
                          Values          
                          *               
     *Type*               `boolean'        


     If this option is given, then after a crash recovery by `InnoDB',
     *Note `mysqld': mysqld. truncates the binary log after the last
     not-rolled-back transaction in the log. The option also causes
     `InnoDB' to print an error if the binary log is smaller or shorter
     than it should be. See *Note binary-log::. This variable was
     removed in MySQL 5.0.3, having been made obsolete by the
     introduction of XA transaction support. You should set
     `innodb_support_xa' to `ON' or 1 to ensure consistency. See
     `innodb_support_xa'.

   *  `innodb_support_xa'

     Options for innodb_support_xa      *Version Introduced* 5.0.3           
     *Command-Line        `--innodb_support_xa'        
     Format*                              
     *Option-File Format* `innodb_support_xa'        
     *Option Sets         Yes,            
     Variable*            `innodb_support_xa'        
     *Variable Name*      `innodb_support_xa'        
     *Variable Scope*     Global,         
                          Session         
     *Dynamic Variable*   Yes             
                          *Permitted        
                          Values          
                          *               
     *Type*               `boolean'        
     *Default*            `TRUE'          


     Enables `InnoDB' support for two-phase commit in XA transactions,
     causing an extra disk flush for transaction preparation. This
     setting is the default. The XA mechanism is used internally and is
     essential for any server that has its binary log turned on and is
     accepting changes to its data from more than one thread. If you
     turn it off, transactions can be written to the binary log in a
     different order from the one in which the live database is
     committing them. This can produce different data when the binary
     log is replayed in disaster recovery or on a replication slave. Do
     not turn it off on a replication master server unless you have an
     unusual setup where only one thread is able to change data.

     For a server that is accepting data changes from only one thread,
     it is safe and recommended to turn off this option to improve
     performance for *Note `InnoDB': innodb-storage-engine.  tables.
     For example, you can turn it off on replication slaves where only
     the replication SQL thread is changing data.

     You can also turn off this option if you do not need it for safe
     binary logging or replication, and you also do not use an external
     XA transaction manager.

     This variable was added in MySQL 5.0.3.

   *  `innodb_sync_spin_loops'

     Options for innodb_sync_spin_loops      *Version Introduced* 5.0.3           
     *Command-Line        `--innodb_sync_spin_loops=#'        
     Format*                              
     *Option-File Format* `innodb_sync_spin_loops'        
     *Option Sets         Yes,            
     Variable*            `innodb_sync_spin_loops'        
     *Variable Name*      `innodb_sync_spin_loops'        
     *Variable Scope*     Global          
     *Dynamic Variable*   Yes             


     The number of times a thread waits for an `InnoDB' mutex to be
     freed before the thread is suspended. The default value is 20.
     This variable was added in MySQL 5.0.3.

   *  `innodb_table_locks'

     Options for innodb_table_locks      *Command-Line        `--innodb_table_locks'        
     Format*                              
     *Option-File Format* `innodb_table_locks'        
     *Option Sets         Yes,            
     Variable*            `innodb_table_locks'        
     *Variable Name*      `innodb_table_locks'        
     *Variable Scope*     Global,         
                          Session         
     *Dynamic Variable*   Yes             
                          *Permitted        
                          Values          
                          *               
     *Type*               `boolean'        
     *Default*            `TRUE'          


     If `autocommit = 0', `InnoDB' honors *Note `LOCK TABLES':
     lock-tables.; MySQL does not return from `LOCK TABLES ... WRITE'
     until all other threads have released all their locks to the
     table. The default value of `innodb_table_locks' is 1, which means
     that *Note `LOCK TABLES': lock-tables.  causes InnoDB to lock a
     table internally if `autocommit = 0'.

   *  `innodb_thread_concurrency'

     Options for innodb_thread_concurrency      *Command-Line        `--innodb_thread_concurrency=#'        
     Format*                              
     *Option-File Format* `innodb_thread_concurrency'        
     *Option Sets         Yes,            
     Variable*            `innodb_thread_concurrency'        
     *Variable Name*      `innodb_thread_concurrency'        
     *Variable Scope*     Global          
     *Dynamic Variable*   Yes             
                          *Permitted        
                          Values          
                          (>=             
                          5.0.9)*         
     *Type*               `numeric'        
     *Default*            `20'            
     *Range*              `1 ..           
                          1000'           
                          *Permitted        
                          Values          
                          (>=             
                          5.0.19)*        
     *Type*               `numeric'        
     *Default*            `8'             
     *Range*              `0 ..           
                          1000'           


     `InnoDB' tries to keep the number of operating system threads
     concurrently inside `InnoDB' less than or equal to the limit given
     by this variable. Once the number of threads reaches this limit,
     additional threads are placed into a wait state within a FIFO
     queue for execution. Threads waiting for locks are not counted in
     the number of concurrently executing threads.

     The correct value for this variable is dependent on environment
     and workload. You will need to try a range of different values to
     determine what value works for your applications. A recommended
     value is 2 times the number of CPUs plus the number of disks.

     The range of this variable is 0 to 1000. A value of 20 or higher
     is interpreted as infinite concurrency before MySQL 5.0.19. From
     5.0.19 on, you can disable thread concurrency checking by setting
     the value to 0. Disabling thread concurrency checking enables
     InnoDB to create as many threads as it needs.

     The default value has changed several times: 8 before MySQL 5.0.8,
     20 (infinite) from 5.0.8 through 5.0.18, 0 (infinite) from 5.0.19
     to 5.0.20, and 8 (finite) from 5.0.21 on.

   *  `innodb_thread_sleep_delay'

     Options for innodb_thread_sleep_delay      *Version Introduced* 5.0.3           
     *Command-Line        `--innodb_thread_sleep_delay=#'        
     Format*                              
     *Option-File Format* `innodb_thread_sleep_delay'        
     *Option Sets         Yes,            
     Variable*            `innodb_thread_sleep_delay'        
     *Variable Name*      `innodb_thread_sleep_delay'        
     *Variable Scope*     Global          
     *Dynamic Variable*   Yes             
                          *Permitted        
                          Values          
                          (>=             
                          5.0.8,          
                          <=              
                          5.0.18)*        
     *Type*               `numeric'        
     *Default*            `0'             
     *Range*              `1000           
                          ..              
                          4294967295'        
                          *Permitted        
                          Values          
                          (>=             
                          5.0.19,         
                          <=              
                          5.0.20)*        
     *Type*               `numeric'        
     *Default*            `0'             
     *Range*              `1000           
                          ..              
                          4294967295'        
                          *Permitted        
                          Values          
                          (>=             
                          5.0.21)*        
     *Type*               `numeric'        
     *Default*            `8'             


     How long `InnoDB' threads sleep before joining the `InnoDB' queue,
     in microseconds.  The default value is 10,000. A value of 0
     disables sleep. This variable was added in MySQL 5.0.3.

   *  `innodb_use_legacy_cardinality_algorithm'

     Options for innodb_use_legacy_cardinality_algorithm      *Version Introduced* 5.0.82          
     *Command-Line        `--innodb_use_legacy_cardinality_algorithm=#'        
     Format*                              
     *Option-File Format* `innodb_use_legacy_cardinality_algorithm'        
     *Option Sets         Yes,            
     Variable*            `innodb_use_legacy_cardinality_algorithm'        
     *Variable Name*      `innodb_use_legacy_cardinality_algorithm'        
     *Variable Scope*     Global          
     *Dynamic Variable*   Yes             
                          *Permitted        
                          Values          
                          *               
     *Type*               `boolean'        
     *Default*            `ON'            


     *Note `InnoDB': innodb-storage-engine. uses random numbers to
     generate dives into indexes for calculating index cardinality.
     However, under certain conditions, the algorithm does not generate
     random numbers, so *Note `ANALYZE TABLE': analyze-table. sometimes
     does not update cardinality estimates properly. An alternative
     algorithm was introduced in MySQL 5.0.82 with better randomization
     properties, and the `innodb_use_legacy_cardinality_algorithm',
     system variable which algorithm to use. The default value of the
     variable is 1 (`ON'), to use the original algorithm for
     compatibility with existing applications. The variable can be set
     to 0 (`OFF') to use the new algorithm with improved randomness.

   * `sync_binlog'

     Options for sync_binlog      *Version Introduced* 5.0.1           
     *Command-Line        `--sync-binlog=#'        
     Format*                              
     *Option-File Format* `sync_binlog'        
     *Option Sets         Yes,            
     Variable*            `sync_binlog'        
     *Variable Name*      `sync_binlog'        
     *Variable Scope*     Global          
     *Dynamic Variable*   Yes             
                          *Permitted        
                          Values          
                          *               
     *Platform Bit Size*  `32'            
     *Type*               `numeric'        
     *Default*            `0'             
     *Range*              `0 ..           
                          4294967295'        
                          *Permitted        
                          Values          
                          *               
     *Platform Bit Size*  `64'            
     *Type*               `numeric'        
     *Default*            `0'             
     *Range*              `0 ..           
                          18446744073709547520'        


     If the value of this variable is greater than 0, the MySQL server
     synchronizes its binary log to disk (using `fdatasync()') after
     every `sync_binlog' writes to the binary log. There is one write
     to the binary log per statement if autocommit is enabled, and one
     write per transaction otherwise. The default value of
     `sync_binlog' is 0, which does no synchronizing to disk. A value
     of 1 is the safest choice, because in the event of a crash you
     lose at most one statement or transaction from the binary log.
     However, it is also the slowest choice (unless the disk has a
     battery-backed cache, which makes synchronization very fast).


File: manual.info,  Node: using-innodb-tables,  Next: innodb-data-log-reconfiguration,  Prev: innodb-parameters,  Up: innodb-storage-engine

14.2.4 Creating and Using `InnoDB' Tables
-----------------------------------------

* Menu:

* innodb-transactions-with-different-apis::  How to Use Transactions in `InnoDB' with Different APIs
* converting-tables-to-innodb::  Converting Tables from Other Storage Engines to `InnoDB'
* innodb-auto-increment-handling::  `AUTO_INCREMENT' Handling in `InnoDB'
* innodb-foreign-key-constraints::  `FOREIGN KEY' Constraints
* innodb-and-mysql-replication::  `InnoDB' and MySQL Replication

To create an `InnoDB' table, specify an `ENGINE = InnoDB' option in the
*Note `CREATE TABLE': create-table. statement:

     CREATE TABLE customers (a INT, b CHAR (20), INDEX (a)) ENGINE=InnoDB;

The older term `TYPE' is supported as a synonym for `ENGINE' for
backward compatibility, but `ENGINE' is the preferred term and `TYPE'
is deprecated.

The statement creates a table and an index on column `a' in the
`InnoDB' tablespace that consists of the data files that you specified
in `my.cnf'. In addition, MySQL creates a file `customers.frm' in the
`test' directory under the MySQL database directory. Internally,
`InnoDB' adds an entry for the table to its own data dictionary. The
entry includes the database name. For example, if `test' is the
database in which the `customers' table is created, the entry is for
`'test/customers''.  This means you can create a table of the same name
`customers' in some other database, and the table names do not collide
inside `InnoDB'.

You can query the amount of free space in the `InnoDB' tablespace by
issuing a *Note `SHOW TABLE STATUS': show-table-status. statement for
any `InnoDB' table. The amount of free space in the tablespace appears
in the `Comment' section in the output of *Note `SHOW TABLE STATUS':
show-table-status.  For example:

     SHOW TABLE STATUS FROM test LIKE 'customers'

The statistics *Note `SHOW': show. displays for `InnoDB' tables are
only approximate. They are used in SQL optimization. Table and index
reserved sizes in bytes are accurate, though.


File: manual.info,  Node: innodb-transactions-with-different-apis,  Next: converting-tables-to-innodb,  Prev: using-innodb-tables,  Up: using-innodb-tables

14.2.4.1 How to Use Transactions in `InnoDB' with Different APIs
................................................................

By default, each client that connects to the MySQL server begins with
autocommit mode enabled, which automatically commits every SQL
statement as you execute it. To use multiple-statement transactions,
you can switch autocommit off with the SQL statement `SET autocommit =
0' and end each transaction with either *Note `COMMIT': commit. or
*Note `ROLLBACK': commit. If you want to leave autocommit on, you can
begin your transactions within *Note `START TRANSACTION': commit. and
end them with *Note `COMMIT': commit. or *Note `ROLLBACK': commit. The
following example shows two transactions. The first is committed; the
second is rolled back.

     shell> mysql test

     mysql> CREATE TABLE customer (a INT, b CHAR (20), INDEX (a))
         -> ENGINE=InnoDB;
     Query OK, 0 rows affected (0.00 sec)
     mysql> START TRANSACTION;
     Query OK, 0 rows affected (0.00 sec)
     mysql> INSERT INTO customer VALUES (10, 'Heikki');
     Query OK, 1 row affected (0.00 sec)
     mysql> COMMIT;
     Query OK, 0 rows affected (0.00 sec)
     mysql> SET autocommit=0;
     Query OK, 0 rows affected (0.00 sec)
     mysql> INSERT INTO customer VALUES (15, 'John');
     Query OK, 1 row affected (0.00 sec)
     mysql> ROLLBACK;
     Query OK, 0 rows affected (0.00 sec)
     mysql> SELECT * FROM customer;
     +------+--------+
     | a    | b      |
     +------+--------+
     |   10 | Heikki |
     +------+--------+
     1 row in set (0.00 sec)
     mysql>

In APIs such as PHP, Perl DBI, JDBC, ODBC, or the standard C call
interface of MySQL, you can send transaction control statements such as
*Note `COMMIT': commit. to the MySQL server as strings just like any
other SQL statements such as *Note `SELECT': select. or *Note `INSERT':
insert. Some APIs also offer separate special transaction commit and
rollback functions or methods.


File: manual.info,  Node: converting-tables-to-innodb,  Next: innodb-auto-increment-handling,  Prev: innodb-transactions-with-different-apis,  Up: using-innodb-tables

14.2.4.2 Converting Tables from Other Storage Engines to `InnoDB'
.................................................................

To convert a non-`InnoDB' table to use `InnoDB' use *Note `ALTER
TABLE': alter-table.:

     ALTER TABLE t1 ENGINE=InnoDB;

*Important*:

Do not convert MySQL system tables in the `mysql' database (such as
`user' or `host') to the `InnoDB' type. This is an unsupported
operation. The system tables must always be of the `MyISAM' type.

`InnoDB' does not have a special optimization for separate index
creation the way the `MyISAM' storage engine does. Therefore, it does
not pay to export and import the table and create indexes afterward.
The fastest way to alter a table to `InnoDB' is to do the inserts
directly to an `InnoDB' table. That is, use `ALTER TABLE ...
ENGINE=INNODB', or create an empty `InnoDB' table with identical
definitions and insert the rows with `INSERT INTO ... SELECT * FROM
...'.

If you have `UNIQUE' constraints on secondary keys, you can speed up a
table import by turning off the uniqueness checks temporarily during
the import operation:

     SET unique_checks=0;... IMPORT OPERATION ...
     SET unique_checks=1;

For big tables, this saves a lot of disk I/O because `InnoDB' can then
use its insert buffer to write secondary index records as a batch. Be
certain that the data contains no duplicate keys.  `unique_checks'
permits but does not require storage engines to ignore duplicate keys.

To get better control over the insertion process, it might be good to
insert big tables in pieces:

     INSERT INTO newtable SELECT * FROM oldtable
        WHERE yourkey > something AND yourkey <= somethingelse;

After all records have been inserted, you can rename the tables.

During the conversion of big tables, you should increase the size of
the `InnoDB' buffer pool to reduce disk I/O. Do not use more than 80%
of the physical memory, though.  You can also increase the sizes of the
`InnoDB' log files.

Make sure that you do not fill up the tablespace: `InnoDB' tables
require a lot more disk space than `MyISAM' tables. If an *Note `ALTER
TABLE': alter-table. operation runs out of space, it starts a rollback,
and that can take hours if it is disk-bound. For inserts, `InnoDB' uses
the insert buffer to merge secondary index records to indexes in
batches. That saves a lot of disk I/O. For rollback, no such mechanism
is used, and the rollback can take 30 times longer than the insertion.

In the case of a runaway rollback, if you do not have valuable data in
your database, it may be advisable to kill the database process rather
than wait for millions of disk I/O operations to complete. For the
complete procedure, see *Note forcing-innodb-recovery::.

If you want all your (nonsystem) tables to be created as `InnoDB'
tables, add the line `default-storage-engine=innodb' to the `[mysqld]'
section of your server option file.


File: manual.info,  Node: innodb-auto-increment-handling,  Next: innodb-foreign-key-constraints,  Prev: converting-tables-to-innodb,  Up: using-innodb-tables

14.2.4.3 `AUTO_INCREMENT' Handling in `InnoDB'
..............................................

If you specify an `AUTO_INCREMENT' column for an `InnoDB' table, the
table handle in the `InnoDB' data dictionary contains a special counter
called the auto-increment counter that is used in assigning new values
for the column. This counter is stored only in main memory, not on disk.

`InnoDB' uses the following algorithm to initialize the auto-increment
counter for a table `t' that contains an `AUTO_INCREMENT' column named
`ai_col': After a server startup, for the first insert into a table `t',
`InnoDB' executes the equivalent of this statement:

     SELECT MAX(ai_col) FROM t FOR UPDATE;

`InnoDB' increments by one the value retrieved by the statement and
assigns it to the column and to the auto-increment counter for the
table. If the table is empty, `InnoDB' uses the value `1'.  If a user
invokes a *Note `SHOW TABLE STATUS': show-table-status. statement that
displays output for the table `t' and the auto-increment counter has
not been initialized, `InnoDB' initializes but does not increment the
value and stores it for use by later inserts. This initialization uses
a normal exclusive-locking read on the table and the lock lasts to the
end of the transaction.

`InnoDB' follows the same procedure for initializing the auto-increment
counter for a freshly created table.

After the auto-increment counter has been initialized, if a user does
not explicitly specify a value for an `AUTO_INCREMENT' column, `InnoDB'
increments the counter by one and assigns the new value to the column.
If the user inserts a row that explicitly specifies the column value,
and the value is bigger than the current counter value, the counter is
set to the specified column value.

When accessing the auto-increment counter, `InnoDB' uses a special
table-level `AUTO-INC' lock that it keeps to the end of the current SQL
statement, not to the end of the transaction. The special lock release
strategy was introduced to improve concurrency for inserts into a table
containing an `AUTO_INCREMENT' column. Nevertheless, two transactions
cannot have the `AUTO-INC' lock on the same table simultaneously, which
can have a performance impact if the `AUTO-INC' lock is held for a long
time. That might be the case for a statement such as `INSERT INTO t1
... SELECT ... FROM t2' that inserts all rows from one table into
another.

`InnoDB' uses the in-memory auto-increment counter as long as the
server runs. When the server is stopped and restarted, `InnoDB'
reinitializes the counter for each table for the first *Note `INSERT':
insert. to the table, as described earlier.

You may see gaps in the sequence of values assigned to the
`AUTO_INCREMENT' column if you roll back transactions that have
generated numbers using the counter.

If a user specifies `NULL' or `0' for the `AUTO_INCREMENT' column in an
*Note `INSERT': insert, `InnoDB' treats the row as if the value had not
been specified and generates a new value for it.

The behavior of the auto-increment mechanism is not defined if a user
assigns a negative value to the column or if the value becomes bigger
than the maximum integer that can be stored in the specified integer
type.

An `AUTO_INCREMENT' column must appear as the first column in an index
on an `InnoDB' table.

Beginning with MySQL 5.0.3, `InnoDB' supports the `AUTO_INCREMENT = N'
table option in *Note `CREATE TABLE': create-table. and *Note `ALTER
TABLE': alter-table. statements, to set the initial counter value or
alter the current counter value.  The effect of this option is canceled
by a server restart, for reasons discussed earlier in this section.


File: manual.info,  Node: innodb-foreign-key-constraints,  Next: innodb-and-mysql-replication,  Prev: innodb-auto-increment-handling,  Up: using-innodb-tables

14.2.4.4 `FOREIGN KEY' Constraints
..................................

`InnoDB' supports foreign key constraints. The syntax for a foreign key
constraint definition in `InnoDB' looks like this:

     [CONSTRAINT [SYMBOL]] FOREIGN KEY
         [INDEX_NAME] (INDEX_COL_NAME, ...)
         REFERENCES TBL_NAME (INDEX_COL_NAME,...)
         [ON DELETE REFERENCE_OPTION]
         [ON UPDATE REFERENCE_OPTION]

     REFERENCE_OPTION:
         RESTRICT | CASCADE | SET NULL | NO ACTION

INDEX_NAME represents a foreign key ID. If given, this is ignored if an
index for the foreign key is defined explicitly. Otherwise, if `InnoDB'
creates an index for the foreign key, it uses INDEX_NAME for the index
name.

Foreign keys definitions are subject to the following conditions:

   * Both tables must be `InnoDB' tables and they must not be
     `TEMPORARY' tables.

   * Corresponding columns in the foreign key and the referenced key
     must have similar internal data types inside `InnoDB' so that they
     can be compared without a type conversion. _The size and sign of
     integer types must be the same_. The length of string types need
     not be the same. For nonbinary (character) string columns, the
     character set and collation must be the same.

   * `InnoDB' requires indexes on foreign keys and referenced keys so
     that foreign key checks can be fast and not require a table scan.
     In the referencing table, there must be an index where the foreign
     key columns are listed as the _first_ columns in the same order.
     Such an index is created on the referencing table automatically if
     it does not exist. (This is in contrast to some older versions, in
     which indexes had to be created explicitly or the creation of
     foreign key constraints would fail.) INDEX_NAME, if given, is used
     as described previously.

   * `InnoDB' permits a foreign key to reference any index column or
     group of columns. However, in the referenced table, there must be
     an index where the referenced columns are listed as the _first_
     columns in the same order.

   * Index prefixes on foreign key columns are not supported. One
     consequence of this is that *Note `BLOB': blob. and *Note `TEXT':
     blob. columns cannot be included in a foreign key because indexes
     on those columns must always include a prefix length.

   * If the `CONSTRAINT SYMBOL' clause is given, the SYMBOL value must
     be unique in the database. If the clause is not given, `InnoDB'
     creates the name automatically.

`InnoDB' rejects any *Note `INSERT': insert. or *Note `UPDATE': update.
operation that attempts to create a foreign key value in a child table
if there is no a matching candidate key value in the parent table. The
action `InnoDB' takes for any *Note `UPDATE': update. or *Note
`DELETE': delete. operation that attempts to update or delete a
candidate key value in the parent table that has some matching rows in
the child table is dependent on the _referential action_ specified using
`ON UPDATE' and `ON DELETE' subclauses of the `FOREIGN KEY' clause. When
the user attempts to delete or update a row from a parent table, and
there are one or more matching rows in the child table, `InnoDB'
supports five options regarding the action to be taken. If `ON DELETE'
or `ON UPDATE' are not specified, the default action is `RESTRICT'.

   * `CASCADE': Delete or update the row from the parent table and
     automatically delete or update the matching rows in the child
     table. Both `ON DELETE CASCADE' and `ON UPDATE CASCADE' are
     supported. Between two tables, you should not define several `ON
     UPDATE CASCADE' clauses that act on the same column in the parent
     table or in the child table.

     *Note*:

     Currently, cascaded foreign key actions do not activate triggers.

   * `SET NULL': Delete or update the row from the parent table and set
     the foreign key column or columns in the child table to `NULL'.
     This is valid only if the foreign key columns do not have the `NOT
     NULL' qualifier specified. Both `ON DELETE SET NULL' and `ON
     UPDATE SET NULL' clauses are supported.

     If you specify a `SET NULL' action, _make sure that you have not
     declared the columns in the child table as `NOT NULL'_.

   * `NO ACTION': In standard SQL, `NO ACTION' means _no action_ in the
     sense that an attempt to delete or update a primary key value is
     not permitted to proceed if there is a related foreign key value
     in the referenced table.  `InnoDB' rejects the delete or update
     operation for the parent table.

   * `RESTRICT': Rejects the delete or update operation for the parent
     table. Specifying `RESTRICT' (or `NO ACTION') is the same as
     omitting the `ON DELETE' or `ON UPDATE' clause.  (Some database
     systems have deferred checks, and `NO ACTION' is a deferred check.
     In MySQL, foreign key constraints are checked immediately, so `NO
     ACTION' is the same as `RESTRICT'.)

   * `SET DEFAULT': This action is recognized by the parser, but
     `InnoDB' rejects table definitions containing `ON DELETE SET
     DEFAULT' or `ON UPDATE SET DEFAULT' clauses.

`InnoDB' supports foreign key references within a table. In these
cases, `child table records' really refers to dependent records within
the same table.

Here is a simple example that relates `parent' and `child' tables
through a single-column foreign key:

     CREATE TABLE parent (id INT NOT NULL,
                          PRIMARY KEY (id)
     ) ENGINE=INNODB;
     CREATE TABLE child (id INT, parent_id INT,
                         INDEX par_ind (parent_id),
                         FOREIGN KEY (parent_id) REFERENCES parent(id)
                           ON DELETE CASCADE
     ) ENGINE=INNODB;

A more complex example in which a `product_order' table has foreign
keys for two other tables. One foreign key references a two-column
index in the `product' table. The other references a single-column
index in the `customer' table:

     CREATE TABLE product (category INT NOT NULL, id INT NOT NULL,
                           price DECIMAL,
                           PRIMARY KEY(category, id)) ENGINE=INNODB;
     CREATE TABLE customer (id INT NOT NULL,
                            PRIMARY KEY (id)) ENGINE=INNODB;
     CREATE TABLE product_order (no INT NOT NULL AUTO_INCREMENT,
                                 product_category INT NOT NULL,
                                 product_id INT NOT NULL,
                                 customer_id INT NOT NULL,
                                 PRIMARY KEY(no),
                                 INDEX (product_category, product_id),
                                 FOREIGN KEY (product_category, product_id)
                                   REFERENCES product(category, id)
                                   ON UPDATE CASCADE ON DELETE RESTRICT,
                                 INDEX (customer_id),
                                 FOREIGN KEY (customer_id)
                                   REFERENCES customer(id)) ENGINE=INNODB;

`InnoDB' enables you to add a new foreign key constraint to a table by
using *Note `ALTER TABLE': alter-table.:

     ALTER TABLE TBL_NAME
         ADD [CONSTRAINT [SYMBOL]] FOREIGN KEY
         [INDEX_NAME] (INDEX_COL_NAME, ...)
         REFERENCES TBL_NAME (INDEX_COL_NAME,...)
         [ON DELETE REFERENCE_OPTION]
         [ON UPDATE REFERENCE_OPTION]

The foreign key can be self referential (referring to the same table).
When you add a foreign key constraint to a table using *Note `ALTER
TABLE': alter-table, _remember to create the required indexes first._

`InnoDB' supports the use of *Note `ALTER TABLE': alter-table. to drop
foreign keys:

     ALTER TABLE TBL_NAME DROP FOREIGN KEY FK_SYMBOL;

If the `FOREIGN KEY' clause included a `CONSTRAINT' name when you
created the foreign key, you can refer to that name to drop the foreign
key.  Otherwise, the FK_SYMBOL value is internally generated by
`InnoDB' when the foreign key is created. To find out the symbol value
when you want to drop a foreign key, use the *Note `SHOW CREATE TABLE':
show-create-table. statement. For example:

     mysql> SHOW CREATE TABLE ibtest11c\G
     *************************** 1. row ***************************
            Table: ibtest11c
     Create Table: CREATE TABLE `ibtest11c` (
       `A` int(11) NOT NULL auto_increment,
       `D` int(11) NOT NULL default '0',
       `B` varchar(200) NOT NULL default '',
       `C` varchar(175) default NULL,
       PRIMARY KEY  (`A`,`D`,`B`),
       KEY `B` (`B`,`C`),
       KEY `C` (`C`),
       CONSTRAINT `0_38775` FOREIGN KEY (`A`, `D`)
     REFERENCES `ibtest11a` (`A`, `D`)
     ON DELETE CASCADE ON UPDATE CASCADE,
       CONSTRAINT `0_38776` FOREIGN KEY (`B`, `C`)
     REFERENCES `ibtest11a` (`B`, `C`)
     ON DELETE CASCADE ON UPDATE CASCADE
     ) ENGINE=INNODB CHARSET=latin1
     1 row in set (0.01 sec)

     mysql> ALTER TABLE ibtest11c DROP FOREIGN KEY `0_38775`;

You cannot add a foreign key and drop a foreign key in separate clauses
of a single *Note `ALTER TABLE': alter-table.  statement. Separate
statements are required.

If *Note `ALTER TABLE': alter-table. for an `InnoDB' table results in
changes to column values (for example, because a column is truncated),
`InnoDB''s `FOREIGN KEY' constraint checks do not notice possible
violations caused by changing the values.

The `InnoDB' parser permits table and column identifiers in a `FOREIGN
KEY ... REFERENCES ...' clause to be quoted within backticks.
(Alternatively, double quotation marks can be used if the `ANSI_QUOTES'
SQL mode is enabled.) The `InnoDB' parser also takes into account the
setting of the `lower_case_table_names' system variable.

`InnoDB' returns a table's foreign key definitions as part of the
output of the *Note `SHOW CREATE TABLE': show-create-table. statement:

     SHOW CREATE TABLE TBL_NAME;

*Note `mysqldump': mysqldump. also produces correct definitions of
tables in the dump file, and does not forget about the foreign keys.

You can also display the foreign key constraints for a table like this:

     SHOW TABLE STATUS FROM DB_NAME LIKE 'TBL_NAME';

The foreign key constraints are listed in the `Comment' column of the
output.

When performing foreign key checks, `InnoDB' sets shared row-level
locks on child or parent records it has to look at. `InnoDB' checks
foreign key constraints immediately; the check is not deferred to
transaction commit.

To make it easier to reload dump files for tables that have foreign key
relationships, *Note `mysqldump': mysqldump.  automatically includes a
statement in the dump output to set `foreign_key_checks' to 0. This
avoids problems with tables having to be reloaded in a particular order
when the dump is reloaded. It is also possible to set this variable
manually:

     mysql> SET foreign_key_checks = 0;
     mysql> SOURCE DUMP_FILE_NAME;
     mysql> SET foreign_key_checks = 1;

This enables you to import the tables in any order if the dump file
contains tables that are not correctly ordered for foreign keys. It
also speeds up the import operation. Setting `foreign_key_checks' to 0
can also be useful for ignoring foreign key constraints during *Note
`LOAD DATA': load-data. and *Note `ALTER TABLE': alter-table.
operations. However, even if `foreign_key_checks = 0', InnoDB does not
permit the creation of a foreign key constraint where a column
references a nonmatching column type. Also, if an `InnoDB' table has
foreign key constraints, *Note `ALTER TABLE': alter-table. cannot be
used to change the table to use another storage engine. To alter the
storage engine, you must drop any foreign key constraints first.

`InnoDB' does not permit you to drop a table that is referenced by a
`FOREIGN KEY' constraint, unless you do `SET foreign_key_checks = 0'.
When you drop a table, the constraints that were defined in its create
statement are also dropped.

If you re-create a table that was dropped, it must have a definition
that conforms to the foreign key constraints referencing it. It must
have the right column names and types, and it must have indexes on the
referenced keys, as stated earlier. If these are not satisfied, MySQL
returns error number 1005 and refers to error 150 in the error message.

If MySQL reports an error number 1005 from a *Note `CREATE TABLE':
create-table. statement, and the error message refers to error 150,
table creation failed because a foreign key constraint was not
correctly formed. Similarly, if an *Note `ALTER TABLE': alter-table.
fails and it refers to error 150, that means a foreign key definition
would be incorrectly formed for the altered table. You can use *Note
`SHOW ENGINE INNODB STATUS': show-engine. to display a detailed
explanation of the most recent `InnoDB' foreign key error in the server.

*Important*:

For users familiar with the ANSI/ISO SQL Standard, please note that no
storage engine, including `InnoDB', recognizes or enforces the `MATCH'
clause used in referential-integrity constraint definitions. Use of an
explicit `MATCH' clause will not have the specified effect, and also
causes `ON DELETE' and `ON UPDATE' clauses to be ignored. For these
reasons, specifying `MATCH' should be avoided.

The `MATCH' clause in the SQL standard controls how `NULL' values in a
composite (multiple-column) foreign key are handled when comparing to a
primary key. `InnoDB' essentially implements the semantics defined by
`MATCH SIMPLE', which permit a foreign key to be all or partially
`NULL'. In that case, the (child table) row containing such a foreign
key is permitted to be inserted, and does not match any row in the
referenced (parent) table. It is possible to implement other semantics
using triggers.

Additionally, MySQL and `InnoDB' require that the referenced columns be
indexed for performance. However, the system does not enforce a
requirement that the referenced columns be `UNIQUE' or be declared `NOT
NULL'. The handling of foreign key references to nonunique keys or keys
that contain `NULL' values is not well defined for operations such as
*Note `UPDATE': update. or `DELETE CASCADE'. You are advised to use
foreign keys that reference only `UNIQUE' and `NOT NULL' keys.

Furthermore, `InnoDB' does not recognize or support `inline `REFERENCES'
specifications' (as defined in the SQL standard) where the references
are defined as part of the column specification. `InnoDB' accepts
`REFERENCES' clauses only when specified as part of a separate `FOREIGN
KEY' specification. For other storage engines, MySQL Server parses and
ignores foreign key specifications.

*Deviation from SQL standards*: If there are several rows in the parent
table that have the same referenced key value, `InnoDB' acts in foreign
key checks as if the other parent rows with the same key value do not
exist. For example, if you have defined a `RESTRICT' type constraint,
and there is a child row with several parent rows, `InnoDB' does not
permit the deletion of any of those parent rows.

`InnoDB' performs cascading operations through a depth-first algorithm,
based on records in the indexes corresponding to the foreign key
constraints.

*Deviation from SQL standards*: A `FOREIGN KEY' constraint that
references a non-`UNIQUE' key is not standard SQL. It is an `InnoDB'
extension to standard SQL.

*Deviation from SQL standards*: If `ON UPDATE CASCADE' or `ON UPDATE
SET NULL' recurses to update the _same table_ it has previously updated
during the cascade, it acts like `RESTRICT'. This means that you cannot
use self-referential `ON UPDATE CASCADE' or `ON UPDATE SET NULL'
operations. This is to prevent infinite loops resulting from cascaded
updates. A self-referential `ON DELETE SET NULL', on the other hand, is
possible, as is a self-referential `ON DELETE CASCADE'. Cascading
operations may not be nested more than 15 levels deep.

*Deviation from SQL standards*: Like MySQL in general, in an SQL
statement that inserts, deletes, or updates many rows, `InnoDB' checks
`UNIQUE' and `FOREIGN KEY' constraints row-by-row. According to the SQL
standard, the default behavior should be deferred checking. That is,
constraints are only checked after the _entire SQL statement_ has been
processed. Until `InnoDB' implements deferred constraint checking, some
things will be impossible, such as deleting a record that refers to
itself using a foreign key.


File: manual.info,  Node: innodb-and-mysql-replication,  Prev: innodb-foreign-key-constraints,  Up: using-innodb-tables

14.2.4.5 `InnoDB' and MySQL Replication
.......................................

MySQL replication works for `InnoDB' tables as it does for `MyISAM'
tables. It is also possible to use replication in a way where the
storage engine on the slave is not the same as the original storage
engine on the master. For example, you can replicate modifications to an
`InnoDB' table on the master to a `MyISAM' table on the slave.

To set up a new slave for a master, you have to make a copy of the
`InnoDB' tablespace and the log files, as well as the `.frm' files of
the `InnoDB' tables, and move the copies to the slave. If the
`innodb_file_per_table' variable is enabled, you must also copy the
`.ibd' files as well. For the proper procedure to do this, see *Note
innodb-backup::.

If you can shut down the master or an existing slave, you can take a
cold backup of the `InnoDB' tablespace and log files and use that to
set up a slave. To make a new slave without taking down any server you
can also use the commercial `InnoDB' Hot Backup tool
(http://www.innodb.com/wp/products/hot-backup/).

You cannot set up replication for `InnoDB' using the *Note `LOAD TABLE
FROM MASTER': load-table-from-master.  statement, which works only for
`MyISAM' tables. There are two possible workarounds:

   * Dump the table on the master and import the dump file into the
     slave.

   * Use `ALTER TABLE TBL_NAME ENGINE=MyISAM' on the master before
     setting up replication with `LOAD TABLE TBL_NAME FROM MASTER', and
     then use *Note `ALTER TABLE': alter-table. to convert the master
     table back to `InnoDB' afterward. However, this should not be done
     for tables that have foreign key definitions because the
     definitions will be lost.

Transactions that fail on the master do not affect replication at all.
MySQL replication is based on the binary log where MySQL writes SQL
statements that modify data. A transaction that fails (for example,
because of a foreign key violation, or because it is rolled back) is
not written to the binary log, so it is not sent to slaves. See *Note
commit::.

Replication and `CASCADE'

Cascading actions for `InnoDB' tables on the master are replicated on
the slave _only_ if the tables sharing the foreign key relation use
`InnoDB' on both the master and slave.  Suppose that you have started
replication, and then create two tables on the master using the
following *Note `CREATE TABLE': create-table. statements:

     CREATE TABLE fc1 (
         i INT PRIMARY KEY,
         j INT
     ) ENGINE = InnoDB;

     CREATE TABLE fc2 (
         m INT PRIMARY KEY,
         n INT,
         FOREIGN KEY ni (n) REFERENCES fc1 (i)
             ON DELETE CASCADE
     ) ENGINE = InnoDB;

Suppose that the slave does not have `InnoDB' support enabled. If this
is the case, then the tables on the slave are created, but they use the
`MyISAM' storage engine, and the `FOREIGN KEY' option is ignored. Now
we insert some rows into the tables on the master:

     master> INSERT INTO fc1 VALUES (1, 1), (2, 2);
     Query OK, 2 rows affected (0.09 sec)
     Records: 2  Duplicates: 0  Warnings: 0

     master> INSERT INTO fc2 VALUES (1, 1), (2, 2), (3, 1);
     Query OK, 3 rows affected (0.19 sec)
     Records: 3  Duplicates: 0  Warnings: 0

At this point, on both the master and the slave, table `fc1' contains 2
rows, and table `fc2' contains 3 rows, as shown here:

     master> SELECT * FROM fc1;
     +---+------+
     | i | j    |
     +---+------+
     | 1 |    1 |
     | 2 |    2 |
     +---+------+
     2 rows in set (0.00 sec)

     master> SELECT * FROM fc2;
     +---+------+
     | m | n    |
     +---+------+
     | 1 |    1 |
     | 2 |    2 |
     | 3 |    1 |
     +---+------+
     3 rows in set (0.00 sec)

     slave> SELECT * FROM fc1;
     +---+------+
     | i | j    |
     +---+------+
     | 1 |    1 |
     | 2 |    2 |
     +---+------+
     2 rows in set (0.00 sec)

     slave> SELECT * FROM fc2;
     +---+------+
     | m | n    |
     +---+------+
     | 1 |    1 |
     | 2 |    2 |
     | 3 |    1 |
     +---+------+
     3 rows in set (0.00 sec)

Now suppose that you perform the following *Note `DELETE': delete.
statement on the master:

     master> DELETE FROM fc1 WHERE i=1;
     Query OK, 1 row affected (0.09 sec)

Due to the cascade, table `fc2' on the master now contains only 1 row:

     master> SELECT * FROM fc2;
     +---+---+
     | m | n |
     +---+---+
     | 2 | 2 |
     +---+---+
     1 row in set (0.00 sec)

However, the cascade does not propagate on the slave because on the
slave the *Note `DELETE': delete. for `fc1' deletes no rows from `fc2'.
The slave's copy of `fc2' still contains all of the rows that were
originally inserted:

     slave> SELECT * FROM fc2;
     +---+---+
     | m | n |
     +---+---+
     | 1 | 1 |
     | 3 | 1 |
     | 2 | 2 |
     +---+---+
     3 rows in set (0.00 sec)

This difference is due to the fact that the cascading deletes are
handled internally by the `InnoDB' storage engine, which means that
none of the changes are logged.


File: manual.info,  Node: innodb-data-log-reconfiguration,  Next: innodb-backup,  Prev: using-innodb-tables,  Up: innodb-storage-engine

14.2.5 Adding, Removing, or Resizing `InnoDB' Data and Log Files
----------------------------------------------------------------

This section describes what you can do when your `InnoDB' tablespace
runs out of room or when you want to change the size of the log files.

The easiest way to increase the size of the `InnoDB' tablespace is to
configure it from the beginning to be auto-extending. Specify the
`autoextend' attribute for the last data file in the tablespace
definition. Then `InnoDB' increases the size of that file automatically
in 8MB increments when it runs out of space. The increment size can be
changed by setting the value of the `innodb_autoextend_increment'
system variable, which is measured in MB.

Alternatively, you can increase the size of your tablespace by adding
another data file. To do this, you have to shut down the MySQL server,
change the tablespace configuration to add a new data file to the end of
`innodb_data_file_path', and start the server again.

If your last data file was defined with the keyword `autoextend', the
procedure for reconfiguring the tablespace must take into account the
size to which the last data file has grown. Obtain the size of the data
file, round it down to the closest multiple of 1024 x 1024 bytes (=
1MB), and specify the rounded size explicitly in
`innodb_data_file_path'. Then you can add another data file. Remember
that only the last data file in the `innodb_data_file_path' can be
specified as auto-extending.

As an example, assume that the tablespace has just one auto-extending
data file `ibdata1':

     innodb_data_home_dir =
     innodb_data_file_path = /ibdata/ibdata1:10M:autoextend

Suppose that this data file, over time, has grown to 988MB. Here is the
configuration line after modifying the original data file to not be
auto-extending and adding another auto-extending data file:

     innodb_data_home_dir =
     innodb_data_file_path = /ibdata/ibdata1:988M;/disk2/ibdata2:50M:autoextend

When you add a new file to the tablespace configuration, make sure that
it does not exist. `InnoDB' will create and initialize the file when
you restart the server.

Currently, you cannot remove a data file from the tablespace. To
decrease the size of your tablespace, use this procedure:

  1. Use *Note `mysqldump': mysqldump. to dump all your `InnoDB' tables.

  2. Stop the server.

  3. Remove all the existing tablespace files, including the `ibdata'
     and `ib_log' files. If you want to keep a backup copy of the
     information, then copy all the `ib*' files to another location
     before the removing the files in your MySQL installation.

  4. Remove any `.frm' files for `InnoDB' tables.

  5. Configure a new tablespace.

  6. Restart the server.

  7. Import the dump files.

If you want to change the number or the size of your `InnoDB' log
files, use the following instructions. The procedure to use depends on
the value of `innodb_fast_shutdown':

   * If `innodb_fast_shutdown' is not set to 2: Stop the MySQL server
     and make sure that it shuts down without errors (to ensure that
     there is no information for outstanding transactions in the log).
     Copy the old log files into a safe place in case something went
     wrong during the shutdown and you need them to recover the
     tablespace. Delete the old log files from the log file directory,
     edit `my.cnf' to change the log file configuration, and start the
     MySQL server again.  *Note `mysqld': mysqld. sees that no *Note
     `InnoDB': innodb-storage-engine. log files exist at startup and
     creates new ones.

   * If `innodb_fast_shutdown' is set to 2: Set `innodb_fast_shutdown'
     to 1:

          mysql> SET GLOBAL innodb_fast_shutdown = 1;

     Then follow the instructions in the previous item.


File: manual.info,  Node: innodb-backup,  Next: innodb-migration,  Prev: innodb-data-log-reconfiguration,  Up: innodb-storage-engine

14.2.6 Backing Up and Recovering an `InnoDB' Database
-----------------------------------------------------

* Menu:

* innodb-recovery::              The `InnoDB' Recovery Process
* forcing-innodb-recovery::      Forcing `InnoDB' Recovery
* innodb-checkpoints::           `InnoDB' Checkpoints

The key to safe database management is making regular backups.

`InnoDB Hot Backup' enables you to back up a running MySQL database,
including *Note `InnoDB': innodb-storage-engine. and *Note `MyISAM':
myisam-storage-engine. tables, with minimal disruption to operations
while producing a consistent snapshot of the database. When `InnoDB Hot
Backup' is copying *Note `InnoDB': innodb-storage-engine. tables, reads
and writes to both *Note `InnoDB': innodb-storage-engine. and *Note
`MyISAM': myisam-storage-engine. tables can continue. During the
copying of *Note `MyISAM': myisam-storage-engine. tables, reads (but
not writes) to those tables are permitted. In addition, `InnoDB Hot
Backup' supports creating compressed backup files, and performing
backups of subsets of *Note `InnoDB': innodb-storage-engine. tables. In
conjunction with MySQL's binary log, users can perform point-in-time
recovery.  `InnoDB Hot Backup' is commercially licensed by Innobase Oy.
For a more complete description of `InnoDB Hot Backup', see
`http://www.innodb.com/products/hot-backup/features/' or download the
documentation from `http://www.innodb.com/doc/hot_backup/manual.html'.
You can order trial, term, and perpetual licenses from Innobase at
`http://www.innodb.com/wp/products/hot-backup/order/'.

If you are able to shut down your MySQL server, you can make a binary
backup that consists of all files used by *Note `InnoDB':
innodb-storage-engine. to manage its tables. Use the following
procedure:

  1. Shut down the MySQL server and make sure that it stops without
     errors.

  2. Copy all *Note `InnoDB': innodb-storage-engine. data files
     (`ibdata' files and `.ibd' files) into a safe place.

  3. Copy all the `.frm' files for *Note `InnoDB':
     innodb-storage-engine. tables to a safe place.

  4. Copy all *Note `InnoDB': innodb-storage-engine. log files
     (`ib_logfile' files) to a safe place.

  5. Copy your `my.cnf' configuration file or files to a safe place.

In addition to making binary backups as just described, you should also
regularly make dumps of your tables with *Note `mysqldump': mysqldump.
The reason for this is that a binary file might be corrupted without
you noticing it. Dumped tables are stored into text files that are
human-readable, so spotting table corruption becomes easier. Also,
because the format is simpler, the chance for serious data corruption
is smaller.  *Note `mysqldump': mysqldump. also has a
`--single-transaction' option for making a consistent snapshot without
locking out other clients.  See *Note backup-policy::.

Replication works with *Note `InnoDB': innodb-storage-engine. tables,
so you can use MySQL replication capabilities to keep a copy of your
database at database sites requiring high availability.

To be able to recover your *Note `InnoDB': innodb-storage-engine.
database to the present from the time at which the binary backup was
made, you must run your MySQL server with binary logging turned on. To
achieve point-in-time recovery after restoring a backup, you can apply
changes from the binary log that occurred after the backup was made. See
*Note point-in-time-recovery::.

To recover from a crash of your MySQL server, the only requirement is
to restart it. *Note `InnoDB': innodb-storage-engine.  automatically
checks the logs and performs a roll-forward of the database to the
present. *Note `InnoDB': innodb-storage-engine.  automatically rolls
back uncommitted transactions that were present at the time of the
crash. During recovery, *Note `mysqld': mysqld. displays output
something like this:

     InnoDB: Database was not shut down normally.
     InnoDB: Starting recovery from log files...
     InnoDB: Starting log scan based on checkpoint at
     InnoDB: log sequence number 0 13674004
     InnoDB: Doing recovery: scanned up to log sequence number 0 13739520
     InnoDB: Doing recovery: scanned up to log sequence number 0 13805056
     InnoDB: Doing recovery: scanned up to log sequence number 0 13870592
     InnoDB: Doing recovery: scanned up to log sequence number 0 13936128
     ...
     InnoDB: Doing recovery: scanned up to log sequence number 0 20555264
     InnoDB: Doing recovery: scanned up to log sequence number 0 20620800
     InnoDB: Doing recovery: scanned up to log sequence number 0 20664692
     InnoDB: 1 uncommitted transaction(s) which must be rolled back
     InnoDB: Starting rollback of uncommitted transactions
     InnoDB: Rolling back trx no 16745
     InnoDB: Rolling back of trx no 16745 completed
     InnoDB: Rollback of uncommitted transactions completed
     InnoDB: Starting an apply batch of log records to the database...
     InnoDB: Apply batch completed
     InnoDB: Started
     mysqld: ready for connections

If your database becomes corrupted or disk failure occurs, you must
perform the recovery using a backup. In the case of corruption, you
should first find a backup that is not corrupted.  After restoring the
base backup, do a point-in-time recovery from the binary log files
using *Note `mysqlbinlog': mysqlbinlog. and *Note `mysql': mysql. to
restore the changes that occurred after the backup was made.

In some cases of database corruption it is enough just to dump, drop,
and re-create one or a few corrupt tables. You can use the *Note `CHECK
TABLE': check-table. SQL statement to check whether a table is corrupt,
although *Note `CHECK TABLE': check-table. naturally cannot detect
every possible kind of corruption. You can use the Tablespace Monitor
to check the integrity of the file space management inside the
tablespace files.

In some cases, apparent database page corruption is actually due to the
operating system corrupting its own file cache, and the data on disk
may be okay. It is best first to try restarting your computer. Doing so
may eliminate errors that appeared to be database page corruption.


File: manual.info,  Node: innodb-recovery,  Next: forcing-innodb-recovery,  Prev: innodb-backup,  Up: innodb-backup

14.2.6.1 The `InnoDB' Recovery Process
......................................

`InnoDB' crash recovery consists of several steps. The first step, redo
log application, is performed during the initialization, before
accepting any connections. If all changes were flushed from the buffer
pool to the tablespaces (`ibdata*' and `*.ibd' files) at the time of
the shutdown or crash, the redo log application can be skipped. If the
redo log files are missing at startup, `InnoDB' skips the redo log
application.

The remaining steps after redo log application do not depend on the
redo log (other than for logging the writes) and are performed in
parallel with normal processing. These include:

   * Rolling back incomplete transactions: Any transactions that were
     active at the time of crash or fast shutdown.

   * Insert buffer merge: Applying changes from the insert buffer tree
     (from the shared tablespace) to leaf pages of secondary indexes as
     the index pages are read to the buffer pool.

   * Purge: Deleting delete-marked records that are no longer visible
     for any active transaction.

Of these, only rollback of incomplete transactions is special to crash
recovery. The insert buffer merge and the purge are performed during
normal processing.


File: manual.info,  Node: forcing-innodb-recovery,  Next: innodb-checkpoints,  Prev: innodb-recovery,  Up: innodb-backup

14.2.6.2 Forcing `InnoDB' Recovery
..................................

If there is database page corruption, you may want to dump your tables
from the database with *Note `SELECT ... INTO OUTFILE': select-into.
Usually, most of the data obtained in this way is intact. However, it
is possible that the corruption might cause `SELECT * FROM TBL_NAME'
statements or `InnoDB' background operations to crash or assert, or
even cause `InnoDB' roll-forward recovery to crash. In such cases, you
can use the `innodb_force_recovery' option to force the `InnoDB'
storage engine to start up while preventing background operations from
running, so that you are able to dump your tables. For example, you can
add the following line to the `[mysqld]' section of your option file
before restarting the server:

     [mysqld]
     innodb_force_recovery = 4

`innodb_force_recovery' is 0 by default (normal startup without forced
recovery) The permissible nonzero values for `innodb_force_recovery'
follow. A larger number includes all precautions of smaller numbers. If
you are able to dump your tables with an option value of at most 4,
then you are relatively safe that only some data on corrupt individual
pages is lost. A value of 6 is more drastic because database pages are
left in an obsolete state, which in turn may introduce more corruption
into B-trees and other database structures.

   * `1' (`SRV_FORCE_IGNORE_CORRUPT')

     Let the server run even if it detects a corrupt page. Try to make
     `SELECT * FROM TBL_NAME' jump over corrupt index records and
     pages, which helps in dumping tables.

   * `2' (`SRV_FORCE_NO_BACKGROUND')

     Prevent the main thread from running. If a crash would occur
     during the purge operation, this recovery value prevents it.

   * `3' (`SRV_FORCE_NO_TRX_UNDO')

     Do not run transaction rollbacks after recovery.

   * `4' (`SRV_FORCE_NO_IBUF_MERGE')

     Prevent insert buffer merge operations. If they would cause a
     crash, do not do them. Do not calculate table statistics.

   * `5' (`SRV_FORCE_NO_UNDO_LOG_SCAN')

     Do not look at undo logs when starting the database: `InnoDB'
     treats even incomplete transactions as committed.

   * `6' (`SRV_FORCE_NO_LOG_REDO')

     Do not do the log roll-forward in connection with recovery.

_The database must not otherwise be used with any nonzero value of
`innodb_force_recovery'_.  As a safety measure, `InnoDB' prevents users
from performing *Note `INSERT': insert, *Note `UPDATE': update, or
*Note `DELETE': delete. operations when `innodb_force_recovery' is
greater than 0.

You can *Note `SELECT': select. from tables to dump them, or `DROP' or
`CREATE' tables even if forced recovery is used. If you know that a
given table is causing a crash on rollback, you can drop it. You can
also use this to stop a runaway rollback caused by a failing mass
import or *Note `ALTER TABLE': alter-table. You can kill the *Note
`mysqld': mysqld. process and set `innodb_force_recovery' to `3' to
bring the database up without the rollback, then `DROP' the table that
is causing the runaway rollback.


File: manual.info,  Node: innodb-checkpoints,  Prev: forcing-innodb-recovery,  Up: innodb-backup

14.2.6.3 `InnoDB' Checkpoints
.............................

`InnoDB' implements a checkpoint mechanism known as `fuzzy'
checkpointing.  `InnoDB' flushes modified database pages from the
buffer pool in small batches. There is no need to flush the buffer pool
in one single batch, which would in practice stop processing of user
SQL statements during the checkpointing process.

During crash recovery, `InnoDB' looks for a checkpoint label written to
the log files. It knows that all modifications to the database before
the label are present in the disk image of the database. Then `InnoDB'
scans the log files forward from the checkpoint, applying the logged
modifications to the database.

`InnoDB' writes to its log files on a rotating basis. It also writes
checkpoint information to the first log file at each checkpoint. All
committed modifications that make the database pages in the buffer pool
different from the images on disk must be available in the log files in
case `InnoDB' has to do a recovery. This means that when `InnoDB'
starts to reuse a log file, it has to make sure that the database page
images on disk contain the modifications logged in the log file that
`InnoDB' is going to reuse. In other words, `InnoDB' must create a
checkpoint and this often involves flushing of modified database pages
to disk.

The preceding description explains why making your log files very large
may reduce disk I/O in checkpointing. It often makes sense to set the
total size of the log files as large as the buffer pool or even larger.
The disadvantage of using large log files is that crash recovery can
take longer because there is more logged information to apply to the
database.


File: manual.info,  Node: innodb-migration,  Next: innodb-transaction-model,  Prev: innodb-backup,  Up: innodb-storage-engine

14.2.7 Moving an `InnoDB' Database to Another Machine
-----------------------------------------------------

On Windows, `InnoDB' always stores database and table names internally
in lowercase. To move databases in a binary format from Unix to Windows
or from Windows to Unix, create all databases and tables using
lowercase names. A convenient way to accomplish this is to add the
following line to the `[mysqld]' section of your `my.cnf' or `my.ini'
file before creating any databases or tables:

     [mysqld]
     lower_case_table_names=1

Like `MyISAM' data files, `InnoDB' data and log files are
binary-compatible on all platforms having the same floating-point
number format. You can move an `InnoDB' database simply by copying all
the relevant files listed in *Note innodb-backup::.  If the
floating-point formats differ but you have not used *Note `FLOAT':
numeric-types. or *Note `DOUBLE': numeric-types. data types in your
tables, then the procedure is the same: simply copy the relevant files.
If you use *Note `mysqldump': mysqldump. to dump your tables on one
machine and then import the dump files on the other machine, it does
not matter whether the formats differ or your tables contain
floating-point data.

One way to increase performance is to switch off autocommit mode when
importing data, assuming that the tablespace has enough space for the
big rollback segment that the import transactions generate. Do the
commit only after importing a whole table or a segment of a table.


File: manual.info,  Node: innodb-transaction-model,  Next: innodb-multi-versioning,  Prev: innodb-migration,  Up: innodb-storage-engine

14.2.8 The `InnoDB' Transaction Model and Locking
-------------------------------------------------

* Menu:

* innodb-lock-modes::            `InnoDB' Lock Modes
* innodb-consistent-read::       Consistent Nonlocking Reads
* innodb-locking-reads::         `SELECT ... FOR UPDATE' and `SELECT ... LOCK IN SHARE MODE' Locking Reads
* innodb-record-level-locks::    `InnoDB' Record, Gap, and Next-Key Locks
* innodb-next-key-locking::      Avoiding the Phantom Problem Using Next-Key Locking
* innodb-locks-set::             Locks Set by Different SQL Statements in `InnoDB'
* innodb-implicit-commit::       Implicit Transaction Commit and Rollback
* innodb-deadlock-detection::    Deadlock Detection and Rollback
* innodb-deadlocks::             How to Cope with Deadlocks

In the `InnoDB' transaction model, the goal is to combine the best
properties of a multi-versioning database with traditional two-phase
locking. `InnoDB' does locking on the row level and runs queries as
nonlocking consistent reads by default, in the style of Oracle. The
lock table in `InnoDB' is stored so space-efficiently that lock
escalation is not needed: Typically, several users are permitted to
lock every row in `InnoDB' tables, or any random subset of the rows,
without causing `InnoDB' memory exhaustion.

In `InnoDB', all user activity occurs inside a transaction. If
autocommit mode is enabled, each SQL statement forms a single
transaction on its own. By default, MySQL starts the session for each
new connection with autocommit enabled, so MySQL does a commit after
each SQL statement if that statement did not return an error. If a
statement returns an error, the commit or rollback behavior depends on
the error. See *Note innodb-error-handling::.

A session that has autocommit enabled can perform a multiple-statement
transaction by starting it with an explicit *Note `START TRANSACTION':
commit. or *Note `BEGIN': commit. statement and ending it with a *Note
`COMMIT': commit. or *Note `ROLLBACK': commit.  statement. See *Note
commit::.

If autocommit mode is disabled within a session with `SET autocommit =
0', the session always has a transaction open. A *Note `COMMIT':
commit. or *Note `ROLLBACK': commit.  statement ends the current
transaction and a new one starts.

A *Note `COMMIT': commit. means that the changes made in the current
transaction are made permanent and become visible to other sessions. A
*Note `ROLLBACK': commit.  statement, on the other hand, cancels all
modifications made by the current transaction. Both *Note `COMMIT':
commit. and *Note `ROLLBACK': commit. release all `InnoDB' locks that
were set during the current transaction.

In terms of the SQL:1992 transaction isolation levels, the default
`InnoDB' level is `REPEATABLE READ'.  `InnoDB' offers all four
transaction isolation levels described by the SQL standard: `READ
UNCOMMITTED', `READ COMMITTED', `REPEATABLE READ', and `SERIALIZABLE'.

A user can change the isolation level for a single session or for all
subsequent connections with the *Note `SET TRANSACTION':
set-transaction. statement. To set the server's default isolation level
for all connections, use the `--transaction-isolation' option on the
command line or in an option file. For detailed information about
isolation levels and level-setting syntax, see *Note set-transaction::.

In row-level locking, `InnoDB' normally uses next-key locking. That
means that besides index records, `InnoDB' can also lock the `gap'
preceding an index record to block insertions by other sessions in the
gap immediately before the index record. A next-key lock refers to a
lock that locks an index record and the gap before it.  A gap lock
refers to a lock that locks only the gap before some index record.

For more information about row-level locking, and the circumstances
under which gap locking is disabled, see *Note
innodb-record-level-locks::.


File: manual.info,  Node: innodb-lock-modes,  Next: innodb-consistent-read,  Prev: innodb-transaction-model,  Up: innodb-transaction-model

14.2.8.1 `InnoDB' Lock Modes
............................

`InnoDB' implements standard row-level locking where there are two
types of locks:

   * A shared (S) lock permits a transaction to read a row.

   * An exclusive (X) lock permits a transaction to update or delete a
     row.

If transaction `T1' holds a shared (S) lock on row `r', then requests
from some distinct transaction `T2' for a lock on row `r' are handled
as follows:

   * A request by `T2' for an S lock can be granted immediately. As a
     result, both `T1' and `T2' hold an S lock on `r'.

   * A request by `T2' for an X lock cannot be granted immediately.

If a transaction `T1' holds an exclusive (X) lock on row `r', a request
from some distinct transaction `T2' for a lock of either type on `r'
cannot be granted immediately. Instead, transaction `T2' has to wait
for transaction `T1' to release its lock on row `r'.

Additionally, `InnoDB' supports _multiple granularity locking_ which
permits coexistence of record locks and locks on entire tables. To make
locking at multiple granularity levels practical, additional types of
locks called _intention locks_ are used. Intention locks are table
locks in `InnoDB'. The idea behind intention locks is for a transaction
to indicate which type of lock (shared or exclusive) it will require
later for a row in that table. There are two types of intention locks
used in `InnoDB' (assume that transaction `T' has requested a lock of
the indicated type on table `t'):

   * Intention shared (IS): Transaction `T' intends to set S locks on
     individual rows in table `t'.

   * Intention exclusive (IX): Transaction `T' intends to set X locks
     on those rows.

For example, *Note `SELECT ... LOCK IN SHARE MODE': select. sets an IS
lock and *Note `SELECT ... FOR UPDATE': select. sets an IX lock.

The intention locking protocol is as follows:

   * Before a transaction can acquire an S lock on a row in table `t',
     it must first acquire an IS or stronger lock on `t'.

   * Before a transaction can acquire an X lock on a row, it must first
     acquire an IX lock on `t'.

These rules can be conveniently summarized by means of the following
_lock type compatibility matrix_.

               X              IX             S              IS
X              Conflict       Conflict       Conflict       Conflict
IX             Conflict       Compatible     Conflict       Compatible
S              Conflict       Conflict       Compatible     Compatible
IS             Conflict       Compatible     Compatible     Compatible

A lock is granted to a requesting transaction if it is compatible with
existing locks, but not if it conflicts with existing locks. A
transaction waits until the conflicting existing lock is released. If a
lock request conflicts with an existing lock and cannot be granted
because it would cause deadlock, an error occurs.

Thus, intention locks do not block anything except full table requests
(for example, `LOCK TABLES ...  WRITE'). The main purpose of IX and IS
locks is to show that someone is locking a row, or going to lock a row
in the table.

The following example illustrates how an error can occur when a lock
request would cause a deadlock. The example involves two clients, A and
B.

First, client A creates a table containing one row, and then begins a
transaction. Within the transaction, A obtains an S lock on the row by
selecting it in share mode:


     mysql> CREATE TABLE t (i INT) ENGINE = InnoDB;
     Query OK, 0 rows affected (1.07 sec)

     mysql> INSERT INTO t (i) VALUES(1);
     Query OK, 1 row affected (0.09 sec)

     mysql> START TRANSACTION;
     Query OK, 0 rows affected (0.00 sec)

     mysql> SELECT * FROM t WHERE i = 1 LOCK IN SHARE MODE;
     +------+
     | i    |
     +------+
     |    1 |
     +------+
     1 row in set (0.10 sec)

Next, client B begins a transaction and attempts to delete the row from
the table:

     mysql> START TRANSACTION;
     Query OK, 0 rows affected (0.00 sec)

     mysql> DELETE FROM t WHERE i = 1;

The delete operation requires an X lock. The lock cannot be granted
because it is incompatible with the S lock that client A holds, so the
request goes on the queue of lock requests for the row and client B
blocks.

Finally, client A also attempts to delete the row from the table:

     mysql> DELETE FROM t WHERE i = 1;
     ERROR 1213 (40001): Deadlock found when trying to get lock;
     try restarting transaction

Deadlock occurs here because client A needs an X lock to delete the
row. However, that lock request cannot be granted because client B
already has a request for an X lock and is waiting for client A to
release its S lock. Nor can the S lock held by A be upgraded to an X
lock because of the prior request by B for an X lock. As a result,
`InnoDB' generates an error for client A and releases its locks. At
that point, the lock request for client B can be granted and B deletes
the row from the table.


File: manual.info,  Node: innodb-consistent-read,  Next: innodb-locking-reads,  Prev: innodb-lock-modes,  Up: innodb-transaction-model

14.2.8.2 Consistent Nonlocking Reads
....................................

A consistent read means that `InnoDB' uses multi-versioning to present
to a query a snapshot of the database at a point in time. The query
sees the changes made by transactions that committed before that point
of time, and no changes made by later or uncommitted transactions. The
exception to this rule is that the query sees the changes made by
earlier statements within the same transaction. This exception causes
the following anomaly: If you update some rows in a table, a *Note
`SELECT': select. will see the latest version of the updated rows, but
it might also see older versions of any rows. If other sessions
simultaneously update the same table, the anomaly means that you may
see the table in a state that never existed in the database.

If the transaction isolation level is `REPEATABLE READ' (the default
level), all consistent reads within the same transaction read the
snapshot established by the first such read in that transaction. You
can get a fresher snapshot for your queries by committing the current
transaction and after that issuing new queries.

With `READ COMMITTED' isolation level, each consistent read within a
transaction sets and reads its own fresh snapshot.

Consistent read is the default mode in which `InnoDB' processes *Note
`SELECT': select. statements in `READ COMMITTED' and `REPEATABLE READ'
isolation levels. A consistent read does not set any locks on the tables
it accesses, and therefore other sessions are free to modify those
tables at the same time a consistent read is being performed on the
table.

Suppose that you are running in the default `REPEATABLE READ' isolation
level. When you issue a consistent read (that is, an ordinary *Note
`SELECT': select. statement), `InnoDB' gives your transaction a
timepoint according to which your query sees the database. If another
transaction deletes a row and commits after your timepoint was
assigned, you do not see the row as having been deleted. Inserts and
updates are treated similarly.

You can advance your timepoint by committing your transaction and then
doing another *Note `SELECT': select.

This is called _multi-versioned concurrency control_.

In the following example, session A sees the row inserted by B only
when B has committed the insert and A has committed as well, so that
the timepoint is advanced past the commit of B.

                  Session A              Session B

                SET autocommit=0;      SET autocommit=0;
     time
     |          SELECT * FROM t;
     |          empty set
     |                                 INSERT INTO t VALUES (1, 2);
     |
     v          SELECT * FROM t;
                empty set
                                       COMMIT;

                SELECT * FROM t;
                empty set

                COMMIT;

                SELECT * FROM t;
                ---------------------
                |    1    |    2    |
                ---------------------
                1 row in set

If you want to see the `freshest' state of the database, you should use
either the `READ COMMITTED' isolation level or a locking read:

     SELECT * FROM t LOCK IN SHARE MODE;

With `READ COMMITTED' isolation level, each consistent read within a
transaction sets and reads its own fresh snapshot. With `LOCK IN SHARE
MODE', a locking read occurs instead: A `SELECT' blocks until the
transaction containing the freshest rows ends (see *Note
innodb-locking-reads::).

Consistent read does not work over *Note `DROP TABLE': drop-table. or
over *Note `ALTER TABLE': alter-table.:

   * Consistent read does not work over *Note `DROP TABLE': drop-table.
     because MySQL cannot use a table that has been dropped and
     `InnoDB' destroys the table.

   * Consistent read does not work over *Note `ALTER TABLE':
     alter-table. because *Note `ALTER TABLE': alter-table. works by
     making a temporary copy of the original table and deleting the
     original table when the temporary copy is built. When you reissue
     a consistent read within a transaction, rows in the new table are
     not visible because those rows did not exist when the
     transaction's snapshot was taken.

`InnoDB' uses a consistent read for select in clauses like *Note
`INSERT INTO ... SELECT': insert, *Note `UPDATE ... (SELECT)': update,
and *Note `CREATE TABLE ... SELECT': create-table. that do not specify
`FOR UPDATE' or `LOCK IN SHARE MODE' if the
`innodb_locks_unsafe_for_binlog' option is set and the isolation level
of the transaction is not set to `SERIALIZABLE'. Thus, no locks are set
on rows read from the selected table. Otherwise, `InnoDB' uses stronger
locks and the *Note `SELECT': select. part acts like `READ COMMITTED',
where each consistent read, even within the same transaction, sets and
reads its own fresh snapshot.


File: manual.info,  Node: innodb-locking-reads,  Next: innodb-record-level-locks,  Prev: innodb-consistent-read,  Up: innodb-transaction-model

14.2.8.3 `SELECT ... FOR UPDATE' and `SELECT ... LOCK IN SHARE MODE' Locking Reads
..................................................................................

In some circumstances, a consistent (nonlocking) read is not convenient
and a locking read is required instead.  `InnoDB' supports two types of
locking reads:

   * *Note `SELECT ... LOCK IN SHARE MODE': select. sets a shared mode
     lock on the rows read. A shared mode lock enables other sessions
     to read the rows but not to modify them. The rows read are the
     latest available, so if they belong to another transaction that has
     not yet committed, the read blocks until that transaction ends.

   * For index records the search encounters, *Note `SELECT ... FOR
     UPDATE': select. blocks other sessions from doing *Note `SELECT
     ... LOCK IN SHARE MODE': select. or from reading in certain
     transaction isolation levels. Consistent reads will ignore any
     locks set on the records that exist in the read view. (Old
     versions of a record cannot be locked; they will be reconstructed
     by applying undo logs on an in-memory copy of the record.)

Locks set by `LOCK IN SHARE MODE' and `FOR UPDATE' reads are released
when the transaction is committed or rolled back.

As an example of a situation in which a locking read is useful, suppose
that you want to insert a new row into a table `child', and make sure
that the child row has a parent row in table `parent'. The following
discussion describes how to implement referential integrity in
application code.

Suppose that you use a consistent read to read the table `parent' and
indeed see the parent row of the to-be-inserted child row in the table.
Can you safely insert the child row to table `child'? No, because it is
possible for some other session to delete the parent row from the table
`parent' in the meantime without you being aware of it.

The solution is to perform the *Note `SELECT': select. in a locking
mode using `LOCK IN SHARE MODE':

     SELECT * FROM parent WHERE NAME = 'Jones' LOCK IN SHARE MODE;

A read performed with `LOCK IN SHARE MODE' reads the latest available
data and sets a shared mode lock on the rows read. A shared mode lock
prevents others from updating or deleting the row read. Also, if the
latest data belongs to a yet uncommitted transaction of another
session, we wait until that transaction ends. After we see that the
`LOCK IN SHARE MODE' query returns the parent `'Jones'', we can safely
add the child record to the `child' table and commit our transaction.

Let us look at another example: We have an integer counter field in a
table `child_codes' that we use to assign a unique identifier to each
child added to table `child'. It is not a good idea to use either
consistent read or a shared mode read to read the present value of the
counter because two users of the database may then see the same value
for the counter, and a duplicate-key error occurs if two users attempt
to add children with the same identifier to the table.

Here, `LOCK IN SHARE MODE' is not a good solution because if two users
read the counter at the same time, at least one of them ends up in
deadlock when it attempts to update the counter.

In this case, there are two good ways to implement reading and
incrementing the counter:

   * First update the counter by incrementing it by 1, and then read it.

   * First perform a locking read of the counter using `FOR UPDATE',
     and then increment the counter.

The latter approach can be implemented as follows:

     SELECT counter_field FROM child_codes FOR UPDATE;
     UPDATE child_codes SET counter_field = counter_field + 1;

A *Note `SELECT ... FOR UPDATE': select. reads the latest available
data, setting exclusive locks on each row it reads. Thus, it sets the
same locks a searched SQL *Note `UPDATE': update. would set on the rows.

The preceding description is merely an example of how *Note `SELECT ...
FOR UPDATE': select. works. In MySQL, the specific task of generating a
unique identifier actually can be accomplished using only a single
access to the table:

     UPDATE child_codes SET counter_field = LAST_INSERT_ID(counter_field + 1);
     SELECT LAST_INSERT_ID();

The *Note `SELECT': select. statement merely retrieves the identifier
information (specific to the current connection). It does not access
any table.

*Note*:

Locking of rows for update using `SELECT FOR UPDATE' only applies when
autocommit is disabled (either by beginning transaction with *Note
`START TRANSACTION': commit. or by setting `autocommit' to 0. If
autocommit is enabled, the rows matching the specification are not
locked.


File: manual.info,  Node: innodb-record-level-locks,  Next: innodb-next-key-locking,  Prev: innodb-locking-reads,  Up: innodb-transaction-model

14.2.8.4 `InnoDB' Record, Gap, and Next-Key Locks
.................................................

`InnoDB' has several types of record-level locks:

   * Record lock: This is a lock on an index record.

   * Gap lock: This is a lock on a gap between index records, or a lock
     on the gap before the first or after the last index record.

   * Next-key lock: This is a combination of a record lock on the index
     record and a gap lock on the gap before the index record.

Record locks always lock index records, even if a table is defined with
no indexes. For such cases, `InnoDB' creates a hidden clustered index
and uses this index for record locking. See *Note innodb-index-types::.

By default, `InnoDB' operates in `REPEATABLE READ' transaction
isolation level and with the `innodb_locks_unsafe_for_binlog' system
variable disabled. In this case, `InnoDB' uses next-key locks for
searches and index scans, which prevents phantom rows (see *Note
innodb-next-key-locking::).

Next-key locking combines index-row locking with gap locking.  `InnoDB'
performs row-level locking in such a way that when it searches or scans
a table index, it sets shared or exclusive locks on the index records
it encounters. Thus, the row-level locks are actually index-record
locks. In addition, a next-key lock on an index record also affects the
`gap' before that index record. That is, a next-key lock is an
index-record lock plus a gap lock on the gap preceding the index
record. If one session has a shared or exclusive lock on record `R' in
an index, another session cannot insert a new index record in the gap
immediately before `R' in the index order.

Suppose that an index contains the values 10, 11, 13, and 20.  The
possible next-key locks for this index cover the following intervals,
where `(' or `)' denote exclusion of the interval endpoint and `[' or
`]' denote inclusion of the endpoint:

     (negative infinity, 10]
     (10, 11]
     (11, 13]
     (13, 20]
     (20, positive infinity)

For the last interval, the next-key lock locks the gap above the
largest value in the index and the `supremum' pseudo-record having a
value higher than any value actually in the index. The supremum is not
a real index record, so, in effect, this next-key lock locks only the
gap following the largest index value.

The preceding example shows that a gap might span a single index value,
multiple index values, or even be empty.

Gap locking is not needed for statements that lock rows using a unique
index to search for a unique row. (This does not include the case that
the search condition includes only some columns of a multiple-column
unique index; in that case, gap locking does occur.) For example, if
the `id' column has a unique index, the following statement uses only
an index-record lock for the row having `id' value 100 and it does not
matter whether other sessions insert rows in the preceding gap:

     SELECT * FROM child WHERE id = 100;

If `id' is not indexed or has a nonunique index, the statement does
lock the preceding gap.

A type of gap lock called an insertion intention gap lock is set by
*Note `INSERT': insert. operations prior to row insertion. This lock
signals the intent to insert in such a way that multiple transactions
inserting into the same index gap need not wait for each other if they
are not inserting at the same position within the gap. Suppose that
there are index records with values of 4 and 7. Separate transactions
that attempt to insert values of 5 and 6 each lock the gap between 4
and 7 with insert intention locks prior to obtaining the exclusive lock
on the inserted row, but do not block each other because the rows are
nonconflicting.

Gap locking can be disabled explicitly. This occurs if you change the
transaction isolation level to `READ COMMITTED' or enable the
`innodb_locks_unsafe_for_binlog' system variable. Under these
circumstances, gap locking is disabled for searches and index scans and
is used only for foreign-key constraint checking and duplicate-key
checking.

There is also another effect of using the `READ COMMITTED' isolation
level or enabling `innodb_locks_unsafe_for_binlog': Record locks for
nonmatching rows are released after MySQL has evaluated the `WHERE'
condition.


File: manual.info,  Node: innodb-next-key-locking,  Next: innodb-locks-set,  Prev: innodb-record-level-locks,  Up: innodb-transaction-model

14.2.8.5 Avoiding the Phantom Problem Using Next-Key Locking
............................................................

The so-called _phantom_ problem occurs within a transaction when the
same query produces different sets of rows at different times. For
example, if a *Note `SELECT': select. is executed twice, but returns a
row the second time that was not returned the first time, the row is a
`phantom' row.

Suppose that there is an index on the `id' column of the `child' table
and that you want to read and lock all rows from the table having an
identifier value larger than 100, with the intention of updating some
column in the selected rows later:

     SELECT * FROM child WHERE id > 100 FOR UPDATE;

The query scans the index starting from the first record where `id' is
bigger than 100. Let the table contain rows having `id' values of 90
and 102. If the locks set on the index records in the scanned range do
not lock out inserts made in the gaps (in this case, the gap between 90
and 102), another session can insert a new row into the table with an
`id' of 101. If you were to execute the same *Note `SELECT': select.
within the same transaction, you would see a new row with an `id' of
101 (a `phantom') in the result set returned by the query. If we regard
a set of rows as a data item, the new phantom child would violate the
isolation principle of transactions that a transaction should be able to
run so that the data it has read does not change during the transaction.

To prevent phantoms, `InnoDB' uses an algorithm called _next-key
locking_ that combines index-row locking with gap locking. `InnoDB'
performs row-level locking in such a way that when it searches or scans
a table index, it sets shared or exclusive locks on the index records
it encounters. Thus, the row-level locks are actually index-record
locks. In addition, a next-key lock on an index record also affects the
`gap' before that index record. That is, a next-key lock is an
index-record lock plus a gap lock on the gap preceding the index
record. If one session has a shared or exclusive lock on record `R' in
an index, another session cannot insert a new index record in the gap
immediately before `R' in the index order.

When `InnoDB' scans an index, it can also lock the gap after the last
record in the index. Just that happens in the preceding example: To
prevent any insert into the table where `id' would be bigger than 100,
the locks set by `InnoDB' include a lock on the gap following `id'
value 102.

You can use next-key locking to implement a uniqueness check in your
application: If you read your data in share mode and do not see a
duplicate for a row you are going to insert, then you can safely insert
your row and know that the next-key lock set on the successor of your
row during the read prevents anyone meanwhile inserting a duplicate for
your row. Thus, the next-key locking enables you to `lock' the
nonexistence of something in your table.

Gap locking can be disabled as discussed in *Note
innodb-record-level-locks::. This may cause phantom problems because
other sessions can insert new rows into the gaps when gap locking is
disabled.


File: manual.info,  Node: innodb-locks-set,  Next: innodb-implicit-commit,  Prev: innodb-next-key-locking,  Up: innodb-transaction-model

14.2.8.6 Locks Set by Different SQL Statements in `InnoDB'
..........................................................

A locking read, an *Note `UPDATE': update, or a *Note `DELETE': delete.
generally set record locks on every index record that is scanned in the
processing of the SQL statement. It does not matter whether there are
`WHERE' conditions in the statement that would exclude the row.
`InnoDB' does not remember the exact `WHERE' condition, but only knows
which index ranges were scanned. The locks are normally next-key locks
that also block inserts into the `gap' immediately before the record.
However, gap locking can be disabled explicitly, which causes next-key
locking not to be used. For more information, see *Note
innodb-record-level-locks::. The transaction isolation level also can
affect which locks are set; see *Note set-transaction::.

If a secondary index is used in a search and index record locks to be
set are exclusive, `InnoDB' also retrieves the corresponding clustered
index records and sets locks on them.

Differences between shared and exclusive locks are described in *Note
innodb-lock-modes::.

If you have no indexes suitable for your statement and MySQL must scan
the entire table to process the statement, every row of the table
becomes locked, which in turn blocks all inserts by other users to the
table. It is important to create good indexes so that your queries do
not unnecessarily scan many rows.

For *Note `SELECT ... FOR UPDATE': select. or *Note `SELECT ... LOCK IN
SHARE MODE': select, locks are acquired for scanned rows, and expected
to be released for rows that do not qualify for inclusion in the result
set (for example, if they do not meet the criteria given in the `WHERE'
clause).  However, in some cases, rows might not be unlocked immediately
because the relationship between a result row and its original source
is lost during query execution. For example, in a *Note `UNION': union,
scanned (and locked) rows from a table might be inserted into a
temporary table before evaluation whether they qualify for the result
set. In this circumstance, the relationship of the rows in the temporary
table to the rows in the original table is lost and the latter rows are
not unlocked until the end of query execution.

`InnoDB' sets specific types of locks as follows.

   * *Note `SELECT ... FROM': select. is a consistent read, reading a
     snapshot of the database and setting no locks unless the
     transaction isolation level is set to `SERIALIZABLE'. For
     `SERIALIZABLE' level, the search sets shared next-key locks on the
     index records it encounters.

   * *Note `SELECT ... FROM ... LOCK IN SHARE MODE': select. sets
     shared next-key locks on all index records the search encounters.

   * For index records the search encounters, *Note `SELECT ... FROM
     ... FOR UPDATE': select. blocks other sessions from doing *Note
     `SELECT ... FROM ... LOCK IN SHARE MODE': select. or from reading
     in certain transaction isolation levels. Consistent reads will
     ignore any locks set on the records that exist in the read view.

   * *Note `UPDATE ... WHERE ...': update. sets an exclusive next-key
     lock on every record the search encounters.

   * *Note `DELETE FROM ... WHERE ...': delete. sets an exclusive
     next-key lock on every record the search encounters.

   * *Note `INSERT': insert. sets an exclusive lock on the inserted
     row. This lock is an index-record lock, not a next-key lock (that
     is, there is no gap lock) and does not prevent other sessions from
     inserting into the gap before the inserted row.

     Prior to inserting the row, a type of gap lock called an insertion
     intention gap lock is set. This lock signals the intent to insert
     in such a way that multiple transactions inserting into the same
     index gap need not wait for each other if they are not inserting
     at the same position within the gap. Suppose that there are index
     records with values of 4 and 7. Separate transactions that attempt
     to insert values of 5 and 6 each lock the gap between 4 and 7 with
     insert intention locks prior to obtaining the exclusive lock on the
     inserted row, but do not block each other because the rows are
     nonconflicting.

     If a duplicate-key error occurs, a shared lock on the duplicate
     index record is set. This use of a shared lock can result in
     deadlock should there be multiple sessions trying to insert the
     same row if another session already has an exclusive lock. This
     can occur if another session deletes the row. Suppose that an
     `InnoDB' table `t1' has the following structure:

          CREATE TABLE t1 (i INT, PRIMARY KEY (i)) ENGINE = InnoDB;

     Now suppose that three sessions perform the following operations
     in order:

     Session 1:

          START TRANSACTION;
          INSERT INTO t1 VALUES(1);

     Session 2:

          START TRANSACTION;
          INSERT INTO t1 VALUES(1);

     Session 3:

          START TRANSACTION;
          INSERT INTO t1 VALUES(1);

     Session 1:

          ROLLBACK;

     The first operation by session 1 acquires an exclusive lock for
     the row. The operations by sessions 2 and 3 both result in a
     duplicate-key error and they both request a shared lock for the
     row. When session 1 rolls back, it releases its exclusive lock on
     the row and the queued shared lock requests for sessions 2 and 3
     are granted. At this point, sessions 2 and 3 deadlock: Neither can
     acquire an exclusive lock for the row because of the shared lock
     held by the other.

     A similar situation occurs if the table already contains a row
     with key value 1 and three sessions perform the following
     operations in order:

     Session 1:

          START TRANSACTION;
          DELETE FROM t1 WHERE i = 1;

     Session 2:

          START TRANSACTION;
          INSERT INTO t1 VALUES(1);

     Session 3:

          START TRANSACTION;
          INSERT INTO t1 VALUES(1);

     Session 1:

          COMMIT;

     The first operation by session 1 acquires an exclusive lock for
     the row. The operations by sessions 2 and 3 both result in a
     duplicate-key error and they both request a shared lock for the
     row. When session 1 commits, it releases its exclusive lock on the
     row and the queued shared lock requests for sessions 2 and 3 are
     granted. At this point, sessions 2 and 3 deadlock: Neither can
     acquire an exclusive lock for the row because of the shared lock
     held by the other.

   * *Note `INSERT ... ON DUPLICATE KEY UPDATE': insert-on-duplicate.
     differs from a simple *Note `INSERT': insert. in that an exclusive
     next-key lock rather than a shared lock is placed on the row to be
     updated when a duplicate-key error occurs.

   * *Note `REPLACE': replace. is done like an *Note `INSERT': insert.
     if there is no collision on a unique key. Otherwise, an exclusive
     next-key lock is placed on the row to be replaced.

   * `INSERT INTO T SELECT ... FROM S WHERE ...' sets an exclusive
     index record without a gap lock on each row inserted into `T'. If
     `innodb_locks_unsafe_for_binlog' is enabled and the transaction
     isolation level is not `SERIALIZABLE', `InnoDB' does the search on
     `S' as a consistent read (no locks).  Otherwise, `InnoDB' sets
     shared next-key locks on rows from `S'.  `InnoDB' has to set locks
     in the latter case: In roll-forward recovery from a backup, every
     SQL statement must be executed in exactly the same way it was done
     originally.

     *Note `CREATE TABLE ... SELECT ...': create-table. performs the
     *Note `SELECT': select. with shared next-key locks or as a
     consistent read, as for *Note `INSERT ... SELECT': insert-select.

     For `REPLACE INTO T SELECT ... FROM S WHERE ...', `InnoDB' sets
     shared next-key locks on rows from `S'.

   * While initializing a previously specified `AUTO_INCREMENT' column
     on a table, `InnoDB' sets an exclusive lock on the end of the
     index associated with the `AUTO_INCREMENT' column. In accessing the
     auto-increment counter, `InnoDB' uses a specific `AUTO-INC' table
     lock mode where the lock lasts only to the end of the current SQL
     statement, not to the end of the entire transaction. Other sessions
     cannot insert into the table while the `AUTO-INC' table lock is
     held; see *Note innodb-transaction-model::.

     `InnoDB' fetches the value of a previously initialized
     `AUTO_INCREMENT' column without setting any locks.

   * If a `FOREIGN KEY' constraint is defined on a table, any insert,
     update, or delete that requires the constraint condition to be
     checked sets shared record-level locks on the records that it
     looks at to check the constraint. `InnoDB' also sets these locks
     in the case where the constraint fails.

   * *Note `LOCK TABLES': lock-tables. sets table locks, but it is the
     higher MySQL layer above the `InnoDB' layer that sets these locks.
     `InnoDB' is aware of table locks if `innodb_table_locks = 1' (the
     default) and `autocommit = 0', and the MySQL layer above `InnoDB'
     knows about row-level locks.

     Otherwise, `InnoDB''s automatic deadlock detection cannot detect
     deadlocks where such table locks are involved. Also, because in
     this case the higher MySQL layer does not know about row-level
     locks, it is possible to get a table lock on a table where another
     session currently has row-level locks. However, this does not
     endanger transaction integrity, as discussed in *Note
     innodb-deadlock-detection::. See also *Note innodb-restrictions::.


File: manual.info,  Node: innodb-implicit-commit,  Next: innodb-deadlock-detection,  Prev: innodb-locks-set,  Up: innodb-transaction-model

14.2.8.7 Implicit Transaction Commit and Rollback
.................................................

By default, MySQL starts the session for each new connection with
autocommit mode enabled, so MySQL does a commit after each SQL
statement if that statement did not return an error. If a statement
returns an error, the commit or rollback behavior depends on the error.
See *Note innodb-error-handling::.

If a session that has autocommit disabled ends without explicitly
committing the final transaction, MySQL rolls back that transaction.

Some statements implicitly end a transaction, as if you had done a
*Note `COMMIT': commit. before executing the statement. For details,
see *Note implicit-commit::.


File: manual.info,  Node: innodb-deadlock-detection,  Next: innodb-deadlocks,  Prev: innodb-implicit-commit,  Up: innodb-transaction-model

14.2.8.8 Deadlock Detection and Rollback
........................................

`InnoDB' automatically detects transaction deadlocks and rolls back a
transaction or transactions to break the deadlock. `InnoDB' tries to
pick small transactions to roll back, where the size of a transaction is
determined by the number of rows inserted, updated, or deleted.

`InnoDB' is aware of table locks if `innodb_table_locks = 1' (the
default) and `autocommit = 0', and the MySQL layer above it knows about
row-level locks. Otherwise, `InnoDB' cannot detect deadlocks where a
table lock set by a MySQL *Note `LOCK TABLES': lock-tables.  statement
or a lock set by a storage engine other than `InnoDB' is involved. You
must resolve these situations by setting the value of the
`innodb_lock_wait_timeout' system variable.

When `InnoDB' performs a complete rollback of a transaction, all locks
set by the transaction are released.  However, if just a single SQL
statement is rolled back as a result of an error, some of the locks set
by the statement may be preserved. This happens because `InnoDB' stores
row locks in a format such that it cannot know afterward which lock was
set by which statement.


File: manual.info,  Node: innodb-deadlocks,  Prev: innodb-deadlock-detection,  Up: innodb-transaction-model

14.2.8.9 How to Cope with Deadlocks
...................................

Deadlocks are a classic problem in transactional databases, but they
are not dangerous unless they are so frequent that you cannot run
certain transactions at all. Normally, you must write your applications
so that they are always prepared to re-issue a transaction if it gets
rolled back because of a deadlock.

`InnoDB' uses automatic row-level locking. You can get deadlocks even
in the case of transactions that just insert or delete a single row.
That is because these operations are not really `atomic'; they
automatically set locks on the (possibly several) index records of the
row inserted or deleted.

You can cope with deadlocks and reduce the likelihood of their
occurrence with the following techniques:

   * Use *Note `SHOW ENGINE INNODB STATUS': show-engine. to determine
     the cause of the latest deadlock. That can help you to tune your
     application to avoid deadlocks.

   * Always be prepared to re-issue a transaction if it fails due to
     deadlock. Deadlocks are not dangerous. Just try again.

   * Commit your transactions often. Small transactions are less prone
     to collision.

   * If you are using locking reads (*Note `SELECT ... FOR UPDATE':
     select. or `SELECT ...  LOCK IN SHARE MODE'), try using a lower
     isolation level such as `READ COMMITTED'.

   * Access your tables and rows in a fixed order. Then transactions
     form well-defined queues and do not deadlock.

   * Add well-chosen indexes to your tables. Then your queries need to
     scan fewer index records and consequently set fewer locks. Use
     *Note `EXPLAIN SELECT': explain. to determine which indexes the
     MySQL server regards as the most appropriate for your queries.

   * Use less locking. If you can afford to permit a *Note `SELECT':
     select. to return data from an old snapshot, do not add the clause
     `FOR UPDATE' or `LOCK IN SHARE MODE' to it. Using the `READ
     COMMITTED' isolation level is good here, because each consistent
     read within the same transaction reads from its own fresh
     snapshot. You should also set the value of `innodb_support_xa' to
     0, which will reduce the number of disk flushes due to
     synchronizing on disk data and the binary log.

   * If nothing else helps, serialize your transactions with
     table-level locks. The correct way to use *Note `LOCK TABLES':
     lock-tables. with transactional tables, such as `InnoDB' tables,
     is to begin a transaction with `SET autocommit = 0' (not *Note
     `START TRANSACTION': commit.) followed by *Note `LOCK TABLES':
     lock-tables, and to not call *Note `UNLOCK TABLES': lock-tables.
     until you commit the transaction explicitly. For example, if you
     need to write to table `t1' and read from table `t2', you can do
     this:

          SET autocommit=0;
          LOCK TABLES t1 WRITE, t2 READ, ...;... DO SOMETHING WITH TABLES T1 AND T2 HERE ...
          COMMIT;
          UNLOCK TABLES;

     Table-level locks make your transactions queue nicely and avoid
     deadlocks.

   * Another way to serialize transactions is to create an auxiliary
     `semaphore' table that contains just a single row. Have each
     transaction update that row before accessing other tables. In that
     way, all transactions happen in a serial fashion. Note that the
     `InnoDB' instant deadlock detection algorithm also works in this
     case, because the serializing lock is a row-level lock. With MySQL
     table-level locks, the timeout method must be used to resolve
     deadlocks.


File: manual.info,  Node: innodb-multi-versioning,  Next: innodb-table-and-index,  Prev: innodb-transaction-model,  Up: innodb-storage-engine

14.2.9 `InnoDB' Multi-Versioning
--------------------------------

Because `InnoDB' is a multi-versioned storage engine, it must keep
information about old versions of rows in the tablespace. This
information is stored in a data structure called a _rollback segment_
(after an analogous data structure in Oracle).

Internally, `InnoDB' adds three fields to each row stored in the
database. A 6-byte `DB_TRX_ID' field indicates the transaction
identifier for the last transaction that inserted or updated the row.
Also, a deletion is treated internally as an update where a special bit
in the row is set to mark it as deleted. Each row also contains a 7-byte
`DB_ROLL_PTR' field called the roll pointer. The roll pointer points to
an undo log record written to the rollback segment. If the row was
updated, the undo log record contains the information necessary to
rebuild the content of the row before it was updated. A 6-byte
`DB_ROW_ID' field contains a row ID that increases monotonically as new
rows are inserted. If `InnoDB' generates a clustered index
automatically, the index contains row ID values. Otherwise, the
`DB_ROW_ID' column does not appear in any index.

`InnoDB' uses the information in the rollback segment to perform the
undo operations needed in a transaction rollback. It also uses the
information to build earlier versions of a row for a consistent read.

Undo logs in the rollback segment are divided into insert and update
undo logs. Insert undo logs are needed only in transaction rollback and
can be discarded as soon as the transaction commits.  Update undo logs
are used also in consistent reads, but they can be discarded only after
there is no transaction present for which `InnoDB' has assigned a
snapshot that in a consistent read could need the information in the
update undo log to build an earlier version of a database row.

You must remember to commit your transactions regularly, including
those transactions that issue only consistent reads. Otherwise,
`InnoDB' cannot discard data from the update undo logs, and the
rollback segment may grow too big, filling up your tablespace.

The physical size of an undo log record in the rollback segment is
typically smaller than the corresponding inserted or updated row.  You
can use this information to calculate the space need for your rollback
segment.

In the `InnoDB' multi-versioning scheme, a row is not physically
removed from the database immediately when you delete it with an SQL
statement. Only when `InnoDB' can discard the update undo log record
written for the deletion can it also physically remove the
corresponding row and its index records from the database. This removal
operation is called a purge, and it is quite fast, usually taking the
same order of time as the SQL statement that did the deletion.

In a scenario where the user inserts and deletes rows in smallish
batches at about the same rate in the table, it is possible that the
purge thread starts to lag behind, and the table grows bigger and
bigger, making everything disk-bound and very slow. Even if the table
carries just 10MB of useful data, it may grow to occupy 10GB with all
the `dead' rows. In such a case, it would be good to throttle new row
operations and allocate more resources to the purge thread. The
`innodb_max_purge_lag' system variable exists for exactly this purpose.
See *Note innodb-parameters::, for more information.


File: manual.info,  Node: innodb-table-and-index,  Next: innodb-disk-management,  Prev: innodb-multi-versioning,  Up: innodb-storage-engine

14.2.10 `InnoDB' Table and Index Structures
-------------------------------------------

* Menu:

* innodb-index-types::           Clustered and Secondary Indexes
* innodb-physical-structure::    Physical Structure of an Index
* innodb-insert-buffering::      Insert Buffering
* innodb-adaptive-hash::         Adaptive Hash Indexes
* innodb-physical-record::       Physical Row Structure

MySQL stores its data dictionary information for tables in `.frm' files
in database directories. This is true for all MySQL storage engines,
but every `InnoDB' table also has its own entry in the `InnoDB'
internal data dictionary inside the tablespace. When MySQL drops a
table or a database, it has to delete one or more `.frm' files as well
as the corresponding entries inside the `InnoDB' data dictionary.
Consequently, you cannot move `InnoDB' tables between databases simply
by moving the `.frm' files.


File: manual.info,  Node: innodb-index-types,  Next: innodb-physical-structure,  Prev: innodb-table-and-index,  Up: innodb-table-and-index

14.2.10.1 Clustered and Secondary Indexes
.........................................

Every `InnoDB' table has a special index called the _clustered index_
where the data for the rows is stored:

   * If you define a `PRIMARY KEY' on your table, `InnoDB' uses it as
     the clustered index.

   * If you do not define a `PRIMARY KEY' for your table, MySQL picks
     the first `UNIQUE' index that has only `NOT NULL' columns as the
     primary key and `InnoDB' uses it as the clustered index.

   * If the table has no `PRIMARY KEY' or suitable `UNIQUE' index,
     `InnoDB' internally generates a hidden clustered index on a
     synthetic column containing row ID values. The rows are ordered by
     the ID that `InnoDB' assigns to the rows in such a table. The row
     ID is a 6-byte field that increases monotonically as new rows are
     inserted. Thus, the rows ordered by the row ID are physically in
     insertion order.

Accessing a row through the clustered index is fast because the row
data is on the same page where the index search leads. If a table is
large, the clustered index architecture often saves a disk I/O
operation when compared to storage organizations that store row data
using a different page from the index record.  (For example, `MyISAM'
uses one file for data rows and another for index records.)

In `InnoDB', the records in nonclustered indexes (also called secondary
indexes) contain the primary key columns for the row that are not in
the secondary index.  `InnoDB' uses this primary key value to search
for the row in the clustered index. If the primary key is long, the
secondary indexes use more space, so it is advantageous to have a short
primary key.


File: manual.info,  Node: innodb-physical-structure,  Next: innodb-insert-buffering,  Prev: innodb-index-types,  Up: innodb-table-and-index

14.2.10.2 Physical Structure of an Index
........................................

All `InnoDB' indexes are B-trees where the index records are stored in
the leaf pages of the tree. The default size of an index page is 16KB.
When new records are inserted, `InnoDB' tries to leave 1/16 of the page
free for future insertions and updates of the index records.

If index records are inserted in a sequential order (ascending or
descending), the resulting index pages are about 15/16 full.  If
records are inserted in a random order, the pages are from 1/2 to 15/16
full. If the fill factor of an index page drops below 1/2, `InnoDB'
tries to contract the index tree to free the page.

*Note*:

Changing the page size is not a supported operation and there is no
guarantee that *Note `InnoDB': innodb-storage-engine. will function
normally with a page size other than 16KB. Problems compiling or
running InnoDB may occur.

A version of *Note `InnoDB': innodb-storage-engine. built for one page
size cannot use data files or log files from a version built for a
different page size.


File: manual.info,  Node: innodb-insert-buffering,  Next: innodb-adaptive-hash,  Prev: innodb-physical-structure,  Up: innodb-table-and-index

14.2.10.3 Insert Buffering
..........................

It is a common situation in database applications that the primary key
is a unique identifier and new rows are inserted in the ascending order
of the primary key. Thus, insertions into the clustered index do not
require random reads from a disk.

On the other hand, secondary indexes are usually nonunique, and
insertions into secondary indexes happen in a relatively random order.
This would cause a lot of random disk I/O operations without a special
mechanism used in `InnoDB'.

If an index record should be inserted into a nonunique secondary index,
`InnoDB' checks whether the secondary index page is in the buffer pool.
If that is the case, `InnoDB' does the insertion directly to the index
page. If the index page is not found in the buffer pool, `InnoDB'
inserts the record to a special insert buffer structure. The insert
buffer is kept so small that it fits entirely in the buffer pool, and
insertions can be done very fast.

Periodically, the insert buffer is merged into the secondary index
trees in the database. Often it is possible to merge several insertions
into the same page of the index tree, saving disk I/O operations. It
has been measured that the insert buffer can speed up insertions into a
table up to 15 times.

The insert buffer merging may continue to happen _after_ the inserting
transaction has been committed. In fact, it may continue to happen
after a server shutdown and restart (see *Note
forcing-innodb-recovery::).

Insert buffer merging may take many hours when many secondary indexes
must be updated and many rows have been inserted. During this time,
disk I/O will be increased, which can cause significant slowdown on
disk-bound queries. Another significant background I/O operation is the
purge thread (see *Note innodb-multi-versioning::).


File: manual.info,  Node: innodb-adaptive-hash,  Next: innodb-physical-record,  Prev: innodb-insert-buffering,  Up: innodb-table-and-index

14.2.10.4 Adaptive Hash Indexes
...............................

If a table fits almost entirely in main memory, the fastest way to
perform queries on it is to use hash indexes.  `InnoDB' has a mechanism
that monitors index searches made to the indexes defined for a table. If
`InnoDB' notices that queries could benefit from building a hash index,
it does so automatically.

The hash index is always built based on an existing B-tree index on the
table. `InnoDB' can build a hash index on a prefix of any length of the
key defined for the B-tree, depending on the pattern of searches that
`InnoDB' observes for the B-tree index. A hash index can be partial: It
is not required that the whole B-tree index is cached in the buffer
pool. `InnoDB' builds hash indexes on demand for those pages of the
index that are often accessed.

In a sense, `InnoDB' tailors itself through the adaptive hash index
mechanism to ample main memory, coming closer to the architecture of
main-memory databases.


File: manual.info,  Node: innodb-physical-record,  Prev: innodb-adaptive-hash,  Up: innodb-table-and-index

14.2.10.5 Physical Row Structure
................................

The physical row structure for an `InnoDB' table depends on the MySQL
version and the optional `ROW_FORMAT' option used when the table was
created. For `InnoDB' tables in MySQL 5.0.3 and earlier, only the
`REDUNDANT' row format was available. For MySQL 5.0.3 and later, the
default is to use the `COMPACT' row format, but you can use the
`REDUNDANT' format to retain compatibility with older versions of
`InnoDB' tables. To check the row format of an `InnoDB' table use *Note
`SHOW TABLE STATUS': show-table-status.

The compact row format decreases row storage space by about 20% at the
cost of increasing CPU use for some operations. If your workload is a
typical one that is limited by cache hit rates and disk speed, compact
format is likely to be faster. If the workload is a rare case that is
limited by CPU speed, compact format might be slower.

Rows in `InnoDB' tables that use `REDUNDANT' row format have the
following characteristics:

   * Each index record contains a six-byte header. The header is used
     to link together consecutive records, and also in row-level
     locking.

   * Records in the clustered index contain fields for all user-defined
     columns. In addition, there is a six-byte transaction ID field and
     a seven-byte roll pointer field.

   * If no primary key was defined for a table, each clustered index
     record also contains a six-byte row ID field.

   * Each secondary index record also contains all the primary key
     fields defined for the clustered index key that are not in the
     secondary index.

   * A record contains a pointer to each field of the record. If the
     total length of the fields in a record is less than 128 bytes, the
     pointer is one byte; otherwise, two bytes. The array of these
     pointers is called the record directory. The area where these
     pointers point is called the data part of the record.

   * Internally, `InnoDB' stores fixed-length character columns such as
     *Note `CHAR(10)': char. in a fixed-length format. Before MySQL
     5.0.3, `InnoDB' truncates trailing spaces from *Note `VARCHAR':
     char. columns.

   * An SQL `NULL' value reserves one or two bytes in the record
     directory. Besides that, an SQL `NULL' value reserves zero bytes
     in the data part of the record if stored in a variable length
     column. In a fixed-length column, it reserves the fixed length of
     the column in the data part of the record.  Reserving the fixed
     space for `NULL' values enables an update of the column from `NULL'
     to a non-`NULL' value to be done in place without causing
     fragmentation of the index page.

Rows in `InnoDB' tables that use `COMPACT' row format have the following
characteristics:

   * Each index record contains a five-byte header that may be preceded
     by a variable-length header. The header is used to link together
     consecutive records, and also in row-level locking.

   * The variable-length part of the record header contains a bit
     vector for indicating `NULL' columns. If the number of columns in
     the index that can be `NULL' is N, the bit vector occupies
     `CEILING(N/8)' bytes. (For example, if there are anywhere from 9
     to 15 columns that can be `NULL', the bit vector uses two bytes.)
     Columns that are `NULL' do not occupy space other than the bit in
     this vector. The variable-length part of the header also contains
     the lengths of variable-length columns. Each length takes one or
     two bytes, depending on the maximum length of the column. If all
     columns in the index are `NOT NULL' and have a fixed length, the
     record header has no variable-length part.

   * For each non-`NULL' variable-length field, the record header
     contains the length of the column in one or two bytes. Two bytes
     will only be needed if part of the column is stored externally in
     overflow pages or the maximum length exceeds 255 bytes and the
     actual length exceeds 127 bytes. For an externally stored column,
     the two-byte length indicates the length of the internally stored
     part plus the 20-byte pointer to the externally stored part. The
     internal part is 768 bytes, so the length is 768+20. The 20-byte
     pointer stores the true length of the column.

   * The record header is followed by the data contents of the
     non-`NULL' columns.

   * Records in the clustered index contain fields for all user-defined
     columns. In addition, there is a six-byte transaction ID field and
     a seven-byte roll pointer field.

   * If no primary key was defined for a table, each clustered index
     record also contains a six-byte row ID field.

   * Each secondary index record also contains all the primary key
     fields defined for the clustered index key that are not in the
     secondary index. If any of these primary key fields are variable
     length, the record header for each secondary index will have a
     variable-length part to record their lengths, even if the
     secondary index is defined on fixed-length columns.

   * Internally, `InnoDB' stores fixed-length, fixed-width character
     columns such as *Note `CHAR(10)': char. in a fixed-length format.
     Before MySQL 5.0.3, `InnoDB' truncates trailing spaces from *Note
     `VARCHAR': char. columns.

   * Internally, `InnoDB' attempts to store UTF-8 *Note `CHAR(N)': char.
     columns in N bytes by trimming trailing spaces. (With `REDUNDANT'
     row format, such columns occupy 3 x N bytes.) Reserving the minimum
     space N in many cases enables column updates to be done in place
     without causing fragmentation of the index page.


File: manual.info,  Node: innodb-disk-management,  Next: innodb-error-handling,  Prev: innodb-table-and-index,  Up: innodb-storage-engine

14.2.11 `InnoDB' Disk I/O and File Space Management
---------------------------------------------------

* Menu:

* innodb-disk-io::               `InnoDB' Disk I/O
* innodb-file-space::            File Space Management
* innodb-file-defragmenting::    Defragmenting a Table


File: manual.info,  Node: innodb-disk-io,  Next: innodb-file-space,  Prev: innodb-disk-management,  Up: innodb-disk-management

14.2.11.1 `InnoDB' Disk I/O
...........................

`InnoDB' uses simulated asynchronous disk I/O: `InnoDB' creates a
number of threads to take care of I/O operations, such as read-ahead.

There are two read-ahead heuristics in `InnoDB':

   * In sequential read-ahead, if `InnoDB' notices that the access
     pattern to a segment in the tablespace is sequential, it posts in
     advance a batch of reads of database pages to the I/O system.

   * In random read-ahead, if `InnoDB' notices that some area in a
     tablespace seems to be in the process of being fully read into the
     buffer pool, it posts the remaining reads to the I/O system.

`InnoDB' uses a novel file flush technique called _doublewrite_. It
adds safety to recovery following an operating system crash or a power
outage, and improves performance on most varieties of Unix by reducing
the need for `fsync()' operations.

Doublewrite means that before writing pages to a data file, `InnoDB'
first writes them to a contiguous tablespace area called the
doublewrite buffer. Only after the write and the flush to the
doublewrite buffer has completed does `InnoDB' write the pages to their
proper positions in the data file. If the operating system crashes in
the middle of a page write, `InnoDB' can later find a good copy of the
page from the doublewrite buffer during recovery.


File: manual.info,  Node: innodb-file-space,  Next: innodb-file-defragmenting,  Prev: innodb-disk-io,  Up: innodb-disk-management

14.2.11.2 File Space Management
...............................

The data files that you define in the configuration file form the
`InnoDB' tablespace. The files are logically concatenated to form the
tablespace. There is no striping in use. Currently, you cannot define
where within the tablespace your tables are allocated. However, in a
newly created tablespace, `InnoDB' allocates space starting from the
first data file.

The tablespace consists of database pages with a default size of 16KB.
The pages are grouped into extents of size 1MB (64 consecutive pages).
The `files' inside a tablespace are called _segments_ in `InnoDB'. The
term `rollback segment' is somewhat confusing because it actually
contains many tablespace segments.

When a segment grows inside the tablespace, `InnoDB' allocates the
first 32 pages to it individually. After that, `InnoDB' starts to
allocate whole extents to the segment. `InnoDB' can add up to 4 extents
at a time to a large segment to ensure good sequentiality of data.

Two segments are allocated for each index in `InnoDB'. One is for
nonleaf nodes of the B-tree, the other is for the leaf nodes. The idea
here is to achieve better sequentiality for the leaf nodes, which
contain the data.

Some pages in the tablespace contain bitmaps of other pages, and
therefore a few extents in an `InnoDB' tablespace cannot be allocated
to segments as a whole, but only as individual pages.

When you ask for available free space in the tablespace by issuing a
*Note `SHOW TABLE STATUS': show-table-status.  statement, `InnoDB'
reports the extents that are definitely free in the tablespace. `InnoDB'
always reserves some extents for cleanup and other internal purposes;
these reserved extents are not included in the free space.

When you delete data from a table, `InnoDB' contracts the corresponding
B-tree indexes. Whether the freed space becomes available for other
users depends on whether the pattern of deletes frees individual pages
or extents to the tablespace. Dropping a table or deleting all rows
from it is guaranteed to release the space to other users, but remember
that deleted rows are physically removed only in an (automatic) purge
operation after they are no longer needed for transaction rollbacks or
consistent reads. (See *Note innodb-multi-versioning::.)

To see information about the tablespace, use the Tablespace Monitor.
See *Note innodb-monitors::.

The maximum row length, except for variable-length columns (*Note
`VARBINARY': binary-varbinary, *Note `VARCHAR': char, *Note `BLOB':
blob. and *Note `TEXT': blob.), is slightly less than half of a
database page. That is, the maximum row length is about 8000 bytes.
*Note `LONGBLOB': blob. and *Note `LONGTEXT': blob. columns must be
less than 4GB, and the total row length, including *Note `BLOB': blob.
and *Note `TEXT': blob. columns, must be less than 4GB.

If a row is less than half a page long, all of it is stored locally
within the page. If it exceeds half a page, variable-length columns are
chosen for external off-page storage until the row fits within half a
page. For a column chosen for off-page storage, `InnoDB' stores the
first 768 bytes locally in the row, and the rest externally into
overflow pages. Each such column has its own list of overflow pages. The
768-byte prefix is accompanied by a 20-byte value that stores the true
length of the column and points into the overflow list where the rest
of the value is stored.


File: manual.info,  Node: innodb-file-defragmenting,  Prev: innodb-file-space,  Up: innodb-disk-management

14.2.11.3 Defragmenting a Table
...............................

If there are random insertions into or deletions from the indexes of a
table, the indexes may become fragmented.  Fragmentation means that the
physical ordering of the index pages on the disk is not close to the
index ordering of the records on the pages, or that there are many
unused pages in the 64-page blocks that were allocated to the index.

One symptom of fragmentation is that a table takes more space than it
`should' take. How much that is exactly, is difficult to determine. All
`InnoDB' data and indexes are stored in B-trees, and their fill factor
may vary from 50% to 100%. Another symptom of fragmentation is that a
table scan such as this takes more time than it `should' take:

     SELECT COUNT(*) FROM t WHERE a_non_indexed_column <> 12345;

(In the preceding query, we are `fooling' the SQL optimizer into
scanning the clustered index rather than a secondary index.) Most disks
can read 10MB/s to 50MB/s, which can be used to estimate how fast a
table scan should be.

It can speed up index scans if you periodically perform a `null' *Note
`ALTER TABLE': alter-table.  operation, which causes MySQL to rebuild
the table:

     ALTER TABLE TBL_NAME ENGINE=INNODB

Another way to perform a defragmentation operation is to use *Note
`mysqldump': mysqldump. to dump the table to a text file, drop the
table, and reload it from the dump file.

If the insertions into an index are always ascending and records are
deleted only from the end, the `InnoDB' filespace management algorithm
guarantees that fragmentation in the index does not occur.


File: manual.info,  Node: innodb-error-handling,  Next: innodb-tuning-troubleshooting,  Prev: innodb-disk-management,  Up: innodb-storage-engine

14.2.12 `InnoDB' Error Handling
-------------------------------

* Menu:

* innodb-error-codes::           `InnoDB' Error Codes
* operating-system-error-codes::  Operating System Error Codes

Error handling in `InnoDB' is not always the same as specified in the
SQL standard. According to the standard, any error during an SQL
statement should cause rollback of that statement. `InnoDB' sometimes
rolls back only part of the statement, or the whole transaction. The
following items describe how `InnoDB' performs error handling:

   * If you run out of file space in the tablespace, a MySQL `Table is
     full' error occurs and `InnoDB' rolls back the SQL statement.

   * A transaction deadlock causes `InnoDB' to roll back the entire
     transaction. You should normally retry the whole transaction when
     this happens.

     A lock wait timeout causes `InnoDB' to roll back only the single
     statement that was waiting for the lock and encountered the
     timeout. (Until MySQL 5.0.13 `InnoDB' rolled back the entire
     transaction if a lock wait timeout happened. You can restore this
     behavior by starting the server with the
     `--innodb_rollback_on_timeout' option, available as of MySQL
     5.0.32.) You should normally retry the statement if using the
     current behavior or the entire transaction if using the old
     behavior.

     Both deadlocks and lock wait timeouts are normal on busy servers
     and it is necessary for applications to be aware that they may
     happen and handle them by retrying. You can make them less likely
     by doing as little work as possible between the first change to
     data during a transaction and the commit, so the locks are held
     for the shortest possible time and for the smallest possible
     number of rows. Sometimes splitting work between different
     transactions may be practical and helpful.

     When a transaction rollback occurs due to a deadlock or lock wait
     timeout, it cancels the effect of the statements within the
     transaction. But if the start-transaction statement was *Note
     `START TRANSACTION': commit. or *Note `BEGIN': commit.  statement,
     rollback does not cancel that statement. Further SQL statements
     become part of the transaction until the occurrence of *Note
     `COMMIT': commit, *Note `ROLLBACK': commit, or some SQL statement
     that causes an implicit commit.

   * A duplicate-key error rolls back the SQL statement, if you have
     not specified the `IGNORE' option in your statement.

   * A `row too long error' rolls back the SQL statement.

   * Other errors are mostly detected by the MySQL layer of code (above
     the `InnoDB' storage engine level), and they roll back the
     corresponding SQL statement. Locks are not released in a rollback
     of a single SQL statement.

During implicit rollbacks, as well as during the execution of an
explicit *Note `ROLLBACK': commit. SQL statement, *Note `SHOW
PROCESSLIST': show-processlist.  displays `Rolling back' in the `State'
column for the relevant connection.


File: manual.info,  Node: innodb-error-codes,  Next: operating-system-error-codes,  Prev: innodb-error-handling,  Up: innodb-error-handling

14.2.12.1 `InnoDB' Error Codes
..............................

The following is a nonexhaustive list of common `InnoDB'-specific
errors that you may encounter, with information about why each occurs
and how to resolve the problem.

   * `1005 (ER_CANT_CREATE_TABLE)'

     Cannot create table. If the error message refers to error 150,
     table creation failed because a foreign key constraint was not
     correctly formed. If the error message refers to error -1, table
     creation probably failed because the table includes a column name
     that matched the name of an internal `InnoDB' table.

   * `1016 (ER_CANT_OPEN_FILE)'

     Cannot find the `InnoDB' table from the `InnoDB' data files,
     although the `.frm' file for the table exists. See *Note
     innodb-troubleshooting-datadict::.

   * `1114 (ER_RECORD_FILE_FULL)'

     `InnoDB' has run out of free space in the tablespace. You should
     reconfigure the tablespace to add a new data file.

   * `1205 (ER_LOCK_WAIT_TIMEOUT)'

     Lock wait timeout expired. Transaction was rolled back.

   * `1213 (ER_LOCK_DEADLOCK)'

     Transaction deadlock. You should rerun the transaction.

   * `1216 (ER_NO_REFERENCED_ROW)'

     You are trying to add a row but there is no parent row, and a
     foreign key constraint fails. You should add the parent row first.

   * `1217 (ER_ROW_IS_REFERENCED)'

     You are trying to delete a parent row that has children, and a
     foreign key constraint fails. You should delete the children first.


File: manual.info,  Node: operating-system-error-codes,  Prev: innodb-error-codes,  Up: innodb-error-handling

14.2.12.2 Operating System Error Codes
......................................

To print the meaning of an operating system error number, use the *Note
`perror': perror. program that comes with the MySQL distribution.

For a list of Linux-specific Error Codes, see Linux Error Codes. For a
list of Windows-specific Error Codes, see Windows Error Codes.

   *  *Linux System Error Codes*

     The following table provides a list of some common Linux system
     error codes. For a more complete list, see Linux source code
     (http://www.finalcog.com/c-error-codes-include-errno).

     Number  Macro         Description
     1       `EPERM'       Operation not permitted
     2       `ENOENT'      No such file or directory
     3       `ESRCH'       No such process
     4       `EINTR'       Interrupted system call
     5       `EIO'         I/O error
     6       `ENXIO'       No such device or address
     7       `E2BIG'       Arg list too long
     8       `ENOEXEC'     Exec format error
     9       `EBADF'       Bad file number
     10      `ECHILD'      No child processes
     11      `EAGAIN'      Try again
     12      `ENOMEM'      Out of memory
     13      `EACCES'      Permission denied
     14      `EFAULT'      Bad address
     15      `ENOTBLK'     Block device required
     16      `EBUSY'       Device or resource busy
     17      `EEXIST'      File exists
     18      `EXDEV'       Cross-device link
     19      `ENODEV'      No such device
     20      `ENOTDIR'     Not a directory
     21      `EISDIR'      Is a directory
     22      `EINVAL'      Invalid argument
     23      `ENFILE'      File table overflow
     24      `EMFILE'      Too many open files
     25      `ENOTTY'      Inappropriate ioctl for device
     26      `ETXTBSY'     Text file busy
     27      `EFBIG'       File too large
     28      `ENOSPC'      No space left on device
     29      `ESPIPE'      Illegal seek
     30      `EROFS'       Read-only file system
     31      `EMLINK'      Too many links

   *  *Windows System Error Codes*

     The following table provides a list of some common Windows system
     error codes. For a complete list, see the Microsoft Web site
     (http://msdn.microsoft.com/en-us/library/ms681381.aspx).

     Number  Macro         Description
     1       `ERROR_INVALID_FUNCTION'Incorrect function.
     2       `ERROR_FILE_NOT_FOUND'The system cannot find the file specified.
     3       `ERROR_PATH_NOT_FOUND'The system cannot find the path specified.
     4       `ERROR_TOO_MANY_OPEN_FILES'The system cannot open the file.
     5       `ERROR_ACCESS_DENIED'Access is denied.
     6       `ERROR_INVALID_HANDLE'The handle is invalid.
     7       `ERROR_ARENA_TRASHED'The storage control blocks were destroyed.
     8       `ERROR_NOT_ENOUGH_MEMORY'Not enough storage is available to process
                           this command.
     9       `ERROR_INVALID_BLOCK'The storage control block address is invalid.
     10      `ERROR_BAD_ENVIRONMENT'The environment is incorrect.
     11      `ERROR_BAD_FORMAT'An attempt was made to load a program with an
                           incorrect format.
     12      `ERROR_INVALID_ACCESS'The access code is invalid.
     13      `ERROR_INVALID_DATA'The data is invalid.
     14      `ERROR_OUTOFMEMORY'Not enough storage is available to complete
                           this operation.
     15      `ERROR_INVALID_DRIVE'The system cannot find the drive specified.
     16      `ERROR_CURRENT_DIRECTORY'The directory cannot be removed.
     17      `ERROR_NOT_SAME_DEVICE'The system cannot move the file to a different
                           disk drive.
     18      `ERROR_NO_MORE_FILES'There are no more files.
     19      `ERROR_WRITE_PROTECT'The media is write protected.
     20      `ERROR_BAD_UNIT'The system cannot find the device specified.
     21      `ERROR_NOT_READY'The device is not ready.
     22      `ERROR_BAD_COMMAND'The device does not recognize the command.
     23      `ERROR_CRC'   Data error (cyclic redundancy check).
     24      `ERROR_BAD_LENGTH'The program issued a command but the command
                           length is incorrect.
     25      `ERROR_SEEK'  The drive cannot locate a specific area or
                           track on the disk.
     26      `ERROR_NOT_DOS_DISK'The specified disk or diskette cannot be
                           accessed.
     27      `ERROR_SECTOR_NOT_FOUND'The drive cannot find the sector requested.
     28      `ERROR_OUT_OF_PAPER'The printer is out of paper.
     29      `ERROR_WRITE_FAULT'The system cannot write to the specified
                           device.
     30      `ERROR_READ_FAULT'The system cannot read from the specified
                           device.
     31      `ERROR_GEN_FAILURE'A device attached to the system is not
                           functioning.
     32      `ERROR_SHARING_VIOLATION'The process cannot access the file because it
                           is being used by another process.
     33      `ERROR_LOCK_VIOLATION'The process cannot access the file because
                           another process has locked a portion of the
                           file.
     34      `ERROR_WRONG_DISK'The wrong diskette is in the drive. Insert %2
                           (Volume Serial Number: %3) into drive %1.
     36      `ERROR_SHARING_BUFFER_EXCEEDED'Too many files opened for sharing.
     38      `ERROR_HANDLE_EOF'Reached the end of the file.
     39      `ERROR_HANDLE_DISK_FULL'The disk is full.
     87      `ERROR_INVALID_PARAMETER'The parameter is incorrect.
     112     `ERROR_DISK_FULL'The disk is full.
     123     `ERROR_INVALID_NAME'The file name, directory name, or volume label
                           syntax is incorrect.
     1450    `ERROR_NO_SYSTEM_RESOURCES'Insufficient system resources exist to
                           complete the requested service.


File: manual.info,  Node: innodb-tuning-troubleshooting,  Next: innodb-restrictions,  Prev: innodb-error-handling,  Up: innodb-storage-engine

14.2.13 `InnoDB' Performance Tuning and Troubleshooting
-------------------------------------------------------

* Menu:

* innodb-tuning::                `InnoDB' Performance Tuning Tips
* innodb-monitors::              `SHOW ENGINE INNODB STATUS' and the `InnoDB' Monitors
* innodb-troubleshooting::       `InnoDB' General Troubleshooting
* innodb-troubleshooting-datadict::  Troubleshooting `InnoDB' Data Dictionary Operations


File: manual.info,  Node: innodb-tuning,  Next: innodb-monitors,  Prev: innodb-tuning-troubleshooting,  Up: innodb-tuning-troubleshooting

14.2.13.1 `InnoDB' Performance Tuning Tips
..........................................

The followings tips are grouped by category. Some of them can apply in
multiple categories, so it is useful to read them all.

*Storage Layout Tips*

   * In `InnoDB', having a long `PRIMARY KEY' wastes a lot of disk
     space because its value must be stored with every secondary index
     record. (See *Note innodb-table-and-index::.) Create an
     `AUTO_INCREMENT' column as the primary key if your primary key is
     long.

   * Use the *Note `VARCHAR': char. data type instead of *Note `CHAR':
     char. if you are storing variable-length strings or if the column
     may contain many `NULL' values. A *Note `CHAR(N)': char.  column
     always takes N characters to store data, even if the string is
     shorter or its value is `NULL'. Smaller tables fit better in the
     buffer pool and reduce disk I/O.

     When using `COMPACT' row format (the default `InnoDB' format in
     MySQL 5.0) and variable-length character sets, such as `utf8' or
     `sjis', *Note `CHAR(N)': char.  will occupy a variable amount of
     space, at least N bytes.

*Transaction Management Tips*

   * Wrap several modifications into a single transaction to reduce the
     number of flush operations.  `InnoDB' must flush the log to disk
     at each transaction commit if that transaction made modifications
     to the database. The rotation speed of a disk is typically at most
     167 revolutions/second (for a 10,000RPM disk), which constrains
     the number of commits to the same 167^th of a second if the disk
     does not `fool' the operating system.

   * If you can afford the loss of some of the latest committed
     transactions if a crash occurs, you can set the
     `innodb_flush_log_at_trx_commit' parameter to 0. `InnoDB' tries to
     flush the log once per second anyway, although the flush is not
     guaranteed.

*Disk I/O Tips*

   * `innodb_buffer_pool_size' specifies the size of the buffer pool.
     If your buffer pool is small and you have sufficient memory,
     making the pool larger can improve performance by reducing the
     amount of disk I/O needed as queries access *Note `InnoDB':
     innodb-storage-engine. tables. For more information about the
     pool, see *Note innodb-buffer-pool::.

   * Beware of big rollbacks of mass inserts: `InnoDB' uses the insert
     buffer to save disk I/O in inserts, but no such mechanism is used
     in a corresponding rollback. A disk-bound rollback can take 30
     times as long to perform as the corresponding insert.  Killing the
     database process does not help because the rollback starts again
     on server startup. The only way to get rid of a runaway rollback
     is to increase the buffer pool so that the rollback becomes
     CPU-bound and runs fast, or to use a special procedure. See *Note
     forcing-innodb-recovery::.

   * Beware also of other big disk-bound operations. Use *Note `DROP
     TABLE': drop-table. and *Note `CREATE TABLE': create-table. to
     empty a table, not `DELETE FROM TBL_NAME'.

   * In some versions of GNU/Linux and Unix, flushing files to disk
     with the Unix `fsync()' call (which `InnoDB' uses by default) and
     other similar methods is surprisingly slow. If you are
     dissatisfied with database write performance, you might try
     setting the `innodb_flush_method' parameter to `O_DSYNC'. The
     `O_DSYNC' flush method seems to perform slower on most systems,
     but yours might not be one of them.

   * When using the `InnoDB' storage engine on Solaris 10 for x86_64
     architecture (AMD Opteron), it is important to use direct I/O for
     `InnoDB'-related files. Failure to do so may cause degradation of
     `InnoDB''s speed and performance on this platform. To use direct
     I/O for an entire UFS file system used for storing
     `InnoDB'-related files, mount it with the `forcedirectio' option;
     see `mount_ufs(1M)'. (The default on Solaris 10/x86_64 is _not_ to
     use this option.)  Alternatively, as of MySQL 5.0.42 you can set
     `innodb_flush_method = O_DIRECT' if you do not want to affect the
     entire file system. This causes `InnoDB' to call `directio()'
     instead of `fcntl()'. However, setting `innodb_flush_method' to
     `O_DIRECT' causes `InnoDB' to use direct I/O only for data files,
     not the log files.

     When using the `InnoDB' storage engine with a large
     `innodb_buffer_pool_size' value on any release of Solaris 2.6 and
     up and any platform (sparc/x86/x64/amd64), a significant
     performance gain might be achieved by placing `InnoDB' data files
     and log files on raw devices or on a separate direct I/O UFS file
     system using the `forcedirectio' mount option as described earlier
     (it is necessary to use the mount option rather than setting
     `innodb_flush_method' if you want direct I/O for the log files).
     Users of the Veritas file system VxFS should use the
     `convosync=direct' mount option. You are advised to perform tests
     with and without raw partitions or direct I/O file systems to
     verify whether performance is improved on your system.

     Other MySQL data files, such as those for `MyISAM' tables, should
     not be placed on a direct I/O file system. Executables or libraries
     _must not_ be placed on a direct I/O file system.

   * If the Unix `top' tool or the Windows Task Manager shows that the
     CPU usage percentage with your workload is less than 70%, your
     workload is probably disk-bound. Maybe you are making too many
     transaction commits, or the buffer pool is too small. Making the
     buffer pool bigger can help, but do not set it equal to more than
     80% of physical memory.

*Logging Tips*

   * Make your log files big, even as big as the buffer pool.  When
     `InnoDB' has written the log files full, it must write the
     modified contents of the buffer pool to disk in a checkpoint.
     Small log files cause many unnecessary disk writes. The
     disadvantage of big log files is that the recovery time is longer.

   * Make the log buffer quite large as well (on the order of 8MB).

*Bulk Data Loading Tips*

   * When importing data into `InnoDB', make sure that MySQL does not
     have autocommit mode enabled because that requires a log flush to
     disk for every insert.  To disable autocommit during your import
     operation, surround it with *Note `SET autocommit': commit. and
     *Note `COMMIT': commit. statements:

          SET autocommit=0;... SQL IMPORT STATEMENTS ...
          COMMIT;

     If you use the *Note `mysqldump': mysqldump. option `--opt', you
     get dump files that are fast to import into an `InnoDB' table,
     even without wrapping them with the *Note `SET autocommit':
     commit. and *Note `COMMIT': commit. statements.

   * If you have `UNIQUE' constraints on secondary keys, you can speed
     up table imports by temporarily turning off the uniqueness checks
     during the import session:

          SET unique_checks=0;... SQL IMPORT STATEMENTS ...
          SET unique_checks=1;

     For big tables, this saves a lot of disk I/O because `InnoDB' can
     use its insert buffer to write secondary index records in a batch.
     Be certain that the data contains no duplicate keys.

   * If you have `FOREIGN KEY' constraints in your tables, you can
     speed up table imports by turning the foreign key checks off for
     the duration of the import session:

          SET foreign_key_checks=0;... SQL IMPORT STATEMENTS ...
          SET foreign_key_checks=1;

     For big tables, this can save a lot of disk I/O.

*Other Tips*

   * Unlike `MyISAM', `InnoDB' does not store an index cardinality
     value in its tables.  Instead, `InnoDB' computes a cardinality for
     a table the first time it accesses it after startup.  With a large
     number of tables, this might take significant time. It is the
     initial table open operation that is important, so to `warm up' a
     table for later use, access it immediately after startup by
     issuing a statement such as `SELECT 1 FROM TBL_NAME LIMIT 1'.

   * Use the multiple-row *Note `INSERT': insert.  syntax to reduce
     communication overhead between the client and the server if you
     need to insert many rows:

          INSERT INTO yourtable VALUES (1,2), (5,5), ...;

     This tip is valid for inserts into any table, not just `InnoDB'
     tables.

   * If you often have recurring queries for tables that are not
     updated frequently, enable the query cache:

          [mysqld]
          query_cache_type = 1
          query_cache_size = 10M


File: manual.info,  Node: innodb-monitors,  Next: innodb-troubleshooting,  Prev: innodb-tuning,  Up: innodb-tuning-troubleshooting

14.2.13.2 `SHOW ENGINE INNODB STATUS' and the `InnoDB' Monitors
...............................................................

* Menu:

* innodb-standard-monitor::      `InnoDB' Standard Monitor and Lock Monitor Output
* innodb-tablespace-monitor::    `InnoDB' Tablespace Monitor Output
* innodb-table-monitor::         `InnoDB' Table Monitor Output

`InnoDB' Monitors provide information about the `InnoDB' internal
state. This information is useful for performance tuning. Each Monitor
can be enabled by creating a table with a special name, which causes
`InnoDB' to write Monitor output periodically.  Also, output for the
standard `InnoDB' Monitor is available on demand through the *Note
`SHOW ENGINE INNODB STATUS': show-engine. SQL statement.

There are several types of `InnoDB' Monitors:

   * The standard `InnoDB' Monitor displays the following types of
     information:

        * Table and record locks held by each active transaction

        * Lock waits of a transactions

        * Semaphore waits of threads

        * Pending file I/O requests

        * Buffer pool statistics

        * Purge and insert buffer merge activity of the main `InnoDB'
          thread

     For a discussion of `InnoDB' lock modes, see *Note
     innodb-lock-modes::.

     To enable the standard `InnoDB' Monitor for periodic output,
     create a table named `innodb_monitor'. To obtain Monitor output on
     demand, use the *Note `SHOW ENGINE INNODB STATUS': show-engine.
     SQL statement to fetch the output to your client program. If you
     are using the *Note `mysql': mysql. interactive client, the output
     is more readable if you replace the usual semicolon statement
     terminator with `\G':

          mysql> SHOW ENGINE INNODB STATUS\G

   * The `InnoDB' Lock Monitor is like the standard Monitor but also
     provides extensive lock information. To enable this Monitor for
     periodic output, create a table named `innodb_lock_monitor'.

   * The `InnoDB' Tablespace Monitor prints a list of file segments in
     the shared tablespace and validates the tablespace allocation data
     structures. To enable this Monitor for periodic output, create a
     table named `innodb_tablespace_monitor'.

   * The `InnoDB' Table Monitor prints the contents of the `InnoDB'
     internal data dictionary. To enable this Monitor for periodic
     output, create a table named `innodb_table_monitor'.

To enable an `InnoDB' Monitor for periodic output, use a `CREATE TABLE'
statement to create the table associated with the Monitor. For example,
to enable the standard `InnoDB' Monitor, create the `innodb_monitor'
table:

     CREATE TABLE innodb_monitor (a INT) ENGINE=INNODB;

To stop the Monitor, drop the table:

     DROP TABLE innodb_monitor;

The *Note `CREATE TABLE': create-table. syntax is just a way to pass a
command to the `InnoDB' engine through MySQL's SQL parser: The only
things that matter are the table name `innodb_monitor' and that it be an
`InnoDB' table. The structure of the table is not relevant at all for
the `InnoDB' Monitor.  If you shut down the server, the Monitor does
not restart automatically when you restart the server. You must drop the
Monitor table and issue a new *Note `CREATE TABLE': create-table.
statement to start the Monitor. (This syntax may change in a future
release.)

When you enable `InnoDB' Monitors for periodic output, `InnoDB' writes
their output to the *Note `mysqld': mysqld. server standard error output
(`stderr'). In this case, no output is sent to clients. When switched
on, `InnoDB' Monitors print data about every 15 seconds. Server output
usually is directed to the error log (see *Note error-log::).  This
data is useful in performance tuning. On Windows, you must start the
server from a command prompt in a console window with the `--console'
option if you want to direct the output to the window rather than to
the error log.

`InnoDB' sends diagnostic output to `stderr' or to files rather than to
`stdout' or fixed-size memory buffers, to avoid potential buffer
overflows. As a side effect, the output of *Note `SHOW ENGINE INNODB
STATUS': show-engine. is written to a status file in the MySQL data
directory every fifteen seconds. The name of the file is
`innodb_status.PID', where PID is the server process ID.  `InnoDB'
removes the file for a normal shutdown. If abnormal shutdowns have
occurred, instances of these status files may be present and must be
removed manually.  Before removing them, you might want to examine them
to see whether they contain useful information about the cause of
abnormal shutdowns. The `innodb_status.PID' file is created only if the
configuration option `innodb-status-file=1' is set.

`InnoDB' Monitors should be enabled only when you actually want to see
Monitor information because output generation does result in some
performance decrement. Also, if you enable monitor output by creating
the associated table, your error log may become quite large if you
forget to remove the table later.

For additional information about `InnoDB' monitors, see the following
resources:

   * Mark Leith: InnoDB Table and Tablespace Monitors
     (http://www.markleith.co.uk/?p=25)

   * MySQL Performance Blog: SHOW INNODB STATUS walk through
     (http://www.mysqlperformanceblog.com/2006/07/17/show-innodb-status-walk-through/)

Each monitor begins with a header containing a timestamp and the
monitor name. For example:

     ================================================
     090407 12:06:19 INNODB TABLESPACE MONITOR OUTPUT
     ================================================

The header for the standard Monitor (`INNODB MONITOR OUTPUT') is also
used for the Lock Monitor because the latter produces the same output
with the addition of extra lock information.

The following sections describe the output for each Monitor.


File: manual.info,  Node: innodb-standard-monitor,  Next: innodb-tablespace-monitor,  Prev: innodb-monitors,  Up: innodb-monitors

14.2.13.3 `InnoDB' Standard Monitor and Lock Monitor Output
...........................................................

The Lock Monitor is the same as the standard Monitor except that it
includes additional lock information. Enabling either monitor for
periodic output by creating the associated `InnoDB' table turns on the
same output stream, but the stream includes the extra information if the
Lock Monitor is enabled. For example, if you create the
`innodb_monitor' and `innodb_lock_monitor' tables, that turns on a
single output stream. The stream includes extra lock information until
you disable the Lock Monitor by removing the `innodb_lock_monitor'
table.

Example `InnoDB' Monitor output:

     mysql> SHOW ENGINE INNODB STATUS\G
     *************************** 1. row ***************************
     Status:
     =====================================
     030709 13:00:59 INNODB MONITOR OUTPUT
     =====================================
     Per second averages calculated from the last 18 seconds
     ----------
     SEMAPHORES
     ----------
     OS WAIT ARRAY INFO: reservation count 413452, signal count 378357
     --Thread 32782 has waited at btr0sea.c line 1477 for 0.00 seconds the
     semaphore: X-lock on RW-latch at 41a28668 created in file btr0sea.c line 135
     a writer (thread id 32782) has reserved it in mode wait exclusive
     number of readers 1, waiters flag 1
     Last time read locked in file btr0sea.c line 731
     Last time write locked in file btr0sea.c line 1347
     Mutex spin waits 0, rounds 0, OS waits 0
     RW-shared spins 108462, OS waits 37964; RW-excl spins 681824, OS waits
     375485
     ------------------------
     LATEST FOREIGN KEY ERROR
     ------------------------
     030709 13:00:59 Transaction:
     TRANSACTION 0 290328284, ACTIVE 0 sec, process no 3195, OS thread id 34831
     inserting
     15 lock struct(s), heap size 2496, undo log entries 9
     MySQL thread id 25, query id 4668733 localhost heikki update
     insert into ibtest11a (D, B, C) values (5, 'khDk' ,'khDk')
     Foreign key constraint fails for table test/ibtest11a:
     ,
       CONSTRAINT `0_219242` FOREIGN KEY (`A`, `D`) REFERENCES `ibtest11b` (`A`,
       `D`) ON DELETE CASCADE ON UPDATE CASCADE
     Trying to add in child table, in index PRIMARY tuple:
      0: len 4; hex 80000101; asc ....;; 1: len 4; hex 80000005; asc ....;; 2:
      len 4; hex 6b68446b; asc khDk;; 3: len 6; hex 0000114e0edc; asc ...N..;; 4:
      len 7; hex 00000000c3e0a7; asc .......;; 5: len 4; hex 6b68446b; asc khDk;;
     But in parent table test/ibtest11b, in index PRIMARY,
     the closest match we can find is record:
     RECORD: info bits 0 0: len 4; hex 8000015b; asc ...[;; 1: len 4; hex
     80000005; asc ....;; 2: len 3; hex 6b6864; asc khd;; 3: len 6; hex
     0000111ef3eb; asc ......;; 4: len 7; hex 800001001e0084; asc .......;; 5:
     len 3; hex 6b6864; asc khd;;
     ------------------------
     LATEST DETECTED DEADLOCK
     ------------------------
     030709 12:59:58
     *** (1) TRANSACTION:
     TRANSACTION 0 290252780, ACTIVE 1 sec, process no 3185, OS thread id 30733
     inserting
     LOCK WAIT 3 lock struct(s), heap size 320, undo log entries 146
     MySQL thread id 21, query id 4553379 localhost heikki update
     INSERT INTO alex1 VALUES(86, 86, 794,'aA35818','bb','c79166','d4766t',
     'e187358f','g84586','h794',date_format('2001-04-03 12:54:22','%Y-%m-%d
     %H:%i'),7
     *** (1) WAITING FOR THIS LOCK TO BE GRANTED:
     RECORD LOCKS space id 0 page no 48310 n bits 568 table test/alex1 index
     symbole trx id 0 290252780 lock mode S waiting
     Record lock, heap no 324 RECORD: info bits 0 0: len 7; hex 61613335383138;
     asc aa35818;; 1:
     *** (2) TRANSACTION:
     TRANSACTION 0 290251546, ACTIVE 2 sec, process no 3190, OS thread id 32782
     inserting
     130 lock struct(s), heap size 11584, undo log entries 437
     MySQL thread id 23, query id 4554396 localhost heikki update
     REPLACE INTO alex1 VALUES(NULL, 32, NULL,'aa3572','','c3572','d6012t','',
     NULL,'h396', NULL, NULL, 7.31,7.31,7.31,200)
     *** (2) HOLDS THE LOCK(S):
     RECORD LOCKS space id 0 page no 48310 n bits 568 table test/alex1 index
     symbole trx id 0 290251546 lock_mode X locks rec but not gap
     Record lock, heap no 324 RECORD: info bits 0 0: len 7; hex 61613335383138;
     asc aa35818;; 1:
     *** (2) WAITING FOR THIS LOCK TO BE GRANTED:
     RECORD LOCKS space id 0 page no 48310 n bits 568 table test/alex1 index
     symbole trx id 0 290251546 lock_mode X locks gap before rec insert intention
     waiting
     Record lock, heap no 82 RECORD: info bits 0 0: len 7; hex 61613335373230;
     asc aa35720;; 1:
     *** WE ROLL BACK TRANSACTION (1)
     ------------
     TRANSACTIONS
     ------------
     Trx id counter 0 290328385
     Purge done for trx's n:o < 0 290315608 undo n:o < 0 17
     History list length 20
     Total number of lock structs in row lock hash table 70
     LIST OF TRANSACTIONS FOR EACH SESSION:
     ---TRANSACTION 0 0, not started, process no 3491, OS thread id 42002
     MySQL thread id 32, query id 4668737 localhost heikki
     show innodb status
     ---TRANSACTION 0 290328384, ACTIVE 0 sec, process no 3205, OS thread id
     38929 inserting
     1 lock struct(s), heap size 320
     MySQL thread id 29, query id 4668736 localhost heikki update
     insert into speedc values (1519229,1, 'hgjhjgghggjgjgjgjgjggjgjgjgjgjgggjgjg
     jlhhgghggggghhjhghgggggghjhghghghghghhhhghghghjhhjghjghjkghjghjghjghjfhjfh
     ---TRANSACTION 0 290328383, ACTIVE 0 sec, process no 3180, OS thread id
     28684 committing
     1 lock struct(s), heap size 320, undo log entries 1
     MySQL thread id 19, query id 4668734 localhost heikki update
     insert into speedcm values (1603393,1, 'hgjhjgghggjgjgjgjgjggjgjgjgjgjgggjgj
     gjlhhgghggggghhjhghgggggghjhghghghghghhhhghghghjhhjghjghjkghjghjghjghjfhjf
     ---TRANSACTION 0 290328327, ACTIVE 0 sec, process no 3200, OS thread id
     36880 starting index read
     LOCK WAIT 2 lock struct(s), heap size 320
     MySQL thread id 27, query id 4668644 localhost heikki Searching rows for
     update
     update ibtest11a set B = 'kHdkkkk' where A = 89572
     ------- TRX HAS BEEN WAITING 0 SEC FOR THIS LOCK TO BE GRANTED:
     RECORD LOCKS space id 0 page no 65556 n bits 232 table test/ibtest11a index
     PRIMARY trx id 0 290328327 lock_mode X waiting
     Record lock, heap no 1 RECORD: info bits 0 0: len 9; hex 73757072656d756d00;
     asc supremum.;;
     ------------------
     ---TRANSACTION 0 290328284, ACTIVE 0 sec, process no 3195, OS thread id
     34831 rollback of SQL statement
     ROLLING BACK 14 lock struct(s), heap size 2496, undo log entries 9
     MySQL thread id 25, query id 4668733 localhost heikki update
     insert into ibtest11a (D, B, C) values (5, 'khDk' ,'khDk')
     ---TRANSACTION 0 290327208, ACTIVE 1 sec, process no 3190, OS thread id
     32782
     58 lock struct(s), heap size 5504, undo log entries 159
     MySQL thread id 23, query id 4668732 localhost heikki update
     REPLACE INTO alex1 VALUES(86, 46, 538,'aa95666','bb','c95666','d9486t',
     'e200498f','g86814','h538',date_format('2001-04-03 12:54:22','%Y-%m-%d
     %H:%i'),
     ---TRANSACTION 0 290323325, ACTIVE 3 sec, process no 3185, OS thread id
     30733 inserting
     4 lock struct(s), heap size 1024, undo log entries 165
     MySQL thread id 21, query id 4668735 localhost heikki update
     INSERT INTO alex1 VALUES(NULL, 49, NULL,'aa42837','','c56319','d1719t','',
     NULL,'h321', NULL, NULL, 7.31,7.31,7.31,200)
     --------
     FILE I/O
     --------
     I/O thread 0 state: waiting for i/o request (insert buffer thread)
     I/O thread 1 state: waiting for i/o request (log thread)
     I/O thread 2 state: waiting for i/o request (read thread)
     I/O thread 3 state: waiting for i/o request (write thread)
     Pending normal aio reads: 0, aio writes: 0,
      ibuf aio reads: 0, log i/o's: 0, sync i/o's: 0
     Pending flushes (fsync) log: 0; buffer pool: 0
     151671 OS file reads, 94747 OS file writes, 8750 OS fsyncs
     25.44 reads/s, 18494 avg bytes/read, 17.55 writes/s, 2.33 fsyncs/s
     -------------------------------------
     INSERT BUFFER AND ADAPTIVE HASH INDEX
     -------------------------------------
     Ibuf for space 0: size 1, free list len 19, seg size 21,
     85004 inserts, 85004 merged recs, 26669 merges
     Hash table size 207619, used cells 14461, node heap has 16 buffer(s)
     1877.67 hash searches/s, 5121.10 non-hash searches/s
     ---
     LOG
     ---
     Log sequence number 18 1212842764
     Log flushed up to   18 1212665295
     Last checkpoint at  18 1135877290
     0 pending log writes, 0 pending chkp writes
     4341 log i/o's done, 1.22 log i/o's/second
     ----------------------
     BUFFER POOL AND MEMORY
     ----------------------
     Total memory allocated 84966343; in additional pool allocated 1402624
     Buffer pool size   3200
     Free buffers       110
     Database pages     3074
     Modified db pages  2674
     Pending reads 0
     Pending writes: LRU 0, flush list 0, single page 0
     Pages read 171380, created 51968, written 194688
     28.72 reads/s, 20.72 creates/s, 47.55 writes/s
     Buffer pool hit rate 999 / 1000
     --------------
     ROW OPERATIONS
     --------------
     0 queries inside InnoDB, 0 queries in queue
     Main thread process no. 3004, id 7176, state: purging
     Number of rows inserted 3738558, updated 127415, deleted 33707, read 755779
     1586.13 inserts/s, 50.89 updates/s, 28.44 deletes/s, 107.88 reads/s
     ----------------------------
     END OF INNODB MONITOR OUTPUT
     ============================

`InnoDB' Monitor output is limited to 64,000 bytes when produced using
the *Note `SHOW ENGINE INNODB STATUS': show-engine. statement. This
limit does not apply to output written to the server's error output.

Some notes on the output sections:

*`SEMAPHORES'*

This section reports threads waiting for a semaphore and statistics on
how many times threads have needed a spin or a wait on a mutex or a
rw-lock semaphore. A large number of threads waiting for semaphores may
be a result of disk I/O, or contention problems inside `InnoDB'.
Contention can be due to heavy parallelism of queries or problems in
operating system thread scheduling. Setting the
`innodb_thread_concurrency' system variable smaller than the default
value might help in such situations.

*`LATEST FOREIGN KEY ERROR'*

This section provides information about the most recent foreign key
constraint error. It is not present if no such error has occurred. The
contents include the statement that failed as well as information about
the constraint that failed and the referenced and referencing tables.

*`LATEST DETECTED DEADLOCK'*

This section provides information about the most recent deadlock. It is
not present if no deadlock has occurred. The contents show which
transactions are involved, the statement each was attempting to
execute, the locks they have and need, and which transaction `InnoDB'
decided to roll back to break the deadlock. The lock modes reported in
this section are explained in *Note innodb-lock-modes::.

*`TRANSACTIONS'*

If this section reports lock waits, your applications might have lock
contention. The output can also help to trace the reasons for
transaction deadlocks.

*`FILE I/O'*

This section provides information about threads that `InnoDB' uses to
perform various types of I/O. The first few of these are dedicated to
general `InnoDB' processing. The contents also display information for
pending I/O operations and statistics for I/O performance.

On Unix, the number of threads is always 4. On Windows, the number
depends on the setting of the `innodb_file_io_threads' system variable.

*`INSERT BUFFER AND ADAPTIVE HASH INDEX'*

This section shows the status of the `InnoDB' insert buffer and
adaptive hash index. (See *Note innodb-insert-buffering::, and *Note
innodb-adaptive-hash::.) The contents include the number of operations
performed for each, plus statistics for hash index performance.

*`LOG'*

This section displays information about the `InnoDB' log. The contents
include the current log sequence number, how far the log has been
flushed to disk, and the position at which `InnoDB' last took a
checkpoint. (See *Note innodb-checkpoints::.) The section also displays
information about pending writes and write performance statistics.

*`BUFFER POOL AND MEMORY'*

This section gives you statistics on pages read and written.  You can
calculate from these numbers how many data file I/O operations your
queries currently are doing.

For additional information about the operation of the buffer pool, see
*Note innodb-buffer-pool::.

*`ROW OPERATIONS'*

This section shows what the main thread is doing, including the number
and performance rate for each type of row operation.


File: manual.info,  Node: innodb-tablespace-monitor,  Next: innodb-table-monitor,  Prev: innodb-standard-monitor,  Up: innodb-monitors

14.2.13.4 `InnoDB' Tablespace Monitor Output
............................................

The `InnoDB' Tablespace Monitor prints information about the file
segments in the shared tablespace and validates the tablespace
allocation data structures. If you use individual tablespaces by
enabling `innodb_file_per_table', the Tablespace Monitor does not
describe those tablespaces.

Example `InnoDB' Tablespace Monitor output:

     ================================================
     090408 21:28:09 INNODB TABLESPACE MONITOR OUTPUT
     ================================================
     FILE SPACE INFO: id 0
     size 13440, free limit 3136, free extents 28
     not full frag extents 2: used pages 78, full frag extents 3
     first seg id not used 0 23845
     SEGMENT id 0 1 space 0; page 2; res 96 used 46; full ext 0
     fragm pages 32; free extents 0; not full extents 1: pages 14
     SEGMENT id 0 2 space 0; page 2; res 1 used 1; full ext 0
     fragm pages 1; free extents 0; not full extents 0: pages 0
     SEGMENT id 0 3 space 0; page 2; res 1 used 1; full ext 0
     fragm pages 1; free extents 0; not full extents 0: pages 0
     ...
     SEGMENT id 0 15 space 0; page 2; res 160 used 160; full ext 2
     fragm pages 32; free extents 0; not full extents 0: pages 0
     SEGMENT id 0 488 space 0; page 2; res 1 used 1; full ext 0
     fragm pages 1; free extents 0; not full extents 0: pages 0
     SEGMENT id 0 17 space 0; page 2; res 1 used 1; full ext 0
     fragm pages 1; free extents 0; not full extents 0: pages 0
     ...
     SEGMENT id 0 171 space 0; page 2; res 592 used 481; full ext 7
     fragm pages 16; free extents 0; not full extents 2: pages 17
     SEGMENT id 0 172 space 0; page 2; res 1 used 1; full ext 0
     fragm pages 1; free extents 0; not full extents 0: pages 0
     SEGMENT id 0 173 space 0; page 2; res 96 used 44; full ext 0
     fragm pages 32; free extents 0; not full extents 1: pages 12
     ...
     SEGMENT id 0 601 space 0; page 2; res 1 used 1; full ext 0
     fragm pages 1; free extents 0; not full extents 0: pages 0
     NUMBER of file segments: 73
     Validating tablespace
     Validation ok
     ---------------------------------------
     END OF INNODB TABLESPACE MONITOR OUTPUT
     =======================================

The Tablespace Monitor output includes information about the shared
tablespace as a whole, followed by a list containing a breakdown for
each segment within the tablespace.

The tablespace consists of database pages with a default size of 16KB.
The pages are grouped into extents of size 1MB (64 consecutive pages).

The initial part of the output that displays overall tablespace
information has this format:

     FILE SPACE INFO: id 0
     size 13440, free limit 3136, free extents 28
     not full frag extents 2: used pages 78, full frag extents 3
     first seg id not used 0 23845

Overall tablespace information includes these values:

   * `id': The tablespace ID. A value of 0 refers to the shared
     tablespace.

   * `size': The current tablespace size in pages.

   * `free limit': The minimum page number for which the free list has
     not been initialized. Pages at or above this limit are free.

   * `free extents': The number of free extents.

   * `not full frag extents', `used pages': The number of fragment
     extents that are not completely filled, and the number of pages in
     those extents that have been allocated.

   * `full frag extents': The number of completely full fragment
     extents.

   * `first seg id not used': The first unused segment ID.

Individual segment information has this format:

     SEGMENT id 0 15 space 0; page 2; res 160 used 160; full ext 2
     fragm pages 32; free extents 0; not full extents 0: pages 0

Segment information includes these values:

`id': The segment ID.

`space', `page': The tablespace number and page within the tablespace
where the segment `inode' is located. A tablespace number of 0
indicates the shared tablespace.  `InnoDB' uses inodes to keep track of
segments in the tablespace. The other fields displayed for a segment
(`id', `res', and so forth) are derived from information in the inode.

`res': The number of pages allocated (reserved) for the segment.

`used': The number of allocated pages in use by the segment.

`full ext': The number of extents allocated for the segment that are
completely used.

`fragm pages': The number of initial pages that have been allocated to
the segment.

`free extents': The number of extents allocated for the segment that
are completely unused.

`not full extents': The number of extents allocated for the segment
that are partially used.

`pages': The number of pages used within the not-full extents.

When a segment grows, it starts as a single page, and `InnoDB'
allocates the first pages for it individually, up to 32 pages (this is
the `fragm pages' value). After that, `InnoDB' allocates complete
64-page extents. `InnoDB' can add up to 4 extents at a time to a large
segment to ensure good sequentiality of data.

For the example segment shown earlier, it has 32 fragment pages, plus 2
full extents (64 pages each), for a total of 160 pages used out of 160
pages allocated. The following segment has 32 fragment pages and one
partially full extent using 14 pages for a total of 46 pages used out
of 96 pages allocated:

     SEGMENT id 0 1 space 0; page 2; res 96 used 46; full ext 0
     fragm pages 32; free extents 0; not full extents 1: pages 14

It is possible for a segment that has extents allocated to it to have a
`fragm pages' value less than 32 if some of the individual pages have
been deallocated subsequent to extent allocation.


File: manual.info,  Node: innodb-table-monitor,  Prev: innodb-tablespace-monitor,  Up: innodb-monitors

14.2.13.5 `InnoDB' Table Monitor Output
.......................................

The `InnoDB' Table Monitor prints the contents of the `InnoDB' internal
data dictionary.

The output contains one section per table. The `SYS_FOREIGN' and
`SYS_FOREIGN_COLS' sections are for internal data dictionary tables
that maintain information about foreign keys. There are also sections
for the Table Monitor table and each user-created `InnoDB' table.
Suppose that the following two tables have been created in the `test'
database:

     CREATE TABLE parent
     (
       par_id    INT NOT NULL,
       fname      CHAR(20),
       lname      CHAR(20),
       PRIMARY KEY (par_id),
       UNIQUE INDEX (lname, fname)
     ) ENGINE = INNODB;

     CREATE TABLE child
     (
       par_id      INT NOT NULL,
       child_id    INT NOT NULL,
       name        VARCHAR(40),
       birth       DATE,
       weight      DECIMAL(10,2),
       misc_info   VARCHAR(255),
       last_update TIMESTAMP,
       PRIMARY KEY (par_id, child_id),
       INDEX (name),
       FOREIGN KEY (par_id) REFERENCES parent (par_id)
         ON DELETE CASCADE
         ON UPDATE CASCADE
     ) ENGINE = INNODB;

Then the Table Monitor output will look something like this
(reformatted slightly):

     ===========================================
     090420 12:05:26 INNODB TABLE MONITOR OUTPUT
     ===========================================
     --------------------------------------
     TABLE: name SYS_FOREIGN, id 0 11, columns 8, indexes 3, appr.rows 1
       COLUMNS: ID: DATA_VARCHAR DATA_ENGLISH len 0 prec 0;
                FOR_NAME: DATA_VARCHAR DATA_ENGLISH len 0 prec 0;
                REF_NAME: DATA_VARCHAR DATA_ENGLISH len 0 prec 0;
                N_COLS: DATA_INT len 4 prec 0;
                DB_ROW_ID: DATA_SYS prtype 256 len 6 prec 0;
                DB_TRX_ID: DATA_SYS prtype 257 len 6 prec 0;
                DB_ROLL_PTR: DATA_SYS prtype 258 len 7 prec 0;
       INDEX: name ID_IND, id 0 11, fields 1/6, type 3
        root page 46, appr.key vals 1, leaf pages 1, size pages 1
        FIELDS:  ID DB_TRX_ID DB_ROLL_PTR FOR_NAME REF_NAME N_COLS
       INDEX: name FOR_IND, id 0 12, fields 1/2, type 0
        root page 47, appr.key vals 1, leaf pages 1, size pages 1
        FIELDS:  FOR_NAME ID
       INDEX: name REF_IND, id 0 13, fields 1/2, type 0
        root page 48, appr.key vals 1, leaf pages 1, size pages 1
        FIELDS:  REF_NAME ID
     --------------------------------------
     TABLE: name SYS_FOREIGN_COLS, id 0 12, columns 8, indexes 1, appr.rows 1
       COLUMNS: ID: DATA_VARCHAR DATA_ENGLISH len 0 prec 0;
                POS: DATA_INT len 4 prec 0;
                FOR_COL_NAME: DATA_VARCHAR DATA_ENGLISH len 0 prec 0;
                REF_COL_NAME: DATA_VARCHAR DATA_ENGLISH len 0 prec 0;
                DB_ROW_ID: DATA_SYS prtype 256 len 6 prec 0;
                DB_TRX_ID: DATA_SYS prtype 257 len 6 prec 0;
                DB_ROLL_PTR: DATA_SYS prtype 258 len 7 prec 0;
       INDEX: name ID_IND, id 0 14, fields 2/6, type 3
        root page 49, appr.key vals 1, leaf pages 1, size pages 1
        FIELDS:  ID POS DB_TRX_ID DB_ROLL_PTR FOR_COL_NAME REF_COL_NAME
     --------------------------------------
     TABLE: name test/child, id 0 14, columns 11, indexes 2, appr.rows 210
       COLUMNS: par_id: DATA_INT len 4 prec 0;
                child_id: DATA_INT len 4 prec 0;
                name: DATA_VARCHAR prtype 524303 len 40 prec 0;
                birth: DATA_INT len 3 prec 0;
                weight: type 3 len 5 prec 0;
                misc_info: DATA_VARCHAR prtype 524303 len 255 prec 0;
                last_update: DATA_INT len 4 prec 0;
                DB_ROW_ID: DATA_SYS prtype 256 len 6 prec 0;
                DB_TRX_ID: DATA_SYS prtype 257 len 6 prec 0;
                DB_ROLL_PTR: DATA_SYS prtype 258 len 7 prec 0;
       INDEX: name PRIMARY, id 0 17, fields 2/9, type 3
        root page 52, appr.key vals 210, leaf pages 1, size pages 1
        FIELDS:  par_id child_id DB_TRX_ID DB_ROLL_PTR name birth weight misc_info last_update
       INDEX: name name, id 0 18, fields 1/3, type 0
        root page 53, appr.key vals 1, leaf pages 1, size pages 1
        FIELDS:  name par_id child_id
       FOREIGN KEY CONSTRAINT test/child_ibfk_1: test/child ( par_id )
                  REFERENCES test/parent ( par_id )
     --------------------------------------
     TABLE: name test/innodb_table_monitor, id 0 15, columns 5, indexes 1, appr.rows 0
       COLUMNS: i: DATA_INT len 4 prec 0;
                DB_ROW_ID: DATA_SYS prtype 256 len 6 prec 0;
                DB_TRX_ID: DATA_SYS prtype 257 len 6 prec 0;
                DB_ROLL_PTR: DATA_SYS prtype 258 len 7 prec 0;
       INDEX: name GEN_CLUST_INDEX, id 0 19, fields 0/4, type 1
        root page 54, appr.key vals 0, leaf pages 1, size pages 1
        FIELDS:  DB_ROW_ID DB_TRX_ID DB_ROLL_PTR i
     --------------------------------------
     TABLE: name test/parent, id 0 13, columns 7, indexes 2, appr.rows 299
       COLUMNS: par_id: DATA_INT len 4 prec 0;
                fname: DATA_CHAR prtype 524542 len 20 prec 0;
                lname: DATA_CHAR prtype 524542 len 20 prec 0;
                DB_ROW_ID: DATA_SYS prtype 256 len 6 prec 0;
                DB_TRX_ID: DATA_SYS prtype 257 len 6 prec 0;
                DB_ROLL_PTR: DATA_SYS prtype 258 len 7 prec 0;
       INDEX: name PRIMARY, id 0 15, fields 1/5, type 3
        root page 50, appr.key vals 299, leaf pages 2, size pages 3
        FIELDS:  par_id DB_TRX_ID DB_ROLL_PTR fname lname
       INDEX: name lname, id 0 16, fields 2/3, type 2
        root page 51, appr.key vals 300, leaf pages 1, size pages 1
        FIELDS:  lname fname par_id
       FOREIGN KEY CONSTRAINT test/child_ibfk_1: test/child ( par_id )
                  REFERENCES test/parent ( par_id )
     -----------------------------------
     END OF INNODB TABLE MONITOR OUTPUT
     ==================================

For each table, Table Monitor output contains a section that displays
general information about the table and specific information about its
columns, indexes, and foreign keys.

The general information for each table includes the table name (in
`DB_NAME/TBL_NAME' format except for internal tables), its ID, the
number of columns and indexes, and an approximate row count.

The `COLUMNS' part of a table section lists each column in the table.
Information for each column indicates its name and data type
characteristics. Some internal columns are added by `InnoDB', such as
`DB_ROW_ID' (row ID), `DB_TRX_ID' (transaction ID), and `DB_ROLL_PTR'
(a pointer to the rollback/undo data).

   * `DATA_XXX': These symbols indicate the data type. There may be
     multiple `DATA_XXX' symbols for a given column.

   * `prtype': The column's `precise' type. This field includes
     information such as the column data type, character set code,
     nullability, signedness, and whether it is a binary string. This
     field is described in the `innobase/include/data0type.h' source
     file.

   * `len': The column length in bytes.

   * `prec': The precision of the type.

Each `INDEX' part of the table section provides the name and
characteristics of one table index:

   * `name': The index name. If the name is `PRIMARY', the index is a
     primary key. If the name is `GEN_CLUST_INDEX', the index is the
     clustered index that is created automatically if the table
     definition doesn't include a primary key or non-`NULL' unique
     index. See *Note innodb-index-types::.

   * `id': The index ID.

   * `fields': The number of fields in the index, as a value in `M/N'
     format:

        * M is the number of user-defined columns; that is, the number
          of columns you would see in the index definition in a `CREATE
          TABLE' statement.

        * N is the total number of index columns, including those added
          internally. For the clustered index, the total includes the
          other columns in the table definition, plus any columns added
          internally. For a secondary index, the total includes the
          columns from the primary key that are not part of the
          secondary index.

   * `type': The index type. This is a bit field. For example, 1
     indicates a clustered index and 2 indicates a unique index, so a
     clustered index (which always contains unique values), will have a
     `type' value of 3. An index with a `type' value of 0 is neither
     clustered nor unique. The flag values are defined in the
     `innobase/include/dict0mem.h' source file.

   * `root page': The index root page number.

   * `appr. key vals': The approximate index cardinality.

   * `leaf pages': The approximate number of leaf pages in the index.

   * `size pages': The approximate total number of pages in the index.

   * `FIELDS': The names of the fields in the index. For a clustered
     index that was generated automatically, the field list begins with
     the internal `DB_ROW_ID' (row ID) field.  `DB_TRX_ID' and
     `DB_ROLL_PTR' are always added internally to the clustered index,
     following the fields that comprise the primary key. For a
     secondary index, the final fields are those from the primary key
     that are not part of the secondary index.

The end of the table section lists the `FOREIGN KEY' definitions that
apply to the table. This information appears whether the table is a
referencing or referenced table.


File: manual.info,  Node: innodb-troubleshooting,  Next: innodb-troubleshooting-datadict,  Prev: innodb-monitors,  Up: innodb-tuning-troubleshooting

14.2.13.6 `InnoDB' General Troubleshooting
..........................................

The following general guidelines apply to troubleshooting `InnoDB'
problems:

   * When an operation fails or you suspect a bug, you should look at
     the MySQL server error log (see *Note error-log::).

   * Issues relating to the `InnoDB' data dictionary include failed
     *Note `CREATE TABLE': create-table. statements (orphaned table
     files), inability to open `.InnoDB' files, and `system cannot find
     the path specified' errors. For information about these sorts of
     problems and errors, see *Note innodb-troubleshooting-datadict::.

   * When troubleshooting, it is usually best to run the MySQL server
     from the command prompt, rather than through *Note `mysqld_safe':
     mysqld-safe. or as a Windows service. You can then see what *Note
     `mysqld': mysqld. prints to the console, and so have a better
     grasp of what is going on. On Windows, start *Note `mysqld':
     mysqld. with the `--console' option to direct the output to the
     console window.

   * Use the `InnoDB' Monitors to obtain information about a problem
     (see *Note innodb-monitors::). If the problem is
     performance-related, or your server appears to be hung, you should
     use the standard Monitor to print information about the internal
     state of `InnoDB'. If the problem is with locks, use the Lock
     Monitor. If the problem is in creation of tables or other data
     dictionary operations, use the Table Monitor to print the contents
     of the `InnoDB' internal data dictionary. To see tablespace
     information use the Tablespace Monitor.

   * If you suspect that a table is corrupt, run *Note `CHECK TABLE':
     check-table. on that table.


File: manual.info,  Node: innodb-troubleshooting-datadict,  Prev: innodb-troubleshooting,  Up: innodb-tuning-troubleshooting

14.2.13.7 Troubleshooting `InnoDB' Data Dictionary Operations
.............................................................

A specific issue with tables is that the MySQL server keeps data
dictionary information in `.frm' files it stores in the database
directories, whereas `InnoDB' also stores the information into its own
data dictionary inside the tablespace files. If you move `.frm' files
around, or if the server crashes in the middle of a data dictionary
operation, the locations of the `.frm' files may end up out of synchrony
with the locations recorded in the `InnoDB' internal data dictionary.

A symptom of an out-of-sync data dictionary is that a *Note `CREATE
TABLE': create-table. statement fails. If this occurs, you should look
in the server's error log. If the log says that the table already
exists inside the `InnoDB' internal data dictionary, you have an
orphaned table inside the `InnoDB' tablespace files that has no
corresponding `.frm' file.  The error message looks like this:

     InnoDB: Error: table test/parent already exists in InnoDB internal
     InnoDB: data dictionary. Have you deleted the .frm file
     InnoDB: and not used DROP TABLE? Have you used DROP DATABASE
     InnoDB: for InnoDB tables in MySQL version <= 3.23.43?
     InnoDB: See the Restrictions section of the InnoDB manual.
     InnoDB: You can drop the orphaned table inside InnoDB by
     InnoDB: creating an InnoDB table with the same name in another
     InnoDB: database and moving the .frm file to the current database.
     InnoDB: Then MySQL thinks the table exists, and DROP TABLE will
     InnoDB: succeed.

You can drop the orphaned table by following the instructions given in
the error message. If you are still unable to use *Note `DROP TABLE':
drop-table. successfully, the problem may be due to name completion in
the *Note `mysql': mysql. client. To work around this problem, start
the *Note `mysql': mysql. client with the `--skip-auto-rehash' option
and try *Note `DROP TABLE': drop-table. again.  (With name completion
on, *Note `mysql': mysql. tries to construct a list of table names,
which fails when a problem such as just described exists.)

Another symptom of an out-of-sync data dictionary is that MySQL prints
an error that it cannot open a `.InnoDB' file:

     ERROR 1016: Can't open file: 'child2.InnoDB'. (errno: 1)

In the error log you can find a message like this:

     InnoDB: Cannot find table test/child2 from the internal data dictionary
     InnoDB: of InnoDB though the .frm file for the table exists. Maybe you
     InnoDB: have deleted and recreated InnoDB data files but have forgotten
     InnoDB: to delete the corresponding .frm files of InnoDB tables?

This means that there is an orphaned `.frm' file without a
corresponding table inside `InnoDB'. You can drop the orphaned `.frm'
file by deleting it manually.

If MySQL crashes in the middle of an *Note `ALTER TABLE': alter-table.
operation, you may end up with an orphaned temporary table inside the
`InnoDB' tablespace.  Using the Table Monitor, you can see listed a
table with a name that begins with `#sql-'. You can perform SQL
statements on tables whose name contains the character ``#'' if you
enclose the name within backticks. Thus, you can drop such an orphaned
table like any other orphaned table using the method described earlier.
To copy or rename a file in the Unix shell, you need to put the file
name in double quotation marks if the file name contains ``#''.

With `innodb_file_per_table' enabled, the following message might occur
if the `.frm' or `.ibd' files (or both) are missing:

     InnoDB: in InnoDB data dictionary has tablespace id N,
     InnoDB: but tablespace with that id or name does not exist. Have
     InnoDB: you deleted or moved .ibd files?
     InnoDB: This may also be a table created with CREATE TEMPORARY TABLE
     InnoDB: whose .ibd and .frm files MySQL automatically removed, but the
     InnoDB: table still exists in the InnoDB internal data dictionary.

If this occurs, try the following procedure to resolve the problem:

  1. Create a matching `.frm' file in some other database directory and
     copy it to the database directory where the orphan table is
     located.

  2. Issue *Note `DROP TABLE': drop-table. for the original table. That
     should successfully drop the table and `InnoDB' should print a
     warning to the error log that the `.ibd' file was missing.


File: manual.info,  Node: innodb-restrictions,  Prev: innodb-tuning-troubleshooting,  Up: innodb-storage-engine

14.2.14 Limits on `InnoDB' Tables
---------------------------------

*Warning*:

Do _not_ convert MySQL system tables in the `mysql' database from
`MyISAM' to `InnoDB' tables! This is an unsupported operation. If you
do this, MySQL does not restart until you restore the old system tables
from a backup or re-generate them with the *Note `mysql_install_db':
mysql-install-db. script.

*Warning*:

It is not a good idea to configure `InnoDB' to use data files or log
files on NFS volumes. Otherwise, the files might be locked by other
processes and become unavailable for use by MySQL.

* Maximums and Minimums *

   * A table can contain up to 1000 columns.

   * The `InnoDB' internal maximum key length is 3500 bytes, but MySQL
     itself restricts this to 3072 bytes.  (1024 bytes for non-64-bit
     builds before MySQL 5.0.17, and for all builds before 5.0.15.)

   * Index key prefixes can be up to 767 bytes. See *Note
     create-index::.

   * The maximum row length, except for variable-length columns (*Note
     `VARBINARY': binary-varbinary, *Note `VARCHAR': char, *Note
     `BLOB': blob. and *Note `TEXT': blob.), is slightly less than half
     of a database page. That is, the maximum row length is about 8000
     bytes. *Note `LONGBLOB': blob. and *Note `LONGTEXT': blob.
     columns must be less than 4GB, and the total row length, including
     *Note `BLOB': blob. and *Note `TEXT': blob. columns, must be less
     than 4GB.

     If a row is less than half a page long, all of it is stored
     locally within the page. If it exceeds half a page,
     variable-length columns are chosen for external off-page storage
     until the row fits within half a page, as described in *Note
     innodb-file-space::.

   * Although `InnoDB' supports row sizes larger than 65,535 bytes
     internally, MySQL inself imposes a row-size limit of 65,535 for
     the combined size of all columns:


          mysql> CREATE TABLE t (a VARCHAR(8000), b VARCHAR(10000),
              -> c VARCHAR(10000), d VARCHAR(10000), e VARCHAR(10000),
              -> f VARCHAR(10000), g VARCHAR(10000)) ENGINE=InnoDB;
          ERROR 1118 (42000): Row size too large. The maximum row size for the
          used table type, not counting BLOBs, is 65535. You have to change some
          columns to TEXT or BLOBs

     See *Note column-count-limit::.

   * On some older operating systems, files must be less than 2GB.
     This is not a limitation of `InnoDB' itself, but if you require a
     large tablespace, you will need to configure it using several
     smaller data files rather than one or a file large data files.

   * The combined size of the `InnoDB' log files must be less than 4GB.

   * The minimum tablespace size is 10MB. The maximum tablespace size
     is four billion database pages (64TB). This is also the maximum
     size for a table.

   * The default database page size in `InnoDB' is 16KB. By recompiling
     the code, you can set it to values ranging from 8KB to 64KB. You
     must update the values of `UNIV_PAGE_SIZE' and
     `UNIV_PAGE_SIZE_SHIFT' in the `univ.i' source file.

     *Note*:

     Changing the page size is not a supported operation and there is
     no guarantee that *Note `InnoDB': innodb-storage-engine. will
     function normally with a page size other than 16KB. Problems
     compiling or running InnoDB may occur.

     A version of *Note `InnoDB': innodb-storage-engine. built for one
     page size cannot use data files or log files from a version built
     for a different page size.

* Index Types *

   * `InnoDB' tables do not support `FULLTEXT' indexes.

   * `InnoDB' tables do not support spatial data types before MySQL
     5.0.16. As of 5.0.16, `InnoDB' supports spatial data types, but not
     indexes on them.

* Restrictions on InnoDB Tables *

   * *Note `ANALYZE TABLE': analyze-table. determines index cardinality
     (as displayed in the `Cardinality' column of *Note `SHOW INDEX':
     show-index. output) by doing eight random dives to each of the
     index trees and updating index cardinality estimates accordingly.
     Because these are only estimates, repeated runs of *Note `ANALYZE
     TABLE': analyze-table. may produce different numbers. This makes
     *Note `ANALYZE TABLE': analyze-table. fast on `InnoDB' tables but
     not 100% accurate because it does not take all rows into account.

     MySQL uses index cardinality estimates only in join optimization.
     If some join is not optimized in the right way, you can try using
     *Note `ANALYZE TABLE': analyze-table. In the few cases that *Note
     `ANALYZE TABLE': analyze-table. does not produce values good
     enough for your particular tables, you can use `FORCE INDEX' with
     your queries to force the use of a particular index, or set the
     `max_seeks_for_key' system variable to ensure that MySQL prefers
     index lookups over table scans. See *Note
     server-system-variables::, and *Note optimizer-issues::.

   * *Note `SHOW TABLE STATUS': show-table-status. does not give
     accurate statistics on `InnoDB' tables, except for the physical
     size reserved by the table. The row count is only a rough estimate
     used in SQL optimization.

   * `InnoDB' does not keep an internal count of rows in a table
     because concurrent transactions might `see' different numbers of
     rows at the same time.  To process a `SELECT COUNT(*) FROM t'
     statement, `InnoDB' must scan an index of the table, which takes
     some time if the index is not entirely in the buffer pool. If your
     table does not change often, using the MySQL query cache is a good
     solution. To get a fast count, you have to use a counter table you
     create yourself and let your application update it according to
     the inserts and deletes it does. If an approximate row count is
     sufficient, *Note `SHOW TABLE STATUS': show-table-status. can be
     used.  See *Note innodb-tuning::.

   * On Windows, `InnoDB' always stores database and table names
     internally in lowercase. To move databases in a binary format from
     Unix to Windows or from Windows to Unix, create all databases and
     tables using lowercase names.

   * For an `AUTO_INCREMENT' column, you must always define an index
     for the table, and that index must contain just the
     `AUTO_INCREMENT' column. In `MyISAM' tables, the `AUTO_INCREMENT'
     column may be part of a multiple-column index.

   * In MySQL 5.0 before MySQL 5.0.3, `InnoDB' does not support the
     `AUTO_INCREMENT' table option for setting the initial sequence
     value in a *Note `CREATE TABLE': create-table. or *Note `ALTER
     TABLE': alter-table.  statement. To set the value with `InnoDB',
     insert a dummy row with a value one less and delete that dummy
     row, or insert the first row with an explicit value specified.

   * While initializing a previously specified `AUTO_INCREMENT' column
     on a table, `InnoDB' sets an exclusive lock on the end of the
     index associated with the `AUTO_INCREMENT' column. While accessing
     the auto-increment counter, `InnoDB' uses a specific `AUTO-INC'
     table lock mode where the lock lasts only to the end of the
     current SQL statement, not to the end of the entire transaction.
     Other clients cannot insert into the table while the `AUTO-INC'
     table lock is held. See *Note innodb-auto-increment-handling::.

   * When you restart the MySQL server, `InnoDB' may reuse an old value
     that was generated for an `AUTO_INCREMENT' column but never stored
     (that is, a value that was generated during an old transaction
     that was rolled back).

   * When an `AUTO_INCREMENT' column runs out of values, `InnoDB' wraps
     a *Note `BIGINT': numeric-types. to `-9223372036854775808' and
     `BIGINT UNSIGNED' to `1'. However, *Note `BIGINT': numeric-types.
     values have 64 bits, so if you were to insert one million rows per
     second, it would still take nearly three hundred thousand years
     before *Note `BIGINT': numeric-types. reached its upper bound.
     With all other integer type columns, a duplicate-key error
     results. This is general MySQL behavior, similar to how `MyISAM'
     works.

   * `DELETE FROM TBL_NAME' does not regenerate the table but instead
     deletes all rows, one by one.

   * Under some conditions, `TRUNCATE TBL_NAME' for an `InnoDB' table
     is mapped to `DELETE FROM TBL_NAME' and does not reset the
     `AUTO_INCREMENT' counter. See *Note truncate-table::.

   * The *Note `LOAD TABLE FROM MASTER': load-table-from-master.
     statement for setting up replication slave servers does not work
     for `InnoDB' tables. A workaround is to alter the table to
     `MyISAM' on the master, then do the load, and after that alter the
     master table back to `InnoDB'. Do not do this if the tables use
     `InnoDB'-specific features such as foreign keys.

   * Currently, cascaded foreign key actions do not activate triggers.

   * You cannot create a table with a column name that matches the name
     of an internal InnoDB column (including `DB_ROW_ID', `DB_TRX_ID',
     `DB_ROLL_PTR', and `DB_MIX_ID'). In versions of MySQL before
     5.0.21 this would cause a crash, since 5.0.21 the server will
     report error 1005 and refers to error -1 in the error message.
     This restriction applies only to use of the names in uppercase.

   * As of MySQL 5.0.19, `InnoDB' does not ignore trailing spaces when
     comparing *Note `BINARY': binary-varbinary. or *Note `VARBINARY':
     binary-varbinary. column values. See *Note binary-varbinary:: and
     *Note news-5-0-19::.

* Locking and Transactions *

   * *Note `LOCK TABLES': lock-tables. acquires two locks on each table
     if `innodb_table_locks=1' (the default). In addition to a table
     lock on the MySQL layer, it also acquires an `InnoDB' table lock.
     Versions of MySQL before 4.1.2 did not acquire `InnoDB' table
     locks; the old behavior can be selected by setting
     `innodb_table_locks=0'.  If no `InnoDB' table lock is acquired,
     *Note `LOCK TABLES': lock-tables. completes even if some records
     of the tables are being locked by other transactions.

   * All `InnoDB' locks held by a transaction are released when the
     transaction is committed or aborted. Thus, it does not make much
     sense to invoke *Note `LOCK TABLES': lock-tables. on `InnoDB'
     tables in `autocommit=1' mode because the acquired `InnoDB' table
     locks would be released immediately.

   * You cannot lock additional tables in the middle of a transaction
     because *Note `LOCK TABLES': lock-tables.  performs an implicit
     *Note `COMMIT': commit. and *Note `UNLOCK TABLES': lock-tables.

   * `InnoDB' has a limit of 1023 concurrent transactions that have
     created undo records by modifying data.  Workarounds include
     keeping transactions as small and fast as possible, delaying
     changes until near the end of the transaction, and using stored
     routines to reduce client/server latency delays. Applications
     should commit transactions before doing time-consuming client-side
     operations.


File: manual.info,  Node: merge-storage-engine,  Next: memory-storage-engine,  Prev: innodb-storage-engine,  Up: storage-engines

14.3 The `MERGE' Storage Engine
===============================

* Menu:

* merge-table-advantages::       `MERGE' Table Advantages and Disadvantages
* merge-table-problems::         `MERGE' Table Problems

The `MERGE' storage engine, also known as the `MRG_MyISAM' engine, is a
collection of identical `MyISAM' tables that can be used as one.
`Identical' means that all tables have identical column and index
information. You cannot merge `MyISAM' tables in which the columns are
listed in a different order, do not have exactly the same columns, or
have the indexes in different order. However, any or all of the
`MyISAM' tables can be compressed with *Note `myisampack': myisampack.
See *Note myisampack::. Differences in table options such as
`AVG_ROW_LENGTH', `MAX_ROWS', or `PACK_KEYS' do not matter.

When you create a `MERGE' table, MySQL creates two files on disk. The
files have names that begin with the table name and have an extension
to indicate the file type. An `.frm' file stores the table format, and
an `.MRG' file contains the names of the underlying `MyISAM' tables
that should be used as one. The tables do not have to be in the same
database as the `MERGE' table.

You can use *Note `SELECT': select, *Note `DELETE': delete, *Note
`UPDATE': update, and *Note `INSERT': insert. on `MERGE' tables. You
must have `SELECT', `DELETE', and `UPDATE' privileges on the `MyISAM'
tables that you map to a `MERGE' table.

*Note*:

The use of `MERGE' tables entails the following security issue: If a
user has access to `MyISAM' table T, that user can create a `MERGE'
table M that accesses T. However, if the user's privileges on T are
subsequently revoked, the user can continue to access T by doing so
through M. If this behavior is undesirable, you can start the server
with the new `--skip-merge' option to disable the `MERGE' storage
engine. This option is available as of MySQL 5.0.24.

Use of *Note `DROP TABLE': drop-table. with a `MERGE' table drops only
the `MERGE' specification. The underlying tables are not affected.

To create a `MERGE' table, you must specify a `UNION=(LIST-OF-TABLES)'
option that indicates which `MyISAM' tables to use.  You can optionally
specify an `INSERT_METHOD' option to control how inserts into the
`MERGE' table take place. Use a value of `FIRST' or `LAST' to cause
inserts to be made in the first or last underlying table, respectively.
If you specify no `INSERT_METHOD' option or if you specify it with a
value of `NO', inserts into the `MERGE' table are not permitted and
attempts to do so result in an error.

The following example shows how to create a `MERGE' table:

     mysql> CREATE TABLE t1 (
         ->    a INT NOT NULL AUTO_INCREMENT PRIMARY KEY,
         ->    message CHAR(20)) ENGINE=MyISAM;
     mysql> CREATE TABLE t2 (
         ->    a INT NOT NULL AUTO_INCREMENT PRIMARY KEY,
         ->    message CHAR(20)) ENGINE=MyISAM;
     mysql> INSERT INTO t1 (message) VALUES ('Testing'),('table'),('t1');
     mysql> INSERT INTO t2 (message) VALUES ('Testing'),('table'),('t2');
     mysql> CREATE TABLE total (
         ->    a INT NOT NULL AUTO_INCREMENT,
         ->    message CHAR(20), INDEX(a))
         ->    ENGINE=MERGE UNION=(t1,t2) INSERT_METHOD=LAST;

The older term `TYPE' is supported as a synonym for `ENGINE' for
backward compatibility, but `ENGINE' is the preferred term and `TYPE'
is deprecated.

Note that column `a' is indexed as a `PRIMARY KEY' in the underlying
`MyISAM' tables, but not in the `MERGE' table. There it is indexed but
not as a `PRIMARY KEY' because a `MERGE' table cannot enforce
uniqueness over the set of underlying tables.  (Similarly, a column
with a `UNIQUE' index in the underlying tables should be indexed in the
`MERGE' table but not as a `UNIQUE' index.)

After creating the `MERGE' table, you can use it to issue queries that
operate on the group of tables as a whole:

     mysql> SELECT * FROM total;
     +---+---------+
     | a | message |
     +---+---------+
     | 1 | Testing |
     | 2 | table   |
     | 3 | t1      |
     | 1 | Testing |
     | 2 | table   |
     | 3 | t2      |
     +---+---------+

To remap a `MERGE' table to a different collection of `MyISAM' tables,
you can use one of the following methods:

   * `DROP' the `MERGE' table and re-create it.

   * Use `ALTER TABLE TBL_NAME UNION=(...)' to change the list of
     underlying tables.

     Beginning with MySQL 5.0.60, it is also possible to use `ALTER
     TABLE ... UNION=()' (that is, with an empty *Note `UNION': union.
     clause) to remove all of the underlying tables.

As of MySQL 5.0.36, the underlying table definitions and indexes must
conform more closely than previously to the definition of the `MERGE'
table. Conformance is checked when a table that is part of a `MERGE'
table is opened, not when the `MERGE' table is created. If any table
fails the conformance checks, the operation that triggered the opening
of the table fails. This means that changes to the definitions of
tables within a `MERGE' may cause a failure when the `MERGE' table is
accessed. The conformance checks applied to each table are:

   * The underlying table and the `MERGE' table must have the same
     number of columns.

   * The column order in the underlying table and the `MERGE' table
     must match.

   * Additionally, the specification for each corresponding column in
     the parent `MERGE' table and the underlying tables are compared
     and must satisfy these checks:

        * The column type in the underlying table and the `MERGE' table
          must be equal.

        * The column length in the underlying table and the `MERGE'
          table must be equal.

        * The column of the underlying table and the `MERGE' table can
          be `NULL'.

   * The underlying table must have at least as many indexes as the
     `MERGE' table. The underlying table may have more indexes than the
     `MERGE' table, but cannot have fewer.

     *Note*:

     A known issue exists where indexes on the same columns must be in
     identical order, in both the `MERGE' table and the underlying
     `MyISAM' table. See Bug #33653.

     Each index must satisfy these checks:

        * The index type of the underlying table and the `MERGE' table
          must be the same.

        * The number of index parts (that is, multiple columns within a
          compound index) in the index definition for the underlying
          table and the `MERGE' table must be the same.

        * For each index part:

             * Index part lengths must be equal.

             * Index part types must be equal.

             * Index part languages must be equal.

             * Check whether index parts can be `NULL'.

For information about the table checks applied prior to MySQL 5.0.36,
see *Note merge-table-problems::.

As of MySQL 5.0.44, if a `MERGE' table cannot be opened or used because
of a problem with an underlying table, *Note `CHECK TABLE':
check-table. displays information about which table caused the problem.

* Additional Resources *

   * A forum dedicated to the `MERGE' storage engine is available at
     `http://forums.mysql.com/list.php?93'.


File: manual.info,  Node: merge-table-advantages,  Next: merge-table-problems,  Prev: merge-storage-engine,  Up: merge-storage-engine

14.3.1 `MERGE' Table Advantages and Disadvantages
-------------------------------------------------

`MERGE' tables can help you solve the following problems:

   * Easily manage a set of log tables. For example, you can put data
     from different months into separate tables, compress some of them
     with *Note `myisampack': myisampack, and then create a `MERGE'
     table to use them as one.

   * Obtain more speed. You can split a large read-only table based on
     some criteria, and then put individual tables on different disks.
     A `MERGE' table structured this way could be much faster than
     using a single large table.

   * Perform more efficient searches. If you know exactly what you are
     looking for, you can search in just one of the underlying tables
     for some queries and use a `MERGE' table for others. You can even
     have many different `MERGE' tables that use overlapping sets of
     tables.

   * Perform more efficient repairs. It is easier to repair individual
     smaller tables that are mapped to a `MERGE' table than to repair a
     single large table.

   * Instantly map many tables as one. A `MERGE' table need not
     maintain an index of its own because it uses the indexes of the
     individual tables. As a result, `MERGE' table collections are
     _very_ fast to create or remap. (You must still specify the index
     definitions when you create a `MERGE' table, even though no
     indexes are created.)

   * If you have a set of tables from which you create a large table on
     demand, you can instead create a `MERGE' table from them on
     demand. This is much faster and saves a lot of disk space.

   * Exceed the file size limit for the operating system. Each `MyISAM'
     table is bound by this limit, but a collection of `MyISAM' tables
     is not.

   * You can create an alias or synonym for a `MyISAM' table by
     defining a `MERGE' table that maps to that single table.  There
     should be no really notable performance impact from doing this
     (only a couple of indirect calls and `memcpy()' calls for each
     read).

The disadvantages of `MERGE' tables are:

   * You can use only identical `MyISAM' tables for a `MERGE' table.

   * Some `MyISAM' features are unavailable in `MERGE' tables. For
     example, you cannot create `FULLTEXT' indexes on `MERGE' tables.
     (You can create `FULLTEXT' indexes on the underlying `MyISAM'
     tables, but you cannot search the `MERGE' table with a full-text
     search.)

   * If the `MERGE' table is nontemporary, all underlying `MyISAM'
     tables must be nontemporary. If the `MERGE' table is temporary,
     the `MyISAM' tables can be any mix of temporary and nontemporary.

   * `MERGE' tables use more file descriptors than `MyISAM' tables. If
     10 clients are using a `MERGE' table that maps to 10 tables, the
     server uses (10 x 10) + 10 file descriptors. (10 data file
     descriptors for each of the 10 clients, and 10 index file
     descriptors shared among the clients.)

   * Index reads are slower. When you read an index, the `MERGE'
     storage engine needs to issue a read on all underlying tables to
     check which one most closely matches a given index value. To read
     the next index value, the `MERGE' storage engine needs to search
     the read buffers to find the next value. Only when one index
     buffer is used up does the storage engine need to read the next
     index block. This makes `MERGE' indexes much slower on `eq_ref'
     searches, but not much slower on `ref' searches. For more
     information about `eq_ref' and `ref', see *Note explain::.


File: manual.info,  Node: merge-table-problems,  Prev: merge-table-advantages,  Up: merge-storage-engine

14.3.2 `MERGE' Table Problems
-----------------------------

The following are known problems with `MERGE' tables:

   * If you use *Note `ALTER TABLE': alter-table. to change a `MERGE'
     table to another storage engine, the mapping to the underlying
     tables is lost. Instead, the rows from the underlying `MyISAM'
     tables are copied into the altered table, which then uses the
     specified storage engine.

   * The `INSERT_METHOD' table option for a `MERGE' table indicates
     which underlying `MyISAM' table to use for inserts into the
     `MERGE' table. However, use of the `AUTO_INCREMENT' table option
     for that `MyISAM' table has no effect for inserts into the `MERGE'
     table until at least one row has been inserted directly into the
     `MyISAM' table.

   * A `MERGE' table cannot maintain uniqueness constraints over the
     entire table. When you perform an *Note `INSERT': insert, the data
     goes into the first or last `MyISAM' table (as determined by the
     `INSERT_METHOD' option). MySQL ensures that unique key values
     remain unique within that `MyISAM' table, but not over all the
     underlying tables in the collection.

   * Because the `MERGE' engine cannot enforce uniqueness over the set
     of underlying tables, *Note `REPLACE': replace. does not work as
     expected. The two key facts are:

        * *Note `REPLACE': replace. can detect unique key violations
          only in the underlying table to which it is going to write
          (which is determined by the `INSERT_METHOD' option). This
          differs from violations in the `MERGE' table itself.

        * If *Note `REPLACE': replace. detects a unique key violation,
          it will change only the corresponding row in the underlying
          table it is writing to; that is, the first or last table, as
          determined by the `INSERT_METHOD' option.

     Similar considerations apply for *Note `INSERT ... ON DUPLICATE
     KEY UPDATE': insert-on-duplicate.

   * You should not use *Note `ANALYZE TABLE': analyze-table, *Note
     `REPAIR TABLE': repair-table, *Note `OPTIMIZE TABLE':
     optimize-table, *Note `ALTER TABLE': alter-table, *Note `DROP
     TABLE': drop-table, *Note `DELETE': delete. without a `WHERE'
     clause, or *Note `TRUNCATE TABLE': truncate-table. on any of the
     tables that are mapped into an open `MERGE' table. If you do so,
     the `MERGE' table may still refer to the original table and yield
     unexpected results. To work around this problem, ensure that no
     `MERGE' tables remain open by issuing a *Note `FLUSH TABLES':
     flush.  statement prior to performing any of the named operations.

     The unexpected results include the possibility that the operation
     on the `MERGE' table will report table corruption. If this occurs
     after one of the named operations on the underlying `MyISAM'
     tables, the corruption message is spurious. To deal with this,
     issue a *Note `FLUSH TABLES': flush.  statement after modifying
     the `MyISAM' tables.

   * *Note `DROP TABLE': drop-table. on a table that is in use by a
     `MERGE' table does not work on Windows because the `MERGE' storage
     engine's table mapping is hidden from the upper layer of MySQL.
     Windows does not permit open files to be deleted, so you first must
     flush all `MERGE' tables (with *Note `FLUSH TABLES': flush.)  or
     drop the `MERGE' table before dropping the table.

   * As of MySQL 5.0.36, the definition of the `MyISAM' tables and the
     `MERGE' table are checked when the tables are accessed (for
     example, as part of a *Note `SELECT': select. or *Note `INSERT':
     insert. statement). The checks ensure that the definitions of the
     tables and the parent `MERGE' table definition match by comparing
     column order, types, sizes and associated indexes. If there is a
     difference between the tables, an error is returned and the
     statement fails. Because these checks take place when the tables
     are opened, any changes to the definition of a single table,
     including column changes, column ordering, and engine alterations
     will cause the statement to fail.

     Prior to MySQL 5.0.36, table checks are applied as follows:

        * When you create or alter `MERGE' table, there is no check to
          ensure that the underlying tables are existing `MyISAM'
          tables and have identical structures. When the `MERGE' table
          is used, MySQL checks that the row length for all mapped
          tables is equal, but this is not foolproof. If you create a
          `MERGE' table from dissimilar `MyISAM' tables, you are very
          likely to run into strange problems.

        * Similarly, if you create a `MERGE' table from non-`MyISAM'
          tables, or if you drop an underlying table or alter it to be a
          non-`MyISAM' table, no error for the `MERGE' table occurs
          until later when you attempt to use it.

        * Because the underlying `MyISAM' tables need not exist when
          the `MERGE' table is created, you can create the tables in
          any order, as long as you do not use the `MERGE' table until
          all of its underlying tables are in place. Also, if you can
          ensure that a `MERGE' table will not be used during a given
          period, you can perform maintenance operations on the
          underlying tables, such as backing up or restoring them,
          altering them, or dropping and recreating them. It is not
          necessary to redefine the `MERGE' table temporarily to
          exclude the underlying tables while you are operating on them.

   * The order of indexes in the `MERGE' table and its underlying
     tables should be the same. If you use *Note `ALTER TABLE':
     alter-table. to add a `UNIQUE' index to a table used in a `MERGE'
     table, and then use *Note `ALTER TABLE': alter-table. to add a
     nonunique index on the `MERGE' table, the index ordering is
     different for the tables if there was already a nonunique index in
     the underlying table. (This happens because *Note `ALTER TABLE':
     alter-table. puts `UNIQUE' indexes before nonunique indexes to
     facilitate rapid detection of duplicate keys.) Consequently,
     queries on tables with such indexes may return unexpected results.

   * If you encounter an error message similar to `ERROR 1017 (HY000):
     Can't find file: 'TBL_NAME.MRG' (errno: 2)', it generally
     indicates that some of the underlying tables do not use the
     `MyISAM' storage engine. Confirm that all of these tables are
     `MyISAM'.

   * The maximum number of rows in a `MERGE' table is 2^32 (~4.295E+09;
     the same as for a `MyISAM' table). It is not possible to merge
     multiple `MyISAM' tables into a single `MERGE' table that would
     have more than this number of rows. However, if you build MySQL
     using the `--with-big-tables' option, then the maximum number of
     rows is increased to 2^64 (1.844E+19); for more information, see
     *Note source-configuration-options::.

     *Note*:

     As of MySQL 5.0.4, all standard binaries are built with this
     option.

   * The `MERGE' storage engine does not support *Note `INSERT
     DELAYED': insert-delayed. statements.

   * Using `MERGE' on underlying `MyISAM' tables that have different row
     formats is possible.

   * In some cases, differing `PACK_KEYS' table option values among the
     `MERGE' and underlying tables cause unexpected results if the
     underlying tables contain `CHAR' or `BINARY' columns. As a
     workaround, use `ALTER TABLE' to ensure that all involved tables
     have the same `PACK_KEYS' value. (Bug #50646)


File: manual.info,  Node: memory-storage-engine,  Next: bdb-storage-engine,  Prev: merge-storage-engine,  Up: storage-engines

14.4 The `MEMORY' (`HEAP') Storage Engine
=========================================

The `MEMORY' storage engine creates tables with contents that are
stored in memory. Formerly, these were known as `HEAP' tables. `MEMORY'
is the preferred term, although `HEAP' remains supported for backward
compatibility.

The `MEMORY' storage engine associates each table with one disk file.
The file name begins with the table name and has an extension of `.frm'
to indicate that it stores the table definition.

To specify that you want to create a `MEMORY' table, indicate that with
an `ENGINE' table option:

     CREATE TABLE t (i INT) ENGINE = MEMORY;

The older term `TYPE' is supported as a synonym for `ENGINE' for
backward compatibility, but `ENGINE' is the preferred term and `TYPE'
is deprecated.

As indicated by the engine name, `MEMORY' tables are stored in memory.
They use hash indexes by default, which makes them very fast, and very
useful for creating temporary tables.  However, when the server shuts
down, all rows stored in `MEMORY' tables are lost. The tables themselves
continue to exist because their definitions are stored in `.frm' files
on disk, but they are empty when the server restarts.

This example shows how you might create, use, and remove a `MEMORY'
table:

     mysql> CREATE TABLE test ENGINE=MEMORY
         ->     SELECT ip,SUM(downloads) AS down
         ->     FROM log_table GROUP BY ip;
     mysql> SELECT COUNT(ip),AVG(down) FROM test;
     mysql> DROP TABLE test;

`MEMORY' tables have the following characteristics:

   * Space for `MEMORY' tables is allocated in small blocks. Tables use
     100% dynamic hashing for inserts. No overflow area or extra key
     space is needed. No extra space is needed for free lists. Deleted
     rows are put in a linked list and are reused when you insert new
     data into the table.  `MEMORY' tables also have none of the
     problems commonly associated with deletes plus inserts in hashed
     tables.

   * `MEMORY' tables can have up to 64 indexes per table, 16 columns
     per index and a maximum key length of 3072 bytes.

   * The `MEMORY' storage engine supports both `HASH' and `BTREE'
     indexes.  You can specify one or the other for a given index by
     adding a `USING' clause as shown here:

          CREATE TABLE lookup
              (id INT, INDEX USING HASH (id))
              ENGINE = MEMORY;
          CREATE TABLE lookup
              (id INT, INDEX USING BTREE (id))
              ENGINE = MEMORY;

     For general characteristics of B-tree and hash indexes, see *Note
     mysql-indexes::.

   * If a `MEMORY' table hash index has a high degree of key
     duplication (many index entries containing the same value),
     updates to the table that affect key values and all deletes are
     significantly slower. The degree of this slowdown is proportional
     to the degree of duplication (or, inversely proportional to the
     index cardinality). You can use a `BTREE' index to avoid this
     problem.

   * `MEMORY' tables can have nonunique keys. (This is an uncommon
     feature for implementations of hash indexes.)

   * Columns that are indexed can contain `NULL' values.

   * `MEMORY' tables use a fixed-length row-storage format.
     Variable-length types such as *Note `VARCHAR': char. are stored
     using a fixed length.

   * `MEMORY' tables cannot contain *Note `BLOB': blob. or *Note
     `TEXT': blob. columns.

   * `MEMORY' includes support for `AUTO_INCREMENT' columns.

   * `MEMORY' supports *Note `INSERT DELAYED': insert-delayed. See
     *Note insert-delayed::.

   * Non-`TEMPORARY' `MEMORY' tables are shared among all clients, just
     like any other non-`TEMPORARY' table.

   * `MEMORY' table contents are stored in memory, which is a property
     that `MEMORY' tables share with internal temporary tables that the
     server creates on the fly while processing queries. However, the
     two types of tables differ in that `MEMORY' tables are not subject
     to storage conversion, whereas internal temporary tables are:

        * `MEMORY' tables are never converted to disk tables. If an
          internal temporary table becomes too large, the server
          automatically converts it to on-disk storage, as described in
          *Note internal-temporary-tables::.

        * The maximum size of `MEMORY' tables is limited by the
          `max_heap_table_size' system variable, which has a default
          value of 16MB. To have larger (or smaller) `MEMORY' tables,
          you must change the value of this variable. The value in
          effect for *Note `CREATE TABLE': create-table. is the value
          used for the life of the table. (If you use *Note `ALTER
          TABLE': alter-table. or *Note `TRUNCATE TABLE':
          truncate-table, the value in effect at that time becomes the
          new maximum size for the table. A server restart also sets
          the maximum size of existing `MEMORY' tables to the global
          `max_heap_table_size' value.)  You can set the size for
          individual tables as described later in this section.

   * The server needs sufficient memory to maintain all `MEMORY' tables
     that are in use at the same time.

   * Memory is not reclaimed if you delete individual rows from a
     `MEMORY' table. Memory is reclaimed only when the entire table is
     deleted. Memory that was previously used for rows that have been
     deleted will be re-used for new rows only within the same table.
     To free up the memory used by rows that have been deleted, use
     `ALTER TABLE ENGINE=MEMORY' to force a table rebuild.

     To free all the memory used by a `MEMORY' table when you no longer
     require its contents, you should execute *Note `DELETE': delete. or
     *Note `TRUNCATE TABLE': truncate-table. to remove all rows, or
     remove the table altogether using *Note `DROP TABLE': drop-table.

   * If you want to populate a `MEMORY' table when the MySQL server
     starts, you can use the `--init-file' option. For example, you can
     put statements such as *Note `INSERT INTO ... SELECT':
     insert-select. or *Note `LOAD DATA INFILE': load-data. into this
     file to load the table from a persistent data source. See *Note
     server-options::, and *Note load-data::.

   * A server's `MEMORY' tables become empty when it is shut down and
     restarted. However, if the server is a replication master, its
     slave are not aware that these tables have become empty, so they
     returns out-of-date content if you select data from these tables.
     To handle this, when a `MEMORY' table is used on a master for the
     first time since it was started, a *Note `DELETE': delete.
     statement is written to the master's binary log automatically,
     thus synchronizing the slave to the master again. Note that even
     with this strategy, the slave still has outdated data in the table
     during the interval between the master's restart and its first use
     of the table. However, if you use the `--init-file' option to
     populate the `MEMORY' table on the master at startup, it ensures
     that this time interval is zero.

   * The memory needed for one row in a `MEMORY' table is calculated
     using the following expression:

          SUM_OVER_ALL_BTREE_KEYS(MAX_LENGTH_OF_KEY + sizeof(char*) x 4)
          + SUM_OVER_ALL_HASH_KEYS(sizeof(char*) x 2)
          + ALIGN(LENGTH_OF_ROW+1, sizeof(char*))

     `ALIGN()' represents a round-up factor to cause the row length to
     be an exact multiple of the `char' pointer size.  `sizeof(char*)'
     is 4 on 32-bit machines and 8 on 64-bit machines.

As mentioned earlier, the `max_heap_table_size' system variable sets
the limit on the maximum size of `MEMORY' tables. To control the
maximum size for individual tables, set the session value of this
variable before creating each table. (Do not change the global
`max_heap_table_size' value unless you intend the value to be used for
`MEMORY' tables created by all clients.) The following example creates
two `MEMORY' tables, with a maximum size of 1MB and 2MB, respectively:

     mysql> SET max_heap_table_size = 1024*1024;
     Query OK, 0 rows affected (0.00 sec)

     mysql> CREATE TABLE t1 (id INT, UNIQUE(id)) ENGINE = MEMORY;
     Query OK, 0 rows affected (0.01 sec)

     mysql> SET max_heap_table_size = 1024*1024*2;
     Query OK, 0 rows affected (0.00 sec)

     mysql> CREATE TABLE t2 (id INT, UNIQUE(id)) ENGINE = MEMORY;
     Query OK, 0 rows affected (0.00 sec)

Both tables will revert to the server's global `max_heap_table_size'
value if the server restarts.

You can also specify a `MAX_ROWS' table option in *Note `CREATE TABLE':
create-table. statements for `MEMORY' tables to provide a hint about
the number of rows you plan to store in them. This does not enable the
table to grow beyond the `max_heap_table_size' value, which still acts
as a constraint on maximum table size. For maximum flexibility in being
able to use `MAX_ROWS', set `max_heap_table_size' at least as high as
the value to which you want each `MEMORY' table to be able to grow.

* Additional Resources *

   * A forum dedicated to the `MEMORY' storage engine is available at
     `http://forums.mysql.com/list.php?92'.


File: manual.info,  Node: bdb-storage-engine,  Next: example-storage-engine,  Prev: memory-storage-engine,  Up: storage-engines

14.5 The `BDB' (`BerkeleyDB') Storage Engine
============================================

* Menu:

* bdb-portability::              Operating Systems Supported by `BDB'
* bdb-install::                  Installing `BDB'
* bdb-start::                    `BDB' Startup Options
* bdb-characteristics::          Characteristics of `BDB' Tables
* bdb-restrictions::             Restrictions on `BDB' Tables
* bdb-errors::                   Errors That May Occur When Using `BDB' Tables

Sleepycat Software has provided MySQL with the Berkeley DB
transactional storage engine. This storage engine typically is called
`BDB' for short. `BDB' tables may have a greater chance of surviving
crashes and are also capable of *Note `COMMIT': commit. and *Note
`ROLLBACK': commit.  operations on transactions.

Support for the `BDB' storage engine is included in MySQL source
distributions, which come with a `BDB' distribution that is patched to
make it work with MySQL. You cannot use an unpatched version of `BDB'
with MySQL.

BDB support will be removed

Note that, as of MySQL 5.1, `BDB' isn't supported any longer.

For general information about Berkeley DB, please visit the Sleepycat
Web site, `http://www.sleepycat.com/'.


File: manual.info,  Node: bdb-portability,  Next: bdb-install,  Prev: bdb-storage-engine,  Up: bdb-storage-engine

14.5.1 Operating Systems Supported by `BDB'
-------------------------------------------

Currently, we know that the `BDB' storage engine works with the
following operating systems:

   * Linux 2.x Intel

   * Sun Solaris (SPARC and x86)

   * FreeBSD 4.x/5.x (x86, sparc64)

   * IBM AIX 4.3.x

   * SCO OpenServer

   * SCO UnixWare 7.1.x

   * Windows

The `BDB' storage engine does _not_ work with the following operating
systems:

   * Linux 2.x Alpha

   * Linux 2.x AMD64

   * Linux 2.x IA-64

   * Linux 2.x s390

   * Mac OS X

*Note*:

The preceding lists are not complete. We update them as we receive more
information.

If you build MySQL from source with support for `BDB' tables, but the
following error occurs when you start *Note `mysqld': mysqld, it means
that the `BDB' storage engine is not supported for your architecture:

     bdb: architecture lacks fast mutexes: applications cannot be threaded
     Can't init databases

In this case, you must rebuild MySQL without `BDB' support or start the
server with the `--skip-bdb' option.


File: manual.info,  Node: bdb-install,  Next: bdb-start,  Prev: bdb-portability,  Up: bdb-storage-engine

14.5.2 Installing `BDB'
-----------------------

If you have downloaded a binary version of MySQL that includes support
for Berkeley DB, simply follow the usual binary distribution
installation instructions.

If you build MySQL from source, you can enable `BDB' support by invoking
`configure' with the `--with-berkeley-db' option in addition to any
other options that you normally use. Download a MySQL 5.0 distribution,
change location into its top-level directory, and run this command:

     shell> ./configure --with-berkeley-db [OTHER-OPTIONS]

For more information, *Note binary-installation::, and *Note
source-installation::.


File: manual.info,  Node: bdb-start,  Next: bdb-characteristics,  Prev: bdb-install,  Up: bdb-storage-engine

14.5.3 `BDB' Startup Options
----------------------------

The following options to *Note `mysqld': mysqld. can be used to change
the behavior of the `BDB' storage engine.  For more information, see
*Note server-options::.

*BDB Option/Variable Reference*

Name           Cmd-Line    Option file System Var  Status Var  Var Scope   Dynamic
bdb_cache_size Yes         Yes         Yes                     Global      No
bdb-home       Yes         Yes                                 Global      No
- _Variable_:                          Yes                     Global      No
bdb_home                                                                   
bdb-lock-detectYes         Yes                                 Global      No
- _Variable_:                          Yes                     Global      No
bdb_lock_detect                                                            
bdb_log_buffer_sizeYes         Yes         Yes                     Global      No
bdb-logdir     Yes         Yes                                 Global      No
- _Variable_:                          Yes                     Global      No
bdb_logdir                                                                 
bdb_max_lock   Yes         Yes         Yes                     Global      No
bdb-no-recover Yes         Yes                                             
bdb-shared-dataYes         Yes                                 Global      No
- _Variable_:                          Yes                     Global      No
bdb_shared_data                                                            
bdb-tmpdir     Yes         Yes                                 Global      No
- _Variable_:                          Yes                     Global      No
bdb_tmpdir                                                                 
have_bdb                               Yes                     Global      No
skip-bdb       Yes         Yes                                             
skip-sync-bdb-logsYes         Yes         Yes                     Global      No
sync-bdb-logs  Yes         Yes                                 Global      No
- _Variable_:                          Yes                     Global      No
sync_bdb_logs                                                              

   *  `--bdb-home=PATH'

     The base directory for `BDB' tables. This should be the same
     directory that you use for `--datadir'.

   *  `--bdb-lock-detect=METHOD'

     The `BDB' lock detection method. The option value should be
     `DEFAULT', `OLDEST', `RANDOM', or `YOUNGEST'.

   *  `--bdb-logdir=FILE_NAME'

     The `BDB' log file directory.

   *  `--bdb-no-recover'

     Do not start Berkeley DB in recover mode.

   *  `--bdb-no-sync'

     Don't synchronously flush the `BDB' logs.  This option is
     deprecated; use `--skip-sync-bdb-logs' instead (see the
     description for `--sync-bdb-logs').

   *  `--bdb-shared-data'

     Start Berkeley DB in multi-process mode. (Do not use `DB_PRIVATE'
     when initializing Berkeley DB.)

   *  `--bdb-tmpdir=PATH'

     The `BDB' temporary file directory.

   * `--skip-bdb'

     Disable the `BDB' storage engine.

   *  `--sync-bdb-logs'

     Synchronously flush the `BDB' logs. This option is enabled by
     default. Use `--skip-sync-bdb-logs' to disable it.

If you use the `--skip-bdb' option, MySQL does not initialize the
Berkeley DB library and this saves a lot of memory. However, if you use
this option, you cannot use `BDB' tables. If you try to create a `BDB'
table, MySQL uses the default storage engine instead.

Normally, you should start *Note `mysqld': mysqld. without the
`--bdb-no-recover' option if you intend to use `BDB' tables. However,
this may cause problems when you try to start *Note `mysqld': mysqld. if
the `BDB' log files are corrupted. See *Note starting-server::.

With the `bdb_max_lock' variable, you can specify the maximum number of
locks that can be active on a `BDB' table. The default is 10,000. You
should increase this if errors such as the following occur when you
perform long transactions or when *Note `mysqld': mysqld. has to
examine many rows to execute a query:

     bdb: Lock table is out of available locks
     Got error 12 from ...

You may also want to change the `binlog_cache_size' and
`max_binlog_cache_size' variables if you are using large
multiple-statement transactions. See *Note binary-log::.

See also *Note server-system-variables::.


File: manual.info,  Node: bdb-characteristics,  Next: bdb-restrictions,  Prev: bdb-start,  Up: bdb-storage-engine

14.5.4 Characteristics of `BDB' Tables
--------------------------------------

Each `BDB' table is stored on disk in two files.  The files have names
that begin with the table name and have an extension to indicate the
file type. An `.frm' file stores the table format, and a `.db' file
contains the table data and indexes.

To specify explicitly that you want a `BDB' table, indicate that with
an `ENGINE' table option:

     CREATE TABLE t (i INT) ENGINE = BDB;

The older term `TYPE' is supported as a synonym for `ENGINE' for
backward compatibility, but `ENGINE' is the preferred term and `TYPE'
is deprecated.

`BerkeleyDB' is a synonym for `BDB' in the `ENGINE' table option.

The `BDB' storage engine provides transactional tables. The way you use
these tables depends on the autocommit mode:

   * If you are running with autocommit enabled (which is the default),
     changes to `BDB' tables are committed immediately and cannot be
     rolled back.

   * If you are running with autocommit disabled, changes do not become
     permanent until you execute a *Note `COMMIT': commit. statement.
     Instead of committing, you can execute *Note `ROLLBACK': commit. to
     forget the changes.

     You can start a transaction with the *Note `START TRANSACTION':
     commit. or *Note `BEGIN': commit.  statement to suspend
     autocommit, or with `SET autocommit = 0' to disable autocommit
     explicitly.

For more information about transactions, see *Note commit::.

The `BDB' storage engine has the following characteristics:

   * `BDB' tables can have up to 31 indexes per table, 16 columns per
     index, and a maximum key size of 1024 bytes.

   * MySQL requires a primary key in each `BDB' table so that each row
     can be uniquely identified. If you don't create one explicitly by
     declaring a `PRIMARY KEY', MySQL creates and maintains a hidden
     primary key for you. The hidden key has a length of five bytes and
     is incremented for each insert attempt. This key does not appear
     in the output of *Note `SHOW CREATE TABLE': show-create-table. or
     *Note `DESCRIBE': describe.

   * The primary key is faster than any other index, because it is
     stored together with the row data. The other indexes are stored as
     the key data plus the primary key, so it is important to keep the
     primary key as short as possible to save disk space and get better
     speed.

     This behavior is similar to that of `InnoDB', where shorter
     primary keys save space not only in the primary index but in
     secondary indexes as well.

   * If all columns that you access in a `BDB' table are part of the
     same index or part of the primary key, MySQL can execute the query
     without having to access the actual row. In a `MyISAM' table, this
     can be done only if the columns are part of the same index.

   * Sequential scanning is slower for `BDB' tables than for `MyISAM'
     tables because the data in `BDB' tables is stored in B-trees and
     not in a separate data file.

   * Key values are not prefix- or suffix-compressed like key values in
     `MyISAM' tables. In other words, key information takes a little
     more space in `BDB' tables compared to `MyISAM' tables.

   * There are often holes in the `BDB' table to permit you to insert
     new rows in the middle of the index tree.  This makes `BDB' tables
     somewhat larger than `MyISAM' tables.

   * `SELECT COUNT(*) FROM TBL_NAME' is slow for `BDB' tables, because
     no row count is maintained in the table.

   * The optimizer needs to know the approximate number of rows in the
     table. MySQL solves this by counting inserts and maintaining this
     in a separate segment in each `BDB' table. If you don't issue a
     lot of *Note `DELETE': delete. or *Note `ROLLBACK': commit.
     statements, this number should be accurate enough for the MySQL
     optimizer. However, MySQL stores the number only on close, so it
     may be incorrect if the server terminates unexpectedly. It should
     not be fatal even if this number is not 100% correct. You can
     update the row count by using *Note `ANALYZE TABLE':
     analyze-table. or *Note `OPTIMIZE TABLE': optimize-table. See
     *Note analyze-table::, and *Note optimize-table::.

   * Internal locking in `BDB' tables is done at the page level.

   * *Note `LOCK TABLES': lock-tables. works on `BDB' tables as with
     other tables. If you do not use *Note `LOCK TABLES': lock-tables,
     MySQL issues an internal multiple-write lock on the table (a lock
     that does not block other writers) to ensure that the table is
     properly locked if another thread issues a table lock.

   * To support transaction rollback, the `BDB' storage engine
     maintains log files. For maximum performance, you can use the
     `--bdb-logdir' option to place the `BDB' logs on a different disk
     than the one where your databases are located.

   * MySQL performs a checkpoint each time a new `BDB' log file is
     started, and removes any `BDB' log files that are not needed for
     current transactions. You can also use *Note `FLUSH LOGS': flush.
     at any time to checkpoint the Berkeley DB tables.

     For disaster recovery, you should use table backups plus MySQL's
     binary log. See *Note backup-methods::.

     *Warning*:

     If you delete old log files that are still in use, `BDB' is not
     able to do recovery at all and you may lose data if something goes
     wrong.

   * Applications must always be prepared to handle cases where any
     change of a `BDB' table may cause an automatic rollback and any
     read may fail with a deadlock error.

   * If you get a full disk with a `BDB' table, you get an error
     (probably error 28) and the transaction should roll back. This
     contrasts with `MyISAM' tables, for which *Note `mysqld': mysqld.
     waits for sufficient free disk space before continuing.


File: manual.info,  Node: bdb-restrictions,  Next: bdb-errors,  Prev: bdb-characteristics,  Up: bdb-storage-engine

14.5.5 Restrictions on `BDB' Tables
-----------------------------------

The following list indicates restrictions that you must observe when
using `BDB' tables:

   * Each `BDB' table stores in its `.db' file the path to the file as
     it was created. This is done to enable detection of locks in a
     multi-user environment that supports symlinks. As a consequence of
     this, it is not possible to move `BDB' table files from one
     database directory to another.

   * When making backups of `BDB' tables, you must either use *Note
     `mysqldump': mysqldump. or else make a backup that includes the
     files for each `BDB' table (the `.frm' and `.db' files) as well as
     the `BDB' log files. The `BDB' storage engine stores unfinished
     transactions in its log files and requires them to be present when
     *Note `mysqld': mysqld. starts. The `BDB' logs are the files in
     the data directory with names of the form `log.NNNNNNNNNN' (ten
     digits).

   * If a column that permits `NULL' values has a unique index, only a
     single `NULL' value is permitted. This differs from other storage
     engines, which permit multiple `NULL' values in unique indexes.


File: manual.info,  Node: bdb-errors,  Prev: bdb-restrictions,  Up: bdb-storage-engine

14.5.6 Errors That May Occur When Using `BDB' Tables
----------------------------------------------------

   * If the following error occurs when you start *Note `mysqld':
     mysqld. after upgrading, it means that the current version of
     `BDB' doesn't support the old log file format:

          bdb:  Ignoring log file: .../log.NNNNNNNNNN:
          unsupported log version #

     In this case, you must delete all `BDB' logs from your data
     directory (the files that have names of the form `log.NNNNNNNNNN')
     and restart *Note `mysqld': mysqld. We also recommend that you
     then use *Note `mysqldump --opt': mysqldump. to dump your `BDB'
     tables, drop the tables, and restore them from the dump file.

   * If autocommit mode is disabled and you drop a `BDB' table that is
     referenced in another transaction, you may get error messages of
     the following form in your MySQL error log:

          001119 23:43:56  bdb:  Missing log fileid entry
          001119 23:43:56  bdb:  txn_abort: Log undo failed for LSN:
                                 1 3644744: Invalid

     This is not fatal, but the fix is not trivial. Avoid dropping
     `BDB' tables except while autocommit mode is enabled.


File: manual.info,  Node: example-storage-engine,  Next: federated-storage-engine,  Prev: bdb-storage-engine,  Up: storage-engines

14.6 The `EXAMPLE' Storage Engine
=================================

The `EXAMPLE' storage engine is a stub engine that does nothing. Its
purpose is to serve as an example in the MySQL source code that
illustrates how to begin writing new storage engines. As such, it is
primarily of interest to developers.

The `EXAMPLE' storage engine is included in MySQL binary distributions.
To enable this storage engine if you build MySQL from source, invoke
`configure' with the `--with-example-storage-engine' option.

To examine the source for the `EXAMPLE' engine, look in the
`sql/examples' directory of a MySQL source distribution.

When you create an `EXAMPLE' table, the server creates a table format
file in the database directory. The file begins with the table name and
has an `.frm' extension. No other files are created. No data can be
stored into the table. Retrievals return an empty result.

     mysql> CREATE TABLE test (i INT) ENGINE = EXAMPLE;
     Query OK, 0 rows affected (0.78 sec)

     mysql> INSERT INTO test VALUES(1),(2),(3);
     ERROR 1031 (HY000): Table storage engine for 'test' doesn't have this option

     mysql> SELECT * FROM test;
     Empty set (0.31 sec)

The `EXAMPLE' storage engine does not support indexing.


File: manual.info,  Node: federated-storage-engine,  Next: archive-storage-engine,  Prev: example-storage-engine,  Up: storage-engines

14.7 The `FEDERATED' Storage Engine
===================================

* Menu:

* federated-description::        Description of the `FEDERATED' Storage Engine
* federated-use::                How to Use `FEDERATED' Tables
* federated-limitations::        Limitations of the `FEDERATED' Storage Engine

The `FEDERATED' storage engine is available beginning with MySQL 5.0.3.
It is a storage engine that accesses data in tables of remote databases
rather than in local tables.

The `FEDERATED' storage engine is available beginning with MySQL 5.0.3.
This storage engine enables data to be accessed from a remote MySQL
database on a local server without using replication or cluster
technology. When using a `FEDERATED' table, queries on the local server
are automatically executed on the remote (federated) tables. No data is
stored on the local tables.

To include the `FEDERATED' storage engine if you build MySQL from
source, invoke `configure' with the `--with-federated-storage-engine'
option.

Beginning with MySQL 5.0.64, the `FEDERATED' storage engine is not
enabled by default in the running server; to enable `FEDERATED', you
must start the MySQL server binary using the `--federated' option.

To examine the source for the `FEDERATED' engine, look in the `sql'
directory of a source distribution for MySQL 5.0.3 or newer.

* Additional Resources *

   * A forum dedicated to the `FEDERATED' storage engine is available
     at `http://forums.mysql.com/list.php?105'.


File: manual.info,  Node: federated-description,  Next: federated-use,  Prev: federated-storage-engine,  Up: federated-storage-engine

14.7.1 Description of the `FEDERATED' Storage Engine
----------------------------------------------------

When you create a `FEDERATED' table, the server creates a table format
file in the database directory. The file begins with the table name and
has an `.frm' extension. No other files are created, because the actual
data is in a remote table. This differs from the way that storage
engines for local tables work.

For local database tables, data files are local. For example, if you
create a `MyISAM' table named `users', the `MyISAM' handler creates a
data file named `users.MYD'. A handler for local tables reads, inserts,
deletes, and updates data in local data files, and rows are stored in a
format particular to the handler. To read rows, the handler must parse
data into columns. To write rows, column values must be converted to
the row format used by the handler and written to the local data file.

With the MySQL `FEDERATED' storage engine, there are no local data
files for a table (for example, there is no `.MYD' file). Instead, a
remote database stores the data that normally would be in the table.
The local server connects to a remote server, and uses the MySQL client
API to read, delete, update, and insert data in the remote table. For
example, data retrieval is initiated using a `SELECT * FROM TBL_NAME'
SQL statement.

When a client issues an SQL statement that refers to a `FEDERATED'
table, the flow of information between the local server (where the SQL
statement is executed) and the remote server (where the data is
physically stored) is as follows:

  1. The storage engine looks through each column that the `FEDERATED'
     table has and constructs an appropriate SQL statement that refers
     to the remote table.

  2. The statement is sent to the remote server using the MySQL client
     API.

  3. The remote server processes the statement and the local server
     retrieves any result that the statement produces (an affected-rows
     count or a result set).

  4. If the statement produces a result set, each column is converted
     to internal storage engine format that the `FEDERATED' engine
     expects and can use to display the result to the client that
     issued the original statement.

The local server communicates with the remote server using MySQL client
C API functions. It invokes *Note `mysql_real_query()':
mysql-real-query. to send the statement. To read a result set, it uses
*Note `mysql_store_result()': mysql-store-result. and fetches rows one
at a time using *Note `mysql_fetch_row()': mysql-fetch-row.


File: manual.info,  Node: federated-use,  Next: federated-limitations,  Prev: federated-description,  Up: federated-storage-engine

14.7.2 How to Use `FEDERATED' Tables
------------------------------------

The procedure for using `FEDERATED' tables is very simple. Normally,
you have two servers running, either both on the same host or on
different hosts. (It is possible for a `FEDERATED' table to use another
table that is managed by the same server, although there is little
point in doing so.)

First, you must have a table on the remote server that you want to
access by using a `FEDERATED' table. Suppose that the remote table is
in the `federated' database and is defined like this:

     CREATE TABLE test_table (
         id     INT(20) NOT NULL AUTO_INCREMENT,
         name   VARCHAR(32) NOT NULL DEFAULT '',
         other  INT(20) NOT NULL DEFAULT '0',
         PRIMARY KEY  (id),
         INDEX name (name),
         INDEX other_key (other)
     )
     ENGINE=MyISAM
     DEFAULT CHARSET=latin1;

The example uses a `MyISAM' table, but the table could use any storage
engine.

Next, create a `FEDERATED' table on the local server for accessing the
remote table:

     CREATE TABLE federated_table (
         id     INT(20) NOT NULL AUTO_INCREMENT,
         name   VARCHAR(32) NOT NULL DEFAULT '',
         other  INT(20) NOT NULL DEFAULT '0',
         PRIMARY KEY  (id),
         INDEX name (name),
         INDEX other_key (other)
     )
     ENGINE=FEDERATED
     DEFAULT CHARSET=latin1
     CONNECTION='mysql://fed_user@remote_host:9306/federated/test_table';

(Before MySQL 5.0.13, use `COMMENT' rather than `CONNECTION'.)

The basic structure of this table should match that of the remote
table, except that the `ENGINE' table option should be `FEDERATED' and
the `CONNECTION' table option is a connection string that indicates to
the `FEDERATED' engine how to connect to the remote server.

*Note*:

You can improve the performance of a `FEDERATED' table by adding
indexes to the table on the host. The optimization will occur because
the query sent to the remote server will include the contents of the
`WHERE' clause and will be sent to the remote server and subsequently
executed locally. This reduces the network traffic that would otherwise
request the entire table from the server for local processing.

The `FEDERATED' engine creates only the `test_table.frm' file in the
`federated' database.

The remote host information indicates the remote server to which your
local server connects, and the database and table information indicates
which remote table to use as the data source. In this example, the
remote server is indicated to be running as `remote_host' on port 9306,
so there must be a MySQL server running on the remote host and
listening to port 9306.

The general format of the connection string in the `CONNECTION' option
is as follows:

     SCHEME://USER_NAME[:PASSWORD]@HOST_NAME[:PORT_NUM]/DB_NAME/TBL_NAME

Only `mysql' is supported as the SCHEME value at this point; the
password and port number are optional.

Sample connection strings:

     CONNECTION='mysql://username:password@hostname:port/database/tablename'
     CONNECTION='mysql://username@hostname/database/tablename'
     CONNECTION='mysql://username:password@hostname/database/tablename'

The use of `CONNECTION' for specifying the connection string is
nonoptimal and is likely to change in future.  Keep this in mind for
applications that use `FEDERATED' tables. Such applications are likely
to need modification if the format for specifying connection
information changes.

Because any password given in the connection string is stored as plain
text, it can be seen by any user who can use *Note `SHOW CREATE TABLE':
show-create-table. or *Note `SHOW TABLE STATUS': show-table-status. for
the `FEDERATED' table, or query the *Note `TABLES': tables-table. table
in the `INFORMATION_SCHEMA' database.


File: manual.info,  Node: federated-limitations,  Prev: federated-use,  Up: federated-storage-engine

14.7.3 Limitations of the `FEDERATED' Storage Engine
----------------------------------------------------

The following items indicate features that the `FEDERATED' storage
engine does and does not support:

   * The remote server must be a MySQL server.

   * The remote table that a `FEDERATED' table points to _must_ exist
     before you try to access the table through the `FEDERATED' table.

   * It is possible for one `FEDERATED' table to point to another, but
     you must be careful not to create a loop.

   * There is no support for transactions.

   * A `FEDERATED' table does not support indexes per se. Because
     access to the table is handled remotely, it is the remote table
     that supports the indexes. Care should be taken when creating a
     `FEDERATED' table since the index definition from an equivalent
     `MyISAM' or other table may not be supported.  For example,
     creating a `FEDERATED' table with an index prefix on *Note
     `VARCHAR': char, *Note `TEXT': blob. or *Note `BLOB': blob.
     columns will fail. The following definition in `MyISAM' is valid:

          CREATE TABLE `T1`(`A` VARCHAR(100),UNIQUE KEY(`A`(30))) ENGINE=MYISAM;

     The key prefix in this example is incompatible with the
     `FEDERATED' engine, and the equivalent statement will fail:

          CREATE TABLE `T1`(`A` VARCHAR(100),UNIQUE KEY(`A`(30))) ENGINE=FEDERATED
            CONNECTION='MYSQL://127.0.0.1:3306/TEST/T1';

     If possible, you should try to separate the column and index
     definition when creating tables on both the remote server and the
     local server to avoid these index issues.

   * Internally, the implementation uses *Note `SELECT': select, *Note
     `INSERT': insert, *Note `UPDATE': update, and *Note `DELETE':
     delete, but not *Note `HANDLER': handler.

   * The `FEDERATED' storage engine supports *Note `SELECT': select,
     *Note `INSERT': insert, *Note `UPDATE': update, *Note `DELETE':
     delete, and indexes. It does not support *Note `ALTER TABLE':
     alter-table, or any Data Definition Language statements that
     directly affect the structure of the table, other than *Note `DROP
     TABLE': drop-table. The current implementation does not use
     prepared statements.

   * `FEDERATED' accepts *Note `INSERT ... ON DUPLICATE KEY UPDATE':
     insert-on-duplicate. statements, but if a duplicate-key violation
     occurs, the statement fails with an error.

   * Performance on a `FEDERATED' table when performing bulk inserts
     (for example, on a *Note `INSERT INTO ... SELECT ...':
     insert-select. statement) is slower than with other table types
     because each selected row is treated as an individual *Note
     `INSERT': insert. statement on the federated table.

   * Before MySQL 5.0.46, for a multiple-row insert into a `FEDERATED'
     table that refers to a remote transactional table, if the insert
     failed for a row due to constraint failure, the remote table would
     contain a partial commit (the rows preceding the failed one)
     instead of rolling back the statement completely. This occurred
     because the rows were treated as individual inserts.

     As of MySQL 5.0.46, `FEDERATED' performs bulk-insert handling such
     that multiple rows are sent to the remote table in a batch. This
     provides a performance improvement. Also, if the remote table is
     transactional, it enables the remote storage engine to perform
     statement rollback properly should an error occur. This capability
     has the following limitations:

        * The size of the insert cannot exceed the maximum packet size
          between servers. If the insert exceeds this size, it is
          broken into multiple packets and the rollback problem can
          occur.

        * Bulk-insert handling does not occur for *Note `INSERT ... ON
          DUPLICATE KEY UPDATE': insert-on-duplicate.

   * There is no way for the `FEDERATED' engine to know if the remote
     table has changed. The reason for this is that this table must
     work like a data file that would never be written to by anything
     other than the database system. The integrity of the data in the
     local table could be breached if there was any change to the
     remote database.

   * Any *Note `DROP TABLE': drop-table. statement issued against a
     `FEDERATED' table drops only the local table, not the remote table.

   * `FEDERATED' tables do not work with the query cache.


File: manual.info,  Node: archive-storage-engine,  Next: csv-storage-engine,  Prev: federated-storage-engine,  Up: storage-engines

14.8 The `ARCHIVE' Storage Engine
=================================

The `ARCHIVE' storage engine is used for storing large amounts of data
without indexes in a very small footprint.

The `ARCHIVE' storage engine is included in MySQL binary distributions.
To enable this storage engine if you build MySQL from source, invoke
`configure' with the `--with-archive-storage-engine' option.

To examine the source for the `ARCHIVE' engine, look in the `sql'
directory of a MySQL source distribution.

You can check whether the `ARCHIVE' storage engine is available with
this statement:

     mysql> SHOW VARIABLES LIKE 'have_archive';

When you create an `ARCHIVE' table, the server creates a table format
file in the database directory. The file begins with the table name and
has an `.frm' extension. The storage engine creates other files, all
having names beginning with the table name. The data and metadata files
have extensions of `.ARZ' and `.ARM', respectively. An `.ARN' file may
appear during optimization operations.

The `ARCHIVE' engine supports *Note `INSERT': insert. and *Note
`SELECT': select, but not *Note `DELETE': delete, *Note `REPLACE':
replace, or *Note `UPDATE': update. It does support `ORDER BY'
operations, *Note `BLOB': blob. columns, and basically all but spatial
data types (see *Note mysql-spatial-datatypes::).  The `ARCHIVE' engine
uses row-level locking.

*Storage:* Rows are compressed as they are inserted. The `ARCHIVE'
engine uses `zlib' lossless data compression (see
`http://www.zlib.net/'). You can use *Note `OPTIMIZE TABLE':
optimize-table. to analyze the table and pack it into a smaller format
(for a reason to use *Note `OPTIMIZE TABLE': optimize-table, see later
in this section). Beginning with MySQL 5.0.15, the engine also supports
*Note `CHECK TABLE': check-table. There are several types of insertions
that are used:

   * An *Note `INSERT': insert. statement just pushes rows into a
     compression buffer, and that buffer flushes as necessary. The
     insertion into the buffer is protected by a lock.  A *Note
     `SELECT': select. forces a flush to occur, unless the only
     insertions that have come in were *Note `INSERT DELAYED':
     insert-delayed. (those flush as necessary). See *Note
     insert-delayed::.

   * A bulk insert is visible only after it completes, unless other
     inserts occur at the same time, in which case it can be seen
     partially. A *Note `SELECT': select. never causes a flush of a
     bulk insert unless a normal insert occurs while it is loading.

*Retrieval*: On retrieval, rows are uncompressed on demand; there is no
row cache. A *Note `SELECT': select. operation performs a complete
table scan: When a *Note `SELECT': select. occurs, it finds out how
many rows are currently available and reads that number of rows. *Note
`SELECT': select. is performed as a consistent read. Note that lots of
*Note `SELECT': select. statements during insertion can deteriorate the
compression, unless only bulk or delayed inserts are used. To achieve
better compression, you can use *Note `OPTIMIZE TABLE': optimize-table.
or *Note `REPAIR TABLE': repair-table. The number of rows in `ARCHIVE'
tables reported by *Note `SHOW TABLE STATUS': show-table-status. is
always accurate.  See *Note optimize-table::, *Note repair-table::, and
*Note show-table-status::.

* Additional Resources *

   * A forum dedicated to the `ARCHIVE' storage engine is available at
     `http://forums.mysql.com/list.php?112'.


File: manual.info,  Node: csv-storage-engine,  Next: blackhole-storage-engine,  Prev: archive-storage-engine,  Up: storage-engines

14.9 The `CSV' Storage Engine
=============================

The `CSV' storage engine stores data in text files using
comma-separated values format. It is unavailable on Windows until MySQL
5.1.

The `CSV' storage engine is included in MySQL binary distributions
(except on Windows). To enable this storage engine if you build MySQL
from source, invoke `configure' with the `--with-csv-storage-engine'
option.

To examine the source for the `CSV' engine, look in the `sql/examples'
directory of a MySQL source distribution.

When you create a `CSV' table, the server creates a table format file
in the database directory. The file begins with the table name and has
an `.frm' extension. The storage engine also creates a data file. Its
name begins with the table name and has a `.CSV' extension. The data
file is a plain text file. When you store data into the table, the
storage engine saves it into the data file in comma-separated values
format.

     mysql> CREATE TABLE test (i INT NOT NULL, c CHAR(10) NOT NULL)
         -> ENGINE = CSV;
     Query OK, 0 rows affected (0.12 sec)

     mysql> INSERT INTO test VALUES(1,'record one'),(2,'record two');
     Query OK, 2 rows affected (0.00 sec)
     Records: 2  Duplicates: 0  Warnings: 0

     mysql> SELECT * FROM test;
     +------+------------+
     | i    | c          |
     +------+------------+
     |    1 | record one |
     |    2 | record two |
     +------+------------+
     2 rows in set (0.00 sec)

If you examine the `test.CSV' file in the database directory created by
executing the preceding statements, its contents should look like this:

     "1","record one"
     "2","record two"

This format can be read, and even written, by spreadsheet applications
such as Microsoft Excel or StarOffice Calc.

The `CSV' storage engine does not support indexing.


File: manual.info,  Node: blackhole-storage-engine,  Prev: csv-storage-engine,  Up: storage-engines

14.10 The `BLACKHOLE' Storage Engine
====================================

The `BLACKHOLE' storage engine acts as a `black hole' that accepts data
but throws it away and does not store it. Retrievals always return an
empty result:

     mysql> CREATE TABLE test(i INT, c CHAR(10)) ENGINE = BLACKHOLE;
     Query OK, 0 rows affected (0.03 sec)

     mysql> INSERT INTO test VALUES(1,'record one'),(2,'record two');
     Query OK, 2 rows affected (0.00 sec)
     Records: 2  Duplicates: 0  Warnings: 0

     mysql> SELECT * FROM test;
     Empty set (0.00 sec)

The `BLACKHOLE' storage engine is included in MySQL binary
distributions. To enable this storage engine if you build MySQL from
source, invoke `configure' with the `--with-blackhole-storage-engine'
option.

To examine the source for the `BLACKHOLE' engine, look in the `sql'
directory of a MySQL source distribution.

When you create a `BLACKHOLE' table, the server creates a table format
file in the database directory. The file begins with the table name and
has an `.frm' extension. There are no other files associated with the
table.

The `BLACKHOLE' storage engine supports all kinds of indexes. That is,
you can include index declarations in the table definition.

You can check whether the `BLACKHOLE' storage engine is available with
this statement:

     mysql> SHOW VARIABLES LIKE 'have_blackhole_engine';

Inserts into a `BLACKHOLE' table do not store any data, but if the
binary log is enabled, the SQL statements are logged (and replicated to
slave servers). This can be useful as a repeater or filter mechanism.
Suppose that your application requires slave-side filtering rules, but
transferring all binary log data to the slave first results in too much
traffic. In such a case, it is possible to set up on the master host a
`dummy' slave process whose default storage engine is `BLACKHOLE',
depicted as follows:

Replication using `BLACKHOLE' for filtering

The master writes to its binary log. The `dummy' *Note `mysqld':
mysqld. process acts as a slave, applying the desired combination of
`replicate-do-*' and `replicate-ignore-*' rules, and writes a new,
filtered binary log of its own. (See *Note replication-options::.) This
filtered log is provided to the slave.

The dummy process does not actually store any data, so there is little
processing overhead incurred by running the additional *Note `mysqld':
mysqld. process on the replication master host.  This type of setup can
be repeated with additional replication slaves.

*Note `INSERT': insert. triggers for `BLACKHOLE' tables work as
expected. However, because the `BLACKHOLE' table does not actually
store any data, *Note `UPDATE': update. and *Note `DELETE': delete.
triggers are not activated: The `FOR EACH ROW' clause in the trigger
definition does not apply because there are no rows.

Other possible uses for the `BLACKHOLE' storage engine include:

   * Verification of dump file syntax.

   * Measurement of the overhead from binary logging, by comparing
     performance using `BLACKHOLE' with and without binary logging
     enabled.

   * `BLACKHOLE' is essentially a `no-op' storage engine, so it could
     be used for finding performance bottlenecks not related to the
     storage engine itself.

*Blackhole Engine and Auto Increment Columns*

The Blackhole engine is a no-op engine. Any operations performed on a
table using Blackhole will have no effect. This should be born in mind
when considering the behavior of primary key columns that auto
increment. The engine will not automatically increment field values,
and does not retain auto increment field state. This has important
implications in replication.

Consider the following replication scenario where all three of the
following conditions apply:

  1. On a master server there is a blackhole table with an auto
     increment field that is a primary key.

  2. On a slave the same table exists but using the MyISAM engine.

  3. Inserts are performed into the master's table without explicitly
     setting the auto increment value in the `INSERT' statement itself
     or through using a `SET INSERT_ID' statement.

In this scenario replication will fail with a duplicate entry error on
the primary key column.

In statement based replication, the value of `INSERT_ID' in the context
event will always be the same. Replication will therefore fail due to
trying insert a row with a duplicate value for a primary key column.

In row based replication, the value that the engine returns for the row
always be the same for each insert. This will result in the slave
attempting to replay two insert log entries using the same value for
the primary key column, and so replication will fail.


File: manual.info,  Node: ha-overview,  Next: replication,  Prev: storage-engines,  Up: Top

15 High Availability and Scalability
************************************

* Menu:

* ha-ovm-template::              Oracle VM Template for MySQL Enterprise Edition
* ha-drbd::                      Using MySQL with DRBD
* ha-heartbeat::                 Using Linux HA Heartbeat
* ha-vm::                        Using MySQL within an Amazon EC2 Instance
* ha-zfs-replication::           Using ZFS Replication
* ha-memcached::                 Using MySQL with `memcached'
* mysql-proxy::                  MySQL Proxy

MySQL is deployed into many applications demanding availability and
scalability.

Availability refers to the ability to cope with, and if necessary
recover from, failures on the host, including failures of MySQL, the
operating system, or the hardware and maintenance activity that may
otherwise cause downtime. Scalability refers to the ability to spread
both the database and the load of your application queries across
multiple MySQL servers.

Because each application has different operational and availability
requirements, MySQL offers a range of certified and supported
solutions, delivering the appropriate levels of High Availability (HA)
and scalability to meet service level requirements. Such solutions
extend from replication, through virtualization and geographically
redundant, multi-data center solutions delivering 99.999% uptime.

Selecting the right high availability solution for an application
largely depends on:

   * The level of availability required.

   * The type of application being deployed.

   * Accepted best practices within your own environment.

The primary solutions supported by MySQL include:

   * MySQL Replication. Learn more:
     `http://dev.mysql.com/doc/refman/5.5/en/replication.html'

   * MySQL Cluster. Learn more:
     `http://dev.mysql.com/doc/refman/5.1/en/mysql-cluster.html'

   * Oracle VM Template for MySQL. Learn more: *Note ha-ovm-template::.

Further options are available using third-party solutions such as DRBD
(Distributed Replicated Block Device) and Heartbeat, and more complex
scenarios can be solved through a combination of these technologies.

Each architecture used to achieve highly available database services is
differentiated by the levels of uptime it offers. These architectures
can be grouped into three main categories:

   * Data Replication.

   * Clustered & Virtualized Systems.

   * Shared-Nothing, Geographically-Replicated Clusters.

As illustrated in the following figure, each of these architectures
offers progressively higher levels of uptime, which must be balanced
against potentially greater levels of cost and complexity that each can
incur. Simply deploying a high availability architecture is not a
guarantee of actually delivering HA. In fact, a poorly implemented and
maintained shared-nothing cluster could easily deliver lower levels of
availability than a simple data replication solution.

FIGURE GOES HERE: Tradeoffs: Cost and Complexity versus Availability

The following figure maps common application types to architectures,
based on best practices observed from the MySQL user base. It serves as
a reference point to investigate which HA architectures can best serve
your requirements.

FIGURE GOES HERE: High Availability Architectures for Common
Application Types

The following table compares the HA and Scalability capabilities of the
various MySQL solutions:

Requirement    MySQL        MySQL        Heartbeat +  Oracle VM    MySQL
               Replication  Replication  DRBD         Template     Cluster
                            + Linux                                
                            Heartbeat                              
*Availability*                                                     
Platform       All          Linux        Linux        Oracle Linux All
Support        Supported                                           Supported
               by MySQL                                            by MySQL
               Server                                              Cluster
               (http://www.mysql.com/support/supportedplatforms/database.html)                                       (http://www.mysql.com/support/supportedplatforms/cluster.html)
Automated IP   No           Yes          Yes          Yes          Depends on
Failover                                                           Connector
                                                                   and
                                                                   Configuration
Automated      No           No           Yes          Yes          Yes
Database                                                           
Failover                                                           
Automatic      No           No           Yes          N/A -        Yes
Data                                                  Shared       
Resynchronization                                       Storage      
Typical        User /       ConfigurationConfigurationConfiguration1 Second
Failover Time  Script       Dependent,   Dependent,   Dependent,   and Less
               Dependent    60 seconds   60 seconds   60 seconds   
                            and Above    and Above    and Above    
Synchronous    No,          No,          Yes          N/A -        Yes
Replication    Asynchronous Asynchronous              Shared       
               and          and                       Storage      
               SemisynchronousSemisynchronous                          
Shared Storage No,          No,          No,          Yes          No,
               Distributed  Distributed  Distributed               Distributed
Geographic     Yes          Yes          Yes, via     Yes, via     Yes, via
redundancy                               MySQL        MySQL        MySQL
support                                  Replication  Replication  Replication
Update Schema  No           No           No           No           Yes
On-Line                                                            
*Scalability*                                                      
Number of      One Master,  One Master,  One Active   One Active   255
Nodes          Multiple     Multiple     (primary),   (primary),   
               Slaves       Slaves       one Passive  one Passive  
                                         (secondary)  (secondary)  
                                         Node         Node         
Built-in Load  Reads, via   Reads, via   Reads, via   Reads, via   Yes, Reads
Balancing      MySQL        MySQL        MySQL        MySQL        and Writes
               Replication  Replication  Replication  Replication  
                                                      & During     
                                                      Failover     
Supports       Yes          Yes          Yes          Yes          Yes
Read-Intensive                                                     
Workloads                                                          
Supports       Yes, via     Yes, via     Yes, via     Yes, via     Yes, via
Write-IntensiveApplication-LevelApplication-LevelApplication-LevelApplication-LevelAuto-Sharding
Workloads      Sharding     Sharding     Sharding to  Sharding to  
                                         Multiple     Multiple     
                                         Active/PassiveActive/Passive
                                         Pairs        Pairs        
Scale On-Line  No           No           No           No           Yes
(add nodes,                                                        
repartition,                                                       
etc.)                                                              


File: manual.info,  Node: ha-ovm-template,  Next: ha-drbd,  Prev: ha-overview,  Up: ha-overview

15.1 Oracle VM Template for MySQL Enterprise Edition
====================================================

Virtualization is a key technology to enable data center efficiency and
high availability while providing the foundation for cloud computing.
Integrating MySQL Enterprise Edition with Oracle Linux, the Oracle VM
Template is the fastest, easiest, and most reliable way to provision
virtualized MySQL instances, enabling users to meet the explosive
demand for highly available services.

The Oracle VM Template enables rapid deployment and eliminates manual
configuration efforts. It provides a pre-installed and pre-configured
virtualized MySQL 5.5 Enterprise Edition software image running on
Oracle Linux and Oracle VM, certified for production use. The MySQL
software image has undergone extensive integration and quality
assurance testing as part of the development process.

In addition to rapid provisioning, MySQL users also benefit from the
integrated high availability features of Oracle VM which are designed
to enable organizations to meet stringent SLA (Service Level Agreement)
demands through a combination of:

   * *Automatic recovery from failures*, with Oracle VM automatically
     restarting failed instances on available servers in the server
     pool after outages of the physical server, VM or MySQL database.

   * *Live Migration*, enabling operations staff to move running
     instances of MySQL to alternative hosts within a server pool
     during maintenance operations.

Instructions for the creation, deployment and use of the Oracle VM
Template for MySQL Enterprise Edition are available from:

   * The Oracle VM Template for MySQL Enterprise Edition whitepaper:
     `http://www.mysql.com/why-mysql/white-papers/mysql_wp_oracle-vm-template-for-mee.php'.

   * The README file accompanying the download of the Template.

To download the Oracle VM Template for MySQL Enterprise, go to
`http://edelivery.oracle.com/oraclevm' and follow these instructions:

   * Complete your registration information (Name, Company Name, Email
     Address and Country) and click on the download agreement.

   * Select "Oracle VM Templates" from the "Select a Product Pack"
     pull-down menu and click "Go".

   * Select MySQL Enterprise from the list of Oracle VM Templates.

   * Download and unzip the files and refer to the README for further
     instructions.


File: manual.info,  Node: ha-drbd,  Next: ha-heartbeat,  Prev: ha-ovm-template,  Up: ha-overview

15.2 Using MySQL with DRBD
==========================

* Menu:

* ha-drbd-install::              Configuring the DRBD Environment
* ha-drbd-install-mysql::        Configuring MySQL for DRBD
* ha-drbd-performance::          Optimizing Performance and Reliability

The Distributed Replicated Block Device (DRBD) is a Linux Kernel module
that constitutes a distributed storage system. You can use DRBD to
share block devices between Linux servers and, in turn, share file
systems and data.

DRBD implements a block device which can be used for storage and which
is replicated from a primary server to one or more secondary servers.
The distributed block device is handled by the DRBD service. Writes to
the DRBD block device are distributed among the servers. Each DRBD
service writes the information from the DRBD block device to a local
physical block device (hard disk).

On the primary data writes are written both to the underlying physical
block device and distributed to the secondary DRBD services. On the
secondary, the writes received through DRBD and written to the local
physical block device. On both the primary and the secondary, reads
from the DRBD block device are handled by the underlying physical block
device. The information is shared between the primary DRBD server and
the secondary DRBD server synchronously and at a block level, and this
means that DRBD can be used in high-availability solutions where you
need failover support.

FIGURE GOES HERE: DRBD Architecture Overview

When used with MySQL, DRBD can be used to ensure availability in the
event of a failure. MySQL is configured to store information on the
DRBD block device, with one server acting as the primary and a second
machine available to operate as an immediate replacement in the event
of a failure.

For automatic failover support, you can combine DRBD with the Linux
Heartbeat project, which manages the interfaces on the two servers and
automatically configures the secondary (passive) server to replace the
primary (active) server in the event of a failure. You can also combine
DRBD with MySQL Replication to provide both failover and scalability
within your MySQL environment.

For information on how to configure DRBD and MySQL, including Heartbeat
support, see *Note ha-drbd-install::.

For FAQs about using DRBD and MySQL, see *Note
faqs-mysql-drbd-heartbeat::.

*Note*:

Because DRBD is a Linux Kernel module, it is currently not supported on
platforms other than Linux.


File: manual.info,  Node: ha-drbd-install,  Next: ha-drbd-install-mysql,  Prev: ha-drbd,  Up: ha-drbd

15.2.1 Configuring the DRBD Environment
---------------------------------------

* Menu:

* ha-drbd-install-os::           Setting Up Your Operating System for DRBD
* ha-drbd-install-drbd::         Installing and Configuring DRBD
* ha-drbd-install-drbd-primary::  Setting Up a DRBD Primary Node
* ha-drbd-install-drbd-secondary::  Setting Up a DRBD Secondary Node
* ha-drbd-install-drbd-using::   Monitoring a DRBD Device
* ha-drbd-install-drbd-management::  Managing a DRBD Installation
* ha-drbd-install-drbd-othercfg::  Additional DRBD Configuration Options

To set up DRBD, MySQL, and Heartbeat, you follow a number of steps that
affect the operating system, DRBD and your MySQL installation.

Before starting the installation process, be aware of the following
information, terms and requirements on using DRBD:

   * DRBD works through two (or more) servers, each called a _node_.

   * Ensure that your DRBD nodes are as identically configured as
     possible, so that the secondary machine can act as a direct
     replacement for the primary machine in the event of system failure.

   * The node that contains the primary data, has read/write access to
     the data, and in an HA environment is the currently active node is
     called the _primary_.

   * The server to which the data is replicated is called the
     _secondary_.

   * A collection of nodes that are sharing information is referred to
     as a _DRBD cluster_.

   * For DRBD to operate, you must have a block device on which the
     information can be stored on _each_ DRBD node. The lower-level
     block device can be a physical disk partition, a partition from a
     volume group or RAID device or any other block device.

     Typically, you use a spare partition on which the physical data is
     stored. On the primary node, this disk holds the raw data that you
     want replicated. On the secondary nodes, the disk holds the data
     replicated to the secondary server by the DRBD service. Ideally,
     the size of the partition on the two DRBD servers should be
     identical, but this is not necessary as long as there is enough
     space to hold the data that you want distributed between the two
     servers.

   * For the distribution of data to work, DRBD is used to create a
     logical block device that uses the lower level block device for
     the actual storage of information. To store information on the
     distributed device, a file system is created on the DRBD logical
     block device.

   * When used with MySQL, once the file system has been created, you
     move the MySQL data directory (including InnoDB data files and
     binary logs) to the new file system.

   * When you set up the secondary DRBD server, you set up the physical
     block device and the DRBD logical block device that stores the
     data. The block device data is then copied from the primary to the
     secondary server.

The overview for the installation and configuration sequence is as
follows:

  1. First, set up your operating system and environment. This includes
     setting the correct host name, updating the system and preparing
     the available packages and software required by DRBD, and
     configuring a physical block device to be used with the DRBD block
     device. See *Note ha-drbd-install-os::.

  2. Installing DRBD requires installing or compiling the DRBD source
     code and then configuring the DRBD service to set up the block
     devices to be shared. See *Note ha-drbd-install-drbd::.

  3. After configuring DRBD, alter the configuration and storage
     location of the MySQL data, as explained in *Note
     ha-drbd-install-mysql::.

Optionally, configure high availability using the Linux Heartbeat
service. See *Note ha-heartbeat::, for more information.


File: manual.info,  Node: ha-drbd-install-os,  Next: ha-drbd-install-drbd,  Prev: ha-drbd-install,  Up: ha-drbd-install

15.2.1.1 Setting Up Your Operating System for DRBD
..................................................

To set your Linux environment for using DRBD, follow these system
configuration steps:

   * Make sure that the primary and secondary DRBD servers have the
     correct host name, and that the host names are unique.  You can
     verify this by using the `uname' command:

          shell> uname -n
          drbd-one

     If the host name is not set correctly, edit the appropriate file
     (usually `/etc/sysconfig/network', `/etc/hostname', or
     `/etc/conf.d/hostname') and set the name correctly.

   * Each DRBD node must have a unique IP address. Make sure that the
     IP address information is set correctly within the network
     configuration and that the host name and IP address has been set
     correctly within the `/etc/hosts' file.

   * Although you can rely on the DNS or NIS system for host resolving,
     in the event of a major network failure these services may not be
     available. If possible, add the IP address and host name of each
     DRBD node into the `/etc/hosts' file for each machine. This
     ensures that the node information can always be determined even if
     the DNS/NIS servers are unavailable.

   * As a general rule, the faster your network connection the better.
     Because the block device data is exchanged over the network,
     everything that is written to the local disk on the DRBD primary
     is also written to the network for distribution to the DRBD
     secondary.

     For tips on configuring a faster network connection, see *Note
     ha-drbd-performance::.

   * You devote a spare disk, or a partition on an existing disk, as
     the physical storage location for the DRBD data that is replicated.

     If the disk is unpartitioned, partition the disk using `fdisk',
     `cfdisk' or other partitioning solution. Do not create a file
     system on the new partition.

     You must have a physical disk available for the storage of the
     replicated information on each DRBD node. Ensure that the physical
     partition on the DRBD secondary is at least as big as the
     partitions on the DRBD primary node. If possible, use identical
     sizes for the partitions on each node.

   * If possible, upgrade your system to the latest available Linux
     kernel for your distribution. Once the kernel has been installed,
     you must reboot to make the kernel active. To use DRBD, you must
     also install the relevant kernel development and header files that
     are required for building kernel modules. Platform specification
     information for this is available later in this section.

Before you compile or install DRBD, make sure the following tools and
files are in place:

   * Kernel header files.

   * Kernel source files.

   * GCC Compiler.

   * `glib 2' library.

   * `flex' command.

Here are some operating system specific tips for setting up your
installation:

   * *Tips for Red Hat (including CentOS and Fedora)*:

     Use `up2date' or `yum' to update and install the latest kernel and
     kernel header files:

          root-shell> up2date kernel-smp-devel kernel-smp

     Reboot. If you are going to build DRBD from source, then update
     your system with the required development packages:

          root-shell> up2date glib-devel openssl-devel libgcrypt-devel glib2-devel \
          pkgconfig ncurses-devel rpm-build rpm-devel redhat-rpm-config gcc \
          gcc-c++ bison flex gnutls-devel lm_sensors-devel net-snmp-devel \
          python-devel bzip2-devel libselinux-devel perl-DBI

     If you are going to use the pre-built DRBD RPMs:

          root-shell> up2date gnutls lm_sensors net-snmp ncurses libgcrypt glib2 openssl glib

   * *Tips for Debian, Ubuntu, Kubuntu*:

     Use `apt-get' to install the kernel packages

          root-shell> apt-get install linux-headers linux-image-server

     If you are going to use the pre-built Debian packages for DRBD,
     you do not need any additional packages.

     To build DRBD from source, use the following command to install
     the required components:

          root-shell> apt-get install devscripts flex bison build-essential \
          dpkg-dev kernel-package debconf-utils dpatch debhelper \
          libnet1-dev e2fslibs-dev libglib2.0-dev automake1.9 \
          libgnutls-dev libtool libltdl3 libltdl3-dev

   * *Tips for Gentoo*:

     Gentoo is a source based Linux distribution and therefore many of
     the source files and components that you need are either already
     installed or are installed automatically by `emerge'.

     To install DRBD 0.8.x, you must unmask the `sys-cluster/drbd'
     build by adding the following line to
     `/etc/portage/package.keywords':

          sys-cluster/drbd ~x86
          sys-cluster/drbd-kernel ~x86

     To enable the DRBD kernel module, you must rebuild your kernel,
     although the method depends on the kernel version you are using.
     Determine your current kernel version using `uname -a'.

        * For Linux kernels lower than 2.6.33, enable the userspace
          kernelspace linker to build and load the DRBD kernel driver.
          To enable the kernelspace linker, rebuild the kernel with
          this option. The best way to do this is to use `genkernel'
          with the `--menuconfig' option to select the option and then
          rebuild the kernel. For example, at the command line as
          `root':

               root-shell> genkernel --menuconfig all

          Then through the menu options, select `Device Drivers',
          `Connector - unified userspace <-> kernelspace linker' and
          finally press 'y' or 'space' to select the `Connector -
          unified userspace <-> kernelspace linker' option. After you
          exit the menu configuration, the kernel is rebuilt and
          installed.  If this is a new kernel, update your bootloader
          to point to the kernel if the kernel version is different than
          your current kernel version. Now reboot to enable the new
          kernel.

        * For Linux Kernel 2.6.33 and later, DRBD is included within
          the kernel sources. To enable the DRBD module you must
          rebuild your kernel. The best way to do this is to use
          `genkernel' with the `--menuconfig' option to select the
          option and then rebuild the kernel. For example, at the
          command line as `root':

               root-shell> genkernel --menuconfig all

          Then through the menu options, select `Device Drivers',
          `Block Devices', and then `DRBD Distributed Replicated Block
          Device support'. After you exit the menu configuration, the
          kernel is rebuilt and installed. If this is a new kernel,
          update your bootloader to point to the kernel if the kernel
          version is different than your current kernel version. Now
          reboot to enable the new kernel.


File: manual.info,  Node: ha-drbd-install-drbd,  Next: ha-drbd-install-drbd-primary,  Prev: ha-drbd-install-os,  Up: ha-drbd-install

15.2.1.2 Installing and Configuring DRBD
........................................

To install DRBD, you can choose either the pre-built binary
installation packages, or you can use the source packages and build
from source. To build from source, you must have installed the source
and development packages.

To install using a binary distribution, ensure that the kernel version
number of the binary package matches your currently active kernel. You
can use `uname' to find out this information:

     shell> uname -r
     2.6.20-gentoo-r6

Once DRBD has been built and installed, edit the `/etc/drbd.conf' file
and then run a number of commands to build the block device and set up
the replication.

Although the steps below are split into those for the primary node and
the secondary node, the configuration files for all nodes should be
identical, and many of the same steps have to be repeated on each node
to enable the DRBD block device.

Building from source:

To download and install from the source code:

  1. Download the source code.

  2. Unpack the package:

          shell> tar zxf drbd-8.3.0.tar.gz

  3. Change to the extracted directory, and then run `make' to build
     the DRBD driver:

          shell> cd drbd-8.3.0
          shell> make

  4. Install the kernel driver and commands:

          shell> make install

Binary Installation:

   * * SUSE Linux Enterprise Server (SLES)*

     For SUSE, use `yast':

          shell> yast -i drbd

     Alternatively:

          shell> rug install drbd

   * *Debian*

     Use `apt-get' to install the modules. You do not need to install
     any other components.

          shell> apt-get install drbd8-utils drbd8-module

   * *Debian 3.1 and 4.0*

     You must install the `module-assistant' to build the DRBD kernel
     module, in addition to the DRBD components.

          shell> apt-get install drbd0.7-utils drbd0.7-module-source \
            build-essential module-assistant
          shell> module-assistant auto-install drbd0.7

   * *CentOS*

     DRBD can be installed using `yum':

          shell> yum install drbd kmod-drbd

   * *Ubuntu*

     Enable the universe component for your preferred Ubuntu mirror in
     `/etc/apt/sources.list', then issue these commands:

          shell> apt-get update
          shell> apt-get install drbd8-utils drbd8-module-source \
            build-essential module-assistant
          shell> module-assistant auto-install drbd8

   * *Gentoo*

     You can now `emerge' DRBD 0.8.x into your Gentoo installation:

          root-shell> emerge drbd

     Once `drbd' is downloaded and installed, decompress and copy the
     default configuration file from
     `/usr/share/doc/drbd-8.0.7/drbd.conf.bz2' into `/etc/drbd.conf'.


File: manual.info,  Node: ha-drbd-install-drbd-primary,  Next: ha-drbd-install-drbd-secondary,  Prev: ha-drbd-install-drbd,  Up: ha-drbd-install

15.2.1.3 Setting Up a DRBD Primary Node
.......................................

To set up a DRBD primary node, configure the DRBD service, create the
first DRBD block device, and then create a file system on the device so
that you can store files and data.

The DRBD configuration file `/etc/drbd.conf' defines a number of
parameters for your DRBD configuration, including the frequency of
updates and block sizes, security information and the definition of the
DRBD devices that you want to create.

The key elements to configure are the `on' sections which specify the
configuration of each node.

To follow the configuration, the sequence below shows only the changes
from the default `drbd.conf' file.  Configurations within the file can
be both global or tied to specific resource.

  1. Set the synchronization rate between the two nodes. This is the
     rate at which devices are synchronized in the background after a
     disk failure, device replacement or during the initial setup. Keep
     this in check compared to the speed of your network connection.
     Gigabit Ethernet can support up to 125 MB/second, 100Mbps Ethernet
     slightly less than a tenth of that (12MBps). If you are using a
     shared network connection, rather than a dedicated, then gauge
     accordingly.

     To set the synchronization rate, edit the `rate' setting within the
     `syncer' block:

          syncer {
              rate 10M;
          }

     You may additionally want to set the `al-extents' parameter. The
     default for this parameter is 257.

     For more detailed information on synchronization, the effects of
     the synchronization rate and the effects on network performance,
     see *Note ha-drbd-performance-syncrate::.

  2. Set up some basic authentication. DRBD supports a simple password
     hash exchange mechanism. This helps to ensure that only those
     hosts with the same shared secret are able to join the DRBD node
     group.

          cram-hmac-alg "sha1";
          shared-secret "SHARED-STRING";

  3. Now you must configure the host information. You must have the
     node information for the primary and secondary nodes in the
     `drbd.conf' file on each host.  Configure the following
     information for each node:

        * `device': The path of the logical block device that is
          created by DRBD.

        * `disk': The block device that stores the data.

        * `address': The IP address and port number of the host that
          holds this DRBD device.

        * `meta-disk': The location where the metadata about the DRBD
          device is stored. If you set this to `internal', DRBD uses the
          physical block device to store the information, by recording
          the metadata within the last sections of the disk. The exact
          size depends on the size of the logical block device you have
          created, but it may involve up to 128MB.

     A sample configuration for our primary server might look like this:

          on drbd-one {
          device /dev/drbd0;
          disk /dev/hdd1;
          address 192.168.0.240:8888;
          meta-disk internal;
          }

     The `on' configuration block should be repeated for the secondary
     node (and any further) nodes:

          on drbd-two {
          device /dev/drbd0;
          disk /dev/hdd1;
          address 192.168.0.241:8888;
          meta-disk internal;
          }

     The IP address of each `on' block must match the IP address of the
     corresponding host. Do not set this value to the IP address of the
     corresponding primary or secondary in each case.

  4. Before starting the primary node, create the metadata for the
     devices:

          root-shell> drbdadm create-md all

  5. You are now ready to start DRBD:

          root-shell> /etc/init.d/drbd start

     DRBD should now start and initialize, creating the DRBD devices
     that you have configured.

  6. DRBD creates a standard block device - to make it usable, you must
     create a file system on the block device just as you would with
     any standard disk partition. Before you can create the file
     system, you must mark the new device as the primary device (that
     is, where the data is written and stored), and initialize the
     device. Because this is a destructive operation, you must specify
     the command line option to overwrite the raw data:

          root-shell> drbdadm -- --overwrite-data-of-peer primary all

     If you are using a version of DRBD 0.7.x or earlier, then use a
     different command-line option:

          root-shell> drbdadm -- --do-what-I-say primary all

     Now create a file system using your chosen file system type:

          root-shell> mkfs.ext3 /dev/drbd0

  7. You can now mount the file system and if necessary copy files to
     the mount point:

          root-shell> mkdir /mnt/drbd
          root-shell> mount /dev/drbd0 /mnt/drbd
          root-shell> echo "DRBD Device" >/mnt/drbd/samplefile

Your primary node is now ready to use. Next, configure your secondary
node or nodes.


File: manual.info,  Node: ha-drbd-install-drbd-secondary,  Next: ha-drbd-install-drbd-using,  Prev: ha-drbd-install-drbd-primary,  Up: ha-drbd-install

15.2.1.4 Setting Up a DRBD Secondary Node
.........................................

The configuration process for setting up a secondary node is the same
as for the primary node, except that you do not have to create the file
system on the secondary node device, as this information is
automatically transferred from the primary node.

To set up a secondary node:

  1. Copy the `/etc/drbd.conf' file from your primary node to your
     secondary node. It should already contain all the information and
     configuration that you need, since you had to specify the
     secondary node IP address and other information for the primary
     node configuration.

  2. Create the DRBD metadata on the underlying disk device:

          root-shell> drbdadm create-md all

  3. Start DRBD:

          root-shell> /etc/init.d/drbd start

Once DRBD has started, it starts to copy the data from the primary node
to the secondary node. Even with an empty file system this takes some
time, since DRBD is copying the block information from a block device,
not simply copying the file system data.

You can monitor the progress of the copy between the primary and
secondary nodes by viewing the output of `/proc/drbd':

     root-shell> cat /proc/drbd
     version: 8.0.4 (api:86/proto:86)
     SVN Revision: 2947 build by root@drbd-one, 2007-07-30 16:43:05
      0: cs:SyncSource st:Primary/Secondary ds:UpToDate/Inconsistent C r---
         ns:252284 nr:0 dw:0 dr:257280 al:0 bm:15 lo:0 pe:7 ua:157 ap:0
             [==>.................] sync'ed: 12.3% (1845088/2097152)K
             finish: 0:06:06 speed: 4,972 (4,580) K/sec
             resync: used:1/31 hits:15901 misses:16 starving:0 dirty:0 changed:16
             act_log: used:0/257 hits:0 misses:0 starving:0 dirty:0 changed:0

You can monitor the synchronization process by using the `watch'
command to run the command at specific intervals:

     root-shell> watch -n 10 'cat /proc/drbd'


File: manual.info,  Node: ha-drbd-install-drbd-using,  Next: ha-drbd-install-drbd-management,  Prev: ha-drbd-install-drbd-secondary,  Up: ha-drbd-install

15.2.1.5 Monitoring a DRBD Device
.................................

Once the primary and secondary machines are configured and
synchronized, you can get the status information about your DRBD device
by viewing the output from `/proc/drbd':

     root-shell> cat /proc/drbd
     version: 8.0.4 (api:86/proto:86)
     SVN Revision: 2947 build by root@drbd-one, 2007-07-30 16:43:05
      0: cs:Connected st:Primary/Secondary ds:UpToDate/UpToDate C r---
         ns:2175704 nr:0 dw:99192 dr:2076641 al:33 bm:128 lo:0 pe:0 ua:0 ap:0
             resync: used:0/31 hits:134841 misses:135 starving:0 dirty:0 changed:135
             act_log: used:0/257 hits:24765 misses:33 starving:0 dirty:0 changed:33

The first line provides the version/revision and build information.

The second line starts the detailed status information for an
individual resource. The individual field headings are as follows:

   * cs: connection state

   * st: node state (local/remote)

   * ld: local data consistency

   * ds: data consistency

   * ns: network send

   * nr: network receive

   * dw: disk write

   * dr: disk read

   * pe: pending (waiting for ack)

   * ua: unack'd (still need to send ack)

   * al: access log write count

In the previous example, the information shown indicates that the nodes
are connected, the local node is the primary (because it is listed
first), and the local and remote data is up to date with each other.
The remainder of the information is statistical data about the device,
and the data exchanged that kept the information up to date.

You can also get the status information for DRBD by using the startup
script with the `status' option:

     root-shell> /etc/init.d/drbd status
      * status:  started
      * drbd driver loaded OK; device status: ...                                                                                      [ ok ]
     version: 8.3.0 (api:88/proto:86-89)
     GIT-hash: 9ba8b93e24d842f0dd3fb1f9b90e8348ddb95829 build by root@gentoo1.vmbear, 2009-03-14 23:00:06
      0: cs:Connected ro:Secondary/Secondary ds:UpToDate/UpToDate C r---
         ns:0 nr:0 dw:0 dr:8385604 al:0 bm:0 lo:0 pe:0 ua:0 ap:0 ep:1 wo:b oos:0

The information and statistics are the same.


File: manual.info,  Node: ha-drbd-install-drbd-management,  Next: ha-drbd-install-drbd-othercfg,  Prev: ha-drbd-install-drbd-using,  Up: ha-drbd-install

15.2.1.6 Managing a DRBD Installation
.....................................

For administration, the main command is `drbdadm'. There are a number
of commands supported by this tool that control the connectivity and
status of the DRBD devices.

*Note*:

For convenience, a bash completion script provides tab completion for
options to `drbdadm'. The file `drbdadm.bash_completion' can be found
within the standard DRBD source package within the `scripts' directory.
To enable, copy the file to `/etc/bash_completion.d/drbdadm'.  You can
load it manually by using:

     shell> source /etc/bash_completion.d/drbdadm

The most common commands are those to set the primary/secondary status
of the local device. You can manually set this information for a number
of reasons, including to check the physical status of the secondary
device (since you cannot mount a DRBD device in primary mode), or when
you are temporarily moving the responsibility of keeping the data in
check to a different machine (for example, during an upgrade or physical
move of the normal primary node). You can set state of all local device
to be the primary using this command:

     root-shell> drbdadm primary all

Or switch the local device to be the secondary using:

     root-shell> drbdadm secondary all

To change only a single DRBD resource, specify the resource name
instead of `all'.

You can temporarily disconnect the DRBD nodes:

     root-shell> drbdadm disconnect all

Reconnect them using `connect':

     root-shell> drbdadm connect all

For other commands and help with `drbdadm' see the DRBD documentation.


File: manual.info,  Node: ha-drbd-install-drbd-othercfg,  Prev: ha-drbd-install-drbd-management,  Up: ha-drbd-install

15.2.1.7 Additional DRBD Configuration Options
..............................................

Additional options you can configure:

   * `protocol': Specifies the level of consistency to be used when
     information is written to the block device. The option is similar
     in principle to the `innodb_flush_log_at_trx_commit' option within
     MySQL. Three levels are supported:

        * `A': Data is considered written when the information reaches
          the TCP send buffer and the local physical disk. There is no
          guarantee that the data has been written to the remote server
          or the remote physical disk.

        * `B': Data is considered written when the data has reached the
          local disk and the remote node's network buffer. The data has
          reached the remote server, but there is no guarantee it has
          reached the remote server's physical disk.

        * `C': Data is considered written when the data has reached the
          local disk and the remote node's physical disk.

     The preferred and recommended protocol is C, as it is the only
     protocol which ensures the consistency of the local and remote
     physical storage.

   * `size': To use less than the entire partition space with your DRBD
     block device, specify the size of the DRBD device to be created.
     The size specification can include a quantifier. For example, to
     set the maximum size of the DRBD partition to 1GB, you would use:

          size 1G;

With the configuration file suitably configured and ready to use, now
populate the lower-level device with the metadata information, and then
start the DRBD service.


File: manual.info,  Node: ha-drbd-install-mysql,  Next: ha-drbd-performance,  Prev: ha-drbd-install,  Up: ha-drbd

15.2.2 Configuring MySQL for DRBD
---------------------------------

Once you have configured DRBD and have an active DRBD device and file
system, you can configure MySQL to use the chosen device to store the
MySQL data.

When performing a new installation of MySQL, you can either select to
install MySQL entirely onto the DRBD device, or just configure the data
directory to be located on the new file system.

In either case, the files and installation must take place on the
primary node, because that is the only DRBD node on which you can mount
the DRBD device file system as read/write.

Store the following files and information on your DRBD device:

   * MySQL data files, including the binary log, and InnoDB data files.

   * MySQL configuration file (`my.cnf').

To set up MySQL to use your new DRBD device and file system:

  1. If you are migrating an existing MySQL installation, stop MySQL:

          shell> mysqladmin shutdown

  2. Copy the `my.cnf' onto the DRBD device. If you are not already
     using a configuration file, copy one of the sample configuration
     files from the MySQL distribution.

          root-shell> mkdir /mnt/drbd/mysql
          root-shell> cp /etc/my.cnf /mnt/drbd/mysql

  3. Copy your MySQL data directory to the DRBD device and mounted file
     system.

          root-shell> cp -R /var/lib/mysql /drbd/mysql/data

  4. Edit the configuration file to reflect the change of directory by
     setting the value of the `datadir' option. If you have not already
     enabled the binary log, also set the value of the `log-bin' option.

          datadir = /drbd/mysql/data
            log-bin = mysql-bin

  5. Create a symbolic link from `/etc/my.cnf' to the new configuration
     file on the DRBD device file system.

          root-shell> ln -s /drbd/mysql/my.cnf /etc/my.cnf

  6. Now start MySQL and check that the data that you copied to the
     DRBD device file system is present.

          root-shell> /etc/init.d/mysql start

Your MySQL data should now be located on the file system running on
your DRBD device. The data is physically stored on the underlying
device that you configured for the DRBD device.  Meanwhile, the content
of your MySQL databases is copied to the secondary DRBD node.

Note that you cannot access the information on your secondary node, as
a DRBD device working in secondary mode is not available for use.


File: manual.info,  Node: ha-drbd-performance,  Prev: ha-drbd-install-mysql,  Up: ha-drbd

15.2.3 Optimizing Performance and Reliability
---------------------------------------------

* Menu:

* ha-drbd-performance-bonded::   Using Bonded Ethernet Network Interfaces
* ha-drbd-performance-syncrate::  Optimizing the Synchronization Rate

Because of the nature of the DRBD system, the critical requirements are
for a very fast exchange of the information between the two hosts. To
ensure that your DRBD setup is available to switch over in the event of
a failure as quickly as possible, you must transfer the information
between the two hosts using the fastest method available.

Typically, a dedicated network circuit should be used for exchanging
DRBD data between the two hosts. Use a separate, additional, network
interface for your standard network connection. For an example of this
layout, see *Note ha-drbd-performance-sepinterface::.

FIGURE GOES HERE: DRBD Architecture Using Separate Network Interfaces

The dedicated DRBD network interfaces should be configured to use a
nonrouted TCP/IP network configuration. For example, you might set the
primary to use 192.168.0.1 and the secondary 192.168.0.2.  These
networks and IP addresses should not be part of the normal network
subnet.

*Note*:

The preferred setup, whenever possible, is to use a direct cable
connection (using a crossover cable with Ethernet, for example) between
the two machines. This eliminates the risk of loss of connectivity due
to switch failures.


File: manual.info,  Node: ha-drbd-performance-bonded,  Next: ha-drbd-performance-syncrate,  Prev: ha-drbd-performance,  Up: ha-drbd-performance

15.2.3.1 Using Bonded Ethernet Network Interfaces
.................................................

For a set-up where there is a high-throughput of information being
written, consider using bonded network interfaces. This is where you
combine the connectivity of more than one network port, increasing the
throughput linearly according to the number of bonded connections.

Bonding also provides an additional benefit in that with multiple
network interfaces effectively supporting the same communications
channel, a fault within a single network interface in a bonded group
does not stop communication. For example, imagine you have a bonded
setup with four network interfaces providing a single interface channel
between two DRBD servers. If one network interface fails, communication
can continue on the other three without interruption, although at a
lower speed.

To enable bonded connections you must enable bonding within the kernel.
Then configure the module to specify the bonded devices and then
configure each new bonded device just as you would a standard network
device:

   * To configure the bonded devices, edit the `/etc/modprobe.conf'
     file (Red Hat) or add a file to the `/etc/modprobe.d' directory.
     In each case, you define the parameters for the kernel module.
     First, specify each bonding device:

          alias bond0 bonding

     You can then configure additional parameters for the kernel
     module. Typical parameters are the `mode' option and the `miimon'
     option.

     The `mode' option specifies how the network interfaces are used.
     The default setting is 0, which means that each network interface
     is used in a round-robin fashion (this supports aggregation and
     fault tolerance). Using setting 1 sets the bonding mode to
     active-backup. This means that only one network interface is used
     as a time, but that the link automatically fails over to a new
     interface if the primary interface fails. This settings only
     supports fault-tolerance.

     The `miimon' option enables the MII link monitoring. A positive
     value greater than zero indicates the monitoring frequency in
     milliseconds for checking each slave network interface that is
     configured as part of the bonded interface. A typical value is 100.

     You set th options within the module parameter file, and you must
     set the options for each bonded device individually:

          options bond0 miimon=100 mode=1

   * Reboot your server to enable the bonded devices.

   * Configure the network device parameters. This is a two-part
     process: set up the bonded device configuration, then configure
     the original network interfaces as 'slaves' of the new bonded
     interface.

        * For Red Hat Linux:

          Edit the configuration file for the bonded device. For device
          `bond0', this would be
          `/etc/sysconfig/network-scripts/ifcfg-bond0':

               DEVICE=bond0
               BOOTPROTO=none
               ONBOOT=yes
               GATEWAY=192.168.0.254
               NETWORK=192.168.0.0
               NETMASK=255.255.255.0
               IPADDR=192.168.0.1
               USERCTL=no

          Then for each network interface to be part of the bonded
          device, configure the interface as a slave to the 'master'
          bond. For example, the configuration of `eth0' in
          `/etc/sysconfig/network-scripts/ifcfg-eth0' might look like
          this::

               DEVICE=eth0
               BOOTPROTO=none
               HWADDR=00:11:22:33:44:55
               ONBOOT=yes
               TYPE=Ethernet
               MASTER=bond0
               SLAVE=yes

        * For Debian Linux:

          Edit the `/etc/iftab' file and configure the logical name and
          MAC address for each devices. For example:

               eth0 mac 00:11:22:33:44:55

          Now set the configuration of the devices in
          `/etc/network/interfaces':

               auto bond0
                   iface bond0 inet static
                   address 192.168.0.1
                   netmask 255.255.255.0
                   network 192.168.0.0
                   gateway 192.168.0.254
                   up /sbin/ifenslave bond0 eth0
                   up /sbin/ifenslave bond0 eth1

        * For Gentoo:

          Use `emerge' to add the `net-misc/ifenslave' package to your
          system.

          Edit the `/etc/conf.d/net' file and specify the network
          interface slaves in a bond, the dependencies and then the
          configuration for the bond itself. A sample configuration
          might look like this:

               slaves_bond0="eth0 eth1 eth2"

               config_bond0=( "192.168.0.1 netmask 255.255.255.0"  )

               depend_bond0() {
               need net.eth0 net.eth1 net.eth2
               }

          Then make sure that you add the new network interface to list
          of interfaces configured during boot:

               root-shell> rc-update add default net.bond0

Once the bonded devices are configured, reboot your systems.

You can monitor the status of a bonded connection using the `/proc'
file system:

     root-shell> cat /proc/net/bonding/bond0
     Bonding Mode: fault-tolerance (active-backup)
     Primary Slave: None
     Currently Active Slave: eth1
     MII Status: up
     MII Polling Interval (ms): 100
     Up Delay (ms): 200
     Down Delay (ms): 200
     Slave Interface: eth1
     MII Status: up
     Link Failure Count: 0
     Permanent HW addr: 00:11:22:33:44:55
     Slave Interface: eth2
     MII Status: up
     Link Failure Count: 0
     Permanent HW addr: 00:11:22:33:44:56


File: manual.info,  Node: ha-drbd-performance-syncrate,  Prev: ha-drbd-performance-bonded,  Up: ha-drbd-performance

15.2.3.2 Optimizing the Synchronization Rate
............................................

The `syncer rate' configuration parameter should be configured with
care as the synchronization rate can have a significant effect on the
performance of the DRBD setup in the event of a node or disk failure
where the information is being synchronized from the Primary to the
Secondary node.

In DRBD, there are two distinct ways of data being transferred between
peer nodes:

   * _Replication_ refers to the transfer of modified blocks being
     transferred from the primary to the secondary node. This happens
     automatically when the block is modified on the primary node, and
     the replication process uses whatever bandwidth is available over
     the replication link. The replication process cannot be throttled,
     because you want to transfer of the block information to happen as
     quickly as possible during normal operation.

   * _Synchronization_ refers to the process of bringing peers back in
     sync after some sort of outage, due to manual intervention, node
     failure, disk swap, or the initial setup. Synchronization is
     limited to the `syncer rate' configured for the DRBD device.

Both replication and synchronization can take place at the same time.
For example, the block devices can be synchronized while they are
actively being used by the primary node. Any I/O that updates on the
primary node automatically triggers replication of the modified block.
In the event of a failure within an HA environment, it is highly likely
that synchronization and replication will take place at the same time.

Unfortunately, if the synchronization rate is set too high, then the
synchronization process uses up all the available network bandwidth
between the primary and secondary nodes. In turn, the bandwidth
available for replication of changed blocks is zero, which stalls
replication and blocks I/O, and ultimately the application fails or
degrades.

To avoid enabling the `syncer rate' to consume the available network
bandwidth and prevent the replication of changed blocks, set the
`syncer rate' to less than the maximum network bandwidth.

Avoid setting the sync rate to more than 30% of the maximum bandwidth
available to your device and network bandwidth. For example, if your
network bandwidth is based on Gigabit ethernet, you should achieve
110MB/s. Assuming your disk interface is capable of handling data at
110MB/s or more, then the sync rate should be configured as `33M'
(33MB/s). If your disk system works at a rate lower than your network
interface, use 30% of your disk interface speed.

Depending on the application, you might limit the synchronization rate.
For example, on a busy server you could configure a significantly
slower synchronization rate to ensure the replication rate is not
affected.

The `al-extents' parameter controls the number of 4MB blocks of the
underlying disk that can be written to at the same time. Increasing
this parameter lowers the frequency of the metadata transactions
required to log the changes to the DRBD device, which in turn lowers
the number of interruptions in your I/O stream when synchronizing
changes. This can lower the latency of changes to the DRBD device.
However, if a crash occurs on your primary, then all of the blocks in
the activity log (that is, the number of `al-extents' blocks) must be
completely resynchronized before replication can continue.


File: manual.info,  Node: ha-heartbeat,  Next: ha-vm,  Prev: ha-drbd,  Up: ha-overview

15.3 Using Linux HA Heartbeat
=============================

* Menu:

* ha-heartbeat-config::          Heartbeat Configuration
* ha-heartbeat-drbd::            Using Heartbeat with MySQL and DRBD
* ha-heartbeat-drbd-dopd::       Using Heartbeat with DRBD and `dopd'
* ha-heartbeat-errors::          Dealing with System Level Errors

The Heartbeat program provides a basis for verifying the availability
of resources on one or more systems within a cluster.  In this context
a resource includes MySQL, the file systems on which the MySQL data is
being stored and, if you are using DRBD, the DRBD device being used for
the file system. Heartbeat also manages a virtual IP address, and the
virtual IP address should be used for all communication to the MySQL
instance.

A cluster within the context of Heartbeat is defined as two computers
notionally providing the same service. By definition, each computer in
the cluster is physically capable of providing the same services as all
the others in the cluster. However, because the cluster is designed for
high-availability, only one of the servers is actively providing the
service at any one time. Each additional server within the cluster is a
`hot-spare' that can be brought into service in the event of a failure
of the master, its next connectivity or the connectivity of the network
in general.

The basics of Heartbeat are very simple. Within the Heartbeat cluster
(see *Note ha-heartbeat-overview::, each machine sends a 'heartbeat'
signal to the other hosts in the cluster. The other cluster nodes
monitor this heartbeat. The heartbeat can be transmitted over many
different systems, including shared network devices, dedicated network
interfaces and serial connections.  Failure to get a heartbeat from a
node is treated as failure of the node. Although we do not know the
reason for the failure (it could be an OS failure, a hardware failure
in the server, or a failure in the network switch), it is safe to
assume that if no heartbeat is produced there is a fault.

FIGURE GOES HERE: Heartbeat Architecture

In addition to checking the heartbeat from the server, the system can
also check the connectivity (using `ping') to another host on the
network, such as the network router. This enables Heartbeat to detect a
failure of communication between a server and the router (and therefore
failure of the server, since it is no longer capable of providing the
necessary service), even if the heartbeat between the servers in the
clusters is working fine.

In the event of a failure, the resources on the failed host are
disabled, and the resources on one of the replacement hosts is enabled
instead. In addition, the Virtual IP address for the cluster is
redirected to the new host in place of the failed device.

When used with MySQL and DRBD, the MySQL data is replicated from the
master to the slave using the DRBD device, but MySQL is only running on
the master. When the master fails, the slave switches the DRBD devices
to be primary, the file systems on those devices are mounted, and MySQL
is started. The original master (if still available) has its resources
disabled, which means shutting down MySQL and unmounting the file
systems and switching the DRBD device to secondary.


File: manual.info,  Node: ha-heartbeat-config,  Next: ha-heartbeat-drbd,  Prev: ha-heartbeat,  Up: ha-heartbeat

15.3.1 Heartbeat Configuration
------------------------------

Heartbeat configuration requires three files located in `/etc/ha.d'.
The `ha.cf' contains the main heartbeat configuration, including the
list of the nodes and times for identifying failures.  `haresources'
contains the list of resources to be managed within the cluster. The
`authkeys' file contains the security information for the cluster.

The contents of these files should be identical on each host within the
Heartbeat cluster. It is important that you keep these files in sync
across all the hosts. Any changes in the information on one host should
be copied to the all the others.

For these examples n example of the `ha.cf' file is shown below:

     logfacility local0
     keepalive 500ms
     deadtime 10
     warntime 5
     initdead 30
     mcast bond0 225.0.0.1 694 2 0
     mcast bond1 225.0.0.2 694 1 0
     auto_failback off
     node drbd1
     node drbd2

The individual lines in the file can be identified as follows:

   * `logfacility': Sets the logging, in this case setting the logging
     to use `syslog'.

   * `keepalive': Defines how frequently the heartbeat signal is sent
     to the other hosts.

   * `deadtime'-- the delay in seconds before other hosts in the
     cluster are considered 'dead' (failed).

   * `warntime': The delay in seconds before a warning is written to
     the log that a node cannot be contacted.

   * `initdead': The period in seconds to wait during system startup
     before the other host is considered to be down.

   * `mcast': Defines a method for sending a heartbeat signal. In the
     above example, a multicast network address is being used over a
     bonded network device. If you have multiple clusters then the
     multicast address for each cluster should be unique on your
     network. Other choices for the heartbeat exchange exist, including
     a serial connection.

     If you are using multiple network interfaces (for example, one
     interface for your server connectivity and a secondary or bonded
     interface for your DRBD data exchange), use both interfaces for
     your heartbeat connection. This decreases the chance of a
     transient failure causing a invalid failure event.

   * `auto_failback': Sets whether the original (preferred) server
     should be enabled again if it becomes available. Switching this to
     `on' may cause problems if the preferred went offline and then
     comes back on line again. If the DRBD device has not been synced
     properly, or if the problem with the original server happens again
     you may end up with two different datasets on the two servers, or
     with a continually changing environment where the two servers
     flip-flop as the preferred server reboots and then starts again.

   * `node': Sets the nodes within the Heartbeat cluster group. There
     should be one `node' for each server.

An optional additional set of information provides the configuration
for a ping test that checks the connectivity to another host. Use this
to ensure that you have connectivity on the public interface for your
servers, so the ping test should be to a reliable host such as a router
or switch. The additional lines specify the destination machine for the
`ping', which should be specified as an IP address, rather than a host
name; the command to run when a failure occurs, the authority for the
failure and the timeout before an nonresponse triggers a failure. A
sample configure is shown below:

     ping 10.0.0.1
     respawn hacluster /usr/lib64/heartbeat/ipfail
     apiauth ipfail gid=haclient uid=hacluster
     deadping 5

In the above example, the `ipfail' command, which is part of the
Heartbeat solution, is called on a failure and 'fakes' a fault on the
currently active server. Configure the user and group ID under which
the command is executed (using the `apiauth'). The failure is triggered
after 5 seconds.

*Note*:

The `deadping' value must be less than the `deadtime' value.

The `authkeys' file holds the authorization information for the
Heartbeat cluster. The authorization relies on a single unique 'key'
that is used to verify the two machines in the Heartbeat cluster. The
file is used only to confirm that the two machines are in the same
cluster and is used to ensure that the multiple clusters can co-exist
within the same network.


File: manual.info,  Node: ha-heartbeat-drbd,  Next: ha-heartbeat-drbd-dopd,  Prev: ha-heartbeat-config,  Up: ha-heartbeat

15.3.2 Using Heartbeat with MySQL and DRBD
------------------------------------------

To use Heartbeat in combination with MySQL, use DRBD (see *Note
ha-drbd::) or another solution that enables sharing the MySQL database
files in event of a system failure. In these examples, DRBD is used as
the data sharing solution.

Heartbeat manages the configuration of different resources to manage
the switching between two servers in the event of a failure. The
resource configuration defines the individual services that should be
brought up (or taken down) in the event of a failure.

The `haresources' file within `/etc/ha.d' defines the resources that
should be managed, and the individual resource mentioned in this file in
turn relates to scripts located within `/etc/ha.d/resource.d'. The
resource definition is defined all on one line:

     drbd1 drbddisk Filesystem::/dev/drbd0::/drbd::ext3 mysql 10.0.0.100

The line is notionally split by whitespace. The first entry (`drbd1')
is the name of the preferred host; that is the server that is normally
responsible for handling the service. The last field is virtual IP
address or name that should be used to share the service. This is the
IP address that should be used to connect to the MySQL server. It is
automatically allocated to the server that is active when Heartbeat
starts.

The remaining fields between these two fields define the resources that
should be managed. Each Field should contain the name of the resource
(and each name should refer to a script within `/etc/ha.d/resource.d').
In the event of a failure, these resources are started on the backup
server by calling the corresponding script (with a single argument,
`start'), in order from left to right. If there are additional
arguments to the script, you can use a double colon to separate each
additional argument.

In the above example, we manage the following resources:

   * `drbddisk': The DRBD resource script, this switches the DRBD disk
     on the secondary host into primary mode, making the device
     read/write.

   * `Filesystem': Manages the Filesystem resource. In this case we
     have supplied additional arguments to specify the DRBD device,
     mount point and file system type.  When executed this should mount
     the specified file system.

   * `mysql': Manages the MySQL instances and starts the MySQL server.
     Copy the `mysql.resource' file from the `support-files' directory
     from any MySQL release into the `/etc/ha.d/resources.d' directory.

     If this file is not available in your distribution, you can use
     the following as the contents of the
     `/etc/ha.d/resource.d/mysql.resource' file:

          #!/bin/bash
          #
          # This script is inteded to be used as resource script by heartbeat
          #
          # Mar 2006 by Monty Taylor
          #
          ###

          . /etc/ha.d/shellfuncs

          case "$1" in
              start)
                  res=`/etc/init.d/mysql start`
                  ret=$?
                  ha_log $res
                  exit $ret
                  ;;
              stop)
                  res=`/etc/init.d/mysql stop`
                  ret=$?
                  ha_log $res
                  exit $ret
                  ;;
              status)
                  if [[ `ps -ef | grep '[m]ysqld'` > 1 ]] ; then
                     echo "running"
                  else
                     echo "stopped"
                  fi
                  ;;
              *)
                  echo "Usage: mysql {start|stop|status}"
                  exit 1
                  ;;
          esac

          exit 0

To be notified of the failure by email, add another line to the
`haresources' file with the address for warnings and the warning text:

     MailTo::youremail@address.com::DRBDFailure

With the Heartbeat configuration in place, copy the `haresources',
`authkeys' and `ha.cf' files from your primary and secondary servers to
make sure that the configuration is identical. Then start the Heartbeat
service, either by calling `/etc/init.d/heartbeat start' or by rebooting
both primary and secondary servers.

You can test the configuration by running a manual failover, connect to
the primary node and run:

     root-shell> /usr/lib64/heartbeat/hb_standby

This causes the current node to relinquish its resources cleanly to the
other node.


File: manual.info,  Node: ha-heartbeat-drbd-dopd,  Next: ha-heartbeat-errors,  Prev: ha-heartbeat-drbd,  Up: ha-heartbeat

15.3.3 Using Heartbeat with DRBD and `dopd'
-------------------------------------------

As a further extension to using DRBD and Heartbeat together, you can
enable `dopd'. The `dopd' daemon handles the situation where a DRBD
node is out of date compared to the master and prevents the slave from
being promoted to master in the event of a failure. This stops a
situation where you have two machines that have been masters ending up
different data on the underlying device.

For example, imagine that you have a two server DRBD setup, master and
slave. If the DRBD connectivity between master and slave fails, then
the slave is out of the sync with the master. If Heartbeat identifies a
connectivity issue for master and then switches over to the slave, the
slave DRBD device is promoted to the primary device, even though the
data on the slave and the master is not in synchronization.

In this situation, with `dopd' enabled, the connectivity failure
between the master and slave would be identified and the metadata on
the slave would be set to `Outdated'. Heartbeat refuses to switch over
to the slave even if the master failed. In a dual-host solution this
would effectively render the cluster out of action, as there is no
additional fail over server. In an HA cluster with three or more
servers, control would be passed to the slave that has an up to date
version of the DRBD device data.

To enable `dopd', modify the Heartbeat configuration and specify `dopd'
as part of the commands executed during the monitoring process. Add the
following lines to your `ha.cf' file:

     respawn hacluster /usr/lib/heartbeat/dopd
     apiauth dopd gid=haclient uid=hacluster

Make sure you make the same modification on both your primary and
secondary nodes.

Reload the Heartbeat configuration:

     root-shell> /etc/init.d/heartbeat reload

Modify your DRBD configuration by configuration the `outdate-peer'
option. Add the configuration line into the `common' section of
`/etc/drbd.conf' on both hosts. An example of the full block is shown
below:

     common {
       handlers {
         outdate-peer "/usr/lib/heartbeat/drbd-peer-outdater";
       }
     }

Finally, set the `fencing' option on your DRBD configured resources:

     resource my-resource {
       disk {
         fencing    resource-only;
       }
     }

Now reload your DRBD configuration:

     root-shell> drbdadmin adjust all

You can test the system by unplugging your DRBD link and monitoring the
output from `/proc/drbd'.


File: manual.info,  Node: ha-heartbeat-errors,  Prev: ha-heartbeat-drbd-dopd,  Up: ha-heartbeat

15.3.4 Dealing with System Level Errors
---------------------------------------

Because a kernel panic or oops may indicate potential problem with your
server, configure your server to remove itself from the cluster in the
event of a problem. Typically on a kernel panic, your system
automatically triggers a hard reboot. For a kernel oops, a reboot may
not happen automatically, but the issue that caused that oops may still
lead to potential problems.

You can force a reboot by setting the `kernel.panic' and
`kernel.panic_on_oops' parameters of the kernel control file
`/etc/sysctl.conf'. For example:

      kernel.panic_on_oops = 1
      kernel.panic = 1

You can also set these parameters during runtime by using the `sysctl'
command. You can either specify the parameters on the command line:

     shell> sysctl -w kernel.panic=1

Or you can edit your `sysctl.conf' file and then reload the
configuration information:

     shell> sysctl -p

Setting both these parameters to a positive value (representing the
number of seconds to wait before rebooting), causes the system to
reboot. Your second heartbeat node should then detect that the server
is down and then switch over to the failover host.


File: manual.info,  Node: ha-vm,  Next: ha-zfs-replication,  Prev: ha-heartbeat,  Up: ha-overview

15.4 Using MySQL within an Amazon EC2 Instance
==============================================

* Menu:

* ha-vm-aws-setup::              Setting Up MySQL on an EC2 AMI
* ha-vm-aws-instance::           EC2 Instance Limitations
* ha-vm-aws-deploy::             Deploying a MySQL Database Using EC2

The Amazon Elastic Compute Cloud (EC2) service provides virtual servers
that you can build and deploy to run a variety of different
applications and services, including MySQL. The EC2 service is based
around the Xen framework, supporting x86, Linux based, platforms with
individual instances of a virtual machine referred to as an Amazon
Machine Image (AMI). You have complete (root) access to the AMI
instance that you create, enabling you to configure and install your
AMI in any way you choose.

To use EC2, you create an AMI based on the configuration and
applications that you intend to use, and upload the AMI to the Amazon
Simple Storage Service (S3). From the S3 resource, you can deploy one
or more copies of the AMI to run as an instance within the EC2
environment. The EC2 environment provides management and control of the
instance and contextual information about the instance while it is
running.

Because you can create and control the AMI, the configuration, and the
applications, you can deploy and create any environment you choose.
This includes a basic MySQL server in addition to more extensive
replication, HA and scalability scenarios that enable you to take
advantage of the EC2 environment, and the ability to deploy additional
instances as the demand for your MySQL services and applications grow.

To aid the deployment and distribution of work, three different Amazon
EC2 instances are available, small (identified as `m1.small'), large
(`m1.large') and extra large (`m1.xlarge'). The different types provide
different levels of computing power measured in EC2 computer units
(ECU). A summary of the different instance configurations is shown here.

                   Small              Large              Extra Large
Platform           32-bit             64-bit             64-bit
CPU cores          1                  2                  4
ECUs               1                  4                  8
RAM                1.7GB              7.5GB              15GB
Storage            150GB              840GB              1680GB
I/O Performance    Medium             High               High

The typical model for deploying and using MySQL within the EC2
environment is to create a basic AMI that you can use to hold your
database data and application. Once the basic environment for your
database and application has been created you can then choose to deploy
the AMI to a suitable instance. Here the flexibility of having an AMI
that can be re-deployed from the small to the large or extra large EC2
instance makes it easy to upgrade the hardware environment without
rebuilding your application or database stack.

To get started with MySQL on EC2, including information on how to set
up and install MySQL within an EC2 installation and how to port and
migrate your data to the running instance, see *Note ha-vm-aws-setup::.

For tips and advice on how to create a scalable EC2 environment using
MySQL, including guides on setting up replication, see *Note
ha-vm-aws-deploy::.


File: manual.info,  Node: ha-vm-aws-setup,  Next: ha-vm-aws-instance,  Prev: ha-vm,  Up: ha-vm

15.4.1 Setting Up MySQL on an EC2 AMI
-------------------------------------

There are many different ways of setting up an EC2 AMI with MySQL,
including using any of the pre-configured AMIs supplied by Amazon.

The default _Getting Started_ AMI provided by Amazon uses Fedora Core
4, and you can install MySQL by using `yum':

     shell> yum install mysql

This installs both the MySQL server and the Perl DBD::mysql driver for
the Perl DBI API.

Alternatively, you can use one of the AMIs that include MySQL within
the standard installation.

Finally, you can also install a standard version of MySQL downloaded
from the MySQL Web site. The installation process and instructions are
identical to any other installation of MySQL on Linux. See *Note
installing::.

The standard configuration for MySQL places the data files in the
default location, `/var/lib/mysql'. The default data directory on an
EC2 instance is `/mnt' (although on the large and extra large instance
you can alter this configuration). You must edit `/etc/my.cnf' to set
the `datadir' option to point to the larger storage area.

*Important*:

The first time you use the main storage location within an EC2 instance
it needs to be initialized. The initialization process starts
automatically the first time you write to the device. You can start
using the device right away, but the write performance of the new
device is significantly lower on the initial writes until the
initialization process has finished.

To avoid this problem when setting up a new instance, you should start
the initialization process before populating your MySQL database. One
way to do this is to use `dd' to write to the file system:

     root-shell> dd if=/dev/zero of=initialize bs=1024M count=50

The preceding creates a 50GB on the file system and starts the
initialization process. Delete the file once the process has finished.

The initialization process can be time-consuming. On the small
instance, initialization takes between two and three hours. For the
large and extra large drives, the initialization can be 10 or 20 hours,
respectively.

In addition to configuring the correct storage location for your MySQL
data files, also consider setting the following other settings in your
instance before you save the instance configuration for deployment:

   * Set the MySQL server ID, so that when you use it for replication,
     the ID information is set correctly.

   * Enabling binary logging, so that replication can be initialized
     without starting and stopping the server.

   * Set the caching and memory parameters for your storage engines.
     There are no limitations or restrictions on what storage engines
     you use in your EC2 environment. Choose a configuration, possibly
     using one of the standard configurations provided with MySQL
     appropriate for the instance on which you expect to deploy. The
     large and extra large instances have RAM that can be dedicated to
     caching. Be aware that if you choose to install `memcached' on the
     servers as part of your application stack you must ensure there is
     enough memory for both MySQL and `memcached'.

Once you have configured your AMI with MySQL and the rest of your
application stack, save the AMI so that you can deploy and reuse the
instance.

Once you have your application stack configured in an AMI, populating
your MySQL database with data should be performed by creating a dump of
your database using `mysqldump', transferring the dump to the EC2
instance, and then reloading the information into the EC2 instance
database.

Before using your instance with your application in a production
situation, be aware of the limitations of the EC2 instance environment.
See *Note ha-vm-aws-instance::. To begin using your MySQL AMI, consult
the notes on deployment. See *Note ha-vm-aws-deploy::.


File: manual.info,  Node: ha-vm-aws-instance,  Next: ha-vm-aws-deploy,  Prev: ha-vm-aws-setup,  Up: ha-vm

15.4.2 EC2 Instance Limitations
-------------------------------

Be aware of the following limitations of the EC2 instances before
deploying your applications. Although these shouldn't affect your
ability to deploy within the Amazon EC2 environment, they may alter the
way you setup and configure your environment to support your
application.

   * Data stored within instances is not persistent. If you create an
     instance and populate the instance with data, then the data only
     remains in place while the machine is running, and does not
     survive a reboot. If you shut down the instance, any data it
     contained is lost.

     To ensure that you do not lose information, take regular backups
     using *Note `mysqldump': mysqldump. If the data being stored is
     critical, consider using replication to keep a `live' backup of
     your data in the event of a failure. When creating a backup, write
     the data to the Amazon S3 service to avoid the transfer charges
     applied when copying data offsite.

   * EC2 instances are not persistent. If the hardware on which an
     instance is running fails, the instance is shut down. This can
     lead to loss of data or service.

   * To replicate your EC2 instances to a non-EC2 environment, be aware
     of the transfer costs to and from the EC2 service. Data transfer
     between different EC2 instances is free, so using replication
     within the EC2 environment does not incur additional charges.

   * Certain HA features are either not directly supported, or have
     limiting factors or problems that could reduce their utility.  For
     example, using DRBD or MySQL Cluster might not work. The default
     storage configuration is also not redundant. You can use
     software-based RAID to improve redundancy, but this implies a
     further performance hit.


File: manual.info,  Node: ha-vm-aws-deploy,  Prev: ha-vm-aws-instance,  Up: ha-vm

15.4.3 Deploying a MySQL Database Using EC2
-------------------------------------------

Because you cannot guarantee the uptime and availability of your EC2
instances, when deploying MySQL within the EC2 environment, use an
approach that enables you to easily distribute work among your EC2
instances. There are a number of ways of doing this.  Using sharding
techniques, where you split the application across multiple servers
dedicating specific blocks of your dataset and users to different
servers is an effective way of doing this. As a general rule, it is
easier to create more EC2 instances to support more users than to
upgrade the instance to a larger machine.

The EC2 architecture works best when you treat the EC2 instances as
temporary, cache-based solutions, rather than as a long-term, high
availability solution. In addition to using multiple machines, take
advantage of other services, such as `memcached' to provide additional
caching for your application to help reduce the load on the MySQL
server so that it can concentrate on writes. On the large and extra
large instances within EC2, the RAM available can provide a large memory
cache for data.

Most types of scale-out topology that you would use with your own
hardware can be used and applied within the EC2 environment.  However,
use the limitations and advice already given to ensure that any
potential failures do not lose you any data. Also, because the relative
power of each EC2 instance is so low, be prepared to alter your
application to use sharding and add further EC2 instances to improve
the performance of your application.

For example, take the typical scale-out environment shown following,
where a single master replicates to one or more slaves (three in this
example), with a web server running on each replication slave.

Typical standard scale-out structure

You can reproduce this structure completely within the EC2 environment,
using an EC2 instance for the master, and one instance for each of the
web and MySQL slave servers.

*Note*:

Within the EC2 environment, internal (private) IP addresses used by the
EC2 instances are constant. Always use these internal addresses and
names when communicating between instances. Only use public IP
addresses when communicating with the outside world - for example, when
publicizing your application.

To ensure reliability of your database, add at least one replication
slave dedicated to providing an active backup and storage to the Amazon
S3 facility. You can see an example of this in the following topology.

Typical standard scale-out structure with backup using EC2

*Using `memcached'* within your EC2 instances should provide better
performance. The large and extra large instances have a significant
amount of RAM. To use `memcached' in your application, when loading
information from the database, first check whether the item exists in
the cache. If the data you are looking for exists in the cache, use it.
If not, reload the data from the database and populate the cache.

*Sharding* divides up data in your entire database by allocating
individual machines or machine groups to provide a unique set of data
according to an appropriate group. For example, you might put all users
with a surname ending in the letters A-D onto a single server. When a
user connects to the application and their surname is known, queries
can be redirected to the appropriate MySQL server.

When using sharding with EC2, separate the web server and MySQL server
into separate EC2 instances, and then apply the sharding decision logic
into your application. Once you know which MySQL server you should be
using for accessing the data you then distribute queries to the
appropriate server. You can see a sample of this in the following
illustration.

Using sharding in EC2 to spread the load

*Warning*:

With sharding and EC2, be careful that the potential for failure of an
instance does not affect your application. If the EC2 instance that
provides the MySQL server for a particular shard fails, then all of the
data on that shard becomes unavailable.


File: manual.info,  Node: ha-zfs-replication,  Next: ha-memcached,  Prev: ha-vm,  Up: ha-overview

15.5 Using ZFS Replication
==========================

* Menu:

* ha-zfs-config::                Using ZFS for File System Replication
* ha-zfs-mysql::                 Configuring MySQL for ZFS Replication
* ha-zfs-mysql-recovery::        Handling MySQL Recovery with ZFS

To support high availability environments, providing an instant copy of
the information on both the currently active machine and the hot backup
is a critical part of the HA solution. There are many solutions to this
problem, including *Note replication:: and *Note ha-drbd::.

The ZFS file system provides functionality to create a snapshot of the
file system contents, transfer the snapshot to another machine, and
extract the snapshot to recreate the file system. You can create a
snapshot at any time, and you can create as many snapshots as you like.
By continually creating, transferring and restoring snapshots, you can
provide synchronization between one or more machines in a fashion
similar to DRBD.

To understand the replication solution within ZFS, you must first
understand the ZFS environment. Below is a simple Solaris system
running with a single ZFS pool, mounted at `/scratchpool':

     Filesystem             size   used  avail capacity  Mounted on
     /dev/dsk/c0d0s0        4.6G   3.7G   886M    82%    /
     /devices                 0K     0K     0K     0%    /devices
     ctfs                     0K     0K     0K     0%    /system/contract
     proc                     0K     0K     0K     0%    /proc
     mnttab                   0K     0K     0K     0%    /etc/mnttab
     swap                   1.4G   892K   1.4G     1%    /etc/svc/volatile
     objfs                    0K     0K     0K     0%    /system/object
     /usr/lib/libc/libc_hwcap1.so.1
                            4.6G   3.7G   886M    82%    /lib/libc.so.1
     fd                       0K     0K     0K     0%    /dev/fd
     swap                   1.4G    40K   1.4G     1%    /tmp
     swap                   1.4G    28K   1.4G     1%    /var/run
     /dev/dsk/c0d0s7         26G   913M    25G     4%    /export/home
     scratchpool             16G    24K    16G     1%    /scratchpool

The MySQL data is stored in a directory on `/scratchpool'. To help
demonstrate some of the basic replication functionality, there are also
other items stored in `/scratchpool' as well:

     total 17
     drwxr-xr-x  31 root     bin           50 Jul 21 07:32 DTT/
     drwxr-xr-x   4 root     bin            5 Jul 21 07:32 SUNWmlib/
     drwxr-xr-x  14 root     sys           16 Nov  5 09:56 SUNWspro/
     drwxrwxrwx  19 1000     1000          40 Nov  6 19:16 emacs-22.1/

To create a snapshot of the file system, you use `zfs snapshot', and
then specify the pool and the snapshot name:

     root-shell> zfs snapshot scratchpool@snap1

To list the snapshots already taken:

     root-shell> zfs list -t snapshot
     NAME                USED  AVAIL  REFER  MOUNTPOINT
     scratchpool@snap1      0      -  24.5K  -
     scratchpool@snap2      0      -  24.5K  -

The snapshots themselves are stored within the file system metadata,
and the space required to keep them varies as time goes on because of
the way the snapshots are created. The initial creation of a snapshot
is very quick, because instead of taking an entire copy of the data and
metadata required to hold the entire snapshot, ZFS merely records the
point in time and metadata of when the snapshot was created.

As more changes to the original file system are made, the size of the
snapshot increases because more space is required to keep the record of
the old blocks. Furthermore, if you create lots of snapshots, say one
per day, and then delete the snapshots from earlier in the week, the
size of the newer snapshots may also increase, as the changes that make
up the newer state have to be included in the more recent snapshots,
rather than being spread over the seven snapshots that make up the week.

The only issue, from a backup perspective, is that snapshots exist
within the confines of the original file system. To get the snapshot
into a format that you can copy to another file system, tape, and so
on, you use the `zfs send' command to create a stream version of the
snapshot.

For example, to write the snapshot out to a file:

     root-shell> zfs send scratchpool@snap1 >/backup/scratchpool-snap1

Or tape:

     root-shell> zfs send scratchpool@snap1 >/dev/rmt/0

You can also write out the incremental changes between two snapshots
using `zfs send':

     root-shell> zfs send scratchpool@snap1 scratchpool@snap2 >/backup/scratchpool-changes

To recover a snapshot, you use `zfs recv', which applies the snapshot
information either to a new file system, or to an existing one.


File: manual.info,  Node: ha-zfs-config,  Next: ha-zfs-mysql,  Prev: ha-zfs-replication,  Up: ha-zfs-replication

15.5.1 Using ZFS for File System Replication
--------------------------------------------

Because `zfs send' and `zfs recv' use streams to exchange data, you can
use them to replicate information from one system to another by
combining `zfs send', `ssh', and `zfs recv'.

For example, if a snapshot of the `scratchpool' file system has been
created and this needs to be copied to a new system or file system
called `slavepool'. You would use the following command, combining the
snapshot of `scratchpool', the transmission to the slave machine (using
`ssh'), and the recovery of the snapshot on the slave using `zfs recv':

     root-shell> zfs send scratchpool@snap1 |ssh mc@slave pfexec zfs recv -F slavepool

The first part, `zfs send scratchpool@snap1', streams the snapshot, the
second, `ssh mc@slave', and the third, `pfexec zfs recv -F slavepool',
receives the streamed snapshot data and writes it to slavepool. In this
instance, I've specified the `-F' option which forces the snapshot data
to be applied, and is therefore destructive. This is fine, as I'm
creating the first version of my replicated file system.

On the slave machine, the replicated file system contains the exact
same content:

     root-shell> ls -al /slavepool/
     total 23
     drwxr-xr-x   6 root     root           7 Nov  8 09:13 ./
     drwxr-xr-x  29 root     root          34 Nov  9 07:06 ../
     drwxr-xr-x  31 root     bin           50 Jul 21 07:32 DTT/
     drwxr-xr-x   4 root     bin            5 Jul 21 07:32 SUNWmlib/
     drwxr-xr-x  14 root     sys           16 Nov  5 09:56 SUNWspro/
     drwxrwxrwx  19 1000     1000          40 Nov  6 19:16 emacs-22.1/

Once a snapshot has been created, to synchronize the file system again,
you create a new snapshot and then use the incremental snapshot feature
of `zfs send' to send the changes between the two snapshots to the
slave machine again:

     root-shell> zfs send -i scratchpool@snapshot1 scratchpool@snapshot2 |ssh mc@192.168.0.93 pfexec zfs recv slavepool

Without further modification, this operation fails, because the file
system on the slave machine can currently be modified, and you can't
apply the incremental changes to a destination file system that has
changed. It is the metadata that has changed. The metadata about the
file system, like the last time it was accessed - in this case, it is
our `ls' that caused the problem.

To prevent changes on the slave file system, you must set the file
system on the slave to be read-only:

     root-shell> zfs set readonly=on slavepool

Setting `readonly' means that you cannot change the file system on the
slave by normal means, including the file system metadata. Operations
that would normally update metadata (like our `ls') silently perform
their function without attempting to update the file system state.

In essence, the slave file system is nothing but a static copy of the
original file system. However, even when configured to to be read-only,
a file system can have snapshots applied to it. Now the file system is
read only, re-run the initial copy:

     root-shell> zfs send scratchpool@snap1 |ssh mc@slave pfexec zfs recv -F slavepool

Now you can make changes to the original file system and replicate them
to the slave.


File: manual.info,  Node: ha-zfs-mysql,  Next: ha-zfs-mysql-recovery,  Prev: ha-zfs-config,  Up: ha-zfs-replication

15.5.2 Configuring MySQL for ZFS Replication
--------------------------------------------

Configuring MySQL on the source file system is a case of creating the
data on the file system that you intend to replicate. The configuration
file in the example below has been updated to use
`/scratchpool/mysql-data' as the data directory, and now you can
initialize the tables:

     root-shell> mysql_install_db --defaults-file=/etc/mysql/5.0/my.cnf --user=mysql

To synchronize the initial information, perform a new snapshot and then
send an incremental snapshot to the slave using `zfs send':

     root-shell> zfs snapshot scratchpool@snap2
     root-shell> zfs send -i scratchpool@snap1 scratchpool@snap2|ssh mc@192.168.0.93 pfexec zfs recv slavepool

Doublecheck that the slave has the data by looking at the MySQL data
directory on the `slavepool':

     root-shell> ls -al /slavepool/mysql-data/

Now you can start up MySQL, create some data, and then replicate the
changes using `zfs send'/` zfs recv' to the slave to synchronize the
changes.

The rate at which you perform the synchronization depends on your
application and environment. The limitation is the speed required to
perform the snapshot and then to send the changes over the network.

To automate the process, create a script that performs the snapshot,
send, and receive operation, and then use `cron' to synchronize the
changes at set times or intervals. For automated operations, see Tim
Foster's zfs replication tool
(http://blogs.sun.com/timf/entry/zfs_automatic_snapshots_now_with).


File: manual.info,  Node: ha-zfs-mysql-recovery,  Prev: ha-zfs-mysql,  Up: ha-zfs-replication

15.5.3 Handling MySQL Recovery with ZFS
---------------------------------------

When using ZFS replication to provide a constant copy of your data,
ensure that you can recover your tables, either manually or
automatically, in the event of a failure of the original system.

In the event of a failure, follow this sequence:

  1. Stop the script on the master, if it is still up and running.

  2. Set the slave file system to be read/write:

          root-shell> zfs set readonly=off slavepool

  3. Start up *Note `mysqld': mysqld. on the slave. If you are using
     `InnoDB', `Falcon' or `Maria' you get auto-recovery, if it is
     needed, to make sure the table data is correct, as shown here when
     I started up from our mid-INSERT snapshot:

          InnoDB: The log sequence number in ibdata files does not match
          InnoDB: the log sequence number in the ib_logfiles!
          081109 15:59:59  InnoDB: Database was not shut down normally!
          InnoDB: Starting crash recovery.
          InnoDB: Reading tablespace information from the .ibd files...
          InnoDB: Restoring possible half-written data pages from the doublewrite
          InnoDB: buffer...
          081109 16:00:03  InnoDB: Started; log sequence number 0 1142807951
          081109 16:00:03 [Note] /slavepool/mysql-5.0.67-solaris10-i386/bin/mysqld: ready for connections.
          Version: '5.0.67'  socket: '/tmp/mysql.sock'  port: 3306  MySQL Community Server (GPL)

On MyISAM tables, you might need to run `REPAIR TABLE', and you might
even have lost some information.  Use *Note `InnoDB':
innodb-storage-engine. tables and a regular synchronization schedule to
reduce the risk for significant data loss.


File: manual.info,  Node: ha-memcached,  Next: mysql-proxy,  Prev: ha-zfs-replication,  Up: ha-overview

15.6 Using MySQL with `memcached'
=================================

* Menu:

* ha-memcached-install::         Installing `memcached'
* ha-memcached-using::           Using `memcached'
* ha-memcached-interfaces::      `memcached' Interfaces
* ha-memcached-stats::           Getting `memcached' Statistics
* ha-memcached-faq::             `memcached' FAQ

The largest problem with scalability within a typical environment is
the speed with which you can access information. For frequently
accessed information, using MySQL can be slow because each access of
information requires execution of the SQL query and recovery of the
information from the database. This also means that queries on tables
that are locked or blocking may delay your query and reduce the speed
of recovery of information.

`memcached' is a simple, yet highly scalable key-based cache that
stores data and objects wherever dedicated or spare RAM is available
for very quick access by applications. To use, you run `memcached' on
one or more hosts and then use the shared cache to store objects.
Because each host's RAM is storing information, the access speed is
much faster than loading the information from disk. This can provide a
significant performance boost in retrieving data versus loading the data
natively from a database. Also, because the cache is just a repository
for information, you can use the cache to store any data, including
complex structures that would normally require a significant amount of
effort to create, but in a ready-to-use format, helping to reduce the
load on your MySQL servers.

The typical usage environment is to modify your application so that
information is read from the cache provided by `memcached'. If the
information isn't in `memcached', then the data is loaded from the MySQL
database and written into the cache so that future requests for the
same object benefit from the cached data.

For a typical deployment layout, see *Note ha-memcached-fig-overview::.

FIGURE GOES HERE: `memcached' Architecture Overview

In the example structure, any of the clients can contact one of the
`memcached' servers to request a given key. Each client is configured
to talk to all of the servers shown in the illustration. Within the
client, when the request is made to store the information, the key used
to reference the data is hashed and this hash is then used to select
one of the `memcached' servers. The selection of the `memcached' server
takes place on the client before the server is contacted, keeping the
process lightweight.

The same algorithm is used again when a client requests the same key.
The same key generates the same hash, and the same `memcached' server
is selected as the source for the data. Using this method, the cached
data is spread among all of the `memcached' servers, and the cached
information is accessible from any client. The result is a distributed,
memory-based, cache that can return information, particularly complex
data and structures, much faster than natively reading the information
from the database.

The data held within a `memcached' server is never stored on disk (only
in RAM, which means there is no persistence of data), and the RAM cache
is always populated from the backing store (a MySQL database). If a
`memcached' server fails, the data can always be recovered from the
MySQL database, albeit at a slower speed than loading the information
from the cache.

In April 2011, MySQL announced the preview of a new memcached interface
for the InnoDB and MySQL Cluster storage engines.

Using the memcached API, web services can directly access the InnoDB
and MySQL Cluster storage engines without transformations to SQL,
ensuring low latency and high throughput for read/write queries.
Operations such as SQL parsing are eliminated and more of the server's
hardware resources (CPU, memory and I/O) are dedicated to servicing the
query within the storage engine itself.

These are targeted to be incorporated into future MySQL 5.6 Milestone
and MySQL Cluster Development Releases.

You can learn more about these interfaces from this Dev Zone article:
`http://dev.mysql.com/tech-resources/articles/nosql-to-mysql-with-memcached.html'.


File: manual.info,  Node: ha-memcached-install,  Next: ha-memcached-using,  Prev: ha-memcached,  Up: ha-memcached

15.6.1 Installing `memcached'
-----------------------------

You can build and install `memcached' from the source code directly, or
you can use an existing operating system package or installation.

*Installing `memcached' from a Binary Distribution*

To install `memcached' on a Red Hat, or Fedora host, use `yum':

     root-shell> yum install memcached

*Note*:

On CentOS, you may be able to obtain a suitable RPM from another
source, or use the source tarball.

To install `memcached' on a Debian or Ubuntu host, use `apt-get':

     root-shell> apt-get install memcached

To install `memcached' on a Gentoo host, use `emerge':

     root-shell> emerge install memcached

*Building `memcached' from Source*

On other Unix-based platforms, including Solaris, AIX, HP-UX and Mac OS
X, and Linux distributions not mentioned already, you must install from
source. For Linux, make sure you have a 2.6-based kernel, which
includes the improved `epoll' interface. For all platforms, ensure that
you have `libevent' 1.1 or higher installed. You can obtain `libevent'
from `libevent' web page (http://www.monkey.org/~provos/libevent/).

You can obtain the source for `memcached' from `memcached' Web site
(http://www.danga.com/memcached).

To build `memcached', follow these steps:

  1. Extract the `memcached' source package:

          shell> gunzip -c memcached-1.2.5.tar.gz | tar xf -

  2. Change to the `memcached-1.2.5 directory:'

          shell> cd memcached-1.2.5

  3. Run `configure'

          shell> ./configure

     Some additional options you might specify to the `configure':

        * `--prefix'

          To specify a different installation directory, use the
          `--prefix' option:

               shell> ./configure --prefix=/opt

          The default is to use the `/usr/local' directory.

        * `--with-libevent'

          If you have installed `libevent' and `configure' cannot find
          the library, use the `--with-libevent' option to specify the
          location of the installed library.

        * `--enable-64bit'

          To build a 64-bit version of `memcached' (which enables you
          to use a single instance with a large RAM allocation), use
          `--enable-64bit'.

        * `--enable-threads'

          To enable multi-threading support in `memcached', which
          improves the response times on servers with a heavy load, use
          `--enable-threads'. You must have support for the POSIX
          threads within your operating system to enable thread
          support. For more information on the threading support, see
          *Note ha-memcached-using-threads::.

        * `--enable-dtrace'

          `memcached' includes a range of DTrace threads that can be
          used to monitor and benchmark a `memcached' instance. For more
          information, see *Note ha-memcached-using-dtrace::.

  4. Run `make' to build `memcached':

          shell> make

  5. Run `make install' to install `memcached':

          shell> make install


File: manual.info,  Node: ha-memcached-using,  Next: ha-memcached-interfaces,  Prev: ha-memcached-install,  Up: ha-memcached

15.6.2 Using `memcached'
------------------------

* Menu:

* ha-memcached-using-deployment::  `memcached' Deployment
* ha-memcached-using-namespaces::  Using namespaces
* ha-memcached-using-expiry::    Data Expiry
* ha-memcached-using-hashtypes::  `memcached' Hashing/Distribution Types
* ha-memcached-using-dtrace::    Using `memcached' and DTrace
* ha-memcached-using-memory::    Memory allocation within `memcached'
* ha-memcached-using-threads::   `memcached' thread Support
* ha-memcached-using-logs::      `memcached' Logs

To start using `memcached', you must start the `memcached' service on
one or more servers.  Running `memcached' sets up the server, allocates
the memory and starts listening for connections from clients.

*Note*:

You do not need to be a privileged user (`root') to run `memcached'
except to listen on one of the privileged TCP/IP ports (below 1024).
You must, however, use a user that has not had their memory limits
restricted using `setrlimit' or similar.

To start the server, run `memcached' as a nonprivileged (that is,
non-`root') user:

     shell> memcached

By default, `memcached' uses the following settings:

   * Memory allocation of 64MB

   * Listens for connections on all network interfaces, using port 11211

   * Supports a maximum of 1024 simultaneous connections

Typically, you would specify the full combination of options that you
want when starting `memcached', and normally provide a startup script
to handle the initialization of `memcached'. For example, the following
line starts `memcached' with a maximum of 1024MB RAM for the cache,
listening on port 11211 on the IP address 192.168.0.110, running has a
background daemon:

     shell> memcached -d -m 1024 -p 11211 -l 192.168.0.110

To ensure that `memcached' is started up on boot, check the init script
and configuration parameters.

`memcached' supports the following options:

   * `-u user'

     If you start `memcached' as `root', use the `-u' option to specify
     the user for executing `memcached':

          shell> memcached -u memcache

   * `-m memory'

     Set the amount of memory allocated to `memcached' for object
     storage. Default is 64MB.

     To increase the amount of memory allocated for the cache, use the
     `-m' option to specify the amount of RAM to be allocated (in
     megabytes). The more RAM you allocate, the more data you can store
     and therefore the more effective your cache is.

     *Warning*:

     Do not specify a memory allocation larger than your available RAM.
     If you specify too large a value, then some RAM allocated for
     `memcached' uses swap space, and not physical RAM. This may lead
     to delays when storing and retrieving values, because data is
     swapped to disk, instead of storing the data directly in RAM.

     You can use the output of the `vmstat' command to get the free
     memory, as shown in `free' column:

          shell> vmstat
          kthr      memory            page            disk          faults      cpu
          r b w   swap  free  re  mf pi po fr de sr s1 s2 -- --   in   sy   cs us sy id
          0 0 0 5170504 3450392 2  7  2  0  0  0  4  0  0  0  0  296   54  199  0  0 100

     For example, to allocate 3GB of RAM:

          shell> memcached -m 3072

     On 32-bit x86 systems where you are using PAE to access memory
     above the 4GB limit, you cannot allocate RAM beyond the maximum
     process size. You can get around this by running multiple
     instances of `memcached', each listening on a different port:

          shell> memcached -m 1024 -p11211
          shell> memcached -m 1024 -p11212
          shell> memcached -m 1024 -p11213

     *Note*:

     On all systems, particularly 32-bit, ensure that you leave enough
     room for both `memcached' application in addition to the memory
     setting. For example, if you have a dedicated `memcached' host
     with 4GB of RAM, do not set the memory size above 3500MB.  Failure
     to do this may cause either a crash or severe performance issues.

   * `-l interface'

     Specify a network interface/address to listen for connections.
     The default is to listen on all available address (`INADDR_ANY').

          shell> memcached -l 192.168.0.110

     Support for IPv6 address support was added in `memcached' 1.2.5.

   * `-p port'

     Specify the TCP port to use for connections. Default is 18080.

          shell> memcached -p 18080

   * `-U port'

     Specify the UDP port to use for connections. Default is 11211, 0
     switches UDP off.

          shell> memcached -U 18080

   * `-s socket'

     Specify a Unix socket to listen on.

     If you are running `memcached' on the same server as the clients,
     you can disable the network interface and use a local UNIX socket
     using the `-s' option:

          shell> memcached -s /tmp/memcached

     Using a UNIX socket automatically disables network support, and
     saves network ports (allowing more ports to be used by your web
     server or other process).

   * `-a mask'

     Specify the access mask to be used for the Unix socket, in octal.
     Default is 0700.

   * `-c connections'

     Specify the maximum number of simultaneous connections to the
     `memcached' service. The default is 1024.

          shell> memcached -c 2048

     Use this option, either to reduce the number of connections (to
     prevent overloading `memcached' service) or to increase the number
     to make more effective use of the server running `memcached'
     server.

   * `-t threads'

     Specify the number of threads to use when processing incoming
     requests.

     By default, `memcached' is configured to use 4 concurrent threads.
     The threading improves the performance of storing and retrieving
     data in the cache, using a locking system to prevent different
     threads overwriting or updating the same values. To increase or
     decrease the number of threads, use the `-t' option:

          shell> memcached -t 8

   * `-d'

     Run `memcached' as a daemon (background) process:

          shell> memcached -d

   * `-r'

     Maximize the size of the core file limit. In the event of a
     failure, this attempts to dump the entire memory space to disk as
     a core file, up to any limits imposed by `setrlimit'.

   * `-M'

     Return an error to the client when the memory has been exhausted.
     This replaces the normal behavior of removing older items from the
     cache to make way for new items.

   * `-k'

     Lock down all paged memory. This reserves the memory before use,
     instead of allocating new slabs of memory as new items are stored
     in the cache.

     *Note*:

     There is a user-level limit on how much memory you can lock.
     Trying to allocate more than the available memory fails. You can
     set the limit for the user you started the daemon with (not for
     the `-u user' user) within the shell by using `ulimit -S -l NUM_KB'

   * `-v'

     Verbose mode. Prints errors and warnings while executing the main
     event loop.

   * `-vv'

     Very verbose mode. In addition to information printed by `-v',
     also prints each client command and the response.

   * `-vvv'

     Extremely verbose mode. In addition to information printed by
     `-vv', also show the internal state transitions.

   * `-h'

     Print the help message and exit.

   * `-i'

     Print the `memcached' and `libevent' license.

   * `-I mem'

     Specify the maximum size permitted for storing an object within
     the `memcached' instance. The size supports a unit postfix (`k'
     for kilobytes, `m' for megabytes). For example, to increase the
     maximum supported object size to 32MB:

          shell> memcached -I 32m

     The maximum object size you can specify is 128MB, the default
     remains at 1MB.

     This option was added in 1.4.2.

   * `-b'

     Set the backlog queue limit. The backlog queue configures how many
     network connections can be waiting to be processed by `memcached'.
     Increasing this limit may reduce errors received by the client
     that it is not able to connect to the `memcached' instance, but
     does not improve the performance of the server. The default is
     1024.

   * `-P pidfile'

     Save the process ID of the `memcached' instance into `file'.

   * `-f'

     Set the chunk size growth factor. When allocating new memory
     chunks, the allocated size of new chunks is determined by
     multiplying the default slab size by this factor.

     To see the effects of this option without extensive testing, use
     the `-vv' command-line option to show the calculated slab sizes.
     For more information, see *Note ha-memcached-using-logs::.

   * `-n bytes'

     The minimum space allocated for the key+value+flags information.
     The default is 48 bytes.

   * `-L'

     On systems that support large memory pages, enables large memory
     page use. Using large memory pages enables `memcached' to allocate
     the item cache in one large chunk, which can improve the
     performance by reducing the number misses when accessing memory.

   * `-C'

     Disable the use of compare and swap (CAS) operations.

     This option was added in `memcached' 1.3.x.

   * `-D char'

     Set the default character to be used as a delimiter between the
     key prefixes and IDs. This is used for the per-prefix statistics
     reporting (see *Note ha-memcached-stats::). The default is the
     colon (`:'). If this option is used, statistics collection is
     turned on automatically. If not used, you can enable stats
     collection by sending the `stats detail on' command to the server.

     This option was added in `memcached' 1.3.x.

   * `-R num'

     Sets the maximum number of requests per event process. The default
     is 20.

   * `-B protocol'

     Set the binding protocol, that is, the default `memcached'
     protocol support for client connections. Options are `ascii',
     `binary' or `auto'.  Automatic (`auto') is the default.

     This option was added in `memcached' 1.4.0.


File: manual.info,  Node: ha-memcached-using-deployment,  Next: ha-memcached-using-namespaces,  Prev: ha-memcached-using,  Up: ha-memcached-using

15.6.2.1 `memcached' Deployment
...............................

When using `memcached' you can use a number of different potential
deployment strategies and topologies. The exact strategy to use depends
on your application and environment. When developing a system for
deploying `memcached' within your system, keep in mind the following
points:

   * `memcached' is only a caching mechanism. It shouldn't be used to
     store information that you cannot otherwise afford to lose and
     then load from a different location.

   * There is no security built into the `memcached' protocol. At a
     minimum, make sure that the servers running `memcached' are only
     accessible from inside your network, and that the network ports
     being used are blocked (using a firewall or similar). If the
     information on the `memcached' servers that is being stored is any
     sensitive, then encrypt the information before storing it in
     `memcached'.

   * `memcached' does not provide any sort of failover. Because there
     is no communication between different `memcached' instances. If an
     instance fails, your application must capable of removing it from
     the list, reloading the data and then writing data to another
     `memcached' instance.

   * Latency between the clients and the `memcached' can be a problem
     if you are using different physical machines for these tasks. If
     you find that the latency is a problem, move the `memcached'
     instances to be on the clients.

   * Key length is determined by the `memcached' server. The default
     maximum key size is 250 bytes.

   * Using a single `memcached' instance, especially for multiple
     clients, is generally a bad idea as it introduces a single point
     of failure. Instead provide at least two `memcached' instances so
     that a failure can be handled appropriately. If possible, you
     should create as many `memcached' nodes as possible. When adding
     and removing `memcached' instances from a pool, the hashing and
     distribution of key/value pairs may be affected.  For information
     on how to avoid problems, see *Note ha-memcached-using-hashtypes::.


File: manual.info,  Node: ha-memcached-using-namespaces,  Next: ha-memcached-using-expiry,  Prev: ha-memcached-using-deployment,  Up: ha-memcached-using

15.6.2.2 Using namespaces
.........................

The `memcached' cache is a very simple massive key/value storage
system, and as such there is no way of compartmentalizing data
automatically into different sections.  For example, if you are storing
information by the unique ID returned from a MySQL database, then
storing the data from two different tables could run into issues
because the same ID might be valid in both tables.

Some interfaces provide an automated mechanism for creating
_namespaces_ when storing information into the cache. In practice,
these namespaces are merely a prefix before a given ID that is applied
every time a value is stored or retrieve from the cache.

You can implement the same basic principle by using keys that describe
the object and the unique identifier within the key that you supply
when the object is stored. For example, when storing user data, prefix
the ID of the user with `user:' or `user-'.

*Note*:

Using namespaces or prefixes only controls the keys stored/retrieved.
There is no security within `memcached', and therefore no way to enforce
that a particular client only accesses keys with a particular
namespace. Namespaces are only useful as a method of identifying data
and preventing corruption of key/value pairs.


File: manual.info,  Node: ha-memcached-using-expiry,  Next: ha-memcached-using-hashtypes,  Prev: ha-memcached-using-namespaces,  Up: ha-memcached-using

15.6.2.3 Data Expiry
....................

There are two types of data expiry within a `memcached' instance. The
first type is applied at the point when you store a new key/value pair
into the `memcached' instance. If there is not enough space within a
suitable slab to store the value, then an existing least recently used
(LRU) object is removed (evicted) from the cache to make room for the
new item.

The LRU algorithm ensures that the object that is removed is one that
is either no longer in active use or that was used so long ago that its
data is potentially out of date or of little value.  However, in a
system where the memory allocated to `memcached' is smaller than the
number of regularly used objects required in the cache, a lot of expired
items could be removed from the cache even though they are in active
use. You use the statistics mechanism to get a better idea of the level
of evictions (expired objects). For more information, see *Note
ha-memcached-stats::.

You can change this eviction behavior by setting the `-M' command-line
option when starting `memcached'. This option forces an error to be
returned when the memory has been exhausted, instead of automatically
evicting older data.

The second type of expiry system is an explicit mechanism that you can
set when a key/value pair is inserted into the cache, or when deleting
an item from the cache. Using an expiration time can be a useful way of
ensuring that the data in the cache is up to date and in line with your
application needs and requirements.

A typical scenario for explicitly setting the expiry time might include
caching session data for a user when accessing a Web site. `memcached'
uses a lazy expiry mechanism where the explicit expiry time that has
been set is compared with the current time when the object is
requested. Only objects that have not expired are returned.

You can also set the expiry time when explicitly deleting an object
from the cache. In this case, the expiry time is really a timeout and
indicates the period when any attempts to set the value for a given key
are rejected.


File: manual.info,  Node: ha-memcached-using-hashtypes,  Next: ha-memcached-using-dtrace,  Prev: ha-memcached-using-expiry,  Up: ha-memcached-using

15.6.2.4 `memcached' Hashing/Distribution Types
...............................................

The `memcached' client interface supports a number of different
distribution algorithms that are used in multi-server configurations to
determine which host should be used when setting or getting data from a
given `memcached' instance. When you get or set a value, a hash is
constructed from the supplied key and then used to select a host from
the list of configured servers. Because the hashing mechanism uses the
supplied key as the basis for the hash, the same server is selected
during both set and get operations.

You can think of this process as follows. Given an array of servers (a,
b, and c), the client uses a hashing algorithm that returns an integer
based on the key being stored or retrieved.  The resulting value is
then used to select a server from the list of servers configured in the
client. Most standard client hashing within `memcache' clients uses a
simple modulus calculation on the value against the number of
configured `memcached' servers. You can summarize the process in
pseudocode as:

     @memcservers = ['a.memc','b.memc','c.memc'];
     $value = hash($key);
     $chosen = $value % length(@memcservers);

Replacing the above with values:

     @memcservers = ['a.memc','b.memc','c.memc'];
     $value = hash('myid');
     $chosen = 7009 % 3;

In the above example, the client hashing algorithm chooses the server
at index 1 (`7009 % 3 = 1'), and store or retrieve the key and value
with that server.

*Note*:

This selection and hashing process is handled automatically by the
`memcached' client you are using; you need only provide the list of
`memcached' servers to use.

You can see a graphical representation of this below in *Note
ha-memcached-using-hashtypes-fig-selection::.

FIGURE GOES HERE: `memcached' Hash Selection

The same hashing and selection process takes place during any operation
on the specified key within the `memcached' client.

Using this method provides a number of advantages:

   * The hashing and selection of the server to contact is handled
     entirely within the client. This eliminates the need to perform
     network communication to determine the right machine to contact.

   * Because the determination of the `memcached' server occurs
     entirely within the client, the server can be selected
     automatically regardless of the operation being executed (set, get,
     increment, etc.).

   * Because the determination is handled within the client, the
     hashing algorithm returns the same value for a given key; values
     are not affected or reset by differences in the server environment.

   * Selection is very fast. The hashing algorithm on the key value is
     quick and the resulting selection of the server is from a simple
     array of available machines.

   * Using client-side hashing simplifies the distribution of data over
     each `memcached' server. Natural distribution of the values
     returned by the hashing algorithm means that keys are
     automatically spread over the available servers.

Providing that the list of servers configured within the client remains
the same, the same stored key returns the same value, and therefore
selects the same server.

However, if you do not use the same hashing mechanism then the same
data may be recorded on different servers by different interfaces, both
wasting space on your `memcached' and leading to potential differences
in the information.

*Note*:

One way to use a multi-interface compatible hashing mechanism is to use
the `libmemcached' library and the associated interfaces. Because the
interfaces for the different languages (including C, Ruby, Perl and
Python) use the same client library interface, they always generate the
same hash code from the ID.

The problem with client-side selection of the server is that the list
of the servers (including their sequential order) _must_ remain
consistent on each client using the `memcached' servers, and the
servers must be available. If you try to perform an operation on a key
when:

   * A new `memcached' instance has been added to the list of available
     instances

   * A `memcached' instance has been removed from the list of available
     instances

   * The order of the `memcached' instances has changed

When the hashing algorithm is used on the given key, but with a
different list of servers, the hash calculation may choose a different
server from the list.

If a new `memcached' instance is added into the list of servers, as
`new.memc' is in the example below, then a GET operation using the same
key, `myid', can result in a cache-miss. This is because the same value
is computed from the key, which selects the same index from the array
of servers, but index 2 now points to the new server, not the server
`c.memc' where the data was originally stored. This would result in a
cache miss, even though the key exists within the cache on another
`memcached' instance.

FIGURE GOES HERE: `memcached' Hash Selection with New `memcached'
instance

This means that servers `c.memc' and `new.memc ' both contain the
information for key `myid', but the information stored against the key
in eachs server may be different in each instance. A more significant
problem is a much higher number of cache-misses when retrieving data,
as the addition of a new server changes the distribution of keys, and
this in turn requires rebuilding the cached data on the `memcached'
instances, causing an increase in database reads.

The same effect can occur if you actively manage the list of servers
configured in your clients, adding and removing the configured
`memcached' instances as each instance is identified as being
available. For example, removing a `memcached' instance when the client
notices that the instance can no longer be contacted can cause the
server selection to fail as described here.

To prevent this causing significant problems and invalidating your
cache, you can select the hashing algorithm used to select the server.
There are two common types of hashing algorithm, _consistent_ and
_modula_.

With _consistent_ hashing algorithms, the same key when applied to a
list of servers always uses the same server to store or retrieve the
keys, even if the list of configured servers changes. This means that
you can add and remove servers from the configure list and always use
the same server for a given key. There are two types of consistent
hashing algorithms available, Ketama and Wheel. Both types are
supported by `libmemcached', and implementations are available for PHP
and Java.

Any consistent hashing algorithm has some limitations. When you add
servers to an existing list of configured servers, keys are distributed
to the new servers as part of the normal distribution. When you remove
servers from the list, the keys are re-allocated to another server
within the list, meaning that the cache needs to be re-populated with
the information. Also, a consistent hashing algorithm does not resolve
the issue where you want consistent selection of a server across
multiple clients, but where each client contains a different list of
servers. The consistency is enforced only within a single client.

With a _modula_ hashing algorithm, the client selects a server by first
computing the hash and then choosing a server from the list of
configured servers. As the list of servers changes, so the server
selected when using a modula hashing algorithm also changes. The result
is the behavior described above; changes to the list of servers mean
that different servers are selected when retrieving data, leading to
cache misses and increase in database load as the cache is re-seeded
with information.

If you use only a single `memcached' instance for each client, or your
list of `memcached' servers configured for a client never changes, then
the selection of a hashing algorithm is irrelevant, as it has no
noticeable effect.

If you change your servers regularly, or you use a common set of
servers that are shared among a large number of clients, then using a
consistent hashing algorithm should help to ensure that your cache data
is not duplicated and the data is evenly distributed.


File: manual.info,  Node: ha-memcached-using-dtrace,  Next: ha-memcached-using-memory,  Prev: ha-memcached-using-hashtypes,  Up: ha-memcached-using

15.6.2.5 Using `memcached' and DTrace
.....................................

`memcached' includes a number of different DTrace probes that can be
used to monitor the operation of the server. The probes included can
monitor individual connections, slab allocations, and modifications to
the hash table when a key/value pair is added, updated, or removed.

For more information on DTrace and writing DTrace scripts, read the
DTrace User Guide (http://docs.sun.com/app/docs/doc/819-5488?l=en).

Support for DTrace probes was added to `memcached' 1.2.6 includes a
number of DTrace probes that can be used to help monitor your
application. DTrace is supported on Solaris 10, OpenSolaris, Mac OS X
10.5 and FreeBSD. To enable the DTrace probes in `memcached', build
from source and use the `--enable-dtrace' option. For more information,
see *Note ha-memcached-install::.

The probes supported by `memcached' are:

   * `conn-allocate(connid)'

     Fired when a connection object is allocated from the connection
     pool.

        * `connid': The connection ID

   * `conn-release(connid)'

     Fired when a connection object is released back to the connection
     pool.

     Arguments:

        * `connid': The connection ID

   * `conn-create(ptr)'

     Fired when a new connection object is being created (that is,
     there are no free connection objects in the connection pool).

     Arguments:

        * `ptr': A pointer to the connection object

   * `conn-destroy(ptr)'

     Fired when a connection object is being destroyed.

     Arguments:

        * `ptr': A pointer to the connection object

   * `conn-dispatch(connid, threadid)'

     Fired when a connection is dispatched from the main or
     connection-management thread to a worker thread.

     Arguments:

        * `connid': The connection ID

        * `threadid': The thread ID

   * `slabs-allocate(size, slabclass, slabsize, ptr)'

     Allocate memory from the slab allocator

     Arguments:

        * `size': The requested size

        * `slabclass': The allocation is fulfilled in this class

        * `slabsize': The size of each item in this class

        * `ptr': A pointer to allocated memory

   * `slabs-allocate-failed(size, slabclass)'

     Failed to allocate memory (out of memory)

     Arguments:

        * `size': The requested size

        * `slabclass': The class that failed to fulfill the request

   * `slabs-slabclass-allocate(slabclass)'

     Fired when a slab class needs more space

     Arguments:

        * `slabclass': The class that needs more memory

   * `slabs-slabclass-allocate-failed(slabclass)'

     Failed to allocate memory (out of memory)

     Arguments:

        * `slabclass': The class that failed to grab more memory

   * `slabs-free(size, slabclass, ptr)'

     Release memory

     Arguments:

        * `size': The size of the memory

        * `slabclass': The class the memory belongs to

        * `ptr': A pointer to the memory to release

   * `assoc-find(key, depth)'

     Fired when the when we have searched the hash table for a named
     key. These two elements provide an insight in how well the hash
     function operates. Traversals are a sign of a less optimal
     function, wasting cpu capacity.

     Arguments:

        * `key': The key searched for

        * `depth': The depth in the list of hash table

   * `assoc-insert(key, nokeys)'

     Fired when a new item has been inserted.

     Arguments:

        * `key': The key just inserted

        * `nokeys': The total number of keys currently being stored,
          including the key for which insert was called.

   * `assoc-delete(key, nokeys)'

     Fired when a new item has been removed.

     Arguments:

        * `key': The key just deleted

        * `nokeys': The total number of keys currently being stored,
          excluding the key for which delete was called.

   * `item-link(key, size)'

     Fired when an item is being linked in the cache

     Arguments:

        * `key': The items key

        * `size': The size of the data

   * `item-unlink(key, size)'

     Fired when an item is being deleted

     Arguments:

        * `key': The items key

        * `size': The size of the data

   * `item-remove(key, size)'

     Fired when the refcount for an item is reduced

     Arguments:

        * `key': The items key

        * `size': The size of the data

   * `item-update(key, size)'

     Fired when the "last referenced" time is updated

     Arguments:

        * `key': The items key

        * `size': The size of the data

   * `item-replace(oldkey, oldsize, newkey, newsize)'

     Fired when an item is being replaced with another item

     Arguments:

        * `oldkey': The key of the item to replace

        * `oldsize': The size of the old item

        * `newkey': The key of the new item

        * `newsize': The size of the new item

   * `process-command-start(connid, request, size)'

     Fired when the processing of a command starts

     Arguments:

        * `connid': The connection ID

        * `request': The incoming request

        * `size': The size of the request

   * `process-command-end(connid, response, size)'

     Fired when the processing of a command is done

     Arguments:

        * `connid': The connection ID

        * `response': The response to send back to the client

        * `size': The size of the response

   * `command-get(connid, key, size)'

     Fired for a get-command

     Arguments:

        * `connid': The connection ID

        * `key': The requested key

        * `size': The size of the key's data (or -1 if not found)

   * `command-gets(connid, key, size, casid)'

     Fired for a gets command

     Arguments:

        * `connid': The connection ID

        * `key': The requested key

        * `size': The size of the key's data (or -1 if not found)

        * `casid': The casid for the item

   * `command-add(connid, key, size)'

     Fired for a add-command

     Arguments:

        * `connid': The connection ID

        * `key': The requested key

        * `size': The new size of the key's data (or -1 if not found)

   * `command-set(connid, key, size)'

     Fired for a set-command

     Arguments:

        * `connid': The connection ID

        * `key': The requested key

        * `size': The new size of the key's data (or -1 if not found)

   * `command-replace(connid, key, size)'

     Fired for a replace-command

     Arguments:

        * `connid': The connection ID

        * `key': The requested key

        * `size': The new size of the key's data (or -1 if not found)

   * `command-prepend(connid, key, size)'

     Fired for a prepend-command

     Arguments:

        * `connid': The connection ID

        * `key': The requested key

        * `size': The new size of the key's data (or -1 if not found)

   * `command-append(connid, key, size)'

     Fired for a append-command

     Arguments:

        * `connid': The connection ID

        * `key': The requested key

        * `size': The new size of the key's data (or -1 if not found)

   * `command-cas(connid, key, size, casid)'

     Fired for a cas-command

     Arguments:

        * `connid': The connection ID

        * `key': The requested key

        * `size': The size of the key's data (or -1 if not found)

        * `casid': The cas ID requested

   * `command-incr(connid, key, val)'

     Fired for incr command

     Arguments:

        * `connid': The connection ID

        * `key': The requested key

        * `val': The new value

   * `command-decr(connid, key, val)'

     Fired for decr command

     Arguments:

        * `connid': The connection ID

        * `key': The requested key

        * `val': The new value

   * `command-delete(connid, key, exptime)'

     Fired for a delete command

     Arguments:

        * `connid': The connection ID

        * `key': The requested key

        * `exptime': The expiry time


File: manual.info,  Node: ha-memcached-using-memory,  Next: ha-memcached-using-threads,  Prev: ha-memcached-using-dtrace,  Up: ha-memcached-using

15.6.2.6 Memory allocation within `memcached'
.............................................

When you first start `memcached', the memory that you have configured
is not automatically allocated.  Instead, `memcached' only starts
allocating and reserving physical memory once you start saving
information into the cache.

When you start to store data into the cache, `memcached' does not
allocate the memory for the data on an item by item basis. Instead, a
slab allocation is used to optimize memory usage and prevent memory
fragmentation when information expires from the cache.

With slab allocation, memory is reserved in blocks of 1MB. The slab is
divided up into a number of blocks of equal size. When you try to store
a value into the cache, `memcached' checks the size of the value that
you are adding to the cache and determines which slab contains the
right size allocation for the item. If a slab with the item size
already exists, the item is written to the block within the slab.

If the new item is bigger than the size of any existing blocks, then a
new slab is created, divided up into blocks of a suitable size. If an
existing slab with the right block size already exists, but there are
no free blocks, a new slab is created. If you update an existing item
with data that is larger than the existing block allocation for that
key, then the key is re-allocated into a suitable slab.

For example, the default size for the smallest block is 88 bytes (40
bytes of value, and the default 48 bytes for the key and flag data). If
the size of the first item you store into the cache is less than 40
bytes, then a slab with a block size of 88 bytes is created and the
value stored.

If the size of the data that you intend to store is larger than this
value, then the block size is increased by the chunk size factor until
a block size large enough to hold the value is determined. The block
size is always a function of the scale factor, rounded up to a block
size which is exactly divisible into the chunk size.

For a sample of the structure, see *Note ha-memcached-fig-slabs::.

FIGURE GOES HERE: Memory Allocation in `memcached'

The result is that you have multiple pages allocated within the range
of memory allocated to `memcached'. Each page is 1MB in size (by
default), and is split into a different number of chunks, according to
the chunk size required to store the key/value pairs. Each instance has
multiple pages allocated, and a page is always created when a new item
needs to be created requiring a chunk of a particular size. A slab may
consist of multiple pages, and each page within a slab contains an equal
number of chunks.

The chunk size of a new slab is determined by the base chunk size
combined with the chunk size growth factor. For example, if the initial
chunks are 104 bytes in size, and the default chunk size growth factor
is used (1.25), then the next chunk size allocated would be the best
power of 2 fit for 104*1.25, or 136 bytes.

Allocating the pages in this way ensures that memory does not get
fragmented. However, depending on the distribution of the objects that
you store, it may lead to an inefficient distribution of the slabs and
chunks if you have significantly different sized items. For example,
having a relatively small number of items within each chunk size may
waste a lot of memory with just few chunks in each allocated page.

You can tune the growth factor to reduce this effect by using the `-f'
command line option, which adapts the growth factor applied to make
more effective use of the chunks and slabs allocated. For information
on how to determine the current slab allocation statistics, see *Note
ha-memcached-stats-slabs::.

If your operating system supports it, you can also start `memcached'
with the `-L' command line option. This option preallocates all the
memory during startup using large memory pages. This can improve
performance by reducing the number of misses in the CPU memory cache.


File: manual.info,  Node: ha-memcached-using-threads,  Next: ha-memcached-using-logs,  Prev: ha-memcached-using-memory,  Up: ha-memcached-using

15.6.2.7 `memcached' thread Support
...................................

If you enable the thread implementation within when building
`memcached' from source, then `memcached' uses multiple threads in
addition to the `libevent' system to handle requests.

When enabled, the threading implementation operates as follows:

   * Threading is handled by wrapping functions within the code to
     provide basic protection from updating the same global structures
     at the same time.

   * Each thread uses its own instance of the `libevent' to help
     improve performance.

   * TCP/IP connections are handled with a single thread listening on
     the TCP/IP socket. Each connection is then distribution to one of
     the active threads on a simple round-robin basis. Each connection
     then operates solely within this thread while the connection
     remains open.

   * For UDP connections, all the threads listen to a single UDP socket
     for incoming requests. Threads that are not currently dealing with
     another request ignore the incoming packet. One of the remaining,
     nonbusy, threads reads the request and sends the response. This
     implementation can lead to increased CPU load as threads wake from
     sleep to potentially process the request.

Using threads can increase the performance on servers that have
multiple CPU cores available, as the requests to update the hash table
can be spread between the individual threads. To minimize overhead from
the locking mechanism employed, experiment with different thread values
to achieve the best performance based on the number and type of
requests within your given workload.


File: manual.info,  Node: ha-memcached-using-logs,  Prev: ha-memcached-using-threads,  Up: ha-memcached-using

15.6.2.8 `memcached' Logs
.........................

If you enable verbose mode, using the `-v', `-vv', or `-vvv' options,
then the information output by `memcached' includes details of the
operations being performed.

Without the verbose options, `memcached' normally produces no output
during normal operating.

   * *Output when using `-v'*

     The lowest verbosity level shows you:

        * Errors and warnings

        * Transient errors

        * Protocol and socket errors, including exhausting available
          connections

        * Each registered client connection, including the socket
          descriptor number and the protocol used.

          For example:

               32: Client using the ascii protocol
               33: Client using the ascii protocol

          Note that the socket descriptor is only valid while the
          client remains connected. Non-persistant connections may not
          be effectively represented.

     Examples of the error messages output at this level include:

          <%d send buffer was %d, now %d
          Can't listen for events on fd %d
          Can't read from libevent pipe
          Catastrophic: event fd doesn't match conn fd!
          Couldn't build response
          Couldn't realloc input buffer
          Couldn't update event
          Failed to build UDP headers
          Failed to read, and not due to blocking
          Too many open connections
          Unexpected state %d

   * *Output when using `-vv'*

     When using the second level of verbosity, you get more detailed
     information about protocol operations, keys updated, chunk and
     network operatings and details.

     During the initial start-up of `memcached' with this level of
     verbosity, you are shown the sizes of the individual slab classes,
     the chunk sizes, and the number of entries per slab. These do not
     show the allocation of the slabs, just the slabs that would be
     created when data is added. You are also given information about
     the listen queues and buffers used to send information. A sample
     of the output generated for a TCP/IP based system with the default
     memory and growth factors is given below:

          shell> memcached -vv
          slab class   1: chunk size     80 perslab 13107
          slab class   2: chunk size    104 perslab 10082
          slab class   3: chunk size    136 perslab  7710
          slab class   4: chunk size    176 perslab  5957
          slab class   5: chunk size    224 perslab  4681
          slab class   6: chunk size    280 perslab  3744
          slab class   7: chunk size    352 perslab  2978
          slab class   8: chunk size    440 perslab  2383
          slab class   9: chunk size    552 perslab  1899
          slab class  10: chunk size    696 perslab  1506
          slab class  11: chunk size    872 perslab  1202
          slab class  12: chunk size   1096 perslab   956
          slab class  13: chunk size   1376 perslab   762
          slab class  14: chunk size   1720 perslab   609
          slab class  15: chunk size   2152 perslab   487
          slab class  16: chunk size   2696 perslab   388
          slab class  17: chunk size   3376 perslab   310
          slab class  18: chunk size   4224 perslab   248
          slab class  19: chunk size   5280 perslab   198
          slab class  20: chunk size   6600 perslab   158
          slab class  21: chunk size   8256 perslab   127
          slab class  22: chunk size  10320 perslab   101
          slab class  23: chunk size  12904 perslab    81
          slab class  24: chunk size  16136 perslab    64
          slab class  25: chunk size  20176 perslab    51
          slab class  26: chunk size  25224 perslab    41
          slab class  27: chunk size  31536 perslab    33
          slab class  28: chunk size  39424 perslab    26
          slab class  29: chunk size  49280 perslab    21
          slab class  30: chunk size  61600 perslab    17
          slab class  31: chunk size  77000 perslab    13
          slab class  32: chunk size  96256 perslab    10
          slab class  33: chunk size 120320 perslab     8
          slab class  34: chunk size 150400 perslab     6
          slab class  35: chunk size 188000 perslab     5
          slab class  36: chunk size 235000 perslab     4
          slab class  37: chunk size 293752 perslab     3
          slab class  38: chunk size 367192 perslab     2
          slab class  39: chunk size 458992 perslab     2
          <26 server listening (auto-negotiate)
          <29 server listening (auto-negotiate)
          <30 send buffer was 57344, now 2097152
          <31 send buffer was 57344, now 2097152
          <30 server listening (udp)
          <30 server listening (udp)
          <31 server listening (udp)
          <30 server listening (udp)
          <30 server listening (udp)
          <31 server listening (udp)
          <31 server listening (udp)
          <31 server listening (udp)

     Using this verbosity level can be a useful way to check the
     effects of the growth factor used on slabs with different memory
     allocations, which in turn can be used to better tune the growth
     factor to suit the data you are storing in the cache. For example,
     if you set the growth factor to 4 (quadrupling the size of each
     slab):

          shell> memcached -f 4 -m 1g -vv
          slab class   1: chunk size     80 perslab 13107
          slab class   2: chunk size    320 perslab  3276
          slab class   3: chunk size   1280 perslab   819
          slab class   4: chunk size   5120 perslab   204
          slab class   5: chunk size  20480 perslab    51
          slab class   6: chunk size  81920 perslab    12
          slab class   7: chunk size 327680 perslab     3
          ...

     During use of the cache, this verbosity level also prints out
     detailed information on the storage and recovery of keys and other
     information. An example of the output during a typical set/get and
     increment/decrement operation is shown below.

          32: Client using the ascii protocol
          <32 set my_key 0 0 10
          >32 STORED
          <32 set object_key 1 0 36
          >32 STORED
          <32 get my_key
          >32 sending key my_key
          >32 END
          <32 get object_key
          >32 sending key object_key
          >32 END
          <32 set key 0 0 6
          >32 STORED
          <32 incr key 1
          >32 789544
          <32 decr key 1
          >32 789543
          <32 incr key 2
          >32 789545
          <32 set my_key 0 0 10
          >32 STORED
          <32 set object_key 1 0 36
          >32 STORED
          <32 get my_key
          >32 sending key my_key
          >32 END
          <32 get object_key
          >32 sending key object_key1 1 36

          >32 END
          <32 set key 0 0 6
          >32 STORED
          <32 incr key 1
          >32 789544
          <32 decr key 1
          >32 789543
          <32 incr key 2
          >32 789545

     During client communication, for each line, the initial character
     shows the direction of flow of the information.  The < for
     communication from the client to the `memcached' server and > for
     communication back to the client. The number is the numeric socket
     descriptor for the connection.

   * *Output when using `-vvv'*

     This level of verbosity includes the transitions of connections
     between different states in the event library while reading and
     writing content to/from the clients. It should be used to diagnose
     and identify issues in client communication. For example, you can
     use this information to determine if `memcached' is taking a long
     time to return information to the client, during the read of the
     client operation or before returning and completing the operation.
     An example of the typical sequence for a set operation is provided
     below:

          <32 new auto-negotiating client connection
          32: going from conn_new_cmd to conn_waiting
          32: going from conn_waiting to conn_read
          32: going from conn_read to conn_parse_cmd
          32: Client using the ascii protocol
          <32 set my_key 0 0 10
          32: going from conn_parse_cmd to conn_nread
          > NOT FOUND my_key
          >32 STORED
          32: going from conn_nread to conn_write
          32: going from conn_write to conn_new_cmd
          32: going from conn_new_cmd to conn_waiting
          32: going from conn_waiting to conn_read
          32: going from conn_read to conn_closing
          <32 connection closed.

All of the verbosity levels in `memcached' are designed to be used
during debugging or examination of issues.  The quantity of information
generated, particularly when using `-vvv', is significant, particularly
on a busy server. Also be aware that writing the error information out,
especially to disk, may negate some of the performance gains you
achieve by using `memcached'. Therefore, use in production or
deployment environments is not recommended.


File: manual.info,  Node: ha-memcached-interfaces,  Next: ha-memcached-stats,  Prev: ha-memcached-using,  Up: ha-memcached

15.6.3 `memcached' Interfaces
-----------------------------

* Menu:

* ha-memcached-interfaces-libmemcached::  Using `libmemcached'
* ha-memcached-interfaces-perl::  Using MySQL and `memcached' with Perl
* ha-memcached-interfaces-python::  Using MySQL and `memcached' with Python
* ha-memcached-interfaces-php::  Using MySQL and `memcached' with PHP
* ha-memcached-interfaces-ruby::  Using MySQL and `memcached' with Ruby
* ha-memcached-interfaces-java::  Using MySQL and `memcached' with Java
* ha-memcached-interfaces-mysqludf::  Using the MySQL `memcached' UDFs
* ha-memcached-interfaces-protocol::  `memcached' Protocol

A number of interfaces from different languages exist for interacting
with `memcached' servers and storing and retrieving information.
Interfaces for the most common language platforms including Perl, PHP,
Python, Ruby, C and Java.

Data stored into a `memcached' server is referred to by a single string
(the key), with storage into the cache and retrieval from the cache
using the key as the reference. The cache therefore operates like a
large associative array or hash. It is not possible to structure or
otherwise organize the information stored in the cache. To store
information in a structured way, you must use 'formatted' keys.

The following tips may be useful to you when using `memcached':

The general sequence for using `memcached' in any language as a caching
solution is as follows:

  1. Request the item from the cache.

  2. If the item exists, use the item data.

  3. If the item does not exist, load the data from MySQL, and store
     the value into the cache. This means the value is available to the
     next client that requests it from the cache.

For a flow diagram of this sequence, see *Note
ha-memcached-fig-basicflow::.

FIGURE GOES HERE: Typical `memcached' Application Flowchart

The interface to `memcached' supports the following methods for storing
and retrieving information in the cache, and these are consistent
across all the different APIs, even though the language specific
mechanics may be different:

   * `get(key)': Retrieves information from the cache. Returns the
     value if it exists, or `NULL', `nil', or `undefined' or the
     closest equivalent in the corresponding language, if the specified
     key does not exist.

   * `set(key, value [, expiry])': Sets the key in the cache to the
     specified value. Note that this either updates an existing key if
     it already exists, or adds a new key/value pair if the key doesn't
     exist. If the expiry time is specified, then the key expires (and
     is deleted) when the expiry time is reached. The time is specified
     in seconds, and is taken as a relative time if the value is less
     than 30 days (30*24*60*60), or an absolute time (epoch) if larger
     than this value.

   * `add(key, value [, expiry])': Adds the key to the cache, if the
     specified key doesn't already exist.

   * `replace(key, value [, expiry])': Replaces the `value' of the
     specified `key', only if the key already exists.

   * `delete(key [, time])': Deletes the `key' from the cache. If you
     supply a `time', then adding a value with the specified `key' is
     blocked for the specified period.

   * `incr(key [, value])': Increments the specified `key' by one or
     the specified `value'.

   * `decr(key [, value])': Decrements the specified `key' by one or
     the specified `value'.

   * `flush_all': Invalidates (or expires) all the current items in the
     cache. Technically they still exist (they are not deleted), but
     they are silently destroyed the next time you try to access them.

In all implementations, most or all of these functions are duplicated
through the corresponding native language interface.

For all languages and interfaces, use `memcached' to store full items,
rather than simply caching single rows of information from the
database. For example, when displaying a record about an object
(invoice, user history, or blog post), load all the data for the
associated entry from the database, and compile it into the internal
structure that would normally be required by the application. You then
save the complete object into the cache.

Complex data structures cannot be stored directly. Most interfaces
serialize the data for you, that is, put it in a form that can
reconstruct the original pointers and nesting. Perl uses `Storable',
PHP uses `serialize', Python uses `cPickle' (or `Pickle') and Java uses
the `Serializable' interface. In most cases, the serialization
interface used is customizable. To share data stored in `memcached'
instances between different language interfaces, consider using a
common serialization solution such as JSON (Javascript Object Notation).


File: manual.info,  Node: ha-memcached-interfaces-libmemcached,  Next: ha-memcached-interfaces-perl,  Prev: ha-memcached-interfaces,  Up: ha-memcached-interfaces

15.6.3.1 Using `libmemcached'
.............................

* Menu:

* ha-memcached-interfaces-libmemcached-base::  `libmemcached' Base Functions
* ha-memcached-interfaces-libmemcached-servers::  `libmemcached' Server Functions
* ha-memcached-interfaces-libmemcached-set::  `libmemcached' Set Functions
* ha-memcached-interfaces-libmemcached-get::  `libmemcached' Get Functions
* ha-memcached-interfaces-libmemcached-behaviors::  `libmemcached' Behaviors
* ha-memcached-interfaces-libmemcached-utilities::  `libmemcached' Command-line Utilities

The `libmemcached' library provides both C and C++ interfaces to
`memcached' and is also the basis for a number of different additional
API implementations, including Perl, Python and Ruby. Understanding the
core `libmemcached' functions can help when using these other
interfaces.

The C library is the most comprehensive interface library for
`memcached' and provides a wealth of functions and operational systems
not always exposed in the other interfaces not based on the
`libmemcached' library.

The different functions can be divided up according to their basic
operation. In addition to functions that interface to the core API,
there are a number of utility functions that provide extended
functionality, such as appending and prepending data.

To build and install `libmemcached', download the `libmemcached'
package, run configure, and then build and install:

     shell> tar xjf libmemcached-0.21.tar.gz
     shell> cd libmemcached-0.21
     shell> ./configure
     shell> make
     shell> make install

On many Linux operating systems, you can install the corresponding
`libmemcached' package through the usual `yum', `apt-get' or similar
commands.

To build an application that uses the library, first set the list of
servers. Either directly manipulate the servers configured within the
main `memcached_st' structure, or separately populate a list of
servers, and then add this list to the `memcached_st' structure.  The
latter method is used in the following example. Once the server list
has been set, you can call the functions to store or retrieve data. A
simple application for setting a preset value to `localhost' is
provided here:

     #include <stdio.h>
     #include <string.h>
     #include <unistd.h>
     #include <libmemcached/memcached.h>

     int main(int argc, char *argv[])
     {
       memcached_server_st *servers = NULL;
       memcached_st *memc;
       memcached_return rc;
       char *key= "keystring";
       char *value= "keyvalue";

       memcached_server_st *memcached_servers_parse (char *server_strings);
       memc= memcached_create(NULL);

       servers= memcached_server_list_append(servers, "localhost", 11211, &rc);
       rc= memcached_server_push(memc, servers);

       if (rc == MEMCACHED_SUCCESS)
         fprintf(stderr,"Added server successfully\n");
       else
         fprintf(stderr,"Couldn't add server: %s\n",memcached_strerror(memc, rc));

       rc= memcached_set(memc, key, strlen(key), value, strlen(value), (time_t)0, (uint32_t)0);

       if (rc == MEMCACHED_SUCCESS)
         fprintf(stderr,"Key stored successfully\n");
       else
         fprintf(stderr,"Couldn't store key: %s\n",memcached_strerror(memc, rc));

       return 0;
     }

You can test the success of an operation by using the return value, or
populated result code, for a given function. The value is always set to
`MEMCACHED_SUCCESS' if the operation succeeded. In the event of a
failure, use the `memcached_strerror()' function to translate the
result code into a printable string.

To build the application, you must specify the `memcached' library:

     shell> gcc -o memc_basic memc_basic.c -lmemcached

Running the above sample application, after starting a `memcached'
server, should return a success message:

     shell> memc_basic
     Added server successfully
     Key stored successfully


File: manual.info,  Node: ha-memcached-interfaces-libmemcached-base,  Next: ha-memcached-interfaces-libmemcached-servers,  Prev: ha-memcached-interfaces-libmemcached,  Up: ha-memcached-interfaces-libmemcached

15.6.3.2 `libmemcached' Base Functions
......................................

The base `libmemcached' functions enable you to create, destroy and
clone the main `memcached_st' structure that is used to interface to
the `memcached' servers. The main functions are defined below:

     memcached_st *memcached_create (memcached_st *ptr);

Creates a new `memcached_st' structure for use with the other
`libmemcached' API functions. You can supply an existing, static,
`memcached_st' structure, or `NULL' to have a new structured allocated.
Returns a pointer to the created structure, or `NULL' on failure.

     void memcached_free (memcached_st *ptr);

Free the structure and memory allocated to a previously created
`memcached_st' structure.

     memcached_st *memcached_clone(memcached_st *clone, memcached_st *source);

Clone an existing `memcached' structure from the specified `source',
copying the defaults and list of servers defined in the structure.


File: manual.info,  Node: ha-memcached-interfaces-libmemcached-servers,  Next: ha-memcached-interfaces-libmemcached-set,  Prev: ha-memcached-interfaces-libmemcached-base,  Up: ha-memcached-interfaces-libmemcached

15.6.3.3 `libmemcached' Server Functions
........................................

The `libmemcached' API uses a list of servers, stored within the
`memcached_server_st' structure, to act as the list of servers used by
the rest of the functions. To use `memcached', you first create the
server list, and then apply the list of servers to a valid
`libmemcached' object.

Because the list of servers, and the list of servers within an active
`libmemcached' object can be manipulated separately, you can update and
manage server lists while an active `libmemcached' interface is running.

The functions for manipulating the list of servers within a
`memcached_st' structure are given below:

     memcached_return
                memcached_server_add (memcached_st *ptr,
                                      char *hostname,
                                      unsigned int port);

Add a server, using the given `hostname' and `port' into the
`memcached_st' structure given in `ptr'.

     memcached_return
                memcached_server_add_unix_socket (memcached_st *ptr,
                                                  char *socket);

Add a Unix socket to the list of servers configured in the
`memcached_st' structure.

     unsigned int memcached_server_count (memcached_st *ptr);

Return a count of the number of configured servers within the
`memcached_st' structure.

     memcached_server_st *
                memcached_server_list (memcached_st *ptr);

Returns an array of all the defined hosts within a `memcached_st'
structure.

     memcached_return
                memcached_server_push (memcached_st *ptr,
                                       memcached_server_st *list);

Pushes an existing list of servers onto list of servers configured for
a current `memcached_st' structure. This adds servers to the end of the
existing list, and duplicates are not checked.

The `memcached_server_st' structure can be used to create a list of
`memcached' servers which can then be applied individually to
`memcached_st' structures.

     memcached_server_st *
                memcached_server_list_append (memcached_server_st *ptr,
                                              char *hostname,
                                              unsigned int port,
                                              memcached_return *error);

Add a server, with `hostname' and `port', to the server list in `ptr'.
The result code is handled by the `error' argument, which should point
to an existing `memcached_return' variable. The function returns a
pointer to the returned list.

      unsigned int memcached_server_list_count (memcached_server_st *ptr);

Return the number of the servers in the server list.

     void memcached_server_list_free (memcached_server_st *ptr);

Free up the memory associated with a server list.

     memcached_server_st *memcached_servers_parse (char *server_strings);

Parses a string containing a list of servers, where individual servers
are separated by a comma, space, or both, and where individual servers
are of the form `server[:port]'. The return value is a server list
structure.


File: manual.info,  Node: ha-memcached-interfaces-libmemcached-set,  Next: ha-memcached-interfaces-libmemcached-get,  Prev: ha-memcached-interfaces-libmemcached-servers,  Up: ha-memcached-interfaces-libmemcached

15.6.3.4 `libmemcached' Set Functions
.....................................

The set related functions within `libmemcached' provide the same
functionality as the core functions supported by the `memcached'
protocol. The full definition for the different functions is the same
for all the base functions (add, replace, prepend, append). For
example, the function definition for `memcached_set()' is:

     memcached_return
                memcached_set (memcached_st *ptr,
                               const char *key,
                               size_t key_length,
                               const char *value,
                               size_t value_length,
                               time_t expiration,
                               uint32_t flags);

The `ptr' is the `memcached_st' structure. The `key' and `key_length'
define the key name and length, and `value' and `value_length' the
corresponding value and length. You can also set the expiration and
optional flags. For more information, see *Note
ha-memcached-interfaces-libmemcached-behaviors::.

The following table outlines the remainder of the set-related functions.

`libmemcached' Function              Equivalent to
`memcached_set(memc, key,            Generic `set()' operation.
key_length, value, value_length,     
expiration, flags)'                  
`memcached_add(memc, key,            Generic `add()' function.
key_length, value, value_length,     
expiration, flags)'                  
`memcached_replace(memc, key,        Generic `replace()'.
key_length, value, value_length,     
expiration, flags)'                  
`memcached_prepend(memc, key,        Prepends the specified `value'
key_length, value, value_length,     before the current value of the
expiration, flags)'                  specified `key'.
`memcached_append(memc, key,         Appends the specified `value' after
key_length, value, value_length,     the current value of the specified
expiration, flags)'                  `key'.
`memcached_cas(memc, key,            Overwrites the data for a given key
key_length, value, value_length,     as long as the corresponding `cas'
expiration, flags, cas)'             value is still the same within the
                                     server.
`memcached_set_by_key(memc,          Similar to the generic `set()', but
master_key, master_key_length, key,  has the option of an additional
key_length, value, value_length,     master key that can be used to
expiration, flags)'                  identify an individual server.
`memcached_add_by_key(memc,          Similar to the generic `add()', but
master_key, master_key_length, key,  has the option of an additional
key_length, value, value_length,     master key that can be used to
expiration, flags)'                  identify an individual server.
`memcached_replace_by_key(memc,      Similar to the generic `replace()',
master_key, master_key_length, key,  but has the option of an additional
key_length, value, value_length,     master key that can be used to
expiration, flags)'                  identify an individual server.
`memcached_prepend_by_key(memc,      Similar to the
master_key, master_key_length, key,  `memcached_prepend()', but has the
key_length, value, value_length,     option of an additional master key
expiration, flags)'                  that can be used to identify an
                                     individual server.
`memcached_append_by_key(memc,       Similar to the
master_key, master_key_length, key,  `memcached_append()', but has the
key_length, value, value_length,     option of an additional master key
expiration, flags)'                  that can be used to identify an
                                     individual server.
`memcached_cas_by_key(memc,          Similar to the `memcached_cas()',
master_key, master_key_length, key,  but has the option of an additional
key_length, value, value_length,     master key that can be used to
expiration, flags)'                  identify an individual server.

The `by_key' methods add two further arguments, the master key, to be
used and applied during the hashing stage for selecting the servers.
You can see this in the following definition:

     memcached_return
                memcached_set_by_key(memcached_st *ptr,
                                     const char *master_key,
                                     size_t master_key_length,
                                     const char *key,
                                     size_t key_length,
                                     const char *value,
                                     size_t value_length,
                                     time_t expiration,
                                     uint32_t flags);

All the functions return a value of type `memcached_return', which you
can compare against the `MEMCACHED_SUCCESS' constant.


File: manual.info,  Node: ha-memcached-interfaces-libmemcached-get,  Next: ha-memcached-interfaces-libmemcached-behaviors,  Prev: ha-memcached-interfaces-libmemcached-set,  Up: ha-memcached-interfaces-libmemcached

15.6.3.5 `libmemcached' Get Functions
.....................................

The `libmemcached' functions provide both direct access to a single
item, and a multiple-key request mechanism that provides much faster
responses when fetching a large number of keys simultaneously.

The main get-style function, which is equivalent to the generic `get()'
is `memcached_get()'. The functions a string pointer to the returned
value for a corresponding key.

     char *memcached_get (memcached_st *ptr,
                          const char *key, size_t key_length,
                          size_t *value_length,
                          uint32_t *flags,
                          memcached_return *error);

A multi-key get, `memcached_mget()', is also available. Using a
multiple key get operation is much quicker to do in one block than
retrieving the key values with individual calls to `memcached_get()'. To
start the multi-key get, call `memcached_mget()':

     memcached_return
              memcached_mget (memcached_st *ptr,
                              char **keys, size_t *key_length,
                              unsigned int number_of_keys);

The return value is the success of the operation. The `keys' parameter
should be an array of strings containing the keys, and `key_length' an
array containing the length of each corresponding key.
`number_of_keys' is the number of keys supplied in the array.

To fetch the individual values, use `memcached_fetch()' to get each
corresponding value.

     char *memcached_fetch (memcached_st *ptr,
                              const char *key, size_t *key_length,
                              size_t *value_length,
                              uint32_t *flags,
                              memcached_return *error);

The function returns the key value, with the `key', `key_length' and
`value_length' parameters being populated with the corresponding key
and length information. The function returns `NULL' when there are no
more values to be returned. A full example, including the populating of
the key data and the return of the information is provided here.

     #include <stdio.h>
     #include <sstring.h>
     #include <unistd.h>
     #include <libmemcached/memcached.h>

     int main(int argc, char *argv[])
     {
       memcached_server_st *servers = NULL;
       memcached_st *memc;
       memcached_return rc;
       char *keys[]= {"huey", "dewey", "louie"};
       size_t key_length[3];
       char *values[]= {"red", "blue", "green"};
       size_t value_length[3];
       unsigned int x;
       uint32_t flags;

       char return_key[MEMCACHED_MAX_KEY];
       size_t return_key_length;
       char *return_value;
       size_t return_value_length;

       memc= memcached_create(NULL);

       servers= memcached_server_list_append(servers, "localhost", 11211, &rc);
       rc= memcached_server_push(memc, servers);

       if (rc == MEMCACHED_SUCCESS)
         fprintf(stderr,"Added server successfully\n");
       else
         fprintf(stderr,"Couldn't add server: %s\n",memcached_strerror(memc, rc));

       for(x= 0; x < 3; x++)
         {
           key_length[x] = strlen(keys[x]);
           value_length[x] = strlen(values[x]);

           rc= memcached_set(memc, keys[x], key_length[x], values[x],
                             value_length[x], (time_t)0, (uint32_t)0);
           if (rc == MEMCACHED_SUCCESS)
             fprintf(stderr,"Key %s stored successfully\n",keys[x]);
           else
             fprintf(stderr,"Couldn't store key: %s\n",memcached_strerror(memc, rc));
         }

       rc= memcached_mget(memc, keys, key_length, 3);

       if (rc == MEMCACHED_SUCCESS)
         {
           while ((return_value= memcached_fetch(memc, return_key, &return_key_length,
                                                 &return_value_length, &flags, &rc)) != NULL)
             {
               if (rc == MEMCACHED_SUCCESS)
                 {
                   fprintf(stderr,"Key %s returned %s\n",return_key, return_value);
                 }
             }
         }

       return 0;
     }

Running the above application:

     shell> memc_multi_fetch
     Added server successfully
     Key huey stored successfully
     Key dewey stored successfully
     Key louie stored successfully
     Key huey returned red
     Key dewey returned blue
     Key louie returned green


File: manual.info,  Node: ha-memcached-interfaces-libmemcached-behaviors,  Next: ha-memcached-interfaces-libmemcached-utilities,  Prev: ha-memcached-interfaces-libmemcached-get,  Up: ha-memcached-interfaces-libmemcached

15.6.3.6 `libmemcached' Behaviors
.................................

The behavior of `libmemcached' can be modified by setting one or more
behavior flags. These can either be set globally, or they can be
applied during the call to individual functions. Some behaviors also
accept an additional setting, such as the hashing mechanism used when
selecting servers.

To set global behaviors:

     memcached_return
                memcached_behavior_set (memcached_st *ptr,
                                        memcached_behavior flag,
                                        uint64_t data);

To get the current behavior setting:

     uint64_t
                memcached_behavior_get (memcached_st *ptr,
                                        memcached_behavior flag);

Behavior                      Description
`MEMCACHED_BEHAVIOR_NO_BLOCK' Caused `libmemcached' to use asynchronous
                              I/O.
`MEMCACHED_BEHAVIOR_TCP_NODELAY'Turns on no-delay for network sockets.
`MEMCACHED_BEHAVIOR_HASH'     Without a value, sets the default hashing
                              algorithm for keys to use MD5.  Other
                              valid values include
                              `MEMCACHED_HASH_DEFAULT',
                              `MEMCACHED_HASH_MD5', `MEMCACHED_HASH_CRC',
                              `MEMCACHED_HASH_FNV1_64',
                              `MEMCACHED_HASH_FNV1A_64',
                              `MEMCACHED_HASH_FNV1_32', and
                              `MEMCACHED_HASH_FNV1A_32'.
`MEMCACHED_BEHAVIOR_DISTRIBUTION'Changes the method of selecting the server
                              used to store a given value.  The default
                              method is `MEMCACHED_DISTRIBUTION_MODULA'.
                              You can enable consistent hashing by
                              setting
                              `MEMCACHED_DISTRIBUTION_CONSISTENT'.
                              `MEMCACHED_DISTRIBUTION_CONSISTENT' is an
                              alias for the value
                              `MEMCACHED_DISTRIBUTION_CONSISTENT_KETAMA'.
`MEMCACHED_BEHAVIOR_CACHE_LOOKUPS'Cache the lookups made to the DNS service.
                              This can improve the performance if you
                              are using names instead of IP addresses
                              for individual hosts.
`MEMCACHED_BEHAVIOR_SUPPORT_CAS'Support CAS operations. By default, this
                              is disabled because it imposes a
                              performance penalty.
`MEMCACHED_BEHAVIOR_KETAMA'   Sets the default distribution to
                              `MEMCACHED_DISTRIBUTION_CONSISTENT_KETAMA'
                              and the hash to `MEMCACHED_HASH_MD5'.
`MEMCACHED_BEHAVIOR_POLL_TIMEOUT'Modify the timeout value used by `poll()'.
                              Supply a `signed int' pointer for the
                              timeout value.
`MEMCACHED_BEHAVIOR_BUFFER_REQUESTS'Buffers IO requests instead of them being
                              sent. A get operation, or closing the
                              connection causes the data to be flushed.
`MEMCACHED_BEHAVIOR_VERIFY_KEY'Forces `libmemcached' to verify that a
                              specified key is valid.
`MEMCACHED_BEHAVIOR_SORT_HOSTS'If set, hosts added to the list of
                              configured hosts for a `memcached_st'
                              structure are placed into the host list in
                              sorted order. This breaks consistent
                              hashing if that behavior has been enabled.
`MEMCACHED_BEHAVIOR_CONNECT_TIMEOUT'In nonblocking mode this changes the value
                              of the timeout during socket connection.


File: manual.info,  Node: ha-memcached-interfaces-libmemcached-utilities,  Prev: ha-memcached-interfaces-libmemcached-behaviors,  Up: ha-memcached-interfaces-libmemcached

15.6.3.7 `libmemcached' Command-line Utilities
..............................................

In addition to the main C library interface, `libmemcached' also
includes a number of command line utilities that can be useful when
working with and debugging `memcached' applications.

All of the command line tools accept a number of arguments, the most
critical of which is `servers', which specifies the list of servers to
connect to when returning information.

The main tools are:

   * `memcat': Display the value for each ID given on the command line:

          shell> memcat --servers=localhost hwkey
          Hello world

   * `memcp': Copy the contents of a file into the cache, using the
     file names as the key:

          shell> echo "Hello World" > hwkey
          shell> memcp --servers=localhost hwkey
          shell> memcat --servers=localhost hwkey
          Hello world

   * `memrm': Remove an item from the cache:

          shell> memcat --servers=localhost hwkey
          Hello world
          shell> memrm --servers=localhost hwkey
          shell> memcat --servers=localhost hwkey

   * `memslap': Test the load on one or more `memcached' servers,
     simulating get/set and multiple client operations. For example,
     you can simulate the load of 100 clients performing get operations:

          shell> memslap --servers=localhost --concurrency=100 --flush --test=get
          memslap --servers=localhost --concurrency=100 --flush --test=get	Threads connecting to servers 100
          	Took 13.571 seconds to read data

   * `memflush': Flush (empty) the contents of the `memcached' cache.

          shell> memflush --servers=localhost


File: manual.info,  Node: ha-memcached-interfaces-perl,  Next: ha-memcached-interfaces-python,  Prev: ha-memcached-interfaces-libmemcached,  Up: ha-memcached-interfaces

15.6.3.8 Using MySQL and `memcached' with Perl
..............................................

The `Cache::Memcached' module provides a native interface to the
Memcache protocol, and provides support for the core functions offered
by `memcached'. You should install the module using your hosts native
package management system. Alternatively, you can install the module
using `CPAN':

     root-shell> perl -MCPAN -e 'install Cache::Memcached'

To use `memcached' from Perl through the `Cache::Memcached' module,
first create a new `Cache::Memcached' object that defines the list of
servers and other parameters for the connection. The only argument is a
hash containing the options for the cache interface. For example, to
create a new instance that uses three `memcached' servers:

     use Cache::Memcached;

     my $cache = new Cache::Memcached {
         'servers' => [
             '192.168.0.100:11211',
             '192.168.0.101:11211',
             '192.168.0.102:11211',
     	],
     };

*Note*:

When using the `Cache::Memcached' interface with multiple servers, the
API automatically performs certain operations across all the servers in
the group. For example, getting statistical information through
`Cache::Memcached' returns a hash that contains data on a host by host
basis, as well as generalized statistics for all the servers in the
group.

You can set additional properties on the cache object instance when it
is created by specifying the option as part of the option hash.
Alternatively, you can use a corresponding method on the instance:

   * `servers' or method `set_servers()': Specifies the list of the
     servers to be used. The servers list should be a reference to an
     array of servers, with each element as the address and port number
     combination (separated by a colon). You can also specify a local
     connection through a UNIX socket (for example
     `/tmp/sock/memcached'). You can also specify the server with a
     weight (indicating how much more frequently the server should be
     used during hashing) by specifying an array reference with the
     `memcached' server instance and a weight number. Higher numbers
     give higher priority.

   * `compress_threshold' or method `set_compress_threshold()':
     Specifies the threshold when values are compressed. Values larger
     than the specified number are automatically compressed (using
     `zlib') during storage and retrieval.

   * `no_rehash' or method `set_norehash()': Disables finding a new
     server if the original choice is unavailable.

   * `readonly' or method `set_readonly()': Disables writes to the
     `memcached' servers.

Once the `Cache::Memcached' object instance has been configured you can
use the `set()' and `get()' methods to store and retrieve information
from the `memcached' servers.  Objects stored in the cache are
automatically serialized and deserialized using the `Storable' module.

The `Cache::Memcached' interface supports the following methods for
storing/retrieving data, and relate to the generic methods as shown in
the table.

`Cache::Memcached' Function          Equivalent to
`get()'                              Generic `get()'
`get_multi(keys)'                    Gets multiple `keys' from memcache
                                     using just one query. Returns a
                                     hash reference of key/value pairs.
`set()'                              Generic `set()'
`add()'                              Generic `add()'
`replace()'                          Generic `replace()'
`delete()'                           Generic `delete()'
`incr()'                             Generic `incr()'
`decr()'                             Generic `decr()'

Below is a complete example for using `memcached' with Perl and the
`Cache::Memcached' module:

     #!/usr/bin/perl

     use Cache::Memcached;
     use DBI;
     use Data::Dumper;

     # Configure the memcached server

     my $cache = new Cache::Memcached {
         'servers' => [
                        'localhost:11211',
                        ],
         };

     # Get the film name from the command line
     # memcached keys must not contain spaces, so create
     # a key name by replacing spaces with underscores

     my $filmname = shift or die "Must specify the film name\n";
     my $filmkey = $filmname;
     $filmkey =~ s/ /_/;

     # Load the data from the cache

     my $filmdata = $cache->get($filmkey);

     # If the data wasn't in the cache, then we load it from the database

     if (!defined($filmdata))
     {
         $filmdata = load_filmdata($filmname);

         if (defined($filmdata))
         {

     # Set the data into the cache, using the key

     	if ($cache->set($filmkey,$filmdata))
             {
                 print STDERR "Film data loaded from database and cached\n";
             }
             else
             {
                 print STDERR "Couldn't store to cache\n";
     	}
         }
         else
         {
          	die "Couldn't find $filmname\n";
         }
     }
     else
     {
         print STDERR "Film data loaded from Memcached\n";
     }

     sub load_filmdata
     {
         my ($filmname) = @_;

         my $dsn = "DBI:mysql:database=sakila;host=localhost;port=3306";

         $dbh = DBI->connect($dsn, 'sakila','password');

         my ($filmbase) = $dbh->selectrow_hashref(sprintf('select * from film where title = %s',
                                                          $dbh->quote($filmname)));

         if (!defined($filmname))
         {
          	return (undef);
         }

         $filmbase->{stars} =
     	$dbh->selectall_arrayref(sprintf('select concat(first_name," ",last_name) ' .
                                              'from film_actor left join (actor) ' .
                                              'on (film_actor.actor_id = actor.actor_id) ' .
                                              ' where film_id=%s',
                                              $dbh->quote($filmbase->{film_id})));

         return($filmbase);
     }

The example uses the Sakila database, obtaining film data from the
database and writing a composite record of the film and actors to
memcache. When calling it for a film does not exist, you get this
result:

     shell> memcached-sakila.pl "ROCK INSTINCT"
     Film data loaded from database and cached

When accessing a film that has already been added to the cache:

     shell> memcached-sakila.pl "ROCK INSTINCT"
     Film data loaded from Memcached


File: manual.info,  Node: ha-memcached-interfaces-python,  Next: ha-memcached-interfaces-php,  Prev: ha-memcached-interfaces-perl,  Up: ha-memcached-interfaces

15.6.3.9 Using MySQL and `memcached' with Python
................................................

The Python `memcache' module interfaces to `memcached' servers, and is
written in pure python (that is, without using one of the C APIs). You
can download and install a copy from Python Memcached
(http://www.tummy.com/Community/software/python-memcached/).

To install, download the package and then run the Python installer:

     python setup.py install
     running install
     running bdist_egg
     running egg_info
     creating python_memcached.egg-info
     ...
     removing 'build/bdist.linux-x86_64/egg' (and everything under it)
     Processing python_memcached-1.43-py2.4.egg
     creating /usr/lib64/python2.4/site-packages/python_memcached-1.43-py2.4.egg
     Extracting python_memcached-1.43-py2.4.egg to /usr/lib64/python2.4/site-packages
     Adding python-memcached 1.43 to easy-install.pth file

     Installed /usr/lib64/python2.4/site-packages/python_memcached-1.43-py2.4.egg
     Processing dependencies for python-memcached==1.43
     Finished processing dependencies for python-memcached==1.43

Once installed, the `memcache' module provides a class-based interface
to your `memcached' servers. Serialization of Python structures is
handled by using the Python `cPickle' or `pickle' modules.

To create a new `memcache' interface, import the `memcache' module and
create a new instance of the `memcache.Client' class:

     import memcache
     memc = memcache.Client(['127.0.0.1:11211'])

The first argument should be an array of strings containing the server
and port number for each `memcached' instance to use. You can enable
debugging by setting the optional `debug' parameter to 1.

By default, the hashing mechanism used is `crc32'. This provides a
basic module hashing algorithm for selecting among multiple servers.
You can change the function used by setting the value of
`memcache.serverHashFunction' to the alternate function to use. For
example:

     from zlib import adler32
     memcache.serverHashFunction = adler32

Once you have defined the servers to use within the `memcache'
instance, the core functions provide the same functionality as in the
generic interface specification. A summary of the supported functions
is provided in the following table.

Python `memcache' Function           Equivalent to
`get()'                              Generic `get()'
`get_multi(keys)'                    Gets multiple values from the
                                     supplied array of `keys'.  Returns
                                     a hash reference of key/value pairs.
`set()'                              Generic `set()'
`set_multi(dict [, expiry [,         Sets multiple key/value pairs from
key_prefix]])'                       the supplied `dict'.
`add()'                              Generic `add()'
`replace()'                          Generic `replace()'
`prepend(key, value [, expiry])'     Prepends the supplied `value' to
                                     the value of the existing `key'.
`append(key, value [, expiry[)'      Appends the supplied `value' to the
                                     value of the existing `key'.
`delete()'                           Generic `delete()'
`delete_multi(keys [, expiry [,      Deletes all the keys from the hash
key_prefix]] )'                      matching each string in the array
                                     `keys'.
`incr()'                             Generic `incr()'
`decr()'                             Generic `decr()'

*Note*:

Within the Python `memcache' module, all the `*_multi()'functions
support an optional `key_prefix' parameter. If supplied, then the
string is used as a prefix to all key lookups. For example, if you call:

     memc.get_multi(['a','b'], key_prefix='users:')

The function retrieves the keys `users:a' and `users:b' from the
servers.

An example showing the storage and retrieval of information to a
`memcache' instance, loading the raw data from MySQL, is shown below:

     import sys
     import MySQLdb
     import memcache

     memc = memcache.Client(['127.0.0.1:11211'], debug=1);

     try:
         conn = MySQLdb.connect (host = "localhost",
                                 user = "sakila",
                                 passwd = "password",
                                 db = "sakila")
     except MySQLdb.Error, e:
          print "Error %d: %s" % (e.args[0], e.args[1])
          sys.exit (1)

     popularfilms = memc.get('top5films')

     if not popularfilms:
         cursor = conn.cursor()
         cursor.execute('select film_id,title from film order by rental_rate desc limit 5')
         rows = cursor.fetchall()
         memc.set('top5films',rows,60)
         print "Updated memcached with MySQL data"
     else:
         print "Loaded data from memcached"
         for row in popularfilms:
             print "%s, %s" % (row[0], row[1])

When executed for the first time, the data is loaded from the MySQL
database and stored to the `memcached' server.

     shell> python memc_python.py
     Updated memcached with MySQL data

The data is automatically serialized using `cPickle'/`pickle'. This
means when you load the data back from `memcached', you can use the
object directly. In the example above, the information stored to
`memcached' is in the form of rows from a Python DB cursor. When
accessing the information (within the 60 second expiry time), the data
is loaded from `memcached' and dumped:

     shell> python memc_python.py
     Loaded data from memcached
     2, ACE GOLDFINGER
     7, AIRPLANE SIERRA
     8, AIRPORT POLLOCK
     10, ALADDIN CALENDAR
     13, ALI FOREVER

The serialization and deserialization happens automatically, but be
aware that serialization of Python data may be incompatible with other
interfaces and languages. You can change the serialization module used
during initialization, for example to use JSON, which is more easily
exchanged.


File: manual.info,  Node: ha-memcached-interfaces-php,  Next: ha-memcached-interfaces-ruby,  Prev: ha-memcached-interfaces-python,  Up: ha-memcached-interfaces

15.6.3.10 Using MySQL and `memcached' with PHP
..............................................

PHP provides support for the Memcache functions through a PECL
extension. To enable the PHP `memcache' extensions, you must build PHP
using the `--enable-memcache' option to `configure' when building from
source.

If you are installing on a Red Hat based server, you can install the
`php-pecl-memcache' RPM:

     root-shell> yum --install php-pecl-memcache

On Debian based distributions, use the `php-memcache' package.

You can set global runtime configuration options by specifying the
values in the following table within your `php.ini' file.

Configuration option      Default        Description
`memcache.allow_failover' 1              Specifies whether another
                                         server in the list should be
                                         queried if the first server
                                         selected fails.
`memcache.max_failover_attempts'20             Specifies the number of servers
                                         to try before returning a
                                         failure.
`memcache.chunk_size'     8192           Defines the size of network
                                         chunks used to exchange data
                                         with the `memcached' server.
`memcache.default_port'   11211          Defines the default port to use
                                         when communicating with the
                                         `memcached' servers.
`memcache.hash_strategy'  standard       Specifies which hash strategy
                                         to use. Set to `consistent' to
                                         enable servers to be added or
                                         removed from the pool without
                                         causing the keys to be remapped
                                         to other servers. When set to
                                         `standard', an older (modula)
                                         strategy is used that
                                         potentially uses different
                                         servers for storage.
`memcache.hash_function'  crc32          Specifies which function to use
                                         when mapping keys to servers.
                                         `crc32' uses the standard CRC32
                                         hash.  `fnv' uses the FNV-1a
                                         hashing algorithm.

To create a connection to a `memcached' server, create a new `Memcache'
object and then specify the connection options. For example:

     <?php

     $cache = new Memcache;
     $cache->connect('localhost',11211);
     ?>

This opens an immediate connection to the specified server.

To use multiple `memcached' servers, you need to add servers to the
memcache object using `addServer()':

     bool Memcache::addServer ( string $host [, int $port [, bool $persistent
                      [, int $weight [, int $timeout [, int $retry_interval
                      [, bool $status [, callback $failure_callback
                      ]]]]]]] )

The server management mechanism within the `php-memcache' module is a
critical part of the interface as it controls the main interface to the
`memcached' instances and how the different instances are selected
through the hashing mechanism.

To create a simple connection to two `memcached' instances:

     <?php

     $cache = new Memcache;
     $cache->addServer('192.168.0.100',11211);
     $cache->addServer('192.168.0.101',11211);
     ?>

In this scenario the instance connection is not explicitly opened, but
only opened when you try to store or retrieve a value. You can enable
persistent connections to `memcached' instances by setting the
`$persistent' argument to true. This is the default setting, and causes
the connections to remain open.

To help control the distribution of keys to different instances, use
the global `memcache.hash_strategy' setting. This sets the hashing
mechanism used to select. You can also add another weight to each
server, which effectively increases the number of times the instance
entry appears in the instance list, therefore increasing the likelihood
of the instance being chosen over other instances. To set the weight,
set the value of the `$weight' argument to more than one.

The functions for setting and retrieving information are identical to
the generic functional interface offered by `memcached', as shown in
this table.

PECL `memcache' Function             Equivalent to
`get()'                              Generic `get()'
`set()'                              Generic `set()'
`add()'                              Generic `add()'
`replace()'                          Generic `replace()'
`delete()'                           Generic `delete()'
`increment()'                        Generic `incr()'
`decrement()'                        Generic `decr()'

A full example of the PECL `memcache' interface is provided below. The
code loads film data from the Sakila database when the user provides a
film name. The data stored into the `memcached' instance is recorded as
a `mysqli' result row, and the API automatically serializes the
information for you.

     <?php

     $memc = new Memcache;
     $memc->addServer('localhost','11211');
     ?>

     <html xmlns="http://www.w3.org/1999/xhtml" xml:lang="en" lang="en">
     <head>
      <meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
      <title>Simple Memcache Lookup</title>
     </head>
     <body>
     <form method="post">
       <p><b>Film</b>: <input type="text" size="20" name="film"></p>
     <input type="submit">
     </form>
     <hr/>

     <?php

       echo "Loading data...\n";

     $value = $memc->get($_REQUEST['film']);

     if ($value)
       {
         printf("<p>Film data for %s loaded from memcache</p>",$value['title']);

         foreach (array_keys($value) as $key)
           {
     	printf("<p><b>%s</b>: %s</p>",$key, $value[$key]);
           }
       }
      else
        {
          $con = new mysqli('localhost','sakila','password','sakila') or
            die ("<h1>Database problem</h1>" . mysqli_connect_error());

          $result = $con->query(sprintf('select * from film where title ="%s"',$_REQUEST['film']));

          $row = $result->fetch_array(MYSQLI_ASSOC);

          $memc->set($row['title'],$row);

          printf("<p>Loaded %s from MySQL</p>",$row['title']);
        }

     ?>

With PHP, the connections to the `memcached' instances are kept open as
long as the PHP and associated Apache instance remain running. When
adding a removing servers from the list in a running instance (for
example, when starting another script that mentions additional
servers), the connections are shared, but the script only selects among
the instances explicitly configured within the script.

To ensure that changes to the server list within a script do not cause
problems, make sure to use the consistent hashing mechanism.


File: manual.info,  Node: ha-memcached-interfaces-ruby,  Next: ha-memcached-interfaces-java,  Prev: ha-memcached-interfaces-php,  Up: ha-memcached-interfaces

15.6.3.11 Using MySQL and `memcached' with Ruby
...............................................

There are a number of different modules for interfacing to `memcached'
within Ruby. The `Ruby-MemCache' client library provides a native
interface to `memcached' that does not require any external libraries,
such as `libmemcached'. You can obtain the installer package from
`http://www.deveiate.org/projects/RMemCache'.

To install, extract the package and then run `install.rb':

     shell> install.rb

If you have RubyGems, you can install the `Ruby-MemCache' gem:

     shell> gem install Ruby-MemCache
     Bulk updating Gem source index for: http://gems.rubyforge.org
     Install required dependency io-reactor? [Yn]  y
     Successfully installed Ruby-MemCache-0.0.1
     Successfully installed io-reactor-0.05
     Installing ri documentation for io-reactor-0.05...
     Installing RDoc documentation for io-reactor-0.05...

To use a `memcached' instance from within Ruby, create a new instance
of the `MemCache' object.

     require 'memcache'
     memc = MemCache::new '192.168.0.100:11211'

You can add a weight to each server to increase the likelihood of the
server being selected during hashing by appending the weight count to
the server host name/port string:

     require 'memcache'
     memc = MemCache::new '192.168.0.100:11211:3'

To add servers to an existing list, you can append them directly to the
`MemCache' object:

     memc += ["192.168.0.101:11211"]

To set data into the cache, you can just assign a value to a key within
the new cache object, which works just like a standard Ruby hash object:

     memc["key"] = "value"

Or to retrieve the value:

     print memc["key"]

For more explicit actions, you can use the method interface, which
mimics the main `memcached' API functions, as summarized in the
following table.

Ruby `MemCache' Method               Equivalent to
`get()'                              Generic `get()'
`get_hash(keys)'                     Get the values of multiple `keys',
                                     returning the information as a hash
                                     of the keys and their values.
`set()'                              Generic `set()'
`set_many(pairs)'                    Set the values of the keys and
                                     values in the hash `pairs'.
`add()'                              Generic `add()'
`replace()'                          Generic `replace()'
`delete()'                           Generic `delete()'
`incr()'                             Generic `incr()'
`decr()'                             Generic `decr()'


File: manual.info,  Node: ha-memcached-interfaces-java,  Next: ha-memcached-interfaces-mysqludf,  Prev: ha-memcached-interfaces-ruby,  Up: ha-memcached-interfaces

15.6.3.12 Using MySQL and `memcached' with Java
...............................................

The `com.danga.MemCached' class within Java provides a native interface
to `memcached' instances. You can obtain the client from
`http://whalin.com/memcached/'. The Java class uses hashes that are
compatible with `libmemcached', so you can mix and match Java and
`libmemcached' applications accessing the same `memcached' instances.
The serialization between Java and other interfaces are not compatible.
If this is a problem, use JSON or a similar nonbinary serialization
format.

On most systems you can download the package and use the `jar' directly.

To use the `com.danga.MemCached' interface, you create a
`MemCachedClient' instance and then configure the list of servers by
configuring the `SockIOPool'. Through the pool specification you set up
the server list, weighting, and the connection parameters to optimized
the connections between your client and the `memcached' instances that
you configure.

Generally you can configure the `memcached' interface once within a
single class and then use this interface throughout the rest of your
application.

For example, to create a basic interface, first configure the
`MemCachedClient' and base `SockIOPool' settings:

     public class MyClass {

         protected static MemCachedClient mcc = new MemCachedClient();

         static {

             String[] servers =
                 {
                     "localhost:11211",
                 };

             Integer[] weights = { 1 };

             SockIOPool pool = SockIOPool.getInstance();

             pool.setServers( servers );
             pool.setWeights( weights );

In the above sample, the list of servers is configured by creating an
array of the `memcached' instances to use. You can then configure
individual weights for each server.

The remainder of the properties for the connection are optional, but
you can set the connection numbers (initial connections, minimum
connections, maximum connections, and the idle timeout) by setting the
pool parameters:

     pool.setInitConn( 5 );
     pool.setMinConn( 5 );
     pool.setMaxConn( 250 );
     pool.setMaxIdle( 1000 * 60 * 60 * 6

Once the parameters have been configured, initialize the connection
pool:

     pool.initialize();

The pool, and the connection to your `memcached' instances should now
be ready to use.

To set the hashing algorithm used to select the server used when
storing a given key you can use `pool.setHashingAlg()':

     pool.setHashingAlg( SockIOPool.NEW_COMPAT_HASH );

Valid values are `NEW_COMPAT_HASH', `OLD_COMPAT_HASH' and `NATIVE_HASH'
are also basic modula hashing algorithms. For a consistent hashing
algorithm, use `CONSISTENT_HASH'. These constants are equivalent to the
corresponding hash settings within `libmemcached'.

Java `com.danga.MemCached' Method    Equivalent to
`get()'                              Generic `get()'
`getMulti(keys)'                     Get the values of multiple `keys',
                                     returning the information as Hash
                                     map using `java.lang.String' for
                                     the keys and `java.lang.Object' for
                                     the corresponding values.
`set()'                              Generic `set()'
`add()'                              Generic `add()'
`replace()'                          Generic `replace()'
`delete()'                           Generic `delete()'
`incr()'                             Generic `incr()'
`decr()'                             Generic `decr()'


File: manual.info,  Node: ha-memcached-interfaces-mysqludf,  Next: ha-memcached-interfaces-protocol,  Prev: ha-memcached-interfaces-java,  Up: ha-memcached-interfaces

15.6.3.13 Using the MySQL `memcached' UDFs
..........................................

The `memcached' MySQL User Defined Functions (UDFs) enable you to set
and retrieve objects from within MySQL 5.0 or greater.

To install the MySQL `memcached' UDFs, download the UDF package from
`http://libmemcached.org/'.  Unpack the package and run `configure' to
configure the build process. When running `configure', use the
`--with-mysql' option and specify the location of the *Note
`mysql_config': mysql-config. command.

     shell> tar zxf memcached_functions_mysql-0.5.tar.gz
     shell> cd memcached_functions_mysql-0.5
     shell> ./configure --with-mysql-config=/usr/local/mysql/bin/mysql_config

Now build and install the functions:

     shell> make
     shell> make install

Copy the MySQL `memcached' UDFs into your MySQL plugins directory:

     shell> cp /usr/local/lib/libmemcached_functions_mysql* /usr/local/mysql/lib/mysql/plugins/

The plugin directory is given by the value of the `plugin_dir' system
variable. For more information, see *Note udf-compiling::.

Once installed, you must initialize the function within MySQL using
`CREATE' and specifying the return value and library. For example, to
add the `memc_get()' function:

     mysql> CREATE FUNCTION memc_get RETURNS STRING SONAME "libmemcached_functions_mysql.so";

Repeat this process for each function to provide access to within
MySQL. Once you have created the association, the information is
retained, even over restarts of the MySQL server.  You can simplify the
process by using the SQL script provided in the `memcached' UDFs
package:

     shell> mysql <sql/install_functions.sql

Alternatively, if you have Perl installed, then you can use the
supplied Perl script, which checks for the existence of each function
and creates the function/library association if it is not already
defined:

     shell> utils/install.pl --silent

The `--silent' option installs everything automatically. Without this
option, the script asks whether to install each of the available
functions.

The interface remains consistent with the other APIs and interfaces. To
set up a list of servers, use the `memc_servers_set()' function, which
accepts a single string containing and comma-separated list of servers:

     mysql> SELECT memc_servers_set('192.168.0.1:11211,192.168.0.2:11211');

*Note*:

The list of servers used by the `memcached' UDFs is not persistent over
restarts of the MySQL server. If the MySQL server fails, then you must
re-set the list of `memcached' servers.

To set a value, use `memc_set':

     mysql> SELECT memc_set('myid', 'myvalue');

To retrieve a stored value:

     mysql> SELECT memc_get('myid');

The list of functions supported by the UDFs, in relation to the
standard protocol functions, is shown in the following table.

MySQL `memcached' UDF Function       Equivalent to
`memc_get()'                         Generic `get()'
`memc_get_by_key(master_key, key,    Like the generic `get()', but uses
value)'                              the supplied master key to select
                                     the server to use.
`memc_set()'                         Generic `set()'
`memc_set_by_key(master_key, key,    Like the generic `set()', but uses
value)'                              the supplied master key to select
                                     the server to use.
`memc_add()'                         Generic `add()'
`memc_add_by_key(master_key, key,    Like the generic `add()', but uses
value)'                              the supplied master key to select
                                     the server to use.
`memc_replace()'                     Generic `replace()'
`memc_replace_by_key(master_key,     Like the generic `replace()', but
key, value)'                         uses the supplied master key to
                                     select the server to use.
`memc_prepend(key, value)'           Prepend the specified `value' to
                                     the current value of the specified
                                     `key'.
`memc_prepend_by_key(master_key,     Prepend the specified `value' to
key, value)'                         the current value of the specified
                                     `key', but uses the supplied master
                                     key to select the server to use.
`memc_append(key, value)'            Append the specified `value' to the
                                     current value of the specified
                                     `key'.
`memc_append_by_key(master_key,      Append the specified `value' to the
key, value)'                         current value of the specified
                                     `key', but uses the supplied master
                                     key to select the server to use.
`memc_delete()'                      Generic `delete()'
`memc_delete_by_key(master_key,      Like the generic `delete()', but
key, value)'                         uses the supplied master key to
                                     select the server to use.
`memc_increment()'                   Generic `incr()'
`memc_decrement()'                   Generic `decr()'

The respective `*_by_key()' functions are useful to store a specific
value into a specific `memcached' server, possibly based on a
differently calculated or constructed key.

The `memcached' UDFs include some additional functions:

   * `memc_server_count()'

     Returns a count of the number of servers in the list of registered
     servers.

   * `memc_servers_set_behavior(behavior_type, value)',
     `memc_set_behavior(behavior_type, value)'

     Set behaviors for the list of servers. These behaviors are
     identical to those provided by the `libmemcached' library. For more
     information on `libmemcached' behaviors, see *Note
     ha-memcached-interfaces-libmemcached::.

     You can use the behavior name as the `behavior_type':

          mysql> SELECT memc_servers_behavior_set("MEMCACHED_BEHAVIOR_KETAMA",1);

   * `memc_servers_behavior_get(behavior_type)',
     `memc_get_behavior(behavior_type, value)'

     Returns the value for a given behavior.

   * `memc_list_behaviors()'

     Returns a list of the known behaviors.

   * `memc_list_hash_types()'

     Returns a list of the supported key-hashing algorithms.

   * `memc_list_distribution_types()'

     Returns a list of the supported distribution types to be used when
     selecting a server to use when storing a particular key.

   * `memc_libmemcached_version()'

     Returns the version of the `libmemcached' library.

   * `memc_stats()'

     Returns the general statistics information from the server.


File: manual.info,  Node: ha-memcached-interfaces-protocol,  Prev: ha-memcached-interfaces-mysqludf,  Up: ha-memcached-interfaces

15.6.3.14 `memcached' Protocol
..............................

* Menu:

* ha-memcached-interfaces-protocol-tcp::  Using the TCP text protocol

Communicating with a `memcached' server can be achieved through either
the TCP or UDP protocols. When using the TCP protocol you can use a
simple text based interface for the exchange of information.


File: manual.info,  Node: ha-memcached-interfaces-protocol-tcp,  Prev: ha-memcached-interfaces-protocol,  Up: ha-memcached-interfaces-protocol

15.6.3.15 Using the TCP text protocol
.....................................

When communicating with `memcached' you can connect to the server using
the port configured for the server. You can open a connection with the
server without requiring authorization or login. As soon as you have
connected, you can start to send commands to the server. When you have
finished, you can terminate the connection without sending any specific
disconnection command. Clients are encouraged to keep their connections
open to decrease latency and improve performance.

Data is sent to the `memcached' server in two forms:

   * Text lines, which are used to send commands to the server, and
     receive responses from the server.

   * Unstructured data, which is used to receive or send the value
     information for a given key. Data is returned to the client in
     exactly the format it was provided.

Both text lines (commands and responses) and unstructured data are
always terminated with the string `\r\n'.  Because the data being
stored may contain this sequence, the length of the data (returned by
the client before the unstructured data is transmitted should be used
to determine the end of the data.

Commands to the server are structured according to their operation:

   * *Storage commands*: `set', `add', `replace', `append', `prepend',
     `cas'

     Storage commands to the server take the form:

          command key [flags] [exptime] length [noreply]

     Or when using compare and swap (cas):

          cas key [flags] [exptime] length [casunique] [noreply]

     Where:

        * `command': The command name.

             * `set': Store value against key

             * `add': Store this value against key if the key does not
               already exist

             * `replace': Store this value against key if the key
               already exists

             * `append': Append the supplied value to the end of the
               value for the specified key. The `flags' and `exptime'
               arguments should not be used.

             * `prepend': Append value currently in the cache to the
               end of the supplied value for the specified key. The
               `flags' and `exptime' arguments should not be used.

             * `cas': Set the specified key to the supplied value, only
               if the supplied `casunique' matches. This is effectively
               the equivalent of change the information if nobody has
               updated it since I last fetched it.

        * `key': The key. All data is stored using a the specific key.
          The key cannot contain control characters or whitespace, and
          can be up to 250 characters in size.

        * `flags': The flags for the operation (as an integer). Flags
          in `memcached' are transparent. The `memcached' server
          ignores the contents of the flags. They can be used by the
          client to indicate any type of information. In `memcached'
          1.2.0 and lower the value is a 16-bit integer value. In
          `memcached' 1.2.1 and higher the value is a 32-bit integer.

        * `exptime': The expiry time, or zero for no expiry.

        * `length': The length of the supplied value block in bytes,
          excluding the terminating `\r\n' characters.

        * `casunique': A unique 64-bit value of an existing entry. This
          is used to compare against the existing value. Use the value
          returned by the `gets' command when issuing `cas' updates.

        * `noreply': Tells the server not to reply to the command.

     For example, to store the value `abcdef' into the key `xyzkey',
     you would use:

          set xyzkey 0 0 6\r\nabcdef\r\n

     The return value from the server is one line, specifying the
     status or error information. For more information, see *Note
     ha-memcached-interfaces-protocol-responses::.

   * *Retrieval commands*: `get', `gets'

     Retrieval commands take the form:

          get key1 [key2 .... keyn]
          gets key1 [key2 ... keyn]

     You can supply multiple keys to the commands, with each requested
     key separated by whitespace.

     The server responds with an information line of the form:

          VALUE key flags bytes [casunique]

     Where:

        * `key': The key name.

        * `flags': The value of the flag integer supplied to the
          `memcached' server when the value was stored.

        * `bytes': The size (excluding the terminating `\r\n' character
          sequence) of the stored value.

        * `casunique': The unique 64-bit integer that identifies the
          item.

     The information line is immediately followed by the value data
     block. For example:

          get xyzkey\r\n
          VALUE xyzkey 0 6\r\n
          abcdef\r\n

     If you have requested multiple keys, an information line and data
     block is returned for each key found. If a requested key does not
     exist in the cache, no information is returned.

   * *Delete commands*: `delete'

     Deletion commands take the form:

          delete key [time] [noreply]

     Where:

        * `key': The key name.

        * `time': The time in seconds (or a specific Unix time) for
          which the client wishes the server to refuse `add' or
          `replace' commands on this key. All `add', `replace', `get',
          and `gets' commands fail during this period.  `set'
          operations succeed. After this period, the key is deleted
          permanently and all commands are accepted.

          If not supplied, the value is assumed to be zero (delete
          immediately).

        * `noreply': Tells the server not to reply to the command.

     Responses to the command are either `DELETED' to indicate that the
     key was successfully removed, or `NOT_FOUND' to indicate that the
     specified key could not be found.

   * *Increment/Decrement*: `incr', `decr'

     The increment and decrement commands change the value of a key
     within the server without performing a separate get/set sequence.
     The operations assume that the currently stored value is a 64-bit
     integer. If the stored value is not a 64-bit integer, then the
     value is assumed to be zero before the increment or decrement
     operation is applied.

     Increment and decrement commands take the form:

          incr key value [noreply]
          decr key value [noreply]

     Where:

        * `key': The key name.

        * `value': An integer to be used as the increment or decrement
          value.

        * `noreply': Tells the server not to reply to the command.

     The response is:

        * `NOT_FOUND': The specified key could not be located.

        * `value': The new value of the specified key.

     Values are assumed to be unsigned. For `decr' operations the value
     is never decremented below 0. For `incr' operations, the value
     wraps around the 64-bit maximum.

   * *Statistics commands*: `stats'

     The `stats' command provides detailed statistical information
     about the current status of the `memcached' instance and the data
     it is storing.

     Statistics commands take the form:

          STAT [name] [value]

     Where:

        * `name': The optional name of the statistics to return. If not
          specified, the general statistics are returned.

        * `value': A specific value to be used when performing certain
          statistics operations.

     The return value is a list of statistics data, formatted as
     follows:

          STAT name value

     The statistics are terminated with a single line, `END'.

     For more information, see *Note ha-memcached-stats::.

For reference, a list of the different commands supported and their
formats is provided below.

*`memcached' Command Reference*

Command            Command Formats
`set'              `set key flags exptime length', `set key flags
                   exptime length noreply'
`add'              `add key flags exptime length', `add key flags
                   exptime length noreply'
`replace'          `replace key flags exptime length', `replace key
                   flags exptime length noreply'
`append'           `append key length', `append key length noreply'
`prepend'          `prepend key length', `prepend key length noreply'
`cas'              `cas key flags exptime length casunique', `cas key
                   flags exptime length casunique noreply'
`get'              `get key1 [key2 ... keyn]'
`gets'             `'
`delete'           `delete key', `delete key noreply', `delete key
                   expiry', `delete key expiry noreply'
`incr'             `incr key', `incr key noreply', `incr key value',
                   `incr key value noreply'
`decr'             `decr key', `decr key noreply', `decr key value',
                   `decr key value noreply'
`stat'             `stat', `stat name', `stat name value'

When sending a command to the server, the response from the server is
one of the settings in the following table. All response values from
the server are terminated by `\r\n':

*`memcached' Protocol Responses*

String             Description
`STORED'           Value has successfully been stored.
`NOT_STORED'       The value was not stored, but not because of an
                   error. For commands where you are adding a or
                   updating a value if it exists (such as `add' and
                   `replace'), or where the item has already been set to
                   be deleted.
`EXISTS'           When using a `cas' command, the item you are trying to
                   store already exists and has been modified since you
                   last checked it.
`NOT_FOUND'        The item you are trying to store, update or delete
                   does not exist or has already been deleted.
`ERROR'            You submitted a nonexistent command name.
`CLIENT_ERROR      There was an error in the input line, the detail is
errorstring'       contained in `errorstring'.
`SERVER_ERROR      There was an error in the server that prevents it
errorstring'       from returning the information. In extreme
                   conditions, the server may disconnect the client
                   after this error occurs.
`VALUE keys flags  The requested key has been found, and the stored
length'            `key', `flags' and data block are returned, of the
                   specified `length'.
`DELETED'          The requested key was deleted from the server.
`STAT name value'  A line of statistics data.
`END'              The end of the statistics data.


File: manual.info,  Node: ha-memcached-stats,  Next: ha-memcached-faq,  Prev: ha-memcached-interfaces,  Up: ha-memcached

15.6.4 Getting `memcached' Statistics
-------------------------------------

* Menu:

* ha-memcached-stats-general::   `memcached' General Statistics
* ha-memcached-stats-slabs::     `memcached' Slabs Statistics
* ha-memcached-stats-items::     `memcached' Item Statistics
* ha-memcached-stats-sizes::     `memcached' Size Statistics
* ha-memcached-stats-detail::    `memcached' Detail Statistics
* ha-memcached-stats-memcached-tool::  Using `memcached-tool'

The `memcached' system has a built in statistics system that collects
information about the data being stored into the cache, cache hit
ratios, and detailed information on the memory usage and distribution
of information through the slab allocation used to store individual
items. Statistics are provided at both a basic level that provide the
core statistics, and more specific statistics for specific areas of the
`memcached' server.

This information can prove be very useful to ensure that you are
getting the correct level of cache and memory usage, and that your slab
allocation and configuration properties are set at an optimal level.

The stats interface is available through the standard `memcached'
protocol, so the reports can be accessed by using `telnet' to connect
to the `memcached'. The supplied `memcached-tool' includes support for
obtaining the *Note ha-memcached-stats-slabs:: and *Note
ha-memcached-stats-general:: information. For more information, see
*Note ha-memcached-stats-memcached-tool::.

Alternatively, most of the language API interfaces provide a function
for obtaining the statistics from the server.

For example, to get the basic stats using `telnet':

     shell> telnet localhost 11211
     Trying ::1...
     Connected to localhost.
     Escape character is '^]'.
     stats
     STAT pid 23599
     STAT uptime 675
     STAT time 1211439587
     STAT version 1.2.5
     STAT pointer_size 32
     STAT rusage_user 1.404992
     STAT rusage_system 4.694685
     STAT curr_items 32
     STAT total_items 56361
     STAT bytes 2642
     STAT curr_connections 53
     STAT total_connections 438
     STAT connection_structures 55
     STAT cmd_get 113482
     STAT cmd_set 80519
     STAT get_hits 78926
     STAT get_misses 34556
     STAT evictions 0
     STAT bytes_read 6379783
     STAT bytes_written 4860179
     STAT limit_maxbytes 67108864
     STAT threads 1
     END

When using Perl and the `Cache::Memcached' module, the `stats()'
function returns information about all the servers currently configured
in the connection object, and total statistics for all the `memcached'
servers as a whole.

For example, the following Perl script obtains the stats and dumps the
hash reference that is returned:

     use Cache::Memcached;
     use Data::Dumper;

     my $memc = new Cache::Memcached;
     $memc->set_servers(\@ARGV);

     print Dumper($memc->stats());

When executed on the same `memcached' as used in the `Telnet' example
above we get a hash reference with the host by host and total
statistics:

     $VAR1 = {
         'hosts' => {
                'localhost:11211' => {
                           'misc' => {
                                 'bytes' => '2421',
                                 'curr_connections' => '3',
                                 'connection_structures' => '56',
                                 'pointer_size' => '32',
                                 'time' => '1211440166',
                                 'total_items' => '410956',
                                 'cmd_set' => '588167',
                                 'bytes_written' => '35715151',
                                 'evictions' => '0',
                                 'curr_items' => '31',
                                 'pid' => '23599',
                                 'limit_maxbytes' => '67108864',
                                 'uptime' => '1254',
                                 'rusage_user' => '9.857805',
                                 'cmd_get' => '838451',
                                 'rusage_system' => '34.096988',
                                 'version' => '1.2.5',
                                 'get_hits' => '581511',
                                 'bytes_read' => '46665716',
                                 'threads' => '1',
                                 'total_connections' => '3104',
                                 'get_misses' => '256940'
                               },
                           'sizes' => {
                                  '128' => '16',
                                  '64' => '15'
                                }
                         }
              },
         'self' => {},
         'total' => {
                'cmd_get' => 838451,
                'bytes' => 2421,
                'get_hits' => 581511,
                'connection_structures' => 56,
                'bytes_read' => 46665716,
                'total_items' => 410956,
                'total_connections' => 3104,
                'cmd_set' => 588167,
                'bytes_written' => 35715151,
                'curr_items' => 31,
                'get_misses' => 256940
              }
             };

The statistics are divided up into a number of distinct sections, and
then can be requested by adding the type to the `stats' command. Each
statistics output is covered in more detail in the following sections.

   * General statistics, see *Note ha-memcached-stats-general::.

   * Slab statistics (`slabs'), see *Note ha-memcached-stats-slabs::.

   * Item statistics (`items'), see *Note ha-memcached-stats-items::.

   * Size statistics (`sizes'), see *Note ha-memcached-stats-sizes::.

   * Detailed status (`detail'), see *Note ha-memcached-stats-detail::.


File: manual.info,  Node: ha-memcached-stats-general,  Next: ha-memcached-stats-slabs,  Prev: ha-memcached-stats,  Up: ha-memcached-stats

15.6.4.1 `memcached' General Statistics
.......................................

The output of the general statistics provides an overview of the
performance and use of the `memcached' instance. The statistics
returned by the command and their meaning is shown in the following
table.

The following terms are used to define the value type for each
statistics value:

   * `32u': 32-bit unsigned integer

   * `64u': 64-bit unsigned integer

   * `32u32u': Two 32-bit unsigned integers separated by a colon

   * `String': Character string

Statistic      Data type   Description                              Version
pid            32u         Process ID of the `memcached' instance.  
uptime         32u         Uptime (in seconds) for this             
                           `memcached' instance.                    
time           32u         Current time (as epoch).                 
version        string      Version string of this instance.         
pointer_size   string      Size of pointers for this host           
                           specified in bits (32 or 64).            
rusage_user    32u:32u     Total user time for this instance        
                           (seconds:microseconds).                  
rusage_system  32u:32u     Total system time for this instance      
                           (seconds:microseconds).                  
curr_items     32u         Current number of items stored by this   
                           instance.                                
total_items    32u         Total number of items stored during the  
                           life of this instance.                   
bytes          64u         Current number of bytes used by this     
                           server to store items.                   
curr_connections32u         Current number of open connections.      
total_connections32u         Total number of connections opened       
                           since the server started running.        
connection_structures32u         Number of connection structures          
                           allocated by the server.                 
cmd_get        64u         Total number of retrieval requests       
                           (`get' operations).                      
cmd_set        64u         Total number of storage requests (`set'  
                           operations).                             
get_hits       64u         Number of keys that have been requested  
                           and found present.                       
get_misses     64u         Number of items that have been           
                           requested and not found.                 
delete_hits    64u         Number of keys that have been deleted    1.3.x
                           and found present.                       
delete_misses  64u         Number of items that have been delete    1.3.x
                           and not found.                           
incr_hits      64u         Number of keys that have been            1.3.x
                           incremented and found present.           
incr_misses    64u         Number of items that have been           1.3.x
                           incremented and not found.               
decr_hits      64u         Number of keys that have been            1.3.x
                           decremented and found present.           
decr_misses    64u         Number of items that have been           1.3.x
                           decremented and not found.               
cas_hits       64u         Number of keys that have been compared   1.3.x
                           and swapped and found present.           
cas_misses     64u         Number of items that have been compared  1.3.x
                           and swapped and not found.               
cas_badvalue   64u         Number of keys that have been compared   1.3.x
                           and swapped, but the comparison          
                           (original) value did not match the       
                           supplied value.                          
evictions      64u         Number of valid items removed from       
                           cache to free memory for new items.      
bytes_read     64u         Total number of bytes read by this       
                           server from network.                     
bytes_written  64u         Total number of bytes sent by this       
                           server to network.                       
limit_maxbytes 32u         Number of bytes this server is           
                           permitted to use for storage.            
threads        32u         Number of worker threads requested.      
conn_yields    64u         Number of yields for connections         1.4.0
                           (related to the `-R' option).            

The most useful statistics from those given here are the number of
cache hits, misses, and evictions.

A large number of `get_misses' may just be an indication that the cache
is still being populated with information. The number should, over
time, decrease in comparison to the number of cache `get_hits'.  If,
however, you have a large number of cache misses compared to cache hits
after an extended period of execution, it may be an indication that the
size of the cache is too small and you either need to increase the
total memory size, or increase the number of the `memcached' instances
to improve the hit ratio.

A large number of `evictions' from the cache, particularly in
comparison to the number of items stored is a sign that your cache is
too small to hold the amount of information that you regularly want to
keep cached. Instead of items being retained in the cache, items are
being evicted to make way for new items keeping the turnover of items
in the cache high, reducing the efficiency of the cache.


File: manual.info,  Node: ha-memcached-stats-slabs,  Next: ha-memcached-stats-items,  Prev: ha-memcached-stats-general,  Up: ha-memcached-stats

15.6.4.2 `memcached' Slabs Statistics
.....................................

To get the `slabs' statistics, use the `stats slabs' command, or the
API equivalent.

The slab statistics provide you with information about the slabs that
have created and allocated for storing information within the cache.
You get information both on each individual slab-class and total
statistics for the whole slab.

     STAT 1:chunk_size 104
     STAT 1:chunks_per_page 10082
     STAT 1:total_pages 1
     STAT 1:total_chunks 10082
     STAT 1:used_chunks 10081
     STAT 1:free_chunks 1
     STAT 1:free_chunks_end 10079
     STAT 9:chunk_size 696
     STAT 9:chunks_per_page 1506
     STAT 9:total_pages 63
     STAT 9:total_chunks 94878
     STAT 9:used_chunks 94878
     STAT 9:free_chunks 0
     STAT 9:free_chunks_end 0
     STAT active_slabs 2
     STAT total_malloced 67083616
     END

Individual stats for each slab class are prefixed with the slab ID. A
unique ID is given to each allocated slab from the smallest size up to
the largest. The prefix number indicates the slab class number in
relation to the calculated chunk from the specified growth factor.
Hence in the example, 1 is the first chunk size and 9 is the 9th chunk
allocated size.

The different parameters returned for each chunk size and the totals
are shown in the following table.

Statistic          Description                              Version
chunk_size         Space allocated to each chunk within     
                   this slab class.                         
chunks_per_page    Number of chunks within a single page    
                   for this slab class.                     
total_pages        Number of pages allocated to this slab   
                   class.                                   
total_chunks       Number of chunks allocated to the slab   
                   class.                                   
used_chunks        Number of chunks allocated to an item..  
free_chunks        Number of chunks not yet allocated to    
                   items.                                   
free_chunks_end    Number of free chunks at the end of the  
                   last allocated page.                     
get_hits           Number of get hits to this chunk         1.3.x
cmd_set            Number of set commands on this chunk     1.3.x
delete_hits        Number of delete hits to this chunk      1.3.x
incr_hits          Number of increment hits to this chunk   1.3.x
decr_hits          Number of decrement hits to this chunk   1.3.x
cas_hits           Number of CAS hits to this chunk         1.3.x
cas_badval         Number of CAS hits on this chunk where   1.3.x
                   the existing value did not match         
mem_requested      The true amount of memory of memory      1.4.1
                   requested within this chunk              

The following additional statistics cover the information for the
entire server, rather than on a chunk by chunk basis:

Statistic          Description                              Version
active_slabs       Total number of slab classes allocated.  
total_malloced     Total amount of memory allocated to      
                   slab pages.                              

The key values in the slab statistics are the `chunk_size', and the
corresponding `total_chunks' and `used_chunks' parameters. These given
an indication of the size usage of the chunks within the system.
Remember that one key/value pair is placed into a chunk of a suitable
size.

From these stats, you can get an idea of your size and chunk allocation
and distribution. If you store many items with a number of largely
different sizes, consider adjusting the chunk size growth factor to
increase in larger steps to prevent chunk and memory wastage. A good
indication of a bad growth factor is a high number of different slab
classes, but with relatively few chunks actually in use within each
slab. Increasing the growth factor creates fewer slab classes and
therefore makes better use of the allocated pages.


File: manual.info,  Node: ha-memcached-stats-items,  Next: ha-memcached-stats-sizes,  Prev: ha-memcached-stats-slabs,  Up: ha-memcached-stats

15.6.4.3 `memcached' Item Statistics
....................................

To get the `items' statistics, use the `stats items' command, or the
API equivalent.

The `items' statistics give information about the individual items
allocated within a given slab class.

     STAT items:2:number 1
     STAT items:2:age 452
     STAT items:2:evicted 0
     STAT items:2:evicted_nonzero 0
     STAT items:2:evicted_time 2
     STAT items:2:outofmemory 0
     STAT items:2:tailrepairs 0
     ...
     STAT items:27:number 1
     STAT items:27:age 452
     STAT items:27:evicted 0
     STAT items:27:evicted_nonzero 0
     STAT items:27:evicted_time 2
     STAT items:27:outofmemory 0
     STAT items:27:tailrepairs 0

The prefix number against each statistics relates to the corresponding
chunk size, as returned by the `stats slabs' statistics. The result is
a display of the number of items stored within each chunk within each
slab size, and specific statistics about their age, eviction counts, and
out of memory counts. A summary of the statistics is given in the
following table.

Statistic          Description                                     
`number'           The number of items currently stored in this    
                   slab class.                                     
`age'              The age of the oldest item within the slab      
                   class, in seconds.                              
`evicted'          The number of items evicted to make way for     
                   new entries.                                    
`evicted_time'     The time of the last evicted entry              
`evicted_nonzero'  The time of the last evicted non-zero entry     1.4.0
`outofmemory'      The number of items for this slab class that    
                   have triggered an out of memory error (only     
                   value when the `-M' command line option is in   
                   effect).                                        
tailrepairs        Number of times the entries for a particular    
                   ID need repairing                               

Item level statistics can be used to determine how many items are
stored within a given slab and their freshness and recycle rate. You
can use this to help identify whether there are certain slab classes
that are triggering a much larger number of evictions that others.


File: manual.info,  Node: ha-memcached-stats-sizes,  Next: ha-memcached-stats-detail,  Prev: ha-memcached-stats-items,  Up: ha-memcached-stats

15.6.4.4 `memcached' Size Statistics
....................................

To get size statistics, use the `stats sizes' command, or the API
equivalent.

The size statistics provide information about the sizes and number of
items of each size within the cache. The information is returned as two
columns, the first column is the size of the item (rounded up to the
nearest 32 byte boundary), and the second column is the count of the
number of items of that size within the cache:

     96 35
     128 38
     160 807
     192 804
     224 410
     256 222
     288 83
     320 39
     352 53
     384 33
     416 64
     448 51
     480 30
     512 54
     544 39
     576 10065

*Caution*:

Running this statistic locks up your cache as each item is read from
the cache and its size calculated. On a large cache, this may take some
time and prevent any set or get operations until the process completes.

The item size statistics are useful only to determine the sizes of the
objects you are storing. Since the actual memory allocation is relevant
only in terms of the chunk size and page size, the information is only
useful during a careful debugging or diagnostic session.


File: manual.info,  Node: ha-memcached-stats-detail,  Next: ha-memcached-stats-memcached-tool,  Prev: ha-memcached-stats-sizes,  Up: ha-memcached-stats

15.6.4.5 `memcached' Detail Statistics
......................................

For `memcached' 1.3.x and higher, you can enable and obtain detailed
statistics about the get, set, and del operations on theindividual keys
stored in the cache, and determine whether the attempts hit (found) a
particular key.  These operations are only recorded while the detailed
stats analysis is turned on.

To enable detailed statistics, you must send the `stats detail on'
command to the `memcached' server:

     $ telnet localhost 11211
     Trying 127.0.0.1...
     Connected to tiger.
     Escape character is '^]'.stats detail on
     OK

Individual statistics are recorded for every `get', `set' and `del'
operation on a key, including keys that are not currently stored in the
server. For example, if an attempt is made to obtain the value of key
`abckey' and it does not exist, the `get' operating on the specified
key are recorded while detailed statistics are in effect, even if the
key is not currently stored. The `hits', that is, the number of `get' or
`del' operations for a key that exists in the server are also counted.

To turn detailed statistics off, send the `stats detail off' command to
the `memcached' server:

     $ telnet localhost 11211
     Trying 127.0.0.1...
     Connected to tiger.
     Escape character is '^]'.stats detail on
     OK

To obtain the detailed statistics recorded during the process, send the
`stats detail dump' command to the `memcached' server:

     stats detail dump
     PREFIX hykkey get 0 hit 0 set 1 del 0
     PREFIX xyzkey get 0 hit 0 set 1 del 0
     PREFIX yukkey get 1 hit 0 set 0 del 0
     PREFIX abckey get 3 hit 3 set 1 del 0
     END

You can use the detailed statistics information to determine whether
your `memcached' clients are using a large number of keys that do not
exist in the server by comparing the `hit' and `get' or `del' counts.
Because the information is recorded by key, you can also determine
whether the failures or operations are clustered around specific keys.


File: manual.info,  Node: ha-memcached-stats-memcached-tool,  Prev: ha-memcached-stats-detail,  Up: ha-memcached-stats

15.6.4.6 Using `memcached-tool'
...............................

The `memcached-tool', located within the `scripts' directory within the
`memcached' source directory. The tool provides convenient access to
some reports and statistics from any `memcached' instance.

The basic format of the command is:

     shell> ./memcached-tool hostname:port [command]

The default output produces a list of the slab allocations and usage.
For example:

     shell> memcached-tool localhost:11211 display
       #  Item_Size  Max_age   Pages   Count   Full?  Evicted Evict_Time OOM
       1      80B        93s       1      20      no        0        0    0
       2     104B        93s       1      16      no        0        0    0
       3     136B      1335s       1      28      no        0        0    0
       4     176B      1335s       1      24      no        0        0    0
       5     224B      1335s       1      32      no        0        0    0
       6     280B      1335s       1      34      no        0        0    0
       7     352B      1335s       1      36      no        0        0    0
       8     440B      1335s       1      46      no        0        0    0
       9     552B      1335s       1      58      no        0        0    0
      10     696B      1335s       1      66      no        0        0    0
      11     872B      1335s       1      89      no        0        0    0
      12     1.1K      1335s       1     112      no        0        0    0
      13     1.3K      1335s       1     145      no        0        0    0
      14     1.7K      1335s       1     123      no        0        0    0
      15     2.1K      1335s       1     198      no        0        0    0
      16     2.6K      1335s       1     199      no        0        0    0
      17     3.3K      1335s       1     229      no        0        0    0
      18     4.1K      1335s       1     248     yes       36        2    0
      19     5.2K      1335s       2     328      no        0        0    0
      20     6.4K      1335s       2     316     yes      387        1    0
      21     8.1K      1335s       3     381     yes      492        1    0
      22    10.1K      1335s       3     303     yes      598        2    0
      23    12.6K      1335s       5     405     yes      605        1    0
      24    15.8K      1335s       6     384     yes      766        2    0
      25    19.7K      1335s       7     357     yes      908      170    0
      26    24.6K      1336s       7     287     yes     1012        1    0
      27    30.8K      1336s       7     231     yes     1193      169    0
      28    38.5K      1336s       4     104     yes     1323      169    0
      29    48.1K      1336s       1      21     yes     1287        1    0
      30    60.2K      1336s       1      17     yes     1093      169    0
      31    75.2K      1337s       1      13     yes      713      168    0
      32    94.0K      1337s       1      10     yes      278      168    0
      33   117.5K      1336s       1       3      no        0        0    0

This output is the same if you specify the `command' as `display':

     shell> memcached-tool localhost:11211 display
       #  Item_Size  Max_age   Pages   Count   Full?  Evicted Evict_Time OOM
       1      80B        93s       1      20      no        0        0    0
       2     104B        93s       1      16      no        0        0    0
     ...

The output shows a summarized version of the output from the `slabs'
statistics. The columns provided in the output are shown below:

   * `#': The slab number

   * `Item_Size': The size of the slab

   * `Max_age': The age of the oldest item in the slab

   * `Pages': The number of pages allocated to the slab

   * `Count': The number of items in this slab

   * `Full?': Whether the slab is fully populated

   * `Evicted': The number of objects evicted from this slab

   * `Evict_Time': The time (in seconds) since the last eviction

   * `OOM': The number of items that have triggered an out of memory
     error

You can also obtain a dump of the general statistics for the server
using the `stats' command:

     shell> memcached-tool localhost:11211 stats
     #localhost:11211   Field       Value
              accepting_conns           1
                        bytes         162
                   bytes_read         485
                bytes_written        6820
                   cas_badval           0
                     cas_hits           0
                   cas_misses           0
                    cmd_flush           0
                      cmd_get           4
                      cmd_set           2
                  conn_yields           0
        connection_structures          11
             curr_connections          10
                   curr_items           2
                    decr_hits           0
                  decr_misses           1
                  delete_hits           0
                delete_misses           0
                    evictions           0
                     get_hits           4
                   get_misses           0
                    incr_hits           0
                  incr_misses           2
               limit_maxbytes    67108864
          listen_disabled_num           0
                          pid       12981
                 pointer_size          32
                rusage_system    0.013911
                  rusage_user    0.011876
                      threads           4
                         time  1255518565
            total_connections          20
                  total_items           2
                       uptime         880
                      version       1.4.2

The `memcached-tool' provides


File: manual.info,  Node: ha-memcached-faq,  Prev: ha-memcached-stats,  Up: ha-memcached

15.6.5 `memcached' FAQ
----------------------

*Questions*
   * 15.6.5.1: Can MySQL actually trigger/store the changed data to
     memcached?

   * 15.6.5.2: Can memcached be run on a Windows environment?

   * 15.6.5.3: Does the `-L' flag automatically sense how much memory
     is being used by other memcached?

   * 15.6.5.4: What is the max size of an object you can store in
     memcache and is that configurable?

   * 15.6.5.5: Is it true `memcached' will be much more effective with
     db-read-intensive applications than with db-write-intensive
     applications?

   * 15.6.5.6: `memcached' is fast - is there any overhead in not using
     persistent connections? If persistent is always recommended, what
     are the downsides (for example, locking up)?

   * 15.6.5.7: How does an event such as a crash of one of the
     `memcached' servers handled by the `memcached' client?

   * 15.6.5.8: What's a recommended hardware config for a memcached
     server?  Linux or Windows?

   * 15.6.5.9: Doing a direct telnet to the memcached port, is that
     just for that one machine, or does it magically apply across all
     nodes?

   * 15.6.5.10: Is memcached more effective for video and audio as
     opposed to textual read/writes

   * 15.6.5.11: If you log a complex class (with methods that do
     calculation etc) will the get from Memcache re-create the class on
     the way out?

   * 15.6.5.12: If I have an object larger then a MB, do I have to
     manually split it or can I configure `memcached' to handle larger
     objects?

   * 15.6.5.13: Can `memcached' work with `ASPX'?

   * 15.6.5.14: Are there any, or are there any plans to introduce, a
     framework to hide the interaction of memcached from the
     application; that is, within hibernate?

   * 15.6.5.15: So the responsibility lies with the application to
     populate and get records from the database as opposed to being a
     transparent cache layer for the db?

   * 15.6.5.16: How does `memcached' compare to nCache?

   * 15.6.5.17: We are caching XML by serialising using saveXML(),
     because PHP cannot serialize DOM objects; Some of the XML is
     variable and is modified per-request. Do you recommend caching
     then using XPath, or is it better to rebuild the DOM from separate
     node-groups?

   * 15.6.5.18: How easy is it to introduce `memcached' to an existing
     enterprise application instead of inclusion at project design?

   * 15.6.5.19: Do the memcache UDFs work under 5.1?

   * 15.6.5.20: Is the data inside of `memcached' secure?

   * 15.6.5.21: Is `memcached' typically a better solution for
     improving speed than MySQL Cluster and\or MySQL Proxy?

   * 15.6.5.22: File socket support for `memcached' from the localhost
     use to the local memcached server?

   * 15.6.5.23: How expensive is it to establish a memcache connection?
     Should those connections be pooled?

   * 15.6.5.24: What are the advantages of using UDFs when the get/sets
     are manageable from within the client code rather than the db?

   * 15.6.5.25: How will the data will be handled when the `memcached'
     server is down?

   * 15.6.5.26: How are auto-increment columns in the MySQL database
     coordinated across multiple instances of memcached?

   * 15.6.5.27: Is compression available?

   * 15.6.5.28: What speed trade offs is there between `memcached' vs
     MySQL Query Cache? Where you check `memcached', and get data from
     MySQL and put it in `memcached' or just make a query and results
     are put into MySQL Query Cache.

   * 15.6.5.29: Can we implement different types of `memcached' as
     different nodes in the same server - so can there be deterministic
     and non deterministic in the same server?

   * 15.6.5.30: What are best practices for testing an implementation,
     to ensure that it is an improvement over the MySQL query cache,
     and to measure the impact of `memcached' configuration changes?
     And would you recommend keeping the configuration very simple to
     start?

*Questions and Answers* *15.6.5.1: ** Can MySQL actually trigger/store
the changed data to memcached?  *

Yes. You can use the MySQL UDFs for `memcached' and either write
statements that directly set the values in the `memcached' server, or
use triggers or stored procedures to do it for you. For more
information, see *Note ha-memcached-interfaces-mysqludf::

*15.6.5.2: ** Can memcached be run on a Windows environment?  *

No. Currently `memcached' is available only on the Unix/Linux platform.
There is an unofficial port available, see
`http://www.codeplex.com/memcachedproviders'.

*15.6.5.3: ** Does the `-L' flag automatically sense how much memory is
being used by other memcached?  *

No. There is no communication or sharing of information between
`memcached' instances.

*15.6.5.4: ** What is the max size of an object you can store in
memcache and is that configurable?  *

The default maximum object size is 1MB. In `memcached' 1.4.2 and later
you can change the maximum size of an object using the `-I' command
line option.

For versions before this, to increase this size, you have to re-compile
`memcached'. You can modify the value of the `POWER_BLOCK' within the
`slabs.c' file within the source.

In `memcached' 1.4.2 and higher you can configure the maximum supported
object size by using the `-I' command-line option. For example, to
increase the maximum object size to 5MB:

     $ memcached -I 5m

*15.6.5.5: ** Is it true `memcached' will be much more effective with
db-read-intensive applications than with db-write-intensive
applications?  *

Yes. `memcached' plays no role in database writes, it is a method of
caching data already read from the database in RAM.

*15.6.5.6: ** `memcached' is fast - is there any overhead in not using
persistent connections? If persistent is always recommended, what are
the downsides (for example, locking up)?  *

If you don't use persistent connections when communicating with
`memcached' then there will be a small increase in the latency of
opening the connection each time. The effect is comparable to use
nonpersistent connections with MySQL.

In general, the chance of locking or other issues with persistent
connections is minimal, because there is very little locking within
`memcached'. If there is a problem then eventually your request will
timeout and return no result so your application will need to load from
MySQL again.

*15.6.5.7: ** How does an event such as a crash of one of the
`memcached' servers handled by the `memcached' client?  *

There is no automatic handling of this. If your client fails to get a
response from a server then it should fall back to loading the data
from the MySQL database.

The client APIs all provide the ability to add and remove `memcached'
instances on the fly. If within your application you notice that
`memcached' server is no longer responding, your can remove the server
from the list of servers, and keys will automatically be redistributed
to another `memcached' server in the list. If retaining the cache
content on all your servers is important, make sure you use an API that
supports a consistent hashing algorithm. For more information, see
*Note ha-memcached-using-hashtypes::.

*15.6.5.8: ** What's a recommended hardware config for a memcached
server?  Linux or Windows?  *

`memcached' is only available on Unix/Linux, so using a Windows machine
is not an option. Outside of this, `memcached' has a very low
processing overhead.  All that is required is spare physical RAM
capacity. The point is not that you should necessarily deploy a
dedicated `memcached' server. If you have web, application, or database
servers that have spare RAM capacity, then use them with `memcached'.

If you want to build and deploy a dedicated `memcached' servers, then
you use a relatively low-power CPU, lots of RAM and one or more Gigabit
Ethernet interfaces.

*15.6.5.9: ** Doing a direct telnet to the memcached port, is that just
for that one machine, or does it magically apply across all nodes?  *

Just one. There is no communication between different instances of
`memcached', even if each instance is running on the same machine.

*15.6.5.10: ** Is memcached more effective for video and audio as
opposed to textual read/writes *

`memcached' doesn't care what information you are storing. To
`memcached', any value you store is just a stream of data. Remember,
though, that the maximum size of an object you can store in `memcached'
is 1MB, but can be configured to be larger by using the `-I' option in
`memcached' 1.4.2 and later, or by modifying the source in versions
before 1.4.2. If you plan on using `memcached' with audio and video
content you will probably want to increase the maximum object size. Also
remember that `memcached' is a solution for caching information for
reading. It shouldn't be used for writes, except when updating the
information in the cache.

*15.6.5.11: ** If you log a complex class (with methods that do
calculation etc) will the get from Memcache re-create the class on the
way out?  *

In general, yes. If the serialization method within the API/language
that you are using supports it, then methods and other information will
be stored and retrieved.

*15.6.5.12: ** If I have an object larger then a MB, do I have to
manually split it or can I configure `memcached' to handle larger
objects?  *

You would have to manually split it.  `memcached' is very simple, you
give it a key and some data, it tries to cache it in RAM. If you try to
store more than the default maximum size, the value is just truncated
for speed reasons.

*15.6.5.13: ** Can `memcached' work with `ASPX'?  *

There are ports and interfaces for many languages and environments.
ASPX relies on an underlying language such as C# or VisualBasic, and if
you are using ASP.NET then there is a C# `memcached' library. For more
information, see . (https://sourceforge.net/projects/memcacheddotnet/)

*15.6.5.14: ** Are there any, or are there any plans to introduce, a
framework to hide the interaction of memcached from the application;
that is, within hibernate?  *

There are lots of projects working with `memcached'. There is a Google
Code implementation of Hibernate and `memcached' working together. See
`http://code.google.com/p/hibernate-memcached/'.

*15.6.5.15: ** So the responsibility lies with the application to
populate and get records from the database as opposed to being a
transparent cache layer for the db?  *

Yes. You load the data from the database and write it into the cache
provided by `memcached'. Using `memcached' as a simple database row
cache, however, is probably inefficient. The best way to use
`memcached' is to load all of the information from the database
relating to a particular object, and then cache the entire object. For
example, in a blogging environment, you might load the blog, associated
comments, categories and so on, and then cache all of the information
relating to that blog post. The reading of the data from the database
will require multiple SQL statements and probably multiple rows of data
to complete, which is time consuming. Loading the entire blog post and
the associated information from `memcached' is just one operation and
doesn't involve using the disk or parsing the SQL statement.

*15.6.5.16: ** How does `memcached' compare to nCache?  *

The main benefit of `memcached' is that is very easy to deploy and
works with a wide range of languages and environments, including .NET,
Java, Perl, Python, PHP, even MySQL. `memcached' is also very
lightweight in terms of systems and requirements, and you can easily
add as many or as few `memcached' servers as you need without changing
the individual configuration.  `memcached' does require additional
modifications to the application to take advantage of functionality
such as multiple `memcached' servers.

*15.6.5.17: ** We are caching XML by serialising using saveXML(),
because PHP cannot serialize DOM objects; Some of the XML is variable
and is modified per-request. Do you recommend caching then using XPath,
or is it better to rebuild the DOM from separate node-groups?  *

You would need to test your application using the different methods to
determine this information. You may find that the default serialization
within PHP may allow you to store DOM objects directly into the cache.

*15.6.5.18: ** How easy is it to introduce `memcached' to an existing
enterprise application instead of inclusion at project design?  *

In general, it is very easy. In many languages and environments the
changes to the application will be just a few lines, first to attempt
to read from the cache when loading data and then fall back to the old
method, and to update the cache with information once the data has been
read.

`memcached' is designed to be deployed very easily, and you shouldn't
require significant architectural changes to your application to use
`memcached'.

*15.6.5.19: ** Do the memcache UDFs work under 5.1?  *

Yes.

*15.6.5.20: ** Is the data inside of `memcached' secure?  *

No, there is no security required to access or update the information
within a `memcached' instance, which means that anybody with access to
the machine has the ability to read, view and potentially update the
information. If you want to keep the data secure, you can encrypt and
decrypt the information before storing it. If you want to restrict the
users capable of connecting to the server, your only choice is to
either disable network access, or use IPTables or similar to restrict
access to the `memcached' ports to a select set of hosts.

*15.6.5.21: ** Is `memcached' typically a better solution for improving
speed than MySQL Cluster and\or MySQL Proxy?  *

Both MySQL Cluster and MySQL Proxy still require access to the
underlying database to retrieve the information. This implies both a
parsing overhead for the statement and, often, disk based access to
retrieve the data you have selected.

The advantage of `memcached' is that you can store entire objects or
groups of information that may require multiple SQL statements to
obtain. Restoring the result of 20 SQL statements formatted into a
structure that your application can use directly without requiring any
additional processing is always going to be faster than building that
structure by loading the rows from a database.

*15.6.5.22: ** File socket support for `memcached' from the localhost
use to the local memcached server?  *

You can use the `-s' option to `memcached' to specify the location of a
file socket. This automatically disables network support.

*15.6.5.23: ** How expensive is it to establish a memcache connection?
Should those connections be pooled?  *

Opening the connection is relatively inexpensive, because there is no
security, authentication or other handshake taking place before you can
start sending requests and getting results. Most APIs support a
persistent connection to a `memcached' instance to reduce the latency.
Connection pooling would depend on the API you are using, but if you
are communicating directly over TCP/IP, then connection pooling would
provide some small performance benefit.

*15.6.5.24: ** What are the advantages of using UDFs when the get/sets
are manageable from within the client code rather than the db?  *

Sometimes you want to be able to be able to update the information
within `memcached' based on a generic database activity, rather than
relying on your client code. For example, you may want to update status
or counter information in `memcached' through the use of a trigger or
stored procedure. For some situations and applications the existing use
of a stored procedure for some operations means that updating the value
in `memcached' from the database is easier than separately loading and
communicating that data to the client just so the client can talk to
`memcached.'

In other situations, when you are using a number of different clients
and different APIs, you don't want to have to write (and maintain) the
code required to update `memcached' in all the environments. Instead,
you do this from within the database and the client never gets involved.

*15.6.5.25: ** How will the data will be handled when the `memcached'
server is down?  *

The behavior is entirely application dependent. Most applications will
fall back to loading the data from the database (just as if they were
updating the `memcached') information. If you are using multiple
`memcached' servers, you may also want to remove a server from the list
to prevent the missing server affecting performance. This is because
the client will still attempt to communicate the `memcached' that
corresponds to the key you are trying to load.

*15.6.5.26: ** How are auto-increment columns in the MySQL database
coordinated across multiple instances of memcached?  *

They aren't. There is no relationship between MySQL and `memcached'
unless your application (or, if you are using the MySQL UDFs for
`memcached', your database definition) creates one.

If you are storing information based on an auto-increment key into
multiple instances of `memcached' then the information will only be
stored on one of the `memcached' instances anyway. The client uses the
key value to determine which `memcached' instance to store the
information, it doesn't store the same information across all the
instances, as that would be a waste of cache memory.

*15.6.5.27: ** Is compression available?  *

Yes. Most of the client APIs support some sort of compression, and some
even allow you to specify the threshold at which a value is deemed
appropriate for compression during storage.

*15.6.5.28: ** What speed trade offs is there between `memcached' vs
MySQL Query Cache? Where you check `memcached', and get data from MySQL
and put it in `memcached' or just make a query and results are put into
MySQL Query Cache.  *

In general, the time difference between getting data from the MySQL
Query Cache and getting the exact same data from `memcached' is very
small.

However, the benefit of `memcached' is that you can store any
information, including the formatted and processed results of many
queries into a single `memcached' key. Even if all the queries that you
executed could be retrieved from the Query Cache without having to go
to disk, you would still be running multiple queries (with network and
other overhead) compared to just one for the `memcached' equivalent. If
your application uses objects, or does any kind of processing on the
information, with `memcached' you can store the post-processed version,
so the data you load is immediately available to be used. With data
loaded from the Query Cache, you would still have to do that processing.

In addition to these considerations, keep in mind that keeping data in
the MySQL Query Cache is difficult as you have no control over the
queries that are stored. This means that a slightly unusual query can
temporarily clear a frequently used (and normally cached) query,
reducing the effectiveness of your Query Cache. With `memcached' you
can specify which objects are stored, when they are stored, and when
they should be deleted giving you much more control over the
information stored in the cache.

*15.6.5.29: ** Can we implement different types of `memcached' as
different nodes in the same server - so can there be deterministic and
non deterministic in the same server?  *

Yes. You can run multiple instances of `memcached' on a single server,
and in your client configuration you choose the list of servers you
want to use.

*15.6.5.30: ** What are best practices for testing an implementation,
to ensure that it is an improvement over the MySQL query cache, and to
measure the impact of `memcached' configuration changes? And would you
recommend keeping the configuration very simple to start?  *

The best way to test the performance is to start up a `memcached'
instance. First, modify your application so that it stores the data
just before the data is about to be used or displayed into
`memcached'.Since the APIs handle the serialization of the data, it
should just be a one line modification to your code. Then, modify the
start of the process that would normally load that information from
MySQL with the code that requests the data from `memcached'.  If the
data cannot be loaded from `memcached', default to the MySQL process.

All of the changes required will probably amount to just a few lines of
code. To get the best benefit, make sure you cache entire objects (for
example, all the components of a web page, blog post, discussion
thread, etc.), rather than using `memcached' as a simple cache of
individuals rows of MySQL tables. You should see performance benefits
almost immediately.

Keeping the configuration very simple at the start, or even over the
long term, is very easy with `memcached'.  Once you have the basic
structure up and running, the only change you may want to make is to
add more servers into the list of servers used by your clients. You
don't need to manage the `memcached' servers, and there is no complex
configuration, just add more servers to the list and let the client API
and the `memcached' servers make the decisions.


File: manual.info,  Node: mysql-proxy,  Prev: ha-memcached,  Up: ha-overview

15.7 MySQL Proxy
================

* Menu:

* mysql-proxy-platforms::        MySQL Proxy Supported Platforms
* mysql-proxy-install::          Installing MySQL Proxy
* mysql-proxy-configuration::    MySQL Proxy Command Options
* mysql-proxy-scripting::        MySQL Proxy Scripting
* mysql-proxy-using::            Using MySQL Proxy
* mysql-proxy-faq::              MySQL Proxy FAQ

The MySQL Proxy is an application that communicates over the network
using the MySQL network protocol and provides communication between one
or more MySQL servers and one or more MySQL clients. In the most basic
configuration, MySQL Proxy simply interposes itself between the server
and clients, passing queries from the clients to the MySQL Server and
returning the responses from the MySQL Server to the appropriate client.

Because MySQL Proxy uses the MySQL network protocol, it can be used
without modification with any MySQL-compatible client that uses the
protocol. This includes the *Note `mysql': mysql. command-line client,
any clients that uses the MySQL client libraries, and any connector
that supports the MySQL network protocol.

In addition to the basic pass-through configuration, the MySQL Proxy is
also capable of monitoring and altering the communication between the
client and the server. Query interception enables you to add profiling,
and interception of the exchanges is scriptable using the Lua scripting
language.

By intercepting the queries from the client, the proxy can insert
additional queries into the list of queries sent to the server, and
remove the additional results when they are returned by the server.
Using this functionality you can return the results from the original
query to the client while adding informational statements to each
query, for example, to monitor their execution time or progress, and
separately log the results.

The proxy enables you to perform additional monitoring, filtering, or
manipulation of queries without requiring you to make any modifications
to the client and without the client even being aware that it is
communicating with anything but a genuine MySQL server.

This documentation covers MySQL Proxy 0.8.0.

*Warning*:

MySQL Proxy is currently an Alpha release and should not be used within
production environments.

*Important*:

MySQL Proxy is compatible with MySQL 5.0 or later. Testing has not been
performed with Version 4.1. Please provide feedback on your experiences
using the MySQL Proxy Forum (http://forums.mysql.com/list.php?146).


File: manual.info,  Node: mysql-proxy-platforms,  Next: mysql-proxy-install,  Prev: mysql-proxy,  Up: mysql-proxy

15.7.1 MySQL Proxy Supported Platforms
--------------------------------------

MySQL Proxy is currently available as a precompiled binary for the
following platforms:

   * Linux (including Red Hat, Fedora, Debian, SuSE) and derivatives

   * Mac OS X

   * FreeBSD

   * IBM AIX

   * Sun Solaris

   * Microsoft Windows (including Microsoft Windows XP, Microsoft
     Windows Vista, Microsoft Windows Server 2003, Microsoft Windows
     Server 2008)

     *Note*:

     You must have the .NET Framework 1.1 or higher installed.

Other Unix/Linux platforms not listed should be compatible by using the
source package and building MySQL Proxy locally.

System requirements for the MySQL Proxy application are the same as the
main MySQL server. Currently MySQL Proxy is compatible only with MySQL
5.0.1 and later. MySQL Proxy is provided as a standalone, statically
linked binary. You need not have MySQL or Lua installed.


File: manual.info,  Node: mysql-proxy-install,  Next: mysql-proxy-configuration,  Prev: mysql-proxy-platforms,  Up: mysql-proxy

15.7.2 Installing MySQL Proxy
-----------------------------

* Menu:

* mysql-proxy-install-binary::   Installing MySQL Proxy from a Binary Distribution
* mysql-proxy-install-source::   Installing MySQL Proxy from a Source Distribution
* mysql-proxy-install-cvs::      Installing MySQL Proxy from the Bazaar Repository
* mysql-proxy-configuration-windows::  Setting Up MySQL Proxy as a Windows Service

You have three choices for installing MySQL Proxy:

   * Precompiled binaries are available for a number of different
     platforms. See *Note mysql-proxy-install-binary::.

   * You can install from the source code to build on an environment
     not supported by the binary distributions. See *Note
     mysql-proxy-install-source::.

   * The latest version of the MySQL Proxy source code is available
     through a development repository is the best way to stay up to
     date with the latest fixes and revisions. See *Note
     mysql-proxy-install-cvs::.


File: manual.info,  Node: mysql-proxy-install-binary,  Next: mysql-proxy-install-source,  Prev: mysql-proxy-install,  Up: mysql-proxy-install

15.7.2.1 Installing MySQL Proxy from a Binary Distribution
..........................................................

If you download a binary package, you must extract and copy the package
contents to your desired installation directory. The package contains
files required by MySQL Proxy, including additional Lua scripts and
other components required for execution.

To install, unpack the archive into the desired directory, then modify
your `PATH' environment variable so that you can use the *Note
`mysql-proxy': mysql-proxy. command directly:

     shell> cd /usr/local
     shell> tar zxf mysql-proxy-0.7.2-OSX10.5.tar.gz
     shell> PATH=$PATH:/usr/local/MYSQL-PROXY-0.7.2-OSX10.5-X86/sbin

To update the path globally on a system, you might need administrator
privileges to modify the appropriate `/etc/profile', `/etc/bashrc', or
other system configuration file.

On Windows, you can update the `PATH' environment variable using this
procedure:

  1. On the Windows desktop, right-click the `My Computer' icon, and
     select `Properties'.

  2. Next select the `Advanced' tab from the `System Properties' menu
     that appears, and click the `Environment Variables' button.

  3. Under `System Variables', select `Path', then click the `Edit'
     button. The `Edit System Variable' dialogue should appear.

The Microsoft Visual C++ runtime libraries are a requirement for
running MySQL Proxy as of version 0.8.2. Users that do not have these
libraries must download and install the Microsoft Visual C++ 2008
Service Pack 1 Redistributable Package MFC Security Update. Use the
following link to obtain the package:

     `http://www.microsoft.com/download/en/details.aspx?displaylang=en&id=26368'


File: manual.info,  Node: mysql-proxy-install-source,  Next: mysql-proxy-install-cvs,  Prev: mysql-proxy-install-binary,  Up: mysql-proxy-install

15.7.2.2 Installing MySQL Proxy from a Source Distribution
..........................................................

If you download a source package, you must compile the MySQL Proxy
before using it. A build from source requires that the following
prerequisite components be installed:

   * `libevent' 1.x or higher (1.3b or later is preferred)

   * `lua' 5.1.x or higher

   * `glib2' 2.6.0 or higher

   * `pkg-config'

   * `libtool' 1.5 or higher

   * MySQL 5.0.x or higher developer files

*Note*:

On some operating systems, you may need to manually build the required
components to get the latest version. If you have trouble compiling
MySQL Proxy, consider using a binary distributions instead.

After you have verified that the prerequisite components are installed,
configure and build MySQL Proxy:

     shell> tar zxf mysql-proxy-0.7.2.tar.gz
     shell> cd mysql-proxy-0.7.2
     shell> ./configure
     shell> make

To test the build, use the `check' target to `make':

     shell> make check

The tests try to connect to `localhost' using the `root' user. To
provide a password, set the `MYSQL_PASSWORD' environment variable:

     shell> MYSQL_PASSWORD=root_pwd make check

You can install using the `install' target:

     shell> make install

By default, *Note `mysql-proxy': mysql-proxy. is installed into
`/usr/local/sbin/mysql-proxy'. The Lua example scripts are installed
into `/usr/local/share'.


File: manual.info,  Node: mysql-proxy-install-cvs,  Next: mysql-proxy-configuration-windows,  Prev: mysql-proxy-install-source,  Up: mysql-proxy-install

15.7.2.3 Installing MySQL Proxy from the Bazaar Repository
..........................................................

The MySQL Proxy source is available through a public Bazaar repository
and is the quickest way to get the latest releases and fixes.

A build from the Bazaar repository requires that the following
prerequisite components be installed:

   * Bazaar 1.10.0 or later

   * `libtool' 1.5 or higher

   * `autoconf' 2.56 or higher

   * `automake' 1.10 or higher

   * `libevent' 1.x or higher (1.3b or later is preferred)

   * `lua' 5.1.x or higher

   * `glib2' 2.4.0 or higher

   * `pkg-config'

   * MySQL 5.0.x or higher developer files

The *Note `mysql-proxy': mysql-proxy. source is hosted on Launchpad. To
check out a local copy of the Bazaar repository, use `bzr':

     shell> bzr branch lp:mysql-proxy

The preceding command downloads a complete version of the Bazaar
repository for *Note `mysql-proxy': mysql-proxy. The main source files
are located within the `trunk' subdirectory. The configuration scripts
must be generated before you can configure and build *Note
`mysql-proxy': mysql-proxy. The `autogen.sh' script generates the
required configuration scripts for you:

     shell> sh ./autogen.sh

The `autogen.sh' script creates the standard `configure' script, which
you then use to configure and build with `make':

     shell> ./configure
     shell> make
     shell> make install

To create a standalone source distribution, identical to the source
distribution available for download, use this command:

     shell> make distcheck

The preceding command creates the file `mysql-proxy-0.7.2.tar.gz' (with
the corresponding current version) within the current directory.


File: manual.info,  Node: mysql-proxy-configuration-windows,  Prev: mysql-proxy-install-cvs,  Up: mysql-proxy-install

15.7.2.4 Setting Up MySQL Proxy as a Windows Service
....................................................

The MySQL distribution on Windows includes the `mysql-proxy-svc.exe'
command that enables a MySQL Proxy instance to be managed by the
Windows service control manager. This enables you to control the
service without separately running the MySQL Proxy application, and
allows for automatically starting and stopping the MySQL Proxy service
during boot, reboot and shutdown.

To set up a MySQL Proxy service, you must use the `sc' command to
create a new service using the MySQL Proxy service command. Specify the
MySQL Proxy options on the `sc' command line, and identify the service
with a unique name. For example, to configure a new MySQL Proxy
instance that will automatically start when your system boots,
redirecting queries to the local MySQL server:

     C:\> sc create "Proxy" DisplayName= "MySQL Proxy" start= "auto" »
       binPath= "C:\Program Files\MySQL\mysql-proxy-0.8.0\bin\mysql-proxy-svc.exe »
       --proxy-backend-addresses=127.0.0.1:3306"

*Note*:

The space following the equal sign after each property is required;
failure to include it results in an error.

The preceding command creates a new service called `Proxy'. You can
start and stop the service using the `net start|stop' command with the
service name. The service is not automatically started after it has
been created. To start the service:

     C:\> net start proxy
     The MySQL Proxy service is starting.
     The MySQL Proxy service was started successfully.

You can specify additional command-line options to the `sc' command.
You can also set up multiple MySQL Proxy services on the same machine
(providing they are configured to listen on different ports and/or IP
addresses.

You can delete a service that you have created:

     C:\> sc delete proxy

For more information on creating services using `sc', see How to create
a Windows service by using Sc.exe
(http://support.microsoft.com/kb/251192).


File: manual.info,  Node: mysql-proxy-configuration,  Next: mysql-proxy-scripting,  Prev: mysql-proxy-install,  Up: mysql-proxy

15.7.3 MySQL Proxy Command Options
----------------------------------

To start MySQL Proxy, you can run it directly from the command line:

     shell> mysql-proxy

However, for most situations, you specify at the very least the host
name or address and the port number of the backend MySQL server to
which the MySQL Proxy should pass queries.

You can specify options to *Note `mysql-proxy': mysql-proxy. either on
the command line, or by using a configuration file and the
`--defaults-file' command-line option to specify the file location.

If you use a configuration file, it should be formatted as follows:

   * Options must be specified within a `[mysql-proxy]' configuration
     group. For example:

          [mysql-proxy]
          admin-address = HOST:PORT

   * All configuration options should be specified in the form of a
     configuration name and the value to set.

   * For options that are a simple toggle on the command line (for
     example, `--proxy-skip-profiling'), you must use `true' or
     `false'. For example, the following is invalid:

          [mysql-proxy]
          proxy-skip-profiling

     But this is valid:

          [mysql-proxy]
          proxy-skip-profiling = true

   * The configuration file should have permissions of `0660' (readable
     and writable by user and group, no access for others).

Failure to adhere to any of these requirements causes *Note
`mysql-proxy': mysql-proxy. to generate an error during startup.

The following tables list the supported configuration file and
command-line options.

*`mysql-proxy' Help Options*

Format      Option File Description                   IntroductionDeprecatedRemoved
-help       help        Show help options                             
-help-admin help-admin  Show admin module options                     
-help-all   help-all    Show all help options                         
-help-proxy help-proxy  Show proxy module options                     

*`mysql-proxy' Admin Options*

Format      Option File Description                   IntroductionDeprecatedRemoved
-admin-address=host:portadmin-address=host:portThe admin module listening                    
                        host and port                                 
-admin-lua-script=file_nameadmin-lua-script=file_nameScript to execute by the                      
                        admin module                                  
-admin-password=passwordadmin-password=passwordAuthentication password for                   
                        admin module                                  
-admin-username=user_nameadmin-username=user_nameAuthentication user name for                  
                        admin module                                  
-proxy-address=host:portproxy-address=host:portThe listening proxy server                    
                        host and port                                 

*`mysql-proxy' Proxy Options*

Format      Option File Description                   IntroductionDeprecatedRemoved
-no-proxy   no-proxy    Do not start the proxy module                 
-proxy-backend-addresses=host:portproxy-backend-addresses=host:portThe MySQL server host and                     
                        port                                          
-proxy-fix-bug-25371proxy-fix-bug-25371Enable the fix for Bug                        0.8.1
                        #25371 for older libmysql                     
                        versions                                      
-proxy-lua-script=file_nameproxy-lua-script=file_nameFilename for Lua script for                   
                        proxy operations                              
-proxy-pool-no-change-userproxy-pool-no-change-userDo not use the protocol                       
                        CHANGE_USER command to reset                  
                        the  connection when coming                   
                        from the connection pool                      
-proxy-read-only-backend-addresses=host:portproxy-read-only-backend-addresses=host:portThe MySQL server host and                     
                        port (read only)                              
-proxy-skip-profilingproxy-skip-profilingDisable query profiling                       

*`mysql-proxy' Applications Options*

Format      Option File Description                   IntroductionDeprecatedRemoved
-basedir=dir_namebasedir=dir_nameThe base directory prefix                     
                        for paths in the                              
                        configuration                                 
-daemon     daemon      Start in daemon mode                          
-defaults-file=file_name            The configuration file to use                 
-event-threads=countevent-threads=countThe number of event-handling                  
                        threads                                       
-keepalive  keepalive   Try to restart the proxy if                   
                        a crash occurs                                
-log-backtrace-on-crashlog-backtrace-on-crashTry to invoke the debugger                    
                        and generate a backtrace on                   
                        crash                                         
-log-file=file_namelog-file=file_nameThe file where error                          
                        messages are logged                           
-log-level=levellog-level=levelThe logging level                             
-log-use-sysloglog-use-syslogLog errors to syslog                          
-lua-cpath=dir_namelua-cpath=dir_nameSet the LUA_CPATH                             
-lua-path=dir_namelua-path=dir_nameSet the LUA_PATH                              
-max-open-files=countmax-open-files=countThe maximum number of open                    
                        files to support                              
-pid-file=file_namepid-file=file_nameFile in which to store the                    
                        process ID                                    
-plugin-dir=dir_nameplugin-dir=dir_nameDirectory containing plugin                   
                        files                                         
-plugins=plugin,...plugins=plugin,...List of plugins to load                       
-user=user_nameuser=user_nameThe user to use when running                  
                        mysql-proxy                                   
-version    version     Show version information                      

Except as noted in the following details, all of the options can be
used within the configuration file by supplying the option and the
corresponding value. For example:

     [mysql-proxy]
     log-file = /var/log/mysql-proxy.log
     log-level = message

   *  `--help', `-h'

     Options for help      *Command-Line        `--help'        
     Format*                              
     **                   `-h'            
     *Option-File Format* `help'          


     Show available help options.

   *  `--help-admin'

     Options for help-admin      *Command-Line        `--help-admin'        
     Format*                              
     *Option-File Format* `help-admin'        


     Show options for the admin module.

   *  `--help-all'

     Options for help-all      *Command-Line        `--help-all'        
     Format*                              
     *Option-File Format* `help-all'        


     Show all help options.

   *  `--help-proxy'

     Options for help-proxy      *Command-Line        `--help-proxy'        
     Format*                              
     *Option-File Format* `help-proxy'        


     Show options for the proxy module.

   *  `--admin-address=HOST:PORT'

     Options for admin-address      *Command-Line        `--admin-address=host:port'        
     Format*                              
     *Option-File Format* `admin-address=host:port'        
                          *Permitted        
                          Values          
                          *               
     *Type*               `string'        
     *Default*            `:4041'         


     The host name (or IP address) and port for the administration
     port. The default is `localhost:4041'.

   *  `--admin-lua-script=FILE_NAME'

     Options for admin-lua-script      *Command-Line        `--admin-lua-script=file_name'        
     Format*                              
     *Option-File Format* `admin-lua-script=file_name'        
                          *Permitted        
                          Values          
                          *               
     *Type*               `file           
                          name'           
     *Default*            `'              


     The script to use for the proxy administration module.

   *  `--admin-password=PASSWORD'

     Options for admin-password      *Command-Line        `--admin-password=password'        
     Format*                              
     *Option-File Format* `admin-password=password'        
                          *Permitted        
                          Values          
                          *               
     *Type*               `string'        
     *Default*            `'              


     The password to use to authenticate users wanting to connect to
     the MySQL Proxy administration module. This module uses the MySQL
     protocol to request a user name and password for connections.

   *  `--admin-username=USER_NAME'

     Options for admin-username      *Command-Line        `--admin-username=user_name'        
     Format*                              
     *Option-File Format* `admin-username=user_name'        
                          *Permitted        
                          Values          
                          *               
     *Type*               `string'        
     *Default*            `root'          


     The user name to use to authenticate users wanting to connect to
     the MySQL Proxy administration module. This module uses the MySQL
     protocol to request a user name and password for connections. The
     default user name is `root'.

   *  `--basedir=DIR_NAME'

     Options for basedir      *Command-Line        `--basedir=dir_name'        
     Format*                              
     *Option-File Format* `basedir=dir_name'        
                          *Permitted        
                          Values          
                          *               
     *Type*               `directory        
                          name'           


     The base directory to use as a prefix for all other file name
     configuration options. The base name should be an absolute (not
     relative) directory. If you specify a relative directory, *Note
     `mysql-proxy': mysql-proxy. generates an error during startup.

   *  `--daemon'

     Options for daemon      *Command-Line        `--daemon'        
     Format*                              
     *Option-File Format* `daemon'        


     Starts the proxy in daemon mode.

   *  `--defaults-file=FILE_NAME'

     Options for defaults-file      *Command-Line        `--defaults-file=file_name'        
     Format*                              


     The file to read for configuration options. If not specified,
     MySQL Proxy takes options only from the command line.

   *  `--event-threads=COUNT'

     Options for event-threads      *Command-Line        `--event-threads=count'        
     Format*                              
     *Option-File Format* `event-threads=count'        
                          *Permitted        
                          Values          
                          *               
     *Type*               `numeric'        
     *Default*            `1'             


     The number of event threads to reserve to handle incoming requests.

   *  `--keepalive'

     Options for keepalive      *Command-Line        `--keepalive'        
     Format*                              
     *Option-File Format* `keepalive'        


     Create a process surrounding the main *Note `mysql-proxy':
     mysql-proxy. process that attempts to restart the main *Note
     `mysql-proxy': mysql-proxy. process in the event of a crash or
     other failure.

     *Note*:

     The `--keepalive' option is not available on Microsoft Windows.
     When running as a service, *Note `mysql-proxy': mysql-proxy.
     automatically restarts.

   *  `--log-backtrace-on-crash'

     Options for log-backtrace-on-crash      *Command-Line        `--log-backtrace-on-crash'        
     Format*                              
     *Option-File Format* `log-backtrace-on-crash'        


     Log a backtrace to the error log and try to initialize the
     debugger in the event of a failure.

   *  `--log-file=FILE_NAME'

     Options for log-file      *Command-Line        `--log-file=file_name'        
     Format*                              
     *Option-File Format* `log-file=file_name'        
                          *Permitted        
                          Values          
                          *               
     *Type*               `file           
                          name'           


     The file to use to record log information. If this option is not
     given, *Note `mysql-proxy': mysql-proxy. logs to the standard
     error output.

   *  `--log-level=LEVEL'

     Options for log-level      *Command-Line        `--log-level=level'        
     Format*                              
     *Option-File Format* `log-level=level'        
                          *Permitted        
                          Values          
                          *               
     *Type*               `enumeration'        
     *Valid Values*       `error'         
                          `warning'        
                          `info'          
                          `message'        
                          `debug'         


     The log level to use when outputting error messages. Messages with
     that level (or lower) are output. For example, `message' level
     also outputs message with `info', `warning', and `error' levels.

   *  `--log-use-syslog'

     Options for log-use-syslog      *Command-Line        `--log-use-syslog'        
     Format*                              
     *Option-File Format* `log-use-syslog'        


     Log errors to the syslog (Unix/Linux only).

   *  `--lua-cpath=DIR_NAME'

     Options for lua-cpath      *Command-Line        `--lua-cpath=dir_name'        
     Format*                              
     *Option-File Format* `lua-cpath=dir_name'        
                          *Permitted        
                          Values          
                          *               
     *Type*               `directory        
                          name'           


     The `LUA_CPATH' to use when loading compiled modules or libraries
     for Lua scripts.

   *  `--lua-path=DIR_NAME'

     Options for lua-path      *Command-Line        `--lua-path=dir_name'        
     Format*                              
     *Option-File Format* `lua-path=dir_name'        
                          *Permitted        
                          Values          
                          *               
     *Type*               `directory        
                          name'           


     The `LUA_CPATH' to use when loading modules for Lua.

   *  `--max-open-files=COUNT'

     Options for max-open-files      *Command-Line        `--max-open-files=count'        
     Format*                              
     *Option-File Format* `max-open-files=count'        
                          *Permitted        
                          Values          
                          *               
     *Type*               `numeric'        


     The maximum number of open files and sockets supported by the
     *Note `mysql-proxy': mysql-proxy. process. Certain scripts might
     require a higher value.

   *  `--no-proxy'

     Options for no-proxy      *Command-Line        `--no-proxy'        
     Format*                              
     *Option-File Format* `no-proxy'        


     Disable the proxy module.

   *  `--plugin-dir=DIR_NAME'

     Options for plugin-dir      *Command-Line        `--plugin-dir=dir_name'        
     Format*                              
     *Option-File Format* `plugin-dir=dir_name'        
                          *Permitted        
                          Values          
                          *               
     *Type*               `directory        
                          name'           


     The directory to use when loading plugins for *Note `mysql-proxy':
     mysql-proxy.

   *  `--plugins=PLUGIN,...'

     Options for plugins      *Command-Line        `--plugins=plugin,...'        
     Format*                              
     *Option-File Format* `plugins=plugin,...'        
                          *Permitted        
                          Values          
                          *               
     *Type*               `string'        


     A comma-separated list of plugins to load.

   *  `--proxy-address=HOST:PORT', `-P HOST:PORT'

     Options for proxy-address      *Command-Line        `--proxy-address=host:port'        
     Format*                              
     **                   `-P             
                          host:port'        
     *Option-File Format* `proxy-address=host:port'        
                          *Permitted        
                          Values          
                          *               
     *Type*               `string'        
     *Default*            `:4040'         


     The listening host name (or IP address) and port of the proxy
     server. The default is `:4040' (all IPs on port 4040).

   *  `--proxy-read-only-backend-addresses=HOST:PORT', `-r HOST:PORT'

     Options for proxy-read-only-backend-addresses      *Command-Line        `--proxy-read-only-backend-addresses=host:port'        
     Format*                              
     **                   `-r             
                          host:port'        
     *Option-File Format* `proxy-read-only-backend-addresses=host:port'        
                          *Permitted        
                          Values          
                          *               
     *Type*               `string'        


     The listening host name (or IP address) and port of the proxy
     server for read-only connections. The default is for this
     information not to be set.

     *Note*:

     Setting this value only configures the servers within the
     corresponding internal structure (see `proxy.global.backends').
     You can determine the backend type by checking the `type' field
     for each connection.

     You should therefore only use this option in combination with a
     script designed to make use of the different backend types.

     When using this option on the command line, you can specify the
     option and the server multiple times to specify multiple backends.
     For example:

          shell> mysql-proxy --proxy-read-only-backend-addresses 192.168.0.1:3306 --proxy-read-only-backend-addresses 192.168.0.2:3306

     When using the option within the configuration file, you should
     separate multiple servers by commas. The equivalent of the
     preceding example would be:

          ...
          proxy-read-only-backend-addresses = 192.168.0.1:3306,192.168.0.2:3306

   *  `--proxy-backend-addresses=HOST:PORT', `-b HOST:PORT'

     Options for proxy-backend-addresses      *Command-Line        `--proxy-backend-addresses=host:port'        
     Format*                              
     **                   `-b             
                          host:port'        
     *Option-File Format* `proxy-backend-addresses=host:port'        
                          *Permitted        
                          Values          
                          *               
     *Type*               `string'        
     *Default*            `127.0.0.1:3306'        


     The host name (or IP address) and port of the MySQL server to
     connect to. You can specify multiple backend servers by supplying
     multiple options. Clients are connected to each backend server in
     round-robin fashion. For example, if you specify two servers A and
     B, the first client connection will go to server A; the second
     client connection to server B and the third client connection to
     server A.

     When using this option on the command line, you can specify the
     option and the server multiple times to specify multiple backends.
     For example:

          shell> mysql-proxy --proxy-backend-addresses 192.168.0.1:3306 --proxy-backend-addresses 192.168.0.2:3306

     When using the option within the configuration file, you should
     separate multiple servers by commas. The equivalent of the
     preceding example would be:

          ...
          proxy-backend-addresses = 192.168.0.1:3306,192.168.0.2:3306

   *  `--proxy-pool-no-change-user'

     Options for proxy-pool-no-change-user      *Command-Line        `--proxy-pool-no-change-user'        
     Format*                              
     *Option-File Format* `proxy-pool-no-change-user'        


     Disable use of the MySQL protocol `CHANGE_USER' command when
     reusing a connection from the pool of connections specified by the
     `proxy-backend-addresses' list.

   *  `--proxy-skip-profiling'

     Options for proxy-skip-profiling      *Command-Line        `--proxy-skip-profiling'        
     Format*                              
     *Option-File Format* `proxy-skip-profiling'        


     Disable query profiling (statistics time tracking). The default is
     for tracking to be enabled.

   *  `--proxy-fix-bug-25371'

     Options for proxy-fix-bug-25371      *Version Removed*    0.8.1           
     *Command-Line        `--proxy-fix-bug-25371'        
     Format*                              
     *Option-File Format* `proxy-fix-bug-25371'        


     Enable a workaround for an issue when connecting to a MySQL server
     later than 5.1.12 when using a MySQL client library of any earlier
     version.

     This option was removed in *Note `mysql-proxy': mysql-proxy.
     0.8.1. Now, *Note `mysql-proxy': mysql-proxy. returns an error
     message at the protocol level if it sees a `COM_CHANGE_USER' being
     sent to a server that has a version from 5.1.14 to 5.1.17.

   *  `--proxy-lua-script=FILE_NAME', `-s FILE_NAME'

     Options for proxy-lua-script      *Command-Line        `--proxy-lua-script=file_name'        
     Format*                              
     **                   `-s             
                          file_name'        
     *Option-File Format* `proxy-lua-script=file_name'        
                          *Permitted        
                          Values          
                          *               
     *Type*               `file           
                          name'           


     The Lua script file to be loaded. Note that the script file is not
     physically loaded and parsed until a connection is made.  Also
     note that the specified Lua script is reloaded for each
     connection; if the content of the Lua script changes while *Note
     `mysql-proxy': mysql-proxy. is running, the updated content is
     automatically used when a new connection is made.

   *  `--pid-file=FILE_NAME'

     Options for pid-file      *Command-Line        `--pid-file=file_name'        
     Format*                              
     *Option-File Format* `pid-file=file_name'        
                          *Permitted        
                          Values          
                          *               
     *Type*               `file           
                          name'           


     The name of the file in which to store the process ID.

   *  `--user=USER_NAME'

     Options for user      *Command-Line        `--user=user_name'        
     Format*                              
     *Option-File Format* `user=user_name'        
                          *Permitted        
                          Values          
                          *               
     *Type*               `string'        


     Run *Note `mysql-proxy': mysql-proxy. as the specified `user'.

   *  `--version', `-V'

     Options for version      *Command-Line        `--version'        
     Format*                              
     **                   `-V'            
     *Option-File Format* `version'        


     Show the version number.

The most common usage is as a simple proxy service (that is, without
additional scripting). For basic proxy operation, you must specify at
least one `proxy-backend-addresses' option to specify the MySQL server
to connect to by default:

     shell> mysql-proxy --proxy-backend-addresses=MySQL.example.com:3306

The default proxy port is `4040', so you can connect to your MySQL
server through the proxy by specifying the host name and port details:

     shell> mysql --host=localhost --port=4040

If your server requires authentication information, this will be passed
through natively without alteration by *Note `mysql-proxy':
mysql-proxy, so you must also specify the required authentication
information:

     shell> mysql --host=localhost --port=4040 \
        --user=user_name --password=password

You can also connect to a read-only port (which filters out *Note
`UPDATE': update. and *Note `INSERT': insert. queries) by connecting to
the read-only port. By default the host name is the default, and the
port is `4042', but you can alter the host/port information by using the
`--proxy-read-only-backend-addresses' command-line option.

For more detailed information on how to use these command-line options,
and *Note `mysql-proxy': mysql-proxy. in general in combination with
Lua scripts, see *Note mysql-proxy-using::.


File: manual.info,  Node: mysql-proxy-scripting,  Next: mysql-proxy-using,  Prev: mysql-proxy-configuration,  Up: mysql-proxy

15.7.4 MySQL Proxy Scripting
----------------------------

* Menu:

* mysql-proxy-scripting-injection::  Proxy Scripting Sequence During Query Injection
* mysql-proxy-scripting-structures::  Internal Structures
* mysql-proxy-scripting-connect-server::  Capturing a Connection with `connect_server()'
* mysql-proxy-scripting-read-handshake::  Examining the Handshake with `read_handshake()'
* mysql-proxy-scripting-read-auth::  Examining the Authentication Credentials with `read_auth()'
* mysql-proxy-scripting-read-auth-result::  Accessing Authentication Information with `read_auth_result()'
* mysql-proxy-scripting-read-query::  Manipulating Queries with `read_query()'
* mysql-proxy-scripting-read-query-result::  Manipulating Results with `read_query_result()'

You can control how MySQL Proxy manipulates and works with the queries
and results that are passed on to the MySQL server through the use of
the embedded Lua scripting language. You can find out more about the
Lua programming language from the Lua Web site (http://www.lua.org).

The following diagram shows an overview of the classes exposed by MySQL
Proxy.

MySQL Proxy architecture

The primary interaction between MySQL Proxy and the server is provided
by defining one or more functions through an Lua script.  A number of
functions are supported, according to different events and operations
in the communication sequence between a client and one or more backend
MySQL servers:

   * `connect_server()': This function is called each time a connection
     is made to MySQL Proxy from a client.  You can use this function
     during load-balancing to intercept the original connection and
     decide which server the client should ultimately be attached to.
     If you do not define a special solution, a simple round-robin
     style distribution is used by default.

   * `read_handshake()': This function is called when the initial
     handshake information is returned by the server. You can capture
     the handshake information returned and provide additional checks
     before the authorization exchange takes place.

   * `read_auth()': This function is called when the authorization
     packet (user name, password, default database) are submitted by
     the client to the server for authentication.

   * `read_auth_result()': This function is called when the server
     returns an authorization packet to the client indicating whether
     the authorization succeeded.

   * `read_query()': This function is called each time a query is sent
     by the client to the server. You can use this to edit and
     manipulate the original query, including adding new queries before
     and after the original statement.  You can also use this function
     to return information directly to the client, bypassing the
     server, which can be useful to filter unwanted queries or queries
     that exceed known limits.

   * `read_query_result()': This function is called each time a result
     is returned from the server, providing you have manually injected
     queries into the query queue. If you have not explicitly injected
     queries within the `read_query()' function, this function is not
     triggered. You can use this to edit the result set, or to remove
     or filter the result sets generated from additional queries you
     injected into the queue when using `read_query()'.

The following table describes the direction of information flow at the
point when the function is triggered.

Function               Supplied Information   Direction
`connect_server()'     None                   Client to Server
`read_handshake()'     None                   Server to Client
`read_auth()'          None                   Client to Server
`read_auth_result()'   None                   Server to Client
`read_query()'         Query                  Client to Server
`read_query_result()'  Query result           Server to Client

By default, all functions return a result that indicates whether the
data should be passed on to the client or server (depending on the
direction of the information being transferred). This return value can
be overridden by explicitly returning a constant indicating that a
particular response should be sent. For example, it is possible to
construct result set information by hand within `read_query()' and to
return the result set directly to the client without ever sending the
original query to the server.

In addition to these functions, a number of built-in structures provide
control over how MySQL Proxy forwards queries and returns the results
by providing a simplified interface to elements such as the list of
queries and the groups of result sets that are returned.


File: manual.info,  Node: mysql-proxy-scripting-injection,  Next: mysql-proxy-scripting-structures,  Prev: mysql-proxy-scripting,  Up: mysql-proxy-scripting

15.7.4.1 Proxy Scripting Sequence During Query Injection
........................................................

The following figure gives an example of how the proxy might be used
when injecting queries into the query queue. Because the proxy sits
between the client and MySQL server, what the proxy sends to the
server, and the information that the proxy ultimately returns to the
client, need not match or correlate.  Once the client has connected to
the proxy, the sequence shown in the following diagram occurs for each
individual query sent by the client.

MySQL Proxy architecture

  1. When the client submits one query to the proxy, the `read_query()'
     function within the proxy is triggered. The function adds the
     query to the query queue.

  2. Once manipulation by `read_query()' has completed, the queries are
     submitted, sequentially, to the MySQL server.

  3. The MySQL server returns the results from each query, one result
     set for each query submitted. The `read_query_result()' function is
     triggered for each result set, and each invocation can decide
     which result set to return to the client

For example, you can queue additional queries into the global query
queue to be processed by the server. This can be used to add
statistical information by adding queries before and after the original
query, changing the original query:

     SELECT * FROM City;

Into a sequence of queries:

     SELECT NOW();
     SELECT * FROM City;
     SELECT NOW();

You can also modify the original statement; for example, to add *Note
`EXPLAIN': explain. to each statement executed to get information on
how the statement was processed, again altering our original SQL
statement into a number of statements:

     SELECT * FROM City;
     EXPLAIN SELECT * FROM City;

In both of these examples, the client would have received more result
sets than expected. Regardless of how you manipulate the incoming query
and the returned result, the number of queries returned by the proxy
must match the number of original queries sent by the client.

You could adjust the client to handle the multiple result sets sent by
the proxy, but in most cases you will want the existence of the proxy
to remain transparent. To ensure that the number of queries and result
sets match, you can use the MySQL Proxy `read_query_result()' to
extract the additional result set information and return only the
result set the client originally requested back to the client. You can
achieve this by giving each query that you add to the query queue a
unique ID, then filter out queries that do not match the original query
ID when processing them with `read_query_result()'.


File: manual.info,  Node: mysql-proxy-scripting-structures,  Next: mysql-proxy-scripting-connect-server,  Prev: mysql-proxy-scripting-injection,  Up: mysql-proxy-scripting

15.7.4.2 Internal Structures
............................

There are a number of internal structures within the scripting element
of MySQL Proxy. The primary structure is `proxy' and this provides an
interface to the many common structures used throughout the script,
such as connection lists and configured backend servers. Other
structures, such as the incoming packet from the client and result sets
are only available within the context of one of the scriptable
functions.

Attribute              Description
`connection'           A structure containing the active client
                       connections. For a list of attributes, see
                       `proxy.connection'.
`servers'              A structure containing the list of configured
                       backend servers. For a list of attributes, see
                       `proxy.global.backends'.
`queries'              A structure containing the queue of queries that
                       will be sent to the server during a single client
                       query. For a list of attributes, see
                       `proxy.queries'.
`PROXY_VERSION'        The version number of MySQL Proxy, encoded in
                       hex. You can use this to check that the version
                       number supports a particular option from within
                       the Lua script. Note that the value is encoded as
                       a hex value, so to check the version is at least
                       0.5.1 you compare against `0x00501'.

*`proxy.connection'*

The `proxy.connection' object is read only, and provides information
about the current connection, and is split into a `client' and `server'
tables. This enables you to examine information about both the incoming
client connections to the proxy (`client'), and to the backend servers
(`server').

Attribute              Description
`client.default_db'    Default database requested by the client
`client.username'      User name used to authenticate
`client.scrambled_password'The scrambled version of the password used to
                       authenticate
`client.dst.name'      The combined `address:port' of the Proxy port
                       used by this client (should match the
                       `--proxy-address' configuration parameter)
`client.dst.address'   The IP address of the of the Proxy port used by
                       this client
`client.dst.port'      The port number of the of the Proxy port used by
                       this client
`client.src.name'      The combined `address:port' of the client
                       (originating) TCP/IP endpoint
`client.src.address'   The IP address of the client (originating) TCP/IP
                       port
`client.src.port'      The port of the client (originating) TCP/IP
                       endpoint
`server.scramble_buffer'The scramble buffer used to scramble the password
`server.mysqld_version'The MySQL version number of the server
`server.thread_id'     The ID of the thread handling the connection to
                       the current server
`server.dst.name'      The combined `address:port' for the backend
                       server for the current connection (i.e. the
                       connection to the MySQL server)
`server.dst.address'   The address for the backend server
`server.dst.port'      The port for the backend server
`server.src.name'      The combined `address:port' for the TCP/IP
                       endpoint used by the Proxy to connect to the
                       backend server
`server.src.address'   The address of the endpoint for the proxy-side
                       connection to the MySQL server
`server.src.port'      The port of the endpoint for the proxy-side
                       connection to the MySQL server

*`proxy.global.backends'*

The `proxy.global.backends' table is partially writable and contains an
array of all the configured backend servers and the server metadata (IP
address, status, etc.). You can determine the array index of the
current connection using `proxy.connection["backend_ndx"]' which is the
index into this table of the backend server being used by the active
connection.

The attributes for each entry within the `proxy.global.backends' table
are shown in this table.

Attribute              Description
`dst.name'             The combined `address:port' of the backend server.
`dst.address'          The IP address of the backend server.
`dst.port'             The port of the backend server.
`connected_clients'    The number of clients currently connected.
`state'                The status of the backend server. See *Note
                       mysql-proxy-scripting-structures-backend-states::.
`type'                 The type of the backend server. You can use this
                       to identify whether the backed was configured as
                       a standard read/write backend, or a read-only
                       backend. You can compare this value to the
                       `proxy.BACKEND_TYPE_RW' and
                       `proxy.BACKEND_TYPE_RO'.

*`proxy.queries'*

The `proxy.queries' object is a queue representing the list of queries
to be sent to the server. The queue is not populated automatically, but
if you do not explicitly populate the queue, queries are passed on to
the backend server verbatim. Also, if you do not populate the query
queue by hand, the `read_query_result()' function is not triggered.

The following methods are supported for populating the `proxy.queries'
object.

Function               Description
`append(id,packet,[options])'Appends a query to the end of the query queue.
                       The `id' is an integer identifier that you can
                       use to recognize the query results when they are
                       returned by the server.  The packet should be a
                       properly formatted query packet.  The optional
                       `options' should be a table containing the
                       options specific to this packet.
`prepend(id,packet)'   Prepends a query to the query queue. The `id' is
                       an identifier that you can use to recognize the
                       query results when they are returned by the
                       server. The packet should be a properly formatted
                       query packet.
`reset()'              Empties the query queue.
`len()'                Returns the number of query packets in the queue.

For example, you could append a query packet to the `proxy.queries'
queue by using the `append()':

     proxy.queries:append(1,packet)

The optional third argument to `append()' should contain the options
for the packet. To have access to the result set through the
`read_query_result()' function, set the `resultset_is_needed' flag to
`true':

     proxy.queries:append( 1, packet, { resultset_is_needed = true } )

If that flag is `false' (the default), proxy will:

   * Send the result set to the client as soon as it is received

   * Reduce memory usage (because the result set is not stored
     internally for processing)

   * Reduce latency of returning results to the client

   * Pass data from server to client unaltered

The default mode is therefore quicker and useful if you only want to
monitor the queries sent, and the basic statistics.

To perform any kind of manipulation on the returned data, you must set
the flag to `true', which will:

   * Store the result set so that it can be processed.

   * Enable modification of the result set before it is returned to the
     client.

   * Enable you to discard the result set instead of returning it to
     the client.

*`proxy.response'*

The `proxy.response' structure is used when you want to return your own
MySQL response, instead of forwarding a packet that you have received a
backend server. The structure holds the response type information, an
optional error message, and the result set (rows/columns) to return.

Attribute              Description
`type'                 The type of the response. The type must be either
                       `MYSQLD_PACKET_OK' or `MYSQLD_PACKET_ERR'. If the
                       `MYSQLD_PACKET_ERR', you should set the value of
                       the `mysql.response.errmsg' with a suitable error
                       message.
`errmsg'               A string containing the error message that will
                       be returned to the client.
`resultset'            A structure containing the result set information
                       (columns and rows), identical to what would be
                       returned when returning a results from a *Note
                       `SELECT': select.  query.

When using `proxy.response' you either set `proxy.response.type' to
`proxy.MYSQLD_PACKET_OK' and then build `resultset' to contain the
results to return, or set `proxy.response.type' to
`proxy.MYSQLD_PACKET_ERR' and set the `proxy.response.errmsg' to a
string with the error message. To send the completed result set or error
message, you should return the `proxy.PROXY_SEND_RESULT' to trigger the
return of the packet information.

An example of this can be seen in the `tutorial-resultset.lua' script
within the MySQL Proxy package:

     if string.lower(command) == "show" and string.lower(option) == "querycounter" then
             ---
             -- proxy.PROXY_SEND_RESULT requires
             --
             -- proxy.response.type to be either
             -- * proxy.MYSQLD_PACKET_OK or
             -- * proxy.MYSQLD_PACKET_ERR
             --
             -- for proxy.MYSQLD_PACKET_OK you need a resultset
             -- * fields
             -- * rows
             --
             -- for proxy.MYSQLD_PACKET_ERR
             -- * errmsg
             proxy.response.type = proxy.MYSQLD_PACKET_OK
             proxy.response.resultset = {
                     fields = {
                             { type = proxy.MYSQL_TYPE_LONG, name = "global_query_counter", },
                             { type = proxy.MYSQL_TYPE_LONG, name = "query_counter", },
                     },
                     rows = {
                             { proxy.global.query_counter, query_counter }
                     }
             }

             -- we have our result, send it back
             return proxy.PROXY_SEND_RESULT
     elseif string.lower(command) == "show" and string.lower(option) == "myerror" then
             proxy.response.type = proxy.MYSQLD_PACKET_ERR
             proxy.response.errmsg = "my first error"

             return proxy.PROXY_SEND_RESULT

*`proxy.response.resultset'*

The `proxy.response.resultset' structure should be populated with the
rows and columns of data to return. The structure contains the
information about the entire result set, with the individual elements
of the data shown in the following table.

Attribute              Description
`fields'               The definition of the columns being returned.
                       This should be a dictionary structure with the
                       `type' specifying the MySQL data type, and the
                       `name' specifying the column name.  Columns
                       should be listed in the order of the column data
                       that will be returned.
`flags'                A number of flags related to the result set.
                       Valid flags include `auto_commit' (whether an
                       automatic commit was triggered),
                       `no_good_index_used' (the query executed without
                       using an appropriate index), and `no_index_used'
                       (the query executed without using any index).
`rows'                 The actual row data. The information should be
                       returned as an array of arrays. Each inner array
                       should contain the column data, with the outer
                       array making up the entire result set.
`warning_count'        The number of warnings for this result set.
`affected_rows'        The number of rows affected by the original
                       statement.
`insert_id'            The last insert ID for an auto-incremented column
                       in a table.
`query_status'         The status of the query operation. You can use the
                       `MYSQLD_PACKET_OK' or `MYSQLD_PACKET_ERR'
                       constants to populate this parameter.

For an example showing how to use this structure, see `proxy.response'.

*Proxy Return State Constants*

The following constants are used internally by the proxy to specify the
response to send to the client or server. All constants are exposed as
values within the main `proxy' table.

Constant               Description
`PROXY_SEND_QUERY'     Causes the proxy to send the current contents of
                       the queries queue to the server.
`PROXY_SEND_RESULT'    Causes the proxy to send a result set back to the
                       client.
`PROXY_IGNORE_RESULT'  Causes the proxy to drop the result set (nothing
                       is returned to the client).

As constants, these entities are available without qualification in the
Lua scripts. For example, at the end of the `read_query_result()' you
might return `PROXY_IGNORE_RESULT:'

     return proxy.PROXY_IGNORE_RESULT

*Packet State Constants*

The following states describe the status of a network packet.  These
items are entries within the main `proxy' table.

Constant               Description
`MYSQLD_PACKET_OK'     The packet is OK
`MYSQLD_PACKET_ERR'    The packet contains error information
`MYSQLD_PACKET_RAW'    The packet contains raw data

*Backend State/Type Constants*

The following constants are used either to define the status or type of
the backend MySQL server to which the proxy is connected. These items
are entries within the main `proxy' table.

Constant               Description
`BACKEND_STATE_UNKNOWN'The current status is unknown
`BACKEND_STATE_UP'     The backend is known to be up (available)
`BACKEND_STATE_DOWN'   The backend is known to be down (unavailable)
`BACKEND_TYPE_UNKNOWN' Backend type is unknown
`BACKEND_TYPE_RW'      Backend is available for read/write
`BACKEND_TYPE_RO'      Backend is available only for read-only use

*Server Command Constants*

The following values are used in the packets exchanged between the
client and server to identify the information in the rest of the
packet. These items are entries within the main `proxy' table. The
packet type is defined as the first character in the sent packet. For
example, when intercepting packets from the client to edit or monitor a
query, you would check that the first byte of the packet was of type
`proxy.COM_QUERY'.

Constant               Description
`COM_SLEEP'            Sleep
`COM_QUIT'             Quit
`COM_INIT_DB'          Initialize database
`COM_QUERY'            Query
`COM_FIELD_LIST'       Field List
`COM_CREATE_DB'        Create database
`COM_DROP_DB'          Drop database
`COM_REFRESH'          Refresh
`COM_SHUTDOWN'         Shutdown
`COM_STATISTICS'       Statistics
`COM_PROCESS_INFO'     Process List
`COM_CONNECT'          Connect
`COM_PROCESS_KILL'     Kill
`COM_DEBUG'            Debug
`COM_PING'             Ping
`COM_TIME'             Time
`COM_DELAYED_INSERT'   Delayed insert
`COM_CHANGE_USER'      Change user
`COM_BINLOG_DUMP'      Binlog dump
`COM_TABLE_DUMP'       Table dump
`COM_CONNECT_OUT'      Connect out
`COM_REGISTER_SLAVE'   Register slave
`COM_STMT_PREPARE'     Prepare server-side statement
`COM_STMT_EXECUTE'     Execute server-side statement
`COM_STMT_SEND_LONG_DATA'Long data
`COM_STMT_CLOSE'       Close server-side statement
`COM_STMT_RESET'       Reset statement
`COM_SET_OPTION'       Set option
`COM_STMT_FETCH'       Fetch statement
`COM_DAEMON'           Daemon (MySQL 5.1 only)
`COM_ERROR'            Error

*MySQL Type Constants*

These constants are used to identify the field types in the query
result data returned to clients from the result of a query. These items
are entries within the main `proxy' table.

Constant               Field Type
`MYSQL_TYPE_DECIMAL'   Decimal
`MYSQL_TYPE_NEWDECIMAL'Decimal (MySQL 5.0 or later)
`MYSQL_TYPE_TINY'      Tiny
`MYSQL_TYPE_SHORT'     Short
`MYSQL_TYPE_LONG'      Long
`MYSQL_TYPE_FLOAT'     Float
`MYSQL_TYPE_DOUBLE'    Double
`MYSQL_TYPE_NULL'      Null
`MYSQL_TYPE_TIMESTAMP' Timestamp
`MYSQL_TYPE_LONGLONG'  Long long
`MYSQL_TYPE_INT24'     Integer
`MYSQL_TYPE_DATE'      Date
`MYSQL_TYPE_TIME'      Time
`MYSQL_TYPE_DATETIME'  Datetime
`MYSQL_TYPE_YEAR'      Year
`MYSQL_TYPE_NEWDATE'   Date (MySQL 5.0 or later)
`MYSQL_TYPE_ENUM'      Enumeration
`MYSQL_TYPE_SET'       Set
`MYSQL_TYPE_TINY_BLOB' Tiny Blob
`MYSQL_TYPE_MEDIUM_BLOB'Medium Blob
`MYSQL_TYPE_LONG_BLOB' Long Blob
`MYSQL_TYPE_BLOB'      Blob
`MYSQL_TYPE_VAR_STRING'Varstring
`MYSQL_TYPE_STRING'    String
`MYSQL_TYPE_TINY'      Tiny (compatible with `MYSQL_TYPE_CHAR)'
`MYSQL_TYPE_ENUM'      Enumeration (compatible with
                       `MYSQL_TYPE_INTERVAL')
`MYSQL_TYPE_GEOMETRY'  Geometry
`MYSQL_TYPE_BIT'       Bit


File: manual.info,  Node: mysql-proxy-scripting-connect-server,  Next: mysql-proxy-scripting-read-handshake,  Prev: mysql-proxy-scripting-structures,  Up: mysql-proxy-scripting

15.7.4.3 Capturing a Connection with `connect_server()'
.......................................................

When the proxy accepts a connection from a MySQL client, the
`connect_server()' function is called.

There are no arguments to the function, but you can use and if
necessary manipulate the information in the `proxy.connection' table,
which is unique to each client session.

For example, if you have multiple backend servers, you can specify
which server that connection should use by setting the value of
`proxy.connection.backend_ndx' to a valid server number. The following
code chooses between two servers based on whether the current time in
minutes is odd or even:

     function connect_server()
             print("--> a client really wants to talk to a server")
             if (tonumber(os.date("%M")) % 2 == 0) then
                     proxy.connection.backend_ndx = 2
                     print("Choosing backend 2")
             else
                     proxy.connection.backend_ndx = 1
                     print("Choosing backend 1")
             end
             print("Using " .. proxy.global.backends[proxy.connection.backend_ndx].dst.name)
     end

This example also displays the IP address/port combination by accessing
the information from the internal `proxy.global.backends' table.


File: manual.info,  Node: mysql-proxy-scripting-read-handshake,  Next: mysql-proxy-scripting-read-auth,  Prev: mysql-proxy-scripting-connect-server,  Up: mysql-proxy-scripting

15.7.4.4 Examining the Handshake with `read_handshake()'
........................................................

Handshake information is sent by the server to the client after the
initial connection (through `connect_server()') has been made. The
handshake information contains details about the MySQL version, the ID
of the thread that will handle the connection information, and the IP
address of the client and server. This information is exposed through
the `proxy.connection' structure.

   * `proxy.connection.server.mysqld_version': The version of the MySQL
     server.

   * `proxy.connection.server.thread_id': The thread ID.

   * `proxy.connection.server.scramble_buffer': The password scramble
     buffer.

   * `proxy.connection.server.dst.name': The IP address of the server.

   * `proxy.connection.client.src.name': The IP address of the client.

For example, you can print out the handshake data and refuse clients by
IP address with the following function:

     function read_handshake()
             print("<-- let's send him some information about us")
             print("    mysqld-version: " .. proxy.connection.server.mysqld_version)
             print("    thread-id     : " .. proxy.connection.server.thread_id)
             print("    scramble-buf  : " .. string.format("%q",proxy.connection.server.scramble_buffer))
             print("    server-addr   : " .. proxy.connection.server.dst.name)
             print("    client-addr   : " .. proxy.connection.client.dst.name)

             if not proxy.connection.client.src.name:match("^127.0.0.1:") then
                     proxy.response.type = proxy.MYSQLD_PACKET_ERR
                     proxy.response.errmsg = "only local connects are allowed"

                     print("we don't like this client");

                     return proxy.PROXY_SEND_RESULT
             end
     end

Note that you must return an error packet to the client by using
`proxy.PROXY_SEND_RESULT'.


File: manual.info,  Node: mysql-proxy-scripting-read-auth,  Next: mysql-proxy-scripting-read-auth-result,  Prev: mysql-proxy-scripting-read-handshake,  Up: mysql-proxy-scripting

15.7.4.5 Examining the Authentication Credentials with `read_auth()'
....................................................................

The `read_auth()' function is triggered when an authentication
handshake is initiated by the client. In the execution sequence,
`read_auth()' occurs immediately after `read_handshake()', so the
server selection has already been made, but the connection and
authorization information has not yet been provided to the backend
server.

You can obtain the authentication information by examining the
`proxy.connection.client' structure. For more information, see
`proxy.connection'.

For example, you can print the user name and password supplied during
authorization using:

     function read_auth()
             print("    username      : " .. proxy.connection.client.username)
             print("    password      : " .. string.format("%q", proxy.connection.client.scrambled_password))
     end

You can interrupt the authentication process within this function and
return an error packet back to the client by constructing a new packet
and returning `proxy.PROXY_SEND_RESULT':

     proxy.response.type = proxy.MYSQLD_PACKET_ERR
     proxy.response.errmsg = "Logins are not allowed"
     return proxy.PROXY_SEND_RESULT


File: manual.info,  Node: mysql-proxy-scripting-read-auth-result,  Next: mysql-proxy-scripting-read-query,  Prev: mysql-proxy-scripting-read-auth,  Up: mysql-proxy-scripting

15.7.4.6 Accessing Authentication Information with `read_auth_result()'
.......................................................................

The return packet from the server during authentication is captured by
`read_auth_result()'. The only argument to this function is the
authentication packet returned by the server. As the packet is a raw
MySQL network protocol packet, you must access the first byte to
identify the packet type and contents. The `MYSQLD_PACKET_ERR' and
`MYSQLD_PACKET_OK' constants can be used to identify whether the
authentication was successful:

     function read_auth_result(auth)
             local state = auth.packet:byte()

             if state == proxy.MYSQLD_PACKET_OK then
                     print("<-- auth ok");
             elseif state == proxy.MYSQLD_PACKET_ERR then
                     print("<-- auth failed");
             else
                     print("<-- auth ... don't know: " .. string.format("%q", auth.packet));
             end
     end

If a long-password capable client tries to authenticate to a server
that supports long passwords, but the user password provided is
actually short, `read_auth_result()' will be called twice. The first
time, `auth.packet:byte()' will equal 254, indicating that the client
should try again using the old password protocol. The second time time
`read_auth_result()/' is called, `auth.packet:byte()' will indicate
whether the authentication actually succeeded.


File: manual.info,  Node: mysql-proxy-scripting-read-query,  Next: mysql-proxy-scripting-read-query-result,  Prev: mysql-proxy-scripting-read-auth-result,  Up: mysql-proxy-scripting

15.7.4.7 Manipulating Queries with `read_query()'
.................................................

The `read_query()' function is called once for each query submitted by
the client and accepts a single argument, the query packet that was
provided. To access the content of the packet, you must parse the
packet contents manually.

For example, you can intercept a query packet and print out the
contents using the following function definition:

     function read_query( packet )
             if packet:byte() == proxy.COM_QUERY then
                     print("we got a normal query: " .. packet:sub(2))
             end
     end

This example checks the first byte of the packet to determine the type.
If the type is `COM_QUERY' (see *Note
mysql-proxy-scripting-structures-command-constants::), we extract the
query from the packet and print it. The structure of the packet type
supplied is important. In the case of a `COM_QUERY' packet, the
remaining contents of the packet are the text of the query string. In
this example, no changes have been made to the query or the list of
queries that will ultimately be sent to the MySQL server.

To modify a query, or add new queries, you must populate the query
queue (`proxy.queries'), then execute the queries that you have placed
into the queue. If you do not modify the original query or the queue,
the query received from the client is sent to the MySQL server verbatim.

When adding queries to the queue, you should follow these guidelines:

   * The packets inserted into the queue must be valid query packets.
     For each packet, you must set the initial byte to the packet type.
     If you are appending a query, you can append the query statement
     to the rest of the packet.

   * Once you add a query to the queue, the queue is used as the source
     for queries sent to the server. If you add a query to the queue to
     add more information, you must also add the original query to the
     queue or it will not be executed.

   * Once the queue has been populated, you must set the return value
     from `read_query()' to indicate whether the query queue should be
     sent to the server.

   * When you add queries to the queue, you should add an ID. The ID
     you specify is returned with the result set so that you identify
     each query and corresponding result set. The ID has no other
     purpose than as an identifier for correlating the query and result
     set. When operating in a passive mode, during profiling for
     example, you identify the original query and the corresponding
     result set so that the results expected by the client can be
     returned correctly.

   * Unless your client is designed to cope with more result sets than
     queries, you should ensure that the number of queries from the
     client match the number of results sets returned to the client.
     Using the unique ID and removing result sets you inserted will
     help.

Normally, the `read_query()' and `read_query_result()' function are
used in conjunction with each other to inject additional queries and
remove the additional result sets. However, `read_query_result()' is
only called if you populate the query queue within `read_query()'.


File: manual.info,  Node: mysql-proxy-scripting-read-query-result,  Prev: mysql-proxy-scripting-read-query,  Up: mysql-proxy-scripting

15.7.4.8 Manipulating Results with `read_query_result()'
........................................................

The `read_query_result()' is called for each result set returned by the
server only if you have manually injected queries into the query queue.
If you have not manipulated the query queue, this function is not
called. The function supports a single argument, the result packet,
which provides a number of properties:

   * `id': The ID of the result set, which corresponds to the ID that
     was set when the query packet was submitted to the server when
     using `append(id)' on the query queue. You must have set the
     `resultset_is_needed' flag to `append' to intercept the result set
     before it is returned to the client. See *Note
     mysql-proxy-scripting-structures-queries::.

   * `query': The text of the original query.

   * `query_time': The number of microseconds required to receive the
     first row of a result set since the query was sent to the server.

   * `response_time': The number of microseconds required to receive
     the last row of the result set since the query was sent to the
     server.

   * `resultset': The content of the result set data.

By accessing the result information from the MySQL server, you can
extract the results that match the queries that you injected, return
different result sets (for example, from a modified query), and even
create your own result sets.

The following Lua script, for example, will output the query, followed
by the query time and response time (that is, the time to execute the
query and the time to return the data for the query) for each query
sent to the server:

     function read_query( packet )
             if packet:byte() == proxy.COM_QUERY then
                     print("we got a normal query: " .. packet:sub(2))

                     proxy.queries:append(1, packet )

                     return proxy.PROXY_SEND_QUERY
             end
     end

     function read_query_result(inj)
             print("query-time: " .. (inj.query_time / 1000) .. "ms")
             print("response-time: " .. (inj.response_time / 1000) .. "ms")
     end

You can access the rows of returned results from the result set by
accessing the `rows' property of the `resultset' property of the result
that is exposed through `read_query_result()'. For example, you can
iterate over the results showing the first column from each row using
this Lua fragment:

     for row in inj.resultset.rows do
             print("injected query returned: " .. row[1])
     end

Just like `read_query()', `read_query_result()' can return different
values for each result according to the result returned. If you have
injected additional queries into the query queue, for example, remove
the results returned from those additional queries and return only the
results from the query originally submitted by the client.

The following example injects additional `SELECT NOW()' statements into
the query queue, giving them a different ID to the ID of the original
query. Within `read_query_result()', if the ID for the injected queries
is identified, we display the result row, and return the
`proxy.PROXY_IGNORE_RESULT' from the function so that the result is not
returned to the client. If the result is from any other query, we print
out the query time information for the query and return the default,
which passes on the result set unchanged. We could also have explicitly
returned `proxy.PROXY_IGNORE_RESULT' to the MySQL client.

     function read_query( packet )
             if packet:byte() == proxy.COM_QUERY then
                     proxy.queries:append(2, string.char(proxy.COM_QUERY) .. "SELECT NOW()", {resultset_is_needed = true} )
                     proxy.queries:append(1, packet, {resultset_is_needed = true})
                     proxy.queries:append(2, string.char(proxy.COM_QUERY) .. "SELECT NOW()", {resultset_is_needed = true} )

                     return proxy.PROXY_SEND_QUERY
             end
     end

     function read_query_result(inj)
             if inj.id == 2 then
                     for row in inj.resultset.rows do
                             print("injected query returned: " .. row[1])
                     end
                     return proxy.PROXY_IGNORE_RESULT
             else
                     print("query-time: " .. (inj.query_time / 1000) .. "ms")
                     print("response-time: " .. (inj.response_time / 1000) .. "ms")
             end
     end

For further examples, see *Note mysql-proxy-using::.


File: manual.info,  Node: mysql-proxy-using,  Next: mysql-proxy-faq,  Prev: mysql-proxy-scripting,  Up: mysql-proxy

15.7.5 Using MySQL Proxy
------------------------

* Menu:

* mysql-proxy-using-admin::      Using the Administration Interface

There are a number of different ways to use MySQL Proxy. At the most
basic level, you can allow MySQL Proxy to pass queries from clients to
a single server. To use MySQL Proxy in this mode, you just have to
specify on the command line the backend server to which the proxy
should connect:

     shell> mysql-proxy --proxy-backend-addresses=sakila:3306

If you specify multiple backend MySQL servers, the proxy connects each
client to each server in a round-robin fashion. Suppose that you have
two MySQL servers, A and B. The first client to connect is connected to
server A, the second to server B, the third to server A. For example:

     shell> mysql-proxy \
          --proxy-backend-addresses=narcissus:3306 \
          --proxy-backend-addresses=nostromo:3306

When you specify multiple servers in this way, the proxy automatically
identifies when a MySQL server has become unavailable and marks it
accordingly. New connections are automatically attached to a server
that is available, and a warning is reported to the standard output from
*Note `mysql-proxy': mysql-proxy.:

     network-mysqld.c.367: connect(nostromo:3306) failed: Connection refused
     network-mysqld-proxy.c.2405: connecting to backend (nostromo:3306) failed, marking it as down for ...

Lua scripts enable a finer level of control, both over the connections
and their distribution and how queries and result sets are processed.
When using an Lua script, you must specify the name of the script on
the command line using the `--proxy-lua-script' option:

     shell> mysql-proxy --proxy-lua-script=mc.lua --proxy-backend-addresses=sakila:3306

When you specify a script, the script is not executed until a
connection is made. This means that faults with the script are not
raised until the script is executed. Script faults will not affect the
distribution of queries to backend MySQL servers.

*Note*:

Because a script is not read until the connection is made, you can
modify the contents of the Lua script file while the proxy is still
running and the modified script is automatically used for the next
connection. This ensures that MySQL Proxy remains available because it
need not be restarted for the changes to take effect.


File: manual.info,  Node: mysql-proxy-using-admin,  Prev: mysql-proxy-using,  Up: mysql-proxy-using

15.7.5.1 Using the Administration Interface
...........................................

The *Note `mysql-proxy': mysql-proxy. administration interface can be
accessed using any MySQL client using the standard protocols.  You can
use the administration interface to gain information about the proxy
server as a whole - standard connections to the proxy are isolated to
operate as if you were connected directly to the backend MySQL server.

In *Note `mysql-proxy': mysql-proxy. 0.8.0 and earlier, a rudimentary
interface was built into the proxy. In later versions this was replaced
so that you must specify an administration script to be used when users
connect to the administration interface.

To use the administration interface, you should specify the user name
and password required to connect to the admin service (using the
`--admin-username' and `--admin-password' options). You must also
specify the Lua script to be used as the interface to the
administration service by using the `admin-lua-script' script option to
point to a Lua script.

For example, you can create a basic interface to the internal
components of the *Note `mysql-proxy': mysql-proxy. system using the
following script, written by Diego Medina:

     --[[

        Copyright 2008, 2010, Oracle and/or its affiliates. All rights reserved.

        This program is free software; you can redistribute it and/or modify
        it under the terms of the GNU General Public License as published by
        the Free Software Foundation; version 2 of the License.

        This program is distributed in the hope that it will be useful,
        but WITHOUT ANY WARRANTY; without even the implied warranty of
        MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
        GNU General Public License for more details.

        You should have received a copy of the GNU General Public License
        along with this program; if not, write to the Free Software
        Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA

     --]]

     -- admin.lua

     --[[

         See http://forge.mysql.com/tools/tool.php?id=78
         (Thanks to Jan Kneschke)
         See http://www.chriscalender.com/?p=41
         (Thanks to Chris Calender)
         See http://datacharmer.blogspot.com/2009/01/mysql-proxy-is-back.html
         (Thanks Giuseppe Maxia)

     --]]

     function set_error(errmsg)
         proxy.response = {
             type = proxy.MYSQLD_PACKET_ERR,
             errmsg = errmsg or "error"
         }
     end

     function read_query(packet)
         if packet:byte() ~= proxy.COM_QUERY then
             set_error("[admin] we only handle text-based queries (COM_QUERY)")
             return proxy.PROXY_SEND_RESULT
         end

         local query = packet:sub(2)
         local rows = { }
         local fields = { }

         -- try to match the string up to the first non-alphanum
         local f_s, f_e, command = string.find(packet, "^%s*(%w+)", 2)
         local option

         if f_e then
                 -- if that match, take the next sub-string as option
                 f_s, f_e, option = string.find(packet, "^%s+(%w+)", f_e + 1)
         end

         -- we got our commands, execute it
         if command == "show" and option == "querycounter" then
                 ---
                 -- proxy.PROXY_SEND_RESULT requires
                 --
                 -- proxy.response.type to be either
                 -- * proxy.MYSQLD_PACKET_OK or
                 -- * proxy.MYSQLD_PACKET_ERR
                 --
                 -- for proxy.MYSQLD_PACKET_OK you need a resultset
                 -- * fields
                 -- * rows
                 --
                 -- for proxy.MYSQLD_PACKET_ERR
                 -- * errmsg
                 proxy.response.type = proxy.MYSQLD_PACKET_OK
                 proxy.response.resultset = {
                         fields = {
                                 { type = proxy.MYSQL_TYPE_LONG, name = "query_counter", },
                         },
                         rows = {
                                 { proxy.global.query_counter }
                         }
                 }

                 -- we have our result, send it back
                 return proxy.PROXY_SEND_RESULT
         elseif command == "show" and option == "myerror" then
                 proxy.response.type = proxy.MYSQLD_PACKET_ERR
                 proxy.response.errmsg = "my first error"

                 return proxy.PROXY_SEND_RESULT

         elseif string.sub(packet, 2):lower() == 'select help' then
                 return show_process_help()

         elseif string.sub(packet, 2):lower() == 'show proxy processlist' then
                 return show_process_table()

         elseif query == "SELECT * FROM backends" then
             fields = {
                 { name = "backend_ndx",
                   type = proxy.MYSQL_TYPE_LONG },

                 { name = "address",
                   type = proxy.MYSQL_TYPE_STRING },
                 { name = "state",
                   type = proxy.MYSQL_TYPE_STRING },
                 { name = "type",
                   type = proxy.MYSQL_TYPE_STRING },
             }

             for i = 1, #proxy.global.backends do
                 local b = proxy.global.backends[i]

                 rows[#rows + 1] = {
                     i, b.dst.name, b.state, b.type
                 }
             end
         else
             set_error()
             return proxy.PROXY_SEND_RESULT
         end

         proxy.response = {
             type = proxy.MYSQLD_PACKET_OK,
             resultset = {
                 fields = fields,
                 rows = rows
             }
         }
         return proxy.PROXY_SEND_RESULT
     end

     function make_dataset (header, dataset)
         proxy.response.type = proxy.MYSQLD_PACKET_OK

         proxy.response.resultset = {
             fields = {},
             rows = {}
         }
         for i,v in pairs (header) do
             table.insert(proxy.response.resultset.fields, {type = proxy.MYSQL_TYPE_STRING, name = v})
         end
         for i,v in pairs (dataset) do
             table.insert(proxy.response.resultset.rows, v )
         end
         return proxy.PROXY_SEND_RESULT
     end

     function show_process_table()
         local dataset = {}
         local header = { 'Id', 'IP Address', 'Time' }
         local rows = {}
         for t_i, t_v in pairs (proxy.global.process) do
             for s_i, s_v in pairs ( t_v ) do
                 table.insert(rows, { t_i, s_v.ip, os.date('%c',s_v.ts) })
             end
         end
         return make_dataset(header,rows)
     end

     function show_process_help()
         local dataset = {}
         local header = { 'command',  'description' }
         local rows = {
             {'SELECT HELP',                 'This command.'},
             {'SHOW PROXY PROCESSLIST',      'Show all connections and their true IP Address.'},
         }
         return make_dataset(header,rows)
     end

     function dump_process_table()
         proxy.global.initialize_process_table()
         print('current contents of process table')
         for t_i, t_v in pairs (proxy.global.process) do
             print ('session id: ', t_i)
             for s_i, s_v in pairs ( t_v ) do
                 print ( '\t', s_i, s_v.ip, s_v.ts )
             end
         end
         print ('---END PROCESS TABLE---')
     end

     --[[    Help

     we use a simple string-match to split commands are word-boundaries

     mysql> show querycounter

     is split into
     command = "show"
     option  = "querycounter"

     spaces are ignored, the case has to be as is.

     mysql> show myerror

     returns a error-packet

     --]]

The script works in combination with a main proxy script,
`reporter.lua':

     --[[

        Copyright 2008, 2010, Oracle and/or its affiliates. All rights reserved.

        This program is free software; you can redistribute it and/or modify
        it under the terms of the GNU General Public License as published by
        the Free Software Foundation; version 2 of the License.

        This program is distributed in the hope that it will be useful,
        but WITHOUT ANY WARRANTY; without even the implied warranty of
        MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
        GNU General Public License for more details.

        You should have received a copy of the GNU General Public License
        along with this program; if not, write to the Free Software
        Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA

     --]]

     -- reporter.lua

     --[[

         See http://forge.mysql.com/tools/tool.php?id=78
         (Thanks to Jan Kneschke)
         See http://www.chriscalender.com/?p=41
         (Thanks to Chris Calender)
         See http://datacharmer.blogspot.com/2009/01/mysql-proxy-is-back.html
         (Thanks Giuseppe Maxia)

     --]]

     proxy.global.query_counter = proxy.global.query_counter or 0

     function proxy.global.initialize_process_table()
         if proxy.global.process == nil then
             proxy.global.process = {}
         end
         if proxy.global.process[proxy.connection.server.thread_id] == nil then
             proxy.global.process[proxy.connection.server.thread_id] = {}
         end
     end

     function read_auth_result( auth )
         local state = auth.packet:byte()
         if state == proxy.MYSQLD_PACKET_OK then
             proxy.global.initialize_process_table()
             table.insert( proxy.global.process[proxy.connection.server.thread_id],
                 { ip = proxy.connection.client.src.name, ts = os.time() } )
         end
     end

     function disconnect_client()
         local connection_id = proxy.connection.server.thread_id
         if connection_id then
             -- client has disconnected, set this to nil
             proxy.global.process[connection_id] = nil
         end
     end

     ---
     -- read_query() can return a resultset
     --
     -- You can use read_query() to return a result-set.
     --
     -- @param packet the mysql-packet sent by the client
     --
     -- @return
     --   * nothing to pass on the packet as is,
     --   * proxy.PROXY_SEND_QUERY to send the queries from the proxy.queries queue
     --   * proxy.PROXY_SEND_RESULT to send your own result-set
     --
     function read_query( packet )
             -- a new query came in in this connection
             -- using proxy.global.* to make it available to the admin plugin
             proxy.global.query_counter = proxy.global.query_counter + 1

     end

To use the script, save the first script to a file (`admin.lua' in the
following example) and the other to `reporter.lua', then run *Note
`mysql-proxy': mysql-proxy. specifying the admin script and a backend
MySQL server:

     shell> mysql-proxy --admin-lua-script=admin.lua --admin-password=password \ »
          --admin-username=root --proxy-backend-addresses=127.0.0.1:3306 -proxy-lua-script=reporter.lua

In a different window, connect to the MySQL server through the proxy:

     shell> mysql --user=root --password=password --port=4040
     Welcome to the MySQL monitor.  Commands end with ; or \g.
     Your MySQL connection id is 1798669
     Server version: 5.0.70-log Gentoo Linux mysql-5.0.70-r1

     Type 'help;' or '\h' for help. Type '\c' to clear the buffer.

     mysql>

In another different window, connect to the *Note `mysql-proxy':
mysql-proxy. admin service using the specified user name and password:

     shell> mysql --user=root --password=password --port=4041 --host=localhost
     Welcome to the MySQL monitor.  Commands end with ; or \g.
     Your MySQL connection id is 1
     Server version: 5.0.99-agent-admin

     Type 'help;' or '\h' for help. Type '\c' to clear the buffer.

     mysql>

To monitor the status of the proxy, ask for a list of the current
active processes:

     mysql> show proxy processlist;
     +---------+---------------------+--------------------------+
     | Id      | IP Address          | Time                     |
     +---------+---------------------+--------------------------+
     | 1798669 | 192.168.0.112:52592 | Wed Jan 20 16:58:00 2010 |
     +---------+---------------------+--------------------------+
     1 row in set (0.00 sec)

     mysql>

For more information on the example, see MySQL Proxy Admin Example
(http://fmpwizard.blogspot.com/2009/04/how-do-i-use-mysql-proxy-admin-plugin.html).


File: manual.info,  Node: mysql-proxy-faq,  Prev: mysql-proxy-using,  Up: mysql-proxy

15.7.6 MySQL Proxy FAQ
----------------------

*Questions*
   * 15.7.6.1: In load balancing, how can I separate reads from writes?

   * 15.7.6.2: How do I use a socket with MySQL Proxy? Proxy change logs
     mention that support for UNIX sockets has been added.

   * 15.7.6.3: Can I use MySQL Proxy with all versions of MySQL?

   * 15.7.6.4: Can I run MySQL Proxy as a daemon?

   * 15.7.6.5: Will the proxy road map involve moving popular features
     from Lua to C? (For example, Read/Write splitting.)

   * 15.7.6.6: Do proxy applications run on a separate server? If not,
     what is the overhead incurred by Proxy on the DB server side?

   * 15.7.6.7: With load balancing, what happens to transactions? Are
     all queries sent to the same server?

   * 15.7.6.8: We have looked at using MySQL Proxy but we are concerned
     about the alpha status. When do you think the proxy will be
     considered production ready?

   * 15.7.6.9: Is it possible to use MySQL Proxy with updating a Lucene
     index (or Solr) by making TCP calls to that server to update?

   * 15.7.6.10: Is the system context switch expensive, how much
     overhead does the Lua script add?

   * 15.7.6.11: How much latency does a proxy add to a connection?

   * 15.7.6.12: Do you have to make one large script and call it at
     proxy startup, can I change scripts without stopping and restarting
     (interrupting) the proxy?

   * 15.7.6.13: If MySQL Proxy has to live on same machine as MySQL,
     are there any tuning considerations to ensure both perform
     optimally?

   * 15.7.6.14: Can MySQL Proxy be used on slaves and intercept binary
     log messages?

   * 15.7.6.15: I currently use SQL Relay for efficient connection
     pooling with a number of Apache processes connecting to a MySQL
     server. Can MySQL Proxy currently accomplish this? My goal is to
     minimize connection latency while keeping temporary tables
     available.

   * 15.7.6.16: Are these reserved function names (for example,
     `error_result()') that get automatically called?

   * 15.7.6.17: As the script is re-read by MySQL Proxy, does it cache
     this or is it looking at the file system with each request?

   * 15.7.6.18: Given that there is a `connect_server()' function, can
     a Lua script link up with multiple servers?

   * 15.7.6.19: Is the MySQL Proxy an API?

   * 15.7.6.20: The global namespace variable example with quotas does
     not persist after a reboot, is that correct?

   * 15.7.6.21: Can MySQL Proxy handle SSL connections?

   * 15.7.6.22: Could MySQL Proxy be used to capture passwords?

   * 15.7.6.23: Are there tools for isolating problems? How can someone
     figure out whether a problem is in the client, the database, or the
     proxy?

   * 15.7.6.24: Can you explain the status of your work with
     `memcached' and MySQL Proxy?

   * 15.7.6.25: Is MySQL Proxy similar to what is provided by Java
     connection pools?

   * 15.7.6.26: So authentication with connection pooling has to be
     done at every connection? What is the authentication latency?

   * 15.7.6.27: If you have multiple databases on the same box, can you
     use proxy to connect to databases on default port 3306?

   * 15.7.6.28: What about caching the authorization information so
     clients connecting are given back-end connections that were
     established with identical authorization information, thus saving
     a few more round trips?

   * 15.7.6.29: Is there any big web site using MySQL Proxy? For what
     purpose and what transaction rate have they achieved?

   * 15.7.6.30: How does MySQL Proxy compare to DBSlayer?

   * 15.7.6.31: I tried using MySQL Proxy without any Lua script to try
     a round-robin type load balancing. In this case, if the first
     database in the list is down, MySQL Proxy would not connect the
     client to the second database in the list.

   * 15.7.6.32: Is it `safe' to use `LuaSocket' with proxy scripts?

   * 15.7.6.33: How different is MySQL Proxy from DBCP (Database
     connection pooling) for Apache in terms of connection pooling?

   * 15.7.6.34: MySQL Proxy can handle about 5000 connections, what is
     the limit on a MySQL server?

   * 15.7.6.35: Would the Java-only connection pooling solution work for
     multiple web servers? With this, I would assume that you can pool
     across many web servers at once?

   * 15.7.6.36: Can you dynamically reconfigure the pool of MySQL
     servers that MySQL Proxy will use for load balancing?

   * 15.7.6.37: In the quick poll, I see "Load Balancer: read-write
     splitting" as an option, so would it be correct to say that there
     are no scripts written for Proxy yet to do this?

*Questions and Answers* *15.7.6.1: ** In load balancing, how can I
separate reads from writes?  *

There is no automatic separation of queries that perform reads or
writes to the different backend servers. However, you can specify to
*Note `mysql-proxy': mysql-proxy. that one or more of the `backend'
MySQL servers are read only.

     shell> mysql-proxy \
     --proxy-backend-addresses=10.0.1.2:3306 \
     --proxy-read-only-backend-addresses=10.0.1.3:3306 &

*15.7.6.2: ** How do I use a socket with MySQL Proxy? Proxy change logs
mention that support for UNIX sockets has been added.  *

Specify the path to the socket:

     --proxy-backend-addresses=/PATH/TO/SOCKET

*15.7.6.3: ** Can I use MySQL Proxy with all versions of MySQL?  *

MySQL Proxy is designed to work with MySQL 5.0 or higher, and supports
the MySQL network protocol for 5.0 and higher.

*15.7.6.4: ** Can I run MySQL Proxy as a daemon?  *

Use the `--daemon' option. To keep track of the process ID, the daemon
can be started with the `--pid-file=file' option to save the PID to a
known file name. On version 0.5.x, the Proxy cannot be started natively
as a daemon.

*15.7.6.5: ** Will the proxy road map involve moving popular features
from Lua to C? (For example, Read/Write splitting.)  *

We will keep the high-level parts in the Lua layer to be able to adjust
to special situations without a rebuild. Read/Write splitting sometimes
needs external knowledge that may only be available by the DBA.

*15.7.6.6: ** Do proxy applications run on a separate server? If not,
what is the overhead incurred by Proxy on the DB server side?  *

You can run the proxy on the application server, on its own box, or on
the DB-server depending on the use case.

*15.7.6.7: ** With load balancing, what happens to transactions? Are all
queries sent to the same server?  *

Without any special customization the whole connection is sent to the
same server. That keeps the whole connection state intact.

*15.7.6.8: ** We have looked at using MySQL Proxy but we are concerned
about the alpha status. When do you think the proxy will be considered
production ready?  *

We are on the road to the next feature release: 0.9.0. It will improve
the performance quite a bit. After that we may be able to enter the
beta phase.

*15.7.6.9: ** Is it possible to use MySQL Proxy with updating a Lucene
index (or Solr) by making TCP calls to that server to update?  *

Yes, but it is not advised for now.

*15.7.6.10: ** Is the system context switch expensive, how much
overhead does the Lua script add?  *

Lua is fast and the overhead should be small enough for most
applications. The raw packet overhead is around 400 microseconds.

*15.7.6.11: ** How much latency does a proxy add to a connection?  *

In the range of 400 microseconds per request.

*15.7.6.12: ** Do you have to make one large script and call it at proxy
startup, can I change scripts without stopping and restarting
(interrupting) the proxy?  *

You can just change the script and the proxy will reload it when a
client connects.

*15.7.6.13: ** If MySQL Proxy has to live on same machine as MySQL, are
there any tuning considerations to ensure both perform optimally?  *

MySQL Proxy can live on any box: application, database, or its own box.
MySQL Proxy uses comparatively little CPU or RAM, with negligible
additional requirements or overhead.

*15.7.6.14: ** Can MySQL Proxy be used on slaves and intercept binary
log messages?  *

We are working on that. See
`http://jan.kneschke.de/2008/5/30/mysql-proxy-rbr-to-sbr-decoding' for
an example.

*15.7.6.15: ** I currently use SQL Relay for efficient connection
pooling with a number of Apache processes connecting to a MySQL server.
Can MySQL Proxy currently accomplish this? My goal is to minimize
connection latency while keeping temporary tables available.  *

Yes.

*15.7.6.16: ** Are these reserved function names (for example,
`error_result()') that get automatically called?  *

Only functions and values starting with `proxy.*' are provided by the
proxy. All others are user provided.

*15.7.6.17: ** As the script is re-read by MySQL Proxy, does it cache
this or is it looking at the file system with each request?  *

It looks for the script at client-connect and reads it if it has
changed, otherwise it uses the cached version.

*15.7.6.18: ** Given that there is a `connect_server()' function, can a
Lua script link up with multiple servers?  *

MySQL Proxy provides some tutorials in the source package; one is
`examples/tutorial-keepalive.lua'.

*15.7.6.19: ** Is the MySQL Proxy an API?  *

No, MySQL Proxy is an application that forwards packets from a client
to a server using the MySQL network protocol. The MySQL Proxy provides
a API allowing you to change its behavior.

*15.7.6.20: ** The global namespace variable example with quotas does
not persist after a reboot, is that correct?  *

Yes. If you restart the proxy, you lose the results, unless you save
them in a file.

*15.7.6.21: ** Can MySQL Proxy handle SSL connections?  *

No, being the man-in-the-middle, Proxy cannot handle encrypted sessions
because it cannot share the SSL information.

*15.7.6.22: ** Could MySQL Proxy be used to capture passwords?  *

The MySQL network protocol does not allow passwords to be sent in
cleartext, all you could capture is the encrypted version.

*15.7.6.23: ** Are there tools for isolating problems? How can someone
figure out whether a problem is in the client, the database, or the
proxy?  *

You can set a debug script in the proxy, which is an exceptionally good
tool for this purpose. You can see very clearly which component is
causing the problem, if you set the right breakpoints.

*15.7.6.24: ** Can you explain the status of your work with `memcached'
and MySQL Proxy?  *

There are some ideas to integrate proxy and `memcache' a bit, but no
code yet.

*15.7.6.25: ** Is MySQL Proxy similar to what is provided by Java
connection pools?  *

Yes and no. Java connection pools are specific to Java applications,
MySQL Proxy works with any client API that talks the MySQL network
protocol. Also, connection pools do not provide any functionality for
intelligently examining the network packets and modifying the contents.

*15.7.6.26: ** So authentication with connection pooling has to be done
at every connection? What is the authentication latency?  *

You can skip the round-trip and use the connection as it was added to
the pool. As long as the application cleans up the temporary tables it
used. The overhead is (as always) around 400 microseconds.

*15.7.6.27: ** If you have multiple databases on the same box, can you
use proxy to connect to databases on default port 3306?  *

Yes, MySQL Proxy can listen on any port, provided that none of the
MySQL servers are listening on the same port.

*15.7.6.28: ** What about caching the authorization information so
clients connecting are given back-end connections that were established
with identical authorization information, thus saving a few more round
trips?  *

There is an `--proxy-pool-no-change-user' option that provides this
functionality.

*15.7.6.29: ** Is there any big web site using MySQL Proxy? For what
purpose and what transaction rate have they achieved?  *

Yes, gaiaonline (http://gaiaonline.com/).  They have tested MySQL Proxy
and seen it handle 2400 queries per second through the proxy.

*15.7.6.30: ** How does MySQL Proxy compare to DBSlayer?  *

DBSlayer is a REST->MySQL tool, MySQL Proxy is transparent to your
application. No change to the application is needed.

*15.7.6.31: ** I tried using MySQL Proxy without any Lua script to try a
round-robin type load balancing. In this case, if the first database in
the list is down, MySQL Proxy would not connect the client to the
second database in the list.  *

This issue is fixed in version 0.7.0.

*15.7.6.32: ** Is it `safe' to use `LuaSocket' with proxy scripts?  *

You can, but it is not advised because it may block.

*15.7.6.33: ** How different is MySQL Proxy from DBCP (Database
connection pooling) for Apache in terms of connection pooling?  *

Connection Pooling is just one use case of the MySQL Proxy. You can use
it for a lot more and it works in cases where you cannot use DBCP (for
example, if you do not have Java).

*15.7.6.34: ** MySQL Proxy can handle about 5000 connections, what is
the limit on a MySQL server?  *

The server limit is given by the value of the `max_connections' system
variable. The default value is version dependent.

*15.7.6.35: ** Would the Java-only connection pooling solution work for
multiple web servers? With this, I would assume that you can pool
across many web servers at once?  *

Yes. But you can also start one proxy on each application server to get
a similar behavior as you have it already.

*15.7.6.36: ** Can you dynamically reconfigure the pool of MySQL
servers that MySQL Proxy will use for load balancing?  *

Not yet, it is on the list. We are working on a administration
interface for that purpose.

*15.7.6.37: ** In the quick poll, I see "Load Balancer: read-write
splitting" as an option, so would it be correct to say that there are no
scripts written for Proxy yet to do this?  *

There is a proof of concept script for that included. But its far from
perfect and may not work for you yet.


File: manual.info,  Node: replication,  Next: mysql-cluster,  Prev: ha-overview,  Up: Top

16 Replication
**************

* Menu:

* replication-configuration::    Replication Configuration
* replication-implementation::   Replication Implementation
* replication-solutions::        Replication Solutions
* replication-notes::            Replication Notes and Tips

Replication enables data from one MySQL database server (the master) to
be replicated to one or more MySQL database servers (the slaves).
Replication is asynchronous - slaves need not be connected permanently
to receive updates from the master. This means that updates can occur
over long-distance connections and even over temporary or intermittent
connections such as a dial-up service.  Depending on the configuration,
you can replicate all databases, selected databases, or even selected
tables within a database.

The target uses for replication in MySQL include:

   * Scale-out solutions - spreading the load among multiple slaves to
     improve performance. In this environment, all writes and updates
     must take place on the master server. Reads, however, may take
     place on one or more slaves. This model can improve the
     performance of writes (since the master is dedicated to updates),
     while dramatically increasing read speed across an increasing
     number of slaves.

   * Data security - because data is replicated to the slave, and the
     slave can pause the replication process, it is possible to run
     backup services on the slave without corrupting the corresponding
     master data.

   * Analytics - live data can be created on the master, while the
     analysis of the information can take place on the slave without
     affecting the performance of the master.

   * Long-distance data distribution - if a branch office would like to
     work with a copy of your main data, you can use replication to
     create a local copy of the data for their use without requiring
     permanent access to the master.

Replication in MySQL features support for one-way, asynchronous
replication, in which one server acts as the master, while one or more
other servers act as slaves. This is in contrast to the _synchronous_
replication which is a characteristic of MySQL Cluster (see *Note
mysql-cluster::).

There are a number of solutions available for setting up replication
between two servers, but the best method to use depends on the presence
of data and the engine types you are using. For more information on the
available options, see *Note replication-howto::.

Replication is controlled through a number of different options and
variables. These control the core operation of the replication,
timeouts, and the databases and filters that can be applied on
databases and tables. For more information on the available options,
see *Note replication-options::.

You can use replication to solve a number of different problems,
including problems with performance, supporting the backup of different
databases, and as part of a larger solution to alleviate system
failures. For information on how to address these issues, see *Note
replication-solutions::.

For notes and tips on how different data types and statements are
treated during replication, including details of replication features,
version compatibility, upgrades, and problems and their resolution,
including an FAQ, see *Note replication-notes::.

For detailed information on the implementation of replication, how
replication works, the process and contents of the binary log,
background threads and the rules used to decide how statements are
recorded and replication, see *Note replication-implementation::.


File: manual.info,  Node: replication-configuration,  Next: replication-implementation,  Prev: replication,  Up: replication

16.1 Replication Configuration
==============================

* Menu:

* replication-howto::            How to Set Up Replication
* replication-options::          Replication and Binary Logging Options and Variables
* replication-administration::   Common Replication Administration Tasks

Replication between servers in MySQL is based on the binary logging
mechanism. The MySQL instance operating as the master (the source of
the database changes) writes updates and changes as `events' to the
binary log. The information in the binary log is stored in different
logging formats according to the database changes being recorded.
Slaves are configured to read the binary log from the master and to
execute the events in the binary log on the slave's local database.

The master is `dumb' in this scenario. Once binary logging has been
enabled, all statements are recorded in the binary log. Each slave
receives a copy of the entire contents of the binary log. It is the
responsibility of the slave to decide which statements in the binary
log should be executed; you cannot configure the master to log only
certain events. If you do not specify otherwise, all events in the
master binary log are executed on the slave. If required, you can
configure the slave to process only events that apply to particular
databases or tables.

Each slave keeps a record of the binary log coordinates: The file name
and position within the file that it has read and processed from the
master. This means that multiple slaves can be connected to the master
and executing different parts of the same binary log.  Because the
slaves control this process, individual slaves can be connected and
disconnected from the server without affecting the master's operation.
Also, because each slave remembers the position within the binary log,
it is possible for slaves to be disconnected, reconnect and then `catch
up' by continuing from the recorded position.

Both the master and each slave must be configured with a unique ID
(using the `server-id' option). In addition, each slave must be
configured with information about the master host name, log file name,
and position within that file.  These details can be controlled from
within a MySQL session using the *Note `CHANGE MASTER TO':
change-master-to. statement on the slave. The details are stored within
the slave's `master.info' file.

This section describes the setup and configuration required for a
replication environment, including step-by-step instructions for
creating a new replication environment. The major components of this
section are:

   * For a guide to setting up two or more servers for replication,
     *Note replication-howto::, deals with the configuration of the
     systems and provides methods for copying data between the master
     and slaves.

   * Detailed information on the different configuration options and
     variables that apply to replication is provided in *Note
     replication-options::.

   * Once started, the replication process should require little
     administration or monitoring. However, for advice on common tasks
     that you may want to execute, see *Note
     replication-administration::.


File: manual.info,  Node: replication-howto,  Next: replication-options,  Prev: replication-configuration,  Up: replication-configuration

16.1.1 How to Set Up Replication
--------------------------------

* Menu:

* replication-howto-masterbaseconfig::  Setting the Replication Master Configuration
* replication-howto-slavebaseconfig::  Setting the Replication Slave Configuration
* replication-howto-repuser::    Creating a User for Replication
* replication-howto-masterstatus::  Obtaining the Replication Master Binary Log Coordinates
* replication-howto-mysqldump::  Creating a Data Snapshot Using `mysqldump'
* replication-howto-rawdata::    Creating a Data Snapshot Using Raw Data Files
* replication-howto-newservers::  Setting Up Replication with New Master and Slaves
* replication-howto-existingdata::  Setting Up Replication with Existing Data
* replication-howto-additionalslaves::  Introducing Additional Slaves to an Existing Replication Environment
* replication-howto-slaveinit::  Setting the Master Configuration on the Slave

This section describes how to set up complete replication of a MySQL
server. There are a number of different methods for setting up
replication, and the exact method to use depends on how you are setting
up replication, and whether you already have data within your master
database.

There are some generic tasks that are common to all replication setups:

   * On the master, you must enable binary logging and configure a
     unique server ID. This might require a server restart. See *Note
     replication-howto-masterbaseconfig::.

   * On each slave that you want to connect to the master, you must
     configure a unique server ID. This might require a server restart.
     See *Note replication-howto-slavebaseconfig::.

   * You may want to create a separate user that will be used by your
     slaves to authenticate with the master to read the binary log for
     replication. The step is optional. See *Note
     replication-howto-repuser::.

   * Before creating a data snapshot or starting the replication
     process, you should record the position of the binary log on the
     master. You will need this information when configuring the slave
     so that the slave knows where within the binary log to start
     executing events. See *Note replication-howto-masterstatus::.

   * If you already have data on your master and you want to use it to
     synchronize your slave, you will need to create a data snapshot.
     You can create a snapshot using *Note `mysqldump': mysqldump. (see
     *Note replication-howto-mysqldump::) or by copying the data files
     directly (see *Note replication-howto-rawdata::).

   * You will need to configure the slave with settings for connecting
     to the master, such as the host name, login credentials, and
     binary log file name and position. See *Note
     replication-howto-slaveinit::.

Once you have configured the basic options, you will need to follow the
instructions for your replication setup. A number of alternatives are
provided:

   * If you are establishing a new MySQL master and one or more slaves,
     you need only set up the configuration, as you have no data to
     exchange. For guidance on setting up replication in this
     situation, see *Note replication-howto-newservers::.

   * If you are already running a MySQL server, and therefore already
     have data that must be transferred to your slaves before
     replication starts, have not previously configured the binary log
     and are able to shut down your MySQL server for a short period
     during the process, see *Note replication-howto-existingdata::.

   * If you are adding slaves to an existing replication environment,
     you can set up the slaves without affecting the master. See *Note
     replication-howto-additionalslaves::.

If you will be administering MySQL replication servers, we suggest that
you read this entire chapter through and try all statements mentioned
in *Note replication-master-sql::, and *Note replication-slave-sql::.
You should also familiarize yourself with the replication startup
options described in *Note replication-options::.

*Note*:

Note that certain steps within the setup process require the `SUPER'
privilege. If you do not have this privilege, it might not be possible
to enable replication.


File: manual.info,  Node: replication-howto-masterbaseconfig,  Next: replication-howto-slavebaseconfig,  Prev: replication-howto,  Up: replication-howto

16.1.1.1 Setting the Replication Master Configuration
.....................................................

On a replication master, you must enable binary logging and establish a
unique server ID. If this has not already been done, this part of
master setup requires a server restart.

Binary logging _must_ be enabled on the master because the binary log
is the basis for sending data changes from the master to its slaves. If
binary logging is not enabled, replication will not be possible.

Each server within a replication group must be configured with a unique
server ID. This ID is used to identify individual servers within the
group, and must be a positive integer between 1 and (2^32)-1. How you
organize and select the numbers is entirely up to you.

To configure the binary log and server ID options, you will need to
shut down your MySQL server and edit the `my.cnf' or `my.ini' file.
Add the following options to the configuration file within the
`[mysqld]' section. If these options already exist, but are commented
out, uncomment the options and alter them according to your needs. For
example, to enable binary logging using a log file name prefix of
`mysql-bin', and configure a server ID of 1, use these lines:

     [mysqld]
     log-bin=mysql-bin
     server-id=1

After making the changes, restart the server.

*Note*:

If you omit `server-id' (or set it explicitly to its default value of
0), a master refuses connections from all slaves.

*Note*:

For the greatest possible durability and consistency in a replication
setup using `InnoDB' with transactions, you should use
`innodb_flush_log_at_trx_commit=1' and `sync_binlog=1' in the master
`my.cnf' file.

*Note*:

Ensure that the `skip-networking' option is not enabled on your
replication master. If networking has been disabled, your slave will
not able to communicate with the master and replication will fail.


File: manual.info,  Node: replication-howto-slavebaseconfig,  Next: replication-howto-repuser,  Prev: replication-howto-masterbaseconfig,  Up: replication-howto

16.1.1.2 Setting the Replication Slave Configuration
....................................................

On a replication slave, you must establish a unique server ID.  If this
has not already been done, this part of slave setup requires a server
restart.

If the slave server ID is not already set, or the current value
conflicts with the value that you have chosen for the master server,
you should shut down your slave server and edit the configuration to
specify a unique server ID. For example:

     [mysqld]
     server-id=2

After making the changes, restart the server.

If you are setting up multiple slaves, each one must have a unique
`server-id' value that differs from that of the master and from each of
the other slaves. Think of `server-id' values as something similar to
IP addresses: These IDs uniquely identify each server instance in the
community of replication partners.

*Note*:

If you omit `server-id' (or set it explicitly to its default value of
0), a slave refuses to connect to a master.

You do not have to enable binary logging on the slave for replication
to be enabled. However, if you enable binary logging on the slave, you
can use the binary log for data backups and crash recovery on the
slave, and also use the slave as part of a more complex replication
topology (for example, where the slave acts as a master to other
slaves).


File: manual.info,  Node: replication-howto-repuser,  Next: replication-howto-masterstatus,  Prev: replication-howto-slavebaseconfig,  Up: replication-howto

16.1.1.3 Creating a User for Replication
........................................

Each slave must connect to the master using a MySQL user name and
password, so there must be a user account on the master that the slave
can use to connect. Any account can be used for this operation,
providing it has been granted the `REPLICATION SLAVE' privilege. You
may wish to create a different account for each slave, or connect to
the master using the same account for each slave.

You need not create an account specifically for replication.  However,
you should be aware that the user name and password will be stored in
plain text within the `master.info' file (see *Note
slave-logs-status::). Therefore, you may want to create a separate
account that has privileges only for the replication process, to
minimize the possibility of compromise to other accounts.

To create a new acccount, use *Note `CREATE USER': create-user. To
grant this account the privileges required for replication, use the
*Note `GRANT': grant.  statement. If you create an account solely for
the purposes of replication, that account needs only the `REPLICATION
SLAVE' privilege. For example, to set up a new user, `repl', that can
connect for replication from any host within the `mydomain.com' domain,
issue these statements on the master:

     mysql> CREATE USER 'repl'@'%.mydomain.com' IDENTIFIED BY 'slavepass';
     mysql> GRANT REPLICATION SLAVE ON *.* TO 'repl'@'%.mydomain.com';

See *Note account-management-sql::, for more information on statements
for manipulation of user accounts.


File: manual.info,  Node: replication-howto-masterstatus,  Next: replication-howto-mysqldump,  Prev: replication-howto-repuser,  Up: replication-howto

16.1.1.4 Obtaining the Replication Master Binary Log Coordinates
................................................................

To configure replication on the slave you must determine the master's
current coordinates within its binary log. You will need this
information so that when the slave starts the replication process, it
is able to start processing events from the binary log at the correct
point.

If you have existing data on your master that you want to synchronize
on your slaves before starting the replication process, you must stop
processing statements on the master, and then obtain its current binary
log coordinates and dump its data, before permitting the master to
continue executing statements. If you do not stop the execution of
statements, the data dump and the master status information that you
use will not match and you will end up with inconsistent or corrupted
databases on the slaves.

To obtain the master binary log coordinates, follow these steps:

  1. Start a session on the master by connecting to it with the
     command-line client, and flush all tables and block write
     statements by executing the *Note `FLUSH TABLES WITH READ LOCK':
     flush. statement:

          mysql> FLUSH TABLES WITH READ LOCK;

     For `InnoDB' tables, note that *Note `FLUSH TABLES WITH READ
     LOCK': flush. also blocks *Note `COMMIT': commit. operations.

     *Warning*:

     Leave the client from which you issued the *Note `FLUSH TABLES':
     flush. statement running so that the read lock remains in effect.
     If you exit the client, the lock is released.

  2. In a different session on the master, use the *Note `SHOW MASTER
     STATUS': show-master-status. statement to determine the current
     binary log file name and position:

          mysql > SHOW MASTER STATUS;
          +------------------+----------+--------------+------------------+
          | File             | Position | Binlog_Do_DB | Binlog_Ignore_DB |
          +------------------+----------+--------------+------------------+
          | mysql-bin.000003 | 73       | test         | manual,mysql     |
          +------------------+----------+--------------+------------------+

     The `File' column shows the name of the log file and `Position'
     shows the position within the file. In this example, the binary
     log file is `mysql-bin.000003' and the position is 73.  Record
     these values. You need them later when you are setting up the
     slave. They represent the replication coordinates at which the
     slave should begin processing new updates from the master.

     If the master has been running previously without binary logging
     enabled, the log file name and position values displayed by *Note
     `SHOW MASTER STATUS': show-master-status. or *Note `mysqldump
     --master-data': mysqldump. will be empty. In that case, the values
     that you need to use later when specifying the slave's log file
     and position are the empty string (`''') and `4'.

You now have the information you need to enable the slave to start
reading from the binary log in the correct place to start replication.

If you have existing data that needs be to synchronized with the slave
before you start replication, leave the client running so that the lock
remains in place and then proceed to *Note
replication-howto-mysqldump::, or *Note replication-howto-rawdata::.
The idea here is to prevent any further changes so that the data copied
to the slaves is in synchrony with the master.

If you are setting up a brand new master and slave replication group,
you can exit the first session to release the read lock.


File: manual.info,  Node: replication-howto-mysqldump,  Next: replication-howto-rawdata,  Prev: replication-howto-masterstatus,  Up: replication-howto

16.1.1.5 Creating a Data Snapshot Using `mysqldump'
...................................................

One way to create a snapshot of the data in an existing master database
is to use the *Note `mysqldump': mysqldump. tool. Once the data dump
has been completed, you then import this data into the slave before
starting the replication process.

To obtain a snapshot of the data using *Note `mysqldump': mysqldump.:

  1. If you have not already locked the tables on the server to prevent
     statements that update data from executing:

     Start a session on the server by connecting to it with the
     command-line client, and flush all tables and block write
     statements by executing the *Note `FLUSH TABLES WITH READ LOCK':
     flush. statement:

          mysql> FLUSH TABLES WITH READ LOCK;

     Remember to use *Note `SHOW MASTER STATUS': show-master-status.
     and record the binary log details for use when starting up the
     slave. The point in time of your snapshot and the binary log
     position must match. See *Note replication-howto-masterstatus::.

  2. In another session, use *Note `mysqldump': mysqldump. to create a
     dump either of all the databases you want to replicate, or of
     selected individual databases. For example:

          shell> mysqldump --all-databases --lock-all-tables >dbdump.db

     An alternative to using a bare dump, is to use the `--master-data'
     option, which automatically appends the *Note `CHANGE MASTER TO':
     change-master-to.  statement required on the slave to start the
     replication process.

          shell> mysqldump --all-databases --master-data >dbdump.db

  3. In the client where you acquired the read lock, release the lock:

          mysql> UNLOCK TABLES;

     Alternatively, exit the first session to release the read lock.

When choosing databases to include in the dump, remember that you will
need to filter out databases on each slave that you do not want to
include in the replication process.

You will need either to copy the dump file to the slave, or to use the
file from the master when connecting remotely to the slave to import
the data.


File: manual.info,  Node: replication-howto-rawdata,  Next: replication-howto-newservers,  Prev: replication-howto-mysqldump,  Up: replication-howto

16.1.1.6 Creating a Data Snapshot Using Raw Data Files
......................................................

If your database is particularly large, copying the raw data files may
be more efficient than using *Note `mysqldump': mysqldump. and
importing the file on each slave.

However, using this method with tables in storage engines with complex
caching or logging algorithms may not give you a perfect `in time'
snapshot as cache information and logging updates may not have been
applied, even if you have acquired a global read lock. How the storage
engine responds to this depends on its crash recovery abilities.

In addition, this method does not work reliably if the master and slave
have different values for `ft_stopword_file', `ft_min_word_len', or
`ft_max_word_len' and you are copying tables having full-text indexes.

If you are using `InnoDB' tables, you can use the ``InnoDB' Hot Backup'
tool to obtain a consistent snapshot. This tool records the log name
and offset corresponding to the snapshot to be later used on the slave.
`Hot Backup' is a nonfree (commercial) tool that is not included in the
standard MySQL distribution.  See the ``InnoDB' Hot Backup' home page at
`http://www.innodb.com/wp/products/hot-backup/' for detailed
information.

Otherwise, you can obtain a reliable binary snapshot of `InnoDB' tables
only after shutting down the MySQL Server.

To create a raw data snapshot of `MyISAM' tables you can use standard
copy tools such as `cp' or `copy', a remote copy tool such as `scp' or
`rsync', an archiving tool such as `zip' or `tar', or a file system
snapshot tool such as `dump', providing that your MySQL data files
exist on a single file system. If you are replicating only certain
databases then make sure you copy only those files that related to
those tables. (For `InnoDB', all tables in all databases are stored in
the shared tablespace files, unless you have the
`innodb_file_per_table' option enabled.)

You may want to specifically exclude the following files from your
archive:

   * Files relating to the `mysql' database.

   * The `master.info' file.

   * The master's binary log files.

   * Any relay log files.

To get the most consistent results with a raw data snapshot you should
shut down the master server during the process, as follows:

  1. Acquire a read lock and get the master's status. See *Note
     replication-howto-masterstatus::.

  2. In a separate session, shut down the master server:

          shell> mysqladmin shutdown

  3. Make a copy of the MySQL data files. The following examples show
     common ways to do this. You need to choose only one of them:

          shell> tar cf /TMP/DB.TAR ./DATA
          shell> zip -r /TMP/DB.ZIP ./DATA
          shell> rsync --recursive ./DATA /TMP/DBDATA

  4. Restart the master server.

If you are not using `InnoDB' tables, you can get a snapshot of the
system from a master without shutting down the server as described in
the following steps:

  1. Acquire a read lock and get the master's status. See *Note
     replication-howto-masterstatus::.

  2. Make a copy of the MySQL data files. The following examples show
     common ways to do this. You need to choose only one of them:

          shell> tar cf /TMP/DB.TAR ./DATA
          shell> zip -r /TMP/DB.ZIP ./DATA
          shell> rsync --recursive ./DATA /TMP/DBDATA

  3. In the client where you acquired the read lock, release the lock:

          mysql> UNLOCK TABLES;

Once you have created the archive or copy of the database, you will
need to copy the files to each slave before starting the slave
replication process.


File: manual.info,  Node: replication-howto-newservers,  Next: replication-howto-existingdata,  Prev: replication-howto-rawdata,  Up: replication-howto

16.1.1.7 Setting Up Replication with New Master and Slaves
..........................................................

The easiest and most straightforward method for setting up replication
is to use new master and slave servers.

You can also use this method if you are setting up new servers but have
an existing dump of the databases from a different server that you want
to load into your replication configuration. By loading the data into a
new master, the data will be automatically replicated to the slaves.

To set up replication between a new master and slave:

  1. Configure the MySQL master with the necessary configuration
     properties. See *Note replication-howto-masterbaseconfig::.

  2. Start up the MySQL master.

  3. Set up a user. See *Note replication-howto-repuser::.

  4. Obtain the master status information. See *Note
     replication-howto-masterstatus::.

  5. On the master, release the read lock:

          mysql> UNLOCK TABLES;

  6. On the slave, edit the MySQL configuration. See *Note
     replication-howto-slavebaseconfig::.

  7. Start up the MySQL slave.

  8. Execute a *Note `CHANGE MASTER TO': change-master-to.  statement
     to set the master replication server configuration. See *Note
     replication-howto-slaveinit::.

Perform the slave setup steps on each slave.

Because there is no data to load or exchange on a new server
configuration you do not need to copy or import any information.

If you are setting up a new replication environment using the data from
a different existing database server, you will now need to run the dump
file generated from that server on the new master. The database updates
will automatically be propagated to the slaves:

     shell> mysql -h master < fulldb.dump


File: manual.info,  Node: replication-howto-existingdata,  Next: replication-howto-additionalslaves,  Prev: replication-howto-newservers,  Up: replication-howto

16.1.1.8 Setting Up Replication with Existing Data
..................................................

When setting up replication with existing data, you will need to decide
how best to get the data from the master to the slave before starting
the replication service.

The basic process for setting up replication with existing data is as
follows:

  1. With the MySQL master running, create a user to be used by the
     slave when connecting to the master during replication.  See *Note
     replication-howto-repuser::.

  2. If you have not already configured the `server-id' and enabled
     binary logging on the master server, you will need to shut it down
     to configure these options. See *Note
     replication-howto-masterbaseconfig::.

     If you have to shut down your master server, this is a good
     opportunity to take a snapshot of its databases. You should obtain
     the master status (see *Note replication-howto-masterstatus::)
     before taking down the master, updating the configuration and
     taking a snapshot. For information on how to create a snapshot
     using raw data files, see *Note replication-howto-rawdata::.

  3. If your master server is already correctly configured, obtain its
     status (see *Note replication-howto-masterstatus::) and then use
     *Note `mysqldump': mysqldump. to take a snapshot (see *Note
     replication-howto-mysqldump::) or take a raw snapshot of the live
     server using the guide in *Note replication-howto-rawdata::.

  4. Update the configuration of the slave. See *Note
     replication-howto-slavebaseconfig::.

  5. The next step depends on how you created the snapshot of data on
     the master.

     If you used *Note `mysqldump': mysqldump.:

       1. Start the slave, using the `--skip-slave-start' option so
          that replication does not start.

       2. Import the dump file:

               shell> mysql < fulldb.dump

     If you created a snapshot using the raw data files:

       1. Extract the data files into your slave data directory.  For
          example:

               shell> tar xvf dbdump.tar

          You may need to set permissions and ownership on the files so
          that the slave server can access and modify them.

       2. Start the slave, using the `--skip-slave-start' option so
          that replication does not start.

  6. Configure the slave with the replication coordinates from the
     master. This tells the slave the binary log file and position
     within the file where replication needs to start.  Also, configure
     the slave with the login credentials and host name of the master.
     For more information on the *Note `CHANGE MASTER TO':
     change-master-to. statement required, see *Note
     replication-howto-slaveinit::.

  7. Start the slave threads:

          mysql> START SLAVE;

After you have performed this procedure, the slave should connect to
the master and catch up on any updates that have occurred since the
snapshot was taken.

If you have forgotten to set the `server-id' option for the master,
slaves cannot connect to it.

If you have forgotten to set the `server-id' option for the slave, you
get the following error in the slave's error log:

     Warning: You should set server-id to a non-0 value if master_host
     is set; we will force server id to 2, but this MySQL server will
     not act as a slave.

You also find error messages in the slave's error log if it is not able
to replicate for any other reason.

Once a slave is replicating, you can find in its data directory one
file named `master.info' and another named `relay-log.info'. The slave
uses these two files to keep track of how much of the master's binary
log it has processed. Do _not_ remove or edit these files unless you
know exactly what you are doing and fully understand the implications.
Even in that case, it is preferred that you use the *Note `CHANGE
MASTER TO': change-master-to.  statement to change replication
parameters. The slave will use the values specified in the statement to
update the status files automatically.

*Note*:

The content of `master.info' overrides some of the server options
specified on the command line or in `my.cnf'. See *Note
replication-options::, for more details.

A single snapshot of the master suffices for multiple slaves. To set up
additional slaves, use the same master snapshot and follow the slave
portion of the procedure just described.


File: manual.info,  Node: replication-howto-additionalslaves,  Next: replication-howto-slaveinit,  Prev: replication-howto-existingdata,  Up: replication-howto

16.1.1.9 Introducing Additional Slaves to an Existing Replication Environment
.............................................................................

To add another slave to an existing replication configuration, you can
do so without stopping the master. Instead, set up the new slave by
making a copy of an existing slave, except that you configure the new
slave with a different `server-id' value.

To duplicate an existing slave:

  1. Shut down the existing slave:

          shell> mysqladmin shutdown

  2. Copy the data directory from the existing slave to the new slave.
     You can do this by creating an archive using `tar' or `WinZip', or
     by performing a direct copy using a tool such as `cp' or `rsync'.
     Ensure that you also copy the log files and relay log files.

     A common problem that is encountered when adding new replication
     slaves is that the new slave fails with a series of warning and
     error messages like these:

          071118 16:44:10 [Warning] Neither --relay-log nor --relay-log-index were used; so
          replication may break when this MySQL server acts as a slave and has his hostname
          changed!! Please use '--relay-log=NEW_SLAVE_HOSTNAME-relay-bin' to avoid this problem.
          `071118 16:44:10 [ERROR] Failed to open the relay log './OLD_SLAVE_HOSTNAME-relay-bin.003525'
          (relay_log_pos 22940879)'
          071118 16:44:10 `[ERROR] Could not find target log during relay log initialization'
          071118 16:44:10 `[ERROR] Failed to initialize the master info structure'

     This is due to the fact that, if the `--relay-log' option is not
     specified, the relay log files contain the host name as part of
     their file names. (This is also true of the relay log index file
     if the `--relay-log-index' option is not used. See *Note
     replication-options::, for more information about these options.)

     To avoid this problem, use the same value for `--relay-log' on the
     new slave that was used on the existing slave. (If this option was
     not set explicitly on the existing slave, use
     `EXISTING_SLAVE_HOSTNAME-relay-bin'.)  If this is not feasible,
     copy the existing slave's relay log index file to the new slave
     and set the `--relay-log-index' option on the new slave to match
     what was used on the existing slave.  (If this option was not set
     explicitly on the existing slave, use
     `EXISTING_SLAVE_HOSTNAME-relay-bin.index'.)  Alternatively--if you
     have already tried to start the new slave (after following the
     remaining steps in this section) and have encountered errors like
     those described previously--then perform the following steps:

       1. If you have not already done so, issue a *Note `STOP SLAVE':
          stop-slave. on the new slave.

          If you have already started the existing slave again, issue a
          *Note `STOP SLAVE': stop-slave. on the existing slave as well.

       2. Copy the contents of the existing slave's relay log index
          file into the new slave's relay log index file, making sure
          to overwrite any content already in the file.

       3. Proceed with the remaining steps in this section.

  3. Copy the `master.info' and `relay-log.info' files from the existing
     slave to the new slave if they were not located in the data
     directory. These files hold the current log coordinates for the
     master's binary log and the slave's relay log.

  4. Start the existing slave.

  5. On the new slave, edit the configuration and give the new slave a
     unique `server-id' not used by the master or any of the existing
     slaves.

  6. Start the new slave. The slave will use the information in its
     `master.info' file to start the replication process.


File: manual.info,  Node: replication-howto-slaveinit,  Prev: replication-howto-additionalslaves,  Up: replication-howto

16.1.1.10 Setting the Master Configuration on the Slave
.......................................................

To set up the slave to communicate with the master for replication, you
must tell the slave the necessary connection information. To do this,
execute the following statement on the slave, replacing the option
values with the actual values relevant to your system:

     mysql> CHANGE MASTER TO
         ->     MASTER_HOST='MASTER_HOST_NAME',
         ->     MASTER_USER='REPLICATION_USER_NAME',
         ->     MASTER_PASSWORD='REPLICATION_PASSWORD',
         ->     MASTER_LOG_FILE='RECORDED_LOG_FILE_NAME',
         ->     MASTER_LOG_POS=RECORDED_LOG_POSITION;

*Note*:

Replication cannot use Unix socket files. You must be able to connect
to the master MySQL server using TCP/IP.

The *Note `CHANGE MASTER TO': change-master-to. statement has other
options as well. For example, it is possible to set up secure
replication using SSL. For a full list of options, and information
about the maximum permissible length for the string-valued options, see
*Note change-master-to::.


File: manual.info,  Node: replication-options,  Next: replication-administration,  Prev: replication-howto,  Up: replication-configuration

16.1.2 Replication and Binary Logging Options and Variables
-----------------------------------------------------------

* Menu:

* replication-options-table::    Replication and Binary Logging Option and Variable Reference
* replication-options-master::   Replication Master Options and Variables
* replication-options-slave::    Replication Slave Options and Variables
* replication-options-binary-log::  Binary Log Options and Variables

The next few sections contain information about *Note `mysqld': mysqld.
options and server variables that are used in replication and for
controlling the binary log. Options and variables for use on
replication masters and replication slaves are covered separately, as
are options and variables relating to binary logging. A set of
quick-reference tables providing basic information about these options
and variables is also included (in the next section following this one).

Of particular importance is the `--server-id' option.

Options for server-id *Command-Line Format*  `--server-id=#'        
*Option-File Format*   `server-id'        
*Option Sets Variable* Yes,            
                       `server_id'        
*Variable Name*        `server_id'        
*Variable Scope*       Global          
*Dynamic Variable*     Yes             
                       *Permitted        
                       Values          
                       *               
*Type*                 `numeric'        
*Default*              `0'             
*Range*                `0 ..           
                       4294967295'        


This option is common to both master and slave replication servers, and
is used in replication to enable master and slave servers to identify
themselves uniquely. For additional information, see *Note
replication-options-master::, and *Note replication-options-slave::.

On the master and each slave, you _must_ use the `--server-id' option
to establish a unique replication ID in the range from 1 to 2^32 - 1.
`Unique', means that each ID must be different from every other ID in
use by any other replication master or slave. Example: `server-id=3'.

If you omit `--server-id', the default ID is 0, in which case a master
refuses connections from all slaves, and a slave refuses to connect to
a master. For more information, see *Note
replication-howto-slavebaseconfig::.


File: manual.info,  Node: replication-options-table,  Next: replication-options-master,  Prev: replication-options,  Up: replication-options

16.1.2.1 Replication and Binary Logging Option and Variable Reference
.....................................................................

The following tables list basic information about the MySQL
command-line options and system variables applicable to replication and
the binary log.

*Replication Option/Variable Summary*

Name           Cmd-Line    Option file System Var  Status Var  Var Scope   Dynamic
abort-slave-event-countYes         Yes                                             
Com_change_master                                    Yes         Both        No
Com_show_master_status                                    Yes         Both        No
Com_show_new_master                                    Yes         Both        No
Com_show_slave_hosts                                    Yes         Both        No
Com_show_slave_status                                    Yes         Both        No
Com_slave_start                                    Yes         Both        No
Com_slave_stop                                     Yes         Both        No
disconnect-slave-event-countYes         Yes                                             
init_slave     Yes         Yes         Yes                     Global      Yes
log-slave-updatesYes         Yes                                 Global      No
- _Variable_:                          Yes                     Global      No
log_slave_updates                                                            
master-connect-retryYes         Yes                                             
master-host    Yes         Yes                                             
master-info-fileYes         Yes                                             
master-passwordYes         Yes                                             
master-port    Yes         Yes                                             
master-retry-countYes         Yes                                             
master-ssl     Yes         Yes                                             
master-ssl-ca  Yes         Yes                                             
master-ssl-capathYes         Yes                                             
master-ssl-certYes         Yes                                             
master-ssl-cipherYes         Yes                                             
master-ssl-key Yes         Yes                                             
master-user    Yes         Yes                                             
relay-log      Yes         Yes                                             
relay-log-indexYes         Yes                                 Both        No
- _Variable_:                          Yes                     Both        No
relay_log_index                                                            
relay_log_indexYes         Yes         Yes                     Global      No
relay-log-info-fileYes         Yes                                             
- _Variable_:                                                              
relay_log_info_file                                                            
relay_log_info_fileYes         Yes         Yes                     Global      No
relay_log_purgeYes         Yes         Yes                     Global      Yes
relay_log_space_limitYes         Yes         Yes                     Global      No
replicate-do-dbYes         Yes                                             
replicate-do-tableYes         Yes                                             
replicate-ignore-dbYes         Yes                                             
replicate-ignore-tableYes         Yes                                             
replicate-rewrite-dbYes         Yes                                             
replicate-same-server-idYes         Yes                                             
replicate-wild-do-tableYes         Yes                                             
replicate-wild-ignore-tableYes         Yes                                             
report-host    Yes         Yes                                 Global      No
- _Variable_:                          Yes                     Global      No
report_host                                                                
report-passwordYes         Yes                                 Global      No
- _Variable_:                          Yes                     Global      No
report_password                                                            
report-port    Yes         Yes                                 Global      No
- _Variable_:                          Yes                     Global      No
report_port                                                                
report-user    Yes         Yes                                 Global      No
- _Variable_:                          Yes                     Global      No
report_user                                                                
rpl_recovery_rank                        Yes                     Global      Yes
Rpl_status                                         Yes         Global      No
show-slave-auth-infoYes         Yes                                             
skip-slave-startYes         Yes                                             
slave_compressed_protocolYes         Yes         Yes                     Global      Yes
slave-load-tmpdirYes         Yes                                 Global      No
- _Variable_:                          Yes                     Global      No
slave_load_tmpdir                                                            
slave-net-timeoutYes         Yes                                 Global      Yes
- _Variable_:                          Yes                     Global      Yes
slave_net_timeout                                                            
Slave_open_temp_tables                                    Yes         Global      No
Slave_retried_transactions                                    Yes         Global      No
Slave_running                                      Yes         Global      No
slave-skip-errorsYes         Yes                                 Global      No
- _Variable_:                          Yes                     Global      No
slave_skip_errors                                                            
slave_transaction_retriesYes         Yes         Yes                     Global      Yes
sql_slave_skip_counter                        Yes                     Global      Yes

*Note replication-options-master::, provides more detailed information
about options and variables relating to replication master servers. For
more information about options and variables relating to replication
slaves, see *Note replication-options-slave::.

*Binary Logging Option/Variable Summary*

Name           Cmd-Line    Option file System Var  Status Var  Var Scope   Dynamic
Binlog_cache_disk_use                                    Yes         Global      No
binlog_cache_sizeYes         Yes         Yes                     Global      Yes
Binlog_cache_use                                    Yes         Global      No
binlog-do-db   Yes         Yes                                             
binlog-ignore-dbYes         Yes                                             
Com_show_binlog_events                                    Yes         Both        No
Com_show_binlogs                                    Yes         Both        No
max_binlog_cache_sizeYes         Yes         Yes                     Global      Yes
max-binlog-dump-eventsYes         Yes                                             
max_binlog_sizeYes         Yes         Yes                     Global      Yes
sporadic-binlog-dump-failYes         Yes                                             

*Note replication-options-binary-log::, provides more detailed
information about options and variables relating to binary logging. For
additional general information about the binary log, see *Note
binary-log::.

For a table showing _all_ command-line options, system and status
variables used with *Note `mysqld': mysqld, see *Note
mysqld-option-tables::.


File: manual.info,  Node: replication-options-master,  Next: replication-options-slave,  Prev: replication-options-table,  Up: replication-options

16.1.2.2 Replication Master Options and Variables
.................................................

This section describes the server options and system variables that you
can use on replication master servers. You can specify the options
either on the *Note command line: command-line-options. or in an *Note
option file: option-files. You can specify system variable values using
*Note `SET': set-option.

On the master and each slave, you must use the `server-id' option to
establish a unique replication ID. For each server, you should pick a
unique positive integer in the range from 1 to 2^32 - 1, and each ID
must be different from every other ID in use by any other replication
master or slave. Example: `server-id=3'.

For options used on the master for controlling binary logging, see
*Note replication-options-binary-log::.

   *  `auto_increment_increment'

     Options for auto_increment_increment      *Version Introduced* 5.0.2           
     *Command-Line        `--auto-increment-increment[=#]'        
     Format*                              
     *Option-File Format* `auto_increment_increment'        
     *Option Sets         Yes,            
     Variable*            `auto_increment_increment'        
     *Variable Name*      `auto_increment_increment'        
     *Variable Scope*     Global,         
                          Session         
     *Dynamic Variable*   Yes             
                          *Permitted        
                          Values          
                          *               
     *Type*               `numeric'        
     *Default*            `1'             
     *Range*              `1 ..           
                          65535'          


     `auto_increment_increment' and `auto_increment_offset' are
     intended for use with master-to-master replication, and can be
     used to control the operation of `AUTO_INCREMENT' columns. Both
     variables have global and session values, and each can assume an
     integer value between 1 and 65,535 inclusive. Setting the value of
     either of these two variables to 0 causes its value to be set to 1
     instead. Attempting to set the value of either of these two
     variables to an integer greater than 65,535 or less than 0 causes
     its value to be set to 65,535 instead. Attempting to set the value
     of `auto_increment_increment' or `auto_increment_offset' to a
     noninteger value gives rise to an error, and the actual value of
     the variable remains unchanged.

     These two variables affect `AUTO_INCREMENT' column behavior as
     follows:

        * `auto_increment_increment' controls the interval between
          successive column values.  For example:

               mysql> SHOW VARIABLES LIKE 'auto_inc%';
               +--------------------------+-------+
               | Variable_name            | Value |
               +--------------------------+-------+
               | auto_increment_increment | 1     |
               | auto_increment_offset    | 1     |
               +--------------------------+-------+
               2 rows in set (0.00 sec)

               mysql> CREATE TABLE autoinc1
                   -> (col INT NOT NULL AUTO_INCREMENT PRIMARY KEY);
                 Query OK, 0 rows affected (0.04 sec)

               mysql> SET @@auto_increment_increment=10;
               Query OK, 0 rows affected (0.00 sec)

               mysql> SHOW VARIABLES LIKE 'auto_inc%';
               +--------------------------+-------+
               | Variable_name            | Value |
               +--------------------------+-------+
               | auto_increment_increment | 10    |
               | auto_increment_offset    | 1     |
               +--------------------------+-------+
               2 rows in set (0.01 sec)

               mysql> INSERT INTO autoinc1 VALUES (NULL), (NULL), (NULL), (NULL);
               Query OK, 4 rows affected (0.00 sec)
               Records: 4  Duplicates: 0  Warnings: 0

               mysql> SELECT col FROM autoinc1;
               +-----+
               | col |
               +-----+
               |   1 |
               |  11 |
               |  21 |
               |  31 |
               +-----+
               4 rows in set (0.00 sec)

        * `auto_increment_offset' determines the starting point for the
          `AUTO_INCREMENT' column value. Consider the following,
          assuming that these statements are executed during the same
          session as the example given in the description for
          `auto_increment_increment':

               mysql> SET @@auto_increment_offset=5;
               Query OK, 0 rows affected (0.00 sec)

               mysql> SHOW VARIABLES LIKE 'auto_inc%';
               +--------------------------+-------+
               | Variable_name            | Value |
               +--------------------------+-------+
               | auto_increment_increment | 10    |
               | auto_increment_offset    | 5     |
               +--------------------------+-------+
               2 rows in set (0.00 sec)

               mysql> CREATE TABLE autoinc2
                   -> (col INT NOT NULL AUTO_INCREMENT PRIMARY KEY);
               Query OK, 0 rows affected (0.06 sec)

               mysql> INSERT INTO autoinc2 VALUES (NULL), (NULL), (NULL), (NULL);
               Query OK, 4 rows affected (0.00 sec)
               Records: 4  Duplicates: 0  Warnings: 0

               mysql> SELECT col FROM autoinc2;
               +-----+
               | col |
               +-----+
               |   5 |
               |  15 |
               |  25 |
               |  35 |
               +-----+
               4 rows in set (0.02 sec)

          If the value of `auto_increment_offset' is greater than that
          of `auto_increment_increment', the value of
          `auto_increment_offset' is ignored.

     Should one or both of these variables be changed and then new rows
     inserted into a table containing an `AUTO_INCREMENT' column, the
     results may seem counterintuitive because the series of
     `AUTO_INCREMENT' values is calculated without regard to any values
     already present in the column, and the next value inserted is the
     least value in the series that is greater than the maximum
     existing value in the `AUTO_INCREMENT' column. In other words, the
     series is calculated like so:

     `auto_increment_offset' + N x `auto_increment_increment'

     where N is a positive integer value in the series [1, 2, 3, ...].
     For example:

          mysql> SHOW VARIABLES LIKE 'auto_inc%';
          +--------------------------+-------+
          | Variable_name            | Value |
          +--------------------------+-------+
          | auto_increment_increment | 10    |
          | auto_increment_offset    | 5     |
          +--------------------------+-------+
          2 rows in set (0.00 sec)

          mysql> SELECT col FROM autoinc1;
          +-----+
          | col |
          +-----+
          |   1 |
          |  11 |
          |  21 |
          |  31 |
          +-----+
          4 rows in set (0.00 sec)

          mysql> INSERT INTO autoinc1 VALUES (NULL), (NULL), (NULL), (NULL);
          Query OK, 4 rows affected (0.00 sec)
          Records: 4  Duplicates: 0  Warnings: 0

          mysql> SELECT col FROM autoinc1;
          +-----+
          | col |
          +-----+
          |   1 |
          |  11 |
          |  21 |
          |  31 |
          |  35 |
          |  45 |
          |  55 |
          |  65 |
          +-----+
          8 rows in set (0.00 sec)

     The values shown for `auto_increment_increment' and
     `auto_increment_offset' generate the series 5 + N x 10, that is,
     [5, 15, 25, 35, 45, ...]. The greatest value present in the `col'
     column prior to the *Note `INSERT': insert. is 31, and the next
     available value in the `AUTO_INCREMENT' series is 35, so the
     inserted values for `col' begin at that point and the results are
     as shown for the *Note `SELECT': select. query.

     It is not possible to confine the effects of these two variables
     to a single table, and thus they do not take the place of the
     sequences offered by some other database management systems; these
     variables control the behavior of all `AUTO_INCREMENT' columns in
     _all_ tables on the MySQL server. If the global value of either
     variable is set, its effects persist until the global value is
     changed or overridden by setting the session value, or until *Note
     `mysqld': mysqld. is restarted. If the local value is set, the new
     value affects `AUTO_INCREMENT' columns for all tables into which
     new rows are inserted by the current user for the duration of the
     session, unless the values are changed during that session.

     The `auto_increment_increment' variable was added in MySQL 5.0.2.
     Its default value is 1. See *Note
     replication-features-auto-increment::.

     `auto_increment_increment' is supported for use with *Note `NDB':
     mysql-cluster. tables beginning with MySQL 5.0.46. Previously,
     setting it when using MySQL Cluster tables produced unpredictable
     results.

   *  `auto_increment_offset'

     Options for auto_increment_offset      *Version Introduced* 5.0.2           
     *Command-Line        `--auto-increment-offset[=#]'        
     Format*                              
     *Option-File Format* `auto_increment_offset'        
     *Option Sets         Yes,            
     Variable*            `auto_increment_offset'        
     *Variable Name*      `auto_increment_offset'        
     *Variable Scope*     Global,         
                          Session         
     *Dynamic Variable*   Yes             
                          *Permitted        
                          Values          
                          *               
     *Type*               `numeric'        
     *Default*            `1'             
     *Range*              `1 ..           
                          65535'          


     This variable was introduced in MySQL 5.0.2. Its default value is
     1. For particulars, see the description for
     `auto_increment_increment'.

     `auto_increment_offset' is supported for use with *Note `NDB':
     mysql-cluster. tables beginning with MySQL 5.0.46. Previously,
     setting it when using MySQL Cluster tables produced unpredictable
     results.


File: manual.info,  Node: replication-options-slave,  Next: replication-options-binary-log,  Prev: replication-options-master,  Up: replication-options

16.1.2.3 Replication Slave Options and Variables
................................................

This section describes the server options and system variables that
apply to slave replication servers. You can specify the options either
on the *Note command line: command-line-options. or in an *Note option
file: option-files. Many of the options can be set while the server is
running by using the *Note `CHANGE MASTER TO': change-master-to.
statement. You can specify system variable values using *Note `SET':
set-option.

Server ID

On the master and each slave, you must use the `server-id' option to
establish a unique replication ID in the range from 1 to 2^32 - 1.
`Unique' means that each ID must be different from every other ID in use
by any other replication master or slave. Example `my.cnf' file:

     [mysqld]
     server-id=3

Some slave server replication options are handled in a special way, in
the sense that each is ignored if a `master.info' file exists when the
slave starts and contains a value for the option. The following options
are handled this way:

   * `--master-host'

   * `--master-user'

   * `--master-password'

   * `--master-port'

   * `--master-connect-retry'

   * `--master-ssl'

   * `--master-ssl-ca'

   * `--master-ssl-capath'

   * `--master-ssl-cert'

   * `--master-ssl-cipher'

   * `--master-ssl-key'

The `master.info' file format in MySQL 5.0 includes as its first line
the number of lines in the file. (See *Note slave-logs::.) If you
upgrade an older server (before MySQL 4.1.1) to a newer version, the new
server upgrades the `master.info' file to the new format automatically
when it starts. However, if you downgrade a newer server to a version
older than 4.1.1, you should manually remove the first line before
starting the older server for the first time. Note that, in this case,
the downgraded server can no longer use an SSL connection to
communicate with the master.

If no `master.info' file exists when the slave server starts, it uses
the values for those options that are specified in option files or on
the command line. This occurs when you start the server as a
replication slave for the very first time, or when you have run *Note
`RESET SLAVE': reset-slave. and then have shut down and restarted the
slave.

If the `master.info' file exists when the slave server starts, the
server uses its contents and ignores any startup options that
correspond to the values listed in the file.  Thus, if you start the
slave server with different values of the startup options that
correspond to values in the `master.info' file, the different values
have no effect because the server continues to use the `master.info'
file. To use different values, the preferred method is to use the *Note
`CHANGE MASTER TO': change-master-to. statement to reset the values
while the slave is running. Alternatively, you can stop the server,
remove the `master.info' file, and restart the server with different
option values.

Suppose that you specify this option in your `my.cnf' file:

     [mysqld]
     master-host=SOME_HOST

The first time you start the server as a replication slave, it reads
and uses that option from the `my.cnf' file. The server then records
the value in the `master.info' file. The next time you start the
server, it reads the master host value from the `master.info' file only
and ignores the value in the option file. If you modify the `my.cnf'
file to specify a different master host of SOME_OTHER_HOST, the change
still has no effect. You should use *Note `CHANGE MASTER TO':
change-master-to. instead.

Because the server gives an existing `master.info' file precedence over
the startup options just described, you might prefer not to use startup
options for these values at all, and instead specify them by using the
*Note `CHANGE MASTER TO': change-master-to. statement. See *Note
change-master-to::.

This example shows a more extensive use of startup options to configure
a slave server:

     [mysqld]
     server-id=2
     master-host=db-master.mycompany.com
     master-port=3306
     master-user=pertinax
     master-password=freitag
     master-connect-retry=60
     report-host=db-slave.mycompany.com

Startup options for replication slaves

The following list describes startup options for controlling
replication slave servers. Many of these options can be set while the
server is running by using the *Note `CHANGE MASTER TO':
change-master-to. statement.  Others, such as the `--replicate-*'
options, can be set only when the slave server starts.
Replication-related system variables are discussed later in this
section.

   *  `--abort-slave-event-count'

     Options for abort-slave-event-count      *Command-Line        `--abort-slave-event-count=#'        
     Format*                              
     *Option-File Format* `abort-slave-event-count'        
                          *Permitted        
                          Values          
                          *               
     *Type*               `numeric'        
     *Default*            `0'             
     *Min Value*          `0'             


     When this option is set to some positive integer VALUE other than
     0 (the default) it affects replication behavior as follows: After
     the slave SQL thread has started, VALUE log events are permitted
     to be executed; after that, the slave SQL thread does not receive
     any more events, just as if the network connection from the master
     were cut. The slave thread continues to run, and the output from
     *Note `SHOW SLAVE STATUS': show-slave-status. displays `Yes' in
     both the `Slave_IO_Running' and the `Slave_SQL_Running' columns,
     but no further events are read from the relay log.

     This option is used internally by the MySQL test suite for
     replication testing and debugging. It is not intended for use in a
     production setting.

   *  `--disconnect-slave-event-count'

     Options for disconnect-slave-event-count      *Command-Line        `--disconnect-slave-event-count=#'        
     Format*                              
     *Option-File Format* `disconnect-slave-event-count'        
                          *Permitted        
                          Values          
                          *               
     *Type*               `numeric'        
     *Default*            `0'             


     This option is used internally by the MySQL test suite for
     replication testing and debugging.

   *  `--log-slave-updates'

     Options for log-slave-updates      *Command-Line        `--log-slave-updates'        
     Format*                              
     *Option-File Format* `log-slave-updates'        
     *Option Sets         Yes,            
     Variable*            `log_slave_updates'        
     *Variable Name*      `log_slave_updates'        
     *Variable Scope*     Global          
     *Dynamic Variable*   No              
                          *Permitted        
                          Values          
                          *               
     *Type*               `boolean'        
     *Default*            `FALSE'         


     Normally, a slave does not log to its own binary log any updates
     that are received from a master server. This option tells the
     slave to log the updates performed by its SQL thread to its own
     binary log. For this option to have any effect, the slave must
     also be started with the `--log-bin' option to enable binary
     logging.  `--log-slave-updates' is used when you want to chain
     replication servers. For example, you might want to set up
     replication servers using this arrangement:

          A -> B -> C

     Here, `A' serves as the master for the slave `B', and `B' serves
     as the master for the slave `C'. For this to work, `B' must be
     both a master _and_ a slave. You must start both `A' and `B' with
     `--log-bin' to enable binary logging, and `B' with the
     `--log-slave-updates' option so that updates received from `A' are
     logged by `B' to its binary log.

   * `--log-warnings[=LEVEL]'

     Options for log-warnings      *Command-Line        `--log-warnings[=#]'        
     Format*                              
     **                   `-W             
                          [#]'            
     *Option-File Format* `log-warnings'        
     *Option Sets         Yes,            
     Variable*            `log_warnings'        
     *Variable Name*      `log_warnings'        
     *Variable Scope*     Global,         
                          Session         
     *Dynamic Variable*   Yes             
     *Disabled by*        `skip-log-warnings'        
                          *Permitted        
                          Values          
                          *               
     *Platform Bit Size*  `64'            
     *Type*               `numeric'        
     *Default*            `1'             
     *Range*              `0 ..           
                          18446744073709547520'        


     This option causes a server to print more messages to the error
     log about what it is doing. With respect to replication, the
     server generates warnings that it succeeded in reconnecting after
     a network/connection failure, and informs you as to how each slave
     thread started. This option is enabled by default; to disable it,
     use `--skip-log-warnings'.  Aborted connections are not logged to
     the error log unless the value is greater than 1.

     Note that the effects of this option are not limited to
     replication. It produces warnings across a spectrum of server
     activities.

   *  `--master-connect-retry=SECONDS'

     Options for master-connect-retry      *Command-Line        `--master-connect-retry=#'        
     Format*                              
     *Option-File Format* `master-connect-retry'        
     *Deprecated*         5.1.17          
                          *Permitted        
                          Values          
                          *               
     *Type*               `numeric'        
     *Default*            `60'            


     The number of seconds that the slave thread sleeps before trying
     to reconnect to the master in case the master goes down or the
     connection is lost. The value in the `master.info' file takes
     precedence if it can be read. If not set, the default is 60.
     Connection retries are not invoked until the slave times out
     reading data from the master according to the value of
     `--slave-net-timeout'. The number of reconnection attempts is
     limited by the `--master-retry-count' option.

   *  `--master-host=HOST_NAME'

     Options for master-host      *Command-Line        `--master-host=name'        
     Format*                              
     *Option-File Format* `master-host'        
     *Deprecated*         5.1.17          
                          *Permitted        
                          Values          
                          *               
     *Type*               `string'        


     The host name or IP address of the master replication server.  The
     value in `master.info' takes precedence if it can be read. If no
     master host is specified, the slave thread does not start.

   *  `--master-info-file=FILE_NAME'

     Options for master-info-file      *Command-Line        `--master-info-file=file_name'        
     Format*                              
     *Option-File Format* `master-info-file=file_name'        
                          *Permitted        
                          Values          
                          *               
     *Type*               `file           
                          name'           
     *Default*            `master.info'        


     The name to use for the file in which the slave records
     information about the master. The default name is `master.info' in
     the data directory. For information about the format of this file,
     see *Note slave-logs-status::.

   *  `--master-password=PASSWORD'

     Options for master-password      *Command-Line        `--master-password=name'        
     Format*                              
     *Option-File Format* `master-password'        
     *Deprecated*         5.1.17          
                          *Permitted        
                          Values          
                          *               
     *Type*               `string'        


     The password of the account that the slave thread uses for
     authentication when it connects to the master. The value in the
     `master.info' file takes precedence if it can be read. If not set,
     an empty password is assumed.

   *  `--master-port=PORT_NUMBER'

     Options for master-port      *Command-Line        `--master-port=#'        
     Format*                              
     *Option-File Format* `master-port'        
     *Deprecated*         5.1.17          
                          *Permitted        
                          Values          
                          *               
     *Type*               `numeric'        
     *Default*            `3306'          


     The TCP/IP port number that the master is listening on. The value
     in the `master.info' file takes precedence if it can be read. If
     not set, the compiled-in setting is assumed (normally 3306).

   *  `--master-retry-count=COUNT'

     Options for master-retry-count      *Command-Line        `--master-retry-count=#'        
     Format*                              
     *Option-File Format* `master-retry-count'        
     *Deprecated*         5.6.1           
                          *Permitted        
                          Values          
                          *               
     *Platform Bit Size*  `32'            
     *Type*               `numeric'        
     *Default*            `86400'         
     *Range*              `0 ..           
                          4294967295'        
                          *Permitted        
                          Values          
                          *               
     *Platform Bit Size*  `64'            
     *Type*               `numeric'        
     *Default*            `86400'         
     *Range*              `0 ..           
                          18446744073709551615'        


     The number of times that the slave tries to connect to the master
     before giving up. Reconnects are attempted at intervals set by the
     `--master-connect-retry' option (or the `MASTER_CONNECT_RETRY'
     option of the *Note `CHANGE MASTER TO': change-master-to.
     statement) and reconnects are triggered when data reads by the
     slave time out according to the `--slave-net-timeout' option. The
     default value is 86400. A value of 0 means `infinite'; the slave
     attempts to connect forever.

   *  `--master-ssl', `--master-ssl-ca=FILE_NAME',
     `--master-ssl-capath=DIRECTORY_NAME',
     `--master-ssl-cert=FILE_NAME', `--master-ssl-cipher=CIPHER_LIST',
     `--master-ssl-key=FILE_NAME'

     These options are used for setting up a secure replication
     connection to the master server using SSL. Their meanings are the
     same as the corresponding `--ssl', `--ssl-ca', `--ssl-capath',
     `--ssl-cert', `--ssl-cipher', `--ssl-key' options that are
     described in *Note ssl-options::. The values in the `master.info'
     file take precedence if they can be read.

   *  `--master-user=USER_NAME'

     Options for master-user      *Command-Line        `--master-user=name'        
     Format*                              
     *Option-File Format* `master-user'        
     *Deprecated*         5.1.17          
                          *Permitted        
                          Values          
                          *               
     *Type*               `string'        
     *Default*            `test'          


     The user name of the account that the slave thread uses for
     authentication when it connects to the master. This account must
     have the `REPLICATION SLAVE' privilege. The value in the
     `master.info' file takes precedence if it can be read. If the
     master user name is not set, the name `test' is assumed.

   *  `--max-relay-log-size=SIZE'

     The size at which the server rotates relay log files
     automatically. For more information, see *Note slave-logs::. The
     default size is 1GB.

   *  `--read-only'

     Cause the slave to permit no updates except from slave threads or
     from users having the `SUPER' privilege. On a slave server, this
     can be useful to ensure that the slave accepts updates only from
     its master server and not from clients. This variable does not
     apply to `TEMPORARY' tables.

   *  `--relay-log=FILE_NAME'

     Options for relay-log      *Command-Line        `--relay-log=name'        
     Format*                              
     *Option-File Format* `relay-log'        
                          *Permitted        
                          Values          
                          *               
     *Type*               `file           
                          name'           


     The basename for the relay log. The default basename is
     `HOST_NAME-relay-bin'.  The server writes the file in the data
     directory unless the basename is given with a leading absolute
     path name to specify a different directory. The server creates
     relay log files in sequence by adding a numeric suffix to the
     basename.

     Due to the manner in which MySQL parses server options, if you
     specify this option, you must supply a value; _the default
     basename is used only if the option is not actually specified_. If
     you use the `--relay-log' option without specifying a value,
     unexpected behavior is likely to result; this behavior depends on
     the other options used, the order in which they are specified, and
     whether they are specified on the command line or in an option
     file. For more information about how MySQL handles server options,
     see *Note program-options::.

     If you specify this option, the value specified is also used as
     the basename for the relay log index file. You can override this
     behavior by specifying a different relay log index file basename
     using the `--relay-log-index' option.

     You may find the `--relay-log' option useful in performing the
     following tasks:

        * Creating relay logs whose names are independent of host names.

        * If you need to put the relay logs in some area other than the
          data directory because your relay logs tend to be very large
          and you do not want to decrease `max_relay_log_size'.

        * To increase speed by using load-balancing between disks.

   *  `--relay-log-index=FILE_NAME'

     Options for relay-log-index      *Command-Line        `--relay-log-index=name'        
     Format*                              
     *Option-File Format* `relay-log-index'        
     *Option Sets         Yes,            
     Variable*            `relay_log_index'        
     *Variable Name*      `relay-log-index'        
     *Variable Scope*     Global,         
                          Session         
     *Dynamic Variable*   No              
                          *Permitted        
                          Values          
                          *               
     *Type*               `file           
                          name'           


     The name to use for the relay log index file. The default name is
     `HOST_NAME-relay-bin.index' in the data directory, where HOST_NAME
     is the name of the slave server.

     Due to the manner in which MySQL parses server options, if you
     specify this option, you must supply a value; _the default
     basename is used only if the option is not actually specified_. If
     you use the `--relay-log-index' option without specifying a value,
     unexpected behavior is likely to result; this behavior depends on
     the other options used, the order in which they are specified, and
     whether they are specified on the command line or in an option
     file. For more information about how MySQL handles server options,
     see *Note program-options::.

     If you specify this option, the value specified is also used as
     the basename for the relay logs. You can override this behavior by
     specifying a different relay log file basename using the
     `--relay-log' option.

   *  `--relay-log-info-file=FILE_NAME'

     Options for relay-log-info-file      *Command-Line        `--relay-log-info-file=file_name'        
     Format*                              
     *Option-File Format* `relay-log-info-file'        
     *Option Sets         Yes,            
     Variable*            `relay_log_info_file'        
                          *Permitted        
                          Values          
                          *               
     *Type*               `file           
                          name'           
     *Default*            `relay-log.info'        


     The name to use for the file in which the slave records
     information about the relay logs. The default name is
     `relay-log.info' in the data directory. For information about the
     format of this file, see *Note slave-logs-status::.

   *  `--relay-log-purge={0|1}'

     Disable or enable automatic purging of relay logs as soon as they
     are no longer needed. The default value is 1 (enabled).  This is a
     global variable that can be changed dynamically with `SET GLOBAL
     relay_log_purge = N'.

   *  `--relay-log-space-limit=SIZE'

     This option places an upper limit on the total size in bytes of
     all relay logs on the slave. A value of 0 means `no limit.' This
     is useful for a slave server host that has limited disk space.
     When the limit is reached, the I/O thread stops reading binary log
     events from the master server until the SQL thread has caught up
     and deleted some unused relay logs. Note that this limit is not
     absolute: There are cases where the SQL thread needs more events
     before it can delete relay logs. In that case, the I/O thread
     exceeds the limit until it becomes possible for the SQL thread to
     delete some relay logs because not doing so would cause a
     deadlock. You should not set `--relay-log-space-limit' to less
     than twice the value of `--max-relay-log-size' (or
     `--max-binlog-size' if `--max-relay-log-size' is 0). In that case,
     there is a chance that the I/O thread waits for free space because
     `--relay-log-space-limit' is exceeded, but the SQL thread has no
     relay log to purge and is unable to satisfy the I/O thread. This
     forces the I/O thread to ignore `--relay-log-space-limit'
     temporarily.

   *  `--replicate-do-db=DB_NAME'

     Options for replicate-do-db      *Command-Line        `--replicate-do-db=name'        
     Format*                              
     *Option-File Format* `replicate-do-db'        
                          *Permitted        
                          Values          
                          *               
     *Type*               `string'        


     Tell the slave SQL thread to restrict replication to statements
     where the default database (that is, the one selected by *Note
     `USE': use.) is DB_NAME. To specify more than one database, use
     this option multiple times, once for each database. Note that this
     does not replicate cross-database statements such as `UPDATE
     SOME_DB.SOME_TABLE SET foo='bar'' while having selected a
     different database or no database.

     *Warning*:

     To specify multiple databases you _must_ use multiple instances of
     this option. Because database names can contain commas, if you
     supply a comma separated list then the list will be treated as the
     name of a single database.

     An example of what does not work as you might expect: If the slave
     is started with `--replicate-do-db=sales' and you issue the
     following statements on the master, the *Note `UPDATE': update.
     statement is _not_ replicated:

          USE prices;
          UPDATE sales.january SET amount=amount+1000;

     The main reason for this `check just the default database'
     behavior is that it is difficult from the statement alone to know
     whether it should be replicated (for example, if you are using
     multiple-table *Note `DELETE': delete. or multiple-table *Note
     `UPDATE': update. statements that go across multiple databases).
     It is also faster to check only the default database rather than
     all databases if there is no need.

     If you need cross-database updates to work, use
     `--replicate-wild-do-table=DB_NAME.%' instead. See *Note
     replication-rules::.

     Beginning with MySQL 5.0.84, this option has no effect on *Note
     `BEGIN': commit, *Note `COMMIT': commit, or *Note `ROLLBACK':
     commit.  statements. (Bug #43263)

   *  `--replicate-ignore-db=DB_NAME'

     Options for replicate-ignore-db      *Command-Line        `--replicate-ignore-db=name'        
     Format*                              
     *Option-File Format* `replicate-ignore-db'        
                          *Permitted        
                          Values          
                          *               
     *Type*               `string'        


     Tells the slave SQL thread not to replicate any statement where
     the default database (that is, the one selected by *Note `USE':
     use.) is DB_NAME. To specify more than one database to ignore, use
     this option multiple times, once for each database. You should not
     use this option if you are using cross-database updates and you do
     not want these updates to be replicated. See *Note
     replication-rules::.

     An example of what does not work as you might expect: If the slave
     is started with `--replicate-ignore-db=sales' and you issue the
     following statements on the master, the *Note `UPDATE': update.
     statement _is_ replicated:

          USE prices;
          UPDATE sales.january SET amount=amount+1000;

     *Note*:

     In the preceding example the statement is replicated because
     `--replicate-ignore-db' only applies to the default database (set
     through the *Note `USE': use. statement). Because the `sales'
     database was specified explicitly in the statement, the statement
     has not been filtered.

     If you need cross-database updates to work, use
     `--replicate-wild-ignore-table=DB_NAME.%' instead. See *Note
     replication-rules::.

     Beginning with MySQL 5.0.84, this option has no effect on *Note
     `BEGIN': commit, *Note `COMMIT': commit, or *Note `ROLLBACK':
     commit.  statements. (Bug #43263)

   *  `--replicate-do-table=DB_NAME.TBL_NAME'

     Options for replicate-do-table      *Command-Line        `--replicate-do-table=name'        
     Format*                              
     *Option-File Format* `replicate-do-table'        
                          *Permitted        
                          Values          
                          *               
     *Type*               `string'        


     Tells the slave SQL thread to restrict replication to the
     specified table. To specify more than one table, use this option
     multiple times, once for each table. This works for both
     cross-database updates and default database updates, in contrast
     to `--replicate-do-db'.  See *Note replication-rules::.

     This option affects only statements that apply to tables. It does
     not affect statements that apply only to other database objects,
     such as stored routines. To filter statements operating on stored
     routines, use one or more of the `--replicate-*-db' options.

   *  `--replicate-ignore-table=DB_NAME.TBL_NAME'

     Options for replicate-ignore-table      *Command-Line        `--replicate-ignore-table=name'        
     Format*                              
     *Option-File Format* `replicate-ignore-table'        
                          *Permitted        
                          Values          
                          *               
     *Type*               `string'        


     Tells the slave SQL thread not to replicate any statement that
     updates the specified table, even if any other tables might be
     updated by the same statement. To specify more than one table to
     ignore, use this option multiple times, once for each table. This
     works for cross-database updates, in contrast to
     `--replicate-ignore-db'. See *Note replication-rules::.

     This option affects only statements that apply to tables. It does
     not affect statements that apply only to other database objects,
     such as stored routines. To filter statements operating on stored
     routines, use one or more of the `--replicate-*-db' options.

   *  `--replicate-rewrite-db=FROM_NAME->TO_NAME'

     Options for replicate-rewrite-db      *Command-Line        `--replicate-rewrite-db=old_name->new_name'        
     Format*                              
     *Option-File Format* `replicate-rewrite-db'        
                          *Permitted        
                          Values          
                          *               
     *Type*               `string'        


     Tells the slave to translate the default database (that is, the
     one selected by *Note `USE': use.) to TO_NAME if it was FROM_NAME
     on the master. Only statements involving tables are affected (not
     statements such as *Note `CREATE DATABASE': create-database, *Note
     `DROP DATABASE': drop-database, and *Note `ALTER DATABASE':
     alter-database.), and only if FROM_NAME is the default database on
     the master. This does not work for cross-database updates.  To
     specify multiple rewrites, use this option multiple times.  The
     server uses the first one with a FROM_NAME value that matches. The
     database name translation is done _before_ the `--replicate-*'
     rules are tested.

     If you use this option on the command line and the ``>'' character
     is special to your command interpreter, quote the option value.
     For example:

          shell> mysqld --replicate-rewrite-db="OLDDB->NEWDB"

   *  `--replicate-same-server-id'

     Options for replicate-same-server-id      *Version Introduced* 5.0.1           
     *Command-Line        `--replicate-same-server-id'        
     Format*                              
     *Option-File Format* `replicate-same-server-id'        
                          *Permitted        
                          Values          
                          *               
     *Type*               `boolean'        
     *Default*            `FALSE'         


     To be used on slave servers. Usually you should use the default
     setting of 0, to prevent infinite loops caused by circular
     replication. If set to 1, the slave does not skip events having
     its own server ID. Normally, this is useful only in rare
     configurations. Cannot be set to 1 if `--log-slave-updates' is
     used. By default, the slave I/O thread does not write binary log
     events to the relay log if they have the slave's server ID (this
     optimization helps save disk usage). If you want to use
     `--replicate-same-server-id', be sure to start the slave with this
     option before you make the slave read its own events that you want
     the slave SQL thread to execute.

   *  `--replicate-wild-do-table=DB_NAME.TBL_NAME'

     Options for replicate-wild-do-table      *Command-Line        `--replicate-wild-do-table=name'        
     Format*                              
     *Option-File Format* `replicate-wild-do-table'        
                          *Permitted        
                          Values          
                          *               
     *Type*               `string'        


     Tells the slave thread to restrict replication to statements where
     any of the updated tables match the specified database and table
     name patterns. Patterns can contain the ``%'' and ``_'' wildcard
     characters, which have the same meaning as for the `LIKE'
     pattern-matching operator.  To specify more than one table, use
     this option multiple times, once for each table. This works for
     cross-database updates. See *Note replication-rules::.

     This option applies to tables, views, and triggers. It does not
     apply to stored procedures and functions. To filter statements
     operating on the latter objects, use one or more of the
     `--replicate-*-db' options.

     Example: `--replicate-wild-do-table=foo%.bar%' replicates only
     updates that use a table where the database name starts with `foo'
     and the table name starts with `bar'.

     If the table name pattern is `%', it matches any table name and
     the option also applies to database-level statements (*Note
     `CREATE DATABASE': create-database, *Note `DROP DATABASE':
     drop-database, and *Note `ALTER DATABASE': alter-database.). For
     example, if you use `--replicate-wild-do-table=foo%.%',
     database-level statements are replicated if the database name
     matches the pattern `foo%'.

     To include literal wildcard characters in the database or table
     name patterns, escape them with a backslash. For example, to
     replicate all tables of a database that is named `my_own%db', but
     not replicate tables from the `my1ownAABCdb' database, you should
     escape the ``_'' and ``%'' characters like this:
     `--replicate-wild-do-table=my\_own\%db'.  If you use the option on
     the command line, you might need to double the backslashes or
     quote the option value, depending on your command interpreter. For
     example, with the `bash' shell, you would need to type
     `--replicate-wild-do-table=my\\_own\\%db'.

   *  `--replicate-wild-ignore-table=DB_NAME.TBL_NAME'

     Options for replicate-wild-ignore-table      *Command-Line        `--replicate-wild-ignore-table=name'        
     Format*                              
     *Option-File Format* `replicate-wild-ignore-table'        
                          *Permitted        
                          Values          
                          *               
     *Type*               `string'        


     Tells the slave thread not to replicate a statement where any
     table matches the given wildcard pattern. To specify more than one
     table to ignore, use this option multiple times, once for each
     table. This works for cross-database updates. See *Note
     replication-rules::.

     Example: `--replicate-wild-ignore-table=foo%.bar%' does not
     replicate updates that use a table where the database name starts
     with `foo' and the table name starts with `bar'.

     For information about how matching works, see the description of
     the `--replicate-wild-do-table' option. The rules for including
     literal wildcard characters in the option value are the same as for
     `--replicate-wild-ignore-table' as well.

   *  `--report-host=HOST_NAME'

     Options for report-host      *Command-Line        `--report-host=host_name'        
     Format*                              
     *Option-File Format* `report-host'        
     *Option Sets         Yes,            
     Variable*            `report_host'        
                          (http://dev.mysql.com/doc/refman/5.1/en/server-system-variables.html#sysvar_report_host)        
     *Variable Name*      `report-host'        
     *Variable Scope*     Global          
     *Dynamic Variable*   No              
                          *Permitted        
                          Values          
                          *               
     *Type*               `string'        


     The host name or IP address of the slave to be reported to the
     master during slave registration. This value appears in the output
     of *Note `SHOW SLAVE HOSTS': show-slave-hosts. on the master
     server. Leave the value unset if you do not want the slave to
     register itself with the master. Note that it is not sufficient
     for the master to simply read the IP address of the slave from the
     TCP/IP socket after the slave connects. Due to NAT and other
     routing issues, that IP may not be valid for connecting to the
     slave from the master or other hosts.

   *  `--report-password=PASSWORD'

     Options for report-password      *Command-Line        `--report-password=name'        
     Format*                              
     *Option-File Format* `report-password'        
     *Option Sets         Yes,            
     Variable*            `report_password'        
                          (http://dev.mysql.com/doc/refman/5.1/en/server-system-variables.html#sysvar_report_password)        
     *Variable Name*      `report-password'        
     *Variable Scope*     Global          
     *Dynamic Variable*   No              
                          *Permitted        
                          Values          
                          *               
     *Type*               `string'        


     The account password of the slave to be reported to the master
     during slave registration. This value appears in the output of
     *Note `SHOW SLAVE HOSTS': show-slave-hosts. on the master server
     if the `--show-slave-auth-info' option is given.

     Although the name of this option might imply otherwise,
     `--report-password' is not connected to the MySQL user privilege
     system and so is not necessarily (or even likely to be) the same
     as the password for the MySQL replication user account.

   *  `--report-port=SLAVE_PORT_NUM'

     Options for report-port      *Command-Line        `--report-port=#'        
     Format*                              
     *Option-File Format* `report-port'        
     *Option Sets         Yes,            
     Variable*            `report_port'        
                          (http://dev.mysql.com/doc/refman/5.1/en/server-system-variables.html#sysvar_report_port)        
     *Variable Name*      `report-port'        
     *Variable Scope*     Global          
     *Dynamic Variable*   No              
                          *Permitted        
                          Values          
                          *               
     *Type*               `numeric'        
     *Default*            `3306'          


     The TCP/IP port number for connecting to the slave, to be reported
     to the master during slave registration. Set this only if the
     slave is listening on a nondefault port or if you have a special
     tunnel from the master or other clients to the slave. If you are
     not sure, do not use this option.

   *  `--report-user=USER_NAME'

     Options for report-user      *Command-Line        `--report-user=name'        
     Format*                              
     *Option-File Format* `report-user'        
     *Option Sets         Yes,            
     Variable*            `report_user'        
                          (http://dev.mysql.com/doc/refman/5.1/en/server-system-variables.html#sysvar_report_user)        
     *Variable Name*      `report-user'        
     *Variable Scope*     Global          
     *Dynamic Variable*   No              
                          *Permitted        
                          Values          
                          *               
     *Type*               `string'        


     The account user name of the slave to be reported to the master
     during slave registration. This value appears in the output of
     *Note `SHOW SLAVE HOSTS': show-slave-hosts. on the master server
     if the `--show-slave-auth-info' option is given.

     Although the name of this option might imply otherwise,
     `--report-user' is not connected to the MySQL user privilege
     system and so is not necessarily (or even likely to be) the same
     as the name of the MySQL replication user account.

   *  `--show-slave-auth-info'

     Options for show-slave-auth-info      *Command-Line        `--show-slave-auth-info'        
     Format*                              
     *Option-File Format* `show-slave-auth-info'        
                          *Permitted        
                          Values          
                          *               
     *Type*               `boolean'        
     *Default*            `FALSE'         


     Display slave user names and passwords in the output of *Note
     `SHOW SLAVE HOSTS': show-slave-hosts. on the master server for
     slaves started with the `--report-user' and `--report-password'
     options.

   *  `--skip-slave-start'

     Options for skip-slave-start      *Command-Line        `--skip-slave-start'        
     Format*                              
     *Option-File Format* `skip-slave-start'        
                          *Permitted        
                          Values          
                          *               
     *Type*               `boolean'        
     *Default*            `FALSE'         


     Tells the slave server not to start the slave threads when the
     server starts. To start the threads later, use a *Note `START
     SLAVE': start-slave. statement.

   *  `--slave_compressed_protocol={0|1}'

     Options for slave_compressed_protocol      *Command-Line        `--slave_compressed_protocol'        
     Format*                              
     *Option-File Format* `slave_compressed_protocol'        
     *Option Sets         Yes,            
     Variable*            `slave_compressed_protocol'        
     *Variable Name*      `slave_compressed_protocol'        
     *Variable Scope*     Global          
     *Dynamic Variable*   Yes             
                          *Permitted        
                          Values          
                          *               
     *Type*               `boolean'        
     *Default*            `OFF'           


     If this option is set to 1, use compression for the slave/master
     protocol if both the slave and the master support it. The default
     is 0 (no compression).

   *  `--slave-load-tmpdir=FILE_NAME'

     The name of the directory where the slave creates temporary files.
     This option is by default equal to the value of the `tmpdir'
     system variable. When the slave SQL thread replicates a *Note
     `LOAD DATA INFILE': load-data. statement, it extracts the file to
     be loaded from the relay log into temporary files, and then loads
     these into the table. If the file loaded on the master is huge, the
     temporary files on the slave are huge, too. Therefore, it might be
     advisable to use this option to tell the slave to put temporary
     files in a directory located in some file system that has a lot of
     available space. In that case, the relay logs are huge as well, so
     you might also want to use the `--relay-log' option to place the
     relay logs in that file system.

     The directory specified by this option should be located in a
     disk-based file system (not a memory-based file system) because
     the temporary files used to replicate *Note `LOAD DATA INFILE':
     load-data. must survive machine restarts. The directory also
     should not be one that is cleared by the operating system during
     the system startup process.

   *  `--slave-net-timeout=SECONDS'

     Options for slave-net-timeout      *Command-Line        `--slave-net-timeout=#'        
     Format*                              
     *Option-File Format* `slave-net-timeout'        
     *Option Sets         Yes,            
     Variable*            `slave_net_timeout'        
     *Variable Name*      `slave_net_timeout'        
     *Variable Scope*     Global          
     *Dynamic Variable*   Yes             
                          *Permitted        
                          Values          
                          *               
     *Type*               `numeric'        
     *Default*            `3600'          
     *Min Value*          `1'             


     The number of seconds to wait for more data from the master before
     the slave considers the connection broken, aborts the read, and
     tries to reconnect. The first retry occurs immediately after the
     timeout. The interval between retries is controlled by the *Note
     `CHANGE MASTER TO': change-master-to. statement or
     `--master-connect-retry' option and the number of reconnection
     attempts is limited by the `--master-retry-count' option.  The
     default is 3600 seconds (one hour).

   *  `--slave-skip-errors=[ERR_CODE1,ERR_CODE2,...|all]'

     Options for slave-skip-errors      *Command-Line        `--slave-skip-errors=name'        
     Format*                              
     *Option-File Format* `slave-skip-errors'        
     *Option Sets         Yes,            
     Variable*            `slave_skip_errors'        
     *Variable Name*      `slave_skip_errors'        
     *Variable Scope*     Global          
     *Dynamic Variable*   No              


     Normally, replication stops when an error occurs on the slave.
     This gives you the opportunity to resolve the inconsistency in the
     data manually. This option tells the slave SQL thread to continue
     replication when a statement returns any of the errors listed in
     the option value.

     Do not use this option unless you fully understand why you are
     getting errors. If there are no bugs in your replication setup and
     client programs, and no bugs in MySQL itself, an error that stops
     replication should never occur. Indiscriminate use of this option
     results in slaves becoming hopelessly out of synchrony with the
     master, with you having no idea why this has occurred.

     For error codes, you should use the numbers provided by the error
     message in your slave error log and in the output of *Note `SHOW
     SLAVE STATUS': show-slave-status.  *Note error-handling::, lists
     server error codes.

     You can also (but should not) use the very nonrecommended value of
     `all' to cause the slave to ignore all error messages and keeps
     going regardless of what happens.  Needless to say, if you use
     `all', there are no guarantees regarding the integrity of your
     data. Please do not complain (or file bug reports) in this case if
     the slave's data is not anywhere close to what it is on the master.
     _You have been warned_.

     Examples:

          --slave-skip-errors=1062,1053
          --slave-skip-errors=all

System variables used on replication slaves

The following list describes system variables for controlling
replication slave servers. They can be set at server startup and some
of them can be changed at runtime using *Note `SET': set-option.
Server options used with replication slaves are listed earlier in this
section.

   *  `init_slave'

     Options for init_slave      *Command-Line        `--init-slave=name'        
     Format*                              
     *Option-File Format* `init_slave'        
     *Option Sets         Yes,            
     Variable*            `init_slave'        
     *Variable Name*      `init_slave'        
     *Variable Scope*     Global          
     *Dynamic Variable*   Yes             
                          *Permitted        
                          Values          
                          *               
     *Type*               `string'        


     This variable is similar to `init_connect', but is a string to be
     executed by a slave server each time the SQL thread starts. The
     format of the string is the same as for the `init_connect'
     variable.

     *Note*:

     The SQL thread sends an acknowledgment to the client before it
     executes `init_slave'.  Therefore, it is not guaranteed that
     `init_slave' has been executed when *Note `START SLAVE':
     start-slave.  returns. See *Note start-slave::, for more
     information.

   *  `relay_log_index'

     Options for relay_log_index      *Command-Line        `--relay-log-index'        
     Format*                              
     *Option-File Format* `relay_log_index'        
     *Option Sets         Yes,            
     Variable*            `relay_log_index'        
     *Variable Name*      `relay_log_index'        
     *Variable Scope*     Global          
     *Dynamic Variable*   No              
                          *Permitted        
                          Values          
                          *               
     *Type*               `string'        
     *Default*            `*host_name*-relay-bin.index'        


     The name of the relay log index file. The default name is
     `HOST_NAME-relay-bin.index' in the data directory, where HOST_NAME
     is the name of the slave server.

   *  `relay_log_info_file'

     Options for relay_log_info_file      *Command-Line        `--relay-log-info-file=file_name'        
     Format*                              
     *Option-File Format* `relay_log_info_file'        
     *Option Sets         Yes,            
     Variable*            `relay_log_info_file'        
     *Variable Name*      `relay_log_info_file'        
     *Variable Scope*     Global          
     *Dynamic Variable*   No              
                          *Permitted        
                          Values          
                          *               
     *Type*               `string'        
     *Default*            `relay-log.info'        


     The name of the file in which the slave records information about
     the relay logs. The default name is `relay-log.info' in the data
     directory.

   *  `rpl_recovery_rank'

     This variable is unused, and is removed in MySQL 5.6.

   *  `slave_compressed_protocol'

     Options for slave_compressed_protocol      *Command-Line        `--slave_compressed_protocol'        
     Format*                              
     *Option-File Format* `slave_compressed_protocol'        
     *Option Sets         Yes,            
     Variable*            `slave_compressed_protocol'        
     *Variable Name*      `slave_compressed_protocol'        
     *Variable Scope*     Global          
     *Dynamic Variable*   Yes             
                          *Permitted        
                          Values          
                          *               
     *Type*               `boolean'        
     *Default*            `OFF'           


     Whether to use compression of the slave/master protocol if both
     the slave and the master support it.

   *  `slave_load_tmpdir'

     Options for slave-load-tmpdir      *Command-Line        `--slave-load-tmpdir=path'        
     Format*                              
     *Option-File Format* `slave-load-tmpdir'        
     *Option Sets         Yes,            
     Variable*            `slave_load_tmpdir'        
     *Variable Name*      `slave_load_tmpdir'        
     *Variable Scope*     Global          
     *Dynamic Variable*   No              
                          *Permitted        
                          Values          
                          *               
     *Type*               `file           
                          name'           
     *Default*            `/tmp'          


     The name of the directory where the slave creates temporary files
     for replicating *Note `LOAD DATA INFILE': load-data. statements.

   *  `slave_net_timeout'

     Options for slave-net-timeout      *Command-Line        `--slave-net-timeout=#'        
     Format*                              
     *Option-File Format* `slave-net-timeout'        
     *Option Sets         Yes,            
     Variable*            `slave_net_timeout'        
     *Variable Name*      `slave_net_timeout'        
     *Variable Scope*     Global          
     *Dynamic Variable*   Yes             
                          *Permitted        
                          Values          
                          *               
     *Type*               `numeric'        
     *Default*            `3600'          
     *Min Value*          `1'             


     The number of seconds to wait for more data from a master/slave
     connection before aborting the read. This timeout applies only to
     TCP/IP connections, not to connections made using Unix socket
     files, named pipes, or shared memory.

   *  `slave_skip_errors'

     Options for slave-skip-errors      *Command-Line        `--slave-skip-errors=name'        
     Format*                              
     *Option-File Format* `slave-skip-errors'        
     *Option Sets         Yes,            
     Variable*            `slave_skip_errors'        
     *Variable Name*      `slave_skip_errors'        
     *Variable Scope*     Global          
     *Dynamic Variable*   No              


     Normally, replication stops when an error occurs on the slave.
     This gives you the opportunity to resolve the inconsistency in the
     data manually. This variable tells the slave SQL thread to
     continue replication when a statement returns any of the errors
     listed in the variable value.

   *  `slave_transaction_retries'

     Options for slave_transaction_retries      *Version Introduced* 5.0.3           
     *Command-Line        `--slave_transaction_retries=#'        
     Format*                              
     *Option-File Format* `slave_transaction_retries'        
     *Option Sets         Yes,            
     Variable*            `slave_transaction_retries'        
     *Variable Name*      `slave_transaction_retries'        
     *Variable Scope*     Global          
     *Dynamic Variable*   Yes             
                          *Permitted        
                          Values          
                          *               
     *Platform Bit Size*  `32'            
     *Type*               `numeric'        
     *Default*            `10'            
     *Range*              `0 ..           
                          4294967295'        
                          *Permitted        
                          Values          
                          *               
     *Platform Bit Size*  `64'            
     *Type*               `numeric'        
     *Default*            `10'            
     *Range*              `0 ..           
                          18446744073709547520'        


     If a replication slave SQL thread fails to execute a transaction
     because of an *Note `InnoDB': innodb-storage-engine.  deadlock or
     because the transaction's execution time exceeded *Note `InnoDB':
     innodb-storage-engine.'s `innodb_lock_wait_timeout' or *Note
     `NDBCLUSTER': mysql-cluster.'s
     `TransactionDeadlockDetectionTimeout' or
     `TransactionInactiveTimeout', it automatically retries
     `slave_transaction_retries' times before stopping with an error.
     Prior to MySQL 5.0.3, the default is 0, and you must explicitly
     set the value greater than 0 to enable the `retry' behavior. In
     MySQL 5.0.3 or newer, the default is 10.

   *  `sql_slave_skip_counter'

     Options for sql_slave_skip_counter      *Variable Name*      `sql_slave_skip_counter'        
     *Variable Scope*     Global          
     *Dynamic Variable*   Yes             
                          *Permitted        
                          Values          
                          *               
     *Type*               `numeric'        


     The number of events from the master that a slave server should
     skip.

     *Important*:

     If skipping the number of events specified by setting this
     variable would cause the slave to begin in the middle of an event
     group, the slave continues to skip until it finds the beginning of
     the next event group and begins from that point. For more
     information, see *Note set-global-sql-slave-skip-counter::.


File: manual.info,  Node: replication-options-binary-log,  Prev: replication-options-slave,  Up: replication-options

16.1.2.4 Binary Log Options and Variables
.........................................

You can use the *Note `mysqld': mysqld. options and system variables
that are described in this section to affect the operation of the
binary log as well as to control which statements are written to the
binary log. For additional information about the binary log, see *Note
binary-log::. For additional information about using MySQL server
options and system variables, see *Note server-options::, and *Note
server-system-variables::.

Startup options used with binary logging

The following list describes startup options for enabling and
configuring the binary log. System variables used with binary logging
are discussed later in this section.

   *  `--log-bin[=BASE_NAME]'

     Options for log-bin      *Command-Line        `--log-bin'        
     Format*                              
     *Option-File Format* `log-bin'        
     *Variable Name*      `log_bin'        
     *Variable Scope*     Global          
     *Dynamic Variable*   No              
                          *Permitted        
                          Values          
                          *               
     *Type*               `file           
                          name'           
     *Default*            `OFF'           


     Enable binary logging. The server logs all statements that change
     data to the binary log, which is used for backup and replication.
     See *Note binary-log::.

     The option value, if given, is the basename for the log sequence.
     The server creates binary log files in sequence by adding a
     numeric suffix to the basename. It is recommended that you specify
     a basename (see *Note bugs::, for the reason). Otherwise, MySQL
     uses `HOST_NAME-bin' as the basename.

     Setting this option causes the `log_bin' system variable to be set
     to `ON' (or `1'), and not to the basename. This is a known issue;
     see Bug #19614 for more information.

   *  `--log-bin-index[=FILE_NAME]'

     Options for log-bin-index      *Command-Line        `--log-bin-index=name'        
     Format*                              
     *Option-File Format* `log-bin-index'        
                          *Permitted        
                          Values          
                          *               
     *Type*               `file           
                          name'           
     *Default*            `OFF'           


     The index file for binary log file names. See *Note binary-log::.
     If you omit the file name, and if you did not specify one with
     `--log-bin', MySQL uses `HOST_NAME-bin.index' as the file name.

   *  `--log-bin-trust-function-creators[={0|1}]'

     Options for log-bin-trust-function-creators      *Version Introduced* 5.0.16          
     *Command-Line        `--log-bin-trust-function-creators'        
     Format*                              
     *Option-File Format* `log-bin-trust-function-creators'        
     *Option Sets         Yes,            
     Variable*            `log_bin_trust_function_creators'        
     *Variable Name*      `log_bin_trust_function_creators'        
     *Variable Scope*     Global          
     *Dynamic Variable*   Yes             
                          *Permitted        
                          Values          
                          *               
     *Type*               `boolean'        
     *Default*            `FALSE'         


     This option sets the corresponding
     `log_bin_trust_function_creators' system variable. If no argument
     is given, the option sets the variable to 1.
     `log_bin_trust_function_creators' affects how MySQL enforces
     restrictions on stored function and trigger creation. See *Note
     stored-programs-logging::.

     This option was added in MySQL 5.0.16.

   *  `--log-bin-trust-routine-creators[={0|1}]'

     Options for log-bin-trust-routine-creators      *Version Introduced* 5.0.6           
     *Version Deprecated* 5.0.16          
     *Command-Line        `--log-bin-trust-routine-creators'        
     Format*                              
     *Option-File Format* `log-bin-trust-routine-creators'        
     *Option Sets         Yes,            
     Variable*            `log_bin_trust_routine_creators'        
     *Variable Name*      `log-bin-trust-routine-creators'        
     *Variable Scope*     Global          
     *Dynamic Variable*   Yes             
     *Deprecated*         5.0.16,         
                          by              
                          `log-bin-trust-function-creators'        
                          *Permitted        
                          Values          
                          *               
     *Type*               `boolean'        
     *Default*            `FALSE'         


     This is the old name for `--log-bin-trust-function-creators'.
     Before MySQL 5.0.16, it also applies to stored procedures, not
     just stored functions and sets the
     `log_bin_trust_routine_creators' system variable. As of 5.0.16,
     this option is deprecated. It is recognized for backward
     compatibility but its use results in a warning.

     This option was added in MySQL 5.0.6.

Statement selection options

The options in the following list affect which statements are written
to the binary log, and thus sent by a replication master server to its
slaves. There are also options for slave servers that control which
statements received from the master should be executed or ignored. For
details, see *Note replication-options-slave::.

   *  `--binlog-do-db=DB_NAME'

     Options for binlog-do-db      *Command-Line        `--binlog-do-db=name'        
     Format*                              
     *Option-File Format* `binlog-do-db'        
                          *Permitted        
                          Values          
                          *               
     *Type*               `string'        


     This option affects binary logging in a manner similar to the way
     that `--replicate-do-db' affects replication.

     Tell the server to restrict binary logging to updates for which
     the default database is DB_NAME (that is, the database selected by
     *Note `USE': use.). All other databases that are not explicitly
     mentioned are ignored. If you use this option, you should ensure
     that you do updates only in the default database.

     There is an exception to this for *Note `CREATE DATABASE':
     create-database, *Note `ALTER DATABASE': alter-database, and *Note
     `DROP DATABASE': drop-database. statements. The server uses the
     database named in the statement (not the default database) to
     decide whether it should log the statement.

     An example of what does not work as you might expect: If the
     server is started with `--binlog-do-db=sales' and you issue the
     following statements, the *Note `UPDATE': update. statement is
     _not_ logged:

          USE prices;
          UPDATE sales.january SET amount=amount+1000;

     The main reason for this `just check the default database'
     behavior is that it is difficult from the statement alone to know
     whether it should be replicated (for example, if you are using
     multiple-table *Note `DELETE': delete. statements or
     multiple-table *Note `UPDATE': update.  statements that act across
     multiple databases). It is also faster to check only the default
     database rather than all databases if there is no need.

     Another case which may not be self-evident occurs when a given
     database is replicated even though it was not specified when
     setting the option. If the server is started with
     `--binlog-do-db=sales', the following *Note `UPDATE': update.
     statement is logged even though `prices' was not included when
     setting `--binlog-do-db':


          USE sales;
          UPDATE prices.discounts SET percentage = percentage + 10;

     Because `sales' is the default database when the *Note `UPDATE':
     update. statement is issued, the *Note `UPDATE': update. is logged.

     *Important*:

     To log multiple databases, use this option multiple times,
     specifying the option once for each database to be logged.
     Because database names can contain commas, the list will be
     treated as the name of a single database if you supply a
     comma-separated list.

   *  `--binlog-ignore-db=DB_NAME'

     Options for binlog-ignore-db      *Command-Line        `--binlog-ignore-db=name'        
     Format*                              
     *Option-File Format* `binlog-ignore-db'        
                          *Permitted        
                          Values          
                          *               
     *Type*               `string'        


     This option affects binary logging in a manner similar to the way
     that `--replicate-ignore-db' affects replication.

     Tell the server to suppress binary logging of updates for which
     the default database is DB_NAME (that is, the database selected by
     *Note `USE': use.). If you use this option, you should ensure that
     you do updates only in the default database.

     As with the `--binlog-do-db' option, there is an exception for the
     *Note `CREATE DATABASE': create-database, *Note `ALTER DATABASE':
     alter-database, and *Note `DROP DATABASE': drop-database.
     statements. The server uses the database named in the statement
     (not the default database) to decide whether it should log the
     statement.

     An example of what does not work as you might expect: If the
     server is started with `binlog-ignore-db=sales', and you run `USE
     prices; UPDATE sales.january SET amount = amount + 1000;', this
     statement _is_ written into the binary log.

     *Important*:

     To ignore multiple databases, use this option multiple times,
     specifying the option once for each database to be ignored.
     Because database names can contain commas, the list will be
     treated as the name of a single database if you supply a
     comma-separated list.

Testing and debugging options

The following binary log options are used in replication testing and
debugging. They are not intended for use in normal operations.

   *  `--max-binlog-dump-events=N'

     Options for max-binlog-dump-events      *Command-Line        `--max-binlog-dump-events=#'        
     Format*                              
     *Option-File Format* `max-binlog-dump-events'        
                          *Permitted        
                          Values          
                          *               
     *Type*               `numeric'        
     *Default*            `0'             


     This option is used internally by the MySQL test suite for
     replication testing and debugging.

   *  `--sporadic-binlog-dump-fail'

     Options for sporadic-binlog-dump-fail      *Command-Line        `--sporadic-binlog-dump-fail'        
     Format*                              
     *Option-File Format* `sporadic-binlog-dump-fail'        
                          *Permitted        
                          Values          
                          *               
     *Type*               `boolean'        
     *Default*            `FALSE'         


     This option is used internally by the MySQL test suite for
     replication testing and debugging.

System variables used with the binary log

The following list describes system variables for controlling binary
logging. They can be set at server startup and some of them can be
changed at runtime using *Note `SET': set-option.  Server options used
to control binary logging are listed earlier in this section.

   *  `log_slave_updates'

     Whether updates received by a slave server from a master server
     should be logged to the slave's own binary log. Binary logging
     must be enabled on the slave for this variable to have any effect.
     See *Note replication-options-slave::.

   *  `max_binlog_cache_size'

     Options for max_binlog_cache_size      *Command-Line        `--max_binlog_cache_size=#'        
     Format*                              
     *Option-File Format* `max_binlog_cache_size'        
     *Option Sets         Yes,            
     Variable*            `max_binlog_cache_size'        
     *Variable Name*      `max_binlog_cache_size'        
     *Variable Scope*     Global          
     *Dynamic Variable*   Yes             


     If a multiple-statement transaction requires more than this many
     bytes of memory, the server generates a `Multi-statement
     transaction required more than 'max_binlog_cache_size' bytes of
     storage' error.  The minimum value is 4096. The maximum and
     default values are 4GB on 32-bit platforms and 16PB (petabytes) on
     64-bit platforms.

     In MySQL 5.0, a change in `max_binlog_cache_size' takes immediate
     effect for all active sessions.

   *  `max_binlog_size'

     Options for max_binlog_size      *Command-Line        `--max_binlog_size=#'        
     Format*                              
     *Option-File Format* `max_binlog_size'        
     *Option Sets         Yes,            
     Variable*            `max_binlog_size'        
     *Variable Name*      `max_binlog_size'        
     *Variable Scope*     Global          
     *Dynamic Variable*   Yes             
                          *Permitted        
                          Values          
                          *               
     *Type*               `numeric'        
     *Default*            `1073741824'        
     *Range*              `4096           
                          ..              
                          1073741824'        


     If a write to the binary log causes the current log file size to
     exceed the value of this variable, the server rotates the binary
     logs (closes the current file and opens the next one).  The
     minimum value is 4096 bytes. The maximum and default value is 1GB.

     A transaction is written in one chunk to the binary log, so it is
     never split between several binary logs. Therefore, if you have
     big transactions, you might see binary log files larger than
     `max_binlog_size'.

     If `max_relay_log_size' is 0, the value of `max_binlog_size'
     applies to relay logs as well.

   *  `sync_binlog'

     Options for sync_binlog      *Version Introduced* 5.0.1           
     *Command-Line        `--sync-binlog=#'        
     Format*                              
     *Option-File Format* `sync_binlog'        
     *Option Sets         Yes,            
     Variable*            `sync_binlog'        
     *Variable Name*      `sync_binlog'        
     *Variable Scope*     Global          
     *Dynamic Variable*   Yes             
                          *Permitted        
                          Values          
                          *               
     *Platform Bit Size*  `32'            
     *Type*               `numeric'        
     *Default*            `0'             
     *Range*              `0 ..           
                          4294967295'        
                          *Permitted        
                          Values          
                          *               
     *Platform Bit Size*  `64'            
     *Type*               `numeric'        
     *Default*            `0'             
     *Range*              `0 ..           
                          18446744073709547520'        


     If the value of this variable is greater than 0, the MySQL server
     synchronizes its binary log to disk (using `fdatasync()') after
     every `sync_binlog' writes to the binary log. There is one write
     to the binary log per statement if autocommit is enabled, and one
     write per transaction otherwise. The default value of
     `sync_binlog' is 0, which does no synchronizing to disk. A value
     of 1 is the safest choice because in the event of a crash you lose
     at most one statement or transaction from the binary log. However,
     it is also the slowest choice (unless the disk has a
     battery-backed cache, which makes synchronization very fast).

     If the value of `sync_binlog' is 0 (the default), no extra
     flushing is done. The server relies on the operating system to
     flush the file contents occasionally as for any other file.


File: manual.info,  Node: replication-administration,  Prev: replication-options,  Up: replication-configuration

16.1.3 Common Replication Administration Tasks
----------------------------------------------

* Menu:

* replication-administration-status::  Checking Replication Status
* replication-administration-pausing::  Pausing Replication on the Slave

Once replication has been started it should execute without requiring
much regular administration. Depending on your replication environment,
you will want to check the replication status of each slave
periodically, daily, or even more frequently.


File: manual.info,  Node: replication-administration-status,  Next: replication-administration-pausing,  Prev: replication-administration,  Up: replication-administration

16.1.3.1 Checking Replication Status
....................................

The most common task when managing a replication process is to ensure
that replication is taking place and that there have been no errors
between the slave and the master. The primary statement for this is
*Note `SHOW SLAVE STATUS': show-slave-status, which you must execute on
each slave:

     mysql> SHOW SLAVE STATUS\G
     *************************** 1. row ***************************
                  Slave_IO_State: Waiting for master to send event
                     Master_Host: master1
                     Master_User: root
                     Master_Port: 3306
                   Connect_Retry: 60
                 Master_Log_File: mysql-bin.000004
             Read_Master_Log_Pos: 931
                  Relay_Log_File: slave1-relay-bin.000056
                   Relay_Log_Pos: 950
           Relay_Master_Log_File: mysql-bin.000004
                Slave_IO_Running: Yes
               Slave_SQL_Running: Yes
                 Replicate_Do_DB:
             Replicate_Ignore_DB:
              Replicate_Do_Table:
          Replicate_Ignore_Table:
         Replicate_Wild_Do_Table:
     Replicate_Wild_Ignore_Table:
                      Last_Errno: 0
                      Last_Error:
                    Skip_Counter: 0
             Exec_Master_Log_Pos: 931
                 Relay_Log_Space: 1365
                 Until_Condition: None
                  Until_Log_File:
                   Until_Log_Pos: 0
              Master_SSL_Allowed: No
              Master_SSL_CA_File:
              Master_SSL_CA_Path:
                 Master_SSL_Cert:
               Master_SSL_Cipher:
                  Master_SSL_Key:
           Seconds_Behind_Master: 0

The key fields from the status report to examine are:

   * `Slave_IO_State': The current status of the slave. See *Note
     slave-io-thread-states::, and *Note slave-sql-thread-states::, for
     more information.

   * `Slave_IO_Running': Whether the I/O thread for reading the
     master's binary log is running. Normally, you want this to be
     `Yes' unless you have not yet started replication or have
     explicitly stopped it with *Note `STOP SLAVE': stop-slave.

   * `Slave_SQL_Running': Whether the SQL thread for executing events
     in the relay log is running. As with the I/O thread, this should
     normally be `Yes'.

   * `Last_Error': The last error registered when processing the relay
     log. Ideally this should be blank, indicating no error.

   * `Seconds_Behind_Master': The number of seconds that the slave SQL
     thread is behind processing the master binary log. A high number
     (or an increasing one) can indicate that the slave is unable to
     handle events from the master in a timely fashion.

     A value of 0 for `Seconds_Behind_Master' can usually be
     interpreted as meaning that the slave has caught up with the
     master, but there are some cases where this is not strictly true.
     For example, this can occur if the network connection between
     master and slave is broken but the slave I/O thread has not yet
     noticed this--that is, `slave_net_timeout' has not yet elapsed.

     It is also possible that transient values for
     `Seconds_Behind_Master' may not reflect the situation accurately.
     When the slave SQL thread has caught up on I/O,
     `Seconds_Behind_Master' displays 0; but when the slave I/O thread
     is still queuing up a new event, `Seconds_Behind_Master' may show a
     large value until the SQL thread finishes executing the new event.
     This is especially likely when the events have old timestamps; in
     such cases, if you execute *Note `SHOW SLAVE STATUS':
     show-slave-status. several times in a relatively short period, you
     may see this value change back and forth repeatedly between 0 and
     a relatively large value.

Several pairs of fields provide information about the progress of the
slave in reading events from the master binary log and processing them
in the relay log:

   * (`Master_Log_file', `Read_Master_Log_Pos'): Coordinates in the
     master binary log indicating how far the slave I/O thread has read
     events from that log.

   * (`Relay_Master_Log_File', `Exec_Master_Log_Pos'): Coordinates in
     the master binary log indicating how far the slave SQL thread has
     executed events received from that log.

   * (`Relay_Log_File', `Relay_Log_Pos'): Coordinates in the slave
     relay log indicating how far the slave SQL thread has executed the
     relay log. These correspond to the preceding coordinates, but are
     expressed in slave relay log coordinates rather than master binary
     log coordinates.

On the master, you can check the status of connected slaves using *Note
`SHOW PROCESSLIST': show-processlist. to examine the list of running
processes. Slave connections have `Binlog Dump' in the `Command' field:

     mysql> SHOW PROCESSLIST \G;
     *************************** 4. row ***************************
          Id: 10
        User: root
        Host: slave1:58371
          db: NULL
     Command: Binlog Dump
        Time: 777
       State: Has sent all binlog to slave; waiting for binlog to be updated
        Info: NULL

Because it is the slave that drives the replication process, very
little information is available in this report.

For slaves that were started with the `--report-host' option and are
connected to the master, the *Note `SHOW SLAVE HOSTS':
show-slave-hosts. statement on the master shows basic information about
the slaves. The output includes the ID of the slave server, the value
of the `--report-host' option, the connecting port, and master ID:

     mysql> SHOW SLAVE HOSTS;
     +-----------+--------+------+-------------------+-----------+
     | Server_id | Host   | Port | Rpl_recovery_rank | Master_id |
     +-----------+--------+------+-------------------+-----------+
     |        10 | slave1 | 3306 |                 0 |         1 |
     +-----------+--------+------+-------------------+-----------+
     1 row in set (0.00 sec)


File: manual.info,  Node: replication-administration-pausing,  Prev: replication-administration-status,  Up: replication-administration

16.1.3.2 Pausing Replication on the Slave
.........................................

You can stop and start the replication of statements on the slave using
the *Note `STOP SLAVE': stop-slave. and *Note `START SLAVE':
start-slave. statements.

To stop processing of the binary log from the master, use *Note `STOP
SLAVE': stop-slave.:

     mysql> STOP SLAVE;

When replication is stopped, the slave I/O thread stops reading events
from the master binary log and writing them to the relay log, and the
SQL thread stops reading events from the relay log and executing them.
You can pause the I/O or SQL thread individually by specifying the
thread type:

     mysql> STOP SLAVE IO_THREAD;
     mysql> STOP SLAVE SQL_THREAD;

To start execution again, use the *Note `START SLAVE': start-slave.
statement:

     mysql> START SLAVE;

To start a particular thread, specify the thread type:

     mysql> START SLAVE IO_THREAD;
     mysql> START SLAVE SQL_THREAD;

For a slave that performs updates only by processing events from the
master, stopping only the SQL thread can be useful if you want to
perform a backup or other task. The I/O thread will continue to read
events from the master but they are not executed. This makes it easier
for the slave to catch up when you restart the SQL thread.

Stopping only the I/O thread enables the events in the relay log to be
executed by the SQL thread up to the point where the relay log ends.
This can be useful when you want to pause execution to catch up with
events already received from the master, when you want to perform
administration on the slave but also ensure that it has processed all
updates to a specific point. This method can also be used to pause
event receipt on the slave while you conduct administration on the
master. Stopping the I/O thread but permitting the SQL thread to run
helps ensure that there is not a massive backlog of events to be
executed when replication is started again.


File: manual.info,  Node: replication-implementation,  Next: replication-solutions,  Prev: replication-configuration,  Up: replication

16.2 Replication Implementation
===============================

* Menu:

* replication-implementation-details::  Replication Implementation Details
* slave-logs::                   Replication Relay and Status Logs
* replication-rules::            How Servers Evaluate Replication Filtering Rules

Replication is based on the master server keeping track of all changes
to its databases (updates, deletes, and so on) in its binary log. The
binary log serves as a written record of all events that modify
database structure or content (data) from the moment the server was
started. Typically, *Note `SELECT': select.  statements are not
recorded because they modify neither database structure nor content.

Each slave that connects to the master requests a copy of the binary
log. That is, it pulls the data from the master, rather than the master
pushing the data to the slave. The slave also executes the events from
the binary log that it receives. This has the effect of repeating the
original changes just as they were made on the master.  Tables are
created or their structure modified, and data is inserted, deleted, and
updated according to the changes that were originally made on the
master.

Because each slave is independent, the replaying of the changes from
the master's binary log occurs independently on each slave that is
connected to the master. In addition, because each slave receives a
copy of the binary log only by requesting it from the master, the slave
is able to read and update the copy of the database at its own pace and
can start and stop the replication process at will without affecting
the ability to update to the latest database status on either the
master or slave side.

For more information on the specifics of the replication
implementation, see *Note replication-implementation-details::.

Masters and slaves report their status in respect of the replication
process regularly so that you can monitor them. See *Note
thread-information::, for descriptions of all replicated-related states.

The master binary log is written to a local relay log on the slave
before it is processed. The slave also records information about the
current position with the master's binary log and the local relay log.
See *Note slave-logs::.

Database changes are filtered on the slave according to a set of rules
that are applied according to the various configuration options and
variables that control event evaluation. For details on how these rules
are applied, see *Note replication-rules::.


File: manual.info,  Node: replication-implementation-details,  Next: slave-logs,  Prev: replication-implementation,  Up: replication-implementation

16.2.1 Replication Implementation Details
-----------------------------------------

MySQL replication capabilities are implemented using three threads, one
on the master server and two on the slave:

   * Binlog dump thread

     The master creates a thread to send the binary log contents to a
     slave when the slave connects. This thread can be identified in
     the output of *Note `SHOW PROCESSLIST': show-processlist. on the
     master as the `Binlog Dump' thread.

     The binlog dump thread acquires a lock on the master's binary log
     for reading each event that is to be sent to the slave. As soon as
     the event has been read, the lock is released, even before the
     event is sent to the slave.

   * Slave I/O thread

     When a *Note `START SLAVE': start-slave. statement is issued on a
     slave server, the slave creates an I/O thread, which connects to
     the master and asks it to send the updates recorded in its binary
     logs.

     The slave I/O thread reads the updates that the master's `Binlog
     Dump' thread sends (see previous item) and copies them to local
     files that comprise the slave's relay log.

     The state of this thread is shown as `Slave_IO_running' in the
     output of *Note `SHOW SLAVE STATUS': show-slave-status. or as
     `Slave_running' in the output of *Note `SHOW STATUS': show-status.

   * Slave SQL thread

     The slave creates an SQL thread to read the relay log that is
     written by the slave I/O thread and execute the events contained
     therein.

In the preceding description, there are three threads per master/slave
connection. A master that has multiple slaves creates one binlog dump
thread for each currently connected slave, and each slave has its own
I/O and SQL threads.

A slave uses two threads to separate reading updates from the master
and executing them into independent tasks. Thus, the task of reading
statements is not slowed down if statement execution is slow. For
example, if the slave server has not been running for a while, its I/O
thread can quickly fetch all the binary log contents from the master
when the slave starts, even if the SQL thread lags far behind. If the
slave stops before the SQL thread has executed all the fetched
statements, the I/O thread has at least fetched everything so that a
safe copy of the statements is stored locally in the slave's relay
logs, ready for execution the next time that the slave starts. This
enables the master server to purge its binary logs sooner because it no
longer needs to wait for the slave to fetch their contents.

The *Note `SHOW PROCESSLIST': show-processlist. statement provides
information that tells you what is happening on the master and on the
slave regarding replication. For information on master states, see
*Note master-thread-states::. For slave states, see *Note
slave-io-thread-states::, and *Note slave-sql-thread-states::.

The following example illustrates how the three threads show up in the
output from *Note `SHOW PROCESSLIST': show-processlist.

On the master server, the output from *Note `SHOW PROCESSLIST':
show-processlist. looks like this:

     mysql> SHOW PROCESSLIST\G
     *************************** 1. row ***************************
          Id: 2
        User: root
        Host: localhost:32931
          db: NULL
     Command: Binlog Dump
        Time: 94
       State: Has sent all binlog to slave; waiting for binlog to
              be updated
        Info: NULL

Here, thread 2 is a `Binlog Dump' replication thread that services a
connected slave. The `State' information indicates that all outstanding
updates have been sent to the slave and that the master is waiting for
more updates to occur. If you see no `Binlog Dump' threads on a master
server, this means that replication is not running; that is, no slaves
are currently connected.

On a slave server, the output from *Note `SHOW PROCESSLIST':
show-processlist. looks like this:

     mysql> SHOW PROCESSLIST\G
     *************************** 1. row ***************************
          Id: 10
        User: system user
        Host:
          db: NULL
     Command: Connect
        Time: 11
       State: Waiting for master to send event
        Info: NULL
     *************************** 2. row ***************************
          Id: 11
        User: system user
        Host:
          db: NULL
     Command: Connect
        Time: 11
       State: Has read all relay log; waiting for the slave I/O
              thread to update it
        Info: NULL

The `State' information indicates that thread 10 is the I/O thread that
is communicating with the master server, and thread 11 is the SQL
thread that is processing the updates stored in the relay logs. At the
time that *Note `SHOW PROCESSLIST': show-processlist. was run, both
threads were idle, waiting for further updates.

The value in the `Time' column can show how late the slave is compared
to the master. See *Note replication-faq::. If sufficient time elapses
on the master side without activity on the `Binlog Dump' thread, the
master determines that the slave is no longer connected. As for any
other client connection, the timeouts for this depend on the values of
`net_write_timeout' and `net_retry_count'; for more information about
these, see *Note server-system-variables::.

The *Note `SHOW SLAVE STATUS': show-slave-status. statement provides
additional information about replication processing on a slave server.
See *Note replication-administration-status::.


File: manual.info,  Node: slave-logs,  Next: replication-rules,  Prev: replication-implementation-details,  Up: replication-implementation

16.2.2 Replication Relay and Status Logs
----------------------------------------

* Menu:

* slave-logs-relaylog::          The Slave Relay Log
* slave-logs-status::            Slave Status Logs

During replication, a slave server creates several logs that hold the
binary log events relayed from the master to the slave, and to record
information about the current status and location within the relay log.
There are three types of logs used in the process, listed here:

   * The _relay log_ consists of the events read from the binary log of
     the master and written by the slave I/O thread. Events in the
     relay log are executed on the slave as part of the SQL thread.

   * The _master info log_ contains status and current configuration
     information for the slave's connection to the master. This log
     holds information on the master host name, login credentials, and
     coordinates indicating how far the slave has read from the
     master's binary log.

   * The _relay log info log_ holds status information about the
     execution point within the slave's relay log.


File: manual.info,  Node: slave-logs-relaylog,  Next: slave-logs-status,  Prev: slave-logs,  Up: slave-logs

16.2.2.1 The Slave Relay Log
............................

The relay log, like the binary log, consists of a set of numbered files
containing events that describe database changes, and an index file
that contains the names of all used relay log files.

The term `relay log file' generally denotes an individual numbered file
containing database events. The term `relay log' collectively denotes
the set of numbered relay log files plus the index file.

Relay log files have the same format as binary log files and can be
read using *Note `mysqlbinlog': mysqlbinlog. (see *Note mysqlbinlog::).

By default, relay log file names have the form
`HOST_NAME-relay-bin.NNNNNN' in the data directory, where HOST_NAME is
the name of the slave server host and NNNNNN is a sequence number.
Successive relay log files are created using successive sequence
numbers, beginning with `000001'. The slave uses an index file to track
the relay log files currently in use. The default relay log index file
name is `HOST_NAME-relay-bin.index' in the data directory.

The default relay log file and relay log index file names can be
overridden with, respectively, the `--relay-log' and
`--relay-log-index' server options (see *Note replication-options::).

If a slave uses the default host-based relay log file names, changing a
slave's host name after replication has been set up can cause
replication to fail with the errors `Failed to open the relay log' and
`Could not find target log during relay log initialization'. This is a
known issue (see Bug #2122). If you anticipate that a slave's host name
might change in the future (for example, if networking is set up on the
slave such that its host name can be modified using DHCP), you can
avoid this issue entirely by using the `--relay-log' and
`--relay-log-index' options to specify relay log file names explicitly
when you initially set up the slave. This will make the names
independent of server host name changes.

If you encounter the issue after replication has already begun, one way
to work around it is to stop the slave server, prepend the contents of
the old relay log index file to the new one, and then restart the
slave. On a Unix system, this can be done as shown here:

     shell> cat NEW_RELAY_LOG_NAME.index >> OLD_RELAY_LOG_NAME.index
     shell> mv OLD_RELAY_LOG_NAME.index NEW_RELAY_LOG_NAME.index

A slave server creates a new relay log file under the following
conditions:

   * Each time the I/O thread starts.

   * When the logs are flushed; for example, with *Note `FLUSH LOGS':
     flush.  or *Note `mysqladmin flush-logs': mysqladmin.

   * When the size of the current relay log file becomes `too large,'
     determined as follows:

        * If the value of `max_relay_log_size' is greater than 0, that
          is the maximum relay log file size.

        * If the value of `max_relay_log_size' is 0, `max_binlog_size'
          determines the maximum relay log file size.

The SQL thread automatically deletes each relay log file as soon as it
has executed all events in the file and no longer needs it. There is no
explicit mechanism for deleting relay logs because the SQL thread takes
care of doing so. However, *Note `FLUSH LOGS': flush.  rotates relay
logs, which influences when the SQL thread deletes them.


File: manual.info,  Node: slave-logs-status,  Prev: slave-logs-relaylog,  Up: slave-logs

16.2.2.2 Slave Status Logs
..........................

A replication slave server creates two logs. By default, these logs are
files named `master.info' and `relay-log.info' and created in the data
directory. The names and locations of these files can be changed by
using the `--master-info-file' and `--relay-log-info-file' options,
respectively. See *Note replication-options::.

The two status logs contain information like that shown in the output
of the *Note `SHOW SLAVE STATUS': show-slave-status.  statement, which
is discussed in *Note replication-slave-sql::. Because the status logs
are stored on disk, they survive a slave server's shutdown.  The next
time the slave starts up, it reads the two logs to determine how far it
has proceeded in reading binary logs from the master and in processing
its own relay logs.

The master info log should be protected because it contains the
password for connecting to the master. See *Note
password-security-admin::.

The slave I/O thread updates the master info log. The following table
shows the correspondence between the lines in the `master.info' file
and the columns displayed by *Note `SHOW SLAVE STATUS':
show-slave-status.

Line in     `SHOW SLAVE STATUS'       Description
`master.info'Column                    
1                                     Number of lines in the file
2           `Master_Log_File'         The name of the master binary log
                                      currently being read from the master
3           `Read_Master_Log_Pos'     The current position within the
                                      master binary log that have been
                                      read from the master
4           `Master_Host'             The host name of the master
5           `Master_User'             The user name used to connect to
                                      the master
6           Password (not shown by    The password used to connect to the
            *Note `SHOW SLAVE         master
            STATUS':                  
            show-slave-status.)       
7           `Master_Port'             The network port used to connect to
                                      the master
8           `Connect_Retry'           The period (in seconds) that the
                                      slave will wait before trying to
                                      reconnect to the master
9           `Master_SSL_Allowed'      Indicates whether the server
                                      supports SSL connections
10          `Master_SSL_CA_File'      The file used for the Certificate
                                      Authority (CA) certificate
11          `Master_SSL_CA_Path'      The path to the Certificate
                                      Authority (CA) certificates
12          `Master_SSL_Cert'         The name of the SSL certificate file
13          `Master_SSL_Cipher'       The list of possible ciphers used
                                      in the handshake for the SSL
                                      connection
14          `Master_SSL_Key'          The name of the SSL key file

The slave SQL thread updates the relay log info log. The following
table shows the correspondence between the lines in the
`relay-log.info' file and the columns displayed by *Note `SHOW SLAVE
STATUS': show-slave-status.

Line in     `SHOW SLAVE STATUS'       Description
`relay-log.info'Column                    
1           `Relay_Log_File'          The name of the current relay log
                                      file
2           `Relay_Log_Pos'           The current position within the
                                      relay log file; events up to this
                                      position have been executed on the
                                      slave database
3           `Relay_Master_Log_File'   The name of the master binary log
                                      file from which the events in the
                                      relay log file were read
4           `Exec_Master_Log_Pos'     The equivalent position within the
                                      master's binary log file of events
                                      that have already been executed

The contents of the `relay-log.info' file and the states shown by the
*Note `SHOW SLAVE STATUS': show-slave-status. statement might not match
if the `relay-log.info' file has not been flushed to disk. Ideally, you
should only view `relay-log.info' on a slave that is offline (that is,
`mysqld' is not running). For a running system, *Note `SHOW SLAVE
STATUS': show-slave-status.  should be used.

When you back up the slave's data, you should back up these two status
logs, along with the relay log files. The status logs are needed to
resume replication after you restore the data from the slave. If you
lose the relay logs but still have the relay log info log, you can
check it to determine how far the SQL thread has executed in the master
binary logs. Then you can use *Note `CHANGE MASTER TO':
change-master-to. with the `MASTER_LOG_FILE' and `MASTER_LOG_POS'
options to tell the slave to re-read the binary logs from that point.
Of course, this requires that the binary logs still exist on the master.


File: manual.info,  Node: replication-rules,  Prev: slave-logs,  Up: replication-implementation

16.2.3 How Servers Evaluate Replication Filtering Rules
-------------------------------------------------------

* Menu:

* replication-rules-db-options::  Evaluation of Database-Level Replication and Binary Logging Options
* replication-rules-table-options::  Evaluation of Table-Level Replication Options
* replication-rules-examples::   Replication Rule Application

If a master server does not write a statement to its binary log, the
statement is not replicated. If the server does log the statement, the
statement is sent to all slaves and each slave determines whether to
execute it or ignore it.

On the master, you can control which databases to log changes for by
using the `--binlog-do-db' and `--binlog-ignore-db' options to control
binary logging. For a description of the rules that servers use in
evaluating these options, see *Note replication-rules-db-options::. You
should not use these options to control which databases and tables are
replicated. Instead, use filtering on the slave to control the events
that are executed on the slave.

On the slave side, decisions about whether to execute or ignore
statements received from the master are made according to the
`--replicate-*' options that the slave was started with. (See *Note
replication-options::.)

In the simplest case, when there are no `--replicate-*' options, the
slave executes all statements that it receives from the master.
Otherwise, the result depends on the particular options given.

Database-level options (`--replicate-do-db', `--replicate-ignore-db')
are checked first; see *Note replication-rules-db-options::, for a
description of this process. If no matching database-level options are
found, option checking proceeds to any table-level options that may be
in use, as discussed in *Note replication-rules-table-options::.

To make it easier to determine what effect an option set will have, it
is recommended that you avoid mixing `do' and `ignore' options, or
wildcard and nonwildcard options. An example of the latter that may
have unintended effects is the use of `--replicate-do-db' and
`--replicate-wild-do-table' together, where `--replicate-wild-do-table'
uses a pattern for the database name that matches the name given for
`--replicate-do-db'. Suppose a replication slave is started with
`--replicate-do-db=dbx' `--replicate-wild-do-table=db%.t1'.  Then,
suppose that on the master, you issue the statement *Note `CREATE
DATABASE dbx': create-database. Although you might expect it, this
statement is not replicated because it does not reference a table named
`t1'.

If any `--replicate-rewrite-db' options were specified, they are
applied before the `--replicate-*' filtering rules are tested.

*Note*:

In MySQL 5.0, database-level filtering options are case-sensitive on
platforms supporting case sensitivity in filenames, whereas table-level
filtering options are not (regardless of platform). This is true
regardless of the value of the `lower_case_table_names' system variable.


File: manual.info,  Node: replication-rules-db-options,  Next: replication-rules-table-options,  Prev: replication-rules,  Up: replication-rules

16.2.3.1 Evaluation of Database-Level Replication and Binary Logging Options
............................................................................

When evaluating replication options, the slave begins by checking to
see whether there are any `--replicate-do-db' or
`--replicate-ignore-db' options that apply. When using `--binlog-do-db'
or `--binlog-ignore-db', the process is similar, but the options are
checked on the master.

Checking of the database-level options proceeds as shown in the
following diagram.

Evaluation of Database-Level Filtering Rules in Replication

The steps involved are listed here:

  1. Are there any `--replicate-do-db' options?

        * Yes

          Do any of them match the database?

             * Yes

               Execute the statement and exit.

             * No

               Continue to step 2.

        * No

          Continue to step 2.

  2. Are there any `--replicate-ignore-db' options?

        * Yes

          Do any of them match the database?

             * Yes

               Ignore the statement and exit.

             * No

               Continue to step 3.

        * No

          Continue to step 3.

  3. Proceed to checking the table-level replication options, if there
     are any. For a description of how these options are checked, see
     *Note replication-rules-table-options::.

     *Important*:

     A statement that is still permitted at this stage is not yet
     actually executed. The statement is not executed until all
     table-level options (if any) have also been checked, and the
     outcome of that process permits execution of the statement.

For binary logging, the steps involved are listed here:

  1. Are there any `--binlog-do-db' or `--binlog-ignore-db' options?

        * Yes

          Continue to step 2.

        * No

          Log the statement and exit.

  2. Is there a default database (has any database been selected by
     *Note `USE': use.)?

        * Yes

          Continue to step 3.

        * No

          Ignore the statement and exit.

  3. There is a default database. Are there any `--binlog-do-db'
     options?

        * Yes

          Do any of them match the database?

             * Yes

               Log the statement and exit.

             * No

               Ignore the statement and exit.

        * No

          Continue to step 4.

  4. Do any of the `--binlog-ignore-db' options match the database?

        * Yes

          Ignore the statement and exit.

        * No

          Log the statement and exit.

*Important*:

An exception is made in the rules just given for the *Note `CREATE
DATABASE': create-database, *Note `ALTER DATABASE': alter-database, and
*Note `DROP DATABASE': drop-database. statements. In those cases, the
database being _created, altered, or dropped_ replaces the default
database when determining whether to log or to ignore updates.

`--binlog-do-db' can sometimes mean `ignore other databases'. For
example, a server running with only `--binlog-do-db=sales' does not
write to the binary log statements for which the default database
differs from `sales'.

Relay log files have the same format as binary log files and can be
read using *Note `mysqlbinlog': mysqlbinlog.


File: manual.info,  Node: replication-rules-table-options,  Next: replication-rules-examples,  Prev: replication-rules-db-options,  Up: replication-rules

16.2.3.2 Evaluation of Table-Level Replication Options
......................................................

The slave checks for and evaluates table options only if no matching
database options were found (see *Note replication-rules-db-options::).

First, as a preliminary condition, the slave checks whether the
statement occurs within a stored function, in which case the slave
executes the statement and exits.

Having reached this point, if there are no table options, the slave
simply executes all statements. If there are any `--replicate-do-table'
or `--replicate-wild-do-table' options, the statement must match one of
these if it is to be executed; otherwise, it is ignored. If there are
any `--replicate-ignore-table' or `--replicate-wild-ignore-table'
options, all statements are executed except those that match any of
these options. This process is illustrated in the following diagram.

Evaluation of Table-Level Filtering Rules in Replication

The `master.info' file should be protected because it contains the
password for connecting to the master.  See *Note
password-security-admin::.

The following steps describe this evaluation in more detail:

  1. Are there any table options?

        * Yes

          Continue to step 2.

        * No

          Execute the statement and exit.

  2. Are there any `--replicate-do-table' options?

        * Yes

          Does the table match any of them?

             * Yes

               Execute the statement and exit.

             * No

               Continue to step 3.

        * No

          Continue to step 3.

  3. Are there any `--replicate-ignore-table' options?

        * Yes

          Does the table match any of them?

             * Yes

               Ignore the statement and exit.

             * No

               Continue to step 4.

        * No

          Continue to step 4.

  4. Are there any `--replicate-wild-do-table' options?

        * Yes

          Does the table match any of them?

             * Yes

               Execute the statement and exit.

             * No

               Continue to step 5.

        * No

          Continue to step 5.

  5. Are there any `--replicate-wild-ignore-table' options?

        * Yes

          Does the table match any of them?

             * Yes

               Ignore the statement and exit.

             * No

               Continue to step 6.

        * No

          Continue to step 6.

  6. Are there any `--replicate-do-table' or `--replicate-wild-do-table'
     options?

        * Yes

          Ignore the statement and exit.

        * No

          Execute the statement and exit.


File: manual.info,  Node: replication-rules-examples,  Prev: replication-rules-table-options,  Up: replication-rules

16.2.3.3 Replication Rule Application
.....................................

This section provides additional explanation and examples of usage for
different combinations of replication filtering options.

Some typical combinations of replication filter rule types are given in
the following table:

Condition (Types of Options)  Outcome
No `--replicate-*' options    The slave executes all events that it
at all:                       receives from the master.
`--replicate-*-db' options,   The slave accepts or ignores statements
but no table options:         using the database options. It executes
                              all statements permitted by those options
                              because there are no table restrictions.
`--replicate-*-table'         All statements are accepted at the
options, but no database      database-checking stage because there are
options:                      no database conditions. The slave executes
                              or ignores statements based solely on the
                              table options.
A combination of database     The slave accepts or ignores statements
and table options:            using the database options. Then it
                              evaluates all statements permitted by
                              those options according to the table
                              options. This can sometimes lead to
                              results that seem counterintuitive; see
                              the text for an example.

A more complex example follows.

Suppose that we have two tables `mytbl1' in database `db1' and `mytbl2'
in database `db2' on the master, and the slave is running with the
following options (and no other replication filtering options):

     replicate-ignore-db = db1
     replicate-do-table  = db2.tbl2

Now we execute the following statements on the master:

     USE db1;
     INSERT INTO db2.tbl2 VALUES (1);

The outcome may not match initial expectations, because the `USE'
statement causes `db1' to be the default database. Thus the
`--replicate-ignore-db' option matches, which causes the *Note
`INSERT': insert.  statement to be ignored. Because there was a match
with a database-level option, the table options are not checked;
processing immediately moves to the next statement executed on the
master.


File: manual.info,  Node: replication-solutions,  Next: replication-notes,  Prev: replication-implementation,  Up: replication

16.3 Replication Solutions
==========================

* Menu:

* replication-solutions-backups::  Using Replication for Backups
* replication-solutions-diffengines::  Using Replication with Different Master and Slave Storage Engines
* replication-solutions-scaleout::  Using Replication for Scale-Out
* replication-solutions-partitioning::  Replicating Different Databases to Different Slaves
* replication-solutions-performance::  Improving Replication Performance
* replication-solutions-switch::  Switching Masters During Failover
* replication-solutions-ssl::    Setting Up Replication Using SSL

Replication can be used in many different environments for a range of
purposes. This section provides general notes and advice on using
replication for specific solution types.

For information on using replication in a backup environment, including
notes on the setup, backup procedure, and files to back up, see *Note
replication-solutions-backups::.

For advice and tips on using different storage engines on the master
and slaves, see *Note replication-solutions-diffengines::.

Using replication as a scale-out solution requires some changes in the
logic and operation of applications that use the solution. See *Note
replication-solutions-scaleout::.

For performance or data distribution reasons, you may want to replicate
different databases to different replication slaves. See *Note
replication-solutions-partitioning::

As the number of replication slaves increases, the load on the master
can increase and lead to reduced performance (because of the need to
replicate the binary log to each slave). For tips on improving your
replication performance, including using a single secondary server as
an replication master, see *Note replication-solutions-performance::.

For guidance on switching masters, or converting slaves into masters as
part of an emergency failover solution, see *Note
replication-solutions-switch::.

To secure your replication communication, you can use SSL to encrypt
the communication channel. For step-by-step instructions, see *Note
replication-solutions-ssl::.


File: manual.info,  Node: replication-solutions-backups,  Next: replication-solutions-diffengines,  Prev: replication-solutions,  Up: replication-solutions

16.3.1 Using Replication for Backups
------------------------------------

* Menu:

* replication-solutions-backups-mysqldump::  Backing Up a Slave Using `mysqldump'
* replication-solutions-backups-rawdata::  Backing Up Raw Data from a Slave

To use replication as a backup solution, replicate data from the master
to a slave, and then back up the data slave. The slave can be paused
and shut down without affecting the running operation of the master, so
you can produce an effective snapshot of `live' data that would
otherwise require the master to be shut down.

How you back up a database depends on its size and whether you are
backing up only the data, or the data and the replication slave state
so that you can rebuild the slave in the event of failure.  There are
therefore two choices:

   * If you are using replication as a solution to enable you to back
     up the data on the master, and the size of your database is not
     too large, the *Note `mysqldump': mysqldump. tool may be suitable.
     See *Note replication-solutions-backups-mysqldump::.

   * For larger databases, where *Note `mysqldump': mysqldump. would be
     impractical or inefficient, you can back up the raw data files
     instead. Using the raw data files option also means that you can
     back up the binary and relay logs that will enable you to recreate
     the slave in the event of a slave failure. For more information,
     see *Note replication-solutions-backups-rawdata::.


File: manual.info,  Node: replication-solutions-backups-mysqldump,  Next: replication-solutions-backups-rawdata,  Prev: replication-solutions-backups,  Up: replication-solutions-backups

16.3.1.1 Backing Up a Slave Using `mysqldump'
.............................................

Using *Note `mysqldump': mysqldump. to create a copy of a database
enables you to capture all of the data in the database in a format that
enables the information to be imported into another instance of MySQL
Server (see *Note mysqldump::). Because the format of the information
is SQL statements, the file can easily be distributed and applied to
running servers in the event that you need access to the data in an
emergency. However, if the size of your data set is very large, *Note
`mysqldump': mysqldump. may be impractical.

When using *Note `mysqldump': mysqldump, you should stop replication on
the slave before starting the dump process to ensure that the dump
contains a consistent set of data:

  1. Stop the slave from processing requests. You can stop replication
     completely on the slave using *Note `mysqladmin': mysqladmin.:

          shell> mysqladmin stop-slave

     Alternatively, you can stop only the slave SQL thread to pause
     event execution:

          shell> mysql -e 'STOP SLAVE SQL_THREAD;'

     This enables the slave to continue to receive data change events
     from the master's binary log and store them in the relay logs
     using the I/O thread, but prevents the slave from executing these
     events and changing its data. Within busy replication
     environments, permitting the I/O thread to run during backup may
     speed up the catch-up process when you restart the slave SQL
     thread.

  2. Run *Note `mysqldump': mysqldump. to dump your databases. You may
     either dump all databases or select databases to be dumped. For
     example, to dump all databases:

          shell> mysqldump --all-databases > fulldb.dump

  3. Once the dump has completed, start slave operations again:

          shell> mysqladmin start-slave

In the preceding example, you may want to add login credentials (user
name, password) to the commands, and bundle the process up into a
script that you can run automatically each day.

If you use this approach, make sure you monitor the slave replication
process to ensure that the time taken to run the backup does not affect
the slave's ability to keep up with events from the master. See *Note
replication-administration-status::. If the slave is unable to keep up,
you may want to add another slave and distribute the backup process.
For an example of how to configure this scenario, see *Note
replication-solutions-partitioning::.


File: manual.info,  Node: replication-solutions-backups-rawdata,  Prev: replication-solutions-backups-mysqldump,  Up: replication-solutions-backups

16.3.1.2 Backing Up Raw Data from a Slave
.........................................

To guarantee the integrity of the files that are copied, backing up the
raw data files on your MySQL replication slave should take place while
your slave server is shut down. If the MySQL server is still running,
background tasks may still be updating the database files, particularly
those involving storage engines with background processes such as
`InnoDB'.  With `InnoDB', these problems should be resolved during
crash recovery, but since the slave server can be shut down during the
backup process without affecting the execution of the master it makes
sense to take advantage of this capability.

To shut down the server and back up the files:

  1. Shut down the slave MySQL server:

          shell> mysqladmin shutdown

  2. Copy the data files. You can use any suitable copying or archive
     utility, including `cp', `tar' or `WinZip'. For example, assuming
     that the data directory is located under the current directory,
     you can archive the entire directory as follows:

          shell> tar cf /tmp/dbbackup.tar ./data

  3. Start the MySQL server again. Under Unix:

          shell> mysqld_safe &

     Under Windows:

          C:\> "C:\Program Files\MySQL\MySQL Server 5.0\bin\mysqld"

Normally you should back up the entire data directory for the slave
MySQL server. If you want to be able to restore the data and operate as
a slave (for example, in the event of failure of the slave), then in
addition to the slave's data, you should also back up the slave status
files, `master.info' and `relay-log.info', along with the relay log
files. These files are needed to resume replication after you restore
the slave's data.

If you lose the relay logs but still have the `relay-log.info' file,
you can check it to determine how far the SQL thread has executed in
the master binary logs. Then you can use *Note `CHANGE MASTER TO':
change-master-to. with the `MASTER_LOG_FILE' and `MASTER_LOG_POS'
options to tell the slave to re-read the binary logs from that point.
This requires that the binary logs still exist on the master server.

If your slave is replicating *Note `LOAD DATA INFILE': load-data.
statements, you should also back up any `SQL_LOAD-*' files that exist
in the directory that the slave uses for this purpose. The slave needs
these files to resume replication of any interrupted *Note `LOAD DATA
INFILE': load-data. operations. The location of this directory is the
value of the `--slave-load-tmpdir' option. If the server was not
started with that option, the directory location is the value of the
`tmpdir' system variable.


File: manual.info,  Node: replication-solutions-diffengines,  Next: replication-solutions-scaleout,  Prev: replication-solutions-backups,  Up: replication-solutions

16.3.2 Using Replication with Different Master and Slave Storage Engines
------------------------------------------------------------------------

It does not matter for the replication process whether the source table
on the master and the replicated table on the slave use different
engine types. In fact, the system variables `storage_engine' and
`table_type' are not replicated.

This provides a number of benefits in the replication process in that
you can take advantage of different engine types for different
replication scenarios. For example, in a typical scale-out scenario (see
*Note replication-solutions-scaleout::), you want to use `InnoDB'
tables on the master to take advantage of the transactional
functionality, but use `MyISAM' on the slaves where transaction support
is not required because the data is only read. When using replication
in a data-logging environment you may want to use the `Archive' storage
engine on the slave.

Configuring different engines on the master and slave depends on how
you set up the initial replication process:

   * If you used *Note `mysqldump': mysqldump. to create the database
     snapshot on your master, you could edit the dump file text to
     change the engine type used on each table.

     Another alternative for *Note `mysqldump': mysqldump. is to
     disable engine types that you do not want to use on the slave
     before using the dump to build the data on the slave. For example,
     you can add the `--skip-innodb' option on your slave to disable
     the `InnoDB' engine. If a specific engine does not exist for a
     table to be created, MySQL will use the default engine type,
     usually `MyISAM'. (This requires that the `NO_ENGINE_SUBSTITUTION'
     SQL mode is not enabled.) If you want to disable additional
     engines in this way, you may want to consider building a special
     binary to be used on the slave that only supports the engines you
     want.

   * If you are using raw data files (a binary backup) to set up the
     slave, you will be unable to change the initial table format.
     Instead, use *Note `ALTER TABLE': alter-table. to change the table
     types after the slave has been started.

   * For new master/slave replication setups where there are currently
     no tables on the master, avoid specifying the engine type when
     creating new tables.

If you are already running a replication solution and want to convert
your existing tables to another engine type, follow these steps:

  1. Stop the slave from running replication updates:

          mysql> STOP SLAVE;

     This will enable you to change engine types without interruptions.

  2. Execute an `ALTER TABLE ...  ENGINE='ENGINE_TYPE'' for each table
     to be changed.

  3. Start the slave replication process again:

          mysql> START SLAVE;

Although the `storage_engine' and `table_type' variables are not
replicated, be aware that *Note `CREATE TABLE': create-table. and *Note
`ALTER TABLE': alter-table.  statements that include the engine
specification will be correctly replicated to the slave. For example,
if you have a CSV table and you execute:

     mysql> ALTER TABLE csvtable Engine='MyISAM';

The above statement will be replicated to the slave and the engine type
on the slave will be converted to `MyISAM', even if you have previously
changed the table type on the slave to an engine other than CSV. If you
want to retain engine differences on the master and slave, you should
be careful to use the `storage_engine' variable on the master when
creating a new table. For example, instead of:

     mysql> CREATE TABLE tablea (columna int) Engine=MyISAM;

Use this format:

     mysql> SET storage_engine=MyISAM;
     mysql> CREATE TABLE tablea (columna int);

When replicated, the `storage_engine' variable will be ignored, and the
*Note `CREATE TABLE': create-table.  statement will execute on the
slave using the slave's default engine.


File: manual.info,  Node: replication-solutions-scaleout,  Next: replication-solutions-partitioning,  Prev: replication-solutions-diffengines,  Up: replication-solutions

16.3.3 Using Replication for Scale-Out
--------------------------------------

You can use replication as a scale-out solution; that is, where you
want to split up the load of database queries across multiple database
servers, within some reasonable limitations.

Because replication works from the distribution of one master to one or
more slaves, using replication for scale-out works best in an
environment where you have a high number of reads and low number of
writes/updates. Most Web sites fit into this category, where users are
browsing the Web site, reading articles, posts, or viewing products.
Updates only occur during session management, or when making a purchase
or adding a comment/message to a forum.

Replication in this situation enables you to distribute the reads over
the replication slaves, while still enabling your web servers to
communicate with the replication master when a write is required. You
can see a sample replication layout for this scenario in *Note
figure_replication-scaleout::.

FIGURE GOES HERE: Using Replication to Improve Performance During
Scale-Out

If the part of your code that is responsible for database access has
been properly abstracted/modularized, converting it to run with a
replicated setup should be very smooth and easy. Change the
implementation of your database access to send all writes to the
master, and to send reads to either the master or a slave. If your code
does not have this level of abstraction, setting up a replicated system
gives you the opportunity and motivation to clean it up. Start by
creating a wrapper library or module that implements the following
functions:

   * `safe_writer_connect()'

   * `safe_reader_connect()'

   * `safe_reader_statement()'

   * `safe_writer_statement()'

`safe_' in each function name means that the function takes care of
handling all error conditions. You can use different names for the
functions. The important thing is to have a unified interface for
connecting for reads, connecting for writes, doing a read, and doing a
write.

Then convert your client code to use the wrapper library. This may be a
painful and scary process at first, but it pays off in the long run.
All applications that use the approach just described are able to take
advantage of a master/slave configuration, even one involving multiple
slaves. The code is much easier to maintain, and adding troubleshooting
options is trivial. You need modify only one or two functions; for
example, to log how long each statement took, or which statement among
those issued gave you an error.

If you have written a lot of code, you may want to automate the
conversion task by using the *Note `replace': replace-utility. utility
that comes with standard MySQL distributions, or write your own
conversion script. Ideally, your code uses consistent programming style
conventions. If not, then you are probably better off rewriting it
anyway, or at least going through and manually regularizing it to use a
consistent style.


File: manual.info,  Node: replication-solutions-partitioning,  Next: replication-solutions-performance,  Prev: replication-solutions-scaleout,  Up: replication-solutions

16.3.4 Replicating Different Databases to Different Slaves
----------------------------------------------------------

There may be situations where you have a single master and want to
replicate different databases to different slaves. For example, you may
want to distribute different sales data to different departments to
help spread the load during data analysis. A sample of this layout is
shown in *Note figure_replication-multi-db::.

FIGURE GOES HERE: Using Replication to Replicate Databases to Separate
Replication Slaves

You can achieve this separation by configuring the master and slaves as
normal, and then limiting the binary log statements that each slave
processes by using the `--replicate-wild-do-table' configuration option
on each slave.

*Important*:

You should _not_ use `--replicate-do-db' for this purpose, since its
affects vary according to the database that is currently selected.

For example, to support the separation as shown in *Note
figure_replication-multi-db::, you should configure each replication
slave as follows, before executing *Note `START SLAVE': start-slave.:

   * Replication slave 1 should use
     `--replicate-wild-do-table=databaseA.%'.

   * Replication slave 2 should use
     `--replicate-wild-do-table=databaseB.%'.

   * Replication slave 3 should use
     `--replicate-wild-do-table=databaseC.%'.

Each slave in this configuration receives the entire binary log from
the master, but executes only those events from the binary log that
apply to the databases and tables included by the
`--replicate-wild-do-table' option in effect on that slave.

If you have data that must be synchronized to the slaves before
replication starts, you have a number of choices:

   * Synchronize all the data to each slave, and delete the databases,
     tables, or both that you do not want to keep.

   * Use *Note `mysqldump': mysqldump. to create a separate dump file
     for each database and load the appropriate dump file on each slave.

   * Use a raw data file dump and include only the specific files and
     databases that you need for each slave.

     *Note*:

     This does not work with *Note `InnoDB': innodb-storage-engine.
     databases unless you use `innodb_file_per_table'.


File: manual.info,  Node: replication-solutions-performance,  Next: replication-solutions-switch,  Prev: replication-solutions-partitioning,  Up: replication-solutions

16.3.5 Improving Replication Performance
----------------------------------------

As the number of slaves connecting to a master increases, the load,
although minimal, also increases, as each slave uses a client
connection to the master. Also, as each slave must receive a full copy
of the master binary log, the network load on the master may also
increase and create a bottleneck.

If you are using a large number of slaves connected to one master, and
that master is also busy processing requests (for example, as part of a
scale-out solution), then you may want to improve the performance of
the replication process.

One way to improve the performance of the replication process is to
create a deeper replication structure that enables the master to
replicate to only one slave, and for the remaining slaves to connect to
this primary slave for their individual replication requirements. A
sample of this structure is shown in *Note
figure_replication-performance::.

FIGURE GOES HERE: Using an Additional Replication Host to Improve
Performance

For this to work, you must configure the MySQL instances as follows:

   * Master 1 is the primary master where all changes and updates are
     written to the database. Binary logging should be enabled on this
     machine.

   * Master 2 is the slave to the Master 1 that provides the
     replication functionality to the remainder of the slaves in the
     replication structure. Master 2 is the only machine permitted to
     connect to Master 1. Master 2 also has binary logging enabled, and
     the `--log-slave-updates' option so that replication instructions
     from Master 1 are also written to Master 2's binary log so that
     they can then be replicated to the true slaves.

   * Slave 1, Slave 2, and Slave 3 act as slaves to Master 2, and
     replicate the information from Master 2, which actually consists
     of the upgrades logged on Master 1.

The above solution reduces the client load and the network interface
load on the primary master, which should improve the overall
performance of the primary master when used as a direct database
solution.

If your slaves are having trouble keeping up with the replication
process on the master, there are a number of options available:

   * If possible, put the relay logs and the data files on different
     physical drives. To do this, use the `--relay-log' option to
     specify the location of the relay log.

   * If the slaves are significantly slower than the master, you may
     want to divide up the responsibility for replicating different
     databases to different slaves. See *Note
     replication-solutions-partitioning::.

   * If your master makes use of transactions and you are not concerned
     about transaction support on your slaves, use `MyISAM' or another
     nontransactional engine on the slaves. See *Note
     replication-solutions-diffengines::.

   * If your slaves are not acting as masters, and you have a potential
     solution in place to ensure that you can bring up a master in the
     event of failure, then you can switch off `--log-slave-updates'.
     This prevents `dumb' slaves from also logging events they have
     executed into their own binary log.


File: manual.info,  Node: replication-solutions-switch,  Next: replication-solutions-ssl,  Prev: replication-solutions-performance,  Up: replication-solutions

16.3.6 Switching Masters During Failover
----------------------------------------

There is currently no official solution for providing failover between
master and slaves in the event of a failure. With the currently
available features, you would have to set up a master and a slave (or
several slaves), and to write a script that monitors the master to
check whether it is up. Then instruct your applications and the slaves
to change master in case of failure.

Remember that you can tell a slave to change its master at any time,
using the *Note `CHANGE MASTER TO': change-master-to.  statement. The
slave will not check whether the databases on the master are compatible
with the slave, it will just start reading and executing events from
the specified binary log coordinates on the new master. In a failover
situation, all the servers in the group are typically executing the
same events from the same binary log file, so changing the source of
the events should not affect the database structure or integrity
providing you are careful.

Run your slaves with the `--log-bin' option and without
`--log-slave-updates'. In this way, the slave is ready to become a
master as soon as you issue *Note `STOP SLAVE': stop-slave.; *Note
`RESET MASTER': reset-master, and *Note `CHANGE MASTER TO':
change-master-to. statement on the other slaves. For example, assume
that you have the structure shown in *Note
figure_replication-redundancy-before::.

FIGURE GOES HERE: Redundancy Using Replication, Initial Structure

In this diagram, the `MySQL Master' holds the master database, the
`MySQL Slave' hosts are replication slaves, and the `Web Client'
machines are issuing database reads and writes. Web clients that issue
only reads (and would normally be connected to the slaves) are not
shown, as they do not need to switch to a new server in the event of
failure. For a more detailed example of a read/write scale-out
replication structure, see *Note replication-solutions-scaleout::.

Each MySQL Slave (`Slave 1', `Slave 2', and `Slave 3') is a slave
running with `--log-bin' and without `--log-slave-updates'. Because
updates received by a slave from the master are not logged in the
binary log unless `--log-slave-updates' is specified, the binary log on
each slave is empty initially. If for some reason `MySQL Master'
becomes unavailable, you can pick one of the slaves to become the new
master. For example, if you pick `Slave 1', all `Web Clients' should be
redirected to `Slave 1', which will log updates to its binary log.
`Slave 2' and `Slave 3' should then replicate from `Slave 1'.

The reason for running the slave without `--log-slave-updates' is to
prevent slaves from receiving updates twice in case you cause one of the
slaves to become the new master. Suppose that `Slave 1' has
`--log-slave-updates' enabled. Then it will write updates that it
receives from `Master' to its own binary log. When `Slave 2' changes
from `Master' to `Slave 1' as its master, it may receive updates from
`Slave 1' that it has already received from `Master'

Make sure that all slaves have processed any statements in their relay
log. On each slave, issue `STOP SLAVE IO_THREAD', then check the output
of *Note `SHOW PROCESSLIST': show-processlist. until you see `Has read
all relay log'. When this is true for all slaves, they can be
reconfigured to the new setup. On the slave `Slave 1' being promoted to
become the master, issue *Note `STOP SLAVE': stop-slave. and *Note
`RESET MASTER': reset-master.

On the other slaves `Slave 2' and `Slave 3', use *Note `STOP SLAVE':
stop-slave. and `CHANGE MASTER TO MASTER_HOST='Slave1'' (where
`'Slave1'' represents the real host name of `Slave 1'). To use *Note
`CHANGE MASTER TO': change-master-to, add all information about how to
connect to `Slave 1' from `Slave 2' or `Slave 3' (USER, PASSWORD,
PORT). In *Note `CHANGE MASTER TO': change-master-to, there is no need
to specify the name of the `Slave 1' binary log file or log position to
read from: We know it is the first binary log file and position 4,
which are the defaults for *Note `CHANGE MASTER TO': change-master-to.
Finally, use *Note `START SLAVE': start-slave. on `Slave 2' and `Slave
3'.

Once the new replication is in place, you will then need to instruct
each `Web Client' to direct its statements to `Slave 1'. From that
point on, all updates statements sent by `Web Client' to `Slave 1' are
written to the binary log of `Slave 1', which then contains every update
statement sent to `Slave 1' since `Master' died.

The resulting server structure is shown in *Note
figure_replication-redundancy-after::.

FIGURE GOES HERE: Redundancy Using Replication, After Master Failure

When `Master' is up again, you must issue on it the same *Note `CHANGE
MASTER TO': change-master-to. as that issued on `Slave 2' and `Slave
3', so that `Master' becomes a slave of `S1' and picks up each `Web
Client' writes that it missed while it was down.

To make `Master' a master again (for example, because it is the most
powerful machine), use the preceding procedure as if `Slave 1' was
unavailable and `Master' was to be the new master. During this
procedure, do not forget to run *Note `RESET MASTER': reset-master. on
`Master' before making `Slave 1', `Slave 2', and `Slave 3' slaves of
`Master'.  Otherwise, they may pick up old `Web Client' writes from
before the point at which `Master' became unavailable.

Note that there is no synchronization between the different slaves to a
master. Some slaves might be ahead of others. This means that the
concept outlined in the previous example might not work. In practice,
however, the relay logs of different slaves will most likely not be far
behind the master, so it would work, anyway (but there is no guarantee).

A good way to keep your applications informed as to the location of the
master is by having a dynamic DNS entry for the master.  With `bind'
you can use `nsupdate' to dynamically update your DNS.


File: manual.info,  Node: replication-solutions-ssl,  Prev: replication-solutions-switch,  Up: replication-solutions

16.3.7 Setting Up Replication Using SSL
---------------------------------------

To use SSL for encrypting the transfer of the binary log required
during replication, both the master and the slave must support SSL
network connections. If either host does not support SSL connections
(because it has not been compiled or configured for SSL), replication
through an SSL connection is not possible.

Setting up replication using an SSL connection is similar to setting up
a server and client using SSL. You must obtain (or create) a suitable
security certificate that you can use on the master, and a similar
certificate (from the same certificate authority) on each slave.

For more information on setting up a server and client for SSL
connectivity, see *Note secure-using-ssl::.

To enable SSL on the master you must create or obtain suitable
certificates, and then add the following configuration options to the
master's configuration within the `[mysqld]' section of the master's
`my.cnf' file:

     [mysqld]
     ssl-ca=CACERT.PEM
     ssl-cert=SERVER-CERT.PEM
     ssl-key=SERVER-KEY.PEM

The paths to the certificates may be relative or absolute; we recommend
that you always use complete paths for this purpose.

The options are as follows:

   * `ssl-ca' identifies the Certificate Authority (CA) certificate.

   * `ssl-cert' identifies the server public key.  This can be sent to
     the client and authenticated against the CA certificate that it
     has.

   * `ssl-key' identifies the server private key.

On the slave, you have two options available for setting the SSL
information. You can either add the slave certificates to the
`[client]' section of the slave's `my.cnf' file, or you can explicitly
specify the SSL information using the *Note `CHANGE MASTER TO':
change-master-to. statement:

   * To add the slave certificates using an option file, add the
     following lines to the `[client]' section of the slave's `my.cnf'
     file:

          [client]
          ssl-ca=CACERT.PEM
          ssl-cert=CLIENT-CERT.PEM
          ssl-key=CLIENT-KEY.PEM

     Restart the slave server, using the `--skip-slave-start' option to
     prevent the slave from connecting to the master. Use *Note `CHANGE
     MASTER TO': change-master-to. to specify the master configuration,
     using the `MASTER_SSL' option to enable SSL connectivity:

          mysql> CHANGE MASTER TO
              -> MASTER_HOST='master_hostname',
              -> MASTER_USER='replicate',
              -> MASTER_PASSWORD='password',
              -> MASTER_SSL=1;

   * To specify the SSL certificate options using the *Note `CHANGE
     MASTER TO': change-master-to. statement, append the SSL options:

          mysql> CHANGE MASTER TO
              -> MASTER_HOST='master_hostname',
              -> MASTER_USER='replicate',
              -> MASTER_PASSWORD='password',
              -> MASTER_SSL=1,
              -> MASTER_SSL_CA = 'ca_file_name',
              -> MASTER_SSL_CAPATH = 'ca_directory_name',
              -> MASTER_SSL_CERT = 'cert_file_name',
              -> MASTER_SSL_KEY = 'key_file_name';

After the master information has been updated, start the slave
replication process:

     mysql> START SLAVE;

You can use the *Note `SHOW SLAVE STATUS': show-slave-status.
statement to confirm that the SSL connection was established
successfully.

For more information on the *Note `CHANGE MASTER TO': change-master-to.
statement, see *Note change-master-to::.

If you want to enforce the use of SSL connections during replication,
then create a user with the `REPLICATION SLAVE' privilege and use the
`REQUIRE SSL' option for that user. For example:

     mysql> CREATE USER 'repl'@'%.mydomain.com' IDENTIFIED BY 'slavepass';
     mysql> GRANT REPLICATION SLAVE ON *.*
         -> TO 'repl'@'%.mydomain.com' REQUIRE SSL;

If the account already exists, you can add `REQUIRE SSL' to it with
this statement:

     mysql> GRANT USAGE ON *.*
         -> TO 'repl'@'%.mydomain.com' REQUIRE SSL;


File: manual.info,  Node: replication-notes,  Prev: replication-solutions,  Up: replication

16.4 Replication Notes and Tips
===============================

* Menu:

* replication-features::         Replication Features and Issues
* replication-compatibility::    Replication Compatibility Between MySQL Versions
* replication-upgrade::          Upgrading a Replication Setup
* replication-faq::              Replication FAQ
* replication-problems::         Troubleshooting Replication
* replication-bugs::             How to Report Replication Bugs or Problems


File: manual.info,  Node: replication-features,  Next: replication-compatibility,  Prev: replication-notes,  Up: replication-notes

16.4.1 Replication Features and Issues
--------------------------------------

* Menu:

* replication-features-auto-increment::  Replication and `AUTO_INCREMENT'
* replication-features-charset::  Replication and Character Sets
* replication-features-create-select::  Replication of `CREATE TABLE ... SELECT' Statements
* replication-features-drop-if-exists::  Replication of `DROP ... IF EXISTS' Statements
* replication-features-directory::  Replication and `DIRECTORY' Table Options
* replication-features-floatvalues::  Replication and Floating-Point Values
* replication-features-flush::   Replication and `FLUSH'
* replication-features-functions::  Replication and System Functions
* replication-features-limit::   Replication and `LIMIT'
* replication-features-load::    Replication and `LOAD' Operations
* replication-features-logging::  Replication and the Slow Query Log
* replication-features-repair-table::  Replication and `REPAIR TABLE'
* replication-features-shutdowns::  Replication and Master or Slave Shutdowns
* replication-features-memory::  Replication and `MEMORY' Tables
* replication-features-temptables::  Replication and Temporary Tables
* replication-features-mysqldb::  Replication of the `mysql' System Database
* replication-features-userprivs::  Replication and User Privileges
* replication-features-optimizer::  Replication and the Query Optimizer
* replication-features-reserved-words::  Replication and Reserved Words
* replication-features-slaveerrors::  Slave Errors During Replication
* replication-features-sql-mode::  Replication and Server SQL Mode
* replication-features-timeout::  Replication Retries and Timeouts
* replication-features-timestamp::  Replication and `TIMESTAMP'
* replication-features-timezone::  Replication and Time Zones
* replication-features-transactions::  Replication and Transactions
* replication-features-triggers::  Replication and Triggers
* replication-features-views::   Replication and Views
* replication-features-variables::  Replication and Variables

The following sections provide information about what is supported and
what is not in MySQL replication, and about specific issues and
situations that may occur when replicating certain statements.

Statement-based replication depends on compatibility at the SQL level
between the master and slave. In others, successful SBR requires that
any SQL features used be supported by both the master and the slave
servers. For example, if you use a feature on the master server that is
available only in MySQL 5.0 (or later), you cannot replicate to a slave
that uses MySQL 4.1 (or earlier).

Such incompatibilities also can occur within a release series when
using pre-production releases of MySQL. For example, the `SLEEP()'
function is available beginning with MySQL 5.0.12. If you use this
function on the master, you cannot replicate to a slave that uses MySQL
5.0.11 or earlier.

For this reason, use Generally Available (GA) releases of MySQL for
statement-based replication in a production setting, since we do not
introduce new SQL statements or change their behavior within a given
release series once that series reaches GA release status.

If you are planning to use replication between MySQL 5.0 and a previous
MySQL release series, it is also a good idea to consult the edition of
the `MySQL Reference Manual' corresponding to the earlier release
series for information regarding the replication characteristics of that
series.

For additional information specific to replication and `InnoDB', see
*Note innodb-and-mysql-replication::.


File: manual.info,  Node: replication-features-auto-increment,  Next: replication-features-charset,  Prev: replication-features,  Up: replication-features

16.4.1.1 Replication and `AUTO_INCREMENT'
.........................................

Replication of `AUTO_INCREMENT', `LAST_INSERT_ID()', and *Note
`TIMESTAMP': datetime. values is done correctly, subject to the
following exceptions.

   * `INSERT DELAYED ...  VALUES(LAST_INSERT_ID())' inserts a different
     value on the master and the slave. (Bug #20819) This is fixed in
     MySQL 5.1 when using row-based or mixed-format binary logging. For
     more information, see Replication Formats
     (http://dev.mysql.com/doc/refman/5.1/en/replication-formats.html).

   * Before MySQL 5.0.26, a stored procedure that uses
     `LAST_INSERT_ID()' does not replicate properly.

   * When a statement uses a stored function that inserts into an
     `AUTO_INCREMENT' column, the generated `AUTO_INCREMENT' value is
     not written into the binary log, so a different value can in some
     cases be inserted on the slave. This is also true of a trigger that
     causes an *Note `INSERT': insert. into an `AUTO_INCREMENT' column.

   * An insert into an `AUTO_INCREMENT' column caused by a stored
     routine or trigger running on a master that uses MySQL 5.0.60 or
     earlier does not replicate correctly to a slave running MySQL
     5.1.12 through 5.1.23 (inclusive). (Bug #33029)

   * Adding an `AUTO_INCREMENT' column to a table with *Note `ALTER
     TABLE': alter-table. might not produce the same ordering of the
     rows on the slave and the master. This occurs because the order in
     which the rows are numbered depends on the specific storage engine
     used for the table and the order in which the rows were inserted.
     If it is important to have the same order on the master and slave,
     the rows must be ordered before assigning an `AUTO_INCREMENT'
     number. Assuming that you want to add an `AUTO_INCREMENT' column
     to a table `t1' that has columns `col1' and `col2', the following
     statements produce a new table `t2' identical to `t1' but with an
     `AUTO_INCREMENT' column:

          CREATE TABLE t2 LIKE t1;
          ALTER TABLE t2 ADD id INT AUTO_INCREMENT PRIMARY KEY;
          INSERT INTO t2 SELECT * FROM t1 ORDER BY col1, col2;

     *Important*:

     To guarantee the same ordering on both master and slave, the
     `ORDER BY' clause must name _all_ columns of `t1'.

     The instructions just given are subject to the limitations of
     `CREATE TABLE ... LIKE': Foreign key definitions are ignored, as
     are the `DATA DIRECTORY' and `INDEX DIRECTORY' table options. If a
     table definition includes any of those characteristics, create
     `t2' using a *Note `CREATE TABLE': create-table. statement that is
     identical to the one used to create `t1', but with the addition of
     the `AUTO_INCREMENT' column.

     Regardless of the method used to create and populate the copy
     having the `AUTO_INCREMENT' column, the final step is to drop the
     original table and then rename the copy:

          DROP t1;
          ALTER TABLE t2 RENAME t1;

     See also *Note alter-table-problems::.


File: manual.info,  Node: replication-features-charset,  Next: replication-features-create-select,  Prev: replication-features-auto-increment,  Up: replication-features

16.4.1.2 Replication and Character Sets
.......................................

The following applies to replication between MySQL servers that use
different character sets:

   * If the master uses MySQL 4.1, you must _always_ use the same
     _global_ character set and collation on the master and the slave,
     regardless of the slave MySQL version. (These are controlled by the
     `--character-set-server' and `--collation-server' options.)
     Otherwise, you may get duplicate-key errors on the slave, because
     a key that is unique in the master character set might not be
     unique in the slave character set. Note that this is not a cause
     for concern when master and slave are both MySQL 5.0 or later.

   * If the master is older than MySQL 4.1.3, the character set of any
     client should never be made different from its global value
     because this character set change is not known to the slave. In
     other words, clients should not use `SET NAMES', `SET CHARACTER
     SET', and so forth. If both the master and the slave are 4.1.3 or
     newer, clients can freely set session values for character set
     variables because these settings are written to the binary log and
     so are known to the slave. That is, clients can use `SET NAMES' or
     `SET CHARACTER SET' or can set variables such as
     `collation_client' or `collation_server'. However, clients are
     prevented from changing the _global_ value of these variables; as
     stated previously, the master and slave must always have identical
     global character set values.

   * If the master has databases with a character set different from
     the global `character_set_server' value, you should design your
     *Note `CREATE TABLE': create-table. statements so that they do not
     implicitly rely on the database default character set. A good
     workaround is to state the character set and collation explicitly
     in *Note `CREATE TABLE': create-table.  statements.


File: manual.info,  Node: replication-features-create-select,  Next: replication-features-drop-if-exists,  Prev: replication-features-charset,  Up: replication-features

16.4.1.3 Replication of `CREATE TABLE ... SELECT' Statements
............................................................

This section discusses the rules that are applied when a *Note `CREATE
TABLE ... SELECT': create-table-select. statement is replicated.

*Note*:

*Note `CREATE TABLE ... SELECT': create-table-select. always performs
an implicit commit (*Note implicit-commit::).

Statement succeeds

A successful *Note `CREATE TABLE ... SELECT': create-table. is itself
replicated.

Statement fails

A failed *Note `CREATE TABLE ... SELECT': create-table-select.
replicates as follows:

   * Statement does not use `IF NOT EXISTS'

     The statement has no effect. However, the implicit commit caused
     by the statement is logged. This is true regardless of the storage
     engine used and the reason for which the statement failed.

   * Statement uses `IF NOT EXISTS'

     The `CREATE TABLE IF NOT EXISTS ...  SELECT' is logged with an
     error.


File: manual.info,  Node: replication-features-drop-if-exists,  Next: replication-features-directory,  Prev: replication-features-create-select,  Up: replication-features

16.4.1.4 Replication of `DROP ... IF EXISTS' Statements
.......................................................

The *Note `DROP DATABASE IF EXISTS': drop-database, *Note `DROP TABLE
IF EXISTS': drop-table, and *Note `DROP VIEW IF EXISTS': drop-view.
statements are always replicated, even if the database, table, or view
to be dropped does not exist on the master. This is to ensure that the
object to be dropped no longer exists on either the master or the
slave, once the slave has caught up with the master.

Beginning with MySQL 5.0.82, `DROP ... IF EXISTS' statements for stored
programs (stored procedures and functions, triggers, and events) are
also replicated, even if the stored program to be dropped does not
exist on the master. (Bug #13684)


File: manual.info,  Node: replication-features-directory,  Next: replication-features-floatvalues,  Prev: replication-features-drop-if-exists,  Up: replication-features

16.4.1.5 Replication and `DIRECTORY' Table Options
..................................................

If a `DATA DIRECTORY' or `INDEX DIRECTORY' table option is used in a
*Note `CREATE TABLE': create-table. statement on the master server, the
table option is also used on the slave. This can cause problems if no
corresponding directory exists in the slave host file system or if it
exists but is not accessible to the slave server. This can be
overridden by using the `NO_DIR_IN_CREATE' server SQL mode on the
slave, which causes the slave to ignore the `DATA DIRECTORY' and `INDEX
DIRECTORY' table options when replicating *Note `CREATE TABLE':
create-table. statements. The result is that `MyISAM' data and index
files are created in the table's database directory.

For more information, see *Note server-sql-mode::.


File: manual.info,  Node: replication-features-floatvalues,  Next: replication-features-flush,  Prev: replication-features-directory,  Up: replication-features

16.4.1.6 Replication and Floating-Point Values
..............................................

With statement-based replication, values are converted from decimal to
binary. Because conversions between decimal and binary representations
of them may be approximate, comparisons involving floating-point values
are inexact. This is true for operations that use floating-point values
explicitly, or that use values that are converted to floating-point
implicitly.  Comparisons of floating-point values might yield different
results on master and slave servers due to differences in computer
architecture, the compiler used to build MySQL, and so forth. See *Note
type-conversion::, and *Note problems-with-float::.


File: manual.info,  Node: replication-features-flush,  Next: replication-features-functions,  Prev: replication-features-floatvalues,  Up: replication-features

16.4.1.7 Replication and `FLUSH'
................................

Some forms of the *Note `FLUSH': flush. statement are not logged
because they could cause problems if replicated to a slave: *Note
`FLUSH LOGS': flush, *Note `FLUSH MASTER': flush, *Note `FLUSH SLAVE':
flush, and *Note `FLUSH TABLES WITH READ LOCK': flush. For a syntax
example, see *Note flush::. The *Note `FLUSH TABLES': flush, *Note
`ANALYZE TABLE': analyze-table, *Note `OPTIMIZE TABLE': optimize-table,
and *Note `REPAIR TABLE': repair-table. statements are written to the
binary log and thus replicated to slaves. This is not normally a
problem because these statements do not modify table data.

However, this behavior can cause difficulties under certain
circumstances. If you replicate the privilege tables in the `mysql'
database and update those tables directly without using *Note `GRANT':
grant, you must issue a *Note `FLUSH PRIVILEGES': flush. on the slaves
to put the new privileges into effect. In addition, if you use *Note
`FLUSH TABLES': flush.  when renaming a `MyISAM' table that is part of
a `MERGE' table, you must issue *Note `FLUSH TABLES': flush.  manually
on the slaves. These statements are written to the binary log unless
you specify `NO_WRITE_TO_BINLOG' or its alias `LOCAL'.


File: manual.info,  Node: replication-features-functions,  Next: replication-features-limit,  Prev: replication-features-flush,  Up: replication-features

16.4.1.8 Replication and System Functions
.........................................

Certain functions do not replicate well under some conditions:

   * The `USER()', `CURRENT_USER()', `UUID()', `VERSION()', and
     `LOAD_FILE()' functions are replicated without change and thus do
     not work reliably on the slave.

   * For `NOW()', the binary log includes the timestamp. This means
     that the value _as returned by the call to this function on the
     master_ is replicated to the slave. This can lead to a possibly
     unexpected result when replicating between MySQL servers in
     different time zones. Suppose that the master is located in New
     York, the slave is located in Stockholm, and both servers are
     using local time. Suppose further that, on the master, you create
     a table `mytable', perform an *Note `INSERT': insert. statement on
     this table, and then select from the table, as shown here:

          mysql> CREATE TABLE mytable (mycol TEXT);
          Query OK, 0 rows affected (0.06 sec)

          mysql> INSERT INTO mytable VALUES ( NOW() );
          Query OK, 1 row affected (0.00 sec)

          mysql> SELECT * FROM mytable;
          +---------------------+
          | mycol               |
          +---------------------+
          | 2009-09-01 12:00:00 |
          +---------------------+
          1 row in set (0.00 sec)

     Local time in Stockholm is 6 hours later than in New York; so, if
     you issue `SELECT NOW()' on the slave at that exact same instant,
     the value `2009-09-01 18:00:00' is returned. For this reason, if
     you select from the slave's copy of `mytable' after the *Note
     `CREATE TABLE': create-table. and *Note `INSERT': insert.
     statements just shown have been replicated, you might expect
     `mycol' to contain the value `2009-09-01 18:00:00'. However, this
     is not the case; when you select from the slave's copy of
     `mytable', you obtain exactly the same result as on the master:

          mysql> SELECT * FROM mytable;
          +---------------------+
          | mycol               |
          +---------------------+
          | 2009-09-01 12:00:00 |
          +---------------------+
          1 row in set (0.00 sec)

     As of MySQL 5.0.13, the `SYSDATE()' function is no longer
     equivalent to `NOW()'.  Implications are that `SYSDATE()' is not
     replication-safe because it is not affected by `SET TIMESTAMP'
     statements in the binary log and is nondeterministic. To avoid
     this, you can start the server with the `--sysdate-is-now' option
     to cause `SYSDATE()' to be an alias for `NOW()'.

     See also *Note replication-features-timezone::.

   * The `GET_LOCK()', `RELEASE_LOCK()', `IS_FREE_LOCK()', and
     `IS_USED_LOCK()' functions that handle user-level locks are
     replicated without the slave knowing the concurrency context on
     the master. Therefore, these functions should not be used to
     insert into a master table because the content on the slave would
     differ. For example, do not issue a statement such as `INSERT INTO
     mytable VALUES(GET_LOCK(...))'.

As a workaround for the preceding limitations, you can use the strategy
of saving the problematic function result in a user variable and
referring to the variable in a later statement. For example, the
following single-row *Note `INSERT': insert. is problematic due to the
reference to the `UUID()' function:

     INSERT INTO t VALUES(UUID());

To work around the problem, do this instead:

     SET @my_uuid = UUID();
     INSERT INTO t VALUES(@my_uuid);

That sequence of statements replicates because the value of `@my_uuid'
is stored in the binary log as a user-variable event prior to the *Note
`INSERT': insert. statement and is available for use in the *Note
`INSERT': insert.

The same idea applies to multiple-row inserts, but is more cumbersome
to use. For a two-row insert, you can do this:

     SET @my_uuid1 = UUID(); @my_uuid2 = UUID();
     INSERT INTO t VALUES(@my_uuid1),(@my_uuid2);

However, if the number of rows is large or unknown, the workaround is
difficult or impracticable. For example, you cannot convert the
following statement to one in which a given individual user variable is
associated with each row:

     INSERT INTO t2 SELECT UUID(), * FROM t1;

Non-delayed *Note `INSERT': insert. statements that refer to `RAND()' or
user-defined variables replicate correctly. However, changing the
statements to use *Note `INSERT DELAYED': insert-delayed. can result in
different results on master and slave.

Within a stored function, `RAND()' replicates correctly as long as it
is invoked only once during the execution of the function. (You can
consider the function execution timestamp and random number seed as
implicit inputs that are identical on the master and slave.)

The `FOUND_ROWS()' and `ROW_COUNT()' functions are also not replicated
reliably. A workaround is to store the result of the function call in a
user variable, and then use that in the *Note `INSERT': insert.
statement. For example, if you wish to store the result in a table named
`mytable', you might normally do so like this:

     SELECT SQL_CALC_FOUND_ROWS FROM mytable LIMIT 1;
     INSERT INTO mytable VALUES( FOUND_ROWS() );

However, if you are replicating `mytable', you should use *Note `SELECT
... INTO': select-into, and then store the variable in the table, like
this:

     SELECT SQL_CALC_FOUND_ROWS INTO @found_rows FROM mytable LIMIT 1;
     INSERT INTO mytable VALUES(@found_rows);

In this way, the user variable is replicated as part of the context,
and applied on the slave correctly.


File: manual.info,  Node: replication-features-limit,  Next: replication-features-load,  Prev: replication-features-functions,  Up: replication-features

16.4.1.9 Replication and `LIMIT'
................................

Replication of `LIMIT' clauses in *Note `DELETE': delete, *Note
`UPDATE': update, and *Note `INSERT ... SELECT': insert-select.
statements is not guaranteed, since the order of the rows affected is
not defined. Such statements can be replicated correctly only if they
also contain an `ORDER BY' clause.


File: manual.info,  Node: replication-features-load,  Next: replication-features-logging,  Prev: replication-features-limit,  Up: replication-features

16.4.1.10 Replication and `LOAD' Operations
...........................................

Using `LOAD TABLE FROM MASTER' where the master is running MySQL 4.1
and the slave is running MySQL 5.0 may corrupt the table data, and is
not supported. (Bug #16261)

The *Note `LOAD DATA INFILE': load-data. statement `CONCURRENT' option
is not replicated; that is, `LOAD DATA CONCURRENT INFILE' is replicated
as *Note `LOAD DATA INFILE': load-data, and `LOAD DATA CONCURRENT LOCAL
INFILE' is replicated as *Note `LOAD DATA LOCAL INFILE': load-data.
(Bug #34628)

_The following applies only if either the master or the slave is
running MySQL 5.0.3 or older_: If on the master a *Note `LOAD DATA
INFILE': load-data. is interrupted (integrity constraint violation,
killed connection, and so on), the slave skips the *Note `LOAD DATA
INFILE': load-data. entirely. This means that if this command
permanently inserted or updated table records before being interrupted,
these modifications are not replicated to the slave.


File: manual.info,  Node: replication-features-logging,  Next: replication-features-repair-table,  Prev: replication-features-load,  Up: replication-features

16.4.1.11 Replication and the Slow Query Log
............................................

Replication slaves do not write replicated queries to the slow query
log, even if the same queries were written to the slow query log on the
master. This is a known issue. (Bug #23300)


File: manual.info,  Node: replication-features-repair-table,  Next: replication-features-shutdowns,  Prev: replication-features-logging,  Up: replication-features

16.4.1.12 Replication and `REPAIR TABLE'
........................................

When used on a corrupted or otherwise damaged table, it is possible for
the *Note `REPAIR TABLE': repair-table.  statement to delete rows that
cannot be recovered. However, any such modifications of table data
performed by this statement are not replicated, which can cause master
and slave to lose synchronization. For this reason, in the event that a
table on the master becomes damaged and you use *Note `REPAIR TABLE':
repair-table. to repair it, you should first stop replication (if it is
still running) before using *Note `REPAIR TABLE': repair-table, then
afterward compare the master's and slave's copies of the table and be
prepared to correct any discrepancies manually, before restarting
replication.


File: manual.info,  Node: replication-features-shutdowns,  Next: replication-features-memory,  Prev: replication-features-repair-table,  Up: replication-features

16.4.1.13 Replication and Master or Slave Shutdowns
...................................................

It is safe to shut down a master server and restart it later.  When a
slave loses its connection to the master, the slave tries to reconnect
immediately and retries periodically if that fails.  The default is to
retry every 60 seconds. This may be changed with the *Note `CHANGE
MASTER TO': change-master-to.  statement or `--master-connect-retry'
option. A slave also is able to deal with network connectivity outages.
However, the slave notices the network outage only after receiving no
data from the master for `slave_net_timeout' seconds. If your outages
are short, you may want to decrease `slave_net_timeout'. See *Note
server-system-variables::.

An unclean shutdown (for example, a crash) on the master side can
result in the master binary log having a final position less than the
most recent position read by the slave, due to the master binary log
file not being flushed. This can cause the slave not to be able to
replicate when the master comes back up.  Setting `sync_binlog=1' in the
master `my.cnf' file helps to minimize this problem because it causes
the master to flush its binary log more frequently.

Unclean master shutdowns may cause inconsistencies between the content
of tables and the binary log. This can be avoided by using `InnoDB'
tables and the `--innodb-safe-binlog' option on the master. See *Note
binary-log::.

*Note*:

`--innodb-safe-binlog' is unneeded as of MySQL 5.0.3, having been made
obsolete by the introduction of XA transaction support.

Shutting down a slave cleanly is safe because it keeps track of where
it left off. However, be careful that the slave does not have temporary
tables open; see *Note replication-features-temptables::. Unclean
shutdowns might produce problems, especially if the disk cache was not
flushed to disk before the problem occurred:

   * For transactions, the slave commits and then updates
     `relay-log.info'. If a crash occurs between these two operations,
     relay log processing will have proceeded further than the
     information file indicates and the slave will re-execute the
     events from the last transaction in the relay log after it has
     been restarted.

   * A similar problem can occur if the slave updates `relay-log.info'
     but the server host crashes before the write has been flushed to
     disk. Writes are not forced to disk because the server relies on
     the operating system to flush the file from time to time.

The fault tolerance of your system for these types of problems is
greatly increased if you have a good uninterruptible power supply.


File: manual.info,  Node: replication-features-memory,  Next: replication-features-temptables,  Prev: replication-features-shutdowns,  Up: replication-features

16.4.1.14 Replication and `MEMORY' Tables
.........................................

When a master server shuts down and restarts, its *Note `MEMORY':
memory-storage-engine.  (*Note `HEAP': memory-storage-engine.) tables
become empty. To replicate this effect to slaves, the first time that
the master uses a given *Note `MEMORY': memory-storage-engine. table
after startup, it logs an event that notifies slaves that the table
must to be emptied by writing a *Note `DELETE': delete. statement for
that table to the binary log.

When a slave server shuts down and restarts, its *Note `MEMORY':
memory-storage-engine. tables become empty. This causes the slave to be
out of synchrony with the master and may lead to other failures or
cause the slave to stop. For example, *Note `INSERT INTO ... SELECT
FROM MEMORY_TABLE': insert-select.  may insert a different set of rows
on the master and slave.

The safe way to restart a slave that is replicating *Note `MEMORY':
memory-storage-engine. tables is to first drop or delete all rows from
the *Note `MEMORY': memory-storage-engine.  tables on the master and
wait until those changes have replicated to the slave. Then it is safe
to restart the slave.

See *Note memory-storage-engine::, for more information about *Note
`MEMORY': memory-storage-engine. tables.


File: manual.info,  Node: replication-features-temptables,  Next: replication-features-mysqldb,  Prev: replication-features-memory,  Up: replication-features

16.4.1.15 Replication and Temporary Tables
..........................................

Safe slave shutdown when using temporary tables

Temporary tables are replicated except in the case where you stop the
slave server (not just the slave threads) and you have replicated
temporary tables that are open for use in updates that have not yet
been executed on the slave. If you stop the slave server, the temporary
tables needed by those updates are no longer available when the slave
is restarted.  To avoid this problem, do not shut down the slave while
it has temporary tables open. Instead, use the following procedure:

  1. Issue a `STOP SLAVE SQL_THREAD' statement.

  2. Use *Note `SHOW STATUS': show-status. to check the value of the
     `Slave_open_temp_tables' variable.

  3. If the value is not 0, restart the slave SQL thread with `START
     SLAVE SQL_THREAD' and repeat the procedure later.

  4. When the value is 0, issue a *Note `mysqladmin shutdown':
     mysqladmin. command to stop the slave.

Temporary tables and replication options

By default, all temporary tables are replicated; this happens whether
or not there are any matching `--replicate-do-db',
`--replicate-do-table', or `--replicate-wild-do-table' options in
effect. However, the `--replicate-ignore-table' and
`--replicate-wild-ignore-table' options are honored for temporary
tables.

A recommended practice when using replication is to designate a prefix
for exclusive use in naming temporary tables that you do not want
replicated, then employ a matching `--replicate-wild-ignore-table'
option. For example, you might give all such tables names beginning
with `norep' (such as `norepmytable', `norepyourtable', and so on),
then use `--replicate-wild-ignore-table=norep%' to prevent the
replication of these tables.


File: manual.info,  Node: replication-features-mysqldb,  Next: replication-features-userprivs,  Prev: replication-features-temptables,  Up: replication-features

16.4.1.16 Replication of the `mysql' System Database
....................................................

User privileges are replicated only if the `mysql' database is
replicated. That is, the *Note `GRANT': grant, *Note `REVOKE': revoke,
*Note `SET PASSWORD': set-password, *Note `CREATE USER': create-user,
and *Note `DROP USER': drop-user. statements take effect on the slave
only if the replication setup includes the `mysql' database.


File: manual.info,  Node: replication-features-userprivs,  Next: replication-features-optimizer,  Prev: replication-features-mysqldb,  Up: replication-features

16.4.1.17 Replication and User Privileges
.........................................

User privileges are replicated only if the `mysql' database is
replicated. That is, the *Note `GRANT': grant, *Note `REVOKE': revoke,
*Note `SET PASSWORD': set-password, *Note `CREATE USER': create-user,
and *Note `DROP USER': drop-user. statements take effect on the slave
only if the replication setup includes the `mysql' database.

If you are replicating all databases, but do not want statements that
affect user privileges to be replicated, set up the slave not to
replicate the `mysql' database, using the
`--replicate-wild-ignore-table=mysql.%' option. The slave recognizes
that privilege-related SQL statements have no effect, and thus it does
not execute those statements.


File: manual.info,  Node: replication-features-optimizer,  Next: replication-features-reserved-words,  Prev: replication-features-userprivs,  Up: replication-features

16.4.1.18 Replication and the Query Optimizer
.............................................

It is possible for the data on the master and slave to become different
if a statement is written in such a way that the data modification is
nondeterministic; that is, left up the query optimizer. (In general,
this is not a good practice, even outside of replication.) Examples of
nondeterministic statements include *Note `DELETE': delete. or *Note
`UPDATE': update. statements that use `LIMIT' with no `ORDER BY'
clause; see *Note replication-features-limit::, for a detailed
discussion of these.

Also see *Note bugs::.


File: manual.info,  Node: replication-features-reserved-words,  Next: replication-features-slaveerrors,  Prev: replication-features-optimizer,  Up: replication-features

16.4.1.19 Replication and Reserved Words
........................................

You can encounter problems when you attempt to replicate from an older
master to a newer slave and you make use of identifiers on the master
that are reserved words in the newer MySQL version running on the
slave. An example of this is using a table column named `current_user'
on a 4.0 master that is replicating to a 4.1 or higher slave because
`CURRENT_USER' is a reserved word beginning in MySQL 4.1. Replication
can fail in such cases with Error 1064 `You have an error in your SQL
syntax...', _even if a database or table named using the reserved word
or a table having a column named using the reserved word is excluded
from replication_. This is due to the fact that each SQL event must be
parsed by the slave prior to execution, so that the slave knows which
database object or objects would be affected; only after the event is
parsed can the slave apply any filtering rules defined by
`--replicate-do-db', `--replicate-do-table', `--replicate-ignore-db',
and `--replicate-ignore-table'.

To work around the problem of database, table, or column names on the
master which would be regarded as reserved words by the slave, do one
of the following:

   * Use one or more *Note `ALTER TABLE': alter-table.  statements on
     the master to change the names of any database objects where these
     names would be considered reserved words on the slave, and change
     any SQL statements that use the old names to use the new names
     instead.

   * In any SQL statements using these database object names, write the
     names as quoted identifiers using backtick characters (``').

For listings of reserved words by MySQL version, see Reserved Words
(http://dev.mysql.com/doc/mysqld-version-reference/en/mysqld-version-reference-optvar.html),
in the `MySQL Server Version Reference'. For identifier quoting rules,
see *Note identifiers::.


File: manual.info,  Node: replication-features-slaveerrors,  Next: replication-features-sql-mode,  Prev: replication-features-reserved-words,  Up: replication-features

16.4.1.20 Slave Errors During Replication
.........................................

If a statement produces the same error (identical error code) on both
the master and the slave, the error is logged, but replication
continues.

If a statement produces different errors on the master and the slave,
the slave SQL thread terminates, and the slave writes a message to its
error log and waits for the database administrator to decide what to do
about the error. This includes the case that a statement produces an
error on the master or the slave, but not both. To address the issue,
connect to the slave manually and determine the cause of the problem.
*Note `SHOW SLAVE STATUS': show-slave-status. is useful for this. Then
fix the problem and run *Note `START SLAVE': start-slave. For example,
you might need to create a nonexistent table before you can start the
slave again.

If this error code validation behavior is not desirable, some or all
errors can be masked out (ignored) with the `--slave-skip-errors'
option.

For nontransactional storage engines such as `MyISAM', it is possible
to have a statement that only partially updates a table and returns an
error code.  This can happen, for example, on a multiple-row insert
that has one row violating a key constraint, or if a long update
statement is killed after updating some of the rows. If that happens on
the master, the slave expects execution of the statement to result in
the same error code. If it does not, the slave SQL thread stops as
described previously.

If you are replicating between tables that use different storage
engines on the master and slave, keep in mind that the same statement
might produce a different error when run against one version of the
table, but not the other, or might cause an error for one version of
the table, but not the other. For example, since `MyISAM' ignores
foreign key constraints, an *Note `INSERT': insert. or *Note `UPDATE':
update. statement accessing an `InnoDB' table on the master might cause
a foreign key violation but the same statement performed on a `MyISAM'
version of the same table on the slave would produce no such error,
causing replication to stop.


File: manual.info,  Node: replication-features-sql-mode,  Next: replication-features-timeout,  Prev: replication-features-slaveerrors,  Up: replication-features

16.4.1.21 Replication and Server SQL Mode
.........................................

Using different server SQL mode settings on the master and the slave
may cause the same *Note `INSERT': insert.  statements to be handled
differently on the master and the slave, leading the master and slave
to diverge. For best results, you should always use the same server SQL
mode on the master and on the slave.

For more information, see *Note server-sql-mode::.


File: manual.info,  Node: replication-features-timeout,  Next: replication-features-timestamp,  Prev: replication-features-sql-mode,  Up: replication-features

16.4.1.22 Replication Retries and Timeouts
..........................................

In MySQL 5.0 (starting from 5.0.3), there is a global system variable
`slave_transaction_retries': If the slave SQL thread fails to execute a
transaction because of an `InnoDB' deadlock or because it exceeded the
`InnoDB' `innodb_lock_wait_timeout' or the NDBCLUSTER
`TransactionDeadlockDetectionTimeout' or `TransactionInactiveTimeout'
value, the slave automatically retries the transaction
`slave_transaction_retries' times before stopping with an error. The
default value is 10. Starting from MySQL 5.0.4, the total retry count
can be seen in the output of *Note `SHOW STATUS': show-status.; see
*Note server-status-variables::.


File: manual.info,  Node: replication-features-timestamp,  Next: replication-features-timezone,  Prev: replication-features-timeout,  Up: replication-features

16.4.1.23 Replication and `TIMESTAMP'
.....................................

Older versions of MySQL (prior to 4.1) differed significantly in
several ways in their handling of the *Note `TIMESTAMP': datetime. data
type from what is supported in MySQL versions 5.0 and newer; these
include syntax extensions which are deprecated in MySQL 5.1, and that
no longer supported in MySQL 5.5. This this can cause problems
(including replication failures) when replicating between MySQL Server
versions, if you are using columns that are defined using the old *Note
`TIMESTAMP(N)': datetime. syntax. See *Note
upgrading-from-previous-series::, for more information about the
differences, how they can impact MySQL replication, and what you can do
if you encounter such problems.


File: manual.info,  Node: replication-features-timezone,  Next: replication-features-transactions,  Prev: replication-features-timestamp,  Up: replication-features

16.4.1.24 Replication and Time Zones
....................................

The same system time zone should be set for both master and slave.
Otherwise, statements depending on the local time on the master are not
replicated properly, such as statements that use the `NOW()' or
`FROM_UNIXTIME()' functions. You can set the time zone in which MySQL
server runs by using the `--timezone=TIMEZONE_NAME' option of the
`mysqld_safe' script or by setting the `TZ' environment variable. See
also *Note replication-features-functions::.

If the master is MySQL 4.1 or earlier, both master and slave should
also use the same default connection time zone. That is, the
`--default-time-zone' parameter should have the same value for both
master and slave.

`CONVERT_TZ(...,...,@@session.time_zone)' is properly replicated only
if both master and slave are running MySQL 5.0.4 or newer.


File: manual.info,  Node: replication-features-transactions,  Next: replication-features-triggers,  Prev: replication-features-timezone,  Up: replication-features

16.4.1.25 Replication and Transactions
......................................

Mixing transactional and nontransactional statements within the same
transaction

In general, you should avoid transactions that update both
transactional and nontransactional tables in a replication environment.
You should also avoid using any statement that accesses both
transactional and nontransactional tables and writes to any of them.

In MySQL 5.0 the server uses this rule for binary logging: If the
initial statements in a transaction are nontransactional, they are
written to the binary log immediately. The remaining statements in the
transaction are cached and not written to the binary log until the
transaction is committed. (If the transaction is rolled back, the cached
statements are written to the binary log only if they make
nontransactional changes that cannot be rolled back. Otherwise, they
are discarded.)

To apply this rule, the server considers a statement nontransactional
if the first changes it makes change nontransactional tables,
transactional if the first changes it makes change transactional
tables. `First' applies in the sense that a statement may have several
effects if it involves such things as triggers, stored functions, or
multiple-table updates.

In situations where transactions mix updates to transactional and
nontransactional tables, the order of statements in the binary log is
correct, and all needed statements are written to the binary log even
in case of a *Note `ROLLBACK': commit.  However, when a second
connection updates the nontransactional table before the first
connection transaction is complete, statements can be logged out of
order because the second connection update is written immediately after
it is performed, regardless of the state of the transaction being
performed by the first connection.

Using different storage engines on master and slave

It is possible to replicate transactional tables on the master using
nontransactional tables on the slave. For example, you can replicate an
`InnoDB' master table as a `MyISAM' slave table. However, if you do
this, there are problems if the slave is stopped in the middle of a
*Note `BEGIN': commit ... *Note `COMMIT': commit. block because the
slave restarts at the beginning of the *Note `BEGIN': commit. block.

When the storage engine type of the slave is nontransactional,
transactions on the master that mix updates of transactional and
nontransactional tables should be avoided because they can cause
inconsistency of the data between the master transactional table and
the slave nontransactional table. That is, such transactions can lead
to master storage engine-specific behavior with the possible effect of
replication going out of synchrony. MySQL does not issue a warning
about this currently, so extra care should be taken when replicating
transactional tables from the master to nontransactional tables on the
slaves.

Beginning with MySQL 5.0.56, every transaction (including `autocommit'
transactions) is recorded in the binary log as though it starts with a
*Note `BEGIN': commit.  statement, and ends with either a *Note
`COMMIT': commit. or a *Note `ROLLBACK': commit.  statement. However,
this does _not_ apply to nontransactional changes; any statements
affecting tables using a nontransactional storage engine such as *Note
`MyISAM': myisam-storage-engine. are regarded for this purpose as
nontransactional, even when `autocommit' is enabled. (Bug #26395)


File: manual.info,  Node: replication-features-triggers,  Next: replication-features-views,  Prev: replication-features-transactions,  Up: replication-features

16.4.1.26 Replication and Triggers
..................................

*Known issue*: In MySQL 5.0.17, the syntax for *Note `CREATE TRIGGER':
create-trigger.  changed to include a `DEFINER' clause for specifying
which access privileges to check at trigger invocation time. (See *Note
create-trigger::, for more information.) However, if you attempt to
replicate from a master server older than MySQL 5.0.17 to a slave
running MySQL 5.0.17 through 5.0.19, replication of *Note `CREATE
TRIGGER': create-trigger. statements fails on the slave with a `Definer
not fully qualified' error. A workaround is to create triggers on the
master using a version-specific comment embedded in each *Note `CREATE
TRIGGER': create-trigger. statement:

     CREATE /*!50017 DEFINER = 'root'@'localhost' */ TRIGGER ... ;

*Note `CREATE TRIGGER': create-trigger. statements written this way
will replicate to newer slaves, which pick up the `DEFINER' clause from
the comment and execute successfully.

This slave problem is fixed as of MySQL 5.0.20.


File: manual.info,  Node: replication-features-views,  Next: replication-features-variables,  Prev: replication-features-triggers,  Up: replication-features

16.4.1.27 Replication and Views
...............................

Views are always replicated to slaves. Views are filtered by their own
name, not by the tables they refer to. This means that a view can be
replicated to the slave even if the view contains a table that would
normally be filtered out by `replication-ignore-table' rules. Care
should therefore be taken to ensure that views do not replicate table
data that would normally be filtered for security reasons.


File: manual.info,  Node: replication-features-variables,  Prev: replication-features-views,  Up: replication-features

16.4.1.28 Replication and Variables
...................................

The `foreign_key_checks', `unique_checks', and `sql_auto_is_null'
variables are all replicated.

`sql_mode' is also replicated except for the `NO_DIR_IN_CREATE' mode.
However, when *Note `mysqlbinlog': mysqlbinlog. parses a `SET
@@sql_mode = MODE' statement, the full MODE value, including
`NO_DIR_IN_CREATE', is passed to the receiving server.

The `storage_engine' system variable is not replicated, regardless of
the logging mode; this is intended to facilitate replication between
different storage engines.

The `read_only' system variable is not replicated. In addition, the
enabling this variable has different effects with regard to temporary
tables, table locking, and the *Note `SET PASSWORD': set-password.
statement in different MySQL versions.

Starting from MySQL 5.0.3 (master and slave), replication works even if
the master and slave have different global character set variables.
Starting from MySQL 5.0.4 (master and slave), replication works even if
the master and slave have different global time zone variables.

Session variables are not replicated properly when used in statements
that update tables. For example, the following sequence of statements
will not insert the same data on the master and the slave:

     SET max_join_size=1000;
     INSERT INTO mytable VALUES(@@max_join_size);

This does not apply to the common sequence, which replicates correctly
as of MySQL 5.0.4.

     SET time_zone=...;
     INSERT INTO mytable VALUES(CONVERT_TZ(..., ..., @@time_zone));

Update statements that refer to user-defined variables (that is,
variables of the form `@VAR_NAME') are replicated correctly in MySQL
5.0. However, this is not true for versions prior to 4.1. Note that
user variable names are case insensitive starting in MySQL 5.0. You
should take this into account when setting up replication between MySQL
5.0 and older versions.

In MySQL 5.0.46 and later, the following session variables are written
to the binary log and honored by the replication slave when parsing the
binary log, regardless of the logging format:

   * `sql_mode'

   * `foreign_key_checks'

   * `unique_checks'

   * `character_set_client'

   * `collation_connection'

   * `collation_database'

   * `collation_server'

   * `sql_auto_is_null'

*Important*:

Even though session variables relating to character sets and collations
are written to the binary log, replication between different character
sets is not supported.

It is strongly recommended that you always use the same setting for the
`lower_case_table_names' system variable on both master and slave. In
particular, when a case-sensitive file system is used, and this
variable set to 1 on the slave, but to a different value on the master,
names of databases are not converted to lowercase, which can cause
replication to fail. This is a known issue, which is fixed in MySQL 5.6.


File: manual.info,  Node: replication-compatibility,  Next: replication-upgrade,  Prev: replication-features,  Up: replication-notes

16.4.2 Replication Compatibility Between MySQL Versions
-------------------------------------------------------

MySQL supports replication from one major version to the next higher
major version. For example, you can replicate from a master running
MySQL 4.1 to a slave running MySQL 5.0, from a master running MySQL 5.0
to a slave running MySQL 5.1, and so on.

However, one may encounter difficulties when replicating from an older
master to a newer slave if the master uses statements or relies on
behavior no longer supported in the version of MySQL used on the slave.

The use of more than 2 MySQL Server versions is not supported in
replication setups involving multiple masters, regardless of the number
of master or slave MySQL servers. This restriction applies not only to
major versions, but to minor versions within the same major version as
well. For example, if you are using a chained or circular replication
setup, you cannot use MySQL 5.0.21, MySQL 5.0.22, and MySQL 5.0.24
concurrently, although you could use any 2 of these releases together.

In some cases, it is also possible to replicate between a master and a
slave that is more than one major version newer than the master.
However, there are known issues with trying to replicate from a master
running MySQL 4.1 or earlier to a slave running MySQL 5.1 or later. To
work around such problems, you can insert a MySQL server running an
intermediate version between the two; for example, rather than
replicating directly from a MySQL 4.1 master to a MySQL 5.1 slave, it
is possible to replicate from a MySQL 4.1 server to a MySQL 5.0 server,
and then from the MySQL 5.0 server to a MySQL 5.1 server.

*Important*:

It is strongly recommended to use the most recent release available
within a given MySQL major version because replication (and other)
capabilities are continually being improved. It is also recommended to
upgrade masters and slaves that use early releases of a major version
of MySQL to GA (production) releases when the latter become available
for that major version.

Replication from newer masters to older slaves may be possible, but is
generally not supported. This is due to a number of factors:

   * Binary log format changes

     The binary log format can change between major releases.  While we
     attempt to maintain backward-compatiblity, this is not always
     possible. Major changes were made in MySQL 5.0.3 (for improvements
     to handling of character sets and *Note `LOAD DATA INFILE':
     load-data.) and 5.0.4 (for improvements to handling of time
     zones). Because of these changes, replication from a MySQL 5.0.3
     or later master to a MySQL 5.0.2 or earlier slave is not
     supported. This also means that replication from a MySQL 5.0.3 (or
     later) master to any MySQL 4.1 (or earlier) slave is generally not
     supported.

     This also has significant implications for upgrading replication
     servers; see *Note replication-upgrade::, for more information.

   * Use of row-based replication

     Row-based replication was implemented in MySQL 5.1.5, so you
     cannot replicate using row-based replication from any MySQL 5.0 or
     later master to a slave older than MySQL 5.1.5.

     *Note*:

     Row-based replication is not available in MySQL 5.0. For more
     information about row-based replication in MySQL 5.1, see
     Replication Formats
     (http://dev.mysql.com/doc/refman/5.1/en/replication-formats.html).

   * SQL incompatibilities

     You cannot replicate from a newer master to an older slave using
     statement-based replication if the statements to be replicated use
     SQL features available on the master but not on the slave.

For more information on potential replication issues, see *Note
replication-features::.


File: manual.info,  Node: replication-upgrade,  Next: replication-faq,  Prev: replication-compatibility,  Up: replication-notes

16.4.3 Upgrading a Replication Setup
------------------------------------

When you upgrade servers that participate in a replication setup, the
procedure for upgrading depends on the current server versions and the
version to which you are upgrading.

This section applies to upgrading replication from older versions of
MySQL to MySQL 5.0. A 4.0 server should be 4.0.3 or newer.

When you upgrade a master to 5.0 from an earlier MySQL release series,
you should first ensure that all the slaves of this master are using
the same 5.0.x release. If this is not the case, you should first
upgrade the slaves. To upgrade each slave, shut it down, upgrade it to
the appropriate 5.0.x version, restart it, and restart replication.
The 5.0 slave is able to read the old relay logs written prior to the
upgrade and to execute the statements they contain. Relay logs created
by the slave after the upgrade are in 5.0 format.

After the slaves have been upgraded, shut down the master, upgrade it
to the same 5.0.x release as the slaves, and restart it. The 5.0 master
is able to read the old binary logs written prior to the upgrade and to
send them to the 5.0 slaves. The slaves recognize the old format and
handle it properly. Binary logs created by the master subsequent to the
upgrade are in 5.0 format. These too are recognized by the 5.0 slaves.

In other words, when upgrading to MySQL 5.0, the slaves must be MySQL
5.0 before you can upgrade the master to 5.0. Note that downgrading from
5.0 to older versions does not work so simply: You must ensure that any
5.0 binary log or relay log has been fully processed, so that you can
remove it before proceeding with the downgrade.

Some upgrades may require that you drop and re-create database objects
when you move from one MySQL series to the next. For example, collation
changes might require that table indexes be rebuilt. Such operations,
if necessary, will be detailed at *Note
upgrading-from-previous-series::. It is safest to perform these
operations separately on the slaves and the master, and to disable
replication of these operations from the master to the slave. To
achieve this, use the following procedure:

  1. Stop all the slaves and upgrade them. Restart them with the
     `--skip-slave-start' option so that they do not connect to the
     master. Perform any table repair or rebuilding operations needed
     to re-create database objects, such as use of `REPAIR TABLE' or
     `ALTER TABLE', or dumping and reloading tables or triggers.

  2. Disable the binary log on the master. To do this without
     restarting the master, execute a `SET sql_log_bin = 0' statement.
     Alternatively, stop the master and restart it without the
     `--log-bin' option. If you restart the master, you might also want
     to disallow client connections. For example, if all clients
     connect using TCP/IP, use the `--skip-networking' option when you
     restart the master.

  3. With the binary log disabled, perform any table repair or
     rebuilding operations needed to re-create database objects.  The
     binary log must be disabled during this step to prevent these
     operations from being logged and sent to the slaves later.

  4. Re-enable the binary log on the master. If you set `sql_log_bin'
     to 0 earlier, execute a `SET sql_log_bin = 1' statement. If you
     restarted the master to disable the binary log, restart it with
     `--log-bin', and without `--skip-networking' so that clients and
     slaves can connect.

  5. Restart the slaves, this time without the `--skip-slave-start'
     option.


File: manual.info,  Node: replication-faq,  Next: replication-problems,  Prev: replication-upgrade,  Up: replication-notes

16.4.4 Replication FAQ
----------------------

*Questions*
   * 16.4.4.1: How do I configure a slave if the master is running and
     I do not want to stop it?

   * 16.4.4.2: Must the slave be connected to the master all the time?

   * 16.4.4.3: Must I enable networking on my master and slave to enable
     replication?

   * 16.4.4.4: How do I know how late a slave is compared to the
     master? In other words, how do I know the date of the last
     statement replicated by the slave?

   * 16.4.4.5: How do I force the master to block updates until the
     slave catches up?

   * 16.4.4.6: What issues should I be aware of when setting up two-way
     replication?

   * 16.4.4.7: 

     How can I use replication to improve performance of my system?

   * 16.4.4.8: What should I do to prepare client code in my own
     applications to use performance-enhancing replication?

   * 16.4.4.9: When and how much can MySQL replication improve the
     performance of my system?

   * 16.4.4.10: How do I prevent GRANT and REVOKE statements from
     replicating to slave machines?

   * 16.4.4.11: Does replication work on mixed operating systems (for
     example, the master runs on Linux while slaves run on Mac OS X and
     Windows)?

   * 16.4.4.12: Does replication work on mixed hardware architectures
     (for example, the master runs on a 64-bit machine while slaves run
     on 32-bit machines)?

*Questions and Answers* *16.4.4.1: ** How do I configure a slave if the
master is running and I do not want to stop it?  *

There are several possibilities. If you have taken a snapshot backup of
the master at some point and recorded the binary log file name and
offset (from the output of *Note `SHOW MASTER STATUS':
show-master-status.)  corresponding to the snapshot, use the following
procedure:

  1. Make sure that the slave is assigned a unique server ID.

  2. Execute the following statement on the slave, filling in
     appropriate values for each option:

          mysql> CHANGE MASTER TO
              ->     MASTER_HOST='MASTER_HOST_NAME',
              ->     MASTER_USER='MASTER_USER_NAME',
              ->     MASTER_PASSWORD='MASTER_PASS',
              ->     MASTER_LOG_FILE='RECORDED_LOG_FILE_NAME',
              ->     MASTER_LOG_POS=RECORDED_LOG_POSITION;

  3. Execute *Note `START SLAVE': start-slave. on the slave.

If you do not have a backup of the master server, here is a quick
procedure for creating one. All steps should be performed on the master
host.

  1. Issue this statement to acquire a global read lock:

          mysql> FLUSH TABLES WITH READ LOCK;

  2. With the lock still in place, execute this command (or a variation
     of it):

          shell> tar zcf /tmp/backup.tar.gz /var/lib/mysql

  3. Issue this statement and record the output, which you will need
     later:

          mysql> SHOW MASTER STATUS;

  4. Release the lock:

          mysql> UNLOCK TABLES;

An alternative to using the preceding procedure to make a binary copy
is to make an SQL dump of the master. To do this, you can use *Note
`mysqldump --master-data': mysqldump.  on your master and later load
the SQL dump into your slave.  However, this is slower than making a
binary copy.

Regardless of which of the two methods you use, afterward follow the
instructions for the case when you have a snapshot and have recorded
the log file name and offset. You can use the same snapshot to set up
several slaves. Once you have the snapshot of the master, you can wait
to set up a slave as long as the binary logs of the master are left
intact. The two practical limitations on the length of time you can
wait are the amount of disk space available to retain binary logs on
the master and the length of time it takes the slave to catch up.

*16.4.4.2: ** Must the slave be connected to the master all the time?  *

No, it does not. The slave can go down or stay disconnected for hours
or even days, and then reconnect and catch up on updates. For example,
you can set up a master/slave relationship over a dial-up link where
the link is up only sporadically and for short periods of time. The
implication of this is that, at any given time, the slave is not
guaranteed to be in synchrony with the master unless you take take some
special measures.

To ensure that catchup can occur for a slave that has been
disconnected, you must not remove binary log files from the master that
contain information that has not yet been replicated to the slaves.
Asynchronous replication can work only if the slave is able to continue
reading the binary log from the point where it last read events.

*16.4.4.3: ** Must I enable networking on my master and slave to enable
replication?  *

Yes, networking must be enabled on the master and slave. If networking
is not enabled, the slave cannot connect to the master and transfer the
binary log. Check that the `skip-networking' option has not been
enabled in the configuration file for either server.

*16.4.4.4: ** How do I know how late a slave is compared to the master?
In other words, how do I know the date of the last statement replicated
by the slave?  *

Check the `Seconds_Behind_Master' column in the output from *Note `SHOW
SLAVE STATUS': show-slave-status. See *Note
replication-administration-status::.

When the slave SQL thread executes an event read from the master, it
modifies its own time to the event timestamp.  (This is why *Note
`TIMESTAMP': datetime. is well replicated.) In the `Time' column in the
output of *Note `SHOW PROCESSLIST': show-processlist, the number of
seconds displayed for the slave SQL thread is the number of seconds
between the timestamp of the last replicated event and the real time of
the slave machine. You can use this to determine the date of the last
replicated event. Note that if your slave has been disconnected from
the master for one hour, and then reconnects, you may immediately see
large `Time' values such as 3600 for the slave SQL thread in *Note
`SHOW PROCESSLIST': show-processlist. This is because the slave is
executing statements that are one hour old. See *Note
replication-implementation-details::.

*16.4.4.5: ** How do I force the master to block updates until the slave
catches up?  *

Use the following procedure:

  1. On the master, execute these statements:

          mysql> FLUSH TABLES WITH READ LOCK;
          mysql> SHOW MASTER STATUS;

     Record the replication coordinates (the current binary log file
     name and position) from the output of the *Note `SHOW': show.
     statement.

  2. On the slave, issue the following statement, where the arguments
     to the `MASTER_POS_WAIT()' function are the replication coordinate
     values obtained in the previous step:

          mysql> SELECT MASTER_POS_WAIT('LOG_NAME', LOG_POS);

     The *Note `SELECT': select. statement blocks until the slave
     reaches the specified log file and position. At that point, the
     slave is in synchrony with the master and the statement returns.

  3. On the master, issue the following statement to enable the master
     to begin processing updates again:

          mysql> UNLOCK TABLES;

*16.4.4.6: ** What issues should I be aware of when setting up two-way
replication?  *

MySQL replication currently does not support any locking protocol
between master and slave to guarantee the atomicity of a distributed
(cross-server) update. In other words, it is possible for client A to
make an update to co-master 1, and in the meantime, before it
propagates to co-master 2, client B could make an update to co-master 2
that makes the update of client A work differently than it did on
co-master 1. Thus, when the update of client A makes it to co-master 2,
it produces tables that are different from what you have on co-master
1, even after all the updates from co-master 2 have also propagated.
This means that you should not chain two servers together in a two-way
replication relationship unless you are sure that your updates can
safely happen in any order, or unless you take care of mis-ordered
updates somehow in the client code.

You should also realize that two-way replication actually does not
improve performance very much (if at all) as far as updates are
concerned. Each server must do the same number of updates, just as you
would have a single server do. The only difference is that there is a
little less lock contention because the updates originating on another
server are serialized in one slave thread. Even this benefit might be
offset by network delays.

*16.4.4.7: ** ** ** How can I use replication to improve performance of
my system?  *

Set up one server as the master and direct all writes to it.  Then
configure as many slaves as you have the budget and rackspace for, and
distribute the reads among the master and the slaves. You can also
start the slaves with the `--skip-innodb', `--skip-bdb',
`--low-priority-updates', and `--delay-key-write=ALL' options to get
speed improvements on the slave end. In this case, the slave uses
nontransactional `MyISAM' tables instead of `InnoDB' and `BDB' tables
to get more speed by eliminating transactional overhead.

*16.4.4.8: ** What should I do to prepare client code in my own
applications to use performance-enhancing replication?  *

If the part of your code that is responsible for database access has
been properly abstracted/modularized, converting it to run with a
replicated setup should be very smooth and easy. Change the
implementation of your database access to send all writes to the
master, and to send reads to either the master or a slave. If your code
does not have this level of abstraction, setting up a replicated system
gives you the opportunity and motivation to it clean up. Start by
creating a wrapper library or module that implements the following
functions:

   * `safe_writer_connect()'

   * `safe_reader_connect()'

   * `safe_reader_statement()'

   * `safe_writer_statement()'

`safe_' in each function name means that the function takes care of
handling all error conditions.  You can use different names for the
functions. The important thing is to have a unified interface for
connecting for reads, connecting for writes, doing a read, and doing a
write.

Then convert your client code to use the wrapper library.  This may be
a painful and scary process at first, but it pays off in the long run.
All applications that use the approach just described are able to take
advantage of a master/slave configuration, even one involving multiple
slaves. The code is much easier to maintain, and adding troubleshooting
options is trivial. You need modify only one or two functions; for
example, to log how long each statement took, or which statement among
those issued gave you an error.

If you have written a lot of code, you may want to automate the
conversion task by using the *Note `replace': replace-utility.  utility
that comes with standard MySQL distributions, or write your own
conversion script. Ideally, your code uses consistent programming style
conventions. If not, then you are probably better off rewriting it
anyway, or at least going through and manually regularizing it to use a
consistent style.

*16.4.4.9: ** When and how much can MySQL replication improve the
performance of my system?  *

MySQL replication is most beneficial for a system that processes
frequent reads and infrequent writes. In theory, by using a
single-master/multiple-slave setup, you can scale the system by adding
more slaves until you either run out of network bandwidth, or your
update load grows to the point that the master cannot handle it.

To determine how many slaves you can use before the added benefits
begin to level out, and how much you can improve performance of your
site, you must know your query patterns, and determine empirically by
benchmarking the relationship between the throughput for reads and
writes on a typical master and a typical slave. The example here shows
a rather simplified calculation of what you can get with replication
for a hypothetical system. Let `reads' and `writes' denote the number
of reads and writes per second, respectively.

Let's say that system load consists of 10% writes and 90% reads, and we
have determined by benchmarking that `reads' is 1200 - 2 x `writes'. In
other words, the system can do 1,200 reads per second with no writes,
the average write is twice as slow as the average read, and the
relationship is linear. Suppose that the master and each slave have the
same capacity, and that we have one master and N slaves. Then we have
for each server (master or slave):

`reads' = 1200 - 2 x `writes'

`reads' = 9 x `writes' / (N + 1) (reads are split, but writes
replicated to all slaves)

9 x `writes' / (N + 1) + 2 x `writes' = 1200

`writes' = 1200 / (2 + 9/(N + 1))

The last equation indicates the maximum number of writes for N slaves,
given a maximum possible read rate of 1,200 per minute and a ratio of
nine reads per write.

This analysis yields the following conclusions:

   * If N = 0 (which means we have no replication), our system can
     handle about 1200/11 = 109 writes per second.

   * If N = 1, we get up to 184 writes per second.

   * If N = 8, we get up to 400 writes per second.

   * If N = 17, we get up to 480 writes per second.

   * Eventually, as N approaches infinity (and our budget negative
     infinity), we can get very close to 600 writes per second,
     increasing system throughput about 5.5 times. However, with only
     eight servers, we increase it nearly four times.

Note that these computations assume infinite network bandwidth and
neglect several other factors that could be significant on your system.
In many cases, you may not be able to perform a computation similar to
the one just shown that accurately predicts what will happen on your
system if you add N replication slaves.  However, answering the
following questions should help you decide whether and by how much
replication will improve the performance of your system:

   * What is the read/write ratio on your system?

   * How much more write load can one server handle if you reduce the
     reads?

   * For how many slaves do you have bandwidth available on your
     network?

*16.4.4.10: ** How do I prevent GRANT and REVOKE statements from
replicating to slave machines?  *

Start the server with the `--replicate-wild-ignore-table=mysql.%'
option to ignore replication for tables in the `mysql' database.

*16.4.4.11: ** Does replication work on mixed operating systems (for
example, the master runs on Linux while slaves run on Mac OS X and
Windows)?  *

Yes.

*16.4.4.12: ** Does replication work on mixed hardware architectures
(for example, the master runs on a 64-bit machine while slaves run on
32-bit machines)?  *

Yes.


File: manual.info,  Node: replication-problems,  Next: replication-bugs,  Prev: replication-faq,  Up: replication-notes

16.4.5 Troubleshooting Replication
----------------------------------

If you have followed the instructions but your replication setup is not
working, the first thing to do is _check the error log for messages_.
Many users have lost time by not doing this soon enough after
encountering problems.

If you cannot tell from the error log what the problem was, try the
following techniques:

   * Verify that the master has binary logging enabled by issuing a
     *Note `SHOW MASTER STATUS': show-master-status. statement.  If
     logging is enabled, `Position' is nonzero.  If binary logging is
     not enabled, verify that you are running the master with the
     `--log-bin' option.

   * Verify that the master and slave both were started with the
     `--server-id' option and that the ID value is unique on each
     server.

   * Verify that the slave is running. Use *Note `SHOW SLAVE STATUS':
     show-slave-status. to check whether the `Slave_IO_Running' and
     `Slave_SQL_Running' values are both `Yes'. If not, verify the
     options that were used when starting the slave server. For example,
     `--skip-slave-start' prevents the slave threads from starting
     until you issue a *Note `START SLAVE': start-slave. statement.

   * If the slave is running, check whether it established a connection
     to the master. Use *Note `SHOW PROCESSLIST': show-processlist,
     find the I/O and SQL threads and check their `State' column to see
     what they display. See *Note replication-implementation-details::.
     If the I/O thread state says `Connecting to master', check the
     following:

        * Verify the privileges for the user being used for replication
          on the master.

        * Check that the host name of the master is correct and that
          you are using the correct port to connect to the master.  The
          port used for replication is the same as used for client
          network communication (the default is `3306'). For the host
          name, ensure that the name resolves to the correct IP address.

        * Check that networking has not been disabled on the master or
          slave. Look for the `skip-networking' option in the
          configuration file. If present, comment it out or remove it.

        * If the master has a firewall or IP filtering configuration,
          ensure that the network port being used for MySQL is not
          being filtered.

        * Check that you can reach the master by using `ping' or
          `traceroute'/`tracert' to reach the host.

   * If the slave was running previously but has stopped, the reason
     usually is that some statement that succeeded on the master failed
     on the slave. This should never happen if you have taken a proper
     snapshot of the master, and never modified the data on the slave
     outside of the slave thread. If the slave stops unexpectedly, it
     is a bug or you have encountered one of the known replication
     limitations described in *Note replication-features::. If it is a
     bug, see *Note replication-bugs::, for instructions on how to
     report it.

   * If a statement that succeeded on the master refuses to run on the
     slave, try the following procedure if it is not feasible to do a
     full database resynchronization by deleting the slave's databases
     and copying a new snapshot from the master:

       1. Determine whether the affected table on the slave is
          different from the master table. Try to understand how this
          happened. Then make the slave's table identical to the
          master's and run *Note `START SLAVE': start-slave.

       2. If the preceding step does not work or does not apply, try to
          understand whether it would be safe to make the update
          manually (if needed) and then ignore the next statement from
          the master.

       3. If you decide that the slave can skip the next statement from
          the master, issue the following statements:

               mysql> SET GLOBAL sql_slave_skip_counter = N;
               mysql> START SLAVE;

          The value of N should be 1 if the next statement from the
          master does not use `AUTO_INCREMENT' or `LAST_INSERT_ID()'.
          Otherwise, the value should be 2. The reason for using a
          value of 2 for statements that use `AUTO_INCREMENT' or
          `LAST_INSERT_ID()' is that they take two events in the binary
          log of the master.

          See also *Note set-global-sql-slave-skip-counter::.

       4. If you are sure that the slave started out perfectly
          synchronized with the master, and that no one has updated the
          tables involved outside of the slave thread, then presumably
          the discrepancy is the result of a bug. If you are running
          the most recent version of MySQL, please report the problem.
          If you are running an older version, try upgrading to the
          latest production release to determine whether the problem
          persists.


File: manual.info,  Node: replication-bugs,  Prev: replication-problems,  Up: replication-notes

16.4.6 How to Report Replication Bugs or Problems
-------------------------------------------------

When you have determined that there is no user error involved, and
replication still either does not work at all or is unstable, it is
time to send us a bug report. We need to obtain as much information as
possible from you to be able to track down the bug.  Please spend some
time and effort in preparing a good bug report.

If you have a repeatable test case that demonstrates the bug, please
enter it into our bugs database using the instructions given in *Note
bug-reports::. If you have a `phantom' problem (one that you cannot
duplicate at will), use the following procedure:

  1. Verify that no user error is involved. For example, if you update
     the slave outside of the slave thread, the data goes out of
     synchrony, and you can have unique key violations on updates. In
     this case, the slave thread stops and waits for you to clean up
     the tables manually to bring them into synchrony. _This is not a
     replication problem. It is a problem of outside interference
     causing replication to fail._

  2. Run the slave with the `--log-slave-updates' and `--log-bin'
     options. These options cause the slave to log the updates that it
     receives from the master into its own binary logs.

  3. Save all evidence before resetting the replication state. If we
     have no information or only sketchy information, it becomes
     difficult or impossible for us to track down the problem. The
     evidence you should collect is:

        * All binary log files from the master

        * All binary log files from the slave

        * The output of *Note `SHOW MASTER STATUS': show-master-status.
          from the master at the time you discovered the problem

        * The output of *Note `SHOW SLAVE STATUS': show-slave-status.
          from the slave at the time you discovered the problem

        * Error logs from the master and the slave

  4. Use *Note `mysqlbinlog': mysqlbinlog. to examine the binary logs.
     The following should be helpful to find the problem statement.
     LOG_FILE and LOG_POS are the `Master_Log_File' and
     `Read_Master_Log_Pos' values from *Note `SHOW SLAVE STATUS':
     show-slave-status.

          shell> mysqlbinlog --start-position=LOG_POS LOG_FILE | head

After you have collected the evidence for the problem, try to isolate
it as a separate test case first. Then enter the problem with as much
information as possible into our bugs database using the instructions
at *Note bug-reports::.


File: manual.info,  Node: mysql-cluster,  Next: stored-programs-views,  Prev: replication,  Up: Top

17 MySQL Cluster
****************

* Menu:

* mysql-cluster-overview::       MySQL Cluster Overview
* mysql-cluster-installation::   MySQL Cluster Installation
* mysql-cluster-configuration::  MySQL Cluster Configuration
* mysql-cluster-programs::       MySQL Cluster Programs
* mysql-cluster-management::     Management of MySQL Cluster

This chapter contains information about _MySQL Cluster_ is a
high-availability, high-redundancy version of MySQL adapted for the
distributed computing environment. It uses the *Note `NDBCLUSTER':
mysql-cluster. storage engine to enable running several computers with
MySQL servers and other software in a cluster. This storage engine is
available in MySQL 5.0 binary releases and in RPMs compatible with most
modern Linux distributions.

Supported Platforms

MySQL Cluster is currently available and supported on a number of
platforms. For exact levels of support available for on specific
combinations of operating system versions, operating system
distributions, and hardware platforms, please refer to
http://www.mysql.com/support/supportedplatforms/cluster.html.

Compatibility with standard MySQL

While many standard MySQL schemas and applications can work using MySQL
Cluster, it is also true that unmodified applications and database
schemas may be slightly incompatible or have suboptimal performance
when run using MySQL Cluster (see *Note mysql-cluster-limitations::).
Most of these issues can be overcome, but this also means that you are
very unlikely to be able to switch an existing application
datastore--that currently uses, for example, *Note `MyISAM':
myisam-storage-engine.  or *Note `InnoDB': innodb-storage-engine.--to
use the *Note `NDB': mysql-cluster. storage engine without allowing for
the possibility of changes in schemas, queries, and applications.

Beginning with MySQL Cluster NDB 7.1, MySQL Cluster is available for
production use on Microsoft Windows. MySQL Cluster is not available for
Microsoft Windows in MySQL 5.0. For more information, see MySQL Cluster
NDB 6.X/7.X (http://dev.mysql.com/doc/refman/5.1/en/mysql-cluster.html).

This chapter represents a work in progress, and its contents are
subject to revision as MySQL Cluster continues to evolve. Additional
information regarding MySQL Cluster can be found on the MySQL Web site
at http://www.mysql.com/products/cluster/.

Additional Resources

More information may be found in the following places:

   * Answers to some commonly asked questions about Cluster may be
     found in the *Note faqs-mysql-cluster::.

   * The MySQL Cluster mailing list: `http://lists.mysql.com/cluster'.

   * The MySQL Cluster Forum: `http://forums.mysql.com/list.php?25'.

   * Many MySQL Cluster users and some of the MySQL Cluster developers
     blog about their experiences with Cluster, and make feeds of these
     available through PlanetMySQL (http://www.planetmysql.org/).

   * If you are new to MySQL Cluster, you may find our Developer Zone
     article How to set up a MySQL Cluster for two servers
     (http://dev.mysql.com/tech-resources/articles/mysql-cluster-for-two-servers.html)
     to be helpful.


File: manual.info,  Node: mysql-cluster-overview,  Next: mysql-cluster-installation,  Prev: mysql-cluster,  Up: mysql-cluster

17.1 MySQL Cluster Overview
===========================

* Menu:

* mysql-cluster-basics::         MySQL Cluster Core Concepts
* mysql-cluster-nodes-groups::   MySQL Cluster Nodes, Node Groups, Replicas, and Partitions
* mysql-cluster-overview-requirements::  MySQL Cluster Hardware, Software, and Networking Requirements
* mysql-cluster-development::    MySQL Cluster Development History
* mysql-cluster-limitations::    Known Limitations of MySQL Cluster

_MySQL Cluster_ is a technology that enables clustering of in-memory
databases in a shared-nothing system. The shared-nothing architecture
enables the system to work with very inexpensive hardware, and with a
minimum of specific requirements for hardware or software.

MySQL Cluster is designed not to have any single point of failure.  In
a shared-nothing system, each component is expected to have its own
memory and disk, and the use of shared storage mechanisms such as
network shares, network file systems, and SANs is not recommended or
supported.

MySQL Cluster integrates the standard MySQL server with an in-memory
clustered storage engine called *Note `NDB': mysql-cluster.  (which
stands for `_N_etwork _D_ata_B_ase'). In our documentation, the term
*Note `NDB': mysql-cluster. refers to the part of the setup that is
specific to the storage engine, whereas `MySQL Cluster' refers to the
combination of one or more MySQL servers with the *Note `NDB':
mysql-cluster.  storage engine.

A MySQL Cluster consists of a set of computers, known as _hosts_, each
running one or more processes.  These processes, known as _nodes_, may
include MySQL servers (for access to NDB data), data nodes (for storage
of the data), one or more management servers, and possibly other
specialized data access programs. The relationship of these components
in a MySQL Cluster is shown here:

MySQL Cluster Components

All these programs work together to form a MySQL Cluster (see *Note
mysql-cluster-programs::. When data is stored by the *Note `NDB':
mysql-cluster. storage engine, the tables (and table data) are stored
in the data nodes. Such tables are directly accessible from all other
MySQL servers (SQL nodes) in the cluster.  Thus, in a payroll
application storing data in a cluster, if one application updates the
salary of an employee, all other MySQL servers that query this data can
see this change immediately.

However, a MySQL server that is not connected to a MySQL Cluster cannot
use the *Note `NDB': mysql-cluster. storage engine and cannot access
any MySQL Cluster data.

The data stored in the data nodes for MySQL Cluster can be mirrored;
the cluster can handle failures of individual data nodes with no other
impact than that a small number of transactions are aborted due to
losing the transaction state. Because transactional applications are
expected to handle transaction failure, this should not be a source of
problems.

Individual nodes can be stopped and restarted, and can then rejoin the
system (cluster). Rolling restarts (in which all nodes are restarted in
turn) are used in making configuration changes and software upgrades
(see *Note mysql-cluster-rolling-restart::). For more information about
data nodes, how they are organized in a MySQL Cluster, and how they
handle and store MySQL Cluster data, see *Note
mysql-cluster-nodes-groups::.

Backing up and restoring MySQL Cluster databases can be done using the
NDB native functionality found in the MySQL Cluster management client
and the *Note `ndb_restore': mysql-cluster-programs-ndb-restore.
program included in the MySQL Cluster distribution. For more
information, see *Note mysql-cluster-backup::, and *Note
mysql-cluster-programs-ndb-restore::. You can also use the standard
MySQL functionality provided for this purpose in *Note `mysqldump':
mysqldump. and the MySQL server. See *Note mysqldump::, for more
information.

MySQL Cluster nodes can use a number of different transport mechanisms
for inter-node communications, including TCP/IP using standard 100 Mbps
or faster Ethernet hardware. It is also possible to use the high-speed
_Scalable Coherent Interface_ (SCI) protocol with MySQL Cluster,
although this is not required to use MySQL Cluster. SCI requires special
hardware and software; see *Note mysql-cluster-interconnects::, for
more about SCI and using it with MySQL Cluster.


File: manual.info,  Node: mysql-cluster-basics,  Next: mysql-cluster-nodes-groups,  Prev: mysql-cluster-overview,  Up: mysql-cluster-overview

17.1.1 MySQL Cluster Core Concepts
----------------------------------

_*Note `NDBCLUSTER': mysql-cluster._ (also known as *Note `NDB':
mysql-cluster.) is an in-memory storage engine offering
high-availability and data-persistence features.

The *Note `NDBCLUSTER': mysql-cluster. storage engine can be configured
with a range of failover and load-balancing options, but it is easiest
to start with the storage engine at the cluster level. MySQL Cluster's
*Note `NDB': mysql-cluster. storage engine contains a complete set of
data, dependent only on other data within the cluster itself.

The `Cluster' portion of MySQL Cluster is configured independently of
the MySQL servers. In a MySQL Cluster, each part of the cluster is
considered to be a _node_.

*Note*:

In many contexts, the term `node' is used to indicate a computer, but
when discussing MySQL Cluster it means a _process_. It is possible to
run multiple nodes on a single computer; for a computer on which one or
more cluster nodes are being run we use the term _cluster host_.

However, MySQL 5.0 does not support the use of multiple data nodes on a
single computer in a production setting. See *Note
mysql-cluster-limitations-multiple-nodes::.

There are three types of cluster nodes, and in a minimal MySQL Cluster
configuration, there will be at least three nodes, one of each of these
types:

   * _Management node_ (MGM node): The role of this type of node is to
     manage the other nodes within the MySQL Cluster, performing such
     functions as providing configuration data, starting and stopping
     nodes, running backup, and so forth. Because this node type
     manages the configuration of the other nodes, a node of this type
     should be started first, before any other node. An MGM node is
     started with the command *Note `ndb_mgmd':
     mysql-cluster-programs-ndb-mgmd.

   * _Data node_: This type of node stores cluster data. There are as
     many data nodes as there are replicas, times the number of
     fragments (see *Note mysql-cluster-nodes-groups::). For example,
     with two replicas, each having two fragments, you need four data
     nodes. One replica is sufficient for data storage, but provides no
     redundancy; therefore, it is recommended to have 2 (or more)
     replicas to provide redundancy, and thus high availability. A data
     node is started with the command *Note `ndbd':
     mysql-cluster-programs-ndbd. (see *Note
     mysql-cluster-programs-ndbd::).

     MySQL Cluster tables in MySQL 5.0 are stored completely in memory
     rather than on disk (this is why we refer to MySQL cluster as an
     _in-memory_ database). In MySQL 5.1, MySQL Cluster NDB 6.X, and
     later, some MySQL Cluster data can be stored on disk, but we do not
     expect to backport this functionality to MySQL 5.0; see MySQL
     Cluster Disk Data Tables
     (http://dev.mysql.com/doc/refman/5.1/en/mysql-cluster-disk-data.html),
     for more information.

   * _SQL node_: This is a node that accesses the cluster data. In the
     case of MySQL Cluster, an SQL node is a traditional MySQL server
     that uses the *Note `NDBCLUSTER': mysql-cluster. storage engine.
     An SQL node is a *Note `mysqld': mysqld. process started with the
     `--ndbcluster' and `--ndb-connectstring' options, which are
     explained elsewhere in this chapter, possibly with additional
     MySQL server options as well.

     An SQL node is actually just a specialized type of _API node_,
     which designates any application which accesses Cluster data.
     Another example of an API node is the *Note `ndb_restore':
     mysql-cluster-programs-ndb-restore. utility that is used to
     restore a cluster backup. It is possible to write such
     applications using the NDB API. For basic information about the
     NDB API, see Getting Started with the NDB API
     (http://dev.mysql.com/doc/ndbapi/en/ndb-getting-started.html#ndb-getting-started).

*Important*:

It is not realistic to expect to employ a three-node setup in a
production environment. Such a configuration provides no redundancy; to
benefit from MySQL Cluster's high-availability features, you must use
multiple data and SQL nodes. The use of multiple management nodes is
also highly recommended.

For a brief introduction to the relationships between nodes, node
groups, replicas, and partitions in MySQL Cluster, see *Note
mysql-cluster-nodes-groups::.

Configuration of a cluster involves configuring each individual node in
the cluster and setting up individual communication links between
nodes. MySQL Cluster is currently designed with the intention that data
nodes are homogeneous in terms of processor power, memory space, and
bandwidth. In addition, to provide a single point of configuration, all
configuration data for the cluster as a whole is located in one
configuration file.

The management server (MGM node) manages the cluster configuration file
and the cluster log. Each node in the cluster retrieves the
configuration data from the management server, and so requires a way to
determine where the management server resides. When interesting events
occur in the data nodes, the nodes transfer information about these
events to the management server, which then writes the information to
the cluster log.

In addition, there can be any number of cluster client processes or
applications. These are of two types:

   * Standard MySQL clients

     MySQL Cluster can be used with existing MySQL applications written
     in PHP, Perl, C, C++, Java, Python, Ruby, and so on.  Such client
     applications send SQL statements to and receive responses from
     MySQL servers acting as MySQL Cluster SQL nodes in much the same
     way that they interact with standalone MySQL servers. However,
     MySQL clients using a MySQL Cluster as a data source can be
     modified to take advantage of the ability to connect with multiple
     MySQL servers to achieve load balancing and failover. For example,
     Java clients using Connector/J 5.0.6 and later can use
     `jdbc:mysql:loadbalance://' URLs (improved in Connector/J 5.1.7)
     to achieve load balancing transparently

     .

   * Management clients

     These clients connect to the management server and provide
     commands for starting and stopping nodes gracefully, starting and
     stopping message tracing (debug versions only), showing node
     versions and status, starting and stopping backups, and so on.
     Such clients--such as the *Note `ndb_mgm':
     mysql-cluster-programs-ndb-mgm. management client supplied with
     MySQL Cluster (see *Note mysql-cluster-programs-ndb-mgm::)--are
     written using the MGM API, a C-language API that communicates
     directly with one or more MySQL Cluster management servers. For
     more information, see The MGM API
     (http://dev.mysql.com/doc/ndbapi/en/mgm-api.html).

Event logs

MySQL Cluster logs events by category (startup, shutdown, errors,
checkpoints, and so on), priority, and severity. A complete listing of
all reportable events may be found in *Note
mysql-cluster-event-reports::. Event logs are of two types:

   * Cluster log

     Keeps a record of all desired reportable events for the cluster as
     a whole.

   * Node log

     A separate log which is also kept for each individual node.

*Note*:

Under normal circumstances, it is necessary and sufficient to keep and
examine only the cluster log. The node logs need be consulted only for
application development and debugging purposes.

Checkpoint

Generally speaking, when data is saved to disk, it is said that a
checkpoint has been reached. More specific to Cluster, it is a point in
time where all committed transactions are stored on disk. With regard
to the *Note `NDB': mysql-cluster.  storage engine, there are two types
of checkpoints which work together to ensure that a consistent view of
the cluster's data is maintained:

   * Local Checkpoint (LCP)

     This is a checkpoint that is specific to a single node; however,
     LCP's take place for all nodes in the cluster more or less
     concurrently. An LCP involves saving all of a node's data to disk,
     and so usually occurs every few minutes. The precise interval
     varies, and depends upon the amount of data stored by the node,
     the level of cluster activity, and other factors.

   * Global Checkpoint (GCP)

     A GCP occurs every few seconds, when transactions for all nodes
     are synchronized and the redo-log is flushed to disk.


File: manual.info,  Node: mysql-cluster-nodes-groups,  Next: mysql-cluster-overview-requirements,  Prev: mysql-cluster-basics,  Up: mysql-cluster-overview

17.1.2 MySQL Cluster Nodes, Node Groups, Replicas, and Partitions
-----------------------------------------------------------------

This section discusses the manner in which MySQL Cluster divides and
duplicates data for storage.

Central to an understanding of this topic are the following concepts,
listed here with brief definitions:

   * (Data) Node

     An *Note `ndbd': mysql-cluster-programs-ndbd. process, which
     stores a _replica_ --that is, a copy of the _partition_ (see
     below) assigned to the node group of which the node is a member.

     Each data node should be located on a separate computer. While it
     is also possible to host multiple *Note `ndbd':
     mysql-cluster-programs-ndbd.  processes on a single computer, such
     a configuration is not supported.

     It is common for the terms `node' and `data node' to be used
     interchangeably when referring to an *Note `ndbd':
     mysql-cluster-programs-ndbd. process; where mentioned, management
     (MGM) nodes (*Note `ndb_mgmd': mysql-cluster-programs-ndb-mgmd.
     processes) and SQL nodes (*Note `mysqld': mysqld. processes) are
     specified as such in this discussion.

   * Node Group

     A node group consists of one or more nodes, and stores partitions,
     or sets of _replicas_ (see next item).

     The number of node groups in a MySQL Cluster is not directly
     configurable; it is function of the number of data nodes and of
     the number of replicas (`NoOfReplicas' configuration parameter),
     as shown here:

          [NUMBER_OF_NODE_GROUPS] = NUMBER_OF_DATA_NODES / `NoOfReplicas'

     Thus, a MySQL Cluster with 4 data nodes has 4 node groups if
     `NoOfReplicas' is set to 1 in the `config.ini' file, 2 node groups
     if `NoOfReplicas' is set to 2, and 1 node group if `NoOfReplicas'
     is set to 4. Replicas are discussed later in this section; for
     more information about `NoOfReplicas', see *Note
     mysql-cluster-ndbd-definition::.

     *Note*:

     All node groups in a MySQL Cluster must have the same number of
     data nodes.

   * Partition

     This is a portion of the data stored by the cluster. There are as
     many cluster partitions as nodes participating in the cluster.
     Each node is responsible for keeping at least one copy of any
     partitions assigned to it (that is, at least one replica)
     available to the cluster.

     A replica belongs entirely to a single node; a node can (and
     usually does) store several replicas.

   * Replica

     This is a copy of a cluster partition. Each node in a node group
     stores a replica. Also sometimes known as a _partition replica_.
     The number of replicas is equal to the number of nodes per node
     group.

The following diagram illustrates a MySQL Cluster with four data nodes,
arranged in two node groups of two nodes each; nodes 1 and 2 belong to
node group 0, and nodes 3 and 4 belong to node group 1. Note that only
data (*Note `ndbd': mysql-cluster-programs-ndbd.) nodes are shown here;
although a working cluster requires an *Note `ndb_mgm':
mysql-cluster-programs-ndb-mgm. process for cluster management and at
least one SQL node to access the data stored by the cluster, these have
been omitted in the figure for clarity.

A MySQL Cluster, with 2 node groups having 2 nodes each

The data stored by the cluster is divided into four partitions,
numbered 0, 1, 2, and 3. Each partition is stored--in multiple
copies--on the same node group. Partitions are stored on alternate node
groups:

   * Partition 0 is stored on node group 0; a _primary replica_
     (primary copy) is stored on node 1, and a _backup replica_ (backup
     copy of the partition) is stored on node 2.

   * Partition 1 is stored on the other node group (node group 1); this
     partition's primary replica is on node 3, and its backup replica
     is on node 4.

   * Partition 2 is stored on node group 0. However, the placing of its
     two replicas is reversed from that of Partition 0; for Partition
     2, the primary replica is stored on node 2, and the backup on node
     1.

   * Partition 3 is stored on node group 1, and the placement of its
     two replicas are reversed from those of partition 1. That is, its
     primary replica is located on node 4, with the backup on node 3.

What this means regarding the continued operation of a MySQL Cluster is
this: so long as each node group participating in the cluster has at
least one node operating, the cluster has a complete copy of all data
and remains viable. This is illustrated in the next diagram.

Nodes required to keep a 2x2 cluster viable

In this example, where the cluster consists of two node groups of two
nodes each, any combination of at least one node in node group 0 and at
least one node in node group 1 is sufficient to keep the cluster
`alive' (indicated by arrows in the diagram).  However, if _both_ nodes
from _either_ node group fail, the remaining two nodes are not
sufficient (shown by the arrows marked out with an *X*); in either
case, the cluster has lost an entire partition and so can no longer
provide access to a complete set of all cluster data.


File: manual.info,  Node: mysql-cluster-overview-requirements,  Next: mysql-cluster-development,  Prev: mysql-cluster-nodes-groups,  Up: mysql-cluster-overview

17.1.3 MySQL Cluster Hardware, Software, and Networking Requirements
--------------------------------------------------------------------

One of the strengths of MySQL Cluster is that it can be run on
commodity hardware and has no unusual requirements in this regard,
other than for large amounts of RAM, due to the fact that all live data
storage is done in memory. (It is possible to reduce this requirement
using Disk Data tables, which are implemented in MySQL 5.1; however, we
do not intend to backport this feature to MySQL 5.0.) Naturally,
multiple and faster CPUs will enhance performance. Memory requirements
for other MySQL Cluster processes are relatively small.

The software requirements for MySQL Cluster are also modest. Host
operating systems do not require any unusual modules, services,
applications, or configuration to support MySQL Cluster. For supported
operating systems, a standard installation should be sufficient. The
MySQL software requirements are simple: all that is needed is a
production release of MySQL 5.0 to have Cluster support. It is not
necessary to compile MySQL yourself merely to be able to use MySQL
Cluster. We assume that you are using the server binary appropriate to
your platform, available from the MySQL Cluster software downloads page
at `http://dev.mysql.com/downloads/cluster/'.

For communication between nodes, MySQL Cluster supports TCP/IP
networking in any standard topology, and the minimum expected for each
host is a standard 100 Mbps Ethernet card, plus a switch, hub, or
router to provide network connectivity for the cluster as a whole. We
strongly recommend that a MySQL Cluster be run on its own subnet which
is not shared with machines not forming part of the cluster for the
following reasons:

   * Security

     Communications between MySQL Cluster nodes are not encrypted or
     shielded in any way. The only means of protecting transmissions
     within a MySQL Cluster is to run the cluster on a protected
     network. If you intend to use MySQL Cluster for Web applications,
     the cluster should definitely reside behind your firewall and not
     in your network's De-Militarized Zone (DMZ
     (http://compnetworking.about.com/cs/networksecurity/g/bldef_dmz.htm))
     or elsewhere.

     See *Note mysql-cluster-security-networking-issues::, for more
     information.

   * Efficiency

     Setting up a MySQL Cluster on a private or protected network
     enables the cluster to make exclusive use of bandwidth between
     cluster hosts. Using a separate switch for your MySQL Cluster not
     only helps protect against unauthorized access to cluster data, it
     also ensures that MySQL Cluster nodes are shielded from
     interference caused by transmissions between other computers on
     the network. For enhanced reliability, you can use dual switches
     and dual cards to remove the network as a single point of failure;
     many device drivers support failover for such communication links.

Network communication and latency

MySQL Cluster requires communication between data nodes and API nodes
(including SQL nodes), as well as between data nodes and other data
nodes, to execute queries and updates. Communication latency between
these processes can directly affect the observed performance and
latency of user queries. In addition, to maintain consistency and
service despite the silent failure of nodes, MySQL Cluster uses
heartbeating and timeout mechanisms which treat an extended loss of
communication from a node as node failure. This can lead to reduced
redundancy. Recall that, to maintain data consistency, a MySQL Cluster
shuts down when the last node in a node group fails. Thus, to avoid
increasing the risk of a forced shutdown, breaks in communication
between nodes should be avoided wherever possible.

The failure of a data or API node results in the abort of all
uncommitted transactions involving the failed node. Data node recovery
requires synchronization of the failed notde's data from a surviving
data node, and re-establishment of disk-based redo and checkpoint logs,
before the data node returns to service.  This recovery can take some
time, during which the Cluster operates with reduced redundancy.

Heartbeating relies on timely generation of heartbeat signals by all
nodes. This may not be possible if the node is overloaded, has
insufficient machine CPU due to sharing with other programs, or is
experiencing delays due to swapping. If heartbeat generation is
sufficiently delayed, other nodes treat the node that is slow to
respond as failed.

This treatment of a slow node as a failed one may or may not be
desireable in some circumstances, depending on the impact of the node's
slowed operation on the rest of the cluster. When setting timeout
values such as `HeartbeatIntervalDbDb' and `HeartbeatIntervalDbApi' for
MySQL Cluster, care must be taken care to achieve quick detection,
failover, and return to service, while avoiding potentially expensive
false positives.

Where communication latencies between data nodes are expected to be
higher than would be expected in a LAN environment (on the order of 100
µs), timeout parameters must be increased to ensure that any allowed
periods of latency periods are well within configured timeouts.
Increasing timeouts in this way has a corresponding effect on the
worst-case time to detect failure and therefore time to service
recovery.

LAN environments can typically be configured with stable low latency,
and such that they can provide redundancy with fast failover.
Individual link failures can be recovered from with minimal and
controlled latency visible at the TCP level (where MySQL Cluster
normally operates). WAN environments may offer a range of latencies, as
well as redundancy with slower failover times. Individual link failures
may require route changes to propagate before end-to-end connectivity
is restored. At the TCP level this can appear as large latencies on
individual channels.  The worst-case observed TCP latency in these
scenarios is related to the worst-case time for the IP layer to reroute
around the failures.

SCI support

It is also possible to use the high-speed Scalable Coherent Interface
(SCI) with MySQL Cluster, but this is not a requirement. See *Note
mysql-cluster-interconnects::, for more about this protocol and its use
with MySQL Cluster.


File: manual.info,  Node: mysql-cluster-development,  Next: mysql-cluster-limitations,  Prev: mysql-cluster-overview-requirements,  Up: mysql-cluster-overview

17.1.4 MySQL Cluster Development History
----------------------------------------

* Menu:

* mysql-cluster-development-5-0::  MySQL Cluster Developement in MySQL 5.0

In this section, we discuss changes in the implementation of MySQL
Cluster in MySQL 5.0 as compared to MySQL 4.1.

There are relatively few changes between the NDB storage engine
implementations in MySQL 4.1 and in 5.0, so the upgrade path should be
relatively quick and painless.

All significantly new features being developed for MySQL Cluster are
going into the MySQL Cluster NDB 7.x trees. For information on changes
in the Cluster implementations in MySQL versions 5.1 and later, see
*Note mysql-cluster-development::.


File: manual.info,  Node: mysql-cluster-development-5-0,  Prev: mysql-cluster-development,  Up: mysql-cluster-development

17.1.4.1 MySQL Cluster Developement in MySQL 5.0
................................................

MySQL Cluster in MySQL 5.0 contains a number of features added since
MySQL 4.1 that are likely to be of interest:

   * Condition pushdown

     Consider the following query:

          SELECT * FROM t1 WHERE non_indexed_attribute = 1;

     This query uses a full table scan and the condition is evaluated
     in the cluster's data nodes. Thus, it is not necessary to send the
     records across the network for evaluation. (That is, function
     transport is used, rather than data transport.) Please note that
     this feature is currently disabled by default (pending more
     thorough testing), but it should work in most cases. This feature
     can be enabled through the use of the `SET
     engine_condition_pushdown = On' statement.  Alternatively, you can
     run *Note `mysqld': mysqld. with the this feature enabled by
     starting the MySQL server with the `--engine-condition-pushdown'
     option.

     A major benefit of this change is that queries can be executed in
     parallel. This means that queries against nonindexed columns can
     run faster than previously by a factor of as much as 5 to 10
     times, _times the number of data nodes_, because multiple CPUs can
     work on the query in parallel.

     You can use *Note `EXPLAIN': explain. to determine when condition
     pushdown is being used. See *Note explain::.

   * *Decreased `IndexMemory' Usage*: In MySQL 5.0, each record
     consumes approximately 25 bytes of index memory, and every unique
     index uses 25 bytes per record of index memory (in addition to
     some data memory because these are stored in a separate table).
     This is because the primary key is not stored in the index memory
     anymore.

   * *Query Cache Enabled for MySQL Cluster*: See *Note query-cache::,
     for information on configuring and using the query cache.

   * New optimizations

     One optimization that merits particular attention is that a
     batched read interface is now used in some queries. For example,
     consider the following query:

          SELECT * FROM t1 WHERE PRIMARY_KEY IN (1,2,3,4,5,6,7,8,9,10);

     This query will be executed 2 to 3 times more quickly than in
     previous MySQL Cluster versions due to the fact that all 10 key
     lookups are sent in a single batch rather than one at a time.

   * *Limit On Number of Metadata Objects*: Beginning with MySQL 5.0.6,
     each Cluster database may contain a maximum of 20320 metadata
     objects--this includes database tables, system tables, indexes and
     *Note `BLOB': blob. values.  (Previously, this number was 1600.)


File: manual.info,  Node: mysql-cluster-limitations,  Prev: mysql-cluster-development,  Up: mysql-cluster-overview

17.1.5 Known Limitations of MySQL Cluster
-----------------------------------------

* Menu:

* mysql-cluster-limitations-syntax::  Noncompliance with SQL Syntax in MySQL Cluster
* mysql-cluster-limitations-limits::  Limits and Differences of MySQL Cluster from Standard MySQL Limits
* mysql-cluster-limitations-transactions::  Limits Relating to Transaction Handling in MySQL Cluster
* mysql-cluster-limitations-error-handling::  MySQL Cluster Error Handling
* mysql-cluster-limitations-database-objects::  Limits Associated with Database Objects in MySQL Cluster
* mysql-cluster-limitations-unsupported::  Unsupported or Missing Features in MySQL Cluster
* mysql-cluster-limitations-performance::  Limitations Relating to Performance in MySQL Cluster
* mysql-cluster-limitations-exclusive-to-cluster::  Issues Exclusive to MySQL Cluster
* mysql-cluster-limitations-multiple-nodes::  Limitations Relating to Multiple MySQL Cluster Nodes
* mysql-cluster-limitations-resolved::  Previous MySQL Cluster Issues Resolved in MySQL 5.0

In the sections that follow, we discuss known limitations of MySQL
Cluster in MySQL 5.0 as compared with the features available when using
the `MyISAM' and `InnoDB' storage engines. Currently, there are no
plans to address these in coming releases of MySQL 5.0; however, we
will attempt to supply fixes for these issues in subsequent release
series. If you check the `Cluster' category in the MySQL bugs database
at `http://bugs.mysql.com', you can find known bugs in the following
categories under `MySQL Server:' in the MySQL bugs database at
`http://bugs.mysql.com', which we intend to correct in upcoming
releases of MySQL Cluster:

   * Cluster

   * Cluster Direct API (NDBAPI)

   * Cluster Disk Data

   * Cluster Replication

This information is intended to be complete with respect to the
conditions just set forth. You can report any discrepancies that you
encounter to the MySQL bugs database using the instructions given in
*Note bug-reports::. If we do not plan to fix the problem in MySQL 5.0,
we will add it to the list.

See *Note mysql-cluster-limitations-resolved:: for a list of issues in
MySQL Cluster in MySQL 4.1 that have been resolved in the current
version.


File: manual.info,  Node: mysql-cluster-limitations-syntax,  Next: mysql-cluster-limitations-limits,  Prev: mysql-cluster-limitations,  Up: mysql-cluster-limitations

17.1.5.1 Noncompliance with SQL Syntax in MySQL Cluster
.......................................................

Some SQL statements relating to certain MySQL features produce errors
when used with *Note `NDB': mysql-cluster. tables, as described in the
following list:

   * Temporary tables

     Temporary tables are not supported. Trying either to create a
     temporary table that uses the *Note `NDB': mysql-cluster. storage
     engine or to alter an existing temporary table to use *Note `NDB':
     mysql-cluster. fails with the error `Table storage engine
     'ndbcluster' does not support the create option 'TEMPORARY''.

   * Indexes and keys in `NDB' tables

     Keys and indexes on MySQL Cluster tables are subject to the
     following limitations:

        * Column width

          Attempting to create an index on an `NDB' table column whose
          width is greater than 3072 bytes succeeds, but only the first
          3072 bytes are actually used for the index. In such cases, a
          warning `Specified key was too long; max key length is 3072
          bytes' is issued, and a *Note `SHOW CREATE TABLE':
          show-create-table. statement shows the length of the index as
          3072.

        * `TEXT' and `BLOB' columns

          You cannot create indexes on *Note `NDB': mysql-cluster.
          table columns that use any of the *Note `TEXT': blob. or
          *Note `BLOB': blob. data types.

        * `FULLTEXT' indexes

          The *Note `NDB': mysql-cluster. storage engine does not
          support `FULLTEXT' indexes, which are possible for `MyISAM'
          tables only.

          However, you can create indexes on *Note `VARCHAR': char.
          columns of *Note `NDB': mysql-cluster. tables.

        * `USING HASH' keys and `NULL'

          Using nullable columns in unique keys and primary keys means
          that queries using these columns are handled as full table
          scans. To work around this issue, make the column `NOT NULL',
          or re-create the index without the `USING HASH' option.

        * Prefixes

          There are no prefix indexes; only entire columns can be
          indexed. (The size of an `NDB' column index is always the
          same as the width of the column in bytes, up to and including
          3072 bytes, as described earlier in this section. Also see
          *Note mysql-cluster-limitations-unsupported::, for additional
          information.)

        * `BIT' columns

          A *Note `BIT': numeric-types. column cannot be a primary key,
          unique key, or index, nor can it be part of a composite
          primary key, unique key, or index.

        * `AUTO_INCREMENT' columns

          Like other MySQL storage engines, the *Note `NDB':
          mysql-cluster. storage engine can handle a maximum of one
          `AUTO_INCREMENT' column per table.  However, in the case of a
          Cluster table with no explicit primary key, an
          `AUTO_INCREMENT' column is automatically defined and used as a
          `hidden' primary key. For this reason, you cannot define a
          table that has an explicit `AUTO_INCREMENT' column unless that
          column is also declared using the `PRIMARY KEY' option.
          Attempting to create a table with an `AUTO_INCREMENT' column
          that is not the table's primary key, and using the *Note
          `NDB': mysql-cluster. storage engine, fails with an error.

   * MySQL Cluster and geometry data types

     Geometry data types (`WKT' and `WKB') are supported in *Note
     `NDB': mysql-cluster. tables in MySQL 5.0. However, spatial
     indexes are not supported.


File: manual.info,  Node: mysql-cluster-limitations-limits,  Next: mysql-cluster-limitations-transactions,  Prev: mysql-cluster-limitations-syntax,  Up: mysql-cluster-limitations

17.1.5.2 Limits and Differences of MySQL Cluster from Standard MySQL Limits
...........................................................................

In this section, we list limits found in MySQL Cluster that either
differ from limits found in, or that are not found in, standard MySQL.

Memory usage and recovery

Memory consumed when data is inserted into an *Note `NDB':
mysql-cluster. table is not automatically recovered when deleted, as it
is with other storage engines.  Instead, the following rules hold true:

   * A *Note `DELETE': delete. statement on an *Note `NDB':
     mysql-cluster. table makes the memory formerly used by the deleted
     rows available for re-use by inserts on the same table only.
     However, this memory can be made available for general re-use by
     performing a rolling restart of the cluster. See *Note
     mysql-cluster-rolling-restart::.

   * A *Note `DROP TABLE': drop-table. or *Note `TRUNCATE TABLE':
     truncate-table. operation on an *Note `NDB': mysql-cluster. table
     frees the memory that was used by this table for re-use by any
     *Note `NDB': mysql-cluster. table, either by the same table or by
     another *Note `NDB': mysql-cluster. table.

     *Note*:

     Recall that *Note `TRUNCATE TABLE': truncate-table.  drops and
     re-creates the table. See *Note truncate-table::.

   * Limits imposed by the cluster's configuration

     A number of hard limits exist which are configurable, but
     available main memory in the cluster sets limits. See the complete
     list of configuration parameters in *Note
     mysql-cluster-config-file::. Most configuration parameters can be
     upgraded online. These hard limits include:

        * Database memory size and index memory size (`DataMemory' and
          `IndexMemory', respectively).

          `DataMemory' is allocated as 32KB pages. As each `DataMemory'
          page is used, it is assigned to a specific table; once
          allocated, this memory cannot be freed except by dropping the
          table.

          See *Note mysql-cluster-ndbd-definition::, for further
          information about `DataMemory' and `IndexMemory'.

        * The maximum number of operations that can be performed per
          transaction is set using the configuration parameters
          `MaxNoOfConcurrentOperations' and `MaxNoOfLocalOperations'.

          *Note*:

          Bulk loading, *Note `TRUNCATE TABLE': truncate-table, and
          *Note `ALTER TABLE': alter-table. are handled as special
          cases by running multiple transactions, and so are not subject
          to this limitation.

        * Different limits related to tables and indexes. For example,
          the maximum number of ordered indexes in the cluster is
          determined by `MaxNoOfOrderedIndexes', and the maximum number
          of ordered inexes per table is 16.

   * Memory usage

     All Cluster table rows are of fixed length. This means (for
     example) that if a table has one or more *Note `VARCHAR': char.
     fields containing only relatively small values, more memory and
     disk space is required when using the *Note `NDB': mysql-cluster.
     storage engine than would be the case for the same table and data
     using the `MyISAM' engine. (In other words, in the case of a *Note
     `VARCHAR': char. column, the column requires the same amount of
     storage as a *Note `CHAR': char. column of the same size.)

   * Node and data object maximums

     The following limits apply to numbers of cluster nodes and
     metadata objects:

        * The maximum number of data nodes is 48.

          A data node must have a node ID in the range of 1‐49,
          inclusive. (Management and API nodes may use any integer in
          the range of 1‐63 inclusive as a node ID.)

        * The total maximum number of nodes in a MySQL Cluster is 63.
          This number includes all SQL nodes (MySQL Servers), API nodes
          (applications accessing the cluster other than MySQL
          servers), data nodes, and management servers.

        * The maximum number of metadata objects in MySQL 5.0 Cluster
          is 20320. This limit is hard-coded.


File: manual.info,  Node: mysql-cluster-limitations-transactions,  Next: mysql-cluster-limitations-error-handling,  Prev: mysql-cluster-limitations-limits,  Up: mysql-cluster-limitations

17.1.5.3 Limits Relating to Transaction Handling in MySQL Cluster
.................................................................

A number of limitations exist in MySQL Cluster with regard to the
handling of transactions. These include the following:

   * Transaction isolation level

     The *Note `NDBCLUSTER': mysql-cluster. storage engine supports
     only the `READ COMMITTED' transaction isolation level.  (`InnoDB',
     for example, supports `READ COMMITTED', `READ UNCOMMITTED',
     `REPEATABLE READ', and `SERIALIZABLE'.) See *Note
     mysql-cluster-backup-troubleshooting::, for information on how
     this can affect backing up and restoring Cluster databases.)

   * Transactions and `BLOB' or `TEXT' columns

     *Note `NDBCLUSTER': mysql-cluster. stores only part of a column
     value that uses any of MySQL's *Note `BLOB': blob. or *Note
     `TEXT': blob. data types in the table visible to MySQL; the
     remainder of the *Note `BLOB': blob. or *Note `TEXT': blob. is
     stored in a separate internal table that is not accessible to
     MySQL.  This gives rise to two related issues of which you should
     be aware whenever executing *Note `SELECT': select. statements on
     tables that contain columns of these types:

       1. For any *Note `SELECT': select. from a MySQL Cluster table:
          If the *Note `SELECT': select. includes a *Note `BLOB': blob.
          or *Note `TEXT': blob. column, the `READ COMMITTED'
          transaction isolation level is converted to a read with read
          lock. This is done to guarantee consistency.

       2. For any *Note `SELECT': select. which uses a primary key
          lookup or unique key lookup to retrieve any columns that use
          any of the *Note `BLOB': blob. or *Note `TEXT': blob. data
          types and that is executed within a transaction, a shared
          read lock is held on the table for the duration of the
          transaction--that is, until the transaction is either
          committed or aborted. This does not occur for queries that
          use index or table scans.

          For example, consider the table `t' defined by the following
          *Note `CREATE TABLE': create-table. statement:

               CREATE TABLE t (
                   a INT NOT NULL AUTO_INCREMENT PRIMARY KEY,
                   b INT NOT NULL,
                   c INT NOT NULL,
                   d TEXT,
                   INDEX i(b),
                   UNIQUE KEY u(c)
               ) ENGINE = NDB,

          Either of the following queries on `t' causes a shared read
          lock, because the first query uses a primary key lookup and
          the second uses a unique key lookup:

               SELECT * FROM t WHERE a = 1;

               SELECT * FROM t WHERE c = 1;

          However, none of the four queries shown here causes a shared
          read lock:

               SELECT * FROM t WHERE b 1;

               SELECT * FROM t WHERE d = '1';

               SELECT * FROM t;

               SELECT b,c WHERE a = 1;

          This is because, of these four queries, the first uses an
          index scan, the second and third use table scans, and the
          fourth, while using a primary key lookup, does not retrieve
          the value of any *Note `BLOB': blob. or *Note `TEXT': blob.
          columns.

          You can help minimize issues with shared read locks by
          avoiding queries that use primary key lookups or unique key
          lookups to retrieve *Note `BLOB': blob. or *Note `TEXT':
          blob. columns, or, in cases where such queries are not
          avoidable, by committing transactions as soon as possible
          afterward.

          We are working on overcoming this limitation in a future
          MySQL Cluster release (see Bug #49190); however, we do not
          plan to backport any fix for this issue to MySQL 5.0.

   * Rollbacks

     There are no partial transactions, and no partial rollbacks of
     transactions. A duplicate key or similar error aborts the entire
     transaction, and subsequent statements raise `ERROR 1296 (HY000):
     Got error 4350 'Transaction already aborted' from NDBCLUSTER'. In
     such cases, you must issue an explicit *Note `ROLLBACK': commit.
     and retry the entire transaction.

     This behavior differs from that of other transactional storage
     engines such as `InnoDB' that may roll back individual statements.

   * Transactions and memory usage

     As noted elsewhere in this chapter, MySQL Cluster does not handle
     large transactions well; it is better to perform a number of small
     transactions with a few operations each than to attempt a single
     large transaction containing a great many operations. Among other
     considerations, large transactions require very large amounts of
     memory. Because of this, the transactional behavior of a number of
     MySQL statements is effected as described in the following list:

        * *Note `TRUNCATE TABLE': truncate-table. is not transactional
          when used on *Note `NDB': mysql-cluster. tables. If a *Note
          `TRUNCATE TABLE': truncate-table. fails to empty the table,
          then it must be re-run until it is successful.

        * `DELETE FROM' (even with no `WHERE' clause) _is_
          transactional. For tables containing a great many rows, you
          may find that performance is improved by using several
          `DELETE FROM ... LIMIT ...' statements to `chunk' the delete
          operation.  If your objective is to empty the table, then you
          may wish to use *Note `TRUNCATE TABLE': truncate-table.
          instead.

        * `LOAD DATA' statements

          *Note `LOAD DATA INFILE': load-data. is not transactional
          when used on *Note `NDB': mysql-cluster. tables.

          *Important*:

          When executing a *Note `LOAD DATA INFILE': load-data.
          statement, the *Note `NDB': mysql-cluster. engine performs
          commits at irregular intervals that enable better utilization
          of the communication network. It is not possible to know
          ahead of time when such commits take place.

          `LOAD DATA FROM MASTER' is not supported in MySQL Cluster.

        * `ALTER TABLE' and transactions

          When copying an *Note `NDB': mysql-cluster. table as part of
          an *Note `ALTER TABLE': alter-table, the creation of the copy
          is nontransactional. (In any case, this operation is rolled
          back when the copy is deleted.)


File: manual.info,  Node: mysql-cluster-limitations-error-handling,  Next: mysql-cluster-limitations-database-objects,  Prev: mysql-cluster-limitations-transactions,  Up: mysql-cluster-limitations

17.1.5.4 MySQL Cluster Error Handling
.....................................

Starting, stopping, or restarting a node may give rise to temporary
errors causing some transactions to fail. These include the following
cases:

   * Temporary errors

     When first starting a node, it is possible that you may see Error
     1204 `Temporary failure, distribution changed' and similar
     temporary errors.

   * Errors due to node failure

     The stopping or failure of any data node can result in a number of
     different node failure errors. (However, there should be no
     aborted transactions when performing a planned shutdown of the
     cluster.)

In either of these cases, any errors that are generated must be handled
within the application. This should be done by retrying the transaction.

See also *Note mysql-cluster-limitations-limits::.


File: manual.info,  Node: mysql-cluster-limitations-database-objects,  Next: mysql-cluster-limitations-unsupported,  Prev: mysql-cluster-limitations-error-handling,  Up: mysql-cluster-limitations

17.1.5.5 Limits Associated with Database Objects in MySQL Cluster
.................................................................

Some database objects such as tables and indexes have different
limitations when using the *Note `NDBCLUSTER': mysql-cluster. storage
engine:

   * Identifiers

     Database names, table names and attribute names cannot be as long
     in *Note `NDB': mysql-cluster. tables as when using other table
     handlers. Attribute names are truncated to 31 characters, and if
     not unique after truncation give rise to errors. Database names
     and table names can total a maximum of 122 characters. In other
     words, the maximum length for an *Note `NDB': mysql-cluster. table
     name is 122 characters, less the number of characters in the name
     of the database of which that table is a part.

   * Table names containing special characters

     *Note `NDB': mysql-cluster. tables whose names contain characters
     other than letters, numbers, dashes, and underscores and which are
     created on one SQL node may not be discovered correctly by other
     SQL nodes. (Bug #31470)

   * Number of tables and other database objects

     The maximum number of tables in a Cluster database in MySQL 5.0 is
     limited to 1792. The maximum number of _all_ *Note `NDBCLUSTER':
     mysql-cluster. database objects in a single MySQL
     Cluster--including databases, tables, and indexes--is limited to
     20320.

   * Attributes per table

     The maximum number of attributes (that is, columns and indexes)
     per table is limited to 128.

   * Attributes per key

     The maximum number of attributes per key is 32.

   * Row size

     The maximum permitted size of any one row is 8052 bytes.  Each
     *Note `BLOB': blob. or *Note `TEXT': blob. column contributes 256
     + 8 = 264 bytes to this total.


File: manual.info,  Node: mysql-cluster-limitations-unsupported,  Next: mysql-cluster-limitations-performance,  Prev: mysql-cluster-limitations-database-objects,  Up: mysql-cluster-limitations

17.1.5.6 Unsupported or Missing Features in MySQL Cluster
.........................................................

A number of features supported by other storage engines are not
supported for *Note `NDB': mysql-cluster. tables. Trying to use any of
these features in MySQL Cluster does not cause errors in or of itself;
however, errors may occur in applications that expects the features to
be supported or enforced:

   * Foreign key constraints

     The foreign key construct is ignored, just as it is in `MyISAM'
     tables.

   * Index prefixes

     Prefixes on indexes are not supported for `NDBCLUSTER' tables. If
     a prefix is used as part of an index specification in a statement
     such as *Note `CREATE TABLE': create-table, *Note `ALTER TABLE':
     alter-table, or *Note `CREATE INDEX': create-index, the prefix is
     ignored.

   * `OPTIMIZE' operations

     `OPTIMIZE' operations are not supported.

   * `LOAD TABLE ... FROM MASTER'

     `LOAD TABLE ... FROM MASTER' is not supported.

   * Savepoints and rollbacks

     Savepoints and rollbacks to savepoints are ignored as in `MyISAM'.

   * Durability of commits

     There are no durable commits on disk. Commits are replicated, but
     there is no guarantee that logs are flushed to disk on commit.

   * Replication

     Replication is not supported.

*Note*:

See *Note mysql-cluster-limitations-transactions::, for more
information relating to limitations on transaction handling in *Note
`NDB': mysql-cluster.


File: manual.info,  Node: mysql-cluster-limitations-performance,  Next: mysql-cluster-limitations-exclusive-to-cluster,  Prev: mysql-cluster-limitations-unsupported,  Up: mysql-cluster-limitations

17.1.5.7 Limitations Relating to Performance in MySQL Cluster
.............................................................

The following performance issues are specific to or especially
pronounced in MySQL Cluster:

   * Range scans

     There are query performance issues due to sequential access to the
     *Note `NDB': mysql-cluster. storage engine; it is also relatively
     more expensive to do many range scans than it is with either
     `MyISAM' or `InnoDB'.

   * Reliability of `Records in range'

     The `Records in range' statistic is available but is not
     completely tested or officially supported. This may result in
     nonoptimal query plans in some cases. If necessary, you can employ
     `USE INDEX' or `FORCE INDEX' to alter the execution plan. See
     *Note index-hints::, for more information on how to do this.

   * Unique hash indexes

     Unique hash indexes created with `USING HASH' cannot be used for
     accessing a table if `NULL' is given as part of the key.


File: manual.info,  Node: mysql-cluster-limitations-exclusive-to-cluster,  Next: mysql-cluster-limitations-multiple-nodes,  Prev: mysql-cluster-limitations-performance,  Up: mysql-cluster-limitations

17.1.5.8 Issues Exclusive to MySQL Cluster
..........................................

The following are limitations specific to the *Note `NDBCLUSTER':
mysql-cluster. storage engine:

   * Machine architecture

     The following issues relate to physical architecture of cluster
     hosts:

        * All machines used in the cluster must have the same
          architecture. That is, all machines hosting nodes must be
          either big-endian or little-endian, and you cannot use a
          mixture of both. For example, you cannot have a management
          node running on a PowerPC which directs a data node that is
          running on an x86 machine. This restriction does not apply to
          machines simply running *Note `mysql': mysql. or other
          clients that may be accessing the cluster's SQL nodes.

        * Adding and dropping of data nodes

          Online adding or dropping of data nodes is not currently
          possible. In such cases, the entire cluster must be restarted.

        * Backup and restore between architectures

          It is also not possible to perform a Cluster backup and
          restore between different architectures. For example, you
          cannot back up a cluster running on a big-endian platform and
          then restore from that backup to a cluster running on a
          little-endian system. (Bug #19255)

   * Online schema changes

     It is not possible to make online schema changes such as those
     accomplished using *Note `ALTER TABLE': alter-table. or *Note
     `CREATE INDEX': create-index, as the `NDB Cluster' engine does not
     support autodiscovery of such changes.  (However, you can import
     or create a table that uses a different storage engine, and then
     convert it to *Note `NDB': mysql-cluster. using `ALTER TABLE
     TBL_NAME ENGINE=NDBCLUSTER'. In such a case, you must issue a
     *Note `FLUSH TABLES': flush. statement to force the cluster to
     pick up the change.)

   * Binary logging

     MySQL Cluster has the following limitations or restrictions with
     regard to binary logging:

        * `sql_log_bin' has no effect on data operations; however, it
          is supported for schema operations.

        * MySQL Cluster cannot produce a binlog for tables having *Note
          `BLOB': blob. columns but no primary key.

        * Only the following schema operations are logged in a cluster
          binlog which is _not_ on the *Note `mysqld': mysqld.
          executing the statement:

             * *Note `CREATE TABLE': create-table.

             * *Note `ALTER TABLE': alter-table.

             * *Note `DROP TABLE': drop-table.

             * *Note `CREATE DATABASE': create-database. / *Note
               `CREATE SCHEMA': create-database.

             * *Note `DROP DATABASE': drop-database. / *Note `DROP
               SCHEMA': drop-database.

See also *Note mysql-cluster-limitations-multiple-nodes::.


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17.1.5.9 Limitations Relating to Multiple MySQL Cluster Nodes
.............................................................

Multiple SQL nodes

The following are issues relating to the use of multiple MySQL servers
as MySQL Cluster SQL nodes, and are specific to the *Note `NDBCLUSTER':
mysql-cluster. storage engine:

   * No distributed table locks

     A *Note `LOCK TABLES': lock-tables. works only for the SQL node on
     which the lock is issued; no other SQL node in the cluster `sees'
     this lock. This is also true for a lock issued by any statement
     that locks tables as part of its operations. (See next item for an
     example.)

   * `ALTER TABLE' operations

     *Note `ALTER TABLE': alter-table. is not fully locking when
     running multiple MySQL servers (SQL nodes).  (As discussed in the
     previous item, MySQL Cluster does not support distributed table
     locks.)

   * Replication

     MySQL replication will not work correctly if updates are done on
     multiple MySQL servers. However, if the database partitioning
     scheme is done at the application level and no transactions take
     place across these partitions, replication can be made to work.

   * Database autodiscovery

     Autodiscovery of databases is not supported for multiple MySQL
     servers accessing the same MySQL Cluster. However, autodiscovery
     of tables is supported in such cases. What this means is that
     after a database named DB_NAME is created or imported using one
     MySQL server, you should issue a `CREATE DATABASE DB_NAME'
     statement on each additional MySQL server that accesses the same
     MySQL Cluster. (As of MySQL 5.0.2, you may also use `CREATE SCHEMA
     DB_NAME'.) Once this has been done for a given MySQL server, that
     server should be able to detect the database tables without error.

   * DDL operations

     DDL operations (such as *Note `CREATE TABLE': create-table. or
     *Note `ALTER TABLE': alter-table.) are not safe from data node
     failures. If a data node fails while trying to perform one of
     these, the data dictionary is locked and no further DDL statements
     can be executed without restarting the cluster.

Multiple management nodes

When using multiple management servers:

   * You must give nodes explicit IDs in connectstrings because
     automatic allocation of node IDs does not work across multiple
     management servers.

     In addition, all API nodes (including MySQL servers acting as SQL
     nodes), should list all management servers using the same order in
     their connectstrings.

   * You must take extreme care to have the same configurations for all
     management servers. No special checks for this are performed by
     the cluster.

   * Prior to MySQL 5.0.14, all data nodes had to be restarted after
     bringing up the cluster for the management nodes to be able to see
     one another.

     (See Bug #12307 and Bug #13070 for more information.)

Multiple data node processes

While it is possible to run multiple cluster processes concurrently on
a single host, it is not always advisable to do so for reasons of
performance and high availability, as well as other considerations. In
particular, in MySQL 5.0, we do not support for production use any
MySQL Cluster deployment in which more than one *Note `ndbd':
mysql-cluster-programs-ndbd. process is run on a single physical
machine.

*Note*:

We may support multiple data nodes per host in a future MySQL release,
following additional testing. However, in MySQL 5.0, such
configurations can be considered experimental only.

Multiple network addresses

Multiple network addresses per data node are not supported.  Use of
these is liable to cause problems: In the event of a data node failure,
an SQL node waits for confirmation that the data node went down but
never receives it because another route to that data node remains open.
This can effectively make the cluster inoperable.

*Note*:

It is possible to use multiple network hardware _interfaces_ (such as
Ethernet cards) for a single data node, but these must be bound to the
same address.  This also means that it not possible to use more than one
`[tcp]' section per connection in the `config.ini' file. See *Note
mysql-cluster-tcp-definition::, for more information.


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17.1.5.10 Previous MySQL Cluster Issues Resolved in MySQL 5.0
.............................................................

The following Cluster limitations in MySQL 4.1 have been resolved in
MySQL 5.0 as shown below:

   * Character set support

     The *Note `NDBCLUSTER': mysql-cluster. storage engine supports all
     character sets and collations available in MySQL 5.0.

   * Character set directory

     Beginning with MySQL 5.0.21, it is possible to install MySQL with
     Cluster support to a nondefault location and change the search
     path for font description files using either the `--basedir' or
     `--character-sets-dir' options. (Previously, *Note `ndbd':
     mysql-cluster-programs-ndbd. in MySQL 5.0 searched only the
     default path--typically
     `/usr/local/mysql/share/mysql/charsets'--for character sets.)

   * Metadata objects

     Prior to MySQL 5.0.6, the maximum number of metadata objects
     possible was 1600. Beginning with MySQL 5.0.6, this limit is
     increased to 20320.

   * Query cache

     Unlike the case in MySQL 4.1, the Cluster storage engine in MySQL
     5.0 supports MySQL's query cache. See *Note query-cache::.

   * `IGNORE' and `REPLACE' functionality

     In MySQL 5.0.19 and earlier, *Note `INSERT IGNORE': insert,
     `UPDATE IGNORE', and *Note `REPLACE': replace. were supported only
     for primary keys, but not for unique keys. It was possible to work
     around this issue by removing the constraint, then dropping the
     unique index, performing any inserts, and then adding the unique
     index again.

     This limitation was removed for *Note `INSERT IGNORE': insert. and
     *Note `REPLACE': replace.  in MySQL 5.0.20. (See Bug #17431.)

   * `auto_increment_increment' and `auto_increment_offset'

     The `auto_increment_increment' and `auto_increment_offset' server
     system variables are supported for *Note `NDBCLUSTER':
     mysql-cluster. tables beginning with MySQL 5.0.46.


File: manual.info,  Node: mysql-cluster-installation,  Next: mysql-cluster-configuration,  Prev: mysql-cluster-overview,  Up: mysql-cluster

17.2 MySQL Cluster Installation
===============================

* Menu:

* mysql-cluster-install-linux::  Installing MySQL Cluster on Linux
* mysql-cluster-install-configuration::  Initial Configuration of MySQL Cluster
* mysql-cluster-install-first-start::  Initial Startup of MySQL Cluster
* mysql-cluster-install-example-data::  MySQL Cluster Example with Tables and Data
* mysql-cluster-install-shutdown-restart::  Safe Shutdown and Restart of MySQL Cluster
* mysql-cluster-upgrade-downgrade::  Upgrading and Downgrading MySQL Cluster

This section describes the basics for planning, installing,
configuring, and running a MySQL Cluster. Whereas the examples in *Note
mysql-cluster-configuration:: provide more in-depth information on a
variety of clustering options and configuration, the result of
following the guidelines and procedures outlined here should be a
usable MySQL Cluster which meets the _minimum_ requirements for
availability and safeguarding of data.

This section covers hardware and software requirements; networking
issues; installation of MySQL Cluster; configuration issues; starting,
stopping, and restarting the cluster; loading of a sample database; and
performing queries.

Assumptions

The following sections make a number of assumptions regarding the
cluster's physical and network configuration. These assumptions are
discussed in the next few paragraphs.

Cluster nodes and host computers

The cluster consists of four nodes, each on a separate host computer,
and each with a fixed network address on a typical Ethernet network as
shown here:

Node                                 IP Address
Management node (`mgmd')             192.168.0.10
SQL node (*Note `mysqld': mysqld.)   192.168.0.20
Data node "A" (*Note `ndbd':         192.168.0.30
mysql-cluster-programs-ndbd.)        
Data node "B" (*Note `ndbd':         192.168.0.40
mysql-cluster-programs-ndbd.)        

This may be made clearer by the following diagram:

MySQL Cluster Multi-Computer Setup

Network addressing

In the interest of simplicity (and reliability), this `How-To' uses
only numeric IP addresses.  However, if DNS resolution is available on
your network, it is possible to use host names in lieu of IP addresses
in configuring Cluster. Alternatively, you can use the `hosts' file
(typically `/etc/hosts' for Linux and other Unix-like operating
systems, or your operating system's equivalent) for providing a means
to do host lookup if such is available.

Potential hosts file issues

A common problem when trying to use host names for Cluster nodes arises
because of the way in which some operating systems (including some
Linux distributions) set up the system's own host name in the
`/etc/hosts' during installation. Consider two machines with the host
names `ndb1' and `ndb2', both in the `cluster' network domain. Red Hat
Linux (including some derivatives such as CentOS and Fedora) places the
following entries in these machines' `/etc/hosts' files:

     #  ndb1 `/etc/hosts':
     127.0.0.1   ndb1.cluster ndb1 localhost.localdomain localhost

     #  ndb2 `/etc/hosts':
     127.0.0.1   ndb2.cluster ndb2 localhost.localdomain localhost

SUSE Linux (including OpenSUSE) places these entries in the machines'
`/etc/hosts' files:

     #  ndb1 `/etc/hosts':
     127.0.0.1       localhost
     127.0.0.2       ndb1.cluster ndb1

     #  ndb2 `/etc/hosts':
     127.0.0.1       localhost
     127.0.0.2       ndb2.cluster ndb2

In both instances, `ndb1' routes `ndb1.cluster' to a loopback IP
address, but gets a public IP address from DNS for `ndb2.cluster',
while `ndb2' routes `ndb2.cluster' to a loopback address and obtains a
public address for `ndb1.cluster'. The result is that each data node
connects to the management server, but cannot tell when any other data
nodes have connected, and so the data nodes appear to hang while
starting.

*Caution*:

You cannot mix `localhost' and other host names or IP addresses in
`config.ini'. For these reasons, the solution in such cases (other than
to use IP addresses for _all_ `config.ini' `HostName' entries) is to
remove the fully qualified host names from `/etc/hosts' and use these in
`config.ini' for all cluster hosts.

Host computer type

Each host computer in our installation scenario is an Intel-based
desktop PC running a supported operating system installed to disk in a
standard configuration, and running no unnecessary services.  The core
operating system with standard TCP/IP networking capabilities should be
sufficient. Also for the sake of simplicity, we also assume that the
file systems on all hosts are set up identically. In the event that
they are not, you should adapt these instructions accordingly.

Network hardware

Standard 100 Mbps or 1 gigabit Ethernet cards are installed on each
machine, along with the proper drivers for the cards, and that all four
hosts are connected through a standard-issue Ethernet networking
appliance such as a switch. (All machines should use network cards with
the same throughout. That is, all four machines in the cluster should
have 100 Mbps cards _or_ all four machines should have 1 Gbps cards.)
MySQL Cluster works in a 100 Mbps network; however, gigabit Ethernet
provides better performance.

*Important*:

MySQL Cluster is _not_ intended for use in a network for which
throughput is less than 100 Mbps or which experiences a high degree of
latency. For this reason (among others), attempting to run a MySQL
Cluster over a wide area network such as the Internet is not likely to
be successful, and is not supported in production.

Sample data

We use the `world' database which is available for download from the
MySQL Web site (see `http://dev.mysql.com/doc/index-other.html'). We
assume that each machine has sufficient memory for running the operating
system, required MySQL Cluster processes, and (on the data nodes)
storing the database.

For general information about installing MySQL, see *Note installing::.
For information about installation of MySQL Cluster on Linux and other
Unix-like operating systems, see *Note mysql-cluster-install-linux::.

For general information about MySQL Cluster hardware, software, and
networking requirements, see *Note
mysql-cluster-overview-requirements::.


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17.2.1 Installing MySQL Cluster on Linux
----------------------------------------

* Menu:

* mysql-cluster-install-linux-binary::  Installing a MySQL Cluster Binary Release on Linux
* mysql-cluster-install-linux-rpm::  Installing MySQL Cluster from RPM
* mysql-cluster-install-linux-source::  Building MySQL Cluster from Source on Linux

This section covers installation of MySQL Cluster on Linux and other
Unix-like operating systems. While the next few sections refer to a
Linux operating system, the instructions and procedures given there
should be easily adaptable to other supported Unix-like platforms.

Each MySQL Cluster host computer must have the correct executable
programs installed. A host running an SQL node must have installed on
it a MySQL Server binary (*Note `mysqld': mysqld.).  Management nodes
require the management server daemon (*Note `ndb_mgmd':
mysql-cluster-programs-ndb-mgmd.); data nodes require the data node
daemon (*Note `ndbd': mysql-cluster-programs-ndbd. It is not necessary
to install the MySQL Server binary on management node hosts and data
node hosts. It is recommended that you also install the management
client (*Note `ndb_mgm': mysql-cluster-programs-ndb-mgm.) on the
management server host.

Installation of MySQL Cluster on Linux can be done using precompiled
binaries from Oracle (downloaded as a .tar.gz archive), with RPM
packages (also available from Oracle), or from source code. All three
of these installation methods are described in the section that follow.

Regardless of the method used, it is still necessary following
installation of the MySQL Cluster binaries to create configuration
files for all cluster nodes, before you can start the cluster. See
*Note mysql-cluster-install-configuration::.


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17.2.1.1 Installing a MySQL Cluster Binary Release on Linux
...........................................................

This section covers the steps necessary to install the correct
executables for each type of Cluster node from precompiled binaries
supplied by Oracle.

For setting up a cluster using precompiled binaries, the first step in
the installation process for each cluster host is to download the
latest MySQL 5.0 binary archive from the MySQL downloads page. We
assume that you have placed this file in each machine's `/var/tmp'
directory.  (If you do require a custom binary, see *Note
installing-development-tree::.)

*Note*:

After completing the installation, do not yet start any of the
binaries. We show you how to do so following the configuration of the
nodes (see *Note mysql-cluster-install-configuration::).

Data nodes and SQL nodes

On each of the machines designated to host data nodes or SQL nodes,
perform the following steps as the system `root' user:

  1. Check your `/etc/passwd' and `/etc/group' files (or use whatever
     tools are provided by your operating system for managing users and
     groups) to see whether there is already a `mysql' group and `mysql'
     user on the system. Some OS distributions create these as part of
     the operating system installation process. If they are not already
     present, create a new `mysql' user group, and then add a `mysql'
     user to this group:

          shell> groupadd mysql
          shell> useradd -g mysql mysql

     The syntax for `useradd' and `groupadd' may differ slightly on
     different versions of Unix, or they may have different names such
     as `adduser' and `addgroup'.

  2. Change location to the directory containing the downloaded file,
     unpack the archive, and create a symbolic link named `mysql' to
     the `mysql' directory. Note that the actual file and directory
     names vary according to the MySQL Cluster version number.

          shell> cd /var/tmp
          shell> tar -C /usr/local -xzvf mysql-cluster-gpl-7.1.19-linux-i686-glibc23.tar.gz
          shell> ln -s /usr/local/mysql-cluster-gpl-7.1.19-linux-i686-glibc23 /usr/local/mysql

  3. Change location to the `mysql' directory and run the supplied
     script for creating the system databases:

          shell> cd mysql
          shell> scripts/mysql_install_db --user=mysql

  4. Set the necessary permissions for the MySQL server and data
     directories:

          shell> chown -R root .
          shell> chown -R mysql data
          shell> chgrp -R mysql .

     Note that the data directory on each machine hosting a data node
     is `/usr/local/mysql/data'. This piece of information is essential
     when configuring the management node. (See *Note
     mysql-cluster-install-configuration::.)

  5. Copy the MySQL startup script to the appropriate directory, make
     it executable, and set it to start when the operating system is
     booted up:

          shell> cp support-files/mysql.server /etc/rc.d/init.d/
          shell> chmod +x /etc/rc.d/init.d/mysql.server
          shell> chkconfig --add mysql.server

     (The startup scripts directory may vary depending on your
     operating system and version--for example, in some Linux
     distributions, it is `/etc/init.d'.)

     Here we use Red Hat's `chkconfig' for creating links to the
     startup scripts; use whatever means is appropriate for this
     purpose on your operating system and distribution, such as
     `update-rc.d' on Debian.

Remember that the preceding steps must be repeated on each machine
where an SQL node is to reside.

Management nodes

Installation of the management node does not require the *Note
`mysqld': mysqld. binary. Only the MySQL Cluster management server
(*Note `ndb_mgmd': mysql-cluster-programs-ndb-mgmd.) is required; you
most likely want to install the management client (*Note `ndb_mgm':
mysql-cluster-programs-ndb-mgm.) as well. Both of these binaries also
be found in the `.tar.gz' archive.  Again, we assume that you have
placed this archive in `/var/tmp'.

As system `root' (that is, after using `sudo', `su root', or your
system's equivalent for temporarily assuming the system administrator
account's privileges), perform the following steps to install *Note
`ndb_mgmd': mysql-cluster-programs-ndb-mgmd. and *Note `ndb_mgm':
mysql-cluster-programs-ndb-mgm. on the Cluster management node host:

  1. Change location to the `/var/tmp' directory, and extract the *Note
     `ndb_mgm': mysql-cluster-programs-ndb-mgm. and *Note `ndb_mgmd':
     mysql-cluster-programs-ndb-mgmd. from the archive into a suitable
     directory such as `/usr/local/bin':

          shell> cd /var/tmp
          shell> tar -zxvf mysql-5.1.56-ndb-7.1.19-linux-i686-glibc23.tar.gz
          shell> cd mysql-5.1.56-ndb-7.1.19-linux-i686-glibc23
          shell> cp bin/ndb_mgm* /usr/local/bin

     (You can safely delete the directory created by unpacking the
     downloaded archive, and the files it contains, from `/var/tmp' once
     *Note `ndb_mgm': mysql-cluster-programs-ndb-mgm. and *Note
     `ndb_mgmd': mysql-cluster-programs-ndb-mgmd.  have been copied to
     the executables directory.)

  2. Change location to the directory into which you copied the files,
     and then make both of them executable:

          shell> cd /usr/local/bin
          shell> chmod +x ndb_mgm*

In *Note mysql-cluster-install-configuration::, we create configuration
files for all of the nodes in our example MySQL Cluster.


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17.2.1.2 Installing MySQL Cluster from RPM
..........................................

This section covers the steps necessary to install the correct
executables for each type of MySQL Cluster node using RPM packages
supplied by Oracle.

RPMs are available for both 32-bit and 64-bit Linux platforms.  For a
MySQL Cluster, three RPMs are required:

   * The *Server* RPM (for example,
     `MySQL-server-5.0.95-0.glibc23.i386.rpm'), which supplies the core
     files needed to run a MySQL Server.

     If you do not have your own client application capable of
     administering a MySQL server, you should also obtain and install
     the *Client* RPM (such as `MySQL-client-5.0.95-0.sles10.i586.rpm').

   * The *NDB Cluster - Storage engine* RPM (for example,
     `MySQL-ndb-storage-5.0.95-0.glibc23.i386.rpm'), which supplies the
     MySQL Cluster data node binary (*Note `ndbd':
     mysql-cluster-programs-ndbd.).

   * The *NDB Cluster - Storage engine management RPM* (for example,
     `MySQL-ndb-management-5.0.95-0.glibc23.i386.rpm'), which provides
     the MySQL Cluster management server binary (*Note `ndb_mgmd':
     mysql-cluster-programs-ndb-mgmd.).

In addition, you should also obtain the *NDB Cluster - Storage engine
basic tools* RPM (for example,
`MySQL-ndb-tools-5.0.95-0.glibc23.i386.rpm'), which supplies several
useful applications for working with a MySQL Cluster. The most
important of these is the MySQL Cluster management client (*Note
`ndb_mgm': mysql-cluster-programs-ndb-mgm.). The *NDB Cluster - Storage
engine extra tools* RPM (for example,
`MySQL-ndb-extra-5.0.95-0.glibc23.i386.rpm') contains some additional
testing and monitoring programs, but is not required to install a MySQL
Cluster. (For more information about these additional programs, see
*Note mysql-cluster-programs::.)

The MySQL version number in the RPM file names (shown here as `5.0.95')
can vary according to the version which you are actually using. _It is
very important that all of the Cluster RPMs to be installed have the
same MySQL version number_. The `glibc' version number (if
present--shown here as `glibc23'), and architecture designation (shown
here as `i386') should be appropriate to the machine on which the RPM
is to be installed.

Data nodes

On a computer that is to host a cluster data node it is necessary to
install only the *NDB Cluster - Storage engine* RPM. To do so, copy this
RPM to the data node host, and run the following command as the system
root user, replacing the name shown for the RPM as necessary to match
that of the RPM downloaded from the MySQL web site:

     shell> rpm -Uhv MySQL-ndb-storage-5.0.95-0.glibc23.i386.rpm

The previous command installs the MySQL Cluster data node binary (*Note
`ndbd': mysql-cluster-programs-ndbd.) in the `/usr/sbin' directory.

SQL nodes

On each machine to be used for hosting a cluster SQL node, install the
*Server* RPM by executing the following command as the system root user,
replacing the name shown for the RPM as necessary to match the name of
the RPM downloaded from the MySQL web site:

     shell> rpm -Uhv MySQL-server-5.0.95-0.glibc23.i386.rpm

This installs the MySQL server binary (*Note `mysqld': mysqld.) in the
`/usr/sbin' directory, as well as all needed MySQL Server support
files. It also installs the *Note `mysql.server': mysql-server. and
*Note `mysqld_safe': mysqld-safe. startup scripts in `/usr/share/mysql'
and `/usr/bin', respectively. The RPM installer should take care of
general configuration issues (such as creating the `mysql' user and
group, if needed) automatically.

*Note*:

To administer the SQL node (MySQL server), you should also install the
*Client* RPM, as shown here:

     shell> rpm -Uhv MySQL-client-5.0.95-0.sles10.i586.rpm

This installs the *Note `mysql': mysql. client program.

Management nodes

To install the MySQL Cluster management server, it is necessary only to
use the *NDB Cluster - Storage engine management* RPM. Copy this RPM to
the computer intended to host the management node, and then install it
by running the following command as the system root user (replace the
name shown for the RPM as necessary to match that of the *Storage engine
management* RPM downloaded from the MySQL web site):

     shell> rpm -Uhv MySQL-ndb-management-5.0.95-0.glibc23.i386.rpm

This installs the management server binary (*Note `ndb_mgmd':
mysql-cluster-programs-ndb-mgmd.) to the `/usr/sbin' directory.

You should also install the *Note `NDB': mysql-cluster.  management
client, which is supplied by the *Storage engine basic tools* RPM.
Copy this RPM to the same computer as the management node, and then
install it by running the following command as the system root user
(again, replace the name shown for the RPM as necessary to match that
of the *Storage engine basic tools* RPM downloaded from the MySQL web
site):

     shell> rpm -Uhv MySQL-ndb-tools-5.0.95-0.sles10.i586.rpm

The *Storage engine basic tools* RPM installs the MySQL Cluster
management client (*Note `ndb_mgm': mysql-cluster-programs-ndb-mgm.) to
the `/usr/bin' directory.

*Note*:

You can also install the *Cluster storage engine extra tools* RPM, if
you wish, as shown here:

     shell> rpm -Uhv MySQL-ndb-extra-5.0.95-0.sles10.i586.rpm

You may find the extra tools useful; however the *Cluster storage
engine extra tools* RPM is _not_ required to install a working MySQL
Cluster.

See *Note linux-installation-rpm::, for general information about
installing MySQL using RPMs supplied by Oracle.

After installing from RPM, you still need to configure the cluster as
discussed in *Note mysql-cluster-install-configuration::.


File: manual.info,  Node: mysql-cluster-install-linux-source,  Prev: mysql-cluster-install-linux-rpm,  Up: mysql-cluster-install-linux

17.2.1.3 Building MySQL Cluster from Source on Linux
....................................................

This section provides information about compiling MySQL Cluster on
Linux and other Unix-like platforms.To build MySQL Cluster, you need
the MySQL 5.0 source archive available from
http://dev.mysql.com/downloads/. Building MySQL Cluster from source is
similar to building the standard MySQL Server, although it differs in a
few key respects discussed here. For general information about building
MySQL from source, see *Note source-installation::.

In addition to any other `configure' options you wish to use, be sure
to include `--with-ndbcluster'. This option causes the binaries for the
management nodes, data nodes, and other MySQL Cluster programs to be
built; it also causes *Note `mysqld': mysqld. to be compiled with *Note
`NDB': mysql-cluster. storage engine support.

After you have run `make && make install' (or your system's
equivalent), the result is similar to what is obtained by unpacking a
precompiled binary to the same location. However, the layout can
differ. These differences are covered in the next few paragraphs.

Management nodes

When building from source and running the default `make install', the
management server binary (*Note `ndb_mgmd':
mysql-cluster-programs-ndb-mgmd.) is placed in
`/usr/local/mysql/libexec', while the management client binary (*Note
`ndb_mgm': mysql-cluster-programs-ndb-mgm.) can be found in
`/usr/local/mysql/bin'. Only *Note `ndb_mgmd':
mysql-cluster-programs-ndb-mgmd. is required to be present on a
management node host; however, it is also a good idea to have *Note
`ndb_mgm': mysql-cluster-programs-ndb-mgm. present on the same host
machine.  Neither of these executables requires a specific location on
the host machine's file system.

Data nodes

The only executable required on a data node host is *Note `ndbd':
mysql-cluster-programs-ndbd. (*Note `mysqld': mysqld, for example, does
not have to be present on the host machine). By default when doing a
source build, this file is placed in the directory
`/usr/local/mysql/libexec'. For installing on multiple data node hosts,
only *Note `ndbd': mysql-cluster-programs-ndbd. need be copied to the
other host machine or machines. (This assumes that all data node hosts
use the same architecture and operating system; otherwise you may need
to compile separately for each different platform.)  *Note `ndbd':
mysql-cluster-programs-ndbd. need not be in any particular location on
the host's file system, as long as the location is known.

SQL nodes

If you compile MySQL with clustering support, and perform the default
installation (using `make install' as the system `root' user), *Note
`mysqld': mysqld. is placed in `/usr/local/mysql/bin'. Follow the steps
given in *Note source-installation:: to make *Note `mysqld': mysqld.
ready for use. If you want to run multiple SQL nodes, you can use a
copy of the same *Note `mysqld': mysqld. executable and its associated
support files on several machines. The easiest way to do this is to
copy the entire `/usr/local/mysql' directory and all directories and
files contained within it to the other SQL node host or hosts, then
repeat the steps from *Note source-installation:: on each machine. If
you configure the build with a nondefault `--prefix', you need to adjust
the directory accordingly.

In *Note mysql-cluster-install-configuration::, we create configuration
files for all of the nodes in our example MySQL Cluster.


File: manual.info,  Node: mysql-cluster-install-configuration,  Next: mysql-cluster-install-first-start,  Prev: mysql-cluster-install-linux,  Up: mysql-cluster-installation

17.2.2 Initial Configuration of MySQL Cluster
---------------------------------------------

For our four-node, four-host MySQL Cluster, it is necessary to write
four configuration files, one per node host.

   * Each data node or SQL node requires a `my.cnf' file that provides
     two pieces of information: a _connectstring_ that tells the node
     where to find the management node, and a line telling the MySQL
     server on this host (the machine hosting the data node) to enable
     the *Note `NDBCLUSTER': mysql-cluster.  storage engine.

     For more information on connectstrings, see *Note
     mysql-cluster-connectstring::.

   * The management node needs a `config.ini' file telling it how many
     replicas to maintain, how much memory to allocate for data and
     indexes on each data node, where to find the data nodes, where to
     save data to disk on each data node, and where to find any SQL
     nodes.

Configuring the data nodes and SQL nodes

The `my.cnf' file needed for the data nodes is fairly simple. The
configuration file should be located in the `/etc' directory and can be
edited using any text editor. (Create the file if it does not exist.)
For example:

     shell> vi /etc/my.cnf

*Note*:

We show `vi' being used here to create the file, but any text editor
should work just as well.

For each data node and SQL node in our example setup, `my.cnf' should
look like this:

     [mysqld]
     # Options for mysqld process:
     ndbcluster                      # run NDB storage engine
     ndb-connectstring=192.168.0.10  # location of management server

     [mysql_cluster]
     # Options for ndbd process:
     ndb-connectstring=192.168.0.10  # location of management server

After entering the preceding information, save this file and exit the
text editor. Do this for the machines hosting data node `A', data node
`B', and the SQL node.

*Important*:

Once you have started a *Note `mysqld': mysqld. process with the *Note
`NDBCLUSTER': mysql-cluster. and `ndb-connectstring' parameters in the
`[mysqld]' in the `my.cnf' file as shown previously, you cannot execute
any *Note `CREATE TABLE': create-table. or *Note `ALTER TABLE':
alter-table. statements without having actually started the cluster.
Otherwise, these statements will fail with an error. _This is by
design_.

Configuring the management node

The first step in configuring the management node is to create the
directory in which the configuration file can be found and then to
create the file itself. For example (running as `root'):

     shell> mkdir /var/lib/mysql-cluster
     shell> cd /var/lib/mysql-cluster
     shell> vi config.ini

For our representative setup, the `config.ini' file should read as
follows:

     [ndbd default]
     # Options affecting ndbd processes on all data nodes:
     NoOfReplicas=2    # Number of replicas
     DataMemory=80M    # How much memory to allocate for data storage
     IndexMemory=18M   # How much memory to allocate for index storage
                       # For DataMemory and IndexMemory, we have used the
                       # default values. Since the "world" database takes up
                       # only about 500KB, this should be more than enough for
                       # this example Cluster setup.

     [tcp default]
     # TCP/IP options:
     portnumber=2202   # This the default; however, you can use any
                       # port that is free for all the hosts in the cluster
                       # Note: It is recommended that you do not specify the port
                       # number at all and simply allow the default value to be used
                       # instead

     [ndb_mgmd]
     # Management process options:
     hostname=192.168.0.10           # Hostname or IP address of MGM node
     datadir=/var/lib/mysql-cluster  # Directory for MGM node log files

     [ndbd]
     # Options for data node "A":
                                     # (one [ndbd] section per data node)
     hostname=192.168.0.30           # Hostname or IP address
     datadir=/usr/local/mysql/data   # Directory for this data node's data files

     [ndbd]
     # Options for data node "B":
     hostname=192.168.0.40           # Hostname or IP address
     datadir=/usr/local/mysql/data   # Directory for this data node's data files

     [mysqld]
     # SQL node options:
     hostname=192.168.0.20           # Hostname or IP address
                                     # (additional mysqld connections can be
                                     # specified for this node for various
                                     # purposes such as running ndb_restore)

*Note*:

The `world' database can be downloaded from
`http://dev.mysql.com/doc/', where it can be found listed under
`Examples'.

After all the configuration files have been created and these minimal
options have been specified, you are ready to proceed with starting the
cluster and verifying that all processes are running.  We discuss how
this is done in *Note mysql-cluster-install-first-start::.

For more detailed information about the available MySQL Cluster
configuration parameters and their uses, see *Note
mysql-cluster-config-file::, and *Note mysql-cluster-configuration::.
For configuration of MySQL Cluster as relates to making backups, see
*Note mysql-cluster-backup-configuration::.

*Note*:

The default port for Cluster management nodes is 1186; the default port
for data nodes is 2202. Beginning with MySQL 5.0.3, this restriction is
lifted, and the cluster automatically allocates ports for data nodes
from those that are already free.


File: manual.info,  Node: mysql-cluster-install-first-start,  Next: mysql-cluster-install-example-data,  Prev: mysql-cluster-install-configuration,  Up: mysql-cluster-installation

17.2.3 Initial Startup of MySQL Cluster
---------------------------------------

Starting the cluster is not very difficult after it has been
configured. Each cluster node process must be started separately, and
on the host where it resides. The management node should be started
first, followed by the data nodes, and then finally by any SQL nodes:

  1. On the management host, issue the following command from the
     system shell to start the management node process:

          shell> ndb_mgmd -f /var/lib/mysql-cluster/config.ini

     *Note*:

     *Note `ndb_mgmd': mysql-cluster-programs-ndb-mgmd. must be told
     where to find its configuration file, using the `-f' or
     `--config-file' option. (See *Note
     mysql-cluster-programs-ndb-mgmd::, for details.)

     For additional options which can be used with *Note `ndb_mgmd':
     mysql-cluster-programs-ndb-mgmd, see *Note
     mysql-cluster-program-options-common::.

  2. On each of the data node hosts, run this command to start the
     *Note `ndbd': mysql-cluster-programs-ndbd. process:

          shell> ndbd

  3. If you used RPM files to install MySQL on the cluster host where
     the SQL node is to reside, you can (and should) use the supplied
     startup script to start the MySQL server process on the SQL node.

If all has gone well, and the cluster has been set up correctly, the
cluster should now be operational. You can test this by invoking the
*Note `ndb_mgm': mysql-cluster-programs-ndb-mgm. management node client.
The output should look like that shown here, although you might see
some slight differences in the output depending upon the exact version
of MySQL that you are using:

     shell> ndb_mgm
     -- NDB Cluster -- Management Client --
     ndb_mgm> SHOW
     Connected to Management Server at: localhost:1186
     Cluster Configuration
     ---------------------
     [ndbd(NDB)]     2 node(s)
     id=2    @192.168.0.30  (Version: 5.0.95, Nodegroup: 0, Master)
     id=3    @192.168.0.40  (Version: 5.0.95, Nodegroup: 0)

     [ndb_mgmd(MGM)] 1 node(s)
     id=1    @192.168.0.10  (Version: 5.0.95)

     [mysqld(API)]   1 node(s)
     id=4    @192.168.0.20  (Version: 5.0.95)

The SQL node is referenced here as `[mysqld(API)]', which reflects the
fact that the *Note `mysqld': mysqld. process is acting as a MySQL
Cluster API node.

*Note*:

The IP address shown for a given MySQL Cluster SQL or other API node in
the output of `SHOW' is the address used by the SQL or API node to
connect to the cluster data nodes, and not to any management node.

You should now be ready to work with databases, tables, and data in
MySQL Cluster. See *Note mysql-cluster-install-example-data::, for a
brief discussion.


File: manual.info,  Node: mysql-cluster-install-example-data,  Next: mysql-cluster-install-shutdown-restart,  Prev: mysql-cluster-install-first-start,  Up: mysql-cluster-installation

17.2.4 MySQL Cluster Example with Tables and Data
-------------------------------------------------

Working with database tables and data in MySQL Cluster is not much
different from doing so in standard MySQL. There are two key points to
keep in mind:

   * For a table to be replicated in the cluster, it must use the *Note
     `NDBCLUSTER': mysql-cluster. storage engine. To specify this, use
     the `ENGINE=NDBCLUSTER' or `ENGINE=NDB' option when creating the
     table:

          CREATE TABLE TBL_NAME (COL_NAME COLUMN_DEFINITIONS) ENGINE=NDBCLUSTER;

     Alternatively, for an existing table that uses a different storage
     engine, use *Note `ALTER TABLE': alter-table.  to change the table
     to use *Note `NDBCLUSTER': mysql-cluster.:

          ALTER TABLE TBL_NAME ENGINE=NDBCLUSTER;

   * Every *Note `NDBCLUSTER': mysql-cluster. table has a primary key.
     If no primary key is defined by the user when a table is created,
     the *Note `NDBCLUSTER': mysql-cluster.  storage engine
     automatically generates a hidden one. Such a key takes up space
     just as does any other table index. (It is not uncommon to
     encounter problems due to insufficient memory for accommodating
     these automatically created indexes.)

If you are importing tables from an existing database using the output
of *Note `mysqldump': mysqldump, you can open the SQL script in a text
editor and add the `ENGINE' option to any table creation statements, or
replace any existing `ENGINE' (or `TYPE') options.  Suppose that you
have the `world' sample database on another MySQL server that does not
support MySQL Cluster, and you want to export the `City' table:

     shell> mysqldump --add-drop-table world City > city_table.sql

The resulting `city_table.sql' file will contain this table creation
statement (and the *Note `INSERT': insert. statements necessary to
import the table data):

     DROP TABLE IF EXISTS `City`;
     CREATE TABLE `City` (
       `ID` int(11) NOT NULL auto_increment,
       `Name` char(35) NOT NULL default '',
       `CountryCode` char(3) NOT NULL default '',
       `District` char(20) NOT NULL default '',
       `Population` int(11) NOT NULL default '0',
       PRIMARY KEY  (`ID`)
     ) ENGINE=MyISAM DEFAULT CHARSET=latin1;

     INSERT INTO `City` VALUES (1,'Kabul','AFG','Kabol',1780000);
     INSERT INTO `City` VALUES (2,'Qandahar','AFG','Qandahar',237500);
     INSERT INTO `City` VALUES (3,'Herat','AFG','Herat',186800);(REMAINING INSERT STATEMENTS OMITTED)

You need to make sure that MySQL uses the *Note `NDBCLUSTER':
mysql-cluster. storage engine for this table. There are two ways that
this can be accomplished. One of these is to modify the table definition
_before_ importing it into the Cluster database. Using the `City' table
as an example, modify the `ENGINE' option of the definition as follows:

     DROP TABLE IF EXISTS `City`;
     CREATE TABLE `City` (
       `ID` int(11) NOT NULL auto_increment,
       `Name` char(35) NOT NULL default '',
       `CountryCode` char(3) NOT NULL default '',
       `District` char(20) NOT NULL default '',
       `Population` int(11) NOT NULL default '0',
       PRIMARY KEY  (`ID`)
     ) *ENGINE=NDBCLUSTER* DEFAULT CHARSET=latin1;

     INSERT INTO `City` VALUES (1,'Kabul','AFG','Kabol',1780000);
     INSERT INTO `City` VALUES (2,'Qandahar','AFG','Qandahar',237500);
     INSERT INTO `City` VALUES (3,'Herat','AFG','Herat',186800);
     (REMAINING INSERT STATEMENTS OMITTED)

This must be done for the definition of each table that is to be part
of the clustered database. The easiest way to accomplish this is to do
a search-and-replace on the file that contains the definitions and
replace all instances of `TYPE=ENGINE_NAME' or `ENGINE=ENGINE_NAME'
with `ENGINE=NDBCLUSTER'. If you do not want to modify the file, you
can use the unmodified file to create the tables, and then use *Note
`ALTER TABLE': alter-table. to change their storage engine. The
particulars are given later in this section.

Assuming that you have already created a database named `world' on the
SQL node of the cluster, you can then use the *Note `mysql': mysql.
command-line client to read `city_table.sql', and create and populate
the corresponding table in the usual manner:

     shell> mysql world < city_table.sql

It is very important to keep in mind that the preceding command must be
executed on the host where the SQL node is running (in this case, on
the machine with the IP address `192.168.0.20').

To create a copy of the entire `world' database on the SQL node, use
*Note `mysqldump': mysqldump. on the noncluster server to export the
database to a file named `world.sql'; for example, in the `/tmp'
directory. Then modify the table definitions as just described and
import the file into the SQL node of the cluster like this:

     shell> mysql world < /tmp/world.sql

If you save the file to a different location, adjust the preceding
instructions accordingly.

*Note*:

*Note `NDBCLUSTER': mysql-cluster. in MySQL 5.0 does not support
autodiscovery of databases.  (See *Note mysql-cluster-limitations::.)
This means that, once the `world' database and its tables have been
created on one data node, you need to issue the `CREATE DATABASE world'
statement (beginning with MySQL 5.0.2, you may use `CREATE SCHEMA
world' instead), followed by *Note `FLUSH TABLES': flush. on each SQL
node in the cluster. This causes the node to recognize the database and
read its table definitions.

Running *Note `SELECT': select. queries on the SQL node is no different
from running them on any other instance of a MySQL server. To run
queries from the command line, you first need to log in to the MySQL
Monitor in the usual way (specify the `root' password at the `Enter
password:' prompt):

     shell> mysql -u root -p
     Enter password:
     Welcome to the MySQL monitor.  Commands end with ; or \g.
     Your MySQL connection id is 1 to server version: 5.0.95

     Type 'help;' or '\h' for help. Type '\c' to clear the buffer.

     mysql>

We simply use the MySQL server's `root' account and assume that you
have followed the standard security precautions for installing a MySQL
server, including setting a strong `root' password. For more
information, see *Note default-privileges::.

It is worth taking into account that Cluster nodes do _not_ make use of
the MySQL privilege system when accessing one another. Setting or
changing MySQL user accounts (including the `root' account) effects
only applications that access the SQL node, not interaction between
nodes. See *Note mysql-cluster-security-mysql-privileges::, for more
information.

If you did not modify the `ENGINE' clauses in the table definitions
prior to importing the SQL script, you should run the following
statements at this point:

     mysql> USE world;
     mysql> ALTER TABLE City ENGINE=NDBCLUSTER;
     mysql> ALTER TABLE Country ENGINE=NDBCLUSTER;
     mysql> ALTER TABLE CountryLanguage ENGINE=NDBCLUSTER;

Selecting a database and running a `SELECT' query against a table in
that database is also accomplished in the usual manner, as is exiting
the MySQL Monitor:

     mysql> USE world;
     mysql> SELECT Name, Population FROM City ORDER BY Population DESC LIMIT 5;
     +-----------+------------+
     | Name      | Population |
     +-----------+------------+
     | Bombay    |   10500000 |
     | Seoul     |    9981619 |
     | Sa~o Paulo |    9968485 |
     | Shanghai  |    9696300 |
     | Jakarta   |    9604900 |
     +-----------+------------+
     5 rows in set (0.34 sec)

     mysql> \q
     Bye

     shell>

Applications that use MySQL can employ standard APIs to access *Note
`NDB': mysql-cluster. tables. It is important to remember that your
application must access the SQL node, and not the management or data
nodes. This brief example shows how we might execute the *Note
`SELECT': select. statement just shown by using the PHP 5.X `mysqli'
extension running on a Web server elsewhere on the network:

     <!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN"
       "http://www.w3.org/TR/html4/loose.dtd">
     <html>
     <head>
       <meta http-equiv="Content-Type"
                content="text/html; charset=iso-8859-1">
       <title>SIMPLE mysqli SELECT</title>
     </head>
     <body>
     <?php
       # connect to SQL node:
       $link = new mysqli('192.168.0.20', 'root', 'ROOT_PASSWORD', 'world');
       # parameters for mysqli constructor are:
       #   host, user, password, database

       if( mysqli_connect_errno() )
         die("Connect failed: " . mysqli_connect_error());

       $query = "SELECT Name, Population
                 FROM City
                 ORDER BY Population DESC
                 LIMIT 5";

       # if no errors...
       if( $result = $link->query($query) )
       {
     ?>
     <table border="1" width="40%" cellpadding="4" cellspacing ="1">
       <tbody>
       <tr>
         <th width="10%">City</th>
         <th>Population</th>
       </tr>
     <?
         # then display the results...
         while($row = $result->fetch_object())
           printf("<tr>\n  <td align=\"center\">%s</td><td>%d</td>\n</tr>\n",
                   $row->Name, $row->Population);
     ?>
       </tbody
     </table>
     <?
       # ...and verify the number of rows that were retrieved
         printf("<p>Affected rows: %d</p>\n", $link->affected_rows);
       }
       else
         # otherwise, tell us what went wrong
         echo mysqli_error();

       # free the result set and the mysqli connection object
       $result->close();
       $link->close();
     ?>
     </body>
     </html>

We assume that the process running on the Web server can reach the IP
address of the SQL node.

In a similar fashion, you can use the MySQL C API, Perl-DBI,
Python-mysql, or MySQL Connectors to perform the tasks of data
definition and manipulation just as you would normally with MySQL.


File: manual.info,  Node: mysql-cluster-install-shutdown-restart,  Next: mysql-cluster-upgrade-downgrade,  Prev: mysql-cluster-install-example-data,  Up: mysql-cluster-installation

17.2.5 Safe Shutdown and Restart of MySQL Cluster
-------------------------------------------------

To shut down the cluster, enter the following command in a shell on the
machine hosting the management node:

     shell> ndb_mgm -e shutdown

The `-e' option here is used to pass a command to the *Note `ndb_mgm':
mysql-cluster-programs-ndb-mgm. client from the shell. (See *Note
mysql-cluster-program-options-common::, for more information about this
option.) The command causes the *Note `ndb_mgm':
mysql-cluster-programs-ndb-mgm, *Note `ndb_mgmd':
mysql-cluster-programs-ndb-mgmd, and any *Note `ndbd':
mysql-cluster-programs-ndbd. processes to terminate gracefully. Any SQL
nodes can be terminated using *Note `mysqladmin shutdown': mysqladmin.
and other means.

To restart the cluster, run these commands:

   * On the management host (`192.168.0.10' in our example setup):

          shell> ndb_mgmd -f /var/lib/mysql-cluster/config.ini

   * On each of the data node hosts (`192.168.0.30' and `192.168.0.40'):

          shell> ndbd

   * Use the *Note `ndb_mgm': mysql-cluster-programs-ndb-mgm. client to
     verify that both data nodes have started successfully.

   * On the SQL host (`192.168.0.20'):

          shell> mysqld_safe &

In a production setting, it is usually not desirable to shut down the
cluster completely. In many cases, even when making configuration
changes, or performing upgrades to the cluster hardware or software (or
both), which require shutting down individual host machines, it is
possible to do so without shutting down the cluster as a whole by
performing a _rolling restart_ of the cluster. For more information
about doing this, see *Note mysql-cluster-rolling-restart::.


File: manual.info,  Node: mysql-cluster-upgrade-downgrade,  Prev: mysql-cluster-install-shutdown-restart,  Up: mysql-cluster-installation

17.2.6 Upgrading and Downgrading MySQL Cluster
----------------------------------------------

This section provides information about MySQL Cluster software and
table file compatibility between MySQL 5.0 releases with regard to
performing upgrades and downgrades as well as a compatibility matrix
and notes. You are expected already to be familiar with installing and
configuring a MySQL Cluster prior to attempting an upgrade or
downgrade. See *Note mysql-cluster-configuration::.

*Important*:

Only compatibility between MySQL versions with regard to *Note
`NDBCLUSTER': mysql-cluster. is taken into account in this section, and
there are likely other issues to be considered. _As with any other
MySQL software upgrade or downgrade, you are strongly encouraged to
review the relevant portions of the MySQL Manual for the MySQL versions
from which and to which you intend to migrate, before attempting an
upgrade or downgrade of the MySQL Cluster software_. See *Note
upgrading::.

The following table shows Cluster upgrade and downgrade compatibility
between different releases of MySQL 5.0:

MySQL Cluster upgrade/downgrade compatibility, MySQL 5.0

* Notes *

   * MySQL 5.0.2 was the first public release in this series.

   * Direct upgrades or downgrades between MySQL Cluster 4.1 and 5.0
     are not supported; you must dump all *Note `NDBCLUSTER':
     mysql-cluster. tables using *Note `mysqldump': mysqldump, install
     the new version of the software, and then reload the tables from
     the dump.

   * Online downgrades from MySQL Cluster 5.0.12 to 5.0.11 (or earlier)
     are not supported.

   * You cannot restore with *Note `ndb_restore':
     mysql-cluster-programs-ndb-restore. to a MySQL 5.0 Cluster using a
     backup made from a Cluster running MySQL 5.1. You must use *Note
     `mysqldump': mysqldump. in such cases.

   * There was no public release of MySQL 5.0.23.


File: manual.info,  Node: mysql-cluster-configuration,  Next: mysql-cluster-programs,  Prev: mysql-cluster-installation,  Up: mysql-cluster

17.3 MySQL Cluster Configuration
================================

* Menu:

* mysql-cluster-quick::          Quick Test Setup of MySQL Cluster
* mysql-cluster-config-file::    MySQL Cluster Configuration Files
* mysql-cluster-params-overview::  Overview of MySQL Cluster Configuration Parameters
* mysql-cluster-options-variables::  MySQL Server Options and Variables for MySQL Cluster
* mysql-cluster-interconnects::  Using High-Speed Interconnects with MySQL Cluster

A MySQL server that is part of a MySQL Cluster differs in one chief
respect from a normal (nonclustered) MySQL server, in that it employs
the *Note `NDBCLUSTER': mysql-cluster. storage engine.  This engine is
also referred to simply as *Note `NDB': mysql-cluster, and the two
forms of the name are synonymous.

To avoid unnecessary allocation of resources, the server is configured
by default with the *Note `NDB': mysql-cluster.  storage engine
disabled. To enable *Note `NDB': mysql-cluster, you must modify the
server's `my.cnf' configuration file, or start the server with the
`--ndbcluster' option.

For more information about `--ndbcluster' and other MySQL server
options specific to MySQL Cluster, see *Note
mysql-cluster-program-options-mysqld::.

The MySQL server is a part of the cluster, so it also must know how to
access an MGM node to obtain the cluster configuration data. The
default behavior is to look for the MGM node on `localhost'. However,
should you need to specify that its location is elsewhere, this can be
done in `my.cnf' or on the MySQL server command line.  Before the *Note
`NDB': mysql-cluster. storage engine can be used, at least one MGM node
must be operational, as well as any desired data nodes.

*Note `NDB': mysql-cluster, the MySQL Cluster storage engine, is
available in binary distributions for Linux, Mac OS X, and Solaris. We
are working to support MySQL Cluster on all operating systems supported
by MySQL, including Windows. For information about installing MySQL
Cluster, see *Note mysql-cluster-installation::.


File: manual.info,  Node: mysql-cluster-quick,  Next: mysql-cluster-config-file,  Prev: mysql-cluster-configuration,  Up: mysql-cluster-configuration

17.3.1 Quick Test Setup of MySQL Cluster
----------------------------------------

To familiarize you with the basics, we will describe the simplest
possible configuration for a functional MySQL Cluster. After this, you
should be able to design your desired setup from the information
provided in the other relevant sections of this chapter.

First, you need to create a configuration directory such as
`/var/lib/mysql-cluster', by executing the following command as the
system `root' user:

     shell> mkdir /var/lib/mysql-cluster

In this directory, create a file named `config.ini' that contains the
following information. Substitute appropriate values for `HostName' and
`DataDir' as necessary for your system.

     # file "config.ini" - showing minimal setup consisting of 1 data node,
     # 1 management server, and 3 MySQL servers.
     # The empty default sections are not required, and are shown only for
     # the sake of completeness.
     # Data nodes must provide a hostname but MySQL Servers are not required
     # to do so.
     # If you don't know the hostname for your machine, use localhost.
     # The DataDir parameter also has a default value, but it is recommended to
     # set it explicitly.
     # Note: [db], [api], and [mgm] are aliases for [ndbd], [mysqld], and [ndb_mgmd],
     # respectively. [db] is deprecated and should not be used in new installations.

     [ndbd default]
     NoOfReplicas= 1

     [mysqld  default]
     [ndb_mgmd default]
     [tcp default]

     [ndb_mgmd]
     HostName= myhost.example.com

     [ndbd]
     HostName= myhost.example.com
     DataDir= /var/lib/mysql-cluster

     [mysqld]
     [mysqld]
     [mysqld]

You can now start the *Note `ndb_mgmd':
mysql-cluster-programs-ndb-mgmd. management server. By default, it
attempts to read the `config.ini' file in its current working
directory, so change location into the directory where the file is
located and then invoke *Note `ndb_mgmd':
mysql-cluster-programs-ndb-mgmd.:

     shell> cd /var/lib/mysql-cluster
     shell> ndb_mgmd

Then start a single data node by running *Note `ndbd':
mysql-cluster-programs-ndbd.:

     shell> ndbd

For command-line options which can be used when starting *Note `ndbd':
mysql-cluster-programs-ndbd, see *Note
mysql-cluster-program-options-common::.

By default, *Note `ndbd': mysql-cluster-programs-ndbd. looks for the
management server at `localhost' on port 1186.

*Note*:

If you have installed MySQL from a binary tarball, you will need to
specify the path of the *Note `ndb_mgmd':
mysql-cluster-programs-ndb-mgmd. and *Note `ndbd':
mysql-cluster-programs-ndbd. servers explicitly. (Normally, these will
be found in `/usr/local/mysql/bin'.)

Finally, change location to the MySQL data directory (usually
`/var/lib/mysql' or `/usr/local/mysql/data'), and make sure that the
`my.cnf' file contains the option necessary to enable the NDB storage
engine:

     [mysqld]
     ndbcluster

You can now start the MySQL server as usual:

     shell> mysqld_safe --user=mysql &

Wait a moment to make sure the MySQL server is running properly.  If
you see the notice `mysql ended', check the server's `.err' file to
find out what went wrong.

If all has gone well so far, you now can start using the cluster.
Connect to the server and verify that the *Note `NDBCLUSTER':
mysql-cluster. storage engine is enabled:

     shell> mysql
     Welcome to the MySQL monitor.  Commands end with ; or \g.
     Your MySQL connection id is 1 to server version: 5.0.95

     Type 'help;' or '\h' for help. Type '\c' to clear the buffer.

     mysql> SHOW ENGINES\G
     ...
     *************************** 12. row ***************************
     Engine: NDBCLUSTER
     Support: YES
     Comment: Clustered, fault-tolerant, memory-based tables
     *************************** 13. row ***************************
     Engine: NDB
     Support: YES
     Comment: Alias for NDBCLUSTER
     ...

The row numbers shown in the preceding example output may be different
from those shown on your system, depending upon how your server is
configured.

Try to create an *Note `NDBCLUSTER': mysql-cluster. table:

     shell> mysql
     mysql> USE test;
     Database changed

     mysql> CREATE TABLE ctest (i INT) ENGINE=NDBCLUSTER;
     Query OK, 0 rows affected (0.09 sec)

     mysql> SHOW CREATE TABLE ctest \G
     *************************** 1. row ***************************
            Table: ctest
     Create Table: CREATE TABLE `ctest` (
       `i` int(11) default NULL
     ) ENGINE=ndbcluster DEFAULT CHARSET=latin1
     1 row in set (0.00 sec)

To check that your nodes were set up properly, start the management
client:

     shell> ndb_mgm

Use the `SHOW' command from within the management client to obtain a
report on the cluster's status:

     ndb_mgm> SHOW
     Cluster Configuration
     ---------------------
     [ndbd(NDB)]     1 node(s)
     id=2    @127.0.0.1  (Version: 3.5.3, Nodegroup: 0, Master)

     [ndb_mgmd(MGM)] 1 node(s)
     id=1    @127.0.0.1  (Version: 3.5.3)

     [mysqld(API)]   3 node(s)
     id=3    @127.0.0.1  (Version: 3.5.3)
     id=4 (not connected, accepting connect from any host)
     id=5 (not connected, accepting connect from any host)

At this point, you have successfully set up a working MySQL Cluster.
You can now store data in the cluster by using any table created with
`ENGINE=NDBCLUSTER' or its alias `ENGINE=NDB'.


File: manual.info,  Node: mysql-cluster-config-file,  Next: mysql-cluster-params-overview,  Prev: mysql-cluster-quick,  Up: mysql-cluster-configuration

17.3.2 MySQL Cluster Configuration Files
----------------------------------------

* Menu:

* mysql-cluster-config-example::  MySQL Cluster Configuration: Basic Example
* mysql-cluster-connectstring::  The MySQL Cluster Connectstring
* mysql-cluster-computer-definition::  Defining Computers in a MySQL Cluster
* mysql-cluster-mgm-definition::  Defining a MySQL Cluster Management Server
* mysql-cluster-ndbd-definition::  Defining MySQL Cluster Data Nodes
* mysql-cluster-api-definition::  Defining SQL and Other API Nodes in a MySQL Cluster
* mysql-cluster-tcp-definition::  MySQL Cluster TCP/IP Connections
* mysql-cluster-tcp-definition-direct::  MySQL Cluster TCP/IP Connections Using Direct Connections
* mysql-cluster-shm-definition::  MySQL Cluster Shared-Memory Connections
* mysql-cluster-sci-definition::  SCI Transport Connections in MySQL Cluster
* mysql-cluster-config-lcp-params::  Configuring MySQL Cluster Parameters for Local Checkpoints

Configuring MySQL Cluster requires working with two files:

   * `my.cnf': Specifies options for all MySQL Cluster executables.
     This file, with which you should be familiar with from previous
     work with MySQL, must be accessible by each executable running in
     the cluster.

   * `config.ini': This file, sometimes known as the _global
     configuration file_, is read only by the MySQL Cluster management
     server, which then distributes the information contained therein
     to all processes participating in the cluster. `config.ini'
     contains a description of each node involved in the cluster.  This
     includes configuration parameters for data nodes and configuration
     parameters for connections between all nodes in the cluster. For a
     quick reference to the sections that can appear in this file, and
     what sorts of configuration parameters may be placed in each
     section, see Sections of the `config.ini' File.

We are continuously making improvements in Cluster configuration and
attempting to simplify this process. Although we strive to maintain
backward compatibility, there may be times when introduce an
incompatible change. In such cases we will try to let Cluster users
know in advance if a change is not backward compatible. If you find
such a change and we have not documented it, please report it in the
MySQL bugs database using the instructions given in *Note bug-reports::.


File: manual.info,  Node: mysql-cluster-config-example,  Next: mysql-cluster-connectstring,  Prev: mysql-cluster-config-file,  Up: mysql-cluster-config-file

17.3.2.1 MySQL Cluster Configuration: Basic Example
...................................................

To support MySQL Cluster, you will need to update `my.cnf' as shown in
the following example.  You may also specify these parameters on the
command line when invoking the executables.

*Note*:

The options shown here should not be confused with those that are used
in `config.ini' global configuration files. Global configuration
options are discussed later in this section.

     # my.cnf
     # example additions to my.cnf for MySQL Cluster
     # (valid in MySQL 5.0)

     # enable ndbcluster storage engine, and provide connectstring for
     # management server host (default port is 1186)
     [mysqld]
     ndbcluster
     ndb-connectstring=ndb_mgmd.mysql.com

     # provide connectstring for management server host (default port: 1186)
     [ndbd]
     connect-string=ndb_mgmd.mysql.com

     # provide connectstring for management server host (default port: 1186)
     [ndb_mgm]
     connect-string=ndb_mgmd.mysql.com

     # provide location of cluster configuration file
     [ndb_mgmd]
     config-file=/etc/config.ini

(For more information on connectstrings, see *Note
mysql-cluster-connectstring::.)

     # my.cnf
     # example additions to my.cnf for MySQL Cluster
     # (will work on all versions)

     # enable ndbcluster storage engine, and provide connectstring for management
     # server host to the default port 1186
     [mysqld]
     ndbcluster
     ndb-connectstring=ndb_mgmd.mysql.com:1186

*Important*:

Once you have started a *Note `mysqld': mysqld. process with the *Note
`NDBCLUSTER': mysql-cluster. and `ndb-connectstring' parameters in the
`[mysqld]' in the `my.cnf' file as shown previously, you cannot execute
any *Note `CREATE TABLE': create-table. or *Note `ALTER TABLE':
alter-table. statements without having actually started the cluster.
Otherwise, these statements will fail with an error. _This is by
design_.

You may also use a separate `[mysql_cluster]' section in the cluster
`my.cnf' file for settings to be read and used by all executables:

     # cluster-specific settings
     [mysql_cluster]
     ndb-connectstring=ndb_mgmd.mysql.com:1186

For additional *Note `NDB': mysql-cluster. variables that can be set in
the `my.cnf' file, see *Note mysql-cluster-system-variables::.

The MySQL Cluster global configuration file is named `config.ini' by
default. It is read by *Note `ndb_mgmd':
mysql-cluster-programs-ndb-mgmd. at startup and can be placed anywhere.
Its location and name are specified by using `--config-file=PATH_NAME'
on the *Note `ndb_mgmd': mysql-cluster-programs-ndb-mgmd. command line.
If the configuration file is not specified, *Note `ndb_mgmd':
mysql-cluster-programs-ndb-mgmd.  by default tries to read a file named
`config.ini' located in the current working directory.

The global configuration file for MySQL Cluster uses INI format, which
consists of sections preceded by section headings (surrounded by square
brackets), followed by the appropriate parameter names and values. One
deviation from the standard INI format is that the parameter name and
value can be separated by a colon (``:'') as well as the equal sign
(``=''); however, the equal sign is preferred. Another deviation is
that sections are not uniquely identified by section name. Instead,
unique sections (such as two different nodes of the same type) are
identified by a unique ID specified as a parameter within the section.

Default values are defined for most parameters, and can also be
specified in `config.ini'.  (_Exception_: The `NoOfReplicas'
configuration parameter has no default value, and must always be
specified explicitly in the `[ndbd default]' section.) To create a
default value section, simply add the word `default' to the section
name. For example, an `[ndbd]' section contains parameters that apply
to a particular data node, whereas an `[ndbd default]' section contains
parameters that apply to all data nodes. Suppose that all data nodes
should use the same data memory size. To configure them all, create an
`[ndbd default]' section that contains a `DataMemory' line to specify
the data memory size.

The global configuration file must define the computers and nodes
involved in the cluster and on which computers these nodes are located.
An example of a simple configuration file for a cluster consisting of
one management server, two data nodes and two MySQL servers is shown
here:

     # file "config.ini" - 2 data nodes and 2 SQL nodes
     # This file is placed in the startup directory of ndb_mgmd (the
     # management server)
     # The first MySQL Server can be started from any host. The second
     # can be started only on the host mysqld_5.mysql.com

     [ndbd default]
     NoOfReplicas= 2
     DataDir= /var/lib/mysql-cluster

     [ndb_mgmd]
     Hostname= ndb_mgmd.mysql.com
     DataDir= /var/lib/mysql-cluster

     [ndbd]
     HostName= ndbd_2.mysql.com

     [ndbd]
     HostName= ndbd_3.mysql.com

     [mysqld]
     [mysqld]
     HostName= mysqld_5.mysql.com

Each node has its own section in the `config.ini' file. For example,
this cluster has two data nodes, so the preceding configuration file
contains two `[ndbd]' sections defining these nodes.

*Note*:

Do not place comments on the same line as a section heading in the
`config.ini' file; this causes the management server not to start
because it cannot parse the configuration file in such cases.

*Sections of the `config.ini' File*

There are six different sections that you can use in the `config.ini'
configuration file, as described in the following list:

   * `[computer]': Defines cluster hosts. This is not required to
     configure a viable MySQL Cluster, but be may used as a convenience
     when setting up a large cluster.  See *Note
     mysql-cluster-computer-definition::, for more information.

   * `[ndbd]': Defines a cluster data node (*Note `ndbd':
     mysql-cluster-programs-ndbd. process). See *Note
     mysql-cluster-ndbd-definition::, for details.

   * `[mysqld]': Defines the cluster's MySQL server nodes (also called
     SQL or API nodes). For a discussion of SQL node configuration, see
     *Note mysql-cluster-api-definition::.

   * `[mgm]' or `[ndb_mgmd]': Defines a cluster management server (MGM)
     node. For information concerning the configuration of MGM nodes,
     see *Note mysql-cluster-mgm-definition::.

   * `[tcp]': Defines a TCP/IP connection between cluster nodes, with
     TCP/IP being the default connection protocol. Normally, `[tcp]' or
     `[tcp default]' sections are not required to set up a MySQL
     Cluster, as the cluster handles this automatically; however, it
     may be necessary in some situations to override the defaults
     provided by the cluster.  See *Note
     mysql-cluster-tcp-definition::, for information about available
     TCP/IP configuration parameters and how to use them. (You may also
     find *Note mysql-cluster-tcp-definition-direct:: to be of interest
     in some cases.)

   * `[shm]': Defines shared-memory connections between nodes. In MySQL
     5.0, it is enabled by default, but should still be considered
     experimental. For a discussion of SHM interconnects, see *Note
     mysql-cluster-shm-definition::.

   * `[sci]':Defines _Scalable Coherent Interface_ connections between
     cluster data nodes. Such connections require software which, while
     freely available, is not part of the MySQL Cluster distribution,
     as well as specialized hardware. See *Note
     mysql-cluster-sci-definition:: for detailed information about SCI
     interconnects.

You can define `default' values for each section. All Cluster parameter
names are case-insensitive, which differs from parameters specified in
`my.cnf' or `my.ini' files.


File: manual.info,  Node: mysql-cluster-connectstring,  Next: mysql-cluster-computer-definition,  Prev: mysql-cluster-config-example,  Up: mysql-cluster-config-file

17.3.2.2 The MySQL Cluster Connectstring
........................................

With the exception of the MySQL Cluster management server (*Note
`ndb_mgmd': mysql-cluster-programs-ndb-mgmd.), each node that is part
of a MySQL Cluster requires a _connectstring_ that points to the
management server's location. This connectstring is used in
establishing a connection to the management server as well as in
performing other tasks depending on the node's role in the cluster. The
syntax for a connectstring is as follows:

     [nodeid=NODE_ID, ]HOST-DEFINITION[, HOST-DEFINITION[, ...]]

     HOST-DEFINITION:
         HOST_NAME[:PORT_NUMBER]

`node_id' is an integer larger than 1 which identifies a node in
`config.ini'.  HOST_NAME is a string representing a valid Internet host
name or IP address.  PORT_NUMBER is an integer referring to a TCP/IP
port number.

     example 1 (long):    "nodeid=2,myhost1:1100,myhost2:1100,192.168.0.3:1200"
     example 2 (short):   "myhost1"

`localhost:1186' is used as the default connectstring value if none is
provided. If PORT_NUM is omitted from the connectstring, the default
port is 1186. This port should always be available on the network
because it has been assigned by IANA for this purpose (see
`http://www.iana.org/assignments/port-numbers' for details).

By listing multiple host definitions, it is possible to designate
several redundant management servers. A MySQL Cluster data or API node
attempts to contact successive management servers on each host in the
order specified, until a successful connection has been established.

There are a number of different ways to specify the connectstring:

   * Each executable has its own command-line option which enables
     specifying the management server at startup. (See the
     documentation for the respective executable.)

   * It is also possible to set the connectstring for all nodes in the
     cluster at once by placing it in a `[mysql_cluster]' section in
     the management server's `my.cnf' file.

   * For backward compatibility, two other options are available, using
     the same syntax:

       1. Set the `NDB_CONNECTSTRING' environment variable to contain
          the connectstring.

       2. Write the connectstring for each executable into a text file
          named `Ndb.cfg' and place this file in the executable's
          startup directory.

     However, these are now deprecated and should not be used for new
     installations.

The recommended method for specifying the connectstring is to set it on
the command line or in the `my.cnf' file for each executable.

The maximum length of a connectstring is 1024 characters.


File: manual.info,  Node: mysql-cluster-computer-definition,  Next: mysql-cluster-mgm-definition,  Prev: mysql-cluster-connectstring,  Up: mysql-cluster-config-file

17.3.2.3 Defining Computers in a MySQL Cluster
..............................................

The `[computer]' section has no real significance other than serving as
a way to avoid the need of defining host names for each node in the
system. All parameters mentioned here are required.

   *  `Id'

     Options for id-computer      *Restart Type*       initial,        
                          node            
                          *Permitted        
                          Values          
                          *               
     *Type*               `string'        
     *Default*            `'              
     *Range*              ` .. '          


     This is a unique identifier, used to refer to the host computer
     elsewhere in the configuration file.

     *Important*:

     The computer ID is _not_ the same as the node ID used for a
     management, API, or data node.  Unlike the case with node IDs, you
     cannot use `NodeId' in place of `Id' in the `[computer]' section
     of the `config.ini' file.

   *  `HostName'

     Options for hostname-computer      *Restart Type*       system          
                          *Permitted        
                          Values          
                          *               
     *Type*               `string'        
     *Default*            `'              
     *Range*              ` .. '          


     This is the computer's hostname or IP address.


File: manual.info,  Node: mysql-cluster-mgm-definition,  Next: mysql-cluster-ndbd-definition,  Prev: mysql-cluster-computer-definition,  Up: mysql-cluster-config-file

17.3.2.4 Defining a MySQL Cluster Management Server
...................................................

The `[ndb_mgmd]' section is used to configure the behavior of the
management server. `[mgm]' can be used as an alias; the two section
names are equivalent.  All parameters in the following list are
optional and assume their default values if omitted.

*Note*:

If neither the `ExecuteOnComputer' nor the `HostName' parameter is
present, the default value `localhost' will be assumed for both.

   *  `Id'

     Options for id-mgmd      *Deprecated*         5.1.51-ndb-7.1.9        
     *Restart Type*       node            
                          *Permitted        
                          Values          
                          *               
     *Type*               `numeric'        
     *Default*            `'              
     *Range*              `1 ..           
                          63'             


     Each node in the cluster has a unique identity, which is
     represented by an integer value in the range 1 to 63 inclusive.
     This ID is used by all internal cluster messages for addressing
     the node.

     In MySQL 5.0.15 and later, `NodeId' is a synonym for this
     parameter, and is the preferred form. In MySQL Cluster NDB 6.2 and
     later, `Id' is deprecated in favor of `NodeId' for identifying
     management nodes.

   *  `NodeId'

     Options for nodeid-mgmd      *Version Introduced* 5.0.15          
     *Restart Type*       node            
                          *Permitted        
                          Values          
                          (>=             
                          5.0.15)*        
     *Type*               `numeric'        
     *Default*            `'              
     *Range*              `1 ..           
                          63'             


     Beginning with MySQL 5.0.15, `NodeId' is available as a synonym
     for `Id'.

     In MySQL Cluster NDB 6.2 and later, `Id' is deprecated in favor of
     `NodeId' for identifying management nodes.

   * `ExecuteOnComputer'

     Options for executeoncomputer-mgmd      *Restart Type*       system          
                          *Permitted        
                          Values          
                          *               
     *Type*               `string'        
     *Default*            `'              
     *Range*              ` .. '          


     This refers to the `Id' set for one of the computers defined in a
     `[computer]' section of the `config.ini' file.

   * `PortNumber'

     Options for portnumber-mgmd      *Restart Type*       node            
                          *Permitted        
                          Values          
                          *               
     *Type*               `numeric'        
     *Default*            `1186'          
     *Range*              `0 ..           
                          64K'            


     This is the port number on which the management server listens for
     configuration requests and management commands.

   * `HostName'

     Options for hostname-mgmd      *Restart Type*       system          
                          *Permitted        
                          Values          
                          *               
     *Type*               `string'        
     *Default*            `'              
     *Range*              ` .. '          


     Specifying this parameter defines the hostname of the computer on
     which the management node is to reside. To specify a hostname
     other than `localhost', either this parameter or
     `ExecuteOnComputer' is required.

   * `LogDestination'

     Options for logdestination-mgmd      *Restart Type*       node            
                          *Permitted        
                          Values          
                          *               
     *Type*               `string'        
     *Default*            `FILE:filename=ndb_nodeid_cluster.log,maxsize=1000000,maxfiles=6'        
     *Range*              ` .. '          


     This parameter specifies where to send cluster logging
     information. There are three options in this regard--`CONSOLE',
     `SYSLOG', and `FILE'--with `FILE' being the default:

        * `CONSOLE' outputs the log to `stdout':

               CONSOLE

        * `SYSLOG' sends the log to a `syslog' facility, possible values
          being one of `auth', `authpriv', `cron', `daemon', `ftp',
          `kern', `lpr', `mail', `news', `syslog', `user', `uucp',
          `local0', `local1', `local2', `local3', `local4', `local5',
          `local6', or `local7'.

          *Note*:

          Not every facility is necessarily supported by every
          operating system.

               SYSLOG:facility=syslog

        * `FILE' pipes the cluster log output to a regular file on the
          same machine. The following values can be specified:

             * `filename': The name of the log file.

             * `maxsize': The maximum size (in bytes) to which the file
               can grow before logging rolls over to a new file. When
               this occurs, the old log file is renamed by appending .N
               to the file name, where N is the next number not yet
               used with this name.

             * `maxfiles': The maximum number of log files.

               FILE:filename=cluster.log,maxsize=1000000,maxfiles=6

          The default value for the `FILE' parameter is
          `FILE:filename=ndb_NODE_ID_cluster.log,maxsize=1000000,maxfiles=6',
          where NODE_ID is the ID of the node.

     It is possible to specify multiple log destinations separated by
     semicolons as shown here:

          CONSOLE;SYSLOG:facility=local0;FILE:filename=/var/log/mgmd

   * `ArbitrationRank'

     Options for arbitrationrank-mgmd      *Restart Type*       node            
                          *Permitted        
                          Values          
                          *               
     *Type*               `numeric'        
     *Default*            `1'             
     *Range*              `0 ..           
                          2'              


     This parameter is used to define which nodes can act as
     arbitrators. Only management nodes and SQL nodes can be
     arbitrators. `ArbitrationRank' can take one of the following
     values:

        * `0': The node will never be used as an arbitrator.

        * `1': The node has high priority; that is, it will be
          preferred as an arbitrator over low-priority nodes.

        * `2': Indicates a low-priority node which be used as an
          arbitrator only if a node with a higher priority is not
          available for that purpose.

     Normally, the management server should be configured as an
     arbitrator by setting its `ArbitrationRank' to 1 (the default for
     management nodes) and those for all SQL nodes to 0 (the default
     for SQL nodes).

   * `ArbitrationDelay'

     Options for arbitrationdelay-mgmd      *Restart Type*       node            
                          *Permitted        
                          Values          
                          *               
     *Type*               `numeric'        
     *Default*            `0'             
     *Range*              `0 ..           
                          4G'             


     An integer value which causes the management server's responses to
     arbitration requests to be delayed by that number of milliseconds.
     By default, this value is 0; it is normally not necessary to
     change it.

   * `DataDir'

     Options for datadir-mgmd      *Restart Type*       node            
                          *Permitted        
                          Values          
                          *               
     *Type*               `string'        
     *Default*            `.'             
     *Range*              ` .. '          


     This specifies the directory where output files from the
     management server will be placed. These files include cluster log
     files, process output files, and the daemon's process ID (PID)
     file. (For log files, this location can be overridden by setting
     the `FILE' parameter for `LogDestination' as discussed previously
     in this section.)

     The default value for this parameter is the directory in which
     *Note `ndb_mgmd': mysql-cluster-programs-ndb-mgmd. is located.

*Note*:

After making changes in a management node's configuration, it is
necessary to perform a rolling restart of the cluster for the new
configuration to take effect.

To add new management servers to a running MySQL Cluster, it is also
necessary to perform a rolling restart of all cluster nodes after
modifying any existing `config.ini' files. For more information about
issues arising when using multiple management nodes, see *Note
mysql-cluster-limitations-multiple-nodes::.


File: manual.info,  Node: mysql-cluster-ndbd-definition,  Next: mysql-cluster-api-definition,  Prev: mysql-cluster-mgm-definition,  Up: mysql-cluster-config-file

17.3.2.5 Defining MySQL Cluster Data Nodes
..........................................

The `[ndbd]' and `[ndbd default]' sections are used to configure the
behavior of the cluster's data nodes.

There are many parameters which control buffer sizes, pool sizes,
timeouts, and so forth. The only mandatory parameters are:

   * Either `ExecuteOnComputer' or `HostName', which must be defined in
     the local `[ndbd]' section.

   * The parameter `NoOfReplicas', which must be defined in the`[ndbd
     default]'section, as it is common to all Cluster data nodes.

Most data node parameters are set in the `[ndbd default]' section. Only
those parameters explicitly stated as being able to set local values
are permitted to be changed in the `[ndbd]' section. Where present,
`HostName', `Id' and `ExecuteOnComputer' _must_ be defined in the local
`[ndbd]' section, and not in any other section of `config.ini'. In
other words, settings for these parameters are specific to one data
node.

For those parameters affecting memory usage or buffer sizes, it is
possible to use `K', `M', or `G' as a suffix to indicate units of 1024,
1024x1024, or 1024x1024x1024. (For example, `100K' means 100 x 1024 =
102400.)  Parameter names and values are currently case-sensitive.

Identifying data nodes

The `Id' value (that is, the data node identifier) can be allocated on
the command line when the node is started or in the configuration file.

   *  `Id'

     Options for id-ndbd      *Deprecated*         5.1.51-ndb-7.1.9        
     *Restart Type*       node            
                          *Permitted        
                          Values          
                          *               
     *Type*               `numeric'        
     *Default*            `'              
     *Range*              `1 ..           
                          48'             


     This is the node ID used as the address of the node for all
     cluster internal messages. For data nodes, this is an integer in
     the range 1 to 48 inclusive. Each node in the cluster must have a
     unique identifier.

     In MySQL 5.0.15 and later, `NodeId' is a synonym for this
     parameter, and is the preferred form. In MySQL Cluster NDB 6.2 and
     later, `Id' is deprecated in favor of `NodeId' for identifying
     data nodes.

   *  `NodeId'

     Options for nodeid-ndbd      *Version Introduced* 5.0.15          
     *Restart Type*       node            
                          *Permitted        
                          Values          
                          (>=             
                          5.0.15)*        
     *Type*               `numeric'        
     *Default*            `'              
     *Range*              `1 ..           
                          48'             


     Beginning with MySQL 5.0.15, `NodeId' is available as a synonym
     for `Id'.

     In MySQL Cluster NDB 6.2 and later, `Id' is deprecated in favor of
     `NodeId' for identifying management nodes.

   * `ExecuteOnComputer'

     Options for executeoncomputer-ndbd      *Restart Type*       system          
                          *Permitted        
                          Values          
                          *               
     *Type*               `string'        
     *Default*            `'              
     *Range*              ` .. '          


     This refers to the `Id' set for one of the computers defined in a
     `[computer]' section.

   * `HostName'

     Options for hostname-ndbd      *Restart Type*       system          
                          *Permitted        
                          Values          
                          *               
     *Type*               `string'        
     *Default*            `localhost'        
     *Range*              ` .. '          


     Specifying this parameter defines the hostname of the computer on
     which the data node is to reside. To specify a hostname other than
     `localhost', either this parameter or `ExecuteOnComputer' is
     required.

   * `ServerPort'

     Options for serverport-ndbd      *Restart Type*       node            
                          *Permitted        
                          Values          
                          *               
     *Type*               `numeric'        
     *Default*            `'              
     *Range*              `1 ..           
                          64K'            


     Each node in the cluster uses a port to connect to other nodes. By
     default, this port is allocated dynamically in such a way as to
     ensure that no two nodes on the same host computer receive the
     same port number, so it should normally not be necessary to
     specify a value for this parameter.

     However, if you need to be able to open specific ports in a
     firewall to permit communication between data nodes and API nodes
     (including SQL nodes), you can set this parameter to the number of
     the desired port in an `[ndbd]' section or (if you need to do this
     for multiple data nodes) the `[ndbd default]' section of the
     `config.ini' file, and then open the port having that number for
     incoming connections from SQL nodes, API nodes, or both.

     *Note*:

     Connections from data nodes to management nodes is done using the
     *Note `ndb_mgmd': mysql-cluster-programs-ndb-mgmd. management port
     (the management server's `PortNumber'; see *Note
     mysql-cluster-mgm-definition::) so outgoing connections to that
     port from any data nodes should always be permitted.

   * `NoOfReplicas'

     Options for noofreplicas-ndbd      *Restart Type*       initial,        
                          system          
                          *Permitted        
                          Values          
                          *               
     *Type*               `numeric'        
     *Default*            `None'          
     *Range*              `1 ..           
                          4'              
                          *Permitted        
                          Values          
                          *               
     *Type*               `numeric'        
     *Default*            `None'          
     *Range*              `1 ..           
                          4'              
                          *Permitted        
                          Values          
                          *               
     *Type*               `numeric'        
     *Default*            `2'             
     *Range*              `1 ..           
                          4'              
                          *Permitted        
                          Values          
                          *               
     *Type*               `numeric'        
     *Default*            `2'             
     *Range*              `1 ..           
                          4'              


     This global parameter can be set only in the `[ndbd default]'
     section, and defines the number of replicas for each table stored
     in the cluster. This parameter also specifies the size of node
     groups. A node group is a set of nodes all storing the same
     information.

     Node groups are formed implicitly. The first node group is formed
     by the set of data nodes with the lowest node IDs, the next node
     group by the set of the next lowest node identities, and so on. By
     way of example, assume that we have 4 data nodes and that
     `NoOfReplicas' is set to 2. The four data nodes have node IDs 2,
     3, 4 and 5. Then the first node group is formed from nodes 2 and 3,
     and the second node group by nodes 4 and 5. It is important to
     configure the cluster in such a manner that nodes in the same node
     groups are not placed on the same computer because a single
     hardware failure would cause the entire cluster to fail.

     If no node IDs are provided, the order of the data nodes will be
     the determining factor for the node group. Whether or not explicit
     assignments are made, they can be viewed in the output of the
     management client's `SHOW' command.

     There is no default value for `NoOfReplicas'; the recommended
     value is 2 for most common usage scenarios.

     The maximum possible value is 4; _currently, only the values 1 and
     2 are actually supported_.

     *Important*:

     Setting `NoOfReplicas' to 1 means that there is only a single copy
     of all Cluster data; in this case, the loss of a single data node
     causes the cluster to fail because there are no additional copies
     of the data stored by that node.

     The value for this parameter must divide evenly into the number of
     data nodes in the cluster. For example, if there are two data
     nodes, then `NoOfReplicas' must be equal to either 1 or 2, since
     2/3 and 2/4 both yield fractional values; if there are four data
     nodes, then `NoOfReplicas' must be equal to 1, 2, or 4.

   * `DataDir'

     Options for datadir-ndbd      *Restart Type*       initial,        
                          node            
                          *Permitted        
                          Values          
                          *               
     *Type*               `string'        
     *Default*            `.'             
     *Range*              ` .. '          


     This parameter specifies the directory where trace files, log
     files, pid files and error logs are placed.

     The default is the data node process working directory.

   * `FileSystemPath'

     Options for filesystempath-ndbd      *Restart Type*       initial,        
                          node            
                          *Permitted        
                          Values          
                          *               
     *Type*               `string'        
     *Default*            `DataDir'        
     *Range*              ` .. '          


     This parameter specifies the directory where all files created for
     metadata, REDO logs, UNDO logs, and data files are placed. The
     default is the directory specified by `DataDir'.

     *Note*:

     This directory must exist before the *Note `ndbd':
     mysql-cluster-programs-ndbd. process is initiated.

     The recommended directory hierarchy for MySQL Cluster includes
     `/var/lib/mysql-cluster', under which a directory for the node's
     file system is created. The name of this subdirectory contains the
     node ID. For example, if the node ID is 2, this subdirectory is
     named `ndb_2_fs'.

   * `BackupDataDir'

     Options for backupdatadir-ndbd      *Restart Type*       initial,        
                          node            
                          *Permitted        
                          Values          
                          *               
     *Type*               `string'        
     *Default*            `FileSystemPath'        
     *Range*              ` .. '          


     This parameter specifies the directory in which backups are placed.

     *Important*:

     The string '`/BACKUP'' is always appended to this value. For
     example, if you set the value of `BackupDataDir' to
     `/var/lib/cluster-data', then all backups are stored under
     `/var/lib/cluster-data/BACKUP'. This also means that the
     _effective_ default backup location is the directory named
     `BACKUP' under the location specified by the `FileSystemPath'
     parameter.

*Data Memory, Index Memory, and String Memory*

`DataMemory' and `IndexMemory' are `[ndbd]' parameters specifying the
size of memory segments used to store the actual records and their
indexes. In setting values for these, it is important to understand how
`DataMemory' and `IndexMemory' are used, as they usually need to be
updated to reflect actual usage by the cluster:

   * `DataMemory'

     Options for datamemory-ndbd      *Restart Type*       node            
                          *Permitted        
                          Values          
                          *               
     *Type*               `numeric'        
     *Default*            `80M'           
     *Range*              `1M ..          
                          1024G'          


     This parameter defines the amount of space (in bytes) available
     for storing database records. The entire amount specified by this
     value is allocated in memory, so it is extremely important that
     the machine has sufficient physical memory to accommodate it.

     The memory allocated by `DataMemory' is used to store both the
     actual records and indexes. Each record is currently of fixed
     size. (Even *Note `VARCHAR': char. columns are stored as
     fixed-width columns.) There is a 16-byte overhead on each record;
     an additional amount for each record is incurred because it is
     stored in a 32KB page with 128 byte page overhead (see below).
     There is also a small amount wasted per page due to the fact that
     each record is stored in only one page.

     The maximum record size is currently 8052 bytes.

     The memory space defined by `DataMemory' is also used to store
     ordered indexes, which use about 10 bytes per record. Each table
     row is represented in the ordered index. A common error among
     users is to assume that all indexes are stored in the memory
     allocated by `IndexMemory', but this is not the case: Only primary
     key and unique hash indexes use this memory; ordered indexes use
     the memory allocated by `DataMemory'. However, creating a primary
     key or unique hash index also creates an ordered index on the same
     keys, unless you specify `USING HASH' in the index creation
     statement. This can be verified by running *Note `ndb_desc -d
     DB_NAME TABLE_NAME': mysql-cluster-programs-ndb-desc. in the
     management client.

     The memory space allocated by `DataMemory' consists of 32KB pages,
     which are allocated to table fragments. Each table is normally
     partitioned into the same number of fragments as there are data
     nodes in the cluster.  Thus, for each node, there are the same
     number of fragments as are set in `NoOfReplicas'.

     In addition, due to the way in which new pages are allocated when
     the capacity of the current page is exhausted, there is an
     additional overhead of approximately 18.75%. When more
     `DataMemory' is required, more than one new page is allocated,
     according to the following formula:

          number of new pages = FLOOR(number of current pages x 0.1875) + 1

     For example, if 15 pages are currently allocated to a given table
     and an insert to this table requires additional storage space, the
     number of new pages allocated to the table is `FLOOR(15 x 0.1875)
     + 1 = FLOOR(2.8125) + 1 = 2 + 1 = 3'. Now 15 + 3 = 18 memory pages
     are allocated to the table. When the last of these 18 pages
     becomes full, `FLOOR(18 x 0.1875) + 1 = FLOOR(3.3750) + 1 = 3 + 1 =
     4' new pages are allocated, so the total number of pages allocated
     to the table is now 22.

     Once a page has been allocated, it is currently not possible to
     return it to the pool of free pages, except by deleting the table.
     (This also means that `DataMemory' pages, once allocated to a
     given table, cannot be used by other tables.) Performing a node
     recovery also compresses the partition because all records are
     inserted into empty partitions from other live nodes.

     The `DataMemory' memory space also contains UNDO information: For
     each update, a copy of the unaltered record is allocated in the
     `DataMemory'.  There is also a reference to each copy in the
     ordered table indexes. Unique hash indexes are updated only when
     the unique index columns are updated, in which case a new entry in
     the index table is inserted and the old entry is deleted upon
     commit. For this reason, it is also necessary to allocate enough
     memory to handle the largest transactions performed by
     applications using the cluster. In any case, performing a few
     large transactions holds no advantage over using many smaller
     ones, for the following reasons:

        * Large transactions are not any faster than smaller ones

        * Large transactions increase the number of operations that are
          lost and must be repeated in event of transaction failure

        * Large transactions use more memory

     The default value for `DataMemory' is 80MB; the minimum is 1MB.
     There is no maximum size, but in reality the maximum size has to
     be adapted so that the process does not start swapping when the
     limit is reached. This limit is determined by the amount of
     physical RAM available on the machine and by the amount of memory
     that the operating system may commit to any one process. 32-bit
     operating systems are generally limited to 2-4GB per process;
     64-bit operating systems can use more. For large databases, it may
     be preferable to use a 64-bit operating system for this reason.

   * `IndexMemory'

     Options for indexmemory-ndbd      *Restart Type*       node            
                          *Permitted        
                          Values          
                          *               
     *Type*               `numeric'        
     *Default*            `18M'           
     *Range*              `1M ..          
                          1T'             


     This parameter controls the amount of storage used for hash
     indexes in MySQL Cluster. Hash indexes are always used for primary
     key indexes, unique indexes, and unique constraints.  Note that
     when defining a primary key and a unique index, two indexes will
     be created, one of which is a hash index used for all tuple
     accesses as well as lock handling. It is also used to enforce
     unique constraints.

     The size of the hash index is 25 bytes per record, plus the size
     of the primary key. For primary keys larger than 32 bytes another
     8 bytes is added.

     The default value for `IndexMemory' is 18MB. The minimum is 1MB.

   * `StringMemory'

     Options for stringmemory-ndbd      *Restart Type*       system          
                          *Permitted        
                          Values          
                          *               
     *Type*               `numeric'        
     *Default*            `0'             
     *Range*              `0 ..           
                          4G'             


     This parameter determines how much memory is allocated for strings
     such as table names, and is specified in an `[ndbd]' or `[ndbd
     default]' section of the `config.ini' file. A value between `0'
     and `100' inclusive is interpreted as a percent of the maximum
     default value, which is calculated based on a number of factors
     including the number of tables, maximum table name size, maximum
     size of `.FRM' files, `MaxNoOfTriggers', maximum column name size,
     and maximum default column value. In general it is safe to assume
     that the maximum default value is approximately 5 MB for a MySQL
     Cluster having 1000 tables.

     A value greater than `100' is interpreted as a number of bytes.

     In MySQL 5.0, the default value is `100'--that is, 100 percent of
     the default maximum, or roughly 5 MB. It is possible to reduce
     this value safely, but it should never be less than 5 percent. If
     you encounter Error 773 `Out of string memory, please modify
     StringMemory config parameter: Permanent error: Schema error',
     this means that means that you have set the `StringMemory' value
     too low. `25' (25 percent) is not excessive, and should prevent
     this error from recurring in all but the most extreme conditions,
     as when there are hundreds or thousands of *Note `NDB':
     mysql-cluster.  tables with names whose lengths and columns whose
     number approach their permitted maximums.

The following example illustrates how memory is used for a table.
Consider this table definition:

     CREATE TABLE example (
       a INT NOT NULL,
       b INT NOT NULL,
       c INT NOT NULL,
       PRIMARY KEY(a),
       UNIQUE(b)
     ) ENGINE=NDBCLUSTER;

For each record, there are 12 bytes of data plus 12 bytes overhead.
Having no nullable columns saves 4 bytes of overhead.  In addition, we
have two ordered indexes on columns `a' and `b' consuming roughly 10
bytes each per record. There is a primary key hash index on the base
table using roughly 29 bytes per record. The unique constraint is
implemented by a separate table with `b' as primary key and `a' as a
column. This other table consumes an additional 29 bytes of index
memory per record in the `example' table as well 8 bytes of record data
plus 12 bytes of overhead.

Thus, for one million records, we need 58MB for index memory to handle
the hash indexes for the primary key and the unique constraint. We also
need 64MB for the records of the base table and the unique index table,
plus the two ordered index tables.

You can see that hash indexes takes up a fair amount of memory space;
however, they provide very fast access to the data in return. They are
also used in MySQL Cluster to handle uniqueness constraints.

Currently, the only partitioning algorithm is hashing and ordered
indexes are local to each node. Thus, ordered indexes cannot be used to
handle uniqueness constraints in the general case.

An important point for both `IndexMemory' and `DataMemory' is that the
total database size is the sum of all data memory and all index memory
for each node group. Each node group is used to store replicated
information, so if there are four nodes with two replicas, there will
be two node groups. Thus, the total data memory available is 2 x
`DataMemory' for each data node.

It is highly recommended that `DataMemory' and `IndexMemory' be set to
the same values for all nodes. Data distribution is even over all nodes
in the cluster, so the maximum amount of space available for any node
can be no greater than that of the smallest node in the cluster.

`DataMemory' and `IndexMemory' can be changed, but decreasing either of
these can be risky; doing so can easily lead to a node or even an
entire MySQL Cluster that is unable to restart due to there being
insufficient memory space. Increasing these values should be
acceptable, but it is recommended that such upgrades are performed in
the same manner as a software upgrade, beginning with an update of the
configuration file, and then restarting the management server followed
by restarting each data node in turn.

Updates do not increase the amount of index memory used. Inserts take
effect immediately; however, rows are not actually deleted until the
transaction is committed.

Transaction parameters

The next three `[ndbd]' parameters that we discuss are important
because they affect the number of parallel transactions and the sizes
of transactions that can be handled by the system.
`MaxNoOfConcurrentTransactions' sets the number of parallel
transactions possible in a node.  `MaxNoOfConcurrentOperations' sets
the number of records that can be in update phase or locked
simultaneously.

Both of these parameters (especially `MaxNoOfConcurrentOperations') are
likely targets for users setting specific values and not using the
default value. The default value is set for systems using small
transactions, to ensure that these do not use excessive memory.

   * `MaxNoOfConcurrentTransactions'

     Options for maxnoofconcurrenttransactions-ndbd      *Restart Type*       system          
                          *Permitted        
                          Values          
                          *               
     *Type*               `numeric'        
     *Default*            `4096'          
     *Range*              `32 ..          
                          4G'             


     Each cluster data node requires a transaction record for each
     active transaction in the cluster. The task of coordinating
     transactions is distributed among all of the data nodes. The total
     number of transaction records in the cluster is the number of
     transactions in any given node times the number of nodes in the
     cluster.

     Transaction records are allocated to individual MySQL servers.
     Each connection to a MySQL server requires at least one
     transaction record, plus an additional transaction object per
     table accessed by that connection. This means that a reasonable
     minimum for this parameter is

          MaxNoOfConcurrentTransactions =
              (maximum number of tables accessed in any single transaction + 1)
              * number of cluster SQL nodes

     Suppose that there are 4 SQL nodes using the cluster. A single
     join involving 5 tables requires 6 transaction records; if there
     are 5 such joins in a transaction, then 5 * 6 = 30 transaction
     records are required for this transaction, per MySQL server, or 30
     * 4 = 120 transaction records total.

     This parameter must be set to the same value for all cluster data
     nodes. This is due to the fact that, when a data node fails, the
     oldest surviving node re-creates the transaction state of all
     transactions that were ongoing in the failed node.

     Changing the value of `MaxNoOfConcurrentTransactions' requires a
     complete shutdown and restart of the cluster.

     The default value is 4096.

   * `MaxNoOfConcurrentOperations'

     Options for maxnoofconcurrentoperations-ndbd      *Restart Type*       node            
                          *Permitted        
                          Values          
                          *               
     *Type*               `numeric'        
     *Default*            `32K'           
     *Range*              `32 ..          
                          4G'             


     It is a good idea to adjust the value of this parameter according
     to the size and number of transactions. When performing
     transactions of only a few operations each and not involving a
     great many records, there is no need to set this parameter very
     high. When performing large transactions involving many records
     need to set this parameter higher.

     Records are kept for each transaction updating cluster data, both
     in the transaction coordinator and in the nodes where the actual
     updates are performed. These records contain state information
     needed to find UNDO records for rollback, lock queues, and other
     purposes.

     This parameter should be set to the number of records to be
     updated simultaneously in transactions, divided by the number of
     cluster data nodes. For example, in a cluster which has four data
     nodes and which is expected to handle 1,000,000 concurrent updates
     using transactions, you should set this value to 1000000 / 4 =
     250000.

     Read queries which set locks also cause operation records to be
     created. Some extra space is allocated within individual nodes to
     accommodate cases where the distribution is not perfect over the
     nodes.

     When queries make use of the unique hash index, there are actually
     two operation records used per record in the transaction. The
     first record represents the read in the index table and the second
     handles the operation on the base table.

     The default value is 32768.

     This parameter actually handles two values that can be configured
     separately. The first of these specifies how many operation
     records are to be placed with the transaction coordinator. The
     second part specifies how many operation records are to be local
     to the database.

     A very large transaction performed on an eight-node cluster
     requires as many operation records in the transaction coordinator
     as there are reads, updates, and deletes involved in the
     transaction. However, the operation records of the are spread over
     all eight nodes. Thus, if it is necessary to configure the system
     for one very large transaction, it is a good idea to configure the
     two parts separately. `MaxNoOfConcurrentOperations' will always be
     used to calculate the number of operation records in the
     transaction coordinator portion of the node.

     It is also important to have an idea of the memory requirements
     for operation records. These consume about 1KB per record.

   * `MaxNoOfLocalOperations'

     Options for maxnooflocaloperations-ndbd      *Restart Type*       node            
                          *Permitted        
                          Values          
                          *               
     *Type*               `numeric'        
     *Default*            `UNDEFINED'        
     *Range*              `32 ..          
                          4G'             


     By default, this parameter is calculated as 1.1 x
     `MaxNoOfConcurrentOperations'. This fits systems with many
     simultaneous transactions, none of them being very large. If there
     is a need to handle one very large transaction at a time and there
     are many nodes, it is a good idea to override the default value by
     explicitly specifying this parameter.

Transaction temporary storage

The next set of `[ndbd]' parameters is used to determine temporary
storage when executing a statement that is part of a Cluster
transaction. All records are released when the statement is completed
and the cluster is waiting for the commit or rollback.

The default values for these parameters are adequate for most
situations. However, users with a need to support transactions
involving large numbers of rows or operations may need to increase
these values to enable better parallelism in the system, whereas users
whose applications require relatively small transactions can decrease
the values to save memory.

   * `MaxNoOfConcurrentIndexOperations'

     Options for maxnoofconcurrentindexoperations-ndbd      *Restart Type*       node            
                          *Permitted        
                          Values          
                          *               
     *Type*               `numeric'        
     *Default*            `8K'            
     *Range*              `0 ..           
                          4G'             


     For queries using a unique hash index, another temporary set of
     operation records is used during a query's execution phase. This
     parameter sets the size of that pool of records.  Thus, this
     record is allocated only while executing a part of a query. As
     soon as this part has been executed, the record is released. The
     state needed to handle aborts and commits is handled by the normal
     operation records, where the pool size is set by the parameter
     `MaxNoOfConcurrentOperations'.

     The default value of this parameter is 8192. Only in rare cases of
     extremely high parallelism using unique hash indexes should it be
     necessary to increase this value. Using a smaller value is
     possible and can save memory if the DBA is certain that a high
     degree of parallelism is not required for the cluster.

   * `MaxNoOfFiredTriggers'

     Options for maxnooffiredtriggers-ndbd      *Restart Type*       node            
                          *Permitted        
                          Values          
                          *               
     *Type*               `numeric'        
     *Default*            `4000'          
     *Range*              `0 ..           
                          4G'             


     The default value of `MaxNoOfFiredTriggers' is 4000, which is
     sufficient for most situations. In some cases it can even be
     decreased if the DBA feels certain the need for parallelism in the
     cluster is not high.

     A record is created when an operation is performed that affects a
     unique hash index. Inserting or deleting a record in a table with
     unique hash indexes or updating a column that is part of a unique
     hash index fires an insert or a delete in the index table. The
     resulting record is used to represent this index table operation
     while waiting for the original operation that fired it to
     complete. This operation is short-lived but can still require a
     large number of records in its pool for situations with many
     parallel write operations on a base table containing a set of
     unique hash indexes.

   * `TransactionBufferMemory'

     Options for transactionbuffermemory-ndbd      *Restart Type*       node            
                          *Permitted        
                          Values          
                          *               
     *Type*               `numeric'        
     *Default*            `1M'            
     *Range*              `1K ..          
                          4G'             


     The memory affected by this parameter is used for tracking
     operations fired when updating index tables and reading unique
     indexes. This memory is used to store the key and column
     information for these operations. It is only very rarely that the
     value for this parameter needs to be altered from the default.

     The default value for `TransactionBufferMemory' is 1MB.

     Normal read and write operations use a similar buffer, whose usage
     is even more short-lived. The compile-time parameter
     `ZATTRBUF_FILESIZE' (found in
     `ndb/src/kernel/blocks/Dbtc/Dbtc.hpp') set to 4000 x 128 bytes
     (500KB). A similar buffer for key information, `ZDATABUF_FILESIZE'
     (also in `Dbtc.hpp') contains 4000 x 16 = 62.5KB of buffer space.
     `Dbtc' is the module that handles transaction coordination.

Scans and buffering

There are additional `[ndbd]' parameters in the `Dblqh' module (in
`ndb/src/kernel/blocks/Dblqh/Dblqh.hpp') that affect reads and updates.
These include `ZATTRINBUF_FILESIZE', set by default to 10000 x 128
bytes (1250KB) and `ZDATABUF_FILE_SIZE', set by default to 10000*16
bytes (roughly 156KB) of buffer space. To date, there have been neither
any reports from users nor any results from our own extensive tests
suggesting that either of these compile-time limits should be increased.

   * `MaxNoOfConcurrentScans'

     Options for maxnoofconcurrentscans-ndbd      *Restart Type*       node            
                          *Permitted        
                          Values          
                          *               
     *Type*               `numeric'        
     *Default*            `256'           
     *Range*              `2 ..           
                          500'            


     This parameter is used to control the number of parallel scans
     that can be performed in the cluster. Each transaction coordinator
     can handle the number of parallel scans defined for this
     parameter. Each scan query is performed by scanning all partitions
     in parallel. Each partition scan uses a scan record in the node
     where the partition is located, the number of records being the
     value of this parameter times the number of nodes. The cluster
     should be able to sustain `MaxNoOfConcurrentScans' scans
     concurrently from all nodes in the cluster.

     Scans are actually performed in two cases. The first of these
     cases occurs when no hash or ordered indexes exists to handle the
     query, in which case the query is executed by performing a full
     table scan. The second case is encountered when there is no hash
     index to support the query but there is an ordered index. Using
     the ordered index means executing a parallel range scan. The order
     is kept on the local partitions only, so it is necessary to
     perform the index scan on all partitions.

     The default value of `MaxNoOfConcurrentScans' is 256. The maximum
     value is 500.

   * `MaxNoOfLocalScans'

     Options for maxnooflocalscans-ndbd      *Restart Type*       node            
                          *Permitted        
                          Values          
                          *               
     *Type*               `numeric'        
     *Default*            `UNDEFINED'        
     *Range*              `32 ..          
                          4G'             


     Specifies the number of local scan records if many scans are not
     fully parallelized. If the number of local scan records is not
     provided, it is calculated as the product of
     `MaxNoOfConcurrentScans' and the number of data nodes in the
     system. The minimum value is 32.

   * `BatchSizePerLocalScan'

     Options for batchsizeperlocalscan-ndbd      *Restart Type*       node            
                          *Permitted        
                          Values          
                          *               
     *Type*               `numeric'        
     *Default*            `64'            
     *Range*              `1 ..           
                          992'            


     This parameter is used to calculate the number of lock records
     used to handle concurrent scan operations.

     The default value is 64; this value has a strong connection to the
     `BatchSize' defined in the SQL nodes.

   * `LongMessageBuffer'

     Options for longmessagebuffer-ndbd      *Restart Type*       node            
                          *Permitted        
                          Values          
                          *               
     *Type*               `numeric'        
     *Default*            `1M'            
     *Range*              `512K           
                          .. 4G'          
                          *Permitted        
                          Values          
                          *               
     *Type*               `numeric'        
     *Default*            `4M'            
     *Range*              `512K           
                          .. 4G'          


     This is an internal buffer used for passing messages within
     individual nodes and between nodes. Although it is highly unlikely
     that this would need to be changed, it is configurable. By
     default, it is set to 1MB.

Logging and checkpointing

The following `[ndbd]' parameters control log and checkpoint behavior.

   * `NoOfFragmentLogFiles'

     Options for nooffragmentlogfiles-ndbd      *Restart Type*       initial,        
                          node            
                          *Permitted        
                          Values          
                          *               
     *Type*               `numeric'        
     *Default*            `8'             
     *Range*              `3 ..           
                          4G'             


     This parameter sets the number of REDO log files for the node, and
     thus the amount of space allocated to REDO logging. Because the
     REDO log files are organized in a ring, it is extremely important
     that the first and last log files in the set (sometimes referred
     to as the `head' and `tail' log files, respectively) do not meet.
     When these approach one another too closely, the node begins
     aborting all transactions encompassing updates due to a lack of
     room for new log records.

     A `REDO' log record is not removed until three local checkpoints
     have been completed since that log record was inserted.
     Checkpointing frequency is determined by its own set of
     configuration parameters discussed elsewhere in this chapter.

     How these parameters interact and proposals for how to configure
     them are discussed in *Note mysql-cluster-config-lcp-params::.

     The default parameter value is 8, which means 8 sets of 4 16MB
     files for a total of 512MB. In other words, REDO log space is
     always allocated in blocks of 64MB. In scenarios requiring a great
     many updates, the value for `NoOfFragmentLogFiles' may need to be
     set as high as 300 or even higher to provide sufficient space for
     REDO logs.

     If the checkpointing is slow and there are so many writes to the
     database that the log files are full and the log tail cannot be
     cut without jeopardizing recovery, all updating transactions are
     aborted with internal error code 410 (`Out of log file space
     temporarily'). This condition prevails until a checkpoint has
     completed and the log tail can be moved forward.

     *Important*:

     This parameter cannot be changed `on the fly'; you must restart
     the node using `--initial'. If you wish to change this value for
     all data nodes in a running cluster, you can do so using a rolling
     node restart (using `--initial' when starting each data node).

   * `MaxNoOfOpenFiles'

     Options for maxnoofopenfiles-ndbd      *Restart Type*       node            


     This parameter sets a ceiling on how many internal threads to
     allocate for open files. _Any situation requiring a change in this
     parameter should be reported as a bug_.

     The default value is 40.

   * `MaxNoOfSavedMessages'

     Options for maxnoofsavedmessages-ndbd      *Restart Type*       node            
                          *Permitted        
                          Values          
                          *               
     *Type*               `numeric'        
     *Default*            `25'            
     *Range*              `0 ..           
                          4G'             


     This parameter sets the maximum number of trace files that are
     kept before overwriting old ones. Trace files are generated when,
     for whatever reason, the node crashes.

     The default is 25 trace files.

Metadata objects

The next set of `[ndbd]' parameters defines pool sizes for metadata
objects, used to define the maximum number of attributes, tables,
indexes, and trigger objects used by indexes, events, and replication
between clusters.  Note that these act merely as `suggestions' to the
cluster, and any that are not specified revert to the default values
shown.

   * `MaxNoOfAttributes'

     Options for maxnoofattributes-ndbd      *Restart Type*       node            
                          *Permitted        
                          Values          
                          *               
     *Type*               `numeric'        
     *Default*            `1000'          
     *Range*              `32 ..          
                          4G'             


     This parameter sets a suggested maximum number of attributes that
     can be defined in the cluster; like `MaxNoOfTables', it is not
     intended to function as a hard upper limit.

     A known issue in MySQL Cluster in MySQL 5.0 is that this parameter
     is occasionally treated as a hard limit for certain operations.
     This can lead to confusion when it is sometimes possible (or not
     possible, depending on the circumstances) to create more than
     `MaxNoOfAttributes' attributes. This is fixed in MySQL Cluster NDB
     6.3 and later. (Bug #61684)

     The default value is 1000, with the minimum possible value being
     32. The maximum is 4294967039. Each attribute consumes around 200
     bytes of storage per node due to the fact that all metadata is
     fully replicated on the servers.

     When setting `MaxNoOfAttributes', it is important to prepare in
     advance for any *Note `ALTER TABLE': alter-table. statements that
     you might want to perform in the future. This is due to the fact,
     during the execution of *Note `ALTER TABLE': alter-table. on a
     Cluster table, 3 times the number of attributes as in the original
     table are used, and a good practice is to permit double this
     amount. For example, if the MySQL Cluster table having the
     greatest number of attributes (GREATEST_NUMBER_OF_ATTRIBUTES) has
     100 attributes, a good starting point for the value of
     `MaxNoOfAttributes' would be `6 * GREATEST_NUMBER_OF_ATTRIBUTES =
     600'.

     You should also estimate the average number of attributes per
     table and multiply this by the total number of MySQL Cluster
     tables. If this value is larger than the value obtained in the
     previous paragraph, you should use the larger value instead.

     Assuming that you can create all desired tables without any
     problems, you should also verify that this number is sufficient by
     trying an actual *Note `ALTER TABLE': alter-table. after
     configuring the parameter. If this is not successful, increase
     `MaxNoOfAttributes' by another multiple of `MaxNoOfTables' and
     test it again.

   * `MaxNoOfTables'

     Options for maxnooftables-ndbd      *Restart Type*       node            
                          *Permitted        
                          Values          
                          (>=             
                          5.0.0)*         
     *Type*               `numeric'        
     *Default*            `128'           
     *Range*              `8 ..           
                          20320'          


     A table object is allocated for each table and for each unique
     hash index in the cluster. This parameter sets a suggested maximum
     number of table objects for the cluster as a whole; like
     `MaxNoOfAttributes', it is not intended to function as a hard
     upper limit.

     A known issue in MySQL Cluster in MySQL 5.0 is that this parameter
     is occasionally treated as a hard limit for certain operations.
     This can lead to confusion when it is sometimes possible (or not
     possible, depending on the circumstances) to create more than
     `MaxNoOfTables' tables. This is fixed in MySQL Cluster NDB 6.3 and
     later. (Bug #61684)

     For each attribute that has a *Note `BLOB': blob. data type an
     extra table is used to store most of the *Note `BLOB': blob. data.
     These tables also must be taken into account when defining the
     total number of tables.

     The default value of this parameter is 128. The minimum is 8 and
     the maximum is 20320. (This is a change from MySQL 4.1.)  Each
     table object consumes approximately 20KB per node.

     *Note*:

     The sum of `MaxNoOfTables', `MaxNoOfOrderedIndexes', and
     `MaxNoOfUniqueHashIndexes' must not exceed `2^32 - 2' (4294967294).

   * `MaxNoOfOrderedIndexes'

     Options for maxnooforderedindexes-ndbd      *Restart Type*       node            
                          *Permitted        
                          Values          
                          *               
     *Type*               `numeric'        
     *Default*            `128'           
     *Range*              `0 ..           
                          4G'             


     For each ordered index in the cluster, an object is allocated
     describing what is being indexed and its storage segments. By
     default, each index so defined also defines an ordered index. Each
     unique index and primary key has both an ordered index and a hash
     index.  `MaxNoOfOrderedIndexes' sets the total number of hash
     indexes that can be in use in the system at any one time.

     The default value of this parameter is 128. Each hash index object
     consumes approximately 10KB of data per node.

     *Note*:

     The sum of `MaxNoOfTables', `MaxNoOfOrderedIndexes', and
     `MaxNoOfUniqueHashIndexes' must not exceed `2^32 - 2' (4294967294).

   * `MaxNoOfUniqueHashIndexes'

     Options for maxnoofuniquehashindexes-ndbd      *Restart Type*       node            
                          *Permitted        
                          Values          
                          *               
     *Type*               `numeric'        
     *Default*            `64'            
     *Range*              `0 ..           
                          4G'             


     For each unique index that is not a primary key, a special table
     is allocated that maps the unique key to the primary key of the
     indexed table. By default, an ordered index is also defined for
     each unique index. To prevent this, you must specify the `USING
     HASH' option when defining the unique index.

     The default value is 64. Each index consumes approximately 15KB
     per node.

     *Note*:

     The sum of `MaxNoOfTables', `MaxNoOfOrderedIndexes', and
     `MaxNoOfUniqueHashIndexes' must not exceed `2^32 - 2' (4294967294).

   * `MaxNoOfTriggers'

     Options for maxnooftriggers-ndbd      *Restart Type*       node            
                          *Permitted        
                          Values          
                          *               
     *Type*               `numeric'        
     *Default*            `768'           
     *Range*              `0 ..           
                          4G'             


     Internal update, insert, and delete triggers are allocated for
     each unique hash index. (This means that three triggers are
     created for each unique hash index.) However, an _ordered_ index
     requires only a single trigger object. Backups also use three
     trigger objects for each normal table in the cluster.

     This parameter sets the maximum number of trigger objects in the
     cluster.

     The default value is 768.

   * `MaxNoOfIndexes'

     This parameter is deprecated in MySQL 5.0; you should use
     `MaxNoOfOrderedIndexes' and `MaxNoOfUniqueHashIndexes' instead.

     This parameter is used only by unique hash indexes. There needs to
     be one record in this pool for each unique hash index defined in
     the cluster.

     The default value of this parameter is 128.

Boolean parameters

The behavior of data nodes is also affected by a set of `[ndbd]'
parameters taking on boolean values.  These parameters can each be
specified as `TRUE' by setting them equal to `1' or `Y', and as `FALSE'
by setting them equal to `0' or `N'.

   * `LockPagesInMainMemory'

     Options for lockpagesinmainmemory-ndbd      *Restart Type*       node            
                          *Permitted        
                          Values          
                          (>=             
                          5.0.0,          
                          <=              
                          5.0.35)*        
     *Type*               `boolean'        
     *Default*            `0'             
     *Range*              `0 ..           
                          1'              
                          *Permitted        
                          Values          
                          (>=             
                          5.0.36)*        
     *Type*               `numeric'        
     *Default*            `0'             
     *Range*              `0 ..           
                          2'              


     For a number of operating systems, including Solaris and Linux, it
     is possible to lock a process into memory and so avoid any
     swapping to disk. This can be used to help guarantee the cluster's
     real-time characteristics.

     Beginning with MySQL 5.0.36, this parameter takes one of the
     integer values `0', `1', or `2', which act as follows:

        * `0': Disables locking. This is the default value.

        * `1': Performs the lock after allocating memory for the
          process.

        * `2': Performs the lock before memory for the process is
          allocated.

     Previously, this parameter was a Boolean.  `0' or `false' was the
     default setting, and disabled locking. `1' or `true' enabled
     locking of the process after its memory was allocated.

     *Important*:

     Beginning with MySQL 5.0.36, it is no longer possible to use
     `true' or `false' for the value of this parameter; when upgrading
     from a previous version, you must change the value to `0', `1', or
     `2'.

     *Note*:

     To make use of this parameter, the data node process must be run
     as system root.

   * `StopOnError'

     Options for stoponerror-ndbd      *Restart Type*       node            
                          *Permitted        
                          Values          
                          *               
     *Type*               `boolean'        
     *Default*            `true'          
     *Range*              ` .. '          


     This parameter specifies whether an *Note `ndbd':
     mysql-cluster-programs-ndbd.  process should exit or perform an
     automatic restart when an error condition is encountered.

     This feature is enabled by default.

   * `Diskless'

     Options for diskless-ndbd      *Restart Type*       initial,        
                          system          
                          *Permitted        
                          Values          
                          *               
     *Type*               `boolean'        
     *Default*            `0'             
     *Range*              `0 ..           
                          1'              


     It is possible to specify MySQL Cluster tables as _diskless_,
     meaning that tables are not checkpointed to disk and that no
     logging occurs. Such tables exist only in main memory. A
     consequence of using diskless tables is that neither the tables
     nor the records in those tables survive a crash. However, when
     operating in diskless mode, it is possible to run *Note `ndbd':
     mysql-cluster-programs-ndbd. on a diskless computer.

     *Important*:

     This feature causes the _entire_ cluster to operate in diskless
     mode.

     When this feature is enabled, Cluster online backup is disabled.
     In addition, a partial start of the cluster is not possible.

     `Diskless' is disabled by default.

   * `RestartOnErrorInsert'

     Options for restartonerrorinsert-ndbd      *Restart Type*       node            
                          *Permitted        
                          Values          
                          *               
     *Type*               `numeric'        
     *Default*            `2'             
     *Range*              `0 ..           
                          4'              


     This feature is accessible only when building the debug version
     where it is possible to insert errors in the execution of
     individual blocks of code as part of testing.

     This feature is disabled by default.

*Controlling Timeouts, Intervals, and Disk Paging*

There are a number of `[ndbd]' parameters specifying timeouts and
intervals between various actions in Cluster data nodes. Most of the
timeout values are specified in milliseconds. Any exceptions to this
are mentioned where applicable.

   * `TimeBetweenWatchDogCheck'

     Options for timebetweenwatchdogcheck-ndbd      *Restart Type*       node            
                          *Permitted        
                          Values          
                          *               
     *Type*               `numeric'        
     *Default*            `6000'          
     *Range*              `70 ..          
                          4G'             


     To prevent the main thread from getting stuck in an endless loop
     at some point, a `watchdog' thread checks the main thread. This
     parameter specifies the number of milliseconds between checks. If
     the process remains in the same state after three checks, the
     watchdog thread terminates it.

     This parameter can easily be changed for purposes of
     experimentation or to adapt to local conditions. It can be
     specified on a per-node basis although there seems to be little
     reason for doing so.

     The default timeout is 4000 milliseconds (4 seconds).

   * `StartPartialTimeout'

     Options for startpartialtimeout-ndbd      *Restart Type*       node            
                          *Permitted        
                          Values          
                          *               
     *Type*               `numeric'        
     *Default*            `30000'         
     *Range*              `0 ..           
                          4G'             


     This parameter specifies how long the Cluster waits for all data
     nodes to come up before the cluster initialization routine is
     invoked. This timeout is used to avoid a partial Cluster startup
     whenever possible.

     This parameter is overridden when performing an initial start or
     initial restart of the cluster.

     The default value is 30000 milliseconds (30 seconds). 0 disables
     the timeout, in which case the cluster may start only if all nodes
     are available.

   * `StartPartitionedTimeout'

     Options for startpartitionedtimeout-ndbd      *Restart Type*       node            
                          *Permitted        
                          Values          
                          *               
     *Type*               `numeric'        
     *Default*            `60000'         
     *Range*              `0 ..           
                          4G'             


     If the cluster is ready to start after waiting for
     `StartPartialTimeout' milliseconds but is still possibly in a
     partitioned state, the cluster waits until this timeout has also
     passed. If `StartPartitionedTimeout' is set to 0, the cluster
     waits indefinitely.

     This parameter is overridden when performing an initial start or
     initial restart of the cluster.

     The default timeout is 60000 milliseconds (60 seconds).

   * `StartFailureTimeout'

     Options for startfailuretimeout-ndbd      *Restart Type*       node            
                          *Permitted        
                          Values          
                          *               
     *Type*               `numeric'        
     *Default*            `0'             
     *Range*              `0 ..           
                          4G'             


     If a data node has not completed its startup sequence within the
     time specified by this parameter, the node startup fails. Setting
     this parameter to 0 (the default value) means that no data node
     timeout is applied.

     For nonzero values, this parameter is measured in milliseconds.
     For data nodes containing extremely large amounts of data, this
     parameter should be increased. For example, in the case of a data
     node containing several gigabytes of data, a period as long as
     10-15 minutes (that is, 600000 to 1000000 milliseconds) might be
     required to perform a node restart.

   * `HeartbeatIntervalDbDb'

     Options for heartbeatintervaldbdb-ndbd      *Restart Type*       node            
                          *Permitted        
                          Values          
                          *               
     *Type*               `numeric'        
     *Default*            `1500'          
     *Range*              `10 ..          
                          4G'             


     One of the primary methods of discovering failed nodes is by the
     use of heartbeats. This parameter states how often heartbeat
     signals are sent and how often to expect to receive them. After
     missing three heartbeat intervals in a row, the node is declared
     dead. Thus, the maximum time for discovering a failure through the
     heartbeat mechanism is four times the heartbeat interval.

     The default heartbeat interval is 1500 milliseconds (1.5 seconds).
     This parameter must not be changed drastically and should not vary
     widely between nodes. If one node uses 5000 milliseconds and the
     node watching it uses 1000 milliseconds, obviously the node will
     be declared dead very quickly. This parameter can be changed
     during an online software upgrade, but only in small increments.

     See also *Note mysql-cluster-network-latency-issues::.

   * `HeartbeatIntervalDbApi'

     Options for heartbeatintervaldbapi-ndbd      *Restart Type*       node            
                          *Permitted        
                          Values          
                          *               
     *Type*               `numeric'        
     *Default*            `1500'          
     *Range*              `100            
                          .. 4G'          


     Each data node sends heartbeat signals to each MySQL server (SQL
     node) to ensure that it remains in contact. If a MySQL server
     fails to send a heartbeat in time it is declared `dead,' in which
     case all ongoing transactions are completed and all resources
     released. The SQL node cannot reconnect until all activities
     initiated by the previous MySQL instance have been completed. The
     three-heartbeat criteria for this determination are the same as
     described for `HeartbeatIntervalDbDb'.

     The default interval is 1500 milliseconds (1.5 seconds).  This
     interval can vary between individual data nodes because each data
     node watches the MySQL servers connected to it, independently of
     all other data nodes.

     For more information, see *Note
     mysql-cluster-network-latency-issues::.

   * `TimeBetweenLocalCheckpoints'

     Options for timebetweenlocalcheckpoints-ndbd      *Restart Type*       node            
                          *Permitted        
                          Values          
                          *               
     *Type*               `numeric'        
     *Default*            `20'            
     *Range*              `0 ..           
                          31'             


     This parameter is an exception in that it does not specify a time
     to wait before starting a new local checkpoint; rather, it is used
     to ensure that local checkpoints are not performed in a cluster
     where relatively few updates are taking place. In most clusters
     with high update rates, it is likely that a new local checkpoint
     is started immediately after the previous one has been completed.

     The size of all write operations executed since the start of the
     previous local checkpoints is added. This parameter is also
     exceptional in that it is specified as the base-2 logarithm of the
     number of 4-byte words, so that the default value 20 means 4MB (4 x
     2^20) of write operations, 21 would mean 8MB, and so on up to a
     maximum value of 31, which equates to 8GB of write operations.

     All the write operations in the cluster are added together.
     Setting `TimeBetweenLocalCheckpoints' to 6 or less means that
     local checkpoints will be executed continuously without pause,
     independent of the cluster's workload.

   * `TimeBetweenGlobalCheckpoints'

     Options for timebetweenglobalcheckpoints-ndbd      *Restart Type*       node            
                          *Permitted        
                          Values          
                          *               
     *Type*               `numeric'        
     *Default*            `2000'          
     *Range*              `10 ..          
                          32000'          


     When a transaction is committed, it is committed in main memory in
     all nodes on which the data is mirrored. However, transaction log
     records are not flushed to disk as part of the commit. The
     reasoning behind this behavior is that having the transaction
     safely committed on at least two autonomous host machines should
     meet reasonable standards for durability.

     It is also important to ensure that even the worst of cases--a
     complete crash of the cluster--is handled properly. To guarantee
     that this happens, all transactions taking place within a given
     interval are put into a global checkpoint, which can be thought of
     as a set of committed transactions that has been flushed to disk.
     In other words, as part of the commit process, a transaction is
     placed in a global checkpoint group. Later, this group's log
     records are flushed to disk, and then the entire group of
     transactions is safely committed to disk on all computers in the
     cluster.

     This parameter defines the interval between global checkpoints.
     The default is 2000 milliseconds.

   * `TimeBetweenInactiveTransactionAbortCheck'

     Options for timebetweeninactivetransactionabortcheck-ndbd      *Restart Type*       node            
                          *Permitted        
                          Values          
                          *               
     *Type*               `numeric'        
     *Default*            `1000'          
     *Range*              `1000           
                          .. 4G'          


     Timeout handling is performed by checking a timer on each
     transaction once for every interval specified by this parameter.
     Thus, if this parameter is set to 1000 milliseconds, every
     transaction will be checked for timing out once per second.

     The default value is 1000 milliseconds (1 second).

   *  `TransactionInactiveTimeout'

     Options for transactioninactivetimeout-ndbd      *Restart Type*       node            
                          *Permitted        
                          Values          
                          *               
     *Type*               `numeric'        
     *Default*            `4G'            
     *Range*              `0 ..           
                          4G'             


     This parameter states the maximum time that is permitted to lapse
     between operations in the same transaction before the transaction
     is aborted.

     The default for this parameter is `4G' (also the maximum). For a
     real-time database that needs to ensure that no transaction keeps
     locks for too long, this parameter should be set to a relatively
     small value. The unit is milliseconds.

   * `TransactionDeadlockDetectionTimeout'

     Options for transactiondeadlockdetectiontimeout-ndbd      *Restart Type*       node            
                          *Permitted        
                          Values          
                          *               
     *Type*               `numeric'        
     *Default*            `1200'          
     *Range*              `50 ..          
                          4G'             


     When a node executes a query involving a transaction, the node
     waits for the other nodes in the cluster to respond before
     continuing. A failure to respond can occur for any of the
     following reasons:

        * The node is `dead'

        * The operation has entered a lock queue

        * The node requested to perform the action could be heavily
          overloaded.

     This timeout parameter states how long the transaction coordinator
     waits for query execution by another node before aborting the
     transaction, and is important for both node failure handling and
     deadlock detection. In MySQL 5.0.20 and earlier versions, setting
     it too high could cause undesirable behavior in situations
     involving deadlocks and node failure. Beginning with MySQL 5.0.21,
     active transactions occurring during node failures are actively
     aborted by the MySQL Cluster Transaction Coordinator, and so high
     settings are no longer an issue with this parameter.

     The default timeout value is 1200 milliseconds (1.2 seconds). The
     effective minimum value is 100 milliseconds; it is possible to set
     it as low as 50 milliseconds, but any such value is treated as 100
     ms. (Bug #44099)

   * `NoOfDiskPagesToDiskAfterRestartTUP'

     Options for noofdiskpagestodiskafterrestarttup-ndbd      *Restart Type*       node            
                          *Permitted        
                          Values          
                          *               
     *Type*               `numeric'        
     *Default*            `40'            
     *Range*              `1 ..           
                          4G'             


     When executing a local checkpoint, the algorithm flushes all data
     pages to disk. Merely doing so as quickly as possible without any
     moderation is likely to impose excessive loads on processors,
     networks, and disks. To control the write speed, this parameter
     specifies how many pages per 100 milliseconds are to be written.
     In this context, a `page' is defined as 8KB. This parameter is
     specified in units of 80KB per second, so setting
     `NoOfDiskPagesToDiskAfterRestartTUP' to a value of `20' entails
     writing 1.6MB in data pages to disk each second during a local
     checkpoint. This value includes the writing of UNDO log records
     for data pages. That is, this parameter handles the limitation of
     writes from data memory. UNDO log records for index pages are
     handled by the parameter `NoOfDiskPagesToDiskAfterRestartACC'. (See
     the entry for `IndexMemory' for information about index pages.)

     In short, this parameter specifies how quickly to execute local
     checkpoints. It operates in conjunction with
     `NoOfFragmentLogFiles', `DataMemory', and `IndexMemory'.

     For more information about the interaction between these
     parameters and possible strategies for choosing appropriate values
     for them, see *Note mysql-cluster-config-lcp-params::.

     The default value is 40 (3.2MB of data pages per second).

   * `NoOfDiskPagesToDiskAfterRestartACC'

     Options for noofdiskpagestodiskafterrestartacc-ndbd      *Restart Type*       node            
                          *Permitted        
                          Values          
                          *               
     *Type*               `numeric'        
     *Default*            `20'            
     *Range*              `1 ..           
                          4G'             


     This parameter uses the same units as
     `NoOfDiskPagesToDiskAfterRestartTUP' and acts in a similar
     fashion, but limits the speed of writing index pages from index
     memory.

     The default value of this parameter is 20 (1.6MB of index memory
     pages per second).

   * `NoOfDiskPagesToDiskDuringRestartTUP'

     Options for noofdiskpagestodiskduringrestarttup-ndbd      *Restart Type*       node            
                          *Permitted        
                          Values          
                          *               
     *Type*               `numeric'        
     *Default*            `40'            
     *Range*              `1 ..           
                          4G'             


     This parameter is used in a fashion similar to
     `NoOfDiskPagesToDiskAfterRestartTUP' and
     `NoOfDiskPagesToDiskAfterRestartACC', only it does so with regard
     to local checkpoints executed in the node when a node is
     restarting. A local checkpoint is always performed as part of all
     node restarts. During a node restart it is possible to write to
     disk at a higher speed than at other times, because fewer
     activities are being performed in the node.

     This parameter covers pages written from data memory.

     The default value is 40 (3.2MB per second).

   * `NoOfDiskPagesToDiskDuringRestartACC'

     Options for noofdiskpagestodiskduringrestartacc-ndbd      *Restart Type*       node            
                          *Permitted        
                          Values          
                          *               
     *Type*               `numeric'        
     *Default*            `20'            
     *Range*              `1 ..           
                          4G'             


     Controls the number of index memory pages that can be written to
     disk during the local checkpoint phase of a node restart.

     As with `NoOfDiskPagesToDiskAfterRestartTUP' and
     `NoOfDiskPagesToDiskAfterRestartACC', values for this parameter
     are expressed in terms of 8KB pages written per 100 milliseconds
     (80KB/second).

     The default value is 20 (1.6MB per second).

   * `ArbitrationTimeout'

     Options for arbitrationtimeout-ndbd      *Restart Type*       node            
                          *Permitted        
                          Values          
                          *               
     *Type*               `numeric'        
     *Default*            `3000'          
     *Range*              `10 ..          
                          4G'             


     This parameter specifies how long data nodes wait for a response
     from the arbitrator to an arbitration message. If this is
     exceeded, the network is assumed to have split.

     The default value is 1000 milliseconds (1 second).

Buffering and logging

Several `[ndbd]' configuration parameters corresponding to former
compile-time parameters were introduced in MySQL 4.1.5. These enable
the advanced user to have more control over the resources used by node
processes and to adjust various buffer sizes at need.

These buffers are used as front ends to the file system when writing
log records to disk. If the node is running in diskless mode, these
parameters can be set to their minimum values without penalty due to
the fact that disk writes are `faked' by the *Note `NDB': mysql-cluster.
storage engine's file system abstraction layer.

   * `UndoIndexBuffer'

     Options for undoindexbuffer-ndbd      *Restart Type*       node            
                          *Permitted        
                          Values          
                          *               
     *Type*               `numeric'        
     *Default*            `2M'            
     *Range*              `1M ..          
                          4G'             


     The UNDO index buffer, whose size is set by this parameter, is
     used during local checkpoints. The *Note `NDB': mysql-cluster.
     storage engine uses a recovery scheme based on checkpoint
     consistency in conjunction with an operational REDO log. To
     produce a consistent checkpoint without blocking the entire system
     for writes, UNDO logging is done while performing the local
     checkpoint. UNDO logging is activated on a single table fragment
     at a time. This optimization is possible because tables are stored
     entirely in main memory.

     The UNDO index buffer is used for the updates on the primary key
     hash index. Inserts and deletes rearrange the hash index; the NDB
     storage engine writes UNDO log records that map all physical
     changes to an index page so that they can be undone at system
     restart. It also logs all active insert operations for each
     fragment at the start of a local checkpoint.

     Reads and updates set lock bits and update a header in the hash
     index entry. These changes are handled by the page-writing
     algorithm to ensure that these operations need no UNDO logging.

     This buffer is 2MB by default. The minimum value is 1MB, which is
     sufficient for most applications. For applications doing extremely
     large or numerous inserts and deletes together with large
     transactions and large primary keys, it may be necessary to
     increase the size of this buffer. If this buffer is too small, the
     NDB storage engine issues internal error code 677 (`Index UNDO
     buffers overloaded').

     *Important*:

     It is not safe to decrease the value of this parameter during a
     rolling restart.

   * `UndoDataBuffer'

     Options for undodatabuffer-ndbd      *Restart Type*       node            
                          *Permitted        
                          Values          
                          *               
     *Type*               `numeric'        
     *Default*            `16M'           
     *Range*              `1M ..          
                          4G'             


     This parameter sets the size of the UNDO data buffer, which
     performs a function similar to that of the UNDO index buffer,
     except the UNDO data buffer is used with regard to data memory
     rather than index memory. This buffer is used during the local
     checkpoint phase of a fragment for inserts, deletes, and updates.

     Because UNDO log entries tend to grow larger as more operations
     are logged, this buffer is also larger than its index memory
     counterpart, with a default value of 16MB.

     This amount of memory may be unnecessarily large for some
     applications. In such cases, it is possible to decrease this size
     to a minimum of 1MB.

     It is rarely necessary to increase the size of this buffer.  If
     there is such a need, it is a good idea to check whether the disks
     can actually handle the load caused by database update activity. A
     lack of sufficient disk space cannot be overcome by increasing the
     size of this buffer.

     If this buffer is too small and gets congested, the NDB storage
     engine issues internal error code 891 (`Data UNDO buffers
     overloaded').

     *Important*:

     It is not safe to decrease the value of this parameter during a
     rolling restart.

   * `RedoBuffer'

     Options for redobuffer-ndbd      *Restart Type*       node            
                          *Permitted        
                          Values          
                          *               
     *Type*               `numeric'        
     *Default*            `8M'            
     *Range*              `1M ..          
                          4G'             


     All update activities also need to be logged. The REDO log makes
     it possible to replay these updates whenever the system is
     restarted. The NDB recovery algorithm uses a `fuzzy' checkpoint of
     the data together with the UNDO log, and then applies the REDO log
     to play back all changes up to the restoration point.

     `RedoBuffer' sets the size of the buffer in which the REDO log is
     written, and is 8MB by default. The minimum value is 1MB.

     If this buffer is too small, the NDB storage engine issues error
     code 1221 (`REDO log buffers overloaded').

     *Important*:

     It is not safe to decrease the value of this parameter during a
     rolling restart.

Controlling log messages

In managing the cluster, it is very important to be able to control the
number of log messages sent for various event types to `stdout'. For
each event category, there are 16 possible event levels (numbered 0
through 15).  Setting event reporting for a given event category to
level 15 means all event reports in that category are sent to `stdout';
setting it to 0 means that there will be no event reports made in that
category.

By default, only the startup message is sent to `stdout', with the
remaining event reporting level defaults being set to 0. The reason for
this is that these messages are also sent to the management server's
cluster log.

An analogous set of levels can be set for the management client to
determine which event levels to record in the cluster log.

   * `LogLevelStartup'

     Options for loglevelstartup-ndbd      *Restart Type*       node            
                          *Permitted        
                          Values          
                          *               
     *Type*               `numeric'        
     *Default*            `1'             
     *Range*              `0 ..           
                          15'             


     The reporting level for events generated during startup of the
     process.

     The default level is 1.

   * `LogLevelShutdown'

     Options for loglevelshutdown-ndbd      *Restart Type*       node            
                          *Permitted        
                          Values          
                          *               
     *Type*               `numeric'        
     *Default*            `0'             
     *Range*              `0 ..           
                          15'             


     The reporting level for events generated as part of graceful
     shutdown of a node.

     The default level is 0.

   * `LogLevelStatistic'

     Options for loglevelstatistic-ndbd      *Restart Type*       node            
                          *Permitted        
                          Values          
                          *               
     *Type*               `numeric'        
     *Default*            `0'             
     *Range*              `0 ..           
                          15'             


     The reporting level for statistical events such as number of
     primary key reads, number of updates, number of inserts,
     information relating to buffer usage, and so on.

     The default level is 0.

   * `LogLevelCheckpoint'

     Options for loglevelcheckpoint-ndbd      *Restart Type*       initial,        
                          node            
                          *Permitted        
                          Values          
                          *               
     *Type*               `numeric'        
     *Default*            `0'             
     *Range*              `0 ..           
                          15'             


     The reporting level for events generated by local and global
     checkpoints.

     The default level is 0.

   * `LogLevelNodeRestart'

     Options for loglevelnoderestart-ndbd      *Restart Type*       node            
                          *Permitted        
                          Values          
                          *               
     *Type*               `numeric'        
     *Default*            `0'             
     *Range*              `0 ..           
                          15'             


     The reporting level for events generated during node restart.

     The default level is 0.

   * `LogLevelConnection'

     Options for loglevelconnection-ndbd      *Restart Type*       node            
                          *Permitted        
                          Values          
                          *               
     *Type*               `numeric'        
     *Default*            `0'             
     *Range*              `0 ..           
                          15'             


     The reporting level for events generated by connections between
     cluster nodes.

     The default level is 0.

   * `LogLevelError'

     Options for loglevelerror-ndbd      *Restart Type*       node            
                          *Permitted        
                          Values          
                          *               
     *Type*               `numeric'        
     *Default*            `0'             
     *Range*              `0 ..           
                          15'             


     The reporting level for events generated by errors and warnings by
     the cluster as a whole. These errors do not cause any node failure
     but are still considered worth reporting.

     The default level is 0.

   * `LogLevelCongestion'

     Options for loglevelcongestion-ndbd      *Restart Type*       node            
                          *Permitted        
                          Values          
                          (>=             
                          5.0.0)*         
     *Type*               `numeric'        
     *Default*            `0'             
     *Range*              `0 ..           
                          15'             


     The reporting level for events generated by congestion.  These
     errors do not cause node failure but are still considered worth
     reporting.

     The default level is 0.

   * `LogLevelInfo'

     Options for loglevelinfo-ndbd      *Restart Type*       node            
                          *Permitted        
                          Values          
                          *               
     *Type*               `numeric'        
     *Default*            `0'             
     *Range*              `0 ..           
                          15'             


     The reporting level for events generated for information about the
     general state of the cluster.

     The default level is 0.

Backup parameters

The `[ndbd]' parameters discussed in this section define memory buffers
set aside for execution of online backups.

   * `BackupDataBufferSize'

     Options for backupdatabuffersize-ndbd      *Restart Type*       node            
                          *Permitted        
                          Values          
                          *               
     *Type*               `numeric'        
     *Default*            `2M'            
     *Range*              `0 ..           
                          4G'             


     In creating a backup, there are two buffers used for sending data
     to the disk. The backup data buffer is used to fill in data
     recorded by scanning a node's tables. Once this buffer has been
     filled to the level specified as `BackupWriteSize' (see below),
     the pages are sent to disk. While flushing data to disk, the backup
     process can continue filling this buffer until it runs out of
     space. When this happens, the backup process pauses the scan and
     waits until some disk writes have completed freed up memory so
     that scanning may continue.

     The default value is 2MB.

   * `BackupLogBufferSize'

     Options for backuplogbuffersize-ndbd      *Restart Type*       node            
                          *Permitted        
                          Values          
                          *               
     *Type*               `numeric'        
     *Default*            `2M'            
     *Range*              `0 ..           
                          4G'             


     The backup log buffer fulfills a role similar to that played by
     the backup data buffer, except that it is used for generating a
     log of all table writes made during execution of the backup. The
     same principles apply for writing these pages as with the backup
     data buffer, except that when there is no more space in the backup
     log buffer, the backup fails.  For that reason, the size of the
     backup log buffer must be large enough to handle the load caused
     by write activities while the backup is being made. See *Note
     mysql-cluster-backup-configuration::.

     The default value for this parameter should be sufficient for most
     applications. In fact, it is more likely for a backup failure to
     be caused by insufficient disk write speed than it is for the
     backup log buffer to become full. If the disk subsystem is not
     configured for the write load caused by applications, the cluster
     is unlikely to be able to perform the desired operations.

     It is preferable to configure cluster nodes in such a manner that
     the processor becomes the bottleneck rather than the disks or the
     network connections.

     The default value is 2MB.

   * `BackupMemory'

     Options for backupmemory-ndbd      *Restart Type*       node            
                          *Permitted        
                          Values          
                          *               
     *Type*               `numeric'        
     *Default*            `4M'            
     *Range*              `0 ..           
                          4G'             


     This parameter is simply the sum of `BackupDataBufferSize' and
     `BackupLogBufferSize'.

     The default value is 2MB + 2MB = 4MB.

     *Important*:

     If `BackupDataBufferSize' and `BackupLogBufferSize' taken together
     exceed 4MB, then this parameter must be set explicitly in the
     `config.ini' file to their sum.

   * `BackupWriteSize'

     Options for backupwritesize-ndbd      *Restart Type*       node            
                          *Permitted        
                          Values          
                          *               
     *Type*               `numeric'        
     *Default*            `32K'           
     *Range*              `2K ..          
                          4G'             


     This parameter specifies the default size of messages written to
     disk by the backup log and backup data buffers.

     The default value is 32KB.

   * `BackupMaxWriteSize'

     Options for backupmaxwritesize-ndbd      *Restart Type*       node            
                          *Permitted        
                          Values          
                          *               
     *Type*               `numeric'        
     *Default*            `256K'          
     *Range*              `2K ..          
                          4G'             


     This parameter specifies the maximum size of messages written to
     disk by the backup log and backup data buffers.

     The default value is 256KB.

*Important*:

When specifying these parameters, the following relationships must hold
true. Otherwise, the data node will be unable to start.

   * `BackupDataBufferSize >= BackupWriteSize + 188KB'

   * `BackupLogBufferSize >= BackupWriteSize + 16KB'

   * `BackupMaxWriteSize >= BackupWriteSize'

*Note*:

To add new data nodes to a MySQL Cluster, it is necessary to shut down
the cluster completely, update the `config.ini' file, and then restart
the cluster (that is, you must perform a system restart). All data node
processes must be started with the `--initial' option.

Beginning with MySQL Cluster NDB 7.0, it is possible to add new data
node groups to a running cluster online; however, we do not plan to
implement this change in MySQL 5.0.


File: manual.info,  Node: mysql-cluster-api-definition,  Next: mysql-cluster-tcp-definition,  Prev: mysql-cluster-ndbd-definition,  Up: mysql-cluster-config-file

17.3.2.6 Defining SQL and Other API Nodes in a MySQL Cluster
............................................................

The `[mysqld]' and `[api]' sections in the `config.ini' file define the
behavior of the MySQL servers (SQL nodes) and other applications (API
nodes) used to access cluster data. None of the parameters shown is
required. If no computer or host name is provided, any host can use
this SQL or API node.

Generally speaking, a `[mysqld]' section is used to indicate a MySQL
server providing an SQL interface to the cluster, and an `[api]'
section is used for applications other than *Note `mysqld': mysqld.
processes accessing cluster data, but the two designations are actually
synonomous; you can, for instance, list parameters for a MySQL server
acting as an SQL node in an `[api]' section.

*Note*:

For a discussion of MySQL server options for MySQL Cluster, see *Note
mysql-cluster-program-options-mysqld::; for information about MySQL
server system variables relating to MySQL Cluster, see *Note
mysql-cluster-system-variables::.

   *  `Id'

     Options for id-api      *Deprecated*         5.1.51-ndb-7.1.9        
     *Restart Type*       node            
                          *Permitted        
                          Values          
                          *               
     *Type*               `numeric'        
     *Default*            `'              
     *Range*              `1 ..           
                          63'             


     The `Id' is an integer value used to identify the node in all
     cluster internal messages. It must be an integer in the range 1 to
     63 inclusive, and must be unique among all node IDs within the
     cluster.

     In MySQL 5.0.15 and later, `NodeId' is a synonym for this
     parameter, and is the preferred form. In MySQL Cluster NDB 6.2 and
     later, `Id' is deprecated in favor of `NodeId' for identifying SQL
     and other API nodes.

   *  `NodeId'

     Options for nodeid-api      *Version Introduced* 5.0.15          
     *Restart Type*       node            
                          *Permitted        
                          Values          
                          (>=             
                          5.0.15)*        
     *Type*               `numeric'        
     *Default*            `'              
     *Range*              `1 ..           
                          63'             


     Beginning with MySQL 5.0.15, `NodeId' is available as a synonym
     for `Id'.

     In MySQL Cluster NDB 6.2 and later, `Id' is deprecated in favor of
     `NodeId' for identifying SQL and API nodes.

   * `ExecuteOnComputer'

     Options for executeoncomputer-api      *Restart Type*       system          
                          *Permitted        
                          Values          
                          *               
     *Type*               `string'        
     *Default*            `'              
     *Range*              ` .. '          


     This refers to the `Id' set for one of the computers (hosts)
     defined in a `[computer]' section of the configuration file.

   * `HostName'

     Options for hostname-api      *Restart Type*       system          
                          *Permitted        
                          Values          
                          *               
     *Type*               `string'        
     *Default*            `'              
     *Range*              ` .. '          


     Specifying this parameter defines the hostname of the computer on
     which the SQL node (API node) is to reside. To specify a hostname,
     either this parameter or `ExecuteOnComputer' is required.

     If no `HostName' or `ExecuteOnComputer' is specified in a given
     `[mysql]' or `[api]' section of the `config.ini' file, then an SQL
     or API node may connect using the corresponding `slot' from any
     host which can establish a network connection to the management
     server host machine.  _This differs from the default behavior for
     data nodes, where `localhost' is assumed for `HostName' unless
     otherwise specified_.

   * `ArbitrationRank'

     Options for arbitrationrank-api      *Restart Type*       node            
                          *Permitted        
                          Values          
                          *               
     *Type*               `numeric'        
     *Default*            `0'             
     *Range*              `0 ..           
                          2'              


     This parameter defines which nodes can act as arbitrators.  Both
     MGM nodes and SQL nodes can be arbitrators. A value of 0 means
     that the given node is never used as an arbitrator, a value of 1
     gives the node high priority as an arbitrator, and a value of 2
     gives it low priority. A normal configuration uses the management
     server as arbitrator, setting its `ArbitrationRank' to 1 (the
     default for management nodes) and those for all SQL nodes to 0
     (the default for SQL nodes).

   * `ArbitrationDelay'

     Options for arbitrationdelay-api      *Restart Type*       node            
                          *Permitted        
                          Values          
                          *               
     *Type*               `numeric'        
     *Default*            `0'             
     *Range*              `0 ..           
                          4G'             


     Setting this parameter to any other value than 0 (the default)
     means that responses by the arbitrator to arbitration requests
     will be delayed by the stated number of milliseconds. It is
     usually not necessary to change this value.

   * `BatchByteSize'

     Options for batchbytesize-api      *Restart Type*       node            


     For queries that are translated into full table scans or range
     scans on indexes, it is important for best performance to fetch
     records in properly sized batches. It is possible to set the
     proper size both in terms of number of records (`BatchSize') and
     in terms of bytes (`BatchByteSize'). The actual batch size is
     limited by both parameters.

     The speed at which queries are performed can vary by more than 40%
     depending upon how this parameter is set. In future releases,
     MySQL Server will make educated guesses on how to set parameters
     relating to batch size, based on the query type.

     This parameter is measured in bytes and by default is equal to
     32KB.

   * `BatchSize'

     Options for batchsize-api      *Restart Type*       node            


     This parameter is measured in number of records and is by default
     set to 64. The maximum size is 992.

   * `MaxScanBatchSize'

     Options for maxscanbatchsize-api      *Restart Type*       node            
                          *Permitted        
                          Values          
                          *               
     *Type*               `numeric'        
     *Default*            `256K'          
     *Range*              `32K            
                          .. 16M'         


     The batch size is the size of each batch sent from each data node.
     Most scans are performed in parallel to protect the MySQL Server
     from receiving too much data from many nodes in parallel; this
     parameter sets a limit to the total batch size over all nodes.

     The default value of this parameter is set to 256KB. Its maximum
     size is 16MB.

You can obtain some information from a MySQL server running as a
Cluster SQL node using *Note `SHOW STATUS': show-status. in the `mysql'
client, as shown here:

     mysql> SHOW STATUS LIKE 'ndb%';
     +-----------------------------+---------------+
     | Variable_name               | Value         |
     +-----------------------------+---------------+
     | Ndb_cluster_node_id         | 5             |
     | Ndb_config_from_host        | 192.168.0.112 |
     | Ndb_config_from_port        | 1186          |
     | Ndb_number_of_storage_nodes | 4             |
     +-----------------------------+---------------+
     4 rows in set (0.02 sec)

For information about these Cluster system status variables, see *Note
server-status-variables::.

*Note*:

To add new SQL or API nodes to the configuration of a running MySQL
Cluster, it is necessary to perform a rolling restart of all cluster
nodes after adding new `[mysqld]' or `[api]' sections to the
`config.ini' file (or files, if you are using more than one management
server). This must be done before the new SQL or API nodes can connect
to the cluster.

It is _not_ necessary to perform any restart of the cluster if new SQL
or API nodes can employ previously unused API slots in the cluster
configuration to connect to the cluster.


File: manual.info,  Node: mysql-cluster-tcp-definition,  Next: mysql-cluster-tcp-definition-direct,  Prev: mysql-cluster-api-definition,  Up: mysql-cluster-config-file

17.3.2.7 MySQL Cluster TCP/IP Connections
.........................................

TCP/IP is the default transport mechanism for all connections between
nodes in a MySQL Cluster. Normally it is not necessary to define TCP/IP
connections; MySQL Cluster automatically sets up such connections for
all data nodes, management nodes, and SQL or API nodes.

*Note*:

For an exception to this rule, see *Note
mysql-cluster-tcp-definition-direct::.

To override the default connection parameters, it is necessary to
define a connection using one or more `[tcp]' sections in the
`config.ini' file. Each `[tcp]' section explicitly defines a TCP/IP
connection between two MySQL Cluster nodes, and must contain at a
minimum the parameters `NodeId1' and `NodeId2', as well as any
connection parameters to override.

It is also possible to change the default values for these parameters
by setting them in the `[tcp default]' section.

*Important*:

Any `[tcp]' sections in the `config.ini' file should be listed _last_,
following all other sections in the file. However, this is not required
for a `[tcp default]' section. This requirement is a known issue with
the way in which the `config.ini' file is read by the MySQL Cluster
management server.

Connection parameters which can be set in `[tcp]' and `[tcp default]'
sections of the `config.ini' file are listed here:

   * `NodeId1'

     Options for nodeid1-tcp      *Restart Type*       node            
                          *Permitted        
                          Values          
                          *               
     *Type*               `numeric'        
     *Default*            `'              
     *Range*              ` .. '          


     `NodeId2'

     Options for nodeid2-tcp      *Restart Type*       node            
                          *Permitted        
                          Values          
                          *               
     *Type*               `numeric'        
     *Default*            `'              
     *Range*              ` .. '          


     To identify a connection between two nodes it is necessary to
     provide their node IDs in the `[tcp]' section of the configuration
     file. These are the same unique `Id' values for each of these
     nodes as described in *Note mysql-cluster-api-definition::.

   * `HostName1'

     Options for hostname1-tcp      *Restart Type*       node            
                          *Permitted        
                          Values          
                          *               
     *Type*               `string'        
     *Default*            `'              
     *Range*              ` .. '          


     `HostName2'

     Options for hostname2-tcp      *Restart Type*       node            
                          *Permitted        
                          Values          
                          *               
     *Type*               `string'        
     *Default*            `'              
     *Range*              ` .. '          


     The `HostName1' and `HostName2' parameters can be used to specify
     specific network interfaces to be used for a given TCP connection
     between two nodes. The values used for these parameters can be
     hostnames or IP addresses.

   * `SendBufferMemory'

     Options for sendbuffermemory-tcp      *Restart Type*       node            
                          *Permitted        
                          Values          
                          *               
     *Type*               `numeric'        
     *Default*            `256K'          
     *Range*              `64K            
                          .. 4G'          


     TCP transporters use a buffer to store all messages before
     performing the send call to the operating system. When this buffer
     reaches 64KB its contents are sent; these are also sent when a
     round of messages have been executed. To handle temporary overload
     situations it is also possible to define a bigger send buffer.

     The default size of the send buffer is 256 KB; 2MB is recommended
     in most situations in which it is necessary to set this parameter.
     The minimum size is 64 KB; the theoretical maximum is 4 GB.

   * `SendSignalId'

     Options for sendsignalid-tcp      *Restart Type*       node            
                          *Permitted        
                          Values          
                          *               
     *Type*               `boolean'        
     *Default*            `false          
                          (debug          
                          builds:         
                          true)'          
     *Range*              ` .. '          


     To be able to retrace a distributed message datagram, it is
     necessary to identify each message. When this parameter is set to
     `Y', message IDs are transported over the network. This feature is
     disabled by default in production builds, and enabled in `-debug'
     builds.

   * `Checksum'

     Options for checksum-tcp      *Restart Type*       node            
                          *Permitted        
                          Values          
                          *               
     *Type*               `boolean'        
     *Default*            `false'         
     *Range*              ` .. '          


     This parameter is a boolean parameter (enabled by setting it to
     `Y' or `1', disabled by setting it to `N' or `0').  It is disabled
     by default. When it is enabled, checksums for all messages are
     calculated before they placed in the send buffer. This feature
     ensures that messages are not corrupted while waiting in the send
     buffer, or by the transport mechanism.

   * `PortNumber' (_OBSOLETE_)

     This formerly specified the port number to be used for listening
     for connections from other nodes. This parameter should no longer
     be used.

   * `ReceiveBufferMemory'

     Options for receivebuffermemory-tcp      *Restart Type*       node            
                          *Permitted        
                          Values          
                          *               
     *Type*               `numeric'        
     *Default*            `64K'           
     *Range*              `16K            
                          .. 4G'          


     Specifies the size of the buffer used when receiving data from the
     TCP/IP socket.

     The default value of this parameter from its of 64 KB; 1M is
     recommended in most situations where the size of the receive
     buffer needs to be set. The minimum possible value is 16K;
     theoretical maximum is 4G.


File: manual.info,  Node: mysql-cluster-tcp-definition-direct,  Next: mysql-cluster-shm-definition,  Prev: mysql-cluster-tcp-definition,  Up: mysql-cluster-config-file

17.3.2.8 MySQL Cluster TCP/IP Connections Using Direct Connections
..................................................................

Setting up a cluster using direct connections between data nodes
requires specifying explicitly the crossover IP addresses of the data
nodes so connected in the `[tcp]' section of the cluster `config.ini'
file.

In the following example, we envision a cluster with at least four
hosts, one each for a management server, an SQL node, and two data
nodes. The cluster as a whole resides on the `172.23.72.*' subnet of a
LAN. In addition to the usual network connections, the two data nodes
are connected directly using a standard crossover cable, and
communicate with one another directly using IP addresses in the
`1.1.0.*' address range as shown:

     # Management Server
     [ndb_mgmd]
     Id=1
     HostName=172.23.72.20

     # SQL Node
     [mysqld]
     Id=2
     HostName=172.23.72.21

     # Data Nodes
     [ndbd]
     Id=3
     HostName=172.23.72.22

     [ndbd]
     Id=4
     HostName=172.23.72.23

     # TCP/IP Connections
     [tcp]
     NodeId1=3
     NodeId2=4
     HostName1=1.1.0.1
     HostName2=1.1.0.2

The `HostName1' and `HostName2' parameters are used only when
specifying direct TCP connections.

The use of direct TCP connections between data nodes can improve the
cluster's overall efficiency by enabling the data nodes to bypass an
Ethernet device such as a switch, hub, or router, thus cutting down on
the cluster's latency. It is important to note that to take the best
advantage of direct connections in this fashion with more than two data
nodes, you must have a direct connection between each data node and
every other data node in the same node group.


File: manual.info,  Node: mysql-cluster-shm-definition,  Next: mysql-cluster-sci-definition,  Prev: mysql-cluster-tcp-definition-direct,  Up: mysql-cluster-config-file

17.3.2.9 MySQL Cluster Shared-Memory Connections
................................................

MySQL Cluster attempts to use the shared memory transporter and
configure it automatically where possible. (In very early versions of
MySQL Cluster, shared memory segments functioned only when the server
binary was built using `--with-ndb-shm'.) `[shm]' sections in the
`config.ini' file explicitly define shared-memory connections between
nodes in the cluster.  When explicitly defining shared memory as the
connection method, it is necessary to define at least `NodeId1',
`NodeId2' and `ShmKey'. All other parameters have default values that
should work well in most cases.

*Important*:

_SHM functionality is considered experimental only_. It is not
officially supported in any current MySQL Cluster release, and testing
results indicate that SHM performance is not appreciably greater than
when using TCP/IP for the transporter.

For these reasons, you must determine for yourself or by using our free
resources (forums, mailing lists) whether SHM can be made to work
correctly in your specific case.

   * `NodeId1'

     Options for nodeid1-shm      *Restart Type*       node            
                          *Permitted        
                          Values          
                          *               
     *Type*               `numeric'        
     *Default*            `'              
     *Range*              ` .. '          


     `NodeId2'

     Options for nodeid2-shm      *Restart Type*       node            
                          *Permitted        
                          Values          
                          *               
     *Type*               `numeric'        
     *Default*            `'              
     *Range*              ` .. '          


     To identify a connection between two nodes it is necessary to
     provide node identifiers for each of them, as `NodeId1' and
     `NodeId2'.

   * `HostName1'

     Options for hostname1-shm      *Restart Type*       node            
                          *Permitted        
                          Values          
                          *               
     *Type*               `string'        
     *Default*            `'              
     *Range*              ` .. '          


     `HostName2'

     Options for hostname2-shm      *Restart Type*       node            
                          *Permitted        
                          Values          
                          *               
     *Type*               `string'        
     *Default*            `'              
     *Range*              ` .. '          


     The `HostName1' and `HostName2' parameters can be used to specify
     specific network interfaces to be used for a given SHM connection
     between two nodes. The values used for these parameters can be
     hostnames or IP addresses.

   * `ShmKey'

     Options for shmkey-shm      *Restart Type*       node            
                          *Permitted        
                          Values          
                          *               
     *Type*               `numeric'        
     *Default*            `'              
     *Range*              `0 ..           
                          4G'             


     When setting up shared memory segments, a node ID, expressed as an
     integer, is used to identify uniquely the shared memory segment to
     use for the communication. There is no default value.

   * `ShmSize'

     Options for shmsize-shm      *Restart Type*       node            
                          *Permitted        
                          Values          
                          *               
     *Type*               `numeric'        
     *Default*            `1M'            
     *Range*              `64K            
                          .. 4G'          


     Each SHM connection has a shared memory segment where messages
     between nodes are placed by the sender and read by the reader. The
     size of this segment is defined by `ShmSize'. The default value is
     1MB.

   * `SendSignalId'

     Options for sendsignalid-shm      *Restart Type*       node            
                          *Permitted        
                          Values          
                          *               
     *Type*               `boolean'        
     *Default*            `false'         
     *Range*              ` .. '          


     To retrace the path of a distributed message, it is necessary to
     provide each message with a unique identifier.  Setting this
     parameter to `Y' causes these message IDs to be transported over
     the network as well. This feature is disabled by default in
     production builds, and enabled in `-debug' builds.

   * `Checksum'

     Options for checksum-shm      *Restart Type*       node            
                          *Permitted        
                          Values          
                          *               
     *Type*               `boolean'        
     *Default*            `true'          
     *Range*              ` .. '          


     This parameter is a boolean (`Y'/`N') parameter which is disabled
     by default. When it is enabled, checksums for all messages are
     calculated before being placed in the send buffer.

     This feature prevents messages from being corrupted while waiting
     in the send buffer. It also serves as a check against data being
     corrupted during transport.

   * `SigNum'

     Options for signum-shm      *Restart Type*       node            
                          *Permitted        
                          Values          
                          *               
     *Type*               `numeric'        
     *Default*            `'              
     *Range*              `0 ..           
                          4G'             


     When using the shared memory transporter, a process sends an
     operating system signal to the other process when there is new
     data available in the shared memory. Should that signal conflict
     with with an existing signal, this parameter can be used to change
     it. This is a possibility when using SHM due to the fact that
     different operating systems use different signal numbers.

     The default value of `SigNum' is 0; therefore, it must be set to
     avoid errors in the cluster log when using the shared memory
     transporter. Typically, this parameter is set to 10 in the `[shm
     default]' section of the `config.ini' file.


File: manual.info,  Node: mysql-cluster-sci-definition,  Next: mysql-cluster-config-lcp-params,  Prev: mysql-cluster-shm-definition,  Up: mysql-cluster-config-file

17.3.2.10 SCI Transport Connections in MySQL Cluster
....................................................

`[sci]' sections in the `config.ini' file explicitly define SCI
(Scalable Coherent Interface) connections between cluster nodes.  Using
SCI transporters in MySQL Cluster is supported only when the MySQL
binaries are built using `--with-ndb-sci=/YOUR/PATH/TO/SCI'.  The PATH
should point to a directory that contains at a minimum `lib' and
`include' directories containing SISCI libraries and header files. (See
*Note mysql-cluster-interconnects:: for more information about SCI.)

In addition, SCI requires specialized hardware.

It is strongly recommended to use SCI Transporters only for
communication between *Note `ndbd': mysql-cluster-programs-ndbd.
processes. Note also that using SCI Transporters means that the *Note
`ndbd': mysql-cluster-programs-ndbd. processes never sleep. For this
reason, SCI Transporters should be used only on machines having at least
two CPUs dedicated for use by *Note `ndbd':
mysql-cluster-programs-ndbd. processes.  There should be at least one
CPU per *Note `ndbd': mysql-cluster-programs-ndbd.  process, with at
least one CPU left in reserve to handle operating system activities.

   * `NodeId1'

     Options for nodeid1-sci      *Restart Type*       node            
                          *Permitted        
                          Values          
                          *               
     *Type*               `numeric'        
     *Default*            `'              
     *Range*              ` .. '          


     `NodeId2'

     Options for nodeid2-sci      *Restart Type*       node            
                          *Permitted        
                          Values          
                          *               
     *Type*               `numeric'        
     *Default*            `'              
     *Range*              ` .. '          


     To identify a connection between two nodes it is necessary to
     provide node identifiers for each of them, as `NodeId1' and
     `NodeId2'.

   * `Host1SciId0'

     Options for host1sciid0-sci      *Restart Type*       node            
                          *Permitted        
                          Values          
                          *               
     *Type*               `numeric'        
     *Default*            `'              
     *Range*              `0 ..           
                          4G'             


     This identifies the SCI node ID on the first Cluster node
     (identified by `NodeId1').

   *  `Host1SciId1'

     Options for host1sciid1-sci      *Restart Type*       node            
                          *Permitted        
                          Values          
                          *               
     *Type*               `numeric'        
     *Default*            `0'             
     *Range*              `0 ..           
                          4G'             


     It is possible to set up SCI Transporters for failover between two
     SCI cards which then should use separate networks between the
     nodes. This identifies the node ID and the second SCI card to be
     used on the first node.

   *  `Host2SciId0'

     Options for host2sciid0-sci      *Restart Type*       node            
                          *Permitted        
                          Values          
                          *               
     *Type*               `numeric'        
     *Default*            `'              
     *Range*              `0 ..           
                          4G'             


     This identifies the SCI node ID on the second Cluster node
     (identified by `NodeId2').

   *  `Host2SciId1'

     Options for host2sciid1-sci      *Restart Type*       node            
                          *Permitted        
                          Values          
                          *               
     *Type*               `numeric'        
     *Default*            `0'             
     *Range*              `0 ..           
                          4G'             


     When using two SCI cards to provide failover, this parameter
     identifies the second SCI card to be used on the second node.

   * `HostName1'

     Options for hostname1-sci      *Restart Type*       node            
                          *Permitted        
                          Values          
                          *               
     *Type*               `string'        
     *Default*            `'              
     *Range*              ` .. '          


     `HostName2'

     Options for hostname2-sci      *Restart Type*       node            
                          *Permitted        
                          Values          
                          *               
     *Type*               `string'        
     *Default*            `'              
     *Range*              ` .. '          


     The `HostName1' and `HostName2' parameters can be used to specify
     specific network interfaces to be used for a given SCI connection
     between two nodes. The values used for these parameters can be
     hostnames or IP addresses.

   * `SharedBufferSize'

     Options for sharedbuffersize-sci      *Restart Type*       node            
                          *Permitted        
                          Values          
                          *               
     *Type*               `numeric'        
     *Default*            `10M'           
     *Range*              `64K            
                          .. 4G'          


     Each SCI transporter has a shared memory segment used for
     communication between the two nodes. Setting the size of this
     segment to the default value of 1MB should be sufficient for most
     applications. Using a smaller value can lead to problems when
     performing many parallel inserts; if the shared buffer is too
     small, this can also result in a crash of the *Note `ndbd':
     mysql-cluster-programs-ndbd. process.

   * `SendLimit'

     Options for sendlimit-sci      *Restart Type*       node            
                          *Permitted        
                          Values          
                          *               
     *Type*               `numeric'        
     *Default*            `8K'            
     *Range*              `128            
                          .. 32K'         


     A small buffer in front of the SCI media stores messages before
     transmitting them over the SCI network. By default, this is set to
     8KB. Our benchmarks show that performance is best at 64KB but 16KB
     reaches within a few percent of this, and there was little if any
     advantage to increasing it beyond 8KB.

   * `SendSignalId'

     Options for sendsignalid-sci      *Restart Type*       node            
                          *Permitted        
                          Values          
                          *               
     *Type*               `boolean'        
     *Default*            `true'          
     *Range*              ` .. '          


     To trace a distributed message it is necessary to identify each
     message uniquely. When this parameter is set to `Y', message IDs
     are transported over the network. This feature is disabled by
     default in production builds, and enabled in `-debug' builds.

   * `Checksum'

     Options for checksum-sci      *Restart Type*       node            
                          *Permitted        
                          Values          
                          *               
     *Type*               `boolean'        
     *Default*            `false'         
     *Range*              ` .. '          


     This parameter is a boolean value, and is disabled by default.
     When `Checksum' is enabled, checksums are calculated for all
     messages before they are placed in the send buffer. This feature
     prevents messages from being corrupted while waiting in the send
     buffer. It also serves as a check against data being corrupted
     during transport.


File: manual.info,  Node: mysql-cluster-config-lcp-params,  Prev: mysql-cluster-sci-definition,  Up: mysql-cluster-config-file

17.3.2.11 Configuring MySQL Cluster Parameters for Local Checkpoints
....................................................................

The parameters discussed in Logging and Checkpointing and in Data
Memory, Index Memory, and String Memory that are used to configure
local checkpoints for a MySQL Cluster do not exist in isolation, but
rather are very much interdepedent on each other.  In this section, we
illustrate how these parameters--including `DataMemory', `IndexMemory',
`NoOfDiskPagesToDiskAfterRestartTUP',
`NoOfDiskPagesToDiskAfterRestartACC', and
`NoOfFragmentLogFiles'--relate to one another in a working Cluster.

In this example, we assume that our application performs the following
numbers of types of operations per hour:

   * 50000 selects

   * 15000 inserts

   * 15000 updates

   * 15000 deletes

We also make the following assumptions about the data used in the
application:

   * We are working with a single table having 40 columns.

   * Each column can hold up to 32 bytes of data.

   * A typical *Note `UPDATE': update. run by the application affects
     the values of 5 columns.

   * No `NULL' values are inserted by the application.

A good starting point is to determine the amount of time that should
elapse between local checkpoints (LCPs). It is worth noting that, in
the event of a system restart, it takes 40-60 percent of this interval
to execute the REDO log--for example, if the time between LCPs is 5
minutes (300 seconds), then it should take 2 to 3 minutes (120 to 180
seconds) for the REDO log to be read.

The maximum amount of data per node can be assumed to be the size of
the `DataMemory' parameter. In this example, we assume that this is 2
GB. The `NoOfDiskPagesToDiskAfterRestartTUP' parameter represents the
amount of data to be checkpointed per unit time--however, this
parameter is actually expressed as the number of 8K memory pages to be
checkpointed per 100 milliseconds. 2 GB per 300 seconds is
approximately 6.8 MB per second, or 700 KB per 100 milliseconds, which
works out to roughly 85 pages per 100 milliseconds.

Similarly, we can calculate `NoOfDiskPagesToDiskAfterRestartACC' in
terms of the time for local checkpoints and the amount of memory
required for indexes--that is, the `IndexMemory'. Assuming that we
permit 512 MB for indexes, this works out to approximately 20 8-KB
pages per 100 milliseconds for this parameter.

Next, we need to determine the number of REDO log files required--that
is, fragment log files--the corresponding parameter being
`NoOfFragmentLogFiles'. We need to make sure that there are sufficient
REDO log files for keeping records for at least 3 local checkpoints. In
a production setting, there are always uncertainties--for instance, we
cannot be sure that disks always operate at top speed or with maximum
throughput.  For this reason, it is best to err on the side of caution,
so we double our requirement and calculate a number of fragment log
files which should be enough to keep records covering 6 local
checkpoints.

It is also important to remember that the disk also handles writes to
the REDO log and UNDO log, so if you find that the amount of data being
written to disk as determined by the values of
`NoOfDiskPagesToDiskAfterRestartACC' and
`NoOfDiskPagesToDiskAfterRestartTUP' is approaching the amount of disk
bandwidth available, you may wish to increase the time between local
checkpoints.

Given 5 minutes (300 seconds) per local checkpoint, this means that we
need to support writing log records at maximum speed for 6 * 300 = 1800
seconds. The size of a REDO log record is 72 bytes plus 4 bytes per
updated column value plus the maximum size of the updated column, and
there is one REDO log record for each table record updated in a
transaction, on each node where the data reside. Using the numbers of
operations set out previously in this section, we derive the following:

   * 50000 select operations per hour yields 0 log records (and thus 0
     bytes), since *Note `SELECT': select.  statements are not recorded
     in the REDO log.

   * 15000 *Note `DELETE': delete. statements per hour is approximately
     5 delete operations per second. (Since we wish to be conservative
     in our estimate, we round up here and in the following
     calculations.) No columns are updated by deletes, so these
     statements consume only 5 operations * 72 bytes per operation =
     360 bytes per second.

   * 15000 *Note `UPDATE': update. statements per hour is roughly the
     same as 5 updates per second. Each update uses 72 bytes, plus 4
     bytes per column * 5 columns updated, plus 32 bytes per column * 5
     columns--this works out to 72 + 20 + 160 = 252 bytes per
     operation, and multiplying this by 5 operation per second yields
     1260 bytes per second.

   * 15000 *Note `INSERT': insert. statements per hour is equivalent to
     5 insert operations per second. Each insert requires REDO log
     space of 72 bytes, plus 4 bytes per record * 40 columns, plus 32
     bytes per column * 40 columns, which is 72 + 160 + 1280 = 1512
     bytes per operation. This times 5 operations per second yields
     7560 bytes per second.

So the total number of REDO log bytes being written per second is
approximately 0 + 360 + 1260 + 7560 = 9180 bytes. Multiplied by 1800
seconds, this yields 16524000 bytes required for REDO logging, or
approximately 15.75 MB. The unit used for `NoOfFragmentLogFiles'
represents a set of 4 16-MB log files--that is, 64 MB. Thus, the
minimum value (3) for this parameter is sufficient for the scenario
envisioned in this example, since 3 times 64 = 192 MB, or about 12 times
what is required; the default value of 8 (or 512 MB) is more than ample
in this case.

A copy of each altered table record is kept in the UNDO log. In the
scenario discussed above, the UNDO log would not require any more space
than what is provided by the default seetings.  However, given the size
of disks, it is sensible to allocate at least 1 GB for it.


File: manual.info,  Node: mysql-cluster-params-overview,  Next: mysql-cluster-options-variables,  Prev: mysql-cluster-config-file,  Up: mysql-cluster-configuration

17.3.3 Overview of MySQL Cluster Configuration Parameters
---------------------------------------------------------

* Menu:

* mysql-cluster-params-ndbd::    MySQL Cluster Data Node Configuration Parameters
* mysql-cluster-params-mgmd::    MySQL Cluster Management Node Configuration Parameters
* mysql-cluster-params-api::     MySQL Cluster SQL Node and API Node Configuration Parameters
* mysql-cluster-params-other::   Other MySQL Cluster Configuration Parameters

The next four sections provide summary tables of MySQL Cluster
configuration parameters used in the `config.ini' file to govern the
cluster's functioning. Each table lists the parameters for one of the
Cluster node process types (*Note `ndbd': mysql-cluster-programs-ndbd,
*Note `ndb_mgmd': mysql-cluster-programs-ndb-mgmd, and *Note `mysqld':
mysqld.), and includes the parameter's type as well as its default,
mimimum, and maximum values as applicable.

These tables also indicate what type of restart is required (node
restart or system restart)--and whether the restart must be done with
`--initial'--to change the value of a given configuration parameter.

When performing a node restart or an initial node restart, all of the
cluster's data nodes must be restarted in turn (also referred to as a
_rolling restart_). It is possible to update cluster configuration
parameters marked as `node' online--that is, without shutting down the
cluster--in this fashion. An initial node restart requires restarting
each *Note `ndbd': mysql-cluster-programs-ndbd. process with the
`--initial' option.

A system restart requires a complete shutdown and restart of the entire
cluster. An initial system restart requires taking a backup of the
cluster, wiping the cluster file system after shutdown, and then
restoring from the backup following the restart.

In any cluster restart, all of the cluster's management servers must be
restarted for them to read the updated configuration parameter values.

*Important*:

Values for numeric cluster parameters can generally be increased
without any problems, although it is advisable to do so progressively,
making such adjustments in relatively small increments. Many of these
can be increased online, using a rolling restart.

However, decreasing the values of such parameters--whether this is done
using a node restart, node initial restart, or even a complete system
restart of the cluster--is not to be undertaken lightly; it is
recommended that you do so only after careful planning and testing.
This is especially true with regard to those parameters that relate to
memory usage and disk space, such as `MaxNoOfTables',
`MaxNoOfOrderedIndexes', and `MaxNoOfUniqueHashIndexes'. In addition,
it is the generally the case that configuration parameters relating to
memory and disk usage can be raised using a simple node restart, but
they require an initial node restart to be lowered.

Because some of these parameters can be used for configuring more than
one type of cluster node, they may appear in more than one of the
tables.

*Note*:

`4294967039'--which often appears as a maximum value in these
tables--is defined in the *Note `NDBCLUSTER': mysql-cluster. sources as
`MAX_INT_RNIL' and is equal to `0xFFFFFEFF', or `2^32 - 2^8 - 1'.


File: manual.info,  Node: mysql-cluster-params-ndbd,  Next: mysql-cluster-params-mgmd,  Prev: mysql-cluster-params-overview,  Up: mysql-cluster-params-overview

17.3.3.1 MySQL Cluster Data Node Configuration Parameters
.........................................................

The summary table in this section provides information about parameters
used in the `[ndbd]' or `[ndbd default]' sections of a `config.ini'
file for configuring MySQL Cluster data nodes. For detailed
descriptions and other additional information about each of these
parameters, see *Note mysql-cluster-ndbd-definition::.

Restart types

Changes in MySQL Cluster configuration parameters do not take effect
until the cluster is restarted. The type of restart required to change
a given parameter is indicated in the summary table as follows:

   * `N'--Node restart: The parameter can be updated using a rolling
     restart (see *Note mysql-cluster-rolling-restart::).

   * `S'--System restart: The cluster must be shut down completely,
     then restarted, to effect a change in this parameter.

   * `I'--Initial restart: Data nodes must be restarted using the
     `--initial' option.

For more information about restart types, see *Note
mysql-cluster-params-overview::.

*Data Node Configuration Parameters*

Name           Type/Units     Default    Min Value  Max Value  Restart
                                                               Type
ArbitrationTimeoutmilliseconds   3000       10         4G         N
BackupDataBufferSizebytes          2M                    4G         N
BackupDataDir  path           FileSystemPath                      IN
BackupLogBufferSizebytes          2M                    4G         N
BackupMaxWriteSizebytes          256K       2K         4G         N
BackupMemory   bytes          4M                    4G         N
BackupWriteSizebytes          32K        2K         4G         N
BatchSizePerLocalScaninteger        64         1          992        N
DataDir        path           .                                IN
DataMemory     bytes          80M        1M         1024G      N
Diskless       true|false                           1          IS
               (1|0)                                           
ExecuteOnComputername                                            S
HeartbeatIntervalDbApimilliseconds   1500       100        4G         N
HeartbeatIntervalDbDbmilliseconds   1500       10         4G         N
HostName       name or IP     localhost                        S
               address                                         
Id             unsigned                  1          48         N
IndexMemory    bytes          18M        1M         1T         N
LockPagesInMainMemorytrue|false                           1          N
               (1|0)                                           
LogLevelCheckpointlog level                            15         IN
LogLevelCongestionlevelr                               15         N
LogLevelConnectioninteger                              15         N
LogLevelError  integer                              15         N
LogLevelInfo   integer                              15         N
LogLevelNodeRestartinteger                              15         N
LogLevelShutdowninteger                              15         N
LogLevelStartupinteger        1                     15         N
LogLevelStatisticinteger                              15         N
LongMessageBufferbytes          1M         512K       4G         N
MaxNoOfAttributesinteger        1000       32         4G         N
MaxNoOfConcurrentIndexOperationsinteger        8K                    4G         N
MaxNoOfConcurrentOperationsinteger        32K        32         4G         N
MaxNoOfConcurrentScansinteger        256        2          500        N
MaxNoOfConcurrentTransactionsinteger        4096       32         4G         S
MaxNoOfFiredTriggersinteger        4000                  4G         N
MaxNoOfLocalOperationsinteger        UNDEFINED  32         4G         N
MaxNoOfLocalScansinteger        UNDEFINED  32         4G         N
MaxNoOfOpenFiles                                                N
MaxNoOfOrderedIndexesinteger        128                   4G         N
MaxNoOfSavedMessagesinteger        25                    4G         N
MaxNoOfTables  integer        128        8          20320      N
MaxNoOfTriggersinteger        768                   4G         N
MaxNoOfUniqueHashIndexesinteger        64                    4G         N
NodeId         unsigned                  1          48         N
NoOfDiskPagesToDiskAfterRestartACC8K pages/100   20         1          4G         N
               milliseconds                                    
NoOfDiskPagesToDiskAfterRestartTUP8K pages/100   40         1          4G         N
               milliseconds                                    
NoOfDiskPagesToDiskDuringRestartACC8K pages/100   20         1          4G         N
               milliseconds                                    
NoOfDiskPagesToDiskDuringRestartTUP8K pages/100   40         1          4G         N
               milliseconds                                    
NoOfFragmentLogFilesinteger        8          3          4G         IN
NoOfReplicas   integer        None       1          4          IS
RedoBuffer     bytes          8M         1M         4G         N
RestartOnErrorInserterror code     2                     4          N
ServerPort     unsigned                  1          64K        N
StartFailureTimeoutmilliseconds                         4G         N
StartPartialTimeoutmilliseconds   30000                 4G         N
StartPartitionedTimeoutmilliseconds   60000                 4G         N
StopOnError    true|false     true                             N
               (1|0)                                           
StringMemory   % or bytes                           4G         S
TimeBetweenGlobalCheckpointsmilliseconds   2000       10         32000      N
TimeBetweenInactiveTransactionAbortCheckmilliseconds   1000       1000       4G         N
TimeBetweenLocalCheckpointsnumber of      20                    31         N
               4-byte words,                                   
               as a base-2                                     
               logarithm                                       
TimeBetweenWatchDogCheckmilliseconds   6000       70         4G         N
TransactionBufferMemorybytes          1M         1K         4G         N
TransactionDeadlockDetectionTimeoutmilliseconds   1200       50         4G         N
TransactionInactiveTimeoutmilliseconds   4G                    4G         N
UndoDataBuffer unsigned       16M        1M         4G         N
UndoIndexBufferunsigned       2M         1M         4G         N

*Note*:

To add new data nodes to a MySQL Cluster, it is necessary to shut down
the cluster completely, update the `config.ini' file, and then restart
the cluster, starting all data node processes using the `--initial'
option--that is, you must perform a system restart.

It is possible to add new data node groups to a running cluster online
using MySQL Cluster NDB 7.0 or later (see Adding MySQL Cluster Data
Nodes Online
(http://dev.mysql.com/doc/refman/5.1/en/mysql-cluster-online-add-node.html));
however, we do not plan to implement this change in MySQL 5.0.


File: manual.info,  Node: mysql-cluster-params-mgmd,  Next: mysql-cluster-params-api,  Prev: mysql-cluster-params-ndbd,  Up: mysql-cluster-params-overview

17.3.3.2 MySQL Cluster Management Node Configuration Parameters
...............................................................

The summary table in this section provides information about parameters
used in the `[ndb_mgmd]' or `[mgm]' sections of a `config.ini' file for
configuring MySQL Cluster management nodes. For detailed descriptions
and other additional information about each of these parameters, see
*Note mysql-cluster-mgm-definition::.

Restart types

Changes in MySQL Cluster configuration parameters do not take effect
until the cluster is restarted. The type of restart required to change
a given parameter is indicated in the summary table as follows:

   * `N'--Node restart: The parameter can be updated using a rolling
     restart (see *Note mysql-cluster-rolling-restart::).

   * `S'--System restart: The cluster must be shut down completely,
     then restarted, to effect a change in this parameter.

   * `I'--Initial restart: Data nodes must be restarted using the
     `--initial' option.

For more information about restart types, see *Note
mysql-cluster-params-overview::.

*Management Node Configuration Parameters*

Name           Type/Units     Default    Min Value  Max Value  Restart
                                                               Type
ArbitrationDelaymilliseconds                         4G         N
ArbitrationRank0-2            1                     2          N
DataDir        path           .                                N
ExecuteOnComputername                                            S
HostName       name or IP                                      S
               address                                         
Id             unsigned                  1          63         N
LogDestination {CONSOLE|SYSLOG|FILE}FILE:filename=ndb_nodeid_cluster.log,maxsize=1000000,maxfiles=6                      N
MaxNoOfSavedEventsunsigned       100                   4G         N
NodeId         unsigned                  1          63         N
PortNumber     unsigned       1186                  64K        N
PortNumberStatsunsigned                             64K        N

*Note*:

After making changes in a management node's configuration, it is
necessary to perform a rolling restart of the cluster for the new
configuration to take effect. See *Note mysql-cluster-mgm-definition::,
for more information.

To add new management servers to a running MySQL Cluster, it is also
necessary perform a rolling restart of all cluster nodes after
modifying any existing `config.ini' files. For more information about
issues arising when using multiple management nodes, see *Note
mysql-cluster-limitations-multiple-nodes::.


File: manual.info,  Node: mysql-cluster-params-api,  Next: mysql-cluster-params-other,  Prev: mysql-cluster-params-mgmd,  Up: mysql-cluster-params-overview

17.3.3.3 MySQL Cluster SQL Node and API Node Configuration Parameters
.....................................................................

The summary table in this section provides information about parameters
used in the `[mysqld]' and `[api]' sections of a `config.ini' file for
configuring MySQL Cluster SQL nodes and API nodes. For detailed
descriptions and other additional information about each of these
parameters, see *Note mysql-cluster-api-definition::.

*Note*:

For a discussion of MySQL server options for MySQL Cluster, see *Note
mysql-cluster-program-options-mysqld::; for information about MySQL
server system variables relating to MySQL Cluster, see *Note
mysql-cluster-system-variables::.

Restart types

Changes in MySQL Cluster configuration parameters do not take effect
until the cluster is restarted. The type of restart required to change
a given parameter is indicated in the summary table as follows:

   * `N'--Node restart: The parameter can be updated using a rolling
     restart (see *Note mysql-cluster-rolling-restart::).

   * `S'--System restart: The cluster must be shut down completely,
     then restarted, to effect a change in this parameter.

   * `I'--Initial restart: Data nodes must be restarted using the
     `--initial' option.

For more information about restart types, see *Note
mysql-cluster-params-overview::.

*API Node Configuration Parameters*

Name           Type/Units     Default    Min Value  Max Value  Restart
                                                               Type
ArbitrationDelaymilliseconds                         4G         N
ArbitrationRank0-2                                  2          N
BatchByteSize                                                  N
ExecuteOnComputername                                            S
HostName       name or IP                                      S
               address                                         
Id             unsigned                  1          63         N
MaxScanBatchSizebytes          256K       32K        16M        N
NodeId         unsigned                  1          63         N

*Note*:

To add new SQL or API nodes to the configuration of a running MySQL
Cluster, it is necessary to perform a rolling restart of all cluster
nodes after adding new `[mysqld]' or `[api]' sections to the
`config.ini' file (or files, if you are using more than one management
server). This must be done before the new SQL or API nodes can connect
to the cluster.

It is _not_ necessary to perform any restart of the cluster if new SQL
or API nodes can employ previously unused API slots in the cluster
configuration to connect to the cluster.


File: manual.info,  Node: mysql-cluster-params-other,  Prev: mysql-cluster-params-api,  Up: mysql-cluster-params-overview

17.3.3.4 Other MySQL Cluster Configuration Parameters
.....................................................

The summary tables in this section provide information about parameters
used in the `[computer]', `[tcp]', `[shm]', and `[sci]' sections of a
`config.ini' file for configuring MySQL Cluster management nodes. For
detailed descriptions and other additional information about individual
parameters, see *Note mysql-cluster-tcp-definition::, *Note
mysql-cluster-shm-definition::, or *Note
mysql-cluster-sci-definition::, as appropriate.

Restart types

Changes in MySQL Cluster configuration parameters do not take effect
until the cluster is restarted. The type of restart required to change
a given parameter is indicated in the summary tables as follows:

   * `N'--Node restart: The parameter can be updated using a rolling
     restart (see *Note mysql-cluster-rolling-restart::).

   * `S'--System restart: The cluster must be shut down completely,
     then restarted, to effect a change in this parameter.

   * `I'--Initial restart: Data nodes must be restarted using the
     `--initial' option.

For more information about restart types, see *Note
mysql-cluster-params-overview::.

*COMPUTER Configuration Parameters*

Name           Type/Units     Default    Min Value  Max Value  Restart
                                                               Type
HostName       name or IP                                      S
               address                                         
Id             string                                          IN

*TCP Configuration Parameters*

Name           Type/Units     Default    Min Value  Max Value  Restart
                                                               Type
Checksum                      false                            N
Group          unsigned       55                    200        N
NodeId1                                                        N
NodeId2                                                        N
NodeIdServer                                                   N
PortNumber     unsigned                             64K        N
Proxy                                                          N
ReceiveBufferMemorybytes          64K        16K        4G         N
SendBufferMemoryunsigned       256K       64K        4G         N
SendSignalId                  false                            N
                              (debug                           
                              builds:                          
                              true)                            

*SHM Configuration Parameters*

Name           Type/Units     Default    Min Value  Max Value  Restart
                                                               Type
Checksum                      true                             N
Group          unsigned       35                    200        N
NodeId1                                                        N
NodeId2                                                        N
NodeIdServer                                                   N
PortNumber     unsigned                             64K        N
SendSignalId                  false                            N
ShmKey         unsigned                             4G         N
ShmSize        bytes          1M         64K        4G         N
Signum         unsigned                             4G         N

*SCI Configuration Parameters*

Name           Type/Units     Default    Min Value  Max Value  Restart
                                                               Type
Checksum                      false                            N
Group          unsigned       15                    200        N
Host1SciId0    unsigned                             4G         N
Host1SciId1    unsigned                             4G         N
Host2SciId0    unsigned                             4G         N
Host2SciId1    unsigned                             4G         N
NodeId1                                                        N
NodeId2                                                        N
NodeIdServer                                                   N
PortNumber     unsigned                             64K        N
SendLimit      unsigned       8K         128        32K        N
SendSignalId                  true                             N
SharedBufferSizeunsigned       10M        64K        4G         N


File: manual.info,  Node: mysql-cluster-options-variables,  Next: mysql-cluster-interconnects,  Prev: mysql-cluster-params-overview,  Up: mysql-cluster-configuration

17.3.4 MySQL Server Options and Variables for MySQL Cluster
-----------------------------------------------------------

* Menu:

* mysql-cluster-option-tables::  MySQL Cluster Server Option and Variable Reference
* mysql-cluster-program-options-mysqld::  `mysqld' Command Options for MySQL Cluster
* mysql-cluster-system-variables::  MySQL Cluster System Variables
* mysql-cluster-status-variables::  MySQL Cluster Status Variables

This section provides information about MySQL server options, server
and status variables that are specific to MySQL Cluster.  For general
information on using these, and for other options and variables not
specific to MySQL Cluster, see *Note mysqld-server::.

For MySQL Cluster configuration parameters used in the cluster
confiuration file (usually named `config.ini'), see *Note
mysql-cluster-configuration::.


File: manual.info,  Node: mysql-cluster-option-tables,  Next: mysql-cluster-program-options-mysqld,  Prev: mysql-cluster-options-variables,  Up: mysql-cluster-options-variables

17.3.4.1 MySQL Cluster Server Option and Variable Reference
...........................................................

The following table provides a list of the command-line options, server
and status variables applicable within `mysqld' when it is running as
an SQL node in a MySQL Cluster. For a table showing _all_ command-line
options, server and status variables available for use with *Note
`mysqld': mysqld, see *Note mysqld-option-tables::.

*MySQL Cluster Server Options and Variables*

Name           Cmd-Line    Option file System Var  Status Var  Var Scope   Dynamic
Handler_discover                                    Yes         Both        No
have_ndbcluster                        Yes                     Global      No
ndb_autoincrement_prefetch_szYes         Yes         Yes                     Both        Yes
ndb_cache_check_timeYes         Yes         Yes                     Global      Yes
Ndb_cluster_node_id                                    Yes         Both        No
Ndb_config_from_host                                    Yes         Both        No
Ndb_config_from_port                                    Yes         Both        No
ndb_force_send Yes         Yes         Yes                     Both        Yes
ndb_index_stat_cache_entriesYes         Yes                                             
ndb_index_stat_enableYes         Yes                                             
ndb_index_stat_update_freqYes         Yes                                             
ndb-mgmd-host  Yes         Yes                                             
ndb-nodeid     Yes         Yes                     Yes         Global      No
ndb_optimized_node_selectionYes         Yes                                             
ndb_report_thresh_binlog_epoch_slipYes         Yes                                             
ndb_report_thresh_binlog_mem_usageYes         Yes                                             
ndb_use_exact_count                        Yes                     Both        Yes
ndb_use_transactionsYes         Yes         Yes                     Both        Yes
ndbcluster     Yes         Yes                                             
- _Variable_:                                                              
have_ndbcluster                                                            


File: manual.info,  Node: mysql-cluster-program-options-mysqld,  Next: mysql-cluster-system-variables,  Prev: mysql-cluster-option-tables,  Up: mysql-cluster-options-variables

17.3.4.2 `mysqld' Command Options for MySQL Cluster
...................................................

This section provides descriptions of *Note `mysqld': mysqld.  server
options relating to MySQL Cluster. For information about *Note
`mysqld': mysqld. options not specific to MySQL Cluster, and for
general information about the use of options with *Note `mysqld':
mysqld, see *Note server-options::.

For information about command-line options used with other MySQL
Cluster processes (*Note `ndbd': mysql-cluster-programs-ndbd, *Note
`ndb_mgmd': mysql-cluster-programs-ndb-mgmd, and *Note `ndb_mgm':
mysql-cluster-programs-ndb-mgm.), see *Note
mysql-cluster-program-options-common::. For information about
command-line options used with *Note `NDB': mysql-cluster. utility
programs (such as *Note `ndb_desc': mysql-cluster-programs-ndb-desc,
*Note `ndb_size.pl': mysql-cluster-programs-ndb-size-pl, and *Note
`ndb_show_tables': mysql-cluster-programs-ndb-show-tables.), see *Note
mysql-cluster-programs::.

   *  `--ndb-connectstring=CONNECT_STRING'

     Options for ndb-connectstring      *Command-Line        `--ndb-connectstring'        
     Format*                              
     *Option-File Format* `ndb-connectstring'        
                          *Permitted        
                          Values          
                          *               
     *Type*               `string'        


     When using the *Note `NDBCLUSTER': mysql-cluster.  storage engine,
     this option specifies the management server that distributes
     cluster configuration data. See *Note
     mysql-cluster-connectstring::, for syntax.

   *  `--ndb-mgmd-host=HOST[:PORT]'

     Options for ndb-mgmd-host      *Command-Line        `--ndb-mgmd-host=host[:port]'        
     Format*                              
     *Option-File Format* `ndb-mgmd-host'        
                          *Permitted        
                          Values          
                          *               
     *Type*               `string'        
     *Default*            `localhost:1186'        


     Can be used to set the host and port number of a single management
     server for the program to connect to. If the program requires node
     IDs or references to multiple management servers (or both) in its
     connection information, use the `--ndb-connectstring' option
     instead.

   *  `--ndbcluster'

     Options for ndbcluster      *Command-Line        `--ndbcluster'        
     Format*                              
     *Option-File Format* `ndbcluster'        
     *Option Sets         Yes,            
     Variable*            `have_ndbcluster'        
     *Disabled by*        `skip-ndbcluster'        
                          *Permitted        
                          Values          
                          *               
     *Type*               `boolean'        
     *Default*            `FALSE'         


     The *Note `NDBCLUSTER': mysql-cluster. storage engine is necessary
     for using MySQL Cluster. If a *Note `mysqld': mysqld. binary
     includes support for the *Note `NDBCLUSTER': mysql-cluster.
     storage engine, the engine is disabled by default. Use the
     `--ndbcluster' option to enable it. Use `--skip-ndbcluster' to
     explicitly disable the engine.

   *  `--ndb-nodeid=#'

     Options for ndb-nodeid      *Version Introduced* 5.0.45          
     *Command-Line        `--ndb-nodeid=#'        
     Format*                              
     *Option-File Format* `ndb-nodeid'        
     *Variable Name*      `Ndb_cluster_node_id'        
     *Variable Scope*     Global          
     *Dynamic Variable*   No              
                          *Permitted        
                          Values          
                          (>=             
                          5.0.45)*        
     *Type*               `numeric'        
     *Range*              `1 ..           
                          63'             


     Set this MySQL server's node ID in a MySQL Cluster.  This can be
     used instead of specifying the node ID as part of the
     connectstring or in the `config.ini' file, or permitting the
     cluster to determine an arbitrary node ID. If you use this option,
     then `--ndb-nodeid' must be specified _before_
     `--ndb-connectstring'. If `--ndb-nodeid' is used _and_ a node ID
     is specified in the connectstring, then the MySQL server will not
     be able to connect to the cluster. In addition, if `--nodeid' is
     used, then either a matching node ID must be found in a `[mysqld]'
     or `[api]' section of `config.ini', or there must be an `open'
     `[mysqld]' or `[api]' section in the file (that is, a section
     without an `Id' parameter specified).

     Regardless of how the node ID is determined, its is shown as the
     value of the global status variable `Ndb_cluster_node_id' in the
     output of *Note `SHOW STATUS': show-status, and as
     `cluster_node_id' in the `connection' row of the output of *Note
     `SHOW ENGINE NDBCLUSTER STATUS': show-engine.

     For more information about node IDs for MySQL Cluster SQL nodes,
     see *Note mysql-cluster-api-definition::.

   *  `--skip-ndbcluster'

     Options for skip-ndbcluster      *Command-Line        `--skip-ndbcluster'        
     Format*                              
     *Option-File Format* `skip-ndbcluster'        


     Disable the *Note `NDBCLUSTER': mysql-cluster. storage engine.
     This is the default for binaries that were built with *Note
     `NDBCLUSTER': mysql-cluster. storage engine support; the server
     allocates memory and other resources for this storage engine only
     if the `--ndbcluster' option is given explicitly. See *Note
     mysql-cluster-quick::, for an example.


File: manual.info,  Node: mysql-cluster-system-variables,  Next: mysql-cluster-status-variables,  Prev: mysql-cluster-program-options-mysqld,  Up: mysql-cluster-options-variables

17.3.4.3 MySQL Cluster System Variables
.......................................

This section provides detailed information about MySQL server system
variables that are specific to MySQL Cluster and the *Note `NDB':
mysql-cluster. storage engine. For system variables not specific to
MySQL Cluster, see *Note server-system-variables::. For general
information on using system variables, see *Note
using-system-variables::.

   *  `have_ndbcluster'

     Options for have_ndbcluster      *Variable Name*      `have_ndbcluster'        
     *Variable Scope*     Global          
     *Dynamic Variable*   No              
                          *Permitted        
                          Values          
                          *               
     *Type*               `boolean'        


     `YES' if *Note `mysqld': mysqld. supports *Note `NDBCLUSTER':
     mysql-cluster. tables.  `DISABLED' if `--skip-ndbcluster' is used.

     This variable is deprecated in MySQL 5.1, and is removed in MySQL
     5.6. Use *Note `SHOW ENGINES': show-engines.  instead.

   *  `multi_range_count'

     Options for multi_range_count      *Version Introduced* 5.0.3           
     *Command-Line        `--multi_range_count=#'        
     Format*                              
     *Option-File Format* `multi_range_count'        
     *Option Sets         Yes,            
     Variable*            `multi_range_count'        
     *Variable Name*      `multi_range_count'        
     *Variable Scope*     Global,         
                          Session         
     *Dynamic Variable*   Yes             
                          *Permitted        
                          Values          
                          *               
     *Type*               `numeric'        
     *Default*            `256'           
     *Range*              `1 ..           
                          4294967295'        


     The maximum number of ranges to send to a table handler at once
     during range selects. The default value is 256. Sending multiple
     ranges to a handler at once can improve the performance of certain
     selects dramatically. This is especially true for the *Note
     `NDBCLUSTER': mysql-cluster. table handler, which needs to send
     the range requests to all nodes. Sending a batch of those requests
     at once reduces communication costs significantly.

     This variable was added in MySQL 5.0.3.

   *  `ndb_autoincrement_prefetch_sz'

     Options for ndb_autoincrement_prefetch_sz      *Command-Line        `--ndb_autoincrement_prefetch_sz'        
     Format*                              
     *Option-File Format* `ndb_autoincrement_prefetch_sz'        
     *Option Sets         Yes,            
     Variable*            `ndb_autoincrement_prefetch_sz'        
     *Variable Name*      `ndb_autoincrement_prefetch_sz'        
     *Variable Scope*     Global,         
                          Session         
     *Dynamic Variable*   Yes             
                          *Permitted        
                          Values          
                          (<=             
                          5.0.54)*        
     *Type*               `numeric'        
     *Default*            `32'            
     *Range*              `1 ..           
                          256'            
                          *Permitted        
                          Values          
                          (>=             
                          5.0.56)*        
     *Type*               `numeric'        
     *Default*            `1'             
     *Range*              `1 ..           
                          256'            


     Determines the probability of gaps in an autoincremented column.
     Set it to `1' to minimize this.  Setting it to a high value for
     optimization--makes inserts faster, but decreases the likelihood
     that consecutive autoincrement numbers will be used in a batch of
     inserts. Default value: `32'. Minimum value: `1'.

     Beginning with MySQL 5.0.56, this variable affects the number of
     `AUTO_INCREMENT' IDs that are fetched between statements only.
     Within a statement, at least 32 IDs are now obtained at a time.
     The default value for `ndb_autoincrement_prefetch_sz' is now `1',
     to increase the speed of statements inserting single rows. (Bug
     #31956)

   *  `ndb_cache_check_time'

     Options for ndb_cache_check_time      *Command-Line        `--ndb_cache_check_time'        
     Format*                              
     *Option-File Format* `ndb_cache_check_time'        
     *Option Sets         Yes,            
     Variable*            `ndb_cache_check_time'        
     *Variable Name*      `ndb_cache_check_time'        
     *Variable Scope*     Global          
     *Dynamic Variable*   Yes             
                          *Permitted        
                          Values          
                          *               
     *Type*               `numeric'        
     *Default*            `0'             


     The number of milliseconds that elapse between checks of MySQL
     Cluster SQL nodes by the MySQL query cache. Setting this to 0 (the
     default and minimum value) means that the query cache checks for
     validation on every query.

     The recommended maximum value for this variable is 1000, which
     means that the check is performed once per second. A larger value
     means that the check is performed and possibly invalidated due to
     updates on different SQL nodes less often. It is generally not
     desirable to set this to a value greater than 2000.

   *  `ndb_force_send'

     Options for ndb_force_send      *Command-Line        `--ndb-force-send'        
     Format*                              
     *Option-File Format* `ndb_force_send'        
     *Option Sets         Yes,            
     Variable*            `ndb_force_send'        
     *Variable Name*      `ndb_force_send'        
     *Variable Scope*     Global,         
                          Session         
     *Dynamic Variable*   Yes             
                          *Permitted        
                          Values          
                          *               
     *Type*               `boolean'        
     *Default*            `TRUE'          


     Forces sending of buffers to *Note `NDB': mysql-cluster.
     immediately, without waiting for other threads. Defaults to `ON'.

   *  `ndb_index_stat_cache_entries'

     Options for ndb_index_stat_cache_entries      *Command-Line        `--ndb_index_stat_cache_entries'        
     Format*                              
     *Option-File Format* `ndb_index_stat_cache_entries'        
                          *Permitted        
                          Values          
                          *               
     *Type*               `numeric'        
     *Default*            `32'            
     *Range*              `0 ..           
                          4294967295'        


     Sets the granularity of the statistics by determining the number
     of starting and ending keys to store in the statistics memory
     cache. Zero means no caching takes place; in this case, the data
     nodes are always queried directly.  Default value: `32'.

   *  `ndb_index_stat_enable'

     Options for ndb_index_stat_enable      *Command-Line        `--ndb_index_stat_enable'        
     Format*                              
     *Option-File Format* `ndb_index_stat_enable'        
                          *Permitted        
                          Values          
                          *               
     *Type*               `boolean'        
     *Default*            `ON'            


     Use *Note `NDB': mysql-cluster. index statistics in query
     optimization. Defaults to `ON'.

   *  `ndb_index_stat_update_freq'

     Options for ndb_index_stat_update_freq      *Command-Line        `--ndb_index_stat_update_freq'        
     Format*                              
     *Option-File Format* `ndb_index_stat_update_freq'        
                          *Permitted        
                          Values          
                          *               
     *Type*               `numeric'        
     *Default*            `20'            
     *Range*              `0 ..           
                          4294967295'        


     How often to query data nodes instead of the statistics cache. For
     example, a value of `20' (the default) means to direct every 20^th
     query to the data nodes.

   *  `ndb_optimized_node_selection'

     Options for ndb_optimized_node_selection      *Command-Line        `--ndb-optimized-node-selection'4.1.9-5.1.22-ndb-6.33
     Format*                              
     **                   `--ndb-optimized-node-selection=#'        
     *Option-File Format* `ndb_optimized_node_selection'        


     Causes an SQL node to use the `closest' data node as transaction
     coordinator. For this purpose, a data node having a shared memory
     connection with the SQL node is considered to be `closest' to the
     SQL node; the next closest (in order of decreasing proximity) are:
     TCP connection to `localhost'; SCI connection; TCP connection from
     a host other than `localhost'.

     This option is enabled by default. Set to `0' or `OFF' to disable
     it, in which case the SQL node uses each data node in the cluster
     in succession. When this option is disabled each SQL thread
     attempts to use a given data node 8 times before proceeding to the
     next one.

   *  `ndb_report_thresh_binlog_epoch_slip'

     Options for ndb_report_thresh_binlog_epoch_slip      *Command-Line        `--ndb_report_thresh_binlog_epoch_slip'        
     Format*                              
     *Option-File Format* `ndb_report_thresh_binlog_epoch_slip'        
                          *Permitted        
                          Values          
                          *               
     *Type*               `numeric'        
     *Default*            `3'             
     *Range*              `0 ..           
                          256'            


     This is a threshold on the number of epochs to be behind before
     reporting binlog status. For example, a value of `3' (the default)
     means that if the difference between which epoch has been received
     from the storage nodes and which epoch has been applied to the
     binlog is 3 or more, a status message will be sent to the cluster
     log.

   *  `ndb_report_thresh_binlog_mem_usage'

     Options for ndb_report_thresh_binlog_mem_usage      *Command-Line        `--ndb_report_thresh_binlog_mem_usage'        
     Format*                              
     *Option-File Format* `ndb_report_thresh_binlog_mem_usage'        
                          *Permitted        
                          Values          
                          *               
     *Type*               `numeric'        
     *Default*            `10'            
     *Range*              `0 ..           
                          10'             


     This is a threshold on the percentage of free memory remaining
     before reporting binlog status. For example, a value of `10' (the
     default) means that if the amount of available memory for
     receiving binlog data from the data nodes falls below 10%, a
     status message will be sent to the cluster log.

   *  `ndb_use_exact_count'

     Options for ndb_use_exact_count      *Variable Name*      `ndb_use_exact_count'        
     *Variable Scope*     Global,         
                          Session         
     *Dynamic Variable*   Yes             
                          *Permitted        
                          Values          
                          *               
     *Type*               `boolean'        
     *Default*            `ON'            


     Forces *Note `NDB': mysql-cluster. to use a count of records
     during `SELECT COUNT(*)' query planning to speed up this type of
     query. The default value is `ON'. For faster queries overall,
     disable this feature by setting the value of `ndb_use_exact_count'
     to `OFF'.

   *  `ndb_use_transactions'

     Options for ndb_use_transactions      *Command-Line        `--ndb_use_transactions'        
     Format*                              
     *Option-File Format* `ndb_use_transactions'        
     *Variable Name*      `ndb_use_transactions'        
     *Variable Scope*     Global,         
                          Session         
     *Dynamic Variable*   Yes             
                          *Permitted        
                          Values          
                          *               
     *Type*               `boolean'        
     *Default*            `ON'            


     You can disable *Note `NDB': mysql-cluster. transaction support by
     setting this variable's values to `OFF' (not recommended). The
     default is `ON'.


File: manual.info,  Node: mysql-cluster-status-variables,  Prev: mysql-cluster-system-variables,  Up: mysql-cluster-options-variables

17.3.4.4 MySQL Cluster Status Variables
.......................................

This section provides detailed information about MySQL server status
variables that relate to MySQL Cluster and the *Note `NDB':
mysql-cluster. storage engine. For status variables not specific to
MySQL Cluster, and for general information on using status variables,
see *Note server-status-variables::.

   *  `Handler_discover'

     The MySQL server can ask the *Note `NDBCLUSTER': mysql-cluster.
     storage engine if it knows about a table with a given name. This
     is called discovery.  `Handler_discover' indicates the number of
     times that tables have been discovered using this mechanism.

   *  `Ndb_cluster_node_id'

     If the server is acting as a MySQL Cluster node, then the value of
     this variable its node ID in the cluster.

     If the server is not part of a MySQL Cluster, then the value of
     this variable is 0.

   *  `Ndb_config_from_host'

     If the server is part of a MySQL Cluster, the value of this
     variable is the host name or IP address of the Cluster management
     server from which it gets its configuration data.

     If the server is not part of a MySQL Cluster, then the value of
     this variable is an empty string.

     Prior to MySQL 5.0.23, this variable was named
     `Ndb_connected_host'.

   *  `Ndb_config_from_port'

     If the server is part of a MySQL Cluster, the value of this
     variable is the number of the port through which it is connected
     to the Cluster management server from which it gets its
     configuration data.

     If the server is not part of a MySQL Cluster, then the value of
     this variable is 0.

     Prior to MySQL 5.0.23, this variable was named
     `Ndb_connected_port'.

   *  `Ndb_number_of_data_nodes'

     If the server is part of a MySQL Cluster, the value of this
     variable is the number of data nodes in the cluster.

     If the server is not part of a MySQL Cluster, then the value of
     this variable is 0.

     Prior to MySQL 5.0.29, this variable was named
     `Ndb_number_of_storage_nodes'.


File: manual.info,  Node: mysql-cluster-interconnects,  Prev: mysql-cluster-options-variables,  Up: mysql-cluster-configuration

17.3.5 Using High-Speed Interconnects with MySQL Cluster
--------------------------------------------------------

* Menu:

* mysql-cluster-sci-sockets::    Configuring MySQL Cluster to use SCI Sockets
* mysql-cluster-interconnects-performance::  MySQL Cluster Interconnects and Performance

Even before design of *Note `NDBCLUSTER': mysql-cluster.  began in
1996, it was evident that one of the major problems to be encountered
in building parallel databases would be communication between the nodes
in the network. For this reason, *Note `NDBCLUSTER': mysql-cluster. was
designed from the very beginning to permit the use of a number of
different data transport mechanisms. In this Manual, we use the term
_transporter_ for these.

The MySQL Cluster codebase includes support for four different
transporters:

   * _TCP/IP using 100 Mbps or gigabit Ethernet_, as discussed in *Note
     mysql-cluster-tcp-definition::.

   * _Direct (machine-to-machine) TCP/IP_; although this transporter
     uses the same TCP/IP protocol as mentioned in the previous item,
     it requires setting up the hardware differently and is configured
     differently as well.  For this reason, it is considered a separate
     transport mechanism for MySQL Cluster. See *Note
     mysql-cluster-tcp-definition-direct::, for details.

   * _Shared memory (SHM)_. For more information about SHM, see *Note
     mysql-cluster-shm-definition::.

     *Note*:

     SHM is considered experimental only, and is not officially
     supported.

   * _Scalable Coherent Interface (SCI)_, as described in the next
     section of this chapter, *Note mysql-cluster-sci-definition::.

Most users today employ TCP/IP over Ethernet because it is ubiquitous.
TCP/IP is also by far the best-tested transporter for use with MySQL
Cluster.

We are working to make sure that communication with the *Note `ndbd':
mysql-cluster-programs-ndbd. process is made in `chunks' that are as
large as possible because this benefits all types of data transmission.

For users who desire it, it is also possible to use cluster
interconnects to enhance performance even further. There are two ways
to achieve this: Either a custom transporter can be designed to handle
this case, or you can use socket implementations that bypass the TCP/IP
stack to one extent or another. We have experimented with both of these
techniques using the SCI (Scalable Coherent Interface) technology
developed by Dolphin Interconnect Solutions
(http://www.dolphinics.com/).


File: manual.info,  Node: mysql-cluster-sci-sockets,  Next: mysql-cluster-interconnects-performance,  Prev: mysql-cluster-interconnects,  Up: mysql-cluster-interconnects

17.3.5.1 Configuring MySQL Cluster to use SCI Sockets
.....................................................

It is possible employing Scalable Coherent Interface (SCI) technology
to achieve a significant increase in connection speeds and throughput
between MySQL Cluster data and SQL nodes.  To use SCI, it is necessary
to obtain and install Dolphin SCI network cards and to use the drivers
and other software supplied by Dolphin. You can get information on
obtaining these, from Dolphin Interconnect Solutions
(http://www.dolphinics.com/). SCI SuperSocket or SCI Transporter
support is available for 32-bit and 64-bit Linux, Solaris, and other
platforms. See the Dolphin documentation referenced later in this
section for more detailed information regarding platforms supported for
SCI.

*Note*:

Prior to MySQL 5.0.66, there were issues with building MySQL Cluster
with SCI support (see Bug #25470), but these have been resolved due to
work contributed by Dolphin. SCI Sockets are now correctly supported
for MySQL Cluster hosts running recent versions of Linux using the
`-max' builds, and versions of MySQL Cluster with SCI Transporter
support can be built using either of `compile-amd64-max-sci' or
`compile-pentium64-max-sci'. Both of these build scripts can be found
in the `BUILD' directory of the MySQL Cluster source trees; it should
not be difficult to adapt them for other platforms. Generally, all that
is necessary is to compile MySQL Cluster with SCI Transporter support
is to configure the MySQL Cluster build using `--with-ndb-sci=/opt/DIS'.

Once you have acquired the required Dolphin hardware and software, you
can obtain detailed information on how to adapt a MySQL Cluster
configured for normal TCP/IP communication to use SCI from the from the
Dolphin SCI online documentation
(http://www.dolphinics.com/support/sci-product-documentation-software.html).


File: manual.info,  Node: mysql-cluster-interconnects-performance,  Prev: mysql-cluster-sci-sockets,  Up: mysql-cluster-interconnects

17.3.5.2 MySQL Cluster Interconnects and Performance
....................................................

The *Note `ndbd': mysql-cluster-programs-ndbd. process has a number of
simple constructs which are used to access the data in a MySQL Cluster.
We have created a very simple benchmark to check the performance of
each of these and the effects which various interconnects have on their
performance.

There are four access methods:

   * Primary key access

     This is access of a record through its primary key. In the
     simplest case, only one record is accessed at a time, which means
     that the full cost of setting up a number of TCP/IP messages and a
     number of costs for context switching are borne by this single
     request. In the case where multiple primary key accesses are sent
     in one batch, those accesses share the cost of setting up the
     necessary TCP/IP messages and context switches. If the TCP/IP
     messages are for different destinations, additional TCP/IP
     messages need to be set up.

   * Unique key access

     Unique key accesses are similar to primary key accesses, except
     that a unique key access is executed as a read on an index table
     followed by a primary key access on the table. However, only one
     request is sent from the MySQL Server, and the read of the index
     table is handled by *Note `ndbd': mysql-cluster-programs-ndbd.
     Such requests also benefit from batching.

   * Full table scan

     When no indexes exist for a lookup on a table, a full table scan
     is performed. This is sent as a single request to the *Note
     `ndbd': mysql-cluster-programs-ndbd. process, which then divides
     the table scan into a set of parallel scans on all cluster *Note
     `ndbd': mysql-cluster-programs-ndbd. processes. In future versions
     of MySQL Cluster, an SQL node will be able to filter some of these
     scans.

   * *Range scan using ordered index*

     When an ordered index is used, it performs a scan in the same
     manner as the full table scan, except that it scans only those
     records which are in the range used by the query transmitted by
     the MySQL server (SQL node). All partitions are scanned in
     parallel when all bound index attributes include all attributes in
     the partitioning key.

With benchmarks developed internally by MySQL for testing simple and
batched primary and unique key accesses, we have found that using SCI
sockets improves performance by approximately 100% over TCP/IP, except
in rare instances when communication performance is not an issue. This
can occur when scan filters make up most of processing time or when
very large batches of primary key accesses are achieved. In that case,
the CPU processing in the *Note `ndbd': mysql-cluster-programs-ndbd.
processes becomes a fairly large part of the overhead.

Using the SCI transporter instead of SCI Sockets is only of interest in
communicating between *Note `ndbd': mysql-cluster-programs-ndbd.
processes. Using the SCI transporter is also only of interest if a CPU
can be dedicated to the *Note `ndbd': mysql-cluster-programs-ndbd.
process because the SCI transporter ensures that this process will never
go to sleep. It is also important to ensure that the *Note `ndbd':
mysql-cluster-programs-ndbd. process priority is set in such a way that
the process does not lose priority due to running for an extended
period of time, as can be done by locking processes to CPUs in Linux
2.6. If such a configuration is possible, the *Note `ndbd':
mysql-cluster-programs-ndbd. process will benefit by 10-70% as compared
with using SCI sockets. (The larger figures will be seen when
performing updates and probably on parallel scan operations as well.)

There are several other optimized socket implementations for computer
clusters, including Myrinet, Gigabit Ethernet, Infiniband and the VIA
interface. However, we have tested MySQL Cluster so far only with SCI
sockets. See *Note mysql-cluster-sci-sockets::, for information on how
to set up SCI sockets using ordinary TCP/IP for MySQL Cluster.


File: manual.info,  Node: mysql-cluster-programs,  Next: mysql-cluster-management,  Prev: mysql-cluster-configuration,  Up: mysql-cluster

17.4 MySQL Cluster Programs
===========================

* Menu:

* mysql-cluster-programs-mysqld::  MySQL Server Usage for MySQL Cluster
* mysql-cluster-programs-ndbd::  `ndbd' --- The MySQL Cluster Data Node Daemon
* mysql-cluster-programs-ndb-mgmd::  `ndb_mgmd' --- The MySQL Cluster Management Server Daemon
* mysql-cluster-programs-ndb-mgm::  `ndb_mgm' --- The MySQL Cluster Management Client
* mysql-cluster-programs-ndb-config::  `ndb_config' --- Extract MySQL Cluster Configuration Information
* mysql-cluster-programs-ndb-cpcd::  `ndb_cpcd' --- Automate Testing for NDB Development
* mysql-cluster-programs-ndb-delete-all::  `ndb_delete_all' --- Delete All Rows from an NDB Table
* mysql-cluster-programs-ndb-desc::  `ndb_desc' --- Describe NDB Tables
* mysql-cluster-programs-ndb-drop-index::  `ndb_drop_index' --- Drop Index from an NDB Table
* mysql-cluster-programs-ndb-drop-table::  `ndb_drop_table' --- Drop an NDB Table
* mysql-cluster-programs-ndb-error-reporter::  `ndb_error_reporter' --- NDB Error-Reporting Utility
* mysql-cluster-programs-ndb-print-backup-file::  `ndb_print_backup_file' --- Print NDB Backup File Contents
* mysql-cluster-programs-ndb-print-schema-file::  `ndb_print_schema_file' --- Print NDB Schema File Contents
* mysql-cluster-programs-ndb-print-sys-file::  `ndb_print_sys_file' --- Print NDB System File Contents
* mysql-cluster-programs-ndb-restore::  `ndb_restore' --- Restore a MySQL Cluster Backup
* mysql-cluster-programs-ndb-select-all::  `ndb_select_all' --- Print Rows from an NDB Table
* mysql-cluster-programs-ndb-select-count::  `ndb_select_count' --- Print Row Counts for NDB Tables
* mysql-cluster-programs-ndb-show-tables::  `ndb_show_tables' --- Display List of NDB Tables
* mysql-cluster-programs-ndb-size-pl::  `ndb_size.pl' --- NDBCLUSTER Size Requirement Estimator
* mysql-cluster-programs-ndb-waiter::  `ndb_waiter' --- Wait for MySQL Cluster to Reach a Given Status
* mysql-cluster-program-options-common::  Options Common to MySQL Cluster Programs

Using and managing a MySQL Cluster requires several specialized
programs, which we describe in this chapter. We discuss the purposes of
these programs in a MySQL Cluster, how to use the programs, and what
startup options are available for each of them.

These programs include the MySQL Cluster data, management, and SQL node
processes (*Note `ndbd': mysql-cluster-programs-ndbd, *Note `ndb_mgmd':
mysql-cluster-programs-ndb-mgmd, and *Note `mysqld': mysqld.) and the
management client (*Note `ndb_mgm': mysql-cluster-programs-ndb-mgm.).

Other NDB utility, diagnostic, and example programs are included with
the MySQL Cluster distribution. These include *Note `ndb_restore':
mysql-cluster-programs-ndb-restore, *Note `ndb_show_tables':
mysql-cluster-programs-ndb-show-tables, and *Note `ndb_config':
mysql-cluster-programs-ndb-config. These programs are covered later in
this chapter.

The last two sections of this chapter contain tables of options used,
respectively, with *Note `mysqld': mysqld. and with the various NDB
programs.


File: manual.info,  Node: mysql-cluster-programs-mysqld,  Next: mysql-cluster-programs-ndbd,  Prev: mysql-cluster-programs,  Up: mysql-cluster-programs

17.4.1 MySQL Server Usage for MySQL Cluster
-------------------------------------------

*Note `mysqld': mysqld. is the traditional MySQL server process.  To be
used with MySQL Cluster, *Note `mysqld': mysqld. needs to be built with
support for the *Note `NDBCLUSTER': mysql-cluster. storage engine, as
it is in the precompiled binaries available from
`http://dev.mysql.com/downloads/'. If you build MySQL from source, you
must invoke `configure' with the `--with-ndbcluster' option to enable
`NDB Cluster' storage engine support.

For information about other MySQL server options and variables relevant
to MySQL Cluster in addition to those discussed in this section, see
*Note mysql-cluster-options-variables::.

If the *Note `mysqld': mysqld. binary has been built with Cluster
support, the *Note `NDBCLUSTER': mysql-cluster.  storage engine is
still disabled by default. You can use either of two possible options
to enable this engine:

   * Use `--ndbcluster' as a startup option on the command line when
     starting *Note `mysqld': mysqld.

   * Insert a line containing *Note `NDBCLUSTER': mysql-cluster. in the
     `[mysqld]' section of your `my.cnf' file.

An easy way to verify that your server is running with the *Note
`NDBCLUSTER': mysql-cluster. storage engine enabled is to issue the
*Note `SHOW ENGINES': show-engines. statement in the MySQL Monitor
(*Note `mysql': mysql.). You should see the value `YES' as the `Support'
value in the row for *Note `NDBCLUSTER': mysql-cluster. If you see `NO'
in this row or if there is no such row displayed in the output, you are
not running an *Note `NDB': mysql-cluster.-enabled version of MySQL. If
you see `DISABLED' in this row, you need to enable it in either one of
the two ways just described.

To read cluster configuration data, the MySQL server requires at a
minimum three pieces of information:

   * The MySQL server's own cluster node ID

   * The host name or IP address for the management server (MGM node)

   * The number of the TCP/IP port on which it can connect to the
     management server

Node IDs can be allocated dynamically, so it is not strictly necessary
to specify them explicitly.

The *Note `mysqld': mysqld. parameter `ndb-connectstring' is used to
specify the connectstring either on the command line when starting
*Note `mysqld': mysqld. or in `my.cnf'. The connectstring contains the
host name or IP address where the management server can be found, as
well as the TCP/IP port it uses.

In the following example, `ndb_mgmd.mysql.com' is the host where the
management server resides, and the management server listens for
cluster messages on port 1186:

     shell> mysqld --ndbcluster --ndb-connectstring=ndb_mgmd.mysql.com:1186

See *Note mysql-cluster-connectstring::, for more information on
connectstrings.

Given this information, the MySQL server will be a full participant in
the cluster. (We often refer to a *Note `mysqld': mysqld. process
running in this manner as an SQL node.) It will be fully aware of all
cluster data nodes as well as their status, and will establish
connections to all data nodes. In this case, it is able to use any data
node as a transaction coordinator and to read and update node data.

You can see in the *Note `mysql': mysql. client whether a MySQL server
is connected to the cluster using *Note `SHOW PROCESSLIST':
show-processlist. If the MySQL server is connected to the cluster, and
you have the `PROCESS' privilege, then the first row of the output is
as shown here:

     mysql> SHOW PROCESSLIST \G
     *************************** 1. row ***************************
          Id: 1
        User: system user
        Host:
          db:
     Command: Daemon
        Time: 1
       State: Waiting for event from ndbcluster
        Info: NULL

*Important*:

To participate in a MySQL Cluster, the *Note `mysqld': mysqld.  process
must be started with _both_ the options `--ndbcluster' and
`--ndb-connectstring' (or their equivalents in `my.cnf'). If *Note
`mysqld': mysqld. is started with only the `--ndbcluster' option, or if
it is unable to contact the cluster, it is not possible to work with
*Note `NDB': mysql-cluster. tables, _nor is it possible to create any
new tables regardless of storage engine_. The latter restriction is a
safety measure intended to prevent the creation of tables having the
same names as *Note `NDB': mysql-cluster. tables while the SQL node is
not connected to the cluster. If you wish to create tables using a
different storage engine while the *Note `mysqld': mysqld.  process is
not participating in a MySQL Cluster, you must restart the server
_without_ the `--ndbcluster' option.


File: manual.info,  Node: mysql-cluster-programs-ndbd,  Next: mysql-cluster-programs-ndb-mgmd,  Prev: mysql-cluster-programs-mysqld,  Up: mysql-cluster-programs

17.4.2 `ndbd' -- The MySQL Cluster Data Node Daemon
---------------------------------------------------

*Note `ndbd': mysql-cluster-programs-ndbd. is the process that is used
to handle all the data in tables using the NDB Cluster storage engine.
This is the process that empowers a data node to accomplish distributed
transaction handling, node recovery, checkpointing to disk, online
backup, and related tasks.

In a MySQL Cluster, a set of *Note `ndbd': mysql-cluster-programs-ndbd.
processes cooperate in handling data. These processes can execute on the
same computer (host) or on different computers. The correspondences
between data nodes and Cluster hosts is completely configurable.

The following table includes command options specific to the MySQL
Cluster data node program *Note `ndbd': mysql-cluster-programs-ndbd.
Additional descriptions follow the table. For options common to all
MySQL Cluster programs, see *Note
mysql-cluster-program-options-common::.

*`ndbd' Command Line Options*

Format         Description                          IntroductionDeprecatedRemoved
-bind-address=nameLocal bind address                   5.0.29          
-daemon        Start ndbd as daemon (default);                      
               override with -nodaemon                              
-foreground    Run ndbd in foreground, provided                     
               for debugging purposes (implies                      
               -nodaemon)                                           
-initial       Perform initial start of ndbd,                       
               including cleaning the file system.                  
               Consult the documentation before                     
               using this option                                    
-initial-start Perform partial initial start        5.0.21          
               (requires -nowait-nodes)                             
-nodaemon      Do not start ndbd as daemon;                         
               provided for testing purposes                        
-nostart       Don't start ndbd immediately; ndbd                   
               waits for command to start  from                     
               ndb_mgmd                                             
-nowait-nodes=listDo not wait for these data nodes to  5.0.21          
               start (takes comma-separated  list                   
               of node IDs). Also requires                          
               -ndb-nodeid to be used.                              

   *  `--bind-address'

     Options for bind-address      *Version Introduced* 5.0.29          
     *Command-Line        `--bind-address=name'        
     Format*                              
                          *Permitted        
                          Values          
                          *               
     *Type*               `string'        
     *Default*            `'              


     Causes *Note `ndbd': mysql-cluster-programs-ndbd. to bind to a
     specific network interface (host name or IP address). This option
     has no default value.

     This option was added in MySQL 5.0.29.

   *  `--daemon', `-d'

     Options for daemon      *Command-Line        `--daemon'        
     Format*                              
     **                   `-d'            
                          *Permitted        
                          Values          
                          *               
     *Type*               `boolean'        
     *Default*            `TRUE'          


     Instructs *Note `ndbd': mysql-cluster-programs-ndbd. to execute as
     a daemon process. This is the default behavior.  `--nodaemon' can
     be used to prevent the process from running as a daemon.

   * `--initial'

     Options for initial      *Command-Line        `--initial'        
     Format*                              
                          *Permitted        
                          Values          
                          *               
     *Type*               `boolean'        
     *Default*            `FALSE'         


     Instructs *Note `ndbd': mysql-cluster-programs-ndbd. to perform an
     initial start. An initial start erases any files created for
     recovery purposes by earlier instances of *Note `ndbd':
     mysql-cluster-programs-ndbd. It also re-creates recovery log
     files. Note that on some operating systems this process can take a
     substantial amount of time.

     An `--initial' start is to be used _only_ when starting the *Note
     `ndbd': mysql-cluster-programs-ndbd. process under very special
     circumstances; this is because this option causes all files to be
     removed from the Cluster file system and all redo log files to be
     re-created. These circumstances are listed here:

        * When performing a software upgrade which has changed the
          contents of any files.

        * When restarting the node with a new version of *Note `ndbd':
          mysql-cluster-programs-ndbd.

        * As a measure of last resort when for some reason the node
          restart or system restart repeatedly fails. In this case, be
          aware that this node can no longer be used to restore data
          due to the destruction of the data files.

     Use of this option prevents the `StartPartialTimeout' and
     `StartPartitionedTimeout' configuration parameters from having any
     effect.

     *Important*:

     This option does _not_ affect any backup files that have already
     been created by the affected node.

     This option also has no effect on recovery of data by a data node
     that is just starting (or restarting) from data nodes that are
     already running. This recovery of data occurs automatically, and
     requires no user intervention in a MySQL Cluster that is running
     normally.

     It is permissible to use this option when starting the cluster for
     the very first time (that is, before any data node files have been
     created); however, it is _not_ necessary to do so.

   * `--initial-start'

     Options for initial-start      *Version Introduced* 5.0.21          
     *Command-Line        `--initial-start'        
     Format*                              
                          *Permitted        
                          Values          
                          *               
     *Type*               `boolean'        
     *Default*            `FALSE'         


     This option is used when performing a partial initial start of the
     cluster. Each node should be started with this option, as well as
     `--nowait-nodes'.

     Suppose that you have a 4-node cluster whose data nodes have the
     IDs 2, 3, 4, and 5, and you wish to perform a partial initial
     start using only nodes 2, 4, and 5--that is, omitting node 3:

          shell> ndbd --ndb-nodeid=2 --nowait-nodes=3 --initial-start
          shell> ndbd --ndb-nodeid=4 --nowait-nodes=3 --initial-start
          shell> ndbd --ndb-nodeid=5 --nowait-nodes=3 --initial-start

     This option was added in MySQL 5.0.21.

   * `--nowait-nodes=NODE_ID_1[, NODE_ID_2[, ...]]'

     Options for nowait-nodes      *Version Introduced* 5.0.21          
     *Command-Line        `--nowait-nodes=list'        
     Format*                              
                          *Permitted        
                          Values          
                          *               
     *Type*               `string'        
     *Default*            `'              


     This option takes a list of data nodes which for which the cluster
     will not wait for before starting.

     This can be used to start the cluster in a partitioned state. For
     example, to start the cluster with only half of the data nodes
     (nodes 2, 3, 4, and 5) running in a 4-node cluster, you can start
     each *Note `ndbd': mysql-cluster-programs-ndbd.  process with
     `--nowait-nodes=3,5'. In this case, the cluster starts as soon as
     nodes 2 and 4 connect, and does _not_ wait
     `StartPartitionedTimeout' milliseconds for nodes 3 and 5 to
     connect as it would otherwise.

     If you wanted to start up the same cluster as in the previous
     example without one *Note `ndbd':
     mysql-cluster-programs-ndbd.--say, for example, that the host
     machine for node 3 has suffered a hardware failure--then start
     nodes 2, 4, and 5 with `--nowait-nodes=3'. Then the cluster will
     start as soon as nodes 2, 4, and 5 connect and will not wait for
     node 3 to start.

     When using this option, you must also specify the node ID for the
     data node being started with the `--ndb-nodeid' option.

     This option was added in MySQL 5.0.21.

   * `--nodaemon'

     Options for nodaemon      *Command-Line        `--nodaemon'        
     Format*                              
                          *Permitted        
                          Values          
                          *               
     *Type*               `boolean'        
     *Default*            `FALSE'         
                          *Permitted        
                          Values          
                          *               
     *Type* (windows)     `boolean'        
     *Default*            `TRUE'          


     Instructs *Note `ndbd': mysql-cluster-programs-ndbd. not to start
     as a daemon process. This is useful when *Note `ndbd':
     mysql-cluster-programs-ndbd. is being debugged and you want output
     to be redirected to the screen.

   *  `--foreground'

     Options for foreground      *Command-Line        `--foreground'        
     Format*                              
                          *Permitted        
                          Values          
                          *               
     *Type*               `boolean'        
     *Default*            `FALSE'         


     Causes *Note `ndbd': mysql-cluster-programs-ndbd. to execute as a
     foreground process, primarily for debugging purposes. This option
     implies the `--nodaemon' option.

   * `--nostart', `-n'

     Options for nostart      *Command-Line        `--nostart'        
     Format*                              
     **                   `-n'            
                          *Permitted        
                          Values          
                          *               
     *Type*               `boolean'        
     *Default*            `FALSE'         


     Instructs *Note `ndbd': mysql-cluster-programs-ndbd. not to start
     automatically. When this option is used, *Note `ndbd':
     mysql-cluster-programs-ndbd. connects to the management server,
     obtains configuration data from it, and initializes communication
     objects. However, it does not actually start the execution engine
     until specifically requested to do so by the management server.
     This can be accomplished by issuing the proper `START' command in
     the management client (see *Note
     mysql-cluster-mgm-client-commands::).

*Note `ndbd': mysql-cluster-programs-ndbd. generates a set of log files
which are placed in the directory specified by `DataDir' in the
`config.ini' configuration file.

These log files are listed below.  NODE_ID is the node's unique
identifier. Note that NODE_ID represents the node's unique identifier.
For example, `ndb_2_error.log' is the error log generated by the data
node whose node ID is `2'.

   * `ndb_NODE_ID_error.log' is a file containing records of all
     crashes which the referenced *Note `ndbd':
     mysql-cluster-programs-ndbd. process has encountered. Each record
     in this file contains a brief error string and a reference to a
     trace file for this crash. A typical entry in this file might
     appear as shown here:

          Date/Time: Saturday 30 July 2004 - 00:20:01
          Type of error: error
          Message: Internal program error (failed ndbrequire)
          Fault ID: 2341
          Problem data: DbtupFixAlloc.cpp
          Object of reference: DBTUP (Line: 173)
          ProgramName: NDB Kernel
          ProcessID: 14909
          TraceFile: ndb_2_trace.log.2
          ***EOM***

     Listings of possible *Note `ndbd': mysql-cluster-programs-ndbd.
     exit codes and messages generated when a data node process shuts
     down prematurely can be found in `ndbd' Error Messages
     (http://dev.mysql.com/doc/ndbapi/en/ndbd-error-messages.html).

     *Important*:

     _The last entry in the error log file is not necessarily the
     newest one_ (nor is it likely to be). Entries in the error log are
     _not_ listed in chronological order; rather, they correspond to
     the order of the trace files as determined in the
     `ndb_NODE_ID_trace.log.next' file (see below). Error log entries
     are thus overwritten in a cyclical and not sequential fashion.

   * `ndb_NODE_ID_trace.log.TRACE_ID' is a trace file describing
     exactly what happened just before the error occurred. This
     information is useful for analysis by the MySQL Cluster
     development team.

     It is possible to configure the number of these trace files that
     will be created before old files are overwritten. TRACE_ID is a
     number which is incremented for each successive trace file.

   * `ndb_NODE_ID_trace.log.next' is the file that keeps track of the
     next trace file number to be assigned.

   * `ndb_NODE_ID_out.log' is a file containing any data output by the
     *Note `ndbd': mysql-cluster-programs-ndbd. process. This file is
     created only if *Note `ndbd': mysql-cluster-programs-ndbd. is
     started as a daemon, which is the default behavior.

   * `ndb_NODE_ID.pid' is a file containing the process ID of the *Note
     `ndbd': mysql-cluster-programs-ndbd. process when started as a
     daemon.  It also functions as a lock file to avoid the starting of
     nodes with the same identifier.

   * `ndb_NODE_ID_signal.log' is a file used only in debug versions of
     *Note `ndbd': mysql-cluster-programs-ndbd, where it is possible to
     trace all incoming, outgoing, and internal messages with their data
     in the *Note `ndbd': mysql-cluster-programs-ndbd. process.

It is recommended not to use a directory mounted through NFS because in
some environments this can cause problems whereby the lock on the
`.pid' file remains in effect even after the process has terminated.

To start *Note `ndbd': mysql-cluster-programs-ndbd, it may also be
necessary to specify the host name of the management server and the
port on which it is listening. Optionally, one may also specify the
node ID that the process is to use.

     shell> ndbd --connect-string="nodeid=2;host=ndb_mgmd.mysql.com:1186"

See *Note mysql-cluster-connectstring::, for additional information
about this issue.  *Note mysql-cluster-programs-ndbd::, describes other
options for *Note `ndbd': mysql-cluster-programs-ndbd.

When *Note `ndbd': mysql-cluster-programs-ndbd. starts, it actually
initiates two processes. The first of these is called the `angel
process'; its only job is to discover when the execution process has
been completed, and then to restart the *Note `ndbd':
mysql-cluster-programs-ndbd. process if it is configured to do so.
Thus, if you attempt to kill *Note `ndbd': mysql-cluster-programs-ndbd.
using the Unix *Note `kill': kill. command, it is necessary to kill
both processes, beginning with the angel process. The preferred method
of terminating an *Note `ndbd': mysql-cluster-programs-ndbd.  process
is to use the management client and stop the process from there.

The execution process uses one thread for reading, writing, and
scanning data, as well as all other activities. This thread is
implemented asynchronously so that it can easily handle thousands of
concurrent actions. In addition, a watch-dog thread supervises the
execution thread to make sure that it does not hang in an endless loop.
A pool of threads handles file I/O, with each thread able to handle one
open file. Threads can also be used for transporter connections by the
transporters in the *Note `ndbd': mysql-cluster-programs-ndbd. process.
In a multi-processor system performing a large number of operations
(including updates), the *Note `ndbd': mysql-cluster-programs-ndbd.
process can consume up to 2 CPUs if permitted to do so.

For a machine with many CPUs it is possible to use several *Note
`ndbd': mysql-cluster-programs-ndbd. processes which belong to different
node groups; however, such a configuration is still considered
experimental and is not supported for MySQL 5.0 in a production
setting. See *Note mysql-cluster-limitations::.


File: manual.info,  Node: mysql-cluster-programs-ndb-mgmd,  Next: mysql-cluster-programs-ndb-mgm,  Prev: mysql-cluster-programs-ndbd,  Up: mysql-cluster-programs

17.4.3 `ndb_mgmd' -- The MySQL Cluster Management Server Daemon
---------------------------------------------------------------

The management server is the process that reads the cluster
configuration file and distributes this information to all nodes in the
cluster that request it. It also maintains a log of cluster activities.
Management clients can connect to the management server and check the
cluster's status.

The following table includes command options specific to the MySQL
Cluster management node program *Note `ndb_mgmd':
mysql-cluster-programs-ndb-mgmd. Additional descriptions follow the
table. For options common to all MySQL Cluster programs, see *Note
mysql-cluster-program-options-common::.

*`ndb_mgmd' Command Line Options*

Format         Description                          IntroductionDeprecatedRemoved
-c             Specify the cluster configuration                    
               file; in NDB-6.4.0 and later,                        
               needs -reload or -initial to                         
               override configuration cache if                      
               present                                              
-daemon        Run ndb_mgmd in daemon mode                          
               (default)                                            
-interactive   Run ndb_mgmd in interactive mode                     
               (not officially supported in                         
               production; for testing purposes                     
               only)                                                
-mycnf         Read cluster configuration data                      
               from the my.cnf file                                 
-no-nodeid-checksDo not provide any node id checks                    
-nodaemon      Do not run ndb_mgmd as a daemon                      
-print-full-configPrint full configuration and exit    5.0.10          

   *  `--no-nodeid-checks'

     Options for no-nodeid-checks      *Command-Line        `--no-nodeid-checks'        
     Format*                              
                          *Permitted        
                          Values          
                          *               
     *Type*               `boolean'        
     *Default*            `FALSE'         


     Do not perform any checks of node IDs.

   * `--config-file=FILENAME', `-f FILENAME'

     Options for config-file      *Command-Line        `--config-file'        
     Format*                              
     **                   `-f'            
     **                   `-c'            
                          *Permitted        
                          Values          
                          *               
     *Type*               `file           
                          name'           
     *Default*            `./config.ini'        


     Instructs the management server as to which file it should use for
     its configuration file. By default, the management server looks
     for a file named `config.ini' in the same directory as the *Note
     `ndb_mgmd': mysql-cluster-programs-ndb-mgmd. executable; otherwise
     the file name and location must be specified explicitly.

     This option also can be given as `-c FILE_NAME', but this shortcut
     is obsolete and should _not_ be used in new installations.

   *  `--mycnf'

     Options for mycnf      *Command-Line        `--mycnf'        
     Format*                              
                          *Permitted        
                          Values          
                          *               
     *Type*               `boolean'        
     *Default*            `FALSE'         


     Read configuration data from the `my.cnf' file.

   * `--daemon', `-d'

     Options for daemon      *Command-Line        `--daemon'        
     Format*                              
     **                   `-d'            
                          *Permitted        
                          Values          
                          *               
     *Type*               `boolean'        
     *Default*            `TRUE'          


     Instructs *Note `ndb_mgmd': mysql-cluster-programs-ndb-mgmd. to
     start as a daemon process. This is the default behavior.

   *  `--interactive'

     Options for interactive      *Command-Line        `--interactive'        
     Format*                              
                          *Permitted        
                          Values          
                          *               
     *Type*               `boolean'        
     *Default*            `FALSE'         


     Starts *Note `ndb_mgmd': mysql-cluster-programs-ndb-mgmd. in
     interactive mode; that is, an *Note `ndb_mgm':
     mysql-cluster-programs-ndb-mgm. client session is started as soon
     as the management server is running. This option does not start
     any other MySQL Cluster nodes.

   * `--nodaemon'

     Options for nodaemon      *Command-Line        `--nodaemon'        
     Format*                              
                          *Permitted        
                          Values          
                          *               
     *Type*               `boolean'        
     *Default*            `FALSE'         
                          *Permitted        
                          Values          
                          *               
     *Type* (windows)     `boolean'        
     *Default*            `TRUE'          


     Instructs *Note `ndb_mgmd': mysql-cluster-programs-ndb-mgmd. not
     to start as a daemon process.

   * `--print-full-config', `-P'

     Options for print-full-config      *Version Introduced* 5.0.10          
     *Command-Line        `--print-full-config'        
     Format*                              
     **                   `-P'            
                          *Permitted        
                          Values          
                          *               
     *Type*               `boolean'        
     *Default*            `FALSE'         


     Shows extended information regarding the configuration of the
     cluster. With this option on the command line the *Note
     `ndb_mgmd': mysql-cluster-programs-ndb-mgmd. process prints
     information about the cluster setup including an extensive list of
     the cluster configuration sections as well as parameters and their
     values. Normally used together with the `--config-file' (`-f')
     option.

It is not strictly necessary to specify a connectstring when starting
the management server. However, if you are using more than one
management server, a connectstring should be provided and each node in
the cluster should specify its node ID explicitly.

See *Note mysql-cluster-connectstring::, for information about using
connectstrings.  *Note mysql-cluster-programs-ndb-mgmd::, describes
other options for *Note `ndb_mgmd': mysql-cluster-programs-ndb-mgmd.

The following files are created or used by *Note `ndb_mgmd':
mysql-cluster-programs-ndb-mgmd. in its starting directory, and are
placed in the `DataDir' as specified in the `config.ini' configuration
file. In the list that follows, NODE_ID is the unique node identifier.

   * `config.ini' is the configuration file for the cluster as a whole.
     This file is created by the user and read by the management server.
     *Note mysql-cluster-configuration::, discusses how to set up this
     file.

   * `ndb_NODE_ID_cluster.log' is the cluster events log file. Examples
     of such events include checkpoint startup and completion, node
     startup events, node failures, and levels of memory usage. A
     complete listing of cluster events with descriptions may be found
     in *Note mysql-cluster-management::.

     When the size of the cluster log reaches one million bytes, the
     file is renamed to `ndb_NODE_ID_cluster.log.SEQ_ID', where SEQ_ID
     is the sequence number of the cluster log file. (For example: If
     files with the sequence numbers 1, 2, and 3 already exist, the
     next log file is named using the number `4'.)

   * `ndb_NODE_ID_out.log' is the file used for `stdout' and `stderr'
     when running the management server as a daemon.

   * `ndb_NODE_ID.pid' is the process ID file used when running the
     management server as a daemon.


File: manual.info,  Node: mysql-cluster-programs-ndb-mgm,  Next: mysql-cluster-programs-ndb-config,  Prev: mysql-cluster-programs-ndb-mgmd,  Up: mysql-cluster-programs

17.4.4 `ndb_mgm' -- The MySQL Cluster Management Client
-------------------------------------------------------

The *Note `ndb_mgm': mysql-cluster-programs-ndb-mgm. management client
process is actually not needed to run the cluster. Its value lies in
providing a set of commands for checking the cluster's status, starting
backups, and performing other administrative functions. The management
client accesses the management server using a C API. Advanced users can
also employ this API for programming dedicated management processes to
perform tasks similar to those performed by *Note `ndb_mgm':
mysql-cluster-programs-ndb-mgm.

To start the management client, it is necessary to supply the host name
and port number of the management server:

     shell> ndb_mgm [HOST_NAME [PORT_NUM]]

For example:

     shell> ndb_mgm ndb_mgmd.mysql.com 1186

The default host name and port number are `localhost' and 1186,
respectively.

The following table includes command options specific to the MySQL
Cluster management client program *Note `ndb_mgm':
mysql-cluster-programs-ndb-mgm. Additional descriptions follow the
table. For options common to all MySQL Cluster programs, see *Note
mysql-cluster-program-options-common::.

*`ndb_mgm' Command Line Options*

Format         Description                          IntroductionDeprecatedRemoved
-execute=name  Execute command and exit                             
-try-reconnect=#Specify number of tries for                          
               connecting to ndb_mgmd (0 =                          
               infinite)                                            

   * `--execute=`command'', `-e `command''

     Options for execute      *Command-Line        `--execute=name'        
     Format*                              
     **                   `-e'            


     This option can be used to send a command to the MySQL Cluster
     management client from the system shell. For example, either of
     the following:

          shell> ndb_mgm -e "SHOW"

     or

          shell> ndb_mgm --execute="SHOW"

     is equivalent to

          ndb_mgm> SHOW

     This is analogous to how the `--execute' or `-e' option works with
     the *Note `mysql': mysql. command-line client. See *Note
     command-line-options::.

     *Note*:

     If the management client command to be passed using this option
     contains any space characters, then the command _must_ be enclosed
     in quotation marks. Either single or double quotation marks may be
     used. If the management client command contains no space
     characters, the quotation marks are optional.

   *  `--try-reconnect=NUMBER'

     Options for try-reconnect      *Command-Line        `--try-reconnect=#'        
     Format*                              
     **                   `-t'            
                          *Permitted        
                          Values          
                          *               
     *Type*               `boolean'        
     *Default*            `TRUE'          


     If the connection to the management server is broken, the node
     tries to reconnect to it every 5 seconds until it succeeds. By
     using this option, it is possible to limit the number of attempts
     to NUMBER before giving up and reporting an error instead.

Additional information about using *Note `ndb_mgm':
mysql-cluster-programs-ndb-mgm.  can be found in *Note
mysql-cluster-mgm-client-commands::.


File: manual.info,  Node: mysql-cluster-programs-ndb-config,  Next: mysql-cluster-programs-ndb-cpcd,  Prev: mysql-cluster-programs-ndb-mgm,  Up: mysql-cluster-programs

17.4.5 `ndb_config' -- Extract MySQL Cluster Configuration Information
----------------------------------------------------------------------

This tool extracts configuration information for data nodes, SQL nodes,
and API nodes from a cluster management node (and possibly its
`config.ini' file).

The following table includes command options specific to the MySQL
Cluster program *Note `ndb_config': mysql-cluster-programs-ndb-config.
Additional descriptions follow the table. For options common to all
MySQL Cluster programs, see *Note
mysql-cluster-program-options-common::.

*`ndb_config' Command Line Options*

Format         Description                          IntroductionDeprecatedRemoved
-config-file=pathSet the path to config.ini file                      
-fields=string Field separator                                      
-host=name     Specify host                                         
-mycnf         Read configuration data from my.cnf                  
               file                                                 
-nodeid        Get configuration of node with this                  
               ID                                                   
-nodes         Print node information (DB section)                  
               only.                                                
-c             Short form for -ndb-connectstring    5.0.33          
-query=string  One or more query options                            
               (attributes)                                         
-rows=string   Row separator                                        
-type=name     Specify node type                                    

   *  `--usage', `--help', or `-?'

     Options for help      *Command-Line        `--help'        
     Format*                              
     **                   `--usage'        
     **                   `-?'            


     Causes *Note `ndb_config': mysql-cluster-programs-ndb-config. to
     print a list of available options, and then exit.

   *  `--version', `-V'

     Options for version      *Command-Line        `--version'        
     Format*                              
     **                   `-V'            


     Causes *Note `ndb_config': mysql-cluster-programs-ndb-config. to
     print a version information string, and then exit.

   *  `--ndb-connectstring=CONNECT_STRING'

     Specifies the connectstring to use in connecting to the management
     server. The format for the connectstring is the same as described
     in *Note mysql-cluster-connectstring::, and defaults to
     `localhost:1186'.

     The use of `-c' as a short version for this option is supported
     for *Note `ndb_config': mysql-cluster-programs-ndb-config.
     beginning with MySQL 5.0.29.

   *  `--config-file=PATH-TO-FILE'

     Options for config-file      *Command-Line        `--config-file=path'        
     Format*                              
                          *Permitted        
                          Values          
                          *               
     *Type*               `file           
                          name'           
     *Default*            `'              


     Gives the path to the management server's configuration file
     (`config.ini'). This may be a relative or absolute path. If the
     management node resides on a different host from the one on which
     *Note `ndb_config': mysql-cluster-programs-ndb-config. is invoked,
     then an absolute path must be used.

   *  `--mycnf'

     Options for mycnf      *Command-Line        `--mycnf'        
     Format*                              
                          *Permitted        
                          Values          
                          *               
     *Type*               `boolean'        
     *Default*            `FALSE'         


     Read configuration data from the `my.cnf' file.

   *  `--query=QUERY-OPTIONS', `-q' QUERY-OPTIONS

     Options for query      *Command-Line        `--query=string'        
     Format*                              
     **                   `-q'            
                          *Permitted        
                          Values          
                          *               
     *Type*               `string'        
     *Default*            `'              


     This is a comma-delimited list of _query options_--that is, a list
     of one or more node attributes to be returned. These include `id'
     (node ID), type (node type--that is, `ndbd', `mysqld', or
     `ndb_mgmd'), and any configuration parameters whose values are to
     be obtained.

     For example,

     `--query=id,type,indexmemory,datamemory' would return the node ID,
     node type, `DataMemory', and `IndexMemory' for each node.

     *Note*:

     If a given parameter is not applicable to a certain type of node,
     than an empty string is returned for the corresponding value. See
     the examples later in this section for more information.

   *  `--host=HOSTNAME'

     Options for host      *Command-Line        `--host=name'        
     Format*                              
                          *Permitted        
                          Values          
                          *               
     *Type*               `string'        
     *Default*            `'              


     Specifies the host name of the node for which configuration
     information is to be obtained.

     *Note*:

     While the hostname `localhost' usually resolves to the IP address
     `127.0.0.1', this may not necessarily be true for all operating
     platforms and configurations. This means that it is possible, when
     `localhost' is used in `config.ini', for *Note `ndb_config
     `--host=localhost'': mysql-cluster-programs-ndb-config. to fail if
     *Note `ndb_config': mysql-cluster-programs-ndb-config. is run on a
     different host where `localhost' resolves to a different address
     (for example, on some versions of SUSE Linux, this is
     `127.0.0.2'). In general, for best results, you should use numeric
     IP addresses for all MySQL Clustewr configuration values relating
     to hosts, or verify that all MySQL Cluster hosts handle
     `localhost' in the same fashion.

   *  `--id=NODE_ID'

     `--nodeid=NODE_ID'

     Used to specify the node ID of the node for which configuration
     information is to be obtained.

   *  `--nodes'

     Options for nodes      *Command-Line        `--nodes'        
     Format*                              
                          *Permitted        
                          Values          
                          *               
     *Type*               `boolean'        
     *Default*            `FALSE'         


     (Tells *Note `ndb_config': mysql-cluster-programs-ndb-config. to
     print information from parameters defined in `[ndbd]' sections
     only. Currently, using this option has no affect, since these are
     the only values checked, but it may become possible in future to
     query parameters set in `[tcp]' and other sections of cluster
     configuration files.)

   *  `--connections'

     This option (not listed in the table) is present but has no affect
     in MySQL 5.0. It is reserved for use in a future version of MySQL
     Cluster.

   *  `--type=NODE_TYPE'

     Options for type      *Command-Line        `--type=name'        
     Format*                              
                          *Permitted        
                          Values          
                          *               
     *Type*               `enumeration'        
     *Default*            `'              
     *Valid Values*       `ndbd'          
                          `mysqld'        
                          `ndb_mgmd'        


     Filters results so that only configuration values applying to
     nodes of the specified NODE_TYPE (`ndbd', `mysqld', or `ndb_mgmd')
     are returned.

   *  `--fields=DELIMITER', `-f' DELIMITER

     Options for fields      *Command-Line        `--fields=string'        
     Format*                              
     **                   `-f'            
                          *Permitted        
                          Values          
                          *               
     *Type*               `string'        
     *Default*            `'              


     Specifies a DELIMITER string used to separate the fields in the
     result. The default is ``,'' (the comma character).

     *Note*:

     If the DELIMITER contains spaces or escapes (such as `\n' for the
     linefeed character), then it must be quoted.

   *  `--rows=SEPARATOR', `-r' SEPARATOR

     Options for rows      *Command-Line        `--rows=string'        
     Format*                              
     **                   `-r'            
                          *Permitted        
                          Values          
                          *               
     *Type*               `string'        
     *Default*            `'              


     Specifies a SEPARATOR string used to separate the rows in the
     result. The default is a space character.

     *Note*:

     If the SEPARATOR contains spaces or escapes (such as `\n' for the
     linefeed character), then it must be quoted.

*Examples*:

  1. To obtain the node ID and type of each node in the cluster:

          shell> ./ndb_config --query=id,type --fields=':' --rows='\n'
          1:ndbd
          2:ndbd
          3:ndbd
          4:ndbd
          5:ndb_mgmd
          6:mysqld
          7:mysqld
          8:mysqld
          9:mysqld

     In this example, we used the `--fields' options to separate the ID
     and type of each node with a colon character (`:'), and the
     `--rows' options to place the values for each node on a new line
     in the output.

  2. To produce a connectstring that can be used by data, SQL, and API
     nodes to connect to the management server:

          shell> ./ndb_config --config-file=usr/local/mysql/cluster-data/config.ini --query=hostname,portnumber --fields=: --rows=, --type=ndb_mgmd
          192.168.0.179:1186

  3. This invocation of *Note `ndb_config':
     mysql-cluster-programs-ndb-config. checks only data nodes (using
     the `--type' option), and shows the values for each node's ID and
     host name, and its `DataMemory', `IndexMemory', and `DataDir'
     parameters:

          shell> ./ndb_config --type=ndbd --query=id,host,datamemory,indexmemory,datadir -f ' : ' -r '\n'
          1 : 192.168.0.193 : 83886080 : 18874368 : /usr/local/mysql/cluster-data
          2 : 192.168.0.112 : 83886080 : 18874368 : /usr/local/mysql/cluster-data
          3 : 192.168.0.176 : 83886080 : 18874368 : /usr/local/mysql/cluster-data
          4 : 192.168.0.119 : 83886080 : 18874368 : /usr/local/mysql/cluster-data

     In this example, we used the short options `-f' and `-r' for
     setting the field delimiter and row separator, respectively.

  4. To exclude results from any host except one in particular, use the
     `--host' option:

          shell> ./ndb_config --host=192.168.0.176 -f : -r '\n' -q id,type
          3:ndbd
          5:ndb_mgmd

     In this example, we also used the short form `-q' to determine the
     attributes to be queried.

     Similarly, you can limit results to a node with a specific ID
     using the `--id' or `--nodeid' option.


File: manual.info,  Node: mysql-cluster-programs-ndb-cpcd,  Next: mysql-cluster-programs-ndb-delete-all,  Prev: mysql-cluster-programs-ndb-config,  Up: mysql-cluster-programs

17.4.6 `ndb_cpcd' -- Automate Testing for NDB Development
---------------------------------------------------------

This utility is found in the `libexec' directory. It is part of an
internal automated test framework used in testing and debugging MySQL
Cluster. Because it can control processes on remote systems, it is not
advisable to use *Note `ndb_cpcd': mysql-cluster-programs-ndb-cpcd. in
a production cluster.

The source files for *Note `ndb_cpcd': mysql-cluster-programs-ndb-cpcd.
may be found in the directory `storage/ndb/src/cw/cpcd', in the MySQL
source tree.


File: manual.info,  Node: mysql-cluster-programs-ndb-delete-all,  Next: mysql-cluster-programs-ndb-desc,  Prev: mysql-cluster-programs-ndb-cpcd,  Up: mysql-cluster-programs

17.4.7 `ndb_delete_all' -- Delete All Rows from an NDB Table
------------------------------------------------------------

*Note `ndb_delete_all': mysql-cluster-programs-ndb-delete-all. deletes
all rows from the given *Note `NDB': mysql-cluster. table. In some
cases, this can be much faster than *Note `DELETE': delete. or even
*Note `TRUNCATE TABLE': truncate-table.

*Usage*:

     ndb_delete_all -c CONNECT_STRING TBL_NAME -d DB_NAME

This deletes all rows from the table named TBL_NAME in the database
named DB_NAME. It is exactly equivalent to executing `TRUNCATE
DB_NAME.TBL_NAME' in MySQL.

*Additional Options*:

   * `--transactional', `-t'

     Use of this option causes the delete operation to be performed as
     a single transaction.

     *Warning*:

     With very large tables, using this option may cause the number of
     operations available to the cluster to be exceeded.


File: manual.info,  Node: mysql-cluster-programs-ndb-desc,  Next: mysql-cluster-programs-ndb-drop-index,  Prev: mysql-cluster-programs-ndb-delete-all,  Up: mysql-cluster-programs

17.4.8 `ndb_desc' -- Describe NDB Tables
----------------------------------------

*Note `ndb_desc': mysql-cluster-programs-ndb-desc. provides a detailed
description of one or more *Note `NDB': mysql-cluster. tables.

*Usage*:

     ndb_desc -c CONNECT_STRING TBL_NAME -d DB_NAME [-p]

*Sample Output*:

MySQL table creation and population statements:

     USE test;

     CREATE TABLE fish (
         id INT(11) NOT NULL AUTO_INCREMENT,
         name VARCHAR(20),

         PRIMARY KEY pk (id),
         UNIQUE KEY uk (name)
     ) ENGINE=NDBCLUSTER;

     INSERT INTO fish VALUES
         ('','guppy'), ('','tuna'), ('','shark'),
         ('','manta ray'), ('','grouper'), ('','puffer');

Output from *Note `ndb_desc': mysql-cluster-programs-ndb-desc.:

     shell> ./ndb_desc -c localhost fish -d test -p
     -- fish --
     Version: 16777221
     Fragment type: 5
     K Value: 6
     Min load factor: 78
     Max load factor: 80
     Temporary table: no
     Number of attributes: 2
     Number of primary keys: 1
     Length of frm data: 268
     Row Checksum: 1
     Row GCI: 1
     TableStatus: Retrieved
     -- Attributes --
     id Int PRIMARY KEY DISTRIBUTION KEY AT=FIXED ST=MEMORY
     name Varchar(20;latin1_swedish_ci) NULL AT=SHORT_VAR ST=MEMORY

     -- Indexes --
     PRIMARY KEY(id) - UniqueHashIndex
     uk(name) - OrderedIndex
     PRIMARY(id) - OrderedIndex
     uk$unique(name) - UniqueHashIndex

     -- Per partition info --
     Partition  Row count  Commit count  Frag fixed memory  Frag varsized memory
     2          2          2             65536              327680
     1          2          2             65536              327680
     3          2          2             65536              327680

     NDBT_ProgramExit: 0 - OK

Information about multiple tables can be obtained in a single
invocation of *Note `ndb_desc': mysql-cluster-programs-ndb-desc. by
using their names, separated by spaces. All of the tables must be in the
same database.

*Additional Options*:

   *  `--extra-partition-info', `-p'

     Prints additional information about the table's partitions.


File: manual.info,  Node: mysql-cluster-programs-ndb-drop-index,  Next: mysql-cluster-programs-ndb-drop-table,  Prev: mysql-cluster-programs-ndb-desc,  Up: mysql-cluster-programs

17.4.9 `ndb_drop_index' -- Drop Index from an NDB Table
-------------------------------------------------------

*Note `ndb_drop_index': mysql-cluster-programs-ndb-drop-index. drops
the specified index from an *Note `NDB': mysql-cluster. table. _It is
recommended that you use this utility only as an example for writing
NDB API applications_--see the Warning later in this section for
details.

*Usage*:

     ndb_drop_index -c CONNECT_STRING TABLE_NAME INDEX -d DB_NAME

The statement shown above drops the index named INDEX from the TABLE in
the DATABASE.

*Additional Options*: None that are specific to this application.

*Warning*:

_Operations performed on Cluster table indexes using the NDB API are
not visible to MySQL and make the table unusable by a MySQL server_. If
you use this program to drop an index, then try to access the table from
an SQL node, an error results, as shown here:

     shell> ./ndb_drop_index -c localhost dogs ix -d ctest1
     Dropping index dogs/idx...OK

     NDBT_ProgramExit: 0 - OK

     shell> ./mysql -u jon -p ctest1
     Enter password: *******
     Reading table information for completion of table and column names
     You can turn off this feature to get a quicker startup with -A

     Welcome to the MySQL monitor.  Commands end with ; or \g.
     Your MySQL connection id is 7 to server version: 5.0.95

     Type 'help;' or '\h' for help. Type '\c' to clear the buffer.

     mysql> SHOW TABLES;
     +------------------+
     | Tables_in_ctest1 |
     +------------------+
     | a                |
     | bt1              |
     | bt2              |
     | dogs             |
     | employees        |
     | fish             |
     +------------------+
     6 rows in set (0.00 sec)

     mysql> SELECT * FROM dogs;
     `ERROR 1296 (HY000): Got error 4243 'Index not found' from NDBCLUSTER'

In such a case, your _only_ option for making the table available to
MySQL again is to drop the table and re-create it. You can use either
the SQL statement*Note `DROP TABLE': drop-table. or the *Note
`ndb_drop_table': mysql-cluster-programs-ndb-drop-table. utility (see
*Note mysql-cluster-programs-ndb-drop-table::) to drop the table.


File: manual.info,  Node: mysql-cluster-programs-ndb-drop-table,  Next: mysql-cluster-programs-ndb-error-reporter,  Prev: mysql-cluster-programs-ndb-drop-index,  Up: mysql-cluster-programs

17.4.10 `ndb_drop_table' -- Drop an NDB Table
---------------------------------------------

*Note `ndb_drop_table': mysql-cluster-programs-ndb-drop-table. drops
the specified *Note `NDB': mysql-cluster. table. (If you try to use
this on a table created with a storage engine other than NDB, it fails
with the error `723: No such table exists'.) This operation is
extremely fast--in some cases, it can be an order of magnitude faster
than using *Note `DROP TABLE': drop-table. on an *Note `NDB':
mysql-cluster. table from MySQL.

*Usage*:

     ndb_drop_table -c CONNECT_STRING TBL_NAME -d DB_NAME

*Additional Options*: None.


File: manual.info,  Node: mysql-cluster-programs-ndb-error-reporter,  Next: mysql-cluster-programs-ndb-print-backup-file,  Prev: mysql-cluster-programs-ndb-drop-table,  Up: mysql-cluster-programs

17.4.11 `ndb_error_reporter' -- NDB Error-Reporting Utility
-----------------------------------------------------------

*Note `ndb_error_reporter': mysql-cluster-programs-ndb-error-reporter.
creates an archive from data node and management node log files that
can be used to help diagnose bugs or other problems with a cluster.
_It is highly recommended that you make use of this utility when filing
reports of bugs in MySQL Cluster_.

The following table includes command options specific to the MySQL
Cluster program *Note `ndb_error_reporter':
mysql-cluster-programs-ndb-error-reporter.  Additional descriptions
follow the table. For options common to all MySQL Cluster programs, see
*Note mysql-cluster-program-options-common::.

*`ndb_error_reporter' Command Line Options*

Format         Description                          IntroductionDeprecatedRemoved
-fs            Include file system data in error                    
               report; can use a large amount  of                   
               disk space                                           

*Usage*:

     ndb_error_reporter PATH/TO/CONFIG-FILE [USERNAME] [--fs]

This utility is intended for use on a management node host, and
requires the path to the management host configuration file
(`config.ini'). Optionally, you can supply the name of a user that is
able to access the cluster's data nodes using SSH, to copy the data
node log files.  ndb_error_reporter then includes all of these files in
archive that is created in the same directory in which it is run. The
archive is named `ndb_error_report_YYYYMMDDHHMMSS.tar.bz2', where
YYYYMMDDHHMMSS is a datetime string.

If the `--fs' is used, then the data node file systems are also copied
to the management host and included in the archive that is produced by
this script. As data node file systems can be extremely large even
after being compressed, we ask that you please do _not_ send archives
created using this option to Oracle unless you are specifically
requested to do so.

Options for fs *Command-Line Format*  `--fs'          
                       *Permitted        
                       Values          
                       *               
*Type*                 `boolean'        
*Default*              `FALSE'         



File: manual.info,  Node: mysql-cluster-programs-ndb-print-backup-file,  Next: mysql-cluster-programs-ndb-print-schema-file,  Prev: mysql-cluster-programs-ndb-error-reporter,  Up: mysql-cluster-programs

17.4.12 `ndb_print_backup_file' -- Print NDB Backup File Contents
-----------------------------------------------------------------

*Note `ndb_print_backup_file':
mysql-cluster-programs-ndb-print-backup-file. obtains diagnostic
information from a cluster backup file.

*Usage*:

     ndb_print_backup_file FILE_NAME

FILE_NAME is the name of a cluster backup file. This can be any of the
files (`.Data', `.ctl', or `.log' file) found in a cluster backup
directory. These files are found in the data node's backup directory
under the subdirectory `BACKUP-#', where # is the sequence number for
the backup. For more information about cluster backup files and their
contents, see *Note mysql-cluster-backup-concepts::.

Like *Note `ndb_print_schema_file':
mysql-cluster-programs-ndb-print-schema-file. and *Note
`ndb_print_sys_file': mysql-cluster-programs-ndb-print-sys-file. (and
unlike most of the other *Note `NDB': mysql-cluster. utilities that are
intended to be run on a management server host or to connect to a
management server) *Note `ndb_print_backup_file':
mysql-cluster-programs-ndb-print-backup-file. must be run on a cluster
data node, since it accesses the data node file system directly.
Because it does not make use of the management server, this utility can
be used when the management server is not running, and even when the
cluster has been completely shut down.

*Additional Options*: None.


File: manual.info,  Node: mysql-cluster-programs-ndb-print-schema-file,  Next: mysql-cluster-programs-ndb-print-sys-file,  Prev: mysql-cluster-programs-ndb-print-backup-file,  Up: mysql-cluster-programs

17.4.13 `ndb_print_schema_file' -- Print NDB Schema File Contents
-----------------------------------------------------------------

*Note `ndb_print_schema_file':
mysql-cluster-programs-ndb-print-schema-file. obtains diagnostic
information from a cluster schema file.

*Usage*:

     ndb_print_schema_file FILE_NAME

FILE_NAME is the name of a cluster schema file. For more information
about cluster schema files, see Cluster Data Node `FileSystemDir' Files
(http://dev.mysql.com/doc/ndbapi/en/ndb-internals-ndbd-filesystemdir-files.html).

Like *Note `ndb_print_backup_file':
mysql-cluster-programs-ndb-print-backup-file. and *Note
`ndb_print_sys_file': mysql-cluster-programs-ndb-print-sys-file. (and
unlike most of the other *Note `NDB': mysql-cluster. utilities that are
intended to be run on a management server host or to connect to a
management server) `ndb_schema_backup_file' must be run on a cluster
data node, since it accesses the data node file system directly.
Because it does not make use of the management server, this utility can
be used when the management server is not running, and even when the
cluster has been completely shut down.

*Additional Options*: None.


File: manual.info,  Node: mysql-cluster-programs-ndb-print-sys-file,  Next: mysql-cluster-programs-ndb-restore,  Prev: mysql-cluster-programs-ndb-print-schema-file,  Up: mysql-cluster-programs

17.4.14 `ndb_print_sys_file' -- Print NDB System File Contents
--------------------------------------------------------------

*Note `ndb_print_sys_file': mysql-cluster-programs-ndb-print-sys-file.
obtains diagnostic information from a MySQL Cluster system file.

*Usage*:

     ndb_print_sys_file FILE_NAME

FILE_NAME is the name of a cluster system file (sysfile). Cluster
system files are located in a data node's data directory (`DataDir');
the path under this directory to system files matches the pattern
`ndb_#_fs/D#/DBDIH/P#.sysfile'.  In each case, the # represents a
number (not necessarily the same number). For more information, see
Cluster Data Node `FileSystemDir' Files
(http://dev.mysql.com/doc/ndbapi/en/ndb-internals-ndbd-filesystemdir-files.html).

Like *Note `ndb_print_backup_file':
mysql-cluster-programs-ndb-print-backup-file. and *Note
`ndb_print_schema_file': mysql-cluster-programs-ndb-print-schema-file.
(and unlike most of the other *Note `NDB': mysql-cluster. utilities
that are intended to be run on a management server host or to connect
to a management server) *Note `ndb_print_backup_file':
mysql-cluster-programs-ndb-print-backup-file. must be run on a cluster
data node, since it accesses the data node file system directly.
Because it does not make use of the management server, this utility can
be used when the management server is not running, and even when the
cluster has been completely shut down.

*Additional Options*: None.


File: manual.info,  Node: mysql-cluster-programs-ndb-restore,  Next: mysql-cluster-programs-ndb-select-all,  Prev: mysql-cluster-programs-ndb-print-sys-file,  Up: mysql-cluster-programs

17.4.15 `ndb_restore' -- Restore a MySQL Cluster Backup
-------------------------------------------------------

The cluster restoration program is implemented as a separate
command-line utility *Note `ndb_restore':
mysql-cluster-programs-ndb-restore, which can normally be found in the
MySQL `bin' directory. This program reads the files created as a result
of the backup and inserts the stored information into the database.

*Note `ndb_restore': mysql-cluster-programs-ndb-restore. must be
executed once for each of the backup files that were created by the
`START BACKUP' command used to create the backup (see *Note
mysql-cluster-backup-using-management-client::).  This is equal to the
number of data nodes in the cluster at the time that the backup was
created.

*Note*:

Before using *Note `ndb_restore': mysql-cluster-programs-ndb-restore,
it is recommended that the cluster be running in single user mode,
unless you are restoring multiple data nodes in parallel.  See *Note
mysql-cluster-single-user-mode::, for more information about single
user mode.

The following table includes options that are specific to the MySQL
Cluster native backup restoration program *Note `ndb_restore':
mysql-cluster-programs-ndb-restore. Additional descriptions follow the
table. For options common to all MySQL Cluster programs, see *Note
mysql-cluster-program-options-common::.

*`ndb_restore' Command Line Options*

Format         Description                          IntroductionDeprecatedRemoved
-append        Append data to a tab-delimited file  5.0.40          
-backup_path=pathPath to backup files directory       5.0.38          
-backupid=#    Restore from the backup with the                     
               given ID                                             
-connect       Same as connectstring                                
-dont_ignore_systab_0Do not ignore system table during                    
               restore. Experimental only; not                      
               for production use                                   
-fields-enclosed-by=charFields are enclosed with the         5.0.40          
               indicated character                                  
-fields-optionally-enclosed-byFields are optionally enclosed with  5.0.40          
               the indicated character                              
-fields-terminated-by=charFields are terminated by the         5.0.40          
               indicated character                                  
-hex           Print binary types in hexadecimal    5.0.40          
               format                                               
-lines-terminated-by=charLines are terminated by the          5.0.40          
               indicated character                                  
-nodeid=#      Back up files from node with this ID                 
-parallelism=# Number of parallel transactions to                   
               use while restoring data                             
-print         Print metadata, data and log to                      
               stdout (equivalent to -print_meta                    
               -print_data -print_log)                              
-print_data    Print data to stdout                                 
-print_log     Print to stdout                                      
-print_metadataPrint metadata to stdout                             
-restore_data  Restore table data and logs into                     
               NDB Cluster using the NDB API                        
-restore_meta  Restore metadata to NDB Cluster                      
               using the NDB API                                    
-tab=path      Creates a tab-separated .txt file    5.0.40          
               for each table in the given path                     
-verbose=#     Level of verbosity in output                         

Typical options for this utility are shown here:

     ndb_restore [-c CONNECTSTRING] -n NODE_ID [-m] -b BACKUP_ID \
         -r --backup_path=/PATH/TO/BACKUP/FILES

The `-c' option is used to specify a connectstring which tells
`ndb_restore' where to locate the cluster management server. (See *Note
mysql-cluster-connectstring::, for information on connectstrings.) If
this option is not used, then *Note `ndb_restore':
mysql-cluster-programs-ndb-restore. attempts to connect to a management
server on `localhost:1186'. This utility acts as a cluster API node,
and so requires a free connection `slot' to connect to the cluster
management server. This means that there must be at least one `[api]'
or `[mysqld]' section that can be used by it in the cluster
`config.ini' file. It is a good idea to keep at least one empty `[api]'
or `[mysqld]' section in `config.ini' that is not being used for a
MySQL server or other application for this reason (see *Note
mysql-cluster-api-definition::).

You can verify that *Note `ndb_restore':
mysql-cluster-programs-ndb-restore. is connected to the cluster by
using the `SHOW' command in the *Note `ndb_mgm':
mysql-cluster-programs-ndb-mgm. management client.  You can also
accomplish this from a system shell, as shown here:

     shell> ndb_mgm -e "SHOW"

`-n' is used to specify the node ID of the data node on which the
backups were taken.

The first time you run the *Note `ndb_restore':
mysql-cluster-programs-ndb-restore.  restoration program, you also need
to restore the metadata. In other words, you must re-create the
database tables--this can be done by running it with the `-m' option.
Note that the cluster should have an empty database when starting to
restore a backup. (In other words, you should start *Note `ndbd':
mysql-cluster-programs-ndbd. with `--initial' prior to performing the
restore.)

The `-b' option is used to specify the ID or sequence number of the
backup, and is the same number shown by the management client in the
`Backup BACKUP_ID completed' message displayed upon completion of a
backup. (See *Note mysql-cluster-backup-using-management-client::.)

*Important*:

When restoring cluster backups, you must be sure to restore all data
nodes from backups having the same backup ID. Using files from
different backups will at best result in restoring the cluster to an
inconsistent state, and may fail altogether.

The path to the backup directory is required; this is supplied to *Note
`ndb_restore': mysql-cluster-programs-ndb-restore. using the
`--backup_path' option, and must include the subdirectory corresponding
to the ID backup of the backup to be restored. For example, if the data
node's `DataDir' is `/var/lib/mysql-cluster', then the backup directory
is `/var/lib/mysql-cluster/BACKUP', and the backup files for the backup
with the ID 3 can be found in `/var/lib/mysql-cluster/BACKUP/BACKUP-3'.
The path may be absolute or relative to the directory in which the
*Note `ndb_restore': mysql-cluster-programs-ndb-restore. executable is
located, and may be optionally prefixed with `backup_path='.

*Note*:

Previous to MySQL 5.0.38, the path to the backup directory was
specified as shown here, with `backup_path=' being optional:

     [backup_path=]/PATH/TO/BACKUP/FILES

Beginning with MySQL 5.0.38, this syntax changed to
`--backup_path=/PATH/TO/BACKUP/FILES', to conform more closely with
options used by other MySQL programs; `--backup_id' is required, and
there is no short form for this option.

It is possible to restore a backup to a database with a different
configuration than it was created from. For example, suppose that a
backup with backup ID `12', created in a cluster with two database
nodes having the node IDs `2' and `3', is to be restored to a cluster
with four nodes. Then *Note `ndb_restore':
mysql-cluster-programs-ndb-restore. must be run twice--once for each
database node in the cluster where the backup was taken. However, *Note
`ndb_restore': mysql-cluster-programs-ndb-restore. cannot always
restore backups made from a cluster running one version of MySQL to a
cluster running a different MySQL version. See *Note
mysql-cluster-upgrade-downgrade::, for more information.

*Important*:

It is not possible to restore a backup made from a newer version of
MySQL Cluster using an older version of *Note `ndb_restore':
mysql-cluster-programs-ndb-restore. You can restore a backup made from
a newer version of MySQL to an older cluster, but you must use a copy
of *Note `ndb_restore': mysql-cluster-programs-ndb-restore. from the
newer MySQL Cluster version to do so.

For example, to restore a cluster backup taken from a cluster running
MySQL 5.0.45 to a cluster running MySQL Cluster 5.0.41, you must use a
copy of *Note `ndb_restore': mysql-cluster-programs-ndb-restore. from
the 5.0.45 distribution.

For more rapid restoration, the data may be restored in parallel,
provided that there is a sufficient number of cluster connections
available. That is, when restoring to multiple nodes in parallel, you
must have an `[api]' or `[mysqld]' section in the cluster `config.ini'
file available for each concurrent *Note `ndb_restore':
mysql-cluster-programs-ndb-restore.  process. However, the data files
must always be applied before the logs.

`--dont_ignore_systab_0'

Normally, when restoring table data and metadata, *Note `ndb_restore':
mysql-cluster-programs-ndb-restore. ignores the copy of the *Note
`NDB': mysql-cluster. system table that is present in the backup.
`--dont_ignore_systab_0' causes the system table to be restored. _This
option is intended for experimental and development use only, and is not
recommended in a production environment_.

`--parallelism=#', `-p'

Determines the maximum number of parallel transactions that *Note
`ndb_restore': mysql-cluster-programs-ndb-restore. tries to use. By
default, this is 128; the minimum is 1, and the maximum is 1024.

`--restore_data' causes *Note `ndb_restore':
mysql-cluster-programs-ndb-restore. to output *Note `NDB':
mysql-cluster. table data and logs.

This option causes *Note `ndb_restore':
mysql-cluster-programs-ndb-restore. to print *Note `NDB':
mysql-cluster. table metadata.

`--print_metadata'

This option causes *Note `ndb_restore':
mysql-cluster-programs-ndb-restore. to print all metadata to `stdout'.

`--print_log'

The `--print_log' option causes *Note `ndb_restore':
mysql-cluster-programs-ndb-restore. to output its log to `stdout'.

`--print'

Causes *Note `ndb_restore': mysql-cluster-programs-ndb-restore. to
print all data, metadata, and logs to `stdout'. Equivalent to using the
`--print_data', `--print_metadata', and `--print_log' options together.

The `--print_data' option causes *Note `ndb_restore':
mysql-cluster-programs-ndb-restore. to direct its output to `stdout'.

*Note `TEXT': blob. and *Note `BLOB': blob. column values are always
truncated to the first 256 bytes in the output; this cannot currrently
be overridden when using `--print_data'.

Beginning with MySQL 5.0.40, several additional options are available
for use with the `--print_data' option in generating data dumps, either
to `stdout', or to a file. These are similar to some of the options
used with *Note `mysqldump': mysqldump, and are shown in the following
list:

   *  `--tab', `-T'

     Options for tab      *Version Introduced* 5.0.40          
     *Command-Line        `--tab=path'        
     Format*                              
     **                   `-T'            


     This option causes `--print_data' to create dump files, one per
     table, each named `TBL_NAME.txt'.  It requires as its argument the
     path to the directory where the files should be saved; use `.' for
     the current directory.

   *  `--fields-enclosed-by=STRING'

     Options for fields-enclosed-by      *Version Introduced* 5.0.40          
     *Command-Line        `--fields-enclosed-by=char'        
     Format*                              
                          *Permitted        
                          Values          
                          *               
     *Type*               `string'        
     *Default*            `'              


     Each column values are enclosed by the string passed to this
     option (regardless of data type; see next item).

   *  `--fields-optionally-enclosed-by=STRING'

     Options for fields-optionally-enclosed-by      *Version Introduced* 5.0.40          
     *Command-Line        `--fields-optionally-enclosed-by'        
     Format*                              
                          *Permitted        
                          Values          
                          *               
     *Type*               `string'        
     *Default*            `'              


     The string passed to this option is used to enclose column values
     containing character data (such as *Note `CHAR': char, *Note
     `VARCHAR': char, *Note `BINARY': binary-varbinary, *Note `TEXT':
     blob, or *Note `ENUM': enum.).

   *  `--fields-terminated-by=STRING'

     Options for fields-terminated-by      *Version Introduced* 5.0.40          
     *Command-Line        `--fields-terminated-by=char'        
     Format*                              
                          *Permitted        
                          Values          
                          *               
     *Type*               `string'        
     *Default*            `\t             
                          (tab)'          


     The string passed to this option is used to separate column
     values. The default value is a tab character (`\t').

   *  `--hex'

     Options for hex      *Version Introduced* 5.0.40          
     *Command-Line        `--hex'         
     Format*                              


     If this option is used, all binary values are output in
     hexadecimal format.

   *  `--fields-terminated-by=STRING'

     Options for fields-terminated-by      *Version Introduced* 5.0.40          
     *Command-Line        `--fields-terminated-by=char'        
     Format*                              
                          *Permitted        
                          Values          
                          *               
     *Type*               `string'        
     *Default*            `\t             
                          (tab)'          


     This option specifies the string used to end each line of output.
     The default is a linefeed character (`\n').

   *  `--append'

     Options for append      *Version Introduced* 5.0.40          
     *Command-Line        `--append'        
     Format*                              


     When used with the `--tab' and `--print_data' options, this causes
     the data to be appended to any existing files having the same
     names.

*Note*:

If a table has no explicit primary key, then the output generated when
using the `--print_data' option includes the table's hidden primary key.

`--verbose=#'

Sets the level for the verbosity of the output. The minimum is 0; the
maximum is 255. The default value is 1.

Beginning with MySQL 5.0.40, it is possible to restore selected
databases, or to restore selected tables from a given database using
the syntax shown here:

     ndb_restore OTHER_OPTIONS DB_NAME,[DB_NAME[,...] | TBL_NAME[,TBL_NAME][,...]]

In other words, you can specify either of the following to be restored:

   * All tables from one or more databases

   * One or more tables from a single database

Error reporting

*Note `ndb_restore': mysql-cluster-programs-ndb-restore. reports both
temporary and permanent errors. In the case of temporary errors, it may
able to recover from them. Beginning with MySQL 5.0.29, it reports
`Restore successful, but encountered temporary error, please look at
configuration' in such cases.


File: manual.info,  Node: mysql-cluster-programs-ndb-select-all,  Next: mysql-cluster-programs-ndb-select-count,  Prev: mysql-cluster-programs-ndb-restore,  Up: mysql-cluster-programs

17.4.16 `ndb_select_all' -- Print Rows from an NDB Table
--------------------------------------------------------

*Note `ndb_select_all': mysql-cluster-programs-ndb-select-all. prints
all rows from an *Note `NDB': mysql-cluster. table to `stdout'.

*Usage*:

     ndb_select_all -c CONNECT_STRING TBL_NAME -d DB_NAME [> FILE_NAME]

*Additional Options*:

   * `--lock=LOCK_TYPE', `-l LOCK_TYPE'

     Employs a lock when reading the table. Possible values for
     LOCK_TYPE are:

        * `0': Read lock

        * `1': Read lock with hold

        * `2': Exclusive read lock

     There is no default value for this option.

   * `--order=INDEX_NAME', `-o INDEX_NAME'

     Orders the output according to the index named INDEX_NAME. Note
     that this is the name of an index, not of a column, and that the
     index must have been explicitly named when created.

   * `--descending', `-z'

     Sorts the output in descending order. This option can be used only
     in conjunction with the `-o' (`--order') option.

   * `--header=FALSE'

     Excludes column headers from the output.

   * `--useHexFormat' `-x'

     Causes all numeric values to be displayed in hexadecimal format.
     This does not affect the output of numerals contained in strings
     or datetime values.

   * `--delimiter=CHARACTER', `-D CHARACTER'

     Causes the CHARACTER to be used as a column delimiter. Only table
     data columns are separated by this delimiter.

     The default delimiter is the tab character.

   * `--rowid'

     Adds a `ROWID' column providing information about the fragments in
     which rows are stored.

   * `--gci'

     Adds a column to the output showing the global checkpoint at which
     each row was last updated. See *Note mysql-cluster-overview::, and
     *Note mysql-cluster-log-events::, for more information about
     checkpoints.

   * `--tupscan', `-t'

     Scan the table in the order of the tuples.

   * `--nodata'

     Causes any table data to be omitted.

*Sample Output*:

Output from a MySQL *Note `SELECT': select.  statement:

     mysql> SELECT * FROM ctest1.fish;
     +----+-----------+
     | id | name      |
     +----+-----------+
     |  3 | shark     |
     |  6 | puffer    |
     |  2 | tuna      |
     |  4 | manta ray |
     |  5 | grouper   |
     |  1 | guppy     |
     +----+-----------+
     6 rows in set (0.04 sec)

Output from the equivalent invocation of *Note `ndb_select_all':
mysql-cluster-programs-ndb-select-all.:

     shell> ./ndb_select_all -c localhost fish -d ctest1
     id      name
     3       [shark]
     6       [puffer]
     2       [tuna]
     4       [manta ray]
     5       [grouper]
     1       [guppy]
     6 rows returned

     NDBT_ProgramExit: 0 - OK

Note that all string values are enclosed by square brackets
(``['...`]'') in the output of *Note `ndb_select_all':
mysql-cluster-programs-ndb-select-all. For a further example, consider
the table created and populated as shown here:

     CREATE TABLE dogs (
         id INT(11) NOT NULL AUTO_INCREMENT,
         name VARCHAR(25) NOT NULL,
         breed VARCHAR(50) NOT NULL,
         PRIMARY KEY pk (id),
         KEY ix (name)
     )
     ENGINE=NDBCLUSTER;

     INSERT INTO dogs VALUES
         ('', 'Lassie', 'collie'),
         ('', 'Scooby-Doo', 'Great Dane'),
         ('', 'Rin-Tin-Tin', 'Alsatian'),
         ('', 'Rosscoe', 'Mutt');

This demonstrates the use of several additional *Note `ndb_select_all':
mysql-cluster-programs-ndb-select-all. options:

     shell> ./ndb_select_all -d ctest1 dogs -o ix -z --gci
     GCI     id name           breed
     834461  2  [Scooby-Doo]   [Great Dane]
     834878  4  [Rosscoe]      [Mutt]
     834463  3  [Rin-Tin-Tin]  [Alsatian]
     835657  1  [Lassie]       [Collie]
     4 rows returned

     NDBT_ProgramExit: 0 - OK


File: manual.info,  Node: mysql-cluster-programs-ndb-select-count,  Next: mysql-cluster-programs-ndb-show-tables,  Prev: mysql-cluster-programs-ndb-select-all,  Up: mysql-cluster-programs

17.4.17 `ndb_select_count' -- Print Row Counts for NDB Tables
-------------------------------------------------------------

*Note `ndb_select_count': mysql-cluster-programs-ndb-select-count.
prints the number of rows in one or more *Note `NDB': mysql-cluster.
tables. With a single table, the result is equivalent to that obtained
by using the MySQL statement `SELECT COUNT(*) FROM TBL_NAME'.

*Usage*:

     ndb_select_count [-c CONNECT_STRING] -dDB_NAME TBL_NAME[, TBL_NAME2[, ...]]

*Additional Options*: None that are specific to this application.
However, you can obtain row counts from multiple tables in the same
database by listing the table names separated by spaces when invoking
this command, as shown under *Sample Output*.

*Sample Output*:

     shell> ./ndb_select_count -c localhost -d ctest1 fish dogs
     6 records in table fish
     4 records in table dogs

     NDBT_ProgramExit: 0 - OK


File: manual.info,  Node: mysql-cluster-programs-ndb-show-tables,  Next: mysql-cluster-programs-ndb-size-pl,  Prev: mysql-cluster-programs-ndb-select-count,  Up: mysql-cluster-programs

17.4.18 `ndb_show_tables' -- Display List of NDB Tables
-------------------------------------------------------

*Note `ndb_show_tables': mysql-cluster-programs-ndb-show-tables.
displays a list of all *Note `NDB': mysql-cluster. database objects in
the cluster. By default, this includes not only both user-created
tables and *Note `NDB': mysql-cluster. system tables, but *Note `NDB':
mysql-cluster.-specific indexes, and internal triggers, as well.

The following table includes command options specific to the MySQL
Cluster program *Note `ndb_show_tables':
mysql-cluster-programs-ndb-show-tables.  Additional descriptions follow
the table. For options common to all MySQL Cluster programs, see *Note
mysql-cluster-program-options-common::.

*`ndb_show_tables' Command Line Options*

Format         Description                          IntroductionDeprecatedRemoved
-database=stringSpecifies the database in which the                  
               table is found                                       
-loops=#       Number of times to repeat output                     
-parsable      Return output suitable for MySQL                     
               LOAD DATA INFILE statement                           
-show-temp-statusShow table temporary flag                            
-type=#        Limit output to objects of this type                 
-unqualified   Do not qualify table names                           

*Usage*:

     ndb_show_tables [-c CONNECT_STRING]

*Additional Options*:

   *  `--database', `-d'

     Specifies the name of the database in which the tables are found.

   *  `--loops', `-l'

     Specifies the number of times the utility should execute.  This is
     1 when this option is not specified, but if you do use the option,
     you must supply an integer argument for it.

   *  `--parsable', `-p'

     Using this option causes the output to be in a format suitable for
     use with *Note `LOAD DATA INFILE': load-data.

   *  `--show-temp-status'

     If specified, this causes temporary tables to be displayed.

   *  `--type', `-t'

     Can be used to restrict the output to one type of object,
     specified by an integer type code as shown here:

        * *1*: System table

        * *2*: User-created table

        * *3*: Unique hash index

     Any other value causes all *Note `NDB': mysql-cluster. database
     objects to be listed (the default).

   *  `--unqualified', `-u'

     If specified, this causes unqualified object names to be displayed.

*Note*:

Only user-created Cluster tables may be accessed from MySQL; system
tables such as `SYSTAB_0' are not visible to *Note `mysqld': mysqld.
However, you can examine the contents of system tables using *Note
`NDB': mysql-cluster. API applications such as *Note `ndb_select_all':
mysql-cluster-programs-ndb-select-all. (see *Note
mysql-cluster-programs-ndb-select-all::).


File: manual.info,  Node: mysql-cluster-programs-ndb-size-pl,  Next: mysql-cluster-programs-ndb-waiter,  Prev: mysql-cluster-programs-ndb-show-tables,  Up: mysql-cluster-programs

17.4.19 `ndb_size.pl' -- NDBCLUSTER Size Requirement Estimator
--------------------------------------------------------------

This is a Perl script that can be used to estimate the amount of space
that would be required by a MySQL database if it were converted to use
the *Note `NDBCLUSTER': mysql-cluster.  storage engine. Unlike the
other utilities discussed in this section, it does not require access
to a MySQL Cluster (in fact, there is no reason for it to do so).
However, it does need to access the MySQL server on which the database
to be tested resides.

*Requirements*:

   * A running MySQL server. The server instance does not have to
     provide support for MySQL Cluster.

   * A working installation of Perl.

   * The `DBI' and `HTML::Template' modules, both of which can be
     obtained from CPAN if they are not already part of your Perl
     installation. (Many Linux and other operating system distributions
     provide their own packages for one or both of these libraries.)

   * The `ndb_size.tmpl' template file, which you should be able to
     find in the `share/mysql' directory of your MySQL installation.
     This file should be copied or moved into the same directory as
     `ndb_size.pl'--if it is not there already--before running the
     script.

   * A MySQL user account having the necessary privileges. If you do
     not wish to use an existing account, then creating one using
     `GRANT USAGE ON DB_NAME.*'--where DB_NAME is the name of the
     database to be examined--is sufficient for this purpose.

`ndb_size.pl' and `ndb_size.tmpl' can also be found in the MySQL
sources in `storage/ndb/tools'. If these files are not present in your
MySQL installation, you can obtain them from the MySQL Forge project
page (http://forge.mysql.com/projects/project.php?id=88).

*Usage*:

     perl ndb_size.pl DB_NAME HOSTNAME USERNAME PASSWORD > FILE_NAME.html

The command shown connects to the MySQL server at HOSTNAME using the
account of the user USERNAME having the password PASSWORD, analyzes all
of the tables in database DB_NAME, and generates a report in HTML
format which is directed to the file `FILE_NAME.html'.  (Without the
redirection, the output is sent to `stdout'.) This figure shows a
portion of the generated `ndb_size.html' output file, as viewed in a
Web browser:

Partial sample output from *Note `ndb_size.pl':
mysql-cluster-programs-ndb-size-pl. as viewed in a Web browser.

The output from this script includes:

   * Minimum values for the `DataMemory', `IndexMemory',
     `MaxNoOfTables', `MaxNoOfAttributes', `MaxNoOfOrderedIndexes',
     `MaxNoOfUniqueHashIndexes', and `MaxNoOfTriggers' configuration
     parameters required to accommodate the tables analyzed.

   * Memory requirements for all of the tables, attributes, ordered
     indexes, and unique hash indexes defined in the database.

   * The `IndexMemory' and `DataMemory' required per table and table
     row.


File: manual.info,  Node: mysql-cluster-programs-ndb-waiter,  Next: mysql-cluster-program-options-common,  Prev: mysql-cluster-programs-ndb-size-pl,  Up: mysql-cluster-programs

17.4.20 `ndb_waiter' -- Wait for MySQL Cluster to Reach a Given Status
----------------------------------------------------------------------

*Note `ndb_waiter': mysql-cluster-programs-ndb-waiter. repeatedly (each
100 milliseconds) prints out the status of all cluster data nodes until
either the cluster reaches a given status or the `--timeout' limit is
exceeded, then exits. By default, it waits for the cluster to achieve
`STARTED' status, in which all nodes have started and connected to the
cluster. This can be overridden using the `--no-contact' and
`--not-started' options (see Additional Options).

The node states reported by this utility are as follows:

   * `NO_CONTACT': The node cannot be contacted.

   * `UNKNOWN': The node can be contacted, but its status is not yet
     known. Usually, this means that the node has received a `START' or
     `RESTART' command from the management server, but has not yet
     acted on it.

   * `NOT_STARTED': The node has stopped, but remains in contact with
     the cluster. This is seen when restarting the node using the
     management client's `RESTART' command.

   * `STARTING': The node's *Note `ndbd': mysql-cluster-programs-ndbd.
     process has started, but the node has not yet joined the cluster.

   * `STARTED': The node is operational, and has joined the cluster.

   * `SHUTTING_DOWN': The node is shutting down.

   * `SINGLE USER MODE': This is shown for all cluster data nodes when
     the cluster is in single user mode.

*`ndb_waiter' Command Line Options*

Format         Description                          IntroductionDeprecatedRemoved
-no-contact    Wait for cluster to reach NO                         
               CONTACT state                                        
-not-started   Wait for cluster to reach NOT                        
               STARTED state                                        
-single-user   Wait for cluster to enter single                     
               user mode                                            
-timeout=#     Wait this many seconds, then exit                    
               whether or not cluster has  reached                  
               desired state; default is 2 minutes                  
               (120 seconds)                                        

*Usage*:

     ndb_waiter [-c CONNECT_STRING]

*Additional Options*:

   *  `--no-contact', `-n'

     Instead of waiting for the `STARTED' state, *Note `ndb_waiter':
     mysql-cluster-programs-ndb-waiter. continues running until the
     cluster reaches `NO_CONTACT' status before exiting.

   *  `--not-started'

     Instead of waiting for the `STARTED' state, *Note `ndb_waiter':
     mysql-cluster-programs-ndb-waiter. continues running until the
     cluster reaches `NOT_STARTED' status before exiting.

   *  `--timeout=SECONDS', `-t SECONDS'

     Time to wait. The program exits if the desired state is not
     achieved within this number of seconds. The default is 120 seconds
     (1200 reporting cycles).

   *  `--single-user'

     The program waits for the cluster to enter single user mode.

Sample Output

Shown here is the output from *Note `ndb_waiter':
mysql-cluster-programs-ndb-waiter.  when run against a 4-node cluster
in which two nodes have been shut down and then started again manually.
Duplicate reports (indicated by ``...'') are omitted.

     shell> ./ndb_waiter -c localhost

     Connecting to mgmsrv at (localhost)
     State node 1 STARTED
     State node 2 NO_CONTACT
     State node 3 STARTED
     State node 4 NO_CONTACT
     Waiting for cluster enter state STARTED

     ...

     State node 1 STARTED
     State node 2 UNKNOWN
     State node 3 STARTED
     State node 4 NO_CONTACT
     Waiting for cluster enter state STARTED

     ...

     State node 1 STARTED
     State node 2 STARTING
     State node 3 STARTED
     State node 4 NO_CONTACT
     Waiting for cluster enter state STARTED

     ...

     State node 1 STARTED
     State node 2 STARTING
     State node 3 STARTED
     State node 4 UNKNOWN
     Waiting for cluster enter state STARTED

     ...

     State node 1 STARTED
     State node 2 STARTING
     State node 3 STARTED
     State node 4 STARTING
     Waiting for cluster enter state STARTED

     ...

     State node 1 STARTED
     State node 2 STARTED
     State node 3 STARTED
     State node 4 STARTING
     Waiting for cluster enter state STARTED

     ...

     State node 1 STARTED
     State node 2 STARTED
     State node 3 STARTED
     State node 4 STARTED
     Waiting for cluster enter state STARTED

     NDBT_ProgramExit: 0 - OK

*Note*:

If no connectstring is specified, then *Note `ndb_waiter':
mysql-cluster-programs-ndb-waiter. tries to connect to a management on
`localhost', and reports `Connecting to mgmsrv at (null)'.


File: manual.info,  Node: mysql-cluster-program-options-common,  Prev: mysql-cluster-programs-ndb-waiter,  Up: mysql-cluster-programs

17.4.21 Options Common to MySQL Cluster Programs
------------------------------------------------

All MySQL Cluster programs (except for *Note `mysqld': mysqld.)  take
the options described in this section. Users of earlier MySQL Cluster
versions should note that some of these options have been changed to
make them consistent with one another as well as with *Note `mysqld':
mysqld. You can use the `--help' option with any MySQL Cluster program
to view a list of the options which it supports.

*Common MySQL Cluster Command line Options*

Format         Description                          IntroductionDeprecatedRemoved
-character-sets-dir=pathDirectory where character sets are                   
-core-file     Write core on errors (defaults to                    
               TRUE in debug builds)                                
-debug=options Enable output from debug calls. Can                  
               be used only for versions  compiled                  
               with debugging enabled                               
-help          Display help message and exit                        
-ndb-connectstring=connectstringSet connectstring for connecting to                  
               ndb_mgmd. Syntax:                                    
               [nodeid=<id>;][host=]<hostname>[:<port>].                
               Overrides entries specified in                       
               NDB_CONNECTSTRING or my.cnf.                         
-ndb-mgmd-host=host[:port]Set the host (and port, if desired)                  
               for connecting to the  management                    
               server                                               
-ndb-nodeid=#  Set node id for this node                            
-ndb-optimized-node-selectionSelect nodes for transactions in a                   
               more optimal way                                     
-ndb-shm       Allow for optimization using shared                  
               memory connections where  available                  
               (was EXPERIMENTAL, later REMOVED)                    
-version       Output version information and exit                  

For options specific to individual MySQL Cluster programs, see *Note
mysql-cluster-programs::.

See *Note mysql-cluster-program-options-mysqld::, for *Note `mysqld':
mysqld. options relating to MySQL Cluster.

   * `--help' `--usage', `-?'

     Options for help      *Command-Line        `--help'        
     Format*                              
     **                   `--usage'        
     **                   `-?'            


     Prints a short list with descriptions of the available command
     options.

   *  `--ndb-connectstring=CONNECT_STRING',
     `--connect-string=CONNECT_STRING', `-c CONNECT_STRING'

     Options for ndb-connectstring      *Command-Line        `--ndb-connectstring=connectstring'        
     Format*                              
     **                   `--connect-string=connectstring'        
     **                   `-c'            
                          *Permitted        
                          Values          
                          *               
     *Type*               `string'        
     *Default*            `localhost:1186'        


     This option takes a MySQL Cluster connectstring that specifies the
     management server for the application to connect to, as shown here:

          shell> ndbd --ndb-connectstring="nodeid=2;host=ndb_mgmd.mysql.com:1186"

     For more information, see *Note mysql-cluster-connectstring::.

   *  `--ndb-mgmd-host=HOST[:PORT]'

     Options for ndb-mgmd-host      *Command-Line        `--ndb-mgmd-host=host[:port]'        
     Format*                              
     *Option-File Format* `ndb-mgmd-host'        
                          *Permitted        
                          Values          
                          *               
     *Type*               `string'        
     *Default*            `localhost:1186'        


     Can be used to set the host and port number of a single management
     server for the program to connect to. If the program requires node
     IDs or references to multiple management servers (or both) in its
     connection information, use the `--ndb-connectstring' option
     instead.

   * `--character-sets-dir=NAME'

     Options for character-sets-dir      *Command-Line        `--character-sets-dir=path'        
     Format*                              
                          *Permitted        
                          Values          
                          *               
     *Type*               `file           
                          name'           
     *Default*            `'              


     Tells the program where to find character set information.

   * `--connect-string=CONNECT_STRING', `-c CONNECT_STRING'

     CONNECT_STRING sets the connectstring to the management server as
     a command option.

          shell> ndbd --connect-string="nodeid=2;host=ndb_mgmd.mysql.com:1186"

     For more information, see *Note mysql-cluster-connectstring::.

   * `--core-file'

     Options for core-file      *Command-Line        `--core-file'        
     Format*                              
                          *Permitted        
                          Values          
                          *               
     *Type*               `boolean'        
     *Default*            `FALSE'         


     Write a core file if the program dies. The name and location of
     the core file are system-dependent. (For MySQL Cluster programs
     nodes running on Linux, the default location is the program's
     working directory--for a data node, this is the node's `DataDir'.)
     For some systems, there may be restrictions or limitations; for
     example, it might be necessary to execute `ulimit -c unlimited'
     before starting the server. Consult your system documentation for
     detailed information.

     If MySQL Cluster was built using the `--debug' option for
     `configure', then `--core-file' is enabled by default. For regular
     builds, `--core-file' is disabled by default.

   * `--debug[=OPTIONS]'

     Options for debug      *Command-Line        `--debug=options'        
     Format*                              
                          *Permitted        
                          Values          
                          *               
     *Type*               `string'        
     *Default*            `d:t:O,/tmp/ndb_restore.trace'        


     This option can be used only for versions compiled with debugging
     enabled. It is used to enable output from debug calls in the same
     manner as for the *Note `mysqld': mysqld.  process.

   * `--ndb-nodeid=#'

     Options for ndb-nodeid      *Command-Line        `--ndb-nodeid=#'        
     Format*                              
                          *Permitted        
                          Values          
                          *               
     *Type*               `numeric'        
     *Default*            `0'             


     Sets this node's MySQL Cluster node ID. _The range of permitted
     values depends on the type of the node (data, management, or API)
     and the version of the MySQL Cluster software which is running on
     it_. See *Note mysql-cluster-limitations-limits::, for more
     information.

   * `--ndb-optimized-node-selection'

     Options for ndb-optimized-node-selection      *Command-Line        `--ndb-optimized-node-selection'        
     Format*                              
                          *Permitted        
                          Values          
                          *               
     *Type*               `boolean'        
     *Default*            `TRUE'          


     Optimize selection of nodes for transactions. Enabled by default.

   * `--version', `-V'

     Options for version      *Command-Line        `--version'        
     Format*                              
     **                   `-V'            


     Prints the MySQL Cluster version number of the executable. The
     version number is relevant because not all versions can be used
     together, and the MySQL Cluster startup process verifies that the
     versions of the binaries being used can co-exist in the same
     cluster. This is also important when performing an online
     (rolling) software upgrade or downgrade of MySQL Cluster. (See
     *Note mysql-cluster-rolling-restart::).

   *  `--ndb-shm'

     Options for ndb-shm      *Command-Line        `--ndb-shm'        
     Format*                              
                          *Permitted        
                          Values          
                          *               
     *Type*               `boolean'        
     *Default*            `FALSE'         


     In MySQL 5.0, this experimental option allows an application to
     use shared memory for optimization when this is available.  It is
     not intended for production use.  `--ndb-shm' is deprecated in
     MySQL 5.1, and is removed from all MySQL Cluster programs in MySQL
     Cluster NDB 7.0 and later.


File: manual.info,  Node: mysql-cluster-management,  Prev: mysql-cluster-programs,  Up: mysql-cluster

17.5 Management of MySQL Cluster
================================

* Menu:

* mysql-cluster-start-phases::   Summary of MySQL Cluster Start Phases
* mysql-cluster-mgm-client-commands::  Commands in the MySQL Cluster Management Client
* mysql-cluster-backup::         Online Backup of MySQL Cluster
* mysql-cluster-rolling-restart::  Performing a Rolling Restart of a MySQL Cluster
* mysql-cluster-event-reports::  Event Reports Generated in MySQL Cluster
* mysql-cluster-logs-ndb-messages::  MySQL Cluster Log Messages
* mysql-cluster-single-user-mode::  MySQL Cluster Single User Mode
* mysql-cluster-sql-statements::  Quick Reference: MySQL Cluster SQL Statements
* mysql-cluster-security::       MySQL Cluster Security Issues

Managing a MySQL Cluster involves a number of tasks, the first of which
is to configure and start MySQL Cluster. This is covered in *Note
mysql-cluster-configuration::, and *Note mysql-cluster-programs::.

The next few sections cover the management of a running MySQL Cluster.

For information about security issues relating to management and
deployment of a MySQL Cluster, see *Note mysql-cluster-security::.

There are essentially two methods of actively managing a running MySQL
Cluster. The first of these is through the use of commands entered into
the management client whereby cluster status can be checked, log levels
changed, backups started and stopped, and nodes stopped and started.
The second method involves studying the contents of the cluster log
`ndb_NODE_ID_cluster.log'; this is usually found in the management
server's `DataDir' directory, but this location can be overridden using
the `LogDestination' option--see *Note mysql-cluster-mgm-definition::,
for details. (Recall that NODE_ID represents the unique identifier of
the node whose activity is being logged.)  The cluster log contains
event reports generated by *Note `ndbd': mysql-cluster-programs-ndbd.
It is also possible to send cluster log entries to a Unix system log.

In addition, some aspects of the cluster's operation can be monitored
from an SQL node using the *Note `SHOW ENGINE NDB STATUS': show-engine.
statement. See *Note show-engine::, for more information.


File: manual.info,  Node: mysql-cluster-start-phases,  Next: mysql-cluster-mgm-client-commands,  Prev: mysql-cluster-management,  Up: mysql-cluster-management

17.5.1 Summary of MySQL Cluster Start Phases
--------------------------------------------

This section provides a simplified outline of the steps involved when
MySQL Cluster data nodes are started. More complete information can be
found in MySQL Cluster Start Phases
(http://dev.mysql.com/doc/ndbapi/en/ndb-internals-start-phases.html).

These phases are the same as those reported in the output from the
`NODE_ID STATUS' command in the management client. (See *Note
mysql-cluster-mgm-client-commands::, for more information about this
command.)

Start types

There are several different startup types and modes, as shown here:

   * Initial Start

     The cluster starts with a clean file system on all data nodes.
     This occurs either when the cluster started for the very first
     time, or when all data nodes are restarted using the `--initial'
     option.

     *Note*:

     Disk Data files are not removed when restarting a node using
     `--initial'.

   * System Restart

     The cluster starts and reads data stored in the data nodes.  This
     occurs when the cluster has been shut down after having been in
     use, when it is desired for the cluster to resume operations from
     the point where it left off.

   * Node Restart

     This is the online restart of a cluster node while the cluster
     itself is running.

   * Initial Node Restart

     This is the same as a node restart, except that the node is
     reinitialized and started with a clean file system.

Setup and initialization (Phase -1)

Prior to startup, each data node (*Note `ndbd':
mysql-cluster-programs-ndbd.  process) must be initialized.
Initialization consists of the following steps:

  1. Obtain a node ID

  2. Fetch configuration data

  3. Allocate ports to be used for inter-node communications

  4. Allocate memory according to settings obtained from the
     configuration file

When a data node or SQL node first connects to the management node, it
reserves a cluster node ID. To make sure that no other node allocates
the same node ID, this ID is retained until the node has managed to
connect to the cluster and at least one *Note `ndbd':
mysql-cluster-programs-ndbd. reports that this node is connected. This
retention of the node ID is guarded by the connection between the node
in question and *Note `ndb_mgmd': mysql-cluster-programs-ndb-mgmd.

Normally, in the event of a problem with the node, the node disconnects
from the management server, the socket used for the connection is
closed, and the reserved node ID is freed. However, if a node is
disconnected abruptly--for example, due to a hardware failure in one of
the cluster hosts, or because of network issues--the normal closing of
the socket by the operating system may not take place. In this case,
the node ID continues to be reserved and not released until a TCP
timeout occurs 10 or so minutes later.

To take care of this problem, you can use `PURGE STALE SESSIONS'.
Running this statement forces all reserved node IDs to be checked; any
that are not being used by nodes actually connected to the cluster are
then freed.

Beginning with MySQL 5.1.11, timeout handling of node ID assignments is
implemented. This performs the ID usage checks automatically after
approximately 20 seconds, so that `PURGE STALE SESSIONS' should no
longer be necessary in a normal Cluster start.

After each data node has been initialized, the cluster startup process
can proceed. The stages which the cluster goes through during this
process are listed here:

   * Phase 0

     The `NDBFS' and `NDBCNTR' blocks start (see `NDB' Kernel Blocks
     (http://dev.mysql.com/doc/ndbapi/en/ndb-internals-kernel-blocks.html)).
     The cluster file system is cleared, if the cluster was started
     with the `--initial' option.

   * Phase 1

     In this stage, all remaining *Note `NDB': mysql-cluster. kernel
     blocks are started.  Cluster connections are set up, inter-block
     communications are established, and Cluster heartbeats are
     started. In the case of a node restart, API node connections are
     also checked.

     *Note*:

     When one or more nodes hang in Phase 1 while the remaining node or
     nodes hang in Phase 2, this often indicates network problems. One
     possible cause of such issues is one or more cluster hosts having
     multiple network interfaces. Another common source of problems
     causing this condition is the blocking of TCP/IP ports needed for
     communications between cluster nodes. In the latter case, this is
     often due to a misconfigured firewall.

   * Phase 2

     The `NDBCNTR' kernel block checks the states of all existing
     nodes. The master node is chosen, and the cluster schema file is
     initialized.

   * Phase 3

     The `DBLQH' and `DBTC' kernel blocks set up communications between
     them. The startup type is determined; if this is a restart, the
     `DBDIH' block obtains permission to perform the restart.

   * Phase 4

     For an initial start or initial node restart, the redo log files
     are created. The number of these files is equal to
     `NoOfFragmentLogFiles'.

     For a system restart:

        * Read schema or schemas.

        * Read data from the local checkpoint.

        * Apply all redo information until the latest restorable global
          checkpoint has been reached.

     For a node restart, find the tail of the redo log.

   * Phase 5

     Most of the database-related portion of a data node start is
     performed during this phase. For an initial start or system
     restart, a local checkpoint is executed, followed by a global
     checkpoint. Periodic checks of memory usage begin during this
     phase, and any required node takeovers are performed.

   * Phase 6

     In this phase, node groups are defined and set up.

   * Phase 7

     The arbitrator node is selected and begins to function. The next
     backup ID is set, as is the backup disk write speed.  Nodes
     reaching this start phase are marked as `Started'. It is now
     possible for API nodes (including SQL nodes) to connect to the
     cluster. connect.

   * Phase 8

     If this is a system restart, all indexes are rebuilt (by `DBDIH').

   * Phase 9

     The node internal startup variables are reset.

   * Phase 100 (_OBSOLETE_)

     Formerly, it was at this point during a node restart or initial
     node restart that API nodes could connect to the node and begin to
     receive events. Currently, this phase is empty.

   * Phase 101

     At this point in a node restart or initial node restart, event
     delivery is handed over to the node joining the cluster. The newly
     joined node takes over responsibility for delivering its primary
     data to subscribers. This phase is also referred to as _`SUMA'
     handover phase_.

After this process is completed for an initial start or system restart,
transaction handling is enabled. For a node restart or initial node
restart, completion of the startup process means that the node may now
act as a transaction coordinator.


File: manual.info,  Node: mysql-cluster-mgm-client-commands,  Next: mysql-cluster-backup,  Prev: mysql-cluster-start-phases,  Up: mysql-cluster-management

17.5.2 Commands in the MySQL Cluster Management Client
------------------------------------------------------

In addition to the central configuration file, a cluster may also be
controlled through a command-line interface available through the
management client *Note `ndb_mgm': mysql-cluster-programs-ndb-mgm. This
is the primary administrative interface to a running cluster.

Commands for the event logs are given in *Note
mysql-cluster-event-reports::; commands for creating backups and
restoring from them are provided in *Note mysql-cluster-backup::.

The management client has the following basic commands. In the listing
that follows, NODE_ID denotes either a database node ID or the keyword
`ALL', which indicates that the command should be applied to all of the
cluster's data nodes.

   * `HELP'

     Displays information on all available commands.

   * `SHOW'

     Displays information on the cluster's status.

     *Note*:

     In a cluster where multiple management nodes are in use, this
     command displays information only for data nodes that are actually
     connected to the current management server.

   * `NODE_ID START'

     Brings online the data node identified by NODE_ID (or all data
     nodes).

     Beginning with MySQL 5.0.19, this command can also be used to
     individual management nodes online.

     *Note*:

     `ALL START' continues to affect data nodes only.

     *Important*:

     To use this command to bring a data node online, the data node
     must have been started using *Note `ndbd --nostart':
     mysql-cluster-programs-ndbd. or *Note `ndbd -n':
     mysql-cluster-programs-ndbd.

   * `NODE_ID STOP'

     Stops the data node identified by NODE_ID (or all data nodes).

     Beginning with MySQL 5.0.19, this command can also be used to stop
     individual management nodes.

     *Note*:

     `ALL STOP' continues to affect data nodes only.

     A node affected by this command disconnects from the cluster, and
     its associated *Note `ndbd': mysql-cluster-programs-ndbd. or *Note
     `ndb_mgmd': mysql-cluster-programs-ndb-mgmd. process terminates.

   * `NODE_ID RESTART [-n] [-i]'

     Restarts the data node identified by NODE_ID (or all data nodes).

     Using the `-i' option with `RESTART' causes the data node to
     perform an initial restart; that is, the node's file system is
     deleted and recreated. The effect is the same as that obtained from
     stopping the data node process and then starting it again using
     *Note `ndbd --initial': mysql-cluster-programs-ndbd. from the
     system shell.

     Using the `-n' option causes the data node process to be
     restarted, but the data node is not actually brought online until
     the appropriate `START' command is issued. The effect of this
     option is the same as that obtained from stopping the data node
     and then starting it again using `ndbd --nostart' or `ndbd -n'
     from the system shell.

   * `NODE_ID STATUS'

     Displays status information for the data node identified by
     NODE_ID (or for all data nodes).

   * `ENTER SINGLE USER MODE NODE_ID'

     Enters single user mode, whereby only the MySQL server identified
     by the node ID NODE_ID is permitted to access the database.

     *Important*:

     Do not attempt to have data nodes join the cluster while it is
     running in single user mode. Doing so can cause subsequent
     multiple node failures. Beginning with MySQL 5.0.29, it is no
     longer possible to add nodes while in single user mode. (See Bug
     #20395 for more information.)

   * `EXIT SINGLE USER MODE'

     Exits single user mode, enabling all SQL nodes (that is, all
     running *Note `mysqld': mysqld. processes) to access the database.

     *Note*:

     It is possible to use `EXIT SINGLE USER MODE' even when not in
     single user mode, although the command has no effect in this case.

   * `QUIT', `EXIT'

     Terminates the management client.

     This command does not affect any nodes connected to the cluster.

   * `SHUTDOWN'

     Shuts down all cluster data nodes and management nodes. To exit
     the management client after this has been done, use `EXIT' or
     `QUIT'.

     This command does _not_ shut down any SQL nodes or API nodes that
     are connected to the cluster.


File: manual.info,  Node: mysql-cluster-backup,  Next: mysql-cluster-rolling-restart,  Prev: mysql-cluster-mgm-client-commands,  Up: mysql-cluster-management

17.5.3 Online Backup of MySQL Cluster
-------------------------------------

* Menu:

* mysql-cluster-backup-concepts::  MySQL Cluster Backup Concepts
* mysql-cluster-backup-using-management-client::  Using The MySQL Cluster Management Client to Create a Backup
* mysql-cluster-backup-configuration::  Configuration for MySQL Cluster Backups
* mysql-cluster-backup-troubleshooting::  MySQL Cluster Backup Troubleshooting

The next few sections describe how to prepare for and then to create a
MySQL Cluster backup using the functionality for this purpose found in
the *Note `ndb_mgm': mysql-cluster-programs-ndb-mgm. management client.
To distinguish this type of backup from a backup made using *Note
`mysqldump': mysqldump, we sometimes refer to it as a `native' MySQL
Cluster backup. (For information about the creation of backups with
*Note `mysqldump': mysqldump, see *Note mysqldump::.) Restoration of
MySQL Cluster backups is done using the *Note `ndb_restore':
mysql-cluster-programs-ndb-restore. utility provided with the MySQL
Cluster distribution; for information about *Note `ndb_restore':
mysql-cluster-programs-ndb-restore. and its use in restoring MySQL
Cluster backups, see *Note mysql-cluster-programs-ndb-restore::.


File: manual.info,  Node: mysql-cluster-backup-concepts,  Next: mysql-cluster-backup-using-management-client,  Prev: mysql-cluster-backup,  Up: mysql-cluster-backup

17.5.3.1 MySQL Cluster Backup Concepts
......................................

A backup is a snapshot of the database at a given time. The backup
consists of three main parts:

   * Metadata

     The names and definitions of all database tables

   * Table records

     The data actually stored in the database tables at the time that
     the backup was made

   * Transaction log

     A sequential record telling how and when data was stored in the
     database

Each of these parts is saved on all nodes participating in the backup.
During backup, each node saves these three parts into three files on
disk:

   * `BACKUP-BACKUP_ID.NODE_ID.ctl'

     A control file containing control information and metadata.  Each
     node saves the same table definitions (for all tables in the
     cluster) to its own version of this file.

   * `BACKUP-BACKUP_ID-0.NODE_ID.data'

     A data file containing the table records, which are saved on a
     per-fragment basis. That is, different nodes save different
     fragments during the backup. The file saved by each node starts
     with a header that states the tables to which the records belong.
     Following the list of records there is a footer containing a
     checksum for all records.

   * `BACKUP-BACKUP_ID.NODE_ID.log'

     A log file containing records of committed transactions.  Only
     transactions on tables stored in the backup are stored in the log.
     Nodes involved in the backup save different records because
     different nodes host different database fragments.

In the listing above, BACKUP_ID stands for the backup identifier and
NODE_ID is the unique identifier for the node creating the file.


File: manual.info,  Node: mysql-cluster-backup-using-management-client,  Next: mysql-cluster-backup-configuration,  Prev: mysql-cluster-backup-concepts,  Up: mysql-cluster-backup

17.5.3.2 Using The MySQL Cluster Management Client to Create a Backup
.....................................................................

Before starting a backup, make sure that the cluster is properly
configured for performing one. (See *Note
mysql-cluster-backup-configuration::.)

The `START BACKUP' command is used to create a backup:

     START BACKUP [BACKUP_ID] [WAIT_OPTION]

     WAIT_OPTION:
     WAIT {STARTED | COMPLETED} | NOWAIT

Successive backups are automatically identified sequentially, so the
BACKUP_ID, an integer greater than or equal to 1, is optional; if it is
omitted, the next available value is used. If an existing BACKUP_ID
value is used, the backup fails with the error `Backup failed: file
already exists'. If used, the BACKUP_ID must follow `START BACKUP'
immediately, before any other options are used.

The maximum supported value for BACKUP_ID in MySQL 5.0 is 2147483648
(2^31). (Bug #43042)

*Note*:

If you start a backup using *Note `ndb_mgm -e "START BACKUP"':
mysql-cluster-programs-ndb-mgm, the BACKUP_ID is required.

The WAIT_OPTION can be used to determine when control is returned to
the management client after a `START BACKUP' command is issued, as
shown in the following list:

   * If `NOWAIT' is specified, the management client displays a prompt
     immediately, as seen here:

          ndb_mgm> START BACKUP NOWAIT
          ndb_mgm>

     In this case, the management client can be used even while it
     prints progress information from the backup process.

   * With `WAIT STARTED' the management client waits until the backup
     has started before returning control to the user, as shown here:

          ndb_mgm> START BACKUP WAIT STARTED
          Waiting for started, this may take several minutes
          Node 2: Backup 3 started from node 1
          ndb_mgm>

   * WAIT COMPLETED causes the management client to wait until the
     backup process is complete before returning control to the user.

`WAIT COMPLETED' is the default.

The procedure for creating a backup consists of the following steps:

  1. Start the management client (*Note `ndb_mgm':
     mysql-cluster-programs-ndb-mgm.), if it not running already.

  2. Execute the START BACKUP command.  This produces several lines of
     output indicating the progress of the backup, as shown here:

          ndb_mgm> START BACKUP
          Waiting for completed, this may take several minutes
          Node 2: Backup 1 started from node 1
          Node 2: Backup 1 started from node 1 completed
           StartGCP: 177 StopGCP: 180
           #Records: 7362 #LogRecords: 0
           Data: 453648 bytes Log: 0 bytes
          ndb_mgm>

  3. When the backup has started the management client displays this
     message:

          Backup BACKUP_ID started from node NODE_ID

     BACKUP_ID is the unique identifier for this particular backup.
     This identifier is saved in the cluster log, if it has not been
     configured otherwise. NODE_ID is the identifier of the management
     server that is coordinating the backup with the data nodes. At
     this point in the backup process the cluster has received and
     processed the backup request. It does not mean that the backup has
     finished. An example of this statement is shown here:


          Node 2: Backup 1 started from node 1

  4. The management client indicates with a message like this one that
     the backup has started:

          Backup BACKUP_ID started from node NODE_ID completed

     As is the case for the notification that the backup has started,
     BACKUP_ID is the unique identifier for this particular backup, and
     NODE_ID is the node ID of the management server that is
     coordinating the backup with the data nodes. This output is
     accompanied by additional information including relevant global
     checkpoints, the number of records backed up, and the size of the
     data, as shown here:


          Node 2: Backup 1 started from node 1 completed
           StartGCP: 177 StopGCP: 180
           #Records: 7362 #LogRecords: 0
           Data: 453648 bytes Log: 0 bytes

It is also possible to perform a backup from the system shell by
invoking *Note `ndb_mgm': mysql-cluster-programs-ndb-mgm. with the `-e'
or `--execute' option, as shown in this example:

     shell> ndb_mgm -e "START BACKUP 6 WAIT COMPLETED"

When using `START BACKUP' in this way, you must specify the backup ID.

Cluster backups are created by default in the `BACKUP' subdirectory of
the `DataDir' on each data node. This can be overridden for one or more
data nodes individually, or for all cluster data nodes in the
`config.ini' file using the `BackupDataDir' configuration parameter as
discussed in Identifying Data Nodes. The backup files created for a
backup with a given BACKUP_ID are stored in a subdirectory named
`BACKUP-BACKUP_ID' in the backup directory.

To abort a backup that is already in progress:

  1. Start the management client.

  2. Execute this command:

          ndb_mgm> ABORT BACKUP BACKUP_ID

     The number BACKUP_ID is the identifier of the backup that was
     included in the response of the management client when the backup
     was started (in the message `Backup BACKUP_ID started from node
     MANAGEMENT_NODE_ID').

  3. The management client will acknowledge the abort request with
     `Abort of backup BACKUP_ID ordered'.

     *Note*:

     At this point, the management client has not yet received a
     response from the cluster data nodes to this request, and the
     backup has not yet actually been aborted.

  4. After the backup has been aborted, the management client will
     report this fact in a manner similar to what is shown here:

          Node 1: Backup 3 started from 5 has been aborted. Error: 1321 - Backup aborted by user request: Permanent error: User defined error
          Node 3: Backup 3 started from 5 has been aborted. Error: 1323 - 1323: Permanent error: Internal error
          Node 2: Backup 3 started from 5 has been aborted. Error: 1323 - 1323: Permanent error: Internal error
          Node 4: Backup 3 started from 5 has been aborted. Error: 1323 - 1323: Permanent error: Internal error

     In this example, we have shown sample output for a cluster with 4
     data nodes, where the sequence number of the backup to be aborted
     is `3', and the management node to which the cluster management
     client is connected has the node ID `5'. The first node to complete
     its part in aborting the backup reports that the reason for the
     abort was due to a request by the user. (The remaining nodes
     report that the backup was aborted due to an unspecified internal
     error.)

     *Note*:

     There is no guarantee that the cluster nodes respond to an `ABORT
     BACKUP' command in any particular order.

     The `Backup BACKUP_ID started from node MANAGEMENT_NODE_ID has been
     aborted' messages mean that the backup has been terminated and
     that all files relating to this backup have been removed from the
     cluster file system.

It is also possible to abort a backup in progress from a system shell
using this command:

     shell> ndb_mgm -e "ABORT BACKUP BACKUP_ID"

*Note*:

If there is no backup having the ID BACKUP_ID running when an `ABORT
BACKUP' is issued, the management client makes no response, nor is it
indicated in the cluster log that an invalid abort command was sent.


File: manual.info,  Node: mysql-cluster-backup-configuration,  Next: mysql-cluster-backup-troubleshooting,  Prev: mysql-cluster-backup-using-management-client,  Up: mysql-cluster-backup

17.5.3.3 Configuration for MySQL Cluster Backups
................................................

Five configuration parameters are essential for backup:

   * `BackupDataBufferSize'

     The amount of memory used to buffer data before it is written to
     disk.

   * `BackupLogBufferSize'

     The amount of memory used to buffer log records before these are
     written to disk.

   * `BackupMemory'

     The total memory allocated in a database node for backups.  This
     should be the sum of the memory allocated for the backup data
     buffer and the backup log buffer.

   * `BackupWriteSize'

     The default size of blocks written to disk. This applies for both
     the backup data buffer and the backup log buffer.

   * `BackupMaxWriteSize'

     The maximum size of blocks written to disk. This applies for both
     the backup data buffer and the backup log buffer.

More detailed information about these parameters can be found in Backup
Parameters.


File: manual.info,  Node: mysql-cluster-backup-troubleshooting,  Prev: mysql-cluster-backup-configuration,  Up: mysql-cluster-backup

17.5.3.4 MySQL Cluster Backup Troubleshooting
.............................................

If an error code is returned when issuing a backup request, the most
likely cause is insufficient memory or disk space. You should check
that there is enough memory allocated for the backup.

*Important*:

If you have set `BackupDataBufferSize' and `BackupLogBufferSize' and
their sum is greater than 4MB, then you must also set `BackupMemory' as
well. See `BackupMemory'.

You should also make sure that there is sufficient space on the hard
drive partition of the backup target.

*Note `NDB': mysql-cluster. does not support repeatable reads, which
can cause problems with the restoration process.  Although the backup
process is `hot', restoring a MySQL Cluster from backup is not a 100%
`hot' process. This is due to the fact that, for the duration of the
restore process, running transactions get nonrepeatable reads from the
restored data. This means that the state of the data is inconsistent
while the restore is in progress.


File: manual.info,  Node: mysql-cluster-rolling-restart,  Next: mysql-cluster-event-reports,  Prev: mysql-cluster-backup,  Up: mysql-cluster-management

17.5.4 Performing a Rolling Restart of a MySQL Cluster
------------------------------------------------------

This section discusses how to perform a _rolling restart_ of a MySQL
Cluster installation, so called because it involves stopping and
starting (or restarting) each node in turn, so that the cluster itself
remains operational. This is often done as part of a _rolling upgrade_
or _rolling downgrade_, where high availability of the cluster is
mandatory and no downtime of the cluster as a whole is permissible.
Where we refer to upgrades, the information provided here also
generally applies to downgrades as well.

There are a number of reasons why a rolling restart might be desirable.
These are described in the next few paragraphs.

Configuration change

To make a change in the cluster's configuration, such as adding an SQL
node to the cluster, or setting a configuration parameter to a new
value.

MySQL Cluster software upgrade or downgrade

To upgrade the cluster to a newer version of the MySQL Cluster software
(or to downgrade it to an older version). This is usually referred to
as a `rolling upgrade' (or `rolling downgrade', when reverting to an
older version of MySQL Cluster).

Change on node host

To make changes in the hardware or operating system on which one or
more MySQL Cluster node processes are running.

System reset (cluster reset)

To reset the cluster because it has reached an undesirable state. In
such cases it is often desirable to reload the data and metadata of one
or more data nodes. This can be done any of three ways:

   * Start each data node process (*Note `ndbd':
     mysql-cluster-programs-ndbd.) with the `--initial' option, which
     forces the data node to clear its file system and to reload all
     MySQL Cluster data and metadata from the other data nodes.

   * Create a backup using the *Note `ndb_mgm':
     mysql-cluster-programs-ndb-mgm. client `BACKUP' command prior to
     performing the restart. Following the upgrade, restore the node or
     nodes using *Note `ndb_restore':
     mysql-cluster-programs-ndb-restore.

     See *Note mysql-cluster-backup::, and *Note
     mysql-cluster-programs-ndb-restore::, for more information.

   * Use *Note `mysqldump': mysqldump. to create a backup prior to the
     upgrade; afterward, restore the dump using *Note `LOAD DATA
     INFILE': load-data.

Resource Recovery

To free memory previously allocated to a table by successive *Note
`INSERT': insert. and *Note `DELETE': delete. operations, for re-use by
other MySQL Cluster tables.

The process for performing a rolling restart may be generalized as
follows:

  1. Stop all cluster management nodes (*Note `ndb_mgmd':
     mysql-cluster-programs-ndb-mgmd.  processes), reconfigure them,
     then restart them.

  2. Stop, reconfigure, then restart each cluster data node (*Note
     `ndbd': mysql-cluster-programs-ndbd. process) in turn.

  3. Stop, reconfigure, then restart each cluster SQL node (*Note
     `mysqld': mysqld. process) in turn.

The specifics for implementing a given rolling upgrade depend upon the
changes being made. A more detailed view of the process is presented
here:

MySQL Cluster Rolling Restarts (By Type)

In the previous diagram, the *Stop* and *Start* steps indicate that the
process must be stopped completely using a shell command (such as *Note
`kill': kill. on most Unix systems) or the management client `STOP'
command, then started again from a system shell by invoking the *Note
`ndbd': mysql-cluster-programs-ndbd. or *Note `ndb_mgmd':
mysql-cluster-programs-ndb-mgmd. executable as appropriate.

*Restart* indicates that the process may be restarted using the *Note
`ndb_mgm': mysql-cluster-programs-ndb-mgm.  management client `RESTART'
command (see *Note mysql-cluster-mgm-client-commands::).

*Important*:

When performing an upgrade or downgrade of the MySQL Cluster software,
you must upgrade or downgrade the management nodes first, then the data
nodes, and finally the SQL nodes. Doing so in any other order may leave
the cluster in an unusable state.


File: manual.info,  Node: mysql-cluster-event-reports,  Next: mysql-cluster-logs-ndb-messages,  Prev: mysql-cluster-rolling-restart,  Up: mysql-cluster-management

17.5.5 Event Reports Generated in MySQL Cluster
-----------------------------------------------

* Menu:

* mysql-cluster-logging-management-commands::  MySQL Cluster Logging Management Commands
* mysql-cluster-log-events::     MySQL Cluster Log Events
* mysql-cluster-log-statistics::  Using `CLUSTERLOG STATISTICS' in the MySQL Cluster Management Client

In this section, we discuss the types of event logs provided by MySQL
Cluster, and the types of events that are logged.

MySQL Cluster provides two types of event log:

   * The _cluster log_, which includes events generated by all cluster
     nodes. The cluster log is the log recommended for most uses
     because it provides logging information for an entire cluster in a
     single location.

     By default, the cluster log is saved to a file named
     `ndb_NODE_ID_cluster.log', (where NODE_ID is the node ID of the
     management server) in the same directory where the *Note
     `ndb_mgm': mysql-cluster-programs-ndb-mgm. binary resides.

     Cluster logging information can also be sent to `stdout' or a
     `syslog' facility in addition to or instead of being saved to a
     file, as determined by the values set for the `DataDir' and
     `LogDestination' configuration parameters.  See *Note
     mysql-cluster-mgm-definition::, for more information about these
     parameters.

   * _Node logs_ are local to each node.

     Output generated by node event logging is written to the file
     `ndb_NODE_ID_out.log' (where NODE_ID is the node's node ID) in the
     node's `DataDir'. Node event logs are generated for both
     management nodes and data nodes.

     Node logs are intended to be used only during application
     development, or for debugging application code.

Both types of event logs can be set to log different subsets of events.

Each reportable event can be distinguished according to three different
criteria:

   * _Category_: This can be any one of the following values: `STARTUP',
     `SHUTDOWN', `STATISTICS', `CHECKPOINT', `NODERESTART',
     `CONNECTION', `ERROR', or `INFO'.

   * _Priority_: This is represented by one of the numbers from 1 to 15
     inclusive, where 1 indicates `most important' and 15 `least
     important.'

   * _Severity Level_: This can be any one of the following values:
     `ALERT', `CRITICAL', `ERROR', `WARNING', `INFO', or `DEBUG'.

Both the cluster log and the node log can be filtered on these
properties.

The format used in the cluster log is as shown here:

     2007-01-26 19:35:55 [MgmSrvr] INFO     -- Node 1: Data usage is 2%(60 32K pages of total 2560)
     2007-01-26 19:35:55 [MgmSrvr] INFO     -- Node 1: Index usage is 1%(24 8K pages of total 2336)
     2007-01-26 19:35:55 [MgmSrvr] INFO     -- Node 1: Resource 0 min: 0 max: 639 curr: 0
     2007-01-26 19:35:55 [MgmSrvr] INFO     -- Node 2: Data usage is 2%(76 32K pages of total 2560)
     2007-01-26 19:35:55 [MgmSrvr] INFO     -- Node 2: Index usage is 1%(24 8K pages of total 2336)
     2007-01-26 19:35:55 [MgmSrvr] INFO     -- Node 2: Resource 0 min: 0 max: 639 curr: 0
     2007-01-26 19:35:55 [MgmSrvr] INFO     -- Node 3: Data usage is 2%(58 32K pages of total 2560)
     2007-01-26 19:35:55 [MgmSrvr] INFO     -- Node 3: Index usage is 1%(25 8K pages of total 2336)
     2007-01-26 19:35:55 [MgmSrvr] INFO     -- Node 3: Resource 0 min: 0 max: 639 curr: 0
     2007-01-26 19:35:55 [MgmSrvr] INFO     -- Node 4: Data usage is 2%(74 32K pages of total 2560)
     2007-01-26 19:35:55 [MgmSrvr] INFO     -- Node 4: Index usage is 1%(25 8K pages of total 2336)
     2007-01-26 19:35:55 [MgmSrvr] INFO     -- Node 4: Resource 0 min: 0 max: 639 curr: 0
     2007-01-26 19:39:42 [MgmSrvr] INFO     -- Node 4: Node 9 Connected
     2007-01-26 19:39:42 [MgmSrvr] INFO     -- Node 1: Node 9 Connected
     2007-01-26 19:39:42 [MgmSrvr] INFO     -- Node 1: Node 9: API version 5.1.15
     2007-01-26 19:39:42 [MgmSrvr] INFO     -- Node 2: Node 9 Connected
     2007-01-26 19:39:42 [MgmSrvr] INFO     -- Node 2: Node 9: API version 5.1.15
     2007-01-26 19:39:42 [MgmSrvr] INFO     -- Node 3: Node 9 Connected
     2007-01-26 19:39:42 [MgmSrvr] INFO     -- Node 3: Node 9: API version 5.1.15
     2007-01-26 19:39:42 [MgmSrvr] INFO     -- Node 4: Node 9: API version 5.1.15
     2007-01-26 19:59:22 [MgmSrvr] ALERT    -- Node 2: Node 7 Disconnected
     2007-01-26 19:59:22 [MgmSrvr] ALERT    -- Node 2: Node 7 Disconnected

Each line in the cluster log contains the following information:

   * A timestamp in `YYYY-MM-DD HH:MM:SS' format.

   * The type of node which is performing the logging. In the cluster
     log, this is always `[MgmSrvr]'.

   * The severity of the event.

   * The ID of the node reporting the event.

   * A description of the event. The most common types of events to
     appear in the log are connections and disconnections between
     different nodes in the cluster, and when checkpoints occur. In
     some cases, the description may contain status information.


File: manual.info,  Node: mysql-cluster-logging-management-commands,  Next: mysql-cluster-log-events,  Prev: mysql-cluster-event-reports,  Up: mysql-cluster-event-reports

17.5.5.1 MySQL Cluster Logging Management Commands
..................................................

The following management commands are related to the cluster log:

   * `CLUSTERLOG ON'

     Turns the cluster log on.

   * `CLUSTERLOG OFF'

     Turns the cluster log off.

   * `CLUSTERLOG INFO'

     Provides information about cluster log settings.

   * `NODE_ID CLUSTERLOG CATEGORY=THRESHOLD'

     Logs CATEGORY events with priority less than or equal to THRESHOLD
     in the cluster log.

   * `CLUSTERLOG FILTER SEVERITY_LEVEL'

     Toggles cluster logging of events of the specified SEVERITY_LEVEL.

The following table describes the default setting (for all data nodes)
of the cluster log category threshold. If an event has a priority with
a value lower than or equal to the priority threshold, it is reported
in the cluster log.

Note that events are reported per data node, and that the threshold can
be set to different values on different nodes.

Category               Default threshold (All data nodes)
`STARTUP'              *7*
`SHUTDOWN'             *7*
`STATISTICS'           *7*
`CHECKPOINT'           *7*
`NODERESTART'          *7*
`CONNECTION'           *7*
`ERROR'                *15*
`INFO'                 *7*

The `STATISTICS' category can provide a great deal of useful data. See
*Note mysql-cluster-log-statistics::, for more information.

Thresholds are used to filter events within each category. For example,
a `STARTUP' event with a priority of 3 is not logged unless the
threshold for `STARTUP' is set to 3 or higher. Only events with
priority 3 or lower are sent if the threshold is 3.

The following table shows the event severity levels.

*Note*:

These correspond to Unix `syslog' levels, except for `LOG_EMERG' and
`LOG_NOTICE', which are not used or mapped.

*1*     `ALERT'        A condition that should be corrected immediately,
                       such as a corrupted system database
*2*     `CRITICAL'     Critical conditions, such as device errors or
                       insufficient resources
*3*     `ERROR'        Conditions that should be corrected, such as
                       configuration errors
*4*     `WARNING'      Conditions that are not errors, but that might
                       require special handling
*5*     `INFO'         Informational messages
*6*     `DEBUG'        Debugging messages used for *Note `NDBCLUSTER':
                       mysql-cluster.  development

Event severity levels can be turned on or off (using `CLUSTERLOG
FILTER'--see above). If a severity level is turned on, then all events
with a priority less than or equal to the category thresholds are
logged. If the severity level is turned off then no events belonging to
that severity level are logged.

*Important*:

Cluster log levels are set on a per *Note `ndb_mgmd':
mysql-cluster-programs-ndb-mgmd, per subscriber basis. This means that,
in a MySQL Cluster with multiple management servers, using a
`CLUSTERLOG' command in an instance of *Note `ndb_mgm':
mysql-cluster-programs-ndb-mgm. connected to one management server
affects only logs generated by that management server but not by any of
the others. This also means that, should one of the management servers
be restarted, only logs generated by that management server are
affected by the resetting of log levels caused by the restart.


File: manual.info,  Node: mysql-cluster-log-events,  Next: mysql-cluster-log-statistics,  Prev: mysql-cluster-logging-management-commands,  Up: mysql-cluster-event-reports

17.5.5.2 MySQL Cluster Log Events
.................................

An event report reported in the event logs has the following format:

     DATETIME [STRING] SEVERITY -- MESSAGE

For example:

     09:19:30 2005-07-24 [NDB] INFO -- Node 4 Start phase 4 completed

This section discusses all reportable events, ordered by category and
severity level within each category.

In the event descriptions, GCP and LCP mean `Global Checkpoint' and
`Local Checkpoint', respectively.

*`CONNECTION' Events*

These events are associated with connections between Cluster nodes.

Event                     PrioritySeverityDescription
                                  Level   
data nodes connected      8       `INFO'  Data nodes connected
data nodes disconnected   8       `INFO'  Data nodes disconnected
Communication closed      8       `INFO'  SQL node or data node
                                          connection closed
Communication opened      8       `INFO'  SQL node or data node
                                          connection opened

*`CHECKPOINT' Events*

The logging messages shown here are associated with checkpoints.

Event                     PrioritySeverityDescription
                                  Level   
LCP stopped in calc keep  0       `ALERT' LCP stopped
GCI                                       
Local checkpoint          11      `INFO'  LCP on a fragment has been
fragment completed                        completed
Global checkpoint         10      `INFO'  GCP finished
completed                                 
Global checkpoint started 9       `INFO'  Start of GCP: REDO log is
                                          written to disk
Local checkpoint          8       `INFO'  LCP completed normally
completed                                 
Local checkpoint started  7       `INFO'  Start of LCP: data written to
                                          disk
Report undo log blocked   7       `INFO'  UNDO logging blocked; buffer
                                          near overflow

*`STARTUP' Events*

The following events are generated in response to the startup of a node
or of the cluster and of its success or failure. They also provide
information relating to the progress of the startup process, including
information concerning logging activities.

Event                     PrioritySeverityDescription
                                  Level   
Internal start signal     15      `INFO'  Blocks received after
received STTORRY                          completion of restart
Undo records executed     15      `INFO'  
New REDO log started      10      `INFO'  GCI keep X, newest restorable
                                          GCI Y
New log started           10      `INFO'  Log part X, start MB Y, stop MB
                                          Z
Node has been refused     8       `INFO'  Node cannot be included in
for inclusion in the                      cluster due to
cluster                                   misconfiguration, inability to
                                          establish communication, or
                                          other problem
data node neighbors       8       `INFO'  Shows neighboring data nodes
data node start phase X   4       `INFO'  A data node start phase has
completed                                 been completed
Node has been             3       `INFO'  Displays the node, managing
successfully included                     node, and dynamic ID
into the cluster                          
data node start phases    1       `INFO'  NDB Cluster nodes starting
initiated                                 
data node all start       1       `INFO'  NDB Cluster nodes started
phases completed                          
data node shutdown        1       `INFO'  Shutdown of data node has
initiated                                 commenced
data node shutdown        1       `INFO'  Unable to shut down data node
aborted                                   normally

*`NODERESTART' Events*

The following events are generated when restarting a node and relate to
the success or failure of the node restart process.

Event                     PrioritySeverityDescription
                                  Level   
Node failure phase        8       `ALERT' Reports completion of node
completed                                 failure phases
Node has failed, node     8       `ALERT' Reports that a node has failed
state was X                               
Report arbitrator results 2       `ALERT' There are eight different
                                          possible results for
                                          arbitration attempts:
                                          
                                             * Arbitration check
                                               failed--less than 1/2 nodes
                                               left
                                          
                                             * Arbitration check
                                               succeeded--node group
                                               majority
                                          
                                             * Arbitration check
                                               failed--missing node group
                                          
                                             * Network
                                               partitioning--arbitration
                                               required
                                          
                                             * Arbitration
                                               succeeded--affirmative
                                               response from node X
                                          
                                             * Arbitration failed -
                                               negative response from node
                                               X
                                          
                                             * Network partitioning - no
                                               arbitrator available
                                          
                                             * Network partitioning - no
                                               arbitrator configured
Completed copying a       10      `INFO'  
fragment                                  
Completed copying of      8       `INFO'  
dictionary information                    
Completed copying         8       `INFO'  
distribution information                  
Starting to copy          8       `INFO'  
fragments                                 
Completed copying all     8       `INFO'  
fragments                                 
GCP takeover started      7       `INFO'  
GCP takeover completed    7       `INFO'  
LCP takeover started      7       `INFO'  
LCP takeover completed    7       `INFO'  
(state = X)                               
Report whether an         6       `INFO'  There are seven different
arbitrator is found or                    possible outcomes when seeking
not                                       an arbitrator:
                                          
                                             * Management server restarts
                                               arbitration thread
                                               [state=X]
                                          
                                             * Prepare arbitrator node X
                                               [ticket=Y]
                                          
                                             * Receive arbitrator node X
                                               [ticket=Y]
                                          
                                             * Started arbitrator node X
                                               [ticket=Y]
                                          
                                             * Lost arbitrator node X -
                                               process failure [state=Y]
                                          
                                             * Lost arbitrator node X -
                                               process exit [state=Y]
                                          
                                             * Lost arbitrator node X
                                               <error msg> [state=Y]
*`STATISTICS' Events*

The following events are of a statistical nature. They provide
information such as numbers of transactions and other operations,
amount of data sent or received by individual nodes, and memory usage.

Event                     PrioritySeverityDescription
                                  Level   
Report job scheduling     9       `INFO'  Mean internal job scheduling
statistics                                statistics
Sent number of bytes      9       `INFO'  Mean number of bytes sent to
                                          node X
Received # of bytes       9       `INFO'  Mean number of bytes received
                                          from node X
Report transaction        8       `INFO'  Numbers of: transactions,
statistics                                commits, reads, simple reads,
                                          writes, concurrent operations,
                                          attribute information, and
                                          aborts
Report operations         8       `INFO'  Number of operations
Report table create       7       `INFO'  
Memory usage              5       `INFO'  Data and index memory usage
                                          (80%, 90%, and 100%)

*`ERROR' Events*

These events relate to Cluster errors and warnings. The presence of one
or more of these generally indicates that a major malfunction or
failure has occurred.

Event                     PrioritySeverityDescription
Dead due to missed        8       `ALERT' Node X declared `dead' due to
heartbeat                                 missed heartbeat
Transporter errors        2       ERROR   
Transporter warnings      8       `WARNING'
Missed heartbeats         8       `WARNING'Node X missed heartbeat #Y
General warning events    2       `WARNING'

*`INFO' Events*

These events provide general information about the state of the cluster
and activities associated with Cluster maintenance, such as logging and
heartbeat transmission.

Event                     PrioritySeverityDescription
Sent heartbeat            12      `INFO'  Heartbeat sent to node X
Create log bytes          11      `INFO'  Log part, log file, MB
General information       2       `INFO'  
events                                    


File: manual.info,  Node: mysql-cluster-log-statistics,  Prev: mysql-cluster-log-events,  Up: mysql-cluster-event-reports

17.5.5.3 Using `CLUSTERLOG STATISTICS' in the MySQL Cluster Management Client
.............................................................................

The *Note `NDB': mysql-cluster. management client's `CLUSTERLOG
STATISTICS' command can provide a number of useful statistics in its
output. Counters providing information about the state of the cluster
are updated at 5-second reporting intervals by the transaction
coordinator (TC) and the local query handler (LQH), and written to the
cluster log.

Transaction coordinator statistics

Each transaction has one transaction coordinator, which is chosen by
one of the following methods:

   * In a round-robin fashion

   * By communication proximity

*Note*:

You can determine which TC selection method is used for transactions
started from a given SQL node using the `ndb_optimized_node_selection'
system variable. For more information, see *Note
mysql-cluster-system-variables::.

All operations within the same transaction use the same transaction
coordinator, which reports the following statistics:

   * `Trans count'

     This is the number transactions started in the last interval using
     this TC as the transaction coordinator. Any of these transactions
     may have committed, have been aborted, or remain uncommitted at
     the end of the reporting interval.

     *Note*:

     Transactions do not migrate between TCs.

   * `Commit count'

     This is the number of transactions using this TC as the
     transaction coordinator that were committed in the last reporting
     interval. Because some transactions committed in this reporting
     interval may have started in a previous reporting interval, it is
     possible for `Commit count' to be greater than `Trans count'.

   * `Read count'

     This is the number of primary key read operations using this TC as
     the transaction coordinator that were started in the last
     reporting interval, including simple reads.  This count also
     includes reads performed as part of unique index operations. A
     unique index read operation generates 2 primary key read
     operations--1 for the hidden unique index table, and 1 for the
     table on which the read takes place.

   * `Simple read count'

     This is the number of simple read operations using this TC as the
     transaction coordinator that were started in the last reporting
     interval. This is a subset of `Read count'. Because the value of
     `Simple read count' is incremented at a different point in time
     from `Read count', it can lag behind `Read count' slightly, so it
     is conceivable that `Simple read count' is not equal to `Read
     count' for a given reporting interval, even if all reads made
     during that time were in fact simple reads.

   * `Write count'

     This is the number of primary key write operations using this TC
     as the transaction coordinator that were started in the last
     reporting interval. This includes all inserts, updates, writes and
     deletes, as well as writes performed as part of unique index
     operations.

     *Note*:

     A unique index update operation can generate multiple PK read and
     write operations on the index table and on the base table.

   * `AttrInfoCount'

     This is the number of 32-bit data words received in the last
     reporting interval for primary key operations using this TC as the
     transaction coordinator. For reads, this is proportional to the
     number of columns requested. For inserts and updates, this is
     proportional to the number of columns written, and the size of
     their data. For delete operations, this is usually zero. Unique
     index operations generate multiple PK operations and so increase
     this count. However, data words sent to describe the PK operation
     itself, and the key information sent, are _not_ counted here.
     Attribute information sent to describe columns to read for scans,
     or to describe ScanFilters, is also not counted in `AttrInfoCount'.

   * `Concurrent Operations'

     This is the number of primary key or scan operations using this TC
     as the transaction coordinator that were started during the last
     reporting interval but that were not completed. Operations
     increment this counter when they are started and decrement it when
     they are completed; this occurs after the transaction commits.
     Dirty reads and writes--as well as failed operations--decrement
     this counter. The maximum value that `Concurrent Operations' can
     have is the maximum number of operations that a TC block can
     support; currently, this is `(2 * MaxNoOfConcurrentOperations) +
     16 + MaxNoOfConcurrentTransactions'. (For more information about
     these configuration parameters, see the `Transaction Parameters'
     section of *Note mysql-cluster-ndbd-definition::.)

   * `Abort count'

     This is the number of transactions using this TC as the
     transaction coordinator that were aborted during the last
     reporting interval. Because some transactions that were aborted in
     the last reporting interval may have started in a previous
     reporting interval, `Abort count' can sometimes be greater than
     `Trans count'.

   * `Scans'

     This is the number of table scans using this TC as the transaction
     coordinator that were started during the last reporting interval.
     This does not include range scans (that is, ordered index scans).

   * `Range scans'

     This is the number of ordered index scans using this TC as the
     transaction coordinator that were started in the last reporting
     interval.

Local query handler statistics (`Operations')

There is 1 cluster event per local query handler block (that is, 1 per
data node process). Operations are recorded in the LQH where the data
they are operating on resides.

*Note*:

A single transaction may operate on data stored in multiple LQH blocks.

The `Operations' statistic provides the number of local operations
performed by this LQH block in the last reporting interval, and
includes all types of read and write operations (insert, update, write,
and delete operations). This also includes operations used to replicate
writes--for example, in a 2-replica cluster, the write to the primary
replica is recorded in the primary LQH, and the write to the backup
will be recorded in the backup LQH. Unique key operations may result in
multiple local operations; however, this does _not_ include local
operations generated as a result of a table scan or ordered index scan,
which are not counted.

Process scheduler statistics

In addition to the statistics reported by the transaction coordinator
and local query handler, each *Note `ndbd':
mysql-cluster-programs-ndbd. process has a scheduler which also
provides useful metrics relating to the performance of a MySQL Cluster.
This scheduler runs in an infinite loop; during each loop the scheduler
performs the following tasks:

  1. Read any incoming messages from sockets into a job buffer.

  2. Check whether there are any timed messages to be executed; if so,
     put these into the job buffer as well.

  3. Execute (in a loop) any messages in the job buffer.

  4. Send any distributed messages that were generated by executing the
     messages in the job buffer.

  5. Wait for any new incoming messages.

Process scheduler statistics include the following:

   * `Mean Loop Counter'

     This is the number of loops executed in the third step from the
     preceding list. This statistic increases in size as the
     utilization of the TCP/IP buffer improves. You can use this to
     monitor changes in performance as you add new data node processes.

   * `Mean send size' and `Mean receive size'

     These statistics enable you to gauge the efficiency of,
     respectively writes and reads between nodes. The values are given
     in bytes. Higher values mean a lower cost per byte sent or
     received; the maximum value is 64K.

To cause all cluster log statistics to be logged, you can use the
following command in the *Note `NDB': mysql-cluster.  management client:

     ndb_mgm> ALL CLUSTERLOG STATISTICS=15

*Note*:

Setting the threshold for `STATISTICS' to 15 causes the cluster log to
become very verbose, and to grow quite rapidly in size, in direct
proportion to the number of cluster nodes and the amount of activity in
the MySQL Cluster.

For more information about MySQL Cluster management client commands
relating to logging and reporting, see *Note
mysql-cluster-logging-management-commands::.


File: manual.info,  Node: mysql-cluster-logs-ndb-messages,  Next: mysql-cluster-single-user-mode,  Prev: mysql-cluster-event-reports,  Up: mysql-cluster-management

17.5.6 MySQL Cluster Log Messages
---------------------------------

* Menu:

* mysql-cluster-logs-cluster-log::  MySQL Cluster: Messages in the Cluster Log
* mysql-cluster-ndb-transporter-errors::  MySQL Cluster: `NDB' Transporter Errors

This section contains information about the messages written to the
cluster log in response to different cluster log events. It provides
additional, more specific information on *Note `NDB': mysql-cluster.
transporter errors.


File: manual.info,  Node: mysql-cluster-logs-cluster-log,  Next: mysql-cluster-ndb-transporter-errors,  Prev: mysql-cluster-logs-ndb-messages,  Up: mysql-cluster-logs-ndb-messages

17.5.6.1 MySQL Cluster: Messages in the Cluster Log
...................................................

The following table lists the most common *Note `NDB': mysql-cluster.
cluster log messages. For information about the cluster log, log
events, and event types, see *Note mysql-cluster-event-reports::. These
log messages also correspond to log event types in the MGM API; see The
`Ndb_logevent_type' Type
(http://dev.mysql.com/doc/ndbapi/en/mgm-ndb-logevent-type.html), for
related information of interest to Cluster API developers.

Log Message                                 Event Name
                                            
`Node MGM_NODE_ID: Node DATA_NODE_ID        `Connected'
Connected'                                  
                                            Event Type
Description                                 
                                            `Connection'
The data node having node ID NODE_ID has    
connected to the management server (node    Priority
MGM_NODE_ID).                               
                                            8
                                            
                                            Severity
                                            
                                            `INFO'
Log Message                                 Event Name
                                            
`Node MGM_NODE_ID: Node DATA_NODE_ID        `Disconnected'
Disconnected'                               
                                            Event Type
Description                                 
                                            `Connection'
The data node having node ID DATA_NODE_ID   
has disconnected from the management        Priority
server (node MGM_NODE_ID).                  
                                            8
                                            
                                            Severity
                                            
                                            `ALERT'
Log Message                                 Event Name
                                            
`Node DATA_NODE_ID: Communication to Node   `CommunicationClosed'
API_NODE_ID closed'                         
                                            Event Type
Description                                 
                                            `Connection'
The API node or SQL node having node ID     
API_NODE_ID is no longer communicating      Priority
with data node DATA_NODE_ID.                
                                            8
                                            
                                            Severity
                                            
                                            `INFO'
Log Message                                 Event Name
                                            
`Node DATA_NODE_ID: Communication to Node   `CommunicationOpened'
API_NODE_ID opened'                         
                                            Event Type
Description                                 
                                            `Connection'
The API node or SQL node having node ID     
API_NODE_ID is now communicating with data  Priority
node DATA_NODE_ID.                          
                                            8
                                            
                                            Severity
                                            
                                            `INFO'
Log Message                                 Event Name
                                            
`Node MGM_NODE_ID: Node API_NODE_ID: API    `ConnectedApiVersion'
VERSION'                                    
                                            Event Type
Description                                 
                                            `Connection'
The API node having node ID API_NODE_ID     
has connected to management node            Priority
MGM_NODE_ID using *Note `NDB':              
mysql-cluster. API version VERSION          8
(generally the same as the MySQL version    
number).                                    Severity
                                            
                                            `INFO'
Log Message                                 Event Name
                                            
`Node NODE_ID: Global checkpoint GCI        `GlobalCheckpointStarted'
started'                                    
                                            Event Type
Description                                 
                                            `Checkpoint'
A global checkpoint with the ID GCI has     
been started; node NODE_ID is the master    Priority
responsible for this global checkpoint.     
                                            9
                                            
                                            Severity
                                            
                                            `INFO'
Log Message                                 Event Name
                                            
`Node NODE_ID: Global checkpoint GCI        `GlobalCheckpointCompleted'
completed'                                  
                                            Event Type
Description                                 
                                            `Checkpoint'
The global checkpoint having the ID GCI     
has been completed; node NODE_ID was the    Priority
master responsible for this global          
checkpoint.                                 10
                                            
                                            Severity
                                            
                                            `INFO'
Log Message                                 Event Name
                                            
`Node NODE_ID: Local checkpoint LCP         `LocalCheckpointStarted'
started. Keep GCI = CURRENT_GCI oldest      
restorable GCI = OLD_GCI'                   Event Type
                                            
Description                                 `Checkpoint'
                                            
The local checkpoint having sequence ID     Priority
LCP has been started on node NODE_ID. The   
most recent GCI that can be used has the    7
index CURRENT_GCI, and the oldest GCI from  
which the cluster can be restored has the   Severity
index OLD_GCI.                              
                                            `INFO'
Log Message                                 Event Name
                                            
`Node NODE_ID: Local checkpoint LCP         `LocalCheckpointCompleted'
completed'                                  
                                            Event Type
Description                                 
                                            `Checkpoint'
The local checkpoint having sequence ID     
LCP on node NODE_ID has been completed.     Priority
                                            
                                            8
                                            
                                            Severity
                                            
                                            `INFO'
Log Message                                 Event Name
                                            
`Node NODE_ID: Local Checkpoint stopped in  `LCPStoppedInCalcKeepGci'
CALCULATED_KEEP_GCI'                        
                                            Event Type
Description                                 
                                            `Checkpoint'
The node was unable to determine the most   
recent usable GCI.                          Priority
                                            
                                            0
                                            
                                            Severity
                                            
                                            `ALERT'
Log Message                                 Event Name
                                            
`Node NODE_ID: Table ID = TABLE_ID,         `LCPFragmentCompleted'
fragment ID = FRAGMENT_ID has completed     
LCP on Node NODE_ID maxGciStarted:          Event Type
STARTED_GCI maxGciCompleted: COMPLETED_GCI' 
                                            `Checkpoint'
Description                                 
                                            Priority
A table fragment has been checkpointed to   
disk on node NODE_ID. The GCI in progress   11
has the index STARTED_GCI, and the most     
recent GCI to have been completed has the   Severity
index COMPLETED_GCI.                        
                                            `INFO'
Log Message                                 Event Name
                                            
`Node NODE_ID: ACC Blocked NUM_1 and TUP    `UndoLogBlocked'
Blocked NUM_2 times last second'            
                                            Event Type
Description                                 
                                            `Checkpoint'
Undo logging is blocked because the log     
buffer is close to overflowing.             Priority
                                            
                                            7
                                            
                                            Severity
                                            
                                            `INFO'
Log Message                                 Event Name
                                            
`Node NODE_ID: Start initiated VERSION'     `NDBStartStarted'
                                            
Description                                 Event Type
                                            
Data node NODE_ID, running *Note `NDB':     `StartUp'
mysql-cluster. version VERSION, is          
beginning its startup process.              Priority
                                            
                                            1
                                            
                                            Severity
                                            
                                            `INFO'
Log Message                                 Event Name
                                            
`Node NODE_ID: Started VERSION'             `NDBStartCompleted'
                                            
Description                                 Event Type
                                            
Data node NODE_ID, running *Note `NDB':     `StartUp'
mysql-cluster. version VERSION, has started 
successfully.                               Priority
                                            
                                            1
                                            
                                            Severity
                                            
                                            `INFO'
Log Message                                 Event Name
                                            
`Node NODE_ID: STTORRY received after       `STTORRYRecieved'
restart finished'                           
                                            Event Type
Description                                 
                                            `StartUp'
The node has received a signal indicating   
that a cluster restart has completed.       Priority
                                            
                                            15
                                            
                                            Severity
                                            
                                            `INFO'
Log Message                                 Event Name
                                            
`Node NODE_ID: Start phase PHASE completed  `StartPhaseCompleted'
(TYPE)'                                     
                                            Event Type
Description                                 
                                            `StartUp'
The node has completed start phase PHASE    
of a TYPE start. For a listing of start     Priority
phases, see *Note                           
mysql-cluster-start-phases::.  (TYPE is     4
one of `initial', `system', `node',         
`initial node', or `<Unknown>'.)            Severity
                                            
                                            `INFO'
Log Message                                 Event Name
                                            
`Node NODE_ID: CM_REGCONF president =       `CM_REGCONF'
PRESIDENT_ID, own Node = OWN_ID, our        
dynamic id = DYNAMIC_ID'                    Event Type
                                            
Description                                 `StartUp'
                                            
Node PRESIDENT_ID has been selected as      Priority
`president'.  OWN_ID and DYNAMIC_ID should  
always be the same as the ID (NODE_ID) of   3
the reporting node.                         
                                            Severity
                                            
                                            `INFO'
Log Message                                 Event Name
                                            
`Node NODE_ID: CM_REGREF from Node          `CM_REGREF'
PRESIDENT_ID to our Node NODE_ID. Cause =   
CAUSE'                                      Event Type
                                            
Description                                 `StartUp'
                                            
The reporting node (ID NODE_ID) was unable  Priority
to accept node PRESIDENT_ID as president.   
The CAUSE of the problem is given as one of 8
`Busy', `Election with wait = false', `Not  
president', `Election without selecting new Severity
candidate', or `No such cause'.             
                                            `INFO'
Log Message                                 Event Name
                                            
`Node NODE_ID: We are Node OWN_ID with      `FIND_NEIGHBOURS'
dynamic ID DYNAMIC_ID, our left neighbour   
is Node ID_1, our right is Node ID_2'       Event Type
                                            
Description                                 `StartUp'
                                            
The node has discovered its neighboring     Priority
nodes in the cluster (node ID_1 and node    
ID_2).  NODE_ID, OWN_ID, and DYNAMIC_ID     8
should always be the same; if they are      
not, this indicates a serious               Severity
misconfiguration of the cluster nodes.      
                                            `INFO'
Log Message                                 Event Name
                                            
`Node NODE_ID: TYPE shutdown initiated'     `NDBStopStarted'
                                            
Description                                 Event Type
                                            
The node has received a shutdown signal.    `StartUp'
The TYPE of shutdown is either `Cluster' or 
`Node'.                                     Priority
                                            
                                            1
                                            
                                            Severity
                                            
                                            `INFO'
Log Message                                 Event Name
                                            
`Node NODE_ID: Node shutdown completed '[`, `NDBStopCompleted'
ACTION'] [`Initiated by signal SIGNAL.']    
                                            Event Type
Description                                 
                                            `StartUp'
The node has been shut down. This report    
may include an ACTION, which if present is  Priority
one of `restarting', `no start', or         
`initial'. The report may also include a    1
reference to an *Note `NDB':                
mysql-cluster. Protocol SIGNAL; for         Severity
possible signals, refer to Operations and   
Signals                                     `INFO'
(http://dev.mysql.com/doc/ndbapi/en/ndb-internals-ndb-protocol-operations-signals.html).
Log Message                                 Event Name
                                            
`Node NODE_ID: Forced node shutdown         `NDBStopForced'
completed '[`, action']`.' [`Occured        
during startphase START_PHASE.'] [`         Event Type
Initiated by SIGNAL.'] [`Caused by error    
ERROR_CODE:                                 `StartUp'
'ERROR_MESSAGE(ERROR_CLASSIFICATION).       
ERROR_STATUS'.' [`(extra info               Priority
EXTRA_CODE)']]                              
                                            1
Description                                 
                                            Severity
The node has been forcibly shut down. The   
ACTION (one of `restarting', `no start',    `ALERT'
or `initial') subsequently being taken, if  
any, is also reported.  If the shutdown     
occurred while the node was starting, the   
report includes the START_PHASE during      
which the node failed. If this was a        
result of a SIGNAL sent to the node, this   
information is also provided (see           
Operations and Signals                      
(http://dev.mysql.com/doc/ndbapi/en/ndb-internals-ndb-protocol-operations-signals.html),
for more information). If the error         
causing the failure is known, this is also  
included; for more information about *Note  
`NDB': mysql-cluster.  error messages and   
classifications, see MySQL Cluster API      
Errors                                      
(http://dev.mysql.com/doc/ndbapi/en/ndb-errors.html).
Log Message                                 Event Name
                                            
`Node NODE_ID: Node shutdown aborted'       `NDBStopAborted'
                                            
Description                                 Event Type
                                            
The node shutdown process was aborted by    `StartUp'
the user.                                   
                                            Priority
                                            
                                            1
                                            
                                            Severity
                                            
                                            `INFO'
Log Message                                 Event Name
                                            
`Node NODE_ID: StartLog: [GCI Keep:         `StartREDOLog'
KEEP_POS LastCompleted: LAST_POS            
NewestRestorable: RESTORE_POS]'             Event Type
                                            
Description                                 `StartUp'
                                            
This reports global checkpoints referenced  Priority
during a node start. The redo log prior to  
KEEP_POS is dropped.  LAST_POS is the last  4
global checkpoint in which data node the    
participated; RESTORE_POS is the global     Severity
checkpoint which is actually used to        
restore all data nodes.                     `INFO'
Log Message                                 Event Name
                                            
STARTUP_MESSAGE [_Listed separately; see    `StartReport'
below._]                                    
                                            Event Type
Description                                 
                                            `StartUp'
There are a number of possible startup      
messages that can be logged under           Priority
different circumstances.                    
                                            4
                                            
                                            Severity
                                            
                                            `INFO'
Log Message                                 Event Name
                                            
`Node NODE_ID: Node restart completed copy  `NR_CopyDict'
of dictionary information'                  
                                            Event Type
Description                                 
                                            `NodeRestart'
Copying of data dictionary information to   
the restarted node has been completed.      Priority
                                            
                                            8
                                            
                                            Severity
                                            
                                            `INFO'
Log Message                                 Event Name
                                            
`Node NODE_ID: Node restart completed copy  `NR_CopyDistr'
of distribution information'                
                                            Event Type
Description                                 
                                            `NodeRestart'
Copying of data distribution information    
to the restarted node has been completed.   Priority
                                            
                                            8
                                            
                                            Severity
                                            
                                            `INFO'
Log Message                                 Event Name
                                            
`Node NODE_ID: Node restart starting to     `NR_CopyFragsStarted'
copy the fragments to Node NODE_ID'         
                                            Event Type
Description                                 
                                            `NodeRestart'
Copy of fragments to starting data node     
NODE_ID has begun                           Priority
                                            
                                            8
                                            
                                            Severity
                                            
                                            `INFO'
Log Message                                 Event Name
                                            
`Node NODE_ID: Table ID = TABLE_ID,         `NR_CopyFragDone'
fragment ID = FRAGMENT_ID have been copied  
to Node NODE_ID'                            Event Type
                                            
Description                                 `NodeRestart'
                                            
Fragment FRAGMENT_ID from table TABLE_ID    Priority
has been copied to data node NODE_ID        
                                            10
                                            
                                            Severity
                                            
                                            `INFO'
Log Message                                 Event Name
                                            
`Node NODE_ID: Node restart completed       `NR_CopyFragsCompleted'
copying the fragments to Node NODE_ID'      
                                            Event Type
Description                                 
                                            `NodeRestart'
Copying of all table fragments to           
restarting data node NODE_ID has been       Priority
completed                                   
                                            8
                                            
                                            Severity
                                            
                                            `INFO'
Log Message                                 Event Name
                                            
Any of the following:                       `NodeFailCompleted'
                                            
  1. `Node NODE_ID: Node NODE1_ID completed Event Type
     failure of Node NODE2_ID'              
                                            `NodeRestart'
  2. `All nodes completed failure of Node   
     NODE_ID'                               Priority
                                            
  3. `Node failure of NODE_IDBLOCK          8
     completed'                             
Description                                 Severity
                                            
One of the following (each corresponding    `ALERT'
to the same-numbered message listed above): 
                                            
  1. Data node NODE1_ID has detected the    
     failure of data node NODE2_ID          
                                            
  2. All (remaining) data nodes have        
     detected the failure of data node      
     NODE_ID                                
                                            
  3. The failure of data node NODE_ID has   
     been detected in the BLOCK*Note        
     `NDB': mysql-cluster.  kernel block,   
     where block is 1 of `DBTC', `DBDICT',  
     `DBDIH', or `DBLQH'; for more          
     information, see `NDB' Kernel Blocks   
     (http://dev.mysql.com/doc/ndbapi/en/ndb-internals-kernel-blocks.html)
Log Message                                 Event Name
                                            
`Node MGM_NODE_ID: Node DATA_NODE_ID has    `NODE_FAILREP'
failed.  The Node state at failure was      
STATE_CODE'                                 Event Type
                                            
Description                                 `NodeRestart'
                                            
A data node has failed. Its state at the    Priority
time of failure is described by an          
arbitration state code STATE_CODE: possible 8
state code values can be found in the file  
`include/kernel/signaldata/ArbitSignalData.hpp'.Severity
                                            
                                            `ALERT'
Log Message                                 Event Name
                                            
`President restarts arbitration thread      `ArbitState'
[state=STATE_CODE]' or `Prepare arbitrator  
node NODE_ID [ticket=TICKET_ID]' or         Event Type
`Receive arbitrator node NODE_ID            
[ticket=TICKET_ID]' or `Started arbitrator  `NodeRestart'
node NODE_ID [ticket=TICKET_ID]' or `Lost   
arbitrator node NODE_ID - process failure   Priority
[state=STATE_CODE]' or `Lost arbitrator     
node NODE_ID - process exit                 6
[state=STATE_CODE]' or `Lost arbitrator     
node NODE_ID - ERROR_MESSAGE                Severity
[state=STATE_CODE]'                         
                                            `INFO'
Description                                 
                                            
This is a report on the current state and   
progress of arbitration in the cluster.     
NODE_ID is the node ID of the management    
node or SQL node selected as the            
arbitrator. STATE_CODE is an arbitration    
state code, as found in                     
`include/kernel/signaldata/ArbitSignalData.hpp'.
When an error has occurred, an              
ERROR_MESSAGE, also defined in              
`ArbitSignalData.hpp', is provided.         
TICKET_ID is a unique identifier handed     
out by the arbitrator when it is selected   
to all the nodes that participated in its   
selection; this is used to ensure that      
each node requesting arbitration was one    
of the nodes that took part in the          
selection process.                          
Log Message                                 Event Name
                                            
`Arbitration check lost - less than 1/2     `ArbitResult'
nodes left' or `Arbitration check won -     
all node groups and more than 1/2 nodes     Event Type
left' or `Arbitration check won - node      
group majority' or `Arbitration check lost  `NodeRestart'
- missing node group' or `Network           
partitioning - arbitration required' or     Priority
`Arbitration won - positive reply from node 
NODE_ID' or `Arbitration lost - negative    2
reply from node NODE_ID' or `Network        
partitioning - no arbitrator available' or  Severity
`Network partitioning - no arbitrator       
configured' or `Arbitration failure -       `ALERT'
ERROR_MESSAGE [state=STATE_CODE]'           
                                            
Description                                 
                                            
This message reports on the result of       
arbitration.  In the event of arbitration   
failure, an ERROR_MESSAGE and an            
arbitration STATE_CODE are provided;        
definitions for both of these are found in  
`include/kernel/signaldata/ArbitSignalData.hpp'.
Log Message                                 Event Name
                                            
`Node NODE_ID: GCP Take over started'       `GCP_TakeoverStarted'
                                            
Description                                 Event Type
                                            
This node is attempting to assume           `NodeRestart'
responsibility for the next global          
checkpoint (that is, it is becoming the     Priority
master node)                                
                                            7
                                            
                                            Severity
                                            
                                            `INFO'
Log Message                                 Event Name
                                            
`Node NODE_ID: GCP Take over completed'     `GCP_TakeoverCompleted'
                                            
Description                                 Event Type
                                            
This node has become the master, and has    `NodeRestart'
assumed responsibility for the next global  
checkpoint                                  Priority
                                            
                                            7
                                            
                                            Severity
                                            
                                            `INFO'
Log Message                                 Event Name
                                            
`Node NODE_ID: LCP Take over started'       `LCP_TakeoverStarted'
                                            
Description                                 Event Type
                                            
This node is attempting to assume           `NodeRestart'
responsibility for the next set of local    
checkpoints (that is, it is becoming the    Priority
master node)                                
                                            7
                                            
                                            Severity
                                            
                                            `INFO'
Log Message                                 Event Name
                                            
`Node NODE_ID: LCP Take over completed'     `LCP_TakeoverCompleted'
                                            
Description                                 Event Type
                                            
This node has become the master, and has    `NodeRestart'
assumed responsibility for the next set of  
local checkpoints                           Priority
                                            
                                            7
                                            
                                            Severity
                                            
                                            `INFO'
Log Message                                 Event Name
                                            
`Node NODE_ID: Trans. Count =               `TransReportCounters'
TRANSACTIONS, Commit Count = COMMITS, Read  
Count = READS, Simple Read Count =          Event Type
SIMPLE_READS, Write Count = WRITES,         
AttrInfo Count = ATTRINFO_OBJECTS,          `Statistic'
Concurrent Operations =                     
CONCURRENT_OPERATIONS, Abort Count =        Priority
ABORTS, Scans = SCANS, Range scans =        
RANGE_SCANS'                                8
                                            
Description                                 Severity
                                            
This report of transaction activity is      `INFO'
given approximately once every 10 seconds   
Log Message                                 Event Name
                                            
`Node NODE_ID: Operations=OPERATIONS'       `OperationReportCounters'
                                            
Description                                 Event Type
                                            
Number of operations performed by this      `Statistic'
node, provided approximately once every 10  
seconds                                     Priority
                                            
                                            8
                                            
                                            Severity
                                            
                                            `INFO'
Log Message                                 Event Name
                                            
`Node NODE_ID: Table with ID = TABLE_ID     `TableCreated'
created'                                    
                                            Event Type
Description                                 
                                            `Statistic'
A table having the table ID shown has been  
created                                     Priority
                                            
                                            7
                                            
                                            Severity
                                            
                                            `INFO'
Log Message                                 Event Name
                                            
`Node NODE_ID: Mean loop Counter in doJob   `JobStatistic'
last 8192 times = COUNT'                    
                                            Event Type
Description                                 
                                            `Statistic'
                                            
                                            Priority
                                            
                                            9
                                            
                                            Severity
                                            
                                            `INFO'
Log Message                                 Event Name
                                            
`Mean send size to Node = NODE_ID last      `SendBytesStatistic'
4096 sends = BYTES bytes'                   
                                            Event Type
Description                                 
                                            `Statistic'
This node is sending an average of BYTES    
bytes per send to node NODE_ID              Priority
                                            
                                            9
                                            
                                            Severity
                                            
                                            `INFO'
Log Message                                 Event Name
                                            
`Mean receive size to Node = NODE_ID last   `ReceiveBytesStatistic'
4096 sends = BYTES bytes'                   
                                            Event Type
Description                                 
                                            `Statistic'
This node is receiving an average of BYTES  
of data each time it receives data from     Priority
node NODE_ID                                
                                            9
                                            
                                            Severity
                                            
                                            `INFO'
Log Message                                 Event Name
                                            
`Node NODE_ID: Data usage is                `MemoryUsage'
DATA_MEMORY_PERCENTAGE% (DATA_PAGES_USED    
32K pages of total DATA_PAGES_TOTAL)' /     Event Type
`Node NODE_ID: Index usage is               
INDEX_MEMORY_PERCENTAGE% (INDEX_PAGES_USED  `Statistic'
8K pages of total INDEX_PAGES_TOTAL) '      
                                            Priority
Description                                 
                                            5
This report is generated when a `DUMP       
1000' command is issued in the cluster      Severity
management client; for more information,    
see `DUMP 1000'                             `INFO'
(http://dev.mysql.com/doc/ndbapi/en/ndb-internals-dump-command-1000.html),
in MySQL Cluster Internals                  
(http://dev.mysql.com/doc/ndbapi/en/ndb-internals.html)
Log Message                                 Event Name
                                            
`Node NODE1_ID: Transporter to node         `TransporterError'
NODE2_ID reported error ERROR_CODE:         
ERROR_MESSAGE'                              Event Type
                                            
Description                                 `Error'
                                            
A transporter error occurred while          Priority
communicating with node NODE2_ID; for a     
listing of transporter error codes and      2
messages, see `NDB' Transporter Errors      
(http://dev.mysql.com/doc/ndbapi/en/ndb-transporter-errors.html),Severity
in MySQL Cluster Internals                  
(http://dev.mysql.com/doc/ndbapi/en/ndb-internals.html)`ERROR'
Log Message                                 Event Name
                                            
`Node NODE1_ID: Transporter to node         `TransporterWarning'
NODE2_ID reported error ERROR_CODE:         
ERROR_MESSAGE'                              Event Type
                                            
Description                                 `Error'
                                            
A warning of a potential transporter        Priority
problem while communicating with node       
NODE2_ID; for a listing of transporter      8
error codes and messages, see `NDB'         
Transporter Errors                          Severity
(http://dev.mysql.com/doc/ndbapi/en/ndb-transporter-errors.html),
for more information                        `WARNING'
Log Message                                 Event Name
                                            
`Node NODE1_ID: Node NODE2_ID missed        `MissedHeartbeat'
heartbeat HEARTBEAT_ID'                     
                                            Event Type
Description                                 
                                            `Error'
This node missed a heartbeat from node      
NODE2_ID                                    Priority
                                            
                                            8
                                            
                                            Severity
                                            
                                            `WARNING'
Log Message                                 Event Name
                                            
`Node NODE1_ID: Node NODE2_ID declared      `DeadDueToHeartbeat'
dead due to missed heartbeat'               
                                            Event Type
Description                                 
                                            `Error'
This node has missed at least 3 heartbeats  
from node NODE2_ID, and so has declared     Priority
that node `dead'                            
                                            8
                                            
                                            Severity
                                            
                                            `ALERT'
Log Message                                 Event Name
                                            
`Node NODE1_ID: Node Sent Heartbeat to      `SentHeartbeat'
node = NODE2_ID'                            
                                            Event Type
Description                                 
                                            `Info'
This node has sent a heartbeat to node      
NODE2_ID                                    Priority
                                            
                                            12
                                            
                                            Severity
                                            
                                            `INFO'
Log Message                                 Event Name
                                            
`Node NODE_ID: Event buffer status:         `EventBufferStatus'
used=BYTES_USED (PERCENT_USED%)             
alloc=BYTES_ALLOCATED (PERCENT_AVAILABLE%)  Event Type
max=BYTES_AVAILABLE                         
apply_gci=LATEST_RESTORABLE_GCI             `Info'
latest_gci=LATEST_GCI'                      
                                            Priority
Description                                 
                                            7
This report is seen during heavy event      
buffer usage, for example, when many        Severity
updates are being applied in a relatively   
short period of time; the report shows the  `INFO'
number of bytes and the percentage of event 
buffer memory used, the bytes allocated and 
percentage still available, and the latest  
and latest restorable global checkpoints    
Log Message                                 Event Name
                                            
`Node NODE_ID: Entering single user mode',  `SingleUser'
`Node NODE_ID: Entered single user mode     
Node API_NODE_ID has exclusive access',     Event Type
`Node NODE_ID: Entering single user mode'   
                                            `Info'
Description                                 
                                            Priority
These reports are written to the cluster    
log when entering and exiting single user   7
mode; API_NODE_ID is the node ID of the     
API or SQL having exclusive access to the   Severity
cluster (for more information, see *Note    
mysql-cluster-single-user-mode::); the      `INFO'
message `Unknown single user report         
API_NODE_ID' indicates an error has taken   
place and should never be seen in normal    
operation                                   
Log Message                                 Event Name
                                            
`Node NODE_ID: Backup BACKUP_ID started     `BackupStarted'
from node MGM_NODE_ID'                      
                                            Event Type
Description                                 
                                            `Backup'
A backup has been started using the         
management node having MGM_NODE_ID; this    Priority
message is also displayed in the cluster    
management client when the `START BACKUP'   7
command is issued; for more information,    
see *Note                                   Severity
mysql-cluster-backup-using-management-client::
                                            `INFO'
Log Message                                 Event Name
                                            
`Node NODE_ID: Backup BACKUP_ID started     `BackupCompleted'
from node MGM_NODE_ID completed. StartGCP:  
START_GCP StopGCP: STOP_GCP #Records:       Event Type
RECORDS #LogRecords: LOG_RECORDS Data:      
DATA_BYTES bytes Log: LOG_BYTES bytes'      `Backup'
                                            
Description                                 Priority
                                            
The backup having the ID BACKUP_ID has been 7
completed; for more information, see *Note  
mysql-cluster-backup-using-management-client::Severity
                                            
                                            `INFO'
Log Message                                 Event Name
                                            
`Node NODE_ID: Backup request from          `BackupFailedToStart'
MGM_NODE_ID failed to start. Error:         
ERROR_CODE'                                 Event Type
                                            
Description                                 `Backup'
                                            
The backup failed to start; for error       Priority
codes, see MGM`' API Errors                 
(http://dev.mysql.com/doc/ndbapi/en/mgm-errors.html)7
                                            
                                            Severity
                                            
                                            `ALERT'
Log Message                                 Event Name
                                            
`Node NODE_ID: Backup BACKUP_ID started     `BackupAborted'
from MGM_NODE_ID has been aborted. Error:   
ERROR_CODE'                                 Event Type
                                            
Description                                 `Backup'
                                            
The backup was terminated after starting,   Priority
possibly due to user intervention           
                                            7
                                            
                                            Severity
                                            
                                            `ALERT'


File: manual.info,  Node: mysql-cluster-ndb-transporter-errors,  Prev: mysql-cluster-logs-cluster-log,  Up: mysql-cluster-logs-ndb-messages

17.5.6.2 MySQL Cluster: `NDB' Transporter Errors
................................................

This section lists error codes, names, and messages that are written to
the cluster log in the event of transporter errors.

Error   Error Name                                  Error Text
Code                                                
0x00    TE_NO_ERROR                                 `No error'
0x01    TE_ERROR_CLOSING_SOCKET                     `Error found during
                                                    closing of socket'
0x02    TE_ERROR_IN_SELECT_BEFORE_ACCEPT            `Error found before
                                                    accept. The
                                                    transporter will
                                                    retry'
0x03    TE_INVALID_MESSAGE_LENGTH                   `Error found in
                                                    message (invalid
                                                    message length)'
0x04    TE_INVALID_CHECKSUM                         `Error found in
                                                    message (checksum)'
0x05    TE_COULD_NOT_CREATE_SOCKET                  `Error found while
                                                    creating socket(can't
                                                    create socket)'
0x06    TE_COULD_NOT_BIND_SOCKET                    `Error found while
                                                    binding server socket'
0x07    TE_LISTEN_FAILED                            `Error found while
                                                    listening to server
                                                    socket'
0x08    TE_ACCEPT_RETURN_ERROR                      `Error found during
                                                    accept(accept return
                                                    error)'
0x0b    TE_SHM_DISCONNECT                           `The remote node has
                                                    disconnected'
0x0c    TE_SHM_IPC_STAT                             `Unable to check shm
                                                    segment'
0x0d    TE_SHM_UNABLE_TO_CREATE_SEGMENT             `Unable to create shm
                                                    segment'
0x0e    TE_SHM_UNABLE_TO_ATTACH_SEGMENT             `Unable to attach shm
                                                    segment'
0x0f    TE_SHM_UNABLE_TO_REMOVE_SEGMENT             `Unable to remove shm
                                                    segment'
0x10    TE_TOO_SMALL_SIGID                          `Sig ID too small'
0x11    TE_TOO_LARGE_SIGID                          `Sig ID too large'
0x12    TE_WAIT_STACK_FULL                          `Wait stack was full'
0x13    TE_RECEIVE_BUFFER_FULL                      `Receive buffer was
                                                    full'
0x14    TE_SIGNAL_LOST_SEND_BUFFER_FULL             `Send buffer was
                                                    full,and trying to
                                                    force send fails'
0x15    TE_SIGNAL_LOST                              `Send failed for
                                                    unknown reason(signal
                                                    lost)'
0x16    TE_SEND_BUFFER_FULL                         `The send buffer was
                                                    full, but sleeping
                                                    for a while solved'
0x0017  TE_SCI_LINK_ERROR                           `There is no link
                                                    from this node to the
                                                    switch'
0x18    TE_SCI_UNABLE_TO_START_SEQUENCE             `Could not start a
                                                    sequence, because
                                                    system resources are
                                                    exumed or no sequence
                                                    has been created'
0x19    TE_SCI_UNABLE_TO_REMOVE_SEQUENCE            `Could not remove a
                                                    sequence'
0x1a    TE_SCI_UNABLE_TO_CREATE_SEQUENCE            `Could not create a
                                                    sequence, because
                                                    system resources are
                                                    exempted. Must reboot'
0x1b    TE_SCI_UNRECOVERABLE_DATA_TFX_ERROR         `Tried to send data
                                                    on redundant link but
                                                    failed'
0x1c    TE_SCI_CANNOT_INIT_LOCALSEGMENT             `Cannot initialize
                                                    local segment'
0x1d    TE_SCI_CANNOT_MAP_REMOTESEGMENT             `Cannot map remote
                                                    segment'
0x1e    TE_SCI_UNABLE_TO_UNMAP_SEGMENT              `Cannot free the
                                                    resources used by
                                                    this segment (step 1)'
0x1f    TE_SCI_UNABLE_TO_REMOVE_SEGMENT             `Cannot free the
                                                    resources used by
                                                    this segment (step 2)'
0x20    TE_SCI_UNABLE_TO_DISCONNECT_SEGMENT         `Cannot disconnect
                                                    from a remote segment'
0x21    TE_SHM_IPC_PERMANENT                        `Shm ipc Permanent
                                                    error'
0x22    TE_SCI_UNABLE_TO_CLOSE_CHANNEL              `Unable to close the
                                                    sci channel and the
                                                    resources allocated'


File: manual.info,  Node: mysql-cluster-single-user-mode,  Next: mysql-cluster-sql-statements,  Prev: mysql-cluster-logs-ndb-messages,  Up: mysql-cluster-management

17.5.7 MySQL Cluster Single User Mode
-------------------------------------

_Single user mode_ enables the database administrator to restrict
access to the database system to a single API node, such as a MySQL
server (SQL node) or an instance of *Note `ndb_restore':
mysql-cluster-programs-ndb-restore. When entering single user mode,
connections to all other API nodes are closed gracefully and all
running transactions are aborted. No new transactions are permitted to
start.

Once the cluster has entered single user mode, only the designated API
node is granted access to the database.

You can use the `ALL STATUS' command to see when the cluster has
entered single user mode.

Example:

     ndb_mgm> ENTER SINGLE USER MODE 5

After this command has executed and the cluster has entered single user
mode, the API node whose node ID is `5' becomes the cluster's only
permitted user.

The node specified in the preceding command must be an API node;
attempting to specify any other type of node will be rejected.

*Note*:

When the preceding command is invoked, all transactions running on the
designated node are aborted, the connection is closed, and the server
must be restarted.

The command `EXIT SINGLE USER MODE' changes the state of the cluster's
data nodes from single user mode to normal mode. API nodes--such as
MySQL Servers--waiting for a connection (that is, waiting for the
cluster to become ready and available), are again permitted to connect.
The API node denoted as the single-user node continues to run (if still
connected) during and after the state change.

Example:

     ndb_mgm> EXIT SINGLE USER MODE

There are two recommended ways to handle a node failure when running in
single user mode:

   * Method 1:

       1. Finish all single user mode transactions

       2. Issue the `EXIT SINGLE USER MODE' command

       3. Restart the cluster's data nodes

   * Method 2:

     Restart database nodes prior to entering single user mode.


File: manual.info,  Node: mysql-cluster-sql-statements,  Next: mysql-cluster-security,  Prev: mysql-cluster-single-user-mode,  Up: mysql-cluster-management

17.5.8 Quick Reference: MySQL Cluster SQL Statements
----------------------------------------------------

This section discusses several SQL statements that can prove useful in
managing and monitoring a MySQL server that is connected to a MySQL
Cluster, and in some cases provide information about the cluster itself.

   * *Note `SHOW ENGINE NDB STATUS': show-engine, *Note `SHOW ENGINE
     NDBCLUSTER STATUS': show-engine.

     The output of this statement contains information about the
     server's connection to the cluster, creation and usage of MySQL
     Cluster objects, and binary logging for MySQL Cluster replication.

     See *Note show-engine::, for a usage example and more detailed
     information.

   * `SHOW ENGINES [LIKE 'NDB%']'

     This statement can be used to determine whether or not clustering
     support is enabled in the MySQL server, and if so, whether it is
     active.

     See *Note show-engines::, for more detailed information.

   * `SHOW VARIABLES LIKE 'NDB%''

     This statement provides a list of most server system variables
     relating to the *Note `NDB': mysql-cluster. storage engine, and
     their values, as shown here:

          mysql> SHOW VARIABLES LIKE 'NDB%';
          +-------------------------------------+-------+
          | Variable_name                       | Value |
          +-------------------------------------+-------+
          | ndb_autoincrement_prefetch_sz       | 32    |
          | ndb_cache_check_time                | 0     |
          | ndb_extra_logging                   | 0     |
          | ndb_force_send                      | ON    |
          | ndb_index_stat_cache_entries        | 32    |
          | ndb_index_stat_enable               | OFF   |
          | ndb_index_stat_update_freq          | 20    |
          | ndb_report_thresh_binlog_epoch_slip | 3     |
          | ndb_report_thresh_binlog_mem_usage  | 10    |
          | ndb_use_copying_alter_table         | OFF   |
          | ndb_use_exact_count                 | ON    |
          | ndb_use_transactions                | ON    |
          +-------------------------------------+-------+

     See *Note server-system-variables::, for more information.

   * `SHOW STATUS LIKE 'NDB%''

     This statement shows at a glance whether or not the MySQL server
     is acting as a cluster SQL node, and if so, it provides the MySQL
     server's cluster node ID, the host name and port for the cluster
     management server to which it is connected, and the number of data
     nodes in the cluster, as shown here:

          mysql> SHOW STATUS LIKE 'NDB%';
          +--------------------------+---------------+
          | Variable_name            | Value         |
          +--------------------------+---------------+
          | Ndb_cluster_node_id      | 10            |
          | Ndb_config_from_host     | 192.168.0.103 |
          | Ndb_config_from_port     | 1186          |
          | Ndb_number_of_data_nodes | 4             |
          +--------------------------+---------------+

     If the MySQL server was built with clustering support, but it is
     not connected to a cluster, all rows in the output of this
     statement contain a zero or an empty string:

          mysql> SHOW STATUS LIKE 'NDB%';
          +--------------------------+-------+
          | Variable_name            | Value |
          +--------------------------+-------+
          | Ndb_cluster_node_id      | 0     |
          | Ndb_config_from_host     |       |
          | Ndb_config_from_port     | 0     |
          | Ndb_number_of_data_nodes | 0     |
          +--------------------------+-------+

     See also *Note show-status::.


File: manual.info,  Node: mysql-cluster-security,  Prev: mysql-cluster-sql-statements,  Up: mysql-cluster-management

17.5.9 MySQL Cluster Security Issues
------------------------------------

* Menu:

* mysql-cluster-security-networking-issues::  MySQL Cluster Security and Networking Issues
* mysql-cluster-security-mysql-privileges::  MySQL Cluster and MySQL Privileges
* mysql-cluster-security-mysql-security-procedures::  MySQL Cluster and MySQL Security Procedures

This section discusses security considerations to take into account
when setting up and running MySQL Cluster.

Topics covered in this chapter include the following:

   * MySQL Cluster and network security issues

   * Configuration issues relating to running MySQL Cluster securely

   * MySQL Cluster and the MySQL privilege system

   * MySQL standard security procedures as applicable to MySQL Cluster


File: manual.info,  Node: mysql-cluster-security-networking-issues,  Next: mysql-cluster-security-mysql-privileges,  Prev: mysql-cluster-security,  Up: mysql-cluster-security

17.5.9.1 MySQL Cluster Security and Networking Issues
.....................................................

In this section, we discuss basic network security issues as they
relate to MySQL Cluster. It is extremely important to remember that
MySQL Cluster `out of the box' is not secure; you or your network
administrator must take the proper steps to ensure that your cluster
cannot be compromised over the network.

Cluster communication protocols are inherently insecure, and no
encryption or similar security measures are used in communications
between nodes in the cluster. Because network speed and latency have a
direct impact on the cluster's efficiency, it is also not advisable to
employ SSL or other encryption to network connections between nodes, as
such schemes will effectively slow communications.

It is also true that no authentication is used for controlling API node
access to a MySQL Cluster. As with encryption, the overhead of imposing
authentication requirements would have an adverse impact on Cluster
performance.

In addition, there is no checking of the source IP address for either
of the following when accessing the cluster:

   * SQL or API nodes using `free slots' created by empty `[mysqld]' or
     `[api]' sections in the `config.ini' file

     This means that, if there are any empty `[mysqld]' or `[api]'
     sections in the `config.ini' file, then any API nodes (including
     SQL nodes) that know the management server's host name (or IP
     address) and port can connect to the cluster and access its data
     without restriction. (See *Note
     mysql-cluster-security-mysql-privileges::, for more information
     about this and related issues.)

     *Note*:

     You can exercise some control over SQL and API node access to the
     cluster by specifying a `HostName' parameter for all `[mysqld]' and
     `[api]' sections in the `config.ini' file. However, this also
     means that, should you wish to connect an API node to the cluster
     from a previously unused host, you need to add an `[api]' section
     containing its host name to the `config.ini' file.

     More information is available elsewhere in this chapter about the
     `HostName' parameter. Also see *Note mysql-cluster-quick::, for
     configuration examples using `HostName' with API nodes.

   * Any *Note `ndb_mgm': mysql-cluster-programs-ndb-mgm. client

     This means that any cluster management client that is given the
     management server's host name (or IP address) and port (if not the
     standard port) can connect to the cluster and execute any
     management client command. This includes commands such as `ALL
     STOP' and `SHUTDOWN'.

For these reasons, it is necessary to protect the cluster on the
network level. The safest network configuration for Cluster is one
which isolates connections between Cluster nodes from any other network
communications. This can be accomplished by any of the following
methods:

  1. Keeping Cluster nodes on a network that is physically separate
     from any public networks. This option is the most dependable;
     however, it is the most expensive to implement.

     We show an example of a MySQL Cluster setup using such a
     physically segregated network here:

     MySQL Cluster on a private network protected with a hardware
     firewall

     This setup has two networks, one private (solid box) for the
     Cluster management servers and data nodes, and one public (dotted
     box) where the SQL nodes reside. (We show the management and data
     nodes connected using a gigabit switch since this provides the
     best performance.) Both networks are protected from the outside by
     a hardware firewall, sometimes also known as a _network-based
     firewall_.

     This network setup is safest because no packets can reach the
     cluster's management or data nodes from outside the network--and
     none of the cluster's internal communications can reach the
     outside--without going through the SQL nodes, as long as the SQL
     nodes do not permit any packets to be forwarded. This means, of
     course, that all SQL nodes must be secured against hacking
     attempts.

     *Important*:

     With regard to potential security vulnerabilities, an SQL node is
     no different from any other MySQL server. See *Note
     security-against-attack::, for a description of techniques you can
     use to secure MySQL servers.

  2. Using one or more software firewalls (also known as _host-based
     firewalls_) to control which packets pass through to the cluster
     from portions of the network that do not require access to it. In
     this type of setup, a software firewall must be installed on every
     host in the cluster which might otherwise be accessible from
     outside the local network.

     The host-based option is the least expensive to implement, but
     relies purely on software to provide protection and so is the most
     difficult to keep secure.

     This type of network setup for MySQL Cluster is illustrated here:

     MySQL Cluster deployed on a network using software firewalls to
     create public and private zones

     Using this type of network setup means that there are two zones of
     MySQL Cluster hosts. Each cluster host must be able to communicate
     with all of the other machines in the cluster, but only those
     hosting SQL nodes (dotted box) can be permitted to have any
     contact with the outside, while those in the zone containing the
     data nodes and management nodes (solid box) must be isolated from
     any machines that are not part of the cluster. Applications using
     the cluster and user of those applications must _not_ be permitted
     to have direct access to the management and data node hosts.

     To accomplish this, you must set up software firewalls that limit
     the traffic to the type or types shown in the following table,
     according to the type of node that is running on each cluster host
     computer:

     Type of Node to   Traffic to Permit
     be Accessed       
     SQL or API node      * It originates from the IP address of a
                            management or data node (using any TCP or UDP
                            port).
                       
                          * It originates from within the network in
                            which the cluster resides and is on the port
                            that your application is using.
     Data node or         * It originates from the IP address of a
     Management node        management or data node (using any TCP or UDP
                            port).
                       
                          * It originates from the IP address of an SQL
                            or API node.
     Any traffic other than that shown in the table for a given node
     type should be denied.

     The specifics of configuring a firewall vary from firewall
     application to firewall application, and are beyond the scope of
     this Manual. `iptables' is a very common and reliable firewall
     application, which is often used with `APF' as a front end to make
     configuration easier. You can (and should) consult the
     documentation for the software firewall that you employ, should
     you choose to implement a MySQL Cluster network setup of this
     type, or of a `mixed' type as discussed under the next item.

  3. It is also possible to employ a combination of the first two
     methods, using both hardware and software to secure the
     cluster--that is, using both network-based and host-based
     firewalls. This is between the first two schemes in terms of both
     security level and cost. This type of network setup keeps the
     cluster behind the hardware firewall, but permits incoming packets
     to travel beyond the router connecting all cluster hosts to reach
     the SQL nodes.

     One possible network deployment of a MySQL Cluster using hardware
     and software firewalls in combination is shown here:

     Network setup for MySQL Cluster using a combination of hardware
     and software firewalls to provide protection

     In this case, you can set the rules in the hardware firewall to
     deny any external traffic except to SQL nodes and API nodes, and
     then permit traffic to them only on the ports required by your
     application.

Whatever network configuration you use, remember that your objective
from the viewpoint of keeping the cluster secure remains the same--to
prevent any unessential traffic from reaching the cluster while
ensuring the most efficient communication between the nodes in the
cluster.

Because MySQL Cluster requires large numbers of ports to be open for
communications between nodes, the recommended option is to use a
segregated network. This represents the simplest way to prevent
unwanted traffic from reaching the cluster.

*Note*:

If you wish to administer a MySQL Cluster remotely (that is, from
outside the local network), the recommended way to do this is to use
`ssh' or another secure login shell to access an SQL node host. From
this host, you can then run the management client to access the
management server safely, from within the Cluster's own local network.

Even though it is possible to do so in theory, it is _not_ recommended
to use *Note `ndb_mgm': mysql-cluster-programs-ndb-mgm. to manage a
Cluster directly from outside the local network on which the Cluster is
running.  Since neither authentication nor encryption takes place
between the management client and the management server, this
represents an extremely insecure means of managing the cluster, and is
almost certain to be compromised sooner or later.


File: manual.info,  Node: mysql-cluster-security-mysql-privileges,  Next: mysql-cluster-security-mysql-security-procedures,  Prev: mysql-cluster-security-networking-issues,  Up: mysql-cluster-security

17.5.9.2 MySQL Cluster and MySQL Privileges
...........................................

In this section, we discuss how the MySQL privilege system works in
relation to MySQL Cluster and the implications of this for keeping a
MySQL Cluster secure.

Standard MySQL privileges apply to MySQL Cluster tables. This includes
all MySQL privilege types (`SELECT' privilege, `UPDATE' privilege,
`DELETE' privilege, and so on) granted on the database, table, and
column level. As with any other MySQL Server, user and privilege
information is stored in the `mysql' system database. The SQL statements
used to grant and revoke privileges on *Note `NDB': mysql-cluster.
tables, databases containing such tables, and columns within such
tables are identical in all respects with the *Note `GRANT': grant. and
*Note `REVOKE': revoke. statements used in connection with database
objects involving any (other) MySQL storage engine. The same thing is
true with respect to the *Note `CREATE USER': create-user. and *Note
`DROP USER': drop-user. statements.

It is important to keep in mind that the MySQL grant tables use the
`MyISAM' storage engine. Because of this, those tables are not
duplicated or shared among MySQL servers acting as SQL nodes in a MySQL
Cluster. By way of example, suppose that two SQL nodes *A* and *B* are
connected to the same MySQL Cluster, which has an *Note `NDB':
mysql-cluster.  table named `mytable' in a database named `mydb', and
that you execute an SQL statement on server *A* that creates a new user
`jon@localhost' and grants this user the `SELECT' privilege on that
table:

     mysql> GRANT SELECT ON mydb.mytable
         ->   TO jon@localhost IDENTIFIED BY 'mypass';

This user is _not_ created on server *B*. For this to take place, the
statement must also be run on server *B*. Similarly, statements run on
server *A* and affecting the privileges of existing users on server *A*
do not affect users on server *B* unless those statements are actually
run on server *B* as well.

In other words, _changes in users and their privileges do not
automatically propagate between SQL nodes_.  Synchronization of
privileges between SQL nodes must be done either manually or by
scripting an application that periodically synchronizes the privilege
tables on all SQL nodes in the cluster.

Conversely, because there is no way in MySQL to deny privileges
(privileges can either be revoked or not granted in the first place,
but not denied as such), there is no special protection for *Note
`NDB': mysql-cluster. tables on one SQL node from users that have
privileges on another SQL node. The most far-reaching example of this
is the MySQL `root' account, which can perform any action on any
database object. In combination with empty `[mysqld]' or `[api]'
sections of the `config.ini' file, this account can be especially
dangerous. To understand why, consider the following scenario:

   * The `config.ini' file contains at least one empty `[mysqld]' or
     `[api]' section. This means that the Cluster management server
     performs no checking of the host from which a MySQL Server (or
     other API node) accesses the MySQL Cluster.

   * There is no firewall, or the firewall fails to protect against
     access to the Cluster from hosts external to the network.

   * The host name or IP address of the Cluster's management server is
     known or can be determined from outside the network.

If these conditions are true, then anyone, anywhere can start a MySQL
Server with `--ndbcluster --ndb-connectstring=MANAGEMENT_HOST' and
access the Cluster. Using the MySQL `root' account, this person can
then perform the following actions:

   * Execute a *Note `SHOW DATABASES': show-databases.  statement to
     obtain a list of all databases that exist in the cluster

   * Execute a `SHOW TABLES FROM SOME_DATABASE' statement to obtain a
     list of all *Note `NDB': mysql-cluster.  tables in a given database

   * Run any legal MySQL statements on any of those tables, such as:

        * `SELECT * FROM SOME_TABLE' to read all the data from any table

        * `DELETE FROM SOME_TABLE' to delete all the data from a table

        * `DESCRIBE SOME_TABLE' or `SHOW CREATE TABLE SOME_TABLE' to
          determine the table schema

        * `UPDATE SOME_TABLE SET COLUMN1 = ANY_VALUE1' to fill a table
          column with `garbage' data; this could actually cause much
          greater damage than simply deleting all the data

          Even more insidious variations might include statements like
          these:

               UPDATE SOME_TABLE SET AN_INT_COLUMN = AN_INT_COLUMN + 1

          or

               UPDATE SOME_TABLE SET A_VARCHAR_COLUMN = REVERSE(A_VARCHAR_COLUMN)

          Such malicious statements are limited only by the imagination
          of the attacker.

     The only tables that would be safe from this sort of mayhem would
     be those tables that were created using storage engines other than
     *Note `NDB': mysql-cluster, and so not visible to a `rogue' SQL
     node.

     *Note*:

     A user who can log in as `root' can also access the
     `INFORMATION_SCHEMA' database and its tables, and so obtain
     information about databases, tables, stored routines, scheduled
     events, and any other database objects for which metadata is
     stored in `INFORMATION_SCHEMA'.

     It is also a very good idea to use different passwords for the
     `root' accounts on different cluster SQL nodes.

In sum, you cannot have a safe MySQL Cluster if it is directly
accessible from outside your local network.

*Important*:

_Never leave the MySQL root account password empty_. This is just as
true when running MySQL as a MySQL Cluster SQL node as it is when
running it as a standalone (non-Cluster) MySQL Server, and should be
done as part of the MySQL installation process before configuring the
MySQL Server as an SQL node in a MySQL Cluster.

You should never convert the system tables in the `mysql' database to
use the *Note `NDB': mysql-cluster. storage engine. There are a number
of reasons why you should not do this, but the most important reason is
this: _Many of the SQL statements that affect `mysql' tables storing
information about user privileges, stored routines, scheduled events,
and other database objects cease to function if these tables are
changed to use any storage engine other than `MyISAM'_. This is a
consequence of various MySQL Server internals which are not expected to
change in the foreseeable future.

If you need to synchronize `mysql' system tables between SQL nodes, you
can use standard MySQL replication to do so, or employ a script to copy
table entries between the MySQL servers.

Summary

The two most important points to remember regarding the MySQL privilege
system with regard to MySQL Cluster are:

  1. Users and privileges established on one SQL node do not
     automatically exist or take effect on other SQL nodes in the
     cluster.

     Conversely, removing a user or privilege on one SQL node in the
     cluster does not remove the user or privilege from any other SQL
     nodes.

  2. Once a MySQL user is granted privileges on an *Note `NDB':
     mysql-cluster. table from one SQL node in a MySQL Cluster, that
     user can `see' any data in that table regardless of the SQL node
     from which the data originated.


File: manual.info,  Node: mysql-cluster-security-mysql-security-procedures,  Prev: mysql-cluster-security-mysql-privileges,  Up: mysql-cluster-security

17.5.9.3 MySQL Cluster and MySQL Security Procedures
....................................................

In this section, we discuss MySQL standard security procedures as they
apply to running MySQL Cluster.

In general, any standard procedure for running MySQL securely also
applies to running a MySQL Server as part of a MySQL Cluster. First and
foremost, you should always run a MySQL Server as the `mysql' system
user; this is no different from running MySQL in a standard
(non-Cluster) environment. The `mysql' system account should be
uniquely and clearly defined. Fortunately, this is the default behavior
for a new MySQL installation. You can verify that the *Note `mysqld':
mysqld. process is running as the system user `mysql' by using the
system command such as the one shown here:

     shell> ps aux | grep mysql
     root     10467  0.0  0.1   3616  1380 pts/3    S    11:53   0:00 \
       /bin/sh ./mysqld_safe --ndbcluster --ndb-connectstring=localhost:1186
     mysql    10512  0.2  2.5  58528 26636 pts/3    Sl   11:53   0:00 \
       /usr/local/mysql/libexec/mysqld --basedir=/usr/local/mysql \
       --datadir=/usr/local/mysql/var --user=mysql --ndbcluster \
       --ndb-connectstring=localhost:1186 --pid-file=/usr/local/mysql/var/mothra.pid \
       --log-error=/usr/local/mysql/var/mothra.err
     jon      10579  0.0  0.0   2736   688 pts/0    S+   11:54   0:00 grep mysql

If the *Note `mysqld': mysqld. process is running as any other user
than `mysql', you should immediately shut it down and restart it as the
`mysql' user. If this user does not exist on the system, the `mysql'
user account should be created, and this user should be part of the
`mysql' user group; in this case, you should also make sure that the
MySQL `DataDir' on this system is owned by the `mysql' user, and that
the SQL node's `my.cnf' file includes `user=mysql' in the `[mysqld]'
section. Alternatively, you can start the server with `--user=mysql' on
the command line, but it is preferable to use the `my.cnf' option, since
you might forget to use the command-line option and so have *Note
`mysqld': mysqld. running as another user unintentionally. The *Note
`mysqld_safe': mysqld-safe. startup script forces MySQL to run as the
`mysql' user.

*Important*:

Never run *Note `mysqld': mysqld. as the system root user.  Doing so
means that potentially any file on the system can be read by MySQL, and
thus--should MySQL be compromised--by an attacker.

As mentioned in the previous section (see *Note
mysql-cluster-security-mysql-privileges::), you should always set a
root password for the MySQL Server as soon as you have it running. You
should also delete the anonymous user account that is installed by
default. You can accomplish these tasks using the following statements:

     shell> mysql -u root

     mysql> UPDATE mysql.user
         ->     SET Password=PASSWORD('SECURE_PASSWORD')
         ->     WHERE User='root';

     mysql> DELETE FROM mysql.user
         ->     WHERE User='';

     mysql> FLUSH PRIVILEGES;

Be very careful when executing the *Note `DELETE': delete. statement
not to omit the `WHERE' clause, or you risk deleting _all_ MySQL users.
Be sure to run the *Note `FLUSH PRIVILEGES': flush. statement as soon
as you have modified the `mysql.user' table, so that the changes take
immediate effect. Without *Note `FLUSH PRIVILEGES': flush, the changes
do not take effect until the next time that the server is restarted.

*Note*:

Many of the MySQL Cluster utilities such as *Note `ndb_show_tables':
mysql-cluster-programs-ndb-show-tables, *Note `ndb_desc':
mysql-cluster-programs-ndb-desc, and *Note `ndb_select_all':
mysql-cluster-programs-ndb-select-all. also work without authentication
and can reveal table names, schemas, and data.  By default these are
installed on Unix-style systems with the permissions `wxr-xr-x' (755),
which means they can be executed by any user that can access the
`mysql/bin' directory.

See *Note mysql-cluster-programs::, for more information about these
utilities.


File: manual.info,  Node: stored-programs-views,  Next: information-schema,  Prev: mysql-cluster,  Up: Top

18 Stored Programs and Views
****************************

* Menu:

* stored-programs-defining::     Defining Stored Programs
* stored-routines::              Using Stored Routines (Procedures and Functions)
* triggers::                     Using Triggers
* views::                        Using Views
* stored-programs-security::     Access Control for Stored Programs and Views
* stored-programs-logging::      Binary Logging of Stored Programs

This chapter discusses stored programs and views, which are database
objects defined in terms of SQL code that is stored on the server for
later execution.

Stored programs include these objects:

   * Stored routines, that is, stored procedures and functions. A
     stored procedure is invoked using the *Note `CALL': call.
     statement. A procedure does not have a return value but can modify
     its parameters for later inspection by the caller. It can also
     generate result sets to be returned to the client program. A
     stored function is used much like a built-in function. you invoke
     it in an expression and it returns a value during expression
     evaluation.

   * Triggers. A trigger is a named database object that is associated
     with a table and that is activated when a particular event occurs
     for the table, such as an insert or update.

Views are stored queries that when referenced produce a result set.  A
view acts as a virtual table.

This chapter describes how to use stored programs and views. The
following sections provide additional information about SQL syntax for
statements related to these objects:

   * For each object type, there are `CREATE', `ALTER', and `DROP'
     statements that control which objects exist and how they are
     defined. See *Note sql-syntax-data-definition::.

   * The *Note `CALL': call. statement is used to invoke stored
     procedures. See *Note call::.

   * Stored program definitions include a body that may use compound
     statements, loops, conditionals, and declared variables. See *Note
     sql-syntax-compound-statements::.


File: manual.info,  Node: stored-programs-defining,  Next: stored-routines,  Prev: stored-programs-views,  Up: stored-programs-views

18.1 Defining Stored Programs
=============================

Each stored program contains a body that consists of an SQL statement.
This statement may be a compound statement made up of several
statements separated by semicolon (`;') characters. For example, the
following stored procedure has a body made up of a *Note `BEGIN ...
END': begin-end. block that contains a *Note `SET': set-option.
statement and a *Note `REPEAT': repeat-statement.  loop that itself
contains another *Note `SET': set-option.  statement:

     CREATE PROCEDURE dorepeat(p1 INT)
     BEGIN
       SET @x = 0;
       REPEAT SET @x = @x + 1; UNTIL @x > p1 END REPEAT;
     END;

If you use the *Note `mysql': mysql. client program to define a stored
program that contains the semicolon characters within its definition, a
problem arises. By default, *Note `mysql': mysql.  itself recognizes
semicolon as a statement delimiter, so you must redefine the delimiter
temporarily to cause *Note `mysql': mysql. to pass the entire stored
program definition to the server.

To redefine the *Note `mysql': mysql. delimiter, use the `delimiter'
command. The following example shows how to do this for the
`dorepeat()' procedure just shown. The delimiter is changed to `//' to
enable the entire definition to be passed to the server as a single
statement, and then restored to `;' before invoking the procedure. This
enables the `;' delimiter used in the procedure body to be passed
through to the server rather than being interpreted by *Note `mysql':
mysql.  itself.

     mysql> delimiter //

     mysql> CREATE PROCEDURE dorepeat(p1 INT)
         -> BEGIN
         ->   SET @x = 0;
         ->   REPEAT SET @x = @x + 1; UNTIL @x > p1 END REPEAT;
         -> END
         -> //
     Query OK, 0 rows affected (0.00 sec)

     mysql> delimiter ;

     mysql> CALL dorepeat(1000);
     Query OK, 0 rows affected (0.00 sec)

     mysql> SELECT @x;
     +------+
     | @x   |
     +------+
     | 1001 |
     +------+
     1 row in set (0.00 sec)

You can redefine the delimiter to a string other than `//', and the
delimiter can consist of a single character or multiple characters. You
should avoid the use of the backslash (``\'') character because that is
the escape character for MySQL.

The following is an example of a function that takes a parameter,
performs an operation using an SQL function, and returns the result. In
this case, it is unnecessary to use `delimiter' because the function
definition contains no internal `;' statement delimiters:

     mysql> CREATE FUNCTION hello (s CHAR(20))
     mysql> RETURNS CHAR(50) DETERMINISTIC
         -> RETURN CONCAT('Hello, ',s,'!');
     Query OK, 0 rows affected (0.00 sec)

     mysql> SELECT hello('world');
     +----------------+
     | hello('world') |
     +----------------+
     | Hello, world!  |
     +----------------+
     1 row in set (0.00 sec)


File: manual.info,  Node: stored-routines,  Next: triggers,  Prev: stored-programs-defining,  Up: stored-programs-views

18.2 Using Stored Routines (Procedures and Functions)
=====================================================

* Menu:

* stored-routines-syntax::       Stored Routine Syntax
* stored-routines-privileges::   Stored Routines and MySQL Privileges
* stored-routines-metadata::     Stored Routine Metadata
* stored-routines-last-insert-id::  Stored Procedures, Functions, Triggers, and `LAST_INSERT_ID()'

Stored routines (procedures and functions) are supported in MySQL 5.0.
A stored routine is a set of SQL statements that can be stored in the
server. Once this has been done, clients don't need to keep reissuing
the individual statements but can refer to the stored routine instead.

Stored routines require the `proc' table in the `mysql' database. This
table is created during the MySQL 5.0 installation procedure. If you
are upgrading to MySQL 5.0 from an earlier version, be sure to update
your grant tables to make sure that the `proc' table exists. See *Note
mysql-upgrade::.

Stored routines can be particularly useful in certain situations:

   * When multiple client applications are written in different
     languages or work on different platforms, but need to perform the
     same database operations.

   * When security is paramount. Banks, for example, use stored
     procedures and functions for all common operations. This provides
     a consistent and secure environment, and routines can ensure that
     each operation is properly logged. In such a setup, applications
     and users would have no access to the database tables directly,
     but can only execute specific stored routines.

Stored routines can provide improved performance because less
information needs to be sent between the server and the client. The
tradeoff is that this does increase the load on the database server
because more of the work is done on the server side and less is done on
the client (application) side. Consider this if many client machines
(such as Web servers) are serviced by only one or a few database
servers.

Stored routines also enable you to have libraries of functions in the
database server. This is a feature shared by modern application
languages that enable such design internally (for example, by using
classes). Using these client application language features is
beneficial for the programmer even outside the scope of database use.

MySQL follows the SQL:2003 syntax for stored routines, which is also
used by IBM's DB2. All syntax described here is supported and any
limitations and extensions are documented where appropriate.

* Additional Resources *

   * You may find the Stored Procedures User Forum
     (http://forums.mysql.com/list.php?98) of use when working with
     stored procedures and functions.

   * For answers to some commonly asked questions regarding stored
     routines in MySQL, see *Note faqs-stored-procs::.

   * There are some restrictions on the use of stored routines. See
     *Note stored-program-restrictions::.

   * Binary logging for stored routines takes place as described in
     *Note stored-programs-logging::.


File: manual.info,  Node: stored-routines-syntax,  Next: stored-routines-privileges,  Prev: stored-routines,  Up: stored-routines

18.2.1 Stored Routine Syntax
----------------------------

A stored routine is either a procedure or a function. Stored routines
are created with the *Note `CREATE PROCEDURE': create-procedure. and
*Note `CREATE FUNCTION': create-function. statements (see *Note
create-procedure::). A procedure is invoked using a *Note `CALL': call.
statement (see *Note call::), and can only pass back values using
output variables. A function can be called from inside a statement just
like any other function (that is, by invoking the function's name), and
can return a scalar value. The body of a stored routine can use
compound statements (see *Note sql-syntax-compound-statements::).

Stored routines can be dropped with the *Note `DROP PROCEDURE':
drop-procedure. and *Note `DROP FUNCTION': drop-function. statements
(see *Note drop-procedure::), and altered with the *Note `ALTER
PROCEDURE': alter-procedure. and *Note `ALTER FUNCTION':
alter-function. statements (see *Note alter-procedure::).

As of MySQL 5.0.1, a stored procedure or function is associated with a
particular database. This has several implications:

   * When the routine is invoked, an implicit `USE DB_NAME' is
     performed (and undone when the routine terminates).  *Note `USE':
     use. statements within stored routines are not permitted.

   * You can qualify routine names with the database name. This can be
     used to refer to a routine that is not in the current database.
     For example, to invoke a stored procedure `p' or function `f' that
     is associated with the `test' database, you can say `CALL
     test.p()' or `test.f()'.

   * When a database is dropped, all stored routines associated with it
     are dropped as well.

(In MySQL 5.0.0, stored routines are global and not associated with a
database. They inherit the default database from the caller. If a `USE
DB_NAME' is executed within the routine, the original default database
is restored upon routine exit.)

Stored functions cannot be recursive.

Recursion in stored procedures is permitted but disabled by default. To
enable recursion, set the `max_sp_recursion_depth' server system
variable to a value greater than zero. Stored procedure recursion
increases the demand on thread stack space. If you increase the value of
`max_sp_recursion_depth', it may be necessary to increase thread stack
size by increasing the value of `thread_stack' at server startup.  See
*Note server-system-variables::, for more information.

MySQL supports a very useful extension that enables the use of regular
*Note `SELECT': select. statements (that is, without using cursors or
local variables) inside a stored procedure. The result set of such a
query is simply sent directly to the client. Multiple *Note `SELECT':
select.  statements generate multiple result sets, so the client must
use a MySQL client library that supports multiple result sets. This
means the client must use a client library from a version of MySQL at
least as recent as 4.1. The client should also specify the
`CLIENT_MULTI_RESULTS' option when it connects.  For C programs, this
can be done with the *Note `mysql_real_connect()': mysql-real-connect.
C API function. See *Note mysql-real-connect::, and *Note
c-api-multiple-queries::.


File: manual.info,  Node: stored-routines-privileges,  Next: stored-routines-metadata,  Prev: stored-routines-syntax,  Up: stored-routines

18.2.2 Stored Routines and MySQL Privileges
-------------------------------------------

Beginning with MySQL 5.0.3, the grant system takes stored routines into
account as follows:

   * The `CREATE ROUTINE' privilege is needed to create stored routines.

   * The `ALTER ROUTINE' privilege is needed to alter or drop stored
     routines. This privilege is granted automatically to the creator
     of a routine if necessary, and dropped from the creator when the
     routine is dropped.

   * The `EXECUTE' privilege is required to execute stored routines.
     However, this privilege is granted automatically to the creator of
     a routine if necessary (and dropped from the creator when the
     routine is dropped). Also, the default `SQL SECURITY'
     characteristic for a routine is `DEFINER', which enables users who
     have access to the database with which the routine is associated
     to execute the routine.

   * If the `automatic_sp_privileges' system variable is 0, the
     `EXECUTE' and `ALTER ROUTINE' privileges are not automatically
     granted to and dropped from the routine creator.

   * The creator of a routine is the account used to execute the
     `CREATE' statement for it. This might not be the same as the
     account named as the `DEFINER' in the routine definition.

The server manipulates the `mysql.proc' table in response to statements
that create, alter, or drop stored routines. It is not supported that
the server will notice manual manipulation of this table.


File: manual.info,  Node: stored-routines-metadata,  Next: stored-routines-last-insert-id,  Prev: stored-routines-privileges,  Up: stored-routines

18.2.3 Stored Routine Metadata
------------------------------

Metadata about stored routines can be obtained as follows:

   * Query the *Note `ROUTINES': routines-table. table of the
     `INFORMATION_SCHEMA' database. See *Note routines-table::.

   * Use the *Note `SHOW CREATE PROCEDURE': show-create-procedure.  and
     *Note `SHOW CREATE FUNCTION': show-create-function.  statements to
     see routine definitions. See *Note show-create-procedure::.

   * Use the *Note `SHOW PROCEDURE STATUS': show-procedure-status.  and
     *Note `SHOW FUNCTION STATUS': show-function-status.  statements to
     see routine characteristics. See *Note show-procedure-status::.

   * `INFORMATION_SCHEMA' does not have a `PARAMETERS' table until
     MySQL 5.5, so applications that need to acquire routine parameter
     information at runtime must use workarounds such as parsing the
     output of `SHOW CREATE' statements or the `param_list' column of
     the `mysql.proc' table.  `param_list' contents can be processed
     from within a stored routine, unlike the output from *Note `SHOW':
     show.


File: manual.info,  Node: stored-routines-last-insert-id,  Prev: stored-routines-metadata,  Up: stored-routines

18.2.4 Stored Procedures, Functions, Triggers, and `LAST_INSERT_ID()'
---------------------------------------------------------------------

Within the body of a stored routine (procedure or function) or a
trigger, the value of `LAST_INSERT_ID()' changes the same way as for
statements executed outside the body of these kinds of objects (see
*Note information-functions::). The effect of a stored routine or
trigger upon the value of `LAST_INSERT_ID()' that is seen by following
statements depends on the kind of routine:

   * If a stored procedure executes statements that change the value of
     `LAST_INSERT_ID()', the changed value is seen by statements that
     follow the procedure call.

   * For stored functions and triggers that change the value, the value
     is restored when the function or trigger ends, so following
     statements do not see a changed value. (Before MySQL 5.0.12, the
     value is not restored and following statements do see a changed
     value.)


File: manual.info,  Node: triggers,  Next: views,  Prev: stored-routines,  Up: stored-programs-views

18.3 Using Triggers
===================

* Menu:

* trigger-syntax::               Trigger Syntax
* trigger-metadata::             Trigger Metadata

Support for triggers is included beginning with MySQL 5.0.2. A trigger
is a named database object that is associated with a table, and that
activates when a particular event occurs for the table.  Some uses for
triggers are to perform checks of values to be inserted into a table or
to perform calculations on values involved in an update.

A trigger is defined to activate when an *Note `INSERT': insert, *Note
`DELETE': delete, or *Note `UPDATE': update. statement executes for the
associated table. A trigger can be set to activate either before or
after the triggering statement. For example, you can have a trigger
activate before each row that is inserted into a table or after each
row that is updated.

*Important*:

MySQL triggers are activated by SQL statements _only_. They are not
activated by changes in tables made by APIs that do not transmit SQL
statements to the MySQL Server; in particular, they are not activated
by updates made using the *Note `NDB': mysql-cluster. API.

To use triggers if you have upgraded to MySQL 5.0 from an older release
that did not support triggers, you should upgrade your grant tables so
that they contain the trigger-related privileges. See *Note
mysql-upgrade::.

The following discussion describes the syntax for creating and dropping
triggers, and shows some examples of how to use them.

* Additional Resources *

   * You may find the Triggers User Forum
     (http://forums.mysql.com/list.php?100) of use when working with
     views.

   * For answers to some commonly asked questions regarding triggers in
     MySQL, see *Note faqs-triggers::.

   * There are some restrictions on the use of triggers; see *Note
     stored-program-restrictions::.

   * Binary logging for triggers takes place as described in *Note
     stored-programs-logging::.


File: manual.info,  Node: trigger-syntax,  Next: trigger-metadata,  Prev: triggers,  Up: triggers

18.3.1 Trigger Syntax
---------------------

To create a trigger or drop a trigger, use the *Note `CREATE TRIGGER':
create-trigger. or *Note `DROP TRIGGER': drop-trigger. statement. The
syntax for these statements is described in *Note create-trigger::, and
*Note drop-trigger::.

Here is a simple example that associates a trigger with a table for
*Note `INSERT': insert. statements. The trigger acts as an accumulator,
summing the values inserted into one of the columns of the table.

     mysql> CREATE TABLE account (acct_num INT, amount DECIMAL(10,2));
     Query OK, 0 rows affected (0.03 sec)

     mysql> CREATE TRIGGER ins_sum BEFORE INSERT ON account
         -> FOR EACH ROW SET @sum = @sum + NEW.amount;
     Query OK, 0 rows affected (0.06 sec)

The *Note `CREATE TRIGGER': create-trigger. statement creates a trigger
named `ins_sum' that is associated with the `account' table. It also
includes clauses that specify the trigger activation time, the
triggering event, and what to do with the trigger activates:

   * The keyword `BEFORE' indicates the trigger action time. In this
     case, the trigger should activate before each row inserted into
     the table. The other permissible keyword here is `AFTER'.

   * The keyword *Note `INSERT': insert. indicates the event that
     activates the trigger. In the example, *Note `INSERT': insert.
     statements cause trigger activation. You can also create triggers
     for *Note `DELETE': delete. and *Note `UPDATE': update. statements.

   * The statement following `FOR EACH ROW' defines the statement to
     execute each time the trigger activates, which occurs once for
     each row affected by the triggering statement In the example, the
     triggered statement is a simple *Note `SET': set-option. that
     accumulates the values inserted into the `amount' column. The
     statement refers to the column as `NEW.amount' which means `the
     value of the `amount' column to be inserted into the new row.'

To use the trigger, set the accumulator variable to zero, execute an
*Note `INSERT': insert. statement, and then see what value the variable
has afterward:

     mysql> SET @sum = 0;
     mysql> INSERT INTO account VALUES(137,14.98),(141,1937.50),(97,-100.00);
     mysql> SELECT @sum AS 'Total amount inserted';
     +-----------------------+
     | Total amount inserted |
     +-----------------------+
     | 1852.48               |
     +-----------------------+

In this case, the value of `@sum' after the *Note `INSERT': insert.
statement has executed is `14.98 + 1937.50 - 100', or `1852.48'.

To destroy the trigger, use a *Note `DROP TRIGGER': drop-trigger.
statement. You must specify the schema name if the trigger is not in
the default schema:

     mysql> DROP TRIGGER test.ins_sum;

Triggers for a table are also dropped if you drop the table.

Trigger names exist in the schema namespace, meaning that all triggers
must have unique names within a schema. Triggers in different schemas
can have the same name.

In addition to the requirement that trigger names be unique for a
schema, there are other limitations on the types of triggers you can
create. In particular, you cannot have two triggers for a table that
have the same activation time and activation event. For example, you
cannot define two `BEFORE INSERT' triggers or two `AFTER UPDATE'
triggers for a table. This should rarely be a significant limitation,
because it is possible to define a trigger that executes multiple
statements by using the *Note `BEGIN ... END': begin-end. compound
statement construct after `FOR EACH ROW'. (An example appears later in
this section.)

The `OLD' and `NEW' keywords enable you to access columns in the rows
affected by a trigger.  (`OLD' and `NEW' are not case sensitive.) In an
`INSERT' trigger, only `NEW.COL_NAME' can be used; there is no old row.
In a `DELETE' trigger, only `OLD.COL_NAME' can be used; there is no new
row. In an `UPDATE' trigger, you can use `OLD.COL_NAME' to refer to the
columns of a row before it is updated and `NEW.COL_NAME' to refer to
the columns of the row after it is updated.

A column named with `OLD' is read only. You can refer to it (if you
have the *Note `SELECT': select.  privilege), but not modify it. A
column named with `NEW' can be referred to if you have the `SELECT'
privilege for it. In a `BEFORE' trigger, you can also change its value
with `SET NEW.COL_NAME = VALUE' if you have the `UPDATE' privilege for
it. This means you can use a trigger to modify the values to be
inserted into a new row or that are used to update a row.

In a `BEFORE' trigger, the `NEW' value for an `AUTO_INCREMENT' column
is 0, not the automatically generated sequence number that will be
generated when the new record actually is inserted.

`OLD' and `NEW' are MySQL extensions to triggers.

By using the *Note `BEGIN ... END': begin-end. construct, you can
define a trigger that executes multiple statements. Within the `BEGIN'
block, you also can use other syntax that is permitted within stored
routines such as conditionals and loops. However, just as for stored
routines, if you use the *Note `mysql': mysql. program to define a
trigger that executes multiple statements, it is necessary to redefine
the *Note `mysql': mysql. statement delimiter so that you can use the
`;' statement delimiter within the trigger definition. The following
example illustrates these points. It defines an `UPDATE' trigger that
checks the new value to be used for updating each row, and modifies the
value to be within the range from 0 to 100.  This must be a `BEFORE'
trigger because the value needs to be checked before it is used to
update the row:

     mysql> delimiter //
     mysql> CREATE TRIGGER upd_check BEFORE UPDATE ON account
         -> FOR EACH ROW
         -> BEGIN
         ->     IF NEW.amount < 0 THEN
         ->         SET NEW.amount = 0;
         ->     ELSEIF NEW.amount > 100 THEN
         ->         SET NEW.amount = 100;
         ->     END IF;
         -> END;//
     mysql> delimiter ;

It can be easier to define a stored procedure separately and then
invoke it from the trigger using a simple *Note `CALL': call.
statement. This is also advantageous if you want to invoke the same
routine from within several triggers.

There are some limitations on what can appear in statements that a
trigger executes when activated:

   * The trigger cannot use the *Note `CALL': call.  statement to
     invoke stored procedures that return data to the client or that
     use dynamic SQL. (Stored procedures are permitted to return data
     to the trigger through `OUT' or `INOUT' parameters.)

   * The trigger cannot use statements that explicitly or implicitly
     begin or end a transaction such as *Note `START TRANSACTION':
     commit, *Note `COMMIT': commit, or *Note `ROLLBACK': commit.

   * Prior to MySQL 5.0.10, triggers cannot contain direct references
     to tables by name.

MySQL handles errors during trigger execution as follows:

   * If a `BEFORE' trigger fails, the operation on the corresponding
     row is not performed.

   * A `BEFORE' trigger is activated by the _attempt_ to insert or
     modify the row, regardless of whether the attempt subsequently
     succeeds.

   * An `AFTER' trigger is executed only if the `BEFORE' trigger (if
     any) and the row operation both execute successfully.

   * An error during either a `BEFORE' or `AFTER' trigger results in
     failure of the entire statement that caused trigger invocation.

   * For transactional tables, failure of a statement should cause
     rollback of all changes performed by the statement. Failure of a
     trigger causes the statement to fail, so trigger failure also
     causes rollback. For nontransactional tables, such rollback cannot
     be done, so although the statement fails, any changes performed
     prior to the point of the error remain in effect.


File: manual.info,  Node: trigger-metadata,  Prev: trigger-syntax,  Up: triggers

18.3.2 Trigger Metadata
-----------------------

Metadata about triggers can be obtained as follows:

   * Query the *Note `TRIGGERS': triggers-table. table of the
     `INFORMATION_SCHEMA' database. See *Note triggers-table::.

   * Use the *Note `SHOW TRIGGERS': show-triggers.  statement. See
     *Note show-triggers::.


File: manual.info,  Node: views,  Next: stored-programs-security,  Prev: triggers,  Up: stored-programs-views

18.4 Using Views
================

* Menu:

* view-syntax::                  View Syntax
* view-algorithms::              View Processing Algorithms
* view-updatability::            Updatable and Insertable Views
* view-metadata::                View Metadata

Views (including updatable views) are available in MySQL Server 5.0.
Views are stored queries that when invoked produce a result set. A view
acts as a virtual table. Views are available in binary releases from
5.0.1 and up.

To use views if you have upgraded to MySQL 5.0.1 from an older release,
you should upgrade your grant tables so that they contain the
view-related privileges. See *Note mysql-upgrade::.

The following discussion describes the syntax for creating and dropping
views, and shows some examples of how to use them.

* Additional Resources *

   * You may find the Views User Forum
     (http://forums.mysql.com/list.php?100) of use when working with
     views.

   * For answers to some commonly asked questions regarding views in
     MySQL, see *Note faqs-views::.

   * There are some restrictions on the use of views; see *Note
     view-restrictions::.


File: manual.info,  Node: view-syntax,  Next: view-algorithms,  Prev: views,  Up: views

18.4.1 View Syntax
------------------

The *Note `CREATE VIEW': create-view. statement creates a new view (see
*Note create-view::). To alter the definition of a view or drop a view,
use *Note `ALTER VIEW': alter-view. (see *Note alter-view::), or *Note
`DROP VIEW': drop-view. (see *Note drop-view::).

A view can be created from many kinds of *Note `SELECT': select.
statements. It can refer to base tables or other views. It can use
joins, *Note `UNION': union, and subqueries. The *Note `SELECT':
select. need not even refer to any tables. The following example
defines a view that selects two columns from another table, as well as
an expression calculated from those columns:

     mysql> CREATE TABLE t (qty INT, price INT);
     mysql> INSERT INTO t VALUES(3, 50), (5, 60);
     mysql> CREATE VIEW v AS SELECT qty, price, qty*price AS value FROM t;
     mysql> SELECT * FROM v;
     +------+-------+-------+
     | qty  | price | value |
     +------+-------+-------+
     |    3 |    50 |   150 |
     |    5 |    60 |   300 |
     +------+-------+-------+
     mysql> SELECT * FROM v WHERE qty = 5;
     +------+-------+-------+
     | qty  | price | value |
     +------+-------+-------+
     |    5 |    60 |   300 |
     +------+-------+-------+


File: manual.info,  Node: view-algorithms,  Next: view-updatability,  Prev: view-syntax,  Up: views

18.4.2 View Processing Algorithms
---------------------------------

The optional `ALGORITHM' clause for *Note `CREATE VIEW': create-view. or
*Note `ALTER VIEW': alter-view. is a MySQL extension to standard SQL.
It affects how MySQL processes the view.  `ALGORITHM' takes three
values: `MERGE', `TEMPTABLE', or `UNDEFINED'. The default algorithm is
`UNDEFINED' if no `ALGORITHM' clause is present.

For `MERGE', the text of a statement that refers to the view and the
view definition are merged such that parts of the view definition
replace corresponding parts of the statement.

For `TEMPTABLE', the results from the view are retrieved into a
temporary table, which then is used to execute the statement.

For `UNDEFINED', MySQL chooses which algorithm to use. It prefers
`MERGE' over `TEMPTABLE' if possible, because `MERGE' is usually more
efficient and because a view cannot be updatable if a temporary table
is used.

A reason to choose `TEMPTABLE' explicitly is that locks can be released
on underlying tables after the temporary table has been created and
before it is used to finish processing the statement. This might result
in quicker lock release than the `MERGE' algorithm so that other
clients that use the view are not blocked as long.

A view algorithm can be `UNDEFINED' for three reasons:

   * No `ALGORITHM' clause is present in the *Note `CREATE VIEW':
     create-view. statement.

   * The *Note `CREATE VIEW': create-view. statement has an explicit
     `ALGORITHM = UNDEFINED' clause.

   * `ALGORITHM = MERGE' is specified for a view that can be processed
     only with a temporary table. In this case, MySQL generates a
     warning and sets the algorithm to `UNDEFINED'.

As mentioned earlier, `MERGE' is handled by merging corresponding parts
of a view definition into the statement that refers to the view. The
following examples briefly illustrate how the `MERGE' algorithm works.
The examples assume that there is a view `v_merge' that has this
definition:

     CREATE ALGORITHM = MERGE VIEW v_merge (vc1, vc2) AS
     SELECT c1, c2 FROM t WHERE c3 > 100;

Example 1: Suppose that we issue this statement:

     SELECT * FROM v_merge;

MySQL handles the statement as follows:

   * `v_merge' becomes `t'

   * `*' becomes `vc1, vc2', which corresponds to `c1, c2'

   * The view `WHERE' clause is added

The resulting statement to be executed becomes:

     SELECT c1, c2 FROM t WHERE c3 > 100;

Example 2: Suppose that we issue this statement:

     SELECT * FROM v_merge WHERE vc1 < 100;

This statement is handled similarly to the previous one, except that
`vc1 < 100' becomes `c1 < 100' and the view `WHERE' clause is added to
the statement `WHERE' clause using an `AND' connective (and parentheses
are added to make sure the parts of the clause are executed with
correct precedence). The resulting statement to be executed becomes:

     SELECT c1, c2 FROM t WHERE (c3 > 100) AND (c1 < 100);

Effectively, the statement to be executed has a `WHERE' clause of this
form:

     WHERE (select WHERE) AND (view WHERE)

If the `MERGE' algorithm cannot be used, a temporary table must be used
instead. `MERGE' cannot be used if the view contains any of the
following constructs:

   * Aggregate functions (`SUM()', `MIN()', `MAX()', `COUNT()', and so
     forth)

   * `DISTINCT'

   * `GROUP BY'

   * `HAVING'

   * `LIMIT'

   * *Note `UNION': union. or *Note `UNION ALL': union.

   * Subquery in the select list

   * Refers only to literal values (in this case, there is no
     underlying table)


File: manual.info,  Node: view-updatability,  Next: view-metadata,  Prev: view-algorithms,  Up: views

18.4.3 Updatable and Insertable Views
-------------------------------------

Some views are updatable. That is, you can use them in statements such
as *Note `UPDATE': update, *Note `DELETE': delete, or *Note `INSERT':
insert. to update the contents of the underlying table. For a view to
be updatable, there must be a one-to-one relationship between the rows
in the view and the rows in the underlying table. There are also
certain other constructs that make a view nonupdatable. To be more
specific, a view is not updatable if it contains any of the following:

   * Aggregate functions (`SUM()', `MIN()', `MAX()', `COUNT()', and so
     forth)

   * `DISTINCT'

   * `GROUP BY'

   * `HAVING'

   * *Note `UNION': union. or *Note `UNION ALL': union.

   * Subquery in the select list

   * Certain joins (see additional join discussion later in this
     section)

   * Nonupdatable view in the `FROM' clause

   * A subquery in the `WHERE' clause that refers to a table in the
     `FROM' clause

   * Refers only to literal values (in this case, there is no
     underlying table to update)

   * Uses `ALGORITHM = TEMPTABLE' (use of a temporary table always
     makes a view nonupdatable)

   * Multiple references to any column of a base table.

With respect to insertability (being updatable with *Note `INSERT':
insert. statements), an updatable view is insertable if it also
satisfies these additional requirements for the view columns:

   * There must be no duplicate view column names.

   * The view must contain all columns in the base table that do not
     have a default value.

   * The view columns must be simple column references and not derived
     columns. A derived column is one that is not a simple column
     reference but is derived from an expression. These are examples of
     derived columns:

          3.14159
          col1 + 3
          UPPER(col2)
          col3 / col4
          (SUBQUERY)

A view that has a mix of simple column references and derived columns
is not insertable, but it can be updatable if you update only those
columns that are not derived. Consider this view:

     CREATE VIEW v AS SELECT col1, 1 AS col2 FROM t;

This view is not insertable because `col2' is derived from an
expression. But it is updatable if the update does not try to update
`col2'. This update is permissible:

     UPDATE v SET col1 = 0;

This update is not permissible because it attempts to update a derived
column:

     UPDATE v SET col2 = 0;

It is sometimes possible for a multiple-table view to be updatable,
assuming that it can be processed with the `MERGE' algorithm. For this
to work, the view must use an inner join (not an outer join or a *Note
`UNION': union.). Also, only a single table in the view definition can
be updated, so the `SET' clause must name only columns from one of the
tables in the view. Views that use *Note `UNION ALL': union. are not
permitted even though they might be theoretically updatable, because
the implementation uses temporary tables to process them.

For a multiple-table updatable view, *Note `INSERT': insert. can work
if it inserts into a single table. *Note `DELETE': delete. is not
supported.

*Note `INSERT DELAYED': insert-delayed. is not supported for views.

If a table contains an `AUTO_INCREMENT' column, inserting into an
insertable view on the table that does not include the `AUTO_INCREMENT'
column does not change the value of `LAST_INSERT_ID()', because the side
effects of inserting default values into columns not part of the view
should not be visible.

The `WITH CHECK OPTION' clause can be given for an updatable view to
prevent inserts or updates to rows except those for which the `WHERE'
clause in the SELECT_STATEMENT is true.

In a `WITH CHECK OPTION' clause for an updatable view, the `LOCAL' and
`CASCADED' keywords determine the scope of check testing when the view
is defined in terms of another view. The `LOCAL' keyword restricts the
`CHECK OPTION' only to the view being defined. `CASCADED' causes the
checks for underlying views to be evaluated as well. When neither
keyword is given, the default is `CASCADED'. Consider the definitions
for the following table and set of views:

     mysql> CREATE TABLE t1 (a INT);
     mysql> CREATE VIEW v1 AS SELECT * FROM t1 WHERE a < 2
         -> WITH CHECK OPTION;
     mysql> CREATE VIEW v2 AS SELECT * FROM v1 WHERE a > 0
         -> WITH LOCAL CHECK OPTION;
     mysql> CREATE VIEW v3 AS SELECT * FROM v1 WHERE a > 0
         -> WITH CASCADED CHECK OPTION;

Here the `v2' and `v3' views are defined in terms of another view, `v1'.
`v2' has a `LOCAL' check option, so inserts are tested only against the
`v2' check. `v3' has a `CASCADED' check option, so inserts are tested
not only against its own check, but against those of underlying views.
The following statements illustrate these differences:

     mysql> INSERT INTO v2 VALUES (2);
     Query OK, 1 row affected (0.00 sec)
     mysql> INSERT INTO v3 VALUES (2);
     ERROR 1369 (HY000): CHECK OPTION failed 'test.v3'

MySQL sets a flag, called the view updatability flag, at *Note `CREATE
VIEW': create-view. time. The flag is set to `YES' (true) if *Note
`UPDATE': update. and *Note `DELETE': delete. (and similar operations)
are legal for the view. Otherwise, the flag is set to `NO' (false). The
`IS_UPDATABLE' column in the *Note `INFORMATION_SCHEMA.VIEWS':
views-table. table displays the status of this flag. It means that the
server always knows whether a view is updatable. If the view is not
updatable, statements such *Note `UPDATE': update, *Note `DELETE':
delete, and *Note `INSERT': insert. are illegal and will be rejected.
(Note that even if a view is updatable, it might not be possible to
insert into it, as described elsewhere in this section.)

The updatability of views may be affected by the value of the
`updatable_views_with_limit' system variable. See *Note
server-system-variables::.


File: manual.info,  Node: view-metadata,  Prev: view-updatability,  Up: views

18.4.4 View Metadata
--------------------

Metadata about views can be obtained as follows:

   * Query the *Note `VIEWS': views-table. table of the
     `INFORMATION_SCHEMA' database. See *Note views-table::.

   * Use the *Note `SHOW CREATE VIEW': show-create-view.  statement.
     See *Note show-create-view::.


File: manual.info,  Node: stored-programs-security,  Next: stored-programs-logging,  Prev: views,  Up: stored-programs-views

18.5 Access Control for Stored Programs and Views
=================================================

Stored programs and views are defined prior to use and, when
referenced, execute within a security context that determines their
privileges. These privileges are controlled by their `DEFINER'
attribute, and, if there is one, their `SQL SECURITY' characteristic.

All stored programs (procedures, functions, and triggers) and views can
have a `DEFINER' attribute that names a MySQL account. If the `DEFINER'
attribute is omitted from a stored program or view definition, the
default account is the user who creates the object.

In addition, stored routines (procedures and functions) and views can
have a `SQL SECURITY' characteristic with a value of `DEFINER' or
`INVOKER' to specify whether the object executes in definer or invoker
context. If the `SQL SECURITY' characteristic is omitted, the default
is definer context.

Triggers have no `SQL SECURITY' characteristic and always execute in
definer context. The server invokes these objects automatically as
necessary, so there is no invoking user.

Definer and invoker security contexts differ as follows:

   * A stored program or view that executes in definer security context
     executes with the privileges of the account named by its `DEFINER'
     attribute. These privileges may be entirely different from those
     of the invoking user. The invoker must have appropriate privileges
     to reference the object (for example, `EXECUTE' to call a stored
     procedure or `SELECT' to select from a view), but when the object
     executes, the invoker's privileges are ignored and only the
     `DEFINER' account privileges matter. If this account has few
     privileges, the object is correspondingly limited in the
     operations it can perform. If the `DEFINER' account is highly
     privileged (such as a `root' account), the object can perform
     powerful operations _no matter who invokes it._

   * A stored routine or view that executes in invoker security context
     can perform only operations for which the invoker has privileges.
     The `DEFINER' attribute can be specified but has no effect for
     objects that execute in invoker context.

Consider the following stored procedure:

     CREATE DEFINER = 'admin'@'localhost' PROCEDURE p1()
     SQL SECURITY DEFINER
     BEGIN
       UPDATE t1 SET counter = counter + 1;
     END;

Any user who has the `EXECUTE' privilege for `p1' can invoke it with a
*Note `CALL': call. statement. However, when `p1' executes, it does so
in `DEFINER' security context and thus executes with the privileges of
`'admin'@'localhost'', the account named in the `DEFINER' attribute.
This account must have the `EXECUTE' privilege for `p1' as well as the
`UPDATE' privilege for the table `t1'. Otherwise, the procedure fails.

Now consider this stored procedure, which is identical to `p1' except
that its `SQL SECURITY' characteristic is `INVOKER':

     CREATE DEFINER = 'admin'@'localhost' PROCEDURE p2()
     SQL SECURITY INVOKER
     BEGIN
       UPDATE t1 SET counter = counter + 1;
     END;

`p2', unlike `p1', executes in `INVOKER' security context. The
`DEFINER' attribute is irrelevant and `p2' executes with the privileges
of the invoking user. `p2' fails if the invoker lacks the `EXECUTE'
privilege for `p2' or the `UPDATE' privilege for the table `t1'.

MySQL uses the following rules to control which accounts a user can
specify in an object `DEFINER' attribute:

   * You can specify a `DEFINER' value other than your own account only
     if you have the `SUPER' privilege.

   * If you do not have the `SUPER' privilege, the only legal user
     value is your own account, either specified literally or by using
     `CURRENT_USER'. You cannot set the definer to some other account.

To minimize the risk potential for stored program and view creation and
use, follow these guidelines:

   * For a stored routine or view, use `SQL SECURITY INVOKER' in the
     object definition when possible so that it can be used only by
     users with permissions appropriate for the operations performed by
     the object.

   * If you create definer-context stored programs or views while using
     an account that has the `SUPER' privilege, specify an explicit
     `DEFINER' attribute that names an account possessing only the
     privileges required for the operations performed by the object.
     Specify a highly privileged `DEFINER' account only when absolutely
     necessary.

   * Administrators can prevent users from specifying highly privileged
     `DEFINER' accounts by not granting them the `SUPER' privilege.

   * Definer-context objects should be written keeping in mind that
     they may be able to access data for which the invoking user has no
     privileges. In some cases, you can prevent reference to these
     objects by not granting unauthorized users particular privileges:

        * A stored procedure or function cannot be referenced by a user
          who does not have the `EXECUTE' privilege for it.

        * A view cannot be referenced by a user who does not have the
          appropriate privilege for it (`SELECT' to select from it,
          `INSERT' to insert into it, and so forth).

     However, no such control exists for triggers because users do not
     reference them directly. A trigger always executes in `DEFINER'
     context and is activated by access to the table with which it is
     associated, even ordinary table accesses by users with no special
     privileges. If the `DEFINER' account is highly privileged, the
     trigger can perform sensitive or dangerous operations. This
     remains true if the `SUPER' privilege needed to create the trigger
     is revoked from the account of the user who created it.
     Administrators should be especially careful about granting users
     that privilege.


File: manual.info,  Node: stored-programs-logging,  Prev: stored-programs-security,  Up: stored-programs-views

18.6 Binary Logging of Stored Programs
======================================

The binary log contains information about SQL statements that modify
database contents. This information is stored in the form of `events'
that describe the modifications. The binary log has two important
purposes:

   * For replication, the binary log is used on master replication
     servers as a record of the statements to be sent to slave servers.
     The master server sends the events contained in its binary log to
     its slaves, which execute those events to make the same data
     changes that were made on the master. See *Note
     replication-implementation::.

   * Certain data recovery operations require use of the binary log.
     After a backup file has been restored, the events in the binary
     log that were recorded after the backup was made are re-executed.
     These events bring databases up to date from the point of the
     backup. See *Note recovery-from-backups::.

However, there are certain binary logging issues that apply with
respect to stored programs (stored procedures and functions, and
triggers):

   * Logging occurs at the statement level. In some cases, it is
     possible that a statement will affect different sets of rows on a
     master and a slave.

   * Replicated statements executed on a slave are processed by the
     slave SQL thread, which has full privileges. It is possible for a
     procedure to follow different execution paths on master and slave
     servers, so a user can write a routine containing a dangerous
     statement that will execute only on the slave where it is
     processed by a thread that has full privileges.

   * If a stored program that modifies data is nondeterministic, it is
     not repeatable. This can result in different data on a master and
     slave, or cause restored data to differ from the original data.

This section describes how MySQL 5.0 handles binary logging for stored
programs. The discussion first states the current conditions that the
implementation places on the use of stored programs, and what you can
do to avoid problems. Then it summarizes the changes that have taken
place in the logging implementation. Finally, implementation details
are given that provide information about when and why various changes
were made.  These details show how several aspects of the current
logging behavior were implemented in response to shortcomings identified
in earlier versions of MySQL.

In general, the issues described here occur due to the fact that binary
logging occurs at the SQL statement level. MySQL 5.1 implements
row-level binary logging, which solves or alleviates these issues
because the log contains changes made to individual rows as a result of
executing SQL statements.

Unless noted otherwise, the remarks here assume that you have enabled
binary logging by starting the server with the `--log-bin' option. (See
*Note binary-log::.) If the binary log is not enabled, replication is
not possible, nor is the binary log available for data recovery.

The current conditions on the use of stored functions in MySQL 5.0 can
be summarized as follows. These conditions do not apply to stored
procedures and they do not apply unless binary logging is enabled.

   * To create or alter a stored function, you must have the `SUPER'
     privilege, in addition to the `CREATE ROUTINE' or `ALTER ROUTINE'
     privilege that is normally required. (Depending on the `DEFINER'
     value in the function definition, `SUPER' might be required
     regardless of whether binary logging is enabled. See *Note
     create-procedure::.)

   * When you create a stored function, you must declare either that it
     is deterministic or that it does not modify data.  Otherwise, it
     may be unsafe for data recovery or replication.

     By default, for a *Note `CREATE FUNCTION': create-function.
     statement to be accepted, at least one of `DETERMINISTIC', `NO
     SQL', or `READS SQL DATA' must be specified explicitly. Otherwise
     an error occurs:

          ERROR 1418 (HY000): This function has none of DETERMINISTIC, NO SQL,
          or READS SQL DATA in its declaration and binary logging is enabled
          (you *might* want to use the less safe log_bin_trust_function_creators
          variable)

     This function is deterministic (and does not modify data), so it
     is safe:

          CREATE FUNCTION f1(i INT)
          RETURNS INT
          DETERMINISTIC
          READS SQL DATA
          BEGIN
            RETURN i;
          END;

     This function uses `UUID()', which is not deterministic, so the
     function also is not deterministic and is not safe:

          CREATE FUNCTION f2()
          RETURNS CHAR(36) CHARACTER SET utf8
          BEGIN
            RETURN UUID();
          END;

     This function modifies data, so it may not be safe:

          CREATE FUNCTION f3(p_id INT)
          RETURNS INT
          BEGIN
            UPDATE t SET modtime = NOW() WHERE id = p_id;
            RETURN ROW_COUNT();
          END;

     Assessment of the nature of a function is based on the `honesty'
     of the creator: MySQL does not check that a function declared
     `DETERMINISTIC' is free of statements that produce
     nondeterministic results.

   * To relax the preceding conditions on function creation (that you
     must have the `SUPER' privilege and that a function must be
     declared deterministic or to not modify data), set the global
     `log_bin_trust_function_creators' system variable to 1. By
     default, this variable has a value of 0, but you can change it
     like this:

          mysql> SET GLOBAL log_bin_trust_function_creators = 1;

     You can also set this variable by using the
     `--log-bin-trust-function-creators=1' option when starting the
     server.

     If binary logging is not enabled, `log_bin_trust_function_creators'
     does not apply. `SUPER' is not required for function creation
     unless, as described previously, the `DEFINER' value in the
     function definition requires it.

   * For information about built-in functions that may be unsafe for
     replication (and thus cause stored functions that use them to be
     unsafe as well), see *Note replication-features::.

Triggers are similar to stored functions, so the preceding remarks
regarding functions also apply to triggers with the following
exception: *Note `CREATE TRIGGER': create-trigger. does not have an
optional `DETERMINISTIC' characteristic, so triggers are assumed to be
always deterministic. However, this assumption might in some cases be
invalid. For example, the `UUID()' function is nondeterministic (and
does not replicate). You should be careful about using such functions
in triggers.

Triggers can update tables, so error messages similar to those for
stored functions occur with *Note `CREATE TRIGGER': create-trigger. if
you do not have the required privileges. On the slave side, the slave
uses the trigger `DEFINER' attribute to determine which user is
considered to be the creator of the trigger.

The rest of this section provides details on the development of stored
routine logging. You need not read it unless you are interested in the
background on the rationale for the current logging-related conditions
on stored routine use.

The development of stored routine logging in MySQL 5.0 can be
summarized as follows:

   * Before MySQL 5.0.6: In the initial implementation of stored
     routine logging, statements that create stored routines and *Note
     `CALL': call. statements are not logged.  These omissions can
     cause problems for replication and data recovery.

   * MySQL 5.0.6: Statements that create stored routines and *Note
     `CALL': call. statements are logged.  Stored function invocations
     are logged when they occur in statements that update data (because
     those statements are logged). However, function invocations are
     not logged when they occur in statements such as *Note `SELECT':
     select. that do not change data, even if a data change occurs
     within a function itself; this can cause problems. Under some
     circumstances, functions and procedures can have different effects
     if executed at different times or on different (master and slave)
     machines, and thus can be unsafe for data recovery or replication.
     To handle this, measures are implemented to enable identification
     of safe routines and to prevent creation of unsafe routines except
     by users with sufficient privileges.

   * MySQL 5.0.12: For stored functions, when a function invocation
     that changes data occurs within a nonlogged statement such as
     *Note `SELECT': select, the server logs a `DO FUNC_NAME()'
     statement that invokes the function so that the function gets
     executed during data recovery or replication to slave servers.
     For stored procedures, the server does not log *Note `CALL': call.
     statements. Instead, it logs individual statements within a
     procedure that are executed as a result of a *Note `CALL': call.
     This eliminates problems that may occur when a procedure would
     follow a different execution path on a slave than on the master.

   * MySQL 5.0.16: The procedure logging changes made in 5.0.12 enable
     the conditions on unsafe routines to be relaxed for stored
     procedures. Consequently, the user interface for controlling these
     conditions is revised to apply only to functions. Procedure
     creators are no longer bound by them.

   * MySQL 5.0.17: Logging of stored functions as `DO FUNC_NAME()'
     statements (per the changes made in 5.0.12) are logged as `SELECT
     FUNC_NAME()' statements instead for better control over error
     checking.

*Routine logging before MySQL 5.0.6:* Statements that create and use
stored routines are not written to the binary log, but statements
invoked within stored routines are logged. Suppose that you issue the
following statements:

     CREATE PROCEDURE mysp INSERT INTO t VALUES(1);
     CALL mysp();

For this example, only the *Note `INSERT': insert.  statement appears
in the binary log. The *Note `CREATE PROCEDURE': create-procedure. and
*Note `CALL': call. statements do not appear. The absence of
routine-related statements in the binary log means that stored routines
are not replicated correctly. It also means that for a data recovery
operation, re-executing events in the binary log does not recover
stored routines.

*Routine logging changes in MySQL 5.0.6:* To address the absence of
logging for stored routine creation and *Note `CALL': call.  statements
(and the consequent replication and data recovery concerns), the
characteristics of binary logging for stored routines were changed as
described here. (Some of the items in the following list point out
issues that are dealt with in later versions.)

   * The server writes *Note `CREATE PROCEDURE': create-procedure,
     *Note `CREATE FUNCTION': create-function, *Note `ALTER PROCEDURE':
     alter-procedure, *Note `ALTER FUNCTION': alter-function, *Note
     `DROP PROCEDURE': drop-procedure, and *Note `DROP FUNCTION':
     drop-function. statements to the binary log. Also, the server logs
     *Note `CALL': call. statements, not the statements executed within
     procedures. Suppose that you issue the following statements:

          CREATE PROCEDURE mysp INSERT INTO t VALUES(1);
          CALL mysp();

     For this example, the *Note `CREATE PROCEDURE': create-procedure.
     and *Note `CALL': call.  statements appear in the binary log, but
     the *Note `INSERT': insert. statement does not appear. This
     corrects the problem that occurred before MySQL 5.0.6 such that
     only the *Note `INSERT': insert.  was logged.

   * Logging *Note `CALL': call. statements has a security implication
     for replication, which arises from two factors:

        * Statements executed on a slave are processed by the slave SQL
          thread which has full privileges.

        * It is possible for a procedure to follow different execution
          paths on master and slave servers.

     The implication is that although a user must have the `CREATE
     ROUTINE' privilege to create a routine, the user can write a
     routine containing a dangerous statement that will execute only on
     the slave where it is processed by a thread that has full
     privileges. For example, if the master and slave servers have
     server ID values of 1 and 2, respectively, a user on the master
     server could create and invoke an unsafe procedure `unsafe_sp()'
     as follows:

          mysql> delimiter //
          mysql> CREATE PROCEDURE unsafe_sp ()
              -> BEGIN
              ->   IF @@server_id=2 THEN DROP DATABASE accounting; END IF;
              -> END;
              -> //
          mysql> delimiter ;
          mysql> CALL unsafe_sp();

     The *Note `CREATE PROCEDURE': create-procedure. and *Note `CALL':
     call. statements are written to the binary log, so the slave will
     execute them. Because the slave SQL thread has full privileges, it
     will execute the *Note `DROP DATABASE': drop-database. statement
     that drops the `accounting' database. Thus, the *Note `CALL':
     call. statement has different effects on the master and slave and
     is not replication-safe.

     The preceding example uses a stored procedure, but similar
     problems can occur for stored functions that are invoked within
     statements that are written to the binary log: Function invocation
     has different effects on the master and slave.

     To guard against this danger for servers that have binary logging
     enabled, MySQL 5.0.6 introduces the requirement that stored
     procedure and function creators must have the `SUPER' privilege,
     in addition to the usual `CREATE ROUTINE' privilege that is
     required. Similarly, to use *Note `ALTER PROCEDURE':
     alter-procedure. or *Note `ALTER FUNCTION': alter-function, you
     must have the `SUPER' privilege in addition to the `ALTER ROUTINE'
     privilege.  Without the `SUPER' privilege, an error will occur:

          ERROR 1419 (HY000): You do not have the SUPER privilege and
          binary logging is enabled (you *might* want to use the less safe
          log_bin_trust_routine_creators variable)

     If you do not want to require routine creators to have the `SUPER'
     privilege (for example, if all users with the `CREATE ROUTINE'
     privilege on your system are experienced application developers),
     set the global `log_bin_trust_routine_creators' system variable to
     1. You can also set this variable by using the
     `--log-bin-trust-routine-creators=1' option when starting the
     server. If binary logging is not enabled,
     `log_bin_trust_routine_creators' does not apply. `SUPER' is not
     required for routine creation unless, as described previously, the
     `DEFINER' value in the routine definition requires it.

   * If a routine that performs updates is nondeterministic, it is not
     repeatable. This can have two undesirable effects:

        * It will make a slave different from the master.

        * Restored data will be different from the original data.

     To deal with these problems, MySQL enforces the following
     requirement: On a master server, creation and alteration of a
     routine is refused unless you declare the routine to be
     deterministic or to not modify data. Two sets of routine
     characteristics apply here:

        * The `DETERMINISTIC' and `NOT DETERMINISTIC' characteristics
          indicate whether a routine always produces the same result
          for given inputs.  The default is `NOT DETERMINISTIC' if
          neither characteristic is given. To declare that a routine is
          deterministic, you must specify `DETERMINISTIC' explicitly.

        * The `CONTAINS SQL', `NO SQL', `READS SQL DATA', and `MODIFIES
          SQL DATA' characteristics provide information about whether
          the routine reads or writes data. Either `NO SQL' or `READS
          SQL DATA' indicates that a routine does not change data, but
          you must specify one of these explicitly because the default
          is `CONTAINS SQL' if no characteristic is given.

     By default, for a *Note `CREATE PROCEDURE': create-procedure. or
     *Note `CREATE FUNCTION': create-function. statement to be
     accepted, at least one of `DETERMINISTIC', `NO SQL', or `READS SQL
     DATA' must be specified explicitly. Otherwise an error occurs:

          ERROR 1418 (HY000): This routine has none of DETERMINISTIC, NO SQL,
          or READS SQL DATA in its declaration and binary logging is enabled
          (you *might* want to use the less safe log_bin_trust_routine_creators
          variable)

     If you set `log_bin_trust_routine_creators' to 1, the requirement
     that routines be deterministic or not modify data is dropped.

   * A *Note `CALL': call. statement is written to the binary log if
     the routine returns no error, but not otherwise. When a routine
     that modifies data fails, you get this warning:

          ERROR 1417 (HY000): A routine failed and has neither NO SQL nor
          READS SQL DATA in its declaration and binary logging is enabled; if
          non-transactional tables were updated, the binary log will miss their
          changes

     This logging behavior has the potential to cause problems. If a
     routine partly modifies a nontransactional table (such as a
     `MyISAM' table) and returns an error, the binary log will not
     reflect these changes. To protect against this, you should use
     transactional tables in the routine and modify the tables within
     transactions.

     If you use the `IGNORE' keyword with *Note `INSERT': insert, *Note
     `DELETE': delete, or *Note `UPDATE': update. to ignore errors
     within a routine, a partial update might occur but no error will
     result. Such statements are logged and they replicate normally.

   * Although statements normally are not written to the binary log if
     they are rolled back, *Note `CALL': call.  statements are logged
     even when they occur within a rolled-back transaction. This can
     result in a *Note `CALL': call. being rolled back on the master
     but executed on slaves.

   * If a stored function is invoked within a statement such as *Note
     `SELECT': select. that does not modify data, execution of the
     function is not written to the binary log, even if the function
     itself modifies data. This logging behavior has the potential to
     cause problems. Suppose that a function `myfunc()' is defined as
     follows:

          CREATE FUNCTION myfunc () RETURNS INT DETERMINISTIC
          BEGIN
            INSERT INTO t (i) VALUES(1);
            RETURN 0;
          END;

     Given that definition, the following statement is not written to
     the binary log because it is a *Note `SELECT': select.
     Nevertheless, it modifies the table `t' because `myfunc()'
     modifies `t':

          SELECT myfunc();

     A workaround for this problem is to invoke functions that do
     updates only within statements that do updates (and which
     therefore are written to the binary log). Note that although the
     *Note `DO': do. statement sometimes is executed for the side
     effect of evaluating an expression, *Note `DO': do. is not a
     workaround here because it is not written to the binary log.

   * On slave servers, `--replicate-*-table' rules do not apply to
     *Note `CALL': call. statements or to statements within stored
     routines. These statements are always replicated. If such
     statements contain references to tables that do not exist on the
     slave, they could have undesirable effects when executed on the
     slave.

*Routine logging changes in MySQL 5.0.12:* The changes in 5.0.12
address several problems that were present in earlier versions:

   * Stored function invocations in nonlogged statements such as *Note
     `SELECT': select. were not being logged, even when a function
     itself changed data.

   * Stored procedure logging at the *Note `CALL': call. level could
     cause different effects on a master and slave if a procedure took
     different execution paths on the two machines.

   * *Note `CALL': call. statements were logged even when they occurred
     within a rolled-back transaction.

To deal with these issues, MySQL 5.0.12 implements the following
changes to procedure and function logging:

   * A stored function invocation is logged as a *Note `DO': do.
     statement if the function changes data and occurs within a
     statement that would not otherwise be logged. This corrects the
     problem of nonreplication of data changes that result from use of
     stored functions in nonlogged statements. For example, *Note
     `SELECT': select. statements are not written to the binary log,
     but a *Note `SELECT': select. might invoke a stored function that
     makes changes. To handle this, a `DO FUNC_NAME()' statement is
     written to the binary log when the given function makes a change.
     Suppose that the following statements are executed on the master:

          CREATE FUNCTION f1(a INT) RETURNS INT
          BEGIN
            IF (a < 3) THEN
              INSERT INTO t2 VALUES (a);
            END IF;
            RETURN 0;
          END;

          CREATE TABLE t1 (a INT);
          INSERT INTO t1 VALUES (1),(2),(3);

          SELECT f1(a) FROM t1;

     When the *Note `SELECT': select. statement executes, the function
     `f1()' is invoked three times. Two of those invocations insert a
     row, and MySQL logs a *Note `DO': do. statement for each of them.
     That is, MySQL writes the following statements to the binary log:

          DO f1(1);
          DO f1(2);

     The server also logs a *Note `DO': do.  statement for a stored
     function invocation when the function invokes a stored procedure
     that causes an error. In this case, the server writes the *Note
     `DO': do.  statement to the log along with the expected error
     code. On the slave, if the same error occurs, that is the expected
     result and replication continues. Otherwise, replication stops.

     Note: See later in this section for changes made in MySQL 5.0.19:
     These logged `DO FUNC_NAME()' statements are logged as `SELECT
     FUNC_NAME()' statements instead.

   * Stored procedure calls are logged at the statement level rather
     than at the *Note `CALL': call. level.  That is, the server does
     not log the *Note `CALL': call. statement, it logs those
     statements within the procedure that actually execute. As a
     result, the same changes that occur on the master will be observed
     on slave servers. This eliminates the problems that could result
     from a procedure having different execution paths on different
     machines. For example, the *Note `DROP DATABASE': drop-database.
     problem shown earlier for the `unsafe_sp()' procedure does not
     occur and the routine is no longer replication-unsafe because it
     has the same effect on master and slave servers.

     In general, statements executed within a stored procedure are
     written to the binary log using the same rules that would apply
     were the statements to be executed in standalone fashion. Some
     special care is taken when logging procedure statements because
     statement execution within procedures is not quite the same as in
     nonprocedure context:

        * A statement to be logged might contain references to local
          procedure variables. These variables do not exist outside of
          stored procedure context, so a statement that refers to such
          a variable cannot be logged literally. Instead, each
          reference to a local variable is replaced by this construct
          for logging purposes:

               NAME_CONST(VAR_NAME, VAR_VALUE)

          VAR_NAME is the local variable name, and VAR_VALUE is a
          constant indicating the value that the variable has at the
          time the statement is logged.  `NAME_CONST()' has a value of
          VAR_VALUE, and a `name' of VAR_NAME. Thus, if you invoke this
          function directly, you get a result like this:

               mysql> SELECT NAME_CONST('myname', 14);
               +--------+
               | myname |
               +--------+
               |     14 |
               +--------+

          `NAME_CONST()' enables a logged standalone statement to be
          executed on a slave with the same effect as the original
          statement that was executed on the master within a stored
          procedure.

          The use of `NAME_CONST()' can result in a problem for *Note
          `CREATE TABLE ... SELECT': create-table. statements when the
          source column expressions refer to local variables.
          Converting these references to `NAME_CONST()' expressions can
          result in column names that are different on the master and
          slave servers, or names that are too long to be legal column
          identifiers. A workaround is to supply aliases for columns
          that refer to local variables.  Consider this statement when
          `myvar' has a value of 1:

               CREATE TABLE t1 SELECT myvar;

          That will be rewritten as follows:

               CREATE TABLE t1 SELECT NAME_CONST(myvar, 1);

          To ensure that the master and slave tables have the same
          column names, write the statement like this:

               CREATE TABLE t1 SELECT myvar AS myvar;

          The rewritten statement becomes:

               CREATE TABLE t1 SELECT NAME_CONST(myvar, 1) AS myvar;

        * A statement to be logged might contain references to
          user-defined variables. To handle this, MySQL writes a *Note
          `SET': set-option.  statement to the binary log to make sure
          that the variable exists on the slave with the same value as
          on the master.  For example, if a statement refers to a
          variable `@my_var', that statement will be preceded in the
          binary log by the following statement, where VALUE is the
          value of `@my_var' on the master:

               SET @my_var = VALUE;

        * Procedure calls can occur within a committed or rolled-back
          transaction. Previously, *Note `CALL': call. statements were
          logged even if they occurred within a rolled-back
          transaction. As of MySQL 5.0.12, transactional context is
          accounted for so that the transactional aspects of procedure
          execution are replicated correctly. That is, the server logs
          those statements within the procedure that actually execute
          and modify data, and also logs *Note `BEGIN': commit, *Note
          `COMMIT': commit, and *Note `ROLLBACK': commit.  statements
          as necessary. For example, if a procedure updates only
          transactional tables and is executed within a transaction
          that is rolled back, those updates are not logged. If the
          procedure occurs within a committed transaction, *Note
          `BEGIN': commit.  and *Note `COMMIT': commit. statements are
          logged with the updates. For a procedure that executes within
          a rolled-back transaction, its statements are logged using
          the same rules that would apply if the statements were
          executed in standalone fashion:

             * Updates to transactional tables are not logged.

             * Updates to nontransactional tables are logged because
               rollback does not cancel them.

             * Updates to a mix of transactional and nontransactional
               tables are logged surrounded by *Note `BEGIN': commit.
               and *Note `ROLLBACK': commit.  so that slaves will make
               the same changes and rollbacks as on the master.

   * A stored procedure call is _not_ written to the binary log at the
     statement level if the procedure is invoked from within a stored
     function. In that case, the only thing logged is the statement
     that invokes the function (if it occurs within a statement that is
     logged) or a *Note `DO': do. statement (if it occurs within a
     statement that is not logged). For this reason, care still should
     be exercised in the use of stored functions that invoke a
     procedure, even if the procedure is otherwise safe in itself.

   * Because procedure logging occurs at the statement level rather
     than at the *Note `CALL': call. level, interpretation of the
     `--replicate-*-table' options is revised to apply only to stored
     functions. They no longer apply to stored procedures, except those
     procedures that are invoked from within functions.

*Routine logging changes in MySQL 5.0.16:* In 5.0.12, a change was
introduced to log stored procedure calls at the statement level rather
than at the *Note `CALL': call. level. This change eliminates the
requirement that procedures be identified as safe. The requirement now
exists only for stored functions, because they still appear in the
binary log as function invocations rather than as the statements
executed within the function. To reflect the lifting of the restriction
on stored procedures, the `log_bin_trust_routine_creators' system
variable is renamed to `log_bin_trust_function_creators' and the
`--log-bin-trust-routine-creators' server option is renamed to
`--log-bin-trust-function-creators'.  (For backward compatibility, the
old names are recognized but result in a warning.) Error messages that
now apply only to functions and not to routines in general are
re-worded.

*Routine logging changes in MySQL 5.0.19:* In 5.0.12, a change was
introduced to log a stored function invocation as `DO FUNC_NAME()' if
the invocation changes data and occurs within a nonlogged statement, or
if the function invokes a stored procedure that produces an error. In
5.0.19, these invocations are logged as `SELECT FUNC_NAME()' instead.
The change to *Note `SELECT': select. was made because use of *Note
`DO': do. was found to yield insufficient control over error code
checking.


File: manual.info,  Node: information-schema,  Next: connectors-apis,  Prev: stored-programs-views,  Up: Top

19 `INFORMATION_SCHEMA' Tables
******************************

* Menu:

* character-sets-table::         The `INFORMATION_SCHEMA CHARACTER_SETS' Table
* collations-table::             The `INFORMATION_SCHEMA COLLATIONS' Table
* collation-character-set-applicability-table::  The `INFORMATION_SCHEMA COLLATION_CHARACTER_SET_APPLICABILITY' Table
* columns-table::                The `INFORMATION_SCHEMA COLUMNS' Table
* column-privileges-table::      The `INFORMATION_SCHEMA COLUMN_PRIVILEGES' Table
* key-column-usage-table::       The `INFORMATION_SCHEMA KEY_COLUMN_USAGE' Table
* profiling-table::              The `INFORMATION_SCHEMA PROFILING' Table
* routines-table::               The `INFORMATION_SCHEMA ROUTINES' Table
* schemata-table::               The `INFORMATION_SCHEMA SCHEMATA' Table
* schema-privileges-table::      The `INFORMATION_SCHEMA SCHEMA_PRIVILEGES' Table
* statistics-table::             The `INFORMATION_SCHEMA STATISTICS' Table
* tables-table::                 The `INFORMATION_SCHEMA TABLES' Table
* table-constraints-table::      The `INFORMATION_SCHEMA TABLE_CONSTRAINTS' Table
* table-privileges-table::       The `INFORMATION_SCHEMA TABLE_PRIVILEGES' Table
* triggers-table::               The `INFORMATION_SCHEMA TRIGGERS' Table
* user-privileges-table::        The `INFORMATION_SCHEMA USER_PRIVILEGES' Table
* views-table::                  The `INFORMATION_SCHEMA VIEWS' Table
* other-information-schema-tables::  Other `INFORMATION_SCHEMA' Tables
* extended-show::                Extensions to `SHOW' Statements

`INFORMATION_SCHEMA' provides access to database metadata.

_Metadata_ is data about the data, such as the name of a database or
table, the data type of a column, or access privileges. Other terms
that sometimes are used for this information are _data dictionary_ and
_system catalog_.

`INFORMATION_SCHEMA' is the information database, the place that stores
information about all the other databases that the MySQL server
maintains. Inside `INFORMATION_SCHEMA' there are several read-only
tables. They are actually views, not base tables, so there are no files
associated with them, and you cannot set triggers on them.  Also, there
is no database directory with that name.

Although you can select `INFORMATION_SCHEMA' as the default database
with a *Note `USE': use.  statement, you can only read the contents of
tables, not perform *Note `INSERT': insert, *Note `UPDATE': update, or
*Note `DELETE': delete. operations on them.

Here is an example of a statement that retrieves information from
`INFORMATION_SCHEMA':

     mysql> SELECT table_name, table_type, engine
         -> FROM information_schema.tables
         -> WHERE table_schema = 'db5'
         -> ORDER BY table_name DESC;
     +------------+------------+--------+
     | table_name | table_type | engine |
     +------------+------------+--------+
     | v56        | VIEW       | NULL   |
     | v3         | VIEW       | NULL   |
     | v2         | VIEW       | NULL   |
     | v          | VIEW       | NULL   |
     | tables     | BASE TABLE | MyISAM |
     | t7         | BASE TABLE | MyISAM |
     | t3         | BASE TABLE | MyISAM |
     | t2         | BASE TABLE | MyISAM |
     | t          | BASE TABLE | MyISAM |
     | pk         | BASE TABLE | InnoDB |
     | loop       | BASE TABLE | MyISAM |
     | kurs       | BASE TABLE | MyISAM |
     | k          | BASE TABLE | MyISAM |
     | into       | BASE TABLE | MyISAM |
     | goto       | BASE TABLE | MyISAM |
     | fk2        | BASE TABLE | InnoDB |
     | fk         | BASE TABLE | InnoDB |
     +------------+------------+--------+
     17 rows in set (0.01 sec)

Explanation: The statement requests a list of all the tables in
database `db5', in reverse alphabetic order, showing just three pieces
of information: the name of the table, its type, and its storage engine.

The definition for character columns (for example, `TABLES.TABLE_NAME')
is generally `VARCHAR(N) CHARACTER SET utf8' where N is at least 64.
MySQL uses the default collation for this character set
(`utf8_general_ci') for all searches, sorts, comparisons, and other
string operations on such columns. Values such as table names in
`INFORMATION_SCHEMA' columns are treated as strings, not identifiers,
and are not compared using the identifier rules described in *Note
identifier-case-sensitivity::. If the result of a string operation on
an `INFORMATION_SCHEMA' column differs from expectations, a workaround
is to use an explicit `COLLATE' clause to force a suitable collation
(*Note charset-collate::). You can also use the `UPPER()' or `LOWER()'
function. For example, in a `WHERE' clause, you might use:

     WHERE TABLE_NAME COLLATE utf8_bin = 'City'
     WHERE TABLE_NAME COLLATE utf8_general_ci = 'city'
     WHERE UPPER(TABLE_NAME) = 'CITY'
     WHERE LOWER(TABLE_NAME) = 'city'

Each MySQL user has the right to access these tables, but can see only
the rows in the tables that correspond to objects for which the user
has the proper access privileges. In some cases (for example, the
`ROUTINE_DEFINITION' column in the *Note `INFORMATION_SCHEMA.ROUTINES':
routines-table. table), users who have insufficient privileges will see
`NULL'.

The `SELECT ... FROM INFORMATION_SCHEMA' statement is intended as a
more consistent way to provide access to the information provided by
the various *Note `SHOW': show. statements that MySQL supports (*Note
`SHOW DATABASES': show-databases, *Note `SHOW TABLES': show-tables, and
so forth). Using *Note `SELECT': select. has these advantages, compared
to *Note `SHOW': show.:

   * It conforms to Codd's rules. That is, all access is done on tables.

   * Nobody needs to learn a new statement syntax. Because they already
     know how *Note `SELECT': select. works, they only need to learn
     the object names.

   * The implementor need not worry about adding keywords.

   * There are millions of possible output variations, instead of just
     one. This provides more flexibility for applications that have
     varying requirements about what metadata they need.

   * Migration is easier because every other DBMS does it this way.

However, because *Note `SHOW': show. is popular and because it might be
confusing were it to disappear, the advantages of conventional syntax
are not a sufficient reason to eliminate *Note `SHOW': show. In fact,
along with the implementation of `INFORMATION_SCHEMA', there are
enhancements to *Note `SHOW': show. as well. These are described in
*Note extended-show::.

There is no difference between the privileges required for *Note
`SHOW': show. statements and those required to select information from
`INFORMATION_SCHEMA'. In either case, you have to have some privilege
on an object in order to see information about it.

The implementation for the `INFORMATION_SCHEMA' table structures in
MySQL follows the ANSI/ISO SQL:2003 standard Part 11 `Schemata'. Our
intent is approximate compliance with SQL:2003 core feature F021 `Basic
information schema'.

Users of SQL Server 2000 (which also follows the standard) may notice a
strong similarity. However, MySQL has omitted many columns that are not
relevant for our implementation, and added columns that are
MySQL-specific. One such column is the `ENGINE' column in the *Note
`INFORMATION_SCHEMA.TABLES': tables-table.  table.

Although other DBMSs use a variety of names, like `syscat' or `system',
the standard name is `INFORMATION_SCHEMA'.

The following sections describe each of the tables and columns that are
in `INFORMATION_SCHEMA'. For each column, there are three pieces of
information:

   * ``INFORMATION_SCHEMA' Name' indicates the name for the column in
     the `INFORMATION_SCHEMA' table. This corresponds to the standard
     SQL name unless the `Remarks' field says `MySQL extension.'

   * `*Note `SHOW': show. Name' indicates the equivalent field name in
     the closest *Note `SHOW': show. statement, if there is one.

   * `Remarks' provides additional information where applicable. If
     this field is `NULL', it means that the value of the column is
     always `NULL'.  If this field says `MySQL extension,' the column is
     a MySQL extension to standard SQL.

To avoid using any name that is reserved in the standard or in DB2, SQL
Server, or Oracle, we changed the names of some columns marked `MySQL
extension'. (For example, we changed `COLLATION' to `TABLE_COLLATION'
in the *Note `TABLES': tables-table. table.) See the list of reserved
words near the end of this article:
`http://web.archive.org/web/20070409075643rn_1/www.dbazine.com/db2/db2-disarticles/gulutzan5'.

Many sections indicate what *Note `SHOW': show.  statement is
equivalent to a *Note `SELECT': select.  that retrieves information from
`INFORMATION_SCHEMA'. For *Note `SHOW': show. statements that display
information for the default database if you omit a `FROM DB_NAME'
clause, you can often select information for the default database by
adding an `AND TABLE_SCHEMA = DATABASE()' condition to the `WHERE'
clause of a query that retrieves information from an
`INFORMATION_SCHEMA' table.

For answers to questions that are often asked concerning the
`INFORMATION_SCHEMA' database, see *Note faqs-information-schema::.


File: manual.info,  Node: character-sets-table,  Next: collations-table,  Prev: information-schema,  Up: information-schema

19.1 The `INFORMATION_SCHEMA CHARACTER_SETS' Table
==================================================

The *Note `CHARACTER_SETS': character-sets-table. table provides
information about available character sets.

`INFORMATION_SCHEMA' Name     *Note `SHOW': show.    Remarks
                              Name                   
`CHARACTER_SET_NAME'          `Charset'              
`DEFAULT_COLLATE_NAME'        `Default collation'    
`DESCRIPTION'                 `Description'          MySQL extension
`MAXLEN'                      `Maxlen'               MySQL extension

The following statements are equivalent:

     SELECT * FROM INFORMATION_SCHEMA.CHARACTER_SETS
       [WHERE CHARACTER_SET_NAME LIKE 'WILD']

     SHOW CHARACTER SET
       [LIKE 'WILD']


File: manual.info,  Node: collations-table,  Next: collation-character-set-applicability-table,  Prev: character-sets-table,  Up: information-schema

19.2 The `INFORMATION_SCHEMA COLLATIONS' Table
==============================================

The *Note `COLLATIONS': collations-table. table provides information
about collations for each character set.

`INFORMATION_SCHEMA' Name     *Note `SHOW': show.    Remarks
                              Name                   
`COLLATION_NAME'              `Collation'            
`CHARACTER_SET_NAME'          `Charset'              MySQL extension
`ID'                          `Id'                   MySQL extension
`IS_DEFAULT'                  `Default'              MySQL extension
`IS_COMPILED'                 `Compiled'             MySQL extension
`SORTLEN'                     `Sortlen'              MySQL extension

   * `COLLATION_NAME' is the collation name.

   * `CHARACTER_SET_NAME' is the name of the character set with which
     the collation is associated.

   * `ID' is the collation ID.

   * `IS_DEFAULT' indicates whether the collation is the default for
     its character set.

   * `IS_COMPILED' indicates whether the character set is compiled into
     the server.

   * `SORTLEN' is related to the amount of memory required to sort
     strings expressed in the character set.

Collation information is also available from the *Note `SHOW
COLLATION': show-collation. statement. The following statements are
equivalent:

     SELECT COLLATION_NAME FROM INFORMATION_SCHEMA.COLLATIONS
       [WHERE COLLATION_NAME LIKE 'WILD']

     SHOW COLLATION
       [LIKE 'WILD']


File: manual.info,  Node: collation-character-set-applicability-table,  Next: columns-table,  Prev: collations-table,  Up: information-schema

19.3 The `INFORMATION_SCHEMA COLLATION_CHARACTER_SET_APPLICABILITY' Table
=========================================================================

The *Note `COLLATION_CHARACTER_SET_APPLICABILITY':
collation-character-set-applicability-table.  table indicates what
character set is applicable for what collation. The columns are
equivalent to the first two display fields that we get from *Note `SHOW
COLLATION': show-collation.

`INFORMATION_SCHEMA' Name     *Note `SHOW': show.    Remarks
                              Name                   
`COLLATION_NAME'              `Collation'            
`CHARACTER_SET_NAME'          `Charset'              


File: manual.info,  Node: columns-table,  Next: column-privileges-table,  Prev: collation-character-set-applicability-table,  Up: information-schema

19.4 The `INFORMATION_SCHEMA COLUMNS' Table
===========================================

The *Note `COLUMNS': columns-table. table provides information about
columns in tables.

`INFORMATION_SCHEMA' Name     *Note `SHOW': show.    Remarks
                              Name                   
`TABLE_CATALOG'                                      `NULL'
`TABLE_SCHEMA'                                       
`TABLE_NAME'                                         
`COLUMN_NAME'                 `Field'                
`ORDINAL_POSITION'                                   see notes
`COLUMN_DEFAULT'              `Default'              
`IS_NULLABLE'                 `Null'                 
`DATA_TYPE'                   `Type'                 
`CHARACTER_MAXIMUM_LENGTH'    `Type'                 
`CHARACTER_OCTET_LENGTH'                             
`NUMERIC_PRECISION'           `Type'                 
`NUMERIC_SCALE'               `Type'                 
`CHARACTER_SET_NAME'                                 
`COLLATION_NAME'              `Collation'            
`COLUMN_TYPE'                 `Type'                 MySQL extension
`COLUMN_KEY'                  `Key'                  MySQL extension
`EXTRA'                       `Extra'                MySQL extension
`PRIVILEGES'                  `Privileges'           MySQL extension
`COLUMN_COMMENT'              `Comment'              MySQL extension

*Notes*:

   * In *Note `SHOW': show, the `Type' display includes values from
     several different *Note `COLUMNS': columns-table. columns.

   * `ORDINAL_POSITION' is necessary because you might want to say
     `ORDER BY ORDINAL_POSITION'. Unlike *Note `SHOW': show, *Note
     `SELECT': select. does not have automatic ordering.

   * `CHARACTER_OCTET_LENGTH' should be the same as
     `CHARACTER_MAXIMUM_LENGTH', except for multi-byte character sets.

   * `CHARACTER_SET_NAME' can be derived from `Collation'. For example,
     if you say `SHOW FULL COLUMNS FROM t', and you see in the
     `Collation' column a value of `latin1_swedish_ci', the character
     set is what is before the first underscore: `latin1'.

The following statements are nearly equivalent:

     SELECT COLUMN_NAME, DATA_TYPE, IS_NULLABLE, COLUMN_DEFAULT
       FROM INFORMATION_SCHEMA.COLUMNS
       WHERE table_name = 'TBL_NAME'
       [AND table_schema = 'DB_NAME']
       [AND column_name LIKE 'WILD']

     SHOW COLUMNS
       FROM TBL_NAME
       [FROM DB_NAME]
       [LIKE 'WILD']


File: manual.info,  Node: column-privileges-table,  Next: key-column-usage-table,  Prev: columns-table,  Up: information-schema

19.5 The `INFORMATION_SCHEMA COLUMN_PRIVILEGES' Table
=====================================================

The *Note `COLUMN_PRIVILEGES': column-privileges-table. table provides
information about column privileges. This information comes from the
`mysql.columns_priv' grant table.

`INFORMATION_SCHEMA' Name     *Note `SHOW': show.    Remarks
                              Name                   
`GRANTEE'                                            `'USER_NAME'@'HOST_NAME''
                                                     value
`TABLE_CATALOG'                                      `NULL'
`TABLE_SCHEMA'                                       
`TABLE_NAME'                                         
`COLUMN_NAME'                                        
`PRIVILEGE_TYPE'                                     
`IS_GRANTABLE'                                       

*Notes*:

   * In the output from *Note `SHOW FULL COLUMNS': show-columns, the
     privileges are all in one field and in lowercase, for example,
     `select,insert,update,references'. In *Note `COLUMN_PRIVILEGES':
     column-privileges-table, there is one privilege per row, in
     uppercase.

   * `PRIVILEGE_TYPE' can contain one (and only one) of these values:
     `SELECT', `INSERT', `UPDATE', `REFERENCES'.

   * If the user has `GRANT OPTION' privilege, `IS_GRANTABLE' should be
     `YES'. Otherwise, `IS_GRANTABLE' should be `NO'. The output does
     not list `GRANT OPTION' as a separate privilege.

The following statements are _not_ equivalent:

     SELECT ... FROM INFORMATION_SCHEMA.COLUMN_PRIVILEGES

     SHOW GRANTS ...


File: manual.info,  Node: key-column-usage-table,  Next: profiling-table,  Prev: column-privileges-table,  Up: information-schema

19.6 The `INFORMATION_SCHEMA KEY_COLUMN_USAGE' Table
====================================================

The *Note `KEY_COLUMN_USAGE': key-column-usage-table. table describes
which key columns have constraints.

`INFORMATION_SCHEMA' Name     *Note `SHOW': show.    Remarks
                              Name                   
`CONSTRAINT_CATALOG'                                 `NULL'
`CONSTRAINT_SCHEMA'                                  
`CONSTRAINT_NAME'                                    
`TABLE_CATALOG'                                      
`TABLE_SCHEMA'                                       
`TABLE_NAME'                                         
`COLUMN_NAME'                                        
`ORDINAL_POSITION'                                   
`POSITION_IN_UNIQUE_CONSTRAINT'                       
`REFERENCED_TABLE_SCHEMA'                            
`REFERENCED_TABLE_NAME'                              
`REFERENCED_COLUMN_NAME'                             

*Notes*:

   * If the constraint is a foreign key, then this is the column of the
     foreign key, not the column that the foreign key references.

   * The value of `ORDINAL_POSITION' is the column's position within
     the constraint, not the column's position within the table. Column
     positions are numbered beginning with 1.

   * The value of `POSITION_IN_UNIQUE_CONSTRAINT' is `NULL' for unique
     and primary-key constraints. For foreign-key constraints, it is
     the ordinal position in key of the table that is being referenced.

     Suppose that there are two tables name `t1' and `t3' that have the
     following definitions:

          CREATE TABLE t1
          (
              s1 INT,
              s2 INT,
              s3 INT,
              PRIMARY KEY(s3)
          ) ENGINE=InnoDB;

          CREATE TABLE t3
          (
              s1 INT,
              s2 INT,
              s3 INT,
              KEY(s1),
              CONSTRAINT CO FOREIGN KEY (s2) REFERENCES t1(s3)
          ) ENGINE=InnoDB;

     For those two tables, the *Note `KEY_COLUMN_USAGE':
     key-column-usage-table. table has two rows:

        * One row with `CONSTRAINT_NAME' = `'PRIMARY'', `TABLE_NAME' =
          `'t1'', `COLUMN_NAME' = `'s3'', `ORDINAL_POSITION' = `1',
          `POSITION_IN_UNIQUE_CONSTRAINT' = `NULL'.

        * One row with `CONSTRAINT_NAME' = `'CO'', `TABLE_NAME' =
          `'t3'', `COLUMN_NAME' = `'s2'', `ORDINAL_POSITION' = `1',
          `POSITION_IN_UNIQUE_CONSTRAINT' = `1'.

   * `REFERENCED_TABLE_SCHEMA', `REFERENCED_TABLE_NAME', and
     `REFERENCED_COLUMN_NAME' were added in MySQL 5.0.6.


File: manual.info,  Node: profiling-table,  Next: routines-table,  Prev: key-column-usage-table,  Up: information-schema

19.7 The `INFORMATION_SCHEMA PROFILING' Table
=============================================

The `PROFILING' table provides statement profiling information. Its
contents correspond to the information produced by the *Note `SHOW
PROFILES': show-profiles. and *Note `SHOW PROFILE': show-profile.
statements (see *Note show-profiles::). The table is empty unless the
`profiling' session variable is set to 1.

`INFORMATION_SCHEMA' Name     *Note `SHOW': show.    Remarks
                              Name                   
`QUERY_ID'                    `Query_ID'             
`SEQ'                         `'                     
`STATE'                       `Status'               
`DURATION'                    `Duration'             
`CPU_USER'                    `CPU_user'             
`CPU_SYSTEM'                  `CPU_system'           
`CONTEXT_VOLUNTARY'           `Context_voluntary'    
`CONTEXT_INVOLUNTARY'         `Context_involuntary'  
`BLOCK_OPS_IN'                `Block_ops_in'         
`BLOCK_OPS_OUT'               `Block_ops_out'        
`MESSAGES_SENT'               `Messages_sent'        
`MESSAGES_RECEIVED'           `Messages_received'    
`PAGE_FAULTS_MAJOR'           `Page_faults_major'    
`PAGE_FAULTS_MINOR'           `Page_faults_minor'    
`SWAPS'                       `Swaps'                
`SOURCE_FUNCTION'             `Source_function'      
`SOURCE_FILE'                 `Source_file'          
`SOURCE_LINE'                 `Source_line'          

*Notes*:

   * The `PROFILING' table was added in MySQL 5.0.37.

   * `QUERY_ID' is a numeric statement identifier.

   * `SEQ' is a sequence number indicating the display order for rows
     with the same `QUERY_ID' value.

   * `STATE' is the profiling state to which the row measurements apply.

   * `DURATION' indicates how long statement execution remained in the
     given state, in seconds.

   * `CPU_USER' and `CPU_SYSTEM' indicate user and system CPU use, in
     seconds.

   * `CONTEXT_VOLUNTARY' and `CONTEXT_INVOLUNTARY' indicate how many
     voluntary and involuntary context switches occurred.

   * `BLOCK_OPS_IN' and `BLOCK_OPS_OUT' indicate the number of block
     input and output operations.

   * `MESSAGES_SENT' and `MESSAGES_RECEIVED' indicate the number of
     communication messages sent and received.

   * `PAGE_FAULTS_MAJOR' and `PAGE_FAULTS_MINOR' indicate the number of
     major and minor page faults.

   * `SWAPS' indicates how many swaps occurred.

   * `SOURCE_FUNCTION', `SOURCE_FILE', and `SOURCE_LINE' provide
     information indicating where in the source code the profiled state
     executes.


File: manual.info,  Node: routines-table,  Next: schemata-table,  Prev: profiling-table,  Up: information-schema

19.8 The `INFORMATION_SCHEMA ROUTINES' Table
============================================

The *Note `ROUTINES': routines-table. table provides information about
stored routines (both procedures and functions).  The *Note `ROUTINES':
routines-table. table does not include user-defined functions (UDFs).

The column named ``mysql.proc' name' indicates the `mysql.proc' table
column that corresponds to the *Note `INFORMATION_SCHEMA.ROUTINES':
routines-table. table column, if any.

`INFORMATION_SCHEMA' Name     `mysql.proc' Name      Remarks
`SPECIFIC_NAME'               `specific_name'        
`ROUTINE_CATALOG'                                    `NULL'
`ROUTINE_SCHEMA'              `db'                   
`ROUTINE_NAME'                `name'                 
`ROUTINE_TYPE'                `type'                 `{PROCEDURE|FUNCTION}'
`DTD_IDENTIFIER'                                     data type descriptor
`ROUTINE_BODY'                                       `SQL'
`ROUTINE_DEFINITION'          `body'                 
`EXTERNAL_NAME'                                      `NULL'
`EXTERNAL_LANGUAGE'           `language'             `NULL'
`PARAMETER_STYLE'                                    `SQL'
`IS_DETERMINISTIC'            `is_deterministic'     
`SQL_DATA_ACCESS'             `sql_data_access'      
`SQL_PATH'                                           `NULL'
`SECURITY_TYPE'               `security_type'        
`CREATED'                     `created'              
`LAST_ALTERED'                `modified'             
`SQL_MODE'                    `sql_mode'             MySQL extension
`ROUTINE_COMMENT'             `comment'              MySQL extension
`DEFINER'                     `definer'              MySQL extension

*Notes*:

   * MySQL calculates `EXTERNAL_LANGUAGE' thus:

        * If `mysql.proc.language='SQL'', `EXTERNAL_LANGUAGE' is `NULL'

        * Otherwise, `EXTERNAL_LANGUAGE' is what is in
          `mysql.proc.language'. However, we do not have external
          languages yet, so it is always `NULL'.


File: manual.info,  Node: schemata-table,  Next: schema-privileges-table,  Prev: routines-table,  Up: information-schema

19.9 The `INFORMATION_SCHEMA SCHEMATA' Table
============================================

A schema is a database, so the *Note `SCHEMATA': schemata-table. table
provides information about databases.

`INFORMATION_SCHEMA' Name     *Note `SHOW': show.    Remarks
                              Name                   
`CATALOG_NAME'                                       `NULL'
`SCHEMA_NAME'                                        Database
`DEFAULT_CHARACTER_SET_NAME'                         
`DEFAULT_COLLATION_NAME'                             
`SQL_PATH'                                           `NULL'

*Notes*:

   * `DEFAULT_COLLATION_NAME' was added in MySQL 5.0.6.

The following statements are equivalent:

     SELECT SCHEMA_NAME AS `Database`
       FROM INFORMATION_SCHEMA.SCHEMATA
       [WHERE SCHEMA_NAME LIKE 'WILD']

     SHOW DATABASES
       [LIKE 'WILD']


File: manual.info,  Node: schema-privileges-table,  Next: statistics-table,  Prev: schemata-table,  Up: information-schema

19.10 The `INFORMATION_SCHEMA SCHEMA_PRIVILEGES' Table
======================================================

The *Note `SCHEMA_PRIVILEGES': schema-privileges-table. table provides
information about schema (database) privileges. This information comes
from the `mysql.db' grant table.

`INFORMATION_SCHEMA' Name     *Note `SHOW': show.    Remarks
                              Name                   
`GRANTEE'                                            `'USER_NAME'@'HOST_NAME''
                                                     value, MySQL extension
`TABLE_CATALOG'                                      `NULL', MySQL
                                                     extension
`TABLE_SCHEMA'                                       MySQL extension
`PRIVILEGE_TYPE'                                     MySQL extension
`IS_GRANTABLE'                                       MySQL extension

*Notes*:

   * This is a nonstandard table. It takes its values from the
     `mysql.db' table.


File: manual.info,  Node: statistics-table,  Next: tables-table,  Prev: schema-privileges-table,  Up: information-schema

19.11 The `INFORMATION_SCHEMA STATISTICS' Table
===============================================

The *Note `STATISTICS': statistics-table. table provides information
about table indexes.

`INFORMATION_SCHEMA' Name     *Note `SHOW': show.    Remarks
                              Name                   
`TABLE_CATALOG'                                      `NULL'
`TABLE_SCHEMA'                                       = Database
`TABLE_NAME'                  `Table'                
`NON_UNIQUE'                  `Non_unique'           
`INDEX_SCHEMA'                                       = Database
`INDEX_NAME'                  `Key_name'             
`SEQ_IN_INDEX'                `Seq_in_index'         
`COLUMN_NAME'                 `Column_name'          
`COLLATION'                   `Collation'            
`CARDINALITY'                 `Cardinality'          
`SUB_PART'                    `Sub_part'             MySQL extension
`PACKED'                      `Packed'               MySQL extension
`NULLABLE'                    `Null'                 MySQL extension
`INDEX_TYPE'                  `Index_type'           MySQL extension
`COMMENT'                     `Comment'              MySQL extension

*Notes*:

   * There is no standard table for indexes. The preceding list is
     similar to what SQL Server 2000 returns for `sp_statistics',
     except that we replaced the name `QUALIFIER' with `CATALOG' and we
     replaced the name `OWNER' with `SCHEMA'.

     Clearly, the preceding table and the output from *Note `SHOW
     INDEX': show-index. are derived from the same parent. So the
     correlation is already close.

The following statements are equivalent:

     SELECT * FROM INFORMATION_SCHEMA.STATISTICS
       WHERE table_name = 'TBL_NAME'
       AND table_schema = 'DB_NAME'

     SHOW INDEX
       FROM TBL_NAME
       FROM DB_NAME


File: manual.info,  Node: tables-table,  Next: table-constraints-table,  Prev: statistics-table,  Up: information-schema

19.12 The `INFORMATION_SCHEMA TABLES' Table
===========================================

The *Note `TABLES': tables-table. table provides information about
tables in databases.

`INFORMATION_SCHEMA' Name     *Note `SHOW': show.    Remarks
                              Name                   
`TABLE_CATALOG'                                      `NULL'
`TABLE_SCHEMA'                `Table_'...            
`TABLE_NAME'                  `Table_'...            
`TABLE_TYPE'                                         
`ENGINE'                      `Engine'               MySQL extension
`VERSION'                     `Version'              The version number of
                                                     the table's `.frm'
                                                     file, MySQL extension
`ROW_FORMAT'                  `Row_format'           MySQL extension
`TABLE_ROWS'                  `Rows'                 MySQL extension
`AVG_ROW_LENGTH'              `Avg_row_length'       MySQL extension
`DATA_LENGTH'                 `Data_length'          MySQL extension
`MAX_DATA_LENGTH'             `Max_data_length'      MySQL extension
`INDEX_LENGTH'                `Index_length'         MySQL extension
`DATA_FREE'                   `Data_free'            MySQL extension
`AUTO_INCREMENT'              `Auto_increment'       MySQL extension
`CREATE_TIME'                 `Create_time'          MySQL extension
`UPDATE_TIME'                 `Update_time'          MySQL extension
`CHECK_TIME'                  `Check_time'           MySQL extension
`TABLE_COLLATION'             `Collation'            MySQL extension
`CHECKSUM'                    `Checksum'             MySQL extension
`CREATE_OPTIONS'              `Create_options'       MySQL extension
`TABLE_COMMENT'               `Comment'              MySQL extension

*Notes*:

   * `TABLE_SCHEMA' and `TABLE_NAME' are a single field in a *Note
     `SHOW': show. display, for example `Table_in_db1'.

   * `TABLE_TYPE' should be `BASE TABLE' or `VIEW'. Currently, the
     *Note `TABLES': tables-table. table does not list `TEMPORARY'
     tables.

   * The `TABLE_ROWS' column is `NULL' if the table is in the
     `INFORMATION_SCHEMA' database.

     For *Note `InnoDB': innodb-storage-engine. tables, the row count
     is only a rough estimate used in SQL optimization.

   * We have nothing for the table's default character set.
     `TABLE_COLLATION' is close, because collation names begin with a
     character set name.

The following statements are equivalent:

     SELECT table_name FROM INFORMATION_SCHEMA.TABLES
       WHERE table_schema = 'DB_NAME'
       [AND table_name LIKE 'WILD']

     SHOW TABLES
       FROM DB_NAME
       [LIKE 'WILD']


File: manual.info,  Node: table-constraints-table,  Next: table-privileges-table,  Prev: tables-table,  Up: information-schema

19.13 The `INFORMATION_SCHEMA TABLE_CONSTRAINTS' Table
======================================================

The *Note `TABLE_CONSTRAINTS': table-constraints-table. table describes
which tables have constraints.

`INFORMATION_SCHEMA' Name     *Note `SHOW': show.    Remarks
                              Name                   
`CONSTRAINT_CATALOG'                                 `NULL'
`CONSTRAINT_SCHEMA'                                  
`CONSTRAINT_NAME'                                    
`TABLE_SCHEMA'                                       
`TABLE_NAME'                                         
`CONSTRAINT_TYPE'                                    

*Notes*:

   * The `CONSTRAINT_TYPE' value can be `UNIQUE', `PRIMARY KEY', or
     `FOREIGN KEY'.

   * The `UNIQUE' and `PRIMARY KEY' information is about the same as
     what you get from the `Key_name' field in the output from *Note
     `SHOW INDEX': show-index. when the `Non_unique' field is `0'.

   * The `CONSTRAINT_TYPE' column can contain one of these values:
     `UNIQUE', `PRIMARY KEY', `FOREIGN KEY', `CHECK'. This is a *Note
     `CHAR': char. (not *Note `ENUM': enum.) column. The `CHECK' value
     is not available until we support `CHECK'.


File: manual.info,  Node: table-privileges-table,  Next: triggers-table,  Prev: table-constraints-table,  Up: information-schema

19.14 The `INFORMATION_SCHEMA TABLE_PRIVILEGES' Table
=====================================================

The *Note `TABLE_PRIVILEGES': table-privileges-table. table provides
information about table privileges. This information comes from the
`mysql.tables_priv' grant table.

`INFORMATION_SCHEMA' Name     *Note `SHOW': show.    Remarks
                              Name                   
`GRANTEE'                                            `'USER_NAME'@'HOST_NAME''
                                                     value
`TABLE_CATALOG'                                      `NULL'
`TABLE_SCHEMA'                                       
`TABLE_NAME'                                         
`PRIVILEGE_TYPE'                                     
`IS_GRANTABLE'                                       

*Notes*:

   * `PRIVILEGE_TYPE' can contain one (and only one) of these values:
     `SELECT', `INSERT', `UPDATE', `REFERENCES', `ALTER', `INDEX',
     `DROP', `CREATE VIEW'.

The following statements are _not_ equivalent:

     SELECT ... FROM INFORMATION_SCHEMA.TABLE_PRIVILEGES

     SHOW GRANTS ...


File: manual.info,  Node: triggers-table,  Next: user-privileges-table,  Prev: table-privileges-table,  Up: information-schema

19.15 The `INFORMATION_SCHEMA TRIGGERS' Table
=============================================

The *Note `TRIGGERS': triggers-table. table provides information about
triggers. You must have the `SUPER' privilege to access this table. You
can see results only if you have the `SUPER' privilege).

`INFORMATION_SCHEMA' Name     *Note `SHOW': show.    Remarks
                              Name                   
`TRIGGER_CATALOG'                                    `NULL'
`TRIGGER_SCHEMA'                                     
`TRIGGER_NAME'                `Trigger'              
`EVENT_MANIPULATION'          `Event'                
`EVENT_OBJECT_CATALOG'                               `NULL'
`EVENT_OBJECT_SCHEMA'                                
`EVENT_OBJECT_TABLE'          `Table'                
`ACTION_ORDER'                                       `0'
`ACTION_CONDITION'                                   `NULL'
`ACTION_STATEMENT'            `Statement'            
`ACTION_ORIENTATION'                                 `ROW'
`ACTION_TIMING'               `Timing'               
`ACTION_REFERENCE_OLD_TABLE'                         `NULL'
`ACTION_REFERENCE_NEW_TABLE'                         `NULL'
`ACTION_REFERENCE_OLD_ROW'                           `OLD'
`ACTION_REFERENCE_NEW_ROW'                           `NEW'
`CREATED'                                            `NULL' (`0')
`SQL_MODE'                                           MySQL extension
`DEFINER'                                            MySQL extension

*Notes*:

   * The *Note `TRIGGERS': triggers-table. table was added in MySQL
     5.0.10.

   * The `TRIGGER_SCHEMA' and `TRIGGER_NAME' columns contain the name of
     the database in which the trigger occurs and the trigger name,
     respectively.

   * The `EVENT_MANIPULATION' column contains one of the values
     `'INSERT'', `'DELETE'', or `'UPDATE''.

   * As noted in *Note triggers::, every trigger is associated with
     exactly one table. The `EVENT_OBJECT_SCHEMA' and
     `EVENT_OBJECT_TABLE' columns contain the database in which this
     table occurs, and the table's name.

   * The `ACTION_ORDER' column contains the ordinal position of the
     trigger's action within the list of all similar triggers on the
     same table. Currently, this value is always `0', because it is not
     possible to have more than one trigger with the same
     `EVENT_MANIPULATION' and `ACTION_TIMING' on the same table.

   * The `ACTION_STATEMENT' column contains the statement to be
     executed when the trigger is invoked. This is the same as the text
     displayed in the `Statement' column of the output from *Note `SHOW
     TRIGGERS': show-triggers. Note that this text uses UTF-8 encoding.

   * The `ACTION_ORIENTATION' column always contains the value `'ROW''.

   * The `ACTION_TIMING' column contains one of the two values
     `'BEFORE'' or `'AFTER''.

   * The columns `ACTION_REFERENCE_OLD_ROW' and
     `ACTION_REFERENCE_NEW_ROW' contain the old and new column
     identifiers, respectively. This means that
     `ACTION_REFERENCE_OLD_ROW' always contains the value `'OLD'' and
     `ACTION_REFERENCE_NEW_ROW' always contains the value `'NEW''.

   * The `SQL_MODE' column shows the server SQL mode that was in effect
     at the time when the trigger was created (and thus which remains
     in effect for this trigger whenever it is invoked, _regardless of
     the current server SQL mode_). The possible range of values for
     this column is the same as that of the `sql_mode' system variable.
     See *Note server-sql-mode::.

   * The `DEFINER' column was added in MySQL 5.0.17. `DEFINER'
     indicates who defined the trigger.

   * The following columns currently always contain `NULL':
     `TRIGGER_CATALOG', `EVENT_OBJECT_CATALOG', `ACTION_CONDITION',
     `ACTION_REFERENCE_OLD_TABLE', `ACTION_REFERENCE_NEW_TABLE', and
     `CREATED'.

Example, using the `ins_sum' trigger defined in *Note triggers:::

     mysql> SELECT * FROM INFORMATION_SCHEMA.TRIGGERS\G
     *************************** 1. row ***************************
                TRIGGER_CATALOG: NULL
                 TRIGGER_SCHEMA: test
                   TRIGGER_NAME: ins_sum
             EVENT_MANIPULATION: INSERT
           EVENT_OBJECT_CATALOG: NULL
            EVENT_OBJECT_SCHEMA: test
             EVENT_OBJECT_TABLE: account
                   ACTION_ORDER: 0
               ACTION_CONDITION: NULL
               ACTION_STATEMENT: SET @sum = @sum + NEW.amount
             ACTION_ORIENTATION: ROW
                  ACTION_TIMING: BEFORE
     ACTION_REFERENCE_OLD_TABLE: NULL
     ACTION_REFERENCE_NEW_TABLE: NULL
       ACTION_REFERENCE_OLD_ROW: OLD
       ACTION_REFERENCE_NEW_ROW: NEW
                        CREATED: NULL
                       SQL_MODE:
                        DEFINER: me@localhost

See also *Note show-triggers::.


File: manual.info,  Node: user-privileges-table,  Next: views-table,  Prev: triggers-table,  Up: information-schema

19.16 The `INFORMATION_SCHEMA USER_PRIVILEGES' Table
====================================================

The *Note `USER_PRIVILEGES': user-privileges-table. table provides
information about global privileges. This information comes from the
`mysql.user' grant table.

`INFORMATION_SCHEMA' Name     *Note `SHOW': show.    Remarks
                              Name                   
`GRANTEE'                                            `'USER_NAME'@'HOST_NAME''
                                                     value, MySQL extension
`TABLE_CATALOG'                                      `NULL', MySQL
                                                     extension
`PRIVILEGE_TYPE'                                     MySQL extension
`IS_GRANTABLE'                                       MySQL extension

*Notes*:

   * This is a nonstandard table. It takes its values from the
     `mysql.user' table.


File: manual.info,  Node: views-table,  Next: other-information-schema-tables,  Prev: user-privileges-table,  Up: information-schema

19.17 The `INFORMATION_SCHEMA VIEWS' Table
==========================================

The *Note `VIEWS': views-table. table provides information about views
in databases. You must have the `SHOW VIEW' privilege to access this
table.

`INFORMATION_SCHEMA' Name     *Note `SHOW': show.    Remarks
                              Name                   
`TABLE_CATALOG'                                      `NULL'
`TABLE_SCHEMA'                                       
`TABLE_NAME'                                         
`VIEW_DEFINITION'                                    
`CHECK_OPTION'                                       
`IS_UPDATABLE'                                       
`DEFINER'                                            
`SECURITY_TYPE'                                      

*Notes*:

   * The `VIEW_DEFINITION' column has most of what you see in the
     `Create Table' field that *Note `SHOW CREATE VIEW':
     show-create-view. produces. Skip the words before *Note `SELECT':
     select. and skip the words `WITH CHECK OPTION'. Suppose that the
     original statement was:

          CREATE VIEW v AS
            SELECT s2,s1 FROM t
            WHERE s1 > 5
            ORDER BY s1
            WITH CHECK OPTION;

     Then the view definition looks like this:

          SELECT s2,s1 FROM t WHERE s1 > 5 ORDER BY s1

   * The `CHECK_OPTION' column has a value of `NONE', `CASCADE', or
     `LOCAL'.

   * MySQL sets a flag, called the view updatability flag, at *Note
     `CREATE VIEW': create-view. time. The flag is set to `YES' (true)
     if *Note `UPDATE': update. and *Note `DELETE': delete. (and
     similar operations) are legal for the view. Otherwise, the flag is
     set to `NO' (false). The `IS_UPDATABLE' column in the *Note
     `VIEWS': views-table. table displays the status of this flag. It
     means that the server always knows whether a view is updatable. If
     the view is not updatable, statements such *Note `UPDATE': update,
     *Note `DELETE': delete, and *Note `INSERT': insert. are illegal
     and will be rejected. (Note that even if a view is updatable, it
     might not be possible to insert into it; for details, refer to
     *Note create-view::.)

   * The `DEFINER' and `SECURITY_TYPE' columns were added in MySQL
     5.0.14. `DEFINER' indicates who defined the view. `SECURITY_TYPE'
     has a value of `DEFINER' or `INVOKER'.

MySQL lets you use different `sql_mode' settings to tell the server the
type of SQL syntax to support. For example, you might use the `ANSI'
SQL mode to ensure MySQL correctly interprets the standard SQL
concatenation operator, the double bar (`||'), in your queries.  If you
then create a view that concatenates items, you might worry that
changing the `sql_mode' setting to a value different from `ANSI' could
cause the view to become invalid. But this is not the case. No matter
how you write out a view definition, MySQL always stores it the same
way, in a canonical form. Here is an example that shows how the server
changes a double bar concatenation operator to a `CONCAT()' function:

     mysql> SET sql_mode = 'ANSI';
     Query OK, 0 rows affected (0.00 sec)

     mysql> CREATE VIEW test.v AS SELECT 'a' || 'b' as col1;
     Query OK, 0 rows affected (0.00 sec)

     mysql> SELECT VIEW_DEFINITION FROM INFORMATION_SCHEMA.VIEWS
         -> WHERE TABLE_SCHEMA = 'test' AND TABLE_NAME = 'v';
     +----------------------------------+
     | VIEW_DEFINITION                  |
     +----------------------------------+
     | select concat('a','b') AS `col1` |
     +----------------------------------+
     1 row in set (0.00 sec)

The advantage of storing a view definition in canonical form is that
changes made later to the value of `sql_mode' will not affect the
results from the view. However an additional consequence is that
comments prior to *Note `SELECT': select. are stripped from the
definition by the server.


File: manual.info,  Node: other-information-schema-tables,  Next: extended-show,  Prev: views-table,  Up: information-schema

19.18 Other `INFORMATION_SCHEMA' Tables
=======================================

We intend to implement additional `INFORMATION_SCHEMA' tables. In
particular, we acknowledge the need for the `PARAMETERS' and
`REFERENTIAL_CONSTRAINTS' tables.  (`REFERENTIAL_CONSTRAINTS' is
implemented in MySQL 5.1, and `PARAMETERS' is implemented in MySQL 5.5.)


File: manual.info,  Node: extended-show,  Prev: other-information-schema-tables,  Up: information-schema

19.19 Extensions to `SHOW' Statements
=====================================

Some extensions to *Note `SHOW': show. statements accompany the
implementation of `INFORMATION_SCHEMA':

   * *Note `SHOW': show. can be used to get information about the
     structure of `INFORMATION_SCHEMA' itself.

   * Several *Note `SHOW': show. statements accept a `WHERE' clause
     that provides more flexibility in specifying which rows to display.

These extensions are available beginning with MySQL 5.0.3.

`INFORMATION_SCHEMA' is an information database, so its name is
included in the output from *Note `SHOW DATABASES': show-databases.
Similarly, *Note `SHOW TABLES': show-tables. can be used with
`INFORMATION_SCHEMA' to obtain a list of its tables:

     mysql> SHOW TABLES FROM INFORMATION_SCHEMA;
     +---------------------------------------+
     | Tables_in_information_schema          |
     +---------------------------------------+
     | CHARACTER_SETS                        |
     | COLLATIONS                            |
     | COLLATION_CHARACTER_SET_APPLICABILITY |
     | COLUMNS                               |
     | COLUMN_PRIVILEGES                     |
     | KEY_COLUMN_USAGE                      |
     | ROUTINES                              |
     | SCHEMATA                              |
     | SCHEMA_PRIVILEGES                     |
     | STATISTICS                            |
     | TABLES                                |
     | TABLE_CONSTRAINTS                     |
     | TABLE_PRIVILEGES                      |
     | TRIGGERS                              |
     | USER_PRIVILEGES                       |
     | VIEWS                                 |
     +---------------------------------------+
     16 rows in set (0.00 sec)

*Note `SHOW COLUMNS': show-columns. and *Note `DESCRIBE': describe. can
display information about the columns in individual
`INFORMATION_SCHEMA' tables.

*Note `SHOW': show. statements that accept a `LIKE' clause to limit the
rows displayed also have been extended to permit a `WHERE' clause that
specifies more general conditions that selected rows must satisfy:

     SHOW CHARACTER SET
     SHOW COLLATION
     SHOW COLUMNS
     SHOW DATABASES
     SHOW FUNCTION STATUS
     SHOW INDEX
     SHOW OPEN TABLES
     SHOW PROCEDURE STATUS
     SHOW STATUS
     SHOW TABLE STATUS
     SHOW TABLES
     SHOW VARIABLES

The `WHERE' clause, if present, is evaluated against the column names
displayed by the *Note `SHOW': show. statement. For example, the *Note
`SHOW CHARACTER SET': show-character-set. statement produces these
output columns:

     mysql> SHOW CHARACTER SET;
     +----------+-----------------------------+---------------------+--------+
     | Charset  | Description                 | Default collation   | Maxlen |
     +----------+-----------------------------+---------------------+--------+
     | big5     | Big5 Traditional Chinese    | big5_chinese_ci     |      2 |
     | dec8     | DEC West European           | dec8_swedish_ci     |      1 |
     | cp850    | DOS West European           | cp850_general_ci    |      1 |
     | hp8      | HP West European            | hp8_english_ci      |      1 |
     | koi8r    | KOI8-R Relcom Russian       | koi8r_general_ci    |      1 |
     | latin1   | cp1252 West European        | latin1_swedish_ci   |      1 |
     | latin2   | ISO 8859-2 Central European | latin2_general_ci   |      1 |
     ...

To use a `WHERE' clause with *Note `SHOW CHARACTER SET':
show-character-set, you would refer to those column names. As an
example, the following statement displays information about character
sets for which the default collation contains the string `'japanese'':

     mysql> SHOW CHARACTER SET WHERE `Default collation` LIKE '%japanese%';
     +---------+---------------------------+---------------------+--------+
     | Charset | Description               | Default collation   | Maxlen |
     +---------+---------------------------+---------------------+--------+
     | ujis    | EUC-JP Japanese           | ujis_japanese_ci    |      3 |
     | sjis    | Shift-JIS Japanese        | sjis_japanese_ci    |      2 |
     | cp932   | SJIS for Windows Japanese | cp932_japanese_ci   |      2 |
     | eucjpms | UJIS for Windows Japanese | eucjpms_japanese_ci |      3 |
     +---------+---------------------------+---------------------+--------+

This statement displays the multi-byte character sets:

     mysql> SHOW CHARACTER SET WHERE Maxlen > 1;
     +---------+---------------------------+---------------------+--------+
     | Charset | Description               | Default collation   | Maxlen |
     +---------+---------------------------+---------------------+--------+
     | big5    | Big5 Traditional Chinese  | big5_chinese_ci     |      2 |
     | ujis    | EUC-JP Japanese           | ujis_japanese_ci    |      3 |
     | sjis    | Shift-JIS Japanese        | sjis_japanese_ci    |      2 |
     | euckr   | EUC-KR Korean             | euckr_korean_ci     |      2 |
     | gb2312  | GB2312 Simplified Chinese | gb2312_chinese_ci   |      2 |
     | gbk     | GBK Simplified Chinese    | gbk_chinese_ci      |      2 |
     | utf8    | UTF-8 Unicode             | utf8_general_ci     |      3 |
     | ucs2    | UCS-2 Unicode             | ucs2_general_ci     |      2 |
     | cp932   | SJIS for Windows Japanese | cp932_japanese_ci   |      2 |
     | eucjpms | UJIS for Windows Japanese | eucjpms_japanese_ci |      3 |
     +---------+---------------------------+---------------------+--------+


File: manual.info,  Node: connectors-apis,  Next: extending-mysql,  Prev: information-schema,  Up: Top

20 Connectors and APIs
**********************

* Menu:

* connector-odbc::               MySQL Connector/ODBC
* connector-net::                MySQL Connector/Net
* connector-j::                  MySQL Connector/J
* connector-mxj::                MySQL Connector/MXJ
* connector-c::                  MySQL Connector/C
* connector-ooo::                MySQL Connector/OpenOffice.org
* libmysqld::                    libmysqld, the Embedded MySQL Server Library
* c::                            MySQL C API
* apis-php::                     MySQL PHP API
* apis-perl::                    MySQL Perl API
* apis-python::                  MySQL Python API
* apis-ruby::                    MySQL Ruby APIs
* apis-tcl::                     MySQL Tcl API
* apis-eiffel::                  MySQL Eiffel Wrapper

MySQL Connectors provide connectivity to the MySQL server for client
programs. APIs provide low-level access to the MySQL protocol and MySQL
resources. Both Connectors and the APIs enable you to connect and
execute MySQL statements from another language or environment,
including Java (JDBC), ODBC, Perl, Python, PHP, Ruby, and native C and
embedded MySQL instances.

*Note*:

Connector version numbers do not correlate with MySQL Server version
numbers. See also *Note connectors-apis-versions::.

A number of connectors are developed by MySQL:

   * Connector/ODBC provides driver support for connecting to a MySQL
     server using the Open Database Connectivity (ODBC) API. Support is
     available for ODBC connectivity from Windows, Unix and Mac OS X
     platforms.

   * Connector/Net enables developers to create .NET applications that
     use data stored in a MySQL database. Connector/Net implement a
     fully functional ADO.NET interface and provides support for use
     with ADO.NET aware tools. Applications that want to use
     Connector/Net can be written in any of the supported .NET
     languages.

     The MySQL Visual Studio Plugin works with Connector/Net and Visual
     Studio 2005. The plugin is a MySQL DDEX Provider, which means that
     you can use the schema and data manipulation tools within Visual
     Studio to create and edit objects within a MySQL database.

   * Connector/J provides driver support for connecting to MySQL from a
     Java application using the standard Java Database Connectivity
     (JDBC) API.

   * Connector/MXJ is a tool that enables easy deployment and
     management of MySQL server and database through your Java
     application.

   * Connector/C++ is a tool that enables easy deployment and
     management of MySQL server and database through your C++
     application.

   * Connector/C is a standalone replacement for the MySQL Client
     Library (`libmysql').

   * Connector/OpenOffice.org is a tool that enables OpenOffice.org
     applications to connect to MySQL server.

There are two direct access methods for using MySQL natively within a C
application:

   * The C API provides low-level access to the MySQL protocol through
     the `libmysql' client library; this is the primary method used to
     connect to an instance of the MySQL server, and is used both by
     MySQL command line clients and many of the APIs also detailed in
     this section. MySQL Connector/C can now also be used for this
     purpose.

   * `libmysqld' is an embedded MySQL server library that enables you
     to embed an instance of the MySQL server into your C applications.

If you need to access MySQL from a C application, or build an interface
to MySQL for a language not supported by the Connectors or APIs in this
chapter, the C API is where you would start. A number of programmers
utilities are available to help with the process, and also covered in
this section.

The remaining APIs provide an interface to MySQL from specific
application languages. These solutions are not developed or supported
by MySQL. Basic information on their usage and abilities is provided
here for reference purposes only.

All the language APIs are developed using one of two methods, using
`libmysql' or by building a _native driver_. The two solutions offer
different benefits:

   * Using _`libmysql'_ offers complete compatibility with MySQL as it
     uses the same libraries as the MySQL client applications. However,
     the feature set is limited to the implementation and interfaces
     exposed through `libmysql' and the performance may be lower as
     data is copied between the native language, and the MySQL API
     components. MySQL Connector/C is a possible alternative to using
     `libmysql'.

   * _Native drivers_ are an implementation of the MySQL network
     protocol entirely within the host language or environment. Native
     drivers are fast, as there is less copying of data between
     components, and they can offer advanced functionality not
     available through the standard MySQL API.  Native drivers are also
     easier to build and deploy, as you do not need a copy of the MySQL
     client libraries to build the native driver components.

A list of many of the libraries and interfaces available for MySQL are
shown in the table. See *Note connectors-apis-summary::.

*MySQL APIs and Interfaces*

EnvironmentAPI                       Type        Notes
Ada     MySQL Bindings for GNU    `libmysql'  See MySQL Bindings for GNU
        Ada                                   Ada
                                              (http://gnade.sourceforge.net/)
C       Connector/C               Replacement See *Note connector-c::.
                                  for         
                                  `libmysql'  
C++     Connector/C++             `libmysql'  See MySQL Connector/C++
                                              (http://dev.mysql.com/doc/refman/common/en/connector-cpp.html).
        MySQL++                   `libmysql'  See MySQL++ Web site
                                              (http://tangentsoft.net/mysql++/doc/).
        MySQL wrapped             `libmysql'  See MySQL wrapped
                                              (http://www.alhem.net/project/mysql/).
Cocoa   MySQL-Cocoa               `libmysql'  Compatible with the
                                              Objective-C Cocoa
                                              environment. See
                                              `http://mysql-cocoa.sourceforge.net/'
D       MySQL for D               `libmysql'  See MySQL for D
                                              (http://www.steinmole.de/d/).
Eiffel  Eiffel MySQL              `libmysql'  See *Note apis-eiffel::.
Erlang  `erlang-mysql-driver'     `libmysql'  See `erlang-mysql-driver'.
                                              (http://code.google.com/p/erlang-mysql-driver/)
Haskell Haskell MySQL Bindings    Native      See Brian O'Sullivan's pure
                                  Driver      Haskell MySQL bindings
                                              (http://www.serpentine.com/software/mysql).
        `hsql-mysql'              `libmysql'  See MySQL driver for Haskell
                                              (http://hackage.haskell.org/cgi-bin/hackage-scripts/package/hsql-mysql-1.7).
Java/JDBCConnector/J               Native      See *Note connector-j::.
                                  Driver      
Kaya    MyDB                      `libmysql'  See MyDB
                                              (http://kayalang.org/library/latest/MyDB).
Lua     LuaSQL                    `libmysql'  See LuaSQL
                                              (http://www.keplerproject.org/luasql/).
.NET/MonoConnector/Net             Native      See *Note connector-net::.
                                  Driver      
ObjectiveMySQL Bindings for        `libmysql'  See MySQL Bindings for
Caml    OBjective Caml                        Objective Caml
                                              (http://raevnos.pennmush.org/code/ocaml-mysql/).
Octave  Database bindings for     `libmysql'  See Database bindings for
        GNU Octave                            GNU Octave
                                              (http://octave.sourceforge.net/database/index.html).
ODBC    Connector/ODBC            `libmysql'  See *Note connector-odbc::.
OpenOfficeMySQL                     `libmysql'  Direct connectivity, without
        Connector/OpenOffice.org              using JDBC/ODBC. See *Note
                                              connector-ooo::.
Perl    `DBI'/`DBD::mysql'        `libmysql'  See *Note apis-perl::.
        `Net::MySQL'              Native      See `Net::MySQL'
                                  Driver      (http://search.cpan.org/dist/Net-MySQL/MySQL.pm)
                                              at CPAN
PHP     `mysql', `ext/mysql'      `libmysql'  See See section
        interface (deprecated)                "apis-php-mysql" in the
                                              online manual.
        `mysqli', `ext/mysqli'    `libmysql'  See See section
        interface                             "apis-php-mysqli" in the
                                              online manual.
        `PDO_MYSQL'               `libmysql'  See See section
                                              "apis-php-ref.pdo-mysql" in
                                              the online manual.
        PDO mysqlnd               Native      See PHP PDO `mysqlnd'.
                                  Driver      (http://forge.mysql.com/wiki/PHP_PDO_MYSQLND)
Python  MySQLdb                   `libmysql'  See *Note apis-python::.
Ruby    MySQL/Ruby                `libmysql'  Uses `libmysql'. See *Note
                                              apis-ruby-mysqlruby::.
        Ruby/MySQL                Native      See *Note
                                  Driver      apis-ruby-rubymysql::.
Scheme  `Myscsh'                  `libmysql'  See `Myscsh'
                                              (http://www-pu.informatik.uni-tuebingen.de/users/knauel/myscsh/).
SPL     `sql_mysql'               `libmysql'  See `sql_mysql' for SPL
                                              (http://www.clifford.at/spl/spldoc/sql_mysql.html).
Tcl     MySQLtcl                  `libmysql'  See *Note apis-tcl::.

*MySQL Connector Versions and MySQL Server Versions*

Connector                            Connector version  MySQL Server
                                                        version
Connector/C++                        1.0.5 GA           5.1, 5.4
Connector/OpenOffice.org             1.0 GA             5.0, 5.1, 5.4
Connector/J                          5.1.8              4.1, 5.0, 5.1, 5.4
Connector/Net                        1.0 (No longer     4.0, 5.0
                                     supported)         
Connector/Net                        5.2                5.0, 5.1, 5.4
Connector/Net                        6.0                5.0, 5.1, 5.4
Connector/Net                        6.1                5.0, 5.1, 5.4
Connector/ODBC                       3.51 (Unicode not  4.1, 5.0, 5.1, 5.4
                                     supported)         
Connector/ODBC                       5.1                4.1.1+, 5.0, 5.1,
                                                        5.4


File: manual.info,  Node: connector-odbc,  Next: connector-net,  Prev: connectors-apis,  Up: connectors-apis

20.1 MySQL Connector/ODBC
=========================

* Menu:

* connector-odbc-versions::      Connector/ODBC Versions
* connector-odbc-introduction::  Connector/ODBC Introduction
* connector-odbc-installation::  Connector/ODBC Installation
* connector-odbc-configuration::  Connector/ODBC Configuration
* connector-odbc-examples::      Connector/ODBC Examples
* connector-odbc-reference::     Connector/ODBC Reference
* connector-odbc-usagenotes::    Connector/ODBC Notes and Tips
* connector-odbc-support::       Connector/ODBC Support

The MySQL Connector/ODBC is the name for the family of MySQL ODBC
drivers (previously called MyODBC drivers) that provide access to a
MySQL database using the industry standard Open Database Connectivity
(ODBC) API. This reference covers Connector/ODBC 3.51 and
Connector/ODBC 5.1. Both releases provide an ODBC compliant interface
to MySQL Server.

MySQL Connector/ODBC provides both driver-manager based and native
interfaces to the MySQL database, with full support for MySQL
functionality, including stored procedures, transactions and, with
Connector/ODBC 5.1, full Unicode compliance.

For more information on the ODBC API standard and how to use it, refer
to `http://support.microsoft.com/kb/110093'.

The application development section of the ODBC API reference assumes a
good working knowledge of C, general DBMS, and a familiarity with
MySQL. For more information about MySQL functionality and its syntax,
refer to `http://dev.mysql.com/doc/'.

Typically, you need to install Connector/ODBC only on Windows machines.
For Unix and Mac OS X, you can use the native MySQL network or named
pipe to communicate with your MySQL database. You may need
Connector/ODBC for Unix or Mac OS X if you have an application that
requires an ODBC interface to communicate with the database.
Applications that require ODBC to communicate with MySQL include
ColdFusion, Microsoft Office, and Filemaker Pro.

*Key connector/ODBC topics include:*

   * Installing Connector/ODBC: *Note connector-odbc-installation::.

   * The configuration options: *Note
     connector-odbc-configuration-connection-parameters::.

   * An example that connects to a MySQL database from a Windows host:
     *Note connector-odbc-examples-walkthrough::.

   * An example that uses Microsoft Access as an interface to a MySQL
     database: *Note connector-odbc-examples-tools-with-access::.

   * General tips and notes, including how to obtain the last
     auto-increment ID: *Note connector-odbc-usagenotes-functionality::.

   * Application specific usage tips and notes: *Note
     connector-odbc-usagenotes-apptips::.

   * A FAQ (Frequently Asked Questions) list: *Note
     connector-odbc-errors::.

   * Additional Connector/ODBC support options: *Note
     connector-odbc-support::.


File: manual.info,  Node: connector-odbc-versions,  Next: connector-odbc-introduction,  Prev: connector-odbc,  Up: connector-odbc

20.1.1 Connector/ODBC Versions
------------------------------

There are currently two version of Connector/ODBC available:

   * Connector/ODBC 5.1, currently in GA status, is a partial rewrite
     of the of the 3.51 code base, and is designed to work with MySQL
     versions 4.1.1 and newer.

     Connector/ODBC 5.1 also includes the following changes and
     improvements over the 3.51 release:

        * Improved support on Windows 64-bit platforms.

        * Full Unicode support at the driver level. This includes
          support for the `SQL_WCHAR' data type, and support for
          Unicode login, password and DSN configurations. For more
          information,. see Microsoft Knowledgebase Article #716246
          (http://msdn2.microsoft.com/en-us/library/ms716246.aspx).

        * Support for the `SQL_NUMERIC_STRUCT' data type, which
          provides easier access to the precise definition of numeric
          values. For more information, see Microsoft Knowledgebase
          Article #714556
          (http://msdn2.microsoft.com/en-us/library/ms714556.aspx)

        * Native Windows setup library. This replaces the Qt library
          based interface for configuring DSN information within the
          ODBC Data Sources application.

        * Support for the ODBC descriptor, which improves the handling
          and metadata of columns and parameter data. For more
          information, see Microsoft Knowledgebase Article #716339
          (http://msdn2.microsoft.com/en-us/library/ms716339.aspx).

   * Connector/ODBC 3.51 is the current release of the 32-bit ODBC
     driver, also known as the MySQL ODBC 3.51 driver.  Connector/ODBC
     3.51 has support for ODBC 3.5x specification level 1 (complete
     core API + level 2 features) to continue to provide all
     functionality of ODBC for accessing MySQL.

The manual for versions of Connector/ODBC older than 3.51 can be
located in the corresponding binary or source distribution. Please note
that versions of Connector/ODBC earlier than the 3.51 revision were not
fully compliant with the ODBC specification.

*Note*:

From this section onward, the primary focus of this guide is the
Connector/ODBC 3.51 and Connector/ODBC 5.1 drivers.

*Note*:

Version numbers for MySQL products are formatted as X.X.X.  However,
Windows tools (Control Panel, properties display) may show the version
numbers as XX.XX.XX. For example, the official MySQL formatted version
number 5.0.9 may be displayed by Windows tools as 5.00.09. The two
versions are the same; only the number display format is different.


File: manual.info,  Node: connector-odbc-introduction,  Next: connector-odbc-installation,  Prev: connector-odbc-versions,  Up: connector-odbc

20.1.2 Connector/ODBC Introduction
----------------------------------

* Menu:

* connector-odbc-general-information::  General Information About ODBC and Connector/ODBC

ODBC (Open Database Connectivity) provides a way for client programs to
access a wide range of databases or data sources. ODBC is a
standardized API that enables connections to SQL database servers. It
was developed according to the specifications of the SQL Access Group
and defines a set of function calls, error codes, and data types that
can be used to develop database-independent applications. ODBC usually
is used when database independence or simultaneous access to different
data sources is required.

For more information about ODBC, refer to
`http://support.microsoft.com/kb/110093'.


File: manual.info,  Node: connector-odbc-general-information,  Prev: connector-odbc-introduction,  Up: connector-odbc-introduction

20.1.2.1 General Information About ODBC and Connector/ODBC
..........................................................

* Menu:

* connector-odbc-architecture::  Connector/ODBC Architecture
* connector-odbc-driver-manager::  ODBC Driver Managers

Open Database Connectivity (ODBC) is a widely accepted
application-programming interface (API) for database access. It is
based on the Call-Level Interface (CLI) specifications from X/Open and
ISO/IEC for database APIs and uses Structured Query Language (SQL) as
its database access language.

A survey of ODBC functions supported by Connector/ODBC is given at
*Note connector-odbc-reference-api::. For general information about
ODBC, see `http://support.microsoft.com/kb/110093'.


File: manual.info,  Node: connector-odbc-architecture,  Next: connector-odbc-driver-manager,  Prev: connector-odbc-general-information,  Up: connector-odbc-general-information

20.1.2.2 Connector/ODBC Architecture
....................................

The Connector/ODBC architecture is based on five components, as shown
in the following diagram:

Connector/ODBC Architecture

   * *Application:*

     The Application uses the ODBC API to access the data from the
     MySQL server. The ODBC API in turn uses the communicates with the
     Driver Manager. The Application communicates with the Driver
     Manager using the standard ODBC calls. The Application does not
     care where the data is stored, how it is stored, or even how the
     system is configured to access the data. It needs to know only the
     Data Source Name (DSN).

     A number of tasks are common to all applications, no matter how
     they use ODBC. These tasks are:

        * Selecting the MySQL server and connecting to it

        * Submitting SQL statements for execution

        * Retrieving results (if any)

        * Processing errors

        * Committing or rolling back the transaction enclosing the SQL
          statement

        * Disconnecting from the MySQL server

     Because most data access work is done with SQL, the primary tasks
     for applications that use ODBC are submitting SQL statements and
     retrieving any results generated by those statements.

   * *Driver manager:*

     The Driver Manager is a library that manages communication between
     application and driver or drivers. It performs the following tasks:

        * Resolves Data Source Names (DSN). The DSN is a configuration
          string that identifies a given database driver, database,
          database host and optionally authentication information that
          enables an ODBC application to connect to a database using a
          standardized reference.

          Because the database connectivity information is identified
          by the DSN, any ODBC compliant application can connect to the
          data source using the same DSN reference. This eliminates the
          need to separately configure each application that needs
          access to a given database; instead you instruct the
          application to use a pre-configured DSN.

        * Loading and unloading of the driver required to access a
          specific database as defined within the DSN. For example, if
          you have configured a DSN that connects to a MySQL database
          then the driver manager will load the Connector/ODBC driver
          to enable the ODBC API to communicate with the MySQL host.

        * Processes ODBC function calls or passes them to the driver
          for processing.

   * *Connector/ODBC Driver:*

     The Connector/ODBC driver is a library that implements the
     functions supported by the ODBC API. It processes ODBC function
     calls, submits SQL requests to MySQL server, and returns results
     back to the application. If necessary, the driver modifies an
     application's request so that the request conforms to syntax
     supported by MySQL.

   * *DSN Configuration:*

     The ODBC configuration file stores the driver and database
     information required to connect to the server. It is used by the
     Driver Manager to determine which driver to be loaded according to
     the definition in the DSN. The driver uses this to read connection
     parameters based on the DSN specified. For more information, *Note
     connector-odbc-configuration::.

   * *MySQL Server:*

     The MySQL database where the information is stored. The database
     is used as the source of the data (during queries) and the
     destination for data (during inserts and updates).


File: manual.info,  Node: connector-odbc-driver-manager,  Prev: connector-odbc-architecture,  Up: connector-odbc-general-information

20.1.2.3 ODBC Driver Managers
.............................

An ODBC Driver Manager is a library that manages communication between
the ODBC-aware application and any drivers. Its main functionality
includes:

   * Resolving Data Source Names (DSN).

   * Driver loading and unloading.

   * Processing ODBC function calls or passing them to the driver.

Both Windows and Mac OS X include ODBC driver managers with the
operating system. Most ODBC Driver Manager implementations also include
an administration application that makes the configuration of DSN and
drivers easier. Examples and information on these managers, including
Unix ODBC driver managers are listed below:

   * Microsoft Windows ODBC Driver Manager (`odbc32.dll'),
     `http://support.microsoft.com/kb/110093'.

   * Mac OS X includes `ODBC Administrator', a GUI application that
     provides a simpler configuration mechanism for the Unix iODBC
     Driver Manager. You can configure DSN and driver information
     either through ODBC Administrator or through the iODBC
     configuration files.  This also means that you can test ODBC
     Administrator configurations using the `iodbctest' command.
     `http://www.apple.com'.

   * `unixODBC' Driver Manager for Unix (`libodbc.so'). See
     `http://www.unixodbc.org', for more information. The `unixODBC'
     Driver Manager includes the Connector/ODBC driver 3.51 in the
     installation package, starting with version `unixODBC' 2.1.2.

   * `iODBC' ODBC Driver Manager for Unix (`libiodbc.so'), see
     `http://www.iodbc.org', for more information.


File: manual.info,  Node: connector-odbc-installation,  Next: connector-odbc-configuration,  Prev: connector-odbc-introduction,  Up: connector-odbc

20.1.3 Connector/ODBC Installation
----------------------------------

* Menu:

* connector-odbc-installation-binary-windows::  Installing Connector/ODBC from a Binary Distribution on Windows
* connector-odbc-installation-binary-unix::  Installing Connector/ODBC from a Binary Distribution on Unix
* connector-odbc-installation-binary-macosx::  Installing Connector/ODBC from a Binary Distribution on Mac OS X
* connector-odbc-installation-source-windows::  Installing Connector/ODBC from a Source Distribution on Windows
* connector-odbc-installation-source-unix::  Installing Connector/ODBC from a Source Distribution on Unix
* connector-odbc-installation-source-development::  Installing Connector/ODBC from the Development Source Tree

You can install the Connector/ODBC drivers using two different methods,
a binary installation and a source installation. The binary
installation is the easiest and most straightforward method of
installation. Using the source installation methods should only be
necessary on platforms where a binary installation package is not
available, or in situations where you want to customize or modify the
installation process or Connector/ODBC drivers before installation.

*Where to Get Connector/ODBC*

You can get a copy of the latest version of Connector/ODBC binaries and
sources from our Web site at
`http://dev.mysql.com/downloads/connector/odbc/'.

For more information about Connector/ODBC, visit
http://www.mysql.com/products/myodbc/.

For more information about licensing, visit
http://www.mysql.com/company/legal/licensing/.

*Supported Platforms*

Connector/ODBC can be used on all major platforms supported by MySQL.
You can install it on:

   * Windows 95, 98, Me, NT, 2000, XP, 2003, Vista and 7

   * All Unix-like Operating Systems, including: AIX, Amiga, BSDI, DEC,
     FreeBSD, HP-UX 10/11, Linux, NetBSD, OpenBSD, OS/2, SGI Irix,
     Solaris, SunOS, SCO OpenServer, SCO UnixWare, Tru64 Unix

   * Mac OS X and Mac OS X Server

Using a binary distribution offers the most straightforward method for
installing Connector/ODBC. If you want more control over the driver,
the installation location and or to customize elements of the driver
you will need to build and install from the source.

If a binary distribution is not available for a particular platform
build the driver from the original source code. You can contribute the
binaries you create to MySQL by sending a mail message to
<myodbc@lists.mysql.com>, so that it becomes available for other users.

*Note*:

On all non-Windows platforms except Mac OS X, the driver is built
against `unixODBC' and is expecting a 2-byte `SQLWCHAR', not 4 bytes as
`iODBC' is using. For this reason, the binaries are *only* compatible
with `unixODBC' and you will need to recompile the driver against
`iODBC' to use them together.  For further information see *Note
connector-odbc-driver-manager::.

For further instructions:

Platform               Binary                 Source
Windows                *Note Installation     *Note Build
                       Instructions:          Instructions:
                       connector-odbc-installation-binary-windows.connector-odbc-installation-source-windows.
Unix/Linux             *Note Installation     *Note Build
                       Instructions:          Instructions:
                       connector-odbc-installation-binary-unix.connector-odbc-installation-source-unix.
Mac OS X               *Note Installation     
                       Instructions:          
                       connector-odbc-installation-binary-macosx.


File: manual.info,  Node: connector-odbc-installation-binary-windows,  Next: connector-odbc-installation-binary-unix,  Prev: connector-odbc-installation,  Up: connector-odbc-installation

20.1.3.1 Installing Connector/ODBC from a Binary Distribution on Windows
........................................................................

* Menu:

* connector-odbc-installation-binary-windows-installer::  Installing the Windows Connector/ODBC Driver using an installer
* connector-odbc-installation-binary-windows-dll::  Installing the Windows Connector/ODBC Driver using the Zipped DLL package

Before installing the Connector/ODBC drivers on Windows you should
ensure that your Microsoft Data Access Components (MDAC) are up to
date. You can obtain the latest version from the Microsoft Data Access
and Storage (http://support.microsoft.com/kb/110093) Web site.

There are three available distribution types to use when installing for
Windows. The contents in each case are identical, it is only the
installation method which is different.

   * Zipped installer consists of a Zipped package containing a
     standalone installation application. To install from this package,
     you must unzip the installer, and then run the installation
     application. See *Note
     connector-odbc-installation-binary-windows-installer:: to complete
     the installation.

   * MSI installer, an installation file that can be used with the
     installer included in Windows 2000, Windows XP and Windows Server
     2003. See *Note
     connector-odbc-installation-binary-windows-installer:: to complete
     the installation.

   * Zipped DLL package, containing the DLL files that need must be
     manually installed. See *Note
     connector-odbc-installation-binary-windows-dll:: to complete the
     installation.

*Note*:

An OLEDB/ODBC driver for Windows 64-bit is available from Microsoft
Downloads
(http://www.microsoft.com/downloads/details.aspx?FamilyID=000364db-5e8b-44a8-b9be-ca44d18b059b&displaylang=en).


File: manual.info,  Node: connector-odbc-installation-binary-windows-installer,  Next: connector-odbc-installation-binary-windows-dll,  Prev: connector-odbc-installation-binary-windows,  Up: connector-odbc-installation-binary-windows

20.1.3.2 Installing the Windows Connector/ODBC Driver using an installer
........................................................................

The installer packages offer a very simple method for installing the
Connector/ODBC drivers. If you have downloaded the zipped installer
then you must extract the installer application. The basic installation
process is identical for both installers.

You should follow these steps to complete the installation:

  1. Double-click the standalone installer that you extracted, or the
     MSI file you downloaded.

  2. The MySQL Connector/ODBC 3.51 - Setup Wizard will start.  Click
     the `Next' button to begin the installation process.

     Connector/ODBC Windows Installer - Welcome

  3. You will need to choose the installation type. The Typical
     installation provides the standard files you will need to connect
     to a MySQL database using ODBC. The Complete option installs all
     the available files, including debug and utility components. It is
     recommended you choose one of these two options to complete the
     installation. If choose one of these methods, click `Next' and
     then proceed to step 5.

     You can also choose a Custom installation, which enables you to
     select the individual components to install. You have chosen this
     method, click `Next' and then proceed to step 4.

     Connector/ODBC Windows Installer - Choosing a Setup type welcome

  4. If you have chosen a custom installation, use the pop-ups to
     select which components to install and then click `Next' to
     install the necessary files.

     Connector/ODBC Windows Installer - Custom Installation welcome

  5. Once the files have copied to your machine, the installation is
     complete. Click `Finish' to exit the installer.

     Connector/ODBC Windows Installer - Completion welcome

Now the installation is complete, you can continue to configure your
ODBC connections using *Note connector-odbc-configuration::.


File: manual.info,  Node: connector-odbc-installation-binary-windows-dll,  Prev: connector-odbc-installation-binary-windows-installer,  Up: connector-odbc-installation-binary-windows

20.1.3.3 Installing the Windows Connector/ODBC Driver using the Zipped DLL package
..................................................................................

If you have downloaded the Zipped DLL package then you must install the
individual files required for Connector/ODBC operation manually. Once
you have unzipped the installation files, you can either perform this
operation by hand, executing each statement individually, or you can
use the included Batch file to perform an installation to the default
locations.

*Note*:

The following instructions will only work for 32-bit Windows systems.
If you have a 64-bit Windows system you are advised to use the MSI
installer, which will install both the 32-bit and 64-bit drivers to the
correct locations.

To install using the Batch file:

  1. Unzip the Connector/ODBC Zipped DLL package.

  2. Open a Command Prompt.

  3. Change to the directory created when you unzipped the
     Connector/ODBC Zipped DLL package.

  4. Run `Install.bat:'

          C:\> Install.bat

     This will copy the necessary files into the default location, and
     then register the Connector/ODBC driver with the Windows ODBC
     manager.

*Note*:

Changing or adding a new DSN (data source name) may be accomplished
using either the GUI, or from the command-line using `myodbc3i.exe'
with Connector/ODBC 3.51, or `myodbc-installer.exe' with Connector/ODBC
5.1.

To copy the files to an alternative location - for example, to run or
test different versions of the Connector/ODBC driver on the same
machine, then you must copy the files by hand. It is however not
recommended to install these files in a nonstandard location. To copy
the files by hand to the default installation location, use the
following steps:

  1. Unzip the Connector/ODBC Zipped DLL package.

  2. Open a Command Prompt.

  3. Change to the directory created when you unzipped the
     Connector/ODBC Zipped DLL package.

  4. Copy the library files to a suitable directory. The default is to
     copy them into the default Windows system directory
     `\Windows\System32':

          C:\> copy lib\myodbc3S.dll \Windows\System32
          C:\> copy lib\myodbc3S.lib \Windows\System32
          C:\> copy lib\myodbc3.dll \Windows\System32
          C:\> copy lib\myodbc3.lib \Windows\System32

  5. Copy the Connector/ODBC tools. These must be placed into a
     directory that is in the system `PATH'.  The default is to install
     these into the Windows system directory `\Windows\System32':

          C:\> copy bin\myodbc3i.exe \Windows\System32
          C:\> copy bin\myodbc3m.exe \Windows\System32
          C:\> copy bin\myodbc3c.exe \Windows\System32

  6. Optionally copy the help files. For these files to be accessible
     through the help system, they must be installed in the Windows
     system directory:

          C:\> copy doc\*.hlp \Windows\System32

  7. Finally, you must register the Connector/ODBC driver with the ODBC
     manager:

          C:\> myodbc3i -a -d -t"MySQL ODBC 3.51 Driver;\
            DRIVER=myodbc3.dll;SETUP=myodbc3S.dll"

     You must change the references to the DLL files and command
     location in the above statement if you have not installed these
     files into the default location.


File: manual.info,  Node: connector-odbc-installation-binary-unix,  Next: connector-odbc-installation-binary-macosx,  Prev: connector-odbc-installation-binary-windows,  Up: connector-odbc-installation

20.1.3.4 Installing Connector/ODBC from a Binary Distribution on Unix
.....................................................................

* Menu:

* connector-odbc-installation-binary-unix-tarball::  Installing Connector/ODBC from a Binary Tarball Distribution
* connector-odbc-installation-binary-unix-rpm::  Installing Connector/ODBC from an RPM Distribution

There are two methods available for installing Connector/ODBC on Unix
from a binary distribution. For most Unix environments you will need to
use the tarball distribution. For Linux systems, there is also an RPM
distribution available.

*Note*:

To install Connector/ODBC 5.1 on Unix you require unixODBC 2.2.12 or
later to be installed.


File: manual.info,  Node: connector-odbc-installation-binary-unix-tarball,  Next: connector-odbc-installation-binary-unix-rpm,  Prev: connector-odbc-installation-binary-unix,  Up: connector-odbc-installation-binary-unix

20.1.3.5 Installing Connector/ODBC from a Binary Tarball Distribution
.....................................................................

To install the driver from a tarball distribution (`.tar.gz' file),
download the latest version of the driver for your operating system and
follow these steps that demonstrate the process using the Linux version
of the tarball:

     shell> su root
     shell> gunzip mysql-connector-odbc-3.51.11-i686-pc-linux.tar.gz
     shell> tar xvf mysql-connector-odbc-3.51.11-i686-pc-linux.tar
     shell> cd mysql-connector-odbc-3.51.11-i686-pc-linux

Read the installation instructions in the `INSTALL' file and execute
these commands.

Then proceed on to *Note connector-odbc-configuration-dsn-unix::, to
configure the DSN for Connector/ODBC. For more information, refer to
the `INSTALL' file that comes with your distribution.


File: manual.info,  Node: connector-odbc-installation-binary-unix-rpm,  Prev: connector-odbc-installation-binary-unix-tarball,  Up: connector-odbc-installation-binary-unix

20.1.3.6 Installing Connector/ODBC from an RPM Distribution
...........................................................

To install or upgrade Connector/ODBC from an RPM distribution on Linux,
simply download the RPM distribution of the latest version of
Connector/ODBC and follow the instructions below.  Use `su root' to
become `root', then install the RPM file.

If you are installing for the first time:

     shell> su root
      shell> rpm -ivh mysql-connector-odbc-3.51.12.i386.rpm

If the driver exists, upgrade it like this:

     shell> su root
     shell> rpm -Uvh mysql-connector-odbc-3.51.12.i386.rpm

If there is any dependency error for MySQL client library,
`libmysqlclient', simply ignore it by supplying the `--nodeps' option,
and then make sure the MySQL client shared library is in the path or set
through `LD_LIBRARY_PATH'.

This installs the driver libraries and related documents to
`/usr/local/lib' and `/usr/share/doc/MyODBC', respectively.  Proceed
onto *Note connector-odbc-configuration-dsn-unix::.

To *uninstall* the driver, become `root' and execute an `rpm' command:

     shell> su root
     shell> rpm -e mysql-connector-odbc


File: manual.info,  Node: connector-odbc-installation-binary-macosx,  Next: connector-odbc-installation-source-windows,  Prev: connector-odbc-installation-binary-unix,  Up: connector-odbc-installation

20.1.3.7 Installing Connector/ODBC from a Binary Distribution on Mac OS X
.........................................................................

Mac OS X is based on the FreeBSD operating system, and you can normally
use the MySQL network port for connecting to MySQL servers on other
hosts. Installing the Connector/ODBC driver enables you to connect to
MySQL databases on any platform through the ODBC interface. You should
only need to install the Connector/ODBC driver when your application
requires an ODBC interface. Applications that require or can use ODBC
(and therefore the Connector/ODBC driver) include ColdFusion, Filemaker
Pro, 4th Dimension and many other applications.

Mac OS X includes its own ODBC manager, based on the `iODBC' manager.
Mac OS X includes an administration tool that provides easier
administration of ODBC drivers and configuration, updating the
underlying `iODBC' configuration files.

The method for installing Connector/ODBC on Mac OS X depends on the
version on Connector/ODBC you are using. For Connector/ODBC 3.51.14 and
later, the package is provided as a compressed tar archive that you
must manually install. For Connector/ODBC 3.51.13 and earlier the
software was provided on a compressed disk image (`.dmg') file and
included an installer.

In either case, the driver is designed to work with the iODBC driver
manager included with Mac OS X.

To install Connector/ODBC 3.51.14 and later:

  1. Download the installation file. Note that versions are available
     for both PowerPC and Intel platforms.

  2. Extract the archive:

          shell> tar zxf mysql-connector-odbc-3.51.16-osx10.4-x86-32bit.tar.gz

  3. The directory created will contain two subdirectories, `lib' and
     `bin'. You need to copy these to a suitable location such as
     `/usr/local':

          shell> cp bin/* /usr/local/bin
          shell> cp lib/* /usr/local/lib

  4. Finally, you must register the driver with iODBC using the
     `myodbc3i' tool you just installed:

          shell> myodbc3i -a -d -t"MySQL ODBC 3.51 Driver;Driver=/usr/local/lib/libmyodbc3.so;Setup=/usr/local/lib/libmyodbc3S.so"

You can verify the installed drivers either by using the ODBC
Administrator application or the `myodbc3i' utility:

     shell> myodbc3i -q -d

To install Connector/ODBC 3.51.13 and earlier, follow these steps:

  1. Download the file to your computer and double-click the downloaded
     image file.

  2. Within the disk image you will find an installer package (with the
     `.pkg' extension). Double-click on this file to start the Mac OS X
     installer.

  3. You will be presented with the installer welcome message.  Click
     the `Continue' button to begin the installation process.

     Connector/ODBC Mac OS X Installer - Installer welcome

  4. Please take the time to read the Important Information as it
     contains guidance on how to complete the installation process.
     Once you have read the notice and collected the necessary
     information, click `Continue'.

     Connector/ODBC Mac OS X Installer - Important Information

  5. Connector/ODBC drivers are made available under the GNU General
     Public License. Please read the license if you are not familiar
     with it before continuing installation. Click `Continue' to
     approve the license (you will be asked to confirm that decision)
     and continue the installation.

     Connector/ODBC Mac OS X Installer - License

  6. Choose a location to install the Connector/ODBC drivers and the
     ODBC Administrator application. You must install the files onto a
     drive with an operating system and you may be limited in the
     choices available. Select the drive you want to use, and then
     click `Continue'.

     Connector/ODBC Mac OS X Installer - Choosing a destination

  7. The installer will automatically select the files that need to be
     installed on your machine. Click `Install' to continue. The
     installer will copy the necessary files to your machine. A progress
     bar will be shown indicating the installation progress.

     Connector/ODBC Mac OS X Installer - Installation type

  8. When installation has been completed you will get a window like
     the one shown below. Click `Close' to close and quit the installer.

     Connector/ODBC Mac OS X Installer - Installation complete


File: manual.info,  Node: connector-odbc-installation-source-windows,  Next: connector-odbc-installation-source-unix,  Prev: connector-odbc-installation-binary-macosx,  Up: connector-odbc-installation

20.1.3.8 Installing Connector/ODBC from a Source Distribution on Windows
........................................................................

* Menu:

* connector-odbc-installation-source-windows-5-1-building::  Building Connector/ODBC 5.1
* connector-odbc-installation-source-windows-3-51-building::  Building Connector/ODBC 3.51

You only need to install Connector/ODBC from source on Windows to
change or modify the source or installation. If you are unsure whether
to install from source, please use the binary installation detailed in
*Note connector-odbc-installation-binary-windows::.

Installing Connector/ODBC from source on Windows requires a number of
different tools and packages:

   * MDAC, Microsoft Data Access SDK from
     `http://support.microsoft.com/kb/110093'.

   * Suitable C compiler, such as Microsoft Visual C++ or the C
     compiler included with Microsoft Visual Studio.

     Microsoft Visual Studio 7 and 8 are preferred, and well-tested.

   * Connector/ODBC 5.1: `CMake'.

     Connector/ODBC 3.51: A compatible `make' tool. Microsoft's `nmake'
     is used in the examples in this section.

   * MySQL client libraries and include files from MySQL 4.0.0 or
     higher. (Preferably MySQL 4.0.16 or higher). This is required
     because Connector/ODBC uses new calls and structures that exist
     only starting from this version of the library. To get the client
     libraries and include files, visit
     `http://dev.mysql.com/downloads/'.


File: manual.info,  Node: connector-odbc-installation-source-windows-5-1-building,  Next: connector-odbc-installation-source-windows-3-51-building,  Prev: connector-odbc-installation-source-windows,  Up: connector-odbc-installation-source-windows

20.1.3.9 Building Connector/ODBC 5.1
....................................

You need to have the environment variables set for the Visual Studio
toolchain. Visual Studio includes a batch file to set these for you,
and installs a Start menu shortcut that opens a command prompt with
these variables set.

You need to set `MYSQL_DIR' to the MySQL server installation path,
while using the short-style file names. For example:

     C:\> set MYSQL_DIR=C:\PROGRA~1\MySQL\MYSQLS~1.0

Build Connector/ODBC using the "cmake" command-line tool by executing
the following from the source root directory (in a command prompt
window):

     C:\> cmake -G "Visual Studio 8 2005"

This produces a project file that you can open with Visual Studio, or
build from the command line with either of the following commands:

     C:\> devenv.com MySQL_Connector_ODBC.sln /build Release
     C:\> devenv.com MySQL_Connector_ODBC.sln /build RelWithDebInfo

To compile the "Debug" build, you must set the cmake build type so that
the correct version of the MySQL client libraries are used:

     C:\> cmake -G "Visual Studio 8 2005" -DCMAKE_BUILD_TYPE=Debug
     C:\> devenv.com MySQL_Connector_ODBC.sln /build Debug

Upon completion, you will find the executables in the `bin/' and `lib/'
sub-directories.

See *Note connector-odbc-installation-binary-windows-dll:: to complete
the installation.


File: manual.info,  Node: connector-odbc-installation-source-windows-3-51-building,  Prev: connector-odbc-installation-source-windows-5-1-building,  Up: connector-odbc-installation-source-windows

20.1.3.10 Building Connector/ODBC 3.51
......................................

Connector/ODBC source distributions include `Makefiles' that require the
`nmake' or other `make' utility. In the distribution, you can find
`Makefile' for building the release version and `Makefile_debug' for
building debugging versions of the driver libraries and DLLs.

To build the driver, use this procedure:

  1. Download and extract the sources to a folder, then change
     directory into that folder. The following command assumes the
     folder is named `myodbc3-src':

          C:\> cd myodbc3-src

  2. Edit `Makefile' to specify the correct path for the MySQL client
     libraries and header files. Then use the following commands to
     build and install the release version:

          C:\> nmake -f Makefile
          C:\> nmake -f Makefile install

     `nmake -f Makefile' builds the release version of the driver and
     places the binaries in subdirectory called `Release'.

     `nmake -f Makefile install' installs (copies) the driver DLLs and
     libraries (`myodbc3.dll', `myodbc3.lib') to your system directory.

  3. To build the debug version, use `Makefile_Debug' rather than
     `Makefile', as shown below:

          C:\> nmake -f Makefile_debug
          C:\> nmake -f Makefile_debug install

  4. You can clean and rebuild the driver by using:

          C:\> nmake -f Makefile clean
          C:\> nmake -f Makefile install

*Note*:

   * Make sure to specify the correct MySQL client libraries and header
     files path in the Makefiles (set the `MYSQL_LIB_PATH' and
     `MYSQL_INCLUDE_PATH' variables). The default header file path is
     assumed to be `C:\mysql\include'. The default library path is
     assumed to be `C:\mysql\lib\opt' for release DLLs and
     `C:\mysql\lib\debug' for debug versions.

   * For the complete usage of `nmake', visit
     `http://msdn.microsoft.com/library/default.asp?url=/library/en-us/dv_vcce4/html/evgrfRunningNMAKE.asp'.

   * If you are using the Subversion tree for compiling, all
     Windows-specific `Makefiles' are named as `Win_Makefile*'.

After the driver libraries are copied/installed to the system
directory, you can test whether the libraries are properly built by
using the samples provided in the `samples' subdirectory:

     C:\> cd samples
     C:\> nmake -f Makefile all


File: manual.info,  Node: connector-odbc-installation-source-unix,  Next: connector-odbc-installation-source-development,  Prev: connector-odbc-installation-source-windows,  Up: connector-odbc-installation

20.1.3.11 Installing Connector/ODBC from a Source Distribution on Unix
......................................................................

* Menu:

* connector-odbc-installation-source-unix-cmake-options::  Typical `cmake' Options
* connector-odbc-installation-source-unix-configure-options::  Typical `configure' Options
* connector-odbc-installation-source-unix-otheroptions::  Additional configure Options
* connector-odbc-installation-source-unix-building::  Building and Compilation
* connector-odbc-installation-source-unix-shared-libraries::  Building Shared Libraries
* connector-odbc-installation-source-unix-installing::  Installing Driver Libraries
* connector-odbc-installation-source-unix-testing::  Testing Connector/ODBC on Unix
* connector-odbc-installation-source-unix-macosx::  Building Connector/ODBC from Source on Mac OS X
* connector-odbc-installation-source-unix-hpux::  Building Connector/ODBC from Source on HP-UX
* connector-odbc-installation-source-unix-aix::  Building Connector/ODBC from Source on AIX

*Note*:

As of Connector/5.1.9, the build system on Linux changed, and now uses
`CMake' instead of autoconf (`configure'). The manual refers to both
methods.

You need the following tools to build MySQL from source on Unix:

   * A working ANSI C++ compiler. `gcc' 2.95.2 or later, SGI C++, and
     SunPro C++ are some of the compilers that are known to work.

   * A good `make' program. GNU `make' is always recommended and is
     sometimes required.

   * `CMake', as of Connector/ODBC 5.1.9.

   * MySQL client libraries and include files from MySQL 4.0.0 or
     higher. (Preferably MySQL 4.0.16 or higher). This is required
     because Connector/ODBC uses new calls and structures that exist
     only starting from this version of the library. To get the client
     libraries and include files, visit
     `http://dev.mysql.com/downloads/'.

     If you have built your own MySQL server or client libraries from
     source using the GNU autotools, you must use the
     `--enable-thread-safe-client' option to `configure' when the
     libraries were built.  No special option is needed if you
     configure with `CMake'.

     You should also ensure that the `libmysqlclient' library were
     built and installed as a shared library.

   * A compatible ODBC manager must be installed. Connector/ODBC is
     known to work with the `iODBC' and `unixODBC' managers. See *Note
     connector-odbc-driver-manager::, for more information.

   * If you are using a character set that isn't compiled into the
     MySQL client library then you need to install the MySQL character
     definitions from the `charsets' directory into SHAREDIR (by
     default, `/usr/local/mysql/share/mysql/charsets').  These should
     be in place if you have installed the MySQL server on the same
     machine. See *Note charset::, for more information on character
     set support.

Once you have all the required files, unpack the source files to a
separate directory, you then have to run `configure' and build the
library using `make'.


File: manual.info,  Node: connector-odbc-installation-source-unix-cmake-options,  Next: connector-odbc-installation-source-unix-configure-options,  Prev: connector-odbc-installation-source-unix,  Up: connector-odbc-installation-source-unix

20.1.3.12 Typical `cmake' Options
.................................

`CMake' support on Unix exists as of Connector/ODBC 5.1.9.

`iODBC' is the default ODBC library used by Connector/ODBC.
Alternatively, `unixODBC' may be used by passing in the appropriate
option to `CMake'. For example:

     shell> cmake -G "Unix Makefiles" -DWITH_UNIXODBC=1

When you run `cmake', you might add options to the command line. Here
are some examples:

   * `-DODBC_INCLUDES=DIR_NAME'
     (http://dev.mysql.com/doc/refman/5.5/en/source-configuration-options.html#option_cmake_odbc_includes):
     Used when the ODBC include directory is not found within the
     system's PATH.

   * `-DODBC_LIB_DIR=DIR_NAME'
     (http://dev.mysql.com/doc/refman/5.5/en/source-configuration-options.html#option_cmake_odbc_lib_dir):
     Used when the ODBC library directory is not found within the
     system's PATH.

   * `-DWITH_UNIXODBC=1'
     (http://dev.mysql.com/doc/refman/5.5/en/source-configuration-options.html#option_cmake_with_unixodbc):
     Enables unixODBC support.


File: manual.info,  Node: connector-odbc-installation-source-unix-configure-options,  Next: connector-odbc-installation-source-unix-otheroptions,  Prev: connector-odbc-installation-source-unix-cmake-options,  Up: connector-odbc-installation-source-unix

20.1.3.13 Typical `configure' Options
.....................................

autoconf (`configure') is supported on Unix in Connector/ODBC 5.1.8 and
below.

The `configure' script gives you a great deal of control over how you
configure your Connector/ODBC build.  Typically you do this using
options on the `configure' command line. You can also affect
`configure' using certain environment variables. For a list of options
and environment variables supported by `configure', run this command:

     shell> ./configure --help

Some of the more commonly used `configure' options are described here:

  1. To compile Connector/ODBC, you need to supply the MySQL client
     include and library files path using the `--with-mysql-path=DIR'
     option, where DIR is the directory where MySQL is installed.

     MySQL compile options can be determined by running
     `DIR/bin/mysql_config'.

  2. Supply the standard header and library files path for your ODBC
     Driver Manager (`iODBC' or `unixODBC').

        * If you are using `iODBC' and `iODBC' is not installed in its
          default location (`/usr/local'), you might have to use the
          `--with-iodbc=DIR' option, where DIR is the directory where
          `iODBC' is installed.

          If the `iODBC' headers do not reside in `DIR/include', you
          can use the `--with-iodbc-includes=INCDIR' option to specify
          their location.

          The applies to libraries. If they are not in `DIR/lib', you
          can use the `--with-iodbc-libs=LIBDIR' option.

        * If you are using `unixODBC', use the `--with-unixODBC=DIR'
          option (case sensitive) to make `configure' look for
          `unixODBC' instead of `iODBC' by default, DIR is the
          directory where `unixODBC' is installed.

          If the `unixODBC' headers and libraries aren't located in
          `DIR/include' and `DIR/lib', use the
          `--with-unixODBC-includes=INCDIR' and
          `--with-unixODBC-libs=LIBDIR' options.

  3. You might specify an installation prefix other than `/usr/local'.
     For example, to install the Connector/ODBC drivers in
     `/usr/local/odbc/lib', use the `--prefix=/usr/local/odbc' option.

The final configuration command looks something like this:

     shell> ./configure --prefix=/usr/local \
              --with-iodbc=/usr/local \
              --with-mysql-path=/usr/local/mysql


File: manual.info,  Node: connector-odbc-installation-source-unix-otheroptions,  Next: connector-odbc-installation-source-unix-building,  Prev: connector-odbc-installation-source-unix-configure-options,  Up: connector-odbc-installation-source-unix

20.1.3.14 Additional configure Options
......................................

There are a number of other options that you need, or want, to set when
configuring the Connector/ODBC driver before it is built.

   * To link the driver with MySQL thread safe client libraries
     `libmysqlclient_r.so' or `libmysqlclient_r.a', you must specify
     the following `configure' option:

          --enable-thread-safe

     and can be disabled (default) using

          --disable-thread-safe

     This option enables the building of the driver thread-safe library
     `libmyodbc3_r.so' from by linking with MySQL thread-safe client
     library `libmysqlclient_r.so' (The extensions are OS dependent).

     If the compilation with the thread-safe option fails, it may be
     because the correct thread-libraries on the system could not be
     located. You should set the value of `LIBS' to point to the
     correct thread library for your system.

          LIBS="-lpthread" ./configure ..

   * You can enable or disable the shared and static versions of
     Connector/ODBC using these options:

          --enable-shared[=yes/no]
          --disable-shared
          --enable-static[=yes/no]
          --disable-static

   * By default, all the binary distributions are built as nondebugging
     versions (configured with `--without-debug').

     To enable debugging information, build the driver from a source
     distribution with the proper configuration option to enable
     debugging support. See *Note source-configuration-options::.

   * This option is available only for source trees that have been
     obtained from the Subversion repository. This option does not
     apply to the packaged source distributions.

     By default, the driver is built with the `--without-docs' option.
     If you would like the documentation to be built, then execute
     `configure' with:

          --with-docs


File: manual.info,  Node: connector-odbc-installation-source-unix-building,  Next: connector-odbc-installation-source-unix-shared-libraries,  Prev: connector-odbc-installation-source-unix-otheroptions,  Up: connector-odbc-installation-source-unix

20.1.3.15 Building and Compilation
..................................

To build the driver libraries, you have to just execute `make'.

     shell> make

If any errors occur, correct them and continue the build process. If
you aren't able to build, then send a detailed email to
<myodbc@lists.mysql.com> for further assistance.


File: manual.info,  Node: connector-odbc-installation-source-unix-shared-libraries,  Next: connector-odbc-installation-source-unix-installing,  Prev: connector-odbc-installation-source-unix-building,  Up: connector-odbc-installation-source-unix

20.1.3.16 Building Shared Libraries
...................................

On most platforms, MySQL does not build or support `.so' (shared)
client libraries by default.  This is based on our experience of
problems when building shared libraries.

In cases like this, you have to download the MySQL distribution and
configure it with these options:

     --without-server --enable-shared

To build shared driver libraries, you must specify the
`--enable-shared' option for `configure'. By default, `configure' does
not enable this option.

If you have configured with the `--disable-shared' option, you can
build the `.so' file from the static libraries using the following
commands:

     shell> cd mysql-connector-odbc-3.51.01
     shell> make
     shell> cd driver
     shell> CC=/usr/bin/gcc \
               $CC -bundle -flat_namespace -undefined error \
               -o .libs/libmyodbc3-3.51.01.so \
               catalog.o connect.o cursor.o dll.o error.o execute.o \
               handle.o info.o misc.o myodbc3.o options.o prepare.o \
               results.o transact.o utility.o \
               -L/usr/local/mysql/lib/mysql/ \
               -L/usr/local/iodbc/lib/ \
               -lz -lc -lmysqlclient -liodbcinst

Make sure to change `-liodbcinst' to `-lodbcinst' if you are using
`unixODBC' instead of `iODBC', and configure the library paths
accordingly.

This builds and places the `libmyodbc3-3.51.01.so' file in the `.libs'
directory. Copy this file to the Connector/ODBC library installation
directory (`/usr/local/lib' (or the `lib' directory under the
installation directory that you supplied with the `--prefix').

     shell> cd .libs
     shell> cp libmyodbc3-3.51.01.so /usr/local/lib
     shell> cd /usr/local/lib
     shell> ln -s libmyodbc3-3.51.01.so libmyodbc3.so

To build the thread-safe driver library:

     shell> CC=/usr/bin/gcc \
               $CC -bundle -flat_namespace -undefined error
               -o .libs/libmyodbc3_r-3.51.01.so
               catalog.o connect.o cursor.o dll.o error.o execute.o
               handle.o info.o misc.o myodbc3.o options.o prepare.o
               results.o transact.o utility.o
               -L/usr/local/mysql/lib/mysql/
               -L/usr/local/iodbc/lib/
               -lz -lc -lmysqlclient_r -liodbcinst


File: manual.info,  Node: connector-odbc-installation-source-unix-installing,  Next: connector-odbc-installation-source-unix-testing,  Prev: connector-odbc-installation-source-unix-shared-libraries,  Up: connector-odbc-installation-source-unix

20.1.3.17 Installing Driver Libraries
.....................................

To install the driver libraries, execute the following command:

     shell> make install

That command installs one of the following sets of libraries:

For Connector/ODBC 3.51:

   * `libmyodbc3.so'

   * `libmyodbc3-3.51.01.so', where 3.51.01 is the version of the driver

   * `libmyodbc3.a'

For thread-safe Connector/ODBC 3.51:

   * `libmyodbc3_r.so'

   * `libmyodbc3-3_r.51.01.so'

   * `libmyodbc3_r.a'

For more information on build process, refer to the `INSTALL' file that
comes with the source distribution. Note that if you are trying to use
the `make' from Sun, you may end up with errors.  On the other hand,
GNU `gmake' should work fine on all platforms.


File: manual.info,  Node: connector-odbc-installation-source-unix-testing,  Next: connector-odbc-installation-source-unix-macosx,  Prev: connector-odbc-installation-source-unix-installing,  Up: connector-odbc-installation-source-unix

20.1.3.18 Testing Connector/ODBC on Unix
........................................

To run the basic samples provided in the distribution with the
libraries that you built, use the following command:

     shell> make test

Before running the tests, create the DSN 'myodbc3' in `odbc.ini' and
set the environment variable `ODBCINI' to the correct `odbc.ini' file;
and MySQL server is running. You can find a sample `odbc.ini' with the
driver distribution.

You can even modify the `samples/run-samples' script to pass the
desired DSN, UID, and PASSWORD values as the command-line arguments to
each sample.


File: manual.info,  Node: connector-odbc-installation-source-unix-macosx,  Next: connector-odbc-installation-source-unix-hpux,  Prev: connector-odbc-installation-source-unix-testing,  Up: connector-odbc-installation-source-unix

20.1.3.19 Building Connector/ODBC from Source on Mac OS X
.........................................................

To build the driver on Mac OS X (Darwin), make use of the following
`configure' example:

     shell> ./configure --prefix=/usr/local
               --with-unixODBC=/usr/local
               --with-mysql-path=/usr/local/mysql
               --disable-shared
               --enable-gui=no
               --host=powerpc-apple

The command assumes that the `unixODBC' and MySQL are installed in the
default locations. If not, configure accordingly.

On Mac OS X, `--enable-shared' builds `.dylib' files by default. You
can build `.so' files like this:

     shell> make
     shell> cd driver
     shell> CC=/usr/bin/gcc \
               $CC -bundle -flat_namespace -undefined error
               -o .libs/libmyodbc3-3.51.01.so *.o
               -L/usr/local/mysql/lib/
               -L/usr/local/iodbc/lib
               -liodbcinst -lmysqlclient -lz -lc

To build the thread-safe driver library:

     shell> CC=/usr/bin/gcc \
               $CC -bundle -flat_namespace -undefined error
               -o .libs/libmyodbc3-3.51.01.so *.o
               -L/usr/local/mysql/lib/
               -L/usr/local/iodbc/lib
               -liodbcinst -lmysqlclienti_r -lz -lc -lpthread

Make sure to change the `-liodbcinst' to `-lodbcinst' in case of using
`unixODBC' instead of `iODBC' and configure the libraries path
accordingly.

In Apple's version of GCC, both `cc' and `gcc' are actually symbolic
links to `gcc3'.

Copy this library to the `$prefix/lib' directory and symlink to
`libmyodbc3.so'.

You can cross-check the output shared-library properties using this
command:

     shell> otool -LD .libs/libmyodbc3-3.51.01.so


File: manual.info,  Node: connector-odbc-installation-source-unix-hpux,  Next: connector-odbc-installation-source-unix-aix,  Prev: connector-odbc-installation-source-unix-macosx,  Up: connector-odbc-installation-source-unix

20.1.3.20 Building Connector/ODBC from Source on HP-UX
......................................................

To build the driver on HP-UX 10.x or 11.x, make use of the following
`configure' example:

If using `cc':

     shell> CC="cc" \
               CFLAGS="+z" \
               LDFLAGS="-Wl,+b:-Wl,+s" \
               ./configure --prefix=/usr/local
               --with-unixodbc=/usr/local
               --with-mysql-path=/usr/local/mysql/lib/mysql
               --enable-shared
               --enable-thread-safe

If using `gcc':

     shell> CC="gcc" \
               LDFLAGS="-Wl,+b:-Wl,+s" \
               ./configure --prefix=/usr/local
               --with-unixodbc=/usr/local
               --with-mysql-path=/usr/local/mysql
               --enable-shared
               --enable-thread-safe

Once the driver is built, cross-check its attributes using `chatr
.libs/libmyodbc3.sl' to determine whether you need to have set the
MySQL client library path using the `SHLIB_PATH' environment variable.
For static versions, ignore all shared-library options and run
`configure' with the `--disable-shared' option.


File: manual.info,  Node: connector-odbc-installation-source-unix-aix,  Prev: connector-odbc-installation-source-unix-hpux,  Up: connector-odbc-installation-source-unix

20.1.3.21 Building Connector/ODBC from Source on AIX
....................................................

To build the driver on AIX, make use of the following `configure'
example:

     shell> ./configure --prefix=/usr/local
               --with-unixodbc=/usr/local
               --with-mysql-path=/usr/local/mysql
               --disable-shared
               --enable-thread-safe

*Note*:

For more information about how to build and set up the static and
shared libraries across the different platforms refer to ' Using static
and shared libraries across platforms
(http://www.fortran-2000.com/ArnaudRecipes/sharedlib.html)'.


File: manual.info,  Node: connector-odbc-installation-source-development,  Prev: connector-odbc-installation-source-unix,  Up: connector-odbc-installation

20.1.3.22 Installing Connector/ODBC from the Development Source Tree
....................................................................

*Caution*:

You should read this section only if you are interested in helping us
test our new code. To just get MySQL Connector/ODBC up and running on
your system, use a standard release distribution.

To obtain the most recent development source tree, you first need to
download and install Bazaar. You can obtain Bazaar from the Bazaar VCS
Web site (http://bazaar-vcs.org). Bazaar is supported by any platform
that supports Python, and is therefore compatible with any Linux, Unix,
Windows or Mac OS X host. Instructions for downloading and installing
Bazaar on the different platforms are available on the Bazaar Web site.

To build from the source trees, you need the following tools:

   * autoconf 2.52 (or newer)

   * automake 1.4 (or newer)

   * libtool 1.4 (or newer)

   * m4

The most recent development source tree is available from our public
Subversion trees at `http://dev.mysql.com/tech-resources/sources.html'.

To check out out the Connector/ODBC sources, change to the directory
where you want the copy of the Connector/ODBC tree to be stored, then
use the following command:

     shell> bzr branch lp:myodbc

You should now have a copy of the entire Connector/ODBC source tree in
the directory `connector-odbc3'. To build from this source tree on Unix
or Linux follow these steps:

     shell> cd myodbc
     shell> aclocal
     shell> autoheader
     shell> libtoolize -c -f
     shell> autoconf
     shell> automake;
     shell> ./configure  # Add your favorite options here
     shell> make

For more information on how to build, refer to the `INSTALL' file
located in the same directory.  For more information on options to
`configure', see *Note
connector-odbc-installation-source-unix-configure-options::

When the build is done, run `make install' to install the
Connector/ODBC 3.51 driver on your system.

If you have gotten to the `make' stage and the distribution does not
compile, please report it to <myodbc@lists.mysql.com>.

On Windows, make use of Windows Makefiles `WIN-Makefile' and
`WIN-Makefile_debug' in building the driver.  For more information, see
*Note connector-odbc-installation-source-windows::.

After the initial checkout operation to get the source tree, you should
run `bzr pull' periodically to update your source according to the
latest version.


File: manual.info,  Node: connector-odbc-configuration,  Next: connector-odbc-examples,  Prev: connector-odbc-installation,  Up: connector-odbc

20.1.4 Connector/ODBC Configuration
-----------------------------------

* Menu:

* connector-odbc-configuration-dsn::  Data Source Names
* connector-odbc-configuration-connection-parameters::  Connector/ODBC Connection Parameters
* connector-odbc-configuration-dsn-windows::  Configuring a Connector/ODBC DSN on Windows
* connector-odbc-configuration-dsn-macosx::  Configuring a Connector/ODBC DSN on Mac OS X
* connector-odbc-configuration-dsn-unix::  Configuring a Connector/ODBC DSN on Unix
* connector-odbc-configuration-connection-without-dsn::  Connecting Without a Predefined DSN
* connector-odbc-configuration-connection-pooling::  ODBC Connection Pooling
* connector-odbc-configuration-trace::  Getting an ODBC Trace File

Before you connect to a MySQL database using the Connector/ODBC driver
you must configure an ODBC _Data Source Name_. The DSN associates the
various configuration parameters required to communicate with a
database to a specific name. You use the DSN in an application to
communicate with the database, rather than specifying individual
parameters within the application itself. DSN information can be user
specific, system specific, or provided in a special file. ODBC data
source names are configured in different ways, depending on your
platform and ODBC driver.


File: manual.info,  Node: connector-odbc-configuration-dsn,  Next: connector-odbc-configuration-connection-parameters,  Prev: connector-odbc-configuration,  Up: connector-odbc-configuration

20.1.4.1 Data Source Names
..........................

A Data Source Name associates the configuration parameters for
communicating with a specific database. Generally a DSN consists of the
following parameters:

   * Name

   * Host Name

   * Database Name

   * Login

   * Password

In addition, different ODBC drivers, including Connector/ODBC, may
accept additional driver-specific options and parameters.

There are three types of DSN:

   * A _System DSN_ is a global DSN definition that is available to any
     user and application on a particular system. A System DSN can
     normally only be configured by a systems administrator, or by a
     user who has specific permissions that let them create System DSNs.

   * A _User DSN_ is specific to an individual user, and can be used to
     store database connectivity information that the user regularly
     uses.

   * A _File DSN_ uses a simple file to define the DSN configuration.
     File DSNs can be shared between users and machines and are
     therefore more practical when installing or deploying DSN
     information as part of an application across many machines.

DSN information is stored in different locations depending on your
platform and environment.


File: manual.info,  Node: connector-odbc-configuration-connection-parameters,  Next: connector-odbc-configuration-dsn-windows,  Prev: connector-odbc-configuration-dsn,  Up: connector-odbc-configuration

20.1.4.2 Connector/ODBC Connection Parameters
.............................................

You can specify the parameters in the following tables for
Connector/ODBC when configuring a DSN. Users on Windows can use the
Options and Advanced panels when configuring a DSN to set these
parameters; see the table for information on which options relate to
which fields and check boxes. On Unix and Mac OS X, use the parameter
name and value as the keyword/value pair in the DSN configuration.
Alternatively, you can set these parameters within the
`InConnectionString' argument in the `SQLDriverConnect()' call.

Parameter   Default Value  Comment
`user'      ODBC           The user name used to connect to MySQL.
`uid'       ODBC           Synonymous with `user'. Added in 3.51.16.
`server'    `localhost'    The host name of the MySQL server.
`database'                 The default database.
`option'    0              Options that specify how Connector/ODBC should
                           work. See below.
`port'      3306           The TCP/IP port to use if `server' is not
                           `localhost'.
`initstmt'                 Initial statement. A statement to execute when
                           connecting to MySQL. In version 3.51 the
                           parameter is called `stmt'. Note, the driver
                           supports the initial statement being executed
                           only at the time of the initial connection.
`password'                 The password for the `user' account on
                           `server'.
`pwd'                      Synonymous with `password'. Added in 3.51.16.
`socket'                   The Unix socket file or Windows named pipe to
                           connect to if `server' is `localhost'.
`sslca'                    The path to a file with a list of trust SSL
                           CAs. Added in 3.51.16.
`sslcapath'                The path to a directory that contains trusted
                           SSL CA certificates in PEM format. Added in
                           3.51.16.
`sslcert'                  The name of the SSL certificate file to use
                           for establishing a secure connection. Added in
                           3.51.16.
`sslcipher'                A list of permissible ciphers to use for SSL
                           encryption. The cipher list has the same
                           format as the `openssl ciphers' command Added
                           in 3.51.16.
`sslkey'                   The name of the SSL key file to use for
                           establishing a secure connection. Added in
                           3.51.16.
`charset'                  The character set to use for the connection.
                           Added in 3.51.17.
`sslverify'                If set to 1, the SSL certificate will be
                           verified when used with the MySQL connection.
                           If not set, then the default behavior is to
                           ignore SSL certificate verification.
`readtimeout'               The timeout in seconds for attempts to read
                           from the server. Each attempt uses this
                           timeout value and there are retries if
                           necessary, so the total effective timeout
                           value is three times the option value. You can
                           set the value so that a lost connection can be
                           detected earlier than the TCP/IP
                           `Close_Wait_Timeout' value of 10 minutes. This
                           option works only for TCP/IP connections, and
                           only for Windows prior to MySQL 5.1.12.
                           Corresponds to the `MYSQL_OPT_READ_TIMEOUT'
                           option of the MySQL Client Library. This
                           option was added in Connector/ODBC 3.51.27.
`writetimeout'               The timeout in seconds for attempts to write
                           to the server. Each attempt uses this timeout
                           value and there are `net_retry_count' retries
                           if necessary, so the total effective timeout
                           value is `net_retry_count' times the option
                           value. This option works only for TCP/IP
                           connections, and only for Windows prior to
                           MySQL 5.1.12. Corresponds to the
                           `MYSQL_OPT_WRITE_TIMEOUT' option of the MySQL
                           Client Library. This option was added in
                           Connector/ODBC 3.51.27.
`interactive'               Enables the `CLIENT_INTERACTIVE' connection
                           option of `mysql_real_connect'.

*Note*:

The SSL configuration parameters can also be automatically loaded from
a `my.ini' or `my.cnf' file.

The `option' argument is used to tell Connector/ODBC that the client
isn't 100% ODBC compliant. On Windows, you normally select options by
toggling the check boxes in the connection screen, but you can also
select them in the `option' argument. The following options are listed
in the order in which they appear in the Connector/ODBC connect screen.

Flagname       GUI Option     Description
`FLAG_FIELD_LENGTH'Do not         The client cannot handle that
               Optimize       Connector/ODBC returns the real width of a
               Column Width   column. This option was removed in 3.51.18.
`FLAG_FOUND_ROWS'Return         The client cannot handle that MySQL
               Matching Rows  returns the true value of affected rows.
                              If this flag is set, MySQL returns `found
                              rows' instead. You must have MySQL 3.21.14
                              or newer to get this to work.
`FLAG_DEBUG'   Trace Driver   Make a debug log in `C:\myodbc.log' on
               Calls To       Windows, or `/tmp/myodbc.log' on Unix
               myodbc.log     variants.  This option was removed in
                              Connector/ODBC 3.51.18.
`FLAG_BIG_PACKETS'Allow Big      Do not set any packet limit for results
               Results        and bind parameters. Without this option,
                              parameter binding will be truncated to 255
                              characters.
`FLAG_NO_PROMPT'Do not Prompt  Do not prompt for questions even if driver
               Upon Connect   would like to prompt.
`FLAG_DYNAMIC_CURSOR'Enable         Enable or disable the dynamic cursor
               Dynamic Cursor support.
`FLAG_NO_SCHEMA'Ignore # in    Ignore use of database name in
               Table Name     DB_NAME.TBL_NAME.COL_NAME.
`FLAG_NO_DEFAULT_CURSOR'User Manager   Force use of ODBC manager cursors
               Cursors        (experimental).
`FLAG_NO_LOCALE'Do not Use     Disable the use of extended fetch
               Set Locale     (experimental).
`FLAG_PAD_SPACE'Pad Char To    Pad *Note `CHAR': char. columns to full
               Full Length    column length.
`FLAG_FULL_COLUMN_NAMES'Return Table   `SQLDescribeCol()' returns fully qualified
               Names for      column names.
               SQLDescribeCol 
`FLAG_COMPRESSED_PROTO'Use            Use the compressed client/server protocol.
               Compressed     
               Protocol       
`FLAG_IGNORE_SPACE'Ignore Space   Tell server to ignore space after function
               After          name and before ``('' (needed by
               Function Names PowerBuilder). This makes all function
                              names keywords.
`FLAG_NAMED_PIPE'Force Use of   Connect with named pipes to a *Note
               Named Pipes    `mysqld': mysqld. server running on NT.
`FLAG_NO_BIGINT'Change BIGINT  Change *Note `BIGINT': numeric-types.
               Columns to Int columns to *Note `INT': numeric-types.
                              columns (some applications cannot handle
                              *Note `BIGINT': numeric-types.).
`FLAG_NO_CATALOG'No Catalog     Forces results from the catalog functions,
                              such as `SQLTables', to always return
                              `NULL' and the driver to report that
                              catalogs are not supported.
`FLAG_USE_MYCNF'Read Options   Read parameters from the `[client]' and
               From `my.cnf'  `[odbc]' groups from `my.cnf'.
`FLAG_SAFE'    Safe           Add some extra safety checks.
`FLAG_NO_TRANSACTIONS'Disable        Disable transactions.
               transactions   
`FLAG_LOG_QUERY'Save queries   Enable query logging to
               to             `c:\myodbc.sql'(`/tmp/myodbc.sql') file.
               `myodbc.sql'   (Enabled only in debug mode.)
`FLAG_NO_CACHE'Do not Cache   Do not cache the results locally in the
               Result         driver, instead read from server (*Note
               (forward only  `mysql_use_result()': mysql-use-result.).
               cursors)       This works only for forward-only cursors.
                              This option is very important in dealing
                              with large tables when you do not want the
                              driver to cache the entire result set.
`FLAG_FORWARD_CURSOR'Force Use Of   Force the use of `Forward-only' cursor
               Forward Only   type. In case of applications setting the
               Cursors        default static/dynamic cursor type, and
                              one wants the driver to use noncache result
                              sets, then this option ensures the
                              forward-only cursor behavior.
`FLAG_AUTO_RECONNECT'Enable         Enables auto-reconnection functionality.
               auto-reconnect.You should not use this option with
                              transactions, since a auto reconnection
                              during a incomplete transaction may cause
                              corruption. Note that an auto-reconnected
                              connection will not inherit the same
                              settings and environment as the original.
                              This option was added in Connector/ODBC
                              3.51.13.
`FLAG_AUTO_IS_NULL'Flag Auto Is   When `FLAG_AUTO_IS_NULL' is set, the
               Null           driver does not change the default value of
                              `sql_auto_is_null', leaving it at 1, so
                              you get the MySQL default, not the SQL
                              standard behavior.
                              
                              When `FLAG_AUTO_IS_NULL' is not set, the
                              driver changes the default value of
                              `SQL_AUTO_IS_NULL' to 0 after connecting,
                              so you get the SQL standard, not the MySQL
                              default behavior.
                              
                              Thus, omitting the flag disables the
                              compatibility option and forces SQL
                              standard behavior.
                              
                              See `IS NULL'. This option was added in
                              Connector/ODBC 3.51.13.
`FLAG_ZERO_DATE_TO_MIN'Return         Translates zero dates (`XXXX-00-00') into
               SQL_NULL_DATA  the minimum date values supported by ODBC,
               for zero date  `XXXX-01-01'. This resolves an issue where
                              some statements will not work because the
                              date returned and the minimum ODBC date
                              value are incompatible. This option was
                              added in Connector/ODBC 3.51.17.
`FLAG_MIN_DATE_TO_ZERO'Bind minimal   Translates the minimum ODBC date value
               date as zero   (`XXXX-01-01') to the zero date format
               date           supported by MySQL (`XXXX-00-00'). This
                              resolves an issue where some statements
                              will not work because the date returned
                              and the minimum ODBC date value are
                              incompatible. This option was added in
                              Connector/ODBC 3.51.17.
`FLAG_MULTI_STATEMENTS'Allow          Enables support for batched statements.
               multiple       This option was added in Connector/ODBC
               statements     3.51.18.
`FLAG_COLUMN_SIZE_S32'Limit column   Limits the column size to a signed 32-bit
               size to        value to prevent problems with larger
               32-bit value   column sizes in applications that do not
                              support them. This option is automatically
                              enabled when working with ADO
                              applications. This option was added in
                              Connector/ODBC 3.51.22.
`FLAG_NO_BINARY_RESULT'Always handle  When set this option disables charset 63
               binary         for columns with an empty `org_table'.
               function       This option was added in Connector/ODBC
               results as     3.51.26.
               character data 
`FLAG_NO_INFORMATION_SCHEMA'               Tells catalog functions not to use
                              `INFORMATION_SCHEMA', but rather use
                              legacy algorithms. The trade-off here is
                              usually speed for information quality.
                              Using `INFORMATION_SCHEMA' is often slow,
                              but the information obtained is more
                              complete.
`FLAG_DFLT_BIGINT_BIND_STR'               Causes `BIGINT' parameters to be bound as
                              strings.  Microsoft Access treats `BIGINT'
                              as a string on linked tables. The value is
                              read correctly, but bound as a string.
                              This option is used automatically if the
                              driver is used by Microsoft Access.

To select multiple options, add together their values.

*Note*:

From version of MySQL Connector/ODBC 5.1.6 onwards, it is possible to
use the flag name directly as a parameter in the connection string, by
using the flag name without the FLAG_ prefix. So, in addition to using
the `options' parameter with various flags set, it is now possible to
use the flags directly as parameters. For example, `FIELD_LENGTH',
`FOUND_ROWS' and `DEBUG' could all be used as parameters.

The following table shows some recommended `option' values for various
configurations.

Configuration                                                 Option
                                                              Value
Microsoft Access, Visual Basic                                3
Driver trace generation (Debug mode)                          4
Microsoft Access (with improved DELETE queries)               35
Large tables with too many rows                               2049
Sybase PowerBuilder                                           135168
Query log generation (Debug mode)                             524288
Generate driver trace as well as query log (Debug mode)       524292
Large tables with no-cache results                            3145731


File: manual.info,  Node: connector-odbc-configuration-dsn-windows,  Next: connector-odbc-configuration-dsn-macosx,  Prev: connector-odbc-configuration-connection-parameters,  Up: connector-odbc-configuration

20.1.4.3 Configuring a Connector/ODBC DSN on Windows
....................................................

* Menu:

* connector-odbc-configuration-dsn-windows-3-51::  Configuring a Connector/ODBC 3.51 DSN on Windows
* connector-odbc-configuration-dsn-windows-3-51-command-line::  Configuring a Connector/ODBC 3.51 DSN on Windows, using the command-line
* connector-odbc-configuration-dsn-windows-5-1::  Configuring a Connector/ODBC 5.1 DSN on Windows
* connector-odbc-configuration-dsn-windows-5-1-command-line::  Configuring a Connector/ODBC 5.1 DSN on Windows, using the command-line
* connector-odbc-configuration-dsn-windows-problems::  Errors and Debugging

The `ODBC Data Source Administrator' within Windows enables you to
create DSNs, check driver installation and configure ODBC systems such
as tracing (used for debugging) and connection pooling.

Different editions and versions of Windows store the `ODBC Data Source
Administrator' in different locations depending on the version of
Windows that you are using.

To open the `ODBC Data Source Administrator' in Windows Server 2003:

*Tip*:

Because it is possible to create DSN using either the 32-bit or 64-bit
driver, but using the same DNS identifier, it is advisable to include
the driver being used within the DSN identifier. This will help you to
identify the DSN when using it from applications such as Excel that are
only compatible with the 32-bit driver. For example, you might add
`Using32bitCODBC' to the DSN identifier for the 32-bit interface and
`Using64bitCODBC' for those using the 64-bit Connector/ODBC driver.

  1. On the `Start' menu, choose `Administrative Tools', and then click
     `Data Sources (ODBC)'.

To open the `ODBC Data Source Administrator' in Windows 2000 Server or
Windows 2000 Professional:

  1. On the `Start' menu, choose `Settings', and then click `Control
     Panel'.

  2. In `Control Panel', click `Administrative Tools'.

  3. In `Administrative Tools', click `Data Sources (ODBC)'.

To open the `ODBC Data Source Administrator' on Windows XP:

  1. On the `Start' menu, click `Control Panel'.

  2. In the `Control Panel' when in `Category View' click `Performance
     and Maintenance' and then click `Administrative Tools.'. If you
     are viewing the `Control Panel' in `Classic View', click
     `Administrative Tools'.

  3. In `Administrative Tools', click `Data Sources (ODBC)'.

Irrespective of your Windows version, you should be presented the `ODBC
Data Source Administrator' window:

`ODBC Data Source Administrator' Dialog

Within Windows XP, you can add the `Administrative Tools' folder to
your `Start' menu to make it easier to locate the ODBC Data Source
Administrator.  To do this:

  1. Right-click the `Start' menu.

  2. Select `Properties'.

  3. Click `Customize...'.

  4. Select the `Advanced' tab.

  5. Within `Start menu items', within the `System Administrative
     Tools' section, select `Display on the All Programs menu'.

Within both Windows Server 2003 and Windows XP, consider permanently
adding the `ODBC Data Source Administrator' to your `Start' menu. To do
this, locate the `Data Sources (ODBC)' icon using the methods shown,
then right-click on the icon and then choose `Pin to Start Menu'.

The interfaces for the 3.51 and 5.1 versions of the Connector/ODBC
driver are different, although the fields and information that you need
to enter remain the same.

To configure a DSN using Connector/ODBC 3.51.x or Connector/ODBC 5.1.0,
see *Note connector-odbc-configuration-dsn-windows-3-51::.

To configure a DSN using Connector/ODBC 5.1.1 or later, see *Note
connector-odbc-configuration-dsn-windows-5-1::.


File: manual.info,  Node: connector-odbc-configuration-dsn-windows-3-51,  Next: connector-odbc-configuration-dsn-windows-3-51-command-line,  Prev: connector-odbc-configuration-dsn-windows,  Up: connector-odbc-configuration-dsn-windows

20.1.4.4 Configuring a Connector/ODBC 3.51 DSN on Windows
.........................................................

To add or configure a Connector/ODBC 3.51 DSN on Windows, use either
the command-line, or the `ODBC Data Source Administrator' GUI.

  1. Open the `ODBC Data Source Administrator'.

  2. To create a System DSN (which will be available to all users) ,
     select the `System DSN' tab. To create a User DSN, which will be
     unique only to the current user, click the `Add...' button.

  3. You will need to select the ODBC driver for this DSN.

     `MySQL ODBC Driver Selection' Dialog

     Select `MySQL ODBC 3.51 Driver', then click `Finish'.

  4. You now need to configure the specific fields for the DSN you are
     creating through the `Add Data Source Name' dialog.

     `Add Data Source Name' Dialog for Connector/ODBC 3.51.x

     In the `Data Source Name' box, enter the name of the data source
     to access. It can be any valid name that you choose.

  5. In the `Description' box, enter some text to help identify the
     connection.

  6. In the `Server' field, enter the name of the MySQL server host to
     access. By default, it is `localhost'.

  7. In the `User' field, enter the user name to use for this
     connection.

  8. In the `Password' field, enter the corresponding password for this
     connection.

  9. The `Database' pop-up should automatically populate with the list
     of databases that the user has permissions to access.

 10. Click `OK' to save the DSN.

A completed DSN configuration may look like this:

Sample`MySQL ODBC DSN Configuration' Dialog

You can verify the connection using the parameters you have entered by
clicking the `Test' button. If the connection could be made
successfully, you will be notified with a `Success; connection was
made!' dialog.

If the connection failed, you can obtain more information on the test
and why it may have failed by clicking the `Diagnostics...' button to
show additional error messages.

You can configure a number of options for a specific DSN by using
either the `Connect Options' or `Advanced' tabs in the DSN configuration
dialog.

Connector/ODBC Connect Options Dialog

The three options you can configure are:

   * `Port' sets the TCP/IP port number to use when communicating with
     MySQL. Communication with MySQL uses port 3306 by default. If your
     server is configured to use a different TCP/IP port, you must
     specify that port number here.

   * `Socket' sets the name or location of a specific socket or Windows
     pipe to use when communicating with MySQL.

   * `Initial Statement' defines an SQL statement that will be executed
     when the connection to MySQL is opened. You can use this to set
     MySQL options for your connection, such as disabling autocommit.

   * `Character Set' is a pop-up list from which you can select the
     default character set to be used with this connection. The
     Character Set option was added in 3.5.17.

The `Advanced' tab enables you to configure Connector/ODBC connection
parameters. Refer to *Note
connector-odbc-configuration-connection-parameters::, for information
about the meaning of these options.

Connector/ODBC Connection Advanced Dialog


File: manual.info,  Node: connector-odbc-configuration-dsn-windows-3-51-command-line,  Next: connector-odbc-configuration-dsn-windows-5-1,  Prev: connector-odbc-configuration-dsn-windows-3-51,  Up: connector-odbc-configuration-dsn-windows

20.1.4.5 Configuring a Connector/ODBC 3.51 DSN on Windows, using the command-line
.................................................................................

Use `myodbc3i.exe' when configuring Connector/ODBC 3.51 from the
command-line.

Execute `myodbc3i.exe' without arguments to view a list of available
options.


File: manual.info,  Node: connector-odbc-configuration-dsn-windows-5-1,  Next: connector-odbc-configuration-dsn-windows-5-1-command-line,  Prev: connector-odbc-configuration-dsn-windows-3-51-command-line,  Up: connector-odbc-configuration-dsn-windows

20.1.4.6 Configuring a Connector/ODBC 5.1 DSN on Windows
........................................................

The DSN configuration when using Connector/ODBC 5.1.1 and later has a
slightly different layout. Also, due to the native Unicode support
within Connector/ODBC 5.1, you no longer need to specify the initial
character set to be used with your connection.

To add or configure a Connector/ODBC 5.1 DSN on Windows, use either the
command-line, or the `ODBC Data Source Administrator' GUI.

  1. Open the `ODBC Data Source Administrator'.

  2. To create a System DSN (which will be available to all users) ,
     select the `System DSN' tab.  To create a User DSN, which will be
     unique only to the current user, click the `Add...' button.

  3. You will need to select the ODBC driver for this DSN.

     `MySQL ODBC Driver Selection' Dialog

     Select `MySQL ODBC 5.1 Driver', then click `Finish'.

  4. You now need to configure the specific fields for the DSN you are
     creating through the `Connection Parameters' dialog.

     `Add Data Source Name' Dialog for Connector/ODBC 5.1

     In the `Data Source Name' box, enter the name of the data source
     to access. It can be any valid name that you choose.

  5. In the `Description' box, enter some text to help identify the
     connection.

  6. In the `Server' field, enter the name of the MySQL server host to
     access. By default, it is `localhost'.

  7. In the `User' field, enter the user name to use for this
     connection.

  8. In the `Password' field, enter the corresponding password for this
     connection.

  9. The `Database' pop-up should automatically populate with the list
     of databases that the user has permissions to access.

 10. To communicate over a different TCP/IP port than the default
     (3306), change the value of the `Port'.

 11. Click `OK' to save the DSN.

You can verify the connection using the parameters you have entered by
clicking the `Test' button. If the connection could be made
successfully, you will be notified with a `Success; connection was
made!' dialog.

You can configure a number of options for a specific DSN by using the
`Details' button.

Connector/ODBC Connect Options Dialog

The `Details' button opens a tabbed display which enables you to set
additional options:

   * `Flags 1', `Flags 2', and `Flags 3' enable you to select the
     additional flags for the DSN connection. For more information on
     these flags, see *Note
     connector-odbc-configuration-connection-parameters::.

   * `Debug' enables you to enable ODBC debugging to record the queries
     you execute through the DSN to the `myodbc.sql' file. For more
     information, see *Note connector-odbc-configuration-trace::.

   * `SSL Settings' configures the additional options required for
     using the Secure Sockets Layer (SSL) when communicating with MySQL
     server. Note that you must have enabled SSL and configured the
     MySQL server with suitable certificates to communicate over SSL.

     Connector/ODBC 5.1 SSL Configuration

The `Advanced' tab enables you to configure Connector/ODBC connection
parameters. Refer to *Note
connector-odbc-configuration-connection-parameters::, for information
about the meaning of these options.


File: manual.info,  Node: connector-odbc-configuration-dsn-windows-5-1-command-line,  Next: connector-odbc-configuration-dsn-windows-problems,  Prev: connector-odbc-configuration-dsn-windows-5-1,  Up: connector-odbc-configuration-dsn-windows

20.1.4.7 Configuring a Connector/ODBC 5.1 DSN on Windows, using the command-line
................................................................................

Use `myodbc-installer.exe' when configuring Connector/ODBC 5.1 or later
from the command-line.

Execute `myodbc-installer.exe' without arguments to view a list of
available options.


File: manual.info,  Node: connector-odbc-configuration-dsn-windows-problems,  Prev: connector-odbc-configuration-dsn-windows-5-1-command-line,  Up: connector-odbc-configuration-dsn-windows

20.1.4.8 Errors and Debugging
.............................

This section answers Connector/ODBC connection-related questions.

   * *While configuring a Connector/ODBC DSN, a `Could Not Load
     Translator or Setup Library' error occurs*

     For more information, refer to MS KnowledgeBase Article(Q260558)
     (http://support.microsoft.com/default.aspx?scid=kb;EN-US;q260558).
     Also, make sure you have the latest valid `ctl3d32.dll' in your
     system directory.

   * On Windows, the default `myodbc3.dll' is compiled for optimal
     performance. To debug Connector/ODBC 3.51 (for example, to enable
     tracing), instead use `myodbc3d.dll'. To install this file, copy
     `myodbc3d.dll' over the installed `myodbc3.dll' file. Make sure to
     revert back to the release version of the driver DLL once you are
     done with the debugging, because the debug version may cause
     performance issues. Note that the `myodbc3d.dll' isn't included in
     Connector/ODBC 3.51.07 through 3.51.11. If you are using one of
     these versions, copy that DLL from a previous version (for
     example, 3.51.06).


File: manual.info,  Node: connector-odbc-configuration-dsn-macosx,  Next: connector-odbc-configuration-dsn-unix,  Prev: connector-odbc-configuration-dsn-windows,  Up: connector-odbc-configuration

20.1.4.9 Configuring a Connector/ODBC DSN on Mac OS X
.....................................................

To configure a DSN on Mac OS X, you can either use the command-line
utility (`myodbc3i' with connector/OCBC 3.51, or `myodbc-installer' with
connector/ODBC 5.1), edit the `odbc.ini' file within the `Library/ODBC'
directory of the user, or use the ODBC Administrator GUI. If you have
Mac OS X 10.2 or earlier, refer to *Note
connector-odbc-configuration-dsn-unix::. Select whether to create a
User DSN or a System DSN. When adding a System DSN, you might need to
authenticate with the system.  Click the padlock and enter a user and
password with administrator privileges.

For correct operation of ODBC Administrator, ensure that the
`/Library/ODBC/odbc.ini' file used to set up ODBC connectivity and DSNs
are writable by the `admin' group. If this file is not writable by this
group, then the ODBC Administrator may fail, or may appear to work but
not generate the correct entry.

*Warning*:

There are known issues with the OS X ODBC Administrator and
Connector/ODBC that may prevent you from creating a DSN using this
method. In this case you should use the command-line or edit the
`odbc.ini' file directly. Note that existing DSNs or those that you
create using the `myodbc3i' or `myodbc-installer' tool can still be
checked and edited using ODBC Administrator.

To create a DSN using the `myodbc3i' utility, you need only specify the
DSN type and the DSN connection string. For example:

     shell> myodbc3i -a -s -t"DSN=mydb;DRIVER=MySQL ODBC 3.51 Driver;SERVER=mysql;USER=username;PASSWORD=pass"

To use ODBC Administrator:

  1. Open the ODBC Administrator from the `Utilities' folder in the
     `Applications' folder.

     `ODBC Administrator Main Panel' Dialog

  2. On the User DSN or System DSN panel, click `Add.'

  3. Select the Connector/ODBC driver and click `OK'.

  4. You will be presented with the `Data Source Name' dialog. Enter
     The `Data Source Name' and an optional `Description' for the DSN.

     `ODBC Administrator Add DSN' Dialog

  5. Click `Add' to add a new keyword/value pair to the panel. You
     should configure at least four pairs to specify the `server',
     `username', `password' and `database' connection parameters. See
     *Note connector-odbc-configuration-connection-parameters::.

  6. Click `OK' to add the DSN to the list of configured data source
     names.

A completed DSN configuration may look like this:

`ODBC Administrator Sample DSN' Dialog

You can configure other ODBC options in your DSN by adding further
keyword/value pairs and setting the corresponding values. See *Note
connector-odbc-configuration-connection-parameters::.


File: manual.info,  Node: connector-odbc-configuration-dsn-unix,  Next: connector-odbc-configuration-connection-without-dsn,  Prev: connector-odbc-configuration-dsn-macosx,  Up: connector-odbc-configuration

20.1.4.10 Configuring a Connector/ODBC DSN on Unix
..................................................

On `Unix', you configure DSN entries directly in the `odbc.ini' file.
Here is a typical `odbc.ini' file that configures `myodbc3' as the DSN
name for Connector/ODBC 3.51:

     ;
     ;  odbc.ini configuration for Connector/ODBC and Connector/ODBC 3.51 drivers
     ;

     [ODBC Data Sources]
     myodbc3     = MyODBC 3.51 Driver DSN

     [myodbc3]
     Driver       = /usr/local/lib/libmyodbc3.so
     Description  = Connector/ODBC 3.51 Driver DSN
     SERVER       = localhost
     PORT         =
     USER         = root
     Password     =
     Database     = test
     OPTION       = 3
     SOCKET       =

     [Default]
     Driver       = /usr/local/lib/libmyodbc3.so
     Description  = Connector/ODBC 3.51 Driver DSN
     SERVER       = localhost
     PORT         =
     USER         = root
     Password     =
     Database     = test
     OPTION       = 3
     SOCKET       =

Refer to the *Note connector-odbc-configuration-connection-parameters::,
for the list of connection parameters that can be supplied.

*Note*:

If you are using `unixODBC', you can use the following tools to set up
the DSN:

   * ODBCConfig GUI tool(HOWTO: ODBCConfig
     (http://www.unixodbc.org/config.html))

   * odbcinst

In some cases when using `unixODBC', you might get this error:

     Data source name not found and no default driver specified

If this happens, make sure the `ODBCINI' and `ODBCSYSINI' environment
variables are pointing to the right `odbc.ini' file. For example, if
your `odbc.ini' file is located in `/usr/local/etc', set the environment
variables like this:

     export ODBCINI=/usr/local/etc/odbc.ini
     export ODBCSYSINI=/usr/local/etc


File: manual.info,  Node: connector-odbc-configuration-connection-without-dsn,  Next: connector-odbc-configuration-connection-pooling,  Prev: connector-odbc-configuration-dsn-unix,  Up: connector-odbc-configuration

20.1.4.11 Connecting Without a Predefined DSN
.............................................

You can connect to the MySQL server using SQLDriverConnect, by
specifying the `DRIVER' name field. Here are the connection strings for
Connector/ODBC using DSN-Less connections:

*For Connector/ODBC 3.51:*

     ConnectionString = "DRIVER={MySQL ODBC 3.51 Driver};\
                        SERVER=localhost;\
                        DATABASE=test;\
                        USER=venu;\
                        PASSWORD=venu;\
                        OPTION=3;"

If your programming language converts backslash followed by whitespace
to a space, it is preferable to specify the connection string as a
single long string, or to use a concatenation of multiple strings that
does not add spaces in between. For example:

     ConnectionString = "DRIVER={MySQL ODBC 3.51 Driver};"
                        "SERVER=localhost;"
                        "DATABASE=test;"
                        "USER=venu;"
                        "PASSWORD=venu;"
                        "OPTION=3;"

Note

Note that on Mac OS X you may need to specify the full path to the
Connector/ODBC driver library.

Refer to the *Note connector-odbc-configuration-connection-parameters::,
for the list of connection parameters that can be supplied.


File: manual.info,  Node: connector-odbc-configuration-connection-pooling,  Next: connector-odbc-configuration-trace,  Prev: connector-odbc-configuration-connection-without-dsn,  Up: connector-odbc-configuration

20.1.4.12 ODBC Connection Pooling
.................................

Connection pooling enables the ODBC driver to re-use existing
connections to a given database from a pool of connections, instead of
opening a new connection each time the database is accessed. By
enabling connection pooling you can improve the overall performance of
your application by lowering the time taken to open a connection to a
database in the connection pool.

For more information about connection pooling:
`http://support.microsoft.com/default.aspx?scid=kb;EN-US;q169470'.


File: manual.info,  Node: connector-odbc-configuration-trace,  Prev: connector-odbc-configuration-connection-pooling,  Up: connector-odbc-configuration

20.1.4.13 Getting an ODBC Trace File
....................................

* Menu:

* connector-odbc-configuration-trace-windows::  Enabling ODBC Tracing on Windows
* connector-odbc-configuration-trace-macosx::  Enabling ODBC Tracing on Mac OS X
* connector-odbc-configuration-trace-unix::  Enabling ODBC Tracing on Unix
* connector-odbc-configuration-trace-log::  Enabling a Connector/ODBC Log

If you encounter difficulties or problems with Connector/ODBC, you
should start by making a log file from the `ODBC Manager' and
Connector/ODBC. This is called _tracing_, and is enabled through the
ODBC Manager. The procedure for this differs for Windows, Mac OS X and
Unix.


File: manual.info,  Node: connector-odbc-configuration-trace-windows,  Next: connector-odbc-configuration-trace-macosx,  Prev: connector-odbc-configuration-trace,  Up: connector-odbc-configuration-trace

20.1.4.14 Enabling ODBC Tracing on Windows
..........................................

To enable the trace option on Windows:

  1. The `Tracing' tab of the ODBC Data Source Administrator dialog box
     enables you to configure the way ODBC function calls are traced.

     ODBC Data Source Administrator Tracing Dialog

  2. When you activate tracing from the `Tracing' tab, the `Driver
     Manager' logs all ODBC function calls for all subsequently run
     applications.

  3. ODBC function calls from applications running before tracing is
     activated are not logged. ODBC function calls are recorded in a
     log file you specify.

  4. Tracing ceases only after you click `Stop Tracing Now'. Remember
     that while tracing is on, the log file continues to increase in
     size and that tracing affects the performance of all your ODBC
     applications.


File: manual.info,  Node: connector-odbc-configuration-trace-macosx,  Next: connector-odbc-configuration-trace-unix,  Prev: connector-odbc-configuration-trace-windows,  Up: connector-odbc-configuration-trace

20.1.4.15 Enabling ODBC Tracing on Mac OS X
...........................................

To enable the trace option on Mac OS X 10.3 or later you should use the
`Tracing' tab within ODBC Administrator .

  1. Open the ODBC Administrator.

  2. Select the `Tracing' tab.

     ODBC Administrator Tracing Dialog

  3. Select the `Enable Tracing' check box.

  4. Enter the location to save the Tracing log. To append information
     to an existing log file, click the `Choose...' button.


File: manual.info,  Node: connector-odbc-configuration-trace-unix,  Next: connector-odbc-configuration-trace-log,  Prev: connector-odbc-configuration-trace-macosx,  Up: connector-odbc-configuration-trace

20.1.4.16 Enabling ODBC Tracing on Unix
.......................................

To enable the trace option on Mac OS X 10.2 (or earlier) or Unix you
must add the `trace' option to the ODBC configuration:

  1. On Unix, you need to explicitly set the `Trace' option in the
     `ODBC.INI' file.

     Set the tracing `ON' or `OFF' by using `TraceFile' and `Trace'
     parameters in `odbc.ini' as shown below:

          TraceFile  = /tmp/odbc.trace
          Trace      = 1

     `TraceFile' specifies the name and full path of the trace file and
     `Trace' is set to `ON' or `OFF'. You can also use `1' or `YES' for
     `ON' and `0' or `NO' for `OFF'. If you are using `ODBCConfig' from
     `unixODBC', then follow the instructions for tracing `unixODBC'
     calls at HOWTO-ODBCConfig (http://www.unixodbc.org/config.html).


File: manual.info,  Node: connector-odbc-configuration-trace-log,  Prev: connector-odbc-configuration-trace-unix,  Up: connector-odbc-configuration-trace

20.1.4.17 Enabling a Connector/ODBC Log
.......................................

To generate a Connector/ODBC log, do the following:

  1. Within Windows, enable the `Trace Connector/ODBC' option flag in
     the Connector/ODBC connect/configure screen. The log is written to
     file `C:\myodbc.log'. If the trace option is not remembered when
     you are going back to the above screen, it means that you are not
     using the `myodbcd.dll' driver, see *Note
     connector-odbc-configuration-dsn-windows-problems::.

     On Mac OS X, Unix, or if you are using DSN-Less connection, then
     you need to supply `OPTION=4' in the connection string or set the
     corresponding keyword/value pair in the DSN.

  2. Start your application and try to get it to fail. Then check the
     Connector/ODBC trace file to find out what could be wrong.

If you need help determining what is wrong, see *Note
connector-odbc-support-community::.


File: manual.info,  Node: connector-odbc-examples,  Next: connector-odbc-reference,  Prev: connector-odbc-configuration,  Up: connector-odbc

20.1.5 Connector/ODBC Examples
------------------------------

* Menu:

* connector-odbc-examples-overview::  Basic Connector/ODBC Application Steps
* connector-odbc-examples-walkthrough::  Step-by-step Guide to Connecting to a MySQL Database through Connector/ODBC
* connector-odbc-examples-tools::  Connector/ODBC and Third-Party ODBC Tools
* connector-odbc-examples-tools-with-access::  Using Connector/ODBC with Microsoft Access
* connector-odbc-examples-tools-with-wordexcel::  Using Connector/ODBC with Microsoft Word or Excel
* connector-odbc-examples-tools-with-crystalreports::  Using Connector/ODBC with Crystal Reports
* connector-odbc-examples-programming::  Connector/ODBC Programming

Once you have configured a DSN to provide access to a database, how you
access and use that connection is dependent on the application or
programming language. As ODBC is a standardized interface, any
application or language that supports ODBC can use the DSN and connect
to the configured database.


File: manual.info,  Node: connector-odbc-examples-overview,  Next: connector-odbc-examples-walkthrough,  Prev: connector-odbc-examples,  Up: connector-odbc-examples

20.1.5.1 Basic Connector/ODBC Application Steps
...............................................

Interacting with a MySQL server from an applications using the
Connector/ODBC typically involves the following operations:

   * Configure the Connector/ODBC DSN

   * Connect to MySQL server

   * Initialization operations

   * Execute SQL statements

   * Retrieve results

   * Perform Transactions

   * Disconnect from the server

Most applications use some variation of these steps. The basic
application steps are shown in the following diagram:

Connector/ODBC Programming Flowchart


File: manual.info,  Node: connector-odbc-examples-walkthrough,  Next: connector-odbc-examples-tools,  Prev: connector-odbc-examples-overview,  Up: connector-odbc-examples

20.1.5.2 Step-by-step Guide to Connecting to a MySQL Database through Connector/ODBC
....................................................................................

A typical situation where you would install Connector/ODBC is to access
a database on a Linux or Unix host from a Windows machine.

As an example of the process required to set up access between two
machines, the steps below take you through the basic steps.  These
instructions assume that you connect to system ALPHA from system BETA
with a user name and password of `myuser' and `mypassword'.

On system ALPHA (the MySQL server) follow these steps:

  1. Start the MySQL server.

  2. Use *Note `GRANT': grant. to set up an account with a user name of
     `myuser' that can connect from system BETA using a password of
     `myuser' to the database `test':

          GRANT ALL ON test.* to 'myuser'@'BETA' IDENTIFIED BY 'mypassword';

     For more information about MySQL privileges, refer to *Note
     user-account-management::.

On system BETA (the Connector/ODBC client), follow these steps:

  1. Configure a Connector/ODBC DSN using parameters that match the
     server, database and authentication information that you have just
     configured on system ALPHA.

     Parameter  Value         Comment
     DSN        remote_test   A name to identify the connection.
     SERVER     ALPHA         The address of the remote server.
     DATABASE   test          The name of the default database.
     USER       myuser        The user name configured for access to this
                              database.
     PASSWORD   mypassword    The password for `myuser'.

  2. Using an ODBC-capable application, such as Microsoft Office,
     connect to the MySQL server using the DSN you have just created.
     If the connection fails, use tracing to examine the connection
     process. See *Note connector-odbc-configuration-trace::, for more
     information.


File: manual.info,  Node: connector-odbc-examples-tools,  Next: connector-odbc-examples-tools-with-access,  Prev: connector-odbc-examples-walkthrough,  Up: connector-odbc-examples

20.1.5.3 Connector/ODBC and Third-Party ODBC Tools
..................................................

Once you have configured your Connector/ODBC DSN, you can access your
MySQL database through any application that supports the ODBC
interface, including programming languages and third-party
applications. This section contains guides and help on using
Connector/ODBC with various ODBC-compatible tools and applications,
including Microsoft Word, Microsoft Excel and Adobe/Macromedia
ColdFusion.

Connector/ODBC has been tested with the following applications.

Publisher          Application        Notes
Adobe              ColdFusion         Formerly Macromedia ColdFusion
Borland            C++ Builder        
                   Builder 4          
                   Delphi             
Business Objects   Crystal Reports    
Claris             Filemaker Pro      
Corel              Paradox            
Computer           Visual Objects     Also known as CAVO
Associates                            
                   AllFusion ERwin    
                   Data Modeler       
Gupta              Team Developer     Previously known as Centura Team
                                      Developer; Gupta SQL/Windows
Gensym             G2-ODBC Bridge     
Inline             iHTML              
Lotus              Notes              Versions 4.5 and 4.6
Microsoft          Access             
                   Excel              
                   Visio Enterprise   
                   Visual C++         
                   Visual Basic       
                   ODBC.NET           Using C#, Visual Basic, C++
                   FoxPro             
                   Visual Interdev    
OpenOffice.org     OpenOffice.org     
Perl               DBD::ODBC          
Pervasive Software DataJunction       
Sambar             Sambar Server      
Technologies                          
SPSS               SPSS               
SoftVelocity       Clarion            
SQLExpress         SQLExpress for     
                   Xbase++            
Sun                StarOffice         
SunSystems         Vision             
Sybase             PowerBuilder       
                   PowerDesigner      
theKompany.com     Data Architect     

If you know of any other applications that work with Connector/ODBC,
please send mail to <myodbc@lists.mysql.com> about them.


File: manual.info,  Node: connector-odbc-examples-tools-with-access,  Next: connector-odbc-examples-tools-with-wordexcel,  Prev: connector-odbc-examples-tools,  Up: connector-odbc-examples

20.1.5.4 Using Connector/ODBC with Microsoft Access
...................................................

* Menu:

* connector-odbc-examples-tools-with-access-export::  Exporting Access Data to MySQL
* connector-odbc-examples-tools-with-access-import::  Importing MySQL Data to Access
* connector-odbc-examples-tools-with-access-linked-tables::  Using Microsoft Access as a Front-end to MySQL

You can use MySQL database with Microsoft Access using Connector/ODBC.
The MySQL database can be used as an import source, an export source,
or as a linked table for direct use within an Access application, so
you can use Access as the front-end interface to a MySQL database.


File: manual.info,  Node: connector-odbc-examples-tools-with-access-export,  Next: connector-odbc-examples-tools-with-access-import,  Prev: connector-odbc-examples-tools-with-access,  Up: connector-odbc-examples-tools-with-access

20.1.5.5 Exporting Access Data to MySQL
.......................................

To export a table of data from an Access database to MySQL, follow
these instructions:

  1. When you open an Access database or an Access project, a Database
     window appears. It displays shortcuts for creating new database
     objects and opening existing objects.

     Access Database

  2. Click the name of the `table' or `query' to export, and then in the
     `File' menu, select `Export'.

  3. In the `Export Object Type OBJECT NAME To' dialog box, in the
     `Save As Type' box, select `ODBC Databases ()' as shown here:

     Selecting an ODBC Database

  4. In the `Export' dialog box, enter a name for the file (or use the
     suggested name), and then select `OK'.

  5. The Select Data Source dialog box is displayed; it lists the
     defined data sources for any ODBC drivers installed on your
     computer. Click either the File Data Source or Machine Data Source
     tab, and then double-click the Connector/ODBC or Connector/ODBC
     3.51 data source to export to. To define a new data source for
     Connector/ODBC, please *Note
     connector-odbc-configuration-dsn-windows::.

*Note*:

Ensure that the information that you are exporting to the MySQL table
is valid for the corresponding MySQL data types.  Values that are
outside of the supported range of the MySQL data type but valid within
Access may trigger an `overflow' error during the export.

Microsoft Access connects to the MySQL Server through this data source
and exports new tables and or data.


File: manual.info,  Node: connector-odbc-examples-tools-with-access-import,  Next: connector-odbc-examples-tools-with-access-linked-tables,  Prev: connector-odbc-examples-tools-with-access-export,  Up: connector-odbc-examples-tools-with-access

20.1.5.6 Importing MySQL Data to Access
.......................................

To import a table or tables from MySQL to Access, follow these
instructions:

  1. Open a database, or switch to the Database window for the open
     database.

  2. To import tables, on the `File' menu, point to `Get External
     Data', and then click `Import'.

  3. In the `Import' dialog box, in the Files Of Type box, select `ODBC
     Databases ()'. The Select Data Source dialog box lists the defined
     data sources `The Select Data Source' dialog box is displayed; it
     lists the defined data source names.

  4. If the ODBC data source that you selected requires you to log on,
     enter your login ID and password (additional information might
     also be required), and then click `OK'.

  5. Microsoft Access connects to the MySQL server through `ODBC data
     source ' and displays the list of tables that you can `import'.

  6. Click each table to `import', and then click `OK'.


File: manual.info,  Node: connector-odbc-examples-tools-with-access-linked-tables,  Prev: connector-odbc-examples-tools-with-access-import,  Up: connector-odbc-examples-tools-with-access

20.1.5.7 Using Microsoft Access as a Front-end to MySQL
.......................................................

You can use Microsoft Access as a front end to a MySQL database by
linking tables within your Microsoft Access database to tables that
exist within your MySQL database. When a query is requested on a table
within Access, ODBC is used to execute the queries on the MySQL
database instead.

*To create a linked table*:

  1. Open the Access database that you want to link to MySQL.

  2. From the `File', choose `Get External Data->Link Tables'.

     Linking Microsoft Access tables to MySQL tables

  3. From the browser, choose `ODBC Databases ()' from the `Files of
     type' pop-up.

  4. In the `Select Data Source' window, choose an existing DSN, either
     from a `File Data Source' or `Machine Data Source'.You can also
     create a new DSN using the `New...' button. For more information
     on creating a DSN see *Note
     connector-odbc-configuration-dsn-windows::.

     Linking Microsoft Access tables to MySQL tables, choosing a DSN

  5. In the `Link Tables' dialog, select one or more tables from the
     MySQL database. A link will be created to each table that you
     select from this list.

     Linking Microsoft Access tables to MySQL tables, table selection

  6. If Microsoft Access is unable to determine the unique record
     identifier for a table automatically then it may ask you to
     confirm the column, or combination of columns, to be used to
     uniquely identify each row from the source table. Select the
     columns to use and click `OK'.

     Linking Microsoft Access tables to MySQL tables, choosing unique
     record identifier

Once the process has been completed, you can now build interfaces and
queries to the linked tables just as you would for any Access database.

Use the following procedure to view or to refresh links when the
structure or location of a linked table has changed. The Linked Table
Manager lists the paths to all currently linked tables.

*To view or refresh links*:

  1. Open the database that contains links to MySQL tables.

  2. On the `Tools' menu, point to `Add-ins' (`Database Utilities' in
     Access 2000 or newer), and then click `Linked Table Manager'.

  3. Select the check box for the tables whose links you want to
     refresh.

  4. Click OK to refresh the links.

Microsoft Access confirms a successful refresh or, if the table wasn't
found, displays the `Select New Location of' <table name> dialog box in
which you can specify its the table's new location. If several selected
tables have moved to the new location that you specify, the Linked
Table Manager searches that location for all selected tables, and
updates all links in one step.

*To change the path for a set of linked tables*:

  1. Open the database that contains links to tables.

  2. On the `Tools' menu, point to `Add-ins' (`Database Utilities' in
     Access 2000 or newer), and then click `Linked Table Manager'.

  3. Select the `Always Prompt For A New Location' check box.

  4. Select the check box for the tables whose links you want to
     change, and then click `OK'.

  5. In the `Select New Location of' <table name> dialog box, specify
     the new location, click `Open', and then click `OK'.


File: manual.info,  Node: connector-odbc-examples-tools-with-wordexcel,  Next: connector-odbc-examples-tools-with-crystalreports,  Prev: connector-odbc-examples-tools-with-access,  Up: connector-odbc-examples

20.1.5.8 Using Connector/ODBC with Microsoft Word or Excel
..........................................................

You can use Microsoft Word and Microsoft Excel to access information
from a MySQL database using Connector/ODBC. Within Microsoft Word, this
facility is most useful when importing data for mailmerge, or for
tables and data to be included in reports.  Within Microsoft Excel, you
can execute queries on your MySQL server and import the data directly
into an Excel Worksheet, presenting the data as a series of rows and
columns.

With both applications, data is accessed and imported into the
application using Microsoft Query , which enables you to execute a
query though an ODBC source. You use Microsoft Query to build the SQL
statement to be executed, selecting the tables, fields, selection
criteria and sort order.  For example, to insert information from a
table in the World test database into an Excel spreadsheet, using the
DSN samples shown in *Note connector-odbc-configuration:::

  1. Create a new Worksheet.

  2. From the `Data' menu, choose `Import External Data', and then
     select `New Database Query'.

  3. Microsoft Query will start.  First, you need to choose the data
     source, by selecting an existing Data Source Name.

     Microsoft Query, Choose Data Source

  4. Within the `Query Wizard', you must choose the columns to import.
     The list of tables available to the user configured through the
     DSN is shown on the left, the columns that will be added to your
     query are shown on the right. The columns you choose are
     equivalent to those in the first section of a *Note `SELECT':
     select.  query. Click `Next' to continue.

     Microsoft Query, Choose Columns

  5. You can filter rows from the query (the equivalent of a `WHERE'
     clause) using the `Filter Data' dialog. Click `Next' to continue.

     Microsoft Query, Filter Data

  6. Select an (optional) sort order for the data. This is equivalent
     to using a `ORDER BY' clause in your SQL query. You can select up
     to three fields for sorting the information returned by the query.
     Click `Next' to continue.

     Microsoft Query, Sort Order

  7. Select the destination for your query. You can select to return
     the data Microsoft Excel, where you can choose a worksheet and
     cell where the data will be inserted; you can continue to view the
     query and results within Microsoft Query, where you can edit the
     SQL query and further filter and sort the information returned; or
     you can create an OLAP Cube from the query, which can then be used
     directly within Microsoft Excel. Click `Finish'.

     Microsoft Query, Selecting a destination

The same process can be used to import data into a Word document, where
the data will be inserted as a table. This can be used for mail merge
purposes (where the field data is read from a Word table), or where you
want to include data and reports within a report or other document.


File: manual.info,  Node: connector-odbc-examples-tools-with-crystalreports,  Next: connector-odbc-examples-programming,  Prev: connector-odbc-examples-tools-with-wordexcel,  Up: connector-odbc-examples

20.1.5.9 Using Connector/ODBC with Crystal Reports
..................................................

Crystal Reports can use an ODBC DSN to connect to a database from which
you to extract data and information for reporting purposes.

*Note*:

There is a known issue with certain versions of Crystal Reports where
the application is unable to open and browse tables and fields through
an ODBC connection. Before using Crystal Reports with MySQL, please
ensure that you have update to the latest version, including any
outstanding service packs and hotfixes. For more information on this
issue, see the Business) Objects Knowledgebase
(http://support.crystaldecisions.com/library/kbase/new_articles/c2013269.asp)
for more information.

For example, to create a simple crosstab report within Crystal Reports
XI, you should follow these steps:

  1. Create a DSN using the `Data Sources (ODBC)' tool. You can either
     specify a complete database, including user name and password, or
     you can build a basic DSN and use Crystal Reports to set the user
     name and password.

     For the purposes of this example, a DSN that provides a connection
     to an instance of the MySQL Sakila sample database has been
     created.

  2. Open Crystal Reports and create a new project, or an open an
     existing reporting project into which you want to insert data from
     your MySQL data source.

  3. Start the Cross-Tab Report Wizard, either by clicking the option
     on the Start Page. Expand the `Create New Connection' folder, then
     expand the `ODBC (RDO)' folder to obtain a list of ODBC data
     sources.

     You will be asked to select a data source.

     Selecting an Data Source in Crystal Reports

  4. When you first expand the `ODBC (RDO)' folder you will be
     presented the Data Source Selection screen. From here you can
     select either a pre-configured DSN, open a file-based DSN or enter
     and manual connection string. For this example, the `Sakila' DSN
     will be used.

     If the DSN contains a user name/password combination, or you want
     to use different authentication credentials, click `Next' to enter
     the user name and password that you want to use. Otherwise, click
     `Finish' to continue the data source selection wizard.

     Selecting an ODBC Data Source in Crystal Reports

  5. You will be returned the Cross-Tab Report Creation Wizard.  You
     now need to select the database and tables that you want to
     include in your report. For our example, we will expand the
     selected Sakila database. Click the `city' table and use the `>'
     button to add the table to the report. Then repeat the action with
     the `country' table. Alternatively you can select multiple tables
     and add them to the report.

     Finally, you can select the parent `Sakila' resource and add of
     the tables to the report.

     Once you have selected the tables you want to include, click
     `Next' to continue.

     Selecting an tables in Crystal Reports

  6. Crystal Reports will now read the table definitions and
     automatically identify the links between the tables. The
     identification of links between tables enables Crystal Reports to
     automatically lookup and summarize information based on all the
     tables in the database according to your query. If Crystal Reports
     is unable to perform the linking itself, you can manually create
     the links between fields in the tables you have selected.

     Click `Next' to continue the process.

     Table links/structure in Crystal Reports

  7. You can now select the columns and rows that to include within the
     Cross-Tab report. Drag and drop or use the `>' buttons to add
     fields to each area of the report. In the example shown, we will
     report on cities, organized by country, incorporating a count of
     the number of cities within each country. If you want to browse
     the data, select a field and click the `Browse Data...' button.

     Click `Next' to create a graph of the results. Since we are not
     creating a graph from this data, click `Finish' to generate the
     report.

     Cross-tab definition in Crystal Reports

  8. The finished report will be shown, a sample of the output from the
     Sakila sample database is shown below.

     Cross-tab final report in Crystal Reports

Once the ODBC connection has been opened within Crystal Reports, you
can browse and add any fields within the available tables into your
reports.


File: manual.info,  Node: connector-odbc-examples-programming,  Prev: connector-odbc-examples-tools-with-crystalreports,  Up: connector-odbc-examples

20.1.5.10 Connector/ODBC Programming
....................................

* Menu:

* connector-odbc-examples-programming-vb::  Using Connector/ODBC with Visual Basic Using ADO, DAO and RDO
* connector-odbc-examples-programming-net::  Using Connector/ODBC with .NET

With a suitable ODBC Manager and the Connector/ODBC driver installed,
any programming language or environment that can support ODBC should be
able to connect to a MySQL database through Connector/ODBC.

This includes, but is certainly not limited to, Microsoft support
languages (including Visual Basic, C# and interfaces such as ODBC.NET),
Perl (through the DBI module, and the DBD::ODBC driver).


File: manual.info,  Node: connector-odbc-examples-programming-vb,  Next: connector-odbc-examples-programming-net,  Prev: connector-odbc-examples-programming,  Up: connector-odbc-examples-programming

20.1.5.11 Using Connector/ODBC with Visual Basic Using ADO, DAO and RDO
.......................................................................

* Menu:

* connector-odbc-examples-programming-vb-ado::  ADO: `rs.addNew', `rs.delete', and `rs.update'
* connector-odbc-examples-programming-vb-dao::  DAO: `rs.addNew', `rs.update', and Scrolling
* connector-odbc-examples-programming-vb-rdo::  RDO: `rs.addNew' and `rs.update'

This section contains simple examples of the use of MySQL ODBC 3.51
Driver with ADO, DAO and RDO.


File: manual.info,  Node: connector-odbc-examples-programming-vb-ado,  Next: connector-odbc-examples-programming-vb-dao,  Prev: connector-odbc-examples-programming-vb,  Up: connector-odbc-examples-programming-vb

20.1.5.12 ADO: `rs.addNew', `rs.delete', and `rs.update'
........................................................

The following ADO (ActiveX Data Objects) example creates a table
`my_ado' and demonstrates the use of `rs.addNew', `rs.delete', and
`rs.update'.

     Private Sub myodbc_ado_Click()

     Dim conn As ADODB.Connection
     Dim rs As ADODB.Recordset
     Dim fld As ADODB.Field
     Dim sql As String

     'connect to MySQL server using MySQL ODBC 3.51 Driver
     Set conn = New ADODB.Connection
     conn.ConnectionString = "DRIVER={MySQL ODBC 3.51 Driver};"_
     & "SERVER=localhost;"_
     & " DATABASE=test;"_
     & "UID=venu;PWD=venu; OPTION=3"

     conn.Open

     'create table
     conn.Execute "DROP TABLE IF EXISTS my_ado"
     conn.Execute "CREATE TABLE my_ado(id int not null primary key, name varchar(20)," _
     & "txt text, dt date, tm time, ts timestamp)"

     'direct insert
     conn.Execute "INSERT INTO my_ado(id,name,txt) values(1,100,'venu')"
     conn.Execute "INSERT INTO my_ado(id,name,txt) values(2,200,'MySQL')"
     conn.Execute "INSERT INTO my_ado(id,name,txt) values(3,300,'Delete')"

     Set rs = New ADODB.Recordset
     rs.CursorLocation = adUseServer

     'fetch the initial table ..
     rs.Open "SELECT * FROM my_ado", conn
     Debug.Print rs.RecordCount
     rs.MoveFirst
     Debug.Print String(50, "-") & "Initial my_ado Result Set " & String(50, "-")
     For Each fld In rs.Fields
     Debug.Print fld.Name,
     Next
     Debug.Print

     Do Until rs.EOF
     For Each fld In rs.Fields
     Debug.Print fld.Value,
     Next
     rs.MoveNext
     Debug.Print
     Loop
     rs.Close

     'rs insert
     rs.Open "select * from my_ado", conn, adOpenDynamic, adLockOptimistic
     rs.AddNew
     rs!Name = "Monty"
     rs!txt = "Insert row"
     rs.Update
     rs.Close

     'rs update
     rs.Open "SELECT * FROM my_ado"
     rs!Name = "update"
     rs!txt = "updated-row"
     rs.Update
     rs.Close

     'rs update second time..
     rs.Open "SELECT * FROM my_ado"
     rs!Name = "update"
     rs!txt = "updated-second-time"
     rs.Update
     rs.Close

     'rs delete
     rs.Open "SELECT * FROM my_ado"
     rs.MoveNext
     rs.MoveNext
     rs.Delete
     rs.Close

     'fetch the updated table ..
     rs.Open "SELECT * FROM my_ado", conn
     Debug.Print rs.RecordCount
     rs.MoveFirst
     Debug.Print String(50, "-") & "Updated my_ado Result Set " & String(50, "-")
     For Each fld In rs.Fields
     Debug.Print fld.Name,
     Next
     Debug.Print

     Do Until rs.EOF
     For Each fld In rs.Fields
     Debug.Print fld.Value,
     Next
     rs.MoveNext
     Debug.Print
     Loop
     rs.Close
     conn.Close
     End Sub


File: manual.info,  Node: connector-odbc-examples-programming-vb-dao,  Next: connector-odbc-examples-programming-vb-rdo,  Prev: connector-odbc-examples-programming-vb-ado,  Up: connector-odbc-examples-programming-vb

20.1.5.13 DAO: `rs.addNew', `rs.update', and Scrolling
......................................................

The following DAO (Data Access Objects) example creates a table
`my_dao' and demonstrates the use of `rs.addNew', `rs.update', and
result set scrolling.

     Private Sub myodbc_dao_Click()

     Dim ws As Workspace
     Dim conn As Connection
     Dim queryDef As queryDef
     Dim str As String

     'connect to MySQL using MySQL ODBC 3.51 Driver
     Set ws = DBEngine.CreateWorkspace("", "venu", "venu", dbUseODBC)
     str = "odbc;DRIVER={MySQL ODBC 3.51 Driver};"_
     & "SERVER=localhost;"_
     & " DATABASE=test;"_
     & "UID=venu;PWD=venu; OPTION=3"
     Set conn = ws.OpenConnection("test", dbDriverNoPrompt, False, str)

     'Create table my_dao
     Set queryDef = conn.CreateQueryDef("", "drop table if exists my_dao")
     queryDef.Execute

     Set queryDef = conn.CreateQueryDef("", "create table my_dao(Id INT AUTO_INCREMENT PRIMARY KEY, " _
     & "Ts TIMESTAMP(14) NOT NULL, Name varchar(20), Id2 INT)")
     queryDef.Execute

     'Insert new records using rs.addNew
     Set rs = conn.OpenRecordset("my_dao")
     Dim i As Integer

     For i = 10 To 15
     rs.AddNew
     rs!Name = "insert record" & i
     rs!Id2 = i
     rs.Update
     Next i
     rs.Close

     'rs update..
     Set rs = conn.OpenRecordset("my_dao")
     rs.Edit
     rs!Name = "updated-string"
     rs.Update
     rs.Close

     'fetch the table back...
     Set rs = conn.OpenRecordset("my_dao", dbOpenDynamic)
     str = "Results:"
     rs.MoveFirst
     While Not rs.EOF
     str = " " & rs!Id & " , " & rs!Name & ", " & rs!Ts & ", " & rs!Id2
     Debug.Print "DATA:" & str
     rs.MoveNext
     Wend

     'rs Scrolling
     rs.MoveFirst
     str = " FIRST ROW: " & rs!Id & " , " & rs!Name & ", " & rs!Ts & ", " & rs!Id2
     Debug.Print str

     rs.MoveLast
     str = " LAST ROW: " & rs!Id & " , " & rs!Name & ", " & rs!Ts & ", " & rs!Id2
     Debug.Print str

     rs.MovePrevious
     str = " LAST-1 ROW: " & rs!Id & " , " & rs!Name & ", " & rs!Ts & ", " & rs!Id2
     Debug.Print str

     'free all resources
     rs.Close
     queryDef.Close
     conn.Close
     ws.Close

     End Sub


File: manual.info,  Node: connector-odbc-examples-programming-vb-rdo,  Prev: connector-odbc-examples-programming-vb-dao,  Up: connector-odbc-examples-programming-vb

20.1.5.14 RDO: `rs.addNew' and `rs.update'
..........................................

The following RDO (Remote Data Objects) example creates a table
`my_rdo' and demonstrates the use of `rs.addNew' and `rs.update'.

     Dim rs As rdoResultset
     Dim cn As New rdoConnection
     Dim cl As rdoColumn
     Dim SQL As String

     'cn.Connect = "DSN=test;"
     cn.Connect = "DRIVER={MySQL ODBC 3.51 Driver};"_
     & "SERVER=localhost;"_
     & " DATABASE=test;"_
     & "UID=venu;PWD=venu; OPTION=3"

     cn.CursorDriver = rdUseOdbc
     cn.EstablishConnection rdDriverPrompt

     'drop table my_rdo
     SQL = "drop table if exists my_rdo"
     cn.Execute SQL, rdExecDirect

     'create table my_rdo
     SQL = "create table my_rdo(id int, name varchar(20))"
     cn.Execute SQL, rdExecDirect

     'insert - direct
     SQL = "insert into my_rdo values (100,'venu')"
     cn.Execute SQL, rdExecDirect

     SQL = "insert into my_rdo values (200,'MySQL')"
     cn.Execute SQL, rdExecDirect

     'rs insert
     SQL = "select * from my_rdo"
     Set rs = cn.OpenResultset(SQL, rdOpenStatic, rdConcurRowVer, rdExecDirect)
     rs.AddNew
     rs!id = 300
     rs!Name = "Insert1"
     rs.Update
     rs.Close

     'rs insert
     SQL = "select * from my_rdo"
     Set rs = cn.OpenResultset(SQL, rdOpenStatic, rdConcurRowVer, rdExecDirect)
     rs.AddNew
     rs!id = 400
     rs!Name = "Insert 2"
     rs.Update
     rs.Close

     'rs update
     SQL = "select * from my_rdo"
     Set rs = cn.OpenResultset(SQL, rdOpenStatic, rdConcurRowVer, rdExecDirect)
     rs.Edit
     rs!id = 999
     rs!Name = "updated"
     rs.Update
     rs.Close

     'fetch back...
     SQL = "select * from my_rdo"
     Set rs = cn.OpenResultset(SQL, rdOpenStatic, rdConcurRowVer, rdExecDirect)
     Do Until rs.EOF
     For Each cl In rs.rdoColumns
     Debug.Print cl.Value,
     Next
     rs.MoveNext
     Debug.Print
     Loop
     Debug.Print "Row count="; rs.RowCount

     'close
     rs.Close
     cn.Close

     End Sub


File: manual.info,  Node: connector-odbc-examples-programming-net,  Prev: connector-odbc-examples-programming-vb,  Up: connector-odbc-examples-programming

20.1.5.15 Using Connector/ODBC with .NET
........................................

* Menu:

* connector-odbc-examples-programming-net-csharp::  Using Connector/ODBC with ODBC.NET and C# (C sharp)
* connector-odbc-examples-programming-net-vb::  Using Connector/ODBC with ODBC.NET and Visual Basic

This section contains simple examples that demonstrate the use of
Connector/ODBC drivers with ODBC.NET.


File: manual.info,  Node: connector-odbc-examples-programming-net-csharp,  Next: connector-odbc-examples-programming-net-vb,  Prev: connector-odbc-examples-programming-net,  Up: connector-odbc-examples-programming-net

20.1.5.16 Using Connector/ODBC with ODBC.NET and C# (C sharp)
.............................................................

The following sample creates a table `my_odbc_net' and demonstrates its
use in C#.

     /**
      * @sample    : mycon.cs
      * @purpose   : Demo sample for ODBC.NET using Connector/ODBC
      * @author    : Venu, <myodbc@lists.mysql.com>
      *
      * (C) Copyright MySQL AB, 1995-2006
      *
      **/

     /* build command
      *
      *  csc /t:exe
      *      /out:mycon.exe mycon.cs
      *      /r:Microsoft.Data.Odbc.dll
      */

     using Console = System.Console;
     using Microsoft.Data.Odbc;

     namespace myodbc3
     {
       class mycon
       {
         static void Main(string[] args)
         {
           try
             {
               //Connection string for Connector/ODBC 3.51
               string MyConString = "DRIVER={MySQL ODBC 3.51 Driver};" +
                 "SERVER=localhost;" +
                 "DATABASE=test;" +
                 "UID=venu;" +
                 "PASSWORD=venu;" +
                 "OPTION=3";

               //Connect to MySQL using Connector/ODBC
               OdbcConnection MyConnection = new OdbcConnection(MyConString);
               MyConnection.Open();

               Console.WriteLine("\n !!! success, connected successfully !!!\n");

               //Display connection information
               Console.WriteLine("Connection Information:");
               Console.WriteLine("\tConnection String:" +
                                 MyConnection.ConnectionString);
               Console.WriteLine("\tConnection Timeout:" +
                                 MyConnection.ConnectionTimeout);
               Console.WriteLine("\tDatabase:" +
                                 MyConnection.Database);
               Console.WriteLine("\tDataSource:" +
                                 MyConnection.DataSource);
               Console.WriteLine("\tDriver:" +
                                 MyConnection.Driver);
               Console.WriteLine("\tServerVersion:" +
                                 MyConnection.ServerVersion);

               //Create a sample table
               OdbcCommand MyCommand =
                 new OdbcCommand("DROP TABLE IF EXISTS my_odbc_net",
                                 MyConnection);
               MyCommand.ExecuteNonQuery();
               MyCommand.CommandText =
                 "CREATE TABLE my_odbc_net(id int, name varchar(20), idb bigint)";
               MyCommand.ExecuteNonQuery();

               //Insert
               MyCommand.CommandText =
                 "INSERT INTO my_odbc_net VALUES(10,'venu', 300)";
               Console.WriteLine("INSERT, Total rows affected:" +
                                 MyCommand.ExecuteNonQuery());;

               //Insert
               MyCommand.CommandText =
                 "INSERT INTO my_odbc_net VALUES(20,'mysql',400)";
               Console.WriteLine("INSERT, Total rows affected:" +
                                 MyCommand.ExecuteNonQuery());

               //Insert
               MyCommand.CommandText =
                 "INSERT INTO my_odbc_net VALUES(20,'mysql',500)";
               Console.WriteLine("INSERT, Total rows affected:" +
                                 MyCommand.ExecuteNonQuery());

               //Update
               MyCommand.CommandText =
                 "UPDATE my_odbc_net SET id=999 WHERE id=20";
               Console.WriteLine("Update, Total rows affected:" +
                                 MyCommand.ExecuteNonQuery());

               //COUNT(*)
               MyCommand.CommandText =
                 "SELECT COUNT(*) as TRows FROM my_odbc_net";
               Console.WriteLine("Total Rows:" +
                                 MyCommand.ExecuteScalar());

               //Fetch
               MyCommand.CommandText = "SELECT * FROM my_odbc_net";
               OdbcDataReader MyDataReader;
               MyDataReader =  MyCommand.ExecuteReader();
               while (MyDataReader.Read())
                 {
                   if(string.Compare(MyConnection.Driver,"myodbc3.dll") == 0) {
                     //Supported only by Connector/ODBC 3.51
                     Console.WriteLine("Data:" + MyDataReader.GetInt32(0) + " " +
                                       MyDataReader.GetString(1) + " " +
                                       MyDataReader.GetInt64(2));
                   }
                   else {
                     //BIGINTs not supported by Connector/ODBC
                     Console.WriteLine("Data:" + MyDataReader.GetInt32(0) + " " +
                                       MyDataReader.GetString(1) + " " +
                                       MyDataReader.GetInt32(2));
                   }
                 }

               //Close all resources
               MyDataReader.Close();
               MyConnection.Close();
             }
           catch (OdbcException MyOdbcException) //Catch any ODBC exception ..
             {
               for (int i=0; i < MyOdbcException.Errors.Count; i++)
                 {
                   Console.Write("ERROR #" + i + "\n" +
                                 "Message: " +
                                 MyOdbcException.Errors[i].Message + "\n" +
                                 "Native: " +
                                 MyOdbcException.Errors[i].NativeError.ToString() + "\n" +
                                 "Source: " +
                                 MyOdbcException.Errors[i].Source + "\n" +
                                 "SQL: " +
                                 MyOdbcException.Errors[i].SQLState + "\n");
                 }
             }
         }
       }
     }


File: manual.info,  Node: connector-odbc-examples-programming-net-vb,  Prev: connector-odbc-examples-programming-net-csharp,  Up: connector-odbc-examples-programming-net

20.1.5.17 Using Connector/ODBC with ODBC.NET and Visual Basic
.............................................................

The following sample creates a table `my_vb_net' and demonstrates the
use in VB.

     ' @sample    : myvb.vb
     ' @purpose   : Demo sample for ODBC.NET using Connector/ODBC
     ' @author    : Venu, <myodbc@lists.mysql.com>
     '
     ' (C) Copyright MySQL AB, 1995-2006
     '
     '

     '
     ' build command
     '
     ' vbc /target:exe
     '     /out:myvb.exe
     '     /r:Microsoft.Data.Odbc.dll
     '     /r:System.dll
     '     /r:System.Data.dll
     '

     Imports Microsoft.Data.Odbc
     Imports System

     Module myvb
       Sub Main()
         Try

           'Connector/ODBC 3.51 connection string
           Dim MyConString As String = "DRIVER={MySQL ODBC 3.51 Driver};" & _
           "SERVER=localhost;" & _
           "DATABASE=test;" & _
           "UID=venu;" & _
           "PASSWORD=venu;" & _
           "OPTION=3;"

           'Connection
           Dim MyConnection As New OdbcConnection(MyConString)
           MyConnection.Open()

           Console.WriteLine("Connection State::" & MyConnection.State.ToString)

           'Drop
           Console.WriteLine("Dropping table")
           Dim MyCommand As New OdbcCommand()
           MyCommand.Connection = MyConnection
           MyCommand.CommandText = "DROP TABLE IF EXISTS my_vb_net"
           MyCommand.ExecuteNonQuery()

           'Create
           Console.WriteLine("Creating....")
           MyCommand.CommandText = "CREATE TABLE my_vb_net(id int, name varchar(30))"
           MyCommand.ExecuteNonQuery()

           'Insert
           MyCommand.CommandText = "INSERT INTO my_vb_net VALUES(10,'venu')"
           Console.WriteLine("INSERT, Total rows affected:" & _
           MyCommand.ExecuteNonQuery())

           'Insert
           MyCommand.CommandText = "INSERT INTO my_vb_net VALUES(20,'mysql')"
           Console.WriteLine("INSERT, Total rows affected:" & _
           MyCommand.ExecuteNonQuery())

           'Insert
           MyCommand.CommandText = "INSERT INTO my_vb_net VALUES(20,'mysql')"
           Console.WriteLine("INSERT, Total rows affected:" & _
           MyCommand.ExecuteNonQuery())

           'Insert
           MyCommand.CommandText = "INSERT INTO my_vb_net(id) VALUES(30)"
           Console.WriteLine("INSERT, Total rows affected:" & _
                             MyCommand.ExecuteNonQuery())

           'Update
           MyCommand.CommandText = "UPDATE my_vb_net SET id=999 WHERE id=20"
           Console.WriteLine("Update, Total rows affected:" & _
           MyCommand.ExecuteNonQuery())

           'COUNT(*)
           MyCommand.CommandText = "SELECT COUNT(*) as TRows FROM my_vb_net"
           Console.WriteLine("Total Rows:" & MyCommand.ExecuteScalar())

           'Select
           Console.WriteLine("Select * FROM my_vb_net")
           MyCommand.CommandText = "SELECT * FROM my_vb_net"
           Dim MyDataReader As OdbcDataReader
           MyDataReader = MyCommand.ExecuteReader
           While MyDataReader.Read
             If MyDataReader("name") Is DBNull.Value Then
               Console.WriteLine("id = " & _
               CStr(MyDataReader("id")) & "  name = " & _
               "NULL")
             Else
               Console.WriteLine("id = " & _
               CStr(MyDataReader("id")) & "  name = " & _
               CStr(MyDataReader("name")))
             End If
           End While

           'Catch ODBC Exception
         Catch MyOdbcException As OdbcException
           Dim i As Integer
           Console.WriteLine(MyOdbcException.ToString)

           'Catch program exception
         Catch MyException As Exception
           Console.WriteLine(MyException.ToString)
         End Try
       End Sub


File: manual.info,  Node: connector-odbc-reference,  Next: connector-odbc-usagenotes,  Prev: connector-odbc-examples,  Up: connector-odbc

20.1.6 Connector/ODBC Reference
-------------------------------

* Menu:

* connector-odbc-reference-api::  Connector/ODBC API Reference
* connector-odbc-reference-datatypes::  Connector/ODBC Data Types
* connector-odbc-reference-errorcodes::  Connector/ODBC Error Codes

This section provides reference material for the Connector/ODBC API,
showing supported functions and methods, supported MySQL column types
and the corresponding native type in Connector/ODBC, and the error
codes returned by Connector/ODBC when a fault occurs.


File: manual.info,  Node: connector-odbc-reference-api,  Next: connector-odbc-reference-datatypes,  Prev: connector-odbc-reference,  Up: connector-odbc-reference

20.1.6.1 Connector/ODBC API Reference
.....................................

This section summarizes ODBC routines, categorized by functionality.

For the complete ODBC API reference, please refer to the ODBC
Programmer's Reference at
`http://msdn.microsoft.com/en-us/library/ms714177.aspx'.

An application can call `SQLGetInfo' function to obtain conformance
information about Connector/ODBC. To obtain information about support
for a specific function in the driver, an application can call
`SQLGetFunctions'.

*Note*:

For backward compatibility, the Connector/ODBC 3.51 driver supports all
deprecated functions.

The following tables list Connector/ODBC API calls grouped by task:

*Connecting to a data source*

Function name       C/ODBC    Standard  Purpose
                    3.51                
`SQLAllocHandle'    Yes       ISO 92    Obtains an environment, connection,
                                        statement, or descriptor handle.
`SQLConnect'        Yes       ISO 92    Connects to a specific driver by
                                        data source name, user ID, and
                                        password.
`SQLDriverConnect'  Yes       ODBC      Connects to a specific driver by
                                        connection string or requests that
                                        the Driver Manager and driver
                                        display connection dialog boxes for
                                        the user.
`SQLAllocEnv'       Yes       DeprecatedObtains an environment handle
                                        allocated from driver.
`SQLAllocConnect'   Yes       DeprecatedObtains a connection handle

*Obtaining information about a driver and data source*

Function name       C/ODBC    Standard  Purpose
                    3.51                
`SQLDataSources'    No        ISO 92    Returns the list of available data
                                        sources, handled by the Driver
                                        Manager
`SQLDrivers'        No        ODBC      Returns the list of installed
                                        drivers and their attributes,
                                        handles by Driver Manager
`SQLGetInfo'        Yes       ISO 92    Returns information about a
                                        specific driver and data source.
`SQLGetFunctions'   Yes       ISO 92    Returns supported driver functions.
`SQLGetTypeInfo'    Yes       ISO 92    Returns information about supported
                                        data types.

*Setting and retrieving driver attributes*

Function name       C/ODBC    Standard  Purpose
                    3.51                
`SQLSetConnectAttr' Yes       ISO 92    Sets a connection attribute.
`SQLGetConnectAttr' Yes       ISO 92    Returns the value of a connection
                                        attribute.
`SQLSetConnectOption'Yes       DeprecatedSets a connection option
`SQLGetConnectOption'Yes       DeprecatedReturns the value of a connection
                                        option
`SQLSetEnvAttr'     Yes       ISO 92    Sets an environment attribute.
`SQLGetEnvAttr'     Yes       ISO 92    Returns the value of an environment
                                        attribute.
`SQLSetStmtAttr'    Yes       ISO 92    Sets a statement attribute.
`SQLGetStmtAttr'    Yes       ISO 92    Returns the value of a statement
                                        attribute.
`SQLSetStmtOption'  Yes       DeprecatedSets a statement option
`SQLGetStmtOption'  Yes       DeprecatedReturns the value of a statement
                                        option

*Preparing SQL requests*

Function name       C/ODBC    Standard  Purpose
                    3.51                
`SQLAllocStmt'      Yes       DeprecatedAllocates a statement handle
`SQLPrepare'        Yes       ISO 92    Prepares an SQL statement for later
                                        execution.
`SQLBindParameter'  Yes       ODBC      Assigns storage for a parameter in
                                        an SQL statement.
`SQLGetCursorName'  Yes       ISO 92    Returns the cursor name associated
                                        with a statement handle.
`SQLSetCursorName'  Yes       ISO 92    Specifies a cursor name.
`SQLSetScrollOptions'Yes       ODBC      Sets options that control cursor
                                        behavior.

*Submitting requests*

Function name       C/ODBC    Standard  Purpose
                    3.51                
`SQLExecute'        Yes       ISO 92    Executes a prepared statement.
`SQLExecDirect'     Yes       ISO 92    Executes a statement
`SQLNativeSql'      Yes       ODBC      Returns the text of an SQL
                                        statement as translated by the
                                        driver.
`SQLDescribeParam'  Yes       ODBC      Returns the description for a
                                        specific parameter in a statement.
`SQLNumParams'      Yes       ISO 92    Returns the number of parameters in
                                        a statement.
`SQLParamData'      Yes       ISO 92    Used in conjunction with
                                        `SQLPutData' to supply parameter
                                        data at execution time. (Useful for
                                        long data values.)
`SQLPutData'        Yes       ISO 92    Sends part or all of a data value
                                        for a parameter. (Useful for long
                                        data values.)

*Retrieving results and information about results*

Function name       C/ODBC    Standard  Purpose
                    3.51                
`SQLRowCount'       Yes       ISO 92    Returns the number of rows affected
                                        by an insert, update, or delete
                                        request.
`SQLNumResultCols'  Yes       ISO 92    Returns the number of columns in
                                        the result set.
`SQLDescribeCol'    Yes       ISO 92    Describes a column in the result
                                        set.
`SQLColAttribute'   Yes       ISO 92    Describes attributes of a column in
                                        the result set.
`SQLColAttributes'  Yes       DeprecatedDescribes attributes of a column in
                                        the result set.
`SQLFetch'          Yes       ISO 92    Returns multiple result rows.
`SQLFetchScroll'    Yes       ISO 92    Returns scrollable result rows.
`SQLExtendedFetch'  Yes       DeprecatedReturns scrollable result rows.
`SQLSetPos'         Yes       ODBC      Positions a cursor within a fetched
                                        block of data and enables an
                                        application to refresh data in the
                                        rowset or to update or delete data
                                        in the result set.
`SQLBulkOperations' Yes       ODBC      Performs bulk insertions and bulk
                                        bookmark operations, including
                                        update, delete, and fetch by
                                        bookmark.

*Retrieving error or diagnostic information*

Function name       C/ODBC    Standard  Purpose
                    3.51                
`SQLError'          Yes       DeprecatedReturns additional error or status
                                        information
`SQLGetDiagField'   Yes       ISO 92    Returns additional diagnostic
                                        information (a single field of the
                                        diagnostic data structure).
`SQLGetDiagRec'     Yes       ISO 92    Returns additional diagnostic
                                        information (multiple fields of the
                                        diagnostic data structure).

*Obtaining information about the data source's system tables (catalog
functions) item*

Function name       C/ODBC    Standard  Purpose
                    3.51                
`SQLColumnPrivileges'Yes       ODBC      Returns a list of columns and
                                        associated privileges for one or
                                        more tables.
`SQLColumns'        Yes       X/Open    Returns the list of column names in
                                        specified tables.
`SQLForeignKeys'    Yes       ODBC      Returns a list of column names that
                                        make up foreign keys, if they exist
                                        for a specified table.
`SQLPrimaryKeys'    Yes       ODBC      Returns the list of column names
                                        that make up the primary key for a
                                        table.
`SQLSpecialColumns' Yes       X/Open    Returns information about the
                                        optimal set of columns that uniquely
                                        identifies a row in a specified
                                        table, or the columns that are
                                        automatically updated when any
                                        value in the row is updated by a
                                        transaction.
`SQLStatistics'     Yes       ISO 92    Returns statistics about a single
                                        table and the list of indexes
                                        associated with the table.
`SQLTablePrivileges'Yes       ODBC      Returns a list of tables and the
                                        privileges associated with each
                                        table.
`SQLTables'         Yes       X/Open    Returns the list of table names
                                        stored in a specific data source.

*Performing transactions*

Function name       C/ODBC    Standard  Purpose
                    3.51                
`SQLTransact'       Yes       DeprecatedCommits or rolls back a transaction
`SQLEndTran'        Yes       ISO 92    Commits or rolls back a transaction.

*Terminating a statement*

Function name       C/ODBC    Standard  Purpose
                    3.51                
`SQLFreeStmt'       Yes       ISO 92    Ends statement processing, discards
                                        pending results, and, optionally,
                                        frees all resources associated with
                                        the statement handle.
`SQLCloseCursor'    Yes       ISO 92    Closes a cursor that has been
                                        opened on a statement handle.
`SQLCancel'         Yes       ISO 92    Cancels an SQL statement.

*Terminating a connection*

Function name       C/ODBC    Standard  Purpose
                    3.51                
`SQLDisconnect'     Yes       ISO 92    Closes the connection.
`SQLFreeHandle'     Yes       ISO 92    Releases an environment,
                                        connection, statement, or
                                        descriptor handle.
`SQLFreeConnect'    Yes       DeprecatedReleases connection handle
`SQLFreeEnv'        Yes       DeprecatedReleases an environment handle


File: manual.info,  Node: connector-odbc-reference-datatypes,  Next: connector-odbc-reference-errorcodes,  Prev: connector-odbc-reference-api,  Up: connector-odbc-reference

20.1.6.2 Connector/ODBC Data Types
..................................

The following table illustrates how driver maps the server data types
to default SQL and C data types.

Native Value             SQL Type                 C Type
`bigint unsigned'        `SQL_BIGINT'             `SQL_C_UBIGINT'
`bigint'                 `SQL_BIGINT'             `SQL_C_SBIGINT'
`bit'                    `SQL_BIT'                `SQL_C_BIT'
`bit'                    `SQL_CHAR'               `SQL_C_CHAR'
`blob'                   `SQL_LONGVARBINARY'      `SQL_C_BINARY'
`bool'                   `SQL_CHAR'               `SQL_C_CHAR'
`char'                   `SQL_CHAR'               `SQL_C_CHAR'
`date'                   `SQL_DATE'               `SQL_C_DATE'
`datetime'               `SQL_TIMESTAMP'          `SQL_C_TIMESTAMP'
`decimal'                `SQL_DECIMAL'            `SQL_C_CHAR'
`double precision'       `SQL_DOUBLE'             `SQL_C_DOUBLE'
`double'                 `SQL_FLOAT'              `SQL_C_DOUBLE'
`enum'                   `SQL_VARCHAR'            `SQL_C_CHAR'
`float'                  `SQL_REAL'               `SQL_C_FLOAT'
`int unsigned'           `SQL_INTEGER'            `SQL_C_ULONG'
`int'                    `SQL_INTEGER'            `SQL_C_SLONG'
`integer unsigned'       `SQL_INTEGER'            `SQL_C_ULONG'
`integer'                `SQL_INTEGER'            `SQL_C_SLONG'
`long varbinary'         `SQL_LONGVARBINARY'      `SQL_C_BINARY'
`long varchar'           `SQL_LONGVARCHAR'        `SQL_C_CHAR'
`longblob'               `SQL_LONGVARBINARY'      `SQL_C_BINARY'
`longtext'               `SQL_LONGVARCHAR'        `SQL_C_CHAR'
`mediumblob'             `SQL_LONGVARBINARY'      `SQL_C_BINARY'
`mediumint unsigned'     `SQL_INTEGER'            `SQL_C_ULONG'
`mediumint'              `SQL_INTEGER'            `SQL_C_SLONG'
`mediumtext'             `SQL_LONGVARCHAR'        `SQL_C_CHAR'
`numeric'                `SQL_NUMERIC'            `SQL_C_CHAR'
`real'                   `SQL_FLOAT'              `SQL_C_DOUBLE'
`set'                    `SQL_VARCHAR'            `SQL_C_CHAR'
`smallint unsigned'      `SQL_SMALLINT'           `SQL_C_USHORT'
`smallint'               `SQL_SMALLINT'           `SQL_C_SSHORT'
`text'                   `SQL_LONGVARCHAR'        `SQL_C_CHAR'
`time'                   `SQL_TIME'               `SQL_C_TIME'
`timestamp'              `SQL_TIMESTAMP'          `SQL_C_TIMESTAMP'
`tinyblob'               `SQL_LONGVARBINARY'      `SQL_C_BINARY'
`tinyint unsigned'       `SQL_TINYINT'            `SQL_C_UTINYINT'
`tinyint'                `SQL_TINYINT'            `SQL_C_STINYINT'
`tinytext'               `SQL_LONGVARCHAR'        `SQL_C_CHAR'
`varchar'                `SQL_VARCHAR'            `SQL_C_CHAR'
`year'                   `SQL_SMALLINT'           `SQL_C_SHORT'


File: manual.info,  Node: connector-odbc-reference-errorcodes,  Prev: connector-odbc-reference-datatypes,  Up: connector-odbc-reference

20.1.6.3 Connector/ODBC Error Codes
...................................

The following tables lists the error codes returned by the driver apart
from the server errors.

Native  SQLSTATE 2   SQLSTATE 3   Error Message
Code                              
500     01000        01000        General warning
501     01004        01004        String data, right truncated
502     01S02        01S02        Option value changed
503     01S03        01S03        No rows updated/deleted
504     01S04        01S04        More than one row updated/deleted
505     01S06        01S06        Attempt to fetch before the result set
                                  returned the first row set
506     07001        07002        `SQLBindParameter' not used for all
                                  parameters
507     07005        07005        Prepared statement not a
                                  cursor-specification
508     07009        07009        Invalid descriptor index
509     08002        08002        Connection name in use
510     08003        08003        Connection does not exist
511     24000        24000        Invalid cursor state
512     25000        25000        Invalid transaction state
513     25S01        25S01        Transaction state unknown
514     34000        34000        Invalid cursor name
515     S1000        HY000        General driver defined error
516     S1001        HY001        Memory allocation error
517     S1002        HY002        Invalid column number
518     S1003        HY003        Invalid application buffer type
519     S1004        HY004        Invalid SQL data type
520     S1009        HY009        Invalid use of null pointer
521     S1010        HY010        Function sequence error
522     S1011        HY011        Attribute can not be set now
523     S1012        HY012        Invalid transaction operation code
524     S1013        HY013        Memory management error
525     S1015        HY015        No cursor name available
526     S1024        HY024        Invalid attribute value
527     S1090        HY090        Invalid string or buffer length
528     S1091        HY091        Invalid descriptor field identifier
529     S1092        HY092        Invalid attribute/option identifier
530     S1093        HY093        Invalid parameter number
531     S1095        HY095        Function type out of range
532     S1106        HY106        Fetch type out of range
533     S1117        HY117        Row value out of range
534     S1109        HY109        Invalid cursor position
535     S1C00        HYC00        Optional feature not implemented
0       21S01        21S01        Column count does not match value count
0       23000        23000        Integrity constraint violation
0       42000        42000        Syntax error or access violation
0       42S02        42S02        Base table or view not found
0       42S12        42S12        Index not found
0       42S21        42S21        Column already exists
0       42S22        42S22        Column not found
0       08S01        08S01        Communication link failure


File: manual.info,  Node: connector-odbc-usagenotes,  Next: connector-odbc-support,  Prev: connector-odbc-reference,  Up: connector-odbc

20.1.7 Connector/ODBC Notes and Tips
------------------------------------

* Menu:

* connector-odbc-usagenotes-functionality::  Connector/ODBC General Functionality
* connector-odbc-usagenotes-apptips::  Connector/ODBC Application Specific Tips
* connector-odbc-errors::        Connector/ODBC Errors and Resolutions (FAQ)

Here are some common notes and tips for using Connector/ODBC within
different environments, applications and tools. The notes provided here
are based on the experiences of Connector/ODBC developers and users.


File: manual.info,  Node: connector-odbc-usagenotes-functionality,  Next: connector-odbc-usagenotes-apptips,  Prev: connector-odbc-usagenotes,  Up: connector-odbc-usagenotes

20.1.7.1 Connector/ODBC General Functionality
.............................................

* Menu:

* connector-odbc-usagenotes-functionality-last-insert-id::  Obtaining Auto-Increment Values
* connector-odbc-usagenotes-functionality-dynamic-cursor::  Dynamic Cursor Support
* connector-odbc-usagenotes-functionality-performance::  Connector/ODBC Performance
* connector-odbc-usagenotes-functionality-query-timeout::  Setting ODBC Query Timeout in Windows

This section provides help with common queries and areas of
functionality in MySQL and how to use them with Connector/ODBC.


File: manual.info,  Node: connector-odbc-usagenotes-functionality-last-insert-id,  Next: connector-odbc-usagenotes-functionality-dynamic-cursor,  Prev: connector-odbc-usagenotes-functionality,  Up: connector-odbc-usagenotes-functionality

20.1.7.2 Obtaining Auto-Increment Values
........................................

Obtaining the value of column that uses `AUTO_INCREMENT' after an *Note
`INSERT': insert. statement can be achieved in a number of different
ways. To obtain the value immediately after an *Note `INSERT': insert,
use a *Note `SELECT': select. query with the `LAST_INSERT_ID()'
function.

For example, using Connector/ODBC you would execute two separate
statements, the *Note `INSERT': insert.  statement and the *Note
`SELECT': select. query to obtain the auto-increment value.

     INSERT INTO tbl (auto,text) VALUES(NULL,'text');
     SELECT LAST_INSERT_ID();

If you do not require the value within your application, but do require
the value as part of another *Note `INSERT': insert, the entire process
can be handled by executing the following statements:

     INSERT INTO tbl (auto,text) VALUES(NULL,'text');
     INSERT INTO tbl2 (id,text) VALUES(LAST_INSERT_ID(),'text');

Certain ODBC applications (including Delphi and Access) may have
trouble obtaining the auto-increment value using the previous examples.
In this case, try the following statement as an alternative:

     SELECT * FROM tbl WHERE auto IS NULL;

This alternative method requires that `sql_auto_is_null' variable is
not set to 0. See *Note server-system-variables::.

See also *Note getting-unique-id::.


File: manual.info,  Node: connector-odbc-usagenotes-functionality-dynamic-cursor,  Next: connector-odbc-usagenotes-functionality-performance,  Prev: connector-odbc-usagenotes-functionality-last-insert-id,  Up: connector-odbc-usagenotes-functionality

20.1.7.3 Dynamic Cursor Support
...............................

Support for the `dynamic cursor' is provided in Connector/ODBC 3.51,
but dynamic cursors are not enabled by default. You can enable this
function within Windows by selecting the `Enable Dynamic Cursor' check
box within the ODBC Data Source Administrator.

On other platforms, you can enable the dynamic cursor by adding `32' to
the `OPTION' value when creating the DSN.


File: manual.info,  Node: connector-odbc-usagenotes-functionality-performance,  Next: connector-odbc-usagenotes-functionality-query-timeout,  Prev: connector-odbc-usagenotes-functionality-dynamic-cursor,  Up: connector-odbc-usagenotes-functionality

20.1.7.4 Connector/ODBC Performance
...................................

The Connector/ODBC driver has been optimized to provide very fast
performance. If you experience problems with the performance of
Connector/ODBC, or notice a large amount of disk activity for simple
queries, there are a number of aspects you should check:

   * Ensure that `ODBC Tracing' is not enabled. With tracing enabled, a
     lot of information is recorded in the tracing file by the ODBC
     Manager. You can check, and disable, tracing within Windows using
     the `Tracing' panel of the ODBC Data Source Administrator. Within
     Mac OS X, check the `Tracing' panel of ODBC Administrator. See
     *Note connector-odbc-configuration-trace::.

   * Make sure you are using the standard version of the driver, and
     not the debug version. The debug version includes additional
     checks and reporting measures.

   * Disable the Connector/ODBC driver trace and query logs.  These
     options are enabled for each DSN, so make sure to examine only the
     DSN that you are using in your application. Within Windows, you
     can disable the Connector/ODBC and query logs by modifying the DSN
     configuration. Within Mac OS X and Unix, ensure that the driver
     trace (option value 4) and query logging (option value 524288) are
     not enabled.


File: manual.info,  Node: connector-odbc-usagenotes-functionality-query-timeout,  Prev: connector-odbc-usagenotes-functionality-performance,  Up: connector-odbc-usagenotes-functionality

20.1.7.5 Setting ODBC Query Timeout in Windows
..............................................

For more information on how to set the query timeout on Microsoft
Windows when executing queries through an ODBC connection, read the
Microsoft knowledgebase document at
`http://support.microsoft.com/default.aspx?scid=kb%3Ben-us%3B153756'.


File: manual.info,  Node: connector-odbc-usagenotes-apptips,  Next: connector-odbc-errors,  Prev: connector-odbc-usagenotes-functionality,  Up: connector-odbc-usagenotes

20.1.7.6 Connector/ODBC Application Specific Tips
.................................................

* Menu:

* connector-odbc-usagenotes-apptips-microsoft::  Using Connector/ODBC with Microsoft Applications
* connector-odbc-usagenotes-apptips-borland::  Using Connector/ODBC with Borland Applications
* connector-odbc-usagenotes-apptips-coldfusion::  Using Connector/ODBC with ColdFusion
* connector-odbc-usagenotes-apptips-openoffice::  Using Connector/ODBC with OpenOffice.org
* connector-odbc-usagenotes-apptips-sambarserver::  Using Connector/ODBC with Sambar Server
* connector-odbc-usagenotes-apptips-datajunction::  Using Connector/ODBC with Pervasive Software DataJunction
* connector-odbc-usagenotes-apptips-vision::  Using Connector/ODBC with SunSystems Vision

Most programs should work with Connector/ODBC, but for each of those
listed here, there are specific notes and tips to improve or enhance
the way you work with Connector/ODBC and these applications.

With all applications you should ensure that you are using the latest
Connector/ODBC drivers, ODBC Manager and any supporting libraries and
interfaces used by your application. For example, on Windows, using the
latest version of Microsoft Data Access Components (MDAC) will improve
the compatibility with ODBC in general, and with the Connector/ODBC
driver.


File: manual.info,  Node: connector-odbc-usagenotes-apptips-microsoft,  Next: connector-odbc-usagenotes-apptips-borland,  Prev: connector-odbc-usagenotes-apptips,  Up: connector-odbc-usagenotes-apptips

20.1.7.7 Using Connector/ODBC with Microsoft Applications
.........................................................

* Menu:

* connector-odbc-usagenotes-apptips-microsoft-access::  Microsoft Access
* connector-odbc-usagenotes-apptips-microsoft-excel::  Microsoft Excel and Column Types
* connector-odbc-usagenotes-apptips-microsoft-visualbasic::  Microsoft Visual Basic
* connector-odbc-usagenotes-apptips-microsoft-visualinterdev::  Microsoft Visual InterDev
* connector-odbc-usagenotes-apptips-microsoft-visualobjects::  Visual Objects
* connector-odbc-usagenotes-apptips-microsoft-ado::  Microsoft ADO
* connector-odbc-usagenotes-apptips-microsoft-asp::  Using Connector/ODBC with Active Server Pages (ASP)
* connector-odbc-usagenotes-apptips-microsoft-vb-asp::  Using Connector/ODBC with Visual Basic (ADO, DAO and RDO) and ASP

The majority of Microsoft applications have been tested with
Connector/ODBC, including Microsoft Office, Microsoft Access and the
various programming languages supported within ASP and Microsoft Visual
Studio.


File: manual.info,  Node: connector-odbc-usagenotes-apptips-microsoft-access,  Next: connector-odbc-usagenotes-apptips-microsoft-excel,  Prev: connector-odbc-usagenotes-apptips-microsoft,  Up: connector-odbc-usagenotes-apptips-microsoft

20.1.7.8 Microsoft Access
.........................

To improve the integration between Microsoft Access and MySQL through
Connector/ODBC:

   * For all versions of Access, you should enable the Connector/ODBC
     `Return matching rows' option. For Access 2.0, you should
     additionally enable the `Simulate ODBC 1.0' option.

   * You should have a *Note `TIMESTAMP': datetime. column in all
     tables that you want to be able to update. For maximum
     portability, do not use a length specification in the column
     declaration (which is unsupported within MySQL in versions earlier
     than 4.1).

   * You should have a primary key in each MySQL table you want to use
     with Access. If not, new or updated rows may show up as
     `#DELETED#'.

   * Use only *Note `DOUBLE': numeric-types. float fields. Access fails
     when comparing with single-precision floats. The symptom usually
     is that new or updated rows may show up as `#DELETED#' or that you
     cannot find or update rows.

   * If you are using Connector/ODBC to link to a table that has a
     *Note `BIGINT': numeric-types. column, the results are displayed
     as `#DELETED#'.  The work around solution is:

        * Have one more dummy column with *Note `TIMESTAMP': datetime.
          as the data type.

        * Select the `Change BIGINT columns to INT' option in the
          connection dialog in ODBC DSN Administrator.

        * Delete the table link from Access and re-create it.

     Old records may still display as `#DELETED#', but newly
     added/updated records are displayed properly.

   * If you still get the error `Another user has changed your data'
     after adding a *Note `TIMESTAMP': datetime. column, the following
     trick may help you:

     Do not use a `table' data sheet view.  Instead, create a form with
     the fields you want, and use that `form' data sheet view. You
     should set the `DefaultValue' property for the *Note `TIMESTAMP':
     datetime. column to `NOW()'. It may be a good idea to hide the
     *Note `TIMESTAMP': datetime. column from view so your users are
     not confused.

   * In some cases, Access may generate SQL statements that MySQL
     cannot understand. You can fix this by selecting
     `"Query|SQLSpecific|Pass-Through"' from the Access menu.

   * On Windows NT, Access reports *Note `BLOB': blob. columns as `OLE
     OBJECTS'. If you want to have `MEMO' columns instead, you should
     change *Note `BLOB': blob. columns to *Note `TEXT': blob. with
     *Note `ALTER TABLE': alter-table.

   * Access cannot always handle the MySQL *Note `DATE': datetime.
     column properly. If you have a problem with these, change the
     columns to *Note `DATETIME': datetime.

   * If you have in Access a column defined as `BYTE', Access tries to
     export this as *Note `TINYINT': numeric-types. instead of `TINYINT
     UNSIGNED'. This gives you problems if you have values larger than
     127 in the column.

   * If you have very large (long) tables in Access, it might take a
     very long time to open them. Or you might run low on virtual
     memory and eventually get an `ODBC Query Failed' error and the
     table cannot open.  To deal with this, select the following
     options:

        * Return Matching Rows (2)

        * Allow BIG Results (8).

     These add up to a value of 10 (`OPTION=10').

Some external articles and tips that may be useful when using Access,
ODBC and Connector/ODBC:

   * Read How to Trap ODBC Login Error Messages in Access
     (http://support.microsoft.com/support/kb/articles/Q124/9/01.asp?LN=EN-US&SD=gn&FR=0%3CP%3E)

   * Optimizing Access ODBC Applications

        * Optimizing for Client/Server Performance
          (http://support.microsoft.com/default.aspx?scid=kb;en-us;128808)

        * Tips for Converting Applications to Using ODBCDirect
          (http://support.microsoft.com/default.aspx?scid=kb;en-us;164481)

        * Tips for Optimizing Queries on Attached SQL Tables
          (http://support.microsoft.com/default.aspx?scid=kb;EN-US;q99321)

   * For a list of tools that can be used with Access and ODBC data
     sources, refer to http://www.mysql.com/portal/software/convertors/
     section for list of available tools.


File: manual.info,  Node: connector-odbc-usagenotes-apptips-microsoft-excel,  Next: connector-odbc-usagenotes-apptips-microsoft-visualbasic,  Prev: connector-odbc-usagenotes-apptips-microsoft-access,  Up: connector-odbc-usagenotes-apptips-microsoft

20.1.7.9 Microsoft Excel and Column Types
.........................................

If you have problems importing data into Microsoft Excel, particularly
numeric, date, and time values, this is probably because of a bug in
Excel, where the column type of the source data is used to determine
the data type when that data is inserted into a cell within the
worksheet. The result is that Excel incorrectly identifies the content
and this affects both the display format and the data when it is used
within calculations.

To address this issue, use the `CONCAT()' function in your queries. The
use of `CONCAT()' forces Excel to treat the value as a string, which
Excel will then parse and usually correctly identify the embedded
information.

However, even with this option, some data may be incorrectly formatted,
even though the source data remains unchanged.  Use the `Format Cells'
option within Excel to change the format of the displayed information.


File: manual.info,  Node: connector-odbc-usagenotes-apptips-microsoft-visualbasic,  Next: connector-odbc-usagenotes-apptips-microsoft-visualinterdev,  Prev: connector-odbc-usagenotes-apptips-microsoft-excel,  Up: connector-odbc-usagenotes-apptips-microsoft

20.1.7.10 Microsoft Visual Basic
................................

To be able to update a table, you must define a primary key for the
table.

Visual Basic with ADO cannot handle big integers. This means that some
queries like *Note `SHOW PROCESSLIST': show-processlist. do not work
properly. The fix is to use `OPTION=16384' in the ODBC connect string
or to select the `Change BIGINT columns to INT' option in the
Connector/ODBC connect screen.  You may also want to select the `Return
matching rows' option.


File: manual.info,  Node: connector-odbc-usagenotes-apptips-microsoft-visualinterdev,  Next: connector-odbc-usagenotes-apptips-microsoft-visualobjects,  Prev: connector-odbc-usagenotes-apptips-microsoft-visualbasic,  Up: connector-odbc-usagenotes-apptips-microsoft

20.1.7.11 Microsoft Visual InterDev
...................................

If you have a *Note `BIGINT': numeric-types. in your result, you may
get the error `[Microsoft][ODBC Driver Manager] Driver does not support
this parameter'. Try selecting the `Change BIGINT columns to INT'
option in the Connector/ODBC connect screen.


File: manual.info,  Node: connector-odbc-usagenotes-apptips-microsoft-visualobjects,  Next: connector-odbc-usagenotes-apptips-microsoft-ado,  Prev: connector-odbc-usagenotes-apptips-microsoft-visualinterdev,  Up: connector-odbc-usagenotes-apptips-microsoft

20.1.7.12 Visual Objects
........................

You should select the `Don't optimize column widths' option.


File: manual.info,  Node: connector-odbc-usagenotes-apptips-microsoft-ado,  Next: connector-odbc-usagenotes-apptips-microsoft-asp,  Prev: connector-odbc-usagenotes-apptips-microsoft-visualobjects,  Up: connector-odbc-usagenotes-apptips-microsoft

20.1.7.13 Microsoft ADO
.......................

When you are coding with the ADO API and Connector/ODBC, you need to
pay attention to some default properties that aren't supported by the
MySQL server. For example, using the `CursorLocation Property' as
`adUseServer' returns a result of -1 for the `RecordCount Property'. To
have the right value, you need to set this property to `adUseClient',
as shown in the VB code here:

     Dim myconn As New ADODB.Connection
     Dim myrs As New Recordset
     Dim mySQL As String
     Dim myrows As Long

     myconn.Open "DSN=MyODBCsample"
     mySQL = "SELECT * from user"
     myrs.Source = mySQL
     Set myrs.ActiveConnection = myconn
     myrs.CursorLocation = adUseClient
     myrs.Open
     myrows = myrs.RecordCount

     myrs.Close
     myconn.Close

Another workaround is to use a `SELECT COUNT(*)' statement for a
similar query to get the correct row count.

To find the number of rows affected by a specific SQL statement in ADO,
use the `RecordsAffected' property in the ADO execute method. For more
information on the usage of execute method, refer to
`http://msdn.microsoft.com/library/default.asp?url=/library/en-us/ado270/htm/mdmthcnnexecute.asp'.

For information, see ActiveX Data Objects(ADO) Frequently Asked
Questions
(http://support.microsoft.com/default.aspx?scid=kb;EN-US;q183606).


File: manual.info,  Node: connector-odbc-usagenotes-apptips-microsoft-asp,  Next: connector-odbc-usagenotes-apptips-microsoft-vb-asp,  Prev: connector-odbc-usagenotes-apptips-microsoft-ado,  Up: connector-odbc-usagenotes-apptips-microsoft

20.1.7.14 Using Connector/ODBC with Active Server Pages (ASP)
.............................................................

You should select the `Return matching rows' option in the DSN.

For more information about how to access MySQL through ASP using
Connector/ODBC, refer to the following articles:

   * Using MyODBC To Access Your MySQL Database Via ASP
     (http://www.devarticles.com/c/a/ASP/Using-MyODBC-To-Access-Your-MySQL-Database-Via-ASP/)

   * ASP and MySQL at DWAM.NT (http://www.dwam.net/mysql/asp_myodbc.asp)

A Frequently Asked Questions list for ASP can be found at
`http://support.microsoft.com/default.aspx?scid=/Support/ActiveServer/faq/data/adofaq.asp'.


File: manual.info,  Node: connector-odbc-usagenotes-apptips-microsoft-vb-asp,  Prev: connector-odbc-usagenotes-apptips-microsoft-asp,  Up: connector-odbc-usagenotes-apptips-microsoft

20.1.7.15 Using Connector/ODBC with Visual Basic (ADO, DAO and RDO) and ASP
...........................................................................

Some articles that may help with Visual Basic and ASP:

   * MySQL BLOB columns and Visual Basic 6
     (http://dev.mysql.com/tech-resources/articles/vb-blob-handling.html)
     by Mike Hillyer (<mike@openwin.org>).

   * How to map Visual basic data type to MySQL types
     (http://dev.mysql.com/tech-resources/articles/visual-basic-datatypes.html)
     by Mike Hillyer (<mike@openwin.org>).


File: manual.info,  Node: connector-odbc-usagenotes-apptips-borland,  Next: connector-odbc-usagenotes-apptips-coldfusion,  Prev: connector-odbc-usagenotes-apptips-microsoft,  Up: connector-odbc-usagenotes-apptips

20.1.7.16 Using Connector/ODBC with Borland Applications
........................................................

* Menu:

* connector-odbc-usagenotes-apptips-borland-builder::  Using Connector/ODBC with Borland Builder 4
* connector-odbc-usagenotes-apptips-borland-delphi::  Using Connector/ODBC with Delphi
* connector-odbc-usagenotes-apptips-borland-cppbuilder::  Using Connector/ODBC with C++ Builder

With all Borland applications where the Borland Database Engine (BDE)
is used, follow these steps to improve compatibility:

   * Update to BDE 3.2 or newer.

   * Enable the `Don't optimize column widths' option in the DSN.

   * Enabled the `Return matching rows' option in the DSN.


File: manual.info,  Node: connector-odbc-usagenotes-apptips-borland-builder,  Next: connector-odbc-usagenotes-apptips-borland-delphi,  Prev: connector-odbc-usagenotes-apptips-borland,  Up: connector-odbc-usagenotes-apptips-borland

20.1.7.17 Using Connector/ODBC with Borland Builder 4
.....................................................

When you start a query, you can use the `Active' property or the `Open'
method. Note that `Active' starts by automatically issuing a `SELECT *
FROM ...' query. That may not be a good thing if your tables are large.


File: manual.info,  Node: connector-odbc-usagenotes-apptips-borland-delphi,  Next: connector-odbc-usagenotes-apptips-borland-cppbuilder,  Prev: connector-odbc-usagenotes-apptips-borland-builder,  Up: connector-odbc-usagenotes-apptips-borland

20.1.7.18 Using Connector/ODBC with Delphi
..........................................

Also, here is some potentially useful Delphi code that sets up both an
ODBC entry and a BDE entry for Connector/ODBC.  The BDE entry requires
a BDE Alias Editor that is free at a Delphi Super Page near you.
(Thanks to Bryan Brunton <bryan@flesherfab.com> for this):

     fReg:= TRegistry.Create;
     fReg.OpenKey('\Software\ODBC\ODBC.INI\DocumentsFab', True);
     fReg.WriteString('Database', 'Documents');
     fReg.WriteString('Description', ' ');
     fReg.WriteString('Driver', 'C:\WINNT\System32\myodbc.dll');
     fReg.WriteString('Flag', '1');
     fReg.WriteString('Password', '');
     fReg.WriteString('Port', ' ');
     fReg.WriteString('Server', 'xmark');
     fReg.WriteString('User', 'winuser');
     fReg.OpenKey('\Software\ODBC\ODBC.INI\ODBC Data Sources', True);
     fReg.WriteString('DocumentsFab', 'MySQL');
     fReg.CloseKey;
     fReg.Free;

     Memo1.Lines.Add('DATABASE NAME=');
     Memo1.Lines.Add('USER NAME=');
     Memo1.Lines.Add('ODBC DSN=DocumentsFab');
     Memo1.Lines.Add('OPEN MODE=READ/WRITE');
     Memo1.Lines.Add('BATCH COUNT=200');
     Memo1.Lines.Add('LANGDRIVER=');
     Memo1.Lines.Add('MAX ROWS=-1');
     Memo1.Lines.Add('SCHEMA CACHE DIR=');
     Memo1.Lines.Add('SCHEMA CACHE SIZE=8');
     Memo1.Lines.Add('SCHEMA CACHE TIME=-1');
     Memo1.Lines.Add('SQLPASSTHRU MODE=SHARED AUTOCOMMIT');
     Memo1.Lines.Add('SQLQRYMODE=');
     Memo1.Lines.Add('ENABLE SCHEMA CACHE=FALSE');
     Memo1.Lines.Add('ENABLE BCD=FALSE');
     Memo1.Lines.Add('ROWSET SIZE=20');
     Memo1.Lines.Add('BLOBS TO CACHE=64');
     Memo1.Lines.Add('BLOB SIZE=32');

     AliasEditor.Add('DocumentsFab','MySQL',Memo1.Lines);


File: manual.info,  Node: connector-odbc-usagenotes-apptips-borland-cppbuilder,  Prev: connector-odbc-usagenotes-apptips-borland-delphi,  Up: connector-odbc-usagenotes-apptips-borland

20.1.7.19 Using Connector/ODBC with C++ Builder
...............................................

Tested with BDE 3.0. The only known problem is that when the table
schema changes, query fields are not updated. BDE, however, does not
seem to recognize primary keys, only the index named `PRIMARY',
although this has not been a problem.


File: manual.info,  Node: connector-odbc-usagenotes-apptips-coldfusion,  Next: connector-odbc-usagenotes-apptips-openoffice,  Prev: connector-odbc-usagenotes-apptips-borland,  Up: connector-odbc-usagenotes-apptips

20.1.7.20 Using Connector/ODBC with ColdFusion
..............................................

The following information is taken from the ColdFusion documentation:

Use the following information to configure ColdFusion Server for Linux
to use the `unixODBC' driver with Connector/ODBC for MySQL data
sources. You can download Connector/ODBC at
`http://dev.mysql.com/downloads/connector/odbc/'.

ColdFusion version 4.5.1 enables you to use the ColdFusion
Administrator to add the MySQL data source. However, the driver is not
included with ColdFusion version 4.5.1. Before the MySQL driver appears
in the ODBC data sources drop-down list, you must build and copy the
Connector/ODBC driver to `/opt/coldfusion/lib/libmyodbc.so'.

The Contrib directory contains the program `mydsn-XXX.zip' which
enables you to build and remove the DSN registry file for the
Connector/ODBC driver on ColdFusion applications.

For more information and guides on using ColdFusion and Connector/ODBC,
see the following external sites:

   * Troubleshooting Data Sources and Database Connectivity for Unix
     Platforms
     (http://www.macromedia.com/v1/handlers/index.cfm?ID=11328&Method=Full&PageCall=/support/index.cfm).


File: manual.info,  Node: connector-odbc-usagenotes-apptips-openoffice,  Next: connector-odbc-usagenotes-apptips-sambarserver,  Prev: connector-odbc-usagenotes-apptips-coldfusion,  Up: connector-odbc-usagenotes-apptips

20.1.7.21 Using Connector/ODBC with OpenOffice.org
..................................................

Open Office (`http://www.openoffice.org') How-to: MySQL + OpenOffice
(http://wiki.services.openoffice.org/wiki/Connect_MySQL_and_Base).
How-to: OpenOffice + MyODBC + unixODBC
(http://www.unixodbc.org/doc/OOoMySQL.pdf).


File: manual.info,  Node: connector-odbc-usagenotes-apptips-sambarserver,  Next: connector-odbc-usagenotes-apptips-datajunction,  Prev: connector-odbc-usagenotes-apptips-openoffice,  Up: connector-odbc-usagenotes-apptips

20.1.7.22 Using Connector/ODBC with Sambar Server
.................................................

Sambar Server (`http://www.sambarserver.info') How-to: MyODBC +
SambarServer + MySQL (http://www.sambarserver.info/article.php?sid=66).


File: manual.info,  Node: connector-odbc-usagenotes-apptips-datajunction,  Next: connector-odbc-usagenotes-apptips-vision,  Prev: connector-odbc-usagenotes-apptips-sambarserver,  Up: connector-odbc-usagenotes-apptips

20.1.7.23 Using Connector/ODBC with Pervasive Software DataJunction
...................................................................

You have to change it to output *Note `VARCHAR': char. rather than
*Note `ENUM': enum, as it exports the latter in a manner that causes
MySQL problems.


File: manual.info,  Node: connector-odbc-usagenotes-apptips-vision,  Prev: connector-odbc-usagenotes-apptips-datajunction,  Up: connector-odbc-usagenotes-apptips

20.1.7.24 Using Connector/ODBC with SunSystems Vision
.....................................................

You should select the `Return matching rows' option.


File: manual.info,  Node: connector-odbc-errors,  Prev: connector-odbc-usagenotes-apptips,  Up: connector-odbc-usagenotes

20.1.7.25 Connector/ODBC Errors and Resolutions (FAQ)
.....................................................

The following section details some common errors and their suggested
fix or alternative solution. If you are still experiencing problems,
use the Connector/ODBC mailing list; see *Note
connector-odbc-support-community::.

Many problems can be resolved by upgrading your Connector/ODBC drivers
to the latest available release. On Windows, you should also make sure
that you have the latest versions of the Microsoft Data Access
Components (MDAC) installed.

*Questions*
   * 20.1.7.3.1: I have installed Connector/ODBC on Windows XP x64
     Edition or Windows Server 2003 R2 x64. The installation completed
     successfully, but the Connector/ODBC driver does not appear in
     `ODBC Data Source Administrator'.

   * 20.1.7.3.2: When connecting or using the `Test' button in `ODBC
     Data Source Administrator' I get error 10061 (Cannot connect to
     server)

   * 20.1.7.3.3: The following error is reported when using
     transactions: `Transactions are not enabled'

   * 20.1.7.3.4: Access reports records as `#DELETED#' when inserting
     or updating records in linked tables.

   * 20.1.7.3.5: How do I handle Write Conflicts or Row Location errors?

   * 20.1.7.3.6: Exporting data from Access 97 to MySQL reports a
     `Syntax Error'.

   * 20.1.7.3.7: Exporting data from Microsoft DTS to MySQL reports a
     `Syntax Error'.

   * 20.1.7.3.8: Using ODBC.NET with Connector/ODBC, while fetching
     empty string (0 length), it starts giving the SQL_NO_DATA
     exception.

   * 20.1.7.3.9: Using `SELECT COUNT(*) FROM TBL_NAME' within Visual
     Basic and ASP returns an error.

   * 20.1.7.3.10: Using the `AppendChunk()' or `GetChunk()' ADO
     methods, the `Multiple-step operation generated errors. Check each
     status value' error is returned.

   * 20.1.7.3.11: Access Returns `Another user had modified the record
     that you have modified' while editing records on a Linked Table.

   * 20.1.7.3.12: When linking an application directly to the
     Connector/ODBC library under Unix/Linux, the application crashes.

   * 20.1.7.3.13: Applications in the Microsoft Office suite are unable
     to update tables that have *Note `DATE': datetime. or *Note
     `TIMESTAMP': datetime. columns.

   * 20.1.7.3.14: When connecting Connector/ODBC 5.x (Beta) to a MySQL
     4.x server, the error `1044 Access denied for user 'xxx'@'%' to
     database 'information_schema'' is returned.

   * 20.1.7.3.15: When calling `SQLTables', the error `S1T00' is
     returned, but I cannot find this in the list of error numbers for
     Connector/ODBC.

   * 20.1.7.3.16: When linking to tables in Access 2000 and generating
     links to tables programmatically, rather than through the table
     designer interface, you may get errors about tables not existing.

   * 20.1.7.3.17: When I try to use batched statements, the execution
     of the batched statements fails.

   * 20.1.7.3.18: When connecting to a MySQL server using ADODB and
     Excel, occasionally the application fails to communicate with the
     server and the error `Got an error reading communication packets'
     appears in the error log.

   * 20.1.7.3.19: When using some applications to access a MySQL server
     using C/ODBC and outer joins, an error is reported regarding the
     Outer Join Escape Sequence.

   * 20.1.7.3.20: I can correctly store extended characters in the
     database (Hebrew/CJK) using C/ODBC 5.1, but when I retrieve the
     data, the text is not formatted correctly and I get garbled
     characters.

   * 20.1.7.3.21: I have a duplicate MySQL Connector/ODBC entry within
     my `Installed Programs' list, but I cannot delete one of them.

   * 20.1.7.3.22: When submitting queries with parameter binding using
     *Note `UPDATE': update, my field values are being truncated to 255
     characters.

   * 20.1.7.3.23: Is it possible to disable data-at-execution using a
     flag?

   * 20.1.7.3.24: When you call `SQLColumns()' for a table column that
     is `AUTO_INCREMENT', the `NULLABLE' column of the result set is
     always `SQL_NULLABLE (1)'.

*Questions and Answers* *20.1.7.3.1: ** I have installed Connector/ODBC
on Windows XP x64 Edition or Windows Server 2003 R2 x64. The
installation completed successfully, but the Connector/ODBC driver does
not appear in `ODBC Data Source Administrator'.  *

This is not a bug, but is related to the way Windows x64 editions
operate with the ODBC driver. On Windows x64 editions, the
Connector/ODBC driver is installed in the `%SystemRoot%\SysWOW64'
folder.  However, the default `ODBC Data Source Administrator' that is
available through the `Administrative Tools' or `Control Panel' in
Windows x64 Editions is located in the `%SystemRoot%\system32' folder,
and only searches this folder for ODBC drivers.

On Windows x64 editions, you should use the ODBC administration tool
located at `%SystemRoot%\SysWOW64\odbcad32.exe', this will correctly
locate the installed Connector/ODBC drivers and enable you to create a
Connector/ODBC DSN.

This issue was originally reported as Bug #20301.

*20.1.7.3.2: ** When connecting or using the `Test' button in `ODBC
Data Source Administrator' I get error 10061 (Cannot connect to server)
*

This error can be raised by a number of different issues, including
server problems, network problems, and firewall and port blocking
problems. For more information, see *Note can-not-connect-to-server::.

*20.1.7.3.3: ** The following error is reported when using transactions:
`Transactions are not enabled' *

This error indicates that you are trying to use transactions with a
MySQL table that does not support transactions. Transactions are
supported within MySQL when using the `InnoDB' database engine. In
versions of MySQL before Mysql 5.1 you may also use the `BDB' engine.

You should check the following before continuing:

   * Verify that your MySQL server supports a transactional database
     engine. Use *Note `SHOW ENGINES': show-engines. to obtain a list
     of the available engine types.

   * Verify that the tables you are updating use a transaction database
     engine.

   * Ensure that you have not enabled the `disable transactions' option
     in your DSN.

*20.1.7.3.4: ** Access reports records as `#DELETED#' when inserting or
updating records in linked tables.  *

If the inserted or updated records are shown as `#DELETED#' in the
access, then:

   * If you are using Access 2000, you should get and install the
     newest (version 2.6 or higher) Microsoft MDAC (`Microsoft Data
     Access Components') from `http://support.microsoft.com/kb/110093'.
     This fixes a bug in Access that when you export data to MySQL, the
     table and column names aren't specified.

     You should also get and apply the Microsoft Jet 4.0 Service Pack 5
     (SP5) which can be found at
     `http://support.microsoft.com/default.aspx?scid=kb;EN-US;q239114'.
     This fixes some cases where columns are marked as `#DELETED#' in
     Access.

   * For all versions of Access, you should enable the Connector/ODBC
     `Return matching rows' option. For Access 2.0, you should
     additionally enable the `Simulate ODBC 1.0' option.

   * You should have a timestamp in all tables that you want to be able
     to update.

   * You should have a primary key in the table. If not, new or updated
     rows may show up as `#DELETED#'.

   * Use only *Note `DOUBLE': numeric-types. float fields. Access fails
     when comparing with single-precision floats. The symptom usually
     is that new or updated rows may show up as `#DELETED#' or that you
     cannot find or update rows.

   * If you are using Connector/ODBC to link to a table that has a
     *Note `BIGINT': numeric-types.  column, the results are displayed
     as `#DELETED'. The work around solution is:

        * Have one more dummy column with *Note `TIMESTAMP': datetime.
          as the data type.

        * Select the `Change BIGINT columns to INT' option in the
          connection dialog in ODBC DSN Administrator.

        * Delete the table link from Access and re-create it.

     Old records still display as `#DELETED#', but newly added/updated
     records are displayed properly.

*20.1.7.3.5: ** How do I handle Write Conflicts or Row Location errors?
*

If you see the following errors, select the `Return Matching Rows'
option in the DSN configuration dialog, or specify `OPTION=2', as the
connection parameter:

     Write Conflict. Another user has changed your data.

     Row cannot be located for updating. Some values may have been changed
     since it was last read.

*20.1.7.3.6: ** Exporting data from Access 97 to MySQL reports a
`Syntax Error'.  *

This error is specific to Access 97 and versions of Connector/ODBC
earlier than 3.51.02. Update to the latest version of the
Connector/ODBC driver to resolve this problem.

*20.1.7.3.7: ** Exporting data from Microsoft DTS to MySQL reports a
`Syntax Error'.  *

This error occurs only with MySQL tables using the *Note `TEXT': blob.
or *Note `VARCHAR': char. data types. You can fix this error by
upgrading your Connector/ODBC driver to version 3.51.02 or higher.

*20.1.7.3.8: ** Using ODBC.NET with Connector/ODBC, while fetching empty
string (0 length), it starts giving the SQL_NO_DATA exception.  *

You can get the patch that addresses this problem from
`http://support.microsoft.com/default.aspx?scid=kb;EN-US;q319243'.

*20.1.7.3.9: ** Using `SELECT COUNT(*) FROM TBL_NAME' within Visual
Basic and ASP returns an error.  *

This error occurs because the `COUNT(*)' expression is returning a
*Note `BIGINT': numeric-types, and ADO cannot make sense of a number
this big. Select the `Change BIGINT columns to INT' option (option
value 16384).

*20.1.7.3.10: ** Using the `AppendChunk()' or `GetChunk()' ADO methods,
the `Multiple-step operation generated errors. Check each status value'
error is returned.  *

The `GetChunk()' and `AppendChunk()' methods from ADO doesn't work as
expected when the cursor location is specified as `adUseServer'. On the
other hand, you can overcome this error by using `adUseClient'.

A simple example can be found from
`http://www.dwam.net/iishelp/ado/docs/adomth02_4.htm'

*20.1.7.3.11: ** Access Returns `Another user had modified the record
that you have modified' while editing records on a Linked Table.  *

In most cases, this can be solved by doing one of the following things:

   * Add a primary key for the table if one doesn't exist.

   * Add a timestamp column if one doesn't exist.

   * Only use double-precision float fields. Some programs may fail
     when they compare single-precision floats.

If these strategies do not help, you should start by making a log file
from the ODBC manager (the log you get when requesting logs from
ODBCADMIN) and a Connector/ODBC log to help you figure out why things
go wrong. For instructions, see *Note
connector-odbc-configuration-trace::.

*20.1.7.3.12: ** When linking an application directly to the
Connector/ODBC library under Unix/Linux, the application crashes.  *

Connector/ODBC 3.51 under Unix/Linux is not compatible with direct
application linking. You must use a driver manager, such as iODBC or
unixODBC to connect to an ODBC source.

*20.1.7.3.13: ** Applications in the Microsoft Office suite are unable
to update tables that have *Note `DATE': datetime. or *Note
`TIMESTAMP': datetime. columns.  *

This is a known issue with Connector/ODBC. You must ensure that the
field has a default value (rather than `NULL' and that the default
value is nonzero (that is, the default value is not `0000-00-00
00:00:00').

*20.1.7.3.14: ** When connecting Connector/ODBC 5.x (Beta) to a MySQL
4.x server, the error `1044 Access denied for user 'xxx'@'%' to
database 'information_schema'' is returned.  *

Connector/ODBC 5.x is designed to work with MySQL 5.0 or later, taking
advantage of the `INFORMATION_SCHEMA' database to determine data
definition information. Support for MySQL 4.1 is planned for the final
release.

*20.1.7.3.15: ** When calling `SQLTables', the error `S1T00' is
returned, but I cannot find this in the list of error numbers for
Connector/ODBC.  *

The `S1T00' error indicates that a general timeout has occurred within
the ODBC system and is not a MySQL error. Typically it indicates that
the connection you are using is stale, the server is too busy to accept
your request or that the server has gone away.

*20.1.7.3.16: ** When linking to tables in Access 2000 and generating
links to tables programmatically, rather than through the table
designer interface, you may get errors about tables not existing.  *

There is a known issue with a specific version of the `msjet40.dll'
that exhibits this issue.  The version affected is 4.0.9025.0.
Reverting to an older version will enable you to create the links. If
you have recently updated your version, check your `WINDOWS' directory
for the older version of the file and copy it to the drivers directory.

*20.1.7.3.17: ** When I try to use batched statements, the execution of
the batched statements fails.  *

Batched statement support was added in 3.51.18. Support for batched
statements is not enabled by default. You must enable option
`FLAG_MULTI_STATEMENTS', value 67108864, or select the `Allow multiple
statements' flag within a GUI configuration.

*20.1.7.3.18: ** When connecting to a MySQL server using ADODB and
Excel, occasionally the application fails to communicate with the
server and the error `Got an error reading communication packets'
appears in the error log.  *

This error may be related to Keyboard Logger 1.1 from PanteraSoft.com,
which is known to interfere with the network communication between
MySQL Connector/ODBC and MySQL.

*20.1.7.3.19: ** When using some applications to access a MySQL server
using C/ODBC and outer joins, an error is reported regarding the Outer
Join Escape Sequence.  *

This is a known issue with MySQL Connector/ODBC which is not correctly
parsing the "Outer Join Escape Sequence", as per the specs at Microsoft
ODBC Specs (http://msdn2.microsoft.com/en-us/library/ms710299.aspx).
Currently, Connector/ODBC will return value > 0 when asked for
`SQL_OJ_CAPABILITIES' even though no parsing takes place in the driver
to handle the outer join escape sequence.

*20.1.7.3.20: ** I can correctly store extended characters in the
database (Hebrew/CJK) using C/ODBC 5.1, but when I retrieve the data,
the text is not formatted correctly and I get garbled characters.  *

When using ASP and UTF8 characters you should add the following to your
ASP files to ensure that the data returned is correctly encoded:

     Response.CodePage = 65001
     Response.CharSet = "utf-8"

*20.1.7.3.21: ** I have a duplicate MySQL Connector/ODBC entry within my
`Installed Programs' list, but I cannot delete one of them.  *

This problem can occur when you upgrade an existing Connector/ODBC
installation, rather than removing and then installing the updated
version.

*Warning*:

To fix the problem you should use any working uninstallers to remove
existing installations and then may have to edit the contents of the
registry. Make sure you have a backup of your registry information
before attempting any editing of the registry contents.

*20.1.7.3.22: ** When submitting queries with parameter binding using
*Note `UPDATE': update, my field values are being truncated to 255
characters.  *

You should ensure that the `FLAG_BIG_PACKETS' option is set for your
connection. This removes the 255 character limitation on bound
parameters.

*20.1.7.3.23: ** Is it possible to disable data-at-execution using a
flag?  *

If you do not want to use data-at-execution, simply remove the
corresponding calls. For example:

     SQLLEN ylen = SQL_LEN_DATA_AT_EXEC(10);
     SQLBindCol(hstmt,2,SQL_C_BINARY, buf, 10, &ylen);

Would become:

     SQLBindCol(hstmt,2,SQL_C_BINARY, buf, 10, NULL);

Note that in the call to `SQLBindCol()', &ylen has been replaced by
NULL.

For further information please refer to the MSDN documentation
(http://msdn.microsoft.com/en-us/library/ms711010(VS.85).aspx) for
`SQLBindCol()'.

*20.1.7.3.24: ** When you call `SQLColumns()' for a table column that
is `AUTO_INCREMENT', the `NULLABLE' column of the result set is always
`SQL_NULLABLE (1)'.  *

This is because MySQL reports the `DEFAULT' value for such a column as
`NULL'. It means, if you insert a `NULL' value into the column, you will
get the next integer value for the table's `auto_increment' counter.


File: manual.info,  Node: connector-odbc-support,  Prev: connector-odbc-usagenotes,  Up: connector-odbc

20.1.8 Connector/ODBC Support
-----------------------------

* Menu:

* connector-odbc-support-community::  Connector/ODBC Community Support
* connector-odbc-support-bug-report::  How to Report Connector/ODBC Problems or Bugs
* connector-odbc-support-patch-submission::  How to Submit a Connector/ODBC Patch
* connector-odbc-support-changehistory::  Connector/ODBC Change History
* connector-odbc-support-credits::  Credits

There are many different places where you can get support for using
Connector/ODBC. You should always try the Connector/ODBC Mailing List
or Connector/ODBC Forum. See *Note connector-odbc-support-community::,
for help before reporting a specific bug or issue to MySQL.


File: manual.info,  Node: connector-odbc-support-community,  Next: connector-odbc-support-bug-report,  Prev: connector-odbc-support,  Up: connector-odbc-support

20.1.8.1 Connector/ODBC Community Support
.........................................

Oracle provides assistance to the user community by means of its
mailing lists. For Connector/ODBC-related issues, you can get help from
experienced users by using the <myodbc@lists.mysql.com> mailing list.
Archives are available online at `http://lists.mysql.com/myodbc'.

For information about subscribing to MySQL mailing lists or to browse
list archives, visit `http://lists.mysql.com/'. See *Note
mailing-lists::.

Community support from experienced users is also available through the
ODBC Forum (http://forums.mysql.com/list.php?37). You may also find
help from other users in the other MySQL Forums, located at
`http://forums.mysql.com'. See *Note forums::.


File: manual.info,  Node: connector-odbc-support-bug-report,  Next: connector-odbc-support-patch-submission,  Prev: connector-odbc-support-community,  Up: connector-odbc-support

20.1.8.2 How to Report Connector/ODBC Problems or Bugs
......................................................

If you encounter difficulties or problems with Connector/ODBC, you
should start by making a log file from the `ODBC Manager' (the log you
get when requesting logs from `ODBC ADMIN') and Connector/ODBC. The
procedure for doing this is described in *Note
connector-odbc-configuration-trace::.

Check the Connector/ODBC trace file to find out what could be wrong.
You should be able to determine what statements were issued by
searching for the string `>mysql_real_query' in the `myodbc.log' file.

You should also try issuing the statements from the *Note `mysql':
mysql. client program or from `admndemo'. This helps you determine
whether the error is in Connector/ODBC or MySQL.

If you find out something is wrong, please only send the relevant rows
(maximum 40 rows) to the `myodbc' mailing list. See *Note
mailing-lists::. Please never send the whole Connector/ODBC or ODBC log
file!

You should ideally include the following information with the email:

   * Operating system and version

   * Connector/ODBC version

   * ODBC Driver Manager type and version

   * MySQL server version

   * ODBC trace from Driver Manager

   * Connector/ODBC log file from Connector/ODBC driver

   * Simple reproducible sample

Remember that the more information you can supply to us, the more
likely it is that we can fix the problem!

Also, before posting the bug, check the MyODBC mailing list archive at
`http://lists.mysql.com/myodbc'.

If you are unable to find out what is wrong, the last option is to
create an archive in `tar' or Zip format that contains a Connector/ODBC
trace file, the ODBC log file, and a `README' file that explains the
problem. You can send this to `ftp://ftp.mysql.com/pub/mysql/upload/'.
Only MySQL engineers have access to the files you upload, and we are
very discreet with the data.

If you can create a program that also demonstrates the problem, please
include it in the archive as well.

If the program works with another SQL server, you should include an
ODBC log file where you perform exactly the same SQL statements so that
we can compare the results between the two systems.

Remember that the more information you can supply to us, the more
likely it is that we can fix the problem.


File: manual.info,  Node: connector-odbc-support-patch-submission,  Next: connector-odbc-support-changehistory,  Prev: connector-odbc-support-bug-report,  Up: connector-odbc-support

20.1.8.3 How to Submit a Connector/ODBC Patch
.............................................

You can send a patch or suggest a better solution for any existing code
or problems by sending a mail message to <myodbc@lists.mysql.com>.


File: manual.info,  Node: connector-odbc-support-changehistory,  Next: connector-odbc-support-credits,  Prev: connector-odbc-support-patch-submission,  Up: connector-odbc-support

20.1.8.4 Connector/ODBC Change History
......................................

The Connector/ODBC Change History (Changelog) is located with the main
Changelog for MySQL. See *Note connector-odbc-news::.


File: manual.info,  Node: connector-odbc-support-credits,  Prev: connector-odbc-support-changehistory,  Up: connector-odbc-support

20.1.8.5 Credits
................

These are the developers that have worked on the Connector/ODBC and
Connector/ODBC 3.51 Drivers from MySQL AB.

   * Michael (Monty) Widenius

   * Venu Anuganti

   * Peter Harvey


File: manual.info,  Node: connector-net,  Next: connector-j,  Prev: connector-odbc,  Up: connectors-apis

20.2 MySQL Connector/Net
========================

* Menu:

* connector-net-versions::       Connector/Net Versions
* connector-net-installation::   Connector/Net Installation
* connector-net-visual-studio::  Connector/Net Visual Studio Integration
* connector-net-tutorials::      Connector/Net Tutorials
* connector-net-programming::    Connector/Net Programming
* connector-net-connection-options::  Connector/Net Connection String Options Reference
* connector-net-ref::            Connector/Net API Reference
* connector-net-support::        Connector/Net Support
* connector-net-faq::            Connector/Net FAQ

Connector/Net enables developers to easily create .NET applications
that require secure, high-performance data connectivity with MySQL.  It
implements the required ADO.NET interfaces and integrates into ADO.NET
aware tools. Developers can build applications using their choice of
.NET languages. Connector/Net is a fully managed ADO.NET driver written
in 100% pure C#.

Connector/Net includes full support for:

   * Features provided by MySQL Server up to and including MySQL Server
     version 5.5.

   * Large-packet support for sending and receiving rows and BLOBs up
     to 2 gigabytes in size.

   * Protocol compression which enables compressing the data stream
     between the client and server.

   * Support for connecting using TCP/IP sockets, named pipes, or
     shared memory on Windows.

   * Support for connecting using TCP/IP sockets or Unix sockets on
     Unix.

   * Support for the Open Source Mono framework developed by Novell.

   * Fully managed, does not utilize the MySQL client library.

This document is intended as a user's guide to Connector/Net and
includes a full syntax reference. Syntax information is also included
within the `Documentation.chm' file included with the Connector/Net
distribution.

If you are using MySQL 5.0 or later, and Visual Studio as your
development environment, you may want also want to use the MySQL Visual
Studio Plugin. The plugin acts as a DDEX (Data Designer Extensibility)
provider, enabling you to use the data design tools within Visual
Studio to manipulate the schema and objects within a MySQL database.
For more information, see *Note connector-net-visual-studio::.

*Note*:

Connector/Net 5.1.2 and later include the Visual Studio Plugin by
default.

MySQL Connector/Net supports full versions of Visual Studio 2005, 2008,
and 2010, although certain features are only available in Visual Studio
2010 when using MySQL Connector/Net version 6.3.2 and later. Note that
MySQL Connector/Net does not currently support Express versions of
Microsoft products, including Microsoft Visual Web Developer.

*Key topics:*

   * For connection string properties when using the MySqlConnection
     class, see *Note connector-net-connection-options::.


File: manual.info,  Node: connector-net-versions,  Next: connector-net-installation,  Prev: connector-net,  Up: connector-net

20.2.1 Connector/Net Versions
-----------------------------

There are several versions of Connector/Net available:

   * Connector/Net 1.0 includes support for MySQL Server 4.0, 4.1, and
     5.0 features, and full compatibility with the ADO.NET driver
     interface.

     This version of Connector/Net is no longer supported.

   * Connector/Net 5.0 includes support for MySQL Server 4.0, 4.1, 5.0
     and 5.1 features. Connector/Net 5.0 also includes full support for
     the ADO.Net 2.0 interfaces and subclasses, includes support for
     the usage advisor and performance monitor (PerfMon) hooks.

     This version of Connector/Net is no longer supported.

   * Connector/Net 5.1 includes support for MySQL Server 4.0, 4.1, 5.0,
     5.1, 5.4 and 5.5 features. Connector/Net 5.1 also includes support
     for a new membership/role provider, Compact Framework 2.0, a new
     stored procedure parser and improvements to `GetSchema'.
     Connector/Net 5.1 also includes the Visual Studio Plugin as a
     standard installable component.

     This version of Connector/Net is no longer supported.

   * Connector/Net 5.2 includes support for MySQL Server 4.1, 5.0, 5.1,
     5.4, and 5.5 features. Connector/Net 5.2 also includes support for
     a new membership/role provider, Compact Framework 2.0, a new
     stored procedure parser and improvements to `GetSchema'.
     Connector/Net 5.2 also includes the Visual Studio Plugin as a
     standard installable component.

     This version of Connector/Net is no longer supported.

   * Connector/Net 6.0 includes support for MySQL Server 4.1, 5.0, 5.1,
     5.4 and 5.5.

     This version of Connector/Net is no longer supported.

   * Connector/Net 6.1 includes support for MySQL Server 4.1, 5.0, 5.1,
     5.4, and 5.5. Important new features include the MySQL Website
     Configuration Tool and a Session State Provider.

   * Connector/Net 6.2 includes support for MySQL Server 4.1, 5.0, 5.1,
     5.4, and 5.5. Important new features include a new logging system
     and client SSL certificates. Connector/Net 6.2 is currently
     available as a Beta release.

   * Connector/Net 6.3 includes support for MySQL Server 5.0, 5.1, 5.4,
     and 5.5. Important new features include integration with Visual
     Studio 2010, such as availability of DDL T4 template for Entity
     Framework, and a custom MySQL SQL Editor. Other features include
     refactored transaction scope: Connector/Net now supports nested
     transactions in a scope where they use the same connection string.
     Connector/Net 6.3 is available as a Beta release.

The latest source code for Connector/Net can be downloaded from the
MySQL public Subversion server. For further details see *Note
connector-net-installation-source::.

The following table shows the .NET Framework version required, and
MySQL Server version supported by Connector/Net:

Connector/Net      ADO.NET version    .NET Framework     MySQL Server       Currently
version            supported          version required   version supported  supported
1.0                1.x                1.x                4.0, 4.1, 5.0      No
5.0                2.x+               2.x+               4.0, 4.1, 5.0      No
5.1                2.x+               2.x+               4.0, 4.1, 5.0,     No
                                                         5.1, 5.4, 5.5      
5.2                2.x+               2.x+               4.1, 5.0, 5.1,     No
                                                         5.4, 5.5           
6.0                2.x+               2.x+               4.1, 5.0, 5.1,     Critical issues
                                                         5.4, 5.5           only
6.1                2.x+               2.x+               4.1, 5.0, 5.1,     Yes
                                                         5.4, 5.5           
6.2                2.x+               2.x+               4.1, 5.0, 5.1,     Yes
                                                         5.4, 5.5           
6.3                2.x+               2.x+, 4.x+ for VS  5.0, 5.1, 5.4, 5.5 Yes
                                      2010 support                          

*Note*:

Version numbers for MySQL products are formatted as X.Y.Z, where Z=0
indicates alpha, Z=1 indicates beta, and Z>=2 indicates GA.  However,
Windows tools (Control Panel, properties display) may show the version
numbers as XX.YY.ZZ. For example, the official MySQL formatted version
number 5.0.9 may be displayed by Windows tools as 5.00.09. The two
versions are the same; only the number display format is different.


File: manual.info,  Node: connector-net-installation,  Next: connector-net-visual-studio,  Prev: connector-net-versions,  Up: connector-net

20.2.2 Connector/Net Installation
---------------------------------

* Menu:

* connector-net-installation-windows::  Installing Connector/Net on Windows
* connector-net-installation-unix::  Installing Connector/Net on Unix with Mono
* connector-net-installation-source::  Installing Connector/Net from the source code

Connector/Net runs on any platform that supports the .NET framework.
The .NET framework is primarily supported on recent versions of
Microsoft Windows, and is supported on Linux through the Open Source
Mono framework (see `http://www.mono-project.com').

Connector/Net is available for download from
`http://dev.mysql.com/downloads/connector/net/5.2.html'.


File: manual.info,  Node: connector-net-installation-windows,  Next: connector-net-installation-unix,  Prev: connector-net-installation,  Up: connector-net-installation

20.2.2.1 Installing Connector/Net on Windows
............................................

* Menu:

* connector-net-installation-binary-windows-installer::  Installing Connector/Net using the Installer
* connector-net-installation-binary-windows-zip::  Installing Connector/Net using the Zip packages

On Windows, installation is supported either through a binary
installation process or by downloading a Zip file with the
Connector/Net components.

Before installing, you should ensure that your system is up to date,
including installing the latest version of the .NET Framework.


File: manual.info,  Node: connector-net-installation-binary-windows-installer,  Next: connector-net-installation-binary-windows-zip,  Prev: connector-net-installation-windows,  Up: connector-net-installation-windows

20.2.2.2 Installing Connector/Net using the Installer
.....................................................

Using the installer is the most straightforward method of installing
Connector/Net on Windows and the installed components include the
source code, test code and full reference documentation.

Connector/Net is installed through the use of a Windows Installer
(`.msi') installation package, which can be used to install
Connector/Net on all Windows operating systems. The MSI package in
contained within a Zip archive named `mysql-connector-net-VERSION.zip',
where VERSION indicates the Connector/Net version.

To install Connector/Net:

  1. Double-click the MSI installer file extracted from the Zip you
     downloaded. Click `Next' to start the installation.

     Connector/Net Windows Installer - Welcome

  2. You must choose the type of installation to perform.

     Connector/Net Windows Installer - Installation type

     For most situations, the Typical installation is suitable.  Click
     the `Typical' button and proceed to Step 5. A Complete
     installation installs all the available files. To conduct a
     Complete installation, click the `Complete' button and proceed to
     step 5. To customize your installation, including choosing the
     components to install and some installation options, click the
     `Custom' button and proceed to Step 3.

     The Connector/Net installer will register the connector within the
     Global Assembly Cache (GAC) - this will make the Connector/Net
     component available to all applications, not just those where you
     explicitly reference the Connector/Net component. The installer
     will also create the necessary links in the Start menu to the
     documentation and release notes.

  3. If you have chosen a custom installation, you can select the
     individual components to install, including the core interface
     component, supporting documentation (a CHM file) samples and
     examples, and the source code. Select the items, and their
     installation level, and then click `Next' to continue the
     installation.

     *Note*:

     For Connector/Net 1.0.8 or lower and Connector 5.0.4 and lower the
     installer will attempt to install binaries for both 1.x and 2.x of
     the .NET Framework. If you only have one version of the framework
     installed, the connector installation may fail. If this happens,
     you can choose the framework version to be installed through the
     custom installation step.

     Connector/Net Windows Installer - Custom setup

  4. You will be given a final opportunity to confirm the installation.
     Click `Install' to copy and install the files onto your machine.

     Connector/Net Windows Installer - Confirming installation

  5. Once the installation has been completed, click `Finish' to exit
     the installer.

     Connector/Net Windows Installer - Finish installation

Unless you choose otherwise, Connector/Net is installed in `C:\Program
Files\MySQL\MySQL Connector Net X.X.X', where X.X.X is replaced with
the version of Connector/Net you are installing. New installations do
not overwrite existing versions of Connector/Net.

Depending on your installation type, the installed components will
include some or all of the following components:

   * `bin': Connector/Net MySQL libraries for different versions of the
     .NET environment.

   * `docs': Connector/Net documentation in CHM format.

   * `samples': Sample code and applications that use the Connector/Net
     component.

   * `src': The source code for the Connector/Net component.

You may also use the `/quiet' or `/q' command-line option with the
`msiexec' tool to install the Connector/Net package automatically
(using the default options) with no notification to the user. Using
this method the user cannot select options. Additionally, no prompts,
messages or dialog boxes will be displayed.

     C:\> msiexec /package connector-net.msi /quiet

To provide a progress bar to the user during automatic installation,
use the `/passive' option.


File: manual.info,  Node: connector-net-installation-binary-windows-zip,  Prev: connector-net-installation-binary-windows-installer,  Up: connector-net-installation-windows

20.2.2.3 Installing Connector/Net using the Zip packages
........................................................

If you are having problems running the installer, you can download a
Zip file without an installer as an alternative. That file is called
`mysql-connector-net-VERSION-noinstall.zip'.  Once downloaded, you can
extract the files to a location of your choice.

The file contains the following directories:

   * `bin': Connector/Net MySQL libraries for different versions of the
     .NET environment.

   * `Docs': Connector/Net documentation in CHM format.

   * `Samples': Sample code and applications that use the Connector/Net
     component.

Connector/Net 6.0.x has a different directory structure:

   * `Assemblies': A collection of DLLs that make up the connector
     functionality.

   * `Documentation': Connector/Net documentation in CHM format.

   * `Samples': sample code and applications that use the Connector/Net
     component.

There is also another Zip file available for download called
`mysql-connector-net-VERSION-src.zip'.  This file contains the source
code distribution.

The file contains the following directories:

   * `Documentation': Source files to build the documentation into the
     compiled HTML (CHM) format.

   * `Installer': Source files to build the Connector/Net installer
     program.

   * `MySql.Data': Source files for the core data provider.

   * `MySql.VisualStudio': Source files for the Microsoft Visual Studio
     extensions.

   * `MySql.Web': Source files for the web providers. This includes
     code for the membership provider, role provider and profile
     provider. These are used in ASP.NET web sites.

   * `Samples': Source files for several example applications.

   * `Tests': A spreadsheet listing test cases.

   * `VisualStudio': Resources used by the Visual Studio plugin.

Finally, ensure that `MySql.Data.dll' is accessible to your program at
build time (and run time). If using Microsoft Visual Studio, add
`MySql.Data' as a Reference to your project.

*Note*:

If using MySQL Connector/Net 6.3.5 and above, the `MySql.Data' file
provided will work with both .NET Framework 2.x and 4.x.


File: manual.info,  Node: connector-net-installation-unix,  Next: connector-net-installation-source,  Prev: connector-net-installation-windows,  Up: connector-net-installation

20.2.2.4 Installing Connector/Net on Unix with Mono
...................................................

There is no installer available for installing the Connector/Net
component on your Unix installation. Before installing, please ensure
that you have a working Mono project installation. You can test whether
your system has Mono installed by typing:

     shell> mono --version

The version of the Mono JIT compiler is displayed.

To compile C# source code, make sure a Mono C# compiler is installed.
Note that there are two Mono C# compilers available, `mcs', which
accesses the 1.0-profile libraries, and `gmcs', which accesses the
2.0-profile libraries.

To install Connector/Net on Unix/Mono:

  1. Download the `mysql-connector-net-VERSION-noinstall.zip' and
     extract the contents to a directory of your choice, for example:
     `~/connector-net/'.

  2. In the directory where you unzipped the connector to, change into
     the `bin' directory. Ensure the file `MySql.Data.dll' is present.

  3. You must register the Connector/Net component, `MySql.Data', in
     the Global Assembly Cache (GAC). In the current directory enter the
     `gacutil' command:

          root-shell> gacutil /i MySql.Data.dll

     This will register `MySql.Data' into the GAC.  You can check this
     by listing the contents of `/usr/lib/mono/gac', where you will find
     `MySql.Data' if the registration has been successful.

You are now ready to compile your application. You must ensure that
when you compile your application you include the Connector/Net
component using the `-r:' command-line option. For example:

     shell> gmcs -r:System.dll -r:System.Data.dll -r:MySql.Data.dll HelloWorld.cs

Note, the assemblies that are referenced depend on the requirements of
the application, but applications using Connector/Net must provide
`-r:MySql.Data' as a minimum.

You can further check your installation by running the compiled
program, for example:

     shell> mono HelloWorld.exe


File: manual.info,  Node: connector-net-installation-source,  Prev: connector-net-installation-unix,  Up: connector-net-installation

20.2.2.5 Installing Connector/Net from the source code
......................................................

*Caution*:

Read this section only if you are interested in helping us test our new
code. If you just want to get Connector/Net up and running on your
system, use a standard release distribution.

*Obtaining the source code*

To obtain the most recent development source tree, you first need to
download and install Bazaar. You can obtain Bazaar from the Bazaar VCS
Website (http://bazaar-vcs.org).  Bazaar is supported by any platform
that supports Python, and is therefore compatible with any Linux, Unix,
Windows or Mac OS X host. Instructions for downloading and installing
Bazaar on the different platforms are available on the Bazaar Web site.

The most recent development source tree is available from our public
Subversion trees at `http://dev.mysql.com/tech-resources/sources.html'.

To check out out the Connector/Net sources, change to the directory
where you want the copy of the Connector/Net tree to be stored, then
use the following command:

     shell> bzr branch lp:connectornet/trunk

To download a specific version of Connector/Net, specify the version
number instead of `trunk'. For example, to obtain a copy of the 6.0
version of the source tree:

     shell> bzr branch lp:connectornet/6.0

Source packages are also available on the downloads page.

*Building the source code on Windows*

The following procedure can be used to build the connector on Microsoft
Windows.

   * Obtain the source code, either from the Subversion server, or
     through one of the prepared source code packages.

   * Navigate to the root of the source code tree.

   * A Microsoft Visual Studio 2005 solution file is available to build
     the connector, this is called `MySQL-VS2005.sln'. Click this file
     to load the solution into Visual Studio.

   * Select `Build', `Build Solution' from the main menu to build the
     solution.

*Building the source code on Unix*

Support for building Connector/Net on Mono/Unix is currently not
available.


File: manual.info,  Node: connector-net-visual-studio,  Next: connector-net-tutorials,  Prev: connector-net-installation,  Up: connector-net

20.2.3 Connector/Net Visual Studio Integration
----------------------------------------------

* Menu:

* connector-net-visual-studio-making-a-connection::  Making a connection
* connector-net-visual-studio-editing-tables::  Editing Tables
* connector-net-visual-studio-editing-views::  Editing Views
* connector-net-visual-studio-editing-stored-procedures-and-functions::  Editing Stored Procedures and Functions
* connector-net-visual-studio-editing-triggers::  Editing Triggers
* connector-net-visual-studio-editing-user-defined-functions-udf::  Editing User Defined Functions (UDF)
* connector-net-visual-studio-cloning-database-objects::  Cloning Database Objects
* connector-net-visual-studio-dropping-database-objects::  Dropping Database Objects
* connector-net-visual-studio-entity-framework::  Using the ADO.NET Entity Framework
* connector-net-website-config::  MySQL Website Configuration Tool
* connector-net-sql-editor::     MySQL SQL Editor
* connector-net-ddl-t4-ef::      DDL T4 Template Macro

When MySQL Connector/Net is installed on Microsoft Windows, Visual
Studio integration components are also installed and initialized. This
enables the developer to work seamlessly with MySQL Connector/Net in
the familiar Visual Studio environment, as described in the following
sections of the manual.

MySQL Connector/Net supports Visual Studio versions 2005, 2008, and
2010.  However, only MySQL Connector/Net version 6.3 fully integrates
with Visual Studio 2010, although applications using earlier versions
of the connector can be built with the Visual Studio 2010 environment
using .NET 2.x frameworks.

Visual Studio 2010 support was introduced with MySQL Connector/Net
6.3.2. From version 6.3.2 the connector ships with both .NET 2.x and
.NET 4.x versions of the entity framework support files,
`mysql.data.ef.dll' and ` mysql.visualstudio.dll'. The .NET 4.x
versions need to be shipped to enable new integration features
supported in Visual Studio 2010, including:

   * New DDL T4 template for the Entity Framework (EF) - This enables
     developers to design an EF model from scratch and use the native
     Visual Studio 2010 facility to generate MySQL DDL from that model.
     This is done by creating the model, and with the model open,
     choosing the SSDLToMySQL template in the properties window. The
     correct DDL is then generated. The developer can then save this
     code as a `.mysql' file in their project and execute it against
     the MySQL server.

   * New SQL Editor - A new SQL editor has been included that enables
     connections to servers to execute SQL. This is activated by
     creating a new file with a `.mysql' extension. A new template is
     also included to allow creation of this file type using the Visual
     Studio 2010 main menu item `File', `New'. Note that the MySQL SQL
     Editor is also available in 2005 and 2008.


File: manual.info,  Node: connector-net-visual-studio-making-a-connection,  Next: connector-net-visual-studio-editing-tables,  Prev: connector-net-visual-studio,  Up: connector-net-visual-studio

20.2.3.1 Making a connection
............................

Once the connector is installed, you can use it to create, modify, and
delete connections to MySQL databases. To create a connection with a
MySQL database, perform the following steps:

   * Start Visual Studio, and open the Server Explorer window (`View',
     `Server Explorer' option in the main Visual Studio menu, or
     `Control+W', `L' keyboard shortcuts).

   * Right-click the Data Connections node, and choose the `Add
     Connection...' menu item.

   * Add Connection dialog opens. Press the `Change' button to choose
     MySQL Database as a data source.

     FIGURE GOES HERE: Add Connection Context Menu

   * Change Data Source dialog opens. Choose MySQL Database in the list
     of data sources (or the `<other>' option, if MySQL Database is
     absent), and then choose .NET Framework Data Provider for MySQL in
     the combo box of data providers.

     FIGURE GOES HERE: Choose Data Source

   * Input the connection settings: the server host name (for example,
     localhost if the MySQL server is installed on the local machine),
     the user name, the password, and the default schema name. Note
     that you must specify the default schema name to open the
     connection.

     FIGURE GOES HERE: Add Connection Dialog

   * You can also set the port to connect with the MySQL server by
     pressing the `Advanced' button. To test connection with the MySQL
     server, set the server host name, the user name, and the password,
     and press the `Test Connection' button. If the test succeeds, the
     success confirmation dialog opens.

   * After you set all settings and test the connection, press `OK'.
     The newly created connection is displayed in Server Explorer. Now
     you can work with the MySQL server through standard Server
     Explorer GUI.

     FIGURE GOES HERE: New Data Connection

After the connection is successfully established, all settings are
saved for future use. When you start Visual Studio for the next time,
just open the connection node in Server Explorer to establish a
connection to the MySQL server again.

To modify and delete a connection, use the Server Explorer context menu
for the corresponding node. You can modify any of the settings just by
overwriting the existing values with new ones.  Note that the
connection may be modified or deleted only if no active editor for its
objects is opened: otherwise you may loose your data.


File: manual.info,  Node: connector-net-visual-studio-editing-tables,  Next: connector-net-visual-studio-editing-views,  Prev: connector-net-visual-studio-making-a-connection,  Up: connector-net-visual-studio

20.2.3.2 Editing Tables
.......................

* Menu:

* connector-net-visual-studio-editing-tables-column-editor::  Column Editor
* connector-net-visual-studio-editing-tables-indexes::  Editing Indexes
* connector-net-visual-studio-editing-tables-foreign-keys::  Editing Foreign Keys
* connector-net-visual-studio-editing-tables-column-details::  Column Properties
* connector-net-visual-studio-editing-tables-table-properties::  Table Properties

Connector/Net contains a table editor, which enables the visual
creation and modification of tables.

The Table Designer can be accessed through a mouse action on table-type
node of Server Explorer. To create a new table, right-click the
`Tables' node (under the connection node) and choose the `Create Table'
command from the context menu.

To modify an existing table, double-click the node of the table to
modify, or right-click this node and choose the `Design' item from the
context menu. Either of the commands opens the Table Designer.

The table editor is implemented in the manner of the well-known Query
Browser Table Editor, but with minor differences.

FIGURE GOES HERE: Editing New Table

Table Designer consists of the following parts:

   * Columns Editor - a data grid on top of the Table Designer. Use the
     Columns grid for column creation, modification, and deletion.

   * Indexes tab - a tab on bottom of the Table Designer. Use the
     Indexes tab for indexes management.

   * Foreign Keys tab - a tab on bottom of the Table Designer. Use the
     Foreign Keys tab for foreign keys management.

   * Column Details tab - a tab on bottom of the Table Designer.  Use
     the Column Details tab to set advanced column options.

   * Properties window - a standard Visual Studio Properties window,
     where the properties of the edited table are displayed. Use the
     Properties window to set the table properties.

Each of these areas is discussed in more detail in subsequent sections.

To save changes you have made in the Table Designer, use either `Save'
or `Save All' button of the Visual Studio main toolbar, or just press
`Control+S'. If you have not already named the table you will be
prompted to do so.

FIGURE GOES HERE: Choose Table Name

Once created you can view the table in the Server Explorer.

FIGURE GOES HERE: Newly Created Table

The Table Designer main menu enables you to set a Primary Key column,
edit Relationships such as Foreign Keys, and create Indexes.

FIGURE GOES HERE: Table Designer Main Menu


File: manual.info,  Node: connector-net-visual-studio-editing-tables-column-editor,  Next: connector-net-visual-studio-editing-tables-indexes,  Prev: connector-net-visual-studio-editing-tables,  Up: connector-net-visual-studio-editing-tables

20.2.3.3 Column Editor
......................

You can use the Column Editor to set or change the name, data type,
default value, and other properties of a table column. To set the focus
to a needed cell of a grid, use the mouse click.  Also you can move
through the grid using `Tab' and `Shift'+`Tab' keys.

To set or change the name, data type, default value and comment of a
column, activate the appropriate cell and type the desired value.

To set or unset flag-type column properties (`NOT NULL', auto
incremented, flags), check or uncheck the corresponding check boxes.
Note that the set of column flags depends on its data type.

To reorder columns, index columns or foreign key columns in the Column
Editor, select the whole column to reorder by clicking the selector
column on the left of the column grid. Then move the column by using
`Control+Up' (to move the column up) or `Control+Down' (to move the
column down) keys.

To delete a column, select it by clicking the selector column on the
left of the column grid, then press the `Delete' button on a keyboard.


File: manual.info,  Node: connector-net-visual-studio-editing-tables-indexes,  Next: connector-net-visual-studio-editing-tables-foreign-keys,  Prev: connector-net-visual-studio-editing-tables-column-editor,  Up: connector-net-visual-studio-editing-tables

20.2.3.4 Editing Indexes
........................

Indexes management is performed using the `Indexes/Keys' dialog.

To add an index, select `Table Designer', `Indexes/Keys...' from the
main menu, and click `Add' to add a new index. You can then set the
index name, index kind, index type, and a set of index columns.

FIGURE GOES HERE: Indexes Dialog

To remove an index, select it in the list box on the left, and click
the `Delete' button.

To change index settings, select the needed index in the list box on
the left. The detailed information about the index is displayed in the
panel on the right hand side. Change the desired values.


File: manual.info,  Node: connector-net-visual-studio-editing-tables-foreign-keys,  Next: connector-net-visual-studio-editing-tables-column-details,  Prev: connector-net-visual-studio-editing-tables-indexes,  Up: connector-net-visual-studio-editing-tables

20.2.3.5 Editing Foreign Keys
.............................

Foreign Keys management is performed using the `Foreign Key
Relationships' dialog.

To add a foreign key, select `Table Designer', `Relationships...' from
the main menu. This displays the `Foreign Key Relationship' dialog.
Click `Add'. You can then set the foreign key name, referenced table
name, foreign key columns, and actions upon update and delete.

To remove a foreign key, select it in the list box on the left, and
click the `Delete' button.

To change foreign key settings, select the required foreign key in the
list box on the left. The detailed information about the foreign key is
displayed in the right hand panel. Change the desired values.

FIGURE GOES HERE: Foreign Key Relationships Dialog


File: manual.info,  Node: connector-net-visual-studio-editing-tables-column-details,  Next: connector-net-visual-studio-editing-tables-table-properties,  Prev: connector-net-visual-studio-editing-tables-foreign-keys,  Up: connector-net-visual-studio-editing-tables

20.2.3.6 Column Properties
..........................

The `Column Properties' tab can be used to set column options. In
addition to the general column properties presented in the Column
Editor, in the `Column Properties' tab you can set additional
properties such as Character Set, Collation and Precision.


File: manual.info,  Node: connector-net-visual-studio-editing-tables-table-properties,  Prev: connector-net-visual-studio-editing-tables-column-details,  Up: connector-net-visual-studio-editing-tables

20.2.3.7 Table Properties
.........................

To bring up Table Properties select the table and right-click to
activate the context menu. Select `Properties'.  The `Table Properties'
dockable window will be displayed.

FIGURE GOES HERE: Table Properties Menu Item

The following table properties can be set:

   * Auto Increment

   * Average Row Length

   * Character Set

   * Collation

   * Comment

   * Data Directory

   * Index Directory

   * Maximum Rows

   * Minimum Rows

   * Name

   * Row Format

   * Schema

   * Storage Engine

The property `Schema' is read only.

FIGURE GOES HERE: Table Properties


File: manual.info,  Node: connector-net-visual-studio-editing-views,  Next: connector-net-visual-studio-editing-stored-procedures-and-functions,  Prev: connector-net-visual-studio-editing-tables,  Up: connector-net-visual-studio

20.2.3.8 Editing Views
......................

To create a new view, right-click the Views node under the connection
node in Server Explorer. From the node's context menu, choose the
`Create View' command. This command opens the SQL Editor.

FIGURE GOES HERE: Editing View SQL

You can then enter the SQL for your view.

FIGURE GOES HERE: View SQL Added

To modify an existing view, double-click a node of the view to modify,
or right-click this node and choose the `Alter View' command from a
context menu. Either of the commands opens the SQL Editor.

All other view properties can be set in the Properties window.  These
properties are:

   * Catalog

   * Check Option

   * Definer

   * Definition

   * Definer

   * Is Updateable

   * Name

   * Schema

   * Security Type

Some of these properties can have arbitrary text values, others accept
values from a predefined set. In the latter case you set the desired
value with an embedded combobox.

The properties `Is Updatable' and `Schema' are readonly.

To save changes you have made, use either `Save' or `Save All' buttons
of the Visual Studio main toolbar, or just press `Control+S'.

FIGURE GOES HERE: View SQL Saved


File: manual.info,  Node: connector-net-visual-studio-editing-stored-procedures-and-functions,  Next: connector-net-visual-studio-editing-triggers,  Prev: connector-net-visual-studio-editing-views,  Up: connector-net-visual-studio

20.2.3.9 Editing Stored Procedures and Functions
................................................

To create a new stored procedure, right-click the `Stored Procedures'
node under the connection node in Server Explorer. From the node's
context menu, choose the `Create Routine' command. This command opens
the SQL Editor.

FIGURE GOES HERE: Edit Stored Procedure SQL

To create a new stored function, right-click the `Functions' node under
the connection node in Server Explorer. From the node's context menu,
choose the `Create Routine' command.

To modify an existing stored routine (procedure or function),
double-click the node of the routine to modify, or right-click this
node and choose the `Alter Routine' command from the context menu.
Either of the commands opens the SQL Editor.

To create or alter the routine definition using SQL Editor, type this
definition in the SQL Editor using standard SQL. All other routine
properties can be set in the Properties window. These properties are:

   * Body

   * Catalog

   * Comment

   * Creation Time

   * Data Access

   * Definer

   * Definition

   * External Name

   * External Language

   * Is Deterministic

   * Last Modified

   * Name

   * Parameter Style

   * Returns

   * Schema

   * Security Type

   * Specific Name

   * SQL Mode

   * SQL Path

   * Type

Some of these properties can have arbitrary text values, others accept
values from a predefined set. In the latter case set the desired value
using the embedded combo box.

You can also set all the options directly in the SQL Editor, using the
standard `CREATE PROCEDURE' or `CREATE FUNCTION' statement. However, it
is recommended to use the Properties window instead.

To save changes you have made, use either `Save' or `Save All' buttons
of the Visual Studio main toolbar, or just press `Control+S'.

FIGURE GOES HERE: Stored Procedure SQL Saved


File: manual.info,  Node: connector-net-visual-studio-editing-triggers,  Next: connector-net-visual-studio-editing-user-defined-functions-udf,  Prev: connector-net-visual-studio-editing-stored-procedures-and-functions,  Up: connector-net-visual-studio

20.2.3.10 Editing Triggers
..........................

To create a new trigger, right-click the node of the table in which to
add the trigger. From the node's context menu, choose the `Create
Trigger' command. This command opens the SQL Editor.

To modify an existing trigger, double-click the node of the trigger to
modify, or right-click this node and choose the `Alter Trigger' command
from the context menu.  Either of the commands opens the SQL Editor.

To create or alter the trigger definition using SQL Editor, type the
trigger statement in the SQL Editor using standard SQL.

*Note*:

You should enter only the trigger statement, that is, the part of the
`CREATE TRIGGER' query that is placed after the `FOR EACH ROW' clause.

All other trigger properties are set in the Properties window.  These
properties are:

   * Definer

   * Event Manipulation

   * Name

   * Timing

Some of these properties can have arbitrary text values, others accept
values from a predefined set. In the latter case set the desired value
using the embedded combo box.

The properties `Event Table', `Schema', and `Server' in the Properties
window are read only.

To save changes you have made, use either `Save' or `Save All' buttons
of the Visual Studio main toolbar, or just press `Control+S'. Before
changes are saved, you will be asked to confirm the execution of the
corresponding SQL query in a confirmation dialog.


File: manual.info,  Node: connector-net-visual-studio-editing-user-defined-functions-udf,  Next: connector-net-visual-studio-cloning-database-objects,  Prev: connector-net-visual-studio-editing-triggers,  Up: connector-net-visual-studio

20.2.3.11 Editing User Defined Functions (UDF)
..............................................

To create a new User Defined Function (UDF), right-click the `UDFs'
node under the connection node in Server Explorer. From the node's
context menu, choose the `Create UDF' command. This command opens the
UDF Editor.

To modify an existing UDF, double-click the node of the UDF to modify,
or right-click this node and choose the `Alter UDF' command from the
context menu. Either of these commands opens the UDF Editor.

The UDF editor enables you to set the following properties:

   * Name

   * So-name (DLL name)

   * Return type

   * Is Aggregate

There are text fields for both names, a combo box for the return type,
and a check box to indicate if the UDF is aggregate. All these options
are also accessible using the Properties window.

The property `Server' in the Properties window is read only.

To save changes you have made, use either `Save' or `Save All' buttons
of the Visual Studio main toolbar, or just press `Control+S'. Before
changes are saved, you will be asked to confirm the execution of the
corresponding SQL query in a confirmation dialog.


File: manual.info,  Node: connector-net-visual-studio-cloning-database-objects,  Next: connector-net-visual-studio-dropping-database-objects,  Prev: connector-net-visual-studio-editing-user-defined-functions-udf,  Up: connector-net-visual-studio

20.2.3.12 Cloning Database Objects
..................................

Tables, views, stored procedures, and functions can be cloned using the
appropriate Clone command from the context menu: `Clone Table', `Clone
View', `Clone Routine'. The clone commands open the corresponding
editor for a new object: the `Table Editor' for cloning a table, and
the `SQL Editor' for cloning a view or a routine.

The editor is filled with values of the original object. You can modify
these values in a usual manner.

To save the cloned object, use either Save or Save All buttons of the
Visual Studio main toolbar, or just press `Control+S'. Before changes
are saved, you will be asked to confirm the execution of the
corresponding SQL query in a confirmation dialog.


File: manual.info,  Node: connector-net-visual-studio-dropping-database-objects,  Next: connector-net-visual-studio-entity-framework,  Prev: connector-net-visual-studio-cloning-database-objects,  Up: connector-net-visual-studio

20.2.3.13 Dropping Database Objects
...................................

Tables, views, stored routines, triggers, and UDFs can be dropped with
the appropriate Drop command selected from its context menu: `Drop
Table', `Drop View', `Drop Routine', `Drop Trigger', `Drop UDF'.

You will be asked to confirm the execution of the corresponding drop
query in a confirmation dialog.

Dropping of multiple objects is not supported.


File: manual.info,  Node: connector-net-visual-studio-entity-framework,  Next: connector-net-website-config,  Prev: connector-net-visual-studio-dropping-database-objects,  Up: connector-net-visual-studio

20.2.3.14 Using the ADO.NET Entity Framework
............................................

Connector/Net 6.0 introduced support for the ADO.NET Entity Framework.
ADO.NET Entity Framework was included with .NET Framework 3.5 Service
Pack 1, and Visual Studio 2008 Service Pack 1. ADO.NET Entity Framework
was released on 11th August 2008.

ADO.NET Entity Framework provides an Object Relational Mapping (ORM)
service, mapping the relational database schema to objects.  The
ADO.NET Entity Framework defines several layers, these can be
summarized as:

   * *Logical* - this layer defines the relational data and is defined
     by the Store Schema Definition Language (SSDL).

   * *Conceptual* - this layer defines the .NET classes and is defined
     by the Conceptual Schema Definition Language (CSDL)

   * *Mapping* - this layer defines the mapping from .NET classes to
     relational tables and associations, and is defined by Mapping
     Specification Language (MSL).

Connector/Net integrates with Visual Studio 2008 to provide a range of
helpful tools to assist the developer.

A full treatment of ADO.NET Entity Framework is beyond the scope of
this manual. You are encouraged to review the Microsoft ADO.NET Entity
Framework documentation
(http://msdn.microsoft.com/en-us/library/aa697427(VS.80).aspx).

Tutorials on getting started with ADO.NET Entity Framework are
available. See *Note
connector-net-tutorials-entity-framework-winform-data-source:: and
*Note
connector-net-tutorials-entity-framework-databinding-linq-entities::.


File: manual.info,  Node: connector-net-website-config,  Next: connector-net-sql-editor,  Prev: connector-net-visual-studio-entity-framework,  Up: connector-net-visual-studio

20.2.3.15 MySQL Website Configuration Tool
..........................................

MySQL Connector/Net 6.1 introduced the MySQL Website Configuration
Tool. This is a facility available in Visual Studio that enables you to
configure the Membership, Role, Session State and Profile Provider,
without having to resort to editing configuration files.  You simply
run the tool, set your configuration options, and the tool will modify
your `web.config' file accordingly.

The MySQL Website Configuration Tool appears as a small icon on the
Solution Explorer toolbar in Visual Studio, as show by the following
screenshot:

FIGURE GOES HERE: MySQL Website Configuration Tool

Clicking the Website Configuration Tool icon launches the wizard and
displays the first screen:

FIGURE GOES HERE: MySQL Website Configuration Tool - Membership

This allows you to enable use of the MySQL Membership Provider.  Simply
click the check box to enable this. You can now enter the name of the
application that you are creating the configuration for. You can also
enter a description for the application.

You can then click the `Edit...' button to launch the Connection String
Editor:

FIGURE GOES HERE: MySQL Website Configuration Tool - Connection String
Editor

Note that if you have already defined a connection string for the
providers manually in `web.config', or previously using the tool, this
will be automatically loaded and displayed, and can then be modified in
this dialog.

You can also ensure that the necessary schema are created automatically
for you by selecting the Autogenerate Schema check box. These schema
are used to store membership information. The database used to storage
is the one specified in the connection string.

You can also ensure that exceptions generated by the application will
be written to the event log by selecting the `Write exceptions to event
log' check box.

Clicking the `Advanced...' button launches a dialog that enables you to
set Membership Options. These options dictate such variables as
password length required when a user signs up, whether the password is
encrypted and whether the user can reset their password or not.

FIGURE GOES HERE: MySQL Website Configuration Tool - Advanced Options

Once information has been set up as required for configuration of the
Membership Provider the `Next' button can be clicked to display the
Roles Provider screen:

FIGURE GOES HERE: MySQL Website Configuration Tool - Roles

Again the connection string can be edited, a description added and
Autogenerate Schema can be enabled before clicking `Next' to go to the
Profiles Provider screen:

FIGURE GOES HERE: MySQL Website Configuration Tool - Profiles

This screen display similar options to the previous screens.

Click `Next' to proceed to the Session State configuration page:

FIGURE GOES HERE: MySQL Website Configuration Tool - Session State

Once you have set up the Session State Provider as required, click
`Finish' to exit the wizard.

At this point it is necessary to select the Authentication Type to From
Internet. This can be done by launching the ASP.NET Configuration Tool,
and selecting the Security tab. Click the Select authentication type
link and ensure that the From the internet radio button is selected.
You can now examine the database you created to store membership
information. All the necessary tables will have been created for you:

FIGURE GOES HERE: MySQL Website Configuration Tool - Tables


File: manual.info,  Node: connector-net-sql-editor,  Next: connector-net-ddl-t4-ef,  Prev: connector-net-website-config,  Up: connector-net-visual-studio

20.2.3.16 MySQL SQL Editor
..........................

MySQL Connector/Net 6.3.2 introduced a new MySQL SQL Editor. The
easiest way to invoke the editor is by selecting the `New', `File' menu
item from the Visual Studio main menu. This displays the `New File'
dialog:

FIGURE GOES HERE: MySQL SQL Editor - New File

From the `New File' dialog select the MySQL template, and then
double-click the `MySQL SQL Script' document, or click the `Open'
button.

The MySQL SQL Editor will be displayed. You can now enter SQL code as
required, or connect to a MySQL server. Click the `Connect to MySQL'
button in the MySQL SQL Editor toolbar. You can enter the connection
details into the `Connect to MySQL' dialog that is displayed.  You can
enter the server name, user id, password and database to connect to, or
click the `Advanced' button to select other connection string options.
Click the `Connect' button to connect to the MySQL server. It is now
possible to execute your SQL code against the server by clicking the
`Run SQL' button on the toolbar.

FIGURE GOES HERE: MySQL SQL Editor - Query

The results from any queries are displayed on the `Results' tab. Any
errors are displayed on the `Messages' tab.


File: manual.info,  Node: connector-net-ddl-t4-ef,  Prev: connector-net-sql-editor,  Up: connector-net-visual-studio

20.2.3.17 DDL T4 Template Macro
...............................

MySQL Connector/Net 6.3 introduced the ability to convert an Entity
Framework model to MySQL DDL code. Starting with a blank model, an
entity model can be developed in Visual Studio's designer. Once the
model has been created, the model's properties can be selected, and in
the Database Script Generation category of the model's properties, the
property `DDL Generation' can be found. The value `SSDLToMySQL.tt(VS)'
can then be selected from the drop-down listbox.

FIGURE GOES HERE: DDL T4 Template Macro - Model Properties

Right-clicking the model design area will display a context-sensitive
menu. Selecting `Generate Database from Model' from the menu will
display the `Generate Database Wizard'. The wizard can then be used to
generate MySQL DDL code.

FIGURE GOES HERE: DDL T4 Template Macro - Generate Database Wizard


File: manual.info,  Node: connector-net-tutorials,  Next: connector-net-programming,  Prev: connector-net-visual-studio,  Up: connector-net

20.2.4 Connector/Net Tutorials
------------------------------

* Menu:

* connector-net-tutorials-intro::  Tutorial: An Introduction to Connector/Net Programming
* connector-net-tutorials-asp-roles::  Tutorial: MySQL Connector/Net ASP.NET Membership and Role Provider
* connector-net-tutorials-asp-provider-session-state::  Tutorial: MySQL Connector/Net ASP.NET Session State Provider
* connector-net-tutorials-asp-provider-profile::  Tutorial: MySQL Connector/Net ASP.NET Profile Provider
* connector-net-tutorials-entity-framework-winform-data-source::  Tutorial: Using an Entity Framework Entity as a Windows Forms Data Source
* connector-net-tutorials-entity-framework-databinding-linq-entities::  Tutorial: Databinding in ASP.NET using LINQ on Entities
* connector-net-tutorials-ssl::  Tutorial: Using SSL with MySQL Connector/Net
* connector-net-tutorials-mysqlscript::  Tutorial: Using MySqlScript
* connector-net-tutorials-efmodel-ddl::  Tutorial: Generating MySQL DDL from an Entity Framework Model


File: manual.info,  Node: connector-net-tutorials-intro,  Next: connector-net-tutorials-asp-roles,  Prev: connector-net-tutorials,  Up: connector-net-tutorials

20.2.4.1 Tutorial: An Introduction to Connector/Net Programming
...............................................................

* Menu:

* connector-net-tutorials-connection::  The MySqlConnection Object
* connector-net-tutorials-sql-command::  The MySqlCommand Object
* connector-net-tutorials-data-adapter::  Working with Decoupled Data
* connector-net-tutorials-parameters::  Working with Parameters
* connector-net-tutorials-stored-procedures::  Working with Stored Procedures

This section provides a gentle introduction to programming with
Connector/Net. The example code is written in C#, and is designed to
work on both Microsoft .NET Framework and Mono.

This tutorial is designed to get you up and running with Connector/Net
as quickly as possible, it does not go into detail on any particular
topic. However, the following sections of this manual describe each of
the topics introduced in this tutorial in more detail. In this tutorial
you are encouraged to type in and run the code, modifying it as
required for your setup.

This tutorial assumes you have MySQL and Connector/Net already
installed. It also assumes that you have installed the World example
database, which can be downloaded from the MySQL Documentation page
(http://dev.mysql.com/doc/index-other.html). You can also find details
on how to install the database on the same page.

*Note*:

Before compiling the example code make sure that you have added
References to your project as required. The References required are
`System', `System.Data' and `MySql.Data'.


File: manual.info,  Node: connector-net-tutorials-connection,  Next: connector-net-tutorials-sql-command,  Prev: connector-net-tutorials-intro,  Up: connector-net-tutorials-intro

20.2.4.2 The MySqlConnection Object
...................................

For your Connector/Net application to connect to a MySQL database it
needs to establish a connection. This is achieved through the use of a
`MySqlConnection' object.

The MySqlConnection constructor takes a connection string as one of its
parameters. The connection string provides necessary information to
make the connection to the MySQL database. The connection string is
discussed more fully in *Note connector-net-programming-connecting::. A
reference containing a list of supported connection string options can
also be found in *Note connector-net-connection-options::.

The following code shows how to create a connection object.

     using System;
     using System.Data;

     using MySql.Data;
     using MySql.Data.MySqlClient;

     public class Tutorial1
     {
         public static void Main()
         {
             string connStr = "server=localhost;user=root;database=world;port=3306;password=******;";
             MySqlConnection conn = new MySqlConnection(connStr);
             try
             {
                 Console.WriteLine("Connecting to MySQL...");
                 conn.Open();
                 // Perform database operations
             }
             catch (Exception ex)
             {
                 Console.WriteLine(ex.ToString());
             }
             conn.Close();
             Console.WriteLine("Done.");
         }
     }

When the `MySqlConnection' constructor is invoked it returns a
connection object, which is used for subsequent database operations.
The first operation in this example is to open the connection. This
needs to be done before further operations take place. Before the
application exits the connection to the database needs to be closed by
calling `Close' on the connection object.

Sometimes an attempt to perform an `Open' on a connection object can
fail, this will generate an exception that can be handled using
standard exception handling code.

In this section you have learned how to create a connection to a MySQL
database, and open and close the corresponding connection object.


File: manual.info,  Node: connector-net-tutorials-sql-command,  Next: connector-net-tutorials-data-adapter,  Prev: connector-net-tutorials-connection,  Up: connector-net-tutorials-intro

20.2.4.3 The MySqlCommand Object
................................

Once a connection has been established with the MySQL database, the
next step is do carry out the desired database operations.  This can be
achieved through the use of the `MySqlCommand' object.

You will see how to create a `MySqlCommand' object. Once it has been
created there are three main methods of interest that you can call:

   * *ExecuteReader* - used to query the database. Results are usually
     returned in a `MySqlDataReader' object, created by `ExecuteReader'.

   * *ExecuteNonQuery* - used to insert and delete data.

   * *ExecuteScalar* - used to return a single value.

Once a `MySqlCommand' object has been created, you will call one of the
above methods on it to carry out a database operation, such as perform
a query. The results are usually returned into a `MySqlDataReader'
object, and then processed, for example the results might be displayed.
The following code demonstrates how this could be done.

     using System;
     using System.Data;

     using MySql.Data;
     using MySql.Data.MySqlClient;

     public class Tutorial2
     {
         public static void Main()
         {
             string connStr = "server=localhost;user=root;database=world;port=3306;password=******;";
             MySqlConnection conn = new MySqlConnection(connStr);
             try
             {
                 Console.WriteLine("Connecting to MySQL...");
                 conn.Open();

                 string sql = "SELECT Name, HeadOfState FROM Country WHERE Continent='Oceania'";
                 MySqlCommand cmd = new MySqlCommand(sql, conn);
                 MySqlDataReader rdr = cmd.ExecuteReader();

                 while (rdr.Read())
                 {
                     Console.WriteLine(rdr[0]+" -- "+rdr[1]);
                 }
                 rdr.Close();
             }
             catch (Exception ex)
             {
                 Console.WriteLine(ex.ToString());
             }

             conn.Close();
             Console.WriteLine("Done.");
         }
     }

When a connection has been created and opened, the code then creates a
`MySqlCommand' object. Note that the SQL query to be executed is passed
to the `MySqlCommand' constructor. The `ExecuteReader' method is then
used to generate a `MySqlReader' object. The `MySqlReader' object
contains the results generated by the SQL executed on the command
object. Once the results have been obtained in a `MySqlReader' object,
the results can be processed. In this case the information is simply
printed out as part of a `while' loop.  Finally, the `MySqlReader'
object is disposed of by running its `Close' method on it.

In the next example you will see how to use the `ExecuteNonQuery'
method.

The procedure for performing an `ExecuteNonQuery' method call is
simpler, as there is no need to create an object to store results. This
is because `ExecuteNonQuery' is only used for inserting, updating and
deleting data. The following example illustrates a simple update to the
Country table:

     using System;
     using System.Data;

     using MySql.Data;
     using MySql.Data.MySqlClient;

     public class Tutorial3
     {
         public static void Main()
         {
             string connStr = "server=localhost;user=root;database=world;port=3306;password=******;";
             MySqlConnection conn = new MySqlConnection(connStr);
             try
             {
                 Console.WriteLine("Connecting to MySQL...");
                 conn.Open();

                 string sql = "INSERT INTO Country (Name, HeadOfState, Continent) VALUES ('Disneyland','Mickey Mouse', 'North America')";
                 MySqlCommand cmd = new MySqlCommand(sql, conn);
                 cmd.ExecuteNonQuery();
             }
             catch (Exception ex)
             {
                 Console.WriteLine(ex.ToString());
             }

             conn.Close();
             Console.WriteLine("Done.");
         }
     }

The query is constructed, the command object created and the
`ExecuteNonQuery' method called on the command object. You can access
your MySQL database with the MySQL Client program and verify that the
update was carried out correctly.

Finally, you will see how the `ExecuteScalar' method can be used to
return a single value. Again, this is straightforward, as a
`MySqlDataReader' object is not required to store results, a simple
variable will do. The following code illustrates how to use
`ExecuteScalar':

     using System;
     using System.Data;

     using MySql.Data;
     using MySql.Data.MySqlClient;

     public class Tutorial4
     {
         public static void Main()
         {
             string connStr = "server=localhost;user=root;database=world;port=3306;password=******;";
             MySqlConnection conn = new MySqlConnection(connStr);
             try
             {
                 Console.WriteLine("Connecting to MySQL...");
                 conn.Open();

                 string sql = "SELECT COUNT(*) FROM Country";
                 MySqlCommand cmd = new MySqlCommand(sql, conn);
                 object result = cmd.ExecuteScalar();
                 if (result != null)
                 {
                     int r = Convert.ToInt32(result);
                     Console.WriteLine("Number of countries in the World database is: " + r);
                 }

             }
             catch (Exception ex)
             {
                 Console.WriteLine(ex.ToString());
             }

             conn.Close();
             Console.WriteLine("Done.");
         }
     }

This example uses a simple query to count the rows in the Country
table. The result is obtained by calling `ExecuteScalar' on the command
object.


File: manual.info,  Node: connector-net-tutorials-data-adapter,  Next: connector-net-tutorials-parameters,  Prev: connector-net-tutorials-sql-command,  Up: connector-net-tutorials-intro

20.2.4.4 Working with Decoupled Data
....................................

Previously, when using MySqlDataReader, the connection to the database
was continually maintained, unless explicitly closed. It is also
possible to work in a manner where a connection is only established
when needed. For example, in this mode, a connection could be
established to read a chunk of data, the data could then be modified by
the application as required. A connection could then be reestablished
only if and when the application needs to write data back to the
database. This decouples the working data set from the database.

This decouple mode of working with data is supported by Connector/Net.
There are several parts involved in allowing this method to work:

   * *Data Set* - The Data Set is the area in which data is loaded to
     read or modify it. A `DataSet' object is instantiated, which can
     store multiple tables of data.

   * *Data Adapter* - The Data Adapter is the interface between the
     Data Set and the database itself. The Data Adapter is responsible
     for efficiently managing connections to the database, opening and
     closing them as required. The Data Adapter is created by
     instantiating an object of the `MySqlDataAdapter' class. The
     `MySqlDataAdapter' object has two main methods: `Fill' which reads
     data into the Data Set, and `Update', which writes data from the
     Data Set to the database.

   * *Command Builder* - The Command Builder is a support object. The
     Command Builder works in conjunction with the Data Adapter. When a
     `MySqlDataAdapter' object is created it is typically given an
     initial SELECT statement. From this SELECT statement the Command
     Builder can work out the corresponding INSERT, UPDATE and DELETE
     statements that would be required should the database need to be
     updated. To create the Command Builder an object of the class
     `MySqlCommandBuilder' is created.

Each of these classes will now be discussed in more detail.

*Instantiating a DataSet object*

A `DataSet' object can be created simply, as shown in the following
example code snippet:

     DataSet dsCountry;
     ...
     dsCountry = new DataSet();

Although this creates the `DataSet' object it has not yet filled it
with data. For that a Data Adapter is required.

*Instantiating a MySqlDataAdapter object*

The `MySqlDataAdapter' can be created as illustrated by the following
example:

     MySqlDataAdapter daCountry;
     ...
     string sql = "SELECT Code, Name, HeadOfState FROM Country WHERE Continent='North America'";
     daCountry = new MySqlDataAdapter (sql, conn);

Note, the `MySqlDataAdapter' is given the SQL specifying the data to
work with.

*Instantiating a MySqlCommandBuilder object*

Once the `MySqlDataAdapter' has been created, it is necessary to
generate the additional statements required for inserting, updating and
deleting data. There are several ways to do this, but in this tutorial
you will see how this can most easily be done with
`MySqlCommandBuilder'. The following code snippet illustrates how this
is done:

     MySqlCommandBuilder cb = new MySqlCommandBuilder(daCountry);

Note that the `MySqlDataAdapter' object is passed as a parameter to the
command builder.

*Filling the Data Set*

To do anything useful with the data from your database, you need to
load it into a Data Set. This is one of the jobs of the
`MySqlDataAdapter' object, and is carried out with its `Fill' method.
The following example code illustrates this:

     DataSet dsCountry;
     ...
     dsCountry = new DataSet();
     ...
     daCountry.Fill(dsCountry, "Country");

Note the `Fill' method is a `MySqlDataAdapter' method, the Data Adapter
knows how to establish a connec tion with the database and retrieve the
required data, and then populates the Data Set when the `Fill' method
is called. The second parameter `Country' is the table in the Data Set
to update.

*Updating the Data Set*

The data in the Data Set can now be manipulated by the application as
required. At some point, changes to data will need to be written back
to the database. This is achieved through a `MySqlDataAdapter' method,
the `Update' method.

     daCountry.Update(dsCountry, "Country");

Again, the Data Set and the table within the Data Set to update are
specified.

*Working Example*

The interactions between the `DataSet', `MySqlDataAdapter' and
`MySqlCommandBuilder' classes can be a little confusing, so their
operation can perhaps be best illustrated by working code.

In this example, data from the World database is read into a Data Grid
View control. Here, the data can be viewed and changed before clicking
an update button. The update button then activates code to write
changes back to the database. The code uses the principles explained
above. The application was built using the Microsoft Visual Studio to
place and create the user interface controls, but the main code that
uses the key classes described above is shown below, and is portable.

     using System;
     using System.Collections.Generic;
     using System.ComponentModel;
     using System.Data;
     using System.Drawing;
     using System.Linq;
     using System.Text;
     using System.Windows.Forms;

     using MySql.Data;
     using MySql.Data.MySqlClient;

     namespace WindowsFormsApplication5
     {
         public partial class Form1 : Form
         {
             MySqlDataAdapter daCountry;
             DataSet dsCountry;

             public Form1()
             {
                 InitializeComponent();
             }

             private void Form1_Load(object sender, EventArgs e)
             {

                 string connStr = "server=localhost;user=root;database=world;port=3306;password=******;";
                 MySqlConnection conn = new MySqlConnection(connStr);
                 try
                 {
                     label2.Text = "Connecting to MySQL...";

                     string sql = "SELECT Code, Name, HeadOfState FROM Country WHERE Continent='North America'";
                     daCountry = new MySqlDataAdapter (sql, conn);
                     MySqlCommandBuilder cb = new MySqlCommandBuilder(daCountry);

                     dsCountry = new DataSet();
                     daCountry.Fill(dsCountry, "Country");
                     dataGridView1.DataSource = dsCountry;
                     dataGridView1.DataMember = "Country";
                 }
                 catch (Exception ex)
                 {
                     label2.Text = ex.ToString();
                 }
             }

             private void button1_Click(object sender, EventArgs e)
             {
                 daCountry.Update(dsCountry, "Country");
                 label2.Text = "MySQL Database Updated!";
             }

         }
     }

The application running is shown below:

FIGURE GOES HERE: World Database Application


File: manual.info,  Node: connector-net-tutorials-parameters,  Next: connector-net-tutorials-stored-procedures,  Prev: connector-net-tutorials-data-adapter,  Up: connector-net-tutorials-intro

20.2.4.5 Working with Parameters
................................

This part of the tutorial shows you how to use parameters in your
Connector/Net application.

Although it is possible to build SQL query strings directly from user
input, this is not advisable as it does not prevent erroneous or
malicious information being entered. It is safer to use parameters as
they will be processed as field data only. For example, imagine the
following query was constructed from user input:

     string sql = "SELECT Name, HeadOfState FROM Country WHERE Continent = "+user_continent;

If the string `user_continent' came from a Text Box control, there
would potentially be no control over the string entered by the user.
The user could enter a string that generates a run time error, or in
the worst case actually harms the system.  When using parameters it is
not possible to do this because a parameter is only ever treated as a
field parameter, rather than an arbitrary piece of SQL code.

The same query written user a parameter for user input would be:

     string sql = "SELECT Name, HeadOfState FROM Country WHERE Continent = @Continent";

Note that the parameter is preceded by an '@' symbol to indicate it is
to be treated as a parameter.

As well as marking the position of the parameter in the query string,
it is necessary to add a parameter to the Command object.  This is
illustrated by the following code snippet:

     cmd.Parameters.AddWithValue("@Continent", "North America");

In this example the string "North America" is supplied as the parameter
value statically, but in a more practical example it would come from a
user input control.

A further example illustrates the complete process:

     using System;
     using System.Data;

     using MySql.Data;
     using MySql.Data.MySqlClient;

     public class Tutorial5
     {
         public static void Main()
         {
             string connStr = "server=localhost;user=root;database=world;port=3306;password=******;";
             MySqlConnection conn = new MySqlConnection(connStr);
             try
             {
                 Console.WriteLine("Connecting to MySQL...");
                 conn.Open();

                 string sql = "SELECT Name, HeadOfState FROM Country WHERE Continent=@Continent";
                 MySqlCommand cmd = new MySqlCommand(sql, conn);

                 Console.WriteLine("Enter a continent e.g. 'North America', 'Europe': ");
                 string user_input = Console.ReadLine();

                 cmd.Parameters.AddWithValue("@Continent", user_input);

                 MySqlDataReader rdr = cmd.ExecuteReader();

                 while (rdr.Read())
                 {
                     Console.WriteLine(rdr["Name"]+" --- "+rdr["HeadOfState"]);
                 }
                 rdr.Close();
             }
             catch (Exception ex)
             {
                 Console.WriteLine(ex.ToString());
             }

             conn.Close();
             Console.WriteLine("Done.");
         }
     }

In this part of the tutorial you have see how to use parameters to make
your code more secure.


File: manual.info,  Node: connector-net-tutorials-stored-procedures,  Prev: connector-net-tutorials-parameters,  Up: connector-net-tutorials-intro

20.2.4.6 Working with Stored Procedures
.......................................

In this section you will see how to work with Stored Procedures.  This
section assumes you have a basic understanding of what a Stored
Procedure is, and how to create one.

For the purposes of this tutorial, you will create a simple Stored
Procedure to see how it can be called from Connector/Net. In the MySQL
Client program, connect to the World database and enter the following
Stored Procedure:

     DELIMITER //
     CREATE PROCEDURE country_hos
     (IN con CHAR(20))
     BEGIN
       SELECT Name, HeadOfState FROM Country
       WHERE Continent = con;
     END //
     DELIMITER ;

Test the Stored Procedure works as expected by typing the following
into the MySQL Client program:

     CALL country_hos('Europe');

Note that The Stored Routine takes a single parameter, which is the
continent to restrict your search to.

Having confirmed that the Stored Procedure is present and correct you
can now move on to seeing how it can be accessed from Connector/Net.

Calling a Stored Procedure from your Connector/Net application is
similar to techniques you have seen earlier in this tutorial. A
`MySqlCommand' object is created, but rather than taking an SQL query
as a parameter it takes the name of the Stored Procedure to call. The
`MySqlCommand' object also needs to be set to the type of Stored
Procedure. This is illustrated by the following code snippet:

     string rtn = "country_hos";
     MySqlCommand cmd = new MySqlCommand(rtn, conn);
     cmd.CommandType = CommandType.StoredProcedure;

In this case you also need to pass a parameter to the Stored Procedure.
This can be achieved using the techniques seen in the previous section
on parameters, *Note connector-net-tutorials-parameters::. This is
shown in the following code snippet:

     cmd.Parameters.AddWithValue("@con", "Europe");

The value of the parameter `@con' could more realistically have come
from a user input control, but for simplicity it is set as a static
string in this example.

At this point everything is set up and all that now needs to be done is
to call the routine. This can be achieved using techniques also learned
in earlier sections, but in this case the `ExecuteReader' method of the
`MySqlCommand' object is used.

Complete working code for the Stored Procedure example is shown below:

     using System;
     using System.Data;

     using MySql.Data;
     using MySql.Data.MySqlClient;

     public class Tutorial6
     {
         public static void Main()
         {
             string connStr = "server=localhost;user=root;database=world;port=3306;password=******;";
             MySqlConnection conn = new MySqlConnection(connStr);
             try
             {
                 Console.WriteLine("Connecting to MySQL...");
                 conn.Open();

                 string rtn = "country_hos";
                 MySqlCommand cmd = new MySqlCommand(rtn, conn);
                 cmd.CommandType = CommandType.StoredProcedure;

                 cmd.Parameters.AddWithValue("@con", "Europe");

                 MySqlDataReader rdr = cmd.ExecuteReader();
                 while (rdr.Read())
                 {
                     Console.WriteLine(rdr[0] + " --- " + rdr[1]);
                 }
                 rdr.Close();
             }
             catch (Exception ex)
             {
                 Console.WriteLine(ex.ToString());
             }

             conn.Close();
             Console.WriteLine("Done.");
         }
     }

In this section you have seen how to call a Stored Procedure from
Connector/Net. For the moment, this concludes our introductory tutorial
on programming with Connector/Net.


File: manual.info,  Node: connector-net-tutorials-asp-roles,  Next: connector-net-tutorials-asp-provider-session-state,  Prev: connector-net-tutorials-intro,  Up: connector-net-tutorials

20.2.4.7 Tutorial: MySQL Connector/Net ASP.NET Membership and Role Provider
...........................................................................

Many web sites feature the facility for the user to create a user
account. They can then log into the web site and enjoy a personalized
experience. This requires that the developer creates database tables to
store user information, along with code to gather and process this
data. This represents a burden on the developer, and there is the
possibility for security issues to creep into the developed code.
However, ASP.NET 2.0 introduced the Membership system. This system is
designed around the concept of Membership, Profile and Role Providers,
which together provide all of the functionality to implement a user
system, that previously would have to have been created by the
developer from scratch.

Currently, MySQL Connector/Net provides Membership, Role, Profile and
Session State Providers.

This tutorial shows you how to set up your ASP.NET web application to
use the MySQL Connector/Net Membership and Role Providers. It assumes
that you have MySQL Server installed, along with MySQL Connector/Net
and Microsoft Visual Studio. This tutorial was tested with MySQL
Connector/Net 6.0.4 and Microsoft Visual Studio 2008 Professional
Edition. It is recommended you use 6.0.4 or above for this tutorial.

  1. Create a new database in the MySQL Server using the MySQL Command
     Line Client program (`mysql'), or other suitable tool. It does not
     matter what name is used for the database, but it should be noted
     down so that it can be specified in the connection string
     constructed later in this tutorial. This database will contain the
     tables, automatically created for you later, used to store data
     about users and roles.

  2. Create a new ASP.NET Web Site in Visual Studio. If you are not
     sure how to do this, refer to the following tutorial: *Note
     connector-net-tutorials-entity-framework-databinding-linq-entities::,
     which demonstrates how to create a simple ASP.NET web site.

  3. Add References to `MySql.Data' and `MySql.Web' to the web site
     project.

  4. Locate the `machine.config' file on your system, which is the
     configuration file for the .NET Framework.

  5. Search the `machine.config' file to find the membership provider
     `MySQLMembershipProvider'.

  6. Add the attribute `autogenerateschema="true"'. The appropriate
     section should now resemble the following (note: for the sake of
     brevity some information has been excluded):

          <membership>
           <providers>
             <add name="AspNetSqlMembershipProvider"
               type="System.Web.Security.SqlMembershipProvider"
               ...
               connectionStringName="LocalSqlServer"
               ... />
             <add name="MySQLMembershipProvider"
               autogenerateschema="true"
               type="MySql.Web.Security.MySQLMembershipProvider, MySql.Web, Version=6.0.4.0, Culture=neutral, PublicKeyToken=c5687fc88969c44d"
               connectionStringName="LocalMySqlServer"
               ... />
           </providers>
          </membership>

     Note that the name for the connection string to be used to connect
     to the server that contains the membership database is
     `LocalMySqlServer'.

     The `autogenerateschema="true"' attribute will cause MySQL
     Connector/Net to silently create, or upgrade, the schema on the
     database server, to contain the required tables for storing
     membership information.

  7. It is now necessary to create the connection string referenced in
     the previous step. Load the web site's `web.config' file into
     Visual Studio.

  8. Locate the section marked `<connectionStrings>'. Add the following
     connection string information:

          <connectionStrings>
            <remove name="LocalMySqlServer"/>
            <add name="LocalMySqlServer"
                 connectionString="Datasource=localhost;Database=users;uid=root;pwd=password;"
                 providerName="MySql.Data.MySqlClient"/>
          </connectionStrings>

     The database specified is the one created in the first step.  You
     could alternatively have used an existing database.

  9. At this point build the solution to ensure no errors are present.
     This can be done by selecting `Build', `Build Solution' from the
     main menu, or pressing `F6'.

 10. ASP.NET supports the concept of locally and remotely authenticated
     users. With local authentication the user is validated using their
     Windows credentials when they attempt to access the web site. This
     can be useful in an Intranet environment. With remote
     authentication a user is prompted for their login details when
     accessing the web site, and these credentials are checked against
     the membership information stored in a database server such as
     MySQL Server. You will now see how to choose this form of
     authentication.

     Start the ASP.NET Web Site Administration Tool. This can be done
     quickly by clicking the small hammer/Earth icon in the Solution
     Explorer. You can also launch this tool by selecting `Website',
     `ASP.NET Configuration' from the main menu.

 11. In the ASP.NET Web Site Administration Tool click the `Security'
     tab.

 12. Now click the `User Authentication Type' link.

 13. Select the `From the internet' radio button. The web site will now
     need to provide a form to allow the user to enter their login
     details. These will be checked against membership information
     stored in the MySQL database.

     FIGURE GOES HERE: Authentication Type

 14. You now need to specify the Role and Membership Provider to be
     used. Click the `Provider' tab.

 15. Click the `Select a different provider for each feature
     (advanced)' link.

 16. Now select the `MySQLMembershipProvider' and the
     `MySQLRoleProvider' radio buttons.

     FIGURE GOES HERE: Select Membership and Role Provider

 17. In Visual Studio rebuild the solution by selecting `Build',
     `Rebuild Solution' from the main menu.

 18. Check that the necessary schema has been created. This can be
     achieved using the MySQL Command Line Client program.

     FIGURE GOES HERE: Membership and Role Provider Tables

 19. Assuming all is present and correct you can now create users and
     roles for your web application. The easiest way to do this is with
     the ASP.NET Web Site Administration Tool. However, many web
     applications contain their own modules for creating roles and
     users. For simplicity the ASP.NET Web Site Administration Tool
     will be used in this tutorial.

 20. In the ASP.NET Web Site Administration Tool, click the `Security'
     tab. Now that both the Membership and Role Provider are enabled
     you will see links for creating roles and users. Click the `Create
     or Manage Roles' link.

     FIGURE GOES HERE: Security Tab

 21. You can now enter the name of a new Role and click `Add Role' to
     create the new Role. Create new Roles as required.

 22. Click the `Back' button.

 23. Click the `Create User' link. You can now fill in information
     about the user to be created, and also allocate that user to one
     or more Roles.

     FIGURE GOES HERE: Create User

 24. Using the MySQL Command Line Client program you can check that
     your database has been correctly populated with the Membership and
     Role data.

     FIGURE GOES HERE: Membership and Roles Table Contents

In this tutorial you have seen how to set up the MySQL Connector/Net
Membership and Role Providers for use in your ASP.NET web application.


File: manual.info,  Node: connector-net-tutorials-asp-provider-session-state,  Next: connector-net-tutorials-asp-provider-profile,  Prev: connector-net-tutorials-asp-roles,  Up: connector-net-tutorials

20.2.4.8 Tutorial: MySQL Connector/Net ASP.NET Session State Provider
.....................................................................

MySQL Connector/Net from version 6.1 has included a MySQL Session State
Provider. This provider enables you to store session state in a MySQL
database. The following tutorial shows you how to prepare to use the
MySQL Session State Provider, and then store session data into the
MySQL database. This tutorial uses Microsoft Visual Studio 2008
Professional Edition, MySQL Connector/Net 6.1.1 and MySQL Server 5.1.
This tutorial also assumes you have created an empty database, for
example `test', where you will store session data. You could do this
using the MySQL Command Line Client tool.

  1. In Visual Studio create a new ASP.NET web site. If you are not
     sure how to do this refer to the tutorial *Note
     connector-net-tutorials-entity-framework-databinding-linq-entities::
     which demonstrates how to do this.

  2. Launch the MySQL MySQL Website Configuration tool. Due to a bug in
     6.1.1 this may not appear unless you are connected to a server in
     the Server Explorer. If you are unfamiliar with the MySQL Website
     Configuration tool it is suggested that you first work through the
     following tutorial *Note connector-net-website-config::.

  3. Navigate through the wizard to the Session State page. Make sure
     the check box `Use MySQL to manage my ASP.NET session data' is
     selected.

  4. On the same page configure the connection string to the database
     that will contain your session data. This database can be empty as
     MySQL Connector/Net will create the schema required to store
     session data.

  5. Ensure that the check box `Autogenerate Schema' is selected so
     that MySQL Connector/Net will create the schema in your database
     to store the session data correctly.

  6. Enter the name of your application.

  7. Click `Finish'. The MySQL Website Configuration tool will now
     update your application's `web.config' file with information about
     the connection string and default providers to be used. In this
     case we have selected the MySQL Session State Provider.

At this point you are ready to use the MySQL database to store session
data. To test that the set up has worked you can write a simple program
that uses session variables.

  1. Open `Default.aspx.cs'. In the Page_Load method add the following
     code:

          Session["SessionVariable1"] = "Test string";

  2. Build your solution.

  3. Run the solution (without debugging). When the application runs,
     the provider will autogenerate tables required in the database you
     chose when setting up the application.

  4. Check that the schema was in fact created. Using the MySQL Command
     Line Client use the target database and then type `SHOW TABLES;'.
     You will see that MySQL Connector/Net has created the required
     schema automatically, as we selected this to happen in the MySQL
     Website Configuration tool.

  5. Now view the contents of these tables by typing `SELECT * FROM
     my_aspnet_sessions;' in the MySQL Command Line Client. This will
     display the session data our application used. Note that this is
     stored in binary format so some data may not display as expected.

At this point you have installed the Session State Provider and carried
out a preliminary test of the installation. You will now work a bit
more with the Session State Provider.

In this part of the tutorial you will set and retrieve a session
variable. You can work with your existing project.

  1. Select the `Default.aspx' and switch to Design View. Add a text
     box and three buttons. Change the text property for the buttons to
     `Store Session Variable', `Clear Textbox', and `Show Session
     Variable'. These will be `Button1', `Button2' and `Button3'
     respectively. Build your solution to ensure that no errors have
     been introduced.

  2. Still in the Design View, double-click `Button1'. Now to the
     `Button1_Click' event handler add code some the handler resembles
     the following:

          protected void Button1_Click(object sender, EventArgs e)
          {
              Session["SessionString"] = TextBox1.Text;
          }

     You have created a new Session variable accessed using the key
     `SessionString'. This will be set to the text that was entered
     into the text box when `Button1' is clicked.

  3. In Design View double-click `Button2' to add its click event
     handler. This button needs to clear text from the text box. The
     code to do this is as follows:

          protected void Button2_Click(object sender, EventArgs e)
          {
              TextBox1.Text = "";
          }

     The code simply assigns an empty string to the `Text' property of
     the text box.

  4. In the Design View double-click `Button3' and modify the click
     handler as follows:

          protected void Button3_Click(object sender, EventArgs e)
          {
              TextBox1.Text = (String)Session["SessionString"];
          }

     This will retrieve the session string and display it in the text
     box.

  5. Now modify the `Page_Load' method as follows:

          protected void Page_Load(object sender, EventArgs e)
          {
              if (!IsPostBack)
              {
                 TextBox1.Text = "Enter some text";
              }
          }

     This ensures that when the page loads the text box `Text' property
     is reset.

  6. Ensure that the solution is saved and then rebuild the solution.

  7. Run the solution without debugging.

  8. The form will be displayed. Enter some text into the text box.
     Now click `Store Session Variable'. At this point you have stored
     the string in a session variable.

  9. Now click `Clear Text' to clear the text box.

 10. Now click `Show Session Variable' to retrieve and display the
     session variable.

 11. Refresh the page to destroy the form and display a new form.

 12. Click `Show Session Variable' the text box will display the stored
     session variable, demonstrating that the refreshing the page does
     not destroy the session variable.

This illustrates that the session state data is not destroyed when a
page is reloaded.


File: manual.info,  Node: connector-net-tutorials-asp-provider-profile,  Next: connector-net-tutorials-entity-framework-winform-data-source,  Prev: connector-net-tutorials-asp-provider-session-state,  Up: connector-net-tutorials

20.2.4.9 Tutorial: MySQL Connector/Net ASP.NET Profile Provider
...............................................................

This tutorial shows you how to use the MySQL Profile Provider to store
user profile information in a MySQL database. The tutorial uses MySQL
Connector/Net 6.1.1, MySQL Server 5.1 and Microsoft Visual Studio 2008
Professional Edition.

Many modern web sites allow the user to create a personal profile.
This requires a significant amount of code, but ASP.NET reduces this
considerable by including the functionality in its Profile classes. The
Profile Provider provides an abstraction between these classes and a
data source. The MySQL Profile Provider enables profile data to be
stored in a MySQL database. This enables the profile properties to be
written to a persistent store, and be retrieved when required. The
Profile Provider also enables profile data to be managed effectively,
for example it enables profiles that have not been accessed since a
specific date to be deleted.

The following steps show you how you can select the MySQL Profile
Provider.

  1. Create a new ASP.NET web project.

  2. Select the MySQL Website Configuration tool. Due to a bug in 6.1.1
     you may have to first connect to a server in Server Explorer
     before the tool's icon will display in the toolbar of the Solution
     Explorer.

  3. In the MySQL Website Configuration tool navigate through the tool
     to the Profiles page.

  4. Select the `Use MySQL to manage my profiles' check box.

  5. Select the `Autogenerate Schema' check box.

  6. Click the `Edit...' button and configure a connection string for
     the database that will be used to store user profile information.

  7. Navigate to the last page of the tool and click `Finish' to save
     your changes and exit the tool.

At this point you are now ready to start using the MySQL Profile
Provider. With the following steps you can carry out a preliminary test
of your installation.

  1. Open your `web.config' file.

  2. Add a simple profile such as the following:

          <system.web>
            <anonymousIdentification enabled="true"/>
            <profile defaultProvider="MySQLProfileProvider">
              ...
              <properties>
                <add name="Name" allowAnonymous="true"/>
                <add name="Age" allowAnonymous="true" type="System.UInt16"/>
                <group name="UI">
                  <add name="Color" allowAnonymous="true" defaultValue="Blue"/>
                  <add name="Style" allowAnonymous="true" defaultValue="Plain"/>
                </group>
              </properties>
            </profile>
            ...

     Note that `anonymousIdentification' has been set to true. This
     enables users who have not been authenticated to use profiles.
     They are identified by a GUID in a cookie rather than by user name.

Now that the simple profile has been defined in `web.config', the next
step is to write some code to test the profile.

  1. In Design View design a simple page with the following controls:

     FIGURE GOES HERE: Simple Profile Application

     These will allow the user to enter some profile information.  The
     user can also use the buttons to save their profile, clear the
     page, and restore their profile data.

  2. In the Code View add code as follows:

          ...
          protected void Page_Load(object sender, EventArgs e)
          {
              if (!IsPostBack)
              {
                  TextBox1.Text = Profile.Name;
                  TextBox2.Text = Profile.Age.ToString();
                  Label1.Text = Profile.UI.Color;
              }
          }

          // Store Profile
          protected void Button1_Click(object sender, EventArgs e)
          {
              Profile.Name = TextBox1.Text;
              Profile.Age = UInt16.Parse(TextBox2.Text);
          }

          // Clear Form
          protected void Button2_Click(object sender, EventArgs e)
          {
              TextBox1.Text = "";
              TextBox2.Text = "";
              Label1.Text = "";
          }

          // Retrieve Profile
          protected void Button3_Click(object sender, EventArgs e)
          {
              TextBox1.Text = Profile.Name;
              TextBox2.Text = Profile.Age.ToString();
              Label1.Text = Profile.UI.Color;
          }

          protected void DropDownList1_SelectedIndexChanged(object sender, EventArgs e)
          {
              Profile.UI.Color = DropDownList1.SelectedValue;
          }
          ...

  3. Save all files and build the solution to check that no errors have
     been introduced.

  4. Run the application.

  5. Enter your name, age and select a color from the listbox. Now
     store this information in your profile by clicking `Store
     Profile'. Note that if you do not select a color from the listbox
     your profile will use the default color `Blue' that was specified
     in the `web.config' file.

  6. Click `Clear Form' to clear text from the textboxes and the label
     that displays your chosen color.

  7. Now click `Retrieve Profile' to restore your profile data from the
     MySQL database.

  8. Now exit the browser to terminate the application.

  9. Run the application again. Note that when the page loads your
     profile information is restored from the MySQL database.

In this tutorial you have seen how to using the MySQL Profile Provider
with MySQL Connector/Net.


File: manual.info,  Node: connector-net-tutorials-entity-framework-winform-data-source,  Next: connector-net-tutorials-entity-framework-databinding-linq-entities,  Prev: connector-net-tutorials-asp-provider-profile,  Up: connector-net-tutorials

20.2.4.10 Tutorial: Using an Entity Framework Entity as a Windows Forms Data Source
...................................................................................

In this tutorial you will learn how to create a Windows Forms Data
Source from an Entity in an Entity Data Model. This tutorial assumes
that you have installed the World example database, which can be
downloaded from the MySQL Documentation page
(http://dev.mysql.com/doc/index-other.html). You can also find details
on how to install the database on the same page. It will also be
convenient for you to create a connection to the World database after
it is installed.  For instructions on how to do this see *Note
connector-net-visual-studio-making-a-connection::.

*Creating a new Windows Forms application*

The first step is to create a new Windows Forms application.

  1. In Visual Studio, select `File', `New', `Project' from the main
     menu.

  2. Choose the `Windows Forms Application' installed template. Click
     `OK'. The solution is created.

*Adding an Entity Data Model*

You will now add an Entity Data Model to your solution.

  1. In the Solution Explorer, right-click your application and select
     `Add', `New Item...'.  From `Visual Studio installed templates'
     select `ADO.NET Entity Data Model'. Click `Add'.

     FIGURE GOES HERE: Add Entity Data Model

  2. You will now see the Entity Data Model Wizard. You will use the
     wizard to generate the Entity Data Model from the world example
     database. Select the icon ` Generate from database'. Click `Next'.

     FIGURE GOES HERE: Entity Data Model Wizard Screen 1

  3. You can now select the connection you made earlier to the World
     database. If you have not already done so, you can create the new
     connection at this time by clicking `New Connection...'. For
     further instructions on creating a connection to a database see
     *Note connector-net-visual-studio-making-a-connection::.

     FIGURE GOES HERE: Entity Data Model Wizard Screen 2

  4. Make a note of the entity connection settings to be used in
     App.Config, as these will be used later to write the necessary
     control code.

  5. Click `Next'.

  6. The Entity Data Model Wizard connects to the database. You are
     then presented with a tree structure of the database. From this
     you can select the object you would like to include in your model.
     If you had created Views and Stored Routines these will be
     displayed along with any tables. In this example you just need to
     select the tables. Click `Finish' to create the model and exit the
     wizard.

     FIGURE GOES HERE: Entity Data Model Wizard Screen 3

  7. Visual Studio will generate the model and then display it.

     FIGURE GOES HERE: Entity Data Model Diagram

  8. From the Visual Studio main menu select `Build', `Build Solution',
     to ensure that everything compiles correctly so far.

*Adding a new Data Source*

You will now add a new Data Source to your project and see how it can
be used to read and write to the database.

  1. From the Visual Studio main menu select `Data', `Add New Data
     Source...'. You will be presented with the Data Source
     Configuration Wizard.

     FIGURE GOES HERE: Entity Data Source Configuration Wizard Screen 1

  2. Select the `Object' icon. Click `Next'.

  3. You will now select the Object to bind to. Expand the tree. In
     this tutorial, you will select the city table. Once the city table
     has been selected click `Next'.

     FIGURE GOES HERE: Entity Data Source Configuration Wizard Screen 2

  4. The wizard will confirm that the city object is to be added.
     Click `Finish'.

     FIGURE GOES HERE: Entity Data Source Configuration Wizard Screen 3

  5. The city object will be display in the Data Sources panel. If the
     Data Sources panel is not displayed, select `Data', `Show Data
     Sources' from the Visual Studio main menu. The docked panel will
     then be displayed.

     FIGURE GOES HERE: Data Sources

*Using the Data Source in a Windows Form*

You will now learn how to use the Data Source in a Windows Form.

  1. In the Data Sources panel select the Data Source you just created
     and drag and drop it onto the Form Designer. By default the Data
     Source object will be added as a Data Grid View control. Note that
     the Data Grid View control is bound to the `cityBindingSource' and
     the Navigator control is bound to `cityBindingNavigator'.

     FIGURE GOES HERE: Data Form Designer

  2. Save and rebuild the solution before continuing.

*Adding Code to Populate the Data Grid View*

You are now ready to add code to ensure that the Data Grid View control
will be populated with data from the City database table.

  1. Double-click the form to access its code.

  2. Add code to instatiate the Entity Data Model's EntityContainer
     object and retrieve data from the database to populate the control.

     FIGURE GOES HERE: Adding Code to the Form

  3. Save and rebuild the solution.

  4. Run the solution. Ensure the grid is populated and you can
     navigate the database.

     FIGURE GOES HERE: The Populated Grid Control

*Adding Code to Save Changes to the Database*

You will now add code to enable you to save changes to the database.

The Binding source component ensures that changes made in the Data Grid
View control are also made to the Entity classes bound to it.  However,
that data needs to be saved back from the entities to the database
itself. This can be achieved by the enabling of the Save button in the
Navigator control, and the addition of some code.

  1. In the Form Designer, click the Save icon in the Form toolbar and
     ensure that its Enabled property is set to True.

     FIGURE GOES HERE: Save Button Enabled

  2. Double-click the Save icon in the Form toolbar to display its code.

  3. You now need to add code to ensure that data is saved to the
     database when the save button is clicked in the application.

     FIGURE GOES HERE: Adding Save Code to the Form

  4. Once the code has been added, save the solution and rebuild it.
     Run the application and verify that changes made in the grid are
     saved.


File: manual.info,  Node: connector-net-tutorials-entity-framework-databinding-linq-entities,  Next: connector-net-tutorials-ssl,  Prev: connector-net-tutorials-entity-framework-winform-data-source,  Up: connector-net-tutorials

20.2.4.11 Tutorial: Databinding in ASP.NET using LINQ on Entities
.................................................................

In this tutorial you create an ASP.NET web page that binds LINQ queries
to entities using the Entity Framework mapping.

If you have not already done so, you should install the World example
database prior to attempting this tutorial. Instructions on where to
obtain the database and instructions on how to install it where given
in the tutorial *Note
connector-net-tutorials-entity-framework-winform-data-source::.

*Creating an ASP.NET web site*

In this part of the tutorial you will create an ASP.NET web site.  The
web site will use the World database. The main web page will feature a
drop down list from which you can select a country, data about that
country's cities will then be displayed in a grid view control.

  1. From the Visual Studio main menu select `File', `New', `Web
     Site...'.

  2. From the Visual Studio installed templates select `ASP.NET Web
     Site'. Click `OK'. You will be presented with the Source view of
     your web page by default.

  3. Click the Design view tab situated underneath the Source view
     panel.

     FIGURE GOES HERE: The Design Tab

  4. In the Design view panel, enter some text to decorate the blank
     web page.

  5. Click Toolbox. From the list of controls select `DropDownList'.
     Drag and drop the control to a location beneath the text on your
     web page.

     FIGURE GOES HERE: Drop Down List

  6. From the `DropDownList' control's context menu, ensure that the
     `Enable AutoPostBack' check box is enabled. This will ensure the
     control's event handler is called when an item is selected. The
     user's choice will in turn be used to populate the `GridView'
     control.

     FIGURE GOES HERE: Enable AutoPostBack

  7. From the Toolbox select the `GridView' control.

     FIGURE GOES HERE: Grid View Control

     Drag and drop the Grid Vew control to a location just below the
     Drop Down List you already placed.

     FIGURE GOES HERE: Placed Grid Vew Control

  8. At this point it is recommended that you save your solution, and
     build the solution to ensure that there are no errors.

  9. If you run the solution you will see that the text and drop down
     list are displayed, but the list is empty. Also, the grid view
     does not appear at all. Adding this functionality is described in
     the following sections.

At this stage you have a web site that will build, but further
functionality is required. The next step will be to use the Entity
Framework to create a mapping from the World database into entities
that you can control programmatically.

*Creating an ADO.NET Entity Data Model*

In this stage of the tutorial you will add an ADO.NET Entity Data Model
to your project, using the World database at the storage level. The
procedure for doing this is described in the tutorial *Note
connector-net-tutorials-entity-framework-winform-data-source::, and so
will not be repeated here.

*Populating a Drop Data List Box with using the results of a entity
LINQ query*

In this part of the tutorial you will write code to populate the
DropDownList control. When the web page loads the data to populate the
list will be achieved by using the results of a LINQ query on the model
created previously.

  1. In the Design view panel, double-click any blank area. This brings
     up the Page_Load method.

  2. Modify the relevant section of code according to the following
     listing:

          ...
          public partial class _Default : System.Web.UI.Page
          {
              worldModel.worldEntities we;

              protected void Page_Load(object sender, EventArgs e)
              {
                  we = new worldModel.worldEntities();

                  if (!IsPostBack)
                  {
                      var countryQuery = from c in we.country
                                         orderby c.Name
                                         select new { c.Code, c.Name };
                      DropDownList1.DataValueField = "Code";
                      DropDownList1.DataTextField = "Name";
                      DropDownList1.DataSource = countryQuery;
                      DataBind();
                  }
              }
          ...

     Note that the list control only needs to be populated when the
     page first loads. The conditional code ensures that if the page is
     subsequently reloaded, the list control is not repopulated, which
     would cause the user selection to be lost.

  3. Save the solution, build it and run it. You should see the list
     control has been populated. You can select an item, but as yet the
     grid view control does not appear.

At this point you have a working Drop Down List control, populated by a
LINQ query on your entity data model.

*Populating a Grid View control using an entity LINQ query*

In the last part of this tutorial you will populate the Grid View
Control using a LINQ query on your entity data model.

  1. In the Design view, double-click the `DropDownList' control. This
     causes its SelectedIndexChanged code to be displayed. This method
     is called when a user selects an item in the list control and thus
     fires an AutoPostBack event.

  2. Modify the relevant section of code accordingly to the following
     listing:

          ...
              protected void DropDownList1_SelectedIndexChanged(object sender, EventArgs e)
              {
                  var cityQuery = from c in we.city
                                  where c.CountryCode == DropDownList1.SelectedValue
                                  orderby c.Name
                                  select new { c.Name, c.Population, c.CountryCode };
                  GridView1.DataSource = cityQuery;
                  DataBind();
              }
          ...

     The grid view control is populated from the result of the LINQ
     query on the entity data model.

  3. As a check compare your code to that shown in the following
     screenshot:

     FIGURE GOES HERE: Source Code

  4. Save, build and run the solution. As you select a country you will
     see its cities are displayed in the grid view control.

     FIGURE GOES HERE: The Working Web Site

In this tutorial you have seen how to create an ASP.NET web site, you
have also seen how you can access a MySQL database using LINQ queries
on an entity data model.


File: manual.info,  Node: connector-net-tutorials-ssl,  Next: connector-net-tutorials-mysqlscript,  Prev: connector-net-tutorials-entity-framework-databinding-linq-entities,  Up: connector-net-tutorials

20.2.4.12 Tutorial: Using SSL with MySQL Connector/Net
......................................................

In this tutorial you will learn how you can use MySQL Connector/Net to
connect to a MySQL server configured to use SSL. Support for SSL client
certificates was added with MySQL Connector/Net 6.2.

MySQL Server uses the PEM format for certificates and private keys.
This tutorial will use the test certificates from the server test suite
by way of example. You can obtain the MySQL Server source code from
MySQL Downloads (http://dev.mysql.com/downloads/mysql/5.1.html#source).
The certificates can be found in the directory `./mysql-test/std_data'.

To carry out the steps in this tutorial, you must have Open SSL
installed. This can be downloaded for Microsoft Windows at no charge
from Shining Light Productions
(http://www.slproweb.com/products/Win32OpenSSL.html).

Further details on the connection string options used in this tutorial
can be found at *Note connector-net-connection-options::.

*Configuring the MySQL Server to use SSL*

  1. In the MySQL Server configuration file, set the SSL parameters as
     follows:

          ssl-ca=path/to/repo/mysql-test/std_data/cacert.pem
          ssl-cert=path/to/repo/mysql-test/std_data/server-cert.pem
          ssl-key=path/to/repo/mysql-test/std_data/server-key.pem

     Adjust the directories according to the location in which you
     installed the MySQL source code.

  2. In this step you create a test user and set the user to require
     SSL.

     Using the MySQL Command Line Client, connect as root and create
     the user `sslclient'.

  3. To set privileges and requirements, issue the following command:

          GRANT ALL PRIVILEGES ON *.* TO sslclient@'%' REQUIRE SSL;

* Creating a certificate file to use with the .NET client*

  1. The .NET client does not use the PEM file format, as .NET does not
     support this format natively. You will be using test client
     certificates from the same server repository, for the purposes of
     this example. Convert these to PFX format first. This format is
     also known as PKCS#12. An article describing this procedure can be
     found at the Citrix website
     (http://support.citrix.com/article/CTX106630). From the directory
     `SERVER-REPOSITORY-ROOT/mysql-test/std_data', issue the following
     command:

          openssl pkcs12 -export -in client-cert.pem -inkey client-key.pem -certfile cacert.pem -out client.pfx

  2. When asked for an export password, enter the password `pass'. The
     file `client.pfx' will be generated. This file is used in the
     remainder of the tutorial.

*Connecting to the server using a file-based certificate*

  1. You will use PFX file, `client.pfx' you created in the previous
     step to authenticate the client. The following example
     demonstrates how to connect using the `SSL Mode', `CertificateFile'
     and `CertificatePassword' connection string options:

          using (MySqlConnection connection = new MySqlConnection(
            "database=test;user=sslclient;" +
            "CertificateFile=H:\\bzr\\mysql-trunk\\mysqlest\\std_data\\client.pfx" +
            "CertificatePassword=pass;" +
            "SSL Mode=Required "))
          {
              connection.Open();
          }

     The path to the certificate file will need to be changed to
     reflect your individual installation.

*Connecting to the server using a store-based certificate*

  1. The first step is to import the PFX file, `client.pfx', into the
     Personal Store.  Double-click the file in Windows explorer. This
     launches the Certificate Import Wizard.

  2. Follow the steps dictated by the wizard, and when prompted for the
     password for the PFX file, enter `pass'.

  3. Click `Finish' to close the wizard and import the certificate into
     the personal store.

*Examine certificates in the Personal Store*

  1. Start the Microsoft Management Console by entering `mmc.exe' at a
     command prompt.

  2. Select `File', `Add/Remove snap-in'. Click `Add'. Select
     `Certificates' from the list of available snap-ins in the dialog.

  3. Click `Add' button in the dialog, and select the `My user account'
     radio button.  This is used for personal certificates.

  4. Click the `Finish' button.

  5. Click `OK' to close the Add/Remove Snap-in dialog.

  6. You will now have `Certificates - Current User' displayed in the
     left panel of the Microsoft Management Console. Expand the
     Certificates - Current User tree item and select `Personal',
     `Certificates'. The right-hand panel will display a certificate
     issued to MySQL. This is the certificate that was previously
     imported. Double-click the certificate to display its details.

  7. After you have imported the certificate to the Personal Store, you
     can use a more succint connection string to connect to the
     database, as illustrated by the following code:

          using (MySqlConnection connection = new MySqlConnection(
             "database=test;user=sslclient;" +
             "Certificate Store Location=CurrentUser;" +
             "SSL Mode=Required"))
          {
             connection.Open();
          }

*Certificate Thumbprint Parameter*

If you have a large number of certificates in your store, and many have
the same Issuer, this can be a source of confusion and result in the
wrong certificate being used. To alleviate this situation, there is an
optional Certificate Thumbprint parameter that can additionally be
specified as part of the connection string. As mentioned before, you
can double-click a certificate in the Microsoft Management Console to
display the certificate's details.  When the Certificate dialog is
displayed click the `Details' tab and scroll down to see the
thumbprint. The thumbprint will typically be a number such as `‎47 94
36 00 9a 40 f3 01 7a 14 5c f8 47 9e 76 94 d7 aa de f0'. This thumbprint
can be used in the connection string, as the following code illustrates:

     using (MySqlConnection connection = new MySqlConnection(
           "database=test;user=sslclient;" +
           "Certificate Store Location=CurrentUser;" +
           "Certificate Thumbprint=479436009a40f3017a145cf8479e7694d7aadef0;"+
           "SSL Mode=Required"))
     {
         connection.Open();
     }

Spaces in the thumbprint parameter are optional and the value is
case-insensitive.


File: manual.info,  Node: connector-net-tutorials-mysqlscript,  Next: connector-net-tutorials-efmodel-ddl,  Prev: connector-net-tutorials-ssl,  Up: connector-net-tutorials

20.2.4.13 Tutorial: Using MySqlScript
.....................................

* Menu:

* connector-net-tutorials-mysqlscript-delimiter::  Using Delimiters with MySqlScript

This tutorial teaches you how to use the MySqlScript class. This class
enables you to execute a series of statements. Depending on the
circumstances, this can be more convenient than using the MySqlCommand
approach.

Further details of the MySqlScript class can be found in the reference
documentation supplied with MySQL Connector/Net.

To run the example programs in this tutorial, set up a simple test
database and table using the *Note `mysql': mysql. Command Line Client
or MySQL Workbench. Commands for the *Note `mysql': mysql.  Command
Line Client are given here:

  1. `CREATE DATABASE TestDB;'

  2. `USE TestDB;'

  3. `CREATE TABLE TestTable (id INT NOT NULL PRIMARY KEY
     AUTO_INCREMENT, name VARCHAR(100));'

The main method of the MySqlScript class is the Execute method. This
method causes the script (sequence of statements) assigned to the Query
property of the MySqlScript object to be executed. Note the Query
property can be set through the MySqlScript constructor or using the
Query property.  Execute returns the number of statements executed.

The MySqlScript object will execute the specified script on the
connection set using the Connection property. Again, this property can
be set directly or through the MySqlScript constructor. The following
code snippets illustrate this:

     string sql = "SELECT * FROM TestTable";
     ...
     MySqlScript script = new MySqlScript(conn, sql);
     ...
     MySqlScript script = new MySqlScript();
     script.Query = sql;
     script.Connection = conn;
     ...
     script.Execute();

The MySqlScript class has several events associated with it. There are:

  1. Error - generated in an error occurs.

  2. ScriptCompleted - generated when the script successfully completes
     execution.

  3. StatementExecuted - generated after each statement is executed.

It is possible to assign event handlers to each of these events.  These
user-provided routines will be called back should the connected event
occur. The following code shows how the event handlers are set up.

     script.Error += new MySqlScriptErrorEventHandler(script_Error);
     script.ScriptCompleted += new EventHandler(script_ScriptCompleted);
     script.StatementExecuted += new MySqlStatementExecutedEventHandler(script_StatementExecuted);

In VisualStudio you can use tab completion to fill out stub routines
for you, to save typing. To do this start by typing, for example,
`script.Error +='. Then press `TAB', and then press `TAB' again. The
assignment will be completed, and a stub event handler created. A
complete working example is shown below:

     using System;
     using System.Collections.Generic;
     using System.Linq;
     using System.Text;

     using System.Data;
     using MySql.Data;
     using MySql.Data.MySqlClient;

     namespace MySqlScriptTest
     {
         class Program
         {
             static void Main(string[] args)
             {
                 string connStr = "server=localhost;user=root;database=TestDB;port=3306;password=******;";
                 MySqlConnection conn = new MySqlConnection(connStr);

                 try
                 {
                     Console.WriteLine("Connecting to MySQL...");
                     conn.Open();

                     string sql = "INSERT INTO TestTable(name) VALUES ('Superman');" +
                                  "INSERT INTO TestTable(name) VALUES ('Batman');" +
                                  "INSERT INTO TestTable(name) VALUES ('Wolverine');" +
                                  "INSERT INTO TestTable(name) VALUES ('Storm');";

                     MySqlScript script = new MySqlScript(conn, sql);

                     script.Error += new MySqlScriptErrorEventHandler(script_Error);
                     script.ScriptCompleted += new EventHandler(script_ScriptCompleted);
                     script.StatementExecuted += new MySqlStatementExecutedEventHandler(script_StatementExecuted);

                     int count = script.Execute();

                     Console.WriteLine("Executed " + count + " statement(s).");
                     Console.WriteLine("Delimiter: " + script.Delimiter);
                 }
                 catch (Exception ex)
                 {
                     Console.WriteLine(ex.ToString());
                 }

                 conn.Close();
                 Console.WriteLine("Done.");
             }

             static void script_StatementExecuted(object sender, MySqlScriptEventArgs args)
             {
                 Console.WriteLine("script_StatementExecuted");
             }

             static void script_ScriptCompleted(object sender, EventArgs e)
             {
                 /// EventArgs e will be EventArgs.Empty for this method
                 Console.WriteLine("script_ScriptCompleted!");
             }

             static void script_Error(Object sender, MySqlScriptErrorEventArgs args)
             {
                 Console.WriteLine("script_Error: " + args.Exception.ToString());
             }
         }
     }

Note that in the script_ScriptCompleted event handler, the EventArgs
parameter `e' will be `EventArgs.Empty'. In the case of the
`ScriptCompleted' event there is no additional data to be obtained,
which is why the event object is `EventArgs.Empty'.


File: manual.info,  Node: connector-net-tutorials-mysqlscript-delimiter,  Prev: connector-net-tutorials-mysqlscript,  Up: connector-net-tutorials-mysqlscript

20.2.4.14 Using Delimiters with MySqlScript
...........................................

Depending on the nature of the script, you made need control of the
delimiter used to separate the statements that will make up a script.
The most common example of this is where you have a multi-statement
stored routine as part of your script. In this case if the default
delimiter of `;' is used you will get an error when you attempt to
execute the script. For example, consider the following stored routine:

     CREATE PROCEDURE test_routine()
     BEGIN
         SELECT name FROM TestTable ORDER BY name;
         SELECT COUNT(name) FROM TestTable;
     END

This routine actually needs to be executed on the MySQL Server as a
single statement. However, with the default delimiter of `;', the
MySqlScript class would interpret the above as two statements, the
first being:

     CREATE PROCEDURE test_routine()
     BEGIN
         SELECT name FROM TestTable ORDER BY name;

Executing this as a statement would generate an error. To solve this
problem MySqlScript supports the ability to set a different delimiter.
This is achieved through the Delimiter property. For example, you could
set the delimiter to `??', in which case the above stored routine would
no longer generate an error when executed.  Multiple statements can be
delimited in the script, so for example, you could have a three
statement script such as:

     string sql = "DROP PROCEDURE IF EXISTS test_routine??" +
                  "CREATE PROCEDURE test_routine() " +
                  "BEGIN " +
                  "SELECT name FROM TestTable ORDER BY name;" +
                  "SELECT COUNT(name) FROM TestTable;" +
                  "END??" +
                  "CALL test_routine()";

You can change the delimiter back at any point by setting the Delimiter
property. The following code shows a complete working example:

     using System;
     using System.Collections.Generic;
     using System.Linq;
     using System.Text;

     using MySql.Data;
     using MySql.Data.MySqlClient;

     namespace ConsoleApplication8
     {
         class Program
         {
             static void Main(string[] args)
             {
                 string connStr = "server=localhost;user=root;database=TestDB;port=3306;password=******;";
                 MySqlConnection conn = new MySqlConnection(connStr);

                 try
                 {
                     Console.WriteLine("Connecting to MySQL...");
                     conn.Open();

                     string sql =    "DROP PROCEDURE IF EXISTS test_routine??" +
                                     "CREATE PROCEDURE test_routine() " +
                                     "BEGIN " +
                                     "SELECT name FROM TestTable ORDER BY name;" +
                                     "SELECT COUNT(name) FROM TestTable;" +
                                     "END??" +
                                     "CALL test_routine()";

                     MySqlScript script = new MySqlScript(conn);

                     script.Query = sql;
                     script.Delimiter = "??";
                     int count = script.Execute();
                     Console.WriteLine("Executed " + count + " statement(s)");
                     script.Delimiter = ";";
                     Console.WriteLine("Delimiter: " + script.Delimiter);
                     Console.WriteLine("Query: " + script.Query);
                 }
                 catch (Exception ex)
                 {
                     Console.WriteLine(ex.ToString());
                 }

                 conn.Close();
                 Console.WriteLine("Done.");
             }
         }
     }


File: manual.info,  Node: connector-net-tutorials-efmodel-ddl,  Prev: connector-net-tutorials-mysqlscript,  Up: connector-net-tutorials

20.2.4.15 Tutorial: Generating MySQL DDL from an Entity Framework Model
.......................................................................

In this tutorial, you will learn how to create MySQL DDL from an Entity
Framework model. Use Visual Studio 2010 and MySQL Connector/Net 6.3 to
carry out this tutorial.

  1. Create a new console application in Visual Studio 2010.

  2. Using the `Solution Explorer', add a reference to
     `MySql.Data.Entity'.

  3. From the `Solution Explorer' select `Add', `New Item'. In the `Add
     New Item' dialog select `Online Templates'. Select `ADO.NET Entity
     Data Model' and click `Add'. The `Entity Data Model' dialog will
     be displayed.

  4. In the `Entity Data Model' dialog select `Empty Model'. Click
     `Finish'. A blank model will be created.

  5. Create a simple model. A single Entity will do for the purposes of
     this tutorial.

  6. In the `Properties' panel select `ConceptualEntityModel' from the
     drop-down listbox.

  7. In the `Properties' panel, locate the `DDL Generation Template' in
     the category `Database Script Generation'.

  8. For the `DDL Generation' property select `SSDLToMySQL.tt(VS)' from
     the drop-down listbox.

  9. Save the solution.

 10. Right-click an empty space in the model design area. The
     context-sensitive menu will be displayed.

 11. From the context-sensitive menu select `Generate Database from
     Model'. The `Generate Database Wizard' dialog will be displayed.

 12. In the `Generate Database Wizard' dialog select an existing
     connection, or create a new connection to a server. Select an
     appropriate radio button to show or hide sensitive data. For the
     purposes of this tutorial you can select `Yes' (although you might
     skip this for commercial applications).

 13. Click `Next'. MySQL compatible DDL code will be generated. Click
     `Finish' to exit the wizard.

You have seen how to create MySQL DDL code from an Entity Framework
model.


File: manual.info,  Node: connector-net-programming,  Next: connector-net-connection-options,  Prev: connector-net-tutorials,  Up: connector-net

20.2.5 Connector/Net Programming
--------------------------------

* Menu:

* connector-net-programming-connecting::  Connecting to MySQL Using Connector/Net
* connector-net-programming-connecting-connection-string::  Creating a Connection String
* connector-net-programming-mysqlcommand::  Using MySqlCommand
* connector-net-programming-connection-pooling::  Using Connector/Net with Connection Pooling
* connector-net-programming-prepared::  Using the Connector/Net with Prepared Statements
* connector-net-programming-stored::  Accessing Stored Procedures with Connector/Net
* connector-net-programming-blob::  Handling BLOB Data With Connector/Net
* connector-net-programming-crystal::  Using Connector/Net with Crystal Reports
* connector-net-programming-datetime::  Handling Date and Time Information in Connector/Net
* connector-net-programming-asp-provider::  ASP.NET Provider Model
* connector-net-programming-binary-issues::  Binary/Nonbinary Issues
* connector-net-using-character-sets::  Character Sets
* connector-net-medium-trust::   Working with medium trust
* connector-net-programming-tracing::  Using the MySQL Connector/Net Trace Source Object
* connector-net-programming-bulk-loader::  Using the Bulk Loader

Connector/Net comprises several classes that are used to connect to the
database, execute queries and statements, and manage query results.

The following are the major classes of Connector/Net:

   * `MySqlCommand': Represents an SQL statement to execute against a
     MySQL database.

   * `MySqlCommandBuilder': Automatically generates single-table
     commands used to reconcile changes made to a DataSet with the
     associated MySQL database.

   * `MySqlConnection': Represents an open connection to a MySQL Server
     database.

   * `MySqlDataAdapter': Represents a set of data commands and a
     database connection that are used to fill a data set and update a
     MySQL database.

   * `MySqlDataReader': Provides a means of reading a forward-only
     stream of rows from a MySQL database.

   * `MySqlException': The exception that is thrown when MySQL returns
     an error.

   * `MySqlHelper': Helper class that makes it easier to work with the
     provider.

   * `MySqlTransaction': Represents an SQL transaction to be made in a
     MySQL database.

In the following sections you will learn about some common use cases
for Connector/Net, including BLOB handling, date handling, and using
Connector/Net with common tools such as Crystal Reports.


File: manual.info,  Node: connector-net-programming-connecting,  Next: connector-net-programming-connecting-connection-string,  Prev: connector-net-programming,  Up: connector-net-programming

20.2.5.1 Connecting to MySQL Using Connector/Net
................................................

*Introduction*

All interaction between a .NET application and the MySQL server is
routed through a `MySqlConnection' object. Before your application can
interact with the server, a `MySqlConnection' object must be instanced,
configured, and opened.

Even when using the `MySqlHelper' class, a `MySqlConnection' object is
created by the helper class.

In this section, we will describe how to connect to MySQL using the
`MySqlConnection' object.


File: manual.info,  Node: connector-net-programming-connecting-connection-string,  Next: connector-net-programming-mysqlcommand,  Prev: connector-net-programming-connecting,  Up: connector-net-programming

20.2.5.2 Creating a Connection String
.....................................

* Menu:

* connector-net-programming-connecting-open::  Opening a Connection
* connector-net-programming-connecting-errors::  Handling Connection Errors
* connector-net-programming-getschema::  Using GetSchema on a Connection

The `MySqlConnection' object is configured using a connection string. A
connection string contains sever key/value pairs, separated by
semicolons. Each key/value pair is joined with an equal sign.

The following is a sample connection string:

     Server=127.0.0.1;Uid=root;Pwd=12345;Database=test;

In this example, the `MySqlConnection' object is configured to connect
to a MySQL server at `127.0.0.1', with a user name of `root' and a
password of `12345'. The default database for all statements will be
the `test' database. All other options may be found here: *Note
connector-net-connection-options::.

*Note*:

Using the '@' symbol for parameters is now the preferred approach
although the old pattern of using '?' is still supported.

Please be aware however that using '@' can cause conflicts when user
variables are also used. To help with this situation please see the
documentation on the `Allow User Variables' connection string option,
which can be found here: *Note connector-net-connection-options::. The
`Old Syntax' connection string option has now been deprecated.


File: manual.info,  Node: connector-net-programming-connecting-open,  Next: connector-net-programming-connecting-errors,  Prev: connector-net-programming-connecting-connection-string,  Up: connector-net-programming-connecting-connection-string

20.2.5.3 Opening a Connection
.............................

Once you have created a connection string it can be used to open a
connection to the MySQL server.

The following code is used to create a `MySqlConnection' object, assign
the connection string, and open the connection.

Visual Basic Example

     Dim conn As New MySql.Data.MySqlClient.MySqlConnection
     Dim myConnectionString as String

     myConnectionString = "server=127.0.0.1;" _
                 & "uid=root;" _
                 & "pwd=12345;" _
                 & "database=test;"

     Try
       conn.ConnectionString = myConnectionString
       conn.Open()

     Catch ex As MySql.Data.MySqlClient.MySqlException
       MessageBox.Show(ex.Message)
     End Try

C# Example

     MySql.Data.MySqlClient.MySqlConnection conn;
     string myConnectionString;

     myConnectionString = "server=127.0.0.1;uid=root;" +
         "pwd=12345;database=test;";

     try
     {
         conn = new MySql.Data.MySqlClient.MySqlConnection();
         conn.ConnectionString = myConnectionString;
         conn.Open();
     }
     catch (MySql.Data.MySqlClient.MySqlException ex)
     {
         MessageBox.Show(ex.Message);
     }

You can also pass the connection string to the constructor of the
`MySqlConnection' class:

Visual Basic Example

     Dim myConnectionString as String

     myConnectionString = "server=127.0.0.1;" _
                   & "uid=root;" _
                   & "pwd=12345;" _
                   & "database=test;"

     Try
         Dim conn As New MySql.Data.MySqlClient.MySqlConnection(myConnectionString)
         conn.Open()
     Catch ex As MySql.Data.MySqlClient.MySqlException
        MessageBox.Show(ex.Message)
     End Try

C# Example

     MySql.Data.MySqlClient.MySqlConnection conn;
     string myConnectionString;

     myConnectionString = "server=127.0.0.1;uid=root;" +
         "pwd=12345;database=test;";

     try
     {
         conn = new MySql.Data.MySqlClient.MySqlConnection(myConnectionString);
         conn.Open();
     }
     catch (MySql.Data.MySqlClient.MySqlException ex)
     {
         MessageBox.Show(ex.Message);
     }

Once the connection is open it can be used by the other Connector/Net
classes to communicate with the MySQL server.


File: manual.info,  Node: connector-net-programming-connecting-errors,  Next: connector-net-programming-getschema,  Prev: connector-net-programming-connecting-open,  Up: connector-net-programming-connecting-connection-string

20.2.5.4 Handling Connection Errors
...................................

Because connecting to an external server is unpredictable, it is
important to add error handling to your .NET application. When there is
an error connecting, the `MySqlConnection' class will return a
`MySqlException' object. This object has two properties that are of
interest when handling errors:

   * `Message': A message that describes the current exception.

   * `Number': The MySQL error number.

When handling errors, you can your application's response based on the
error number. The two most common error numbers when connecting are as
follows:

   * `0': Cannot connect to server.

   * `1045': Invalid user name and/or password.

The following code shows how to adapt the application's response based
on the actual error:

Visual Basic Example

     Dim myConnectionString as String

     myConnectionString = "server=127.0.0.1;" _
               & "uid=root;" _
               & "pwd=12345;" _
               & "database=test;"

     Try
         Dim conn As New MySql.Data.MySqlClient.MySqlConnection(myConnectionString)
         conn.Open()
     Catch ex As MySql.Data.MySqlClient.MySqlException
         Select Case ex.Number
             Case 0
                 MessageBox.Show("Cannot connect to server. Contact administrator")
             Case 1045
                 MessageBox.Show("Invalid username/password, please try again")
         End Select
     End Try

C# Example

     MySql.Data.MySqlClient.MySqlConnection conn;
     string myConnectionString;

     myConnectionString = "server=127.0.0.1;uid=root;" +
         "pwd=12345;database=test;";

     try
     {
         conn = new MySql.Data.MySqlClient.MySqlConnection(myConnectionString);
         conn.Open();
     }
         catch (MySql.Data.MySqlClient.MySqlException ex)
     {
         switch (ex.Number)
         {
             case 0:
                 MessageBox.Show("Cannot connect to server.  Contact administrator");
             case 1045:
                 MessageBox.Show("Invalid username/password, please try again");
         }
     }

*Important*:

Note that if you are using multilanguage databases you must specify the
character set in the connection string. If you do not specify the
character set, the connection defaults to the `latin1' charset. You can
specify the character set as part of the connection string, for example:

     MySqlConnection myConnection = new MySqlConnection("server=127.0.0.1;uid=root;" +
         "pwd=12345;database=test;Charset=latin1;");


File: manual.info,  Node: connector-net-programming-getschema,  Prev: connector-net-programming-connecting-errors,  Up: connector-net-programming-connecting-connection-string

20.2.5.5 Using GetSchema on a Connection
........................................

* Menu:

* connector-net-programming-getschema-collections::  Collections

The `GetSchema()' method of the connection object can be used to
retrieve schema information about the database currently connected to.
The schema information is returned in the form of a `DataTable'. The
schema information is organized into a number of collections.
Different forms of the `GetSchema()' method can be used depending on
the information required. There are three forms of the `GetSchema()'
method:

   * `GetSchema()' - This call will return a list of available
     collections.

   * `GetSchema(String)' - This call returns information about the
     collection named in the string parameter. If the string
     `MetaDataCollections' is used then a list of all available
     collections is returned. This is the same as calling `GetSchema()'
     without any parameters.

   * `GetSchema(String, String[])' - In this call the first string
     parameter represents the collection name, and the second parameter
     represents a string array of restriction values. Restriction
     values limit the amount of data that will be returned. Restriction
     values are explained in more detail in the Microsoft .NET
     documentation
     (http://msdn.microsoft.com/en-us/library/ms254934(VS.80).aspx).


File: manual.info,  Node: connector-net-programming-getschema-collections,  Prev: connector-net-programming-getschema,  Up: connector-net-programming-getschema

20.2.5.6 Collections
....................

The collections can be broadly grouped into two types: collections that
are common to all data providers, and collections specific to a
particular provider.

*Common*

The following collections are common to all data providers:

   * MetaDataCollections

   * DataSourceInformation

   * DataTypes

   * Restrictions

   * ReservedWords

*Provider-specific*

The following are the collections currently provided by MySQL
Connector/Net, in addition to the common collections above:

   * Databases

   * Tables

   * Columns

   * Users

   * Foreign Keys

   * IndexColumns

   * Indexes

   * Foreign Key Columns

   * UDF

   * Views

   * ViewColumns

   * Procedure Parameters

   * Procedures

   * Triggers

*Example Code*

A list of available collections can be obtained using the following
code:

     using System;
     using System.Data;
     using System.Text;
     using MySql.Data;
     using MySql.Data.MySqlClient;

     namespace ConsoleApplication2
     {
         class Program
         {

             private static void DisplayData(System.Data.DataTable table)
             {
                 foreach (System.Data.DataRow row in table.Rows)
                 {
                     foreach (System.Data.DataColumn col in table.Columns)
                     {
                         Console.WriteLine("{0} = {1}", col.ColumnName, row[col]);
                     }
                     Console.WriteLine("============================");
                 }
             }

             static void Main(string[] args)
             {

                 string connStr = "server=localhost;user=root;database=world;port=3306;password=******;";
                 MySqlConnection conn = new MySqlConnection(connStr);

                 try
                 {
                     Console.WriteLine("Connecting to MySQL...");
                     conn.Open();

                     DataTable table = conn.GetSchema("MetaDataCollections");
                     //DataTable table = conn.GetSchema("UDF");
                     DisplayData(table);

                     conn.Close();
                 }
                 catch (Exception ex)
                 {
                     Console.WriteLine(ex.ToString());
                 }
                 Console.WriteLine("Done.");
             }
         }
     }

Further information on the `GetSchema()' method and schema collections
can be found in the Microsoft .NET documentation
(http://msdn.microsoft.com/en-us/library/kcax58fh(VS.80).aspx).


File: manual.info,  Node: connector-net-programming-mysqlcommand,  Next: connector-net-programming-connection-pooling,  Prev: connector-net-programming-connecting-connection-string,  Up: connector-net-programming

20.2.5.7 Using MySqlCommand
...........................

A MySqlCommand has the `CommandText' and `CommandType' properties
associated with it. The `CommandText' will be handled differently
depending on the setting of `CommandType'.  `CommandType' can be one of:

  1. Text - A SQL text command (default)

  2. StoredProcedure - The name of a Stored Procedure

  3. TableDirect - The name of a table (new in Connector/Net 6.2)

The default `CommandType', `Text', is used for executing queries and
other SQL commands. Some example of this can be found in the following
section *Note connector-net-tutorials-sql-command::.

If `CommandType' is set to `StoredProcedure', `CommandText' should be
set to the name of the Stored Procedure to access.

If `CommandType' is set to `TableDirect', all rows and columns of the
named table will be returned when you call one of the Execute methods.
In effect, this command performs a `SELECT *' on the table specified.
The `CommandText' property is set to the name of the table to query.
This is illustrated by the following code snippet:

     ...
     MySqlCommand cmd = new MySqlCommand();
     cmd.CommandText = "mytable";
     cmd.Connection = someConnection;
     cmd.CommandType = CommandType.TableDirect;
     MySqlDataReader reader = cmd.ExecuteReader();
     while (reader.Read())
     {
        Console.WriteLn(reader[0], reader[1]...);
     }
     ...

Examples of using the CommandType of StoredProcedure can be found in
the section *Note connector-net-programming-stored::.

Commands can have a timeout associated with them. This is useful as you
may not want a situation were a command takes up an excessive amount of
time. A timeout can be set using the `CommandTimeout' property. The
following code snippet sets a timeout of one minute:

     MySqlCommand cmd = new MySqlCommand();
     cmd.CommandTimeout = 60;

The default value is 30 secs. A value of 0 indicates an indefinite wait
and should be avoided. Note the default command timeout can be changed
using the connection string option `Default Command Timeout'.

Prior to MySQL Connector/Net 6.2, `MySqlCommand.CommandTimeout'
included user processing time, that is processing time not related to
direct use of the connector. Timeout was implemented through a .NET
Timer, that triggered after `CommandTimeout' seconds.  This timer
consumed a thread.

MySQL Connector/Net 6.2 introduced timeouts that are aligned with how
Microsoft handles `SqlCommand.CommandTimeout'. This property is the
cumulative timeout for all network reads and writes during command
execution or processing of the results. A timeout can still occur in
the `MySqlReader.Read' method after the first row is returned, and does
not include user processing time, only IO operations. The 6.2
implementation uses the underlying stream timeout facility, so is more
efficient in that it does not require the additional timer thread as
was the case with the previous implementation.

Further details on this can be found in the relevant Microsoft
documentation
(http://msdn.microsoft.com/en-us/library/system.data.sqlclient.sqlcommand.commandtimeout.aspx).


File: manual.info,  Node: connector-net-programming-connection-pooling,  Next: connector-net-programming-prepared,  Prev: connector-net-programming-mysqlcommand,  Up: connector-net-programming

20.2.5.8 Using Connector/Net with Connection Pooling
....................................................

The Connector/Net supports connection pooling. This is enabled by
default, but can be turned off using connection string options.  See
*Note connector-net-programming-connecting-connection-string:: for
further information.

Connection pooling works by keeping the native connection to the server
live when the client disposes of a `MySqlConnection'. Subsequently, if
a new `MySqlConnection' object is opened, it will be created from the
connection pool, rather than creating a new native connection. This
improves performance.

To work as designed, it is best to let the connection pooling system
manage all connections. You should not create a globally accessible
instance of `MySqlConnection' and then manually open and close it. This
interferes with the way the pooling works and can lead to unpredictable
results or even exceptions.

One approach that simplifies things is to avoid manually creating a
`MySqlConnection' object. Instead use the overloaded methods that take
a connection string as an argument.  Using this approach, Connector/Net
will automatically create, open, close and destroy connections, using
the connection pooling system for best performance.

Typed Datasets and the `MembershipProvider' and `RoleProvider' classes
use this approach. Most classes that have methods that take a
`MySqlConnection' as an argument, also have methods that take a
connection string as an argument. This includes `MySqlDataAdapter'.

Instead of manually creating `MySqlCommand' objects, you can use the
static methods of the `MySqlHelper' class. These take a connection
string as an argument, and they fully support connection pooling.

Starting with MySQL Connector/Net 6.2, there is a background job that
runs every three minutes and removes connections from pool that have
been idle (unused) for more than three minutes. The pool cleanup frees
resources on both client and server side. This is because on the client
side every connection uses a socket, and on the server side every
connection uses a socket and a thread.

Prior to this change, connections were never removed from the pool, and
the pool always contained the peak number of open connections. For
example, a web application that peaked at 1000 concurrent database
connections would consume 1000 threads and 1000 open sockets at the
server, without ever freeing up those resources from the connection
pool. Note, connections, no matter how old, will not be closed if the
number of connections in the pool is less than or equal to the value
set by the `Min Pool Size' connection string parameter.


File: manual.info,  Node: connector-net-programming-prepared,  Next: connector-net-programming-stored,  Prev: connector-net-programming-connection-pooling,  Up: connector-net-programming

20.2.5.9 Using the Connector/Net with Prepared Statements
.........................................................

* Menu:

* connector-net-programming-prepared-preparing::  Preparing Statements in Connector/Net

*Introduction*

As of MySQL 4.1, it is possible to use prepared statements with
Connector/Net. Use of prepared statements can provide significant
performance improvements on queries that are executed more than once.

Prepared execution is faster than direct execution for statements
executed more than once, primarily because the query is parsed only
once. In the case of direct execution, the query is parsed every time
it is executed. Prepared execution also can provide a reduction of
network traffic because for each execution of the prepared statement,
it is necessary only to send the data for the parameters.

Another advantage of prepared statements is that it uses a binary
protocol that makes data transfer between client and server more
efficient.


File: manual.info,  Node: connector-net-programming-prepared-preparing,  Prev: connector-net-programming-prepared,  Up: connector-net-programming-prepared

20.2.5.10 Preparing Statements in Connector/Net
...............................................

To prepare a statement, create a command object and set the
`.CommandText' property to your query.

After entering your statement, call the `.Prepare' method of the
`MySqlCommand' object. After the statement is prepared, add parameters
for each of the dynamic elements in the query.

After you enter your query and enter parameters, execute the statement
using the `.ExecuteNonQuery()', `.ExecuteScalar()', or `.ExecuteReader'
methods.

For subsequent executions, you need only modify the values of the
parameters and call the execute method again, there is no need to set
the `.CommandText' property or redefine the parameters.

Visual Basic Example

     Dim conn As New MySqlConnection
     Dim cmd As New MySqlCommand

     conn.ConnectionString = strConnection

     Try
        conn.Open()
        cmd.Connection = conn

        cmd.CommandText = "INSERT INTO myTable VALUES(NULL, @number, @text)"
        cmd.Prepare()

        cmd.Parameters.AddWithValue("@number", 1)
        cmd.Parameters.AddWithValue("@text", "One")

        For i = 1 To 1000
            cmd.Parameters("@number").Value = i
            cmd.Parameters("@text").Value = "A string value"

            cmd.ExecuteNonQuery()
          Next
     Catch ex As MySqlException
         MessageBox.Show("Error " & ex.Number & " has occurred: " & ex.Message, "Error", MessageBoxButtons.OK, MessageBoxIcon.Error)
     End Try

C# Example

     MySql.Data.MySqlClient.MySqlConnection conn;
     MySql.Data.MySqlClient.MySqlCommand cmd;

     conn = new MySql.Data.MySqlClient.MySqlConnection();
     cmd = new MySql.Data.MySqlClient.MySqlCommand();

     conn.ConnectionString = strConnection;

     try
     {
         conn.Open();
         cmd.Connection = conn;

         cmd.CommandText = "INSERT INTO myTable VALUES(NULL, @number, @text)";
         cmd.Prepare();

         cmd.Parameters.AddWithValue("@number", 1);
         cmd.Parameters.AddWithValue("@text", "One");

         for (int i=1; i <= 1000; i++)
         {
             cmd.Parameters["@number"].Value = i;
             cmd.Parameters["@text"].Value = "A string value";

             cmd.ExecuteNonQuery();
         }
     }
     catch (MySql.Data.MySqlClient.MySqlException ex)
     {
         MessageBox.Show("Error " + ex.Number + " has occurred: " + ex.Message,
             "Error", MessageBoxButtons.OK, MessageBoxIcon.Error);
     }


File: manual.info,  Node: connector-net-programming-stored,  Next: connector-net-programming-blob,  Prev: connector-net-programming-prepared,  Up: connector-net-programming

20.2.5.11 Accessing Stored Procedures with Connector/Net
........................................................

* Menu:

* connector-net-programming-stored-using::  Using Stored Routines from Connector/Net

*Introduction*

With the release of MySQL version 5 the MySQL server now supports
stored procedures with the SQL 2003 stored procedure syntax.

A stored procedure is a set of SQL statements that can be stored in the
server. Once this has been done, clients do not need to keep reissuing
the individual statements but can refer to the stored procedure instead.

Stored procedures can be particularly useful in situations such as the
following:

   * When multiple client applications are written in different
     languages or work on different platforms, but need to perform the
     same database operations.

   * When security is paramount. Banks, for example, use stored
     procedures for all common operations. This provides a consistent
     and secure environment, and procedures can ensure that each
     operation is properly logged. In such a setup, applications and
     users would not get any access to the database tables directly,
     but can only execute specific stored procedures.

Connector/Net supports the calling of stored procedures through the
`MySqlCommand' object. Data can be passed in and out of a MySQL stored
procedure through use of the `MySqlCommand.Parameters' collection.

*Note*:

When you call a stored procedure, the command object makes an
additional *Note `SELECT': select. call to determine the parameters of
the stored procedure. You must ensure that the user calling the
procedure has the `SELECT' privilege on the `mysql.proc' table to
enable them to verify the parameters. Failure to do this will result in
an error when calling the procedure.

This section will not provide in-depth information on creating Stored
Procedures. For such information, please refer to
`http://dev.mysql.com/doc/mysql/en/stored-routines.html'.

A sample application demonstrating how to use stored procedures with
Connector/Net can be found in the `Samples' directory of your
Connector/Net installation.


File: manual.info,  Node: connector-net-programming-stored-using,  Prev: connector-net-programming-stored,  Up: connector-net-programming-stored

20.2.5.12 Using Stored Routines from Connector/Net
..................................................

Stored procedures in MySQL can be created using a variety of tools.
First, stored procedures can be created using the *Note `mysql': mysql.
command-line client. Second, stored procedures can be created using
MySQL Workbench. Finally, stored procedures can be created using the
`.ExecuteNonQuery' method of the `MySqlCommand' object.

It should be noted that, unlike the command-line and GUI clients, you
are not required to specify a special delimiter when creating stored
procedures in Connector/Net.

To call a stored procedure using Connector/Net, you create a
`MySqlCommand' object and pass the stored procedure name as the
`.CommandText' property.  You then set the `.CommandType' property to
`CommandType.StoredProcedure'.

After the stored procedure is named, you create one `MySqlCommand'
parameter for every parameter in the stored procedure. `IN' parameters
are defined with the parameter name and the object containing the
value, `OUT' parameters are defined with the parameter name and the
data type that is expected to be returned. All parameters need the
parameter direction defined.

After defining the parameters, you call the stored procedure by using
the `MySqlCommand.ExecuteNonQuery()' method.

Once the stored procedure is called, the values of the output
parameters can be retrieved by using the `.Value' property of the
`MySqlConnector.Parameters' collection.

*Note*:

When a stored procedure is called using `MySqlCommand.ExecuteReader',
and the stored procedure has output parameters, the output parameters
are only set after the `MySqlDataReader' returned by `ExecuteReader' is
closed.

The following C# example code demonstrates the use of stored
procedures. It assumes the database 'employees' has already been
created:

     using System;
     using System.Collections.Generic;
     using System.Linq;
     using System.Text;

     using System.Data;
     using MySql.Data;
     using MySql.Data.MySqlClient;

     namespace UsingStoredRoutines
     {
         class Program
         {
             static void Main(string[] args)
             {
                 MySqlConnection conn = new MySqlConnection();
                 conn.ConnectionString = "server=localhost;user=root;database=employees;port=3306;password=******;";
                 MySqlCommand cmd = new MySqlCommand();

                 try
                 {
                     Console.WriteLine("Connecting to MySQL...");
                     conn.Open();
                     cmd.Connection = conn;
                     cmd.CommandText = "DROP PROCEDURE IF EXISTS add_emp";
                     cmd.ExecuteNonQuery();
                     cmd.CommandText = "DROP TABLE IF EXISTS emp";
                     cmd.ExecuteNonQuery();
                     cmd.CommandText = "CREATE TABLE emp (empno INT UNSIGNED NOT NULL AUTO_INCREMENT PRIMARY KEY, first_name VARCHAR(20), last_name VARCHAR(20), birthdate DATE)";
                     cmd.ExecuteNonQuery();

                     cmd.CommandText = "CREATE PROCEDURE add_emp(" +
                                       "IN fname VARCHAR(20), IN lname VARCHAR(20), IN bday DATETIME, OUT empno INT)" +
                                       "BEGIN INSERT INTO emp(first_name, last_name, birthdate) " +
                                       "VALUES(fname, lname, DATE(bday)); SET empno = LAST_INSERT_ID(); END";

                     cmd.ExecuteNonQuery();
                 }
                 catch (MySqlException ex)
                 {
                     Console.WriteLine ("Error " + ex.Number + " has occurred: " + ex.Message);
                 }
                 conn.Close();
                 Console.WriteLine("Connection closed.");
                 try
                 {
                     Console.WriteLine("Connecting to MySQL...");
                     conn.Open();
                     cmd.Connection = conn;

                     cmd.CommandText = "add_emp";
                     cmd.CommandType = CommandType.StoredProcedure;

                     cmd.Parameters.AddWithValue("@lname", "Jones");
                     cmd.Parameters["@lname"].Direction = ParameterDirection.Input;

                     cmd.Parameters.AddWithValue("@fname", "Tom");
                     cmd.Parameters["@fname"].Direction = ParameterDirection.Input;

                     cmd.Parameters.AddWithValue("@bday", "1940-06-07");
                     cmd.Parameters["@bday"].Direction = ParameterDirection.Input;

                     cmd.Parameters.AddWithValue("@empno", MySqlDbType.Int32);
                     cmd.Parameters["@empno"].Direction = ParameterDirection.Output;

                     cmd.ExecuteNonQuery();

                     Console.WriteLine("Employee number: "+cmd.Parameters["@empno"].Value);
                     Console.WriteLine("Birthday: " + cmd.Parameters["@bday"].Value);
                 }
                 catch (MySql.Data.MySqlClient.MySqlException ex)
                 {
                     Console.WriteLine("Error " + ex.Number + " has occurred: " + ex.Message);
                 }
                 conn.Close();
                 Console.WriteLine("Done.");
             }
         }
     }

The following code shows the same application in Visual Basic:


     Imports System
     Imports System.Collections.Generic
     Imports System.Linq
     Imports System.Text

     Imports System.Data
     Imports MySql.Data
     Imports MySql.Data.MySqlClient

     Module Module1

         Sub Main()
             Dim conn As New MySqlConnection()
             conn.ConnectionString = "server=localhost;user=root;database=world;port=3306;password=******;"
             Dim cmd As New MySqlCommand()

             Try
                 Console.WriteLine("Connecting to MySQL...")
                 conn.Open()
                 cmd.Connection = conn
                 cmd.CommandText = "DROP PROCEDURE IF EXISTS add_emp"
                 cmd.ExecuteNonQuery()
                 cmd.CommandText = "DROP TABLE IF EXISTS emp"
                 cmd.ExecuteNonQuery()
                 cmd.CommandText = "CREATE TABLE emp (empno INT UNSIGNED NOT NULL AUTO_INCREMENT PRIMARY KEY, first_name VARCHAR(20), last_name VARCHAR(20), birthdate DATE)"
                 cmd.ExecuteNonQuery()

                 cmd.CommandText = "CREATE PROCEDURE add_emp(" & "IN fname VARCHAR(20), IN lname VARCHAR(20), IN bday DATETIME, OUT empno INT)" & "BEGIN INSERT INTO emp(first_name, last_name, birthdate) " & "VALUES(fname, lname, DATE(bday)); SET empno = LAST_INSERT_ID(); END"

                 cmd.ExecuteNonQuery()
             Catch ex As MySqlException
                 Console.WriteLine(("Error " & ex.Number & " has occurred: ") + ex.Message)
             End Try
             conn.Close()
             Console.WriteLine("Connection closed.")
             Try
                 Console.WriteLine("Connecting to MySQL...")
                 conn.Open()
                 cmd.Connection = conn

                 cmd.CommandText = "add_emp"
                 cmd.CommandType = CommandType.StoredProcedure

                 cmd.Parameters.AddWithValue("@lname", "Jones")
                 cmd.Parameters("@lname").Direction = ParameterDirection.Input

                 cmd.Parameters.AddWithValue("@fname", "Tom")
                 cmd.Parameters("@fname").Direction = ParameterDirection.Input

                 cmd.Parameters.AddWithValue("@bday", "1940-06-07")
                 cmd.Parameters("@bday").Direction = ParameterDirection.Input

                 cmd.Parameters.AddWithValue("@empno", MySqlDbType.Int32)
                 cmd.Parameters("@empno").Direction = ParameterDirection.Output

                 cmd.ExecuteNonQuery()

                 Console.WriteLine("Employee number: " & cmd.Parameters("@empno").Value)
                 Console.WriteLine("Birthday: " & cmd.Parameters("@bday").Value)
             Catch ex As MySql.Data.MySqlClient.MySqlException
                 Console.WriteLine(("Error " & ex.Number & " has occurred: ") + ex.Message)
             End Try
             conn.Close()
             Console.WriteLine("Done.")

         End Sub

     End Module


File: manual.info,  Node: connector-net-programming-blob,  Next: connector-net-programming-crystal,  Prev: connector-net-programming-stored,  Up: connector-net-programming

20.2.5.13 Handling BLOB Data With Connector/Net
...............................................

* Menu:

* connector-net-programming-blob-serverprep::  Preparing the MySQL Server
* connector-net-programming-blob-writing::  Writing a File to the Database
* connector-net-programming-blob-reading::  Reading a BLOB from the Database to a File on Disk

*Introduction*

One common use for MySQL is the storage of binary data in *Note `BLOB':
blob. columns. MySQL supports four different BLOB data types: *Note
`TINYBLOB': blob, *Note `BLOB': blob, *Note `MEDIUMBLOB': blob, and
*Note `LONGBLOB': blob.

Data stored in a BLOB column can be accessed using Connector/Net and
manipulated using client-side code. There are no special requirements
for using Connector/Net with BLOB data.

Simple code examples will be presented within this section, and a full
sample application can be found in the `Samples' directory of the
Connector/Net installation.


File: manual.info,  Node: connector-net-programming-blob-serverprep,  Next: connector-net-programming-blob-writing,  Prev: connector-net-programming-blob,  Up: connector-net-programming-blob

20.2.5.14 Preparing the MySQL Server
....................................

The first step is using MySQL with BLOB data is to configure the
server. Let's start by creating a table to be accessed. In my file
tables, I usually have four columns: an AUTO_INCREMENT column of
appropriate size (UNSIGNED SMALLINT) to serve as a primary key to
identify the file, a VARCHAR column that stores the file name, an
UNSIGNED MEDIUMINT column that stores the size of the file, and a
MEDIUMBLOB column that stores the file itself. For this example, I will
use the following table definition:

     CREATE TABLE file(
     file_id SMALLINT UNSIGNED AUTO_INCREMENT NOT NULL PRIMARY KEY,
     file_name VARCHAR(64) NOT NULL,
     file_size MEDIUMINT UNSIGNED NOT NULL,
     file MEDIUMBLOB NOT NULL);

After creating a table, you might need to modify the
`max_allowed_packet' system variable. This variable determines how
large of a packet (that is, a single row) can be sent to the MySQL
server. By default, the server only accepts a maximum size of 1MB from
the client application.  If you do not intend to exceed 1MB, this
should be fine. If you do intend to exceed 1MB in your file transfers,
increase this number.

The `max_allowed_packet' option can be modified using MySQL
Administrator's Startup Variables screen. Adjust the Maximum permitted
option in the Memory section of the Networking tab to an appropriate
setting. After adjusting the value, click the `Apply Changes' button
and restart the server using the `Service Control' screen of MySQL
Administrator. You can also adjust this value directly in the my.cnf
file (add a line that reads max_allowed_packet=xxM), or use the SET
max_allowed_packet=xxM; syntax from within MySQL.

Try to be conservative when setting `max_allowed_packet', as transfers
of BLOB data can take some time to complete. Try to set a value that
will be adequate for your intended use and increase the value if
necessary.


File: manual.info,  Node: connector-net-programming-blob-writing,  Next: connector-net-programming-blob-reading,  Prev: connector-net-programming-blob-serverprep,  Up: connector-net-programming-blob

20.2.5.15 Writing a File to the Database
........................................

To write a file to a database, we need to convert the file to a byte
array, then use the byte array as a parameter to an *Note `INSERT':
insert. query.

The following code opens a file using a FileStream object, reads it
into a byte array, and inserts it into the `file' table:

Visual Basic Example

     Dim conn As New MySqlConnection
     Dim cmd As New MySqlCommand

     Dim SQL As String

     Dim FileSize As UInt32
     Dim rawData() As Byte
     Dim fs As FileStream

     conn.ConnectionString = "server=127.0.0.1;" _
         & "uid=root;" _
         & "pwd=12345;" _
         & "database=test"

     Try
         fs = New FileStream("c:\image.png", FileMode.Open, FileAccess.Read)
         FileSize = fs.Length

         rawData = New Byte(FileSize) {}
         fs.Read(rawData, 0, FileSize)
         fs.Close()

         conn.Open()

         SQL = "INSERT INTO file VALUES(NULL, @FileName, @FileSize, @File)"

         cmd.Connection = conn
         cmd.CommandText = SQL
         cmd.Parameters.AddWithValue("@FileName", strFileName)
         cmd.Parameters.AddWithValue("@FileSize", FileSize)
         cmd.Parameters.AddWithValue("@File", rawData)

         cmd.ExecuteNonQuery()

         MessageBox.Show("File Inserted into database successfully!", _
         "Success!", MessageBoxButtons.OK, MessageBoxIcon.Asterisk)

         conn.Close()
     Catch ex As Exception
         MessageBox.Show("There was an error: " & ex.Message, "Error", _
             MessageBoxButtons.OK, MessageBoxIcon.Error)
     End Try

C# Example

     MySql.Data.MySqlClient.MySqlConnection conn;
     MySql.Data.MySqlClient.MySqlCommand cmd;

     conn = new MySql.Data.MySqlClient.MySqlConnection();
     cmd = new MySql.Data.MySqlClient.MySqlCommand();

     string SQL;
     UInt32 FileSize;
     byte[] rawData;
     FileStream fs;

     conn.ConnectionString = "server=127.0.0.1;uid=root;" +
         "pwd=12345;database=test;";

     try
     {
         fs = new FileStream(@"c:\image.png", FileMode.Open, FileAccess.Read);
         FileSize = fs.Length;

         rawData = new byte[FileSize];
         fs.Read(rawData, 0, FileSize);
         fs.Close();

         conn.Open();

         SQL = "INSERT INTO file VALUES(NULL, @FileName, @FileSize, @File)";

         cmd.Connection = conn;
         cmd.CommandText = SQL;
         cmd.Parameters.AddWithValue("@FileName", strFileName);
         cmd.Parameters.AddWithValue("@FileSize", FileSize);
         cmd.Parameters.AddWithValue("@File", rawData);

         cmd.ExecuteNonQuery();

         MessageBox.Show("File Inserted into database successfully!",
             "Success!", MessageBoxButtons.OK, MessageBoxIcon.Asterisk);

         conn.Close();
     }
     catch (MySql.Data.MySqlClient.MySqlException ex)
     {
         MessageBox.Show("Error " + ex.Number + " has occurred: " + ex.Message,
             "Error", MessageBoxButtons.OK, MessageBoxIcon.Error);
     }

The `Read' method of the `FileStream' object is used to load the file
into a byte array which is sized according to the `Length' property of
the FileStream object.

After assigning the byte array as a parameter of the `MySqlCommand'
object, the `ExecuteNonQuery' method is called and the BLOB is inserted
into the `file' table.


File: manual.info,  Node: connector-net-programming-blob-reading,  Prev: connector-net-programming-blob-writing,  Up: connector-net-programming-blob

20.2.5.16 Reading a BLOB from the Database to a File on Disk
............................................................

Once a file is loaded into the `file' table, we can use the
`MySqlDataReader' class to retrieve it.

The following code retrieves a row from the `file' table, then loads
the data into a `FileStream' object to be written to disk:

Visual Basic Example

     Dim conn As New MySqlConnection
     Dim cmd As New MySqlCommand
     Dim myData As MySqlDataReader
     Dim SQL As String
     Dim rawData() As Byte
     Dim FileSize As UInt32
     Dim fs As FileStream

     conn.ConnectionString = "server=127.0.0.1;" _
         & "uid=root;" _
         & "pwd=12345;" _
         & "database=test"

     SQL = "SELECT file_name, file_size, file FROM file"

     Try
         conn.Open()

         cmd.Connection = conn
         cmd.CommandText = SQL

         myData = cmd.ExecuteReader

         If Not myData.HasRows Then Throw New Exception("There are no BLOBs to save")

         myData.Read()

         FileSize = myData.GetUInt32(myData.GetOrdinal("file_size"))
         rawData = New Byte(FileSize) {}

         myData.GetBytes(myData.GetOrdinal("file"), 0, rawData, 0, FileSize)

         fs = New FileStream("C:\newfile.png", FileMode.OpenOrCreate, FileAccess.Write)
         fs.Write(rawData, 0, FileSize)
         fs.Close()

         MessageBox.Show("File successfully written to disk!", "Success!", MessageBoxButtons.OK, MessageBoxIcon.Asterisk)

         myData.Close()
         conn.Close()
     Catch ex As Exception
         MessageBox.Show("There was an error: " & ex.Message, "Error", MessageBoxButtons.OK, MessageBoxIcon.Error)
     End Try

C# Example

     MySql.Data.MySqlClient.MySqlConnection conn;
     MySql.Data.MySqlClient.MySqlCommand cmd;
     MySql.Data.MySqlClient.MySqlDataReader myData;

     conn = new MySql.Data.MySqlClient.MySqlConnection();
     cmd = new MySql.Data.MySqlClient.MySqlCommand();

     string SQL;
     UInt32 FileSize;
     byte[] rawData;
     FileStream fs;

     conn.ConnectionString = "server=127.0.0.1;uid=root;" +
         "pwd=12345;database=test;";

     SQL = "SELECT file_name, file_size, file FROM file";

     try
     {
         conn.Open();

         cmd.Connection = conn;
         cmd.CommandText = SQL;

         myData = cmd.ExecuteReader();

         if (! myData.HasRows)
             throw new Exception("There are no BLOBs to save");

         myData.Read();

         FileSize = myData.GetUInt32(myData.GetOrdinal("file_size"));
         rawData = new byte[FileSize];

         myData.GetBytes(myData.GetOrdinal("file"), 0, rawData, 0, FileSize);

         fs = new FileStream(@"C:\newfile.png", FileMode.OpenOrCreate, FileAccess.Write);
         fs.Write(rawData, 0, FileSize);
         fs.Close();

         MessageBox.Show("File successfully written to disk!",
             "Success!", MessageBoxButtons.OK, MessageBoxIcon.Asterisk);

         myData.Close();
         conn.Close();
     }
     catch (MySql.Data.MySqlClient.MySqlException ex)
     {
         MessageBox.Show("Error " + ex.Number + " has occurred: " + ex.Message,
             "Error", MessageBoxButtons.OK, MessageBoxIcon.Error);
     }

After connecting, the contents of the `file' table are loaded into a
`MySqlDataReader' object. The `GetBytes' method of the MySqlDataReader
is used to load the BLOB into a byte array, which is then written to
disk using a FileStream object.

The `GetOrdinal' method of the MySqlDataReader can be used to determine
the integer index of a named column.  Use of the GetOrdinal method
prevents errors if the column order of the *Note `SELECT': select.
query is changed.


File: manual.info,  Node: connector-net-programming-crystal,  Next: connector-net-programming-datetime,  Prev: connector-net-programming-blob,  Up: connector-net-programming

20.2.5.17 Using Connector/Net with Crystal Reports
..................................................

* Menu:

* connector-net-programming-crystal-source::  Creating a Data Source
* connector-net-programming-crystal-creating::  Creating the Report
* connector-net-programming-crystal-displaying::  Displaying the Report

*Introduction*

Crystal Reports is a common tool used by Windows application developers
to perform reporting and document generation. In this section we will
show how to use Crystal Reports XI with MySQL and Connector/Net.


File: manual.info,  Node: connector-net-programming-crystal-source,  Next: connector-net-programming-crystal-creating,  Prev: connector-net-programming-crystal,  Up: connector-net-programming-crystal

20.2.5.18 Creating a Data Source
................................

When creating a report in Crystal Reports there are two options for
accessing the MySQL data while designing your report.

The first option is to use Connector/ODBC as an ADO data source when
designing your report. You will be able to browse your database and
choose tables and fields using drag and drop to build your report. The
disadvantage of this approach is that additional work must be performed
within your application to produce a data set that matches the one
expected by your report.

The second option is to create a data set in VB.NET and save it as XML.
This XML file can then be used to design a report. This works quite
well when displaying the report in your application, but is less
versatile at design time because you must choose all relevant columns
when creating the data set. If you forget a column you must re-create
the data set before the column can be added to the report.

The following code can be used to create a data set from a query and
write it to disk:

Visual Basic Example

     Dim myData As New DataSet
     Dim conn As New MySqlConnection
     Dim cmd As New MySqlCommand
     Dim myAdapter As New MySqlDataAdapter

     conn.ConnectionString = "server=127.0.0.1;" _
         & "uid=root;" _
         & "pwd=12345;" _
         & "database=world"

     Try
         conn.Open()
         cmd.CommandText = "SELECT city.name AS cityName, city.population AS CityPopulation, " _
             & "country.name, country.population, country.continent " _
             & "FROM country, city ORDER BY country.continent, country.name"
         cmd.Connection = conn

         myAdapter.SelectCommand = cmd
         myAdapter.Fill(myData)

         myData.WriteXml("C:\dataset.xml", XmlWriteMode.WriteSchema)
     Catch ex As Exception
         MessageBox.Show(ex.Message, "Report could not be created", MessageBoxButtons.OK, MessageBoxIcon.Error)
     End Try

C# Example

     DataSet myData = new DataSet();
     MySql.Data.MySqlClient.MySqlConnection conn;
     MySql.Data.MySqlClient.MySqlCommand cmd;
     MySql.Data.MySqlClient.MySqlDataAdapter myAdapter;

     conn = new MySql.Data.MySqlClient.MySqlConnection();
     cmd = new MySql.Data.MySqlClient.MySqlCommand();
     myAdapter = new MySql.Data.MySqlClient.MySqlDataAdapter();

     conn.ConnectionString = "server=127.0.0.1;uid=root;" +
       "pwd=12345;database=test;";

     try
     {
       cmd.CommandText = "SELECT city.name AS cityName, city.population AS CityPopulation, " +
       "country.name, country.population, country.continent " +
       "FROM country, city ORDER BY country.continent, country.name";
       cmd.Connection = conn;

       myAdapter.SelectCommand = cmd;
       myAdapter.Fill(myData);

       myData.WriteXml(@"C:\dataset.xml", XmlWriteMode.WriteSchema);
     }
     catch (MySql.Data.MySqlClient.MySqlException ex)
     {
       MessageBox.Show(ex.Message, "Report could not be created",
       MessageBoxButtons.OK, MessageBoxIcon.Error);
     }

The resulting XML file can be used as an ADO.NET XML datasource when
designing your report.

If you choose to design your reports using Connector/ODBC, it can be
downloaded from dev.mysql.com
(http://dev.mysql.com/downloads/connector/odbc/3.51.html).


File: manual.info,  Node: connector-net-programming-crystal-creating,  Next: connector-net-programming-crystal-displaying,  Prev: connector-net-programming-crystal-source,  Up: connector-net-programming-crystal

20.2.5.19 Creating the Report
.............................

For most purposes the Standard Report wizard should help with the
initial creation of a report. To start the wizard, open Crystal Reports
and choose the New > Standard Report option from the File menu.

The wizard will first prompt you for a data source. If you are using
Connector/ODBC as your data source, use the OLEDB provider for ODBC
option from the OLE DB (ADO) tree instead of the ODBC (RDO) tree when
choosing a data source. If using a saved data set, choose the ADO.NET
(XML) option and browse to your saved data set.

The remainder of the report creation process is done automatically by
the wizard.

After the report is created, choose the Report Options... entry of the
File menu. Un-check the Save Data With Report option.  This prevents
saved data from interfering with the loading of data within our
application.


File: manual.info,  Node: connector-net-programming-crystal-displaying,  Prev: connector-net-programming-crystal-creating,  Up: connector-net-programming-crystal

20.2.5.20 Displaying the Report
...............................

To display a report we first populate a data set with the data needed
for the report, then load the report and bind it to the data set.
Finally we pass the report to the crViewer control for display to the
user.

The following references are needed in a project that displays a report:

   * CrystalDecisions.CrystalReports.Engine

   * CrystalDecisions.ReportSource

   * CrystalDecisions.Shared

   * CrystalDecisions.Windows.Forms

The following code assumes that you created your report using a data
set saved using the code shown in *Note
connector-net-programming-crystal-source::, and have a crViewer control
on your form named `myViewer'.

Visual Basic Example

     Imports CrystalDecisions.CrystalReports.Engine
     Imports System.Data
     Imports MySql.Data.MySqlClient

     Dim myReport As New ReportDocument
     Dim myData As New DataSet
     Dim conn As New MySqlConnection
     Dim cmd As New MySqlCommand
     Dim myAdapter As New MySqlDataAdapter

     conn.ConnectionString = _
         "server=127.0.0.1;" _
         & "uid=root;" _
         & "pwd=12345;" _
         & "database=test"

     Try
         conn.Open()

         cmd.CommandText = "SELECT city.name AS cityName, city.population AS CityPopulation, " _
             & "country.name, country.population, country.continent " _
             & "FROM country, city ORDER BY country.continent, country.name"
         cmd.Connection = conn

         myAdapter.SelectCommand = cmd
         myAdapter.Fill(myData)

         myReport.Load(".\world_report.rpt")
         myReport.SetDataSource(myData)
         myViewer.ReportSource = myReport
     Catch ex As Exception
         MessageBox.Show(ex.Message, "Report could not be created", MessageBoxButtons.OK, MessageBoxIcon.Error)
     End Try

C# Example

     using CrystalDecisions.CrystalReports.Engine;
     using System.Data;
     using MySql.Data.MySqlClient;

     ReportDocument myReport = new ReportDocument();
     DataSet myData = new DataSet();
     MySql.Data.MySqlClient.MySqlConnection conn;
     MySql.Data.MySqlClient.MySqlCommand cmd;
     MySql.Data.MySqlClient.MySqlDataAdapter myAdapter;

     conn = new MySql.Data.MySqlClient.MySqlConnection();
     cmd = new MySql.Data.MySqlClient.MySqlCommand();
     myAdapter = new MySql.Data.MySqlClient.MySqlDataAdapter();

     conn.ConnectionString = "server=127.0.0.1;uid=root;" +
         "pwd=12345;database=test;";

     try
     {
         cmd.CommandText = "SELECT city.name AS cityName, city.population AS CityPopulation, " +
             "country.name, country.population, country.continent " +
             "FROM country, city ORDER BY country.continent, country.name";
         cmd.Connection = conn;

         myAdapter.SelectCommand = cmd;
         myAdapter.Fill(myData);

         myReport.Load(@".\world_report.rpt");
         myReport.SetDataSource(myData);
         myViewer.ReportSource = myReport;
     }
     catch (MySql.Data.MySqlClient.MySqlException ex)
     {
         MessageBox.Show(ex.Message, "Report could not be created",
             MessageBoxButtons.OK, MessageBoxIcon.Error);
     }

A new data set it generated using the same query used to generate the
previously saved data set. Once the data set is filled, a
ReportDocument is used to load the report file and bind it to the data
set. The ReportDocument is the passed as the ReportSource of the
crViewer.

This same approach is taken when a report is created from a single
table using Connector/ODBC. The data set replaces the table used in the
report and the report is displayed properly.

When a report is created from multiple tables using Connector/ODBC, a
data set with multiple tables must be created in our application. This
enables each table in the report data source to be replaced with a
report in the data set.

We populate a data set with multiple tables by providing multiple *Note
`SELECT': select. statements in our MySqlCommand object. These *Note
`SELECT': select.  statements are based on the SQL query shown in
Crystal Reports in the Database menu's Show SQL Query option. Assume the
following query:

     SELECT `country`.`Name`, `country`.`Continent`, `country`.`Population`, `city`.`Name`, `city`.`Population`
     FROM `world`.`country` `country` LEFT OUTER JOIN `world`.`city` `city` ON `country`.`Code`=`city`.`CountryCode`
     ORDER BY `country`.`Continent`, `country`.`Name`, `city`.`Name`

This query is converted to two *Note `SELECT': select. queries and
displayed with the following code:

Visual Basic Example

     Imports CrystalDecisions.CrystalReports.Engine
     Imports System.Data
     Imports MySql.Data.MySqlClient

     Dim myReport As New ReportDocument
     Dim myData As New DataSet
     Dim conn As New MySqlConnection
     Dim cmd As New MySqlCommand
     Dim myAdapter As New MySqlDataAdapter

     conn.ConnectionString = "server=127.0.0.1;" _
         & "uid=root;" _
         & "pwd=12345;" _
         & "database=world"

     Try
         conn.Open()
         cmd.CommandText = "SELECT name, population, countrycode FROM city ORDER BY countrycode, name; " _
             & "SELECT name, population, code, continent FROM country ORDER BY continent, name"
         cmd.Connection = conn

         myAdapter.SelectCommand = cmd
         myAdapter.Fill(myData)

         myReport.Load(".\world_report.rpt")
         myReport.Database.Tables(0).SetDataSource(myData.Tables(0))
         myReport.Database.Tables(1).SetDataSource(myData.Tables(1))
         myViewer.ReportSource = myReport
     Catch ex As Exception
         MessageBox.Show(ex.Message, "Report could not be created", MessageBoxButtons.OK, MessageBoxIcon.Error)
     End Try

C# Example

     using CrystalDecisions.CrystalReports.Engine;
     using System.Data;
     using MySql.Data.MySqlClient;

     ReportDocument myReport = new ReportDocument();
     DataSet myData = new DataSet();
     MySql.Data.MySqlClient.MySqlConnection conn;
     MySql.Data.MySqlClient.MySqlCommand cmd;
     MySql.Data.MySqlClient.MySqlDataAdapter myAdapter;

     conn = new MySql.Data.MySqlClient.MySqlConnection();
     cmd = new MySql.Data.MySqlClient.MySqlCommand();
     myAdapter = new MySql.Data.MySqlClient.MySqlDataAdapter();

     conn.ConnectionString = "server=127.0.0.1;uid=root;" +
         "pwd=12345;database=test;";

     try
     {
         cmd.CommandText = "SELECT name, population, countrycode FROM city ORDER " +
             "BY countrycode, name; *Note `SELECT': select. name, population, code, continent FROM " +
             "country ORDER BY continent, name";
         cmd.Connection = conn;

         myAdapter.SelectCommand = cmd;
         myAdapter.Fill(myData);

         myReport.Load(@".\world_report.rpt");
         myReport.Database.Tables(0).SetDataSource(myData.Tables(0));
         myReport.Database.Tables(1).SetDataSource(myData.Tables(1));
         myViewer.ReportSource = myReport;
     }
     catch (MySql.Data.MySqlClient.MySqlException ex)
     {
         MessageBox.Show(ex.Message, "Report could not be created",
             MessageBoxButtons.OK, MessageBoxIcon.Error);
     }

It is important to order the *Note `SELECT': select. queries in
alphabetic order, as this is the order the report will expect its source
tables to be in. One SetDataSource statement is needed for each table
in the report.

This approach can cause performance problems because Crystal Reports
must bind the tables together on the client-side, which will be slower
than using a pre-saved data set.


File: manual.info,  Node: connector-net-programming-datetime,  Next: connector-net-programming-asp-provider,  Prev: connector-net-programming-crystal,  Up: connector-net-programming

20.2.5.21 Handling Date and Time Information in Connector/Net
.............................................................

* Menu:

* connector-net-programming-datetime-problems::  Problems when Using Invalid Dates
* connector-net-programming-datetime-restricting::  Restricting Invalid Dates
* connector-net-programming-datetime-invalid::  Handling Invalid Dates
* connector-net-programming-datetime-null::  Handling NULL Dates

*Introduction*

MySQL and the .NET languages handle date and time information
differently, with MySQL allowing dates that cannot be represented by a
.NET data type, such as '`0000-00-00 00:00:00''. These differences can
cause problems if not properly handled.

In this section we will demonstrate how to properly handle date and
time information when using Connector/Net.


File: manual.info,  Node: connector-net-programming-datetime-problems,  Next: connector-net-programming-datetime-restricting,  Prev: connector-net-programming-datetime,  Up: connector-net-programming-datetime

20.2.5.22 Problems when Using Invalid Dates
...........................................

The differences in date handling can cause problems for developers who
use invalid dates. Invalid MySQL dates cannot be loaded into native
.NET `DateTime' objects, including `NULL' dates.

Because of this issue, .NET `DataSet' objects cannot be populated by
the `Fill' method of the `MySqlDataAdapter' class as invalid dates will
cause a `System.ArgumentOutOfRangeException' exception to occur.


File: manual.info,  Node: connector-net-programming-datetime-restricting,  Next: connector-net-programming-datetime-invalid,  Prev: connector-net-programming-datetime-problems,  Up: connector-net-programming-datetime

20.2.5.23 Restricting Invalid Dates
...................................

The best solution to the date problem is to restrict users from
entering invalid dates. This can be done on either the client or the
server side.

Restricting invalid dates on the client side is as simple as always
using the .NET `DateTime' class to handle dates. The `DateTime' class
will only allow valid dates, ensuring that the values in your database
are also valid. The disadvantage of this is that it is not useful in a
mixed environment where .NET and non .NET code are used to manipulate
the database, as each application must perform its own date validation.

Users of MySQL 5.0.2 and higher can use the new `traditional' SQL mode
to restrict invalid date values. For information on using the
`traditional' SQL mode, see *Note server-sql-mode::.


File: manual.info,  Node: connector-net-programming-datetime-invalid,  Next: connector-net-programming-datetime-null,  Prev: connector-net-programming-datetime-restricting,  Up: connector-net-programming-datetime

20.2.5.24 Handling Invalid Dates
................................

Although it is strongly recommended that you avoid the use of invalid
dates within your .NET application, it is possible to use invalid dates
by means of the `MySqlDateTime' data type.

The `MySqlDateTime' data type supports the same date values that are
supported by the MySQL server. The default behavior of Connector/Net is
to return a .NET DateTime object for valid date values, and return an
error for invalid dates.  This default can be modified to cause
Connector/Net to return `MySqlDateTime' objects for invalid dates.

To instruct Connector/Net to return a `MySqlDateTime' object for
invalid dates, add the following line to your connection string:

     Allow Zero Datetime=True

Please note that the use of the `MySqlDateTime' class can still be
problematic. The following are some known issues:

  1. Data binding for invalid dates can still cause errors (zero dates
     like 0000-00-00 do not seem to have this problem).

  2. The `ToString' method return a date formatted in the standard
     MySQL format (for example, `2005-02-23 08:50:25'). This differs
     from the `ToString' behavior of the .NET DateTime class.

  3. The `MySqlDateTime' class supports NULL dates, while the .NET
     DateTime class does not. This can cause errors when trying to
     convert a MySQLDateTime to a DateTime if you do not check for NULL
     first.

Because of the known issues, the best recommendation is still to use
only valid dates in your application.


File: manual.info,  Node: connector-net-programming-datetime-null,  Prev: connector-net-programming-datetime-invalid,  Up: connector-net-programming-datetime

20.2.5.25 Handling NULL Dates
.............................

The .NET `DateTime' data type cannot handle `NULL' values. As such,
when assigning values from a query to a `DateTime' variable, you must
first check whether the value is in fact `NULL'.

When using a `MySqlDataReader', use the `.IsDBNull' method to check
whether a value is `NULL' before making the assignment:

Visual Basic Example

     If Not myReader.IsDBNull(myReader.GetOrdinal("mytime")) Then
         myTime = myReader.GetDateTime(myReader.GetOrdinal("mytime"))
     Else
         myTime = DateTime.MinValue
     End If

C# Example

     if (! myReader.IsDBNull(myReader.GetOrdinal("mytime")))
         myTime = myReader.GetDateTime(myReader.GetOrdinal("mytime"));
     else
         myTime = DateTime.MinValue;

`NULL' values will work in a data set and can be bound to form controls
without special handling.


File: manual.info,  Node: connector-net-programming-asp-provider,  Next: connector-net-programming-binary-issues,  Prev: connector-net-programming-datetime,  Up: connector-net-programming

20.2.5.26 ASP.NET Provider Model
................................

MySQL Connector/Net provides support for the ASP.NET 2.0 provider
model. This model enables application developers to focus on the
business logic of their application instead of having to recreate such
boilerplate items as membership and roles support.

MySQL Connector/Net supplies the following providers:

   * Membership Provider

   * Role Provider

   * Profile Provider

   * Session State Provider (MySQL Connector/Net 6.1 and later)

The following tables show the supported providers, their default
provider and the corresponding MySQL provider.

*Membership Provider*

Default Provider                     MySQL Provider
System.Web.Security.SqlMembershipProviderMySql.Web.Security.MySQLMembershipProvider

*Role Provider*

Default Provider                     MySQL Provider
System.Web.Security.SqlRoleProvider  MySql.Web.Security.MySQLRoleProvider

*Profile Provider*

Default Provider                     MySQL Provider
System.Web.Profile.SqlProfileProviderMySql.Web.Profile.MySQLProfileProvider

*SessionState Provider*

Default Provider                     MySQL Provider
System.Web.SessionState.InProcSessionStateStoreMySql.Web.SessionState.MySqlSessionStateStore

*Note*:

The MySQL Session State provider uses slightly different capitalization
on the class name compared to the other MySQL providers.

*Installing The Providers*

The installation of Connector/Net 5.1 or later will install the
providers and register them in your machine's .NET configuration file,
`machine.config'. The additional entries created will result in the
`system.web' section appearing similar to the following code:

     <system.web>
       <processModel autoConfig="true" />
       <httpHandlers />
       <membership>
         <providers>
           <add name="AspNetSqlMembershipProvider" type="System.Web.Security.SqlMembershipProvider, System.Web, Version=2.0.0.0, Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a" connectionStringName="LocalSqlServer" enablePasswordRetrieval="false" enablePasswordReset="true" requiresQuestionAndAnswer="true" applicationName="/" requiresUniqueEmail="false" passwordFormat="Hashed" maxInvalidPasswordAttempts="5" minRequiredPasswordLength="7" minRequiredNonalphanumericCharacters="1" passwordAttemptWindow="10" passwordStrengthRegularExpression="" />
           <add name="MySQLMembershipProvider" type="MySql.Web.Security.MySQLMembershipProvider, MySql.Web, Version=6.1.1.0, Culture=neutral, PublicKeyToken=c5687fc88969c44d" connectionStringName="LocalMySqlServer" enablePasswordRetrieval="false" enablePasswordReset="true" requiresQuestionAndAnswer="true" applicationName="/" requiresUniqueEmail="false" passwordFormat="Clear" maxInvalidPasswordAttempts="5" minRequiredPasswordLength="7" minRequiredNonalphanumericCharacters="1" passwordAttemptWindow="10" passwordStrengthRegularExpression="" />
         </providers>
       </membership>
       <profile>
         <providers>
           <add name="AspNetSqlProfileProvider" connectionStringName="LocalSqlServer" applicationName="/" type="System.Web.Profile.SqlProfileProvider, System.Web, Version=2.0.0.0, Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a" />
           <add name="MySQLProfileProvider" type="MySql.Web.Profile.MySQLProfileProvider, MySql.Web, Version=6.1.1.0, Culture=neutral, PublicKeyToken=c5687fc88969c44d" connectionStringName="LocalMySqlServer" applicationName="/" />
         </providers>
       </profile>
       <roleManager>
         <providers>
           <add name="AspNetSqlRoleProvider" connectionStringName="LocalSqlServer" applicationName="/" type="System.Web.Security.SqlRoleProvider, System.Web, Version=2.0.0.0, Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a" />
           <add name="AspNetWindowsTokenRoleProvider" applicationName="/" type="System.Web.Security.WindowsTokenRoleProvider, System.Web, Version=2.0.0.0, Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a" />
           <add name="MySQLRoleProvider" type="MySql.Web.Security.MySQLRoleProvider, MySql.Web, Version=6.1.1.0, Culture=neutral, PublicKeyToken=c5687fc88969c44d" connectionStringName="LocalMySqlServer" applicationName="/" />
         </providers>
       </roleManager>
     </system.web>

Each provider type can have multiple provider implementations. The
default provider can also be set here using the `defaultProvider'
attribute, but usually this is set in the `web.config' file either
manually or by using the ASP.NET configuration tool.

At time of writing, the `MySqlSessionStateStore' is not added to
`machine.config' at install time, and so add the following:

     <sessionState>
       <providers>
         <add name="MySqlSessionStateStore" type="MySql.Web.SessionState.MySqlSessionStateStore, MySql.Web, Version=6.1.1.0, Culture=neutral, PublicKeyToken=c5687fc88969c44d" connectionStringName="LocalMySqlServer" applicationName="/" />
       </providers>
     </sessionState>

The SessionState Provider uses the `customProvider' attribute, rather
than `defaultProvider', to set the provider as the default. A typical
`web.config' file might contain:

        <system.web>
             <membership defaultProvider="MySQLMembershipProvider" />
             <roleManager defaultProvider="MySQLRoleProvider" />
             <profile defaultProvider="MySQLProfileProvider" />
             <sessionState customProvider="MySqlSessionStateStore" />
             <compilation debug="false">
               ...

This sets the MySQL Providers as the defaults to be used in this web
application.

The providers are implemented in the file `mysql.web.dll' and this file
can be found in your MySQL Connector/Net installation folder. There is
no need to run any type of SQL script to set up the database schema, as
the providers create and maintain the proper schema automatically.

* Using The Providers*

The easiest way to start using the providers is to use the ASP.NET
configuration tool that is available on the Solution Explorer toolbar
when you have a website project loaded.

In the web pages that open, you can select the MySQL membership and
roles providers by picking a custom provider for each area.

When the provider is installed, it creates a dummy connection string
named `LocalMySqlServer'. Although this has to be done so that the
provider will work in the ASP.NET configuration tool, you override this
connection string in your `web.config' file. You do this by first
removing the dummy connection string and then adding in the proper one,
as shown in the following example:

     <connectionStrings>
       <remove name="LocalMySqlServer"/>
       <add name="LocalMySqlServer" connectionString="server=xxx;uid=xxx;pwd=xxx;database=xxx;"/>
     </connectionStrings>

Note the database to connect to must be specified.

Rather than manually editing configuration files, consider using the
MySQL Website Configuration tool to configure your desired provider
setup. From MySQL Connector/Net 6.1.1 onwards, all providers can be
selected and configured from this wizard. The tool modifies your
`website.config' file to the desired configuration. A tutorial on doing
this is available in the following section *Note
connector-net-website-config::.

A tutorial demonstrating how to use the Membership and Role Providers
can be found in the following section *Note
connector-net-tutorials-asp-roles::.

* Deployment*

To use the providers on a production server, distribute the
`MySql.Data' and the `MySql.Web' assemblies, and either register them
in the remote systems Global Assembly Cache or keep them in your
application's `bin/' directory.


File: manual.info,  Node: connector-net-programming-binary-issues,  Next: connector-net-using-character-sets,  Prev: connector-net-programming-asp-provider,  Up: connector-net-programming

20.2.5.27 Binary/Nonbinary Issues
.................................

There are certain situations where MySQL will return incorrect metadata
about one or more columns. More specifically, the server will sometimes
report that a column is binary when it is not and vice versa. In these
situations, it becomes practically impossible for the connector to be
able to correctly identify the correct metadat.

Some examples of situations that may return incorrect metadata are:

   * Execution of *Note `SHOW PROCESSLIST': show-processlist.  Some of
     the columns will be returned as binary even though they only hold
     string data.

   * When a temp table is used to process a resultset, some columns may
     be returned with incorrect binary flags.

   * Some server functions such `DATE_FORMAT' will incorrectly return
     the column as binary.

With the availability of `BINARY' and `VARBINARY' data types, it is
important that we respect the metadata returned by the sever. However,
we are aware that some existing applications may break with this
change, so we are creating a connection string option to enable or
disable it.  By default, Connector/Net 5.1 respects the binary flags
returned by the server. You might need to make small changes to your
application to accommodate this change.

In the event that the changes required to your application would be too
large, you can add 'respect binary flags=false' to your connection
string. This causes the connector to use the prior behavior. In a
nutshell, that behavior was that any column that is marked as string,
regardless of binary flags, will be returned as string. Only columns
that are specifically marked as a `BLOB' will be returned as `BLOB'.


File: manual.info,  Node: connector-net-using-character-sets,  Next: connector-net-medium-trust,  Prev: connector-net-programming-binary-issues,  Up: connector-net-programming

20.2.5.28 Character Sets
........................

*Treating Binary Blobs As UTF8*

MySQL doesn't currently support 4 byte UTF8 sequences. This makes it
difficult to represent some multi-byte languages such as Japanese. To
try and alleviate this, Connector/Net now supports a mode where binary
blobs can be treated as strings.

To do this, you set the 'Treat Blobs As UTF8' connection string keyword
to yes. This is all that needs to be done to enable conversion of all
binary blobs to UTF8 strings. To convert only some of your blob
columns, you can make use of the 'BlobAsUTF8IncludePattern' and
'BlobAsUTF8ExcludePattern' keywords. Set these to a regular expression
pattern that matches the column names to include or exclude
respectively.

When the regular expression patterns both match a single column, the
include pattern is applied before the exclude pattern. The result, in
this case, would be that the column would be excluded.  Also, be aware
that this mode does not apply to columns of type `BINARY' or
`VARBINARY' and also do not apply to nonbinary `BLOB' columns.

Currently, this mode only applies to reading strings out of MySQL.  To
insert 4-byte UTF8 strings into blob columns, use the .NET
`Encoding.GetBytes' function to convert your string to a series of
bytes. You can then set this byte array as a parameter for a `BLOB'
column.


File: manual.info,  Node: connector-net-medium-trust,  Next: connector-net-programming-tracing,  Prev: connector-net-using-character-sets,  Up: connector-net-programming

20.2.5.29 Working with medium trust
...................................

.NET applications operate under a given trust level. Normal desktop
applications operate under full trust while web applications that are
hosted in shared environments are normally run under the medium trust
level. Some hosting providers host shared applications in their own app
pools and allow the application to run under full trust, but this seems
to be the exception rather than the rule.

Connector/Net versions prior to 5.0.8 and 5.1.3 were not compatible
with medium trust hosting. Starting with these versions, Connector/Net
can be used under medium trust hosting that has been modified to allow
the use of sockets for communication. By default, medium trust does not
include `SocketPermission'. Connector/Net uses sockets to talk with the
MySQL server so it is required that a new trust level be created that
is an exact clone of medium trust but that has `SocketPermission' added.


File: manual.info,  Node: connector-net-programming-tracing,  Next: connector-net-programming-bulk-loader,  Prev: connector-net-medium-trust,  Up: connector-net-programming

20.2.5.30 Using the MySQL Connector/Net Trace Source Object
...........................................................

* Menu:

* connector-net-programming-tracing-mysql::  Viewing MySQL Trace Information
* connector-net-programming-tracing-mysql-custom-listeners::  Building Custom Listeners

MySQL Connector/Net 6.2 introduced support for .NET 2.0 compatible
tracing, using `TraceSource' objects.

The .NET 2.0 tracing architecture consists of four main parts:

   * _Source_ - This is the originator of the trace information. The
     source is used to send trace messages.  The name of the source
     provided by MySQL Connector/Net is `mysql'.

   * _Switch_ - This defines the level of trace information to emit.
     Typically, this is specified in the `app.config' file, so that it
     is not necessary to recompile an application to change the trace
     level.

   * _Listener_ - Trace listeners define where the trace information
     will be written to. Supported listeners include, for example, the
     Visual Studio Output window, the Windows Event Log, and the
     console.

   * _Filter_ - Filters can be attached to listeners. Filters determine
     the level of trace information that will be written. While a
     switch defines the level of information that will be written to
     all listeners, a filter can be applied on a per-listener basis,
     giving finer grained control of trace information.

To use tracing a `TraceSource' object first needs to be created. To
create a `TraceSource' object in MySQL Connector/Net you would use code
similar to the following:

     TraceSource ts = new TraceSource("mysql");

To enable trace messages, configure a trace switch. There are three
main switch classes, `BooleanSwitch', `SourceSwitch', and
`TraceSwitch'. Trace switches also have associated with them a trace
level enumeration, these are `Off', `Error', `Warning', `Info', and
`Verbose'. The following code snippet illustrates creating a switch:

     ts.Switch = new SourceSwitch("MySwitch", "Verbose");

This creates a `SourceSwitch', called `MySwitch', and sets the trace
level to `Verbose', meaning that all trace messages will be written.

It is convenient to be able to change the trace level without having to
recompile the code. This is achieved by specifying the trace level in
application configuration file, `app.config'. You then simply need to
specify the desired trace level in the configuration file and restart
the application. The trace source is configured within the
`system.diagnostics' section of the file. The following XML snippet
illustrates this:


     <configuration>
       ...
       <system.diagnostics>
         <sources>
           <source name="mysql" switchName="MySwitch"
                   switchType="System.Diagnostics.SourceSwitch" />
           ...
         </sources>
         <switches>
           <add name="MySwitch" value="Verbose"/>
           ...
         </switches>
       </system.diagnostics>
       ...
     </configuration>

By default trace information is written to the Output window of
Microsoft Visual Studio. However, there are a wide range of listeners
than can be attached to the trace source, so that trace messages can be
written out to various destinations. It is also possible to create
custom listeners to allow trace messages to be written to other
destinations as mobile devices and web services.  A commonly used
example of a listener is `ConsoleTraceListener', which writes trace
messages to the console.

To add a listener at run time you can use code such as the following:

     ts.Listeners.Add(new ConsoleTraceListener());

You can then call methods on trace source object to generate trace
information. For example, the `TraceInformation()', `TraceEvent()', or
`TraceData()' methods can be used.

The `TraceInformation()' method simply prints a string passed as a
parameter. The `TraceEvent()' method, as well as the optional
informational string, requires a `TraceEventType' value to be passed to
indicate the trace message type, and also an application specific ID.
The `TraceEventType' can have a value of `Verbose', `Information',
`Warning', `Error', and `Critical'. Using the `TraceData()' method you
can pass any object, for example an exception object, instead of a
message.

To ensure than these generated trace messages gets flushed from the
trace source buffers to listeners, you need to invoke the `Flush()'
method. When you are finished using a trace source, you should call the
`Close()' method. The `Close()' method first calls `Flush()', to ensure
any remaining data is written out. It then frees up resources, and
closes the listeners associated with the trace source.

     ts.TraceInformation("Informational message");
     ts.TraceEvent(TraceEventType.Error, 3, "Optional error message");
     ts.TraceData(TraceEventType.Error, 3, ex); // pass exception object
     ts.Flush();
     ...
     ts.Close();


File: manual.info,  Node: connector-net-programming-tracing-mysql,  Next: connector-net-programming-tracing-mysql-custom-listeners,  Prev: connector-net-programming-tracing,  Up: connector-net-programming-tracing

20.2.5.31 Viewing MySQL Trace Information
.........................................

This section describes how to set up your application to view MySQL
trace information.

The first thing you need to do is create a suitable `app.config' file
for your application. An example is shown in the following code:


     <?xml version="1.0" encoding="utf-8" ?>
     <configuration>
       <system.diagnostics>
         <sources>
           <source name="mysql" switchName="SourceSwitch"
             switchType="System.Diagnostics.SourceSwitch" >
             <listeners>
               <add name="console" />
               <remove name ="Default" />
             </listeners>
           </source>
         </sources>
         <switches>
           <!-- You can set the level at which tracing is to occur -->
           <add name="SourceSwitch" value="Verbose" />
           <!-- You can turn tracing off -->
           <!--add name="SourceSwitch" value="Off" -->
         </switches>
         <sharedListeners>
           <add name="console"
             type="System.Diagnostics.ConsoleTraceListener"
             initializeData="false"/>
         </sharedListeners>
       </system.diagnostics>
     </configuration>

This ensures a suitable trace source is created, along with a switch.
The switch level in this case is set to `Verbose' to display the
maximum amount of information.

In the application the only other step required is to add
`logging=true' to the connection string. An example application could
be:

     using System;
     using System.Collections.Generic;
     using System.Linq;
     using System.Text;
     using System.Diagnostics;
     using MySql.Data;
     using MySql.Data.MySqlClient;
     using MySql.Web;

     namespace ConsoleApplication1
     {
         class Program
         {
             static void Main(string[] args)
             {

                 string connStr = "server=localhost;user=root;database=world;port=3306;password=******;logging=true;";
                 MySqlConnection conn = new MySqlConnection(connStr);
                 try
                 {
                     Console.WriteLine("Connecting to MySQL...");
                     conn.Open();

                     string sql = "SELECT Name, HeadOfState FROM Country WHERE Continent='Oceania'";
                     MySqlCommand cmd = new MySqlCommand(sql, conn);
                     MySqlDataReader rdr = cmd.ExecuteReader();

                     while (rdr.Read())
                     {
                         Console.WriteLine(rdr[0] + " -- " + rdr[1]);
                     }

                     rdr.Close();

                     conn.Close();
                 }
                 catch (Exception ex)
                 {
                     Console.WriteLine(ex.ToString());
                 }
                 Console.WriteLine("Done.");
             }
         }
     }

This simple application will then generate the following output:

     Connecting to MySQL...
     mysql Information: 1 : 1: Connection Opened: connection string = 'server=localhost;User Id=root;database=world;port=3306
     ;password=******;logging=True'
     mysql Information: 3 : 1: Query Opened: SHOW VARIABLES
     mysql Information: 4 : 1: Resultset Opened: field(s) = 2, affected rows = -1, inserted id = -1
     mysql Information: 5 : 1: Resultset Closed. Total rows=272, skipped rows=0, size (bytes)=7058
     mysql Information: 6 : 1: Query Closed
     mysql Information: 3 : 1: Query Opened: SHOW COLLATION
     mysql Information: 4 : 1: Resultset Opened: field(s) = 6, affected rows = -1, inserted id = -1
     mysql Information: 5 : 1: Resultset Closed. Total rows=127, skipped rows=0, size (bytes)=4102
     mysql Information: 6 : 1: Query Closed
     mysql Information: 3 : 1: Query Opened: SET character_set_results=NULL
     mysql Information: 4 : 1: Resultset Opened: field(s) = 0, affected rows = 0, inserted id = 0
     mysql Information: 5 : 1: Resultset Closed. Total rows=0, skipped rows=0, size (bytes)=0
     mysql Information: 6 : 1: Query Closed
     mysql Information: 10 : 1: Set Database: world
     mysql Information: 3 : 1: Query Opened: SELECT Name, HeadOfState FROM Country WHERE Continent='Oceania'
     mysql Information: 4 : 1: Resultset Opened: field(s) = 2, affected rows = -1, inserted id = -1
     American Samoa -- George W. Bush
     Australia -- Elisabeth II
     ...
     Wallis and Futuna -- Jacques Chirac
     Vanuatu -- John Bani
     United States Minor Outlying Islands -- George W. Bush
     mysql Information: 5 : 1: Resultset Closed. Total rows=28, skipped rows=0, size (bytes)=788
     mysql Information: 6 : 1: Query Closed
     Done.
     mysql Information: 2 : 1: Connection Closed

The first number displayed in the trace message corresponds to the
MySQL event type:

Event                  Description
1                      ConnectionOpened: connection string
2                      ConnectionClosed:
3                      QueryOpened: mysql server thread
                       id, query text
4                      ResultOpened: field count, affected
                       rows (-1 if select), inserted id (-1
                       if select)
5                      ResultClosed: total rows read, rows
                       skipped, size of resultset in bytes
6                      QueryClosed:
7                      StatementPrepared: prepared sql,
                       statement id
8                      StatementExecuted: statement id,
                       mysql server thread id
9                      StatementClosed: statement id
10                     NonQuery: [varies]
11                     UsageAdvisorWarning: usage advisor
                       flag. NoIndex = 1, BadIndex = 2,
                       SkippedRows = 3, SkippedColumns =
                       4, FieldConversion = 5.
12                     Warning: level, code, message
13                     Error: error number, error message

The second number displayed in the trace message is the connection
count.

Although this example uses the `ConsoleTraceListener', any of the other
standard listeners could have been used. Another possibility is to
create a custom listener that uses the information passed using the
`TraceEvent' method. For example, a custom trace listener could be
created to perform active monitoring of the MySQL event messages,
rather than simply writing these to an output device.

It is also possible to add listeners to the MySQL Trace Source at run
time. This can be done with the following code:

     MySqlTrace.Listeners.Add(new ConsoleTraceListener());

MySQL Connector/Net 6.3.2 introduced the ability to switch tracing on
and off at run time. This can be achieved using the calls
`MySqlTrace.EnableQueryAnalyzer(string host, int postInterval)' and
`MySqlTrace.DisableQueryAnalyzer()'. The parameter `host' is the URL of
the MySQL Enterprise Monitor server to monitor. The parameter
`postInterval' is how often the data should be periodically posted to
MySQL Enterprise Monitor, in seconds.


File: manual.info,  Node: connector-net-programming-tracing-mysql-custom-listeners,  Prev: connector-net-programming-tracing-mysql,  Up: connector-net-programming-tracing

20.2.5.32 Building Custom Listeners
...................................

To build custom listeners that work with the MySQL Connector/Net Trace
Source, it is necessary to understand the key methods used, and the
event data formats used.

The main method involved in passing trace messages is the
`TraceSource.TraceEvent' method. This has the prototype:

     public void TraceEvent(
         TraceEventType eventType,
         int id,
         string format,
         params Object[] args
     )

This trace source method will process the list of attached listeners
and call the listener's TraceListener.TraceEvent method. The prototype
for the `TraceListener.TraceEvent' method is as follows:

     public virtual void TraceEvent(
         TraceEventCache eventCache,
         string source,
         TraceEventType eventType,
         int id,
         string format,
         params Object[] args
     )

The first three parameters are used in the standard as defined by
Microsoft (http://msdn.microsoft.com/en-us/library/d193webf.aspx). The
last three parameters contain MySQL-specific trace information. Each of
these parameters is now discussed in more detail.

*`int id'*

This is a MySQL-specific identifier. It identifies the MySQL event type
that has occurred, resulting in a trace message being generated. This
value is defined by the `MySqlTraceEventType' public enum contained in
the MySQL Connector/Net code:

     public enum MySqlTraceEventType : int
     {
         ConnectionOpened = 1,
         ConnectionClosed,
         QueryOpened,
         ResultOpened,
         ResultClosed,
         QueryClosed,
         StatementPrepared,
         StatementExecuted,
         StatementClosed,
         NonQuery,
         UsageAdvisorWarning,
         Warning,
         Error
     }

The MySQL event type also determines the contents passed using the
parameter `params Object[] args'. The nature of the `args' parameters
are described in further detail in the following material.

*`string format'*

This is the format string that contains zero or more format items,
which correspond to objects in the args array. This would be used by a
listener such as `ConsoleTraceListener' to write a message to the
output device.

*`params Object[] args'*

This is a list of objects that depends on the MySQL event type, `id'.
However, the first parameter passed using this list is always the
driver id. The driver id is a unique number that is incremented each
time the connector is opened.  This enables groups of queries on the
same connection to be identified. The parameters that follow driver id
depend of the MySQL event id, and are as follows:

MySQL-specific event   Arguments (params Object[] args)
type                   
ConnectionOpened       Connection string
ConnectionClosed       No additional parameters
QueryOpened            mysql server thread id, query text
ResultOpened           field count, affected rows (-1 if
                       select), inserted id (-1 if select)
ResultClosed           total rows read, rows skipped, size
                       of resultset in bytes
QueryClosed            No additional parameters
StatementPrepared      prepared sql, statement id
StatementExecuted      statement id, mysql server thread id
StatementClosed        statement id
NonQuery               Varies
UsageAdvisorWarning    usage advisor flag. NoIndex = 1,
                       BadIndex = 2, SkippedRows = 3,
                       SkippedColumns = 4, FieldConversion
                       = 5.
Warning                level, code, message
Error                  error number, error message

This information will allow you to create custom trace listeners that
can actively monitor the MySQL-specific events.


File: manual.info,  Node: connector-net-programming-bulk-loader,  Prev: connector-net-programming-tracing,  Up: connector-net-programming

20.2.5.33 Using the Bulk Loader
...............................

MySQL Connector/Net features a bulk loader class that wraps the MySQL
statement `LOAD DATA INFILE'. This gives MySQL Connector/Net the ability
to load a data file from a local or remote host to the server. The
class concerned is `MySqlBulkLoader'. This class has various methods,
the main one being `load' to cause the specified file to be loaded to
the server. Various parameters can be set to control how the data file
is processed.  This is achieved through setting various properties of
the class.  For example, the field separator used, such as comma or
tab, can be specified, along with the record terminator, such as
newline.

The following code shows a simple example of using the
`MySqlBulkLoader' class. First an empty table needs to be created, in
this case in the `test' database:

     CREATE TABLE Career (
            Name VARCHAR(100) NOT NULL,
            Age INTEGER,
            Profession VARCHAR(200)
     );

A simple tab-delimited data file is also created (it could use any
other field delimiter such as comma):

     Table Career in Test Database
     Name	Age	Profession

     Tony	47	Technical Writer
     Ana	43	Nurse
     Fred	21	IT Specialist
     Simon	45	Hairy Biker

Note that with this test file the first three lines will need to be
ignored, as they do not contain table data. This can be achieved using
the `NumberOfLinesToSkip' property. This file can then be loaded and
used to populate the `Career' table in the `test' database:

     using System;
     using System.Text;
     using MySql.Data;
     using MySql.Data.MySqlClient;

     namespace ConsoleApplication1
     {
         class Program
         {
             static void Main(string[] args)
             {

                 string connStr = "server=localhost;user=root;database=test;port=3306;password=******;";
                 MySqlConnection conn = new MySqlConnection(connStr);

                 MySqlBulkLoader bl = new MySqlBulkLoader(conn);
                 bl.TableName = "Career";
                 bl.FieldTerminator = "\t";
                 bl.LineTerminator = "\n";
                 bl.FileName = "c:/career_data.txt";
                 bl.NumberOfLinesToSkip = 3;

                 try
                 {
                     Console.WriteLine("Connecting to MySQL...");
                     conn.Open();

                     // Upload data from file
                     int count = bl.Load();
                     Console.WriteLine(count + " lines uploaded.");

                     string sql = "SELECT Name, Age, Profession FROM Career";
                     MySqlCommand cmd = new MySqlCommand(sql, conn);
                     MySqlDataReader rdr = cmd.ExecuteReader();

                     while (rdr.Read())
                     {
                         Console.WriteLine(rdr[0] + " -- " + rdr[1] + " -- " + rdr[2]);
                     }

                     rdr.Close();

                     conn.Close();
                 }
                 catch (Exception ex)
                 {
                     Console.WriteLine(ex.ToString());
                 }
                 Console.WriteLine("Done.");
             }
         }
     }

Further information on `LOAD DATA INFILE' can be found in *Note
load-data::. Further information on `MySqlBulkLoader' can be found in
the reference documentation that was included with your connector.


File: manual.info,  Node: connector-net-connection-options,  Next: connector-net-ref,  Prev: connector-net-programming,  Up: connector-net

20.2.6 Connector/Net Connection String Options Reference
--------------------------------------------------------

Name                      Default Description
`Allow Batch'             true    When true, multiple SQL statements can
                                  be sent with one command execution.
                                  -Note- Starting with MySQL 4.1.1, batch
                                  statements should be separated by the
                                  server-defined separator character.
                                  Commands sent to earlier versions of
                                  MySQL should be separated with ';'.
`Allow User Variables'    false   Setting this to `true' indicates that
                                  the provider expects user variables in
                                  the SQL. This option was added in
                                  Connector/Net version 5.2.2.
`Allow Zero Datetime'     false   If set to `True',
                                  `MySqlDataReader.GetValue()' will
                                  return a `MySqlDateTime' object for
                                  date or datetime columns that have
                                  illegal values, such as zero datetime
                                  values, and a `System.DateTime' object
                                  for legal values. If set to `False' (the
                                  default setting) it will cause a
                                  `System.DateTime' object to be returned
                                  for all legal values and an exception
                                  to be thrown for illegal values, such
                                  as zero datetime values.
`AutoEnlist'              true    If `AutoEnlist' is set to `true', which
                                  is the default, a connection opened
                                  using `TransactionScope' participates
                                  in this scope, it commits when the
                                  scope commits and rolls back if
                                  `TransactionScope' does not commit.
                                  However, this feature is considered
                                  security sensitive and therefore cannot
                                  be used in a medium trust environment.
`BlobAsUTF8ExcludePattern'null    
`BlobAsUTF8IncludePattern'null    
`CertificateFile'         null    This option specifies the path to a
                                  certificate file in PFX format. For an
                                  example of usage see *Note
                                  connector-net-tutorials-ssl::. Was
                                  introduced with 6.2.1.
`CertificatePassword'     null    This option enables you to specify a
                                  password which is used in conjunction
                                  with a certificate specified using the
                                  option `CertificateFile'. For an
                                  example of usage see *Note
                                  connector-net-tutorials-ssl::. Was
                                  introduced with 6.2.1.
`Certificate Store        null    This option enables you to access a
Location'                         certificate held in a personal store,
                                  rather than use a certificate file and
                                  password combination. For an example of
                                  usage see *Note
                                  connector-net-tutorials-ssl::. Was
                                  introduced with 6.2.1.
`Certificate Thumbprint'  null    This option enables you to specify a
                                  certificate thumbprint to ensure
                                  correct identifcation of a certificate
                                  contained within a personal store. For
                                  an example of usage see *Note
                                  connector-net-tutorials-ssl::. Was
                                  introduced with 6.2.1.
`CharSet', `Character             Specifies the character set that should
Set'                              be used to encode all queries sent to
                                  the server. Resultsets are still
                                  returned in the character set of the
                                  data returned.
`Connect Timeout',        15      The length of time (in seconds) to wait
`Connection Timeout'              for a connection to the server before
                                  terminating the attempt and generating
                                  an error.
`Connection Reset'        false   If true, the connection state will be
                                  reset when it is retrieved from the
                                  pool. If set to false this avoids
                                  making an additional server round trip
                                  when obtaining a connection, but the
                                  connection state is not reset.
`Convert Zero Datetime'   false   True to have
                                  `MySqlDataReader.GetValue()' and
                                  `MySqlDataReader.GetDateTime()' return
                                  DateTime.MinValue for date or datetime
                                  columns that have illegal values.
`Default Command Timeout' 30      Sets the default value of the command
                                  timeout to be used. This does not
                                  supercede the individual command
                                  timeout property on an individual
                                  command object. If you set the command
                                  timeout property, that will be used.
                                  This option was added in Connector/Net
                                  5.1.4
`Encrypt', `UseSSL'       false   For Connector/Net 5.0.3 and later, when
                                  `true', SSL encryption is used for all
                                  data sent between the client and server
                                  if the server has a certificate
                                  installed. Recognized values are `true',
                                  `false', `yes', and `no'. In versions
                                  before 5.0.3, this option had no
                                  effect. From version 6.2.1 this option
                                  is deprecated and is replaced by `SSL
                                  Mode'. However, the option is still
                                  supported if used. If this option is
                                  set to true it is equivalent to `SSL
                                  Mode = Preferred'.
`FunctionsReturnString'   false   This will cause the connector to return
                                  binary/varbinary values as strings, if
                                  they do not have a tablename in the
                                  metadata.
`Host', `Server', `Data   localhostThe name or network address of the
Source', `DataSource',            instance of MySQL to which to connect.
`Address', `Addr',                Multiple hosts can be specified
`Network Address'                 separated by &.  This can be useful
                                  where multiple MySQL servers are
                                  configured for replication and you are
                                  not concerned about the precise server
                                  you are connecting to. No attempt is
                                  made by the provider to synchronize
                                  writes to the database so care should
                                  be taken when using this option. In Unix
                                  environment with Mono, this can be a
                                  fully qualified path to MySQL socket
                                  file name. With this configuration, the
                                  Unix socket will be used instead of
                                  TCP/IP socket. Currently only a single
                                  socket name can be given so accessing
                                  MySQL in a replicated environment using
                                  Unix sockets is not currently supported.
`Ignore Prepare'          true    When true, instructs the provider to
                                  ignore any calls to
                                  `MySqlCommand.Prepare()'. This option is
                                  provided to prevent issues with
                                  corruption of the statements when use
                                  with server side prepared statements.
                                  If you want to use server-side prepare
                                  statements, set this option to false.
                                  This option was added in Connector/Net
                                  5.0.3 and Connector/Net 1.0.9.
`Initial Catalog',        mysql   The case-sensitive name of the database
`Database'                        to use initially.
`Interactive,             false   If set to true the client is
InteractiveSession'               interactive. An interactive client is
                                  one where the server variable
                                  `CLIENT_INTERACTIVE' is set. If an
                                  interactive client is set, the
                                  `wait_timeout' variable is set to the
                                  value of `interactive_timeout'. The
                                  client will then timeout after this
                                  period of inactivity. More details can
                                  be found in the server manual *Note
                                  server-system-variables::.
`Logging'                 false   When true, various pieces of
                                  information is output to any configured
                                  TraceListeners. See *Note
                                  connector-net-programming-tracing:: for
                                  further details.
`Old Guids'               false   This option was introduced in
                                  Connector/Net 6.1.1. The backend
                                  representation of a GUID type was
                                  changed from `BINARY(16)' to
                                  `CHAR(36)'. This was done to allow
                                  developers to use the server function
                                  `UUID()' to populate a GUID table -
                                  `UUID()' generates a 36-character
                                  string.  Developers of older
                                  applications can add 'Old Guids=true' to
                                  the connection string to use a GUID of
                                  data type `BINARY(16)'.
`Old Syntax', `OldSyntax' false   This option was deprecated in
                                  Connector/Net 5.2.2. All code should now
                                  be written using the '@' symbol as the
                                  parameter marker.
`Password', `pwd'                 The password for the MySQL account
                                  being used.
`Persist Security Info'   false   When set to `false' or `no' (strongly
                                  recommended), security-sensitive
                                  information, such as the password, is
                                  not returned as part of the connection
                                  if the connection is open or has ever
                                  been in an open state.  Resetting the
                                  connection string resets all connection
                                  string values including the password.
                                  Recognized values are `true', `false',
                                  `yes', and `no'.
`Pipe Name', `Pipe'       mysql   When set to the name of a named pipe,
                                  the `MySqlConnection' will attempt to
                                  connect to MySQL on that named
                                  pipe.This settings only applies to the
                                  Windows platform.
`Port'                    3306    The port MySQL is using to listen for
                                  connections. This value is ignored if
                                  Unix socket is used.
`Procedure Cache Size'    25      Sets the size of the stored procedure
                                  cache. By default, Connector/Net will
                                  store the metadata (input/output data
                                  types) about the last 25 stored
                                  procedures used. To disable the stored
                                  procedure cache, set the value to zero
                                  (0). This option was added in
                                  Connector/Net 5.0.2 and Connector/Net
                                  1.0.9.
`Protocol'                socket  Specifies the type of connection to
                                  make to the server. Values can be:
                                  `socket' or `tcp' for a socket
                                  connection, `pipe' for a named pipe
                                  connection, `unix' for a Unix socket
                                  connection, `memory' to use MySQL shared
                                  memory.
`Respect Binary Flags'    true    Setting this option to `false' means
                                  that Connector/Net will ignore a
                                  column's binary flags as set by the
                                  server.  This option was added in
                                  Connector/Net version 5.1.3.
`Shared Memory Name'      MYSQL   The name of the shared memory object to
                                  use for communication if the connection
                                  protocol is set to memory.
`Sql Server Mode'         false   Allow SQL Server syntax. When set to
                                  `true' enables Connector/Net to support
                                  square brackets around symbols instead
                                  of backticks. This enables Visual
                                  Studio wizards that bracket symbols
                                  with [] to work with Connector/Net.
                                  This option incurs a performance hit,
                                  so should only be used if necessary.
                                  This option was added in version 6.3.1.
`SSL Mode'                None    This option has the following values:
                                  
                                     * *None* - do not use SSL.
                                  
                                     * *Preferred* - use SSL if the
                                       server supports it, but allow
                                       connection in all cases.
                                  
                                     * *Required* - Always use SSL. Deny
                                       connection if server does not
                                       support SSL.
                                  
                                     * *VerifyCA* - Always use SSL.
                                       Validate the CA but tolerate name
                                       mismatch.
                                  
                                     * *VerifyFull* - Always use SSL.
                                       Fail if the host name is not
                                       correct.
                                  This option was introduced in MySQL
                                  Connector/Net 6.2.1.
`TreatBlobsAsUTF8'        false   
`Treat Tiny As Boolean'   true    Setting this value to `false' indicates
                                  that `TINYINT(1)' will be treated as an
                                  *Note `INT': numeric-types. See also
                                  *Note numeric-type-overview:: for a
                                  further explanation of the *Note
                                  `TINYINT': numeric-types.  and *Note
                                  `BOOL': numeric-types. data types.
`Use Affected Rows'       false   When `true' the connection will report
                                  changed rows instead of found rows.
                                  This option was added in Connector/Net
                                  version 5.2.6.
`Use Procedure Bodies'    true    When set to `true', the default value,
                                  MySQL Connector/Net expects the body of
                                  the procedure to be viewable. This
                                  enables it to determine the parameter
                                  types and order. The option should be
                                  set to `false' when the user connecting
                                  to the database does not have the
                                  `SELECT' privileges for the
                                  `mysql.proc' (stored procedures) table,
                                  or cannot view `I_S.ROUTINES'. In this
                                  case, MySQL Connector/Net will not be
                                  able to determine the types and order of
                                  the parameters, and must be alerted to
                                  this fact by setting this option to
                                  `false'. When set to `false', MySQL
                                  Connector/Net will not rely on this
                                  information being available when the
                                  procedure is called.  Because MySQL
                                  Connector/Net will not be able to
                                  determine this information, you should
                                  explicitly set the types of all the
                                  parameters before the call and the
                                  parameters should be added to the
                                  command in the same order as they
                                  appear in the procedure definition.
                                  This option was added in MySQL
                                  Connector/Net 5.0.4 and MySQL
                                  Connector/Net 1.0.10.
`User Id', `Username',            The MySQL login account being used.
`Uid', `User name'                
`Use Compression'         false   Setting this option to `true' enables
                                  compression of packets exchanged
                                  between the client and the server. This
                                  exchange is defined by the MySQL
                                  client/server protocol.
                                  
                                  Compression is used if both client and
                                  server support ZLIB compression, and
                                  the client has requested compression
                                  using this option.
                                  
                                  A compressed packet header is: packet
                                  length (3 bytes), packet number (1
                                  byte), and Uncompressed Packet Length (3
                                  bytes). The Uncompressed Packet Length
                                  is the number of bytes in the original,
                                  uncompressed packet. If this is zero
                                  then the data in this packet has not
                                  been compressed.  When the compression
                                  protocol is in use, either the client
                                  or the server may compress packets.
                                  However, compression will not occur if
                                  the compressed length is greater than
                                  the original length. Thus, some packets
                                  will contain compressed data while
                                  other packets will not.
`Use Usage Advisor'       false   
`Use Performance Monitor' false   

The following table lists the valid names for connection pooling values
within the `ConnectionString'. For more information about connection
pooling, see Connection Pooling for the MySQL Data Provider.

Name                      Default Description
`Cache Server             false   Specifies whether server variables
Configuration',                   should be updated when a pooled
`CacheServerConfiguration',        connection is returned. Turning this on
`CacheServerConfig'               will yield faster opens but will also
                                  not catch any server changes made by
                                  other connections.
`Connection Lifetime'     0       When a connection is returned to the
                                  pool, its creation time is compared
                                  with the current time, and the
                                  connection is destroyed if that time
                                  span (in seconds) exceeds the value
                                  specified by `Connection Lifetime'.
                                  This is useful in clustered
                                  configurations to force load balancing
                                  between a running server and a server
                                  just brought online. A value of zero
                                  (0) causes pooled connections to have
                                  the maximum connection timeout.
`Max Pool Size'           100     The maximum number of connections
                                  allowed in the pool.
`Min Pool Size'           0       The minimum number of connections
                                  allowed in the pool.
`Pooling'                 true    When `true', the `MySqlConnection'
                                  object is drawn from the appropriate
                                  pool, or if necessary, is created and
                                  added to the appropriate pool.
                                  Recognized values are `true', `false',
                                  `yes', and `no'.


File: manual.info,  Node: connector-net-ref,  Next: connector-net-support,  Prev: connector-net-connection-options,  Up: connector-net

20.2.7 Connector/Net API Reference
----------------------------------

* Menu:

* connector-net-ref-mysqlclient::  `MySql.Data.MySqlClient'
* connector-net-ref-types::      `MySql.Data.Types'

This section of the manual contains a complete reference to the
Connector/Net ADO.NET component, automatically generated from the
embedded documentation.


File: manual.info,  Node: connector-net-ref-mysqlclient,  Next: connector-net-ref-types,  Prev: connector-net-ref,  Up: connector-net-ref

20.2.7.1 `MySql.Data.MySqlClient'
.................................

* Menu:

* connector-net-ref-mysqlclienthierarchy::  `MySql.Data.MySqlClientHierarchy'
* connector-net-ref-mysqlclient-mysqlcommand::  `MySqlCommand' Class
* connector-net-ref-mysqlclient-mysqlcommandbuilder::  `MySqlCommandBuilder' Class
* connector-net-ref-mysqlclient-mysqlexception::  `MySqlException' Class
* connector-net-ref-mysqlclient-mysqlhelper::  `MySqlHelper' Class
* connector-net-ref-mysqlclient-mysqlerrorcode::  `MySqlErrorCode' Enumeration

*Note Namespace hierarchy: connector-net-ref-mysqlclienthierarchy.

*Classes*

Class                                Description
*Note MySqlCommand:                  
connector-net-ref-mysqlclient-mysqlcommand.
*Note MySqlCommandBuilder:           
connector-net-ref-mysqlclient-mysqlcommandbuilder.
*Note MySqlConnection:               
connector-net-ref-mysqlclient-mysqlconnection.
*Note MySqlDataAdapter:              
connector-net-ref-mysqlclient-mysqldataadapter.
*Note MySqlDataReader:               Provides a means of reading a
connector-net-ref-mysqlclient-mysqldatareader.forward-only stream of rows from a
                                     MySQL database. This class cannot
                                     be inherited.
*Note MySqlError:                    Collection of error codes that can
connector-net-ref-mysqlclient-mysqlerror.be returned by the server
*Note MySqlException:                The exception that is thrown when
connector-net-ref-mysqlclient-mysqlexception.MySQL returns an error. This class
                                     cannot be inherited.
*Note MySqlHelper:                   Helper class that makes it easier
connector-net-ref-mysqlclient-mysqlhelper.to work with the provider.
*Note MySqlInfoMessageEventArgs:     Provides data for the InfoMessage
connector-net-ref-mysqlclient-mysqlinfomessageeventargs.event. This class cannot be
                                     inherited.
*Note MySqlParameter:                Represents a parameter to a *Note
connector-net-ref-mysqlclient-mysqlparameter.MySqlCommand:
                                     connector-net-ref-mysqlclient-mysqlcommand
                                     , and optionally, its mapping to
                                     DataSetcolumns. This class cannot
                                     be inherited.
*Note MySqlParameterCollection:      Represents a collection of
connector-net-ref-mysqlclient-mysqlparametercollection.parameters relevant to a *Note
                                     MySqlCommand:
                                     connector-net-ref-mysqlclient-mysqlcommand.
                                     as well as their respective
                                     mappings to columns in a DataSet.
                                     This class cannot be inherited.
*Note MySqlRowUpdatedEventArgs:      Provides data for the RowUpdated
connector-net-ref-mysqlclient-mysqlrowupdatedeventargs.event. This class cannot be
                                     inherited.
*Note MySqlRowUpdatingEventArgs:     Provides data for the RowUpdating
connector-net-ref-mysqlclient-mysqlrowupdatingeventargs.event. This class cannot be
                                     inherited.
*Note MySqlTransaction:              
connector-net-ref-mysqlclient-mysqltransaction.

*Delegates*

Delegate                             Description
*Note MySqlInfoMessageEventHandler:  Represents the method that will
connector-net-ref-mysqlclient-mysqlinfomessageeventhandler.handle the *Note InfoMessage:
                                     connector-net-ref-mysqlclient-mysqlconnection-infomessage.
                                     event of a *Note MySqlConnection:
                                     connector-net-ref-mysqlclient-mysqlconnection.
*Note MySqlRowUpdatedEventHandler:   Represents the method that will
connector-net-ref-mysqlclient-mysqlrowupdatedeventhandler.handle the RowUpdatedevent of a
                                     *Note MySqlDataAdapter:
                                     connector-net-ref-mysqlclient-mysqldataadapter
                                     .
*Note MySqlRowUpdatingEventHandler:  Represents the method that will
connector-net-ref-mysqlclient-mysqlrowupdatingeventhandler.handle the RowUpdatingevent of a
                                     *Note MySqlDataAdapter:
                                     connector-net-ref-mysqlclient-mysqldataadapter
                                     .

*Enumerations*

Enumeration                          Description
*Note MySqlDbType:                   Specifies MySQL specific data type
connector-net-ref-mysqlclient-mysqldbtype.of a field, property, for use in a
                                     *Note MySqlParameter:
                                     connector-net-ref-mysqlclient-mysqlparameter
                                     .
*Note MySqlErrorCode:                
connector-net-ref-mysqlclient-mysqlerrorcode.


File: manual.info,  Node: connector-net-ref-mysqlclienthierarchy,  Next: connector-net-ref-mysqlclient-mysqlcommand,  Prev: connector-net-ref-mysqlclient,  Up: connector-net-ref-mysqlclient

20.2.7.2 `MySql.Data.MySqlClientHierarchy'
..........................................

*See Also*

*Note MySql.Data.MySqlClient Namespace: connector-net-ref-mysqlclient.


File: manual.info,  Node: connector-net-ref-mysqlclient-mysqlcommand,  Next: connector-net-ref-mysqlclient-mysqlcommandbuilder,  Prev: connector-net-ref-mysqlclienthierarchy,  Up: connector-net-ref-mysqlclient

20.2.7.3 `MySqlCommand' Class
.............................

* Menu:

* connector-net-ref-mysqlclient-mysqlcommandmembers::  `MySqlCommand' Members

For a list of all members of this type, see *Note MySqlCommand Members:
connector-net-ref-mysqlclient-mysqlcommandmembers .

*Syntax: Visual Basic*

     NotInheritable Public Class MySqlCommand_
       Inherits Component_
       Implements IDbCommand, ICloneable

*Syntax: C#*

     public sealed class MySqlCommand : Component, IDbCommand, ICloneable

*Thread Safety*

Public static (Shared in Visual Basic) members of this type are safe
for multithreaded operations. Instance members are not guaranteed to be
thread-safe.

*Requirements*

Namespace: *Note MySql.Data.MySqlClient: connector-net-ref-mysqlclient.

Assembly: MySql.Data (in MySql.Data.dll)

*See Also*

*Note MySqlCommand Members:
connector-net-ref-mysqlclient-mysqlcommandmembers, *Note
MySql.Data.MySqlClient Namespace: connector-net-ref-mysqlclient.


File: manual.info,  Node: connector-net-ref-mysqlclient-mysqlcommandmembers,  Prev: connector-net-ref-mysqlclient-mysqlcommand,  Up: connector-net-ref-mysqlclient-mysqlcommand

20.2.7.4 `MySqlCommand' Members
...............................

* Menu:

* connector-net-ref-mysqlclient-mysqlcommandconstructor::  `MySqlCommand' Constructor
* connector-net-ref-mysqlclient-mysqlcommand-commandtext::  CommandText Property
* connector-net-ref-mysqlclient-mysqlcommand-commandtimeout::  CommandTimeout Property
* connector-net-ref-mysqlclient-mysqlcommand-commandtype::  CommandType Property
* connector-net-ref-mysqlclient-mysqlcommand-connection::  Connection Property
* connector-net-ref-mysqlclient-mysqlcommand-isprepared::  IsPrepared Property
* connector-net-ref-mysqlclient-mysqlcommand-parameters::  Parameters Property
* connector-net-ref-mysqlclient-mysqlcommand-transaction::  Transaction Property
* connector-net-ref-mysqlclient-mysqlcommand-updatedrowsource::  UpdatedRowSource Property
* connector-net-ref-mysqlclient-mysqlcommand-cancel::  `MySqlCommand.Cancel' Method
* connector-net-ref-mysqlclient-mysqlcommand-createparameter::  `MySqlCommand.CreateParameter' Method
* connector-net-ref-mysqlclient-mysqlcommand-executenonquery::  `MySqlCommand.ExecuteNonQuery' Method
* connector-net-ref-mysqlclient-mysqlcommand-executereader-overloads::  ExecuteReader Method
* connector-net-ref-mysqlclient-mysqlcommand-executescalar::  `MySqlCommand.ExecuteScalar' Method
* connector-net-ref-mysqlclient-mysqlcommand-prepare::  `MySqlCommand.Prepare' Method

*Note MySqlCommand overview: connector-net-ref-mysqlclient-mysqlcommand.

*Public Instance Constructors*

*Note MySqlCommand:                  Overloaded. Initializes a new
connector-net-ref-mysqlclient-mysqlcommandconstructor.instance of the MySqlCommand class.

*Public Instance Properties*

*Note CommandText:                   
connector-net-ref-mysqlclient-mysqlcommand-commandtext.
*Note CommandTimeout:                
connector-net-ref-mysqlclient-mysqlcommand-commandtimeout.
*Note CommandType:                   
connector-net-ref-mysqlclient-mysqlcommand-commandtype.
*Note Connection:                    
connector-net-ref-mysqlclient-mysqlcommand-connection.
Container(inherited from Component)  Gets the IContainerthat contains
                                     the Component.
*Note IsPrepared:                    
connector-net-ref-mysqlclient-mysqlcommand-isprepared.
*Note Parameters:                    
connector-net-ref-mysqlclient-mysqlcommand-parameters.
Site(inherited from Component)       Gets or sets the ISiteof the
                                     Component.
*Note Transaction:                   
connector-net-ref-mysqlclient-mysqlcommand-transaction.
*Note UpdatedRowSource:              
connector-net-ref-mysqlclient-mysqlcommand-updatedrowsource.

*Public Instance Methods*

*Note Cancel:                        Attempts to cancel the execution of
connector-net-ref-mysqlclient-mysqlcommand-cancel.a MySqlCommand. This operation is
                                     not supported.
CreateObjRef(inherited from          Creates an object that contains all
MarshalByRefObject)                  the relevant information required to
                                     generate a proxy used to
                                     communicate with a remote object.
*Note CreateParameter:               Creates a new instance of a *Note
connector-net-ref-mysqlclient-mysqlcommand-createparameter.MySqlParameter:
                                     connector-net-ref-mysqlclient-mysqlparameter.
                                     object.
Dispose(inherited from Component)    Releases all resources used by the
                                     Component.
Equals(inherited from Object)        Determines whether the specified
                                     Objectis equal to the current
                                     Object.
*Note ExecuteNonQuery:               
connector-net-ref-mysqlclient-mysqlcommand-executenonquery.
*Note ExecuteReader:                 Overloaded.
connector-net-ref-mysqlclient-mysqlcommand-executereader-overloads.
*Note ExecuteScalar:                 
connector-net-ref-mysqlclient-mysqlcommand-executescalar.
GetHashCode(inherited from Object)   Serves as a hash function for a
                                     particular type. GetHashCodeis
                                     suitable for use in hashing
                                     algorithms and data structures like
                                     a hash table.
GetLifetimeService(inherited from    Retrieves the current lifetime
MarshalByRefObject)                  service object that controls the
                                     lifetime policy for this instance.
GetType(inherited from Object)       Gets the Typeof the current
                                     instance.
InitializeLifetimeService(inherited  Obtains a lifetime service object
from MarshalByRefObject)             to control the lifetime policy for
                                     this instance.
*Note Prepare:                       
connector-net-ref-mysqlclient-mysqlcommand-prepare.
ToString(inherited from Component)   Returns a Stringcontaining the name
                                     of the Component, if any. This
                                     method should not be overridden.

*Public Instance Events*

Disposed(inherited from Component)   Adds an event handler to listen to
                                     the Disposedevent on the component.

*See Also*

*Note MySqlCommand Class: connector-net-ref-mysqlclient-mysqlcommand,
*Note MySql.Data.MySqlClient Namespace: connector-net-ref-mysqlclient.


File: manual.info,  Node: connector-net-ref-mysqlclient-mysqlcommandconstructor,  Next: connector-net-ref-mysqlclient-mysqlcommand-commandtext,  Prev: connector-net-ref-mysqlclient-mysqlcommandmembers,  Up: connector-net-ref-mysqlclient-mysqlcommandmembers

20.2.7.5 `MySqlCommand' Constructor
...................................

* Menu:

* connector-net-ref-mysqlclient-mysqlcommandconstructor1::  `MySqlCommand' Constructor ()
* connector-net-ref-mysqlclient-mysqlcommandconstructor2::  `MySqlCommand' Constructor (String)
* connector-net-ref-mysqlclient-mysqlcommandconstructor3::  `MySqlCommand' Constructor
* connector-net-ref-mysqlclient-mysqlcommandconstructor4::  `MySqlCommand' Constructor

Initializes a new instance of the *Note MySqlCommand:
connector-net-ref-mysqlclient-mysqlcommand.  class.

*Overload List*

Initializes a new instance of the *Note MySqlCommand:
connector-net-ref-mysqlclient-mysqlcommand.  class.

   * *Note public MySqlCommand();:
     connector-net-ref-mysqlclient-mysqlcommandconstructor1.

   * *Note public MySqlCommand(string);:
     connector-net-ref-mysqlclient-mysqlcommandconstructor2.

   * *Note public MySqlCommand(string:
     (MySqlConnection);)connector-net-ref-mysqlclient-mysqlcommandconstructor3.

   * *Note public MySqlCommand(string:
     (MySqlConnection)connector-net-ref-mysqlclient-mysqlcommandconstructor4.

*See Also*

*Note MySqlCommand Class: connector-net-ref-mysqlclient-mysqlcommand,
*Note MySql.Data.MySqlClient Namespace: connector-net-ref-mysqlclient.


File: manual.info,  Node: connector-net-ref-mysqlclient-mysqlcommandconstructor1,  Next: connector-net-ref-mysqlclient-mysqlcommandconstructor2,  Prev: connector-net-ref-mysqlclient-mysqlcommandconstructor,  Up: connector-net-ref-mysqlclient-mysqlcommandconstructor

20.2.7.6 `MySqlCommand' Constructor ()
......................................

Initializes a new instance of the *Note MySqlCommand:
connector-net-ref-mysqlclient-mysqlcommand.  class.

*Syntax: Visual Basic*

     Overloads Public Sub New()

*Syntax: C#*

     public MySqlCommand();

*See Also*

*Note MySqlCommand Class: connector-net-ref-mysqlclient-mysqlcommand,
*Note MySql.Data.MySqlClient Namespace: connector-net-ref-mysqlclient,
*Note MySqlCommand Constructor Overload List:
connector-net-ref-mysqlclient-mysqlcommandconstructor.


File: manual.info,  Node: connector-net-ref-mysqlclient-mysqlcommandconstructor2,  Next: connector-net-ref-mysqlclient-mysqlcommandconstructor3,  Prev: connector-net-ref-mysqlclient-mysqlcommandconstructor1,  Up: connector-net-ref-mysqlclient-mysqlcommandconstructor

20.2.7.7 `MySqlCommand' Constructor (String)
............................................

*Syntax: Visual Basic*

     Overloads Public Sub New( _
        ByVal cmdText As String _
     )

*Syntax: C#*

     public MySqlCommand(
     stringcmdText
     );

*See Also*

*Note MySqlCommand Class: connector-net-ref-mysqlclient-mysqlcommand,
*Note MySql.Data.MySqlClient Namespace: connector-net-ref-mysqlclient,
*Note MySqlCommand Constructor Overload List:
connector-net-ref-mysqlclient-mysqlcommandconstructor.


File: manual.info,  Node: connector-net-ref-mysqlclient-mysqlcommandconstructor3,  Next: connector-net-ref-mysqlclient-mysqlcommandconstructor4,  Prev: connector-net-ref-mysqlclient-mysqlcommandconstructor2,  Up: connector-net-ref-mysqlclient-mysqlcommandconstructor

20.2.7.8 `MySqlCommand' Constructor
...................................

* Menu:

* connector-net-ref-mysqlclient-mysqlconnection::  `MySqlConnection' Class

*Syntax: Visual Basic*

     Overloads Public Sub New( _
        ByVal cmdText As String, _
        ByVal connection As MySqlConnection _
     )

*Syntax: C#*

     public MySqlCommand(
     stringcmdText,
     MySqlConnectionconnection
     );

*See Also*

*Note MySqlCommand Class: connector-net-ref-mysqlclient-mysqlcommand,
*Note MySql.Data.MySqlClient Namespace: connector-net-ref-mysqlclient,
*Note MySqlCommand Constructor Overload List:
connector-net-ref-mysqlclient-mysqlcommandconstructor.


File: manual.info,  Node: connector-net-ref-mysqlclient-mysqlconnection,  Prev: connector-net-ref-mysqlclient-mysqlcommandconstructor3,  Up: connector-net-ref-mysqlclient-mysqlcommandconstructor3

20.2.7.9 `MySqlConnection' Class
................................

* Menu:

* connector-net-ref-mysqlclient-mysqlconnectionmembers::  `MySqlConnection' Members

For a list of all members of this type, see *Note MySqlConnection
Members: connector-net-ref-mysqlclient-mysqlconnectionmembers .

*Syntax: Visual Basic*

     NotInheritable Public Class MySqlConnection_
       Inherits Component_
       Implements IDbConnection, ICloneable

*Syntax: C#*

     public sealed class MySqlConnection : Component, IDbConnection, ICloneable

*Thread Safety*

Public static (Shared in Visual Basic) members of this type are safe
for multithreaded operations. Instance members are not guaranteed to be
thread-safe.

*Requirements*

Namespace: *Note MySql.Data.MySqlClient: connector-net-ref-mysqlclient.

Assembly: MySql.Data (in MySql.Data.dll)

*See Also*

*Note MySqlConnection Members:
connector-net-ref-mysqlclient-mysqlconnectionmembers, *Note
MySql.Data.MySqlClient Namespace: connector-net-ref-mysqlclient.


File: manual.info,  Node: connector-net-ref-mysqlclient-mysqlconnectionmembers,  Prev: connector-net-ref-mysqlclient-mysqlconnection,  Up: connector-net-ref-mysqlclient-mysqlconnection

20.2.7.10 `MySqlConnection' Members
...................................

* Menu:

* connector-net-ref-mysqlclient-mysqlconnectionconstructor::  `MySqlConnection' Constructor
* connector-net-ref-mysqlclient-mysqlconnection-connectionstring::  ConnectionString Property
* connector-net-ref-mysqlclient-mysqlconnection-connectiontimeout::  ConnectionTimeout Property
* connector-net-ref-mysqlclient-mysqlconnection-database::  Database Property
* connector-net-ref-mysqlclient-mysqlconnection-datasource::  DataSource Property
* connector-net-ref-mysqlclient-mysqlconnection-serverthread::  ServerThread Property
* connector-net-ref-mysqlclient-mysqlconnection-serverversion::  ServerVersion Property
* connector-net-ref-mysqlclient-mysqlconnection-state::  State Property
* connector-net-ref-mysqlclient-mysqlconnection-usecompression::  UseCompression Property
* connector-net-ref-mysqlclient-mysqlconnection-begintransaction-overloads::  BeginTransaction Method
* connector-net-ref-mysqlclient-mysqlconnection-changedatabase::  `MySqlConnection.ChangeDatabase' Method
* connector-net-ref-mysqlclient-mysqlconnection-close::  `MySqlConnection.Close' Method
* connector-net-ref-mysqlclient-mysqlconnection-createcommand::  `MySqlConnection.CreateCommand' Method
* connector-net-ref-mysqlclient-mysqlconnection-open::  `MySqlConnection.Open' Method
* connector-net-ref-mysqlclient-mysqlconnection-ping::  `MySqlConnection.Ping' Method
* connector-net-ref-mysqlclient-mysqlconnection-infomessage::  `MySqlConnection.InfoMessage' Event
* connector-net-ref-mysqlclient-mysqlconnection-statechange::  `MySqlConnection.StateChange' Event

*Note MySqlConnection overview:
connector-net-ref-mysqlclient-mysqlconnection.

*Public Instance Constructors*

*Note MySqlConnection:               Overloaded. Initializes a new
connector-net-ref-mysqlclient-mysqlconnectionconstructor.instance of the MySqlConnection
                                     class.

*Public Instance Properties*

*Note ConnectionString:              
connector-net-ref-mysqlclient-mysqlconnection-connectionstring.
*Note ConnectionTimeout:             
connector-net-ref-mysqlclient-mysqlconnection-connectiontimeout.
Container(inherited from Component)  Gets the IContainerthat contains
                                     the Component.
*Note Database:                      
connector-net-ref-mysqlclient-mysqlconnection-database.
*Note DataSource:                    Gets the name of the MySQL server
connector-net-ref-mysqlclient-mysqlconnection-datasource.to which to connect.
*Note ServerThread:                  Returns the id of the server thread
connector-net-ref-mysqlclient-mysqlconnection-serverthread.this connection is executing on
*Note ServerVersion:                 
connector-net-ref-mysqlclient-mysqlconnection-serverversion.
Site(inherited from Component)       Gets or sets the ISiteof the
                                     Component.
*Note State:                         
connector-net-ref-mysqlclient-mysqlconnection-state.
*Note UseCompression:                Indicates if this connection should
connector-net-ref-mysqlclient-mysqlconnection-usecompression.use compression when communicating
                                     with the server.

*Public Instance Methods*

*Note BeginTransaction:              Overloaded.
connector-net-ref-mysqlclient-mysqlconnection-begintransaction-overloads.
*Note ChangeDatabase:                
connector-net-ref-mysqlclient-mysqlconnection-changedatabase.
*Note Close:                         
connector-net-ref-mysqlclient-mysqlconnection-close.
*Note CreateCommand:                 
connector-net-ref-mysqlclient-mysqlconnection-createcommand.
CreateObjRef(inherited from          Creates an object that contains all
MarshalByRefObject)                  the relevant information required to
                                     generate a proxy used to
                                     communicate with a remote object.
Dispose(inherited from Component)    Releases all resources used by the
                                     Component.
Equals(inherited from Object)        Determines whether the specified
                                     Objectis equal to the current
                                     Object.
GetHashCode(inherited from Object)   Serves as a hash function for a
                                     particular type. GetHashCodeis
                                     suitable for use in hashing
                                     algorithms and data structures like
                                     a hash table.
GetLifetimeService(inherited from    Retrieves the current lifetime
MarshalByRefObject)                  service object that controls the
                                     lifetime policy for this instance.
GetType(inherited from Object)       Gets the Typeof the current
                                     instance.
InitializeLifetimeService(inherited  Obtains a lifetime service object
from MarshalByRefObject)             to control the lifetime policy for
                                     this instance.
*Note Open:                          
connector-net-ref-mysqlclient-mysqlconnection-open.
*Note Ping:                          Ping
connector-net-ref-mysqlclient-mysqlconnection-ping.
ToString(inherited from Component)   Returns a Stringcontaining the name
                                     of the Component, if any. This
                                     method should not be overridden.

*Public Instance Events*

Disposed(inherited from Component)   Adds an event handler to listen to
                                     the Disposedevent on the component.
*Note InfoMessage:                   
connector-net-ref-mysqlclient-mysqlconnection-infomessage.
*Note StateChange:                   
connector-net-ref-mysqlclient-mysqlconnection-statechange.

*See Also*

*Note MySqlConnection Class:
connector-net-ref-mysqlclient-mysqlconnection, *Note
MySql.Data.MySqlClient Namespace: connector-net-ref-mysqlclient.


File: manual.info,  Node: connector-net-ref-mysqlclient-mysqlconnectionconstructor,  Next: connector-net-ref-mysqlclient-mysqlconnection-connectionstring,  Prev: connector-net-ref-mysqlclient-mysqlconnectionmembers,  Up: connector-net-ref-mysqlclient-mysqlconnectionmembers

20.2.7.11 `MySqlConnection' Constructor
.......................................

* Menu:

* connector-net-ref-mysqlclient-mysqlconnectionconstructor1::  `MySqlConnection' Constructor
* connector-net-ref-mysqlclient-mysqlconnectionconstructor2::  `MySqlConnection' Constructor

Initializes a new instance of the *Note MySqlConnection:
connector-net-ref-mysqlclient-mysqlconnection.  class.

*Overload List*

Initializes a new instance of the *Note MySqlConnection:
connector-net-ref-mysqlclient-mysqlconnection.  class.

   * *Note public MySqlConnection();:
     connector-net-ref-mysqlclient-mysqlconnectionconstructor1.

   * *Note public MySqlConnection(string);:
     connector-net-ref-mysqlclient-mysqlconnectionconstructor2.

*See Also*

*Note MySqlConnection Class:
connector-net-ref-mysqlclient-mysqlconnection, *Note
MySql.Data.MySqlClient Namespace: connector-net-ref-mysqlclient.


File: manual.info,  Node: connector-net-ref-mysqlclient-mysqlconnectionconstructor1,  Next: connector-net-ref-mysqlclient-mysqlconnectionconstructor2,  Prev: connector-net-ref-mysqlclient-mysqlconnectionconstructor,  Up: connector-net-ref-mysqlclient-mysqlconnectionconstructor

20.2.7.12 `MySqlConnection' Constructor
.......................................

Initializes a new instance of the *Note MySqlConnection:
connector-net-ref-mysqlclient-mysqlconnection.  class.

*Syntax: Visual Basic*

     Overloads Public Sub New()

*Syntax: C#*

     public MySqlConnection();

*See Also*

*Note MySqlConnection Class:
connector-net-ref-mysqlclient-mysqlconnection, *Note
MySql.Data.MySqlClient Namespace: connector-net-ref-mysqlclient, *Note
MySqlConnection Constructor Overload List:
connector-net-ref-mysqlclient-mysqlconnectionconstructor.


File: manual.info,  Node: connector-net-ref-mysqlclient-mysqlconnectionconstructor2,  Prev: connector-net-ref-mysqlclient-mysqlconnectionconstructor1,  Up: connector-net-ref-mysqlclient-mysqlconnectionconstructor

20.2.7.13 `MySqlConnection' Constructor
.......................................

*Syntax: Visual Basic*

     Overloads Public Sub New( _
        ByVal connectionString As String _
     )

*Syntax: C#*

     public MySqlConnection(
     stringconnectionString
     );

*See Also*

*Note MySqlConnection Class:
connector-net-ref-mysqlclient-mysqlconnection, *Note
MySql.Data.MySqlClient Namespace: connector-net-ref-mysqlclient, *Note
MySqlConnection Constructor Overload List:
connector-net-ref-mysqlclient-mysqlconnectionconstructor.


File: manual.info,  Node: connector-net-ref-mysqlclient-mysqlconnection-connectionstring,  Next: connector-net-ref-mysqlclient-mysqlconnection-connectiontimeout,  Prev: connector-net-ref-mysqlclient-mysqlconnectionconstructor,  Up: connector-net-ref-mysqlclient-mysqlconnectionmembers

20.2.7.14 ConnectionString Property
...................................

*Syntax: Visual Basic*

     NotOverridable Public Property ConnectionString As String _
     _
       Implements IDbConnection.ConnectionString

*Syntax: C#*

     public string ConnectionString {get; set;}

*Implements*

IDbConnection.ConnectionString

*See Also*

*Note MySqlConnection Class:
connector-net-ref-mysqlclient-mysqlconnection, *Note
MySql.Data.MySqlClient Namespace: connector-net-ref-mysqlclient.


File: manual.info,  Node: connector-net-ref-mysqlclient-mysqlconnection-connectiontimeout,  Next: connector-net-ref-mysqlclient-mysqlconnection-database,  Prev: connector-net-ref-mysqlclient-mysqlconnection-connectionstring,  Up: connector-net-ref-mysqlclient-mysqlconnectionmembers

20.2.7.15 ConnectionTimeout Property
....................................

*Syntax: Visual Basic*

     NotOverridable Public ReadOnly Property ConnectionTimeout As Integer _
     _
       Implements IDbConnection.ConnectionTimeout

*Syntax: C#*

     public int ConnectionTimeout {get;}

*Implements*

IDbConnection.ConnectionTimeout

*See Also*

*Note MySqlConnection Class:
connector-net-ref-mysqlclient-mysqlconnection, *Note
MySql.Data.MySqlClient Namespace: connector-net-ref-mysqlclient.


File: manual.info,  Node: connector-net-ref-mysqlclient-mysqlconnection-database,  Next: connector-net-ref-mysqlclient-mysqlconnection-datasource,  Prev: connector-net-ref-mysqlclient-mysqlconnection-connectiontimeout,  Up: connector-net-ref-mysqlclient-mysqlconnectionmembers

20.2.7.16 Database Property
...........................

*Syntax: Visual Basic*

     NotOverridable Public ReadOnly Property Database As String _
     _
       Implements IDbConnection.Database

*Syntax: C#*

     public string Database {get;}

*Implements*

IDbConnection.Database

*See Also*

*Note MySqlConnection Class:
connector-net-ref-mysqlclient-mysqlconnection, *Note
MySql.Data.MySqlClient Namespace: connector-net-ref-mysqlclient.


File: manual.info,  Node: connector-net-ref-mysqlclient-mysqlconnection-datasource,  Next: connector-net-ref-mysqlclient-mysqlconnection-serverthread,  Prev: connector-net-ref-mysqlclient-mysqlconnection-database,  Up: connector-net-ref-mysqlclient-mysqlconnectionmembers

20.2.7.17 DataSource Property
.............................

Gets the name of the MySQL server to which to connect.

*Syntax: Visual Basic*

     Public ReadOnly Property DataSource As String

*Syntax: C#*

     public string DataSource {get;}

*See Also*

*Note MySqlConnection Class:
connector-net-ref-mysqlclient-mysqlconnection, *Note
MySql.Data.MySqlClient Namespace: connector-net-ref-mysqlclient.


File: manual.info,  Node: connector-net-ref-mysqlclient-mysqlconnection-serverthread,  Next: connector-net-ref-mysqlclient-mysqlconnection-serverversion,  Prev: connector-net-ref-mysqlclient-mysqlconnection-datasource,  Up: connector-net-ref-mysqlclient-mysqlconnectionmembers

20.2.7.18 ServerThread Property
...............................

Returns the id of the server thread this connection is executing on

*Syntax: Visual Basic*

     Public ReadOnly Property ServerThread As Integer

*Syntax: C#*

     public int ServerThread {get;}

*See Also*

*Note MySqlConnection Class:
connector-net-ref-mysqlclient-mysqlconnection, *Note
MySql.Data.MySqlClient Namespace: connector-net-ref-mysqlclient.


File: manual.info,  Node: connector-net-ref-mysqlclient-mysqlconnection-serverversion,  Next: connector-net-ref-mysqlclient-mysqlconnection-state,  Prev: connector-net-ref-mysqlclient-mysqlconnection-serverthread,  Up: connector-net-ref-mysqlclient-mysqlconnectionmembers

20.2.7.19 ServerVersion Property
................................

*Syntax: Visual Basic*

     Public ReadOnly Property ServerVersion As String

*Syntax: C#*

     public string ServerVersion {get;}

*See Also*

*Note MySqlConnection Class:
connector-net-ref-mysqlclient-mysqlconnection, *Note
MySql.Data.MySqlClient Namespace: connector-net-ref-mysqlclient.


File: manual.info,  Node: connector-net-ref-mysqlclient-mysqlconnection-state,  Next: connector-net-ref-mysqlclient-mysqlconnection-usecompression,  Prev: connector-net-ref-mysqlclient-mysqlconnection-serverversion,  Up: connector-net-ref-mysqlclient-mysqlconnectionmembers

20.2.7.20 State Property
........................

*Syntax: Visual Basic*

     NotOverridable Public ReadOnly Property State As ConnectionState _
     _
       Implements IDbConnection.State

*Syntax: C#*

     public System.Data.ConnectionState State {get;}

*Implements*

IDbConnection.State

*See Also*

*Note MySqlConnection Class:
connector-net-ref-mysqlclient-mysqlconnection, *Note
MySql.Data.MySqlClient Namespace: connector-net-ref-mysqlclient.


File: manual.info,  Node: connector-net-ref-mysqlclient-mysqlconnection-usecompression,  Next: connector-net-ref-mysqlclient-mysqlconnection-begintransaction-overloads,  Prev: connector-net-ref-mysqlclient-mysqlconnection-state,  Up: connector-net-ref-mysqlclient-mysqlconnectionmembers

20.2.7.21 UseCompression Property
.................................

Indicates if this connection should use compression when communicating
with the server.

*Syntax: Visual Basic*

     Public ReadOnly Property UseCompression As Boolean

*Syntax: C#*

     public bool UseCompression {get;}

*See Also*

*Note MySqlConnection Class:
connector-net-ref-mysqlclient-mysqlconnection, *Note
MySql.Data.MySqlClient Namespace: connector-net-ref-mysqlclient.


File: manual.info,  Node: connector-net-ref-mysqlclient-mysqlconnection-begintransaction-overloads,  Next: connector-net-ref-mysqlclient-mysqlconnection-changedatabase,  Prev: connector-net-ref-mysqlclient-mysqlconnection-usecompression,  Up: connector-net-ref-mysqlclient-mysqlconnectionmembers

20.2.7.22 BeginTransaction Method
.................................

* Menu:

* connector-net-ref-mysqlclient-mysqlconnection-begintransaction-overload-1::  `MySqlConnection.BeginTransaction' Method
* connector-net-ref-mysqlclient-mysqlconnection-begintransaction-overload-2::  `MySqlConnection.BeginTransaction' Method

*Overload List*

   * *Note public MySqlTransaction BeginTransaction();:
     connector-net-ref-mysqlclient-mysqlconnection-begintransaction-overload-1.

   * *Note public MySqlTransaction BeginTransaction(IsolationLevel);:
     connector-net-ref-mysqlclient-mysqlconnection-begintransaction-overload-2.

*See Also*

*Note MySqlConnection Class:
connector-net-ref-mysqlclient-mysqlconnection, *Note
MySql.Data.MySqlClient Namespace: connector-net-ref-mysqlclient.


File: manual.info,  Node: connector-net-ref-mysqlclient-mysqlconnection-begintransaction-overload-1,  Next: connector-net-ref-mysqlclient-mysqlconnection-begintransaction-overload-2,  Prev: connector-net-ref-mysqlclient-mysqlconnection-begintransaction-overloads,  Up: connector-net-ref-mysqlclient-mysqlconnection-begintransaction-overloads

20.2.7.23 `MySqlConnection.BeginTransaction' Method
...................................................

* Menu:

* connector-net-ref-mysqlclient-mysqltransaction::  `MySqlTransaction' Class

*Syntax: Visual Basic*

     Overloads Public Function BeginTransaction() As MySqlTransaction

*Syntax: C#*

     public MySqlTransaction BeginTransaction();

*See Also*

*Note MySqlConnection Class:
connector-net-ref-mysqlclient-mysqlconnection, *Note
MySql.Data.MySqlClient Namespace: connector-net-ref-mysqlclient, *Note
MySqlConnection.BeginTransaction Overload List:
connector-net-ref-mysqlclient-mysqlconnection-begintransaction-overloads.


File: manual.info,  Node: connector-net-ref-mysqlclient-mysqltransaction,  Prev: connector-net-ref-mysqlclient-mysqlconnection-begintransaction-overload-1,  Up: connector-net-ref-mysqlclient-mysqlconnection-begintransaction-overload-1

20.2.7.24 `MySqlTransaction' Class
..................................

* Menu:

* connector-net-ref-mysqlclient-mysqltransactionmembers::  `MySqlTransaction' Members

For a list of all members of this type, see *Note MySqlTransaction
Members: connector-net-ref-mysqlclient-mysqltransactionmembers .

*Syntax: Visual Basic*

     NotInheritable Public Class MySqlTransaction_
       Implements IDbTransaction, IDisposable

*Syntax: C#*

     public sealed class MySqlTransaction : IDbTransaction, IDisposable

*Thread Safety*

Public static (Sharedin Visual Basic) members of this type are safe for
multithreaded operations.  Instance members are notguaranteed to be
thread-safe.

*Requirements*

Namespace: *Note MySql.Data.MySqlClient: connector-net-ref-mysqlclient.

Assembly: MySql.Data (in MySql.Data.dll)

*See Also*

*Note MySqlTransaction Members:
connector-net-ref-mysqlclient-mysqltransactionmembers, *Note
MySql.Data.MySqlClient Namespace: connector-net-ref-mysqlclient.


File: manual.info,  Node: connector-net-ref-mysqlclient-mysqltransactionmembers,  Prev: connector-net-ref-mysqlclient-mysqltransaction,  Up: connector-net-ref-mysqlclient-mysqltransaction

20.2.7.25 `MySqlTransaction' Members
....................................

* Menu:

* connector-net-ref-mysqlclient-mysqltransaction-connection::  Connection Property
* connector-net-ref-mysqlclient-mysqltransaction-isolationlevel::  IsolationLevel Property
* connector-net-ref-mysqlclient-mysqltransaction-commit::  `MySqlTransaction.Commit' Method
* connector-net-ref-mysqlclient-mysqltransaction-rollback::  `MySqlTransaction.Rollback' Method

*Note MySqlTransaction overview:
connector-net-ref-mysqlclient-mysqltransaction.

*Public Instance Properties*

*Note Connection:                    Gets the *Note MySqlConnection:
connector-net-ref-mysqlclient-mysqltransaction-connection.connector-net-ref-mysqlclient-mysqlconnection.
                                     object associated with the
                                     transaction, or a null reference
                                     (Nothing in Visual Basic) if the
                                     transaction is no longer valid.
*Note IsolationLevel:                Specifies the IsolationLevelfor
connector-net-ref-mysqlclient-mysqltransaction-isolationlevel.this transaction.

*Public Instance Methods*

*Note Commit:                        
connector-net-ref-mysqlclient-mysqltransaction-commit.
Equals(inherited from Object)        Determines whether the specified
                                     Objectis equal to the current
                                     Object.
GetHashCode(inherited from Object)   Serves as a hash function for a
                                     particular type. GetHashCodeis
                                     suitable for use in hashing
                                     algorithms and data structures like
                                     a hash table.
GetType(inherited from Object)       Gets the Typeof the current
                                     instance.
*Note Rollback:                      
connector-net-ref-mysqlclient-mysqltransaction-rollback.
ToString(inherited from Object)      Returns a Stringthat represents the
                                     current Object.

*See Also*

*Note MySqlTransaction Class:
connector-net-ref-mysqlclient-mysqltransaction, *Note
MySql.Data.MySqlClient Namespace: connector-net-ref-mysqlclient.


File: manual.info,  Node: connector-net-ref-mysqlclient-mysqltransaction-connection,  Next: connector-net-ref-mysqlclient-mysqltransaction-isolationlevel,  Prev: connector-net-ref-mysqlclient-mysqltransactionmembers,  Up: connector-net-ref-mysqlclient-mysqltransactionmembers

20.2.7.26 Connection Property
.............................

Gets the *Note MySqlConnection:
connector-net-ref-mysqlclient-mysqlconnection.  object associated with
the transaction, or a null reference (Nothing in Visual Basic) if the
transaction is no longer valid.

*Syntax: Visual Basic*

     Public ReadOnly Property Connection As MySqlConnection

*Syntax: C#*

     public MySqlConnection Connection {get;}

*Property Value*

The *Note MySqlConnection:
connector-net-ref-mysqlclient-mysqlconnection.  object associated with
this transaction.

*Remarks*

A single application may have multiple database connections, each with
zero or more transactions. This property enables you to determine the
connection object associated with a particular transaction created by
*Note BeginTransaction:
connector-net-ref-mysqlclient-mysqlconnection-begintransaction-overload-1
.

*See Also*

*Note MySqlTransaction Class:
connector-net-ref-mysqlclient-mysqltransaction, *Note
MySql.Data.MySqlClient Namespace: connector-net-ref-mysqlclient.


File: manual.info,  Node: connector-net-ref-mysqlclient-mysqltransaction-isolationlevel,  Next: connector-net-ref-mysqlclient-mysqltransaction-commit,  Prev: connector-net-ref-mysqlclient-mysqltransaction-connection,  Up: connector-net-ref-mysqlclient-mysqltransactionmembers

20.2.7.27 IsolationLevel Property
.................................

Specifies the IsolationLevelfor this transaction.

*Syntax: Visual Basic*

     NotOverridable Public ReadOnly Property IsolationLevel As IsolationLevel _
     _
       Implements IDbTransaction.IsolationLevel

*Syntax: C#*

     public System.Data.IsolationLevel IsolationLevel {get;}

*Property Value*

The IsolationLevel for this transaction. The default is ReadCommitted.

*Implements*

IDbTransaction.IsolationLevel

*Remarks*

Parallel transactions are not supported.  Therefore, the IsolationLevel
applies to the entire transaction.

*See Also*

*Note MySqlTransaction Class:
connector-net-ref-mysqlclient-mysqltransaction, *Note
MySql.Data.MySqlClient Namespace: connector-net-ref-mysqlclient.


File: manual.info,  Node: connector-net-ref-mysqlclient-mysqltransaction-commit,  Next: connector-net-ref-mysqlclient-mysqltransaction-rollback,  Prev: connector-net-ref-mysqlclient-mysqltransaction-isolationlevel,  Up: connector-net-ref-mysqlclient-mysqltransactionmembers

20.2.7.28 `MySqlTransaction.Commit' Method
..........................................

*Syntax: Visual Basic*

     NotOverridable Public Sub Commit() _
     _
       Implements IDbTransaction.Commit

*Syntax: C#*

     public void Commit();

*Implements*

IDbTransaction.Commit

*See Also*

*Note MySqlTransaction Class:
connector-net-ref-mysqlclient-mysqltransaction, *Note
MySql.Data.MySqlClient Namespace: connector-net-ref-mysqlclient.


File: manual.info,  Node: connector-net-ref-mysqlclient-mysqltransaction-rollback,  Prev: connector-net-ref-mysqlclient-mysqltransaction-commit,  Up: connector-net-ref-mysqlclient-mysqltransactionmembers

20.2.7.29 `MySqlTransaction.Rollback' Method
............................................

*Syntax: Visual Basic*

     NotOverridable Public Sub Rollback() _
     _
       Implements IDbTransaction.Rollback

*Syntax: C#*

     public void Rollback();

*Implements*

IDbTransaction.Rollback

*See Also*

*Note MySqlTransaction Class:
connector-net-ref-mysqlclient-mysqltransaction, *Note
MySql.Data.MySqlClient Namespace: connector-net-ref-mysqlclient.


File: manual.info,  Node: connector-net-ref-mysqlclient-mysqlconnection-begintransaction-overload-2,  Prev: connector-net-ref-mysqlclient-mysqlconnection-begintransaction-overload-1,  Up: connector-net-ref-mysqlclient-mysqlconnection-begintransaction-overloads

20.2.7.30 `MySqlConnection.BeginTransaction' Method
...................................................

*Syntax: Visual Basic*

     Overloads Public Function BeginTransaction( _
        ByVal iso As IsolationLevel _
     ) As MySqlTransaction

*Syntax: C#*

     public MySqlTransaction BeginTransaction(
     IsolationLeveliso
     );

*See Also*

*Note MySqlConnection Class:
connector-net-ref-mysqlclient-mysqlconnection, *Note
MySql.Data.MySqlClient Namespace: connector-net-ref-mysqlclient, *Note
MySqlConnection.BeginTransaction Overload List:
connector-net-ref-mysqlclient-mysqlconnection-begintransaction-overloads.


File: manual.info,  Node: connector-net-ref-mysqlclient-mysqlconnection-changedatabase,  Next: connector-net-ref-mysqlclient-mysqlconnection-close,  Prev: connector-net-ref-mysqlclient-mysqlconnection-begintransaction-overloads,  Up: connector-net-ref-mysqlclient-mysqlconnectionmembers

20.2.7.31 `MySqlConnection.ChangeDatabase' Method
.................................................

*Syntax: Visual Basic*

     NotOverridable Public Sub ChangeDatabase( _
        ByVal databaseName As String _
     ) _
     _
       Implements IDbConnection.ChangeDatabase

*Syntax: C#*

     public void ChangeDatabase(
     stringdatabaseName
     );

*Implements*

IDbConnection.ChangeDatabase

*See Also*

*Note MySqlConnection Class:
connector-net-ref-mysqlclient-mysqlconnection, *Note
MySql.Data.MySqlClient Namespace: connector-net-ref-mysqlclient.


File: manual.info,  Node: connector-net-ref-mysqlclient-mysqlconnection-close,  Next: connector-net-ref-mysqlclient-mysqlconnection-createcommand,  Prev: connector-net-ref-mysqlclient-mysqlconnection-changedatabase,  Up: connector-net-ref-mysqlclient-mysqlconnectionmembers

20.2.7.32 `MySqlConnection.Close' Method
........................................

*Syntax: Visual Basic*

     NotOverridable Public Sub Close() _
     _
       Implements IDbConnection.Close

*Syntax: C#*

     public void Close();

*Implements*

IDbConnection.Close

*See Also*

*Note MySqlConnection Class:
connector-net-ref-mysqlclient-mysqlconnection, *Note
MySql.Data.MySqlClient Namespace: connector-net-ref-mysqlclient.


File: manual.info,  Node: connector-net-ref-mysqlclient-mysqlconnection-createcommand,  Next: connector-net-ref-mysqlclient-mysqlconnection-open,  Prev: connector-net-ref-mysqlclient-mysqlconnection-close,  Up: connector-net-ref-mysqlclient-mysqlconnectionmembers

20.2.7.33 `MySqlConnection.CreateCommand' Method
................................................

*Syntax: Visual Basic*

     Public Function CreateCommand() As MySqlCommand

*Syntax: C#*

     public MySqlCommand CreateCommand();

*See Also*

*Note MySqlConnection Class:
connector-net-ref-mysqlclient-mysqlconnection, *Note
MySql.Data.MySqlClient Namespace: connector-net-ref-mysqlclient.


File: manual.info,  Node: connector-net-ref-mysqlclient-mysqlconnection-open,  Next: connector-net-ref-mysqlclient-mysqlconnection-ping,  Prev: connector-net-ref-mysqlclient-mysqlconnection-createcommand,  Up: connector-net-ref-mysqlclient-mysqlconnectionmembers

20.2.7.34 `MySqlConnection.Open' Method
.......................................

*Syntax: Visual Basic*

     NotOverridable Public Sub Open() _
     _
       Implements IDbConnection.Open

*Syntax: C#*

     public void Open();

*Implements*

IDbConnection.Open

*See Also*

*Note MySqlConnection Class:
connector-net-ref-mysqlclient-mysqlconnection, *Note
MySql.Data.MySqlClient Namespace: connector-net-ref-mysqlclient.


File: manual.info,  Node: connector-net-ref-mysqlclient-mysqlconnection-ping,  Next: connector-net-ref-mysqlclient-mysqlconnection-infomessage,  Prev: connector-net-ref-mysqlclient-mysqlconnection-open,  Up: connector-net-ref-mysqlclient-mysqlconnectionmembers

20.2.7.35 `MySqlConnection.Ping' Method
.......................................

Ping

*Syntax: Visual Basic*

     Public Function Ping() As Boolean

*Syntax: C#*

     public bool Ping();

*Return Value*

*See Also*

*Note MySqlConnection Class:
connector-net-ref-mysqlclient-mysqlconnection, *Note
MySql.Data.MySqlClient Namespace: connector-net-ref-mysqlclient.


File: manual.info,  Node: connector-net-ref-mysqlclient-mysqlconnection-infomessage,  Next: connector-net-ref-mysqlclient-mysqlconnection-statechange,  Prev: connector-net-ref-mysqlclient-mysqlconnection-ping,  Up: connector-net-ref-mysqlclient-mysqlconnectionmembers

20.2.7.36 `MySqlConnection.InfoMessage' Event
.............................................

* Menu:

* connector-net-ref-mysqlclient-mysqlinfomessageeventhandler::  `MySqlInfoMessageEventHandler' Delegate

*Syntax: Visual Basic*

     Public Event InfoMessage As MySqlInfoMessageEventHandler

*Syntax: C#*

     public event MySqlInfoMessageEventHandler InfoMessage;

*See Also*

*Note MySqlConnection Class:
connector-net-ref-mysqlclient-mysqlconnection, *Note
MySql.Data.MySqlClient Namespace: connector-net-ref-mysqlclient.


File: manual.info,  Node: connector-net-ref-mysqlclient-mysqlinfomessageeventhandler,  Prev: connector-net-ref-mysqlclient-mysqlconnection-infomessage,  Up: connector-net-ref-mysqlclient-mysqlconnection-infomessage

20.2.7.37 `MySqlInfoMessageEventHandler' Delegate
.................................................

* Menu:

* connector-net-ref-mysqlclient-mysqlinfomessageeventargs::  `MySqlInfoMessageEventArgs' Class

Represents the method that will handle the *Note InfoMessage:
connector-net-ref-mysqlclient-mysqlconnection-infomessage.  event of a
*Note MySqlConnection: connector-net-ref-mysqlclient-mysqlconnection .

*Syntax: Visual Basic*

     Public Delegate Sub MySqlInfoMessageEventHandler( _
        ByVal sender As Object, _
        ByVal args As MySqlInfoMessageEventArgs _
     )

*Syntax: C#*

     public delegate void MySqlInfoMessageEventHandler(
     objectsender,
     MySqlInfoMessageEventArgsargs
     );

*Requirements*

Namespace: *Note MySql.Data.MySqlClient: connector-net-ref-mysqlclient.

Assembly: MySql.Data (in MySql.Data.dll)

*See Also*

*Note MySql.Data.MySqlClient Namespace: connector-net-ref-mysqlclient.


File: manual.info,  Node: connector-net-ref-mysqlclient-mysqlinfomessageeventargs,  Prev: connector-net-ref-mysqlclient-mysqlinfomessageeventhandler,  Up: connector-net-ref-mysqlclient-mysqlinfomessageeventhandler

20.2.7.38 `MySqlInfoMessageEventArgs' Class
...........................................

* Menu:

* connector-net-ref-mysqlclient-mysqlinfomessageeventargsmembers::  `MySqlInfoMessageEventArgs' Members

Provides data for the InfoMessage event. This class cannot be inherited.

For a list of all members of this type, see *Note
MySqlInfoMessageEventArgs Members:
connector-net-ref-mysqlclient-mysqlinfomessageeventargsmembers .

*Syntax: Visual Basic*

     Public Class MySqlInfoMessageEventArgs_
       Inherits EventArgs

*Syntax: C#*

     public class MySqlInfoMessageEventArgs : EventArgs

*Thread Safety*

Public static (Sharedin Visual Basic) members of this type are safe for
multithreaded operations.  Instance members are notguaranteed to be
thread-safe.

*Requirements*

Namespace: *Note MySql.Data.MySqlClient: connector-net-ref-mysqlclient.

Assembly: MySql.Data (in MySql.Data.dll)

*See Also*

*Note MySqlInfoMessageEventArgs Members:
connector-net-ref-mysqlclient-mysqlinfomessageeventargsmembers, *Note
MySql.Data.MySqlClient Namespace: connector-net-ref-mysqlclient.


File: manual.info,  Node: connector-net-ref-mysqlclient-mysqlinfomessageeventargsmembers,  Prev: connector-net-ref-mysqlclient-mysqlinfomessageeventargs,  Up: connector-net-ref-mysqlclient-mysqlinfomessageeventargs

20.2.7.39 `MySqlInfoMessageEventArgs' Members
.............................................

* Menu:

* connector-net-ref-mysqlclient-mysqlinfomessageeventargsconstructor::  `MySqlInfoMessageEventArgs' Constructor
* connector-net-ref-mysqlclient-mysqlinfomessageeventargs-errors::  `MySqlInfoMessageEventArgs.errors' Field

*Note MySqlInfoMessageEventArgs overview:
connector-net-ref-mysqlclient-mysqlinfomessageeventargs.

*Public Instance Constructors*

*Note MySqlInfoMessageEventArgs      Initializes a new instance of the
Constructor:                         *Note MySqlInfoMessageEventArgs:
connector-net-ref-mysqlclient-mysqlinfomessageeventargsconstructor.connector-net-ref-mysqlclient-mysqlinfomessageeventargs.
                                     class.

*Public Instance Fields*

*Note errors:                        
connector-net-ref-mysqlclient-mysqlinfomessageeventargs-errors.

*Public Instance Methods*

Equals(inherited from Object)        Determines whether the specified
                                     Objectis equal to the current
                                     Object.
GetHashCode(inherited from Object)   Serves as a hash function for a
                                     particular type. GetHashCodeis
                                     suitable for use in hashing
                                     algorithms and data structures like
                                     a hash table.
GetType(inherited from Object)       Gets the Typeof the current
                                     instance.
ToString(inherited from Object)      Returns a Stringthat represents the
                                     current Object.

*Protected Instance Methods*

Finalize(inherited from Object)      Allows an Objectto attempt to free
                                     resources and perform other cleanup
                                     operations before the Objectis
                                     reclaimed by garbage collection.
MemberwiseClone(inherited from       Creates a shallow copy of the
Object)                              current Object.

*See Also*

*Note MySqlInfoMessageEventArgs Class:
connector-net-ref-mysqlclient-mysqlinfomessageeventargs, *Note
MySql.Data.MySqlClient Namespace: connector-net-ref-mysqlclient.


File: manual.info,  Node: connector-net-ref-mysqlclient-mysqlinfomessageeventargsconstructor,  Next: connector-net-ref-mysqlclient-mysqlinfomessageeventargs-errors,  Prev: connector-net-ref-mysqlclient-mysqlinfomessageeventargsmembers,  Up: connector-net-ref-mysqlclient-mysqlinfomessageeventargsmembers

20.2.7.40 `MySqlInfoMessageEventArgs' Constructor
.................................................

Initializes a new instance of the *Note MySqlInfoMessageEventArgs:
connector-net-ref-mysqlclient-mysqlinfomessageeventargs.  class.

*Syntax: Visual Basic*

     Public Sub New()

*Syntax: C#*

     public MySqlInfoMessageEventArgs();

*See Also*

*Note MySqlInfoMessageEventArgs Class:
connector-net-ref-mysqlclient-mysqlinfomessageeventargs, *Note
MySql.Data.MySqlClient Namespace: connector-net-ref-mysqlclient.


File: manual.info,  Node: connector-net-ref-mysqlclient-mysqlinfomessageeventargs-errors,  Prev: connector-net-ref-mysqlclient-mysqlinfomessageeventargsconstructor,  Up: connector-net-ref-mysqlclient-mysqlinfomessageeventargsmembers

20.2.7.41 `MySqlInfoMessageEventArgs.errors' Field
..................................................

* Menu:

* connector-net-ref-mysqlclient-mysqlerror::  `MySqlError' Class

*Syntax: Visual Basic*

     Public errors As MySqlError()

*Syntax: C#*

     public MySqlError[] errors;

*See Also*

*Note MySqlInfoMessageEventArgs Class:
connector-net-ref-mysqlclient-mysqlinfomessageeventargs, *Note
MySql.Data.MySqlClient Namespace: connector-net-ref-mysqlclient.


File: manual.info,  Node: connector-net-ref-mysqlclient-mysqlerror,  Prev: connector-net-ref-mysqlclient-mysqlinfomessageeventargs-errors,  Up: connector-net-ref-mysqlclient-mysqlinfomessageeventargs-errors

20.2.7.42 `MySqlError' Class
............................

* Menu:

* connector-net-ref-mysqlclient-mysqlerrormembers::  `MySqlError' Members

Collection of error codes that can be returned by the server

For a list of all members of this type, see *Note MySqlError Members:
connector-net-ref-mysqlclient-mysqlerrormembers .

*Syntax: Visual Basic*

     Public Class MySqlError

*Syntax: C#*

     public class MySqlError

*Thread Safety*

Public static (Shared in Visual Basic) members of this type are safe for
multithreaded operations. Instance members are not guaranteed to be
thread-safe.

*Requirements*

Namespace: *Note MySql.Data.MySqlClient: connector-net-ref-mysqlclient.

Assembly: MySql.Data (in MySql.Data.dll)

*See Also*

*Note MySqlError Members:
connector-net-ref-mysqlclient-mysqlerrormembers, *Note
MySql.Data.MySqlClient Namespace: connector-net-ref-mysqlclient.


File: manual.info,  Node: connector-net-ref-mysqlclient-mysqlerrormembers,  Prev: connector-net-ref-mysqlclient-mysqlerror,  Up: connector-net-ref-mysqlclient-mysqlerror

20.2.7.43 `MySqlError' Members
..............................

* Menu:

* connector-net-ref-mysqlclient-mysqlerrorconstructor::  `MySqlError' Constructor
* connector-net-ref-mysqlclient-mysqlerror-code::  Code Property
* connector-net-ref-mysqlclient-mysqlerror-level::  Level Property
* connector-net-ref-mysqlclient-mysqlerror-message::  Message Property

*Note MySqlError overview: connector-net-ref-mysqlclient-mysqlerror.

*Public Instance Constructors*

*Note MySqlError Constructor:        
connector-net-ref-mysqlclient-mysqlerrorconstructor.

*Public Instance Properties*

*Note Code:                          Error code
connector-net-ref-mysqlclient-mysqlerror-code.
*Note Level:                         Error level
connector-net-ref-mysqlclient-mysqlerror-level.
*Note Message:                       Error message
connector-net-ref-mysqlclient-mysqlerror-message.

*Public Instance Methods*

Equals(inherited from Object)        Determines whether the specified
                                     Objectis equal to the current
                                     Object.
GetHashCode(inherited from Object)   Serves as a hash function for a
                                     particular type. GetHashCodeis
                                     suitable for use in hashing
                                     algorithms and data structures like
                                     a hash table.
GetType(inherited from Object)       Gets the Typeof the current
                                     instance.
ToString(inherited from Object)      Returns a Stringthat represents the
                                     current Object.

*Protected Instance Methods*

Finalize(inherited from Object)      Allows an Objectto attempt to free
                                     resources and perform other cleanup
                                     operations before the Objectis
                                     reclaimed by garbage collection.
MemberwiseClone(inherited from       Creates a shallow copy of the
Object)                              current Object.

*See Also*

*Note MySqlError Class: connector-net-ref-mysqlclient-mysqlerror, *Note
MySql.Data.MySqlClient Namespace: connector-net-ref-mysqlclient.


File: manual.info,  Node: connector-net-ref-mysqlclient-mysqlerrorconstructor,  Next: connector-net-ref-mysqlclient-mysqlerror-code,  Prev: connector-net-ref-mysqlclient-mysqlerrormembers,  Up: connector-net-ref-mysqlclient-mysqlerrormembers

20.2.7.44 `MySqlError' Constructor
..................................

*Syntax: Visual Basic*

     Public Sub New( _
        ByVal level As String, _
        ByVal code As Integer, _
        ByVal message As String _
     )

*Syntax: C#*

     public MySqlError(
     stringlevel,
     intcode,
     stringmessage
     );

*Parameters*

   * `level':

   * `code':

   * `message':

*See Also*

*Note MySqlError Class: connector-net-ref-mysqlclient-mysqlerror, *Note
MySql.Data.MySqlClient Namespace: connector-net-ref-mysqlclient.


File: manual.info,  Node: connector-net-ref-mysqlclient-mysqlerror-code,  Next: connector-net-ref-mysqlclient-mysqlerror-level,  Prev: connector-net-ref-mysqlclient-mysqlerrorconstructor,  Up: connector-net-ref-mysqlclient-mysqlerrormembers

20.2.7.45 Code Property
.......................

Error code

*Syntax: Visual Basic*

     Public ReadOnly Property Code As Integer

*Syntax: C#*

     public int Code {get;}

*See Also*

*Note MySqlError Class: connector-net-ref-mysqlclient-mysqlerror, *Note
MySql.Data.MySqlClient Namespace: connector-net-ref-mysqlclient.


File: manual.info,  Node: connector-net-ref-mysqlclient-mysqlerror-level,  Next: connector-net-ref-mysqlclient-mysqlerror-message,  Prev: connector-net-ref-mysqlclient-mysqlerror-code,  Up: connector-net-ref-mysqlclient-mysqlerrormembers

20.2.7.46 Level Property
........................

Error level

*Syntax: Visual Basic*

     Public ReadOnly Property Level As String

*Syntax: C#*

     public string Level {get;}

*See Also*

*Note MySqlError Class: connector-net-ref-mysqlclient-mysqlerror, *Note
MySql.Data.MySqlClient Namespace: connector-net-ref-mysqlclient.


File: manual.info,  Node: connector-net-ref-mysqlclient-mysqlerror-message,  Prev: connector-net-ref-mysqlclient-mysqlerror-level,  Up: connector-net-ref-mysqlclient-mysqlerrormembers

20.2.7.47 Message Property
..........................

Error message

*Syntax: Visual Basic*

     Public ReadOnly Property Message As String

*Syntax: C#*

     public string Message {get;}

*See Also*

*Note MySqlError Class: connector-net-ref-mysqlclient-mysqlerror, *Note
MySql.Data.MySqlClient Namespace: connector-net-ref-mysqlclient.


File: manual.info,  Node: connector-net-ref-mysqlclient-mysqlconnection-statechange,  Prev: connector-net-ref-mysqlclient-mysqlconnection-infomessage,  Up: connector-net-ref-mysqlclient-mysqlconnectionmembers

20.2.7.48 `MySqlConnection.StateChange' Event
.............................................

*Syntax: Visual Basic*

     Public Event StateChange As StateChangeEventHandler

*Syntax: C#*

     public event StateChangeEventHandler StateChange;

*See Also*

*Note MySqlConnection Class:
connector-net-ref-mysqlclient-mysqlconnection, *Note
MySql.Data.MySqlClient Namespace: connector-net-ref-mysqlclient.


File: manual.info,  Node: connector-net-ref-mysqlclient-mysqlcommandconstructor4,  Prev: connector-net-ref-mysqlclient-mysqlcommandconstructor3,  Up: connector-net-ref-mysqlclient-mysqlcommandconstructor

20.2.7.49 `MySqlCommand' Constructor
....................................

*Syntax: Visual Basic*

     Overloads Public Sub New( _
        ByVal cmdText As String, _
        ByVal connection As MySqlConnection, _
        ByVal transaction As MySqlTransaction _
     )

*Syntax: C#*

     public MySqlCommand(
     stringcmdText,
     MySqlConnectionconnection,
     MySqlTransactiontransaction
     );

*See Also*

*Note MySqlCommand Class: connector-net-ref-mysqlclient-mysqlcommand,
*Note MySql.Data.MySqlClient Namespace: connector-net-ref-mysqlclient,
*Note MySqlCommand Constructor Overload List:
connector-net-ref-mysqlclient-mysqlcommandconstructor.


File: manual.info,  Node: connector-net-ref-mysqlclient-mysqlcommand-commandtext,  Next: connector-net-ref-mysqlclient-mysqlcommand-commandtimeout,  Prev: connector-net-ref-mysqlclient-mysqlcommandconstructor,  Up: connector-net-ref-mysqlclient-mysqlcommandmembers

20.2.7.50 CommandText Property
..............................

*Syntax: Visual Basic*

     NotOverridable Public Property CommandText As String _
     _
       Implements IDbCommand.CommandText

*Syntax: C#*

     public string CommandText {get; set;}

*Implements*

IDbCommand.CommandText

*See Also*

*Note MySqlCommand Class: connector-net-ref-mysqlclient-mysqlcommand,
*Note MySql.Data.MySqlClient Namespace: connector-net-ref-mysqlclient.


File: manual.info,  Node: connector-net-ref-mysqlclient-mysqlcommand-commandtimeout,  Next: connector-net-ref-mysqlclient-mysqlcommand-commandtype,  Prev: connector-net-ref-mysqlclient-mysqlcommand-commandtext,  Up: connector-net-ref-mysqlclient-mysqlcommandmembers

20.2.7.51 CommandTimeout Property
.................................

*Syntax: Visual Basic*

     NotOverridable Public Property CommandTimeout As Integer _
     _
       Implements IDbCommand.CommandTimeout

*Syntax: C#*

     public int CommandTimeout {get; set;}

*Implements*

IDbCommand.CommandTimeout

*See Also*

*Note MySqlCommand Class: connector-net-ref-mysqlclient-mysqlcommand,
*Note MySql.Data.MySqlClient Namespace: connector-net-ref-mysqlclient.


File: manual.info,  Node: connector-net-ref-mysqlclient-mysqlcommand-commandtype,  Next: connector-net-ref-mysqlclient-mysqlcommand-connection,  Prev: connector-net-ref-mysqlclient-mysqlcommand-commandtimeout,  Up: connector-net-ref-mysqlclient-mysqlcommandmembers

20.2.7.52 CommandType Property
..............................

*Syntax: Visual Basic*

     NotOverridable Public Property CommandType As CommandType _
     _
       Implements IDbCommand.CommandType

*Syntax: C#*

     public System.Data.CommandType CommandType {get; set;}

*Implements*

IDbCommand.CommandType

*See Also*

*Note MySqlCommand Class: connector-net-ref-mysqlclient-mysqlcommand,
*Note MySql.Data.MySqlClient Namespace: connector-net-ref-mysqlclient.


File: manual.info,  Node: connector-net-ref-mysqlclient-mysqlcommand-connection,  Next: connector-net-ref-mysqlclient-mysqlcommand-isprepared,  Prev: connector-net-ref-mysqlclient-mysqlcommand-commandtype,  Up: connector-net-ref-mysqlclient-mysqlcommandmembers

20.2.7.53 Connection Property
.............................

*Syntax: Visual Basic*

     Public Property Connection As MySqlConnection

*Syntax: C#*

     public MySqlConnection Connection {get; set;}

*See Also*

*Note MySqlCommand Class: connector-net-ref-mysqlclient-mysqlcommand,
*Note MySql.Data.MySqlClient Namespace: connector-net-ref-mysqlclient.


File: manual.info,  Node: connector-net-ref-mysqlclient-mysqlcommand-isprepared,  Next: connector-net-ref-mysqlclient-mysqlcommand-parameters,  Prev: connector-net-ref-mysqlclient-mysqlcommand-connection,  Up: connector-net-ref-mysqlclient-mysqlcommandmembers

20.2.7.54 IsPrepared Property
.............................

*Syntax: Visual Basic*

     Public ReadOnly Property IsPrepared As Boolean

*Syntax: C#*

     public bool IsPrepared {get;}

*See Also*

*Note MySqlCommand Class: connector-net-ref-mysqlclient-mysqlcommand,
*Note MySql.Data.MySqlClient Namespace: connector-net-ref-mysqlclient.


File: manual.info,  Node: connector-net-ref-mysqlclient-mysqlcommand-parameters,  Next: connector-net-ref-mysqlclient-mysqlcommand-transaction,  Prev: connector-net-ref-mysqlclient-mysqlcommand-isprepared,  Up: connector-net-ref-mysqlclient-mysqlcommandmembers

20.2.7.55 Parameters Property
.............................

* Menu:

* connector-net-ref-mysqlclient-mysqlparametercollection::  `MySqlParameterCollection' Class

*Syntax: Visual Basic*

     Public ReadOnly Property Parameters As MySqlParameterCollection

*Syntax: C#*

     public MySqlParameterCollection Parameters {get;}

*See Also*

*Note MySqlCommand Class: connector-net-ref-mysqlclient-mysqlcommand,
*Note MySql.Data.MySqlClient Namespace: connector-net-ref-mysqlclient.


File: manual.info,  Node: connector-net-ref-mysqlclient-mysqlparametercollection,  Prev: connector-net-ref-mysqlclient-mysqlcommand-parameters,  Up: connector-net-ref-mysqlclient-mysqlcommand-parameters

20.2.7.56 `MySqlParameterCollection' Class
..........................................

* Menu:

* connector-net-ref-mysqlclient-mysqlparametercollectionmembers::  `MySqlParameterCollection' Members

Represents a collection of parameters relevant to a *Note MySqlCommand:
connector-net-ref-mysqlclient-mysqlcommand.  as well as their
respective mappings to columns in a DataSet. This class cannot be
inherited.

For a list of all members of this type, see *Note
MySqlParameterCollection Members:
connector-net-ref-mysqlclient-mysqlparametercollectionmembers .

*Syntax: Visual Basic*

     NotInheritable Public Class MySqlParameterCollection_
       Inherits MarshalByRefObject_
       Implements IDataParameterCollection, IList, ICollection, IEnumerable

*Syntax: C#*

     public sealed class MySqlParameterCollection : MarshalByRefObject, IDataParameterCollection, IList, ICollection, IEnumerable

*Thread Safety*

Public static (Shared in Visual Basic) members of this type are safe
for multithreaded operations. Instance members are not guaranteed to be
thread-safe.

*Requirements*

Namespace: *Note MySql.Data.MySqlClient: connector-net-ref-mysqlclient.

Assembly: MySql.Data (in MySql.Data.dll)

*See Also*

*Note MySqlParameterCollection Members:
connector-net-ref-mysqlclient-mysqlparametercollectionmembers, *Note
MySql.Data.MySqlClient Namespace: connector-net-ref-mysqlclient.


File: manual.info,  Node: connector-net-ref-mysqlclient-mysqlparametercollectionmembers,  Prev: connector-net-ref-mysqlclient-mysqlparametercollection,  Up: connector-net-ref-mysqlclient-mysqlparametercollection

20.2.7.57 `MySqlParameterCollection' Members
............................................

* Menu:

* connector-net-ref-mysqlclient-mysqlparametercollectionconstructor::  `MySqlParameterCollection' Constructor
* connector-net-ref-mysqlclient-mysqlparametercollection-count::  Count Property
* connector-net-ref-mysqlclient-mysqlparametercollectionitem::  Item Property
* connector-net-ref-mysqlclient-mysqlparametercollection-add-overloads::  Add Method
* connector-net-ref-mysqlclient-mysqlparametercollection-clear::  `MySqlParameterCollection.Clear' Method
* connector-net-ref-mysqlclient-mysqlparametercollection-contains-overloads::  Contains Method
* connector-net-ref-mysqlclient-mysqlparametercollection-copyto::  `MySqlParameterCollection.CopyTo' Method
* connector-net-ref-mysqlclient-mysqlparametercollection-indexof-overloads::  IndexOf Method
* connector-net-ref-mysqlclient-mysqlparametercollection-insert::  `MySqlParameterCollection.Insert' Method
* connector-net-ref-mysqlclient-mysqlparametercollection-remove::  `MySqlParameterCollection.Remove' Method
* connector-net-ref-mysqlclient-mysqlparametercollection-removeat-overloads::  RemoveAt Method

*Note MySqlParameterCollection overview:
connector-net-ref-mysqlclient-mysqlparametercollection.

*Public Instance Constructors*

*Note MySqlParameterCollection       Initializes a new instance of the
Constructor:                         *Note MySqlParameterCollection:
connector-net-ref-mysqlclient-mysqlparametercollectionconstructor.connector-net-ref-mysqlclient-mysqlparametercollection.
                                     class.

*Public Instance Properties*

*Note Count:                         Gets the number of MySqlParameter
connector-net-ref-mysqlclient-mysqlparametercollection-count.objects in the collection.
*Note Item:                          Overloaded. Gets the *Note
connector-net-ref-mysqlclient-mysqlparametercollectionitem.MySqlParameter:
                                     connector-net-ref-mysqlclient-mysqlparameter.
                                     with a specified attribute. In C#,
                                     this property is the indexer for the
                                     *Note MySqlParameterCollection:
                                     connector-net-ref-mysqlclient-mysqlparametercollection.
                                     class.

*Public Instance Methods*

*Note Add:                           Overloaded. Adds the specified
connector-net-ref-mysqlclient-mysqlparametercollection-add-overloads.*Note MySqlParameter:
                                     connector-net-ref-mysqlclient-mysqlparameter.
                                     object to the *Note
                                     MySqlParameterCollection:
                                     connector-net-ref-mysqlclient-mysqlparametercollection
                                     .
*Note Clear:                         Removes all items from the
connector-net-ref-mysqlclient-mysqlparametercollection-clear.collection.
*Note Contains:                      Overloaded. Gets a value indicating
connector-net-ref-mysqlclient-mysqlparametercollection-contains-overloads.whether a *Note MySqlParameter:
                                     connector-net-ref-mysqlclient-mysqlparameter.
                                     exists in the collection.
*Note CopyTo:                        Copies MySqlParameter objects from
connector-net-ref-mysqlclient-mysqlparametercollection-copyto.the MySqlParameterCollection to the
                                     specified array.
CreateObjRef(inherited from          Creates an object that contains all
MarshalByRefObject)                  the relevant information required to
                                     generate a proxy used to
                                     communicate with a remote object.
Equals(inherited from Object)        Determines whether the specified
                                     Objectis equal to the current
                                     Object.
GetHashCode(inherited from Object)   Serves as a hash function for a
                                     particular type. GetHashCodeis
                                     suitable for use in hashing
                                     algorithms and data structures like
                                     a hash table.
GetLifetimeService(inherited from    Retrieves the current lifetime
MarshalByRefObject)                  service object that controls the
                                     lifetime policy for this instance.
GetType(inherited from Object)       Gets the Typeof the current
                                     instance.
*Note IndexOf:                       Overloaded. Gets the location of a
connector-net-ref-mysqlclient-mysqlparametercollection-indexof-overloads.*Note MySqlParameter:
                                     connector-net-ref-mysqlclient-mysqlparameter.
                                     in the collection.
InitializeLifetimeService(inherited  Obtains a lifetime service object
from MarshalByRefObject)             to control the lifetime policy for
                                     this instance.
*Note Insert:                        Inserts a MySqlParameter into the
connector-net-ref-mysqlclient-mysqlparametercollection-insert.collection at the specified index.
*Note Remove:                        Removes the specified
connector-net-ref-mysqlclient-mysqlparametercollection-remove.MySqlParameter from the collection.
*Note RemoveAt:                      Overloaded. Removes the specified
connector-net-ref-mysqlclient-mysqlparametercollection-removeat-overloads.*Note MySqlParameter:
                                     connector-net-ref-mysqlclient-mysqlparameter.
                                     from the collection.
ToString(inherited from Object)      Returns a Stringthat represents the
                                     current Object.

*See Also*

*Note MySqlParameterCollection Class:
connector-net-ref-mysqlclient-mysqlparametercollection, *Note
MySql.Data.MySqlClient Namespace: connector-net-ref-mysqlclient.


File: manual.info,  Node: connector-net-ref-mysqlclient-mysqlparametercollectionconstructor,  Next: connector-net-ref-mysqlclient-mysqlparametercollection-count,  Prev: connector-net-ref-mysqlclient-mysqlparametercollectionmembers,  Up: connector-net-ref-mysqlclient-mysqlparametercollectionmembers

20.2.7.58 `MySqlParameterCollection' Constructor
................................................

Initializes a new instance of the *Note MySqlParameterCollection:
connector-net-ref-mysqlclient-mysqlparametercollection.  class.

*Syntax: Visual Basic*

     Public Sub New()

*Syntax: C#*

     public MySqlParameterCollection();

*See Also*

*Note MySqlParameterCollection Class:
connector-net-ref-mysqlclient-mysqlparametercollection, *Note
MySql.Data.MySqlClient Namespace: connector-net-ref-mysqlclient.


File: manual.info,  Node: connector-net-ref-mysqlclient-mysqlparametercollection-count,  Next: connector-net-ref-mysqlclient-mysqlparametercollectionitem,  Prev: connector-net-ref-mysqlclient-mysqlparametercollectionconstructor,  Up: connector-net-ref-mysqlclient-mysqlparametercollectionmembers

20.2.7.59 Count Property
........................

Gets the number of MySqlParameter objects in the collection.

*Syntax: Visual Basic*

     NotOverridable Public ReadOnly Property Count As Integer _
     _
       Implements ICollection.Count

*Syntax: C#*

     public int Count {get;}

*Implements*

ICollection.Count

*See Also*

*Note MySqlParameterCollection Class:
connector-net-ref-mysqlclient-mysqlparametercollection, *Note
MySql.Data.MySqlClient Namespace: connector-net-ref-mysqlclient.


File: manual.info,  Node: connector-net-ref-mysqlclient-mysqlparametercollectionitem,  Next: connector-net-ref-mysqlclient-mysqlparametercollection-add-overloads,  Prev: connector-net-ref-mysqlclient-mysqlparametercollection-count,  Up: connector-net-ref-mysqlclient-mysqlparametercollectionmembers

20.2.7.60 Item Property
.......................

* Menu:

* connector-net-ref-mysqlclient-mysqlparameter::  `MySqlParameter' Class
* connector-net-ref-mysqlclient-mysqlparametercollection-item1::  Item Property (Int32)
* connector-net-ref-mysqlclient-mysqlparametercollection-item2::  Item Property (String)

Gets the *Note MySqlParameter:
connector-net-ref-mysqlclient-mysqlparameter.  with a specified
attribute. In C#, this property is the indexer for the *Note
MySqlParameterCollection:
connector-net-ref-mysqlclient-mysqlparametercollection.  class.

*Overload List*

Gets the *Note MySqlParameter:
connector-net-ref-mysqlclient-mysqlparameter.  at the specified index.

   * *Note public MySqlParameter this[int] {get; set;}:
     connector-net-ref-mysqlclient-mysqlparametercollection-item1.

Gets the *Note MySqlParameter:
connector-net-ref-mysqlclient-mysqlparameter.  with the specified name.

   * *Note public MySqlParameter this[string] {get; set;}:
     connector-net-ref-mysqlclient-mysqlparametercollection-item2.

*See Also*

*Note MySqlParameterCollection Class:
connector-net-ref-mysqlclient-mysqlparametercollection, *Note
MySql.Data.MySqlClient Namespace: connector-net-ref-mysqlclient.


File: manual.info,  Node: connector-net-ref-mysqlclient-mysqlparameter,  Next: connector-net-ref-mysqlclient-mysqlparametercollection-item1,  Prev: connector-net-ref-mysqlclient-mysqlparametercollectionitem,  Up: connector-net-ref-mysqlclient-mysqlparametercollectionitem

20.2.7.61 `MySqlParameter' Class
................................

* Menu:

* connector-net-ref-mysqlclient-mysqlparametermembers::  `MySqlParameter' Members

Represents a parameter to a *Note MySqlCommand:
connector-net-ref-mysqlclient-mysqlcommand , and optionally, its
mapping to DataSetcolumns.  This class cannot be inherited.

For a list of all members of this type, see *Note MySqlParameter
Members: connector-net-ref-mysqlclient-mysqlparametermembers .

*Syntax: Visual Basic*

     NotInheritable Public Class MySqlParameter_
       Inherits MarshalByRefObject_
       Implements IDataParameter, IDbDataParameter, ICloneable

*Syntax: C#*

     public sealed class MySqlParameter : MarshalByRefObject, IDataParameter, IDbDataParameter, ICloneable

*Thread Safety*

Public static (Shared in Visual Basic) members of this type are safe
for multithreaded operations.  Instance members are not guaranteed to be
thread-safe.

*Requirements*

Namespace: *Note MySql.Data.MySqlClient: connector-net-ref-mysqlclient.

Assembly: MySql.Data (in MySql.Data.dll)

*See Also*

*Note MySqlParameter Members:
connector-net-ref-mysqlclient-mysqlparametermembers, *Note
MySql.Data.MySqlClient Namespace: connector-net-ref-mysqlclient.


File: manual.info,  Node: connector-net-ref-mysqlclient-mysqlparametermembers,  Prev: connector-net-ref-mysqlclient-mysqlparameter,  Up: connector-net-ref-mysqlclient-mysqlparameter

20.2.7.62 `MySqlParameter' Members
..................................

* Menu:

* connector-net-ref-mysqlclient-mysqlparameterconstructor::  `MySqlParameter' Constructor
* connector-net-ref-mysqlclient-mysqlparameter-dbtype::  DbType Property
* connector-net-ref-mysqlclient-mysqlparameter-direction::  Direction Property
* connector-net-ref-mysqlclient-mysqlparameter-isnullable::  IsNullable Property
* connector-net-ref-mysqlclient-mysqlparameter-isunsigned::  IsUnsigned Property
* connector-net-ref-mysqlclient-mysqlparameter-mysqldbtype::  `MySqlDbType' Property
* connector-net-ref-mysqlclient-mysqlparameter-parametername::  ParameterName Property
* connector-net-ref-mysqlclient-mysqlparameter-precision::  Precision Property
* connector-net-ref-mysqlclient-mysqlparameter-scale::  Scale Property
* connector-net-ref-mysqlclient-mysqlparameter-size::  Size Property
* connector-net-ref-mysqlclient-mysqlparameter-sourcecolumn::  SourceColumn Property
* connector-net-ref-mysqlclient-mysqlparameter-sourceversion::  SourceVersion Property
* connector-net-ref-mysqlclient-mysqlparameter-tostring::  `MySqlParameter.ToString' Method

*Note MySqlParameter overview:
connector-net-ref-mysqlclient-mysqlparameter.

*Public Instance Constructors*

*Note MySqlParameter:                Overloaded. Initializes a new
connector-net-ref-mysqlclient-mysqlparameterconstructor.instance of the MySqlParameter
                                     class.

*Public Instance Properties*

*Note DbType:                        Gets or sets the DbTypeof the
connector-net-ref-mysqlclient-mysqlparameter-dbtype.parameter.
*Note Direction:                     Gets or sets a value indicating
connector-net-ref-mysqlclient-mysqlparameter-direction.whether the parameter is input-only,
                                     output-only, bidirectional, or a
                                     stored procedure return value
                                     parameter. As of MySQL version 4.1
                                     and earlier, input-only is the only
                                     valid choice.
*Note IsNullable:                    Gets or sets a value indicating
connector-net-ref-mysqlclient-mysqlparameter-isnullable.whether the parameter accepts null
                                     values.
*Note IsUnsigned:                    
connector-net-ref-mysqlclient-mysqlparameter-isunsigned.
*Note MySqlDbType:                   Gets or sets the MySqlDbType of the
connector-net-ref-mysqlclient-mysqlparameter-mysqldbtype.parameter.
*Note ParameterName:                 Gets or sets the name of the
connector-net-ref-mysqlclient-mysqlparameter-parametername.MySqlParameter.
*Note Precision:                     Gets or sets the maximum number of
connector-net-ref-mysqlclient-mysqlparameter-precision.digits used to represent the *Note
                                     Value:
                                     connector-net-ref-mysqlclient-mysqlparameter-value.
                                     property.
*Note Scale:                         Gets or sets the number of decimal
connector-net-ref-mysqlclient-mysqlparameter-scale.places to which *Note Value:
                                     connector-net-ref-mysqlclient-mysqlparameter-value.
                                     is resolved.
*Note Size:                          Gets or sets the maximum size, in
connector-net-ref-mysqlclient-mysqlparameter-size.bytes, of the data within the
                                     column.
*Note SourceColumn:                  Gets or sets the name of the source
connector-net-ref-mysqlclient-mysqlparameter-sourcecolumn.column that is mapped to the
                                     DataSetand used for loading or
                                     returning the *Note Value:
                                     connector-net-ref-mysqlclient-mysqlparameter-value
                                     .
*Note SourceVersion:                 Gets or sets the DataRowVersionto
connector-net-ref-mysqlclient-mysqlparameter-sourceversion.use when loading *Note Value:
                                     connector-net-ref-mysqlclient-mysqlparameter-value
                                     .
*Note Value:                         Gets or sets the value of the
connector-net-ref-mysqlclient-mysqlparameter-value.parameter.

*Public Instance Methods*

CreateObjRef(inherited from          Creates an object that contains all
MarshalByRefObject)                  the relevant information required to
                                     generate a proxy used to
                                     communicate with a remote object.
Equals(inherited from Object)        Determines whether the specified
                                     Objectis equal to the current
                                     Object.
GetHashCode(inherited from Object)   Serves as a hash function for a
                                     particular type. GetHashCodeis
                                     suitable for use in hashing
                                     algorithms and data structures like
                                     a hash table.
GetLifetimeService(inherited from    Retrieves the current lifetime
MarshalByRefObject)                  service object that controls the
                                     lifetime policy for this instance.
GetType(inherited from Object)       Gets the Typeof the current
                                     instance.
InitializeLifetimeService(inherited  Obtains a lifetime service object
from MarshalByRefObject)             to control the lifetime policy for
                                     this instance.
*Note ToString:                      Overridden. Gets a string
connector-net-ref-mysqlclient-mysqlparameter-tostring.containing the *Note ParameterName:
                                     connector-net-ref-mysqlclient-mysqlparameter-parametername
                                     .

*See Also*

*Note MySqlParameter Class:
connector-net-ref-mysqlclient-mysqlparameter, *Note
MySql.Data.MySqlClient Namespace: connector-net-ref-mysqlclient.


File: manual.info,  Node: connector-net-ref-mysqlclient-mysqlparameterconstructor,  Next: connector-net-ref-mysqlclient-mysqlparameter-dbtype,  Prev: connector-net-ref-mysqlclient-mysqlparametermembers,  Up: connector-net-ref-mysqlclient-mysqlparametermembers

20.2.7.63 `MySqlParameter' Constructor
......................................

* Menu:

* connector-net-ref-mysqlclient-mysqlparameterconstructor1::  `MySqlParameter' Constructor ()
* connector-net-ref-mysqlclient-mysqlparameterconstructor3::  `MySqlParameter' Constructor
* connector-net-ref-mysqlclient-mysqlparameterconstructor4::  `MySqlParameter' Constructor (String, MySqlDbType, Int32)
* connector-net-ref-mysqlclient-mysqlparameterconstructor6::  `MySqlParameter' Constructor
* connector-net-ref-mysqlclient-mysqlparameterconstructor5::  `MySqlParameter' Constructor
* connector-net-ref-mysqlclient-mysqlparameterconstructor2::  `MySqlParameter' Constructor

Initializes a new instance of the MySqlParameter class.

*Overload List*

Initializes a new instance of the MySqlParameter class.

   * *Note public MySqlParameter();:
     connector-net-ref-mysqlclient-mysqlparameterconstructor1.

Initializes a new instance of the *Note MySqlParameter:
connector-net-ref-mysqlclient-mysqlparameter.  class with the parameter
name and the data type.

   * *Note public MySqlParameter(string:
     (MySqlDbType);)connector-net-ref-mysqlclient-mysqlparameterconstructor3.

Initializes a new instance of the *Note MySqlParameter:
connector-net-ref-mysqlclient-mysqlparameter.  class with the parameter
name, the *Note MySqlDbType: connector-net-ref-mysqlclient-mysqldbtype
, and the size.

   * *Note public MySqlParameter(string:
     (MySqlDbType)connector-net-ref-mysqlclient-mysqlparameterconstructor4.

Initializes a new instance of the *Note MySqlParameter:
connector-net-ref-mysqlclient-mysqlparameter.  class with the parameter
name, the type of the parameter, the size of the parameter, a
ParameterDirection, the precision of the parameter, the scale of the
parameter, the source column, a DataRowVersionto use, and the value of
the parameter.

   * *Note public MySqlParameter(string:
     (MySqlDbType)connector-net-ref-mysqlclient-mysqlparameterconstructor6.ParameterDirection,bool,byte,byte,string,DataRowVersion,object);

Initializes a new instance of the *Note MySqlParameter:
connector-net-ref-mysqlclient-mysqlparameter.  class with the parameter
name, the *Note MySqlDbType: connector-net-ref-mysqlclient-mysqldbtype
, the size, and the source column name.

   * *Note public MySqlParameter(string:
     (MySqlDbType)connector-net-ref-mysqlclient-mysqlparameterconstructor5.string);

Initializes a new instance of the *Note MySqlParameter:
connector-net-ref-mysqlclient-mysqlparameter.  class with the parameter
name and a value of the new MySqlParameter.

   * *Note public MySqlParameter(string:
     (object);)connector-net-ref-mysqlclient-mysqlparameterconstructor2.

*See Also*

*Note MySqlParameter Class:
connector-net-ref-mysqlclient-mysqlparameter, *Note
MySql.Data.MySqlClient Namespace: connector-net-ref-mysqlclient.


File: manual.info,  Node: connector-net-ref-mysqlclient-mysqlparameterconstructor1,  Next: connector-net-ref-mysqlclient-mysqlparameterconstructor3,  Prev: connector-net-ref-mysqlclient-mysqlparameterconstructor,  Up: connector-net-ref-mysqlclient-mysqlparameterconstructor

20.2.7.64 `MySqlParameter' Constructor ()
.........................................

Initializes a new instance of the MySqlParameter class.

*Syntax: Visual Basic*

     Overloads Public Sub New()

*Syntax: C#*

     public MySqlParameter();

*See Also*

*Note MySqlParameter Class:
connector-net-ref-mysqlclient-mysqlparameter, *Note
MySql.Data.MySqlClient Namespace: connector-net-ref-mysqlclient, *Note
MySqlParameter Constructor Overload List:
connector-net-ref-mysqlclient-mysqlparameterconstructor.


File: manual.info,  Node: connector-net-ref-mysqlclient-mysqlparameterconstructor3,  Next: connector-net-ref-mysqlclient-mysqlparameterconstructor4,  Prev: connector-net-ref-mysqlclient-mysqlparameterconstructor1,  Up: connector-net-ref-mysqlclient-mysqlparameterconstructor

20.2.7.65 `MySqlParameter' Constructor
......................................

* Menu:

* connector-net-ref-mysqlclient-mysqldbtype::  `MySqlDbType' Enumeration

Initializes a new instance of the *Note MySqlParameter:
connector-net-ref-mysqlclient-mysqlparameter.  class with the parameter
name and the data type.

*Syntax: Visual Basic*

     Overloads Public Sub New( _
        ByVal parameterName As String, _
        ByVal dbType As MySqlDbType _
     )

*Syntax: C#*

     public MySqlParameter(
     stringparameterName,
     MySqlDbTypedbType
     );

*Parameters*

   * `parameterName': The name of the parameter to map.

   * `dbType': One of the *Note MySqlDbType:
     connector-net-ref-mysqlclient-mysqldbtype.  values.

*See Also*

*Note MySqlParameter Class:
connector-net-ref-mysqlclient-mysqlparameter, *Note
MySql.Data.MySqlClient Namespace: connector-net-ref-mysqlclient, *Note
MySqlParameter Constructor Overload List:
connector-net-ref-mysqlclient-mysqlparameterconstructor.


File: manual.info,  Node: connector-net-ref-mysqlclient-mysqldbtype,  Prev: connector-net-ref-mysqlclient-mysqlparameterconstructor3,  Up: connector-net-ref-mysqlclient-mysqlparameterconstructor3

20.2.7.66 `MySqlDbType' Enumeration
...................................

Specifies MySQL specific data type of a field, property, for use in a
*Note MySqlParameter: connector-net-ref-mysqlclient-mysqlparameter .

*Syntax: Visual Basic*

     Public Enum MySqlDbType

*Syntax: C#*

     public enum MySqlDbType

*Members*

*Member Name*                        *Description*
Newdate                              Obsolete. Use Datetime or Date type.
Timestamp                            A timestamp. The range is
                                     '1970-01-01 00:00:01' to sometime
                                     in the year 2038.
Time                                 The range is '-838:59:59' to
                                     '838:59:59'
Date                                 Date The supported range is
                                     '1000-01-01' to '9999-12-31'
Datetime                             The supported range is '1000-01-01
                                     00:00:00' to '9999-12-31 23:59:59'
Year                                 A year in 2- or 4-digit format
                                     (default is 4-digit). The allowable
                                     values are 1901 to 2155, 0000 in the
                                     4-digit year format, and 1970-2069
                                     if you use the 2-digit format
                                     (70-69).
TinyBlob                             A BLOB column with a maximum length
                                     of 255 (2^8 - 1) characters
Blob                                 A BLOB column with a maximum length
                                     of 65535 (2^16 - 1) characters
MediumBlob                           A BLOB column with a maximum length
                                     of 16777215 (2^24 - 1) characters
LongBlob                             A BLOB column with a maximum length
                                     of 4294967295 or 4G (2^32 - 1)
                                     characters
Int16                                A 16-bit signed integer. The signed
                                     range is -32768 to 32767.  The
                                     unsigned range is 0 to 65535
Int24                                Specifies a 24 (3 byte) signed or
                                     unsigned value
Int32                                A 32-bit signed integer
Int64                                A 64-bit signed integer
Byte                                 The signed range is -128 to 127.
                                     The unsigned range is 0 to 255.
Float                                A small (single-precision)
                                     floating-point number. Allowable
                                     values are -3.402823466E+38 to
                                     -1.175494351E-38, 0, and
                                     1.175494351E-38 to 3.402823466E+38.
Double                               A normal-size (double-precision)
                                     floating-point number. Allowable
                                     values are -1.7976931348623157E+308
                                     to -2.2250738585072014E-308, 0, and
                                     2.2250738585072014E-308 to
                                     1.7976931348623157E+308.
UByte                                An 8-bit unsigned value
UInt16                               A 16-bit unsigned value
UInt24                               A 24-bit unsigned value
UInt32                               A 32-bit unsigned value
UInt64                               A 64-bit unsigned value
Decimal                              A fixed precision and scale numeric
                                     value between -1038 -1 and 10 38 -1
NewDecimal                           New Decimal
Set                                  A set. A string object that can
                                     have zero or more values, each of
                                     which must be chosen from the list
                                     of values 'value1', 'value2', ... A
                                     SET can have a maximum of 64
                                     members.
String                               Obsolete Use VarChar type
VarChar                              A variable-length string containing
                                     0 to 255 characters
VarString                            A variable-length string containing
                                     0 to 65535 characters
Enum                                 An enumeration. A string object
                                     that can have only one value, chosen
                                     from the list of values 'value1',
                                     'value2', ..., NULL or the special
                                     "" error value. An ENUM can have a
                                     maximum of 65535 distinct values.
Geometry                             
Bit                                  Bit-field data type
TinyText                             A nonbinary string column
                                     supporting a maximum length of 255
                                     (2^8 - 1) characters
Text                                 A nonbinary string column
                                     supporting a maximum length of
                                     65535 (2^16 - 1) characters
MediumText                           A nonbinary string column
                                     supporting a maximum length of
                                     16777215 (2^24 - 1) characters
LongText                             A nonbinary string column
                                     supporting a maximum length of
                                     4294967295 (2^32 - 1) characters

*Requirements*

Namespace: *Note MySql.Data.MySqlClient: connector-net-ref-mysqlclient.

Assembly: MySql.Data (in MySql.Data.dll)

*See Also*

*Note MySql.Data.MySqlClient Namespace: connector-net-ref-mysqlclient.


File: manual.info,  Node: connector-net-ref-mysqlclient-mysqlparameterconstructor4,  Next: connector-net-ref-mysqlclient-mysqlparameterconstructor6,  Prev: connector-net-ref-mysqlclient-mysqlparameterconstructor3,  Up: connector-net-ref-mysqlclient-mysqlparameterconstructor

20.2.7.67 `MySqlParameter' Constructor (String, MySqlDbType, Int32)
...................................................................

Initializes a new instance of the *Note MySqlParameter:
connector-net-ref-mysqlclient-mysqlparameter.  class with the parameter
name, the *Note MySqlDbType: connector-net-ref-mysqlclient-mysqldbtype
, and the size.

*Syntax: Visual Basic*

     Overloads Public Sub New( _
        ByVal parameterName As String, _
        ByVal dbType As MySqlDbType, _
        ByVal size As Integer _
     )

*Syntax: C#*

     public MySqlParameter(
     stringparameterName,
     MySqlDbTypedbType,
     intsize
     );

*Parameters*

   * `parameterName': The name of the parameter to map.

   * `dbType': One of the *Note MySqlDbType:
     connector-net-ref-mysqlclient-mysqldbtype.  values.

   * `size': The length of the parameter.

*See Also*

*Note MySqlParameter Class:
connector-net-ref-mysqlclient-mysqlparameter, *Note
MySql.Data.MySqlClient Namespace: connector-net-ref-mysqlclient, *Note
MySqlParameter Constructor Overload List:
connector-net-ref-mysqlclient-mysqlparameterconstructor.


File: manual.info,  Node: connector-net-ref-mysqlclient-mysqlparameterconstructor6,  Next: connector-net-ref-mysqlclient-mysqlparameterconstructor5,  Prev: connector-net-ref-mysqlclient-mysqlparameterconstructor4,  Up: connector-net-ref-mysqlclient-mysqlparameterconstructor

20.2.7.68 `MySqlParameter' Constructor
......................................

* Menu:

* connector-net-ref-mysqlclient-mysqlparameter-value::  Value Property

Initializes a new instance of the *Note MySqlParameter:
connector-net-ref-mysqlclient-mysqlparameter.  class with the parameter
name, the type of the parameter, the size of the parameter, a
ParameterDirection, the precision of the parameter, the scale of the
parameter, the source column, a DataRowVersionto use, and the value of
the parameter.

*Syntax: Visual Basic*

     Overloads Public Sub New( _
        ByVal parameterName As String, _
        ByVal dbType As MySqlDbType, _
        ByVal size As Integer, _
        ByVal direction As ParameterDirection, _
        ByVal isNullable As Boolean, _
        ByVal precision As Byte, _
        ByVal scale As Byte, _
        ByVal sourceColumn As String, _
        ByVal sourceVersion As DataRowVersion, _
        ByVal value As Object _
     )

*Syntax: C#*

     public MySqlParameter(
     stringparameterName,
     MySqlDbTypedbType,
     intsize,
     ParameterDirectiondirection,
     boolisNullable,
     byteprecision,
     bytescale,
     stringsourceColumn,
     DataRowVersionsourceVersion,
     objectvalue
     );

*Parameters*

   * `parameterName': The name of the parameter to map.

   * `dbType': One of the *Note MySqlDbType:
     connector-net-ref-mysqlclient-mysqldbtype.  values.

   * `size': The length of the parameter.

   * `direction': One of the ParameterDirectionvalues.

   * `isNullable': true if the value of the field can be null, otherwise
     false.

   * `precision': The total number of digits to the left and right of
     the decimal point to which *Note Value:
     connector-net-ref-mysqlclient-mysqlparameter-value.  is resolved.

   * `scale': The total number of decimal places to which *Note Value:
     connector-net-ref-mysqlclient-mysqlparameter-value.  is resolved.

   * `sourceColumn': The name of the source column.

   * `sourceVersion': One of the DataRowVersionvalues.

   * `value': An Objectthat is the value of the *Note MySqlParameter:
     connector-net-ref-mysqlclient-mysqlparameter .

*Exceptions*

*Exception Type*                     *Condition*
ArgumentException                    

*See Also*

*Note MySqlParameter Class:
connector-net-ref-mysqlclient-mysqlparameter, *Note
MySql.Data.MySqlClient Namespace: connector-net-ref-mysqlclient, *Note
MySqlParameter Constructor Overload List:
connector-net-ref-mysqlclient-mysqlparameterconstructor.


File: manual.info,  Node: connector-net-ref-mysqlclient-mysqlparameter-value,  Prev: connector-net-ref-mysqlclient-mysqlparameterconstructor6,  Up: connector-net-ref-mysqlclient-mysqlparameterconstructor6

20.2.7.69 Value Property
........................

Gets or sets the value of the parameter.

*Syntax: Visual Basic*

     NotOverridable Public Property Value As Object _
     _
       Implements IDataParameter.Value

*Syntax: C#*

     public object Value {get; set;}

*Implements*

IDataParameter.Value

*See Also*

*Note MySqlParameter Class:
connector-net-ref-mysqlclient-mysqlparameter, *Note
MySql.Data.MySqlClient Namespace: connector-net-ref-mysqlclient.


File: manual.info,  Node: connector-net-ref-mysqlclient-mysqlparameterconstructor5,  Next: connector-net-ref-mysqlclient-mysqlparameterconstructor2,  Prev: connector-net-ref-mysqlclient-mysqlparameterconstructor6,  Up: connector-net-ref-mysqlclient-mysqlparameterconstructor

20.2.7.70 `MySqlParameter' Constructor
......................................

Initializes a new instance of the *Note MySqlParameter:
connector-net-ref-mysqlclient-mysqlparameter.  class with the parameter
name, the *Note MySqlDbType: connector-net-ref-mysqlclient-mysqldbtype
, the size, and the source column name.

*Syntax: Visual Basic*

     Overloads Public Sub New( _
        ByVal parameterName As String, _
        ByVal dbType As MySqlDbType, _
        ByVal size As Integer, _
        ByVal sourceColumn As String _
     )

*Syntax: C#*

     public MySqlParameter(
     stringparameterName,
     MySqlDbTypedbType,
     intsize,
     stringsourceColumn
     );

*Parameters*

   * `parameterName': The name of the parameter to map.

   * `dbType': One of the *Note MySqlDbType:
     connector-net-ref-mysqlclient-mysqldbtype.  values.

   * `size': The length of the parameter.

   * `sourceColumn': The name of the source column.

*See Also*

*Note MySqlParameter Class:
connector-net-ref-mysqlclient-mysqlparameter, *Note
MySql.Data.MySqlClient Namespace: connector-net-ref-mysqlclient, *Note
MySqlParameter Constructor Overload List:
connector-net-ref-mysqlclient-mysqlparameterconstructor.


File: manual.info,  Node: connector-net-ref-mysqlclient-mysqlparameterconstructor2,  Prev: connector-net-ref-mysqlclient-mysqlparameterconstructor5,  Up: connector-net-ref-mysqlclient-mysqlparameterconstructor

20.2.7.71 `MySqlParameter' Constructor
......................................

Initializes a new instance of the *Note MySqlParameter:
connector-net-ref-mysqlclient-mysqlparameter.  class with the parameter
name and a value of the new MySqlParameter.

*Syntax: Visual Basic*

     Overloads Public Sub New( _
        ByVal parameterName As String, _
        ByVal value As Object _
     )

*Syntax: C#*

     public MySqlParameter(
     stringparameterName,
     objectvalue
     );

*Parameters*

   * `parameterName': The name of the parameter to map.

   * `value': An Objectthat is the value of the *Note MySqlParameter:
     connector-net-ref-mysqlclient-mysqlparameter .

*See Also*

*Note MySqlParameter Class:
connector-net-ref-mysqlclient-mysqlparameter, *Note
MySql.Data.MySqlClient Namespace: connector-net-ref-mysqlclient, *Note
MySqlParameter Constructor Overload List:
connector-net-ref-mysqlclient-mysqlparameterconstructor.


File: manual.info,  Node: connector-net-ref-mysqlclient-mysqlparameter-dbtype,  Next: connector-net-ref-mysqlclient-mysqlparameter-direction,  Prev: connector-net-ref-mysqlclient-mysqlparameterconstructor,  Up: connector-net-ref-mysqlclient-mysqlparametermembers

20.2.7.72 DbType Property
.........................

Gets or sets the DbTypeof the parameter.

*Syntax: Visual Basic*

     NotOverridable Public Property DbType As DbType _
     _
       Implements IDataParameter.DbType

*Syntax: C#*

     public System.Data.DbType DbType {get; set;}

*Implements*

IDataParameter.DbType

*See Also*

*Note MySqlParameter Class:
connector-net-ref-mysqlclient-mysqlparameter, *Note
MySql.Data.MySqlClient Namespace: connector-net-ref-mysqlclient.


File: manual.info,  Node: connector-net-ref-mysqlclient-mysqlparameter-direction,  Next: connector-net-ref-mysqlclient-mysqlparameter-isnullable,  Prev: connector-net-ref-mysqlclient-mysqlparameter-dbtype,  Up: connector-net-ref-mysqlclient-mysqlparametermembers

20.2.7.73 Direction Property
............................

Gets or sets a value indicating whether the parameter is input-only,
output-only, bidirectional, or a stored procedure return value
parameter. As of MySQL version 4.1 and earlier, input-only is the only
valid choice.

*Syntax: Visual Basic*

     NotOverridable Public Property Direction As ParameterDirection _
     _
       Implements IDataParameter.Direction

*Syntax: C#*

     public System.Data.ParameterDirection Direction {get; set;}

*Implements*

IDataParameter.Direction

*See Also*

*Note MySqlParameter Class:
connector-net-ref-mysqlclient-mysqlparameter, *Note
MySql.Data.MySqlClient Namespace: connector-net-ref-mysqlclient.


File: manual.info,  Node: connector-net-ref-mysqlclient-mysqlparameter-isnullable,  Next: connector-net-ref-mysqlclient-mysqlparameter-isunsigned,  Prev: connector-net-ref-mysqlclient-mysqlparameter-direction,  Up: connector-net-ref-mysqlclient-mysqlparametermembers

20.2.7.74 IsNullable Property
.............................

Gets or sets a value indicating whether the parameter accepts null
values.

*Syntax: Visual Basic*

     NotOverridable Public Property IsNullable As Boolean _
     _
       Implements IDataParameter.IsNullable

*Syntax: C#*

     public bool IsNullable {get; set;}

*Implements*

IDataParameter.IsNullable

*See Also*

*Note MySqlParameter Class:
connector-net-ref-mysqlclient-mysqlparameter, *Note
MySql.Data.MySqlClient Namespace: connector-net-ref-mysqlclient.


File: manual.info,  Node: connector-net-ref-mysqlclient-mysqlparameter-isunsigned,  Next: connector-net-ref-mysqlclient-mysqlparameter-mysqldbtype,  Prev: connector-net-ref-mysqlclient-mysqlparameter-isnullable,  Up: connector-net-ref-mysqlclient-mysqlparametermembers

20.2.7.75 IsUnsigned Property
.............................

*Syntax: Visual Basic*

     Public Property IsUnsigned As Boolean

*Syntax: C#*

     public bool IsUnsigned {get; set;}

*See Also*

*Note MySqlParameter Class:
connector-net-ref-mysqlclient-mysqlparameter, *Note
MySql.Data.MySqlClient Namespace: connector-net-ref-mysqlclient.


File: manual.info,  Node: connector-net-ref-mysqlclient-mysqlparameter-mysqldbtype,  Next: connector-net-ref-mysqlclient-mysqlparameter-parametername,  Prev: connector-net-ref-mysqlclient-mysqlparameter-isunsigned,  Up: connector-net-ref-mysqlclient-mysqlparametermembers

20.2.7.76 `MySqlDbType' Property
................................

Gets or sets the MySqlDbType of the parameter.

*Syntax: Visual Basic*

     Public Property MySqlDbType As MySqlDbType

*Syntax: C#*

     public MySqlDbType MySqlDbType {get; set;}

*See Also*

*Note MySqlParameter Class:
connector-net-ref-mysqlclient-mysqlparameter, *Note
MySql.Data.MySqlClient Namespace: connector-net-ref-mysqlclient.


File: manual.info,  Node: connector-net-ref-mysqlclient-mysqlparameter-parametername,  Next: connector-net-ref-mysqlclient-mysqlparameter-precision,  Prev: connector-net-ref-mysqlclient-mysqlparameter-mysqldbtype,  Up: connector-net-ref-mysqlclient-mysqlparametermembers

20.2.7.77 ParameterName Property
................................

Gets or sets the name of the MySqlParameter.

*Syntax: Visual Basic*

     NotOverridable Public Property ParameterName As String _
     _
       Implements IDataParameter.ParameterName

*Syntax: C#*

     public string ParameterName {get; set;}

*Implements*

IDataParameter.ParameterName

*See Also*

*Note MySqlParameter Class:
connector-net-ref-mysqlclient-mysqlparameter, *Note
MySql.Data.MySqlClient Namespace: connector-net-ref-mysqlclient.


File: manual.info,  Node: connector-net-ref-mysqlclient-mysqlparameter-precision,  Next: connector-net-ref-mysqlclient-mysqlparameter-scale,  Prev: connector-net-ref-mysqlclient-mysqlparameter-parametername,  Up: connector-net-ref-mysqlclient-mysqlparametermembers

20.2.7.78 Precision Property
............................

Gets or sets the maximum number of digits used to represent the *Note
Value: connector-net-ref-mysqlclient-mysqlparameter-value.  property.

*Syntax: Visual Basic*

     NotOverridable Public Property Precision As Byte _
     _
       Implements IDbDataParameter.Precision

*Syntax: C#*

     public byte Precision {get; set;}

*Implements*

IDbDataParameter.Precision

*See Also*

*Note MySqlParameter Class:
connector-net-ref-mysqlclient-mysqlparameter, *Note
MySql.Data.MySqlClient Namespace: connector-net-ref-mysqlclient.


File: manual.info,  Node: connector-net-ref-mysqlclient-mysqlparameter-scale,  Next: connector-net-ref-mysqlclient-mysqlparameter-size,  Prev: connector-net-ref-mysqlclient-mysqlparameter-precision,  Up: connector-net-ref-mysqlclient-mysqlparametermembers

20.2.7.79 Scale Property
........................

Gets or sets the number of decimal places to which *Note Value:
connector-net-ref-mysqlclient-mysqlparameter-value.  is resolved.

*Syntax: Visual Basic*

     NotOverridable Public Property Scale As Byte _
     _
       Implements IDbDataParameter.Scale

*Syntax: C#*

     public byte Scale {get; set;}

*Implements*

IDbDataParameter.Scale

*See Also*

*Note MySqlParameter Class:
connector-net-ref-mysqlclient-mysqlparameter, *Note
MySql.Data.MySqlClient Namespace: connector-net-ref-mysqlclient.


File: manual.info,  Node: connector-net-ref-mysqlclient-mysqlparameter-size,  Next: connector-net-ref-mysqlclient-mysqlparameter-sourcecolumn,  Prev: connector-net-ref-mysqlclient-mysqlparameter-scale,  Up: connector-net-ref-mysqlclient-mysqlparametermembers

20.2.7.80 Size Property
.......................

Gets or sets the maximum size, in bytes, of the data within the column.

*Syntax: Visual Basic*

     NotOverridable Public Property Size As Integer _
     _
       Implements IDbDataParameter.Size

*Syntax: C#*

     public int Size {get; set;}

*Implements*

IDbDataParameter.Size

*See Also*

*Note MySqlParameter Class:
connector-net-ref-mysqlclient-mysqlparameter, *Note
MySql.Data.MySqlClient Namespace: connector-net-ref-mysqlclient.


File: manual.info,  Node: connector-net-ref-mysqlclient-mysqlparameter-sourcecolumn,  Next: connector-net-ref-mysqlclient-mysqlparameter-sourceversion,  Prev: connector-net-ref-mysqlclient-mysqlparameter-size,  Up: connector-net-ref-mysqlclient-mysqlparametermembers

20.2.7.81 SourceColumn Property
...............................

Gets or sets the name of the source column that is mapped to the
DataSetand used for loading or returning the *Note Value:
connector-net-ref-mysqlclient-mysqlparameter-value .

*Syntax: Visual Basic*

     NotOverridable Public Property SourceColumn As String _
     _
       Implements IDataParameter.SourceColumn

*Syntax: C#*

     public string SourceColumn {get; set;}

*Implements*

IDataParameter.SourceColumn

*See Also*

*Note MySqlParameter Class:
connector-net-ref-mysqlclient-mysqlparameter, *Note
MySql.Data.MySqlClient Namespace: connector-net-ref-mysqlclient.


File: manual.info,  Node: connector-net-ref-mysqlclient-mysqlparameter-sourceversion,  Next: connector-net-ref-mysqlclient-mysqlparameter-tostring,  Prev: connector-net-ref-mysqlclient-mysqlparameter-sourcecolumn,  Up: connector-net-ref-mysqlclient-mysqlparametermembers

20.2.7.82 SourceVersion Property
................................

Gets or sets the DataRowVersionto use when loading *Note Value:
connector-net-ref-mysqlclient-mysqlparameter-value .

*Syntax: Visual Basic*

     NotOverridable Public Property SourceVersion As DataRowVersion _
     _
       Implements IDataParameter.SourceVersion

*Syntax: C#*

     public System.Data.DataRowVersion SourceVersion {get; set;}

*Implements*

IDataParameter.SourceVersion

*See Also*

*Note MySqlParameter Class:
connector-net-ref-mysqlclient-mysqlparameter, *Note
MySql.Data.MySqlClient Namespace: connector-net-ref-mysqlclient.


File: manual.info,  Node: connector-net-ref-mysqlclient-mysqlparameter-tostring,  Prev: connector-net-ref-mysqlclient-mysqlparameter-sourceversion,  Up: connector-net-ref-mysqlclient-mysqlparametermembers

20.2.7.83 `MySqlParameter.ToString' Method
..........................................

Overridden. Gets a string containing the *Note ParameterName:
connector-net-ref-mysqlclient-mysqlparameter-parametername .

*Syntax: Visual Basic*

     Overrides Public Function ToString() As String

*Syntax: C#*

     public override string ToString();

*Return Value*

*See Also*

*Note MySqlParameter Class:
connector-net-ref-mysqlclient-mysqlparameter, *Note
MySql.Data.MySqlClient Namespace: connector-net-ref-mysqlclient.


File: manual.info,  Node: connector-net-ref-mysqlclient-mysqlparametercollection-item1,  Next: connector-net-ref-mysqlclient-mysqlparametercollection-item2,  Prev: connector-net-ref-mysqlclient-mysqlparameter,  Up: connector-net-ref-mysqlclient-mysqlparametercollectionitem

20.2.7.84 Item Property (Int32)
...............................

Gets the *Note MySqlParameter:
connector-net-ref-mysqlclient-mysqlparameter.  at the specified index.

*Syntax: Visual Basic*

     Overloads Public Default Property Item( _
        ByVal index As Integer _
     ) As MySqlParameter

*Syntax: C#*

     public MySqlParameter this[
     intindex
     ] {get; set;}

*See Also*

*Note MySqlParameterCollection Class:
connector-net-ref-mysqlclient-mysqlparametercollection, *Note
MySql.Data.MySqlClient Namespace: connector-net-ref-mysqlclient, *Note
MySqlParameterCollection.Item Overload List:
connector-net-ref-mysqlclient-mysqlparametercollectionitem.


File: manual.info,  Node: connector-net-ref-mysqlclient-mysqlparametercollection-item2,  Prev: connector-net-ref-mysqlclient-mysqlparametercollection-item1,  Up: connector-net-ref-mysqlclient-mysqlparametercollectionitem

20.2.7.85 Item Property (String)
................................

Gets the *Note MySqlParameter:
connector-net-ref-mysqlclient-mysqlparameter.  with the specified name.

*Syntax: Visual Basic*

     Overloads Public Default Property Item( _
        ByVal name As String _
     ) As MySqlParameter

*Syntax: C#*

     public MySqlParameter this[
     stringname
     ] {get; set;}

*See Also*

*Note MySqlParameterCollection Class:
connector-net-ref-mysqlclient-mysqlparametercollection, *Note
MySql.Data.MySqlClient Namespace: connector-net-ref-mysqlclient, *Note
MySqlParameterCollection.Item Overload List:
connector-net-ref-mysqlclient-mysqlparametercollectionitem.


File: manual.info,  Node: connector-net-ref-mysqlclient-mysqlparametercollection-add-overloads,  Next: connector-net-ref-mysqlclient-mysqlparametercollection-clear,  Prev: connector-net-ref-mysqlclient-mysqlparametercollectionitem,  Up: connector-net-ref-mysqlclient-mysqlparametercollectionmembers

20.2.7.86 Add Method
....................

* Menu:

* connector-net-ref-mysqlclient-mysqlparametercollection-add-overload-2::  `MySqlParameterCollection.Add' Method
* connector-net-ref-mysqlclient-mysqlparametercollection-add-overload-1::  `MySqlParameterCollection.Add' Method
* connector-net-ref-mysqlclient-mysqlparametercollection-add-overload-4::  `MySqlParameterCollection.Add' Method
* connector-net-ref-mysqlclient-mysqlparametercollection-add-overload-5::  `MySqlParameterCollection.Add' Method
* connector-net-ref-mysqlclient-mysqlparametercollection-add-overload-6::  `MySqlParameterCollection.Add' Method
* connector-net-ref-mysqlclient-mysqlparametercollection-add-overload-3::  `MySqlParameterCollection.Add' Method

Adds the specified *Note MySqlParameter:
connector-net-ref-mysqlclient-mysqlparameter.  object to the *Note
MySqlParameterCollection:
connector-net-ref-mysqlclient-mysqlparametercollection .

*Overload List*

Adds the specified *Note MySqlParameter:
connector-net-ref-mysqlclient-mysqlparameter.  object to the *Note
MySqlParameterCollection:
connector-net-ref-mysqlclient-mysqlparametercollection .

   * *Note public MySqlParameter Add(MySqlParameter);:
     connector-net-ref-mysqlclient-mysqlparametercollection-add-overload-2.

Adds the specified *Note MySqlParameter:
connector-net-ref-mysqlclient-mysqlparameter.  object to the *Note
MySqlParameterCollection:
connector-net-ref-mysqlclient-mysqlparametercollection .

   * *Note public int Add(object);:
     connector-net-ref-mysqlclient-mysqlparametercollection-add-overload-1.

Adds a *Note MySqlParameter:
connector-net-ref-mysqlclient-mysqlparameter.  to the *Note
MySqlParameterCollection:
connector-net-ref-mysqlclient-mysqlparametercollection.  given the
parameter name and the data type.

   * *Note public MySqlParameter Add(string:
     (MySqlDbType);)connector-net-ref-mysqlclient-mysqlparametercollection-add-overload-4.

Adds a *Note MySqlParameter:
connector-net-ref-mysqlclient-mysqlparameter.  to the *Note
MySqlParameterCollection:
connector-net-ref-mysqlclient-mysqlparametercollection.  with the
parameter name, the data type, and the column length.

   * *Note public MySqlParameter Add(string:
     (MySqlDbType)connector-net-ref-mysqlclient-mysqlparametercollection-add-overload-5.

Adds a *Note MySqlParameter:
connector-net-ref-mysqlclient-mysqlparameter.  to the *Note
MySqlParameterCollection:
connector-net-ref-mysqlclient-mysqlparametercollection.  with the
parameter name, the data type, the column length, and the source column
name.

   * *Note public MySqlParameter Add(string:
     (MySqlDbType)connector-net-ref-mysqlclient-mysqlparametercollection-add-overload-6.string);

Adds a *Note MySqlParameter:
connector-net-ref-mysqlclient-mysqlparameter.  to the *Note
MySqlParameterCollection:
connector-net-ref-mysqlclient-mysqlparametercollection.  given the
specified parameter name and value.

   * *Note public MySqlParameter Add(string:
     (object);)connector-net-ref-mysqlclient-mysqlparametercollection-add-overload-3.

*See Also*

*Note MySqlParameterCollection Class:
connector-net-ref-mysqlclient-mysqlparametercollection, *Note
MySql.Data.MySqlClient Namespace: connector-net-ref-mysqlclient.


File: manual.info,  Node: connector-net-ref-mysqlclient-mysqlparametercollection-add-overload-2,  Next: connector-net-ref-mysqlclient-mysqlparametercollection-add-overload-1,  Prev: connector-net-ref-mysqlclient-mysqlparametercollection-add-overloads,  Up: connector-net-ref-mysqlclient-mysqlparametercollection-add-overloads

20.2.7.87 `MySqlParameterCollection.Add' Method
...............................................

Adds the specified *Note MySqlParameter:
connector-net-ref-mysqlclient-mysqlparameter.  object to the *Note
MySqlParameterCollection:
connector-net-ref-mysqlclient-mysqlparametercollection .

*Syntax: Visual Basic*

     Overloads Public Function Add( _
        ByVal value As MySqlParameter _
     ) As MySqlParameter

*Syntax: C#*

     public MySqlParameter Add(
     MySqlParametervalue
     );

*Parameters*

   * `value': The *Note MySqlParameter:
     connector-net-ref-mysqlclient-mysqlparameter.  to add to the
     collection.

*Return Value*

The newly added *Note MySqlParameter:
connector-net-ref-mysqlclient-mysqlparameter.  object.

*See Also*

*Note MySqlParameterCollection Class:
connector-net-ref-mysqlclient-mysqlparametercollection, *Note
MySql.Data.MySqlClient Namespace: connector-net-ref-mysqlclient, *Note
MySqlParameterCollection.Add Overload List:
connector-net-ref-mysqlclient-mysqlparametercollection-add-overloads.


File: manual.info,  Node: connector-net-ref-mysqlclient-mysqlparametercollection-add-overload-1,  Next: connector-net-ref-mysqlclient-mysqlparametercollection-add-overload-4,  Prev: connector-net-ref-mysqlclient-mysqlparametercollection-add-overload-2,  Up: connector-net-ref-mysqlclient-mysqlparametercollection-add-overloads

20.2.7.88 `MySqlParameterCollection.Add' Method
...............................................

Adds the specified *Note MySqlParameter:
connector-net-ref-mysqlclient-mysqlparameter.  object to the *Note
MySqlParameterCollection:
connector-net-ref-mysqlclient-mysqlparametercollection .

*Syntax: Visual Basic*

     NotOverridable Overloads Public Function Add( _
        ByVal value As Object _
     ) As Integer _
     _
       Implements IList.Add

*Syntax: C#*

     public int Add(
     objectvalue
     );

*Parameters*

   * `value': The *Note MySqlParameter:
     connector-net-ref-mysqlclient-mysqlparameter.  to add to the
     collection.

*Return Value*

The index of the new *Note MySqlParameter:
connector-net-ref-mysqlclient-mysqlparameter.  object.

*Implements*

IList.Add

*See Also*

*Note MySqlParameterCollection Class:
connector-net-ref-mysqlclient-mysqlparametercollection, *Note
MySql.Data.MySqlClient Namespace: connector-net-ref-mysqlclient, *Note
MySqlParameterCollection.Add Overload List:
connector-net-ref-mysqlclient-mysqlparametercollection-add-overloads.


File: manual.info,  Node: connector-net-ref-mysqlclient-mysqlparametercollection-add-overload-4,  Next: connector-net-ref-mysqlclient-mysqlparametercollection-add-overload-5,  Prev: connector-net-ref-mysqlclient-mysqlparametercollection-add-overload-1,  Up: connector-net-ref-mysqlclient-mysqlparametercollection-add-overloads

20.2.7.89 `MySqlParameterCollection.Add' Method
...............................................

Adds a *Note MySqlParameter:
connector-net-ref-mysqlclient-mysqlparameter.  to the *Note
MySqlParameterCollection:
connector-net-ref-mysqlclient-mysqlparametercollection.  given the
parameter name and the data type.

*Syntax: Visual Basic*

     Overloads Public Function Add( _
        ByVal parameterName As String, _
        ByVal dbType As MySqlDbType _
     ) As MySqlParameter

*Syntax: C#*

     public MySqlParameter Add(
     stringparameterName,
     MySqlDbTypedbType
     );

*Parameters*

   * `parameterName': The name of the parameter.

   * `dbType': One of the *Note MySqlDbType:
     connector-net-ref-mysqlclient-mysqldbtype.  values.

*Return Value*

The newly added *Note MySqlParameter:
connector-net-ref-mysqlclient-mysqlparameter.  object.

*See Also*

*Note MySqlParameterCollection Class:
connector-net-ref-mysqlclient-mysqlparametercollection, *Note
MySql.Data.MySqlClient Namespace: connector-net-ref-mysqlclient, *Note
MySqlParameterCollection.Add Overload List:
connector-net-ref-mysqlclient-mysqlparametercollection-add-overloads.


File: manual.info,  Node: connector-net-ref-mysqlclient-mysqlparametercollection-add-overload-5,  Next: connector-net-ref-mysqlclient-mysqlparametercollection-add-overload-6,  Prev: connector-net-ref-mysqlclient-mysqlparametercollection-add-overload-4,  Up: connector-net-ref-mysqlclient-mysqlparametercollection-add-overloads

20.2.7.90 `MySqlParameterCollection.Add' Method
...............................................

Adds a *Note MySqlParameter:
connector-net-ref-mysqlclient-mysqlparameter.  to the *Note
MySqlParameterCollection:
connector-net-ref-mysqlclient-mysqlparametercollection.  with the
parameter name, the data type, and the column length.

*Syntax: Visual Basic*

     Overloads Public Function Add( _
        ByVal parameterName As String, _
        ByVal dbType As MySqlDbType, _
        ByVal size As Integer _
     ) As MySqlParameter

*Syntax: C#*

     public MySqlParameter Add(
     stringparameterName,
     MySqlDbTypedbType,
     intsize
     );

*Parameters*

   * `parameterName': The name of the parameter.

   * `dbType': One of the *Note MySqlDbType:
     connector-net-ref-mysqlclient-mysqldbtype.  values.

   * `size': The length of the column.

*Return Value*

The newly added *Note MySqlParameter:
connector-net-ref-mysqlclient-mysqlparameter.  object.

*See Also*

*Note MySqlParameterCollection Class:
connector-net-ref-mysqlclient-mysqlparametercollection, *Note
MySql.Data.MySqlClient Namespace: connector-net-ref-mysqlclient, *Note
MySqlParameterCollection.Add Overload List:
connector-net-ref-mysqlclient-mysqlparametercollection-add-overloads.


File: manual.info,  Node: connector-net-ref-mysqlclient-mysqlparametercollection-add-overload-6,  Next: connector-net-ref-mysqlclient-mysqlparametercollection-add-overload-3,  Prev: connector-net-ref-mysqlclient-mysqlparametercollection-add-overload-5,  Up: connector-net-ref-mysqlclient-mysqlparametercollection-add-overloads

20.2.7.91 `MySqlParameterCollection.Add' Method
...............................................

Adds a *Note MySqlParameter:
connector-net-ref-mysqlclient-mysqlparameter.  to the *Note
MySqlParameterCollection:
connector-net-ref-mysqlclient-mysqlparametercollection.  with the
parameter name, the data type, the column length, and the source column
name.

*Syntax: Visual Basic*

     Overloads Public Function Add( _
        ByVal parameterName As String, _
        ByVal dbType As MySqlDbType, _
        ByVal size As Integer, _
        ByVal sourceColumn As String _
     ) As MySqlParameter

*Syntax: C#*

     public MySqlParameter Add(
     stringparameterName,
     MySqlDbTypedbType,
     intsize,
     stringsourceColumn
     );

*Parameters*

   * `parameterName': The name of the parameter.

   * `dbType': One of the *Note MySqlDbType:
     connector-net-ref-mysqlclient-mysqldbtype.  values.

   * `size': The length of the column.

   * `sourceColumn': The name of the source column.

*Return Value*

The newly added *Note MySqlParameter:
connector-net-ref-mysqlclient-mysqlparameter.  object.

*See Also*

*Note MySqlParameterCollection Class:
connector-net-ref-mysqlclient-mysqlparametercollection, *Note
MySql.Data.MySqlClient Namespace: connector-net-ref-mysqlclient, *Note
MySqlParameterCollection.Add Overload List:
connector-net-ref-mysqlclient-mysqlparametercollection-add-overloads.


File: manual.info,  Node: connector-net-ref-mysqlclient-mysqlparametercollection-add-overload-3,  Prev: connector-net-ref-mysqlclient-mysqlparametercollection-add-overload-6,  Up: connector-net-ref-mysqlclient-mysqlparametercollection-add-overloads

20.2.7.92 `MySqlParameterCollection.Add' Method
...............................................

Adds a *Note MySqlParameter:
connector-net-ref-mysqlclient-mysqlparameter.  to the *Note
MySqlParameterCollection:
connector-net-ref-mysqlclient-mysqlparametercollection.  given the
specified parameter name and value.

*Syntax: Visual Basic*

     Overloads Public Function Add( _
        ByVal parameterName As String, _
        ByVal value As Object _
     ) As MySqlParameter

*Syntax: C#*

     public MySqlParameter Add(
     stringparameterName,
     objectvalue
     );

*Parameters*

   * `parameterName': The name of the parameter.

   * `value': The *Note Value:
     connector-net-ref-mysqlclient-mysqlparameter-value.  of the *Note
     MySqlParameter: connector-net-ref-mysqlclient-mysqlparameter.  to
     add to the collection.

*Return Value*

The newly added *Note MySqlParameter:
connector-net-ref-mysqlclient-mysqlparameter.  object.

*See Also*

*Note MySqlParameterCollection Class:
connector-net-ref-mysqlclient-mysqlparametercollection, *Note
MySql.Data.MySqlClient Namespace: connector-net-ref-mysqlclient, *Note
MySqlParameterCollection.Add Overload List:
connector-net-ref-mysqlclient-mysqlparametercollection-add-overloads.


File: manual.info,  Node: connector-net-ref-mysqlclient-mysqlparametercollection-clear,  Next: connector-net-ref-mysqlclient-mysqlparametercollection-contains-overloads,  Prev: connector-net-ref-mysqlclient-mysqlparametercollection-add-overloads,  Up: connector-net-ref-mysqlclient-mysqlparametercollectionmembers

20.2.7.93 `MySqlParameterCollection.Clear' Method
.................................................

Removes all items from the collection.

*Syntax: Visual Basic*

     NotOverridable Public Sub Clear() _
     _
       Implements IList.Clear

*Syntax: C#*

     public void Clear();

*Implements*

IList.Clear

*See Also*

*Note MySqlParameterCollection Class:
connector-net-ref-mysqlclient-mysqlparametercollection, *Note
MySql.Data.MySqlClient Namespace: connector-net-ref-mysqlclient.


File: manual.info,  Node: connector-net-ref-mysqlclient-mysqlparametercollection-contains-overloads,  Next: connector-net-ref-mysqlclient-mysqlparametercollection-copyto,  Prev: connector-net-ref-mysqlclient-mysqlparametercollection-clear,  Up: connector-net-ref-mysqlclient-mysqlparametercollectionmembers

20.2.7.94 Contains Method
.........................

* Menu:

* connector-net-ref-mysqlclient-mysqlparametercollection-contains-overload-1::  `MySqlParameterCollection.Contains' Method
* connector-net-ref-mysqlclient-mysqlparametercollection-contains-overload-2::  `MySqlParameterCollection.Contains' Method

Gets a value indicating whether a *Note MySqlParameter:
connector-net-ref-mysqlclient-mysqlparameter.  exists in the collection.

*Overload List*

Gets a value indicating whether a MySqlParameter exists in the
collection.

   * *Note public bool Contains(object);:
     connector-net-ref-mysqlclient-mysqlparametercollection-contains-overload-1.

Gets a value indicating whether a *Note MySqlParameter:
connector-net-ref-mysqlclient-mysqlparameter.  with the specified
parameter name exists in the collection.

   * *Note public bool Contains(string);:
     connector-net-ref-mysqlclient-mysqlparametercollection-contains-overload-2.

*See Also*

*Note MySqlParameterCollection Class:
connector-net-ref-mysqlclient-mysqlparametercollection, *Note
MySql.Data.MySqlClient Namespace: connector-net-ref-mysqlclient.


File: manual.info,  Node: connector-net-ref-mysqlclient-mysqlparametercollection-contains-overload-1,  Next: connector-net-ref-mysqlclient-mysqlparametercollection-contains-overload-2,  Prev: connector-net-ref-mysqlclient-mysqlparametercollection-contains-overloads,  Up: connector-net-ref-mysqlclient-mysqlparametercollection-contains-overloads

20.2.7.95 `MySqlParameterCollection.Contains' Method
....................................................

Gets a value indicating whether a MySqlParameter exists in the
collection.

*Syntax: Visual Basic*

     NotOverridable Overloads Public Function Contains( _
        ByVal value As Object _
     ) As Boolean _
     _
       Implements IList.Contains

*Syntax: C#*

     public bool Contains(
     objectvalue
     );

*Parameters*

   * `value': The value of the *Note MySqlParameter:
     connector-net-ref-mysqlclient-mysqlparameter.  object to find.

*Return Value*

true if the collection contains the *Note MySqlParameter:
connector-net-ref-mysqlclient-mysqlparameter.  object; otherwise, false.

*Implements*

IList.Contains

*See Also*

*Note MySqlParameterCollection Class:
connector-net-ref-mysqlclient-mysqlparametercollection, *Note
MySql.Data.MySqlClient Namespace: connector-net-ref-mysqlclient, *Note
MySqlParameterCollection.Contains Overload List:
connector-net-ref-mysqlclient-mysqlparametercollection-contains-overloads.


File: manual.info,  Node: connector-net-ref-mysqlclient-mysqlparametercollection-contains-overload-2,  Prev: connector-net-ref-mysqlclient-mysqlparametercollection-contains-overload-1,  Up: connector-net-ref-mysqlclient-mysqlparametercollection-contains-overloads

20.2.7.96 `MySqlParameterCollection.Contains' Method
....................................................

Gets a value indicating whether a *Note MySqlParameter:
connector-net-ref-mysqlclient-mysqlparameter.  with the specified
parameter name exists in the collection.

*Syntax: Visual Basic*

     NotOverridable Overloads Public Function Contains( _
        ByVal name As String _
     ) As Boolean _
     _
       Implements IDataParameterCollection.Contains

*Syntax: C#*

     public bool Contains(
     stringname
     );

*Parameters*

   * `name': The name of the *Note MySqlParameter:
     connector-net-ref-mysqlclient-mysqlparameter.  object to find.

*Return Value*

true if the collection contains the parameter; otherwise, false.

*Implements*

IDataParameterCollection.Contains

*See Also*

*Note MySqlParameterCollection Class:
connector-net-ref-mysqlclient-mysqlparametercollection, *Note
MySql.Data.MySqlClient Namespace: connector-net-ref-mysqlclient, *Note
MySqlParameterCollection.Contains Overload List:
connector-net-ref-mysqlclient-mysqlparametercollection-contains-overloads.


File: manual.info,  Node: connector-net-ref-mysqlclient-mysqlparametercollection-copyto,  Next: connector-net-ref-mysqlclient-mysqlparametercollection-indexof-overloads,  Prev: connector-net-ref-mysqlclient-mysqlparametercollection-contains-overloads,  Up: connector-net-ref-mysqlclient-mysqlparametercollectionmembers

20.2.7.97 `MySqlParameterCollection.CopyTo' Method
..................................................

Copies MySqlParameter objects from the MySqlParameterCollection to the
specified array.

*Syntax: Visual Basic*

     NotOverridable Public Sub CopyTo( _
        ByVal array As Array, _
        ByVal index As Integer _
     ) _
     _
       Implements ICollection.CopyTo

*Syntax: C#*

     public void CopyTo(
     Arrayarray,
     intindex
     );

*Parameters*

   * `array':

   * `index':

*Implements*

ICollection.CopyTo

*See Also*

*Note MySqlParameterCollection Class:
connector-net-ref-mysqlclient-mysqlparametercollection, *Note
MySql.Data.MySqlClient Namespace: connector-net-ref-mysqlclient.


File: manual.info,  Node: connector-net-ref-mysqlclient-mysqlparametercollection-indexof-overloads,  Next: connector-net-ref-mysqlclient-mysqlparametercollection-insert,  Prev: connector-net-ref-mysqlclient-mysqlparametercollection-copyto,  Up: connector-net-ref-mysqlclient-mysqlparametercollectionmembers

20.2.7.98 IndexOf Method
........................

* Menu:

* connector-net-ref-mysqlclient-mysqlparametercollection-indexof-overload-1::  `MySqlParameterCollection.IndexOf' Method
* connector-net-ref-mysqlclient-mysqlparametercollection-indexof-overload-2::  `MySqlParameterCollection.IndexOf' Method

Gets the location of a *Note MySqlParameter:
connector-net-ref-mysqlclient-mysqlparameter.  in the collection.

*Overload List*

Gets the location of a *Note MySqlParameter:
connector-net-ref-mysqlclient-mysqlparameter.  in the collection.

   * *Note public int IndexOf(object);:
     connector-net-ref-mysqlclient-mysqlparametercollection-indexof-overload-1.

Gets the location of the *Note MySqlParameter:
connector-net-ref-mysqlclient-mysqlparameter.  in the collection with a
specific parameter name.

   * *Note public int IndexOf(string);:
     connector-net-ref-mysqlclient-mysqlparametercollection-indexof-overload-2.

*See Also*

*Note MySqlParameterCollection Class:
connector-net-ref-mysqlclient-mysqlparametercollection, *Note
MySql.Data.MySqlClient Namespace: connector-net-ref-mysqlclient.


File: manual.info,  Node: connector-net-ref-mysqlclient-mysqlparametercollection-indexof-overload-1,  Next: connector-net-ref-mysqlclient-mysqlparametercollection-indexof-overload-2,  Prev: connector-net-ref-mysqlclient-mysqlparametercollection-indexof-overloads,  Up: connector-net-ref-mysqlclient-mysqlparametercollection-indexof-overloads

20.2.7.99 `MySqlParameterCollection.IndexOf' Method
...................................................

Gets the location of a *Note MySqlParameter:
connector-net-ref-mysqlclient-mysqlparameter.  in the collection.

*Syntax: Visual Basic*

     NotOverridable Overloads Public Function IndexOf( _
        ByVal value As Object _
     ) As Integer _
     _
       Implements IList.IndexOf

*Syntax: C#*

     public int IndexOf(
     objectvalue
     );

*Parameters*

   * `value': The *Note MySqlParameter:
     connector-net-ref-mysqlclient-mysqlparameter.  object to locate.

*Return Value*

The zero-based location of the *Note MySqlParameter:
connector-net-ref-mysqlclient-mysqlparameter.  in the collection.

*Implements*

IList.IndexOf

*See Also*

*Note MySqlParameterCollection Class:
connector-net-ref-mysqlclient-mysqlparametercollection, *Note
MySql.Data.MySqlClient Namespace: connector-net-ref-mysqlclient, *Note
MySqlParameterCollection.IndexOf Overload List:
connector-net-ref-mysqlclient-mysqlparametercollection-indexof-overloads.


File: manual.info,  Node: connector-net-ref-mysqlclient-mysqlparametercollection-indexof-overload-2,  Prev: connector-net-ref-mysqlclient-mysqlparametercollection-indexof-overload-1,  Up: connector-net-ref-mysqlclient-mysqlparametercollection-indexof-overloads

20.2.7.100 `MySqlParameterCollection.IndexOf' Method
....................................................

Gets the location of the *Note MySqlParameter:
connector-net-ref-mysqlclient-mysqlparameter.  in the collection with a
specific parameter name.

*Syntax: Visual Basic*

     NotOverridable Overloads Public Function IndexOf( _
        ByVal parameterName As String _
     ) As Integer _
     _
       Implements IDataParameterCollection.IndexOf

*Syntax: C#*

     public int IndexOf(
     stringparameterName
     );

*Parameters*

   * `parameterName': The name of the *Note MySqlParameter:
     connector-net-ref-mysqlclient-mysqlparameter.  object to retrieve.

*Return Value*

The zero-based location of the *Note MySqlParameter:
connector-net-ref-mysqlclient-mysqlparameter.  in the collection.

*Implements*

IDataParameterCollection.IndexOf

*See Also*

*Note MySqlParameterCollection Class:
connector-net-ref-mysqlclient-mysqlparametercollection, *Note
MySql.Data.MySqlClient Namespace: connector-net-ref-mysqlclient, *Note
MySqlParameterCollection.IndexOf Overload List:
connector-net-ref-mysqlclient-mysqlparametercollection-indexof-overloads.


File: manual.info,  Node: connector-net-ref-mysqlclient-mysqlparametercollection-insert,  Next: connector-net-ref-mysqlclient-mysqlparametercollection-remove,  Prev: connector-net-ref-mysqlclient-mysqlparametercollection-indexof-overloads,  Up: connector-net-ref-mysqlclient-mysqlparametercollectionmembers

20.2.7.101 `MySqlParameterCollection.Insert' Method
...................................................

Inserts a MySqlParameter into the collection at the specified index.

*Syntax: Visual Basic*

     NotOverridable Public Sub Insert( _
        ByVal index As Integer, _
        ByVal value As Object _
     ) _
     _
       Implements IList.Insert

*Syntax: C#*

     public void Insert(
     intindex,
     objectvalue
     );

*Parameters*

   * `index':

   * `value':

*Implements*

IList.Insert

*See Also*

*Note MySqlParameterCollection Class:
connector-net-ref-mysqlclient-mysqlparametercollection, *Note
MySql.Data.MySqlClient Namespace: connector-net-ref-mysqlclient.


File: manual.info,  Node: connector-net-ref-mysqlclient-mysqlparametercollection-remove,  Next: connector-net-ref-mysqlclient-mysqlparametercollection-removeat-overloads,  Prev: connector-net-ref-mysqlclient-mysqlparametercollection-insert,  Up: connector-net-ref-mysqlclient-mysqlparametercollectionmembers

20.2.7.102 `MySqlParameterCollection.Remove' Method
...................................................

Removes the specified MySqlParameter from the collection.

*Syntax: Visual Basic*

     NotOverridable Public Sub Remove( _
        ByVal value As Object _
     ) _
     _
       Implements IList.Remove

*Syntax: C#*

     public void Remove(
     objectvalue
     );

*Parameters*

   * `value':

*Implements*

IList.Remove

*See Also*

*Note MySqlParameterCollection Class:
connector-net-ref-mysqlclient-mysqlparametercollection, *Note
MySql.Data.MySqlClient Namespace: connector-net-ref-mysqlclient.


File: manual.info,  Node: connector-net-ref-mysqlclient-mysqlparametercollection-removeat-overloads,  Prev: connector-net-ref-mysqlclient-mysqlparametercollection-remove,  Up: connector-net-ref-mysqlclient-mysqlparametercollectionmembers

20.2.7.103 RemoveAt Method
..........................

* Menu:

* connector-net-ref-mysqlclient-mysqlparametercollection-removeat-overload-1::  `MySqlParameterCollection.RemoveAt' Method
* connector-net-ref-mysqlclient-mysqlparametercollection-removeat-overload-2::  `MySqlParameterCollection.RemoveAt' Method

Removes the specified *Note MySqlParameter:
connector-net-ref-mysqlclient-mysqlparameter.  from the collection.

*Overload List*

Removes the specified *Note MySqlParameter:
connector-net-ref-mysqlclient-mysqlparameter.  from the collection
using a specific index.

   * *Note public void RemoveAt(int);:
     connector-net-ref-mysqlclient-mysqlparametercollection-removeat-overload-1.

Removes the specified *Note MySqlParameter:
connector-net-ref-mysqlclient-mysqlparameter.  from the collection
using the parameter name.

   * *Note public void RemoveAt(string);:
     connector-net-ref-mysqlclient-mysqlparametercollection-removeat-overload-2.

*See Also*

*Note MySqlParameterCollection Class:
connector-net-ref-mysqlclient-mysqlparametercollection, *Note
MySql.Data.MySqlClient Namespace: connector-net-ref-mysqlclient.


File: manual.info,  Node: connector-net-ref-mysqlclient-mysqlparametercollection-removeat-overload-1,  Next: connector-net-ref-mysqlclient-mysqlparametercollection-removeat-overload-2,  Prev: connector-net-ref-mysqlclient-mysqlparametercollection-removeat-overloads,  Up: connector-net-ref-mysqlclient-mysqlparametercollection-removeat-overloads

20.2.7.104 `MySqlParameterCollection.RemoveAt' Method
.....................................................

Removes the specified *Note MySqlParameter:
connector-net-ref-mysqlclient-mysqlparameter.  from the collection
using a specific index.

*Syntax: Visual Basic*

     NotOverridable Overloads Public Sub RemoveAt( _
        ByVal index As Integer _
     ) _
     _
       Implements IList.RemoveAt

*Syntax: C#*

     public void RemoveAt(
     intindex
     );

*Parameters*

   * `index': The zero-based index of the parameter.

*Implements*

IList.RemoveAt

*See Also*

*Note MySqlParameterCollection Class:
connector-net-ref-mysqlclient-mysqlparametercollection, *Note
MySql.Data.MySqlClient Namespace: connector-net-ref-mysqlclient, *Note
MySqlParameterCollection.RemoveAt Overload List:
connector-net-ref-mysqlclient-mysqlparametercollection-removeat-overloads.


File: manual.info,  Node: connector-net-ref-mysqlclient-mysqlparametercollection-removeat-overload-2,  Prev: connector-net-ref-mysqlclient-mysqlparametercollection-removeat-overload-1,  Up: connector-net-ref-mysqlclient-mysqlparametercollection-removeat-overloads

20.2.7.105 `MySqlParameterCollection.RemoveAt' Method
.....................................................

Removes the specified *Note MySqlParameter:
connector-net-ref-mysqlclient-mysqlparameter.  from the collection
using the parameter name.

*Syntax: Visual Basic*

     NotOverridable Overloads Public Sub RemoveAt( _
        ByVal name As String _
     ) _
     _
       Implements IDataParameterCollection.RemoveAt

*Syntax: C#*

     public void RemoveAt(
     stringname
     );

*Parameters*

   * `name': The name of the *Note MySqlParameter:
     connector-net-ref-mysqlclient-mysqlparameter.  object to retrieve.

*Implements*

IDataParameterCollection.RemoveAt

*See Also*

*Note MySqlParameterCollection Class:
connector-net-ref-mysqlclient-mysqlparametercollection, *Note
MySql.Data.MySqlClient Namespace: connector-net-ref-mysqlclient, *Note
MySqlParameterCollection.RemoveAt Overload List:
connector-net-ref-mysqlclient-mysqlparametercollection-removeat-overloads.


File: manual.info,  Node: connector-net-ref-mysqlclient-mysqlcommand-transaction,  Next: connector-net-ref-mysqlclient-mysqlcommand-updatedrowsource,  Prev: connector-net-ref-mysqlclient-mysqlcommand-parameters,  Up: connector-net-ref-mysqlclient-mysqlcommandmembers

20.2.7.106 Transaction Property
...............................

*Syntax: Visual Basic*

     Public Property Transaction As MySqlTransaction

*Syntax: C#*

     public MySqlTransaction Transaction {get; set;}

*See Also*

*Note MySqlCommand Class: connector-net-ref-mysqlclient-mysqlcommand,
*Note MySql.Data.MySqlClient Namespace: connector-net-ref-mysqlclient.


File: manual.info,  Node: connector-net-ref-mysqlclient-mysqlcommand-updatedrowsource,  Next: connector-net-ref-mysqlclient-mysqlcommand-cancel,  Prev: connector-net-ref-mysqlclient-mysqlcommand-transaction,  Up: connector-net-ref-mysqlclient-mysqlcommandmembers

20.2.7.107 UpdatedRowSource Property
....................................

*Syntax: Visual Basic*

     NotOverridable Public Property UpdatedRowSource As UpdateRowSource _
     _
       Implements IDbCommand.UpdatedRowSource

*Syntax: C#*

     public System.Data.UpdateRowSource UpdatedRowSource {get; set;}

*Implements*

IDbCommand.UpdatedRowSource

*See Also*

*Note MySqlCommand Class: connector-net-ref-mysqlclient-mysqlcommand,
*Note MySql.Data.MySqlClient Namespace: connector-net-ref-mysqlclient.


File: manual.info,  Node: connector-net-ref-mysqlclient-mysqlcommand-cancel,  Next: connector-net-ref-mysqlclient-mysqlcommand-createparameter,  Prev: connector-net-ref-mysqlclient-mysqlcommand-updatedrowsource,  Up: connector-net-ref-mysqlclient-mysqlcommandmembers

20.2.7.108 `MySqlCommand.Cancel' Method
.......................................

Attempts to cancel the execution of a MySqlCommand. This operation is
not supported.

*Syntax: Visual Basic*

     NotOverridable Public Sub Cancel() _
     _
       Implements IDbCommand.Cancel

*Syntax: C#*

     public void Cancel();

*Implements*

IDbCommand.Cancel

*Remarks*

Cancelling an executing command is currently not supported on any
version of MySQL.

*Exceptions*

*Exception Type*                     *Condition*
NotSupportedException                This operation is not supported.

*See Also*

*Note MySqlCommand Class: connector-net-ref-mysqlclient-mysqlcommand,
*Note MySql.Data.MySqlClient Namespace: connector-net-ref-mysqlclient.


File: manual.info,  Node: connector-net-ref-mysqlclient-mysqlcommand-createparameter,  Next: connector-net-ref-mysqlclient-mysqlcommand-executenonquery,  Prev: connector-net-ref-mysqlclient-mysqlcommand-cancel,  Up: connector-net-ref-mysqlclient-mysqlcommandmembers

20.2.7.109 `MySqlCommand.CreateParameter' Method
................................................

Creates a new instance of a *Note MySqlParameter:
connector-net-ref-mysqlclient-mysqlparameter.  object.

*Syntax: Visual Basic*

     Public Function CreateParameter() As MySqlParameter

*Syntax: C#*

     public MySqlParameter CreateParameter();

*Return Value*

A *Note MySqlParameter: connector-net-ref-mysqlclient-mysqlparameter.
object.

*Remarks*

This method is a strongly-typed version of CreateParameter.

*See Also*

*Note MySqlCommand Class: connector-net-ref-mysqlclient-mysqlcommand,
*Note MySql.Data.MySqlClient Namespace: connector-net-ref-mysqlclient.


File: manual.info,  Node: connector-net-ref-mysqlclient-mysqlcommand-executenonquery,  Next: connector-net-ref-mysqlclient-mysqlcommand-executereader-overloads,  Prev: connector-net-ref-mysqlclient-mysqlcommand-createparameter,  Up: connector-net-ref-mysqlclient-mysqlcommandmembers

20.2.7.110 `MySqlCommand.ExecuteNonQuery' Method
................................................

*Syntax: Visual Basic*

     NotOverridable Public Function ExecuteNonQuery() As Integer _
     _
       Implements IDbCommand.ExecuteNonQuery

*Syntax: C#*

     public int ExecuteNonQuery();

*Implements*

IDbCommand.ExecuteNonQuery

*See Also*

*Note MySqlCommand Class: connector-net-ref-mysqlclient-mysqlcommand,
*Note MySql.Data.MySqlClient Namespace: connector-net-ref-mysqlclient.


File: manual.info,  Node: connector-net-ref-mysqlclient-mysqlcommand-executereader-overloads,  Next: connector-net-ref-mysqlclient-mysqlcommand-executescalar,  Prev: connector-net-ref-mysqlclient-mysqlcommand-executenonquery,  Up: connector-net-ref-mysqlclient-mysqlcommandmembers

20.2.7.111 ExecuteReader Method
...............................

* Menu:

* connector-net-ref-mysqlclient-mysqlcommand-executereader-overload-1::  `MySqlCommand.ExecuteReader' Method
* connector-net-ref-mysqlclient-mysqlcommand-executereader-overload-2::  `MySqlCommand.ExecuteReader' Method

*Overload List*

   * *Note public MySqlDataReader ExecuteReader();:
     connector-net-ref-mysqlclient-mysqlcommand-executereader-overload-1.

   * *Note public MySqlDataReader ExecuteReader(CommandBehavior);:
     connector-net-ref-mysqlclient-mysqlcommand-executereader-overload-2.

*See Also*

*Note MySqlCommand Class: connector-net-ref-mysqlclient-mysqlcommand,
*Note MySql.Data.MySqlClient Namespace: connector-net-ref-mysqlclient.


File: manual.info,  Node: connector-net-ref-mysqlclient-mysqlcommand-executereader-overload-1,  Next: connector-net-ref-mysqlclient-mysqlcommand-executereader-overload-2,  Prev: connector-net-ref-mysqlclient-mysqlcommand-executereader-overloads,  Up: connector-net-ref-mysqlclient-mysqlcommand-executereader-overloads

20.2.7.112 `MySqlCommand.ExecuteReader' Method
..............................................

* Menu:

* connector-net-ref-mysqlclient-mysqldatareader::  `MySqlDataReader' Class

*Syntax: Visual Basic*

     Overloads Public Function ExecuteReader() As MySqlDataReader

*Syntax: C#*

     public MySqlDataReader ExecuteReader();

*See Also*

*Note MySqlCommand Class: connector-net-ref-mysqlclient-mysqlcommand,
*Note MySql.Data.MySqlClient Namespace: connector-net-ref-mysqlclient,
*Note MySqlCommand.ExecuteReader Overload List:
connector-net-ref-mysqlclient-mysqlcommand-executereader-overloads.


File: manual.info,  Node: connector-net-ref-mysqlclient-mysqldatareader,  Prev: connector-net-ref-mysqlclient-mysqlcommand-executereader-overload-1,  Up: connector-net-ref-mysqlclient-mysqlcommand-executereader-overload-1

20.2.7.113 `MySqlDataReader' Class
..................................

* Menu:

* connector-net-ref-mysqlclient-mysqldatareadermembers::  `MySqlDataReader' Members

Provides a means of reading a forward-only stream of rows from a MySQL
database. This class cannot be inherited.

For a list of all members of this type, see *Note MySqlDataReader
Members: connector-net-ref-mysqlclient-mysqldatareadermembers .

*Syntax: Visual Basic*

     NotInheritable Public Class MySqlDataReader_
       Inherits MarshalByRefObject_
       Implements IEnumerable, IDataReader, IDisposable, IDataRecord

*Syntax: C#*

     public sealed class MySqlDataReader : MarshalByRefObject, IEnumerable, IDataReader, IDisposable, IDataRecord

*Thread Safety*

Public static (Shared in Visual Basic) members of this type are safe
for multithreaded operations. Instance members are not guaranteed to be
thread-safe.

*Requirements*

Namespace: *Note MySql.Data.MySqlClient: connector-net-ref-mysqlclient.

Assembly: MySql.Data (in MySql.Data.dll)

*See Also*

*Note MySqlDataReader Members:
connector-net-ref-mysqlclient-mysqldatareadermembers, *Note
MySql.Data.MySqlClient Namespace: connector-net-ref-mysqlclient.


File: manual.info,  Node: connector-net-ref-mysqlclient-mysqldatareadermembers,  Prev: connector-net-ref-mysqlclient-mysqldatareader,  Up: connector-net-ref-mysqlclient-mysqldatareader

20.2.7.114 `MySqlDataReader' Members
....................................

* Menu:

* connector-net-ref-mysqlclient-mysqldatareader-depth::  Depth Property
* connector-net-ref-mysqlclient-mysqldatareader-fieldcount::  FieldCount Property
* connector-net-ref-mysqlclient-mysqldatareader-hasrows::  HasRows Property
* connector-net-ref-mysqlclient-mysqldatareader-isclosed::  IsClosed Property
* connector-net-ref-mysqlclient-mysqldatareaderitem::  Item Property
* connector-net-ref-mysqlclient-mysqldatareader-recordsaffected::  RecordsAffected Property
* connector-net-ref-mysqlclient-mysqldatareader-close::  `MySqlDataReader.Close' Method
* connector-net-ref-mysqlclient-mysqldatareader-getboolean::  `MySqlDataReader.GetBoolean' Method
* connector-net-ref-mysqlclient-mysqldatareader-getbyte::  `MySqlDataReader.GetByte' Method
* connector-net-ref-mysqlclient-mysqldatareader-getbytes::  `MySqlDataReader.GetBytes' Method
* connector-net-ref-mysqlclient-mysqldatareader-getchar::  `MySqlDataReader.GetChar' Method
* connector-net-ref-mysqlclient-mysqldatareader-getchars::  `MySqlDataReader.GetChars' Method
* connector-net-ref-mysqlclient-mysqldatareader-getdatatypename::  `MySqlDataReader.GetDataTypeName' Method
* connector-net-ref-mysqlclient-mysqldatareader-getdatetime::  `MySqlDataReader.GetDateTime' Method
* connector-net-ref-mysqlclient-mysqldatareader-getdecimal::  `MySqlDataReader.GetDecimal' Method
* connector-net-ref-mysqlclient-mysqldatareader-getdouble::  `MySqlDataReader.GetDouble' Method
* connector-net-ref-mysqlclient-mysqldatareader-getfieldtype::  `MySqlDataReader.GetFieldType' Method
* connector-net-ref-mysqlclient-mysqldatareader-getfloat::  `MySqlDataReader.GetFloat' Method
* connector-net-ref-mysqlclient-mysqldatareader-getguid::  `MySqlDataReader.GetGuid' Method
* connector-net-ref-mysqlclient-mysqldatareader-getint16::  `MySqlDataReader.GetInt16' Method
* connector-net-ref-mysqlclient-mysqldatareader-getint32::  `MySqlDataReader.GetInt32' Method
* connector-net-ref-mysqlclient-mysqldatareader-getint64::  `MySqlDataReader.GetInt64' Method
* connector-net-ref-mysqlclient-mysqldatareader-getmysqldatetime::  `MySqlDataReader.GetMySqlDateTime' Method
* connector-net-ref-mysqlclient-mysqldatareader-getname::  `MySqlDataReader.GetName' Method
* connector-net-ref-mysqlclient-mysqldatareader-getordinal::  `MySqlDataReader.GetOrdinal' Method
* connector-net-ref-mysqlclient-mysqldatareader-getschematable::  `MySqlDataReader.GetSchemaTable' Method
* connector-net-ref-mysqlclient-mysqldatareader-getstring::  `MySqlDataReader.GetString' Method
* connector-net-ref-mysqlclient-mysqldatareader-gettimespan::  `MySqlDataReader.GetTimeSpan' Method
* connector-net-ref-mysqlclient-mysqldatareader-getuint16::  `MySqlDataReader.GetUInt16' Method
* connector-net-ref-mysqlclient-mysqldatareader-getuint32::  `MySqlDataReader.GetUInt32' Method
* connector-net-ref-mysqlclient-mysqldatareader-getuint64::  `MySqlDataReader.GetUInt64' Method
* connector-net-ref-mysqlclient-mysqldatareader-getvalue::  `MySqlDataReader.GetValue' Method
* connector-net-ref-mysqlclient-mysqldatareader-getvalues::  `MySqlDataReader.GetValues' Method
* connector-net-ref-mysqlclient-mysqldatareader-isdbnull::  `MySqlDataReader.IsDBNull' Method
* connector-net-ref-mysqlclient-mysqldatareader-nextresult::  `MySqlDataReader.NextResult' Method
* connector-net-ref-mysqlclient-mysqldatareader-read::  `MySqlDataReader.Read' Method

*Note MySqlDataReader overview:
connector-net-ref-mysqlclient-mysqldatareader.

*Public Instance Properties*

*Note Depth:                         Gets a value indicating the depth
connector-net-ref-mysqlclient-mysqldatareader-depth.of nesting for the current row. This
                                     method is not supported currently
                                     and always returns 0.
*Note FieldCount:                    Gets the number of columns in the
connector-net-ref-mysqlclient-mysqldatareader-fieldcount.current row.
*Note HasRows:                       Gets a value indicating whether the
connector-net-ref-mysqlclient-mysqldatareader-hasrows.MySqlDataReader contains one or more
                                     rows.
*Note IsClosed:                      Gets a value indicating whether the
connector-net-ref-mysqlclient-mysqldatareader-isclosed.data reader is closed.
*Note Item:                          Overloaded. Overloaded. Gets the
connector-net-ref-mysqlclient-mysqldatareaderitem.value of a column in its native
                                     format.  In C#, this property is
                                     the indexer for the MySqlDataReader
                                     class.
*Note RecordsAffected:               Gets the number of rows changed,
connector-net-ref-mysqlclient-mysqldatareader-recordsaffected.inserted, or deleted by execution of
                                     the SQL statement.

*Public Instance Methods*

*Note Close:                         Closes the MySqlDataReader object.
connector-net-ref-mysqlclient-mysqldatareader-close.
CreateObjRef(inherited from          Creates an object that contains all
MarshalByRefObject)                  the relevant information required to
                                     generate a proxy used to
                                     communicate with a remote object.
Equals(inherited from Object)        Determines whether the specified
                                     Objectis equal to the current
                                     Object.
*Note GetBoolean:                    Gets the value of the specified
connector-net-ref-mysqlclient-mysqldatareader-getboolean.column as a Boolean.
*Note GetByte:                       Gets the value of the specified
connector-net-ref-mysqlclient-mysqldatareader-getbyte.column as a byte.
*Note GetBytes:                      Reads a stream of bytes from the
connector-net-ref-mysqlclient-mysqldatareader-getbytes.specified column offset into the
                                     buffer an array starting at the
                                     given buffer offset.
*Note GetChar:                       Gets the value of the specified
connector-net-ref-mysqlclient-mysqldatareader-getchar.column as a single character.
*Note GetChars:                      Reads a stream of characters from
connector-net-ref-mysqlclient-mysqldatareader-getchars.the specified column offset into the
                                     buffer as an array starting at the
                                     given buffer offset.
*Note GetDataTypeName:               Gets the name of the source data
connector-net-ref-mysqlclient-mysqldatareader-getdatatypename.type.
*Note GetDateTime:                   
connector-net-ref-mysqlclient-mysqldatareader-getdatetime.
*Note GetDecimal:                    
connector-net-ref-mysqlclient-mysqldatareader-getdecimal.
*Note GetDouble:                     
connector-net-ref-mysqlclient-mysqldatareader-getdouble.
*Note GetFieldType:                  Gets the Type that is the data type
connector-net-ref-mysqlclient-mysqldatareader-getfieldtype.of the object.
*Note GetFloat:                      
connector-net-ref-mysqlclient-mysqldatareader-getfloat.
*Note GetGuid:                       
connector-net-ref-mysqlclient-mysqldatareader-getguid.
GetHashCode(inherited from Object)   Serves as a hash function for a
                                     particular type. GetHashCodeis
                                     suitable for use in hashing
                                     algorithms and data structures like
                                     a hash table.
*Note GetInt16:                      
connector-net-ref-mysqlclient-mysqldatareader-getint16.
*Note GetInt32:                      
connector-net-ref-mysqlclient-mysqldatareader-getint32.
*Note GetInt64:                      
connector-net-ref-mysqlclient-mysqldatareader-getint64.
GetLifetimeService(inherited from    Retrieves the current lifetime
MarshalByRefObject)                  service object that controls the
                                     lifetime policy for this instance.
*Note GetMySqlDateTime:              
connector-net-ref-mysqlclient-mysqldatareader-getmysqldatetime.
*Note GetName:                       Gets the name of the specified
connector-net-ref-mysqlclient-mysqldatareader-getname.column.
*Note GetOrdinal:                    Gets the column ordinal, given the
connector-net-ref-mysqlclient-mysqldatareader-getordinal.name of the column.
*Note GetSchemaTable:                Returns a DataTable that describes
connector-net-ref-mysqlclient-mysqldatareader-getschematable.the column metadata of the
                                     MySqlDataReader.
*Note GetString:                     
connector-net-ref-mysqlclient-mysqldatareader-getstring.
*Note GetTimeSpan:                   
connector-net-ref-mysqlclient-mysqldatareader-gettimespan.
GetType(inherited from Object)       Gets the Typeof the current
                                     instance.
*Note GetUInt16:                     
connector-net-ref-mysqlclient-mysqldatareader-getuint16.
*Note GetUInt32:                     
connector-net-ref-mysqlclient-mysqldatareader-getuint32.
*Note GetUInt64:                     
connector-net-ref-mysqlclient-mysqldatareader-getuint64.
*Note GetValue:                      Gets the value of the specified
connector-net-ref-mysqlclient-mysqldatareader-getvalue.column in its native format.
*Note GetValues:                     Gets all attribute columns in the
connector-net-ref-mysqlclient-mysqldatareader-getvalues.collection for the current row.
InitializeLifetimeService(inherited  Obtains a lifetime service object
from MarshalByRefObject)             to control the lifetime policy for
                                     this instance.
*Note IsDBNull:                      Gets a value indicating whether the
connector-net-ref-mysqlclient-mysqldatareader-isdbnull.column contains non-existent or
                                     missing values.
*Note NextResult:                    Advances the data reader to the
connector-net-ref-mysqlclient-mysqldatareader-nextresult.next result, when reading the
                                     results of batch SQL statements.
*Note Read:                          Advances the MySqlDataReader to the
connector-net-ref-mysqlclient-mysqldatareader-read.next record.
ToString(inherited from Object)      Returns a Stringthat represents the
                                     current Object.

*See Also*

*Note MySqlDataReader Class:
connector-net-ref-mysqlclient-mysqldatareader, *Note
MySql.Data.MySqlClient Namespace: connector-net-ref-mysqlclient.


File: manual.info,  Node: connector-net-ref-mysqlclient-mysqldatareader-depth,  Next: connector-net-ref-mysqlclient-mysqldatareader-fieldcount,  Prev: connector-net-ref-mysqlclient-mysqldatareadermembers,  Up: connector-net-ref-mysqlclient-mysqldatareadermembers

20.2.7.115 Depth Property
.........................

Gets a value indicating the depth of nesting for the current row. This
method is not supported currently and always returns 0.

*Syntax: Visual Basic*

     NotOverridable Public ReadOnly Property Depth As Integer _
     _
       Implements IDataReader.Depth

*Syntax: C#*

     public int Depth {get;}

*Implements*

IDataReader.Depth

*See Also*

*Note MySqlDataReader Class:
connector-net-ref-mysqlclient-mysqldatareader, *Note
MySql.Data.MySqlClient Namespace: connector-net-ref-mysqlclient.


File: manual.info,  Node: connector-net-ref-mysqlclient-mysqldatareader-fieldcount,  Next: connector-net-ref-mysqlclient-mysqldatareader-hasrows,  Prev: connector-net-ref-mysqlclient-mysqldatareader-depth,  Up: connector-net-ref-mysqlclient-mysqldatareadermembers

20.2.7.116 FieldCount Property
..............................

Gets the number of columns in the current row.

*Syntax: Visual Basic*

     NotOverridable Public ReadOnly Property FieldCount As Integer _
     _
       Implements IDataRecord.FieldCount

*Syntax: C#*

     public int FieldCount {get;}

*Implements*

IDataRecord.FieldCount

*See Also*

*Note MySqlDataReader Class:
connector-net-ref-mysqlclient-mysqldatareader, *Note
MySql.Data.MySqlClient Namespace: connector-net-ref-mysqlclient.


File: manual.info,  Node: connector-net-ref-mysqlclient-mysqldatareader-hasrows,  Next: connector-net-ref-mysqlclient-mysqldatareader-isclosed,  Prev: connector-net-ref-mysqlclient-mysqldatareader-fieldcount,  Up: connector-net-ref-mysqlclient-mysqldatareadermembers

20.2.7.117 HasRows Property
...........................

Gets a value indicating whether the MySqlDataReader contains one or
more rows.

*Syntax: Visual Basic*

     Public ReadOnly Property HasRows As Boolean

*Syntax: C#*

     public bool HasRows {get;}

*See Also*

*Note MySqlDataReader Class:
connector-net-ref-mysqlclient-mysqldatareader, *Note
MySql.Data.MySqlClient Namespace: connector-net-ref-mysqlclient.


File: manual.info,  Node: connector-net-ref-mysqlclient-mysqldatareader-isclosed,  Next: connector-net-ref-mysqlclient-mysqldatareaderitem,  Prev: connector-net-ref-mysqlclient-mysqldatareader-hasrows,  Up: connector-net-ref-mysqlclient-mysqldatareadermembers

20.2.7.118 IsClosed Property
............................

Gets a value indicating whether the data reader is closed.

*Syntax: Visual Basic*

     NotOverridable Public ReadOnly Property IsClosed As Boolean _
     _
       Implements IDataReader.IsClosed

*Syntax: C#*

     public bool IsClosed {get;}

*Implements*

IDataReader.IsClosed

*See Also*

*Note MySqlDataReader Class:
connector-net-ref-mysqlclient-mysqldatareader, *Note
MySql.Data.MySqlClient Namespace: connector-net-ref-mysqlclient.


File: manual.info,  Node: connector-net-ref-mysqlclient-mysqldatareaderitem,  Next: connector-net-ref-mysqlclient-mysqldatareader-recordsaffected,  Prev: connector-net-ref-mysqlclient-mysqldatareader-isclosed,  Up: connector-net-ref-mysqlclient-mysqldatareadermembers

20.2.7.119 Item Property
........................

* Menu:

* connector-net-ref-mysqlclient-mysqldatareader-item1::  Item Property (Int32)
* connector-net-ref-mysqlclient-mysqldatareader-item2::  Item Property (String)

Overloaded. Gets the value of a column in its native format. In C#,
this property is the indexer for the MySqlDataReader class.

*Overload List*

Overloaded. Gets the value of a column in its native format. In C#,
this property is the indexer for the MySqlDataReader class.

   * *Note public object this[int] {get;}:
     connector-net-ref-mysqlclient-mysqldatareader-item1.

Gets the value of a column in its native format. In C#, this property
is the indexer for the MySqlDataReader class.

   * *Note public object this[string] {get;}:
     connector-net-ref-mysqlclient-mysqldatareader-item2.

*See Also*

*Note MySqlDataReader Class:
connector-net-ref-mysqlclient-mysqldatareader, *Note
MySql.Data.MySqlClient Namespace: connector-net-ref-mysqlclient.


File: manual.info,  Node: connector-net-ref-mysqlclient-mysqldatareader-item1,  Next: connector-net-ref-mysqlclient-mysqldatareader-item2,  Prev: connector-net-ref-mysqlclient-mysqldatareaderitem,  Up: connector-net-ref-mysqlclient-mysqldatareaderitem

20.2.7.120 Item Property (Int32)
................................

Overloaded. Gets the value of a column in its native format. In C#,
this property is the indexer for the MySqlDataReader class.

*Syntax: Visual Basic*

     NotOverridable Overloads Public Default ReadOnly Property Item( _
        ByVal i As Integer _
     ) _
     _
       Implements IDataRecord.Item As Object _
     _
       Implements IDataRecord.Item

*Syntax: C#*

     public object this[
     inti
     ] {get;}

*Implements*

IDataRecord.Item

*See Also*

*Note MySqlDataReader Class:
connector-net-ref-mysqlclient-mysqldatareader, *Note
MySql.Data.MySqlClient Namespace: connector-net-ref-mysqlclient, *Note
MySqlDataReader.Item Overload List:
connector-net-ref-mysqlclient-mysqldatareaderitem.


File: manual.info,  Node: connector-net-ref-mysqlclient-mysqldatareader-item2,  Prev: connector-net-ref-mysqlclient-mysqldatareader-item1,  Up: connector-net-ref-mysqlclient-mysqldatareaderitem

20.2.7.121 Item Property (String)
.................................

Gets the value of a column in its native format.  In C#, this property
is the indexer for the MySqlDataReader class.

*Syntax: Visual Basic*

     NotOverridable Overloads Public Default ReadOnly Property Item( _
        ByVal name As String _
     ) _
     _
       Implements IDataRecord.Item As Object _
     _
       Implements IDataRecord.Item

*Syntax: C#*

     public object this[
     stringname
     ] {get;}

*Implements*

IDataRecord.Item

*See Also*

*Note MySqlDataReader Class:
connector-net-ref-mysqlclient-mysqldatareader, *Note
MySql.Data.MySqlClient Namespace: connector-net-ref-mysqlclient, *Note
MySqlDataReader.Item Overload List:
connector-net-ref-mysqlclient-mysqldatareaderitem.


File: manual.info,  Node: connector-net-ref-mysqlclient-mysqldatareader-recordsaffected,  Next: connector-net-ref-mysqlclient-mysqldatareader-close,  Prev: connector-net-ref-mysqlclient-mysqldatareaderitem,  Up: connector-net-ref-mysqlclient-mysqldatareadermembers

20.2.7.122 RecordsAffected Property
...................................

Gets the number of rows changed, inserted, or deleted by execution of
the SQL statement.

*Syntax: Visual Basic*

     NotOverridable Public ReadOnly Property RecordsAffected As Integer _
     _
       Implements IDataReader.RecordsAffected

*Syntax: C#*

     public int RecordsAffected {get;}

*Implements*

IDataReader.RecordsAffected

*See Also*

*Note MySqlDataReader Class:
connector-net-ref-mysqlclient-mysqldatareader, *Note
MySql.Data.MySqlClient Namespace: connector-net-ref-mysqlclient.


File: manual.info,  Node: connector-net-ref-mysqlclient-mysqldatareader-close,  Next: connector-net-ref-mysqlclient-mysqldatareader-getboolean,  Prev: connector-net-ref-mysqlclient-mysqldatareader-recordsaffected,  Up: connector-net-ref-mysqlclient-mysqldatareadermembers

20.2.7.123 `MySqlDataReader.Close' Method
.........................................

Closes the MySqlDataReader object.

*Syntax: Visual Basic*

     NotOverridable Public Sub Close() _
     _
       Implements IDataReader.Close

*Syntax: C#*

     public void Close();

*Implements*

IDataReader.Close

*See Also*

*Note MySqlDataReader Class:
connector-net-ref-mysqlclient-mysqldatareader, *Note
MySql.Data.MySqlClient Namespace: connector-net-ref-mysqlclient.


File: manual.info,  Node: connector-net-ref-mysqlclient-mysqldatareader-getboolean,  Next: connector-net-ref-mysqlclient-mysqldatareader-getbyte,  Prev: connector-net-ref-mysqlclient-mysqldatareader-close,  Up: connector-net-ref-mysqlclient-mysqldatareadermembers

20.2.7.124 `MySqlDataReader.GetBoolean' Method
..............................................

Gets the value of the specified column as a Boolean.

*Syntax: Visual Basic*

     NotOverridable Public Function GetBoolean( _
        ByVal i As Integer _
     ) As Boolean _
     _
       Implements IDataRecord.GetBoolean

*Syntax: C#*

     public bool GetBoolean(
     inti
     );

*Parameters*

   * `i':

*Return Value*

*Implements*

IDataRecord.GetBoolean

*See Also*

*Note MySqlDataReader Class:
connector-net-ref-mysqlclient-mysqldatareader, *Note
MySql.Data.MySqlClient Namespace: connector-net-ref-mysqlclient.


File: manual.info,  Node: connector-net-ref-mysqlclient-mysqldatareader-getbyte,  Next: connector-net-ref-mysqlclient-mysqldatareader-getbytes,  Prev: connector-net-ref-mysqlclient-mysqldatareader-getboolean,  Up: connector-net-ref-mysqlclient-mysqldatareadermembers

20.2.7.125 `MySqlDataReader.GetByte' Method
...........................................

Gets the value of the specified column as a byte.

*Syntax: Visual Basic*

     NotOverridable Public Function GetByte( _
        ByVal i As Integer _
     ) As Byte _
     _
       Implements IDataRecord.GetByte

*Syntax: C#*

     public byte GetByte(
     inti
     );

*Parameters*

   * `i':

*Return Value*

*Implements*

IDataRecord.GetByte

*See Also*

*Note MySqlDataReader Class:
connector-net-ref-mysqlclient-mysqldatareader, *Note
MySql.Data.MySqlClient Namespace: connector-net-ref-mysqlclient.


File: manual.info,  Node: connector-net-ref-mysqlclient-mysqldatareader-getbytes,  Next: connector-net-ref-mysqlclient-mysqldatareader-getchar,  Prev: connector-net-ref-mysqlclient-mysqldatareader-getbyte,  Up: connector-net-ref-mysqlclient-mysqldatareadermembers

20.2.7.126 `MySqlDataReader.GetBytes' Method
............................................

Reads a stream of bytes from the specified column offset into the
buffer an array starting at the given buffer offset.

*Syntax: Visual Basic*

     NotOverridable Public Function GetBytes( _
        ByVal i As Integer, _
        ByVal dataIndex As Long, _
        ByVal buffer As Byte(), _
        ByVal bufferIndex As Integer, _
        ByVal length As Integer _
     ) As Long _
     _
       Implements IDataRecord.GetBytes

*Syntax: C#*

     public long GetBytes(
     inti,
     longdataIndex,
     byte[]buffer,
     intbufferIndex,
     intlength
     );

*Parameters*

   * `i': The zero-based column ordinal.

   * `dataIndex': The index within the field from which to begin the
     read operation.

   * `buffer': The buffer into which to read the stream of bytes.

   * `bufferIndex': The index for buffer to begin the read operation.

   * `length': The maximum length to copy into the buffer.

*Return Value*

The actual number of bytes read.

*Implements*

IDataRecord.GetBytes

*See Also*

*Note MySqlDataReader Class:
connector-net-ref-mysqlclient-mysqldatareader, *Note
MySql.Data.MySqlClient Namespace: connector-net-ref-mysqlclient.


File: manual.info,  Node: connector-net-ref-mysqlclient-mysqldatareader-getchar,  Next: connector-net-ref-mysqlclient-mysqldatareader-getchars,  Prev: connector-net-ref-mysqlclient-mysqldatareader-getbytes,  Up: connector-net-ref-mysqlclient-mysqldatareadermembers

20.2.7.127 `MySqlDataReader.GetChar' Method
...........................................

Gets the value of the specified column as a single character.

*Syntax: Visual Basic*

     NotOverridable Public Function GetChar( _
        ByVal i As Integer _
     ) As Char _
     _
       Implements IDataRecord.GetChar

*Syntax: C#*

     public char GetChar(
     inti
     );

*Parameters*

   * `i':

*Return Value*

*Implements*

IDataRecord.GetChar

*See Also*

*Note MySqlDataReader Class:
connector-net-ref-mysqlclient-mysqldatareader, *Note
MySql.Data.MySqlClient Namespace: connector-net-ref-mysqlclient.


File: manual.info,  Node: connector-net-ref-mysqlclient-mysqldatareader-getchars,  Next: connector-net-ref-mysqlclient-mysqldatareader-getdatatypename,  Prev: connector-net-ref-mysqlclient-mysqldatareader-getchar,  Up: connector-net-ref-mysqlclient-mysqldatareadermembers

20.2.7.128 `MySqlDataReader.GetChars' Method
............................................

Reads a stream of characters from the specified column offset into the
buffer as an array starting at the given buffer offset.

*Syntax: Visual Basic*

     NotOverridable Public Function GetChars( _
        ByVal i As Integer, _
        ByVal fieldOffset As Long, _
        ByVal buffer As Char(), _
        ByVal bufferoffset As Integer, _
        ByVal length As Integer _
     ) As Long _
     _
       Implements IDataRecord.GetChars

*Syntax: C#*

     public long GetChars(
     inti,
     longfieldOffset,
     char[]buffer,
     intbufferoffset,
     intlength
     );

*Parameters*

   * `i':

   * `fieldOffset':

   * `buffer':

   * `bufferoffset':

   * `length':

*Return Value*

*Implements*

IDataRecord.GetChars

*See Also*

*Note MySqlDataReader Class:
connector-net-ref-mysqlclient-mysqldatareader, *Note
MySql.Data.MySqlClient Namespace: connector-net-ref-mysqlclient.


File: manual.info,  Node: connector-net-ref-mysqlclient-mysqldatareader-getdatatypename,  Next: connector-net-ref-mysqlclient-mysqldatareader-getdatetime,  Prev: connector-net-ref-mysqlclient-mysqldatareader-getchars,  Up: connector-net-ref-mysqlclient-mysqldatareadermembers

20.2.7.129 `MySqlDataReader.GetDataTypeName' Method
...................................................

Gets the name of the source data type.

*Syntax: Visual Basic*

     NotOverridable Public Function GetDataTypeName( _
        ByVal i As Integer _
     ) As String _
     _
       Implements IDataRecord.GetDataTypeName

*Syntax: C#*

     public string GetDataTypeName(
     inti
     );

*Parameters*

   * `i':

*Return Value*

*Implements*

IDataRecord.GetDataTypeName

*See Also*

*Note MySqlDataReader Class:
connector-net-ref-mysqlclient-mysqldatareader, *Note
MySql.Data.MySqlClient Namespace: connector-net-ref-mysqlclient.


File: manual.info,  Node: connector-net-ref-mysqlclient-mysqldatareader-getdatetime,  Next: connector-net-ref-mysqlclient-mysqldatareader-getdecimal,  Prev: connector-net-ref-mysqlclient-mysqldatareader-getdatatypename,  Up: connector-net-ref-mysqlclient-mysqldatareadermembers

20.2.7.130 `MySqlDataReader.GetDateTime' Method
...............................................

*Syntax: Visual Basic*

     NotOverridable Public Function GetDateTime( _
        ByVal index As Integer _
     ) As Date _
     _
       Implements IDataRecord.GetDateTime

*Syntax: C#*

     public DateTime GetDateTime(
     intindex
     );

*Implements*

IDataRecord.GetDateTime

*See Also*

*Note MySqlDataReader Class:
connector-net-ref-mysqlclient-mysqldatareader, *Note
MySql.Data.MySqlClient Namespace: connector-net-ref-mysqlclient.


File: manual.info,  Node: connector-net-ref-mysqlclient-mysqldatareader-getdecimal,  Next: connector-net-ref-mysqlclient-mysqldatareader-getdouble,  Prev: connector-net-ref-mysqlclient-mysqldatareader-getdatetime,  Up: connector-net-ref-mysqlclient-mysqldatareadermembers

20.2.7.131 `MySqlDataReader.GetDecimal' Method
..............................................

*Syntax: Visual Basic*

     NotOverridable Public Function GetDecimal( _
        ByVal index As Integer _
     ) As Decimal _
     _
       Implements IDataRecord.GetDecimal

*Syntax: C#*

     public decimal GetDecimal(
     intindex
     );

*Implements*

IDataRecord.GetDecimal

*See Also*

*Note MySqlDataReader Class:
connector-net-ref-mysqlclient-mysqldatareader, *Note
MySql.Data.MySqlClient Namespace: connector-net-ref-mysqlclient.


File: manual.info,  Node: connector-net-ref-mysqlclient-mysqldatareader-getdouble,  Next: connector-net-ref-mysqlclient-mysqldatareader-getfieldtype,  Prev: connector-net-ref-mysqlclient-mysqldatareader-getdecimal,  Up: connector-net-ref-mysqlclient-mysqldatareadermembers

20.2.7.132 `MySqlDataReader.GetDouble' Method
.............................................

*Syntax: Visual Basic*

     NotOverridable Public Function GetDouble( _
        ByVal index As Integer _
     ) As Double _
     _
       Implements IDataRecord.GetDouble

*Syntax: C#*

     public double GetDouble(
     intindex
     );

*Implements*

IDataRecord.GetDouble

*See Also*

*Note MySqlDataReader Class:
connector-net-ref-mysqlclient-mysqldatareader, *Note
MySql.Data.MySqlClient Namespace: connector-net-ref-mysqlclient.


File: manual.info,  Node: connector-net-ref-mysqlclient-mysqldatareader-getfieldtype,  Next: connector-net-ref-mysqlclient-mysqldatareader-getfloat,  Prev: connector-net-ref-mysqlclient-mysqldatareader-getdouble,  Up: connector-net-ref-mysqlclient-mysqldatareadermembers

20.2.7.133 `MySqlDataReader.GetFieldType' Method
................................................

Gets the Type that is the data type of the object.

*Syntax: Visual Basic*

     NotOverridable Public Function GetFieldType( _
        ByVal i As Integer _
     ) As Type _
     _
       Implements IDataRecord.GetFieldType

*Syntax: C#*

     public Type GetFieldType(
     inti
     );

*Parameters*

   * `i':

*Return Value*

*Implements*

IDataRecord.GetFieldType

*See Also*

*Note MySqlDataReader Class:
connector-net-ref-mysqlclient-mysqldatareader, *Note
MySql.Data.MySqlClient Namespace: connector-net-ref-mysqlclient.


File: manual.info,  Node: connector-net-ref-mysqlclient-mysqldatareader-getfloat,  Next: connector-net-ref-mysqlclient-mysqldatareader-getguid,  Prev: connector-net-ref-mysqlclient-mysqldatareader-getfieldtype,  Up: connector-net-ref-mysqlclient-mysqldatareadermembers

20.2.7.134 `MySqlDataReader.GetFloat' Method
............................................

*Syntax: Visual Basic*

     NotOverridable Public Function GetFloat( _
        ByVal index As Integer _
     ) As Single _
     _
       Implements IDataRecord.GetFloat

*Syntax: C#*

     public float GetFloat(
     intindex
     );

*Implements*

IDataRecord.GetFloat

*See Also*

*Note MySqlDataReader Class:
connector-net-ref-mysqlclient-mysqldatareader, *Note
MySql.Data.MySqlClient Namespace: connector-net-ref-mysqlclient.


File: manual.info,  Node: connector-net-ref-mysqlclient-mysqldatareader-getguid,  Next: connector-net-ref-mysqlclient-mysqldatareader-getint16,  Prev: connector-net-ref-mysqlclient-mysqldatareader-getfloat,  Up: connector-net-ref-mysqlclient-mysqldatareadermembers

20.2.7.135 `MySqlDataReader.GetGuid' Method
...........................................

*Syntax: Visual Basic*

     NotOverridable Public Function GetGuid( _
        ByVal index As Integer _
     ) As Guid _
     _
       Implements IDataRecord.GetGuid

*Syntax: C#*

     public Guid GetGuid(
     intindex
     );

*Implements*

IDataRecord.GetGuid

*See Also*

*Note MySqlDataReader Class:
connector-net-ref-mysqlclient-mysqldatareader, *Note
MySql.Data.MySqlClient Namespace: connector-net-ref-mysqlclient.


File: manual.info,  Node: connector-net-ref-mysqlclient-mysqldatareader-getint16,  Next: connector-net-ref-mysqlclient-mysqldatareader-getint32,  Prev: connector-net-ref-mysqlclient-mysqldatareader-getguid,  Up: connector-net-ref-mysqlclient-mysqldatareadermembers

20.2.7.136 `MySqlDataReader.GetInt16' Method
............................................

*Syntax: Visual Basic*

     NotOverridable Public Function GetInt16( _
        ByVal index As Integer _
     ) As Short _
     _
       Implements IDataRecord.GetInt16

*Syntax: C#*

     public short GetInt16(
     intindex
     );

*Implements*

IDataRecord.GetInt16

*See Also*

*Note MySqlDataReader Class:
connector-net-ref-mysqlclient-mysqldatareader, *Note
MySql.Data.MySqlClient Namespace: connector-net-ref-mysqlclient.


File: manual.info,  Node: connector-net-ref-mysqlclient-mysqldatareader-getint32,  Next: connector-net-ref-mysqlclient-mysqldatareader-getint64,  Prev: connector-net-ref-mysqlclient-mysqldatareader-getint16,  Up: connector-net-ref-mysqlclient-mysqldatareadermembers

20.2.7.137 `MySqlDataReader.GetInt32' Method
............................................

*Syntax: Visual Basic*

     NotOverridable Public Function GetInt32( _
        ByVal index As Integer _
     ) As Integer _
     _
       Implements IDataRecord.GetInt32

*Syntax: C#*

     public int GetInt32(
     intindex
     );

*Implements*

IDataRecord.GetInt32

*See Also*

*Note MySqlDataReader Class:
connector-net-ref-mysqlclient-mysqldatareader, *Note
MySql.Data.MySqlClient Namespace: connector-net-ref-mysqlclient.


File: manual.info,  Node: connector-net-ref-mysqlclient-mysqldatareader-getint64,  Next: connector-net-ref-mysqlclient-mysqldatareader-getmysqldatetime,  Prev: connector-net-ref-mysqlclient-mysqldatareader-getint32,  Up: connector-net-ref-mysqlclient-mysqldatareadermembers

20.2.7.138 `MySqlDataReader.GetInt64' Method
............................................

*Syntax: Visual Basic*

     NotOverridable Public Function GetInt64( _
        ByVal index As Integer _
     ) As Long _
     _
       Implements IDataRecord.GetInt64

*Syntax: C#*

     public long GetInt64(
     intindex
     );

*Implements*

IDataRecord.GetInt64

*See Also*

*Note MySqlDataReader Class:
connector-net-ref-mysqlclient-mysqldatareader, *Note
MySql.Data.MySqlClient Namespace: connector-net-ref-mysqlclient.


File: manual.info,  Node: connector-net-ref-mysqlclient-mysqldatareader-getmysqldatetime,  Next: connector-net-ref-mysqlclient-mysqldatareader-getname,  Prev: connector-net-ref-mysqlclient-mysqldatareader-getint64,  Up: connector-net-ref-mysqlclient-mysqldatareadermembers

20.2.7.139 `MySqlDataReader.GetMySqlDateTime' Method
....................................................

*Syntax: Visual Basic*

     Public Function GetMySqlDateTime( _
        ByVal index As Integer _
     ) As MySqlDateTime

*Syntax: C#*

     public MySqlDateTime GetMySqlDateTime(
     intindex
     );

*See Also*

*Note MySqlDataReader Class:
connector-net-ref-mysqlclient-mysqldatareader, *Note
MySql.Data.MySqlClient Namespace: connector-net-ref-mysqlclient.


File: manual.info,  Node: connector-net-ref-mysqlclient-mysqldatareader-getname,  Next: connector-net-ref-mysqlclient-mysqldatareader-getordinal,  Prev: connector-net-ref-mysqlclient-mysqldatareader-getmysqldatetime,  Up: connector-net-ref-mysqlclient-mysqldatareadermembers

20.2.7.140 `MySqlDataReader.GetName' Method
...........................................

Gets the name of the specified column.

*Syntax: Visual Basic*

     NotOverridable Public Function GetName( _
        ByVal i As Integer _
     ) As String _
     _
       Implements IDataRecord.GetName

*Syntax: C#*

     public string GetName(
     inti
     );

*Parameters*

   * `i':

*Return Value*

*Implements*

IDataRecord.GetName

*See Also*

*Note MySqlDataReader Class:
connector-net-ref-mysqlclient-mysqldatareader, *Note
MySql.Data.MySqlClient Namespace: connector-net-ref-mysqlclient.


File: manual.info,  Node: connector-net-ref-mysqlclient-mysqldatareader-getordinal,  Next: connector-net-ref-mysqlclient-mysqldatareader-getschematable,  Prev: connector-net-ref-mysqlclient-mysqldatareader-getname,  Up: connector-net-ref-mysqlclient-mysqldatareadermembers

20.2.7.141 `MySqlDataReader.GetOrdinal' Method
..............................................

Gets the column ordinal, given the name of the column.

*Syntax: Visual Basic*

     NotOverridable Public Function GetOrdinal( _
        ByVal name As String _
     ) As Integer _
     _
       Implements IDataRecord.GetOrdinal

*Syntax: C#*

     public int GetOrdinal(
     stringname
     );

*Parameters*

   * `name':

*Return Value*

*Implements*

IDataRecord.GetOrdinal

*See Also*

*Note MySqlDataReader Class:
connector-net-ref-mysqlclient-mysqldatareader, *Note
MySql.Data.MySqlClient Namespace: connector-net-ref-mysqlclient.


File: manual.info,  Node: connector-net-ref-mysqlclient-mysqldatareader-getschematable,  Next: connector-net-ref-mysqlclient-mysqldatareader-getstring,  Prev: connector-net-ref-mysqlclient-mysqldatareader-getordinal,  Up: connector-net-ref-mysqlclient-mysqldatareadermembers

20.2.7.142 `MySqlDataReader.GetSchemaTable' Method
..................................................

Returns a DataTable that describes the column metadata of the
MySqlDataReader.

*Syntax: Visual Basic*

     NotOverridable Public Function GetSchemaTable() As DataTable _
     _
       Implements IDataReader.GetSchemaTable

*Syntax: C#*

     public DataTable GetSchemaTable();

*Return Value*

*Implements*

IDataReader.GetSchemaTable

*See Also*

*Note MySqlDataReader Class:
connector-net-ref-mysqlclient-mysqldatareader, *Note
MySql.Data.MySqlClient Namespace: connector-net-ref-mysqlclient.


File: manual.info,  Node: connector-net-ref-mysqlclient-mysqldatareader-getstring,  Next: connector-net-ref-mysqlclient-mysqldatareader-gettimespan,  Prev: connector-net-ref-mysqlclient-mysqldatareader-getschematable,  Up: connector-net-ref-mysqlclient-mysqldatareadermembers

20.2.7.143 `MySqlDataReader.GetString' Method
.............................................

*Syntax: Visual Basic*

     NotOverridable Public Function GetString( _
        ByVal index As Integer _
     ) As String _
     _
       Implements IDataRecord.GetString

*Syntax: C#*

     public string GetString(
     intindex
     );

*Implements*

IDataRecord.GetString

*See Also*

*Note MySqlDataReader Class:
connector-net-ref-mysqlclient-mysqldatareader, *Note
MySql.Data.MySqlClient Namespace: connector-net-ref-mysqlclient.


File: manual.info,  Node: connector-net-ref-mysqlclient-mysqldatareader-gettimespan,  Next: connector-net-ref-mysqlclient-mysqldatareader-getuint16,  Prev: connector-net-ref-mysqlclient-mysqldatareader-getstring,  Up: connector-net-ref-mysqlclient-mysqldatareadermembers

20.2.7.144 `MySqlDataReader.GetTimeSpan' Method
...............................................

*Syntax: Visual Basic*

     Public Function GetTimeSpan( _
        ByVal index As Integer _
     ) As TimeSpan

*Syntax: C#*

     public TimeSpan GetTimeSpan(
     intindex
     );

*See Also*

*Note MySqlDataReader Class:
connector-net-ref-mysqlclient-mysqldatareader, *Note
MySql.Data.MySqlClient Namespace: connector-net-ref-mysqlclient.


File: manual.info,  Node: connector-net-ref-mysqlclient-mysqldatareader-getuint16,  Next: connector-net-ref-mysqlclient-mysqldatareader-getuint32,  Prev: connector-net-ref-mysqlclient-mysqldatareader-gettimespan,  Up: connector-net-ref-mysqlclient-mysqldatareadermembers

20.2.7.145 `MySqlDataReader.GetUInt16' Method
.............................................

*Syntax: Visual Basic*

     Public Function GetUInt16( _
        ByVal index As Integer _
     ) As UInt16

*Syntax: C#*

     public ushort GetUInt16(
     intindex
     );

*See Also*

*Note MySqlDataReader Class:
connector-net-ref-mysqlclient-mysqldatareader, *Note
MySql.Data.MySqlClient Namespace: connector-net-ref-mysqlclient.


File: manual.info,  Node: connector-net-ref-mysqlclient-mysqldatareader-getuint32,  Next: connector-net-ref-mysqlclient-mysqldatareader-getuint64,  Prev: connector-net-ref-mysqlclient-mysqldatareader-getuint16,  Up: connector-net-ref-mysqlclient-mysqldatareadermembers

20.2.7.146 `MySqlDataReader.GetUInt32' Method
.............................................

*Syntax: Visual Basic*

     Public Function GetUInt32( _
        ByVal index As Integer _
     ) As UInt32

*Syntax: C#*

     public uint GetUInt32(
     intindex
     );

*See Also*

*Note MySqlDataReader Class:
connector-net-ref-mysqlclient-mysqldatareader, *Note
MySql.Data.MySqlClient Namespace: connector-net-ref-mysqlclient.


File: manual.info,  Node: connector-net-ref-mysqlclient-mysqldatareader-getuint64,  Next: connector-net-ref-mysqlclient-mysqldatareader-getvalue,  Prev: connector-net-ref-mysqlclient-mysqldatareader-getuint32,  Up: connector-net-ref-mysqlclient-mysqldatareadermembers

20.2.7.147 `MySqlDataReader.GetUInt64' Method
.............................................

*Syntax: Visual Basic*

     Public Function GetUInt64( _
        ByVal index As Integer _
     ) As UInt64

*Syntax: C#*

     public ulong GetUInt64(
     intindex
     );

*See Also*

*Note MySqlDataReader Class:
connector-net-ref-mysqlclient-mysqldatareader, *Note
MySql.Data.MySqlClient Namespace: connector-net-ref-mysqlclient.


File: manual.info,  Node: connector-net-ref-mysqlclient-mysqldatareader-getvalue,  Next: connector-net-ref-mysqlclient-mysqldatareader-getvalues,  Prev: connector-net-ref-mysqlclient-mysqldatareader-getuint64,  Up: connector-net-ref-mysqlclient-mysqldatareadermembers

20.2.7.148 `MySqlDataReader.GetValue' Method
............................................

Gets the value of the specified column in its native format.

*Syntax: Visual Basic*

     NotOverridable Public Function GetValue( _
        ByVal i As Integer _
     ) As Object _
     _
       Implements IDataRecord.GetValue

*Syntax: C#*

     public object GetValue(
     inti
     );

*Parameters*

   * `i':

*Return Value*

*Implements*

IDataRecord.GetValue

*See Also*

*Note MySqlDataReader Class:
connector-net-ref-mysqlclient-mysqldatareader, *Note
MySql.Data.MySqlClient Namespace: connector-net-ref-mysqlclient.


File: manual.info,  Node: connector-net-ref-mysqlclient-mysqldatareader-getvalues,  Next: connector-net-ref-mysqlclient-mysqldatareader-isdbnull,  Prev: connector-net-ref-mysqlclient-mysqldatareader-getvalue,  Up: connector-net-ref-mysqlclient-mysqldatareadermembers

20.2.7.149 `MySqlDataReader.GetValues' Method
.............................................

Gets all attribute columns in the collection for the current row.

*Syntax: Visual Basic*

     NotOverridable Public Function GetValues( _
        ByVal values As Object() _
     ) As Integer _
     _
       Implements IDataRecord.GetValues

*Syntax: C#*

     public int GetValues(
     object[]values
     );

*Parameters*

   * `values':

*Return Value*

*Implements*

IDataRecord.GetValues

*See Also*

*Note MySqlDataReader Class:
connector-net-ref-mysqlclient-mysqldatareader, *Note
MySql.Data.MySqlClient Namespace: connector-net-ref-mysqlclient.


File: manual.info,  Node: connector-net-ref-mysqlclient-mysqldatareader-isdbnull,  Next: connector-net-ref-mysqlclient-mysqldatareader-nextresult,  Prev: connector-net-ref-mysqlclient-mysqldatareader-getvalues,  Up: connector-net-ref-mysqlclient-mysqldatareadermembers

20.2.7.150 `MySqlDataReader.IsDBNull' Method
............................................

Gets a value indicating whether the column contains non-existent or
missing values.

*Syntax: Visual Basic*

     NotOverridable Public Function IsDBNull( _
        ByVal i As Integer _
     ) As Boolean _
     _
       Implements IDataRecord.IsDBNull

*Syntax: C#*

     public bool IsDBNull(
     inti
     );

*Parameters*

   * `i':

*Return Value*

*Implements*

IDataRecord.IsDBNull

*See Also*

*Note MySqlDataReader Class:
connector-net-ref-mysqlclient-mysqldatareader, *Note
MySql.Data.MySqlClient Namespace: connector-net-ref-mysqlclient.


File: manual.info,  Node: connector-net-ref-mysqlclient-mysqldatareader-nextresult,  Next: connector-net-ref-mysqlclient-mysqldatareader-read,  Prev: connector-net-ref-mysqlclient-mysqldatareader-isdbnull,  Up: connector-net-ref-mysqlclient-mysqldatareadermembers

20.2.7.151 `MySqlDataReader.NextResult' Method
..............................................

Advances the data reader to the next result, when reading the results
of batch SQL statements.

*Syntax: Visual Basic*

     NotOverridable Public Function NextResult() As Boolean _
     _
       Implements IDataReader.NextResult

*Syntax: C#*

     public bool NextResult();

*Return Value*

*Implements*

IDataReader.NextResult

*See Also*

*Note MySqlDataReader Class:
connector-net-ref-mysqlclient-mysqldatareader, *Note
MySql.Data.MySqlClient Namespace: connector-net-ref-mysqlclient.


File: manual.info,  Node: connector-net-ref-mysqlclient-mysqldatareader-read,  Prev: connector-net-ref-mysqlclient-mysqldatareader-nextresult,  Up: connector-net-ref-mysqlclient-mysqldatareadermembers

20.2.7.152 `MySqlDataReader.Read' Method
........................................

Advances the MySqlDataReader to the next record.

*Syntax: Visual Basic*

     NotOverridable Public Function Read() As Boolean _
     _
       Implements IDataReader.Read

*Syntax: C#*

     public bool Read();

*Return Value*

*Implements*

IDataReader.Read

*See Also*

*Note MySqlDataReader Class:
connector-net-ref-mysqlclient-mysqldatareader, *Note
MySql.Data.MySqlClient Namespace: connector-net-ref-mysqlclient.


File: manual.info,  Node: connector-net-ref-mysqlclient-mysqlcommand-executereader-overload-2,  Prev: connector-net-ref-mysqlclient-mysqlcommand-executereader-overload-1,  Up: connector-net-ref-mysqlclient-mysqlcommand-executereader-overloads

20.2.7.153 `MySqlCommand.ExecuteReader' Method
..............................................

*Syntax: Visual Basic*

     Overloads Public Function ExecuteReader( _
        ByVal behavior As CommandBehavior _
     ) As MySqlDataReader

*Syntax: C#*

     public MySqlDataReader ExecuteReader(
     CommandBehaviorbehavior
     );

*See Also*

*Note MySqlCommand Class: connector-net-ref-mysqlclient-mysqlcommand,
*Note MySql.Data.MySqlClient Namespace: connector-net-ref-mysqlclient,
*Note MySqlCommand.ExecuteReader Overload List:
connector-net-ref-mysqlclient-mysqlcommand-executereader-overloads.


File: manual.info,  Node: connector-net-ref-mysqlclient-mysqlcommand-executescalar,  Next: connector-net-ref-mysqlclient-mysqlcommand-prepare,  Prev: connector-net-ref-mysqlclient-mysqlcommand-executereader-overloads,  Up: connector-net-ref-mysqlclient-mysqlcommandmembers

20.2.7.154 `MySqlCommand.ExecuteScalar' Method
..............................................

*Syntax: Visual Basic*

     NotOverridable Public Function ExecuteScalar() As Object _
     _
       Implements IDbCommand.ExecuteScalar

*Syntax: C#*

     public object ExecuteScalar();

*Implements*

IDbCommand.ExecuteScalar

*See Also*

*Note MySqlCommand Class: connector-net-ref-mysqlclient-mysqlcommand,
*Note MySql.Data.MySqlClient Namespace: connector-net-ref-mysqlclient.


File: manual.info,  Node: connector-net-ref-mysqlclient-mysqlcommand-prepare,  Prev: connector-net-ref-mysqlclient-mysqlcommand-executescalar,  Up: connector-net-ref-mysqlclient-mysqlcommandmembers

20.2.7.155 `MySqlCommand.Prepare' Method
........................................

*Syntax: Visual Basic*

     NotOverridable Public Sub Prepare() _
     _
       Implements IDbCommand.Prepare

*Syntax: C#*

     public void Prepare();

*Implements*

IDbCommand.Prepare

*See Also*

*Note MySqlCommand Class: connector-net-ref-mysqlclient-mysqlcommand,
*Note MySql.Data.MySqlClient Namespace: connector-net-ref-mysqlclient.


File: manual.info,  Node: connector-net-ref-mysqlclient-mysqlcommandbuilder,  Next: connector-net-ref-mysqlclient-mysqlexception,  Prev: connector-net-ref-mysqlclient-mysqlcommand,  Up: connector-net-ref-mysqlclient

20.2.7.156 `MySqlCommandBuilder' Class
......................................

* Menu:

* connector-net-ref-mysqlclient-mysqlcommandbuildermembers::  `MySqlCommandBuilder' Members

For a list of all members of this type, see *Note MySqlCommandBuilder
Members: connector-net-ref-mysqlclient-mysqlcommandbuildermembers .

*Syntax: Visual Basic*

     NotInheritable Public Class MySqlCommandBuilder_
       Inherits Component

*Syntax: C#*

     public sealed class MySqlCommandBuilder : Component

*Thread Safety*

Public static (Sharedin Visual Basic) members of this type are safe for
multithreaded operations. Instance members are notguaranteed to be
thread-safe.

*Requirements*

Namespace: *Note MySql.Data.MySqlClient: connector-net-ref-mysqlclient.

Assembly: MySql.Data (in MySql.Data.dll)

*See Also*

*Note MySqlCommandBuilder Members:
connector-net-ref-mysqlclient-mysqlcommandbuildermembers, *Note
MySql.Data.MySqlClient Namespace: connector-net-ref-mysqlclient.


File: manual.info,  Node: connector-net-ref-mysqlclient-mysqlcommandbuildermembers,  Prev: connector-net-ref-mysqlclient-mysqlcommandbuilder,  Up: connector-net-ref-mysqlclient-mysqlcommandbuilder

20.2.7.157 `MySqlCommandBuilder' Members
........................................

* Menu:

* connector-net-ref-mysqlclient-mysqlcommandbuilder-deriveparameters-overloads::  DeriveParameters Method
* connector-net-ref-mysqlclient-mysqlcommandbuilderconstructor::  `MySqlCommandBuilder' Constructor
* connector-net-ref-mysqlclient-mysqlcommandbuilder-dataadapter::  DataAdapter Property
* connector-net-ref-mysqlclient-mysqlcommandbuilder-quoteprefix::  QuotePrefix Property
* connector-net-ref-mysqlclient-mysqlcommandbuilder-quotesuffix::  QuoteSuffix Property
* connector-net-ref-mysqlclient-mysqlcommandbuilder-getdeletecommand::  `MySqlCommandBuilder.GetDeleteCommand' Method
* connector-net-ref-mysqlclient-mysqlcommandbuilder-getinsertcommand::  `MySqlCommandBuilder.GetInsertCommand' Method
* connector-net-ref-mysqlclient-mysqlcommandbuilder-getupdatecommand::  `MySqlCommandBuilder.GetUpdateCommand' Method
* connector-net-ref-mysqlclient-mysqlcommandbuilder-refreshschema::  `MySqlCommandBuilder.RefreshSchema' Method

*Note MySqlCommandBuilder overview:
connector-net-ref-mysqlclient-mysqlcommandbuilder.

*Public Static (Shared) Methods*

*Note DeriveParameters:              Overloaded. Retrieves parameter
connector-net-ref-mysqlclient-mysqlcommandbuilder-deriveparameters-overloads.information from the stored
                                     procedure specified in the
                                     MySqlCommand and populates the
                                     Parameters collection of the
                                     specified MySqlCommand object. This
                                     method is not currently supported
                                     since stored procedures are not
                                     available in MySql.

*Public Instance Constructors*

*Note MySqlCommandBuilder:           Overloaded. Initializes a new
connector-net-ref-mysqlclient-mysqlcommandbuilderconstructor.instance of the MySqlCommandBuilder
                                     class.

*Public Instance Properties*

Container(inherited from Component)  Gets the IContainerthat contains
                                     the Component.
*Note DataAdapter:                   
connector-net-ref-mysqlclient-mysqlcommandbuilder-dataadapter.
*Note QuotePrefix:                   
connector-net-ref-mysqlclient-mysqlcommandbuilder-quoteprefix.
*Note QuoteSuffix:                   
connector-net-ref-mysqlclient-mysqlcommandbuilder-quotesuffix.
Site(inherited from Component)       Gets or sets the ISiteof the
                                     Component.

*Public Instance Methods*

CreateObjRef(inherited from          Creates an object that contains all
MarshalByRefObject)                  the relevant information required to
                                     generate a proxy used to
                                     communicate with a remote object.
Dispose(inherited from Component)    Releases all resources used by the
                                     Component.
Equals(inherited from Object)        Determines whether the specified
                                     Objectis equal to the current
                                     Object.
*Note GetDeleteCommand:              
connector-net-ref-mysqlclient-mysqlcommandbuilder-getdeletecommand.
GetHashCode(inherited from Object)   Serves as a hash function for a
                                     particular type. GetHashCodeis
                                     suitable for use in hashing
                                     algorithms and data structures like
                                     a hash table.
*Note GetInsertCommand:              
connector-net-ref-mysqlclient-mysqlcommandbuilder-getinsertcommand.
GetLifetimeService(inherited from    Retrieves the current lifetime
MarshalByRefObject)                  service object that controls the
                                     lifetime policy for this instance.
GetType(inherited from Object)       Gets the Typeof the current
                                     instance.
*Note GetUpdateCommand:              
connector-net-ref-mysqlclient-mysqlcommandbuilder-getupdatecommand.
InitializeLifetimeService(inherited  Obtains a lifetime service object
from MarshalByRefObject)             to control the lifetime policy for
                                     this instance.
*Note RefreshSchema:                 
connector-net-ref-mysqlclient-mysqlcommandbuilder-refreshschema.
ToString(inherited from Component)   Returns a Stringcontaining the name
                                     of the Component, if any. This
                                     method should not be overridden.

*Public Instance Events*

Disposed(inherited from Component)   Adds an event handler to listen to
                                     the Disposedevent on the component.

*See Also*

*Note MySqlCommandBuilder Class:
connector-net-ref-mysqlclient-mysqlcommandbuilder, *Note
MySql.Data.MySqlClient Namespace: connector-net-ref-mysqlclient.


File: manual.info,  Node: connector-net-ref-mysqlclient-mysqlcommandbuilder-deriveparameters-overloads,  Next: connector-net-ref-mysqlclient-mysqlcommandbuilderconstructor,  Prev: connector-net-ref-mysqlclient-mysqlcommandbuildermembers,  Up: connector-net-ref-mysqlclient-mysqlcommandbuildermembers

20.2.7.158 DeriveParameters Method
..................................

* Menu:

* connector-net-ref-mysqlclient-mysqlcommandbuilder-deriveparameters-overload-1::  `MySqlCommandBuilder.DeriveParameters' Method
* connector-net-ref-mysqlclient-mysqlcommandbuilder-deriveparameters-overload-2::  `MySqlCommandBuilder.DeriveParameters' Method

Retrieves parameter information from the stored procedure specified in
the MySqlCommand and populates the Parameters collection of the
specified MySqlCommand object. This method is not currently supported
since stored procedures are not available in MySql.

*Overload List*

Retrieves parameter information from the stored procedure specified in
the MySqlCommand and populates the Parameters collection of the
specified MySqlCommand object. This method is not currently supported
since stored procedures are not available in MySql.

   * *Note public static void DeriveParameters(MySqlCommand);:
     connector-net-ref-mysqlclient-mysqlcommandbuilder-deriveparameters-overload-1.

   * *Note public static void DeriveParameters(MySqlCommand:
     (bool);)connector-net-ref-mysqlclient-mysqlcommandbuilder-deriveparameters-overload-2.

*See Also*

*Note MySqlCommandBuilder Class:
connector-net-ref-mysqlclient-mysqlcommandbuilder, *Note
MySql.Data.MySqlClient Namespace: connector-net-ref-mysqlclient.


File: manual.info,  Node: connector-net-ref-mysqlclient-mysqlcommandbuilder-deriveparameters-overload-1,  Next: connector-net-ref-mysqlclient-mysqlcommandbuilder-deriveparameters-overload-2,  Prev: connector-net-ref-mysqlclient-mysqlcommandbuilder-deriveparameters-overloads,  Up: connector-net-ref-mysqlclient-mysqlcommandbuilder-deriveparameters-overloads

20.2.7.159 `MySqlCommandBuilder.DeriveParameters' Method
........................................................

Retrieves parameter information from the stored procedure specified in
the MySqlCommand and populates the Parameters collection of the
specified MySqlCommand object. This method is not currently supported
since stored procedures are not available in MySql.

*Syntax: Visual Basic*

     Overloads Public Shared Sub DeriveParameters( _
        ByVal command As MySqlCommand _
     )

*Syntax: C#*

     public static void DeriveParameters(
     MySqlCommandcommand
     );

*Parameters*

   * `command': The MySqlCommand referencing the stored procedure from
     which the parameter information is to be derived. The derived
     parameters are added to the Parameters collection of the
     MySqlCommand.

*Exceptions*

*Exception Type*                     *Condition*
InvalidOperationException            The command text is not a valid
                                     stored procedure name.

*See Also*

*Note MySqlCommandBuilder Class:
connector-net-ref-mysqlclient-mysqlcommandbuilder, *Note
MySql.Data.MySqlClient Namespace: connector-net-ref-mysqlclient, *Note
MySqlCommandBuilder.DeriveParameters Overload List:
connector-net-ref-mysqlclient-mysqlcommandbuilder-deriveparameters-overloads.


File: manual.info,  Node: connector-net-ref-mysqlclient-mysqlcommandbuilder-deriveparameters-overload-2,  Prev: connector-net-ref-mysqlclient-mysqlcommandbuilder-deriveparameters-overload-1,  Up: connector-net-ref-mysqlclient-mysqlcommandbuilder-deriveparameters-overloads

20.2.7.160 `MySqlCommandBuilder.DeriveParameters' Method
........................................................

*Syntax: Visual Basic*

     Overloads Public Shared Sub DeriveParameters( _
        ByVal command As MySqlCommand, _
        ByVal useProc As Boolean _
     )

*Syntax: C#*

     public static void DeriveParameters(
     MySqlCommandcommand,
     booluseProc
     );

*See Also*

*Note MySqlCommandBuilder Class:
connector-net-ref-mysqlclient-mysqlcommandbuilder, *Note
MySql.Data.MySqlClient Namespace: connector-net-ref-mysqlclient, *Note
MySqlCommandBuilder.DeriveParameters Overload List:
connector-net-ref-mysqlclient-mysqlcommandbuilder-deriveparameters-overloads.


File: manual.info,  Node: connector-net-ref-mysqlclient-mysqlcommandbuilderconstructor,  Next: connector-net-ref-mysqlclient-mysqlcommandbuilder-dataadapter,  Prev: connector-net-ref-mysqlclient-mysqlcommandbuilder-deriveparameters-overloads,  Up: connector-net-ref-mysqlclient-mysqlcommandbuildermembers

20.2.7.161 `MySqlCommandBuilder' Constructor
............................................

* Menu:

* connector-net-ref-mysqlclient-mysqlcommandbuilderconstructor1::  `MySqlCommandBuilder' Constructor
* connector-net-ref-mysqlclient-mysqlcommandbuilderconstructor3::  `MySqlCommandBuilder' Constructor
* connector-net-ref-mysqlclient-mysqlcommandbuilderconstructor4::  `MySqlCommandBuilder' Constructor
* connector-net-ref-mysqlclient-mysqlcommandbuilderconstructor2::  `MySqlCommandBuilder' Constructor

Initializes a new instance of the *Note MySqlCommandBuilder:
connector-net-ref-mysqlclient-mysqlcommandbuilder.  class.

*Overload List*

Initializes a new instance of the *Note MySqlCommandBuilder:
connector-net-ref-mysqlclient-mysqlcommandbuilder.  class.

   * *Note public MySqlCommandBuilder();:
     connector-net-ref-mysqlclient-mysqlcommandbuilderconstructor1.

   * *Note public MySqlCommandBuilder(MySqlDataAdapter);:
     connector-net-ref-mysqlclient-mysqlcommandbuilderconstructor3.

   * *Note public MySqlCommandBuilder(MySqlDataAdapter:
     (bool);)connector-net-ref-mysqlclient-mysqlcommandbuilderconstructor4.

   * *Note public MySqlCommandBuilder(bool);:
     connector-net-ref-mysqlclient-mysqlcommandbuilderconstructor2.

*See Also*

*Note MySqlCommandBuilder Class:
connector-net-ref-mysqlclient-mysqlcommandbuilder, *Note
MySql.Data.MySqlClient Namespace: connector-net-ref-mysqlclient.


File: manual.info,  Node: connector-net-ref-mysqlclient-mysqlcommandbuilderconstructor1,  Next: connector-net-ref-mysqlclient-mysqlcommandbuilderconstructor3,  Prev: connector-net-ref-mysqlclient-mysqlcommandbuilderconstructor,  Up: connector-net-ref-mysqlclient-mysqlcommandbuilderconstructor

20.2.7.162 `MySqlCommandBuilder' Constructor
............................................

Initializes a new instance of the *Note MySqlCommandBuilder:
connector-net-ref-mysqlclient-mysqlcommandbuilder.  class.

*Syntax: Visual Basic*

     Overloads Public Sub New()

*Syntax: C#*

     public MySqlCommandBuilder();

*See Also*

*Note MySqlCommandBuilder Class:
connector-net-ref-mysqlclient-mysqlcommandbuilder, *Note
MySql.Data.MySqlClient Namespace: connector-net-ref-mysqlclient, *Note
MySqlCommandBuilder Constructor Overload List:
connector-net-ref-mysqlclient-mysqlcommandbuilderconstructor.


File: manual.info,  Node: connector-net-ref-mysqlclient-mysqlcommandbuilderconstructor3,  Next: connector-net-ref-mysqlclient-mysqlcommandbuilderconstructor4,  Prev: connector-net-ref-mysqlclient-mysqlcommandbuilderconstructor1,  Up: connector-net-ref-mysqlclient-mysqlcommandbuilderconstructor

20.2.7.163 `MySqlCommandBuilder' Constructor
............................................

* Menu:

* connector-net-ref-mysqlclient-mysqldataadapter::  `MySqlDataAdapter' Class

*Syntax: Visual Basic*

     Overloads Public Sub New( _
        ByVal adapter As MySqlDataAdapter _
     )

*Syntax: C#*

     public MySqlCommandBuilder(
     MySqlDataAdapteradapter
     );

*See Also*

*Note MySqlCommandBuilder Class:
connector-net-ref-mysqlclient-mysqlcommandbuilder, *Note
MySql.Data.MySqlClient Namespace: connector-net-ref-mysqlclient, *Note
MySqlCommandBuilder Constructor Overload List:
connector-net-ref-mysqlclient-mysqlcommandbuilderconstructor.


File: manual.info,  Node: connector-net-ref-mysqlclient-mysqldataadapter,  Prev: connector-net-ref-mysqlclient-mysqlcommandbuilderconstructor3,  Up: connector-net-ref-mysqlclient-mysqlcommandbuilderconstructor3

20.2.7.164 `MySqlDataAdapter' Class
...................................

* Menu:

* connector-net-ref-mysqlclient-mysqldataadaptermembers::  `MySqlDataAdapter' Members

For a list of all members of this type, see *Note MySqlDataAdapter
Members: connector-net-ref-mysqlclient-mysqldataadaptermembers .

*Syntax: Visual Basic*

     NotInheritable Public Class MySqlDataAdapter_
       Inherits DbDataAdapter

*Syntax: C#*

     public sealed class MySqlDataAdapter : DbDataAdapter

*Thread Safety*

Public static (Sharedin Visual Basic) members of this type are safe for
multithreaded operations. Instance members are notguaranteed to be
thread-safe.

*Requirements*

Namespace: *Note MySql.Data.MySqlClient: connector-net-ref-mysqlclient.

Assembly: MySql.Data (in MySql.Data.dll)

*See Also*

*Note MySqlDataAdapter Members:
connector-net-ref-mysqlclient-mysqldataadaptermembers, *Note
MySql.Data.MySqlClient Namespace: connector-net-ref-mysqlclient.


File: manual.info,  Node: connector-net-ref-mysqlclient-mysqldataadaptermembers,  Prev: connector-net-ref-mysqlclient-mysqldataadapter,  Up: connector-net-ref-mysqlclient-mysqldataadapter

20.2.7.165 `MySqlDataAdapter' Members
.....................................

* Menu:

* connector-net-ref-mysqlclient-mysqldataadapterconstructor::  `MySqlDataAdapter' Constructor
* connector-net-ref-mysqlclient-mysqldataadapter-deletecommand1::  DeleteCommand Property
* connector-net-ref-mysqlclient-mysqldataadapter-insertcommand1::  InsertCommand Property
* connector-net-ref-mysqlclient-mysqldataadapter-selectcommand1::  SelectCommand Property
* connector-net-ref-mysqlclient-mysqldataadapter-updatecommand1::  UpdateCommand Property
* connector-net-ref-mysqlclient-mysqldataadapter-rowupdated::  `MySqlDataAdapter.RowUpdated' Event
* connector-net-ref-mysqlclient-mysqldataadapter-rowupdating::  `MySqlDataAdapter.RowUpdating' Event

*Note MySqlDataAdapter overview:
connector-net-ref-mysqlclient-mysqldataadapter.

*Public Instance Constructors*

*Note MySqlDataAdapter:              Overloaded. Initializes a new
connector-net-ref-mysqlclient-mysqldataadapterconstructor.instance of the MySqlDataAdapter
                                     class.

*Public Instance Properties*

AcceptChangesDuringFill(inherited    Gets or sets a value indicating
from DataAdapter)                    whether AcceptChangesis called on a
                                     DataRowafter it is added to the
                                     DataTableduring any of the Fill
                                     operations.
AcceptChangesDuringUpdate(inherited  Gets or sets whether
from DataAdapter)                    AcceptChangesis called during a
                                     Update.
Container(inherited from Component)  Gets the IContainerthat contains
                                     the Component.
ContinueUpdateOnError(inherited      Gets or sets a value that specifies
from DataAdapter)                    whether to generate an exception
                                     when an error is encountered during
                                     a row update.
*Note DeleteCommand:                 Overloaded.
connector-net-ref-mysqlclient-mysqldataadapter-deletecommand1.
FillLoadOption(inherited from        Gets or sets the LoadOptionthat
DataAdapter)                         determines how the adapter fills the
                                     DataTablefrom the DbDataReader.
*Note InsertCommand:                 Overloaded.
connector-net-ref-mysqlclient-mysqldataadapter-insertcommand1.
MissingMappingAction(inherited from  Determines the action to take when
DataAdapter)                         incoming data does not have a
                                     matching table or column.
MissingSchemaAction(inherited from   Determines the action to take when
DataAdapter)                         existing DataSetschema does not
                                     match incoming data.
ReturnProviderSpecificTypes(inheritedGets or sets whether the Fillmethod
from DataAdapter)                    should return provider-specific
                                     values or common CLS-compliant
                                     values.
*Note SelectCommand:                 Overloaded.
connector-net-ref-mysqlclient-mysqldataadapter-selectcommand1.
Site(inherited from Component)       Gets or sets the ISiteof the
                                     Component.
TableMappings(inherited from         Gets a collection that provides the
DataAdapter)                         master mapping between a source
                                     table and a DataTable.
UpdateBatchSize(inherited from       Gets or sets a value that enables
DbDataAdapter)                       or disables batch processing
                                     support, and specifies the number
                                     of commands that can be executed in
                                     a batch.
*Note UpdateCommand:                 Overloaded.
connector-net-ref-mysqlclient-mysqldataadapter-updatecommand1.

*Public Instance Methods*

CreateObjRef(inherited from          Creates an object that contains all
MarshalByRefObject)                  the relevant information required to
                                     generate a proxy used to
                                     communicate with a remote object.
Dispose(inherited from Component)    Releases all resources used by the
                                     Component.
Equals(inherited from Object)        Determines whether the specified
                                     Objectis equal to the current
                                     Object.
Fill(inherited from DbDataAdapter)   Overloaded. Adds or refreshes rows
                                     in the DataSetto match those in the
                                     data source using the DataSetname,
                                     and creates a DataTablenamed
                                     "Table."
FillSchema(inherited from            Overloaded. Configures the schema
DbDataAdapter)                       of the specified DataTablebased on
                                     the specified SchemaType.
GetFillParameters(inherited from     Gets the parameters set by the user
DbDataAdapter)                       when executing an SQL *Note
                                     `SELECT': select.  statement.
GetHashCode(inherited from Object)   Serves as a hash function for a
                                     particular type. GetHashCodeis
                                     suitable for use in hashing
                                     algorithms and data structures like
                                     a hash table.
GetLifetimeService(inherited from    Retrieves the current lifetime
MarshalByRefObject)                  service object that controls the
                                     lifetime policy for this instance.
GetType(inherited from Object)       Gets the Typeof the current
                                     instance.
InitializeLifetimeService(inherited  Obtains a lifetime service object
from MarshalByRefObject)             to control the lifetime policy for
                                     this instance.
ResetFillLoadOption(inherited from   Resets FillLoadOptionto its default
DataAdapter)                         state and causes Fillto honor
                                     AcceptChangesDuringFill.
ShouldSerializeAcceptChangesDuringFill(inheritedDetermines whether the
from DataAdapter)                    AcceptChangesDuringFillproperty
                                     should be persisted.
ShouldSerializeFillLoadOption(inheritedDetermines whether the
from DataAdapter)                    FillLoadOptionproperty should be
                                     persisted.
ToString(inherited from Component)   Returns a Stringcontaining the name
                                     of the Component, if any. This
                                     method should not be overridden.
Update(inherited from DbDataAdapter) Overloaded. Calls the respective
                                     INSERT, UPDATE, or DELETE statements
                                     for each inserted, updated, or
                                     deleted row in the specified
                                     DataSet.

*Public Instance Events*

Disposed(inherited from Component)   Adds an event handler to listen to
                                     the Disposedevent on the component.
FillError(inherited from             Returned when an error occurs
DataAdapter)                         during a fill operation.
*Note RowUpdated:                    Occurs during Update after a
connector-net-ref-mysqlclient-mysqldataadapter-rowupdated.command is executed against the data
                                     source. The attempt to update is
                                     made, so the event fires.
*Note RowUpdating:                   Occurs during Update before a
connector-net-ref-mysqlclient-mysqldataadapter-rowupdating.command is executed against the data
                                     source. The attempt to update is
                                     made, so the event fires.

*Protected Internal Instance Properties*

FillCommandBehavior(inherited from   Gets or sets the behavior of the
DbDataAdapter)                       command used to fill the data
                                     adapter.

*See Also*

*Note MySqlDataAdapter Class:
connector-net-ref-mysqlclient-mysqldataadapter, *Note
MySql.Data.MySqlClient Namespace: connector-net-ref-mysqlclient.


File: manual.info,  Node: connector-net-ref-mysqlclient-mysqldataadapterconstructor,  Next: connector-net-ref-mysqlclient-mysqldataadapter-deletecommand1,  Prev: connector-net-ref-mysqlclient-mysqldataadaptermembers,  Up: connector-net-ref-mysqlclient-mysqldataadaptermembers

20.2.7.166 `MySqlDataAdapter' Constructor
.........................................

* Menu:

* connector-net-ref-mysqlclient-mysqldataadapterconstructor1::  `MySqlDataAdapter' Constructor
* connector-net-ref-mysqlclient-mysqldataadapterconstructor2::  `MySqlDataAdapter' Constructor
* connector-net-ref-mysqlclient-mysqldataadapterconstructor3::  `MySqlDataAdapter' Constructor
* connector-net-ref-mysqlclient-mysqldataadapterconstructor4::  `MySqlDataAdapter' Constructor

Initializes a new instance of the *Note MySqlDataAdapter:
connector-net-ref-mysqlclient-mysqldataadapter.  class.

*Overload List*

Initializes a new instance of the *Note MySqlDataAdapter:
connector-net-ref-mysqlclient-mysqldataadapter.  class.

   * *Note public MySqlDataAdapter();:
     connector-net-ref-mysqlclient-mysqldataadapterconstructor1.

   * *Note public MySqlDataAdapter(MySqlCommand);:
     connector-net-ref-mysqlclient-mysqldataadapterconstructor2.

   * *Note public MySqlDataAdapter(string:
     (MySqlConnection);)connector-net-ref-mysqlclient-mysqldataadapterconstructor3.

   * *Note public MySqlDataAdapter(string:
     (string);)connector-net-ref-mysqlclient-mysqldataadapterconstructor4.

*See Also*

*Note MySqlDataAdapter Class:
connector-net-ref-mysqlclient-mysqldataadapter, *Note
MySql.Data.MySqlClient Namespace: connector-net-ref-mysqlclient.


File: manual.info,  Node: connector-net-ref-mysqlclient-mysqldataadapterconstructor1,  Next: connector-net-ref-mysqlclient-mysqldataadapterconstructor2,  Prev: connector-net-ref-mysqlclient-mysqldataadapterconstructor,  Up: connector-net-ref-mysqlclient-mysqldataadapterconstructor

20.2.7.167 `MySqlDataAdapter' Constructor
.........................................

Initializes a new instance of the *Note MySqlDataAdapter:
connector-net-ref-mysqlclient-mysqldataadapter.  class.

*Syntax: Visual Basic*

     Overloads Public Sub New()

*Syntax: C#*

     public MySqlDataAdapter();

*See Also*

*Note MySqlDataAdapter Class:
connector-net-ref-mysqlclient-mysqldataadapter, *Note
MySql.Data.MySqlClient Namespace: connector-net-ref-mysqlclient, *Note
MySqlDataAdapter Constructor Overload List:
connector-net-ref-mysqlclient-mysqldataadapterconstructor.


File: manual.info,  Node: connector-net-ref-mysqlclient-mysqldataadapterconstructor2,  Next: connector-net-ref-mysqlclient-mysqldataadapterconstructor3,  Prev: connector-net-ref-mysqlclient-mysqldataadapterconstructor1,  Up: connector-net-ref-mysqlclient-mysqldataadapterconstructor

20.2.7.168 `MySqlDataAdapter' Constructor
.........................................

*Syntax: Visual Basic*

     Overloads Public Sub New( _
        ByVal selectCommand As MySqlCommand _
     )

*Syntax: C#*

     public MySqlDataAdapter(
     MySqlCommandselectCommand
     );

*See Also*

*Note MySqlDataAdapter Class:
connector-net-ref-mysqlclient-mysqldataadapter, *Note
MySql.Data.MySqlClient Namespace: connector-net-ref-mysqlclient, *Note
MySqlDataAdapter Constructor Overload List:
connector-net-ref-mysqlclient-mysqldataadapterconstructor.


File: manual.info,  Node: connector-net-ref-mysqlclient-mysqldataadapterconstructor3,  Next: connector-net-ref-mysqlclient-mysqldataadapterconstructor4,  Prev: connector-net-ref-mysqlclient-mysqldataadapterconstructor2,  Up: connector-net-ref-mysqlclient-mysqldataadapterconstructor

20.2.7.169 `MySqlDataAdapter' Constructor
.........................................

*Syntax: Visual Basic*

     Overloads Public Sub New( _
        ByVal selectCommandText As String, _
        ByVal connection As MySqlConnection _
     )

*Syntax: C#*

     public MySqlDataAdapter(
     stringselectCommandText,
     MySqlConnectionconnection
     );

*See Also*

*Note MySqlDataAdapter Class:
connector-net-ref-mysqlclient-mysqldataadapter, *Note
MySql.Data.MySqlClient Namespace: connector-net-ref-mysqlclient, *Note
MySqlDataAdapter Constructor Overload List:
connector-net-ref-mysqlclient-mysqldataadapterconstructor.


File: manual.info,  Node: connector-net-ref-mysqlclient-mysqldataadapterconstructor4,  Prev: connector-net-ref-mysqlclient-mysqldataadapterconstructor3,  Up: connector-net-ref-mysqlclient-mysqldataadapterconstructor

20.2.7.170 `MySqlDataAdapter' Constructor
.........................................

*Syntax: Visual Basic*

     Overloads Public Sub New( _
        ByVal selectCommandText As String, _
        ByVal selectConnString As String _
     )

*Syntax: C#*

     public MySqlDataAdapter(
     stringselectCommandText,
     stringselectConnString
     );

*See Also*

*Note MySqlDataAdapter Class:
connector-net-ref-mysqlclient-mysqldataadapter, *Note
MySql.Data.MySqlClient Namespace: connector-net-ref-mysqlclient, *Note
MySqlDataAdapter Constructor Overload List:
connector-net-ref-mysqlclient-mysqldataadapterconstructor.


File: manual.info,  Node: connector-net-ref-mysqlclient-mysqldataadapter-deletecommand1,  Next: connector-net-ref-mysqlclient-mysqldataadapter-insertcommand1,  Prev: connector-net-ref-mysqlclient-mysqldataadapterconstructor,  Up: connector-net-ref-mysqlclient-mysqldataadaptermembers

20.2.7.171 DeleteCommand Property
.................................

*Syntax: Visual Basic*

     Overloads Public Property DeleteCommand As MySqlCommand

*Syntax: C#*

     new public MySqlCommand DeleteCommand {get; set;}

*See Also*

*Note MySqlDataAdapter Class:
connector-net-ref-mysqlclient-mysqldataadapter, *Note
MySql.Data.MySqlClient Namespace: connector-net-ref-mysqlclient.


File: manual.info,  Node: connector-net-ref-mysqlclient-mysqldataadapter-insertcommand1,  Next: connector-net-ref-mysqlclient-mysqldataadapter-selectcommand1,  Prev: connector-net-ref-mysqlclient-mysqldataadapter-deletecommand1,  Up: connector-net-ref-mysqlclient-mysqldataadaptermembers

20.2.7.172 InsertCommand Property
.................................

*Syntax: Visual Basic*

     Overloads Public Property InsertCommand As MySqlCommand

*Syntax: C#*

     new public MySqlCommand InsertCommand {get; set;}

*See Also*

*Note MySqlDataAdapter Class:
connector-net-ref-mysqlclient-mysqldataadapter, *Note
MySql.Data.MySqlClient Namespace: connector-net-ref-mysqlclient.


File: manual.info,  Node: connector-net-ref-mysqlclient-mysqldataadapter-selectcommand1,  Next: connector-net-ref-mysqlclient-mysqldataadapter-updatecommand1,  Prev: connector-net-ref-mysqlclient-mysqldataadapter-insertcommand1,  Up: connector-net-ref-mysqlclient-mysqldataadaptermembers

20.2.7.173 SelectCommand Property
.................................

*Syntax: Visual Basic*

     Overloads Public Property SelectCommand As MySqlCommand

*Syntax: C#*

     new public MySqlCommand SelectCommand {get; set;}

*See Also*

*Note MySqlDataAdapter Class:
connector-net-ref-mysqlclient-mysqldataadapter, *Note
MySql.Data.MySqlClient Namespace: connector-net-ref-mysqlclient.


File: manual.info,  Node: connector-net-ref-mysqlclient-mysqldataadapter-updatecommand1,  Next: connector-net-ref-mysqlclient-mysqldataadapter-rowupdated,  Prev: connector-net-ref-mysqlclient-mysqldataadapter-selectcommand1,  Up: connector-net-ref-mysqlclient-mysqldataadaptermembers

20.2.7.174 UpdateCommand Property
.................................

*Syntax: Visual Basic*

     Overloads Public Property UpdateCommand As MySqlCommand

*Syntax: C#*

     new public MySqlCommand UpdateCommand {get; set;}

*See Also*

*Note MySqlDataAdapter Class:
connector-net-ref-mysqlclient-mysqldataadapter, *Note
MySql.Data.MySqlClient Namespace: connector-net-ref-mysqlclient.


File: manual.info,  Node: connector-net-ref-mysqlclient-mysqldataadapter-rowupdated,  Next: connector-net-ref-mysqlclient-mysqldataadapter-rowupdating,  Prev: connector-net-ref-mysqlclient-mysqldataadapter-updatecommand1,  Up: connector-net-ref-mysqlclient-mysqldataadaptermembers

20.2.7.175 `MySqlDataAdapter.RowUpdated' Event
..............................................

* Menu:

* connector-net-ref-mysqlclient-mysqlrowupdatedeventhandler::  `MySqlRowUpdatedEventHandler' Delegate

Occurs during Update after a command is executed against the data
source. The attempt to update is made, so the event fires.

*Syntax: Visual Basic*

     Public Event RowUpdated As MySqlRowUpdatedEventHandler

*Syntax: C#*

     public event MySqlRowUpdatedEventHandler RowUpdated;

*Event Data*

The event handler receives an argument of type *Note
MySqlRowUpdatedEventArgs:
connector-net-ref-mysqlclient-mysqlrowupdatedeventargs.  containing
data related to this event. The following
MySqlRowUpdatedEventArgsproperties provide information specific to this
event.

*Property*                           *Description*
*Note Command:                       Gets or sets the MySqlCommand
connector-net-ref-mysqlclient-mysqlrowupdatedeventargs-command1.executed when Update is called.
Errors                               Gets any errors generated by the
                                     .NET Framework data provider when
                                     the Commandwas executed.
RecordsAffected                      Gets the number of rows changed,
                                     inserted, or deleted by execution of
                                     the SQL statement.
Row                                  Gets the DataRowsent through an
                                     Update.
RowCount                             Gets the number of rows processed
                                     in a batch of updated records.
StatementType                        Gets the type of SQL statement
                                     executed.
Status                               Gets the UpdateStatusof the
                                     Commandproperty.
TableMapping                         Gets the DataTableMappingsent
                                     through an Update.

*See Also*

*Note MySqlDataAdapter Class:
connector-net-ref-mysqlclient-mysqldataadapter, *Note
MySql.Data.MySqlClient Namespace: connector-net-ref-mysqlclient.


File: manual.info,  Node: connector-net-ref-mysqlclient-mysqlrowupdatedeventhandler,  Prev: connector-net-ref-mysqlclient-mysqldataadapter-rowupdated,  Up: connector-net-ref-mysqlclient-mysqldataadapter-rowupdated

20.2.7.176 `MySqlRowUpdatedEventHandler' Delegate
.................................................

* Menu:

* connector-net-ref-mysqlclient-mysqlrowupdatedeventargs::  `MySqlRowUpdatedEventArgs' Class

Represents the method that will handle the RowUpdatedevent of a *Note
MySqlDataAdapter: connector-net-ref-mysqlclient-mysqldataadapter .

*Syntax: Visual Basic*

     Public Delegate Sub MySqlRowUpdatedEventHandler( _
        ByVal sender As Object, _
        ByVal e As MySqlRowUpdatedEventArgs _
     )

*Syntax: C#*

     public delegate void MySqlRowUpdatedEventHandler(
     objectsender,
     MySqlRowUpdatedEventArgse
     );

*Requirements*

Namespace: *Note MySql.Data.MySqlClient: connector-net-ref-mysqlclient.

Assembly: MySql.Data (in MySql.Data.dll)

*See Also*

*Note MySql.Data.MySqlClient Namespace: connector-net-ref-mysqlclient.


File: manual.info,  Node: connector-net-ref-mysqlclient-mysqlrowupdatedeventargs,  Prev: connector-net-ref-mysqlclient-mysqlrowupdatedeventhandler,  Up: connector-net-ref-mysqlclient-mysqlrowupdatedeventhandler

20.2.7.177 `MySqlRowUpdatedEventArgs' Class
...........................................

* Menu:

* connector-net-ref-mysqlclient-mysqlrowupdatedeventargsmembers::  `MySqlRowUpdatedEventArgs' Members

Provides data for the RowUpdated event. This class cannot be inherited.

For a list of all members of this type, see *Note
MySqlRowUpdatedEventArgs Members:
connector-net-ref-mysqlclient-mysqlrowupdatedeventargsmembers .

*Syntax: Visual Basic*

     NotInheritable Public Class MySqlRowUpdatedEventArgs_
       Inherits RowUpdatedEventArgs

*Syntax: C#*

     public sealed class MySqlRowUpdatedEventArgs : RowUpdatedEventArgs

*Thread Safety*

Public static (Sharedin Visual Basic) members of this type are safe for
multithreaded operations.  Instance members are notguaranteed to be
thread-safe.

*Requirements*

Namespace: *Note MySql.Data.MySqlClient: connector-net-ref-mysqlclient.

Assembly: MySql.Data (in MySql.Data.dll)

*See Also*

*Note MySqlRowUpdatedEventArgs Members:
connector-net-ref-mysqlclient-mysqlrowupdatedeventargsmembers, *Note
MySql.Data.MySqlClient Namespace: connector-net-ref-mysqlclient.


File: manual.info,  Node: connector-net-ref-mysqlclient-mysqlrowupdatedeventargsmembers,  Prev: connector-net-ref-mysqlclient-mysqlrowupdatedeventargs,  Up: connector-net-ref-mysqlclient-mysqlrowupdatedeventargs

20.2.7.178 `MySqlRowUpdatedEventArgs' Members
.............................................

* Menu:

* connector-net-ref-mysqlclient-mysqlrowupdatedeventargsconstructor::  `MySqlRowUpdatedEventArgs' Constructor
* connector-net-ref-mysqlclient-mysqlrowupdatedeventargs-command1::  Command Property

*Note MySqlRowUpdatedEventArgs overview:
connector-net-ref-mysqlclient-mysqlrowupdatedeventargs.

*Public Instance Constructors*

*Note MySqlRowUpdatedEventArgs       Initializes a new instance of the
Constructor:                         MySqlRowUpdatedEventArgs class.
connector-net-ref-mysqlclient-mysqlrowupdatedeventargsconstructor.

*Public Instance Properties*

*Note Command:                       Overloaded. Gets or sets the
connector-net-ref-mysqlclient-mysqlrowupdatedeventargs-command1.MySqlCommand executed when Update is
                                     called.
Errors(inherited from                Gets any errors generated by the
RowUpdatedEventArgs)                 .NET Framework data provider when
                                     the Commandwas executed.
RecordsAffected(inherited from       Gets the number of rows changed,
RowUpdatedEventArgs)                 inserted, or deleted by execution of
                                     the SQL statement.
Row(inherited from                   Gets the DataRowsent through an
RowUpdatedEventArgs)                 Update.
RowCount(inherited from              Gets the number of rows processed
RowUpdatedEventArgs)                 in a batch of updated records.
StatementType(inherited from         Gets the type of SQL statement
RowUpdatedEventArgs)                 executed.
Status(inherited from                Gets the UpdateStatusof the
RowUpdatedEventArgs)                 Commandproperty.
TableMapping(inherited from          Gets the DataTableMappingsent
RowUpdatedEventArgs)                 through an Update.

*Public Instance Methods*

CopyToRows(inherited from            Overloaded. Copies references to
RowUpdatedEventArgs)                 the modified rows into the provided
                                     array.
Equals(inherited from Object)        Determines whether the specified
                                     Objectis equal to the current
                                     Object.
GetHashCode(inherited from Object)   Serves as a hash function for a
                                     particular type. GetHashCodeis
                                     suitable for use in hashing
                                     algorithms and data structures like
                                     a hash table.
GetType(inherited from Object)       Gets the Typeof the current
                                     instance.
ToString(inherited from Object)      Returns a Stringthat represents the
                                     current Object.

*See Also*

*Note MySqlRowUpdatedEventArgs Class:
connector-net-ref-mysqlclient-mysqlrowupdatedeventargs, *Note
MySql.Data.MySqlClient Namespace: connector-net-ref-mysqlclient.


File: manual.info,  Node: connector-net-ref-mysqlclient-mysqlrowupdatedeventargsconstructor,  Next: connector-net-ref-mysqlclient-mysqlrowupdatedeventargs-command1,  Prev: connector-net-ref-mysqlclient-mysqlrowupdatedeventargsmembers,  Up: connector-net-ref-mysqlclient-mysqlrowupdatedeventargsmembers

20.2.7.179 `MySqlRowUpdatedEventArgs' Constructor
.................................................

Initializes a new instance of the MySqlRowUpdatedEventArgs class.

*Syntax: Visual Basic*

     Public Sub New( _
        ByVal row As DataRow, _
        ByVal command As IDbCommand, _
        ByVal statementType As StatementType, _
        ByVal tableMapping As DataTableMapping _
     )

*Syntax: C#*

     public MySqlRowUpdatedEventArgs(
     DataRowrow,
     IDbCommandcommand,
     StatementTypestatementType,
     DataTableMappingtableMapping
     );

*Parameters*

   * `row': The DataRowsent through an Update.

   * `command': The IDbCommandexecuted when Updateis called.

   * `statementType': One of the StatementTypevalues that specifies the
     type of query executed.

   * `tableMapping': The DataTableMappingsent through an Update.

*See Also*

*Note MySqlRowUpdatedEventArgs Class:
connector-net-ref-mysqlclient-mysqlrowupdatedeventargs, *Note
MySql.Data.MySqlClient Namespace: connector-net-ref-mysqlclient.


File: manual.info,  Node: connector-net-ref-mysqlclient-mysqlrowupdatedeventargs-command1,  Prev: connector-net-ref-mysqlclient-mysqlrowupdatedeventargsconstructor,  Up: connector-net-ref-mysqlclient-mysqlrowupdatedeventargsmembers

20.2.7.180 Command Property
...........................

Gets or sets the MySqlCommand executed when Update is called.

*Syntax: Visual Basic*

     Overloads Public ReadOnly Property Command As MySqlCommand

*Syntax: C#*

     new public MySqlCommand Command {get;}

*See Also*

*Note MySqlRowUpdatedEventArgs Class:
connector-net-ref-mysqlclient-mysqlrowupdatedeventargs, *Note
MySql.Data.MySqlClient Namespace: connector-net-ref-mysqlclient.


File: manual.info,  Node: connector-net-ref-mysqlclient-mysqldataadapter-rowupdating,  Prev: connector-net-ref-mysqlclient-mysqldataadapter-rowupdated,  Up: connector-net-ref-mysqlclient-mysqldataadaptermembers

20.2.7.181 `MySqlDataAdapter.RowUpdating' Event
...............................................

* Menu:

* connector-net-ref-mysqlclient-mysqlrowupdatingeventhandler::  `MySqlRowUpdatingEventHandler' Delegate

Occurs during Update before a command is executed against the data
source. The attempt to update is made, so the event fires.

*Syntax: Visual Basic*

     Public Event RowUpdating As MySqlRowUpdatingEventHandler

*Syntax: C#*

     public event MySqlRowUpdatingEventHandler RowUpdating;

*Event Data*

The event handler receives an argument of type *Note
MySqlRowUpdatingEventArgs:
connector-net-ref-mysqlclient-mysqlrowupdatingeventargs.  containing
data related to this event. The following
MySqlRowUpdatingEventArgsproperties provide information specific to
this event.

*Property*                           *Description*
*Note Command:                       Gets or sets the MySqlCommand to
connector-net-ref-mysqlclient-mysqlrowupdatingeventargs-command1.execute when performing the Update.
Errors                               Gets any errors generated by the
                                     .NET Framework data provider when
                                     the Commandexecutes.
Row                                  Gets the DataRowthat will be sent
                                     to the server as part of an insert,
                                     update, or delete operation.
StatementType                        Gets the type of SQL statement to
                                     execute.
Status                               Gets or sets the UpdateStatusof the
                                     Commandproperty.
TableMapping                         Gets the DataTableMappingto send
                                     through the Update.

*See Also*

*Note MySqlDataAdapter Class:
connector-net-ref-mysqlclient-mysqldataadapter, *Note
MySql.Data.MySqlClient Namespace: connector-net-ref-mysqlclient.


File: manual.info,  Node: connector-net-ref-mysqlclient-mysqlrowupdatingeventhandler,  Prev: connector-net-ref-mysqlclient-mysqldataadapter-rowupdating,  Up: connector-net-ref-mysqlclient-mysqldataadapter-rowupdating

20.2.7.182 `MySqlRowUpdatingEventHandler' Delegate
..................................................

* Menu:

* connector-net-ref-mysqlclient-mysqlrowupdatingeventargs::  `MySqlRowUpdatingEventArgs' Class

Represents the method that will handle the RowUpdatingevent of a *Note
MySqlDataAdapter: connector-net-ref-mysqlclient-mysqldataadapter .

*Syntax: Visual Basic*

     Public Delegate Sub MySqlRowUpdatingEventHandler( _
        ByVal sender As Object, _
        ByVal e As MySqlRowUpdatingEventArgs _
     )

*Syntax: C#*

     public delegate void MySqlRowUpdatingEventHandler(
     objectsender,
     MySqlRowUpdatingEventArgse
     );

*Requirements*

Namespace: *Note MySql.Data.MySqlClient: connector-net-ref-mysqlclient.

Assembly: MySql.Data (in MySql.Data.dll)

*See Also*

*Note MySql.Data.MySqlClient Namespace: connector-net-ref-mysqlclient.


File: manual.info,  Node: connector-net-ref-mysqlclient-mysqlrowupdatingeventargs,  Prev: connector-net-ref-mysqlclient-mysqlrowupdatingeventhandler,  Up: connector-net-ref-mysqlclient-mysqlrowupdatingeventhandler

20.2.7.183 `MySqlRowUpdatingEventArgs' Class
............................................

* Menu:

* connector-net-ref-mysqlclient-mysqlrowupdatingeventargsmembers::  `MySqlRowUpdatingEventArgs' Members

Provides data for the RowUpdating event. This class cannot be inherited.

For a list of all members of this type, see *Note
MySqlRowUpdatingEventArgs Members:
connector-net-ref-mysqlclient-mysqlrowupdatingeventargsmembers .

*Syntax: Visual Basic*

     NotInheritable Public Class MySqlRowUpdatingEventArgs_
       Inherits RowUpdatingEventArgs

*Syntax: C#*

     public sealed class MySqlRowUpdatingEventArgs : RowUpdatingEventArgs

*Thread Safety*

Public static (Sharedin Visual Basic) members of this type are safe for
multithreaded operations.  Instance members are notguaranteed to be
thread-safe.

*Requirements*

Namespace: *Note MySql.Data.MySqlClient: connector-net-ref-mysqlclient.

Assembly: MySql.Data (in MySql.Data.dll)

*See Also*

*Note MySqlRowUpdatingEventArgs Members:
connector-net-ref-mysqlclient-mysqlrowupdatingeventargsmembers, *Note
MySql.Data.MySqlClient Namespace: connector-net-ref-mysqlclient.


File: manual.info,  Node: connector-net-ref-mysqlclient-mysqlrowupdatingeventargsmembers,  Prev: connector-net-ref-mysqlclient-mysqlrowupdatingeventargs,  Up: connector-net-ref-mysqlclient-mysqlrowupdatingeventargs

20.2.7.184 `MySqlRowUpdatingEventArgs' Members
..............................................

* Menu:

* connector-net-ref-mysqlclient-mysqlrowupdatingeventargsconstructor::  `MySqlRowUpdatingEventArgs' Constructor
* connector-net-ref-mysqlclient-mysqlrowupdatingeventargs-command1::  Command Property

*Note MySqlRowUpdatingEventArgs overview:
connector-net-ref-mysqlclient-mysqlrowupdatingeventargs.

*Public Instance Constructors*

*Note MySqlRowUpdatingEventArgs      Initializes a new instance of the
Constructor:                         MySqlRowUpdatingEventArgs class.
connector-net-ref-mysqlclient-mysqlrowupdatingeventargsconstructor.

*Public Instance Properties*

*Note Command:                       Overloaded. Gets or sets the
connector-net-ref-mysqlclient-mysqlrowupdatingeventargs-command1.MySqlCommand to execute when
                                     performing the Update.
Errors(inherited from                Gets any errors generated by the
RowUpdatingEventArgs)                .NET Framework data provider when
                                     the Commandexecutes.
Row(inherited from                   Gets the DataRowthat will be sent
RowUpdatingEventArgs)                to the server as part of an insert,
                                     update, or delete operation.
StatementType(inherited from         Gets the type of SQL statement to
RowUpdatingEventArgs)                execute.
Status(inherited from                Gets or sets the UpdateStatusof the
RowUpdatingEventArgs)                Commandproperty.
TableMapping(inherited from          Gets the DataTableMappingto send
RowUpdatingEventArgs)                through the Update.

*Public Instance Methods*

Equals(inherited from Object)        Determines whether the specified
                                     Objectis equal to the current
                                     Object.
GetHashCode(inherited from Object)   Serves as a hash function for a
                                     particular type. GetHashCodeis
                                     suitable for use in hashing
                                     algorithms and data structures like
                                     a hash table.
GetType(inherited from Object)       Gets the Typeof the current
                                     instance.
ToString(inherited from Object)      Returns a Stringthat represents the
                                     current Object.

*See Also*

*Note MySqlRowUpdatingEventArgs Class:
connector-net-ref-mysqlclient-mysqlrowupdatingeventargs, *Note
MySql.Data.MySqlClient Namespace: connector-net-ref-mysqlclient.


File: manual.info,  Node: connector-net-ref-mysqlclient-mysqlrowupdatingeventargsconstructor,  Next: connector-net-ref-mysqlclient-mysqlrowupdatingeventargs-command1,  Prev: connector-net-ref-mysqlclient-mysqlrowupdatingeventargsmembers,  Up: connector-net-ref-mysqlclient-mysqlrowupdatingeventargsmembers

20.2.7.185 `MySqlRowUpdatingEventArgs' Constructor
..................................................

Initializes a new instance of the MySqlRowUpdatingEventArgs class.

*Syntax: Visual Basic*

     Public Sub New( _
        ByVal row As DataRow, _
        ByVal command As IDbCommand, _
        ByVal statementType As StatementType, _
        ByVal tableMapping As DataTableMapping _
     )

*Syntax: C#*

     public MySqlRowUpdatingEventArgs(
     DataRowrow,
     IDbCommandcommand,
     StatementTypestatementType,
     DataTableMappingtableMapping
     );

*Parameters*

   * `row': The DataRowto Update.

   * `command': The IDbCommandto execute during Update.

   * `statementType': One of the StatementTypevalues that specifies the
     type of query executed.

   * `tableMapping': The DataTableMappingsent through an Update.

*See Also*

*Note MySqlRowUpdatingEventArgs Class:
connector-net-ref-mysqlclient-mysqlrowupdatingeventargs, *Note
MySql.Data.MySqlClient Namespace: connector-net-ref-mysqlclient.


File: manual.info,  Node: connector-net-ref-mysqlclient-mysqlrowupdatingeventargs-command1,  Prev: connector-net-ref-mysqlclient-mysqlrowupdatingeventargsconstructor,  Up: connector-net-ref-mysqlclient-mysqlrowupdatingeventargsmembers

20.2.7.186 Command Property
...........................

Gets or sets the MySqlCommand to execute when performing the Update.

*Syntax: Visual Basic*

     Overloads Public Property Command As MySqlCommand

*Syntax: C#*

     new public MySqlCommand Command {get; set;}

*See Also*

*Note MySqlRowUpdatingEventArgs Class:
connector-net-ref-mysqlclient-mysqlrowupdatingeventargs, *Note
MySql.Data.MySqlClient Namespace: connector-net-ref-mysqlclient.


File: manual.info,  Node: connector-net-ref-mysqlclient-mysqlcommandbuilderconstructor4,  Next: connector-net-ref-mysqlclient-mysqlcommandbuilderconstructor2,  Prev: connector-net-ref-mysqlclient-mysqlcommandbuilderconstructor3,  Up: connector-net-ref-mysqlclient-mysqlcommandbuilderconstructor

20.2.7.187 `MySqlCommandBuilder' Constructor
............................................

*Syntax: Visual Basic*

     Overloads Public Sub New( _
        ByVal adapter As MySqlDataAdapter, _
        ByVal lastOneWins As Boolean _
     )

*Syntax: C#*

     public MySqlCommandBuilder(
     MySqlDataAdapteradapter,
     boollastOneWins
     );

*See Also*

*Note MySqlCommandBuilder Class:
connector-net-ref-mysqlclient-mysqlcommandbuilder, *Note
MySql.Data.MySqlClient Namespace: connector-net-ref-mysqlclient, *Note
MySqlCommandBuilder Constructor Overload List:
connector-net-ref-mysqlclient-mysqlcommandbuilderconstructor.


File: manual.info,  Node: connector-net-ref-mysqlclient-mysqlcommandbuilderconstructor2,  Prev: connector-net-ref-mysqlclient-mysqlcommandbuilderconstructor4,  Up: connector-net-ref-mysqlclient-mysqlcommandbuilderconstructor

20.2.7.188 `MySqlCommandBuilder' Constructor
............................................

*Syntax: Visual Basic*

     Overloads Public Sub New( _
        ByVal lastOneWins As Boolean _
     )

*Syntax: C#*

     public MySqlCommandBuilder(
     boollastOneWins
     );

*See Also*

*Note MySqlCommandBuilder Class:
connector-net-ref-mysqlclient-mysqlcommandbuilder, *Note
MySql.Data.MySqlClient Namespace: connector-net-ref-mysqlclient, *Note
MySqlCommandBuilder Constructor Overload List:
connector-net-ref-mysqlclient-mysqlcommandbuilderconstructor.


File: manual.info,  Node: connector-net-ref-mysqlclient-mysqlcommandbuilder-dataadapter,  Next: connector-net-ref-mysqlclient-mysqlcommandbuilder-quoteprefix,  Prev: connector-net-ref-mysqlclient-mysqlcommandbuilderconstructor,  Up: connector-net-ref-mysqlclient-mysqlcommandbuildermembers

20.2.7.189 DataAdapter Property
...............................

*Syntax: Visual Basic*

     Public Property DataAdapter As MySqlDataAdapter

*Syntax: C#*

     public MySqlDataAdapter DataAdapter {get; set;}

*See Also*

*Note MySqlCommandBuilder Class:
connector-net-ref-mysqlclient-mysqlcommandbuilder, *Note
MySql.Data.MySqlClient Namespace: connector-net-ref-mysqlclient.


File: manual.info,  Node: connector-net-ref-mysqlclient-mysqlcommandbuilder-quoteprefix,  Next: connector-net-ref-mysqlclient-mysqlcommandbuilder-quotesuffix,  Prev: connector-net-ref-mysqlclient-mysqlcommandbuilder-dataadapter,  Up: connector-net-ref-mysqlclient-mysqlcommandbuildermembers

20.2.7.190 QuotePrefix Property
...............................

*Syntax: Visual Basic*

     Public Property QuotePrefix As String

*Syntax: C#*

     public string QuotePrefix {get; set;}

*See Also*

*Note MySqlCommandBuilder Class:
connector-net-ref-mysqlclient-mysqlcommandbuilder, *Note
MySql.Data.MySqlClient Namespace: connector-net-ref-mysqlclient.


File: manual.info,  Node: connector-net-ref-mysqlclient-mysqlcommandbuilder-quotesuffix,  Next: connector-net-ref-mysqlclient-mysqlcommandbuilder-getdeletecommand,  Prev: connector-net-ref-mysqlclient-mysqlcommandbuilder-quoteprefix,  Up: connector-net-ref-mysqlclient-mysqlcommandbuildermembers

20.2.7.191 QuoteSuffix Property
...............................

*Syntax: Visual Basic*

     Public Property QuoteSuffix As String

*Syntax: C#*

     public string QuoteSuffix {get; set;}

*See Also*

*Note MySqlCommandBuilder Class:
connector-net-ref-mysqlclient-mysqlcommandbuilder, *Note
MySql.Data.MySqlClient Namespace: connector-net-ref-mysqlclient.


File: manual.info,  Node: connector-net-ref-mysqlclient-mysqlcommandbuilder-getdeletecommand,  Next: connector-net-ref-mysqlclient-mysqlcommandbuilder-getinsertcommand,  Prev: connector-net-ref-mysqlclient-mysqlcommandbuilder-quotesuffix,  Up: connector-net-ref-mysqlclient-mysqlcommandbuildermembers

20.2.7.192 `MySqlCommandBuilder.GetDeleteCommand' Method
........................................................

*Syntax: Visual Basic*

     Public Function GetDeleteCommand() As MySqlCommand

*Syntax: C#*

     public MySqlCommand GetDeleteCommand();

*See Also*

*Note MySqlCommandBuilder Class:
connector-net-ref-mysqlclient-mysqlcommandbuilder, *Note
MySql.Data.MySqlClient Namespace: connector-net-ref-mysqlclient.


File: manual.info,  Node: connector-net-ref-mysqlclient-mysqlcommandbuilder-getinsertcommand,  Next: connector-net-ref-mysqlclient-mysqlcommandbuilder-getupdatecommand,  Prev: connector-net-ref-mysqlclient-mysqlcommandbuilder-getdeletecommand,  Up: connector-net-ref-mysqlclient-mysqlcommandbuildermembers

20.2.7.193 `MySqlCommandBuilder.GetInsertCommand' Method
........................................................

*Syntax: Visual Basic*

     Public Function GetInsertCommand() As MySqlCommand

*Syntax: C#*

     public MySqlCommand GetInsertCommand();

*See Also*

*Note MySqlCommandBuilder Class:
connector-net-ref-mysqlclient-mysqlcommandbuilder, *Note
MySql.Data.MySqlClient Namespace: connector-net-ref-mysqlclient.


File: manual.info,  Node: connector-net-ref-mysqlclient-mysqlcommandbuilder-getupdatecommand,  Next: connector-net-ref-mysqlclient-mysqlcommandbuilder-refreshschema,  Prev: connector-net-ref-mysqlclient-mysqlcommandbuilder-getinsertcommand,  Up: connector-net-ref-mysqlclient-mysqlcommandbuildermembers

20.2.7.194 `MySqlCommandBuilder.GetUpdateCommand' Method
........................................................

*Syntax: Visual Basic*

     Public Function GetUpdateCommand() As MySqlCommand

*Syntax: C#*

     public MySqlCommand GetUpdateCommand();

*See Also*

*Note MySqlCommandBuilder Class:
connector-net-ref-mysqlclient-mysqlcommandbuilder, *Note
MySql.Data.MySqlClient Namespace: connector-net-ref-mysqlclient.


File: manual.info,  Node: connector-net-ref-mysqlclient-mysqlcommandbuilder-refreshschema,  Prev: connector-net-ref-mysqlclient-mysqlcommandbuilder-getupdatecommand,  Up: connector-net-ref-mysqlclient-mysqlcommandbuildermembers

20.2.7.195 `MySqlCommandBuilder.RefreshSchema' Method
.....................................................

*Syntax: Visual Basic*

     Public Sub RefreshSchema()

*Syntax: C#*

     public void RefreshSchema();

*See Also*

*Note MySqlCommandBuilder Class:
connector-net-ref-mysqlclient-mysqlcommandbuilder, *Note
MySql.Data.MySqlClient Namespace: connector-net-ref-mysqlclient.


File: manual.info,  Node: connector-net-ref-mysqlclient-mysqlexception,  Next: connector-net-ref-mysqlclient-mysqlhelper,  Prev: connector-net-ref-mysqlclient-mysqlcommandbuilder,  Up: connector-net-ref-mysqlclient

20.2.7.196 `MySqlException' Class
.................................

* Menu:

* connector-net-ref-mysqlclient-mysqlexceptionmembers::  `MySqlException' Members

The exception that is thrown when MySQL returns an error. This class
cannot be inherited.

For a list of all members of this type, see *Note MySqlException
Members: connector-net-ref-mysqlclient-mysqlexceptionmembers .

*Syntax: Visual Basic*

     NotInheritable Public Class MySqlException_
       Inherits SystemException

*Syntax: C#*

     public sealed class MySqlException : SystemException

*Thread Safety*

Public static (Sharedin Visual Basic) members of this type are safe for
multithreaded operations. Instance members are notguaranteed to be
thread-safe.

*Requirements*

Namespace: *Note MySql.Data.MySqlClient: connector-net-ref-mysqlclient.

Assembly: MySql.Data (in MySql.Data.dll)

*See Also*

*Note MySqlException Members:
connector-net-ref-mysqlclient-mysqlexceptionmembers, *Note
MySql.Data.MySqlClient Namespace: connector-net-ref-mysqlclient.


File: manual.info,  Node: connector-net-ref-mysqlclient-mysqlexceptionmembers,  Prev: connector-net-ref-mysqlclient-mysqlexception,  Up: connector-net-ref-mysqlclient-mysqlexception

20.2.7.197 `MySqlException' Members
...................................

* Menu:

* connector-net-ref-mysqlclient-mysqlexception-number::  Number Property

*Note MySqlException overview:
connector-net-ref-mysqlclient-mysqlexception.

*Public Instance Properties*

Data(inherited from Exception)       Gets a collection of key/value
                                     pairs that provide additional,
                                     user-defined information about the
                                     exception.
HelpLink(inherited from Exception)   Gets or sets a link to the help
                                     file associated with this exception.
InnerException(inherited from        Gets the Exceptioninstance that
Exception)                           caused the current exception.
Message(inherited from Exception)    Gets a message that describes the
                                     current exception.
*Note Number:                        Gets a number that identifies the
connector-net-ref-mysqlclient-mysqlexception-number.type of error. This number
                                     corresponds to the error numbers
                                     given in *Note
                                     error-messages-server::.
Source(inherited from Exception)     Gets or sets the name of the
                                     application or the object that
                                     causes the error.
StackTrace(inherited from Exception) Gets a string representation of the
                                     frames on the call stack at the time
                                     the current exception was thrown.
TargetSite(inherited from Exception) Gets the method that throws the
                                     current exception.

*Public Instance Methods*

Equals(inherited from Object)        Determines whether the specified
                                     Objectis equal to the current
                                     Object.
GetBaseException(inherited from      When overridden in a derived class,
Exception)                           returns the Exceptionthat is the
                                     root cause of one or more
                                     subsequent exceptions.
GetHashCode(inherited from Object)   Serves as a hash function for a
                                     particular type. GetHashCodeis
                                     suitable for use in hashing
                                     algorithms and data structures like
                                     a hash table.
GetObjectData(inherited from         When overridden in a derived class,
Exception)                           sets the SerializationInfowith
                                     information about the exception.
GetType(inherited from Exception)    Gets the runtime type of the
                                     current instance.
ToString(inherited from Exception)   Creates and returns a string
                                     representation of the current
                                     exception.

*See Also*

*Note MySqlException Class:
connector-net-ref-mysqlclient-mysqlexception, *Note
MySql.Data.MySqlClient Namespace: connector-net-ref-mysqlclient.


File: manual.info,  Node: connector-net-ref-mysqlclient-mysqlexception-number,  Prev: connector-net-ref-mysqlclient-mysqlexceptionmembers,  Up: connector-net-ref-mysqlclient-mysqlexceptionmembers

20.2.7.198 Number Property
..........................

Gets a number that identifies the type of error.

*Syntax: Visual Basic*

     Public ReadOnly Property Number As Integer

*Syntax: C#*

     public int Number {get;}

*See Also*

*Note MySqlException Class:
connector-net-ref-mysqlclient-mysqlexception, *Note
MySql.Data.MySqlClient Namespace: connector-net-ref-mysqlclient.


File: manual.info,  Node: connector-net-ref-mysqlclient-mysqlhelper,  Next: connector-net-ref-mysqlclient-mysqlerrorcode,  Prev: connector-net-ref-mysqlclient-mysqlexception,  Up: connector-net-ref-mysqlclient

20.2.7.199 `MySqlHelper' Class
..............................

* Menu:

* connector-net-ref-mysqlclient-mysqlhelpermembers::  `MySqlHelper' Members

Helper class that makes it easier to work with the provider.

For a list of all members of this type, see *Note MySqlHelper Members:
connector-net-ref-mysqlclient-mysqlhelpermembers .

*Syntax: Visual Basic*

     NotInheritable Public Class MySqlHelper

*Syntax: C#*

     public sealed class MySqlHelper

*Thread Safety*

Public static (Shared in Visual Basic) members of this type are safe
for multithreaded operations. Instance members are not guaranteed to be
thread-safe.

*Requirements*

Namespace: *Note MySql.Data.MySqlClient: connector-net-ref-mysqlclient.

Assembly: MySql.Data (in MySql.Data.dll)

*See Also*

*Note MySqlHelper Members:
connector-net-ref-mysqlclient-mysqlhelpermembers, *Note
MySql.Data.MySqlClient Namespace: connector-net-ref-mysqlclient.


File: manual.info,  Node: connector-net-ref-mysqlclient-mysqlhelpermembers,  Prev: connector-net-ref-mysqlclient-mysqlhelper,  Up: connector-net-ref-mysqlclient-mysqlhelper

20.2.7.200 `MySqlHelper' Members
................................

* Menu:

* connector-net-ref-mysqlclient-mysqlhelper-executedatarow::  `MySqlHelper.ExecuteDataRow' Method
* connector-net-ref-mysqlclient-mysqlhelper-executedataset-overloads::  ExecuteDataset Method
* connector-net-ref-mysqlclient-mysqlhelper-executenonquery-overloads::  ExecuteNonQuery Method
* connector-net-ref-mysqlclient-mysqlhelper-executereader-overloads::  ExecuteReader Method
* connector-net-ref-mysqlclient-mysqlhelper-executescalar-overloads::  ExecuteScalar Method
* connector-net-ref-mysqlclient-mysqlhelper-updatedataset::  `MySqlHelper.UpdateDataSet' Method

*Note MySqlHelper overview: connector-net-ref-mysqlclient-mysqlhelper.

*Public Static (Shared) Methods*

*Note ExecuteDataRow:                Executes a single SQL statement and
connector-net-ref-mysqlclient-mysqlhelper-executedatarow.returns the first row of the
                                     resultset. A new MySqlConnection
                                     object is created, opened, and
                                     closed during this method.
*Note ExecuteDataset:                Overloaded. Executes a single SQL
connector-net-ref-mysqlclient-mysqlhelper-executedataset-overloads.statement and returns the resultset
                                     in a DataSet. A new MySqlConnection
                                     object is created, opened, and
                                     closed during this method.
*Note ExecuteNonQuery:               Overloaded. Executes a single
connector-net-ref-mysqlclient-mysqlhelper-executenonquery-overloads.command against a MySQL database.
                                     The *Note MySqlConnection:
                                     connector-net-ref-mysqlclient-mysqlconnection.
                                     is assumed to be open when the
                                     method is called and remains open
                                     after the method completes.
*Note ExecuteReader:                 Overloaded. Executes a single
connector-net-ref-mysqlclient-mysqlhelper-executereader-overloads.command against a MySQL database.
*Note ExecuteScalar:                 Overloaded. Execute a single
connector-net-ref-mysqlclient-mysqlhelper-executescalar-overloads.command against a MySQL database.
*Note UpdateDataSet:                 Updates the given table with data
connector-net-ref-mysqlclient-mysqlhelper-updatedataset.from the given DataSet

*Public Instance Methods*

Equals(inherited from Object)        Determines whether the specified
                                     Objectis equal to the current
                                     Object.
GetHashCode(inherited from Object)   Serves as a hash function for a
                                     particular type. GetHashCodeis
                                     suitable for use in hashing
                                     algorithms and data structures like
                                     a hash table.
GetType(inherited from Object)       Gets the Typeof the current
                                     instance.
ToString(inherited from Object)      Returns a Stringthat represents the
                                     current Object.

*See Also*

*Note MySqlHelper Class: connector-net-ref-mysqlclient-mysqlhelper,
*Note MySql.Data.MySqlClient Namespace: connector-net-ref-mysqlclient.


File: manual.info,  Node: connector-net-ref-mysqlclient-mysqlhelper-executedatarow,  Next: connector-net-ref-mysqlclient-mysqlhelper-executedataset-overloads,  Prev: connector-net-ref-mysqlclient-mysqlhelpermembers,  Up: connector-net-ref-mysqlclient-mysqlhelpermembers

20.2.7.201 `MySqlHelper.ExecuteDataRow' Method
..............................................

Executes a single SQL statement and returns the first row of the
resultset. A new MySqlConnection object is created, opened, and closed
during this method.

*Syntax: Visual Basic*

     Public Shared Function ExecuteDataRow( _
        ByVal connectionString As String, _
        ByVal commandText As String, _
        ParamArray parms As MySqlParameter() _
     ) As DataRow

*Syntax: C#*

     public static DataRow ExecuteDataRow(
     stringconnectionString,
     stringcommandText,
        params MySqlParameter[]parms
     );

*Parameters*

   * `connectionString': Settings to be used for the connection

   * `commandText': Command to execute

   * `parms': Parameters to use for the command

*Return Value*

DataRow containing the first row of the resultset

*See Also*

*Note MySqlHelper Class: connector-net-ref-mysqlclient-mysqlhelper,
*Note MySql.Data.MySqlClient Namespace: connector-net-ref-mysqlclient.


File: manual.info,  Node: connector-net-ref-mysqlclient-mysqlhelper-executedataset-overloads,  Next: connector-net-ref-mysqlclient-mysqlhelper-executenonquery-overloads,  Prev: connector-net-ref-mysqlclient-mysqlhelper-executedatarow,  Up: connector-net-ref-mysqlclient-mysqlhelpermembers

20.2.7.202 ExecuteDataset Method
................................

* Menu:

* connector-net-ref-mysqlclient-mysqlhelper-executedataset-overload-3::  `MySqlHelper.ExecuteDataset' Method
* connector-net-ref-mysqlclient-mysqlhelper-executedataset-overload-4::  `MySqlHelper.ExecuteDataset' Method
* connector-net-ref-mysqlclient-mysqlhelper-executedataset-overload-1::  `MySqlHelper.ExecuteDataset' Method
* connector-net-ref-mysqlclient-mysqlhelper-executedataset-overload-2::  `MySqlHelper.ExecuteDataset' Method

Executes a single SQL statement and returns the resultset in a DataSet.
The state of the *Note MySqlConnection:
connector-net-ref-mysqlclient-mysqlconnection.  object remains
unchanged after execution of this method.

*Overload List*

Executes a single SQL statement and returns the resultset in a DataSet.
The state of the *Note MySqlConnection:
connector-net-ref-mysqlclient-mysqlconnection.  object remains
unchanged after execution of this method.

   * *Note public static DataSet ExecuteDataset(MySqlConnection:
     (string);)connector-net-ref-mysqlclient-mysqlhelper-executedataset-overload-3.

Executes a single SQL statement and returns the resultset in a DataSet.
The state of the *Note MySqlConnection:
connector-net-ref-mysqlclient-mysqlconnection.  object remains
unchanged after execution of this method.

   * *Note public static DataSet ExecuteDataset(MySqlConnection:
     (string)connector-net-ref-mysqlclient-mysqlhelper-executedataset-overload-4.

Executes a single SQL statement and returns the resultset in a DataSet.
A new MySqlConnection object is created, opened, and closed during this
method.

   * *Note public static DataSet ExecuteDataset(string:
     (string);)connector-net-ref-mysqlclient-mysqlhelper-executedataset-overload-1.

Executes a single SQL statement and returns the resultset in a DataSet.
A new MySqlConnection object is created, opened, and closed during this
method.

   * *Note public static DataSet ExecuteDataset(string:
     (string)connector-net-ref-mysqlclient-mysqlhelper-executedataset-overload-2.

*See Also*

*Note MySqlHelper Class: connector-net-ref-mysqlclient-mysqlhelper,
*Note MySql.Data.MySqlClient Namespace: connector-net-ref-mysqlclient.


File: manual.info,  Node: connector-net-ref-mysqlclient-mysqlhelper-executedataset-overload-3,  Next: connector-net-ref-mysqlclient-mysqlhelper-executedataset-overload-4,  Prev: connector-net-ref-mysqlclient-mysqlhelper-executedataset-overloads,  Up: connector-net-ref-mysqlclient-mysqlhelper-executedataset-overloads

20.2.7.203 `MySqlHelper.ExecuteDataset' Method
..............................................

Executes a single SQL statement and returns the resultset in a DataSet.
The state of the *Note MySqlConnection:
connector-net-ref-mysqlclient-mysqlconnection.  object remains
unchanged after execution of this method.

*Syntax: Visual Basic*

     Overloads Public Shared Function ExecuteDataset( _
        ByVal connection As MySqlConnection, _
        ByVal commandText As String _
     ) As DataSet

*Syntax: C#*

     public static DataSet ExecuteDataset(
     MySqlConnectionconnection,
     stringcommandText
     );

*Parameters*

   * `connection': *Note MySqlConnection:
     connector-net-ref-mysqlclient-mysqlconnection.  object to use

   * `commandText': Command to execute

*Return Value*

DataSetcontaining the resultset

*See Also*

*Note MySqlHelper Class: connector-net-ref-mysqlclient-mysqlhelper,
*Note MySql.Data.MySqlClient Namespace: connector-net-ref-mysqlclient,
*Note MySqlHelper.ExecuteDataset Overload List:
connector-net-ref-mysqlclient-mysqlhelper-executedataset-overloads.


File: manual.info,  Node: connector-net-ref-mysqlclient-mysqlhelper-executedataset-overload-4,  Next: connector-net-ref-mysqlclient-mysqlhelper-executedataset-overload-1,  Prev: connector-net-ref-mysqlclient-mysqlhelper-executedataset-overload-3,  Up: connector-net-ref-mysqlclient-mysqlhelper-executedataset-overloads

20.2.7.204 `MySqlHelper.ExecuteDataset' Method
..............................................

Executes a single SQL statement and returns the resultset in a DataSet.
The state of the *Note MySqlConnection:
connector-net-ref-mysqlclient-mysqlconnection.  object remains
unchanged after execution of this method.

*Syntax: Visual Basic*

     Overloads Public Shared Function ExecuteDataset( _
        ByVal connection As MySqlConnection, _
        ByVal commandText As String, _
        ParamArray commandParameters As MySqlParameter() _
     ) As DataSet

*Syntax: C#*

     public static DataSet ExecuteDataset(
     MySqlConnectionconnection,
     stringcommandText,
        params MySqlParameter[]commandParameters
     );

*Parameters*

   * `connection': *Note MySqlConnection:
     connector-net-ref-mysqlclient-mysqlconnection.  object to use

   * `commandText': Command to execute

   * `commandParameters': Parameters to use for the command

*Return Value*

DataSetcontaining the resultset

*See Also*

*Note MySqlHelper Class: connector-net-ref-mysqlclient-mysqlhelper,
*Note MySql.Data.MySqlClient Namespace: connector-net-ref-mysqlclient,
*Note MySqlHelper.ExecuteDataset Overload List:
connector-net-ref-mysqlclient-mysqlhelper-executedataset-overloads.


File: manual.info,  Node: connector-net-ref-mysqlclient-mysqlhelper-executedataset-overload-1,  Next: connector-net-ref-mysqlclient-mysqlhelper-executedataset-overload-2,  Prev: connector-net-ref-mysqlclient-mysqlhelper-executedataset-overload-4,  Up: connector-net-ref-mysqlclient-mysqlhelper-executedataset-overloads

20.2.7.205 `MySqlHelper.ExecuteDataset' Method
..............................................

Executes a single SQL statement and returns the resultset in a DataSet.
A new MySqlConnection object is created, opened, and closed during this
method.

*Syntax: Visual Basic*

     Overloads Public Shared Function ExecuteDataset( _
        ByVal connectionString As String, _
        ByVal commandText As String _
     ) As DataSet

*Syntax: C#*

     public static DataSet ExecuteDataset(
     stringconnectionString,
     stringcommandText
     );

*Parameters*

   * `connectionString': Settings to be used for the connection

   * `commandText': Command to execute

*Return Value*

DataSetcontaining the resultset

*See Also*

*Note MySqlHelper Class: connector-net-ref-mysqlclient-mysqlhelper,
*Note MySql.Data.MySqlClient Namespace: connector-net-ref-mysqlclient,
*Note MySqlHelper.ExecuteDataset Overload List:
connector-net-ref-mysqlclient-mysqlhelper-executedataset-overloads.


File: manual.info,  Node: connector-net-ref-mysqlclient-mysqlhelper-executedataset-overload-2,  Prev: connector-net-ref-mysqlclient-mysqlhelper-executedataset-overload-1,  Up: connector-net-ref-mysqlclient-mysqlhelper-executedataset-overloads

20.2.7.206 `MySqlHelper.ExecuteDataset' Method
..............................................

Executes a single SQL statement and returns the resultset in a DataSet.
A new MySqlConnection object is created, opened, and closed during this
method.

*Syntax: Visual Basic*

     Overloads Public Shared Function ExecuteDataset( _
        ByVal connectionString As String, _
        ByVal commandText As String, _
        ParamArray commandParameters As MySqlParameter() _
     ) As DataSet

*Syntax: C#*

     public static DataSet ExecuteDataset(
     stringconnectionString,
     stringcommandText,
        params MySqlParameter[]commandParameters
     );

*Parameters*

   * `connectionString': Settings to be used for the connection

   * `commandText': Command to execute

   * `commandParameters': Parameters to use for the command

*Return Value*

DataSetcontaining the resultset

*See Also*

*Note MySqlHelper Class: connector-net-ref-mysqlclient-mysqlhelper,
*Note MySql.Data.MySqlClient Namespace: connector-net-ref-mysqlclient,
*Note MySqlHelper.ExecuteDataset Overload List:
connector-net-ref-mysqlclient-mysqlhelper-executedataset-overloads.


File: manual.info,  Node: connector-net-ref-mysqlclient-mysqlhelper-executenonquery-overloads,  Next: connector-net-ref-mysqlclient-mysqlhelper-executereader-overloads,  Prev: connector-net-ref-mysqlclient-mysqlhelper-executedataset-overloads,  Up: connector-net-ref-mysqlclient-mysqlhelpermembers

20.2.7.207 ExecuteNonQuery Method
.................................

* Menu:

* connector-net-ref-mysqlclient-mysqlhelper-executenonquery-overload-1::  `MySqlHelper.ExecuteNonQuery' Method
* connector-net-ref-mysqlclient-mysqlhelper-executenonquery-overload-2::  `MySqlHelper.ExecuteNonQuery' Method

Executes a single command against a MySQL database. The *Note
MySqlConnection: connector-net-ref-mysqlclient-mysqlconnection.  is
assumed to be open when the method is called and remains open after the
method completes.

*Overload List*

Executes a single command against a MySQL database. The *Note
MySqlConnection: connector-net-ref-mysqlclient-mysqlconnection.  is
assumed to be open when the method is called and remains open after the
method completes.

   * *Note public static int ExecuteNonQuery(MySqlConnection:
     (string)connector-net-ref-mysqlclient-mysqlhelper-executenonquery-overload-1.

Executes a single command against a MySQL database. A new *Note
MySqlConnection: connector-net-ref-mysqlclient-mysqlconnection.  is
created using the *Note ConnectionString:
connector-net-ref-mysqlclient-mysqlconnection-connectionstring.  given.

   * *Note public static int ExecuteNonQuery(string:
     (string)connector-net-ref-mysqlclient-mysqlhelper-executenonquery-overload-2.

*See Also*

*Note MySqlHelper Class: connector-net-ref-mysqlclient-mysqlhelper,
*Note MySql.Data.MySqlClient Namespace: connector-net-ref-mysqlclient.


File: manual.info,  Node: connector-net-ref-mysqlclient-mysqlhelper-executenonquery-overload-1,  Next: connector-net-ref-mysqlclient-mysqlhelper-executenonquery-overload-2,  Prev: connector-net-ref-mysqlclient-mysqlhelper-executenonquery-overloads,  Up: connector-net-ref-mysqlclient-mysqlhelper-executenonquery-overloads

20.2.7.208 `MySqlHelper.ExecuteNonQuery' Method
...............................................

Executes a single command against a MySQL database. The *Note
MySqlConnection: connector-net-ref-mysqlclient-mysqlconnection.  is
assumed to be open when the method is called and remains open after the
method completes.

*Syntax: Visual Basic*

     Overloads Public Shared Function ExecuteNonQuery( _
        ByVal connection As MySqlConnection, _
        ByVal commandText As String, _
        ParamArray commandParameters As MySqlParameter() _
     ) As Integer

*Syntax: C#*

     public static int ExecuteNonQuery(
     MySqlConnectionconnection,
     stringcommandText,
        params MySqlParameter[]commandParameters
     );

*Parameters*

   * `connection': *Note MySqlConnection:
     connector-net-ref-mysqlclient-mysqlconnection.  object to use

   * `commandText': SQL statement to be executed

   * `commandParameters': Array of *Note MySqlParameter:
     connector-net-ref-mysqlclient-mysqlparameter.  objects to use with
     the command.

*Return Value*

*See Also*

*Note MySqlHelper Class: connector-net-ref-mysqlclient-mysqlhelper,
*Note MySql.Data.MySqlClient Namespace: connector-net-ref-mysqlclient,
*Note MySqlHelper.ExecuteNonQuery Overload List:
connector-net-ref-mysqlclient-mysqlhelper-executenonquery-overloads.


File: manual.info,  Node: connector-net-ref-mysqlclient-mysqlhelper-executenonquery-overload-2,  Prev: connector-net-ref-mysqlclient-mysqlhelper-executenonquery-overload-1,  Up: connector-net-ref-mysqlclient-mysqlhelper-executenonquery-overloads

20.2.7.209 `MySqlHelper.ExecuteNonQuery' Method
...............................................

Executes a single command against a MySQL database. A new *Note
MySqlConnection: connector-net-ref-mysqlclient-mysqlconnection.  is
created using the *Note ConnectionString:
connector-net-ref-mysqlclient-mysqlconnection-connectionstring.  given.

*Syntax: Visual Basic*

     Overloads Public Shared Function ExecuteNonQuery( _
        ByVal connectionString As String, _
        ByVal commandText As String, _
        ParamArray parms As MySqlParameter() _
     ) As Integer

*Syntax: C#*

     public static int ExecuteNonQuery(
     stringconnectionString,
     stringcommandText,
        params MySqlParameter[]parms
     );

*Parameters*

   * `connectionString': *Note ConnectionString:
     connector-net-ref-mysqlclient-mysqlconnection-connectionstring.
     to use

   * `commandText': SQL statement to be executed

   * `parms': Array of *Note MySqlParameter:
     connector-net-ref-mysqlclient-mysqlparameter.  objects to use with
     the command.

*Return Value*

*See Also*

*Note MySqlHelper Class: connector-net-ref-mysqlclient-mysqlhelper,
*Note MySql.Data.MySqlClient Namespace: connector-net-ref-mysqlclient,
*Note MySqlHelper.ExecuteNonQuery Overload List:
connector-net-ref-mysqlclient-mysqlhelper-executenonquery-overloads.


File: manual.info,  Node: connector-net-ref-mysqlclient-mysqlhelper-executereader-overloads,  Next: connector-net-ref-mysqlclient-mysqlhelper-executescalar-overloads,  Prev: connector-net-ref-mysqlclient-mysqlhelper-executenonquery-overloads,  Up: connector-net-ref-mysqlclient-mysqlhelpermembers

20.2.7.210 ExecuteReader Method
...............................

* Menu:

* connector-net-ref-mysqlclient-mysqlhelper-executereader-overload-1::  `MySqlHelper.ExecuteReader' Method
* connector-net-ref-mysqlclient-mysqlhelper-executereader-overload-2::  `MySqlHelper.ExecuteReader' Method

Executes a single command against a MySQL database.

*Overload List*

Executes a single command against a MySQL database.

   * *Note public static MySqlDataReader ExecuteReader(string:
     (string);)connector-net-ref-mysqlclient-mysqlhelper-executereader-overload-1.

Executes a single command against a MySQL database.

   * *Note public static MySqlDataReader ExecuteReader(string:
     (string)connector-net-ref-mysqlclient-mysqlhelper-executereader-overload-2.

*See Also*

*Note MySqlHelper Class: connector-net-ref-mysqlclient-mysqlhelper,
*Note MySql.Data.MySqlClient Namespace: connector-net-ref-mysqlclient.


File: manual.info,  Node: connector-net-ref-mysqlclient-mysqlhelper-executereader-overload-1,  Next: connector-net-ref-mysqlclient-mysqlhelper-executereader-overload-2,  Prev: connector-net-ref-mysqlclient-mysqlhelper-executereader-overloads,  Up: connector-net-ref-mysqlclient-mysqlhelper-executereader-overloads

20.2.7.211 `MySqlHelper.ExecuteReader' Method
.............................................

Executes a single command against a MySQL database.

*Syntax: Visual Basic*

     Overloads Public Shared Function ExecuteReader( _
        ByVal connectionString As String, _
        ByVal commandText As String _
     ) As MySqlDataReader

*Syntax: C#*

     public static MySqlDataReader ExecuteReader(
     stringconnectionString,
     stringcommandText
     );

*Parameters*

   * `connectionString': Settings to use for this command

   * `commandText': Command text to use

*Return Value*

*Note MySqlDataReader: connector-net-ref-mysqlclient-mysqldatareader.
object ready to read the results of the command

*See Also*

*Note MySqlHelper Class: connector-net-ref-mysqlclient-mysqlhelper,
*Note MySql.Data.MySqlClient Namespace: connector-net-ref-mysqlclient,
*Note MySqlHelper.ExecuteReader Overload List:
connector-net-ref-mysqlclient-mysqlhelper-executereader-overloads.


File: manual.info,  Node: connector-net-ref-mysqlclient-mysqlhelper-executereader-overload-2,  Prev: connector-net-ref-mysqlclient-mysqlhelper-executereader-overload-1,  Up: connector-net-ref-mysqlclient-mysqlhelper-executereader-overloads

20.2.7.212 `MySqlHelper.ExecuteReader' Method
.............................................

Executes a single command against a MySQL database.

*Syntax: Visual Basic*

     Overloads Public Shared Function ExecuteReader( _
        ByVal connectionString As String, _
        ByVal commandText As String, _
        ParamArray commandParameters As MySqlParameter() _
     ) As MySqlDataReader

*Syntax: C#*

     public static MySqlDataReader ExecuteReader(
     stringconnectionString,
     stringcommandText,
        params MySqlParameter[]commandParameters
     );

*Parameters*

   * `connectionString': Settings to use for this command

   * `commandText': Command text to use

   * `commandParameters': Array of *Note MySqlParameter:
     connector-net-ref-mysqlclient-mysqlparameter.  objects to use with
     the command

*Return Value*

*Note MySqlDataReader: connector-net-ref-mysqlclient-mysqldatareader.
object ready to read the results of the command

*See Also*

*Note MySqlHelper Class: connector-net-ref-mysqlclient-mysqlhelper,
*Note MySql.Data.MySqlClient Namespace: connector-net-ref-mysqlclient,
*Note MySqlHelper.ExecuteReader Overload List:
connector-net-ref-mysqlclient-mysqlhelper-executereader-overloads.


File: manual.info,  Node: connector-net-ref-mysqlclient-mysqlhelper-executescalar-overloads,  Next: connector-net-ref-mysqlclient-mysqlhelper-updatedataset,  Prev: connector-net-ref-mysqlclient-mysqlhelper-executereader-overloads,  Up: connector-net-ref-mysqlclient-mysqlhelpermembers

20.2.7.213 ExecuteScalar Method
...............................

* Menu:

* connector-net-ref-mysqlclient-mysqlhelper-executescalar-overload-3::  `MySqlHelper.ExecuteScalar' Method
* connector-net-ref-mysqlclient-mysqlhelper-executescalar-overload-4::  `MySqlHelper.ExecuteScalar' Method
* connector-net-ref-mysqlclient-mysqlhelper-executescalar-overload-1::  `MySqlHelper.ExecuteScalar' Method
* connector-net-ref-mysqlclient-mysqlhelper-executescalar-overload-2::  `MySqlHelper.ExecuteScalar' Method

Execute a single command against a MySQL database.

*Overload List*

Execute a single command against a MySQL database.

   * *Note public static object ExecuteScalar(MySqlConnection:
     (string);)connector-net-ref-mysqlclient-mysqlhelper-executescalar-overload-3.

Execute a single command against a MySQL database.

   * *Note public static object ExecuteScalar(MySqlConnection:
     (string)connector-net-ref-mysqlclient-mysqlhelper-executescalar-overload-4.

Execute a single command against a MySQL database.

   * *Note public static object ExecuteScalar(string:
     (string);)connector-net-ref-mysqlclient-mysqlhelper-executescalar-overload-1.

Execute a single command against a MySQL database.

   * *Note public static object ExecuteScalar(string:
     (string)connector-net-ref-mysqlclient-mysqlhelper-executescalar-overload-2.

*See Also*

*Note MySqlHelper Class: connector-net-ref-mysqlclient-mysqlhelper,
*Note MySql.Data.MySqlClient Namespace: connector-net-ref-mysqlclient.


File: manual.info,  Node: connector-net-ref-mysqlclient-mysqlhelper-executescalar-overload-3,  Next: connector-net-ref-mysqlclient-mysqlhelper-executescalar-overload-4,  Prev: connector-net-ref-mysqlclient-mysqlhelper-executescalar-overloads,  Up: connector-net-ref-mysqlclient-mysqlhelper-executescalar-overloads

20.2.7.214 `MySqlHelper.ExecuteScalar' Method
.............................................

Execute a single command against a MySQL database.

*Syntax: Visual Basic*

     Overloads Public Shared Function ExecuteScalar( _
        ByVal connection As MySqlConnection, _
        ByVal commandText As String _
     ) As Object

*Syntax: C#*

     public static object ExecuteScalar(
     MySqlConnectionconnection,
     stringcommandText
     );

*Parameters*

   * `connection': *Note MySqlConnection:
     connector-net-ref-mysqlclient-mysqlconnection.  object to use

   * `commandText': Command text to use for the command

*Return Value*

The first column of the first row in the result set, or a null
reference if the result set is empty.

*See Also*

*Note MySqlHelper Class: connector-net-ref-mysqlclient-mysqlhelper,
*Note MySql.Data.MySqlClient Namespace: connector-net-ref-mysqlclient,
*Note MySqlHelper.ExecuteScalar Overload List:
connector-net-ref-mysqlclient-mysqlhelper-executescalar-overloads.


File: manual.info,  Node: connector-net-ref-mysqlclient-mysqlhelper-executescalar-overload-4,  Next: connector-net-ref-mysqlclient-mysqlhelper-executescalar-overload-1,  Prev: connector-net-ref-mysqlclient-mysqlhelper-executescalar-overload-3,  Up: connector-net-ref-mysqlclient-mysqlhelper-executescalar-overloads

20.2.7.215 `MySqlHelper.ExecuteScalar' Method
.............................................

Execute a single command against a MySQL database.

*Syntax: Visual Basic*

     Overloads Public Shared Function ExecuteScalar( _
        ByVal connection As MySqlConnection, _
        ByVal commandText As String, _
        ParamArray commandParameters As MySqlParameter() _
     ) As Object

*Syntax: C#*

     public static object ExecuteScalar(
     MySqlConnectionconnection,
     stringcommandText,
        params MySqlParameter[]commandParameters
     );

*Parameters*

   * `connection': *Note MySqlConnection:
     connector-net-ref-mysqlclient-mysqlconnection.  object to use

   * `commandText': Command text to use for the command

   * `commandParameters': Parameters to use for the command

*Return Value*

The first column of the first row in the result set, or a null
reference if the result set is empty.

*See Also*

*Note MySqlHelper Class: connector-net-ref-mysqlclient-mysqlhelper,
*Note MySql.Data.MySqlClient Namespace: connector-net-ref-mysqlclient,
*Note MySqlHelper.ExecuteScalar Overload List:
connector-net-ref-mysqlclient-mysqlhelper-executescalar-overloads.


File: manual.info,  Node: connector-net-ref-mysqlclient-mysqlhelper-executescalar-overload-1,  Next: connector-net-ref-mysqlclient-mysqlhelper-executescalar-overload-2,  Prev: connector-net-ref-mysqlclient-mysqlhelper-executescalar-overload-4,  Up: connector-net-ref-mysqlclient-mysqlhelper-executescalar-overloads

20.2.7.216 `MySqlHelper.ExecuteScalar' Method
.............................................

Execute a single command against a MySQL database.

*Syntax: Visual Basic*

     Overloads Public Shared Function ExecuteScalar( _
        ByVal connectionString As String, _
        ByVal commandText As String _
     ) As Object

*Syntax: C#*

     public static object ExecuteScalar(
     stringconnectionString,
     stringcommandText
     );

*Parameters*

   * `connectionString': Settings to use for the update

   * `commandText': Command text to use for the update

*Return Value*

The first column of the first row in the result set, or a null
reference if the result set is empty.

*See Also*

*Note MySqlHelper Class: connector-net-ref-mysqlclient-mysqlhelper,
*Note MySql.Data.MySqlClient Namespace: connector-net-ref-mysqlclient,
*Note MySqlHelper.ExecuteScalar Overload List:
connector-net-ref-mysqlclient-mysqlhelper-executescalar-overloads.


File: manual.info,  Node: connector-net-ref-mysqlclient-mysqlhelper-executescalar-overload-2,  Prev: connector-net-ref-mysqlclient-mysqlhelper-executescalar-overload-1,  Up: connector-net-ref-mysqlclient-mysqlhelper-executescalar-overloads

20.2.7.217 `MySqlHelper.ExecuteScalar' Method
.............................................

Execute a single command against a MySQL database.

*Syntax: Visual Basic*

     Overloads Public Shared Function ExecuteScalar( _
        ByVal connectionString As String, _
        ByVal commandText As String, _
        ParamArray commandParameters As MySqlParameter() _
     ) As Object

*Syntax: C#*

     public static object ExecuteScalar(
     stringconnectionString,
     stringcommandText,
        params MySqlParameter[]commandParameters
     );

*Parameters*

   * `connectionString': Settings to use for the command

   * `commandText': Command text to use for the command

   * `commandParameters': Parameters to use for the command

*Return Value*

The first column of the first row in the result set, or a null
reference if the result set is empty.

*See Also*

*Note MySqlHelper Class: connector-net-ref-mysqlclient-mysqlhelper,
*Note MySql.Data.MySqlClient Namespace: connector-net-ref-mysqlclient,
*Note MySqlHelper.ExecuteScalar Overload List:
connector-net-ref-mysqlclient-mysqlhelper-executescalar-overloads.


File: manual.info,  Node: connector-net-ref-mysqlclient-mysqlhelper-updatedataset,  Prev: connector-net-ref-mysqlclient-mysqlhelper-executescalar-overloads,  Up: connector-net-ref-mysqlclient-mysqlhelpermembers

20.2.7.218 `MySqlHelper.UpdateDataSet' Method
.............................................

Updates the given table with data from the given DataSet

*Syntax: Visual Basic*

     Public Shared Sub UpdateDataSet( _
        ByVal connectionString As String, _
        ByVal commandText As String, _
        ByVal ds As DataSet, _
        ByVal tablename As String _
     )

*Syntax: C#*

     public static void UpdateDataSet(
     stringconnectionString,
     stringcommandText,
     DataSetds,
     stringtablename
     );

*Parameters*

   * `connectionString': Settings to use for the update

   * `commandText': Command text to use for the update

   * `ds': DataSetcontaining the new data to use in the update

   * `tablename': Tablename in the data set to update

*See Also*

*Note MySqlHelper Class: connector-net-ref-mysqlclient-mysqlhelper,
*Note MySql.Data.MySqlClient Namespace: connector-net-ref-mysqlclient.


File: manual.info,  Node: connector-net-ref-mysqlclient-mysqlerrorcode,  Prev: connector-net-ref-mysqlclient-mysqlhelper,  Up: connector-net-ref-mysqlclient

20.2.7.219 `MySqlErrorCode' Enumeration
.......................................

*Syntax: Visual Basic*

     Public Enum MySqlErrorCode

*Syntax: C#*

     public enum MySqlErrorCode

*Members*

*Member Name*                        *Description*
PacketTooLarge                       
PasswordNotAllowed                   
DuplicateKeyEntry                    
HostNotPrivileged                    
PasswordNoMatch                      
AnonymousUser                        
DuplicateKey                         
KeyNotFound                          
DuplicateKeyName                     

*Requirements*

Namespace: *Note MySql.Data.MySqlClient: connector-net-ref-mysqlclient.

Assembly: MySql.Data (in MySql.Data.dll)

*See Also*

*Note MySql.Data.MySqlClient Namespace: connector-net-ref-mysqlclient.


File: manual.info,  Node: connector-net-ref-types,  Prev: connector-net-ref-mysqlclient,  Up: connector-net-ref

20.2.7.220 `MySql.Data.Types'
.............................

* Menu:

* connector-net-ref-typeshierarchy::  `MySql.Data.TypesHierarchy'
* connector-net-ref-types-mysqlconversionexception::  `MySqlConversionException' Class
* connector-net-ref-types-mysqldatetime::  `MySqlDateTime' Class

*Note Namespace hierarchy: connector-net-ref-typeshierarchy.

*Classes*

*Class*                              *Description*
*Note MySqlConversionException:      Summary description for
connector-net-ref-types-mysqlconversionexception.MySqlConversionException.
*Note MySqlDateTime:                 Summary description for
connector-net-ref-types-mysqldatetime.MySqlDateTime.
*Note MySqlValue:                    
connector-net-ref-types-mysqlvalue.  


File: manual.info,  Node: connector-net-ref-typeshierarchy,  Next: connector-net-ref-types-mysqlconversionexception,  Prev: connector-net-ref-types,  Up: connector-net-ref-types

20.2.7.221 `MySql.Data.TypesHierarchy'
......................................

*See Also*

*Note MySql.Data.Types Namespace: connector-net-ref-types.


File: manual.info,  Node: connector-net-ref-types-mysqlconversionexception,  Next: connector-net-ref-types-mysqldatetime,  Prev: connector-net-ref-typeshierarchy,  Up: connector-net-ref-types

20.2.7.222 `MySqlConversionException' Class
...........................................

* Menu:

* connector-net-ref-types-mysqlconversionexceptionmembers::  `MySqlConversionException' Members

Summary description for MySqlConversionException.

For a list of all members of this type, see *Note
MySqlConversionException Members:
connector-net-ref-types-mysqlconversionexceptionmembers .

*Syntax: Visual Basic*

     Public Class MySqlConversionException_
       Inherits ApplicationException

*Syntax: C#*

     public class MySqlConversionException : ApplicationException

*Thread Safety*

Public static (Sharedin Visual Basic) members of this type are safe for
multithreaded operations. Instance members are notguaranteed to be
thread-safe.

*Requirements*

Namespace: *Note MySql.Data.Types: connector-net-ref-types.

Assembly: MySql.Data (in MySql.Data.dll)

*See Also*

*Note MySqlConversionException Members:
connector-net-ref-types-mysqlconversionexceptionmembers, *Note
MySql.Data.Types Namespace: connector-net-ref-types.


File: manual.info,  Node: connector-net-ref-types-mysqlconversionexceptionmembers,  Prev: connector-net-ref-types-mysqlconversionexception,  Up: connector-net-ref-types-mysqlconversionexception

20.2.7.223 `MySqlConversionException' Members
.............................................

* Menu:

* connector-net-ref-types-mysqlconversionexceptionconstructor::  `MySqlConversionException' Constructor

*Note MySqlConversionException overview:
connector-net-ref-types-mysqlconversionexception.

*Public Instance Constructors*

*Note MySqlConversionException       Ctor
Constructor:                         
connector-net-ref-types-mysqlconversionexceptionconstructor.

*Public Instance Properties*

Data(inherited from Exception)       Gets a collection of key/value
                                     pairs that provide additional,
                                     user-defined information about the
                                     exception.
HelpLink(inherited from Exception)   Gets or sets a link to the help
                                     file associated with this exception.
InnerException(inherited from        Gets the Exceptioninstance that
Exception)                           caused the current exception.
Message(inherited from Exception)    Gets a message that describes the
                                     current exception.
Source(inherited from Exception)     Gets or sets the name of the
                                     application or the object that
                                     causes the error.
StackTrace(inherited from Exception) Gets a string representation of the
                                     frames on the call stack at the time
                                     the current exception was thrown.
TargetSite(inherited from Exception) Gets the method that throws the
                                     current exception.

*Public Instance Methods*

Equals(inherited from Object)        Determines whether the specified
                                     Objectis equal to the current
                                     Object.
GetBaseException(inherited from      When overridden in a derived class,
Exception)                           returns the Exceptionthat is the
                                     root cause of one or more
                                     subsequent exceptions.
GetHashCode(inherited from Object)   Serves as a hash function for a
                                     particular type. GetHashCodeis
                                     suitable for use in hashing
                                     algorithms and data structures like
                                     a hash table.
GetObjectData(inherited from         When overridden in a derived class,
Exception)                           sets the SerializationInfowith
                                     information about the exception.
GetType(inherited from Exception)    Gets the runtime type of the
                                     current instance.
ToString(inherited from Exception)   Creates and returns a string
                                     representation of the current
                                     exception.

*Protected Instance Properties*

HResult(inherited from Exception)    Gets or sets HRESULT, a coded
                                     numeric value that is assigned to a
                                     specific exception.

*Protected Instance Methods*

Finalize(inherited from Object)      Allows an Objectto attempt to free
                                     resources and perform other cleanup
                                     operations before the Objectis
                                     reclaimed by garbage collection.
MemberwiseClone(inherited from       Creates a shallow copy of the
Object)                              current Object.

*See Also*

*Note MySqlConversionException Class:
connector-net-ref-types-mysqlconversionexception, *Note
MySql.Data.Types Namespace: connector-net-ref-types.


File: manual.info,  Node: connector-net-ref-types-mysqlconversionexceptionconstructor,  Prev: connector-net-ref-types-mysqlconversionexceptionmembers,  Up: connector-net-ref-types-mysqlconversionexceptionmembers

20.2.7.224 `MySqlConversionException' Constructor
.................................................

*Syntax: Visual Basic*

     Public Sub New( _
        ByVal msg As String _
     )

*Syntax: C#*

     public MySqlConversionException(
     stringmsg
     );

*See Also*

*Note MySqlConversionException Class:
connector-net-ref-types-mysqlconversionexception, *Note
MySql.Data.Types Namespace: connector-net-ref-types.


File: manual.info,  Node: connector-net-ref-types-mysqldatetime,  Prev: connector-net-ref-types-mysqlconversionexception,  Up: connector-net-ref-types

20.2.7.225 `MySqlDateTime' Class
................................

* Menu:

* connector-net-ref-types-mysqldatetimemembers::  `MySqlDateTime' Members

Summary description for MySqlDateTime.

For a list of all members of this type, see *Note MySqlDateTime
Members: connector-net-ref-types-mysqldatetimemembers .

*Syntax: Visual Basic*

     Public Class MySqlDateTime_
       Inherits MySqlValue_
       Implements IConvertible, IComparable

*Syntax: C#*

     public class MySqlDateTime : MySqlValue, IConvertible, IComparable

*Thread Safety*

Public static (Shared in Visual Basic) members of this type are safe
for multithreaded operations. Instance members are not guaranteed to be
thread-safe.

*Requirements*

Namespace: *Note MySql.Data.Types: connector-net-ref-types.

Assembly: MySql.Data (in MySql.Data.dll)

*See Also*

*Note MySqlDateTime Members:
connector-net-ref-types-mysqldatetimemembers, *Note MySql.Data.Types
Namespace: connector-net-ref-types.


File: manual.info,  Node: connector-net-ref-types-mysqldatetimemembers,  Prev: connector-net-ref-types-mysqldatetime,  Up: connector-net-ref-types-mysqldatetime

20.2.7.226 `MySqlDateTime' Members
..................................

* Menu:

* connector-net-ref-types-mysqldatetime-op-explicit::  `MySqlDateTime' Explicit `MySqlDateTime' to `DateTime' Conversion
* connector-net-ref-types-mysqldatetime-day::  Day Property
* connector-net-ref-types-mysqldatetime-hour::  Hour Property
* connector-net-ref-types-mysqlvalue-isnull::  IsNull Property
* connector-net-ref-types-mysqldatetime-isvaliddatetime::  IsValidDateTime Property
* connector-net-ref-types-mysqldatetime-minute::  Minute Property
* connector-net-ref-types-mysqldatetime-month::  Month Property
* connector-net-ref-types-mysqldatetime-second::  Second Property
* connector-net-ref-types-mysqldatetime-year::  Year Property
* connector-net-ref-types-mysqldatetime-getdatetime::  `MySqlDateTime.GetDateTime' Method
* connector-net-ref-types-mysqldatetime-tostring::  `MySqlDateTime.ToString' Method

*Note MySqlDateTime overview: connector-net-ref-types-mysqldatetime.

*Public Static (Shared) Type Conversions*

*Note Explicit MySqlDateTime to      
DateTime Conversion:                 
connector-net-ref-types-mysqldatetime-op-explicit.

*Public Instance Properties*

*Note Day:                           Returns the day portion of this
connector-net-ref-types-mysqldatetime-day.datetime
*Note Hour:                          Returns the hour portion of this
connector-net-ref-types-mysqldatetime-hour.datetime
*Note IsNull:                        
connector-net-ref-types-mysqlvalue-isnull.
(inherited from MySqlValue)          
*Note IsValidDateTime:               Indicates if this object contains a
connector-net-ref-types-mysqldatetime-isvaliddatetime.value that can be represented as a
                                     DateTime
*Note Minute:                        Returns the minute portion of this
connector-net-ref-types-mysqldatetime-minute.datetime
*Note Month:                         Returns the month portion of this
connector-net-ref-types-mysqldatetime-month.datetime
*Note Second:                        Returns the second portion of this
connector-net-ref-types-mysqldatetime-second.datetime
*Note ValueAsObject:                 Returns the value of this field as
connector-net-ref-types-mysqlvalue-valueasobject.an object
(inherited from MySqlValue)          
*Note Year:                          Returns the year portion of this
connector-net-ref-types-mysqldatetime-year.datetime

*Public Instance Methods*

Equals(inherited from Object)        Determines whether the specified
                                     Objectis equal to the current
                                     Object.
*Note GetDateTime:                   Returns this value as a DateTime
connector-net-ref-types-mysqldatetime-getdatetime.
GetHashCode(inherited from Object)   Serves as a hash function for a
                                     particular type. GetHashCodeis
                                     suitable for use in hashing
                                     algorithms and data structures like
                                     a hash table.
GetType(inherited from Object)       Gets the Typeof the current
                                     instance.
*Note ToString:                      Returns a MySQL specific string
connector-net-ref-types-mysqldatetime-tostring.representation of this value

*Protected Instance Fields*

*Note classType:                     The system type represented by this
connector-net-ref-types-mysqlvalue-classtype.value
(inherited from MySqlValue)          
*Note dbType:                        The generic dbtype of this value
connector-net-ref-types-mysqlvalue-dbtype.
(inherited from MySqlValue)          
*Note isNull:                        Is this value null
connector-net-ref-types-mysqlvalue-isnull.
(inherited from MySqlValue)          
*Note mySqlDbType:                   The specific MySQL db type
connector-net-ref-types-mysqlvalue-mysqldbtype.
(inherited from MySqlValue)          
*Note mySqlTypeName:                 The MySQL specific typename of this
connector-net-ref-types-mysqlvalue-mysqltypename.value
(inherited from MySqlValue)          
*Note objectValue:                   
connector-net-ref-types-mysqlvalue-objectvalue.
(inherited from MySqlValue)          

*Protected Instance Methods*

Finalize(inherited from Object)      Allows an Objectto attempt to free
                                     resources and perform other cleanup
                                     operations before the Objectis
                                     reclaimed by garbage collection.
MemberwiseClone(inherited from       Creates a shallow copy of the
Object)                              current Object.

*See Also*

*Note MySqlDateTime Class: connector-net-ref-types-mysqldatetime, *Note
MySql.Data.Types Namespace: connector-net-ref-types.


File: manual.info,  Node: connector-net-ref-types-mysqldatetime-op-explicit,  Next: connector-net-ref-types-mysqldatetime-day,  Prev: connector-net-ref-types-mysqldatetimemembers,  Up: connector-net-ref-types-mysqldatetimemembers

20.2.7.227 `MySqlDateTime' Explicit `MySqlDateTime' to `DateTime' Conversion
............................................................................

*Syntax: Visual Basic*

     MySqlDateTime.op_Explicit(val)

*Syntax: C#*

     public static explicit operator DateTime(
     MySqlDateTimeval
     );

*Parameters*

   * `val':

*Return Value*

*See Also*

*Note MySqlDateTime Class: connector-net-ref-types-mysqldatetime, *Note
MySql.Data.Types Namespace: connector-net-ref-types.


File: manual.info,  Node: connector-net-ref-types-mysqldatetime-day,  Next: connector-net-ref-types-mysqldatetime-hour,  Prev: connector-net-ref-types-mysqldatetime-op-explicit,  Up: connector-net-ref-types-mysqldatetimemembers

20.2.7.228 Day Property
.......................

Returns the day portion of this datetime

*Syntax: Visual Basic*

     Public Property Day As Integer

*Syntax: C#*

     public int Day {get; set;}

*See Also*

*Note MySqlDateTime Class: connector-net-ref-types-mysqldatetime, *Note
MySql.Data.Types Namespace: connector-net-ref-types.


File: manual.info,  Node: connector-net-ref-types-mysqldatetime-hour,  Next: connector-net-ref-types-mysqlvalue-isnull,  Prev: connector-net-ref-types-mysqldatetime-day,  Up: connector-net-ref-types-mysqldatetimemembers

20.2.7.229 Hour Property
........................

Returns the hour portion of this datetime

*Syntax: Visual Basic*

     Public Property Hour As Integer

*Syntax: C#*

     public int Hour {get; set;}

*See Also*

*Note MySqlDateTime Class: connector-net-ref-types-mysqldatetime, *Note
MySql.Data.Types Namespace: connector-net-ref-types.


File: manual.info,  Node: connector-net-ref-types-mysqlvalue-isnull,  Next: connector-net-ref-types-mysqldatetime-isvaliddatetime,  Prev: connector-net-ref-types-mysqldatetime-hour,  Up: connector-net-ref-types-mysqldatetimemembers

20.2.7.230 IsNull Property
..........................

* Menu:

* connector-net-ref-types-mysqlvalue::  `MySqlValue' Class

*Syntax: Visual Basic*

     Public Property IsNull As Boolean

*Syntax: C#*

     public bool IsNull {get; set;}

*See Also*

*Note MySqlValue Class: connector-net-ref-types-mysqlvalue, *Note
MySql.Data.Types Namespace: connector-net-ref-types.


File: manual.info,  Node: connector-net-ref-types-mysqlvalue,  Prev: connector-net-ref-types-mysqlvalue-isnull,  Up: connector-net-ref-types-mysqlvalue-isnull

20.2.7.231 `MySqlValue' Class
.............................

* Menu:

* connector-net-ref-types-mysqlvaluemembers::  `MySqlValue' Members

For a list of all members of this type, see *Note MySqlValue Members:
connector-net-ref-types-mysqlvaluemembers .

*Syntax: Visual Basic*

     MustInherit Public Class MySqlValue

*Syntax: C#*

     public abstract class MySqlValue

*Thread Safety*

Public static (Shared in Visual Basic) members of this type are safe
for multithreaded operations. Instance members are not guaranteed to be
thread-safe.

*Requirements*

Namespace: *Note MySql.Data.Types: connector-net-ref-types.

Assembly: MySql.Data (in MySql.Data.dll)

*See Also*

*Note MySqlValue Members: connector-net-ref-types-mysqlvaluemembers,
*Note MySql.Data.Types Namespace: connector-net-ref-types.


File: manual.info,  Node: connector-net-ref-types-mysqlvaluemembers,  Prev: connector-net-ref-types-mysqlvalue,  Up: connector-net-ref-types-mysqlvalue

20.2.7.232 `MySqlValue' Members
...............................

* Menu:

* connector-net-ref-types-mysqlvalue-numberformat::  `MySqlValue.numberFormat' Field
* connector-net-ref-types-mysqlvalueconstructor::  `MySqlValue' Constructor
* connector-net-ref-types-mysqlvalue-valueasobject::  ValueAsObject Property
* connector-net-ref-types-mysqlvalue-tostring::  `MySqlValue.ToString' Method
* connector-net-ref-types-mysqlvalue-classtype::  `MySqlValue.classType' Field
* connector-net-ref-types-mysqlvalue-dbtype::  `MySqlValue.dbType' Field
* connector-net-ref-types-mysqlvalue-mysqldbtype::  `MySqlValue.mySqlDbType' Field
* connector-net-ref-types-mysqlvalue-mysqltypename::  `MySqlValue.mySqlTypeName' Field
* connector-net-ref-types-mysqlvalue-objectvalue::  `MySqlValue.objectValue' Field

*Note MySqlValue overview: connector-net-ref-types-mysqlvalue.

*Protected Static (Shared) Fields*

*Note numberFormat:                  
connector-net-ref-types-mysqlvalue-numberformat.

*Public Instance Constructors*

*Note MySqlValue Constructor:        Initializes a new instance of the
connector-net-ref-types-mysqlvalueconstructor.*Note MySqlValue:
                                     connector-net-ref-types-mysqlvalue.
                                     class.

*Public Instance Properties*

*Note IsNull:                        
connector-net-ref-types-mysqlvalue-isnull.
*Note ValueAsObject:                 Returns the value of this field as
connector-net-ref-types-mysqlvalue-valueasobject.an object

*Public Instance Methods*

Equals(inherited from Object)        Determines whether the specified
                                     Objectis equal to the current
                                     Object.
GetHashCode(inherited from Object)   Serves as a hash function for a
                                     particular type. GetHashCodeis
                                     suitable for use in hashing
                                     algorithms and data structures like
                                     a hash table.
GetType(inherited from Object)       Gets the Typeof the current
                                     instance.
*Note ToString:                      Returns a string representation of
connector-net-ref-types-mysqlvalue-tostring.this value

*Protected Instance Fields*

*Note classType:                     The system type represented by this
connector-net-ref-types-mysqlvalue-classtype.value
*Note dbType:                        The generic dbtype of this value
connector-net-ref-types-mysqlvalue-dbtype.
*Note isNull:                        Is this value null
connector-net-ref-types-mysqlvalue-isnull.
*Note mySqlDbType:                   The specific MySQL db type
connector-net-ref-types-mysqlvalue-mysqldbtype.
*Note mySqlTypeName:                 The MySQL specific typename of this
connector-net-ref-types-mysqlvalue-mysqltypename.value
*Note objectValue:                   
connector-net-ref-types-mysqlvalue-objectvalue.

*Protected Instance Methods*

Finalize(inherited from Object)      Allows an Objectto attempt to free
                                     resources and perform other cleanup
                                     operations before the Objectis
                                     reclaimed by garbage collection.
MemberwiseClone(inherited from       Creates a shallow copy of the
Object)                              current Object.

*See Also*

*Note MySqlValue Class: connector-net-ref-types-mysqlvalue, *Note
MySql.Data.Types Namespace: connector-net-ref-types.


File: manual.info,  Node: connector-net-ref-types-mysqlvalue-numberformat,  Next: connector-net-ref-types-mysqlvalueconstructor,  Prev: connector-net-ref-types-mysqlvaluemembers,  Up: connector-net-ref-types-mysqlvaluemembers

20.2.7.233 `MySqlValue.numberFormat' Field
..........................................

*Syntax: Visual Basic*

     Protected Shared numberFormat As NumberFormatInfo

*Syntax: C#*

     protected static NumberFormatInfo numberFormat;

*See Also*

*Note MySqlValue Class: connector-net-ref-types-mysqlvalue, *Note
MySql.Data.Types Namespace: connector-net-ref-types.


File: manual.info,  Node: connector-net-ref-types-mysqlvalueconstructor,  Next: connector-net-ref-types-mysqlvalue-valueasobject,  Prev: connector-net-ref-types-mysqlvalue-numberformat,  Up: connector-net-ref-types-mysqlvaluemembers

20.2.7.234 `MySqlValue' Constructor
...................................

Initializes a new instance of the *Note MySqlValue:
connector-net-ref-types-mysqlvalue.  class.

*Syntax: Visual Basic*

     Public Sub New()

*Syntax: C#*

     public MySqlValue();

*See Also*

*Note MySqlValue Class: connector-net-ref-types-mysqlvalue, *Note
MySql.Data.Types Namespace: connector-net-ref-types.


File: manual.info,  Node: connector-net-ref-types-mysqlvalue-valueasobject,  Next: connector-net-ref-types-mysqlvalue-tostring,  Prev: connector-net-ref-types-mysqlvalueconstructor,  Up: connector-net-ref-types-mysqlvaluemembers

20.2.7.235 ValueAsObject Property
.................................

Returns the value of this field as an object

*Syntax: Visual Basic*

     Public ReadOnly Property ValueAsObject As Object

*Syntax: C#*

     public object ValueAsObject {get;}

*See Also*

*Note MySqlValue Class: connector-net-ref-types-mysqlvalue, *Note
MySql.Data.Types Namespace: connector-net-ref-types.


File: manual.info,  Node: connector-net-ref-types-mysqlvalue-tostring,  Next: connector-net-ref-types-mysqlvalue-classtype,  Prev: connector-net-ref-types-mysqlvalue-valueasobject,  Up: connector-net-ref-types-mysqlvaluemembers

20.2.7.236 `MySqlValue.ToString' Method
.......................................

Returns a string representation of this value

*Syntax: Visual Basic*

     Overrides Public Function ToString() As String

*Syntax: C#*

     public override string ToString();

*See Also*

*Note MySqlValue Class: connector-net-ref-types-mysqlvalue, *Note
MySql.Data.Types Namespace: connector-net-ref-types.


File: manual.info,  Node: connector-net-ref-types-mysqlvalue-classtype,  Next: connector-net-ref-types-mysqlvalue-dbtype,  Prev: connector-net-ref-types-mysqlvalue-tostring,  Up: connector-net-ref-types-mysqlvaluemembers

20.2.7.237 `MySqlValue.classType' Field
.......................................

The system type represented by this value

*Syntax: Visual Basic*

     Protected classType As Type

*Syntax: C#*

     protected Type classType;

*See Also*

*Note MySqlValue Class: connector-net-ref-types-mysqlvalue, *Note
MySql.Data.Types Namespace: connector-net-ref-types.


File: manual.info,  Node: connector-net-ref-types-mysqlvalue-dbtype,  Next: connector-net-ref-types-mysqlvalue-mysqldbtype,  Prev: connector-net-ref-types-mysqlvalue-classtype,  Up: connector-net-ref-types-mysqlvaluemembers

20.2.7.238 `MySqlValue.dbType' Field
....................................

The generic dbtype of this value

*Syntax: Visual Basic*

     Protected dbType As DbType

*Syntax: C#*

     protected DbType dbType;

*See Also*

*Note MySqlValue Class: connector-net-ref-types-mysqlvalue, *Note
MySql.Data.Types Namespace: connector-net-ref-types.


File: manual.info,  Node: connector-net-ref-types-mysqlvalue-mysqldbtype,  Next: connector-net-ref-types-mysqlvalue-mysqltypename,  Prev: connector-net-ref-types-mysqlvalue-dbtype,  Up: connector-net-ref-types-mysqlvaluemembers

20.2.7.239 `MySqlValue.mySqlDbType' Field
.........................................

The specific MySQL db type

*Syntax: Visual Basic*

     Protected mySqlDbType As MySqlDbType

*Syntax: C#*

     protected MySqlDbType mySqlDbType;

*See Also*

*Note MySqlValue Class: connector-net-ref-types-mysqlvalue, *Note
MySql.Data.Types Namespace: connector-net-ref-types.


File: manual.info,  Node: connector-net-ref-types-mysqlvalue-mysqltypename,  Next: connector-net-ref-types-mysqlvalue-objectvalue,  Prev: connector-net-ref-types-mysqlvalue-mysqldbtype,  Up: connector-net-ref-types-mysqlvaluemembers

20.2.7.240 `MySqlValue.mySqlTypeName' Field
...........................................

The MySQL specific typename of this value

*Syntax: Visual Basic*

     Protected mySqlTypeName As String

*Syntax: C#*

     protected string mySqlTypeName;

*See Also*

*Note MySqlValue Class: connector-net-ref-types-mysqlvalue, *Note
MySql.Data.Types Namespace: connector-net-ref-types.


File: manual.info,  Node: connector-net-ref-types-mysqlvalue-objectvalue,  Prev: connector-net-ref-types-mysqlvalue-mysqltypename,  Up: connector-net-ref-types-mysqlvaluemembers

20.2.7.241 `MySqlValue.objectValue' Field
.........................................

*Syntax: Visual Basic*

     Protected objectValue As Object

*Syntax: C#*

     protected object objectValue;

*See Also*

*Note MySqlValue Class: connector-net-ref-types-mysqlvalue, *Note
MySql.Data.Types Namespace: connector-net-ref-types.


File: manual.info,  Node: connector-net-ref-types-mysqldatetime-isvaliddatetime,  Next: connector-net-ref-types-mysqldatetime-minute,  Prev: connector-net-ref-types-mysqlvalue-isnull,  Up: connector-net-ref-types-mysqldatetimemembers

20.2.7.242 IsValidDateTime Property
...................................

Indicates if this object contains a value that can be represented as a
DateTime

*Syntax: Visual Basic*

     Public ReadOnly Property IsValidDateTime As Boolean

*Syntax: C#*

     public bool IsValidDateTime {get;}

*See Also*

*Note MySqlDateTime Class: connector-net-ref-types-mysqldatetime, *Note
MySql.Data.Types Namespace: connector-net-ref-types.


File: manual.info,  Node: connector-net-ref-types-mysqldatetime-minute,  Next: connector-net-ref-types-mysqldatetime-month,  Prev: connector-net-ref-types-mysqldatetime-isvaliddatetime,  Up: connector-net-ref-types-mysqldatetimemembers

20.2.7.243 Minute Property
..........................

Returns the minute portion of this datetime

*Syntax: Visual Basic*

     Public Property Minute As Integer

*Syntax: C#*

     public int Minute {get; set;}

*See Also*

*Note MySqlDateTime Class: connector-net-ref-types-mysqldatetime, *Note
MySql.Data.Types Namespace: connector-net-ref-types.


File: manual.info,  Node: connector-net-ref-types-mysqldatetime-month,  Next: connector-net-ref-types-mysqldatetime-second,  Prev: connector-net-ref-types-mysqldatetime-minute,  Up: connector-net-ref-types-mysqldatetimemembers

20.2.7.244 Month Property
.........................

Returns the month portion of this datetime

*Syntax: Visual Basic*

     Public Property Month As Integer

*Syntax: C#*

     public int Month {get; set;}

*See Also*

*Note MySqlDateTime Class: connector-net-ref-types-mysqldatetime, *Note
MySql.Data.Types Namespace: connector-net-ref-types.


File: manual.info,  Node: connector-net-ref-types-mysqldatetime-second,  Next: connector-net-ref-types-mysqldatetime-year,  Prev: connector-net-ref-types-mysqldatetime-month,  Up: connector-net-ref-types-mysqldatetimemembers

20.2.7.245 Second Property
..........................

Returns the second portion of this datetime

*Syntax: Visual Basic*

     Public Property Second As Integer

*Syntax: C#*

     public int Second {get; set;}

*See Also*

*Note MySqlDateTime Class: connector-net-ref-types-mysqldatetime, *Note
MySql.Data.Types Namespace: connector-net-ref-types.


File: manual.info,  Node: connector-net-ref-types-mysqldatetime-year,  Next: connector-net-ref-types-mysqldatetime-getdatetime,  Prev: connector-net-ref-types-mysqldatetime-second,  Up: connector-net-ref-types-mysqldatetimemembers

20.2.7.246 Year Property
........................

Returns the year portion of this datetime

*Syntax: Visual Basic*

     Public Property Year As Integer

*Syntax: C#*

     public int Year {get; set;}

*See Also*

*Note MySqlDateTime Class: connector-net-ref-types-mysqldatetime, *Note
MySql.Data.Types Namespace: connector-net-ref-types.


File: manual.info,  Node: connector-net-ref-types-mysqldatetime-getdatetime,  Next: connector-net-ref-types-mysqldatetime-tostring,  Prev: connector-net-ref-types-mysqldatetime-year,  Up: connector-net-ref-types-mysqldatetimemembers

20.2.7.247 `MySqlDateTime.GetDateTime' Method
.............................................

Returns this value as a DateTime

*Syntax: Visual Basic*

     Public Function GetDateTime() As Date

*Syntax: C#*

     public DateTime GetDateTime();

*See Also*

*Note MySqlDateTime Class: connector-net-ref-types-mysqldatetime, *Note
MySql.Data.Types Namespace: connector-net-ref-types.


File: manual.info,  Node: connector-net-ref-types-mysqldatetime-tostring,  Prev: connector-net-ref-types-mysqldatetime-getdatetime,  Up: connector-net-ref-types-mysqldatetimemembers

20.2.7.248 `MySqlDateTime.ToString' Method
..........................................

Returns a MySQL specific string representation of this value

*Syntax: Visual Basic*

     Overrides Public Function ToString() As String

*Syntax: C#*

     public override string ToString();

*See Also*

*Note MySqlDateTime Class: connector-net-ref-types-mysqldatetime, *Note
MySql.Data.Types Namespace: connector-net-ref-types.


File: manual.info,  Node: connector-net-support,  Next: connector-net-faq,  Prev: connector-net-ref,  Up: connector-net

20.2.8 Connector/Net Support
----------------------------

* Menu:

* connector-net-support-community::  Connector/Net Community Support
* connector-net-support-bug-report::  How to report Connector/Net Problems or Bugs
* connector-net-support-changehistory::  Connector/Net Change History

The developers of Connector/Net greatly value the input of our users in
the software development process. If you find Connector/Net lacking
some feature important to you, or if you discover a bug and need to
file a bug report, please use the instructions in *Note bug-reports::.


File: manual.info,  Node: connector-net-support-community,  Next: connector-net-support-bug-report,  Prev: connector-net-support,  Up: connector-net-support

20.2.8.1 Connector/Net Community Support
........................................

   * Community support for Connector/Net can be found through the
     forums at `http://forums.mysql.com'.

   * Community support for Connector/Net can also be found through the
     mailing lists at `http://lists.mysql.com'.

   * Paid support is available from Oracle. Additional information is
     available at `http://dev.mysql.com/support/'.


File: manual.info,  Node: connector-net-support-bug-report,  Next: connector-net-support-changehistory,  Prev: connector-net-support-community,  Up: connector-net-support

20.2.8.2 How to report Connector/Net Problems or Bugs
.....................................................

If you encounter difficulties or problems with Connector/Net, contact
the Connector/Net community *Note connector-net-support-community::.

You should first try to execute the same SQL statements and commands
from the *Note `mysql': mysql. client program or from `admndemo'. This
helps you determine whether the error is in Connector/Net or MySQL.

If reporting a problem, you should ideally include the following
information with the email:

   * Operating system and version

   * Connector/Net version

   * MySQL server version

   * Copies of error messages or other unexpected output

   * Simple reproducible sample

Remember that the more information you can supply to us, the more
likely it is that we can fix the problem.

If you believe the problem to be a bug, then you must report the bug
through `http://bugs.mysql.com/'.


File: manual.info,  Node: connector-net-support-changehistory,  Prev: connector-net-support-bug-report,  Up: connector-net-support

20.2.8.3 Connector/Net Change History
.....................................

The Connector/Net Change History (Changelog) is located with the main
Changelog for MySQL. See *Note connector-net-news::.


File: manual.info,  Node: connector-net-faq,  Prev: connector-net-support,  Up: connector-net

20.2.9 Connector/Net FAQ
------------------------

*Questions*
   * 20.2.9.1: How do I obtain the value of an auto-incremented column?

*Questions and Answers* *20.2.9.1: ** How do I obtain the value of an
auto-incremented column?  *

When using CommandBuilder, setting `ReturnGeneratedIdentifiers'
property to `true' no longer works, as CommandBuilder does not add
`last_insert_id()' by default.

CommandBuilder hooks up to the DataAdapter.RowUpdating event handler,
which means it will get called for every row. It examines the command
object and, if it is the same referenced object, it essentially
rebuilds the object, thereby destroying your command text changes.

One approach to solving this problem is to clone the command object so
you have a different actual reference:

     dataAdapter.InsertCommand = cb.GetInsertCommand().Clone()

This will work, but since the CommandBuilder is still connected to the
DataAdapter, the RowUpdating event will still fire and performance will
be hit. To stop that, once all your commands have been added you need
to disconnect the CommandBuilder from the DataAdapter:

     cb.DataAdapter = null;

The last requirement is to make sure the `id' that is returned by
`last_insert_id()' has the correct name. For example:

     SELECT last_insert_id() AS id

A complete working example is shown here:

     using System;
     using System.Collections.Generic;
     using System.Linq;
     using System.Text;

     using System.Data;
     using MySql.Data;
     using MySql.Data.MySqlClient;

     namespace GetAutoIncId
     {
         class Program
         {
             static void Main(string[] args)
             {
                 string connStr = "server=localhost;user=root;database=TestDB;port=3306;password=******;";
                 MySqlConnection conn = new MySqlConnection(connStr);

                 try
                 {
                     Console.WriteLine("Connecting to MySQL...");
                     conn.Open();

                     string sql = "SELECT * FROM TestTable";

                     MySqlDataAdapter da = new MySqlDataAdapter(sql, conn);
                     MySqlCommandBuilder cb = new MySqlCommandBuilder(da);

                     MySqlCommand cmd = new MySqlCommand();
                     cmd.Connection = conn;
                     cmd.CommandText = sql;
                     // use Cloned object to avoid .NET rebuilding the object, and
                     // thereby throwing away our command text additions.
                     MySqlCommand insertCmd = cb.GetInsertCommand().Clone();
                     insertCmd.CommandText = insertCmd.CommandText + ";SELECT last_insert_id() AS id";
                     insertCmd.UpdatedRowSource = UpdateRowSource.FirstReturnedRecord;
                     da.InsertCommand = insertCmd;
                     cb.DataAdapter = null; // Unhook RowUpdating event handler

                     DataTable dt = new DataTable();
                     da.Fill(dt);

                     DataRow row = dt.NewRow();
                     row["name"] = "Joe Smith";

                     dt.Rows.Add(row);
                     da.Update(dt);

                     System.Console.WriteLine("ID after update: " + row["id"]);
                 }
                 catch (Exception ex)
                 {
                     Console.WriteLine(ex.ToString());
                 }

                 conn.Close();
                 Console.WriteLine("Done.");
             }
         }
     }


File: manual.info,  Node: connector-j,  Next: connector-mxj,  Prev: connector-net,  Up: connectors-apis

20.3 MySQL Connector/J
======================

* Menu:

* connector-j-versions::         Connector/J Versions
* connector-j-installing::       Connector/J Installation
* connector-j-examples::         Connector/J Examples
* connector-j-reference::        Connector/J (JDBC) Reference
* connector-j-usagenotes::       Connector/J Notes and Tips
* connector-j-support::          Connector/J Support

MySQL provides connectivity for client applications developed in the
Java programming language through a JDBC driver, which is called MySQL
Connector/J.

MySQL Connector/J is a JDBC Type 4 driver. Different versions are
available that are compatible with the JDBC 3.0 and JDBC 4.0
specifications. The Type 4 designation means that the driver is
pure-Java implementation of the MySQL protocol and does not rely on the
MySQL client libraries.

Although JDBC is useful by itself, we would hope that if you are not
familiar with JDBC that after reading the first few sections of this
manual, that you would avoid using naked JDBC for all but the most
trivial problems and consider using one of the popular persistence
frameworks such as Hibernate (http://www.hibernate.org/), Spring's JDBC
templates (http://www.springframework.org/) or Ibatis SQL Maps
(http://ibatis.apache.org/) to do the majority of repetitive work and
heavier lifting that is sometimes required with JDBC.

This section is not designed to be a complete JDBC tutorial. If you
need more information about using JDBC you might be interested in the
following online tutorials that are more in-depth than the information
presented here:

   * JDBC Basics
     (http://java.sun.com/docs/books/tutorial/jdbc/basics/index.html):
     A tutorial from Sun covering beginner topics in JDBC

   * JDBC Short Course
     (http://java.sun.com/developer/onlineTraining/Database/JDBCShortCourse/index.html):
     A more in-depth tutorial from Sun and JGuru

*Key topics:*

   * For help with connection strings, connection options setting up
     your connection through JDBC, see *Note
     connector-j-reference-configuration-properties::.

   * For tips on using Connector/J and JDBC with generic J2EE toolkits,
     see *Note connector-j-usagenotes-j2ee::.

   * Developers using the Tomcat server platform, see *Note
     connector-j-usagenotes-tomcat::.

   * Developers using JBoss, see *Note connector-j-usagenotes-jboss::.

   * Developers using Spring, see *Note
     connector-j-usagenotes-spring-config::.

   * Developers using GlassFish (Sun Application Server), see *Note
     connector-j-usagenotes-glassfish-config::.


File: manual.info,  Node: connector-j-versions,  Next: connector-j-installing,  Prev: connector-j,  Up: connector-j

20.3.1 Connector/J Versions
---------------------------

* Menu:

* connector-j-versions-java::    Java Versions Supported

There are currently four versions of MySQL Connector/J available:

   * Connector/J 5.1 is the Type 4 pure Java JDBC driver, which
     conforms to the JDBC 3.0 and JDBC 4.0 specifications. It provides
     compatibility with all the functionality of MySQL, including 4.1,
     5.0, 5.1, 5.4 and 5.5. Connector/J 5.1 provides ease of
     development features, including auto-registration with the Driver
     Manager, standardized validity checks, categorized SQLExceptions,
     support for the JDBC-4.0 XML processing, per connection client
     information, *Note `NCHAR': char, *Note `NVARCHAR': char. and
     `NCLOB' types. This release also includes all bug fixes up to and
     including Connector/J 5.0.6.

   * Connector/J 5.0 provides support for all the functionality offered
     by Connector/J 3.1 and includes distributed transaction (XA)
     support.

   * Connector/J 3.1 was designed for connectivity to MySQL 4.1 and
     MySQL 5.0 servers and provides support for all the functionality
     in MySQL 5.0 except distributed transaction (XA) support.

   * Connector/J 3.0 provides core functionality and was designed with
     connectivity to MySQL 3.x or MySQL 4.1 servers, although it will
     provide basic compatibility with later versions of MySQL.
     Connector/J 3.0 does not support server-side prepared statements,
     and does not support any of the features in versions of MySQL
     later than 4.1.

The following table summarizes the Connector/J versions available:

Connector/J    Driver Type    JDBC version   MySQL Server   Status
version                                      version        
5.1            4              3.0, 4.0       4.1, 5.0,      Recommended
                                             5.1, 5.4, 5.5  version
5.0            4              3.0            4.1, 5.0       Released
                                                            version
3.1            4              3.0            4.1, 5.0       Obsolete
3.0            4              3.0            3.x, 4.1       Obsolete

The current recommended version for Connector/J is 5.1. This guide
covers all four connector versions, with specific notes given where a
setting applies to a specific option.


File: manual.info,  Node: connector-j-versions-java,  Prev: connector-j-versions,  Up: connector-j-versions

20.3.1.1 Java Versions Supported
................................

The following table summarizes Connector/J Java dependencies:

Connector/J version    Java RTE required      JDK required (to
                                              build source code)
5.1                    1.5.x, 1.6.x           1.6.x and 1.5.x
5.0                    1.3.x, 1.4.x, 1.5.x,   1.4.2, 1.5.x, 1.6.x
                       1.6.x                  
3.1                    1.2.x, 1.3.x, 1.4.x,   1.4.2, 1.5.x, 1.6.x
                       1.5.x, 1.6.x           
3.0                    1.2.x, 1.3.x, 1.4.x,   1.4.2, 1.5.x, 1.6.x
                       1.5.x, 1.6.x           

MySQL Connector/J does not support JDK-1.1.x or JDK-1.0.x.

Because of the implementation of java.sql.Savepoint, Connector/J 3.1.0
and newer will not run on a Java runtime older than 1.4 unless the
class verifier is turned off (by setting the `-Xverify:none' option to
the Java runtime). This is because the class verifier will try to load
the class definition for java.sql.Savepoint even though it is not
accessed by the driver unless you actually use savepoint functionality.

Caching functionality provided by Connector/J 3.1.0 or newer is also
not available on JVMs older than 1.4.x, as it relies on
java.util.LinkedHashMap which was first available in JDK-1.4.0.

If you are building Connector/J from source code using the source
distribution (see *Note connector-j-installing-source::) then you must
use JDK 1.4.2 or newer to compile the Connector package. For
Connector/J 5.1 you must have both JDK-1.6.x. and JDK-1.5.x installed
to be able to build the source code.


File: manual.info,  Node: connector-j-installing,  Next: connector-j-examples,  Prev: connector-j-versions,  Up: connector-j

20.3.2 Connector/J Installation
-------------------------------

* Menu:

* connector-j-binary-installation::  Installing Connector/J from a Binary Distribution
* connector-j-installing-classpath::  Installing the Driver and Configuring the `CLASSPATH'
* connector-j-installing-upgrading::  Upgrading from an Older Version
* connector-j-installing-source::  Installing from the Development Source Tree

You can install the Connector/J package using either the binary or
source distribution. The binary distribution provides the easiest
method for installation; the source distribution enables you to
customize your installation further. With either solution, you must
manually add the Connector/J location to your Java `CLASSPATH'.

If you are upgrading from a previous version, read the upgrade
information before continuing. See *Note
connector-j-installing-upgrading::.

Connector/J is also available as part of the Maven project. More
information, and the Connector/J JAR files can be found at the Maven
repository (http://www.ibiblio.org/maven/).


File: manual.info,  Node: connector-j-binary-installation,  Next: connector-j-installing-classpath,  Prev: connector-j-installing,  Up: connector-j-installing

20.3.2.1 Installing Connector/J from a Binary Distribution
..........................................................

The easiest method of installation is to use the binary distribution of
the Connector/J package. The binary distribution is available either as
a Tar/Gzip or Zip file which you must extract to a suitable location
and then optionally make the information about the package available by
changing your `CLASSPATH' (see *Note
connector-j-installing-classpath::).

MySQL Connector/J is distributed as a .zip or .tar.gz archive
containing the sources, the class files, and the JAR archive named
`mysql-connector-java-[VERSION]-bin.jar', and starting with Connector/J
3.1.8 a debug build of the driver in a file named
`mysql-connector-java-[VERSION]-bin-g.jar'.

Starting with Connector/J 3.1.9, the `.class' files that constitute the
JAR files are only included as part of the driver JAR file.

You should not use the debug build of the driver unless instructed to
do so when reporting a problem or a bug, as it is not designed to be
run in production environments, and will have adverse performance
impact when used. The debug binary also depends on the Aspect/J runtime
library, which is located in the `src/lib/aspectjrt.jar' file that
comes with the Connector/J distribution.

You will need to use the appropriate graphical or command-line utility
to extract the distribution (for example, WinZip for the .zip archive,
and `tar' for the .tar.gz archive). Because there are potentially long
file names in the distribution, we use the GNU tar archive format. You
will need to use GNU tar (or an application that understands the GNU tar
archive format) to unpack the .tar.gz variant of the distribution.


File: manual.info,  Node: connector-j-installing-classpath,  Next: connector-j-installing-upgrading,  Prev: connector-j-binary-installation,  Up: connector-j-installing

20.3.2.2 Installing the Driver and Configuring the `CLASSPATH'
..............................................................

Once you have extracted the distribution archive, you can install the
driver by placing `mysql-connector-java-[version]-bin.jar 'in your
classpath, either by adding the full path to it to your `CLASSPATH'
environment variable, or by directly specifying it with the command
line switch -cp when starting your JVM.

If you are going to use the driver with the JDBC DriverManager, you
would use `com.mysql.jdbc.Driver' as the class that implements
java.sql.Driver.

You can set the `CLASSPATH' environment variable under UNIX, Linux or
Mac OS X either locally for a user within their `.profile', `.login' or
other login file. You can also set it globally by editing the global
`/etc/profile' file.

For example, under a C shell (csh, tcsh) you would add the Connector/J
driver to your `CLASSPATH' using the following:

     shell> setenv CLASSPATH /path/mysql-connector-java-[ver]-bin.jar:$CLASSPATH

Or with a Bourne-compatible shell (sh, ksh, bash):

     shell> export set CLASSPATH=/path/mysql-connector-java-[ver]-bin.jar:$CLASSPATH

Within Windows 2000, Windows XP, Windows Server 2003 and Windows Vista,
you must set the environment variable through the System Control Panel.

To use MySQL Connector/J with an application server such as GlassFish,
Tomcat or JBoss, read your vendor's documentation for more information
on how to configure third-party class libraries, as most application
servers ignore the `CLASSPATH' environment variable. For configuration
examples for some J2EE application servers, see *Note
connector-j-usagenotes-j2ee::. However, the authoritative source for
JDBC connection pool configuration information for your particular
application server is the documentation for that application server.

If you are developing servlets or JSPs, and your application server is
J2EE-compliant, you can put the driver's .jar file in the WEB-INF/lib
subdirectory of your webapp, as this is a standard location for third
party class libraries in J2EE web applications.

You can also use the MysqlDataSource or MysqlConnectionPoolDataSource
classes in the `com.mysql.jdbc.jdbc2.optional' package, if your J2EE
application server supports or requires them. Starting with Connector/J
5.0.0, the `javax.sql.XADataSource' interface is implemented using the
`com.mysql.jdbc.jdbc2.optional.MysqlXADataSource' class, which supports
XA distributed transactions when used in combination with MySQL server
version 5.0.

The various MysqlDataSource classes support the following parameters
(through standard set mutators):

   * user

   * password

   * serverName (see the previous section about fail-over hosts)

   * databaseName

   * port


File: manual.info,  Node: connector-j-installing-upgrading,  Next: connector-j-installing-source,  Prev: connector-j-installing-classpath,  Up: connector-j-installing

20.3.2.3 Upgrading from an Older Version
........................................

* Menu:

* connector-j-installing-upgrading-3-0-to-3-1::  Upgrading from MySQL Connector/J 3.0 to 3.1
* connector-j-installing-upgrading-5-1::  Upgrading to MySQL Connector/J 5.1.x
* connector-j-installing-upgrading-issues::  JDBC-Specific Issues When Upgrading to MySQL Server 4.1 or Newer

We try to keep the upgrade process as easy as possible, however as is
the case with any software, sometimes changes need to be made in new
versions to support new features, improve existing functionality, or
comply with new standards.

This section has information about what users who are upgrading from
one version of Connector/J to another (or to a new version of the MySQL
server, with respect to JDBC functionality) should be aware of.


File: manual.info,  Node: connector-j-installing-upgrading-3-0-to-3-1,  Next: connector-j-installing-upgrading-5-1,  Prev: connector-j-installing-upgrading,  Up: connector-j-installing-upgrading

20.3.2.4 Upgrading from MySQL Connector/J 3.0 to 3.1
....................................................

Connector/J 3.1 is designed to be backward-compatible with Connector/J
3.0 as much as possible. Major changes are isolated to new
functionality exposed in MySQL-4.1 and newer, which includes Unicode
character sets, server-side prepared statements, SQLState codes
returned in error messages by the server and various performance
enhancements that can be enabled or disabled using configuration
properties.

   * *Unicode Character Sets*: See the next section, as well as *Note
     charset::, for information on this new feature of MySQL. If you
     have something misconfigured, it will usually show up as an error
     with a message similar to `Illegal mix of collations'.

   * *Server-side Prepared Statements*: Connector/J 3.1 will
     automatically detect and use server-side prepared statements when
     they are available (MySQL server version 4.1.0 and newer).

     Starting with version 3.1.7, the driver scans SQL you are
     preparing using all variants of `Connection.prepareStatement()' to
     determine if it is a supported type of statement to prepare on the
     server side, and if it is not supported by the server, it instead
     prepares it as a client-side emulated prepared statement. You can
     disable this feature by passing emulateUnsupportedPstmts=false in
     your JDBC URL.

     If your application encounters issues with server-side prepared
     statements, you can revert to the older client-side emulated
     prepared statement code that is still presently used for MySQL
     servers older than 4.1.0 with the connection property
     useServerPrepStmts=false

   * *Datetimes* with all-zero components (`0000-00-00 ...'): These
     values can not be represented reliably in Java.  Connector/J 3.0.x
     always converted them to `NULL' when being read from a ResultSet.

     Connector/J 3.1 throws an exception by default when these values
     are encountered as this is the most correct behavior according to
     the JDBC and SQL standards. This behavior can be modified using the
     zeroDateTimeBehavior configuration property. The permissible
     values are:

        * `exception' (the default), which throws an SQLException with
          an SQLState of `S1009'.

        * `convertToNull', which returns `NULL' instead of the date.

        * `round', which rounds the date to the nearest closest value
          which is `0001-01-01'.

     Starting with Connector/J 3.1.7, `ResultSet.getString()' can be
     decoupled from this behavior using noDatetimeStringSync=true (the
     default value is `false') so that you can retrieve the unaltered
     all-zero value as a String. It should be noted that this also
     precludes using any time zone conversions, therefore the driver
     will not allow you to enable noDatetimeStringSync and useTimezone
     at the same time.

   * *New SQLState Codes*: Connector/J 3.1 uses SQL:1999 SQLState codes
     returned by the MySQL server (if supported), which are different
     from the legacy X/Open state codes that Connector/J 3.0 uses.  If
     connected to a MySQL server older than MySQL-4.1.0 (the oldest
     version to return SQLStates as part of the error code), the driver
     will use a built-in mapping. You can revert to the old mapping by
     using the configuration property useSqlStateCodes=false.

   * *`ResultSet.getString()'*: Calling `ResultSet.getString()' on a
     *Note `BLOB': blob. column will now return the address of the
     `byte[]' array that represents it, instead of a `String'
     representation of the *Note `BLOB': blob.  *Note `BLOB': blob.
     values have no character set, so they cannot be converted to
     `java.lang.String's without data loss or corruption.

     To store strings in MySQL with LOB behavior, use one of the *Note
     `TEXT': blob. types, which the driver will treat as a
     `java.sql.Clob'.

   * *Debug builds*: Starting with Connector/J 3.1.8 a debug build of
     the driver in a file named
     `mysql-connector-java-[VERSION]-bin-g.jar' is shipped alongside
     the normal binary jar file that is named
     `mysql-connector-java-[VERSION]-bin.jar'.

     Starting with Connector/J 3.1.9, we do not ship the .class files
     unbundled, they are only available in the JAR archives that ship
     with the driver.

     You should not use the debug build of the driver unless instructed
     to do so when reporting a problem or bug, as it is not designed to
     be run in production environments, and will have adverse
     performance impact when used. The debug binary also depends on the
     Aspect/J runtime library, which is located in the
     `src/lib/aspectjrt.jar' file that comes with the Connector/J
     distribution.


File: manual.info,  Node: connector-j-installing-upgrading-5-1,  Next: connector-j-installing-upgrading-issues,  Prev: connector-j-installing-upgrading-3-0-to-3-1,  Up: connector-j-installing-upgrading

20.3.2.5 Upgrading to MySQL Connector/J 5.1.x
.............................................

   * In Connector/J 5.0.x and earlier, the alias for a table in a *Note
     `SELECT': select. statement is returned when accessing the result
     set metadata using `ResultSetMetaData.getColumnName()'.  This
     behavior however is not JDBC compliant, and in Connector/J 5.1
     this behavior was changed so that the original table name, rather
     than the alias, is returned.

     The JDBC-compliant behavior is designed to let API users
     reconstruct the DML statement based on the metadata within
     `ResultSet' and `ResultSetMetaData'.

     You can get the alias for a column in a result set by calling
     `ResultSetMetaData.getColumnLabel()'.  To use the old noncompliant
     behavior with `ResultSetMetaData.getColumnName()', use the
     `useOldAliasMetadataBehavior' option and set the value to `true'.

     In Connector/J 5.0.x the default value of
     `useOldAliasMetadataBehavior' was true, but in Connector/J 5.1
     this was changed to a default value of false.


File: manual.info,  Node: connector-j-installing-upgrading-issues,  Prev: connector-j-installing-upgrading-5-1,  Up: connector-j-installing-upgrading

20.3.2.6 JDBC-Specific Issues When Upgrading to MySQL Server 4.1 or Newer
.........................................................................

   * _Using the UTF-8 Character Encoding_ - Prior to MySQL server
     version 4.1, the UTF-8 character encoding was not supported by the
     server, however the JDBC driver could use it, allowing storage of
     multiple character sets in latin1 tables on the server.

     Starting with MySQL-4.1, this functionality is deprecated.  If you
     have applications that rely on this functionality, and can not
     upgrade them to use the official Unicode character support in
     MySQL server version 4.1 or newer, you should add the following
     property to your connection URL:

     useOldUTF8Behavior=true

   * _Server-side Prepared Statements_ - Connector/J 3.1 will
     automatically detect and use server-side prepared statements when
     they are available (MySQL server version 4.1.0 and newer). If your
     application encounters issues with server-side prepared
     statements, you can revert to the older client-side emulated
     prepared statement code that is still presently used for MySQL
     servers older than 4.1.0 with the following connection property:

     useServerPrepStmts=false


File: manual.info,  Node: connector-j-installing-source,  Prev: connector-j-installing-upgrading,  Up: connector-j-installing

20.3.2.7 Installing from the Development Source Tree
....................................................

*Caution*:

Read this section only if you are interested in helping us test our new
code. If you just want to get MySQL Connector/J up and running on your
system, use a standard binary release distribution.

To install MySQL Connector/J from the development source tree, make
sure that you have the following prerequisites:

   * A Bazaar client, to check out the sources from our Launchpad
     repository (available from `http://bazaar-vcs.org/').

   * Apache Ant version 1.7 or newer (available from
     `http://ant.apache.org/').

   * JDK 1.4.2 or later. Although MySQL Connector/J can be be used with
     older JDKs, to compile it from source you must have at least JDK
     1.4.2. If you are building Connector/J 5.1 you will need JDK 1.6.x
     and an older JDK such as JDK 1.5.x.  You will then need to point
     your JAVA_HOME environment variable at the older installation.

The source code repository for MySQL Connector/J is located on
Launchpad at `https://code.launchpad.net/connectorj'.

To check out and compile a specific branch of MySQL Connector/J, follow
these steps:

  1. Check out the latest code from the branch that you want with one
     of the following commands.

     To check out the latest development branch use:

          shell> bzr branch lp:connectorj

     This creates a `connectorj' subdirectory in the current directory
     that contains the latest sources for the requested branch.

     To check out the latest 5.1 code use:

          shell> bzr branch lp:connectorj/5.1

     This will create a `5.1' subdirectory in the current directory
     containing the latest 5.1 code.

  2. If you are building Connector/J 5.1 make sure that you have both
     JDK 1.6.x installed and an older JDK such as JDK 1.5.x.  This is
     because Connector/J supports both JDBC 3.0 (which was prior to JDK
     1.6.x) and JDBC 4.0. Set your JAVA_HOME environment variable to
     the path of the older JDK installation.

  3. Change location to either the `connectorj' or `5.1' directory,
     depending on which branch you want to build, to make it your
     current working directory. For example:

          shell> cd connectorj

  4. If you are building Connector/J 5.1 you need to edit the
     `build.xml' to reflect the location of your JDK 1.6.x
     installation. The lines that you need to change are:

                      <property name="com.mysql.jdbc.java6.javac" value="C:\jvms\jdk1.6.0\bin\javac.exe" />
                      <property name="com.mysql.jdbc.java6.rtjar" value="C:\jvms\jdk1.6.0\jre\lib\rt.jar" />

     Alternatively, you can set the value of these property names
     through the Ant `-D' option.

  5. Issue the following command to compile the driver and create a
     `.jar' file suitable for installation:

          shell> ant dist

     This creates a `build' directory in the current directory, where
     all build output will go. A directory is created in the `build'
     directory that includes the version number of the sources you are
     building from. This directory contains the sources, compiled
     `.class' files, and a `.jar' file suitable for deployment. For
     other possible targets, including ones that will create a fully
     packaged distribution, issue the following command:

          shell> ant -projecthelp

  6. A newly created `.jar' file containing the JDBC driver will be
     placed in the directory `build/mysql-connector-java-[VERSION]'.

     Install the newly created JDBC driver as you would a binary `.jar'
     file that you download from MySQL by following the instructions in
     *Note connector-j-installing-classpath::.

A package containing both the binary and source code for Connector/J
5.1 can also be found at the following location: Connector/J 5.1
Download (http://dev.mysql.com/downloads/connector/j/5.1.html)


File: manual.info,  Node: connector-j-examples,  Next: connector-j-reference,  Prev: connector-j-installing,  Up: connector-j

20.3.3 Connector/J Examples
---------------------------

Examples of using Connector/J are located throughout this document,
this section provides a summary and links to these examples.

   * *Note connector-j-examples-connection-drivermanager::

   * *Note connector-j-examples-execute-select::

   * *Note connector-j-examples-stored-procedure::

   * *Note connector-j-examples-preparecall::

   * *Note connector-j-examples-output-param::

   * *Note connector-j-examples-callablestatement::

   * *Note connector-j-examples-retrieving-results-params::

   * *Note connector-j-examples-autoincrement-getgeneratedkeys::

   * *Note connector-j-examples-autoincrement-select::

   * *Note connector-j-examples-autoincrement-updateable-resultsets::

   * *Note connector-j-examples-connectionpool-j2ee::

   * *Note connector-j-examples-transaction-retry::


File: manual.info,  Node: connector-j-reference,  Next: connector-j-usagenotes,  Prev: connector-j-examples,  Up: connector-j

20.3.4 Connector/J (JDBC) Reference
-----------------------------------

* Menu:

* connector-j-reference-configuration-properties::  Driver/Datasource Class Names, URL Syntax and Configuration Properties for Connector/J
* connector-j-reference-implementation-notes::  JDBC API Implementation Notes
* connector-j-reference-type-conversions::  Java, JDBC and MySQL Types
* connector-j-reference-charsets::  Using Character Sets and Unicode
* connector-j-reference-using-ssl::  Connecting Securely Using SSL
* connector-j-reference-replication-connection::  Using Master/Slave Replication with ReplicationConnection
* connector-j-reference-error-sqlstates::  Mapping MySQL Error Numbers to SQLStates

This section of the manual contains reference material for MySQL
Connector/J, some of which is automatically generated during the
Connector/J build process.


File: manual.info,  Node: connector-j-reference-configuration-properties,  Next: connector-j-reference-implementation-notes,  Prev: connector-j-reference,  Up: connector-j-reference

20.3.4.1 Driver/Datasource Class Names, URL Syntax and Configuration Properties for Connector/J
...............................................................................................

The name of the class that implements java.sql.Driver in MySQL
Connector/J is `com.mysql.jdbc.Driver'. The `org.gjt.mm.mysql.Driver'
class name is also usable to remain backward-compatible with MM.MySQL.
You should use this class name when registering the driver, or when
otherwise configuring software to use MySQL Connector/J.

The JDBC URL format for MySQL Connector/J is as follows, with items in
square brackets ([, ]) being optional:

     jdbc:mysql://[host][,failoverhost...][:port]/[database] »
     [?propertyName1][=propertyValue1][&propertyName2][=propertyValue2]...

If the host name is not specified, it defaults to 127.0.0.1. If the
port is not specified, it defaults to 3306, the default port number for
MySQL servers.

     jdbc:mysql://[host:port],[host:port].../[database] »
     [?propertyName1][=propertyValue1][&propertyName2][=propertyValue2]...

Here is an example connection URL:

     jdbc:mysql://localhost:3306/sakila?profileSQL=true

If the database is not specified, the connection will be made with no
default database. In this case, you will need to either call the
`setCatalog()' method on the Connection instance or fully specify table
names using the database name (that is, `SELECT dbname.tablename.colname
FROM dbname.tablename...') in your SQL. Not specifying the database to
use upon connection is generally only useful when building tools that
work with multiple databases, such as GUI database managers.

*Note*:

JDBC clients should never employ the `USE database' statement to
specify the desired database, they should always use the
`Connection.setCatalog()' method instead.

MySQL Connector/J has fail-over support. This enables the driver to
fail-over to any number of slave hosts and still perform read-only
queries. Fail-over only happens when the connection is in an
`autoCommit(true)' state, because fail-over can not happen reliably
when a transaction is in progress. Most application servers and
connection pools set `autoCommit' to `true' at the end of every
transaction/connection use.

The fail-over functionality has the following behavior:

   * If the URL property autoReconnect is false: Failover only happens
     at connection initialization, and failback occurs when the driver
     determines that the first host has become available again.

   * If the URL property autoReconnect is true: Failover happens when
     the driver determines that the connection has failed (before
     _every_ query), and falls back to the first host when it determines
     that the host has become available again (after
     `queriesBeforeRetryMaster' queries have been issued).

In either case, whenever you are connected to a "failed-over" server,
the connection will be set to read-only state, so queries that would
modify data will have exceptions thrown (the query will *never* be
processed by the MySQL server).

Configuration properties define how Connector/J will make a connection
to a MySQL server. Unless otherwise noted, properties can be set for a
DataSource object or for a Connection object.

Configuration Properties can be set in one of the following ways:

   * Using the set*() methods on MySQL implementations of
     java.sql.DataSource (which is the preferred method when using
     implementations of java.sql.DataSource):

        * com.mysql.jdbc.jdbc2.optional.MysqlDataSource

        * com.mysql.jdbc.jdbc2.optional.MysqlConnectionPoolDataSource

   * As a key/value pair in the java.util.Properties instance passed to
     `DriverManager.getConnection()' or `Driver.connect()'

   * As a JDBC URL parameter in the URL given to
     `java.sql.DriverManager.getConnection()',
     `java.sql.Driver.connect()' or the MySQL implementations of the
     `javax.sql.DataSource' `setURL()' method.

     *Note*:

     If the mechanism you use to configure a JDBC URL is XML-based, you
     will need to use the XML character literal &amp; to separate
     configuration parameters, as the ampersand is a reserved character
     for XML.

The properties are listed in the following tables.

Connection/Authentication

* Property Name *      * Definition *                       *       *
                                                            Default Since
                                                            Value * Version
                                                                    *
user                   The user to connect as                       all
                                                                    versions
password               The password to use when connecting          all
                                                                    versions
socketFactory          The name of the class that the       com.mysql.jdbc.StandardSocketFactory3.0.3
                       driver should use for creating               
                       socket connections to the server.            
                       This class must implement the                
                       interface                                    
                       'com.mysql.jdbc.SocketFactory' and           
                       have public no-args constructor.             
connectTimeout         Timeout for socket connect (in       0       3.0.1
                       milliseconds), with 0 being no               
                       timeout.  Only works on JDK-1.4 or           
                       newer. Defaults to '0'.                      
socketTimeout          Timeout on network socket            0       3.0.1
                       operations (0, the default means no          
                       timeout).                                    
connectionLifecycleInterceptorsA comma-delimited list of classes            5.1.4
                       that implement                               
                       "com.mysql.jdbc.ConnectionLifecycleInterceptor"        
                       that should notified of connection           
                       lifecycle events (creation,                  
                       destruction, commit, rollback,               
                       setCatalog and setAutoCommit) and            
                       potentially alter the execution of           
                       these commands.                              
                       ConnectionLifecycleInterceptors are          
                       "stackable", more than one                   
                       interceptor may be specified via             
                       the configuration property as a              
                       comma-delimited list, with the               
                       interceptors executed in order from          
                       left to right.                               
useConfigs             Load the comma-delimited list of             3.1.5
                       configuration properties before              
                       parsing the URL or applying                  
                       user-specified properties. These             
                       configurations are explained in the          
                       'Configurations' of the                      
                       documentation.                               
interactiveClient      Set the CLIENT_INTERACTIVE flag,     false   3.1.0
                       which tells MySQL to timeout                 
                       connections based on                         
                       INTERACTIVE_TIMEOUT instead of               
                       WAIT_TIMEOUT                                 
localSocketAddress     Hostname or IP address given to              5.0.5
                       explicitly configure the interface           
                       that the driver will bind the                
                       client side of the TCP/IP                    
                       connection to when connecting.               
propertiesTransform    An implementation of                         3.1.4
                       com.mysql.jdbc.ConnectionPropertiesTransform        
                       that the driver will use to modify           
                       URL properties passed to the driver          
                       before attempting a connection               
useCompression         Use zlib compression when            false   3.0.17
                       communicating with the server                
                       (true/false)?  Defaults to 'false'.          

Networking

* Property Name *      * Definition *                       *       *
                                                            Default Since
                                                            Value * Version
                                                                    *
maxAllowedPacket       Maximum allowed packet size to send  -1      5.1.8
                       to server. If not set, the value of          
                       system variable                              
                       'max_allowed_packet' will be used to         
                       initialize this upon connecting.             
                       This value will not take effect if           
                       set larger than the value of                 
                       'max_allowed_packet'.                        
tcpKeepAlive           If connecting using TCP/IP, should   true    5.0.7
                       the driver set SO_KEEPALIVE?                 
tcpNoDelay             If connecting using TCP/IP, should   true    5.0.7
                       the driver set SO_TCP_NODELAY                
                       (disabling the Nagle Algorithm)?             
tcpRcvBuf              If connecting using TCP/IP, should   0       5.0.7
                       the driver set SO_RCV_BUF to the             
                       given value? The default value of            
                       '0', means use the platform default          
                       value for this property)                     
tcpSndBuf              If connecting using TCP/IP, should   0       5.0.7
                       the driver set SO_SND_BUF to the             
                       given value? The default value of            
                       '0', means use the platform default          
                       value for this property)                     
tcpTrafficClass        If connecting using TCP/IP, should   0       5.0.7
                       the driver set traffic class or              
                       type-of-service fields ?See the              
                       documentation for                            
                       java.net.Socket.setTrafficClass()            
                       for more information.                        

High Availability and Clustering

* Property Name *      * Definition *                       *       *
                                                            Default Since
                                                            Value * Version
                                                                    *
autoReconnect          Should the driver try to             false   1.1
                       re-establish stale and/or dead               
                       connections? If enabled the driver           
                       will throw an exception for a                
                       queries issued on a stale or dead            
                       connection, which belong to the              
                       current transaction, but will                
                       attempt reconnect before the next            
                       query issued on the connection in a          
                       new transaction. The use of this             
                       feature is not recommended, because          
                       it has side effects related to               
                       session state and data consistency           
                       when applications don't handle               
                       SQLExceptions properly, and is only          
                       designed to be used when you are             
                       unable to configure your                     
                       application to handle SQLExceptions          
                       resulting from dead and stale                
                       connections properly.                        
                       Alternatively, as a last option,             
                       investigate setting the MySQL                
                       server variable "wait_timeout" to a          
                       high value, rather than the default          
                       of 8 hours.                                  
autoReconnectForPools  Use a reconnection strategy          false   3.1.3
                       appropriate for connection pools             
                       (defaults to 'false')                        
failOverReadOnly       When failing over in autoReconnect   true    3.0.12
                       mode, should the connection be set           
                       to 'read-only'?                              
maxReconnects          Maximum number of reconnects to      3       1.1
                       attempt if autoReconnect is true,            
                       default is '3'.                              
reconnectAtTxEnd       If autoReconnect is set to true,     false   3.0.10
                       should the driver attempt                    
                       reconnections at the end of every            
                       transaction?                                 
retriesAllDown         When using loadbalancing, the        120     5.1.6
                       number of times the driver should            
                       cycle through available hosts,               
                       attempting to connect. Between               
                       cycles, the driver will pause for            
                       250ms if no servers are available.           
initialTimeout         If autoReconnect is enabled, the     2       1.1
                       initial time to wait between                 
                       re-connect attempts (in seconds,             
                       defaults to '2').                            
roundRobinLoadBalance  When autoReconnect is enabled, and   false   3.1.2
                       failoverReadonly is false, should we         
                       pick hosts to connect to on a                
                       round-robin basis?                           
queriesBeforeRetryMasterNumber of queries to issue before    50      3.0.2
                       falling back to master when failed           
                       over (when using multi-host                  
                       failover). Whichever condition is            
                       met first,                                   
                       'queriesBeforeRetryMaster' or                
                       'secondsBeforeRetryMaster' will              
                       cause an attempt to be made to               
                       reconnect to the master. Defaults            
                       to 50.                                       
secondsBeforeRetryMasterHow long should the driver wait,     30      3.0.2
                       when failed over, before attempting          
selfDestructOnPingMaxOperations=If set to a non-zero value, the     0       5.1.6
                       driver will report close the                 
                       connection and report failure when           
                       Connection.ping() or                         
                       Connection.isValid(int) is called            
                       if the connnection's count of                
                       commands sent to the server exceeds          
                       this value.                                  
selfDestructOnPingSecondsLifetimeIf set to a non-zero value, the      0       5.1.6
                       driver will report close the                 
                       connection and report failure when           
                       Connection.ping() or                         
                       Connection.isValid(int) is called            
                       if the connnection's lifetime                
                       exceeds this value.                          
resourceId             A globally unique name that                  5.0.1
                       identifies the resource that this            
                       datasource or connection is                  
                       connected to, used for                       
                       XAResource.isSameRM() when the               
                       driver can't determine this value            
                       based on hostnames used in the URL           

Security

* Property Name *      * Definition *                       *       *
                                                            Default Since
                                                            Value * Version
                                                                    *
allowMultiQueries      Allow the use of ';' to delimit      false   3.1.1
                       multiple queries during one                  
                       statement (true/false), defaults to          
                       'false'                                      
useSSL                 Use SSL when communicating with the  false   3.0.2
                       server (true/false), defaults to             
                       'false'                                      
requireSSL             Require SSL connection if            false   3.1.0
                       useSSL=true? (defaults to 'false').          
verifyServerCertificateIf "useSSL" is set to "true",        true    5.1.6
                       should the driver verify the                 
                       server's certificate? When using             
                       this feature, the keystore                   
                       parameters should be specified by            
                       the "clientCertificateKeyStore*"             
                       properties, rather than system               
                       properties.                                  
clientCertificateKeyStoreUrlURL to the client certificate                5.1.0
                       KeyStore (if not specified, use              
                       defaults)                                    
clientCertificateKeyStoreTypeKeyStore type for client             JKS     5.1.0
                       certificates (NULL or empty means            
                       use the default, which is "JKS".             
                       Standard keystore types supported            
                       by the JVM are "JKS" and "PKCS12",           
                       your environment may have more               
                       available depending on what                  
                       security products are installed and          
                       available to the JVM.                        
clientCertificateKeyStorePasswordPassword for the client                      5.1.0
                       certificates KeyStore                        
trustCertificateKeyStoreUrlURL to the trusted root certificate          5.1.0
                       KeyStore (if not specified, use              
                       defaults)                                    
trustCertificateKeyStoreTypeKeyStore type for trusted root       JKS     5.1.0
                       certificates (NULL or empty means            
                       use the default, which is "JKS".             
                       Standard keystore types supported            
                       by the JVM are "JKS" and "PKCS12",           
                       your environment may have more               
                       available depending on what                  
                       security products are installed and          
                       available to the JVM.                        
trustCertificateKeyStorePasswordPassword for the trusted root                5.1.0
                       certificates KeyStore                        
allowLoadLocalInfile   Should the driver allow use of       true    3.0.3
                       'LOAD DATA LOCAL INFILE...'                  
                       (defaults to 'true').                        
allowUrlInLocalInfile  Should the driver allow URLs in      false   3.1.4
                       'LOAD DATA LOCAL INFILE' statements?         
paranoid               Take measures to prevent exposure    false   3.0.1
                       sensitive information in error               
                       messages and clear data structures           
                       holding sensitive data when                  
                       possible? (defaults to 'false')              
passwordCharacterEncodingWhat character encoding is used for          5.1.7
                       passwords? Leaving this set to the           
                       default value (null), uses the               
                       platform character set, which works          
                       for ISO8859_1 (i.e. "latin1")                
                       passwords. For passwords in other            
                       character encodings, the encoding            
                       will have to be specified with this          
                       property, as it's not possible for           
                       the driver to auto-detect this.              

Performance Extensions

* Property Name *      * Definition *                       *       *
                                                            Default Since
                                                            Value * Version
                                                                    *
callableStmtCacheSize  If 'cacheCallableStmts' is enabled,  100     3.1.2
                       how many callable statements should          
                       be cached?                                   
metadataCacheSize      The number of queries to cache       50      3.1.1
                       ResultSetMetadata for if                     
                       cacheResultSetMetaData is set to             
                       'true' (default 50)                          
useLocalSessionState   Should the driver refer to the       false   3.1.7
                       internal values of autocommit and            
                       transaction isolation that are set           
                       by Connection.setAutoCommit() and            
                       Connection.setTransactionIsolation()         
                       and transaction state as maintained          
                       by the protocol, rather than                 
                       querying the database or blindly             
                       sending commands to the database             
                       for commit() or rollback() method            
                       calls?                                       
useLocalTransactionStateShould the driver use the            false   5.1.7
                       in-transaction state provided by             
                       the MySQL protocol to determine if           
                       a commit() or rollback() should              
                       actually be sent to the database?            
prepStmtCacheSize      If prepared statement caching is     25      3.0.10
                       enabled, how many prepared                   
                       statements should be cached?                 
prepStmtCacheSqlLimit  If prepared statement caching is     256     3.0.10
                       enabled, what's the largest SQL the          
                       driver will cache the parsing for?           
alwaysSendSetIsolation Should the driver always             true    3.1.7
                       communicate with the database when           
                       Connection.setTransactionIsolation()         
                       is called? If set to false, the              
                       driver will only communicate with            
                       the database when the requested              
                       transaction isolation is different           
                       than the whichever is newer, the             
                       last value that was set via                  
                       Connection.setTransactionIsolation(),        
                       or the value that was read from the          
                       server when the connection was               
                       established. Note that                       
                       useLocalSessionState=true will               
                       force the same behavior as                   
                       alwaysSendSetIsolation=false,                
                       regardless of how                            
                       alwaysSendSetIsolation is set.               
maintainTimeStats      Should the driver maintain various   true    3.1.9
                       internal timers to enable idle time          
                       calculations as well as more                 
                       verbose error messages when the              
                       connection to the server fails?              
                       Setting this property to false               
                       removes at least two calls to                
                       System.getCurrentTimeMillis() per            
                       query.                                       
useCursorFetch         If connected to MySQL > 5.0.2, and   false   5.0.0
                       setFetchSize() > 0 on a statement,           
                       should that statement use                    
                       cursor-based fetching to retrieve            
                       rows?                                        
blobSendChunkSize      Chunk to use when sending            1048576 3.1.9
                       BLOB/CLOBs via                               
                       ServerPreparedStatements                     
cacheCallableStmts     Should the driver cache the parsing  false   3.1.2
                       stage of CallableStatements                  
cachePrepStmts         Should the driver cache the parsing  false   3.0.10
                       stage of PreparedStatements of               
                       client-side prepared statements,             
                       the "check" for suitability of               
                       server-side prepared and server-side         
                       prepared statements themselves?              
cacheResultSetMetadata Should the driver cache              false   3.1.1
                       ResultSetMetaData for Statements and         
                       PreparedStatements? (Req. JDK-1.4+,          
                       true/false, default 'false')                 
cacheServerConfigurationShould the driver cache the results  false   3.1.5
                       of 'SHOW VARIABLES' and 'SHOW                
                       COLLATION' on a per-URL basis?               
defaultFetchSize       The driver will call                 0       3.1.9
                       setFetchSize(n) with this value on           
                       all newly-created Statements                 
dontTrackOpenResources The JDBC specification requires the  false   3.1.7
                       driver to automatically track and            
                       close resources, however if your             
                       application doesn't do a good job            
                       of explicitly calling close() on             
                       statements or result sets, this can          
                       cause memory leakage. Setting this           
                       property to true relaxes this                
                       constraint, and can be more memory           
                       efficient for some applications.             
dynamicCalendars       Should the driver retrieve the       false   3.1.5
                       default calendar when required, or           
                       cache it per connection/session?             
elideSetAutoCommits    If using MySQL-4.1 or newer, should  false   3.1.3
                       the driver only issue 'set                   
                       autocommit=n' queries when the               
                       server's state doesn't match the             
                       requested state by                           
                       Connection.setAutoCommit(boolean)?           
enableQueryTimeouts    When enabled, query timeouts set     true    5.0.6
                       via Statement.setQueryTimeout() use          
                       a shared java.util.Timer instance            
                       for scheduling. Even if the timeout          
                       doesn't expire before the query is           
                       processed, there will be memory              
                       used by the TimerTask for the given          
                       timeout which won't be reclaimed             
                       until the time the timeout would             
                       have expired if it hadn't been               
                       cancelled by the driver. High-load           
                       environments might want to consider          
                       disabling this functionality.                
holdResultsOpenOverStatementCloseShould the driver close result sets  false   3.1.7
                       on Statement.close() as required by          
                       the JDBC specification?                      
largeRowSizeThreshold  What size result set row should the  2048    5.1.1
                       JDBC driver consider "large", and            
                       thus use a more memory-efficient             
                       way of representing the row                  
                       internally?                                  
loadBalanceStrategy    If using a load-balanced connection  random  5.0.6
                       to connect to SQL nodes in a MySQL           
                       Cluster/NDB configuration (by using          
                       the URL prefix                               
                       "jdbc:mysql:loadbalance://"), which          
                       load balancing algorithm should the          
                       driver use: (1) "random" - the               
                       driver will pick a random host for           
                       each request. This tends to work             
                       better than round-robin, as the              
                       randomness will somewhat account             
                       for spreading loads where requests           
                       vary in response time, while                 
                       round-robin can sometimes lead to            
                       overloaded nodes if there are                
                       variations in response times across          
                       the workload. (2)                            
                       "bestResponseTime" - the driver              
                       will route the request to the host           
                       that had the best response time for          
                       the previous transaction.                    
locatorFetchBufferSize If 'emulateLocators' is configured   1048576 3.2.1
                       to 'true', what size buffer should           
                       be used when fetching BLOB data for          
                       getBinaryInputStream?                        
rewriteBatchedStatementsShould the driver use multiqueries   false   3.1.13
                       (irregardless of the setting of              
                       "allowMultiQueries") as well as              
                       rewriting of prepared statements             
                       for INSERT into multi-value inserts          
                       when executeBatch() is called?               
                       Notice that this has the potential           
                       for SQL injection if using plain             
                       java.sql.Statements and your code            
                       doesn't sanitize input correctly.            
                       Notice that for prepared statements,         
                       server-side prepared statements can          
                       not currently take advantage of              
                       this rewrite option, and that if             
                       you don't specify stream lengths             
                       when using                                   
                       PreparedStatement.set*Stream(), the          
                       driver won't be able to determine            
                       the optimum number of parameters             
                       per batch and you might receive an           
                       error from the driver that the               
                       resultant packet is too large.               
                       Statement.getGeneratedKeys() for             
                       these rewritten statements only              
                       works when the entire batch includes         
                       INSERT statements.                           
useDirectRowUnpack     Use newer result set row unpacking   true    5.1.1
                       code that skips a copy from network          
                       buffers to a MySQL packet instance           
                       and instead reads directly into the          
                       result set row data buffers.                 
useDynamicCharsetInfo  Should the driver use a              true    5.0.6
                       per-connection cache of character            
                       set information queried from the             
                       server when necessary, or use a              
                       built-in static mapping that is              
                       more efficient, but isn't aware of           
                       custom character sets or character           
                       sets implemented after the release           
                       of the JDBC driver?                          
useFastDateParsing     Use internal                         true    5.0.5
                       String->Date/Time/Timestamp                  
                       conversion routines to avoid                 
                       excessive object creation?                   
useFastIntParsing      Use internal String->Integer         true    3.1.4
                       conversion routines to avoid                 
                       excessive object creation?                   
useJvmCharsetConvertersAlways use the character encoding    false   5.0.1
                       routines built into the JVM, rather          
                       than using lookup tables for                 
                       single-byte character sets?                  
useReadAheadInput      Use newer, optimized non-blocking,   true    3.1.5
                       buffered input stream when reading           
                       from the server?                             

Debugging/Profiling

* Property Name *      * Definition *                       *       *
                                                            Default Since
                                                            Value * Version
                                                                    *
logger                 The name of a class that implements  com.mysql.jdbc.log.StandardLogger3.1.1
                       "com.mysql.jdbc.log.Log" that will           
                       be used to log messages to.                  
                       (default is                                  
                       "com.mysql.jdbc.log.StandardLogger",         
                       which logs to STDERR)                        
gatherPerfMetrics      Should the driver gather             false   3.1.2
                       performance metrics, and report              
                       them via the configured logger               
                       every 'reportMetricsIntervalMillis'          
                       milliseconds?                                
profileSQL             Trace queries and their              false   3.1.0
                       execution/fetch times to the                 
                       configured logger (true/false)               
                       defaults to 'false'                          
profileSql             Deprecated, use 'profileSQL'                 2.0.14
                       instead. Trace queries and their             
                       execution/fetch times on STDERR              
                       (true/false) defaults to 'false'             
reportMetricsIntervalMillisIf 'gatherPerfMetrics' is enabled,   30000   3.1.2
                       how often should they be logged (in          
                       ms)?                                         
maxQuerySizeToLog      Controls the maximum length/size of  2048    3.1.3
                       a query that will get logged when            
                       profiling or tracing                         
packetDebugBufferSize  The maximum number of packets to     20      3.1.3
                       retain when 'enablePacketDebug' is           
                       true                                         
slowQueryThresholdMillisIf 'logSlowQueries' is enabled, how  2000    3.1.2
                       long should a query (in ms) before           
                       it is logged as 'slow'?                      
slowQueryThresholdNanosIf 'useNanosForElapsedTime' is set   0       5.0.7
                       to true, and this property is set to         
                       a non-zero value, the driver will            
                       use this threshold (in nanosecond            
                       units) to determine if a query was           
                       slow.                                        
useUsageAdvisor        Should the driver issue 'usage'      false   3.1.1
                       warnings advising proper and                 
                       efficient usage of JDBC and MySQL            
                       Connector/J to the log (true/false,          
                       defaults to 'false')?                        
autoGenerateTestcaseScriptShould the driver dump the SQL it    false   3.1.9
                       is executing, including server-side          
                       prepared statements to STDERR?               
autoSlowLog            Instead of using                     true    5.1.4
                       slowQueryThreshold* to determine if          
                       a query is slow enough to be                 
                       logged, maintain statistics that             
                       allow the driver to determine                
                       queries that are outside the 99th            
                       percentile?                                  
clientInfoProvider     The name of a class that implements  com.mysql.jdbc.JDBC4CommentClientInfoProvider5.1.0
                       the                                          
                       com.mysql.jdbc.JDBC4ClientInfoProvider        
                       interface in order to support                
                       JDBC-4.0's                                   
                       Connection.get/setClientInfo()               
                       methods                                      
dumpMetadataOnColumnNotFoundShould the driver dump the           false   3.1.13
                       field-level metadata of a result             
                       set into the exception message when          
                       ResultSet.findColumn() fails?                
dumpQueriesOnException Should the driver dump the contents  false   3.1.3
                       of the query sent to the server in           
                       the message for SQLExceptions?               
enablePacketDebug      When enabled, a ring-buffer of       false   3.1.3
                       'packetDebugBufferSize' packets              
                       will be kept, and dumped when                
                       exceptions are thrown in key areas           
                       in the driver's code                         
explainSlowQueries     If 'logSlowQueries' is enabled,      false   3.1.2
                       should the driver automatically              
                       issue an 'EXPLAIN' on the server             
                       and send the results to the                  
                       configured log at a WARN level?              
includeInnodbStatusInDeadlockExceptionsInclude the output of "SHOW ENGINE   false   5.0.7
                       INNODB STATUS" in exception messages         
                       when deadlock exceptions are                 
                       detected?                                    
includeThreadDumpInDeadlockExceptionsInclude a current Java thread dump   false   5.1.15
                       in exception messages when deadlock          
                       exceptions are detected?                     
includeThreadNamesAsStatementCommentInclude the name of the current      false   5.1.15
                       thread as a comment visible in "SHOW         
                       PROCESSLIST", or in Innodb deadlock          
                       dumps, useful in correlation with            
                       "includeInnodbStatusInDeadlockExceptions=true"        
                       and                                          
                       "includeThreadDumpInDeadlockExceptions=true".        
logSlowQueries         Should queries that take longer      false   3.1.2
                       than 'slowQueryThresholdMillis' be           
                       logged?                                      
logXaCommands          Should the driver log XA commands    false   5.0.5
                       sent by MysqlXaConnection to the             
                       server, at the DEBUG level of                
                       logging?                                     
profilerEventHandler   Name of a class that implements the  com.mysql.jdbc.profiler.LoggingProfilerEventHandler5.1.6
                       interface                                    
                       com.mysql.jdbc.profiler.ProfilerEventHandler        
                       that will be used to handle                  
                       profiling/tracing events.                    
resultSetSizeThreshold If the usage advisor is enabled,     100     5.0.5
                       how many rows should a result set            
                       contain before the driver warns              
                       that it is suspiciously large?               
traceProtocol          Should trace-level network protocol  false   3.1.2
                       be logged?                                   
useNanosForElapsedTime For profiling/debugging              false   5.0.7
                       functionality that measures elapsed          
                       time, should the driver try to use           
                       nanoseconds resolution if available          
                       (JDK >= 1.5)?                                

Miscellaneous

* Property Name *      * Definition *                       *       *
                                                            Default Since
                                                            Value * Version
                                                                    *
useUnicode             Should the driver use Unicode        true    1.1g
                       character encodings when handling            
                       strings?  Should only be used when           
                       the driver can't determine the               
                       character set mapping, or you are            
                       trying to 'force' the driver to use          
                       a character set that MySQL either            
                       doesn't natively support (such as            
                       UTF-8), true/false, defaults to              
                       'true'                                       
characterEncoding      If 'useUnicode' is set to true,              1.1g
                       what character encoding should the           
                       driver use when dealing with                 
                       strings? (defaults is to                     
                       'autodetect')                                
characterSetResults    Character set to tell the server to          3.0.13
                       return results as.                           
connectionCollation    If set, tells the server to use              3.0.13
                       this collation via 'set                      
                       collation_connection'                        
useBlobToStoreUTF8OutsideBMPTells the driver to treat            false   5.1.3
                       [MEDIUM/LONG]BLOB columns as                 
                       [LONG]VARCHAR columns holding text           
                       encoded in UTF-8 that has                    
                       characters outside the BMP (4-byte           
                       encodings), which MySQL server               
                       can't handle natively.                       
utf8OutsideBmpExcludedColumnNamePatternWhen "useBlobToStoreUTF8OutsideBMP"          5.1.3
                       is set to "true", column names               
                       matching the given regex will still          
                       be treated as BLOBs unless they              
                       match the regex specified for                
                       "utf8OutsideBmpIncludedColumnNamePattern".        
                       The regex must follow the patterns           
                       used for the java.util.regex                 
                       package.                                     
utf8OutsideBmpIncludedColumnNamePatternUsed to specify exclusion rules to           5.1.3
                       "utf8OutsideBmpExcludedColumnNamePattern".        
                       The regex must follow the patterns           
                       used for the java.util.regex                 
                       package.                                     
loadBalanceEnableJMX   Enables JMX-based management of      false   5.1.13
                       load-balanced connection groups,             
                       including live addition/removal of           
                       hosts from load-balancing pool.              
sessionVariables       A comma-separated list of                    3.1.8
                       name/value pairs to be sent as SET           
                       SESSION ...  to the server when the          
                       driver connects.                             
useColumnNamesInFindColumnPrior to JDBC-4.0, the JDBC          false   5.1.7
                       specification had a bug related to           
                       what could be given as a "column             
                       name" to ResultSet methods like              
                       findColumn(), or getters that took           
                       a String property. JDBC-4.0                  
                       clarified "column name" to mean the          
                       label, as given in an "AS" clause            
                       and returned by                              
                       ResultSetMetaData.getColumnLabel(),          
                       and if no AS clause, the column              
                       name. Setting this property to               
                       "true" will give behavior that is            
                       congruent to JDBC-3.0 and earlier            
                       versions of the JDBC specification,          
                       but which because of the                     
                       specification bug could give                 
                       unexpected results.  This property           
                       is preferred over                            
                       "useOldAliasMetadataBehavior"                
                       unless you need the specific                 
                       behavior that it provides with               
                       respect to ResultSetMetadata.                
allowNanAndInf         Should the driver allow NaN or +/-   false   3.1.5
                       INF values in                                
                       PreparedStatement.setDouble()?               
autoClosePStmtStreams  Should the driver automatically      false   3.1.12
                       call .close() on streams/readers             
                       passed as arguments via set*()               
                       methods?                                     
autoDeserialize        Should the driver automatically      false   3.1.5
                       detect and de-serialize objects              
                       stored in BLOB fields?                       
blobsAreStrings        Should the driver always treat       false   5.0.8
                       BLOBs as Strings - specifically to           
                       work around dubious metadata                 
                       returned by the server for GROUP BY          
                       clauses?                                     
capitalizeTypeNames    Capitalize type names in             true    2.0.7
                       DatabaseMetaData? (usually only              
                       useful when using WebObjects,                
                       true/false, defaults to 'false')             
clobCharacterEncoding  The character encoding to use for            5.0.0
                       sending and retrieving TEXT,                 
                       MEDIUMTEXT and LONGTEXT values               
                       instead of the configured                    
                       connection characterEncoding                 
clobberStreamingResultsThis will cause a 'streaming'        false   3.0.9
                       ResultSet to be automatically                
                       closed, and any outstanding data             
                       still streaming from the server to           
                       be discarded if another query is             
                       executed before all the data has             
                       been read from the server.                   
compensateOnDuplicateKeyUpdateCountsShould the driver compensate for     false   5.1.7
                       the update counts of "ON DUPLICATE           
                       KEY" INSERT statements (2 = 1, 0 =           
                       1) when using prepared statements?           
continueBatchOnError   Should the driver continue           true    3.0.3
                       processing batch commands if one             
                       statement fails. The JDBC spec               
                       allows either way (defaults to               
                       'true').                                     
createDatabaseIfNotExistCreates the database given in the    false   3.1.9
                       URL if it doesn't yet exist. Assumes         
                       the configured user has permissions          
                       to create databases.                         
emptyStringsConvertToZeroShould the driver allow conversions  true    3.1.8
                       from empty string fields to numeric          
                       values of '0'?                               
emulateLocators        Should the driver emulate            false   3.1.0
                       java.sql.Blobs with locators? With           
                       this feature enabled, the driver             
                       will delay loading the actual Blob           
                       data until the one of the retrieval          
                       methods (getInputStream(),                   
                       getBytes(), and so forth) on the             
                       blob data stream has been accessed.          
                       For this to work, you must use a             
                       column alias with the value of the           
                       column to the actual name of the             
                       Blob. The feature also has the               
                       following restrictions: The SELECT           
                       that created the result set must             
                       reference only one table, the table          
                       must have a primary key; the SELECT          
                       must alias the original blob column          
                       name, specified as a string, to an           
                       alternate name; the SELECT must              
                       cover all columns that make up the           
                       primary key.                                 
emulateUnsupportedPstmtsShould the driver detect prepared    true    3.1.7
                       statements that are not supported by         
                       the server, and replace them with            
                       client-side emulated versions?               
exceptionInterceptors  Comma-delimited list of classes              5.1.8
                       that implement                               
                       com.mysql.jdbc.ExceptionInterceptor.         
                       These classes will be instantiated           
                       one per Connection instance, and all         
                       SQLExceptions thrown by the driver           
                       will be allowed to be intercepted            
                       by these interceptors, in a chained          
                       fashion, with the first class                
                       listed as the head of the chain.             
functionsNeverReturnBlobsShould the driver always treat data  false   5.0.8
                       from functions returning BLOBs as            
                       Strings - specifically to work               
                       around dubious metadata returned by          
                       the server for GROUP BY clauses?             
generateSimpleParameterMetadataShould the driver generate           false   5.0.5
                       simplified parameter metadata for            
                       PreparedStatements when no metadata          
                       is available either because the              
                       server couldn't support preparing            
                       the statement, or server-side                
                       prepared statements are disabled?            
ignoreNonTxTables      Ignore non-transactional table       false   3.0.9
                       warning for rollback? (defaults to           
                       'false').                                    
jdbcCompliantTruncationShould the driver throw              true    3.1.2
                       java.sql.DataTruncation exceptions           
                       when data is truncated as is                 
                       required by the JDBC specification           
                       when connected to a server that              
                       supports warnings (MySQL 4.1.0 and           
                       newer)? This property has no effect          
                       if the server sql-mode includes              
                       STRICT_TRANS_TABLES.                         
loadBalanceAutoCommitStatementRegexWhen load-balancing is enabled for           5.1.15
                       auto-commit statements (via                  
                       loadBalanceAutoCommitStatementThreshold),        
                       the statement counter will only              
                       increment when the SQL matches the           
                       regular expression. By default,              
                       every statement issued matches.              
loadBalanceAutoCommitStatementThresholdWhen auto-commit is enabled, the     0       5.1.15
                       number of statements which should be         
                       executed before triggering                   
                       load-balancing to rebalance.                 
                       Default value of 0 causes                    
                       load-balanced connections to only            
                       rebalance when exceptions are                
                       encountered, or auto-commit is               
                       disabled and transactions are                
                       explicitly committed or rolled back.         
loadBalanceBlacklistTimeoutTime in milliseconds between checks  0       5.1.0
                       of servers which are unavailable.            
loadBalanceConnectionGroupLogical group of load-balanced               5.1.13
                       connections within a classloader,            
                       used to manage different groups              
                       independently. If not specified,             
                       live management of load-balanced             
                       connections is disabled.                     
loadBalanceExceptionCheckerFully-qualified class name of        com.mysql.jdbc.StandardLoadBalanceExceptionChecker5.1.13
                       custom exception checker. The class          
                       must implement                               
                       com.mysql.jdbc.LoadBalanceExceptionChecker        
                       interface, and is used to inspect            
                       SQLExceptions and determine whether          
                       they should trigger fail-over to             
                       another host in a load-balanced              
                       deployment.                                  
loadBalancePingTimeout Time in milliseconds to wait for     0       5.1.13
                       ping response from each of                   
                       load-balanced physical connections           
                       when using load-balanced Connection.         
loadBalanceSQLExceptionSubclassFailoverComma-delimited list of                      5.1.13
                       classes/interfaces used by default           
                       load-balanced exception checker to           
                       determine whether a given                    
                       SQLException should trigger                  
                       failover. The comparison is done             
                       using                                        
                       Class.isInstance(SQLException)               
                       using the thrown SQLException.               
loadBalanceSQLStateFailoverComma-delimited list of SQLState             5.1.13
                       codes used by default load-balanced          
                       exception checker to determine               
                       whether a given SQLException should          
                       trigger failover. The SQLState of a          
                       given SQLException is evaluated to           
                       determine whether it begins with             
                       any value in the comma-delimited             
                       list.                                        
loadBalanceValidateConnectionOnSwapServerShould the load-balanced Connection  false   5.1.13
                       explicitly check whether the                 
                       connection is live when swapping to          
                       a new physical connection at                 
                       commit/rollback?                             
maxRows                The maximum number of rows to        -1      all
                       return (0, the default means return          versions
                       all rows).                                   
netTimeoutForStreamingResultsWhat value should the driver         600     5.1.0
                       automatically set the server setting         
                       'net_write_timeout' to when the              
                       streaming result sets feature is in          
                       use? (value has unit of seconds,             
                       the value '0' means the driver will          
                       not try and adjust this value)               
noAccessToProcedureBodiesWhen determining procedure           false   5.0.3
                       parameter types for                          
                       CallableStatements, and the                  
                       connected user can't access                  
                       procedure bodies through "SHOW               
                       CREATE PROCEDURE" or select on               
                       mysql.proc should the driver                 
                       instead create basic metadata (all           
                       parameters reported as IN VARCHARs,          
                       but allowing registerOutParameter()          
                       to be called on them anyway)                 
                       instead of throwing an exception?            
noDatetimeStringSync   Don't ensure that                    false   3.1.7
                       ResultSet.getDatetimeType().toString().equals(ResultSet.getString())        
noTimezoneConversionForTimeTypeDon't convert TIME values using the  false   5.0.0
                       server timezone if                           
                       'useTimezone'='true'                         
nullCatalogMeansCurrentWhen DatabaseMetadataMethods ask     true    3.1.8
                       for a 'catalog' parameter, does the          
                       value null mean use the current              
                       catalog? (this is not                        
                       JDBC-compliant, but follows legacy           
                       behavior from earlier versions of            
                       the driver)                                  
nullNamePatternMatchesAllShould DatabaseMetaData methods      true    3.1.8
                       that accept *pattern parameters              
                       treat null the same as '%' (this is          
                       not JDBC-compliant, however older            
                       versions of the driver accepted this         
                       departure from the specification)            
overrideSupportsIntegrityEnhancementFacilityShould the driver return "true" for  false   3.1.12
                       DatabaseMetaData.supportsIntegrityEnhancementFacility()        
                       even if the database doesn't                 
                       support it to workaround                     
                       applications that require this               
                       method to return "true" to signal            
                       support of foreign keys, even                
                       though the SQL specification states          
                       that this facility contains much             
                       more than just foreign key support           
                       (one such application being                  
                       OpenOffice)?                                 
padCharsWithSpace      If a result set column has the CHAR  false   5.0.6
                       type and the value does not fill the         
                       amount of characters specified in            
                       the DDL for the column, should the           
                       driver pad the remaining characters          
                       with space (for ANSI compliance)?            
pedantic               Follow the JDBC spec to the letter.  false   3.0.0
pinGlobalTxToPhysicalConnectionWhen using XAConnections, should     false   5.0.1
                       the driver ensure that operations            
                       on a given XID are always routed to          
                       the same physical connection? This           
                       allows the XAConnection to support           
                       "XA START ... JOIN" after "XA END"           
                       has been called                              
populateInsertRowWithDefaultValuesWhen using ResultSets that are       false   5.0.5
                       CONCUR_UPDATABLE, should the driver          
                       pre-populate the "insert" row with           
                       default values from the DDL for the          
                       table used in the query so those             
                       values are immediately available             
                       for ResultSet accessors? This                
                       functionality requires a call to             
                       the database for metadata each time          
                       a result set of this type is                 
                       created.  If disabled (the                   
                       default), the default values will be         
                       populated by the an internal call            
                       to refreshRow() which pulls back             
                       default values and/or values                 
                       changed by triggers.                         
processEscapeCodesForPrepStmtsShould the driver process escape     true    3.1.12
                       codes in queries that are prepared?          
queryTimeoutKillsConnectionIf the timeout given in              false   5.1.9
                       Statement.setQueryTimeout()                  
                       expires, should the driver forcibly          
                       abort the Connection instead of              
                       attempting to abort the query?               
relaxAutoCommit        If the version of MySQL the driver   false   2.0.13
                       connects to does not support                 
                       transactions, still allow calls to           
                       commit(), rollback() and                     
                       setAutoCommit() (true/false,                 
                       defaults to 'false')?                        
retainStatementAfterResultSetCloseShould the driver retain the         false   3.1.11
                       Statement reference in a ResultSet           
                       after ResultSet.close() has been             
                       called. This is not JDBC-compliant           
                       after JDBC-4.0.                              
rollbackOnPooledClose  Should the driver issue a            true    3.0.15
                       rollback() when the logical                  
                       connection in a pool is closed?              
runningCTS13           Enables workarounds for bugs in      false   3.1.7
                       Sun's JDBC compliance testsuite              
                       version 1.3                                  
serverTimezone         Override detection/mapping of                3.0.2
                       timezone. Used when timezone from            
                       server doesn't map to Java timezone          
statementInterceptors  A comma-delimited list of classes            5.1.1
                       that implement                               
                       "com.mysql.jdbc.StatementInterceptor"        
                       that should be placed "in between"           
                       query execution to influence the             
                       results. StatementInterceptors are           
                       "chainable", the results returned            
                       by the "current" interceptor will be         
                       passed on to the next in in the              
                       chain, from left-to-right order, as          
                       specified in this property.                  
strictFloatingPoint    Used only in older versions of       false   3.0.0
                       compliance test                              
strictUpdates          Should the driver do strict          true    3.0.4
                       checking (all primary keys                   
                       selected) of updatable result sets           
                       (true, false, defaults to 'true')?           
tinyInt1isBit          Should the driver treat the          true    3.0.16
                       datatype TINYINT(1) as the BIT type          
                       (because the server silently                 
                       converts BIT -> TINYINT(1) when              
                       creating tables)?                            
transformedBitIsBooleanIf the driver converts TINYINT(1)    false   3.1.9
                       to a different type, should it use           
                       BOOLEAN instead of BIT for future            
                       compatibility with MySQL-5.0, as             
                       MySQL-5.0 has a BIT type?                    
treatUtilDateAsTimestampShould the driver treat              true    5.0.5
                       java.util.Date as a TIMESTAMP for            
                       the purposes of                              
                       PreparedStatement.setObject()?               
ultraDevHack           Create PreparedStatements for        false   2.0.3
                       prepareCall() when required, because         
                       UltraDev is broken and issues a              
                       prepareCall() for _all_ statements?          
                       (true/false, defaults to 'false')            
useAffectedRows        Don't set the CLIENT_FOUND_ROWS      false   5.1.7
                       flag when connecting to the server           
                       (not JDBC-compliant, will break              
                       most applications that rely on               
                       "found" rows vs. "affected rows"             
                       for DML statements), but does cause          
                       "correct" update counts from                 
                       "INSERT ...  ON DUPLICATE KEY                
                       UPDATE" statements to be returned by         
                       the server.                                  
useGmtMillisForDatetimesConvert between session timezone     false   3.1.12
                       and GMT before creating Date and             
                       Timestamp instances (value of                
                       "false" is legacy behavior, "true"           
                       leads to more JDBC-compliant                 
                       behavior.                                    
useHostsInPrivileges   Add '@hostname' to users in          true    3.0.2
                       DatabaseMetaData.getColumn/TablePrivileges()        
                       (true/false), defaults to 'true'.            
useInformationSchema   When connected to MySQL-5.0.7 or     false   5.0.0
                       newer, should the driver use the             
                       INFORMATION_SCHEMA to derive                 
                       information used by                          
                       DatabaseMetaData?                            
useJDBCCompliantTimezoneShiftShould the driver use                false   5.0.0
                       JDBC-compliant rules when converting         
                       TIME/TIMESTAMP/DATETIME values'              
                       timezone information for those JDBC          
                       arguments which take a                       
                       java.util.Calendar argument?                 
                       (Notice that this option is                  
                       exclusive of the "useTimezone=true"          
                       configuration option.)                       
useLegacyDatetimeCode  Use code for                         true    5.1.6
                       DATE/TIME/DATETIME/TIMESTAMP                 
                       handling in result sets and                  
                       statements that consistently                 
                       handles timezone conversions from            
                       client to server and back again, or          
                       use the legacy code for these                
                       datatypes that has been in the               
                       driver for backwards-compatibility?          
useOldAliasMetadataBehaviorShould the driver use the legacy     false   5.0.4
                       behavior for "AS" clauses on columns         
                       and tables, and only return aliases          
                       (if any) for                                 
                       ResultSetMetaData.getColumnName() or         
                       ResultSetMetaData.getTableName()             
                       rather than the original                     
                       column/table name? In 5.0.x, the             
                       default value was true.                      
useOldUTF8Behavior     Use the UTF-8 behavior the driver    false   3.1.6
                       did when communicating with 4.0 and          
                       older servers                                
useOnlyServerErrorMessagesDon't prepend 'standard' SQLState    true    3.0.15
                       error messages to error messages             
                       returned by the server.                      
useSSPSCompatibleTimezoneShiftIf migrating from an environment     false   5.0.5
                       that was using server-side prepared          
                       statements, and the configuration            
                       property                                     
                       "useJDBCCompliantTimeZoneShift" set          
                       to "true", use compatible behavior           
                       when not using server-side prepared          
                       statements when sending TIMESTAMP            
                       values to the MySQL server.                  
useServerPrepStmts     Use server-side prepared statements  false   3.1.0
                       if the server supports them?                 
useSqlStateCodes       Use SQL Standard state codes         true    3.1.3
                       instead of 'legacy' X/Open/SQL               
                       state codes (true/false), default            
                       is 'true'                                    
useStreamLengthsInPrepStmtsHonor stream length parameter in     true    3.0.2
                       PreparedStatement/ResultSet.setXXXStream()        
                       method calls (true/false, defaults           
                       to 'true')?                                  
useTimezone            Convert time/date types between      false   3.0.2
                       client and server timezones                  
                       (true/false, defaults to 'false')?           
useUnbufferedInput     Don't use BufferedInputStream for    true    3.0.11
                       reading data from the server                 
yearIsDateType         Should the JDBC driver treat the     true    3.1.9
                       MySQL type "YEAR" as a                       
                       java.sql.Date, or as a SHORT?                
zeroDateTimeBehavior   What should happen when the driver   exception3.1.4
                       encounters DATETIME values that are          
                       composed entirely of zeros (used by          
                       MySQL to represent invalid dates)?           
                       Valid values are "exception",                
                       "round" and "convertToNull".                 

Connector/J also supports access to MySQL using named pipes on Windows
NT/2000/XP using the NamedPipeSocketFactory as a plugin-socket factory
using the socketFactory property.  If you do not use a namedPipePath
property, the default of '\\.\pipe\MySQL' will be used. If you use the
`NamedPipeSocketFactory', the host name and port number values in the
JDBC url will be ignored. You can enable this feature using:

     socketFactory=com.mysql.jdbc.NamedPipeSocketFactory

Named pipes only work when connecting to a MySQL server on the same
physical machine as the one the JDBC driver is being used on. In simple
performance tests, it appears that named pipe access is between 30%-50%
faster than the standard TCP/IP access. However, this varies per
system, and named pipes are slower than TCP/IP in many Windows
configurations.

You can create your own socket factories by following the example code
in com.mysql.jdbc.NamedPipeSocketFactory, or
com.mysql.jdbc.StandardSocketFactory.


File: manual.info,  Node: connector-j-reference-implementation-notes,  Next: connector-j-reference-type-conversions,  Prev: connector-j-reference-configuration-properties,  Up: connector-j-reference

20.3.4.2 JDBC API Implementation Notes
......................................

MySQL Connector/J passes all of the tests in the publicly available
version of Sun's JDBC compliance test suite. However, in many places
the JDBC specification is vague about how certain functionality should
be implemented, or the specification enables leeway in implementation.

This section gives details on a interface-by-interface level about how
certain implementation decisions may affect how you use MySQL
Connector/J.

   * *Blob*

     Starting with Connector/J version 3.1.0, you can emulate Blobs
     with locators by adding the property 'emulateLocators=true' to
     your JDBC URL. Using this method, the driver will delay loading
     the actual Blob data until you retrieve the other data and then
     use retrieval methods (`getInputStream()', `getBytes()', and so
     forth) on the blob data stream.

     For this to work, you must use a column alias with the value of
     the column to the actual name of the Blob, for example:

          SELECT id, 'data' as blob_data from blobtable

     For this to work, you must also follow these rules:

        * The *Note `SELECT': select. must also reference only one
          table, the table must have a primary key.

        * The *Note `SELECT': select. must alias the original blob
          column name, specified as a string, to an alternate name.

        * The *Note `SELECT': select. must cover all columns that make
          up the primary key.

     The Blob implementation does not allow in-place modification (they
     are copies, as reported by the
     `DatabaseMetaData.locatorsUpdateCopies()' method). Because of
     this, you should use the corresponding
     `PreparedStatement.setBlob()' or `ResultSet.updateBlob()' (in the
     case of updatable result sets) methods to save changes back to the
     database.

   * *CallableStatement*

     Starting with Connector/J 3.1.1, stored procedures are supported
     when connecting to MySQL version 5.0 or newer using the
     CallableStatement interface. Currently, the
     `getParameterMetaData()' method of CallableStatement is not
     supported.

   * *Clob*

     The Clob implementation does not allow in-place modification (they
     are copies, as reported by the
     `DatabaseMetaData.locatorsUpdateCopies()' method). Because of
     this, you should use the `PreparedStatement.setClob()' method to
     save changes back to the database. The JDBC API does not have a
     `ResultSet.updateClob()' method.

   * *Connection*

     Unlike older versions of MM.MySQL the `isClosed()' method does not
     ping the server to determine if it is available. In accordance with
     the JDBC specification, it only returns true if `closed()' has
     been called on the connection. If you need to determine if the
     connection is still valid, you should issue a simple query, such as
     `SELECT 1'. The driver will throw an exception if the connection
     is no longer valid.

   * *DatabaseMetaData*

     Foreign Key information (`getImportedKeys()'/`getExportedKeys()'
     and `getCrossReference()') is only available from InnoDB tables.
     However, the driver uses *Note `SHOW CREATE TABLE':
     show-create-table. to retrieve this information, so when other
     storage engines support foreign keys, the driver will
     transparently support them as well.

   * *PreparedStatement*

     PreparedStatements are implemented by the driver, as MySQL does
     not have a prepared statement feature. Because of this, the driver
     does not implement `getParameterMetaData()' or `getMetaData()' as
     it would require the driver to have a complete SQL parser in the
     client.

     Starting with version 3.1.0 MySQL Connector/J, server-side
     prepared statements and binary-encoded result sets are used when
     the server supports them.

     Take care when using a server-side prepared statement with *large*
     parameters that are set using `setBinaryStream()',
     `setAsciiStream()', `setUnicodeStream()', `setBlob()', or
     `setClob()'. To re-execute the statement with any large parameter
     changed to a nonlarge parameter, call `clearParameters()' and set
     all parameters again. The reason for this is as follows:

        * During both server-side prepared statements and client-side
          emulation, large data is exchanged only when
          `PreparedStatement.execute()' is called.

        * Once that has been done, the stream used to read the data on
          the client side is closed (as per the JDBC spec), and cannot
          be read from again.

        * If a parameter changes from large to nonlarge, the driver
          must reset the server-side state of the prepared statement to
          allow the parameter that is being changed to take the place
          of the prior large value. This removes all of the large data
          that has already been sent to the server, thus requiring the
          data to be re-sent, using the `setBinaryStream()',
          `setAsciiStream()', `setUnicodeStream()', `setBlob()' or
          `setClob()' method.

     Consequently, to change the type of a parameter to a nonlarge one,
     you must call `clearParameters()' and set all parameters of the
     prepared statement again before it can be re-executed.

   * *ResultSet*

     By default, ResultSets are completely retrieved and stored in
     memory. In most cases this is the most efficient way to operate,
     and due to the design of the MySQL network protocol is easier to
     implement. If you are working with ResultSets that have a large
     number of rows or large values, and can not allocate heap space in
     your JVM for the memory required, you can tell the driver to
     stream the results back one row at a time.

     To enable this functionality, you need to create a Statement
     instance in the following manner:

          stmt = conn.createStatement(java.sql.ResultSet.TYPE_FORWARD_ONLY,
                        java.sql.ResultSet.CONCUR_READ_ONLY);
          stmt.setFetchSize(Integer.MIN_VALUE);

     The combination of a forward-only, read-only result set, with a
     fetch size of `Integer.MIN_VALUE' serves as a signal to the driver
     to stream result sets row-by-row. After this any result sets
     created with the statement will be retrieved row-by-row.

     There are some caveats with this approach. You will have to read
     all of the rows in the result set (or close it) before you can
     issue any other queries on the connection, or an exception will be
     thrown.

     The earliest the locks these statements hold can be released
     (whether they be `MyISAM' table-level locks or row-level locks in
     some other storage engine such as `InnoDB') is when the statement
     completes.

     If the statement is within scope of a transaction, then locks are
     released when the transaction completes (which implies that the
     statement needs to complete first). As with most other databases,
     statements are not complete until all the results pending on the
     statement are read or the active result set for the statement is
     closed.

     Therefore, if using streaming results, process them as quickly as
     possible if you want to maintain concurrent access to the tables
     referenced by the statement producing the result set.

   * *ResultSetMetaData*

     The `isAutoIncrement()' method only works when using MySQL servers
     4.0 and newer.

   * *Statement*

     When using versions of the JDBC driver earlier than 3.2.1, and
     connected to server versions earlier than 5.0.3, the
     `setFetchSize()' method has no effect, other than to toggle result
     set streaming as described above.

     Connector/J 5.0.0 and later include support for both
     `Statement.cancel()' and `Statement.setQueryTimeout()'. Both
     require MySQL 5.0.0 or newer server, and require a separate
     connection to issue the *Note `KILL QUERY': kill.  statement. In
     the case of `setQueryTimeout()', the implementation creates an
     additional thread to handle the timeout functionality.

     *Note*:

     Failures to cancel the statement for `setQueryTimeout()' may
     manifest themselves as `RuntimeException' rather than failing
     silently, as there is currently no way to unblock the thread that
     is executing the query being cancelled due to timeout expiration
     and have it throw the exception instead.

     MySQL does not support SQL cursors, and the JDBC driver doesn't
     emulate them, so "setCursorName()" has no effect.

     Connector/J 5.1.3 and later include two additional methods:

        * `setLocalInfileInputStream()' sets an `InputStream' instance
          that will be used to send data to the MySQL server for a
          *Note `LOAD DATA LOCAL INFILE': load-data. statement rather
          than a `FileInputStream' or `URLInputStream' that represents
          the path given as an argument to the statement.

          This stream will be read to completion upon execution of a
          *Note `LOAD DATA LOCAL INFILE': load-data. statement, and
          will automatically be closed by the driver, so it needs to be
          reset before each call to `execute*()' that would cause the
          MySQL server to request data to fulfill the request for *Note
          `LOAD DATA LOCAL INFILE': load-data.

          If this value is set to `NULL', the driver will revert to
          using a `FileInputStream' or `URLInputStream' as required.

        * `getLocalInfileInputStream()' returns the `InputStream'
          instance that will be used to send data in response to a
          *Note `LOAD DATA LOCAL INFILE': load-data. statement.

          This method returns `NULL' if no such stream has been set
          using `setLocalInfileInputStream()'.


File: manual.info,  Node: connector-j-reference-type-conversions,  Next: connector-j-reference-charsets,  Prev: connector-j-reference-implementation-notes,  Up: connector-j-reference

20.3.4.3 Java, JDBC and MySQL Types
...................................

MySQL Connector/J is flexible in the way it handles conversions between
MySQL data types and Java data types.

In general, any MySQL data type can be converted to a java.lang.String,
and any numeric type can be converted to any of the Java numeric types,
although round-off, overflow, or loss of precision may occur.

Starting with Connector/J 3.1.0, the JDBC driver will issue warnings or
throw DataTruncation exceptions as is required by the JDBC
specification unless the connection was configured not to do so by
using the property jdbcCompliantTruncation and setting it to `false'.

The conversions that are always guaranteed to work are listed in the
following table:

Connection Properties - Miscellaneous

These MySQL Data Types               Can always be converted to these
                                     Java types
`CHAR, VARCHAR, BLOB, TEXT, ENUM,    `java.lang.String,
and SET'                             java.io.InputStream, java.io.Reader,
                                     java.sql.Blob, java.sql.Clob'
`FLOAT, REAL, DOUBLE PRECISION,      `java.lang.String, java.lang.Short,
NUMERIC, DECIMAL, TINYINT,           java.lang.Integer, java.lang.Long,
SMALLINT, MEDIUMINT, INTEGER,        java.lang.Double,
BIGINT'                              java.math.BigDecimal'
`DATE, TIME, DATETIME, TIMESTAMP'    `java.lang.String, java.sql.Date,
                                     java.sql.Timestamp'

*Note*:

Round-off, overflow or loss of precision may occur if you choose a Java
numeric data type that has less precision or capacity than the MySQL
data type you are converting to/from.

The ResultSet.getObject() method uses the type conversions between
MySQL and Java types, following the JDBC specification where
appropriate. The value returned by
ResultSetMetaData.GetColumnClassName() is also shown below. For more
information on the `java.sql.Types' classes see Java 2 Platform Types
(http://java.sun.com/j2se/1.4.2/docs/api/java/sql/Types.html).

MySQL Types to Java Types for ResultSet.getObject()

MySQL Type Name    Return value of    Returned as Java Class
                   `GetColumnClassName'
BIT(1) (new in     BIT                java.lang.Boolean
MySQL-5.0)                            
BIT( > 1) (new in  BIT                byte[]
MySQL-5.0)                            
TINYINT            TINYINT            java.lang.Boolean if the
                                      configuration property
                                      `tinyInt1isBit' is set to `true'
                                      (the default) and the storage size
                                      is 1, or java.lang.Integer if not.
BOOL, BOOLEAN      TINYINT            See TINYINT, above as these are
                                      aliases for TINYINT(1), currently.
SMALLINT[(M)]      SMALLINT           java.lang.Integer (regardless if
[UNSIGNED]         [UNSIGNED]         UNSIGNED or not)
MEDIUMINT[(M)]     MEDIUMINT          java.lang.Integer, if UNSIGNED
[UNSIGNED]         [UNSIGNED]         java.lang.Long (C/J 3.1 and
                                      earlier), or java.lang.Integer for
                                      C/J 5.0 and later
INT,INTEGER[(M)]   INTEGER [UNSIGNED] java.lang.Integer, if UNSIGNED
[UNSIGNED]                            java.lang.Long
BIGINT[(M)]        BIGINT [UNSIGNED]  java.lang.Long, if UNSIGNED
[UNSIGNED]                            java.math.BigInteger
FLOAT[(M,D)]       FLOAT              java.lang.Float
DOUBLE[(M,B)]      DOUBLE             java.lang.Double
DECIMAL[(M[,D])]   DECIMAL            java.math.BigDecimal
DATE               DATE               java.sql.Date
DATETIME           DATETIME           java.sql.Timestamp
TIMESTAMP[(M)]     TIMESTAMP          java.sql.Timestamp
TIME               TIME               java.sql.Time
YEAR[(2|4)]        YEAR               If `yearIsDateType' configuration
                                      property is set to false, then the
                                      returned object type is
                                      java.sql.Short. If set to true (the
                                      default) then an object of type
                                      java.sql.Date (with the date set to
                                      January 1st, at midnight).
CHAR(M)            CHAR               java.lang.String (unless the
                                      character set for the column is
                                      BINARY, then byte[] is returned.
VARCHAR(M)         VARCHAR            java.lang.String (unless the
[BINARY]                              character set for the column is
                                      BINARY, then byte[] is returned.
BINARY(M)          BINARY             byte[]
VARBINARY(M)       VARBINARY          byte[]
TINYBLOB           TINYBLOB           byte[]
TINYTEXT           VARCHAR            java.lang.String
BLOB               BLOB               byte[]
TEXT               VARCHAR            java.lang.String
MEDIUMBLOB         MEDIUMBLOB         byte[]
MEDIUMTEXT         VARCHAR            java.lang.String
LONGBLOB           LONGBLOB           byte[]
LONGTEXT           VARCHAR            java.lang.String
ENUM('value1','value2',...)CHAR               java.lang.String
SET('value1','value2',...)CHAR               java.lang.String


File: manual.info,  Node: connector-j-reference-charsets,  Next: connector-j-reference-using-ssl,  Prev: connector-j-reference-type-conversions,  Up: connector-j-reference

20.3.4.4 Using Character Sets and Unicode
.........................................

All strings sent from the JDBC driver to the server are converted
automatically from native Java Unicode form to the client character
encoding, including all queries sent using `Statement.execute()',
`Statement.executeUpdate()', `Statement.executeQuery()' as well as all

PreparedStatement

and

CallableStatement

parameters with the exclusion of parameters set using `setBytes()',
`setBinaryStream()', `setAsciiStream()', `setUnicodeStream()' and
`setBlob()'.

Prior to MySQL Server 4.1, Connector/J supported a single character
encoding per connection, which could either be automatically detected
from the server configuration, or could be configured by the user
through the useUnicode and characterEncoding properties.

Starting with MySQL Server 4.1, Connector/J supports a single character
encoding between client and server, and any number of character
encodings for data returned by the server to the client in ResultSets.

The character encoding between client and server is automatically
detected upon connection. The encoding used by the driver is specified
on the server using the `character_set' system variable for server
versions older than 4.1.0 and `character_set_server' for server
versions 4.1.0 and newer. For more information, see *Note
charset-server::.

To override the automatically detected encoding on the client side, use
the characterEncoding property in the URL used to connect to the server.

When specifying character encodings on the client side, Java-style
names should be used. The following table lists Java-style names for
MySQL character sets:

MySQL to Java Encoding Name Translations

MySQL Character Set Name             Java-Style Character Encoding Name
ascii                                US-ASCII
big5                                 Big5
gbk                                  GBK
sjis                                 SJIS (or Cp932 or MS932 for MySQL
                                     Server < 4.1.11)
cp932                                Cp932 or MS932 (MySQL Server >
                                     4.1.11)
gb2312                               EUC_CN
ujis                                 EUC_JP
euckr                                EUC_KR
latin1                               Cp1252
latin2                               ISO8859_2
greek                                ISO8859_7
hebrew                               ISO8859_8
cp866                                Cp866
tis620                               TIS620
cp1250                               Cp1250
cp1251                               Cp1251
cp1257                               Cp1257
macroman                             MacRoman
macce                                MacCentralEurope
utf8                                 UTF-8
ucs2                                 UnicodeBig

*Warning*:

Do not issue the query 'set names' with Connector/J, as the driver will
not detect that the character set has changed, and will continue to use
the character set detected during the initial connection setup.

To allow multiple character sets to be sent from the client, the UTF-8
encoding should be used, either by configuring `utf8' as the default
server character set, or by configuring the JDBC driver to use UTF-8
through the characterEncoding property.


File: manual.info,  Node: connector-j-reference-using-ssl,  Next: connector-j-reference-replication-connection,  Prev: connector-j-reference-charsets,  Up: connector-j-reference

20.3.4.5 Connecting Securely Using SSL
......................................

SSL in MySQL Connector/J encrypts all data (other than the initial
handshake) between the JDBC driver and the server. The performance
penalty for enabling SSL is an increase in query processing time
between 35% and 50%, depending on the size of the query, and the amount
of data it returns.

For SSL Support to work, you must have the following:

   * A JDK that includes JSSE (Java Secure Sockets Extension), like
     JDK-1.4.1 or newer. SSL does not currently work with a JDK that
     you can add JSSE to, like JDK-1.2.x or JDK-1.3.x due to the
     following JSSE bug:
     `http://developer.java.sun.com/developer/bugParade/bugs/4273544.html'

   * A MySQL server that supports SSL and has been compiled and
     configured to do so, which is MySQL-4.0.4 or later, see *Note
     secure-connections::, for more information.

   * A client certificate (covered later in this section)

The system works through two Java truststore files, one file contains
the certificate information for the server (`truststore' in the
examples below). The other file contains the certificate for the client
(`keystore' in the examples below). All Java truststore files are
password protected by supplying a suitable password to the `keytool'
when you create the files. You need the file names and associated
passwords to create an SSL connection.

You will first need to import the MySQL server CA Certificate into a
Java truststore. A sample MySQL server CA Certificate is located in the
`SSL' subdirectory of the MySQL source distribution. This is what SSL
will use to determine if you are communicating with a secure MySQL
server.  Alternatively, use the CA Certificate that you have generated
or been provided with by your SSL provider.

To use Java's `keytool' to create a truststore in the current directory
, and import the server's CA certificate (`cacert.pem'), you can do the
following (assuming that `keytool' is in your path. The `keytool'
should be located in the `bin' subdirectory of your JDK or JRE):

     shell> keytool -import -alias mysqlServerCACert \
                                       -file cacert.pem -keystore truststore

You will need to enter the password when prompted for the keystore
file. Interaction with `keytool' will look like this:

     Enter keystore password:  *********
     Owner: EMAILADDRESS=walrus@example.com, CN=Walrus,
            O=MySQL AB, L=Orenburg, ST=Some-State, C=RU
     Issuer: EMAILADDRESS=walrus@example.com, CN=Walrus,
            O=MySQL AB, L=Orenburg, ST=Some-State, C=RU
     Serial number: 0
     Valid from:
        Fri Aug 02 16:55:53 CDT 2002 until: Sat Aug 02 16:55:53 CDT 2003
     Certificate fingerprints:
         MD5:  61:91:A0:F2:03:07:61:7A:81:38:66:DA:19:C4:8D:AB
         SHA1: 25:77:41:05:D5:AD:99:8C:14:8C:CA:68:9C:2F:B8:89:C3:34:4D:6C
     Trust this certificate? [no]:  yes
     Certificate was added to keystore

You then have two options, you can either import the client certificate
that matches the CA certificate you just imported, or you can create a
new client certificate.

To import an existing certificate, the certificate should be in DER
format. You can use `openssl' to convert an existing certificate into
the new format. For example:

     shell> openssl x509 -outform DER -in client-cert.pem -out client.cert

You now need to import the converted certificate into your keystore
using `keytool':

     shell> keytool -import -file client.cert -keystore keystore -alias mysqlClientCertificate

To generate your own client certificate, use `keytool' to create a
suitable certificate and add it to the `keystore' file:

      shell> keytool -genkey -keyalg rsa \
          -alias mysqlClientCertificate -keystore keystore

Keytool will prompt you for the following information, and create a
keystore named `keystore' in the current directory.

You should respond with information that is appropriate for your
situation:

     Enter keystore password:  *********
     What is your first and last name?
       [Unknown]:  Matthews
     What is the name of your organizational unit?
       [Unknown]:  Software Development
     What is the name of your organization?
       [Unknown]:  MySQL AB
     What is the name of your City or Locality?
       [Unknown]:  Flossmoor
     What is the name of your State or Province?
       [Unknown]:  IL
     What is the two-letter country code for this unit?
       [Unknown]:  US
     Is <CN=Matthews, OU=Software Development, O=MySQL AB,
      L=Flossmoor, ST=IL, C=US> correct?
       [no]:  y

     Enter key password for <mysqlClientCertificate>
             (RETURN if same as keystore password):

Finally, to get JSSE to use the keystore and truststore that you have
generated, you need to set the following system properties when you
start your JVM, replacing path_to_keystore_file with the full path to
the keystore file you created, path_to_truststore_file with the path to
the truststore file you created, and using the appropriate password
values for each property. You can do this either on the command line:

     -Djavax.net.ssl.keyStore=path_to_keystore_file
     -Djavax.net.ssl.keyStorePassword=password
     -Djavax.net.ssl.trustStore=path_to_truststore_file
     -Djavax.net.ssl.trustStorePassword=password

Or you can set the values directly within the application:

      System.setProperty("javax.net.ssl.keyStore","path_to_keystore_file");
     System.setProperty("javax.net.ssl.keyStorePassword","password");
     System.setProperty("javax.net.ssl.trustStore","path_to_truststore_file");
     System.setProperty("javax.net.ssl.trustStorePassword","password");

You will also need to set useSSL to `true' in your connection
parameters for MySQL Connector/J, either by adding `useSSL=true' to
your URL, or by setting the property useSSL to `true' in the
java.util.Properties instance you pass to
`DriverManager.getConnection()'.

You can test that SSL is working by turning on JSSE debugging (as
detailed below), and look for the following key events:

     ...
     *** ClientHello, v3.1
     RandomCookie:  GMT: 1018531834 bytes = { 199, 148, 180, 215, 74, 12, »
       54, 244, 0, 168, 55, 103, 215, 64, 16, 138, 225, 190, 132, 153, 2, »
       217, 219, 239, 202, 19, 121, 78 }
     Session ID:  {}
     Cipher Suites:  { 0, 5, 0, 4, 0, 9, 0, 10, 0, 18, 0, 19, 0, 3, 0, 17 }
     Compression Methods:  { 0 }
     ***
     [write] MD5 and SHA1 hashes:  len = 59
     0000: 01 00 00 37 03 01 3D B6 90 FA C7 94 B4 D7 4A 0C  ...7..=.......J.
     0010: 36 F4 00 A8 37 67 D7 40 10 8A E1 BE 84 99 02 D9  6...7g.@........
     0020: DB EF CA 13 79 4E 00 00 10 00 05 00 04 00 09 00  ....yN..........
     0030: 0A 00 12 00 13 00 03 00 11 01 00                 ...........
     main, WRITE:  SSL v3.1 Handshake, length = 59
     main, READ:  SSL v3.1 Handshake, length = 74
     *** ServerHello, v3.1
     RandomCookie:  GMT: 1018577560 bytes = { 116, 50, 4, 103, 25, 100, 58, »
        202, 79, 185, 178, 100, 215, 66, 254, 21, 83, 187, 190, 42, 170, 3, »
        132, 110, 82, 148, 160, 92 }
     Session ID:  {163, 227, 84, 53, 81, 127, 252, 254, 178, 179, 68, 63, »
        182, 158, 30, 11, 150, 79, 170, 76, 255, 92, 15, 226, 24, 17, 177, »
        219, 158, 177, 187, 143}
     Cipher Suite:  { 0, 5 }
     Compression Method: 0
     ***
     %% Created:  [Session-1, SSL_RSA_WITH_RC4_128_SHA]
     ** SSL_RSA_WITH_RC4_128_SHA
     [read] MD5 and SHA1 hashes:  len = 74
     0000: 02 00 00 46 03 01 3D B6 43 98 74 32 04 67 19 64  ...F..=.C.t2.g.d
     0010: 3A CA 4F B9 B2 64 D7 42 FE 15 53 BB BE 2A AA 03  :.O..d.B..S..*..
     0020: 84 6E 52 94 A0 5C 20 A3 E3 54 35 51 7F FC FE B2  .nR..\ ..T5Q....
     0030: B3 44 3F B6 9E 1E 0B 96 4F AA 4C FF 5C 0F E2 18  .D?.....O.L.\...
     0040: 11 B1 DB 9E B1 BB 8F 00 05 00                    ..........
     main, READ:  SSL v3.1 Handshake, length = 1712
     ...

JSSE provides debugging (to STDOUT) when you set the following system
property: `-Djavax.net.debug=all' This will tell you what keystores and
truststores are being used, as well as what is going on during the SSL
handshake and certificate exchange. It will be helpful when trying to
determine what is not working when trying to get an SSL connection to
happen.


File: manual.info,  Node: connector-j-reference-replication-connection,  Next: connector-j-reference-error-sqlstates,  Prev: connector-j-reference-using-ssl,  Up: connector-j-reference

20.3.4.6 Using Master/Slave Replication with ReplicationConnection
..................................................................

Starting with Connector/J 3.1.7, we've made available a variant of the
driver that will automatically send queries to a read/write master, or
a failover or round-robin loadbalanced set of slaves based on the state
of `Connection.getReadOnly()' .

An application signals that it wants a transaction to be read-only by
calling `Connection.setReadOnly(true)', this replication-aware
connection will use one of the slave connections, which are
load-balanced per-vm using a round-robin scheme (a given connection is
sticky to a slave unless that slave is removed from service). If you
have a write transaction, or if you have a read that is time-sensitive
(remember, replication in MySQL is asynchronous), set the connection to
be not read-only, by calling `Connection.setReadOnly(false)' and the
driver will ensure that further calls are sent to the master MySQL
server. The driver takes care of propagating the current state of
autocommit, isolation level, and catalog between all of the connections
that it uses to accomplish this load balancing functionality.

To enable this functionality, use the "
`com.mysql.jdbc.ReplicationDriver' " class when configuring your
application server's connection pool or when creating an instance of a
JDBC driver for your standalone application. Because it accepts the
same URL format as the standard MySQL JDBC driver, `ReplicationDriver'
does not currently work with `java.sql.DriverManager' -based connection
creation unless it is the only MySQL JDBC driver registered with the
`DriverManager' .

Here is a short, simple example of how ReplicationDriver might be used
in a standalone application.

     import java.sql.Connection;
     import java.sql.ResultSet;
     import java.util.Properties;

     import com.mysql.jdbc.ReplicationDriver;

     public class ReplicationDriverDemo {

       public static void main(String[] args) throws Exception {
         ReplicationDriver driver = new ReplicationDriver();

         Properties props = new Properties();

         // We want this for failover on the slaves
         props.put("autoReconnect", "true");

         // We want to load balance between the slaves
         props.put("roundRobinLoadBalance", "true");

         props.put("user", "foo");
         props.put("password", "bar");

         //
         // Looks like a normal MySQL JDBC url, with a
         // comma-separated list of hosts, the first
         // being the 'master', the rest being any number
         // of slaves that the driver will load balance against
         //

         Connection conn =
             driver.connect("jdbc:mysql:replication://master,slave1,slave2,slave3/test",
                 props);

         //
         // Perform read/write work on the master
         // by setting the read-only flag to "false"
         //

         conn.setReadOnly(false);
         conn.setAutoCommit(false);
         conn.createStatement().executeUpdate("UPDATE some_table ....");
         conn.commit();

         //
         // Now, do a query from a slave, the driver automatically picks one
         // from the list
         //

         conn.setReadOnly(true);

         ResultSet rs =
           conn.createStatement().executeQuery("SELECT a,b FROM alt_table");

          .......
       }
     }

Consider investigating the Load Balancing JDBC Pool (lbpol) tool, which
provides a wrapper around the standard JDBC driver and enables you to
use DB connection pools that includes checks for system failures and
uneven load distribution. For more information, see Load Balancing JDBC
Pool (lbpool) (http://code.tailrank.com/lbpool).


File: manual.info,  Node: connector-j-reference-error-sqlstates,  Prev: connector-j-reference-replication-connection,  Up: connector-j-reference

20.3.4.7 Mapping MySQL Error Numbers to SQLStates
.................................................

The table below provides a mapping of the MySQL Error Numbers to `SQL
States'

*Mapping of MySQL Error Numbers to SQLStates*

MySQL Error    MySQL Error Name              Legacy         SQL Standard
Number                                       (X/Open)       SQLState
                                             SQLState       
1022           ER_DUP_KEY                    S1000          23000
1037           ER_OUTOFMEMORY                S1001          HY001
1038           ER_OUT_OF_SORTMEMORY          S1001          HY001
1040           ER_CON_COUNT_ERROR            08004          08004
1042           ER_BAD_HOST_ERROR             08004          08S01
1043           ER_HANDSHAKE_ERROR            08004          08S01
1044           ER_DBACCESS_DENIED_ERROR      S1000          42000
1045           ER_ACCESS_DENIED_ERROR        28000          28000
1047           ER_UNKNOWN_COM_ERROR          08S01          HY000
1050           ER_TABLE_EXISTS_ERROR         S1000          42S01
1051           ER_BAD_TABLE_ERROR            42S02          42S02
1052           ER_NON_UNIQ_ERROR             S1000          23000
1053           ER_SERVER_SHUTDOWN            S1000          08S01
1054           ER_BAD_FIELD_ERROR            S0022          42S22
1055           ER_WRONG_FIELD_WITH_GROUP     S1009          42000
1056           ER_WRONG_GROUP_FIELD          S1009          42000
1057           ER_WRONG_SUM_SELECT           S1009          42000
1058           ER_WRONG_VALUE_COUNT          21S01          21S01
1059           ER_TOO_LONG_IDENT             S1009          42000
1060           ER_DUP_FIELDNAME              S1009          42S21
1061           ER_DUP_KEYNAME                S1009          42000
1062           ER_DUP_ENTRY                  S1009          23000
1063           ER_WRONG_FIELD_SPEC           S1009          42000
1064           ER_PARSE_ERROR                42000          42000
1065           ER_EMPTY_QUERY                42000          42000
1066           ER_NONUNIQ_TABLE              S1009          42000
1067           ER_INVALID_DEFAULT            S1009          42000
1068           ER_MULTIPLE_PRI_KEY           S1009          42000
1069           ER_TOO_MANY_KEYS              S1009          42000
1070           ER_TOO_MANY_KEY_PARTS         S1009          42000
1071           ER_TOO_LONG_KEY               S1009          42000
1072           ER_KEY_COLUMN_DOES_NOT_EXITS  S1009          42000
1073           ER_BLOB_USED_AS_KEY           S1009          42000
1074           ER_TOO_BIG_FIELDLENGTH        S1009          42000
1075           ER_WRONG_AUTO_KEY             S1009          42000
1080           ER_FORCING_CLOSE              S1000          08S01
1081           ER_IPSOCK_ERROR               08S01          08S01
1082           ER_NO_SUCH_INDEX              S1009          42S12
1083           ER_WRONG_FIELD_TERMINATORS    S1009          42000
1084           ER_BLOBS_AND_NO_TERMINATED    S1009          42000
1090           ER_CANT_REMOVE_ALL_FIELDS     S1000          42000
1091           ER_CANT_DROP_FIELD_OR_KEY     S1000          42000
1101           ER_BLOB_CANT_HAVE_DEFAULT     S1000          42000
1102           ER_WRONG_DB_NAME              S1000          42000
1103           ER_WRONG_TABLE_NAME           S1000          42000
1104           ER_TOO_BIG_SELECT             S1000          42000
1106           ER_UNKNOWN_PROCEDURE          S1000          42000
1107           ER_WRONG_PARAMCOUNT_TO_PROCEDURES1000          42000
1109           ER_UNKNOWN_TABLE              S1000          42S02
1110           ER_FIELD_SPECIFIED_TWICE      S1000          42000
1112           ER_UNSUPPORTED_EXTENSION      S1000          42000
1113           ER_TABLE_MUST_HAVE_COLUMNS    S1000          42000
1115           ER_UNKNOWN_CHARACTER_SET      S1000          42000
1118           ER_TOO_BIG_ROWSIZE            S1000          42000
1120           ER_WRONG_OUTER_JOIN           S1000          42000
1121           ER_NULL_COLUMN_IN_INDEX       S1000          42000
1129           ER_HOST_IS_BLOCKED            08004          HY000
1130           ER_HOST_NOT_PRIVILEGED        08004          HY000
1131           ER_PASSWORD_ANONYMOUS_USER    S1000          42000
1132           ER_PASSWORD_NOT_ALLOWED       S1000          42000
1133           ER_PASSWORD_NO_MATCH          S1000          42000
1136           ER_WRONG_VALUE_COUNT_ON_ROW   S1000          21S01
1138           ER_INVALID_USE_OF_NULL        S1000          42000
1139           ER_REGEXP_ERROR               S1000          42000
1140           ER_MIX_OF_GROUP_FUNC_AND_FIELDSS1000          42000
1141           ER_NONEXISTING_GRANT          S1000          42000
1142           ER_TABLEACCESS_DENIED_ERROR   S1000          42000
1143           ER_COLUMNACCESS_DENIED_ERROR  S1000          42000
1144           ER_ILLEGAL_GRANT_FOR_TABLE    S1000          42000
1145           ER_GRANT_WRONG_HOST_OR_USER   S1000          42000
1146           ER_NO_SUCH_TABLE              S1000          42S02
1147           ER_NONEXISTING_TABLE_GRANT    S1000          42000
1148           ER_NOT_ALLOWED_COMMAND        S1000          42000
1149           ER_SYNTAX_ERROR               S1000          42000
1152           ER_ABORTING_CONNECTION        S1000          08S01
1153           ER_NET_PACKET_TOO_LARGE       S1000          08S01
1154           ER_NET_READ_ERROR_FROM_PIPE   S1000          08S01
1155           ER_NET_FCNTL_ERROR            S1000          08S01
1156           ER_NET_PACKETS_OUT_OF_ORDER   S1000          08S01
1157           ER_NET_UNCOMPRESS_ERROR       S1000          08S01
1158           ER_NET_READ_ERROR             S1000          08S01
1159           ER_NET_READ_INTERRUPTED       S1000          08S01
1160           ER_NET_ERROR_ON_WRITE         S1000          08S01
1161           ER_NET_WRITE_INTERRUPTED      S1000          08S01
1162           ER_TOO_LONG_STRING            S1000          42000
1163           ER_TABLE_CANT_HANDLE_BLOB     S1000          42000
1164           ER_TABLE_CANT_HANDLE_AUTO_INCREMENTS1000          42000
1166           ER_WRONG_COLUMN_NAME          S1000          42000
1167           ER_WRONG_KEY_COLUMN           S1000          42000
1169           ER_DUP_UNIQUE                 S1000          23000
1170           ER_BLOB_KEY_WITHOUT_LENGTH    S1000          42000
1171           ER_PRIMARY_CANT_HAVE_NULL     S1000          42000
1172           ER_TOO_MANY_ROWS              S1000          42000
1173           ER_REQUIRES_PRIMARY_KEY       S1000          42000
1177           ER_CHECK_NO_SUCH_TABLE        S1000          42000
1178           ER_CHECK_NOT_IMPLEMENTED      S1000          42000
1179           ER_CANT_DO_THIS_DURING_AN_TRANSACTIONS1000          25000
1184           ER_NEW_ABORTING_CONNECTION    S1000          08S01
1189           ER_MASTER_NET_READ            S1000          08S01
1190           ER_MASTER_NET_WRITE           S1000          08S01
1203           ER_TOO_MANY_USER_CONNECTIONS  S1000          42000
1205           ER_LOCK_WAIT_TIMEOUT          41000          41000
1207           ER_READ_ONLY_TRANSACTION      S1000          25000
1211           ER_NO_PERMISSION_TO_CREATE_USERS1000          42000
1213           ER_LOCK_DEADLOCK              41000          40001
1216           ER_NO_REFERENCED_ROW          S1000          23000
1217           ER_ROW_IS_REFERENCED          S1000          23000
1218           ER_CONNECT_TO_MASTER          S1000          08S01
1222           ER_WRONG_NUMBER_OF_COLUMNS_IN_SELECTS1000          21000
1226           ER_USER_LIMIT_REACHED         S1000          42000
1230           ER_NO_DEFAULT                 S1000          42000
1231           ER_WRONG_VALUE_FOR_VAR        S1000          42000
1232           ER_WRONG_TYPE_FOR_VAR         S1000          42000
1234           ER_CANT_USE_OPTION_HERE       S1000          42000
1235           ER_NOT_SUPPORTED_YET          S1000          42000
1239           ER_WRONG_FK_DEF               S1000          42000
1241           ER_OPERAND_COLUMNS            S1000          21000
1242           ER_SUBQUERY_NO_1_ROW          S1000          21000
1247           ER_ILLEGAL_REFERENCE          S1000          42S22
1248           ER_DERIVED_MUST_HAVE_ALIAS    S1000          42000
1249           ER_SELECT_REDUCED             S1000          01000
1250           ER_TABLENAME_NOT_ALLOWED_HERE S1000          42000
1251           ER_NOT_SUPPORTED_AUTH_MODE    S1000          08004
1252           ER_SPATIAL_CANT_HAVE_NULL     S1000          42000
1253           ER_COLLATION_CHARSET_MISMATCH S1000          42000
1261           ER_WARN_TOO_FEW_RECORDS       S1000          01000
1262           ER_WARN_TOO_MANY_RECORDS      S1000          01000
1263           ER_WARN_NULL_TO_NOTNULL       S1000          01000
1264           ER_WARN_DATA_OUT_OF_RANGE     S1000          01000
1265           ER_WARN_DATA_TRUNCATED        S1000          01000
1280           ER_WRONG_NAME_FOR_INDEX       S1000          42000
1281           ER_WRONG_NAME_FOR_CATALOG     S1000          42000
1286           ER_UNKNOWN_STORAGE_ENGINE     S1000          42000


File: manual.info,  Node: connector-j-usagenotes,  Next: connector-j-support,  Prev: connector-j-reference,  Up: connector-j

20.3.5 Connector/J Notes and Tips
---------------------------------

* Menu:

* connector-j-usagenotes-basic::  Basic JDBC Concepts
* connector-j-usagenotes-j2ee::  Using Connector/J with J2EE and Other Java Frameworks
* connector-j-usagenotes-troubleshooting::  Connector/J: Common Problems and Solutions


File: manual.info,  Node: connector-j-usagenotes-basic,  Next: connector-j-usagenotes-j2ee,  Prev: connector-j-usagenotes,  Up: connector-j-usagenotes

20.3.5.1 Basic JDBC Concepts
............................

* Menu:

* connector-j-usagenotes-connect-drivermanager::  Connecting to MySQL Using the `DriverManager' Interface
* connector-j-usagenotes-statements::  Using Statements to Execute SQL
* connector-j-usagenotes-statements-callable::  Using `CallableStatements' to Execute Stored Procedures
* connector-j-usagenotes-last-insert-id::  Retrieving `AUTO_INCREMENT' Column Values

This section provides some general JDBC background.


File: manual.info,  Node: connector-j-usagenotes-connect-drivermanager,  Next: connector-j-usagenotes-statements,  Prev: connector-j-usagenotes-basic,  Up: connector-j-usagenotes-basic

20.3.5.2 Connecting to MySQL Using the `DriverManager' Interface
................................................................

When you are using JDBC outside of an application server, the
`DriverManager' class manages the establishment of Connections.

The `DriverManager' needs to be told which JDBC drivers it should try
to make Connections with. The easiest way to do this is to use
`Class.forName()' on the class that implements the `java.sql.Driver'
interface.  With MySQL Connector/J, the name of this class is
`com.mysql.jdbc.Driver'. With this method, you could use an external
configuration file to supply the driver class name and driver
parameters to use when connecting to a database.

The following section of Java code shows how you might register MySQL
Connector/J from the `main()' method of your application. If testing
this code please ensure you read the installation section first at
*Note connector-j-installing::, to make sure you have connector
installed correctly and the `CLASSPATH' set up. Also, ensure that MySQL
is configured to accept external TCP/IP connections.

     import java.sql.Connection;
     import java.sql.DriverManager;
     import java.sql.SQLException;

     // Notice, do not import com.mysql.jdbc.*
     // or you will have problems!

     public class LoadDriver {
         public static void main(String[] args) {
             try {
                 // The newInstance() call is a work around for some
                 // broken Java implementations

                 Class.forName("com.mysql.jdbc.Driver").newInstance();
             } catch (Exception ex) {
                 // handle the error
             }
         }
     }

After the driver has been registered with the `DriverManager', you can
obtain a `Connection' instance that is connected to a particular
database by calling `DriverManager.getConnection()':

If you have not already done so, please review the section *Note
connector-j-usagenotes-connect-drivermanager:: before working with
these examples.

This example shows how you can obtain a `Connection' instance from the
`DriverManager'. There are a few different signatures for the
`getConnection()' method. You should see the API documentation that
comes with your JDK for more specific information on how to use them.

     import java.sql.Connection;
     import java.sql.DriverManager;
     import java.sql.SQLException;

     Connection conn = null;
     ...
     try {
         conn =
            DriverManager.getConnection("jdbc:mysql://localhost/test?" +
                                        "user=monty&password=greatsqldb");

         // Do something with the Connection

        ...
     } catch (SQLException ex) {
         // handle any errors
         System.out.println("SQLException: " + ex.getMessage());
         System.out.println("SQLState: " + ex.getSQLState());
         System.out.println("VendorError: " + ex.getErrorCode());
     }

Once a Connection is established, it can be used to create Statement and
PreparedStatement objects, as well as retrieve metadata about the
database. This is explained in the following sections.


File: manual.info,  Node: connector-j-usagenotes-statements,  Next: connector-j-usagenotes-statements-callable,  Prev: connector-j-usagenotes-connect-drivermanager,  Up: connector-j-usagenotes-basic

20.3.5.3 Using Statements to Execute SQL
........................................

Statement objects allow you to execute basic SQL queries and retrieve
the results through the `ResultSet' class which is described later.

To create a Statement instance, you call the `createStatement()' method
on the `Connection' object you have retrieved using one of the
`DriverManager.getConnection()' or `DataSource.getConnection()' methods
described earlier.

Once you have a Statement instance, you can execute a *Note `SELECT':
select. query by calling the `executeQuery(String)' method with the SQL
you want to use.

To update data in the database, use the `executeUpdate(String SQL)'
method. This method returns the number of rows matched by the update
statement, not the number of rows that were modified.

If you do not know ahead of time whether the SQL statement will be a
*Note `SELECT': select. or an *Note `UPDATE': update./*Note `INSERT':
insert, then you can use the `execute(String SQL)' method. This method
will return true if the SQL query was a *Note `SELECT': select, or
false if it was an *Note `UPDATE': update, *Note `INSERT': insert, or
*Note `DELETE': delete. statement. If the statement was a *Note
`SELECT': select. query, you can retrieve the results by calling the
`getResultSet()' method. If the statement was an *Note `UPDATE': update,
*Note `INSERT': insert, or *Note `DELETE': delete. statement, you can
retrieve the affected rows count by calling `getUpdateCount()' on the
Statement instance.


     import java.sql.Connection;
     import java.sql.DriverManager;
     import java.sql.SQLException;
     import java.sql.Statement;
     import java.sql.ResultSet;

     // assume that conn is an already created JDBC connection (see previous examples)

     Statement stmt = null;
     ResultSet rs = null;

     try {
         stmt = conn.createStatement();
         rs = stmt.executeQuery("SELECT foo FROM bar");

         // or alternatively, if you don't know ahead of time that
         // the query will be a SELECT...

         if (stmt.execute("SELECT foo FROM bar")) {
             rs = stmt.getResultSet();
         }

         // Now do something with the ResultSet ....
     }
     catch (SQLException ex){
         // handle any errors
         System.out.println("SQLException: " + ex.getMessage());
         System.out.println("SQLState: " + ex.getSQLState());
         System.out.println("VendorError: " + ex.getErrorCode());
     }
     finally {
         // it is a good idea to release
         // resources in a finally{} block
         // in reverse-order of their creation
         // if they are no-longer needed

         if (rs != null) {
             try {
                 rs.close();
             } catch (SQLException sqlEx) { } // ignore

             rs = null;
         }

         if (stmt != null) {
             try {
                 stmt.close();
             } catch (SQLException sqlEx) { } // ignore

             stmt = null;
         }
     }


File: manual.info,  Node: connector-j-usagenotes-statements-callable,  Next: connector-j-usagenotes-last-insert-id,  Prev: connector-j-usagenotes-statements,  Up: connector-j-usagenotes-basic

20.3.5.4 Using `CallableStatements' to Execute Stored Procedures
................................................................

Starting with MySQL server version 5.0 when used with Connector/J 3.1.1
or newer, the java.sql.CallableStatement interface is fully implemented
with the exception of the `getParameterMetaData()' method.

For more information on MySQL stored procedures, please refer to
`http://dev.mysql.com/doc/mysql/en/stored-routines.html'.

Connector/J exposes stored procedure functionality through JDBC's
CallableStatement interface.

*Note*:

Current versions of MySQL server do not return enough information for
the JDBC driver to provide result set metadata for callable statements.
This means that when using `CallableStatement', `ResultSetMetaData' may
return `NULL'.

The following example shows a stored procedure that returns the value
of inOutParam incremented by 1, and the string passed in using
inputParam as a ResultSet:

     CREATE PROCEDURE demoSp(IN inputParam VARCHAR(255), \
                                             INOUT inOutParam INT)
     BEGIN
         DECLARE z INT;
         SET z = inOutParam + 1;
         SET inOutParam = z;

         SELECT inputParam;

         SELECT CONCAT('zyxw', inputParam);
     END

To use the `demoSp' procedure with Connector/J, follow these steps:

  1. Prepare the callable statement by using `Connection.prepareCall()'
     .

     Notice that you have to use JDBC escape syntax, and that the
     parentheses surrounding the parameter placeholders are not
     optional:

          import java.sql.CallableStatement;

          ...

              //
              // Prepare a call to the stored procedure 'demoSp'
              // with two parameters
              //
              // Notice the use of JDBC-escape syntax ({call ...})
              //

              CallableStatement cStmt = conn.prepareCall("{call demoSp(?, ?)}");

              cStmt.setString(1, "abcdefg");

     *Note*:

     `Connection.prepareCall()' is an expensive method, due to the
     metadata retrieval that the driver performs to support output
     parameters. For performance reasons, you should try to minimize
     unnecessary calls to `Connection.prepareCall()' by reusing
     CallableStatement instances in your code.

  2. Register the output parameters (if any exist)

     To retrieve the values of output parameters (parameters specified
     as `OUT' or `INOUT' when you created the stored procedure), JDBC
     requires that they be specified before statement execution using
     the various `registerOutputParameter()' methods in the
     CallableStatement interface:

          import java.sql.Types;
          ...
          //
          // Connector/J supports both named and indexed
          // output parameters. You can register output
          // parameters using either method, as well
          // as retrieve output parameters using either
          // method, regardless of what method was
          // used to register them.
          //
          // The following examples show how to use
          // the various methods of registering
          // output parameters (you should of course
          // use only one registration per parameter).
          //

          //
          // Registers the second parameter as output, and
          // uses the type 'INTEGER' for values returned from
          // getObject()
          //

          cStmt.registerOutParameter(2, Types.INTEGER);

          //
          // Registers the named parameter 'inOutParam', and
          // uses the type 'INTEGER' for values returned from
          // getObject()
          //

          cStmt.registerOutParameter("inOutParam", Types.INTEGER);
          ...

  3. Set the input parameters (if any exist)

     Input and in/out parameters are set as for PreparedStatement
     objects. However, CallableStatement also supports setting
     parameters by name:

          ...

              //
              // Set a parameter by index
              //

              cStmt.setString(1, "abcdefg");

              //
              // Alternatively, set a parameter using
              // the parameter name
              //

              cStmt.setString("inputParameter", "abcdefg");

              //
              // Set the 'in/out' parameter using an index
              //

              cStmt.setInt(2, 1);

              //
              // Alternatively, set the 'in/out' parameter
              // by name
              //

              cStmt.setInt("inOutParam", 1);

          ...

  4. Execute the CallableStatement, and retrieve any result sets or
     output parameters.

     Although CallableStatement supports calling any of the Statement
     execute methods (`executeUpdate()', `executeQuery()' or
     `execute()'), the most flexible method to call is `execute()', as
     you do not need to know ahead of time if the stored procedure
     returns result sets:

          ...

              boolean hadResults = cStmt.execute();

              //
              // Process all returned result sets
              //

              while (hadResults) {
                  ResultSet rs = cStmt.getResultSet();

                  // process result set
                  ...

                  hadResults = cStmt.getMoreResults();
              }

              //
              // Retrieve output parameters
              //
              // Connector/J supports both index-based and
              // name-based retrieval
              //

              int outputValue = cStmt.getInt(2); // index-based

              outputValue = cStmt.getInt("inOutParam"); // name-based

          ...


File: manual.info,  Node: connector-j-usagenotes-last-insert-id,  Prev: connector-j-usagenotes-statements-callable,  Up: connector-j-usagenotes-basic

20.3.5.5 Retrieving `AUTO_INCREMENT' Column Values
..................................................

Before version 3.0 of the JDBC API, there was no standard way of
retrieving key values from databases that supported auto increment or
identity columns. With older JDBC drivers for MySQL, you could always
use a MySQL-specific method on the Statement interface, or issue the
query `SELECT LAST_INSERT_ID()' after issuing an *Note `INSERT':
insert. to a table that had an `AUTO_INCREMENT' key. Using the
MySQL-specific method call isn't portable, and issuing a *Note
`SELECT': select. to get the `AUTO_INCREMENT' key's value requires
another round-trip to the database, which isn't as efficient as
possible. The following code snippets demonstrate the three different
ways to retrieve `AUTO_INCREMENT' values. First, we demonstrate the use
of the new JDBC-3.0 method `getGeneratedKeys()' which is now the
preferred method to use if you need to retrieve `AUTO_INCREMENT' keys
and have access to JDBC-3.0. The second example shows how you can
retrieve the same value using a standard `SELECT LAST_INSERT_ID()'
query. The final example shows how updatable result sets can retrieve
the `AUTO_INCREMENT' value when using the `insertRow()' method.

        Statement stmt = null;
        ResultSet rs = null;

        try {

         //
         // Create a Statement instance that we can use for
         // 'normal' result sets assuming you have a
         // Connection 'conn' to a MySQL database already
         // available

         stmt = conn.createStatement(java.sql.ResultSet.TYPE_FORWARD_ONLY,
                                     java.sql.ResultSet.CONCUR_UPDATABLE);

         //
         // Issue the DDL queries for the table for this example
         //

         stmt.executeUpdate("DROP TABLE IF EXISTS autoIncTutorial");
         stmt.executeUpdate(
                 "CREATE TABLE autoIncTutorial ("
                 + "priKey INT NOT NULL AUTO_INCREMENT, "
                 + "dataField VARCHAR(64), PRIMARY KEY (priKey))");

         //
         // Insert one row that will generate an AUTO INCREMENT
         // key in the 'priKey' field
         //

         stmt.executeUpdate(
                 "INSERT INTO autoIncTutorial (dataField) "
                 + "values ('Can I Get the Auto Increment Field?')",
                 Statement.RETURN_GENERATED_KEYS);

         //
         // Example of using Statement.getGeneratedKeys()
         // to retrieve the value of an auto-increment
         // value
         //

         int autoIncKeyFromApi = -1;

         rs = stmt.getGeneratedKeys();

         if (rs.next()) {
             autoIncKeyFromApi = rs.getInt(1);
         } else {

             // throw an exception from here
         }

         rs.close();

         rs = null;

         System.out.println("Key returned from getGeneratedKeys():"
             + autoIncKeyFromApi);
     } finally {

         if (rs != null) {
             try {
                 rs.close();
             } catch (SQLException ex) {
                 // ignore
             }
         }

         if (stmt != null) {
             try {
                 stmt.close();
             } catch (SQLException ex) {
                 // ignore
             }
         }
     }

        Statement stmt = null;
        ResultSet rs = null;

        try {

         //
         // Create a Statement instance that we can use for
         // 'normal' result sets.

         stmt = conn.createStatement();

         //
         // Issue the DDL queries for the table for this example
         //

         stmt.executeUpdate("DROP TABLE IF EXISTS autoIncTutorial");
         stmt.executeUpdate(
                 "CREATE TABLE autoIncTutorial ("
                 + "priKey INT NOT NULL AUTO_INCREMENT, "
                 + "dataField VARCHAR(64), PRIMARY KEY (priKey))");

         //
         // Insert one row that will generate an AUTO INCREMENT
         // key in the 'priKey' field
         //

         stmt.executeUpdate(
                 "INSERT INTO autoIncTutorial (dataField) "
                 + "values ('Can I Get the Auto Increment Field?')");

         //
         // Use the MySQL LAST_INSERT_ID()
         // function to do the same thing as getGeneratedKeys()
         //

         int autoIncKeyFromFunc = -1;
         rs = stmt.executeQuery("SELECT LAST_INSERT_ID()");

         if (rs.next()) {
             autoIncKeyFromFunc = rs.getInt(1);
         } else {
             // throw an exception from here
         }

         rs.close();

         System.out.println("Key returned from " +
                            "'SELECT LAST_INSERT_ID()': " +
                            autoIncKeyFromFunc);

     } finally {

         if (rs != null) {
             try {
                 rs.close();
             } catch (SQLException ex) {
                 // ignore
             }
         }

         if (stmt != null) {
             try {
                 stmt.close();
             } catch (SQLException ex) {
                 // ignore
             }
         }
     }

        Statement stmt = null;
        ResultSet rs = null;

        try {

         //
         // Create a Statement instance that we can use for
         // 'normal' result sets as well as an 'updatable'
         // one, assuming you have a Connection 'conn' to
         // a MySQL database already available
         //

         stmt = conn.createStatement(java.sql.ResultSet.TYPE_FORWARD_ONLY,
                                     java.sql.ResultSet.CONCUR_UPDATABLE);

         //
         // Issue the DDL queries for the table for this example
         //

         stmt.executeUpdate("DROP TABLE IF EXISTS autoIncTutorial");
         stmt.executeUpdate(
                 "CREATE TABLE autoIncTutorial ("
                 + "priKey INT NOT NULL AUTO_INCREMENT, "
                 + "dataField VARCHAR(64), PRIMARY KEY (priKey))");

         //
         // Example of retrieving an AUTO INCREMENT key
         // from an updatable result set
         //

         rs = stmt.executeQuery("SELECT priKey, dataField "
            + "FROM autoIncTutorial");

         rs.moveToInsertRow();

         rs.updateString("dataField", "AUTO INCREMENT here?");
         rs.insertRow();

         //
         // the driver adds rows at the end
         //

         rs.last();

         //
         // We should now be on the row we just inserted
         //

         int autoIncKeyFromRS = rs.getInt("priKey");

         rs.close();

         rs = null;

         System.out.println("Key returned for inserted row: "
             + autoIncKeyFromRS);

     } finally {

         if (rs != null) {
             try {
                 rs.close();
             } catch (SQLException ex) {
                 // ignore
             }
         }

         if (stmt != null) {
             try {
                 stmt.close();
             } catch (SQLException ex) {
                 // ignore
             }
         }
     }

When you run the preceding example code, you should get the following
output: Key returned from `getGeneratedKeys()': 1 Key returned from
`SELECT LAST_INSERT_ID()': 1 Key returned for inserted row: 2 You
should be aware, that at times, it can be tricky to use the `SELECT
LAST_INSERT_ID()' query, as that function's value is scoped to a
connection. So, if some other query happens on the same connection, the
value will be overwritten. On the other hand, the `getGeneratedKeys()'
method is scoped by the Statement instance, so it can be used even if
other queries happen on the same connection, but not on the same
Statement instance.


File: manual.info,  Node: connector-j-usagenotes-j2ee,  Next: connector-j-usagenotes-troubleshooting,  Prev: connector-j-usagenotes-basic,  Up: connector-j-usagenotes

20.3.5.6 Using Connector/J with J2EE and Other Java Frameworks
..............................................................

* Menu:

* connector-j-usagenotes-j2ee-concepts::  General J2EE Concepts
* connector-j-usagenotes-tomcat::  Using Connector/J with Tomcat
* connector-j-usagenotes-jboss::  Using Connector/J with JBoss
* connector-j-usagenotes-spring-config::  Using Connector/J with Spring
* connector-j-usagenotes-glassfish-config::  Using Connector/J with GlassFish

This section describes how to use Connector/J in several contexts.


File: manual.info,  Node: connector-j-usagenotes-j2ee-concepts,  Next: connector-j-usagenotes-tomcat,  Prev: connector-j-usagenotes-j2ee,  Up: connector-j-usagenotes-j2ee

20.3.5.7 General J2EE Concepts
..............................

* Menu:

* connector-j-usagenotes-j2ee-concepts-connection-pooling::  Understanding Connection Pooling
* connector-j-usagenotes-j2ee-concepts-managing-load-balanced-connections::  Managing Load Balanced Connections
* connector-j-usagenotes-j2ee-concepts-load-balancing-failover::  Load Balancing Failover Policies

This section provides general background on J2EE concepts that pertain
to use of Connector/J.


File: manual.info,  Node: connector-j-usagenotes-j2ee-concepts-connection-pooling,  Next: connector-j-usagenotes-j2ee-concepts-managing-load-balanced-connections,  Prev: connector-j-usagenotes-j2ee-concepts,  Up: connector-j-usagenotes-j2ee-concepts

20.3.5.8 Understanding Connection Pooling
.........................................

Connection pooling is a technique of creating and managing a pool of
connections that are ready for use by any thread that needs them.

This technique of pooling connections is based on the fact that most
applications only need a thread to have access to a JDBC connection
when they are actively processing a transaction, which usually take
only milliseconds to complete. When not processing a transaction, the
connection would otherwise sit idle. Instead, connection pooling
enables the idle connection to be used by some other thread to do
useful work.

In practice, when a thread needs to do work against a MySQL or other
database with JDBC, it requests a connection from the pool. When the
thread is finished using the connection, it returns it to the pool, so
that it can be used by any other threads.

When the connection is loaned out from the pool, it is used exclusively
by the thread that requested it. From a programming point of view, it
is the same as if your thread called `DriverManager.getConnection()'
every time it needed a JDBC connection, however with connection
pooling, your thread may end up using either a new, or already-existing
connection.

Connection pooling can greatly increase the performance of your Java
application, while reducing overall resource usage. The main benefits
to connection pooling are:

   * Reduced connection creation time

     Although this is not usually an issue with the quick connection
     setup that MySQL offers compared to other databases, creating new
     JDBC connections still incurs networking and JDBC driver overhead
     that will be avoided if connections are recycled.

   * Simplified programming model

     When using connection pooling, each individual thread can act as
     though it has created its own JDBC connection, allowing you to use
     straight-forward JDBC programming techniques.

   * Controlled resource usage

     If you do not use connection pooling, and instead create a new
     connection every time a thread needs one, your application's
     resource usage can be quite wasteful and lead to unpredictable
     behavior under load.

Remember that each connection to MySQL has overhead (memory, CPU,
context switches, and so forth) on both the client and server side.
Every connection limits how many resources there are available to your
application as well as the MySQL server. Many of these resources will
be used whether or not the connection is actually doing any useful work!

Connection pools can be tuned to maximize performance, while keeping
resource utilization below the point where your application will start
to fail rather than just run slower.

Luckily, Sun has standardized the concept of connection pooling in JDBC
through the JDBC-2.0 Optional interfaces, and all major application
servers have implementations of these APIs that work fine with MySQL
Connector/J.

Generally, you configure a connection pool in your application server
configuration files, and access it through the Java Naming and
Directory Interface (JNDI). The following code shows how you might use
a connection pool from an application deployed in a J2EE application
server:

     import java.sql.Connection;
     import java.sql.SQLException;
     import java.sql.Statement;

     import javax.naming.InitialContext;
     import javax.sql.DataSource;

     public class MyServletJspOrEjb {

         public void doSomething() throws Exception {
             /*
              * Create a JNDI Initial context to be able to
              *  lookup  the DataSource
              *
              * In production-level code, this should be cached as
              * an instance or static variable, as it can
              * be quite expensive to create a JNDI context.
              *
              * Note: This code only works when you are using servlets
              * or EJBs in a J2EE application server. If you are
              * using connection pooling in standalone Java code, you
              * will have to create/configure datasources using whatever
              * mechanisms your particular connection pooling library
              * provides.
              */

             InitialContext ctx = new InitialContext();

              /*
               * Lookup the DataSource, which will be backed by a pool
               * that the application server provides. DataSource instances
               * are also a good candidate for caching as an instance
               * variable, as JNDI lookups can be expensive as well.
               */

             DataSource ds =
               (DataSource)ctx.lookup("java:comp/env/jdbc/MySQLDB");

             /*
              * The following code is what would actually be in your
              * Servlet, JSP or EJB 'service' method...where you need
              * to work with a JDBC connection.
              */

             Connection conn = null;
             Statement stmt = null;

             try {
                 conn = ds.getConnection();

                 /*
                  * Now, use normal JDBC programming to work with
                  * MySQL, making sure to close each resource when you're
                  * finished with it, which permits the connection pool
                  * resources to be recovered as quickly as possible
                  */

                 stmt = conn.createStatement();
                 stmt.execute("SOME SQL QUERY");

                 stmt.close();
                 stmt = null;

                 conn.close();
                 conn = null;
             } finally {
                 /*
                  * close any jdbc instances here that weren't
                  * explicitly closed during normal code path, so
                  * that we don't 'leak' resources...
                  */

                 if (stmt != null) {
                     try {
                         stmt.close();
                     } catch (sqlexception sqlex) {
                         // ignore -- as we can't do anything about it here
                     }

                     stmt = null;
                 }

                 if (conn != null) {
                     try {
                         conn.close();
                     } catch (sqlexception sqlex) {
                         // ignore -- as we can't do anything about it here
                     }

                     conn = null;
                 }
             }
         }
     }

As shown in the example above, after obtaining the JNDI InitialContext,
and looking up the DataSource, the rest of the code should look
familiar to anyone who has done JDBC programming in the past.

The most important thing to remember when using connection pooling is
to make sure that no matter what happens in your code (exceptions,
flow-of-control, and so forth), connections, and anything created by
them (such as statements or result sets) are closed, so that they may be
re-used, otherwise they will be stranded, which in the best case means
that the MySQL server resources they represent (such as buffers, locks,
or sockets) may be tied up for some time, or worst case, may be tied up
forever.

*What Is the Best Size for my Connection Pool?*

As with all other configuration rules-of-thumb, the answer is: it
depends. Although the optimal size depends on anticipated load and
average database transaction time, the optimum connection pool size is
smaller than you might expect. If you take Sun's Java Petstore blueprint
application for example, a connection pool of 15-20 connections can
serve a relatively moderate load (600 concurrent users) using MySQL and
Tomcat with response times that are acceptable.

To correctly size a connection pool for your application, you should
create load test scripts with tools such as Apache JMeter or The
Grinder, and load test your application.

An easy way to determine a starting point is to configure your
connection pool's maximum number of connections to be unbounded, run a
load test, and measure the largest amount of concurrently used
connections. You can then work backward from there to determine what
values of minimum and maximum pooled connections give the best
performance for your particular application.

*Validating Connections*

MySQL Connector/J has the ability to execute a lightweight ping against
a server, in order to validate the connection.  In the case of
load-balanced connections, this is performed against all active pooled
internal connections that are retained. This is beneficial to Java
applications using connection pools, as the pool can use this feature to
validate connections. Depending on your connection pool and
configuration, this validation can be carried out at different times:

  1. Before the pool returns a connection to the application.

  2. When the application returns a connection to the pool.

  3. During periodic checks of idle connections.

In order to use this feature you need to specify a validation query in
your connection pool that starts with `/* ping */'. Note the syntax
must be exactly as specified. This will cause the driver send a ping to
the server and return a fake, light-weight, result set.  When using a
`ReplicationConnection' or `LoadBalancedConnection', the ping will be
sent across all active connections.

It is critical that the syntax be specified correctly. For example,
consider the following snippets:

     sql = "/* PING */ SELECT 1";
     sql = "SELECT 1 /* ping*/";
     sql = "/*ping*/ SELECT 1";
     sql = " /* ping */ SELECT 1";
     sql = "/*to ping or not to ping*/ SELECT 1";

None of the above statements will work. This is because the ping syntax
is sensitive to whitespace, capitalization, and placement. The syntax
needs to be exact for reasons of efficiency, as this test is done for
every statement that is executed:


     protected static final String PING_MARKER = "/* ping */";
     ...
     if (sql.charAt(0) == '/') {
     if (sql.startsWith(PING_MARKER)) {
     doPingInstead();
     ...

All of the previous statements will issue a normal `SELECT' statement
and will *not* be transformed into the lightweight ping. Further, for
load-balanced connections the statement will be executed against one
connection in the internal pool, rather than validating each underlying
physical connection. This results in the non-active physical
connections assuming a stale state, and they may die. If Connector/J
then re-balances it may select a dead connection, resulting in an
exception being passed to the application. To help prevent this you can
use `loadBalanceValidateConnectionOnSwapServer' to validate the
connection before use.

If your Connector/J deployment uses a connection pool that allows you
to specify a validation query, this should be taken advantage of, but
ensure that the query starts _exactly_ with `/* ping */'. This is
particularly important if you are using the load-balancing or
replication-aware features of Connector/J, as it will help keep alive
connections which otherwise will go stale and die, causing problems
later.


File: manual.info,  Node: connector-j-usagenotes-j2ee-concepts-managing-load-balanced-connections,  Next: connector-j-usagenotes-j2ee-concepts-load-balancing-failover,  Prev: connector-j-usagenotes-j2ee-concepts-connection-pooling,  Up: connector-j-usagenotes-j2ee-concepts

20.3.5.9 Managing Load Balanced Connections
...........................................

Connector/J has long provided an effective means to distribute
read/write load across multiple MySQL server instances for Cluster or
master-master replication deployments, but until version 5.1.13,
managing such deployments frequently required a service outage to
redeploy a new configuration. Given that the ease of scaling out by
adding additional MySQL Cluster (server) instances is a key element in
that product offering, which is also naturally targeted at deployments
with very strict availability requirements, it was necessary to add
support for online changes of this nature. This is also critical for
online upgrades, as the alternative is to take a MySQL Cluster server
instance down hard, which will lose any in-process transactions and
will also generate application exceptions, if any application is trying
to use that particular server instance. Connector/J now has the ability
to dynamically configure load-balanced connections.

There are two connection string options associated with this
functionality:

   * `loadBalanceConnectionGroup' - This provides the ability to group
     connections from different sources. This allows you to manage
     these JDBC sources within a single class-loader in any combination
     you choose. If they use the same configuration, and you want to
     manage them as a logical single group, give them the same name.
     This is the key property for management, if you do not define a
     name (string) for `loadBalanceConnectionGroup', you cannot manage
     the connections. All load-balanced connections sharing the same
     `loadBalanceConnectionGroup' value, regardless of how the
     application creates them, will be managed together.

   * `loadBalanceEnableJMX' - The ability to manage the connections is
     exposed when you define a `loadBalanceConnectionGroup', but if you
     want to manage this externally, enable JMX by setting this
     property to `true'. This enables a JMX implementation, which
     exposes the management and monitoring operations of a connection
     group. Further, start your application with the
     `-Dcom.sun.management.jmxremote' JVM flag. You can then perform
     connect and perform operations using a JMX client such as
     `jconsole'.

Once a connection has been made using the correct connection string
options, a number of monitoring properties are available:

   * Current active host count

   * Current active physical connection count

   * Current active logical connection count

   * Total logical connections created

   * Total transaction count

The following management operations can also be performed:

   * Add host

   * Remove host

The JMX interface,
`com.mysql.jdbc.jmx.LoadBalanceConnectionGroupManagerMBean', has the
following methods:

   * int getActiveHostCount(String group);

   * int getTotalHostCount(String group);

   * long getTotalLogicalConnectionCount(String group);

   * long getActiveLogicalConnectionCount(String group);

   * long getActivePhysicalConnectionCount(String group);

   * long getTotalPhysicalConnectionCount(String group);

   * long getTotalTransactionCount(String group);

   * void removeHost(String group, String host) throws SQLException;

   * void stopNewConnectionsToHost(String group, String host) throws
     SQLException;

   * void addHost(String group, String host, boolean forExisting);

   * String getActiveHostsList(String group);

   * String getRegisteredConnectionGroups();

The `getRegisteredConnectionGroups()' method will return the names of
all connection groups defined in that class-loader.

You can test this setup with the following code:


     public class Test {

         private static String URL = "jdbc:mysql:loadbalance://" +
             "localhost:3306,localhost:3310/test?" +
             "loadBalanceConnectionGroup=first&loadBalanceEnableJMX=true";

         public static void main(String[] args) throws Exception {
             new Thread(new Repeater()).start();
             new Thread(new Repeater()).start();
             new Thread(new Repeater()).start();
         }

         static Connection getNewConnection() throws SQLException, ClassNotFoundException {
             Class.forName("com.mysql.jdbc.Driver");
             return DriverManager.getConnection(URL, "root", "");
         }

         static void executeSimpleTransaction(Connection c, int conn, int trans){
             try {
                 c.setAutoCommit(false);
                 Statement s = c.createStatement();
                 s.executeQuery("SELECT SLEEP(1) /* Connection: " + conn + ", transaction: " + trans + " */");
                 c.commit();
             } catch (SQLException e) {
                 e.printStackTrace();
             }
         }

         public static class Repeater implements Runnable {
             public void run() {
                 for(int i=0; i < 100; i++){
                     try {
                         Connection c = getNewConnection();
                         for(int j=0; j < 10; j++){
                             executeSimpleTransaction(c, i, j);
                             Thread.sleep(Math.round(100 * Math.random()));
                         }
                         c.close();
                         Thread.sleep(100);
                     } catch (Exception e) {
                         e.printStackTrace();
                     }
                 }
             }
         }
     }

After compiling, the application can be started with the
`-Dcom.sun.management.jmxremote' flag, to enable remote management.
`jconsole' can then be started. The Test main class will be listed by
jconsole. Select this and click `Connect'. You can then navigate to the
`com.mysql.jdbc.jmx.LoadBalanceConnectionGroupManager' bean. At this
point you can click on various operations and examine the returned
result.

If you now had an additional instance of MySQL running on port 3309,
you could ensure that Connector/J starts using it by using the
`addHost()', which is exposed in `jconsole'. Note that these operations
can be performed dynamically without having to stop the application
running.


File: manual.info,  Node: connector-j-usagenotes-j2ee-concepts-load-balancing-failover,  Prev: connector-j-usagenotes-j2ee-concepts-managing-load-balanced-connections,  Up: connector-j-usagenotes-j2ee-concepts

20.3.5.10 Load Balancing Failover Policies
..........................................

Connector/J provides a useful load-balancing implementation for Cluster
or multi-master deployments. As of Connector/J 5.1.12, this same
implementation is used for balancing load between read-only slaves with
`ReplicationDriver'. When trying to balance workload between multiple
servers, the driver has to determine when it is safe to swap servers,
doing so in the middle of a transaction, for example, could cause
problems.  It is important not to lose state information. For this
reason, Connector/J will only try to pick a new server when one of the
following happens:

  1. At transaction boundaries (transactions are explicitly committed
     or rolled back).

  2. A communication exception (SQL State starting with "08") is
     encountered.

  3. When a `SQLException' matches conditions defined by user, using
     the extension points defined by the `loadBalanceSQLStateFailover',
     `loadBalanceSQLExceptionSubclassFailover' or
     `loadBalanceExceptionChecker' properties.

The third condition revolves around three new properties introduced
with Connector/J 5.1.13. It allows you to control which `SQLException's
trigger failover.

   * `loadBalanceExceptionChecker' - The `loadBalanceExceptionChecker'
     property is really the key. This takes a fully-qualified class
     name which implements the new
     `com.mysql.jdbc.LoadBalanceExceptionChecker' interface. This
     interface is very simple, and you only need to implement the
     following method:

          public boolean shouldExceptionTriggerFailover(SQLException ex)

     A `SQLException' is passed in, and a boolean returned. `True'
     triggers a failover, `false' does not.

     You can use this to implement your own custom logic. An example
     where this might be useful is when dealing with transient errors
     when using MySQL Cluster, where certain buffers may become
     overloaded. The following code snippet illustrates this:


          public class NdbLoadBalanceExceptionChecker
           extends StandardLoadBalanceExceptionChecker {

           public boolean shouldExceptionTriggerFailover(SQLException ex) {
            return super.shouldExceptionTriggerFailover(ex)
              ||  checkNdbException(ex);
           }

           private boolean checkNdbException(SQLException ex){
           // Have to parse the message since most NDB errors
           // are mapped to the same DEMC.
            return (ex.getMessage().startsWith("Lock wait timeout exceeded") ||
            (ex.getMessage().startsWith("Got temporary error")
            && ex.getMessage().endsWith("from NDB")));
           }
          }

     The code above extends
     `com.mysql.jdbc.StandardLoadBalanceExceptionChecker', which is the
     default implementation. There are a few convenient shortcuts built
     into this, for those who want to have some level of control using
     properties, without writing Java code. This default implementation
     uses the two remaining properties: `loadBalanceSQLStateFailover'
     and `loadBalanceSQLExceptionSubclassFailover'.

   * `loadBalanceSQLStateFailover' - allows you to define a
     comma-delimited list of `SQLState' code prefixes, against which a
     `SQLException' is compared. If the prefix matches, failover is
     triggered. So, for example, the following would trigger a failover
     if a given `SQLException' starts with "00", or is "12345":

          loadBalanceSQLStateFailover=00,12345

   * `loadBalanceSQLExceptionSubclassFailover' - can be used in
     conjunction with `loadBalanceSQLStateFailover' or on its own. If
     you want certain subclasses of `SQLException' to trigger failover,
     simply provide a comma-delimited list of fully-qualified class or
     interface names to check against. For example, if you want all
     `SQLTransientConnectionExceptions' to trigger failover, you would
     specify:

          loadBalanceSQLExceptionSubclassFailover=java.sql.SQLTransientConnectionException

While the three fail-over conditions enumerated earlier suit most
situations, if `auto-commit' is enabled, Connector/J never re-balances,
and continues using the same physical connection. This can be
problematic, particularly when load-balancing is being used to
distribute read-only load across multiple slaves. However, Connector/J
can be configured to re-balance after a certain number of statements
are executed, when `auto-commit' is enabled. This functionality is
dependent upon the following properties:

   * `loadBalanceAutoCommitStatementThreshold' - defines the number of
     matching statements which will trigger the driver to potentially
     swap physical server connections. The default value, 0, retains
     the behavior that connections with `auto-commit' enabled are never
     balanced.

   * `loadBalanceAutoCommitStatementRegex' - the regular expression
     against which statements must match. The default value, blank,
     matches all statements.  So, for example, using the following
     properties will cause Connector/J to re-balance after every third
     statement that contains the string `test':

          loadBalanceAutoCommitStatementThreshold=3
          loadBalanceAutoCommitStatementRegex=.*test.*

     `loadBalanceAutoCommitStatementRegex' can prove useful in a number
     of situations. Your application may use temporary tables,
     server-side session state variables, or connection state, where
     letting the driver arbitrarily swap physical connections before
     processing is complete could cause data loss or other problems.
     This allows you to identify a trigger statement that is only
     executed when it is safe to swap physical connections.


File: manual.info,  Node: connector-j-usagenotes-tomcat,  Next: connector-j-usagenotes-jboss,  Prev: connector-j-usagenotes-j2ee-concepts,  Up: connector-j-usagenotes-j2ee

20.3.5.11 Using Connector/J with Tomcat
.......................................

The following instructions are based on the instructions for
Tomcat-5.x, available at
`http://tomcat.apache.org/tomcat-5.5-doc/jndi-datasource-examples-howto.html'
which is current at the time this document was written.

First, install the .jar file that comes with Connector/J in
`$CATALINA_HOME/common/lib' so that it is available to all applications
installed in the container.

Next, Configure the JNDI DataSource by adding a declaration resource to
`$CATALINA_HOME/conf/server.xml' in the context that defines your web
application:

     <Context ....>

       ...

       <Resource name="jdbc/MySQLDB"
                    auth="Container"
                    type="javax.sql.DataSource"/>

       <!-- The name you used above, must match _exactly_ here!

            The connection pool will be bound into JNDI with the name
            "java:/comp/env/jdbc/MySQLDB"
       -->

       <ResourceParams name="jdbc/MySQLDB">
         <parameter>
           <name>factory</name>
           <value>org.apache.commons.dbcp.BasicDataSourceFactory</value>
         </parameter>

         <!-- Don't set this any higher than max_connections on your
              MySQL server, usually this should be a 10 or a few 10's
              of connections, not hundreds or thousands -->

         <parameter>
           <name>maxActive</name>
           <value>10</value>
         </parameter>

         <!-- You don't want to many idle connections hanging around
              if you can avoid it, only enough to soak up a spike in
              the load -->

         <parameter>
           <name>maxIdle</name>
           <value>5</value>
         </parameter>

         <!-- Don't use autoReconnect=true, it's going away eventually
              and it's a crutch for older connection pools that couldn't
              test connections. You need to decide whether your application
              is supposed to deal with SQLExceptions (hint, it should), and
              how much of a performance penalty you're willing to pay
              to ensure 'freshness' of the connection -->

         <parameter>
           <name>validationQuery</name>
           <value>SELECT 1</value> <-- See discussion below for update to this option -->
         </parameter>

        <!-- The most conservative approach is to test connections
             before they're given to your application. For most applications
             this is okay, the query used above is very small and takes
             no real server resources to process, other than the time used
             to traverse the network.

             If you have a high-load application you'll need to rely on
             something else. -->

         <parameter>
           <name>testOnBorrow</name>
           <value>true</value>
         </parameter>

        <!-- Otherwise, or in addition to testOnBorrow, you can test
             while connections are sitting idle -->

         <parameter>
           <name>testWhileIdle</name>
           <value>true</value>
         </parameter>

         <!-- You have to set this value, otherwise even though
              you've asked connections to be tested while idle,
              the idle evicter thread will never run -->

         <parameter>
           <name>timeBetweenEvictionRunsMillis</name>
           <value>10000</value>
         </parameter>

         <!-- Don't allow connections to hang out idle too long,
              never longer than what wait_timeout is set to on the
              server...A few minutes or even fraction of a minute
              is sometimes okay here, it depends on your application
              and how much spikey load it will see -->

         <parameter>
           <name>minEvictableIdleTimeMillis</name>
           <value>60000</value>
         </parameter>

         <!-- Username and password used when connecting to MySQL -->

         <parameter>
          <name>username</name>
          <value>someuser</value>
         </parameter>

         <parameter>
          <name>password</name>
          <value>somepass</value>
         </parameter>

         <!-- Class name for the Connector/J driver -->

         <parameter>
            <name>driverClassName</name>
            <value>com.mysql.jdbc.Driver</value>
         </parameter>

         <!-- The JDBC connection url for connecting to MySQL, notice
              that if you want to pass any other MySQL-specific parameters
              you should pass them here in the URL, setting them using the
              parameter tags above will have no effect, you will also
              need to use &amp; to separate parameter values as the
              ampersand is a reserved character in XML -->

         <parameter>
           <name>url</name>
           <value>jdbc:mysql://localhost:3306/test</value>
         </parameter>

       </ResourceParams>
     </Context>

Note that Connector/J 5.1.3 introduced a facility whereby, rather than
use a `validationQuery' value of `SELECT 1', it is possible to use
`validationQuery' with a value set to `/* ping */'. This sends a ping
to the server which then returns a fake result set. This is a lighter
weight solution. It also has the advantage that if using
`ReplicationConnection' or `LoadBalancedConnection' type connections,
the ping will be sent across all active connections. The following XML
snippet illustrates how to select this option:


     <parameter>
      <name>validationQuery</name>
      <value>/* ping */</value>
     </parameter>

Note that `/* ping */' has to be specified exactly.

In general, you should follow the installation instructions that come
with your version of Tomcat, as the way you configure datasources in
Tomcat changes from time-to-time, and unfortunately if you use the
wrong syntax in your XML file, you will most likely end up with an
exception similar to the following:

     Error: java.sql.SQLException: Cannot load JDBC driver class 'null ' SQL
     state: null


File: manual.info,  Node: connector-j-usagenotes-jboss,  Next: connector-j-usagenotes-spring-config,  Prev: connector-j-usagenotes-tomcat,  Up: connector-j-usagenotes-j2ee

20.3.5.12 Using Connector/J with JBoss
......................................

These instructions cover JBoss-4.x. To make the JDBC driver classes
available to the application server, copy the .jar file that comes with
Connector/J to the `lib' directory for your server configuration (which
is usually called `default'). Then, in the same configuration
directory, in the subdirectory named deploy, create a datasource
configuration file that ends with "-ds.xml", which tells JBoss to
deploy this file as a JDBC Datasource. The file should have the
following contents:

     <datasources>
         <local-tx-datasource>
             <!-- This connection pool will be bound into JNDI with the name
                  "java:/MySQLDB" -->

             <jndi-name>MySQLDB</jndi-name>
             <connection-url>jdbc:mysql://localhost:3306/dbname</connection-url>
             <driver-class>com.mysql.jdbc.Driver</driver-class>
             <user-name>user</user-name>
             <password>pass</password>

             <min-pool-size>5</min-pool-size>

             <!-- Don't set this any higher than max_connections on your
              MySQL server, usually this should be a 10 or a few 10's
              of connections, not hundreds or thousands -->

             <max-pool-size>20</max-pool-size>

             <!-- Don't allow connections to hang out idle too long,
              never longer than what wait_timeout is set to on the
              server...A few minutes is usually okay here,
              it depends on your application
              and how much spikey load it will see -->

             <idle-timeout-minutes>5</idle-timeout-minutes>

             <!-- If you're using Connector/J 3.1.8 or newer, you can use
                  our implementation of these to increase the robustness
                  of the connection pool. -->

             <exception-sorter-class-name>
       com.mysql.jdbc.integration.jboss.ExtendedMysqlExceptionSorter
             </exception-sorter-class-name>
             <valid-connection-checker-class-name>
       com.mysql.jdbc.integration.jboss.MysqlValidConnectionChecker
             </valid-connection-checker-class-name>

         </local-tx-datasource>
     </datasources>


File: manual.info,  Node: connector-j-usagenotes-spring-config,  Next: connector-j-usagenotes-glassfish-config,  Prev: connector-j-usagenotes-jboss,  Up: connector-j-usagenotes-j2ee

20.3.5.13 Using Connector/J with Spring
.......................................

* Menu:

* connector-j-usagenotes-spring-config-jdbctemplate::  Using JdbcTemplate
* connector-j-usagenotes-spring-config-transactional::  Transactional JDBC Access
* connector-j-usagenotes-spring-config-connpooling::  Connection Pooling

The Spring Framework is a Java-based application framework designed for
assisting in application design by providing a way to configure
components. The technique used by Spring is a well known design pattern
called Dependency Injection (see Inversion of Control Containers and
the Dependency Injection pattern
(http://www.martinfowler.com/articles/injection.html)). This article
will focus on Java-oriented access to MySQL databases with Spring 2.0.
For those wondering, there is a .NET port of Spring appropriately named
Spring.NET.

Spring is not only a system for configuring components, but also
includes support for aspect oriented programming (AOP).  This is one of
the main benefits and the foundation for Spring's resource and
transaction management. Spring also provides utilities for integrating
resource management with JDBC and Hibernate.

For the examples in this section the MySQL world sample database will
be used. The first task is to set up a MySQL data source through
Spring. Components within Spring use the "bean" terminology. For
example, to configure a connection to a MySQL server supporting the
world sample database you might use:

     <util:map id="dbProps">
         <entry key="db.driver" value="com.mysql.jdbc.Driver"/>
         <entry key="db.jdbcurl" value="jdbc:mysql://localhost/world"/>
         <entry key="db.username" value="myuser"/>
         <entry key="db.password" value="mypass"/>
     </util:map>

In the above example we are assigning values to properties that will be
used in the configuration. For the datasource configuration:

     <bean id="dataSource"
            class="org.springframework.jdbc.datasource.DriverManagerDataSource">
         <property name="driverClassName" value="${db.driver}"/>
         <property name="url" value="${db.jdbcurl}"/>
         <property name="username" value="${db.username}"/>
         <property name="password" value="${db.password}"/>
     </bean>

The placeholders are used to provide values for properties of this
bean. This means that you can specify all the properties of the
configuration in one place instead of entering the values for each
property on each bean. We do, however, need one more bean to pull this
all together. The last bean is responsible for actually replacing the
placeholders with the property values.

     <bean
      class="org.springframework.beans.factory.config.PropertyPlaceholderConfigurer">
         <property name="properties" ref="dbProps"/>
     </bean>

Now that we have our MySQL data source configured and ready to go, we
write some Java code to access it. The example below will retrieve
three random cities and their corresponding country using the data
source we configured with Spring.

     // Create a new application context. this processes the Spring config
     ApplicationContext ctx =
         new ClassPathXmlApplicationContext("ex1appContext.xml");
     // Retrieve the data source from the application context
         DataSource ds = (DataSource) ctx.getBean("dataSource");
     // Open a database connection using Spring's DataSourceUtils
     Connection c = DataSourceUtils.getConnection(ds);
     try {
         // retrieve a list of three random cities
         PreparedStatement ps = c.prepareStatement(
             "select City.Name as 'City', Country.Name as 'Country' " +
             "from City inner join Country on City.CountryCode = Country.Code " +
             "order by rand() limit 3");
         ResultSet rs = ps.executeQuery();
         while(rs.next()) {
             String city = rs.getString("City");
             String country = rs.getString("Country");
             System.out.printf("The city %s is in %s%n", city, country);
         }
     } catch (SQLException ex) {
         // something has failed and we print a stack trace to analyse the error
         ex.printStackTrace();
         // ignore failure closing connection
         try { c.close(); } catch (SQLException e) { }
     } finally {
         // properly release our connection
         DataSourceUtils.releaseConnection(c, ds);
     }

This is very similar to normal JDBC access to MySQL with the main
difference being that we are using DataSourceUtils instead of the
DriverManager to create the connection.

While it may seem like a small difference, the implications are
somewhat far reaching. Spring manages this resource in a way similar to
a container managed data source in a J2EE application server. When a
connection is opened, it can be subsequently accessed in other parts of
the code if it is synchronized with a transaction. This makes it
possible to treat different parts of your application as transactional
instead of passing around a database connection.


File: manual.info,  Node: connector-j-usagenotes-spring-config-jdbctemplate,  Next: connector-j-usagenotes-spring-config-transactional,  Prev: connector-j-usagenotes-spring-config,  Up: connector-j-usagenotes-spring-config

20.3.5.14 Using JdbcTemplate
............................

Spring makes extensive use of the Template method design pattern (see
Template Method Pattern
(http://en.wikipedia.org/wiki/Template_method_pattern)). Our immediate
focus will be on the `JdbcTemplate' and related classes, specifically
`NamedParameterJdbcTemplate'.  The template classes handle obtaining
and releasing a connection for data access when one is needed.

The next example shows how to use `NamedParameterJdbcTemplate' inside
of a DAO (Data Access Object) class to retrieve a random city given a
country code.

     public class Ex2JdbcDao {
          /**
          * Data source reference which will be provided by Spring.
          */
          private DataSource dataSource;

          /**
          * Our query to find a random city given a country code. Notice
          * the ":country" parameter toward the end. This is called a
          * named parameter.
          */
          private String queryString = "select Name from City " +
             "where CountryCode = :country order by rand() limit 1";

          /**
          * Retrieve a random city using Spring JDBC access classes.
          */
          public String getRandomCityByCountryCode(String cntryCode) {
              // A template that permits using queries with named parameters
              NamedParameterJdbcTemplate template =
              new NamedParameterJdbcTemplate(dataSource);
              // A java.util.Map is used to provide values for the parameters
              Map params = new HashMap();
              params.put("country", cntryCode);
              // We query for an Object and specify what class we are expecting
              return (String)template.queryForObject(queryString, params, String.class);
          }

         /**
         * A JavaBean setter-style method to allow Spring to inject the data source.
         * @param dataSource
         */
         public void setDataSource(DataSource dataSource) {
             this.dataSource = dataSource;
         }
     }

The focus in the above code is on the `getRandomCityByCountryCode()'
method. We pass a country code and use the `NamedParameterJdbcTemplate'
to query for a city. The country code is placed in a Map with the key
"country", which is the parameter is named in the SQL query.

To access this code, you need to configure it with Spring by providing
a reference to the data source.

     <bean id="dao" class="code.Ex2JdbcDao">
         <property name="dataSource" ref="dataSource"/>
     </bean>

At this point, we can just grab a reference to the DAO from Spring and
call `getRandomCityByCountryCode()'.

     // Create the application context
         ApplicationContext ctx =
         new ClassPathXmlApplicationContext("ex2appContext.xml");
         // Obtain a reference to our DAO
         Ex2JdbcDao dao = (Ex2JdbcDao) ctx.getBean("dao");

         String countryCode = "USA";

         // Find a few random cities in the US
         for(int i = 0; i < 4; ++i)
             System.out.printf("A random city in %s is %s%n", countryCode,
                 dao.getRandomCityByCountryCode(countryCode));

This example shows how to use Spring's JDBC classes to completely
abstract away the use of traditional JDBC classes including
`Connection' and `PreparedStatement'.


File: manual.info,  Node: connector-j-usagenotes-spring-config-transactional,  Next: connector-j-usagenotes-spring-config-connpooling,  Prev: connector-j-usagenotes-spring-config-jdbctemplate,  Up: connector-j-usagenotes-spring-config

20.3.5.15 Transactional JDBC Access
...................................

You might be wondering how we can add transactions into our code if we
do not deal directly with the JDBC classes.  Spring provides a
transaction management package that not only replaces JDBC transaction
management, but also enables declarative transaction management
(configuration instead of code).

To use transactional database access, we will need to change the
storage engine of the tables in the world database. The downloaded
script explicitly creates MyISAM tables which do not support
transactional semantics. The InnoDB storage engine does support
transactions and this is what we will be using. We can change the
storage engine with the following statements.

     ALTER TABLE City ENGINE=InnoDB;
     ALTER TABLE Country ENGINE=InnoDB;
     ALTER TABLE CountryLanguage ENGINE=InnoDB;

A good programming practice emphasized by Spring is separating
interfaces and implementations. What this means is that we can create a
Java interface and only use the operations on this interface without
any internal knowledge of what the actual implementation is. We will
let Spring manage the implementation and with this it will manage the
transactions for our implementation.

First you create a simple interface:

     public interface Ex3Dao {
         Integer createCity(String name, String countryCode,
         String district, Integer population);
     }

This interface contains one method that will create a new city record
in the database and return the id of the new record. Next you need to
create an implementation of this interface.

     public class Ex3DaoImpl implements Ex3Dao {
         protected DataSource dataSource;
         protected SqlUpdate updateQuery;
         protected SqlFunction idQuery;

         public Integer createCity(String name, String countryCode,
             String district, Integer population) {
                 updateQuery.update(new Object[] { name, countryCode,
                        district, population });
                 return getLastId();
             }

         protected Integer getLastId() {
             return idQuery.run();
         }
     }

You can see that we only operate on abstract query objects here and do
not deal directly with the JDBC API. Also, this is the complete
implementation. All of our transaction management will be dealt with in
the configuration. To get the configuration started, we need to create
the DAO.

     <bean id="dao" class="code.Ex3DaoImpl">
         <property name="dataSource" ref="dataSource"/>
         <property name="updateQuery">...</property>
         <property name="idQuery">...</property>
     </bean>

Now you need to set up the transaction configuration. The first thing
you must do is create transaction manager to manage the data source and
a specification of what transaction properties are required for the
`dao' methods.

     <bean id="transactionManager"
       class="org.springframework.jdbc.datasource.DataSourceTransactionManager">
         <property name="dataSource" ref="dataSource"/>
     </bean>

     <tx:advice id="txAdvice" transaction-manager="transactionManager">
         <tx:attributes>
             <tx:method name="*"/>
         </tx:attributes>
     </tx:advice>

The preceding code creates a transaction manager that handles
transactions for the data source provided to it. The `txAdvice' uses
this transaction manager and the attributes specify to create a
transaction for all methods. Finally you need to apply this advice with
an AOP pointcut.

     <aop:config>
         <aop:pointcut id="daoMethods"
             expression="execution(* code.Ex3Dao.*(..))"/>
          <aop:advisor advice-ref="txAdvice" pointcut-ref="daoMethods"/>
     </aop:config>

This basically says that all methods called on the `Ex3Dao' interface
will be wrapped in a transaction. To make use of this, you only have to
retrieve the `dao' from the application context and call a method on
the `dao' instance.

     Ex3Dao dao = (Ex3Dao) ctx.getBean("dao");
     Integer id = dao.createCity(name,  countryCode, district, pop);

We can verify from this that there is no transaction management
happening in our Java code and it is all configured with Spring. This
is a very powerful notion and regarded as one of the most beneficial
features of Spring.


File: manual.info,  Node: connector-j-usagenotes-spring-config-connpooling,  Prev: connector-j-usagenotes-spring-config-transactional,  Up: connector-j-usagenotes-spring-config

20.3.5.16 Connection Pooling
............................

In many situations, such as web applications, there will be a large
number of small database transactions. When this is the case, it
usually makes sense to create a pool of database connections available
for web requests as needed.  Although MySQL does not spawn an extra
process when a connection is made, there is still a small amount of
overhead to create and set up the connection. Pooling of connections
also alleviates problems such as collecting large amounts of sockets in
the `TIME_WAIT' state.

Setting up pooling of MySQL connections with Spring is as simple as
changing the data source configuration in the application context.
There are a number of configurations that we can use. The first example
is based on the Jakarta Commons DBCP library
(http://jakarta.apache.org/commons/dbcp/). The example below replaces
the source configuration that was based on `DriverManagerDataSource'
with DBCP's BasicDataSource.

     <bean id="dataSource" destroy-method="close"
       class="org.apache.commons.dbcp.BasicDataSource">
         <property name="driverClassName" value="${db.driver}"/>
         <property name="url" value="${db.jdbcurl}"/>
         <property name="username" value="${db.username}"/>
         <property name="password" value="${db.password}"/>
         <property name="initialSize" value="3"/>
     </bean>

The configuration of the two solutions is very similar. The difference
is that DBCP will pool connections to the database instead of creating
a new connection every time one is requested. We have also set a
parameter here called `initialSize'. This tells DBCP that we want three
connections in the pool when it is created.

Another way to configure connection pooling is to configure a data
source in our J2EE application server. Using JBoss as an example, you
can set up the MySQL connection pool by creating a file called
`mysql-local-ds.xml' and placing it in the server/default/deploy
directory in JBoss. Once we have this setup, we can use JNDI to look it
up. With Spring, this lookup is very simple. The data source
configuration looks like this.

     <jee:jndi-lookup id="dataSource" jndi-name="java:MySQL_DS"/>


File: manual.info,  Node: connector-j-usagenotes-glassfish-config,  Prev: connector-j-usagenotes-spring-config,  Up: connector-j-usagenotes-j2ee

20.3.5.17 Using Connector/J with GlassFish
..........................................

* Menu:

* connector-j-usagenotes-glassfish-config-jsp::  A Simple JSP Application with Glassfish, Connector/J and MySQL
* connector-j-usagenotes-glassfish-config-servlet::  A Simple Servlet with Glassfish, Connector/J and MySQL

This section explains how to use MySQL Connector/J with Glassfish (tm)
Server Open Source Edition 3.0.1. Glassfish can be downloaded from the
Glassfish website
(https://glassfish.dev.java.net/public/downloadsindex.html#top).

Once Glassfish is installed you will need to make sure it can access
MySQL Connector/J. To do this copy the MySQL Connector/J JAR file to the
directory `GLASSFISH_INSTALL/glassfish/lib'.  For example, copy
`mysql-connector-java-5.1.12-bin.jar' to
`C:\glassfishv3\glassfish\lib'. Restart the Glassfish Application
Server.

You are now ready to create JDBC Connection Pools and JDBC Resources.

*Creating a Connection Pool*

  1. In the Glassfish Administration Console, using the navigation tree
     navigate to `Resources', `JDBC', `Connection Pools'.

  2. In the `JDBC Connection Pools' frame click `New'. You will enter a
     two step wizard.

  3. In the `Name' field under `General Settings' enter the name for
     the connection pool, for example enter MySQLConnPool.

  4. In the `Resource Type' field, select `javax.sql.DataSource' from
     the drop-down listbox.

  5. In the `Database Vendor' field, select `MySQL' from the drop-down
     listbox. Click `Next' to go to the next page of the wizard.

  6. You can accept the default settings for General Settings, Pool
     Settings and Transactions for this example. Scroll down to
     Additional Properties.

  7. In Additional Properties you will need to ensure the following
     properties are set:

        * *ServerName* - The server to connect to. For local testing
          this will be `localhost'.

        * *User* - The user name with which to connect to MySQL.

        * *Password* - The corresponding password for the user.

        * *DatabaseName* - The database to connect to, for example the
          sample MySQL database `World'.

  8. Click `Finish' to exit the wizard.  You will be taken to the `JDBC
     Connection Pools' page where all current connection pools,
     including the one you just created, will be displayed.

  9. In the `JDBC Connection Pools' frame click on the connection pool
     you just created. Here you can review and edit information about
     the connection pool.

 10. To test your connection pool click the `Ping' button at the top of
     the frame. A message will be displayed confirming correct
     operation or otherwise. If an error message is received recheck
     the previous steps, and ensure that MySQL Connector/J has been
     correctly copied into the previously specified location.

Now that you have created a connection pool you will also need to
create a JDBC Resource (data source) for use by your application.

*Creating a JDBC Resource*

Your Java application will usually reference a data source object to
establish a connection with the database. This needs to be created
first using the following procedure.

   * Using the navigation tree in the Glassfish Administration Console,
     navigate to `Resources', `JDBC', `JDBC Resources'. A list of
     resources will be displayed in the `JDBC Resources' frame.

   * Click `New'. The `New JDBC Resource' frame will be displayed.

   * In the `JNDI Name' field, enter the JNDI name that will be used to
     access this resource, for example enter jdbc/MySQLDataSource.

   * In the `Pool Name' field, select a connection pool you want this
     resource to use from the drop-down listbox.

   * Optionally, you can enter a description into the `Description'
     field.

   * Additional properties can be added if required.

   * Click `OK' to create the new JDBC resource. The `JDBC Resources'
     frame will list all available JDBC Resources.


File: manual.info,  Node: connector-j-usagenotes-glassfish-config-jsp,  Next: connector-j-usagenotes-glassfish-config-servlet,  Prev: connector-j-usagenotes-glassfish-config,  Up: connector-j-usagenotes-glassfish-config

20.3.5.18 A Simple JSP Application with Glassfish, Connector/J and MySQL
........................................................................

This section shows how to deploy a simple JSP application on Glassfish,
that connects to a MySQL database.

This example assumes you have already set up a suitable Connection Pool
and JDBC Resource, as explained in the preceding sections. It is also
assumed you have a sample database installed, such as `world'.

The main application code, `index.jsp' is presented here:


     <%@ page import="java.sql.*, javax.sql.*, java.io.*, javax.naming.*" %>
     <html>
     <head><title>Hello world from JSP</title></head>
     <body>
     <%
       InitialContext ctx;
       DataSource ds;
       Connection conn;
       Statement stmt;
       ResultSet rs;

       try {
         ctx = new InitialContext();
         ds = (DataSource) ctx.lookup("java:comp/env/jdbc/MySQLDataSource");
         //ds = (DataSource) ctx.lookup("jdbc/MySQLDataSource");
         conn = ds.getConnection();
         stmt = conn.createStatement();
         rs = stmt.executeQuery("SELECT * FROM Country");

         while(rs.next()) {
     %>
         <h3>Name: <%= rs.getString("Name") %></h3>
         <h3>Population: <%= rs.getString("Population") %></h3>
     <%
         }
       }
       catch (SQLException se) {
     %>
         <%= se.getMessage() %>
     <%
       }
       catch (NamingException ne) {
     %>
         <%= ne.getMessage() %>
     <%
       }
     %>
     </body>
     </html>

In addition two XML files are required: `web.xml', and `sun-web.xml'.
There may be other files present, such as classes and images. These
files are organized into the directory structure as follows:

     index.jsp
     WEB-INF
        |
        - web.xml
        - sun-web.xml

The code for `web.xml' is:


     <?xml version="1.0" encoding="UTF-8"?>
     <web-app version="2.4" xmlns="http://java.sun.com/xml/ns/j2ee" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://java.sun.com/xml/ns/j2ee http://java.sun.com/xml/ns/j2ee/web-app_2_4.xsd">
       <display-name>HelloWebApp</display-name>
       <distributable/>
       <resource-ref>
         <res-ref-name>jdbc/MySQLDataSource</res-ref-name>
         <res-type>javax.sql.DataSource</res-type>
         <res-auth>Container</res-auth>
         <res-sharing-scope>Shareable</res-sharing-scope>
       </resource-ref>
     </web-app>

The code for `sun-web.xml' is:


     <?xml version="1.0" encoding="UTF-8"?>
     <!DOCTYPE sun-web-app PUBLIC "-//Sun Microsystems, Inc.//DTD Application Server 8.1 Servlet 2.4//EN" "http://www.sun.com/software/appserver/dtds/sun-web-app_2_4-1.dtd">
     <sun-web-app>
       <context-root>HelloWebApp</context-root>
       <resource-ref>
         <res-ref-name>jdbc/MySQLDataSource</res-ref-name>
         <jndi-name>jdbc/MySQLDataSource</jndi-name>
       </resource-ref>
     </sun-web-app>

These XML files illustrate a very important aspect of running JDBC
applications on Glassfish. On Glassfish it is important to map the
string specified for a JDBC resource to its JNDI name, as set up in the
Glassfish administration console. In this example, the JNDI name for
the JDBC resource, as specified in the Glassfish Administration console
when creating the JDBC Resource, was `jdbc/MySQLDataSource'. This must
be mapped to the name given in the application. In this example the
name specified in the application, `jdbc/MySQLDataSource', and the JNDI
name, happen to be the same, but this does not necessarily have to be
the case. Note that the XML element <res-ref-name> is used to specify
the name as used in the application source code, and this is mapped to
the JNDI name specified using the <jndi-name> element, in the file
`sun-web.xml'. The resource also has to be created in the `web.xml'
file, although the mapping of the resource to a JNDI name takes place
in the `sun-web.xml' file.

If you do not have this mapping set up correctly in the XML files you
will not be able to lookup the data source using a JNDI lookup string
such as:

     ds = (DataSource) ctx.lookup("java:comp/env/jdbc/MySQLDataSource");

You will still be able to access the data source directly using:

     ds = (DataSource) ctx.lookup("jdbc/MySQLDataSource");

With the source files in place, in the correct directory structure, you
are ready to deploy the application:

  1. In the navigation tree, navigate to `Applications' - the
     `Applications' frame will be displayed. Click `Deploy'.

  2. You can now deploy an application packaged into a single WAR file
     from a remote client, or you can choose a packaged file or
     directory that is locally accessible to the server. If you are
     simply testing an application locally you can simply point
     Glassfish at the directory that contains your application, without
     needing to package the application into a WAR file.

  3. Now select the application type from the `Type' drop-down listbox,
     which in this example is `Web application'.

  4. Click OK.

Now, when you navigate to the `Applications' frame, you will have the
option to `Launch', `Redeploy', or `Restart' your application. You can
test your application by clicking `Launch'.  The application will
connection to the MySQL database and display the Name and Population of
countries in the `Country' table.


File: manual.info,  Node: connector-j-usagenotes-glassfish-config-servlet,  Prev: connector-j-usagenotes-glassfish-config-jsp,  Up: connector-j-usagenotes-glassfish-config

20.3.5.19 A Simple Servlet with Glassfish, Connector/J and MySQL
................................................................

This section describes a simple servlet that can be used in the
Glassfish environment to access a MySQL database. As with the previous
section, this example assumes the sample database `world' is installed.

The project is set up with the following directory structure:

     index.html
     WEB-INF
        |
        - web.xml
        - sun-web.xml
        - classes
             |
             - HelloWebServlet.java
             - HelloWebServlet.class

The code for the servlet, located in `HelloWebServlet.java', is as
follows:


     import javax.servlet.http.*;
     import javax.servlet.*;
     import java.io.*;
     import java.sql.*;
     import javax.sql.*;
     import javax.naming.*;

     public class HelloWebServlet extends HttpServlet {

       InitialContext ctx = null;
       DataSource ds = null;
       Connection conn = null;
       PreparedStatement ps = null;
       ResultSet rs = null;

       String sql = "SELECT Name, Population FROM Country WHERE Name=?";

       public void init () throws ServletException {
         try {
           ctx = new InitialContext();
           ds = (DataSource) ctx.lookup("java:comp/env/jdbc/MySQLDataSource");
           conn = ds.getConnection();
           ps = conn.prepareStatement(sql);
         }
         catch (SQLException se) {
           System.out.println("SQLException: "+se.getMessage());
         }
         catch (NamingException ne) {
           System.out.println("NamingException: "+ne.getMessage());
         }
       }

       public void destroy () {
         try {
           if (rs != null)
             rs.close();
           if (ps != null)
             ps.close();
           if (conn != null)
             conn.close();
           if (ctx != null)
             ctx.close();
         }
         catch (SQLException se) {
           System.out.println("SQLException: "+se.getMessage());
         }
         catch (NamingException ne) {
           System.out.println("NamingException: "+ne.getMessage());
         }
       }

       public void doPost(HttpServletRequest req, HttpServletResponse resp){
         try {
           String country_name = req.getParameter("country_name");
           resp.setContentType("text/html");
           PrintWriter writer = resp.getWriter();
           writer.println("<html><body>");
           writer.println("<p>Country: "+country_name+"</p>");
           ps.setString(1, country_name);
           rs = ps.executeQuery();
           if (!rs.next()){
             writer.println("<p>Country does not exist!</p>");
           }
           else {
             rs.beforeFirst();
             while(rs.next()) {
               writer.println("<p>Name: "+rs.getString("Name")+"</p>");
               writer.println("<p>Population: "+rs.getString("Population")+"</p>");
             }
           }
           writer.println("</body></html>");
           writer.close();
         }
         catch (Exception e) {
           e.printStackTrace();
         }
       }

       public void doGet(HttpServletRequest req, HttpServletResponse resp){
         try {
           resp.setContentType("text/html");
           PrintWriter writer = resp.getWriter();
           writer.println("<html><body>");
           writer.println("<p>Hello from servlet doGet()</p>");
           writer.println("</body></html>");
           writer.close();
         }
         catch (Exception e) {
           e.printStackTrace();
         }
       }
     }

In the preceding code a basic `doGet()' method is implemented, but is
not used in the example. The code to establish the connection with the
database is as shown in the previous example, *Note
connector-j-usagenotes-glassfish-config-jsp::, and is most conveniently
located in the servlet `init()' method. The corresponding freeing of
resources is located in the destroy method. The main functionality of
the servlet is located in the `doPost()' method. If the user enters nto
the input form a country name that can be located in the database, the
population of the country is returned. The code is invoked using a POST
action associated with the input form. The form is defined in the file
`index.html':


     <html>
       <head><title>HelloWebServlet</title></head>

       <body>
         <h1>HelloWebServlet</h1>

         <p>Please enter country name:</p>

         <form action="HelloWebServlet" method="POST">
           <input type="text" name="country_name" length="50" />
           <input type="submit" value="Submit" />
         </form>

       </body>
     </html>

The XML files `web.xml' and `sun-web.xml' are as for the example in the
preceding section, *Note connector-j-usagenotes-glassfish-config-jsp::,
no additional changes are required.

Whe compiling the Java source code, you will need to specify the path
to the file `javaee.jar'. On Windows, this can be done as follows:

     shell> javac -classpath c:\glassfishv3\glassfish\lib\javaee.jar HelloWebServlet.java

Once the code is correctly located within its directory structure, and
compiled, the application can be deployed in Glassfish. This is done in
exactly the same way as described in the preceding section, *Note
connector-j-usagenotes-glassfish-config-jsp::.

Once deployed the application can be launched from within the Glassfish
Administration Console. Enter a country name such as `England', and the
application will return `Country does not exist!'. Enter `France', and
the application will return a population of 59225700.


File: manual.info,  Node: connector-j-usagenotes-troubleshooting,  Prev: connector-j-usagenotes-j2ee,  Up: connector-j-usagenotes

20.3.5.20 Connector/J: Common Problems and Solutions
....................................................

There are a few issues that seem to be commonly encountered often by
users of MySQL Connector/J. This section deals with their symptoms, and
their resolutions.

*Questions*
   * 20.3.5.3.1: When I try to connect to the database with MySQL
     Connector/J, I get the following exception:

          SQLException: Server configuration denies access to data source
          SQLState: 08001
          VendorError: 0

     What is going on? I can connect just fine with the MySQL
     command-line client.

   * 20.3.5.3.2: My application throws an SQLException 'No Suitable
     Driver'. Why is this happening?

   * 20.3.5.3.3: I'm trying to use MySQL Connector/J in an applet or
     application and I get an exception similar to:

          SQLException: Cannot connect to MySQL server on host:3306.
          Is there a MySQL server running on the machine/port you
          are trying to connect to?

          (java.security.AccessControlException)
          SQLState: 08S01
          VendorError: 0

   * 20.3.5.3.4: I have a servlet/application that works fine for a day,
     and then stops working overnight

   * 20.3.5.3.5: I'm trying to use JDBC-2.0 updatable result sets, and I
     get an exception saying my result set is not updatable.

   * 20.3.5.3.6: I cannot connect to the MySQL server using Connector/J,
     and I'm sure the connection paramters are correct.

   * 20.3.5.3.7: I am trying to connect to my MySQL server within my
     application, but I get the following error and stack trace:

          java.net.SocketException
          MESSAGE: Software caused connection abort: recv failed

          STACKTRACE:

          java.net.SocketException: Software caused connection abort: recv failed
          at java.net.SocketInputStream.socketRead0(Native Method)
          at java.net.SocketInputStream.read(Unknown Source)
          at com.mysql.jdbc.MysqlIO.readFully(MysqlIO.java:1392)
          at com.mysql.jdbc.MysqlIO.readPacket(MysqlIO.java:1414)
          at com.mysql.jdbc.MysqlIO.doHandshake(MysqlIO.java:625)
          at com.mysql.jdbc.Connection.createNewIO(Connection.java:1926)
          at com.mysql.jdbc.Connection.<init>(Connection.java:452)
          at com.mysql.jdbc.NonRegisteringDriver.connect(NonRegisteringDriver.java:411)

   * 20.3.5.3.8: My application is deployed through JBoss and I am using
     transactions to handle the statements on the MySQL database. Under
     heavy loads I am getting a error and stack trace, but these only
     occur after a fixed period of heavy activity.

   * 20.3.5.3.9: When using `gcj' an `java.io.CharConversionException'
     is raised when working with certain character sequences.

   * 20.3.5.3.10: Updating a table that contains a primary key that is
     either *Note `FLOAT': numeric-types. or compound primary key that
     uses *Note `FLOAT': numeric-types.  fails to update the table and
     raises an exception.

   * 20.3.5.3.11: You get an `ER_NET_PACKET_TOO_LARGE' exception, even
     though the binary blob size you want to insert using JDBC is
     safely below the `max_allowed_packet' size.

   * 20.3.5.3.12: What should you do if you receive error messages
     similar to the following: `Communications link failure - Last
     packet sent to the server was X ms ago'?

   * 20.3.5.3.13: Why does Connector/J not reconnect to MySQL and
     re-issue the statement after a communication failure, instead of
     throwing an Exception, even though I use the `autoReconnect'
     connection string option?

   * 20.3.5.3.14: How can I use 3-byte UTF8 with Connector/J?

   * 20.3.5.3.15: How can I use 4-byte UTF8, `utf8mb4' with Connector/J?

   * 20.3.5.3.16: Using `useServerPrepStmts=false' and certain
     character encodings can lead to corruption when inserting BLOBs.
     How can this be avoided?

*Questions and Answers* *20.3.5.3.1: ** When I try to connect to the
database with MySQL Connector/J, I get the following exception: *
     SQLException: Server configuration denies access to data source
     SQLState: 08001
     VendorError: 0
* What is going on? I can connect just fine with the MySQL command-line
client.  *

MySQL Connector/J must use TCP/IP sockets to connect to MySQL, as Java
does not support Unix Domain Sockets.  Therefore, when MySQL
Connector/J connects to MySQL, the security manager in MySQL server
will use its grant tables to determine whether the connection should be
permitted.

You must add the necessary security credentials to the MySQL server for
this to happen, using the *Note `GRANT': grant. statement to your MySQL
Server. See *Note grant::, for more information.

*Note*:

Testing your connectivity with the *Note `mysql': mysql. command-line
client will not work unless you add the `--host' flag, and use
something other than `localhost' for the host. The *Note `mysql':
mysql. command-line client will use Unix domain sockets if you use the
special host name `localhost'. If you are testing connectivity to
`localhost', use `127.0.0.1' as the host name instead.

*Warning*:

Changing privileges and permissions improperly in MySQL can potentially
cause your server installation to not have optimal security properties.

*20.3.5.3.2: ** My application throws an SQLException 'No Suitable
Driver'. Why is this happening?  *

There are three possible causes for this error:

   * The Connector/J driver is not in your `CLASSPATH', see *Note
     connector-j-installing::.

   * The format of your connection URL is incorrect, or you are
     referencing the wrong JDBC driver.

   * When using DriverManager, the `jdbc.drivers' system property has
     not been populated with the location of the Connector/J driver.

*20.3.5.3.3: ** I'm trying to use MySQL Connector/J in an applet or
application and I get an exception similar to: *
     SQLException: Cannot connect to MySQL server on host:3306.
     Is there a MySQL server running on the machine/port you
     are trying to connect to?

     (java.security.AccessControlException)
     SQLState: 08S01
     VendorError: 0

Either you're running an Applet, your MySQL server has been installed
with the "-skip-networking" option set, or your MySQL server has a
firewall sitting in front of it.

Applets can only make network connections back to the machine that runs
the web server that served the .class files for the applet. This means
that MySQL must run on the same machine (or you must have some sort of
port re-direction) for this to work. This also means that you will not
be able to test applets from your local file system, you must always
deploy them to a web server.

MySQL Connector/J can only communicate with MySQL using TCP/IP, as Java
does not support Unix domain sockets.  TCP/IP communication with MySQL
might be affected if MySQL was started with the "-skip-networking"
flag, or if it is firewalled.

If MySQL has been started with the "-skip-networking" option set (the
Debian Linux package of MySQL server does this for example), you need
to comment it out in the file /etc/mysql/my.cnf or /etc/my.cnf. Of
course your my.cnf file might also exist in the `data' directory of
your MySQL server, or anywhere else (depending on how MySQL was
compiled for your system).  Binaries created by us always look in
/etc/my.cnf and [datadir]/my.cnf. If your MySQL server has been
firewalled, you will need to have the firewall configured to allow
TCP/IP connections from the host where your Java code is running to the
MySQL server on the port that MySQL is listening to (by default, 3306).

*20.3.5.3.4: ** I have a servlet/application that works fine for a day,
and then stops working overnight *

MySQL closes connections after 8 hours of inactivity. You either need
to use a connection pool that handles stale connections or use the
"autoReconnect" parameter (see *Note
connector-j-reference-configuration-properties::).

Also, you should be catching SQLExceptions in your application and
dealing with them, rather than propagating them all the way until your
application exits, this is just good programming practice. MySQL
Connector/J will set the SQLState (see
`java.sql.SQLException.getSQLState()' in your APIDOCS) to "08S01" when
it encounters network-connectivity issues during the processing of a
query. Your application code should then attempt to re-connect to MySQL
at this point.

The following (simplistic) example shows what code that can handle
these exceptions might look like:

     public void doBusinessOp() throws SQLException {
         Connection conn = null;
         Statement stmt = null;
         ResultSet rs = null;

         //
         // How many times do you want to retry the transaction
         // (or at least _getting_ a connection)?
         //
         int retryCount = 5;

         boolean transactionCompleted = false;

         do {
             try {
                 conn = getConnection(); // assume getting this from a
                                         // javax.sql.DataSource, or the
                                         // java.sql.DriverManager

                 conn.setAutoCommit(false);

                 //
                 // Okay, at this point, the 'retry-ability' of the
                 // transaction really depends on your application logic,
                 // whether or not you're using autocommit (in this case
                 // not), and whether you're using transactional storage
                 // engines
                 //
                 // For this example, we'll assume that it's _not_ safe
                 // to retry the entire transaction, so we set retry
                 // count to 0 at this point
                 //
                 // If you were using exclusively transaction-safe tables,
                 // or your application could recover from a connection going
                 // bad in the middle of an operation, then you would not
                 // touch 'retryCount' here, and just let the loop repeat
                 // until retryCount == 0.
                 //
                 retryCount = 0;

                 stmt = conn.createStatement();

                 String query = "SELECT foo FROM bar ORDER BY baz";

                 rs = stmt.executeQuery(query);

                 while (rs.next()) {
                 }

                 rs.close();
                 rs = null;

                 stmt.close();
                 stmt = null;

                 conn.commit();
                 conn.close();
                 conn = null;

                 transactionCompleted = true;
             } catch (SQLException sqlEx) {

                 //
                 // The two SQL states that are 'retry-able' are 08S01
                 // for a communications error, and 40001 for deadlock.
                 //
                 // Only retry if the error was due to a stale connection,
                 // communications problem or deadlock
                 //

                 String sqlState = sqlEx.getSQLState();

                 if ("08S01".equals(sqlState) || "40001".equals(sqlState)) {
                     retryCount--;
                 } else {
                     retryCount = 0;
                 }
             } finally {
                 if (rs != null) {
                     try {
                         rs.close();
                     } catch (SQLException sqlEx) {
                         // You'd probably want to log this . . .
                     }
                 }

                 if (stmt != null) {
                     try {
                         stmt.close();
                     } catch (SQLException sqlEx) {
                         // You'd probably want to log this as well . . .
                     }
                 }

                 if (conn != null) {
                     try {
                         //
                         // If we got here, and conn is not null, the
                         // transaction should be rolled back, as not
                         // all work has been done

                         try {
                             conn.rollback();
                         } finally {
                             conn.close();
                         }
                     } catch (SQLException sqlEx) {
                         //
                         // If we got an exception here, something
                         // pretty serious is going on, so we better
                         // pass it up the stack, rather than just
                         // logging it. . .

                         throw sqlEx;
                     }
                 }
             }
         } while (!transactionCompleted && (retryCount > 0));
     }

*Note*:

Use of the `autoReconnect' option is not recommended because there is
no safe method of reconnecting to the MySQL server without risking some
corruption of the connection state or database state information.
Instead, you should use a connection pool which will enable your
application to connect to the MySQL server using an available
connection from the pool. The `autoReconnect' facility is deprecated,
and may be removed in a future release.

*20.3.5.3.5: ** I'm trying to use JDBC-2.0 updatable result sets, and I
get an exception saying my result set is not updatable.  *

Because MySQL does not have row identifiers, MySQL Connector/J can only
update result sets that have come from queries on tables that have at
least one primary key, the query must select every primary key and the
query can only span one table (that is, no joins). This is outlined in
the JDBC specification.

Note that this issue only occurs when using updatable result sets, and
is caused because Connector/J is unable to guarantee that it can
identify the correct rows within the result set to be updated without
having a unique reference to each row. There is no requirement to have a
unique field on a table if you are using *Note `UPDATE': update. or
*Note `DELETE': delete. statements on a table where you can
individually specify the criteria to be matched using a `WHERE' clause.

*20.3.5.3.6: ** I cannot connect to the MySQL server using Connector/J,
and I'm sure the connection paramters are correct.  *

Make sure that the `skip-networking' option has not been enabled on
your server. Connector/J must be able to communicate with your server
over TCP/IP, named sockets are not supported. Also ensure that you are
not filtering connections through a Firewall or other network security
system. For more information, see *Note can-not-connect-to-server::.

*20.3.5.3.7: ** I am trying to connect to my MySQL server within my
application, but I get the following error and stack trace: *
     java.net.SocketException
     MESSAGE: Software caused connection abort: recv failed

     STACKTRACE:

     java.net.SocketException: Software caused connection abort: recv failed
     at java.net.SocketInputStream.socketRead0(Native Method)
     at java.net.SocketInputStream.read(Unknown Source)
     at com.mysql.jdbc.MysqlIO.readFully(MysqlIO.java:1392)
     at com.mysql.jdbc.MysqlIO.readPacket(MysqlIO.java:1414)
     at com.mysql.jdbc.MysqlIO.doHandshake(MysqlIO.java:625)
     at com.mysql.jdbc.Connection.createNewIO(Connection.java:1926)
     at com.mysql.jdbc.Connection.<init>(Connection.java:452)
     at com.mysql.jdbc.NonRegisteringDriver.connect(NonRegisteringDriver.java:411)

The error probably indicates that you are using a older version of the
Connector/J JDBC driver (2.0.14 or 3.0.x) and you are trying to connect
to a MySQL server with version 4.1x or newer. The older drivers are not
compatible with 4.1 or newer of MySQL as they do not support the newer
authentication mechanisms.

It is likely that the older version of the Connector/J driver exists
within your application directory or your `CLASSPATH' includes the older
Connector/J package.

*20.3.5.3.8: ** My application is deployed through JBoss and I am using
transactions to handle the statements on the MySQL database. Under
heavy loads I am getting a error and stack trace, but these only occur
after a fixed period of heavy activity.  *

This is a JBoss, not Connector/J, issue and is connected to the use of
transactions. Under heavy loads the time taken for transactions to
complete can increase, and the error is caused because you have
exceeded the predefined timeout.

You can increase the timeout value by setting the `TransactionTimeout'
attribute to the `TransactionManagerService' within the
`/conf/jboss-service.xml' file (pre-4.0.3) or `/deploy/jta-service.xml'
for JBoss 4.0.3 or later. See TransactionTimeoute
(http://wiki.jboss.org/wiki/Wiki.jsp?page=TransactionTimeout) within
the JBoss wiki for more information.

*20.3.5.3.9: ** When using `gcj' an `java.io.CharConversionException' is
raised when working with certain character sequences.  *

This is a known issue with `gcj' which raises an exception when it
reaches an unknown character or one it cannot convert. You should add
`useJvmCharsetConverters=true' to your connection string to force
character conversion outside of the `gcj' libraries, or try a different
JDK.

*20.3.5.3.10: ** Updating a table that contains a primary key that is
either *Note `FLOAT': numeric-types. or compound primary key that uses
*Note `FLOAT': numeric-types.  fails to update the table and raises an
exception.  *

Connector/J adds conditions to the `WHERE' clause during an *Note
`UPDATE': update. to check the old values of the primary key. If there
is no match then Connector/J considers this a failure condition and
raises an exception.

The problem is that rounding differences between supplied values and
the values stored in the database may mean that the values never match,
and hence the update fails. The issue will affect all queries, not just
those from Connector/J.

To prevent this issue, use a primary key that does not use *Note
`FLOAT': numeric-types. If you have to use a floating point column in
your primary key use *Note `DOUBLE': numeric-types. or *Note `DECIMAL':
numeric-types. types in place of *Note `FLOAT': numeric-types.

*20.3.5.3.11: ** You get an `ER_NET_PACKET_TOO_LARGE' exception, even
though the binary blob size you want to insert using JDBC is safely
below the `max_allowed_packet' size.  *

This is because the `hexEscapeBlock()' method in
`com.mysql.jdbc.PreparedStatement.streamToBytes()' may almost double
the size of your data.

*20.3.5.3.12: ** What should you do if you receive error messages
similar to the following: `Communications link failure - Last packet
sent to the server was X ms ago'?  *

Generally speaking, this error suggests that the network connection has
been closed. There can be several root causes:

   * Firewalls or routers may clamp down on idle connections (the MySQL
     client/server protocol does not ping).

   * The MySQL Server may be closing idle connections which exceed the
     `wait_timeout' or `interactive_timeout' threshold.

To help troubleshoot these issues, the following tips can be used. If a
recent (5.1.13+) version of Connector/J is used, you will see an
improved level of information compared to earlier versions. Older
versions simply display the last time a packet was sent to the server,
which is frequently 0 ms ago. This is of limited use, as it may be that
a packet was just sent, while a packet from the server has not been
received for several hours.  Knowing the period of time since
Connector/J last received a packet from the server is useful
information, so if this is not displayed in your exception message, it
is recommended that you update Connector/J.

Further, if the time a packet was last sent/received exceeds the
`wait_timeout' or `interactive_timeout' threshold, this is noted in the
exception message.

Although network connections can be volatile, the following can be
helpful in avoiding problems:

   * Ensure connections are valid when used from the connection pool.
     Use a query that starts with `/* ping */' to execute a lightweight
     ping instead of full query. Note, the syntax of the ping needs to
     be exactly as specified here.

   * Minimize the duration a connection object is left idle while other
     application logic is executed.

   * Explicitly validate the connection before using it if the
     connection has been left idle for an extended period of time.

   * Ensure that `wait_timeout' and `interactive_timeout' are set
     sufficiently high.

   * Ensure that `tcpKeepalive' is enabled.

   * Ensure that any configurable firewall or router timeout settings
     allow for the maximum expected connection idle time.

*Note*:

Do not expect to be able to reuse a connection without problems, if it
has being lying idle for a period. If a connection is to be reused
after being idle for any length of time, ensure that you explicitly
test it before reusing it.

*20.3.5.3.13: ** Why does Connector/J not reconnect to MySQL and
re-issue the statement after a communication failure, instead of
throwing an Exception, even though I use the `autoReconnect' connection
string option?  *

There are several reasons for this. The first is transactional
integrity. The MySQL Reference Manual states that `there is no safe
method of reconnecting to the MySQL server without risking some
corruption of the connection state or database state information'.
Consider the following series of statements for example:


     conn.createStatement().execute(
       "UPDATE checking_account SET balance = balance - 1000.00 WHERE customer='Smith'");
     conn.createStatement().execute(
       "UPDATE savings_account SET balance = balance + 1000.00 WHERE customer='Smith'");
     conn.commit();

Consider the case where the connection to the server fails after the
`UPDATE' to `checking_account'. If no exception is thrown, and the
application never learns about the problem, it will continue executing.
However, the server did not commit the first transaction in this case,
so that will get rolled back. But execution continues with the next
transaction, and increases the `savings_account' balance by 1000. The
application did not receive an exception, so it continued regardless,
eventually committing the second transaction, as the commit only
applies to the changes made in the new connection. Rather than a
transfer taking place, a deposit was made in this example.

Note that running with `auto-commit' enabled does not solve this
problem. When Connector/J encounters a communication problem, there is
no means to determine whether the server processed the currently
executing statement or not. The following theoretical states are
equally possible:

   * The server never received the statement, and therefore no related
     processing occurred on the server.

   * The server received the statement, executed it in full, but the
     response was not received by the client.

If you are running with `auto-commit' enabled, it is not possible to
guarantee the state of data on the server when a communication
exception is encountered. The statement may have reached the server, or
it may not. All you know is that communication failed at some point,
before the client received confirmation (or data) from the server. This
does not only affect `auto-commit' statements though. If the
communication problem occurred during `Connection.commit()', the
question arises of whether the transaction was committed on the server
before the communication failed, or whether the server received the
commit request at all.

The second reason for the generation of exceptions is that
transaction-scoped contextual data may be vulnerable, for example:

   * Temporary tables

   * User-defined variables

   * Server-side prepared statements

These items are lost when a connection fails, and if the connection
silently reconnects without generating an exception, this could be
detrimental to the correct execution of your application.

In summary, communication errors generate conditions that may well be
unsafe for Connector/J to simply ignore by silently reconnecting. It is
necessary for the application to be notified. It is then for the
application developer to decide how to proceed in the event of
connection errors and failures.

*20.3.5.3.14: ** How can I use 3-byte UTF8 with Connector/J?  *

To use 3-byte UTF8 with Connector/J set `characterEncoding=utf8' and set
`useUnicode=true' in the connection string.

*20.3.5.3.15: ** How can I use 4-byte UTF8, `utf8mb4' with Connector/J?
*

To use 4-byte UTF8 with Connector/J configure the MySQL server with
`character_set_server=utf8mb4'.  Connector/J will then use that setting
as long as `characterEncoding' has not been set in the connection
string. This is equivalent to autodetection of the character set.

*20.3.5.3.16: ** Using `useServerPrepStmts=false' and certain character
encodings can lead to corruption when inserting BLOBs. How can this be
avoided?  *

When using certain character encodings, such as SJIS, CP932, and BIG5,
it is possible that BLOB data contains characters that can be
interpreted as control characters, for example, backslash, '\'. This
can lead to corrupted data when inserting BLOBs into the database.
There are two things that need to be done to avoid this:

  1. Set the connection string option `useServerPrepStmts' to `true'.

  2. Set `SQL_MODE' to `NO_BACKSLASH_ESCAPES'.


File: manual.info,  Node: connector-j-support,  Prev: connector-j-usagenotes,  Up: connector-j

20.3.6 Connector/J Support
--------------------------

* Menu:

* connector-j-support-community::  Connector/J Community Support
* connector-j-support-bug-report::  How to Report Connector/J Bugs or Problems
* connector-j-support-changelog::  Connector/J Change History


File: manual.info,  Node: connector-j-support-community,  Next: connector-j-support-bug-report,  Prev: connector-j-support,  Up: connector-j-support

20.3.6.1 Connector/J Community Support
......................................

Oracle provides assistance to the user community by means of its
mailing lists. For Connector/J related issues, you can get help from
experienced users by using the MySQL and Java mailing list.  Archives
and subscription information is available online at
`http://lists.mysql.com/java'.

For information about subscribing to MySQL mailing lists or to browse
list archives, visit `http://lists.mysql.com/'. See *Note
mailing-lists::.

Community support from experienced users is also available through the
JDBC Forum (http://forums.mysql.com/list.php?39). You may also find
help from other users in the other MySQL Forums, located at
`http://forums.mysql.com'. See *Note forums::.


File: manual.info,  Node: connector-j-support-bug-report,  Next: connector-j-support-changelog,  Prev: connector-j-support-community,  Up: connector-j-support

20.3.6.2 How to Report Connector/J Bugs or Problems
...................................................

The normal place to report bugs is `http://bugs.mysql.com/', which is
the address for our bugs database. This database is public, and can be
browsed and searched by anyone. If you log in to the system, you will
also be able to enter new reports.

If you have found a sensitive security bug in MySQL, you can send email
to <security@mysql.com>.

Writing a good bug report takes patience, but doing it right the first
time saves time both for us and for yourself. A good bug report,
containing a full test case for the bug, makes it very likely that we
will fix the bug in the next release.

This section will help you write your report correctly so that you do
not waste your time doing things that may not help us much or at all.

If you have a repeatable bug report, please report it to the bugs
database at `http://bugs.mysql.com/'. Any bug that we are able to
repeat has a high chance of being fixed in the next MySQL release.

To report other problems, you can use one of the MySQL mailing lists.

Remember that it is possible for us to respond to a message containing
too much information, but not to one containing too little. People
often omit facts because they think they know the cause of a problem
and assume that some details do not matter.

A good principle is this: If you are in doubt about stating something,
state it. It is faster and less troublesome to write a couple more
lines in your report than to wait longer for the answer if we must ask
you to provide information that was missing from the initial report.

The most common errors made in bug reports are (a) not including the
version number of Connector/J or MySQL used, and (b) not fully
describing the platform on which Connector/J is installed (including
the JVM version, and the platform type and version number that MySQL
itself is installed on).

This is highly relevant information, and in 99 cases out of 100, the
bug report is useless without it. Very often we get questions like,
`Why doesn't this work for me?' Then we find that the feature requested
wasn't implemented in that MySQL version, or that a bug described in a
report has already been fixed in newer MySQL versions.

Sometimes the error is platform-dependent; in such cases, it is next to
impossible for us to fix anything without knowing the operating system
and the version number of the platform.

If at all possible, you should create a repeatable, standalone testcase
that doesn't involve any third-party classes.

To streamline this process, we ship a base class for testcases with
Connector/J, named 'com.mysql.jdbc.util.BaseBugReport'. To create a
testcase for Connector/J using this class, create your own class that
inherits from com.mysql.jdbc.util.BaseBugReport and override the
methods `setUp()', `tearDown()' and `runTest()'.

In the `setUp()' method, create code that creates your tables, and
populates them with any data needed to demonstrate the bug.

In the `runTest()' method, create code that demonstrates the bug using
the tables and data you created in the `setUp' method.

In the `tearDown()' method, drop any tables you created in the
`setUp()' method.

In any of the above three methods, you should use one of the variants
of the `getConnection()' method to create a JDBC connection to MySQL:

   * `getConnection()' - Provides a connection to the JDBC URL
     specified in `getUrl()'.  If a connection already exists, that
     connection is returned, otherwise a new connection is created.

   * `getNewConnection()' - Use this if you need to get a new
     connection for your bug report (that is, there is more than one
     connection involved).

   * `getConnection(String url)' - Returns a connection using the given
     URL.

   * `getConnection(String url, Properties props)' - Returns a
     connection using the given URL and properties.

If you need to use a JDBC URL that is different from
'jdbc:mysql:///test', override the method `getUrl()' as well.

Use the `assertTrue(boolean expression)' and `assertTrue(String
failureMessage, boolean expression)' methods to create conditions that
must be met in your testcase demonstrating the behavior you are
expecting (vs. the behavior you are observing, which is why you are
most likely filing a bug report).

Finally, create a `main()' method that creates a new instance of your
testcase, and calls the `run' method:

     public static void main(String[] args) throws Exception {
           new MyBugReport().run();
      }

Once you have finished your testcase, and have verified that it
demonstrates the bug you are reporting, upload it with your bug report
to `http://bugs.mysql.com/'.


File: manual.info,  Node: connector-j-support-changelog,  Prev: connector-j-support-bug-report,  Up: connector-j-support

20.3.6.3 Connector/J Change History
...................................

The Connector/J Change History (Changelog) is located with the main
Changelog for MySQL. See *Note cj-news::.


File: manual.info,  Node: connector-mxj,  Next: connector-c,  Prev: connector-j,  Up: connectors-apis

20.4 MySQL Connector/MXJ
========================

* Menu:

* connector-mxj-overview::       Connector/MXJ Overview
* connector-mxj-versions::       Connector/MXJ Versions
* connector-mxj-install::        Connector/MXJ Installation
* connector-mxj-configuration::  Connector/MXJ Configuration
* connector-mxj-ref::            Connector/MXJ Reference
* connector-mxj-usagenotes::     Connector/MXJ Notes and Tips
* connector-mxj-samples::        Connector/MXJ Samples
* connector-mxj-support::        Connector/MXJ Support

MySQL Connector/MXJ is a Java Utility package for deploying and
managing a MySQL database. Deploying and using MySQL can be as easy as
adding another parameter to the JDBC connection url, which will result
in the database being started when the first connection is made. This
makes it easy for Java developers to deploy applications which require
a database by reducing installation barriers for their end-users.

MySQL Connector/MXJ makes the MySQL database appear to be a java-based
component. It does this by determining what platform the system is
running on, selecting the appropriate binary, and launching the
executable. It will also optionally deploy an initial database, with
any specified parameters.

Included are instructions for use with a JDBC driver and deploying as a
JMX MBean to JBoss.

You can download sources and binaries from:
`http://dev.mysql.com/downloads/connector/mxj/'

This a beta release and feedback is welcome and encouraged.

Please send questions or comments to the MySQL and Java mailing list
(http://lists.mysql.com/java).


File: manual.info,  Node: connector-mxj-overview,  Next: connector-mxj-versions,  Prev: connector-mxj,  Up: connector-mxj

20.4.1 Connector/MXJ Overview
-----------------------------

Connector/MXJ consists of a Java class, a copy of the `mysqld' binary
for a specific list of platforms, and associated files and support
utilities. The Java class controls the initialization of an instance of
the embedded `mysqld' binary, and the ongoing management of the
`mysqld' process. The entire sequence and management can be controlled
entirely from within Java using the Connector/MXJ Java classes. You can
see an overview of the contents of the Connector/MXJ package in the
figure below.

Connector/MXJ Overview

It is important to note that Connector/MXJ is not an embedded version
of MySQL, or a version of MySQL written as part of a Java class.
Connector/MXJ works through the use of an embedded, compiled binary of
`mysqld' as would normally be used when deploying a standard MySQL
installation.

It is the Connector/MXJ wrapper, support classes and tools, that enable
Connector/MXJ to appear as a MySQL instance.

When Connector/MXJ is initialized, the corresponding `mysqld' binary
for the current platform is extracted, along with a pre-configured data
directed. Both are contained within the Connector/MXJ JAR file. The
`mysqld' instance is then started, with any additional options as
specified during the initialization, and the MySQL database becomes
accessible.

Because Connector/MXJ works in combination with Connector/J, you can
access and integrate with the MySQL instance through a JDBC connection.
When you have finished with the server, the instance is terminated,
and, by default, any data created during the session is retained within
the temporary directory created when the instance was started.

Connector/MXJ and the embedded `mysqld' instance can be deployed in a
number of environments where relying on an existing database, or
installing a MySQL instance would be impossible, including CD-ROM
embedded database applications and temporary database requirements
within a Java-based application environment.


File: manual.info,  Node: connector-mxj-versions,  Next: connector-mxj-install,  Prev: connector-mxj-overview,  Up: connector-mxj

20.4.2 Connector/MXJ Versions
-----------------------------

Connector/MXJ 5.x, currently in beta status, includes `mysqld' version
5.x and includes binaries for Linux x86, Mac OS X PPC, Windows
XP/NT/2000 x86 and Solaris SPARC.  Connector/MXJ 5.x requires the
Connector/J 5.x package.

A summary of the different MySQL versions supplied with each
Connector/MXJ release are shown in the table.

Connector/MXJ Version                MySQL Version(s)
5.0.11                               5.1.40
5.0.9                                5.0.51a (CS), 5.0.54 (ES)
5.0.8                                5.0.45 (CS), 5.0.46 (ES)
5.0.7                                5.0.41 (CS), 5.0.42 (ES)
5.0.6                                5.0.37 (CS), 5.0.40 (ES)
5.0.5                                5.0.37 (CS), 5.0.36 (ES)
5.0.4                                5.0.27 (CS), 5.0.32 (ES)
5.0.3                                5.0.22
5.0.2                                5.0.19

This guide provides information on the Connector/MXJ 5.x release.  For
information on using the older releases, please see the documentation
included with the appropriate distribution.


File: manual.info,  Node: connector-mxj-install,  Next: connector-mxj-configuration,  Prev: connector-mxj-versions,  Up: connector-mxj

20.4.3 Connector/MXJ Installation
---------------------------------

* Menu:

* connector-mxj-install-platforms::  Supported Platforms
* connector-mxj-install-base::   Connector/MXJ Base Installation
* connector-mxj-install-quickstart::  Connector/MXJ Quick Start Guide
* connector-mxj-install-class::  Deploying Connector/MXJ using Driver Launch
* connector-mxj-install-jboss::  Deploying Connector/MXJ within JBoss
* connector-mxj-installation-test::  Verifying Installation using JUnit

Connector/MXJ does not have a installation application or process, but
there are some steps you can follow to make the installation and
deployment of Connector/MXJ easier.

Before you start, there are some baseline requirements for

   * Java Runtime Environment (v1.4.0 or newer) if you are only going
     to deploy the package.

   * Java Development Kit (v1.4.0 or newer) if you intend to build
     Connector/MXJ from source.

   * Connector/J 5.0 or newer.

Depending on your target installation/deployment environment you may
also require:

   * JBoss - 4.0rc1 or newer

   * Apache Tomcat - 5.0 or newer

   * Sun's JMX reference implementation version 1.2.1 (from
     `http://java.sun.com/products/JavaManagement/')


File: manual.info,  Node: connector-mxj-install-platforms,  Next: connector-mxj-install-base,  Prev: connector-mxj-install,  Up: connector-mxj-install

20.4.3.1 Supported Platforms
............................

Connector/MXJ is compatible with any platform supporting Java and
MySQL. By default, Connector/MXJ incorporates the `mysqld' binary for a
select number of platforms which differs by version. The following
platforms have been tested and working as deployment platforms. Support
for all the platforms listed below is not included by default.

   * Linux (i386)

   * FreeBSD (i386)

   * Windows NT (x86), Windows 2000 (x86), Windows XP (x86), Windows
     Vista (x86)

   * Solaris 8, SPARC 32-bit (compatible with Solaris 8, Solaris 9 and
     Solaris 10 on SPARC 32-bit and 64-bit platforms)

   * Mac OS X (PowerPC and Intel)

The Connector/MXJ 5.0.8 release includes *Note `mysqld': mysqld.
binaries for the following platforms:

   * Linux (i386)

   * Windows (x86), compatible with Windows NT, Windows 2000, Windows
     XP , Windows Vista

   * Solaris 8, SPARC 32-bit (compatible with Solaris 8, Solaris 9 and
     Solaris 10 on SPARC 32-bit and 64-bit platforms)

   * Mac OS X (PowerPC and Intel)

For more information on packaging your own Connector/MXJ with the
platforms you require, see *Note connector-mxj-usagenotes-packaging::


File: manual.info,  Node: connector-mxj-install-base,  Next: connector-mxj-install-quickstart,  Prev: connector-mxj-install-platforms,  Up: connector-mxj-install

20.4.3.2 Connector/MXJ Base Installation
........................................

Because there is no formal installation process, the method,
installation directory, and access methods you use for Connector/MXJ
are entirely up to your individual requirements.

To perform a basic installation, choose a target directory for the
files included in the Connector/MXJ package. On Unix/Linux systems, you
might use a directory such as `/usr/local/connector-mxj'. On Windows,
you might install the files in the base directory, `C:\Connector-MXJ',
or within the `Program Files' directory.

To install the files, for a Connector/MXJ 5.0.4 installation:

  1. Download the Connector/MXJ package, either in Tar/Gzip format
     (ideal for Unix/Linux systems) or Zip format (Windows).

  2. Extract the files from the package. This will create a directory
     `mysql-connector-mxj-gpl-[ver]'. Copy and optionally rename this
     directory to your desired location.

  3. For best results, you should update your global `CLASSPATH'
     variable with the location of the required `jar' files.

     Within Unix/Linux you can do this globally by editing the global
     shell profile, or on a user by user basis by editing their
     individual shell profile.

     On Windows 2000, Windows NT and Windows XP, you can edit the
     global `CLASSPATH' by editing the `Environment Variables'
     configured through the `System' control panel.

For Connector/MXJ 5.0.6 and later you need the following JAR files in
your `CLASSPATH':

   * `mysql-connector-mxj-gpl-[ver].jar': contains the main
     Connector/MXJ classes.

   * `mysql-connector-mxj-gpl-[ver]-db-files.jar': contains the
     embedded `mysqld' and database files.

   * `aspectjrt.jar': the AspectJ runtime library, located in
     `lib/aspectjrt.jar' in the Connector/MXJ package.

   * `mysql-connector-java-[ver]-bin.jar': Connector/J, see *Note
     connector-j::.

For Connector/MXJ 5.0.4 and later you need the following JAR files in
your `CLASSPATH':

   * `connector-mxj.jar': contains the main Connector/MXJ classes.

   * `connector-mxj-db-files.jar': contains the embedded `mysqld' and
     database files.

   * `aspectjrt.jar': the AspectJ runtime library, located in
     `lib/aspectjrt.jar' in the Connector/MXJ package.

   * `mysql-connector-mxj-gpl-[ver].jar': Connector/J, see *Note
     connector-j::.

For Connector/MXJ 5.0.3 and earlier, you need the following JAR files:

   * `connector-mxj.jar'

   * `aspectjrt.jar': the AspectJ runtime library, located in
     `lib/aspectjrt.jar' in the Connector/MXJ package.

   * `mysql-connector-mxj-gpl-[ver].jar': Connector/J, see *Note
     connector-j::.


File: manual.info,  Node: connector-mxj-install-quickstart,  Next: connector-mxj-install-class,  Prev: connector-mxj-install-base,  Up: connector-mxj-install

20.4.3.3 Connector/MXJ Quick Start Guide
........................................

Once you have extracted the Connector/MXJ and Connector/J components
you can run one of the sample applications that initiates a MySQL
instance. You can test the installation by running the
`ConnectorMXJUrlTestExample':

     shell> java ConnectorMXJUrlTestExample
     jdbc:mysql:mxj://localhost:3336/our_test_app?server.basedir»
         =/var/tmp/test-mxj&createDatabaseIfNotExist=true&server.initialize-user=true
     [/var/tmp/test-mxj/bin/mysqld][--no-defaults][--port=3336][--socket=mysql.sock]»
         [--basedir=/var/tmp/test-mxj][--datadir=/var/tmp/test-mxj/data]»
         [--pid-file=/var/tmp/test-mxj/data/MysqldResource.pid]
     [MysqldResource] launching mysqld (driver_launched_mysqld_1)
     InnoDB: The first specified data file ./ibdata1 did not exist:
     InnoDB: a new database to be created!
     080220  9:40:20  InnoDB: Setting file ./ibdata1 size to 10 MB
     InnoDB: Database physically writes the file full: wait...
     080220  9:40:20  InnoDB: Log file ./ib_logfile0 did not exist: new to be created
     InnoDB: Setting log file ./ib_logfile0 size to 5 MB
     InnoDB: Database physically writes the file full: wait...
     080220  9:40:20  InnoDB: Log file ./ib_logfile1 did not exist: new to be created
     InnoDB: Setting log file ./ib_logfile1 size to 5 MB
     InnoDB: Database physically writes the file full: wait...
     InnoDB: Doublewrite buffer not found: creating new
     InnoDB: Doublewrite buffer created
     InnoDB: Creating foreign key constraint system tables
     InnoDB: Foreign key constraint system tables created
     080220  9:40:21  InnoDB: Started; log sequence number 0 0
     080220  9:40:21 [Note] /var/tmp/test-mxj/bin/mysqld: ready for connections.
     Version: '5.0.51a'  socket: 'mysql.sock'  port: 3336  MySQL Community Server (GPL)
     [MysqldResource] mysqld running as process: 2238
     ------------------------
     SELECT VERSION()
     ------------------------
     5.0.51a
     ------------------------
     [MysqldResource] stopping mysqld (process: 2238)
     080220  9:40:27 [Note] /var/tmp/test-mxj/bin/mysqld: Normal shutdown

     080220  9:40:27  InnoDB: Starting shutdown...
     080220  9:40:29  InnoDB: Shutdown completed; log sequence number 0 43655
     080220  9:40:29 [Note] /var/tmp/test-mxj/bin/mysqld: Shutdown complete

     [MysqldResource] shutdown complete

The above output shows an instance of MySQL starting, the necessary
files being created (log files, InnoDB data files) and the MySQL
database entering the running state. The instance is then shutdown by
Connector/MXJ before the example terminates.

*Warning*:

You should avoid running your Connector/MXJ application as the `root'
user, because this will cause the *Note `mysqld': mysqld. to also be
executed with root privileges. For more information, see *Note
changing-mysql-user::.


File: manual.info,  Node: connector-mxj-install-class,  Next: connector-mxj-install-jboss,  Prev: connector-mxj-install-quickstart,  Up: connector-mxj-install

20.4.3.4 Deploying Connector/MXJ using Driver Launch
....................................................

Connector/MXJ and Connector/J work together to enable you to launch an
instance of the `mysqld' server through the use of a keyword in the
JDBC connection string.  Deploying Connector/MXJ within a Java
application can be automated through this method, making the deployment
of Connector/MXJ a simple process:

  1. Download and unzip Connector/MXJ. Add
     `mysql-connector-mxj-gpl-[ver].jar' to the `CLASSPATH'.

     If you are using Connector/MXJ v5.0.4 or later, also add the
     `mysql-connector-mxj-gpl-[ver]-db-files.jar' file to your
     `CLASSPATH'.

  2. To the JDBC connection string, embed the `mxj' keyword, for
     example: `jdbc:mysql:mxj://localhost:PORT/DBNAME'.

For more details, see *Note connector-mxj-configuration::.


File: manual.info,  Node: connector-mxj-install-jboss,  Next: connector-mxj-installation-test,  Prev: connector-mxj-install-class,  Up: connector-mxj-install

20.4.3.5 Deploying Connector/MXJ within JBoss
.............................................

For deployment of Connector/MXJ within a JBoss environment, you must
configure the JBoss environment to use the Connector/MXJ component
within the JDBC parameters:

  1. Download Connector/MXJ and copy the
     `mysql-connector-mxj-gpl-[ver].jar' file to the
     `$JBOSS_HOME/server/default/lib' directory.

     If you are using Connector/MXJ v5.0.4 or later, also copy the
     `mysql-connector-mxj-gpl-[ver]-db-files.jar' file to
     `$JBOSS_HOME/server/default/lib'.

  2. Download Connector/J and copy the
     `mysql-connector-java-5.1.5-bin.jar' file to the
     `$JBOSS_HOME/server/default/lib' directory.

  3. Create an MBean service xml file in the
     `$JBOSS_HOME/server/default/deploy' directory with any attributes
     set, for instance the `datadir' and `autostart'.

  4. Set the JDBC parameters of your web application to use:

          String driver = "com.mysql.jdbc.Driver";
          String url = "jdbc:mysql:///test?propertiesTransform="+
                       "com.mysql.management.jmx.ConnectorMXJPropertiesTransform";
          String user = "root";
          String password = "";
          Class.forName(driver);
          Connection conn = DriverManager.getConnection(url, user, password);

You might create a separate users and database table spaces for each
application, rather than using "root and test".

We highly suggest having a routine backup procedure for backing up the
database files in the `datadir'.


File: manual.info,  Node: connector-mxj-installation-test,  Prev: connector-mxj-install-jboss,  Up: connector-mxj-install

20.4.3.6 Verifying Installation using JUnit
...........................................

* Menu:

* connector-mxj-installation-test-requirements::  JUnit Test Requirements
* connector-mxj-installation-test-running::  Running the JUnit Tests

The best way to ensure that your platform is supported is to run the
JUnit tests. These will test the Connector/MXJ classes and the
associated components.


File: manual.info,  Node: connector-mxj-installation-test-requirements,  Next: connector-mxj-installation-test-running,  Prev: connector-mxj-installation-test,  Up: connector-mxj-installation-test

20.4.3.7 JUnit Test Requirements
................................

The first thing to do is make sure that the components will work on the
platform. The MysqldResource class is really a wrapper for a native
version of MySQL, so not all platforms are supported. At the time of
this writing, Linux on the i386 architecture has been tested and seems
to work quite well, as does OS X v10.3. There has been limited testing
on Windows and Solaris.

Requirements:

  1. JDK-1.4 or newer (or the JRE if you aren't going to be compiling
     the source or JSPs).

  2. MySQL Connector/J version 5.0 or newer (from
     `http://dev.mysql.com/downloads/connector/j/') installed and
     available using your CLASSPATH.

  3. The `javax.management' classes for JMX version 1.2.1, these are
     present in the following application servers:

        * JBoss - 4.0rc1 or newer.

        * Apache Tomcat - 5.0 or newer.

        * Sun's JMX reference implementation version 1.2.1 (from
          `http://java.sun.com/products/JavaManagement/').

  4. JUnit 3.8.1 (from `http://www.junit.org/').

If building from source, All of the requirements from above, plus:

  1. Ant version 1.5 or newer (download from `http://ant.apache.org/').


File: manual.info,  Node: connector-mxj-installation-test-running,  Prev: connector-mxj-installation-test-requirements,  Up: connector-mxj-installation-test

20.4.3.8 Running the JUnit Tests
................................

  1. The tests attempt to launch MySQL on the port 3336. If you have a
     MySQL running, it may conflict, but this isn't very likely because
     the default port for MySQL is 3306.  However, You may set the
     "c-mxj_test_port" Java property to a port of your choosing.
     Alternatively, you may wish to start by shutting down any
     instances of MySQL you have running on the target machine.

     The tests suppress output to the console by default. For verbose
     output, you may set the "c-mxj_test_silent" Java property to
     "false".

  2. To run the JUnit test suite, the $CLASSPATH must include the
     following:

        * JUnit

        * JMX

        * Connector/J

        * MySQL Connector/MXJ

  3. If `connector-mxj.jar' is not present in your download, unzip
     MySQL Connector/MXJ source archive.

          cd mysqldjmx
          ant dist

     Then add `$TEMP/cmxj/stage/connector-mxj/connector-mxj.jar' to the
     CLASSPATH.

  4. If you have `junit', execute the unit tests. From the command
     line, type:

          java com.mysql.management.AllTestsSuite

     The output should look something like this:

          .........................................
          .........................................
          ..........
          Time: 259.438

          OK (101 tests)

     Note that the tests are a bit slow near the end, so please be
     patient.


File: manual.info,  Node: connector-mxj-configuration,  Next: connector-mxj-ref,  Prev: connector-mxj-install,  Up: connector-mxj

20.4.4 Connector/MXJ Configuration
----------------------------------

* Menu:

* connector-mxj-configuration-driver-launched::  Running as part of the JDBC Driver
* connector-mxj-configuration-java-object::  Running within a Java Object
* connector-mxj-configuration-options::  Setting server options


File: manual.info,  Node: connector-mxj-configuration-driver-launched,  Next: connector-mxj-configuration-java-object,  Prev: connector-mxj-configuration,  Up: connector-mxj-configuration

20.4.4.1 Running as part of the JDBC Driver
...........................................

A feature of the MySQL Connector/J JDBC driver is the ability to
specify a connection to an embedded Connector/MXJ instance through the
use of the mxj keyword in the JDBC connection string.

In the following example, we have a program which creates a connection,
executes a query, and prints the result to the System.out. The MySQL
database will be deployed and started as part of the connection
process, and shutdown as part of the finally block.

You can find this file in the Connector/MXJ package as
`src/ConnectorMXJUrlTestExample.java'.

     import java.io.File;
     import java.sql.Connection;
     import java.sql.DriverManager;

     import com.mysql.management.driverlaunched.ServerLauncherSocketFactory;
     import com.mysql.management.util.QueryUtil;

     public class ConnectorMXJUrlTestExample {
       public static String DRIVER = "com.mysql.jdbc.Driver";

       public static String JAVA_IO_TMPDIR = "java.io.tmpdir";

       public static void main(String[] args) throws Exception {
         File ourAppDir = new File(System.getProperty(JAVA_IO_TMPDIR));
         File databaseDir = new File(ourAppDir, "test-mxj");
         int port = Integer.parseInt(System.getProperty("c-mxj_test_port", "3336"));
         String dbName = "our_test_app";

         String url = "jdbc:mysql:mxj://localhost:" + port + "/" + dbName //
           + "?" + "server.basedir=" + databaseDir //
           + "&" + "createDatabaseIfNotExist=true"//
           + "&" + "server.initialize-user=true" //
         ;

         System.out.println(url);

         String userName = "alice";
         String password = "q93uti0opwhkd";

         Class.forName(DRIVER);
         Connection conn = null;
         try {
           conn = DriverManager.getConnection(url, userName, password);
           String sql = "SELECT VERSION()";
           String queryForString = new QueryUtil(conn).queryForString(sql);

           System.out.println("------------------------");
           System.out.println(sql);
           System.out.println("------------------------");
           System.out.println(queryForString);
           System.out.println("------------------------");
           System.out.flush();
           Thread.sleep(100); // wait for System.out to finish flush
         } finally {
           try {
             if (conn != null)
                conn.close();
           } catch (Exception e) {
             e.printStackTrace();
           }

           ServerLauncherSocketFactory.shutdown(databaseDir, null);
         }
       }
     }

To run the above program, be sure to have connector-mxj.jar and
Connector/J in the CLASSPATH. Then type:

     java ConnectorMXJUrlTestExample


File: manual.info,  Node: connector-mxj-configuration-java-object,  Next: connector-mxj-configuration-options,  Prev: connector-mxj-configuration-driver-launched,  Up: connector-mxj-configuration

20.4.4.2 Running within a Java Object
.....................................

If you have a java application and wish to `embed' a MySQL database,
make use of the `com.mysql.management.MysqldResource' class directly.
This class may be instantiated with the default (no argument)
constructor, or by passing in a java.io.File object representing the
directory you wish the server to be "unzipped" into. It may also be
instantiated with printstreams for "stdout" and "stderr" for logging.

Once instantiated, a `java.util.Map', the object will be able to
provide a `java.util.Map' of server options appropriate for the
platform and version of MySQL which you will be using.

The MysqldResource enables you to "start" MySQL with a `java.util.Map'
of server options which you provide, as well as "shutdown" the
database. The following example shows a simplistic way to embed MySQL
in an application using plain java objects.

You can find this file in the Connector/MXJ package as
`src/ConnectorMXJObjectTestExample.java'.

     import java.io.File;
     import java.sql.Connection;
     import java.sql.DriverManager;
     import java.util.HashMap;
     import java.util.Map;

     import com.mysql.management.MysqldResource;
     import com.mysql.management.MysqldResourceI;
     import com.mysql.management.util.QueryUtil;

     public class ConnectorMXJObjectTestExample {
         public static final String DRIVER = "com.mysql.jdbc.Driver";

         public static final String JAVA_IO_TMPDIR = "java.io.tmpdir";

         public static void main(String[] args) throws Exception {
             File ourAppDir = new File(System.getProperty(JAVA_IO_TMPDIR));
             File databaseDir = new File(ourAppDir, "mysql-mxj");
             int port = Integer.parseInt(System.getProperty("c-mxj_test_port",
                     "3336"));
             String userName = "alice";
             String password = "q93uti0opwhkd";

             MysqldResource mysqldResource = startDatabase(databaseDir, port,
                     userName, password);

             Class.forName(DRIVER);
             Connection conn = null;
             try {
                 String dbName = "our_test_app";
                 String url = "jdbc:mysql://localhost:" + port + "/" + dbName //
                         + "?" + "createDatabaseIfNotExist=true"//
                 ;
                 conn = DriverManager.getConnection(url, userName, password);
                 String sql = "SELECT VERSION()";
                 String queryForString = new QueryUtil(conn).queryForString(sql);

                 System.out.println("------------------------");
                 System.out.println(sql);
                 System.out.println("------------------------");
                 System.out.println(queryForString);
                 System.out.println("------------------------");
                 System.out.flush();
                 Thread.sleep(100); // wait for System.out to finish flush
             } finally {
                 try {
                     if (conn != null) {
                         conn.close();
                     }
                 } catch (Exception e) {
                     e.printStackTrace();
                 }
                 try {
                     mysqldResource.shutdown();
                 } catch (Exception e) {
                     e.printStackTrace();
                 }
             }
         }

         public static MysqldResource startDatabase(File databaseDir, int port,
                 String userName, String password) {
             MysqldResource mysqldResource = new MysqldResource(databaseDir);

             Map database_options = new HashMap();
             database_options.put(MysqldResourceI.PORT, Integer.toString(port));
             database_options.put(MysqldResourceI.INITIALIZE_USER, "true");
             database_options.put(MysqldResourceI.INITIALIZE_USER_NAME, userName);
             database_options.put(MysqldResourceI.INITIALIZE_PASSWORD, password);

             mysqldResource.start("test-mysqld-thread", database_options);

             if (!mysqldResource.isRunning()) {
                 throw new RuntimeException("MySQL did not start.");
             }

             System.out.println("MySQL is running.");

             return mysqldResource;
         }
     }


File: manual.info,  Node: connector-mxj-configuration-options,  Prev: connector-mxj-configuration-java-object,  Up: connector-mxj-configuration

20.4.4.3 Setting server options
...............................

Of course there are many options we may wish to set for a MySQL
database. These options may be specified as part of the JDBC connection
string simply by prefixing each server option with `server.'. In the
following example we set two driver parameters and two server
parameters:

             String url = "jdbc:mysql://" + hostColonPort + "/"
                     + "?"
                     + "cacheServerConfiguration=true"
                     + "&"
                     + "useLocalSessionState=true"
                     + "&"
                     + "server.basedir=/opt/myapp/db"
                     + "&"
                     + "server.datadir=/mnt/bigdisk/myapp/data";

Starting with Connector/MXJ 5.0.6 you can use the `initialize-user'
property to a connection string. If set to true, the default anonymous
and root users will be removed and the user/password combination from
the connection URL will be used to create a new user. For example:

             String url = "jdbc:mysql:mxj://localhost:" + port
             + "/alice_db"
             + "?server.datadir=" + dataDir.getPath()
             + "&server.initialize-user=true"
             + "&createDatabaseIfNotExist=true"
             ;


File: manual.info,  Node: connector-mxj-ref,  Next: connector-mxj-usagenotes,  Prev: connector-mxj-configuration,  Up: connector-mxj

20.4.5 Connector/MXJ Reference
------------------------------

* Menu:

* connector-mxj-ref-mysqldresource-ctor::  MysqldResource Constructors
* connector-mxj-ref-mysqldresource-methods::  MysqldResource Methods

The following sections include detailed information on the different
API interfaces to Connector/MXJ.


File: manual.info,  Node: connector-mxj-ref-mysqldresource-ctor,  Next: connector-mxj-ref-mysqldresource-methods,  Prev: connector-mxj-ref,  Up: connector-mxj-ref

20.4.5.1 MysqldResource Constructors
....................................

The `MysqldResource' class supports three different constructor forms:

   * `public MysqldResource(File baseDir, File dataDir, String
     mysqlVersionString, PrintStream out, PrintStream err)'

     Enables you to set the base directory, data directory, select a
     server by its version string, standard out and standard error.

   * `public MysqldResource(File baseDir, File dataDir, String
     mysqlVersionString) '

     Enables you to set the base directory, data directory and select a
     server by its version string. Output for standard out and standard
     err are directed to System.out and System.err.

   * `public MysqldResource(File baseDir, File dataDir) '

     Enables you to set the base directory and data directory.  The
     default MySQL version is selected, and output for standard out and
     standard err are directed to System.out and System.err.

   * `public MysqldResource(File baseDir);'

     Enables the setting of the "basedir" to deploy the MySQL files to.
     Output for standard out and standard err are directed to
     System.out and System.err.

   * `public MysqldResource();'

     The basedir is defaulted to a subdirectory of the java.io.tempdir.
     Output for standard out and standard err are directed to
     System.out and System.err;


File: manual.info,  Node: connector-mxj-ref-mysqldresource-methods,  Prev: connector-mxj-ref-mysqldresource-ctor,  Up: connector-mxj-ref

20.4.5.2 MysqldResource Methods
...............................

MysqldResource API includes the following methods:

   * `void start(String threadName, Map mysqldArgs);'

     Deploys and starts MySQL. The "threadName" string is used to name
     the thread which actually performs the execution of the MySQL
     command line. The map is the set of arguments and their values to
     be passed to the command line.

   * `void shutdown(); '

     Shuts down the MySQL instance managed by the MysqldResource object.

   * ` Map getServerOptions(); '

     Returns a map of all the options and their current (or default, if
     not running) options available for the MySQL database.

   * ` boolean isRunning(); '

     Returns true if the MySQL database is running.

   * ` boolean isReadyForConnections(); '

     Returns true once the database reports that is ready for
     connections.

   * ` void setKillDelay(int millis); '

     The default `Kill Delay' is 30 seconds. This represents the amount
     of time to wait between the initial request to shutdown and
     issuing a `force kill' if the database has not shutdown by itself.

   * ` void addCompletionListenser(Runnable listener); '

     Enables applications to be notified when the server process
     completes. Each `listener' will be fired off in its own thread.

   * ` String getVersion(); '

     Returns the version of MySQL.

   * ` void setVersion(int MajorVersion, int minorVersion, int
     patchLevel); '

     The standard distribution comes with only one version of MySQL
     packaged. However, it is possible to package multiple versions,
     and specify which version to use.


File: manual.info,  Node: connector-mxj-usagenotes,  Next: connector-mxj-samples,  Prev: connector-mxj-ref,  Up: connector-mxj

20.4.6 Connector/MXJ Notes and Tips
-----------------------------------

* Menu:

* connector-mxj-usagenotes-packaging::  Creating your own Connector/MXJ Package
* connector-mxj-usagenotes-customdb::  Deploying Connector/MXJ with a pre-configured database
* connector-mxj-usagenotes-jmx-agent::  Running within a JMX Agent (custom)
* connector-mxj-usagenotes-standard-environment::  Deployment in a standard JMX Agent environment (JBoss)

This section contains notes and tips on using the Connector/MXJ
component within your applications.


File: manual.info,  Node: connector-mxj-usagenotes-packaging,  Next: connector-mxj-usagenotes-customdb,  Prev: connector-mxj-usagenotes,  Up: connector-mxj-usagenotes

20.4.6.1 Creating your own Connector/MXJ Package
................................................

To create a custom Connector/MXJ package that includes a specific
`mysqld' version or platform, extract and rebuild the
`mysql-connector-mxj.jar' (Connector/MXJ v5.0.3 or earlier) or
`mysql-connector-mxj-gpl-[ver]-db-files.jar' (Connector/MXJ v5.0.4 or
later) file.

First, create a new directory into which you can extract the current
`connector-mxj.jar':

     shell> mkdir custom-mxj
     shell> cd custom-mxj
     shell> jar -xf connector-mxj.jar
     shell> ls
     5-0-22/
     ConnectorMXJObjectTestExample.class
     ConnectorMXJUrlTestExample.class
     META-INF/
     TestDb.class
     com/
     kill.exe

If you are using Connector/MXJ v5.0.4 or later, unpack the
`connector-mxj-db-files.jar':

     shell> mkdir custom-mxj
     shell> cd custom-mxj
     shell> jar -xf connector-mxj-db-files.jar
     shell> ls
     5-0-51a/
     META-INF/
     connector-mxj.properties

The MySQL version directory, `5-0-22' or `5-0-51a' in the preceding
examples, contains all of the files used to create an instance of MySQL
when Connector/MXJ is executed. All of the files in this directory are
required for each version of MySQL to embed. Note as well the format of
the version number, which uses hyphens instead of periods to separate
the version number components.

Within the version specific directory are the platform specific
directories, and archives of the `data' and `share' directory required
by MySQL for the various platforms. For example, here is the listing
for the default Connector/MXJ package:

     shell>> ls
     Linux-i386/
     META-INF/
     Mac_OS_X-ppc/
     SunOS-sparc/
     Win-x86/
     com/
     data_dir.jar
     share_dir.jar
     win_share_dir.jar

Platform specific directories are listed by their OS and platform - for
example the `mysqld' for Mac OS X PowerPC is located within the
`Mac_OS_X-ppc' directory. You can delete directories from this location
that you do not require, and add new directories for additional
platforms that you intend to support.

To add a platform specific `mysqld', create a new directory with the
corresponding name for your operating system/platform. For example, you
could add a directory for Mac OS X/Intel using the directory
`Mac_OS_X-i386'.

On Unix systems, you can determine the platform using `uname':

     shell> uname -p
     i386

In Connector/MXJ v5.0.9 and later, an additional
`platform-map.properties' file is used to associate a specific platform
and operating system combination with the directory in which the
`mysqld' for that combination is located. The determined operating
system and platform are on the left, and the directory name where the
appropriate mysqld is located is on the right. You can see a sample of
the file below:

     Linux-i386=Linux-i386
     Linux-x86=Linux-i386
     Linux-i686=Linux-i386
     Linux-x86_64=Linux-i386
     Linux-ia64=Linux-i386

     #Linux-ppc=Linux-ppc
     #Linux-ppc64=Linux-ppc

     Mac_OS_X-i386=Mac_OS_X-i386
     Mac_OS_X-ppc=Mac_OS_X-ppc
     Rhapsody-PowerPC=Mac_OS_X-ppc
     #Mac_OS-PowerPC=
     #macos-PowerPC=
     #MacOS-PowerPC=

     SunOS-sparc=SunOS-sparc
     Solaris-sparc=SunOS-sparc
     SunOS-x86=SunOS-x86
     Solaris-x86=SunOS-x86

     FreeBSD-x86=FreeBSD-x86

     Windows_Vista-x86=Win-x86
     Windows_2003-x86=Win-x86
     Windows_XP-x86=Win-x86
     Windows_2000-x86=Win-x86
     Windows_NT-x86=Win-x86
     Windows_NT_(unknown)-x86=Win-x86

Now download or compile `mysqld' for the MySQL version and platform you
want to include in your custom `connector-mxj.jar' package into the new
directory.

Create a file called `version.txt' in the OS/platform directory you
have just created that contains the version string/path of the mysqld
binary. For example:

     mysql-5.0.22-osx10.3-i386/bin/mysqld

You can now recreate the `connector-mxj.jar' file with the added
`mysqld':

     shell> cd custom-mxj
     shell> jar -cf ../connector-mxj.jar *

For Connector/MXJ v5.0.4 and later, you should repackage to the
`connector-mxj-db-files.jar':

     shell> cd custom-mxj
     shell> jar -cf ../mysql-connector-mxj-gpl-[ver]-db-files.jar *

You should test this package using the steps outlined in *Note
connector-mxj-install-quickstart::.

*Note*:

Because the `mysql-connector-mxj-gpl-[ver]-db-files.jar' file is
separate from the main Connector/MXJ classes you can distribute
different `mysql-connector-mxj-gpl-[ver]-db-files.jar' files to
different hosts or for different projects without having to create a
completely new main `mysql-connector-mxj-gpl-[ver].jar' file for each
one.


File: manual.info,  Node: connector-mxj-usagenotes-customdb,  Next: connector-mxj-usagenotes-jmx-agent,  Prev: connector-mxj-usagenotes-packaging,  Up: connector-mxj-usagenotes

20.4.6.2 Deploying Connector/MXJ with a pre-configured database
...............................................................

To include a pre-configured/populated database within your
Connector/MXJ JAR file you must create a custom `data_dir.jar' file, as
included within the main `connector-mxj.jar' (Connector/MXJ 5.0.3 or
earlier) or `mysql-connector-mxj-gpl-[ver]-db-files.jar' (Connector/MXJ
5.0.4 or later) file:

  1. First extract the `connector-mxj.jar' or
     `mysql-connector-gpl-[ver]-db-files.jar' file, as outlined in the
     previous section (see *Note connector-mxj-usagenotes-packaging::).

  2. First, create your database and populate the database with the
     information you require in an existing instance of MySQL -
     including Connector/MXJ instances. Data file formats are
     compatible across platforms.

  3. Shutdown the instance of MySQL.

  4. Create a JAR file of the data directory and databases that you
     intend to include your Connector/MXJ package. You should include
     the `mysql' database, which includes user authentication
     information, in addition to the specific databases to include. For
     example, to create a JAR of the `mysql' and `mxjtest' databases:

          shell> jar -cf ../data_dir.jar mysql mxjtest

  5. For Connector/MXJ 5.0.3 or earlier, copy the `data_dir.jar' file
     into the extracted `connector-mxj.jar' directory, and then create
     an archive for `connector-mxj.jar'.

     For Connector/MXJ 5.0.4 or later, copy the `data_dir.jar' file
     into the extracted `mysql-connector-mxj-gpl-[ver]-db-files.jar'
     directory, and then create an archive for
     `mysql-connector-mxj-db-gpl-[ver]--files.jar'.

Note that if you are create databases using the InnoDB engine, you must
include the `ibdata.*' and `ib_logfile*' files within the
`data_dir.jar' archive.


File: manual.info,  Node: connector-mxj-usagenotes-jmx-agent,  Next: connector-mxj-usagenotes-standard-environment,  Prev: connector-mxj-usagenotes-customdb,  Up: connector-mxj-usagenotes

20.4.6.3 Running within a JMX Agent (custom)
............................................

As a JMX MBean, MySQL Connector/MXJ requires a JMX v1.2 compliant MBean
container, such as JBoss version 4. The MBean will uses the standard
JMX management APIs to present (and allow the setting of) parameters
which are appropriate for that platform.

If you are not using the SUN Reference implementation of the JMX
libraries, you should skip this section. Or, if you are deploying to
JBoss, you also may wish to skip to the next section.

We want to see the MysqldDynamicMBean in action inside of a JMX agent.
In the `com.mysql.management.jmx.sunri' package is a custom JMX agent
with two MBeans:

  1. The MysqldDynamicMBean, and

  2. A com.sun.jdmk.comm.HtmlAdaptorServer, which provides a web
     interface for manipulating the beans inside of a JMX agent.

When this very simple agent is started, it will allow a MySQL database
to be started and stopped with a web browser.

  1. Complete the testing of the platform as above.

        * Current JDK, JUnit, Connector/J, MySQL Connector/MXJ

        * This section _requires_ the SUN reference implementation of
          JMX

        * `PATH', `JAVA_HOME', `ANT_HOME', `CLASSPATH'

  2. If not building from source, skip to next step

     Rebuild with the "sunri.present"

          ant -Dsunri.present=true dist
          re-run tests:
          java junit.textui.TestRunner com.mysql.management.AllTestsSuite

  3. Launch the test agent from the command line:

          java com.mysql.management.jmx.sunri.MysqldTestAgentSunHtmlAdaptor &

  4. From a browser:

          http://localhost:9092/

  5. Under MysqldAgent,

          select "name=mysqld"

  6. Observe the MBean View

  7. Scroll to the bottom of the screen press the `startMysqld' button

  8. Click `Back to MBean View'

  9. Scroll to the bottom of the screen press `stopMysqld' button

 10. Kill the java process running the Test Agent (jmx server)


File: manual.info,  Node: connector-mxj-usagenotes-standard-environment,  Prev: connector-mxj-usagenotes-jmx-agent,  Up: connector-mxj-usagenotes

20.4.6.4 Deployment in a standard JMX Agent environment (JBoss)
...............................................................

Once there is confidence that the MBean will function on the platform,
deploying the MBean inside of a standard JMX Agent is the next step.
Included are instructions for deploying to JBoss.

  1. Ensure a current version of java development kit (v1.4.x), see
     above.

        * Ensure `JAVA_HOME' is set (JBoss requires `JAVA_HOME')

        * Ensure `JAVA_HOME/bin' is in the `PATH' (You will NOT need to
          set your CLASSPATH, nor will you need any of the jars used in
          the previous tests).

  2. Ensure a current version of JBoss (v4.0RC1 or better)

          http://www.jboss.org/index.html
          select "Downloads"
          select "jboss-4.0.zip"
          pick a mirror
          unzip ~/dload/jboss-4.0.zip
          create a JBOSS_HOME environment variable set to the unzipped directory
          unix only:
          cd $JBOSS_HOME/bin
          chmod +x *.sh

  3. Deploy (copy) the `connector-mxj.jar' to
     `$JBOSS_HOME/server/default/lib'.

  4. Deploy (copy) `mysql-connector-java-3.1.4-beta-bin.jar' to
     `$JBOSS_HOME/server/default/lib'.

  5. Create a `mxjtest.war' directory in
     `$JBOSS_HOME/server/default/deploy'.

  6. Deploy (copy) `index.jsp' to
     `$JBOSS_HOME/server/default/deploy/mxjtest.war'.

  7. Create a `mysqld-service.xml' file in
     `$JBOSS_HOME/server/default/deploy'.

          <?xml version="1.0" encoding="UTF-8"?>
           <server>
            <mbean code="com.mysql.management.jmx.jboss.JBossMysqldDynamicMBean"
               name="mysql:type=service,name=mysqld">
            <attribute name="datadir">/tmp/xxx_data_xxx</attribute>
            <attribute name="autostart">true</attribute>
            </mbean>
           </server>

  8. Start jboss:

        * On unix: `$JBOSS_HOME/bin/run.sh'

        * On windows: `%JBOSS_HOME%\bin\run.bat'

     Be ready: JBoss sends a lot of output to the screen.

  9. When JBoss seems to have stopped sending output to the screen,
     open a web browser to: `http://localhost:8080/jmx-console'

 10. Scroll down to the bottom of the page in the `mysql' section,
     select the bulleted `mysqld' link.

 11. Observe the JMX MBean View page. MySQL should already be running.

 12. (If "autostart=true" was set, you may skip this step.)  Scroll to
     the bottom of the screen. You may press the `Invoke' button to
     stop (or start) MySQL observe `Operation completed successfully
     without a return value.' Click `Back to MBean View'

 13. To confirm MySQL is running, open a web browser to
     `http://localhost:8080/mxjtest/' and you should see that

          SELECT 1

     returned with a result of

          1

 14. Guided by the
     `$JBOSS_HOME/server/default/deploy/mxjtest.war/index.jsp' you will
     be able to use MySQL in your Web Application. There is a `test'
     database and a `root' user (no password) ready to experiment with.
     Try creating a table, inserting some rows, and doing some selects.

 15. Shut down MySQL. MySQL will be stopped automatically when JBoss is
     stopped, or: from the browser, scroll down to the bottom of the
     MBean View press the stop service `Invoke' button to halt the
     service.  Observe `Operation completed successfully without a
     return value.' Using `ps' or `task manager' see that MySQL is no
     longer running

As of 1.0.6-beta version is the ability to have the MBean start the
MySQL database upon start up. Also, we've taken advantage of the JBoss
life-cycle extension methods so that the database will gracefully shut
down when JBoss is shutdown.


File: manual.info,  Node: connector-mxj-samples,  Next: connector-mxj-support,  Prev: connector-mxj-usagenotes,  Up: connector-mxj

20.4.7 Connector/MXJ Samples
----------------------------

* Menu:

* connector-mxj-samples-jsp::    Using Connector/MXJ with JSP

This section contains some sample applications using Connector/MXJ.


File: manual.info,  Node: connector-mxj-samples-jsp,  Prev: connector-mxj-samples,  Up: connector-mxj-samples

20.4.7.1 Using Connector/MXJ with JSP
.....................................

The following web application was provided by Pavan Venkatesh as an
example of a JSP based application using Connector/MXJ to provide
contact data. The example consists of two components, `insertdata.jsp'
and `response.jsp'. The `insertdata.jsp' provides a form into which you
can enter information to be stored within the MySQL database provided
by Connector/MXJ. The `response.jsp' file is called when you submit the
form and then provides a table of the data.

Because the data is stored through Connector/MXJ the instantiation of
the MySQL database is handled dynamically on the fly, making the script
lightweight and self-contained.

     <%@page contentType="text/html" pageEncoding="UTF-8"%>
     <!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN"
        "http://www.w3.org/TR/html4/loose.dtd">
     <%@ page import="java.sql.*"%>
     <%@ page import="java.io.*"%>
     <%@ page import="java.io.*"%>
     <%@ page import="java.sql.*"%>

     <HTML>
     <HEAD>
     <TITLE>insert data</TITLE>
     <script language="Javascript">

     function validFields(){

     if (document.form2.ID.value == "" || document.form2.ID.value == null){
     alert ( "Please enter ID / Field cannot be left blank" );
     return false;
     }

     if (document.form2.names.value == "" || document.form2.names.value == null){
     alert ( "Please enter Name / Field cannot be left blank" );
     return false;
     }
     if (document.form2.place.value == ""|| document.form2.place.value == null){
     alert ( "Please enter Place / Field cannot be left blank" );
     return false;
     }
     if (document.form2.phone.value == ""|| document.form2.phone.value == null){
     alert ( "Please enter Phone number / Field cannot be left blank" );
     return false;
     }
     return true;
     }
     </script>
     </HEAD>

     <BODY bgcolor="#ffffcc">

     <H1>Welcome to MySQL world</H1>

     <H2>MySQL with MXJ Connection</H2>

     <P>Insert data in existing "contactdetails2009" table under
     "Directory" database</P>

     <FORM action="response.jsp" method="get" name="form2">

     <TABLE style="background-color: #ECE5B6;" WIDTH="30%">

     	<TR>
     		<TH width="50%">
     		<center>ID</center>
     		</TH>
     		<TD width="50%"><INPUT TYPE="text" NAME="ID"></TD>
     	</TR>

     	<TR>
     		<TH width="50%">
     		<center>Name</center>
     		</TH>
     		<TD width="50%"><INPUT TYPE="text" NAME="names"></TD>
     	</TR>

     	<TR>
     		<TH width="50%">
     		<center>City</center>
     		</TH>
     		<TD width="50%"><INPUT TYPE="text" NAME="place"></TD>
     	</TR>

     	<TR>
     		<TH width="50%">
     		<center>Phone</center>
     		</TH>
     		<TD width="50%"><INPUT TYPE="text" NAME="phone"></TD>
     	</TR>

     	<TR>
     		<TH></TH>
     		<TD width="50%"><INPUT TYPE="submit" VALUE="Insert"
     			OnClick="return validFields();"></TD>
     	</TR>

     </TABLE>
     </FORM>

     </BODY>

     <%@ page import="java.sql.*"%>
     <%@ page import="java.sql.*"%>
     <%@ page import="java.io.*"%>
     <%@ page import="java.io.*"%>
     <%@ page import="java.sql.*"%>
     <%@ page import="java.sql.Connection"%>
     <%@ page import="java.sql.DriverManager"%>
     <%@ page language="java"%>
     <%@ page import=" com.mysql.management.util.QueryUtil"%>

     <%@page contentType="text/html" pageEncoding="UTF-8"%>
     <!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN"
        "http://www.w3.org/TR/html4/loose.dtd">

     <HTML>
     <HEAD>
     <META http-equiv="Content-Type" content="text/html; charset=UTF-8">
     <TITLE>JSP Page</TITLE>
     </HEAD>

     <BODY bgcolor="#ffffcc">

     <P><INPUT type=button value="Back" onCLick="history.back()"></P>

     <H1>Welcome to Directory Database</H1>
     <%
             String ID = request.getParameter("ID");
             String name = request.getParameter("names");
             String city = request.getParameter("place");
             String phone = request.getParameter("phone");

             File ourAppDir1 = new File("/tmp/src");
             File databaseDir1 = new File(ourAppDir1,"database");
             int port = 4336;
             String dbName = "Directory";

           try
                     {
             String url = "jdbc:mysql:mxj://localhost:" + port + "/" + dbName //
                     + "?" + "server.basedir=" + databaseDir1 //
                     + "&" + "createDatabaseIfNotExist=true"//
                     + "&" + "server.initialize-user=true" //
                     ;

         Connection connection = null;
         int updateQuery=0;

      Class.forName("com.mysql.jdbc.Driver").newInstance();

            String userName = "alice";
             String password = "q93uti0opwhkd";
                 connection = DriverManager.getConnection(url, userName, password);
                   PreparedStatement pstatement = null;

                  String sql = "SELECT VERSION()";
                 String queryForString = new QueryUtil(connection).queryForString(sql);

                 String command = "INSERT INTO contactdetails2009 (ID, name,city,phone) VALUES (?,?,?,?)";

                  pstatement = connection.prepareStatement(command);
                  pstatement.setString(1, ID);
                  pstatement.setString(2, name);
     			 pstatement.setString(3, city);
     			 pstatement.setString(4, phone);
                             updateQuery =  pstatement.executeUpdate();

                 ResultSet resultset = pstatement.executeQuery("select * from contactdetails2009");

                   if (updateQuery != 0) { %>

     <P>MySQL Version------------&gt; <%         out.println(queryForString);          %>
     </P>

     <TABLE style="background-color: #ECE5B6;" WIDTH="50%">

     	<TR>
     		<TH style="text-align: center;">Data successfully inserted into
     		MySQL database using MXJ connection</TH>
     	</TR>
     	<TR>
     		<th style="text-align: center;">Storage Engine used is MyISAM</th>
     	</TR>
     	<TR>
     		<TD>
     		<H2>ContactDetails2009 Table</H2>
     		<TABLE cellpadding="10" border="1" style="background-color: #ffffcc;">
     			<TR>
     				<TH>ID</TH>
     				<TH>name</TH>
     				<TH>city</TH>
     				<TH>phone</TH>
     			</TR>

     			<%
                 while(resultset.next()){
             %>

     			<TR>
     				<TD><%= resultset.getString(1) %></TD>

     				<TD><%= resultset.getString(2) %></TD>

     				<TD><%= resultset.getString(3) %></TD>

     				<TD><%= resultset.getString(4) %></TD>
     			</TR>

     			<%
                } %>

     			<%

                     resultset.close();
                    pstatement.close();
                    connection.close();
                    }
                 }

            catch (Exception e) {

         %>

     			<TR>
     				<TD>ERROR------------&gt; <%
                     out.println("ID or Row already exist");
                 }
             %>
     				</TD>
     			</TR>
     		</TABLE>
     		</TD>
     	</TR>
     </TABLE>

     </BODY>

     </HTML>


File: manual.info,  Node: connector-mxj-support,  Prev: connector-mxj-samples,  Up: connector-mxj

20.4.8 Connector/MXJ Support
----------------------------

* Menu:

* connector-mxj-support-community::  Connector/MXJ Community Support
* connector-mxj-support-bug-report::  How to Report Connector/MXJ Problems
* connector-mxj-support-changelog::  Connector/MXJ Change History

There are a wide variety of options available for obtaining support for
using Connector/MXJ. You should contact the Connector/MXJ community for
help before reporting a potential bug or problem. See *Note
connector-mxj-support-community::.


File: manual.info,  Node: connector-mxj-support-community,  Next: connector-mxj-support-bug-report,  Prev: connector-mxj-support,  Up: connector-mxj-support

20.4.8.1 Connector/MXJ Community Support
........................................

Oracle provides assistance to the user community by means of a number
of mailing lists and web based forums.

You can find help and support through the MySQL and Java
(http://lists.mysql.com/java) mailing list.

For information about subscribing to MySQL mailing lists or to browse
list archives, visit `http://lists.mysql.com/'. See *Note
mailing-lists::.

Community support from experienced users is also available through the
JDBC and Java (http://forums.mysql.com/list.php?39) forum. You may also
find help from other users in the other MySQL Forums, located at
`http://forums.mysql.com'. See *Note forums::.


File: manual.info,  Node: connector-mxj-support-bug-report,  Next: connector-mxj-support-changelog,  Prev: connector-mxj-support-community,  Up: connector-mxj-support

20.4.8.2 How to Report Connector/MXJ Problems
.............................................

If you encounter difficulties or problems with Connector/MXJ, contact
the Connector/MXJ community *Note connector-mxj-support-community::.

If reporting a problem, you should ideally include the following
information with the email:

   * Operating system and version

   * Connector/MXJ version

   * MySQL server version

   * Copies of error messages or other unexpected output

   * Simple reproducible sample

Remember that the more information you can supply to us, the more
likely it is that we can fix the problem.

If you believe the problem to be a bug, then you must report the bug
through `http://bugs.mysql.com/'.


File: manual.info,  Node: connector-mxj-support-changelog,  Prev: connector-mxj-support-bug-report,  Up: connector-mxj-support

20.4.8.3 Connector/MXJ Change History
.....................................

The Connector/MXJ Change History (Changelog) is located with the main
Changelog for MySQL. See *Note news-connector-mxj::.


File: manual.info,  Node: connector-c,  Next: connector-ooo,  Prev: connector-mxj,  Up: connectors-apis

20.5 MySQL Connector/C
======================

* Menu:

* connector-c-building::         Building MySQL Connector/C from the Source Code
* connector-c-testing::          Testing MySQL Connector/C
* connector-c-faq::              MySQL Connector/C FAQ

*What is MySQL Connector/C?*

MySQL Connector/C is a C client library for client/server
communication. It is a standalone replacement for the MySQL Client
Library shipped with the MySQL Server.

*Why have a replacement for MySQL Client Library?*

There is no need to compile or install the MySQL Server package if you
only need the client library.

MySQL Connector/C does not rely on the MySQL Server release cycle, so
bug fixes and new features are released more often.

MySQL Connector/C API documentation is available here *Note
c-api-functions::.

Supported platforms include:

   * Windows

   * Windows x64

   * Linux

   * Solaris

   * FreeBSD

   * Mac OS X

   * HP-UX

   * IBM AIX

   * IBM i5/OS


File: manual.info,  Node: connector-c-building,  Next: connector-c-testing,  Prev: connector-c,  Up: connector-c

20.5.1 Building MySQL Connector/C from the Source Code
------------------------------------------------------

*Obtaining the Source Code*

A TAR file containing the source code can be downloaded
(http://dev.mysql.com/downloads/connector/c/#downloads) from the MySQL
Developers site. Select the source code package from the drop down list.

The source code for development releases of the connector can be found
at Launchpad. The project home page can be found here
(http://launchpad.net/libmysql).

The source code for the 1.0 branch can be found here
(https://code.launchpad.net/~libmysql-team/libmysql/1.0).

To obtain the code, you must have Bazaar installed. Use the command
`bzr branch lp:libmysql'.

   * *Building on Unix*

     Examples of supported Unix or Unix-like operating systems include:

        * Solaris

        * Linux

        * HP-UX

        * AIX

        * OS X

     *Compiler Tools*

     Ideally, the native compiler tool set for the target platform is
     used for compilation. This would be SunStudio for Solaris and aCC
     for HP-UX for example. However, the GNU tool-chain can be used
     across all platforms.

     You also need `CMake' 2.6 or newer, which is available online
     (http://www.cmake.org).

     *To Build*

     If using GNU AutoTools change to the MySQL Connector/C source
     directory and follow the procedure below.

       1. To generate the makefile enter:

               shell> cmake -G "Unix Makefiles"

          or for a Debug build enter:

               shell> cmake -G "Unix Makefiles" -DCMAKE_BUILD_TYPE=Debug

       2. Then build the project using:

               shell> make

     *To Install*

     By default make install will install the MySQL Connector/C files
     in the `/usr/local' directory. You can change this behavior by
     specifying another directory when generating the `makefile':

          shell> cmake -G "Unix Makefiles" -DCMAKE_INSTALL_PREFIX=/mypath

     Now, in the root shell, enter the following to install the MySQL
     Connector/C libraries and tools:

          root-shell> make install

     At this point all of the MySQL Connector/C files will be in place.

   * *Building on Microsoft Windows*

     Older versions of Microsoft Windows are not supported.  Supported
     versions are Windows 2000, Windows XP, Windows Vista, Windows
     Server 2003, or Windows Server 2008.

     *Compiler Tools*

     Microsoft Visual Studio 8 and 9 are recommended. The Express
     Edition of Visual Studio and other compilers may work, but are
     untested.

     You also need `CMake' 2.6 or newer, available at
     http://www.cmake.org

     *To Build*

     Set the environment variables for the Visual Studio toolchain.
     Visual Studio includes a batch file to set these for you, and
     installs a shortcut into the `Start' menu to open a command prompt
     with these variables set.

     Build MySQL Connector/C using the `CMake' command-line tool by
     entering the following from the source root directory in a command
     prompt window:

          shell> cmake -G "Visual Studio 9 2008"

     This produces a project file that you can open with Visual Studio
     or build from the command line with either of:

          shell> devenv.com libmysql.sln /build Release

          shell> devenv.com libmysql.sln /build RelWithDebInfo

     For other versions of Visual Studio or `nmake' based build, run
     the following command:

          shell> cmake --help

     to check the supported generators.

     To compile the Debug build, you must run set the `CMake' build
     type so the correct version of external libraries are used:

          shell> cmake -G "Visual Studio 8 2005" -DCMAKE_BUILD_TYPE=Debug

     Followed by:

          shell> devenv.com libmysql.sln /build Debug

     *To Install*

     To create a install package you can choose between two variants:

       1. Creating a Zip package

       2. Creating an MSI install package

        * *Zip package*

          To create a Zip package, run the `cpack' command from the
          root of your MySQL Connector/C source directory.

        * *MSI Install package*

          The required tools include Windows XML Installer toolset
          (WIX), which is available online
          (http://sourceforge.net/projects/wix/).

          To create the MSI install package change to the subdirectory
          `win' and generate the `makefile':

               shell> cmake -G "NMake Makefiles"

          Create the MSI install package by calling `nmake':

               shell> nmake

*Build Options*

The following options can be used when building the MySQL Connector/C
source code:

Build Option           Description
-DWITH_OPENSSL=1       Enables dynamic linking to the
                       system OpenSSL library.
-DWITH_EXTERNAL_ZLIB=1 Enables dynamic linking to the
                       system Zlib library.


File: manual.info,  Node: connector-c-testing,  Next: connector-c-faq,  Prev: connector-c-building,  Up: connector-c

20.5.2 Testing MySQL Connector/C
--------------------------------

For testing MySQL Connector/C, you need a running MySQL server
instance. Before you run the test suite, specify the following
environment variables:

   * `MYSQL_TEST_HOST' (default localhost)

   * `MYSQL_TEST_USER'

   * `MYSQL_TEST_PASSWD'

   * `MYSQL_TEST_PORT'

   * `MYSQL_TEST_SOCKET'

   * `MYSQL_TEST_DB' (default test)

To run the test suite, execute `ctest' from the command line:

     shell> ctest


File: manual.info,  Node: connector-c-faq,  Prev: connector-c-testing,  Up: connector-c

20.5.3 MySQL Connector/C FAQ
----------------------------

*Questions*
   * 20.5.3.1: What is the `MySQL Native C API'? What are its typical
     benefits and use cases?

   * 20.5.3.2: What is `libmysql'?

   * 20.5.3.3: What is `libmysqld'?

   * 20.5.3.4: What is `MySQL Connector/C'?

   * 20.5.3.5: What is the difference between `Native C API',
     `libmysql', `libmysqld' and `MySQL Connector/C'?

   * 20.5.3.6: Does MySQL Connector/C replace any of `Native C API',
     `libmysql' and `libmysqld'?

*Questions and Answers* *20.5.3.1: ** What is the `MySQL Native C API'?
What are its typical benefits and use cases?  *

MySQL Connector/C, also known as `libmysql', or MySQL Native C API, is
a standalone, C-based API and library that you can use in C
applications to connect with the MySQL Server. It implements the same
MySQL client API that has been in use for a decade.

It is also used as the foundation for drivers for standard database
APIs such as ODBC, Perl's DBI, and Python's DB API.

*20.5.3.2: ** What is `libmysql'?  *

`libmysql' is the name of the library that MySQL Connector/C provides.

*20.5.3.3: ** What is `libmysqld'?  *

`libmysqld' is an embedded database server with the same API as MySQL
Connector/C. It is included with the MySQL Server distribution.

*20.5.3.4: ** What is `MySQL Connector/C'?  *

MySQL Connector/C is a standalone distribution of the `libmysql'
library, which was previously only available as part of the MySQL
Server distribution. The version of `libmysql' included with MySQL
Connector/C and the version bundled with the server are functionally
equivalent, but the cross-platform build system for MySQL Connector/C
uses `CMake'.

*20.5.3.5: ** What is the difference between `Native C API',
`libmysql', `libmysqld' and `MySQL Connector/C'?  *

MySQL Connector/C and `libmysql' are the `native C API for MySQL', and
all three terms can be used interchangeably. `libmysqld' is the embedded
version of the MySQL Server, and is included in the server distribution.

*20.5.3.6: ** Does MySQL Connector/C replace any of `Native C API',
`libmysql' and `libmysqld'?  *

MySQL Connector/C contains `libmysql', and implements a native C API.
It does not include `libmysqld', which can be found with the MySQL
server distribution.


File: manual.info,  Node: connector-ooo,  Next: libmysqld,  Prev: connector-c,  Up: connectors-apis

20.6 MySQL Connector/OpenOffice.org
===================================

* Menu:

* connector-ooo-installation::   Installation
* connector-ooo-getting-started::  Getting Started: Connecting to MySQL
* connector-ooo-getting-started-examples::  Getting Started: Usage Examples
* connector-ooo-references::     References
* connector-ooo-bugs::           Known Bugs
* connector-ooo-contact::        Contact

MySQL Connector/OpenOffice.org is a native MySQL database connector for
OpenOffice.org. Currently, it is in preview status and supports
OpenOffice.org 3.1 and above. It can be used to connect OpenOffice.org
applications to a MySQL server.

Before MySQL Connector/OpenOffice.org became available you would have
to use MySQL Connector/J (JDBC) or MySQL Connector/ODBC to connect to a
MySQL server.

Connector/OpenOffice.org is a community project. The source code for
Connector/OpenOffice.org is available under GPL with the FLOSS License
Exception.

*Advantages*

Using MySQL Connector/OpenOffice.org has the following advantages:

   * Easy installation through the OpenOffice.org Extension Manager.

   * Seamless integration into OpenOffice.org.

   * No need to go through an additional Connector installation routine
     (ODBC/JDBC)

   * No need to configure or register an additional Connector (ODBC)

   * No need to install or configure a driver manager (ODBC)

*Status*

MySQL Connector/OpenOffice.org is currently at version 1.0 GA.

If you have any queries please contact us through our mailing list at
<users@dba.openoffice.org>


File: manual.info,  Node: connector-ooo-installation,  Next: connector-ooo-getting-started,  Prev: connector-ooo,  Up: connector-ooo

20.6.1 Installation
-------------------

  1. Install or upgrade to OpenOffice.org 3.1.

  2. Download MySQL Connector/OpenOffice.org from The OpenOffice.org
     extension download site
     (http://extensions.services.openoffice.org/project/mysql_connector).
     Save the file corresponding to your platform. Currently supported
     platforms are Windows, Linux, Linux x86-64, Mac OS X, Solaris x86
     and Solaris SPARC.

  3. Add the `.oxt' extension through the Extension Manager of
     OpenOffice.org. In OpenOffice.org, select `Tools', `Extension
     Manager...' and specify the `.oxt' file as a new extension. When
     done, MySQL Connector/OpenOffice.org will show up as a new
     extension in the Extension Manager.

     FIGURE GOES HERE: Adding an Extension

  4. Restart OpenOffice.org.


File: manual.info,  Node: connector-ooo-getting-started,  Next: connector-ooo-getting-started-examples,  Prev: connector-ooo-installation,  Up: connector-ooo

20.6.2 Getting Started: Connecting to MySQL
-------------------------------------------

MySQL Connector/OpenOffice.org enables you to access the MySQL Server
and its schemata from the OpenOffice.org suite.

The following example demonstrates the creation of a new OpenOffice.org
Base database which uses a local MySQL Server for storage and the new
connector for connecting.

  1. * Select the database*

     Create a new database by selecting `File', `New', `Database'. This
     starts a wizard that enables you to create a new database, open an
     existing database, or connect to an existing database.  Select the
     `Connect to existing database' radio button. From the listbox
     select MySQL. Click `Next >>'.

     FIGURE GOES HERE: Selecting the Database

  2. You will be asked how you would like to connect to the database.
     Select the `Connect native' radio button.

     FIGURE GOES HERE: Selecting the connection type

     Click `Next >>'.

  3. * Fill in the connection settings*

     Enter the name of the database, server URL, and optionally the
     socket to connect on (if not using the default).

     Note that if you do not specify a database all databases will be
     available for selection.

     FIGURE GOES HERE: Entering Connection Settings

     Click `Next >>'.

  4. * Set up user authentication*

     If you are using MySQL server's anonymous account without a
     password, you do not have to fill in anything in this step.
     Otherwise, fill in your MySQL user name and check the password
     check box. Note, for security reasons, you should not normally use
     the anonymous account without a password.

     FIGURE GOES HERE: Setting Up User Authentication

     You can now test your connection to the MySQL database server by
     clicking the `Test Connection' button.  Check the check box if you
     do not want OpenOffice.org to ask you for your password again in
     the current session. Testing the connection is optional, although
     recommended.

     Click `Next >>'.

  5. * Decide how to proceed after connecting to the database *

     FIGURE GOES HERE: After Connecting to the Database

     Keep the default settings.

     Click `Finish'.

  6. You will then be prompted to save you database as a database file.
     Enter the name of the database and the location in which to save
     the file.

     FIGURE GOES HERE: Entering the Database File Name

     Click `Save'.

You will be located in the Base application with your database tables
displayed.


File: manual.info,  Node: connector-ooo-getting-started-examples,  Next: connector-ooo-references,  Prev: connector-ooo-getting-started,  Up: connector-ooo

20.6.3 Getting Started: Usage Examples
--------------------------------------

*Listing Tables*

In the `Database' area of the `Base' main window, select `Tables'. If
this is the first time you are accessing the database you will be
prompted for your credentials (user name and password); you can store
these settings for your current Base session.

FIGURE GOES HERE: Listing Tables

Depending on your connection settings you will now see all databases
with all their tables, or just the database you have specified in the
connection settings.


File: manual.info,  Node: connector-ooo-references,  Next: connector-ooo-bugs,  Prev: connector-ooo-getting-started-examples,  Up: connector-ooo

20.6.4 References
-----------------

See the OpenOffice.org Web site (http://www.openoffice.org/) for
documentation of the office suite and its Extension Manager.


File: manual.info,  Node: connector-ooo-bugs,  Next: connector-ooo-contact,  Prev: connector-ooo-references,  Up: connector-ooo

20.6.5 Known Bugs
-----------------

If you discover a bug in Connector/OpenOffice.org please add it to this
list
(http://wiki.services.openoffice.org/wiki/Database/Drivers/MySQL_Native#Known_issues)
and send an email to <users@dba.openoffice.org>. You need to be logged
in with an OpenOffice.org account for both; see the project mailing
list (http://dba.openoffice.org/servlets/ProjectMailingListList) for
details.


File: manual.info,  Node: connector-ooo-contact,  Prev: connector-ooo-bugs,  Up: connector-ooo

20.6.6 Contact
--------------

To discuss the new MySQL Connector/OpenOffice.org, please subscribe to
the mailing list <users@dba.openoffice.org>. It is a low-volume list
with less than 10 mails per day.


File: manual.info,  Node: libmysqld,  Next: c,  Prev: connector-ooo,  Up: connectors-apis

20.7 libmysqld, the Embedded MySQL Server Library
=================================================

* The embedded MySQL server library is NOT part of MySQL 5.0. It is
part of previous editions and will be included in future versions,
starting with MySQL 5.1. You can find appropriate documentation in the
corresponding manuals for these versions. In this manual, only an
overview of the embedded library is provided. *

The embedded MySQL server library makes it possible to run a
full-featured MySQL server inside a client application. The main
benefits are increased speed and more simple management for embedded
applications.

The embedded server library is based on the client/server version of
MySQL, which is written in C/C++. Consequently, the embedded server
also is written in C/C++. There is no embedded server available in
other languages.

The API is identical for the embedded MySQL version and the
client/server version. To change an old threaded application to use the
embedded library, you normally only have to add calls to the following
functions.

Function           When to Call
*Note              Should be called before any other MySQL function
`mysql_library_init()':is called, preferably early in the `main()'
mysql-library-init.function.
*Note              Should be called before your program exits.
`mysql_library_end()':
mysql-library-end. 
*Note              Should be called in each thread you create that
`mysql_thread_init()':accesses MySQL.
mysql-thread-init. 
*Note              Should be called before calling `pthread_exit()'
`mysql_thread_end()':
mysql-thread-end.  

Then you must link your code with `libmysqld.a' instead of
`libmysqlclient.a'. To ensure binary compatibility between your
application and the server library, be sure to compile your application
against headers for the same series of MySQL that was used to compile
the server library. For example, if `libmysqld' was compiled against
MySQL 4.1 headers, do not compile your application against MySQL 5.1
headers, or vice versa.

The `mysql_library_XXX()' functions are also included in
`libmysqlclient.a' to enable you to change between the embedded and the
client/server version by just linking your application with the right
library. See *Note mysql-library-init::.

One difference between the embedded server and the standalone server is
that for the embedded server, authentication for connections is
disabled by default. To use authentication for the embedded server,
specify the `--with-embedded-privilege-control' option when you invoke
`configure' to configure your MySQL distribution.


File: manual.info,  Node: c,  Next: apis-php,  Prev: libmysqld,  Up: connectors-apis

20.8 MySQL C API
================

* Menu:

* c-api-data-structures::        C API Data Structures
* c-api-function-overview::      C API Function Overview
* c-api-functions::              C API Function Descriptions
* c-api-prepared-statements::    C API Prepared Statements
* c-api-prepared-statement-data-structures::  C API Prepared Statement Data Structures
* c-api-prepared-statement-function-overview::  C API Prepared Statement Function Overview
* c-api-prepared-statement-functions::  C API Prepared Statement Function Descriptions
* c-api-thread-functions::       C API Threaded Function Descriptions
* c-api-embedded-server-functions::  C API Embedded Server Function Descriptions
* c-api-problems::               Common Questions and Problems When Using the C API
* auto-reconnect::               Controlling Automatic Reconnection Behavior
* c-api-multiple-queries::       C API Support for Multiple Statement Execution
* c-api-prepared-statement-problems::  C API Prepared Statement Problems
* c-api-prepared-statement-date-handling::  C API Prepared Statement Handling of Date and Time Values
* c-api-prepared-call-statements::  C API Support for Prepared `CALL' Statements
* building-clients::             Building Client Programs

The C API code is distributed with MySQL. It is included in the
`mysqlclient' library and enables C programs to access a database.

Many of the clients in the MySQL source distribution are written in C.
If you are looking for examples that demonstrate how to use the C API,
take a look at these clients. You can find these in the `client'
directory in the MySQL source distribution.

Most of the other client APIs (all except Connector/J and
Connector/Net) use the `mysqlclient' library to communicate with the
MySQL server. This means that, for example, you can take advantage of
many of the same environment variables that are used by other client
programs, because they are referenced from the library. See *Note
programs::, for a list of these variables.

The client has a maximum communication buffer size. The size of the
buffer that is allocated initially (16KB) is automatically increased up
to the maximum size (the maximum is 16MB). Because buffer sizes are
increased only as demand warrants, simply increasing the default
maximum limit does not in itself cause more resources to be used.  This
size check is mostly a check for erroneous statements and communication
packets.

The communication buffer must be large enough to contain a single SQL
statement (for client-to-server traffic) and one row of returned data
(for server-to-client traffic). Each thread's communication buffer is
dynamically enlarged to handle any query or row up to the maximum
limit. For example, if you have *Note `BLOB': blob. values that contain
up to 16MB of data, you must have a communication buffer limit of at
least 16MB (in both server and client). The client's default maximum is
16MB, but the default maximum in the server is 1MB. You can increase
this by changing the value of the `max_allowed_packet' parameter when
the server is started. See *Note server-parameters::.

The MySQL server shrinks each communication buffer to
`net_buffer_length' bytes after each query. For clients, the size of
the buffer associated with a connection is not decreased until the
connection is closed, at which time client memory is reclaimed.

For programming with threads, see *Note threaded-clients::. For
creating a standalone application which includes the "server" and
"client" in the same program (and does not communicate with an external
MySQL server), see *Note libmysqld::.

*Note*:

If, after an upgrade, you experience problems with compiled client
programs, such as `Commands out of sync' or unexpected core dumps, you
probably have used old header or library files when compiling your
programs. In this case, you should check the date for your `mysql.h'
file and `libmysqlclient.a' library to verify that they are from the
new MySQL distribution. If not, recompile your programs with the new
headers and libraries. Recompilation might also be necessary for
programs compiled against the shared client library if the library
major version number has changed (for example from
`libmysqlclient.so.15' to `libmysqlclient.so.16'.


File: manual.info,  Node: c-api-data-structures,  Next: c-api-function-overview,  Prev: c,  Up: c

20.8.1 C API Data Structures
----------------------------

This section describes C API data structures other than those used for
prepared statements. For information about the latter, see *Note
c-api-prepared-statement-data-structures::.

   * `MYSQL'

     This structure represents a handle to one database connection.  It
     is used for almost all MySQL functions. You should not try to make
     a copy of a `MYSQL' structure. There is no guarantee that such a
     copy will be usable.

   * `MYSQL_RES'

     This structure represents the result of a query that returns rows
     (*Note `SELECT': select, *Note `SHOW': show, *Note `DESCRIBE':
     describe, *Note `EXPLAIN': explain.). The information returned
     from a query is called the _result set_ in the remainder of this
     section.

   * `MYSQL_ROW'

     This is a type-safe representation of one row of data. It is
     currently implemented as an array of counted byte strings.  (You
     cannot treat these as null-terminated strings if field values may
     contain binary data, because such values may contain null bytes
     internally.) Rows are obtained by calling *Note
     `mysql_fetch_row()': mysql-fetch-row.

   * `MYSQL_FIELD'

     This structure contains metadata: information about a field, such
     as the field's name, type, and size. Its members are described in
     more detail later in this section. You may obtain the
     `MYSQL_FIELD' structures for each field by calling *Note
     `mysql_fetch_field()': mysql-fetch-field.  repeatedly. Field
     values are not part of this structure; they are contained in a
     `MYSQL_ROW' structure.

   * `MYSQL_FIELD_OFFSET'

     This is a type-safe representation of an offset into a MySQL field
     list. (Used by *Note `mysql_field_seek()': mysql-field-seek.)
     Offsets are field numbers within a row, beginning at zero.

   * `my_ulonglong'

     The type used for the number of rows and for *Note
     `mysql_affected_rows()': mysql-affected-rows, *Note
     `mysql_num_rows()': mysql-num-rows, and *Note `mysql_insert_id()':
     mysql-insert-id. This type provides a range of `0' to `1.84e19'.

     On some systems, attempting to print a value of type
     `my_ulonglong' does not work. To print such a value, convert it to
     `unsigned long' and use a `%lu' print format. Example:

          printf ("Number of rows: %lu\n",
                  (unsigned long) mysql_num_rows(result));

   * `my_bool'

     A boolean type, for values that are true (nonzero) or false (zero).

The `MYSQL_FIELD' structure contains the members described in the
following list:

   * `char * name'

     The name of the field, as a null-terminated string. If the field
     was given an alias with an `AS' clause, the value of `name' is the
     alias.

   * `char * org_name'

     The name of the field, as a null-terminated string. Aliases are
     ignored.

   * `char * table'

     The name of the table containing this field, if it isn't a
     calculated field. For calculated fields, the `table' value is an
     empty string. If the column is selected from a view, `table' names
     the view. If the table or view was given an alias with an `AS'
     clause, the value of `table' is the alias. For a *Note `UNION':
     union, the value is the empty string.

   * `char * org_table'

     The name of the table, as a null-terminated string. Aliases are
     ignored. If the column is selected from a view, `org_table' names
     the underlying table. For a *Note `UNION': union, the value is the
     empty string.

   * `char * db'

     The name of the database that the field comes from, as a
     null-terminated string. If the field is a calculated field, `db'
     is an empty string. For a *Note `UNION': union, the value is the
     empty string.

   * `char * catalog'

     The catalog name. This value is always `"def"'.

   * `char * def'

     The default value of this field, as a null-terminated string.
     This is set only if you use *Note `mysql_list_fields()':
     mysql-list-fields.

   * `unsigned long length'

     The width of the field. This corresponds to the display length, in
     bytes.

     The server determines the `length' value before it generates the
     result set, so this is the minimum length required for a data type
     capable of holding the largest possible value from the result
     column, without knowing in advance the actual values that will be
     produced by the query for the result set.

   * `unsigned long max_length'

     The maximum width of the field for the result set (the length in
     bytes of the longest field value for the rows actually in the
     result set). If you use *Note `mysql_store_result()':
     mysql-store-result. or *Note `mysql_list_fields()':
     mysql-list-fields, this contains the maximum length for the field.
     If you use *Note `mysql_use_result()': mysql-use-result, the value
     of this variable is zero.

     The value of `max_length' is the length of the string
     representation of the values in the result set. For example, if
     you retrieve a *Note `FLOAT': numeric-types. column and the
     `widest' value is `-12.345', `max_length' is 7 (the length of
     `'-12.345'').

     If you are using prepared statements, `max_length' is not set by
     default because for the binary protocol the lengths of the values
     depend on the types of the values in the result set. (See *Note
     c-api-prepared-statement-data-structures::.)  If you want the
     `max_length' values anyway, enable the
     `STMT_ATTR_UPDATE_MAX_LENGTH' option with *Note
     `mysql_stmt_attr_set()': mysql-stmt-attr-set. and the lengths will
     be set when you call *Note `mysql_stmt_store_result()':
     mysql-stmt-store-result.  (See *Note mysql-stmt-attr-set::, and
     *Note mysql-stmt-store-result::.)

   * `unsigned int name_length'

     The length of `name'.

   * `unsigned int org_name_length'

     The length of `org_name'.

   * `unsigned int table_length'

     The length of `table'.

   * `unsigned int org_table_length'

     The length of `org_table'.

   * `unsigned int db_length'

     The length of `db'.

   * `unsigned int catalog_length'

     The length of `catalog'.

   * `unsigned int def_length'

     The length of `def'.

   * `unsigned int flags'

     Bit-flags that describe the field. The `flags' value may have zero
     or more of the bits set that are shown in the following table.

     Flag Value                  Flag Description
     `NOT_NULL_FLAG'             Field can't be `NULL'
     `PRI_KEY_FLAG'              Field is part of a primary key
     `UNIQUE_KEY_FLAG'           Field is part of a unique key
     `MULTIPLE_KEY_FLAG'         Field is part of a nonunique key
     `UNSIGNED_FLAG'             Field has the `UNSIGNED' attribute
     `ZEROFILL_FLAG'             Field has the `ZEROFILL' attribute
     `BINARY_FLAG'               Field has the `BINARY' attribute
     `AUTO_INCREMENT_FLAG'       Field has the `AUTO_INCREMENT' attribute
     `NUM_FLAG'                  Field is numeric
     `ENUM_FLAG'                 Field is an *Note `ENUM': enum.
                                 (deprecated)
     `SET_FLAG'                  Field is a *Note `SET': set.
                                 (deprecated)
     `BLOB_FLAG'                 Field is a *Note `BLOB': blob. or *Note
                                 `TEXT': blob. (deprecated)
     `TIMESTAMP_FLAG'            Field is a *Note `TIMESTAMP': datetime.
                                 (deprecated)
     `NUM_FLAG'                  Field is numeric; see additional notes
                                 following table
     `NO_DEFAULT_VALUE_FLAG'     Field has no default value; see
                                 additional notes following table

     Some of these flags indicate data type information and are
     superseded by or used in conjunction with the `MYSQL_TYPE_XXX'
     value in the `field->type' member described later:

        * To check for *Note `BLOB': blob. or *Note `TIMESTAMP':
          datetime. values, check whether `type' is `MYSQL_TYPE_BLOB' or
          `MYSQL_TYPE_TIMESTAMP'. (The `BLOB_FLAG' and `TIMESTAMP_FLAG'
          flags are unneeded.)

        * *Note `ENUM': enum. and *Note `SET': set. values are returned
          as strings. For these, check that the `type' value is
          `MYSQL_TYPE_STRING' and that the `ENUM_FLAG' or `SET_FLAG'
          flag is set in the `flags' value.

     `NUM_FLAG' indicates that a column is numeric. This includes
     columns with a type of `MYSQL_TYPE_DECIMAL', `MYSQL_TYPE_TINY',
     `MYSQL_TYPE_SHORT', `MYSQL_TYPE_LONG', `MYSQL_TYPE_FLOAT',
     `MYSQL_TYPE_DOUBLE', `MYSQL_TYPE_NULL', `MYSQL_TYPE_LONGLONG',
     `MYSQL_TYPE_INT24', and `MYSQL_TYPE_YEAR'.

     `NO_DEFAULT_VALUE_FLAG' indicates that a column has no `DEFAULT'
     clause in its definition. This does not apply to `NULL' columns
     (because such columns have a default of `NULL'), or to
     `AUTO_INCREMENT' columns (which have an implied default value).
     `NO_DEFAULT_VALUE_FLAG' was added in MySQL 5.0.2.

     The following example illustrates a typical use of the `flags'
     value:

          if (field->flags & NOT_NULL_FLAG)
              printf("Field can't be null\n");

     You may use the convenience macros shown in the following table to
     determine the boolean status of the `flags' value.

     Flag Status                 Description
     `IS_NOT_NULL(flags)'        True if this field is defined as `NOT
                                 NULL'
     `IS_PRI_KEY(flags)'         True if this field is a primary key
     `IS_BLOB(flags)'            True if this field is a *Note `BLOB':
                                 blob. or *Note `TEXT': blob.
                                 (deprecated; test `field->type' instead)

   * `unsigned int decimals'

     The number of decimals for numeric fields.

   * `unsigned int charsetnr'

     An ID number that indicates the character set/collation pair for
     the field.

     To distinguish between binary and nonbinary data for string data
     types, check whether the `charsetnr' value is 63. If so, the
     character set is `binary', which indicates binary rather than
     nonbinary data. This enables you to distinguish *Note `BINARY':
     binary-varbinary. from *Note `CHAR': char, *Note `VARBINARY':
     binary-varbinary. from *Note `VARCHAR': char, and the *Note
     `BLOB': blob. types from the *Note `TEXT': blob. types.

     `charsetnr' values are the same as those displayed in the `Id'
     column of the *Note `SHOW COLLATION': show-collation. statement or
     the `ID' column of the `INFORMATION_SCHEMA' *Note `COLLATIONS':
     collations-table. table. You can use those information sources to
     see which character set and collation specific `charsetnr' values
     indicate:

          mysql> SHOW COLLATION WHERE Id = 63;
          +-----------+---------+----+---------+----------+---------+
          | Collation | Charset | Id | Default | Compiled | Sortlen |
          +-----------+---------+----+---------+----------+---------+
          | binary    | binary  | 63 | Yes     | Yes      |       1 |
          +-----------+---------+----+---------+----------+---------+

          mysql> SELECT COLLATION_NAME, CHARACTER_SET_NAME
              -> FROM INFORMATION_SCHEMA.COLLATIONS WHERE ID = 33;
          +-----------------+--------------------+
          | COLLATION_NAME  | CHARACTER_SET_NAME |
          +-----------------+--------------------+
          | utf8_general_ci | utf8               |
          +-----------------+--------------------+

   * `enum enum_field_types type'

     The type of the field. The `type' value may be one of the
     `MYSQL_TYPE_' symbols shown in the following table.

     Type Value              Type Description
     `MYSQL_TYPE_TINY'       *Note `TINYINT': numeric-types. field
     `MYSQL_TYPE_SHORT'      *Note `SMALLINT': numeric-types. field
     `MYSQL_TYPE_LONG'       *Note `INTEGER': numeric-types. field
     `MYSQL_TYPE_INT24'      *Note `MEDIUMINT': numeric-types. field
     `MYSQL_TYPE_LONGLONG'   *Note `BIGINT': numeric-types. field
     `MYSQL_TYPE_DECIMAL'    *Note `DECIMAL': numeric-types. or *Note
                             `NUMERIC': numeric-types. field
     `MYSQL_TYPE_NEWDECIMAL' Precision math *Note `DECIMAL':
                             numeric-types. or *Note `NUMERIC':
                             numeric-types. field (MySQL 5.0.3 and up)
     `MYSQL_TYPE_FLOAT'      *Note `FLOAT': numeric-types. field
     `MYSQL_TYPE_DOUBLE'     *Note `DOUBLE': numeric-types. or *Note
                             `REAL': numeric-types. field
     `MYSQL_TYPE_BIT'        *Note `BIT': numeric-types. field (MySQL
                             5.0.3 and up)
     `MYSQL_TYPE_TIMESTAMP'  *Note `TIMESTAMP': datetime. field
     `MYSQL_TYPE_DATE'       *Note `DATE': datetime. field
     `MYSQL_TYPE_TIME'       *Note `TIME': time. field
     `MYSQL_TYPE_DATETIME'   *Note `DATETIME': datetime. field
     `MYSQL_TYPE_YEAR'       *Note `YEAR': year. field
     `MYSQL_TYPE_STRING'     *Note `CHAR': char. or *Note `BINARY':
                             binary-varbinary. field
     `MYSQL_TYPE_VAR_STRING' *Note `VARCHAR': char. or *Note
                             `VARBINARY': binary-varbinary. field
     `MYSQL_TYPE_BLOB'       *Note `BLOB': blob. or *Note `TEXT': blob.
                             field (use `max_length' to determine the
                             maximum length)
     `MYSQL_TYPE_SET'        *Note `SET': set. field
     `MYSQL_TYPE_ENUM'       *Note `ENUM': enum. field
     `MYSQL_TYPE_GEOMETRY'   Spatial field
     `MYSQL_TYPE_NULL'       `NULL'-type field

     You can use the `IS_NUM()' macro to test whether a field has a
     numeric type. Pass the `type' value to `IS_NUM()' and it evaluates
     to TRUE if the field is numeric:

          if (IS_NUM(field->type))
              printf("Field is numeric\n");

     *Note `ENUM': enum. and *Note `SET': set. values are returned as
     strings. For these, check that the `type' value is
     `MYSQL_TYPE_STRING' and that the `ENUM_FLAG' or `SET_FLAG' flag is
     set in the `flags' value.


File: manual.info,  Node: c-api-function-overview,  Next: c-api-functions,  Prev: c-api-data-structures,  Up: c

20.8.2 C API Function Overview
------------------------------

The functions available in the C API are summarized here and described
in greater detail in a later section. See *Note c-api-functions::.

*C API Function Names and Descriptions*

Function                Description
*Note `my_init()':      Initialize global variables, and thread handler
my-init.                in thread-safe programs
*Note                   Returns the number of rows
`mysql_affected_rows()':changed/deleted/inserted by the last *Note
mysql-affected-rows.    `UPDATE': update, *Note `DELETE': delete, or
                        *Note `INSERT': insert. query
*Note                   Toggles autocommit mode on/off
`mysql_autocommit()':   
mysql-autocommit.       
*Note                   Changes user and database on an open connection
`mysql_change_user()':  
mysql-change-user.      
*Note                   Return default character set name for current
`mysql_character_set_name()':connection
mysql-character-set-name.
*Note `mysql_close()':  Closes a server connection
mysql-close.            
*Note                   Commits the transaction
`mysql_commit()':       
mysql-commit.           
*Note                   Connects to a MySQL server (this function is
`mysql_connect()':      deprecated; use *Note `mysql_real_connect()':
mysql-connect.          mysql-real-connect.  instead)
*Note                   Creates a database (this function is deprecated;
`mysql_create_db()':    use the SQL statement *Note `CREATE DATABASE':
mysql-create-db.        create-database. instead)
*Note                   Seeks to an arbitrary row number in a query
`mysql_data_seek()':    result set
mysql-data-seek.        
*Note `mysql_debug()':  Does a `DBUG_PUSH' with the given string
mysql-debug.            
*Note                   Drops a database (this function is deprecated;
`mysql_drop_db()':      use the SQL statement *Note `DROP DATABASE':
mysql-drop-db.          drop-database. instead)
*Note                   Makes the server write debug information to the
`mysql_dump_debug_info()':log
mysql-dump-debug-info.  
*Note `mysql_eof()':    Determines whether the last row of a result set
mysql-eof.              has been read (this function is deprecated;
                        *Note `mysql_errno()': mysql-errno. or *Note
                        `mysql_error()': mysql-error. may be used
                        instead)
*Note `mysql_errno()':  Returns the error number for the most recently
mysql-errno.            invoked MySQL function
*Note `mysql_error()':  Returns the error message for the most recently
mysql-error.            invoked MySQL function
*Note                   Escapes special characters in a string for use
`mysql_escape_string()':in an SQL statement
mysql-escape-string.    
*Note                   Returns the type of the next table field
`mysql_fetch_field()':  
mysql-fetch-field.      
*Note                   Returns the type of a table field, given a field
`mysql_fetch_field_direct()':number
mysql-fetch-field-direct.
*Note                   Returns an array of all field structures
`mysql_fetch_fields()': 
mysql-fetch-fields.     
*Note                   Returns the lengths of all columns in the
`mysql_fetch_lengths()':current row
mysql-fetch-lengths.    
*Note                   Fetches the next row from the result set
`mysql_fetch_row()':    
mysql-fetch-row.        
*Note                   Returns the number of result columns for the
`mysql_field_count()':  most recent statement
mysql-field-count.      
*Note                   Puts the column cursor on a specified column
`mysql_field_seek()':   
mysql-field-seek.       
*Note                   Returns the position of the field cursor used
`mysql_field_tell()':   for the last *Note `mysql_fetch_field()':
mysql-field-tell.       mysql-fetch-field.
*Note                   Frees memory used by a result set
`mysql_free_result()':  
mysql-free-result.      
*Note                   Return information about default character set
`mysql_get_character_set_info()':
mysql-get-character-set-info.
*Note                   Returns client version information as a string
`mysql_get_client_info()':
mysql-get-client-info.  
*Note                   Returns client version information as an integer
`mysql_get_client_version()':
mysql-get-client-version.
*Note                   Returns a string describing the connection
`mysql_get_host_info()':
mysql-get-host-info.    
*Note                   Returns the protocol version used by the
`mysql_get_proto_info()':connection
mysql-get-proto-info.   
*Note                   Returns the server version number
`mysql_get_server_info()':
mysql-get-server-info.  
*Note                   Returns version number of server as an integer
`mysql_get_server_version()':
mysql-get-server-version.
*Note                   Return current SSL cipher
`mysql_get_ssl_cipher()':
mysql-get-ssl-cipher.   
*Note                   Encode string in hexadecimal format
`mysql_hex_string()':   
mysql-hex-string.       
*Note `mysql_info()':   Returns information about the most recently
mysql-info.             executed query
*Note `mysql_init()':   Gets or initializes a `MYSQL' structure
mysql-init.             
*Note                   Returns the ID generated for an `AUTO_INCREMENT'
`mysql_insert_id()':    column by the previous query
mysql-insert-id.        
*Note `mysql_kill()':   Kills a given thread
mysql-kill.             
*Note                   Finalize the MySQL C API library
`mysql_library_end()':  
mysql-library-end.      
*Note                   Initialize the MySQL C API library
`mysql_library_init()': 
mysql-library-init.     
*Note                   Returns database names matching a simple regular
`mysql_list_dbs()':     expression
mysql-list-dbs.         
*Note                   Returns field names matching a simple regular
`mysql_list_fields()':  expression
mysql-list-fields.      
*Note                   Returns a list of the current server threads
`mysql_list_processes()':
mysql-list-processes.   
*Note                   Returns table names matching a simple regular
`mysql_list_tables()':  expression
mysql-list-tables.      
*Note                   Checks whether any more results exist
`mysql_more_results()': 
mysql-more-results.     
*Note                   Returns/initiates the next result in
`mysql_next_result()':  multiple-result executions
mysql-next-result.      
*Note                   Returns the number of columns in a result set
`mysql_num_fields()':   
mysql-num-fields.       
*Note                   Returns the number of rows in a result set
`mysql_num_rows()':     
mysql-num-rows.         
*Note                   Sets connect options for *Note
`mysql_options()':      `mysql_real_connect()': mysql-real-connect.
mysql-options.          
*Note `mysql_ping()':   Checks whether the connection to the server is
mysql-ping.             working, reconnecting as necessary
*Note `mysql_query()':  Executes an SQL query specified as a
mysql-query.            null-terminated string
*Note                   Connects to a MySQL server
`mysql_real_connect()': 
mysql-real-connect.     
*Note                   Escapes special characters in a string for use
`mysql_real_escape_string()':in an SQL statement, taking into account the
mysql-real-escape-string.current character set of the connection
*Note                   Executes an SQL query specified as a counted
`mysql_real_query()':   string
mysql-real-query.       
*Note                   Flush or reset tables and caches
`mysql_refresh()':      
mysql-refresh.          
*Note                   Tells the server to reload the grant tables
`mysql_reload()':       
mysql-reload.           
*Note                   Rolls back the transaction
`mysql_rollback()':     
mysql-rollback.         
*Note                   Seeks to a row offset in a result set, using
`mysql_row_seek()':     value returned from *Note `mysql_row_tell()':
mysql-row-seek.         mysql-row-tell.
*Note                   Returns the row cursor position
`mysql_row_tell()':     
mysql-row-tell.         
*Note                   Selects a database
`mysql_select_db()':    
mysql-select-db.        
*Note                   Finalize the MySQL C API library
`mysql_server_end()':   
mysql-server-end.       
*Note                   Initialize the MySQL C API library
`mysql_server_init()':  
mysql-server-init.      
*Note                   Set default character set for current connection
`mysql_set_character_set()':
mysql-set-character-set.
*Note                   Set the *Note `LOAD DATA LOCAL INFILE':
`mysql_set_local_infile_default()':load-data. handler callbacks to their default
mysql-set-local-infile-default.values
*Note                   Install application-specific *Note `LOAD DATA
`mysql_set_local_infile_handler()':LOCAL INFILE': load-data. handler callbacks
mysql-set-local-infile-handler.
*Note                   Sets an option for the connection (like
`mysql_set_server_option()':`multi-statements')
mysql-set-server-option.
*Note                   Returns the SQLSTATE error code for the last
`mysql_sqlstate()':     error
mysql-sqlstate.         
*Note                   Shuts down the database server
`mysql_shutdown()':     
mysql-shutdown.         
*Note                   Prepare to establish SSL connection to server
`mysql_ssl_set()':      
mysql-ssl-set.          
*Note `mysql_stat()':   Returns the server status as a string
mysql-stat.             
*Note                   Retrieves a complete result set to the client
`mysql_store_result()': 
mysql-store-result.     
*Note                   Finalize thread handler
`mysql_thread_end()':   
mysql-thread-end.       
*Note                   Returns the current thread ID
`mysql_thread_id()':    
mysql-thread-id.        
*Note                   Initialize thread handler
`mysql_thread_init()':  
mysql-thread-init.      
*Note                   Returns 1 if the clients are compiled as
`mysql_thread_safe()':  thread-safe
mysql-thread-safe.      
*Note                   Initiates a row-by-row result set retrieval
`mysql_use_result()':   
mysql-use-result.       
*Note                   Returns the warning count for the previous SQL
`mysql_warning_count()':statement
mysql-warning-count.    

Application programs should use this general outline for interacting
with MySQL:

  1. Initialize the MySQL library by calling *Note
     `mysql_library_init()': mysql-library-init. This function exists
     in both the `mysqlclient' C client library and the `mysqld'
     embedded server library, so it is used whether you build a regular
     client program by linking with the `-libmysqlclient' flag, or an
     embedded server application by linking with the `-libmysqld' flag.

  2. Initialize a connection handler by calling *Note `mysql_init()':
     mysql-init. and connect to the server by calling *Note
     `mysql_real_connect()': mysql-real-connect.

  3. Issue SQL statements and process their results. (The following
     discussion provides more information about how to do this.)

  4. Close the connection to the MySQL server by calling *Note
     `mysql_close()': mysql-close.

  5. End use of the MySQL library by calling *Note
     `mysql_library_end()': mysql-library-end.

The purpose of calling *Note `mysql_library_init()':
mysql-library-init. and *Note `mysql_library_end()': mysql-library-end.
is to provide proper initialization and finalization of the MySQL
library. For applications that are linked with the client library, they
provide improved memory management. If you don't call *Note
`mysql_library_end()': mysql-library-end, a block of memory remains
allocated. (This does not increase the amount of memory used by the
application, but some memory leak detectors will complain about it.)
For applications that are linked with the embedded server, these calls
start and stop the server.

*Note `mysql_library_init()': mysql-library-init. and *Note
`mysql_library_end()': mysql-library-end. are available as of MySQL
5.0.3. For older versions of MySQL, you can call *Note
`mysql_server_init()': mysql-server-init. and *Note
`mysql_server_end()': mysql-server-end. instead.

In a nonmulti-threaded environment, the call to *Note
`mysql_library_init()': mysql-library-init. may be omitted, because
*Note `mysql_init()': mysql-init. will invoke it automatically as
necessary. However, *Note `mysql_library_init()': mysql-library-init.
is not thread-safe in a multi-threaded environment, and thus neither is
*Note `mysql_init()': mysql-init, which calls *Note
`mysql_library_init()': mysql-library-init. You must either call *Note
`mysql_library_init()': mysql-library-init.  prior to spawning any
threads, or else use a mutex to protect the call, whether you invoke
*Note `mysql_library_init()': mysql-library-init. or indirectly through
*Note `mysql_init()': mysql-init. This should be done prior to any
other client library call.

To connect to the server, call *Note `mysql_init()': mysql-init. to
initialize a connection handler, then call *Note
`mysql_real_connect()': mysql-real-connect. with that handler (along
with other information such as the host name, user name, and password).
Upon connection, *Note `mysql_real_connect()': mysql-real-connect. sets
the `reconnect' flag (part of the `MYSQL' structure) to a value of `1'
in versions of the API older than 5.0.3, or `0' in newer versions. A
value of `1' for this flag indicates that if a statement cannot be
performed because of a lost connection, to try reconnecting to the
server before giving up. As of MySQL 5.0.13, you can use the
`MYSQL_OPT_RECONNECT' option to *Note `mysql_options()': mysql-options.
to control reconnection behavior. When you are done with the
connection, call *Note `mysql_close()': mysql-close. to terminate it.

While a connection is active, the client may send SQL statements to the
server using *Note `mysql_query()': mysql-query.  or *Note
`mysql_real_query()': mysql-real-query. The difference between the two
is that *Note `mysql_query()': mysql-query. expects the query to be
specified as a null-terminated string whereas *Note
`mysql_real_query()': mysql-real-query. expects a counted string. If
the string contains binary data (which may include null bytes), you
must use *Note `mysql_real_query()': mysql-real-query.

For each non-*Note `SELECT': select. query (for example, *Note
`INSERT': insert, *Note `UPDATE': update, *Note `DELETE': delete.), you
can find out how many rows were changed (affected) by calling *Note
`mysql_affected_rows()': mysql-affected-rows.

For *Note `SELECT': select. queries, you retrieve the selected rows as
a result set. (Note that some statements are *Note `SELECT':
select.-like in that they return rows. These include *Note `SHOW': show,
*Note `DESCRIBE': describe, and *Note `EXPLAIN': explain. They should
be treated the same way as *Note `SELECT': select. statements.)

There are two ways for a client to process result sets. One way is to
retrieve the entire result set all at once by calling *Note
`mysql_store_result()': mysql-store-result. This function acquires from
the server all the rows returned by the query and stores them in the
client. The second way is for the client to initiate a row-by-row
result set retrieval by calling *Note `mysql_use_result()':
mysql-use-result. This function initializes the retrieval, but does not
actually get any rows from the server.

In both cases, you access rows by calling *Note `mysql_fetch_row()':
mysql-fetch-row. With *Note `mysql_store_result()': mysql-store-result,
*Note `mysql_fetch_row()': mysql-fetch-row. accesses rows that have
previously been fetched from the server. With *Note
`mysql_use_result()': mysql-use-result, *Note `mysql_fetch_row()':
mysql-fetch-row. actually retrieves the row from the server.
Information about the size of the data in each row is available by
calling *Note `mysql_fetch_lengths()': mysql-fetch-lengths.

After you are done with a result set, call *Note `mysql_free_result()':
mysql-free-result. to free the memory used for it.

The two retrieval mechanisms are complementary. Client programs should
choose the approach that is most appropriate for their requirements. In
practice, clients tend to use *Note `mysql_store_result()':
mysql-store-result. more commonly.

An advantage of *Note `mysql_store_result()': mysql-store-result. is
that because the rows have all been fetched to the client, you not only
can access rows sequentially, you can move back and forth in the result
set using *Note `mysql_data_seek()': mysql-data-seek.  or *Note
`mysql_row_seek()': mysql-row-seek. to change the current row position
within the result set. You can also find out how many rows there are by
calling *Note `mysql_num_rows()': mysql-num-rows. On the other hand,
the memory requirements for *Note `mysql_store_result()':
mysql-store-result. may be very high for large result sets and you are
more likely to encounter out-of-memory conditions.

An advantage of *Note `mysql_use_result()': mysql-use-result.  is that
the client requires less memory for the result set because it maintains
only one row at a time (and because there is less allocation overhead,
*Note `mysql_use_result()': mysql-use-result. can be faster).
Disadvantages are that you must process each row quickly to avoid tying
up the server, you don't have random access to rows within the result
set (you can only access rows sequentially), and you don't know how
many rows are in the result set until you have retrieved them all.
Furthermore, you _must_ retrieve all the rows even if you determine in
mid-retrieval that you've found the information you were looking for.

The API makes it possible for clients to respond appropriately to
statements (retrieving rows only as necessary) without knowing whether
the statement is a *Note `SELECT': select.  You can do this by calling
*Note `mysql_store_result()': mysql-store-result. after each *Note
`mysql_query()': mysql-query. (or *Note `mysql_real_query()':
mysql-real-query.). If the result set call succeeds, the statement was a
*Note `SELECT': select. and you can read the rows.  If the result set
call fails, call *Note `mysql_field_count()': mysql-field-count. to
determine whether a result was actually to be expected. If *Note
`mysql_field_count()': mysql-field-count. returns zero, the statement
returned no data (indicating that it was an *Note `INSERT': insert,
*Note `UPDATE': update, *Note `DELETE': delete, and so forth), and was
not expected to return rows. If *Note `mysql_field_count()':
mysql-field-count. is nonzero, the statement should have returned rows,
but didn't. This indicates that the statement was a *Note `SELECT':
select. that failed. See the description for *Note
`mysql_field_count()': mysql-field-count. for an example of how this
can be done.

Both *Note `mysql_store_result()': mysql-store-result. and *Note
`mysql_use_result()': mysql-use-result. enable you to obtain
information about the fields that make up the result set (the number of
fields, their names and types, and so forth). You can access field
information sequentially within the row by calling *Note
`mysql_fetch_field()': mysql-fetch-field.  repeatedly, or by field
number within the row by calling *Note `mysql_fetch_field_direct()':
mysql-fetch-field-direct. The current field cursor position may be
changed by calling *Note `mysql_field_seek()': mysql-field-seek.
Setting the field cursor affects subsequent calls to *Note
`mysql_fetch_field()': mysql-fetch-field. You can also get information
for fields all at once by calling *Note `mysql_fetch_fields()':
mysql-fetch-fields.

For detecting and reporting errors, MySQL provides access to error
information by means of the *Note `mysql_errno()': mysql-errno. and
*Note `mysql_error()': mysql-error. functions. These return the error
code or error message for the most recently invoked function that can
succeed or fail, enabling you to determine when an error occurred and
what it was.


File: manual.info,  Node: c-api-functions,  Next: c-api-prepared-statements,  Prev: c-api-function-overview,  Up: c

20.8.3 C API Function Descriptions
----------------------------------

* Menu:

* mysql-affected-rows::          `mysql_affected_rows()'
* mysql-autocommit::             `mysql_autocommit()'
* mysql-change-user::            `mysql_change_user()'
* mysql-character-set-name::     `mysql_character_set_name()'
* mysql-close::                  `mysql_close()'
* mysql-commit::                 `mysql_commit()'
* mysql-connect::                `mysql_connect()'
* mysql-create-db::              `mysql_create_db()'
* mysql-data-seek::              `mysql_data_seek()'
* mysql-debug::                  `mysql_debug()'
* mysql-drop-db::                `mysql_drop_db()'
* mysql-dump-debug-info::        `mysql_dump_debug_info()'
* mysql-eof::                    `mysql_eof()'
* mysql-errno::                  `mysql_errno()'
* mysql-error::                  `mysql_error()'
* mysql-escape-string::          `mysql_escape_string()'
* mysql-fetch-field::            `mysql_fetch_field()'
* mysql-fetch-field-direct::     `mysql_fetch_field_direct()'
* mysql-fetch-fields::           `mysql_fetch_fields()'
* mysql-fetch-lengths::          `mysql_fetch_lengths()'
* mysql-fetch-row::              `mysql_fetch_row()'
* mysql-field-count::            `mysql_field_count()'
* mysql-field-seek::             `mysql_field_seek()'
* mysql-field-tell::             `mysql_field_tell()'
* mysql-free-result::            `mysql_free_result()'
* mysql-get-character-set-info::  `mysql_get_character_set_info()'
* mysql-get-client-info::        `mysql_get_client_info()'
* mysql-get-client-version::     `mysql_get_client_version()'
* mysql-get-host-info::          `mysql_get_host_info()'
* mysql-get-proto-info::         `mysql_get_proto_info()'
* mysql-get-server-info::        `mysql_get_server_info()'
* mysql-get-server-version::     `mysql_get_server_version()'
* mysql-get-ssl-cipher::         `mysql_get_ssl_cipher()'
* mysql-hex-string::             `mysql_hex_string()'
* mysql-info::                   `mysql_info()'
* mysql-init::                   `mysql_init()'
* mysql-insert-id::              `mysql_insert_id()'
* mysql-kill::                   `mysql_kill()'
* mysql-library-end::            `mysql_library_end()'
* mysql-library-init::           `mysql_library_init()'
* mysql-list-dbs::               `mysql_list_dbs()'
* mysql-list-fields::            `mysql_list_fields()'
* mysql-list-processes::         `mysql_list_processes()'
* mysql-list-tables::            `mysql_list_tables()'
* mysql-more-results::           `mysql_more_results()'
* mysql-next-result::            `mysql_next_result()'
* mysql-num-fields::             `mysql_num_fields()'
* mysql-num-rows::               `mysql_num_rows()'
* mysql-options::                `mysql_options()'
* mysql-ping::                   `mysql_ping()'
* mysql-query::                  `mysql_query()'
* mysql-real-connect::           `mysql_real_connect()'
* mysql-real-escape-string::     `mysql_real_escape_string()'
* mysql-real-query::             `mysql_real_query()'
* mysql-refresh::                `mysql_refresh()'
* mysql-reload::                 `mysql_reload()'
* mysql-rollback::               `mysql_rollback()'
* mysql-row-seek::               `mysql_row_seek()'
* mysql-row-tell::               `mysql_row_tell()'
* mysql-select-db::              `mysql_select_db()'
* mysql-set-character-set::      `mysql_set_character_set()'
* mysql-set-local-infile-default::  `mysql_set_local_infile_default()'
* mysql-set-local-infile-handler::  `mysql_set_local_infile_handler()'
* mysql-set-server-option::      `mysql_set_server_option()'
* mysql-shutdown::               `mysql_shutdown()'
* mysql-sqlstate::               `mysql_sqlstate()'
* mysql-ssl-set::                `mysql_ssl_set()'
* mysql-stat::                   `mysql_stat()'
* mysql-store-result::           `mysql_store_result()'
* mysql-thread-id::              `mysql_thread_id()'
* mysql-use-result::             `mysql_use_result()'
* mysql-warning-count::          `mysql_warning_count()'

In the descriptions here, a parameter or return value of `NULL' means
`NULL' in the sense of the C programming language, not a MySQL `NULL'
value.

Functions that return a value generally return a pointer or an integer.
Unless specified otherwise, functions returning a pointer return a
non-`NULL' value to indicate success or a `NULL' value to indicate an
error, and functions returning an integer return zero to indicate
success or nonzero to indicate an error. Note that `nonzero' means just
that. Unless the function description says otherwise, do not test
against a value other than zero:

     if (result)                   /* correct */
         ... error ...

     if (result < 0)               /* incorrect */
         ... error ...

     if (result == -1)             /* incorrect */
         ... error ...

When a function returns an error, the *Errors* subsection of the
function description lists the possible types of errors. You can find
out which of these occurred by calling *Note `mysql_errno()':
mysql-errno. A string representation of the error may be obtained by
calling *Note `mysql_error()': mysql-error.


File: manual.info,  Node: mysql-affected-rows,  Next: mysql-autocommit,  Prev: c-api-functions,  Up: c-api-functions

20.8.3.1 `mysql_affected_rows()'
................................

`my_ulonglong mysql_affected_rows(MYSQL *mysql)'

* Description *

*Note `mysql_affected_rows()': mysql-affected-rows. may be called
immediately after executing a statement with *Note `mysql_query()':
mysql-query. or *Note `mysql_real_query()': mysql-real-query. It returns
the number of rows changed, deleted, or inserted by the last statement
if it was an *Note `UPDATE': update, *Note `DELETE': delete, or *Note
`INSERT': insert. For *Note `SELECT': select. statements, *Note
`mysql_affected_rows()': mysql-affected-rows. works like *Note
`mysql_num_rows()': mysql-num-rows.

For *Note `UPDATE': update. statements, the affected-rows value by
default is the number of rows actually changed. If you specify the
`CLIENT_FOUND_ROWS' flag to *Note `mysql_real_connect()':
mysql-real-connect.  when connecting to *Note `mysqld': mysqld, the
affected-rows value is the number of rows `found'; that is, matched by
the `WHERE' clause.

For *Note `REPLACE': replace. statements, the affected-rows value is 2
if the new row replaced an old row, because in this case, one row was
inserted after the duplicate was deleted.

For *Note `INSERT ... ON DUPLICATE KEY UPDATE': insert-on-duplicate.
statements, the affected-rows value is 1 if the row is inserted as a
new row and 2 if an existing row is updated.

Following a *Note `CALL': call. statement for a stored procedure, *Note
`mysql_affected_rows()': mysql-affected-rows. returns the value that it
would return for the last statement executed within the procedure, or
`0' if that statement would return `-1'. Within the procedure, you can
use `ROW_COUNT()' at the SQL level to obtain the affected-rows value
for individual statements.

* Return Values *

An integer greater than zero indicates the number of rows affected or
retrieved. Zero indicates that no records were updated for an *Note
`UPDATE': update. statement, no rows matched the `WHERE' clause in the
query or that no query has yet been executed. -1 indicates that the
query returned an error or that, for a *Note `SELECT': select. query,
*Note `mysql_affected_rows()': mysql-affected-rows. was called prior to
calling *Note `mysql_store_result()': mysql-store-result.

Because *Note `mysql_affected_rows()': mysql-affected-rows.  returns an
unsigned value, you can check for -1 by comparing the return value to
`(my_ulonglong)-1' (or to `(my_ulonglong)~0', which is equivalent).

* Errors *

None.

* Example *

     char *stmt = "UPDATE products SET cost=cost*1.25
                   WHERE group=10";
     mysql_query(&mysql,stmt);
     printf("%ld products updated",
            (long) mysql_affected_rows(&mysql));


File: manual.info,  Node: mysql-autocommit,  Next: mysql-change-user,  Prev: mysql-affected-rows,  Up: c-api-functions

20.8.3.2 `mysql_autocommit()'
.............................

`my_bool mysql_autocommit(MYSQL *mysql, my_bool mode)'

* Description *

Sets autocommit mode on if `mode' is 1, off if `mode' is 0.

* Return Values *

Zero if successful. Nonzero if an error occurred.

* Errors *

None.


File: manual.info,  Node: mysql-change-user,  Next: mysql-character-set-name,  Prev: mysql-autocommit,  Up: c-api-functions

20.8.3.3 `mysql_change_user()'
..............................

`my_bool mysql_change_user(MYSQL *mysql, const char *user, const char
*password, const char *db)'

* Description *

Changes the user and causes the database specified by `db' to become
the default (current) database on the connection specified by `mysql'.
In subsequent queries, this database is the default for table
references that do not include an explicit database specifier.

*Note `mysql_change_user()': mysql-change-user. fails if the connected
user cannot be authenticated or doesn't have permission to use the
database. In this case, the user and database are not changed

The `db' parameter may be set to `NULL' if you don't want to have a
default database.

This command resets the state as if one had done a new connect.  (See
*Note auto-reconnect::.) It always performs a *Note `ROLLBACK': commit.
of any active transactions, closes and drops all temporary tables, and
unlocks all locked tables. Session system variables are reset to the
values of the corresponding global system variables. Prepared
statements are released and *Note `HANDLER': handler. variables are
closed.  Locks acquired with `GET_LOCK()' are released. These effects
occur even if the user didn't change.

* Return Values *

Zero for success. Nonzero if an error occurred.

* Errors *

The same that you can get from *Note `mysql_real_connect()':
mysql-real-connect.

   * `CR_COMMANDS_OUT_OF_SYNC'

     Commands were executed in an improper order.

   * `CR_SERVER_GONE_ERROR'

     The MySQL server has gone away.

   * `CR_SERVER_LOST'

     The connection to the server was lost during the query.

   * `CR_UNKNOWN_ERROR'

     An unknown error occurred.

   * `ER_UNKNOWN_COM_ERROR'

     The MySQL server doesn't implement this command (probably an old
     server).

   * `ER_ACCESS_DENIED_ERROR'

     The user or password was wrong.

   * `ER_BAD_DB_ERROR'

     The database didn't exist.

   * `ER_DBACCESS_DENIED_ERROR'

     The user did not have access rights to the database.

   * `ER_WRONG_DB_NAME'

     The database name was too long.

* Example *

     if (mysql_change_user(&mysql, "user", "password", "new_database"))
     {
        fprintf(stderr, "Failed to change user.  Error: %s\n",
                mysql_error(&mysql));
     }


File: manual.info,  Node: mysql-character-set-name,  Next: mysql-close,  Prev: mysql-change-user,  Up: c-api-functions

20.8.3.4 `mysql_character_set_name()'
.....................................

`const char *mysql_character_set_name(MYSQL *mysql)'

* Description *

Returns the default character set name for the current connection.

* Return Values *

The default character set name

* Errors *

None.


File: manual.info,  Node: mysql-close,  Next: mysql-commit,  Prev: mysql-character-set-name,  Up: c-api-functions

20.8.3.5 `mysql_close()'
........................

`void mysql_close(MYSQL *mysql)'

* Description *

Closes a previously opened connection.  *Note `mysql_close()':
mysql-close. also deallocates the connection handle pointed to by
`mysql' if the handle was allocated automatically by *Note
`mysql_init()': mysql-init. or *Note `mysql_connect()': mysql-connect.

* Return Values *

None.

* Errors *

None.


File: manual.info,  Node: mysql-commit,  Next: mysql-connect,  Prev: mysql-close,  Up: c-api-functions

20.8.3.6 `mysql_commit()'
.........................

`my_bool mysql_commit(MYSQL *mysql)'

* Description *

Commits the current transaction.

As of MySQL 5.0.3, the action of this function is subject to the value
of the `completion_type' system variable. In particular, if the value of
`completion_type' is 2, the server performs a release after terminating
a transaction and closes the client connection. The client program
should call *Note `mysql_close()': mysql-close. to close the connection
from the client side.

* Return Values *

Zero if successful. Nonzero if an error occurred.

* Errors *

None.


File: manual.info,  Node: mysql-connect,  Next: mysql-create-db,  Prev: mysql-commit,  Up: c-api-functions

20.8.3.7 `mysql_connect()'
..........................

`MYSQL *mysql_connect(MYSQL *mysql, const char *host, const char *user,
const char *passwd)'

* Description *

This function is deprecated. Use *Note `mysql_real_connect()':
mysql-real-connect. instead.

*Note `mysql_connect()': mysql-connect. attempts to establish a
connection to a MySQL database engine running on `host'.  *Note
`mysql_connect()': mysql-connect. must complete successfully before you
can execute any of the other API functions, with the exception of *Note
`mysql_get_client_info()': mysql-get-client-info.

The meanings of the parameters are the same as for the corresponding
parameters for *Note `mysql_real_connect()': mysql-real-connect. with
the difference that the connection parameter may be `NULL'. In this
case, the C API allocates memory for the connection structure
automatically and frees it when you call *Note `mysql_close()':
mysql-close. The disadvantage of this approach is that you can't
retrieve an error message if the connection fails. (To get error
information from *Note `mysql_errno()': mysql-errno. or *Note
`mysql_error()': mysql-error, you must provide a valid `MYSQL' pointer.)

* Return Values *

Same as for *Note `mysql_real_connect()': mysql-real-connect.

* Errors *

Same as for *Note `mysql_real_connect()': mysql-real-connect.


File: manual.info,  Node: mysql-create-db,  Next: mysql-data-seek,  Prev: mysql-connect,  Up: c-api-functions

20.8.3.8 `mysql_create_db()'
............................

`int mysql_create_db(MYSQL *mysql, const char *db)'

* Description *

Creates the database named by the `db' parameter.

This function is deprecated. It is preferable to use *Note
`mysql_query()': mysql-query. to issue an SQL *Note `CREATE DATABASE':
create-database. statement instead.

* Return Values *

Zero if the database was created successfully. Nonzero if an error
occurred.

* Errors *

   * `CR_COMMANDS_OUT_OF_SYNC'

     Commands were executed in an improper order.

   * `CR_SERVER_GONE_ERROR'

     The MySQL server has gone away.

   * `CR_SERVER_LOST'

     The connection to the server was lost during the query.

   * `CR_UNKNOWN_ERROR'

     An unknown error occurred.

* Example *

     if(mysql_create_db(&mysql, "my_database"))
     {
        fprintf(stderr, "Failed to create new database.  Error: %s\n",
                mysql_error(&mysql));
     }


File: manual.info,  Node: mysql-data-seek,  Next: mysql-debug,  Prev: mysql-create-db,  Up: c-api-functions

20.8.3.9 `mysql_data_seek()'
............................

`void mysql_data_seek(MYSQL_RES *result, my_ulonglong offset)'

* Description *

Seeks to an arbitrary row in a query result set. The `offset' value is
a row number and should be in the range from `0' to *Note
`mysql_num_rows(result)-1': mysql-num-rows.

This function requires that the result set structure contains the
entire result of the query, so *Note `mysql_data_seek()':
mysql-data-seek. may be used only in conjunction with *Note
`mysql_store_result()': mysql-store-result, not with *Note
`mysql_use_result()': mysql-use-result.

* Return Values *

None.

* Errors *

None.


File: manual.info,  Node: mysql-debug,  Next: mysql-drop-db,  Prev: mysql-data-seek,  Up: c-api-functions

20.8.3.10 `mysql_debug()'
.........................

`void mysql_debug(const char *debug)'

* Description *

Does a `DBUG_PUSH' with the given string.  *Note `mysql_debug()':
mysql-debug. uses the Fred Fish debug library. To use this function,
you must compile the client library to support debugging. See MySQL
Internals: Porting
(http://forge.mysql.com/wiki/MySQL_Internals_Porting).

* Return Values *

None.

* Errors *

None.

* Example *

The call shown here causes the client library to generate a trace file
in `/tmp/client.trace' on the client machine:

     mysql_debug("d:t:O,/tmp/client.trace");


File: manual.info,  Node: mysql-drop-db,  Next: mysql-dump-debug-info,  Prev: mysql-debug,  Up: c-api-functions

20.8.3.11 `mysql_drop_db()'
...........................

`int mysql_drop_db(MYSQL *mysql, const char *db)'

* Description *

Drops the database named by the `db' parameter.

This function is deprecated. It is preferable to use *Note
`mysql_query()': mysql-query. to issue an SQL *Note `DROP DATABASE':
drop-database. statement instead.

* Return Values *

Zero if the database was dropped successfully. Nonzero if an error
occurred.

* Errors *

   * `CR_COMMANDS_OUT_OF_SYNC'

     Commands were executed in an improper order.

   * `CR_SERVER_GONE_ERROR'

     The MySQL server has gone away.

   * `CR_SERVER_LOST'

     The connection to the server was lost during the query.

   * `CR_UNKNOWN_ERROR'

     An unknown error occurred.

* Example *

     if(mysql_drop_db(&mysql, "my_database"))
       fprintf(stderr, "Failed to drop the database: Error: %s\n",
               mysql_error(&mysql));


File: manual.info,  Node: mysql-dump-debug-info,  Next: mysql-eof,  Prev: mysql-drop-db,  Up: c-api-functions

20.8.3.12 `mysql_dump_debug_info()'
...................................

`int mysql_dump_debug_info(MYSQL *mysql)'

* Description *

Instructs the server to write some debug information to the log.  For
this to work, the connected user must have the `SUPER' privilege.

* Return Values *

Zero if the command was successful. Nonzero if an error occurred.

* Errors *

   * `CR_COMMANDS_OUT_OF_SYNC'

     Commands were executed in an improper order.

   * `CR_SERVER_GONE_ERROR'

     The MySQL server has gone away.

   * `CR_SERVER_LOST'

     The connection to the server was lost during the query.

   * `CR_UNKNOWN_ERROR'

     An unknown error occurred.


File: manual.info,  Node: mysql-eof,  Next: mysql-errno,  Prev: mysql-dump-debug-info,  Up: c-api-functions

20.8.3.13 `mysql_eof()'
.......................

`my_bool mysql_eof(MYSQL_RES *result)'

* Description *

This function is deprecated.  *Note `mysql_errno()': mysql-errno. or
*Note `mysql_error()': mysql-error. may be used instead.

*Note `mysql_eof()': mysql-eof. determines whether the last row of a
result set has been read.

If you acquire a result set from a successful call to *Note
`mysql_store_result()': mysql-store-result, the client receives the
entire set in one operation. In this case, a `NULL' return from *Note
`mysql_fetch_row()': mysql-fetch-row. always means the end of the
result set has been reached and it is unnecessary to call *Note
`mysql_eof()': mysql-eof. When used with *Note `mysql_store_result()':
mysql-store-result, *Note `mysql_eof()': mysql-eof. always returns true.

On the other hand, if you use *Note `mysql_use_result()':
mysql-use-result. to initiate a result set retrieval, the rows of the
set are obtained from the server one by one as you call *Note
`mysql_fetch_row()': mysql-fetch-row. repeatedly.  Because an error may
occur on the connection during this process, a `NULL' return value from
*Note `mysql_fetch_row()': mysql-fetch-row. does not necessarily mean
the end of the result set was reached normally.  In this case, you can
use *Note `mysql_eof()': mysql-eof. to determine what happened. *Note
`mysql_eof()': mysql-eof. returns a nonzero value if the end of the
result set was reached and zero if an error occurred.

Historically, *Note `mysql_eof()': mysql-eof.  predates the standard
MySQL error functions *Note `mysql_errno()': mysql-errno. and *Note
`mysql_error()': mysql-error. Because those error functions provide the
same information, their use is preferred over *Note `mysql_eof()':
mysql-eof, which is deprecated. (In fact, they provide more information,
because *Note `mysql_eof()': mysql-eof. returns only a boolean value
whereas the error functions indicate a reason for the error when one
occurs.)

* Return Values *

Zero if no error occurred. Nonzero if the end of the result set has
been reached.

* Errors *

None.

* Example *

The following example shows how you might use *Note `mysql_eof()':
mysql-eof.:

     mysql_query(&mysql,"SELECT * FROM some_table");
     result = mysql_use_result(&mysql);
     while((row = mysql_fetch_row(result)))
     {
         // do something with data
     }
     if(!mysql_eof(result))  // mysql_fetch_row() failed due to an error
     {
         fprintf(stderr, "Error: %s\n", mysql_error(&mysql));
     }

However, you can achieve the same effect with the standard MySQL error
functions:

     mysql_query(&mysql,"SELECT * FROM some_table");
     result = mysql_use_result(&mysql);
     while((row = mysql_fetch_row(result)))
     {
         // do something with data
     }
     if(mysql_errno(&mysql))  // mysql_fetch_row() failed due to an error
     {
         fprintf(stderr, "Error: %s\n", mysql_error(&mysql));
     }


File: manual.info,  Node: mysql-errno,  Next: mysql-error,  Prev: mysql-eof,  Up: c-api-functions

20.8.3.14 `mysql_errno()'
.........................

`unsigned int mysql_errno(MYSQL *mysql)'

* Description *

For the connection specified by `mysql', *Note `mysql_errno()':
mysql-errno. returns the error code for the most recently invoked API
function that can succeed or fail. A return value of zero means that no
error occurred.  Client error message numbers are listed in the MySQL
`errmsg.h' header file. Server error message numbers are listed in
`mysqld_error.h'.  Errors also are listed at *Note error-handling::.

Note that some functions like *Note `mysql_fetch_row()':
mysql-fetch-row. don't set *Note `mysql_errno()': mysql-errno. if they
succeed.

A rule of thumb is that all functions that have to ask the server for
information reset *Note `mysql_errno()': mysql-errno. if they succeed.

MySQL-specific error numbers returned by *Note `mysql_errno()':
mysql-errno. differ from SQLSTATE values returned by *Note
`mysql_sqlstate()': mysql-sqlstate. For example, the *Note `mysql':
mysql. client program displays errors using the following format, where
`1146' is the *Note `mysql_errno()': mysql-errno. value and `'42S02''
is the corresponding *Note `mysql_sqlstate()': mysql-sqlstate. value:

     shell> SELECT * FROM no_such_table;
     ERROR 1146 (42S02): Table 'test.no_such_table' doesn't exist

* Return Values *

An error code value for the last `mysql_XXX()' call, if it failed. zero
means no error occurred.

* Errors *

None.


File: manual.info,  Node: mysql-error,  Next: mysql-escape-string,  Prev: mysql-errno,  Up: c-api-functions

20.8.3.15 `mysql_error()'
.........................

`const char *mysql_error(MYSQL *mysql)'

* Description *

For the connection specified by `mysql', *Note `mysql_error()':
mysql-error. returns a null-terminated string containing the error
message for the most recently invoked API function that failed. If a
function didn't fail, the return value of *Note `mysql_error()':
mysql-error. may be the previous error or an empty string to indicate
no error.

A rule of thumb is that all functions that have to ask the server for
information reset *Note `mysql_error()': mysql-error. if they succeed.

For functions that reset *Note `mysql_error()': mysql-error, the
following two tests are equivalent:

     if(*mysql_error(&mysql))
     {
       // an error occurred
     }

     if(mysql_error(&mysql)[0])
     {
       // an error occurred
     }

The language of the client error messages may be changed by recompiling
the MySQL client library. Currently, you can choose error messages in
several different languages. See *Note error-message-language::.

* Return Values *

A null-terminated character string that describes the error. An empty
string if no error occurred.

* Errors *

None.


File: manual.info,  Node: mysql-escape-string,  Next: mysql-fetch-field,  Prev: mysql-error,  Up: c-api-functions

20.8.3.16 `mysql_escape_string()'
.................................

You should use *Note `mysql_real_escape_string()':
mysql-real-escape-string.  instead!

This function is identical to *Note `mysql_real_escape_string()':
mysql-real-escape-string.  except that *Note
`mysql_real_escape_string()': mysql-real-escape-string. takes a
connection handler as its first argument and escapes the string
according to the current character set.  *Note `mysql_escape_string()':
mysql-escape-string. does not take a connection argument and does not
respect the current character set.


File: manual.info,  Node: mysql-fetch-field,  Next: mysql-fetch-field-direct,  Prev: mysql-escape-string,  Up: c-api-functions

20.8.3.17 `mysql_fetch_field()'
...............................

`MYSQL_FIELD *mysql_fetch_field(MYSQL_RES *result)'

* Description *

Returns the definition of one column of a result set as a `MYSQL_FIELD'
structure. Call this function repeatedly to retrieve information about
all columns in the result set. *Note `mysql_fetch_field()':
mysql-fetch-field.  returns `NULL' when no more fields are left.

*Note `mysql_fetch_field()': mysql-fetch-field. is reset to return
information about the first field each time you execute a new *Note
`SELECT': select. query. The field returned by *Note
`mysql_fetch_field()': mysql-fetch-field.  is also affected by calls to
*Note `mysql_field_seek()': mysql-field-seek.

If you've called *Note `mysql_query()': mysql-query.  to perform a
*Note `SELECT': select. on a table but have not called *Note
`mysql_store_result()': mysql-store-result, MySQL returns the default
blob length (8KB) if you call *Note `mysql_fetch_field()':
mysql-fetch-field. to ask for the length of a *Note `BLOB': blob.
field. (The 8KB size is chosen because MySQL doesn't know the maximum
length for the *Note `BLOB': blob. This should be made configurable
sometime.) Once you've retrieved the result set, `field->max_length'
contains the length of the largest value for this column in the
specific query.

* Return Values *

The `MYSQL_FIELD' structure for the current column. `NULL' if no
columns are left.

* Errors *

None.

* Example *

     MYSQL_FIELD *field;

     while((field = mysql_fetch_field(result)))
     {
         printf("field name %s\n", field->name);
     }


File: manual.info,  Node: mysql-fetch-field-direct,  Next: mysql-fetch-fields,  Prev: mysql-fetch-field,  Up: c-api-functions

20.8.3.18 `mysql_fetch_field_direct()'
......................................

`MYSQL_FIELD *mysql_fetch_field_direct(MYSQL_RES *result, unsigned int
fieldnr)'

* Description *

Given a field number `fieldnr' for a column within a result set,
returns that column's field definition as a `MYSQL_FIELD' structure.
You may use this function to retrieve the definition for an arbitrary
column. The value of `fieldnr' should be in the range from 0 to *Note
`mysql_num_fields(result)-1': mysql-num-fields.

* Return Values *

The `MYSQL_FIELD' structure for the specified column.

* Errors *

None.

* Example *

     unsigned int num_fields;
     unsigned int i;
     MYSQL_FIELD *field;

     num_fields = mysql_num_fields(result);
     for(i = 0; i < num_fields; i++)
     {
         field = mysql_fetch_field_direct(result, i);
         printf("Field %u is %s\n", i, field->name);
     }


File: manual.info,  Node: mysql-fetch-fields,  Next: mysql-fetch-lengths,  Prev: mysql-fetch-field-direct,  Up: c-api-functions

20.8.3.19 `mysql_fetch_fields()'
................................

`MYSQL_FIELD *mysql_fetch_fields(MYSQL_RES *result)'

* Description *

Returns an array of all `MYSQL_FIELD' structures for a result set. Each
structure provides the field definition for one column of the result
set.

* Return Values *

An array of `MYSQL_FIELD' structures for all columns of a result set.

* Errors *

None.

* Example *

     unsigned int num_fields;
     unsigned int i;
     MYSQL_FIELD *fields;

     num_fields = mysql_num_fields(result);
     fields = mysql_fetch_fields(result);
     for(i = 0; i < num_fields; i++)
     {
        printf("Field %u is %s\n", i, fields[i].name);
     }


File: manual.info,  Node: mysql-fetch-lengths,  Next: mysql-fetch-row,  Prev: mysql-fetch-fields,  Up: c-api-functions

20.8.3.20 `mysql_fetch_lengths()'
.................................

`unsigned long *mysql_fetch_lengths(MYSQL_RES *result)'

* Description *

Returns the lengths of the columns of the current row within a result
set. If you plan to copy field values, this length information is also
useful for optimization, because you can avoid calling `strlen()'. In
addition, if the result set contains binary data, you *must* use this
function to determine the size of the data, because `strlen()' returns
incorrect results for any field containing null characters.

The length for empty columns and for columns containing `NULL' values
is zero. To see how to distinguish these two cases, see the description
for *Note `mysql_fetch_row()': mysql-fetch-row.

* Return Values *

An array of unsigned long integers representing the size of each column
(not including any terminating null characters).  `NULL' if an error
occurred.

* Errors *

*Note `mysql_fetch_lengths()': mysql-fetch-lengths. is valid only for
the current row of the result set. It returns `NULL' if you call it
before calling *Note `mysql_fetch_row()': mysql-fetch-row. or after
retrieving all rows in the result.

* Example *

     MYSQL_ROW row;
     unsigned long *lengths;
     unsigned int num_fields;
     unsigned int i;

     row = mysql_fetch_row(result);
     if (row)
     {
         num_fields = mysql_num_fields(result);
         lengths = mysql_fetch_lengths(result);
         for(i = 0; i < num_fields; i++)
         {
              printf("Column %u is %lu bytes in length.\n",
                     i, lengths[i]);
         }
     }


File: manual.info,  Node: mysql-fetch-row,  Next: mysql-field-count,  Prev: mysql-fetch-lengths,  Up: c-api-functions

20.8.3.21 `mysql_fetch_row()'
.............................

`MYSQL_ROW mysql_fetch_row(MYSQL_RES *result)'

* Description *

Retrieves the next row of a result set. When used after *Note
`mysql_store_result()': mysql-store-result, *Note `mysql_fetch_row()':
mysql-fetch-row. returns `NULL' when there are no more rows to retrieve.
When used after *Note `mysql_use_result()': mysql-use-result, *Note
`mysql_fetch_row()': mysql-fetch-row. returns `NULL' when there are no
more rows to retrieve or if an error occurred.

The number of values in the row is given by *Note
`mysql_num_fields(result)': mysql-num-fields. If `row' holds the return
value from a call to *Note `mysql_fetch_row()': mysql-fetch-row,
pointers to the values are accessed as `row[0]' to
`row[mysql_num_fields(result)-1]'.  `NULL' values in the row are
indicated by `NULL' pointers.

The lengths of the field values in the row may be obtained by calling
*Note `mysql_fetch_lengths()': mysql-fetch-lengths.  Empty fields and
fields containing `NULL' both have length 0; you can distinguish these
by checking the pointer for the field value. If the pointer is `NULL',
the field is `NULL'; otherwise, the field is empty.

* Return Values *

A `MYSQL_ROW' structure for the next row.  `NULL' if there are no more
rows to retrieve or if an error occurred.

* Errors *

Note that error is not reset between calls to *Note
`mysql_fetch_row()': mysql-fetch-row.

   * `CR_SERVER_LOST'

     The connection to the server was lost during the query.

   * `CR_UNKNOWN_ERROR'

     An unknown error occurred.

* Example *

     MYSQL_ROW row;
     unsigned int num_fields;
     unsigned int i;

     num_fields = mysql_num_fields(result);
     while ((row = mysql_fetch_row(result)))
     {
        unsigned long *lengths;
        lengths = mysql_fetch_lengths(result);
        for(i = 0; i < num_fields; i++)
        {
            printf("[%.*s] ", (int) lengths[i],
                   row[i] ? row[i] : "NULL");
        }
        printf("\n");
     }


File: manual.info,  Node: mysql-field-count,  Next: mysql-field-seek,  Prev: mysql-fetch-row,  Up: c-api-functions

20.8.3.22 `mysql_field_count()'
...............................

`unsigned int mysql_field_count(MYSQL *mysql)'

* Description *

Returns the number of columns for the most recent query on the
connection.

The normal use of this function is when *Note `mysql_store_result()':
mysql-store-result. returned `NULL' (and thus you have no result set
pointer). In this case, you can call *Note `mysql_field_count()':
mysql-field-count. to determine whether *Note `mysql_store_result()':
mysql-store-result.  should have produced a nonempty result. This
enables the client program to take proper action without knowing
whether the query was a *Note `SELECT': select. (or *Note `SELECT':
select.-like) statement. The example shown here illustrates how this
may be done.

See *Note null-mysql-store-result::.

* Return Values *

An unsigned integer representing the number of columns in a result set.

* Errors *

None.

* Example *

     MYSQL_RES *result;
     unsigned int num_fields;
     unsigned int num_rows;

     if (mysql_query(&mysql,query_string))
     {
         // error
     }
     else // query succeeded, process any data returned by it
     {
         result = mysql_store_result(&mysql);
         if (result)  // there are rows
         {
             num_fields = mysql_num_fields(result);
             // retrieve rows, then call mysql_free_result(result)
         }
         else  // mysql_store_result() returned nothing; should it have?
         {
             if(mysql_field_count(&mysql) == 0)
             {
                 // query does not return data
                 // (it was not a SELECT)
                 num_rows = mysql_affected_rows(&mysql);
             }
             else // mysql_store_result() should have returned data
             {
                 fprintf(stderr, "Error: %s\n", mysql_error(&mysql));
             }
         }
     }

An alternative is to replace the *Note `mysql_field_count(&mysql)':
mysql-field-count.  call with *Note `mysql_errno(&mysql)': mysql-errno.
In this case, you are checking directly for an error from *Note
`mysql_store_result()': mysql-store-result. rather than inferring from
the value of *Note `mysql_field_count()': mysql-field-count. whether the
statement was a *Note `SELECT': select.


File: manual.info,  Node: mysql-field-seek,  Next: mysql-field-tell,  Prev: mysql-field-count,  Up: c-api-functions

20.8.3.23 `mysql_field_seek()'
..............................

`MYSQL_FIELD_OFFSET mysql_field_seek(MYSQL_RES *result,
MYSQL_FIELD_OFFSET offset)'

* Description *

Sets the field cursor to the given offset. The next call to *Note
`mysql_fetch_field()': mysql-fetch-field. retrieves the field
definition of the column associated with that offset.

To seek to the beginning of a row, pass an `offset' value of zero.

* Return Values *

The previous value of the field cursor.

* Errors *

None.


File: manual.info,  Node: mysql-field-tell,  Next: mysql-free-result,  Prev: mysql-field-seek,  Up: c-api-functions

20.8.3.24 `mysql_field_tell()'
..............................

`MYSQL_FIELD_OFFSET mysql_field_tell(MYSQL_RES *result)'

* Description *

Returns the position of the field cursor used for the last *Note
`mysql_fetch_field()': mysql-fetch-field. This value can be used as an
argument to *Note `mysql_field_seek()': mysql-field-seek.

* Return Values *

The current offset of the field cursor.

* Errors *

None.


File: manual.info,  Node: mysql-free-result,  Next: mysql-get-character-set-info,  Prev: mysql-field-tell,  Up: c-api-functions

20.8.3.25 `mysql_free_result()'
...............................

`void mysql_free_result(MYSQL_RES *result)'

* Description *

Frees the memory allocated for a result set by *Note
`mysql_store_result()': mysql-store-result, *Note `mysql_use_result()':
mysql-use-result, *Note `mysql_list_dbs()': mysql-list-dbs, and so
forth.  When you are done with a result set, you must free the memory it
uses by calling *Note `mysql_free_result()': mysql-free-result.

Do not attempt to access a result set after freeing it.

* Return Values *

None.

* Errors *

None.


File: manual.info,  Node: mysql-get-character-set-info,  Next: mysql-get-client-info,  Prev: mysql-free-result,  Up: c-api-functions

20.8.3.26 `mysql_get_character_set_info()'
..........................................

`void mysql_get_character_set_info(MYSQL *mysql, MY_CHARSET_INFO *cs)'

* Description *

This function provides information about the default client character
set. The default character set may be changed with the *Note
`mysql_set_character_set()': mysql-set-character-set.  function.

This function was added in MySQL 5.0.10.

* Example *

This example shows the fields that are available in the
`MY_CHARSET_INFO' structure:

     if (!mysql_set_character_set(&mysql, "utf8"))
     {
         MY_CHARSET_INFO cs;
         mysql_get_character_set_info(&mysql, &cs);
         printf("character set information:\n");
         printf("character set+collation number: %d\n", cs.number);
         printf("character set name: %s\n", cs.name);
         printf("collation name: %s\n", cs.csname);
         printf("comment: %s\n", cs.comment);
         printf("directory: %s\n", cs.dir);
         printf("multi byte character min. length: %d\n", cs.mbminlen);
         printf("multi byte character max. length: %d\n", cs.mbmaxlen);
     }


File: manual.info,  Node: mysql-get-client-info,  Next: mysql-get-client-version,  Prev: mysql-get-character-set-info,  Up: c-api-functions

20.8.3.27 `mysql_get_client_info()'
...................................

`const char *mysql_get_client_info(void)'

* Description *

Returns a string that represents the client library version.

* Return Values *

A character string that represents the MySQL client library version.

* Errors *

None.


File: manual.info,  Node: mysql-get-client-version,  Next: mysql-get-host-info,  Prev: mysql-get-client-info,  Up: c-api-functions

20.8.3.28 `mysql_get_client_version()'
......................................

`unsigned long mysql_get_client_version(void)'

* Description *

Returns an integer that represents the client library version.  The
value has the format `XYYZZ' where `X' is the major version, `YY' is
the release level, and `ZZ' is the version number within the release
level. For example, a value of `40102' represents a client library
version of `4.1.2'.

* Return Values *

An integer that represents the MySQL client library version.

* Errors *

None.


File: manual.info,  Node: mysql-get-host-info,  Next: mysql-get-proto-info,  Prev: mysql-get-client-version,  Up: c-api-functions

20.8.3.29 `mysql_get_host_info()'
.................................

`const char *mysql_get_host_info(MYSQL *mysql)'

* Description *

Returns a string describing the type of connection in use, including
the server host name.

* Return Values *

A character string representing the server host name and the connection
type.

* Errors *

None.


File: manual.info,  Node: mysql-get-proto-info,  Next: mysql-get-server-info,  Prev: mysql-get-host-info,  Up: c-api-functions

20.8.3.30 `mysql_get_proto_info()'
..................................

`unsigned int mysql_get_proto_info(MYSQL *mysql)'

* Description *

Returns the protocol version used by current connection.

* Return Values *

An unsigned integer representing the protocol version used by the
current connection.

* Errors *

None.


File: manual.info,  Node: mysql-get-server-info,  Next: mysql-get-server-version,  Prev: mysql-get-proto-info,  Up: c-api-functions

20.8.3.31 `mysql_get_server_info()'
...................................

`const char *mysql_get_server_info(MYSQL *mysql)'

* Description *

Returns a string that represents the server version number.

* Return Values *

A character string that represents the server version number.

* Errors *

None.


File: manual.info,  Node: mysql-get-server-version,  Next: mysql-get-ssl-cipher,  Prev: mysql-get-server-info,  Up: c-api-functions

20.8.3.32 `mysql_get_server_version()'
......................................

`unsigned long mysql_get_server_version(MYSQL *mysql)'

* Description *

Returns the version number of the server as an integer.

* Return Values *

A number that represents the MySQL server version in this format:

     major_version*10000 + minor_version *100 + sub_version

For example, 5.0.12 is returned as 50012.

This function is useful in client programs for quickly determining
whether some version-specific server capability exists.

* Errors *

None.


File: manual.info,  Node: mysql-get-ssl-cipher,  Next: mysql-hex-string,  Prev: mysql-get-server-version,  Up: c-api-functions

20.8.3.33 `mysql_get_ssl_cipher()'
..................................

`const char *mysql_get_ssl_cipher(MYSQL *mysql)'

* Description *

*Note `mysql_get_ssl_cipher()': mysql-get-ssl-cipher. returns the SSL
cipher used for the given connection to the server.  `mysql' is the
connection handler returned from *Note `mysql_init()': mysql-init.

This function was added in MySQL 5.0.23.

* Return Values *

A string naming the SSL cipher used for the connection, or `NULL' if no
cipher is being used.


File: manual.info,  Node: mysql-hex-string,  Next: mysql-info,  Prev: mysql-get-ssl-cipher,  Up: c-api-functions

20.8.3.34 `mysql_hex_string()'
..............................

`unsigned long mysql_hex_string(char *to, const char *from, unsigned
long length)'

* Description *

This function is used to create a legal SQL string that you can use in
an SQL statement. See *Note string-literals::.

The string in `from' is encoded to hexadecimal format, with each
character encoded as two hexadecimal digits.  The result is placed in
`to' and a terminating null byte is appended.

The string pointed to by `from' must be `length' bytes long. You must
allocate the `to' buffer to be at least `length*2+1' bytes long. When
*Note `mysql_hex_string()': mysql-hex-string. returns, the contents of
`to' is a null-terminated string.  The return value is the length of
the encoded string, not including the terminating null character.

The return value can be placed into an SQL statement using either
`0xVALUE' or `X'VALUE'' format.  However, the return value does not
include the `0x' or `X'...''. The caller must supply whichever of those
is desired.

* Example *

     char query[1000],*end;

     end = strmov(query,"INSERT INTO test_table values(");
     end = strmov(end,"0x");
     end += mysql_hex_string(end,"What is this",12);
     end = strmov(end,",0x");
     end += mysql_hex_string(end,"binary data: \0\r\n",16);
     *end++ = ')';

     if (mysql_real_query(&mysql,query,(unsigned int) (end - query)))
     {
        fprintf(stderr, "Failed to insert row, Error: %s\n",
                mysql_error(&mysql));
     }

The `strmov()' function used in the example is included in the
`mysqlclient' library and works like `strcpy()' but returns a pointer
to the terminating null of the first parameter.

* Return Values *

The length of the value placed into `to', not including the terminating
null character.

* Errors *

None.


File: manual.info,  Node: mysql-info,  Next: mysql-init,  Prev: mysql-hex-string,  Up: c-api-functions

20.8.3.35 `mysql_info()'
........................

`const char *mysql_info(MYSQL *mysql)'

* Description *

Retrieves a string providing information about the most recently
executed statement, but only for the statements listed here. For other
statements, *Note `mysql_info()': mysql-info.  returns `NULL'. The
format of the string varies depending on the type of statement, as
described here. The numbers are illustrative only; the string contains
values appropriate for the statement.

   * *Note `INSERT INTO ... SELECT ...': insert-select.

     String format: `Records: 100 Duplicates: 0 Warnings: 0'

   * `INSERT INTO ... VALUES (...),(...),(...)...'

     String format: `Records: 3 Duplicates: 0 Warnings: 0'

   * *Note `LOAD DATA INFILE ...': load-data.

     String format: `Records: 1 Deleted: 0 Skipped: 0 Warnings: 0'

   * *Note `ALTER TABLE': alter-table.

     String format: `Records: 3 Duplicates: 0 Warnings: 0'

   * *Note `UPDATE': update.

     String format: `Rows matched: 40 Changed: 40 Warnings: 0'

Note that *Note `mysql_info()': mysql-info. returns a non-`NULL' value
for *Note `INSERT ... VALUES': insert. only for the multiple-row form
of the statement (that is, only if multiple value lists are specified).

* Return Values *

A character string representing additional information about the most
recently executed statement. `NULL' if no information is available for
the statement.

* Errors *

None.


File: manual.info,  Node: mysql-init,  Next: mysql-insert-id,  Prev: mysql-info,  Up: c-api-functions

20.8.3.36 `mysql_init()'
........................

`MYSQL *mysql_init(MYSQL *mysql)'

* Description *

Allocates or initializes a `MYSQL' object suitable for *Note
`mysql_real_connect()': mysql-real-connect. If `mysql' is a `NULL'
pointer, the function allocates, initializes, and returns a new object.
Otherwise, the object is initialized and the address of the object is
returned. If *Note `mysql_init()': mysql-init. allocates a new object,
it is freed when *Note `mysql_close()': mysql-close. is called to close
the connection.

* Return Values *

An initialized `MYSQL*' handle.  `NULL' if there was insufficient
memory to allocate a new object.

* Errors *

In case of insufficient memory, `NULL' is returned.


File: manual.info,  Node: mysql-insert-id,  Next: mysql-kill,  Prev: mysql-init,  Up: c-api-functions

20.8.3.37 `mysql_insert_id()'
.............................

`my_ulonglong mysql_insert_id(MYSQL *mysql)'

* Description *

Returns the value generated for an `AUTO_INCREMENT' column by the
previous *Note `INSERT': insert. or *Note `UPDATE': update. statement.
Use this function after you have performed an *Note `INSERT': insert.
statement into a table that contains an `AUTO_INCREMENT' field, or have
used *Note `INSERT': insert. or *Note `UPDATE': update. to set a column
value with `LAST_INSERT_ID(EXPR)'.

More precisely, *Note `mysql_insert_id()': mysql-insert-id. is updated
under these conditions:

   * *Note `INSERT': insert. statements that store a value into an
     `AUTO_INCREMENT' column.  This is true whether the value is
     automatically generated by storing the special values `NULL' or
     `0' into the column, or is an explicit nonspecial value.

   * In the case of a multiple-row *Note `INSERT': insert. statement,
     *Note `mysql_insert_id()': mysql-insert-id. returns the _first_
     automatically generated `AUTO_INCREMENT' value; if no such value is
     generated, it returns the _last_ explicit value inserted into the
     `AUTO_INCREMENT' column.

     If no rows are successfully inserted, *Note `mysql_insert_id()':
     mysql-insert-id. returns 0.

   * Starting in MySQL 5.0.54, if an *Note `INSERT ... SELECT':
     insert-select. statement is executed, and no automatically
     generated value is successfully inserted, *Note
     `mysql_insert_id()': mysql-insert-id. returns the ID of the last
     inserted row.

   * *Note `INSERT': insert. statements that generate an
     `AUTO_INCREMENT' value by inserting `LAST_INSERT_ID(EXPR)' into
     any column or by updating any column to `LAST_INSERT_ID(EXPR)'.

   * If the previous statement returned an error, the value of *Note
     `mysql_insert_id()': mysql-insert-id. is undefined.

*Note `mysql_insert_id()': mysql-insert-id. returns `0' if the previous
statement does not use an `AUTO_INCREMENT' value. If you need to save
the value for later, be sure to call *Note `mysql_insert_id()':
mysql-insert-id. immediately after the statement that generates the
value.

The value of *Note `mysql_insert_id()': mysql-insert-id.  is not
affected by statements such as *Note `SELECT': select. that return a
result set.

The value of *Note `mysql_insert_id()': mysql-insert-id.  is affected
only by statements issued within the current client connection. It is
not affected by statements issued by other clients.

The `LAST_INSERT_ID()' SQL function returns the most recently generated
`AUTO_INCREMENT' value, and is not reset between statements because the
value of that function is maintained in the server. Another difference
from *Note `mysql_insert_id()': mysql-insert-id. is that
`LAST_INSERT_ID()' is not updated if you set an `AUTO_INCREMENT' column
to a specific nonspecial value. See *Note information-functions::.

*Note `mysql_insert_id()': mysql-insert-id. returns `0' following a
*Note `CALL': call. statement for a stored procedure that generates an
`AUTO_INCREMENT' value because in this case *Note `mysql_insert_id()':
mysql-insert-id. applies to *Note `CALL': call. and not the statement
within the procedure. Within the procedure, you can use
`LAST_INSERT_ID()' at the SQL level to obtain the `AUTO_INCREMENT'
value.

The reason for the differences between `LAST_INSERT_ID()' and *Note
`mysql_insert_id()': mysql-insert-id. is that `LAST_INSERT_ID()' is
made easy to use in scripts while *Note `mysql_insert_id()':
mysql-insert-id. tries to provide more exact information about what
happens to the `AUTO_INCREMENT' column.

* Return Values *

Described in the preceding discussion.

* Errors *

None.


File: manual.info,  Node: mysql-kill,  Next: mysql-library-end,  Prev: mysql-insert-id,  Up: c-api-functions

20.8.3.38 `mysql_kill()'
........................

`int mysql_kill(MYSQL *mysql, unsigned long pid)'

* Description *

Asks the server to kill the thread specified by `pid'.

This function is deprecated. It is preferable to use *Note
`mysql_query()': mysql-query. to issue an SQL *Note `KILL': kill.
statement instead.

* Return Values *

Zero for success. Nonzero if an error occurred.

* Errors *

   * `CR_COMMANDS_OUT_OF_SYNC'

     Commands were executed in an improper order.

   * `CR_SERVER_GONE_ERROR'

     The MySQL server has gone away.

   * `CR_SERVER_LOST'

     The connection to the server was lost during the query.

   * `CR_UNKNOWN_ERROR'

     An unknown error occurred.


File: manual.info,  Node: mysql-library-end,  Next: mysql-library-init,  Prev: mysql-kill,  Up: c-api-functions

20.8.3.39 `mysql_library_end()'
...............................

`void mysql_library_end(void)'

* Description *

This function finalizes the MySQL library. You should call it when you
are done using the library (for example, after disconnecting from the
server). The action taken by the call depends on whether your
application is linked to the MySQL client library or the MySQL embedded
server library. For a client program linked against the
`libmysqlclient' library by using the `-lmysqlclient' flag, *Note
`mysql_library_end()': mysql-library-end. performs some memory
management to clean up. For an embedded server application linked
against the `libmysqld' library by using the `-lmysqld' flag, *Note
`mysql_library_end()': mysql-library-end. shuts down the embedded
server and then cleans up.

For usage information, see *Note c-api-function-overview::, and *Note
mysql-library-init::.

*Note `mysql_library_end()': mysql-library-end. was added in MySQL
5.0.3. For older versions of MySQL, call *Note `mysql_server_end()':
mysql-server-end. instead.


File: manual.info,  Node: mysql-library-init,  Next: mysql-list-dbs,  Prev: mysql-library-end,  Up: c-api-functions

20.8.3.40 `mysql_library_init()'
................................

`int mysql_library_init(int argc, char **argv, char **groups)'

* Description *

This function should be called to initialize the MySQL library before
you call any other MySQL function, whether your application is a
regular client program or uses the embedded server. If the application
uses the embedded server, this call starts the server and initializes
any subsystems (`mysys', `InnoDB', and so forth) that the server uses.

After your application is done using the MySQL library, call *Note
`mysql_library_end()': mysql-library-end. to clean up.  See *Note
mysql-library-end::.

The choice of whether the application operates as a regular client or
uses the embedded server depends on whether you use the
`libmysqlclient' or `libmysqld' library at link time to produce the
final executable. For additional information, see *Note
c-api-function-overview::.

In a nonmulti-threaded environment, the call to *Note
`mysql_library_init()': mysql-library-init. may be omitted, because
*Note `mysql_init()': mysql-init.  will invoke it automatically as
necessary. However, *Note `mysql_library_init()': mysql-library-init.
is not thread-safe in a multi-threaded environment, and thus neither is
*Note `mysql_init()': mysql-init, which calls *Note
`mysql_library_init()': mysql-library-init. You must either call *Note
`mysql_library_init()': mysql-library-init.  prior to spawning any
threads, or else use a mutex to protect the call, whether you invoke
*Note `mysql_library_init()': mysql-library-init. or indirectly through
*Note `mysql_init()': mysql-init.  This should be done prior to any
other client library call.

The `argc' and `argv' arguments are analogous to the arguments to
`main()', and enable passing of options to the embedded server. For
convenience, `argc' may be `0' (zero) if there are no command-line
arguments for the server. This is the usual case for applications
intended for use only as regular (nonembedded) clients, and the call
typically is written as *Note `mysql_library_init(0, NULL, NULL)':
mysql-library-init.

     #include <mysql.h>
     #include <stdlib.h>

     int main(void) {
       if (mysql_library_init(0, NULL, NULL)) {
         fprintf(stderr, "could not initialize MySQL library\n");
         exit(1);
       }

       /* Use any MySQL API functions here */

       mysql_library_end();

       return EXIT_SUCCESS;
     }

When arguments are to be passed (`argc' is greater than `0'), the first
element of `argv' is ignored (it typically contains the program name).
*Note `mysql_library_init()': mysql-library-init. makes a copy of the
arguments so it is safe to destroy `argv' or `groups' after the call.

For embedded applications, if you want to connect to an external server
without starting the embedded server, you have to specify a negative
value for `argc'.

The `groups' argument should be an array of strings that indicate the
groups in option files from which options should be read. See *Note
option-files::. The final entry in the array should be `NULL'. For
convenience, if the `groups' argument itself is `NULL', the `[server]'
and `[embedded]' groups are used by default.

     #include <mysql.h>
     #include <stdlib.h>

     static char *server_args[] = {
       "this_program",       /* this string is not used */
       "--datadir=.",
       "--key_buffer_size=32M"
     };
     static char *server_groups[] = {
       "embedded",
       "server",
       "this_program_SERVER",
       (char *)NULL
     };

     int main(void) {
       if (mysql_library_init(sizeof(server_args) / sizeof(char *),
                             server_args, server_groups)) {
         fprintf(stderr, "could not initialize MySQL library\n");
         exit(1);
       }

       /* Use any MySQL API functions here */

       mysql_library_end();

       return EXIT_SUCCESS;
     }

*Note `mysql_library_init()': mysql-library-init. was added in MySQL
5.0.3. For older versions of MySQL, call *Note `mysql_server_init()':
mysql-server-init. instead.

* Return Values *

Zero if successful. Nonzero if an error occurred.


File: manual.info,  Node: mysql-list-dbs,  Next: mysql-list-fields,  Prev: mysql-library-init,  Up: c-api-functions

20.8.3.41 `mysql_list_dbs()'
............................

`MYSQL_RES *mysql_list_dbs(MYSQL *mysql, const char *wild)'

* Description *

Returns a result set consisting of database names on the server that
match the simple regular expression specified by the `wild' parameter.
`wild' may contain the wildcard characters ``%'' or ``_'', or may be a
`NULL' pointer to match all databases. Calling *Note
`mysql_list_dbs()': mysql-list-dbs. is similar to executing the query
`SHOW DATABASES [LIKE WILD]'.

You must free the result set with *Note `mysql_free_result()':
mysql-free-result.

* Return Values *

A `MYSQL_RES' result set for success.  `NULL' if an error occurred.

* Errors *

   * `CR_COMMANDS_OUT_OF_SYNC'

     Commands were executed in an improper order.

   * `CR_OUT_OF_MEMORY'

     Out of memory.

   * `CR_SERVER_GONE_ERROR'

     The MySQL server has gone away.

   * `CR_SERVER_LOST'

     The connection to the server was lost during the query.

   * `CR_UNKNOWN_ERROR'

     An unknown error occurred.


File: manual.info,  Node: mysql-list-fields,  Next: mysql-list-processes,  Prev: mysql-list-dbs,  Up: c-api-functions

20.8.3.42 `mysql_list_fields()'
...............................

`MYSQL_RES *mysql_list_fields(MYSQL *mysql, const char *table, const
char *wild)'

* Description *

Returns a result set consisting of field names in the given table that
match the simple regular expression specified by the `wild' parameter.
`wild' may contain the wildcard characters ``%'' or ``_'', or may be a
`NULL' pointer to match all fields. Calling *Note
`mysql_list_fields()': mysql-list-fields. is similar to executing the
query `SHOW COLUMNS FROM TBL_NAME [LIKE WILD]'.

It is preferable to use `SHOW COLUMNS FROM TBL_NAME' instead of *Note
`mysql_list_fields()': mysql-list-fields.

You must free the result set with *Note `mysql_free_result()':
mysql-free-result.

* Return Values *

A `MYSQL_RES' result set for success.  `NULL' if an error occurred.

* Errors *

   * `CR_COMMANDS_OUT_OF_SYNC'

     Commands were executed in an improper order.

   * `CR_SERVER_GONE_ERROR'

     The MySQL server has gone away.

   * `CR_SERVER_LOST'

     The connection to the server was lost during the query.

   * `CR_UNKNOWN_ERROR'

     An unknown error occurred.


File: manual.info,  Node: mysql-list-processes,  Next: mysql-list-tables,  Prev: mysql-list-fields,  Up: c-api-functions

20.8.3.43 `mysql_list_processes()'
..................................

`MYSQL_RES *mysql_list_processes(MYSQL *mysql)'

* Description *

Returns a result set describing the current server threads. This is the
same kind of information as that reported by *Note `mysqladmin
processlist': mysqladmin. or a *Note `SHOW PROCESSLIST':
show-processlist. query.

You must free the result set with *Note `mysql_free_result()':
mysql-free-result.

* Return Values *

A `MYSQL_RES' result set for success.  `NULL' if an error occurred.

* Errors *

   * `CR_COMMANDS_OUT_OF_SYNC'

     Commands were executed in an improper order.

   * `CR_SERVER_GONE_ERROR'

     The MySQL server has gone away.

   * `CR_SERVER_LOST'

     The connection to the server was lost during the query.

   * `CR_UNKNOWN_ERROR'

     An unknown error occurred.


File: manual.info,  Node: mysql-list-tables,  Next: mysql-more-results,  Prev: mysql-list-processes,  Up: c-api-functions

20.8.3.44 `mysql_list_tables()'
...............................

`MYSQL_RES *mysql_list_tables(MYSQL *mysql, const char *wild)'

* Description *

Returns a result set consisting of table names in the current database
that match the simple regular expression specified by the `wild'
parameter. `wild' may contain the wildcard characters ``%'' or ``_'',
or may be a `NULL' pointer to match all tables. Calling *Note
`mysql_list_tables()': mysql-list-tables. is similar to executing the
query `SHOW TABLES [LIKE WILD]'.

You must free the result set with *Note `mysql_free_result()':
mysql-free-result.

* Return Values *

A `MYSQL_RES' result set for success.  `NULL' if an error occurred.

* Errors *

   * `CR_COMMANDS_OUT_OF_SYNC'

     Commands were executed in an improper order.

   * `CR_SERVER_GONE_ERROR'

     The MySQL server has gone away.

   * `CR_SERVER_LOST'

     The connection to the server was lost during the query.

   * `CR_UNKNOWN_ERROR'

     An unknown error occurred.


File: manual.info,  Node: mysql-more-results,  Next: mysql-next-result,  Prev: mysql-list-tables,  Up: c-api-functions

20.8.3.45 `mysql_more_results()'
................................

`my_bool mysql_more_results(MYSQL *mysql)'

* Description *

This function is used when you execute multiple statements specified as
a single statement string, or when you execute *Note `CALL': call.
statements, which can return multiple result sets.

*Note `mysql_more_results()': mysql-more-results. true if more results
exist from the currently executed statement, in which case the
application must call *Note `mysql_next_result()': mysql-next-result.
to fetch the results.

* Return Values *

`TRUE' (1) if more results exist.  `FALSE' (0) if no more results exist.

In most cases, you can call *Note `mysql_next_result()':
mysql-next-result. instead to test whether more results exist and
initiate retrieval if so.

See *Note c-api-multiple-queries::, and *Note mysql-next-result::.

* Errors *

None.


File: manual.info,  Node: mysql-next-result,  Next: mysql-num-fields,  Prev: mysql-more-results,  Up: c-api-functions

20.8.3.46 `mysql_next_result()'
...............................

`int mysql_next_result(MYSQL *mysql)'

* Description *

This function is used when you execute multiple statements specified as
a single statement string, or when you use *Note `CALL': call.
statements to execute stored procedures, which can return multiple
result sets.

*Note `mysql_next_result()': mysql-next-result. reads the next
statement result and returns a status to indicate whether more results
exist. If *Note `mysql_next_result()': mysql-next-result. returns an
error, there are no more results.

Before each call to *Note `mysql_next_result()': mysql-next-result, you
must call *Note `mysql_free_result()': mysql-free-result. for the
current statement if it is a statement that returned a result set
(rather than just a result status).

After calling *Note `mysql_next_result()': mysql-next-result. the state
of the connection is as if you had called *Note `mysql_real_query()':
mysql-real-query. or *Note `mysql_query()': mysql-query. for the next
statement. This means that you can call *Note `mysql_store_result()':
mysql-store-result, *Note `mysql_warning_count()': mysql-warning-count,
*Note `mysql_affected_rows()': mysql-affected-rows, and so forth.

If your program uses *Note `CALL': call.  statements to execute stored
procedures, the `CLIENT_MULTI_RESULTS' flag must be enabled.  This is
because each *Note `CALL': call. returns a result to indicate the call
status, in addition to any result sets that might be returned by
statements executed within the procedure. Because *Note `CALL': call.
can return multiple results, you should process them using a loop that
calls *Note `mysql_next_result()': mysql-next-result.  to determine
whether there are more results.

`CLIENT_MULTI_RESULTS' can be enabled when you call *Note
`mysql_real_connect()': mysql-real-connect, either explicitly by
passing the `CLIENT_MULTI_RESULTS' flag itself, or implicitly by
passing `CLIENT_MULTI_STATEMENTS' (which also enables
`CLIENT_MULTI_RESULTS').

It is also possible to test whether there are more results by calling
*Note `mysql_more_results()': mysql-more-results.  However, this
function does not change the connection state, so if it returns true,
you must still call *Note `mysql_next_result()': mysql-next-result. to
advance to the next result.

For an example that shows how to use *Note `mysql_next_result()':
mysql-next-result, see *Note c-api-multiple-queries::.

* Return Values *

Return Value              Description
0                         Successful and there are more results
-1                        Successful and there are no more results
>0                        An error occurred

* Errors *

   * `CR_COMMANDS_OUT_OF_SYNC'

     Commands were executed in an improper order. For example, if you
     didn't call *Note `mysql_use_result()': mysql-use-result. for a
     previous result set.

   * `CR_SERVER_GONE_ERROR'

     The MySQL server has gone away.

   * `CR_SERVER_LOST'

     The connection to the server was lost during the query.

   * `CR_UNKNOWN_ERROR'

     An unknown error occurred.


File: manual.info,  Node: mysql-num-fields,  Next: mysql-num-rows,  Prev: mysql-next-result,  Up: c-api-functions

20.8.3.47 `mysql_num_fields()'
..............................

`unsigned int mysql_num_fields(MYSQL_RES *result)'

To pass a `MYSQL*' argument instead, use `unsigned int
mysql_field_count(MYSQL *mysql)'.

* Description *

Returns the number of columns in a result set.

Note that you can get the number of columns either from a pointer to a
result set or to a connection handle. You would use the connection
handle if *Note `mysql_store_result()': mysql-store-result. or *Note
`mysql_use_result()': mysql-use-result. returned `NULL' (and thus you
have no result set pointer). In this case, you can call *Note
`mysql_field_count()': mysql-field-count. to determine whether *Note
`mysql_store_result()': mysql-store-result.  should have produced a
nonempty result. This enables the client program to take proper action
without knowing whether the query was a *Note `SELECT': select. (or
*Note `SELECT': select.-like) statement. The example shown here
illustrates how this may be done.

See *Note null-mysql-store-result::.

* Return Values *

An unsigned integer representing the number of columns in a result set.

* Errors *

None.

* Example *

     MYSQL_RES *result;
     unsigned int num_fields;
     unsigned int num_rows;

     if (mysql_query(&mysql,query_string))
     {
         // error
     }
     else // query succeeded, process any data returned by it
     {
         result = mysql_store_result(&mysql);
         if (result)  // there are rows
         {
             num_fields = mysql_num_fields(result);
             // retrieve rows, then call mysql_free_result(result)
         }
         else  // mysql_store_result() returned nothing; should it have?
         {
             if (mysql_errno(&mysql))
             {
                fprintf(stderr, "Error: %s\n", mysql_error(&mysql));
             }
             else if (mysql_field_count(&mysql) == 0)
             {
                 // query does not return data
                 // (it was not a SELECT)
                 num_rows = mysql_affected_rows(&mysql);
             }
         }
     }

An alternative (if you know that your query should have returned a
result set) is to replace the *Note `mysql_errno(&mysql)': mysql-errno.
call with a check whether *Note `mysql_field_count(&mysql)':
mysql-field-count.  returns 0. This happens only if something went
wrong.


File: manual.info,  Node: mysql-num-rows,  Next: mysql-options,  Prev: mysql-num-fields,  Up: c-api-functions

20.8.3.48 `mysql_num_rows()'
............................

`my_ulonglong mysql_num_rows(MYSQL_RES *result)'

* Description *

Returns the number of rows in the result set.

The use of *Note `mysql_num_rows()': mysql-num-rows.  depends on
whether you use *Note `mysql_store_result()': mysql-store-result. or
*Note `mysql_use_result()': mysql-use-result. to return the result set.
If you use *Note `mysql_store_result()': mysql-store-result, *Note
`mysql_num_rows()': mysql-num-rows. may be called immediately. If you
use *Note `mysql_use_result()': mysql-use-result, *Note
`mysql_num_rows()': mysql-num-rows. does not return the correct value
until all the rows in the result set have been retrieved.

*Note `mysql_num_rows()': mysql-num-rows. is intended for use with
statements that return a result set, such as *Note `SELECT': select.
For statements such as *Note `INSERT': insert, *Note `UPDATE': update,
or *Note `DELETE': delete, the number of affected rows can be obtained
with *Note `mysql_affected_rows()': mysql-affected-rows.

* Return Values *

The number of rows in the result set.

* Errors *

None.


File: manual.info,  Node: mysql-options,  Next: mysql-ping,  Prev: mysql-num-rows,  Up: c-api-functions

20.8.3.49 `mysql_options()'
...........................

`int mysql_options(MYSQL *mysql, enum mysql_option option, const char
*arg)'

* Description *

Can be used to set extra connect options and affect behavior for a
connection. This function may be called multiple times to set several
options.

*Note `mysql_options()': mysql-options. should be called after *Note
`mysql_init()': mysql-init. and before *Note `mysql_connect()':
mysql-connect. or *Note `mysql_real_connect()': mysql-real-connect.

The `option' argument is the option that you want to set; the `arg'
argument is the value for the option. If the option is an integer,
`arg' should point to the value of the integer.

The following list describes the possible options, their effect, and
how `arg' is used for each option. Several of the options apply only
when the application is linked against the `libmysqld' embedded server
library and are unused for applications linked against the `libmysql'
client library. For option descriptions that indicate `arg' is unused,
its value is irrelevant; it is conventional to pass 0.

   * `MYSQL_INIT_COMMAND' (argument type: `char *')

     SQL statement to execute when connecting to the MySQL server.
     Automatically re-executed if reconnection occurs.

   * `MYSQL_OPT_COMPRESS' (argument: not used)

     Use the compressed client/server protocol.

   * `MYSQL_OPT_CONNECT_TIMEOUT' (argument type: `unsigned int *')

     Connect timeout in seconds.

   * `MYSQL_OPT_GUESS_CONNECTION' (argument: not used)

     For an application linked against the `libmysqld' embedded server
     library, this enables the library to guess whether to use the
     embedded server or a remote server. `Guess' means that if the host
     name is set and is not `localhost', it uses a remote server. This
     behavior is the default.  `MYSQL_OPT_USE_EMBEDDED_CONNECTION' and
     `MYSQL_OPT_USE_REMOTE_CONNECTION' can be used to override it. This
     option is ignored for applications linked against the
     `libmysqlclient' client library.

   * `MYSQL_OPT_LOCAL_INFILE' (argument type: optional pointer to
     `unsigned int')

     If no pointer is given or if pointer points to an `unsigned int'
     that has a nonzero value, the `LOAD LOCAL INFILE' statement is
     enabled.

   * `MYSQL_OPT_NAMED_PIPE' (argument: not used)

     Use named pipes to connect to a MySQL server on Windows, if the
     server permits named-pipe connections.

   * `MYSQL_OPT_PROTOCOL' (argument type: `unsigned int *')

     Type of protocol to use. Should be one of the enum values of
     `mysql_protocol_type' defined in `mysql.h'.

   * `MYSQL_OPT_READ_TIMEOUT' (argument type: `unsigned int *')

     The timeout in seconds for attempts to read from the server.  Each
     attempt uses this timeout value and there are retries if
     necessary, so the total effective timeout value is three times the
     option value. You can set the value so that a lost connection can
     be detected earlier than the TCP/IP `Close_Wait_Timeout' value of
     10 minutes.  This option works only for TCP/IP connections and,
     prior to MySQL 5.0.25, only for Windows.

   * `MYSQL_OPT_RECONNECT' (argument type: `my_bool *')

     Enable or disable automatic reconnection to the server if the
     connection is found to have been lost. Reconnect has been off by
     default since MySQL 5.0.3; this option is new in 5.0.13 and
     provides a way to set reconnection behavior explicitly.

     Note: *Note `mysql_real_connect()': mysql-real-connect.
     incorrectly reset the `MYSQL_OPT_RECONNECT' option to its default
     value before MySQL 5.0.19. Therefore, prior to that version, if
     you want reconnect to be enabled for each connection, you must call
     *Note `mysql_options()': mysql-options. with the
     `MYSQL_OPT_RECONNECT' option after each call to *Note
     `mysql_real_connect()': mysql-real-connect. This is not necessary
     as of 5.0.19: Call *Note `mysql_options()': mysql-options. only
     before *Note `mysql_real_connect()': mysql-real-connect. as usual.

   * `MYSQL_SET_CLIENT_IP' (argument type: `char *')

     For an application linked against the `libmysqld' embedded server
     library (when `libmysqld' is compiled with authentication
     support), this means that the user is considered to have connected
     from the specified IP address (specified as a string) for
     authentication purposes. This option is ignored for applications
     linked against the `libmysqlclient' client library.

   * `MYSQL_OPT_SSL_VERIFY_SERVER_CERT' (argument type: `my_bool *')

     Enable or disable verification of the server's Common Name value
     in its certificate against the host name used when connecting to
     the server. The connection is rejected if there is a mismatch.
     This feature can be used to prevent man-in-the-middle attacks.
     Verification is disabled by default. Added in MySQL 5.0.23.

   * `MYSQL_OPT_USE_EMBEDDED_CONNECTION' (argument: not used)

     For an application linked against the `libmysqld' embedded server
     library, this forces the use of the embedded server for the
     connection.  This option is ignored for applications linked
     against the `libmysqlclient' client library.

   * `MYSQL_OPT_USE_REMOTE_CONNECTION' (argument: not used)

     For an application linked against the `libmysqld' embedded server
     library, this forces the use of a remote server for the
     connection. This option is ignored for applications linked against
     the `libmysqlclient' client library.

   * `MYSQL_OPT_USE_RESULT' (argument: not used)

     This option is unused.

   * `MYSQL_OPT_WRITE_TIMEOUT' (argument type: `unsigned int *')

     The timeout in seconds for attempts to write to the server.  Each
     attempt uses this timeout value and there are `net_retry_count'
     retries if necessary, so the total effective timeout value is
     `net_retry_count' times the option value. This option works only
     for TCP/IP connections and, prior to MySQL 5.0.25, only for
     Windows.

   * `MYSQL_READ_DEFAULT_FILE' (argument type: `char *')

     Read options from the named option file instead of from `my.cnf'.

   * `MYSQL_READ_DEFAULT_GROUP' (argument type: `char *')

     Read options from the named group from `my.cnf' or the file
     specified with `MYSQL_READ_DEFAULT_FILE'.

   * `MYSQL_REPORT_DATA_TRUNCATION' (argument type: `my_bool *')

     Enable or disable reporting of data truncation errors for prepared
     statements using the `error' member of `MYSQL_BIND' structures.
     (Default: enabled) Added in 5.0.3.

   * `MYSQL_SECURE_AUTH' (argument type: `my_bool *')

     Whether to connect to a server that does not support the password
     hashing used in MySQL 4.1.1 and later.

   * `MYSQL_SET_CHARSET_DIR' (argument type: `char *')

     The path name to the directory that contains character set
     definition files.

   * `MYSQL_SET_CHARSET_NAME' (argument type: `char *')

     The name of the character set to use as the default character set.

   * `MYSQL_SHARED_MEMORY_BASE_NAME' (argument type: `char *')

     The name of the shared-memory object for communication to the
     server on Windows, if the server supports shared-memory
     connections. Should have the same value as the
     `--shared-memory-base-name' option used for the *Note `mysqld':
     mysqld. server you want to connect to.

The `client' group is always read if you use `MYSQL_READ_DEFAULT_FILE'
or `MYSQL_READ_DEFAULT_GROUP'.

The specified group in the option file may contain the following
options.

Option                    Description
`character-sets-dir=PATH' The directory where character sets are
                          installed.
`compress'                Use the compressed client/server protocol.
`connect-timeout=SECONDS' Connect timeout in seconds. On Linux this
                          timeout is also used for waiting for the first
                          answer from the server.
`database=DB_NAME'        Connect to this database if no database was
                          specified in the connect command.
`debug'                   Debug options.
`default-character-set=CHARSET_NAME'The default character set to use.
`disable-local-infile'    Disable use of *Note `LOAD DATA LOCAL':
                          load-data.
`host=HOST_NAME'          Default host name.
`init-command=STMT'       Statement to execute when connecting to MySQL
                          server. Automatically re-executed if
                          reconnection occurs.
`interactive-timeout=SECONDS'Same as specifying `CLIENT_INTERACTIVE' to
                          *Note `mysql_real_connect()':
                          mysql-real-connect.  See *Note
                          mysql-real-connect::.
`local-infile[={0|1}]'    If no argument or nonzero argument, enable use
                          of *Note `LOAD DATA LOCAL': load-data.;
                          otherwise disable.
`max_allowed_packet=BYTES'Maximum size of packet that client can read
                          from server.
`multi-queries',          Enable multiple result sets from
`multi-results'           multiple-statement executions or stored
                          procedures.
`multi-statements'        Enable the client to send multiple statements
                          in a single string (separated by ``;'').
`password=PASSWORD'       Default password.
`pipe'                    Use named pipes to connect to a MySQL server
                          on Windows.
`port=PORT_NUM'           Default port number.
`protocol={TCP|SOCKET|PIPE|MEMORY}'The protocol to use when connecting to the
                          server.
`return-found-rows'       Tell *Note `mysql_info()': mysql-info. to
                          return found rows instead of updated rows when
                          using *Note `UPDATE': update.
`shared-memory-base-name=NAME'Shared-memory name to use to connect to server.
`socket=PATH'             Default socket file.
`ssl-ca=FILE_NAME'        Certificate Authority file.
`ssl-capath=PATH'         Certificate Authority directory.
`ssl-cert=FILE_NAME'      Certificate file.
`ssl-cipher=CIPHER_LIST'  Permissible SSL ciphers.
`ssl-key=FILE_NAME'       Key file.
`timeout=SECONDS'         Like `connect-timeout'.
`user'                    Default user.

`timeout' has been replaced by `connect-timeout', but `timeout' is
still supported in MySQL 5.0 for backward compatibility.

For more information about option files, see *Note option-files::.

* Return Values *

Zero for success. Nonzero if you specify an unknown option.

* Example *

The following *Note `mysql_options()': mysql-options.  calls request
the use of compression in the client/server protocol, cause options to
be read from the `[odbc]' group of option files, and disable
transaction autocommit mode:

     MYSQL mysql;

     mysql_init(&mysql);
     mysql_options(&mysql,MYSQL_OPT_COMPRESS,0);
     mysql_options(&mysql,MYSQL_READ_DEFAULT_GROUP,"odbc");
     mysql_options(&mysql,MYSQL_INIT_COMMAND,"SET autocommit=0");
     if (!mysql_real_connect(&mysql,"host","user","passwd","database",0,NULL,0))
     {
         fprintf(stderr, "Failed to connect to database: Error: %s\n",
               mysql_error(&mysql));
     }

This code requests that the client use the compressed client/server
protocol and read the additional options from the `odbc' section in the
`my.cnf' file.


File: manual.info,  Node: mysql-ping,  Next: mysql-query,  Prev: mysql-options,  Up: c-api-functions

20.8.3.50 `mysql_ping()'
........................

`int mysql_ping(MYSQL *mysql)'

* Description *

Checks whether the connection to the server is working. If the
connection has gone down and auto-reconnect is enabled an attempt to
reconnect is made. If the connection is down and auto-reconnect is
disabled, *Note `mysql_ping()': mysql-ping. returns an error.

Auto-reconnect is enabled by default before MySQL 5.0.3 and enabled
from 5.0.3 on. To enable auto-connect, call *Note `mysql_options()':
mysql-options. with the `MYSQL_OPT_RECONNECT' option. For details, see
*Note mysql-options::.

*Note `mysql_ping()': mysql-ping. can be used by clients that remain
idle for a long while, to check whether the server has closed the
connection and reconnect if necessary.

If *Note `mysql_ping()': mysql-ping.) does cause a reconnect, there is
no explicit indication of it. To determine whether a reconnect occurs,
call *Note `mysql_thread_id()': mysql-thread-id. to get the original
connection identifier before calling *Note `mysql_ping()': mysql-ping,
then call *Note `mysql_thread_id()': mysql-thread-id. again to see
whether the identifier has changed.

If reconnect occurs, some characteristics of the connection will have
been reset. For details about these characteristics, see *Note
auto-reconnect::.

* Return Values *

Zero if the connection to the server is active. Nonzero if an error
occurred. A nonzero return does not indicate whether the MySQL server
itself is down; the connection might be broken for other reasons such
as network problems.

* Errors *

   * `CR_COMMANDS_OUT_OF_SYNC'

     Commands were executed in an improper order.

   * `CR_SERVER_GONE_ERROR'

     The MySQL server has gone away.

   * `CR_UNKNOWN_ERROR'

     An unknown error occurred.


File: manual.info,  Node: mysql-query,  Next: mysql-real-connect,  Prev: mysql-ping,  Up: c-api-functions

20.8.3.51 `mysql_query()'
.........................

`int mysql_query(MYSQL *mysql, const char *stmt_str)'

* Description *

Executes the SQL statement pointed to by the null-terminated string
`stmt_str'. Normally, the string must consist of a single SQL statement
and you should not add a terminating semicolon (``;'') or `\g' to the
statement. If multiple-statement execution has been enabled, the string
can contain several statements separated by semicolons. See *Note
c-api-multiple-queries::.

*Note `mysql_query()': mysql-query. cannot be used for statements that
contain binary data; you must use *Note `mysql_real_query()':
mysql-real-query. instead.  (Binary data may contain the ``\0''
character, which *Note `mysql_query()': mysql-query. interprets as the
end of the statement string.)

If you want to know whether the statement should return a result set,
you can use *Note `mysql_field_count()': mysql-field-count. to check for
this. See *Note mysql-field-count::.

* Return Values *

Zero if the statement was successful. Nonzero if an error occurred.

* Errors *

   * `CR_COMMANDS_OUT_OF_SYNC'

     Commands were executed in an improper order.

   * `CR_SERVER_GONE_ERROR'

     The MySQL server has gone away.

   * `CR_SERVER_LOST'

     The connection to the server was lost during the query.

   * `CR_UNKNOWN_ERROR'

     An unknown error occurred.


File: manual.info,  Node: mysql-real-connect,  Next: mysql-real-escape-string,  Prev: mysql-query,  Up: c-api-functions

20.8.3.52 `mysql_real_connect()'
................................

`MYSQL *mysql_real_connect(MYSQL *mysql, const char *host, const char
*user, const char *passwd, const char *db, unsigned int port, const
char *unix_socket, unsigned long client_flag)'

* Description *

*Note `mysql_real_connect()': mysql-real-connect. attempts to establish
a connection to a MySQL database engine running on `host'.  *Note
`mysql_real_connect()': mysql-real-connect. must complete successfully
before you can execute any other API functions that require a valid
`MYSQL' connection handle structure.

The parameters are specified as follows:

   * The first parameter should be the address of an existing `MYSQL'
     structure. Before calling *Note `mysql_real_connect()':
     mysql-real-connect. you must call *Note `mysql_init()':
     mysql-init. to initialize the `MYSQL' structure. You can change a
     lot of connect options with the *Note `mysql_options()':
     mysql-options. call. See *Note mysql-options::.

   * The value of `host' may be either a host name or an IP address. If
     `host' is `NULL' or the string `"localhost"', a connection to the
     local host is assumed. For Windows, the client connects using a
     shared-memory connection, if the server has shared-memory
     connections enabled. Otherwise, TCP/IP is used. For Unix, the
     client connects using a Unix socket file. For local connections,
     you can also influence the type of connection to use with the
     `MYSQL_OPT_PROTOCOL' or `MYSQL_OPT_NAMED_PIPE' options to *Note
     `mysql_options()': mysql-options. The type of connection must be
     supported by the server. For a `host' value of `"."' on Windows,
     the client connects using a named pipe, if the server has
     named-pipe connections enabled. If named-pipe connections are not
     enabled, an error occurs.

   * The `user' parameter contains the user's MySQL login ID. If `user'
     is `NULL' or the empty string `""', the current user is assumed.
     Under Unix, this is the current login name. Under Windows ODBC,
     the current user name must be specified explicitly. See the
     Connector/ODBC section of *Note connectors-apis::.

   * The `passwd' parameter contains the password for `user'. If
     `passwd' is `NULL', only entries in the `user' table for the user
     that have a blank (empty) password field are checked for a match.
     This enables the database administrator to set up the MySQL
     privilege system in such a way that users get different privileges
     depending on whether they have specified a password.

     *Note*:

     Do not attempt to encrypt the password before calling *Note
     `mysql_real_connect()': mysql-real-connect.; password encryption
     is handled automatically by the client API.

   * The `user' and `passwd' parameters use whatever character set has
     been configured for the `MYSQL' object. By default, this is
     `latin1', but can be changed by calling *Note
     `mysql_options(mysql, MYSQL_SET_CHARSET_NAME, "CHARSET_NAME")':
     mysql-options. prior to connecting.

   * `db' is the database name. If `db' is not `NULL', the connection
     sets the default database to this value.

   * If `port' is not 0, the value is used as the port number for the
     TCP/IP connection. Note that the `host' parameter determines the
     type of the connection.

   * If `unix_socket' is not `NULL', the string specifies the socket or
     named pipe that should be used. Note that the `host' parameter
     determines the type of the connection.

   * The value of `client_flag' is usually 0, but can be set to a
     combination of the following flags to enable certain features.

     Flag Name               Flag Description
     `CLIENT_COMPRESS'       Use compression protocol.
     `CLIENT_FOUND_ROWS'     Return the number of found (matched) rows,
                             not the number of changed rows.
     `CLIENT_IGNORE_SIGPIPE' Prevents the client library from installing
                             a `SIGPIPE' signal handler. This can be
                             used to avoid conflicts with a handler that
                             the application has already installed.
     `CLIENT_IGNORE_SPACE'   Permit spaces after function names. Makes
                             all functions names reserved words.
     `CLIENT_INTERACTIVE'    Permit `interactive_timeout' seconds
                             (instead of `wait_timeout' seconds) of
                             inactivity before closing the connection.
                             The client's session `wait_timeout'
                             variable is set to the value of the session
                             `interactive_timeout' variable.
     `CLIENT_LOCAL_FILES'    Enable *Note `LOAD DATA LOCAL': load-data.
                             handling.
     `CLIENT_MULTI_RESULTS'  Tell the server that the client can handle
                             multiple result sets from
                             multiple-statement executions or stored
                             procedures.  This flag is automatically
                             enabled if `CLIENT_MULTI_STATEMENTS' is
                             enabled. See the note following this table
                             for more information about this flag.
     `CLIENT_MULTI_STATEMENTS'Tell the server that the client may send
                             multiple statements in a single string
                             (separated by ``;''). If this flag is not
                             set, multiple-statement execution is
                             disabled. See the note following this table
                             for more information about this flag.
     `CLIENT_NO_SCHEMA'      Do not permit the DB_NAME.TBL_NAME.COL_NAME
                             syntax. This is for ODBC. It causes the
                             parser to generate an error if you use that
                             syntax, which is useful for trapping bugs
                             in some ODBC programs.
     `CLIENT_ODBC'           Unused.
     `CLIENT_SSL'            Use SSL (encrypted protocol). This option
                             should not be set by application programs;
                             it is set internally in the client library.
                             Instead, use *Note `mysql_ssl_set()':
                             mysql-ssl-set.  before calling *Note
                             `mysql_real_connect()': mysql-real-connect.
     `CLIENT_REMEMBER_OPTIONS'Remember options specified by calls to
                             *Note `mysql_options()': mysql-options.
                             Without this option, if *Note
                             `mysql_real_connect()': mysql-real-connect.
                             fails, you must repeat the *Note
                             `mysql_options()': mysql-options.  calls
                             before trying to connect again. With this
                             option, the *Note `mysql_options()':
                             mysql-options.  calls need not be repeated.

If your program uses *Note `CALL': call.  statements to execute stored
procedures, the `CLIENT_MULTI_RESULTS' flag must be enabled.  This is
because each *Note `CALL': call. returns a result to indicate the call
status, in addition to any result sets that might be returned by
statements executed within the procedure. Because *Note `CALL': call.
can return multiple results, you should process them using a loop that
calls *Note `mysql_next_result()': mysql-next-result.  to determine
whether there are more results.

`CLIENT_MULTI_RESULTS' can be enabled when you call *Note
`mysql_real_connect()': mysql-real-connect, either explicitly by
passing the `CLIENT_MULTI_RESULTS' flag itself, or implicitly by
passing `CLIENT_MULTI_STATEMENTS' (which also enables
`CLIENT_MULTI_RESULTS').

If you enable `CLIENT_MULTI_STATEMENTS' or `CLIENT_MULTI_RESULTS', you
should process the result for every call to *Note `mysql_query()':
mysql-query. or *Note `mysql_real_query()': mysql-real-query. by using a
loop that calls *Note `mysql_next_result()': mysql-next-result. to
determine whether there are more results. For an example, see *Note
c-api-multiple-queries::.

For some parameters, it is possible to have the value taken from an
option file rather than from an explicit value in the *Note
`mysql_real_connect()': mysql-real-connect. call. To do this, call
*Note `mysql_options()': mysql-options. with the
`MYSQL_READ_DEFAULT_FILE' or `MYSQL_READ_DEFAULT_GROUP' option before
calling *Note `mysql_real_connect()': mysql-real-connect.  Then, in the
*Note `mysql_real_connect()': mysql-real-connect. call, specify the
`no-value' value for each parameter to be read from an option file:

   * For `host', specify a value of `NULL' or the empty string (`""').

   * For `user', specify a value of `NULL' or the empty string.

   * For `passwd', specify a value of `NULL'. (For the password, a
     value of the empty string in the *Note `mysql_real_connect()':
     mysql-real-connect. call cannot be overridden in an option file,
     because the empty string indicates explicitly that the MySQL
     account must have an empty password.)

   * For `db', specify a value of `NULL' or the empty string.

   * For `port', specify a value of 0.

   * For `unix_socket', specify a value of `NULL'.

If no value is found in an option file for a parameter, its default
value is used as indicated in the descriptions given earlier in this
section.

* Return Values *

A `MYSQL*' connection handle if the connection was successful, `NULL'
if the connection was unsuccessful. For a successful connection, the
return value is the same as the value of the first parameter.

* Errors *

   * `CR_CONN_HOST_ERROR'

     Failed to connect to the MySQL server.

   * `CR_CONNECTION_ERROR'

     Failed to connect to the local MySQL server.

   * `CR_IPSOCK_ERROR'

     Failed to create an IP socket.

   * `CR_OUT_OF_MEMORY'

     Out of memory.

   * `CR_SOCKET_CREATE_ERROR'

     Failed to create a Unix socket.

   * `CR_UNKNOWN_HOST'

     Failed to find the IP address for the host name.

   * `CR_VERSION_ERROR'

     A protocol mismatch resulted from attempting to connect to a
     server with a client library that uses a different protocol
     version.

   * `CR_NAMEDPIPEOPEN_ERROR'

     Failed to create a named pipe on Windows.

   * `CR_NAMEDPIPEWAIT_ERROR'

     Failed to wait for a named pipe on Windows.

   * `CR_NAMEDPIPESETSTATE_ERROR'

     Failed to get a pipe handler on Windows.

   * `CR_SERVER_LOST'

     If `connect_timeout' > 0 and it took longer than `connect_timeout'
     seconds to connect to the server or if the server died while
     executing the `init-command'.

* Example *

     MYSQL mysql;

     mysql_init(&mysql);
     mysql_options(&mysql,MYSQL_READ_DEFAULT_GROUP,"your_prog_name");
     if (!mysql_real_connect(&mysql,"host","user","passwd","database",0,NULL,0))
     {
         fprintf(stderr, "Failed to connect to database: Error: %s\n",
               mysql_error(&mysql));
     }

By using *Note `mysql_options()': mysql-options. the MySQL library
reads the `[client]' and `[your_prog_name]' sections in the `my.cnf'
file which ensures that your program works, even if someone has set up
MySQL in some nonstandard way.

Note that upon connection, *Note `mysql_real_connect()':
mysql-real-connect. sets the `reconnect' flag (part of the `MYSQL'
structure) to a value of `1' in versions of the API older than 5.0.3, or
`0' in newer versions. A value of `1' for this flag indicates that if a
statement cannot be performed because of a lost connection, to try
reconnecting to the server before giving up. As of MySQL 5.0.13, you
can use the `MYSQL_OPT_RECONNECT' option to *Note `mysql_options()':
mysql-options. to control reconnection behavior.


File: manual.info,  Node: mysql-real-escape-string,  Next: mysql-real-query,  Prev: mysql-real-connect,  Up: c-api-functions

20.8.3.53 `mysql_real_escape_string()'
......................................

`unsigned long mysql_real_escape_string(MYSQL *mysql, char *to, const
char *from, unsigned long length)'

Note that `mysql' must be a valid, open connection. This is needed
because the escaping depends on the character set in use by the server.

* Description *

This function is used to create a legal SQL string that you can use in
an SQL statement. See *Note string-literals::.

The string in `from' is encoded to an escaped SQL string, taking into
account the current character set of the connection. The result is
placed in `to' and a terminating null byte is appended. Characters
encoded are ``\'', ``''', ``"'', `NUL' (ASCII 0), ``\n'', ``\r'', and
Control+Z. Strictly speaking, MySQL requires only that backslash and
the quote character used to quote the string in the query be escaped.
*Note `mysql_real_escape_string()': mysql-real-escape-string.  quotes
the other characters to make them easier to read in log files. For
comparison, see the quoting rules for literal strings and the `QUOTE()'
SQL function in *Note string-literals::, and *Note string-functions::.

The string pointed to by `from' must be `length' bytes long. You must
allocate the `to' buffer to be at least `length*2+1' bytes long. (In
the worst case, each character may need to be encoded as using two
bytes, and you need room for the terminating null byte.) When *Note
`mysql_real_escape_string()': mysql-real-escape-string.  returns, the
contents of `to' is a null-terminated string. The return value is the
length of the encoded string, not including the terminating null
character.

If you need to change the character set of the connection, you should
use the *Note `mysql_set_character_set()': mysql-set-character-set.
function rather than executing a `SET NAMES' (or `SET CHARACTER SET')
statement.  *Note `mysql_set_character_set()': mysql-set-character-set.
works like `SET NAMES' but also affects the character set used by *Note
`mysql_real_escape_string()': mysql-real-escape-string, which `SET
NAMES' does not.

* Example *

     char query[1000],*end;

     end = strmov(query,"INSERT INTO test_table values(");
     *end++ = '\'';
     end += mysql_real_escape_string(&mysql, end,"What is this",12);
     *end++ = '\'';
     *end++ = ',';
     *end++ = '\'';
     end += mysql_real_escape_string(&mysql, end,"binary data: \0\r\n",16);
     *end++ = '\'';
     *end++ = ')';

     if (mysql_real_query(&mysql,query,(unsigned int) (end - query)))
     {
        fprintf(stderr, "Failed to insert row, Error: %s\n",
                mysql_error(&mysql));
     }

The `strmov()' function used in the example is included in the
`mysqlclient' library and works like `strcpy()' but returns a pointer
to the terminating null of the first parameter.

* Return Values *

The length of the value placed into `to', not including the terminating
null character.

* Errors *

None.


File: manual.info,  Node: mysql-real-query,  Next: mysql-refresh,  Prev: mysql-real-escape-string,  Up: c-api-functions

20.8.3.54 `mysql_real_query()'
..............................

`int mysql_real_query(MYSQL *mysql, const char *stmt_str, unsigned long
length)'

* Description *

Executes the SQL statement pointed to by `stmt_str', which should be a
string `length' bytes long. Normally, the string must consist of a
single SQL statement and you should not add a terminating semicolon
(``;'') or `\g' to the statement. If multiple-statement execution has
been enabled, the string can contain several statements separated by
semicolons. See *Note c-api-multiple-queries::.

*Note `mysql_query()': mysql-query. cannot be used for statements that
contain binary data; you must use *Note `mysql_real_query()':
mysql-real-query. instead.  (Binary data may contain the ``\0''
character, which *Note `mysql_query()': mysql-query. interprets as the
end of the statement string.) In addition, *Note `mysql_real_query()':
mysql-real-query. is faster than *Note `mysql_query()': mysql-query.
because it does not call `strlen()' on the statement string.

If you want to know whether the statement should return a result set,
you can use *Note `mysql_field_count()': mysql-field-count. to check for
this. See *Note mysql-field-count::.

* Return Values *

Zero if the statement was successful. Nonzero if an error occurred.

* Errors *

   * `CR_COMMANDS_OUT_OF_SYNC'

     Commands were executed in an improper order.

   * `CR_SERVER_GONE_ERROR'

     The MySQL server has gone away.

   * `CR_SERVER_LOST'

     The connection to the server was lost during the query.

   * `CR_UNKNOWN_ERROR'

     An unknown error occurred.


File: manual.info,  Node: mysql-refresh,  Next: mysql-reload,  Prev: mysql-real-query,  Up: c-api-functions

20.8.3.55 `mysql_refresh()'
...........................

`int mysql_refresh(MYSQL *mysql, unsigned int options)'

* Description *

This function flushes tables or caches, or resets replication server
information. The connected user must have the `RELOAD' privilege.

The `options' argument is a bit mask composed from any combination of
the following values. Multiple values can be OR'ed together to perform
multiple operations with a single call.

   * `REFRESH_GRANT'

     Refresh the grant tables, like *Note `FLUSH PRIVILEGES': flush.

   * `REFRESH_LOG'

     Flush the logs, like *Note `FLUSH LOGS': flush.

   * `REFRESH_TABLES'

     Flush the table cache, like *Note `FLUSH TABLES': flush.

   * `REFRESH_HOSTS'

     Flush the host cache, like *Note `FLUSH HOSTS': flush.

   * `REFRESH_STATUS'

     Reset status variables, like `FLUSH STATUS'.

   * `REFRESH_THREADS'

     Flush the thread cache.

   * `REFRESH_SLAVE'

     On a slave replication server, reset the master server information
     and restart the slave, like *Note `RESET SLAVE': reset-slave.

   * `REFRESH_MASTER'

     On a master replication server, remove the binary log files listed
     in the binary log index and truncate the index file, like *Note
     `RESET MASTER': reset-master.

* Return Values *

Zero for success. Nonzero if an error occurred.

* Errors *

   * `CR_COMMANDS_OUT_OF_SYNC'

     Commands were executed in an improper order.

   * `CR_SERVER_GONE_ERROR'

     The MySQL server has gone away.

   * `CR_SERVER_LOST'

     The connection to the server was lost during the query.

   * `CR_UNKNOWN_ERROR'

     An unknown error occurred.


File: manual.info,  Node: mysql-reload,  Next: mysql-rollback,  Prev: mysql-refresh,  Up: c-api-functions

20.8.3.56 `mysql_reload()'
..........................

`int mysql_reload(MYSQL *mysql)'

* Description *

Asks the MySQL server to reload the grant tables. The connected user
must have the `RELOAD' privilege.

This function is deprecated. It is preferable to use *Note
`mysql_query()': mysql-query. to issue an SQL *Note `FLUSH PRIVILEGES':
flush. statement instead.

* Return Values *

Zero for success. Nonzero if an error occurred.

* Errors *

   * `CR_COMMANDS_OUT_OF_SYNC'

     Commands were executed in an improper order.

   * `CR_SERVER_GONE_ERROR'

     The MySQL server has gone away.

   * `CR_SERVER_LOST'

     The connection to the server was lost during the query.

   * `CR_UNKNOWN_ERROR'

     An unknown error occurred.


File: manual.info,  Node: mysql-rollback,  Next: mysql-row-seek,  Prev: mysql-reload,  Up: c-api-functions

20.8.3.57 `mysql_rollback()'
............................

`my_bool mysql_rollback(MYSQL *mysql)'

* Description *

Rolls back the current transaction.

As of MySQL 5.0.3, the action of this function is subject to the value
of the `completion_type' system variable. In particular, if the value of
`completion_type' is 2, the server performs a release after terminating
a transaction and closes the client connection. The client program
should call *Note `mysql_close()': mysql-close. to close the connection
from the client side.

* Return Values *

Zero if successful. Nonzero if an error occurred.

* Errors *

None.


File: manual.info,  Node: mysql-row-seek,  Next: mysql-row-tell,  Prev: mysql-rollback,  Up: c-api-functions

20.8.3.58 `mysql_row_seek()'
............................

`MYSQL_ROW_OFFSET mysql_row_seek(MYSQL_RES *result, MYSQL_ROW_OFFSET
offset)'

* Description *

Sets the row cursor to an arbitrary row in a query result set.  The
`offset' value is a row offset that should be a value returned from
*Note `mysql_row_tell()': mysql-row-tell. or from *Note
`mysql_row_seek()': mysql-row-seek. This value is not a row number; if
you want to seek to a row within a result set by number, use *Note
`mysql_data_seek()': mysql-data-seek. instead.

This function requires that the result set structure contains the
entire result of the query, so *Note `mysql_row_seek()':
mysql-row-seek. may be used only in conjunction with *Note
`mysql_store_result()': mysql-store-result, not with *Note
`mysql_use_result()': mysql-use-result.

* Return Values *

The previous value of the row cursor. This value may be passed to a
subsequent call to *Note `mysql_row_seek()': mysql-row-seek.

* Errors *

None.


File: manual.info,  Node: mysql-row-tell,  Next: mysql-select-db,  Prev: mysql-row-seek,  Up: c-api-functions

20.8.3.59 `mysql_row_tell()'
............................

`MYSQL_ROW_OFFSET mysql_row_tell(MYSQL_RES *result)'

* Description *

Returns the current position of the row cursor for the last *Note
`mysql_fetch_row()': mysql-fetch-row. This value can be used as an
argument to *Note `mysql_row_seek()': mysql-row-seek.

You should use *Note `mysql_row_tell()': mysql-row-tell.  only after
*Note `mysql_store_result()': mysql-store-result, not after *Note
`mysql_use_result()': mysql-use-result.

* Return Values *

The current offset of the row cursor.

* Errors *

None.


File: manual.info,  Node: mysql-select-db,  Next: mysql-set-character-set,  Prev: mysql-row-tell,  Up: c-api-functions

20.8.3.60 `mysql_select_db()'
.............................

`int mysql_select_db(MYSQL *mysql, const char *db)'

* Description *

Causes the database specified by `db' to become the default (current)
database on the connection specified by `mysql'. In subsequent queries,
this database is the default for table references that do not include an
explicit database specifier.

*Note `mysql_select_db()': mysql-select-db. fails unless the connected
user can be authenticated as having permission to use the database.

* Return Values *

Zero for success. Nonzero if an error occurred.

* Errors *

   * `CR_COMMANDS_OUT_OF_SYNC'

     Commands were executed in an improper order.

   * `CR_SERVER_GONE_ERROR'

     The MySQL server has gone away.

   * `CR_SERVER_LOST'

     The connection to the server was lost during the query.

   * `CR_UNKNOWN_ERROR'

     An unknown error occurred.


File: manual.info,  Node: mysql-set-character-set,  Next: mysql-set-local-infile-default,  Prev: mysql-select-db,  Up: c-api-functions

20.8.3.61 `mysql_set_character_set()'
.....................................

`int mysql_set_character_set(MYSQL *mysql, const char *csname)'

* Description *

This function is used to set the default character set for the current
connection. The string `csname' specifies a valid character set name.
The connection collation becomes the default collation of the character
set. This function works like the `SET NAMES' statement, but also sets
the value of `mysql->charset', and thus affects the character set used
by *Note `mysql_real_escape_string()': mysql-real-escape-string.

This function was added in MySQL 5.0.7.

* Return Values *

Zero for success. Nonzero if an error occurred.

* Example *

     MYSQL mysql;

     mysql_init(&mysql);
     if (!mysql_real_connect(&mysql,"host","user","passwd","database",0,NULL,0))
     {
         fprintf(stderr, "Failed to connect to database: Error: %s\n",
               mysql_error(&mysql));
     }

     if (!mysql_set_character_set(&mysql, "utf8"))
     {
         printf("New client character set: %s\n",
                mysql_character_set_name(&mysql));
     }


File: manual.info,  Node: mysql-set-local-infile-default,  Next: mysql-set-local-infile-handler,  Prev: mysql-set-character-set,  Up: c-api-functions

20.8.3.62 `mysql_set_local_infile_default()'
............................................

`void mysql_set_local_infile_default(MYSQL *mysql);'

* Description *

Sets the `LOAD LOCAL DATA INFILE' handler callback functions to the
defaults used internally by the C client library. The library calls
this function automatically if *Note
`mysql_set_local_infile_handler()': mysql-set-local-infile-handler.
has not been called or does not supply valid functions for each of its
callbacks.

* Return Values *

None.

* Errors *

None.


File: manual.info,  Node: mysql-set-local-infile-handler,  Next: mysql-set-server-option,  Prev: mysql-set-local-infile-default,  Up: c-api-functions

20.8.3.63 `mysql_set_local_infile_handler()'
............................................

`void mysql_set_local_infile_handler(MYSQL *mysql, int
(*local_infile_init)(void **, const char *, void *), int
(*local_infile_read)(void *, char *, unsigned int), void
(*local_infile_end)(void *), int (*local_infile_error)(void *, char*,
unsigned int), void *userdata);'

* Description *

This function installs callbacks to be used during the execution of
*Note `LOAD DATA LOCAL INFILE': load-data. statements. It enables
application programs to exert control over local (client-side) data
file reading. The arguments are the connection handler, a set of
pointers to callback functions, and a pointer to a data area that the
callbacks can use to share information.

To use *Note `mysql_set_local_infile_handler()':
mysql-set-local-infile-handler, you must write the following callback
functions:

     int
     local_infile_init(void **ptr, const char *filename, void *userdata);

The initialization function. This is called once to do any setup
necessary, open the data file, allocate data structures, and so forth.
The first `void**' argument is a pointer to a pointer. You can set the
pointer (that is, `*ptr') to a value that will be passed to each of the
other callbacks (as a `void*'). The callbacks can use this pointed-to
value to maintain state information. The `userdata' argument is the
same value that is passed to *Note `mysql_set_local_infile_handler()':
mysql-set-local-infile-handler.

The initialization function should return zero for success, nonzero for
an error.

     int
     local_infile_read(void *ptr, char *buf, unsigned int buf_len);

The data-reading function. This is called repeatedly to read the data
file. `buf' points to the buffer where the read data should be stored,
and `buf_len' is the maximum number of bytes that the callback can read
and store in the buffer. (It can read fewer bytes, but should not read
more.)

The return value is the number of bytes read, or zero when no more data
could be read (this indicates EOF). Return a value less than zero if an
error occurs.

     void
     local_infile_end(void *ptr)

The termination function. This is called once after
`local_infile_read()' has returned zero (EOF) or an error. This
function should deallocate any memory allocated by
`local_infile_init()' and perform any other cleanup necessary. It is
invoked even if the initialization function returns an error.

     int
     local_infile_error(void *ptr,
                        char *error_msg,
                        unsigned int error_msg_len);

The error-handling function. This is called to get a textual error
message to return to the user in case any of your other functions
returns an error. `error_msg' points to the buffer into which the
message should be written, and `error_msg_len' is the length of the
buffer.  The message should be written as a null-terminated string, so
the message can be at most `error_msg_len'-1 bytes long.

The return value is the error number.

Typically, the other callbacks store the error message in the data
structure pointed to by `ptr', so that `local_infile_error()' can copy
the message from there into `error_msg'.

After calling *Note `mysql_set_local_infile_handler()':
mysql-set-local-infile-handler.  in your C code and passing pointers to
your callback functions, you can then issue a *Note `LOAD DATA LOCAL
INFILE': load-data. statement (for example, by using *Note
`mysql_query()': mysql-query.). The client library automatically
invokes your callbacks. The file name specified in *Note `LOAD DATA
LOCAL INFILE': load-data. will be passed as the second parameter to the
`local_infile_init()' callback.

* Return Values *

None.

* Errors *

None.


File: manual.info,  Node: mysql-set-server-option,  Next: mysql-shutdown,  Prev: mysql-set-local-infile-handler,  Up: c-api-functions

20.8.3.64 `mysql_set_server_option()'
.....................................

`int mysql_set_server_option(MYSQL *mysql, enum enum_mysql_set_option
option)'

* Description *

Enables or disables an option for the connection.  `option' can have
one of the following values.

Option                               Description
`MYSQL_OPTION_MULTI_STATEMENTS_ON'   Enable multiple-statement support
`MYSQL_OPTION_MULTI_STATEMENTS_OFF'  Disable multiple-statement support

If you enable multiple-statement support, you should retrieve results
from calls to *Note `mysql_query()': mysql-query. or *Note
`mysql_real_query()': mysql-real-query. by using a loop that calls
*Note `mysql_next_result()': mysql-next-result. to determine whether
there are more results. For an example, see *Note
c-api-multiple-queries::.

Enabling multiple-statement support with
`MYSQL_OPTION_MULTI_STATEMENTS_ON' does not have quite the same effect
as enabling it by passing the `CLIENT_MULTI_STATEMENTS' flag to *Note
`mysql_real_connect()': mysql-real-connect.: `CLIENT_MULTI_STATEMENTS'
also enables `CLIENT_MULTI_RESULTS'. If you are using the *Note `CALL':
call. SQL statement in your programs, multiple-result support must be
enabled; this means that `MYSQL_OPTION_MULTI_STATEMENTS_ON' by itself
is insufficient to permit the use of *Note `CALL': call.

* Return Values *

Zero for success. Nonzero if an error occurred.

* Errors *

   * `CR_COMMANDS_OUT_OF_SYNC'

     Commands were executed in an improper order.

   * `CR_SERVER_GONE_ERROR'

     The MySQL server has gone away.

   * `CR_SERVER_LOST'

     The connection to the server was lost during the query.

   * `ER_UNKNOWN_COM_ERROR'

     The server didn't support *Note `mysql_set_server_option()':
     mysql-set-server-option.  (which is the case that the server is
     older than 4.1.1) or the server didn't support the option one
     tried to set.


File: manual.info,  Node: mysql-shutdown,  Next: mysql-sqlstate,  Prev: mysql-set-server-option,  Up: c-api-functions

20.8.3.65 `mysql_shutdown()'
............................

`int mysql_shutdown(MYSQL *mysql, enum mysql_enum_shutdown_level
shutdown_level)'

* Description *

Asks the database server to shut down. The connected user must have the
`SHUTDOWN' privilege. The `shutdown_level' argument was added in MySQL
5.0.1. MySQL 5.0 servers support only one type of shutdown;
`shutdown_level' must be equal to `SHUTDOWN_DEFAULT'. Additional
shutdown levels are planned to make it possible to choose the desired
level.  Dynamically linked executables which have been compiled with
older versions of the `libmysqlclient' headers and call *Note
`mysql_shutdown()': mysql-shutdown. need to be used with the old
`libmysqlclient' dynamic library.

The shutdown process is described in *Note server-shutdown::.

* Return Values *

Zero for success. Nonzero if an error occurred.

* Errors *

   * `CR_COMMANDS_OUT_OF_SYNC'

     Commands were executed in an improper order.

   * `CR_SERVER_GONE_ERROR'

     The MySQL server has gone away.

   * `CR_SERVER_LOST'

     The connection to the server was lost during the query.

   * `CR_UNKNOWN_ERROR'

     An unknown error occurred.


File: manual.info,  Node: mysql-sqlstate,  Next: mysql-ssl-set,  Prev: mysql-shutdown,  Up: c-api-functions

20.8.3.66 `mysql_sqlstate()'
............................

`const char *mysql_sqlstate(MYSQL *mysql)'

* Description *

Returns a null-terminated string containing the SQLSTATE error code for
the most recently executed SQL statement. The error code consists of
five characters. `'00000'' means `no error.' The values are specified
by ANSI SQL and ODBC. For a list of possible values, see *Note
error-handling::.

SQLSTATE values returned by *Note `mysql_sqlstate()': mysql-sqlstate.
differ from MySQL-specific error numbers returned by *Note
`mysql_errno()': mysql-errno. For example, the *Note `mysql': mysql.
client program displays errors using the following format, where `1146'
is the *Note `mysql_errno()': mysql-errno. value and `'42S02'' is the
corresponding *Note `mysql_sqlstate()': mysql-sqlstate. value:

     shell> SELECT * FROM no_such_table;
     ERROR 1146 (42S02): Table 'test.no_such_table' doesn't exist

Not all MySQL error numbers are mapped to SQLSTATE error codes.  The
value `'HY000'' (general error) is used for unmapped error numbers.

If you call *Note `mysql_sqlstate()': mysql-sqlstate.  after *Note
`mysql_real_connect()': mysql-real-connect.  fails, *Note
`mysql_sqlstate()': mysql-sqlstate. might not return a useful value.
For example, this happens if a host is blocked by the server and the
connection is closed without any SQLSTATE value being sent to the
client.

* Return Values *

A null-terminated character string containing the SQLSTATE error code.

* See Also *

See *Note mysql-errno::, *Note mysql-error::, and *Note
mysql-stmt-sqlstate::.


File: manual.info,  Node: mysql-ssl-set,  Next: mysql-stat,  Prev: mysql-sqlstate,  Up: c-api-functions

20.8.3.67 `mysql_ssl_set()'
...........................

`my_bool mysql_ssl_set(MYSQL *mysql, const char *key, const char *cert,
const char *ca, const char *capath, const char *cipher)'

* Description *

*Note `mysql_ssl_set()': mysql-ssl-set. is used for establishing secure
connections using SSL. It must be called before *Note
`mysql_real_connect()': mysql-real-connect.

*Note `mysql_ssl_set()': mysql-ssl-set. does nothing unless SSL support
is enabled in the client library.

`mysql' is the connection handler returned from *Note `mysql_init()':
mysql-init. The other parameters are specified as follows:

   * `key' is the path name to the key file.

   * `cert' is the path name to the certificate file.

   * `ca' is the path name to the certificate authority file.

   * `capath' is the path name to a directory that contains trusted SSL
     CA certificates in pem format.

   * `cipher' is a list of permissible ciphers to use for SSL
     encryption.

Any unused SSL parameters may be given as `NULL'.

* Return Values *

This function always returns `0'. If SSL setup is incorrect, *Note
`mysql_real_connect()': mysql-real-connect. returns an error when you
attempt to connect.


File: manual.info,  Node: mysql-stat,  Next: mysql-store-result,  Prev: mysql-ssl-set,  Up: c-api-functions

20.8.3.68 `mysql_stat()'
........................

`const char *mysql_stat(MYSQL *mysql)'

* Description *

Returns a character string containing information similar to that
provided by the *Note `mysqladmin status': mysqladmin.  command. This
includes uptime in seconds and the number of running threads,
questions, reloads, and open tables.

* Return Values *

A character string describing the server status.  `NULL' if an error
occurred.

* Errors *

   * `CR_COMMANDS_OUT_OF_SYNC'

     Commands were executed in an improper order.

   * `CR_SERVER_GONE_ERROR'

     The MySQL server has gone away.

   * `CR_SERVER_LOST'

     The connection to the server was lost during the query.

   * `CR_UNKNOWN_ERROR'

     An unknown error occurred.


File: manual.info,  Node: mysql-store-result,  Next: mysql-thread-id,  Prev: mysql-stat,  Up: c-api-functions

20.8.3.69 `mysql_store_result()'
................................

`MYSQL_RES *mysql_store_result(MYSQL *mysql)'

* Description *

After invoking *Note `mysql_query()': mysql-query. or *Note
`mysql_real_query()': mysql-real-query, you must call *Note
`mysql_store_result()': mysql-store-result. or *Note
`mysql_use_result()': mysql-use-result. for every statement that
successfully produces a result set (*Note `SELECT': select, *Note
`SHOW': show, *Note `DESCRIBE': describe, *Note `EXPLAIN': explain,
*Note `CHECK TABLE': check-table, and so forth). You must also call
*Note `mysql_free_result()': mysql-free-result. after you are done with
the result set.

You don't have to call *Note `mysql_store_result()':
mysql-store-result. or *Note `mysql_use_result()': mysql-use-result.
for other statements, but it does not do any harm or cause any notable
performance degradation if you call *Note `mysql_store_result()':
mysql-store-result. in all cases. You can detect whether the statement
has a result set by checking whether *Note `mysql_store_result()':
mysql-store-result. returns a nonzero value (more about this later).

If you enable multiple-statement support, you should retrieve results
from calls to *Note `mysql_query()': mysql-query. or *Note
`mysql_real_query()': mysql-real-query. by using a loop that calls
*Note `mysql_next_result()': mysql-next-result. to determine whether
there are more results. For an example, see *Note
c-api-multiple-queries::.

If you want to know whether a statement should return a result set, you
can use *Note `mysql_field_count()': mysql-field-count. to check for
this. See *Note mysql-field-count::.

*Note `mysql_store_result()': mysql-store-result. reads the entire
result of a query to the client, allocates a `MYSQL_RES' structure, and
places the result into this structure.

*Note `mysql_store_result()': mysql-store-result. returns a null
pointer if the statement didn't return a result set (for example, if it
was an *Note `INSERT': insert.  statement).

*Note `mysql_store_result()': mysql-store-result. also returns a null
pointer if reading of the result set failed. You can check whether an
error occurred by checking whether *Note `mysql_error()': mysql-error.
returns a nonempty string, *Note `mysql_errno()': mysql-errno. returns
nonzero, or *Note `mysql_field_count()': mysql-field-count.  returns
zero.

An empty result set is returned if there are no rows returned.  (An
empty result set differs from a null pointer as a return value.)

After you have called *Note `mysql_store_result()': mysql-store-result.
and gotten back a result that isn't a null pointer, you can call *Note
`mysql_num_rows()': mysql-num-rows. to find out how many rows are in
the result set.

You can call *Note `mysql_fetch_row()': mysql-fetch-row.  to fetch rows
from the result set, or *Note `mysql_row_seek()': mysql-row-seek. and
*Note `mysql_row_tell()': mysql-row-tell. to obtain or set the current
row position within the result set.

See *Note null-mysql-store-result::.

* Return Values *

A `MYSQL_RES' result structure with the results. `NULL' (0) if an error
occurred.

* Errors *

*Note `mysql_store_result()': mysql-store-result. resets *Note
`mysql_error()': mysql-error. and *Note `mysql_errno()': mysql-errno.
if it succeeds.

   * `CR_COMMANDS_OUT_OF_SYNC'

     Commands were executed in an improper order.

   * `CR_OUT_OF_MEMORY'

     Out of memory.

   * `CR_SERVER_GONE_ERROR'

     The MySQL server has gone away.

   * `CR_SERVER_LOST'

     The connection to the server was lost during the query.

   * `CR_UNKNOWN_ERROR'

     An unknown error occurred.


File: manual.info,  Node: mysql-thread-id,  Next: mysql-use-result,  Prev: mysql-store-result,  Up: c-api-functions

20.8.3.70 `mysql_thread_id()'
.............................

`unsigned long mysql_thread_id(MYSQL *mysql)'

* Description *

Returns the thread ID of the current connection. This value can be used
as an argument to *Note `mysql_kill()': mysql-kill. to kill the thread.

If the connection is lost and you reconnect with *Note `mysql_ping()':
mysql-ping, the thread ID changes. This means you should not get the
thread ID and store it for later. You should get it when you need it.

* Return Values *

The thread ID of the current connection.

* Errors *

None.


File: manual.info,  Node: mysql-use-result,  Next: mysql-warning-count,  Prev: mysql-thread-id,  Up: c-api-functions

20.8.3.71 `mysql_use_result()'
..............................

`MYSQL_RES *mysql_use_result(MYSQL *mysql)'

* Description *

After invoking *Note `mysql_query()': mysql-query. or *Note
`mysql_real_query()': mysql-real-query, you must call *Note
`mysql_store_result()': mysql-store-result. or *Note
`mysql_use_result()': mysql-use-result. for every statement that
successfully produces a result set (*Note `SELECT': select, *Note
`SHOW': show, *Note `DESCRIBE': describe, *Note `EXPLAIN': explain,
*Note `CHECK TABLE': check-table, and so forth). You must also call
*Note `mysql_free_result()': mysql-free-result. after you are done with
the result set.

*Note `mysql_use_result()': mysql-use-result. initiates a result set
retrieval but does not actually read the result set into the client like
*Note `mysql_store_result()': mysql-store-result. does.  Instead, each
row must be retrieved individually by making calls to *Note
`mysql_fetch_row()': mysql-fetch-row. This reads the result of a query
directly from the server without storing it in a temporary table or
local buffer, which is somewhat faster and uses much less memory than
*Note `mysql_store_result()': mysql-store-result. The client allocates
memory only for the current row and a communication buffer that may
grow up to `max_allowed_packet' bytes.

On the other hand, you shouldn't use *Note `mysql_use_result()':
mysql-use-result. if you are doing a lot of processing for each row on
the client side, or if the output is sent to a screen on which the user
may type a `^S' (stop scroll). This ties up the server and prevent
other threads from updating any tables from which the data is being
fetched.

When using *Note `mysql_use_result()': mysql-use-result, you must
execute *Note `mysql_fetch_row()': mysql-fetch-row. until a `NULL'
value is returned, otherwise, the unfetched rows are returned as part
of the result set for your next query. The C API gives the error
`Commands out of sync; you can't run this command now' if you forget to
do this!

You may not use *Note `mysql_data_seek()': mysql-data-seek, *Note
`mysql_row_seek()': mysql-row-seek, *Note `mysql_row_tell()':
mysql-row-tell, *Note `mysql_num_rows()': mysql-num-rows, or *Note
`mysql_affected_rows()': mysql-affected-rows. with a result returned
from *Note `mysql_use_result()': mysql-use-result, nor may you issue
other queries until *Note `mysql_use_result()': mysql-use-result. has
finished.  (However, after you have fetched all the rows, *Note
`mysql_num_rows()': mysql-num-rows. accurately returns the number of
rows fetched.)

You must call *Note `mysql_free_result()': mysql-free-result. once you
are done with the result set.

When using the `libmysqld' embedded server, the memory benefits are
essentially lost because memory usage incrementally increases with each
row retrieved until *Note `mysql_free_result()': mysql-free-result. is
called.

* Return Values *

A `MYSQL_RES' result structure.  `NULL' if an error occurred.

* Errors *

*Note `mysql_use_result()': mysql-use-result. resets *Note
`mysql_error()': mysql-error. and *Note `mysql_errno()': mysql-errno.
if it succeeds.

   * `CR_COMMANDS_OUT_OF_SYNC'

     Commands were executed in an improper order.

   * `CR_OUT_OF_MEMORY'

     Out of memory.

   * `CR_SERVER_GONE_ERROR'

     The MySQL server has gone away.

   * `CR_SERVER_LOST'

     The connection to the server was lost during the query.

   * `CR_UNKNOWN_ERROR'

     An unknown error occurred.


File: manual.info,  Node: mysql-warning-count,  Prev: mysql-use-result,  Up: c-api-functions

20.8.3.72 `mysql_warning_count()'
.................................

`unsigned int mysql_warning_count(MYSQL *mysql)'

* Description *

Returns the number of errors, warnings, and notes generated during
execution of the previous SQL statement.

* Return Values *

The warning count.

* Errors *

None.


File: manual.info,  Node: c-api-prepared-statements,  Next: c-api-prepared-statement-data-structures,  Prev: c-api-functions,  Up: c

20.8.4 C API Prepared Statements
--------------------------------

The MySQL client/server protocol provides for the use of prepared
statements. This capability uses the `MYSQL_STMT' statement handler
data structure returned by the *Note `mysql_stmt_init()':
mysql-stmt-init. initialization function. Prepared execution is an
efficient way to execute a statement more than once. The statement is
first parsed to prepare it for execution. Then it is executed one or
more times at a later time, using the statement handle returned by the
initialization function.

Prepared execution is faster than direct execution for statements
executed more than once, primarily because the query is parsed only
once. In the case of direct execution, the query is parsed every time
it is executed. Prepared execution also can provide a reduction of
network traffic because for each execution of the prepared statement,
it is necessary only to send the data for the parameters.

Prepared statements might not provide a performance increase in some
situations. For best results, test your application both with prepared
and nonprepared statements and choose whichever yields best performance.

Another advantage of prepared statements is that it uses a binary
protocol that makes data transfer between client and server more
efficient.

The following SQL statements can be used as prepared statements: *Note
`CALL': call, *Note `CREATE TABLE': create-table, *Note `DELETE':
delete, *Note `DO': do, *Note `INSERT': insert, *Note `REPLACE':
replace, *Note `SELECT': select, *Note `SET': set-option, *Note
`UPDATE': update, and most *Note `SHOW': show. statements. Other
statements are not supported in MySQL 5.0.


File: manual.info,  Node: c-api-prepared-statement-data-structures,  Next: c-api-prepared-statement-function-overview,  Prev: c-api-prepared-statements,  Up: c

20.8.5 C API Prepared Statement Data Structures
-----------------------------------------------

* Menu:

* c-api-prepared-statement-type-codes::  C API Prepared Statement Type Codes
* c-api-prepared-statement-type-conversions::  C API Prepared Statement Type Conversions

Prepared statements use several data structures:

   * To obtain a statement handle, pass a `MYSQL' connection handler to
     *Note `mysql_stmt_init()': mysql-stmt-init, which returns a
     pointer to a `MYSQL_STMT' data structure. This structure is used
     for further operations with the statement. To specify the
     statement to prepare, pass the `MYSQL_STMT' pointer and the
     statement string to *Note `mysql_stmt_prepare()':
     mysql-stmt-prepare.

   * To provide input parameters for a prepared statement, set up
     `MYSQL_BIND' structures and pass them to *Note
     `mysql_stmt_bind_param()': mysql-stmt-bind-param. To receive
     output column values, set up `MYSQL_BIND' structures and pass them
     to *Note `mysql_stmt_bind_result()': mysql-stmt-bind-result.

   * The `MYSQL_TIME' structure is used to transfer temporal data in
     both directions.

The following discussion describes the prepared statement data types in
detail. For examples that show how to use them, see *Note
mysql-stmt-execute::, and *Note mysql-stmt-fetch::.

   * `MYSQL_STMT'

     This structure is a handle for a prepared statement. A handle is
     created by calling *Note `mysql_stmt_init()': mysql-stmt-init,
     which returns a pointer to a `MYSQL_STMT'. The handle is used for
     all subsequent operations with the statement until you close it
     with *Note `mysql_stmt_close()': mysql-stmt-close, at which point
     the handle becomes invalid.

     The `MYSQL_STMT' structure has no members intended for application
     use. Applications should not try to copy a `MYSQL_STMT' structure.
     There is no guarantee that such a copy will be usable.

     Multiple statement handles can be associated with a single
     connection. The limit on the number of handles depends on the
     available system resources.

   * `MYSQL_BIND'

     This structure is used both for statement input (data values sent
     to the server) and output (result values returned from the server):

        * For input, use `MYSQL_BIND' structures with *Note
          `mysql_stmt_bind_param()': mysql-stmt-bind-param. to bind
          parameter data values to buffers for use by *Note
          `mysql_stmt_execute()': mysql-stmt-execute.

        * For output, use `MYSQL_BIND' structures with *Note
          `mysql_stmt_bind_result()': mysql-stmt-bind-result.  to bind
          buffers to result set columns, for use in fetching rows with
          *Note `mysql_stmt_fetch()': mysql-stmt-fetch.

     To use a `MYSQL_BIND' structure, zero its contents to initialize
     it, then set its members appropriately.  For example, to declare
     and initialize an array of three `MYSQL_BIND' structures, use this
     code:

          MYSQL_BIND bind[3];
          memset(bind, 0, sizeof(bind));

     The `MYSQL_BIND' structure contains the following members for use
     by application programs. For several of the members, the manner of
     use depends on whether the structure is used for input or output.

        * `enum enum_field_types buffer_type'

          The type of the buffer. This member indicates the data type
          of the C language variable bound to a statement parameter or
          result set column. For input, `buffer_type' indicates the
          type of the variable containing the value to be sent to the
          server.  For output, it indicates the type of the variable
          into which a value received from the server should be stored.
          For permissible `buffer_type' values, see *Note
          c-api-prepared-statement-type-codes::.

        * `void *buffer'

          A pointer to the buffer to be used for data transfer. This is
          the address of a C language variable.

          For input, `buffer' is a pointer to the variable in which you
          store the data value for a statement parameter. When you call
          *Note `mysql_stmt_execute()': mysql-stmt-execute, MySQL use
          the value stored in the variable in place of the
          corresponding parameter marker in the statement (specified
          with `?' in the statement string).

          For output, `buffer' is a pointer to the variable in which to
          return a result set column value.  When you call *Note
          `mysql_stmt_fetch()': mysql-stmt-fetch, MySQL stores a column
          value from the current row of the result set in this
          variable. You can access the value when the call returns.

          To minimize the need for MySQL to perform type conversions
          between C language values on the client side and SQL values
          on the server side, use C variables that have types similar
          to those of the corresponding SQL values:

             * For numeric data types, `buffer' should point to a
               variable of the proper numeric C type. For integer
               variables (which can be `char' for single-byte values or
               an integer type for larger values), you should also
               indicate whether the variable has the `unsigned'
               attribute by setting the `is_unsigned' member, described
               later.

             * For character (nonbinary) and binary string data types,
               `buffer' should point to a character buffer.

             * For date and time data types, `buffer' should point to a
               `MYSQL_TIME' structure.

          For guidelines about mapping between C types and SQL types
          and notes about type conversions, see *Note
          c-api-prepared-statement-type-codes::, and *Note
          c-api-prepared-statement-type-conversions::.

        * `unsigned long buffer_length'

          The actual size of `*buffer' in bytes.  This indicates the
          maximum amount of data that can be stored in the buffer. For
          character and binary C data, the `buffer_length' value
          specifies the length of `*buffer' when used with *Note
          `mysql_stmt_bind_param()': mysql-stmt-bind-param. to specify
          input values, or the maximum number of output data bytes that
          can be fetched into the buffer when used with *Note
          `mysql_stmt_bind_result()': mysql-stmt-bind-result.

        * `unsigned long *length'

          A pointer to an `unsigned long' variable that indicates the
          actual number of bytes of data stored in `*buffer'. `length'
          is used for character or binary C data.

          For input parameter data binding, set `*length' to indicate
          the actual length of the parameter value stored in `*buffer'.
          This is used by *Note `mysql_stmt_execute()':
          mysql-stmt-execute.

          For output value binding, MySQL sets `*length' when you call
          *Note `mysql_stmt_fetch()': mysql-stmt-fetch. The *Note
          `mysql_stmt_fetch()': mysql-stmt-fetch. return value
          determines how to interpret the length:

             * If the return value is 0, `*length' indicates the actual
               length of the parameter value.

             * If the return value is `MYSQL_DATA_TRUNCATED', `*length'
               indicates the nontruncated length of the parameter
               value. In this case, the minimum of `*length' and
               `buffer_length' indicates the actual length of the value.

          `length' is ignored for numeric and temporal data types
          because the `buffer_type' value determines the length of the
          data value.

          If you must determine the length of a returned value before
          fetching it, see *Note mysql-stmt-fetch::, for some
          strategies.

        * `my_bool *is_null'

          This member points to a `my_bool' variable that is true if a
          value is `NULL', false if it is not `NULL'. For input, set
          `*is_null' to true to indicate that you are passing a `NULL'
          value as a statement parameter.

          `is_null' is a _pointer_ to a boolean scalar, not a boolean
          scalar, to provide flexibility in how you specify `NULL'
          values:

             * If your data values are always `NULL', use
               `MYSQL_TYPE_NULL' as the `buffer_type' value when you
               bind the column. The other `MYSQL_BIND' members,
               including `is_null', do not matter.

             * If your data values are always `NOT NULL', set `is_null
               = (my_bool*) 0', and set the other members appropriately
               for the variable you are binding.

             * In all other cases, set the other members appropriately
               and set `is_null' to the address of a `my_bool' variable.
               Set that variable's value to true or false appropriately
               between executions to indicate whether the corresponding
               data value is `NULL' or `NOT NULL', respectively.

          For output, when you fetch a row, MySQL sets the value
          pointed to by `is_null' to true or false according to whether
          the result set column value returned from the statement is or
          is not `NULL'.

        * `my_bool is_unsigned'

          This member applies for C variables with data types that can
          be `unsigned' (`char', `short int', `int', `long long int').
          Set `is_unsigned' to true if the variable pointed to by
          `buffer' is `unsigned' and false otherwise. For example, if
          you bind a `signed char' variable to `buffer', specify a type
          code of `MYSQL_TYPE_TINY' and set `is_unsigned' to false. If
          you bind an `unsigned char' instead, the type code is the
          same but `is_unsigned' should be true. (For `char', it is not
          defined whether it is signed or unsigned, so it is best to be
          explicit about signedness by using `signed char' or `unsigned
          char'.)

          `is_unsigned' applies only to the C language variable on the
          client side. It indicates nothing about the signedness of the
          corresponding SQL value on the server side. For example, if
          you use an `int' variable to supply a value for a `BIGINT
          UNSIGNED' column, `is_unsigned' should be false because `int'
          is a signed type. If you use an `unsigned int' variable to
          supply a value for a *Note `BIGINT': numeric-types. column,
          `is_unsigned' should be true because `unsigned int' is an
          unsigned type. MySQL performs the proper conversion between
          signed and unsigned values in both directions, although a
          warning occurs if truncation results.

        * `my_bool *error'

          For output, set this member to point to a `my_bool' variable
          to have truncation information for the parameter stored there
          after a row fetching operation. When truncation reporting is
          enabled, *Note `mysql_stmt_fetch()': mysql-stmt-fetch. returns
          `MYSQL_DATA_TRUNCATED' and `*error' is true in the
          `MYSQL_BIND' structures for parameters in which truncation
          occurred. Truncation indicates loss of sign or significant
          digits, or that a string was too long to fit in a column.
          Truncation reporting is enabled by default, but can be
          controlled by calling *Note `mysql_options()': mysql-options.
          with the `MYSQL_REPORT_DATA_TRUNCATION' option.  The `error'
          member was added in MySQL 5.0.3.

   * `MYSQL_TIME'

     This structure is used to send and receive *Note `DATE': datetime,
     *Note `TIME': time, *Note `DATETIME': datetime, and *Note
     `TIMESTAMP': datetime. data directly to and from the server. Set
     the `buffer' member to point to a `MYSQL_TIME' structure, and set
     the `buffer_type' member of a `MYSQL_BIND' structure to one of the
     temporal types (`MYSQL_TYPE_TIME', `MYSQL_TYPE_DATE',
     `MYSQL_TYPE_DATETIME', `MYSQL_TYPE_TIMESTAMP').

     The `MYSQL_TIME' structure contains the members listed in the
     following table.

     Member                      Description
     `unsigned int year'         The year
     `unsigned int month'        The month of the year
     `unsigned int day'          The day of the month
     `unsigned int hour'         The hour of the day
     `unsigned int minute'       The minute of the hour
     `unsigned int second'       The second of the minute
     `my_bool neg'               A boolean flag indicating whether the
                                 time is negative
     `unsigned long second_part' The fractional part of the second in
                                 microseconds; currently unused

     Only those parts of a `MYSQL_TIME' structure that apply to a given
     type of temporal value are used. The `year', `month', and `day'
     elements are used for *Note `DATE': datetime, *Note `DATETIME':
     datetime, and *Note `TIMESTAMP': datetime. values. The `hour',
     `minute', and `second' elements are used for *Note `TIME': time,
     *Note `DATETIME': datetime, and *Note `TIMESTAMP': datetime.
     values. See *Note c-api-prepared-statement-date-handling::.


File: manual.info,  Node: c-api-prepared-statement-type-codes,  Next: c-api-prepared-statement-type-conversions,  Prev: c-api-prepared-statement-data-structures,  Up: c-api-prepared-statement-data-structures

20.8.5.1 C API Prepared Statement Type Codes
............................................

The `buffer_type' member of `MYSQL_BIND' structures indicates the data
type of the C language variable bound to a statement parameter or
result set column. For input, `buffer_type' indicates the type of the
variable containing the value to be sent to the server. For output, it
indicates the type of the variable into which a value received from the
server should be stored.

The following table shows the permissible values for the `buffer_type'
member of `MYSQL_BIND' structures for input values sent to the server.
The table shows the C variable types that you can use, the
corresponding type codes, and the SQL data types for which the supplied
value can be used without conversion. Choose the `buffer_type' value
according to the data type of the C language variable that you are
binding. For the integer types, you should also set the `is_unsigned'
member to indicate whether the variable is signed or unsigned.

Input Variable C Type  `buffer_type' Value       SQL Type of Destination
                                                 Value
`signed char'          `MYSQL_TYPE_TINY'         *Note `TINYINT':
                                                 numeric-types.
`short int'            `MYSQL_TYPE_SHORT'        *Note `SMALLINT':
                                                 numeric-types.
`int'                  `MYSQL_TYPE_LONG'         *Note `INT':
                                                 numeric-types.
`long long int'        `MYSQL_TYPE_LONGLONG'     *Note `BIGINT':
                                                 numeric-types.
`float'                `MYSQL_TYPE_FLOAT'        *Note `FLOAT':
                                                 numeric-types.
`double'               `MYSQL_TYPE_DOUBLE'       *Note `DOUBLE':
                                                 numeric-types.
`MYSQL_TIME'           `MYSQL_TYPE_TIME'         *Note `TIME': time.
`MYSQL_TIME'           `MYSQL_TYPE_DATE'         *Note `DATE': datetime.
`MYSQL_TIME'           `MYSQL_TYPE_DATETIME'     *Note `DATETIME':
                                                 datetime.
`MYSQL_TIME'           `MYSQL_TYPE_TIMESTAMP'    *Note `TIMESTAMP':
                                                 datetime.
`char[]'               `MYSQL_TYPE_STRING'       *Note `TEXT': blob,
                                                 *Note `CHAR': char,
                                                 *Note `VARCHAR': char.
`char[]'               `MYSQL_TYPE_BLOB'         *Note `BLOB': blob,
                                                 *Note `BINARY':
                                                 binary-varbinary, *Note
                                                 `VARBINARY':
                                                 binary-varbinary.
                       `MYSQL_TYPE_NULL'         `NULL'

Use `MYSQL_TYPE_NULL' as indicated in the description for the `is_null'
member in *Note c-api-prepared-statement-data-structures::.

For input string data, use `MYSQL_TYPE_STRING' or `MYSQL_TYPE_BLOB'
depending on whether the value is a character (nonbinary) or binary
string:

   * `MYSQL_TYPE_STRING' indicates character input string data. The
     value is assumed to be in the character set indicated by the
     `character_set_client' system variable. If the server stores the
     value into a column with a different character set, it converts
     the value to that character set.

   * `MYSQL_TYPE_BLOB' indicates binary input string data. The value is
     treated as having the `binary' character set. That is, it is
     treated as a byte string and no conversion occurs.

The following table shows the permissible values for the `buffer_type'
member of `MYSQL_BIND' structures for output values received from the
server. The table shows the SQL types of received values, the
corresponding type codes that such values have in result set metadata,
and the recommended C language data types to bind to the `MYSQL_BIND'
structure to receive the SQL values without conversion. Choose the
`buffer_type' value according to the data type of the C language
variable that you are binding. For the integer types, you should also
set the `is_unsigned' member to indicate whether the variable is signed
or unsigned.

SQL Type of Received   `buffer_type' Value       Output Variable C Type
Value                                            
*Note `TINYINT':       `MYSQL_TYPE_TINY'         `signed char'
numeric-types.                                   
*Note `SMALLINT':      `MYSQL_TYPE_SHORT'        `short int'
numeric-types.                                   
*Note `MEDIUMINT':     `MYSQL_TYPE_INT24'        `int'
numeric-types.                                   
*Note `INT':           `MYSQL_TYPE_LONG'         `int'
numeric-types.                                   
*Note `BIGINT':        `MYSQL_TYPE_LONGLONG'     `long long int'
numeric-types.                                   
*Note `FLOAT':         `MYSQL_TYPE_FLOAT'        `float'
numeric-types.                                   
*Note `DOUBLE':        `MYSQL_TYPE_DOUBLE'       `double'
numeric-types.                                   
*Note `DECIMAL':       `MYSQL_TYPE_NEWDECIMAL'   `char[]'
numeric-types.                                   
*Note `YEAR': year.    `MYSQL_TYPE_SHORT'        `short int'
*Note `TIME': time.    `MYSQL_TYPE_TIME'         `MYSQL_TIME'
*Note `DATE':          `MYSQL_TYPE_DATE'         `MYSQL_TIME'
datetime.                                        
*Note `DATETIME':      `MYSQL_TYPE_DATETIME'     `MYSQL_TIME'
datetime.                                        
*Note `TIMESTAMP':     `MYSQL_TYPE_TIMESTAMP'    `MYSQL_TIME'
datetime.                                        
*Note `CHAR': char,    `MYSQL_TYPE_STRING'       `char[]'
*Note `BINARY':                                  
binary-varbinary.                                
*Note `VARCHAR': char, `MYSQL_TYPE_VAR_STRING'   `char[]'
*Note `VARBINARY':                               
binary-varbinary.                                
*Note `TINYBLOB':      `MYSQL_TYPE_TINY_BLOB'    `char[]'
blob, *Note                                      
`TINYTEXT': blob.                                
*Note `BLOB': blob,    `MYSQL_TYPE_BLOB'         `char[]'
*Note `TEXT': blob.                              
*Note `MEDIUMBLOB':    `MYSQL_TYPE_MEDIUM_BLOB'  `char[]'
blob, *Note                                      
`MEDIUMTEXT': blob.                              
*Note `LONGBLOB':      `MYSQL_TYPE_LONG_BLOB'    `char[]'
blob, *Note                                      
`LONGTEXT': blob.                                
*Note `BIT':           `MYSQL_TYPE_BIT'          `char[]'
numeric-types.                                   


File: manual.info,  Node: c-api-prepared-statement-type-conversions,  Prev: c-api-prepared-statement-type-codes,  Up: c-api-prepared-statement-data-structures

20.8.5.2 C API Prepared Statement Type Conversions
..................................................

Prepared statements transmit data between the client and server using C
language variables on the client side that correspond to SQL values on
the server side. If there is a mismatch between the C variable type on
the client side and the corresponding SQL value type on the server
side, MySQL performs implicit type conversions in both directions.

MySQL knows the type code for the SQL value on the server side.  The
`buffer_type' value in the `MYSQL_BIND' structure indicates the type
code of the C variable that holds the value on the client side. The two
codes together tell MySQL what conversion must be performed, if any.
Here are some examples:

   * If you use `MYSQL_TYPE_LONG' with an `int' variable to pass an
     integer value to the server that is to be stored into a *Note
     `FLOAT': numeric-types. column, MySQL converts the value to
     floating-point format before storing it.

   * If you fetch an SQL *Note `MEDIUMINT': numeric-types.  column
     value, but specify a `buffer_type' value of `MYSQL_TYPE_LONGLONG'
     and use a C variable of type `long long int' as the destination
     buffer, MySQL converts the *Note `MEDIUMINT': numeric-types. value
     (which requires less than 8 bytes) for storage into the `long long
     int' (an 8-byte variable).

   * If you fetch a numeric column with a value of 255 into a `char[4]'
     character array and specify a `buffer_type' value of
     `MYSQL_TYPE_STRING', the resulting value in the array is a 4-byte
     string `'255\0''.

   * MySQL returns *Note `DECIMAL': numeric-types. values as the string
     representation of the original server-side value, which is why the
     corresponding C type is `char[]'. For example, `12.345' is
     returned to the client as `'12.345''. If you specify
     `MYSQL_TYPE_NEWDECIMAL' and bind a string buffer to the
     `MYSQL_BIND' structure, *Note `mysql_stmt_fetch()':
     mysql-stmt-fetch. stores the value in the buffer as a string
     without conversion. If instead you specify a numeric variable and
     type code, *Note `mysql_stmt_fetch()': mysql-stmt-fetch. converts
     the string-format *Note `DECIMAL': numeric-types.  value to
     numeric form.

   * For the `MYSQL_TYPE_BIT' type code, *Note `BIT': numeric-types.
     values are returned into a string buffer, which is why the
     corresponding C type is `char[]'. The value represents a bit string
     that requires interpretation on the client side. To return the
     value as a type that is easier to deal with, you can cause the
     value to be cast to integer using either of the following types of
     expressions:

          SELECT bit_col + 0 FROM t
          SELECT CAST(bit_col AS UNSIGNED) FROM t

     To retrieve the value, bind an integer variable large enough to
     hold the value and specify the appropriate corresponding integer
     type code.

Before binding variables to the `MYSQL_BIND' structures that are to be
used for fetching column values, you can check the type codes for each
column of the result set. This might be desirable if you want to
determine which variable types would be best to use to avoid type
conversions. To get the type codes, call *Note
`mysql_stmt_result_metadata()': mysql-stmt-result-metadata.  after
executing the prepared statement with *Note `mysql_stmt_execute()':
mysql-stmt-execute. The metadata provides access to the type codes for
the result set as described in *Note mysql-stmt-result-metadata::, and
*Note c-api-data-structures::.

To determine whether output string values in a result set returned from
the server contain binary or nonbinary data, check whether the
`charsetnr' value of the result set metadata is 63 (see *Note
c-api-data-structures::). If so, the character set is `binary', which
indicates binary rather than nonbinary data. This enables you to
distinguish *Note `BINARY': binary-varbinary. from *Note `CHAR': char,
*Note `VARBINARY': binary-varbinary. from *Note `VARCHAR': char, and the
*Note `BLOB': blob. types from the *Note `TEXT': blob. types.

If you cause the `max_length' member of the `MYSQL_FIELD' column
metadata structures to be set (by calling *Note
`mysql_stmt_attr_set()': mysql-stmt-attr-set.), be aware that the
`max_length' values for the result set indicate the lengths of the
longest string representation of the result values, not the lengths of
the binary representation.  That is, `max_length' does not necessarily
correspond to the size of the buffers needed to fetch the values with
the binary protocol used for prepared statements. Choose the size of
the buffers according to the types of the variables into which you
fetch the values. For example, a `TINYINT' column containing the value
-128 might have a `max_length' value of 4. But the binary
representation of any `TINYINT' value requires only 1 byte for storage,
so you can supply a `signed char' variable in which to store the value
and set `is_unsigned' to indicate that values are signed.


File: manual.info,  Node: c-api-prepared-statement-function-overview,  Next: c-api-prepared-statement-functions,  Prev: c-api-prepared-statement-data-structures,  Up: c

20.8.6 C API Prepared Statement Function Overview
-------------------------------------------------

The functions available for prepared statement processing are
summarized here and described in greater detail in a later section. See
*Note c-api-prepared-statement-functions::.

Function                Description
*Note                   Returns the number of rows changed, deleted, or
`mysql_stmt_affected_rows()':inserted by prepared *Note `UPDATE': update,
mysql-stmt-affected-rows.*Note `DELETE': delete, or *Note `INSERT':
                        insert. statement
*Note                   Gets value of an attribute for a prepared
`mysql_stmt_attr_get()':statement
mysql-stmt-attr-get.    
*Note                   Sets an attribute for a prepared statement
`mysql_stmt_attr_set()':
mysql-stmt-attr-set.    
*Note                   Associates application data buffers with the
`mysql_stmt_bind_param()':parameter markers in a prepared SQL statement
mysql-stmt-bind-param.  
*Note                   Associates application data buffers with columns
`mysql_stmt_bind_result()':in a result set
mysql-stmt-bind-result. 
*Note                   Frees memory used by a prepared statement
`mysql_stmt_close()':   
mysql-stmt-close.       
*Note                   Seeks to an arbitrary row number in a statement
`mysql_stmt_data_seek()':result set
mysql-stmt-data-seek.   
*Note                   Returns the error number for the last statement
`mysql_stmt_errno()':   execution
mysql-stmt-errno.       
*Note                   Returns the error message for the last statement
`mysql_stmt_error()':   execution
mysql-stmt-error.       
*Note                   Executes a prepared statement
`mysql_stmt_execute()': 
mysql-stmt-execute.     
*Note                   Fetches the next row of data from a result set
`mysql_stmt_fetch()':   and returns data for all bound columns
mysql-stmt-fetch.       
*Note                   Fetch data for one column of the current row of
`mysql_stmt_fetch_column()':a result set
mysql-stmt-fetch-column.
*Note                   Returns the number of result columns for the
`mysql_stmt_field_count()':most recent statement
mysql-stmt-field-count. 
*Note                   Free the resources allocated to a statement
`mysql_stmt_free_result()':handle
mysql-stmt-free-result. 
*Note                   Allocates memory for a `MYSQL_STMT' structure and
`mysql_stmt_init()':    initializes it
mysql-stmt-init.        
*Note                   Returns the ID generated for an `AUTO_INCREMENT'
`mysql_stmt_insert_id()':column by a prepared statement
mysql-stmt-insert-id.   
*Note                   Returns the row count from a buffered statement
`mysql_stmt_num_rows()':result set
mysql-stmt-num-rows.    
*Note                   Returns the number of parameters in a prepared
`mysql_stmt_param_count()':statement
mysql-stmt-param-count. 
*Note                   (Return parameter metadata in the form of a
`mysql_stmt_param_metadata()':result set) Currently, this function does nothing
mysql-stmt-param-metadata.
*Note                   Prepares an SQL statement string for execution
`mysql_stmt_prepare()': 
mysql-stmt-prepare.     
*Note                   Resets the statement buffers in the server
`mysql_stmt_reset()':   
mysql-stmt-reset.       
*Note                   Returns prepared statement metadata in the form
`mysql_stmt_result_metadata()':of a result set
mysql-stmt-result-metadata.
*Note                   Seeks to a row offset in a statement result set,
`mysql_stmt_row_seek()':using value returned from *Note
mysql-stmt-row-seek.    `mysql_stmt_row_tell()': mysql-stmt-row-tell.
*Note                   Returns the statement row cursor position
`mysql_stmt_row_tell()':
mysql-stmt-row-tell.    
*Note                   Sends long data in chunks to server
`mysql_stmt_send_long_data()':
mysql-stmt-send-long-data.
*Note                   Returns the SQLSTATE error code for the last
`mysql_stmt_sqlstate()':statement execution
mysql-stmt-sqlstate.    
*Note                   Retrieves a complete result set to the client
`mysql_stmt_store_result()':
mysql-stmt-store-result.

Call *Note `mysql_stmt_init()': mysql-stmt-init. to create a statement
handle, then *Note `mysql_stmt_prepare()': mysql-stmt-prepare. to
prepare the statement string, *Note `mysql_stmt_bind_param()':
mysql-stmt-bind-param. to supply the parameter data, and *Note
`mysql_stmt_execute()': mysql-stmt-execute. to execute the statement.
You can repeat the *Note `mysql_stmt_execute()': mysql-stmt-execute. by
changing parameter values in the respective buffers supplied through
*Note `mysql_stmt_bind_param()': mysql-stmt-bind-param.

You can send text or binary data in chunks to server using *Note
`mysql_stmt_send_long_data()': mysql-stmt-send-long-data. See *Note
mysql-stmt-send-long-data::.

If the statement is a *Note `SELECT': select. or any other statement
that produces a result set, *Note `mysql_stmt_prepare()':
mysql-stmt-prepare. also returns the result set metadata information in
the form of a `MYSQL_RES' result set through *Note
`mysql_stmt_result_metadata()': mysql-stmt-result-metadata.

You can supply the result buffers using *Note
`mysql_stmt_bind_result()': mysql-stmt-bind-result, so that the *Note
`mysql_stmt_fetch()': mysql-stmt-fetch.  automatically returns data to
these buffers. This is row-by-row fetching.

When statement execution has been completed, close the statement handle
using *Note `mysql_stmt_close()': mysql-stmt-close. so that all
resources associated with it can be freed.

If you obtained a *Note `SELECT': select.  statement's result set
metadata by calling *Note `mysql_stmt_result_metadata()':
mysql-stmt-result-metadata, you should also free the metadata using
*Note `mysql_free_result()': mysql-free-result.

* Execution Steps *

To prepare and execute a statement, an application follows these steps:

  1. Create a prepared statement handle with *Note `mysql_stmt_init()':
     mysql-stmt-init. To prepare the statement on the server, call
     *Note `mysql_stmt_prepare()': mysql-stmt-prepare. and pass it a
     string containing the SQL statement.

  2. If the statement will produce a result set, call *Note
     `mysql_stmt_result_metadata()': mysql-stmt-result-metadata.  to
     obtain the result set metadata. This metadata is itself in the
     form of result set, albeit a separate one from the one that
     contains the rows returned by the query. The metadata result set
     indicates how many columns are in the result and contains
     information about each column.

  3. Set the values of any parameters using *Note
     `mysql_stmt_bind_param()': mysql-stmt-bind-param. All parameters
     must be set. Otherwise, statement execution returns an error or
     produces unexpected results.

  4. Call *Note `mysql_stmt_execute()': mysql-stmt-execute. to execute
     the statement.

  5. If the statement produces a result set, bind the data buffers to
     use for retrieving the row values by calling *Note
     `mysql_stmt_bind_result()': mysql-stmt-bind-result.

  6. Fetch the data into the buffers row by row by calling *Note
     `mysql_stmt_fetch()': mysql-stmt-fetch. repeatedly until no more
     rows are found.

  7. Repeat steps 3 through 6 as necessary, by changing the parameter
     values and re-executing the statement.

When *Note `mysql_stmt_prepare()': mysql-stmt-prepare. is called, the
MySQL client/server protocol performs these actions:

   * The server parses the statement and sends the okay status back to
     the client by assigning a statement ID. It also sends total number
     of parameters, a column count, and its metadata if it is a result
     set oriented statement. All syntax and semantics of the statement
     are checked by the server during this call.

   * The client uses this statement ID for the further operations, so
     that the server can identify the statement from among its pool of
     statements.

When *Note `mysql_stmt_execute()': mysql-stmt-execute. is called, the
MySQL client/server protocol performs these actions:

   * The client uses the statement handle and sends the parameter data
     to the server.

   * The server identifies the statement using the ID provided by the
     client, replaces the parameter markers with the newly supplied
     data, and executes the statement. If the statement produces a
     result set, the server sends the data back to the client.
     Otherwise, it sends an okay status and the number of rows changed,
     deleted, or inserted.

When *Note `mysql_stmt_fetch()': mysql-stmt-fetch. is called, the MySQL
client/server protocol performs these actions:

   * The client reads the data from the current row of the result set
     and places it into the application data buffers by doing the
     necessary conversions. If the application buffer type is same as
     that of the field type returned from the server, the conversions
     are straightforward.

If an error occurs, you can get the statement error number, error
message, and SQLSTATE code using *Note `mysql_stmt_errno()':
mysql-stmt-errno, *Note `mysql_stmt_error()': mysql-stmt-error, and
*Note `mysql_stmt_sqlstate()': mysql-stmt-sqlstate, respectively.

* Prepared Statement Logging *

For prepared statements that are executed with the *Note
`mysql_stmt_prepare()': mysql-stmt-prepare. and *Note
`mysql_stmt_execute()': mysql-stmt-execute. C API functions, the server
writes `Prepare' and `Execute' lines to the general query log so that
you can tell when statements are prepared and executed.

Suppose that you prepare and execute a statement as follows:

  1. Call *Note `mysql_stmt_prepare()': mysql-stmt-prepare. to prepare
     the statement string `"SELECT ?"'.

  2. Call *Note `mysql_stmt_bind_param()': mysql-stmt-bind-param.  to
     bind the value `3' to the parameter in the prepared statement.

  3. Call *Note `mysql_stmt_execute()': mysql-stmt-execute. to execute
     the prepared statement.

As a result of the preceding calls, the server writes the following
lines to the general query log:

     Prepare  [1] SELECT ?
     Execute  [1] SELECT 3

Each `Prepare' and `Execute' line in the log is tagged with a `[N]'
statement identifier so that you can keep track of which prepared
statement is being logged. N is a positive integer. If there are
multiple prepared statements active simultaneously for the client, N
may be greater than 1. Each `Execute' lines shows a prepared statement
after substitution of data values for `?' parameters.


File: manual.info,  Node: c-api-prepared-statement-functions,  Next: c-api-thread-functions,  Prev: c-api-prepared-statement-function-overview,  Up: c

20.8.7 C API Prepared Statement Function Descriptions
-----------------------------------------------------

* Menu:

* mysql-stmt-affected-rows::     `mysql_stmt_affected_rows()'
* mysql-stmt-attr-get::          `mysql_stmt_attr_get()'
* mysql-stmt-attr-set::          `mysql_stmt_attr_set()'
* mysql-stmt-bind-param::        `mysql_stmt_bind_param()'
* mysql-stmt-bind-result::       `mysql_stmt_bind_result()'
* mysql-stmt-close::             `mysql_stmt_close()'
* mysql-stmt-data-seek::         `mysql_stmt_data_seek()'
* mysql-stmt-errno::             `mysql_stmt_errno()'
* mysql-stmt-error::             `mysql_stmt_error()'
* mysql-stmt-execute::           `mysql_stmt_execute()'
* mysql-stmt-fetch::             `mysql_stmt_fetch()'
* mysql-stmt-fetch-column::      `mysql_stmt_fetch_column()'
* mysql-stmt-field-count::       `mysql_stmt_field_count()'
* mysql-stmt-free-result::       `mysql_stmt_free_result()'
* mysql-stmt-init::              `mysql_stmt_init()'
* mysql-stmt-insert-id::         `mysql_stmt_insert_id()'
* mysql-stmt-num-rows::          `mysql_stmt_num_rows()'
* mysql-stmt-param-count::       `mysql_stmt_param_count()'
* mysql-stmt-param-metadata::    `mysql_stmt_param_metadata()'
* mysql-stmt-prepare::           `mysql_stmt_prepare()'
* mysql-stmt-reset::             `mysql_stmt_reset()'
* mysql-stmt-result-metadata::   `mysql_stmt_result_metadata()'
* mysql-stmt-row-seek::          `mysql_stmt_row_seek()'
* mysql-stmt-row-tell::          `mysql_stmt_row_tell()'
* mysql-stmt-send-long-data::    `mysql_stmt_send_long_data()'
* mysql-stmt-sqlstate::          `mysql_stmt_sqlstate()'
* mysql-stmt-store-result::      `mysql_stmt_store_result()'

To prepare and execute queries, use the functions described in detail
in the following sections.

All functions that operate with a `MYSQL_STMT' structure begin with the
prefix `mysql_stmt_'.

To create a `MYSQL_STMT' handle, use the *Note `mysql_stmt_init()':
mysql-stmt-init. function.


File: manual.info,  Node: mysql-stmt-affected-rows,  Next: mysql-stmt-attr-get,  Prev: c-api-prepared-statement-functions,  Up: c-api-prepared-statement-functions

20.8.7.1 `mysql_stmt_affected_rows()'
.....................................

`my_ulonglong mysql_stmt_affected_rows(MYSQL_STMT *stmt)'

* Description *

*Note `mysql_stmt_affected_rows()': mysql-stmt-affected-rows. may be
called immediately after executing a statement with *Note
`mysql_stmt_execute()': mysql-stmt-execute. It is like *Note
`mysql_affected_rows()': mysql-affected-rows. but for prepared
statements. For a description of what the affected-rows value returned
by this function means, See *Note mysql-affected-rows::.

* Errors *

None.

* Example *

See the Example in *Note mysql-stmt-execute::.


File: manual.info,  Node: mysql-stmt-attr-get,  Next: mysql-stmt-attr-set,  Prev: mysql-stmt-affected-rows,  Up: c-api-prepared-statement-functions

20.8.7.2 `mysql_stmt_attr_get()'
................................

`my_bool mysql_stmt_attr_get(MYSQL_STMT *stmt, enum enum_stmt_attr_type
option, void *arg)'

* Description *

Can be used to get the current value for a statement attribute.

The `option' argument is the option that you want to get; the `arg'
should point to a variable that should contain the option value. If the
option is an integer, `arg' should point to the value of the integer.

See *Note mysql-stmt-attr-set::, for a list of options and option types.

*Note*:

In MySQL 5.0, *Note `mysql_stmt_attr_get()': mysql-stmt-attr-get. uses
`unsigned int *', not `my_bool *', for `STMT_ATTR_UPDATE_MAX_LENGTH'.
This was corrected in MySQL 5.1.7.

* Return Values *

Zero if successful. Nonzero if `option' is unknown.

* Errors *

None.


File: manual.info,  Node: mysql-stmt-attr-set,  Next: mysql-stmt-bind-param,  Prev: mysql-stmt-attr-get,  Up: c-api-prepared-statement-functions

20.8.7.3 `mysql_stmt_attr_set()'
................................

`my_bool mysql_stmt_attr_set(MYSQL_STMT *stmt, enum enum_stmt_attr_type
option, const void *arg)'

* Description *

Can be used to affect behavior for a prepared statement. This function
may be called multiple times to set several options.

The `option' argument is the option that you want to set. The `arg'
argument is the value for the option. `arg' should point to a variable
that is set to the desired attribute value. The variable type is as
indicated in the following table.

The following table shows the possible `option' values.

Option                         Argument Type  Function
`STMT_ATTR_UPDATE_MAX_LENGTH'  `my_bool *'    If set to 1, causes *Note
                                              `mysql_stmt_store_result()':
                                              mysql-stmt-store-result.
                                              to update the metadata
                                              `MYSQL_FIELD->max_length'
                                              value.
`STMT_ATTR_CURSOR_TYPE'        `unsigned      Type of cursor to open for
                               long *'        statement when *Note
                                              `mysql_stmt_execute()':
                                              mysql-stmt-execute. is
                                              invoked. `*arg' can be
                                              `CURSOR_TYPE_NO_CURSOR'
                                              (the default) or
                                              `CURSOR_TYPE_READ_ONLY'.
`STMT_ATTR_PREFETCH_ROWS'      `unsigned      Number of rows to fetch
                               long *'        from server at a time when
                                              using a cursor.  `*arg'
                                              can be in the range from 1
                                              to the maximum value of
                                              `unsigned long'.  The
                                              default is 1.

*Note*:

In MySQL 5.0, *Note `mysql_stmt_attr_get()': mysql-stmt-attr-get. uses
`unsigned int *', not `my_bool *', for `STMT_ATTR_UPDATE_MAX_LENGTH'.
This is corrected in MySQL 5.1.7.

If you use the `STMT_ATTR_CURSOR_TYPE' option with
`CURSOR_TYPE_READ_ONLY', a cursor is opened for the statement when you
invoke *Note `mysql_stmt_execute()': mysql-stmt-execute. If there is
already an open cursor from a previous *Note `mysql_stmt_execute()':
mysql-stmt-execute. call, it closes the cursor before opening a new one.
*Note `mysql_stmt_reset()': mysql-stmt-reset. also closes any open
cursor before preparing the statement for re-execution.  *Note
`mysql_stmt_free_result()': mysql-stmt-free-result. closes any open
cursor.

If you open a cursor for a prepared statement, *Note
`mysql_stmt_store_result()': mysql-stmt-store-result. is unnecessary,
because that function causes the result set to be buffered on the
client side.

The `STMT_ATTR_CURSOR_TYPE' option was added in MySQL 5.0.2. The
`STMT_ATTR_PREFETCH_ROWS' option was added in MySQL 5.0.6.

* Return Values *

Zero if successful. Nonzero if `option' is unknown.

* Errors *

None.

* Example *

The following example opens a cursor for a prepared statement and sets
the number of rows to fetch at a time to 5:

     MYSQL_STMT *stmt;
     int rc;
     unsigned long type;
     unsigned long prefetch_rows = 5;

     stmt = mysql_stmt_init(mysql);
     type = (unsigned long) CURSOR_TYPE_READ_ONLY;
     rc = mysql_stmt_attr_set(stmt, STMT_ATTR_CURSOR_TYPE, (void*) &type);
     /* ... check return value ... */
     rc = mysql_stmt_attr_set(stmt, STMT_ATTR_PREFETCH_ROWS,
                              (void*) &prefetch_rows);
     /* ... check return value ... */


File: manual.info,  Node: mysql-stmt-bind-param,  Next: mysql-stmt-bind-result,  Prev: mysql-stmt-attr-set,  Up: c-api-prepared-statement-functions

20.8.7.4 `mysql_stmt_bind_param()'
..................................

`my_bool mysql_stmt_bind_param(MYSQL_STMT *stmt, MYSQL_BIND *bind)'

* Description *

*Note `mysql_stmt_bind_param()': mysql-stmt-bind-param. is used to bind
input data for the parameter markers in the SQL statement that was
passed to *Note `mysql_stmt_prepare()': mysql-stmt-prepare. It uses
`MYSQL_BIND' structures to supply the data.  `bind' is the address of
an array of `MYSQL_BIND' structures. The client library expects the
array to contain one element for each ``?'' parameter marker that is
present in the query.

Suppose that you prepare the following statement:

     INSERT INTO mytbl VALUES(?,?,?)

When you bind the parameters, the array of `MYSQL_BIND' structures must
contain three elements, and can be declared like this:

     MYSQL_BIND bind[3];

*Note c-api-prepared-statement-data-structures::, describes the members
of each `MYSQL_BIND' element and how they should be set to provide
input values.

* Return Values *

Zero if the bind operation was successful. Nonzero if an error occurred.

* Errors *

   * `CR_UNSUPPORTED_PARAM_TYPE'

     The conversion is not supported. Possibly the `buffer_type' value
     is illegal or is not one of the supported types.

   * `CR_OUT_OF_MEMORY'

     Out of memory.

   * `CR_UNKNOWN_ERROR'

     An unknown error occurred.

* Example *

See the Example in *Note mysql-stmt-execute::.


File: manual.info,  Node: mysql-stmt-bind-result,  Next: mysql-stmt-close,  Prev: mysql-stmt-bind-param,  Up: c-api-prepared-statement-functions

20.8.7.5 `mysql_stmt_bind_result()'
...................................

`my_bool mysql_stmt_bind_result(MYSQL_STMT *stmt, MYSQL_BIND *bind)'

* Description *

*Note `mysql_stmt_bind_result()': mysql-stmt-bind-result. is used to
associate (that is, bind) output columns in the result set to data
buffers and length buffers. When *Note `mysql_stmt_fetch()':
mysql-stmt-fetch. is called to fetch data, the MySQL client/server
protocol places the data for the bound columns into the specified
buffers.

All columns must be bound to buffers prior to calling *Note
`mysql_stmt_fetch()': mysql-stmt-fetch.  `bind' is the address of an
array of `MYSQL_BIND' structures. The client library expects the array
to contain one element for each column of the result set. If you do not
bind columns to `MYSQL_BIND' structures, *Note `mysql_stmt_fetch()':
mysql-stmt-fetch. simply ignores the data fetch. The buffers should be
large enough to hold the data values, because the protocol doesn't
return data values in chunks.

A column can be bound or rebound at any time, even after a result set
has been partially retrieved. The new binding takes effect the next time
*Note `mysql_stmt_fetch()': mysql-stmt-fetch. is called.  Suppose that
an application binds the columns in a result set and calls *Note
`mysql_stmt_fetch()': mysql-stmt-fetch.  The client/server protocol
returns data in the bound buffers.  Then suppose that the application
binds the columns to a different set of buffers. The protocol places
data into the newly bound buffers when the next call to *Note
`mysql_stmt_fetch()': mysql-stmt-fetch. occurs.

To bind a column, an application calls *Note
`mysql_stmt_bind_result()': mysql-stmt-bind-result. and passes the
type, address, and length of the output buffer into which the value
should be stored.  *Note c-api-prepared-statement-data-structures::,
describes the members of each `MYSQL_BIND' element and how they should
be set to receive output values.

* Return Values *

Zero if the bind operation was successful. Nonzero if an error occurred.

* Errors *

   * `CR_UNSUPPORTED_PARAM_TYPE'

     The conversion is not supported. Possibly the `buffer_type' value
     is illegal or is not one of the supported types.

   * `CR_OUT_OF_MEMORY'

     Out of memory.

   * `CR_UNKNOWN_ERROR'

     An unknown error occurred.

* Example *

See the Example in *Note mysql-stmt-fetch::.


File: manual.info,  Node: mysql-stmt-close,  Next: mysql-stmt-data-seek,  Prev: mysql-stmt-bind-result,  Up: c-api-prepared-statement-functions

20.8.7.6 `mysql_stmt_close()'
.............................

`my_bool mysql_stmt_close(MYSQL_STMT *)'

* Description *

Closes the prepared statement.  *Note `mysql_stmt_close()':
mysql-stmt-close. also deallocates the statement handle pointed to by
`stmt'.

If the current statement has pending or unread results, this function
cancels them so that the next query can be executed.

* Return Values *

Zero if the statement was freed successfully. Nonzero if an error
occurred.

* Errors *

   * `CR_SERVER_GONE_ERROR'

     The MySQL server has gone away.

   * `CR_UNKNOWN_ERROR'

     An unknown error occurred.

* Example *

See the Example in *Note mysql-stmt-execute::.


File: manual.info,  Node: mysql-stmt-data-seek,  Next: mysql-stmt-errno,  Prev: mysql-stmt-close,  Up: c-api-prepared-statement-functions

20.8.7.7 `mysql_stmt_data_seek()'
.................................

`void mysql_stmt_data_seek(MYSQL_STMT *stmt, my_ulonglong offset)'

* Description *

Seeks to an arbitrary row in a statement result set. The `offset' value
is a row number and should be in the range from `0' to *Note
`mysql_stmt_num_rows(stmt)-1': mysql-stmt-num-rows.

This function requires that the statement result set structure contains
the entire result of the last executed query, so *Note
`mysql_stmt_data_seek()': mysql-stmt-data-seek. may be used only in
conjunction with *Note `mysql_stmt_store_result()':
mysql-stmt-store-result.

* Return Values *

None.

* Errors *

None.


File: manual.info,  Node: mysql-stmt-errno,  Next: mysql-stmt-error,  Prev: mysql-stmt-data-seek,  Up: c-api-prepared-statement-functions

20.8.7.8 `mysql_stmt_errno()'
.............................

`unsigned int mysql_stmt_errno(MYSQL_STMT *stmt)'

* Description *

For the statement specified by `stmt', *Note `mysql_stmt_errno()':
mysql-stmt-errno. returns the error code for the most recently invoked
statement API function that can succeed or fail. A return value of zero
means that no error occurred. Client error message numbers are listed
in the MySQL `errmsg.h' header file. Server error message numbers are
listed in `mysqld_error.h'. Errors also are listed at *Note
error-handling::.

* Return Values *

An error code value. Zero if no error occurred.

* Errors *

None.


File: manual.info,  Node: mysql-stmt-error,  Next: mysql-stmt-execute,  Prev: mysql-stmt-errno,  Up: c-api-prepared-statement-functions

20.8.7.9 `mysql_stmt_error()'
.............................

`const char *mysql_stmt_error(MYSQL_STMT *stmt)'

* Description *

For the statement specified by `stmt', *Note `mysql_stmt_error()':
mysql-stmt-error. returns a null-terminated string containing the error
message for the most recently invoked statement API function that can
succeed or fail. An empty string (`""') is returned if no error
occurred. This means the following two tests are equivalent:

     if(*mysql_stmt_errno(stmt))
     {
       // an error occurred
     }

     if (mysql_stmt_error(stmt)[0])
     {
       // an error occurred
     }

The language of the client error messages may be changed by recompiling
the MySQL client library. Currently, you can choose error messages in
several different languages.

* Return Values *

A character string that describes the error. An empty string if no
error occurred.

* Errors *

None.


File: manual.info,  Node: mysql-stmt-execute,  Next: mysql-stmt-fetch,  Prev: mysql-stmt-error,  Up: c-api-prepared-statement-functions

20.8.7.10 `mysql_stmt_execute()'
................................

`int mysql_stmt_execute(MYSQL_STMT *stmt)'

* Description *

*Note `mysql_stmt_execute()': mysql-stmt-execute. executes the prepared
query associated with the statement handle. The currently bound
parameter marker values are sent to server during this call, and the
server replaces the markers with this newly supplied data.

Statement processing following *Note `mysql_stmt_execute()':
mysql-stmt-execute. depends on the type of statement:

   * For an *Note `UPDATE': update, *Note `DELETE': delete, or *Note
     `INSERT': insert, the number of changed, deleted, or inserted rows
     can be found by calling *Note `mysql_stmt_affected_rows()':
     mysql-stmt-affected-rows.

   * For a statement such as *Note `SELECT': select. that generates a
     result set, you must call *Note `mysql_stmt_fetch()':
     mysql-stmt-fetch. to fetch the data prior to calling any other
     functions that result in query processing. For more information on
     how to fetch the results, refer to *Note mysql-stmt-fetch::.

     Do not following invocation of *Note `mysql_stmt_execute()':
     mysql-stmt-execute. with a call to *Note `mysql_store_result()':
     mysql-store-result.  or *Note `mysql_use_result()':
     mysql-use-result. Those functions are not intended for processing
     results from prepared statements.

For statements that generate a result set, you can request that *Note
`mysql_stmt_execute()': mysql-stmt-execute. open a cursor for the
statement by calling *Note `mysql_stmt_attr_set()':
mysql-stmt-attr-set. before executing the statement. If you execute a
statement multiple times, *Note `mysql_stmt_execute()':
mysql-stmt-execute.  closes any open cursor before opening a new one.

* Return Values *

Zero if execution was successful. Nonzero if an error occurred.

* Errors *

   * `CR_COMMANDS_OUT_OF_SYNC'

     Commands were executed in an improper order.

   * `CR_OUT_OF_MEMORY'

     Out of memory.

   * `CR_SERVER_GONE_ERROR'

     The MySQL server has gone away.

   * `CR_SERVER_LOST'

     The connection to the server was lost during the query.

   * `CR_UNKNOWN_ERROR'

     An unknown error occurred.

* Example *

The following example demonstrates how to create and populate a table
using *Note `mysql_stmt_init()': mysql-stmt-init, *Note
`mysql_stmt_prepare()': mysql-stmt-prepare, *Note
`mysql_stmt_param_count()': mysql-stmt-param-count, *Note
`mysql_stmt_bind_param()': mysql-stmt-bind-param, *Note
`mysql_stmt_execute()': mysql-stmt-execute, and *Note
`mysql_stmt_affected_rows()': mysql-stmt-affected-rows. The `mysql'
variable is assumed to be a valid connection handle. For an example
that shows how to retrieve data, see *Note mysql-stmt-fetch::.

     #define STRING_SIZE 50

     #define DROP_SAMPLE_TABLE "DROP TABLE IF EXISTS test_table"
     #define CREATE_SAMPLE_TABLE "CREATE TABLE test_table(col1 INT,\
                                                      col2 VARCHAR(40),\
                                                      col3 SMALLINT,\
                                                      col4 TIMESTAMP)"
     #define INSERT_SAMPLE "INSERT INTO \
                            test_table(col1,col2,col3) \
                            VALUES(?,?,?)"

     MYSQL_STMT    *stmt;
     MYSQL_BIND    bind[3];
     my_ulonglong  affected_rows;
     int           param_count;
     short         small_data;
     int           int_data;
     char          str_data[STRING_SIZE];
     unsigned long str_length;
     my_bool       is_null;

     if (mysql_query(mysql, DROP_SAMPLE_TABLE))
     {
       fprintf(stderr, " DROP TABLE failed\n");
       fprintf(stderr, " %s\n", mysql_error(mysql));
       exit(0);
     }

     if (mysql_query(mysql, CREATE_SAMPLE_TABLE))
     {
       fprintf(stderr, " CREATE TABLE failed\n");
       fprintf(stderr, " %s\n", mysql_error(mysql));
       exit(0);
     }

     /* Prepare an INSERT query with 3 parameters */
     /* (the TIMESTAMP column is not named; the server */
     /*  sets it to the current date and time) */
     stmt = mysql_stmt_init(mysql);
     if (!stmt)
     {
       fprintf(stderr, " mysql_stmt_init(), out of memory\n");
       exit(0);
     }
     if (mysql_stmt_prepare(stmt, INSERT_SAMPLE, strlen(INSERT_SAMPLE)))
     {
       fprintf(stderr, " mysql_stmt_prepare(), INSERT failed\n");
       fprintf(stderr, " %s\n", mysql_stmt_error(stmt));
       exit(0);
     }
     fprintf(stdout, " prepare, INSERT successful\n");

     /* Get the parameter count from the statement */
     param_count= mysql_stmt_param_count(stmt);
     fprintf(stdout, " total parameters in INSERT: %d\n", param_count);

     if (param_count != 3) /* validate parameter count */
     {
       fprintf(stderr, " invalid parameter count returned by MySQL\n");
       exit(0);
     }

     /* Bind the data for all 3 parameters */

     memset(bind, 0, sizeof(bind));

     /* INTEGER PARAM */
     /* This is a number type, so there is no need
        to specify buffer_length */
     bind[0].buffer_type= MYSQL_TYPE_LONG;
     bind[0].buffer= (char *)&int_data;
     bind[0].is_null= 0;
     bind[0].length= 0;

     /* STRING PARAM */
     bind[1].buffer_type= MYSQL_TYPE_STRING;
     bind[1].buffer= (char *)str_data;
     bind[1].buffer_length= STRING_SIZE;
     bind[1].is_null= 0;
     bind[1].length= &str_length;

     /* SMALLINT PARAM */
     bind[2].buffer_type= MYSQL_TYPE_SHORT;
     bind[2].buffer= (char *)&small_data;
     bind[2].is_null= &is_null;
     bind[2].length= 0;

     /* Bind the buffers */
     if (mysql_stmt_bind_param(stmt, bind))
     {
       fprintf(stderr, " mysql_stmt_bind_param() failed\n");
       fprintf(stderr, " %s\n", mysql_stmt_error(stmt));
       exit(0);
     }

     /* Specify the data values for the first row */
     int_data= 10;             /* integer */
     strncpy(str_data, "MySQL", STRING_SIZE); /* string  */
     str_length= strlen(str_data);

     /* INSERT SMALLINT data as NULL */
     is_null= 1;

     /* Execute the INSERT statement - 1*/
     if (mysql_stmt_execute(stmt))
     {
       fprintf(stderr, " mysql_stmt_execute(), 1 failed\n");
       fprintf(stderr, " %s\n", mysql_stmt_error(stmt));
       exit(0);
     }

     /* Get the number of affected rows */
     affected_rows= mysql_stmt_affected_rows(stmt);
     fprintf(stdout, " total affected rows(insert 1): %lu\n",
                     (unsigned long) affected_rows);

     if (affected_rows != 1) /* validate affected rows */
     {
       fprintf(stderr, " invalid affected rows by MySQL\n");
       exit(0);
     }

     /* Specify data values for second row,
        then re-execute the statement */
     int_data= 1000;
     strncpy(str_data, "
             The most popular Open Source database",
             STRING_SIZE);
     str_length= strlen(str_data);
     small_data= 1000;         /* smallint */
     is_null= 0;               /* reset */

     /* Execute the INSERT statement - 2*/
     if (mysql_stmt_execute(stmt))
     {
       fprintf(stderr, " mysql_stmt_execute, 2 failed\n");
       fprintf(stderr, " %s\n", mysql_stmt_error(stmt));
       exit(0);
     }

     /* Get the total rows affected */
     affected_rows= mysql_stmt_affected_rows(stmt);
     fprintf(stdout, " total affected rows(insert 2): %lu\n",
                     (unsigned long) affected_rows);

     if (affected_rows != 1) /* validate affected rows */
     {
       fprintf(stderr, " invalid affected rows by MySQL\n");
       exit(0);
     }

     /* Close the statement */
     if (mysql_stmt_close(stmt))
     {
       fprintf(stderr, " failed while closing the statement\n");
       fprintf(stderr, " %s\n", mysql_stmt_error(stmt));
       exit(0);
     }

*Note*:

For complete examples on the use of prepared statement functions, refer
to the file `tests/mysql_client_test.c'. This file can be obtained from
a MySQL source distribution or from the Bazaar source repository.


File: manual.info,  Node: mysql-stmt-fetch,  Next: mysql-stmt-fetch-column,  Prev: mysql-stmt-execute,  Up: c-api-prepared-statement-functions

20.8.7.11 `mysql_stmt_fetch()'
..............................

`int mysql_stmt_fetch(MYSQL_STMT *stmt)'

* Description *

*Note `mysql_stmt_fetch()': mysql-stmt-fetch. returns the next row in
the result set. It can be called only while the result set exists; that
is, after a call to *Note `mysql_stmt_execute()': mysql-stmt-execute.
for a statement such as *Note `SELECT': select. that produces a result
set.

*Note `mysql_stmt_fetch()': mysql-stmt-fetch. returns row data using
the buffers bound by *Note `mysql_stmt_bind_result()':
mysql-stmt-bind-result. It returns the data in those buffers for all
the columns in the current row set and the lengths are returned to the
`length' pointer. All columns must be bound by the application before
it calls *Note `mysql_stmt_fetch()': mysql-stmt-fetch.

By default, result sets are fetched unbuffered a row at a time from the
server. To buffer the entire result set on the client, call *Note
`mysql_stmt_store_result()': mysql-stmt-store-result.  after binding
the data buffers and before calling *Note `mysql_stmt_fetch()':
mysql-stmt-fetch.

If a fetched data value is a `NULL' value, the `*is_null' value of the
corresponding `MYSQL_BIND' structure contains TRUE (1).  Otherwise, the
data and its length are returned in the `*buffer' and `*length'
elements based on the buffer type specified by the application.  Each
numeric and temporal type has a fixed length, as listed in the
following table. The length of the string types depends on the length
of the actual data value, as indicated by `data_length'.

Type                                 Length
`MYSQL_TYPE_TINY'                    1
`MYSQL_TYPE_SHORT'                   2
`MYSQL_TYPE_LONG'                    4
`MYSQL_TYPE_LONGLONG'                8
`MYSQL_TYPE_FLOAT'                   4
`MYSQL_TYPE_DOUBLE'                  8
`MYSQL_TYPE_TIME'                    `sizeof(MYSQL_TIME)'
`MYSQL_TYPE_DATE'                    `sizeof(MYSQL_TIME)'
`MYSQL_TYPE_DATETIME'                `sizeof(MYSQL_TIME)'
`MYSQL_TYPE_STRING'                  `data length'
`MYSQL_TYPE_BLOB'                    `data_length'

In some cases you might want to determine the length of a column value
before fetching it with *Note `mysql_stmt_fetch()': mysql-stmt-fetch.
For example, the value might be a long string or *Note `BLOB': blob.
value for which you want to know how much space must be allocated. To
accomplish this, you can use these strategies:

   * Before invoking *Note `mysql_stmt_fetch()': mysql-stmt-fetch. to
     retrieve individual rows, pass `STMT_ATTR_UPDATE_MAX_LENGTH' to
     *Note `mysql_stmt_attr_set()': mysql-stmt-attr-set, then invoke
     *Note `mysql_stmt_store_result()': mysql-stmt-store-result. to
     buffer the entire result on the client side. Setting the
     `STMT_ATTR_UPDATE_MAX_LENGTH' attribute causes the maximal length
     of column values to be indicated by the `max_length' member of the
     result set metadata returned by *Note
     `mysql_stmt_result_metadata()': mysql-stmt-result-metadata.

   * Invoke *Note `mysql_stmt_fetch()': mysql-stmt-fetch.  with a
     zero-length buffer for the column in question and a pointer in
     which the real length can be stored. Then use the real length with
     *Note `mysql_stmt_fetch_column()': mysql-stmt-fetch-column.

          real_length= 0;

          bind[0].buffer= 0;
          bind[0].buffer_length= 0;
          bind[0].length= &real_length
          mysql_stmt_bind_result(stmt, bind);

          mysql_stmt_fetch(stmt);
          if (real_length > 0)
          {
            data= malloc(real_length);
            bind[0].buffer= data;
            bind[0].buffer_length= real_length;
            mysql_stmt_fetch_column(stmt, bind, 0, 0);
          }

* Return Values *

Return Value              Description
0                         Successful, the data has been fetched to
                          application data buffers.
1                         Error occurred. Error code and message can be
                          obtained by calling *Note
                          `mysql_stmt_errno()': mysql-stmt-errno. and
                          *Note `mysql_stmt_error()': mysql-stmt-error.
`MYSQL_NO_DATA'           No more rows/data exists
`MYSQL_DATA_TRUNCATED'    Data truncation occurred

`MYSQL_DATA_TRUNCATED' is returned when truncation reporting is
enabled. To determine which column values were truncated when this
value is returned, check the `error' members of the `MYSQL_BIND'
structures used for fetching values. Truncation reporting is enabled by
default, but can be controlled by calling *Note `mysql_options()':
mysql-options. with the `MYSQL_REPORT_DATA_TRUNCATION' option.

* Errors *

   * `CR_COMMANDS_OUT_OF_SYNC'

     Commands were executed in an improper order.

   * `CR_OUT_OF_MEMORY'

     Out of memory.

   * `CR_SERVER_GONE_ERROR'

     The MySQL server has gone away.

   * `CR_SERVER_LOST'

     The connection to the server was lost during the query.

   * `CR_UNKNOWN_ERROR'

     An unknown error occurred.

   * `CR_UNSUPPORTED_PARAM_TYPE'

     The buffer type is `MYSQL_TYPE_DATE', `MYSQL_TYPE_TIME',
     `MYSQL_TYPE_DATETIME', or `MYSQL_TYPE_TIMESTAMP', but the data type
     is not *Note `DATE': datetime, *Note `TIME': time, *Note
     `DATETIME': datetime, or *Note `TIMESTAMP': datetime.

   * All other unsupported conversion errors are returned from *Note
     `mysql_stmt_bind_result()': mysql-stmt-bind-result.

* Example *

The following example demonstrates how to fetch data from a table using
*Note `mysql_stmt_result_metadata()': mysql-stmt-result-metadata, *Note
`mysql_stmt_bind_result()': mysql-stmt-bind-result, and *Note
`mysql_stmt_fetch()': mysql-stmt-fetch. (This example expects to
retrieve the two rows inserted by the example shown in *Note
mysql-stmt-execute::.) The `mysql' variable is assumed to be a valid
connection handle.

     #define STRING_SIZE 50

     #define SELECT_SAMPLE "SELECT col1, col2, col3, col4 \
                            FROM test_table"

     MYSQL_STMT    *stmt;
     MYSQL_BIND    bind[4];
     MYSQL_RES     *prepare_meta_result;
     MYSQL_TIME    ts;
     unsigned long length[4];
     int           param_count, column_count, row_count;
     short         small_data;
     int           int_data;
     char          str_data[STRING_SIZE];
     my_bool       is_null[4];
     my_bool       error[4];

     /* Prepare a SELECT query to fetch data from test_table */
     stmt = mysql_stmt_init(mysql);
     if (!stmt)
     {
       fprintf(stderr, " mysql_stmt_init(), out of memory\n");
       exit(0);
     }
     if (mysql_stmt_prepare(stmt, SELECT_SAMPLE, strlen(SELECT_SAMPLE)))
     {
       fprintf(stderr, " mysql_stmt_prepare(), SELECT failed\n");
       fprintf(stderr, " %s\n", mysql_stmt_error(stmt));
       exit(0);
     }
     fprintf(stdout, " prepare, SELECT successful\n");

     /* Get the parameter count from the statement */
     param_count= mysql_stmt_param_count(stmt);
     fprintf(stdout, " total parameters in SELECT: %d\n", param_count);

     if (param_count != 0) /* validate parameter count */
     {
       fprintf(stderr, " invalid parameter count returned by MySQL\n");
       exit(0);
     }

     /* Fetch result set meta information */
     prepare_meta_result = mysql_stmt_result_metadata(stmt);
     if (!prepare_meta_result)
     {
       fprintf(stderr,
              " mysql_stmt_result_metadata(), \
                returned no meta information\n");
       fprintf(stderr, " %s\n", mysql_stmt_error(stmt));
       exit(0);
     }

     /* Get total columns in the query */
     column_count= mysql_num_fields(prepare_meta_result);
     fprintf(stdout,
             " total columns in SELECT statement: %d\n",
             column_count);

     if (column_count != 4) /* validate column count */
     {
       fprintf(stderr, " invalid column count returned by MySQL\n");
       exit(0);
     }

     /* Execute the SELECT query */
     if (mysql_stmt_execute(stmt))
     {
       fprintf(stderr, " mysql_stmt_execute(), failed\n");
       fprintf(stderr, " %s\n", mysql_stmt_error(stmt));
       exit(0);
     }

     /* Bind the result buffers for all 4 columns before fetching them */

     memset(bind, 0, sizeof(bind));

     /* INTEGER COLUMN */
     bind[0].buffer_type= MYSQL_TYPE_LONG;
     bind[0].buffer= (char *)&int_data;
     bind[0].is_null= &is_null[0];
     bind[0].length= &length[0];
     bind[0].error= &error[0];

     /* STRING COLUMN */
     bind[1].buffer_type= MYSQL_TYPE_STRING;
     bind[1].buffer= (char *)str_data;
     bind[1].buffer_length= STRING_SIZE;
     bind[1].is_null= &is_null[1];
     bind[1].length= &length[1];
     bind[1].error= &error[1];

     /* SMALLINT COLUMN */
     bind[2].buffer_type= MYSQL_TYPE_SHORT;
     bind[2].buffer= (char *)&small_data;
     bind[2].is_null= &is_null[2];
     bind[2].length= &length[2];
     bind[2].error= &error[2];

     /* TIMESTAMP COLUMN */
     bind[3].buffer_type= MYSQL_TYPE_TIMESTAMP;
     bind[3].buffer= (char *)&ts;
     bind[3].is_null= &is_null[3];
     bind[3].length= &length[3];
     bind[3].error= &error[3];

     /* Bind the result buffers */
     if (mysql_stmt_bind_result(stmt, bind))
     {
       fprintf(stderr, " mysql_stmt_bind_result() failed\n");
       fprintf(stderr, " %s\n", mysql_stmt_error(stmt));
       exit(0);
     }

     /* Now buffer all results to client (optional step) */
     if (mysql_stmt_store_result(stmt))
     {
       fprintf(stderr, " mysql_stmt_store_result() failed\n");
       fprintf(stderr, " %s\n", mysql_stmt_error(stmt));
       exit(0);
     }

     /* Fetch all rows */
     row_count= 0;
     fprintf(stdout, "Fetching results ...\n");
     while (!mysql_stmt_fetch(stmt))
     {
       row_count++;
       fprintf(stdout, "  row %d\n", row_count);

       /* column 1 */
       fprintf(stdout, "   column1 (integer)  : ");
       if (is_null[0])
         fprintf(stdout, " NULL\n");
       else
         fprintf(stdout, " %d(%ld)\n", int_data, length[0]);

       /* column 2 */
       fprintf(stdout, "   column2 (string)   : ");
       if (is_null[1])
         fprintf(stdout, " NULL\n");
       else
         fprintf(stdout, " %s(%ld)\n", str_data, length[1]);

       /* column 3 */
       fprintf(stdout, "   column3 (smallint) : ");
       if (is_null[2])
         fprintf(stdout, " NULL\n");
       else
         fprintf(stdout, " %d(%ld)\n", small_data, length[2]);

       /* column 4 */
       fprintf(stdout, "   column4 (timestamp): ");
       if (is_null[3])
         fprintf(stdout, " NULL\n");
       else
         fprintf(stdout, " %04d-%02d-%02d %02d:%02d:%02d (%ld)\n",
                          ts.year, ts.month, ts.day,
                          ts.hour, ts.minute, ts.second,
                          length[3]);
       fprintf(stdout, "\n");
     }

     /* Validate rows fetched */
     fprintf(stdout, " total rows fetched: %d\n", row_count);
     if (row_count != 2)
     {
       fprintf(stderr, " MySQL failed to return all rows\n");
       exit(0);
     }

     /* Free the prepared result metadata */
     mysql_free_result(prepare_meta_result);

     /* Close the statement */
     if (mysql_stmt_close(stmt))
     {
       fprintf(stderr, " failed while closing the statement\n");
       fprintf(stderr, " %s\n", mysql_stmt_error(stmt));
       exit(0);
     }


File: manual.info,  Node: mysql-stmt-fetch-column,  Next: mysql-stmt-field-count,  Prev: mysql-stmt-fetch,  Up: c-api-prepared-statement-functions

20.8.7.12 `mysql_stmt_fetch_column()'
.....................................

`int mysql_stmt_fetch_column(MYSQL_STMT *stmt, MYSQL_BIND *bind,
unsigned int column, unsigned long offset)'

* Description *

Fetch one column from the current result set row.  `bind' provides the
buffer where data should be placed. It should be set up the same way as
for *Note `mysql_stmt_bind_result()': mysql-stmt-bind-result.  `column'
indicates which column to fetch. The first column is numbered 0.
`offset' is the offset within the data value at which to begin
retrieving data.  This can be used for fetching the data value in
pieces. The beginning of the value is offset 0.

* Return Values *

Zero if the value was fetched successfully. Nonzero if an error
occurred.

* Errors *

   * `CR_INVALID_PARAMETER_NO'

     Invalid column number.

   * `CR_NO_DATA'

     The end of the result set has already been reached.


File: manual.info,  Node: mysql-stmt-field-count,  Next: mysql-stmt-free-result,  Prev: mysql-stmt-fetch-column,  Up: c-api-prepared-statement-functions

20.8.7.13 `mysql_stmt_field_count()'
....................................

`unsigned int mysql_stmt_field_count(MYSQL_STMT *stmt)'

* Description *

Returns the number of columns for the most recent statement for the
statement handler. This value is zero for statements such as *Note
`INSERT': insert. or *Note `DELETE': delete. that do not produce result
sets.

*Note `mysql_stmt_field_count()': mysql-stmt-field-count. can be called
after you have prepared a statement by invoking *Note
`mysql_stmt_prepare()': mysql-stmt-prepare.

* Return Values *

An unsigned integer representing the number of columns in a result set.

* Errors *

None.


File: manual.info,  Node: mysql-stmt-free-result,  Next: mysql-stmt-init,  Prev: mysql-stmt-field-count,  Up: c-api-prepared-statement-functions

20.8.7.14 `mysql_stmt_free_result()'
....................................

`my_bool mysql_stmt_free_result(MYSQL_STMT *stmt)'

* Description *

Releases memory associated with the result set produced by execution of
the prepared statement. If there is a cursor open for the statement,
*Note `mysql_stmt_free_result()': mysql-stmt-free-result. closes it.

* Return Values *

Zero if the result set was freed successfully. Nonzero if an error
occurred.

* Errors *


File: manual.info,  Node: mysql-stmt-init,  Next: mysql-stmt-insert-id,  Prev: mysql-stmt-free-result,  Up: c-api-prepared-statement-functions

20.8.7.15 `mysql_stmt_init()'
.............................

`MYSQL_STMT *mysql_stmt_init(MYSQL *mysql)'

* Description *

Create a `MYSQL_STMT' handle. The handle should be freed with *Note
`mysql_stmt_close(MYSQL_STMT *)': mysql-stmt-close.

See also *Note c-api-prepared-statement-data-structures::, for more
information.

* Return Values *

A pointer to a `MYSQL_STMT' structure in case of success. `NULL' if out
of memory.

* Errors *

   * `CR_OUT_OF_MEMORY'

     Out of memory.


File: manual.info,  Node: mysql-stmt-insert-id,  Next: mysql-stmt-num-rows,  Prev: mysql-stmt-init,  Up: c-api-prepared-statement-functions

20.8.7.16 `mysql_stmt_insert_id()'
..................................

`my_ulonglong mysql_stmt_insert_id(MYSQL_STMT *stmt)'

* Description *

Returns the value generated for an `AUTO_INCREMENT' column by the
prepared *Note `INSERT': insert. or *Note `UPDATE': update. statement.
Use this function after you have executed a prepared *Note `INSERT':
insert. statement on a table which contains an `AUTO_INCREMENT' field.

See *Note mysql-insert-id::, for more information.

* Return Values *

Value for `AUTO_INCREMENT' column which was automatically generated or
explicitly set during execution of prepared statement, or value
generated by `LAST_INSERT_ID(EXPR)' function. Return value is undefined
if statement does not set `AUTO_INCREMENT' value.

* Errors *

None.


File: manual.info,  Node: mysql-stmt-num-rows,  Next: mysql-stmt-param-count,  Prev: mysql-stmt-insert-id,  Up: c-api-prepared-statement-functions

20.8.7.17 `mysql_stmt_num_rows()'
.................................

`my_ulonglong mysql_stmt_num_rows(MYSQL_STMT *stmt)'

* Description *

Returns the number of rows in the result set.

The use of *Note `mysql_stmt_num_rows()': mysql-stmt-num-rows.  depends
on whether you used *Note `mysql_stmt_store_result()':
mysql-stmt-store-result. to buffer the entire result set in the
statement handle. If you use *Note `mysql_stmt_store_result()':
mysql-stmt-store-result, *Note `mysql_stmt_num_rows()':
mysql-stmt-num-rows. may be called immediately. Otherwise, the row
count is unavailable unless you count the rows as you fetch them.

*Note `mysql_stmt_num_rows()': mysql-stmt-num-rows. is intended for use
with statements that return a result set, such as *Note `SELECT':
select. For statements such as *Note `INSERT': insert, *Note `UPDATE':
update, or *Note `DELETE': delete, the number of affected rows can be
obtained with *Note `mysql_stmt_affected_rows()':
mysql-stmt-affected-rows.

* Return Values *

The number of rows in the result set.

* Errors *

None.


File: manual.info,  Node: mysql-stmt-param-count,  Next: mysql-stmt-param-metadata,  Prev: mysql-stmt-num-rows,  Up: c-api-prepared-statement-functions

20.8.7.18 `mysql_stmt_param_count()'
....................................

`unsigned long mysql_stmt_param_count(MYSQL_STMT *stmt)'

* Description *

Returns the number of parameter markers present in the prepared
statement.

* Return Values *

An unsigned long integer representing the number of parameters in a
statement.

* Errors *

None.

* Example *

See the Example in *Note mysql-stmt-execute::.


File: manual.info,  Node: mysql-stmt-param-metadata,  Next: mysql-stmt-prepare,  Prev: mysql-stmt-param-count,  Up: c-api-prepared-statement-functions

20.8.7.19 `mysql_stmt_param_metadata()'
.......................................

`MYSQL_RES *mysql_stmt_param_metadata(MYSQL_STMT *stmt)'

This function currently does nothing.

* Description *

* Return Values *

* Errors *


File: manual.info,  Node: mysql-stmt-prepare,  Next: mysql-stmt-reset,  Prev: mysql-stmt-param-metadata,  Up: c-api-prepared-statement-functions

20.8.7.20 `mysql_stmt_prepare()'
................................

`int mysql_stmt_prepare(MYSQL_STMT *stmt, const char *stmt_str,
unsigned long length)'

* Description *

Given the statement handle returned by *Note `mysql_stmt_init()':
mysql-stmt-init, prepares the SQL statement pointed to by the string
`stmt_str' and returns a status value. The string length should be
given by the `length' argument. The string must consist of a single SQL
statement. You should not add a terminating semicolon (``;'') or `\g'
to the statement.

The application can include one or more parameter markers in the SQL
statement by embedding question mark (``?'') characters into the SQL
string at the appropriate positions.

The markers are legal only in certain places in SQL statements.  For
example, they are permitted in the `VALUES()' list of an *Note
`INSERT': insert. statement (to specify column values for a row), or in
a comparison with a column in a `WHERE' clause to specify a comparison
value.  However, they are not permitted for identifiers (such as table
or column names), or to specify both operands of a binary operator such
as the `=' equal sign. The latter restriction is necessary because it
would be impossible to determine the parameter type. In general,
parameters are legal only in Data Manipulation Language (DML)
statements, and not in Data Definition Language (DDL) statements.

The parameter markers must be bound to application variables using
*Note `mysql_stmt_bind_param()': mysql-stmt-bind-param.  before
executing the statement.

* Return Values *

Zero if the statement was prepared successfully. Nonzero if an error
occurred.

* Errors *

   * `CR_COMMANDS_OUT_OF_SYNC'

     Commands were executed in an improper order.

   * `CR_OUT_OF_MEMORY'

     Out of memory.

   * `CR_SERVER_GONE_ERROR'

     The MySQL server has gone away.

   * `CR_SERVER_LOST'

     The connection to the server was lost during the query

   * `CR_UNKNOWN_ERROR'

     An unknown error occurred.

If the prepare operation was unsuccessful (that is, *Note
`mysql_stmt_prepare()': mysql-stmt-prepare. returns nonzero), the error
message can be obtained by calling *Note `mysql_stmt_error()':
mysql-stmt-error.

* Example *

See the Example in *Note mysql-stmt-execute::.


File: manual.info,  Node: mysql-stmt-reset,  Next: mysql-stmt-result-metadata,  Prev: mysql-stmt-prepare,  Up: c-api-prepared-statement-functions

20.8.7.21 `mysql_stmt_reset()'
..............................

`my_bool mysql_stmt_reset(MYSQL_STMT *stmt)'

* Description *

Resets a prepared statement on client and server to state after
prepare. It resets the statement on the server, data sent using *Note
`mysql_stmt_send_long_data()': mysql-stmt-send-long-data, unbuffered
result sets and current errors. It does not clear bindings or stored
result sets. Stored result sets will be cleared when executing the
prepared statement (or closing it).

To re-prepare the statement with another query, use *Note
`mysql_stmt_prepare()': mysql-stmt-prepare.

* Return Values *

Zero if the statement was reset successfully. Nonzero if an error
occurred.

* Errors *

   * `CR_COMMANDS_OUT_OF_SYNC'

     Commands were executed in an improper order.

   * `CR_SERVER_GONE_ERROR'

     The MySQL server has gone away.

   * `CR_SERVER_LOST'

     The connection to the server was lost during the query

   * `CR_UNKNOWN_ERROR'

     An unknown error occurred.


File: manual.info,  Node: mysql-stmt-result-metadata,  Next: mysql-stmt-row-seek,  Prev: mysql-stmt-reset,  Up: c-api-prepared-statement-functions

20.8.7.22 `mysql_stmt_result_metadata()'
........................................

`MYSQL_RES *mysql_stmt_result_metadata(MYSQL_STMT *stmt)'

* Description *

If a statement passed to *Note `mysql_stmt_prepare()':
mysql-stmt-prepare. is one that produces a result set, *Note
`mysql_stmt_result_metadata()': mysql-stmt-result-metadata.  returns
the result set metadata in the form of a pointer to a `MYSQL_RES'
structure that can be used to process the meta information such as
number of fields and individual field information. This result set
pointer can be passed as an argument to any of the field-based API
functions that process result set metadata, such as:

   * *Note `mysql_num_fields()': mysql-num-fields.

   * *Note `mysql_fetch_field()': mysql-fetch-field.

   * *Note `mysql_fetch_field_direct()': mysql-fetch-field-direct.

   * *Note `mysql_fetch_fields()': mysql-fetch-fields.

   * *Note `mysql_field_count()': mysql-field-count.

   * *Note `mysql_field_seek()': mysql-field-seek.

   * *Note `mysql_field_tell()': mysql-field-tell.

   * *Note `mysql_free_result()': mysql-free-result.

The result set structure should be freed when you are done with it,
which you can do by passing it to *Note `mysql_free_result()':
mysql-free-result. This is similar to the way you free a result set
obtained from a call to *Note `mysql_store_result()':
mysql-store-result.

The result set returned by *Note `mysql_stmt_result_metadata()':
mysql-stmt-result-metadata.  contains only metadata. It does not
contain any row results. The rows are obtained by using the statement
handle with *Note `mysql_stmt_fetch()': mysql-stmt-fetch.

* Return Values *

A `MYSQL_RES' result structure.  `NULL' if no meta information exists
for the prepared query.

* Errors *

   * `CR_OUT_OF_MEMORY'

     Out of memory.

   * `CR_UNKNOWN_ERROR'

     An unknown error occurred.

* Example *

See the Example in *Note mysql-stmt-fetch::.


File: manual.info,  Node: mysql-stmt-row-seek,  Next: mysql-stmt-row-tell,  Prev: mysql-stmt-result-metadata,  Up: c-api-prepared-statement-functions

20.8.7.23 `mysql_stmt_row_seek()'
.................................

`MYSQL_ROW_OFFSET mysql_stmt_row_seek(MYSQL_STMT *stmt,
MYSQL_ROW_OFFSET offset)'

* Description *

Sets the row cursor to an arbitrary row in a statement result set. The
`offset' value is a row offset that should be a value returned from
*Note `mysql_stmt_row_tell()': mysql-stmt-row-tell. or from *Note
`mysql_stmt_row_seek()': mysql-stmt-row-seek. This value is not a row
number; if you want to seek to a row within a result set by number, use
*Note `mysql_stmt_data_seek()': mysql-stmt-data-seek. instead.

This function requires that the result set structure contains the
entire result of the query, so *Note `mysql_stmt_row_seek()':
mysql-stmt-row-seek. may be used only in conjunction with *Note
`mysql_stmt_store_result()': mysql-stmt-store-result.

* Return Values *

The previous value of the row cursor. This value may be passed to a
subsequent call to *Note `mysql_stmt_row_seek()': mysql-stmt-row-seek.

* Errors *

None.


File: manual.info,  Node: mysql-stmt-row-tell,  Next: mysql-stmt-send-long-data,  Prev: mysql-stmt-row-seek,  Up: c-api-prepared-statement-functions

20.8.7.24 `mysql_stmt_row_tell()'
.................................

`MYSQL_ROW_OFFSET mysql_stmt_row_tell(MYSQL_STMT *stmt)'

* Description *

Returns the current position of the row cursor for the last *Note
`mysql_stmt_fetch()': mysql-stmt-fetch. This value can be used as an
argument to *Note `mysql_stmt_row_seek()': mysql-stmt-row-seek.

You should use *Note `mysql_stmt_row_tell()': mysql-stmt-row-tell. only
after *Note `mysql_stmt_store_result()': mysql-stmt-store-result.

* Return Values *

The current offset of the row cursor.

* Errors *

None.


File: manual.info,  Node: mysql-stmt-send-long-data,  Next: mysql-stmt-sqlstate,  Prev: mysql-stmt-row-tell,  Up: c-api-prepared-statement-functions

20.8.7.25 `mysql_stmt_send_long_data()'
.......................................

`my_bool mysql_stmt_send_long_data(MYSQL_STMT *stmt, unsigned int
parameter_number, const char *data, unsigned long length)'

* Description *

Enables an application to send parameter data to the server in pieces
(or `chunks'). Call this function after *Note
`mysql_stmt_bind_param()': mysql-stmt-bind-param. and before *Note
`mysql_stmt_execute()': mysql-stmt-execute. It can be called multiple
times to send the parts of a character or binary data value for a
column, which must be one of the *Note `TEXT': blob. or *Note `BLOB':
blob. data types.

`parameter_number' indicates which parameter to associate the data
with. Parameters are numbered beginning with 0. `data' is a pointer to
a buffer containing data to be sent, and `length' indicates the number
of bytes in the buffer.

*Note*:

The next *Note `mysql_stmt_execute()': mysql-stmt-execute.  call
ignores the bind buffer for all parameters that have been used with
*Note `mysql_stmt_send_long_data()': mysql-stmt-send-long-data.  since
last *Note `mysql_stmt_execute()': mysql-stmt-execute. or *Note
`mysql_stmt_reset()': mysql-stmt-reset.

If you want to reset/forget the sent data, you can do it with *Note
`mysql_stmt_reset()': mysql-stmt-reset. See *Note mysql-stmt-reset::.

* Return Values *

Zero if the data is sent successfully to server. Nonzero if an error
occurred.

* Errors *

   * `CR_INVALID_BUFFER_USE'

     The parameter does not have a string or binary type.

   * `CR_COMMANDS_OUT_OF_SYNC'

     Commands were executed in an improper order.

   * `CR_SERVER_GONE_ERROR'

     The MySQL server has gone away.

   * `CR_OUT_OF_MEMORY'

     Out of memory.

   * `CR_UNKNOWN_ERROR'

     An unknown error occurred.

* Example *

The following example demonstrates how to send the data for a *Note
`TEXT': blob. column in chunks. It inserts the data value `'MySQL - The
most popular Open Source database'' into the `text_column' column. The
`mysql' variable is assumed to be a valid connection handle.

     #define INSERT_QUERY "INSERT INTO \
                           test_long_data(text_column) VALUES(?)"

     MYSQL_BIND bind[1];
     long       length;

     stmt = mysql_stmt_init(mysql);
     if (!stmt)
     {
       fprintf(stderr, " mysql_stmt_init(), out of memory\n");
       exit(0);
     }
     if (mysql_stmt_prepare(stmt, INSERT_QUERY, strlen(INSERT_QUERY)))
     {
       fprintf(stderr, "\n mysql_stmt_prepare(), INSERT failed");
       fprintf(stderr, "\n %s", mysql_stmt_error(stmt));
       exit(0);
     }
      memset(bind, 0, sizeof(bind));
      bind[0].buffer_type= MYSQL_TYPE_STRING;
      bind[0].length= &length;
      bind[0].is_null= 0;

     /* Bind the buffers */
     if (mysql_stmt_bind_param(stmt, bind))
     {
       fprintf(stderr, "\n param bind failed");
       fprintf(stderr, "\n %s", mysql_stmt_error(stmt));
       exit(0);
     }

      /* Supply data in chunks to server */
      if (mysql_stmt_send_long_data(stmt,0,"MySQL",5))
     {
       fprintf(stderr, "\n send_long_data failed");
       fprintf(stderr, "\n %s", mysql_stmt_error(stmt));
       exit(0);
     }

      /* Supply the next piece of data */
      if (mysql_stmt_send_long_data(stmt,0,
                " - The most popular Open Source database",40))
     {
       fprintf(stderr, "\n send_long_data failed");
       fprintf(stderr, "\n %s", mysql_stmt_error(stmt));
       exit(0);
     }

      /* Now, execute the query */
      if (mysql_stmt_execute(stmt))
     {
       fprintf(stderr, "\n mysql_stmt_execute failed");
       fprintf(stderr, "\n %s", mysql_stmt_error(stmt));
       exit(0);
     }


File: manual.info,  Node: mysql-stmt-sqlstate,  Next: mysql-stmt-store-result,  Prev: mysql-stmt-send-long-data,  Up: c-api-prepared-statement-functions

20.8.7.26 `mysql_stmt_sqlstate()'
.................................

`const char *mysql_stmt_sqlstate(MYSQL_STMT *stmt)'

* Description *

For the statement specified by `stmt', *Note `mysql_stmt_sqlstate()':
mysql-stmt-sqlstate. returns a null-terminated string containing the
SQLSTATE error code for the most recently invoked prepared statement
API function that can succeed or fail. The error code consists of five
characters.  `"00000"' means `no error.' The values are specified by
ANSI SQL and ODBC. For a list of possible values, see *Note
error-handling::.

Note that not all MySQL errors are yet mapped to SQLSTATE codes.  The
value `"HY000"' (general error) is used for unmapped errors.

* Return Values *

A null-terminated character string containing the SQLSTATE error code.


File: manual.info,  Node: mysql-stmt-store-result,  Prev: mysql-stmt-sqlstate,  Up: c-api-prepared-statement-functions

20.8.7.27 `mysql_stmt_store_result()'
.....................................

`int mysql_stmt_store_result(MYSQL_STMT *stmt)'

* Description *

Result sets are produced by calling *Note `mysql_stmt_execute()':
mysql-stmt-execute. to executed prepared statements for SQL statements
such as *Note `SELECT': select, *Note `SHOW': show, *Note `DESCRIBE':
describe, and *Note `EXPLAIN': explain. By default, result sets for
successfully executed prepared statements are not buffered on the
client and *Note `mysql_stmt_fetch()': mysql-stmt-fetch. fetches them
one at a time from the server. To cause the complete result set to be
buffered on the client, call *Note `mysql_stmt_store_result()':
mysql-stmt-store-result. after binding data buffers with *Note
`mysql_stmt_bind_result()': mysql-stmt-bind-result. and before calling
*Note `mysql_stmt_fetch()': mysql-stmt-fetch. to fetch rows. (For an
example, see *Note mysql-stmt-fetch::.)

*Note `mysql_stmt_store_result()': mysql-stmt-store-result. is optional
for result set processing, unless you will call *Note
`mysql_stmt_data_seek()': mysql-stmt-data-seek, *Note
`mysql_stmt_row_seek()': mysql-stmt-row-seek, or *Note
`mysql_stmt_row_tell()': mysql-stmt-row-tell. Those functions require a
seekable result set.

It is unnecessary to call *Note `mysql_stmt_store_result()':
mysql-stmt-store-result. after executing an SQL statement that does not
produce a result set, but if you do, it does not harm or cause any
notable performance problem. You can detect whether the statement
produced a result set by checking if *Note
`mysql_stmt_result_metadata()': mysql-stmt-result-metadata.  returns
`NULL'. For more information, refer to *Note
mysql-stmt-result-metadata::.

*Note*:

MySQL doesn't by default calculate `MYSQL_FIELD->max_length' for all
columns in *Note `mysql_stmt_store_result()': mysql-stmt-store-result.
because calculating this would slow down *Note
`mysql_stmt_store_result()': mysql-stmt-store-result.  considerably and
most applications don't need `max_length'. If you want `max_length' to
be updated, you can call *Note `mysql_stmt_attr_set(MYSQL_STMT,
STMT_ATTR_UPDATE_MAX_LENGTH, &flag)': mysql-stmt-attr-set. to enable
this. See *Note mysql-stmt-attr-set::.

* Return Values *

Zero if the results are buffered successfully. Nonzero if an error
occurred.

* Errors *

   * `CR_COMMANDS_OUT_OF_SYNC'

     Commands were executed in an improper order.

   * `CR_OUT_OF_MEMORY'

     Out of memory.

   * `CR_SERVER_GONE_ERROR'

     The MySQL server has gone away.

   * `CR_SERVER_LOST'

     The connection to the server was lost during the query.

   * `CR_UNKNOWN_ERROR'

     An unknown error occurred.


File: manual.info,  Node: c-api-thread-functions,  Next: c-api-embedded-server-functions,  Prev: c-api-prepared-statement-functions,  Up: c

20.8.8 C API Threaded Function Descriptions
-------------------------------------------

* Menu:

* my-init::                      `my_init()'
* mysql-thread-end::             `mysql_thread_end()'
* mysql-thread-init::            `mysql_thread_init()'
* mysql-thread-safe::            `mysql_thread_safe()'

To create a threaded client, use the functions described in the
following sections. See also *Note threaded-clients::.


File: manual.info,  Node: my-init,  Next: mysql-thread-end,  Prev: c-api-thread-functions,  Up: c-api-thread-functions

20.8.8.1 `my_init()'
....................

`void my_init(void)'

* Description *

*Note `my_init()': my-init. initializes some global variables that
MySQL needs. If you are using a thread-safe client library, it also
calls *Note `mysql_thread_init()': mysql-thread-init. for this thread.

It is necessary for *Note `my_init()': my-init. to be called early in
the initialization phase of a program's use of the MySQL library.
However, *Note `my_init()': my-init. is automatically called by *Note
`mysql_init()': mysql-init, *Note `mysql_library_init()':
mysql-library-init, *Note `mysql_server_init()': mysql-server-init, and
*Note `mysql_connect()': mysql-connect. If you ensure that your program
invokes one of those functions before any other MySQL calls, there is
no need to invoke *Note `my_init()': my-init. explicitly.

To access the prototype for *Note `my_init()': my-init, your program
should include these header files:

     #include <my_global.h>
     #include <my_sys.h>

* Return Values *

None.


File: manual.info,  Node: mysql-thread-end,  Next: mysql-thread-init,  Prev: my-init,  Up: c-api-thread-functions

20.8.8.2 `mysql_thread_end()'
.............................

`void mysql_thread_end(void)'

* Description *

This function needs to be called before calling `pthread_exit()' to
free memory allocated by *Note `mysql_thread_init()': mysql-thread-init.

*Note `mysql_thread_end()': mysql-thread-end. _is not invoked
automatically by the client library_. It must be called explicitly to
avoid a memory leak.

* Return Values *

None.


File: manual.info,  Node: mysql-thread-init,  Next: mysql-thread-safe,  Prev: mysql-thread-end,  Up: c-api-thread-functions

20.8.8.3 `mysql_thread_init()'
..............................

`my_bool mysql_thread_init(void)'

* Description *

This function must be called early within each created thread to
initialize thread-specific variables. However, you may not necessarily
need to invoke it explicitly: *Note `mysql_thread_init()':
mysql-thread-init. is automatically called by *Note `my_init()':
my-init, which itself is automatically called by *Note `mysql_init()':
mysql-init, *Note `mysql_library_init()': mysql-library-init, *Note
`mysql_server_init()': mysql-server-init, and *Note `mysql_connect()':
mysql-connect. If you invoke any of those functions, *Note
`mysql_thread_init()': mysql-thread-init. will be called for you.

* Return Values *

Zero if successful. Nonzero if an error occurred.


File: manual.info,  Node: mysql-thread-safe,  Prev: mysql-thread-init,  Up: c-api-thread-functions

20.8.8.4 `mysql_thread_safe()'
..............................

`unsigned int mysql_thread_safe(void)'

* Description *

This function indicates whether the client library is compiled as
thread-safe.

* Return Values *

1 if the client library is thread-safe, 0 otherwise.


File: manual.info,  Node: c-api-embedded-server-functions,  Next: c-api-problems,  Prev: c-api-thread-functions,  Up: c

20.8.9 C API Embedded Server Function Descriptions
--------------------------------------------------

* Menu:

* mysql-server-init::            `mysql_server_init()'
* mysql-server-end::             `mysql_server_end()'

MySQL applications can be written to use an embedded server. See *Note
libmysqld::. To write such an application, you must link it against the
`libmysqld' library by using the `-lmysqld' flag rather than linking it
against the `libmysqlclient' client library by using the
`-lmysqlclient' flag. However, the calls to initialize and finalize the
library are the same whether you write a client application or one that
uses the embedded server: Call *Note `mysql_library_init()':
mysql-library-init. to initialize the library and *Note
`mysql_library_end()': mysql-library-end. when you are done with it.
See *Note c-api-function-overview::.

*Note `mysql_library_init()': mysql-library-init. and *Note
`mysql_library_end()': mysql-library-end. are available as of MySQL
5.0.3. For earlier versions of MySQL 5.0, call *Note
`mysql_server_init()': mysql-server-init. and *Note
`mysql_server_end()': mysql-server-end. instead, which are equivalent.
*Note `mysql_library_init()': mysql-library-init. and *Note
`mysql_library_end()': mysql-library-end. actually are `#define'
symbols that make them equivalent to *Note `mysql_server_init()':
mysql-server-init. and *Note `mysql_server_end()': mysql-server-end,
but the names more clearly indicate that they should be called when
beginning and ending use of a MySQL C API library no matter whether the
application uses `libmysqlclient' or `libmysqld'.


File: manual.info,  Node: mysql-server-init,  Next: mysql-server-end,  Prev: c-api-embedded-server-functions,  Up: c-api-embedded-server-functions

20.8.9.1 `mysql_server_init()'
..............................

`int mysql_server_init(int argc, char **argv, char **groups)'

* Description *

This function initializes the MySQL library, which must be done before
you call any other MySQL function.

As of MySQL 5.0.3, *Note `mysql_server_init()': mysql-server-init. is
deprecated and you should call *Note `mysql_library_init()':
mysql-library-init. instead.  See *Note mysql-library-init::.

* Return Values *

Zero if successful. Nonzero if an error occurred.


File: manual.info,  Node: mysql-server-end,  Prev: mysql-server-init,  Up: c-api-embedded-server-functions

20.8.9.2 `mysql_server_end()'
.............................

`void mysql_server_end(void)'

* Description *

This function finalizes the MySQL library. You should call it when you
are done using the library.

As of MySQL 5.0.3, *Note `mysql_server_end()': mysql-server-end. is
deprecated and you should call *Note `mysql_library_end()':
mysql-library-end. instead. See *Note mysql-library-end::.

* Return Values *

None.


File: manual.info,  Node: c-api-problems,  Next: auto-reconnect,  Prev: c-api-embedded-server-functions,  Up: c

20.8.10 Common Questions and Problems When Using the C API
----------------------------------------------------------

* Menu:

* null-mysql-store-result::      Why `mysql_store_result()' Sometimes Returns `NULL' After `mysql_query()' Returns Success
* query-results::                What Results You Can Get from a Query
* getting-unique-id::            How to Get the Unique ID for the Last Inserted Row


File: manual.info,  Node: null-mysql-store-result,  Next: query-results,  Prev: c-api-problems,  Up: c-api-problems

20.8.10.1 Why `mysql_store_result()' Sometimes Returns `NULL' After `mysql_query()' Returns Success
...................................................................................................

It is possible for *Note `mysql_store_result()': mysql-store-result. to
return `NULL' following a successful call to *Note `mysql_query()':
mysql-query. When this happens, it means one of the following
conditions occurred:

   * There was a `malloc()' failure (for example, if the result set was
     too large).

   * The data couldn't be read (an error occurred on the connection).

   * The query returned no data (for example, it was an *Note `INSERT':
     insert, *Note `UPDATE': update, or *Note `DELETE': delete.).

You can always check whether the statement should have produced a
nonempty result by calling *Note `mysql_field_count()':
mysql-field-count. If *Note `mysql_field_count()': mysql-field-count.
returns zero, the result is empty and the last query was a statement
that does not return values (for example, an *Note `INSERT': insert. or
a *Note `DELETE': delete.). If *Note `mysql_field_count()':
mysql-field-count. returns a nonzero value, the statement should have
produced a nonempty result. See the description of the *Note
`mysql_field_count()': mysql-field-count. function for an example.

You can test for an error by calling *Note `mysql_error()':
mysql-error. or *Note `mysql_errno()': mysql-errno.


File: manual.info,  Node: query-results,  Next: getting-unique-id,  Prev: null-mysql-store-result,  Up: c-api-problems

20.8.10.2 What Results You Can Get from a Query
...............................................

In addition to the result set returned by a query, you can also get the
following information:

   * *Note `mysql_affected_rows()': mysql-affected-rows.  returns the
     number of rows affected by the last query when doing an *Note
     `INSERT': insert, *Note `UPDATE': update, or *Note `DELETE':
     delete.

     For a fast re-create, use *Note `TRUNCATE TABLE': truncate-table.

   * *Note `mysql_num_rows()': mysql-num-rows. returns the number of
     rows in a result set. With *Note `mysql_store_result()':
     mysql-store-result, *Note `mysql_num_rows()': mysql-num-rows. may
     be called as soon as *Note `mysql_store_result()':
     mysql-store-result.  returns. With *Note `mysql_use_result()':
     mysql-use-result, *Note `mysql_num_rows()': mysql-num-rows. may be
     called only after you have fetched all the rows with *Note
     `mysql_fetch_row()': mysql-fetch-row.

   * *Note `mysql_insert_id()': mysql-insert-id. returns the ID
     generated by the last query that inserted a row into a table with
     an `AUTO_INCREMENT' index. See *Note mysql-insert-id::.

   * Some queries (*Note `LOAD DATA INFILE ...': load-data, *Note
     `INSERT INTO ... SELECT ...': insert-select, *Note `UPDATE':
     update.) return additional information. The result is returned by
     *Note `mysql_info()': mysql-info. See the description for *Note
     `mysql_info()': mysql-info.  for the format of the string that it
     returns.  *Note `mysql_info()': mysql-info. returns a `NULL'
     pointer if there is no additional information.


File: manual.info,  Node: getting-unique-id,  Prev: query-results,  Up: c-api-problems

20.8.10.3 How to Get the Unique ID for the Last Inserted Row
............................................................

If you insert a record into a table that contains an `AUTO_INCREMENT'
column, you can obtain the value stored into that column by calling the
*Note `mysql_insert_id()': mysql-insert-id. function.

You can check from your C applications whether a value was stored in an
`AUTO_INCREMENT' column by executing the following code (which assumes
that you've checked that the statement succeeded). It determines
whether the query was an *Note `INSERT': insert. with an
`AUTO_INCREMENT' index:

     if ((result = mysql_store_result(&mysql)) == 0 &&
         mysql_field_count(&mysql) == 0 &&
         mysql_insert_id(&mysql) != 0)
     {
         used_id = mysql_insert_id(&mysql);
     }

When a new `AUTO_INCREMENT' value has been generated, you can also
obtain it by executing a `SELECT LAST_INSERT_ID()' statement with *Note
`mysql_query()': mysql-query. and retrieving the value from the result
set returned by the statement.

For `LAST_INSERT_ID()', the most recently generated ID is maintained in
the server on a per-connection basis. It is not changed by another
client. It is not even changed if you update another `AUTO_INCREMENT'
column with a nonmagic value (that is, a value that is not `NULL' and
not `0'). Using `LAST_INSERT_ID()' and `AUTO_INCREMENT' columns
simultaneously from multiple clients is perfectly valid. Each client
will receive the last inserted ID for the last statement _that_ client
executed.

If you want to use the ID that was generated for one table and insert
it into a second table, you can use SQL statements like this:

     INSERT INTO foo (auto,text)
         VALUES(NULL,'text');         # generate ID by inserting NULL
     INSERT INTO foo2 (id,text)
         VALUES(LAST_INSERT_ID(),'text');  # use ID in second table

Note that *Note `mysql_insert_id()': mysql-insert-id.  returns the
value stored into an `AUTO_INCREMENT' column, whether that value is
automatically generated by storing `NULL' or `0' or was specified as an
explicit value.  `LAST_INSERT_ID()' returns only automatically
generated `AUTO_INCREMENT' values. If you store an explicit value other
than `NULL' or `0', it does not affect the value returned by
`LAST_INSERT_ID()'.

For more information on obtaining the last ID in an `AUTO_INCREMENT'
column:

   * For information on `LAST_INSERT_ID()', which can be used within an
     SQL statement, see *Note information-functions::.

   * For information on *Note `mysql_insert_id()': mysql-insert-id, the
     function you use from within the C API, see *Note
     mysql-insert-id::.

   * For information on obtaining the auto-incremented value when using
     Connector/J see *Note connector-j-usagenotes::.

   * For information on obtaining the auto-incremented value when using
     Connector/ODBC see *Note
     connector-odbc-usagenotes-functionality-last-insert-id::.


File: manual.info,  Node: auto-reconnect,  Next: c-api-multiple-queries,  Prev: c-api-problems,  Up: c

20.8.11 Controlling Automatic Reconnection Behavior
---------------------------------------------------

The MySQL client library can perform an automatic reconnection to the
server if it finds that the connection is down when you attempt to send
a statement to the server to be executed. In this case, the library
tries once to reconnect to the server and send the statement again.

If it is important for your application to know that the connection has
been dropped (so that is can exit or take action to adjust for the loss
of state information), be sure that auto-reconnect is disabled. To
ensure this, call *Note `mysql_options()': mysql-options. with the
`MYSQL_OPT_RECONNECT' option:

     my_bool reconnect = 0;
     mysql_options(&mysql, MYSQL_OPT_RECONNECT, &reconnect);

In MySQL 5.0, auto-reconnect was enabled by default until MySQL 5.0.3,
and disabled by default thereafter. The `MYSQL_OPT_RECONNECT' option is
available as of MySQL 5.0.13.

If the connection has gone down, the effect of *Note `mysql_ping()':
mysql-ping. depends on the auto-reconnect state. If auto-reconnect is
enabled, *Note `mysql_ping()': mysql-ping. performs a reconnect.
Otherwise, it returns an error.

Some client programs might provide the capability of controlling
automatic reconnection. For example, *Note `mysql': mysql.  reconnects
by default, but the `--skip-reconnect' option can be used to suppress
this behavior.

If an automatic reconnection does occur (for example, as a result of
calling *Note `mysql_ping()': mysql-ping.), there is no explicit
indication of it. To check for reconnection, call *Note
`mysql_thread_id()': mysql-thread-id. to get the original connection
identifier before calling *Note `mysql_ping()': mysql-ping, then call
*Note `mysql_thread_id()': mysql-thread-id. again to see whether the
identifier has changed.

Automatic reconnection can be convenient because you need not implement
your own reconnect code, but if a reconnection does occur, several
aspects of the connection state are reset on the server side and your
application will not know about it. The connection-related state is
affected as follows:

   * Any active transactions are rolled back and autocommit mode is
     reset.

   * All table locks are released.

   * All `TEMPORARY' tables are closed (and dropped).

   * Session variables are reinitialized to the values of the
     corresponding variables. This also affects variables that are set
     implicitly by statements such as `SET NAMES'.

   * User variable settings are lost.

   * Prepared statements are released.

   * *Note `HANDLER': handler. variables are closed.

   * The value of `LAST_INSERT_ID()' is reset to 0.

   * Locks acquired with `GET_LOCK()' are released.

If the connection drops, it is possible that the session associated
with the connection on the server side will still be running if the
server has not yet detected that the client is no longer connected. In
this case, any locks held by the original connection still belong to
that session, so you may want to kill it by calling *Note
`mysql_kill()': mysql-kill.


File: manual.info,  Node: c-api-multiple-queries,  Next: c-api-prepared-statement-problems,  Prev: auto-reconnect,  Up: c

20.8.12 C API Support for Multiple Statement Execution
------------------------------------------------------

By default, *Note `mysql_query()': mysql-query. and *Note
`mysql_real_query()': mysql-real-query. interpret their statement
string argument as a single statement to be executed, and you process
the result according to whether the statement produces a result set (a
set of rows, as for *Note `SELECT': select.) or an affected-rows count
(as for *Note `INSERT': insert, *Note `UPDATE': update, and so forth).

MySQL 5.0 also supports the execution of a string containing multiple
statements separated by semicolon (``;'') characters. This capability
is enabled by special options that are specified either when you
connect to the server with *Note `mysql_real_connect()':
mysql-real-connect. or after connecting by calling` *Note
`mysql_set_server_option()': mysql-set-server-option.

Executing a multiple-statement string can produce multiple result sets
or row-count indicators. Processing these results involves a different
approach than for the single-statement case: After handling the result
from the first statement, it is necessary to check whether more results
exist and process them in turn if so.  To support multiple-result
processing, the C API includes the *Note `mysql_more_results()':
mysql-more-results. and *Note `mysql_next_result()': mysql-next-result.
functions.  These functions are used at the end of a loop that iterates
as long as more results are available. _Failure to process the result
this way may result in a dropped connection to the server._

Multiple-result processing also is required if you execute *Note
`CALL': call. statements for stored procedures. Results from a stored
procedure have these characteristics:

   * Statements within the procedure may produce result sets (for
     example, if it executes *Note `SELECT': select.  statements).
     These result sets are returned in the order that they are produced
     as the procedure executes.

     In general, the caller cannot know how many result sets a
     procedure will return. Procedure execution may depend on loops or
     conditional statements that cause the execution path to differ
     from one call to the next. Therefore, you must be prepared to
     retrieve multiple results.

   * The final result from the procedure is a status result that
     includes no result set. The status indicates whether the procedure
     succeeded or an error occurred.

The multiple statement and result capabilities can be used only with
*Note `mysql_query()': mysql-query. or *Note `mysql_real_query()':
mysql-real-query. They cannot be used with the prepared statement
interface. Prepared statement handles are defined to work only with
strings that contain a single statement. See *Note
c-api-prepared-statements::.

To enable multiple-statement execution and result processing, the
following options may be used:

   * The *Note `mysql_real_connect()': mysql-real-connect.  function
     has a `flags' argument for which two option values are relevant:

        * `CLIENT_MULTI_RESULTS' enables the client program to process
          multiple results. This option _must_ be enabled if you execute
          *Note `CALL': call. statements for stored procedures that
          produce result sets. Otherwise, such procedures result in an
          error `Error 1312 (0A000): PROCEDURE PROC_NAME can't return a
          result set in the given context'.

        * `CLIENT_MULTI_STATEMENTS' enables *Note `mysql_query()':
          mysql-query. and *Note `mysql_real_query()':
          mysql-real-query. to execute statement strings containing
          multiple statements separated by semicolons. This option also
          enables `CLIENT_MULTI_RESULTS' implicitly, so a `flags'
          argument of `CLIENT_MULTI_STATEMENTS' to *Note
          `mysql_real_connect()': mysql-real-connect. is equivalent to
          an argument of `CLIENT_MULTI_STATEMENTS |
          CLIENT_MULTI_RESULTS'. That is, `CLIENT_MULTI_STATEMENTS' is
          sufficient to enable multiple-statement execution and all
          multiple-result processing.

   * After the connection to the server has been established, you can
     use the *Note `mysql_set_server_option()': mysql-set-server-option.
     function to enable or disable multiple-statement execution by
     passing it an argument of `MYSQL_OPTION_MULTI_STATEMENTS_ON' or
     `MYSQL_OPTION_MULTI_STATEMENTS_OFF'. Enabling multiple-statement
     execution with this function also enables processing of `simple'
     results for a multiple-statement string where each statement
     produces a single result, but is _not_ sufficient to permit
     processing of stored procedures that produce result sets.

The following procedure outlines a suggested strategy for handling
multiple statements:

  1. Pass `CLIENT_MULTI_STATEMENTS' to *Note `mysql_real_connect()':
     mysql-real-connect, to fully enable multiple-statement execution
     and multiple-result processing.

  2. After calling *Note `mysql_query()': mysql-query. or *Note
     `mysql_real_query()': mysql-real-query. and verifying that it
     succeeds, enter a loop within which you process statement results.

  3. For each iteration of the loop, handle the current statement
     result, retrieving either a result set or an affected-rows count.
     If an error occurs, exit the loop.

  4. At the end of the loop, call *Note `mysql_next_result()':
     mysql-next-result. to check whether another result exists and
     initiate retrieval for it if so. If no more results are available,
     exit the loop.

One possible implementation of the preceding strategy is shown
following. The final part of the loop can be reduced to a simple test
of whether *Note `mysql_next_result()': mysql-next-result. returns
nonzero. The code as written distinguishes between no more results and
an error, which enables a message to be printed for the latter
occurrence.

     /* connect to server with the CLIENT_MULTI_STATEMENTS option */
     if (mysql_real_connect (mysql, host_name, user_name, password,
         db_name, port_num, socket_name, CLIENT_MULTI_STATEMENTS) == NULL)
     {
       printf("mysql_real_connect() failed\n");
       mysql_close(mysql);
       exit(1);
     }

     /* execute multiple statements */
     status = mysql_query(mysql,
                          "DROP TABLE IF EXISTS test_table;\
                           CREATE TABLE test_table(id INT);\
                           INSERT INTO test_table VALUES(10);\
                           UPDATE test_table SET id=20 WHERE id=10;\
                           SELECT * FROM test_table;\
                           DROP TABLE test_table");
     if (status)
     {
       printf("Could not execute statement(s)");
       mysql_close(mysql);
       exit(0);
     }

     /* process each statement result */
     do {
       /* did current statement return data? */
       result = mysql_store_result(mysql);
       if (result)
       {
         /* yes; process rows and free the result set */
         process_result_set(mysql, result);
         mysql_free_result(result);
       }
       else          /* no result set or error */
       {
         if (mysql_field_count(mysql) == 0)
         {
           printf("%lld rows affected\n",
                 mysql_affected_rows(mysql));
         }
         else  /* some error occurred */
         {
           printf("Could not retrieve result set\n");
           break;
         }
       }
       /* more results? -1 = no, >0 = error, 0 = yes (keep looping) */
       if ((status = mysql_next_result(mysql)) > 0)
         printf("Could not execute statement\n");
     } while (status == 0);

     mysql_close(mysql);


File: manual.info,  Node: c-api-prepared-statement-problems,  Next: c-api-prepared-statement-date-handling,  Prev: c-api-multiple-queries,  Up: c

20.8.13 C API Prepared Statement Problems
-----------------------------------------

Here follows a list of the currently known problems with prepared
statements:

   * *Note `TIME': time, *Note `TIMESTAMP': datetime, and *Note
     `DATETIME': datetime. do not support parts of seconds (for
     example, from `DATE_FORMAT()').

   * When converting an integer to string, `ZEROFILL' is honored with
     prepared statements in some cases where the MySQL server doesn't
     print the leading zeros. (For example, with
     `MIN(NUMBER-WITH-ZEROFILL)').

   * When converting a floating-point number to a string in the client,
     the rightmost digits of the converted value may differ slightly
     from those of the original value.

   * _Prepared statements do not use the query cache, even in cases
     where a query does not contain any placeholders_. See *Note
     query-cache-operation::.

   * Prepared statements do not support multi-statements (that is,
     multiple statements within a single string separated by ``;''
     characters).

   * In MySQL 5.0, prepared *Note `CALL': call. statements cannot invoke
     stored procedures that return result sets because prepared
     statements do not support multiple result sets. Nor can the
     calling application access a stored procedure's `OUT' or `INOUT'
     parameters when the procedure returns. These capabilities are
     supported beginning with MySQL 5.5.


File: manual.info,  Node: c-api-prepared-statement-date-handling,  Next: c-api-prepared-call-statements,  Prev: c-api-prepared-statement-problems,  Up: c

20.8.14 C API Prepared Statement Handling of Date and Time Values
-----------------------------------------------------------------

The binary (prepared statement) protocol enables you to send and
receive date and time values (*Note `DATE': datetime, *Note `TIME':
time, *Note `DATETIME': datetime, and *Note `TIMESTAMP': datetime.),
using the `MYSQL_TIME' structure. The members of this structure are
described in *Note c-api-prepared-statement-data-structures::.

To send temporal data values, create a prepared statement using *Note
`mysql_stmt_prepare()': mysql-stmt-prepare. Then, before calling *Note
`mysql_stmt_execute()': mysql-stmt-execute. to execute the statement,
use the following procedure to set up each temporal parameter:

  1. In the `MYSQL_BIND' structure associated with the data value, set
     the `buffer_type' member to the type that indicates what kind of
     temporal value you're sending. For *Note `DATE': datetime, *Note
     `TIME': time, *Note `DATETIME': datetime, or *Note `TIMESTAMP':
     datetime. values, set `buffer_type' to `MYSQL_TYPE_DATE',
     `MYSQL_TYPE_TIME', `MYSQL_TYPE_DATETIME', or
     `MYSQL_TYPE_TIMESTAMP', respectively.

  2. Set the `buffer' member of the `MYSQL_BIND' structure to the
     address of the `MYSQL_TIME' structure in which you pass the
     temporal value.

  3. Fill in the members of the `MYSQL_TIME' structure that are
     appropriate for the type of temporal value to be passed.

Use *Note `mysql_stmt_bind_param()': mysql-stmt-bind-param. to bind the
parameter data to the statement. Then you can call *Note
`mysql_stmt_execute()': mysql-stmt-execute.

To retrieve temporal values, the procedure is similar, except that you
set the `buffer_type' member to the type of value you expect to
receive, and the `buffer' member to the address of a `MYSQL_TIME'
structure into which the returned value should be placed. Use *Note
`mysql_stmt_bind_result()': mysql-stmt-bind-result. to bind the buffers
to the statement after calling *Note `mysql_stmt_execute()':
mysql-stmt-execute. and before fetching the results.

Here is a simple example that inserts *Note `DATE': datetime, *Note
`TIME': time, and *Note `TIMESTAMP': datetime. data. The `mysql'
variable is assumed to be a valid connection handle.


       MYSQL_TIME  ts;
       MYSQL_BIND  bind[3];
       MYSQL_STMT  *stmt;

       strmov(query, "INSERT INTO test_table(date_field, time_field, \
                                    timestamp_field) VALUES(?,?,?");

       stmt = mysql_stmt_init(mysql);
       if (!stmt)
       {
         fprintf(stderr, " mysql_stmt_init(), out of memory\n");
         exit(0);
       }
       if (mysql_stmt_prepare(mysql, query, strlen(query)))
       {
         fprintf(stderr, "\n mysql_stmt_prepare(), INSERT failed");
         fprintf(stderr, "\n %s", mysql_stmt_error(stmt));
         exit(0);
       }

       /* set up input buffers for all 3 parameters */
       bind[0].buffer_type= MYSQL_TYPE_DATE;
       bind[0].buffer= (char *)&ts;
       bind[0].is_null= 0;
       bind[0].length= 0;
       ...
       bind[1]= bind[2]= bind[0];
       ...

       mysql_stmt_bind_param(stmt, bind);

       /* supply the data to be sent in the ts structure */
       ts.year= 2002;
       ts.month= 02;
       ts.day= 03;

       ts.hour= 10;
       ts.minute= 45;
       ts.second= 20;

       mysql_stmt_execute(stmt);
       ..


File: manual.info,  Node: c-api-prepared-call-statements,  Next: building-clients,  Prev: c-api-prepared-statement-date-handling,  Up: c

20.8.15 C API Support for Prepared `CALL' Statements
----------------------------------------------------

In MySQL 5.0, prepared *Note `CALL': call. statements can be used only
for stored procedures that produce at most one result set. Nor can the
calling application use placeholders for `OUT' or `INOUT' parameters.

MySQL 5.5 expands prepared *Note `CALL': call.  statement support for
stored procedures that produce multiple result sets and to provide
placeholder access to `OUT' and `INOUT' parameters.


File: manual.info,  Node: building-clients,  Prev: c-api-prepared-call-statements,  Up: c

20.8.16 Building Client Programs
--------------------------------

* Menu:

* c-api-linking-problems::       Problems Linking to the MySQL Client Library
* threaded-clients::             How to Write a Threaded Client

If you compile MySQL clients that you've written yourself or that you
obtain from a third-party, they must be linked using the `-lmysqlclient
-lz' options in the link command.  You may also need to specify a `-L'
option to tell the linker where to find the library. For example, if
the library is installed in `/usr/local/mysql/lib', use
`-L/usr/local/mysql/lib -lmysqlclient -lz' in the link command.

For clients that use MySQL header files, you may need to specify an
`-I' option when you compile them (for example,
`-I/usr/local/mysql/include'), so that the compiler can find the header
files.

* Compiling MySQL Clients on Unix *

To make it simpler to compile MySQL programs on Unix, we have provided
the *Note `mysql_config': mysql-config. script for you. See *Note
mysql-config::.

You can use it to compile a MySQL client as follows:

     CFG=/usr/local/mysql/bin/mysql_config
     sh -c "gcc -o progname `$CFG --cflags` progname.c `$CFG --libs`"

The `sh -c' is needed to get the shell not to treat the output from
*Note `mysql_config': mysql-config. as one word.

* Compiling MySQL Clients on Microsoft Windows *

On Windows, you can link your code with either the dynamic or static
client library. The static library is named `mysqlclient' and the
dynamic library is named `libmysql'.

If you link with the static library, failure can occur if certain
conditions are not satisfied:

   * The client application must be compiled with exactly the same
     version of Visual Studio as that used to compile the library.

   * The client application should link the C runtime statically by
     using the `/MT' compiler option.

If the client application is built in in debug mode and uses the static
debug C runtime (`/MTd' compiler option), it can link the `mysqlclient'
if that library was built using the same option. If the client
application uses the dynamic C runtime (`/MD' option, or `/MDd' option
in debug mode), it cannot link with the static client library and must
use the dynamic library.

The MSDN page describing the link options can be found here:
`http://msdn.microsoft.com/en-us/library/2kzt1wy3.aspx'


File: manual.info,  Node: c-api-linking-problems,  Next: threaded-clients,  Prev: building-clients,  Up: building-clients

20.8.16.1 Problems Linking to the MySQL Client Library
......................................................

When linking with the C API, the following errors may occur on some
systems:

     gcc -g -o client test.o -L/usr/local/lib/mysql \
                             -lmysqlclient -lsocket -lnsl

     Undefined        first referenced
      symbol          in file
     floor            /usr/local/lib/mysql/libmysqlclient.a(password.o)
     ld: fatal: Symbol referencing errors. No output written to client

If this happens on your system, you must include the math library by
adding `-lm' to the end of the compile/link line.

Linking with the single-threaded library (`libmysqlclient') may lead to
linker errors related to `pthread' symbols. When using the
single-threaded library, please compile your client with
`MYSQL_CLIENT_NO_THREADS' defined. This can be done on the command line
by using the `-D' option to the compiler, or in your source code before
including the MySQL header files. This define should not be used when
building for use with the thread-safe client library
(`libmysqlclient_r').

When you are linking an application program to use the MySQL client
library, you might get undefined reference errors for symbols that
start with `mysql_', such as those shown here:

     /tmp/ccFKsdPa.o: In function `main':
     /tmp/ccFKsdPa.o(.text+0xb): undefined reference to `mysql_init'
     /tmp/ccFKsdPa.o(.text+0x31): undefined reference to `mysql_real_connect'
     /tmp/ccFKsdPa.o(.text+0x57): undefined reference to `mysql_real_connect'
     /tmp/ccFKsdPa.o(.text+0x69): undefined reference to `mysql_error'
     /tmp/ccFKsdPa.o(.text+0x9a): undefined reference to `mysql_close'

You should be able to solve this problem by adding `-Ldir_path
-lmysqlclient' at the end of your link command, where `dir_path'
represents the path name of the directory where the client library is
located.  To determine the correct directory, try this command:

     shell> mysql_config --libs

The output from *Note `mysql_config': mysql-config. might indicate
other libraries that should be specified on the link command as well.

If you get `undefined reference' errors for the `uncompress' or
`compress' function, add `-lz' to the end of your link command and try
again.

If you get `undefined reference' errors for a function that should
exist on your system, such as `connect', check the manual page for the
function in question to determine which libraries you should add to the
link command.

You might get `undefined reference' errors such as the following for
functions that don't exist on your system:

     mf_format.o(.text+0x201): undefined reference to `__lxstat'

This usually means that your MySQL client library was compiled on a
system that is not 100% compatible with yours. In this case, you should
download the latest MySQL source distribution and compile MySQL
yourself. See *Note source-installation::.

You might get undefined reference errors at runtime when you try to
execute a MySQL program. If these errors specify symbols that start
with `mysql_' or indicate that the `mysqlclient' library can't be
found, it means that your system can't find the shared
`libmysqlclient.so' library. The fix for this is to tell your system to
search for shared libraries where the library is located. Use whichever
of the following methods is appropriate for your system:

   * Add the path to the directory where `libmysqlclient.so' is located
     to the `LD_LIBRARY_PATH' environment variable.

   * Add the path to the directory where `libmysqlclient.so' is located
     to the `LD_LIBRARY' environment variable.

   * Copy `libmysqlclient.so' to some directory that is searched by
     your system, such as `/lib', and update the shared library
     information by executing `ldconfig'.

Another way to solve this problem is by linking your program statically
with the `-static' option, or by removing the dynamic MySQL libraries
before linking your code.  Before trying the second method, you should
be sure that no other programs are using the dynamic libraries.


File: manual.info,  Node: threaded-clients,  Prev: c-api-linking-problems,  Up: building-clients

20.8.16.2 How to Write a Threaded Client
........................................

The client library is almost thread-safe. The biggest problem is that
the subroutines in `net.c' that read from sockets are not interrupt
safe. This was done with the thought that you might want to have your
own alarm that can break a long read to a server. If you install
interrupt handlers for the `SIGPIPE' interrupt, the socket handling
should be thread-safe.

To avoid aborting the program when a connection terminates, MySQL
blocks `SIGPIPE' on the first call to *Note `mysql_library_init()':
mysql-library-init, *Note `mysql_init()': mysql-init, or *Note
`mysql_connect()': mysql-connect. If you want to use your own `SIGPIPE'
handler, you should first call *Note `mysql_library_init()':
mysql-library-init.  and then install your handler.

Current binary distributions should have both a normal client library,
`libmysqlclient', and a thread-safe library, `libmysqlclient_r'. For
threaded clients, link against the latter library. If `undefined
symbol' errors occur, in most cases this is because you have not
included the thread libraries on the link/compile command.

The thread-safe client library, `libmysqlclient_r', is thread-safe per
connection. You can let two threads share the same connection with the
following caveats:

   * Two threads can't send a query to the MySQL server at the same
     time on the same connection. In particular, you have to ensure
     that between calls to *Note `mysql_query()': mysql-query. and
     *Note `mysql_store_result()': mysql-store-result, no other thread
     is using the same connection.

   * Many threads can access different result sets that are retrieved
     with *Note `mysql_store_result()': mysql-store-result.

   * If you use *Note `mysql_use_result()': mysql-use-result, you must
     ensure that no other thread is using the same connection until the
     result set is closed. However, it really is best for threaded
     clients that share the same connection to use *Note
     `mysql_store_result()': mysql-store-result.

   * If you want to use multiple threads on the same connection, you
     must have a mutex lock around your pair of *Note `mysql_query()':
     mysql-query. and *Note `mysql_store_result()': mysql-store-result.
     calls.  Once *Note `mysql_store_result()': mysql-store-result. is
     ready, the lock can be released and other threads may query the
     same connection.

   * If you use POSIX threads, you can use `pthread_mutex_lock()' and
     `pthread_mutex_unlock()' to establish and release a mutex lock.

You need to know the following if you have a thread that did not create
the connection to the MySQL database but is calling MySQL functions:

When you call *Note `mysql_init()': mysql-init, MySQL creates a
thread-specific variable for the thread that is used by the debug
library (among other things). If you call a MySQL function before the
thread has called *Note `mysql_init()': mysql-init, the thread does not
have the necessary thread-specific variables in place and you are
likely to end up with a core dump sooner or later. To avoid problems,
you must do the following:

  1. Call *Note `mysql_library_init()': mysql-library-init.  before any
     other MySQL functions. It is not thread-safe, so call it before
     threads are created, or protect the call with a mutex.

  2. Arrange for *Note `mysql_thread_init()': mysql-thread-init. to be
     called early in the thread handler before calling any MySQL
     function. If you call *Note `mysql_init()': mysql-init, it will
     call *Note `mysql_thread_init()': mysql-thread-init. for you.

  3. In the thread, call *Note `mysql_thread_end()': mysql-thread-end.
     before calling `pthread_exit()'. This frees the memory used by
     MySQL thread-specific variables.

The preceding notes regarding *Note `mysql_init()': mysql-init. also
apply to *Note `mysql_connect()': mysql-connect, which calls *Note
`mysql_init()': mysql-init.


File: manual.info,  Node: apis-php,  Next: apis-perl,  Prev: c,  Up: connectors-apis

20.9 MySQL PHP API
==================

* Menu:

* connector-php::                Connector/PHP
* apis-php-problems::            Common Problems with MySQL and PHP
* php-mysql-mysqli::             Enabling Both `mysql' and `mysqli' in PHP

PHP is a server-side, HTML-embedded scripting language that may be used
to create dynamic Web pages. It is available for most operating systems
and Web servers, and can access most common databases, including MySQL.
PHP may be run as a separate program or compiled as a module for use
with the Apache Web server.

PHP actually provides two different MySQL API extensions:

   * `mysql': Available for PHP versions 4 and 5, this extension is
     intended for use with MySQL versions prior to MySQL 4.1. This
     extension does not support the improved authentication protocol
     used in MySQL 4.1, nor does it support prepared statements or
     multiple statements. To use this extension with MySQL 4.1, you
     will likely configure the MySQL server to use the
     `--old-passwords' option (see *Note old-client::). This extension
     is documented on the PHP Web site at `http://php.net/mysql'.

   * See section "apis-php-mysqli" in the online manual - Stands for
     `MySQL, Improved'; this extension is available only in PHP 5. It
     is intended for use with MySQL 4.1.1 and later. This extension
     fully supports the authentication protocol used in MySQL 5.0, as
     well as the Prepared Statements and Multiple Statements APIs. In
     addition, this extension provides an advanced, object-oriented
     programming interface. You can read the documentation for the
     `mysqli' extension at `http://php.net/mysqli'. Helpful article can
     be found at `http://devzone.zend.com/node/view/id/686' and
     `http://devzone.zend.com/node/view/id/687'.

If you're experiencing problems with enabling both the `mysql' and the
`mysqli' extension when building PHP on Linux yourself, see *Note
php-mysql-mysqli::.

The PHP distribution and documentation are available from the PHP Web
site (http://www.php.net/).

_Portions of this section are Copyright (c) 1997-2008 the PHP
Documentation Group_ This material may be distributed only subject to
the terms and conditions set forth in the Creative Commons Attribution
3.0 License or later. A copy of the Creative Commons Attribution 3.0
license is distributed with this manual. The latest version is
presently available at This material may be distributed only subject to
the terms and conditio\ ns set forth in the Open Publication License,
v1.0.8 or later (the latest version is presently available at
http://www.opencontent.org/openpub/
(http://www.opencontent.org/openpub/)).


File: manual.info,  Node: connector-php,  Next: apis-php-problems,  Prev: apis-php,  Up: apis-php

20.9.1 Connector/PHP
--------------------

The MySQL Connector/PHP is a version of the `mysql' and `mysqli'
extensions for PHP optimized for the Windows operating system. Later
versions of the main PHP `mysql'/`mysqli' drivers are compatible with
Windows and a separate, Windows specific driver is no longer required.

For PHP for all platforms, including Windows, you should use the
`mysql' or `mysqli' extensions shipped with the PHP sources. See *Note
apis-php::.


File: manual.info,  Node: apis-php-problems,  Next: php-mysql-mysqli,  Prev: connector-php,  Up: apis-php

20.9.2 Common Problems with MySQL and PHP
-----------------------------------------

   * `Error: Maximum Execution Time Exceeded': This is a PHP limit; go
     into the `php.ini' file and set the maximum execution time up from
     30 seconds to something higher, as needed. It is also not a bad
     idea to double the RAM allowed per script to 16MB instead of 8MB.

   * `Fatal error: Call to unsupported or undefined function
     mysql_connect() in ...': This means that your PHP version isn't
     compiled with MySQL support. You can either compile a dynamic
     MySQL module and load it into PHP or recompile PHP with built-in
     MySQL support. This process is described in detail in the PHP
     manual.

   * `Error: Undefined reference to 'uncompress'': This means that the
     client library is compiled with support for a compressed
     client/server protocol. The fix is to add `-lz' last when linking
     with `-lmysqlclient'.

   * `Error: Client does not support authentication protocol': This is
     most often encountered when trying to use the older `mysql'
     extension with MySQL 4.1.1 and later. Possible solutions are:
     downgrade to MySQL 4.0; switch to PHP 5 and the newer `mysqli'
     extension; or configure the MySQL server with `--old-passwords'.
     (See *Note old-client::, for more information.)

Those with PHP4 legacy code can make use of a compatibility layer for
the old and new MySQL libraries, such as this one:
`http://www.coggeshall.org/oss/mysql2i'.


File: manual.info,  Node: php-mysql-mysqli,  Prev: apis-php-problems,  Up: apis-php

20.9.3 Enabling Both `mysql' and `mysqli' in PHP
------------------------------------------------

If you're experiencing problems with enabling both the `mysql' and the
`mysqli' extension when building PHP on Linux yourself, you should try
the following procedure.

  1. Configure PHP like this:

          ./configure --with-mysqli=/usr/bin/mysql_config --with-mysql=/usr

  2. Edit the `Makefile' and search for a line that starts with
     `EXTRA_LIBS'. It might look like this (all on one line):

          EXTRA_LIBS = -lcrypt -lcrypt -lmysqlclient -lz -lresolv -lm -ldl -lnsl
          -lxml2 -lz -lm -lxml2 -lz -lm -lmysqlclient -lz -lcrypt -lnsl -lm
          -lxml2 -lz -lm -lcrypt -lxml2 -lz -lm -lcrypt

     Remove all duplicates, so that the line looks like this (all on
     one line):

          EXTRA_LIBS = -lcrypt -lcrypt -lmysqlclient -lz -lresolv -lm -ldl -lnsl
          -lxml2

  3. Build and install PHP:

          make
          make install


File: manual.info,  Node: apis-perl,  Next: apis-python,  Prev: apis-php,  Up: connectors-apis

20.10 MySQL Perl API
====================

The Perl `DBI' module provides a generic interface for database access.
You can write a DBI script that works with many different database
engines without change. To use DBI, you must install the `DBI' module,
as well as a DataBase Driver (DBD) module for each type of server you
want to access. For MySQL, this driver is the `DBD::mysql' module.

Perl DBI is the recommended Perl interface. It replaces an older
interface called `mysqlperl', which should be considered obsolete.

Installation instructions for Perl DBI support are given in *Note
perl-support::.

DBI information is available at the command line, online, or in printed
form:

   * Once you have the `DBI' and `DBD::mysql' modules installed, you
     can get information about them at the command line with the
     `perldoc' command:

          shell> perldoc DBI
          shell> perldoc DBI::FAQ
          shell> perldoc DBD::mysql

     You can also use `pod2man', `pod2html', and so forth to translate
     this information into other formats.

   * For online information about Perl DBI, visit the DBI Web site,
     `http://dbi.perl.org/'. That site hosts a general DBI mailing
     list. Oracle Corporation hosts a list specifically about
     `DBD::mysql'; see *Note mailing-lists::.

   * For printed information, the official DBI book is `Programming the
     Perl DBI' (Alligator Descartes and Tim Bunce, O'Reilly &
     Associates, 2000).  Information about the book is available at the
     DBI Web site, `http://dbi.perl.org/'.

     For information that focuses specifically on using DBI with MySQL,
     see `MySQL and Perl for the Web' (Paul DuBois, New Riders, 2001).
     This book's Web site is `http://www.kitebird.com/mysql-perl/'.


File: manual.info,  Node: apis-python,  Next: apis-ruby,  Prev: apis-perl,  Up: connectors-apis

20.11 MySQL Python API
======================

`MySQLdb' provides MySQL support for Python, compliant with the Python
DB API version 2.0. It can be found at
`http://sourceforge.net/projects/mysql-python/'.


File: manual.info,  Node: apis-ruby,  Next: apis-tcl,  Prev: apis-python,  Up: connectors-apis

20.12 MySQL Ruby APIs
=====================

* Menu:

* apis-ruby-mysqlruby::          The MySQL/Ruby API
* apis-ruby-rubymysql::          The Ruby/MySQL API

Two APIs available for Ruby programmers. The MySQL/Ruby API is based on
the `libmysql' API library. The Ruby/MySQL API is written to use the
native MySQL network protocol (a native driver).

For more information on Ruby, see Ruby Programming Language
(http://www.ruby-lang.org).

For information on installing and using the MySQL/Ruby API, see *Note
apis-ruby-mysqlruby::.

For information on installing and using the Ruby/MySQL API, see *Note
apis-ruby-rubymysql::.


File: manual.info,  Node: apis-ruby-mysqlruby,  Next: apis-ruby-rubymysql,  Prev: apis-ruby,  Up: apis-ruby

20.12.1 The MySQL/Ruby API
--------------------------

The MySQL/Ruby module provides access to MySQL databases using Ruby
through `libmysql'.

For information on installing the module, and the functions exposed, see
MySQL/Ruby (http://tmtm.org/en/mysql/ruby/).


File: manual.info,  Node: apis-ruby-rubymysql,  Prev: apis-ruby-mysqlruby,  Up: apis-ruby

20.12.2 The Ruby/MySQL API
--------------------------

The Ruby/MySQL module provides access to MySQL databases using Ruby
through a native driver interface using the MySQL network protocol.

For information on installing the module, and the functions exposed, see
Ruby/MySQL (http://tmtm.org/en/ruby/mysql/README_en.html).


File: manual.info,  Node: apis-tcl,  Next: apis-eiffel,  Prev: apis-ruby,  Up: connectors-apis

20.13 MySQL Tcl API
===================

`MySQLtcl' is a simple API for accessing a MySQL database server from
the Tcl programming language. It can be found at
`http://www.xdobry.de/mysqltcl/'.


File: manual.info,  Node: apis-eiffel,  Prev: apis-tcl,  Up: connectors-apis

20.14 MySQL Eiffel Wrapper
==========================

Eiffel MySQL is an interface to the MySQL database server using the
Eiffel programming language, written by Michael Ravits. It can be found
at `http://efsa.sourceforge.net/archive/ravits/mysql.htm'.


File: manual.info,  Node: extending-mysql,  Next: mysql-enterprise-monitor,  Prev: connectors-apis,  Up: Top

21 Extending MySQL
******************

* Menu:

* mysql-internals::              MySQL Internals
* adding-functions::             Adding New Functions to MySQL
* adding-procedures::            Adding New Procedures to MySQL
* porting::                      Debugging and Porting MySQL


File: manual.info,  Node: mysql-internals,  Next: adding-functions,  Prev: extending-mysql,  Up: extending-mysql

21.1 MySQL Internals
====================

* Menu:

* mysql-threads::                MySQL Threads
* mysql-test-suite::             The MySQL Test Suite

This chapter describes a lot of things that you need to know when
working on the MySQL code. To track or contribute to MySQL development,
follow the instructions in *Note installing-development-tree::. If you
are interested in MySQL internals, you should also subscribe to our
`internals' mailing list. This list has relatively low traffic. For
details on how to subscribe, please see *Note mailing-lists::. Many
MySQL developers at Oracle Corporation are on the `internals' list and
we help other people who are working on the MySQL code. Feel free to
use this list both to ask questions about the code and to send patches
that you would like to contribute to the MySQL project!


File: manual.info,  Node: mysql-threads,  Next: mysql-test-suite,  Prev: mysql-internals,  Up: mysql-internals

21.1.1 MySQL Threads
--------------------

The MySQL server creates the following threads:

   * Connection manager threads handle client connection requests on
     the network interfaces that the server listens to. On all
     platforms, one manager thread handles TCP/IP connection requests.
     On Unix, this manager thread also handles Unix socket file
     connection requests. On Windows, a manager thread handles
     shared-memory connection requests, and another handles named-pipe
     connection requests. The server does not create threads to handle
     interfaces that it does not listen to. For example, a Windows
     server that does not have support for named-pipe connections
     enabled does not create a thread to handle them.

   * Connection manager threads associate each client connection with a
     thread dedicated to it that handles authentication and request
     processing for that connection. Manager threads create a new
     thread when necessary but try to avoid doing so by consulting the
     thread cache first to see whether it contains a thread that can be
     used for the connection. When a connection ends, its thread is
     returned to the thread cache if the cache is not full.

     For information about tuning the parameters that control thread
     resources, see *Note connection-threads::.

   * On a master replication server, connections from slave servers are
     handled like client connections: There is one thread per connected
     slave.

   * On a slave replication server, an I/O thread is started to connect
     to the master server and read updates from it. An SQL thread is
     started to apply updates read from the master.  These two threads
     run independently and can be started and stopped independently.

   * A signal thread handles all signals. This thread also normally
     handles alarms and calls `process_alarm()' to force timeouts on
     connections that have been idle too long.

   * If `InnoDB' is used, there will be 4 additional threads by
     default. Those are file I/O threads, controlled by the
     `innodb_file_io_threads' parameter. See *Note innodb-parameters::.

   * If *Note `mysqld': mysqld. is compiled with `-DUSE_ALARM_THREAD',
     a dedicated thread that handles alarms is created. This is only
     used on some systems where there are problems with `sigwait()' or
     if you want to use the `thr_alarm()' code in your application
     without a dedicated signal handling thread.

   * If the server is started with the `--flush_time=VAL' option, a
     dedicated thread is created to flush all tables every VAL seconds.

   * Each table for which *Note `INSERT DELAYED': insert-delayed.
     statements are issued gets its own thread.  See *Note
     insert-delayed::.

*Note `mysqladmin processlist': mysqladmin. only shows the connection,
*Note `INSERT DELAYED': insert-delayed, and replication threads.


File: manual.info,  Node: mysql-test-suite,  Prev: mysql-threads,  Up: mysql-internals

21.1.2 The MySQL Test Suite
---------------------------

The test system that is included in Unix source and binary
distributions makes it possible for users and developers to perform
regression tests on the MySQL code. These tests can be run on Unix.

You can also write your own test cases. For information about the MySQL
Test Framework, including system requirements, see the manual available
at `http://dev.mysql.com/doc/'.

The current set of test cases doesn't test everything in MySQL, but it
should catch most obvious bugs in the SQL processing code, operating
system or library issues, and is quite thorough in testing replication.
Our goal is to have the tests cover 100% of the code. We welcome
contributions to our test suite. You may especially want to contribute
tests that examine the functionality critical to your system because
this ensures that all future MySQL releases work well with your
applications.

The test system consists of a test language interpreter (`mysqltest'),
a Perl script to run all tests (`mysql-test-run.pl'), the actual test
cases written in a special test language, and their expected results.
To run the test suite on your system after a build, type `make test'
from the source root directory, or change location to the `mysql-test'
directory and type `./mysql-test-run.pl'. If you have installed a
binary distribution, change location to the `mysql-test' directory
under the installation root directory (for example,
`/usr/local/mysql/mysql-test'), and run `./mysql-test-run.pl'. All
tests should succeed. If any do not, feel free to try to find out why
and report the problem if it indicates a bug in MySQL. See *Note
bug-reports::.

If one test fails, you should run `mysql-test-run.pl' with the
`--force' option to check whether any other tests fail.

If you have a copy of *Note `mysqld': mysqld. running on the machine
where you want to run the test suite, you do not have to stop it, as
long as it is not using ports `9306' or `9307'. If either of those
ports is taken, you should set the `MTR_BUILD_THREAD' environment
variable to an appropriate value, and the test suite will use a
different set of ports for master, slave, NDB, and Instance Manager).
For example:

     shell> export MTR_BUILD_THREAD=31
     shell> ./mysql-test-run.pl [OPTIONS] [TEST_NAME]

In the `mysql-test' directory, you can run an individual test case with
`./mysql-test-run.pl TEST_NAME'.

If you have a question about the test suite, or have a test case to
contribute, send an email message to the MySQL `internals' mailing
list. See *Note mailing-lists::. This list does not accept attachments,
so you should FTP all the relevant files to:
`ftp://ftp.mysql.com/pub/mysql/upload/'


File: manual.info,  Node: adding-functions,  Next: adding-procedures,  Prev: mysql-internals,  Up: extending-mysql

21.2 Adding New Functions to MySQL
==================================

* Menu:

* udf-features::                 Features of the User-Defined Function Interface
* adding-udf::                   Adding a New User-Defined Function
* adding-native-function::       Adding a New Native Function

There are three ways to add new functions to MySQL:

   * You can add functions through the user-defined function (UDF)
     interface. User-defined functions are compiled as object files and
     then added to and removed from the server dynamically using the
     *Note `CREATE FUNCTION': create-function. and *Note `DROP
     FUNCTION': drop-function. statements. See *Note
     create-function-udf::.

   * You can add functions as native (built-in) MySQL functions.
     Native functions are compiled into the *Note `mysqld': mysqld.
     server and become available on a permanent basis.

   * Another way to add functions is by creating stored functions.
     These are written using SQL statements rather than by compiling
     object code. The syntax for writing stored functions is not
     covered here. See *Note stored-routines::.

Each method of creating compiled functions has advantages and
disadvantages:

   * If you write user-defined functions, you must install object files
     in addition to the server itself. If you compile your function
     into the server, you don't need to do that.

   * Native functions require you to modify a source distribution.
     UDFs do not. You can add UDFs to a binary MySQL distribution.  No
     access to MySQL source is necessary.

   * If you upgrade your MySQL distribution, you can continue to use
     your previously installed UDFs, unless you upgrade to a newer
     version for which the UDF interface changes. For native functions,
     you must repeat your modifications each time you upgrade.

Whichever method you use to add new functions, they can be invoked in
SQL statements just like native functions such as `ABS()' or
`SOUNDEX()'.

See *Note function-resolution::, for the rules describing how the
server interprets references to different kinds of functions.

The following sections describe features of the UDF interface, provide
instructions for writing UDFs, discuss security precautions that MySQL
takes to prevent UDF misuse, and describe how to add native MySQL
functions.

For example source code that illustrates how to write UDFs, take a look
at the `sql/udf_example.c' file that is provided in MySQL source
distributions.


File: manual.info,  Node: udf-features,  Next: adding-udf,  Prev: adding-functions,  Up: adding-functions

21.2.1 Features of the User-Defined Function Interface
------------------------------------------------------

The MySQL interface for user-defined functions provides the following
features and capabilities:

   * Functions can return string, integer, or real values and can
     accept arguments of those same types.

   * You can define simple functions that operate on a single row at a
     time, or aggregate functions that operate on groups of rows.

   * Information is provided to functions that enables them to check
     the number, types, and names of the arguments passed to them.

   * You can tell MySQL to coerce arguments to a given type before
     passing them to a function.

   * You can indicate that a function returns `NULL' or that an error
     occurred.


File: manual.info,  Node: adding-udf,  Next: adding-native-function,  Prev: udf-features,  Up: adding-functions

21.2.2 Adding a New User-Defined Function
-----------------------------------------

* Menu:

* udf-calling::                  UDF Calling Sequences for Simple Functions
* udf-aggr-calling::             UDF Calling Sequences for Aggregate Functions
* udf-arguments::                UDF Argument Processing
* udf-return-values::            UDF Return Values and Error Handling
* udf-compiling::                Compiling and Installing User-Defined Functions
* udf-security::                 User-Defined Function Security Precautions

For the UDF mechanism to work, functions must be written in C or C++
(or another language that can use C calling conventions), and your
operating system must support dynamic loading. The MySQL source
distribution includes a file `sql/udf_example.c' that defines 5 new
functions. Consult this file to see how UDF calling conventions work.
UDF-related symbols and data structures are defined in the
`include/mysql_com.h' header file. (You need not include this header
file directly because it is included by `mysql.h'.)

A UDF contains code that becomes part of the running server, so when
you write a UDF, you are bound by any and all constraints that
otherwise apply to writing server code. For example, you may have
problems if you attempt to use functions from the `libstdc++' library.
Note that these constraints may change in future versions of the
server, so it is possible that server upgrades will require revisions
to UDFs that were originally written for older servers. For information
about these constraints, see *Note source-configuration-options::, and
*Note compilation-problems::.

To be able to use UDFs, you need to link *Note `mysqld': mysqld.
dynamically. Don't configure MySQL using
`--with-mysqld-ldflags=-all-static'. If you want to use a UDF that
needs to access symbols from *Note `mysqld': mysqld. (for example, the
`metaphone' function in `sql/udf_example.c' that uses
`default_charset_info'), you must link the program with `-rdynamic'
(see `man dlopen'). If you plan to use UDFs, the rule of thumb is to
configure MySQL with `--with-mysqld-ldflags=-rdynamic' unless you have
a very good reason not to.

For each function that you want to use in SQL statements, you should
define corresponding C (or C++) functions. In the following discussion,
the name `xxx' is used for an example function name. To distinguish
between SQL and C/C++ usage, `XXX()' (uppercase) indicates an SQL
function call, and `xxx()' (lowercase) indicates a C/C++ function call.

*Note*:

When using C++ you can encapsulate your C functions within:

     extern "C" { ... }

This will ensure that your C++ function names remain readable in the
completed UDF.

The C/C++ functions that you write to implement the interface for
`XXX()' are:

   * `xxx()' (required)

     The main function. This is where the function result is computed.
     The correspondence between the SQL function data type and the
     return type of your C/C++ function is shown here.

     SQL Type          C/C++ Type
     `STRING'          `char *'
     *Note `INTEGER':  `long long'
     numeric-types.    
     *Note `REAL':     `double'
     numeric-types.    

     It is also possible to declare a *Note `DECIMAL': numeric-types.
     function, but currently the value is returned as a string, so you
     should write the UDF as though it were a `STRING' function. `ROW'
     functions are not implemented.

   * `xxx_init()' (optional)

     The initialization function for `xxx()'. It can be used for the
     following purposes:

        * To check the number of arguments to `XXX()'.

        * To check that the arguments are of a required type or,
          alternatively, to tell MySQL to coerce arguments to the types
          you want when the main function is called.

        * To allocate any memory required by the main function.

        * To specify the maximum length of the result.

        * To specify (for *Note `REAL': numeric-types.  functions) the
          maximum number of decimal places in the result.

        * To specify whether the result can be `NULL'.

   * `xxx_deinit()' (optional)

     The deinitialization function for `xxx()'.  It should deallocate
     any memory allocated by the initialization function.

When an SQL statement invokes `XXX()', MySQL calls the initialization
function `xxx_init()' to let it perform any required setup, such as
argument checking or memory allocation. If `xxx_init()' returns an
error, MySQL aborts the SQL statement with an error message and does
not call the main or deinitialization functions.  Otherwise, MySQL
calls the main function `xxx()' once for each row. After all rows have
been processed, MySQL calls the deinitialization function
`xxx_deinit()' so that it can perform any required cleanup.

For aggregate functions that work like `SUM()', you must also provide
the following functions:

   * `xxx_clear()'

     Reset the current aggregate value but do not insert the argument
     as the initial aggregate value for a new group.

   * `xxx_add()'

     Add the argument to the current aggregate value.

MySQL handles aggregate UDFs as follows:

  1. Call `xxx_init()' to let the aggregate function allocate any
     memory it needs for storing results.

  2. Sort the table according to the `GROUP BY' expression.

  3. Call `xxx_clear()' for the first row in each new group.

  4. Call `xxx_add()' for each row that belongs in the same group.

  5. Call `xxx()' to get the result for the aggregate when the group
     changes or after the last row has been processed.

  6. Repeat steps 3 to 5 until all rows has been processed

  7. Call `xxx_deinit()' to let the UDF free any memory it has
     allocated.

All functions must be thread-safe. This includes not just the main
function, but the initialization and deinitialization functions as
well, and also the additional functions required by aggregate
functions. A consequence of this requirement is that you are not
permitted to allocate any global or static variables that change! If
you need memory, you should allocate it in `xxx_init()' and free it in
`xxx_deinit()'.


File: manual.info,  Node: udf-calling,  Next: udf-aggr-calling,  Prev: adding-udf,  Up: adding-udf

21.2.2.1 UDF Calling Sequences for Simple Functions
...................................................

This section describes the different functions that you need to define
when you create a simple UDF.  *Note adding-udf::, describes the order
in which MySQL calls these functions.

The main `xxx()' function should be declared as shown in this section.
Note that the return type and parameters differ, depending on whether
you declare the SQL function `XXX()' to return `STRING', *Note
`INTEGER': numeric-types, or *Note `REAL': numeric-types. in the *Note
`CREATE FUNCTION': create-function. statement:

For `STRING' functions:

     char *xxx(UDF_INIT *initid, UDF_ARGS *args,
               char *result, unsigned long *length,
               char *is_null, char *error);

For *Note `INTEGER': numeric-types. functions:

     long long xxx(UDF_INIT *initid, UDF_ARGS *args,
                   char *is_null, char *error);

For *Note `REAL': numeric-types. functions:

     double xxx(UDF_INIT *initid, UDF_ARGS *args,
                   char *is_null, char *error);

*Note `DECIMAL': numeric-types. functions return string values and
should be declared the same way as `STRING' functions. `ROW' functions
are not implemented.

The initialization and deinitialization functions are declared like
this:

     my_bool xxx_init(UDF_INIT *initid, UDF_ARGS *args, char *message);

     void xxx_deinit(UDF_INIT *initid);

The `initid' parameter is passed to all three functions. It points to a
`UDF_INIT' structure that is used to communicate information between
functions. The `UDF_INIT' structure members follow. The initialization
function should fill in any members that it wishes to change. (To use
the default for a member, leave it unchanged.)

   * `my_bool maybe_null'

     `xxx_init()' should set `maybe_null' to `1' if `xxx()' can return
     `NULL'. The default value is `1' if any of the arguments are
     declared `maybe_null'.

   * `unsigned int decimals'

     The number of decimal digits to the right of the decimal point.
     The default value is the maximum number of decimal digits in the
     arguments passed to the main function. For example, if the
     function is passed `1.34', `1.345', and `1.3', the default would
     be 3, because `1.345' has 3 decimal digits.

     For arguments that have no fixed number of decimals, the
     `decimals' value is set to 31, which is 1 more than the maximum
     number of decimals permitted for the *Note `DECIMAL':
     numeric-types, *Note `FLOAT': numeric-types, and *Note `DOUBLE':
     numeric-types. data types.

     A `decimals' value of 31 is used for arguments in cases such as a
     *Note `FLOAT': numeric-types. or *Note `DOUBLE': numeric-types.
     column declared without an explicit number of decimals (for
     example, *Note `FLOAT': numeric-types. rather than `FLOAT(10,3)')
     and for floating-point constants such as `1345E-3'. It is also
     used for string and other nonnumber arguments that might be
     converted within the function to numeric form.

     The value to which the `decimals' member is initialized is only a
     default. It can be changed within the function to reflect the
     actual calculation performed.  The default is determined such that
     the largest number of decimals of the arguments is used. If the
     number of decimals is 31 for even one of the arguments, that is the
     value used for `decimals'.

   * `unsigned int max_length'

     The maximum length of the result. The default `max_length' value
     differs depending on the result type of the function. For string
     functions, the default is the length of the longest argument. For
     integer functions, the default is 21 digits. For real functions,
     the default is 13 plus the number of decimal digits indicated by
     `initid->decimals'. (For numeric functions, the length includes
     any sign or decimal point characters.)

     If you want to return a blob value, you can set `max_length' to
     65KB or 16MB. This memory is not allocated, but the value is used
     to decide which data type to use if there is a need to temporarily
     store the data.

   * `char *ptr'

     A pointer that the function can use for its own purposes.  For
     example, functions can use `initid->ptr' to communicate allocated
     memory among themselves. `xxx_init()' should allocate the memory
     and assign it to this pointer:

          initid->ptr = allocated_memory;

     In `xxx()' and `xxx_deinit()', refer to `initid->ptr' to use or
     deallocate the memory.

   * `my_bool const_item'

     `xxx_init()' should set `const_item' to `1' if `xxx()' always
     returns the same value and to `0' otherwise.


File: manual.info,  Node: udf-aggr-calling,  Next: udf-arguments,  Prev: udf-calling,  Up: adding-udf

21.2.2.2 UDF Calling Sequences for Aggregate Functions
......................................................

This section describes the different functions that you need to define
when you create an aggregate UDF.  *Note adding-udf::, describes the
order in which MySQL calls these functions.

   * `xxx_reset()'

     This function is called when MySQL finds the first row in a new
     group. It should reset any internal summary variables and then use
     the given `UDF_ARGS' argument as the first value in your internal
     summary value for the group. Declare `xxx_reset()' as follows:

          void xxx_reset(UDF_INIT *initid, UDF_ARGS *args,
                         char *is_null, char *error);

     `xxx_reset()' is not needed or used in MySQL 5.0, in which the UDF
     interface uses `xxx_clear()' instead. However, you can define both
     `xxx_reset()' and `xxx_clear()' if you want to have your UDF work
     with older versions of the server. (If you do include both
     functions, the `xxx_reset()' function in many cases can be
     implemented internally by calling `xxx_clear()' to reset all
     variables, and then calling `xxx_add()' to add the `UDF_ARGS'
     argument as the first value in the group.)

   * `xxx_clear()'

     This function is called when MySQL needs to reset the summary
     results. It is called at the beginning for each new group but can
     also be called to reset the values for a query where there were no
     matching rows. Declare `xxx_clear()' as follows:

          void xxx_clear(UDF_INIT *initid, char *is_null, char *error);

     `is_null' is set to point to `CHAR(0)' before calling
     `xxx_clear()'.

     If something went wrong, you can store a value in the variable to
     which the `error' argument points. `error' points to a single-byte
     variable, not to a string buffer.

     `xxx_clear()' is required by MySQL 5.0.

   * `xxx_add()'

     This function is called for all rows that belong to the same
     group. You should use it to add the value in the `UDF_ARGS'
     argument to your internal summary variable.

          void xxx_add(UDF_INIT *initid, UDF_ARGS *args,
                       char *is_null, char *error);

The `xxx()' function for an aggregate UDF should be declared the same
way as for a nonaggregate UDF. See *Note udf-calling::.

For an aggregate UDF, MySQL calls the `xxx()' function after all rows
in the group have been processed. You should normally never access its
`UDF_ARGS' argument here but instead return a value based on your
internal summary variables.

Return value handling in `xxx()' should be done the same way as for a
nonaggregate UDF. See *Note udf-return-values::.

The `xxx_reset()' and `xxx_add()' functions handle their `UDF_ARGS'
argument the same way as functions for nonaggregate UDFs. See *Note
udf-arguments::.

The pointer arguments to `is_null' and `error' are the same for all
calls to `xxx_reset()', `xxx_clear()', `xxx_add()' and `xxx()'. You can
use this to remember that you got an error or whether the `xxx()'
function should return `NULL'. You should not store a string into
`*error'!  `error' points to a single-byte variable, not to a string
buffer.

`*is_null' is reset for each group (before calling `xxx_clear()').
`*error' is never reset.

If `*is_null' or `*error' are set when `xxx()' returns, MySQL returns
`NULL' as the result for the group function.


File: manual.info,  Node: udf-arguments,  Next: udf-return-values,  Prev: udf-aggr-calling,  Up: adding-udf

21.2.2.3 UDF Argument Processing
................................

The `args' parameter points to a `UDF_ARGS' structure that has the
members listed here:

   * `unsigned int arg_count'

     The number of arguments. Check this value in the initialization
     function if you require your function to be called with a
     particular number of arguments. For example:

          if (args->arg_count != 2)
          {
              strcpy(message,"XXX() requires two arguments");
              return 1;
          }

     For other `UDF_ARGS' member values that are arrays, array
     references are zero-based. That is, refer to array members using
     index values from 0 to `args->arg_count' - 1.

   * `enum Item_result *arg_type'

     A pointer to an array containing the types for each argument. The
     possible type values are `STRING_RESULT', `INT_RESULT',
     `REAL_RESULT', and `DECIMAL_RESULT'.

     To make sure that arguments are of a given type and return an
     error if they are not, check the `arg_type' array in the
     initialization function. For example:

          if (args->arg_type[0] != STRING_RESULT ||
              args->arg_type[1] != INT_RESULT)
          {
              strcpy(message,"XXX() requires a string and an integer");
              return 1;
          }

     Arguments of type `DECIMAL_RESULT' are passed as strings, so you
     should handle them the same way as `STRING_RESULT' values.

     As an alternative to requiring your function's arguments to be of
     particular types, you can use the initialization function to set
     the `arg_type' elements to the types you want. This causes MySQL
     to coerce arguments to those types for each call to `xxx()'. For
     example, to specify that the first two arguments should be coerced
     to string and integer, respectively, do this in `xxx_init()':

          args->arg_type[0] = STRING_RESULT;
          args->arg_type[1] = INT_RESULT;

     Exact-value decimal arguments such as `1.3' or *Note `DECIMAL':
     numeric-types. column values are passed with a type of
     `DECIMAL_RESULT'.  However, the values are passed as strings. If
     you want to receive a number, use the initialization function to
     specify that the argument should be coerced to a `REAL_RESULT'
     value:

          args->arg_type[2] = REAL_RESULT;

     *Note*:

     Prior to MySQL 5.0.3, decimal arguments were passed as
     `REAL_RESULT' values. If you upgrade to a newer version and find
     that your UDF now receives string values, use the initialization
     function to coerce the arguments to numbers as just described.

   * `char **args'

     `args->args' communicates information to the initialization
     function about the general nature of the arguments passed to your
     function. For a constant argument `i', `args->args[i]' points to
     the argument value. (See below for instructions on how to access
     the value properly.) For a nonconstant argument, `args->args[i]' is
     `0'. A constant argument is an expression that uses only
     constants, such as `3' or `4*7-2' or `SIN(3.14)'. A nonconstant
     argument is an expression that refers to values that may change
     from row to row, such as column names or functions that are called
     with nonconstant arguments.

     For each invocation of the main function, `args->args' contains
     the actual arguments that are passed for the row currently being
     processed.

     If argument `i' represents `NULL', `args->args[i]' is a null
     pointer (0).  If the argument is not `NULL', functions can refer
     to it as follows:

        * An argument of type `STRING_RESULT' is given as a string
          pointer plus a length, to enable handling of binary data or
          data of arbitrary length.  The string contents are available
          as `args->args[i]' and the string length is
          `args->lengths[i]'. Do not assume that the string is
          null-terminated.

        * For an argument of type `INT_RESULT', you must cast
          `args->args[i]' to a `long long' value:

               long long int_val;
               int_val = *((long long*) args->args[i]);

        * For an argument of type `REAL_RESULT', you must cast
          `args->args[i]' to a `double' value:

               double    real_val;
               real_val = *((double*) args->args[i]);

        * For an argument of type `DECIMAL_RESULT', the value is passed
          as a string and should be handled like a `STRING_RESULT'
          value.

        * `ROW_RESULT' arguments are not implemented.

   * `unsigned long *lengths'

     For the initialization function, the `lengths' array indicates the
     maximum string length for each argument. You should not change
     these. For each invocation of the main function, `lengths'
     contains the actual lengths of any string arguments that are
     passed for the row currently being processed. For arguments of
     types `INT_RESULT' or `REAL_RESULT', `lengths' still contains the
     maximum length of the argument (as for the initialization
     function).

   * `char *maybe_null'

     For the initialization function, the `maybe_null' array indicates
     for each argument whether the argument value might be null (0 if
     no, 1 if yes).

   * `char **attributes'

     `args->attributes' communicates information about the names of the
     UDF arguments. For argument `i', the attribute name is available
     as a string in `args->attributes[i]' and the attribute length is
     `args->attribute_lengths[i]'. Do not assume that the string is
     null-terminated.

     By default, the name of a UDF argument is the text of the
     expression used to specify the argument. For UDFs, an argument may
     also have an optional `[AS] ALIAS_NAME' clause, in which case the
     argument name is ALIAS_NAME. The `attributes' value for each
     argument thus depends on whether an alias was given.

     Suppose that a UDF `my_udf()' is invoked as follows:

          SELECT my_udf(expr1, expr2 AS alias1, expr3 alias2);

     In this case, the `attributes' and `attribute_lengths' arrays will
     have these values:

          args->attributes[0] = "expr1"
          args->attribute_lengths[0] = 5

          args->attributes[1] = "alias1"
          args->attribute_lengths[1] = 6

          args->attributes[2] = "alias2"
          args->attribute_lengths[2] = 6

   * `unsigned long *attribute_lengths'

     The `attribute_lengths' array indicates the length of each
     argument name.


File: manual.info,  Node: udf-return-values,  Next: udf-compiling,  Prev: udf-arguments,  Up: adding-udf

21.2.2.4 UDF Return Values and Error Handling
.............................................

The initialization function should return `0' if no error occurred and
`1' otherwise. If an error occurs, `xxx_init()' should store a
null-terminated error message in the `message' parameter. The message
is returned to the client. The message buffer is `MYSQL_ERRMSG_SIZE'
characters long, but you should try to keep the message to less than 80
characters so that it fits the width of a standard terminal screen.

The return value of the main function `xxx()' is the function value,
for `long long' and `double' functions. A string function should return
a pointer to the result and set `*length' to the length (in bytes) of
the return value. For example:

     memcpy(result, "result string", 13);
     *length = 13;

MySQL passes a buffer to the `xxx()' function using the `result'
parameter. This buffer is sufficiently long to hold 255 characters,
which can be multi-byte characters. The `xxx()' function can store the
result in this buffer if it fits, in which case the return value should
be a pointer to the buffer. If the function stores the result in a
different buffer, it should return a pointer to that buffer.

If your string function does not use the supplied buffer (for example,
if it needs to return a string longer than 255 characters), you must
allocate the space for your own buffer with `malloc()' in your
`xxx_init()' function or your `xxx()' function and free it in your
`xxx_deinit()' function. You can store the allocated memory in the
`ptr' slot in the `UDF_INIT' structure for reuse by future `xxx()'
calls. See *Note udf-calling::.

To indicate a return value of `NULL' in the main function, set
`*is_null' to `1':

     *is_null = 1;

To indicate an error return in the main function, set `*error' to `1':

     *error = 1;

If `xxx()' sets `*error' to `1' for any row, the function value is
`NULL' for the current row and for any subsequent rows processed by the
statement in which `XXX()' was invoked.  (`xxx()' is not even called
for subsequent rows.)


File: manual.info,  Node: udf-compiling,  Next: udf-security,  Prev: udf-return-values,  Up: adding-udf

21.2.2.5 Compiling and Installing User-Defined Functions
........................................................

Files implementing UDFs must be compiled and installed on the host
where the server runs. This process is described below for the example
UDF file `sql/udf_example.c' that is included in the MySQL source
distribution.

If a UDF will be referred to in statements that will be replicated to
slave servers, you must ensure that every slave also has the function
available. Otherwise, replication will fail on the slaves when they
attempt to invoke the function.

The immediately following instructions are for Unix.  Instructions for
Windows are given later in this section.

The `udf_example.c' file contains the following functions:

   * `metaphon()' returns a metaphon string of the string argument.
     This is something like a soundex string, but it is more tuned for
     English.

   * `myfunc_double()' returns the sum of the ASCII values of the
     characters in its arguments, divided by the sum of the length of
     its arguments.

   * `myfunc_int()' returns the sum of the length of its arguments.

   * `sequence([const int])' returns a sequence starting from the given
     number or 1 if no number has been given.

   * `lookup()' returns the IP address for a host name.

   * `reverse_lookup()' returns the host name for an IP address. The
     function may be called either with a single string argument of the
     form `'xxx.xxx.xxx.xxx'' or with four numbers.

   * `avgcost()' returns an average cost. This is an aggregate function.

A dynamically loadable file should be compiled as a sharable object
file, using a command something like this:

     shell> gcc -shared -o udf_example.so udf_example.c

If you are using `gcc' with `configure' and `libtool' (which is how
MySQL is configured), you should be able to create `udf_example.so'
with a simpler command:

     shell> make udf_example.la

After you compile a shared object containing UDFs, you must install it
and tell MySQL about it. Compiling a shared object from `udf_example.c'
using `gcc' directly produces a file named `udf_example.so'. Compiling
the shared object using `make' produces a file named something like
`udf_example.so.0.0.0' in the `.libs' directory (the exact name may
vary from platform to platform).

As of MySQL 5.0.67, copy the shared object to server's plugin directory
and name it `udf_example.so'.  This directory is given by the value of
the `plugin_dir' system variable.

Prior to MySQL 5.0.67, or if the value of `plugin_dir' is empty, the
shared object should be placed in a directory such as `/usr/lib' that
is searched by your system's dynamic (runtime) linker, or you can add
the directory in which you place the shared object to the linker
configuration file (for example, `/etc/ld.so.conf').

On many systems, you can also set the `LD_LIBRARY' or `LD_LIBRARY_PATH'
environment variable to point at the directory where you have the files
for your UDF.  You should set the variable in *Note `mysql.server':
mysql-server.  or *Note `mysqld_safe': mysqld-safe. startup scripts and
restart *Note `mysqld': mysqld. You might do this if you want to place
the object file in a directory accessible only to the server and not in
a public directory. The `dlopen' manual page tells you which variable
to use on your system.

The dynamic linker name is system-specific (for example, `ld-elf.so.1'
on FreeBSD, `ld.so' on Linux, or `dyld' on Mac OS X). Consult your
system documentation for information about the linker name and how to
configure it.

On some systems, the `ldconfig' program that configures the dynamic
linker does not recognize a shared object unless its name begins with
`lib'. In this case you should rename a file such as `udf_example.so' to
`libudf_example.so'.

On Windows, you can compile user-defined functions by using the
following procedure:

  1. Obtain the development source for MySQL 5.0.  See *Note
     getting-mysql::.

  2. Obtain the `CMake' build utility, if necessary, from
     `http://www.cmake.org'.  (Version 2.6 or later is required).

  3. In the source tree, look in the `sql' directory. There are files
     named `udf_example.def' `udf_example.c' there. Copy both files
     from this directory to your working directory.

  4. Create a `CMake' `makefile' (`CMakeLists.txt') with these contents:

          PROJECT(udf_example)

          # Path for MySQL include directory
          INCLUDE_DIRECTORIES("c:/mysql/include")

          ADD_DEFINITIONS("-DHAVE_DLOPEN")
          ADD_LIBRARY(udf_example MODULE udf_example.c udf_example.def)
          TARGET_LINK_LIBRARIES(udf_example wsock32)

  5. Create the VC project and solution files:

          cmake -G "<Generator>"

     Invoking `cmake --help' shows you a list of valid Generators.

  6. Create `udf_example.dll':

          devenv udf_example.sln /build Release

After the shared object file has been installed, notify *Note `mysqld':
mysqld. about the new functions with the following statements. If
object files have a suffix different from `.so' on your system,
substitute the correct suffix throughout (for example, `.dll' on
Windows).

     mysql> CREATE FUNCTION metaphon RETURNS STRING SONAME 'udf_example.so';
     mysql> CREATE FUNCTION myfunc_double RETURNS REAL SONAME 'udf_example.so';
     mysql> CREATE FUNCTION myfunc_int RETURNS INTEGER SONAME 'udf_example.so';
     mysql> CREATE FUNCTION sequence RETURNS INTEGER SONAME 'udf_example.so';
     mysql> CREATE FUNCTION lookup RETURNS STRING SONAME 'udf_example.so';
     mysql> CREATE FUNCTION reverse_lookup
         ->        RETURNS STRING SONAME 'udf_example.so';
     mysql> CREATE AGGREGATE FUNCTION avgcost
         ->        RETURNS REAL SONAME 'udf_example.so';

To delete functions, use *Note `DROP FUNCTION': drop-function.:

     mysql> DROP FUNCTION metaphon;
     mysql> DROP FUNCTION myfunc_double;
     mysql> DROP FUNCTION myfunc_int;
     mysql> DROP FUNCTION sequence;
     mysql> DROP FUNCTION lookup;
     mysql> DROP FUNCTION reverse_lookup;
     mysql> DROP FUNCTION avgcost;

The *Note `CREATE FUNCTION': create-function. and *Note `DROP
FUNCTION': drop-function. statements update the `func' system table in
the `mysql' database. The function's name, type and shared library name
are saved in the table. You must have the `INSERT' or `DELETE'
privilege for the `mysql' database to create or drop functions,
respectively.

You should not use *Note `CREATE FUNCTION': create-function. to add a
function that has previously been created. If you need to reinstall a
function, you should remove it with *Note `DROP FUNCTION':
drop-function.  and then reinstall it with *Note `CREATE FUNCTION':
create-function. You would need to do this, for example, if you
recompile a new version of your function, so that *Note `mysqld':
mysqld. gets the new version. Otherwise, the server continues to use
the old version.

An active function is one that has been loaded with *Note `CREATE
FUNCTION': create-function. and not removed with *Note `DROP FUNCTION':
drop-function. All active functions are reloaded each time the server
starts, unless you start *Note `mysqld': mysqld. with the
`--skip-grant-tables' option. In this case, UDF initialization is
skipped and UDFs are unavailable.


File: manual.info,  Node: udf-security,  Prev: udf-compiling,  Up: adding-udf

21.2.2.6 User-Defined Function Security Precautions
...................................................

MySQL takes the following measures to prevent misuse of user-defined
functions.

You must have the `INSERT' privilege to be able to use *Note `CREATE
FUNCTION': create-function. and the `DELETE' privilege to be able to
use *Note `DROP FUNCTION': drop-function. This is necessary because
these statements add and delete rows from the `mysql.func' table.

UDFs should have at least one symbol defined in addition to the `xxx'
symbol that corresponds to the main `xxx()' function. These auxiliary
symbols correspond to the `xxx_init()', `xxx_deinit()', `xxx_reset()',
`xxx_clear()', and `xxx_add()' functions. As of MySQL 5.0.3, *Note
`mysqld': mysqld. supports an `--allow-suspicious-udfs' option that
controls whether UDFs that have only an `xxx' symbol can be loaded. By
default, the option is off, to prevent attempts at loading functions
from shared object files other than those containing legitimate UDFs.
If you have older UDFs that contain only the `xxx' symbol and that
cannot be recompiled to include an auxiliary symbol, it may be
necessary to specify the `--allow-suspicious-udfs' option. Otherwise,
you should avoid enabling this capability.

UDF object files cannot be placed in arbitrary directories.  They must
be located in some system directory that the dynamic linker is
configured to search. To enforce this restriction and prevent attempts
at specifying path names outside of directories searched by the dynamic
linker, MySQL checks the shared object file name specified in *Note
`CREATE FUNCTION': create-function. statements for path name delimiter
characters. As of MySQL 5.0.3, MySQL also checks for path name
delimiters in file names stored in the `mysql.func' table when it loads
functions.  This prevents attempts at specifying illegitimate path names
through direct manipulation of the `mysql.func' table. For information
about UDFs and the runtime linker, see *Note udf-compiling::.


File: manual.info,  Node: adding-native-function,  Prev: adding-udf,  Up: adding-functions

21.2.3 Adding a New Native Function
-----------------------------------

To add a new native MySQL function, use the procedure described here,
which requires that you use a source distribution. You cannot add
native functions to a binary distribution because it is necessary to
modify MySQL source code and compile MySQL from the modified source. If
you migrate to another version of MySQL (for example, when a new
version is released), you must repeat the procedure with the new
version.

If the new native function will be referred to in statements that will
be replicated to slave servers, you must ensure that every slave server
also has the function available. Otherwise, replication will fail on
the slaves when they attempt to invoke the function.

To add a new native function, follow these steps to modify source files
in the `sql' directory:

  1. Add one line to `lex.h' that defines the function name in the
     `sql_functions[]' array.

  2. If the function prototype is simple (just takes zero, one, two, or
     three arguments), add a line to the `sql_functions[]' array in
     `lex.h' that specifies `SYM(FUNC_ARGN)' as the second argument
     (where N is the number of arguments the function takes). Also, add
     a function in `item_create.cc' that creates a function object.
     Look at `"ABS"' and `create_funcs_abs()' for an example of this.

     If the function prototype is not simple (for example, if it takes
     a variable number of arguments), you should make two changes to
     `sql_yacc.yy'. One is a line that indicates the preprocessor
     symbol that `yacc' should define; this should be added at the
     beginning of the file. The other is an `item' to be added to the
     `simple_expr' parsing rule that defines the function parameters.
     You will need an item for each syntax with which the function can
     be called. For an example that shows how this is done, check all
     occurrences of `ATAN' in `sql_yacc.yy'.

  3. In `item_func.h', declare a class inheriting from `Item_num_func'
     or `Item_str_func', depending on whether your function returns a
     number or a string.

  4. In `item_func.cc', add one of the following declarations,
     depending on whether you are defining a numeric or string function:

          double   Item_func_newname::val()
          longlong Item_func_newname::val_int()
          String  *Item_func_newname::Str(String *str)

     If you inherit your object from any of the standard items (like
     `Item_num_func'), you probably only have to define one of these
     functions and let the parent object take care of the other
     functions. For example, the `Item_str_func' class defines a
     `val()' function that executes `atof()' on the value returned by
     `::str()'.

  5. If the function is nondeterministic, include the following
     statement in the item constructor to indicate that function
     results should not be cached:

          current_thd->lex->safe_to_cache_query=0;

     A function is nondeterministic if, given fixed values for its
     arguments, it can return different results for different
     invocations.

  6. You should probably also define the following object function:

          void Item_func_newname::fix_length_and_dec()

     This function should at least calculate `max_length' based on the
     given arguments.  `max_length' is the maximum number of characters
     the function may return. This function should also set `maybe_null
     = 0' if the main function can't return a `NULL' value. The
     function can check whether any of the function arguments can
     return `NULL' by checking the arguments' `maybe_null' variable.
     Look at `Item_func_mod::fix_length_and_dec' for a typical example
     of how to do this.

All functions must be thread-safe. In other words, do not use any
global or static variables in the functions without protecting them
with mutexes.

If you want to return `NULL' from `::val()', `::val_int()', or
`::str()', you should set `null_value' to 1 and return 0.

For `::str()' object functions, there are additional considerations to
be aware of:

   * The `String *str' argument provides a string buffer that may be
     used to hold the result. (For more information about the `String'
     type, take a look at the `sql_string.h' file.)

   * The `::str()' function should return the string that holds the
     result, or `(char*) 0' if the result is `NULL'.

   * All current string functions try to avoid allocating any memory
     unless absolutely necessary!


File: manual.info,  Node: adding-procedures,  Next: porting,  Prev: adding-functions,  Up: extending-mysql

21.3 Adding New Procedures to MySQL
===================================

* Menu:

* procedure-analyse::            `PROCEDURE ANALYSE'
* writing-a-procedure::          Writing a Procedure

In MySQL, you can define a procedure in C++ that can access and modify
the data in a query before it is sent to the client. The modification
can be done on a row-by-row or `GROUP BY' level.

We have created an example procedure to show you what can be done.


File: manual.info,  Node: procedure-analyse,  Next: writing-a-procedure,  Prev: adding-procedures,  Up: adding-procedures

21.3.1 `PROCEDURE ANALYSE'
--------------------------

`ANALYSE([MAX_ELEMENTS[,MAX_MEMORY]])'

`ANALYSE()' is defined in the `sql/sql_analyse.cc' source file, which
serves as an example of how to create a procedure for use with the
`PROCEDURE' clause of *Note `SELECT': select. statements.  `ANALYSE()'
is built in and is available by default; other procedures can be
created using the format demonstrated in the source file.

`ANALYSE()' examines the result from a query and returns an analysis of
the results that suggests optimal data types for each column that may
help reduce table sizes. To obtain this analysis, append `PROCEDURE
ANALYSE' to the end of a *Note `SELECT': select. statement:

     SELECT ... FROM ... WHERE ... PROCEDURE ANALYSE([MAX_ELEMENTS,[MAX_MEMORY]])

For example:

     SELECT col1, col2 FROM table1 PROCEDURE ANALYSE(10, 2000);

The results show some statistics for the values returned by the query,
and propose an optimal data type for the columns. This can be helpful
for checking your existing tables, or after importing new data. You may
need to try different settings for the arguments so that `PROCEDURE
ANALYSE()' does not suggest the *Note `ENUM': enum. data type when it
is not appropriate.

The arguments are optional and are used as follows:

   * MAX_ELEMENTS (default 256) is the maximum number of distinct
     values that `ANALYSE()' notices per column. This is used by
     `ANALYSE()' to check whether the optimal data type should be of
     type *Note `ENUM': enum.; if there are more than MAX_ELEMENTS
     distinct values, then *Note `ENUM': enum. is not a suggested type.

   * MAX_MEMORY (default 8192) is the maximum amount of memory that
     `ANALYSE()' should allocate per column while trying to find all
     distinct values.


File: manual.info,  Node: writing-a-procedure,  Prev: procedure-analyse,  Up: adding-procedures

21.3.2 Writing a Procedure
--------------------------

You can find information about procedures by examining the following
source files:

   * `sql/sql_analyse.cc'

   * `sql/procedure.h'

   * `sql/procedure.cc'

   * `sql/sql_select.cc'

See also Writing a Procedure
(http://forge.mysql.com/wiki/MySQL_Internals_Procedure) at MySQL Forge.


File: manual.info,  Node: porting,  Prev: adding-procedures,  Up: extending-mysql

21.4 Debugging and Porting MySQL
================================

* Menu:

* debugging-server::             Debugging a MySQL Server
* debugging-client::             Debugging a MySQL Client
* the-dbug-package::             The DBUG Package

This appendix helps you port MySQL to other operating systems. Do check
the list of currently supported operating systems first. See *Note
supported-os::. If you have created a new port of MySQL, please let us
know so that we can list it here and on our Web site
(http://www.mysql.com/), recommending it to other users.

*Note*:

If you create a new port of MySQL, you are free to copy and distribute
it under the GPL license, but it does not make you a copyright holder
of MySQL.

A working POSIX thread library is needed for the server.

Both the server and the client need a working C++ compiler. We use
`gcc' on many platforms. Other compilers that are known to work are Sun
Studio, HP-UX `aCC', IBM AIX `xlC_r'), Intel `ecc/icc'.  With previous
versions on the respective platforms, we also used Irix `cc' and Compaq
`cxx'.

*Important*:

If you are trying to build MySQL 5.0 with `icc' on the IA64 platform,
and need support for MySQL Cluster, you should first ensure that you
are using `icc' version 9.1.043 or later. (For details, see Bug #21875.)

To compile only the client, use `./configure --without-server'.

If you want or need to change any `Makefile' or the `configure' script,
you also need GNU Automake and Autoconf. See *Note
installing-development-tree::.

All steps needed to remake everything from the most basic files.

     /bin/rm */.deps/*.P
     /bin/rm -f config.cache
     aclocal
     autoheader
     aclocal
     automake
     autoconf
     ./configure --with-debug=full --prefix='your installation directory'

     # The makefiles generated above need GNU make 3.75 or newer.
     # (called gmake below)
     gmake clean all install init-db

If you run into problems with a new port, you may have to do some
debugging of MySQL! See *Note debugging-server::.

*Note*:

Before you start debugging *Note `mysqld': mysqld, first get the test
programs `mysys/thr_alarm' and `mysys/thr_lock' to work. This ensures
that your thread installation has even a remote chance to work!


File: manual.info,  Node: debugging-server,  Next: debugging-client,  Prev: porting,  Up: porting

21.4.1 Debugging a MySQL Server
-------------------------------

* Menu:

* compiling-for-debugging::      Compiling MySQL for Debugging
* making-trace-files::           Creating Trace Files
* making-windows-dumps::         Using `pdb' to create a Windows crashdump
* using-gdb-on-mysqld::          Debugging `mysqld' under `gdb'
* using-stack-trace::            Using a Stack Trace
* using-log-files::              Using Server Logs to Find Causes of Errors in `mysqld'
* reproducible-test-case::       Making a Test Case If You Experience Table Corruption

If you are using some functionality that is very new in MySQL, you can
try to run *Note `mysqld': mysqld. with the `--skip-new' (which
disables all new, potentially unsafe functionality) or with
`--safe-mode' which disables a lot of optimization that may cause
problems. See *Note crashing::.

If *Note `mysqld': mysqld. doesn't want to start, you should verify
that you don't have any `my.cnf' files that interfere with your setup!
You can check your `my.cnf' arguments with *Note `mysqld
--print-defaults': mysqld. and avoid using them by starting with *Note
`mysqld --no-defaults ...': mysqld.

If *Note `mysqld': mysqld. starts to eat up CPU or memory or if it
`hangs,' you can use *Note `mysqladmin processlist status': mysqladmin.
to find out if someone is executing a query that takes a long time. It
may be a good idea to run *Note `mysqladmin -i10 processlist status':
mysqladmin. in some window if you are experiencing performance problems
or problems when new clients can't connect.

The command *Note `mysqladmin debug': mysqladmin. dumps some
information about locks in use, used memory and query usage to the
MySQL log file. This may help solve some problems. This command also
provides some useful information even if you haven't compiled MySQL for
debugging!

If the problem is that some tables are getting slower and slower you
should try to optimize the table with *Note `OPTIMIZE TABLE':
optimize-table. or *Note `myisamchk': myisamchk. See *Note
server-administration::. You should also check the slow queries with
*Note `EXPLAIN': explain.

You should also read the OS-specific section in this manual for
problems that may be unique to your environment. See *Note
operating-system-specific-notes::.


File: manual.info,  Node: compiling-for-debugging,  Next: making-trace-files,  Prev: debugging-server,  Up: debugging-server

21.4.1.1 Compiling MySQL for Debugging
......................................

If you have some very specific problem, you can always try to debug
MySQL. To do this you must configure MySQL with the `--with-debug' or
the `--with-debug=full' option.  You can check whether MySQL was
compiled with debugging by doing: *Note `mysqld --help': mysqld. If the
`--debug' flag is listed with the options then you have debugging
enabled. *Note `mysqladmin ver': mysqladmin. also lists the *Note
`mysqld': mysqld. version as *Note `mysql ... --debug': mysql. in this
case.

If you are using `gcc', the recommended `configure' line is:

     CC=gcc CFLAGS="-O2" CXX=gcc CXXFLAGS="-O2 -felide-constructors \
        -fno-exceptions -fno-rtti" ./configure --prefix=/usr/local/mysql \
        --with-debug --with-extra-charsets=complex

This avoids problems with the `libstdc++' library and with C++
exceptions (many compilers have problems with C++ exceptions in
threaded code) and compile a MySQL version with support for all
character sets.

If you suspect a memory overrun error, you can configure MySQL with
`--with-debug=full', which installs a memory allocation (`SAFEMALLOC')
checker. However, running with `SAFEMALLOC' is quite slow, so if you get
performance problems you should start *Note `mysqld': mysqld. with the
`--skip-safemalloc' option. This disables the memory overrun checks for
each call to `malloc()' and `free()'.

If *Note `mysqld': mysqld. stops crashing when you compile it with
`--with-debug', you probably have found a compiler bug or a timing bug
within MySQL. In this case, you can try to add `-g' to the `CFLAGS' and
`CXXFLAGS' variables above and not use `--with-debug'. If *Note
`mysqld': mysqld. dies, you can at least attach to it with `gdb' or use
`gdb' on the core file to find out what happened.

When you configure MySQL for debugging you automatically enable a lot
of extra safety check functions that monitor the health of *Note
`mysqld': mysqld. If they find something `unexpected,' an entry is
written to `stderr', which *Note `mysqld_safe': mysqld-safe. directs to
the error log! This also means that if you are having some unexpected
problems with MySQL and are using a source distribution, the first
thing you should do is to configure MySQL for debugging! (The second
thing is to send mail to a MySQL mailing list and ask for help. See
*Note mailing-lists::. If you believe that you have found a bug, please
use the instructions at *Note bug-reports::.

In the Windows MySQL distribution, `mysqld.exe' is by default compiled
with support for trace files. See also *Note making-trace-files::.


File: manual.info,  Node: making-trace-files,  Next: making-windows-dumps,  Prev: compiling-for-debugging,  Up: debugging-server

21.4.1.2 Creating Trace Files
.............................

If the *Note `mysqld': mysqld. server doesn't start or if you can cause
it to crash quickly, you can try to create a trace file to find the
problem.

To do this, you must have a *Note `mysqld': mysqld. that has been
compiled with debugging support. You can check this by executing
`mysqld -V'. If the version number ends with `-debug', it is compiled
with support for trace files. (On Windows, the debugging server is
named *Note `mysqld-debug': mysqld. rather than *Note `mysqld': mysqld.
as of MySQL 4.1.)

Start the *Note `mysqld': mysqld. server with a trace log in
`/tmp/mysqld.trace' on Unix or `C:\mysqld.trace' on Windows:

     shell> mysqld --debug

On Windows, you should also use the `--standalone' flag to not start
*Note `mysqld': mysqld. as a service. In a console window, use this
command:

     C:\> mysqld-debug --debug --standalone

After this, you can use the `mysql.exe' command-line tool in a second
console window to reproduce the problem. You can stop the *Note
`mysqld': mysqld. server with *Note `mysqladmin shutdown': mysqladmin.

The trace file can become *very large*! To generate a smaller trace
file, you can use debugging options something like this:

*Note `mysqld
--debug=d,info,error,query,general,where:O,/tmp/mysqld.trace': mysqld.

This only prints information with the most interesting tags to the
trace file.

If you make a bug report about this, please only send the lines from
the trace file to the appropriate mailing list where something seems to
go wrong! If you can't locate the wrong place, you can ftp the trace
file, together with a full bug report, to
`ftp://ftp.mysql.com/pub/mysql/upload/' so that a MySQL developer can
take a look at it.

The trace file is made with the *DBUG* package by Fred Fish.  See *Note
the-dbug-package::.


File: manual.info,  Node: making-windows-dumps,  Next: using-gdb-on-mysqld,  Prev: making-trace-files,  Up: debugging-server

21.4.1.3 Using `pdb' to create a Windows crashdump
..................................................

Starting with MySQL 5.0.24 the Program Database files (extension `pdb')
are included in the Noinstall distribution of MySQL. These files provide
information for debugging your MySQL installation in the event of a
problem.

The PDB file contains more detailed information about `mysqld' and
other tools that enables more detailed trace and dump files to be
created. You can use these with Dr Watson, `WinDbg' and Visual Studio to
debug *Note `mysqld': mysqld.

For more information on PDB files, see Microsoft Knowledge Base Article
121366 (http://support.microsoft.com/kb/121366/). For more information
on the debugging options available, see Debugging Tools for Windows
(http://www.microsoft.com/whdc/devtools/debugging/default.mspx).

Dr Watson is installed with all Windows distributions, but if you have
installed Windows development tools, Dr Watson may have been replaced
with WinDbg, the debugger included with Visual Studio, or the debugging
tools provided with Borland or Delphi.

To generate a crash file using Dr Watson, follow these steps:

  1. Start Dr Watson by running `drwtsn32.exe' interactively using the
     `-i' option:

          C:\> drwtsn32 -i

  2. Set the `Log File Path' to the directory where you want to store
     trace files.

  3. Make sure `Dump All Thread Contexts' and `Append To Existing Log
     File'.

  4. Uncheck `Dump Symbol Table', `Visual Notification', `Sound
     Notification' and `Create Crash Dump File'.

  5. Set the `Number of Instructions' to a suitable value to capture
     enough calls in the stacktrace.  A value of at 25 should be enough.

Note that the file generated can become very large.


File: manual.info,  Node: using-gdb-on-mysqld,  Next: using-stack-trace,  Prev: making-windows-dumps,  Up: debugging-server

21.4.1.4 Debugging `mysqld' under `gdb'
.......................................

On most systems you can also start *Note `mysqld': mysqld.  from `gdb'
to get more information if *Note `mysqld': mysqld. crashes.

With some older `gdb' versions on Linux you must use `run --one-thread'
if you want to be able to debug *Note `mysqld': mysqld. threads. In
this case, you can only have one thread active at a time. It is best to
upgrade to `gdb' 5.1 because thread debugging works much better with
this version!

NPTL threads (the new thread library on Linux) may cause problems while
running *Note `mysqld': mysqld. under `gdb'. Some symptoms are:

   * *Note `mysqld': mysqld. hangs during startup (before it writes
     `ready for connections').

   * *Note `mysqld': mysqld. crashes during a `pthread_mutex_lock()' or
     `pthread_mutex_unlock()' call.

In this case, you should set the following environment variable in the
shell before starting `gdb':

     LD_ASSUME_KERNEL=2.4.1
     export LD_ASSUME_KERNEL

When running *Note `mysqld': mysqld. under `gdb', you should disable
the stack trace with `--skip-stack-trace' to be able to catch segfaults
within `gdb'.

In MySQL 4.0.14 and above you should use the `--gdb' option to *Note
`mysqld': mysqld. This installs an interrupt handler for `SIGINT'
(needed to stop *Note `mysqld': mysqld. with `^C' to set breakpoints)
and disable stack tracing and core file handling.

It is very hard to debug MySQL under `gdb' if you do a lot of new
connections the whole time as `gdb' doesn't free the memory for old
threads. You can avoid this problem by starting *Note `mysqld': mysqld.
with `thread_cache_size' set to a value equal to `max_connections' + 1.
In most cases just using `--thread_cache_size=5'' helps a lot!

If you want to get a core dump on Linux if *Note `mysqld': mysqld. dies
with a SIGSEGV signal, you can start *Note `mysqld': mysqld. with the
`--core-file' option. This core file can be used to make a backtrace
that may help you find out why *Note `mysqld': mysqld. died:

     shell> gdb mysqld core
     gdb>   backtrace full
     gdb>   quit

See *Note crashing::.

If you are using `gdb' 4.17.x or above on Linux, you should install a
`.gdb' file, with the following information, in your current directory:

     set print sevenbit off
     handle SIGUSR1 nostop noprint
     handle SIGUSR2 nostop noprint
     handle SIGWAITING nostop noprint
     handle SIGLWP nostop noprint
     handle SIGPIPE nostop
     handle SIGALRM nostop
     handle SIGHUP nostop
     handle SIGTERM nostop noprint

If you have problems debugging threads with `gdb', you should download
gdb 5.x and try this instead. The new `gdb' version has very improved
thread handling!

Here is an example how to debug mysqld:

     shell> gdb /usr/local/libexec/mysqld
     gdb> run
     ...
     backtrace full # Do this when mysqld crashes

Include the above output in a bug report, which you can file using the
instructions in *Note bug-reports::.

If *Note `mysqld': mysqld. hangs you can try to use some system tools
like `strace' or `/usr/proc/bin/pstack' to examine where *Note
`mysqld': mysqld. has hung.

     strace /tmp/log libexec/mysqld

If you are using the Perl `DBI' interface, you can turn on debugging
information by using the `trace' method or by setting the `DBI_TRACE'
environment variable.


File: manual.info,  Node: using-stack-trace,  Next: using-log-files,  Prev: using-gdb-on-mysqld,  Up: debugging-server

21.4.1.5 Using a Stack Trace
............................

On some operating systems, the error log contains a stack trace if
*Note `mysqld': mysqld. dies unexpectedly. You can use this to find out
where (and maybe why) *Note `mysqld': mysqld. died. See *Note
error-log::. To get a stack trace, you must not compile *Note `mysqld':
mysqld. with the `-fomit-frame-pointer' option to gcc. See *Note
compiling-for-debugging::.

A stack trace in the error log looks something like this:

     mysqld got signal 11;
     Attempting backtrace. You can use the following information
     to find out where mysqld died. If you see no messages after
     this, something went terribly wrong...

     stack range sanity check, ok, backtrace follows
     0x40077552
     0x81281a0
     0x8128f47
     0x8127be0
     0x8127995
     0x8104947
     0x80ff28f
     0x810131b
     0x80ee4bc
     0x80c3c91
     0x80c6b43
     0x80c1fd9
     0x80c1686

You can use the *Note `resolve_stack_dump': resolve-stack-dump. utility
to determine where *Note `mysqld': mysqld. died by using the following
procedure:

  1. Copy the preceding numbers to a file, for example `mysqld.stack':

          0x9da402
          0x6648e9
          0x7f1a5af000f0
          0x7f1a5a10f0f2
          0x7412cb
          0x688354
          0x688494
          0x67a170
          0x67f0ad
          0x67fdf8
          0x6811b6
          0x66e05e

  2. Make a symbol file for the *Note `mysqld': mysqld.  server:

          shell> nm -n libexec/mysqld > /tmp/mysqld.sym

     If *Note `mysqld': mysqld. is not linked statically, use the
     following command instead:

          shell> nm -D -n libexec/mysqld > /tmp/mysqld.sym

     If you want to decode C++ symbols, use the `--demangle', if
     available, to `nm'. If your version of `nm' does not have this
     option, you will need to use the `c++filt' command after the stack
     dump has been produced to demangle the C++ names.

  3. Execute the following command:

          shell> resolve_stack_dump -s /tmp/mysqld.sym -n mysqld.stack

     If you were not able to include demangled C++ names in your symbol
     file, process the *Note `resolve_stack_dump': resolve-stack-dump.
     output using `c++filt':

          shell> resolve_stack_dump -s /tmp/mysqld.sym -n mysqld.stack | c++filt

     This prints out where *Note `mysqld': mysqld. died. If that does
     not help you find out why *Note `mysqld': mysqld. died, you should
     create a bug report and include the output from the preceding
     command with the bug report.

     However, in most cases it does not help us to have just a stack
     trace to find the reason for the problem. To be able to locate the
     bug or provide a workaround, in most cases we need to know the
     statement that killed *Note `mysqld': mysqld. and preferably a
     test case so that we can repeat the problem! See *Note
     bug-reports::.


File: manual.info,  Node: using-log-files,  Next: reproducible-test-case,  Prev: using-stack-trace,  Up: debugging-server

21.4.1.6 Using Server Logs to Find Causes of Errors in `mysqld'
...............................................................

Note that before starting *Note `mysqld': mysqld. with the general
query log enabled, you should check all your tables with *Note
`myisamchk': myisamchk. See *Note server-administration::.

If *Note `mysqld': mysqld. dies or hangs, you should start *Note
`mysqld': mysqld. with the general query log enabled.  See *Note
query-log::. When *Note `mysqld': mysqld. dies again, you can examine
the end of the log file for the query that killed *Note `mysqld':
mysqld.

If you use the default general query log file, the log is stored in the
database directory as `HOST_NAME.log' In most cases it is the last
query in the log file that killed *Note `mysqld': mysqld, but if
possible you should verify this by restarting *Note `mysqld': mysqld.
and executing the found query from the *Note `mysql': mysql.
command-line tools. If this works, you should also test all complicated
queries that didn't complete.

You can also try the command *Note `EXPLAIN': explain. on all *Note
`SELECT': select. statements that takes a long time to ensure that
*Note `mysqld': mysqld. is using indexes properly. See *Note explain::.

You can find the queries that take a long time to execute by starting
*Note `mysqld': mysqld. with the slow query log enabled. See *Note
slow-query-log::.

If you find the text `mysqld restarted' in the error log file (normally
named `hostname.err') you probably have found a query that causes *Note
`mysqld': mysqld. to fail. If this happens, you should check all your
tables with *Note `myisamchk': myisamchk. (see *Note
server-administration::), and test the queries in the MySQL log files
to see whether one fails. If you find such a query, try first upgrading
to the newest MySQL version.  If this doesn't help and you can't find
anything in the `mysql' mail archive, you should report the bug to a
MySQL mailing list. The mailing lists are described at
`http://lists.mysql.com/', which also has links to online list archives.

If you have started *Note `mysqld': mysqld. with `--myisam-recover',
MySQL automatically checks and tries to repair `MyISAM' tables if they
are marked as 'not closed properly' or 'crashed'. If this happens,
MySQL writes an entry in the `hostname.err' file `'Warning: Checking
table ...'' which is followed by `Warning: Repairing table' if the
table needs to be repaired. If you get a lot of these errors, without
*Note `mysqld': mysqld. having died unexpectedly just before, then
something is wrong and needs to be investigated further. See *Note
server-options::.

It is not a good sign if *Note `mysqld': mysqld. did die unexpectedly,
but in this case, you should not investigate the `Checking table...'
messages, but instead try to find out why *Note `mysqld': mysqld. died.


File: manual.info,  Node: reproducible-test-case,  Prev: using-log-files,  Up: debugging-server

21.4.1.7 Making a Test Case If You Experience Table Corruption
..............................................................

If you get corrupted tables or if *Note `mysqld': mysqld.  always fails
after some update commands, you can test whether this bug is
reproducible by doing the following:

   * Take down the MySQL daemon (with *Note `mysqladmin shutdown':
     mysqladmin.).

   * Make a backup of the tables (to guard against the very unlikely
     case that the repair does something bad).

   * Check all tables with *Note `myisamchk -s database/*.MYI':
     myisamchk. Repair any wrong tables with *Note `myisamchk -r
     database/TABLE.MYI': myisamchk.

   * Make a second backup of the tables.

   * Remove (or move away) any old log files from the MySQL data
     directory if you need more space.

   * Start *Note `mysqld': mysqld. with the binary log enabled. If you
     want to find a query that crashes *Note `mysqld': mysqld, you
     should start the server with both the general query log enabled as
     well. See *Note query-log::, and *Note binary-log::.

   * When you have gotten a crashed table, stop the `mysqld server'.

   * Restore the backup.

   * Restart the *Note `mysqld': mysqld. server *without* the binary log
     enabled.

   * Re-execute the commands with *Note `mysqlbinlog binary-log-file |
     mysql': mysqlbinlog. The binary log is saved in the MySQL database
     directory with the name `hostname-bin.NNNNNN'.

   * If the tables are corrupted again or you can get *Note `mysqld':
     mysqld. to die with the above command, you have found reproducible
     bug that should be easy to fix! FTP the tables and the binary log
     to `ftp://ftp.mysql.com/pub/mysql/upload/' and report it in our
     bugs database using the instructions given in *Note bug-reports::.
     (Please note that the `/pub/mysql/upload/' FTP directory is not
     listable, so you'll not see what you've uploaded in your FTP
     client.) If you are a support customer, you can use the MySQL
     Customer Support Center `https://support.mysql.com/' to alert the
     MySQL team about the problem and have it fixed as soon as possible.

You can also use the script *Note `mysql_find_rows': mysql-find-rows.
to just execute some of the update statements if you want to narrow
down the problem.

The preceding discussion applies only to RHEL4. The patch is
unnecessary for RHEL5.


File: manual.info,  Node: debugging-client,  Next: the-dbug-package,  Prev: debugging-server,  Up: porting

21.4.2 Debugging a MySQL Client
-------------------------------

To be able to debug a MySQL client with the integrated debug package,
you should configure MySQL with `--with-debug' or `--with-debug=full'.
See *Note source-configuration-options::.

Before running a client, you should set the `MYSQL_DEBUG' environment
variable:

     shell> MYSQL_DEBUG=d:t:O,/tmp/client.trace
     shell> export MYSQL_DEBUG

This causes clients to generate a trace file in `/tmp/client.trace'.

If you have problems with your own client code, you should attempt to
connect to the server and run your query using a client that is known
to work. Do this by running *Note `mysql': mysql. in debugging mode
(assuming that you have compiled MySQL with debugging on):

     shell> mysql --debug=d:t:O,/tmp/client.trace

This provides useful information in case you mail a bug report.  See
*Note bug-reports::.

If your client crashes at some 'legal' looking code, you should check
that your `mysql.h' include file matches your MySQL library file. A
very common mistake is to use an old `mysql.h' file from an old MySQL
installation with new MySQL library.


File: manual.info,  Node: the-dbug-package,  Prev: debugging-client,  Up: porting

21.4.3 The DBUG Package
-----------------------

The MySQL server and most MySQL clients are compiled with the DBUG
package originally created by Fred Fish. When you have configured MySQL
for debugging, this package makes it possible to get a trace file of
what the program is debugging. See *Note making-trace-files::.

This section summaries the argument values that you can specify in
debug options on the command line for MySQL programs that have been
built with debugging support. For more information about programming
with the DBUG package, see the DBUG manual in the `dbug' directory of
MySQL source distributions. It is best to use a recent distribution to
get the most updated DBUG manual.

You use the debug package by invoking a program with the
`--debug="..."' or the `-#...' option.

Most MySQL programs have a default debug string that is used if you
don't specify an option to `--debug'. The default trace file is usually
`/tmp/program_name.trace' on Unix and `\program_name.trace' on Windows.

The debug control string is a sequence of colon-separated fields as
follows:

     <field_1>:<field_2>:...:<field_N>

Each field consists of a mandatory flag character followed by an
optional ``,'' and comma-separated list of modifiers:

     flag[,modifier,modifier,...,modifier]

The following table shows the currently recognized flag characters.

Flag Description
`d'  Enable output from DBUG_<N> macros for the current state. May be
     followed by a list of keywords which selects output only for the
     DBUG macros with that keyword. An empty list of keywords implies
     output for all macros.
`D'  Delay after each debugger output line. The argument is the number of
     tenths of seconds to delay, subject to machine capabilities. For
     example, `-#D,20' specifies a delay of two seconds.
`f'  Limit debugging, tracing, and profiling to the list of named
     functions.  Note that a null list disables all functions. The
     appropriate `d' or `t' flags must still be given; this flag only
     limits their actions if they are enabled.
`F'  Identify the source file name for each line of debug or trace
     output.
`i'  Identify the process with the PID or thread ID for each line of
     debug or trace output.
`g'  Enable profiling. Create a file called `dbugmon.out' containing
     information that can be used to profile the program. May be
     followed by a list of keywords that select profiling only for the
     functions in that list. A null list implies that all functions are
     considered.
`L'  Identify the source file line number for each line of debug or trace
     output.
`n'  Print the current function nesting depth for each line of debug or
     trace output.
`N'  Number each line of debug output.
`o'  Redirect the debugger output stream to the specified file. The
     default output is `stderr'.
`O'  Like `o', but the file is really flushed between each write. When
     needed, the file is closed and reopened between each write.
`p'  Limit debugger actions to specified processes. A process must be
     identified with the `DBUG_PROCESS' macro and match one in the list
     for debugger actions to occur.
`P'  Print the current process name for each line of debug or trace
     output.
`r'  When pushing a new state, do not inherit the previous state's
     function nesting level. Useful when the output is to start at the
     left margin.
`S'  Do function `_sanity(_file_,_line_)' at each debugged function
     until `_sanity()' returns something that differs from 0. (Mostly
     used with `safemalloc' to find memory leaks)
`t'  Enable function call/exit trace lines. May be followed by a list
     (containing only one modifier) giving a numeric maximum trace
     level, beyond which no output occurs for either debugging or
     tracing macros. The default is a compile time option.

Some examples of debug control strings that might appear on a shell
command line (the `-#' is typically used to introduce a control string
to an application program) are:

     -#d:t
     -#d:f,main,subr1:F:L:t,20
     -#d,input,output,files:n
     -#d:t:i:O,\\mysqld.trace

In MySQL, common tags to print (with the `d' option) are `enter',
`exit', `error', `warning', `info', and `loop'.


File: manual.info,  Node: mysql-enterprise-monitor,  Next: mysql-enterprise-backup,  Prev: extending-mysql,  Up: Top

22 MySQL Enterprise Monitor
***************************

MySQL Enterprise Monitor is an enterprise monitoring system for MySQL
that keeps an eye on your MySQL servers, notifies you of potential
issues and problems, and advises you how to fix the issues. MySQL
Enterprise Monitor can monitor all kinds of configurations, from a
single MySQL server that is important to your business, all the way up
to a huge farm of MySQL servers powering a busy web site.

The following discussion briefly describes the basic components that
make up the MySQL Enterprise Monitor product. For more information, see
the MySQL Enterprise Monitor manual, available at
`http://dev.mysql.com/doc/mysql-monitor/en/'.

MySQL Enterprise Monitor components can be installed in various
configurations depending on your own database and network topology, to
give you the best combination of reliable and responsive monitoring
data, with minimal overhead on the database server machines. A typical
MySQL Enterprise Monitor installation consists of:

   * One or more MySQL servers that you want to monitor. MySQL
     Enterprise Monitor can monitor both Community and Enterprise MySQL
     server releases.

   * A MySQL Enterprise Monitor Agent for each monitored MySQL server.

   * A single MySQL Enterprise Service Manager, which collates
     information from the agents, and provides the user interface to
     the collected data.

MySQL Enterprise Monitor is designed to monitor one or more MySQL
servers. The monitoring information is collected by using an agent,
_MySQL Enterprise Monitor Agent_. The agent communicates with the MySQL
server that it monitors, collecting variables, status and health
information, and sending this information to the MySQL Enterprise
Service Manager. If you have multiple MySQL servers, then you have
multiple MySQL Enterprise Monitor Agent processes monitoring each MySQL
server.

The information collected by the agent about each MySQL server you are
monitoring is sent to the _MySQL Enterprise Service Manager_. This
server collates all of the information from the agents. As it collates
the information sent by the agents, the MySQL Enterprise Service
Manager continually tests the collected data, comparing the status of
the server to reasonable values. When thresholds are reached, the
server can trigger an event (including an alarm and notification) to
highlight a potential issue, such as low memory, high CPU usage, or
more complex conditions such insufficient buffer sizes and status
information. We call each test, with its associated threshold value, a
_rule_.

These rules, and the alarms and notifications, are each known as a
_MySQL Enterprise Advisor_. Advisors form a critical part of the MySQL
Enterprise Service Manager, as they provide warning information and
troubleshooting advice about potential problems.

The MySQL Enterprise Service Manager includes a web server, and you
interact with it through any web browser. This interface, the MySQL
Enterprise Dashboard, displays all of the information collected by the
agents, and lets you view all of your servers and their current status
as a group or individually. You control and configure all aspects of
the service using the MySQL Enterprise Dashboard.

The information supplied by the MySQL Enterprise Monitor Agent
processes also includes statistical and query information, which you
can view in the form of graphs. For example, you can view aspects such
as server load, query numbers, or index usage information as a graph
over time. The graph lets you pinpoint problems or potential issues on
your server, and can help diagnose the impact from database or external
problems (such as external system or network failure) by examining the
data from a specific time interval.

The MySQL Enterprise Monitor Agent can also be configured to collect
detailed information about the queries executed on your server,
including the row counts and performance times for executing each
query. You can correlate the detailed query data with the graphical
information to identify which queries were executing when you
experienced a particularly high load, index or other issue. The query
data is supported by a system called Query Analyzer, and the data can be
presented in different ways depending on your needs.


File: manual.info,  Node: mysql-enterprise-backup,  Next: licenses-third-party,  Prev: mysql-enterprise-monitor,  Up: Top

23 MySQL Enterprise Backup
**************************

The MySQL Enterprise Backup product performs hot backup
(http://dev.mysql.com/doc/refman/5.5/en/glossary.html#glos_hot_backup)
operations for MySQL databases. The product is architected for
efficient and reliable backups of tables created by the InnoDB storage
engine
(http://dev.mysql.com/doc/refman/5.5/en/glossary.html#glos_innodb). For
completeness, it can also back up tables from MyISAM and other storage
engines.

Hot backups
(http://dev.mysql.com/doc/refman/5.5/en/glossary.html#glos_hot_backup)
are performed while the database is running. This type of backup does
not block normal database operations, and it captures even changes that
occur while the backup is happening. For these reasons, hot backups are
desirable when your database `grows up' - when the data is large enough
that the backup takes significant time, and when your data is important
enough to your business so that you must capture every last change,
without taking your application, web site, or web service offline.

MySQL Enterprise Backup does a hot backup of all tables that use the
InnoDB storage engine. For tables using MyISAM or other non-InnoDB
storage engines, it does a `warm' backup, where the database continues
to run, but those tables cannot be modified while being backed up. For
efficient backup operations, you can designate InnoDB as the default
storage engine for new tables, or convert existing tables to use the
InnoDB storage engine.

For more information, see the MySQL Enterprise Backup manual, available
at `http://dev.mysql.com/doc/mysql-enterprise-backup/en/'.


File: manual.info,  Node: licenses-third-party,  Next: faqs,  Prev: mysql-enterprise-backup,  Up: Top

Appendix A Licenses for Third-Party Components
**********************************************

* Menu:

* license-ant-contrib::          Ant-Contrib License
* license-antlr-3-3::            ANTLR 3.3 License
* license-boost::                Boost Library License
* license-libedit::              Editline Library (`libedit') License
* license-dbug::                 Fred Fish's Dbug Library License
* license-glib-proxy::           GLib License (for MySQL Proxy)
* license-gnu-gpl-2-0::          GNU General Public License Version 2.0, June 1991
* license-gnu-lgpl-2-1::         GNU Lesser General Public License Version 2.1, February 1999
* license-gnu-libtool::          GNU Libtool License
* license-gnu-readline::         GNU Readline License
* license-lib-sql::              `lib_sql.cc' License
* license-libevent::             `libevent' License
* license-lpeg::                 `LPeg' Library License
* license-lua::                  Lua (liblua) License
* license-luafilesystem::        `LuaFileSystem' Library License
* license-pcre::                 PCRE License
* license-regex::                RegEX-Spencer Library License
* license-us-secure-hash::       RFC 3174 - US Secure Hash Algorithm 1 (SHA1) License
* license-libstring::            Richard A. O'Keefe String Library License
* license-slf4j::                Simple Logging Facade for Java (SLF4J) License
* license-zlib::                 `zlib' License
* license-zlib-net::             ZLIB.NET License

The following is a list of the libraries we have included with the
MySQL Server source and components used to test MySQL. We are thankful
to all individuals that have created these. Some of the components
require that their licensing terms be included in the documentation of
products that include them. Cross references to these licensing terms
are given with the applicable items in the list.

   * Bjorn Benson

     For his safe_malloc (memory checker) package which is used in when
     you build MySQL using one of the `BUILD/compile-*-debug' scripts
     or by manually setting the `-DSAFEMALLOC' flag.

*MySQL 5.0*
   * *Note license-libedit::

   * *Note license-dbug::

   * *Note license-gnu-gpl-2-0::

   * *Note license-gnu-libtool::

   * *Note license-gnu-readline::

   * *Note license-lib-sql::

   * *Note license-regex::

   * *Note license-us-secure-hash::

   * *Note license-libstring::

   * *Note license-zlib::

*MySQL Connector/C*
   * *Note license-dbug::

   * *Note license-regex::

   * *Note license-us-secure-hash::

   * *Note license-zlib::

*MySQL Connector/CPP*
   * *Note license-boost::

*MySQL Connector/J*
   * *Note license-ant-contrib::

   * *Note license-slf4j::

*MySQL Connector/Net*
   * *Note license-antlr-3-3::

   * *Note license-us-secure-hash::

   * *Note license-zlib::

   * *Note license-zlib-net::

*MySQL Proxy*
   * *Note license-glib-proxy::

   * *Note license-gnu-lgpl-2-1::

   * *Note license-libevent::

   * *Note license-lpeg::

   * *Note license-lua::

   * *Note license-luafilesystem::

   * *Note license-pcre::


File: manual.info,  Node: license-ant-contrib,  Next: license-antlr-3-3,  Prev: licenses-third-party,  Up: licenses-third-party

A.1 Ant-Contrib License
=======================

The following software may be included in this product: Ant-Contrib

     Ant-Contrib
     Copyright (c) 2001-2003 Ant-Contrib project. All rights reserved.
     Licensed under the Apache 1.1 License Agreement, a copy of which is reproduced below.

     The Apache Software License, Version 1.1

     Copyright (c) 2001-2003 Ant-Contrib project.  All rights reserved.

      Redistribution and use in source and binary forms, with or without
      modification, are permitted provided that the following conditions
      are met:

      1. Redistributions of source code must retain the above copyright
         notice, this list of conditions and the following disclaimer.

      2. Redistributions in binary form must reproduce the above copyright
         notice, this list of conditions and the following disclaimer in
         the documentation and/or other materials provided with the
         distribution.

      3. The end-user documentation included with the redistribution, if
         any, must include the following acknowlegement:
            "This product includes software developed by the
             Ant-Contrib project (http://sourceforge.net/projects/ant-contrib)."
         Alternately, this acknowlegement may appear in the software itself,
         if and wherever such third-party acknowlegements normally appear.

      4. The name Ant-Contrib must not be used to endorse or promote
         products derived from this software without prior written
         permission. For written permission, please contact
         ant-contrib-developers@lists.sourceforge.net.

      5. Products derived from this software may not be called "Ant-Contrib"
         nor may "Ant-Contrib" appear in their names without prior written
         permission of the Ant-Contrib project.

      THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESSED OR IMPLIED
      WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
      OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
      DISCLAIMED.  IN NO EVENT SHALL THE ANT-CONTRIB PROJECT OR ITS
      CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
      SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
      LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF
      USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
      ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
      OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
      OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
      SUCH DAMAGE.


File: manual.info,  Node: license-antlr-3-3,  Next: license-boost,  Prev: license-ant-contrib,  Up: licenses-third-party

A.2 ANTLR 3.3 License
=====================

     The following software may be included in this product:

     ANTLR 3.3

     ANTLR 3.3 License
     Copyright (c) 2010 Terence Parr
     All rights reserved.
     Redistribution and use in source and binary forms, with or without
     modification, are permitted provided that the following conditions are met:

     Redistributions of source code must retain the above copyright notice, this
     list of conditions and the following disclaimer.
     Redistributions in binary form must reproduce the above copyright notice,
     this list of conditions and the following disclaimer in the documentation
     and/or other materials provided with the distribution.
     Neither the name of the author nor the names of its contributors may be used
     to endorse or promote products derived from this software without specific
     prior written permission.
     THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
     AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
     IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
     ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
     LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
     CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
     SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
     INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
     CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
     ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
     POSSIBILITY OF SUCH DAMAGE.


File: manual.info,  Node: license-boost,  Next: license-libedit,  Prev: license-antlr-3-3,  Up: licenses-third-party

A.3 Boost Library License
=========================

The following software may be included in this product:

*Boost C++ Libraries*

Use of any of this software is governed by the terms of the license
below:

     Boost Software License - Version 1.0 - August 17th, 2003

     Permission is hereby granted, free of charge, to any person or
     organization obtaining a copy of the software and accompanying
     documentation covered by this license (the "Software") to use,
     reproduce, display, distribute, execute, and transmit the Software,
     and to prepare derivative works of the Software, and to permit
     third-parties to whom the Software is furnished to do so, all
     subject to the following:

     The copyright notices in the Software and this entire statement,
     including the above license grant, this restriction and the
     following disclaimer, must be included in all copies of the
     Software, in whole or in part, and all derivative works of the
     Software, unless such copies or derivative works are solely in the
     form of machine-executable object code generated by a source
     language processor.

     THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
     EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
     MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE, TITLE AND
     NON-INFRINGEMENT. IN NO EVENT SHALL THE COPYRIGHT HOLDERS OR ANYONE
     DISTRIBUTING THE SOFTWARE BE LIABLE FOR ANY DAMAGES OR OTHER
     LIABILITY, WHETHER IN CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT
     OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
     IN THE SOFTWARE.


File: manual.info,  Node: license-libedit,  Next: license-dbug,  Prev: license-boost,  Up: licenses-third-party

A.4 Editline Library (`libedit') License
========================================

The following software may be included in this product:

Editline Library (libedit)

Some files are:

     Copyright (c) 1992, 1993
     The Regents of the University of California. All rights reserved.

     This code is derived from software contributed to
     Berkeley by Christos Zoulas of Cornell University.

     Redistribution and use in source and binary forms,
     with or without modification, are permitted provided
     that the following conditions are met:

     1. Redistributions of source code must retain the
       above copyright notice, this list of conditions
       and the following disclaimer.
     2. Redistributions in binary form must reproduce the
       above copyright notice, this list of conditions and
       the following disclaimer in the documentation and/or
       other materials provided with the distribution.
     3. Neither the name of the University nor the names of
       its contributors may be used to endorse or promote
       products derived from this software without specific
       prior written permission.

     THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS
     "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING,
     BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY
     AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO
     EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE FOR ANY
     DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
     CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
     PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
     DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
     AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
     LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING
     IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED
     OF THE POSSIBILITY OF SUCH DAMAGE.

Some files are:

     Copyright (c) 2001 The NetBSD Foundation, Inc.
     All rights reserved.

     This code is derived from software contributed to The NetBSD Foundation

     by Anthony Mallet.

     Redistribution and use in source and binary forms,
     with or without modification, are permitted provided
     that the following conditions are met:

     1. Redistributions of source code must retain the
        above copyright notice, this list of conditions
        and the following disclaimer.
     2. Redistributions in binary form must reproduce the
         above copyright notice, this list of conditions and the
         following disclaimer in the documentation and/or
         other materials provided with the distribution.

     THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC.
     AND CONTRIBUTORS "AS IS" AND ANY EXPRESS OR IMPLIED
     WARRANTIES, INCLUDING, BUT NOT LIMITED  TO, THE IMPLIED
     WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A
     PARTICULAR PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL
     THE FOUNDATION OR CONTRIBUTORS BE LIABLE FOR ANY
     DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
     CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
     PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF
     USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
     CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
     CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE
     OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
     SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH
     DAMAGE.

Some files are:

     Copyright (c) 1997 The NetBSD Foundation, Inc.
     All rights reserved.

     This code is derived from software contributed to The NetBSD Foundation

     by Jaromir Dolecek.

     Redistribution and use in source and binary forms,
     with or without modification, are permitted provided
     that the following conditions are met:

     1. Redistributions of source code must retain the
        above copyright notice, this list of conditions
        and the following disclaimer.
     2. Redistributions in binary form must reproduce
         the above copyright notice, this list of conditions
         and the following disclaimer in the documentation
         and/or other materials provided with the distribution.

     THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC.
     AND CONTRIBUTORS "AS IS" AND ANY EXPRESS OR IMPLIED
     WARRANTIES, INCLUDING, BUT NOT LIMITED  TO, THE IMPLIED
     WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A
     PARTICULAR PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL
     THE FOUNDATION OR CONTRIBUTORS BE LIABLE FOR ANY
     DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
     CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
     PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF
     USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
     CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
     CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE
     OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
     SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH
     DAMAGE.

Some files are:

     Copyright (c) 1998 Todd C. Miller <Todd.Miller@courtesan.com>

     Permission to use, copy, modify, and distribute this
     software for any purpose with or without fee is hereby
     granted, provided that the above copyright notice and
     this permission notice appear in all copies.

     THE SOFTWARE IS PROVIDED "AS IS" AND TODD C. MILLER
     DISCLAIMS ALL WARRANTIES WITH REGARD TO THIS SOFTWARE
     INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY
     AND FITNESS. IN NO EVENT SHALL TODD C. MILLER BE LIABLE
     FOR ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL
     DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM
     LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION
     OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION,
     ARISING OUT OF OR IN CONNECTION WITH THE USE OR
     PERFORMANCE OF THIS SOFTWARE.


File: manual.info,  Node: license-dbug,  Next: license-glib-proxy,  Prev: license-libedit,  Up: licenses-third-party

A.5 Fred Fish's Dbug Library License
====================================

The following software may be included in this product:

Fred Fish's Dbug Library

                                     N O T I C E

                        Copyright Abandoned, 1987, Fred Fish

          This previously copyrighted work has been placed into the  public

          domain  by  the  author  and  may be freely used for any purpose,

          private or commercial.

          Because of the number of inquiries I was receiving about the  use

          of this product in commercially developed works I have decided to

          simply make it public domain to further its unrestricted use.   I

          specifically  would  be  most happy to see this material become a

          part of the standard Unix distributions by AT&T and the  Berkeley

          Computer  Science  Research Group, and a standard part of the GNU

          system from the Free Software Foundation.

          I would appreciate it, as a courtesy, if this notice is  left  in

          all copies and derivative works.  Thank you.

          The author makes no warranty of any kind  with  respect  to  this

          product  and  explicitly disclaims any implied warranties of mer-

          chantability or fitness for any particular purpose.

     The dbug_analyze.c file is subject to the following notice:

          Copyright June 1987, Binayak Banerjee
          All rights reserved.

          This program may be freely distributed under the same terms and
          conditions as Fred Fish's Dbug package.


File: manual.info,  Node: license-glib-proxy,  Next: license-gnu-gpl-2-0,  Prev: license-dbug,  Up: licenses-third-party

A.6 GLib License (for MySQL Proxy)
==================================

The following software may be included in this product:


     GLib

     You are receiving a copy of the GLib library in both source
     and object code in the following [proxy install dir]/lib/ and
     [proxy install dir]/licenses/lgpl folders. The terms of the
     Oracle license do NOT apply to the GLib library; it is licensed
     under the following license, separately from the Oracle programs
     you receive. If you do not wish to install this library, you may
     create an "exclude" file and run tar with the X option, as in
     the following example, but the Oracle program might not operate
     properly or at all without the library:
       tar -xvfX <package-tar-file> <exclude-file>
     where the exclude-file contains, e.g.:
       <package-name>/lib/libglib-2.0.so.0.1600.6
       <package-name>/lib/libglib-2.0.so.0
       ...

     Example:
     tar -xvfX mysql-proxy-0.8.1-solaris10-x86-64bit.tar.gz Exclude

     Exclude File:
     mysql-proxy-0.8.1-solaris10-x86-64bit/lib/libglib-2.0.so
     mysql-proxy-0.8.1-solaris10-x86-64bit/lib/libglib-2.0.so.0
     mysql-proxy-0.8.1-solaris10-x86-64bit/lib/libglib-2.0.so.0.1600.6
     mysql-proxy-0.8.1-solaris10-x86-64bit/lib/libgmodule-2.0.so
     mysql-proxy-0.8.1-solaris10-x86-64bit/lib/libgmodule-2.0.so.0
     mysql-proxy-0.8.1-solaris10-x86-64bit/lib/libgmodule-2.0.so.0.1600.6
     mysql-proxy-0.8.1-solaris10-x86-64bit/lib/libgthread-2.0.so
     mysql-proxy-0.8.1-solaris10-x86-64bit/lib/libgthread-2.0.so.0
     mysql-proxy-0.8.1-solaris10-x86-64bit/lib/libgthread-2.0.so.0.1600.6
     mysql-proxy-0.8.1-solaris10-x86-64bit/licenses/lgpl/glib-2.16.6.tar.gz

This component is licensed under *Note license-gnu-lgpl-2-1::.


File: manual.info,  Node: license-gnu-gpl-2-0,  Next: license-gnu-lgpl-2-1,  Prev: license-glib-proxy,  Up: licenses-third-party

A.7 GNU General Public License Version 2.0, June 1991
=====================================================

     The following applies to all products licensed under the GNU General
     Public License, Version 2.0: You may not use the identified files
     except in compliance with the GNU General Public License, Version
     2.0 (the "License.") You may obtain a copy of the License at
     http://www.gnu.org/licenses/gpl-2.0.txt. A copy of the license is
     also reproduced below. Unless required by applicable law or agreed
     to in writing, software distributed under the License is distributed
     on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND,
     either express or implied. See the License for the specific language
     governing permissions and limitations under the License.

     GNU GENERAL PUBLIC LICENSE
     Version 2, June 1991

     Copyright (C) 1989, 1991 Free Software Foundation, Inc.,
     51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
     Everyone is permitted to copy and distribute verbatim
     copies of this license document, but changing it is not
     allowed.

                          Preamble

       The licenses for most software are designed to take away your
     freedom to share and change it.  By contrast, the GNU General Public
     License is intended to guarantee your freedom to share and change free
     software--to make sure the software is free for all its users.  This
     General Public License applies to most of the Free Software
     Foundation's software and to any other program whose authors commit to
     using it.  (Some other Free Software Foundation software is covered by
     the GNU Lesser General Public License instead.)  You can apply it to
     your programs, too.

       When we speak of free software, we are referring to freedom, not
     price.  Our General Public Licenses are designed to make sure that you
     have the freedom to distribute copies of free software (and charge for
     this service if you wish), that you receive source code or can get it
     if you want it, that you can change the software or use pieces of it
     in new free programs; and that you know you can do these things.

       To protect your rights, we need to make restrictions that forbid
     anyone to deny you these rights or to ask you to surrender the rights.
     These restrictions translate to certain responsibilities for you if you
     distribute copies of the software, or if you modify it.

       For example, if you distribute copies of such a program, whether
     gratis or for a fee, you must give the recipients all the rights that
     you have.  You must make sure that they, too, receive or can get the
     source code.  And you must show them these terms so they know their
     rights.

       We protect your rights with two steps: (1) copyright the software,
     and (2) offer you this license which gives you legal permission to
     copy, distribute and/or modify the software.

       Also, for each author's protection and ours, we want to make certain
     that everyone understands that there is no warranty for this free
     software.  If the software is modified by someone else and passed on,
     we want its recipients to know that what they have is not the original,
     so that any problems introduced by others will not reflect on the
     original authors' reputations.

       Finally, any free program is threatened constantly by software
     patents.  We wish to avoid the danger that redistributors of a free
     program will individually obtain patent licenses, in effect making the
     program proprietary.  To prevent this, we have made it clear that any
     patent must be licensed for everyone's free use or not licensed at all.

       The precise terms and conditions for copying, distribution and
     modification follow.

                         GNU GENERAL PUBLIC LICENSE
        TERMS AND CONDITIONS FOR COPYING, DISTRIBUTION AND MODIFICATION

       0. This License applies to any program or other work which contains
     a notice placed by the copyright holder saying it may be distributed
     under the terms of this General Public License.  The "Program", below,
     refers to any such program or work, and a "work based on the Program"
     means either the Program or any derivative work under copyright law:
     that is to say, a work containing the Program or a portion of it,
     either verbatim or with modifications and/or translated into another
     language.  (Hereinafter, translation is included without limitation in
     the term "modification".)  Each licensee is addressed as "you".

     Activities other than copying, distribution and modification are not
     covered by this License; they are outside its scope.  The act of
     running the Program is not restricted, and the output from the Program
     is covered only if its contents constitute a work based on the
     Program (independent of having been made by running the Program).
     Whether that is true depends on what the Program does.

       1. You may copy and distribute verbatim copies of the Program's
     source code as you receive it, in any medium, provided that you
     conspicuously and appropriately publish on each copy an appropriate
     copyright notice and disclaimer of warranty; keep intact all the
     notices that refer to this License and to the absence of any warranty;
     and give any other recipients of the Program a copy of this License
     along with the Program.

     You may charge a fee for the physical act of transferring a copy, and
     you may at your option offer warranty protection in exchange for a fee.

       2. You may modify your copy or copies of the Program or any portion
     of it, thus forming a work based on the Program, and copy and
     distribute such modifications or work under the terms of Section 1
     above, provided that you also meet all of these conditions:

         a) You must cause the modified files to carry prominent notices
         stating that you changed the files and the date of any change.

         b) You must cause any work that you distribute or publish, that in
         whole or in part contains or is derived from the Program or any
         part thereof, to be licensed as a whole at no charge to all third
         parties under the terms of this License.

         c) If the modified program normally reads commands interactively
         when run, you must cause it, when started running for such
         interactive use in the most ordinary way, to print or display an
         announcement including an appropriate copyright notice and a
         notice that there is no warranty (or else, saying that you provide
         a warranty) and that users may redistribute the program under
         these conditions, and telling the user how to view a copy of this
         License.  (Exception: if the Program itself is interactive but
         does not normally print such an announcement, your work based on
         the Program is not required to print an announcement.)

     These requirements apply to the modified work as a whole.  If
     identifiable sections of that work are not derived from the Program,
     and can be reasonably considered independent and separate works in
     themselves, then this License, and its terms, do not apply to those
     sections when you distribute them as separate works.  But when you
     distribute the same sections as part of a whole which is a work based
     on the Program, the distribution of the whole must be on the terms of
     this License, whose permissions for other licensees extend to the
     entire whole, and thus to each and every part regardless of who wrote it.

     Thus, it is not the intent of this section to claim rights or contest
     your rights to work written entirely by you; rather, the intent is to
     exercise the right to control the distribution of derivative or
     collective works based on the Program.

     In addition, mere aggregation of another work not based on the Program
     with the Program (or with a work based on the Program) on a volume of
     a storage or distribution medium does not bring the other work under
     the scope of this License.

       3. You may copy and distribute the Program (or a work based on it,
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File: manual.info,  Node: license-gnu-lgpl-2-1,  Next: license-gnu-libtool,  Prev: license-gnu-gpl-2-0,  Up: licenses-third-party

A.8 GNU Lesser General Public License Version 2.1, February 1999
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     integrity of the free software distribution system which is
     implemented by public license practices.  Many people have made
     generous contributions to the wide range of software distributed
     through that system in reliance on consistent application of that
     system; it is up to the author/donor to decide if he or she is willing
     to distribute software through any other system and a licensee cannot
     impose that choice.

     This section is intended to make thoroughly clear what is believed to
     be a consequence of the rest of this License.

       12. If the distribution and/or use of the Library is restricted in
     certain countries either by patents or by copyrighted interfaces, the
     original copyright holder who places the Library under this License
     may add an explicit geographical distribution limitation excluding
     those countries, so that distribution is permitted only in or among
     countries not thus excluded.  In such case, this License incorporates
     the limitation as if written in the body of this License.

       13. The Free Software Foundation may publish revised and/or new
     versions of the Lesser General Public License from time to time.
     Such new versions will be similar in spirit to the present version,
     but may differ in detail to address new problems or concerns.

     Each version is given a distinguishing version number.  If the Library
     specifies a version number of this License which applies to it and
     "any later version", you have the option of following the terms and
     conditions either of that version or of any later version published by
     the Free Software Foundation.  If the Library does not specify a
     license version number, you may choose any version ever published by
     the Free Software Foundation.

       14. If you wish to incorporate parts of the Library into other free
     programs whose distribution conditions are incompatible with these,
     write to the author to ask for permission.  For software which is
     copyrighted by the Free Software Foundation, write to the Free
     Software Foundation; we sometimes make exceptions for this.  Our
     decision will be guided by the two goals of preserving the free status
     of all derivatives of our free software and of promoting the sharing
     and reuse of software generally.

                                 NO WARRANTY

       15. BECAUSE THE LIBRARY IS LICENSED FREE OF CHARGE, THERE IS NO
     WARRANTY FOR THE LIBRARY, TO THE EXTENT PERMITTED BY APPLICABLE LAW.
     EXCEPT WHEN OTHERWISE STATED IN WRITING THE COPYRIGHT HOLDERS AND/OR
     OTHER PARTIES PROVIDE THE LIBRARY "AS IS" WITHOUT WARRANTY OF ANY
     KIND, EITHER EXPRESSED OR IMPLIED, INCLUDING, BUT NOT LIMITED TO, THE
     IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
     PURPOSE.  THE ENTIRE RISK AS TO THE QUALITY AND PERFORMANCE OF THE
     LIBRARY IS WITH YOU.  SHOULD THE LIBRARY PROVE DEFECTIVE, YOU ASSUME
     THE COST OF ALL NECESSARY SERVICING, REPAIR OR CORRECTION.

       16. IN NO EVENT UNLESS REQUIRED BY APPLICABLE LAW OR AGREED TO IN
     WRITING WILL ANY COPYRIGHT HOLDER, OR ANY OTHER PARTY WHO MAY MODIFY
     AND/OR REDISTRIBUTE THE LIBRARY AS PERMITTED ABOVE, BE LIABLE TO YOU
     FOR DAMAGES, INCLUDING ANY GENERAL, SPECIAL, INCIDENTAL OR
     CONSEQUENTIAL DAMAGES ARISING OUT OF THE USE OR INABILITY TO USE THE
     LIBRARY (INCLUDING BUT NOT LIMITED TO LOSS OF DATA OR DATA BEING
     RENDERED INACCURATE OR LOSSES SUSTAINED BY YOU OR THIRD PARTIES OR A
     FAILURE OF THE LIBRARY TO OPERATE WITH ANY OTHER SOFTWARE), EVEN IF
     SUCH HOLDER OR OTHER PARTY HAS BEEN ADVISED OF THE POSSIBILITY OF SUCH
     DAMAGES.

                          END OF TERMS AND CONDITIONS

                How to Apply These Terms to Your New Libraries

       If you develop a new library, and you want it to be of the greatest
     possible use to the public, we recommend making it free software that
     everyone can redistribute and change.  You can do so by permitting
     redistribution under these terms (or, alternatively, under the terms
     of the ordinary General Public License).

       To apply these terms, attach the following notices to the library.
     It is safest to attach them to the start of each source file to most
     effectively convey the exclusion of warranty; and each file should
     have at least the "copyright" line and a pointer to where the full
     notice is found.

         <one line to give the library's name and a brief idea of what it does.>
         Copyright (C) <year>  <name of author>

         This library is free software; you can redistribute it and/or
         modify it under the terms of the GNU Lesser General Public
         License as published by the Free Software Foundation; either
         version 2.1 of the License, or (at your option) any later version.

         This library is distributed in the hope that it will be useful,
         but WITHOUT ANY WARRANTY; without even the implied warranty of
         MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
         Lesser General Public License for more details.

         You should have received a copy of the GNU Lesser General Public
         License along with this library; if not, write to the Free Software
         Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
         02110-1301  USA

     Also add information on how to contact you by electronic and paper mail.

     You should also get your employer (if you work as a programmer) or your
     school, if any, to sign a "copyright disclaimer" for the library, if
     necessary.  Here is a sample; alter the names:

       Yoyodyne, Inc., hereby disclaims all copyright interest in the
       library `Frob' (a library for tweaking knobs) written by James
       Random Hacker.

       <signature of Ty Coon>, 1 April 1990
       Ty Coon, President of Vice

     That's all there is to it!


File: manual.info,  Node: license-gnu-libtool,  Next: license-gnu-readline,  Prev: license-gnu-lgpl-2-1,  Up: licenses-third-party

A.9 GNU Libtool License
=======================

The following software may be included in this product:

GNU Libtool (The GNU Portable Library Tool)

     If you are receiving a copy of the Oracle software in
     source code, you are also receiving a copy of two files
     (ltmain.sh and ltdl.h) generated by the GNU Libtool in
     source code. If you received the Oracle software under
     a license other than a commercial (non-GPL) license,
     then the terms of the Oracle license do NOT apply to
     these files from GNU Libtool; they are licensed under
     the following licenses, separately from the Oracle
     programs you receive.

     Oracle elects to use GNU General Public License version
     2 (GPL) for any software where a choice of GPL or GNU
     Lesser/Library General Public License (LGPL) license
     versions are made available with the language indicating
     that GPL/LGPL or any later version may be used, or where
     a choice of which version of the GPL/LGPL is applied is
     unspecified.

     From GNU Libtool:

     ltmain.sh - Provide generalized library-building support
     services.
     NOTE: Changing this file will not affect anything until
     you rerun configure.
     Copyright (C) 1996, 1997, 1998, 1999, 2000, 2001, 2003, 2004,
     2005, 2006, 2007 Free Software Foundation, Inc.
     Originally by Gordon Matzigkeit, 1996

     This program is free software; you can redistribute it
     and/or modify it under the terms of the GNU General
     Public License as published by the Free Software Foundation;
     either version 2 of the License, or (at your option) any
     later version.

     This program is distributed in the hope that it will be
     useful, but WITHOUT ANY WARRANTY; without even the implied
     warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR
     PURPOSE. See the GNU General Public License for more
     details. You should have received a copy of the GNU General
     Public License along with this program; if not, write to
     the Free Software Foundation, Inc., 51 Franklin Street,
     Fifth Floor, Boston, MA 02110-1301, USA.

     As a special exception to the GNU General Public License,
     if you distribute this file as part of a program that
     contains a configuration script generated by Autoconf,
     you may include it under the same distribution terms that
     you use for the rest of that program.

This component is licensed under *Note license-gnu-gpl-2-0::


File: manual.info,  Node: license-gnu-readline,  Next: license-lib-sql,  Prev: license-gnu-libtool,  Up: licenses-third-party

A.10 GNU Readline License
=========================

The following software may be included in this product:

GNU Readline Library

     GNU Readline Library
     With respect to MySQL Server/Cluster software licensed
     under GNU General Public License, you are receiving a
     copy of the GNU Readline Library in source code. The
     terms of any Oracle license that might accompany the
     Oracle programs do NOT apply to the GNU Readline Library;
     it is licensed under the following license, separately
     from the Oracle programs you receive. Oracle elects to
     use GNU General Public License version 2 (GPL) for any
     software where a choice of GPL license versions are
     made available with the language indicating that GPLv2
     or any later version may be used, or where a choice of
     which version of the GPL is applied is unspecified.

This component is licensed under *Note license-gnu-gpl-2-0::


File: manual.info,  Node: license-lib-sql,  Next: license-libevent,  Prev: license-gnu-readline,  Up: licenses-third-party

A.11 `lib_sql.cc' License
=========================

The following software may be included in this product:

`lib_sql.cc'

     Copyright (c) 2000
     SWsoft company

     This material is provided "as is", with absolutely no warranty
     expressed or implied. Any use is at your own risk.

     Permission to use or copy this software for any purpose is hereby
     granted without fee, provided the above notices are retained on
     all copies. Permission to modify the code and to distribute modified
     code is granted, provided the above notices are retained, and a
     notice that the code was modified is included with the above copyright
     notice.

     This code was modified by the MySQL team.


File: manual.info,  Node: license-libevent,  Next: license-lpeg,  Prev: license-lib-sql,  Up: licenses-third-party

A.12 `libevent' License
=======================

The following software may be included in this product:

     libevent

     Copyright (c) 2000-2007 Niels Provos <provos@citi.umich.edu>
     All rights reserved.

     Redistribution and use in source and binary forms, with or without
     modification, are permitted provided that the following conditions
     are met:
     1. Redistributions of source code must retain the above copyright
        notice, this list of conditions and the following disclaimer.
     2. Redistributions in binary form must reproduce the above copyright
        notice, this list of conditions and the following disclaimer in the
        documentation and/or other materials provided with the distribution.
     3. The name of the author may not be used to endorse or promote products
        derived from this software without specific prior written permission.

     THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
     IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
     OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
     IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
     INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
     NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
     DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
     THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
     (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
     THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE

     ==
     Parts developed by Adam Langley
     ==

     ==
     log.c
     Based on err.c, which was adapted from OpenBSD libc *err*warncode.

     Copyright (c) 2005 Nick Mathewson
     Copyright (c) 2000 Dug Song
     Copyright (c) 1993 The Regents of the University of California.
     All rights reserved.

     Redistribution and use in source and binary forms, with or without
     modification, are permitted provided that the following conditions
     are met:
     1. Redistributions of source code must retain the above copyright
        notice, this list of conditions and the following disclaimer.
     2. Redistributions in binary form must reproduce the above copyright
        notice, this list of conditions and the following disclaimer in
        the documentation and/or other materials provided with the
        distribution.
     3. Neither the name of the University nor the names of its
        contributors may be used to endorse or promote products derived
        from this software without specific prior written permission.

     THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS "AS IS"
     AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
     TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A
     PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS
     OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
     SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
     LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF
     USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
     AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
     LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING
     IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF
     THE POSSIBILITY OF SUCH DAMAGE.
     ==

     ==
     min_heap.h

     Copyright (c) 2006 Maxim Yegorushkin
     All rights reserved.

     Redistribution and use in source and binary forms, with or without
     modification, are permitted provided that the following conditions
     are met:
     1. Redistributions of source code must retain the above copyright
        notice, this list of conditions and the following disclaimer.
     2. Redistributions in binary form must reproduce the above copyright
        notice, this list of conditions and the following disclaimer in
        the documentation and/or other materials provided with the
        distribution.
     3. The name of the author may not be used to endorse or promote
        products derived from this software without specific prior
        written permission.

     THIS SOFTWARE IS PROVIDED BY THE AUTHOR "AS IS" AND ANY EXPRESS
     OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
     WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
     ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY
     DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
     DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE
     GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
     INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER
     IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR
     OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN
     IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
     ==

     ==
     win32.c

     Copyright 2000-2002 Niels Provos
     Copyright 2003 Michael A. Davis
     All rights reserved.

     Redistribution and use in source and binary forms, with or without
     modification, are permitted provided that the following conditions
     are met:
     1. Redistributions of source code must retain the above copyright
        notice, this list of conditions and the following disclaimer.
     2. Redistributions in binary form must reproduce the above copyright
        notice, this list of conditions and the following disclaimer in
        the documentation and/or other materials provided with the
        distribution.
     3.  The name of the author may not be used to endorse or promote
         products derived from this software without specific prior
         written permission.

     THIS SOFTWARE IS PROVIDED BY THE AUTHOR "AS IS" AND ANY EXPRESS
     OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
     WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
     ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY
     DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
     DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE
     GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
     INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER
     IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR
     OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN
     IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
     ==


File: manual.info,  Node: license-lpeg,  Next: license-lua,  Prev: license-libevent,  Up: licenses-third-party

A.13 `LPeg' Library License
===========================

The following software may be included in this product:

     LPeg

     Use of any of this software is governed by the terms of the license below:

     Copyright (C) 2008 Lua.org, PUC-Rio.

     Permission is hereby granted, free of charge, to any person obtaining a copy of
     this software and associated documentation files (the "Software"), to deal in
     the Software without restriction, including without limitation the rights to
     use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of
     the Software, and to permit persons to whom the Software is furnished to do so,
     subject to the following conditions:

     The above copyright notice and this permission notice shall be included in all
     copies or substantial portions of the Software.

     THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
     IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS
     FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR
     COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER
     IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
     CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.


File: manual.info,  Node: license-lua,  Next: license-luafilesystem,  Prev: license-lpeg,  Up: licenses-third-party

A.14 Lua (liblua) License
=========================

The following software may be included in this product:

     Lua (liblua)

     Copyright (C) 1994-2008 Lua.org, PUC-Rio.

     Permission is hereby granted, free of charge, to any person obtaining
     a copy of this software and associated documentation files (the
     "Software"), to deal in the Software without restriction, including
     without limitation the rights to use, copy, modify, merge, publish,
     distribute, sublicense, and/or sell copies of the Software, and to
     permit persons to whom the Software is furnished to do so, subject
     to the following conditions:

     The above copyright notice and this permission notice shall be
     included in all copies or substantial portions of the Software.

     THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
     EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES
     OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
     NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT
     HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY,
     WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
     FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
     OTHER DEALINGS IN THE SOFTWARE.


File: manual.info,  Node: license-luafilesystem,  Next: license-pcre,  Prev: license-lua,  Up: licenses-third-party

A.15 `LuaFileSystem' Library License
====================================

The following software may be included in this product:

     LuaFileSystem

     Copyright (C) 2003 Kepler Project.

     Permission is hereby granted, free of charge, to any person obtaining
     a copy of this software and associated documentation files (the
     "Software"), to deal in the Software without restriction, including
     without limitation the rights to use, copy, modify, merge, publish,
     distribute, sublicense, and/or sell copies of the Software, and to
     permit persons to whom the Software is furnished to do so, subject
     to the following conditions:

     The above copyright notice and this permission notice shall be
     included in all copies or substantial portions of the Software.

     THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
     EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
     MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.
     IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR
     ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF
     CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
     WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.


File: manual.info,  Node: license-pcre,  Next: license-regex,  Prev: license-luafilesystem,  Up: licenses-third-party

A.16 PCRE License
=================

The following software may be included in this product:

PCRE (Perl Compatible Regular Expressions) Library

     PCRE LICENCE

     PCRE is a library of functions to support regular expressions
     whose syntax and semantics are as close as possible to those
     of the Perl 5 language.

     Release 7 of PCRE is distributed under the terms of the "BSD"
     licence, as specified below. The documentation for PCRE,
     supplied in the "doc" directory, is distributed under the same
     terms as the software itself.

     The basic library functions are written in C and are
     freestanding. Also included in the distribution is a set
     of C++ wrapper functions.

     THE BASIC LIBRARY FUNCTIONS
     ---------------------------
     Written by:       Philip Hazel
     Email local part: ph10
     Email domain:     cam.ac.uk

     University of Cambridge Computing Service,
     Cambridge, England. Phone: +44 1223 334714.

     Copyright (c) 1997-2006 University of Cambridge
     All rights reserved.

     THE C++ WRAPPER FUNCTIONS
     -------------------------
     Contributed by:   Google Inc.

     Copyright (c) 2006, Google Inc.
     All rights reserved.

     THE "BSD" LICENCE
     -----------------

     Redistribution and use in source and binary forms,
     with or without modification, are permitted provided
     that the following conditions are met:

     * Redistributions of source code must retain the above
       copyright notice, this list of conditions and the
       following disclaimer.
     * Redistributions in binary form must reproduce the
       above copyright notice, this list of conditions and
       the following disclaimer in the documentation and/or
       other materials provided with the distribution.
     * Neither the name of the University of Cambridge nor
       the name of Google Inc. nor the names of their contributors
       may be used to endorse or promote products derived from
       this software without specific prior written permission.

     THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND
     CONTRIBUTORS "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES,
     INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
     MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
     DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS
     BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY,
     OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT
     OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS;
     OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
     LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
     NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
     THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.

     End


File: manual.info,  Node: license-regex,  Next: license-us-secure-hash,  Prev: license-pcre,  Up: licenses-third-party

A.17 RegEX-Spencer Library License
==================================

The following software may be included in this product: Henry Spencer's
Regular-Expression Library (RegEX-Spencer)

     Copyright 1992, 1993, 1994 Henry Spencer.  All rights reserved.
     This software is not subject to any license of the American Telephone
     and Telegraph Company or of the Regents of the University of California.

     Permission is granted to anyone to use this software for any purpose on
     any computer system, and to alter it and redistribute it, subject
     to the following restrictions:

     1. The author is not responsible for the consequences of use of this
        software, no matter how awful, even if they arise from flaws in it.

     2. The origin of this software must not be misrepresented, either by
        explicit claim or by omission.  Since few users ever read sources,
        credits must appear in the documentation.

     3. Altered versions must be plainly marked as such, and must not be
        misrepresented as being the original software.  Since few users
        ever read sources, credits must appear in the documentation.

     4. This notice may not be removed or altered.


File: manual.info,  Node: license-us-secure-hash,  Next: license-libstring,  Prev: license-regex,  Up: licenses-third-party

A.18 RFC 3174 - US Secure Hash Algorithm 1 (SHA1) License
=========================================================

The following software may be included in this product:

RFC 3174 - US Secure Hash Algorithm 1 (SHA1)

     RFC 3174 - US Secure Hash Algorithm 1 (SHA1)

     Copyright (C) The Internet Society (2001).  All Rights Reserved.

     This document and translations of it may be copied and furnished to
     others, and derivative works that comment on or otherwise explain it
     or assist in its implementation may be prepared, copied, published
     and distributed, in whole or in part, without restriction of any
     kind, provided that the above copyright notice and this paragraph are
     included on all such copies and derivative works.  However, this
     document itself may not be modified in any way, such as by removing
     the copyright notice or references to the Internet Society or other
     Internet organizations, except as needed for the purpose of
     developing Internet standards in which case the procedures for
     copyrights defined in the Internet Standards process must be
     followed, or as required to translate it into languages other than
     English.

     The limited permissions granted above are perpetual and will not be
     revoked by the Internet Society or its successors or assigns.

     This document and the information contained herein is provided on an
     "AS IS" basis and THE INTERNET SOCIETY AND THE INTERNET ENGINEERING
     TASK FORCE DISCLAIMS ALL WARRANTIES, EXPRESS OR IMPLIED, INCLUDING
     BUT NOT LIMITED TO ANY WARRANTY THAT THE USE OF THE INFORMATION
     HEREIN WILL NOT INFRINGE ANY RIGHTS OR ANY IMPLIED WARRANTIES OF
     MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE.

     Acknowledgement
     Funding for the RFC Editor function is currently provided by the
     Internet Society.


File: manual.info,  Node: license-libstring,  Next: license-slf4j,  Prev: license-us-secure-hash,  Up: licenses-third-party

A.19 Richard A. O'Keefe String Library License
==============================================

The following software may be included in this product:

Richard A. O'Keefe String Library

     The Richard O'Keefe String Library is subject to the following notice:

     These files are in the public domain.  This includes getopt.c, which
     is the work of Henry Spencer, University of Toronto Zoology, who
     says of it "None of this software is derived from Bell software. I
     had no access to the source for Bell's versions at the time I wrote
     it.  This software is hereby explicitly placed in the public domain.
     It may be used for any purpose on any machine by anyone." I would
     greatly prefer it if *my* material received no military use.

     The t_ctype.h file is subject to the following notice:

     Copyright (C) 1998, 1999 by Pruet Boonma, all rights reserved.
     Copyright (C) 1998 by Theppitak Karoonboonyanan, all rights reserved.

       Permission to use, copy, modify, distribute and sell this software and its
     documentation for any purpose is hereby granted without fee, provided that the above
     copyright notice appear in all copies.

       Smaphan Raruenrom and Pruet Boonma makes no representations about
     the suitability of this software for any purpose. It is provided
     "as is" without express or implied warranty.


File: manual.info,  Node: license-slf4j,  Next: license-zlib,  Prev: license-libstring,  Up: licenses-third-party

A.20 Simple Logging Facade for Java (SLF4J) License
===================================================

The following software may be included in this product:

     Simple Logging Facade for Java (SLF4J)

     Copyright (c) 2004-2008 QOS.ch
     All rights reserved.

     Permission is hereby granted, free of charge,
     to any person obtaining a copy of this software
     and associated documentation files (the "Software"),
     to deal in the Software without restriction, including
     without limitation the rights to use, copy, modify,
     merge, publish, distribute, sublicense, and/or sell
     copies of the Software, and to permit persons to whom
     the Software is furnished to do so, subject to the
     following conditions:

     The above copyright notice and this permission notice
     shall be included in all copies or substantial portions
     of the Software.

     THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY
     OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT
     LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS
     FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO
     EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE
     FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN
     AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
     OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE
     OR OTHER DEALINGS IN THE SOFTWARE.


File: manual.info,  Node: license-zlib,  Next: license-zlib-net,  Prev: license-slf4j,  Up: licenses-third-party

A.21 `zlib' License
===================

The following software may be included in this product:

zlib

Oracle gratefully acknowledges the contributions of Jean-loup Gailly
and Mark Adler in creating the zlib general purpose compression library
which is used in this product.

     zlib.h -- interface of the 'zlib' general purpose compression library
     Copyright (C) 1995-2004 Jean-loup Gailly and Mark Adler

     zlib.h -- interface of the 'zlib' general purpose compression library
     version 1.2.3, July 18th, 2005
     Copyright (C) 1995-2005 Jean-loup Gailly and Mark Adler

     zlib.h -- interface of the 'zlib' general purpose compression library
     version 1.2.5, April 19th, 2010
     Copyright (C) 1995-2010 Jean-loup Gailly and Mark Adler

     This software is provided 'as-is', without any express or implied warranty.
     In no event will the authors be held liable for any damages arising from the
     use of this software. Permission is granted to anyone to use this software
     for any purpose,including commercial applications, and to alter it and
     redistribute it freely, subject to the following restrictions:

     1. The origin of this software must not be misrepresented; you must not
        claim that you wrote the original software. If you use this software
        in a product, an acknowledgment in the product documentation would
        be appreciated but is not required.
     2. Altered source versions must be plainly marked as such, and must not
        be misrepresented as being the original software.
     3. This notice may not be removed or altered from any source distribution.

     Jean-loup Gailly jloup@gzip.org
     Mark Adler madler@alumni.caltech.edu


File: manual.info,  Node: license-zlib-net,  Prev: license-zlib,  Up: licenses-third-party

A.22 ZLIB.NET License
=====================

The following software may be included in this product:

     ZLIB.NET

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File: manual.info,  Node: faqs,  Next: error-handling,  Prev: licenses-third-party,  Up: Top

Appendix B MySQL 5.0 Frequently Asked Questions
***********************************************

* Menu:

* faqs-general::                 MySQL 5.0 FAQ: General
* faqs-storage-engines::         MySQL 5.0 FAQ: Storage Engines
* faqs-sql-modes::               MySQL 5.0 FAQ: Server SQL Mode
* faqs-stored-procs::            MySQL 5.0 FAQ: Stored Procedures and Functions
* faqs-triggers::                MySQL 5.0 FAQ: Triggers
* faqs-views::                   MySQL 5.0 FAQ: Views
* faqs-information-schema::      MySQL 5.0 FAQ: `INFORMATION_SCHEMA'
* faqs-migration::               MySQL 5.0 FAQ: Migration
* faqs-security::                MySQL 5.0 FAQ: Security
* faqs-mysql-cluster::           MySQL 5.0 FAQ: MySQL Cluster
* faqs-cjk::                     MySQL 5.0 FAQ: MySQL Chinese, Japanese, and Korean Character Sets
* faqs-connectors-apis::         MySQL 5.0 FAQ: Connectors & APIs
* faqs-replication::             MySQL 5.0 FAQ: Replication
* faqs-mysql-drbd-heartbeat::    MySQL 5.0 FAQ: MySQL, DRBD, and Heartbeat


File: manual.info,  Node: faqs-general,  Next: faqs-storage-engines,  Prev: faqs,  Up: faqs

B.1 MySQL 5.0 FAQ: General
==========================

*Questions*
   * B.1.1: Which version of MySQL is production-ready (GA)?

   * B.1.2: What is the state of development (non-GA) versions?

   * B.1.3: Can MySQL 5.0 do subqueries?

   * B.1.4: Can MySQL 5.0 perform multiple-table inserts, updates, and
     deletes?

   * B.1.5: Does MySQL 5.0 have a Query Cache? Does it work on Server,
     Instance or Database?

   * B.1.6: Does MySQL 5.0 have Sequences?

   * B.1.7: Does MySQL 5.0 have a `NOW()' function with fractions of
     seconds?

   * B.1.8: Does MySQL 5.0 work with multi-core processors?

   * B.1.9: Why do I see multiple processes for `mysqld'?

   * B.1.10: Have there been there any improvements in error reporting
     when foreign keys fail? Does MySQL now report which column and
     reference failed?

   * B.1.11: Can MySQL 5.0 perform ACID transactions?

*Questions and Answers* *B.1.1: ** Which version of MySQL is
production-ready (GA)?  *

At the time of writing this (December 2011), MySQL 5.5, MySQL 5.1, and
MySQL 5.0 are supported for production use.

MySQL 5.5 achieved General Availability (GA) status with MySQL 5.5.8,
which was released for production use on 3 December 2010.

MySQL 5.1 achieved General Availability (GA) status with MySQL 5.1.30,
which was released for production use on 14 November 2008.

MySQL 5.0 achieved General Availability (GA) status with MySQL 5.0.15,
which was released for production use on 19 October 2005. Note that
active development for MySQL 5.0 has ended.

*B.1.2: ** What is the state of development (non-GA) versions?  *

MySQL follows a milestone release model that introduces
pre-production-quality features and stabilizes them to release quality
(see `http://forge.mysql.com/wiki/Development_Cycle').  This process
then repeats, so releases cycle between pre-production and release
quality status. Please check the change logs to identify the status of
a given release.

MySQL 5.4 was a development series. Work on this series has ceased.

MySQL 5.5 is being actively developed using the milestone release
methodology described above.

MySQL 5.6 is being actively developed using the milestone release
methodology described above.

MySQL 6.0 was a development series. Work on this series has ceased.

*B.1.3: ** Can MySQL 5.0 do subqueries?  *

Yes. See *Note subqueries::.

*B.1.4: ** Can MySQL 5.0 perform multiple-table inserts, updates, and
deletes?  *

Yes. For the syntax required to perform multiple-table updates, see
*Note update::; for that required to perform multiple-table deletes,
see *Note delete::.

A multiple-table insert can be accomplished using a trigger whose `FOR
EACH ROW' clause contains multiple *Note `INSERT': insert. statements
within a `BEGIN ... END' block. See *Note triggers::.

*B.1.5: ** Does MySQL 5.0 have a Query Cache? Does it work on Server,
Instance or Database?  *

Yes. The query cache operates on the server level, caching complete
result sets matched with the original query string. If an exactly
identical query is made (which often happens, particularly in web
applications), no parsing or execution is necessary; the result is sent
directly from the cache. Various tuning options are available. See
*Note query-cache::.

*B.1.6: ** Does MySQL 5.0 have Sequences?  *

No. However, MySQL has an `AUTO_INCREMENT' system, which in MySQL 5.0
can also handle inserts in a multi-master replication setup. With the
`auto_increment_increment' and `auto_increment_offset' system
variables, you can set each server to generate auto-increment values
that don't conflict with other servers. The `auto_increment_increment'
value should be greater than the number of servers, and each server
should have a unique offset.

*B.1.7: ** Does MySQL 5.0 have a `NOW()' function with fractions of
seconds?  *

No. This is on the MySQL roadmap as a `rolling feature'. This means
that it is not a flagship feature, but will be implemented, development
time permitting. Specific customer demand may change this scheduling.

However, MySQL does parse time strings with a fractional component. See
*Note time::.

*B.1.8: ** Does MySQL 5.0 work with multi-core processors?  *

Yes. MySQL is fully multi-threaded, and will make use of multiple CPUs,
provided that the operating system supports them.

*B.1.9: ** Why do I see multiple processes for `mysqld'?  *

When using LinuxThreads, you should see a minimum of three *Note
`mysqld': mysqld. processes running. These are in fact threads. There
is one thread for the LinuxThreads manager, one thread to handle
connections, and one thread to handle alarms and signals.

*B.1.10: ** Have there been there any improvements in error reporting
when foreign keys fail? Does MySQL now report which column and
reference failed?  *

The foreign key support in `InnoDB' has seen improvements in each major
version of MySQL. Foreign key support generic to all storage engines is
scheduled for MySQL 6.x; this should resolve any inadequacies in the
current storage engine specific implementation.

*B.1.11: ** Can MySQL 5.0 perform ACID transactions?  *

Yes. All current MySQL versions support transactions. The `InnoDB'
storage engine offers full ACID transactions with row-level locking,
multi-versioning, nonlocking repeatable reads, and all four SQL
standard isolation levels.

The *Note `NDB': mysql-cluster. storage engine supports the `READ
COMMITTED' transaction isolation level only.


File: manual.info,  Node: faqs-storage-engines,  Next: faqs-sql-modes,  Prev: faqs-general,  Up: faqs

B.2 MySQL 5.0 FAQ: Storage Engines
==================================

*Questions*
   * B.2.1: Where can I obtain complete documentation for MySQL storage
     engines?

   * B.2.2: Are there any new storage engines in MySQL 5.0?

   * B.2.3: Have any storage engines been removed in MySQL 5.0?

   * B.2.4: What are the unique benefits of the `ARCHIVE' storage
     engine?

   * B.2.5: Do the new features in MySQL 5.0 apply to all storage
     engines?

*Questions and Answers* *B.2.1: ** Where can I obtain complete
documentation for MySQL storage engines?  *

See *Note storage-engines::. That chapter contains information about
all MySQL storage engines except for the *Note `NDB': mysql-cluster.
storage engine used for MySQL Cluster; *Note `NDB': mysql-cluster. is
covered in *Note mysql-cluster::.

*B.2.2: ** Are there any new storage engines in MySQL 5.0?  *

Yes. The `FEDERATED' storage engine, new in MySQL 5.0, allows the
server to access tables on other (remote) servers. See *Note
federated-storage-engine::.

*B.2.3: ** Have any storage engines been removed in MySQL 5.0?  *

Yes. MySQL 5.0 no longer supports the `ISAM' storage engine. If you
have any existing `ISAM' tables from previous versions of MySQL, you
should convert these to `MyISAM' before upgrading to MySQL 5.0.

*B.2.4: ** What are the unique benefits of the `ARCHIVE' storage engine?
*

The `ARCHIVE' storage engine is ideally suited for storing large
amounts of data without indexes; it has a very small footprint, and
performs selects using table scans. See *Note archive-storage-engine::,
for details.

*B.2.5: ** Do the new features in MySQL 5.0 apply to all storage
engines?  *

The general new features such as views, stored procedures, triggers,
`INFORMATION_SCHEMA', precision math (*Note `DECIMAL': numeric-types.
column type), and the *Note `BIT': numeric-types. column type, apply to
all storage engines. There are also additions and changes for specific
storage engines.


File: manual.info,  Node: faqs-sql-modes,  Next: faqs-stored-procs,  Prev: faqs-storage-engines,  Up: faqs

B.3 MySQL 5.0 FAQ: Server SQL Mode
==================================

*Questions*
   * B.3.1: What are server SQL modes?

   * B.3.2: How many server SQL modes are there?

   * B.3.3: How do you determine the server SQL mode?

   * B.3.4: Is the mode dependent on the database or connection?

   * B.3.5: Can the rules for strict mode be extended?

   * B.3.6: Does strict mode impact performance?

   * B.3.7: What is the default server SQL mode when My SQL 5.0 is
     installed?

*Questions and Answers* *B.3.1: ** What are server SQL modes?  *

Server SQL modes define what SQL syntax MySQL should support and what
kind of data validation checks it should perform. This makes it easier
to use MySQL in different environments and to use MySQL together with
other database servers. The MySQL Server apply these modes individually
to different clients. For more information, see *Note server-sql-mode::.

*B.3.2: ** How many server SQL modes are there?  *

Each mode can be independently switched on and off. See *Note
server-sql-mode::, for a complete list of available modes.

*B.3.3: ** How do you determine the server SQL mode?  *

You can set the default SQL mode (for *Note `mysqld': mysqld.  startup)
with the `--sql-mode' option. Using the statement *Note `SET
[GLOBAL|SESSION] sql_mode='MODES'': set-option, you can change the
settings from within a connection, either locally to the connection, or
to take effect globally. You can retrieve the current mode by issuing a
`SELECT @@sql_mode' statement.

*B.3.4: ** Is the mode dependent on the database or connection?  *

A mode is not linked to a particular database. Modes can be set locally
to the session (connection), or globally for the server.  you can
change these settings using *Note `SET [GLOBAL|SESSION]
sql_mode='MODES'': set-option.

*B.3.5: ** Can the rules for strict mode be extended?  *

When we refer to _strict mode_, we mean a mode where at least one of
the modes `TRADITIONAL', `STRICT_TRANS_TABLES', or `STRICT_ALL_TABLES'
is enabled.  Options can be combined, so you can add restrictions to a
mode.  See *Note server-sql-mode::, for more information.

*B.3.6: ** Does strict mode impact performance?  *

The intensive validation of input data that some settings requires more
time than if the validation is not done. While the performance impact
is not that great, if you do not require such validation (perhaps your
application already handles all of this), then MySQL gives you the
option of leaving strict mode disabled. However--if you do require
it--strict mode can provide such validation.

*B.3.7: ** What is the default server SQL mode when My SQL 5.0 is
installed?  *

By default, no special modes are enabled. See *Note server-sql-mode::,
for information about all available modes and MySQL's default behavior.


File: manual.info,  Node: faqs-stored-procs,  Next: faqs-triggers,  Prev: faqs-sql-modes,  Up: faqs

B.4 MySQL 5.0 FAQ: Stored Procedures and Functions
==================================================

*Questions*
   * B.4.1: Does MySQL 5.0 support stored procedures and functions?

   * B.4.2: Where can I find documentation for MySQL stored procedures
     and stored functions?

   * B.4.3: Is there a discussion forum for MySQL stored procedures?

   * B.4.4: Where can I find the ANSI SQL 2003 specification for stored
     procedures?

   * B.4.5: How do you manage stored routines?

   * B.4.6: Is there a way to view all stored procedures and stored
     functions in a given database?

   * B.4.7: Where are stored procedures stored?

   * B.4.8: Is it possible to group stored procedures or stored
     functions into packages?

   * B.4.9: Can a stored procedure call another stored procedure?

   * B.4.10: Can a stored procedure call a trigger?

   * B.4.11: Can a stored procedure access tables?

   * B.4.12: Do stored procedures have a statement for raising
     application errors?

   * B.4.13: Do stored procedures provide exception handling?

   * B.4.14: Can MySQL 5.0 stored routines return result sets?

   * B.4.15: Is `WITH RECOMPILE' supported for stored procedures?

   * B.4.16: Is there a MySQL equivalent to using `mod_plsql' as a
     gateway on Apache to talk directly to a stored procedure in the
     database?

   * B.4.17: Can I pass an array as input to a stored procedure?

   * B.4.18: Can I pass a cursor as an `IN' parameter to a stored
     procedure?

   * B.4.19: Can I return a cursor as an `OUT' parameter from a stored
     procedure?

   * B.4.20: Can I print out a variable's value within a stored routine
     for debugging purposes?

   * B.4.21: Can I commit or roll back transactions inside a stored
     procedure?

   * B.4.22: Do MySQL 5.0 stored procedures and functions work with
     replication?

   * B.4.23: Are stored procedures and functions created on a master
     server replicated to a slave?

   * B.4.24: How are actions that take place inside stored procedures
     and functions replicated?

   * B.4.25: Are there special security requirements for using stored
     procedures and functions together with replication?

   * B.4.26: What limitations exist for replicating stored procedure and
     function actions?

   * B.4.27: Do the preceding limitations affect MySQL's ability to do
     point-in-time recovery?

   * B.4.28: What is being done to correct the aforementioned
     limitations?

*Questions and Answers* *B.4.1: ** Does MySQL 5.0 support stored
procedures and functions?  *

Yes. MySQL 5.0 supports two types of stored routines--stored procedures
and stored functions.

*B.4.2: ** Where can I find documentation for MySQL stored procedures
and stored functions?  *

See *Note stored-routines::.

*B.4.3: ** Is there a discussion forum for MySQL stored procedures?  *

Yes. See http://forums.mysql.com/list.php?98
(http://forums.mysql.com/list.php?98).

*B.4.4: ** Where can I find the ANSI SQL 2003 specification for stored
procedures?  *

Unfortunately, the official specifications are not freely available
(ANSI makes them available for purchase). However, there are
books--such as `SQL-99 Complete, Really' by Peter Gulutzan and Trudy
Pelzer--which give a comprehensive overview of the standard, including
coverage of stored procedures.

*B.4.5: ** How do you manage stored routines?  *

It is always good practice to use a clear naming scheme for your stored
routines. You can manage stored procedures with `CREATE
[FUNCTION|PROCEDURE]', `ALTER [FUNCTION|PROCEDURE]', `DROP
[FUNCTION|PROCEDURE]', and `SHOW CREATE [FUNCTION|PROCEDURE]'. You can
obtain information about existing stored procedures using the *Note
`ROUTINES': routines-table. table in the `INFORMATION_SCHEMA' database
(see *Note routines-table::).

*B.4.6: ** Is there a way to view all stored procedures and stored
functions in a given database?  *

Yes. For a database named DBNAME, use this query on the *Note
`INFORMATION_SCHEMA.ROUTINES': routines-table. table:

     SELECT ROUTINE_TYPE, ROUTINE_NAME
         FROM INFORMATION_SCHEMA.ROUTINES
         WHERE ROUTINE_SCHEMA='DBNAME';

For more information, see *Note routines-table::.

The body of a stored routine can be viewed using *Note `SHOW CREATE
FUNCTION': show-create-function. (for a stored function) or *Note `SHOW
CREATE PROCEDURE': show-create-procedure. (for a stored procedure). See
*Note show-create-procedure::, for more information.

*B.4.7: ** Where are stored procedures stored?  *

In the `proc' table of the `mysql' system database. However, you should
not access the tables in the system database directly. Instead, use
*Note `SHOW CREATE FUNCTION': show-create-function. to obtain
information about stored functions, and *Note `SHOW CREATE PROCEDURE':
show-create-procedure. to obtain information about stored procedures.
See *Note show-create-procedure::, for more information about these
statements.

You can also query the *Note `ROUTINES': routines-table.  table in the
`INFORMATION_SCHEMA' database--see *Note routines-table::, for
information about this table.

*B.4.8: ** Is it possible to group stored procedures or stored functions
into packages?  *

No. This is not supported in MySQL 5.0.

*B.4.9: ** Can a stored procedure call another stored procedure?  *

Yes.

*B.4.10: ** Can a stored procedure call a trigger?  *

A stored procedure can execute an SQL statement, such as an *Note
`UPDATE': update, that causes a trigger to activate.

*B.4.11: ** Can a stored procedure access tables?  *

Yes. A stored procedure can access one or more tables as required.

*B.4.12: ** Do stored procedures have a statement for raising
application errors?  *

Not in MySQL 5.0. The SQL standard `SIGNAL' and `RESIGNAL' statements
are implemented in MySQL 5.5.

*B.4.13: ** Do stored procedures provide exception handling?  *

MySQL implements *Note `HANDLER': handler.  definitions according to
the SQL standard. See *Note declare-handler::, for details.

*B.4.14: ** Can MySQL 5.0 stored routines return result sets?  *

_Stored procedures_ can, but stored functions cannot. If you perform an
ordinary *Note `SELECT': select. inside a stored procedure, the result
set is returned directly to the client. You need to use the MySQL 4.1
(or above) client/server protocol for this to work. This means
that--for instance--in PHP, you need to use the `mysqli' extension
rather than the old `mysql' extension.

*B.4.15: ** Is `WITH RECOMPILE' supported for stored procedures?  *

Not in MySQL 5.0.

*B.4.16: ** Is there a MySQL equivalent to using `mod_plsql' as a
gateway on Apache to talk directly to a stored procedure in the
database?  *

There is no equivalent in MySQL 5.0.

*B.4.17: ** Can I pass an array as input to a stored procedure?  *

Not in MySQL 5.0.

*B.4.18: ** Can I pass a cursor as an `IN' parameter to a stored
procedure?  *

In MySQL 5.0, cursors are available inside stored procedures only.

*B.4.19: ** Can I return a cursor as an `OUT' parameter from a stored
procedure?  *

In MySQL 5.0, cursors are available inside stored procedures only.
However, if you do not open a cursor on a *Note `SELECT': select, the
result will be sent directly to the client. You can also `SELECT INTO'
variables. See *Note select::.

*B.4.20: ** Can I print out a variable's value within a stored routine
for debugging purposes?  *

Yes, you can do this in a _stored procedure_, but not in a stored
function. If you perform an ordinary *Note `SELECT': select. inside a
stored procedure, the result set is returned directly to the client.
You will need to use the MySQL 4.1 (or above) client/server protocol
for this to work. This means that--for instance--in PHP, you need to
use the `mysqli' extension rather than the old `mysql' extension.

*B.4.21: ** Can I commit or roll back transactions inside a stored
procedure?  *

Yes. However, you cannot perform transactional operations within a
stored function.

*B.4.22: ** Do MySQL 5.0 stored procedures and functions work with
replication?  *

Yes, standard actions carried out in stored procedures and functions
are replicated from a master MySQL server to a slave server. There are
a few limitations that are described in detail in *Note
stored-programs-logging::.

*B.4.23: ** Are stored procedures and functions created on a master
server replicated to a slave?  *

Yes, creation of stored procedures and functions carried out through
normal DDL statements on a master server are replicated to a slave, so
the objects will exist on both servers.  `ALTER' and `DROP' statements
for stored procedures and functions are also replicated.

*B.4.24: ** How are actions that take place inside stored procedures and
functions replicated?  *

MySQL records each DML event that occurs in a stored procedure and
replicates those individual actions to a slave server. The actual calls
made to execute stored procedures are not replicated.

Stored functions that change data are logged as function invocations,
not as the DML events that occur inside each function.

*B.4.25: ** Are there special security requirements for using stored
procedures and functions together with replication?  *

Yes. Because a slave server has authority to execute any statement read
from a master's binary log, special security constraints exist for
using stored functions with replication.  If replication or binary
logging in general (for the purpose of point-in-time recovery) is
active, then MySQL DBAs have two security options open to them:

  1. Any user wishing to create stored functions must be granted the
     `SUPER' privilege.

  2. Alternatively, a DBA can set the `log_bin_trust_function_creators'
     system variable to 1, which enables anyone with the standard
     `CREATE ROUTINE' privilege to create stored functions.

*B.4.26: ** What limitations exist for replicating stored procedure and
function actions?  *

Nondeterministic (random) or time-based actions embedded in stored
procedures may not replicate properly. By their very nature, randomly
produced results are not predictable and cannot be exactly reproduced,
and therefore, random actions replicated to a slave will not mirror
those performed on a master. Note that declaring stored functions to be
`DETERMINISTIC' or setting the `log_bin_trust_function_creators' system
variable to 0 will not allow random-valued operations to be invoked.

In addition, time-based actions cannot be reproduced on a slave because
the timing of such actions in a stored procedure is not reproducible
through the binary log used for replication. It records only DML events
and does not factor in timing constraints.

Finally, nontransactional tables for which errors occur during large
DML actions (such as bulk inserts) may experience replication issues in
that a master may be partially updated from DML activity, but no
updates are done to the slave because of the errors that occurred. A
workaround is for a function's DML actions to be carried out with the
`IGNORE' keyword so that updates on the master that cause errors are
ignored and updates that do not cause errors are replicated to the
slave.

*B.4.27: ** Do the preceding limitations affect MySQL's ability to do
point-in-time recovery?  *

The same limitations that affect replication do affect point-in-time
recovery.

*B.4.28: ** What is being done to correct the aforementioned
limitations?  *

MySQL 5.1 implements _row-based replication_, which resolves the
limitations mentioned earlier.

We do not plan to backport row-based replication to MySQL 5.0.  For
additional information, see Replication Formats
(http://dev.mysql.com/doc/refman/5.1/en/replication-formats.html), in
the `MySQL 5.1 Manual'.


File: manual.info,  Node: faqs-triggers,  Next: faqs-views,  Prev: faqs-stored-procs,  Up: faqs

B.5 MySQL 5.0 FAQ: Triggers
===========================

*Questions*
   * B.5.1: Where can I find the documentation for MySQL 5.0 triggers?

   * B.5.2: Is there a discussion forum for MySQL Triggers?

   * B.5.3: Does MySQL 5.0 have statement-level or row-level triggers?

   * B.5.4: Are there any default triggers?

   * B.5.5: How are triggers managed in MySQL?

   * B.5.6: Is there a way to view all triggers in a given database?

   * B.5.7: Where are triggers stored?

   * B.5.8: Can a trigger call a stored procedure?

   * B.5.9: Can triggers access tables?

   * B.5.10: Can triggers call an external application through a UDF?

   * B.5.11: Is it possible for a trigger to update tables on a remote
     server?

   * B.5.12: Do triggers work with replication?

   * B.5.13: How are actions carried out through triggers on a master
     replicated to a slave?

*Questions and Answers* *B.5.1: ** Where can I find the documentation
for MySQL 5.0 triggers?  *

See *Note triggers::.

*B.5.2: ** Is there a discussion forum for MySQL Triggers?  *

Yes. It is available at `http://forums.mysql.com/list.php?99'.

*B.5.3: ** Does MySQL 5.0 have statement-level or row-level triggers?  *

In MySQL 5.0, all triggers are `FOR EACH ROW'--that is, the trigger is
activated for each row that is inserted, updated, or deleted. MySQL 5.0
does not support triggers using `FOR EACH STATEMENT'.

*B.5.4: ** Are there any default triggers?  *

Not explicitly. MySQL does have specific special behavior for some
*Note `TIMESTAMP': datetime. columns, as well as for columns which are
defined using `AUTO_INCREMENT'.

*B.5.5: ** How are triggers managed in MySQL?  *

In MySQL 5.0, triggers can be created using the *Note `CREATE TRIGGER':
create-trigger. statement, and dropped using *Note `DROP TRIGGER':
drop-trigger. See *Note create-trigger::, and *Note drop-trigger::, for
more about these statements.

Information about triggers can be obtained by querying the *Note
`INFORMATION_SCHEMA.TRIGGERS': triggers-table. table.  See *Note
triggers-table::.

*B.5.6: ** Is there a way to view all triggers in a given database?  *

Yes. You can obtain a listing of all triggers defined on database
`dbname' using a query on the *Note `INFORMATION_SCHEMA.TRIGGERS':
triggers-table. table such as the one shown here:

     SELECT TRIGGER_NAME, EVENT_MANIPULATION, EVENT_OBJECT_TABLE, ACTION_STATEMENT
         FROM INFORMATION_SCHEMA.TRIGGERS
         WHERE TRIGGER_SCHEMA='DBNAME';

For more information about this table, see *Note triggers-table::.

You can also use the *Note `SHOW TRIGGERS': show-triggers. statement,
which is specific to MySQL. See *Note show-triggers::.

*B.5.7: ** Where are triggers stored?  *

Triggers for a table are currently stored in `.TRG' files, with one
such file one per table.

*B.5.8: ** Can a trigger call a stored procedure?  *

Yes.

*B.5.9: ** Can triggers access tables?  *

A trigger can access both old and new data in its own table. A trigger
can also affect other tables, but it is not permitted to modify a table
that is already being used (for reading or writing) by the statement
that invoked the function or trigger.  (Before MySQL 5.0.10, a trigger
cannot modify other tables.)

*B.5.10: ** Can triggers call an external application through a UDF?  *

Yes. For example, a trigger could invoke the `sys_exec()' UDF available
at MySQL Forge here:
`http://forge.mysql.com/projects/project.php?id=211'

*B.5.11: ** Is it possible for a trigger to update tables on a remote
server?  *

Yes. A table on a remote server could be updated using the `FEDERATED'
storage engine. (See *Note federated-storage-engine::).

*B.5.12: ** Do triggers work with replication?  *

Triggers and replication in MySQL 5.0 work in the same way as in most
other database systems: Actions carried out through triggers on a
master are not replicated to a slave server. Instead, triggers that
exist on tables that reside on a MySQL master server need to be created
on the corresponding tables on any MySQL slave servers so that the
triggers activate on the slaves as well as the master.

For more information, see *Note replication-features-triggers::.

*B.5.13: ** How are actions carried out through triggers on a master
replicated to a slave?  *

First, the triggers that exist on a master must be re-created on the
slave server. Once this is done, the replication flow works as any
other standard DML statement that participates in replication. For
example, consider a table `EMP' that has an `AFTER' insert trigger,
which exists on a master MySQL server. The same `EMP' table and `AFTER'
insert trigger exist on the slave server as well. The replication flow
would be:

  1. An *Note `INSERT': insert. statement is made to `EMP'.

  2. The `AFTER' trigger on `EMP' activates.

  3. The *Note `INSERT': insert. statement is written to the binary log.

  4. The replication slave picks up the *Note `INSERT': insert.
     statement to `EMP' and executes it.

  5. The `AFTER' trigger on `EMP' that exists on the slave activates.

For more information, see *Note replication-features-triggers::.


File: manual.info,  Node: faqs-views,  Next: faqs-information-schema,  Prev: faqs-triggers,  Up: faqs

B.6 MySQL 5.0 FAQ: Views
========================

*Questions*
   * B.6.1: Where can I find documentation covering MySQL Views?

   * B.6.2: Is there a discussion forum for MySQL Views?

   * B.6.3: What happens to a view if an underlying table is dropped or
     renamed?

   * B.6.4: Does MySQL 5.0 have table snapshots?

   * B.6.5: Does MySQL 5.0 have materialized views?

   * B.6.6: Can you insert into views that are based on joins?

*Questions and Answers* *B.6.1: ** Where can I find documentation
covering MySQL Views?  *

See *Note views::.

*B.6.2: ** Is there a discussion forum for MySQL Views?  *

Yes. See http://forums.mysql.com/list.php?100
(http://forums.mysql.com/list.php?100)

*B.6.3: ** What happens to a view if an underlying table is dropped or
renamed?  *

After a view has been created, it is possible to drop or alter a table
or view to which the definition refers. To check a view definition for
problems of this kind, use the *Note `CHECK TABLE': check-table.
statement. (See *Note check-table::.)

*B.6.4: ** Does MySQL 5.0 have table snapshots?  *

No.

*B.6.5: ** Does MySQL 5.0 have materialized views?  *

No.

*B.6.6: ** Can you insert into views that are based on joins?  *

It is possible, provided that your *Note `INSERT': insert. statement
has a column list that makes it clear there is only one table involved.

You _cannot_ insert into multiple tables with a single insert on a view.


File: manual.info,  Node: faqs-information-schema,  Next: faqs-migration,  Prev: faqs-views,  Up: faqs

B.7 MySQL 5.0 FAQ: `INFORMATION_SCHEMA'
=======================================

*Questions*
   * B.7.1: Where can I find documentation for the MySQL
     `INFORMATION_SCHEMA' database?

   * B.7.2: Is there a discussion forum for `INFORMATION_SCHEMA'?

   * B.7.3: Where can I find the ANSI SQL 2003 specification for
     `INFORMATION_SCHEMA'?

   * B.7.4: What is the difference between the Oracle Data Dictionary
     and MySQL's `INFORMATION_SCHEMA'?

   * B.7.5: Can I add to or otherwise modify the tables found in the
     `INFORMATION_SCHEMA' database?

*Questions and Answers* *B.7.1: ** Where can I find documentation for
the MySQL `INFORMATION_SCHEMA' database?  *

See *Note information-schema::

*B.7.2: ** Is there a discussion forum for `INFORMATION_SCHEMA'?  *

See http://forums.mysql.com/list.php?101
(http://forums.mysql.com/list.php?101).

*B.7.3: ** Where can I find the ANSI SQL 2003 specification for
`INFORMATION_SCHEMA'?  *

Unfortunately, the official specifications are not freely available.
(ANSI makes them available for purchase.) However, there are books
available--such as `SQL-99 Complete, Really' by Peter Gulutzan and Trudy
Pelzer--which give a comprehensive overview of the standard, including
`INFORMATION_SCHEMA'.

*B.7.4: ** What is the difference between the Oracle Data Dictionary and
MySQL's `INFORMATION_SCHEMA'?  *

Both Oracle and MySQL provide metadata in tables. However, Oracle and
MySQL use different table names and column names.  MySQL's
implementation is more similar to those found in DB2 and SQL Server,
which also support `INFORMATION_SCHEMA' as defined in the SQL standard.

*B.7.5: ** Can I add to or otherwise modify the tables found in the
`INFORMATION_SCHEMA' database?  *

No. Since applications may rely on a certain standard structure, this
should not be modified. For this reason, _we cannot support bugs or
other issues which result from modifying `INFORMATION_SCHEMA' tables or
data_.


File: manual.info,  Node: faqs-migration,  Next: faqs-security,  Prev: faqs-information-schema,  Up: faqs

B.8 MySQL 5.0 FAQ: Migration
============================

*Questions*
   * B.8.1: Where can I find information on how to migrate from MySQL
     4.1 to MySQL 5.0?

   * B.8.2: How has storage engine (table type) support changed in MySQL
     5.0 from previous versions?

*Questions and Answers* *B.8.1: ** Where can I find information on how
to migrate from MySQL 4.1 to MySQL 5.0?  *

For detailed upgrade information, see *Note upgrading::. Do not skip a
major version when upgrading, but rather complete the process in steps,
upgrading from one major version to the next in each step. This may seem
more complicated, but it will you save time and trouble--if you
encounter problems during the upgrade, their origin will be easier to
identify, either by you or--if you have a MySQL Enterprise
subscription--by MySQL support.

*B.8.2: ** How has storage engine (table type) support changed in MySQL
5.0 from previous versions?  *

Storage engine support has changed as follows:

   * Support for `ISAM' tables was removed in MySQL 5.0 and you should
     now use the `MyISAM' storage engine in place of `ISAM'. To convert
     a table TBLNAME from `ISAM' to `MyISAM', simply issue a statement
     such as this one:

          ALTER TABLE TBLNAME ENGINE=MYISAM;

   * Internal `RAID' for `MyISAM' tables was also removed in MySQL 5.0.
     This was formerly used to allow large tables in file systems that
     did not support file sizes greater than 2GB.  All modern file
     systems allow for larger tables; in addition, there are now other
     solutions such as `MERGE' tables and views.

   * The *Note `VARCHAR': char. column type now retains trailing spaces
     in all storage engines.

   * `MEMORY' tables (formerly known as `HEAP' tables) can also contain
     *Note `VARCHAR': char. columns.


File: manual.info,  Node: faqs-security,  Next: faqs-mysql-cluster,  Prev: faqs-migration,  Up: faqs

B.9 MySQL 5.0 FAQ: Security
===========================

*Questions*
   * B.9.1: Where can I find documentation that addresses security
     issues for MySQL?

   * B.9.2: Does MySQL 5.0 have native support for SSL?

   * B.9.3: Is SSL support be built into MySQL binaries, or must I
     recompile the binary myself to enable it?

   * B.9.4: Does MySQL 5.0 have built-in authentication against LDAP
     directories?

   * B.9.5: Does MySQL 5.0 include support for Roles Based Access
     Control (RBAC)?

*Questions and Answers* *B.9.1: ** Where can I find documentation that
addresses security issues for MySQL?  *

The best place to start is *Note security::.

Other portions of the MySQL Documentation which you may find useful
with regard to specific security concerns include the following:

   * *Note security-guidelines::.

   * *Note security-against-attack::.

   * *Note resetting-permissions::.

   * *Note changing-mysql-user::.

   * *Note udf-security::.

   * *Note privileges-options::.

   * *Note load-data-local::.

   * *Note postinstallation::.

   * *Note secure-basics::.

*B.9.2: ** Does MySQL 5.0 have native support for SSL?  *

Most 5.0 binaries have support for SSL connections between the client
and server. We can't currently build with the new YaSSL library
everywhere, as it is still quite new and does not compile on all
platforms yet. See *Note secure-connections::.

You can also tunnel a connection using SSH, if (for example) the client
application doesn't support SSL connections. For an example, see *Note
windows-and-ssh::.

*B.9.3: ** Is SSL support be built into MySQL binaries, or must I
recompile the binary myself to enable it?  *

Most 5.0 binaries have SSL enabled for client/server connections that
are secured, authenticated, or both. However, the YaSSL library
currently does not compile on all platforms. See *Note
secure-connections::, for a complete listing of supported and
unsupported platforms.

*B.9.4: ** Does MySQL 5.0 have built-in authentication against LDAP
directories?  *

Not at this time.

*B.9.5: ** Does MySQL 5.0 include support for Roles Based Access
Control (RBAC)?  *

Not at this time.


File: manual.info,  Node: faqs-mysql-cluster,  Next: faqs-cjk,  Prev: faqs-security,  Up: faqs

B.10 MySQL 5.0 FAQ: MySQL Cluster
=================================

In the following section, we answer questions that are frequently asked
about MySQL Cluster and the *Note `NDBCLUSTER': mysql-cluster. storage
engine.

*Questions*
   * B.10.1: Which versions of the MySQL software support Cluster? Do I
     have to compile from source?

   * B.10.2: What do `NDB' and `NDBCLUSTER' mean?

   * B.10.3: What is the difference between using MySQL Cluster _vs_
     using MySQL replication?

   * B.10.4: Do I need to do any special networking to run MySQL
     Cluster? How do computers in a cluster communicate?

   * B.10.5: How many computers do I need to run a MySQL Cluster, and
     why?

   * B.10.6: What do the different computers do in a MySQL Cluster?

   * B.10.7: When I run the `SHOW' command in the MySQL Cluster
     management client, I see a line of output that looks like this:

          id=2    @10.100.10.32  (Version: 5.0.95, Nodegroup: 0, Master)

     What is a `master node', and what does it do? How do I configure a
     node so that it is the master?

   * B.10.8: With which operating systems can I use Cluster?

   * B.10.9: What are the hardware requirements for running MySQL
     Cluster?

   * B.10.10: How much RAM do I need to use MySQL Cluster? Is it
     possible to use disk memory at all?

   * B.10.11: What file systems can I use with MySQL Cluster? What about
     network file systems or network shares?

   * B.10.12: Can I run MySQL Cluster nodes inside virtual machines
     (such as those created by VMWare, Parallels, or Xen)?

   * B.10.13: I am trying to populate a MySQL Cluster database. The
     loading process terminates prematurely and I get an error message
     like this one:

     ``ERROR 1114: The table 'my_cluster_table' is full''

     Why is this happening?

   * B.10.14: MySQL Cluster uses TCP/IP. Does this mean that I can run
     it over the Internet, with one or more nodes in remote locations?

   * B.10.15: Do I have to learn a new programming or query language to
     use MySQL Cluster?

   * B.10.16: How do I find out what an error or warning message means
     when using MySQL Cluster?

   * B.10.17: Is MySQL Cluster transaction-safe? What isolation levels
     are supported?

   * B.10.18: What storage engines are supported by MySQL Cluster?

   * B.10.19: In the event of a catastrophic failure--say, for instance,
     the whole city loses power _and_ my UPS fails--would I lose all my
     data?

   * B.10.20: Is it possible to use `FULLTEXT' indexes with MySQL
     Cluster?

   * B.10.21: Can I run multiple nodes on a single computer?

   * B.10.22: Can I add data nodes to a MySQL Cluster without
     restarting it?

   * B.10.23: Are there any limitations that I should be aware of when
     using MySQL Cluster?

   * B.10.24: How do I import an existing MySQL database into a MySQL
     Cluster?

   * B.10.25: How do cluster nodes communicate with one another?

   * B.10.26: What is an _arbitrator_?

   * B.10.27: What data types are supported by MySQL Cluster?

   * B.10.28: How do I start and stop MySQL Cluster?

   * B.10.29: What happens to MySQL Cluster data when the cluster is
     shut down?

   * B.10.30: Is it a good idea to have more than one management node
     for a MySQL Cluster?

   * B.10.31: Can I mix different kinds of hardware and operating
     systems in one MySQL Cluster?

   * B.10.32: Can I run two data nodes on a single host? Two SQL nodes?

   * B.10.33: Can I use host names with MySQL Cluster?

   * B.10.34: How do I handle MySQL users in a MySQL Cluster having
     multiple MySQL servers?

   * B.10.35: How do I continue to send queries in the event that one
     of the SQL nodes fails?

   * B.10.36: How do I back up and restore a MySQL Cluster?

   * B.10.37: What is an `angel process'?

*Questions and Answers* *B.10.1: ** Which versions of the MySQL
software support Cluster? Do I have to compile from source?  *

MySQL Cluster is supported in all server binaries in the 5.0 release
series for operating systems on which MySQL Cluster is available. See
*Note mysqld::. You can determine whether your server has *Note `NDB':
mysql-cluster. support using either either of the statements `SHOW
VARIABLES LIKE 'have_%'' or *Note `SHOW ENGINES': show-engines.

Linux users should note that *Note `NDB': mysql-cluster. is _not_
included in the standard MySQL server RPMs. Beginning with MySQL 5.0.4,
there are separate RPM packages for the *Note `NDB': mysql-cluster.
storage engine and accompanying management and other tools; see the
*Note `NDB': mysql-cluster. RPM Downloads section of the MySQL 5.0
Downloads page for these. (Prior to 5.0.4, you had to use the `-max'
binaries supplied as `.tar.gz' archives. This is still possible, but is
not required, so you can use your Linux distribution's RPM manager if
you prefer.)

You can also obtain *Note `NDB': mysql-cluster. support by compiling
MySQL from source, but it is not necessary to do so simply to use MySQL
Cluster. To download the latest binary, RPM, or source distribution in
the MySQL 5.0 series, visit
`http://dev.mysql.com/downloads/mysql/5.0.html'.

However, you should use MySQL NDB Cluster NDB 6.3 or 7.0 for new
deployments, and if you are already using MySQL 5.0 with clustering
support, to upgrade to one of these MySQL Cluster release series. For
an overview of improvements made in MySQL Cluster NDB 6.3 and 7.0, see
MySQL Cluster Development in MySQL Cluster NDB 6.3
(http://dev.mysql.com/doc/refman/5.1/en/mysql-cluster-development-5-1-ndb-6-3.html),
and MySQL Cluster Development in MySQL Cluster NDB 7.0
(http://dev.mysql.com/doc/refman/5.1/en/mysql-cluster-development-5-1-ndb-7-0.html),
respectively.

*B.10.2: ** What do `NDB' and `NDBCLUSTER' mean?  *

`NDB' stands for `*N*etwork *D*ata*b*ase'.  *Note `NDB': mysql-cluster.
and *Note `NDBCLUSTER': mysql-cluster. are both names for the storage
engine that enables clustering support in MySQL. While our developers
prefer *Note `NDB': mysql-cluster, either name is correct; both names
appear in our documentation, and either name can be used in the
`ENGINE' option of a *Note `CREATE TABLE': create-table.  statement for
creating a MySQL Cluster table.

*B.10.3: ** What is the difference between using MySQL Cluster _vs_
using MySQL replication?  *

In traditional MySQL replication, a master MySQL server updates one or
more slaves. Transactions are committed sequentially, and a slow
transaction can cause the slave to lag behind the master.  This means
that if the master fails, it is possible that the slave might not have
recorded the last few transactions. If a transaction-safe engine such as
*Note `InnoDB': innodb-storage-engine. is being used, a transaction
will either be complete on the slave or not applied at all, but
replication does not guarantee that all data on the master and the
slave will be consistent at all times. In MySQL Cluster, all data nodes
are kept in synchrony, and a transaction committed by any one data node
is committed for all data nodes. In the event of a data node failure,
all remaining data nodes remain in a consistent state.

In short, whereas standard MySQL replication is _asynchronous_, MySQL
Cluster is _synchronous_.

We have implemented (asynchronous) replication for Cluster in MySQL 5.1
and later. _MySQL Cluster Replication_ (also sometimes known as
`geo-replication') includes the capability to replicate both between
two MySQL Clusters, and from a MySQL Cluster to a non-Cluster MySQL
server. However, we do _not_ plan to backport this functionality to
MySQL 5.0. See MySQL Cluster Replication
(http://dev.mysql.com/doc/refman/5.1/en/mysql-cluster-replication.html#mysql-cluster-replication).

*B.10.4: ** Do I need to do any special networking to run MySQL
Cluster? How do computers in a cluster communicate?  *

MySQL Cluster is intended to be used in a high-bandwidth environment,
with computers connecting using TCP/IP. Its performance depends
directly upon the connection speed between the cluster's computers. The
minimum connectivity requirements for MySQL Cluster include a typical
100-megabit Ethernet network or the equivalent. We recommend you use
gigabit Ethernet whenever available.

The faster SCI protocol is also supported, but requires special
hardware. See *Note mysql-cluster-interconnects::, for more information
about SCI.

*B.10.5: ** How many computers do I need to run a MySQL Cluster, and
why?  *

A minimum of three computers is required to run a viable cluster.
However, the minimum _recommended_ number of computers in a MySQL
Cluster is four: one each to run the management and SQL nodes, and two
computers to serve as data nodes. The purpose of the two data nodes is
to provide redundancy; the management node must run on a separate
machine to guarantee continued arbitration services in the event that
one of the data nodes fails.

To provide increased throughput and high availability, you should use
multiple SQL nodes (MySQL Servers connected to the cluster). It is also
possible (although not strictly necessary) to run multiple management
servers.

*B.10.6: ** What do the different computers do in a MySQL Cluster?  *

A MySQL Cluster has both a physical and logical organization, with
computers being the physical elements. The logical or functional
elements of a cluster are referred to as _nodes_, and a computer
housing a cluster node is sometimes referred to as a _cluster host_.
There are three types of nodes, each corresponding to a specific role
within the cluster. These are:

   * Management node

     This node provides management services for the cluster as a whole,
     including startup, shutdown, backups, and configuration data for
     the other nodes. The management node server is implemented as the
     application *Note `ndb_mgmd': mysql-cluster-programs-ndb-mgmd.;
     the management client used to control MySQL Cluster is *Note
     `ndb_mgm': mysql-cluster-programs-ndb-mgm. See *Note
     mysql-cluster-programs-ndb-mgmd::, and *Note
     mysql-cluster-programs-ndb-mgm::, for information about these
     programs.

   * Data node

     This type of node stores and replicates data. Data node
     functionality is handled by instances of the *Note `NDB':
     mysql-cluster. data node process *Note `ndbd':
     mysql-cluster-programs-ndbd. For more information, see *Note
     mysql-cluster-programs-ndbd::.

   * SQL node

     This is simply an instance of MySQL Server (*Note `mysqld':
     mysqld.) that is built with support for the *Note `NDBCLUSTER':
     mysql-cluster. storage engine and started with the `--ndb-cluster'
     option to enable the engine and the `--ndb-connectstring' option
     to enable it to connect to a MySQL Cluster management server. For
     more about these options, see *Note
     mysql-cluster-program-options-mysqld::.

     *Note*:

     An _API node_ is any application that makes direct use of Cluster
     data nodes for data storage and retrieval. An SQL node can thus be
     considered a type of API node that uses a MySQL Server to provide
     an SQL interface to the Cluster. You can write such applications
     (that do not depend on a MySQL Server) using the NDB API, which
     supplies a direct, object-oriented transaction and scanning
     interface to MySQL Cluster data; see MySQL Cluster API Overview:
     The NDB API
     (http://dev.mysql.com/doc/ndbapi/en/overview-ndb-api.html), for
     more information.

*B.10.7: ** When I run the `SHOW' command in the MySQL Cluster
management client, I see a line of output that looks like this: *
     id=2    @10.100.10.32  (Version: 5.0.95, Nodegroup: 0, Master)
* What is a `master node', and what does it do? How do I configure a
node so that it is the master?  *

The simplest answer is, `It's not something you can control, and it's
nothing that you need to worry about in any case, unless you're a
software engineer writing or analyzing the MySQL Cluster source code'.

If you don't find that answer satisfactory, here's a longer and more
technical version:

A number of mechanisms in MySQL Cluster require distributed
coordination among the data nodes. These distributed algorithms and
protocols include global checkpointing, DDL (schema) changes, and node
restart handling. To make this coordination simpler, the data nodes
`elect' one of their number to be a `master'. There is no user-facing
mechanism for influencing this selection, which is is completely
automatic; the fact that it _is_ automatic is a key part of MySQL
Cluster's internal architecture.

When a node acts as a master for any of these mechanisms, it is usually
the point of coordination for the activity, and the other nodes act as
`servants', carrying out their parts of the activity as directed by the
master. If the node acting as master fails, then the remaining nodes
elect a new master. Tasks in progress that were being coordinated by
the old master may either fail or be continued by the new master,
depending on the actual mechanism involved.

It is possible for some of these different mechanisms and protocols to
have different master nodes, but in general the same master is chosen
for all of them. The node indicated as the master in the output of
`SHOW' in the management client is actually the `DICT' master (see The
`DBDICT' Block
(http://dev.mysql.com/doc/ndbapi/en/ndb-internals-kernel-blocks-dbdict.html),
in the `MySQL Cluster API Developer Guide', for more information),
responsible for coordinating DDL and metadata activity.

MySQL Cluster is designed in such a way that the choice of master has
no discernable effect outside the cluster itself. For example, the
current master does not have significantly higher CPU or resource usage
than the other data nodes, and failure of the master should not have a
significantly different impact on the cluster than the failure of any
other data node.

*B.10.8: ** With which operating systems can I use Cluster?  *

MySQL Cluster is supported on most Unix-like operating systems,
including Linux, Mac OS X, and Solaris. Beginning with MySQL Cluster
NDB 7.1.3, MySQL Cluster is also supported in production on Microsoft
Windows operating systems.

*Important*:

We do not intend to provide any level of support on Windows for MySQL
Cluster in MySQL 5.0; you must use MySQL Cluster NDB 7.1.3 or later to
obtain GA-level support for MySQL Cluster in a Windows environment. See
MySQL Cluster Development in MySQL Cluster NDB 7.1
(http://dev.mysql.com/doc/refman/5.1/en/mysql-cluster-development-5-1-ndb-7-1.html),
for more information.

For more detailed information concerning the level of support which is
offered for MySQL Cluster on various operating system versions,
operating system distributions, and hardware platforms, please refer to
http://www.mysql.com/support/supportedplatforms/cluster.html .

*B.10.9: ** What are the hardware requirements for running MySQL
Cluster?  *

MySQL Cluster should run on any platform for which *Note `NDB':
mysql-cluster.-enabled binaries are available.  For data nodes and API
nodes, faster CPUs and more memory are likely to improve performance,
and 64-bit CPUs are likely to be more effective than 32-bit processors.
There must be sufficient memory on machines used for data nodes to hold
each node's share of the database (see _How much RAM do I Need?_ for
more information). For a computer which is used only for running the
MySQL Cluster management server, the requirements are minimal; a common
desktop PC (or the equivalent) is generally sufficient for this task.
Nodes can communicate through the standard TCP/IP network and hardware.
They can also use the high-speed SCI protocol; however, special
networking hardware and software are required to use SCI (see *Note
mysql-cluster-interconnects::).

*B.10.10: ** How much RAM do I need to use MySQL Cluster? Is it
possible to use disk memory at all?  *

In MySQL 5.0, Cluster is in-memory only. This means that all table data
(including indexes) is stored in RAM.  Therefore, if your data takes up
1 GB of space and you want to replicate it once in the cluster, you
need 2 GB of memory to do so (1 GB per replica). This is in addition to
the memory required by the operating system and any applications
running on the cluster computers.

If a data node's memory usage exceeds what is available in RAM, then
the system will attempt to use swap space up to the limit set for
`DataMemory'. However, this will at best result in severely degraded
performance, and may cause the node to be dropped due to slow response
time (missed heartbeats). We do not recommend on relying on disk
swapping in a production environment for this reason. In any case, once
the `DataMemory' limit is reached, any operations requiring additional
memory (such as inserts) will fail.

We have implemented disk data storage for MySQL Cluster in MySQL 5.1
and later but we have no plans to add this capability in MySQL 5.0. See
MySQL Cluster Disk Data Tables
(http://dev.mysql.com/doc/refman/5.1/en/mysql-cluster-disk-data.html),
for more information.

You can use the following formula for obtaining a rough estimate of how
much RAM is needed for each data node in the cluster:

     (SizeofDatabase x NumberOfReplicas x 1.1 ) / NumberOfDataNodes

To calculate the memory requirements more exactly requires determining,
for each table in the cluster database, the storage space required per
row (see *Note storage-requirements::, for details), and multiplying
this by the number of rows. You must also remember to account for any
column indexes as follows:

   * Each primary key or hash index created for an *Note `NDBCLUSTER':
     mysql-cluster. table requires 21-25 bytes per record. These
     indexes use `IndexMemory'.

   * Each ordered index requires 10 bytes storage per record, using
     `DataMemory'.

   * Creating a primary key or unique index also creates an ordered
     index, unless this index is created with `USING HASH'. In other
     words:

        * A primary key or unique index on a Cluster table normally
          takes up 31 to 35 bytes per record.

        * However, if the primary key or unique index is created with
          `USING HASH', then it requires only 21 to 25 bytes per record.

Note that creating MySQL Cluster tables with `USING HASH' for all
primary keys and unique indexes will generally cause table updates to
run more quickly--in some cases by a much as 20 to 30 percent faster
than updates on tables where `USING HASH' was not used in creating
primary and unique keys. This is due to the fact that less memory is
required (because no ordered indexes are created), and that less CPU
must be utilized (because fewer indexes must be read and possibly
updated). However, it also means that queries that could otherwise use
range scans must be satisfied by other means, which can result in
slower selects.

When calculating Cluster memory requirements, you may find useful the
*Note `ndb_size.pl': mysql-cluster-programs-ndb-size-pl. utility which
is available in recent MySQL 5.0 releases. This Perl script connects to
a current (non-Cluster) MySQL database and creates a report on how much
space that database would require if it used the *Note `NDBCLUSTER':
mysql-cluster. storage engine. For more information, see *Note
mysql-cluster-programs-ndb-size-pl::.

It is especially important to keep in mind that _every MySQL Cluster
table must have a primary key_. The *Note `NDB': mysql-cluster. storage
engine creates a primary key automatically if none is defined; this
primary key is created without `USING HASH'.

There is no easy way to determine exactly how much memory is being used
for storage of Cluster indexes at any given time; however, warnings are
written to the Cluster log when 80% of available `DataMemory' or
`IndexMemory' is in use, and again when use reaches 85%, 90%, and so on.

*B.10.11: ** What file systems can I use with MySQL Cluster? What about
network file systems or network shares?  *

Generally, any file system that is native to the host operating system
should work well with MySQL Cluster. If you find that a given file
system works particularly well (or not so especially well) with MySQL
Cluster, we invite you to discuss your findings in the MySQL Cluster
Forums (http://forums.mysql.com/list.php?25).

We do not test MySQL Cluster with `FAT' or `VFAT' file systems on
Linux. Because of this, and due to the fact that these are not very
useful for any purpose other than sharing disk partitions between Linux
and Windows operating systems on multi-boot computers, we do not
recommend their use with MySQL Cluster.

MySQL Cluster is implemented as a shared-nothing solution; the idea
behind this is that the failure of a single piece of hardware should
not cause the failure of multiple cluster nodes, or possibly even the
failure of the cluster as a whole. For this reason, the use of network
shares or network file systems is not supported for MySQL Cluster. This
also applies to shared storage devices such as SANs.

*B.10.12: ** Can I run MySQL Cluster nodes inside virtual machines
(such as those created by VMWare, Parallels, or Xen)?  *

This is possible but not recommended for a production environment.

We have found that running MySQL Cluster processes inside a virtual
machine can give rise to issues with timing and disk subsystems that
have a strong negative impact on the operation of the cluster. The
behavior of the cluster is often unpredictable in these cases.

If an issue can be reproduced outside the virtual environment, then we
may be able to provide assistance. Otherwise, we cannot support it at
this time.

*B.10.13: ** I am trying to populate a MySQL Cluster database. The
loading process terminates prematurely and I get an error message like
this one: ** ``ERROR 1114: The table 'my_cluster_table' is full'' **
Why is this happening?  *

The cause is very likely to be that your setup does not provide
sufficient RAM for all table data and all indexes, _including the
primary key required by the *Note `NDB': mysql-cluster. storage engine
and automatically created in the event that the table definition does
not include the definition of a primary key_.

It is also worth noting that all data nodes should have the same amount
of RAM, since no data node in a cluster can use more memory than the
least amount available to any individual data node. For example, if
there are four computers hosting Cluster data nodes, and three of these
have 3GB of RAM available to store Cluster data while the remaining
data node has only 1GB RAM, then each data node can devote at most 1GB
to MySQL Cluster data and indexes.

*B.10.14: ** MySQL Cluster uses TCP/IP. Does this mean that I can run
it over the Internet, with one or more nodes in remote locations?  *

It is _very_ unlikely that a cluster would perform reliably under such
conditions, as MySQL Cluster was designed and implemented with the
assumption that it would be run under conditions guaranteeing dedicated
high-speed connectivity such as that found in a LAN setting using 100
Mbps or gigabit Ethernet--preferably the latter. We neither test nor
warrant its performance using anything slower than this.

Also, it is extremely important to keep in mind that communications
between the nodes in a MySQL Cluster are not secure; they are neither
encrypted nor safeguarded by any other protective mechanism. The most
secure configuration for a cluster is in a private network behind a
firewall, with no direct access to any Cluster data or management nodes
from outside. (For SQL nodes, you should take the same precautions as
you would with any other instance of the MySQL server.) For more
information, see *Note mysql-cluster-security::.

*B.10.15: ** Do I have to learn a new programming or query language to
use MySQL Cluster?  *

_No_. Although some specialized commands are used to manage and
configure the cluster itself, only standard (My)SQL statements are
required for the following operations:

   * Creating, altering, and dropping tables

   * Inserting, updating, and deleting table data

   * Creating, changing, and dropping primary and unique indexes

Some specialized configuration parameters and files are required to set
up a MySQL Cluster--see *Note mysql-cluster-config-file::, for
information about these.

A few simple commands are used in the MySQL Cluster management client
(*Note `ndb_mgm': mysql-cluster-programs-ndb-mgm.) for tasks such as
starting and stopping cluster nodes. See *Note
mysql-cluster-mgm-client-commands::.

*B.10.16: ** How do I find out what an error or warning message means
when using MySQL Cluster?  *

There are two ways in which this can be done:

   * From within the *Note `mysql': mysql. client, use `SHOW ERRORS' or
     `SHOW WARNINGS' immediately upon being notified of the error or
     warning condition.

   * From a system shell prompt, use *Note `perror --ndb ERROR_CODE':
     perror.

*B.10.17: ** Is MySQL Cluster transaction-safe? What isolation levels
are supported?  *

_Yes_. For tables created with the *Note `NDB': mysql-cluster. storage
engine, transactions are supported. Currently, MySQL Cluster supports
only the `READ COMMITTED' transaction isolation level.

*B.10.18: ** What storage engines are supported by MySQL Cluster?  *

Clustering with MySQL is supported only by the *Note `NDB':
mysql-cluster. storage engine. That is, in order for a table to be
shared between nodes in a MySQL Cluster, the table must be created
using `ENGINE=NDB' (or the equivalent option `ENGINE=NDBCLUSTER').

It is possible to create tables using other storage engines (such as
*Note `MyISAM': myisam-storage-engine. or *Note `InnoDB':
innodb-storage-engine.) on a MySQL server being used with a MySQL
Cluster, but these non-*Note `NDB': mysql-cluster. tables do _not_
participate in clustering; each such table is strictly local to the
individual MySQL server instance on which it is created.

*B.10.19: ** In the event of a catastrophic failure--say, for instance,
the whole city loses power _and_ my UPS fails--would I lose all my data?
*

All committed transactions are logged. Therefore, although it is
possible that some data could be lost in the event of a catastrophe,
this should be quite limited. Data loss can be further reduced by
minimizing the number of operations per transaction. (It is not a good
idea to perform large numbers of operations per transaction in any
case.)

*B.10.20: ** Is it possible to use `FULLTEXT' indexes with MySQL
Cluster?  *

`FULLTEXT' indexing is not supported by any storage engine other than
*Note `MyISAM': myisam-storage-engine.  We are working to add this
capability to MySQL Cluster tables in a future release.

*B.10.21: ** Can I run multiple nodes on a single computer?  *

It is possible but not advisable. One of the chief reasons to run a
cluster is to provide redundancy. To obtain the full benefits of this
redundancy, each node should reside on a separate machine. If you place
multiple nodes on a single machine and that machine fails, you lose all
of those nodes.  Given that MySQL Cluster can be run on commodity
hardware loaded with a low-cost (or even no-cost) operating system, the
expense of an extra machine or two is well worth it to safeguard
mission-critical data. It also worth noting that the requirements for a
cluster host running a management node are minimal. This task can be
accomplished with a 300 MHz Pentium or equivalent CPU and sufficient
RAM for the operating system, plus a small amount of overhead for the
*Note `ndb_mgmd': mysql-cluster-programs-ndb-mgmd.  and *Note
`ndb_mgm': mysql-cluster-programs-ndb-mgm. processes.

It is acceptable to run multiple cluster data nodes on a single host
for learning about MySQL Cluster, or for testing purposes; however,
this is not generally supported for production use.

*B.10.22: ** Can I add data nodes to a MySQL Cluster without restarting
it?  *

Not in MySQL 5.0. While a rolling restart is all that is required for
adding new management or API nodes to a MySQL Cluster (see *Note
mysql-cluster-rolling-restart::), adding data nodes is more complex,
and requires the following steps:

  1. Make a complete backup of all Cluster data.

  2. Completely shut down the cluster and all cluster node processes.

  3. Restart the cluster, using the `--initial' startup option for all
     instances of *Note `ndbd': mysql-cluster-programs-ndbd.

     *Warning*:

     Never use the `--initial' when starting *Note `ndbd':
     mysql-cluster-programs-ndbd. except when necessary to clear the
     data node file system. See *Note mysql-cluster-programs-ndbd::, for
     information about when this is required.

  4. Restore all cluster data from the backup.

*Note*:

Beginning with MySQL Cluster NDB 6.4, it is possible to add new data
nodes to a running MySQL Cluster without taking it offline. For more
information, see Adding MySQL Cluster Data Nodes Online
(http://dev.mysql.com/doc/refman/5.1/en/mysql-cluster-online-add-node.html).
However, we do not plan to add this capability in MySQL 5.0.

*B.10.23: ** Are there any limitations that I should be aware of when
using MySQL Cluster?  *

Limitations on *Note `NDB': mysql-cluster. tables in MySQL 5.0 include
the following:

   * Temporary tables are not supported; a *Note `CREATE TEMPORARY
     TABLE': create-table. statement using `ENGINE=NDB' or
     `ENGINE=NDBCLUSTER' fails with an error.

   * `FULLTEXT' indexes are not supported.

   * Index prefixes are not supported. Only complete columns may be
     indexed.

   * As of MySQL 5.0.16, MySQL Cluster supports spatial data types.
     However, spatial indexes are not supported. See *Note
     spatial-extensions::.

   * Only complete rollbacks for transactions are supported.  Partial
     rollbacks and rollbacks to savepoints are not supported. A failed
     insert due to a duplicate key or similar error causes a
     transaction to abort; when this occurs, you must issue an explicit
     *Note `ROLLBACK': commit.  and retry the transaction.

   * The maximum number of attributes allowed per table is 128, and
     attribute names cannot be any longer than 31 characters.  For each
     table, the maximum combined length of the table and database names
     is 122 characters.

   * The maximum size for a table row is 8 kilobytes, not counting
     *Note `BLOB': blob. values. There is no set limit for the number
     of rows per table. Table size limits depend on a number of
     factors, in particular on the amount of RAM available to each data
     node.

   * The *Note `NDB': mysql-cluster. engine does not support foreign
     key constraints. As with *Note `MyISAM': myisam-storage-engine.
     tables, if these are specified in a *Note `CREATE TABLE':
     create-table.  or *Note `ALTER TABLE': alter-table. statement,
     they are ignored.

For a complete listing of limitations in MySQL Cluster, see *Note
mysql-cluster-limitations::. For information about limitations in MySQL
Cluster 4.1 that are lifted in MySQL 5.0, see *Note
mysql-cluster-limitations-resolved::.

*B.10.24: ** How do I import an existing MySQL database into a MySQL
Cluster?  *

You can import databases into MySQL Cluster much as you would with any
other version of MySQL. Other than the limitations mentioned elsewhere
in this FAQ, the only other special requirement is that any tables to
be included in the cluster must use the *Note `NDB': mysql-cluster.
storage engine.  This means that the tables must be created with
`ENGINE=NDB' or `ENGINE=NDBCLUSTER'.

It is also possible to convert existing tables that use other storage
engines to *Note `NDBCLUSTER': mysql-cluster. using one or more *Note
`ALTER TABLE': alter-table.  statement. However, the definition of the
table must be compatible with the *Note `NDBCLUSTER': mysql-cluster.
storage engine prior to making the conversion. In MySQL 5.0, an
additional workaround is also required; see *Note
mysql-cluster-limitations::, for details.

*B.10.25: ** How do cluster nodes communicate with one another?  *

Cluster nodes can communicate through any of three different transport
mechanisms: TCP/IP, SHM (shared memory), and SCI (Scalable Coherent
Interface). Where available, SHM is used by default between nodes
residing on the same cluster host; however, this is considered
experimental. SCI is a high-speed (1 gigabit per second and higher),
high-availability protocol used in building scalable multi-processor
systems; it requires special hardware and drivers. See *Note
mysql-cluster-interconnects::, for more about using SCI as a transport
mechanism for MySQL Cluster.

*B.10.26: ** What is an _arbitrator_?  *

If one or more data nodes in a cluster fail, it is possible that not
all cluster data nodes will be able to `see' one another. In fact, it
is possible that two sets of data nodes might become isolated from one
another in a network partitioning, also known as a `split-brain'
scenario. This type of situation is undesirable because each set of
data nodes tries to behave as though it is the entire cluster. An
arbitrator is required to decide between the competing sets of data
nodes.

When all data nodes in at least one node group are alive, network
partitioning is not an issue, because no single subset of the cluster
can form a functional cluster on its own. The real problem arises when
no single node group has all its nodes alive, in which case network
partitioning (the `split-brain' scenario) becomes possible. Then an
arbitrator is required. All cluster nodes recognize the same node as
the arbitrator, which is normally the management server; however, it is
possible to configure any of the MySQL Servers in the cluster to act as
the arbitrator instead. The arbitrator accepts the first set of cluster
nodes to contact it, and tells the remaining set to shut down.
Arbitrator selection is controlled by the `ArbitrationRank'
configuration parameter for MySQL Server and management server nodes.
For more information about this parameter, see *Note
mysql-cluster-mgm-definition::.

The role of arbitrator does not in and of itself impose any heavy
demands upon the host so designated, and thus the arbitrator host does
not need to be particularly fast or to have extra memory especially for
this purpose.

*B.10.27: ** What data types are supported by MySQL Cluster?  *

In MySQL 5.0, MySQL Cluster supports all of the usual MySQL data types,
including (beginning with MySQL 5.0.16) those associated with MySQL's
spatial extensions; however, the *Note `NDB': mysql-cluster. storage
engine does not support spatial indexes. (Spatial indexes are supported
only by *Note `MyISAM': myisam-storage-engine.; see *Note
spatial-extensions::, for more information.) In addition, there are
some differences with regard to indexes when used with *Note `NDB':
mysql-cluster. tables.

*Note*:

In MySQL 5.0, MySQL Cluster tables (that is, tables created with
`ENGINE=NDB' or `ENGINE=NDBCLUSTER') have only fixed-width rows. This
means that (for example) each record containing a *Note `VARCHAR(255)':
char.  column will require space for 255 characters (as required for
the character set and collation being used for the table), regardless
of the actual number of characters stored therein.  This issue is fixed
in MySQL 5.1 and later; however, we do not plan to backport this
functionality to MySQL 5.0.

See *Note mysql-cluster-limitations::, for more information about these
issues.

*B.10.28: ** How do I start and stop MySQL Cluster?  *

It is necessary to start each node in the cluster separately, in the
following order:

  1. Start the management node, using the *Note `ndb_mgmd':
     mysql-cluster-programs-ndb-mgmd. command.

     You must include the `-f' or `--config-file' option to tell the
     management node where its configuration file can be found.

  2. Start each data node with the *Note `ndbd':
     mysql-cluster-programs-ndbd.  command.

     Each data node must be started with the `-c' or `--connect-string'
     option so that the data node knows how to connect to the
     management server.

  3. Start each MySQL Server (SQL node) using your preferred startup
     script, such as *Note `mysqld_safe': mysqld-safe.

     Each MySQL Server must be started with the `--ndbcluster' and
     `--ndb-connectstring' options.  These options cause mysqld to
     enable *Note `NDBCLUSTER': mysql-cluster. storage engine support
     and how to connect to the management server.

Each of these commands must be run from a system shell on the machine
housing the affected node. (You do not have to be physically present at
the machine--a remote login shell can be used for this purpose.) You
can verify that the cluster is running by starting the *Note `NDB':
mysql-cluster.  management client *Note `ndb_mgm':
mysql-cluster-programs-ndb-mgm. on the machine housing the management
node and issuing the `SHOW' or `ALL STATUS' command.

To shut down a running cluster, issue the command `SHUTDOWN' in the
management client.  Alternatively, you may enter the following command
in a system shell:

     shell> ndb_mgm -e "SHUTDOWN"

(The quotation marks in this example are optional, since there are no
spaces in the command string following the `-e' option; in addition, the
`SHUTDOWN' command, like other management client commands, is not
case-sensitive.)

Either of these commands causes the *Note `ndb_mgm':
mysql-cluster-programs-ndb-mgm, *Note `ndb_mgm':
mysql-cluster-programs-ndb-mgm, and any *Note `ndbd':
mysql-cluster-programs-ndbd.  processes to terminate gracefully. MySQL
servers running as SQL nodes can be stopped using *Note `mysqladmin
shutdown': mysqladmin.

For more information, see *Note mysql-cluster-mgm-client-commands::, and
*Note mysql-cluster-install-shutdown-restart::.

*B.10.29: ** What happens to MySQL Cluster data when the cluster is shut
down?  *

The data that was held in memory by the cluster's data nodes is written
to disk, and is reloaded into memory the next time that the cluster is
started.

*B.10.30: ** Is it a good idea to have more than one management node
for a MySQL Cluster?  *

It can be helpful as a fail-safe. Only one management node controls the
cluster at any given time, but it is possible to configure one
management node as primary, and one or more additional management nodes
to take over in the event that the primary management node fails.

See *Note mysql-cluster-config-file::, for information on how to
configure MySQL Cluster management nodes.

*B.10.31: ** Can I mix different kinds of hardware and operating
systems in one MySQL Cluster?  *

Yes, as long as all machines and operating systems have the same
`endianness' (all big-endian or all little-endian).  We are working to
overcome this limitation in a future MySQL Cluster release.

It is also possible to use software from different MySQL Cluster
releases on different nodes. However, we support this only as part of a
rolling upgrade procedure (see *Note mysql-cluster-rolling-restart::).

*B.10.32: ** Can I run two data nodes on a single host? Two SQL nodes?
*

Yes, it is possible to do this. In the case of multiple data nodes, it
is advisable (but not required) for each node to use a different data
directory. If you want to run multiple SQL nodes on one machine, each
instance of *Note `mysqld': mysqld. must use a different TCP/IP port.
However, in MySQL 5.0, running more than one cluster node of a given
type per machine is generally not encouraged or supported for
production use.

We also advise against running data nodes and SQL nodes together on the
same host, since the *Note `ndbd': mysql-cluster-programs-ndbd. and
*Note `mysqld': mysqld. processes may compete for memory.

*B.10.33: ** Can I use host names with MySQL Cluster?  *

Yes, it is possible to use DNS and DHCP for cluster hosts.  However, if
your application requires `five nines' availability, you should use
fixed (numeric) IP addresses, since making communication between
Cluster hosts dependent on services such as DNS and DHCP introduces
additional potential points of failure.

*B.10.34: ** How do I handle MySQL users in a MySQL Cluster having
multiple MySQL servers?  *

MySQL user accounts and privileges are _not_ automatically propagated
between different MySQL servers accessing the same MySQL Cluster.
Therefore, you must make sure that these are copied between the SQL
nodes yourself. You can do this manually, or automate the task with
scripts.

*Warning*:

Do not attempt to work around this issue by converting the MySQL system
tables to use the *Note `NDBCLUSTER': mysql-cluster. storage engine.
Only the *Note `MyISAM': myisam-storage-engine. storage engine is
supported for these tables.

*B.10.35: ** How do I continue to send queries in the event that one of
the SQL nodes fails?  *

MySQL Cluster does not provide any sort of automatic failover between
SQL nodes. Your application must be prepared to handlethe loss of SQL
nodes and to fail over between them.

*B.10.36: ** How do I back up and restore a MySQL Cluster?  *

You can use the NDB native backup and restore functionality in the
MySQL Cluster management client and the *Note `ndb_restore':
mysql-cluster-programs-ndb-restore. program. See *Note
mysql-cluster-backup::, and *Note mysql-cluster-programs-ndb-restore::.

You can also use the traditional functionality provided for this
purpose in *Note `mysqldump': mysqldump. and the MySQL server.  See
*Note mysqldump::, for more information.

*B.10.37: ** What is an `angel process'?  *

This process monitors and, if necessary, attempts to restart the data
node process. If you check the list of active processes on your system
after starting *Note `ndbd': mysql-cluster-programs-ndbd, you can see
that there are actually 2 processes running by that name, as shown here
(we omit the output from *Note `ndb_mgmd':
mysql-cluster-programs-ndb-mgmd.  and *Note `ndbd':
mysql-cluster-programs-ndbd. for brevity):

     shell> ./ndb_mgmd

     shell> ps aux | grep ndb
     me      23002  0.0  0.0 122948  3104 ?        Ssl  14:14   0:00 ./ndb_mgmd
     me      23025  0.0  0.0   5284   820 pts/2    S+   14:14   0:00 grep ndb

     shell> ./ndbd -c 127.0.0.1 --initial

     shell> ps aux | grep ndb
     me      23002  0.0  0.0 123080  3356 ?        Ssl  14:14   0:00 ./ndb_mgmd
     me      23096  0.0  0.0  35876  2036 ?        Ss   14:14   0:00 ./ndbd -c 127.0.0.1 --initial
     me      23097  1.0  2.4 524116 91096 ?        Sl   14:14   0:00 ./ndbd -c 127.0.0.1 --initial
     me      23168  0.0  0.0   5284   812 pts/2    R+   14:15   0:00 grep ndb

The *Note `ndbd': mysql-cluster-programs-ndbd. process showing 0 memory
and CPU usage is the angel process. It actually does use a very small
amount of each, of course. It simply checks to see if the main *Note
`ndbd': mysql-cluster-programs-ndbd. process (the primary data node
process that actually handles the data) is running. If permitted to do
so (for example, if the `StopOnError' configuration parameter is set to
false--see *Note mysql-cluster-params-ndbd::), the angel process tries
to restart the primary data node process.


File: manual.info,  Node: faqs-cjk,  Next: faqs-connectors-apis,  Prev: faqs-mysql-cluster,  Up: faqs

B.11 MySQL 5.0 FAQ: MySQL Chinese, Japanese, and Korean Character Sets
======================================================================

This set of Frequently Asked Questions derives from the experience of
MySQL's Support and Development groups in handling many inquiries about
CJK (Chinese-Japanese-Korean) issues.

*Questions*
   * B.11.1: What CJK character sets are available in MySQL?

   * B.11.2: I have inserted CJK characters into my table. Why does
     *Note `SELECT': select. display them as `?' characters?

   * B.11.3: What problems should I be aware of when working with the
     Big5 Chinese character set?

   * B.11.4: Why do Japanese character set conversions fail?

   * B.11.5: What should I do if I want to convert SJIS `81CA' to
     `cp932'?

   * B.11.6: How does MySQL represent the Yen (`¥') sign?

   * B.11.7: Does MySQL plan to make a separate character set where
     `5C' is the Yen sign, as at least one other major DBMS does?

   * B.11.8: Of what issues should I be aware when working with Korean
     character sets in MySQL?

   * B.11.9: Why do I get `Incorrect string value' error messages?

   * B.11.10: Why does my GUI front end or browser not display CJK
     characters correctly in my application using Access, PHP, or
     another API?

   * B.11.11: I've upgraded to MySQL 5.0. How can I revert to behavior
     like that in MySQL 4.0 with regard to character sets?

   * B.11.12: Why do some `LIKE' and `FULLTEXT' searches with CJK
     characters fail?

   * B.11.13: How do I know whether character X is available in all
     character sets?

   * B.11.14: Why do CJK strings sort incorrectly in Unicode? (I)

   * B.11.15: Why do CJK strings sort incorrectly in Unicode? (II)

   * B.11.16: Why are my supplementary characters rejected by MySQL?

   * B.11.17: Shouldn't it be `CJKV'?

   * B.11.18: Does MySQL allow CJK characters to be used in database
     and table names?

   * B.11.19: Where can I find translations of the MySQL Manual into
     Chinese, Japanese, and Korean?

   * B.11.20: Where can I get help with CJK and related issues in MySQL?

*Questions and Answers* *B.11.1: ** What CJK character sets are
available in MySQL?  *

The list of CJK character sets may vary depending on your MySQL
version. For example, the `eucjpms' character set was not supported
prior to MySQL 5.0.3 (see *Note news-5-0-3::). However, since the name
of the applicable language appears in the `DESCRIPTION' column for
every entry in the *Note `INFORMATION_SCHEMA.CHARACTER_SETS':
character-sets-table.  table, you can obtain a current list of all the
non-Unicode CJK character sets using this query:

     mysql> SELECT CHARACTER_SET_NAME, DESCRIPTION
         -> FROM INFORMATION_SCHEMA.CHARACTER_SETS
         -> WHERE DESCRIPTION LIKE '%Chinese%'
         -> OR DESCRIPTION LIKE '%Japanese%'
         -> OR DESCRIPTION LIKE '%Korean%'
         -> ORDER BY CHARACTER_SET_NAME;
     +--------------------+---------------------------+
     | CHARACTER_SET_NAME | DESCRIPTION               |
     +--------------------+---------------------------+
     | big5               | Big5 Traditional Chinese  |
     | cp932              | SJIS for Windows Japanese |
     | eucjpms            | UJIS for Windows Japanese |
     | euckr              | EUC-KR Korean             |
     | gb2312             | GB2312 Simplified Chinese |
     | gbk                | GBK Simplified Chinese    |
     | sjis               | Shift-JIS Japanese        |
     | ujis               | EUC-JP Japanese           |
     +--------------------+---------------------------+
     8 rows in set (0.01 sec)

(See *Note character-sets-table::, for more information.)

MySQL supports the two common variants of the _GB_ (_Guojia Biaozhun_,
or _National Standard_, or _Simplified Chinese_) character sets which
are official in the People's Republic of China: `gb2312' and `gbk'.
Sometimes people try to insert `gbk' characters into `gb2312', and it
works most of the time because `gbk' is a superset of `gb2312'--but
eventually they try to insert a rarer Chinese character and it doesn't
work. (See Bug #16072 for an example).

Here, we try to clarify exactly what characters are legitimate in
`gb2312' or `gbk', with reference to the official documents. Please
check these references before reporting `gb2312' or `gbk' bugs.

   * For a complete listing of the `gb2312' characters, ordered
     according to the `gb2312_chinese_ci' collation: gb2312
     (http://www.collation-charts.org/mysql60/by-charset.html#gb2312)

   * MySQL's `gbk' is in reality `Microsoft code page 936'. This
     differs from the official `gbk' for characters `A1A4' (middle dot),
     `A1AA' (em dash), `A6E0-A6F5', and `A8BB-A8C0'.

   * For a listing of `gbk'/Unicode mappings, see
     `http://www.unicode.org/Public/MAPPINGS/VENDORS/MICSFT/WINDOWS/CP936.TXT'.

   * For MySQL's listing of `gbk' characters, see gbk
     (http://www.collation-charts.org/mysql60/by-charset.html#gbk).

*B.11.2: ** I have inserted CJK characters into my table. Why does
*Note `SELECT': select. display them as `?' characters?  *

This problem is usually due to a setting in MySQL that doesn't match
the settings for the application program or the operating system. Here
are some common steps for correcting these types of issues:

   * _Be certain of what MySQL version you are using_.

     Use the statement `SELECT VERSION();' to determine this.

   * _Make sure that the database is actually using the desired
     character set_.

     People often think that the client character set is always the
     same as either the server character set or the character set used
     for display purposes. However, both of these are false
     assumptions. You can make sure by checking the result of `SHOW
     CREATE TABLE TABLENAME' or--better yet--by using this statement:

          SELECT character_set_name, collation_name
              FROM information_schema.columns
              WHERE table_schema = your_database_name
                  AND table_name = your_table_name
                  AND column_name = your_column_name;

   * _Determine the hexadecimal value of the character or characters
     that are not being displayed correctly_.

     You can obtain this information for a column COLUMN_NAME in the
     table TABLE_NAME using the following query:

          SELECT HEX(COLUMN_NAME)
          FROM TABLE_NAME;

     `3F' is the encoding for the `?' character; this means that `?' is
     the character actually stored in the column. This most often
     happens because of a problem converting a particular character
     from your client character set to the target character set.

   * _Make sure that a round trip possible--that is, when you select
     LITERAL (or _INTRODUCER HEXADECIMAL-VALUE), you obtain LITERAL as a
     result_.

     For example, the Japanese _Katakana_ character _Pe_ (`ペ'')
     exists in all CJK character sets, and has the code point value
     (hexadecimal coding) `0x30da'. To test a round trip for this
     character, use this query:

          SELECT 'ペ' AS `ペ`;         /* or SELECT _ucs2 0x30da; */

     If the result is not also `ペ', then the round trip has failed.

     For bug reports regarding such failures, we might ask you to
     follow up with `SELECT HEX('ペ');'. Then we can determine whether
     the client encoding is correct.

   * _Make sure that the problem is not with the browser or other
     application, rather than with MySQL_.

     Use the *Note `mysql': mysql. client program (on Windows: *Note
     `mysql.exe': mysql.) to accomplish this task. If *Note `mysql':
     mysql. displays correctly but your application doesn't, then your
     problem is probably due to system settings.

     To find out what your settings are, use the *Note `SHOW
     VARIABLES': show-variables. statement, whose output should
     resemble what is shown here:

          mysql> SHOW VARIABLES LIKE 'char%';
          +--------------------------+----------------------------------------+
          | Variable_name            | Value                                  |
          +--------------------------+----------------------------------------+
          | character_set_client     | utf8                                   |
          | character_set_connection | utf8                                   |
          | character_set_database   | latin1                                 |
          | character_set_filesystem | binary                                 |
          | character_set_results    | utf8                                   |
          | character_set_server     | latin1                                 |
          | character_set_system     | utf8                                   |
          | character_sets_dir       | /usr/local/mysql/share/mysql/charsets/ |
          +--------------------------+----------------------------------------+
          8 rows in set (0.03 sec)

     These are typical character-set settings for an
     international-oriented client (notice the use of `utf8' Unicode)
     connected to a server in the West (`latin1' is a West Europe
     character set and a default for MySQL).

     Although Unicode (usually the `utf8' variant on Unix, and the
     `ucs2' variant on Windows) is preferable to Latin, it is often not
     what your operating system utilities support best. Many Windows
     users find that a Microsoft character set, such as `cp932' for
     Japanese Windows, is suitable.

     If you cannot control the server settings, and you have no idea
     what your underlying computer is, then try changing to a common
     character set for the country that you're in (`euckr' = Korea;
     `gb2312' or `gbk' = People's Republic of China; `big5' = Taiwan;
     `sjis', `ujis', `cp932', or `eucjpms' = Japan; `ucs2' or `utf8' =
     anywhere). Usually it is necessary to change only the client and
     connection and results settings. There is a simple statement which
     changes all three at once: `SET NAMES'. For example:

          SET NAMES 'big5';

     Once the setting is correct, you can make it permanent by editing
     `my.cnf' or `my.ini'. For example you might add lines looking like
     these:

          [mysqld]
          character-set-server=big5
          [client]
          default-character-set=big5

     It is also possible that there are issues with the API
     configuration setting being used in your application; see `Why
     does my GUI front end or browser not display CJK characters
     correctly...?' for more information.

*B.11.3: ** What problems should I be aware of when working with the
Big5 Chinese character set?  *

MySQL supports the Big5 character set which is common in Hong Kong and
Taiwan (Republic of China). MySQL's `big5' is in reality Microsoft code
page 950, which is very similar to the original `big5' character set.
We changed to this

character set starting with MySQL version 4.1.16 / 5.0.16 (as a result
of Bug #12476). For example, the following statements work in current
versions of MySQL, but not in old versions:

     mysql> CREATE TABLE big5 (BIG5 CHAR(1) CHARACTER SET BIG5);
     Query OK, 0 rows affected (0.13 sec)

     mysql> INSERT INTO big5 VALUES (0xf9dc);
     Query OK, 1 row affected (0.00 sec)

     mysql> SELECT * FROM big5;
     +------+
     | big5 |
     +------+
     | 嫺  |
     +------+
     1 row in set (0.02 sec)

A feature request for adding `HKSCS' extensions has been filed. People
who need this extension may find the suggested patch for Bug #13577 to
be of interest.

*B.11.4: ** Why do Japanese character set conversions fail?  *

MySQL supports the `sjis', `ujis', `cp932', and `eucjpms' character
sets, as well as Unicode. A common need is to convert between character
sets. For example, there might be a Unix server (typically with `sjis'
or `ujis') and a Windows client (typically with `cp932').

In the following conversion table, the `ucs2' column represents the
source, and the `sjis', `cp932', `ujis', and `eucjpms' columns
represent the destinations--that is, the last 4 columns provide the
hexadecimal result when we use `CONVERT(ucs2)' or we assign a `ucs2'
column containing the value to an `sjis', `cp932', `ujis', or `eucjpms'
column.

Character Name                ucs2      sjis      cp932     ujis      eucjpms
BROKEN BAR                    00A6      3F        3F        8FA2C3    3F
FULLWIDTH BROKEN BAR          FFE4      3F        FA55      3F        8FA2
YEN SIGN                      00A5      3F        3F        20        3F
FULLWIDTH YEN SIGN            FFE5      818F      818F      A1EF      3F
TILDE                         007E      7E        7E        7E        7E
OVERLINE                      203E      3F        3F        20        3F
HORIZONTAL BAR                2015      815C      815C      A1BD      A1BD
EM DASH                       2014      3F        3F        3F        3F
REVERSE SOLIDUS               005C      815F      5C        5C        5C
FULLWIDTH ""                  FF3C      3F        815F      3F        A1C0
WAVE DASH                     301C      8160      3F        A1C1      3F
FULLWIDTH TILDE               FF5E      3F        8160      3F        A1C1
DOUBLE VERTICAL LINE          2016      8161      3F        A1C2      3F
PARALLEL TO                   2225      3F        8161      3F        A1C2
MINUS SIGN                    2212      817C      3F        A1DD      3F
FULLWIDTH HYPHEN-MINUS        FF0D      3F        817C      3F        A1DD
CENT SIGN                     00A2      8191      3F        A1F1      3F
FULLWIDTH CENT SIGN           FFE0      3F        8191      3F        A1F1
POUND SIGN                    00A3      8192      3F        A1F2      3F
FULLWIDTH POUND SIGN          FFE1      3F        8192      3F        A1F2
NOT SIGN                      00AC      81CA      3F        A2CC      3F
FULLWIDTH NOT SIGN            FFE2      3F        81CA      3F        A2CC

Now consider the following portion of the table.

                                         ucs2        sjis        cp932
NOT SIGN                                 00AC        81CA        3F
FULLWIDTH NOT SIGN                       FFE2        3F          81CA

This means that MySQL converts the `NOT SIGN' (Unicode `U+00AC') to
`sjis' code point `0x81CA' and to `cp932' code point `3F'.  (`3F' is
the question mark (`?')--this is what is always used when the
conversion cannot be performed.

*B.11.5: ** What should I do if I want to convert SJIS `81CA' to
`cp932'?  *

Our answer is: `?'. There are serious complaints about this: many
people would prefer a `loose' conversion, so that `81CA (NOT SIGN)' in
`sjis' becomes `81CA (FULLWIDTH NOT SIGN)' in `cp932'. We are
considering a change to this behavior.

*B.11.6: ** How does MySQL represent the Yen (`¥') sign?  *

A problem arises because some versions of Japanese character sets (both
`sjis' and `euc') treat `5C' as a _reverse solidus_ (`\'--also known as
a backslash), and others treat it as a yen sign (`¥').

MySQL follows only one version of the JIS (Japanese Industrial
Standards) standard description. In MySQL, _`5C' is always the reverse
solidus (`\')_.

*B.11.7: ** Does MySQL plan to make a separate character set where `5C'
is the Yen sign, as at least one other major DBMS does?  *

This is one possible solution to the Yen sign issue; however, this will
not happen in MySQL 5.1 or 6.0.

*B.11.8: ** Of what issues should I be aware when working with Korean
character sets in MySQL?  *

In theory, while there have been several versions of the `euckr'
(_Extended Unix Code Korea_) character set, only one problem has been
noted.

We use the `ASCII' variant of EUC-KR, in which the code point `0x5c' is
REVERSE SOLIDUS, that is `\', instead of the `KS-Roman' variant of
EUC-KR, in which the code point `0x5c' is `WON SIGN'(`₩'). This means
that you cannot convert Unicode `U+20A9' to `euckr':

     mysql> SELECT
         ->     CONVERT('₩' USING euckr) AS euckr,
         ->     HEX(CONVERT('₩' USING euckr)) AS hexeuckr;
     +-------+----------+
     | euckr | hexeuckr |
     +-------+----------+
     | ?     | 3F       |
     +-------+----------+
     1 row in set (0.00 sec)

MySQL's graphic Korean chart is here: euckr
(http://www.collation-charts.org/mysql60/by-charset.html#euckr).

*B.11.9: ** Why do I get `Incorrect string value' error messages?  *

For illustration, we'll create a table with one Unicode (`ucs2') column
and one Chinese (`gb2312') column.

     mysql> CREATE TABLE ch
         -> (ucs2 CHAR(3) CHARACTER SET ucs2,
         -> gb2312 CHAR(3) CHARACTER SET gb2312);
     Query OK, 0 rows affected (0.05 sec)

We'll try to place the rare character `汌' in both columns.

     mysql> INSERT INTO ch VALUES ('A汌B','A汌B');
     Query OK, 1 row affected, 1 warning (0.00 sec)

Ah, there is a warning. Use the following statement to see what it is:

     mysql> SHOW WARNINGS\G
     *************************** 1. row ***************************
       Level: Warning
        Code: 1366
     Message: Incorrect string value: '\xE6\xB1\x8CB' for column 'gb2312' at row 1
     1 row in set (0.00 sec)

So it is a warning about the `gb2312' column only.

     mysql> SELECT ucs2,HEX(ucs2),gb2312,HEX(gb2312) FROM ch;
     +-------+--------------+--------+-------------+
     | ucs2  | HEX(ucs2)    | gb2312 | HEX(gb2312) |
     +-------+--------------+--------+-------------+
     | A汌B | 00416C4C0042 | A?B    | 413F42      |
     +-------+--------------+--------+-------------+
     1 row in set (0.00 sec)

Several things need explanation here:

  1. The fact that it is a `warning' rather than an `error' is
     characteristic of MySQL. We like to try to do what we can, to get
     the best fit, rather than give up.

  2. The `汌' character is not in the `gb2312' character set. We
     described that problem earlier.

  3. If you are using an old version of MySQL, you will probably see a
     different message.

  4. With `sql_mode=TRADITIONAL', there would be an error message,
     rather than a warning.

*B.11.10: ** Why does my GUI front end or browser not display CJK
characters correctly in my application using Access, PHP, or another
API?  *

Obtain a direct connection to the server using the *Note `mysql':
mysql. client (Windows: *Note `mysql.exe': mysql.), and try the same
query there. If *Note `mysql': mysql. responds correctly, then the
trouble may be that your application interface requires initialization.
Use *Note `mysql': mysql. to tell you what character set or sets it
uses with the statement `SHOW VARIABLES LIKE 'char%';'. If you are
using Access, then you are most likely connecting with Connector/ODBC.
In this case, you should check *Note connector-odbc-configuration::.
If, for instance, you use `big5', you would enter `SET NAMES 'big5''.
(Note that no `;' is required in this case). If you are using ASP, you
might need to add `SET NAMES' in the code. Here is an example that has
worked in the past:

     <%
     Session.CodePage=0
     Dim strConnection
     Dim Conn
     strConnection="driver={MySQL ODBC 3.51 Driver};server=SERVER;uid=USERNAME;" \
                    & "pwd=PASSWORD;database=DATABASE;stmt=SET NAMES 'big5';"
     Set Conn = Server.CreateObject("ADODB.Connection")
     Conn.Open strConnection
     %>

In much the same way, if you are using any character set other than
`latin1' with Connector/Net, then you must specify the character set in
the connection string. See *Note
connector-net-programming-connecting::, for more information.

If you are using PHP, try this:

     <?php
       $link = mysql_connect($host, $usr, $pwd);

       mysql_select_db($db);

       if( mysql_error() ) { print "Database ERROR: " . mysql_error(); }
       mysql_query("SET NAMES 'utf8'", $link);
     ?>

In this case, we used `SET NAMES' to change `character_set_client' and
`character_set_connection' and `character_set_results'.

We encourage the use of the newer `mysqli' extension, rather than
`mysql'. Using `mysqli', the previous example could be rewritten as
shown here:

     <?php
       $link = new mysqli($host, $usr, $pwd, $db);

       if( mysqli_connect_errno() )
       {
         printf("Connect failed: %s\n", mysqli_connect_error());
         exit();
       }

       $link->query("SET NAMES 'utf8'");
     ?>

Another issue often encountered in PHP applications has to do with
assumptions made by the browser. Sometimes adding or changing a
`<meta>' tag suffices to correct the problem: for example, to insure
that the user agent interprets page content as `UTF-8', you should
include `<meta http-equiv="Content-Type" content="text/html;
charset=utf-8">' in the `<head>' of the HTML page.

If you are using Connector/J, see *Note
connector-j-reference-charsets::.

*B.11.11: ** I've upgraded to MySQL 5.0. How can I revert to behavior
like that in MySQL 4.0 with regard to character sets?  *

In MySQL Version 4.0, there was a single `global' character set for
both server and client, and the decision as to which character to use
was made by the server administrator.  This changed starting with MySQL
Version 4.1. What happens now is a `handshake', as described in *Note
charset-connection:::

When a client connects, it sends to the server the name of the
character set that it wants to use. The server uses the name to set the
`character_set_client', `character_set_results', and
`character_set_connection' system variables. In effect, the server
performs a `SET NAMES' operation using the character set name.

The effect of this is that you cannot control the client character set
by starting *Note `mysqld': mysqld. with `--character-set-server=utf8'.
However, some of our Asian customers have said that they prefer the
MySQL 4.0 behavior. To make it possible to retain this behavior, we
added a *Note `mysqld': mysqld. switch,
`--character-set-client-handshake', which can be turned off with
`--skip-character-set-client-handshake'.  If you start *Note `mysqld':
mysqld. with `--skip-character-set-client-handshake', then, when a
client connects, it sends to the server the name of the character set
that it wants to use--however, _the server ignores this request from the
client_.

By way of example, suppose that your favorite server character set is
`latin1' (unlikely in a CJK area, but this is the default value).
Suppose further that the client uses `utf8' because this is what the
client's operating system supports. Now, start the server with `latin1'
as its default character set:

     mysqld --character-set-server=latin1

And then start the client with the default character set `utf8':

     mysql --default-character-set=utf8

The current settings can be seen by viewing the output of *Note `SHOW
VARIABLES': show-variables.:

     mysql> SHOW VARIABLES LIKE 'char%';
     +--------------------------+----------------------------------------+
     | Variable_name            | Value                                  |
     +--------------------------+----------------------------------------+
     | character_set_client     | utf8                                   |
     | character_set_connection | utf8                                   |
     | character_set_database   | latin1                                 |
     | character_set_filesystem | binary                                 |
     | character_set_results    | utf8                                   |
     | character_set_server     | latin1                                 |
     | character_set_system     | utf8                                   |
     | character_sets_dir       | /usr/local/mysql/share/mysql/charsets/ |
     +--------------------------+----------------------------------------+
     8 rows in set (0.01 sec)

Now stop the client, and then stop the server using *Note `mysqladmin':
mysqladmin. Then start the server again, but this time tell it to skip
the handshake like so:

     mysqld --character-set-server=utf8 --skip-character-set-client-handshake

Start the client with `utf8' once again as the default character set,
then display the current settings:

     mysql> SHOW VARIABLES LIKE 'char%';
     +--------------------------+----------------------------------------+
     | Variable_name            | Value                                  |
     +--------------------------+----------------------------------------+
     | character_set_client     | latin1                                 |
     | character_set_connection | latin1                                 |
     | character_set_database   | latin1                                 |
     | character_set_filesystem | binary                                 |
     | character_set_results    | latin1                                 |
     | character_set_server     | latin1                                 |
     | character_set_system     | utf8                                   |
     | character_sets_dir       | /usr/local/mysql/share/mysql/charsets/ |
     +--------------------------+----------------------------------------+
     8 rows in set (0.01 sec)

As you can see by comparing the differing results from *Note `SHOW
VARIABLES': show-variables, the server ignores the client's initial
settings if the `--skip-character-set-client-handshake' is used.

*B.11.12: ** Why do some `LIKE' and `FULLTEXT' searches with CJK
characters fail?  *

There is a very simple problem with `LIKE' searches on *Note `BINARY':
binary-varbinary. and *Note `BLOB': blob. columns: we need to know the
end of a character. With multi-byte character sets, different
characters might have different octet lengths. For example, in `utf8',
`A' requires one byte but `ペ' requires three bytes, as shown here:

     +-------------------------+---------------------------+
     | OCTET_LENGTH(_utf8 'A') | OCTET_LENGTH(_utf8 'ペ') |
     +-------------------------+---------------------------+
     |                       1 |                         3 |
     +-------------------------+---------------------------+
     1 row in set (0.00 sec)

If we don't know where the first character ends, then we don't know
where the second character begins, in which case even very simple
searches such as `LIKE '_A%'' fail. The solution is to use a regular CJK
character set in the first place, or to convert to a CJK character set
before comparing.

This is one reason why MySQL cannot allow encodings of nonexistent
characters. If it is not strict about rejecting bad input, then it has
no way of knowing where characters end.

For `FULLTEXT' searches, we need to know where words begin and end.
With Western languages, this is rarely a problem because most (if not
all) of these use an easy-to-identify word boundary--the space
character.  However, this is not usually the case with Asian writing. We
could use arbitrary halfway measures, like assuming that all Han
characters represent words, or (for Japanese) depending on changes from
Katakana to Hiragana due to grammatical endings.  However, the only
sure solution requires a comprehensive word list, which means that we
would have to include a dictionary in the server for each Asian
language supported. This is simply not feasible.

*B.11.13: ** How do I know whether character X is available in all
character sets?  *

The majority of simplified Chinese and basic nonhalfwidth Japanese
_Kana_ characters appear in all CJK character sets. This stored
procedure accepts a `UCS-2' Unicode character, converts it to all other
character sets, and displays the results in hexadecimal.

     DELIMITER //

     CREATE PROCEDURE p_convert(ucs2_char CHAR(1) CHARACTER SET ucs2)
     BEGIN

     CREATE TABLE tj
                  (ucs2 CHAR(1) character set ucs2,
                   utf8 CHAR(1) character set utf8,
                   big5 CHAR(1) character set big5,
                   cp932 CHAR(1) character set cp932,
                   eucjpms CHAR(1) character set eucjpms,
                   euckr CHAR(1) character set euckr,
                   gb2312 CHAR(1) character set gb2312,
                   gbk CHAR(1) character set gbk,
                   sjis CHAR(1) character set sjis,
                   ujis CHAR(1) character set ujis);

     INSERT INTO tj (ucs2) VALUES (ucs2_char);

     UPDATE tj SET utf8=ucs2,
                   big5=ucs2,
                   cp932=ucs2,
                   eucjpms=ucs2,
                   euckr=ucs2,
                   gb2312=ucs2,
                   gbk=ucs2,
                   sjis=ucs2,
                   ujis=ucs2;

     /* If there is a conversion problem, UPDATE will produce a warning. */

     SELECT hex(ucs2) AS ucs2,
            hex(utf8) AS utf8,
            hex(big5) AS big5,
            hex(cp932) AS cp932,
            hex(eucjpms) AS eucjpms,
            hex(euckr) AS euckr,
            hex(gb2312) AS gb2312,
            hex(gbk) AS gbk,
            hex(sjis) AS sjis,
            hex(ujis) AS ujis
     FROM tj;

     DROP TABLE tj;

     END//

The input can be any single `ucs2' character, or it can be the code
point value (hexadecimal representation) of that character. For
example, from Unicode's list of `ucs2' encodings and names
(`http://www.unicode.org/Public/UNIDATA/UnicodeData.txt'), we know that
the _Katakana_ character _Pe_ appears in all CJK character sets, and
that its code point value is `0x30da'. If we use this value as the
argument to `p_convert()', the result is as shown here:

     mysql> CALL p_convert(0x30da)//
     +------+--------+------+-------+---------+-------+--------+------+------+------+
     | ucs2 | utf8   | big5 | cp932 | eucjpms | euckr | gb2312 | gbk  | sjis | ujis |
     +------+--------+------+-------+---------+-------+--------+------+------+------+
     | 30DA | E3839A | C772 | 8379  | A5DA    | ABDA  | A5DA   | A5DA | 8379 | A5DA |
     +------+--------+------+-------+---------+-------+--------+------+------+------+
     1 row in set (0.04 sec)

Since none of the column values is `3F'--that is, the question mark
character (`?')--we know that every conversion worked.

*B.11.14: ** Why do CJK strings sort incorrectly in Unicode? (I) *

Sometimes people observe that the result of a `utf8_unicode_ci' or
`ucs2_unicode_ci' search, or of an `ORDER BY' sort is not what they
think a native would expect. Although we never rule out the possibility
that there is a bug, we have found in the past that many people do not
read correctly the standard table of weights for the Unicode Collation
Algorithm. MySQL uses the table found at
`http://www.unicode.org/Public/UCA/4.0.0/allkeys-4.0.0.txt'.  This is
not the first table you will find by navigating from the `unicode.org'
home page, because MySQL uses the older 4.0.0 `allkeys' table, rather
than the more recent 4.1.0 table. (The newer `'520'' collations in
MySQL 5.6 use the 5.2 `allkeys' table.) This is because we are very
wary about changing ordering which affects indexes, lest we bring about
situations such as that reported in Bug #16526, illustrated as follows:

     mysql< CREATE TABLE tj (s1 CHAR(1) CHARACTER SET utf8 COLLATE utf8_unicode_ci);
     Query OK, 0 rows affected (0.05 sec)

     mysql> INSERT INTO tj VALUES ('が'),('か');
     Query OK, 2 rows affected (0.00 sec)
     Records: 2  Duplicates: 0  Warnings: 0

     mysql> SELECT * FROM tj WHERE s1 = 'か';
     +------+
     | s1   |
     +------+
     | が  |
     | か  |
     +------+
     2 rows in set (0.00 sec)

The character in the first result row is not the one that we searched
for. Why did MySQL retrieve it? First we look for the Unicode code
point value, which is possible by reading the hexadecimal number for
the `ucs2' version of the characters:

     mysql> SELECT s1, HEX(CONVERT(s1 USING ucs2)) FROM tj;
     +------+-----------------------------+
     | s1   | HEX(CONVERT(s1 USING ucs2)) |
     +------+-----------------------------+
     | が  | 304C                        |
     | か  | 304B                        |
     +------+-----------------------------+
     2 rows in set (0.03 sec)

Now we search for `304B' and `304C' in the `4.0.0 allkeys' table, and
find these lines:

     304B  ; [.1E57.0020.000E.304B] # HIRAGANA LETTER KA
     304C  ; [.1E57.0020.000E.304B][.0000.0140.0002.3099] # HIRAGANA LETTER GA; QQCM

The official Unicode names (following the `#' mark) tell us the
Japanese syllabary (Hiragana), the informal classification (letter,
digit, or punctuation mark), and the Western identifier (`KA' or `GA',
which happen to be voiced and unvoiced components of the same letter
pair). More importantly, the _primary weight_ (the first hexadecimal
number inside the square brackets) is `1E57' on both lines. For
comparisons in both searching and sorting, MySQL pays attention to the
primary weight only, ignoring all the other numbers. This means that we
are sorting `が' and `か' correctly according to the Unicode
specification. If we wanted to distinguish them, we'd have to use a
non-UCA (Unicode Collation Algorithm) collation (`utf8_bin' or
`utf8_general_ci'), or to compare the `HEX()' values, or use `ORDER BY
CONVERT(s1 USING sjis)'. Being correct `according to Unicode' isn't
enough, of course: the person who submitted the bug was equally
correct. We plan to add another collation for Japanese according to the
JIS X 4061 standard, in which voiced/unvoiced letter pairs like
`KA'/`GA' are distinguishable for ordering purposes.

*B.11.15: ** Why do CJK strings sort incorrectly in Unicode? (II) *

If you are using Unicode (`ucs2' or `utf8'), and you know what the
Unicode sort order is (see *Note faqs-cjk::), but MySQL still seems to
sort your table incorrectly, then you should first verify the table
character set:

     mysql> SHOW CREATE TABLE t\G
     ******************** 1. row ******************
     Table: t
     Create Table: CREATE TABLE `t` (
     `s1` char(1) CHARACTER SET ucs2 DEFAULT NULL
     ) ENGINE=MyISAM DEFAULT CHARSET=latin1
     1 row in set (0.00 sec)

Since the character set appears to be correct, let's see what
information the *Note `INFORMATION_SCHEMA.COLUMNS': columns-table. table
can provide about this column:

     mysql> SELECT COLUMN_NAME, CHARACTER_SET_NAME, COLLATION_NAME
         -> FROM INFORMATION_SCHEMA.COLUMNS
         -> WHERE COLUMN_NAME = 's1'
         -> AND TABLE_NAME = 't';
     +-------------+--------------------+-----------------+
     | COLUMN_NAME | CHARACTER_SET_NAME | COLLATION_NAME  |
     +-------------+--------------------+-----------------+
     | s1          | ucs2               | ucs2_general_ci |
     +-------------+--------------------+-----------------+
     1 row in set (0.01 sec)

(See *Note columns-table::, for more information.)

You can see that the collation is `ucs2_general_ci' instead of
`ucs2_unicode_ci'. The reason why this is so can be found using `SHOW
CHARSET', as shown here:

     mysql> SHOW CHARSET LIKE 'ucs2%';
     +---------+---------------+-------------------+--------+
     | Charset | Description   | Default collation | Maxlen |
     +---------+---------------+-------------------+--------+
     | ucs2    | UCS-2 Unicode | ucs2_general_ci   |      2 |
     +---------+---------------+-------------------+--------+
     1 row in set (0.00 sec)

For `ucs2' and `utf8', the default collation is `general'. To specify a
Unicode collation, use `COLLATE ucs2_unicode_ci'.

*B.11.16: ** Why are my supplementary characters rejected by MySQL?  *

Before MySQL 5.5.3, MySQL does not support supplementary
characters--that is, characters which need more than 3 bytes--for
`UTF-8'. We support only what Unicode calls the _Basic Multilingual
Plane / Plane 0_. Only a few very rare Han characters are
supplementary; support for them is uncommon. This has led to reports
such as that found in Bug #12600, which we rejected as `not a bug'.
With `utf8', we must truncate an input string when we encounter bytes
that we don't understand. Otherwise, we wouldn't know how long the bad
multi-byte character is.

One possible workaround is to use `ucs2' instead of `utf8', in which
case the `bad' characters are changed to question marks; however, no
truncation takes place. You can also change the data type to *Note
`BLOB': blob. or *Note `BINARY': binary-varbinary, which perform no
validity checking.

As of MySQL 5.5.3, Unicode support is extended to include supplementary
characters by means of additional Unicode character sets: `utf16',
`utf32', and 4-byte `utf8mb4'.  These character sets support
supplementary Unicode characters outside the Basic Multilingual Plane
(BMP).

*B.11.17: ** Shouldn't it be `CJKV'?  *

No. The term `CJKV' (_Chinese Japanese Korean Vietnamese_) refers to
Vietnamese character sets which contain Han (originally Chinese)
characters. MySQL has no plan to support the old Vietnamese script
using Han characters. MySQL does of course support the modern Vietnamese
script with Western characters.

As of MySQL 5.6, there are Vietnamese collations for Unicode character
sets, as described in *Note charset-unicode-sets::.

*B.11.18: ** Does MySQL allow CJK characters to be used in database and
table names?  *

This issue is fixed in MySQL 5.1, by automatically rewriting the names
of the corresponding directories and files.

For example, if you create a database named `楮' on a server whose
operating system does not support CJK in directory names, MySQL creates
a directory named `@0w@00a5@00ae'. which is just a fancy way of
encoding `E6A5AE'--that is, the Unicode hexadecimal representation for
the `楮' character. However, if you run a *Note `SHOW DATABASES':
show-databases. statement, you can see that the database is listed as
`楮'.

*B.11.19: ** Where can I find translations of the MySQL Manual into
Chinese, Japanese, and Korean?  *

A Simplified Chinese version of the Manual, current for MySQL 5.1.12,
can be found at `http://dev.mysql.com/doc/'. The Japanese translation
of the MySQL 4.1 manual can be downloaded from
`http://dev.mysql.com/doc/'.

*B.11.20: ** Where can I get help with CJK and related issues in MySQL?
*

The following resources are available:

   * A listing of MySQL user groups can be found at
     `http://dev.mysql.com/user-groups/'.

   * View feature requests relating to character set issues at
     `http://tinyurl.com/y6xcuf'.

   * Visit the MySQL Collation Unicode Forum. We are also in the
     process of adding foreign-language forums at
     `http://forums.mysql.com/'.


File: manual.info,  Node: faqs-connectors-apis,  Next: faqs-replication,  Prev: faqs-cjk,  Up: faqs

B.12 MySQL 5.0 FAQ: Connectors & APIs
=====================================

For common questions, issues, and answers relating to the MySQL
Connectors and other APIs, see the following areas of the Manual:

   * *Note c-api-problems::

   * *Note apis-php-problems::

   * *Note connector-odbc-usagenotes::

   * *Note connector-net-programming::

   * *Note connector-j-usagenotes::

   * *Note connector-mxj-usagenotes::


File: manual.info,  Node: faqs-replication,  Next: faqs-mysql-drbd-heartbeat,  Prev: faqs-connectors-apis,  Up: faqs

B.13 MySQL 5.0 FAQ: Replication
===============================

For answers to common queries and question regarding Replication within
MySQL, see *Note replication-faq::.


File: manual.info,  Node: faqs-mysql-drbd-heartbeat,  Prev: faqs-replication,  Up: faqs

B.14 MySQL 5.0 FAQ: MySQL, DRBD, and Heartbeat
==============================================

* Menu:

* faqs-drbd::                    Distributed Replicated Block Device (DRBD)
* drbd-linux-heartbeat::         Linux Heartbeat
* drbd-architecture::            DRBD Architecture
* drbd-mysql-replication-scale::  DRBD and MySQL Replication
* drbd-file-systems::            DRBD and File Systems
* drbd-lvm::                     DRBD and LVM
* drbd-virtualization::          DRBD and Virtualization
* drbd-security::                DRBD and Security
* drbd-system-requirements::     DRBD and System Requirements
* drbd-support-consulting::      DRBD and Support and Consulting


File: manual.info,  Node: faqs-drbd,  Next: drbd-linux-heartbeat,  Prev: faqs-mysql-drbd-heartbeat,  Up: faqs-mysql-drbd-heartbeat

B.14.1 Distributed Replicated Block Device (DRBD)
-------------------------------------------------

In the following section, we provide answers to questions that are most
frequently asked about Distributed Replicated Block Device (DRBD).

*Questions*
   * B.14.1.1: What is DRBD?

   * B.14.1.2: What are `Block Devices'?

   * B.14.1.3: How is DRBD licensed?

   * B.14.1.4: Where can I download DRBD?

   * B.14.1.5: If I find a bug in DRBD, to whom do I submit the issue?

   * B.14.1.6: Where can I get more technical and business information
     concerning MySQL and DRBD?

*Questions and Answers* *B.14.1.1: ** What is DRBD?  *

DRBD is an acronym for Distributed Replicated Block Device. DRBD is an
open source Linux kernel block device which leverages synchronous
replication to achieve a consistent view of data between two systems,
typically an Active and Passive system.  DRBD currently supports all
the major flavors of Linux and comes bundled in several major Linux
distributions. The DRBD project is maintained by LINBIT
(http://www.drbd.org/).

*B.14.1.2: ** What are `Block Devices'?  *

A _block device_ is the type of device used to represent storage in the
Linux Kernel. All physical disk devices present a block device
interface. Additionally, virtual disk systems like LVM or DRBD present
a block device interface.  In this way, the file system or other
software that might want to access a disk device can be used with any
number of real or virtual devices without having to know anything about
their underlying implementation details.

*B.14.1.3: ** How is DRBD licensed?  *

DRBD is licensed under the GPL.

*B.14.1.4: ** Where can I download DRBD?  *

Please see `http://www.drbd.org/download/packages/'.

*B.14.1.5: ** If I find a bug in DRBD, to whom do I submit the issue?  *

Bug reports should be submitted to the DRBD mailing list. Please see
`http://lists.linbit.com/'.

*B.14.1.6: ** Where can I get more technical and business information
concerning MySQL and DRBD?  *

Please visit `http://mysql.com/drbd/'.


File: manual.info,  Node: drbd-linux-heartbeat,  Next: drbd-architecture,  Prev: faqs-drbd,  Up: faqs-mysql-drbd-heartbeat

B.14.2 Linux Heartbeat
----------------------

In the following section, we provide answers to questions that are most
frequently asked about Linux Heartbeat.

*Questions*
   * B.14.2.1: How is Linux Heartbeat licensed?

   * B.14.2.2: Where can I download Linux Heartbeat?

   * B.14.2.3: If I find a bug with Linux Heartbeat, to whom do I
     submit the issue?

*Questions and Answers* *B.14.2.1: ** How is Linux Heartbeat licensed?
*

Linux Heartbeat is licensed under the GPL.

*B.14.2.2: ** Where can I download Linux Heartbeat?  *

Please see `http://linux-ha.org/download/index.html'.

*B.14.2.3: ** If I find a bug with Linux Heartbeat, to whom do I submit
the issue?  *

Bug reports should be submitted to
`http://www.linux-ha.org/ClusterResourceManager/BugReports'.


File: manual.info,  Node: drbd-architecture,  Next: drbd-mysql-replication-scale,  Prev: drbd-linux-heartbeat,  Up: faqs-mysql-drbd-heartbeat

B.14.3 DRBD Architecture
------------------------

In the following section, we provide answers to questions that are most
frequently asked about DRBD Architecture.

*Questions*
   * B.14.3.1: Is an Active/Active option available for MySQL with DRBD?

   * B.14.3.2: What MySQL storage engines are supported with DRBD?

   * B.14.3.3: How long does a failover take?

   * B.14.3.4: How long does it take to resynchronize data after a
     failure?

   * B.14.3.5: Are there any situations where you shouldn't use DRBD?

   * B.14.3.6: Are there any limitations to DRBD?

   * B.14.3.7: Where can I find more information on sample
     architectures?

*Questions and Answers* *B.14.3.1: ** Is an Active/Active option
available for MySQL with DRBD?  *

Currently, MySQL does not support Active/Active configurations using
DRBD `out of the box'.

*B.14.3.2: ** What MySQL storage engines are supported with DRBD?  *

All of the MySQL transactional storage engines are supported by DRBD,
including InnoDB and Falcon. For archived or read-only data, MyISAM or
Archive can also be used.

*B.14.3.3: ** How long does a failover take?  *

Failover time is dependent on many things, some of which are
configurable. After activating the passive host, MySQL will have to
start and run a normal recovery process. If the InnoDB log files have
been configured to a large size and there was heavy write traffic, this
may take a reasonably long period of time.  However, under normal
circumstances, failover tends to take less than a minute.

*B.14.3.4: ** How long does it take to resynchronize data after a
failure?  *

Resynchronization time depends on how long the two machines are out of
communication and how much data was written during that period of time.
Resynchronization time is a function of data to be synced, network
speed and disk speed. DRBD maintains a bitmap of changed blocks on the
primary machine, so only those blocks that have changed will need to be
transferred.

*B.14.3.5: ** Are there any situations where you shouldn't use DRBD?  *

See When Not To Use DRBD
(http://fghaas.wordpress.com/2007/06/26/when-not-to-use-drbd/).

*B.14.3.6: ** Are there any limitations to DRBD?  *

See DRBD limitations (or are they?)
(http://fghaas.wordpress.com/2007/06/18/drbd-limitations-or-are-they/).

*B.14.3.7: ** Where can I find more information on sample architectures?
*

For an example of a Heartbeat R1-compatible resource configuration
involving a MySQL database backed by DRBD, see DRBD User's Guide
(http://www.drbd.org/users-guide/s-heartbeat-r1.html).

For an example of the same DRBD-backed configuration for a MySQL
database in a Heartbeat CRM cluster, see DRBD User's Guide
(http://www.drbd.org/users-guide/s-heartbeat-crm.html).


File: manual.info,  Node: drbd-mysql-replication-scale,  Next: drbd-file-systems,  Prev: drbd-architecture,  Up: faqs-mysql-drbd-heartbeat

B.14.4 DRBD and MySQL Replication
---------------------------------

In the following section, we provide answers to questions that are most
frequently asked about MySQL Replication Scale-out.

*Questions*
   * B.14.4.1: What is the difference between MySQL Cluster and DRBD?

   * B.14.4.2: What is the difference between MySQL Replication and
     DRBD?

   * B.14.4.3: How can I combine MySQL Replication scale-out with DRBD?

*Questions and Answers* *B.14.4.1: ** What is the difference between
MySQL Cluster and DRBD?  *

Both MySQL Cluster and DRBD replicate data synchronously. MySQL Cluster
leverages a shared-nothing storage architecture in which the cluster
can be architected beyond an Active/Passive configuration. DRBD
operates at a much lower level within the `stack', at the disk I/O
level. For a comparison of various high availability features between
these two options, please refer to *Note ha-overview::.

*B.14.4.2: ** What is the difference between MySQL Replication and DRBD?
*

MySQL Replication replicates data asynchronously while DRBD replicates
data synchronously. Also, MySQL Replication replicates MySQL
statements, while DRBD replicates the underlying block device that
stores the MySQL data files. For a comparison of various high
availability features between these two options, please refer to the
high availability comparison grid, *Note ha-overview::.

*B.14.4.3: ** How can I combine MySQL Replication scale-out with DRBD?
*

MySQL Replication is typically deployed in a Master to many Slaves
configuration. In this configuration, having many Slaves provides read
scalability. DRBD is used to provide high-availability for the Master
MySQL Server in an Active/Passive configuration. This provides for
automatic failover, safeguards against data loss, and automatically
synchronizes the failed MySQL Master after a failover.

The most likely scenario in which MySQL Replication scale-out can be
leveraged with DRBD is in the form of attaching replicated MySQL
`read-slaves' off of the Active-Master MySQL Server. Since DRBD
replicates an entire block device, master information such as the
binary logs are also replicated. In this way, all of the slaves can
attach to the Virtual IP Address managed by Linux Heartbeat. In the
event of a failure, the asynchronous nature of MySQL Replication allows
the slaves to continue with the new Active machine as their master with
no intervention needed.

FIGURE GOES HERE: Active-Master MySQL Server


File: manual.info,  Node: drbd-file-systems,  Next: drbd-lvm,  Prev: drbd-mysql-replication-scale,  Up: faqs-mysql-drbd-heartbeat

B.14.5 DRBD and File Systems
----------------------------

In the following section, we provide answers to questions that are most
frequently asked about DRBD and file systems.

*Questions*
   * B.14.5.1: Can XFS be used with DRBD?

*Questions and Answers* *B.14.5.1: ** Can XFS be used with DRBD?  *

Yes. XFS uses dynamic block size, thus DRBD 0.7 or later is needed.


File: manual.info,  Node: drbd-lvm,  Next: drbd-virtualization,  Prev: drbd-file-systems,  Up: faqs-mysql-drbd-heartbeat

B.14.6 DRBD and LVM
-------------------

In the following section, we provide answers to questions that are most
frequently asked about DRBD and LVM.

*Questions*
   * B.14.6.1: Can I use DRBD on top of LVM?

   * B.14.6.2: Can I use LVM on top of DRBD?

   * B.14.6.3: Can I use DRBD on top of LVM while at the same time
     running LVM on top of that DRBD?

*Questions and Answers* *B.14.6.1: ** Can I use DRBD on top of LVM?  *

Yes, DRBD supports on-line resizing. If you enlarge your logical volume
that acts as a backing device for DRBD, you can enlarge DRBD itself
too, and of course your file system if it supports resizing.

*B.14.6.2: ** Can I use LVM on top of DRBD?  *

Yes, you can use DRBD as a Physical Volume (PV) for LVM.  Depending on
the default LVM configuration shipped with your distribution, you may
need to add the `/dev/drbd*' device files to the `filter' option in your
`lvm.conf' so LVM scans your DRBDs for PV signatures.

*B.14.6.3: ** Can I use DRBD on top of LVM while at the same time
running LVM on top of that DRBD?  *

This requires careful tuning of your LVM configuration to avoid
duplicate PV scans, but yes, it is possible.


File: manual.info,  Node: drbd-virtualization,  Next: drbd-security,  Prev: drbd-lvm,  Up: faqs-mysql-drbd-heartbeat

B.14.7 DRBD and Virtualization
------------------------------

In the following section, we provide answers to questions that are most
frequently asked about DRBD and virtualization.

*Questions*
   * B.14.7.1: Can I use DRBD with OpenVZ?

   * B.14.7.2: Can I use DRBD with Xen or KVM?

*Questions and Answers* *B.14.7.1: ** Can I use DRBD with OpenVZ?  *

See `http://wiki.openvz.org/HA_cluster_with_DRBD_and_Heartbeat'.

*B.14.7.2: ** Can I use DRBD with Xen or KVM?  *

Yes. If you are looking for professional consultancy or expert
commercial support for Xen- or KVM-based virtualization clusters with
DRBD, contact LINBIT (`http://www.linbit.com').


File: manual.info,  Node: drbd-security,  Next: drbd-system-requirements,  Prev: drbd-virtualization,  Up: faqs-mysql-drbd-heartbeat

B.14.8 DRBD and Security
------------------------

In the following section, we provide answers to questions that are most
frequently asked about DRBD and security.

*Questions*
   * B.14.8.1: Can I encrypt/compress the exchanged data?

   * B.14.8.2: Does DRBD do mutual node authentication?

*Questions and Answers* *B.14.8.1: ** Can I encrypt/compress the
exchanged data?  *

Yes. But there is no option within DRBD to allow for this.  You'll need
to leverage a VPN and the network layer should do the rest.

*B.14.8.2: ** Does DRBD do mutual node authentication?  *

Yes, starting with DRBD 8 shared-secret mutual node authentication is
supported.


File: manual.info,  Node: drbd-system-requirements,  Next: drbd-support-consulting,  Prev: drbd-security,  Up: faqs-mysql-drbd-heartbeat

B.14.9 DRBD and System Requirements
-----------------------------------

In the following section, we provide answers to questions that are most
frequently asked about DRBD and System Requirements.

*Questions*
   * B.14.9.1: What other packages besides DRBD are required?

   * B.14.9.2: How many machines are required to set up DRBD?

   * B.14.9.3: Does DRBD only run on Linux?

*Questions and Answers* *B.14.9.1: ** What other packages besides DRBD
are required?  *

When using pre-built binary packages, none except a matching kernel,
plus packages for `glibc' and your favorite shell. When compiling DRBD
from source additional prerequisite packages may be required. They
include but are not limited to:

   * glib-devel

   * openssl

   * devel

   * libgcrypt-devel

   * glib2-devel

   * pkgconfig

   * ncurses-devel

   * rpm-build

   * rpm-devel

   * redhat-rpm-config

   * gcc

   * gcc-c++

   * bison

   * flex

   * gnutls-devel

   * lm_sensors-devel

   * net-snmp-devel

   * python-devel

   * bzip2-devel

   * libselinux-devel

   * perl-DBI

   * libnet

Pre-built x86 and x86_64 packages for specific kernel versions are
available with a support subscription from LINBIT. Please note that if
the kernel is upgraded, DRBD must be as well.

*B.14.9.2: ** How many machines are required to set up DRBD?  *

Two machines are required to achieve the minimum degree of high
availability. Although at any one given point in time one will be
primary and one will be secondary, it is better to consider the
machines as part of a mirrored pair without a `natural' primary machine.

*B.14.9.3: ** Does DRBD only run on Linux?  *

DRBD is a Linux Kernel Module, and can work with many popular Linux
distributions. DRBD is currently not available for non-Linux operating
systems.


File: manual.info,  Node: drbd-support-consulting,  Prev: drbd-system-requirements,  Up: faqs-mysql-drbd-heartbeat

B.14.10 DRBD and Support and Consulting
---------------------------------------

In the following section, we provide answers to questions that are most
frequently asked about DRBD and resources.

*Questions*
   * B.14.10.1: Does MySQL offer professional consulting to help with
     designing a DRBD system?

   * B.14.10.2: Does MySQL offer support for DRBD and Linux Heartbeat
     from MySQL?

   * B.14.10.3: Are pre-built binaries or RPMs available?

   * B.14.10.4: Does MySQL have documentation to help me with the
     installation and configuration of DRBD and Linux Heartbeat?

   * B.14.10.5: Is there a dedicated discussion forum for MySQL
     High-Availability?

   * B.14.10.6: Where can I get more information about MySQL for DRBD?

*Questions and Answers* *B.14.10.1: ** Does MySQL offer professional
consulting to help with designing a DRBD system?  *

Yes. MySQL offers consulting for the design, installation,
configuration, and monitoring of high availability DRBD. For more
information concerning a High Availability Jumpstart, please see:
http://www.mysql.com/consulting/packaged/scaleout.html.

*B.14.10.2: ** Does MySQL offer support for DRBD and Linux Heartbeat
from MySQL?  *

Yes. Support for DRBD is available with an add-on subscription to MySQL
Enterprise called "DRBD for MySQL". For more information about support
options for DRBD see:
`http://mysql.com/products/enterprise/features.html'.

For the list of supported Linux distributions, please see:
http://www.mysql.com/support/supportedplatforms/enterprise.html.

*Note*:

DRBD is only available on Linux. DRBD is not available on Windows,
MacOS, Solaris, HPUX, AIX, FreeBSD, or other non-Linux platforms.

*B.14.10.3: ** Are pre-built binaries or RPMs available?  *

Yes. `DRBD for MySQL' is an add-on subscription to MySQL Enterprise,
which provides pre-built binaries for DRBD.  For more information, see:
`http://mysql.com/products/enterprise/features.html'.

*B.14.10.4: ** Does MySQL have documentation to help me with the
installation and configuration of DRBD and Linux Heartbeat?  *

For MySQL-specific DRBD documentation, see *Note ha-drbd::.

For general DRBD documentation, see DRBD User's Guide
(http://www.drbd.org/users-guide/).

*B.14.10.5: ** Is there a dedicated discussion forum for MySQL
High-Availability?  *

Yes, `http://forums.mysql.com/list.php?144'.

*B.14.10.6: ** Where can I get more information about MySQL for DRBD?  *

For more information about MySQL for DRBD, including a technical white
paper please see: http://www.mysql.com/products/enterprise/drbd.html.


File: manual.info,  Node: error-handling,  Next: news,  Prev: faqs,  Up: Top

Appendix C Errors, Error Codes, and Common Problems
***************************************************

* Menu:

* error-sources::                Sources of Error Information
* error-types::                  Types of Error Values
* error-messages-server::        Server Error Codes and Messages
* error-messages-client::        Client Error Codes and Messages
* problems::                     Problems and Common Errors

This appendix lists common problems and errors that may occur and
potential resolutions, in addition to listing the errors that may
appear when you call MySQL from any host language. The first section
covers problems and resolutions. Detailed information on errors is
provided: One list displays server error messages. Another list
displays client program messages.


File: manual.info,  Node: error-sources,  Next: error-types,  Prev: error-handling,  Up: error-handling

C.1 Sources of Error Information
================================

There are several sources of error information in MySQL:

   * Each SQL statement executed results in an error code, an SQLSTATE
     value, and an error message, as described in *Note error-types::.
     These errors are returned from the server side; see *Note
     error-messages-server::.

   * Errors can occur on the client side, usually involving problems
     communicating with the server; see *Note error-messages-client::.

   * SQL statement warning and error information is available through
     the *Note `SHOW WARNINGS': show-warnings. and *Note `SHOW ERRORS':
     show-errors. statements. The `warning_count' system variable
     indicates the number of errors, warnings, and notes. The
     `error_count' system variable indicates the number of errors. Its
     value excludes warnings and notes.

   * *Note `SHOW SLAVE STATUS': show-slave-status. statement output
     includes information about replication errors occurring on the
     slave side.

   * *Note `SHOW ENGINE INNODB STATUS': show-engine. statement output
     includes information about the most recent foreign key error if a
     *Note `CREATE TABLE': create-table. statement for an *Note
     `InnoDB': innodb-storage-engine. table fails.

   * The *Note `perror': perror. program provides information from the
     command line about error numbers. See *Note perror::.

Descriptions of server and client errors are provided later in this
Appendix. For information about errors related to *Note `InnoDB':
innodb-storage-engine, see *Note innodb-error-handling::.


File: manual.info,  Node: error-types,  Next: error-messages-server,  Prev: error-sources,  Up: error-handling

C.2 Types of Error Values
=========================

When an error occurs in MySQL, the server returns two types of error
values:

   * A MySQL-specific error code. This value is numeric. It is not
     portable to other database systems.

   * An SQLSTATE value. The value is a five-character string (for
     example, `'42S02''). The values are taken from ANSI SQL and ODBC
     and are more standardized.

A message string that provides a textual description of the error is
also available.

When an error occurs, the MySQL error code, SQLSTATE value, and message
string are available using C API functions:

   * MySQL error code: Call *Note `mysql_errno()': mysql-errno.

   * SQLSTATE value: Call *Note `mysql_sqlstate()': mysql-sqlstate.

   * Error message: Call *Note `mysql_error()': mysql-error.

For prepared statements, the corresponding error functions are *Note
`mysql_stmt_errno()': mysql-stmt-errno, *Note `mysql_stmt_sqlstate()':
mysql-stmt-sqlstate, and *Note `mysql_stmt_error()': mysql-stmt-error.
All error functions are described in *Note c::.

The number of errors, warnings, and notes for the previous statement
can be obtained by calling *Note `mysql_warning_count()':
mysql-warning-count. See *Note mysql-warning-count::.

The first two characters of an SQLSTATE value indicate the error class:

   * Class = `'00'' indicates success.

   * Class = `'01'' indicates a warning.

   * Class = `'02'' indicates `not found.' This is relevant within the
     context of cursors and is used to control what happens when a
     cursor reaches the end of a data set. This condition also occurs
     for `SELECT ... INTO VAR_LIST' statements that retrieve no rows.

   * Class > `'02'' indicates an exception.


File: manual.info,  Node: error-messages-server,  Next: error-messages-client,  Prev: error-types,  Up: error-handling

C.3 Server Error Codes and Messages
===================================

MySQL programs have access to several types of error information when
the server returns an error. For example, the *Note `mysql': mysql.
client program displays errors using the following format:

     shell> SELECT * FROM no_such_table;
     ERROR 1146 (42S02): Table 'test.no_such_table' doesn't exist

The message displayed contains three types of information:

   * A numeric error code (`1146'). This number is MySQL-specific and
     is not portable to other database systems.

   * A five-character SQLSTATE value (`'42S02'').  The values are taken
     from ANSI SQL and ODBC and are more standardized. Not all MySQL
     error numbers have corresponding SQLSTATE values. In these cases,
     `'HY000'' (general error) is used.

   * A message string that provides a textual description of the error.

For error checking, use error codes, not error messages. Error messages
do not change often, but it is possible. Also if the database
administrator changes the language setting, that affects the language
of error messages.

Error codes are stable across GA releases of a given MySQL series.
Before a series reaches GA status, new codes may still be under
development and subject to change.

Server error information comes from the following source files.  For
details about the way that error information is defined, see the MySQL
Internals manual, available at
`http://forge.mysql.com/wiki/MySQL_Internals'.

   * Error message information is listed in the `share/errmsg.txt' file.
     `%d' and `%s' represent numbers and strings, respectively, that
     are substituted into the Message values when they are displayed.

   * The Error values listed in `share/errmsg.txt' are used to generate
     the definitions in the `include/mysqld_error.h' and
     `include/mysqld_ername.h' MySQL source files.

   * The SQLSTATE values listed in `share/errmsg.txt' are used to
     generate the definitions in the `include/sql_state.h' MySQL source
     file.

Because updates are frequent, it is possible that those files will
contain additional error information not listed here.

   *  Error: `1000' SQLSTATE: `HY000' (`ER_HASHCHK')

     Message: hashchk

   *  Error: `1001' SQLSTATE: `HY000' (`ER_NISAMCHK')

     Message: isamchk

   *  Error: `1002' SQLSTATE: `HY000' (`ER_NO')

     Message: NO

   *  Error: `1003' SQLSTATE: `HY000' (`ER_YES')

     Message: YES

   *  Error: `1004' SQLSTATE: `HY000' (`ER_CANT_CREATE_FILE')

     Message: Can't create file '%s' (errno: %d)

   *  Error: `1005' SQLSTATE: `HY000' (`ER_CANT_CREATE_TABLE')

     Message: Can't create table '%s' (errno: %d)

   *  Error: `1006' SQLSTATE: `HY000' (`ER_CANT_CREATE_DB')

     Message: Can't create database '%s' (errno: %d)

   *  Error: `1007' SQLSTATE: `HY000' (`ER_DB_CREATE_EXISTS')

     Message: Can't create database '%s'; database exists

   *  Error: `1008' SQLSTATE: `HY000' (`ER_DB_DROP_EXISTS')

     Message: Can't drop database '%s'; database doesn't exist

   *  Error: `1009' SQLSTATE: `HY000' (`ER_DB_DROP_DELETE')

     Message: Error dropping database (can't delete '%s', errno: %d)

   *  Error: `1010' SQLSTATE: `HY000' (`ER_DB_DROP_RMDIR')

     Message: Error dropping database (can't rmdir '%s', errno: %d)

   *  Error: `1011' SQLSTATE: `HY000' (`ER_CANT_DELETE_FILE')

     Message: Error on delete of '%s' (errno: %d)

   *  Error: `1012' SQLSTATE: `HY000' (`ER_CANT_FIND_SYSTEM_REC')

     Message: Can't read record in system table

   *  Error: `1013' SQLSTATE: `HY000' (`ER_CANT_GET_STAT')

     Message: Can't get status of '%s' (errno: %d)

   *  Error: `1014' SQLSTATE: `HY000' (`ER_CANT_GET_WD')

     Message: Can't get working directory (errno: %d)

   *  Error: `1015' SQLSTATE: `HY000' (`ER_CANT_LOCK')

     Message: Can't lock file (errno: %d)

   *  Error: `1016' SQLSTATE: `HY000' (`ER_CANT_OPEN_FILE')

     Message: Can't open file: '%s' (errno: %d)

   *  Error: `1017' SQLSTATE: `HY000' (`ER_FILE_NOT_FOUND')

     Message: Can't find file: '%s' (errno: %d)

   *  Error: `1018' SQLSTATE: `HY000' (`ER_CANT_READ_DIR')

     Message: Can't read dir of '%s' (errno: %d)

   *  Error: `1019' SQLSTATE: `HY000' (`ER_CANT_SET_WD')

     Message: Can't change dir to '%s' (errno: %d)

   *  Error: `1020' SQLSTATE: `HY000' (`ER_CHECKREAD')

     Message: Record has changed since last read in table '%s'

   *  Error: `1021' SQLSTATE: `HY000' (`ER_DISK_FULL')

     Message: Disk full (%s); waiting for someone to free some space...

   *  Error: `1022' SQLSTATE: `23000' (`ER_DUP_KEY')

     Message: Can't write; duplicate key in table '%s'

   *  Error: `1023' SQLSTATE: `HY000' (`ER_ERROR_ON_CLOSE')

     Message: Error on close of '%s' (errno: %d)

   *  Error: `1024' SQLSTATE: `HY000' (`ER_ERROR_ON_READ')

     Message: Error reading file '%s' (errno: %d)

   *  Error: `1025' SQLSTATE: `HY000' (`ER_ERROR_ON_RENAME')

     Message: Error on rename of '%s' to '%s' (errno: %d)

   *  Error: `1026' SQLSTATE: `HY000' (`ER_ERROR_ON_WRITE')

     Message: Error writing file '%s' (errno: %d)

   *  Error: `1027' SQLSTATE: `HY000' (`ER_FILE_USED')

     Message: '%s' is locked against change

   *  Error: `1028' SQLSTATE: `HY000' (`ER_FILSORT_ABORT')

     Message: Sort aborted

   *  Error: `1029' SQLSTATE: `HY000' (`ER_FORM_NOT_FOUND')

     Message: View '%s' doesn't exist for '%s'

   *  Error: `1030' SQLSTATE: `HY000' (`ER_GET_ERRNO')

     Message: Got error %d from storage engine

   *  Error: `1031' SQLSTATE: `HY000' (`ER_ILLEGAL_HA')

     Message: Table storage engine for '%s' doesn't have this option

   *  Error: `1032' SQLSTATE: `HY000' (`ER_KEY_NOT_FOUND')

     Message: Can't find record in '%s'

   *  Error: `1033' SQLSTATE: `HY000' (`ER_NOT_FORM_FILE')

     Message: Incorrect information in file: '%s'

   *  Error: `1034' SQLSTATE: `HY000' (`ER_NOT_KEYFILE')

     Message: Incorrect key file for table '%s'; try to repair it

   *  Error: `1035' SQLSTATE: `HY000' (`ER_OLD_KEYFILE')

     Message: Old key file for table '%s'; repair it!

   *  Error: `1036' SQLSTATE: `HY000' (`ER_OPEN_AS_READONLY')

     Message: Table '%s' is read only

   *  Error: `1037' SQLSTATE: `HY001' (`ER_OUTOFMEMORY')

     Message: Out of memory; restart server and try again (needed %d
     bytes)

   *  Error: `1038' SQLSTATE: `HY001' (`ER_OUT_OF_SORTMEMORY')

     Message: Out of sort memory; increase server sort buffer size

   *  Error: `1039' SQLSTATE: `HY000' (`ER_UNEXPECTED_EOF')

     Message: Unexpected EOF found when reading file '%s' (errno: %d)

   *  Error: `1040' SQLSTATE: `08004' (`ER_CON_COUNT_ERROR')

     Message: Too many connections

   *  Error: `1041' SQLSTATE: `HY000' (`ER_OUT_OF_RESOURCES')

     Message: Out of memory; check if mysqld or some other process uses
     all available memory; if not, you may have to use 'ulimit' to
     allow mysqld to use more memory or you can add more swap space

   *  Error: `1042' SQLSTATE: `08S01' (`ER_BAD_HOST_ERROR')

     Message: Can't get hostname for your address

   *  Error: `1043' SQLSTATE: `08S01' (`ER_HANDSHAKE_ERROR')

     Message: Bad handshake

   *  Error: `1044' SQLSTATE: `42000' (`ER_DBACCESS_DENIED_ERROR')

     Message: Access denied for user '%s'@'%s' to database '%s'

   *  Error: `1045' SQLSTATE: `28000' (`ER_ACCESS_DENIED_ERROR')

     Message: Access denied for user '%s'@'%s' (using password: %s)

   *  Error: `1046' SQLSTATE: `3D000' (`ER_NO_DB_ERROR')

     Message: No database selected

   *  Error: `1047' SQLSTATE: `08S01' (`ER_UNKNOWN_COM_ERROR')

     Message: Unknown command

   *  Error: `1048' SQLSTATE: `23000' (`ER_BAD_NULL_ERROR')

     Message: Column '%s' cannot be null

   *  Error: `1049' SQLSTATE: `42000' (`ER_BAD_DB_ERROR')

     Message: Unknown database '%s'

   *  Error: `1050' SQLSTATE: `42S01' (`ER_TABLE_EXISTS_ERROR')

     Message: Table '%s' already exists

   *  Error: `1051' SQLSTATE: `42S02' (`ER_BAD_TABLE_ERROR')

     Message: Unknown table '%s'

   *  Error: `1052' SQLSTATE: `23000' (`ER_NON_UNIQ_ERROR')

     Message: Column '%s' in %s is ambiguous

   *  Error: `1053' SQLSTATE: `08S01' (`ER_SERVER_SHUTDOWN')

     Message: Server shutdown in progress

   *  Error: `1054' SQLSTATE: `42S22' (`ER_BAD_FIELD_ERROR')

     Message: Unknown column '%s' in '%s'

   *  Error: `1055' SQLSTATE: `42000' (`ER_WRONG_FIELD_WITH_GROUP')

     Message: '%s' isn't in GROUP BY

   *  Error: `1056' SQLSTATE: `42000' (`ER_WRONG_GROUP_FIELD')

     Message: Can't group on '%s'

   *  Error: `1057' SQLSTATE: `42000' (`ER_WRONG_SUM_SELECT')

     Message: Statement has sum functions and columns in same statement

   *  Error: `1058' SQLSTATE: `21S01' (`ER_WRONG_VALUE_COUNT')

     Message: Column count doesn't match value count

   *  Error: `1059' SQLSTATE: `42000' (`ER_TOO_LONG_IDENT')

     Message: Identifier name '%s' is too long

   *  Error: `1060' SQLSTATE: `42S21' (`ER_DUP_FIELDNAME')

     Message: Duplicate column name '%s'

   *  Error: `1061' SQLSTATE: `42000' (`ER_DUP_KEYNAME')

     Message: Duplicate key name '%s'

   *  Error: `1062' SQLSTATE: `23000' (`ER_DUP_ENTRY')

     Message: Duplicate entry '%s' for key %d

   *  Error: `1063' SQLSTATE: `42000' (`ER_WRONG_FIELD_SPEC')

     Message: Incorrect column specifier for column '%s'

   *  Error: `1064' SQLSTATE: `42000' (`ER_PARSE_ERROR')

     Message: %s near '%s' at line %d

   *  Error: `1065' SQLSTATE: `42000' (`ER_EMPTY_QUERY')

     Message: Query was empty

   *  Error: `1066' SQLSTATE: `42000' (`ER_NONUNIQ_TABLE')

     Message: Not unique table/alias: '%s'

   *  Error: `1067' SQLSTATE: `42000' (`ER_INVALID_DEFAULT')

     Message: Invalid default value for '%s'

   *  Error: `1068' SQLSTATE: `42000' (`ER_MULTIPLE_PRI_KEY')

     Message: Multiple primary key defined

   *  Error: `1069' SQLSTATE: `42000' (`ER_TOO_MANY_KEYS')

     Message: Too many keys specified; max %d keys allowed

   *  Error: `1070' SQLSTATE: `42000' (`ER_TOO_MANY_KEY_PARTS')

     Message: Too many key parts specified; max %d parts allowed

   *  Error: `1071' SQLSTATE: `42000' (`ER_TOO_LONG_KEY')

     Message: Specified key was too long; max key length is %d bytes

   *  Error: `1072' SQLSTATE: `42000' (`ER_KEY_COLUMN_DOES_NOT_EXITS')

     Message: Key column '%s' doesn't exist in table

   *  Error: `1073' SQLSTATE: `42000' (`ER_BLOB_USED_AS_KEY')

     Message: BLOB column '%s' can't be used in key specification with
     the used table type

   *  Error: `1074' SQLSTATE: `42000' (`ER_TOO_BIG_FIELDLENGTH')

     Message: Column length too big for column '%s' (max = %lu); use
     BLOB or TEXT instead

   *  Error: `1075' SQLSTATE: `42000' (`ER_WRONG_AUTO_KEY')

     Message: Incorrect table definition; there can be only one auto
     column and it must be defined as a key

   *  Error: `1076' SQLSTATE: `HY000' (`ER_READY')

     Message: %s: ready for connections. Version: '%s' socket: '%s'
     port: %d

   *  Error: `1077' SQLSTATE: `HY000' (`ER_NORMAL_SHUTDOWN')

     Message: %s: Normal shutdown

   *  Error: `1078' SQLSTATE: `HY000' (`ER_GOT_SIGNAL')

     Message: %s: Got signal %d. Aborting!

   *  Error: `1079' SQLSTATE: `HY000' (`ER_SHUTDOWN_COMPLETE')

     Message: %s: Shutdown complete

   *  Error: `1080' SQLSTATE: `08S01' (`ER_FORCING_CLOSE')

     Message: %s: Forcing close of thread %ld user: '%s'

   *  Error: `1081' SQLSTATE: `08S01' (`ER_IPSOCK_ERROR')

     Message: Can't create IP socket

   *  Error: `1082' SQLSTATE: `42S12' (`ER_NO_SUCH_INDEX')

     Message: Table '%s' has no index like the one used in CREATE
     INDEX; recreate the table

   *  Error: `1083' SQLSTATE: `42000' (`ER_WRONG_FIELD_TERMINATORS')

     Message: Field separator argument is not what is expected; check
     the manual

   *  Error: `1084' SQLSTATE: `42000' (`ER_BLOBS_AND_NO_TERMINATED')

     Message: You can't use fixed rowlength with BLOBs; please use
     'fields terminated by'

   *  Error: `1085' SQLSTATE: `HY000' (`ER_TEXTFILE_NOT_READABLE')

     Message: The file '%s' must be in the database directory or be
     readable by all

   *  Error: `1086' SQLSTATE: `HY000' (`ER_FILE_EXISTS_ERROR')

     Message: File '%s' already exists

   *  Error: `1087' SQLSTATE: `HY000' (`ER_LOAD_INFO')

     Message: Records: %ld Deleted: %ld Skipped: %ld Warnings: %ld

   *  Error: `1088' SQLSTATE: `HY000' (`ER_ALTER_INFO')

     Message: Records: %ld Duplicates: %ld

   *  Error: `1089' SQLSTATE: `HY000' (`ER_WRONG_SUB_KEY')

     Message: Incorrect sub part key; the used key part isn't a string,
     the used length is longer than the key part, or the storage engine
     doesn't support unique sub keys

   *  Error: `1090' SQLSTATE: `42000' (`ER_CANT_REMOVE_ALL_FIELDS')

     Message: You can't delete all columns with ALTER TABLE; use DROP
     TABLE instead

   *  Error: `1091' SQLSTATE: `42000' (`ER_CANT_DROP_FIELD_OR_KEY')

     Message: Can't DROP '%s'; check that column/key exists

   *  Error: `1092' SQLSTATE: `HY000' (`ER_INSERT_INFO')

     Message: Records: %ld Duplicates: %ld Warnings: %ld

   *  Error: `1093' SQLSTATE: `HY000' (`ER_UPDATE_TABLE_USED')

     Message: You can't specify target table '%s' for update in FROM
     clause

   *  Error: `1094' SQLSTATE: `HY000' (`ER_NO_SUCH_THREAD')

     Message: Unknown thread id: %lu

   *  Error: `1095' SQLSTATE: `HY000' (`ER_KILL_DENIED_ERROR')

     Message: You are not owner of thread %lu

   *  Error: `1096' SQLSTATE: `HY000' (`ER_NO_TABLES_USED')

     Message: No tables used

   *  Error: `1097' SQLSTATE: `HY000' (`ER_TOO_BIG_SET')

     Message: Too many strings for column %s and SET

   *  Error: `1098' SQLSTATE: `HY000' (`ER_NO_UNIQUE_LOGFILE')

     Message: Can't generate a unique log-filename %s.(1-999)

   *  Error: `1099' SQLSTATE: `HY000' (`ER_TABLE_NOT_LOCKED_FOR_WRITE')

     Message: Table '%s' was locked with a READ lock and can't be
     updated

   *  Error: `1100' SQLSTATE: `HY000' (`ER_TABLE_NOT_LOCKED')

     Message: Table '%s' was not locked with LOCK TABLES

   *  Error: `1101' SQLSTATE: `42000' (`ER_BLOB_CANT_HAVE_DEFAULT')

     Message: BLOB/TEXT column '%s' can't have a default value

   *  Error: `1102' SQLSTATE: `42000' (`ER_WRONG_DB_NAME')

     Message: Incorrect database name '%s'

   *  Error: `1103' SQLSTATE: `42000' (`ER_WRONG_TABLE_NAME')

     Message: Incorrect table name '%s'

   *  Error: `1104' SQLSTATE: `42000' (`ER_TOO_BIG_SELECT')

     Message: The SELECT would examine more than MAX_JOIN_SIZE rows;
     check your WHERE and use SET SQL_BIG_SELECTS=1 or SET
     SQL_MAX_JOIN_SIZE=# if the SELECT is okay

   *  Error: `1105' SQLSTATE: `HY000' (`ER_UNKNOWN_ERROR')

     Message: Unknown error

   *  Error: `1106' SQLSTATE: `42000' (`ER_UNKNOWN_PROCEDURE')

     Message: Unknown procedure '%s'

   *  Error: `1107' SQLSTATE: `42000'
     (`ER_WRONG_PARAMCOUNT_TO_PROCEDURE')

     Message: Incorrect parameter count to procedure '%s'

   *  Error: `1108' SQLSTATE: `HY000'
     (`ER_WRONG_PARAMETERS_TO_PROCEDURE')

     Message: Incorrect parameters to procedure '%s'

   *  Error: `1109' SQLSTATE: `42S02' (`ER_UNKNOWN_TABLE')

     Message: Unknown table '%s' in %s

   *  Error: `1110' SQLSTATE: `42000' (`ER_FIELD_SPECIFIED_TWICE')

     Message: Column '%s' specified twice

   *  Error: `1111' SQLSTATE: `HY000' (`ER_INVALID_GROUP_FUNC_USE')

     Message: Invalid use of group function

   *  Error: `1112' SQLSTATE: `42000' (`ER_UNSUPPORTED_EXTENSION')

     Message: Table '%s' uses an extension that doesn't exist in this
     MySQL version

   *  Error: `1113' SQLSTATE: `42000' (`ER_TABLE_MUST_HAVE_COLUMNS')

     Message: A table must have at least 1 column

   *  Error: `1114' SQLSTATE: `HY000' (`ER_RECORD_FILE_FULL')

     Message: The table '%s' is full

   *  Error: `1115' SQLSTATE: `42000' (`ER_UNKNOWN_CHARACTER_SET')

     Message: Unknown character set: '%s'

   *  Error: `1116' SQLSTATE: `HY000' (`ER_TOO_MANY_TABLES')

     Message: Too many tables; MySQL can only use %d tables in a join

   *  Error: `1117' SQLSTATE: `HY000' (`ER_TOO_MANY_FIELDS')

     Message: Too many columns

   *  Error: `1118' SQLSTATE: `42000' (`ER_TOO_BIG_ROWSIZE')

     Message: Row size too large. The maximum row size for the used
     table type, not counting BLOBs, is %ld. You have to change some
     columns to TEXT or BLOBs

   *  Error: `1119' SQLSTATE: `HY000' (`ER_STACK_OVERRUN')

     Message: Thread stack overrun: Used: %ld of a %ld stack. Use
     'mysqld -O thread_stack=#' to specify a bigger stack if needed

   *  Error: `1120' SQLSTATE: `42000' (`ER_WRONG_OUTER_JOIN')

     Message: Cross dependency found in OUTER JOIN; examine your ON
     conditions

   *  Error: `1121' SQLSTATE: `42000' (`ER_NULL_COLUMN_IN_INDEX')

     Message: Column '%s' is used with UNIQUE or INDEX but is not
     defined as NOT NULL

   *  Error: `1122' SQLSTATE: `HY000' (`ER_CANT_FIND_UDF')

     Message: Can't load function '%s'

   *  Error: `1123' SQLSTATE: `HY000' (`ER_CANT_INITIALIZE_UDF')

     Message: Can't initialize function '%s'; %s

   *  Error: `1124' SQLSTATE: `HY000' (`ER_UDF_NO_PATHS')

     Message: No paths allowed for shared library

   *  Error: `1125' SQLSTATE: `HY000' (`ER_UDF_EXISTS')

     Message: Function '%s' already exists

   *  Error: `1126' SQLSTATE: `HY000' (`ER_CANT_OPEN_LIBRARY')

     Message: Can't open shared library '%s' (errno: %d %s)

   *  Error: `1127' SQLSTATE: `HY000' (`ER_CANT_FIND_DL_ENTRY')

     Message: Can't find function '%s' in library

   *  Error: `1128' SQLSTATE: `HY000' (`ER_FUNCTION_NOT_DEFINED')

     Message: Function '%s' is not defined

   *  Error: `1129' SQLSTATE: `HY000' (`ER_HOST_IS_BLOCKED')

     Message: Host '%s' is blocked because of many connection errors;
     unblock with 'mysqladmin flush-hosts'

   *  Error: `1130' SQLSTATE: `HY000' (`ER_HOST_NOT_PRIVILEGED')

     Message: Host '%s' is not allowed to connect to this MySQL server

   *  Error: `1131' SQLSTATE: `42000' (`ER_PASSWORD_ANONYMOUS_USER')

     Message: You are using MySQL as an anonymous user and anonymous
     users are not allowed to change passwords

   *  Error: `1132' SQLSTATE: `42000' (`ER_PASSWORD_NOT_ALLOWED')

     Message: You must have privileges to update tables in the mysql
     database to be able to change passwords for others

   *  Error: `1133' SQLSTATE: `42000' (`ER_PASSWORD_NO_MATCH')

     Message: Can't find any matching row in the user table

   *  Error: `1134' SQLSTATE: `HY000' (`ER_UPDATE_INFO')

     Message: Rows matched: %ld Changed: %ld Warnings: %ld

   *  Error: `1135' SQLSTATE: `HY000' (`ER_CANT_CREATE_THREAD')

     Message: Can't create a new thread (errno %d); if you are not out
     of available memory, you can consult the manual for a possible
     OS-dependent bug

   *  Error: `1136' SQLSTATE: `21S01' (`ER_WRONG_VALUE_COUNT_ON_ROW')

     Message: Column count doesn't match value count at row %ld

   *  Error: `1137' SQLSTATE: `HY000' (`ER_CANT_REOPEN_TABLE')

     Message: Can't reopen table: '%s'

   *  Error: `1138' SQLSTATE: `22004' (`ER_INVALID_USE_OF_NULL')

     Message: Invalid use of NULL value

   *  Error: `1139' SQLSTATE: `42000' (`ER_REGEXP_ERROR')

     Message: Got error '%s' from regexp

   *  Error: `1140' SQLSTATE: `42000'
     (`ER_MIX_OF_GROUP_FUNC_AND_FIELDS')

     Message: Mixing of GROUP columns (MIN(),MAX(),COUNT(),...) with no
     GROUP columns is illegal if there is no GROUP BY clause

   *  Error: `1141' SQLSTATE: `42000' (`ER_NONEXISTING_GRANT')

     Message: There is no such grant defined for user '%s' on host '%s'

   *  Error: `1142' SQLSTATE: `42000' (`ER_TABLEACCESS_DENIED_ERROR')

     Message: %s command denied to user '%s'@'%s' for table '%s'

   *  Error: `1143' SQLSTATE: `42000' (`ER_COLUMNACCESS_DENIED_ERROR')

     Message: %s command denied to user '%s'@'%s' for column '%s' in
     table '%s'

   *  Error: `1144' SQLSTATE: `42000' (`ER_ILLEGAL_GRANT_FOR_TABLE')

     Message: Illegal GRANT/REVOKE command; please consult the manual
     to see which privileges can be used

   *  Error: `1145' SQLSTATE: `42000' (`ER_GRANT_WRONG_HOST_OR_USER')

     Message: The host or user argument to GRANT is too long

   *  Error: `1146' SQLSTATE: `42S02' (`ER_NO_SUCH_TABLE')

     Message: Table '%s.%s' doesn't exist

   *  Error: `1147' SQLSTATE: `42000' (`ER_NONEXISTING_TABLE_GRANT')

     Message: There is no such grant defined for user '%s' on host '%s'
     on table '%s'

   *  Error: `1148' SQLSTATE: `42000' (`ER_NOT_ALLOWED_COMMAND')

     Message: The used command is not allowed with this MySQL version

   *  Error: `1149' SQLSTATE: `42000' (`ER_SYNTAX_ERROR')

     Message: You have an error in your SQL syntax; check the manual
     that corresponds to your MySQL server version for the right syntax
     to use

   *  Error: `1150' SQLSTATE: `HY000' (`ER_DELAYED_CANT_CHANGE_LOCK')

     Message: Delayed insert thread couldn't get requested lock for
     table %s

   *  Error: `1151' SQLSTATE: `HY000' (`ER_TOO_MANY_DELAYED_THREADS')

     Message: Too many delayed threads in use

   *  Error: `1152' SQLSTATE: `08S01' (`ER_ABORTING_CONNECTION')

     Message: Aborted connection %ld to db: '%s' user: '%s' (%s)

   *  Error: `1153' SQLSTATE: `08S01' (`ER_NET_PACKET_TOO_LARGE')

     Message: Got a packet bigger than 'max_allowed_packet' bytes

   *  Error: `1154' SQLSTATE: `08S01' (`ER_NET_READ_ERROR_FROM_PIPE')

     Message: Got a read error from the connection pipe

   *  Error: `1155' SQLSTATE: `08S01' (`ER_NET_FCNTL_ERROR')

     Message: Got an error from fcntl()

   *  Error: `1156' SQLSTATE: `08S01' (`ER_NET_PACKETS_OUT_OF_ORDER')

     Message: Got packets out of order

   *  Error: `1157' SQLSTATE: `08S01' (`ER_NET_UNCOMPRESS_ERROR')

     Message: Couldn't uncompress communication packet

   *  Error: `1158' SQLSTATE: `08S01' (`ER_NET_READ_ERROR')

     Message: Got an error reading communication packets

   *  Error: `1159' SQLSTATE: `08S01' (`ER_NET_READ_INTERRUPTED')

     Message: Got timeout reading communication packets

   *  Error: `1160' SQLSTATE: `08S01' (`ER_NET_ERROR_ON_WRITE')

     Message: Got an error writing communication packets

   *  Error: `1161' SQLSTATE: `08S01' (`ER_NET_WRITE_INTERRUPTED')

     Message: Got timeout writing communication packets

   *  Error: `1162' SQLSTATE: `42000' (`ER_TOO_LONG_STRING')

     Message: Result string is longer than 'max_allowed_packet' bytes

   *  Error: `1163' SQLSTATE: `42000' (`ER_TABLE_CANT_HANDLE_BLOB')

     Message: The used table type doesn't support BLOB/TEXT columns

   *  Error: `1164' SQLSTATE: `42000'
     (`ER_TABLE_CANT_HANDLE_AUTO_INCREMENT')

     Message: The used table type doesn't support AUTO_INCREMENT columns

   *  Error: `1165' SQLSTATE: `HY000' (`ER_DELAYED_INSERT_TABLE_LOCKED')

     Message: INSERT DELAYED can't be used with table '%s' because it
     is locked with LOCK TABLES

   *  Error: `1166' SQLSTATE: `42000' (`ER_WRONG_COLUMN_NAME')

     Message: Incorrect column name '%s'

   *  Error: `1167' SQLSTATE: `42000' (`ER_WRONG_KEY_COLUMN')

     Message: The used storage engine can't index column '%s'

   *  Error: `1168' SQLSTATE: `HY000' (`ER_WRONG_MRG_TABLE')

     Message: Unable to open underlying table which is differently
     defined or of non-MyISAM type or doesn't exist

   *  Error: `1169' SQLSTATE: `23000' (`ER_DUP_UNIQUE')

     Message: Can't write, because of unique constraint, to table '%s'

   *  Error: `1170' SQLSTATE: `42000' (`ER_BLOB_KEY_WITHOUT_LENGTH')

     Message: BLOB/TEXT column '%s' used in key specification without a
     key length

   *  Error: `1171' SQLSTATE: `42000' (`ER_PRIMARY_CANT_HAVE_NULL')

     Message: All parts of a PRIMARY KEY must be NOT NULL; if you need
     NULL in a key, use UNIQUE instead

   *  Error: `1172' SQLSTATE: `42000' (`ER_TOO_MANY_ROWS')

     Message: Result consisted of more than one row

   *  Error: `1173' SQLSTATE: `42000' (`ER_REQUIRES_PRIMARY_KEY')

     Message: This table type requires a primary key

   *  Error: `1174' SQLSTATE: `HY000' (`ER_NO_RAID_COMPILED')

     Message: This version of MySQL is not compiled with RAID support

   *  Error: `1175' SQLSTATE: `HY000'
     (`ER_UPDATE_WITHOUT_KEY_IN_SAFE_MODE')

     Message: You are using safe update mode and you tried to update a
     table without a WHERE that uses a KEY column

   *  Error: `1176' SQLSTATE: `HY000' (`ER_KEY_DOES_NOT_EXITS')

     Message: Key '%s' doesn't exist in table '%s'

   *  Error: `1177' SQLSTATE: `42000' (`ER_CHECK_NO_SUCH_TABLE')

     Message: Can't open table

   *  Error: `1178' SQLSTATE: `42000' (`ER_CHECK_NOT_IMPLEMENTED')

     Message: The storage engine for the table doesn't support %s

   *  Error: `1179' SQLSTATE: `25000'
     (`ER_CANT_DO_THIS_DURING_AN_TRANSACTION')

     Message: You are not allowed to execute this command in a
     transaction

   *  Error: `1180' SQLSTATE: `HY000' (`ER_ERROR_DURING_COMMIT')

     Message: Got error %d during COMMIT

   *  Error: `1181' SQLSTATE: `HY000' (`ER_ERROR_DURING_ROLLBACK')

     Message: Got error %d during ROLLBACK

   *  Error: `1182' SQLSTATE: `HY000' (`ER_ERROR_DURING_FLUSH_LOGS')

     Message: Got error %d during FLUSH_LOGS

   *  Error: `1183' SQLSTATE: `HY000' (`ER_ERROR_DURING_CHECKPOINT')

     Message: Got error %d during CHECKPOINT

   *  Error: `1184' SQLSTATE: `08S01' (`ER_NEW_ABORTING_CONNECTION')

     Message: Aborted connection %ld to db: '%s' user: '%s' host: '%s'
     (%s)

   *  Error: `1185' SQLSTATE: `HY000' (`ER_DUMP_NOT_IMPLEMENTED')

     Message: The storage engine for the table does not support binary
     table dump

   *  Error: `1186' SQLSTATE: `HY000' (`ER_FLUSH_MASTER_BINLOG_CLOSED')

     Message: Binlog closed, cannot RESET MASTER

   *  Error: `1187' SQLSTATE: `HY000' (`ER_INDEX_REBUILD')

     Message: Failed rebuilding the index of dumped table '%s'

   *  Error: `1188' SQLSTATE: `HY000' (`ER_MASTER')

     Message: Error from master: '%s'

   *  Error: `1189' SQLSTATE: `08S01' (`ER_MASTER_NET_READ')

     Message: Net error reading from master

   *  Error: `1190' SQLSTATE: `08S01' (`ER_MASTER_NET_WRITE')

     Message: Net error writing to master

   *  Error: `1191' SQLSTATE: `HY000' (`ER_FT_MATCHING_KEY_NOT_FOUND')

     Message: Can't find FULLTEXT index matching the column list

   *  Error: `1192' SQLSTATE: `HY000' (`ER_LOCK_OR_ACTIVE_TRANSACTION')

     Message: Can't execute the given command because you have active
     locked tables or an active transaction

   *  Error: `1193' SQLSTATE: `HY000' (`ER_UNKNOWN_SYSTEM_VARIABLE')

     Message: Unknown system variable '%s'

   *  Error: `1194' SQLSTATE: `HY000' (`ER_CRASHED_ON_USAGE')

     Message: Table '%s' is marked as crashed and should be repaired

   *  Error: `1195' SQLSTATE: `HY000' (`ER_CRASHED_ON_REPAIR')

     Message: Table '%s' is marked as crashed and last (automatic?)
     repair failed

   *  Error: `1196' SQLSTATE: `HY000'
     (`ER_WARNING_NOT_COMPLETE_ROLLBACK')

     Message: Some non-transactional changed tables couldn't be rolled
     back

   *  Error: `1197' SQLSTATE: `HY000' (`ER_TRANS_CACHE_FULL')

     Message: Multi-statement transaction required more than
     'max_binlog_cache_size' bytes of storage; increase this mysqld
     variable and try again

   *  Error: `1198' SQLSTATE: `HY000' (`ER_SLAVE_MUST_STOP')

     Message: This operation cannot be performed with a running slave;
     run STOP SLAVE first

   *  Error: `1199' SQLSTATE: `HY000' (`ER_SLAVE_NOT_RUNNING')

     Message: This operation requires a running slave; configure slave
     and do START SLAVE

   *  Error: `1200' SQLSTATE: `HY000' (`ER_BAD_SLAVE')

     Message: The server is not configured as slave; fix in config file
     or with CHANGE MASTER TO

   *  Error: `1201' SQLSTATE: `HY000' (`ER_MASTER_INFO')

     Message: Could not initialize master info structure; more error
     messages can be found in the MySQL error log

   *  Error: `1202' SQLSTATE: `HY000' (`ER_SLAVE_THREAD')

     Message: Could not create slave thread; check system resources

   *  Error: `1203' SQLSTATE: `42000' (`ER_TOO_MANY_USER_CONNECTIONS')

     Message: User %s already has more than 'max_user_connections'
     active connections

   *  Error: `1204' SQLSTATE: `HY000' (`ER_SET_CONSTANTS_ONLY')

     Message: You may only use constant expressions with SET

   *  Error: `1205' SQLSTATE: `HY000' (`ER_LOCK_WAIT_TIMEOUT')

     Message: Lock wait timeout exceeded; try restarting transaction

   *  Error: `1206' SQLSTATE: `HY000' (`ER_LOCK_TABLE_FULL')

     Message: The total number of locks exceeds the lock table size

   *  Error: `1207' SQLSTATE: `25000' (`ER_READ_ONLY_TRANSACTION')

     Message: Update locks cannot be acquired during a READ UNCOMMITTED
     transaction

   *  Error: `1208' SQLSTATE: `HY000' (`ER_DROP_DB_WITH_READ_LOCK')

     Message: DROP DATABASE not allowed while thread is holding global
     read lock

   *  Error: `1209' SQLSTATE: `HY000' (`ER_CREATE_DB_WITH_READ_LOCK')

     Message: CREATE DATABASE not allowed while thread is holding
     global read lock

   *  Error: `1210' SQLSTATE: `HY000' (`ER_WRONG_ARGUMENTS')

     Message: Incorrect arguments to %s

   *  Error: `1211' SQLSTATE: `42000'
     (`ER_NO_PERMISSION_TO_CREATE_USER')

     Message: '%s'@'%s' is not allowed to create new users

   *  Error: `1212' SQLSTATE: `HY000'
     (`ER_UNION_TABLES_IN_DIFFERENT_DIR')

     Message: Incorrect table definition; all MERGE tables must be in
     the same database

   *  Error: `1213' SQLSTATE: `40001' (`ER_LOCK_DEADLOCK')

     Message: Deadlock found when trying to get lock; try restarting
     transaction

   *  Error: `1214' SQLSTATE: `HY000' (`ER_TABLE_CANT_HANDLE_FT')

     Message: The used table type doesn't support FULLTEXT indexes

   *  Error: `1215' SQLSTATE: `HY000' (`ER_CANNOT_ADD_FOREIGN')

     Message: Cannot add foreign key constraint

   *  Error: `1216' SQLSTATE: `23000' (`ER_NO_REFERENCED_ROW')

     Message: Cannot add or update a child row: a foreign key
     constraint fails

   *  Error: `1217' SQLSTATE: `23000' (`ER_ROW_IS_REFERENCED')

     Message: Cannot delete or update a parent row: a foreign key
     constraint fails

   *  Error: `1218' SQLSTATE: `08S01' (`ER_CONNECT_TO_MASTER')

     Message: Error connecting to master: %s

   *  Error: `1219' SQLSTATE: `HY000' (`ER_QUERY_ON_MASTER')

     Message: Error running query on master: %s

   *  Error: `1220' SQLSTATE: `HY000'
     (`ER_ERROR_WHEN_EXECUTING_COMMAND')

     Message: Error when executing command %s: %s

   *  Error: `1221' SQLSTATE: `HY000' (`ER_WRONG_USAGE')

     Message: Incorrect usage of %s and %s

   *  Error: `1222' SQLSTATE: `21000'
     (`ER_WRONG_NUMBER_OF_COLUMNS_IN_SELECT')

     Message: The used SELECT statements have a different number of
     columns

   *  Error: `1223' SQLSTATE: `HY000' (`ER_CANT_UPDATE_WITH_READLOCK')

     Message: Can't execute the query because you have a conflicting
     read lock

   *  Error: `1224' SQLSTATE: `HY000' (`ER_MIXING_NOT_ALLOWED')

     Message: Mixing of transactional and non-transactional tables is
     disabled

   *  Error: `1225' SQLSTATE: `HY000' (`ER_DUP_ARGUMENT')

     Message: Option '%s' used twice in statement

   *  Error: `1226' SQLSTATE: `42000' (`ER_USER_LIMIT_REACHED')

     Message: User '%s' has exceeded the '%s' resource (current value:
     %ld)

   *  Error: `1227' SQLSTATE: `42000'
     (`ER_SPECIFIC_ACCESS_DENIED_ERROR')

     Message: Access denied; you need the %s privilege for this
     operation

   *  Error: `1228' SQLSTATE: `HY000' (`ER_LOCAL_VARIABLE')

     Message: Variable '%s' is a SESSION variable and can't be used
     with SET GLOBAL

   *  Error: `1229' SQLSTATE: `HY000' (`ER_GLOBAL_VARIABLE')

     Message: Variable '%s' is a GLOBAL variable and should be set with
     SET GLOBAL

   *  Error: `1230' SQLSTATE: `42000' (`ER_NO_DEFAULT')

     Message: Variable '%s' doesn't have a default value

   *  Error: `1231' SQLSTATE: `42000' (`ER_WRONG_VALUE_FOR_VAR')

     Message: Variable '%s' can't be set to the value of '%s'

   *  Error: `1232' SQLSTATE: `42000' (`ER_WRONG_TYPE_FOR_VAR')

     Message: Incorrect argument type to variable '%s'

   *  Error: `1233' SQLSTATE: `HY000' (`ER_VAR_CANT_BE_READ')

     Message: Variable '%s' can only be set, not read

   *  Error: `1234' SQLSTATE: `42000' (`ER_CANT_USE_OPTION_HERE')

     Message: Incorrect usage/placement of '%s'

   *  Error: `1235' SQLSTATE: `42000' (`ER_NOT_SUPPORTED_YET')

     Message: This version of MySQL doesn't yet support '%s'

   *  Error: `1236' SQLSTATE: `HY000'
     (`ER_MASTER_FATAL_ERROR_READING_BINLOG')

     Message: Got fatal error %d: '%s' from master when reading data
     from binary log

   *  Error: `1237' SQLSTATE: `HY000' (`ER_SLAVE_IGNORED_TABLE')

     Message: Slave SQL thread ignored the query because of
     replicate-*-table rules

   *  Error: `1238' SQLSTATE: `HY000' (`ER_INCORRECT_GLOBAL_LOCAL_VAR')

     Message: Variable '%s' is a %s variable

   *  Error: `1239' SQLSTATE: `42000' (`ER_WRONG_FK_DEF')

     Message: Incorrect foreign key definition for '%s': %s

   *  Error: `1240' SQLSTATE: `HY000'
     (`ER_KEY_REF_DO_NOT_MATCH_TABLE_REF')

     Message: Key reference and table reference don't match

   *  Error: `1241' SQLSTATE: `21000' (`ER_OPERAND_COLUMNS')

     Message: Operand should contain %d column(s)

   *  Error: `1242' SQLSTATE: `21000' (`ER_SUBQUERY_NO_1_ROW')

     Message: Subquery returns more than 1 row

   *  Error: `1243' SQLSTATE: `HY000' (`ER_UNKNOWN_STMT_HANDLER')

     Message: Unknown prepared statement handler (%.*s) given to %s

   *  Error: `1244' SQLSTATE: `HY000' (`ER_CORRUPT_HELP_DB')

     Message: Help database is corrupt or does not exist

   *  Error: `1245' SQLSTATE: `HY000' (`ER_CYCLIC_REFERENCE')

     Message: Cyclic reference on subqueries

   *  Error: `1246' SQLSTATE: `HY000' (`ER_AUTO_CONVERT')

     Message: Converting column '%s' from %s to %s

   *  Error: `1247' SQLSTATE: `42S22' (`ER_ILLEGAL_REFERENCE')

     Message: Reference '%s' not supported (%s)

   *  Error: `1248' SQLSTATE: `42000' (`ER_DERIVED_MUST_HAVE_ALIAS')

     Message: Every derived table must have its own alias

   *  Error: `1249' SQLSTATE: `01000' (`ER_SELECT_REDUCED')

     Message: Select %u was reduced during optimization

   *  Error: `1250' SQLSTATE: `42000' (`ER_TABLENAME_NOT_ALLOWED_HERE')

     Message: Table '%s' from one of the SELECTs cannot be used in %s

   *  Error: `1251' SQLSTATE: `08004' (`ER_NOT_SUPPORTED_AUTH_MODE')

     Message: Client does not support authentication protocol requested
     by server; consider upgrading MySQL client

   *  Error: `1252' SQLSTATE: `42000' (`ER_SPATIAL_CANT_HAVE_NULL')

     Message: All parts of a SPATIAL index must be NOT NULL

   *  Error: `1253' SQLSTATE: `42000' (`ER_COLLATION_CHARSET_MISMATCH')

     Message: COLLATION '%s' is not valid for CHARACTER SET '%s'

   *  Error: `1254' SQLSTATE: `HY000' (`ER_SLAVE_WAS_RUNNING')

     Message: Slave is already running

   *  Error: `1255' SQLSTATE: `HY000' (`ER_SLAVE_WAS_NOT_RUNNING')

     Message: Slave already has been stopped

   *  Error: `1256' SQLSTATE: `HY000' (`ER_TOO_BIG_FOR_UNCOMPRESS')

     Message: Uncompressed data size too large; the maximum size is %d
     (probably, length of uncompressed data was corrupted)

   *  Error: `1257' SQLSTATE: `HY000' (`ER_ZLIB_Z_MEM_ERROR')

     Message: ZLIB: Not enough memory

   *  Error: `1258' SQLSTATE: `HY000' (`ER_ZLIB_Z_BUF_ERROR')

     Message: ZLIB: Not enough room in the output buffer (probably,
     length of uncompressed data was corrupted)

   *  Error: `1259' SQLSTATE: `HY000' (`ER_ZLIB_Z_DATA_ERROR')

     Message: ZLIB: Input data corrupted

   *  Error: `1260' SQLSTATE: `HY000' (`ER_CUT_VALUE_GROUP_CONCAT')

     Message: %d line(s) were cut by GROUP_CONCAT()

   *  Error: `1261' SQLSTATE: `01000' (`ER_WARN_TOO_FEW_RECORDS')

     Message: Row %ld doesn't contain data for all columns

   *  Error: `1262' SQLSTATE: `01000' (`ER_WARN_TOO_MANY_RECORDS')

     Message: Row %ld was truncated; it contained more data than there
     were input columns

   *  Error: `1263' SQLSTATE: `22004' (`ER_WARN_NULL_TO_NOTNULL')

     Message: Column was set to data type implicit default; NULL
     supplied for NOT NULL column '%s' at row %ld

   *  Error: `1264' SQLSTATE: `22003' (`ER_WARN_DATA_OUT_OF_RANGE')

     Message: Out of range value adjusted for column '%s' at row %ld

   *  Error: `1265' SQLSTATE: `01000' (`WARN_DATA_TRUNCATED')

     Message: Data truncated for column '%s' at row %ld

   *  Error: `1266' SQLSTATE: `HY000' (`ER_WARN_USING_OTHER_HANDLER')

     Message: Using storage engine %s for table '%s'

   *  Error: `1267' SQLSTATE: `HY000' (`ER_CANT_AGGREGATE_2COLLATIONS')

     Message: Illegal mix of collations (%s,%s) and (%s,%s) for
     operation '%s'

   *  Error: `1268' SQLSTATE: `HY000' (`ER_DROP_USER')

     Message: Cannot drop one or more of the requested users

   *  Error: `1269' SQLSTATE: `HY000' (`ER_REVOKE_GRANTS')

     Message: Can't revoke all privileges for one or more of the
     requested users

   *  Error: `1270' SQLSTATE: `HY000' (`ER_CANT_AGGREGATE_3COLLATIONS')

     Message: Illegal mix of collations (%s,%s), (%s,%s), (%s,%s) for
     operation '%s'

   *  Error: `1271' SQLSTATE: `HY000' (`ER_CANT_AGGREGATE_NCOLLATIONS')

     Message: Illegal mix of collations for operation '%s'

   *  Error: `1272' SQLSTATE: `HY000' (`ER_VARIABLE_IS_NOT_STRUCT')

     Message: Variable '%s' is not a variable component (can't be used
     as XXXX.variable_name)

   *  Error: `1273' SQLSTATE: `HY000' (`ER_UNKNOWN_COLLATION')

     Message: Unknown collation: '%s'

   *  Error: `1274' SQLSTATE: `HY000' (`ER_SLAVE_IGNORED_SSL_PARAMS')

     Message: SSL parameters in CHANGE MASTER are ignored because this
     MySQL slave was compiled without SSL support; they can be used
     later if MySQL slave with SSL is started

   *  Error: `1275' SQLSTATE: `HY000'
     (`ER_SERVER_IS_IN_SECURE_AUTH_MODE')

     Message: Server is running in -secure-auth mode, but '%s'@'%s' has
     a password in the old format; please change the password to the
     new format

   *  Error: `1276' SQLSTATE: `HY000' (`ER_WARN_FIELD_RESOLVED')

     Message: Field or reference '%s%s%s%s%s' of SELECT #%d was
     resolved in SELECT #%d

   *  Error: `1277' SQLSTATE: `HY000' (`ER_BAD_SLAVE_UNTIL_COND')

     Message: Incorrect parameter or combination of parameters for
     START SLAVE UNTIL

   *  Error: `1278' SQLSTATE: `HY000' (`ER_MISSING_SKIP_SLAVE')

     Message: It is recommended to use -skip-slave-start when doing
     step-by-step replication with START SLAVE UNTIL; otherwise, you
     will get problems if you get an unexpected slave's mysqld restart

   *  Error: `1279' SQLSTATE: `HY000' (`ER_UNTIL_COND_IGNORED')

     Message: SQL thread is not to be started so UNTIL options are
     ignored

   *  Error: `1280' SQLSTATE: `42000' (`ER_WRONG_NAME_FOR_INDEX')

     Message: Incorrect index name '%s'

   *  Error: `1281' SQLSTATE: `42000' (`ER_WRONG_NAME_FOR_CATALOG')

     Message: Incorrect catalog name '%s'

   *  Error: `1282' SQLSTATE: `HY000' (`ER_WARN_QC_RESIZE')

     Message: Query cache failed to set size %lu; new query cache size
     is %lu

   *  Error: `1283' SQLSTATE: `HY000' (`ER_BAD_FT_COLUMN')

     Message: Column '%s' cannot be part of FULLTEXT index

   *  Error: `1284' SQLSTATE: `HY000' (`ER_UNKNOWN_KEY_CACHE')

     Message: Unknown key cache '%s'

   *  Error: `1285' SQLSTATE: `HY000' (`ER_WARN_HOSTNAME_WONT_WORK')

     Message: MySQL is started in -skip-name-resolve mode; you must
     restart it without this switch for this grant to work

   *  Error: `1286' SQLSTATE: `42000' (`ER_UNKNOWN_STORAGE_ENGINE')

     Message: Unknown table engine '%s'

   *  Error: `1287' SQLSTATE: `HY000' (`ER_WARN_DEPRECATED_SYNTAX')

     Message: '%s' is deprecated; use '%s' instead

   *  Error: `1288' SQLSTATE: `HY000' (`ER_NON_UPDATABLE_TABLE')

     Message: The target table %s of the %s is not updatable

   *  Error: `1289' SQLSTATE: `HY000' (`ER_FEATURE_DISABLED')

     Message: The '%s' feature is disabled; you need MySQL built with
     '%s' to have it working

   *  Error: `1290' SQLSTATE: `HY000' (`ER_OPTION_PREVENTS_STATEMENT')

     Message: The MySQL server is running with the %s option so it
     cannot execute this statement

   *  Error: `1291' SQLSTATE: `HY000' (`ER_DUPLICATED_VALUE_IN_TYPE')

     Message: Column '%s' has duplicated value '%s' in %s

   *  Error: `1292' SQLSTATE: `22007' (`ER_TRUNCATED_WRONG_VALUE')

     Message: Truncated incorrect %s value: '%s'

   *  Error: `1293' SQLSTATE: `HY000'
     (`ER_TOO_MUCH_AUTO_TIMESTAMP_COLS')

     Message: Incorrect table definition; there can be only one
     TIMESTAMP column with CURRENT_TIMESTAMP in DEFAULT or ON UPDATE
     clause

   *  Error: `1294' SQLSTATE: `HY000' (`ER_INVALID_ON_UPDATE')

     Message: Invalid ON UPDATE clause for '%s' column

   *  Error: `1295' SQLSTATE: `HY000' (`ER_UNSUPPORTED_PS')

     Message: This command is not supported in the prepared statement
     protocol yet

   *  Error: `1296' SQLSTATE: `HY000' (`ER_GET_ERRMSG')

     Message: Got error %d '%s' from %s

   *  Error: `1297' SQLSTATE: `HY000' (`ER_GET_TEMPORARY_ERRMSG')

     Message: Got temporary error %d '%s' from %s

   *  Error: `1298' SQLSTATE: `HY000' (`ER_UNKNOWN_TIME_ZONE')

     Message: Unknown or incorrect time zone: '%s'

   *  Error: `1299' SQLSTATE: `HY000' (`ER_WARN_INVALID_TIMESTAMP')

     Message: Invalid TIMESTAMP value in column '%s' at row %ld

   *  Error: `1300' SQLSTATE: `HY000' (`ER_INVALID_CHARACTER_STRING')

     Message: Invalid %s character string: '%s'

   *  Error: `1301' SQLSTATE: `HY000'
     (`ER_WARN_ALLOWED_PACKET_OVERFLOWED')

     Message: Result of %s() was larger than max_allowed_packet (%ld) -
     truncated

   *  Error: `1302' SQLSTATE: `HY000' (`ER_CONFLICTING_DECLARATIONS')

     Message: Conflicting declarations: '%s%s' and '%s%s'

   *  Error: `1303' SQLSTATE: `2F003' (`ER_SP_NO_RECURSIVE_CREATE')

     Message: Can't create a %s from within another stored routine

   *  Error: `1304' SQLSTATE: `42000' (`ER_SP_ALREADY_EXISTS')

     Message: %s %s already exists

   *  Error: `1305' SQLSTATE: `42000' (`ER_SP_DOES_NOT_EXIST')

     Message: %s %s does not exist

   *  Error: `1306' SQLSTATE: `HY000' (`ER_SP_DROP_FAILED')

     Message: Failed to DROP %s %s

   *  Error: `1307' SQLSTATE: `HY000' (`ER_SP_STORE_FAILED')

     Message: Failed to CREATE %s %s

   *  Error: `1308' SQLSTATE: `42000' (`ER_SP_LILABEL_MISMATCH')

     Message: %s with no matching label: %s

   *  Error: `1309' SQLSTATE: `42000' (`ER_SP_LABEL_REDEFINE')

     Message: Redefining label %s

   *  Error: `1310' SQLSTATE: `42000' (`ER_SP_LABEL_MISMATCH')

     Message: End-label %s without match

   *  Error: `1311' SQLSTATE: `01000' (`ER_SP_UNINIT_VAR')

     Message: Referring to uninitialized variable %s

   *  Error: `1312' SQLSTATE: `0A000' (`ER_SP_BADSELECT')

     Message: PROCEDURE %s can't return a result set in the given
     context

   *  Error: `1313' SQLSTATE: `42000' (`ER_SP_BADRETURN')

     Message: RETURN is only allowed in a FUNCTION

   *  Error: `1314' SQLSTATE: `0A000' (`ER_SP_BADSTATEMENT')

     Message: %s is not allowed in stored procedures

   *  Error: `1315' SQLSTATE: `42000'
     (`ER_UPDATE_LOG_DEPRECATED_IGNORED')

     Message: The update log is deprecated and replaced by the binary
     log; SET SQL_LOG_UPDATE has been ignored

   *  Error: `1316' SQLSTATE: `42000'
     (`ER_UPDATE_LOG_DEPRECATED_TRANSLATED')

     Message: The update log is deprecated and replaced by the binary
     log; SET SQL_LOG_UPDATE has been translated to SET SQL_LOG_BIN

   *  Error: `1317' SQLSTATE: `70100' (`ER_QUERY_INTERRUPTED')

     Message: Query execution was interrupted

   *  Error: `1318' SQLSTATE: `42000' (`ER_SP_WRONG_NO_OF_ARGS')

     Message: Incorrect number of arguments for %s %s; expected %u, got
     %u

   *  Error: `1319' SQLSTATE: `42000' (`ER_SP_COND_MISMATCH')

     Message: Undefined CONDITION: %s

   *  Error: `1320' SQLSTATE: `42000' (`ER_SP_NORETURN')

     Message: No RETURN found in FUNCTION %s

   *  Error: `1321' SQLSTATE: `2F005' (`ER_SP_NORETURNEND')

     Message: FUNCTION %s ended without RETURN

   *  Error: `1322' SQLSTATE: `42000' (`ER_SP_BAD_CURSOR_QUERY')

     Message: Cursor statement must be a SELECT

   *  Error: `1323' SQLSTATE: `42000' (`ER_SP_BAD_CURSOR_SELECT')

     Message: Cursor SELECT must not have INTO

   *  Error: `1324' SQLSTATE: `42000' (`ER_SP_CURSOR_MISMATCH')

     Message: Undefined CURSOR: %s

   *  Error: `1325' SQLSTATE: `24000' (`ER_SP_CURSOR_ALREADY_OPEN')

     Message: Cursor is already open

   *  Error: `1326' SQLSTATE: `24000' (`ER_SP_CURSOR_NOT_OPEN')

     Message: Cursor is not open

   *  Error: `1327' SQLSTATE: `42000' (`ER_SP_UNDECLARED_VAR')

     Message: Undeclared variable: %s

   *  Error: `1328' SQLSTATE: `HY000' (`ER_SP_WRONG_NO_OF_FETCH_ARGS')

     Message: Incorrect number of FETCH variables

   *  Error: `1329' SQLSTATE: `02000' (`ER_SP_FETCH_NO_DATA')

     Message: No data - zero rows fetched, selected, or processed

   *  Error: `1330' SQLSTATE: `42000' (`ER_SP_DUP_PARAM')

     Message: Duplicate parameter: %s

   *  Error: `1331' SQLSTATE: `42000' (`ER_SP_DUP_VAR')

     Message: Duplicate variable: %s

   *  Error: `1332' SQLSTATE: `42000' (`ER_SP_DUP_COND')

     Message: Duplicate condition: %s

   *  Error: `1333' SQLSTATE: `42000' (`ER_SP_DUP_CURS')

     Message: Duplicate cursor: %s

   *  Error: `1334' SQLSTATE: `HY000' (`ER_SP_CANT_ALTER')

     Message: Failed to ALTER %s %s

   *  Error: `1335' SQLSTATE: `0A000' (`ER_SP_SUBSELECT_NYI')

     Message: Subselect value not supported

   *  Error: `1336' SQLSTATE: `0A000'
     (`ER_STMT_NOT_ALLOWED_IN_SF_OR_TRG')

     Message: %s is not allowed in stored function or trigger

   *  Error: `1337' SQLSTATE: `42000' (`ER_SP_VARCOND_AFTER_CURSHNDLR')

     Message: Variable or condition declaration after cursor or handler
     declaration

   *  Error: `1338' SQLSTATE: `42000' (`ER_SP_CURSOR_AFTER_HANDLER')

     Message: Cursor declaration after handler declaration

   *  Error: `1339' SQLSTATE: `20000' (`ER_SP_CASE_NOT_FOUND')

     Message: Case not found for CASE statement

   *  Error: `1340' SQLSTATE: `HY000' (`ER_FPARSER_TOO_BIG_FILE')

     Message: Configuration file '%s' is too big

   *  Error: `1341' SQLSTATE: `HY000' (`ER_FPARSER_BAD_HEADER')

     Message: Malformed file type header in file '%s'

   *  Error: `1342' SQLSTATE: `HY000' (`ER_FPARSER_EOF_IN_COMMENT')

     Message: Unexpected end of file while parsing comment '%s'

   *  Error: `1343' SQLSTATE: `HY000' (`ER_FPARSER_ERROR_IN_PARAMETER')

     Message: Error while parsing parameter '%s' (line: '%s')

   *  Error: `1344' SQLSTATE: `HY000'
     (`ER_FPARSER_EOF_IN_UNKNOWN_PARAMETER')

     Message: Unexpected end of file while skipping unknown parameter
     '%s'

   *  Error: `1345' SQLSTATE: `HY000' (`ER_VIEW_NO_EXPLAIN')

     Message: EXPLAIN/SHOW can not be issued; lacking privileges for
     underlying table

   *  Error: `1346' SQLSTATE: `HY000' (`ER_FRM_UNKNOWN_TYPE')

     Message: File '%s' has unknown type '%s' in its header

   *  Error: `1347' SQLSTATE: `HY000' (`ER_WRONG_OBJECT')

     Message: '%s.%s' is not %s

   *  Error: `1348' SQLSTATE: `HY000' (`ER_NONUPDATEABLE_COLUMN')

     Message: Column '%s' is not updatable

   *  Error: `1349' SQLSTATE: `HY000' (`ER_VIEW_SELECT_DERIVED')

     Message: View's SELECT contains a subquery in the FROM clause

   *  Error: `1350' SQLSTATE: `HY000' (`ER_VIEW_SELECT_CLAUSE')

     Message: View's SELECT contains a '%s' clause

   *  Error: `1351' SQLSTATE: `HY000' (`ER_VIEW_SELECT_VARIABLE')

     Message: View's SELECT contains a variable or parameter

   *  Error: `1352' SQLSTATE: `HY000' (`ER_VIEW_SELECT_TMPTABLE')

     Message: View's SELECT refers to a temporary table '%s'

   *  Error: `1353' SQLSTATE: `HY000' (`ER_VIEW_WRONG_LIST')

     Message: View's SELECT and view's field list have different column
     counts

   *  Error: `1354' SQLSTATE: `HY000' (`ER_WARN_VIEW_MERGE')

     Message: View merge algorithm can't be used here for now (assumed
     undefined algorithm)

   *  Error: `1355' SQLSTATE: `HY000' (`ER_WARN_VIEW_WITHOUT_KEY')

     Message: View being updated does not have complete key of
     underlying table in it

   *  Error: `1356' SQLSTATE: `HY000' (`ER_VIEW_INVALID')

     Message: View '%s.%s' references invalid table(s) or column(s) or
     function(s) or definer/invoker of view lack rights to use them

   *  Error: `1357' SQLSTATE: `HY000' (`ER_SP_NO_DROP_SP')

     Message: Can't drop or alter a %s from within another stored
     routine

   *  Error: `1358' SQLSTATE: `HY000' (`ER_SP_GOTO_IN_HNDLR')

     Message: GOTO is not allowed in a stored procedure handler

   *  Error: `1359' SQLSTATE: `HY000' (`ER_TRG_ALREADY_EXISTS')

     Message: Trigger already exists

   *  Error: `1360' SQLSTATE: `HY000' (`ER_TRG_DOES_NOT_EXIST')

     Message: Trigger does not exist

   *  Error: `1361' SQLSTATE: `HY000' (`ER_TRG_ON_VIEW_OR_TEMP_TABLE')

     Message: Trigger's '%s' is view or temporary table

   *  Error: `1362' SQLSTATE: `HY000' (`ER_TRG_CANT_CHANGE_ROW')

     Message: Updating of %s row is not allowed in %strigger

   *  Error: `1363' SQLSTATE: `HY000' (`ER_TRG_NO_SUCH_ROW_IN_TRG')

     Message: There is no %s row in %s trigger

   *  Error: `1364' SQLSTATE: `HY000' (`ER_NO_DEFAULT_FOR_FIELD')

     Message: Field '%s' doesn't have a default value

   *  Error: `1365' SQLSTATE: `22012' (`ER_DIVISION_BY_ZERO')

     Message: Division by 0

   *  Error: `1366' SQLSTATE: `HY000'
     (`ER_TRUNCATED_WRONG_VALUE_FOR_FIELD')

     Message: Incorrect %s value: '%s' for column '%s' at row %ld

   *  Error: `1367' SQLSTATE: `22007' (`ER_ILLEGAL_VALUE_FOR_TYPE')

     Message: Illegal %s '%s' value found during parsing

   *  Error: `1368' SQLSTATE: `HY000' (`ER_VIEW_NONUPD_CHECK')

     Message: CHECK OPTION on non-updatable view '%s.%s'

   *  Error: `1369' SQLSTATE: `HY000' (`ER_VIEW_CHECK_FAILED')

     Message: CHECK OPTION failed '%s.%s'

   *  Error: `1370' SQLSTATE: `42000' (`ER_PROCACCESS_DENIED_ERROR')

     Message: %s command denied to user '%s'@'%s' for routine '%s'

   *  Error: `1371' SQLSTATE: `HY000' (`ER_RELAY_LOG_FAIL')

     Message: Failed purging old relay logs: %s

   *  Error: `1372' SQLSTATE: `HY000' (`ER_PASSWD_LENGTH')

     Message: Password hash should be a %d-digit hexadecimal number

   *  Error: `1373' SQLSTATE: `HY000' (`ER_UNKNOWN_TARGET_BINLOG')

     Message: Target log not found in binlog index

   *  Error: `1374' SQLSTATE: `HY000' (`ER_IO_ERR_LOG_INDEX_READ')

     Message: I/O error reading log index file

   *  Error: `1375' SQLSTATE: `HY000' (`ER_BINLOG_PURGE_PROHIBITED')

     Message: Server configuration does not permit binlog purge

   *  Error: `1376' SQLSTATE: `HY000' (`ER_FSEEK_FAIL')

     Message: Failed on fseek()

   *  Error: `1377' SQLSTATE: `HY000' (`ER_BINLOG_PURGE_FATAL_ERR')

     Message: Fatal error during log purge

   *  Error: `1378' SQLSTATE: `HY000' (`ER_LOG_IN_USE')

     Message: A purgeable log is in use, will not purge

   *  Error: `1379' SQLSTATE: `HY000' (`ER_LOG_PURGE_UNKNOWN_ERR')

     Message: Unknown error during log purge

   *  Error: `1380' SQLSTATE: `HY000' (`ER_RELAY_LOG_INIT')

     Message: Failed initializing relay log position: %s

   *  Error: `1381' SQLSTATE: `HY000' (`ER_NO_BINARY_LOGGING')

     Message: You are not using binary logging

   *  Error: `1382' SQLSTATE: `HY000' (`ER_RESERVED_SYNTAX')

     Message: The '%s' syntax is reserved for purposes internal to the
     MySQL server

   *  Error: `1383' SQLSTATE: `HY000' (`ER_WSAS_FAILED')

     Message: WSAStartup Failed

   *  Error: `1384' SQLSTATE: `HY000' (`ER_DIFF_GROUPS_PROC')

     Message: Can't handle procedures with different groups yet

   *  Error: `1385' SQLSTATE: `HY000' (`ER_NO_GROUP_FOR_PROC')

     Message: Select must have a group with this procedure

   *  Error: `1386' SQLSTATE: `HY000' (`ER_ORDER_WITH_PROC')

     Message: Can't use ORDER clause with this procedure

   *  Error: `1387' SQLSTATE: `HY000'
     (`ER_LOGGING_PROHIBIT_CHANGING_OF')

     Message: Binary logging and replication forbid changing the global
     server %s

   *  Error: `1388' SQLSTATE: `HY000' (`ER_NO_FILE_MAPPING')

     Message: Can't map file: %s, errno: %d

   *  Error: `1389' SQLSTATE: `HY000' (`ER_WRONG_MAGIC')

     Message: Wrong magic in %s

   *  Error: `1390' SQLSTATE: `HY000' (`ER_PS_MANY_PARAM')

     Message: Prepared statement contains too many placeholders

   *  Error: `1391' SQLSTATE: `HY000' (`ER_KEY_PART_0')

     Message: Key part '%s' length cannot be 0

   *  Error: `1392' SQLSTATE: `HY000' (`ER_VIEW_CHECKSUM')

     Message: View text checksum failed

   *  Error: `1393' SQLSTATE: `HY000' (`ER_VIEW_MULTIUPDATE')

     Message: Can not modify more than one base table through a join
     view '%s.%s'

   *  Error: `1394' SQLSTATE: `HY000' (`ER_VIEW_NO_INSERT_FIELD_LIST')

     Message: Can not insert into join view '%s.%s' without fields list

   *  Error: `1395' SQLSTATE: `HY000' (`ER_VIEW_DELETE_MERGE_VIEW')

     Message: Can not delete from join view '%s.%s'

   *  Error: `1396' SQLSTATE: `HY000' (`ER_CANNOT_USER')

     Message: Operation %s failed for %s

   *  Error: `1397' SQLSTATE: `XAE04' (`ER_XAER_NOTA')

     Message: XAER_NOTA: Unknown XID

   *  Error: `1398' SQLSTATE: `XAE05' (`ER_XAER_INVAL')

     Message: XAER_INVAL: Invalid arguments (or unsupported command)

   *  Error: `1399' SQLSTATE: `XAE07' (`ER_XAER_RMFAIL')

     Message: XAER_RMFAIL: The command cannot be executed when global
     transaction is in the %s state

   *  Error: `1400' SQLSTATE: `XAE09' (`ER_XAER_OUTSIDE')

     Message: XAER_OUTSIDE: Some work is done outside global transaction

   *  Error: `1401' SQLSTATE: `XAE03' (`ER_XAER_RMERR')

     Message: XAER_RMERR: Fatal error occurred in the transaction
     branch - check your data for consistency

   *  Error: `1402' SQLSTATE: `XA100' (`ER_XA_RBROLLBACK')

     Message: XA_RBROLLBACK: Transaction branch was rolled back

   *  Error: `1403' SQLSTATE: `42000' (`ER_NONEXISTING_PROC_GRANT')

     Message: There is no such grant defined for user '%s' on host '%s'
     on routine '%s'

   *  Error: `1404' SQLSTATE: `HY000' (`ER_PROC_AUTO_GRANT_FAIL')

     Message: Failed to grant EXECUTE and ALTER ROUTINE privileges

   *  Error: `1405' SQLSTATE: `HY000' (`ER_PROC_AUTO_REVOKE_FAIL')

     Message: Failed to revoke all privileges to dropped routine

   *  Error: `1406' SQLSTATE: `22001' (`ER_DATA_TOO_LONG')

     Message: Data too long for column '%s' at row %ld

   *  Error: `1407' SQLSTATE: `42000' (`ER_SP_BAD_SQLSTATE')

     Message: Bad SQLSTATE: '%s'

   *  Error: `1408' SQLSTATE: `HY000' (`ER_STARTUP')

     Message: %s: ready for connections. Version: '%s' socket: '%s'
     port: %d %s

   *  Error: `1409' SQLSTATE: `HY000'
     (`ER_LOAD_FROM_FIXED_SIZE_ROWS_TO_VAR')

     Message: Can't load value from file with fixed size rows to
     variable

   *  Error: `1410' SQLSTATE: `42000' (`ER_CANT_CREATE_USER_WITH_GRANT')

     Message: You are not allowed to create a user with GRANT

   *  Error: `1411' SQLSTATE: `HY000' (`ER_WRONG_VALUE_FOR_TYPE')

     Message: Incorrect %s value: '%s' for function %s

   *  Error: `1412' SQLSTATE: `HY000' (`ER_TABLE_DEF_CHANGED')

     Message: Table definition has changed, please retry transaction

   *  Error: `1413' SQLSTATE: `42000' (`ER_SP_DUP_HANDLER')

     Message: Duplicate handler declared in the same block

   *  Error: `1414' SQLSTATE: `42000' (`ER_SP_NOT_VAR_ARG')

     Message: OUT or INOUT argument %d for routine %s is not a variable
     or NEW pseudo-variable in BEFORE trigger

   *  Error: `1415' SQLSTATE: `0A000' (`ER_SP_NO_RETSET')

     Message: Not allowed to return a result set from a %s

   *  Error: `1416' SQLSTATE: `22003' (`ER_CANT_CREATE_GEOMETRY_OBJECT')

     Message: Cannot get geometry object from data you send to the
     GEOMETRY field

   *  Error: `1417' SQLSTATE: `HY000' (`ER_FAILED_ROUTINE_BREAK_BINLOG')

     Message: A routine failed and has neither NO SQL nor READS SQL
     DATA in its declaration and binary logging is enabled; if
     non-transactional tables were updated, the binary log will miss
     their changes

   *  Error: `1418' SQLSTATE: `HY000' (`ER_BINLOG_UNSAFE_ROUTINE')

     Message: This function has none of DETERMINISTIC, NO SQL, or READS
     SQL DATA in its declaration and binary logging is enabled (you
     *might* want to use the less safe log_bin_trust_function_creators
     variable)

   *  Error: `1419' SQLSTATE: `HY000'
     (`ER_BINLOG_CREATE_ROUTINE_NEED_SUPER')

     Message: You do not have the SUPER privilege and binary logging is
     enabled (you *might* want to use the less safe
     log_bin_trust_function_creators variable)

   *  Error: `1420' SQLSTATE: `HY000' (`ER_EXEC_STMT_WITH_OPEN_CURSOR')

     Message: You can't execute a prepared statement which has an open
     cursor associated with it. Reset the statement to re-execute it.

   *  Error: `1421' SQLSTATE: `HY000' (`ER_STMT_HAS_NO_OPEN_CURSOR')

     Message: The statement (%lu) has no open cursor.

   *  Error: `1422' SQLSTATE: `HY000'
     (`ER_COMMIT_NOT_ALLOWED_IN_SF_OR_TRG')

     Message: Explicit or implicit commit is not allowed in stored
     function or trigger.

   *  Error: `1423' SQLSTATE: `HY000' (`ER_NO_DEFAULT_FOR_VIEW_FIELD')

     Message: Field of view '%s.%s' underlying table doesn't have a
     default value

   *  Error: `1424' SQLSTATE: `HY000' (`ER_SP_NO_RECURSION')

     Message: Recursive stored functions and triggers are not allowed.

   *  Error: `1425' SQLSTATE: `42000' (`ER_TOO_BIG_SCALE')

     Message: Too big scale %lu specified for column '%s'. Maximum is
     %d.

   *  Error: `1426' SQLSTATE: `42000' (`ER_TOO_BIG_PRECISION')

     Message: Too big precision %lu specified for column '%s'. Maximum
     is %lu.

   *  Error: `1427' SQLSTATE: `42000' (`ER_M_BIGGER_THAN_D')

     Message: For float(M,D), double(M,D) or decimal(M,D), M must be >=
     D (column '%s').

   *  Error: `1428' SQLSTATE: `HY000' (`ER_WRONG_LOCK_OF_SYSTEM_TABLE')

     Message: You can't combine write-locking of system '%s.%s' table
     with other tables

   *  Error: `1429' SQLSTATE: `HY000'
     (`ER_CONNECT_TO_FOREIGN_DATA_SOURCE')

     Message: Unable to connect to foreign data source: %s

   *  Error: `1430' SQLSTATE: `HY000'
     (`ER_QUERY_ON_FOREIGN_DATA_SOURCE')

     Message: There was a problem processing the query on the foreign
     data source. Data source error: %s

   *  Error: `1431' SQLSTATE: `HY000'
     (`ER_FOREIGN_DATA_SOURCE_DOESNT_EXIST')

     Message: The foreign data source you are trying to reference does
     not exist. Data source error: %s

   *  Error: `1432' SQLSTATE: `HY000'
     (`ER_FOREIGN_DATA_STRING_INVALID_CANT_CREATE')

     Message: Can't create federated table. The data source connection
     string '%s' is not in the correct format

   *  Error: `1433' SQLSTATE: `HY000' (`ER_FOREIGN_DATA_STRING_INVALID')

     Message: The data source connection string '%s' is not in the
     correct format

   *  Error: `1434' SQLSTATE: `HY000' (`ER_CANT_CREATE_FEDERATED_TABLE')

     Message: Can't create federated table. Foreign data src error: %s

   *  Error: `1435' SQLSTATE: `HY000' (`ER_TRG_IN_WRONG_SCHEMA')

     Message: Trigger in wrong schema

   *  Error: `1436' SQLSTATE: `HY000' (`ER_STACK_OVERRUN_NEED_MORE')

     Message: Thread stack overrun: %ld bytes used of a %ld byte stack,
     and %ld bytes needed. Use 'mysqld -O thread_stack=#' to specify a
     bigger stack.

   *  Error: `1437' SQLSTATE: `42000' (`ER_TOO_LONG_BODY')

     Message: Routine body for '%s' is too long

   *  Error: `1438' SQLSTATE: `HY000'
     (`ER_WARN_CANT_DROP_DEFAULT_KEYCACHE')

     Message: Cannot drop default keycache

   *  Error: `1439' SQLSTATE: `42000' (`ER_TOO_BIG_DISPLAYWIDTH')

     Message: Display width out of range for column '%s' (max = %lu)

   *  Error: `1440' SQLSTATE: `XAE08' (`ER_XAER_DUPID')

     Message: XAER_DUPID: The XID already exists

   *  Error: `1441' SQLSTATE: `22008' (`ER_DATETIME_FUNCTION_OVERFLOW')

     Message: Datetime function: %s field overflow

   *  Error: `1442' SQLSTATE: `HY000'
     (`ER_CANT_UPDATE_USED_TABLE_IN_SF_OR_TRG')

     Message: Can't update table '%s' in stored function/trigger
     because it is already used by statement which invoked this stored
     function/trigger.

   *  Error: `1443' SQLSTATE: `HY000' (`ER_VIEW_PREVENT_UPDATE')

     Message: The definition of table '%s' prevents operation %s on
     table '%s'.

   *  Error: `1444' SQLSTATE: `HY000' (`ER_PS_NO_RECURSION')

     Message: The prepared statement contains a stored routine call
     that refers to that same statement. It's not allowed to execute a
     prepared statement in such a recursive manner

   *  Error: `1445' SQLSTATE: `HY000' (`ER_SP_CANT_SET_AUTOCOMMIT')

     Message: Not allowed to set autocommit from a stored function or
     trigger

   *  Error: `1446' SQLSTATE: `HY000' (`ER_MALFORMED_DEFINER')

     Message: Definer is not fully qualified

   *  Error: `1447' SQLSTATE: `HY000' (`ER_VIEW_FRM_NO_USER')

     Message: View '%s'.'%s' has no definer information (old table
     format). Current user is used as definer. Please recreate the view!

   *  Error: `1448' SQLSTATE: `HY000' (`ER_VIEW_OTHER_USER')

     Message: You need the SUPER privilege for creation view with
     '%s'@'%s' definer

   *  Error: `1449' SQLSTATE: `HY000' (`ER_NO_SUCH_USER')

     Message: There is no '%s'@'%s' registered

   *  Error: `1450' SQLSTATE: `HY000' (`ER_FORBID_SCHEMA_CHANGE')

     Message: Changing schema from '%s' to '%s' is not allowed.

   *  Error: `1451' SQLSTATE: `23000' (`ER_ROW_IS_REFERENCED_2')

     Message: Cannot delete or update a parent row: a foreign key
     constraint fails (%s)

   *  Error: `1452' SQLSTATE: `23000' (`ER_NO_REFERENCED_ROW_2')

     Message: Cannot add or update a child row: a foreign key
     constraint fails (%s)

   *  Error: `1453' SQLSTATE: `42000' (`ER_SP_BAD_VAR_SHADOW')

     Message: Variable '%s' must be quoted with `...`, or renamed

   *  Error: `1454' SQLSTATE: `HY000' (`ER_TRG_NO_DEFINER')

     Message: No definer attribute for trigger '%s'.'%s'. The trigger
     will be activated under the authorization of the invoker, which
     may have insufficient privileges. Please recreate the trigger.

   *  Error: `1455' SQLSTATE: `HY000' (`ER_OLD_FILE_FORMAT')

     Message: '%s' has an old format, you should re-create the '%s'
     object(s)

   *  Error: `1456' SQLSTATE: `HY000' (`ER_SP_RECURSION_LIMIT')

     Message: Recursive limit %d (as set by the max_sp_recursion_depth
     variable) was exceeded for routine %s

   *  Error: `1457' SQLSTATE: `HY000' (`ER_SP_PROC_TABLE_CORRUPT')

     Message: Failed to load routine %s. The table mysql.proc is
     missing, corrupt, or contains bad data (internal code %d)

   *  Error: `1458' SQLSTATE: `42000' (`ER_SP_WRONG_NAME')

     Message: Incorrect routine name '%s'

   *  Error: `1459' SQLSTATE: `HY000' (`ER_TABLE_NEEDS_UPGRADE')

     Message: Table upgrade required. Please do "REPAIR TABLE `%s`" to
     fix it!

   *  Error: `1460' SQLSTATE: `42000' (`ER_SP_NO_AGGREGATE')

     Message: AGGREGATE is not supported for stored functions

   *  Error: `1461' SQLSTATE: `42000'
     (`ER_MAX_PREPARED_STMT_COUNT_REACHED')

     Message: Can't create more than max_prepared_stmt_count statements
     (current value: %lu)

   *  Error: `1462' SQLSTATE: `HY000' (`ER_VIEW_RECURSIVE')

     Message: `%s`.`%s` contains view recursion

   *  Error: `1463' SQLSTATE: `42000' (`ER_NON_GROUPING_FIELD_USED')

     Message: non-grouping field '%s' is used in %s clause

   *  Error: `1464' SQLSTATE: `HY000' (`ER_TABLE_CANT_HANDLE_SPKEYS')

     Message: The used table type doesn't support SPATIAL indexes

   *  Error: `1465' SQLSTATE: `HY000'
     (`ER_NO_TRIGGERS_ON_SYSTEM_SCHEMA')

     Message: Triggers can not be created on system tables

   *  Error: `1466' SQLSTATE: `HY000' (`ER_REMOVED_SPACES')

     Message: Leading spaces are removed from name '%s'

   *  Error: `1467' SQLSTATE: `HY000' (`ER_AUTOINC_READ_FAILED')

     Message: Failed to read auto-increment value from storage engine

   *  Error: `1468' SQLSTATE: `HY000' (`ER_USERNAME')

     Message: user name

   *  Error: `1469' SQLSTATE: `HY000' (`ER_HOSTNAME')

     Message: host name

   *  Error: `1470' SQLSTATE: `HY000' (`ER_WRONG_STRING_LENGTH')

     Message: String '%s' is too long for %s (should be no longer than
     %d)

   *  Error: `1471' SQLSTATE: `HY000' (`ER_NON_INSERTABLE_TABLE')

     Message: The target table %s of the %s is not insertable-into

   *  Error: `1472' SQLSTATE: `HY000' (`ER_ADMIN_WRONG_MRG_TABLE')

     Message: Table '%s' is differently defined or of non-MyISAM type
     or doesn't exist

   *  Error: `1473' SQLSTATE: `HY000'
     (`ER_TOO_HIGH_LEVEL_OF_NESTING_FOR_SELECT')

     Message: Too high level of nesting for select

   *  Error: `1474' SQLSTATE: `HY000' (`ER_NAME_BECOMES_EMPTY')

     Message: Name '%s' has become "

   *  Error: `1475' SQLSTATE: `HY000' (`ER_AMBIGUOUS_FIELD_TERM')

     Message: First character of the FIELDS TERMINATED string is
     ambiguous; please use non-optional and non-empty FIELDS ENCLOSED BY

   *  Error: `1476' SQLSTATE: `HY000' (`ER_LOAD_DATA_INVALID_COLUMN')

     Message: Invalid column reference (%s) in LOAD DATA

   *  Error: `1477' SQLSTATE: `HY000' (`ER_LOG_PURGE_NO_FILE')

     Message: Being purged log %s was not found

   *  Error: `1478' SQLSTATE: `XA106' (`ER_XA_RBTIMEOUT')

     Message: XA_RBTIMEOUT: Transaction branch was rolled back: took
     too long

   *  Error: `1479' SQLSTATE: `XA102' (`ER_XA_RBDEADLOCK')

     Message: XA_RBDEADLOCK: Transaction branch was rolled back:
     deadlock was detected

   *  Error: `1480' SQLSTATE: `HY000' (`ER_TOO_MANY_CONCURRENT_TRXS')

     Message: Too many active concurrent transactions


File: manual.info,  Node: error-messages-client,  Next: problems,  Prev: error-messages-server,  Up: error-handling

C.4 Client Error Codes and Messages
===================================

Client error information comes from the following source files:

   * The Error values and the symbols in parentheses correspond to
     definitions in the `include/errmsg.h' MySQL source file.

   * The Message values correspond to the error messages that are
     listed in the `libmysql/errmsg.c' file.  `%d' and `%s' represent
     numbers and strings, respectively, that are substituted into the
     messages when they are displayed.

Because updates are frequent, it is possible that those files will
contain additional error information not listed here.

   *  Error: `2000' (`CR_UNKNOWN_ERROR')

     Message: Unknown MySQL error

   *  Error: `2001' (`CR_SOCKET_CREATE_ERROR')

     Message: Can't create UNIX socket (%d)

   *  Error: `2002' (`CR_CONNECTION_ERROR')

     Message: Can't connect to local MySQL server through socket '%s'
     (%d)

   *  Error: `2003' (`CR_CONN_HOST_ERROR')

     Message: Can't connect to MySQL server on '%s' (%d)

   *  Error: `2004' (`CR_IPSOCK_ERROR')

     Message: Can't create TCP/IP socket (%d)

   *  Error: `2005' (`CR_UNKNOWN_HOST')

     Message: Unknown MySQL server host '%s' (%d)

   *  Error: `2006' (`CR_SERVER_GONE_ERROR')

     Message: MySQL server has gone away

   *  Error: `2007' (`CR_VERSION_ERROR')

     Message: Protocol mismatch; server version = %d, client version =
     %d

   *  Error: `2008' (`CR_OUT_OF_MEMORY')

     Message: MySQL client ran out of memory

   *  Error: `2009' (`CR_WRONG_HOST_INFO')

     Message: Wrong host info

   *  Error: `2010' (`CR_LOCALHOST_CONNECTION')

     Message: Localhost via UNIX socket

   *  Error: `2011' (`CR_TCP_CONNECTION')

     Message: %s via TCP/IP

   *  Error: `2012' (`CR_SERVER_HANDSHAKE_ERR')

     Message: Error in server handshake

   *  Error: `2013' (`CR_SERVER_LOST')

     Message: Lost connection to MySQL server during query

   *  Error: `2014' (`CR_COMMANDS_OUT_OF_SYNC')

     Message: Commands out of sync; you can't run this command now

   *  Error: `2015' (`CR_NAMEDPIPE_CONNECTION')

     Message: Named pipe: %s

   *  Error: `2016' (`CR_NAMEDPIPEWAIT_ERROR')

     Message: Can't wait for named pipe to host: %s pipe: %s (%lu)

   *  Error: `2017' (`CR_NAMEDPIPEOPEN_ERROR')

     Message: Can't open named pipe to host: %s pipe: %s (%lu)

   *  Error: `2018' (`CR_NAMEDPIPESETSTATE_ERROR')

     Message: Can't set state of named pipe to host: %s pipe: %s (%lu)

   *  Error: `2019' (`CR_CANT_READ_CHARSET')

     Message: Can't initialize character set %s (path: %s)

   *  Error: `2020' (`CR_NET_PACKET_TOO_LARGE')

     Message: Got packet bigger than 'max_allowed_packet' bytes

   *  Error: `2021' (`CR_EMBEDDED_CONNECTION')

     Message: Embedded server

   *  Error: `2022' (`CR_PROBE_SLAVE_STATUS')

     Message: Error on SHOW SLAVE STATUS:

   *  Error: `2023' (`CR_PROBE_SLAVE_HOSTS')

     Message: Error on SHOW SLAVE HOSTS:

   *  Error: `2024' (`CR_PROBE_SLAVE_CONNECT')

     Message: Error connecting to slave:

   *  Error: `2025' (`CR_PROBE_MASTER_CONNECT')

     Message: Error connecting to master:

   *  Error: `2026' (`CR_SSL_CONNECTION_ERROR')

     Message: SSL connection error

   *  Error: `2027' (`CR_MALFORMED_PACKET')

     Message: Malformed packet

   *  Error: `2028' (`CR_WRONG_LICENSE')

     Message: This client library is licensed only for use with MySQL
     servers having '%s' license

   *  Error: `2029' (`CR_NULL_POINTER')

     Message: Invalid use of null pointer

   *  Error: `2030' (`CR_NO_PREPARE_STMT')

     Message: Statement not prepared

   *  Error: `2031' (`CR_PARAMS_NOT_BOUND')

     Message: No data supplied for parameters in prepared statement

   *  Error: `2032' (`CR_DATA_TRUNCATED')

     Message: Data truncated

   *  Error: `2033' (`CR_NO_PARAMETERS_EXISTS')

     Message: No parameters exist in the statement

   *  Error: `2034' (`CR_INVALID_PARAMETER_NO')

     Message: Invalid parameter number

   *  Error: `2035' (`CR_INVALID_BUFFER_USE')

     Message: Can't send long data for non-string/non-binary data types
     (parameter: %d)

   *  Error: `2036' (`CR_UNSUPPORTED_PARAM_TYPE')

     Message: Using unsupported buffer type: %d (parameter: %d)

   *  Error: `2037' (`CR_SHARED_MEMORY_CONNECTION')

     Message: Shared memory: %s

   *  Error: `2038' (`CR_SHARED_MEMORY_CONNECT_REQUEST_ERROR')

     Message: Can't open shared memory; client could not create request
     event (%lu)

   *  Error: `2039' (`CR_SHARED_MEMORY_CONNECT_ANSWER_ERROR')

     Message: Can't open shared memory; no answer event received from
     server (%lu)

   *  Error: `2040' (`CR_SHARED_MEMORY_CONNECT_FILE_MAP_ERROR')

     Message: Can't open shared memory; server could not allocate file
     mapping (%lu)

   *  Error: `2041' (`CR_SHARED_MEMORY_CONNECT_MAP_ERROR')

     Message: Can't open shared memory; server could not get pointer to
     file mapping (%lu)

   *  Error: `2042' (`CR_SHARED_MEMORY_FILE_MAP_ERROR')

     Message: Can't open shared memory; client could not allocate file
     mapping (%lu)

   *  Error: `2043' (`CR_SHARED_MEMORY_MAP_ERROR')

     Message: Can't open shared memory; client could not get pointer to
     file mapping (%lu)

   *  Error: `2044' (`CR_SHARED_MEMORY_EVENT_ERROR')

     Message: Can't open shared memory; client could not create %s
     event (%lu)

   *  Error: `2045' (`CR_SHARED_MEMORY_CONNECT_ABANDONED_ERROR')

     Message: Can't open shared memory; no answer from server (%lu)

   *  Error: `2046' (`CR_SHARED_MEMORY_CONNECT_SET_ERROR')

     Message: Can't open shared memory; cannot send request event to
     server (%lu)

   *  Error: `2047' (`CR_CONN_UNKNOW_PROTOCOL')

     Message: Wrong or unknown protocol

   *  Error: `2048' (`CR_INVALID_CONN_HANDLE')

     Message: Invalid connection handle

   *  Error: `2049' (`CR_SECURE_AUTH')

     Message: Connection using old (pre-4.1.1) authentication protocol
     refused (client option 'secure_auth' enabled)

   *  Error: `2050' (`CR_FETCH_CANCELED')

     Message: Row retrieval was canceled by mysql_stmt_close() call

   *  Error: `2051' (`CR_NO_DATA')

     Message: Attempt to read column without prior row fetch

   *  Error: `2052' (`CR_NO_STMT_METADATA')

     Message: Prepared statement contains no metadata

   *  Error: `2053' (`CR_NO_RESULT_SET')

     Message: Attempt to read a row while there is no result set
     associated with the statement

   *  Error: `2054' (`CR_NOT_IMPLEMENTED')

     Message: This feature is not implemented yet

   *  Error: `2055' (`CR_SERVER_LOST_EXTENDED')

     Message: Lost connection to MySQL server at '%s', system error: %d


File: manual.info,  Node: problems,  Prev: error-messages-client,  Up: error-handling

C.5 Problems and Common Errors
==============================

* Menu:

* what-is-crashing::             How to Determine What Is Causing a Problem
* common-errors::                Common Errors When Using MySQL Programs
* installation-issues::          Installation-Related Issues
* administration-issues::        Administration-Related Issues
* query-issues::                 Query-Related Issues
* optimizer-issues::             Optimizer-Related Issues
* table-definition-issues::      Table Definition-Related Issues
* bugs::                         Known Issues in MySQL

This section lists some common problems and error messages that you may
encounter. It describes how to determine the causes of the problems and
what to do to solve them.


File: manual.info,  Node: what-is-crashing,  Next: common-errors,  Prev: problems,  Up: problems

C.5.1 How to Determine What Is Causing a Problem
------------------------------------------------

When you run into a problem, the first thing you should do is to find
out which program or piece of equipment is causing it:

   * If you have one of the following symptoms, then it is probably a
     hardware problems (such as memory, motherboard, CPU, or hard disk)
     or kernel problem:

        * The keyboard doesn't work. This can normally be checked by
          pressing the Caps Lock key. If the Caps Lock light doesn't
          change, you have to replace your keyboard.  (Before doing
          this, you should try to restart your computer and check all
          cables to the keyboard.)

        * The mouse pointer doesn't move.

        * The machine doesn't answer to a remote machine's pings.

        * Other programs that are not related to MySQL don't behave
          correctly.

        * Your system restarted unexpectedly. (A faulty user-level
          program should never be able to take down your system.)

     In this case, you should start by checking all your cables and run
     some diagnostic tool to check your hardware! You should also check
     whether there are any patches, updates, or service packs for your
     operating system that could likely solve your problem. Check also
     that all your libraries (such as `glibc') are up to date.

     It is always good to use a machine with ECC memory to discover
     memory problems early.

   * If your keyboard is locked up, you may be able to recover by
     logging in to your machine from another machine and executing
     `kbd_mode -a'.

   * Please examine your system log file (`/var/log/messages' or
     similar) for reasons for your problem. If you think the problem is
     in MySQL, you should also examine MySQL's log files. See *Note
     server-logs::.

   * If you don't think you have hardware problems, you should try to
     find out which program is causing problems. Try using `top', `ps',
     Task Manager, or some similar program, to check which program is
     taking all CPU or is locking the machine.

   * Use `top', `df', or a similar program to check whether you are out
     of memory, disk space, file descriptors, or some other critical
     resource.

   * If the problem is some runaway process, you can always try to kill
     it. If it doesn't want to die, there is probably a bug in the
     operating system.

If after you have examined all other possibilities and you have
concluded that the MySQL server or a MySQL client is causing the
problem, it is time to create a bug report for our mailing list or our
support team. In the bug report, try to give a very detailed
description of how the system is behaving and what you think is
happening. You should also state why you think that MySQL is causing
the problem. Take into consideration all the situations in this
chapter. State any problems exactly how they appear when you examine
your system. Use the `copy and paste' method for any output and error
messages from programs and log files.

Try to describe in detail which program is not working and all symptoms
you see. We have in the past received many bug reports that state only
`the system doesn't work.' This doesn't provide us with any information
about what could be the problem.

If a program fails, it is always useful to know the following
information:

   * Has the program in question made a segmentation fault (did it dump
     core)?

   * Is the program taking up all available CPU time? Check with `top'.
     Let the program run for a while, it may simply be evaluating
     something computationally intensive.

   * If the *Note `mysqld': mysqld. server is causing problems, can you
     get any response from it with *Note `mysqladmin -u root ping':
     mysqladmin. or *Note `mysqladmin -u root processlist': mysqladmin.?

   * What does a client program say when you try to connect to the
     MySQL server? (Try with *Note `mysql': mysql, for example.) Does
     the client jam? Do you get any output from the program?

When sending a bug report, you should follow the outline described in
*Note bug-reports::.


File: manual.info,  Node: common-errors,  Next: installation-issues,  Prev: what-is-crashing,  Up: problems

C.5.2 Common Errors When Using MySQL Programs
---------------------------------------------

* Menu:

* error-access-denied::          `Access denied'
* can-not-connect-to-server::    `Can't connect to [local] MySQL server'
* error-lost-connection::        `Lost connection to MySQL server'
* old-client::                   `Client does not support authentication protocol'
* password-too-long::            Password Fails When Entered Interactively
* blocked-host::                 `Host 'HOST_NAME' is blocked'
* too-many-connections::         `Too many connections'
* out-of-memory::                `Out of memory'
* gone-away::                    `MySQL server has gone away'
* packet-too-large::             `Packet too large'
* communication-errors::         Communication Errors and Aborted Connections
* full-table::                   `The table is full'
* cannot-create::                `Can't create/write to file'
* commands-out-of-sync::         `Commands out of sync'
* ignoring-user::                `Ignoring user'
* cannot-find-table::            `Table 'TBL_NAME' doesn't exist'
* cannot-initialize-character-set::  `Can't initialize character set'
* not-enough-file-handles::      `'FILE' Not Found' and Similar Errors
* table-corruption::             Table-Corruption Issues

This section lists some errors that users frequently encounter when
running MySQL programs. Although the problems show up when you try to
run client programs, the solutions to many of the problems involves
changing the configuration of the MySQL server.


File: manual.info,  Node: error-access-denied,  Next: can-not-connect-to-server,  Prev: common-errors,  Up: common-errors

C.5.2.1 `Access denied'
.......................

An `Access denied' error can have many causes. Often the problem is
related to the MySQL accounts that the server permits client programs
to use when connecting. See *Note privilege-system::, and *Note
access-denied::.


File: manual.info,  Node: can-not-connect-to-server,  Next: error-lost-connection,  Prev: error-access-denied,  Up: common-errors

C.5.2.2 `Can't connect to [local] MySQL server'
...............................................

* Menu:

* can-not-connect-to-server-on-windows::  `Connection to MySQL Server Failing on Windows'

A MySQL client on Unix can connect to the *Note `mysqld': mysqld.
server in two different ways: By using a Unix socket file to connect
through a file in the file system (default `/tmp/mysql.sock'), or by
using TCP/IP, which connects through a port number. A Unix socket file
connection is faster than TCP/IP, but can be used only when connecting
to a server on the same computer. A Unix socket file is used if you
don't specify a host name or if you specify the special host name
`localhost'.

If the MySQL server is running on Windows, you can connect using
TCP/IP. If the server is started with the `--enable-named-pipe' option,
you can also connect with named pipes if you run the client on the host
where the server is running. The name of the named pipe is `MySQL' by
default. If you don't give a host name when connecting to *Note
`mysqld': mysqld, a MySQL client first tries to connect to the named
pipe. If that doesn't work, it connects to the TCP/IP port. You can
force the use of named pipes on Windows by using `.' as the host name.

The error (2002) `Can't connect to ...' normally means that there is no
MySQL server running on the system or that you are using an incorrect
Unix socket file name or TCP/IP port number when trying to connect to
the server. You should also check that the TCP/IP port you are using
has not been blocked by a firewall or port blocking service.

The error (2003) `Can't connect to MySQL server on 'SERVER' (10061)'
indicates that the network connection has been refused. You should
check that there is a MySQL server running, that it has network
connections enabled, and that the network port you specified is the one
configured on the server.

Start by checking whether there is a process named *Note `mysqld':
mysqld. running on your server host. (Use `ps xa | grep mysqld' on Unix
or the Task Manager on Windows.) If there is no such process, you should
start the server. See *Note starting-server::.

If a *Note `mysqld': mysqld. process is running, you can check it by
trying the following commands. The port number or Unix socket file name
might be different in your setup.  `host_ip' represents the IP address
of the machine where the server is running.

     shell> mysqladmin version
     shell> mysqladmin variables
     shell> mysqladmin -h `hostname` version variables
     shell> mysqladmin -h `hostname` --port=3306 version
     shell> mysqladmin -h host_ip version
     shell> mysqladmin --protocol=SOCKET --socket=/tmp/mysql.sock version

Note the use of backticks rather than forward quotation marks with the
`hostname' command; these cause the output of `hostname' (that is, the
current host name) to be substituted into the *Note `mysqladmin':
mysqladmin. command. If you have no `hostname' command or are running
on Windows, you can manually type the host name of your machine (without
backticks) following the `-h' option. You can also try `-h 127.0.0.1'
to connect with TCP/IP to the local host.

Make sure that the server has not been configured to ignore network
connections or (if you are attempting to connect remotely) that it has
not been configured to listen only locally on its network interfaces.
If the server was started with `--skip-networking', it will not accept
TCP/IP connections at all. If the server was started with
`--bind-address=127.0.0.1', it will listen for TCP/IP connections only
locally on the loopback interface and will not accept remote
connections.

Check to make sure that there is no firewall blocking access to MySQL.
Your firewall may be configured on the basis of the application being
executed, or the port number used by MySQL for communication (3306 by
default). Under Linux or Unix, check your IP tables (or similar)
configuration to ensure that the port has not been blocked. Under
Windows, applications such as ZoneAlarm or the Windows XP personal
firewall may need to be configured not to block the MySQL port.

Here are some reasons the `Can't connect to local MySQL server' error
might occur:

   * *Note `mysqld': mysqld. is not running on the local host. Check
     your operating system's process list to ensure the *Note `mysqld':
     mysqld. process is present.

   * You're running a MySQL server on Windows with many TCP/IP
     connections to it. If you're experiencing that quite often your
     clients get that error, you can find a workaround here: *Note
     can-not-connect-to-server-on-windows::.

   * Someone has removed the Unix socket file that *Note `mysqld':
     mysqld. uses (`/tmp/mysql.sock' by default). For example, you
     might have a `cron' job that removes old files from the `/tmp'
     directory. You can always run *Note `mysqladmin version':
     mysqladmin. to check whether the Unix socket file that *Note
     `mysqladmin': mysqladmin. is trying to use really exists. The fix
     in this case is to change the `cron' job to not remove
     `mysql.sock' or to place the socket file somewhere else. See *Note
     problems-with-mysql-sock::.

   * You have started the *Note `mysqld': mysqld. server with the
     `--socket=/path/to/socket' option, but forgotten to tell client
     programs the new name of the socket file. If you change the socket
     path name for the server, you must also notify the MySQL clients.
     You can do this by providing the same `--socket' option when you
     run client programs. You also need to ensure that clients have
     permission to access the `mysql.sock' file. To find out where the
     socket file is, you can do:

          shell> netstat -ln | grep mysql

     See *Note problems-with-mysql-sock::.

   * You are using Linux and one server thread has died (dumped core).
     In this case, you must kill the other *Note `mysqld': mysqld.
     threads (for example, with *Note `kill': kill. or with the *Note
     `mysql_zap': mysql-zap. script) before you can restart the MySQL
     server. See *Note crashing::.

   * The server or client program might not have the proper access
     privileges for the directory that holds the Unix socket file or
     the socket file itself. In this case, you must either change the
     access privileges for the directory or socket file so that the
     server and clients can access them, or restart *Note `mysqld':
     mysqld. with a `--socket' option that specifies a socket file name
     in a directory where the server can create it and where client
     programs can access it.

If you get the error message `Can't connect to MySQL server on
some_host', you can try the following things to find out what the
problem is:

   * Check whether the server is running on that host by executing
     `telnet some_host 3306' and pressing the Enter key a couple of
     times. (3306 is the default MySQL port number. Change the value if
     your server is listening to a different port.) If there is a MySQL
     server running and listening to the port, you should get a
     response that includes the server's version number. If you get an
     error such as `telnet: Unable to connect to remote host:
     Connection refused', then there is no server running on the given
     port.

   * If the server is running on the local host, try using *Note
     `mysqladmin -h localhost variables': mysqladmin. to connect using
     the Unix socket file. Verify the TCP/IP port number that the
     server is configured to listen to (it is the value of the `port'
     variable.)

   * If you are running under Linux and Security-Enhanced Linux
     (SELinux) is enabled, make sure you have disabled SELinux
     protection for the `mysqld' process.


File: manual.info,  Node: can-not-connect-to-server-on-windows,  Prev: can-not-connect-to-server,  Up: can-not-connect-to-server

C.5.2.3 `Connection to MySQL Server Failing on Windows'
.......................................................

When you're running a MySQL server on Windows with many TCP/IP
connections to it, and you're experiencing that quite often your
clients get a `Can't connect to MySQL server' error, the reason might
be that Windows does not allow for enough ephemeral (short-lived) ports
to serve those connections.

The purpose of `TIME_WAIT' is to keep a connection accepting packets
even after the connection has been closed. This is because Internet
routing can cause a packet to take a slow route to its destination and
it may arrive after both sides have agreed to close. If the port is in
use for a new connection, that packet from the old connection could
break the protocol or compromise personal information from the original
connection. The `TIME_WAIT' delay prevents this by ensuring that the
port cannot be reused until after some time has been permitted for
those delayed packets to arrive.

It is safe to reduce `TIME_WAIT' greatly on LAN connections because
there is little chance of packets arriving at very long delays, as they
could through the Internet with its comparatively large distances and
latencies.

Windows permits ephemeral (short-lived) TCP ports to the user. After
any port is closed it will remain in a `TIME_WAIT' status for 120
seconds. The port will not be available again until this time expires.
The default range of port numbers depends on the version of Windows,
with a more limited number of ports in older versions:

   * Windows through Server 2003: Ports in range 1025-5000

   * Windows Vista, Server 2008, and newer: Ports in range 49152-65535

With a small stack of available TCP ports (5000) and a high number of
TCP ports being open and closed over a short period of time along with
the `TIME_WAIT' status you have a good chance for running out of ports.
There are two ways to address this problem:

   * Reduce the number of TCP ports consumed quickly by investigating
     connection pooling or persistent connections where possible

   * Tune some settings in the Windows registry (see below)

* IMPORTANT: The following procedure involves modifying the Windows
registry. Before you modify the registry, make sure to back it up and
make sure that you understand how to restore the registry if a problem
occurs.  For information about how to back up, restore, and edit the
registry, view the following article in the Microsoft Knowledge Base:
`http://support.microsoft.com/kb/256986/EN-US/'.  *

  1. Start Registry Editor (`Regedt32.exe').

  2. Locate the following key in the registry:

          HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\Tcpip\Parameters

  3. On the `Edit' menu, click `Add Value', and then add the following
     registry value:

          Value Name: MaxUserPort
          Data Type: REG_DWORD
          Value: 65534

     This sets the number of ephemeral ports available to any user. The
     valid range is between 5000 and 65534 (decimal). The default value
     is 0x1388 (5000 decimal).

  4. On the `Edit' menu, click `Add Value', and then add the following
     registry value:

          Value Name: TcpTimedWaitDelay
          Data Type: REG_DWORD
          Value: 30

     This sets the number of seconds to hold a TCP port connection in
     `TIME_WAIT' state before closing. The valid range is between 0
     (zero) and 300 (decimal). The default value is 0x78 (120 decimal).

  5. Quit Registry Editor.

  6. Reboot the machine.

Note: Undoing the above should be as simple as deleting the registry
entries you've created.


File: manual.info,  Node: error-lost-connection,  Next: old-client,  Prev: can-not-connect-to-server,  Up: common-errors

C.5.2.4 `Lost connection to MySQL server'
.........................................

There are three likely causes for this error message.

Usually it indicates network connectivity trouble and you should check
the condition of your network if this error occurs frequently. If the
error message includes `during query,' this is probably the case you
are experiencing.

Sometimes the `during query' form happens when millions of rows are
being sent as part of one or more queries. If you know that this is
happening, you should try increasing `net_read_timeout' from its
default of 30 seconds to 60 seconds or longer, sufficient for the data
transfer to complete.

More rarely, it can happen when the client is attempting the initial
connection to the server. In this case, if your `connect_timeout' value
is set to only a few seconds, you may be able to resolve the problem by
increasing it to ten seconds, perhaps more if you have a very long
distance or slow connection. You can determine whether you are
experiencing this more uncommon cause by using `SHOW GLOBAL STATUS LIKE
'Aborted_connects''.  It will increase by one for each initial
connection attempt that the server aborts. You may see `reading
authorization packet' as part of the error message; if so, that also
suggests that this is the solution that you need.

If the cause is none of those just described, you may be experiencing a
problem with *Note `BLOB': blob. values that are larger than
`max_allowed_packet', which can cause this error with some clients.
Sometime you may see `packet too large' as part of the error message,
and that confirms that you need to increase `max_allowed_packet'.


File: manual.info,  Node: old-client,  Next: password-too-long,  Prev: error-lost-connection,  Up: common-errors

C.5.2.5 `Client does not support authentication protocol'
.........................................................

MySQL 5.0 uses an authentication protocol based on a password hashing
algorithm that is incompatible with that used by older (pre-4.1)
clients. If you upgrade the server from 4.0, attempts to connect to it
with an older client may fail with the following message:

     shell> mysql
     Client does not support authentication protocol requested
     by server; consider upgrading MySQL client

To solve this problem, you should use one of the following approaches:

   * Upgrade all client programs to use a 4.1.1 or newer client library.

   * When connecting to the server with a pre-4.1 client program, use
     an account that still has a pre-4.1-style password.

   * Reset the password to pre-4.1 style for each user that needs to
     use a pre-4.1 client program. This can be done using the *Note
     `SET PASSWORD': set-password.  statement and the `OLD_PASSWORD()'
     function:

          mysql> SET PASSWORD FOR
              -> 'SOME_USER'@'SOME_HOST' = OLD_PASSWORD('NEWPWD');

     Alternatively, use *Note `UPDATE': update.  and *Note `FLUSH
     PRIVILEGES': flush.:

          mysql> UPDATE mysql.user SET Password = OLD_PASSWORD('NEWPWD')
              -> WHERE Host = 'SOME_HOST' AND User = 'SOME_USER';
          mysql> FLUSH PRIVILEGES;

     Substitute the password you want to use for `NEWPWD' in the
     preceding examples. MySQL cannot tell you what the original
     password was, so you'll need to pick a new one.

   * Tell the server to use the older password hashing algorithm:

       1. Start *Note `mysqld': mysqld. with the `--old-passwords'
          option.

       2. Assign an old-format password to each account that has had
          its password updated to the longer 4.1 format. You can
          identify these accounts with the following query:

               mysql> SELECT Host, User, Password FROM mysql.user
                   -> WHERE LENGTH(Password) > 16;

          For each account record displayed by the query, use the
          `Host' and `User' values and assign a password using the
          `OLD_PASSWORD()' function and either *Note `SET PASSWORD':
          set-password.  or *Note `UPDATE': update, as described
          earlier.

*Note*:

In older versions of PHP, the `mysql' extension does not support the
authentication protocol in MySQL 4.1.1 and higher. This is true
regardless of the PHP version being used. If you wish to use the
`mysql' extension with MySQL 4.1 or newer, you may need to follow one
of the options discussed above for configuring MySQL to work with old
clients. The `mysqli' extension (stands for "MySQL, Improved"; added in
PHP 5) is compatible with the improved password hashing employed in
MySQL 4.1 and higher, and no special configuration of MySQL need be
done to use this MySQL client library. For more information about the
`mysqli' extension, see `http://php.net/mysqli'.

It may also be possible to compile the older `mysql' extension against
the new MySQL client library. This is beyond the scope of this Manual;
consult the PHP documentation for more information. You also be able to
obtain assistance with these issues in our MySQL with PHP forum
(http://forums.mysql.com/list.php?52).

For additional background on password hashing and authentication, see
*Note password-hashing::.


File: manual.info,  Node: password-too-long,  Next: blocked-host,  Prev: old-client,  Up: common-errors

C.5.2.6 Password Fails When Entered Interactively
.................................................

MySQL client programs prompt for a password when invoked with a
`--password' or `-p' option that has no following password value:

     shell> mysql -u USER_NAME -p
     Enter password:

On some systems, you may find that your password works when specified
in an option file or on the command line, but not when you enter it
interactively at the `Enter password:' prompt. This occurs when the
library provided by the system to read passwords limits password values
to a small number of characters (typically eight). That is a problem
with the system library, not with MySQL. To work around it, change your
MySQL password to a value that is eight or fewer characters long, or
put your password in an option file.


File: manual.info,  Node: blocked-host,  Next: too-many-connections,  Prev: password-too-long,  Up: common-errors

C.5.2.7 `Host 'HOST_NAME' is blocked'
.....................................

If you get the following error, it means that *Note `mysqld': mysqld.
has received many connect requests from the host `'HOST_NAME'' that
have been interrupted in the middle:

     Host 'HOST_NAME' is blocked because of many connection errors.
     Unblock with 'mysqladmin flush-hosts'

The number of interrupted connect requests permitted is determined by
the value of the `max_connect_errors' system variable. After
`max_connect_errors' failed requests, *Note `mysqld': mysqld. assumes
that something is wrong (for example, that someone is trying to break
in), and blocks the host from further connections until you execute a
*Note `mysqladmin flush-hosts': mysqladmin. command or issue a *Note
`FLUSH HOSTS': flush.  statement. See *Note server-system-variables::.

By default, *Note `mysqld': mysqld. blocks a host after 10 connection
errors. You can adjust the value by starting the server like this:

     shell> mysqld_safe --max_connect_errors=10000 &

If you get this error message for a given host, you should first verify
that there isn't anything wrong with TCP/IP connections from that host.
If you are having network problems, it does you no good to increase the
value of the `max_connect_errors' variable.


File: manual.info,  Node: too-many-connections,  Next: out-of-memory,  Prev: blocked-host,  Up: common-errors

C.5.2.8 `Too many connections'
..............................

If you get a `Too many connections' error when you try to connect to
the *Note `mysqld': mysqld.  server, this means that all available
connections are in use by other clients.

The number of connections permitted is controlled by the
`max_connections' system variable. Its default value is 100. If you
need to support more connections, you should set a larger value for this
variable.

*Note `mysqld': mysqld. actually permits `max_connections+1' clients to
connect. The extra connection is reserved for use by accounts that have
the `SUPER' privilege. By granting the `SUPER' privilege to
administrators and not to normal users (who should not need it), an
administrator can connect to the server and use *Note `SHOW
PROCESSLIST': show-processlist. to diagnose problems even if the
maximum number of unprivileged clients are connected. See *Note
show-processlist::.

The maximum number of connections MySQL can support depends on the
quality of the thread library on a given platform, the amount of RAM
available, how much RAM is used for each connection, the workload from
each connection, and the desired response time. Linux or Solaris should
be able to support at 500 to 1000 simultaneous connections routinely
and as many as 10,000 connections if you have many gigabytes of RAM
available and the workload from each is low or the response time target
undemanding. Windows is limited to (open tables x 2 + open connections)
< 2048 due to the Posix compatibility layer used on that platform.

Increasing `open-files-limit' may be necessary. Also see *Note
linux-postinstallation::, for how to raise the operating system limit
on how many handles can be used by MySQL.


File: manual.info,  Node: out-of-memory,  Next: gone-away,  Prev: too-many-connections,  Up: common-errors

C.5.2.9 `Out of memory'
.......................

If you issue a query using the *Note `mysql': mysql. client program and
receive an error like the following one, it means that *Note `mysql':
mysql. does not have enough memory to store the entire query result:

     mysql: Out of memory at line 42, 'malloc.c'
     mysql: needed 8136 byte (8k), memory in use: 12481367 bytes (12189k)
     ERROR 2008: MySQL client ran out of memory

To remedy the problem, first check whether your query is correct. Is it
reasonable that it should return so many rows?  If not, correct the
query and try again. Otherwise, you can invoke *Note `mysql': mysql.
with the `--quick' option. This causes it to use the *Note
`mysql_use_result()': mysql-use-result.  C API function to retrieve the
result set, which places less of a load on the client (but more on the
server).


File: manual.info,  Node: gone-away,  Next: packet-too-large,  Prev: out-of-memory,  Up: common-errors

C.5.2.10 `MySQL server has gone away'
.....................................

This section also covers the related `Lost connection to server during
query' error.

The most common reason for the `MySQL server has gone away' error is
that the server timed out and closed the connection. In this case, you
normally get one of the following error codes (which one you get is
operating system-dependent).

Error Code                Description
`CR_SERVER_GONE_ERROR'    The client couldn't send a question to the
                          server.
`CR_SERVER_LOST'          The client didn't get an error when writing to
                          the server, but it didn't get a full answer
                          (or any answer) to the question.

By default, the server closes the connection after eight hours if
nothing has happened. You can change the time limit by setting the
`wait_timeout' variable when you start *Note `mysqld': mysqld. See
*Note server-system-variables::.

If you have a script, you just have to issue the query again for the
client to do an automatic reconnection. This assumes that you have
automatic reconnection in the client enabled (which is the default for
the `mysql' command-line client).

Some other common reasons for the `MySQL server has gone away' error
are:

   * You (or the db administrator) has killed the running thread with a
     *Note `KILL': kill.  statement or a *Note `mysqladmin kill':
     mysqladmin. command.

   * You tried to run a query after closing the connection to the
     server. This indicates a logic error in the application that
     should be corrected.

   * A client application running on a different host does not have the
     necessary privileges to connect to the MySQL server from that host.

   * You got a timeout from the TCP/IP connection on the client side.
     This may happen if you have been using the commands: *Note
     `mysql_options(..., MYSQL_OPT_READ_TIMEOUT,...)': mysql-options. or
     *Note `mysql_options(..., MYSQL_OPT_WRITE_TIMEOUT,...)':
     mysql-options. In this case increasing the timeout may help solve
     the problem.

   * You have encountered a timeout on the server side and the
     automatic reconnection in the client is disabled (the `reconnect'
     flag in the `MYSQL' structure is equal to 0).

   * You are using a Windows client and the server had dropped the
     connection (probably because `wait_timeout' expired) before the
     command was issued.

     The problem on Windows is that in some cases MySQL doesn't get an
     error from the OS when writing to the TCP/IP connection to the
     server, but instead gets the error when trying to read the answer
     from the connection.

     Prior to MySQL 5.0.19, even if the `reconnect' flag in the `MYSQL'
     structure is equal to 1, MySQL does not automatically reconnect
     and re-issue the query as it doesn't know if the server did get
     the original query or not.

     The solution to this is to either do a *Note `mysql_ping()':
     mysql-ping. on the connection if there has been a long time since
     the last query (this is what Connector/ODBC does) or set
     `wait_timeout' on the *Note `mysqld': mysqld. server so high that
     it in practice never times out.

   * You can also get these errors if you send a query to the server
     that is incorrect or too large. If *Note `mysqld': mysqld.
     receives a packet that is too large or out of order, it assumes
     that something has gone wrong with the client and closes the
     connection. If you need big queries (for example, if you are
     working with big *Note `BLOB': blob. columns), you can increase
     the query limit by setting the server's `max_allowed_packet'
     variable, which has a default value of 1MB. You may also need to
     increase the maximum packet size on the client end. More
     information on setting the packet size is given in *Note
     packet-too-large::.

     An *Note `INSERT': insert. or *Note `REPLACE': replace. statement
     that inserts a great many rows can also cause these sorts of
     errors. Either one of these statements sends a single request to
     the server irrespective of the number of rows to be inserted;
     thus, you can often avoid the error by reducing the number of rows
     sent per *Note `INSERT': insert. or *Note `REPLACE': replace.

   * You also get a lost connection if you are sending a packet 16MB or
     larger if your client is older than 4.0.8 and your server is 4.0.8
     and above, or the other way around.

   * It is also possible to see this error if host name lookups fail
     (for example, if the DNS server on which your server or network
     relies goes down). This is because MySQL is dependent on the host
     system for name resolution, but has no way of knowing whether it
     is working--from MySQL's point of view the problem is
     indistinguishable from any other network timeout.

     You may also see the `MySQL server has gone away' error if MySQL
     is started with the `--skip-networking' option.

     Another networking issue that can cause this error occurs if the
     MySQL port (default 3306) is blocked by your firewall, thus
     preventing any connections at all to the MySQL server.

   * You can also encounter this error with applications that fork
     child processes, all of which try to use the same connection to
     the MySQL server. This can be avoided by using a separate
     connection for each child process.

   * You have encountered a bug where the server died while executing
     the query.

You can check whether the MySQL server died and restarted by executing
*Note `mysqladmin version': mysqladmin. and examining the server's
uptime. If the client connection was broken because *Note `mysqld':
mysqld. crashed and restarted, you should concentrate on finding the
reason for the crash. Start by checking whether issuing the query again
kills the server again. See *Note crashing::.

You can get more information about the lost connections by starting
*Note `mysqld': mysqld. with the `--log-warnings=2' option. This logs
some of the disconnected errors in the `hostname.err' file. See *Note
error-log::.

If you want to create a bug report regarding this problem, be sure that
you include the following information:

   * Indicate whether the MySQL server died. You can find information
     about this in the server error log. See *Note crashing::.

   * If a specific query kills *Note `mysqld': mysqld. and the tables
     involved were checked with *Note `CHECK TABLE': check-table.
     before you ran the query, can you provide a reproducible test
     case? See MySQL Internals: Porting
     (http://forge.mysql.com/wiki/MySQL_Internals_Porting).

   * What is the value of the `wait_timeout' system variable in the
     MySQL server? (*Note `mysqladmin variables': mysqladmin. gives you
     the value of this variable.)

   * Have you tried to run *Note `mysqld': mysqld. with the general
     query log enabled to determine whether the problem query appears
     in the log? (See *Note query-log::.)

See also *Note communication-errors::, and *Note bug-reports::.


File: manual.info,  Node: packet-too-large,  Next: communication-errors,  Prev: gone-away,  Up: common-errors

C.5.2.11 `Packet too large'
...........................

A communication packet is a single SQL statement sent to the MySQL
server, a single row that is sent to the client, or a binary log event
sent from a master replication server to a slave.

The largest possible packet that can be transmitted to or from a MySQL
5.0 server or client is 1GB.

When a MySQL client or the *Note `mysqld': mysqld. server receives a
packet bigger than `max_allowed_packet' bytes, it issues a `Packet too
large' error and closes the connection. With some clients, you may also
get a `Lost connection to MySQL server during query' error if the
communication packet is too large.

Both the client and the server have their own `max_allowed_packet'
variable, so if you want to handle big packets, you must increase this
variable both in the client and in the server.

If you are using the *Note `mysql': mysql. client program, its default
`max_allowed_packet' variable is 16MB. To set a larger value, start
*Note `mysql': mysql.  like this:

     shell> mysql --max_allowed_packet=32M

That sets the packet size to 32MB.

The server's default `max_allowed_packet' value is 1MB. You can
increase this if the server needs to handle big queries (for example,
if you are working with big *Note `BLOB': blob. columns). For example,
to set the variable to 16MB, start the server like this:

     shell> mysqld --max_allowed_packet=16M

You can also use an option file to set `max_allowed_packet'. For
example, to set the size for the server to 16MB, add the following
lines in an option file:

     [mysqld]
     max_allowed_packet=16M

It is safe to increase the value of this variable because the extra
memory is allocated only when needed. For example, *Note `mysqld':
mysqld. allocates more memory only when you issue a long query or when
*Note `mysqld': mysqld. must return a large result row. The small
default value of the variable is a precaution to catch incorrect
packets between the client and server and also to ensure that you do
not run out of memory by using large packets accidentally.

You can also get strange problems with large packets if you are using
large *Note `BLOB': blob. values but have not given *Note `mysqld':
mysqld. access to enough memory to handle the query. If you suspect
this is the case, try adding `ulimit -d 256000' to the beginning of the
*Note `mysqld_safe': mysqld-safe. script and restarting *Note `mysqld':
mysqld.


File: manual.info,  Node: communication-errors,  Next: full-table,  Prev: packet-too-large,  Up: common-errors

C.5.2.12 Communication Errors and Aborted Connections
.....................................................

The server error log can be a useful source of information about
connection problems. See *Note error-log::. If you start the server
with the `--log-warnings' option, you might find messages like this in
your error log:

     010301 14:38:23  Aborted connection 854 to db: 'users' user: 'josh'

If a client successfully connects but later disconnects improperly or
is terminated, the server increments the `Aborted_clients' status
variable, and logs an `Aborted connection' message to the error log.
The cause can be any of the following:

   * The client program did not call *Note `mysql_close()':
     mysql-close. before exiting.

   * The client had been sleeping more than `wait_timeout' or
     `interactive_timeout' seconds without issuing any requests to the
     server. See *Note server-system-variables::.

   * The client program ended abruptly in the middle of a data transfer.

If a client is unable even to connect, the server increments the
`Aborted_connects' status variable. Unsuccessful connect attempts can
occur for the following reasons:

   * A client doesn't have privileges to connect to a database.

   * A client uses an incorrect password.

   * A connection packet doesn't contain the right information.

   * It takes more than `connect_timeout' seconds to get a connect
     packet. See *Note server-system-variables::.

If these kinds of things happen, it might indicate that someone is
trying to break into your server! Messages for these types of problems
are logged to the general query log if it is enabled.

Other reasons for problems with aborted clients or aborted connections:

   * Use of Ethernet protocol with Linux, both half and full duplex.
     Many Linux Ethernet drivers have this bug. You should test for
     this bug by transferring a huge file using FTP between the client
     and server machines. If a transfer goes in burst-pause-burst-pause
     mode, you are experiencing a Linux duplex syndrome. The only
     solution is switching the duplex mode for both your network card
     and hub/switch to either full duplex or to half duplex and testing
     the results to determine the best setting.

   * Some problem with the thread library that causes interrupts on
     reads.

   * Badly configured TCP/IP.

   * Faulty Ethernets, hubs, switches, cables, and so forth.  This can
     be diagnosed properly only by replacing hardware.

   * The `max_allowed_packet' variable value is too small or queries
     require more memory than you have allocated for *Note `mysqld':
     mysqld. See *Note packet-too-large::.

See also *Note gone-away::.


File: manual.info,  Node: full-table,  Next: cannot-create,  Prev: communication-errors,  Up: common-errors

C.5.2.13 `The table is full'
............................

If a table-full error occurs, it may be that the disk is full or that
the table has reached its maximum size. The effective maximum table
size for MySQL databases is usually determined by operating system
constraints on file sizes, not by MySQL internal limits. See *Note
table-size-limit::.


File: manual.info,  Node: cannot-create,  Next: commands-out-of-sync,  Prev: full-table,  Up: common-errors

C.5.2.14 `Can't create/write to file'
.....................................

If you get an error of the following type for some queries, it means
that MySQL cannot create a temporary file for the result set in the
temporary directory:

     Can't create/write to file '\\sqla3fe_0.ism'.

The preceding error is a typical message for Windows; the Unix message
is similar.

One fix is to start *Note `mysqld': mysqld. with the `--tmpdir' option
or to add the option to the `[mysqld]' section of your option file. For
example, to specify a directory of `C:\temp', use these lines:

     [mysqld]
     tmpdir=C:/temp

The `C:\temp' directory must exist and have sufficient space for the
MySQL server to write to. See *Note option-files::.

Another cause of this error can be permissions issues. Make sure that
the MySQL server can write to the `tmpdir' directory.

Check also the error code that you get with *Note `perror': perror. One
reason the server cannot write to a table is that the file system is
full:

     shell> perror 28
     OS error code  28:  No space left on device

If you get an error of the following type during startup, it indicates
that the file system or directory used for storing data files is write
protected. Providing the write error is to a test file, This error is
not serious and can be safely ignored.

     Can't create test file /usr/local/mysql/data/master.lower-test


File: manual.info,  Node: commands-out-of-sync,  Next: ignoring-user,  Prev: cannot-create,  Up: common-errors

C.5.2.15 `Commands out of sync'
...............................

If you get `Commands out of sync; you can't run this command now' in
your client code, you are calling client functions in the wrong order.

This can happen, for example, if you are using *Note
`mysql_use_result()': mysql-use-result. and try to execute a new query
before you have called *Note `mysql_free_result()': mysql-free-result.
It can also happen if you try to execute two queries that return data
without calling *Note `mysql_use_result()': mysql-use-result. or *Note
`mysql_store_result()': mysql-store-result. in between.


File: manual.info,  Node: ignoring-user,  Next: cannot-find-table,  Prev: commands-out-of-sync,  Up: common-errors

C.5.2.16 `Ignoring user'
........................

If you get the following error, it means that when *Note `mysqld':
mysqld. was started or when it reloaded the grant tables, it found an
account in the `user' table that had an invalid password.

`Found wrong password for user 'SOME_USER'@'SOME_HOST'; ignoring user'

As a result, the account is simply ignored by the permission system.

The following list indicates possible causes of and fixes for this
problem:

   * You may be running a new version of *Note `mysqld': mysqld. with
     an old `user' table. You can check this by executing *Note
     `mysqlshow mysql user': mysqlshow. to see whether the `Password'
     column is shorter than 16 characters. If so, you can correct this
     condition by running the `scripts/add_long_password' script.

   * The account has an old password (eight characters long).  Update
     the account in the `user' table to have a new password.

   * You have specified a password in the `user' table without using the
     `PASSWORD()' function. Use *Note `mysql': mysql. to update the
     account in the `user' table with a new password, making sure to
     use the `PASSWORD()' function:

          mysql> UPDATE user SET Password=PASSWORD('NEWPWD')
              -> WHERE User='SOME_USER' AND Host='SOME_HOST';


File: manual.info,  Node: cannot-find-table,  Next: cannot-initialize-character-set,  Prev: ignoring-user,  Up: common-errors

C.5.2.17 `Table 'TBL_NAME' doesn't exist'
.........................................

If you get either of the following errors, it usually means that no
table exists in the default database with the given name:

     Table 'TBL_NAME' doesn't exist
     Can't find file: 'TBL_NAME' (errno: 2)

In some cases, it may be that the table does exist but that you are
referring to it incorrectly:

   * Because MySQL uses directories and files to store databases and
     tables, database and table names are case sensitive if they are
     located on a file system that has case-sensitive file names.

   * Even for file systems that are not case sensitive, such as on
     Windows, all references to a given table within a query must use
     the same lettercase.

You can check which tables are in the default database with *Note `SHOW
TABLES': show-tables. See *Note show::.


File: manual.info,  Node: cannot-initialize-character-set,  Next: not-enough-file-handles,  Prev: cannot-find-table,  Up: common-errors

C.5.2.18 `Can't initialize character set'
.........................................

You might see an error like this if you have character set problems:

     MySQL Connection Failed: Can't initialize character set CHARSET_NAME

This error can have any of the following causes:

   * The character set is a multi-byte character set and you have no
     support for the character set in the client. In this case, you
     need to recompile the client by running `configure' with the
     `--with-charset=CHARSET_NAME' or
     `--with-extra-charsets=CHARSET_NAME' option. See *Note
     source-configuration-options::.

     All standard MySQL binaries are compiled with
     `--with-extra-charsets=complex' or (for Windows)
     `--with-extra-charsets=complex', which enables support for all
     multi-byte character sets.  See *Note
     source-configuration-options::.

   * The character set is a simple character set that is not compiled
     into *Note `mysqld': mysqld, and the character set definition
     files are not in the place where the client expects to find them.

     In this case, you need to use one of the following methods to
     solve the problem:

        * Recompile the client with support for the character set. See
          *Note source-configuration-options::.

        * Specify to the client the directory where the character set
          definition files are located. For many clients, you can do
          this with the `--character-sets-dir' option.

        * Copy the character definition files to the path where the
          client expects them to be.


File: manual.info,  Node: not-enough-file-handles,  Next: table-corruption,  Prev: cannot-initialize-character-set,  Up: common-errors

C.5.2.19 `'FILE' Not Found' and Similar Errors
..............................................

If you get `ERROR '...' not found (errno: 23)', `Can't open file: ...
(errno: 24)', or any other error with `errno 23' or `errno 24' from
MySQL, it means that you haven't allocated enough file descriptors for
the MySQL server. You can use the *Note `perror': perror.  utility to
get a description of what the error number means:

     shell> perror 23
     OS error code  23:  File table overflow
     shell> perror 24
     OS error code  24:  Too many open files
     shell> perror 11
     OS error code  11:  Resource temporarily unavailable

The problem here is that *Note `mysqld': mysqld. is trying to keep open
too many files simultaneously. You can either tell *Note `mysqld':
mysqld. not to open so many files at once or increase the number of
file descriptors available to *Note `mysqld': mysqld.

To tell *Note `mysqld': mysqld. to keep open fewer files at a time, you
can make the table cache smaller by reducing the value of the
`table_cache' system variable (the default value is 64). This may not
entirely prevent running out of file descriptors because in some
circumstances the server may attempt to extend the cache size
temporarily, as described in *Note table-cache::. Reducing the value of
`max_connections' also reduces the number of open files (the default
value is 100).

To change the number of file descriptors available to *Note `mysqld':
mysqld, you can use the `--open-files-limit' option to *Note
`mysqld_safe': mysqld-safe. or set the `open_files_limit' system
variable. See *Note server-system-variables::. The easiest way to set
these values is to add an option to your option file. See *Note
option-files::. If you have an old version of *Note `mysqld': mysqld.
that doesn't support setting the open files limit, you can edit the
*Note `mysqld_safe': mysqld-safe. script. There is a commented-out line
`ulimit -n 256' in the script. You can remove the ``#'' character to
uncomment this line, and change the number `256' to set the number of
file descriptors to be made available to *Note `mysqld': mysqld.

`--open-files-limit' and `ulimit' can increase the number of file
descriptors, but only up to the limit imposed by the operating system.
There is also a `hard' limit that can be overridden only if you start
*Note `mysqld_safe': mysqld-safe. or *Note `mysqld': mysqld. as `root'
(just remember that you also need to start the server with the `--user'
option in this case so that it does not continue to run as `root' after
it starts up). If you need to increase the operating system limit on
the number of file descriptors available to each process, consult the
documentation for your system.

*Note*:

If you run the `tcsh' shell, `ulimit' does not work!  `tcsh' also
reports incorrect values when you ask for the current limits. In this
case, you should start *Note `mysqld_safe': mysqld-safe. using `sh'.


File: manual.info,  Node: table-corruption,  Prev: not-enough-file-handles,  Up: common-errors

C.5.2.20 Table-Corruption Issues
................................

If you have started *Note `mysqld': mysqld. with `--myisam-recover',
MySQL automatically checks and tries to repair `MyISAM' tables if they
are marked as 'not closed properly' or 'crashed'. If this happens,
MySQL writes an entry in the `hostname.err' file `'Warning: Checking
table ...'' which is followed by `Warning: Repairing table' if the
table needs to be repaired. If you get a lot of these errors, without
*Note `mysqld': mysqld. having died unexpectedly just before, then
something is wrong and needs to be investigated further.

See also *Note server-options::, and *Note reproducible-test-case::.


File: manual.info,  Node: installation-issues,  Next: administration-issues,  Prev: common-errors,  Up: problems

C.5.3 Installation-Related Issues
---------------------------------

* Menu:

* file-permissions::             Problems with File Permissions


File: manual.info,  Node: file-permissions,  Prev: installation-issues,  Up: installation-issues

C.5.3.1 Problems with File Permissions
......................................

If you have problems with file permissions, the `UMASK' environment
variable might be set incorrectly when *Note `mysqld': mysqld. starts.
For example, MySQL might issue the following error message when you
create a table:

     ERROR: Can't find file: 'path/with/filename.frm' (Errcode: 13)

The default `UMASK' value is `0660'. You can change this behavior by
starting *Note `mysqld_safe': mysqld-safe. as follows:

     shell> UMASK=384  # = 600 in octal
     shell> export UMASK
     shell> mysqld_safe &

By default, MySQL creates database and `RAID' directories with an
access permission value of `0700'. You can modify this behavior by
setting the `UMASK_DIR' variable. If you set its value, new directories
are created with the combined `UMASK' and `UMASK_DIR' values. For
example, if you want to give group access to all new directories, you
can do this:

     shell> UMASK_DIR=504  # = 770 in octal
     shell> export UMASK_DIR
     shell> mysqld_safe &

MySQL assumes that the value for `UMASK' or `UMASK_DIR' is in octal if
it starts with a zero.

See *Note environment-variables::.


File: manual.info,  Node: administration-issues,  Next: query-issues,  Prev: installation-issues,  Up: problems

C.5.4 Administration-Related Issues
-----------------------------------

* Menu:

* resetting-permissions::        How to Reset the Root Password
* crashing::                     What to Do If MySQL Keeps Crashing
* full-disk::                    How MySQL Handles a Full Disk
* temporary-files::              Where MySQL Stores Temporary Files
* problems-with-mysql-sock::     How to Protect or Change the MySQL Unix Socket File
* timezone-problems::            Time Zone Problems


File: manual.info,  Node: resetting-permissions,  Next: crashing,  Prev: administration-issues,  Up: administration-issues

C.5.4.1 How to Reset the Root Password
......................................

* Menu:

* resetting-permissions-windows::  Resetting the Root Password: Windows Systems
* resetting-permissions-unix::   Resetting the Root Password: Unix Systems
* resetting-permissions-generic::  Resetting the Root Password: Generic Instructions

If you have never set a `root' password for MySQL, the server does not
require a password at all for connecting as `root'. However, this is
insecure. For instructions on assigning passwords, see *Note
default-privileges::.

If you know the `root' password, but want to change it, see *Note
set-password::.

If you set a `root' password previously, but have forgotten it, you can
set a new password. The following sections provide instructions for
Windows and Unix systems, as well as generic instructions that apply to
any system.


File: manual.info,  Node: resetting-permissions-windows,  Next: resetting-permissions-unix,  Prev: resetting-permissions,  Up: resetting-permissions

C.5.4.2 Resetting the Root Password: Windows Systems
....................................................

On Windows, use the following procedure to reset the password for all
MySQL `root' accounts:

  1. Log on to your system as Administrator.

  2. Stop the MySQL server if it is running. For a server that is
     running as a Windows service, go to the Services manager: From the
     `Start' menu, select `Control Panel', then `Administrative Tools',
     then `Services'. Find the MySQL service in the list and stop it.

     If your server is not running as a service, you may need to use
     the Task Manager to force it to stop.

  3. Create a text file containing the following statements.  Replace
     the password with the password that you want to use.

          UPDATE mysql.user SET Password=PASSWORD('MyNewPass') WHERE User='root';
          FLUSH PRIVILEGES;

     Write the *Note `UPDATE': update. and *Note `FLUSH': flush.
     statements each on a single line. The *Note `UPDATE': update.
     statement resets the password for all `root' accounts, and the
     *Note `FLUSH': flush. statement tells the server to reload the
     grant tables into memory so that it notices the password change.

  4. Save the file. For this example, the file will be named
     `C:\mysql-init.txt'.

  5. Open a console window to get to the command prompt: From the
     `Start' menu, select `Run', then enter `cmd' as the command to be
     run.

  6. Start the MySQL server with the special `--init-file' option
     (notice that the backslash in the option value is doubled):

          C:\> C:\mysql\bin\mysqld-nt --init-file=C:\\mysql-init.txt

     If you installed MySQL to a location other than `C:\mysql', adjust
     the command accordingly.

     The server executes the contents of the file named by the
     `--init-file' option at startup, changing each `root' account
     password.

     You can also add the `--console' option to the command if you want
     server output to appear in the console window rather than in a log
     file.

     If you installed MySQL using the MySQL Installation Wizard, you
     may need to specify a `--defaults-file' option:

          C:\> "C:\Program Files\MySQL\MySQL Server 5.0\bin\mysqld-nt.exe"
                   --defaults-file="C:\\Program Files\\MySQL\\MySQL Server 5.0\\my.ini"
                   --init-file=C:\\mysql-init.txt

     The appropriate `--defaults-file' setting can be found using the
     Services Manager: From the `Start' menu, select `Control Panel',
     then `Administrative Tools', then `Services'. Find the MySQL
     service in the list, right-click it, and choose the `Properties'
     option. The `Path to executable' field contains the
     `--defaults-file' setting.

  7. After the server has started successfully, delete
     `C:\mysql-init.txt'.

You should now be able to connect to the MySQL server as `root' using
the new password. Stop the MySQL server, then restart it in normal mode
again. If you run the server as a service, start it from the Windows
Services window. If you start the server manually, use whatever command
you normally use.


File: manual.info,  Node: resetting-permissions-unix,  Next: resetting-permissions-generic,  Prev: resetting-permissions-windows,  Up: resetting-permissions

C.5.4.3 Resetting the Root Password: Unix Systems
.................................................

On Unix, use the following procedure to reset the password for all
MySQL `root' accounts. The instructions assume that you will start the
server so that it runs using the Unix login account that you normally
use for running the server. For example, if you run the server using
the `mysql' login account, you should log in as `mysql' before using the
instructions. Alternatively, you can log in as `root', but in this case
you _must_ start *Note `mysqld': mysqld.  with the `--user=mysql'
option.  If you start the server as `root' without using
`--user=mysql', the server may create `root'-owned files in the data
directory, such as log files, and these may cause permission-related
problems for future server startups. If that happens, you will need to
either change the ownership of the files to `mysql' or remove them.

  1. Log on to your system as the Unix user that the *Note `mysqld':
     mysqld. server runs as (for example, `mysql').

  2. Locate the `.pid' file that contains the server's process ID. The
     exact location and name of this file depend on your distribution,
     host name, and configuration. Common locations are
     `/var/lib/mysql/', `/var/run/mysqld/', and
     `/usr/local/mysql/data/'. Generally, the file name has an
     extension of `.pid' and begins with either `mysqld' or your
     system's host name.

     You can stop the MySQL server by sending a normal `kill' (not
     `kill -9') to the *Note `mysqld': mysqld. process, using the path
     name of the `.pid' file in the following command:

          shell> kill `cat /mysql-data-directory/host_name.pid`

     Use backticks (not forward quotation marks) with the `cat'
     command. These cause the output of `cat' to be substituted into the
     `kill' command.

  3. Create a text file containing the following statements.  Replace
     the password with the password that you want to use.

          UPDATE mysql.user SET Password=PASSWORD('MyNewPass') WHERE User='root';
          FLUSH PRIVILEGES;

     Write the *Note `UPDATE': update. and *Note `FLUSH': flush.
     statements each on a single line. The *Note `UPDATE': update.
     statement resets the password for all `root' accounts, and the
     *Note `FLUSH': flush. statement tells the server to reload the
     grant tables into memory so that it notices the password change.

  4. Save the file. For this example, the file will be named
     `/home/me/mysql-init'. The file contains the password, so it
     should not be saved where it can be read by other users. If you
     are not logged in as `mysql' (the user the server runs as), make
     sure that the file has permissions that permit `mysql' to read it.

  5. Start the MySQL server with the special `--init-file' option:

          shell> mysqld_safe --init-file=/home/me/mysql-init &

     The server executes the contents of the file named by the
     `--init-file' option at startup, changing each `root' account
     password.

  6. After the server has started successfully, delete
     `/home/me/mysql-init'.

You should now be able to connect to the MySQL server as `root' using
the new password. Stop the server and restart it normally.


File: manual.info,  Node: resetting-permissions-generic,  Prev: resetting-permissions-unix,  Up: resetting-permissions

C.5.4.4 Resetting the Root Password: Generic Instructions
.........................................................

The preceding sections provide password-resetting instructions for
Windows and Unix systems. Alternatively, on any platform, you can set
the new password using the *Note `mysql': mysql. client (but this
approach is less secure):

  1. Stop *Note `mysqld': mysqld. and restart it with the
     `--skip-grant-tables' option. This enables anyone to connect
     without a password and with all privileges. Because this is
     insecure, you might want to use `--skip-grant-tables' in
     conjunction with `--skip-networking' to prevent remote clients
     from connecting.

  2. Connect to the *Note `mysqld': mysqld. server with this command:

          shell> mysql

  3. Issue the following statements in the *Note `mysql': mysql.
     client. Replace the password with the password that you want to
     use.

          mysql> UPDATE mysql.user SET Password=PASSWORD('MyNewPass')
              ->                   WHERE User='root';
          mysql> FLUSH PRIVILEGES;

     The *Note `FLUSH': flush. statement tells the server to reload the
     grant tables into memory so that it notices the password change.

You should now be able to connect to the MySQL server as `root' using
the new password. Stop the server, then restart it normally (without the
`--skip-grant-tables' and `--skip-networking' options).


File: manual.info,  Node: crashing,  Next: full-disk,  Prev: resetting-permissions,  Up: administration-issues

C.5.4.5 What to Do If MySQL Keeps Crashing
..........................................

Each MySQL version is tested on many platforms before it is released.
This doesn't mean that there are no bugs in MySQL, but if there are
bugs, they should be very few and can be hard to find. If you have a
problem, it always helps if you try to find out exactly what crashes
your system, because you have a much better chance of getting the
problem fixed quickly.

First, you should try to find out whether the problem is that the *Note
`mysqld': mysqld. server dies or whether your problem has to do with
your client. You can check how long your *Note `mysqld': mysqld. server
has been up by executing *Note `mysqladmin version': mysqladmin. If
*Note `mysqld': mysqld. has died and restarted, you may find the reason
by looking in the server's error log. See *Note error-log::.

On some systems, you can find in the error log a stack trace of where
*Note `mysqld': mysqld. died that you can resolve with the
`resolve_stack_dump' program. See MySQL Internals: Porting
(http://forge.mysql.com/wiki/MySQL_Internals_Porting). Note that the
variable values written in the error log may not always be 100% correct.

Many server crashes are caused by corrupted data files or index files.
MySQL updates the files on disk with the `write()' system call after
every SQL statement and before the client is notified about the result.
(This is not true if you are running with `--delay-key-write', in which
case data files are written but not index files.) This means that data
file contents are safe even if *Note `mysqld': mysqld. crashes, because
the operating system ensures that the unflushed data is written to
disk. You can force MySQL to flush everything to disk after every SQL
statement by starting *Note `mysqld': mysqld. with the `--flush' option.

The preceding means that normally you should not get corrupted tables
unless one of the following happens:

   * The MySQL server or the server host was killed in the middle of an
     update.

   * You have found a bug in *Note `mysqld': mysqld. that caused it to
     die in the middle of an update.

   * Some external program is manipulating data files or index files at
     the same time as *Note `mysqld': mysqld.  without locking the
     table properly.

   * You are running many *Note `mysqld': mysqld. servers using the
     same data directory on a system that doesn't support good file
     system locks (normally handled by the `lockd' lock manager), or
     you are running multiple servers with external locking disabled.

   * You have a crashed data file or index file that contains very
     corrupt data that confused *Note `mysqld': mysqld.

   * You have found a bug in the data storage code. This isn't likely,
     but it is at least possible. In this case, you can try to change
     the storage engine to another engine by using *Note `ALTER TABLE':
     alter-table. on a repaired copy of the table.

Because it is very difficult to know why something is crashing, first
try to check whether things that work for others crash for you. Please
try the following things:

   * Stop the *Note `mysqld': mysqld. server with *Note `mysqladmin
     shutdown': mysqladmin, run *Note `myisamchk --silent --force
     */*.MYI': myisamchk. from the data directory to check all `MyISAM'
     tables, and restart *Note `mysqld': mysqld. This ensures that you
     are running from a clean state. See *Note server-administration::.

   * Start *Note `mysqld': mysqld. with the general query log enabled
     (see *Note query-log::). Then try to determine from the
     information written to the log whether some specific query kills
     the server. About 95% of all bugs are related to a particular
     query. Normally, this is one of the last queries in the log file
     just before the server restarts. See *Note query-log::. If you can
     repeatedly kill MySQL with a specific query, even when you have
     checked all tables just before issuing it, then you have been able
     to locate the bug and should submit a bug report for it. See *Note
     bug-reports::.

   * Try to make a test case that we can use to repeat the problem. See
     MySQL Internals: Porting
     (http://forge.mysql.com/wiki/MySQL_Internals_Porting).

   * Try running the tests in the `mysql-test' directory and the MySQL
     benchmarks. See *Note mysql-test-suite::. They should test MySQL
     rather well. You can also add code to the benchmarks that
     simulates your application. The benchmarks can be found in the
     `sql-bench' directory in a source distribution or, for a binary
     distribution, in the `sql-bench' directory under your MySQL
     installation directory.

   * Try the `fork_big.pl' script. (It is located in the `tests'
     directory of source distributions.)

   * If you configure MySQL for debugging, it is much easier to gather
     information about possible errors if something goes wrong.
     Configuring MySQL for debugging causes a safe memory allocator to
     be included that can find some errors.  It also provides a lot of
     output about what is happening.  Reconfigure MySQL with the
     `--with-debug' or `--with-debug=full' option to `configure' and
     then recompile. See MySQL Internals: Porting
     (http://forge.mysql.com/wiki/MySQL_Internals_Porting).

   * Make sure that you have applied the latest patches for your
     operating system.

   * Use the `--skip-external-locking' option to *Note `mysqld':
     mysqld. On some systems, the `lockd' lock manager does not work
     properly; the `--skip-external-locking' option tells *Note
     `mysqld': mysqld. not to use external locking. (This means that
     you cannot run two *Note `mysqld': mysqld. servers on the same data
     directory and that you must be careful if you use *Note
     `myisamchk': myisamchk. Nevertheless, it may be instructive to try
     the option as a test.)

   * Have you tried *Note `mysqladmin -u root processlist': mysqladmin.
     when *Note `mysqld': mysqld.  appears to be running but not
     responding? Sometimes *Note `mysqld': mysqld. is not comatose even
     though you might think so. The problem may be that all connections
     are in use, or there may be some internal lock problem.  *Note
     `mysqladmin -u root processlist': mysqladmin. usually is able to
     make a connection even in these cases, and can provide useful
     information about the current number of connections and their
     status.

   * Run the command *Note `mysqladmin -i 5 status': mysqladmin.  or
     *Note `mysqladmin -i 5 -r status': mysqladmin. in a separate
     window to produce statistics while you run your other queries.

   * Try the following:

       1. Start *Note `mysqld': mysqld. from `gdb' (or another
          debugger). See MySQL Internals: Porting
          (http://forge.mysql.com/wiki/MySQL_Internals_Porting).

       2. Run your test scripts.

       3. Print the backtrace and the local variables at the three
          lowest levels. In `gdb', you can do this with the following
          commands when *Note `mysqld': mysqld. has crashed inside
          `gdb':

               backtrace
               info local
               up
               info local
               up
               info local

          With `gdb', you can also examine which threads exist with
          `info threads' and switch to a specific thread with `thread
          N', where N is the thread ID.

   * Try to simulate your application with a Perl script to force MySQL
     to crash or misbehave.

   * Send a normal bug report. See *Note bug-reports::. Be even more
     detailed than usual. Because MySQL works for many people, it may
     be that the crash results from something that exists only on your
     computer (for example, an error that is related to your particular
     system libraries).

   * If you have a problem with tables containing dynamic-length rows
     and you are using only *Note `VARCHAR': char. columns (not *Note
     `BLOB': blob. or *Note `TEXT': blob. columns), you can try to
     change all *Note `VARCHAR': char. to *Note `CHAR': char. with
     *Note `ALTER TABLE': alter-table. This forces MySQL to use
     fixed-size rows. Fixed-size rows take a little extra space, but
     are much more tolerant to corruption.

     The current dynamic row code has been in use for several years
     with very few problems, but dynamic-length rows are by nature more
     prone to errors, so it may be a good idea to try this strategy to
     see whether it helps.

   * Do not rule out your server hardware when diagnosing problems.
     Defective hardware can be the cause of data corruption. Particular
     attention should be paid to your memory and disk subsystems when
     troubleshooting hardware.


File: manual.info,  Node: full-disk,  Next: temporary-files,  Prev: crashing,  Up: administration-issues

C.5.4.6 How MySQL Handles a Full Disk
.....................................

This section describes how MySQL responds to disk-full errors (such as
`no space left on device'), and to quota-exceeded errors (such as
`write failed' or `user block limit reached').

This section is relevant for writes to `MyISAM' tables. It also applies
for writes to binary log files and binary log index file, except that
references to `row' and `record' should be understood to mean `event.'

When a disk-full condition occurs, MySQL does the following:

   * It checks once every minute to see whether there is enough space
     to write the current row. If there is enough space, it continues
     as if nothing had happened.

   * Every 10 minutes it writes an entry to the log file, warning about
     the disk-full condition.

To alleviate the problem, you can take the following actions:

   * To continue, you only have to free enough disk space to insert all
     records.

   * To abort the thread, you must use *Note `mysqladmin kill':
     mysqladmin. The thread is aborted the next time it checks the disk
     (in one minute).

   * Other threads might be waiting for the table that caused the
     disk-full condition. If you have several `locked' threads, killing
     the one thread that is waiting on the disk-full condition enables
     the other threads to continue.

Exceptions to the preceding behavior are when you use *Note `REPAIR
TABLE': repair-table. or *Note `OPTIMIZE TABLE': optimize-table. or
when the indexes are created in a batch after *Note `LOAD DATA INFILE':
load-data. or after an *Note `ALTER TABLE': alter-table. statement. All
of these statements may create large temporary files that, if left to
themselves, would cause big problems for the rest of the system. If the
disk becomes full while MySQL is doing any of these operations, it
removes the big temporary files and mark the table as crashed. The
exception is that for *Note `ALTER TABLE': alter-table, the old table
is left unchanged.


File: manual.info,  Node: temporary-files,  Next: problems-with-mysql-sock,  Prev: full-disk,  Up: administration-issues

C.5.4.7 Where MySQL Stores Temporary Files
..........................................

On Unix, MySQL uses the value of the `TMPDIR' environment variable as
the path name of the directory in which to store temporary files. If
`TMPDIR' is not set, MySQL uses the system default, which is usually
`/tmp', `/var/tmp', or `/usr/tmp'.

On Windows, Netware and OS2, MySQL checks in order the values of the
`TMPDIR', `TEMP', and `TMP' environment variables. For the first one
found to be set, MySQL uses it and does not check those remaining. If
none of `TMPDIR', `TEMP', or `TMP' are set, MySQL uses the Windows
system default, which is usually `C:\windows\temp\'.

If the file system containing your temporary file directory is too
small, you can use the `--tmpdir' option to *Note `mysqld': mysqld. to
specify a directory in a file system where you have enough space.

In MySQL 5.0, the `--tmpdir' option can be set to a list of several
paths that are used in round-robin fashion.  Paths should be separated
by colon characters (``:'') on Unix and semicolon characters (``;'') on
Windows, NetWare, and OS/2.

*Note*:

To spread the load effectively, these paths should be located on
different _physical_ disks, not different partitions of the same disk.

If the MySQL server is acting as a replication slave, you should not
set `--tmpdir' to point to a directory on a memory-based file system or
to a directory that is cleared when the server host restarts. A
replication slave needs some of its temporary files to survive a
machine restart so that it can replicate temporary tables or *Note
`LOAD DATA INFILE': load-data. operations. If files in the temporary
file directory are lost when the server restarts, replication fails.

MySQL creates all temporary files as hidden files. This ensures that
the temporary files are removed if *Note `mysqld': mysqld. is
terminated. The disadvantage of using hidden files is that you do not
see a big temporary file that fills up the file system in which the
temporary file directory is located.

When sorting (`ORDER BY' or `GROUP BY'), MySQL normally uses one or two
temporary files.  The maximum disk space required is determined by the
following expression:

     (length of what is sorted + sizeof(row pointer))
     * number of matched rows
     * 2

The row pointer size is usually four bytes, but may grow in the future
for really big tables.

For some *Note `SELECT': select. queries, MySQL also creates temporary
SQL tables. These are not hidden and have names of the form `SQL_*'.

*Note `ALTER TABLE': alter-table. creates a temporary table in the same
directory as the original table.


File: manual.info,  Node: problems-with-mysql-sock,  Next: timezone-problems,  Prev: temporary-files,  Up: administration-issues

C.5.4.8 How to Protect or Change the MySQL Unix Socket File
...........................................................

The default location for the Unix socket file that the server uses for
communication with local clients is `/tmp/mysql.sock'. (For some
distribution formats, the directory might be different, such as
`/var/lib/mysql' for RPMs.)

On some versions of Unix, anyone can delete files in the `/tmp'
directory or other similar directories used for temporary files. If the
socket file is located in such a directory on your system, this might
cause problems.

On most versions of Unix, you can protect your `/tmp' directory so that
files can be deleted only by their owners or the superuser (`root'). To
do this, set the `sticky' bit on the `/tmp' directory by logging in as
`root' and using the following command:

     shell> chmod +t /tmp

You can check whether the `sticky' bit is set by executing `ls -ld
/tmp'. If the last permission character is `t', the bit is set.

Another approach is to change the place where the server creates the
Unix socket file. If you do this, you should also let client programs
know the new location of the file. You can specify the file location in
several ways:

   * Specify the path in a global or local option file. For example,
     put the following lines in `/etc/my.cnf':

          [mysqld]
          socket=/path/to/socket

          [client]
          socket=/path/to/socket

     See *Note option-files::.

   * Specify a `--socket' option on the command line to *Note
     `mysqld_safe': mysqld-safe. and when you run client programs.

   * Set the `MYSQL_UNIX_PORT' environment variable to the path of the
     Unix socket file.

   * Recompile MySQL from source to use a different default Unix socket
     file location. Define the path to the file with the
     `--with-unix-socket-path' option when you run `configure'. See
     *Note source-configuration-options::.

You can test whether the new socket location works by attempting to
connect to the server with this command:

     shell> mysqladmin --socket=/path/to/socket version


File: manual.info,  Node: timezone-problems,  Prev: problems-with-mysql-sock,  Up: administration-issues

C.5.4.9 Time Zone Problems
..........................

If you have a problem with `SELECT NOW()' returning values in UTC and
not your local time, you have to tell the server your current time
zone. The same applies if `UNIX_TIMESTAMP()' returns the wrong value.
This should be done for the environment in which the server runs; for
example, in *Note `mysqld_safe': mysqld-safe. or *Note `mysql.server':
mysql-server. See *Note environment-variables::.

You can set the time zone for the server with the
`--timezone=TIMEZONE_NAME' option to *Note `mysqld_safe': mysqld-safe.
You can also set it by setting the `TZ' environment variable before you
start *Note `mysqld': mysqld.

The permissible values for `--timezone' or `TZ' are system dependent.
Consult your operating system documentation to see what values are
acceptable.


File: manual.info,  Node: query-issues,  Next: optimizer-issues,  Prev: administration-issues,  Up: problems

C.5.5 Query-Related Issues
--------------------------

* Menu:

* case-sensitivity::             Case Sensitivity in String Searches
* using-date::                   Problems Using `DATE' Columns
* problems-with-null::           Problems with `NULL' Values
* problems-with-alias::          Problems with Column Aliases
* non-transactional-tables::     Rollback Failure for Nontransactional Tables
* deleting-from-related-tables::  Deleting Rows from Related Tables
* no-matching-rows::             Solving Problems with No Matching Rows
* problems-with-float::          Problems with Floating-Point Values


File: manual.info,  Node: case-sensitivity,  Next: using-date,  Prev: query-issues,  Up: query-issues

C.5.5.1 Case Sensitivity in String Searches
...........................................

For nonbinary strings (*Note `CHAR': char, *Note `VARCHAR': char, *Note
`TEXT': blob.), string searches use the collation of the comparison
operands. For binary strings (*Note `BINARY': binary-varbinary, *Note
`VARBINARY': binary-varbinary, *Note `BLOB': blob.), comparisons use the
numeric values of the bytes in the operands; this means that for
alphabetic characters, comparisons will be case sensitive.

A comparison between a nonbinary string and binary string is treated as
a comparison of binary strings.

Simple comparison operations (`>=, >, =, <, <=', sorting, and grouping)
are based on each character's `sort value.' Characters with the same
sort value are treated as the same character. For example, if ``e'' and
``e''' have the same sort value in a given collation, they compare as
equal.

The default character set and collation are `latin1' and
`latin1_swedish_ci', so nonbinary string comparisons are case
insensitive by default. This means that if you search with `COL_NAME
LIKE 'a%'', you get all column values that start with `A' or `a'. To
make this search case sensitive, make sure that one of the operands has
a case sensitive or binary collation. For example, if you are comparing
a column and a string that both have the `latin1' character set, you
can use the `COLLATE' operator to cause either operand to have the
`latin1_general_cs' or `latin1_bin' collation:

     COL_NAME COLLATE latin1_general_cs LIKE 'a%'
     COL_NAME LIKE 'a%' COLLATE latin1_general_cs
     COL_NAME COLLATE latin1_bin LIKE 'a%'
     COL_NAME LIKE 'a%' COLLATE latin1_bin

If you want a column always to be treated in case-sensitive fashion,
declare it with a case sensitive or binary collation.  See *Note
create-table::.

To cause a case-sensitive comparison of nonbinary strings to be case
insensitive, use `COLLATE' to name a case-insensitive collation. The
strings in the following example normally are case sensitive, but
`COLLATE' changes the comparison to be case insensitive:

     mysql> SET @s1 = 'MySQL' COLLATE latin1_bin,
         ->     @s2 = 'mysql' COLLATE latin1_bin;
     mysql> SELECT @s1 = @s2;
     +-----------+
     | @s1 = @s2 |
     +-----------+
     |         0 |
     +-----------+
     mysql> SELECT @s1 COLLATE latin1_swedish_ci = @s2;
     +-------------------------------------+
     | @s1 COLLATE latin1_swedish_ci = @s2 |
     +-------------------------------------+
     |                                   1 |
     +-------------------------------------+

A binary string is case sensitive in comparisons. To compare the string
as case insensitive, convert it to a nonbinary string and use `COLLATE'
to name a case-insensitive collation:

     mysql> SET @s = BINARY 'MySQL';
     mysql> SELECT @s = 'mysql';
     +--------------+
     | @s = 'mysql' |
     +--------------+
     |            0 |
     +--------------+
     mysql> SELECT CONVERT(@s USING latin1) COLLATE latin1_swedish_ci = 'mysql';
     +--------------------------------------------------------------+
     | CONVERT(@s USING latin1) COLLATE latin1_swedish_ci = 'mysql' |
     +--------------------------------------------------------------+
     |                                                            1 |
     +--------------------------------------------------------------+

To determine whether a value will compare as a nonbinary or binary
string, use the `COLLATION()' function. This example shows that
`VERSION()' returns a string that has a case-insensitive collation, so
comparisons are case insensitive:

     mysql> SELECT COLLATION(VERSION());
     +----------------------+
     | COLLATION(VERSION()) |
     +----------------------+
     | utf8_general_ci      |
     +----------------------+

For binary strings, the collation value is `binary', so comparisons
will be case sensitive. One context in which you will see `binary' is
for compression and encryption functions, which return binary strings
as a general rule: string:

     mysql> SELECT COLLATION(ENCRYPT('x')), COLLATION(SHA1('x'));
     +-------------------------+----------------------+
     | COLLATION(ENCRYPT('x')) | COLLATION(SHA1('x')) |
     +-------------------------+----------------------+
     | binary                  | binary               |
     +-------------------------+----------------------+


File: manual.info,  Node: using-date,  Next: problems-with-null,  Prev: case-sensitivity,  Up: query-issues

C.5.5.2 Problems Using `DATE' Columns
.....................................

The format of a *Note `DATE': datetime. value is `'YYYY-MM-DD''.
According to standard SQL, no other format is permitted. You should use
this format in *Note `UPDATE': update. expressions and in the `WHERE'
clause of *Note `SELECT': select. statements. For example:

     SELECT * FROM t1 WHERE date >= '2003-05-05';

As a convenience, MySQL automatically converts a date to a number if
the date is used in a numeric context and vice versa. MySQL also
permits a `relaxed' string format when updating and in a `WHERE' clause
that compares a date to a *Note `DATE': datetime, *Note `DATETIME':
datetime, or *Note `TIMESTAMP': datetime. column.  `Relaxed' format
means that any punctuation character may be used as the separator
between parts. For example, `'2004-08-15'' and `'2004#08#15'' are
equivalent. MySQL can also convert a string containing no separators
(such as `'20040815''), provided it makes sense as a date.

When you compare a *Note `DATE': datetime, *Note `TIME': time, *Note
`DATETIME': datetime, or *Note `TIMESTAMP': datetime. to a constant
string with the `<', `<=', `=', `>=', `>', or `BETWEEN' operators,
MySQL normally converts the string to an internal long integer for
faster comparison (and also for a bit more `relaxed' string checking).
However, this conversion is subject to the following exceptions:

   * When you compare two columns

   * When you compare a *Note `DATE': datetime, *Note `TIME': time,
     *Note `DATETIME': datetime, or *Note `TIMESTAMP': datetime. column
     to an expression

   * When you use any comparison method other than those just listed,
     such as `IN' or `STRCMP()'.

For those exceptions, the comparison is done by converting the objects
to strings and performing a string comparison.

To be on the safe side, assume that strings are compared as strings and
use the appropriate string functions if you want to compare a temporal
value to a string.

The special `zero' date `'0000-00-00'' can be stored and retrieved as
`'0000-00-00'.' When a `'0000-00-00'' date is used through
Connector/ODBC, it is automatically converted to `NULL' because ODBC
cannot handle that kind of date.

Because MySQL performs the conversions just described, the following
statements work (assume that `idate' is a *Note `DATE': datetime.
column):

     INSERT INTO t1 (idate) VALUES (19970505);
     INSERT INTO t1 (idate) VALUES ('19970505');
     INSERT INTO t1 (idate) VALUES ('97-05-05');
     INSERT INTO t1 (idate) VALUES ('1997.05.05');
     INSERT INTO t1 (idate) VALUES ('1997 05 05');
     INSERT INTO t1 (idate) VALUES ('0000-00-00');

     SELECT idate FROM t1 WHERE idate >= '1997-05-05';
     SELECT idate FROM t1 WHERE idate >= 19970505;
     SELECT MOD(idate,100) FROM t1 WHERE idate >= 19970505;
     SELECT idate FROM t1 WHERE idate >= '19970505';

However, the following statement does not work:

     SELECT idate FROM t1 WHERE STRCMP(idate,'20030505')=0;

`STRCMP()' is a string function, so it converts `idate' to a string in
`'YYYY-MM-DD'' format and performs a string comparison. It does not
convert `'20030505'' to the date `'2003-05-05'' and perform a date
comparison.

If you enable the `ALLOW_INVALID_DATES' SQL mode, MySQL permits you to
store dates that are given only limited checking: MySQL requires only
that the day is in the range from 1 to 31 and the month is in the range
from 1 to 12.  This makes MySQL very convenient for Web applications
where you obtain year, month, and day in three different fields and you
want to store exactly what the user inserted (without date validation).

MySQL permits you to store dates where the day or month and day are
zero. This is convenient if you want to store a birthdate in a *Note
`DATE': datetime. column and you know only part of the date. To
disallow zero month or day parts in dates, enable the `NO_ZERO_IN_DATE'
SQL mode.

MySQL permits you to store a `zero' value of `'0000-00-00'' as a `dummy
date.' This is in some cases more convenient than using `NULL' values.
If a date to be stored in a *Note `DATE': datetime. column cannot be
converted to any reasonable value, MySQL stores `'0000-00-00''. To
disallow `'0000-00-00'', enable the `NO_ZERO_DATE' SQL mode.

To have MySQL check all dates and accept only legal dates (unless
overridden by `IGNORE'), set the `sql_mode' system variable to
`"NO_ZERO_IN_DATE,NO_ZERO_DATE"'.

Date handling in MySQL 5.0.1 and earlier works like MySQL 5.0.2 with the
`ALLOW_INVALID_DATES' SQL mode enabled.


File: manual.info,  Node: problems-with-null,  Next: problems-with-alias,  Prev: using-date,  Up: query-issues

C.5.5.3 Problems with `NULL' Values
...................................

The concept of the `NULL' value is a common source of confusion for
newcomers to SQL, who often think that `NULL' is the same thing as an
empty string `'''. This is not the case. For example, the following
statements are completely different:

     mysql> INSERT INTO my_table (phone) VALUES (NULL);
     mysql> INSERT INTO my_table (phone) VALUES ('');

Both statements insert a value into the `phone' column, but the first
inserts a `NULL' value and the second inserts an empty string. The
meaning of the first can be regarded as `phone number is not known' and
the meaning of the second can be regarded as `the person is known to
have no phone, and thus no phone number.'

To help with `NULL' handling, you can use the `IS NULL' and `IS NOT
NULL' operators and the `IFNULL()' function.

In SQL, the `NULL' value is never true in comparison to any other
value, even `NULL'.  An expression that contains `NULL' always produces
a `NULL' value unless otherwise indicated in the documentation for the
operators and functions involved in the expression. All columns in the
following example return `NULL':

     mysql> SELECT NULL, 1+NULL, CONCAT('Invisible',NULL);

To search for column values that are `NULL', you cannot use an `expr =
NULL' test. The following statement returns no rows, because `expr =
NULL' is never true for any expression:

     mysql> SELECT * FROM my_table WHERE phone = NULL;

To look for `NULL' values, you must use the `IS NULL' test. The
following statements show how to find the `NULL' phone number and the
empty phone number:

     mysql> SELECT * FROM my_table WHERE phone IS NULL;
     mysql> SELECT * FROM my_table WHERE phone = '';

See *Note working-with-null::, for additional information and examples.

You can add an index on a column that can have `NULL' values if you are
using the `MyISAM', `InnoDB', or `BDB', or `MEMORY' storage engine.
Otherwise, you must declare an indexed column `NOT NULL', and you
cannot insert `NULL' into the column.

When reading data with *Note `LOAD DATA INFILE': load-data, empty or
missing columns are updated with `'''. To load a `NULL' value into a
column, use `\N' in the data file. The literal word ``NULL'' may also
be used under some circumstances. See *Note load-data::.

When using `DISTINCT', `GROUP BY', or `ORDER BY', all `NULL' values are
regarded as equal.

When using `ORDER BY', `NULL' values are presented first, or last if
you specify `DESC' to sort in descending order.

Aggregate (summary) functions such as `COUNT()', `MIN()', and `SUM()'
ignore `NULL' values. The exception to this is `COUNT(*)', which counts
rows and not individual column values. For example, the following
statement produces two counts. The first is a count of the number of
rows in the table, and the second is a count of the number of
non-`NULL' values in the `age' column:

     mysql> SELECT COUNT(*), COUNT(age) FROM person;

For some data types, MySQL handles `NULL' values specially. If you
insert `NULL' into a *Note `TIMESTAMP': datetime. column, the current
date and time is inserted. If you insert `NULL' into an integer or
floating-point column that has the `AUTO_INCREMENT' attribute, the next
number in the sequence is inserted.


File: manual.info,  Node: problems-with-alias,  Next: non-transactional-tables,  Prev: problems-with-null,  Up: query-issues

C.5.5.4 Problems with Column Aliases
....................................

An alias can be used in a query select list to give a column a
different name. You can use the alias in `GROUP BY', `ORDER BY', or
`HAVING' clauses to refer to the column:

     SELECT SQRT(a*b) AS root FROM TBL_NAME
       GROUP BY root HAVING root > 0;
     SELECT id, COUNT(*) AS cnt FROM TBL_NAME
       GROUP BY id HAVING cnt > 0;
     SELECT id AS 'Customer identity' FROM TBL_NAME;

Standard SQL disallows references to column aliases in a `WHERE'
clause. This restriction is imposed because when the `WHERE' clause is
evaluated, the column value may not yet have been determined. For
example, the following query is illegal:

     SELECT id, COUNT(*) AS cnt FROM TBL_NAME
       WHERE cnt > 0 GROUP BY id;

The `WHERE' clause determines which rows should be included in the
`GROUP BY' clause, but it refers to the alias of a column value that is
not known until after the rows have been selected, and grouped by the
`GROUP BY'.

In the select list of a query, a quoted column alias can be specified
using identifier or string quoting characters:

     SELECT 1 AS `one`, 2 AS 'two';

Elsewhere in the statement, quoted references to the alias must use
identifier quoting or the reference is treated as a string literal. For
example, this statement groups by the values in column `id', referenced
using the alias ``a`':

     SELECT id AS 'a', COUNT(*) AS cnt FROM TBL_NAME
       GROUP BY `a`;

But this statement groups by the literal string `'a'' and will not work
as expected:

     SELECT id AS 'a', COUNT(*) AS cnt FROM TBL_NAME
       GROUP BY 'a';


File: manual.info,  Node: non-transactional-tables,  Next: deleting-from-related-tables,  Prev: problems-with-alias,  Up: query-issues

C.5.5.5 Rollback Failure for Nontransactional Tables
....................................................

If you receive the following message when trying to perform a *Note
`ROLLBACK': commit, it means that one or more of the tables you used in
the transaction do not support transactions:

     Warning: Some non-transactional changed tables couldn't be rolled back

These nontransactional tables are not affected by the *Note `ROLLBACK':
commit.  statement.

If you were not deliberately mixing transactional and nontransactional
tables within the transaction, the most likely cause for this message
is that a table you thought was transactional actually is not. This can
happen if you try to create a table using a transactional storage
engine that is not supported by your *Note `mysqld': mysqld. server (or
that was disabled with a startup option). If *Note `mysqld': mysqld.
doesn't support a storage engine, it instead creates the table as a
`MyISAM' table, which is nontransactional.

You can check the storage engine for a table by using either of these
statements:

     SHOW TABLE STATUS LIKE 'TBL_NAME';
     SHOW CREATE TABLE TBL_NAME;

See *Note show-table-status::, and *Note show-create-table::.

You can check which storage engines your *Note `mysqld': mysqld. server
supports by using this statement:

     SHOW ENGINES;

You can also use the following statement, and check the value of the
variable that is associated with the storage engine in which you are
interested:

     SHOW VARIABLES LIKE 'have_%';

For example, to determine whether the `InnoDB' storage engine is
available, check the value of the `have_innodb' variable.

See *Note show-engines::, and *Note show-variables::.


File: manual.info,  Node: deleting-from-related-tables,  Next: no-matching-rows,  Prev: non-transactional-tables,  Up: query-issues

C.5.5.6 Deleting Rows from Related Tables
.........................................

If the total length of the *Note `DELETE': delete. statement for
`related_table' is more than 1MB (the default value of the
`max_allowed_packet' system variable), you should split it into smaller
parts and execute multiple *Note `DELETE': delete. statements. You
probably get the fastest *Note `DELETE': delete.  by specifying only
100 to 1,000 `related_column' values per statement if the
`related_column' is indexed. If the `related_column' isn't indexed, the
speed is independent of the number of arguments in the `IN' clause.


File: manual.info,  Node: no-matching-rows,  Next: problems-with-float,  Prev: deleting-from-related-tables,  Up: query-issues

C.5.5.7 Solving Problems with No Matching Rows
..............................................

If you have a complicated query that uses many tables but that doesn't
return any rows, you should use the following procedure to find out
what is wrong:

  1. Test the query with *Note `EXPLAIN': explain.  to check whether
     you can find something that is obviously wrong. See *Note
     explain::.

  2. Select only those columns that are used in the `WHERE' clause.

  3. Remove one table at a time from the query until it returns some
     rows. If the tables are large, it is a good idea to use `LIMIT 10'
     with the query.

  4. Issue a *Note `SELECT': select. for the column that should have
     matched a row against the table that was last removed from the
     query.

  5. If you are comparing *Note `FLOAT': numeric-types.  or *Note
     `DOUBLE': numeric-types. columns with numbers that have decimals,
     you can't use equality (`=') comparisons. This problem is common
     in most computer languages because not all floating-point values
     can be stored with exact precision. In some cases, changing the
     *Note `FLOAT': numeric-types. to a *Note `DOUBLE': numeric-types.
     fixes this. See *Note problems-with-float::.

     Similar problems may be encountered when comparing *Note
     `DECIMAL': numeric-types. values prior to MySQL 5.0.3.

  6. If you still can't figure out what is wrong, create a minimal test
     that can be run with `mysql test < query.sql' that shows your
     problems. You can create a test file by dumping the tables with
     *Note `mysqldump --quick db_name TBL_NAME_1 ... TBL_NAME_N >
     query.sql': mysqldump. Open the file in an editor, remove some
     insert lines (if there are more than needed to demonstrate the
     problem), and add your *Note `SELECT': select. statement at the end
     of the file.

     Verify that the test file demonstrates the problem by executing
     these commands:

          shell> mysqladmin create test2
          shell> mysql test2 < query.sql

     Attach the test file to a bug report, which you can file using the
     instructions in *Note bug-reports::.


File: manual.info,  Node: problems-with-float,  Prev: no-matching-rows,  Up: query-issues

C.5.5.8 Problems with Floating-Point Values
...........................................

Floating-point numbers sometimes cause confusion because they are
approximate and not stored as exact values. A floating-point value as
written in an SQL statement may not be the same as the value
represented internally. Attempts to treat floating-point values as
exact in comparisons may lead to problems. They are also subject to
platform or implementation dependencies. The *Note `FLOAT':
numeric-types. and *Note `DOUBLE': numeric-types. data types are subject
to these issues. Before MySQL 5.0.3, *Note `DECIMAL': numeric-types.
comparison operations are approximate as well.

Prior to MySQL 5.0.3, *Note `DECIMAL': numeric-types.  columns store
values with exact precision because they are represented as strings,
but calculations on *Note `DECIMAL': numeric-types. values are done
using floating-point operations. As of 5.0.6, MySQL performs *Note
`DECIMAL': numeric-types. operations with a precision of 65 decimal
digits (64 digits from 5.0.3 to 5.0.5), which should solve most common
inaccuracy problems when it comes to *Note `DECIMAL': numeric-types.
columns. (If your server is from MySQL 5.0.3 or higher, but you have
*Note `DECIMAL': numeric-types. columns in tables that were created
before 5.0.3, the old behavior still applies to those columns. To
convert the tables to the newer *Note `DECIMAL': numeric-types. format,
dump them with *Note `mysqldump': mysqldump. and reload them.)

The following example (for versions of MySQL older than 5.0.3)
demonstrates the problem. It shows that even for older *Note `DECIMAL':
numeric-types. columns, calculations that are done using floating-point
operations are subject to floating-point error. (Were you to replace the
*Note `DECIMAL': numeric-types. columns with *Note `FLOAT':
numeric-types, similar problems would occur for all versions of MySQL.)

     mysql> CREATE TABLE t1 (i INT, d1 DECIMAL(9,2), d2 DECIMAL(9,2));
     mysql> INSERT INTO t1 VALUES (1, 101.40, 21.40), (1, -80.00, 0.00),
         -> (2, 0.00, 0.00), (2, -13.20, 0.00), (2, 59.60, 46.40),
         -> (2, 30.40, 30.40), (3, 37.00, 7.40), (3, -29.60, 0.00),
         -> (4, 60.00, 15.40), (4, -10.60, 0.00), (4, -34.00, 0.00),
         -> (5, 33.00, 0.00), (5, -25.80, 0.00), (5, 0.00, 7.20),
         -> (6, 0.00, 0.00), (6, -51.40, 0.00);

     mysql> SELECT i, SUM(d1) AS a, SUM(d2) AS b
         -> FROM t1 GROUP BY i HAVING a <> b;
     +------+--------+-------+
     | i    | a      | b     |
     +------+--------+-------+
     |    1 |  21.40 | 21.40 |
     |    2 |  76.80 | 76.80 |
     |    3 |   7.40 |  7.40 |
     |    4 |  15.40 | 15.40 |
     |    5 |   7.20 |  7.20 |
     |    6 | -51.40 |  0.00 |
     +------+--------+-------+

The result is correct. Although the first five records look like they
should not satisfy the comparison (the values of `a' and `b' do not
appear to be different), they may do so because the difference between
the numbers shows up around the tenth decimal or so, depending on
factors such as computer architecture or the compiler version or
optimization level. For example, different CPUs may evaluate
floating-point numbers differently.

As of MySQL 5.0.3, you will get only the last row in the above result.

The problem cannot be solved by using `ROUND()' or similar functions,
because the result is still a floating-point number:

     mysql> SELECT i, ROUND(SUM(d1), 2) AS a, ROUND(SUM(d2), 2) AS b
         -> FROM t1 GROUP BY i HAVING a <> b;
     +------+--------+-------+
     | i    | a      | b     |
     +------+--------+-------+
     |    1 |  21.40 | 21.40 |
     |    2 |  76.80 | 76.80 |
     |    3 |   7.40 |  7.40 |
     |    4 |  15.40 | 15.40 |
     |    5 |   7.20 |  7.20 |
     |    6 | -51.40 |  0.00 |
     +------+--------+-------+

This is what the numbers in column `a' look like when displayed with
more decimal places:

     mysql> SELECT i, ROUND(SUM(d1), 2)*1.0000000000000000 AS a,
         -> ROUND(SUM(d2), 2) AS b FROM t1 GROUP BY i HAVING a <> b;
     +------+----------------------+-------+
     | i    | a                    | b     |
     +------+----------------------+-------+
     |    1 |  21.3999999999999986 | 21.40 |
     |    2 |  76.7999999999999972 | 76.80 |
     |    3 |   7.4000000000000004 |  7.40 |
     |    4 |  15.4000000000000004 | 15.40 |
     |    5 |   7.2000000000000002 |  7.20 |
     |    6 | -51.3999999999999986 |  0.00 |
     +------+----------------------+-------+

Depending on your computer architecture, you may or may not see similar
results. For example, on some machines you may get the `correct'
results by multiplying both arguments by 1, as the following example
shows.

*Warning*:

Never use this method in your applications. It is not an example of a
trustworthy method!

     mysql> SELECT i, ROUND(SUM(d1), 2)*1 AS a, ROUND(SUM(d2), 2)*1 AS b
         -> FROM t1 GROUP BY i HAVING a <> b;
     +------+--------+------+
     | i    | a      | b    |
     +------+--------+------+
     |    6 | -51.40 | 0.00 |
     +------+--------+------+

The reason that the preceding example seems to work is that on the
particular machine where the test was done, CPU floating-point
arithmetic happens to round the numbers to the same value. However,
there is no rule that any CPU should do so, so this method cannot be
trusted.

The correct way to do floating-point number comparison is to first
decide on an acceptable tolerance for differences between the numbers
and then do the comparison against the tolerance value. For example, if
we agree that floating-point numbers should be regarded the same if
they are same within a precision of one in ten thousand (0.0001), the
comparison should be written to find differences larger than the
tolerance value:

     mysql> SELECT i, SUM(d1) AS a, SUM(d2) AS b FROM t1
         -> GROUP BY i HAVING ABS(a - b) > 0.0001;
     +------+--------+------+
     | i    | a      | b    |
     +------+--------+------+
     |    6 | -51.40 | 0.00 |
     +------+--------+------+
     1 row in set (0.00 sec)

Conversely, to get rows where the numbers are the same, the test should
find differences within the tolerance value:

     mysql> SELECT i, SUM(d1) AS a, SUM(d2) AS b FROM t1
         -> GROUP BY i HAVING ABS(a - b) <= 0.0001;
     +------+-------+-------+
     | i    | a     | b     |
     +------+-------+-------+
     |    1 | 21.40 | 21.40 |
     |    2 | 76.80 | 76.80 |
     |    3 |  7.40 |  7.40 |
     |    4 | 15.40 | 15.40 |
     |    5 |  7.20 |  7.20 |
     +------+-------+-------+

Floating-point values are subject to platform or implementation
dependencies. Suppose that you execute the following statements:

     CREATE TABLE t1(c1 FLOAT(53,0), c2 FLOAT(53,0));
     INSERT INTO t1 VALUES('1e+52','-1e+52');
     SELECT * FROM t1;

On some platforms, the `SELECT' statement returns `inf' and `-inf'.
Other others, it returns `0' and `-0'.

An implication of the preceding issues is that if you attempt to create
a replication slave by dumping table contents with *Note `mysqldump':
mysqldump. on the master and reloading the dump file into the slave,
tables containing floating-point columns might differ between the two
hosts.


File: manual.info,  Node: optimizer-issues,  Next: table-definition-issues,  Prev: query-issues,  Up: problems

C.5.6 Optimizer-Related Issues
------------------------------

MySQL uses a cost-based optimizer to determine the best way to resolve
a query. In many cases, MySQL can calculate the best possible query
plan, but sometimes MySQL doesn't have enough information about the
data at hand and has to make `educated' guesses about the data.

For the cases when MySQL does not do the "right" thing, tools that you
have available to help MySQL are:

   * Use the *Note `EXPLAIN': explain. statement to get information
     about how MySQL processes a query. To use it, just add the keyword
     *Note `EXPLAIN': explain. to the front of your *Note `SELECT':
     select. statement:

          mysql> EXPLAIN SELECT * FROM t1, t2 WHERE t1.i = t2.i;

     *Note `EXPLAIN': explain. is discussed in more detail in *Note
     explain::.

   * Use `ANALYZE TABLE TBL_NAME' to update the key distributions for
     the scanned table. See *Note analyze-table::.

   * Use `FORCE INDEX' for the scanned table to tell MySQL that table
     scans are very expensive compared to using the given index:

          SELECT * FROM t1, t2 FORCE INDEX (index_for_column)
          WHERE t1.col_name=t2.col_name;

     `USE INDEX' and `IGNORE INDEX' may also be useful. See *Note
     index-hints::.

   * Global and table-level `STRAIGHT_JOIN'. See *Note select::.

   * You can tune global or thread-specific system variables. For
     example, Start *Note `mysqld': mysqld. with the
     `--max-seeks-for-key=1000' option or use `SET
     max_seeks_for_key=1000' to tell the optimizer to assume that no
     key scan causes more than 1,000 key seeks. See *Note
     server-system-variables::.


File: manual.info,  Node: table-definition-issues,  Next: bugs,  Prev: optimizer-issues,  Up: problems

C.5.7 Table Definition-Related Issues
-------------------------------------

* Menu:

* alter-table-problems::         Problems with `ALTER TABLE'
* temporary-table-problems::     `TEMPORARY' Table Problems


File: manual.info,  Node: alter-table-problems,  Next: temporary-table-problems,  Prev: table-definition-issues,  Up: table-definition-issues

C.5.7.1 Problems with `ALTER TABLE'
...................................

If you get a duplicate-key error when using *Note `ALTER TABLE':
alter-table. to change the character set or collation of a character
column, the cause is either that the new column collation maps two keys
to the same value or that the table is corrupted. In the latter case,
you should run *Note `REPAIR TABLE': repair-table. on the table.

If *Note `ALTER TABLE': alter-table. dies with the following error, the
problem may be that MySQL crashed during an earlier *Note `ALTER
TABLE': alter-table.  operation and there is an old table named `A-XXX'
or `B-XXX' lying around:

     Error on rename of './database/name.frm'
     to './database/B-XXX.frm' (Errcode: 17)

In this case, go to the MySQL data directory and delete all files that
have names starting with `A-' or `B-'. (You may want to move them
elsewhere instead of deleting them.)

*Note `ALTER TABLE': alter-table. works in the following way:

   * Create a new table named `A-XXX' with the requested structural
     changes.

   * Copy all rows from the original table to `A-XXX'.

   * Rename the original table to `B-XXX'.

   * Rename `A-XXX' to your original table name.

   * Delete `B-XXX'.

If something goes wrong with the renaming operation, MySQL tries to
undo the changes. If something goes seriously wrong (although this
shouldn't happen), MySQL may leave the old table as `B-XXX'. A simple
rename of the table files at the system level should get your data back.

If you use *Note `ALTER TABLE': alter-table. on a transactional table
or if you are using Windows or OS/2, *Note `ALTER TABLE': alter-table.
unlocks the table if you had done a *Note `LOCK TABLE': lock-tables. on
it. This is done because `InnoDB' and these operating systems cannot
drop a table that is in use.


File: manual.info,  Node: temporary-table-problems,  Prev: alter-table-problems,  Up: table-definition-issues

C.5.7.2 `TEMPORARY' Table Problems
..................................

The following list indicates limitations on the use of `TEMPORARY'
tables:

   * A `TEMPORARY' table can only be of type `MEMORY', `MyISAM',
     `MERGE', or `InnoDB'.

     Temporary tables are not supported for MySQL Cluster.

   * You cannot refer to a `TEMPORARY' table more than once in the same
     query. For example, the following does not work:

          mysql> SELECT * FROM temp_table, temp_table AS t2;
          ERROR 1137: Can't reopen table: 'temp_table'

     This error also occurs if you refer to a temporary table multiple
     times in a stored function under different aliases, even if the
     references occur in different statements within the function.

   * The *Note `SHOW TABLES': show-tables. statement does not list
     `TEMPORARY' tables.

   * You cannot use `RENAME' to rename a `TEMPORARY' table. However,
     you can use *Note `ALTER TABLE': alter-table. instead:

          mysql> ALTER TABLE orig_name RENAME new_name;

   * There are known issues in using temporary tables with replication.
     See *Note replication-features::, for more information.


File: manual.info,  Node: bugs,  Prev: table-definition-issues,  Up: problems

C.5.8 Known Issues in MySQL
---------------------------

This section lists known issues in recent versions of MySQL.

For information about platform-specific issues, see the installation
and porting instructions in *Note operating-system-specific-notes::, and
MySQL Internals: Porting
(http://forge.mysql.com/wiki/MySQL_Internals_Porting).

The following problems are known:

   * Subquery optimization for `IN' is not as effective as for `='.

   * Even if you use `lower_case_table_names=2' (which enables MySQL to
     remember the case used for databases and table names), MySQL does
     not remember the case used for database names for the function
     `DATABASE()' or within the various logs (on case-insensitive
     systems).

   * Dropping a `FOREIGN KEY' constraint doesn't work in replication
     because the constraint may have another name on the slave.

   * *Note `REPLACE': replace. (and *Note `LOAD DATA': load-data. with
     the *Note `REPLACE': replace. option) does not trigger `ON DELETE
     CASCADE'.

   * `DISTINCT' with `ORDER BY' doesn't work inside `GROUP_CONCAT()' if
     you don't use all and only those columns that are in the
     `DISTINCT' list.

   * If one user has a long-running transaction and another user drops
     a table that is updated in the transaction, there is small chance
     that the binary log may contain the *Note `DROP TABLE':
     drop-table. statement before the table is used in the transaction
     itself. We plan to fix this by having the *Note `DROP TABLE':
     drop-table.  statement wait until the table is not being used in
     any transaction.

   * When inserting a big integer value (between 2^63 and 2^64-1) into
     a decimal or string column, it is inserted as a negative value
     because the number is evaluated in a signed integer context.

   * *Note `FLUSH TABLES WITH READ LOCK': flush. does not block *Note
     `COMMIT': commit. if the server is running without binary logging,
     which may cause a problem (of consistency between tables) when
     doing a full backup.

   * *Note `ANALYZE TABLE': analyze-table. on a `BDB' table may in some
     cases make the table unusable until you restart *Note `mysqld':
     mysqld.  If this happens, look for errors of the following form in
     the MySQL error file:

          001207 22:07:56  bdb:  log_flush: LSN past current end-of-log

   * Don't execute *Note `ALTER TABLE': alter-table. on a `BDB' table
     on which you are running multiple-statement transactions until all
     those transactions complete. (The transaction might be ignored.)

   * *Note `ANALYZE TABLE': analyze-table, *Note `OPTIMIZE TABLE':
     optimize-table, and *Note `REPAIR TABLE': repair-table. may cause
     problems on tables for which you are using *Note `INSERT DELAYED':
     insert-delayed.

   * Performing `LOCK TABLE ...' and `FLUSH TABLES ...' doesn't
     guarantee that there isn't a half-finished transaction in progress
     on the table.

   * `BDB' tables are relatively slow to open.  If you have many `BDB'
     tables in a database, it takes a long time to use the *Note
     `mysql': mysql. client on the database if you are not using the
     `-A' option or if you are using `rehash'. This is especially
     noticeable when you have a large table cache.

   * Replication uses query-level logging: The master writes the
     executed queries to the binary log. This is a very fast, compact,
     and efficient logging method that works perfectly in most cases.

     It is possible for the data on the master and slave to become
     different if a query is designed in such a way that the data
     modification is nondeterministic (generally not a recommended
     practice, even outside of replication).

     For example:

        * *Note `CREATE TABLE ... SELECT': create-table-select. or
          *Note `INSERT ... SELECT': insert-select. statements that
          insert zero or `NULL' values into an `AUTO_INCREMENT' column.

        * *Note `DELETE': delete. if you are deleting rows from a table
          that has foreign keys with `ON DELETE CASCADE' properties.

        * *Note `REPLACE ... SELECT': replace, `INSERT IGNORE ...
          SELECT' if you have duplicate key values in the inserted data.

     *If and only if the preceding queries have no `ORDER BY' clause
     guaranteeing a deterministic order*.

     For example, for *Note `INSERT ... SELECT': insert-select. with no
     `ORDER BY', the *Note `SELECT': select. may return rows in a
     different order (which results in a row having different ranks,
     hence getting a different number in the `AUTO_INCREMENT' column),
     depending on the choices made by the optimizers on the master and
     slave.

     A query is optimized differently on the master and slave only if:

        * The table is stored using a different storage engine on the
          master than on the slave. (It is possible to use different
          storage engines on the master and slave. For example, you can
          use `InnoDB' on the master, but `MyISAM' on the slave if the
          slave has less available disk space.)

        * MySQL buffer sizes (`key_buffer_size', and so on) are
          different on the master and slave.

        * The master and slave run different MySQL versions, and the
          optimizer code differs between these versions.

     This problem may also affect database restoration using
     `mysqlbinlog|mysql'.

     The easiest way to avoid this problem is to add an `ORDER BY'
     clause to the aforementioned nondeterministic queries to ensure
     that the rows are always stored or modified in the same order.

The following issues are known and will be fixed in due time:

   * Log file names are based on the server host name (if you don't
     specify a file name with the startup option). You have to use
     options such as `--log-bin=OLD_HOST_NAME-bin' if you change your
     host name to something else. Another option is to rename the old
     files to reflect your host name change (if these are binary logs,
     you need to edit the binary log index file and fix the binary log
     file names there as well). See *Note server-options::.

   * *Note `mysqlbinlog': mysqlbinlog. does not delete temporary files
     left after a *Note `LOAD DATA INFILE': load-data. statement. See
     *Note mysqlbinlog::.

   * `RENAME' doesn't work with `TEMPORARY' tables or tables used in a
     `MERGE' table.

   * Due to the way table format (`.frm') files are stored, you cannot
     use character 255 (`CHAR(255)') in table names, column names, or
     enumerations. This is scheduled to be fixed in version 5.1 when we
     implement new table definition format files.

   * When using `SET CHARACTER SET', you can't use translated
     characters in database, table, and column names.

   * You can't use ``_'' or ``%'' with `ESCAPE' in `LIKE ...  ESCAPE'.

   * *Note `BLOB': blob. and *Note `TEXT': blob. values can't reliably
     be used in `GROUP BY', `ORDER BY' or `DISTINCT'. Only the first
     `max_sort_length' bytes are used when comparing *Note `BLOB': blob.
     values in these cases. The default value of `max_sort_length' is
     1024 and can be changed at server startup time or at runtime.

   * Numeric calculations are done with *Note `BIGINT': numeric-types.
     or *Note `DOUBLE': numeric-types. (both are normally 64 bits
     long). Which precision you get depends on the function.  The
     general rule is that bit functions are performed with *Note
     `BIGINT': numeric-types. precision, `IF()' and `ELT()' with *Note
     `BIGINT': numeric-types. or *Note `DOUBLE': numeric-types.
     precision, and the rest with *Note `DOUBLE': numeric-types.
     precision.  You should try to avoid using unsigned long long
     values if they resolve to be larger than 63 bits
     (9223372036854775807) for anything other than bit fields.

   * You can have up to 255 *Note `ENUM': enum.  and *Note `SET': set.
     columns in one table.

   * In `MIN()', `MAX()', and other aggregate functions, MySQL
     currently compares *Note `ENUM': enum. and *Note `SET': set.
     columns by their string value rather than by the string's relative
     position in the set.

   * *Note `mysqld_safe': mysqld-safe. redirects all messages from
     *Note `mysqld': mysqld. to the *Note `mysqld': mysqld.  log. One
     problem with this is that if you execute *Note `mysqladmin
     refresh': mysqladmin. to close and reopen the log, `stdout' and
     `stderr' are still redirected to the old log. If you use the
     general query log extensively, you should edit *Note
     `mysqld_safe': mysqld-safe. to log to `HOST_NAME.err' instead of
     `HOST_NAME.log' so that you can easily reclaim the space for the
     old log by deleting it and executing *Note `mysqladmin refresh':
     mysqladmin.

   * In an *Note `UPDATE': update. statement, columns are updated from
     left to right. If you refer to an updated column, you get the
     updated value instead of the original value. For example, the
     following statement increments `KEY' by `2', *not* `1':

          mysql> UPDATE TBL_NAME SET KEY=KEY+1,KEY=KEY+1;

   * You can refer to multiple temporary tables in the same query, but
     you cannot refer to any given temporary table more than once. For
     example, the following doesn't work:

          mysql> SELECT * FROM temp_table, temp_table AS t2;
          ERROR 1137: Can't reopen table: 'temp_table'

   * The optimizer may handle `DISTINCT' differently when you are using
     `hidden' columns in a join than when you are not. In a join,
     hidden columns are counted as part of the result (even if they are
     not shown), whereas in normal queries, hidden columns don't
     participate in the `DISTINCT' comparison.  We will probably change
     this in the future to never compare the hidden columns when
     executing `DISTINCT'.

     An example of this is:

          SELECT DISTINCT mp3id FROM band_downloads
                 WHERE userid = 9 ORDER BY id DESC;

     and

          SELECT DISTINCT band_downloads.mp3id
                 FROM band_downloads,band_mp3
                 WHERE band_downloads.userid = 9
                 AND band_mp3.id = band_downloads.mp3id
                 ORDER BY band_downloads.id DESC;

     In the second case, using MySQL Server 3.23.x, you may get two
     identical rows in the result set (because the values in the hidden
     `id' column may differ).

     Note that this happens only for queries where that do not have the
     `ORDER BY' columns in the result.

   * If you execute a `PROCEDURE' on a query that returns an empty set,
     in some cases the `PROCEDURE' does not transform the columns.

   * Creation of a table of type `MERGE' doesn't check whether the
     underlying tables are compatible types.

   * If you use *Note `ALTER TABLE': alter-table. to add a `UNIQUE'
     index to a table used in a `MERGE' table and then add a normal
     index on the `MERGE' table, the key order is different for the
     tables if there was an old, non-`UNIQUE' key in the table. This is
     because *Note `ALTER TABLE': alter-table. puts `UNIQUE' indexes
     before normal indexes to be able to detect duplicate keys as early
     as possible.


File: manual.info,  Node: news,  Next: restrictions,  Prev: error-handling,  Up: Top

Appendix D MySQL Change History
*******************************

* Menu:

* news-5-0-x::                   Changes in Release 5.0.x (Production)
* mysql-cluster-change-history::  Changes in MySQL Cluster
* connector-odbc-news::          MySQL Connector/ODBC (MyODBC) Change History
* connector-net-news::           MySQL Connector/Net Change History
* vstudio-plugin-news::          MySQL Visual Studio Plugin Change History
* cj-news::                      MySQL Connector/J Change History
* news-connector-mxj::           MySQL Connector/MXJ Change History
* mysql-proxy-news::             MySQL Proxy Change History

This appendix lists the changes from version to version in the MySQL
source code through the latest version of MySQL 5.0, which is currently
MySQL 5.0.95. We offer a version of the Manual for each series of MySQL
releases (5.0, 5.1, and so forth). For information about changes in
another release series of the MySQL database software, see the
corresponding version of this Manual.

End of Product Lifecycle

Active development for MySQL Database Server version 5.0 has ended.
Oracle offers various support offerings which may be of interest. For
details and more information, see the MySQL section of the Lifetime
Support Policy for Oracle Technology Products
(http://www.oracle.com/us/support/lifetime-support/index.html). Please
consider upgrading to a recent version.

We update this section as we add new features in the 5.0 series, so
that everybody can follow the development process.

This section documents all enhancements, changes, and bug fixes made to
MySQL Enterprise Server and MySQL Community Server.

Releases in MySQL Enterprise Server are divided into the following
release packs:

   * _Rapid Update Service Packs_ are issued once a month and
     incorporate all the bug fixes and security updates introduced
     since the previous MySQL Enterprise Server release. A single
     Service Pack can be used to update MySQL Enterprise Server; it is
     not necessary to install intervening service packs to bring your
     system up to date.

   * _Quarterly Service Packs_ are issued each quarter and incorporate
     all the bug fixes and security updates introduced up to the Rapid
     Update that the QSP it is based on, and possibly some critical bug
     fixes and security updates from later releases. A single Service
     Pack can be used to update MySQL Enterprise Server; it is not
     necessary to install intervening service packs to bring your
     system up to date.

   * _Hot-fix releases_ incorporate fixes for bugs that caused
     significant issues that are not released as part of a Service Pack.

Note that we tend to update the manual at the same time we make changes
to MySQL. If you find a recent version of MySQL listed here that you
can't find on our download page (`http://dev.mysql.com/downloads/'), it
means that the version has not yet been released (and will normally be
marked so in the appropriate Release Note section).

The date mentioned with a release version is the date of the last
Bazaar commit on which the release was based, not the date when the
packages were made available. The binaries are usually made available a
few days after the date of the tagged ChangeSet, because building and
testing all packages takes some time.

For information on how to determine your current version and release
type, see *Note installation-version::.

The manual included in the source and binary distributions may not be
fully accurate when it comes to the release changelog entries, because
the integration of the manual happens at build time. For the most
up-to-date release changelog, please refer to the online version
instead.


File: manual.info,  Node: news-5-0-x,  Next: mysql-cluster-change-history,  Prev: news,  Up: news

D.1 Changes in Release 5.0.x (Production)
=========================================

* Menu:

* news-5-0-94::                  Changes in MySQL 5.0.94 (05 July 2011)
* news-5-0-93::                  Changes in MySQL 5.0.93 (05 May 2011)
* news-5-0-92::                  Changes in MySQL 5.0.92 (07 February 2011)
* news-5-0-91::                  Changes in MySQL 5.0.91 (05 May 2010)
* news-5-0-90::                  Changes in MySQL 5.0.90 (15 January 2010)
* news-5-0-89::                  Changes in MySQL 5.0.89 (02 December 2009)
* news-5-0-88::                  Changes in MySQL 5.0.88 (04 November 2009)
* news-5-0-87sp1::               Changes in MySQL Enterprise 5.0.87sp1 [QSP] (03 February 2010)
* news-5-0-87::                  Changes in MySQL 5.0.87 (15 October 2009)
* news-5-0-86::                  Changes in MySQL 5.0.86 (09 September 2009)
* news-5-0-85::                  Changes in MySQL 5.0.85 (11 August 2009)
* news-5-0-84sp1::               Changes in MySQL Enterprise 5.0.84sp1 [QSP] (30 September 2009)
* news-5-0-84::                  Changes in MySQL 5.0.84 (07 July 2009)
* news-5-0-83::                  Changes in MySQL 5.0.83 (29 May 2009)
* news-5-0-82sp1::               Changes in MySQL Enterprise 5.0.82sp1 [QSP] (21 July 2009)
* news-5-0-82::                  Changes in MySQL 5.0.82 (20 May 2009)
* news-5-0-81::                  Changes in MySQL Community Server 5.0.81 (01 May 2009)
* news-5-0-80::                  Changes in MySQL Enterprise 5.0.80 [MRU] (01 May 2009)
* news-5-0-79::                  Changes in MySQL Enterprise 5.0.79 [MRU] (09 March 2009)
* news-5-0-78::                  Changes in MySQL Enterprise 5.0.78 [MRU] (06 February 2009)
* news-5-0-77::                  Changes in MySQL Community Server 5.0.77 (28 January 2009)
* news-5-0-76::                  Changes in MySQL Enterprise 5.0.76 [MRU] (05 January 2009)
* news-5-0-75::                  Changes in MySQL Community Server 5.0.75 (17 December 2008)
* news-5-0-74sp1::               Changes in MySQL Enterprise 5.0.74sp1 [QSP] (30 April 2009)
* news-5-0-74::                  Changes in MySQL Enterprise 5.0.74 [MRU] (03 December 2008)
* news-5-0-72sp1::               Changes in MySQL Enterprise 5.0.72sp1 [QSP] (13 January 2009)
* news-5-0-72::                  Changes in MySQL Enterprise 5.0.72 [MRU] (24 October 2008)
* news-5-0-70::                  Changes in MySQL Enterprise 5.0.70 [MRU] (27 September 2008)
* news-5-0-68::                  Changes in MySQL Enterprise 5.0.68 [MRU] (13 August 2008)
* news-5-0-67::                  Changes in MySQL Community Server 5.0.67 (04 August 2008)
* news-5-0-66sp1::               Changes in MySQL Enterprise 5.0.66sp1 [QSP] (23 October 2008)
* news-5-0-66a::                 Changes in MySQL Enterprise 5.0.66a [MRU] (16 July 2008)
* news-5-0-66::                  Changes in MySQL Enterprise 5.0.66 [MRU] (09 July 2008)
* news-5-0-64::                  Changes in MySQL Enterprise 5.0.64 [MRU] (10 June 2008)
* news-5-0-62::                  Changes in MySQL Enterprise 5.0.62 [MRU] (12 May 2008)
* news-5-0-60sp1::               Changes in MySQL Enterprise 5.0.60sp1 [QSP] (27 June 2008)
* news-5-0-60::                  Changes in MySQL Enterprise 5.0.60 [MRU] (28 April 2008)
* news-5-0-58::                  Changes in MySQL Enterprise 5.0.58 [MRU] (05 March 2008)
* news-5-0-56sp1::               Changes in MySQL Enterprise 5.0.56sp1 [QSP] (30 March 2008)
* news-5-0-56::                  Changes in MySQL Enterprise 5.0.56 [MRU] (06 February 2008)
* news-5-0-54a::                 Changes in MySQL Enterprise 5.0.54a [MRU] (11 January 2008)
* news-5-0-54::                  Changes in MySQL Enterprise 5.0.54 [MRU] (14 December 2007)
* news-5-0-52::                  Changes in MySQL Enterprise 5.0.52 [MRU] (30 November 2007)
* news-5-0-51b::                 Changes in MySQL Community Server 5.0.51b (24 April 2008)
* news-5-0-51a::                 Changes in MySQL Community Server 5.0.51a (11 January 2008)
* news-5-0-51::                  Changes in MySQL Community Server 5.0.51 (15 November 2007)
* news-5-0-50sp1a::              Changes in MySQL Enterprise 5.0.50sp1a [QSP] (11 January 2008)
* news-5-0-50sp1::               Changes in MySQL Enterprise 5.0.50sp1 [QSP] (12 December 2007)
* news-5-0-50::                  Changes in MySQL Enterprise 5.0.50 [MRU] (19 October 2007)
* news-5-0-48::                  Changes in MySQL Enterprise 5.0.48 [MRU] (27 August 2007)
* news-5-0-46::                  Changes in MySQL Enterprise 5.0.46 [MRU] (13 July 2007)
* news-5-0-45::                  Changes in MySQL Community Server 5.0.45 (04 July 2007)
* news-5-0-44sp1::               Changes in MySQL Enterprise 5.0.44sp1 [QSP] (01 August 2007)
* news-5-0-44::                  Changes in MySQL Enterprise 5.0.44 [MRU] (21 June 2007)
* news-5-0-42::                  Changes in MySQL Enterprise 5.0.42 [MRU] (23 May 2007)
* news-5-0-41::                  Changes in MySQL Community Server 5.0.41 (01 May 2007)
* news-5-0-40::                  Changes in MySQL Enterprise 5.0.40 [MRU] (17 April 2007)
* news-5-0-38::                  Changes in MySQL Enterprise 5.0.38 [MRU] (20 March 2007)
* news-5-0-37::                  Changes in MySQL Community Server 5.0.37 (27 February 2007)
* news-5-0-36sp1::               Changes in MySQL Enterprise 5.0.36sp1 [QSP] (12 April 2007)
* news-5-0-36::                  Changes in MySQL Enterprise 5.0.36 [MRU] (20 February 2007)
* news-5-0-34::                  Changes in MySQL Enterprise 5.0.34 [MRU] (17 January 2007)
* news-5-0-33::                  Changes in MySQL Community Server 5.0.33 (09 January 2007)
* news-5-0-32::                  Changes in MySQL Enterprise 5.0.32 [MRU] (20 December 2006)
* news-5-0-30sp1::               Changes in MySQL Enterprise 5.0.30sp1 [QSP] (19 January 2007)
* news-5-0-30::                  Changes in MySQL Enterprise 5.0.30 [MRU] (14 November 2006)
* news-5-0-28::                  Changes in MySQL Enterprise 5.0.28 (24 October 2006)
* news-5-0-27::                  Changes in MySQL Community Server 5.0.27 (21 October 2006)
* news-5-0-26::                  Changes in MySQL 5.0.26 (03 October 2006)
* news-5-0-25::                  Changes in MySQL 5.0.25 (15 September 2006)
* news-5-0-24a::                 Changes in MySQL 5.0.24a (25 August 2006)
* news-5-0-24::                  Changes in MySQL 5.0.24 (27 July 2006)
* news-5-0-23::                  Changes in MySQL 5.0.23 (Not released)
* news-5-0-22::                  Changes in MySQL 5.0.22 (24 May 2006)
* news-5-0-21::                  Changes in MySQL 5.0.21 (02 May 2006)
* news-5-0-20a::                 Changes in MySQL 5.0.20a (18 April 2006)
* news-5-0-20::                  Changes in MySQL 5.0.20 (31 March 2006)
* news-5-0-19::                  Changes in MySQL 5.0.19 (04 March 2006)
* news-5-0-18::                  Changes in MySQL 5.0.18 (21 December 2005)
* news-5-0-17::                  Changes in MySQL 5.0.17 (14 December 2005)
* news-5-0-16::                  Changes in MySQL 5.0.16 (10 November 2005)
* news-5-0-15::                  Changes in MySQL 5.0.15 (19 October 2005 Production)
* news-5-0-14::                  Changes in MySQL 5.0.14 (Not released)
* news-5-0-13::                  Changes in MySQL 5.0.13 (22 September 2005 Release Candidate)
* news-5-0-12::                  Changes in MySQL 5.0.12 (02 September 2005)
* news-5-0-11::                  Changes in MySQL 5.0.11 (06 August 2005)
* news-5-0-10::                  Changes in MySQL 5.0.10 (27 July 2005)
* news-5-0-9::                   Changes in MySQL 5.0.9 (15 July 2005)
* news-5-0-8::                   Changes in MySQL 5.0.8 (Not released)
* news-5-0-7::                   Changes in MySQL 5.0.7 (10 June 2005)
* news-5-0-6::                   Changes in MySQL 5.0.6 (26 May 2005)
* news-5-0-5::                   Changes in MySQL 5.0.5 (Not released)
* news-5-0-4::                   Changes in MySQL 5.0.4 (16 April 2005)
* news-5-0-3::                   Changes in MySQL 5.0.3 (23 March 2005 Beta)
* news-5-0-2::                   Changes in MySQL 5.0.2 (01 December 2004)
* news-5-0-1::                   Changes in MySQL 5.0.1 (27 July 2004)
* news-5-0-0::                   Changes in MySQL 5.0.0 (22 December 2003 Alpha)

End of Product Lifecycle

Active development for MySQL Database Server version 5.0 has ended.
Oracle offers various support offerings which may be of interest. For
details and more information, see the MySQL section of the Lifetime
Support Policy for Oracle Technology Products
(http://www.oracle.com/us/support/lifetime-support/index.html). Please
consider upgrading to a recent version.

An overview of features added in MySQL 5.0 can be found here: *Note
mysql-nutshell::.

The following list summarizes what has been done in MySQL 5.0. For a
full list of changes, please refer to the changelog sections for
individual 5.0 releases.

For discussion of upgrade issues that you may encounter for upgrades
from MySQL 4.1 to MySQL 5.0, see *Note upgrading-from-previous-series::.

   * *Note `VARCHAR': char. and *Note `VARBINARY': binary-varbinary.
     columns retain trailing spaces. A `VARCHAR()' or *Note
     `VARBINARY': binary-varbinary. column can contain up to 65,535
     characters or bytes, respectively.

   * Strict SQL mode, which causes an error instead of a warning when
     inserting an incorrect value into a column. See *Note
     server-sql-mode::.

   * A new fixed-point math library supports precision math, resulting
     in more accurate results when working with the *Note `DECIMAL':
     numeric-types. and *Note `NUMERIC': numeric-types. data types. For
     details, see *Note precision-math::.

   * Basic support for views. See *Note views::.

   * Basic support for stored procedures and functions (SQL:2003
     style). See *Note stored-routines::.

   * Basic support for triggers. See *Note triggers::.

   * Basic support for read-only server side cursors. For information
     about using cursors within stored routines, see *Note cursors::.
     For information about using cursors from within the C API, see
     *Note mysql-stmt-attr-set::.

   * Support for `SELECT INTO LIST_OF_VARS', where the variables can be
     a mix of global and local types. See *Note select-into::.

   * `MEMORY' (`HEAP') tables can have *Note `VARCHAR': char. columns.

   * When using a constant string or a function that generates a string
     result in `CREATE ... SELECT', MySQL creates the result column
     based on the maximum length of the string or expression:

     Maximum Length          Data type
     = 0                     `CHAR(0)'
     < 512                   `VARCHAR(MAX_LENGTH)'
     >= 512                  *Note `TEXT': blob.

   * Removed the update log. It is fully replaced by the binary log.
     If the MySQL server is started with `--log-update', it is
     translated to `--log-bin' (or ignored if the server is explicitly
     started with `--log-bin'), and a warning message is written to the
     error log. Setting `sql_log_update' silently sets `sql_log_bin'
     instead (or do nothing if the server is explicitly started with
     `--log-bin').

   * Removed support for the `ISAM' storage engine.  If you have `ISAM'
     tables, you should convert them before upgrading. See *Note
     upgrading-from-previous-series::.

   * Removed support for `RAID' options in `MyISAM' tables. If you have
     tables that use these options, you should convert them before
     upgrading. See *Note upgrading-from-previous-series::.


File: manual.info,  Node: news-5-0-94,  Next: news-5-0-93,  Prev: news-5-0-x,  Up: news-5-0-x

D.1.1 Changes in MySQL 5.0.94 (05 July 2011)
--------------------------------------------

End of Product Lifecycle

Active development for MySQL Database Server version 5.0 has ended.
Oracle offers various support offerings which may be of interest. For
details and more information, see the MySQL section of the Lifetime
Support Policy for Oracle Technology Products
(http://www.oracle.com/us/support/lifetime-support/index.html). Please
consider upgrading to a recent version.

*Bugs Fixed*

   * Some files in the MySQL Server sources containing legacy code
     still used the LGPL license. Such files that were no longer in use
     have been removed. Any such code that remains following this
     removal now appears under the GPL only.  (Bug #11896296) See also
     Bug #11840513.


File: manual.info,  Node: news-5-0-93,  Next: news-5-0-92,  Prev: news-5-0-94,  Up: news-5-0-x

D.1.2 Changes in MySQL 5.0.93 (05 May 2011)
-------------------------------------------

End of Product Lifecycle

Active development for MySQL Database Server version 5.0 has ended.
Oracle offers various support offerings which may be of interest. For
details and more information, see the MySQL section of the Lifetime
Support Policy for Oracle Technology Products
(http://www.oracle.com/us/support/lifetime-support/index.html). Please
consider upgrading to a recent version.

*Bugs Fixed*

   * *Security Fix*: The `PolyFromWKB()' function could crash the
     server when improper WKB data was passed to the function.  (Bug
     #51875, CVE-2010-3840)

   * *Security Fix*: Bug #49124 and Bug #11757121 were fixed.

   * *Security Fix*: Bug #36544 was fixed.

   * Two unused test files in `storage/ndb/test/sql' contained incorrect
     versions of the GNU Lesser General Public License. The files and
     the directory containing them have been removed.  (Bug #11810224)
     See also Bug #11810156.

   * On FreeBSD and OpenBSD, the server incorrectly checked the range
     of the system date, causing legal values to be rejected.  (Bug
     #55755, Bug #11763089)


File: manual.info,  Node: news-5-0-92,  Next: news-5-0-91,  Prev: news-5-0-93,  Up: news-5-0-x

D.1.3 Changes in MySQL 5.0.92 (07 February 2011)
------------------------------------------------

End of Product Lifecycle

Active development for MySQL Database Server version 5.0 has ended.
Oracle offers various support offerings which may be of interest. For
details and more information, see the MySQL section of the Lifetime
Support Policy for Oracle Technology Products
(http://www.oracle.com/us/support/lifetime-support/index.html). Please
consider upgrading to a recent version.

This section documents all changes and bugfixes that have been applied
since the last MySQL Enterprise Server and MySQL Community Server
release (5.0.91). If you would like to receive more fine-grained and
personalized _update alerts_ about fixes that are relevant to the
version and features you use, please consider subscribing to _MySQL
Enterprise_ (a commercial MySQL offering). For more details please see
http://www.mysql.com/products/enterprise/advisors.html.

*Functionality Added or Changed*

   * The time zone tables available at
     `http://dev.mysql.com/downloads/timezones.html' have been updated.
     These tables can be used on systems such as Windows or HP-UX that
     do not include zoneinfo files.  (Bug #40230)

*Bugs Fixed*

   * *Security Fix*: Bug #57952 was fixed.

   * *Security Fix*: During evaluation of arguments to extreme-value
     functions such as `LEAST()' and `GREATEST()', type errors did not
     propagate properly, causing the server to crash.  (Bug #55826,
     CVE-2010-3833)

   * *Security Fix*: The server could crash after materializing a
     derived table that required a temporary table for grouping.  (Bug
     #55568, CVE-2010-3834)

   * *Security Fix*: A user-variable assignment expression that is
     evaluated in a logical expression context can be precalculated in
     a temporary table for `GROUP BY'. However, when the expression
     value is used after creation of the temporary table, it was
     re-evaluated, not read from the table, and a server crash resulted.
     (Bug #55564, CVE-2010-3835)

   * *Security Fix*: Joins involving a table with a unique *Note `SET':
     set. column could cause a server crash.  (Bug #54575,
     CVE-2010-3677)

   * *Security Fix*: Pre-evaluation of `LIKE' predicates during view
     preparation could cause a server crash.  (Bug #54568, Bug
     #11762026, CVE-2010-3836)

   * *Security Fix*: `GROUP_CONCAT()' and `WITH ROLLUP' together could
     cause a server crash.  (Bug #54476, CVE-2010-3837)

   * *Security Fix*: Queries could cause a server crash if the
     `GREATEST()' or `LEAST()' function had a mixed list of numeric and
     *Note `LONGBLOB': blob.  arguments, and the result of such a
     function was processed using an intermediate temporary table.
     (Bug #54461, CVE-2010-3838)

   * *Security Fix*: Bug #53933 was fixed.

   * *Security Fix*: Bug #53907 was fixed.

   * *Security Fix*: Using *Note `EXPLAIN': explain. with queries of the
     form `SELECT ... UNION ... ORDER BY (SELECT ... WHERE ...)' could
     cause a server crash.  (Bug #52711, CVE-2010-3682)

   * *Security Fix*: Bug #52357 was fixed.

   * *Security Fix*: Bug #52315 was fixed.

   * *Security Fix*: Bug #48157 was fixed.

   * *InnoDB Storage Engine*: Creating or dropping a table with 1023
     transactions active caused an assertion failure.  (Bug #49238)

   * The `make_binary_distribution' target to `make' could fail on some
     platforms because the lines generated were too long for the shell.
     (Bug #54590)

   * A client could supply data in chunks to a prepared statement
     parameter other than of type *Note `TEXT': blob.  or *Note `BLOB':
     blob. using the *Note `mysql_stmt_send_long_data()':
     mysql-stmt-send-long-data. C API function (or
     `COM_STMT_SEND_LONG_DATA' command). This led to a crash because
     other data types are not valid for long data.  (Bug #54041)

   * Builds of the embedded *Note `mysqld': mysqld. failed due to a
     missing element of the `struct NET'.  (Bug #53908, Bug #53912)

   * The definition of the `MY_INIT' macro in `my_sys.h' included an
     extraneous semicolon, which could cause compilation failure.  (Bug
     #53906)

   * If the remote server for a *Note `FEDERATED':
     federated-storage-engine. table could not be accessed, queries for
     the *Note `INFORMATION_SCHEMA.TABLES': tables-table. table failed.
     (Bug #35333)

   * *Note `mysqld': mysqld. could fail during execution when using SSL.
     (Bug #34236)

   * Threads that were calculating the estimated number of records for
     a range scan did not respond to the *Note `KILL': kill. statement.
     That is, if a `range' join type is possible (even if not selected
     by the optimizer as a join type of choice and thus not shown by
     *Note `EXPLAIN': explain.), the query in the `statistics' state
     (shown by the *Note `SHOW PROCESSLIST': show-processlist.) did not
     respond to the *Note `KILL': kill. statement.  (Bug #25421)


File: manual.info,  Node: news-5-0-91,  Next: news-5-0-90,  Prev: news-5-0-92,  Up: news-5-0-x

D.1.4 Changes in MySQL 5.0.91 (05 May 2010)
-------------------------------------------

End of Product Lifecycle

Active development for MySQL Database Server version 5.0 has ended.
Oracle offers various support offerings which may be of interest. For
details and more information, see the MySQL section of the Lifetime
Support Policy for Oracle Technology Products
(http://www.oracle.com/us/support/lifetime-support/index.html). Please
consider upgrading to a recent version.

This section documents all changes and bugfixes that have been applied
since the last MySQL Enterprise Server and MySQL Community Server
release (5.0.90). If you would like to receive more fine-grained and
personalized _update alerts_ about fixes that are relevant to the
version and features you use, please consider subscribing to _MySQL
Enterprise_ (a commercial MySQL offering). For more details please see
http://www.mysql.com/products/enterprise/advisors.html.

*icc Notes*
   * This is the final release of MySQL 5.0 for which Generic Linux
     MySQL binary packages built with the `icc' compiler on x86 and
     x86_64 will be offered. These were previously produced as an
     alternative to our main packages built using `gcc', as they
     provided noticeable performance benefits. In recent times the
     performance differences have diminished and build and runtime
     problems have surfaced, thus it is no longer viable to continue
     producing them.

     We continue to use the `icc' compiler to produce our
     distribution-specific RPM packages on ia64.

*Bugs Fixed*

   * *Security Fix*: The server failed to check the table name argument
     of a `COM_FIELD_LIST' command packet for validity and compliance
     to acceptable table name standards. This could be exploited to
     bypass almost all forms of checks for privileges and table-level
     grants by providing a specially crafted table name argument to
     `COM_FIELD_LIST'.

     In MySQL 5.0 and above, this permitted an authenticated user with
     `SELECT' privileges on one table to obtain the field definitions
     of any table in all other databases and potentially of other MySQL
     instances accessible from the server's file system.

     Additionally, for MySQL version 5.1 and above, an authenticated
     user with `DELETE' or `SELECT' privileges on one table could
     delete or read content from any other table in all databases on
     this server, and potentially of other MySQL instances accessible
     from the server's file system.  (Bug #53371, CVE-2010-1848)

   * *Security Fix*: The server was susceptible to a buffer-overflow
     attack due to a failure to perform bounds checking on the table
     name argument of a `COM_FIELD_LIST' command packet. By sending
     long data for the table name, a buffer is overflown, which could
     be exploited by an authenticated user to inject malicious code.
     (Bug #53237, CVE-2010-1850)

   * *Security Fix*: The server could be tricked into reading packets
     indefinitely if it received a packet larger than the maximum size
     of one packet.  (Bug #50974, CVE-2010-1849)

   * The optimizer could attempt to evaluate the `WHERE' clause before
     any rows had been read, resulting in a server crash.  (Bug #52177)

   * On Windows, `LOAD_FILE()' could cause a crash for some pathnames.
     (Bug #51893)

   * Use of *Note `HANDLER': handler. statements with tables that had
     spatial indexes caused a server crash.  (Bug #51357)

   * With an XA transaction active, *Note `SET autocommit = 1':
     set-option. could cause side effects such as memory corruption or
     a server crash.  (Bug #51342)

   * The SSL certificates in the test suite were about to expire.  They
     have been updated with expiration dates in the year 2015.  (Bug
     #50642)

   * For debug builds, an assertion was incorrectly raised in the
     optimizer when matching `ORDER BY' expressions.  (Bug #50335)

   * The `filesort' sorting method applied to a *Note `CHAR(0)': char.
     column could lead to a server crash.  (Bug #49897)

   * `sql_buffer_result' had an effect on non-*Note `SELECT': select.
     statements, contrary to the documentation.  (Bug #49552)

   * *Note `EXPLAIN EXTENDED': explain. crashed trying to print column
     names for a subquery in the `FROM' clause when the table had gone
     out of scope.  (Bug #49487)

   * `mysql-test-run.pl' now recognizes the `MTR_TESTCASE_TIMEOUT',
     `MTR_SUITE_TIMEOUT', `MTR_SHUTDOWN_TIMEOUT', and
     `MTR_START_TIMEOUT' environment variables. If they are set, their
     values are used to set the `--testcase-timeout', `--suite-timeout',
     `--shutdown-timeout', and `--start-timeout' options, respectively.
     (Bug #49210)

   * Certain `INTERVAL' expressions could cause a crash on 64-bit
     systems.  (Bug #48739)

   * The server crashed when it could not determine the best execution
     plan for queries involving outer joins with nondeterministic `ON'
     clauses such as the ones containing the `RAND()' function, a
     user-defined function, or a `NOT DETERMINISTIC' stored function.
     (Bug #48483)

   * If an outer query was invalid, a subquery might not be set up.
     *Note `EXPLAIN EXTENDED': explain. did not expect this and caused
     a crash by trying to dereference improperly set up information.
     (Bug #48295)


File: manual.info,  Node: news-5-0-90,  Next: news-5-0-89,  Prev: news-5-0-91,  Up: news-5-0-x

D.1.5 Changes in MySQL 5.0.90 (15 January 2010)
-----------------------------------------------

End of Product Lifecycle

Active development for MySQL Database Server version 5.0 has ended.
Oracle offers various support offerings which may be of interest. For
details and more information, see the MySQL section of the Lifetime
Support Policy for Oracle Technology Products
(http://www.oracle.com/us/support/lifetime-support/index.html). Please
consider upgrading to a recent version.

This section documents all changes and bugfixes that have been applied
since the last MySQL Enterprise Server and MySQL Community Server
release (5.0.89). If you would like to receive more fine-grained and
personalized _update alerts_ about fixes that are relevant to the
version and features you use, please consider subscribing to _MySQL
Enterprise_ (a commercial MySQL offering). For more details please see
http://www.mysql.com/products/enterprise/advisors.html.

*Bugs Fixed*

   * *Security Fix*: For servers built with yaSSL, a preauthorization
     buffer overflow could cause memory corruption or a server crash.
     We thank Evgeny Legerov from Intevydis for providing us with a
     proof-of-concept script that permitted us to reproduce this bug.
     (Bug #50227, CVE-2009-4484)

   * *Replication*: *Note `FLUSH LOGS': flush. did not close and reopen
     the binary log index file.  (Bug #48738) See also Bug #34582.

   * Some prepared statements could raise an assertion when re-executed.
     (Bug #49570)

   * Valgrind warnings for *Note `CHECKSUM TABLE': checksum-table. were
     corrected.  (Bug #49465)

   * Specifying an index algorithm (such as `BTREE') for `SPATIAL' or
     `FULLTEXT' indexes caused a server crash. These index types do not
     support algorithm specification, and it is not longer permitted to
     do so.  (Bug #49250)

   * The optimizer sometimes incorrectly handled conditions of the form
     `WHERE COL_NAME='CONST1' AND COL_NAME='CONST2''.  (Bug #49199)

   * Several `strmake()' calls had an incorrect length argument (too
     large by one).  (Bug #48983)

   * On Fedora 12, `strmov()' did not guarantee correct operation for
     overlapping source and destination buffer.  Calls were fixed to
     use an overlap-safe version instead.  (Bug #48866)

   * Incomplete reset of internal `TABLE' structures could cause a
     crash with `eq_ref' table access in subqueries.  (Bug #48709)

   * Re-execution of a prepared statement could cause a server crash.
     (Bug #48508)

   * The error message for `ER_UPDATE_INFO' was subject to buffer
     overflow or truncation.  (Bug #48500)

   * On Solaris, the server printed no stack trace to the error log
     after a crash.  (Bug #47391)

   * A crash occurred when a user variable that was assigned to a
     subquery result was used as a result field in a *Note `SELECT':
     select. statement with aggregate functions.  (Bug #47371)

   * Comparison with `NULL' values sometimes did not produce a correct
     result.  (Bug #42760)

   * When compressed *Note `MyISAM': myisam-storage-engine. files were
     opened, they were always memory mapped, sometimes causing
     memory-swapping problems. To deal with this, a new system
     variable, `myisam_mmap_size', was added to permit limiting the
     amount of memory used for memory mapping of *Note `MyISAM':
     myisam-storage-engine. files.  (Bug #37408)


File: manual.info,  Node: news-5-0-89,  Next: news-5-0-88,  Prev: news-5-0-90,  Up: news-5-0-x

D.1.6 Changes in MySQL 5.0.89 (02 December 2009)
------------------------------------------------

End of Product Lifecycle

Active development for MySQL Database Server version 5.0 has ended.
Oracle offers various support offerings which may be of interest. For
details and more information, see the MySQL section of the Lifetime
Support Policy for Oracle Technology Products
(http://www.oracle.com/us/support/lifetime-support/index.html). Please
consider upgrading to a recent version.

This section documents all changes and bugfixes that have been applied
since the last MySQL Enterprise Server and MySQL Community Server
release (5.0.88). If you would like to receive more fine-grained and
personalized _update alerts_ about fixes that are relevant to the
version and features you use, please consider subscribing to _MySQL
Enterprise_ (a commercial MySQL offering). For more details please see
http://www.mysql.com/products/enterprise/advisors.html.

*Bugs Fixed*

   * Privileges for stored routines were ignored for mixed-case routine
     names.  (Bug #48872) See also Bug #41049.

   * Building MySQL on Fedora Core 12 64-bit failed, due to errors in
     *Note `comp_err': comp-err.  (Bug #48864)

   * `DISTINCT' was ignored for queries with `GROUP BY WITH ROLLUP' and
     only `const' tables.  (Bug #48475)

   * Loose index scan was inappropriately chosen for some `WHERE'
     conditions.  (Bug #48472)

   * A bad typecast could cause query execution to allocate large
     amounts of memory.  (Bug #48458)

   * *Note `mysql_secure_installation': mysql-secure-installation. did
     not work on Solaris.  (Bug #48086)

   * When running *Note `mysql_secure_installation':
     mysql-secure-installation, the command failed if the `root'
     password contained multiple space, `'\'', `'#'', or quote
     characters.  (Bug #48031)

   * `InnoDB' did not disallow creation of an index with the name
     `GEN_CLUST_INDEX', which is used internally.  (Bug #46000)

   * Use of *Note `InnoDB': innodb-storage-engine. monitoring (*Note
     `SHOW ENGINE INNODB STATUS': show-engine. or one of the *Note
     `InnoDB': innodb-storage-engine. Monitor tables) could cause a
     server crash due to invalid access to a shared variable in a
     concurrent environment.  (Bug #38883)

   * Output from *Note `mysql --html': mysql. did not encode the `'<'',
     `'>'', or `'&'' characters.  (Bug #27884)


File: manual.info,  Node: news-5-0-88,  Next: news-5-0-87sp1,  Prev: news-5-0-89,  Up: news-5-0-x

D.1.7 Changes in MySQL 5.0.88 (04 November 2009)
------------------------------------------------

This section documents all changes and bugfixes that have been applied
since the last MySQL Enterprise Server and MySQL Community Server
release (5.0.87). If you would like to receive more fine-grained and
personalized _update alerts_ about fixes that are relevant to the
version and features you use, please consider subscribing to _MySQL
Enterprise_ (a commercial MySQL offering). For more details please see
http://www.mysql.com/products/enterprise/advisors.html.

*Bugs Fixed*

   * *Security Fix*: MySQL clients linked against OpenSSL could be
     tricked not to check server certificates.  (Bug #47320,
     CVE-2009-4028)

   * *MySQL Cluster*: When a data node had written its GCI marker to
     the first page of a megabyte, and that node was later killed
     during restart after having processed that page (marker) but
     before completing a LCP, the data node could fail with file system
     errors.  (Bug #44952) See also Bug #42564, Bug #44291.

   * *Replication*: When a session was closed on the master, temporary
     tables belonging to that session were logged with the wrong
     database names when either of the following conditions was true:

       1. The length of the name of the database to which the temporary
          table belonged was greater than the length of the current
          database name.

       2. The current database was not set.

     (Bug #48216) See also Bug #46861, Bug #48297.

   * A query containing a view using temporary tables and multiple
     tables in the `FROM' clause and `PROCEDURE ANALYSE()' caused a
     server crash.

     As a result of this bug fix, `PROCEDURE ANALYSE()' is legal only
     in a top-level `SELECT'.  (Bug #48293) See also Bug #46184.

   * Error handling was missing for *Note `SELECT': select. statements
     containing subqueries in the `WHERE' clause and that assigned a
     *Note `SELECT': select. result to a user variable. The server
     could crash as a result.  (Bug #48291)

   * An assertion could fail if the optimizer used a `SPATIAL' index.
     (Bug #48258, Bug #47019)

   * A combination of `GROUP BY WITH ROLLUP', `DISTINCT' and the
     `const' join type in a query caused a server crash when the
     optimizer used a temporary table to resolve `DISTINCT'.  (Bug
     #48131)

   * `mysys/mf_keycache.c' requires threading, but no test was made for
     thread support.  (Bug #47923)

   * If the first argument to `GeomFromWKB()' function was a geometry
     value, the function just returned its value. However, it failed to
     preserve the argument's `null_value' flag, which caused an
     unexpected `NULL' value to be returned to the caller, resulting in
     a server crash.  (Bug #47780)

   * The GPL and commercial license headers had different sizes, so
     that error log, backtrace, core dump, and cluster trace file line
     numbers could be off by one if they were not checked against the
     version of the source used for the build. (For example, checking a
     GPL build backtrace against commercial sources.)  (Bug #46216)

   * During the build of the Red Hat IA64 MySQL server RPM, the system
     library link order was incorrect. This made the resulting Red Hat
     IA64 RPM depend on "libc.so.6.1(GLIBC_PRIVATE)(64bit)", thus
     preventing installation of the package.  (Bug #45706)

   * Failure to treat *Note `BIT': numeric-types. values as unsigned
     could lead to unpredictable results.  (Bug #42803)

   * Some queries with nested outer joins could lead to crashes or
     incorrect results because an internal data structure was handled
     improperly.  (Bug #42116)

   * In a replication scenario with `innodb_locks_unsafe_for_binlog'
     enabled on the slave, where rows were changed only on the slave
     (not through replication), in some rare cases, many messages of
     the following form were written to the slave error log: `InnoDB:
     Error: unlock row could not find a 4 mode lock on the record'.
     (Bug #41756)

   * A stub of the previously removed `mysql_odbc_escape_string()'
     function was restored to fix a ABI breakage. The function was
     intended to be private and used only by Connector/ODBC, but,
     unfortunately, it was exported as part of the ABI. Nonetheless,
     only a stub is restored as the original function is inherently
     broken and should not be used.  (Bug #41728) See also Bug #29592.

   * After renaming a user, granting that user privileges could result
     in the user having privileges additional to those granted.  (Bug
     #41597)

   * In some cases, the server did not recognize lettercase differences
     between *Note `GRANT': grant.  attributes such as table name or
     user name. For example, a user was able to perform operations on a
     table with privileges of another user with the same user name but
     in a different lettercase.

     In consequence of this bug fix, the collation for the
     `Routine_name' column of the `mysql.proc' table is changed from
     `utf8_bin' to `utf8_general_ci'.  (Bug #41049) See also Bug #48872.


File: manual.info,  Node: news-5-0-87sp1,  Next: news-5-0-87,  Prev: news-5-0-88,  Up: news-5-0-x

D.1.8 Changes in MySQL Enterprise 5.0.87sp1 [QSP] (03 February 2010)
--------------------------------------------------------------------

This is a _Service Pack_ release of the MySQL Enterprise Server 5.0.

This section documents all changes and bugfixes that have been applied
since the last MySQL Enterprise Server release (5.0.87).

If you would like to receive more fine-grained and personalized _update
alerts_ about fixes that are relevant to the version and features you
use, please consider subscribing to _MySQL Enterprise_ (a commercial
MySQL offering). For more details please see
http://www.mysql.com/products/enterprise/advisors.html.

*Bugs Fixed*

   * *Security Fix*: For servers built with yaSSL, a preauthorization
     buffer overflow could cause memory corruption or a server crash.
     We thank Evgeny Legerov from Intevydis for providing us with a
     proof-of-concept script that permitted us to reproduce this bug.
     (Bug #50227, CVE-2009-4484)

   * *Replication*: When a session was closed on the master, temporary
     tables belonging to that session were logged with the wrong
     database names when either of the following conditions was true:

       1. The length of the name of the database to which the temporary
          table belonged was greater than the length of the current
          database name.

       2. The current database was not set.

     (Bug #48216) See also Bug #46861, Bug #48297.

   * Specifying an index algorithm (such as `BTREE') for `SPATIAL' or
     `FULLTEXT' indexes caused a server crash. These index types do not
     support algorithm specification, and it is not longer permitted to
     do so.  (Bug #49250)

   * Building MySQL on Fedora Core 12 64-bit failed, due to errors in
     *Note `comp_err': comp-err.  (Bug #48864)

   * Re-execution of a prepared statement could cause a server crash.
     (Bug #48508)

   * A bad typecast could cause query execution to allocate large
     amounts of memory.  (Bug #48458)

   * A query containing a view using temporary tables and multiple
     tables in the `FROM' clause and `PROCEDURE ANALYSE()' caused a
     server crash.

     As a result of this bug fix, `PROCEDURE ANALYSE()' is legal only
     in a top-level `SELECT'.  (Bug #48293) See also Bug #46184.

   * Error handling was missing for *Note `SELECT': select. statements
     containing subqueries in the `WHERE' clause and that assigned a
     *Note `SELECT': select. result to a user variable. The server
     could crash as a result.  (Bug #48291)

   * An assertion could fail if the optimizer used a `SPATIAL' index.
     (Bug #48258, Bug #47019)

   * A combination of `GROUP BY WITH ROLLUP', `DISTINCT' and the
     `const' join type in a query caused a server crash when the
     optimizer used a temporary table to resolve `DISTINCT'.  (Bug
     #48131)

   * If the first argument to `GeomFromWKB()' function was a geometry
     value, the function just returned its value. However, it failed to
     preserve the argument's `null_value' flag, which caused an
     unexpected `NULL' value to be returned to the caller, resulting in
     a server crash.  (Bug #47780)

   * In a replication scenario with `innodb_locks_unsafe_for_binlog'
     enabled on the slave, where rows were changed only on the slave
     (not through replication), in some rare cases, many messages of
     the following form were written to the slave error log: `InnoDB:
     Error: unlock row could not find a 4 mode lock on the record'.
     (Bug #41756)

   * In some cases, the server did not recognize lettercase differences
     between *Note `GRANT': grant.  attributes such as table name or
     user name. For example, a user was able to perform operations on a
     table with privileges of another user with the same user name but
     in a different lettercase.

     In consequence of this bug fix, the collation for the
     `Routine_name' column of the `mysql.proc' table is changed from
     `utf8_bin' to `utf8_general_ci'.  (Bug #41049) See also Bug #48872.

   * Use of *Note `InnoDB': innodb-storage-engine. monitoring (*Note
     `SHOW ENGINE INNODB STATUS': show-engine. or one of the *Note
     `InnoDB': innodb-storage-engine. Monitor tables) could cause a
     server crash due to invalid access to a shared variable in a
     concurrent environment.  (Bug #38883)


File: manual.info,  Node: news-5-0-87,  Next: news-5-0-86,  Prev: news-5-0-87sp1,  Up: news-5-0-x

D.1.9 Changes in MySQL 5.0.87 (15 October 2009)
-----------------------------------------------

This section documents all changes and bugfixes that have been applied
since the last MySQL Enterprise Server and MySQL Community Server
release (5.0.86). If you would like to receive more fine-grained and
personalized _update alerts_ about fixes that are relevant to the
version and features you use, please consider subscribing to _MySQL
Enterprise_ (a commercial MySQL offering). For more details please see
http://www.mysql.com/products/enterprise/advisors.html.

*Bugs Fixed*

   * *Incompatible Change*: In binary installations of MySQL, the
     supplied `binary-configure' script would start and configure
     MySQL, even when command help was requested with the `--help'
     command-line option. The `--help' option, if provided, no longer
     starts and installs the server.  (Bug #30954)

   * *Replication*: *Note `BEGIN': commit.  statements were not
     included in the output of *Note `mysqlbinlog': mysqlbinlog.  (Bug
     #46998)

   * *Replication*: Database-level character sets were not always
     honored by the replication SQL thread. This could cause data
     inserted on the master using *Note `LOAD DATA': load-data. to be
     replicated using the wrong character set.  (Bug #45516)

   * *API*: The fix for Bug #24507 could lead in some cases to client
     application failures due to a race condition. Now the server waits
     for the `dummy' thread to return before exiting, thus making sure
     that only one thread can initialize the POSIX threads library.
     (Bug #42850)

   * On Mac OS X or Windows, sending a `SIGHUP' signal to the server or
     an asynchronous flush (triggered by `flush_time') caused the server
     to crash.  (Bug #47525)

   * Solaris binary packages now are compiled with `-g0' rather than
     `-g'.  (Bug #47137)

   * *Note `EXPLAIN': explain. caused a server crash for certain valid
     queries.  (Bug #47106)

   * When creating a new instance on Windows using *Note `mysqld-nt':
     mysqld. and the `--install' parameter, the value of the service
     would be set incorrectly, resulting in a failure to start the
     configured service.  (Bug #46917)

   * `CONCAT_WS()' could return incorrect results due to an argument
     buffer also being used as a result buffer.  (Bug #46815)

   * The server crashed when re-using outer column references in
     correlated subqueries when the enclosing query used a temp table.
     (Bug #46791)

   * The server ignored the setting of `sync_frm' for *Note `CREATE
     TABLE ... LIKE': create-table.  (Bug #46591)

   * An attempt to create a table with the same name as an existing
     view could cause a server crash.  (Bug #46384)

   * A memory leak occurred when *Note `EXPLAIN': explain. encountered
     a malformed query.  (Bug #45989)

   * When re-installing MySQL on Windows on a server that has a data
     directory from a previous MySQL installation, the installer would
     fail to identify the existence of the installation and the
     password configured for the `root' user.  (Bug #45200)

   * Client flags were incorrectly initialized for the embedded server,
     causing several tests in the `jp' test suite to fail.  (Bug #45159)

   * A test for stack growth failed on some platforms, leading to
     server crashes.  (Bug #42213)

   * The server used the wrong lock type (always `TL_READ' instead of
     `TL_READ_NO_INSERT' when appropriate) for tables used in
     subqueries of *Note `UPDATE': update. statements. This led in some
     cases to replication failure because statements were written in
     the wrong order to the binary log.  (Bug #42108)

   * Concurrent execution of *Note `FLUSH TABLES': flush.  along with
     *Note `SHOW FUNCTION STATUS': show-function-status.  or *Note
     `SHOW PROCEDURE STATUS': show-procedure-status. could cause a
     server crash.  (Bug #34895)

   * *Note `myisamchk': myisamchk. performed parameter value casting at
     startup that generated unnecessary warning messages.  (Bug #33785)

   * When building MySQL on Windows from source, the
     `WITH_BERKELEY_STORAGE_ENGINE' option would fail to configure
     `BDB' support correctly.  (Bug #27693)

   * Changing the size of a key buffer that is under heavy use could
     cause a server crash. The fix partially removes the limitation
     that *Note `LOAD INDEX INTO CACHE': load-index. fails unless all
     indexes in a table have the same block size. Now the statement
     fails only if `IGNORE LEAVES' is specified.  (Bug #17332)


File: manual.info,  Node: news-5-0-86,  Next: news-5-0-85,  Prev: news-5-0-87,  Up: news-5-0-x

D.1.10 Changes in MySQL 5.0.86 (09 September 2009)
--------------------------------------------------

This section documents all changes and bugfixes that have been applied
since the last MySQL Enterprise Server and MySQL Community Server
release (5.0.85). If you would like to receive more fine-grained and
personalized _update alerts_ about fixes that are relevant to the
version and features you use, please consider subscribing to _MySQL
Enterprise_ (a commercial MySQL offering). For more details please see
http://www.mysql.com/products/enterprise/advisors.html.

*Bugs Fixed*

   * *Performance*: For `MyISAM' tables with `bulk_insert_buffer_size'
     values larger than 256KB, the performance of bulk insert operations
     such as multiple-row *Note `INSERT': insert. and *Note `INSERT ...
     SELECT': insert. operations has been improved greatly when up to a
     hundred rows are inserted at the same time.  (Bug #44723)

   * *Replication*: When using the `--replicate-rewrite-db' option and
     the database referenced by this option on the master was the
     current database when the connection to the slave was closed, any
     temporary tables existing in this database were not properly
     dropped.  (Bug #46861)

   * *Replication*: In some cases, a *Note `STOP SLAVE': stop-slave.
     statement could cause the replication slave to crash. This issue
     was specific to MySQL on Windows or Macintosh platforms.  (Bug
     #45238, Bug #45242, Bug #45243, Bug #46013, Bug #46014, Bug #46030)
     See also Bug #40796.

   * Stack overflow checking did not account for the size of the
     structure stored in the heap.  (Bug #46807)

   * The server could crash for queries with the following elements: 1.
     An `impossible where' in the outermost `SELECT'; 2. An aggregate
     in the outermost `SELECT'; 3. A correlated subquery with a `WHERE'
     clause that includes an outer field reference as a top-level
     `WHERE' sargable predicate; (Bug #46749)

   * *Note `CREATE TABLE ... SELECT': create-table. could cause
     assertion failure if a table already existed with the same name
     and contained an `AUTO_INCREMENT' column.  (Bug #46616)

   * A query containing a subquery in the `FROM' clause and `PROCEDURE
     ANALYSE()' caused a server crash.  (Bug #46184) See also Bug
     #48293.

   * If `--basedir' was specified, *Note `mysqld_safe': mysqld-safe.
     did not use it when attempting to locate *Note
     `my_print_defaults': my-print-defaults.  (Bug #39326)

   * A buffer overflow could occur during handling of `IS NULL' ranges.
     (Bug #37044)

   * *Note `mysqladmin --wait ping': mysqladmin. crashed on Windows
     systems.  (Bug #35132)


File: manual.info,  Node: news-5-0-85,  Next: news-5-0-84sp1,  Prev: news-5-0-86,  Up: news-5-0-x

D.1.11 Changes in MySQL 5.0.85 (11 August 2009)
-----------------------------------------------

This section documents all changes and bugfixes that have been applied
since the last MySQL Enterprise Server and MySQL Community Server
release (5.0.84). If you would like to receive more fine-grained and
personalized _update alerts_ about fixes that are relevant to the
version and features you use, please consider subscribing to _MySQL
Enterprise_ (a commercial MySQL offering). For more details please see
http://www.mysql.com/products/enterprise/advisors.html.

*Bugs Fixed*

   * *Important Change*: Uninstalling MySQL using the MySQL installer
     on Windows would delete the `my.ini' file. The file is no longer
     deleted. In addition, when a new installation is conducted, any
     existing cofiguration file will be renamed to `myDATETIME.ini.bak'
     during configuration.  (Bug #36493)

   * The server printed warnings at startup about adjusting the value
     of the `max_join_size' system variable. (These were harmless, but
     might be seen by users as significant.)  (Bug #46385)

   * The server crashed if evaluation of `GROUP_CONCAT(... ORDER BY)'
     required allocation of a sort buffer but allocation failed.  (Bug
     #46080)

   * After an error such as a table-full condition, *Note `INSERT
     IGNORE': insert.  could cause an assertion failure for debug
     builds.  (Bug #46075)

   * An optimization that moved an item from a subquery to an outer
     query could cause a server crash.  (Bug #46051)

   * Several Valgrind warnings were corrected.  (Bug #46003, Bug
     #46034, Bug #46042)

   * For problems reading SSL files during SSL initialization, the
     server wrote error messages to `stderr' rather than to the error
     log.  (Bug #45770)

   * The vendor name change from MySQL AB to Sun Microsystems, Inc.  in
     RPM packages was not handled gracefully when upgrading MySQL using
     an RPM package.  (Bug #45534)

   * A Windows Installation using the GUI installer would fail with:

          MySQL Server 5.1 Setup Wizard ended prematurely

          The wizard was interrupted before MySQL Server 5.1. could be completely installed.

          Your system has not been modified. To complete installation at another time, please run
          setup again.

          Click Finish to exit the wizard

     This was due to a step in the MSI installer that could fail to
     execute correctly on some environments.  (Bug #45418)

   * Compiler warnings on Windows were fixed.  (Bug #45287)

   * Invalid memory reads could occur using the compressed
     client/server protocol.  (Bug #45031)

   * Invalid input could cause invalid memory reads by the parser.
     (Bug #45010)

   * Creating a new instance after previously removing an instance
     would fail to complete the installation properly because the
     security settings could not be applied correctly.  (Bug #44428)

   * The server did not always check the return value of calls to the
     `hash_init()' function.  (Bug #43572)

   * A test for stack growth failed on some platforms, leading to
     server crashes.  (Bug #42213)

   * *Note `SHOW PROCESSLIST': show-processlist. could access freed
     memory of a stored procedure run in a concurrent session.  (Bug
     #38816)

   * During installation on Windows, the MySQL Instance Configuration
     Wizard window could be opened at a size too small to be usable.
     (Bug #38723)

   * `make_binary_distribution' did not always generate correct
     distribution names.  (Bug #37808)

   * The server crashed when executing a prepared statement containing
     a duplicated `MATCH()' function call in the select list and `ORDER
     BY' clause; for example, `SELECT MATCH(a) AGAINST('test') FROM t1
     ORDER BY MATCH(a) AGAINST('test')'.  (Bug #37740)

   * When performing an installation on Windows using the GUI
     installer, the installer would fail to wait long enough during
     installation for the MySQL service to be installed, which would
     cause the installation to fail and may cause security settings,
     such as the `root' password to not be applied correctly.  (Bug
     #30525)

   * If `InnoDB' reached its limit on the number of concurrent
     transactions (1023), it wrote a descriptive message to the error
     log but returned a misleading error message to the client, or an
     assertion failure occurred.  (Bug #18828) See also Bug #46672.

   * Installation of MySQL on Windows would fail to set the correct
     location for the character set files, which could lead to *Note
     `mysqld': mysqld. and *Note `mysql': mysql. failing to initialize
     properly.  (Bug #17270)


File: manual.info,  Node: news-5-0-84sp1,  Next: news-5-0-84,  Prev: news-5-0-85,  Up: news-5-0-x

D.1.12 Changes in MySQL Enterprise 5.0.84sp1 [QSP] (30 September 2009)
----------------------------------------------------------------------

This is a _Service Pack_ release of the MySQL Enterprise Server 5.0.

This section documents all changes and bugfixes that have been applied
since the last MySQL Enterprise Server release (5.0.84).

If you would like to receive more fine-grained and personalized _update
alerts_ about fixes that are relevant to the version and features you
use, please consider subscribing to _MySQL Enterprise_ (a commercial
MySQL offering). For more details please see
http://www.mysql.com/products/enterprise/advisors.html.

*Bugs Fixed*

   * *Important Change*: Uninstalling MySQL using the MySQL installer
     on Windows would delete the `my.ini' file. The file is no longer
     deleted. In addition, when a new installation is conducted, any
     existing cofiguration file will be renamed to `myDATETIME.ini.bak'
     during configuration.  (Bug #36493)

   * The server could crash for queries with the following elements: 1.
     An `impossible where' in the outermost `SELECT'; 2. An aggregate
     in the outermost `SELECT'; 3. A correlated subquery with a `WHERE'
     clause that includes an outer field reference as a top-level
     `WHERE' sargable predicate; (Bug #46749)

   * A query containing a subquery in the `FROM' clause and `PROCEDURE
     ANALYSE()' caused a server crash.  (Bug #46184) See also Bug
     #48293.

   * A Windows Installation using the GUI installer would fail with:

          MySQL Server 5.1 Setup Wizard ended prematurely

          The wizard was interrupted before MySQL Server 5.1. could be completely installed.

          Your system has not been modified. To complete installation at another time, please run
          setup again.

          Click Finish to exit the wizard

     This was due to a step in the MSI installer that could fail to
     execute correctly on some environments.  (Bug #45418)


File: manual.info,  Node: news-5-0-84,  Next: news-5-0-83,  Prev: news-5-0-84sp1,  Up: news-5-0-x

D.1.13 Changes in MySQL 5.0.84 (07 July 2009)
---------------------------------------------

This section documents all changes and bugfixes that have been applied
since the last MySQL Enterprise Server and MySQL Community Server
release (5.0.83). If you would like to receive more fine-grained and
personalized _update alerts_ about fixes that are relevant to the
version and features you use, please consider subscribing to _MySQL
Enterprise_ (a commercial MySQL offering). For more details please see
http://www.mysql.com/products/enterprise/advisors.html.

*Bugs Fixed*

   * *Performance*: The `InnoDB' adaptive hash latch is released (if
     held) for several potentially long-running operations. This
     improves throughput for other queries if the current query is
     removing a temporary table, changing a temporary table from memory
     to disk, using *Note `CREATE TABLE ... SELECT': create-table, or
     performing a `MyISAM' repair on a table used within a transaction.
     (Bug #32149)

   * *Security Fix*: A suitable database identifier supplied to the
     `COM_CREATE_DB' or `COM_DROP_DB' command could cause a
     segmentation fault, and thereby a denial of service.  (Bug #45790,
     CVE-2009-2446)

   * *Security Fix*: The server crashed if an account with the `CREATE
     ROUTINE' privilege but not the `EXECUTE' privilege attempted to
     create a stored procedure.  (Bug #44798)

   * *Important Change*: *Replication*: *Note `BEGIN': commit, *Note
     `COMMIT': commit, and *Note `ROLLBACK': commit.  statements are no
     longer affected by `--replicate-do-db' or `--replicate-ignore-db'
     rules.  (Bug #43263)

   * *Replication*: When reading a binary log that was in use by a
     master or that had not been properly closed (possibly due to a
     crash), the following message was printed: `Warning: this binlog
     was not closed properly. Most probably mysqld crashed writing it'.
     This message did not take into account the possibility that the
     file was merely in use by the master, which caused some users
     concern who were not aware that this could happen.

     To make this clear, the original message has been replaced with
     `Warning: this binlog is either is use or was not closed properly'.
     (Bug #34687)

   * The server crashed for attempts to use *Note `REPLACE': replace. or
     *Note `INSERT ... ON DUPLICATE KEY UPDATE': insert. with a view
     defined using a join.  (Bug #45806)

   * The combination of `MIN()' or `MAX()' in the select list with
     `WHERE' and `GROUP BY' clauses could lead to incorrect results.
     (Bug #45386)

   * Compiler warnings on Mac OS X were fixed.  (Bug #45286)

   * The *Note `mysql': mysql. client could misinterpret some character
     sequences as commands under some circumstances.  (Bug #45236)

   * Use of `ROUND()' on a *Note `LONGTEXT': blob. or *Note `LONGBLOB':
     blob. column of a derived table could cause a server crash.  (Bug
     #45152)

   * Index Merge followed by a filesort could result in a server crash
     if `sort_buffer_size' was not large enough for all sort keys.
     (Bug #44810) See also Bug #40974.

   * The `PASSWORD()' and `OLD_PASSWORD()' functions could read memory
     outside of an internal buffer when used with *Note `BLOB': blob.
     arguments.  (Bug #44767)

   * Some Perl scripts in AIX packages contained an incorrect path to
     the `perl' executable.  (Bug #44643)

   * A workaround for a Sun Studio bug was instituted.  (Bug #41710)

   * Shared-memory connections did not work in Vista if *Note `mysqld':
     mysqld. was started from the command line.  (Bug #41190)

   * Some *Note `UPDATE': update. statements that affected no rows
     returned a rows-affected count of one.  (Bug #40565)

   * Valgrind warnings that occurred for *Note `SHOW TABLE STATUS':
     show-table-status. with `InnoDB' tables were silenced.  (Bug
     #38479)

   * In the *Note `mysql': mysql. client, using a default character set
     of `binary' caused internal commands such as `DELIMITER' to become
     case sensitive.  (Bug #37268)

   * A Valgrind error during subquery execution was corrected.  (Bug
     #36995)

   * When invoked to start multiple server instances, *Note
     `mysqld_multi': mysqld-multi. sometimes would fail to start them
     all due to not changing location into the base directory for each
     instance.  (Bug #36654)

   * On Windows, the `_PC' macro in `my_global.h' was causing problems
     for modern compilers. It has been removed because it is no longer
     used.  (Bug #34309)

   * Setting the session value of the `max_allowed_packet' or
     `net_buffer_length' system variable was permitted but had no
     effect. The session value of these variables is now read only.
     (Bug #32223) See also Bug #22891.


File: manual.info,  Node: news-5-0-83,  Next: news-5-0-82sp1,  Prev: news-5-0-84,  Up: news-5-0-x

D.1.14 Changes in MySQL 5.0.83 (29 May 2009)
--------------------------------------------

This section documents all changes and bugfixes that have been applied
since the last MySQL Enterprise Server and MySQL Community Server
release (5.0.82). If you would like to receive more fine-grained and
personalized _update alerts_ about fixes that are relevant to the
version and features you use, please consider subscribing to _MySQL
Enterprise_ (a commercial MySQL offering). For more details please see
http://www.mysql.com/products/enterprise/advisors.html.

*Functionality Added or Changed*

   * The time zone tables available at
     `http://dev.mysql.com/downloads/timezones.html' have been updated.
     These tables can be used on systems such as Windows or HP-UX that
     do not include zoneinfo files.  (Bug #39923)

*Bugs Fixed*

   * *Replication*: When stopping and restarting the slave while it was
     replicating temporary tables, the slave server could crash or
     raise an assertion failure. This was due to the fact that, although
     temporary tables were saved between slave thread restarts, the
     reference to the thread being used (`table->in_use') was not being
     properly updated when restarting, continuing to reference the old
     thread instead of the new one. This issue affected statement-based
     replication only.  (Bug #41725)

   * `UNCOMPRESSED_LENGTH()' returned a garbage result when passed a
     string shorter than 5 bytes. Now `UNCOMPRESSED_LENGTH()' returns
     `NULL' and generates a warning.  (Bug #44796)

   * Several Valgrind warnings were silenced.  (Bug #44774, Bug #44792)

   * Incorrect time was reported at the end of *Note `mysqldump':
     mysqldump. output.  (Bug #44424)

   * *Note `EXPLAIN EXTENDED': explain. could crash for *Note `UNION':
     union. queries in which the last *Note `SELECT': select. was not
     parenthesized and included an `ORDER BY' clause.  (Bug #43612)

   * *Note `SELECT ... INTO @var': select. could produce values
     different from *Note `SELECT ...': select.  without the `INTO'
     clause.  (Bug #42009)

   * Using `--hexdump' together with `--read-from-remote-server' caused
     *Note `mysqlbinlog': mysqlbinlog. to crash.  (Bug #41943)

   * A crash occurred due to a race condition between the merge table
     and `table_cache' evictions.

          00000001403C452F    mysqld.exe!memcpy()[memcpy.asm:151]
          00000001402A275F    mysqld.exe!ha_myisammrg::info()[ha_myisammrg.cc:854]
          00000001402A2471    mysqld.exe!ha_myisammrg::attach_children()[ha_myisammrg.cc:488]
          00000001402A2788    mysqld.exe!ha_myisammrg::extra()[ha_myisammrg.cc:863]
          000000014015FC5D    mysqld.exe!attach_merge_children()[sql_base.cc:4135]
          000000014016A4C1    mysqld.exe!open_tables()[sql_base.cc:4697]
          000000014016A898    mysqld.exe!open_and_lock_tables_derived()[sql_base.cc:4956]
          000000014018BB54    mysqld.exe!mysql_insert()[sql_insert.cc:613]
          000000014019EDD3    mysqld.exe!mysql_execute_command()[sql_parse.cc:3066]
          00000001401A2F06    mysqld.exe!mysql_parse()[sql_parse.cc:5791]
          00000001401A3C1A    mysqld.exe!dispatch_command()[sql_parse.cc:1202]
          00000001401A4CD7    mysqld.exe!do_command()[sql_parse.cc:857]
          0000000140246327    mysqld.exe!handle_one_connection()[sql_connect.cc:1115]
          00000001402B82C5    mysqld.exe!pthread_start()[my_winthread.c:85]
          00000001403CAC37    mysqld.exe!_callthreadstart()[thread.c:295]
          00000001403CAD05    mysqld.exe!_threadstart()[thread.c:275]
          0000000077D6B69A    kernel32.dll!BaseThreadStart()
          Trying to get some variables.
          Some pointers may be invalid and cause the dump to abort...

     (Bug #41212)

   * For some queries, an equality propagation problem could cause `a =
     b' and `b = a' to be handled differently.  (Bug #40925)

   * For views created with a column list clause, column aliases were
     not substituted when selecting through the view using a `HAVING'
     clause.  (Bug #40825)

   * A multiple-table *Note `DELETE': delete. involving a table
     self-join could cause a server crash.  (Bug #39918)

   * Creating an `InnoDB' table with a comment containing a `'#''
     character caused foreign key constraints to be omitted.  (Bug
     #39793)

   * The *Note `mysql': mysql. option `--ignore-spaces' was
     nonfunctional.  (Bug #39101)

   * If a query was such as to produce the error `1054 Unknown column
     '...' in 'field list'', using *Note `EXPLAIN EXTENDED': explain.
     with the query could cause a server crash.  (Bug #37362)


File: manual.info,  Node: news-5-0-82sp1,  Next: news-5-0-82,  Prev: news-5-0-83,  Up: news-5-0-x

D.1.15 Changes in MySQL Enterprise 5.0.82sp1 [QSP] (21 July 2009)
-----------------------------------------------------------------

This is a _Service Pack_ release of the MySQL Enterprise Server 5.0.

This section documents all changes and bugfixes that have been applied
since the last MySQL Enterprise Server release (5.0.82).

If you would like to receive more fine-grained and personalized _update
alerts_ about fixes that are relevant to the version and features you
use, please consider subscribing to _MySQL Enterprise_ (a commercial
MySQL offering). For more details please see
http://www.mysql.com/products/enterprise/advisors.html.

*Bugs Fixed*

   * The server crashed for attempts to use *Note `REPLACE': replace. or
     *Note `INSERT ... ON DUPLICATE KEY UPDATE': insert. with a view
     defined using a join.  (Bug #45806)

   * Use of `ROUND()' on a *Note `LONGTEXT': blob. or *Note `LONGBLOB':
     blob. column of a derived table could cause a server crash.  (Bug
     #45152)

   * Index Merge followed by a filesort could result in a server crash
     if `sort_buffer_size' was not large enough for all sort keys.
     (Bug #44810) See also Bug #40974.

   * If a query was such as to produce the error `1054 Unknown column
     '...' in 'field list'', using *Note `EXPLAIN EXTENDED': explain.
     with the query could cause a server crash.  (Bug #37362)


File: manual.info,  Node: news-5-0-82,  Next: news-5-0-81,  Prev: news-5-0-82sp1,  Up: news-5-0-x

D.1.16 Changes in MySQL 5.0.82 (20 May 2009)
--------------------------------------------

This section documents all changes and bugfixes that have been applied
since the last MySQL Enterprise Server and MySQL Community Server
release (5.0.80). If you would like to receive more fine-grained and
personalized _update alerts_ about fixes that are relevant to the
version and features you use, please consider subscribing to _MySQL
Enterprise_ (a commercial MySQL offering). For more details please see
http://www.mysql.com/products/enterprise/advisors.html.

*Bugs Fixed*

   * *Performance*: *Note `InnoDB': innodb-storage-engine. uses random
     numbers to generate dives into indexes for calculating index
     cardinality.  However, under certain conditions, the algorithm did
     not generate random numbers, so *Note `ANALYZE TABLE':
     analyze-table. did not update cardinality estimates properly. A
     new algorithm has been introduced with better randomization
     properties, together with a system variable,
     `innodb_use_legacy_cardinality_algorithm', that controls which
     algorithm to use. The default value of the variable is 1 (`ON'),
     to use the original algorithm for compatibility with existing
     applications. The variable can be set to 0 (`OFF') to use the new
     algorithm with improved randomness.  (Bug #43660)

   * *Replication*: Restarting the replication slave--either by using
     *Note `STOP SLAVE': stop-slave. plus *Note `START SLAVE':
     start-slave, or by restarting the slave *Note `mysqld': mysqld.
     process--could sometimes cause the slave to crash when using a
     debug version of the server.  (Bug #38694)

   * *Replication*: Killing the thread executing a DDL statement, after
     it had finished its execution but before it had written the binlog
     event, caused the error code in the binlog event to be set
     (incorrectly) to ER_SERVER_SHUTDOWN or ER_QUERY_INTERRUPTED, which
     caused replication to fail.  (Bug #37145) See also Bug #27571, Bug
     #22725.

   * *Replication*: Column aliases used inside subqueries were ignored
     in the binary log.  (Bug #35515)

   * *Replication*: The statements *Note `DROP PROCEDURE IF EXISTS':
     drop-procedure. and *Note `DROP FUNCTION IF EXISTS':
     drop-function. were not written to the binary log if the procedure
     or function to be dropped did not exist.  (Bug #13684) See also
     Bug #25705.

   * Use of *Note `HANDLER': handler. statements with
     `INFORMATION_SCHEMA' tables caused a server crash. Now *Note
     `HANDLER': handler. is prohibited with such tables.  (Bug #44151)

   * *Note `myisamchk': myisamchk. could display a negative `Max
     keyfile length' value.  (Bug #43950)

   * *Note `mysqld_multi': mysqld-multi. incorrectly passed
     `--no-defaults' to *Note `mysqld_safe': mysqld-safe.  (Bug #43876)

   * On Windows, a server crash occurred for attempts to insert a
     floating-point value into a *Note `CHAR': char.  column with a
     maximum length less than the converted floating-point value length.
     (Bug #43833)

   * *Note `UNION': union. of floating-point numbers did unnecessary
     rounding.  (Bug #43432)

   * Certain statements might open a table and then wait for an
     impending global read lock without noticing whether they hold a
     table being waiting for by the global read lock, causing a hang.
     Affected statements are *Note `SELECT ... FOR UPDATE': select,
     *Note `LOCK TABLES ... WRITE': lock-tables, *Note `TRUNCATE
     TABLE': truncate-table, and *Note `LOAD DATA INFILE': load-data.
     (Bug #43230)

   * The `InnoDB' `btr_search_drop_page_hash_when_freed()' function had
     a race condition.  (Bug #42279)

   * Compressing a table with the *Note `myisampack': myisampack.
     utility caused the server to produce Valgrind warnings when it
     opened the table.  (Bug #41541)

   * For a `MyISAM' table with `DELAY_KEY_WRITE' enabled, the index
     file could be corrupted without the table being marked as crashed
     if the server was killed.  (Bug #41330)

   * Multiple-table *Note `UPDATE': update. statements did not properly
     activate triggers.  (Bug #39953)

   * The functions listed in *Note gis-mysql-specific-functions::,
     previously accepted WKB arguments and returned WKB values. They
     now accept WKB or geometry arguments and return geometry values.

     The functions listed in *Note gis-wkb-functions::, previously
     accepted WKB arguments and returned geometry values.  They now
     accept WKB or geometry arguments and return geometry values.  (Bug
     #38990)

   * An *Note `UPDATE': update. statement that updated a column using
     the same `DES_ENCRYPT()' value for each row actually updated
     different rows with different values.  (Bug #35087)

   * For shared-memory connections, the read and write methods did not
     properly handle asynchronous close events, which could lead to the
     client locking up waiting for a server response. For example, a
     call to *Note `mysql_real_query()': mysql-real-query. would block
     forever on the client side if the executed statement was aborted
     on the server side. Thanks to Armin Scho"ffmann for the bug report
     and patch.  (Bug #33899)

   * *Note `CHECKSUM TABLE': checksum-table. was not killable with
     *Note `KILL QUERY': kill.  (Bug #33146)

   * *Note `myisamchk': myisamchk. and *Note `myisampack': myisampack.
     were not being linked with the library that enabled support for
     `*' file name pattern expansion.  (Bug #29248)

   * *Note `COMMIT': commit. did not delete savepoints if there were no
     changes in the transaction.  (Bug #26288)

   * Several memory allocation functions were not being checked for
     out-of-memory return values.  (Bug #25058)


File: manual.info,  Node: news-5-0-81,  Next: news-5-0-80,  Prev: news-5-0-82,  Up: news-5-0-x

D.1.17 Changes in MySQL Community Server 5.0.81 (01 May 2009)
-------------------------------------------------------------

This is a bugfix release for the current MySQL Community Server
production release family. It replaces MySQL 5.0.77.

*Functionality Added or Changed*

   * *Security Enhancement*: To enable stricter control over the
     location from which user-defined functions can be loaded, the
     `plugin_dir' system variable has been backported from MySQL 5.1.
     If the value is nonempty, user-defined function object files can
     be loaded only from the directory named by this variable. If the
     value is empty, the behavior that is used prior to the inclusion of
     `plugin_dir' applies: The UDF object files must be located in a
     directory that is searched by your system's dynamic linker.

     If the plugin directory is writable by the server, it may be
     possible for a user to write executable code to a file in the
     directory using *Note `SELECT ... INTO DUMPFILE': select. This can
     be prevented by making `plugin_dir' read only to the server or by
     setting `--secure-file-priv' to a directory where *Note `SELECT':
     select. writes can be made safely.  (Bug #37428)

   * A new status variable, `Queries', indicates the number of
     statements executed by the server. This includes statements
     executed within stored programs, unlike the `Questions' variable
     which includes only statements sent to the server by clients.
     (Bug #41131)

   * Previously, index hints did not work for `FULLTEXT' searches. Now
     they work as follows:

     For natural language mode searches, index hints are silently
     ignored. For example, `IGNORE INDEX(i)' is ignored with no warning
     and the index is still used.

     For boolean mode searches, index hints are honored.  (Bug #38842)

*Bugs Fixed*

   * *Important Change*: *Security Fix*: Additional corrections were
     made for the symlink-related privilege problem originally
     addressed in MySQL 5.0.60. The original fix did not correctly
     handle the data directory path name if it contained symlinked
     directories in its path, and the check was made only at
     table-creation time, not at table-opening time later.  (Bug
     #32167, CVE-2008-2079) See also Bug #39277.

   * *Security Enhancement*: The server consumed excess memory while
     parsing statements with hundreds or thousands of nested boolean
     conditions (such as `OR (OR ... (OR ... ))'). This could lead to a
     server crash or incorrect statement execution, or cause other
     client statements to fail due to lack of memory. The latter result
     constitutes a denial of service.  (Bug #38296)

   * *Incompatible Change*: There were some problems using `DllMain()'
     hook functions on Windows that automatically do global and
     per-thread initialization for `libmysqld.dll':

        * Per-thread initialization: MySQL internally counts the number
          of active threads, which causes a delay in `my_end()' if not
          all threads have exited. But there are threads that can be
          started either by Windows internally (often in TCP/IP
          scenarios) or by users.  Those threads do not necessarily use
          `libmysql.dll' functionality but still contribute to the
          open-thread count. (One symptom is a five-second delay in
          times for PHP scripts to finish.)

        * Process-initialization: *Note `my_init()': my-init. calls
          `WSAStartup' that itself loads DLLs and can lead to a
          deadlock in the Windows loader.

     To correct these problems, DLL initialization code now is not
     invoked from `libmysql.dll' by default. To obtain the previous
     behavior (DLL initialization code will be called), set the
     `LIBMYSQL_DLLINIT' environment variable to any value. This
     variable exists only to prevent breakage of existing Windows-only
     applications that do not call *Note `mysql_thread_init()':
     mysql-thread-init. and work okay today. Use of `LIBMYSQL_DLLINIT'
     is discouraged and is removed in MySQL 6.0.  (Bug #37226, Bug
     #33031)

   * *Incompatible Change*: *Note `SHOW STATUS': show-status. took a
     lot of CPU time for calculating the value of the
     `Innodb_buffer_pool_pages_latched' status variable. Now this
     variable is calculated and included in the output of *Note `SHOW
     STATUS': show-status. only if the `UNIV_DEBUG' symbol is defined
     at MySQL build time.  (Bug #36600)

   * *Incompatible Change*: In connection with view creation, the
     server created `arc' directories inside database directories and
     maintained useless copies of `.frm' files there. Creation and
     renaming procedures of those copies as well as creation of `arc'
     directories has been discontinued.

     This change does cause a problem when downgrading to older server
     versions which manifests itself under these circumstances:

       1. Create a view `v_orig' in MySQL 5.0.72 or higher.

       2. Rename the view to `v_new' and then back to `v_orig'.

       3. Downgrade to an older 5.0.x server and run *Note
          `mysql_upgrade': mysql-upgrade.

       4. Try to rename `v_orig' to `v_new' again. This operation fails.

     As a workaround to avoid this problem, use either of these
     approaches:

        * Dump your data using *Note `mysqldump': mysqldump. before
          downgrading and reload the dump file after downgrading.

        * Instead of renaming a view after the downgrade, drop it and
          recreate it.

     The downgrade problem introduced by the fix for this bug has been
     addressed as Bug #40021.  (Bug #17823)

   * *Replication*: When rotating relay log files, the slave deletes
     relay log files and then edits the relay log index file. Formerly,
     if the slave shut down unexpectedly between these two events, the
     relay log index file could then reference relay logs that no longer
     existed. Depending on the circumstances, this could when
     restarting the slave cause either a race condition or the failure
     of replication.  (Bug #38826, Bug #39325)

   * In example option files provided in MySQL distributions, the
     `thread_stack' value was increased from 64K to 128K.  (Bug #41577)

   * *Note `SET PASSWORD': set-password. caused a server crash if the
     account name was given as `CURRENT_USER()'.  (Bug #41456)

   * The *Note `INFORMATION_SCHEMA.SCHEMA_PRIVILEGES':
     schema-privileges-table.  table was limited to 7680 rows.  (Bug
     #41079)

   * In debug builds, obsolete debug code could be used to crash the
     server.  (Bug #41041)

   * *Note `CHECK TABLE ... FOR UPGRADE': check-table. did not check
     for incompatible collation changes made in MySQL 5.0.48 (Bug
     #27562, Bug #29461, Bug #29499). This also affects *Note
     `mysqlcheck': mysqlcheck. and *Note `mysql_upgrade':
     mysql-upgrade, which cause that statement to be executed. See
     *Note checking-table-incompatibilities::.  (Bug #40984) See also
     Bug #39585.

   * Some queries that used a `range checked for each record' scan
     could return incorrect results.  (Bug #40974) See also Bug #44810.

   * Certain *Note `SELECT': select. queries could fail with a
     `Duplicate entry' error.  (Bug #40953)

   * The *Note `FEDERATED': federated-storage-engine. handler had a
     memory leak.  (Bug #40875)

   * `IF(..., CAST(LONGTEXT_VAL AS UNSIGNED), SIGNED_VAL)' as an
     argument to an aggregate function could cause an assertion failure.
     (Bug #40761)

   * Prepared statements permitted invalid dates to be inserted when
     the `ALLOW_INVALID_DATES' SQL mode was not enabled.  (Bug #40365)

   * `mc.exe' is no longer needed to compile MySQL on Windows. This
     makes it possible to build MySQL from source using Visual Studio
     Express 2008.  (Bug #40280)

   * Support for the `revision' field in `.frm' files has been removed.
     This addresses the downgrading problem introduced by the fix for
     Bug #17823.  (Bug #40021)

   * If the operating system is configured to return leap seconds from
     OS time calls or if the MySQL server uses a time zone definition
     that has leap seconds, functions such as `NOW()' could return a
     value having a time part that ends with `:59:60' or `:59:61'. If
     such values are inserted into a table, they would be dumped as is
     by *Note `mysqldump': mysqldump. but considered invalid when
     reloaded, leading to backup/restore problems.

     Now leap second values are returned with a time part that ends
     with `:59:59'. This means that a function such as `NOW()' can
     return the same value for two or three consecutive seconds during
     the leap second. It remains true that literal temporal values
     having a time part that ends with `:59:60' or `:59:61' are
     considered invalid.

     For additional details about leap-second handling, see *Note
     time-zone-leap-seconds::.  (Bug #39920)

   * The server could crash during a sort-order optimization of a
     dependent subquery.  (Bug #39844)

   * With the `ONLY_FULL_GROUP_BY' SQL mode enabled, the check for
     nonaggregated columns in queries with aggregate functions, but
     without a `GROUP BY' clause was treating all the parts of the
     query as if they were in the select list. This is fixed by
     ignoring the nonaggregated columns in the `WHERE' clause.  (Bug
     #39656)

   * The server crashed if an integer field in a CSV file did not have
     delimiting quotation marks.  (Bug #39616)

   * Creating a table with a comment of 62 characters or longer caused
     a server crash.  (Bug #39591)

   * *Note `CHECK TABLE': check-table. failed for *Note `MyISAM':
     myisam-storage-engine.  `INFORMATION_SCHEMA' tables.  (Bug #39541)

   * `InnoDB' could hang trying to open an adaptive hash index.  (Bug
     #39483)

   * For a *Note `TIMESTAMP': datetime. column in an `InnoDB' table,
     testing the column with multiple conditions in the `WHERE' clause
     caused a server crash.  (Bug #39353)

   * The server returned a column type of *Note `VARBINARY':
     binary-varbinary. rather than *Note `DATE': datetime. as the
     result from the `COALESCE()', `IFNULL()', `IF()', `GREATEST()', or
     `LEAST()' functions or `CASE' expression if the result was
     obtained using `filesort' in an anonymous temporary table during
     the query execution.  (Bug #39283)

   * References to local variables in stored procedures are replaced
     with `NAME_CONST(NAME, VALUE)' when written to the binary log.
     However, an `illegal mix of collation' error might occur when
     executing the log contents if the value's collation differed from
     that of the variable. Now information about the variable collation
     is written as well.  (Bug #39182)

   * Some recent releases for Solaris 10 were built on Solaris 10 U5,
     which included a new version of `libnsl.so' that does not work on
     U4 or earlier. To correct this, Solaris 10 builds now are created
     on machines that do not have that upgraded `libnsl.so', so that
     they will work on Solaris 10 installations both with and without
     the upgraded `libnsl.so'.  (Bug #39074)

   * With binary logging enabled *Note `CREATE VIEW': create-view. was
     subject to possible buffer overwrite and a server crash.  (Bug
     #39040)

   * Queries of the form `SELECT ... REGEXP BINARY NULL' could lead to
     a hung or crashed server.  (Bug #39021)

   * Statements of the form `INSERT ... SELECT .. ON DUPLICATE KEY
     UPDATE COL_NAME = DEFAULT' could result in a server crash.  (Bug
     #39002)

   * Column names constructed due to wild-card expansion done inside a
     stored procedure could point to freed memory if the expansion was
     performed after the first call to the stored procedure.  (Bug
     #38823)

   * Repeated *Note `CREATE TABLE ... SELECT': create-table.
     statements, where the created table contained an `AUTO_INCREMENT'
     column, could lead to an assertion failure.  (Bug #38821)

   * If delayed insert failed to upgrade the lock, it did not free the
     temporary memory storage used to keep newly constructed *Note
     `BLOB': blob. values in memory, resulting in a memory leak.  (Bug
     #38693)

   * A server crash resulted from concurrent execution of a
     multiple-table *Note `UPDATE': update. that used a `NATURAL' or
     `USING' join together with *Note `FLUSH TABLES WITH READ LOCK':
     flush. or *Note `ALTER TABLE': alter-table. for the table being
     updated.  (Bug #38691)

   * On ActiveState Perl, `mysql-test-run.pl --start-and-exit' started
     but did not exit.  (Bug #38629)

   * Server-side cursors were not initialized properly, which could
     cause a server crash.  (Bug #38486)

   * Stored procedures involving substrings could crash the server on
     certain platforms due to invalid memory reads.  (Bug #38469)

   * A server crash or Valgrind warnings could result when a stored
     procedure selected from a view that referenced a function.  (Bug
     #38291)

   * Incorrect handling of aggregate functions when loose index scan
     was used caused a server crash.  (Bug #38195)

   * Queries containing a subquery with `DISTINCT' and `ORDER BY' could
     cause a server crash.  (Bug #38191)

   * Queries with a `HAVING' clause could return a spurious row.  (Bug
     #38072)

   * Use of spatial data types in prepared statements could cause
     memory leaks or server crashes.  (Bug #37956, Bug #37671)

   * The server crashed if an argument to a stored procedure was a
     subquery that returned more than one row.  (Bug #37949)

   * When analyzing the possible index use cases, the server was
     incorrectly reusing an internal structure, leading to a server
     crash.  (Bug #37943)

   * A *Note `SELECT': select. with a `NULL NOT IN' condition
     containing a complex subquery from the same table as in the outer
     select caused an assertion failure.  (Bug #37894)

   * For `InnoDB' tables, `ORDER BY ...  DESC' sometimes returned
     results in ascending order.  (Bug #37830)

   * If a table has a `BIT NOT NULL' column `c1' with a length shorter
     than 8 bits and some additional `NOT NULL' columns `c2', ..., and a
     *Note `SELECT': select. query has a `WHERE' clause of the form
     `(c1 = CONSTANT) AND c2 ...', the query could return an unexpected
     result set.  (Bug #37799)

   * Nesting of `IF()' inside of `SUM()' could cause an extreme server
     slowdown.  (Bug #37662)

   * The `MONTHNAME()' and `DAYNAME()' functions returned a binary
     string, so that using `LOWER()' or `UPPER()' had no effect. Now
     `MONTHNAME()' and `DAYNAME()' return a value in
     `character_set_connection' character set.  (Bug #37575)

   * `TIMEDIFF()' was erroneously treated as always returning a
     positive result. Also, `CAST()' of *Note `TIME': time. values to
     *Note `DECIMAL': numeric-types. dropped the sign of negative
     values.  (Bug #37553) See also Bug #42525.

   * *Note `mysqlcheck': mysqlcheck. used *Note `SHOW FULL TABLES':
     show-tables. to get the list of tables in a database. For some
     problems, such as an empty `.frm' file for a table, this would
     fail and *Note `mysqlcheck': mysqlcheck.  then would neglect to
     check other tables in the database.  (Bug #37527)

   * The `<=>' operator could return incorrect results when comparing
     `NULL' to *Note `DATE': datetime, *Note `TIME': time, or *Note
     `DATETIME': datetime. values.  (Bug #37526)

   * Updating a view with a subquery in the `CHECK' option could cause
     an assertion failure.  (Bug #37460)

   * Statements that displayed the value of system variables (for
     example, *Note `SHOW VARIABLES': show-variables.) expect variable
     values to be encoded in `character_set_system'. However, variables
     set from the command line such as `basedir' or `datadir' were
     encoded using `character_set_filesystem' and not converted
     correctly.  (Bug #37339)

   * For a `MyISAM' table with `CHECKSUM = 1' and `ROW_FORMAT =
     DYNAMIC' table options, a data consistency check (maximum record
     length) could fail and cause the table to be marked as corrupted.
     (Bug #37310)

   * The `max_length' result set metadata value was calculated
     incorrectly under some circumstances.  (Bug #37301)

   * *Note `CREATE INDEX': create-index. could crash with `InnoDB'
     plugin 1.0.1.  (Bug #37284)

   * Certain boolean-mode `FULLTEXT' searches that used the truncation
     operator did not return matching records and calculated relevance
     incorrectly.  (Bug #37245)

   * The `NO_BACKSLASH_ESCAPES' SQL mode was ignored for *Note `LOAD
     DATA INFILE': load-data. and `SELECT INTO ... OUTFILE'.  The
     setting is taken into account now.  (Bug #37114)

   * On a 32-bit server built without big tables support, the offset
     argument in a `LIMIT' clause might be truncated due to a 64-bit to
     32-bit cast.  (Bug #37075)

   * If the server failed to expire binary log files at startup, it
     could crash.  (Bug #37027)

   * The code for the `ut_usectime()' function in `InnoDB' did not
     handle errors from the `gettimeofday()' system call. Now it retries
     `gettimeofday()' several times and updates the value of the
     `Innodb_row_lock_time_max' status variable only if `ut_usectime()'
     was successful.  (Bug #36819)

   * Use of `CONVERT()' with `GROUP BY' to convert numeric values to
     *Note `CHAR': char. could return truncated results.  (Bug #36772)

   * A query which had an `ORDER BY DESC' clause that is satisfied with
     a reverse range scan could cause a server crash for some specific
     CPU/compiler combinations.  (Bug #36639)

   * Dumping information about locks in use by sending a `SIGHUP'
     signal to the server or by invoking the *Note `mysqladmin debug':
     mysqladmin. command could lead to a server crash in debug builds
     or to undefined behavior in production builds.  (Bug #36579)

   * The *Note `mysql': mysql. client, when built with Visual Studio
     2005, did not display Japanese characters.  (Bug #36279)

   * When the fractional part in a multiplication of *Note `DECIMAL':
     numeric-types. values overflowed, the server truncated the first
     operand rather than the longest. Now the server truncates so as to
     produce more precise multiplications.  (Bug #36270)

   * A read past the end of the string could occur while parsing the
     value of the `--innodb-data-file-path' option.  (Bug #36149)

   * Host name values in SQL statements were not being checked for
     `'@'', which is illegal according to RFC952.  (Bug #35924)

   * The `UUID()' function returned UUIDs with the wrong time; this was
     because the offset for the time part in UUIDs was miscalculated.
     (Bug #35848)

   * *Note `SHOW CREATE TABLE': show-create-table. did not display a
     printable value for the default value of *Note `BIT':
     numeric-types. columns.  (Bug #35796)

   * *Note `mysql_install_db': mysql-install-db. failed on machines
     that had the host name set to `localhost'.  (Bug #35754)

   * Dynamic plugins failed to load on i5/OS.  (Bug #35743)

   * Freeing of an internal parser stack during parsing of complex
     stored programs caused a server crash.  (Bug #35577, Bug #37269,
     Bug #37228)

   * The `max_length' metadata value was calculated incorrectly for the
     `FORMAT()' function, which could cause incorrect result set
     metadata to be sent to clients.  (Bug #35558)

   * Index scans performed with the `sort_union()' access method
     returned wrong results, caused memory to be leaked, and caused
     temporary files to be deleted when the limit set by
     `sort_buffer_size' was reached.  (Bug #35477, Bug #35478)

   * If the server crashed with an `InnoDB' error due to unavailability
     of undo slots, errors could persist during rollback when the
     server was restarted: There are two `UNDO' slot caches (for *Note
     `INSERT': insert. and *Note `UPDATE': update.). If all slots end
     up in one of the slot caches, a request for a slot from the other
     slot cache would fail. This can happen if the request is for an
     *Note `UPDATE': update. slot and all slots are in the *Note
     `INSERT': insert. slot cache, or vice versa.  (Bug #35352)

   * For `InnoDB' tables, `ALTER TABLE DROP' failed if the name of the
     column to be dropped began with `foreign'.  (Bug #35220)

   * *Note `perror': perror. on Windows did not know about Win32 system
     error codes.  (Bug #34825)

   * *Note `EXPLAIN EXTENDED': explain. evaluation of aggregate
     functions that required a temporary table caused a server crash.
     (Bug #34773)

   * Queries of the form `SELECT ... WHERE STRING = ANY(...)' failed
     when the server used a single-byte character set and the client
     used a multi-byte character set.  (Bug #34760) See also Bug #20835.

   * Using *Note `OPTIMIZE TABLE': optimize-table. as the first
     statement on an `InnoDB' table with an `AUTO_INCREMENT' column
     could cause a server crash.  (Bug #34286)

   * *Note `mysql_install_db': mysql-install-db. failed if the server
     was running with an SQL mode of `TRADITIONAL'. This program now
     resets the SQL mode internally to avoid this problem.  (Bug #34159)

   * Changes to build files were made to enable the MySQL distribution
     to compile on Microsoft Visual C++ Express 2008.  (Bug #33907)

   * The *Note `mysql': mysql. client incorrectly parsed statements
     containing the word `delimiter' in mid-statement.

     This fix is different from the one applied for this bug in MySQL
     5.0.66.  (Bug #33812) See also Bug #38158.

   * For a stored procedure containing a `SELECT * ... RIGHT JOIN'
     query, execution failed for the second call.  (Bug #33811)

   * Previously, use of index hints with views (which do not have
     indexes) produced the error `ERROR 1221 (HY000): Incorrect usage
     of USE/IGNORE INDEX and VIEW'. Now this produces `ERROR 1176
     (HY000): Key '...' doesn't exist in table '...'', the same error
     as for base tables without an appropriate index.  (Bug #33461)

   * Cached queries that used 256 or more tables were not properly
     cached, so that later query invalidation due to a *Note `TRUNCATE
     TABLE': truncate-table. for one of the tables caused the server to
     hang.  (Bug #33362)

   * Some division operations produced a result with incorrect
     precision.  (Bug #31616)

   * *Note `mysql_upgrade': mysql-upgrade. attempted to use the `/proc'
     file system even on systems that do not have it.  (Bug #31605)

   * *Note `mysqldump': mysqldump. could fail to dump views containing
     a large number of columns.  (Bug #31434)

   * Queries executed using join buffering of *Note `BIT':
     numeric-types. columns could produce incorrect results.  (Bug
     #31399)

   * `ALTER TABLE CONVERT TO CHARACTER SET' did not convert *Note
     `TINYTEXT': blob. or *Note `MEDIUMTEXT': blob. columns to a longer
     text type if necessary when converting the column to a different
     character set.  (Bug #31291)

   * For installation on Solaris using `pkgadd' packages, the *Note
     `mysql_install_db': mysql-install-db. script was generated in the
     `scripts' directory, but the temporary files used during the
     process were left there and not deleted.  (Bug #31052)

   * Several MySQL programs could fail if the `HOME' environment
     variable had an empty value.  (Bug #30394)

   * On NetWare, *Note `mysql_install_db': mysql-install-db. could
     appear to execute normally even if it failed to create the initial
     databases.  (Bug #30129)

   * The Serbian translation for the `ER_INCORRECT_GLOBAL_LOCAL_VAR'
     error was corrected.  (Bug #29738)

   * XA transaction rollbacks could result in corrupted transaction
     states and a server crash.  (Bug #28323)

   * The `BUILD/check-cpu' build script failed if `gcc' had a different
     name (such as `gcc.real' on Debian).  (Bug #27526)

   * On Windows, Visual Studio does not take into account some x86
     hardware limitations, which led to incorrect results converting
     large *Note `DOUBLE': numeric-types. values to unsigned *Note
     `BIGINT': numeric-types. values.  (Bug #27483)

   * SSL support was not included in some `generic' RPM packages.  (Bug
     #26760)

   * In some cases, the parser interpreted the `;' character as the end
     of input and misinterpreted stored program definitions.  (Bug
     #26030)

   * The `Questions' status variable is intended as a count of
     statements sent by clients to the server, but was also counting
     statements executed within stored routines.  (Bug #24289)

   * For access to the *Note `INFORMATION_SCHEMA.VIEWS': views-table.
     table, the server did not check the `SHOW VIEW' and *Note
     `SELECT': select.  privileges, leading to inconsistency between
     output from that table and the *Note `SHOW CREATE VIEW':
     show-create-view.  statement.  (Bug #22763)

   * The *Note `FLUSH PRIVILEGES': flush. statement did not produce an
     error when it failed.  (Bug #21226)

   * A race condition between the *Note `mysqld.exe': mysqld.  server
     and the Windows service manager could lead to inability to stop
     the server from the service manager.  (Bug #20430)

   * `mysqld_safe' would sometimes fail to remove the pid file for the
     old `mysql' process after a crash. As a result, the server would
     fail to start due to a false `A mysqld process already exists...'
     error.  (Bug #11122)


File: manual.info,  Node: news-5-0-80,  Next: news-5-0-79,  Prev: news-5-0-81,  Up: news-5-0-x

D.1.18 Changes in MySQL Enterprise 5.0.80 [MRU] (01 May 2009)
-------------------------------------------------------------

This is a _Monthly Rapid Update_ release of the MySQL Enterprise Server
5.0.

This section documents all changes and bugfixes that have been applied
since the last MySQL Enterprise Server release (5.0.79).  If you would
like to receive more fine-grained and personalized _update alerts_
about fixes that are relevant to the version and features you use,
please consider subscribing to _MySQL Enterprise_ (a commercial MySQL
offering). For more details please see
http://www.mysql.com/products/enterprise/advisors.html.

Support Ending for AIX 5.2: Per the
http://www.mysql.com/about/legal/lifecycle/ regarding ending support
for OS versions that have reached vendor end of life, we plan to
discontinue building or supporting MySQL binaries for AIX 5.2 as of
April 30, 2009. This release of MySQL 5.0 (5.0.80) is the last MySQL
5.0 release with support for AIX 5.2. For more information, see the
March 24, 2009 note at MySQL Product Support EOL Announcements
(http://dev.mysql.com/support/eol-notice.html).

*Functionality Added or Changed*

   * The MD5 algorithm now uses the Xfree implementation.  (Bug #42434)

*Bugs Fixed*

   * *Replication*: An *Note `INSERT DELAYED': insert. into a *Note
     `TIMESTAMP': datetime. column issued concurrently with an insert
     on the same column not using `DELAYED', but applied after the
     other insert, was logged using the same timestamp as generated by
     the other (non-`DELAYED') insert.  (Bug #41719)

   * An attempt by a user who did not have the `SUPER' privilege to
     kill a system thread could cause a server crash.  (Bug #43748)

   * Use of `USE INDEX' hints could cause *Note `EXPLAIN EXTENDED':
     explain. to crash.  (Bug #43354)

   * *Note `mysql': mysql. crashed if a request for the current
     database name returned an empty result, such as after the client
     has executed a preceding `SET sql_select_limit=0' statement.  (Bug
     #43254)

   * The `strings/CHARSET_INFO.txt' file was not included in source
     distributions.  (Bug #42937)

   * *Note `mysqldump': mysqldump. included views that were excluded
     with the `--ignore-table' option.  (Bug #42635)

   * Passing an unknown time zone specification to `CONVERT_TZ()'
     resulted in a memory leak.  (Bug #42502)

   * The MySQL Instance Configuration Wizard would fail to start
     correctly on Windows Vista.  (Bug #42386)

   * With more than two arguments, `LEAST()', `GREATEST()', and `CASE'
     could unnecessarily return `Illegal mix of collations' errors.
     (Bug #41627)

   * The *Note `mysql': mysql. client could misinterpret its input if a
     line was longer than an internal buffer.  (Bug #41486)

   * In the `help' command output displayed by *Note `mysql': mysql,
     the description for the `\c' (`clear') command was misleading.
     (Bug #41268)

   * When running the MySQL Instance Configuration Wizard in
     command-line only mode, the service name would be ignored
     (effectively creating all instances with the default `MySQL'
     service name), irrespective of the name specified on the command
     line. However, the wizard would attempt to start the service with
     the specified name, and would fail.  (Bug #38379)

   * The use of `NAME_CONST()' can result in a problem for *Note
     `CREATE TABLE ... SELECT': create-table. statements when the
     source column expressions refer to local variables. Converting
     these references to `NAME_CONST()' expressions can result in
     column names that are different on the master and slave servers,
     or names that are too long to be legal column identifiers. A
     workaround is to supply aliases for columns that refer to local
     variables.

     Now a warning is issued in such cases that indicate possible
     problems.  (Bug #35383)

   * *Note `CHECK TABLE': check-table, *Note `REPAIR TABLE':
     repair-table, *Note `ANALYZE TABLE': analyze-table, and *Note
     `OPTIMIZE TABLE': optimize-table. erroneously reported a table to
     be corrupt if the table did not exist or the statement was
     terminated with *Note `KILL': kill.  (Bug #29458)

   * The `Time' column for *Note `SHOW PROCESSLIST': show-processlist.
     output now can have negative values.  Previously, the column was
     unsigned and negative values were displayed incorrectly as large
     positive values. Negative values can occur if a thread alters the
     time into the future with *Note `SET TIMESTAMP = VALUE':
     set-option. or the thread is executing on a slave and processing
     events from a master that has its clock set ahead of the slave.
     (Bug #22047)

   * Restoring a *Note `mysqldump': mysqldump. dump file containing
     `FEDERATED' tables failed because the file contained the data for
     the table. Now only the table definition is dumped (because the
     data is located elsewhere).  (Bug #21360)


File: manual.info,  Node: news-5-0-79,  Next: news-5-0-78,  Prev: news-5-0-80,  Up: news-5-0-x

D.1.19 Changes in MySQL Enterprise 5.0.79 [MRU] (09 March 2009)
---------------------------------------------------------------

This is a _Monthly Rapid Update_ release of the MySQL Enterprise Server
5.0.

This section documents all changes and bugfixes that have been applied
since the last MySQL Enterprise Server release (5.0.78).  If you would
like to receive more fine-grained and personalized _update alerts_
about fixes that are relevant to the version and features you use,
please consider subscribing to _MySQL Enterprise_ (a commercial MySQL
offering). For more details please see
http://www.mysql.com/products/enterprise/advisors.html.

*Functionality Added or Changed*

   * *Performance*: The query cache now checks whether a *Note
     `SELECT': select. statement begins with `SQL_NO_CACHE' to
     determine whether it can skip checking for the query result in the
     query cache. This is not supported when `SQL_NO_CACHE' occurs
     within a comment.  (Bug #37416)

   * The `libedit' library was upgraded to version 2.11.  (Bug #42433)

*Bugs Fixed*

   * *Performance*: For an `InnoDB' table, *Note `DROP TABLE':
     drop-table. or *Note `ALTER TABLE ... DISCARD TABLESPACE':
     alter-table. could take a long time or cause a server crash.  (Bug
     #39939)

   * *Replication*: Server IDs greater than 2147483647 (2^32 - 1) were
     represented by negative numbers in the binary log.  (Bug #37313)

   * *Replication*: The `--replicate-*-table' options were not
     evaluated correctly when replicating multi-table updates.

     As a result of this fix, replication of multi-table updates no
     longer fails when an update references a missing table but does
     not update any of its columns.  (Bug #37051)

   * *Replication*: When its disk becomes full, a replication slave may
     wait while writing the binary log, relay log or *Note `MyISAM':
     myisam-storage-engine. tables, continuing after space has been
     made available. The error message provided in such cases was not
     clear about the frequency with which checking for free space is
     done (once every 60 seconds), and how long the server waits after
     space has been freed before continuing (also 60 seconds); this
     caused users to think that the server had hung.

     These issues have been addressed by making the error message
     clearer, and dividing it into two separate messages:

       1. The error message `Disk is full writing 'FILENAME' (Errcode:
          ERROR_CODE). Waiting for someone to free space... (Expect up
          to 60 secs delay for server to continue after freeing disk
          space)' is printed only once.

       2. The warning `Retry in 60 secs, Message reprinted in 600 secs'
          is printed once every for every 10 times that the check for
          free space is made; that is, the check is performed once each
          60 seconds, but the reminder that space needs to be freed is
          printed only once every 10 minutes (600 seconds).

     (Bug #22082)

   * On 32-bit Windows, *Note `mysqld': mysqld. could not use large
     buffers due to a 2GB user mode address limit.  (Bug #43082)

   * The use by `libedit' of the `__weak_reference()' macro caused
     compilation failure on FreeBSD.  (Bug #42817)

   * Tables could enter open table cache for a thread without being
     properly cleaned up, leading to a server crash.  (Bug #42419)

   * *Note `mysqldumpslow': mysqldumpslow. parsed the `--debug' and
     `--verbose' options incorrectly.  (Bug #42027)

   * String reallocation could cause memory overruns.  (Bug #41868)

   * Queries that used the loose index scan access method could return
     no rows.  (Bug #41610)

   * In `InnoDB' recovery after a server crash, rollback of a
     transaction that updated a column from `NULL' to `NULL' could cause
     another crash.  (Bug #41571)

   * If `InnoDB' reached its limit on the number of concurrent
     transactions (1023), it wrote a descriptive message to the error
     log but returned a misleading error message to the client, or an
     assertion failure occurred.  (Bug #41529)

   * Use of `SELECT *' permitted users with rights to only some columns
     of a view to access all columns.  (Bug #41354)

   * The server did not robustly handle problems hang if a table opened
     with *Note `HANDLER': handler. needed to be re-opened because it
     had been altered to use a different storage engine that does not
     support *Note `HANDLER': handler. The server also failed to set an
     error if the re-open attempt failed. These problems could cause
     the server to crash or hang.  (Bug #41110, Bug #41112)

   * For prepared statements, multibyte character sets were not taking
     into account when calculating `max_length' for string values and
     *Note `mysql_stmt_fetch()': mysql-stmt-fetch. could return
     truncated strings.  (Bug #41078)

   * The *Note `mysql_change_user()': mysql-change-user. C API function
     changed the value of the `sql_big_selects' session variable.  (Bug
     #40363) See also Bug #20023.

   * For a view that references a table in another database, *Note
     `mysqldump': mysqldump. wrote the view name qualified with the
     current database name. This makes it impossible to reload the dump
     file into a different database.  (Bug #40345)

   * *Note `perror': perror. did not produce correct output for error
     codes 153 to 163.  (Bug #39370)

   * Comparisons between row constructors, such as `(a, b) = (c, d)'
     resulted in unnecessary `Illegal mix of collations' errors for
     string columns.  (Bug #37601)

   * An argument to the `MATCH()' function that was an alias for an
     expression other than a column name caused a server crash.  (Bug
     #36737)

   * For *Note `DROP FUNCTION': drop-function. with names that were
     qualified with a database name, the database name was handled in
     case-sensitive fashion even with `lower_case_table_names' set to 1.
     (Bug #33813)

   * *Note `mysqldump --compatible=mysql40': mysqldump. emitted
     statements referring to the `character_set_client' system
     variable, which is unknown before MySQL 4.1. Now the statements
     are enclosed in version-specific comments.  (Bug #33550)

   * Use of MBR spatial functions such as `MBRTouches()' with columns of
     `InnoDB' tables caused a server crash rather than an error.  (Bug
     #31435)

   * The *Note `mysql': mysql. client mishandled input parsing if a
     `delimiter' command was not first on the line.  (Bug #31060)

   * For installation on Solaris using `pkgadd' packages, the *Note
     `mysql_install_db': mysql-install-db. script was generated in the
     `scripts' directory, but the temporary files used during the
     process were left there and not deleted.  (Bug #31052)

   * *Note `SHOW PRIVILEGES': show-privileges. listed the `CREATE
     ROUTINE' privilege as having a context of `Functions,Procedures',
     but it is a database-level privilege.  (Bug #30305)

   * *Note `SHOW TABLE STATUS': show-table-status. could fail to
     produce output for tables with non-ASCII characters in their name.
     (Bug #25830)

   * Floating-point numbers could be handled with different numbers of
     digits depending on whether the text or prepared-statement
     protocol was used.  (Bug #21205)

   * Incorrect length metadata could be returned for `LONG TEXT'
     columns when a multibyte server character set was used.  (Bug
     #19829)

   * `ROUND()' sometimes returned different results on different
     platforms.  (Bug #15936)


File: manual.info,  Node: news-5-0-78,  Next: news-5-0-77,  Prev: news-5-0-79,  Up: news-5-0-x

D.1.20 Changes in MySQL Enterprise 5.0.78 [MRU] (06 February 2009)
------------------------------------------------------------------

This is a _Monthly Rapid Update_ release of the MySQL Enterprise Server
5.0.

This section documents all changes and bugfixes that have been applied
since the last MySQL Enterprise Server release (5.0.76).  If you would
like to receive more fine-grained and personalized _update alerts_
about fixes that are relevant to the version and features you use,
please consider subscribing to _MySQL Enterprise_ (a commercial MySQL
offering). For more details please see
http://www.mysql.com/products/enterprise/advisors.html.

*Bugs Fixed*

   * *Important Change*: When installing MySQL on Windows, it was
     possible to install multiple editions (Complete, and Essential,
     for example) of the same version of MySQL, leading to two separate
     entries in the installed packages which were impossible to
     isolate. This could lead to problems with installation and
     uninstallation. The MySQL installer on Windows no longers permits
     multiple installations of the same version of MySQL on a single
     machine.  (Bug #4217)

   * *MySQL Cluster*: *Packaging*: Packages for MySQL Cluster were
     missing the `libndbclient.so' and `libndbclient.a' files.  (Bug
     #42278)

   * An optimization introduced for Bug #37553 required an explicit
     cast to be added for some uses of `TIMEDIFF()' because automatic
     casting could produce incorrect results. (It was necessary to use
     `TIME(TIMEDIFF(...))'.)  (Bug #42525)

   * The SSL certficates included with MySQL distributions were
     regenerated because the previous ones had expired.  (Bug #42366)

   * Dependent subqueries such as the following caused a memory leak
     proportional to the number of outer rows:

          SELECT COUNT(*) FROM t1, t2 WHERE t2.b
            IN (SELECT DISTINCT t2.b FROM t2 WHERE t2.b = t1.a);

     (Bug #42037)

   * Some queries using `NAME_CONST(.. COLLATE ...)' led to a server
     crash due to a failed type cast.  (Bug #42014)

   * On Mac OS X, some of the universal client libraries were not
     actually universal and were missing code for one or more
     architectures.  (Bug #41940)

   * `DATE_FORMAT()' could cause a server crash for year-zero dates.
     (Bug #41470)

   * When substituting system constant functions with a constant
     result, the server was not expecting `NULL' function return values
     and could crash.  (Bug #41437)

   * For a *Note `TIMESTAMP NOT NULL DEFAULT ...': datetime. column,
     storing `NULL' as the return value from some functions caused a
     `cannot be NULL' error.  `NULL' returns now correctly cause the
     column default value to be stored.  (Bug #41370)

   * The Windows installer displayed incorrect product names in some
     images.  (Bug #40845)

   * The query cache stored only partial query results if a statement
     failed while the results were being sent to the client. This could
     cause other clients to hang when trying to read the cached result.
     Now if a statement fails, the result is not cached.  (Bug #40264)

   * The expression `ROW(...) IN (SELECT ... FROM DUAL)' always
     returned `TRUE'.  (Bug #39069)

   * The greedy optimizer could cause a server crash due to improper
     handling of nested outer joins.  (Bug #38795)

   * Use of `COUNT(DISTINCT)' prevented `NULL' testing in the `HAVING'
     clause.  (Bug #38637)

   * Enabling the `sync_frm' system variable had no effect on the
     handling of `.frm' files for views.  (Bug #38145)

   * The query cache stored packets containing the server status of the
     time when the cached statement was run. This might lead to an
     incorrect transaction status on the client side if a statement was
     cached during a transaction and later served outside a transaction
     context (or vice versa).  (Bug #36326)

   * If the system time was adjusted backward during query execution,
     the apparent execution time could be negative. But in some cases
     these queries would be written to the slow query log, with the
     negative execution time written as a large unsigned number. Now
     statements with apparent negative execution time are not written
     to the slow query log.  (Bug #35396)

   * For *Note `mysqld_multi': mysqld-multi, using the
     `--mysqld=mysqld_safe' option caused the `--defaults-file' and
     `--defaults-extra-file' options to behave the same way.  (Bug
     #32136)

   * Attempts to open a valid *Note `MERGE': merge-storage-engine.
     table sometimes resulted in a `ER_WRONG_MRG_TABLE' error. This
     happened after failure to open an invalid *Note `MERGE':
     merge-storage-engine. table had also generated an
     `ER_WRONG_MRG_TABLE' error.  (Bug #32047)

   * The *Note `mysql_change_user()': mysql-change-user. C API function
     caused global `Com_XXX' status variable values to be incorrect.
     (Bug #31222)

   * For Solaris package installation using `pkgadd', the postinstall
     script failed, causing the system tables in the `mysql' database
     not to be created.  (Bug #31164)

   * When installing the Windows service, using quotation marks around
     command-line configuration parameters could cause the quotation
     marks to be incorrectly placed around the entire command-line
     option, and not just the value.  (Bug #27535)


File: manual.info,  Node: news-5-0-77,  Next: news-5-0-76,  Prev: news-5-0-78,  Up: news-5-0-x

D.1.21 Changes in MySQL Community Server 5.0.77 (28 January 2009)
-----------------------------------------------------------------

This is a bugfix release for the current MySQL Community Server
production release family. It replaces MySQL 5.0.67 (binary) and 5.0.75
(source-only).

*Functionality Added or Changed*

   * *Security Enhancement*: To enable stricter control over the
     location from which user-defined functions can be loaded, the
     `plugin_dir' system variable has been backported from MySQL 5.1.
     If the value is nonempty, user-defined function object files can
     be loaded only from the directory named by this variable. If the
     value is empty, the behavior that is used prior to the inclusion of
     `plugin_dir' applies: The UDF object files must be located in a
     directory that is searched by your system's dynamic linker.

     If the plugin directory is writable by the server, it may be
     possible for a user to write executable code to a file in the
     directory using *Note `SELECT ... INTO DUMPFILE': select. This can
     be prevented by making `plugin_dir' read only to the server or by
     setting `--secure-file-priv' to a directory where *Note `SELECT':
     select. writes can be made safely.  (Bug #37428)

   * A new status variable, `Queries', indicates the number of
     statements executed by the server. This includes statements
     executed within stored programs, unlike the `Questions' variable
     which includes only statements sent to the server by clients.
     (Bug #41131)

   * Previously, index hints did not work for `FULLTEXT' searches. Now
     they work as follows:

     For natural language mode searches, index hints are silently
     ignored. For example, `IGNORE INDEX(i)' is ignored with no warning
     and the index is still used.

     For boolean mode searches, index hints are honored.  (Bug #38842)

*Bugs Fixed*

   * *Important Change*: *Security Fix*: Additional corrections were
     made for the symlink-related privilege problem originally
     addressed in MySQL 5.0.60. The original fix did not correctly
     handle the data directory path name if it contained symlinked
     directories in its path, and the check was made only at
     table-creation time, not at table-opening time later.  (Bug
     #32167, CVE-2008-2079) See also Bug #39277.

   * *Security Enhancement*: The server consumed excess memory while
     parsing statements with hundreds or thousands of nested boolean
     conditions (such as `OR (OR ... (OR ... ))'). This could lead to a
     server crash or incorrect statement execution, or cause other
     client statements to fail due to lack of memory. The latter result
     constitutes a denial of service.  (Bug #38296)

   * *Incompatible Change*: There were some problems using `DllMain()'
     hook functions on Windows that automatically do global and
     per-thread initialization for `libmysqld.dll':

        * Per-thread initialization: MySQL internally counts the number
          of active threads, which causes a delay in `my_end()' if not
          all threads have exited. But there are threads that can be
          started either by Windows internally (often in TCP/IP
          scenarios) or by users.  Those threads do not necessarily use
          `libmysql.dll' functionality but still contribute to the
          open-thread count. (One symptom is a five-second delay in
          times for PHP scripts to finish.)

        * Process-initialization: *Note `my_init()': my-init. calls
          `WSAStartup' that itself loads DLLs and can lead to a
          deadlock in the Windows loader.

     To correct these problems, DLL initialization code now is not
     invoked from `libmysql.dll' by default. To obtain the previous
     behavior (DLL initialization code will be called), set the
     `LIBMYSQL_DLLINIT' environment variable to any value. This
     variable exists only to prevent breakage of existing Windows-only
     applications that do not call *Note `mysql_thread_init()':
     mysql-thread-init. and work okay today. Use of `LIBMYSQL_DLLINIT'
     is discouraged and is removed in MySQL 6.0.  (Bug #37226, Bug
     #33031)

   * *Incompatible Change*: *Note `SHOW STATUS': show-status. took a
     lot of CPU time for calculating the value of the
     `Innodb_buffer_pool_pages_latched' status variable. Now this
     variable is calculated and included in the output of *Note `SHOW
     STATUS': show-status. only if the `UNIV_DEBUG' symbol is defined
     at MySQL build time.  (Bug #36600)

   * *Incompatible Change*: In connection with view creation, the
     server created `arc' directories inside database directories and
     maintained useless copies of `.frm' files there. Creation and
     renaming procedures of those copies as well as creation of `arc'
     directories has been discontinued.

     This change does cause a problem when downgrading to older server
     versions which manifests itself under these circumstances:

       1. Create a view `v_orig' in MySQL 5.0.72 or higher.

       2. Rename the view to `v_new' and then back to `v_orig'.

       3. Downgrade to an older 5.0.x server and run *Note
          `mysql_upgrade': mysql-upgrade.

       4. Try to rename `v_orig' to `v_new' again. This operation fails.

     As a workaround to avoid this problem, use either of these
     approaches:

        * Dump your data using *Note `mysqldump': mysqldump. before
          downgrading and reload the dump file after downgrading.

        * Instead of renaming a view after the downgrade, drop it and
          recreate it.

     The downgrade problem introduced by the fix for this bug has been
     addressed as Bug #40021.  (Bug #17823)

   * *Replication*: When rotating relay log files, the slave deletes
     relay log files and then edits the relay log index file. Formerly,
     if the slave shut down unexpectedly between these two events, the
     relay log index file could then reference relay logs that no longer
     existed. Depending on the circumstances, this could when
     restarting the slave cause either a race condition or the failure
     of replication.  (Bug #38826, Bug #39325)

   * In example option files provided in MySQL distributions, the
     `thread_stack' value was increased from 64K to 128K.  (Bug #41577)

   * *Note `SET PASSWORD': set-password. caused a server crash if the
     account name was given as `CURRENT_USER()'.  (Bug #41456)

   * The *Note `INFORMATION_SCHEMA.SCHEMA_PRIVILEGES':
     schema-privileges-table.  table was limited to 7680 rows.  (Bug
     #41079)

   * In debug builds, obsolete debug code could be used to crash the
     server.  (Bug #41041)

   * *Note `CHECK TABLE ... FOR UPGRADE': check-table. did not check
     for incompatible collation changes made in MySQL 5.0.48 (Bug
     #27562, Bug #29461, Bug #29499). This also affects *Note
     `mysqlcheck': mysqlcheck. and *Note `mysql_upgrade':
     mysql-upgrade, which cause that statement to be executed. See
     *Note checking-table-incompatibilities::.  (Bug #40984) See also
     Bug #39585.

   * Some queries that used a `range checked for each record' scan
     could return incorrect results.  (Bug #40974) See also Bug #44810.

   * Certain *Note `SELECT': select. queries could fail with a
     `Duplicate entry' error.  (Bug #40953)

   * The *Note `FEDERATED': federated-storage-engine. handler had a
     memory leak.  (Bug #40875)

   * `IF(..., CAST(LONGTEXT_VAL AS UNSIGNED), SIGNED_VAL)' as an
     argument to an aggregate function could cause an assertion failure.
     (Bug #40761)

   * Prepared statements permitted invalid dates to be inserted when
     the `ALLOW_INVALID_DATES' SQL mode was not enabled.  (Bug #40365)

   * `mc.exe' is no longer needed to compile MySQL on Windows. This
     makes it possible to build MySQL from source using Visual Studio
     Express 2008.  (Bug #40280)

   * Support for the `revision' field in `.frm' files has been removed.
     This addresses the downgrading problem introduced by the fix for
     Bug #17823.  (Bug #40021)

   * If the operating system is configured to return leap seconds from
     OS time calls or if the MySQL server uses a time zone definition
     that has leap seconds, functions such as `NOW()' could return a
     value having a time part that ends with `:59:60' or `:59:61'. If
     such values are inserted into a table, they would be dumped as is
     by *Note `mysqldump': mysqldump. but considered invalid when
     reloaded, leading to backup/restore problems.

     Now leap second values are returned with a time part that ends
     with `:59:59'. This means that a function such as `NOW()' can
     return the same value for two or three consecutive seconds during
     the leap second. It remains true that literal temporal values
     having a time part that ends with `:59:60' or `:59:61' are
     considered invalid.

     For additional details about leap-second handling, see *Note
     time-zone-leap-seconds::.  (Bug #39920)

   * The server could crash during a sort-order optimization of a
     dependent subquery.  (Bug #39844)

   * With the `ONLY_FULL_GROUP_BY' SQL mode enabled, the check for
     nonaggregated columns in queries with aggregate functions, but
     without a `GROUP BY' clause was treating all the parts of the
     query as if they were in the select list. This is fixed by
     ignoring the nonaggregated columns in the `WHERE' clause.  (Bug
     #39656)

   * The server crashed if an integer field in a CSV file did not have
     delimiting quotation marks.  (Bug #39616)

   * Creating a table with a comment of 62 characters or longer caused
     a server crash.  (Bug #39591)

   * *Note `CHECK TABLE': check-table. failed for *Note `MyISAM':
     myisam-storage-engine.  `INFORMATION_SCHEMA' tables.  (Bug #39541)

   * `InnoDB' could hang trying to open an adaptive hash index.  (Bug
     #39483)

   * For a *Note `TIMESTAMP': datetime. column in an `InnoDB' table,
     testing the column with multiple conditions in the `WHERE' clause
     caused a server crash.  (Bug #39353)

   * The server returned a column type of *Note `VARBINARY':
     binary-varbinary. rather than *Note `DATE': datetime. as the
     result from the `COALESCE()', `IFNULL()', `IF()', `GREATEST()', or
     `LEAST()' functions or `CASE' expression if the result was
     obtained using `filesort' in an anonymous temporary table during
     the query execution.  (Bug #39283)

   * References to local variables in stored procedures are replaced
     with `NAME_CONST(NAME, VALUE)' when written to the binary log.
     However, an `illegal mix of collation' error might occur when
     executing the log contents if the value's collation differed from
     that of the variable. Now information about the variable collation
     is written as well.  (Bug #39182)

   * Some recent releases for Solaris 10 were built on Solaris 10 U5,
     which included a new version of `libnsl.so' that does not work on
     U4 or earlier. To correct this, Solaris 10 builds now are created
     on machines that do not have that upgraded `libnsl.so', so that
     they will work on Solaris 10 installations both with and without
     the upgraded `libnsl.so'.  (Bug #39074)

   * With binary logging enabled *Note `CREATE VIEW': create-view. was
     subject to possible buffer overwrite and a server crash.  (Bug
     #39040)

   * Queries of the form `SELECT ... REGEXP BINARY NULL' could lead to
     a hung or crashed server.  (Bug #39021)

   * Statements of the form `INSERT ... SELECT .. ON DUPLICATE KEY
     UPDATE COL_NAME = DEFAULT' could result in a server crash.  (Bug
     #39002)

   * Column names constructed due to wild-card expansion done inside a
     stored procedure could point to freed memory if the expansion was
     performed after the first call to the stored procedure.  (Bug
     #38823)

   * Repeated *Note `CREATE TABLE ... SELECT': create-table.
     statements, where the created table contained an `AUTO_INCREMENT'
     column, could lead to an assertion failure.  (Bug #38821)

   * If delayed insert failed to upgrade the lock, it did not free the
     temporary memory storage used to keep newly constructed *Note
     `BLOB': blob. values in memory, resulting in a memory leak.  (Bug
     #38693)

   * A server crash resulted from concurrent execution of a
     multiple-table *Note `UPDATE': update. that used a `NATURAL' or
     `USING' join together with *Note `FLUSH TABLES WITH READ LOCK':
     flush. or *Note `ALTER TABLE': alter-table. for the table being
     updated.  (Bug #38691)

   * On ActiveState Perl, `mysql-test-run.pl --start-and-exit' started
     but did not exit.  (Bug #38629)

   * Server-side cursors were not initialized properly, which could
     cause a server crash.  (Bug #38486)

   * Stored procedures involving substrings could crash the server on
     certain platforms due to invalid memory reads.  (Bug #38469)

   * A server crash or Valgrind warnings could result when a stored
     procedure selected from a view that referenced a function.  (Bug
     #38291)

   * Incorrect handling of aggregate functions when loose index scan
     was used caused a server crash.  (Bug #38195)

   * Queries containing a subquery with `DISTINCT' and `ORDER BY' could
     cause a server crash.  (Bug #38191)

   * Queries with a `HAVING' clause could return a spurious row.  (Bug
     #38072)

   * Use of spatial data types in prepared statements could cause
     memory leaks or server crashes.  (Bug #37956, Bug #37671)

   * The server crashed if an argument to a stored procedure was a
     subquery that returned more than one row.  (Bug #37949)

   * When analyzing the possible index use cases, the server was
     incorrectly reusing an internal structure, leading to a server
     crash.  (Bug #37943)

   * A *Note `SELECT': select. with a `NULL NOT IN' condition
     containing a complex subquery from the same table as in the outer
     select caused an assertion failure.  (Bug #37894)

   * For `InnoDB' tables, `ORDER BY ...  DESC' sometimes returned
     results in ascending order.  (Bug #37830)

   * If a table has a `BIT NOT NULL' column `c1' with a length shorter
     than 8 bits and some additional `NOT NULL' columns `c2', ..., and a
     *Note `SELECT': select. query has a `WHERE' clause of the form
     `(c1 = CONSTANT) AND c2 ...', the query could return an unexpected
     result set.  (Bug #37799)

   * Nesting of `IF()' inside of `SUM()' could cause an extreme server
     slowdown.  (Bug #37662)

   * The `MONTHNAME()' and `DAYNAME()' functions returned a binary
     string, so that using `LOWER()' or `UPPER()' had no effect. Now
     `MONTHNAME()' and `DAYNAME()' return a value in
     `character_set_connection' character set.  (Bug #37575)

   * `TIMEDIFF()' was erroneously treated as always returning a
     positive result. Also, `CAST()' of *Note `TIME': time. values to
     *Note `DECIMAL': numeric-types. dropped the sign of negative
     values.  (Bug #37553) See also Bug #42525.

   * *Note `mysqlcheck': mysqlcheck. used *Note `SHOW FULL TABLES':
     show-tables. to get the list of tables in a database. For some
     problems, such as an empty `.frm' file for a table, this would
     fail and *Note `mysqlcheck': mysqlcheck.  then would neglect to
     check other tables in the database.  (Bug #37527)

   * The `<=>' operator could return incorrect results when comparing
     `NULL' to *Note `DATE': datetime, *Note `TIME': time, or *Note
     `DATETIME': datetime. values.  (Bug #37526)

   * Updating a view with a subquery in the `CHECK' option could cause
     an assertion failure.  (Bug #37460)

   * Statements that displayed the value of system variables (for
     example, *Note `SHOW VARIABLES': show-variables.) expect variable
     values to be encoded in `character_set_system'. However, variables
     set from the command line such as `basedir' or `datadir' were
     encoded using `character_set_filesystem' and not converted
     correctly.  (Bug #37339)

   * For a `MyISAM' table with `CHECKSUM = 1' and `ROW_FORMAT =
     DYNAMIC' table options, a data consistency check (maximum record
     length) could fail and cause the table to be marked as corrupted.
     (Bug #37310)

   * The `max_length' result set metadata value was calculated
     incorrectly under some circumstances.  (Bug #37301)

   * *Note `CREATE INDEX': create-index. could crash with `InnoDB'
     plugin 1.0.1.  (Bug #37284)

   * Certain boolean-mode `FULLTEXT' searches that used the truncation
     operator did not return matching records and calculated relevance
     incorrectly.  (Bug #37245)

   * The `NO_BACKSLASH_ESCAPES' SQL mode was ignored for *Note `LOAD
     DATA INFILE': load-data. and `SELECT INTO ... OUTFILE'.  The
     setting is taken into account now.  (Bug #37114)

   * On a 32-bit server built without big tables support, the offset
     argument in a `LIMIT' clause might be truncated due to a 64-bit to
     32-bit cast.  (Bug #37075)

   * If the server failed to expire binary log files at startup, it
     could crash.  (Bug #37027)

   * The code for the `ut_usectime()' function in `InnoDB' did not
     handle errors from the `gettimeofday()' system call. Now it retries
     `gettimeofday()' several times and updates the value of the
     `Innodb_row_lock_time_max' status variable only if `ut_usectime()'
     was successful.  (Bug #36819)

   * Use of `CONVERT()' with `GROUP BY' to convert numeric values to
     *Note `CHAR': char. could return truncated results.  (Bug #36772)

   * A query which had an `ORDER BY DESC' clause that is satisfied with
     a reverse range scan could cause a server crash for some specific
     CPU/compiler combinations.  (Bug #36639)

   * Dumping information about locks in use by sending a `SIGHUP'
     signal to the server or by invoking the *Note `mysqladmin debug':
     mysqladmin. command could lead to a server crash in debug builds
     or to undefined behavior in production builds.  (Bug #36579)

   * The *Note `mysql': mysql. client, when built with Visual Studio
     2005, did not display Japanese characters.  (Bug #36279)

   * When the fractional part in a multiplication of *Note `DECIMAL':
     numeric-types. values overflowed, the server truncated the first
     operand rather than the longest. Now the server truncates so as to
     produce more precise multiplications.  (Bug #36270)

   * A read past the end of the string could occur while parsing the
     value of the `--innodb-data-file-path' option.  (Bug #36149)

   * Host name values in SQL statements were not being checked for
     `'@'', which is illegal according to RFC952.  (Bug #35924)

   * The `UUID()' function returned UUIDs with the wrong time; this was
     because the offset for the time part in UUIDs was miscalculated.
     (Bug #35848)

   * *Note `SHOW CREATE TABLE': show-create-table. did not display a
     printable value for the default value of *Note `BIT':
     numeric-types. columns.  (Bug #35796)

   * *Note `mysql_install_db': mysql-install-db. failed on machines
     that had the host name set to `localhost'.  (Bug #35754)

   * Dynamic plugins failed to load on i5/OS.  (Bug #35743)

   * Freeing of an internal parser stack during parsing of complex
     stored programs caused a server crash.  (Bug #35577, Bug #37269,
     Bug #37228)

   * The `max_length' metadata value was calculated incorrectly for the
     `FORMAT()' function, which could cause incorrect result set
     metadata to be sent to clients.  (Bug #35558)

   * Index scans performed with the `sort_union()' access method
     returned wrong results, caused memory to be leaked, and caused
     temporary files to be deleted when the limit set by
     `sort_buffer_size' was reached.  (Bug #35477, Bug #35478)

   * If the server crashed with an `InnoDB' error due to unavailability
     of undo slots, errors could persist during rollback when the
     server was restarted: There are two `UNDO' slot caches (for *Note
     `INSERT': insert. and *Note `UPDATE': update.). If all slots end
     up in one of the slot caches, a request for a slot from the other
     slot cache would fail. This can happen if the request is for an
     *Note `UPDATE': update. slot and all slots are in the *Note
     `INSERT': insert. slot cache, or vice versa.  (Bug #35352)

   * For `InnoDB' tables, `ALTER TABLE DROP' failed if the name of the
     column to be dropped began with `foreign'.  (Bug #35220)

   * *Note `perror': perror. on Windows did not know about Win32 system
     error codes.  (Bug #34825)

   * *Note `EXPLAIN EXTENDED': explain. evaluation of aggregate
     functions that required a temporary table caused a server crash.
     (Bug #34773)

   * Queries of the form `SELECT ... WHERE STRING = ANY(...)' failed
     when the server used a single-byte character set and the client
     used a multi-byte character set.  (Bug #34760) See also Bug #20835.

   * Using *Note `OPTIMIZE TABLE': optimize-table. as the first
     statement on an `InnoDB' table with an `AUTO_INCREMENT' column
     could cause a server crash.  (Bug #34286)

   * *Note `mysql_install_db': mysql-install-db. failed if the server
     was running with an SQL mode of `TRADITIONAL'. This program now
     resets the SQL mode internally to avoid this problem.  (Bug #34159)

   * Changes to build files were made to enable the MySQL distribution
     to compile on Microsoft Visual C++ Express 2008.  (Bug #33907)

   * The *Note `mysql': mysql. client incorrectly parsed statements
     containing the word `delimiter' in mid-statement.

     This fix is different from the one applied for this bug in MySQL
     5.0.66.  (Bug #33812) See also Bug #38158.

   * For a stored procedure containing a `SELECT * ... RIGHT JOIN'
     query, execution failed for the second call.  (Bug #33811)

   * Previously, use of index hints with views (which do not have
     indexes) produced the error `ERROR 1221 (HY000): Incorrect usage
     of USE/IGNORE INDEX and VIEW'. Now this produces `ERROR 1176
     (HY000): Key '...' doesn't exist in table '...'', the same error
     as for base tables without an appropriate index.  (Bug #33461)

   * Cached queries that used 256 or more tables were not properly
     cached, so that later query invalidation due to a *Note `TRUNCATE
     TABLE': truncate-table. for one of the tables caused the server to
     hang.  (Bug #33362)

   * Some division operations produced a result with incorrect
     precision.  (Bug #31616)

   * *Note `mysql_upgrade': mysql-upgrade. attempted to use the `/proc'
     file system even on systems that do not have it.  (Bug #31605)

   * *Note `mysqldump': mysqldump. could fail to dump views containing
     a large number of columns.  (Bug #31434)

   * Queries executed using join buffering of *Note `BIT':
     numeric-types. columns could produce incorrect results.  (Bug
     #31399)

   * `ALTER TABLE CONVERT TO CHARACTER SET' did not convert *Note
     `TINYTEXT': blob. or *Note `MEDIUMTEXT': blob. columns to a longer
     text type if necessary when converting the column to a different
     character set.  (Bug #31291)

   * For installation on Solaris using `pkgadd' packages, the *Note
     `mysql_install_db': mysql-install-db. script was generated in the
     `scripts' directory, but the temporary files used during the
     process were left there and not deleted.  (Bug #31052)

   * Several MySQL programs could fail if the `HOME' environment
     variable had an empty value.  (Bug #30394)

   * On NetWare, *Note `mysql_install_db': mysql-install-db. could
     appear to execute normally even if it failed to create the initial
     databases.  (Bug #30129)

   * The Serbian translation for the `ER_INCORRECT_GLOBAL_LOCAL_VAR'
     error was corrected.  (Bug #29738)

   * XA transaction rollbacks could result in corrupted transaction
     states and a server crash.  (Bug #28323)

   * The `BUILD/check-cpu' build script failed if `gcc' had a different
     name (such as `gcc.real' on Debian).  (Bug #27526)

   * On Windows, Visual Studio does not take into account some x86
     hardware limitations, which led to incorrect results converting
     large *Note `DOUBLE': numeric-types. values to unsigned *Note
     `BIGINT': numeric-types. values.  (Bug #27483)

   * SSL support was not included in some `generic' RPM packages.  (Bug
     #26760)

   * In some cases, the parser interpreted the `;' character as the end
     of input and misinterpreted stored program definitions.  (Bug
     #26030)

   * The `Questions' status variable is intended as a count of
     statements sent by clients to the server, but was also counting
     statements executed within stored routines.  (Bug #24289)

   * For access to the *Note `INFORMATION_SCHEMA.VIEWS': views-table.
     table, the server did not check the `SHOW VIEW' and *Note
     `SELECT': select.  privileges, leading to inconsistency between
     output from that table and the *Note `SHOW CREATE VIEW':
     show-create-view.  statement.  (Bug #22763)

   * The *Note `FLUSH PRIVILEGES': flush. statement did not produce an
     error when it failed.  (Bug #21226)

   * A race condition between the *Note `mysqld.exe': mysqld.  server
     and the Windows service manager could lead to inability to stop
     the server from the service manager.  (Bug #20430)

   * `mysqld_safe' would sometimes fail to remove the pid file for the
     old `mysql' process after a crash. As a result, the server would
     fail to start due to a false `A mysqld process already exists...'
     error.  (Bug #11122)


File: manual.info,  Node: news-5-0-76,  Next: news-5-0-75,  Prev: news-5-0-77,  Up: news-5-0-x

D.1.22 Changes in MySQL Enterprise 5.0.76 [MRU] (05 January 2009)
-----------------------------------------------------------------

This is a _Monthly Rapid Update_ release of the MySQL Enterprise Server
5.0.

This section documents all changes and bugfixes that have been applied
since the last MySQL Enterprise Server release (5.0.74).  If you would
like to receive more fine-grained and personalized _update alerts_
about fixes that are relevant to the version and features you use,
please consider subscribing to _MySQL Enterprise_ (a commercial MySQL
offering). For more details please see
http://www.mysql.com/products/enterprise/advisors.html.

*Functionality Added or Changed*

   * A new status variable, `Queries', indicates the number of
     statements executed by the server. This includes statements
     executed within stored programs, unlike the `Questions' variable
     which includes only statements sent to the server by clients.
     (Bug #41131)

*Bugs Fixed*

   * *Replication*: When rotating relay log files, the slave deletes
     relay log files and then edits the relay log index file. Formerly,
     if the slave shut down unexpectedly between these two events, the
     relay log index file could then reference relay logs that no longer
     existed. Depending on the circumstances, this could when
     restarting the slave cause either a race condition or the failure
     of replication.  (Bug #38826, Bug #39325)

   * In example option files provided in MySQL distributions, the
     `thread_stack' value was increased from 64K to 128K.  (Bug #41577)

   * *Note `SET PASSWORD': set-password. caused a server crash if the
     account name was given as `CURRENT_USER()'.  (Bug #41456)

   * The *Note `INFORMATION_SCHEMA.SCHEMA_PRIVILEGES':
     schema-privileges-table.  table was limited to 7680 rows.  (Bug
     #41079)

   * In debug builds, obsolete debug code could be used to crash the
     server.  (Bug #41041)

   * Some queries that used a `range checked for each record' scan
     could return incorrect results.  (Bug #40974) See also Bug #44810.

   * Certain *Note `SELECT': select. queries could fail with a
     `Duplicate entry' error.  (Bug #40953)

   * `IF(..., CAST(LONGTEXT_VAL AS UNSIGNED), SIGNED_VAL)' as an
     argument to an aggregate function could cause an assertion failure.
     (Bug #40761)

   * The server crashed if an integer field in a CSV file did not have
     delimiting quotation marks.  (Bug #39616)

   * Creating a table with a comment of 62 characters or longer caused
     a server crash.  (Bug #39591)

   * `InnoDB' could hang trying to open an adaptive hash index.  (Bug
     #39483)

   * Use of spatial data types in prepared statements could cause
     memory leaks or server crashes.  (Bug #37956, Bug #37671)

   * The `MONTHNAME()' and `DAYNAME()' functions returned a binary
     string, so that using `LOWER()' or `UPPER()' had no effect. Now
     `MONTHNAME()' and `DAYNAME()' return a value in
     `character_set_connection' character set.  (Bug #37575)

   * Certain boolean-mode `FULLTEXT' searches that used the truncation
     operator did not return matching records and calculated relevance
     incorrectly.  (Bug #37245)

   * The code for the `ut_usectime()' function in `InnoDB' did not
     handle errors from the `gettimeofday()' system call. Now it retries
     `gettimeofday()' several times and updates the value of the
     `Innodb_row_lock_time_max' status variable only if `ut_usectime()'
     was successful.  (Bug #36819)

   * A read past the end of the string could occur while parsing the
     value of the `--innodb-data-file-path' option.  (Bug #36149)

   * *Note `SHOW CREATE TABLE': show-create-table. did not display a
     printable value for the default value of *Note `BIT':
     numeric-types. columns.  (Bug #35796)

   * The `max_length' metadata value was calculated incorrectly for the
     `FORMAT()' function, which could cause incorrect result set
     metadata to be sent to clients.  (Bug #35558)

   * *Note `EXPLAIN EXTENDED': explain. evaluation of aggregate
     functions that required a temporary table caused a server crash.
     (Bug #34773)

   * The *Note `mysql': mysql. client incorrectly parsed statements
     containing the word `delimiter' in mid-statement.

     This fix is different from the one applied for this bug in MySQL
     5.0.66.  (Bug #33812) See also Bug #38158.

   * Queries executed using join buffering of *Note `BIT':
     numeric-types. columns could produce incorrect results.  (Bug
     #31399)

   * `ALTER TABLE CONVERT TO CHARACTER SET' did not convert *Note
     `TINYTEXT': blob. or *Note `MEDIUMTEXT': blob. columns to a longer
     text type if necessary when converting the column to a different
     character set.  (Bug #31291)

   * On Windows, Visual Studio does not take into account some x86
     hardware limitations, which led to incorrect results converting
     large *Note `DOUBLE': numeric-types. values to unsigned *Note
     `BIGINT': numeric-types. values.  (Bug #27483)

   * SSL support was not included in some `generic' RPM packages.  (Bug
     #26760)


File: manual.info,  Node: news-5-0-75,  Next: news-5-0-74sp1,  Prev: news-5-0-76,  Up: news-5-0-x

D.1.23 Changes in MySQL Community Server 5.0.75 (17 December 2008)
------------------------------------------------------------------

This is a bugfix release for the current MySQL Community Server
production release family. It replaces MySQL 5.0.67.

*Functionality Added or Changed*

   * *Security Enhancement*: To enable stricter control over the
     location from which user-defined functions can be loaded, the
     `plugin_dir' system variable has been backported from MySQL 5.1.
     If the value is nonempty, user-defined function object files can
     be loaded only from the directory named by this variable. If the
     value is empty, the behavior that is used prior to the inclusion of
     `plugin_dir' applies: The UDF object files must be located in a
     directory that is searched by your system's dynamic linker.

     If the plugin directory is writable by the server, it may be
     possible for a user to write executable code to a file in the
     directory using *Note `SELECT ... INTO DUMPFILE': select. This can
     be prevented by making `plugin_dir' read only to the server or by
     setting `--secure-file-priv' to a directory where *Note `SELECT':
     select. writes can be made safely.  (Bug #37428)

   * Previously, index hints did not work for `FULLTEXT' searches. Now
     they work as follows:

     For natural language mode searches, index hints are silently
     ignored. For example, `IGNORE INDEX(i)' is ignored with no warning
     and the index is still used.

     For boolean mode searches, index hints are honored.  (Bug #38842)

*Bugs Fixed*

   * *Important Change*: *Security Fix*: Additional corrections were
     made for the symlink-related privilege problem originally
     addressed in MySQL 5.0.60. The original fix did not correctly
     handle the data directory path name if it contained symlinked
     directories in its path, and the check was made only at
     table-creation time, not at table-opening time later.  (Bug
     #32167, CVE-2008-2079) See also Bug #39277.

   * *Security Enhancement*: The server consumed excess memory while
     parsing statements with hundreds or thousands of nested boolean
     conditions (such as `OR (OR ... (OR ... ))'). This could lead to a
     server crash or incorrect statement execution, or cause other
     client statements to fail due to lack of memory. The latter result
     constitutes a denial of service.  (Bug #38296)

   * *Incompatible Change*: There were some problems using `DllMain()'
     hook functions on Windows that automatically do global and
     per-thread initialization for `libmysqld.dll':

        * Per-thread initialization: MySQL internally counts the number
          of active threads, which causes a delay in `my_end()' if not
          all threads have exited. But there are threads that can be
          started either by Windows internally (often in TCP/IP
          scenarios) or by users.  Those threads do not necessarily use
          `libmysql.dll' functionality but still contribute to the
          open-thread count. (One symptom is a five-second delay in
          times for PHP scripts to finish.)

        * Process-initialization: *Note `my_init()': my-init. calls
          `WSAStartup' that itself loads DLLs and can lead to a
          deadlock in the Windows loader.

     To correct these problems, DLL initialization code now is not
     invoked from `libmysql.dll' by default. To obtain the previous
     behavior (DLL initialization code will be called), set the
     `LIBMYSQL_DLLINIT' environment variable to any value. This
     variable exists only to prevent breakage of existing Windows-only
     applications that do not call *Note `mysql_thread_init()':
     mysql-thread-init. and work okay today. Use of `LIBMYSQL_DLLINIT'
     is discouraged and is removed in MySQL 6.0.  (Bug #37226, Bug
     #33031)

   * *Incompatible Change*: *Note `SHOW STATUS': show-status. took a
     lot of CPU time for calculating the value of the
     `Innodb_buffer_pool_pages_latched' status variable. Now this
     variable is calculated and included in the output of *Note `SHOW
     STATUS': show-status. only if the `UNIV_DEBUG' symbol is defined
     at MySQL build time.  (Bug #36600)

   * *Incompatible Change*: In connection with view creation, the
     server created `arc' directories inside database directories and
     maintained useless copies of `.frm' files there. Creation and
     renaming procedures of those copies as well as creation of `arc'
     directories has been discontinued.

     This change does cause a problem when downgrading to older server
     versions which manifests itself under these circumstances:

       1. Create a view `v_orig' in MySQL 5.0.72 or higher.

       2. Rename the view to `v_new' and then back to `v_orig'.

       3. Downgrade to an older 5.0.x server and run *Note
          `mysql_upgrade': mysql-upgrade.

       4. Try to rename `v_orig' to `v_new' again. This operation fails.

     As a workaround to avoid this problem, use either of these
     approaches:

        * Dump your data using *Note `mysqldump': mysqldump. before
          downgrading and reload the dump file after downgrading.

        * Instead of renaming a view after the downgrade, drop it and
          recreate it.

     The downgrade problem introduced by the fix for this bug has been
     addressed as Bug #40021.  (Bug #17823)

   * *Note `CHECK TABLE ... FOR UPGRADE': check-table. did not check
     for incompatible collation changes made in MySQL 5.0.48 (Bug
     #27562, Bug #29461, Bug #29499). This also affects *Note
     `mysqlcheck': mysqlcheck. and *Note `mysql_upgrade':
     mysql-upgrade, which cause that statement to be executed. See
     *Note checking-table-incompatibilities::.  (Bug #40984) See also
     Bug #39585.

   * The *Note `FEDERATED': federated-storage-engine. handler had a
     memory leak.  (Bug #40875)

   * Prepared statements permitted invalid dates to be inserted when
     the `ALLOW_INVALID_DATES' SQL mode was not enabled.  (Bug #40365)

   * `mc.exe' is no longer needed to compile MySQL on Windows. This
     makes it possible to build MySQL from source using Visual Studio
     Express 2008.  (Bug #40280)

   * Support for the `revision' field in `.frm' files has been removed.
     This addresses the downgrading problem introduced by the fix for
     Bug #17823.  (Bug #40021)

   * If the operating system is configured to return leap seconds from
     OS time calls or if the MySQL server uses a time zone definition
     that has leap seconds, functions such as `NOW()' could return a
     value having a time part that ends with `:59:60' or `:59:61'. If
     such values are inserted into a table, they would be dumped as is
     by *Note `mysqldump': mysqldump. but considered invalid when
     reloaded, leading to backup/restore problems.

     Now leap second values are returned with a time part that ends
     with `:59:59'. This means that a function such as `NOW()' can
     return the same value for two or three consecutive seconds during
     the leap second. It remains true that literal temporal values
     having a time part that ends with `:59:60' or `:59:61' are
     considered invalid.

     For additional details about leap-second handling, see *Note
     time-zone-leap-seconds::.  (Bug #39920)

   * The server could crash during a sort-order optimization of a
     dependent subquery.  (Bug #39844)

   * With the `ONLY_FULL_GROUP_BY' SQL mode enabled, the check for
     nonaggregated columns in queries with aggregate functions, but
     without a `GROUP BY' clause was treating all the parts of the
     query as if they were in the select list. This is fixed by
     ignoring the nonaggregated columns in the `WHERE' clause.  (Bug
     #39656)

   * *Note `CHECK TABLE': check-table. failed for *Note `MyISAM':
     myisam-storage-engine.  `INFORMATION_SCHEMA' tables.  (Bug #39541)

   * For a *Note `TIMESTAMP': datetime. column in an `InnoDB' table,
     testing the column with multiple conditions in the `WHERE' clause
     caused a server crash.  (Bug #39353)

   * The server returned a column type of *Note `VARBINARY':
     binary-varbinary. rather than *Note `DATE': datetime. as the
     result from the `COALESCE()', `IFNULL()', `IF()', `GREATEST()', or
     `LEAST()' functions or `CASE' expression if the result was
     obtained using `filesort' in an anonymous temporary table during
     the query execution.  (Bug #39283)

   * References to local variables in stored procedures are replaced
     with `NAME_CONST(NAME, VALUE)' when written to the binary log.
     However, an `illegal mix of collation' error might occur when
     executing the log contents if the value's collation differed from
     that of the variable. Now information about the variable collation
     is written as well.  (Bug #39182)

   * Some recent releases for Solaris 10 were built on Solaris 10 U5,
     which included a new version of `libnsl.so' that does not work on
     U4 or earlier. To correct this, Solaris 10 builds now are created
     on machines that do not have that upgraded `libnsl.so', so that
     they will work on Solaris 10 installations both with and without
     the upgraded `libnsl.so'.  (Bug #39074)

   * With binary logging enabled *Note `CREATE VIEW': create-view. was
     subject to possible buffer overwrite and a server crash.  (Bug
     #39040)

   * Queries of the form `SELECT ... REGEXP BINARY NULL' could lead to
     a hung or crashed server.  (Bug #39021)

   * Statements of the form `INSERT ... SELECT .. ON DUPLICATE KEY
     UPDATE COL_NAME = DEFAULT' could result in a server crash.  (Bug
     #39002)

   * Column names constructed due to wild-card expansion done inside a
     stored procedure could point to freed memory if the expansion was
     performed after the first call to the stored procedure.  (Bug
     #38823)

   * Repeated *Note `CREATE TABLE ... SELECT': create-table.
     statements, where the created table contained an `AUTO_INCREMENT'
     column, could lead to an assertion failure.  (Bug #38821)

   * If delayed insert failed to upgrade the lock, it did not free the
     temporary memory storage used to keep newly constructed *Note
     `BLOB': blob. values in memory, resulting in a memory leak.  (Bug
     #38693)

   * A server crash resulted from concurrent execution of a
     multiple-table *Note `UPDATE': update. that used a `NATURAL' or
     `USING' join together with *Note `FLUSH TABLES WITH READ LOCK':
     flush. or *Note `ALTER TABLE': alter-table. for the table being
     updated.  (Bug #38691)

   * On ActiveState Perl, `mysql-test-run.pl --start-and-exit' started
     but did not exit.  (Bug #38629)

   * Server-side cursors were not initialized properly, which could
     cause a server crash.  (Bug #38486)

   * Stored procedures involving substrings could crash the server on
     certain platforms due to invalid memory reads.  (Bug #38469)

   * A server crash or Valgrind warnings could result when a stored
     procedure selected from a view that referenced a function.  (Bug
     #38291)

   * Incorrect handling of aggregate functions when loose index scan
     was used caused a server crash.  (Bug #38195)

   * Queries containing a subquery with `DISTINCT' and `ORDER BY' could
     cause a server crash.  (Bug #38191)

   * Queries with a `HAVING' clause could return a spurious row.  (Bug
     #38072)

   * The server crashed if an argument to a stored procedure was a
     subquery that returned more than one row.  (Bug #37949)

   * When analyzing the possible index use cases, the server was
     incorrectly reusing an internal structure, leading to a server
     crash.  (Bug #37943)

   * A *Note `SELECT': select. with a `NULL NOT IN' condition
     containing a complex subquery from the same table as in the outer
     select caused an assertion failure.  (Bug #37894)

   * For `InnoDB' tables, `ORDER BY ...  DESC' sometimes returned
     results in ascending order.  (Bug #37830)

   * If a table has a `BIT NOT NULL' column `c1' with a length shorter
     than 8 bits and some additional `NOT NULL' columns `c2', ..., and a
     *Note `SELECT': select. query has a `WHERE' clause of the form
     `(c1 = CONSTANT) AND c2 ...', the query could return an unexpected
     result set.  (Bug #37799)

   * Nesting of `IF()' inside of `SUM()' could cause an extreme server
     slowdown.  (Bug #37662)

   * `TIMEDIFF()' was erroneously treated as always returning a
     positive result. Also, `CAST()' of *Note `TIME': time. values to
     *Note `DECIMAL': numeric-types. dropped the sign of negative
     values.  (Bug #37553) See also Bug #42525.

   * *Note `mysqlcheck': mysqlcheck. used *Note `SHOW FULL TABLES':
     show-tables. to get the list of tables in a database. For some
     problems, such as an empty `.frm' file for a table, this would
     fail and *Note `mysqlcheck': mysqlcheck.  then would neglect to
     check other tables in the database.  (Bug #37527)

   * The `<=>' operator could return incorrect results when comparing
     `NULL' to *Note `DATE': datetime, *Note `TIME': time, or *Note
     `DATETIME': datetime. values.  (Bug #37526)

   * Updating a view with a subquery in the `CHECK' option could cause
     an assertion failure.  (Bug #37460)

   * Statements that displayed the value of system variables (for
     example, *Note `SHOW VARIABLES': show-variables.) expect variable
     values to be encoded in `character_set_system'. However, variables
     set from the command line such as `basedir' or `datadir' were
     encoded using `character_set_filesystem' and not converted
     correctly.  (Bug #37339)

   * For a `MyISAM' table with `CHECKSUM = 1' and `ROW_FORMAT =
     DYNAMIC' table options, a data consistency check (maximum record
     length) could fail and cause the table to be marked as corrupted.
     (Bug #37310)

   * The `max_length' result set metadata value was calculated
     incorrectly under some circumstances.  (Bug #37301)

   * *Note `CREATE INDEX': create-index. could crash with `InnoDB'
     plugin 1.0.1.  (Bug #37284)

   * The `NO_BACKSLASH_ESCAPES' SQL mode was ignored for *Note `LOAD
     DATA INFILE': load-data. and `SELECT INTO ... OUTFILE'.  The
     setting is taken into account now.  (Bug #37114)

   * On a 32-bit server built without big tables support, the offset
     argument in a `LIMIT' clause might be truncated due to a 64-bit to
     32-bit cast.  (Bug #37075)

   * If the server failed to expire binary log files at startup, it
     could crash.  (Bug #37027)

   * Use of `CONVERT()' with `GROUP BY' to convert numeric values to
     *Note `CHAR': char. could return truncated results.  (Bug #36772)

   * A query which had an `ORDER BY DESC' clause that is satisfied with
     a reverse range scan could cause a server crash for some specific
     CPU/compiler combinations.  (Bug #36639)

   * Dumping information about locks in use by sending a `SIGHUP'
     signal to the server or by invoking the *Note `mysqladmin debug':
     mysqladmin. command could lead to a server crash in debug builds
     or to undefined behavior in production builds.  (Bug #36579)

   * The *Note `mysql': mysql. client, when built with Visual Studio
     2005, did not display Japanese characters.  (Bug #36279)

   * When the fractional part in a multiplication of *Note `DECIMAL':
     numeric-types. values overflowed, the server truncated the first
     operand rather than the longest. Now the server truncates so as to
     produce more precise multiplications.  (Bug #36270)

   * Host name values in SQL statements were not being checked for
     `'@'', which is illegal according to RFC952.  (Bug #35924)

   * The `UUID()' function returned UUIDs with the wrong time; this was
     because the offset for the time part in UUIDs was miscalculated.
     (Bug #35848)

   * *Note `mysql_install_db': mysql-install-db. failed on machines
     that had the host name set to `localhost'.  (Bug #35754)

   * Dynamic plugins failed to load on i5/OS.  (Bug #35743)

   * Freeing of an internal parser stack during parsing of complex
     stored programs caused a server crash.  (Bug #35577, Bug #37269,
     Bug #37228)

   * Index scans performed with the `sort_union()' access method
     returned wrong results, caused memory to be leaked, and caused
     temporary files to be deleted when the limit set by
     `sort_buffer_size' was reached.  (Bug #35477, Bug #35478)

   * If the server crashed with an `InnoDB' error due to unavailability
     of undo slots, errors could persist during rollback when the
     server was restarted: There are two `UNDO' slot caches (for *Note
     `INSERT': insert. and *Note `UPDATE': update.). If all slots end
     up in one of the slot caches, a request for a slot from the other
     slot cache would fail. This can happen if the request is for an
     *Note `UPDATE': update. slot and all slots are in the *Note
     `INSERT': insert. slot cache, or vice versa.  (Bug #35352)

   * For `InnoDB' tables, `ALTER TABLE DROP' failed if the name of the
     column to be dropped began with `foreign'.  (Bug #35220)

   * *Note `perror': perror. on Windows did not know about Win32 system
     error codes.  (Bug #34825)

   * Queries of the form `SELECT ... WHERE STRING = ANY(...)' failed
     when the server used a single-byte character set and the client
     used a multi-byte character set.  (Bug #34760) See also Bug #20835.

   * Using *Note `OPTIMIZE TABLE': optimize-table. as the first
     statement on an `InnoDB' table with an `AUTO_INCREMENT' column
     could cause a server crash.  (Bug #34286)

   * *Note `mysql_install_db': mysql-install-db. failed if the server
     was running with an SQL mode of `TRADITIONAL'. This program now
     resets the SQL mode internally to avoid this problem.  (Bug #34159)

   * Changes to build files were made to enable the MySQL distribution
     to compile on Microsoft Visual C++ Express 2008.  (Bug #33907)

   * For a stored procedure containing a `SELECT * ... RIGHT JOIN'
     query, execution failed for the second call.  (Bug #33811)

   * Previously, use of index hints with views (which do not have
     indexes) produced the error `ERROR 1221 (HY000): Incorrect usage
     of USE/IGNORE INDEX and VIEW'. Now this produces `ERROR 1176
     (HY000): Key '...' doesn't exist in table '...'', the same error
     as for base tables without an appropriate index.  (Bug #33461)

   * Cached queries that used 256 or more tables were not properly
     cached, so that later query invalidation due to a *Note `TRUNCATE
     TABLE': truncate-table. for one of the tables caused the server to
     hang.  (Bug #33362)

   * Some division operations produced a result with incorrect
     precision.  (Bug #31616)

   * *Note `mysql_upgrade': mysql-upgrade. attempted to use the `/proc'
     file system even on systems that do not have it.  (Bug #31605)

   * *Note `mysqldump': mysqldump. could fail to dump views containing
     a large number of columns.  (Bug #31434)

   * Several MySQL programs could fail if the `HOME' environment
     variable had an empty value.  (Bug #30394)

   * On NetWare, *Note `mysql_install_db': mysql-install-db. could
     appear to execute normally even if it failed to create the initial
     databases.  (Bug #30129)

   * The Serbian translation for the `ER_INCORRECT_GLOBAL_LOCAL_VAR'
     error was corrected.  (Bug #29738)

   * XA transaction rollbacks could result in corrupted transaction
     states and a server crash.  (Bug #28323)

   * The `BUILD/check-cpu' build script failed if `gcc' had a different
     name (such as `gcc.real' on Debian).  (Bug #27526)

   * In some cases, the parser interpreted the `;' character as the end
     of input and misinterpreted stored program definitions.  (Bug
     #26030)

   * The `Questions' status variable is intended as a count of
     statements sent by clients to the server, but was also counting
     statements executed within stored routines.  (Bug #24289)

   * For access to the *Note `INFORMATION_SCHEMA.VIEWS': views-table.
     table, the server did not check the `SHOW VIEW' and *Note
     `SELECT': select.  privileges, leading to inconsistency between
     output from that table and the *Note `SHOW CREATE VIEW':
     show-create-view.  statement.  (Bug #22763)

   * The *Note `FLUSH PRIVILEGES': flush. statement did not produce an
     error when it failed.  (Bug #21226)

   * A race condition between the *Note `mysqld.exe': mysqld.  server
     and the Windows service manager could lead to inability to stop
     the server from the service manager.  (Bug #20430)

   * `mysqld_safe' would sometimes fail to remove the pid file for the
     old `mysql' process after a crash. As a result, the server would
     fail to start due to a false `A mysqld process already exists...'
     error.  (Bug #11122)


File: manual.info,  Node: news-5-0-74sp1,  Next: news-5-0-74,  Prev: news-5-0-75,  Up: news-5-0-x

D.1.24 Changes in MySQL Enterprise 5.0.74sp1 [QSP] (30 April 2009)
------------------------------------------------------------------

This is a _Service Pack_ release of the MySQL Enterprise Server 5.0.

This section documents all changes and bugfixes that have been applied
since the last MySQL Enterprise Server release (5.0.74).

If you would like to receive more fine-grained and personalized _update
alerts_ about fixes that are relevant to the version and features you
use, please consider subscribing to _MySQL Enterprise_ (a commercial
MySQL offering). For more details please see
http://www.mysql.com/products/enterprise/advisors.html.

*Functionality Added or Changed*

   * The `libedit' library was upgraded to version 2.11.  (Bug #42433)

*Bugs Fixed*

   * An attempt by a user who did not have the `SUPER' privilege to
     kill a system thread could cause a server crash.  (Bug #43748)

   * Tables could enter open table cache for a thread without being
     properly cleaned up, leading to a server crash.  (Bug #42419)

   * The SSL certficates included with MySQL distributions were
     regenerated because the previous ones had expired.  (Bug #42366)

   * Some queries using `NAME_CONST(.. COLLATE ...)' led to a server
     crash due to a failed type cast.  (Bug #42014)

   * `DATE_FORMAT()' could cause a server crash for year-zero dates.
     (Bug #41470)

   * *Note `SET PASSWORD': set-password. caused a server crash if the
     account name was given as `CURRENT_USER()'.  (Bug #41456)

   * When substituting system constant functions with a constant
     result, the server was not expecting `NULL' function return values
     and could crash.  (Bug #41437)

   * Creating a table with a comment of 62 characters or longer caused
     a server crash.  (Bug #39591)

   * *Note `EXPLAIN EXTENDED': explain. evaluation of aggregate
     functions that required a temporary table caused a server crash.
     (Bug #34773)


File: manual.info,  Node: news-5-0-74,  Next: news-5-0-72sp1,  Prev: news-5-0-74sp1,  Up: news-5-0-x

D.1.25 Changes in MySQL Enterprise 5.0.74 [MRU] (03 December 2008)
------------------------------------------------------------------

This is a _Monthly Rapid Update_ release of the MySQL Enterprise Server
5.0.

This section documents all changes and bugfixes that have been applied
since the last MySQL Enterprise Server release (5.0.72).  If you would
like to receive more fine-grained and personalized _update alerts_
about fixes that are relevant to the version and features you use,
please consider subscribing to _MySQL Enterprise_ (a commercial MySQL
offering). For more details please see
http://www.mysql.com/products/enterprise/advisors.html.

*Functionality Added or Changed*

   * Previously, index hints did not work for `FULLTEXT' searches. Now
     they work as follows:

     For natural language mode searches, index hints are silently
     ignored. For example, `IGNORE INDEX(i)' is ignored with no warning
     and the index is still used.

     For boolean mode searches, index hints are honored.  (Bug #38842)

*Bugs Fixed*

   * *Note `CHECK TABLE ... FOR UPGRADE': check-table. did not check
     for incompatible collation changes made in MySQL 5.0.48 (Bug
     #27562, Bug #29461, Bug #29499). This also affects *Note
     `mysqlcheck': mysqlcheck. and *Note `mysql_upgrade':
     mysql-upgrade, which cause that statement to be executed. See
     *Note checking-table-incompatibilities::.  (Bug #40984) See also
     Bug #39585.

   * The *Note `FEDERATED': federated-storage-engine. handler had a
     memory leak.  (Bug #40875)

   * Prepared statements permitted invalid dates to be inserted when
     the `ALLOW_INVALID_DATES' SQL mode was not enabled.  (Bug #40365)

   * Support for the `revision' field in `.frm' files has been removed.
     This addresses the downgrading problem introduced by the fix for
     Bug #17823.  (Bug #40021)

   * If the operating system is configured to return leap seconds from
     OS time calls or if the MySQL server uses a time zone definition
     that has leap seconds, functions such as `NOW()' could return a
     value having a time part that ends with `:59:60' or `:59:61'. If
     such values are inserted into a table, they would be dumped as is
     by *Note `mysqldump': mysqldump. but considered invalid when
     reloaded, leading to backup/restore problems.

     Now leap second values are returned with a time part that ends
     with `:59:59'. This means that a function such as `NOW()' can
     return the same value for two or three consecutive seconds during
     the leap second. It remains true that literal temporal values
     having a time part that ends with `:59:60' or `:59:61' are
     considered invalid.

     For additional details about leap-second handling, see *Note
     time-zone-leap-seconds::.  (Bug #39920)

   * With the `ONLY_FULL_GROUP_BY' SQL mode enabled, the check for
     nonaggregated columns in queries with aggregate functions, but
     without a `GROUP BY' clause was treating all the parts of the
     query as if they were in the select list. This is fixed by
     ignoring the nonaggregated columns in the `WHERE' clause.  (Bug
     #39656)

   * *Note `CHECK TABLE': check-table. failed for *Note `MyISAM':
     myisam-storage-engine.  `INFORMATION_SCHEMA' tables.  (Bug #39541)

   * With binary logging enabled *Note `CREATE VIEW': create-view. was
     subject to possible buffer overwrite and a server crash.  (Bug
     #39040)

   * Queries with a `HAVING' clause could return a spurious row.  (Bug
     #38072)

   * `TIMEDIFF()' was erroneously treated as always returning a
     positive result. Also, `CAST()' of *Note `TIME': time. values to
     *Note `DECIMAL': numeric-types. dropped the sign of negative
     values.  (Bug #37553) See also Bug #42525.

   * *Note `mysqlcheck': mysqlcheck. used *Note `SHOW FULL TABLES':
     show-tables. to get the list of tables in a database. For some
     problems, such as an empty `.frm' file for a table, this would
     fail and *Note `mysqlcheck': mysqlcheck.  then would neglect to
     check other tables in the database.  (Bug #37527)

   * Updating a view with a subquery in the `CHECK' option could cause
     an assertion failure.  (Bug #37460)

   * Statements that displayed the value of system variables (for
     example, *Note `SHOW VARIABLES': show-variables.) expect variable
     values to be encoded in `character_set_system'. However, variables
     set from the command line such as `basedir' or `datadir' were
     encoded using `character_set_filesystem' and not converted
     correctly.  (Bug #37339)

   * *Note `CREATE INDEX': create-index. could crash with `InnoDB'
     plugin 1.0.1.  (Bug #37284)

   * Use of `CONVERT()' with `GROUP BY' to convert numeric values to
     *Note `CHAR': char. could return truncated results.  (Bug #36772)

   * The *Note `mysql': mysql. client, when built with Visual Studio
     2005, did not display Japanese characters.  (Bug #36279)

   * *Note `perror': perror. on Windows did not know about Win32 system
     error codes.  (Bug #34825)

   * Queries of the form `SELECT ... WHERE STRING = ANY(...)' failed
     when the server used a single-byte character set and the client
     used a multi-byte character set.  (Bug #34760) See also Bug #20835.

   * For a stored procedure containing a `SELECT * ... RIGHT JOIN'
     query, execution failed for the second call.  (Bug #33811)

   * Previously, use of index hints with views (which do not have
     indexes) produced the error `ERROR 1221 (HY000): Incorrect usage
     of USE/IGNORE INDEX and VIEW'. Now this produces `ERROR 1176
     (HY000): Key '...' doesn't exist in table '...'', the same error
     as for base tables without an appropriate index.  (Bug #33461)

   * Some division operations produced a result with incorrect
     precision.  (Bug #31616)

   * A race condition between the *Note `mysqld.exe': mysqld.  server
     and the Windows service manager could lead to inability to stop
     the server from the service manager.  (Bug #20430)


File: manual.info,  Node: news-5-0-72sp1,  Next: news-5-0-72,  Prev: news-5-0-74,  Up: news-5-0-x

D.1.26 Changes in MySQL Enterprise 5.0.72sp1 [QSP] (13 January 2009)
--------------------------------------------------------------------

This is a _Service Pack_ release of the MySQL Enterprise Server 5.0.

This section documents all changes and bugfixes that have been applied
since the last MySQL Enterprise Server release (5.0.72).

If you would like to receive more fine-grained and personalized _update
alerts_ about fixes that are relevant to the version and features you
use, please consider subscribing to _MySQL Enterprise_ (a commercial
MySQL offering). For more details please see
http://www.mysql.com/products/enterprise/advisors.html.

*Functionality Added or Changed*

   * Previously, index hints did not work for `FULLTEXT' searches. Now
     they work as follows:

     For natural language mode searches, index hints are silently
     ignored. For example, `IGNORE INDEX(i)' is ignored with no warning
     and the index is still used.

     For boolean mode searches, index hints are honored.  (Bug #38842)

*Bugs Fixed*

   * *MySQL Cluster*: *Packaging*: Packages for MySQL Cluster were
     missing the `libndbclient.so' and `libndbclient.a' files.  (Bug
     #42278)

   * Support for the `revision' field in `.frm' files has been removed.
     This addresses the downgrading problem introduced by the fix for
     Bug #17823.  (Bug #40021)

   * If the operating system is configured to return leap seconds from
     OS time calls or if the MySQL server uses a time zone definition
     that has leap seconds, functions such as `NOW()' could return a
     value having a time part that ends with `:59:60' or `:59:61'. If
     such values are inserted into a table, they would be dumped as is
     by *Note `mysqldump': mysqldump. but considered invalid when
     reloaded, leading to backup/restore problems.

     Now leap second values are returned with a time part that ends
     with `:59:59'. This means that a function such as `NOW()' can
     return the same value for two or three consecutive seconds during
     the leap second. It remains true that literal temporal values
     having a time part that ends with `:59:60' or `:59:61' are
     considered invalid.

     For additional details about leap-second handling, see *Note
     time-zone-leap-seconds::.  (Bug #39920)

   * Queries of the form `SELECT ... WHERE STRING = ANY(...)' failed
     when the server used a single-byte character set and the client
     used a multi-byte character set.  (Bug #34760) See also Bug #20835.


File: manual.info,  Node: news-5-0-72,  Next: news-5-0-70,  Prev: news-5-0-72sp1,  Up: news-5-0-x

D.1.27 Changes in MySQL Enterprise 5.0.72 [MRU] (24 October 2008)
-----------------------------------------------------------------

This is a _Monthly Rapid Update_ release of the MySQL Enterprise Server
5.0.

This section documents all changes and bugfixes that have been applied
since the last MySQL Enterprise Server release (5.0.70).  If you would
like to receive more fine-grained and personalized _update alerts_
about fixes that are relevant to the version and features you use,
please consider subscribing to _MySQL Enterprise_ (a commercial MySQL
offering). For more details please see
http://www.mysql.com/products/enterprise/advisors.html.

*Bugs Fixed*

   * *Incompatible Change*: In connection with view creation, the
     server created `arc' directories inside database directories and
     maintained useless copies of `.frm' files there. Creation and
     renaming procedures of those copies as well as creation of `arc'
     directories has been discontinued.

     This change does cause a problem when downgrading to older server
     versions which manifests itself under these circumstances:

       1. Create a view `v_orig' in MySQL 5.0.72 or higher.

       2. Rename the view to `v_new' and then back to `v_orig'.

       3. Downgrade to an older 5.0.x server and run *Note
          `mysql_upgrade': mysql-upgrade.

       4. Try to rename `v_orig' to `v_new' again. This operation fails.

     As a workaround to avoid this problem, use either of these
     approaches:

        * Dump your data using *Note `mysqldump': mysqldump. before
          downgrading and reload the dump file after downgrading.

        * Instead of renaming a view after the downgrade, drop it and
          recreate it.

     The downgrade problem introduced by the fix for this bug has been
     addressed as Bug #40021.  (Bug #17823)

   * `mc.exe' is no longer needed to compile MySQL on Windows. This
     makes it possible to build MySQL from source using Visual Studio
     Express 2008.  (Bug #40280)

   * The server could crash during a sort-order optimization of a
     dependent subquery.  (Bug #39844)

   * The server returned a column type of *Note `VARBINARY':
     binary-varbinary. rather than *Note `DATE': datetime. as the
     result from the `COALESCE()', `IFNULL()', `IF()', `GREATEST()', or
     `LEAST()' functions or `CASE' expression if the result was
     obtained using `filesort' in an anonymous temporary table during
     the query execution.  (Bug #39283)

   * References to local variables in stored procedures are replaced
     with `NAME_CONST(NAME, VALUE)' when written to the binary log.
     However, an `illegal mix of collation' error might occur when
     executing the log contents if the value's collation differed from
     that of the variable. Now information about the variable collation
     is written as well.  (Bug #39182)

   * Some recent releases for Solaris 10 were built on Solaris 10 U5,
     which included a new version of `libnsl.so' that does not work on
     U4 or earlier. To correct this, Solaris 10 builds now are created
     on machines that do not have that upgraded `libnsl.so', so that
     they will work on Solaris 10 installations both with and without
     the upgraded `libnsl.so'.  (Bug #39074)

   * Column names constructed due to wild-card expansion done inside a
     stored procedure could point to freed memory if the expansion was
     performed after the first call to the stored procedure.  (Bug
     #38823)

   * If delayed insert failed to upgrade the lock, it did not free the
     temporary memory storage used to keep newly constructed *Note
     `BLOB': blob. values in memory, resulting in a memory leak.  (Bug
     #38693)

   * A server crash resulted from concurrent execution of a
     multiple-table *Note `UPDATE': update. that used a `NATURAL' or
     `USING' join together with *Note `FLUSH TABLES WITH READ LOCK':
     flush. or *Note `ALTER TABLE': alter-table. for the table being
     updated.  (Bug #38691)

   * On ActiveState Perl, `mysql-test-run.pl --start-and-exit' started
     but did not exit.  (Bug #38629)

   * Stored procedures involving substrings could crash the server on
     certain platforms due to invalid memory reads.  (Bug #38469)

   * The server crashed if an argument to a stored procedure was a
     subquery that returned more than one row.  (Bug #37949)

   * When analyzing the possible index use cases, the server was
     incorrectly reusing an internal structure, leading to a server
     crash.  (Bug #37943)

   * A *Note `SELECT': select. with a `NULL NOT IN' condition
     containing a complex subquery from the same table as in the outer
     select caused an assertion failure.  (Bug #37894)

   * On a 32-bit server built without big tables support, the offset
     argument in a `LIMIT' clause might be truncated due to a 64-bit to
     32-bit cast.  (Bug #37075)

   * Host name values in SQL statements were not being checked for
     `'@'', which is illegal according to RFC952.  (Bug #35924)

   * *Note `mysql_install_db': mysql-install-db. failed on machines
     that had the host name set to `localhost'.  (Bug #35754)

   * Dynamic plugins failed to load on i5/OS.  (Bug #35743)

   * XA transaction rollbacks could result in corrupted transaction
     states and a server crash.  (Bug #28323)

   * The `Questions' status variable is intended as a count of
     statements sent by clients to the server, but was also counting
     statements executed within stored routines.  (Bug #24289)

   * For access to the *Note `INFORMATION_SCHEMA.VIEWS': views-table.
     table, the server did not check the `SHOW VIEW' and *Note
     `SELECT': select.  privileges, leading to inconsistency between
     output from that table and the *Note `SHOW CREATE VIEW':
     show-create-view.  statement.  (Bug #22763)

   * `mysqld_safe' would sometimes fail to remove the pid file for the
     old `mysql' process after a crash. As a result, the server would
     fail to start due to a false `A mysqld process already exists...'
     error.  (Bug #11122)


File: manual.info,  Node: news-5-0-70,  Next: news-5-0-68,  Prev: news-5-0-72,  Up: news-5-0-x

D.1.28 Changes in MySQL Enterprise 5.0.70 [MRU] (27 September 2008)
-------------------------------------------------------------------

This is a _Monthly Rapid Update_ release of the MySQL Enterprise Server
5.0.

This section documents all changes and bugfixes that have been applied
since the last MySQL Enterprise Server release (5.0.68).  If you would
like to receive more fine-grained and personalized _update alerts_
about fixes that are relevant to the version and features you use,
please consider subscribing to _MySQL Enterprise_ (a commercial MySQL
offering). For more details please see
http://www.mysql.com/products/enterprise/advisors.html.

*Functionality Added or Changed*

   * *Security Enhancement*: To enable stricter control over the
     location from which user-defined functions can be loaded, the
     `plugin_dir' system variable has been backported from MySQL 5.1.
     If the value is nonempty, user-defined function object files can
     be loaded only from the directory named by this variable. If the
     value is empty, the behavior that is used prior to the inclusion of
     `plugin_dir' applies: The UDF object files must be located in a
     directory that is searched by your system's dynamic linker.

     If the plugin directory is writable by the server, it may be
     possible for a user to write executable code to a file in the
     directory using *Note `SELECT ... INTO DUMPFILE': select. This can
     be prevented by making `plugin_dir' read only to the server or by
     setting `--secure-file-priv' to a directory where *Note `SELECT':
     select. writes can be made safely.  (Bug #37428)

*Bugs Fixed*

   * *Important Change*: *Security Fix*: Additional corrections were
     made for the symlink-related privilege problem originally
     addressed in MySQL 5.0.60. The original fix did not correctly
     handle the data directory path name if it contained symlinked
     directories in its path, and the check was made only at
     table-creation time, not at table-opening time later.  (Bug
     #32167, CVE-2008-2079) See also Bug #39277.

   * *Incompatible Change*: There were some problems using `DllMain()'
     hook functions on Windows that automatically do global and
     per-thread initialization for `libmysqld.dll':

        * Per-thread initialization: MySQL internally counts the number
          of active threads, which causes a delay in `my_end()' if not
          all threads have exited. But there are threads that can be
          started either by Windows internally (often in TCP/IP
          scenarios) or by users.  Those threads do not necessarily use
          `libmysql.dll' functionality but still contribute to the
          open-thread count. (One symptom is a five-second delay in
          times for PHP scripts to finish.)

        * Process-initialization: *Note `my_init()': my-init. calls
          `WSAStartup' that itself loads DLLs and can lead to a
          deadlock in the Windows loader.

     To correct these problems, DLL initialization code now is not
     invoked from `libmysql.dll' by default. To obtain the previous
     behavior (DLL initialization code will be called), set the
     `LIBMYSQL_DLLINIT' environment variable to any value. This
     variable exists only to prevent breakage of existing Windows-only
     applications that do not call *Note `mysql_thread_init()':
     mysql-thread-init. and work okay today. Use of `LIBMYSQL_DLLINIT'
     is discouraged and is removed in MySQL 6.0.  (Bug #37226, Bug
     #33031)

   * For a *Note `TIMESTAMP': datetime. column in an `InnoDB' table,
     testing the column with multiple conditions in the `WHERE' clause
     caused a server crash.  (Bug #39353)

   * Queries of the form `SELECT ... REGEXP BINARY NULL' could lead to
     a hung or crashed server.  (Bug #39021)

   * Statements of the form `INSERT ... SELECT .. ON DUPLICATE KEY
     UPDATE COL_NAME = DEFAULT' could result in a server crash.  (Bug
     #39002)

   * Repeated *Note `CREATE TABLE ... SELECT': create-table.
     statements, where the created table contained an `AUTO_INCREMENT'
     column, could lead to an assertion failure.  (Bug #38821)

   * A server crash or Valgrind warnings could result when a stored
     procedure selected from a view that referenced a function.  (Bug
     #38291)

   * Incorrect handling of aggregate functions when loose index scan
     was used caused a server crash.  (Bug #38195)

   * If a table has a `BIT NOT NULL' column `c1' with a length shorter
     than 8 bits and some additional `NOT NULL' columns `c2', ..., and a
     *Note `SELECT': select. query has a `WHERE' clause of the form
     `(c1 = CONSTANT) AND c2 ...', the query could return an unexpected
     result set.  (Bug #37799)

   * The `<=>' operator could return incorrect results when comparing
     `NULL' to *Note `DATE': datetime, *Note `TIME': time, or *Note
     `DATETIME': datetime. values.  (Bug #37526)

   * For a `MyISAM' table with `CHECKSUM = 1' and `ROW_FORMAT =
     DYNAMIC' table options, a data consistency check (maximum record
     length) could fail and cause the table to be marked as corrupted.
     (Bug #37310)

   * The `max_length' result set metadata value was calculated
     incorrectly under some circumstances.  (Bug #37301)

   * The `NO_BACKSLASH_ESCAPES' SQL mode was ignored for *Note `LOAD
     DATA INFILE': load-data. and `SELECT INTO ... OUTFILE'.  The
     setting is taken into account now.  (Bug #37114)

   * A query which had an `ORDER BY DESC' clause that is satisfied with
     a reverse range scan could cause a server crash for some specific
     CPU/compiler combinations.  (Bug #36639)

   * Dumping information about locks in use by sending a `SIGHUP'
     signal to the server or by invoking the *Note `mysqladmin debug':
     mysqladmin. command could lead to a server crash in debug builds
     or to undefined behavior in production builds.  (Bug #36579)

   * When the fractional part in a multiplication of *Note `DECIMAL':
     numeric-types. values overflowed, the server truncated the first
     operand rather than the longest. Now the server truncates so as to
     produce more precise multiplications.  (Bug #36270)

   * Changes to build files were made to enable the MySQL distribution
     to compile on Microsoft Visual C++ Express 2008.  (Bug #33907)

   * *Note `mysqldump': mysqldump. could fail to dump views containing
     a large number of columns.  (Bug #31434)

   * Several MySQL programs could fail if the `HOME' environment
     variable had an empty value.  (Bug #30394)

   * The `BUILD/check-cpu' build script failed if `gcc' had a different
     name (such as `gcc.real' on Debian).  (Bug #27526)


File: manual.info,  Node: news-5-0-68,  Next: news-5-0-67,  Prev: news-5-0-70,  Up: news-5-0-x

D.1.29 Changes in MySQL Enterprise 5.0.68 [MRU] (13 August 2008)
----------------------------------------------------------------

This is a _Monthly Rapid Update_ release of the MySQL Enterprise Server
5.0.

This section documents all changes and bugfixes that have been applied
since the last MySQL Enterprise Server release (5.0.66a).  If you would
like to receive more fine-grained and personalized _update alerts_
about fixes that are relevant to the version and features you use,
please consider subscribing to _MySQL Enterprise_ (a commercial MySQL
offering). For more details please see
http://www.mysql.com/products/enterprise/advisors.html.

*Bugs Fixed*

   * *Security Enhancement*: The server consumed excess memory while
     parsing statements with hundreds or thousands of nested boolean
     conditions (such as `OR (OR ... (OR ... ))'). This could lead to a
     server crash or incorrect statement execution, or cause other
     client statements to fail due to lack of memory. The latter result
     constitutes a denial of service.  (Bug #38296)

   * *Incompatible Change*: *Note `SHOW STATUS': show-status. took a
     lot of CPU time for calculating the value of the
     `Innodb_buffer_pool_pages_latched' status variable. Now this
     variable is calculated and included in the output of *Note `SHOW
     STATUS': show-status. only if the `UNIV_DEBUG' symbol is defined
     at MySQL build time.  (Bug #36600)

   * Server-side cursors were not initialized properly, which could
     cause a server crash.  (Bug #38486)

   * Queries containing a subquery with `DISTINCT' and `ORDER BY' could
     cause a server crash.  (Bug #38191)

   * For `InnoDB' tables, `ORDER BY ...  DESC' sometimes returned
     results in ascending order.  (Bug #37830)

   * Nesting of `IF()' inside of `SUM()' could cause an extreme server
     slowdown.  (Bug #37662)

   * If the server failed to expire binary log files at startup, it
     could crash.  (Bug #37027)

   * The `UUID()' function returned UUIDs with the wrong time; this was
     because the offset for the time part in UUIDs was miscalculated.
     (Bug #35848)

   * Freeing of an internal parser stack during parsing of complex
     stored programs caused a server crash.  (Bug #35577, Bug #37269,
     Bug #37228)

   * Index scans performed with the `sort_union()' access method
     returned wrong results, caused memory to be leaked, and caused
     temporary files to be deleted when the limit set by
     `sort_buffer_size' was reached.  (Bug #35477, Bug #35478)

   * If the server crashed with an `InnoDB' error due to unavailability
     of undo slots, errors could persist during rollback when the
     server was restarted: There are two `UNDO' slot caches (for *Note
     `INSERT': insert. and *Note `UPDATE': update.). If all slots end
     up in one of the slot caches, a request for a slot from the other
     slot cache would fail. This can happen if the request is for an
     *Note `UPDATE': update. slot and all slots are in the *Note
     `INSERT': insert. slot cache, or vice versa.  (Bug #35352)

   * For `InnoDB' tables, `ALTER TABLE DROP' failed if the name of the
     column to be dropped began with `foreign'.  (Bug #35220)

   * Using *Note `OPTIMIZE TABLE': optimize-table. as the first
     statement on an `InnoDB' table with an `AUTO_INCREMENT' column
     could cause a server crash.  (Bug #34286)

   * *Note `mysql_install_db': mysql-install-db. failed if the server
     was running with an SQL mode of `TRADITIONAL'. This program now
     resets the SQL mode internally to avoid this problem.  (Bug #34159)

   * Cached queries that used 256 or more tables were not properly
     cached, so that later query invalidation due to a *Note `TRUNCATE
     TABLE': truncate-table. for one of the tables caused the server to
     hang.  (Bug #33362)

   * *Note `mysql_upgrade': mysql-upgrade. attempted to use the `/proc'
     file system even on systems that do not have it.  (Bug #31605)

   * On NetWare, *Note `mysql_install_db': mysql-install-db. could
     appear to execute normally even if it failed to create the initial
     databases.  (Bug #30129)

   * The Serbian translation for the `ER_INCORRECT_GLOBAL_LOCAL_VAR'
     error was corrected.  (Bug #29738)

   * In some cases, the parser interpreted the `;' character as the end
     of input and misinterpreted stored program definitions.  (Bug
     #26030)

   * The *Note `FLUSH PRIVILEGES': flush. statement did not produce an
     error when it failed.  (Bug #21226)


File: manual.info,  Node: news-5-0-67,  Next: news-5-0-66sp1,  Prev: news-5-0-68,  Up: news-5-0-x

D.1.30 Changes in MySQL Community Server 5.0.67 (04 August 2008)
----------------------------------------------------------------

This is a bugfix release for the current MySQL Community Server
production release family. It replaces MySQL 5.0.51b.

*Functionality Added or Changed*

   * *Security Enhancement*: To enable stricter control over the
     location from which user-defined functions can be loaded, the
     `plugin_dir' system variable has been backported from MySQL 5.1.
     If the value is nonempty, user-defined function object files can
     be loaded only from the directory named by this variable. If the
     value is empty, the behavior that is used prior to the inclusion of
     `plugin_dir' applies: The UDF object files must be located in a
     directory that is searched by your system's dynamic linker.

     If the plugin directory is writable by the server, it may be
     possible for a user to write executable code to a file in the
     directory using *Note `SELECT ... INTO DUMPFILE': select. This can
     be prevented by making `plugin_dir' read only to the server or by
     setting `--secure-file-priv' to a directory where *Note `SELECT':
     select. writes can be made safely.  (Bug #37428)

   * *Important Change*: *Incompatible Change*: The `FEDERATED' storage
     engine is now disabled by default in the `.cnf' files shipped with
     MySQL distributions (`my-huge.cnf', `my-medium.cnf', and so
     forth). This affects server behavior only if you install one of
     these files.  (Bug #37069)

   * *Cluster API*: *Important Change*: Because
     `NDB_LE_MemoryUsage.page_size_kb' shows memory page sizes in bytes
     rather than kilobytes, it has been renamed to `page_size_bytes'.
     The name `page_size_kb' is now deprecated and thus subject to
     removal in a future release, although it currently remains
     supported for reasons of backward compatibility. See The
     `Ndb_logevent_type' Type
     (http://dev.mysql.com/doc/ndbapi/en/mgm-ndb-logevent-type.html),
     for more information about `NDB_LE_MemoryUsage'.  (Bug #30271)

   * *Important Change*: Some changes were made to *Note `CHECK TABLE
     ... FOR UPGRADE': check-table. and *Note `REPAIR TABLE':
     repair-table. with respect to detection and handling of tables
     with incompatible `.frm' files (files created with a different
     version of the MySQL server). These changes also affect *Note
     `mysqlcheck': mysqlcheck. because that program uses *Note `CHECK
     TABLE': check-table. and *Note `REPAIR TABLE': repair-table, and
     thus also *Note `mysql_upgrade': mysql-upgrade. because that
     program invokes *Note `mysqlcheck': mysqlcheck.

        * If your table was created by a different version of the MySQL
          server than the one you are currently running, *Note `CHECK
          TABLE ... FOR UPGRADE': check-table. indicates that the table
          has an `.frm' file with an incompatible version.  In this
          case, the result set returned by *Note `CHECK TABLE':
          check-table. contains a line with a `Msg_type' value of
          `error' and a `Msg_text' value of `Table upgrade required.
          Please do "REPAIR TABLE `TBL_NAME`" to fix it!'

        * *Note `REPAIR TABLE': repair-table. without `USE_FRM'
          upgrades the `.frm' file to the current version.

        * If you use `REPAIR TABLE ...USE_FRM' and your table was
          created by a different version of the MySQL server than the
          one you are currently running, *Note `REPAIR TABLE':
          repair-table. will not attempt to repair the table. In this
          case, the result set returned by *Note `REPAIR TABLE':
          repair-table. contains a line with a `Msg_type' value of
          `error' and a `Msg_text' value of `Failed repairing
          incompatible .FRM file'.

          Previously, use of `REPAIR TABLE ...USE_FRM' with a table
          created by a different version of the MySQL server risked the
          loss of all rows in the table.

     (Bug #36055)

   * *Note `mysql_upgrade': mysql-upgrade. now has a `--tmpdir' option
     to enable the location of temporary files to be specified.  (Bug
     #36469)

   * `mysql-test-run.pl' now supports `--client-bindir' and
     `--client-libdir' options for specifying the directory where
     client binaries and libraries are located.  (Bug #34995)

   * The *Note `ndbd': mysql-cluster-programs-ndbd. and *Note
     `ndb_mgmd': mysql-cluster-programs-ndb-mgmd. man pages have been
     reclassified from volume 1 to volume 8.  (Bug #34642)

   * For binary `.tar.gz' packages, *Note `mysqld': mysqld. and other
     binaries now are compiled with debugging symbols included to
     enable easier use with a debugger. If you do not need debugging
     symbols and are short on disk space, you can use `strip' to remove
     the symbols from the binaries.  (Bug #33252)

   * *Note `mysqldump': mysqldump. produces a `-- Dump completed on
     DATE' comment at the end of the dump if `--comments' is given. The
     date causes dump files for identical data take at different times
     to appear to be different. The new options `--dump-date' and
     `--skip-dump-date' control whether the date is added to the
     comment.  `--skip-dump-date' suppresses date printing. The default
     is `--dump-date' (include the date in the comment).  (Bug #31077)

   * `mysqltest' now has `mkdir' and `rmdir' commands for creating and
     removing directories.  (Bug #31004)

   * The `mysql_odbc_escape_string()' C API function has been removed.
     It has multi-byte character escaping issues, doesn't honor the
     `NO_BACKSLASH_ESCAPES' SQL mode and is not needed anymore by
     Connector/ODBC as of 3.51.17.  (Bug #29592) See also Bug #41728.

   * The default value of the `connect_timeout' system variable was
     increased from 5 to 10 seconds. This might help in cases where
     clients frequently encounter errors of the form `Lost connection
     to MySQL server at 'XXX', system error: ERRNO'.  (Bug #28359)

   * The use of `InnoDB' hash indexes now can be controlled by setting
     the new `innodb_adaptive_hash_index' system variable at server
     startup. By default, this variable is enabled. See *Note
     innodb-adaptive-hash::.

   * The argument for the `mysql-test-run.pl' `--do-test' and
     `--skip-test' options is now interpreted as a Perl regular
     expression if there is a pattern metacharacter in the argument
     value. This enables more flexible specification of which tests to
     perform or skip.

*Bugs Fixed*

   * *Performance*: `InnoDB' adaptive hash latches could be held too
     long during filesort operations, resulting in a server crash. Now
     the hash latch is released when a query on `InnoDB' tables
     performs a filesort. This eliminates the crash and may provide
     significant performance improvements on systems on which many
     queries using filesorts with temporary tables are being performed.
     (Bug #32149)

   * *Performance*: `InnoDB' had a race condition for an adaptive hash
     rw-lock waiting for an X-lock. This fix may also provide
     significant speed improvements on systems experiencing problems
     with contention for the adaptive hash index.  (Bug #29560)

   * *Important Change*: *Security Fix*: It was possible to circumvent
     privileges through the creation of `MyISAM' tables employing the
     `DATA DIRECTORY' and `INDEX DIRECTORY' options to overwrite
     existing table files in the MySQL data directory. Use of the MySQL
     data directory in `DATA DIRECTORY' and `INDEX DIRECTORY' path name
     is no longer permitted.

     *Note*:

     Additional fixes were made in MySQL 5.0.70.

     (Bug #32167, CVE-2008-2079) See also Bug #39277.

   * *Security Fix*: Three vulnerabilities in yaSSL versions 1.7.5 and
     earlier were discovered that could lead to a server crash or
     execution of unauthorized code. The exploit requires a server with
     yaSSL enabled and TCP/IP connections enabled, but does not require
     valid MySQL account credentials. The exploit does not apply to
     OpenSSL.

     *Warning*:

     The proof-of-concept exploit is freely available on the Internet.
     Everyone with a vulnerable MySQL configuration is advised to
     upgrade _immediately_.

     (Bug #33814, CVE-2008-0226, CVE-2008-0227)

   * *Security Fix*: Using *Note `RENAME TABLE': rename-table. against a
     table with explicit `DATA DIRECTORY' and `INDEX DIRECTORY' options
     can be used to overwrite system table information by replacing the
     symbolic link points. the file to which the symlink points.

     MySQL will now return an error when the file to which the symlink
     points already exists.  (Bug #32111, CVE-2007-5969)

   * *Security Fix*: *Note `ALTER VIEW': alter-view. retained the
     original `DEFINER' value, even when altered by another user, which
     could enable that user to gain the access rights of the view. Now
     *Note `ALTER VIEW': alter-view. is permitted only to the original
     definer or users with the `SUPER' privilege.  (Bug #29908)

   * *Security Fix*: When using a `FEDERATED' table, the local server
     could be forced to crash if the remote server returned a result
     with fewer columns than expected.  (Bug #29801)

   * *Security Enhancement*: It was possible to force an error message
     of excessive length which could lead to a buffer overflow. This
     has been made no longer possible as a security precaution.  (Bug
     #32707)

   * *Incompatible Change*: It was possible to use `FRAC_SECOND' as a
     synonym for `MICROSECOND' with `DATE_ADD()', `DATE_SUB()', and
     `INTERVAL'; now, using `FRAC_SECOND' with anything other than
     `TIMESTAMPADD()' or `TIMESTAMPDIFF()' produces a syntax error.

     It is now possible (and preferable) to use `MICROSECOND' with
     `TIMESTAMPADD()' and `TIMESTAMPDIFF()', and `FRAC_SECOND' is now
     deprecated.  (Bug #33834)

   * *Incompatible Change*: With `ONLY_FULL_GROUP_BY' SQL mode enabled,
     queries such as `SELECT a FROM t1 HAVING COUNT(*)>2' were not
     being rejected as they should have been.

     This fix results in the following behavior:

        * There is a check against mixing group and nongroup columns
          _only_ when `ONLY_FULL_GROUP_BY' is enabled.

        * This check is done both for the select list and for the
          `HAVING' clause if there is one.

     This behavior differs from previous versions as follows:

        * Previously, the `HAVING' clause was not checked when
          `ONLY_FULL_GROUP_BY' was enabled; now it is checked.

        * Previously, the select list was checked even when
          `ONLY_FULL_GROUP_BY' was not enabled; now it is checked only
          when `ONLY_FULL_GROUP_BY' is enabled.

     (Bug #31794)

   * *Incompatible Change*: The MySQL 5.0.50 patch for this bug was
     reverted because it changed the behavior of a General Availability
     MySQL release.  (Bug #30234) See also Bug #27525.

   * *Incompatible Change*: It was possible to create a view having a
     column whose name consisted of an empty string or space characters
     only.

     One result of this bug fix is that aliases for columns in the view
     `SELECT' statement are checked to ensure that they are legal
     column names. In particular, the length must be within the maximum
     column length of 64 characters, not the maximum alias length of
     256 characters. This can cause problems for replication or loading
     dump files. For additional information and workarounds, see *Note
     view-restrictions::.  (Bug #27695) See also Bug #31202.

   * *Incompatible Change*: Several type-preserving functions and
     operators returned an incorrect result type that does not match
     their argument types: `COALESCE()', `IF()', `IFNULL()', `LEAST()',
     `GREATEST()', `CASE'. These now aggregate using the precise SQL
     types of their arguments rather than the internal type. In
     addition, the result type of the `STR_TO_DATE()' function is now
     *Note `DATETIME': datetime. by default.  (Bug #27216)

   * *Incompatible Change*: It was possible for option files to be read
     twice at program startup, if some of the standard option file
     locations turned out to be the same directory. Now duplicates are
     removed from the list of files to be read.

     Also, users could not override system-wide settings using
     `~/.my.cnf' because `SYSCONFDIR/my.cnf' was read last. The latter
     file now is read earlier so that `~/.my.cnf' can override
     system-wide settings.

     The fix for this problem had a side effect such that on Unix,
     MySQL programs looked for options in `~/my.cnf' rather than the
     standard location of `~/.my.cnf'. That problem was addressed as
     Bug #38180.  (Bug #20748)

   * *Important Change*: *MySQL Cluster*: `AUTO_INCREMENT' columns had
     the following problems when used in *Note `NDB': mysql-cluster.
     tables:

        * The `AUTO_INCREMENT' counter was not updated correctly when
          such a column was updated.

        * `AUTO_INCREMENT' values were not prefetched beyond statement
          boundaries.

        * `AUTO_INCREMENT' values were not handled correctly with *Note
          `INSERT IGNORE': insert. statements.

        * After being set, `ndb_autoincrement_prefetch_sz' showed a
          value of 1, regardless of the value it had actually been set
          to.

     As part of this fix, the behavior of
     `ndb_autoincrement_prefetch_sz' has changed. Setting this to less
     than 32 no longer has any effect on prefetching within statements
     (where IDs are now always obtained in batches of 32 or more), but
     only between statements. The default value for this variable has
     also changed, and is now `1'.  (Bug #25176, Bug #31956, Bug #32055)

   * *Important Change*: *Replication*: When the master crashed during
     an update on a transactional table while in `autocommit' mode, the
     slave failed. This fix causes every transaction (including
     `autocommit' transactions) to be recorded in the binary log as
     starting with a *Note `BEGIN': commit. and ending with a *Note
     `COMMIT': commit. or *Note `ROLLBACK': commit.

     *Note*:

     The current fix does _not_ cause nontransactional changes to be
     wrapped in *Note `BEGIN': commit ...  *Note `COMMIT': commit. or
     *Note `BEGIN': commit ...  *Note `ROLLBACK': commit.  when written
     to the binary log. For this purpose, any statements affecting
     tables using a nontransactional storage engine such as *Note
     `MyISAM': myisam-storage-engine. are regarded as nontransactional,
     even when `autocommit' is enabled.

     (Bug #26395) See also Bug #29288, Bug #49522.

   * *Important Change*: The server no longer issues warnings for
     truncation of excess spaces for values inserted into *Note `CHAR':
     char. columns. This reverts a change in the previous release that
     caused warnings to be issued.  (Bug #30059)

   * *Important Change*: When installing MySQL on AIX 5.3, you must
     upgrade AIX to technology level 7 (5300-07) to ensure the required
     thread libraries are available.

   * *Replication*: *Important Note*: Network timeouts between the
     master and the slave could result in corruption of the relay log.
     This fix rectifies a long-standing replication issue when using
     unreliable networks, including replication over wide area networks
     such as the Internet. If you experience reliability issues and see
     many `You have an error in your SQL syntax' errors on replication
     slaves, we strongly recommend that you upgrade to a MySQL version
     which includes this fix.  (Bug #26489)

   * *MySQL Cluster*: When configured with *Note `NDB': mysql-cluster.
     support, MySQL failed to compile using `gcc' 4.3 on 64bit FreeBSD
     systems.  (Bug #34169)

   * *MySQL Cluster*: The failure of a DDL statement could sometimes
     lead to node failures when attempting to execute subsequent DDL
     statements.  (Bug #34160)

   * *MySQL Cluster*: Extremely long *Note `SELECT': select. statements
     (where the text of the statement was in excess of 50000
     characters) against *Note `NDB': mysql-cluster. tables returned
     empty results.  (Bug #34107)

   * *MySQL Cluster*: A periodic failure to flush the send buffer by the
     *Note `NDB': mysql-cluster. TCP transporter could cause a
     unnecessary delay of 10 ms between operations.  (Bug #34005)

   * *MySQL Cluster*: When all data and SQL nodes in the cluster were
     shut down abnormally (that is, other than by using `STOP' in the
     cluster management client), *Note `ndb_mgm':
     mysql-cluster-programs-ndb-mgm.  used excessive amounts of CPU.
     (Bug #33237)

   * *MySQL Cluster*: An improperly reset internal signal was observed
     as a hang when using events in the *Note `NDB': mysql-cluster. API
     but could result in various errors.  (Bug #33206)

   * *MySQL Cluster*: Incorrectly handled parameters could lead to a
     crash in the Transaction Coordinator during a node failure,
     causing other data nodes to fail.  (Bug #33168)

   * *MySQL Cluster*: The failure of a master node could lead to
     subsequent failures in local checkpointing.  (Bug #32160)

   * *MySQL Cluster*: An uninitialized variable in the *Note `NDB':
     mysql-cluster. storage engine code led to `AUTO_INCREMENT'
     failures when the server was compiled with `gcc' 4.2.1.  (Bug
     #31848) This regression was introduced by Bug #27437.

   * *MySQL Cluster*: An error with an `if' statement in
     `sql/ha_ndbcluster.cc' could potentially lead to an infinite loop
     in case of failure when working with `AUTO_INCREMENT' columns in
     *Note `NDB': mysql-cluster. tables.  (Bug #31810)

   * *MySQL Cluster*: The *Note `NDB': mysql-cluster. storage engine
     code was not safe for strict-alias optimization in `gcc' 4.2.1.
     (Bug #31761)

   * *MySQL Cluster*: Primary keys on variable-length columns (such as
     *Note `VARCHAR': char.) did not work correctly.  (Bug #31635)

   * *MySQL Cluster*: Transaction atomicity was sometimes not preserved
     between reads and inserts under high loads.  (Bug #31477)

   * *MySQL Cluster*: Numerous *Note `NDBCLUSTER': mysql-cluster. test
     failures occurred in builds compiled using `icc' on IA64 platforms.
     (Bug #31239)

   * *MySQL Cluster*: Transaction timeouts were not handled well in some
     circumstances, leading to excessive number of transactions being
     aborted unnecessarily.  (Bug #30379)

   * *MySQL Cluster*: Having tables with a great many columns could
     cause Cluster backups to fail.  (Bug #30172)

   * *MySQL Cluster*: Issuing an *Note `INSERT ... ON DUPLICATE KEY
     UPDATE': insert-on-duplicate. concurrently with or following a
     *Note `TRUNCATE TABLE': truncate-table. statement on an *Note
     `NDB': mysql-cluster. table failed with *Note `NDB':
     mysql-cluster. error 4350 `Transaction already aborted'.  (Bug
     #29851)

   * *MySQL Cluster*: In some cases, the cluster managment server
     logged entries multiple times following a restart of *Note
     `ndb_mgmd': mysql-cluster-programs-ndb-mgmd.  (Bug #29565)

   * *MySQL Cluster*: An interpreted program of sufficient size and
     complexity could cause all cluster data nodes to shut down due to
     buffer overruns.  (Bug #29390)

   * *MySQL Cluster*: It was possible in `config.ini' to define cluster
     nodes having node IDs greater than the maximum permitted value.
     (Bug #28298)

   * *MySQL Cluster*: `UPDATE IGNORE' could sometimes fail on *Note
     `NDB': mysql-cluster. tables due to the use of unitialized data
     when checking for duplicate keys to be ignored.  (Bug #25817)

   * *MySQL Cluster*: When inserting a row into an *Note `NDB':
     mysql-cluster.  table with a duplicate value for a nonprimary
     unique key, the error issued would reference the wrong key.

     This improves on an initial fix for this issue made in MySQL
     5.0.30 and MySQL 5.0.33 (Bug #21072)

   * *Replication*: Some kinds of internal errors, such as `Out of
     memory' errors, could cause the server to crash when replicating
     statements with user variables.

     certain internal errors.  (Bug #37150)

   * *Replication*: *Note `CREATE PROCEDURE': create-procedure. and
     *Note `CREATE FUNCTION': create-function. statements containing
     extended comments were not written to the binary log correctly,
     causing parse errors on the slave.  (Bug #36570) See also Bug
     #32575.

   * *Replication*: `insert_id' was not written to the binary log for
     inserts into `BLACKHOLE' tables.  (Bug #35178)

   * *Replication*: The character sets and collations used for constant
     identifiers in stored procedures were not replicated correctly.
     (Bug #34289)

   * *Replication*: A *Note `CREATE USER': create-user, *Note `DROP
     USER': drop-user, or *Note `RENAME USER': rename-user. statement
     that fails on the master, or that is a duplicate of any of these
     statements, is no longer written to the binlog; previously, either
     of these occurrences could cause the slave to fail.  (Bug #33862)
     See also Bug #29749.

   * *Replication*: *Note `SHOW BINLOG EVENTS': show-binlog-events.
     could fail when the binlog contained one or more events whose size
     was close to the value of `max_allowed_packet'.  (Bug #33413)

   * *Replication*: An extraneous *Note `ROLLBACK': commit.  statement
     was written to the binary log by a connection that did not use any
     transactional tables.  (Bug #33329)

   * *Replication*: When a stored routine or trigger, running on a
     master that used MySQL 5.0 or MySQL 5.1.11 or earlier, performed
     an insert on an `AUTO_INCREMENT' column, the `insert_id' value was
     not replicated correctly to a slave running MySQL 5.1.12 or later
     (including any MySQL 6.0 release).  (Bug #33029) See also Bug
     #19630.

   * *Replication*: *Note `CREATE VIEW': create-view. statements
     containing extended comments were not written to the binary log
     correctly, causing parse errors on the slave. Now, all comments are
     stripped from such statements before being written to the binary
     log.  (Bug #32575) See also Bug #36570.

   * *Replication*: SQL statements containing comments using `--'
     syntax were not replayable by *Note `mysqlbinlog': mysqlbinlog,
     even though such statements replicated correctly.  (Bug #32205)

   * *Replication*: It was possible for the name of the relay log file
     to exceed the amount of memory reserved for it, possibly leading
     to a crash of the server.  (Bug #31836) See also Bug #28597.

   * *Replication*: Corruption of log events caused the server to crash
     on 64-bit Linux systems having 4 GB or more of memory.  (Bug
     #31793)

   * *Replication*: Use of the `@@hostname' system variable in inserts
     in `mysql_system_tables_data.sql' did not replicate. The
     workaround is to select its value into a user variable (which does
     replicate) and insert that.  (Bug #31167)

   * *Replication*: *Note `STOP SLAVE': stop-slave. did not stop
     connection attempts properly. If the I/O slave thread was
     attempting to connect, *Note `STOP SLAVE': stop-slave.  waited for
     the attempt to finish, sometimes for a long period of time, rather
     than stopping the slave immediately.  (Bug #31024) See also Bug
     #30932.

   * *Replication*: Issuing a *Note `DROP VIEW': drop-view. statement
     caused replication to fail if the view did not actually exist.
     (Bug #30998)

   * *Replication*: One thread could read uninitialized memory from the
     stack of another thread. This issue was only known to occur in a
     *Note `mysqld': mysqld. process acting as both a master and a
     slave.  (Bug #30752)

   * *Replication*: Replication of *Note `LOAD DATA INFILE': load-data.
     could fail when `read_buffer_size' was larger than
     `max_allowed_packet'.  (Bug #30435)

   * *Replication*: Setting `server_id' did not update its value for
     the current session.  (Bug #28908)

   * *Replication*: Due a previous change in how the default name and
     location of the binary log file were determined, replication failed
     following some upgrades.  (Bug #28597, Bug #28603) See also Bug
     #31836.

     This regression was introduced by Bug #20166.

   * *Replication*: `MASTER_POS_WAIT()' did not return `NULL' when the
     server was not a slave.  (Bug #26622)

   * *Replication*: Stored procedures having *Note `BIT': numeric-types.
     parameters were not replicated correctly.  (Bug #26199)

   * *Replication*: Issuing *Note `SHOW SLAVE STATUS':
     show-slave-status. as *Note `mysqld': mysqld. was shutting down
     could cause a crash.  (Bug #26000)

   * *Replication*: An *Note `UPDATE': update. statement using a stored
     function that modified a nontransactional table was not logged if
     it failed. This caused the copy of the nontransactional table on
     the master have a row that the copy on the slave did not.

     In addition, when an *Note `INSERT ... ON DUPLICATE KEY UPDATE':
     insert-on-duplicate. statement encountered a duplicate key
     constraint, but the *Note `UPDATE': update. did not actually change
     any data, the statement was not logged. As a result of this fix,
     such statements are now treated the same for logging purposes as
     other *Note `UPDATE': update. statements, and so are written to
     the binary log.  (Bug #23333) See also Bug #12713.

   * *Replication*: The nonspecific error message `Wrong parameters to
     function register_slave' resulted when *Note `START SLAVE':
     start-slave. failed to register on the master due to excess length
     of any the slave server options `--report-host', `--report-user',
     or `--report-password'. An error message specific to each of these
     options is now returned in such cases. The new error messages are:

        * `Failed to register slave: too long 'report-host''

        * `Failed to register slave: too long 'report-user''

        * `Failed to register slave; too long 'report-password''

     (Bug #22989) See also Bug #19328.

   * *Replication*: A replication slave sometimes failed to reconnect
     because it was unable to run *Note `SHOW SLAVE HOSTS':
     show-slave-hosts.  It was not necessary to run this statement on
     slaves (since the master should track connection IDs), and the
     execution of this statement by slaves was removed.  (Bug #21132)
     See also Bug #13963, Bug #21869.

   * *Replication*: `PURGE BINARY LOGS TO' and `PURGE BINARY LOGS
     BEFORE' did not handle missing binary log files correctly or in
     the same way. Now for both of these statements, if any files
     listed in the `.index' file are missing from the file system, the
     statement fails with an error.  (Bug #18199, Bug #18453)

   * *Replication*: `START SLAVE UNTIL MASTER_LOG_POS=POSITION' issued
     on a slave that was using `--log-slave-updates' and that was
     involved in circular replication would cause the slave to run and
     stop one event later than that specified by the value of POSITION.
     (Bug #13861)

   * *Cluster API*: When reading a `BIT(64)' value using
     `NdbOperation:getValue()', 12 bytes were written to the buffer
     rather than the expected 8 bytes.  (Bug #33750)

   * The fix for Bug #20748 caused a problem such that on Unix, MySQL
     programs looked for options in `~/my.cnf' rather than the standard
     location of `~/.my.cnf'.  (Bug #38180)

   * The fix for Bug #33812 had the side effect of causing the *Note
     `mysql': mysql. client not to be able to read some dump files
     produced with *Note `mysqldump': mysqldump. To address this, that
     fix was reverted.  (Bug #38158)

   * Some binary distributions had a duplicate `-64bit' suffix in the
     file name.  (Bug #37623)

   * On Windows 64-bit systems, temporary variables of `long' types
     were used to store `ulong' values, causing key cache
     initialization to receive distorted parameters. The effect was
     that setting `key_buffer_size' to values of 2GB or more caused
     memory exhaustion to due allocation of too much memory.  (Bug
     #36705)

   * Multiple-table *Note `UPDATE': update. statements that used a
     temporary table could fail to update all qualifying rows or fail
     with a spurious duplicate-key error.  (Bug #36676)

   * A `REGEXP' match could return incorrect rows when the previous row
     matched the expression and used `CONCAT()' with an empty string.
     (Bug #36488)

   * `mysqltest' ignored the value of `--tmpdir' in one place.  (Bug
     #36465)

   * The *Note `mysql': mysql. client failed to recognize comment lines
     consisting of `--' followed by a newline.  (Bug #36244)

   * Conversion of a `FLOAT ZEROFILL' value to string could cause a
     server crash if the value was `NULL'.  (Bug #36139)

   * On Windows, the installer attempted to use JScript to determine
     whether the target data directory already existed. On Windows
     Vista x64, this resulted in an error because the installer was
     attempting to run the JScript in a 32-bit engine, which wasn't
     registered on Vista. The installer no longer uses JScript but
     instead relies on a native WiX command.  (Bug #36103)

   * An error in calculation of the precision of zero-length items
     (such as `NULL') caused a server crash for queries that employed
     temporary tables.  (Bug #36023)

   * For *Note `EXPLAIN EXTENDED': explain, execution of an uncorrelated
     `IN' subquery caused a crash if the subquery required a temporary
     table for its execution.  (Bug #36011)

   * The server crashed inside `NOT IN' subqueries with an impossible
     `WHERE' or `HAVING' clause, such as `NOT IN (SELECT ... FROM t1,
     t2, ... WHERE 0)'.  (Bug #36005)

   * Grouping or ordering of long values in unindexed *Note `BLOB':
     blob. or *Note `TEXT': blob. columns with the `gbk' or `big5'
     character set crashed the server.  (Bug #35993)

   * `SET GLOBAL debug=''' resulted in a Valgrind warning in
     `DbugParse()', which was reading beyond the end of the control
     string.  (Bug #35986)

   * An empty bit-string literal (`b''') caused a server crash. Now the
     value is parsed as an empty bit value (which is treated as an
     empty string in string context or 0 in numeric context).  (Bug
     #35658)

   * *Note `mysqlbinlog': mysqlbinlog. left temporary files on the disk
     after shutdown, leading to the pollution of the temporary
     directory, which eventually caused *Note `mysqlbinlog':
     mysqlbinlog. to fail. This caused problems in testing and other
     situations where *Note `mysqlbinlog': mysqlbinlog. might be
     invoked many times in a relatively short period of time.  (Bug
     #35543)

   * There was a memory leak when connecting to a `FEDERATED' table
     using a connection string that had a host value of `localhost' or
     omitted the host and a port value of `0' or omitted the port.
     (Bug #35509)

   * The code for detecting a byte order mark (BOM) caused *Note
     `mysql': mysql. to crash for empty input.  (Bug #35480)

   * Using *Note `LOAD DATA INFILE': load-data. with a view could crash
     the server.  (Bug #35469)

   * The combination of `GROUP_CONCAT()', `DISTINCT', and `LEFT JOIN'
     could crash the server when the right table is empty.  (Bug #35298)

   * When a view containing a reference to `DUAL' was created, the
     reference was removed when the definition was stored, causing some
     queries against the view to fail with invalid SQL syntax errors.
     (Bug #35193)

   * Debugging symbols were missing for some executables in Windows
     binary distributions.  (Bug #35104)

   * A query that performed a `ref_or_null' join where the second table
     used a key having one or columns that could be `NULL' and had a
     column value that was `NULL' caused the server to crash.  (Bug
     #34945) This regression was introduced by Bug #12144.

   * Some binaries produced stack corruption messages due to being
     built with versions of `bison' older than 2.1.  Builds are now
     created using `bison' 2.3.  (Bug #34926)

   * *Note `mysqldump': mysqldump. failed to return an error code when
     using the `--master-data' option without binary logging being
     enabled on the server.  (Bug #34909)

   * Under some circumstances, the value of *Note `mysql_insert_id()':
     mysql-insert-id. following a `SELECT ... INSERT' statement could
     return an incorrect value. This could happen when the last `SELECT
     ... INSERT' did not involve an `AUTO_INCREMENT' column, but the
     value of *Note `mysql_insert_id()': mysql-insert-id. was changed by
     some previous statements.  (Bug #34889)

   * Table and database names were mixed up in some places of the
     subquery transformation procedure. This could affect debugging
     trace output and further extensions of that procedure.  (Bug
     #34830)

   * A malformed URL used for a `FEDERATED' table's `CONNECTION' option
     value in a *Note `CREATE TABLE': create-table. statement was not
     handled correctly and could crash the server.  (Bug #34788)

   * Queries such as `SELECT ROW(1, 2) IN (SELECT t1.a, 2) FROM t1
     GROUP BY t1.a' (combining row constructors and subqueries in the
     `FROM' clause) could lead to assertion failure or unexpected error
     messages.  (Bug #34763)

   * Using `NAME_CONST()' with a negative number and an aggregate
     function caused MySQL to crash. This could also have a negative
     impact on replication.  (Bug #34749)

   * A memory-handling error associated with use of `GROUP_CONCAT()' in
     subqueries could result in a server crash.  (Bug #34747)

   * For an indexed integer column COL_NAME and a value N that is one
     greater than the maximum value permitted for the data type of
     COL_NAME, conditions of the form `WHERE COL_NAME < N' failed to
     return rows where the value of COL_NAME is `N - 1'.  (Bug #34731)

   * Executing a *Note `TRUNCATE TABLE': truncate-table.  statement on
     a table having both a foreign key reference and a `DELETE' trigger
     crashed the server.  (Bug #34643)

   * Some subqueries using an expression that included an aggregate
     function could fail or in some cases lead to a crash of the server.
     (Bug #34620)

   * A server crash could occur if `INFORMATION_SCHEMA' tables built in
     memory were swapped out to disk during query execution.  (Bug
     #34529)

   * `CAST(AVG(ARG) AS DECIMAL)' produced incorrect results for
     non-*Note `DECIMAL': numeric-types. arguments.  (Bug #34512)

   * *Note `mysql_explain_log': mysql-explain-log. concatenated
     multiple-line statements, causing malformed results for statements
     that contained SQL comments beginning with `--'.  (Bug #34339)

   * Executing an *Note `ALTER VIEW': alter-view. statement on a table
     crashed the server.  (Bug #34337)

   * Several additional configuration scripts in the `BUILD' directory
     now are included in source distributions. These may be useful for
     users who wish to build MySQL from source. (See *Note
     installing-development-tree::, for information about what they do.)
     (Bug #34291)

   * Under some conditions, a `SET GLOBAL innodb_commit_concurrency' or
     `SET GLOBAL innodb_autoextend_increment' statement could fail.
     (Bug #34223)

   * *Note `mysqldump': mysqldump. attempts to set the
     `character_set_results' system variable after connecting to the
     server. This failed for pre-4.1 servers that have no such
     variable, but *Note `mysqldump': mysqldump. did not account for
     this and 1) failed to dump database contents; 2) failed to produce
     any error message alerting the user to the problem.  (Bug #34192)

   * *Note `mysql_install_db': mysql-install-db. failed if the server
     was running with an SQL mode of `TRADITIONAL'. This program now
     resets the SQL mode internally to avoid this problem.  (Bug #34159)

   * For a `FEDERATED' table with an index on a nullable column,
     accessing the table could crash a server, return an incorrect
     result set, or return `ERROR 1030 (HY000): Got error 1430 from
     storage engine'.  (Bug #33946)

   * Passing anything other than an integer argument to a `LIMIT'
     clause in a prepared statement would fail. (This limitation was
     introduced to avoid replication problems; for example, replicating
     the statement with a string argument would cause a parse failure
     in the slave). Now, arguments to the `LIMIT' clause are converted
     to integer values, and these converted values are used when
     logging the statement.  (Bug #33851)

   * An internal buffer in *Note `mysql': mysql. was too short.
     Overextending it could cause stack problems or segmentation
     violations on some architectures. (This is not a problem that
     could be exploited to run arbitrary code.)  (Bug #33841)

   * A query using `WHERE (column1='STRING1' AND column2=CONSTANT1) OR
     (column1='STRING2' AND column2=CONSTANT2)', where `col1' used a
     binary collation and STRING1 matched STRING2 except for case,
     failed to match any records even when matches were found by a
     query using the equivalent clause `WHERE column2=CONSTANT1 OR
     column2=CONSTANT2'.  (Bug #33833)

   * The *Note `mysql': mysql. client incorrectly parsed statements
     containing the word `delimiter' in mid-statement.

     The fix for this bug had the side effect of causing the problem
     reported in Bug #38158, so it was reverted in MySQL 5.0.67.  (Bug
     #33812)

   * Large unsigned integers were improperly handled for prepared
     statements, resulting in truncation or conversion to negative
     numbers.  (Bug #33798)

   * Reuse of prepared statements could cause a memory leak in the
     embedded server.  (Bug #33796)

   * The server crashed when executing a query that had a subquery
     containing an equality X=Y where Y referred to a named select list
     expression from the parent select. The server crashed when trying
     to use the X=Y equality for `ref'-based access.  (Bug #33794)

   * Some queries using a combination of `IN', `CONCAT()', and an
     implicit type conversion could return an incorrect result.  (Bug
     #33764)

   * In some cases a query that produced a result set when using `ORDER
     BY ASC' did not return any results when this was changed to `ORDER
     BY DESC'.  (Bug #33758)

   * Disabling concurrent inserts caused some cacheable queries not to
     be saved in the query cache.  (Bug #33756)

   * Use of uninitialized memory for `filesort' in a subquery caused a
     server crash.  (Bug #33675)

   * The server could crash when *Note `REPEAT': repeat-statement.  or
     another control instruction was used in conjunction with labels
     and a *Note `LEAVE': leave-statement.  instruction.  (Bug #33618)

   * The parser permitted control structures in compound statements to
     have mismatched beginning and ending labels.  (Bug #33618)

   * `make_binary_distribution' passed the `--print-libgcc-file' option
     to the C compiler, but this does not work with the `ICC' compiler.
     (Bug #33536)

   * Certain combinations of views, subselects with outer references
     and stored routines or triggers could cause the server to crash.
     (Bug #33389)

   * `SET GLOBAL myisam_max_sort_file_size=DEFAULT' set
     `myisam_max_sort_file_size' to an incorrect value.  (Bug #33382)
     See also Bug #31177.

   * `SLEEP(0)' failed to return on 64-bit Mac OS X due to a bug in
     `pthread_cond_timedwait()'.  (Bug #33304)

   * *Note `CREATE TABLE ... SELECT': create-table. created tables that
     for date columns used the obsolete `Field_date' type instead of
     `Field_newdate'.  (Bug #33256)

   * Granting the `UPDATE' privilege on one column of a view caused the
     server to crash.  (Bug #33201)

   * For *Note `DECIMAL': numeric-types. columns used with the
     `ROUND(X,D)' or `TRUNCATE(X,D)' function with a nonconstant value
     of D, adding an `ORDER BY' for the function result produced
     misordered output.  (Bug #33143) See also Bug #33402, Bug #30617.

   * Some valid *Note `SELECT': select. statements could not be used as
     views due to incorrect column reference resolution.  (Bug #33133)

   * The fix for Bug #11230 and Bug #26215 introduced a significant
     input-parsing slowdown for the *Note `mysql': mysql. client.  This
     has been corrected.  (Bug #33057)

   * When MySQL was built with OpenSSL, the SSL library was not
     properly initialized with information of which endpoint it was
     (server or client), causing connection failures.  (Bug #33050)

   * Under some circumstances a combination of aggregate functions and
     `GROUP BY' in a *Note `SELECT': select. query over a view could
     lead to incorrect calculation of the result type of the aggregate
     function. This in turn could lead to incorrect results, or to
     crashes on debug builds of the server.  (Bug #33049)

   * For `DISTINCT' queries, MySQL 4.0 and 4.1 stopped reading joined
     tables as soon as the first matching row was found. However, this
     optimization was lost in MySQL 5.0, which instead read all
     matching rows. This fix for this regression may result in a major
     improvement in performance for `DISTINCT' queries in cases where
     many rows match.  (Bug #32942)

   * The server was built even when `configure' was run with the
     `--without-server' option.  (Bug #32898) See also Bug #23973.

   * Repeated creation and deletion of views within prepared statements
     could eventually crash the server.  (Bug #32890) See also Bug
     #34587.

   * *Note `UNION': union. constructs cannot contain *Note `SELECT ...
     INTO': select. except in the final *Note `SELECT': select.
     However, if a *Note `UNION': union. was used in a subquery and an
     `INTO' clause appeared in the top-level query, the parser
     interpreted it as having appeared in the *Note `UNION': union. and
     raised an error.  (Bug #32858)

   * The correct data type for a `NULL' column resulting from a *Note
     `UNION': union. could be determined incorrectly in some cases: 1)
     Not correctly inferred as `NULL' depending on the number of
     selects; 2) Not inferred correctly as `NULL' if one select used a
     subquery.  (Bug #32848)

   * An `ORDER BY' query using `IS NULL' in the `WHERE' clause did not
     return correct results.  (Bug #32815)

   * For queries containing `GROUP_CONCAT(DISTINCT COL_LIST ORDER BY
     COL_LIST)', there was a limitation that the `DISTINCT' columns had
     to be the same as `ORDER BY' columns. Incorrect results could be
     returned if this was not true.  (Bug #32798)

   * Incorrect assertions could cause a server crash for `DELETE'
     triggers for transactional tables.  (Bug #32790)

   * The `LAST_DAY()' function returns a *Note `DATE': datetime. value,
     but internally the value did not have the time fields zeroed and
     calculations involving the value could return incorrect results.
     (Bug #32770)

   * Use of the `cp932' character set with `CAST()' in an `ORDER BY'
     clause could cause a server crash.  (Bug #32726)

   * Inserting strings with a common prefix into a table that used the
     `ucs2' character set corrupted the table.  (Bug #32705)

   * A subquery using an `IS NULL' check of a column defined as `NOT
     NULL' in a table used in the `FROM' clause of the outer query
     produced an invalid result.  (Bug #32694)

   * Specifying a nonexistent column for an *Note `INSERT DELAYED':
     insert-delayed. statement caused a server crash rather than
     producing an error.  (Bug #32676)

   * Use of `CLIENT_MULTI_QUERIES' caused `libmysqld' to crash.  (Bug
     #32624)

   * The `INTERVAL()' function incorrectly handled `NULL' values in the
     value list.  (Bug #32560)

   * Use of a `NULL'-returning `GROUP BY' expression in conjunction
     with `WITH ROLLUP' could cause a server crash.  (Bug #32558) See
     also Bug #31095.

   * A `SELECT ... GROUP BY BIT_COLUMN' query failed with an assertion
     if the length of the *Note `BIT': numeric-types. column used for
     the `GROUP BY' was not an integer multiple of 8.  (Bug #32556)

   * Using `SELECT INTO OUTFILE' with 8-bit `ENCLOSED BY' characters
     led to corrupted data when the data was reloaded using LOAD DATA
     INFILE. This was because `SELECT INTO OUTFILE' failed to escape
     the 8-bit characters.  (Bug #32533)

   * For *Note `FLUSH TABLES WITH READ LOCK': flush, the server failed
     to properly detect write-locked tables when running with
     low-priority updates, resulting in a crash or deadlock.  (Bug
     #32528)

   * A build problem introduced in MySQL 5.0.52 was resolved: The x86
     32-bit Intel `icc'-compiled server binary had unwanted dependences
     on Intel `icc' runtime libraries.  (Bug #32514)

   * Queries using `LIKE' on tables having indexed *Note `CHAR': char.
     columns using either of the `eucjpms' or `ujis' character sets did
     not return correct results.  (Bug #32510)

   * The rules for valid column names were being applied differently
     for base tables and views.  (Bug #32496)

   * Sending several *Note `KILL QUERY': kill. statements to target a
     connection running `SELECT SLEEP()' could freeze the server.  (Bug
     #32436)

   * `ssl-cipher' values in option files were not being read by
     `libmysqlclient'.  (Bug #32429)

   * Repeated execution of a query containing a *Note `CASE':
     case-statement.  expression and numerous `AND' and `OR' relations
     could crash the server. The root cause of the issue was determined
     to be that the internal `SEL_ARG' structure was not properly
     initialized when created.  (Bug #32403)

   * Referencing within a subquery an alias used in the *Note `SELECT':
     select. list of the outer query was incorrectly permitted.  (Bug
     #32400)

   * An `ORDER BY' query on a view created using a `FEDERATED' table as
     a base table caused the server to crash.  (Bug #32374)

   * Comparison of a `BIGINT NOT NULL' column with a constant
     arithmetic expression that evaluated to NULL mistakenly caused the
     error `Column '...' cannot be null' (error 1048).  (Bug #32335)

   * Assigning a 65,536-byte string to a *Note `TEXT': blob. column
     (which can hold a maximum of 65,535 bytes) resulted in truncation
     without a warning. Now a truncation warning is generated.  (Bug
     #32282)

   * `MIN()' and `MAX()' could return incorrect results when an index
     was present if a loose index scan was used.  (Bug #32268)

   * Executing a prepared statement associated with a materialized
     cursor sent to the client a metadata packet with incorrect table
     and database names. The problem occurred because the server sent
     the name of the temporary table used by the cursor instead of the
     table name of the original table.

     The same problem occurred when selecting from a view, in which
     case the name of the table name was sent, rather than the name of
     the view.  (Bug #32265)

   * Memory corruption could occur due to large index map in `Range
     checked for each record' status reported by *Note `EXPLAIN
     SELECT': explain. The problem was based in an incorrectly
     calculated length of the buffer used to store a hexadecimal
     representation of an index map, which could result in buffer
     overrun and stack corruption under some circumstances.  (Bug
     #32241)

   * Various test program cleanups were made: 1) `mytest' and
     `libmysqltest' were removed. 2) `bug25714' displays an error
     message when invoked with incorrect arguments or the `--help'
     option. 3) `mysql_client_test' exits cleanly with a proper error
     status.  (Bug #32221)

   * The default grant tables on Windows contained information for host
     `production.mysql.com', which should not be there.  (Bug #32219)

   * Under certain conditions, the presence of a `GROUP BY' clause
     could cause an `ORDER BY' clause to be ignored.  (Bug #32202)

   * For comparisons of the form DATE_COL OP DATETIME_CONST (where OP is
     `=', `<', `>', `<=', or `>='), the comparison is done using *Note
     `DATETIME': datetime. values, per the fix for Bug #27590. However
     that fix caused any index on DATE_COL not to be used and
     compromised performance. Now the index is used again.  (Bug #32198)

   * *Note `DATETIME': datetime. arguments specified in numeric form
     were treated by `DATE_ADD()' as *Note `DATE': datetime. values.
     (Bug #32180)

   * `InnoDB' does not support `SPATIAL' indexes, but could crash when
     asked to handle one. Now an error is returned.  (Bug #32125)

   * The server crashed on optimizations involving a join of *Note
     `INT': numeric-types. and *Note `MEDIUMINT': numeric-types.
     columns and a system variable in the `WHERE' clause.  (Bug #32103)

   * *Note `SHOW STATUS': show-status. caused a server crash if
     `InnoDB' had not been initialized.  (Bug #32083)

   * With `lower_case_table_names' set, `CREATE TABLE LIKE' was treated
     differently by `libmysqld' than by the nonembedded server.  (Bug
     #32063)

   * Within a subquery, *Note `UNION': union. was handled differently
     than at the top level, which could result in incorrect results or
     a server crash.  (Bug #32036, Bug #32051)

   * User-defined functions are not loaded if the server is started
     with the `--skip-grant-tables' option, but the server did not
     properly handle this case and issued an `Out of memory' error
     message instead.  (Bug #32020)

   * `HOUR()', `MINUTE()', and `SECOND()' could return nonzero values
     for *Note `DATE': datetime. arguments.  (Bug #31990)

   * A column with malformed multi-byte characters could cause the
     full-text parser to go into an infinite loop.  (Bug #31950)

   * Changing the SQL mode to cause dates with `zero' parts to be
     considered invalid (such as `'1000-00-00'') could result in
     indexed and nonindexed searches returning different results for a
     column that contained such dates.  (Bug #31928)

   * Queries testing numeric constants containing leading zeros against
     `ZEROFILL' columns were not evaluated correctly.  (Bug #31887)

   * In debug builds, testing the result of an `IN' subquery against
     `NULL' caused an assertion failure.  (Bug #31884)

   * `mysql-test-run.pl' sometimes set up test scenarios in which the
     same port number was passed to multiple servers, causing one of
     them to be unable to start.  (Bug #31880)

   * Comparison results for `BETWEEN' were different from those for
     operators like `<' and `>' for *Note `DATETIME': datetime.-like
     values with trailing extra characters such as `'2007-10-01 00:00:00
     GMT-6''. `BETWEEN' treated the values as *Note `DATETIME':
     datetime, whereas the other operators performed a binary-string
     comparison. Now they all uniformly use a *Note `DATETIME':
     datetime.  comparison, but generate warnings for values with
     trailing garbage.  (Bug #31800)

   * Name resolution for correlated subqueries and `HAVING' clauses
     failed to distinguish which of two was being performed when there
     was a reference to an outer aliased field. This could result in
     error messages about a `HAVING' clause for queries that had no such
     clause.  (Bug #31797)

   * If an error occurred during file creation, the server sometimes
     did not remove the file, resulting in an unused file in the file
     system.  (Bug #31781)

   * The server could crash during `filesort' for `ORDER BY' based on
     expressions with `INET_NTOA()' or `OCT()' if those functions
     returned `NULL'.  (Bug #31758)

   * The *Note `mysqld': mysqld. crash handler failed on Windows.  (Bug
     #31745)

   * For a fatal error during a filesort in `find_all_keys()', the
     error was returned without the necessary handler uninitialization,
     causing an assertion failure.  (Bug #31742)

   * The examined-rows count was not incremented for `const' queries.
     (Bug #31700)

   * The *Note `mysql_change_user()': mysql-change-user. C API function
     was subject to buffer overflow.  (Bug #31669)

   * For *Note `SELECT ... INTO OUTFILE': select, if the `ENCLOSED BY'
     string is empty and the `FIELDS TERMINATED BY' string started with
     a special character (one of `n', `t', `r', `b', `0', `Z', or `N'),
     every occurrence of the character within field values would be
     duplicated.  (Bug #31663)

   * *Note `SHOW COLUMNS': show-columns. and *Note `DESCRIBE':
     describe. displayed `null' as the column type for a view with no
     valid definer. This caused *Note `mysqldump': mysqldump. to
     produce a nonreloadable dump file for the view.  (Bug #31662)

   * The *Note `mysqlbug': mysqlbug. script did not include the correct
     values of `CFLAGS' and `CXXFLAGS' that were used to configure the
     distribution.  (Bug #31644)

   * `ucs2' does not work as a client character set, but attempts to
     use it as such were not rejected. Now `character_set_client'
     cannot be set to `ucs2'. This also affects statements such as `SET
     NAMES' and `SET CHARACTER SET'.  (Bug #31615)

   * The server returned the error message `Out of memory; restart
     server and try again' when the actual problem was that the sort
     buffer was too small. Now an appropriate error message is returned
     in such cases.  (Bug #31590)

   * A buffer used when setting variables was not dimensioned to
     accommodate the trailing `'\0'' byte, so a single-byte buffer
     overrun was possible.  (Bug #31588)

   * `HAVING' could treat lettercase of table aliases incorrectly if
     `lower_case_table_names' was enabled.  (Bug #31562)

   * The fix for Bug #24989 introduced a problem such that a `NULL'
     thread handler could be used during a rollback operation. This
     problem is unlikely to be seen in practice.  (Bug #31517)

   * Killing a `CREATE TABLE ... LIKE' statement that was waiting for a
     name lock caused a server crash. When the statement was killed,
     the server attempted to release locks that were not held.  (Bug
     #31479)

   * The length of the result from `IFNULL()' could be calculated
     incorrectly because the sign of the result was not taken into
     account.  (Bug #31471)

   * Queries that used the `ref' access method or index-based subquery
     execution over indexes that have *Note `DECIMAL': numeric-types.
     columns could fail with an error `Column COL_NAME cannot be null'.
     (Bug #31450)

   * `SELECT 1 REGEX NULL' caused an assertion failure for debug
     servers.  (Bug #31440)

   * Executing `RENAME' while tables were open for use with *Note
     `HANDLER': handler. statements could cause a server crash.  (Bug
     #31409)

   * `mysql-test-run.pl' tried to create files in a directory where it
     could not be expected to have write permission. `mysqltest' created
     `.reject' files in a directory other than the one where test
     results go.  (Bug #31398)

   * *Note `DROP USER': drop-user. caused an increase in memory usage.
     (Bug #31347)

   * For an almost-full `MyISAM' table, an insert that failed could
     leave the table in a corrupt state.  (Bug #31305)

   * *Note `myisamchk --unpack': myisamchk. could corrupt a table that
     when unpacked has static (fixed-length) row format.  (Bug #31277)

   * `CONVERT(VAL, DATETIME)' would fail on invalid input, but
     processing was not aborted for the `WHERE' clause, leading to a
     server crash.  (Bug #31253)

   * Allocation of an insufficiently large group-by buffer following
     creation of a temporary table could lead to a server crash.  (Bug
     #31249)

   * Use of `DECIMAL(N, N) ZEROFILL' in `GROUP_CONCAT()' could cause a
     server crash.  (Bug #31227)

   * When sorting privilege table rows, the server treated escaped
     wildcard characters (`\%' and `\_') the same as unescaped wildcard
     characters (`%' and `_'), resulting in incorrect row ordering.
     (Bug #31194)

   * Server variables could not be set to their current values on Linux
     platforms.  (Bug #31177) See also Bug #6958.

   * With small values of `myisam_sort_buffer_size', *Note `REPAIR
     TABLE': repair-table. for `MyISAM' tables could cause a server
     crash.  (Bug #31174)

   * If `MAKETIME()' returned `NULL' when used in an `ORDER BY' that
     was evaluated using `filesort', a server crash could result.  (Bug
     #31160)

   * Full-text searches on `ucs2' columns caused a server crash.
     (`FULLTEXT' indexes on `ucs2' columns cannot be used, but it
     should be possible to perform `IN BOOLEAN MODE' searches on `ucs2'
     columns without a crash.)  (Bug #31159)

   * Data in *Note `BLOB': blob. or `GEOMETRY' columns could be cropped
     when performing a *Note `UNION': union. query.  (Bug #31158)

   * An assertion designed to detect a bug in the `ROLLUP'
     implementation would incorrectly be triggered when used in a
     subquery context with noncacheable statements.  (Bug #31156)

   * Selecting spatial types in a *Note `UNION': union. could cause a
     server crash.  (Bug #31155)

   * Use of `GROUP_CONCAT(DISTINCT BIT_COLUMN)' caused an assertion
     failure.  (Bug #31154)

   * The server crashed in the parser when running out of memory.
     Memory handling in the parser has been improved to gracefully
     return an error when out-of-memory conditions occur in the parser.
     (Bug #31153)

   * MySQL declares a `UNIQUE' key as a `PRIMARY' key if it doesn't have
     `NULL' columns and is not a partial key, and the `PRIMARY' key
     must alway be the first key.  However, in some cases, a nonfirst
     key could be reported as `PRIMARY', leading to an assert failure by
     `InnoDB'. This is fixed by correcting the key sort order.  (Bug
     #31137)

   * `GROUP BY NULL WITH ROLLUP' could cause a server crash.  (Bug
     #31095) See also Bug #32558.

   * `REGEXP' operations could cause a server crash for character sets
     such as `ucs2'.  Now the arguments are converted to `utf8' if
     possible, to permit correct results to be produced if the
     resulting strings contain only 8-bit characters.  (Bug #31081)

   * Internal conversion routines could fail for several multi-byte
     character sets (`big5', `cp932', `euckr', `gb2312', `sjis') for
     empty strings or during evaluation of `SOUNDS LIKE'.  (Bug #31069,
     Bug #31070)

   * Many nested subqueries in a single query could led to excessive
     memory consumption and possibly a crash of the server.  (Bug
     #31048)

   * The `MOD()' function and the `%' operator crashed the server for a
     divisor less than 1 with a very long fractional part.  (Bug #31019)

   * On Windows, the `pthread_mutex_trylock()' implementation was
     incorrect.  (Bug #30992)

   * A character set introducer followed by a hexadecimal or bit-value
     literal did not check its argument and could return an ill-formed
     result for invalid input.  (Bug #30986)

   * `CHAR(STR USING CHARSET)' did not check its argument and could
     return an ill-formed result for invalid input.  (Bug #30982)

   * The result from `CHAR(STR USING ucs2') did not add a leading 0x00
     byte for input strings with an odd number of bytes.  (Bug #30981)

   * On Windows, *Note `SHOW PROCESSLIST': show-processlist.  could
     display process entries with a `State' value of `*** DEAD ***'.
     (Bug #30960)

   * The `GeomFromText()' function could cause a server crash if the
     first argument was `NULL' or the empty string.  (Bug #30955)

   * `MAKEDATE()' incorrectly moved year values in the 100 to 200 range
     into the 1970 to 2069 range.  (This is legitimate for 00 to 99,
     but three-digit years should be used unchanged.)  (Bug #30951)

   * When invoked with constant arguments, `STR_TO_DATE()' could use a
     cached value for the format string and return incorrect results.
     (Bug #30942)

   * `GROUP_CONCAT()' returned `','' rather than an empty string when
     the argument column contained only empty strings.  (Bug #30897)

   * `ROUND(X,D)' or `TRUNCATE(X,D)' for nonconstant values of D could
     crash the server if these functions were used in an `ORDER BY'
     that was resolved using `filesort'.  (Bug #30889)

   * For `MEMORY' tables, lookups for `NULL' values in `BTREE' indexes
     could return incorrect results.  (Bug #30885)

   * Calling `NAME_CONST()' with nonconstant arguments triggered an
     assertion failure.  Nonconstant arguments are no longer permitted.
     (Bug #30832)

   * For a spatial column with a regular (non-`SPATIAL') index, queries
     failed if the optimizer tried to use the index.  (Bug #30825)

   * Values for the `--tc-heuristic-recover' option incorrectly were
     treated as values for the `--myisam-stats-method' option.  (Bug
     #30821)

   * The optimizer incorrectly optimized conditions out of the `WHERE'
     clause in some queries involving subqueries and indexed columns.
     (Bug #30788)

   * If an alias was used to refer to the value returned by a stored
     function within a subselect, the outer select recognized the alias
     but failed to retrieve the value assigned to it in the subselect.
     (Bug #30787)

   * Improper calculation of `CASE' expression results could lead to
     value truncation.  (Bug #30782)

   * On Windows, the `pthread_mutex_trylock()' implementation was
     incorrect. One symptom was that invalidating the query cache could
     cause a server crash.  (Bug #30768)

   * A multiple-table *Note `UPDATE': update. involving transactional
     and nontransactional tables caused an assertion failure.  (Bug
     #30763)

   * Under some circumstances, *Note `CREATE TABLE ... SELECT':
     create-table. could crash the server or incorrectly report that
     the table row size was too large.  (Bug #30736)

   * Using the `MIN()' or `MAX()' function to select one part of a
     multi-part key could cause a crash when the function result was
     `NULL'.  (Bug #30715)

   * The optimizer could ignore `ORDER BY' in cases when the result set
     is ordered by `filesort', resulting in rows being returned in
     incorrect order.  (Bug #30666)

   * `MyISAM' tables could not exceed 4294967295 (2^32 - 1) rows on
     Windows.  (Bug #30638)

   * `mysql-test-run.pl' could not run *Note `mysqld': mysqld. with
     `root' privileges.  (Bug #30630)

   * Binary logging for a stored procedure differed depending on
     whether or not execution occurred in a prepared statement.  (Bug
     #30604)

   * For `MEMORY' tables, *Note `DELETE': delete. statements that remove
     rows based on an index read could fail to remove all matching rows.
     (Bug #30590)

   * Using `GROUP BY' on an expression of the form `TIMESTAMP_COL DIV
     NUMBER' caused a server crash due to incorrect calculation of
     number of decimals.  (Bug #30587)

   * The options available to the *Note `CHECK TABLE': check-table.
     statement were also permitted in *Note `OPTIMIZE TABLE':
     optimize-table. and *Note `ANALYZE TABLE': analyze-table.
     statements, but caused corruption during their execution. These
     options were never supported for these statements, and an error is
     now raised if you try to apply these options to these statements.
     (Bug #30495)

   * When expanding a `*' in a `USING' or `NATURAL' join, the check for
     table access for both tables in the join was done using only the
     grant information of the first table.  (Bug #30468)

   * When casting a string value to an integer, cases where the input
     string contained a decimal point and was long enough to overrun
     the `unsigned long long' type were not handled correctly. The
     position of the decimal point was not taken into account which
     resulted in miscalculated numbers and incorrect truncation to
     appropriate SQL data type limits.  (Bug #30453)

   * Versions of *Note `mysqldump': mysqldump. from MySQL 4.1 or higher
     tried to use `START TRANSACTION WITH CONSISTENT SNAPSHOT' if the
     `--single-transaction' and `--master-data' options were given,
     even with servers older than 4.1 that do not support consistent
     snapshots.  (Bug #30444)

   * For `CREATE ... SELECT ... FROM', where the resulting table
     contained indexes, adding `SQL_BUFFER_RESULT' to the *Note
     `SELECT': select. part caused index corruption in the table.  (Bug
     #30384)

   * An orphaned PID file from a no-longer-running process could cause
     *Note `mysql.server': mysql-server. to wait for that process to
     exit even though it does not exist.  (Bug #30378)

   * The optimizer made incorrect assumptions about the value of the
     `is_member' value for user-defined functions, sometimes resulting
     in incorrect ordering of UDF results.  (Bug #30355)

   * Some valid `euc-kr' characters having the second byte in the
     ranges `[0x41..0x5A]' and `[0x61..0x7A]' were rejected.  (Bug
     #30315)

   * Simultaneous *Note `ALTER TABLE': alter-table.  statements for
     `BLACKHOLE' tables caused 100% CPU use due to locking problems.
     (Bug #30294)

   * Setting certain values on a table using a spatial index could
     cause the server to crash.  (Bug #30286)

   * Tables with a `GEOMETRY' column could be marked as corrupt if you
     added a non-`SPATIAL' index on a `GEOMETRY' column.  (Bug #30284)

   * Some `INFORMATION_SCHEMA' tables are intended for internal use,
     but could be accessed by using *Note `SHOW': show. statements.
     (Bug #30079)

   * On some 64-bit systems, inserting the largest negative value into
     a *Note `BIGINT': numeric-types. column resulted in incorrect data.
     (Bug #30069)

   * Specifying the `--without-geometry' option for `configure' caused
     server compilation to fail.  (Bug #29972)

   * Under some circumstances, a UDF initialization function could be
     passed incorrect argument lengths.  (Bug #29804)

   * `configure' did not find `nss' on some Linux platforms.  (Bug
     #29658)

   * The *Note `mysql_config': mysql-config. command would output
     `CFLAGS' values that were incompatible with C++ for the HP-UX
     platform.  (Bug #29645)

   * Views were treated as insertable even if some base table columns
     with no default value were omitted from the view definition.
     (This is contrary to the condition for insertability that a view
     must contain all columns in the base table that do not have a
     default value.)  (Bug #29477)

   * The *Note `mysql': mysql. client program now ignores Unicode byte
     order mark (BOM) characters at the beginning of input files.
     Previously, it read them and sent them to the server, resulting in
     a syntax error.

     Presence of a BOM does not cause *Note `mysql': mysql. to change
     its default character set. To do that, invoke *Note `mysql':
     mysql. with an option such as `--default-character-set=utf8'.
     (Bug #29323)

   * For transactional tables, an error during a multiple-table *Note
     `DELETE': delete. statement did not roll back the statement.  (Bug
     #29136)

   * The `log' and `log_slow_queries' system variables were displayed
     by *Note `SHOW VARIABLES': show-variables. but could not be
     accessed in expressions as `@@log' and `@@log_slow_queries'. Also,
     attempting to set them with *Note `SET': set-option.  produced an
     incorrect `Unknown system variable' message. Now these variables
     can be accessed in expressions and attempting to set their values
     produces an error message that the variable is read only.  (Bug
     #29131)

   * Denormalized double-precision numbers cannot be handled properly
     by old MIPS pocessors. For IRIX, this is now handled by enabling a
     mode to use a software workaround.  (Bug #29085)

   * *Note `SHOW VARIABLES': show-variables. did not display the
     `relay_log', `relay_log_index', or `relay_log_info_file' system
     variables.  (Bug #28893)

   * The MySQL preferences pane did not work to start or stop MySQL on
     Mac OS X 10.5 (Leopard).  (Bug #28854)

   * When doing a *Note `DELETE': delete. on a table that involved a
     `JOIN' with *Note `MyISAM': myisam-storage-engine. or *Note
     `MERGE': merge-storage-engine. tables and the `JOIN' referred to
     the same table, the operation could fail reporting `ERROR 1030
     (HY000): Got error 134 from storage engine'. This was because scans
     on the table contents would change because of rows that had
     already been deleted.  (Bug #28837)

   * On Windows, *Note `mysql_upgrade': mysql-upgrade. created temporary
     files in `C:\' and did not clean them up.  (Bug #28774)

   * Index hints specified in view definitions were ignored when using
     the view to select from the base table.  (Bug #28702)

   * Views do not have indexes, so index hints do not apply. Use of
     index hints when selecting from a view is no longer permitted.
     (Bug #28701)

   * After changing the SQL mode to a restrictive value that would make
     already-inserted dates in a column be considered invalid, searches
     returned different results depending on whether the column was
     indexed.  (Bug #28687)

   * For upgrading to a new major version using RPM packages (such as
     4.1 to 5.0), if the installation procedure found an existing MySQL
     server running, it could fail to shut down the old server, but
     also erroneously removed the server's socket file. Now the
     procedure checks for an existing server package from a different
     vendor or major MySQL version. In such case, it refuses to install
     the server and recommends how to safely remove the old packages
     before installing the new ones.  (Bug #28555)

   * The result from `CHAR()' was incorrectly assumed in some contexts
     to return a single-byte result.  (Bug #28550)

   * *Note `mysqlhotcopy': mysqlhotcopy. silently skipped databases with
     names consisting of two alphanumeric characters.  (Bug #28460)

   * The parser confused user-defined function (UDF) and stored
     function creation for *Note `CREATE FUNCTION': create-function.
     and required that there be a default database when creating UDFs,
     although there is no such requirement.  (Bug #28318, Bug #29816)

   * The SQL parser did not accept an empty `UNION=()' clause. This
     meant that, when there were no underlying tables specified for a
     *Note `MERGE': merge-storage-engine. table, *Note `SHOW CREATE
     TABLE': show-create-table. and *Note `mysqldump': mysqldump. both
     output statements that could not be executed.

     Now it is possible to execute a *Note `CREATE TABLE':
     create-table. or *Note `ALTER TABLE': alter-table.  statement with
     an empty `UNION=()' clause.  However, *Note `SHOW CREATE TABLE':
     show-create-table. and *Note `mysqldump': mysqldump. do not output
     the `UNION=()' clause if there are no underlying tables specified
     for a *Note `MERGE': merge-storage-engine. table.  This also means
     it is now possible to remove the underlying tables for a *Note
     `MERGE': merge-storage-engine. table using *Note `ALTER TABLE ...
     UNION=()': alter-table.  (Bug #28248)

   * The result of a comparison between *Note `VARBINARY':
     binary-varbinary. and *Note `BINARY': binary-varbinary. columns
     differed depending on whether the *Note `VARBINARY':
     binary-varbinary. column was indexed.  (Bug #28076)

   * The metadata in some `MYSQL_FIELD' members could be incorrect when
     a temporary table was used to evaluate a query.  (Bug #27990)

   * An `ORDER BY' at the end of a *Note `UNION': union. affected
     individual *Note `SELECT': select. statements rather than the
     overall query result.  (Bug #27848)

   * *Note `comp_err': comp-err. created files with permissions such
     that they might be inaccessible during `make install' operations.
     (Bug #27789)

   * It was possible to exhaust memory by repeatedly running
     `index_merge' queries and never performing any *Note `FLUSH
     TABLES': flush. statements.  (Bug #27732)

   * The anonymous accounts were not being created during MySQL
     installation.  (Bug #27692)

   * When `utf8' was set as the connection character set, using
     `SPACE()' with a non-Unicode column produced an error.  (Bug
     #27580) See also Bug #23637.

   * A race condition between killing a statement and the thread
     executing the statement could lead to a situation such that the
     binary log contained an event indicating that the statement was
     killed, whereas the statement actually executed to completion.
     (Bug #27571)

   * Some queries using the `NAME_CONST()' function failed to return
     either a result or an error to the client, causing it to hang.
     This was due to the fact that there was no check to insure that
     both arguments to this function were constant expressions.  (Bug
     #27545, Bug #32559)

   * With the `read_only' system variable enabled, *Note `CREATE
     DATABASE': create-database.  and *Note `DROP DATABASE':
     drop-database. were permitted to users who did not have the
     `SUPER' privilege.  (Bug #27440)

   * *Note `resolveip': resolveip. failed to produce correct results
     for host names that begin with a digit.  (Bug #27427)

   * In `ORDER BY' clauses, mixing aggregate functions and nongrouping
     columns is not permitted if the `ONLY_FULL_GROUP_BY' SQL mode is
     enabled. However, in some cases, no error was thrown because of
     insufficient checking.  (Bug #27219)

   * For the `--record_log_pos' option, *Note `mysqlhotcopy':
     mysqlhotcopy. now determines the slave status information from the
     result of *Note `SHOW SLAVE STATUS': show-slave-status. by using
     the `Relay_Master_Log_File' and `Exec_Master_Log_Pos' values
     rather than the `Master_Log_File' and `Read_Master_Log_Pos'
     values. This provides a more accurate indication of slave
     execution relative to the master.  (Bug #27101)

   * The MySQL Instance Configuration Wizard would not permit you to
     choose a service name, even though the criteria for the service
     name were valid. The code that checks the name has been updated to
     support the correct criteria of any string less than 256 character
     and not containing either a forward or backward slash character.
     (Bug #27013)

   * *Note `mysqld': mysqld. sometimes miscalculated the number of
     digits required when storing a floating-point number in a *Note
     `CHAR': char. column. This caused the value to be truncated, or
     (when using a debug build) caused the server to crash.  (Bug
     #26788) See also Bug #12860.

   * `config-win.h' unconditionally defined `bool' as *Note `BOOL':
     numeric-types, causing problems on systems where `bool' is 1 byte
     and *Note `BOOL': numeric-types. is 4 bytes.  (Bug #26461)

   * The internal `init_time()' library function was renamed to
     `my_init_time()' to avoid conflicts with external libraries.  (Bug
     #26294)

   * On Windows, for distributions built with debugging support, *Note
     `mysql': mysql. could crash if the user typed `Control+C'.  (Bug
     #26243)

   * *Note `mysqlcheck -A -r': mysqlcheck. did not correctly identify
     all tables that needed repairing.  (Bug #25347)

   * On Windows, an error in `configure.js' caused installation of
     source distributions to fail.  (Bug #25340)

   * Using *Note `mysqldump': mysqldump. in MySQL 5.1 resulted in dump
     files that could not be loaded in MySQL 5.0 because `USING
     TYPE_NAME' options in index definitions appeared after the index
     column list, whereas 5.0 accepted only the old syntax that has
     `USING' before the column list. The parser in 5.0 now accepts
     `USING' following the column list.  (Bug #25162)

   * The client library had no way to return an error if no connection
     had been established. This caused problems such as *Note
     `mysql_library_init()': mysql-library-init. failing silently if no
     `errmsg.sys' file was available.  (Bug #25097)

   * On Mac OS X, the StartupItem for MySQL did not work.  (Bug #25008)

   * For Windows 64-bit builds, enabling shared-memory support caused
     client connections to fail.  (Bug #24992)

   * If the expected precision of an arithmetic expression exceeded the
     maximum precision supported by MySQL, the precision of the result
     was reduced by an unpredictable or arbitrary amount, rather than
     to the maximum precision. In some cases, exceeding the maximum
     supported precision could also lead to a crash of the server.
     (Bug #24907)

   * *Note `mysql': mysql. did not use its completion table. Also, the
     table contained few entries.  (Bug #24624)

   * If a user installed MySQL Server and set a password for the `root'
     user, and then uninstalled and reinstalled MySQL Server to the
     same location, the user could not use the MySQL Instance Config
     wizard to configure the server because the uninstall operation
     left the previous data directory intact. The config wizard
     _assumed_ that any new install (not an upgrade) would have the
     default data directory where the `root' user has no password. The
     installer now writes a registry key named `FoundExistingDataDir'.
     If the installer finds an existing data directory, the key will
     have a value of 1, otherwise it will have a value of 0. When
     `MySQLInstanceConfig.exe' is run, it will attempt to read the key.
     If it can read the key, and the value is 1 and there is no
     existing instance of the server (indicating a new installation),
     the Config Wizard will permit the user to input the old password
     so the server can be configured.  (Bug #24215)

   * The MySQL header files contained some duplicate macro definitions
     that could cause compilation problems.  (Bug #23839)

   * *Note `SHOW COLUMNS': show-columns. on a `TEMPORARY' table caused
     locking issues.  (Bug #23588)

   * For distributions compiled with the bundled `libedit' library,
     there were difficulties using the *Note `mysql': mysql. client to
     enter input for non-ASCII or multi-byte characters.  (Bug #23097)

   * For Windows Vista, `MySQLInstanceConfig.exe' did not include a
     proper manifest enabling it to run with administrative privileges.
     (Bug #22563) See also Bug #24732.

   * On Mac OS X, *Note `mysqld': mysqld. did not react to Control+C
     when run under `gdb', even when run with the `--gdb' option.  (Bug
     #21567)

   * *Note `mysql_config': mysql-config. output did not include
     `-lmygcc' on some platforms when it was needed.  (Bug #21158)

   * `mysql-stress-test.pl' and `mysqld_multi.server.sh' were missing
     from some binary distributions.  (Bug #21023, Bug #25486)

   * *Note `mysqldumpslow': mysqldumpslow. returned a confusing error
     message when no configuration file was found.  (Bug #20455)

   * Host names sometimes were treated as case sensitive in
     account-management statements (*Note `CREATE USER': create-user,
     *Note `GRANT': grant, *Note `REVOKE': revoke, and so forth).  (Bug
     #19828)

   * The `readline' library has been updated to version 5.2. This
     addresses issues in the *Note `mysql': mysql. client where history
     and editing within the client would fail to work as expected.
     (Bug #18431)

   * The `Aborted_clients' status variable was incremented twice if a
     client exited without calling *Note `mysql_close()': mysql-close.
     (Bug #16918)

   * The parser used signed rather than unsigned values in some cases
     that caused legal lengths in column declarations to be rejected.
     (Bug #15776)

   * A `SET' column whose definition specified 64 elements could not be
     updated using integer values.  (Bug #15409)

   * Clients were ignoring the TCP/IP port number specified as the
     default port using the `--with-tcp-port' configuration option.
     (Bug #15327)

   * Zero-padding of exponent values was not the same across platforms.
     (Bug #12860)

   * Values of types `REAL ZEROFILL', `DOUBLE ZEROFILL', `FLOAT
     ZEROFILL', were not zero-filled when converted to a character
     representation in the C prepared statement API.  (Bug #11589)

   * *Note `mysql': mysql. stripped comments from statements sent to
     the server. Now the `--comments' or `--skip-comments' option can be
     used to control whether to retain or strip comments. The default
     is `--skip-comments'.  (Bug #11230, Bug #26215)

   * If an *Note `INSERT ... SELECT': insert-select. statement is
     executed, and no automatically generated value is successfully
     inserted, then *Note `mysql_insert_id()': mysql-insert-id. returns
     the ID of the last inserted row.

     If no automatically generated value is successfully inserted, then
     *Note `mysql_insert_id()': mysql-insert-id. returns 0.  (Bug #9481)

   * `MySQLInstanceConfig.exe' did not save the `innodb_data_home_dir'
     value to the `my.ini' file under certain circumstances.  (Bug
     #6627)

   * Several buffer-size system variables were either being handled
     incorrectly for large values (for settings larger than 4GB, they
     were truncated to values less than 4GB without a warning), or were
     limited unnecessarily to 4GB even on 64-bit systems. The following
     changes were made:

        * For `key_buffer_size', values larger than 4GB are permitted
          on 64-bit platforms (except Windows, for which large values
          are truncated to 4GB with a warning).

        * For `join_buffer_size', `sort_buffer_size', and
          `myisam_sort_buffer_size', values are limited to 4GB on all
          platforms. Larger values are truncated to 4GB with a warning.

     In addition, settings for `read_buffer_size' and
     `read_rnd_buffer_size' are limited to 2GB on all platforms. Larger
     values are truncated to 2GB with a warning.  (Bug #5731, Bug
     #29419, Bug #29446)

   * Executing `DISABLE KEYS' and `ENABLE KEYS' on a nonempty table
     would cause the size of the index file for the table to grow
     considerable. This was because the `DISABLE KEYS' operation would
     only mark the existing index, without deleting the index blocks.
     The `ENABLE KEYS' operation would re-create the index, adding new
     blocks, while the previous index blocks would remain. Existing
     indexes are now dropped and recreated when the `ENABLE KEYS'
     statement is executed.  (Bug #4692)


File: manual.info,  Node: news-5-0-66sp1,  Next: news-5-0-66a,  Prev: news-5-0-67,  Up: news-5-0-x

D.1.31 Changes in MySQL Enterprise 5.0.66sp1 [QSP] (23 October 2008)
--------------------------------------------------------------------

This is a _Service Pack_ release of the MySQL Enterprise Server 5.0.

This section documents all changes and bugfixes that have been applied
since the last MySQL Enterprise Server release (5.0.66a).

If you would like to receive more fine-grained and personalized _update
alerts_ about fixes that are relevant to the version and features you
use, please consider subscribing to _MySQL Enterprise_ (a commercial
MySQL offering). For more details please see
http://www.mysql.com/products/enterprise/advisors.html.

*Functionality Added or Changed*

   * *Security Enhancement*: To enable stricter control over the
     location from which user-defined functions can be loaded, the
     `plugin_dir' system variable has been backported from MySQL 5.1.
     If the value is nonempty, user-defined function object files can
     be loaded only from the directory named by this variable. If the
     value is empty, the behavior that is used prior to the inclusion of
     `plugin_dir' applies: The UDF object files must be located in a
     directory that is searched by your system's dynamic linker.

     If the plugin directory is writable by the server, it may be
     possible for a user to write executable code to a file in the
     directory using *Note `SELECT ... INTO DUMPFILE': select. This can
     be prevented by making `plugin_dir' read only to the server or by
     setting `--secure-file-priv' to a directory where *Note `SELECT':
     select. writes can be made safely.  (Bug #37428)

*Bugs Fixed*

   * *Important Change*: *Security Fix*: It was possible to circumvent
     privileges through the creation of `MyISAM' tables employing the
     `DATA DIRECTORY' and `INDEX DIRECTORY' options to overwrite
     existing table files in the MySQL data directory. Use of the MySQL
     data directory in `DATA DIRECTORY' and `INDEX DIRECTORY' path name
     is no longer permitted.

     Additional corrections were made to handle the data directory path
     name if it contains symlinked directories in its path, and to make
     the check both at table-creation time and at table-opening time
     later.  (Bug #32167, CVE-2008-2079) See also Bug #39277.

   * *Security Enhancement*: The server consumed excess memory while
     parsing statements with hundreds or thousands of nested boolean
     conditions (such as `OR (OR ... (OR ... ))'). This could lead to a
     server crash or incorrect statement execution, or cause other
     client statements to fail due to lack of memory. The latter result
     constitutes a denial of service.  (Bug #38296)


File: manual.info,  Node: news-5-0-66a,  Next: news-5-0-66,  Prev: news-5-0-66sp1,  Up: news-5-0-x

D.1.32 Changes in MySQL Enterprise 5.0.66a [MRU] (16 July 2008)
---------------------------------------------------------------

This is a _Monthly Rapid Update_ release of the MySQL Enterprise Server
5.0.

This is a bugfix release that replaces MySQL 5.0.66.

*Bugs Fixed*

   * The fix for Bug #20748 caused a problem such that on Unix, MySQL
     programs looked for options in `~/my.cnf' rather than the standard
     location of `~/.my.cnf'.  (Bug #38180)


File: manual.info,  Node: news-5-0-66,  Next: news-5-0-64,  Prev: news-5-0-66a,  Up: news-5-0-x

D.1.33 Changes in MySQL Enterprise 5.0.66 [MRU] (09 July 2008)
--------------------------------------------------------------

This is a _Monthly Rapid Update_ release of the MySQL Enterprise Server
5.0.

*Important*:

This release was withdrawn from production due to the side effect
produced by Bug #20748. It has been replaced by MySQL 5.0.66a, which
should be used instead.

This section documents all changes and bugfixes that have been applied
since the last MySQL Enterprise Server release (5.0.64).  If you would
like to receive more fine-grained and personalized _update alerts_
about fixes that are relevant to the version and features you use,
please consider subscribing to _MySQL Enterprise_ (a commercial MySQL
offering). For more details please see
http://www.mysql.com/products/enterprise/advisors.html.

*Functionality Added or Changed*

   * `mysql-test-run.pl' now supports `--client-bindir' and
     `--client-libdir' options for specifying the directory where
     client binaries and libraries are located.  (Bug #34995)

*Bugs Fixed*

   * *Incompatible Change*: An additional correction to the original
     MySQL 5.0.64 fix was made to normalize directory names before
     adding them to the list of directories. This prevents `/etc/' and
     `/etc' from being considered different, for example.  (Bug #20748)
     See also Bug #38180.

   * *Replication*: Some kinds of internal errors, such as `Out of
     memory' errors, could cause the server to crash when replicating
     statements with user variables.

     certain internal errors.  (Bug #37150)

   * Some binary distributions had a duplicate `-64bit' suffix in the
     file name.  (Bug #37623)

   * The *Note `mysql': mysql. client failed to recognize comment lines
     consisting of `--' followed by a newline.  (Bug #36244)

   * An empty bit-string literal (`b''') caused a server crash. Now the
     value is parsed as an empty bit value (which is treated as an
     empty string in string context or 0 in numeric context).  (Bug
     #35658)

   * *Note `mysqlbinlog': mysqlbinlog. left temporary files on the disk
     after shutdown, leading to the pollution of the temporary
     directory, which eventually caused *Note `mysqlbinlog':
     mysqlbinlog. to fail. This caused problems in testing and other
     situations where *Note `mysqlbinlog': mysqlbinlog. might be
     invoked many times in a relatively short period of time.  (Bug
     #35543)

   * The code for detecting a byte order mark (BOM) caused *Note
     `mysql': mysql. to crash for empty input.  (Bug #35480)

   * The *Note `mysql': mysql. client incorrectly parsed statements
     containing the word `delimiter' in mid-statement.

     The fix for this bug had the side effect of causing the problem
     reported in Bug #38158, so it was reverted in MySQL 5.0.67.  (Bug
     #33812)


File: manual.info,  Node: news-5-0-64,  Next: news-5-0-62,  Prev: news-5-0-66,  Up: news-5-0-x

D.1.34 Changes in MySQL Enterprise 5.0.64 [MRU] (10 June 2008)
--------------------------------------------------------------

This is a _Monthly Rapid Update_ release of the MySQL Enterprise Server
5.0.

This section documents all changes and bugfixes that have been applied
since the last MySQL Enterprise Server release (5.0.62).  If you would
like to receive more fine-grained and personalized _update alerts_
about fixes that are relevant to the version and features you use,
please consider subscribing to _MySQL Enterprise_ (a commercial MySQL
offering). For more details please see
http://www.mysql.com/products/enterprise/advisors.html.

*Functionality Added or Changed*

   * *Important Change*: *Incompatible Change*: The `FEDERATED' storage
     engine is now disabled by default in the `.cnf' files shipped with
     MySQL distributions (`my-huge.cnf', `my-medium.cnf', and so
     forth). This affects server behavior only if you install one of
     these files.  (Bug #37069)

*Bugs Fixed*

   * *Replication*: *Note `CREATE PROCEDURE': create-procedure. and
     *Note `CREATE FUNCTION': create-function. statements containing
     extended comments were not written to the binary log correctly,
     causing parse errors on the slave.  (Bug #36570) See also Bug
     #32575.

   * On Windows 64-bit systems, temporary variables of `long' types
     were used to store `ulong' values, causing key cache
     initialization to receive distorted parameters. The effect was
     that setting `key_buffer_size' to values of 2GB or more caused
     memory exhaustion to due allocation of too much memory.  (Bug
     #36705)

   * Multiple-table *Note `UPDATE': update. statements that used a
     temporary table could fail to update all qualifying rows or fail
     with a spurious duplicate-key error.  (Bug #36676)

   * A `REGEXP' match could return incorrect rows when the previous row
     matched the expression and used `CONCAT()' with an empty string.
     (Bug #36488)

   * For *Note `EXPLAIN EXTENDED': explain, execution of an uncorrelated
     `IN' subquery caused a crash if the subquery required a temporary
     table for its execution.  (Bug #36011)


File: manual.info,  Node: news-5-0-62,  Next: news-5-0-60sp1,  Prev: news-5-0-64,  Up: news-5-0-x

D.1.35 Changes in MySQL Enterprise 5.0.62 [MRU] (12 May 2008)
-------------------------------------------------------------

This is a _Monthly Rapid Update_ release of the MySQL Enterprise Server
5.0.

This section documents all changes and bugfixes that have been applied
since the last MySQL Enterprise Server release (5.0.60).  If you would
like to receive more fine-grained and personalized _update alerts_
about fixes that are relevant to the version and features you use,
please consider subscribing to _MySQL Enterprise_ (a commercial MySQL
offering). For more details please see
http://www.mysql.com/products/enterprise/advisors.html.

*Functionality Added or Changed*

   * *Important Change*: Some changes were made to *Note `CHECK TABLE
     ... FOR UPGRADE': check-table. and *Note `REPAIR TABLE':
     repair-table. with respect to detection and handling of tables
     with incompatible `.frm' files (files created with a different
     version of the MySQL server). These changes also affect *Note
     `mysqlcheck': mysqlcheck. because that program uses *Note `CHECK
     TABLE': check-table. and *Note `REPAIR TABLE': repair-table, and
     thus also *Note `mysql_upgrade': mysql-upgrade. because that
     program invokes *Note `mysqlcheck': mysqlcheck.

        * If your table was created by a different version of the MySQL
          server than the one you are currently running, *Note `CHECK
          TABLE ... FOR UPGRADE': check-table. indicates that the table
          has an `.frm' file with an incompatible version.  In this
          case, the result set returned by *Note `CHECK TABLE':
          check-table. contains a line with a `Msg_type' value of
          `error' and a `Msg_text' value of `Table upgrade required.
          Please do "REPAIR TABLE `TBL_NAME`" to fix it!'

        * *Note `REPAIR TABLE': repair-table. without `USE_FRM'
          upgrades the `.frm' file to the current version.

        * If you use `REPAIR TABLE ...USE_FRM' and your table was
          created by a different version of the MySQL server than the
          one you are currently running, *Note `REPAIR TABLE':
          repair-table. will not attempt to repair the table. In this
          case, the result set returned by *Note `REPAIR TABLE':
          repair-table. contains a line with a `Msg_type' value of
          `error' and a `Msg_text' value of `Failed repairing
          incompatible .FRM file'.

          Previously, use of `REPAIR TABLE ...USE_FRM' with a table
          created by a different version of the MySQL server risked the
          loss of all rows in the table.

     (Bug #36055)

   * *Note `mysql_upgrade': mysql-upgrade. now has a `--tmpdir' option
     to enable the location of temporary files to be specified.  (Bug
     #36469)

*Bugs Fixed*

   * *Important Change*: The server no longer issues warnings for
     truncation of excess spaces for values inserted into *Note `CHAR':
     char. columns. This reverts a change in the previous release that
     caused warnings to be issued.  (Bug #30059)

   * *Replication*: *Note `CREATE VIEW': create-view. statements
     containing extended comments were not written to the binary log
     correctly, causing parse errors on the slave. Now, all comments are
     stripped from such statements before being written to the binary
     log.  (Bug #32575) See also Bug #36570.

   * `mysqltest' ignored the value of `--tmpdir' in one place.  (Bug
     #36465)

   * Conversion of a `FLOAT ZEROFILL' value to string could cause a
     server crash if the value was `NULL'.  (Bug #36139)

   * An error in calculation of the precision of zero-length items
     (such as `NULL') caused a server crash for queries that employed
     temporary tables.  (Bug #36023)

   * The server crashed inside `NOT IN' subqueries with an impossible
     `WHERE' or `HAVING' clause, such as `NOT IN (SELECT ... FROM t1,
     t2, ... WHERE 0)'.  (Bug #36005)

   * Grouping or ordering of long values in unindexed *Note `BLOB':
     blob. or *Note `TEXT': blob. columns with the `gbk' or `big5'
     character set crashed the server.  (Bug #35993)

   * `SET GLOBAL debug=''' resulted in a Valgrind warning in
     `DbugParse()', which was reading beyond the end of the control
     string.  (Bug #35986)

   * The combination of `GROUP_CONCAT()', `DISTINCT', and `LEFT JOIN'
     could crash the server when the right table is empty.  (Bug #35298)

   * Several additional configuration scripts in the `BUILD' directory
     now are included in source distributions. These may be useful for
     users who wish to build MySQL from source. (See *Note
     installing-development-tree::, for information about what they do.)
     (Bug #34291)

   * The internal `init_time()' library function was renamed to
     `my_init_time()' to avoid conflicts with external libraries.  (Bug
     #26294)

   * The parser used signed rather than unsigned values in some cases
     that caused legal lengths in column declarations to be rejected.
     (Bug #15776)


File: manual.info,  Node: news-5-0-60sp1,  Next: news-5-0-60,  Prev: news-5-0-62,  Up: news-5-0-x

D.1.36 Changes in MySQL Enterprise 5.0.60sp1 [QSP] (27 June 2008)
-----------------------------------------------------------------

This is a _Service Pack_ release of the MySQL Enterprise Server 5.0.

This section documents all changes and bugfixes that have been applied
since the last MySQL Enterprise Server release (5.0.60).

If you would like to receive more fine-grained and personalized _update
alerts_ about fixes that are relevant to the version and features you
use, please consider subscribing to _MySQL Enterprise_ (a commercial
MySQL offering). For more details please see
http://www.mysql.com/products/enterprise/advisors.html.

This section has no changelog entries.


File: manual.info,  Node: news-5-0-60,  Next: news-5-0-58,  Prev: news-5-0-60sp1,  Up: news-5-0-x

D.1.37 Changes in MySQL Enterprise 5.0.60 [MRU] (28 April 2008)
---------------------------------------------------------------

This is a _Monthly Rapid Update_ release of the MySQL Enterprise Server
5.0.

This section documents all changes and bugfixes that have been applied
since the last MySQL Enterprise Server release (5.0.58).  If you would
like to receive more fine-grained and personalized _update alerts_
about fixes that are relevant to the version and features you use,
please consider subscribing to _MySQL Enterprise_ (a commercial MySQL
offering). For more details please see
http://www.mysql.com/products/enterprise/advisors.html.

*Functionality Added or Changed*

   * For binary `.tar.gz' packages, *Note `mysqld': mysqld. and other
     binaries now are compiled with debugging symbols included to
     enable easier use with a debugger. If you do not need debugging
     symbols and are short on disk space, you can use `strip' to remove
     the symbols from the binaries.  (Bug #33252)

*Bugs Fixed*

   * *Important Change*: *Security Fix*: It was possible to circumvent
     privileges through the creation of `MyISAM' tables employing the
     `DATA DIRECTORY' and `INDEX DIRECTORY' options to overwrite
     existing table files in the MySQL data directory. Use of the MySQL
     data directory in `DATA DIRECTORY' and `INDEX DIRECTORY' path name
     is no longer permitted.

     *Note*:

     Additional fixes were made in MySQL 5.0.70.

     (Bug #32167, CVE-2008-2079) See also Bug #39277.

   * *Incompatible Change*: It was possible to use `FRAC_SECOND' as a
     synonym for `MICROSECOND' with `DATE_ADD()', `DATE_SUB()', and
     `INTERVAL'; now, using `FRAC_SECOND' with anything other than
     `TIMESTAMPADD()' or `TIMESTAMPDIFF()' produces a syntax error.

     It is now possible (and preferable) to use `MICROSECOND' with
     `TIMESTAMPADD()' and `TIMESTAMPDIFF()', and `FRAC_SECOND' is now
     deprecated.  (Bug #33834)

   * *Important Change*: The server handled truncation of values having
     excess trailing spaces into *Note `CHAR': char, *Note `VARCHAR':
     char, and *Note `TEXT': blob. columns in different ways.  This
     behavior has now been made consistent for columns of all three of
     these types, and now follows the existing behavior of *Note
     `VARCHAR': char. columns in this regard; that is, a `Note' is
     always issued whenever such truncation occurs.

     This change does not affect columns of these three types when
     using a binary encoding; *Note `BLOB': blob.  columns are also
     unaffected by the change, since they always use a binary encoding.
     (Bug #30059)

   * *Replication*: `insert_id' was not written to the binary log for
     inserts into `BLACKHOLE' tables.  (Bug #35178)

   * *Replication*: The character sets and collations used for constant
     identifiers in stored procedures were not replicated correctly.
     (Bug #34289)

   * *Replication*: An extraneous *Note `ROLLBACK': commit.  statement
     was written to the binary log by a connection that did not use any
     transactional tables.  (Bug #33329)

   * *Replication*: When a stored routine or trigger, running on a
     master that used MySQL 5.0 or MySQL 5.1.11 or earlier, performed
     an insert on an `AUTO_INCREMENT' column, the `insert_id' value was
     not replicated correctly to a slave running MySQL 5.1.12 or later
     (including any MySQL 6.0 release).  (Bug #33029) See also Bug
     #19630.

   * *Replication*: *Note `STOP SLAVE': stop-slave. did not stop
     connection attempts properly. If the I/O slave thread was
     attempting to connect, *Note `STOP SLAVE': stop-slave.  waited for
     the attempt to finish, sometimes for a long period of time, rather
     than stopping the slave immediately.  (Bug #31024) See also Bug
     #30932.

   * *Replication*: `MASTER_POS_WAIT()' did not return `NULL' when the
     server was not a slave.  (Bug #26622)

   * *Replication*: The nonspecific error message `Wrong parameters to
     function register_slave' resulted when *Note `START SLAVE':
     start-slave. failed to register on the master due to excess length
     of any the slave server options `--report-host', `--report-user',
     or `--report-password'. An error message specific to each of these
     options is now returned in such cases. The new error messages are:

        * `Failed to register slave: too long 'report-host''

        * `Failed to register slave: too long 'report-user''

        * `Failed to register slave; too long 'report-password''

     (Bug #22989) See also Bug #19328.

   * *Replication*: `PURGE BINARY LOGS TO' and `PURGE BINARY LOGS
     BEFORE' did not handle missing binary log files correctly or in
     the same way. Now for both of these statements, if any files
     listed in the `.index' file are missing from the file system, the
     statement fails with an error.  (Bug #18199, Bug #18453)

   * *Replication*: `START SLAVE UNTIL MASTER_LOG_POS=POSITION' issued
     on a slave that was using `--log-slave-updates' and that was
     involved in circular replication would cause the slave to run and
     stop one event later than that specified by the value of POSITION.
     (Bug #13861)

   * On Windows, the installer attempted to use JScript to determine
     whether the target data directory already existed. On Windows
     Vista x64, this resulted in an error because the installer was
     attempting to run the JScript in a 32-bit engine, which wasn't
     registered on Vista. The installer no longer uses JScript but
     instead relies on a native WiX command.  (Bug #36103)

   * There was a memory leak when connecting to a `FEDERATED' table
     using a connection string that had a host value of `localhost' or
     omitted the host and a port value of `0' or omitted the port.
     (Bug #35509)

   * Using *Note `LOAD DATA INFILE': load-data. with a view could crash
     the server.  (Bug #35469)

   * When a view containing a reference to `DUAL' was created, the
     reference was removed when the definition was stored, causing some
     queries against the view to fail with invalid SQL syntax errors.
     (Bug #35193)

   * Debugging symbols were missing for some executables in Windows
     binary distributions.  (Bug #35104)

   * A query that performed a `ref_or_null' join where the second table
     used a key having one or columns that could be `NULL' and had a
     column value that was `NULL' caused the server to crash.  (Bug
     #34945) This regression was introduced by Bug #12144.

   * Some binaries produced stack corruption messages due to being
     built with versions of `bison' older than 2.1.  Builds are now
     created using `bison' 2.3.  (Bug #34926)

   * *Note `mysqldump': mysqldump. failed to return an error code when
     using the `--master-data' option without binary logging being
     enabled on the server.  (Bug #34909)

   * Under some circumstances, the value of *Note `mysql_insert_id()':
     mysql-insert-id. following a `SELECT ... INSERT' statement could
     return an incorrect value. This could happen when the last `SELECT
     ... INSERT' did not involve an `AUTO_INCREMENT' column, but the
     value of *Note `mysql_insert_id()': mysql-insert-id. was changed by
     some previous statements.  (Bug #34889)

   * Table and database names were mixed up in some places of the
     subquery transformation procedure. This could affect debugging
     trace output and further extensions of that procedure.  (Bug
     #34830)

   * A malformed URL used for a `FEDERATED' table's `CONNECTION' option
     value in a *Note `CREATE TABLE': create-table. statement was not
     handled correctly and could crash the server.  (Bug #34788)

   * Queries such as `SELECT ROW(1, 2) IN (SELECT t1.a, 2) FROM t1
     GROUP BY t1.a' (combining row constructors and subqueries in the
     `FROM' clause) could lead to assertion failure or unexpected error
     messages.  (Bug #34763)

   * Using `NAME_CONST()' with a negative number and an aggregate
     function caused MySQL to crash. This could also have a negative
     impact on replication.  (Bug #34749)

   * A memory-handling error associated with use of `GROUP_CONCAT()' in
     subqueries could result in a server crash.  (Bug #34747)

   * For an indexed integer column COL_NAME and a value N that is one
     greater than the maximum value permitted for the data type of
     COL_NAME, conditions of the form `WHERE COL_NAME < N' failed to
     return rows where the value of COL_NAME is `N - 1'.  (Bug #34731)

   * Executing a *Note `TRUNCATE TABLE': truncate-table.  statement on
     a table having both a foreign key reference and a `DELETE' trigger
     crashed the server.  (Bug #34643)

   * Some subqueries using an expression that included an aggregate
     function could fail or in some cases lead to a crash of the server.
     (Bug #34620)

   * A server crash could occur if `INFORMATION_SCHEMA' tables built in
     memory were swapped out to disk during query execution.  (Bug
     #34529)

   * `CAST(AVG(ARG) AS DECIMAL)' produced incorrect results for
     non-*Note `DECIMAL': numeric-types. arguments.  (Bug #34512)

   * Under some conditions, a `SET GLOBAL innodb_commit_concurrency' or
     `SET GLOBAL innodb_autoextend_increment' statement could fail.
     (Bug #34223)

   * *Note `mysqldump': mysqldump. attempts to set the
     `character_set_results' system variable after connecting to the
     server. This failed for pre-4.1 servers that have no such
     variable, but *Note `mysqldump': mysqldump. did not account for
     this and 1) failed to dump database contents; 2) failed to produce
     any error message alerting the user to the problem.  (Bug #34192)

   * For a `FEDERATED' table with an index on a nullable column,
     accessing the table could crash a server, return an incorrect
     result set, or return `ERROR 1030 (HY000): Got error 1430 from
     storage engine'.  (Bug #33946)

   * A query using `WHERE (column1='STRING1' AND column2=CONSTANT1) OR
     (column1='STRING2' AND column2=CONSTANT2)', where `col1' used a
     binary collation and STRING1 matched STRING2 except for case,
     failed to match any records even when matches were found by a
     query using the equivalent clause `WHERE column2=CONSTANT1 OR
     column2=CONSTANT2'.  (Bug #33833)

   * Reuse of prepared statements could cause a memory leak in the
     embedded server.  (Bug #33796)

   * Some queries using a combination of `IN', `CONCAT()', and an
     implicit type conversion could return an incorrect result.  (Bug
     #33764)

   * In some cases a query that produced a result set when using `ORDER
     BY ASC' did not return any results when this was changed to `ORDER
     BY DESC'.  (Bug #33758)

   * Disabling concurrent inserts caused some cacheable queries not to
     be saved in the query cache.  (Bug #33756)

   * Certain combinations of views, subselects with outer references
     and stored routines or triggers could cause the server to crash.
     (Bug #33389)

   * `SLEEP(0)' failed to return on 64-bit Mac OS X due to a bug in
     `pthread_cond_timedwait()'.  (Bug #33304)

   * Granting the `UPDATE' privilege on one column of a view caused the
     server to crash.  (Bug #33201)

   * Under some circumstances a combination of aggregate functions and
     `GROUP BY' in a *Note `SELECT': select. query over a view could
     lead to incorrect calculation of the result type of the aggregate
     function. This in turn could lead to incorrect results, or to
     crashes on debug builds of the server.  (Bug #33049)

   * For `DISTINCT' queries, MySQL 4.0 and 4.1 stopped reading joined
     tables as soon as the first matching row was found. However, this
     optimization was lost in MySQL 5.0, which instead read all
     matching rows. This fix for this regression may result in a major
     improvement in performance for `DISTINCT' queries in cases where
     many rows match.  (Bug #32942)

   * Incorrect assertions could cause a server crash for `DELETE'
     triggers for transactional tables.  (Bug #32790)

   * Inserting strings with a common prefix into a table that used the
     `ucs2' character set corrupted the table.  (Bug #32705)

   * Queries using `LIKE' on tables having indexed *Note `CHAR': char.
     columns using either of the `eucjpms' or `ujis' character sets did
     not return correct results.  (Bug #32510)

   * Queries testing numeric constants containing leading zeros against
     `ZEROFILL' columns were not evaluated correctly.  (Bug #31887)

   * If an error occurred during file creation, the server sometimes
     did not remove the file, resulting in an unused file in the file
     system.  (Bug #31781)

   * The server returned the error message `Out of memory; restart
     server and try again' when the actual problem was that the sort
     buffer was too small. Now an appropriate error message is returned
     in such cases.  (Bug #31590)

   * When sorting privilege table rows, the server treated escaped
     wildcard characters (`\%' and `\_') the same as unescaped wildcard
     characters (`%' and `_'), resulting in incorrect row ordering.
     (Bug #31194)

   * On Windows, *Note `SHOW PROCESSLIST': show-processlist.  could
     display process entries with a `State' value of `*** DEAD ***'.
     (Bug #30960)

   * If an alias was used to refer to the value returned by a stored
     function within a subselect, the outer select recognized the alias
     but failed to retrieve the value assigned to it in the subselect.
     (Bug #30787)

   * Binary logging for a stored procedure differed depending on
     whether or not execution occurred in a prepared statement.  (Bug
     #30604)

   * An orphaned PID file from a no-longer-running process could cause
     *Note `mysql.server': mysql-server. to wait for that process to
     exit even though it does not exist.  (Bug #30378)

   * The *Note `mysql_config': mysql-config. command would output
     `CFLAGS' values that were incompatible with C++ for the HP-UX
     platform.  (Bug #29645)

   * The SQL parser did not accept an empty `UNION=()' clause. This
     meant that, when there were no underlying tables specified for a
     *Note `MERGE': merge-storage-engine. table, *Note `SHOW CREATE
     TABLE': show-create-table. and *Note `mysqldump': mysqldump. both
     output statements that could not be executed.

     Now it is possible to execute a *Note `CREATE TABLE':
     create-table. or *Note `ALTER TABLE': alter-table.  statement with
     an empty `UNION=()' clause.  However, *Note `SHOW CREATE TABLE':
     show-create-table. and *Note `mysqldump': mysqldump. do not output
     the `UNION=()' clause if there are no underlying tables specified
     for a *Note `MERGE': merge-storage-engine. table.  This also means
     it is now possible to remove the underlying tables for a *Note
     `MERGE': merge-storage-engine. table using *Note `ALTER TABLE ...
     UNION=()': alter-table.  (Bug #28248)

   * It was possible to exhaust memory by repeatedly running
     `index_merge' queries and never performing any *Note `FLUSH
     TABLES': flush. statements.  (Bug #27732)

   * When `utf8' was set as the connection character set, using
     `SPACE()' with a non-Unicode column produced an error.  (Bug
     #27580) See also Bug #23637.

   * In `ORDER BY' clauses, mixing aggregate functions and nongrouping
     columns is not permitted if the `ONLY_FULL_GROUP_BY' SQL mode is
     enabled. However, in some cases, no error was thrown because of
     insufficient checking.  (Bug #27219)

   * For the `--record_log_pos' option, *Note `mysqlhotcopy':
     mysqlhotcopy. now determines the slave status information from the
     result of *Note `SHOW SLAVE STATUS': show-slave-status. by using
     the `Relay_Master_Log_File' and `Exec_Master_Log_Pos' values
     rather than the `Master_Log_File' and `Read_Master_Log_Pos'
     values. This provides a more accurate indication of slave
     execution relative to the master.  (Bug #27101)

   * The MySQL Instance Configuration Wizard would not permit you to
     choose a service name, even though the criteria for the service
     name were valid. The code that checks the name has been updated to
     support the correct criteria of any string less than 256 character
     and not containing either a forward or backward slash character.
     (Bug #27013)

   * `config-win.h' unconditionally defined `bool' as *Note `BOOL':
     numeric-types, causing problems on systems where `bool' is 1 byte
     and *Note `BOOL': numeric-types. is 4 bytes.  (Bug #26461)

   * On Windows, for distributions built with debugging support, *Note
     `mysql': mysql. could crash if the user typed `Control+C'.  (Bug
     #26243)

   * On Windows, an error in `configure.js' caused installation of
     source distributions to fail.  (Bug #25340)

   * Using *Note `mysqldump': mysqldump. in MySQL 5.1 resulted in dump
     files that could not be loaded in MySQL 5.0 because `USING
     TYPE_NAME' options in index definitions appeared after the index
     column list, whereas 5.0 accepted only the old syntax that has
     `USING' before the column list. The parser in 5.0 now accepts
     `USING' following the column list.  (Bug #25162)

   * The client library had no way to return an error if no connection
     had been established. This caused problems such as *Note
     `mysql_library_init()': mysql-library-init. failing silently if no
     `errmsg.sys' file was available.  (Bug #25097)

   * On Mac OS X, the StartupItem for MySQL did not work.  (Bug #25008)

   * For Windows 64-bit builds, enabling shared-memory support caused
     client connections to fail.  (Bug #24992)

   * If a user installed MySQL Server and set a password for the `root'
     user, and then uninstalled and reinstalled MySQL Server to the
     same location, the user could not use the MySQL Instance Config
     wizard to configure the server because the uninstall operation
     left the previous data directory intact. The config wizard
     _assumed_ that any new install (not an upgrade) would have the
     default data directory where the `root' user has no password. The
     installer now writes a registry key named `FoundExistingDataDir'.
     If the installer finds an existing data directory, the key will
     have a value of 1, otherwise it will have a value of 0. When
     `MySQLInstanceConfig.exe' is run, it will attempt to read the key.
     If it can read the key, and the value is 1 and there is no
     existing instance of the server (indicating a new installation),
     the Config Wizard will permit the user to input the old password
     so the server can be configured.  (Bug #24215)

   * The MySQL header files contained some duplicate macro definitions
     that could cause compilation problems.  (Bug #23839)

   * *Note `SHOW COLUMNS': show-columns. on a `TEMPORARY' table caused
     locking issues.  (Bug #23588)

   * For distributions compiled with the bundled `libedit' library,
     there were difficulties using the *Note `mysql': mysql. client to
     enter input for non-ASCII or multi-byte characters.  (Bug #23097)

   * On Mac OS X, *Note `mysqld': mysqld. did not react to Control+C
     when run under `gdb', even when run with the `--gdb' option.  (Bug
     #21567)

   * `mysql-stress-test.pl' and `mysqld_multi.server.sh' were missing
     from some binary distributions.  (Bug #21023, Bug #25486)

   * A `SET' column whose definition specified 64 elements could not be
     updated using integer values.  (Bug #15409)

   * `MySQLInstanceConfig.exe' did not save the `innodb_data_home_dir'
     value to the `my.ini' file under certain circumstances.  (Bug
     #6627)


File: manual.info,  Node: news-5-0-58,  Next: news-5-0-56sp1,  Prev: news-5-0-60,  Up: news-5-0-x

D.1.38 Changes in MySQL Enterprise 5.0.58 [MRU] (05 March 2008)
---------------------------------------------------------------

This is a _Monthly Rapid Update_ release of the MySQL Enterprise Server
5.0.

This section documents all changes and bugfixes that have been applied
since the last MySQL Enterprise Server release (5.0.56).  If you would
like to receive more fine-grained and personalized _update alerts_
about fixes that are relevant to the version and features you use,
please consider subscribing to _MySQL Enterprise_ (a commercial MySQL
offering). For more details please see
http://www.mysql.com/products/enterprise/advisors.html.

*Functionality Added or Changed*

   * *Cluster API*: *Important Change*: Because
     `NDB_LE_MemoryUsage.page_size_kb' shows memory page sizes in bytes
     rather than kilobytes, it has been renamed to `page_size_bytes'.
     The name `page_size_kb' is now deprecated and thus subject to
     removal in a future release, although it currently remains
     supported for reasons of backward compatibility. See The
     `Ndb_logevent_type' Type
     (http://dev.mysql.com/doc/ndbapi/en/mgm-ndb-logevent-type.html),
     for more information about `NDB_LE_MemoryUsage'.  (Bug #30271)

   * The *Note `ndbd': mysql-cluster-programs-ndbd. and *Note
     `ndb_mgmd': mysql-cluster-programs-ndb-mgmd. man pages have been
     reclassified from volume 1 to volume 8.  (Bug #34642)

   * `mysqltest' now has `mkdir' and `rmdir' commands for creating and
     removing directories.  (Bug #31004)

*Bugs Fixed*

   * *Performance*: `InnoDB' adaptive hash latches could be held too
     long during filesort operations, resulting in a server crash. Now
     the hash latch is released when a query on `InnoDB' tables
     performs a filesort. This eliminates the crash and may provide
     significant performance improvements on systems on which many
     queries using filesorts with temporary tables are being performed.
     (Bug #32149)

   * *MySQL Cluster*: When configured with *Note `NDB': mysql-cluster.
     support, MySQL failed to compile using `gcc' 4.3 on 64bit FreeBSD
     systems.  (Bug #34169)

   * *MySQL Cluster*: The failure of a DDL statement could sometimes
     lead to node failures when attempting to execute subsequent DDL
     statements.  (Bug #34160)

   * *MySQL Cluster*: Extremely long *Note `SELECT': select. statements
     (where the text of the statement was in excess of 50000
     characters) against *Note `NDB': mysql-cluster. tables returned
     empty results.  (Bug #34107)

   * *MySQL Cluster*: A periodic failure to flush the send buffer by the
     *Note `NDB': mysql-cluster. TCP transporter could cause a
     unnecessary delay of 10 ms between operations.  (Bug #34005)

   * *MySQL Cluster*: When all data and SQL nodes in the cluster were
     shut down abnormally (that is, other than by using `STOP' in the
     cluster management client), *Note `ndb_mgm':
     mysql-cluster-programs-ndb-mgm.  used excessive amounts of CPU.
     (Bug #33237)

   * *MySQL Cluster*: Transaction atomicity was sometimes not preserved
     between reads and inserts under high loads.  (Bug #31477)

   * *MySQL Cluster*: Numerous *Note `NDBCLUSTER': mysql-cluster. test
     failures occurred in builds compiled using `icc' on IA64 platforms.
     (Bug #31239)

   * *MySQL Cluster*: Having tables with a great many columns could
     cause Cluster backups to fail.  (Bug #30172)

   * *MySQL Cluster*: Issuing an *Note `INSERT ... ON DUPLICATE KEY
     UPDATE': insert-on-duplicate. concurrently with or following a
     *Note `TRUNCATE TABLE': truncate-table. statement on an *Note
     `NDB': mysql-cluster. table failed with *Note `NDB':
     mysql-cluster. error 4350 `Transaction already aborted'.  (Bug
     #29851)

   * *MySQL Cluster*: It was possible in `config.ini' to define cluster
     nodes having node IDs greater than the maximum permitted value.
     (Bug #28298)

   * *Cluster API*: When reading a `BIT(64)' value using
     `NdbOperation:getValue()', 12 bytes were written to the buffer
     rather than the expected 8 bytes.  (Bug #33750)

   * *Note `mysql_explain_log': mysql-explain-log. concatenated
     multiple-line statements, causing malformed results for statements
     that contained SQL comments beginning with `--'.  (Bug #34339)

   * Executing an *Note `ALTER VIEW': alter-view. statement on a table
     crashed the server.  (Bug #34337)

   * Passing anything other than an integer argument to a `LIMIT'
     clause in a prepared statement would fail. (This limitation was
     introduced to avoid replication problems; for example, replicating
     the statement with a string argument would cause a parse failure
     in the slave). Now, arguments to the `LIMIT' clause are converted
     to integer values, and these converted values are used when
     logging the statement.  (Bug #33851)

   * An internal buffer in *Note `mysql': mysql. was too short.
     Overextending it could cause stack problems or segmentation
     violations on some architectures. (This is not a problem that
     could be exploited to run arbitrary code.)  (Bug #33841)

   * Large unsigned integers were improperly handled for prepared
     statements, resulting in truncation or conversion to negative
     numbers.  (Bug #33798)

   * `make_binary_distribution' passed the `--print-libgcc-file' option
     to the C compiler, but this does not work with the `ICC' compiler.
     (Bug #33536)

   * When MySQL was built with OpenSSL, the SSL library was not
     properly initialized with information of which endpoint it was
     (server or client), causing connection failures.  (Bug #33050)

   * Repeated creation and deletion of views within prepared statements
     could eventually crash the server.  (Bug #32890) See also Bug
     #34587.

   * Executing a prepared statement associated with a materialized
     cursor sent to the client a metadata packet with incorrect table
     and database names. The problem occurred because the server sent
     the name of the temporary table used by the cursor instead of the
     table name of the original table.

     The same problem occurred when selecting from a view, in which
     case the name of the table name was sent, rather than the name of
     the view.  (Bug #32265)

   * *Note `SHOW STATUS': show-status. caused a server crash if
     `InnoDB' had not been initialized.  (Bug #32083)

   * The *Note `mysqld': mysqld. crash handler failed on Windows.  (Bug
     #31745)

   * The MySQL preferences pane did not work to start or stop MySQL on
     Mac OS X 10.5 (Leopard).  (Bug #28854)

   * For upgrading to a new major version using RPM packages (such as
     4.1 to 5.0), if the installation procedure found an existing MySQL
     server running, it could fail to shut down the old server, but
     also erroneously removed the server's socket file. Now the
     procedure checks for an existing server package from a different
     vendor or major MySQL version. In such case, it refuses to install
     the server and recommends how to safely remove the old packages
     before installing the new ones.  (Bug #28555)

   * *Note `mysqlhotcopy': mysqlhotcopy. silently skipped databases with
     names consisting of two alphanumeric characters.  (Bug #28460)

   * *Note `mysql': mysql. did not use its completion table. Also, the
     table contained few entries.  (Bug #24624)

   * *Note `mysql_config': mysql-config. output did not include
     `-lmygcc' on some platforms when it was needed.  (Bug #21158)


File: manual.info,  Node: news-5-0-56sp1,  Next: news-5-0-56,  Prev: news-5-0-58,  Up: news-5-0-x

D.1.39 Changes in MySQL Enterprise 5.0.56sp1 [QSP] (30 March 2008)
------------------------------------------------------------------

This is a _Service Pack_ release of the MySQL Enterprise Server 5.0.

This section documents all changes and bugfixes that have been applied
in MySQL 5.0.56sp1 since the previous MySQL Enterprise Server Quarterly
Service Pack release (5.0.50sp1a). If you would like to receive more
fine-grained and personalized _update alerts_ about fixes that are
relevant to the version and features you use, please consider
subscribing to _MySQL Enterprise_ (a commercial MySQL offering). For
more details please see
http://www.mysql.com/products/enterprise/advisors.html.

*Functionality Added or Changed*

   * *Note `mysqldump': mysqldump. produces a `-- Dump completed on
     DATE' comment at the end of the dump if `--comments' is given. The
     date causes dump files for identical data take at different times
     to appear to be different. The new options `--dump-date' and
     `--skip-dump-date' control whether the date is added to the
     comment.  `--skip-dump-date' suppresses date printing. The default
     is `--dump-date' (include the date in the comment).  (Bug #31077)

   * The `mysql_odbc_escape_string()' C API function has been removed.
     It has multi-byte character escaping issues, doesn't honor the
     `NO_BACKSLASH_ESCAPES' SQL mode and is not needed anymore by
     Connector/ODBC as of 3.51.17.  (Bug #29592) See also Bug #41728.

   * The default value of the `connect_timeout' system variable was
     increased from 5 to 10 seconds. This might help in cases where
     clients frequently encounter errors of the form `Lost connection
     to MySQL server at 'XXX', system error: ERRNO'.  (Bug #28359)

   * The use of `InnoDB' hash indexes now can be controlled by setting
     the new `innodb_adaptive_hash_index' system variable at server
     startup. By default, this variable is enabled. See *Note
     innodb-adaptive-hash::.

   * The argument for the `mysql-test-run.pl' `--do-test' and
     `--skip-test' options is now interpreted as a Perl regular
     expression if there is a pattern metacharacter in the argument
     value. This enables more flexible specification of which tests to
     perform or skip.

*Bugs Fixed*

   * *Performance*: `InnoDB' had a race condition for an adaptive hash
     rw-lock waiting for an X-lock. This fix may also provide
     significant speed improvements on systems experiencing problems
     with contention for the adaptive hash index.  (Bug #29560)

   * *Security Fix*: Using *Note `RENAME TABLE': rename-table. against a
     table with explicit `DATA DIRECTORY' and `INDEX DIRECTORY' options
     can be used to overwrite system table information by replacing the
     symbolic link points. the file to which the symlink points.

     MySQL will now return an error when the file to which the symlink
     points already exists.  (Bug #32111, CVE-2007-5969)

   * *Security Fix*: *Note `ALTER VIEW': alter-view. retained the
     original `DEFINER' value, even when altered by another user, which
     could enable that user to gain the access rights of the view. Now
     *Note `ALTER VIEW': alter-view. is permitted only to the original
     definer or users with the `SUPER' privilege.  (Bug #29908)

   * *Security Fix*: When using a `FEDERATED' table, the local server
     could be forced to crash if the remote server returned a result
     with fewer columns than expected.  (Bug #29801)

   * *Security Enhancement*: It was possible to force an error message
     of excessive length which could lead to a buffer overflow. This
     has been made no longer possible as a security precaution.  (Bug
     #32707)

   * *Incompatible Change*: With `ONLY_FULL_GROUP_BY' SQL mode enabled,
     queries such as `SELECT a FROM t1 HAVING COUNT(*)>2' were not
     being rejected as they should have been.

     This fix results in the following behavior:

        * There is a check against mixing group and nongroup columns
          _only_ when `ONLY_FULL_GROUP_BY' is enabled.

        * This check is done both for the select list and for the
          `HAVING' clause if there is one.

     This behavior differs from previous versions as follows:

        * Previously, the `HAVING' clause was not checked when
          `ONLY_FULL_GROUP_BY' was enabled; now it is checked.

        * Previously, the select list was checked even when
          `ONLY_FULL_GROUP_BY' was not enabled; now it is checked only
          when `ONLY_FULL_GROUP_BY' is enabled.

     (Bug #31794)

   * *Incompatible Change*: The MySQL 5.0.50 patch for this bug was
     reverted because it changed the behavior of a General Availability
     MySQL release.  (Bug #30234) See also Bug #27525.

   * *Incompatible Change*: It was possible to create a view having a
     column whose name consisted of an empty string or space characters
     only.

     One result of this bug fix is that aliases for columns in the view
     `SELECT' statement are checked to ensure that they are legal
     column names. In particular, the length must be within the maximum
     column length of 64 characters, not the maximum alias length of
     256 characters. This can cause problems for replication or loading
     dump files. For additional information and workarounds, see *Note
     view-restrictions::.  (Bug #27695) See also Bug #31202.

   * *Incompatible Change*: Several type-preserving functions and
     operators returned an incorrect result type that does not match
     their argument types: `COALESCE()', `IF()', `IFNULL()', `LEAST()',
     `GREATEST()', `CASE'. These now aggregate using the precise SQL
     types of their arguments rather than the internal type. In
     addition, the result type of the `STR_TO_DATE()' function is now
     *Note `DATETIME': datetime. by default.  (Bug #27216)

   * *Incompatible Change*: It was possible for option files to be read
     twice at program startup, if some of the standard option file
     locations turned out to be the same directory. Now duplicates are
     removed from the list of files to be read.

     Also, users could not override system-wide settings using
     `~/.my.cnf' because `SYSCONFDIR/my.cnf' was read last. The latter
     file now is read earlier so that `~/.my.cnf' can override
     system-wide settings.

     The fix for this problem had a side effect such that on Unix,
     MySQL programs looked for options in `~/my.cnf' rather than the
     standard location of `~/.my.cnf'. That problem was addressed as
     Bug #38180.  (Bug #20748)

   * *Important Change*: *MySQL Cluster*: `AUTO_INCREMENT' columns had
     the following problems when used in *Note `NDB': mysql-cluster.
     tables:

        * The `AUTO_INCREMENT' counter was not updated correctly when
          such a column was updated.

        * `AUTO_INCREMENT' values were not prefetched beyond statement
          boundaries.

        * `AUTO_INCREMENT' values were not handled correctly with *Note
          `INSERT IGNORE': insert. statements.

        * After being set, `ndb_autoincrement_prefetch_sz' showed a
          value of 1, regardless of the value it had actually been set
          to.

     As part of this fix, the behavior of
     `ndb_autoincrement_prefetch_sz' has changed. Setting this to less
     than 32 no longer has any effect on prefetching within statements
     (where IDs are now always obtained in batches of 32 or more), but
     only between statements. The default value for this variable has
     also changed, and is now `1'.  (Bug #25176, Bug #31956, Bug #32055)

   * *Important Change*: *Replication*: When the master crashed during
     an update on a transactional table while in `autocommit' mode, the
     slave failed. This fix causes every transaction (including
     `autocommit' transactions) to be recorded in the binary log as
     starting with a *Note `BEGIN': commit. and ending with a *Note
     `COMMIT': commit. or *Note `ROLLBACK': commit.

     *Note*:

     The current fix does _not_ cause nontransactional changes to be
     wrapped in *Note `BEGIN': commit ...  *Note `COMMIT': commit. or
     *Note `BEGIN': commit ...  *Note `ROLLBACK': commit.  when written
     to the binary log. For this purpose, any statements affecting
     tables using a nontransactional storage engine such as *Note
     `MyISAM': myisam-storage-engine. are regarded as nontransactional,
     even when `autocommit' is enabled.

     (Bug #26395) See also Bug #29288, Bug #49522.

   * *Replication*: *Important Note*: Network timeouts between the
     master and the slave could result in corruption of the relay log.
     This fix rectifies a long-standing replication issue when using
     unreliable networks, including replication over wide area networks
     such as the Internet. If you experience reliability issues and see
     many `You have an error in your SQL syntax' errors on replication
     slaves, we strongly recommend that you upgrade to a MySQL version
     which includes this fix.  (Bug #26489)

   * *MySQL Cluster*: An improperly reset internal signal was observed
     as a hang when using events in the *Note `NDB': mysql-cluster. API
     but could result in various errors.  (Bug #33206)

   * *MySQL Cluster*: Incorrectly handled parameters could lead to a
     crash in the Transaction Coordinator during a node failure,
     causing other data nodes to fail.  (Bug #33168)

   * *MySQL Cluster*: The failure of a master node could lead to
     subsequent failures in local checkpointing.  (Bug #32160)

   * *MySQL Cluster*: An uninitialized variable in the *Note `NDB':
     mysql-cluster. storage engine code led to `AUTO_INCREMENT'
     failures when the server was compiled with `gcc' 4.2.1.  (Bug
     #31848) This regression was introduced by Bug #27437.

   * *MySQL Cluster*: An error with an `if' statement in
     `sql/ha_ndbcluster.cc' could potentially lead to an infinite loop
     in case of failure when working with `AUTO_INCREMENT' columns in
     *Note `NDB': mysql-cluster. tables.  (Bug #31810)

   * *MySQL Cluster*: The *Note `NDB': mysql-cluster. storage engine
     code was not safe for strict-alias optimization in `gcc' 4.2.1.
     (Bug #31761)

   * *MySQL Cluster*: Primary keys on variable-length columns (such as
     *Note `VARCHAR': char.) did not work correctly.  (Bug #31635)

   * *MySQL Cluster*: Transaction timeouts were not handled well in some
     circumstances, leading to excessive number of transactions being
     aborted unnecessarily.  (Bug #30379)

   * *MySQL Cluster*: In some cases, the cluster managment server
     logged entries multiple times following a restart of *Note
     `ndb_mgmd': mysql-cluster-programs-ndb-mgmd.  (Bug #29565)

   * *MySQL Cluster*: An interpreted program of sufficient size and
     complexity could cause all cluster data nodes to shut down due to
     buffer overruns.  (Bug #29390)

   * *MySQL Cluster*: `UPDATE IGNORE' could sometimes fail on *Note
     `NDB': mysql-cluster. tables due to the use of unitialized data
     when checking for duplicate keys to be ignored.  (Bug #25817)

   * *MySQL Cluster*: When inserting a row into an *Note `NDB':
     mysql-cluster.  table with a duplicate value for a nonprimary
     unique key, the error issued would reference the wrong key.

     This improves on an initial fix for this issue made in MySQL
     5.0.30 and MySQL 5.0.33 (Bug #21072)

   * *Replication*: A *Note `CREATE USER': create-user, *Note `DROP
     USER': drop-user, or *Note `RENAME USER': rename-user. statement
     that fails on the master, or that is a duplicate of any of these
     statements, is no longer written to the binlog; previously, either
     of these occurrences could cause the slave to fail.  (Bug #33862)
     See also Bug #29749.

   * *Replication*: *Note `SHOW BINLOG EVENTS': show-binlog-events.
     could fail when the binlog contained one or more events whose size
     was close to the value of `max_allowed_packet'.  (Bug #33413)

   * *Replication*: SQL statements containing comments using `--'
     syntax were not replayable by *Note `mysqlbinlog': mysqlbinlog,
     even though such statements replicated correctly.  (Bug #32205)

   * *Replication*: It was possible for the name of the relay log file
     to exceed the amount of memory reserved for it, possibly leading
     to a crash of the server.  (Bug #31836) See also Bug #28597.

   * *Replication*: Corruption of log events caused the server to crash
     on 64-bit Linux systems having 4 GB or more of memory.  (Bug
     #31793)

   * *Replication*: Use of the `@@hostname' system variable in inserts
     in `mysql_system_tables_data.sql' did not replicate. The
     workaround is to select its value into a user variable (which does
     replicate) and insert that.  (Bug #31167)

   * *Replication*: Issuing a *Note `DROP VIEW': drop-view. statement
     caused replication to fail if the view did not actually exist.
     (Bug #30998)

   * *Replication*: One thread could read uninitialized memory from the
     stack of another thread. This issue was only known to occur in a
     *Note `mysqld': mysqld. process acting as both a master and a
     slave.  (Bug #30752)

   * *Replication*: Replication of *Note `LOAD DATA INFILE': load-data.
     could fail when `read_buffer_size' was larger than
     `max_allowed_packet'.  (Bug #30435)

   * *Replication*: Setting `server_id' did not update its value for
     the current session.  (Bug #28908)

   * *Replication*: Due a previous change in how the default name and
     location of the binary log file were determined, replication failed
     following some upgrades.  (Bug #28597, Bug #28603) See also Bug
     #31836.

     This regression was introduced by Bug #20166.

   * *Replication*: Stored procedures having *Note `BIT': numeric-types.
     parameters were not replicated correctly.  (Bug #26199)

   * *Replication*: Issuing *Note `SHOW SLAVE STATUS':
     show-slave-status. as *Note `mysqld': mysqld. was shutting down
     could cause a crash.  (Bug #26000)

   * *Replication*: An *Note `UPDATE': update. statement using a stored
     function that modified a nontransactional table was not logged if
     it failed. This caused the copy of the nontransactional table on
     the master have a row that the copy on the slave did not.

     In addition, when an *Note `INSERT ... ON DUPLICATE KEY UPDATE':
     insert-on-duplicate. statement encountered a duplicate key
     constraint, but the *Note `UPDATE': update. did not actually change
     any data, the statement was not logged. As a result of this fix,
     such statements are now treated the same for logging purposes as
     other *Note `UPDATE': update. statements, and so are written to
     the binary log.  (Bug #23333) See also Bug #12713.

   * *Replication*: A replication slave sometimes failed to reconnect
     because it was unable to run *Note `SHOW SLAVE HOSTS':
     show-slave-hosts.  It was not necessary to run this statement on
     slaves (since the master should track connection IDs), and the
     execution of this statement by slaves was removed.  (Bug #21132)
     See also Bug #13963, Bug #21869.

   * The server crashed when executing a query that had a subquery
     containing an equality X=Y where Y referred to a named select list
     expression from the parent select. The server crashed when trying
     to use the X=Y equality for `ref'-based access.  (Bug #33794)

   * Use of uninitialized memory for `filesort' in a subquery caused a
     server crash.  (Bug #33675)

   * The server could crash when *Note `REPEAT': repeat-statement.  or
     another control instruction was used in conjunction with labels
     and a *Note `LEAVE': leave-statement.  instruction.  (Bug #33618)

   * The parser permitted control structures in compound statements to
     have mismatched beginning and ending labels.  (Bug #33618)

   * `SET GLOBAL myisam_max_sort_file_size=DEFAULT' set
     `myisam_max_sort_file_size' to an incorrect value.  (Bug #33382)
     See also Bug #31177.

   * *Note `CREATE TABLE ... SELECT': create-table. created tables that
     for date columns used the obsolete `Field_date' type instead of
     `Field_newdate'.  (Bug #33256)

   * For *Note `DECIMAL': numeric-types. columns used with the
     `ROUND(X,D)' or `TRUNCATE(X,D)' function with a nonconstant value
     of D, adding an `ORDER BY' for the function result produced
     misordered output.  (Bug #33143) See also Bug #33402, Bug #30617.

   * Some valid *Note `SELECT': select. statements could not be used as
     views due to incorrect column reference resolution.  (Bug #33133)

   * The fix for Bug #11230 and Bug #26215 introduced a significant
     input-parsing slowdown for the *Note `mysql': mysql. client.  This
     has been corrected.  (Bug #33057)

   * *Note `UNION': union. constructs cannot contain *Note `SELECT ...
     INTO': select. except in the final *Note `SELECT': select.
     However, if a *Note `UNION': union. was used in a subquery and an
     `INTO' clause appeared in the top-level query, the parser
     interpreted it as having appeared in the *Note `UNION': union. and
     raised an error.  (Bug #32858)

   * The correct data type for a `NULL' column resulting from a *Note
     `UNION': union. could be determined incorrectly in some cases: 1)
     Not correctly inferred as `NULL' depending on the number of
     selects; 2) Not inferred correctly as `NULL' if one select used a
     subquery.  (Bug #32848)

   * An `ORDER BY' query using `IS NULL' in the `WHERE' clause did not
     return correct results.  (Bug #32815)

   * For queries containing `GROUP_CONCAT(DISTINCT COL_LIST ORDER BY
     COL_LIST)', there was a limitation that the `DISTINCT' columns had
     to be the same as `ORDER BY' columns. Incorrect results could be
     returned if this was not true.  (Bug #32798)

   * The `LAST_DAY()' function returns a *Note `DATE': datetime. value,
     but internally the value did not have the time fields zeroed and
     calculations involving the value could return incorrect results.
     (Bug #32770)

   * Use of the `cp932' character set with `CAST()' in an `ORDER BY'
     clause could cause a server crash.  (Bug #32726)

   * A subquery using an `IS NULL' check of a column defined as `NOT
     NULL' in a table used in the `FROM' clause of the outer query
     produced an invalid result.  (Bug #32694)

   * Specifying a nonexistent column for an *Note `INSERT DELAYED':
     insert-delayed. statement caused a server crash rather than
     producing an error.  (Bug #32676)

   * Use of `CLIENT_MULTI_QUERIES' caused `libmysqld' to crash.  (Bug
     #32624)

   * The `INTERVAL()' function incorrectly handled `NULL' values in the
     value list.  (Bug #32560)

   * Use of a `NULL'-returning `GROUP BY' expression in conjunction
     with `WITH ROLLUP' could cause a server crash.  (Bug #32558) See
     also Bug #31095.

   * A `SELECT ... GROUP BY BIT_COLUMN' query failed with an assertion
     if the length of the *Note `BIT': numeric-types. column used for
     the `GROUP BY' was not an integer multiple of 8.  (Bug #32556)

   * Using `SELECT INTO OUTFILE' with 8-bit `ENCLOSED BY' characters
     led to corrupted data when the data was reloaded using LOAD DATA
     INFILE. This was because `SELECT INTO OUTFILE' failed to escape
     the 8-bit characters.  (Bug #32533)

   * For *Note `FLUSH TABLES WITH READ LOCK': flush, the server failed
     to properly detect write-locked tables when running with
     low-priority updates, resulting in a crash or deadlock.  (Bug
     #32528)

   * A build problem introduced in MySQL 5.0.52 was resolved: The x86
     32-bit Intel `icc'-compiled server binary had unwanted dependences
     on Intel `icc' runtime libraries.  (Bug #32514)

   * The rules for valid column names were being applied differently
     for base tables and views.  (Bug #32496)

   * Sending several *Note `KILL QUERY': kill. statements to target a
     connection running `SELECT SLEEP()' could freeze the server.  (Bug
     #32436)

   * `ssl-cipher' values in option files were not being read by
     `libmysqlclient'.  (Bug #32429)

   * Repeated execution of a query containing a *Note `CASE':
     case-statement.  expression and numerous `AND' and `OR' relations
     could crash the server. The root cause of the issue was determined
     to be that the internal `SEL_ARG' structure was not properly
     initialized when created.  (Bug #32403)

   * Referencing within a subquery an alias used in the *Note `SELECT':
     select. list of the outer query was incorrectly permitted.  (Bug
     #32400)

   * An `ORDER BY' query on a view created using a `FEDERATED' table as
     a base table caused the server to crash.  (Bug #32374)

   * Comparison of a `BIGINT NOT NULL' column with a constant
     arithmetic expression that evaluated to NULL mistakenly caused the
     error `Column '...' cannot be null' (error 1048).  (Bug #32335)

   * Assigning a 65,536-byte string to a *Note `TEXT': blob. column
     (which can hold a maximum of 65,535 bytes) resulted in truncation
     without a warning. Now a truncation warning is generated.  (Bug
     #32282)

   * `MIN()' and `MAX()' could return incorrect results when an index
     was present if a loose index scan was used.  (Bug #32268)

   * Memory corruption could occur due to large index map in `Range
     checked for each record' status reported by *Note `EXPLAIN
     SELECT': explain. The problem was based in an incorrectly
     calculated length of the buffer used to store a hexadecimal
     representation of an index map, which could result in buffer
     overrun and stack corruption under some circumstances.  (Bug
     #32241)

   * Various test program cleanups were made: 1) `mytest' and
     `libmysqltest' were removed. 2) `bug25714' displays an error
     message when invoked with incorrect arguments or the `--help'
     option. 3) `mysql_client_test' exits cleanly with a proper error
     status.  (Bug #32221)

   * The default grant tables on Windows contained information for host
     `production.mysql.com', which should not be there.  (Bug #32219)

   * Under certain conditions, the presence of a `GROUP BY' clause
     could cause an `ORDER BY' clause to be ignored.  (Bug #32202)

   * For comparisons of the form DATE_COL OP DATETIME_CONST (where OP is
     `=', `<', `>', `<=', or `>='), the comparison is done using *Note
     `DATETIME': datetime. values, per the fix for Bug #27590. However
     that fix caused any index on DATE_COL not to be used and
     compromised performance. Now the index is used again.  (Bug #32198)

   * *Note `DATETIME': datetime. arguments specified in numeric form
     were treated by `DATE_ADD()' as *Note `DATE': datetime. values.
     (Bug #32180)

   * `InnoDB' does not support `SPATIAL' indexes, but could crash when
     asked to handle one. Now an error is returned.  (Bug #32125)

   * The server crashed on optimizations involving a join of *Note
     `INT': numeric-types. and *Note `MEDIUMINT': numeric-types.
     columns and a system variable in the `WHERE' clause.  (Bug #32103)

   * With `lower_case_table_names' set, `CREATE TABLE LIKE' was treated
     differently by `libmysqld' than by the nonembedded server.  (Bug
     #32063)

   * Within a subquery, *Note `UNION': union. was handled differently
     than at the top level, which could result in incorrect results or
     a server crash.  (Bug #32036, Bug #32051)

   * User-defined functions are not loaded if the server is started
     with the `--skip-grant-tables' option, but the server did not
     properly handle this case and issued an `Out of memory' error
     message instead.  (Bug #32020)

   * `HOUR()', `MINUTE()', and `SECOND()' could return nonzero values
     for *Note `DATE': datetime. arguments.  (Bug #31990)

   * A column with malformed multi-byte characters could cause the
     full-text parser to go into an infinite loop.  (Bug #31950)

   * Changing the SQL mode to cause dates with `zero' parts to be
     considered invalid (such as `'1000-00-00'') could result in
     indexed and nonindexed searches returning different results for a
     column that contained such dates.  (Bug #31928)

   * In debug builds, testing the result of an `IN' subquery against
     `NULL' caused an assertion failure.  (Bug #31884)

   * `mysql-test-run.pl' sometimes set up test scenarios in which the
     same port number was passed to multiple servers, causing one of
     them to be unable to start.  (Bug #31880)

   * Comparison results for `BETWEEN' were different from those for
     operators like `<' and `>' for *Note `DATETIME': datetime.-like
     values with trailing extra characters such as `'2007-10-01 00:00:00
     GMT-6''. `BETWEEN' treated the values as *Note `DATETIME':
     datetime, whereas the other operators performed a binary-string
     comparison. Now they all uniformly use a *Note `DATETIME':
     datetime.  comparison, but generate warnings for values with
     trailing garbage.  (Bug #31800)

   * Name resolution for correlated subqueries and `HAVING' clauses
     failed to distinguish which of two was being performed when there
     was a reference to an outer aliased field. This could result in
     error messages about a `HAVING' clause for queries that had no such
     clause.  (Bug #31797)

   * The server could crash during `filesort' for `ORDER BY' based on
     expressions with `INET_NTOA()' or `OCT()' if those functions
     returned `NULL'.  (Bug #31758)

   * For a fatal error during a filesort in `find_all_keys()', the
     error was returned without the necessary handler uninitialization,
     causing an assertion failure.  (Bug #31742)

   * The examined-rows count was not incremented for `const' queries.
     (Bug #31700)

   * The *Note `mysql_change_user()': mysql-change-user. C API function
     was subject to buffer overflow.  (Bug #31669)

   * For *Note `SELECT ... INTO OUTFILE': select, if the `ENCLOSED BY'
     string is empty and the `FIELDS TERMINATED BY' string started with
     a special character (one of `n', `t', `r', `b', `0', `Z', or `N'),
     every occurrence of the character within field values would be
     duplicated.  (Bug #31663)

   * *Note `SHOW COLUMNS': show-columns. and *Note `DESCRIBE':
     describe. displayed `null' as the column type for a view with no
     valid definer. This caused *Note `mysqldump': mysqldump. to
     produce a nonreloadable dump file for the view.  (Bug #31662)

   * The *Note `mysqlbug': mysqlbug. script did not include the correct
     values of `CFLAGS' and `CXXFLAGS' that were used to configure the
     distribution.  (Bug #31644)

   * `ucs2' does not work as a client character set, but attempts to
     use it as such were not rejected. Now `character_set_client'
     cannot be set to `ucs2'. This also affects statements such as `SET
     NAMES' and `SET CHARACTER SET'.  (Bug #31615)

   * A buffer used when setting variables was not dimensioned to
     accommodate the trailing `'\0'' byte, so a single-byte buffer
     overrun was possible.  (Bug #31588)

   * `HAVING' could treat lettercase of table aliases incorrectly if
     `lower_case_table_names' was enabled.  (Bug #31562)

   * The fix for Bug #24989 introduced a problem such that a `NULL'
     thread handler could be used during a rollback operation. This
     problem is unlikely to be seen in practice.  (Bug #31517)

   * Killing a `CREATE TABLE ... LIKE' statement that was waiting for a
     name lock caused a server crash. When the statement was killed,
     the server attempted to release locks that were not held.  (Bug
     #31479)

   * The length of the result from `IFNULL()' could be calculated
     incorrectly because the sign of the result was not taken into
     account.  (Bug #31471)

   * Queries that used the `ref' access method or index-based subquery
     execution over indexes that have *Note `DECIMAL': numeric-types.
     columns could fail with an error `Column COL_NAME cannot be null'.
     (Bug #31450)

   * `SELECT 1 REGEX NULL' caused an assertion failure for debug
     servers.  (Bug #31440)

   * Executing `RENAME' while tables were open for use with *Note
     `HANDLER': handler. statements could cause a server crash.  (Bug
     #31409)

   * `mysql-test-run.pl' tried to create files in a directory where it
     could not be expected to have write permission. `mysqltest' created
     `.reject' files in a directory other than the one where test
     results go.  (Bug #31398)

   * *Note `DROP USER': drop-user. caused an increase in memory usage.
     (Bug #31347)

   * For an almost-full `MyISAM' table, an insert that failed could
     leave the table in a corrupt state.  (Bug #31305)

   * *Note `myisamchk --unpack': myisamchk. could corrupt a table that
     when unpacked has static (fixed-length) row format.  (Bug #31277)

   * `CONVERT(VAL, DATETIME)' would fail on invalid input, but
     processing was not aborted for the `WHERE' clause, leading to a
     server crash.  (Bug #31253)

   * Allocation of an insufficiently large group-by buffer following
     creation of a temporary table could lead to a server crash.  (Bug
     #31249)

   * Use of `DECIMAL(N, N) ZEROFILL' in `GROUP_CONCAT()' could cause a
     server crash.  (Bug #31227)

   * Server variables could not be set to their current values on Linux
     platforms.  (Bug #31177) See also Bug #6958.

   * With small values of `myisam_sort_buffer_size', *Note `REPAIR
     TABLE': repair-table. for `MyISAM' tables could cause a server
     crash.  (Bug #31174)

   * If `MAKETIME()' returned `NULL' when used in an `ORDER BY' that
     was evaluated using `filesort', a server crash could result.  (Bug
     #31160)

   * Full-text searches on `ucs2' columns caused a server crash.
     (`FULLTEXT' indexes on `ucs2' columns cannot be used, but it
     should be possible to perform `IN BOOLEAN MODE' searches on `ucs2'
     columns without a crash.)  (Bug #31159)

   * Data in *Note `BLOB': blob. or `GEOMETRY' columns could be cropped
     when performing a *Note `UNION': union. query.  (Bug #31158)

   * An assertion designed to detect a bug in the `ROLLUP'
     implementation would incorrectly be triggered when used in a
     subquery context with noncacheable statements.  (Bug #31156)

   * Selecting spatial types in a *Note `UNION': union. could cause a
     server crash.  (Bug #31155)

   * Use of `GROUP_CONCAT(DISTINCT BIT_COLUMN)' caused an assertion
     failure.  (Bug #31154)

   * The server crashed in the parser when running out of memory.
     Memory handling in the parser has been improved to gracefully
     return an error when out-of-memory conditions occur in the parser.
     (Bug #31153)

   * MySQL declares a `UNIQUE' key as a `PRIMARY' key if it doesn't have
     `NULL' columns and is not a partial key, and the `PRIMARY' key
     must alway be the first key.  However, in some cases, a nonfirst
     key could be reported as `PRIMARY', leading to an assert failure by
     `InnoDB'. This is fixed by correcting the key sort order.  (Bug
     #31137)

   * `GROUP BY NULL WITH ROLLUP' could cause a server crash.  (Bug
     #31095) See also Bug #32558.

   * `REGEXP' operations could cause a server crash for character sets
     such as `ucs2'.  Now the arguments are converted to `utf8' if
     possible, to permit correct results to be produced if the
     resulting strings contain only 8-bit characters.  (Bug #31081)

   * Internal conversion routines could fail for several multi-byte
     character sets (`big5', `cp932', `euckr', `gb2312', `sjis') for
     empty strings or during evaluation of `SOUNDS LIKE'.  (Bug #31069,
     Bug #31070)

   * Many nested subqueries in a single query could led to excessive
     memory consumption and possibly a crash of the server.  (Bug
     #31048)

   * The `MOD()' function and the `%' operator crashed the server for a
     divisor less than 1 with a very long fractional part.  (Bug #31019)

   * On Windows, the `pthread_mutex_trylock()' implementation was
     incorrect.  (Bug #30992)

   * A character set introducer followed by a hexadecimal or bit-value
     literal did not check its argument and could return an ill-formed
     result for invalid input.  (Bug #30986)

   * `CHAR(STR USING CHARSET)' did not check its argument and could
     return an ill-formed result for invalid input.  (Bug #30982)

   * The result from `CHAR(STR USING ucs2') did not add a leading 0x00
     byte for input strings with an odd number of bytes.  (Bug #30981)

   * The `GeomFromText()' function could cause a server crash if the
     first argument was `NULL' or the empty string.  (Bug #30955)

   * `MAKEDATE()' incorrectly moved year values in the 100 to 200 range
     into the 1970 to 2069 range.  (This is legitimate for 00 to 99,
     but three-digit years should be used unchanged.)  (Bug #30951)

   * When invoked with constant arguments, `STR_TO_DATE()' could use a
     cached value for the format string and return incorrect results.
     (Bug #30942)

   * `GROUP_CONCAT()' returned `','' rather than an empty string when
     the argument column contained only empty strings.  (Bug #30897)

   * `ROUND(X,D)' or `TRUNCATE(X,D)' for nonconstant values of D could
     crash the server if these functions were used in an `ORDER BY'
     that was resolved using `filesort'.  (Bug #30889)

   * For `MEMORY' tables, lookups for `NULL' values in `BTREE' indexes
     could return incorrect results.  (Bug #30885)

   * Calling `NAME_CONST()' with nonconstant arguments triggered an
     assertion failure.  Nonconstant arguments are no longer permitted.
     (Bug #30832)

   * For a spatial column with a regular (non-`SPATIAL') index, queries
     failed if the optimizer tried to use the index.  (Bug #30825)

   * Values for the `--tc-heuristic-recover' option incorrectly were
     treated as values for the `--myisam-stats-method' option.  (Bug
     #30821)

   * The optimizer incorrectly optimized conditions out of the `WHERE'
     clause in some queries involving subqueries and indexed columns.
     (Bug #30788)

   * Improper calculation of `CASE' expression results could lead to
     value truncation.  (Bug #30782)

   * On Windows, the `pthread_mutex_trylock()' implementation was
     incorrect. One symptom was that invalidating the query cache could
     cause a server crash.  (Bug #30768)

   * A multiple-table *Note `UPDATE': update. involving transactional
     and nontransactional tables caused an assertion failure.  (Bug
     #30763)

   * Under some circumstances, *Note `CREATE TABLE ... SELECT':
     create-table. could crash the server or incorrectly report that
     the table row size was too large.  (Bug #30736)

   * Using the `MIN()' or `MAX()' function to select one part of a
     multi-part key could cause a crash when the function result was
     `NULL'.  (Bug #30715)

   * The optimizer could ignore `ORDER BY' in cases when the result set
     is ordered by `filesort', resulting in rows being returned in
     incorrect order.  (Bug #30666)

   * `MyISAM' tables could not exceed 4294967295 (2^32 - 1) rows on
     Windows.  (Bug #30638)

   * `mysql-test-run.pl' could not run *Note `mysqld': mysqld. with
     `root' privileges.  (Bug #30630)

   * For `MEMORY' tables, *Note `DELETE': delete. statements that remove
     rows based on an index read could fail to remove all matching rows.
     (Bug #30590)

   * Using `GROUP BY' on an expression of the form `TIMESTAMP_COL DIV
     NUMBER' caused a server crash due to incorrect calculation of
     number of decimals.  (Bug #30587)

   * The options available to the *Note `CHECK TABLE': check-table.
     statement were also permitted in *Note `OPTIMIZE TABLE':
     optimize-table. and *Note `ANALYZE TABLE': analyze-table.
     statements, but caused corruption during their execution. These
     options were never supported for these statements, and an error is
     now raised if you try to apply these options to these statements.
     (Bug #30495)

   * When expanding a `*' in a `USING' or `NATURAL' join, the check for
     table access for both tables in the join was done using only the
     grant information of the first table.  (Bug #30468)

   * When casting a string value to an integer, cases where the input
     string contained a decimal point and was long enough to overrun
     the `unsigned long long' type were not handled correctly. The
     position of the decimal point was not taken into account which
     resulted in miscalculated numbers and incorrect truncation to
     appropriate SQL data type limits.  (Bug #30453)

   * Versions of *Note `mysqldump': mysqldump. from MySQL 4.1 or higher
     tried to use `START TRANSACTION WITH CONSISTENT SNAPSHOT' if the
     `--single-transaction' and `--master-data' options were given,
     even with servers older than 4.1 that do not support consistent
     snapshots.  (Bug #30444)

   * For `CREATE ... SELECT ... FROM', where the resulting table
     contained indexes, adding `SQL_BUFFER_RESULT' to the *Note
     `SELECT': select. part caused index corruption in the table.  (Bug
     #30384)

   * The optimizer made incorrect assumptions about the value of the
     `is_member' value for user-defined functions, sometimes resulting
     in incorrect ordering of UDF results.  (Bug #30355)

   * Some valid `euc-kr' characters having the second byte in the
     ranges `[0x41..0x5A]' and `[0x61..0x7A]' were rejected.  (Bug
     #30315)

   * Simultaneous *Note `ALTER TABLE': alter-table.  statements for
     `BLACKHOLE' tables caused 100% CPU use due to locking problems.
     (Bug #30294)

   * Setting certain values on a table using a spatial index could
     cause the server to crash.  (Bug #30286)

   * Tables with a `GEOMETRY' column could be marked as corrupt if you
     added a non-`SPATIAL' index on a `GEOMETRY' column.  (Bug #30284)

   * Some `INFORMATION_SCHEMA' tables are intended for internal use,
     but could be accessed by using *Note `SHOW': show. statements.
     (Bug #30079)

   * On some 64-bit systems, inserting the largest negative value into
     a *Note `BIGINT': numeric-types. column resulted in incorrect data.
     (Bug #30069)

   * Specifying the `--without-geometry' option for `configure' caused
     server compilation to fail.  (Bug #29972)

   * Under some circumstances, a UDF initialization function could be
     passed incorrect argument lengths.  (Bug #29804)

   * `configure' did not find `nss' on some Linux platforms.  (Bug
     #29658)

   * Views were treated as insertable even if some base table columns
     with no default value were omitted from the view definition.
     (This is contrary to the condition for insertability that a view
     must contain all columns in the base table that do not have a
     default value.)  (Bug #29477)

   * The *Note `mysql': mysql. client program now ignores Unicode byte
     order mark (BOM) characters at the beginning of input files.
     Previously, it read them and sent them to the server, resulting in
     a syntax error.

     Presence of a BOM does not cause *Note `mysql': mysql. to change
     its default character set. To do that, invoke *Note `mysql':
     mysql. with an option such as `--default-character-set=utf8'.
     (Bug #29323)

   * For transactional tables, an error during a multiple-table *Note
     `DELETE': delete. statement did not roll back the statement.  (Bug
     #29136)

   * The `log' and `log_slow_queries' system variables were displayed
     by *Note `SHOW VARIABLES': show-variables. but could not be
     accessed in expressions as `@@log' and `@@log_slow_queries'. Also,
     attempting to set them with *Note `SET': set-option.  produced an
     incorrect `Unknown system variable' message. Now these variables
     can be accessed in expressions and attempting to set their values
     produces an error message that the variable is read only.  (Bug
     #29131)

   * Denormalized double-precision numbers cannot be handled properly
     by old MIPS pocessors. For IRIX, this is now handled by enabling a
     mode to use a software workaround.  (Bug #29085)

   * *Note `SHOW VARIABLES': show-variables. did not display the
     `relay_log', `relay_log_index', or `relay_log_info_file' system
     variables.  (Bug #28893)

   * When doing a *Note `DELETE': delete. on a table that involved a
     `JOIN' with *Note `MyISAM': myisam-storage-engine. or *Note
     `MERGE': merge-storage-engine. tables and the `JOIN' referred to
     the same table, the operation could fail reporting `ERROR 1030
     (HY000): Got error 134 from storage engine'. This was because scans
     on the table contents would change because of rows that had
     already been deleted.  (Bug #28837)

   * On Windows, *Note `mysql_upgrade': mysql-upgrade. created temporary
     files in `C:\' and did not clean them up.  (Bug #28774)

   * Index hints specified in view definitions were ignored when using
     the view to select from the base table.  (Bug #28702)

   * Views do not have indexes, so index hints do not apply. Use of
     index hints when selecting from a view is no longer permitted.
     (Bug #28701)

   * After changing the SQL mode to a restrictive value that would make
     already-inserted dates in a column be considered invalid, searches
     returned different results depending on whether the column was
     indexed.  (Bug #28687)

   * The result from `CHAR()' was incorrectly assumed in some contexts
     to return a single-byte result.  (Bug #28550)

   * The parser confused user-defined function (UDF) and stored
     function creation for *Note `CREATE FUNCTION': create-function.
     and required that there be a default database when creating UDFs,
     although there is no such requirement.  (Bug #28318, Bug #29816)

   * The result of a comparison between *Note `VARBINARY':
     binary-varbinary. and *Note `BINARY': binary-varbinary. columns
     differed depending on whether the *Note `VARBINARY':
     binary-varbinary. column was indexed.  (Bug #28076)

   * The metadata in some `MYSQL_FIELD' members could be incorrect when
     a temporary table was used to evaluate a query.  (Bug #27990)

   * An `ORDER BY' at the end of a *Note `UNION': union. affected
     individual *Note `SELECT': select. statements rather than the
     overall query result.  (Bug #27848)

   * *Note `comp_err': comp-err. created files with permissions such
     that they might be inaccessible during `make install' operations.
     (Bug #27789)

   * The anonymous accounts were not being created during MySQL
     installation.  (Bug #27692)

   * A race condition between killing a statement and the thread
     executing the statement could lead to a situation such that the
     binary log contained an event indicating that the statement was
     killed, whereas the statement actually executed to completion.
     (Bug #27571)

   * Some queries using the `NAME_CONST()' function failed to return
     either a result or an error to the client, causing it to hang.
     This was due to the fact that there was no check to insure that
     both arguments to this function were constant expressions.  (Bug
     #27545, Bug #32559)

   * With the `read_only' system variable enabled, *Note `CREATE
     DATABASE': create-database.  and *Note `DROP DATABASE':
     drop-database. were permitted to users who did not have the
     `SUPER' privilege.  (Bug #27440)

   * *Note `resolveip': resolveip. failed to produce correct results
     for host names that begin with a digit.  (Bug #27427)

   * *Note `mysqld': mysqld. sometimes miscalculated the number of
     digits required when storing a floating-point number in a *Note
     `CHAR': char. column. This caused the value to be truncated, or
     (when using a debug build) caused the server to crash.  (Bug
     #26788) See also Bug #12860.

   * *Note `mysqlcheck -A -r': mysqlcheck. did not correctly identify
     all tables that needed repairing.  (Bug #25347)

   * If the expected precision of an arithmetic expression exceeded the
     maximum precision supported by MySQL, the precision of the result
     was reduced by an unpredictable or arbitrary amount, rather than
     to the maximum precision. In some cases, exceeding the maximum
     supported precision could also lead to a crash of the server.
     (Bug #24907)

   * For Windows Vista, `MySQLInstanceConfig.exe' did not include a
     proper manifest enabling it to run with administrative privileges.
     (Bug #22563) See also Bug #24732.

   * *Note `mysqldumpslow': mysqldumpslow. returned a confusing error
     message when no configuration file was found.  (Bug #20455)

   * Host names sometimes were treated as case sensitive in
     account-management statements (*Note `CREATE USER': create-user,
     *Note `GRANT': grant, *Note `REVOKE': revoke, and so forth).  (Bug
     #19828)

   * The `readline' library has been updated to version 5.2. This
     addresses issues in the *Note `mysql': mysql. client where history
     and editing within the client would fail to work as expected.
     (Bug #18431)

   * The `Aborted_clients' status variable was incremented twice if a
     client exited without calling *Note `mysql_close()': mysql-close.
     (Bug #16918)

   * Clients were ignoring the TCP/IP port number specified as the
     default port using the `--with-tcp-port' configuration option.
     (Bug #15327)

   * Zero-padding of exponent values was not the same across platforms.
     (Bug #12860)

   * Values of types `REAL ZEROFILL', `DOUBLE ZEROFILL', `FLOAT
     ZEROFILL', were not zero-filled when converted to a character
     representation in the C prepared statement API.  (Bug #11589)

   * *Note `mysql': mysql. stripped comments from statements sent to
     the server. Now the `--comments' or `--skip-comments' option can be
     used to control whether to retain or strip comments. The default
     is `--skip-comments'.  (Bug #11230, Bug #26215)

   * If an *Note `INSERT ... SELECT': insert-select. statement is
     executed, and no automatically generated value is successfully
     inserted, then *Note `mysql_insert_id()': mysql-insert-id. returns
     the ID of the last inserted row.

     If no automatically generated value is successfully inserted, then
     *Note `mysql_insert_id()': mysql-insert-id. returns 0.  (Bug #9481)

   * Several buffer-size system variables were either being handled
     incorrectly for large values (for settings larger than 4GB, they
     were truncated to values less than 4GB without a warning), or were
     limited unnecessarily to 4GB even on 64-bit systems. The following
     changes were made:

        * For `key_buffer_size', values larger than 4GB are permitted
          on 64-bit platforms (except Windows, for which large values
          are truncated to 4GB with a warning).

        * For `join_buffer_size', `sort_buffer_size', and
          `myisam_sort_buffer_size', values are limited to 4GB on all
          platforms. Larger values are truncated to 4GB with a warning.

     In addition, settings for `read_buffer_size' and
     `read_rnd_buffer_size' are limited to 2GB on all platforms. Larger
     values are truncated to 2GB with a warning.  (Bug #5731, Bug
     #29419, Bug #29446)

   * Executing `DISABLE KEYS' and `ENABLE KEYS' on a nonempty table
     would cause the size of the index file for the table to grow
     considerable. This was because the `DISABLE KEYS' operation would
     only mark the existing index, without deleting the index blocks.
     The `ENABLE KEYS' operation would re-create the index, adding new
     blocks, while the previous index blocks would remain. Existing
     indexes are now dropped and recreated when the `ENABLE KEYS'
     statement is executed.  (Bug #4692)


File: manual.info,  Node: news-5-0-56,  Next: news-5-0-54a,  Prev: news-5-0-56sp1,  Up: news-5-0-x

D.1.40 Changes in MySQL Enterprise 5.0.56 [MRU] (06 February 2008)
------------------------------------------------------------------

This is a _Monthly Rapid Update_ release of the MySQL Enterprise Server
5.0.

This section documents all changes and bugfixes that have been applied
since the last MySQL Enterprise Server release (5.0.54).  If you would
like to receive more fine-grained and personalized _update alerts_
about fixes that are relevant to the version and features you use,
please consider subscribing to _MySQL Enterprise_ (a commercial MySQL
offering). For more details please see
http://www.mysql.com/products/enterprise/advisors.html.

*Bugs Fixed*

   * *Important Change*: *MySQL Cluster*: `AUTO_INCREMENT' columns had
     the following problems when used in *Note `NDB': mysql-cluster.
     tables:

        * The `AUTO_INCREMENT' counter was not updated correctly when
          such a column was updated.

        * `AUTO_INCREMENT' values were not prefetched beyond statement
          boundaries.

        * `AUTO_INCREMENT' values were not handled correctly with *Note
          `INSERT IGNORE': insert. statements.

        * After being set, `ndb_autoincrement_prefetch_sz' showed a
          value of 1, regardless of the value it had actually been set
          to.

     As part of this fix, the behavior of
     `ndb_autoincrement_prefetch_sz' has changed. Setting this to less
     than 32 no longer has any effect on prefetching within statements
     (where IDs are now always obtained in batches of 32 or more), but
     only between statements. The default value for this variable has
     also changed, and is now `1'.  (Bug #25176, Bug #31956, Bug #32055)

   * *Important Change*: *Replication*: When the master crashed during
     an update on a transactional table while in `autocommit' mode, the
     slave failed. This fix causes every transaction (including
     `autocommit' transactions) to be recorded in the binary log as
     starting with a *Note `BEGIN': commit. and ending with a *Note
     `COMMIT': commit. or *Note `ROLLBACK': commit.

     *Note*:

     The current fix does _not_ cause nontransactional changes to be
     wrapped in *Note `BEGIN': commit ...  *Note `COMMIT': commit. or
     *Note `BEGIN': commit ...  *Note `ROLLBACK': commit.  when written
     to the binary log. For this purpose, any statements affecting
     tables using a nontransactional storage engine such as *Note
     `MyISAM': myisam-storage-engine. are regarded as nontransactional,
     even when `autocommit' is enabled.

     (Bug #26395) See also Bug #29288, Bug #49522.

   * *Replication*: *Important Note*: Network timeouts between the
     master and the slave could result in corruption of the relay log.
     This fix rectifies a long-standing replication issue when using
     unreliable networks, including replication over wide area networks
     such as the Internet. If you experience reliability issues and see
     many `You have an error in your SQL syntax' errors on replication
     slaves, we strongly recommend that you upgrade to a MySQL version
     which includes this fix.  (Bug #26489)

   * *MySQL Cluster*: An improperly reset internal signal was observed
     as a hang when using events in the *Note `NDB': mysql-cluster. API
     but could result in various errors.  (Bug #33206)

   * *MySQL Cluster*: Incorrectly handled parameters could lead to a
     crash in the Transaction Coordinator during a node failure,
     causing other data nodes to fail.  (Bug #33168)

   * *MySQL Cluster*: The failure of a master node could lead to
     subsequent failures in local checkpointing.  (Bug #32160)

   * *MySQL Cluster*: Primary keys on variable-length columns (such as
     *Note `VARCHAR': char.) did not work correctly.  (Bug #31635)

   * *MySQL Cluster*: When inserting a row into an *Note `NDB':
     mysql-cluster.  table with a duplicate value for a nonprimary
     unique key, the error issued would reference the wrong key.

     This improves on an initial fix for this issue made in MySQL
     5.0.30 and MySQL 5.0.33 (Bug #21072)

   * *Replication*: A *Note `CREATE USER': create-user, *Note `DROP
     USER': drop-user, or *Note `RENAME USER': rename-user. statement
     that fails on the master, or that is a duplicate of any of these
     statements, is no longer written to the binlog; previously, either
     of these occurrences could cause the slave to fail.  (Bug #33862)
     See also Bug #29749.

   * *Replication*: *Note `SHOW BINLOG EVENTS': show-binlog-events.
     could fail when the binlog contained one or more events whose size
     was close to the value of `max_allowed_packet'.  (Bug #33413)

   * *Replication*: SQL statements containing comments using `--'
     syntax were not replayable by *Note `mysqlbinlog': mysqlbinlog,
     even though such statements replicated correctly.  (Bug #32205)

   * *Replication*: Issuing a *Note `DROP VIEW': drop-view. statement
     caused replication to fail if the view did not actually exist.
     (Bug #30998)

   * *Replication*: Replication of *Note `LOAD DATA INFILE': load-data.
     could fail when `read_buffer_size' was larger than
     `max_allowed_packet'.  (Bug #30435)

   * *Replication*: Setting `server_id' did not update its value for
     the current session.  (Bug #28908)

   * The server crashed when executing a query that had a subquery
     containing an equality X=Y where Y referred to a named select list
     expression from the parent select. The server crashed when trying
     to use the X=Y equality for `ref'-based access.  (Bug #33794)

   * Use of uninitialized memory for `filesort' in a subquery caused a
     server crash.  (Bug #33675)

   * The server could crash when *Note `REPEAT': repeat-statement.  or
     another control instruction was used in conjunction with labels
     and a *Note `LEAVE': leave-statement.  instruction.  (Bug #33618)

   * The parser permitted control structures in compound statements to
     have mismatched beginning and ending labels.  (Bug #33618)

   * `SET GLOBAL myisam_max_sort_file_size=DEFAULT' set
     `myisam_max_sort_file_size' to an incorrect value.  (Bug #33382)
     See also Bug #31177.

   * *Note `CREATE TABLE ... SELECT': create-table. created tables that
     for date columns used the obsolete `Field_date' type instead of
     `Field_newdate'.  (Bug #33256)

   * For *Note `DECIMAL': numeric-types. columns used with the
     `ROUND(X,D)' or `TRUNCATE(X,D)' function with a nonconstant value
     of D, adding an `ORDER BY' for the function result produced
     misordered output.  (Bug #33143) See also Bug #33402, Bug #30617.

   * Some valid *Note `SELECT': select. statements could not be used as
     views due to incorrect column reference resolution.  (Bug #33133)

   * The fix for Bug #11230 and Bug #26215 introduced a significant
     input-parsing slowdown for the *Note `mysql': mysql. client.  This
     has been corrected.  (Bug #33057)

   * *Note `UNION': union. constructs cannot contain *Note `SELECT ...
     INTO': select. except in the final *Note `SELECT': select.
     However, if a *Note `UNION': union. was used in a subquery and an
     `INTO' clause appeared in the top-level query, the parser
     interpreted it as having appeared in the *Note `UNION': union. and
     raised an error.  (Bug #32858)

   * The correct data type for a `NULL' column resulting from a *Note
     `UNION': union. could be determined incorrectly in some cases: 1)
     Not correctly inferred as `NULL' depending on the number of
     selects; 2) Not inferred correctly as `NULL' if one select used a
     subquery.  (Bug #32848)

   * For queries containing `GROUP_CONCAT(DISTINCT COL_LIST ORDER BY
     COL_LIST)', there was a limitation that the `DISTINCT' columns had
     to be the same as `ORDER BY' columns. Incorrect results could be
     returned if this was not true.  (Bug #32798)

   * `HOUR()', `MINUTE()', and `SECOND()' could return nonzero values
     for *Note `DATE': datetime. arguments.  (Bug #31990)

   * `mysql-test-run.pl' sometimes set up test scenarios in which the
     same port number was passed to multiple servers, causing one of
     them to be unable to start.  (Bug #31880)

   * Name resolution for correlated subqueries and `HAVING' clauses
     failed to distinguish which of two was being performed when there
     was a reference to an outer aliased field. This could result in
     error messages about a `HAVING' clause for queries that had no such
     clause.  (Bug #31797)

   * `ROUND(X,D)' or `TRUNCATE(X,D)' for nonconstant values of D could
     crash the server if these functions were used in an `ORDER BY'
     that was resolved using `filesort'.  (Bug #30889)

   * Views were treated as insertable even if some base table columns
     with no default value were omitted from the view definition.
     (This is contrary to the condition for insertability that a view
     must contain all columns in the base table that do not have a
     default value.)  (Bug #29477)

   * An `ORDER BY' at the end of a *Note `UNION': union. affected
     individual *Note `SELECT': select. statements rather than the
     overall query result.  (Bug #27848)

   * With the `read_only' system variable enabled, *Note `CREATE
     DATABASE': create-database.  and *Note `DROP DATABASE':
     drop-database. were permitted to users who did not have the
     `SUPER' privilege.  (Bug #27440)

   * *Note `resolveip': resolveip. failed to produce correct results
     for host names that begin with a digit.  (Bug #27427)

   * *Note `mysqlcheck -A -r': mysqlcheck. did not correctly identify
     all tables that needed repairing.  (Bug #25347)

   * For Windows Vista, `MySQLInstanceConfig.exe' did not include a
     proper manifest enabling it to run with administrative privileges.
     (Bug #22563) See also Bug #24732.

   * *Note `mysqldumpslow': mysqldumpslow. returned a confusing error
     message when no configuration file was found.  (Bug #20455)


File: manual.info,  Node: news-5-0-54a,  Next: news-5-0-54,  Prev: news-5-0-56,  Up: news-5-0-x

D.1.41 Changes in MySQL Enterprise 5.0.54a [MRU] (11 January 2008)
------------------------------------------------------------------

This is a _Monthly Rapid Update_ release of the MySQL Enterprise Server
5.0.

This is a bugfix release that replaces MySQL 5.0.54.

*Bugs Fixed*

   * *Security Fix*: Three vulnerabilities in yaSSL versions 1.7.5 and
     earlier were discovered that could lead to a server crash or
     execution of unauthorized code. The exploit requires a server with
     yaSSL enabled and TCP/IP connections enabled, but does not require
     valid MySQL account credentials. The exploit does not apply to
     OpenSSL.

     *Warning*:

     The proof-of-concept exploit is freely available on the Internet.
     Everyone with a vulnerable MySQL configuration is advised to
     upgrade _immediately_.

     (Bug #33814, CVE-2008-0226, CVE-2008-0227)


File: manual.info,  Node: news-5-0-54,  Next: news-5-0-52,  Prev: news-5-0-54a,  Up: news-5-0-x

D.1.42 Changes in MySQL Enterprise 5.0.54 [MRU] (14 December 2007)
------------------------------------------------------------------

This is a _Monthly Rapid Update_ release of the MySQL Enterprise Server
5.0.

This section documents all changes and bugfixes that have been applied
since the last MySQL Enterprise Server release (5.0.52).  If you would
like to receive more fine-grained and personalized _update alerts_
about fixes that are relevant to the version and features you use,
please consider subscribing to _MySQL Enterprise_ (a commercial MySQL
offering). For more details please see
http://www.mysql.com/products/enterprise/advisors.html.

*Functionality Added or Changed*

   * The `mysql_odbc_escape_string()' C API function has been removed.
     It has multi-byte character escaping issues, doesn't honor the
     `NO_BACKSLASH_ESCAPES' SQL mode and is not needed anymore by
     Connector/ODBC as of 3.51.17.  (Bug #29592) See also Bug #41728.

   * The argument for the `mysql-test-run.pl' `--do-test' and
     `--skip-test' options is now interpreted as a Perl regular
     expression if there is a pattern metacharacter in the argument
     value. This enables more flexible specification of which tests to
     perform or skip.

*Bugs Fixed*

   * *Performance*: `InnoDB' had a race condition for an adaptive hash
     rw-lock waiting for an X-lock. This fix may also provide
     significant speed improvements on systems experiencing problems
     with contention for the adaptive hash index.  (Bug #29560)

   * *Security Enhancement*: It was possible to force an error message
     of excessive length which could lead to a buffer overflow. This
     has been made no longer possible as a security precaution.  (Bug
     #32707)

   * *Incompatible Change*: The MySQL 5.0.50 patch for this bug was
     reverted because it changed the behavior of a General Availability
     MySQL release.  (Bug #30234) See also Bug #27525.

   * *Incompatible Change*: It was possible for option files to be read
     twice at program startup, if some of the standard option file
     locations turned out to be the same directory. Now duplicates are
     removed from the list of files to be read.

     Also, users could not override system-wide settings using
     `~/.my.cnf' because `SYSCONFDIR/my.cnf' was read last. The latter
     file now is read earlier so that `~/.my.cnf' can override
     system-wide settings.

     The fix for this problem had a side effect such that on Unix,
     MySQL programs looked for options in `~/my.cnf' rather than the
     standard location of `~/.my.cnf'. That problem was addressed as
     Bug #38180.  (Bug #20748)

   * *Replication*: It was possible for the name of the relay log file
     to exceed the amount of memory reserved for it, possibly leading
     to a crash of the server.  (Bug #31836) See also Bug #28597.

   * *Replication*: Corruption of log events caused the server to crash
     on 64-bit Linux systems having 4 GB or more of memory.  (Bug
     #31793)

   * *Replication*: One thread could read uninitialized memory from the
     stack of another thread. This issue was only known to occur in a
     *Note `mysqld': mysqld. process acting as both a master and a
     slave.  (Bug #30752)

   * *Replication*: Due a previous change in how the default name and
     location of the binary log file were determined, replication failed
     following some upgrades.  (Bug #28597, Bug #28603) See also Bug
     #31836.

     This regression was introduced by Bug #20166.

   * *Replication*: Stored procedures having *Note `BIT': numeric-types.
     parameters were not replicated correctly.  (Bug #26199)

   * *Replication*: Issuing *Note `SHOW SLAVE STATUS':
     show-slave-status. as *Note `mysqld': mysqld. was shutting down
     could cause a crash.  (Bug #26000)

   * *Replication*: An *Note `UPDATE': update. statement using a stored
     function that modified a nontransactional table was not logged if
     it failed. This caused the copy of the nontransactional table on
     the master have a row that the copy on the slave did not.

     In addition, when an *Note `INSERT ... ON DUPLICATE KEY UPDATE':
     insert-on-duplicate. statement encountered a duplicate key
     constraint, but the *Note `UPDATE': update. did not actually change
     any data, the statement was not logged. As a result of this fix,
     such statements are now treated the same for logging purposes as
     other *Note `UPDATE': update. statements, and so are written to
     the binary log.  (Bug #23333) See also Bug #12713.

   * *Replication*: A replication slave sometimes failed to reconnect
     because it was unable to run *Note `SHOW SLAVE HOSTS':
     show-slave-hosts.  It was not necessary to run this statement on
     slaves (since the master should track connection IDs), and the
     execution of this statement by slaves was removed.  (Bug #21132)
     See also Bug #13963, Bug #21869.

   * An `ORDER BY' query using `IS NULL' in the `WHERE' clause did not
     return correct results.  (Bug #32815)

   * The `LAST_DAY()' function returns a *Note `DATE': datetime. value,
     but internally the value did not have the time fields zeroed and
     calculations involving the value could return incorrect results.
     (Bug #32770)

   * Use of the `cp932' character set with `CAST()' in an `ORDER BY'
     clause could cause a server crash.  (Bug #32726)

   * A subquery using an `IS NULL' check of a column defined as `NOT
     NULL' in a table used in the `FROM' clause of the outer query
     produced an invalid result.  (Bug #32694)

   * Specifying a nonexistent column for an *Note `INSERT DELAYED':
     insert-delayed. statement caused a server crash rather than
     producing an error.  (Bug #32676)

   * Use of `CLIENT_MULTI_QUERIES' caused `libmysqld' to crash.  (Bug
     #32624)

   * The `INTERVAL()' function incorrectly handled `NULL' values in the
     value list.  (Bug #32560)

   * Use of a `NULL'-returning `GROUP BY' expression in conjunction
     with `WITH ROLLUP' could cause a server crash.  (Bug #32558) See
     also Bug #31095.

   * A `SELECT ... GROUP BY BIT_COLUMN' query failed with an assertion
     if the length of the *Note `BIT': numeric-types. column used for
     the `GROUP BY' was not an integer multiple of 8.  (Bug #32556)

   * Using `SELECT INTO OUTFILE' with 8-bit `ENCLOSED BY' characters
     led to corrupted data when the data was reloaded using LOAD DATA
     INFILE. This was because `SELECT INTO OUTFILE' failed to escape
     the 8-bit characters.  (Bug #32533)

   * For *Note `FLUSH TABLES WITH READ LOCK': flush, the server failed
     to properly detect write-locked tables when running with
     low-priority updates, resulting in a crash or deadlock.  (Bug
     #32528)

   * Sending several *Note `KILL QUERY': kill. statements to target a
     connection running `SELECT SLEEP()' could freeze the server.  (Bug
     #32436)

   * `ssl-cipher' values in option files were not being read by
     `libmysqlclient'.  (Bug #32429)

   * Repeated execution of a query containing a *Note `CASE':
     case-statement.  expression and numerous `AND' and `OR' relations
     could crash the server. The root cause of the issue was determined
     to be that the internal `SEL_ARG' structure was not properly
     initialized when created.  (Bug #32403)

   * Referencing within a subquery an alias used in the *Note `SELECT':
     select. list of the outer query was incorrectly permitted.  (Bug
     #32400)

   * An `ORDER BY' query on a view created using a `FEDERATED' table as
     a base table caused the server to crash.  (Bug #32374)

   * Comparison of a `BIGINT NOT NULL' column with a constant
     arithmetic expression that evaluated to NULL mistakenly caused the
     error `Column '...' cannot be null' (error 1048).  (Bug #32335)

   * Assigning a 65,536-byte string to a *Note `TEXT': blob. column
     (which can hold a maximum of 65,535 bytes) resulted in truncation
     without a warning. Now a truncation warning is generated.  (Bug
     #32282)

   * `MIN()' and `MAX()' could return incorrect results when an index
     was present if a loose index scan was used.  (Bug #32268)

   * Memory corruption could occur due to large index map in `Range
     checked for each record' status reported by *Note `EXPLAIN
     SELECT': explain. The problem was based in an incorrectly
     calculated length of the buffer used to store a hexadecimal
     representation of an index map, which could result in buffer
     overrun and stack corruption under some circumstances.  (Bug
     #32241)

   * Various test program cleanups were made: 1) `mytest' and
     `libmysqltest' were removed. 2) `bug25714' displays an error
     message when invoked with incorrect arguments or the `--help'
     option. 3) `mysql_client_test' exits cleanly with a proper error
     status.  (Bug #32221)

   * For comparisons of the form DATE_COL OP DATETIME_CONST (where OP is
     `=', `<', `>', `<=', or `>='), the comparison is done using *Note
     `DATETIME': datetime. values, per the fix for Bug #27590. However
     that fix caused any index on DATE_COL not to be used and
     compromised performance. Now the index is used again.  (Bug #32198)

   * *Note `DATETIME': datetime. arguments specified in numeric form
     were treated by `DATE_ADD()' as *Note `DATE': datetime. values.
     (Bug #32180)

   * `InnoDB' does not support `SPATIAL' indexes, but could crash when
     asked to handle one. Now an error is returned.  (Bug #32125)

   * With `lower_case_table_names' set, `CREATE TABLE LIKE' was treated
     differently by `libmysqld' than by the nonembedded server.  (Bug
     #32063)

   * Within a subquery, *Note `UNION': union. was handled differently
     than at the top level, which could result in incorrect results or
     a server crash.  (Bug #32036, Bug #32051)

   * Changing the SQL mode to cause dates with `zero' parts to be
     considered invalid (such as `'1000-00-00'') could result in
     indexed and nonindexed searches returning different results for a
     column that contained such dates.  (Bug #31928)

   * `ucs2' does not work as a client character set, but attempts to
     use it as such were not rejected. Now `character_set_client'
     cannot be set to `ucs2'. This also affects statements such as `SET
     NAMES' and `SET CHARACTER SET'.  (Bug #31615)

   * Killing a `CREATE TABLE ... LIKE' statement that was waiting for a
     name lock caused a server crash. When the statement was killed,
     the server attempted to release locks that were not held.  (Bug
     #31479)

   * *Note `myisamchk --unpack': myisamchk. could corrupt a table that
     when unpacked has static (fixed-length) row format.  (Bug #31277)

   * Server variables could not be set to their current values on Linux
     platforms.  (Bug #31177) See also Bug #6958.

   * Data in *Note `BLOB': blob. or `GEOMETRY' columns could be cropped
     when performing a *Note `UNION': union. query.  (Bug #31158)

   * The server crashed in the parser when running out of memory.
     Memory handling in the parser has been improved to gracefully
     return an error when out-of-memory conditions occur in the parser.
     (Bug #31153)

   * MySQL declares a `UNIQUE' key as a `PRIMARY' key if it doesn't have
     `NULL' columns and is not a partial key, and the `PRIMARY' key
     must alway be the first key.  However, in some cases, a nonfirst
     key could be reported as `PRIMARY', leading to an assert failure by
     `InnoDB'. This is fixed by correcting the key sort order.  (Bug
     #31137)

   * `REGEXP' operations could cause a server crash for character sets
     such as `ucs2'.  Now the arguments are converted to `utf8' if
     possible, to permit correct results to be produced if the
     resulting strings contain only 8-bit characters.  (Bug #31081)

   * Many nested subqueries in a single query could led to excessive
     memory consumption and possibly a crash of the server.  (Bug
     #31048)

   * The optimizer incorrectly optimized conditions out of the `WHERE'
     clause in some queries involving subqueries and indexed columns.
     (Bug #30788)

   * Improper calculation of `CASE' expression results could lead to
     value truncation.  (Bug #30782)

   * A multiple-table *Note `UPDATE': update. involving transactional
     and nontransactional tables caused an assertion failure.  (Bug
     #30763)

   * `mysql-test-run.pl' could not run *Note `mysqld': mysqld. with
     `root' privileges.  (Bug #30630)

   * The options available to the *Note `CHECK TABLE': check-table.
     statement were also permitted in *Note `OPTIMIZE TABLE':
     optimize-table. and *Note `ANALYZE TABLE': analyze-table.
     statements, but caused corruption during their execution. These
     options were never supported for these statements, and an error is
     now raised if you try to apply these options to these statements.
     (Bug #30495)

   * When casting a string value to an integer, cases where the input
     string contained a decimal point and was long enough to overrun
     the `unsigned long long' type were not handled correctly. The
     position of the decimal point was not taken into account which
     resulted in miscalculated numbers and incorrect truncation to
     appropriate SQL data type limits.  (Bug #30453)

   * For `CREATE ... SELECT ... FROM', where the resulting table
     contained indexes, adding `SQL_BUFFER_RESULT' to the *Note
     `SELECT': select. part caused index corruption in the table.  (Bug
     #30384)

   * The optimizer made incorrect assumptions about the value of the
     `is_member' value for user-defined functions, sometimes resulting
     in incorrect ordering of UDF results.  (Bug #30355)

   * Some valid `euc-kr' characters having the second byte in the
     ranges `[0x41..0x5A]' and `[0x61..0x7A]' were rejected.  (Bug
     #30315)

   * Simultaneous *Note `ALTER TABLE': alter-table.  statements for
     `BLACKHOLE' tables caused 100% CPU use due to locking problems.
     (Bug #30294)

   * Tables with a `GEOMETRY' column could be marked as corrupt if you
     added a non-`SPATIAL' index on a `GEOMETRY' column.  (Bug #30284)

   * On some 64-bit systems, inserting the largest negative value into
     a *Note `BIGINT': numeric-types. column resulted in incorrect data.
     (Bug #30069)

   * The *Note `mysql': mysql. client program now ignores Unicode byte
     order mark (BOM) characters at the beginning of input files.
     Previously, it read them and sent them to the server, resulting in
     a syntax error.

     Presence of a BOM does not cause *Note `mysql': mysql. to change
     its default character set. To do that, invoke *Note `mysql':
     mysql. with an option such as `--default-character-set=utf8'.
     (Bug #29323)

   * For transactional tables, an error during a multiple-table *Note
     `DELETE': delete. statement did not roll back the statement.  (Bug
     #29136)

   * Denormalized double-precision numbers cannot be handled properly
     by old MIPS pocessors. For IRIX, this is now handled by enabling a
     mode to use a software workaround.  (Bug #29085)

   * When doing a *Note `DELETE': delete. on a table that involved a
     `JOIN' with *Note `MyISAM': myisam-storage-engine. or *Note
     `MERGE': merge-storage-engine. tables and the `JOIN' referred to
     the same table, the operation could fail reporting `ERROR 1030
     (HY000): Got error 134 from storage engine'. This was because scans
     on the table contents would change because of rows that had
     already been deleted.  (Bug #28837)

   * A race condition between killing a statement and the thread
     executing the statement could lead to a situation such that the
     binary log contained an event indicating that the statement was
     killed, whereas the statement actually executed to completion.
     (Bug #27571)

   * Some queries using the `NAME_CONST()' function failed to return
     either a result or an error to the client, causing it to hang.
     This was due to the fact that there was no check to insure that
     both arguments to this function were constant expressions.  (Bug
     #27545, Bug #32559)

   * *Note `mysqld': mysqld. sometimes miscalculated the number of
     digits required when storing a floating-point number in a *Note
     `CHAR': char. column. This caused the value to be truncated, or
     (when using a debug build) caused the server to crash.  (Bug
     #26788) See also Bug #12860.

   * If the expected precision of an arithmetic expression exceeded the
     maximum precision supported by MySQL, the precision of the result
     was reduced by an unpredictable or arbitrary amount, rather than
     to the maximum precision. In some cases, exceeding the maximum
     supported precision could also lead to a crash of the server.
     (Bug #24907)

   * Zero-padding of exponent values was not the same across platforms.
     (Bug #12860)

   * If an *Note `INSERT ... SELECT': insert-select. statement is
     executed, and no automatically generated value is successfully
     inserted, then *Note `mysql_insert_id()': mysql-insert-id. returns
     the ID of the last inserted row.

     If no automatically generated value is successfully inserted, then
     *Note `mysql_insert_id()': mysql-insert-id. returns 0.  (Bug #9481)


File: manual.info,  Node: news-5-0-52,  Next: news-5-0-51b,  Prev: news-5-0-54,  Up: news-5-0-x

D.1.43 Changes in MySQL Enterprise 5.0.52 [MRU] (30 November 2007)
------------------------------------------------------------------

This is a _Monthly Rapid Update_ release of the MySQL Enterprise Server
5.0.

This section documents all changes and bugfixes that have been applied
since the last MySQL Enterprise Server release (5.0.50).  If you would
like to receive more fine-grained and personalized _update alerts_
about fixes that are relevant to the version and features you use,
please consider subscribing to _MySQL Enterprise_ (a commercial MySQL
offering). For more details please see
http://www.mysql.com/products/enterprise/advisors.html.

*Functionality Added or Changed*

   * *Note `mysqldump': mysqldump. produces a `-- Dump completed on
     DATE' comment at the end of the dump if `--comments' is given. The
     date causes dump files for identical data take at different times
     to appear to be different. The new options `--dump-date' and
     `--skip-dump-date' control whether the date is added to the
     comment.  `--skip-dump-date' suppresses date printing. The default
     is `--dump-date' (include the date in the comment).  (Bug #31077)

   * The default value of the `connect_timeout' system variable was
     increased from 5 to 10 seconds. This might help in cases where
     clients frequently encounter errors of the form `Lost connection
     to MySQL server at 'XXX', system error: ERRNO'.  (Bug #28359)

   * The use of `InnoDB' hash indexes now can be controlled by setting
     the new `innodb_adaptive_hash_index' system variable at server
     startup. By default, this variable is enabled. See *Note
     innodb-adaptive-hash::.

*Bugs Fixed*

   * *Security Fix*: Using *Note `RENAME TABLE': rename-table. against a
     table with explicit `DATA DIRECTORY' and `INDEX DIRECTORY' options
     can be used to overwrite system table information by replacing the
     symbolic link points. the file to which the symlink points.

     MySQL will now return an error when the file to which the symlink
     points already exists.  (Bug #32111, CVE-2007-5969)

   * *Security Fix*: *Note `ALTER VIEW': alter-view. retained the
     original `DEFINER' value, even when altered by another user, which
     could enable that user to gain the access rights of the view. Now
     *Note `ALTER VIEW': alter-view. is permitted only to the original
     definer or users with the `SUPER' privilege.  (Bug #29908)

   * *Security Fix*: When using a `FEDERATED' table, the local server
     could be forced to crash if the remote server returned a result
     with fewer columns than expected.  (Bug #29801)

   * *Incompatible Change*: With `ONLY_FULL_GROUP_BY' SQL mode enabled,
     queries such as `SELECT a FROM t1 HAVING COUNT(*)>2' were not
     being rejected as they should have been.

     This fix results in the following behavior:

        * There is a check against mixing group and nongroup columns
          _only_ when `ONLY_FULL_GROUP_BY' is enabled.

        * This check is done both for the select list and for the
          `HAVING' clause if there is one.

     This behavior differs from previous versions as follows:

        * Previously, the `HAVING' clause was not checked when
          `ONLY_FULL_GROUP_BY' was enabled; now it is checked.

        * Previously, the select list was checked even when
          `ONLY_FULL_GROUP_BY' was not enabled; now it is checked only
          when `ONLY_FULL_GROUP_BY' is enabled.

     (Bug #31794)

   * *Incompatible Change*: It was possible to create a view having a
     column whose name consisted of an empty string or space characters
     only.

     One result of this bug fix is that aliases for columns in the view
     `SELECT' statement are checked to ensure that they are legal
     column names. In particular, the length must be within the maximum
     column length of 64 characters, not the maximum alias length of
     256 characters. This can cause problems for replication or loading
     dump files. For additional information and workarounds, see *Note
     view-restrictions::.  (Bug #27695) See also Bug #31202.

   * *Incompatible Change*: Several type-preserving functions and
     operators returned an incorrect result type that does not match
     their argument types: `COALESCE()', `IF()', `IFNULL()', `LEAST()',
     `GREATEST()', `CASE'. These now aggregate using the precise SQL
     types of their arguments rather than the internal type. In
     addition, the result type of the `STR_TO_DATE()' function is now
     *Note `DATETIME': datetime. by default.  (Bug #27216)

   * *MySQL Cluster*: An uninitialized variable in the *Note `NDB':
     mysql-cluster. storage engine code led to `AUTO_INCREMENT'
     failures when the server was compiled with `gcc' 4.2.1.  (Bug
     #31848) This regression was introduced by Bug #27437.

   * *MySQL Cluster*: An error with an `if' statement in
     `sql/ha_ndbcluster.cc' could potentially lead to an infinite loop
     in case of failure when working with `AUTO_INCREMENT' columns in
     *Note `NDB': mysql-cluster. tables.  (Bug #31810)

   * *MySQL Cluster*: The *Note `NDB': mysql-cluster. storage engine
     code was not safe for strict-alias optimization in `gcc' 4.2.1.
     (Bug #31761)

   * *MySQL Cluster*: Transaction timeouts were not handled well in some
     circumstances, leading to excessive number of transactions being
     aborted unnecessarily.  (Bug #30379)

   * *MySQL Cluster*: In some cases, the cluster managment server
     logged entries multiple times following a restart of *Note
     `ndb_mgmd': mysql-cluster-programs-ndb-mgmd.  (Bug #29565)

   * *MySQL Cluster*: An interpreted program of sufficient size and
     complexity could cause all cluster data nodes to shut down due to
     buffer overruns.  (Bug #29390)

   * *MySQL Cluster*: `UPDATE IGNORE' could sometimes fail on *Note
     `NDB': mysql-cluster. tables due to the use of unitialized data
     when checking for duplicate keys to be ignored.  (Bug #25817)

   * *Replication*: Use of the `@@hostname' system variable in inserts
     in `mysql_system_tables_data.sql' did not replicate. The
     workaround is to select its value into a user variable (which does
     replicate) and insert that.  (Bug #31167)

   * A build problem introduced in MySQL 5.0.52 was resolved: The x86
     32-bit Intel `icc'-compiled server binary had unwanted dependences
     on Intel `icc' runtime libraries.  (Bug #32514)

   * The rules for valid column names were being applied differently
     for base tables and views.  (Bug #32496)

   * The default grant tables on Windows contained information for host
     `production.mysql.com', which should not be there.  (Bug #32219)

   * Under certain conditions, the presence of a `GROUP BY' clause
     could cause an `ORDER BY' clause to be ignored.  (Bug #32202)

   * The server crashed on optimizations involving a join of *Note
     `INT': numeric-types. and *Note `MEDIUMINT': numeric-types.
     columns and a system variable in the `WHERE' clause.  (Bug #32103)

   * User-defined functions are not loaded if the server is started
     with the `--skip-grant-tables' option, but the server did not
     properly handle this case and issued an `Out of memory' error
     message instead.  (Bug #32020)

   * A column with malformed multi-byte characters could cause the
     full-text parser to go into an infinite loop.  (Bug #31950)

   * In debug builds, testing the result of an `IN' subquery against
     `NULL' caused an assertion failure.  (Bug #31884)

   * Comparison results for `BETWEEN' were different from those for
     operators like `<' and `>' for *Note `DATETIME': datetime.-like
     values with trailing extra characters such as `'2007-10-01 00:00:00
     GMT-6''. `BETWEEN' treated the values as *Note `DATETIME':
     datetime, whereas the other operators performed a binary-string
     comparison. Now they all uniformly use a *Note `DATETIME':
     datetime.  comparison, but generate warnings for values with
     trailing garbage.  (Bug #31800)

   * The server could crash during `filesort' for `ORDER BY' based on
     expressions with `INET_NTOA()' or `OCT()' if those functions
     returned `NULL'.  (Bug #31758)

   * For a fatal error during a filesort in `find_all_keys()', the
     error was returned without the necessary handler uninitialization,
     causing an assertion failure.  (Bug #31742)

   * The examined-rows count was not incremented for `const' queries.
     (Bug #31700)

   * The *Note `mysql_change_user()': mysql-change-user. C API function
     was subject to buffer overflow.  (Bug #31669)

   * For *Note `SELECT ... INTO OUTFILE': select, if the `ENCLOSED BY'
     string is empty and the `FIELDS TERMINATED BY' string started with
     a special character (one of `n', `t', `r', `b', `0', `Z', or `N'),
     every occurrence of the character within field values would be
     duplicated.  (Bug #31663)

   * *Note `SHOW COLUMNS': show-columns. and *Note `DESCRIBE':
     describe. displayed `null' as the column type for a view with no
     valid definer. This caused *Note `mysqldump': mysqldump. to
     produce a nonreloadable dump file for the view.  (Bug #31662)

   * The *Note `mysqlbug': mysqlbug. script did not include the correct
     values of `CFLAGS' and `CXXFLAGS' that were used to configure the
     distribution.  (Bug #31644)

   * A buffer used when setting variables was not dimensioned to
     accommodate the trailing `'\0'' byte, so a single-byte buffer
     overrun was possible.  (Bug #31588)

   * `HAVING' could treat lettercase of table aliases incorrectly if
     `lower_case_table_names' was enabled.  (Bug #31562)

   * The fix for Bug #24989 introduced a problem such that a `NULL'
     thread handler could be used during a rollback operation. This
     problem is unlikely to be seen in practice.  (Bug #31517)

   * The length of the result from `IFNULL()' could be calculated
     incorrectly because the sign of the result was not taken into
     account.  (Bug #31471)

   * Queries that used the `ref' access method or index-based subquery
     execution over indexes that have *Note `DECIMAL': numeric-types.
     columns could fail with an error `Column COL_NAME cannot be null'.
     (Bug #31450)

   * `SELECT 1 REGEX NULL' caused an assertion failure for debug
     servers.  (Bug #31440)

   * Executing `RENAME' while tables were open for use with *Note
     `HANDLER': handler. statements could cause a server crash.  (Bug
     #31409)

   * `mysql-test-run.pl' tried to create files in a directory where it
     could not be expected to have write permission. `mysqltest' created
     `.reject' files in a directory other than the one where test
     results go.  (Bug #31398)

   * *Note `DROP USER': drop-user. caused an increase in memory usage.
     (Bug #31347)

   * For an almost-full `MyISAM' table, an insert that failed could
     leave the table in a corrupt state.  (Bug #31305)

   * `CONVERT(VAL, DATETIME)' would fail on invalid input, but
     processing was not aborted for the `WHERE' clause, leading to a
     server crash.  (Bug #31253)

   * Allocation of an insufficiently large group-by buffer following
     creation of a temporary table could lead to a server crash.  (Bug
     #31249)

   * Use of `DECIMAL(N, N) ZEROFILL' in `GROUP_CONCAT()' could cause a
     server crash.  (Bug #31227)

   * With small values of `myisam_sort_buffer_size', *Note `REPAIR
     TABLE': repair-table. for `MyISAM' tables could cause a server
     crash.  (Bug #31174)

   * If `MAKETIME()' returned `NULL' when used in an `ORDER BY' that
     was evaluated using `filesort', a server crash could result.  (Bug
     #31160)

   * Full-text searches on `ucs2' columns caused a server crash.
     (`FULLTEXT' indexes on `ucs2' columns cannot be used, but it
     should be possible to perform `IN BOOLEAN MODE' searches on `ucs2'
     columns without a crash.)  (Bug #31159)

   * An assertion designed to detect a bug in the `ROLLUP'
     implementation would incorrectly be triggered when used in a
     subquery context with noncacheable statements.  (Bug #31156)

   * Selecting spatial types in a *Note `UNION': union. could cause a
     server crash.  (Bug #31155)

   * Use of `GROUP_CONCAT(DISTINCT BIT_COLUMN)' caused an assertion
     failure.  (Bug #31154)

   * `GROUP BY NULL WITH ROLLUP' could cause a server crash.  (Bug
     #31095) See also Bug #32558.

   * Internal conversion routines could fail for several multi-byte
     character sets (`big5', `cp932', `euckr', `gb2312', `sjis') for
     empty strings or during evaluation of `SOUNDS LIKE'.  (Bug #31069,
     Bug #31070)

   * The `MOD()' function and the `%' operator crashed the server for a
     divisor less than 1 with a very long fractional part.  (Bug #31019)

   * On Windows, the `pthread_mutex_trylock()' implementation was
     incorrect.  (Bug #30992)

   * A character set introducer followed by a hexadecimal or bit-value
     literal did not check its argument and could return an ill-formed
     result for invalid input.  (Bug #30986)

   * `CHAR(STR USING CHARSET)' did not check its argument and could
     return an ill-formed result for invalid input.  (Bug #30982)

   * The result from `CHAR(STR USING ucs2') did not add a leading 0x00
     byte for input strings with an odd number of bytes.  (Bug #30981)

   * The `GeomFromText()' function could cause a server crash if the
     first argument was `NULL' or the empty string.  (Bug #30955)

   * `MAKEDATE()' incorrectly moved year values in the 100 to 200 range
     into the 1970 to 2069 range.  (This is legitimate for 00 to 99,
     but three-digit years should be used unchanged.)  (Bug #30951)

   * When invoked with constant arguments, `STR_TO_DATE()' could use a
     cached value for the format string and return incorrect results.
     (Bug #30942)

   * `GROUP_CONCAT()' returned `','' rather than an empty string when
     the argument column contained only empty strings.  (Bug #30897)

   * For `MEMORY' tables, lookups for `NULL' values in `BTREE' indexes
     could return incorrect results.  (Bug #30885)

   * Calling `NAME_CONST()' with nonconstant arguments triggered an
     assertion failure.  Nonconstant arguments are no longer permitted.
     (Bug #30832)

   * For a spatial column with a regular (non-`SPATIAL') index, queries
     failed if the optimizer tried to use the index.  (Bug #30825)

   * Values for the `--tc-heuristic-recover' option incorrectly were
     treated as values for the `--myisam-stats-method' option.  (Bug
     #30821)

   * On Windows, the `pthread_mutex_trylock()' implementation was
     incorrect. One symptom was that invalidating the query cache could
     cause a server crash.  (Bug #30768)

   * Under some circumstances, *Note `CREATE TABLE ... SELECT':
     create-table. could crash the server or incorrectly report that
     the table row size was too large.  (Bug #30736)

   * Using the `MIN()' or `MAX()' function to select one part of a
     multi-part key could cause a crash when the function result was
     `NULL'.  (Bug #30715)

   * The optimizer could ignore `ORDER BY' in cases when the result set
     is ordered by `filesort', resulting in rows being returned in
     incorrect order.  (Bug #30666)

   * `MyISAM' tables could not exceed 4294967295 (2^32 - 1) rows on
     Windows.  (Bug #30638)

   * For `MEMORY' tables, *Note `DELETE': delete. statements that remove
     rows based on an index read could fail to remove all matching rows.
     (Bug #30590)

   * Using `GROUP BY' on an expression of the form `TIMESTAMP_COL DIV
     NUMBER' caused a server crash due to incorrect calculation of
     number of decimals.  (Bug #30587)

   * When expanding a `*' in a `USING' or `NATURAL' join, the check for
     table access for both tables in the join was done using only the
     grant information of the first table.  (Bug #30468)

   * Versions of *Note `mysqldump': mysqldump. from MySQL 4.1 or higher
     tried to use `START TRANSACTION WITH CONSISTENT SNAPSHOT' if the
     `--single-transaction' and `--master-data' options were given,
     even with servers older than 4.1 that do not support consistent
     snapshots.  (Bug #30444)

   * Setting certain values on a table using a spatial index could
     cause the server to crash.  (Bug #30286)

   * Some `INFORMATION_SCHEMA' tables are intended for internal use,
     but could be accessed by using *Note `SHOW': show. statements.
     (Bug #30079)

   * Specifying the `--without-geometry' option for `configure' caused
     server compilation to fail.  (Bug #29972)

   * Under some circumstances, a UDF initialization function could be
     passed incorrect argument lengths.  (Bug #29804)

   * `configure' did not find `nss' on some Linux platforms.  (Bug
     #29658)

   * The `log' and `log_slow_queries' system variables were displayed
     by *Note `SHOW VARIABLES': show-variables. but could not be
     accessed in expressions as `@@log' and `@@log_slow_queries'. Also,
     attempting to set them with *Note `SET': set-option.  produced an
     incorrect `Unknown system variable' message. Now these variables
     can be accessed in expressions and attempting to set their values
     produces an error message that the variable is read only.  (Bug
     #29131)

   * *Note `SHOW VARIABLES': show-variables. did not display the
     `relay_log', `relay_log_index', or `relay_log_info_file' system
     variables.  (Bug #28893)

   * On Windows, *Note `mysql_upgrade': mysql-upgrade. created temporary
     files in `C:\' and did not clean them up.  (Bug #28774)

   * Index hints specified in view definitions were ignored when using
     the view to select from the base table.  (Bug #28702)

   * Views do not have indexes, so index hints do not apply. Use of
     index hints when selecting from a view is no longer permitted.
     (Bug #28701)

   * After changing the SQL mode to a restrictive value that would make
     already-inserted dates in a column be considered invalid, searches
     returned different results depending on whether the column was
     indexed.  (Bug #28687)

   * The result from `CHAR()' was incorrectly assumed in some contexts
     to return a single-byte result.  (Bug #28550)

   * The parser confused user-defined function (UDF) and stored
     function creation for *Note `CREATE FUNCTION': create-function.
     and required that there be a default database when creating UDFs,
     although there is no such requirement.  (Bug #28318, Bug #29816)

   * The result of a comparison between *Note `VARBINARY':
     binary-varbinary. and *Note `BINARY': binary-varbinary. columns
     differed depending on whether the *Note `VARBINARY':
     binary-varbinary. column was indexed.  (Bug #28076)

   * The metadata in some `MYSQL_FIELD' members could be incorrect when
     a temporary table was used to evaluate a query.  (Bug #27990)

   * *Note `comp_err': comp-err. created files with permissions such
     that they might be inaccessible during `make install' operations.
     (Bug #27789)

   * The anonymous accounts were not being created during MySQL
     installation.  (Bug #27692)

   * Host names sometimes were treated as case sensitive in
     account-management statements (*Note `CREATE USER': create-user,
     *Note `GRANT': grant, *Note `REVOKE': revoke, and so forth).  (Bug
     #19828)

   * The `readline' library has been updated to version 5.2. This
     addresses issues in the *Note `mysql': mysql. client where history
     and editing within the client would fail to work as expected.
     (Bug #18431)

   * The `Aborted_clients' status variable was incremented twice if a
     client exited without calling *Note `mysql_close()': mysql-close.
     (Bug #16918)

   * Clients were ignoring the TCP/IP port number specified as the
     default port using the `--with-tcp-port' configuration option.
     (Bug #15327)

   * Values of types `REAL ZEROFILL', `DOUBLE ZEROFILL', `FLOAT
     ZEROFILL', were not zero-filled when converted to a character
     representation in the C prepared statement API.  (Bug #11589)

   * *Note `mysql': mysql. stripped comments from statements sent to
     the server. Now the `--comments' or `--skip-comments' option can be
     used to control whether to retain or strip comments. The default
     is `--skip-comments'.  (Bug #11230, Bug #26215)

   * Several buffer-size system variables were either being handled
     incorrectly for large values (for settings larger than 4GB, they
     were truncated to values less than 4GB without a warning), or were
     limited unnecessarily to 4GB even on 64-bit systems. The following
     changes were made:

        * For `key_buffer_size', values larger than 4GB are permitted
          on 64-bit platforms (except Windows, for which large values
          are truncated to 4GB with a warning).

        * For `join_buffer_size', `sort_buffer_size', and
          `myisam_sort_buffer_size', values are limited to 4GB on all
          platforms. Larger values are truncated to 4GB with a warning.

     In addition, settings for `read_buffer_size' and
     `read_rnd_buffer_size' are limited to 2GB on all platforms. Larger
     values are truncated to 2GB with a warning.  (Bug #5731, Bug
     #29419, Bug #29446)

   * Executing `DISABLE KEYS' and `ENABLE KEYS' on a nonempty table
     would cause the size of the index file for the table to grow
     considerable. This was because the `DISABLE KEYS' operation would
     only mark the existing index, without deleting the index blocks.
     The `ENABLE KEYS' operation would re-create the index, adding new
     blocks, while the previous index blocks would remain. Existing
     indexes are now dropped and recreated when the `ENABLE KEYS'
     statement is executed.  (Bug #4692)


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D.1.44 Changes in MySQL Community Server 5.0.51b (24 April 2008)
----------------------------------------------------------------

This is a bugfix release for the current MySQL Community Server
production release family. It replaces MySQL 5.0.51.

*Bugs Fixed*

   * On Windows, the installer attempted to use JScript to determine
     whether the target data directory already existed. On Windows
     Vista x64, this resulted in an error because the installer was
     attempting to run the JScript in a 32-bit engine, which wasn't
     registered on Vista. The installer no longer uses JScript but
     instead relies on a native WiX command.  (Bug #36103)

   * The MySQL preferences pane did not work to start or stop MySQL on
     Mac OS X 10.5 (Leopard).  (Bug #28854)

   * On Mac OS X, the StartupItem for MySQL did not work.  (Bug #25008)


File: manual.info,  Node: news-5-0-51a,  Next: news-5-0-51,  Prev: news-5-0-51b,  Up: news-5-0-x

D.1.45 Changes in MySQL Community Server 5.0.51a (11 January 2008)
------------------------------------------------------------------

This is a bugfix release for the current MySQL Community Server
production release family. It replaces MySQL 5.0.51.

*Bugs Fixed*

   * *Security Fix*: Three vulnerabilities in yaSSL versions 1.7.5 and
     earlier were discovered that could lead to a server crash or
     execution of unauthorized code. The exploit requires a server with
     yaSSL enabled and TCP/IP connections enabled, but does not require
     valid MySQL account credentials. The exploit does not apply to
     OpenSSL.

     *Warning*:

     The proof-of-concept exploit is freely available on the Internet.
     Everyone with a vulnerable MySQL configuration is advised to
     upgrade _immediately_.

     (Bug #33814, CVE-2008-0226, CVE-2008-0227)

   * *Security Fix*: *Note `ALTER VIEW': alter-view. retained the
     original `DEFINER' value, even when altered by another user, which
     could enable that user to gain the access rights of the view. Now
     *Note `ALTER VIEW': alter-view. is permitted only to the original
     definer or users with the `SUPER' privilege.  (Bug #29908)

   * *Security Fix*: When using a `FEDERATED' table, the local server
     could be forced to crash if the remote server returned a result
     with fewer columns than expected.  (Bug #29801)

   * When running the MySQL Instance Configuration Wizard, a race
     condition could exist that would fail to connect to a newly
     configured instance. This was because *Note `mysqld': mysqld.  had
     not completed the startup process before the next stage of the
     installation process.  (Bug #28628)

   * For Windows Vista, `MySQLInstanceConfig.exe' did not include a
     proper manifest enabling it to run with administrative privileges.
     (Bug #22563) See also Bug #24732.

   * `MySQLInstanceConfig.exe' failed to grant certain privileges to
     the `'root'@'%'' account.  (Bug #17303)


File: manual.info,  Node: news-5-0-51,  Next: news-5-0-50sp1a,  Prev: news-5-0-51a,  Up: news-5-0-x

D.1.46 Changes in MySQL Community Server 5.0.51 (15 November 2007)
------------------------------------------------------------------

This is a bugfix release for the current MySQL Community Server
production release family. It replaces MySQL 5.0.45.

*Functionality Added or Changed*

   * *Incompatible Change*: The parser accepted statements that
     contained `/* ...  */' that were not properly closed with `*/',
     such as `SELECT 1 /* + 2'. Statements that contain unclosed
     `/*'-comments now are rejected with a syntax error.

     This fix has the potential to cause incompatibilities. Because of
     Bug #26302, which caused the trailing `*/' to be truncated from
     comments in views, stored routines, triggers, and events, it is
     possible that objects of those types may have been stored with
     definitions that now will be rejected as syntactically invalid.
     Such objects should be dropped and re-created so that their
     definitions do not contain truncated comments. If a stored object
     definition contains only a single statement (does not use a *Note
     `BEGIN ... END': begin-end. block) and contains a comment within
     the statement, the comment should be moved to follow the statement
     or the object should be rewritten to use a *Note `BEGIN ... END':
     begin-end. block. For example, this statement:

          CREATE PROCEDURE p() SELECT 1 /* my comment */ ;

     Can be rewritten in either of these ways:

          CREATE PROCEDURE p() SELECT 1; /* my comment */
          CREATE PROCEDURE p() BEGIN SELECT 1 /* my comment */ ; END;

     (Bug #28779)

   * *MySQL Cluster*: Mapping of *Note `NDB': mysql-cluster. error
     codes to MySQL storage engine error codes has been improved.  (Bug
     #28423)

   * *MySQL Cluster*: `auto_increment_increment' and
     `auto_increment_offset' are now supported for *Note `NDB':
     mysql-cluster. tables.  (Bug #26342)

   * *MySQL Cluster*: The output from the cluster management client
     showing the progress of data node starts has been improved.  (Bug
     #23354)

   * *Replication*: The `sql_mode', `foreign_key_checks',
     `unique_checks', character set/collations, and `sql_auto_is_null'
     session variables are written to the binary log and honored during
     replication. See *Note binary-log::.

   * Server parser performance was improved for expression parsing by
     lowering the number of state transitions and reductions needed.
     (Bug #30625)

   * Server parser performance was improved for boolean expressions.
     (Bug #30237)

   * If a `MyISAM' table is created with no `DATA DIRECTORY' option, the
     `.MYD' file is created in the database directory. By default, if
     `MyISAM' finds an existing `.MYD' file in this case, it overwrites
     it. The same applies to `.MYI' files for tables created with no
     `INDEX DIRECTORY' option. To suppress this behavior, start the
     server with the new `--keep_files_on_create' option, in which case
     `MyISAM' will not overwrite existing files and returns an error
     instead.  (Bug #29325)

   * MySQL source distributions are now available in Zip format.  (Bug
     #27742)

   * If a `MERGE' table cannot be opened or used because of a problem
     with an underlying table, *Note `CHECK TABLE': check-table. now
     displays information about which table caused the problem.  (Bug
     #26976)

   * The `EXAMPLE' storage engine is now enabled by default.

*Bugs Fixed*

   * *Security Fix*: Using *Note `RENAME TABLE': rename-table. against a
     table with explicit `DATA DIRECTORY' and `INDEX DIRECTORY' options
     can be used to overwrite system table information by replacing the
     symbolic link points. the file to which the symlink points.

     MySQL will now return an error when the file to which the symlink
     points already exists.  (Bug #32111, CVE-2007-5969)

   * *Incompatible Change*: The file `mysqld.exe' was mistakenly
     included in binary distributions between MySQL 5.0.42 and 5.0.48.
     You should use `mysqld-nt.exe'.  (Bug #32197)

   * *Incompatible Change*: Multiple-table *Note `DELETE': delete.
     statements containing ambiguous aliases could have unintended side
     effects such as deleting rows from the wrong table. Example:

          DELETE FROM t1 AS a2 USING t1 AS a1 INNER JOIN t2 AS a2;

     This bug fix enables aliases to be declared only in the
     TABLE_REFERENCES part. Elsewhere in the statement, alias
     references are permitted but not alias declarations. However, this
     patch was reverted in MySQL 5.0.54 because it changed the behavior
     of a General Availability MySQL release.  (Bug #30234) See also
     Bug #27525.

   * *Incompatible Change*: Failure to consider collation when
     comparing space characters could result in incorrect index entry
     order, leading to incorrect comparisons, inability to find some
     index values, misordered index entries, misordered `ORDER BY'
     results, or tables that *Note `CHECK TABLE': check-table. reports
     as having corrupt indexes.

     As a result of this bug fix, indexes must be rebuilt for columns
     that use any of these character sets: `eucjpms', `euc_kr',
     `gb2312', `latin7', `macce', `ujis'. See *Note
     checking-table-incompatibilities::.  (Bug #29461)

   * *MySQL Cluster*: *Packaging*: Some commercial MySQL Cluster RPM
     packages included support for the `InnoDB' storage engine.
     (`InnoDB' is not part of the standard commercial MySQL Cluster
     offering.)  (Bug #31989)

   * *MySQL Cluster*: Attempting to restore a backup made on a cluster
     host using one endian to a machine using the other endian could
     cause the cluster to fail.  (Bug #29674)

   * *MySQL Cluster*: When restarting a data node, queries could hang
     during that node's start phase 5, and continue only after the node
     had entered phase 6.  (Bug #29364)

   * *MySQL Cluster*: Replica redo logs were inconsistently handled
     during a system restart.  (Bug #29354)

   * *MySQL Cluster*: Reads on *Note `BLOB': blob. columns were not
     locked when they needed to be to guarantee consistency.  (Bug
     #29102) See also Bug #31482.

   * *MySQL Cluster*: A query using joins between several large tables
     and requiring unique index lookups failed to complete, eventually
     returning `Uknown Error' after a very long period of time. This
     occurred due to inadequate handling of instances where the
     Transaction Coordinator ran out of `TransactionBufferMemory', when
     the cluster should have returned NDB error code 4012 (`Request
     ndbd time-out').  (Bug #28804)

   * *MySQL Cluster*: The description of the `--print' option provided
     in the output from *Note `ndb_restore `--help' ':
     mysql-cluster-programs-ndb-restore. was incorrect.  (Bug #27683)

   * *MySQL Cluster*: The management client's response to `START BACKUP
     WAIT COMPLETED' did not include the backup ID.  (Bug #27640)

   * *MySQL Cluster*: An invalid subselect on an *Note `NDB':
     mysql-cluster.  table could cause *Note `mysqld': mysqld. to crash.
     (Bug #27494)

   * *MySQL Cluster*: An attempt to perform a `SELECT ... FROM
     INFORMATION_SCHEMA.TABLES' whose result included information about
     *Note `NDB': mysql-cluster. tables for which the user had no
     privileges crashed the MySQL Server on which the query was
     performed.  (Bug #26793)

   * *MySQL Cluster*: Warnings and errors generated by *Note
     `ndb_config `--config-file=FILE'':
     mysql-cluster-programs-ndb-config.  were sent to `stdout', rather
     than to `stderr'.  (Bug #25941)

   * *MySQL Cluster*: Large file support did not work in AIX server
     binaries.  (Bug #10776)

   * *Replication*: The thread ID was not reset properly after
     execution of *Note `mysql_change_user()': mysql-change-user, which
     could cause replication failure when replicating temporary tables.
     (Bug #29734)

   * *Replication*: Operations that used the time zone replicated the
     time zone only for successful operations, but did not replicate
     the time zone for errors that need to know it.  (Bug #29536)

   * *Replication*: *Note `INSERT DELAYED': insert-delayed. statements
     on a master server are replicated as non-`DELAYED' inserts on
     slaves (which is normal, to preserve serialization), but the
     inserts on the slave did not use concurrent inserts. Now *Note
     `INSERT DELAYED': insert-delayed. on a slave is converted to a
     concurrent insert when possible, and to a normal insert otherwise.
     (Bug #29152)

   * *Replication*: *Note `DROP USER': drop-user. statements that named
     multiple users, only some of which could be dropped, were
     replicated incorrectly.  (Bug #29030)

   * *Replication*: An error that happened inside *Note `INSERT':
     insert, *Note `UPDATE': update, or *Note `DELETE': delete.
     statements performed from within a stored function or trigger
     could cause inconsistency between master and slave servers.  (Bug
     #27417)

   * *Replication*: Slave servers could incorrectly interpret an
     out-of-memory error from the master and reconnect using the wrong
     binary log position.  (Bug #24192)

   * When a *Note `TIMESTAMP': datetime. with a nonzero time part was
     converted to a *Note `DATE': datetime.  value, no warning was
     generated. This caused index lookups to assume that this is a
     valid conversion and was returning rows that match a comparison
     between a *Note `TIMESTAMP': datetime. value and a *Note `DATE':
     datetime. keypart. Now a warning is generated so that *Note
     `TIMESTAMP': datetime. with a nonzero time part will not match
     *Note `DATE': datetime. values.  (Bug #31221)

   * A server crash could occur when a non-`DETERMINISTIC' stored
     function was used in a `GROUP BY' clause.  (Bug #31035)

   * For an `InnoDB' table if a *Note `SELECT': select. was ordered by
     the primary key and also had a `WHERE field = value' clause on a
     different field that was indexed, a `DESC' order instruction would
     be ignored.  (Bug #31001)

   * A failed `HANDLER ... READ' operation could leave the table in a
     locked state.  (Bug #30632)

   * The optimization that uses a unique index to remove `GROUP BY' did
     not ensure that the index was actually used, thus violating the
     `ORDER BY' that is implied by `GROUP BY'.  (Bug #30596)

   * `SHOW STATUS LIKE 'Ssl_cipher_list'' from a MySQL client connected
     using SSL returned an empty string rather than a list of available
     ciphers.  (Bug #30593)

   * Memory corruption occurred for some queries with a top-level `OR'
     operation in the `WHERE' condition if they contained equality
     predicates and other sargable predicates in disjunctive parts of
     the condition.  (Bug #30396)

   * Issuing a *Note `DELETE': delete. statement having both an `ORDER
     BY' clause and a `LIMIT' clause could cause *Note `mysqld':
     mysqld. to crash.  (Bug #30385)

   * The `Last_query_cost' status variable value can be computed
     accurately only for simple `flat' queries, not complex queries
     such as those with subqueries or *Note `UNION': union.  However,
     the value was not consistently being set to 0 for complex queries.
     (Bug #30377)

   * Queries that had a `GROUP BY' clause and selected `COUNT(DISTINCT
     BIT_COLUMN)' returned incorrect results.  (Bug #30324)

   * The server created temporary tables for filesort operations in the
     working directory, not in the directory specified by the `tmpdir'
     system variable.  (Bug #30287)

   * The query cache does not support retrieval of statements for which
     column level access control applies, but the server was still
     caching such statements, thus wasting memory.  (Bug #30269)

   * Using `DISTINCT' or `GROUP BY' on a *Note `BIT': numeric-types.
     column in a *Note `SELECT': select. statement caused the column to
     be cast internally as an integer, with incorrect results being
     returned from the query.  (Bug #30245)

   * `GROUP BY' on *Note `BIT': numeric-types. columns produced
     incorrect results.  (Bug #30219)

   * Using *Note `KILL QUERY': kill.  or *Note `KILL CONNECTION': kill.
     to kill a *Note `SELECT': select. statement caused a server crash
     if the query cache was enabled.  (Bug #30201)

   * Prepared statements containing `CONNECTION_ID()' could be written
     improperly to the binary log.  (Bug #30200)

   * When a thread executing a *Note `DROP TABLE': drop-table.
     statement was killed, the table name locks that had been acquired
     were not released.  (Bug #30193)

   * Short-format *Note `mysql': mysql. commands embedded within `/*!
     ... */' comments were parsed incorrectly by *Note `mysql': mysql,
     which discarded the rest of the comment including the terminating
     `*/' characters. The result was a malformed (unclosed) comment. Now
     *Note `mysql': mysql. does not discard the `*/' characters.  (Bug
     #30164)

   * When *Note `mysqldump': mysqldump. wrote *Note `DROP DATABASE':
     drop-database. statements within version-specific comments, it
     included the terminating semicolon in the wrong place, causing
     following statements to fail when the dump file was reloaded.
     (Bug #30126)

   * Use of local variables with non-ASCII names in stored procedures
     crashed the server.  (Bug #30120)

   * On Windows, client libraries lacked symbols required for linking.
     (Bug #30118)

   * `--myisam-recover=''' (empty option value) did not disable
     `MyISAM' recovery.  (Bug #30088)

   * The `IS_UPDATABLE' column in the *Note `INFORMATION_SCHEMA.VIEWS':
     views-table. table was not always set correctly.  (Bug #30020)

   * Statements within stored procedures ignored the value of the
     `low_priority_updates' system variable.  (Bug #29963) See also Bug
     #26162.

   * For `MyISAM' tables on Windows, *Note `INSERT': insert, *Note
     `DELETE': delete, or *Note `UPDATE': update. followed by *Note
     `ALTER TABLE': alter-table. within *Note `LOCK TABLES':
     lock-tables. could cause table corruption.  (Bug #29957)

   * With auto-reconnect enabled, row fetching for a prepared statement
     could crash after reconnect occurred because loss of the statement
     handler was not accounted for.  (Bug #29948)

   * *Note `LOCK TABLES': lock-tables. did not pre-lock tables used in
     triggers of the locked tables. Unexpected locking behavior and
     statement failures similar to `failed: 1100: Table 'XX' was not
     locked with LOCK TABLES' could result.  (Bug #29929)

   * `INSERT ... VALUES(CONNECTION_ID(), ...)' statements were written
     to the binary log in such a way that they could not be properly
     restored.  (Bug #29928)

   * Adding `DISTINCT' could cause incorrect rows to appear in a query
     result.  (Bug #29911)

   * Using the `DATE()' function in a `WHERE' clause did not return any
     records after encountering `NULL'. However, using `TRIM()' or
     `CAST()' produced the correct results.  (Bug #29898)

   * Very long prepared statements in stored procedures could cause a
     server crash.  (Bug #29856)

   * If query execution involved a temporary table, `GROUP_CONCAT()'
     could return a result with an incorrect character set.  (Bug
     #29850)

   * If one thread was performing concurrent inserts, other threads
     reading from the same table using equality key searches could see
     the index values for new rows before the data values had been
     written, leading to reports of table corruption.  (Bug #29838)

   * Repeatedly accessing a view in a stored procedure (for example, in
     a loop) caused a small amount of memory to be allocated per
     access. Although this memory is deallocated on disconnect, it
     could be a problem for a long running stored procedures that make
     repeated access of views.  (Bug #29834)

   * *Note `mysqldump': mysqldump. produced output that incorrectly
     discarded the `NO_AUTO_VALUE_ON_ZERO' value of the `sql_mode'
     variable after dumping triggers.  (Bug #29788)

   * For `MEMORY' tables, the `index_merge' union access method could
     return incorrect results.  (Bug #29740)

   * Comparison of *Note `TIME': time. values using the `BETWEEN'
     operator led to string comparison, producing incorrect results in
     some cases. Now the values are compared as integers.  (Bug #29739)

   * For a table with a *Note `DATE': datetime. column DATE_COL such
     that selecting rows with `WHERE DATE_COL = 'DATE_VAL 00:00:00''
     yielded a nonempty result, adding `GROUP BY DATE_COL' caused the
     result to be empty.  (Bug #29729)

   * In some cases, `INSERT INTO ... SELECT ... GROUP BY' could insert
     rows even if the *Note `SELECT': select. by itself produced an
     empty result.  (Bug #29717)

   * For the embedded server, the *Note `mysql_stmt_store_result()':
     mysql-stmt-store-result. C API function caused a memory leak for
     empty result sets.  (Bug #29687)

   * *Note `EXPLAIN': explain. produced `Impossible where' for
     statements of the form `SELECT ... FROM t WHERE c=0', where `c'
     was an *Note `ENUM': enum.  column defined as a primary key.  (Bug
     #29661)

   * On Windows, *Note `ALTER TABLE': alter-table. hung if records were
     locked in share mode by a long-running transaction.  (Bug #29644)

   * A left join between two views could produce incorrect results.
     (Bug #29604)

   * Certain statements with unions, subqueries, and joins could result
     in huge memory consumption.  (Bug #29582)

   * Clients using SSL could hang the server.  (Bug #29579)

   * A slave running with `--log-slave-updates' would fail to write
     `INSERT DELAY IGNORE' statements to its binary log, resulting in
     different binary log contents on the master and slave.  (Bug
     #29571)

   * An incorrect result was returned when comparing string values that
     were converted to *Note `TIME': time.  values with `CAST()'.  (Bug
     #29555)

   * `gcov' coverage-testing information was not written if the server
     crashed.  (Bug #29543)

   * In the `ascii' character set, conversion of DEL (`0x7F') to
     Unicode incorrectly resulted in QUESTION MARK (`0x3F') rather than
     DEL.  (Bug #29499)

   * A field packet with `NULL' fields caused a `libmysqlclient' crash.
     (Bug #29494)

   * When using a combination of `HANDLER... READ' and *Note `DELETE':
     delete. on a table, MySQL continued to open new copies of the
     table every time, leading to an exhaustion of file descriptors.
     (Bug #29474) This regression was introduced by Bug #21587.

   * On Windows, the *Note `mysql': mysql. client died if the user
     entered a statement and Return after entering `Control+C'.  (Bug
     #29469)

   * Corrupt data resulted from use of `SELECT ... INTO OUTFILE
     'FILE_NAME' FIELDS ENCLOSED BY 'C'', where C is a digit or minus
     sign, followed by `LOAD DATA INFILE 'FILE_NAME' FIELDS ENCLOSED BY
     'C''.  (Bug #29442)

   * Killing an *Note `INSERT DELAYED': insert-delayed. thread caused a
     server crash.  (Bug #29431)

   * Use of *Note `SHOW BINLOG EVENTS': show-binlog-events. for a
     nonexistent log file followed by *Note `PURGE BINARY LOGS':
     purge-binary-logs. caused a server crash.  (Bug #29420)

   * Assertion failure could occur for grouping queries that employed
     *Note `DECIMAL': numeric-types. user variables with assignments to
     them.  (Bug #29417)

   * For `CAST(EXPR AS DECIMAL(M,D))', the limits of 65 and 30 on the
     precision (M) and scale (D) were not enforced.  (Bug #29415)

   * If a view used a function in its *Note `SELECT': select.
     statement, the columns from the view were not inserted into the
     *Note `INFORMATION_SCHEMA.COLUMNS': columns-table. table.  (Bug
     #29408)

   * Results for a select query that aliases the column names against a
     view could duplicate one column while omitting another. This bug
     could occur for a query over a multiple-table view that includes
     an `ORDER BY' clause in its definition.  (Bug #29392)

   * *Note `mysqldump': mysqldump. created a stray file when a given a
     too-long file name argument.  (Bug #29361)

   * The special `zero' *Note `ENUM': enum. value was coerced to the
     normal empty string *Note `ENUM': enum. value during a
     column-to-column copy. This affected `CREATE ... SELECT'
     statements and *Note `SELECT': select. statements with aggregate
     functions on *Note `ENUM': enum. columns in the `GROUP BY' clause.
     (Bug #29360)

   * Optimization of queries with `DETERMINISTIC' stored functions in
     the `WHERE' clause was ineffective: A sequential scan was always
     used.  (Bug #29338)

   * `MyISAM' corruption could occur with the `cp932_japanese_ci'
     collation for the `cp932' character set due to incorrect
     comparison for trailing space.  (Bug #29333)

   * The *Note `mysql_list_fields()': mysql-list-fields. C API function
     incorrectly set `MYSQL_FIELD::decimals' for some view columns.
     (Bug #29306)

   * `FULLTEXT' indexes could be corrupted by certain `gbk' characters.
     (Bug #29299)

   * *Note `SELECT ... INTO OUTFILE': select. followed by *Note `LOAD
     DATA': load-data. could result in garbled characters when the
     `FIELDS ENCLOSED BY' clause named a delimiter of `'0'', `'b'',
     `'n'', `'r'', `'t'', `'N'', or `'Z'' due to an interaction of
     character encoding and doubling for data values containing the
     enclosed-by character.  (Bug #29294)

   * Sort order of the collation wasn't used when comparing trailing
     spaces. This could lead to incorrect comparison results,
     incorrectly created indexes, or incorrect result set order for
     queries that include an `ORDER BY' clause.  (Bug #29261)

   * If an *Note `ENUM': enum. column contained `''' as one of its
     members (represented with numeric value greater than 0), and the
     column contained error values (represented as 0 and displayed as
     `'''), using *Note `ALTER TABLE': alter-table. to modify the
     column definition caused the 0 values to be given the numeric
     value of the nonzero `''' member.  (Bug #29251)

   * Calling *Note `mysql_options()': mysql-options. after *Note
     `mysql_real_connect()': mysql-real-connect. could cause clients to
     crash.  (Bug #29247)

   * *Note `CHECK TABLE': check-table. for `ARCHIVE' tables could
     falsely report table corruption or cause a server crash.  (Bug
     #29207)

   * Mixing binary and `utf8' columns in a union caused field lengths
     to be calculated incorrectly, resulting in truncation.  (Bug
     #29205)

   * `AsText()' could fail with a buffer overrun.  (Bug #29166)

   * `InnoDB' refused to start on some versions of FreeBSD with
     LinuxThreads. This is fixed by enabling file locking on FreeBSD.
     (Bug #29155)

   * *Note `LOCK TABLES': lock-tables. was not atomic when more than
     one `InnoDB' tables were locked.  (Bug #29154)

   * A network structure was initialized incorrectly, leading to
     embedded server crashes.  (Bug #29117)

   * An assertion failure occurred if a query contained a conjunctive
     predicate of the form ` VIEW_COLUMN = constant' in the `WHERE'
     clause and the `GROUP BY' clause contained a reference to a
     different view column. The fix also enables application of an
     optimization that was being skipped if a query contained a
     conjunctive predicate of the form `VIEW_COLUMN = constant' in the
     `WHERE' clause and the `GROUP BY' clause contained a reference to
     the same view column.  (Bug #29104)

   * A maximum of 4TB `InnoDB' free space was reported by `SHOW TABLE
     STATUS,' which is incorrect on systems with more than 4TB space.
     (Bug #29097)

   * If an *Note `INSERT INTO ... SELECT': insert-select. statement
     inserted into the same table that the *Note `SELECT': select.
     retrieved from, and the *Note `SELECT': select. included `ORDER
     BY' and `LIMIT' clauses, different data was inserted than the data
     produced by the *Note `SELECT': select. executed by itself.  (Bug
     #29095)

   * Queries that performed a lookup into a *Note `BINARY':
     binary-varbinary. index containing key values ending with spaces
     caused an assertion failure for debug builds and incorrect results
     for nondebug builds.  (Bug #29087)

   * The semantics of *Note `BIGINT': numeric-types. depended on
     platform-specific characteristics.  (Bug #29079)

   * A byte-order issue in writing a spatial index to disk caused bad
     index files on some systems.  (Bug #29070)

   * If one of the queries in a *Note `UNION': union.  used the
     `SQL_CACHE' option and another query in the *Note `UNION': union.
     contained a nondeterministic function, the result was still
     cached. For example, this query was incorrectly cached:

          SELECT NOW() FROM t1 UNION SELECT SQL_CACHE 1 FROM t1;

     (Bug #29053)

   * Creation of a legal stored procedure could fail if no default
     database had been selected.  (Bug #29050)

   * *Note `REPLACE': replace, *Note `INSERT IGNORE': insert, and
     `UPDATE IGNORE' did not work for `FEDERATED' tables.  (Bug #29019)

   * Inserting into `InnoDB' tables and executing *Note `RESET MASTER':
     reset-master. in multiple threads cause assertion failure in debug
     server binaries.  (Bug #28983)

   * For a `ucs2' column, `GROUP_CONCAT()' did not convert separators
     to the result character set before inserting them, producing a
     result containing a mixture of two different character sets.  (Bug
     #28925)

   * Queries using UDFs or stored functions were cached.  (Bug #28921)

   * For a join with `GROUP BY' or `ORDER BY' and a view reference in
     the `FROM' list, the query metadata erroneously showed empty table
     aliases and database names for the view columns.  (Bug #28898)

   * Coercion of ASCII values to character sets that are a superset of
     ASCII sometimes was not done, resulting in `illegal mix of
     collations' errors. These cases now are resolved using repertoire,
     a new string expression attribute (see *Note charset-repertoire::).
     (Bug #28875)

   * Non-`utf8' characters could get mangled when stored in `CSV'
     tables.  (Bug #28862)

   * *Note `ALTER VIEW': alter-view. is not supported as a prepared
     statement but was not being rejected.  *Note `ALTER VIEW':
     alter-view. is now prohibited as a prepared statement or when
     called within stored routines.  (Bug #28846)

   * In strict SQL mode, errors silently stopped the SQL thread even
     for errors named using the `--slave-skip-errors' option.  (Bug
     #28839)

   * Fast *Note `ALTER TABLE': alter-table. (that works without
     rebuilding the table) acquired duplicate locks in the storage
     engine. In `MyISAM', if *Note `ALTER TABLE': alter-table. was
     issued under *Note `LOCK TABLE': lock-tables, it caused all data
     inserted after *Note `LOCK TABLE': lock-tables. to disappear.
     (Bug #28838)

   * Killing an SSL connection on platforms where MySQL is compiled
     with `-DSIGNAL_WITH_VIO_CLOSE' (Windows, Mac OS X, and some
     others) could crash the server.  (Bug #28812)

   * Runtime changes to the `log_queries_not_using_indexes' system
     variable were ignored.  (Bug #28808)

   * Tables using the `InnoDB' storage engine incremented
     `AUTO_INCREMENT' values incorrectly with `ON DUPLICATE KEY UPDATE'.
     (Bug #28781)

   * Selecting a column not present in the selected-from table caused
     an extra error to be produced by *Note `SHOW ERRORS': show-errors.
     (Bug #28677)

   * For a statement of the form `CREATE t1 SELECT INTEGER_CONSTANT',
     the server created the column using the *Note `DECIMAL':
     numeric-types. data type for large negative values that are within
     the range of *Note `BIGINT': numeric-types.  (Bug #28625)

   * For `InnoDB' tables, MySQL unnecessarily sorted records in certain
     cases when the records were retrieved by `InnoDB' in the proper
     order already.  (Bug #28591)

   * A *Note `SELECT': select. in one connection could be blocked by
     *Note `INSERT ... ON DUPLICATE KEY UPDATE': insert-on-duplicate.
     in another connection even when `low_priority_updates' is set.
     (Bug #28587)

   * *Note `mysql_install_db': mysql-install-db. could fail to find
     script files that it needs.  (Bug #28585)

   * When one thread attempts to lock two (or more) tables and another
     thread executes a statement that aborts these locks (such as *Note
     `REPAIR TABLE': repair-table, *Note `OPTIMIZE TABLE':
     optimize-table, or *Note `CHECK TABLE': check-table.), the thread
     might get a table object with an incorrect lock type in the table
     cache. The result is table corruption or a server crash.  (Bug
     #28574)

   * *Note `mysql_upgrade': mysql-upgrade. could run binaries
     dynamically linked against incorrect versions of shared libraries.
     (Bug #28560)

   * If a stored procedure was created and invoked prior to selecting a
     default database with *Note `USE': use, a `No database selected'
     error occurred.  (Bug #28551)

   * On Mac OS X, shared-library installation path names were incorrect.
     (Bug #28544)

   * Using the `--skip-add-drop-table 'option with *Note `mysqldump':
     mysqldump. generated incorrect SQL if the database included any
     views. The recreation of views requires the creation and removal
     of temporary tables.  This option suppressed the removal of those
     temporary tables.  The same applied to `--compact' since this
     option also invokes `--skip-add-drop-table'.  (Bug #28524)

   * *Note `mysqlbinlog --hexdump': mysqlbinlog. generated incorrect
     output due to omission of the ``#'' comment character for some
     comment lines.  (Bug #28293)

   * A race condition in the interaction between `MyISAM' and the query
     cache code caused the query cache not to invalidate itself for
     concurrently inserted data.  (Bug #28249)

   * Indexing column prefixes in `InnoDB' tables could cause table
     corruption.  (Bug #28138)

   * Index creation could fail due to truncation of key values to the
     maximum key length rather than to a mulitiple of the maximum
     character length.  (Bug #28125)

   * The `LOCATE()' function returned `NULL' if any of its arguments
     evaluated to `NULL'. Likewise, the predicate, `LOCATE(STR,NULL) IS
     NULL', erroneously evaluated to `FALSE'.  (Bug #27932)

   * On Windows, symbols for yaSSL and taocrypt were missing from
     `mysqlclient.lib', resulting in unresolved symbol errors for
     clients linked against that library.  (Bug #27861)

   * *Note `SHOW COLUMNS': show-columns. returned `NULL' instead of the
     empty string for the `Default' value of columns that had no default
     specified.  (Bug #27747)

   * The modification of a table by a partially completed multi-column
     update was not recorded in the binlog, rather than being marked by
     an event and a corresponding error code.  (Bug #27716)

   * With recent versions of DBD::mysql, *Note `mysqlhotcopy':
     mysqlhotcopy. generated table names that were doubly qualified
     with the database name.  (Bug #27694)

   * The anonymous accounts were not being created during MySQL
     installation.  (Bug #27692)

   * Some *Note `SHOW': show. statements and `INFORMATION_SCHEMA'
     queries could expose information not permitted by the user's
     access privileges. An implication of this change is that *Note
     `SHOW TRIGGERS': show-triggers. and the *Note
     `INFORMATION_SCHEMA.TRIGGERS': triggers-table. table require the
     `TRIGGER'
     (http://dev.mysql.com/doc/refman/5.1/en/privileges-provided.html#priv_trigger)
     privilege, not `SUPER'.  (Bug #27629)

   * A stack overrun could occur when storing *Note `DATETIME':
     datetime. values using repeated prepared statements.  (Bug #27592)

   * Dropping a user-defined function could cause a server crash if the
     function was still in use by another thread.  (Bug #27564)

   * Some character mappings in the `ascii.xml' file were incorrect.

     As a result of this bug fix, indexes must be rebuilt for columns
     that use the `ascii_general_ci' collation for columns that contain
     any of these characters: `'`'', `'['', `'\'', `']'', `'~''. See
     *Note checking-table-incompatibilities::.  (Bug #27562)

   * The parser rules for the *Note `SHOW PROFILE': show-profile.
     statement were revised to work with older versions of `bison'.
     (Bug #27433)

   * Unsafe aliasing in the source caused a client library crash when
     compiled with `gcc' 4 at high optimization levels.  (Bug #27383)

   * A *Note `SELECT': select. with more than 31 nested dependent
     subqueries returned an incorrect result.  (Bug #27352)

   * Index-based range reads could fail for comparisons that involved
     contraction characters (such as `ch' in Czech or `ll' in Spanish).
     (Bug #27345)

   * Aggregations in subqueries that refer to outer query columns were
     not always correctly referenced to the proper outer query.  (Bug
     #27333)

   * *Note `INSERT INTO ... SELECT': insert-select. caused a crash if
     `innodb_locks_unsafe_for_binlog' was enabled.  (Bug #27294)

   * Error returns from the `time()' system call were ignored.  (Bug
     #27198)

   * Phantom reads could occur under `InnoDB' `SERIALIZABLE' isolation
     level.  (Bug #27197)

   * The `SUBSTRING()' function returned the entire string instead of
     an empty string when it was called from a stored procedure and
     when the length parameter was specified by a variable with the
     value ``0''.  (Bug #27130)

   * `ALTER TABLE ... ENABLE KEYS' could cause *Note `mysqld': mysqld.
     to crash when executed on a table containing on a `MyISAM' table
     containing billions of rows.  (Bug #27029)

   * `FEDERATED' tables had an artificially low maximum of key length.
     (Bug #26909)

   * Binary content `0x00' in a *Note `BLOB': blob. column sometimes
     became `0x5C 0x00' following a dump and reload, which could cause
     problems with data using multi-byte character sets such as `GBK'
     (Chinese). This was due to a problem with `SELECT INTO OUTFILE'
     whereby *Note `LOAD DATA': load-data. later incorrectly
     interpreted `0x5C' as the second byte of a multi-byte sequence
     rather than as the `SOLIDUS' (`\') character, used by MySQL as the
     escape character.  (Bug #26711)

   * Index creation could corrupt the table definition in the `.frm'
     file: 1) A table with the maximum number of key segments and
     maximum length key name would have a corrupted `.frm' file, due to
     incorrect calculation of the total key length. 2) `MyISAM' would
     reject a table with the maximum number of keys and the maximum
     number of key segments in all keys. (It would permit one less than
     this total maximum.) Now `MyISAM' accepts a table defined with the
     maximum.  (Bug #26642)

   * After the first read of a `TEMPORARY' table, *Note `CHECK TABLE':
     check-table. could report the table as being corrupt.  (Bug #26325)

   * If an operation had an `InnoDB' table, and two triggers, `AFTER
     UPDATE' and `AFTER INSERT', competing for different resources
     (such as two distinct `MyISAM' tables), the triggers were unable
     to execute concurrently. In addition, *Note `INSERT': insert. and
     *Note `UPDATE': update. statements for the `InnoDB' table were
     unable to run concurrently.  (Bug #26141)

   * *Note `ALTER DATABASE': alter-database. did not require at least
     one option.  (Bug #25859)

   * Using *Note `HANDLER': handler. to open a table having a storage
     engine not supported by *Note `HANDLER': handler. properly
     returned an error, but also improperly prevented the table from
     being dropped by other connections.  (Bug #25856)

   * The index merge union access algorithm could produce incorrect
     results with `InnoDB' tables. The problem could also occur for
     queries that used `DISTINCT'.  (Bug #25798)

   * When using a `FEDERATED' table, the value of `LAST_INSERT_ID()'
     would not correctly update the C API interface, which would affect
     the autogenerated ID returned both through the C API and the MySQL
     protocol, affecting Connectors that used the protocol or C API.
     (Bug #25714)

   * The server was blocked from opening other tables while the
     `FEDERATED' engine was attempting to open a remote table. Now the
     server does not check the correctness of a `FEDERATED' table at
     *Note `CREATE TABLE': create-table. time, but waits until the
     table actually is accessed.  (Bug #25679)

   * Under ActiveState Perl, `mysql-test-run.pl' could kill itself when
     attempting to kill other processes.  (Bug #25657)

   * Several `InnoDB' assertion failures were corrected.  (Bug #25645)

   * A query with `DISTINCT' in the select list to which the loose-scan
     optimization for grouping queries was applied returned an
     incorrect result set when the query was used with the
     `SQL_BIG_RESULT' option.  (Bug #25602)

   * For a multiple-row insert into a `FEDERATED' table that refers to
     a remote transactional table, if the insert failed for a row due
     to constraint failure, the remote table would contain a partial
     commit (the rows preceding the failed one) instead of rolling back
     the statement completely. This occurred because the rows were
     treated as individual inserts.

     Now `FEDERATED' performs bulk-insert handling such that multiple
     rows are sent to the remote table in a batch.  This provides a
     performance improvement and enables the remote table to perform
     statement rollback properly should an error occur. This capability
     has the following limitations:

        * The size of the insert cannot exceed the maximum packet size
          between servers. If the insert exceeds this size, it is
          broken into multiple packets and the rollback problem can
          occur.

        * Bulk-insert handling does not occur for *Note `INSERT ... ON
          DUPLICATE KEY UPDATE': insert-on-duplicate.

     (Bug #25513)

   * The `FEDERATED' storage engine failed silently for *Note `INSERT
     ... ON DUPLICATE KEY UPDATE': insert-on-duplicate. if a duplicate
     key violation occurred. `FEDERATED' does not support `ON DUPLICATE
     KEY UPDATE', so now it correctly returns an `ER_DUP_KEY' error if
     a duplicate key violation occurs.  (Bug #25511)

   * For `InnoDB' tables, *Note `CREATE TABLE a AS SELECT * FROM A':
     create-table-select. would fail.  (Bug #25164)

   * In a stored function or trigger, when `InnoDB' detected deadlock,
     it attempted rollback and displayed an incorrect error message
     (`Explicit or implicit commit is not permitted in stored function
     or trigger'). Now `InnoDB' returns an error under these conditions
     and does not attempt rollback. Rollback is handled outside of
     `InnoDB' above the function/trigger level.  (Bug #24989)

   * A too-long `shared-memory-base-name' value could cause a buffer
     overflow and crash the server or clients.  (Bug #24924)

   * Dropping a temporary `InnoDB' table that had been locked with
     *Note `LOCK TABLES': lock-tables.  caused a server crash.  (Bug
     #24918)

   * On Windows, executables did not include Vista manifests.  (Bug
     #24732) See also Bug #22563.

   * If MySQL/`InnoDB' crashed very quickly after starting up, it would
     not force a checkpoint. In this case, `InnoDB' would skip crash
     recovery at next startup, and the database would become corrupt.
     Now, if the redo log scan at `InnoDB' startup goes past the last
     checkpoint, crash recovery is forced.  (Bug #23710)

   * The server deducted some bytes from the `key_cache_block_size'
     option value and reduced it to the next lower 512 byte boundary.
     The resulting block size was not a power of two. Setting the
     `key_cache_block_size' system variable to a value that is not a
     power of two resulted in `MyISAM' table corruption.  (Bug #23068,
     Bug #28478, Bug #25853)

   * *Note `SHOW INNODB STATUS': show-innodb-status. caused an
     assertion failure under high load.  (Bug #22819)

   * *Note `SHOW BINLOG EVENTS': show-binlog-events. displayed
     incorrect values of `End_log_pos' for events associated with
     transactional storage engines.  (Bug #22540)

   * A statement of the form *Note `CREATE TABLE IF NOT EXISTS t1
     SELECT f1() AS i': create-table-select. failed with a deadlock
     error if the stored function `f1()' referred to a table with the
     same name as the to-be-created table. Now it correctly produces a
     message that the table already exists.  (Bug #22427)

   * Read lock requests that were blocked by a pending write lock
     request were not permitted to proceed if the statement requesting
     the write lock was killed.  (Bug #21281)

   * Under heavy load with a large query cache, invalidating part of
     the cache could cause the server to freeze (that is, to be unable
     to service other operations until the invalidation was complete).
     (Bug #21074) See also Bug #39253.

   * `mysql-stress-test.pl' and `mysqld_multi.server.sh' were missing
     from some binary distributions.  (Bug #21023, Bug #25486)

   * On Windows, the server used 10MB of memory for each connection
     thread, resulting in memory exhaustion. Now each thread uses 1MB.
     (Bug #20815)

   * Worked around an `icc' problem with an incorrect machine
     instruction being generated in the context of software
     pre-fetching after a subroutine got in-lined.  (Upgrading to `icc'
     10.0.026 makes the workaround unnecessary.)  (Bug #20803)

   * `InnoDB' produced an unnecessary (and harmless) warning:
     ``InnoDB': Error: trying to declare trx to enter `InnoDB', but
     `InnoDB': it already is declared'.  (Bug #20090)

   * Under ActiveState Perl, `mysql-test-run.pl' would not run.  (Bug
     #18415)

   * The server crashed when the size of an `ARCHIVE' table grew larger
     than 2GB.  (Bug #15787)

   * `SQL_BIG_RESULT' had no effect for *Note `CREATE TABLE ... SELECT
     SQL_BIG_RESULT ...': create-table-select. statements.  (Bug #15130)

   * On 64-bit Windows systems, the Config Wizard failed to complete
     the setup because 64-bit Windows does not resolve dynamic linking
     of the 64-bit `libmysql.dll' to a 32-bit application like the
     Config Wizard.  (Bug #14649)

   * *Note `mysql_setpermission': mysql-setpermission. tried to grant
     global-only privileges at the database level.  (Bug #14618)

   * Parameters of type *Note `DATETIME': datetime. or *Note `DATE':
     datetime. in stored procedures were silently converted to *Note
     `VARBINARY': binary-varbinary.  (Bug #13675)

   * For the general query log, logging of prepared statements executed
     using the C API differed from logging of prepared statements
     performed with *Note `PREPARE': prepare.  and *Note `EXECUTE':
     execute. Logging for the latter was missing the `Prepare' and
     `Execute' lines.  (Bug #13326)

   * The server returned data from *Note `SHOW CREATE TABLE':
     show-create-table. statement or a *Note `SELECT': select.
     statement on an `INFORMATION_SCHEMA' table using the `binary'
     character set.  (Bug #10491)

   * Backup software can cause `ERROR_SHARING_VIOLATION' or
     `ERROR_LOCK_VIOLATION' conditions during file operations. `InnoDB'
     now retries forever until the condition goes away.  (Bug #9709)


File: manual.info,  Node: news-5-0-50sp1a,  Next: news-5-0-50sp1,  Prev: news-5-0-51,  Up: news-5-0-x

D.1.47 Changes in MySQL Enterprise 5.0.50sp1a [QSP] (11 January 2008)
---------------------------------------------------------------------

This is a _Service Pack_ release of the MySQL Enterprise Server 5.0.

This is a bugfix release that replaces MySQL 5.0.50sp1.

*Bugs Fixed*

   * *Security Fix*: Three vulnerabilities in yaSSL versions 1.7.5 and
     earlier were discovered that could lead to a server crash or
     execution of unauthorized code. The exploit requires a server with
     yaSSL enabled and TCP/IP connections enabled, but does not require
     valid MySQL account credentials. The exploit does not apply to
     OpenSSL.

     *Warning*:

     The proof-of-concept exploit is freely available on the Internet.
     Everyone with a vulnerable MySQL configuration is advised to
     upgrade _immediately_.

     (Bug #33814, CVE-2008-0226, CVE-2008-0227)


File: manual.info,  Node: news-5-0-50sp1,  Next: news-5-0-50,  Prev: news-5-0-50sp1a,  Up: news-5-0-x

D.1.48 Changes in MySQL Enterprise 5.0.50sp1 [QSP] (12 December 2007)
---------------------------------------------------------------------

This is a _Service Pack_ release of the MySQL Enterprise Server 5.0.

This section documents all changes and bugfixes that have been applied
since the last MySQL Enterprise Server release (5.0.50).  If you would
like to receive more fine-grained and personalized _update alerts_
about fixes that are relevant to the version and features you use,
please consider subscribing to _MySQL Enterprise_ (a commercial MySQL
offering). For more details please see
http://www.mysql.com/products/enterprise/advisors.html.

*Bugs Fixed*

   * *Performance*: `InnoDB' had a race condition for an adaptive hash
     rw-lock waiting for an X-lock. This fix may also provide
     significant speed improvements on systems experiencing problems
     with contention for the adaptive hash index.  (Bug #29560)

   * *Security Fix*: Using *Note `RENAME TABLE': rename-table. against a
     table with explicit `DATA DIRECTORY' and `INDEX DIRECTORY' options
     can be used to overwrite system table information by replacing the
     symbolic link points. the file to which the symlink points.

     MySQL will now return an error when the file to which the symlink
     points already exists.  (Bug #32111, CVE-2007-5969)

   * *Security Fix*: *Note `ALTER VIEW': alter-view. retained the
     original `DEFINER' value, even when altered by another user, which
     could enable that user to gain the access rights of the view. Now
     *Note `ALTER VIEW': alter-view. is permitted only to the original
     definer or users with the `SUPER' privilege.  (Bug #29908)

   * *Security Fix*: When using a `FEDERATED' table, the local server
     could be forced to crash if the remote server returned a result
     with fewer columns than expected.  (Bug #29801)

   * A build problem introduced in MySQL 5.0.52 was resolved: The x86
     32-bit Intel `icc'-compiled server binary had unwanted dependences
     on Intel `icc' runtime libraries.  (Bug #32514)

   * `InnoDB' does not support `SPATIAL' indexes, but could crash when
     asked to handle one. Now an error is returned.  (Bug #32125)

   * `mysql-test-run.pl' could not run *Note `mysqld': mysqld. with
     `root' privileges.  (Bug #30630)


File: manual.info,  Node: news-5-0-50,  Next: news-5-0-48,  Prev: news-5-0-50sp1,  Up: news-5-0-x

D.1.49 Changes in MySQL Enterprise 5.0.50 [MRU] (19 October 2007)
-----------------------------------------------------------------

This is a _Monthly Rapid Update_ release of the MySQL Enterprise Server
5.0.

This section documents all changes and bugfixes that have been applied
since the last MySQL Enterprise Server release (5.0.48).  If you would
like to receive more fine-grained and personalized _update alerts_
about fixes that are relevant to the version and features you use,
please consider subscribing to _MySQL Enterprise_ (a commercial MySQL
offering). For more details please see
http://www.mysql.com/products/enterprise/advisors.html.

*Functionality Added or Changed*

   * *Incompatible Change*: The parser accepted statements that
     contained `/* ...  */' that were not properly closed with `*/',
     such as `SELECT 1 /* + 2'. Statements that contain unclosed
     `/*'-comments now are rejected with a syntax error.

     This fix has the potential to cause incompatibilities. Because of
     Bug #26302, which caused the trailing `*/' to be truncated from
     comments in views, stored routines, triggers, and events, it is
     possible that objects of those types may have been stored with
     definitions that now will be rejected as syntactically invalid.
     Such objects should be dropped and re-created so that their
     definitions do not contain truncated comments. If a stored object
     definition contains only a single statement (does not use a *Note
     `BEGIN ... END': begin-end. block) and contains a comment within
     the statement, the comment should be moved to follow the statement
     or the object should be rewritten to use a *Note `BEGIN ... END':
     begin-end. block. For example, this statement:

          CREATE PROCEDURE p() SELECT 1 /* my comment */ ;

     Can be rewritten in either of these ways:

          CREATE PROCEDURE p() SELECT 1; /* my comment */
          CREATE PROCEDURE p() BEGIN SELECT 1 /* my comment */ ; END;

     (Bug #28779)

   * *MySQL Cluster*: Mapping of *Note `NDB': mysql-cluster. error
     codes to MySQL storage engine error codes has been improved.  (Bug
     #28423)

   * *MySQL Cluster*: The output from the cluster management client
     showing the progress of data node starts has been improved.  (Bug
     #23354)

   * Server parser performance was improved for expression parsing by
     lowering the number of state transitions and reductions needed.
     (Bug #30625)

   * Server parser performance was improved for boolean expressions.
     (Bug #30237)

*Bugs Fixed*

   * *Incompatible Change*: The file `mysqld.exe' was mistakenly
     included in binary distributions between MySQL 5.0.42 and 5.0.48.
     You should use `mysqld-nt.exe'.  (Bug #32197)

   * *Incompatible Change*: Multiple-table *Note `DELETE': delete.
     statements containing ambiguous aliases could have unintended side
     effects such as deleting rows from the wrong table. Example:

          DELETE FROM t1 AS a2 USING t1 AS a1 INNER JOIN t2 AS a2;

     This fix enables aliases to be declared only in the
     TABLE_REFERENCES part. Elsewhere in the statement, alias
     references are permitted but not alias declarations. However, this
     patch was reverted in MySQL 5.0.54 because it changed the behavior
     of a General Availability MySQL release.  (Bug #30234) See also
     Bug #27525.

   * *MySQL Cluster*: *Packaging*: Some commercial MySQL Cluster RPM
     packages included support for the `InnoDB' storage engine.
     (`InnoDB' is not part of the standard commercial MySQL Cluster
     offering.)  (Bug #31989)

   * *MySQL Cluster*: Attempting to restore a backup made on a cluster
     host using one endian to a machine using the other endian could
     cause the cluster to fail.  (Bug #29674)

   * *MySQL Cluster*: Reads on *Note `BLOB': blob. columns were not
     locked when they needed to be to guarantee consistency.  (Bug
     #29102) See also Bug #31482.

   * *MySQL Cluster*: A query using joins between several large tables
     and requiring unique index lookups failed to complete, eventually
     returning `Uknown Error' after a very long period of time. This
     occurred due to inadequate handling of instances where the
     Transaction Coordinator ran out of `TransactionBufferMemory', when
     the cluster should have returned NDB error code 4012 (`Request
     ndbd time-out').  (Bug #28804)

   * *MySQL Cluster*: The description of the `--print' option provided
     in the output from *Note `ndb_restore `--help' ':
     mysql-cluster-programs-ndb-restore. was incorrect.  (Bug #27683)

   * *MySQL Cluster*: An invalid subselect on an *Note `NDB':
     mysql-cluster.  table could cause *Note `mysqld': mysqld. to crash.
     (Bug #27494)

   * *MySQL Cluster*: An attempt to perform a `SELECT ... FROM
     INFORMATION_SCHEMA.TABLES' whose result included information about
     *Note `NDB': mysql-cluster. tables for which the user had no
     privileges crashed the MySQL Server on which the query was
     performed.  (Bug #26793)

   * When a *Note `TIMESTAMP': datetime. with a nonzero time part was
     converted to a *Note `DATE': datetime.  value, no warning was
     generated. This caused index lookups to assume that this is a
     valid conversion and was returning rows that match a comparison
     between a *Note `TIMESTAMP': datetime. value and a *Note `DATE':
     datetime. keypart. Now a warning is generated so that *Note
     `TIMESTAMP': datetime. with a nonzero time part will not match
     *Note `DATE': datetime. values.  (Bug #31221)

   * A server crash could occur when a non-`DETERMINISTIC' stored
     function was used in a `GROUP BY' clause.  (Bug #31035)

   * For an `InnoDB' table if a *Note `SELECT': select. was ordered by
     the primary key and also had a `WHERE field = value' clause on a
     different field that was indexed, a `DESC' order instruction would
     be ignored.  (Bug #31001)

   * A failed `HANDLER ... READ' operation could leave the table in a
     locked state.  (Bug #30632)

   * The optimization that uses a unique index to remove `GROUP BY' did
     not ensure that the index was actually used, thus violating the
     `ORDER BY' that is implied by `GROUP BY'.  (Bug #30596)

   * `SHOW STATUS LIKE 'Ssl_cipher_list'' from a MySQL client connected
     using SSL returned an empty string rather than a list of available
     ciphers.  (Bug #30593)

   * Issuing a *Note `DELETE': delete. statement having both an `ORDER
     BY' clause and a `LIMIT' clause could cause *Note `mysqld':
     mysqld. to crash.  (Bug #30385)

   * The `Last_query_cost' status variable value can be computed
     accurately only for simple `flat' queries, not complex queries
     such as those with subqueries or *Note `UNION': union.  However,
     the value was not consistently being set to 0 for complex queries.
     (Bug #30377)

   * Queries that had a `GROUP BY' clause and selected `COUNT(DISTINCT
     BIT_COLUMN)' returned incorrect results.  (Bug #30324)

   * Using `DISTINCT' or `GROUP BY' on a *Note `BIT': numeric-types.
     column in a *Note `SELECT': select. statement caused the column to
     be cast internally as an integer, with incorrect results being
     returned from the query.  (Bug #30245)

   * Short-format *Note `mysql': mysql. commands embedded within `/*!
     ... */' comments were parsed incorrectly by *Note `mysql': mysql,
     which discarded the rest of the comment including the terminating
     `*/' characters. The result was a malformed (unclosed) comment. Now
     *Note `mysql': mysql. does not discard the `*/' characters.  (Bug
     #30164)

   * When *Note `mysqldump': mysqldump. wrote *Note `DROP DATABASE':
     drop-database. statements within version-specific comments, it
     included the terminating semicolon in the wrong place, causing
     following statements to fail when the dump file was reloaded.
     (Bug #30126)

   * If a view used a function in its *Note `SELECT': select.
     statement, the columns from the view were not inserted into the
     *Note `INFORMATION_SCHEMA.COLUMNS': columns-table. table.  (Bug
     #29408)

   * Killing an SSL connection on platforms where MySQL is compiled
     with `-DSIGNAL_WITH_VIO_CLOSE' (Windows, Mac OS X, and some
     others) could crash the server.  (Bug #28812)

   * A *Note `SELECT': select. in one connection could be blocked by
     *Note `INSERT ... ON DUPLICATE KEY UPDATE': insert-on-duplicate.
     in another connection even when `low_priority_updates' is set.
     (Bug #28587)

   * *Note `mysql_upgrade': mysql-upgrade. could run binaries
     dynamically linked against incorrect versions of shared libraries.
     (Bug #28560)

   * *Note `SHOW COLUMNS': show-columns. returned `NULL' instead of the
     empty string for the `Default' value of columns that had no default
     specified.  (Bug #27747)

   * With recent versions of DBD::mysql, *Note `mysqlhotcopy':
     mysqlhotcopy. generated table names that were doubly qualified
     with the database name.  (Bug #27694)

   * For `InnoDB' tables, *Note `CREATE TABLE a AS SELECT * FROM A':
     create-table-select. would fail.  (Bug #25164)

   * Under heavy load with a large query cache, invalidating part of
     the cache could cause the server to freeze (that is, to be unable
     to service other operations until the invalidation was complete).
     (Bug #21074) See also Bug #39253.

   * Worked around an `icc' problem with an incorrect machine
     instruction being generated in the context of software
     pre-fetching after a subroutine got in-lined.  (Upgrading to `icc'
     10.0.026 makes the workaround unnecessary.)  (Bug #20803)

   * Parameters of type *Note `DATETIME': datetime. or *Note `DATE':
     datetime. in stored procedures were silently converted to *Note
     `VARBINARY': binary-varbinary.  (Bug #13675)


File: manual.info,  Node: news-5-0-48,  Next: news-5-0-46,  Prev: news-5-0-50,  Up: news-5-0-x

D.1.50 Changes in MySQL Enterprise 5.0.48 [MRU] (27 August 2007)
----------------------------------------------------------------

This is a _Monthly Rapid Update_ release of the MySQL Enterprise Server
5.0.

*Important*:

This release was withdrawn from production and is no longer available.

This section documents all changes and bugfixes that have been applied
since the last last MySQL Enterprise Server release (5.0.46). If you
would like to receive more fine-grained and personalized _update
alerts_ about fixes that are relevant to the version and features you
use, please consider subscribing to _MySQL Enterprise_ (a commercial
MySQL offering). For more details please see
http://www.mysql.com/products/enterprise/advisors.html.

*Functionality Added or Changed*

   * If a `MyISAM' table is created with no `DATA DIRECTORY' option, the
     `.MYD' file is created in the database directory. By default, if
     `MyISAM' finds an existing `.MYD' file in this case, it overwrites
     it. The same applies to `.MYI' files for tables created with no
     `INDEX DIRECTORY' option. To suppress this behavior, start the
     server with the new `--keep_files_on_create' option, in which case
     `MyISAM' will not overwrite existing files and returns an error
     instead.  (Bug #29325)

   * MySQL source distributions are now available in Zip format.  (Bug
     #27742)

   * The `EXAMPLE' storage engine is now enabled by default.

*Bugs Fixed*

   * *Incompatible Change*: Failure to consider collation when
     comparing space characters could result in incorrect index entry
     order, leading to incorrect comparisons, inability to find some
     index values, misordered index entries, misordered `ORDER BY'
     results, or tables that *Note `CHECK TABLE': check-table. reports
     as having corrupt indexes.

     As a result of this bug fix, indexes must be rebuilt for columns
     that use any of these character sets: `eucjpms', `euc_kr',
     `gb2312', `latin7', `macce', `ujis'. See *Note
     checking-table-incompatibilities::.  (Bug #29461)

   * *MySQL Cluster*: Warnings and errors generated by *Note
     `ndb_config `--config-file=FILE'':
     mysql-cluster-programs-ndb-config.  were sent to `stdout', rather
     than to `stderr'.  (Bug #25941)

   * *MySQL Cluster*: When a cluster backup was terminated using the
     `ABORT BACKUP' command in the management client, a misleading
     error message `Backup aborted by application: Permanent error:
     Internal error' was returned. The error message returned in such
     cases now reads `Backup aborted by user request'.  (Bug #21052)

   * *MySQL Cluster*: Large file support did not work in AIX server
     binaries.  (Bug #10776)

   * *Replication*: *Note `SHOW SLAVE STATUS': show-slave-status.
     failed when slave I/O was about to terminate.  (Bug #34305)

   * *Replication*: The thread ID was not reset properly after
     execution of *Note `mysql_change_user()': mysql-change-user, which
     could cause replication failure when replicating temporary tables.
     (Bug #29734)

   * *Replication*: Operations that used the time zone replicated the
     time zone only for successful operations, but did not replicate
     the time zone for errors that need to know it.  (Bug #29536)

   * *Replication*: *Note `INSERT DELAYED': insert-delayed. statements
     on a master server are replicated as non-`DELAYED' inserts on
     slaves (which is normal, to preserve serialization), but the
     inserts on the slave did not use concurrent inserts. Now *Note
     `INSERT DELAYED': insert-delayed. on a slave is converted to a
     concurrent insert when possible, and to a normal insert otherwise.
     (Bug #29152)

   * *Replication*: An error that happened inside *Note `INSERT':
     insert, *Note `UPDATE': update, or *Note `DELETE': delete.
     statements performed from within a stored function or trigger
     could cause inconsistency between master and slave servers.  (Bug
     #27417)

   * *Replication*: Slave servers could incorrectly interpret an
     out-of-memory error from the master and reconnect using the wrong
     binary log position.  (Bug #24192)

   * Memory corruption occurred for some queries with a top-level `OR'
     operation in the `WHERE' condition if they contained equality
     predicates and other sargable predicates in disjunctive parts of
     the condition.  (Bug #30396)

   * The server created temporary tables for filesort operations in the
     working directory, not in the directory specified by the `tmpdir'
     system variable.  (Bug #30287)

   * The query cache does not support retrieval of statements for which
     column level access control applies, but the server was still
     caching such statements, thus wasting memory.  (Bug #30269)

   * `GROUP BY' on *Note `BIT': numeric-types. columns produced
     incorrect results.  (Bug #30219)

   * Using *Note `KILL QUERY': kill.  or *Note `KILL CONNECTION': kill.
     to kill a *Note `SELECT': select. statement caused a server crash
     if the query cache was enabled.  (Bug #30201)

   * Prepared statements containing `CONNECTION_ID()' could be written
     improperly to the binary log.  (Bug #30200)

   * When a thread executing a *Note `DROP TABLE': drop-table.
     statement was killed, the table name locks that had been acquired
     were not released.  (Bug #30193)

   * Use of local variables with non-ASCII names in stored procedures
     crashed the server.  (Bug #30120)

   * On Windows, client libraries lacked symbols required for linking.
     (Bug #30118)

   * `--myisam-recover=''' (empty option value) did not disable
     `MyISAM' recovery.  (Bug #30088)

   * The `IS_UPDATABLE' column in the *Note `INFORMATION_SCHEMA.VIEWS':
     views-table. table was not always set correctly.  (Bug #30020)

   * Statements within stored procedures ignored the value of the
     `low_priority_updates' system variable.  (Bug #29963) See also Bug
     #26162.

   * For `MyISAM' tables on Windows, *Note `INSERT': insert, *Note
     `DELETE': delete, or *Note `UPDATE': update. followed by *Note
     `ALTER TABLE': alter-table. within *Note `LOCK TABLES':
     lock-tables. could cause table corruption.  (Bug #29957)

   * With auto-reconnect enabled, row fetching for a prepared statement
     could crash after reconnect occurred because loss of the statement
     handler was not accounted for.  (Bug #29948)

   * *Note `LOCK TABLES': lock-tables. did not pre-lock tables used in
     triggers of the locked tables. Unexpected locking behavior and
     statement failures similar to `failed: 1100: Table 'XX' was not
     locked with LOCK TABLES' could result.  (Bug #29929)

   * `INSERT ... VALUES(CONNECTION_ID(), ...)' statements were written
     to the binary log in such a way that they could not be properly
     restored.  (Bug #29928)

   * Adding `DISTINCT' could cause incorrect rows to appear in a query
     result.  (Bug #29911)

   * Using the `DATE()' function in a `WHERE' clause did not return any
     records after encountering `NULL'. However, using `TRIM()' or
     `CAST()' produced the correct results.  (Bug #29898)

   * Very long prepared statements in stored procedures could cause a
     server crash.  (Bug #29856)

   * If query execution involved a temporary table, `GROUP_CONCAT()'
     could return a result with an incorrect character set.  (Bug
     #29850)

   * If one thread was performing concurrent inserts, other threads
     reading from the same table using equality key searches could see
     the index values for new rows before the data values had been
     written, leading to reports of table corruption.  (Bug #29838)

   * Repeatedly accessing a view in a stored procedure (for example, in
     a loop) caused a small amount of memory to be allocated per
     access. Although this memory is deallocated on disconnect, it
     could be a problem for a long running stored procedures that make
     repeated access of views.  (Bug #29834)

   * *Note `mysqldump': mysqldump. produced output that incorrectly
     discarded the `NO_AUTO_VALUE_ON_ZERO' value of the `sql_mode'
     variable after dumping triggers.  (Bug #29788)

   * An assertion failure occurred within yaSSL for very long keys.
     (Bug #29784) See also Bug #53463.

   * For `MEMORY' tables, the `index_merge' union access method could
     return incorrect results.  (Bug #29740)

   * Comparison of *Note `TIME': time. values using the `BETWEEN'
     operator led to string comparison, producing incorrect results in
     some cases. Now the values are compared as integers.  (Bug #29739)

   * For a table with a *Note `DATE': datetime. column DATE_COL such
     that selecting rows with `WHERE DATE_COL = 'DATE_VAL 00:00:00''
     yielded a nonempty result, adding `GROUP BY DATE_COL' caused the
     result to be empty.  (Bug #29729)

   * In some cases, `INSERT INTO ... SELECT ... GROUP BY' could insert
     rows even if the *Note `SELECT': select. by itself produced an
     empty result.  (Bug #29717)

   * For the embedded server, the *Note `mysql_stmt_store_result()':
     mysql-stmt-store-result. C API function caused a memory leak for
     empty result sets.  (Bug #29687)

   * *Note `EXPLAIN': explain. produced `Impossible where' for
     statements of the form `SELECT ... FROM t WHERE c=0', where `c'
     was an *Note `ENUM': enum.  column defined as a primary key.  (Bug
     #29661)

   * On Windows, *Note `ALTER TABLE': alter-table. hung if records were
     locked in share mode by a long-running transaction.  (Bug #29644)

   * A left join between two views could produce incorrect results.
     (Bug #29604)

   * Certain statements with unions, subqueries, and joins could result
     in huge memory consumption.  (Bug #29582)

   * Clients using SSL could hang the server.  (Bug #29579)

   * A slave running with `--log-slave-updates' would fail to write
     `INSERT DELAY IGNORE' statements to its binary log, resulting in
     different binary log contents on the master and slave.  (Bug
     #29571)

   * An incorrect result was returned when comparing string values that
     were converted to *Note `TIME': time.  values with `CAST()'.  (Bug
     #29555)

   * In the `ascii' character set, conversion of DEL (`0x7F') to
     Unicode incorrectly resulted in QUESTION MARK (`0x3F') rather than
     DEL.  (Bug #29499)

   * A field packet with `NULL' fields caused a `libmysqlclient' crash.
     (Bug #29494)

   * When using a combination of `HANDLER... READ' and *Note `DELETE':
     delete. on a table, MySQL continued to open new copies of the
     table every time, leading to an exhaustion of file descriptors.
     (Bug #29474) This regression was introduced by Bug #21587.

   * On Windows, the *Note `mysql': mysql. client died if the user
     entered a statement and Return after entering `Control+C'.  (Bug
     #29469)

   * Killing an *Note `INSERT DELAYED': insert-delayed. thread caused a
     server crash.  (Bug #29431)

   * The special `zero' *Note `ENUM': enum. value was coerced to the
     normal empty string *Note `ENUM': enum. value during a
     column-to-column copy. This affected `CREATE ... SELECT'
     statements and *Note `SELECT': select. statements with aggregate
     functions on *Note `ENUM': enum. columns in the `GROUP BY' clause.
     (Bug #29360)

   * Optimization of queries with `DETERMINISTIC' stored functions in
     the `WHERE' clause was ineffective: A sequential scan was always
     used.  (Bug #29338)

   * `MyISAM' corruption could occur with the `cp932_japanese_ci'
     collation for the `cp932' character set due to incorrect
     comparison for trailing space.  (Bug #29333)

   * The *Note `mysql_list_fields()': mysql-list-fields. C API function
     incorrectly set `MYSQL_FIELD::decimals' for some view columns.
     (Bug #29306)

   * `InnoDB' refused to start on some versions of FreeBSD with
     LinuxThreads. This is fixed by enabling file locking on FreeBSD.
     (Bug #29155)

   * A maximum of 4TB `InnoDB' free space was reported by `SHOW TABLE
     STATUS,' which is incorrect on systems with more than 4TB space.
     (Bug #29097)

   * A byte-order issue in writing a spatial index to disk caused bad
     index files on some systems.  (Bug #29070)

   * Creation of a legal stored procedure could fail if no default
     database had been selected.  (Bug #29050)

   * Coercion of ASCII values to character sets that are a superset of
     ASCII sometimes was not done, resulting in `illegal mix of
     collations' errors. These cases now are resolved using repertoire,
     a new string expression attribute (see *Note charset-repertoire::).
     (Bug #28875)

   * Fast *Note `ALTER TABLE': alter-table. (that works without
     rebuilding the table) acquired duplicate locks in the storage
     engine. In `MyISAM', if *Note `ALTER TABLE': alter-table. was
     issued under *Note `LOCK TABLE': lock-tables, it caused all data
     inserted after *Note `LOCK TABLE': lock-tables. to disappear.
     (Bug #28838)

   * Tables using the `InnoDB' storage engine incremented
     `AUTO_INCREMENT' values incorrectly with `ON DUPLICATE KEY UPDATE'.
     (Bug #28781)

   * Starting the server with an `innodb_force_recovery' value of 4 did
     not work.  (Bug #28604)

   * For `InnoDB' tables, MySQL unnecessarily sorted records in certain
     cases when the records were retrieved by `InnoDB' in the proper
     order already.  (Bug #28591)

   * *Note `mysql_install_db': mysql-install-db. could fail to find
     script files that it needs.  (Bug #28585)

   * If a stored procedure was created and invoked prior to selecting a
     default database with *Note `USE': use, a `No database selected'
     error occurred.  (Bug #28551)

   * On Mac OS X, shared-library installation path names were incorrect.
     (Bug #28544)

   * Using the `--skip-add-drop-table 'option with *Note `mysqldump':
     mysqldump. generated incorrect SQL if the database included any
     views. The recreation of views requires the creation and removal
     of temporary tables.  This option suppressed the removal of those
     temporary tables.  The same applied to `--compact' since this
     option also invokes `--skip-add-drop-table'.  (Bug #28524)

   * A race condition in the interaction between `MyISAM' and the query
     cache code caused the query cache not to invalidate itself for
     concurrently inserted data.  (Bug #28249)

   * Indexing column prefixes in `InnoDB' tables could cause table
     corruption.  (Bug #28138)

   * Index creation could fail due to truncation of key values to the
     maximum key length rather than to a mulitiple of the maximum
     character length.  (Bug #28125)

   * On Windows, symbols for yaSSL and taocrypt were missing from
     `mysqlclient.lib', resulting in unresolved symbol errors for
     clients linked against that library.  (Bug #27861)

   * Some *Note `SHOW': show. statements and `INFORMATION_SCHEMA'
     queries could expose information not permitted by the user's
     access privileges. An implication of this change is that *Note
     `SHOW TRIGGERS': show-triggers. and the *Note
     `INFORMATION_SCHEMA.TRIGGERS': triggers-table. table require the
     `TRIGGER'
     (http://dev.mysql.com/doc/refman/5.1/en/privileges-provided.html#priv_trigger)
     privilege, not `SUPER'.  (Bug #27629)

   * Some character mappings in the `ascii.xml' file were incorrect.

     As a result of this bug fix, indexes must be rebuilt for columns
     that use the `ascii_general_ci' collation for columns that contain
     any of these characters: `'`'', `'['', `'\'', `']'', `'~''. See
     *Note checking-table-incompatibilities::.  (Bug #27562)

   * A *Note `SELECT': select. with more than 31 nested dependent
     subqueries returned an incorrect result.  (Bug #27352)

   * *Note `INSERT INTO ... SELECT': insert-select. caused a crash if
     `innodb_locks_unsafe_for_binlog' was enabled.  (Bug #27294)

   * `FEDERATED' tables had an artificially low maximum of key length.
     (Bug #26909)

   * After the first read of a `TEMPORARY' table, *Note `CHECK TABLE':
     check-table. could report the table as being corrupt.  (Bug #26325)

   * If an operation had an `InnoDB' table, and two triggers, `AFTER
     UPDATE' and `AFTER INSERT', competing for different resources
     (such as two distinct `MyISAM' tables), the triggers were unable
     to execute concurrently. In addition, *Note `INSERT': insert. and
     *Note `UPDATE': update. statements for the `InnoDB' table were
     unable to run concurrently.  (Bug #26141)

   * *Note `ALTER DATABASE': alter-database. did not require at least
     one option.  (Bug #25859)

   * Using *Note `HANDLER': handler. to open a table having a storage
     engine not supported by *Note `HANDLER': handler. properly
     returned an error, but also improperly prevented the table from
     being dropped by other connections.  (Bug #25856)

   * When using a `FEDERATED' table, the value of `LAST_INSERT_ID()'
     would not correctly update the C API interface, which would affect
     the autogenerated ID returned both through the C API and the MySQL
     protocol, affecting Connectors that used the protocol or C API.
     (Bug #25714)

   * The server was blocked from opening other tables while the
     `FEDERATED' engine was attempting to open a remote table. Now the
     server does not check the correctness of a `FEDERATED' table at
     *Note `CREATE TABLE': create-table. time, but waits until the
     table actually is accessed.  (Bug #25679)

   * Several `InnoDB' assertion failures were corrected.  (Bug #25645)

   * In a stored function or trigger, when `InnoDB' detected deadlock,
     it attempted rollback and displayed an incorrect error message
     (`Explicit or implicit commit is not permitted in stored function
     or trigger'). Now `InnoDB' returns an error under these conditions
     and does not attempt rollback. Rollback is handled outside of
     `InnoDB' above the function/trigger level.  (Bug #24989)

   * Dropping a temporary `InnoDB' table that had been locked with
     *Note `LOCK TABLES': lock-tables.  caused a server crash.  (Bug
     #24918)

   * On Windows, executables did not include Vista manifests.  (Bug
     #24732) See also Bug #22563.

   * If MySQL/`InnoDB' crashed very quickly after starting up, it would
     not force a checkpoint. In this case, `InnoDB' would skip crash
     recovery at next startup, and the database would become corrupt.
     Now, if the redo log scan at `InnoDB' startup goes past the last
     checkpoint, crash recovery is forced.  (Bug #23710)

   * *Note `SHOW INNODB STATUS': show-innodb-status. caused an
     assertion failure under high load.  (Bug #22819)

   * A statement of the form *Note `CREATE TABLE IF NOT EXISTS t1
     SELECT f1() AS i': create-table-select. failed with a deadlock
     error if the stored function `f1()' referred to a table with the
     same name as the to-be-created table. Now it correctly produces a
     message that the table already exists.  (Bug #22427)

   * Read lock requests that were blocked by a pending write lock
     request were not permitted to proceed if the statement requesting
     the write lock was killed.  (Bug #21281)

   * On Windows, the server used 10MB of memory for each connection
     thread, resulting in memory exhaustion. Now each thread uses 1MB.
     (Bug #20815)

   * `InnoDB' produced an unnecessary (and harmless) warning:
     ``InnoDB': Error: trying to declare trx to enter `InnoDB', but
     `InnoDB': it already is declared'.  (Bug #20090)

   * `SQL_BIG_RESULT' had no effect for *Note `CREATE TABLE ... SELECT
     SQL_BIG_RESULT ...': create-table-select. statements.  (Bug #15130)

   * *Note `mysql_setpermission': mysql-setpermission. tried to grant
     global-only privileges at the database level.  (Bug #14618)

   * For the general query log, logging of prepared statements executed
     using the C API differed from logging of prepared statements
     performed with *Note `PREPARE': prepare.  and *Note `EXECUTE':
     execute. Logging for the latter was missing the `Prepare' and
     `Execute' lines.  (Bug #13326)

   * Backup software can cause `ERROR_SHARING_VIOLATION' or
     `ERROR_LOCK_VIOLATION' conditions during file operations. `InnoDB'
     now retries forever until the condition goes away.  (Bug #9709)


File: manual.info,  Node: news-5-0-46,  Next: news-5-0-45,  Prev: news-5-0-48,  Up: news-5-0-x

D.1.51 Changes in MySQL Enterprise 5.0.46 [MRU] (13 July 2007)
--------------------------------------------------------------

This is a _Monthly Rapid Update_ release of the MySQL Enterprise Server
5.0.

This section documents all changes and bugfixes that have been applied
since the last MySQL Enterprise Server release (5.0.44).  If you would
like to receive more fine-grained and personalized _update alerts_
about fixes that are relevant to the version and features you use,
please consider subscribing to _MySQL Enterprise_ (a commercial MySQL
offering). For more details please see
http://www.mysql.com/products/enterprise/advisors.html.

*Functionality Added or Changed*

   * *MySQL Cluster*: `auto_increment_increment' and
     `auto_increment_offset' are now supported for *Note `NDB':
     mysql-cluster. tables.  (Bug #26342)

   * *Replication*: The `sql_mode', `foreign_key_checks',
     `unique_checks', character set/collations, and `sql_auto_is_null'
     session variables are written to the binary log and honored during
     replication. See *Note binary-log::.

   * If a `MERGE' table cannot be opened or used because of a problem
     with an underlying table, *Note `CHECK TABLE': check-table. now
     displays information about which table caused the problem.  (Bug
     #26976)

*Bugs Fixed*

   * *MySQL Cluster*: When restarting a data node, queries could hang
     during that node's start phase 5, and continue only after the node
     had entered phase 6.  (Bug #29364)

   * *MySQL Cluster*: Replica redo logs were inconsistently handled
     during a system restart.  (Bug #29354)

   * *MySQL Cluster*: The management client's response to `START BACKUP
     WAIT COMPLETED' did not include the backup ID.  (Bug #27640)

   * *Replication*: *Note `DROP USER': drop-user. statements that named
     multiple users, only some of which could be dropped, were
     replicated incorrectly.  (Bug #29030)

   * On the IBM i5 platform, the installation script in the `.savf'
     binaries unconditionally executed the *Note `mysql_install_db':
     mysql-install-db. script.  (Bug #30084)

   * `gcov' coverage-testing information was not written if the server
     crashed.  (Bug #29543)

   * Corrupt data resulted from use of `SELECT ... INTO OUTFILE
     'FILE_NAME' FIELDS ENCLOSED BY 'C'', where C is a digit or minus
     sign, followed by `LOAD DATA INFILE 'FILE_NAME' FIELDS ENCLOSED BY
     'C''.  (Bug #29442)

   * Use of *Note `SHOW BINLOG EVENTS': show-binlog-events. for a
     nonexistent log file followed by *Note `PURGE BINARY LOGS':
     purge-binary-logs. caused a server crash.  (Bug #29420)

   * Assertion failure could occur for grouping queries that employed
     *Note `DECIMAL': numeric-types. user variables with assignments to
     them.  (Bug #29417)

   * For `CAST(EXPR AS DECIMAL(M,D))', the limits of 65 and 30 on the
     precision (M) and scale (D) were not enforced.  (Bug #29415)

   * Results for a select query that aliases the column names against a
     view could duplicate one column while omitting another. This bug
     could occur for a query over a multiple-table view that includes
     an `ORDER BY' clause in its definition.  (Bug #29392)

   * *Note `mysqldump': mysqldump. created a stray file when a given a
     too-long file name argument.  (Bug #29361)

   * `FULLTEXT' indexes could be corrupted by certain `gbk' characters.
     (Bug #29299)

   * *Note `SELECT ... INTO OUTFILE': select. followed by *Note `LOAD
     DATA': load-data. could result in garbled characters when the
     `FIELDS ENCLOSED BY' clause named a delimiter of `'0'', `'b'',
     `'n'', `'r'', `'t'', `'N'', or `'Z'' due to an interaction of
     character encoding and doubling for data values containing the
     enclosed-by character.  (Bug #29294)

   * Sort order of the collation wasn't used when comparing trailing
     spaces. This could lead to incorrect comparison results,
     incorrectly created indexes, or incorrect result set order for
     queries that include an `ORDER BY' clause.  (Bug #29261)

   * If an *Note `ENUM': enum. column contained `''' as one of its
     members (represented with numeric value greater than 0), and the
     column contained error values (represented as 0 and displayed as
     `'''), using *Note `ALTER TABLE': alter-table. to modify the
     column definition caused the 0 values to be given the numeric
     value of the nonzero `''' member.  (Bug #29251)

   * Calling *Note `mysql_options()': mysql-options. after *Note
     `mysql_real_connect()': mysql-real-connect. could cause clients to
     crash.  (Bug #29247)

   * *Note `CHECK TABLE': check-table. for `ARCHIVE' tables could
     falsely report table corruption or cause a server crash.  (Bug
     #29207)

   * Mixing binary and `utf8' columns in a union caused field lengths
     to be calculated incorrectly, resulting in truncation.  (Bug
     #29205)

   * `AsText()' could fail with a buffer overrun.  (Bug #29166)

   * *Note `LOCK TABLES': lock-tables. was not atomic when more than
     one `InnoDB' tables were locked.  (Bug #29154)

   * A network structure was initialized incorrectly, leading to
     embedded server crashes.  (Bug #29117)

   * An assertion failure occurred if a query contained a conjunctive
     predicate of the form ` VIEW_COLUMN = constant' in the `WHERE'
     clause and the `GROUP BY' clause contained a reference to a
     different view column. The fix also enables application of an
     optimization that was being skipped if a query contained a
     conjunctive predicate of the form `VIEW_COLUMN = constant' in the
     `WHERE' clause and the `GROUP BY' clause contained a reference to
     the same view column.  (Bug #29104)

   * If an *Note `INSERT INTO ... SELECT': insert-select. statement
     inserted into the same table that the *Note `SELECT': select.
     retrieved from, and the *Note `SELECT': select. included `ORDER
     BY' and `LIMIT' clauses, different data was inserted than the data
     produced by the *Note `SELECT': select. executed by itself.  (Bug
     #29095)

   * Queries that performed a lookup into a *Note `BINARY':
     binary-varbinary. index containing key values ending with spaces
     caused an assertion failure for debug builds and incorrect results
     for nondebug builds.  (Bug #29087)

   * The semantics of *Note `BIGINT': numeric-types. depended on
     platform-specific characteristics.  (Bug #29079)

   * If one of the queries in a *Note `UNION': union.  used the
     `SQL_CACHE' option and another query in the *Note `UNION': union.
     contained a nondeterministic function, the result was still
     cached. For example, this query was incorrectly cached:

          SELECT NOW() FROM t1 UNION SELECT SQL_CACHE 1 FROM t1;

     (Bug #29053)

   * *Note `REPLACE': replace, *Note `INSERT IGNORE': insert, and
     `UPDATE IGNORE' did not work for `FEDERATED' tables.  (Bug #29019)

   * Inserting into `InnoDB' tables and executing *Note `RESET MASTER':
     reset-master. in multiple threads cause assertion failure in debug
     server binaries.  (Bug #28983)

   * For a `ucs2' column, `GROUP_CONCAT()' did not convert separators
     to the result character set before inserting them, producing a
     result containing a mixture of two different character sets.  (Bug
     #28925)

   * Queries using UDFs or stored functions were cached.  (Bug #28921)

   * For a join with `GROUP BY' or `ORDER BY' and a view reference in
     the `FROM' list, the query metadata erroneously showed empty table
     aliases and database names for the view columns.  (Bug #28898)

   * Non-`utf8' characters could get mangled when stored in `CSV'
     tables.  (Bug #28862)

   * *Note `ALTER VIEW': alter-view. is not supported as a prepared
     statement but was not being rejected.  *Note `ALTER VIEW':
     alter-view. is now prohibited as a prepared statement or when
     called within stored routines.  (Bug #28846)

   * In strict SQL mode, errors silently stopped the SQL thread even
     for errors named using the `--slave-skip-errors' option.  (Bug
     #28839)

   * Runtime changes to the `log_queries_not_using_indexes' system
     variable were ignored.  (Bug #28808)

   * Selecting a column not present in the selected-from table caused
     an extra error to be produced by *Note `SHOW ERRORS': show-errors.
     (Bug #28677)

   * For a statement of the form `CREATE t1 SELECT INTEGER_CONSTANT',
     the server created the column using the *Note `DECIMAL':
     numeric-types. data type for large negative values that are within
     the range of *Note `BIGINT': numeric-types.  (Bug #28625)

   * When one thread attempts to lock two (or more) tables and another
     thread executes a statement that aborts these locks (such as *Note
     `REPAIR TABLE': repair-table, *Note `OPTIMIZE TABLE':
     optimize-table, or *Note `CHECK TABLE': check-table.), the thread
     might get a table object with an incorrect lock type in the table
     cache. The result is table corruption or a server crash.  (Bug
     #28574)

   * *Note `mysqlbinlog --hexdump': mysqlbinlog. generated incorrect
     output due to omission of the ``#'' comment character for some
     comment lines.  (Bug #28293)

   * The `LOCATE()' function returned `NULL' if any of its arguments
     evaluated to `NULL'. Likewise, the predicate, `LOCATE(STR,NULL) IS
     NULL', erroneously evaluated to `FALSE'.  (Bug #27932)

   * The modification of a table by a partially completed multi-column
     update was not recorded in the binlog, rather than being marked by
     an event and a corresponding error code.  (Bug #27716)

   * A stack overrun could occur when storing *Note `DATETIME':
     datetime. values using repeated prepared statements.  (Bug #27592)

   * Dropping a user-defined function could cause a server crash if the
     function was still in use by another thread.  (Bug #27564)

   * Unsafe aliasing in the source caused a client library crash when
     compiled with `gcc' 4 at high optimization levels.  (Bug #27383)

   * Index-based range reads could fail for comparisons that involved
     contraction characters (such as `ch' in Czech or `ll' in Spanish).
     (Bug #27345)

   * Aggregations in subqueries that refer to outer query columns were
     not always correctly referenced to the proper outer query.  (Bug
     #27333)

   * Error returns from the `time()' system call were ignored.  (Bug
     #27198)

   * Phantom reads could occur under `InnoDB' `SERIALIZABLE' isolation
     level.  (Bug #27197)

   * The `SUBSTRING()' function returned the entire string instead of
     an empty string when it was called from a stored procedure and
     when the length parameter was specified by a variable with the
     value ``0''.  (Bug #27130)

   * `ALTER TABLE ... ENABLE KEYS' could cause *Note `mysqld': mysqld.
     to crash when executed on a table containing on a `MyISAM' table
     containing billions of rows.  (Bug #27029)

   * Binary content `0x00' in a *Note `BLOB': blob. column sometimes
     became `0x5C 0x00' following a dump and reload, which could cause
     problems with data using multi-byte character sets such as `GBK'
     (Chinese). This was due to a problem with `SELECT INTO OUTFILE'
     whereby *Note `LOAD DATA': load-data. later incorrectly
     interpreted `0x5C' as the second byte of a multi-byte sequence
     rather than as the `SOLIDUS' (`\') character, used by MySQL as the
     escape character.  (Bug #26711)

   * Index creation could corrupt the table definition in the `.frm'
     file: 1) A table with the maximum number of key segments and
     maximum length key name would have a corrupted `.frm' file, due to
     incorrect calculation of the total key length. 2) `MyISAM' would
     reject a table with the maximum number of keys and the maximum
     number of key segments in all keys. (It would permit one less than
     this total maximum.) Now `MyISAM' accepts a table defined with the
     maximum.  (Bug #26642)

   * The index merge union access algorithm could produce incorrect
     results with `InnoDB' tables. The problem could also occur for
     queries that used `DISTINCT'.  (Bug #25798)

   * Under ActiveState Perl, `mysql-test-run.pl' could kill itself when
     attempting to kill other processes.  (Bug #25657)

   * A query with `DISTINCT' in the select list to which the loose-scan
     optimization for grouping queries was applied returned an
     incorrect result set when the query was used with the
     `SQL_BIG_RESULT' option.  (Bug #25602)

   * For a multiple-row insert into a `FEDERATED' table that refers to
     a remote transactional table, if the insert failed for a row due
     to constraint failure, the remote table would contain a partial
     commit (the rows preceding the failed one) instead of rolling back
     the statement completely. This occurred because the rows were
     treated as individual inserts.

     Now `FEDERATED' performs bulk-insert handling such that multiple
     rows are sent to the remote table in a batch.  This provides a
     performance improvement and enables the remote table to perform
     statement rollback properly should an error occur. This capability
     has the following limitations:

        * The size of the insert cannot exceed the maximum packet size
          between servers. If the insert exceeds this size, it is
          broken into multiple packets and the rollback problem can
          occur.

        * Bulk-insert handling does not occur for *Note `INSERT ... ON
          DUPLICATE KEY UPDATE': insert-on-duplicate.

     (Bug #25513)

   * The `FEDERATED' storage engine failed silently for *Note `INSERT
     ... ON DUPLICATE KEY UPDATE': insert-on-duplicate. if a duplicate
     key violation occurred. `FEDERATED' does not support `ON DUPLICATE
     KEY UPDATE', so now it correctly returns an `ER_DUP_KEY' error if
     a duplicate key violation occurs.  (Bug #25511)

   * A too-long `shared-memory-base-name' value could cause a buffer
     overflow and crash the server or clients.  (Bug #24924)

   * The server deducted some bytes from the `key_cache_block_size'
     option value and reduced it to the next lower 512 byte boundary.
     The resulting block size was not a power of two. Setting the
     `key_cache_block_size' system variable to a value that is not a
     power of two resulted in `MyISAM' table corruption.  (Bug #23068,
     Bug #28478, Bug #25853)

   * *Note `SHOW BINLOG EVENTS': show-binlog-events. displayed
     incorrect values of `End_log_pos' for events associated with
     transactional storage engines.  (Bug #22540)

   * Under ActiveState Perl, `mysql-test-run.pl' would not run.  (Bug
     #18415)

   * The server crashed when the size of an `ARCHIVE' table grew larger
     than 2GB.  (Bug #15787)

   * On 64-bit Windows systems, the Config Wizard failed to complete
     the setup because 64-bit Windows does not resolve dynamic linking
     of the 64-bit `libmysql.dll' to a 32-bit application like the
     Config Wizard.  (Bug #14649)

   * The server returned data from *Note `SHOW CREATE TABLE':
     show-create-table. statement or a *Note `SELECT': select.
     statement on an `INFORMATION_SCHEMA' table using the `binary'
     character set.  (Bug #10491)


File: manual.info,  Node: news-5-0-45,  Next: news-5-0-44sp1,  Prev: news-5-0-46,  Up: news-5-0-x

D.1.52 Changes in MySQL Community Server 5.0.45 (04 July 2007)
--------------------------------------------------------------

This is a bugfix release for the current MySQL Community Server
production release family. It replaces MySQL 5.0.41.

*Functionality Added or Changed*

   * *Incompatible Change*: Prior to this release, when *Note `DATE':
     datetime.  values were compared with *Note `DATETIME': datetime.
     values, the time portion of the *Note `DATETIME': datetime. value
     was ignored, or the comparison could be performed as a string
     compare. Now a *Note `DATE': datetime. value is coerced to the
     *Note `DATETIME': datetime. type by adding the time portion as
     `00:00:00'. To mimic the old behavior, use the `CAST()' function
     as shown in this example: `SELECT DATE_COL = CAST(NOW() AS DATE)
     FROM TABLE;'.  (Bug #28929)

   * *Incompatible Change*: *Note `INSERT DELAYED': insert-delayed. is
     now downgraded to a normal *Note `INSERT': insert. if the
     statement uses functions that access tables or triggers, or that
     is called from a function or a trigger.

     This was done to resolve the following interrelated issues:

        * The server could abort or deadlock for *Note `INSERT
          DELAYED': insert-delayed. statements for which another insert
          was performed implicitly (for example, using a stored
          function that inserted a row).

        * A trigger using an *Note `INSERT DELAYED': insert-delayed.
          caused the error `INSERT DELAYED can't be used with table ...
          because it is locked with LOCK TABLES' although the target
          table was not actually locked.

        * *Note `INSERT DELAYED': insert-delayed. into a table with a
          `BEFORE INSERT' or `AFTER INSERT' trigger gave an incorrect
          `NEW' pseudocolumn value and caused the server to deadlock or
          abort.

     (Bug #21483) See also Bug #20497, Bug #21714.

   * *MySQL Cluster*: The server source tree now includes scripts to
     simplify building MySQL with SCI support. For more information
     about SCI interconnects and these build scripts, see *Note
     mysql-cluster-sci-sockets::.  (Bug #25470)

   * Binaries for the Linux x86 statically linked `tar.gz' Community
     package were linked dynamically, not statically. Static linking
     has been re-enabled.  (Bug #29617)

   * *Note `INSERT DELAYED': insert-delayed. statements on `BLACKHOLE'
     tables are now rejected, due to the fact that the `BLACKHOLE'
     storage engine does not support them.  (Bug #27998)

   * A new status variable, `Com_call_procedure', indicates the number
     of calls to stored procedures.  (Bug #27994)

   * Potential memory leaks in *Note `SHOW PROFILE': show-profile. were
     eliminated.  (Bug #24795)

*Bugs Fixed*

   * *Security Fix*: A malformed password packet in the connection
     protocol could cause the server to crash. Thanks for Dormando for
     reporting this bug, and for providing details and a proof of
     concept.  (Bug #28984, CVE-2007-3780)

   * *Security Fix*: Use of a view could enable a user to gain update
     privileges for tables in other databases.  (Bug #27878,
     CVE-2007-3782)

   * *Security Fix*: The requirement of the `DROP' privilege for *Note
     `RENAME TABLE': rename-table. was not enforced.  (Bug #27515,
     CVE-2007-2691)

   * *Security Fix*: If a stored routine was declared using `SQL
     SECURITY INVOKER', a user who invoked the routine could gain
     privileges.  (Bug #27337, CVE-2007-2692)

   * *Security Fix*: *Note `CREATE TABLE LIKE': create-table. did not
     require any privileges on the source table. Now it requires the
     `SELECT' privilege.

     In addition, *Note `CREATE TABLE LIKE': create-table. was not
     isolated from alteration by other connections, which resulted in
     various errors and incorrect binary log order when trying to
     execute concurrently a *Note `CREATE TABLE LIKE': create-table.
     statement and either DDL statements on the source table or DML or
     DDL statements on the target table.  (Bug #23667, Bug #25578,
     CVE-2007-3781)

   * *Incompatible Change*: The names of stored functions referenced by
     views were not properly displayed by *Note `SHOW CREATE VIEW':
     show-create-view.

     The fix corrects a problem introduced by Bug #23491. There is an
     incompatibility when upgrading from versions affected by that bug
     fix (MySQL 5.0.40 through 5.0.43, MySQL 5.1.18 through 5.1.19): If
     you use *Note `mysqldump': mysqldump. before upgrading from an
     affected version and reload the data after upgrading to a higher
     version, you must drop and recreate your views.  (Bug #28605)

   * *Incompatible Change*: When *Note `mysqldump': mysqldump. was run
     with the `--delete-master-logs' option, binary log files were
     deleted before it was known that the dump had succeeded, not
     after. (The method for removing log files used *Note `RESET
     MASTER': reset-master. prior to the dump. This also reset the
     binary log sequence numbering to `.000001'.) Now *Note
     `mysqldump': mysqldump.  flushes the logs (which creates a new
     binary log number with the next sequence number), performs the
     dump, and then uses *Note `PURGE BINARY LOGS': purge-binary-logs.
     to remove the log files older than the new one. This also
     preserves log numbering because the new log with the next number
     is generated and only the preceding logs are removed. However,
     this may affect applications if they rely on the log numbering
     sequence being reset.  (Bug #24733)

   * *Incompatible Change*: The use of an `ORDER BY' or `DISTINCT'
     clause with a query containing a call to the `GROUP_CONCAT()'
     function caused results from previous queries to be redisplayed in
     the current result. The fix for this includes replacing a *Note
     `BLOB': blob. value used internally for sorting with a *Note
     `VARCHAR': char. This means that for long results (more than
     65,535 bytes), it is possible for truncation to occur; if so, an
     appropriate warning is issued.  (Bug #23856, Bug #28273)

   * *MySQL Cluster*: A corrupt schema file could cause a `File already
     open' error.  (Bug #28770)

   * *MySQL Cluster*: Setting `InitialNoOfOpenFiles'
     (http://dev.mysql.com/doc/refman/5.1/en/mysql-cluster-ndbd-definition.html#ndbparam-ndbd-initialnoofopenfiles)
     equal to `MaxNoOfOpenFiles' caused an error. This was due to the
     fact that the actual value of `MaxNoOfOpenFiles' as used by the
     cluster was offset by 1 from the value set in `config.ini'.  (Bug
     #28749)

   * *MySQL Cluster*: `UPDATE IGNORE' statements involving the primary
     keys of multiple tables could result in data corruption.  (Bug
     #28719)

   * *MySQL Cluster*: A race condition could result when nonmaster
     nodes (in addition to the master node) tried to update active
     status due to a local checkpoint (that is, between `NODE_FAILREP'
     and `COPY_GCIREQ' events). Now only the master updates the active
     status.  (Bug #28717)

   * *MySQL Cluster*: A fast global checkpoint under high load with
     high usage of the redo buffer caused data nodes to fail.  (Bug
     #28653)

   * *MySQL Cluster*: When an API node sent more than 1024 signals in a
     single batch, *Note `NDB': mysql-cluster. would process only the
     first 1024 of these, and then hang.  (Bug #28443)

   * *MySQL Cluster*: A delay in obtaining `AUTO_INCREMENT' IDs could
     lead to excess temporary errors.  (Bug #28410)

   * *MySQL Cluster*: The cluster waited 30 seconds instead of 30
     milliseconds before reading table statistics.  (Bug #28093)

   * *MySQL Cluster*: *Note `INSERT IGNORE': insert.  wrongly ignored
     `NULL' values in unique indexes.  (Bug #27980)

   * *MySQL Cluster*: The name of the month `March' was given
     incorrectly in the cluster error log.  (Bug #27926)

   * *MySQL Cluster*: It was not possible to add a unique index to an
     *Note `NDB': mysql-cluster. table while in single user mode.  (Bug
     #27710)

   * *MySQL Cluster*: Repeated insertion of data generated by *Note
     `mysqldump': mysqldump. into *Note `NDB': mysql-cluster. tables
     could eventually lead to failure of the cluster.  (Bug #27437)

   * *MySQL Cluster*: `ndb_connectstring' did not appear in the output
     of *Note `SHOW VARIABLES': show-variables.  (Bug #26675)

   * *MySQL Cluster*: A failure to release internal resources following
     an error could lead to problems with single user mode.  (Bug
     #25818)

   * *Replication*: The result of executing of a prepared statement
     created with `PREPARE s FROM "SELECT 1 LIMIT ?"' was not
     replicated correctly.  (Bug #28464)

   * *Replication*: Recreating a view that already exists on the master
     would cause a replicating slave to terminate replication with a
     'different error message on slave and master' error.  (Bug #28244)

   * *Replication*: Binary logging of prepared statements could produce
     syntactically incorrect queries in the binary log, replacing some
     parameters with variable names rather than variable values.  This
     could lead to incorrect results on replication slaves.  (Bug
     #26842, Bug #12826)

   * *Replication*: Connections from one *Note `mysqld': mysqld. server
     to another failed on Mac OS X, affecting replication and
     `FEDERATED' tables.  (Bug #26664) See also Bug #29083.

   * *Replication*: Aborting a statement on the master that applied to a
     nontransactional statement broke replication. The statement was
     written to the binary log but not completely executed on the
     master. Slaves receiving the statement executed it completely,
     resulting in loss of data synchrony. Now an error code is written
     to the error log so that the slaves stop without executing the
     aborted statement. (That is, replication stops, but synchrony to
     the point of the stop is preserved and you can investigate the
     problem.)  (Bug #26551)

   * *Replication*: Restoration of the default database after stored
     routine or trigger execution on a slave could cause replication to
     stop if the database no longer existed.  (Bug #25082)

   * *Replication*: When using transactions and replication, shutting
     down the master in the middle of a transaction would cause all
     slaves to stop replicating.  (Bug #22725)

   * *Replication*: Using *Note `CREATE TABLE LIKE ...': create-table.
     would raise an assertion when replicated to a slave.  (Bug #18950)

   * *Cluster API*: For *Note `BLOB': blob. reads on operations with
     lock mode `LM_CommittedRead', the lock mode was not upgraded to
     `LM_Read' before the state of the *Note `BLOB': blob. had already
     been calculated. The *Note `NDB': mysql-cluster. API methods
     affected by this problem included the following:

        * `NdbOperation::readTuple()'

        * `NdbScanOperation::readTuples()'

        * `NdbIndexScanOperation::readTuples()'

     (Bug #27320)

   * On the IBM i5 platform, the installation script in the `.savf'
     binaries unconditionally executed the *Note `mysql_install_db':
     mysql-install-db. script. This problem was fixed in a repackaged
     distribution numbered 5.0.45b.  (Bug #30084)

   * Long path names for internal temporary tables could cause stack
     overflows.  (Bug #29015)

   * Using an *Note `INTEGER': numeric-types. column from a table to
     `ROUND()' a number produced different results than using a
     constant with the same value as the *Note `INTEGER':
     numeric-types. column.  (Bug #28980)

   * If a program binds a given number of parameters to a prepared
     statement handle and then somehow changes `stmt->param_count' to a
     different number, *Note `mysql_stmt_execute()':
     mysql-stmt-execute. could crash the client or server.  (Bug #28934)

   * `INSERT .. ON DUPLICATE KEY UPDATE' could under some circumstances
     silently update rows when it should not have.  (Bug #28904)

   * Queries that used `UUID()' were incorrectly permitted into the
     query cache. (This should not happen because `UUID()' is
     nondeterministic.)  (Bug #28897)

   * Using a `VIEW' created with a nonexisting `DEFINER' could lead to
     incorrect results under some circumstances.  (Bug #28895)

   * On Windows, `USE_TLS' was not defined for `mysqlclient.lib'.  (Bug
     #28860)

   * A subquery with `ORDER BY' and `LIMIT 1' could cause a server
     crash.  (Bug #28811)

   * Using `BETWEEN' with nonindexed date columns and short formats of
     the date string could return incorrect results.  (Bug #28778)

   * Selecting `GEOMETRY' columns in a *Note `UNION': union. caused a
     server crash.  (Bug #28763)

   * When constructing the path to the original `.frm' file, `ALTER ..
     RENAME' was unnecessarily (and incorrectly) lowercasing the entire
     path when not on a case-insensitive file system, causing the
     statement to fail.  (Bug #28754)

   * Searches on indexed and nonindexed *Note `ENUM': enum. columns
     could return different results for empty strings.  (Bug #28729)

   * Executing *Note `EXPLAIN EXTENDED': explain. on a query using a
     derived table over a grouping subselect could lead to a server
     crash. This occurred only when materialization of the derived
     tables required creation of an auxiliary temporary table, an
     example being when a grouping operation was carried out with usage
     of a temporary table.  (Bug #28728)

   * The result of evaluation for a view's `CHECK OPTION' option over
     an updated record and records of merged tables was arbitrary and
     dependant on the order of records in the merged tables during the
     execution of the *Note `SELECT': select. statement.  (Bug #28716)

   * The `manager thread' of the LinuxThreads implementation was
     unintentionally started before *Note `mysqld': mysqld. had dropped
     privileges (to run as an unprivileged user). This caused signaling
     between threads in *Note `mysqld': mysqld. to fail when the
     privileges were finally dropped.  (Bug #28690)

   * For debug builds, *Note `ALTER TABLE': alter-table.  could trigger
     an assertion failure due to occurrence of a deadlock when
     committing changes.  (Bug #28652)

   * Killing from one connection a long-running `EXPLAIN QUERY' started
     from another connection caused *Note `mysqld': mysqld. to crash.
     (Bug #28598)

   * Outer join queries with `ON' conditions over constant outer tables
     did not return `NULL'-complemented rows when conditions were
     evaluated to `FALSE'.  (Bug #28571)

   * An update on a multiple-table view with the `CHECK OPTION' clause
     and a subquery in the `WHERE' condition could cause an assertion
     failure.  (Bug #28561)

   * `PURGE MASTER LOGS BEFORE (SUBQUERY)' caused a server crash.
     Subqueries are forbidden in the `BEFORE' clause now.  (Bug #28553)

   * *Note `mysqldump': mysqldump. calculated the required memory for a
     hex-blob string incorrectly causing a buffer overrun. This in turn
     caused *Note `mysqldump': mysqldump. to crash silently and produce
     incomplete output.  (Bug #28522)

   * Passing a *Note `DECIMAL': numeric-types. value as a parameter of
     a statement prepared with *Note `PREPARE': prepare. resulted in an
     error.  (Bug #28509)

   * *Note `mysql_affected_rows()': mysql-affected-rows. could return
     an incorrect result for *Note `INSERT ... ON DUPLICATE KEY
     UPDATE': insert-on-duplicate. if the `CLIENT_FOUND_ROWS' flag was
     set.  (Bug #28505)

   * A query that grouped by the result of an expression returned a
     different result when the expression was assigned to a user
     variable.  (Bug #28494)

   * Subselects returning `LONG' values in MySQL versions later than
     5.0.24a returned `LONGLONG' prior to this. The previous behavior
     was restored.  (Bug #28492) This regression was introduced by Bug
     #19714.

   * Forcing the use of an index on a *Note `SELECT': select. query
     when the index had been disabled would raise an error without
     running the query.  The query now executes, with a warning
     generated noting that the use of a disabled index has been ignored.
     (Bug #28476)

   * The query `SELECT '2007-01-01' + INTERVAL COLUMN_NAME DAY FROM
     TABLE_NAME' caused *Note `mysqld': mysqld. to fail.  (Bug #28450)

   * A server crash could happen under rare conditions such that a
     temporary table outgrew heap memory reserved for it and the
     remaining disk space was not big enough to store the table as a
     `MyISAM' table.  (Bug #28449)

   * *Note `mysql_upgrade': mysql-upgrade. failed if certain SQL modes
     were set. Now it sets the mode itself to avoid this problem.  (Bug
     #28401)

   * A query with a `NOT IN' subquery predicate could cause a crash
     when the left operand of the predicate evaluated to `NULL'.  (Bug
     #28375)

   * The test case for *Note `mysqldump': mysqldump. failed with
     `bin-log' disabled.  (Bug #28372)

   * Attempting to `LOAD_FILE' from an empty floppy drive under
     Windows, caused the server to hang. For example, if you opened a
     connection to the server and then issued the command `SELECT
     LOAD_FILE('a:test');', with no floppy in the drive, the server was
     inaccessible until the modal pop-up dialog box was dismissed.
     (Bug #28366)

   * A buffer overflow could occur when using *Note `DECIMAL':
     numeric-types. columns on Windows operating systems.  (Bug #28361)

   * `libmysql.dll' could not be dynamically loaded on Windows.  (Bug
     #28358)

   * Grouping queries with correlated subqueries in `WHERE' conditions
     could produce incorrect results.  (Bug #28337)

   * `mysqltest' used a too-large stack size on PowerPC/Debian Linux,
     causing thread-creation failure for tests that use many threads.
     (Bug #28333)

   * *Note `EXPLAIN': explain. for a query on an empty table
     immediately after its creation could result in a server crash.
     (Bug #28272)

   * The `IS_UPDATABLE' column in the *Note `INFORMATION_SCHEMA.VIEWS':
     views-table. table was not always set correctly.  (Bug #28266)

   * Comparing a *Note `DATETIME': datetime. column value with a user
     variable yielded incorrect results.  (Bug #28261)

   * For `CAST()' of a `NULL' value with type *Note `DECIMAL':
     numeric-types, the return value was incorrectly initialized,
     producing a runtime error for binaries built using Visual C++ 2005.
     (Bug #28250)

   * Portability problems caused by use of `isinf()' were corrected.
     (Bug #28240)

   * When dumping procedures, *Note `mysqldump `--compact' ':
     mysqldump. generated output that restored the session variable
     `sql_mode' without first capturing it. When dumping routines,
     *Note `mysqldump `--compact' ': mysqldump. neither set nor
     retrieved the value of `sql_mode'.  (Bug #28223)

   * Comparison of the string value of a date showed as unequal to
     `CURTIME()'. Similar behavior was exhibited for *Note `DATETIME':
     datetime. values.  (Bug #28208)

   * For `InnoDB', in some rare cases the optimizer preferred a more
     expensive `ref' access to a less expensive range access.  (Bug
     #28189)

   * A performance degradation was observed for outer join queries to
     which a not-exists optimization was applied.  (Bug #28188)

   * `SELECT * INTO OUTFILE ... FROM INFORMATION_SCHEMA.SCHEMATA'
     failed with an `Access denied' error, even for a user who had the
     `FILE' privilege.  (Bug #28181)

   * The `Bytes_received' and `Bytes_sent' status variables could hold
     only 32-bit values (not 64-bit values) on some platforms.  (Bug
     #28149)

   * Comparisons of *Note `DATE': datetime. or *Note `DATETIME':
     datetime. values for the `IN()' function could yield incorrect
     results.  (Bug #28133)

   * Storing a large number into a *Note `FLOAT': numeric-types. or
     *Note `DOUBLE': numeric-types. column with a fixed length could
     result in incorrect truncation of the number if the column's
     length was greater than 31.  (Bug #28121)

   * The server could hang for `INSERT IGNORE ... ON DUPLICATE KEY
     UPDATE' if an update failed.  (Bug #28000)

   * *Note `DECIMAL': numeric-types. values beginning with nine `9'
     digits could be incorrectly rounded.  (Bug #27984)

   * `CAST()' to *Note `DECIMAL': numeric-types. did not check for
     overflow.  (Bug #27957)

   * For *Note `INSERT ... ON DUPLICATE KEY UPDATE':
     insert-on-duplicate. statements that affected many rows, updates
     could be applied to the wrong rows.  (Bug #27954)

   * Early `NULL'-filtering optimization did not work for `eq_ref'
     table access.  (Bug #27939)

   * The second execution of a prepared statement from a *Note `UNION':
     union. query with `ORDER BY RAND()' caused the server to crash.
     This problem could also occur when invoking a stored procedure
     containing such a query.  (Bug #27937)

   * Views ignored precision for `CAST()' operations.  (Bug #27921)

   * For attempts to open a nonexistent table, the server should report
     `ER_NO_SUCH_TABLE' but sometimes reported `ER_TABLE_NOT_LOCKED'.
     (Bug #27907)

   * A stored program that uses a variable name containing multibyte
     characters could fail to execute.  (Bug #27876)

   * Nongrouped columns were permitted by `*' in `ONLY_FULL_GROUP_BY'
     SQL mode.  (Bug #27874)

   * `ON' conditions from `JOIN' expressions were ignored when checking
     the `CHECK OPTION' clause while updating a multiple-table view
     that included such a clause.  (Bug #27827)

   * Debug builds on Windows generated false alarms about uninitialized
     variables with some Visual Studio runtime libraries.  (Bug #27811)

   * Certain queries that used uncorrelated scalar subqueries caused
     *Note `EXPLAIN': explain. to crash.  (Bug #27807)

   * Changes to some system variables should invalidate statements in
     the query cache, but invalidation did not happen.  (Bug #27792)

   * Performing a *Note `UNION': union. on two views that had `ORDER
     BY' clauses resulted in an `Unknown column' error.  (Bug #27786)

   * *Note `mysql_install_db': mysql-install-db. is supposed to detect
     existing system tables and create only those that do not exist.
     Instead, it was exiting with an error if tables already existed.
     (Bug #27783)

   * On some systems, `udf_example.c' returned an incorrect result
     length. Also on some systems, `mysql-test-run.pl' could not find
     the shared object built from `udf_example.c'.  (Bug #27741)

   * *Note `mysqld': mysqld. did not check the length of option values
     and could crash with a buffer overflow for long values.  (Bug
     #27715)

   * Comparisons using row constructors could fail for rows containing
     `NULL' values.  (Bug #27704)

   * *Note `LOAD DATA': load-data. did not use `CURRENT_TIMESTAMP' as
     the default value for a *Note `TIMESTAMP': datetime. column for
     which no value was provided.  (Bug #27670)

   * *Note `mysqldump': mysqldump. could not connect using SSL.  (Bug
     #27669)

   * On Linux, the server could not create temporary tables if
     `lower_case_table_names' was set to 1 and the value of `tmpdir'
     was a directory name containing any uppercase letters.  (Bug
     #27653)

   * For `InnoDB' tables, a multiple-row *Note `INSERT': insert. of the
     form `INSERT INTO t (id...) VALUES (NULL...) ON DUPLICATE KEY
     UPDATE id=VALUES(id)', where `id' is an `AUTO_INCREMENT' column,
     could cause `ERROR 1062 (23000): Duplicate entry...' errors or
     lost rows.  (Bug #27650)

   * `HASH' indexes on *Note `VARCHAR': char. columns with binary
     collations did not ignore trailing spaces from strings before
     comparisons. This could result in duplicate records being
     successfully inserted into a `MEMORY' table with unique key
     constraints. A consequence was that internal `MEMORY' tables used
     for `GROUP BY' calculation contained duplicate rows that resulted
     in duplicate-key errors when converting those temporary tables to
     `MyISAM', and that error was incorrectly reported as a `table is
     full' error.  (Bug #27643)

   * The XML output representing an empty result was an empty string
     rather than an empty `<resultset/>' element.  (Bug #27608)

   * An error occurred trying to connect to *Note `mysqld-debug.exe':
     mysqld.  (Bug #27597)

   * Comparison of a *Note `DATE': datetime. with a *Note `DATETIME':
     datetime. did not treat the *Note `DATE': datetime. as having a
     time part of `00:00:00'.  (Bug #27590) See also Bug #32198.

   * Selecting `MIN()' on an indexed column that contained only `NULL'
     values caused `NULL' to be returned for other result columns.
     (Bug #27573)

   * If a stored function or trigger was killed, it aborted but no
     error was thrown, permitting the calling statement to continue
     without noticing the problem. This could lead to incorrect results.
     (Bug #27563)

   * The fix for Bug #17212 provided correct sort order for misordered
     output of certain queries, but caused significant overall query
     performance degradation. (Results were correct (good), but
     returned much more slowly (bad).) The fix also affected
     performance of queries for which results were correct.  The
     performance degradation has been addressed.  (Bug #27531)

   * The `CRC32()' function returns an unsigned integer, but the
     metadata was signed, which could cause certain queries to return
     incorrect results. (For example, queries that selected a `CRC32()'
     value and used that value in the `GROUP BY' clause.)  (Bug #27530)

   * An interaction between *Note `SHOW TABLE STATUS':
     show-table-status. and other concurrent statements that modify the
     table could result in a divide-by-zero error and a server crash.
     (Bug #27516)

   * When *Note `ALTER TABLE': alter-table. was used to add a new *Note
     `DATE': datetime. column with no explicit default value,
     `'0000-00-00'' was used as the default even if the SQL mode
     included the `NO_ZERO_DATE' mode to prohibit that value. A similar
     problem occurred for *Note `DATETIME': datetime. columns.  (Bug
     #27507)

   * A race condition between *Note `DROP TABLE': drop-table. and *Note
     `SHOW TABLE STATUS': show-table-status. could cause the latter to
     display incorrect information.  (Bug #27499)

   * Using a *Note `TEXT': blob. local variable in a stored routine in
     an expression such as `SET VAR = SUBSTRING(VAR, 3)' produced an
     incorrect result.  (Bug #27415)

   * Nested aggregate functions could be improperly evaluated.  (Bug
     #27363)

   * A stored function invocation in the `WHERE' clause was treated as
     a constant.  (Bug #27354)

   * Failure to allocate memory associated with
     `transaction_prealloc_size' could cause a server crash.  (Bug
     #27322)

   * *Note `mysqldump': mysqldump. crashed if it got no data from *Note
     `SHOW CREATE PROCEDURE': show-create-procedure. (for example, when
     trying to dump a routine defined by a different user and for which
     the current user had no privileges). Now it prints a comment to
     indicate the problem. It also returns an error, or continues if
     the `--force' option is given.  (Bug #27293)

   * The error message for error number `137' did not report which
     database/table combination reported the problem.  (Bug #27173)

   * *Note `mysqlbinlog': mysqlbinlog. produced different output with
     the `-R' option than without it.  (Bug #27171)

   * A large filesort could result in a division by zero error and a
     server crash.  (Bug #27119)

   * Times displayed by *Note `SHOW PROFILE': show-profile.  were
     incorrectly associated with the profile entry one later than the
     correct one.  (Bug #27060)

   * Flow control optimization in stored routines could cause exception
     handlers to never return or execute incorrect logic.  (Bug #26977)

   * *Note `SHOW PROFILE': show-profile. hung if executed before
     enabling the `@@profiling' session variable.  (Bug #26938)

   * *Note `mysqldump': mysqldump. would not dump a view for which the
     `DEFINER' no longer exists.  (Bug #26817)

   * Creating a temporary table with `InnoDB' when using the
     one-file-per-table setting, and when the host file system for
     temporary tables was `tmpfs', would cause an assertion within
     `mysqld'. This was due to the use of `O_DIRECT' when opening the
     temporary table file.  (Bug #26662)

   * *Note `mysql_upgrade': mysql-upgrade. did not detect failure of
     external commands that it runs.  (Bug #26639)

   * Some test suite files were missing from some MySQL-test packages.
     (Bug #26609)

   * Statements within triggers ignored the value of the
     `low_priority_updates' system variable.  (Bug #26162) See also Bug
     #29963.

   * Index hints (`USE INDEX', `IGNORE INDEX', `FORCE INDEX') cannot be
     used with `FULLTEXT' indexes, but were not being ignored.  (Bug
     #25951)

   * If *Note `CREATE TABLE t1 LIKE t2': create-table. failed due to a
     full disk, an empty `t2.frm' file could be created but not
     removed. This file then caused subsequent attempts to create a
     table named `t2' to fail. This is easily corrected at the file
     system level by removing the `t2.frm' file manually, but now the
     server removes the file if the create operation does not complete
     successfully.  (Bug #25761)

   * Running *Note `CHECK TABLE': check-table. concurrently with a
     *Note `SELECT': select, *Note `INSERT': insert. or other statement
     on Windows could corrupt a MyISAM table.  (Bug #25712)

   * On Windows, connection handlers did not properly decrement the
     server's thread count when exiting.  (Bug #25621)

   * *Note `mysql_upgrade': mysql-upgrade. did not pass a password to
     *Note `mysqlcheck': mysqlcheck. if one was given.  (Bug #25452)

   * On Windows, *Note `mysql_upgrade': mysql-upgrade. was sensitive to
     lettercase of the names of some required components.  (Bug #25405)

   * For storage engines that permit the current auto-increment value
     to be set, using `ALTER TABLE ... ENGINE' to convert a table from
     one such storage engine to another caused loss of the current
     value. (For storage engines that do not support setting the value,
     it cannot be retained anyway when changing the storage engine.)
     (Bug #25262)

   * Due to a race condition, executing *Note `FLUSH PRIVILEGES':
     flush. in one thread could cause brief table unavailability in
     other threads.  (Bug #24988)

   * Several math functions produced incorrect results for large
     unsigned values. `ROUND()' produced incorrect results or a crash
     for a large number-of-decimals argument.  (Bug #24912)

   * The result set of a query that used `WITH ROLLUP' and `DISTINCT'
     could lack some rollup rows (rows with `NULL' values for grouping
     attributes) if the `GROUP BY' list contained constant expressions.
     (Bug #24856)

   * For queries that used `ORDER BY' with `InnoDB' tables, if the
     optimizer chose an index for accessing the table but found a
     covering index that enabled the `ORDER BY' to be skipped, no
     results were returned.  (Bug #24778)

   * Concurrent execution of *Note `CREATE TABLE ... SELECT':
     create-table. and other statements involving the target table
     suffered from various race conditions, some of which might have
     led to deadlocks.  (Bug #24738)

   * On some Linux distributions where LinuxThreads and NPTL `glibc'
     versions both are available, statically built binaries can crash
     because the linker defaults to LinuxThreads when linking
     statically, but calls to external libraries (such as `libnss') are
     resolved to NPTL versions. This cannot be worked around in the
     code, so instead if a crash occurs on such a binary/OS
     combination, print an error message that provides advice about how
     to fix the problem.  (Bug #24611)

   * An attempt to execute *Note `CREATE TABLE ... SELECT':
     create-table. when a temporary table with the same name already
     existed led to the insertion of data into the temporary table and
     creation of an empty nontemporary table.  (Bug #24508)

   * The `MERGE' storage engine could return incorrect results when
     several index values that compare equality were present in an
     index (for example, `'gross'' and `'gross '', which are considered
     equal but have different lengths).  (Bug #24342)

   * Some upgrade problems are detected and better error messages
     suggesting that *Note `mysql_upgrade': mysql-upgrade. be run are
     produced.  (Bug #24248)

   * Some views could not be created even when the user had the
     requisite privileges.  (Bug #24040)

   * Using `CAST()' to convert *Note `DATETIME': datetime. values to
     numeric values did not work.  (Bug #23656)

   * The `AUTO_INCREMENT' value would not be correctly reported for
     `InnoDB' tables when using *Note `SHOW CREATE TABLE':
     show-create-table. statement or *Note `mysqldump': mysqldump.
     command.  (Bug #23313)

   * Implicit conversion of `9912101' to *Note `DATE': datetime. did
     not match `CAST(9912101 AS DATE)'.  (Bug #23093)

   * Conversion errors could occur when constructing the condition for
     an `IN' predicate. The predicate was treated as if the affected
     column contains `NULL', but if the `IN' predicate is inside `NOT',
     incorrect results could be returned.  (Bug #22855)

   * `SELECT COUNT(*)' from a table containing a `DATETIME NOT NULL'
     column could produce spurious warnings with the `NO_ZERO_DATE' SQL
     mode enabled.  (Bug #22824)

   * Using *Note `SET GLOBAL': set-option. to change the
     `lc_time_names' system variable had no effect on new connections.
     (Bug #22648)

   * A multiple-table *Note `UPDATE': update. could return an incorrect
     rows-matched value if, during insertion of rows into a temporary
     table, the table had to be converted from a `MEMORY' table to a
     `MyISAM' table.  (Bug #22364)

   * yaSSL crashed on pre-Pentium Intel CPUs.  (Bug #21765)

   * Linux binaries were unable to dump core after executing a
     `setuid()' call.  (Bug #21723)

   * A slave that used `--master-ssl-cipher' could not connect to the
     master.  (Bug #21611)

   * Quoted labels in stored routines were mishandled, rendering the
     routines unusable.  (Bug #21513)

   * Stack overflow caused server crashes.  (Bug #21476)

   * `CURDATE()' is less than `NOW()', either when comparing
     `CURDATE()' directly (`CURDATE() < NOW()' is true) or when casting
     `CURDATE()' to *Note `DATE': datetime. (`CAST(CURDATE() AS DATE) <
     NOW()' is true). However, storing `CURDATE()' in a *Note `DATE':
     datetime. column and comparing `COL_NAME < NOW()' incorrectly
     yielded false. This is fixed by comparing a *Note `DATE':
     datetime. column as *Note `DATETIME': datetime. for comparisons to
     a *Note `DATETIME': datetime. constant.  (Bug #21103)

   * *Note `CREATE TABLE IF NOT EXISTS ... SELECT':
     create-table-select. caused a server crash if the target table
     already existed and had a `BEFORE INSERT' trigger.  (Bug #20903)

   * Deadlock occurred for attempts to execute *Note `CREATE TABLE IF
     NOT EXISTS ... SELECT': create-table-select. when *Note `LOCK
     TABLES': lock-tables. had been used to acquire a read lock on the
     target table.  (Bug #20662, Bug #15522)

   * Changing a `utf8' column in an `InnoDB' table to a shorter length
     did not shorten the data values.  (Bug #20095)

   * For dates with 4-digit year parts less than 200, an incorrect
     implicit conversion to add a century was applied for date
     arithmetic performed with `DATE_ADD()', `DATE_SUB()', `+
     INTERVAL', and `- INTERVAL'. (For example, `DATE_ADD('0050-01-01
     00:00:00', INTERVAL 0 SECOND)' became `'2050-01-01 00:00:00''.)
     (Bug #18997)

   * Granting access privileges to an individual table where the
     database or table name contained an underscore would fail.  (Bug
     #18660)

   * The `-lmtmalloc' library was removed from the output of *Note
     `mysql_config': mysql-config. on Solaris, as it caused problems
     when building `DBD::mysql' (and possibly other applications) on
     that platform that tried to use `dlopen()' to access the client
     library.  (Bug #18322)

   * The `check-cpu' script failed to detect AMD64 Turion processors
     correctly.  (Bug #17707)

   * Trying to shut down the server following a failed *Note `LOAD DATA
     INFILE': load-data. caused *Note `mysqld': mysqld. to crash.  (Bug
     #17233)

   * The omission of leading zeros in dates could lead to erroneous
     results when these were compared with the output of certain date
     and time functions.  (Bug #16377)

   * `INSERT...ON DUPLICATE KEY UPDATE' could cause `Error 1032: Can't
     find record in ...' for inserts into an `InnoDB' table unique index
     using key column prefixes with an underlying `utf8' string column.
     (Bug #13191)

   * Having the `EXECUTE' privilege for a routine in a database should
     make it possible to *Note `USE': use. that database, but the server
     returned an error instead. This has been corrected. As a result of
     the change, *Note `SHOW TABLES': show-tables. for a database in
     which you have only the `EXECUTE' privilege returns an empty set
     rather than an error.  (Bug #9504)


File: manual.info,  Node: news-5-0-44sp1,  Next: news-5-0-44,  Prev: news-5-0-45,  Up: news-5-0-x

D.1.53 Changes in MySQL Enterprise 5.0.44sp1 [QSP] (01 August 2007)
-------------------------------------------------------------------

This is a _Service Pack_ release of the MySQL Enterprise Server 5.0.

This section documents all changes and bug fixes that have been applied
since the last MySQL Enterprise Server release (5.0.44).

*Bugs Fixed*

   * Using the `DATE()' function in a `WHERE' clause did not return any
     records after encountering `NULL'. However, using `TRIM()' or
     `CAST()' produced the correct results.  (Bug #29898)

   * For a table with a *Note `DATE': datetime. column DATE_COL such
     that selecting rows with `WHERE DATE_COL = 'DATE_VAL 00:00:00''
     yielded a nonempty result, adding `GROUP BY DATE_COL' caused the
     result to be empty.  (Bug #29729)

   * Optimization of queries with `DETERMINISTIC' stored functions in
     the `WHERE' clause was ineffective: A sequential scan was always
     used.  (Bug #29338)

   * Creation of a legal stored procedure could fail if no default
     database had been selected.  (Bug #29050)

   * If a stored procedure was created and invoked prior to selecting a
     default database with *Note `USE': use, a `No database selected'
     error occurred.  (Bug #28551)


File: manual.info,  Node: news-5-0-44,  Next: news-5-0-42,  Prev: news-5-0-44sp1,  Up: news-5-0-x

D.1.54 Changes in MySQL Enterprise 5.0.44 [MRU] (21 June 2007)
--------------------------------------------------------------

This is a _Monthly Rapid Update_ release of the MySQL Enterprise Server
5.0.

This section documents all changes and bug fixes that have been applied
since the last MySQL Enterprise Server release (5.0.42).

*Functionality Added or Changed*

   * *MySQL Cluster*: The server source tree now includes scripts to
     simplify building MySQL with SCI support. For more information
     about SCI interconnects and these build scripts, see *Note
     mysql-cluster-sci-sockets::.  (Bug #25470)

   * Enterprise builds did not include the `CSV' storage engine. `CSV'
     is now included in Enterprise builds for all platforms except
     Windows, QNX, and NetWare.  (Bug #28844)

   * *Note `INSERT DELAYED': insert-delayed. statements on `BLACKHOLE'
     tables are now rejected, due to the fact that the `BLACKHOLE'
     storage engine does not support them.  (Bug #27998)

   * A new status variable, `Com_call_procedure', indicates the number
     of calls to stored procedures.  (Bug #27994)

*Bugs Fixed*

   * *Security Fix*: A malformed password packet in the connection
     protocol could cause the server to crash. Thanks for Dormando for
     reporting this bug, and for providing details and a proof of
     concept.  (Bug #28984, CVE-2007-3780)

   * *Security Fix*: *Note `CREATE TABLE LIKE': create-table. did not
     require any privileges on the source table. Now it requires the
     `SELECT' privilege.

     In addition, *Note `CREATE TABLE LIKE': create-table. was not
     isolated from alteration by other connections, which resulted in
     various errors and incorrect binary log order when trying to
     execute concurrently a *Note `CREATE TABLE LIKE': create-table.
     statement and either DDL statements on the source table or DML or
     DDL statements on the target table.  (Bug #23667, Bug #25578,
     CVE-2007-3781)

   * *Incompatible Change*: The names of stored functions referenced by
     views were not properly displayed by *Note `SHOW CREATE VIEW':
     show-create-view.

     The fix corrects a problem introduced by Bug #23491. There is an
     incompatibility when upgrading from versions affected by that bug
     fix (MySQL 5.0.40 through 5.0.43, MySQL 5.1.18 through 5.1.19): If
     you use *Note `mysqldump': mysqldump. before upgrading from an
     affected version and reload the data after upgrading to a higher
     version, you must drop and recreate your views.  (Bug #28605)

   * *Incompatible Change*: When *Note `mysqldump': mysqldump. was run
     with the `--delete-master-logs' option, binary log files were
     deleted before it was known that the dump had succeeded, not
     after. (The method for removing log files used *Note `RESET
     MASTER': reset-master. prior to the dump. This also reset the
     binary log sequence numbering to `.000001'.) Now *Note
     `mysqldump': mysqldump.  flushes the logs (which creates a new
     binary log number with the next sequence number), performs the
     dump, and then uses *Note `PURGE BINARY LOGS': purge-binary-logs.
     to remove the log files older than the new one. This also
     preserves log numbering because the new log with the next number
     is generated and only the preceding logs are removed. However,
     this may affect applications if they rely on the log numbering
     sequence being reset.  (Bug #24733)

   * *Incompatible Change*: The use of an `ORDER BY' or `DISTINCT'
     clause with a query containing a call to the `GROUP_CONCAT()'
     function caused results from previous queries to be redisplayed in
     the current result. The fix for this includes replacing a *Note
     `BLOB': blob. value used internally for sorting with a *Note
     `VARCHAR': char. This means that for long results (more than
     65,535 bytes), it is possible for truncation to occur; if so, an
     appropriate warning is issued.  (Bug #23856, Bug #28273)

   * *MySQL Cluster*: A corrupt schema file could cause a `File already
     open' error.  (Bug #28770)

   * *MySQL Cluster*: `UPDATE IGNORE' statements involving the primary
     keys of multiple tables could result in data corruption.  (Bug
     #28719)

   * *MySQL Cluster*: A race condition could result when nonmaster
     nodes (in addition to the master node) tried to update active
     status due to a local checkpoint (that is, between `NODE_FAILREP'
     and `COPY_GCIREQ' events). Now only the master updates the active
     status.  (Bug #28717)

   * *MySQL Cluster*: A fast global checkpoint under high load with
     high usage of the redo buffer caused data nodes to fail.  (Bug
     #28653)

   * *MySQL Cluster*: When an API node sent more than 1024 signals in a
     single batch, *Note `NDB': mysql-cluster. would process only the
     first 1024 of these, and then hang.  (Bug #28443)

   * *MySQL Cluster*: A delay in obtaining `AUTO_INCREMENT' IDs could
     lead to excess temporary errors.  (Bug #28410)

   * *MySQL Cluster*: A failure to release internal resources following
     an error could lead to problems with single user mode.  (Bug
     #25818)

   * *Replication*: The result of executing of a prepared statement
     created with `PREPARE s FROM "SELECT 1 LIMIT ?"' was not
     replicated correctly.  (Bug #28464)

   * *Replication*: Recreating a view that already exists on the master
     would cause a replicating slave to terminate replication with a
     'different error message on slave and master' error.  (Bug #28244)

   * *Replication*: Binary logging of prepared statements could produce
     syntactically incorrect queries in the binary log, replacing some
     parameters with variable names rather than variable values.  This
     could lead to incorrect results on replication slaves.  (Bug
     #26842, Bug #12826)

   * *Replication*: Connections from one *Note `mysqld': mysqld. server
     to another failed on Mac OS X, affecting replication and
     `FEDERATED' tables.  (Bug #26664) See also Bug #29083.

   * *Replication*: When using transactions and replication, shutting
     down the master in the middle of a transaction would cause all
     slaves to stop replicating.  (Bug #22725)

   * *Replication*: Using *Note `CREATE TABLE LIKE ...': create-table.
     would raise an assertion when replicated to a slave.  (Bug #18950)

   * On the IBM i5 platform, the installation script in the `.savf'
     binaries unconditionally executed the *Note `mysql_install_db':
     mysql-install-db. script. This problem was fixed in a repackaged
     distribution numbered 5.0.44b.  (Bug #30084)

   * Long path names for internal temporary tables could cause stack
     overflows.  (Bug #29015)

   * Using an *Note `INTEGER': numeric-types. column from a table to
     `ROUND()' a number produced different results than using a
     constant with the same value as the *Note `INTEGER':
     numeric-types. column.  (Bug #28980)

   * If a program binds a given number of parameters to a prepared
     statement handle and then somehow changes `stmt->param_count' to a
     different number, *Note `mysql_stmt_execute()':
     mysql-stmt-execute. could crash the client or server.  (Bug #28934)

   * `INSERT .. ON DUPLICATE KEY UPDATE' could under some circumstances
     silently update rows when it should not have.  (Bug #28904)

   * Queries that used `UUID()' were incorrectly permitted into the
     query cache. (This should not happen because `UUID()' is
     nondeterministic.)  (Bug #28897)

   * Using a `VIEW' created with a nonexisting `DEFINER' could lead to
     incorrect results under some circumstances.  (Bug #28895)

   * For `InnoDB' tables that use the `utf8' character set, incorrect
     results could occur for DML statements such as *Note `DELETE':
     delete. or *Note `UPDATE': update. that use an index on
     character-based columns.  (Bug #28878) See also Bug #29449, Bug
     #30485, Bug #31395.

     This regression was introduced by Bug #13195.

   * On Windows, `USE_TLS' was not defined for `mysqlclient.lib'.  (Bug
     #28860)

   * A subquery with `ORDER BY' and `LIMIT 1' could cause a server
     crash.  (Bug #28811)

   * Using `BETWEEN' with nonindexed date columns and short formats of
     the date string could return incorrect results.  (Bug #28778)

   * Selecting `GEOMETRY' columns in a *Note `UNION': union. caused a
     server crash.  (Bug #28763)

   * When constructing the path to the original `.frm' file, `ALTER ..
     RENAME' was unnecessarily (and incorrectly) lowercasing the entire
     path when not on a case-insensitive file system, causing the
     statement to fail.  (Bug #28754)

   * Searches on indexed and nonindexed *Note `ENUM': enum. columns
     could return different results for empty strings.  (Bug #28729)

   * Executing *Note `EXPLAIN EXTENDED': explain. on a query using a
     derived table over a grouping subselect could lead to a server
     crash. This occurred only when materialization of the derived
     tables required creation of an auxiliary temporary table, an
     example being when a grouping operation was carried out with usage
     of a temporary table.  (Bug #28728)

   * The result of evaluation for a view's `CHECK OPTION' option over
     an updated record and records of merged tables was arbitrary and
     dependant on the order of records in the merged tables during the
     execution of the *Note `SELECT': select. statement.  (Bug #28716)

   * The `manager thread' of the LinuxThreads implementation was
     unintentionally started before *Note `mysqld': mysqld. had dropped
     privileges (to run as an unprivileged user). This caused signaling
     between threads in *Note `mysqld': mysqld. to fail when the
     privileges were finally dropped.  (Bug #28690)

   * For debug builds, *Note `ALTER TABLE': alter-table.  could trigger
     an assertion failure due to occurrence of a deadlock when
     committing changes.  (Bug #28652)

   * Killing from one connection a long-running `EXPLAIN QUERY' started
     from another connection caused *Note `mysqld': mysqld. to crash.
     (Bug #28598)

   * Outer join queries with `ON' conditions over constant outer tables
     did not return `NULL'-complemented rows when conditions were
     evaluated to `FALSE'.  (Bug #28571)

   * An update on a multiple-table view with the `CHECK OPTION' clause
     and a subquery in the `WHERE' condition could cause an assertion
     failure.  (Bug #28561)

   * `PURGE MASTER LOGS BEFORE (SUBQUERY)' caused a server crash.
     Subqueries are forbidden in the `BEFORE' clause now.  (Bug #28553)

   * *Note `mysqldump': mysqldump. calculated the required memory for a
     hex-blob string incorrectly causing a buffer overrun. This in turn
     caused *Note `mysqldump': mysqldump. to crash silently and produce
     incomplete output.  (Bug #28522)

   * Passing a *Note `DECIMAL': numeric-types. value as a parameter of
     a statement prepared with *Note `PREPARE': prepare. resulted in an
     error.  (Bug #28509)

   * *Note `mysql_affected_rows()': mysql-affected-rows. could return
     an incorrect result for *Note `INSERT ... ON DUPLICATE KEY
     UPDATE': insert-on-duplicate. if the `CLIENT_FOUND_ROWS' flag was
     set.  (Bug #28505)

   * A query that grouped by the result of an expression returned a
     different result when the expression was assigned to a user
     variable.  (Bug #28494)

   * Subselects returning `LONG' values in MySQL versions later than
     5.0.24a returned `LONGLONG' prior to this. The previous behavior
     was restored.  (Bug #28492) This regression was introduced by Bug
     #19714.

   * Forcing the use of an index on a *Note `SELECT': select. query
     when the index had been disabled would raise an error without
     running the query.  The query now executes, with a warning
     generated noting that the use of a disabled index has been ignored.
     (Bug #28476)

   * The query `SELECT '2007-01-01' + INTERVAL COLUMN_NAME DAY FROM
     TABLE_NAME' caused *Note `mysqld': mysqld. to fail.  (Bug #28450)

   * A server crash could happen under rare conditions such that a
     temporary table outgrew heap memory reserved for it and the
     remaining disk space was not big enough to store the table as a
     `MyISAM' table.  (Bug #28449)

   * *Note `mysql_upgrade': mysql-upgrade. failed if certain SQL modes
     were set. Now it sets the mode itself to avoid this problem.  (Bug
     #28401)

   * The test case for *Note `mysqldump': mysqldump. failed with
     `bin-log' disabled.  (Bug #28372)

   * Attempting to `LOAD_FILE' from an empty floppy drive under
     Windows, caused the server to hang. For example, if you opened a
     connection to the server and then issued the command `SELECT
     LOAD_FILE('a:test');', with no floppy in the drive, the server was
     inaccessible until the modal pop-up dialog box was dismissed.
     (Bug #28366)

   * A buffer overflow could occur when using *Note `DECIMAL':
     numeric-types. columns on Windows operating systems.  (Bug #28361)

   * `libmysql.dll' could not be dynamically loaded on Windows.  (Bug
     #28358)

   * Grouping queries with correlated subqueries in `WHERE' conditions
     could produce incorrect results.  (Bug #28337)

   * `mysqltest' used a too-large stack size on PowerPC/Debian Linux,
     causing thread-creation failure for tests that use many threads.
     (Bug #28333)

   * *Note `EXPLAIN': explain. for a query on an empty table
     immediately after its creation could result in a server crash.
     (Bug #28272)

   * The `IS_UPDATABLE' column in the *Note `INFORMATION_SCHEMA.VIEWS':
     views-table. table was not always set correctly.  (Bug #28266)

   * Comparing a *Note `DATETIME': datetime. column value with a user
     variable yielded incorrect results.  (Bug #28261)

   * For `CAST()' of a `NULL' value with type *Note `DECIMAL':
     numeric-types, the return value was incorrectly initialized,
     producing a runtime error for binaries built using Visual C++ 2005.
     (Bug #28250)

   * Portability problems caused by use of `isinf()' were corrected.
     (Bug #28240)

   * When dumping procedures, *Note `mysqldump `--compact' ':
     mysqldump. generated output that restored the session variable
     `sql_mode' without first capturing it. When dumping routines,
     *Note `mysqldump `--compact' ': mysqldump. neither set nor
     retrieved the value of `sql_mode'.  (Bug #28223)

   * Comparison of the string value of a date showed as unequal to
     `CURTIME()'. Similar behavior was exhibited for *Note `DATETIME':
     datetime. values.  (Bug #28208)

   * The `Bytes_received' and `Bytes_sent' status variables could hold
     only 32-bit values (not 64-bit values) on some platforms.  (Bug
     #28149)

   * Storing a large number into a *Note `FLOAT': numeric-types. or
     *Note `DOUBLE': numeric-types. column with a fixed length could
     result in incorrect truncation of the number if the column's
     length was greater than 31.  (Bug #28121)

   * *Note `DECIMAL': numeric-types. values beginning with nine `9'
     digits could be incorrectly rounded.  (Bug #27984)

   * The second execution of a prepared statement from a *Note `UNION':
     union. query with `ORDER BY RAND()' caused the server to crash.
     This problem could also occur when invoking a stored procedure
     containing such a query.  (Bug #27937)

   * For attempts to open a nonexistent table, the server should report
     `ER_NO_SUCH_TABLE' but sometimes reported `ER_TABLE_NOT_LOCKED'.
     (Bug #27907)

   * A stored program that uses a variable name containing multibyte
     characters could fail to execute.  (Bug #27876)

   * `ON' conditions from `JOIN' expressions were ignored when checking
     the `CHECK OPTION' clause while updating a multiple-table view
     that included such a clause.  (Bug #27827)

   * On some systems, `udf_example.c' returned an incorrect result
     length. Also on some systems, `mysql-test-run.pl' could not find
     the shared object built from `udf_example.c'.  (Bug #27741)

   * `HASH' indexes on *Note `VARCHAR': char. columns with binary
     collations did not ignore trailing spaces from strings before
     comparisons. This could result in duplicate records being
     successfully inserted into a `MEMORY' table with unique key
     constraints. A consequence was that internal `MEMORY' tables used
     for `GROUP BY' calculation contained duplicate rows that resulted
     in duplicate-key errors when converting those temporary tables to
     `MyISAM', and that error was incorrectly reported as a `table is
     full' error.  (Bug #27643)

   * An error occurred trying to connect to *Note `mysqld-debug.exe':
     mysqld.  (Bug #27597)

   * Selecting `MIN()' on an indexed column that contained only `NULL'
     values caused `NULL' to be returned for other result columns.
     (Bug #27573)

   * If a stored function or trigger was killed, it aborted but no
     error was thrown, permitting the calling statement to continue
     without noticing the problem. This could lead to incorrect results.
     (Bug #27563)

   * When *Note `ALTER TABLE': alter-table. was used to add a new *Note
     `DATE': datetime. column with no explicit default value,
     `'0000-00-00'' was used as the default even if the SQL mode
     included the `NO_ZERO_DATE' mode to prohibit that value. A similar
     problem occurred for *Note `DATETIME': datetime. columns.  (Bug
     #27507)

   * Using a *Note `TEXT': blob. local variable in a stored routine in
     an expression such as `SET VAR = SUBSTRING(VAR, 3)' produced an
     incorrect result.  (Bug #27415)

   * The error message for error number `137' did not report which
     database/table combination reported the problem.  (Bug #27173)

   * A large filesort could result in a division by zero error and a
     server crash.  (Bug #27119)

   * Some test suite files were missing from some MySQL-test packages.
     (Bug #26609)

   * Statements within triggers ignored the value of the
     `low_priority_updates' system variable.  (Bug #26162) See also Bug
     #29963.

   * Running *Note `CHECK TABLE': check-table. concurrently with a
     *Note `SELECT': select, *Note `INSERT': insert. or other statement
     on Windows could corrupt a MyISAM table.  (Bug #25712)

   * On Windows, connection handlers did not properly decrement the
     server's thread count when exiting.  (Bug #25621)

   * Due to a race condition, executing *Note `FLUSH PRIVILEGES':
     flush. in one thread could cause brief table unavailability in
     other threads.  (Bug #24988)

   * When *Note `mysqld': mysqld. was run as a Windows service, shared
     memory objects were not created in the global namespace and could
     not be used by clients to connect.  (Bug #24731)

   * On some Linux distributions where LinuxThreads and NPTL `glibc'
     versions both are available, statically built binaries can crash
     because the linker defaults to LinuxThreads when linking
     statically, but calls to external libraries (such as `libnss') are
     resolved to NPTL versions. This cannot be worked around in the
     code, so instead if a crash occurs on such a binary/OS
     combination, print an error message that provides advice about how
     to fix the problem.  (Bug #24611)

   * Implicit conversion of `9912101' to *Note `DATE': datetime. did
     not match `CAST(9912101 AS DATE)'.  (Bug #23093)

   * Conversion errors could occur when constructing the condition for
     an `IN' predicate. The predicate was treated as if the affected
     column contains `NULL', but if the `IN' predicate is inside `NOT',
     incorrect results could be returned.  (Bug #22855)

   * Linux binaries were unable to dump core after executing a
     `setuid()' call.  (Bug #21723)

   * Stack overflow caused server crashes.  (Bug #21476)

   * `CURDATE()' is less than `NOW()', either when comparing
     `CURDATE()' directly (`CURDATE() < NOW()' is true) or when casting
     `CURDATE()' to *Note `DATE': datetime. (`CAST(CURDATE() AS DATE) <
     NOW()' is true). However, storing `CURDATE()' in a *Note `DATE':
     datetime. column and comparing `COL_NAME < NOW()' incorrectly
     yielded false. This is fixed by comparing a *Note `DATE':
     datetime. column as *Note `DATETIME': datetime. for comparisons to
     a *Note `DATETIME': datetime. constant.  (Bug #21103)

   * For dates with 4-digit year parts less than 200, an incorrect
     implicit conversion to add a century was applied for date
     arithmetic performed with `DATE_ADD()', `DATE_SUB()', `+
     INTERVAL', and `- INTERVAL'. (For example, `DATE_ADD('0050-01-01
     00:00:00', INTERVAL 0 SECOND)' became `'2050-01-01 00:00:00''.)
     (Bug #18997)

   * Granting access privileges to an individual table where the
     database or table name contained an underscore would fail.  (Bug
     #18660)

   * The `-lmtmalloc' library was removed from the output of *Note
     `mysql_config': mysql-config. on Solaris, as it caused problems
     when building `DBD::mysql' (and possibly other applications) on
     that platform that tried to use `dlopen()' to access the client
     library.  (Bug #18322)

   * The `check-cpu' script failed to detect AMD64 Turion processors
     correctly.  (Bug #17707)

   * Trying to shut down the server following a failed *Note `LOAD DATA
     INFILE': load-data. caused *Note `mysqld': mysqld. to crash.  (Bug
     #17233)

   * Using up-arrow for command-line recall in *Note `mysql': mysql.
     could cause a segmentation fault.  (Bug #10218)

   * The result for `CAST()' when casting a value to `UNSIGNED' was
     limited to the maximum signed *Note `BIGINT': numeric-types. value
     (9223372036854775808), rather than the maximum unsigned value
     (18446744073709551615).  (Bug #8663)


File: manual.info,  Node: news-5-0-42,  Next: news-5-0-41,  Prev: news-5-0-44,  Up: news-5-0-x

D.1.55 Changes in MySQL Enterprise 5.0.42 [MRU] (23 May 2007)
-------------------------------------------------------------

This is a _Monthly Rapid Update_ release of the MySQL Enterprise Server
5.0.

This section documents all changes and bug fixes that have been applied
since the last MySQL Enterprise Server release (5.0.40).

*Functionality Added or Changed*

   * *Incompatible Change*: Prior to this release, when *Note `DATE':
     datetime.  values were compared with *Note `DATETIME': datetime.
     values, the time portion of the *Note `DATETIME': datetime. value
     was ignored, or the comparison could be performed as a string
     compare. Now a *Note `DATE': datetime. value is coerced to the
     *Note `DATETIME': datetime. type by adding the time portion as
     `00:00:00'. To mimic the old behavior, use the `CAST()' function
     as shown in this example: `SELECT DATE_COL = CAST(NOW() AS DATE)
     FROM TABLE;'.  (Bug #28929)

   * *Incompatible Change*: *Note `INSERT DELAYED': insert-delayed. is
     now downgraded to a normal *Note `INSERT': insert. if the
     statement uses functions that access tables or triggers, or that
     is called from a function or a trigger.

     This was done to resolve the following interrelated issues:

        * The server could abort or deadlock for *Note `INSERT
          DELAYED': insert-delayed. statements for which another insert
          was performed implicitly (for example, using a stored
          function that inserted a row).

        * A trigger using an *Note `INSERT DELAYED': insert-delayed.
          caused the error `INSERT DELAYED can't be used with table ...
          because it is locked with LOCK TABLES' although the target
          table was not actually locked.

        * *Note `INSERT DELAYED': insert-delayed. into a table with a
          `BEFORE INSERT' or `AFTER INSERT' trigger gave an incorrect
          `NEW' pseudocolumn value and caused the server to deadlock or
          abort.

     (Bug #21483) See also Bug #20497, Bug #21714.

   * *Note `mysqld_multi': mysqld-multi. now understands the
     `--no-defaults', `--defaults-file', and `--defaults-extra-file'
     options. The `--config-file' option is deprecated; if given, it is
     treated like `--defaults-extra-file'.  (Bug #27390)

*Bugs Fixed*

   * *Security Fix*: Use of a view could enable a user to gain update
     privileges for tables in other databases.  (Bug #27878,
     CVE-2007-3782)

   * *Security Fix*: The requirement of the `DROP' privilege for *Note
     `RENAME TABLE': rename-table. was not enforced.  (Bug #27515,
     CVE-2007-2691)

   * *Security Fix*: If a stored routine was declared using `SQL
     SECURITY INVOKER', a user who invoked the routine could gain
     privileges.  (Bug #27337, CVE-2007-2692)

   * *MySQL Cluster*: The cluster waited 30 seconds instead of 30
     milliseconds before reading table statistics.  (Bug #28093)

   * *MySQL Cluster*: *Note `INSERT IGNORE': insert.  wrongly ignored
     `NULL' values in unique indexes.  (Bug #27980)

   * *MySQL Cluster*: The name of the month `March' was given
     incorrectly in the cluster error log.  (Bug #27926)

   * *MySQL Cluster*: It was not possible to add a unique index to an
     *Note `NDB': mysql-cluster. table while in single user mode.  (Bug
     #27710)

   * *MySQL Cluster*: Repeated insertion of data generated by *Note
     `mysqldump': mysqldump. into *Note `NDB': mysql-cluster. tables
     could eventually lead to failure of the cluster.  (Bug #27437)

   * *MySQL Cluster*: `ndb_connectstring' did not appear in the output
     of *Note `SHOW VARIABLES': show-variables.  (Bug #26675)

   * *Replication*: Aborting a statement on the master that applied to a
     nontransactional statement broke replication. The statement was
     written to the binary log but not completely executed on the
     master. Slaves receiving the statement executed it completely,
     resulting in loss of data synchrony. Now an error code is written
     to the error log so that the slaves stop without executing the
     aborted statement. (That is, replication stops, but synchrony to
     the point of the stop is preserved and you can investigate the
     problem.)  (Bug #26551)

   * *Replication*: Restoration of the default database after stored
     routine or trigger execution on a slave could cause replication to
     stop if the database no longer existed.  (Bug #25082)

   * *Cluster API*: For *Note `BLOB': blob. reads on operations with
     lock mode `LM_CommittedRead', the lock mode was not upgraded to
     `LM_Read' before the state of the *Note `BLOB': blob. had already
     been calculated. The *Note `NDB': mysql-cluster. API methods
     affected by this problem included the following:

        * `NdbOperation::readTuple()'

        * `NdbScanOperation::readTuples()'

        * `NdbIndexScanOperation::readTuples()'

     (Bug #27320)

   * On the IBM i5 platform, the installation script in the `.savf'
     binaries unconditionally executed the *Note `mysql_install_db':
     mysql-install-db. script. This problem was fixed in a repackaged
     distribution numbered 5.0.42b.  (Bug #30084)

   * A query with a `NOT IN' subquery predicate could cause a crash
     when the left operand of the predicate evaluated to `NULL'.  (Bug
     #28375)

   * For `InnoDB', in some rare cases the optimizer preferred a more
     expensive `ref' access to a less expensive range access.  (Bug
     #28189)

   * A performance degradation was observed for outer join queries to
     which a not-exists optimization was applied.  (Bug #28188)

   * `SELECT * INTO OUTFILE ... FROM INFORMATION_SCHEMA.SCHEMATA'
     failed with an `Access denied' error, even for a user who had the
     `FILE' privilege.  (Bug #28181)

   * Comparisons of *Note `DATE': datetime. or *Note `DATETIME':
     datetime. values for the `IN()' function could yield incorrect
     results.  (Bug #28133)

   * The server could hang for `INSERT IGNORE ... ON DUPLICATE KEY
     UPDATE' if an update failed.  (Bug #28000)

   * `CAST()' to *Note `DECIMAL': numeric-types. did not check for
     overflow.  (Bug #27957)

   * For *Note `INSERT ... ON DUPLICATE KEY UPDATE':
     insert-on-duplicate. statements that affected many rows, updates
     could be applied to the wrong rows.  (Bug #27954)

   * Early `NULL'-filtering optimization did not work for `eq_ref'
     table access.  (Bug #27939)

   * Views ignored precision for `CAST()' operations.  (Bug #27921)

   * Nongrouped columns were permitted by `*' in `ONLY_FULL_GROUP_BY'
     SQL mode.  (Bug #27874)

   * Debug builds on Windows generated false alarms about uninitialized
     variables with some Visual Studio runtime libraries.  (Bug #27811)

   * Certain queries that used uncorrelated scalar subqueries caused
     *Note `EXPLAIN': explain. to crash.  (Bug #27807)

   * Changes to some system variables should invalidate statements in
     the query cache, but invalidation did not happen.  (Bug #27792)

   * Performing a *Note `UNION': union. on two views that had `ORDER
     BY' clauses resulted in an `Unknown column' error.  (Bug #27786)

   * *Note `mysql_install_db': mysql-install-db. is supposed to detect
     existing system tables and create only those that do not exist.
     Instead, it was exiting with an error if tables already existed.
     (Bug #27783)

   * *Note `mysqld': mysqld. did not check the length of option values
     and could crash with a buffer overflow for long values.  (Bug
     #27715)

   * Comparisons using row constructors could fail for rows containing
     `NULL' values.  (Bug #27704)

   * *Note `LOAD DATA': load-data. did not use `CURRENT_TIMESTAMP' as
     the default value for a *Note `TIMESTAMP': datetime. column for
     which no value was provided.  (Bug #27670)

   * *Note `mysqldump': mysqldump. could not connect using SSL.  (Bug
     #27669)

   * On Linux, the server could not create temporary tables if
     `lower_case_table_names' was set to 1 and the value of `tmpdir'
     was a directory name containing any uppercase letters.  (Bug
     #27653)

   * For `InnoDB' tables, a multiple-row *Note `INSERT': insert. of the
     form `INSERT INTO t (id...) VALUES (NULL...) ON DUPLICATE KEY
     UPDATE id=VALUES(id)', where `id' is an `AUTO_INCREMENT' column,
     could cause `ERROR 1062 (23000): Duplicate entry...' errors or
     lost rows.  (Bug #27650)

   * The XML output representing an empty result was an empty string
     rather than an empty `<resultset/>' element.  (Bug #27608)

   * Comparison of a *Note `DATE': datetime. with a *Note `DATETIME':
     datetime. did not treat the *Note `DATE': datetime. as having a
     time part of `00:00:00'.  (Bug #27590) See also Bug #32198.

   * The fix for Bug #17212 provided correct sort order for misordered
     output of certain queries, but caused significant overall query
     performance degradation. (Results were correct (good), but
     returned much more slowly (bad).) The fix also affected
     performance of queries for which results were correct.  The
     performance degradation has been addressed.  (Bug #27531)

   * The `CRC32()' function returns an unsigned integer, but the
     metadata was signed, which could cause certain queries to return
     incorrect results. (For example, queries that selected a `CRC32()'
     value and used that value in the `GROUP BY' clause.)  (Bug #27530)

   * An interaction between *Note `SHOW TABLE STATUS':
     show-table-status. and other concurrent statements that modify the
     table could result in a divide-by-zero error and a server crash.
     (Bug #27516)

   * A race condition between *Note `DROP TABLE': drop-table. and *Note
     `SHOW TABLE STATUS': show-table-status. could cause the latter to
     display incorrect information.  (Bug #27499)

   * Nested aggregate functions could be improperly evaluated.  (Bug
     #27363)

   * A stored function invocation in the `WHERE' clause was treated as
     a constant.  (Bug #27354)

   * Failure to allocate memory associated with
     `transaction_prealloc_size' could cause a server crash.  (Bug
     #27322)

   * *Note `mysqldump': mysqldump. crashed if it got no data from *Note
     `SHOW CREATE PROCEDURE': show-create-procedure. (for example, when
     trying to dump a routine defined by a different user and for which
     the current user had no privileges). Now it prints a comment to
     indicate the problem. It also returns an error, or continues if
     the `--force' option is given.  (Bug #27293)

   * *Note `mysqlbinlog': mysqlbinlog. produced different output with
     the `-R' option than without it.  (Bug #27171)

   * Flow control optimization in stored routines could cause exception
     handlers to never return or execute incorrect logic.  (Bug #26977)

   * *Note `mysqldump': mysqldump. would not dump a view for which the
     `DEFINER' no longer exists.  (Bug #26817)

   * Creating a temporary table with `InnoDB' when using the
     one-file-per-table setting, and when the host file system for
     temporary tables was `tmpfs', would cause an assertion within
     `mysqld'. This was due to the use of `O_DIRECT' when opening the
     temporary table file.  (Bug #26662)

   * *Note `mysql_upgrade': mysql-upgrade. did not detect failure of
     external commands that it runs.  (Bug #26639)

   * Index hints (`USE INDEX', `IGNORE INDEX', `FORCE INDEX') cannot be
     used with `FULLTEXT' indexes, but were not being ignored.  (Bug
     #25951)

   * If *Note `CREATE TABLE t1 LIKE t2': create-table. failed due to a
     full disk, an empty `t2.frm' file could be created but not
     removed. This file then caused subsequent attempts to create a
     table named `t2' to fail. This is easily corrected at the file
     system level by removing the `t2.frm' file manually, but now the
     server removes the file if the create operation does not complete
     successfully.  (Bug #25761)

   * *Note `mysql_upgrade': mysql-upgrade. did not pass a password to
     *Note `mysqlcheck': mysqlcheck. if one was given.  (Bug #25452)

   * On Windows, *Note `mysql_upgrade': mysql-upgrade. was sensitive to
     lettercase of the names of some required components.  (Bug #25405)

   * For storage engines that permit the current auto-increment value
     to be set, using `ALTER TABLE ... ENGINE' to convert a table from
     one such storage engine to another caused loss of the current
     value. (For storage engines that do not support setting the value,
     it cannot be retained anyway when changing the storage engine.)
     (Bug #25262)

   * Several math functions produced incorrect results for large
     unsigned values. `ROUND()' produced incorrect results or a crash
     for a large number-of-decimals argument.  (Bug #24912)

   * The result set of a query that used `WITH ROLLUP' and `DISTINCT'
     could lack some rollup rows (rows with `NULL' values for grouping
     attributes) if the `GROUP BY' list contained constant expressions.
     (Bug #24856)

   * For queries that used `ORDER BY' with `InnoDB' tables, if the
     optimizer chose an index for accessing the table but found a
     covering index that enabled the `ORDER BY' to be skipped, no
     results were returned.  (Bug #24778)

   * Concurrent execution of *Note `CREATE TABLE ... SELECT':
     create-table. and other statements involving the target table
     suffered from various race conditions, some of which might have
     led to deadlocks.  (Bug #24738)

   * An attempt to execute *Note `CREATE TABLE ... SELECT':
     create-table. when a temporary table with the same name already
     existed led to the insertion of data into the temporary table and
     creation of an empty nontemporary table.  (Bug #24508)

   * The `MERGE' storage engine could return incorrect results when
     several index values that compare equality were present in an
     index (for example, `'gross'' and `'gross '', which are considered
     equal but have different lengths).  (Bug #24342)

   * Some upgrade problems are detected and better error messages
     suggesting that *Note `mysql_upgrade': mysql-upgrade. be run are
     produced.  (Bug #24248)

   * Some views could not be created even when the user had the
     requisite privileges.  (Bug #24040)

   * Using `CAST()' to convert *Note `DATETIME': datetime. values to
     numeric values did not work.  (Bug #23656)

   * The `AUTO_INCREMENT' value would not be correctly reported for
     `InnoDB' tables when using *Note `SHOW CREATE TABLE':
     show-create-table. statement or *Note `mysqldump': mysqldump.
     command.  (Bug #23313)

   * `SELECT COUNT(*)' from a table containing a `DATETIME NOT NULL'
     column could produce spurious warnings with the `NO_ZERO_DATE' SQL
     mode enabled.  (Bug #22824)

   * Using *Note `SET GLOBAL': set-option. to change the
     `lc_time_names' system variable had no effect on new connections.
     (Bug #22648)

   * A multiple-table *Note `UPDATE': update. could return an incorrect
     rows-matched value if, during insertion of rows into a temporary
     table, the table had to be converted from a `MEMORY' table to a
     `MyISAM' table.  (Bug #22364)

   * yaSSL crashed on pre-Pentium Intel CPUs.  (Bug #21765)

   * A slave that used `--master-ssl-cipher' could not connect to the
     master.  (Bug #21611)

   * Quoted labels in stored routines were mishandled, rendering the
     routines unusable.  (Bug #21513)

   * *Note `CREATE TABLE IF NOT EXISTS ... SELECT':
     create-table-select. caused a server crash if the target table
     already existed and had a `BEFORE INSERT' trigger.  (Bug #20903)

   * Deadlock occurred for attempts to execute *Note `CREATE TABLE IF
     NOT EXISTS ... SELECT': create-table-select. when *Note `LOCK
     TABLES': lock-tables. had been used to acquire a read lock on the
     target table.  (Bug #20662, Bug #15522)

   * Changing a `utf8' column in an `InnoDB' table to a shorter length
     did not shorten the data values.  (Bug #20095)

   * The omission of leading zeros in dates could lead to erroneous
     results when these were compared with the output of certain date
     and time functions.  (Bug #16377)

   * `INSERT...ON DUPLICATE KEY UPDATE' could cause `Error 1032: Can't
     find record in ...' for inserts into an `InnoDB' table unique index
     using key column prefixes with an underlying `utf8' string column.
     (Bug #13191)

   * Having the `EXECUTE' privilege for a routine in a database should
     make it possible to *Note `USE': use. that database, but the server
     returned an error instead. This has been corrected. As a result of
     the change, *Note `SHOW TABLES': show-tables. for a database in
     which you have only the `EXECUTE' privilege returns an empty set
     rather than an error.  (Bug #9504)


File: manual.info,  Node: news-5-0-41,  Next: news-5-0-40,  Prev: news-5-0-42,  Up: news-5-0-x

D.1.56 Changes in MySQL Community Server 5.0.41 (01 May 2007)
-------------------------------------------------------------

This is a bugfix release for the current MySQL Community Server
production release family. It replaces MySQL 5.0.37.

*Functionality Added or Changed*

   * If a set function S with an outer reference ` S(OUTER_REF)' cannot
     be aggregated in the outer query against which the outer reference
     has been resolved, MySQL interprets ` S(OUTER_REF)' the same way
     that it would interpret ` S(CONST)'.  However, standard SQL
     requires throwing an error in this situation. An error now is
     thrown for such queries if the `ANSI' SQL mode is enabled.  (Bug
     #27348)

   * Prefix lengths for columns in `SPATIAL' indexes are no longer
     displayed in *Note `SHOW CREATE TABLE': show-create-table. output.
     *Note `mysqldump': mysqldump. uses that statement, so if a table
     with `SPATIAL' indexes containing prefixed columns is dumped and
     reloaded, the index is created with no prefixes. (The full column
     width of each column is indexed.)  (Bug #26794)

   * The output of *Note `mysql': mysql.  `--xml' and *Note
     `mysqldump': mysqldump.  `--xml' now includes a valid XML
     namespace.  (Bug #25946)

   * If you use SSL for a client connection, you can tell the client
     not to authenticate the server certificate by specifying neither
     `--ssl-ca' nor `--ssl-capath'. The server still verifies the
     client according to any applicable requirements established using
     *Note `GRANT': grant.  statements for the client, and it still
     uses any `--ssl-ca'/`--ssl-capath' values that were passed to
     server at startup time.  (Bug #25309)

   * The server now includes a timestamp in error messages that are
     logged as a result of unhandled signals (such as `mysqld got
     signal 11' messages).  (Bug #24878)

   * The syntax for index hints has been extended to enable explicit
     specification that the hint applies only to join processing. See
     *Note index-hints::.

     This is a new fix for this issue, and replaces the fix made in
     MySQL 5.0.25 and reverted in 5.0.26.  (Bug #21174)

   * Added the `--secure-file-priv' option for *Note `mysqld': mysqld,
     which limits the effect of the `LOAD_FILE()' function and the
     *Note `LOAD DATA': load-data. and *Note `SELECT ... INTO OUTFILE':
     select. statements to work only with files in a given directory.
     (Bug #18628)

   * Binary distributions for some platforms did not include shared
     libraries; now shared libraries are shipped for all platforms
     except AIX 5.2 64-bit. _Exception_: The library for the
     `libmysqld' embedded server is not shared except on Windows.  (Bug
     #16520, Bug #26767, Bug #13450)

   * Added the read-only `hostname' system variable, which the server
     sets at startup to the server host name.

   * The `mysql_create_system_tables' script was removed because *Note
     `mysql_install_db': mysql-install-db. no longer uses it in MySQL
     5.0.

   * To satisfy different user requirements, we provide several
     servers. *Note `mysqld': mysqld. is an optimized server that is a
     smaller, faster binary. Each package now also includes *Note
     `mysqld-debug': mysqld, which is compiled with debugging support
     but is otherwise configured identically to the nondebug server.

*Bugs Fixed*

   * *Incompatible Change*: *Note `INSERT DELAYED': insert-delayed.
     statements are not supported for `MERGE' tables, but the `MERGE'
     storage engine was not rejecting such statements, resulting in
     table corruption. Applications previously using *Note `INSERT
     DELAYED': insert-delayed.  into `MERGE' table will break when
     upgrading to versions with this fix. To avoid the problem, remove
     `DELAYED' from such statements.  (Bug #26464)

   * *MySQL Cluster*: *Note `NDB': mysql-cluster. tables having
     `MEDIUMINT AUTO_INCREMENT' columns were not restored correctly by
     *Note `ndb_restore': mysql-cluster-programs-ndb-restore, causing
     spurious duplicate key errors. This issue did not affect *Note
     `TINYINT': numeric-types, *Note `INT': numeric-types, or *Note
     `BIGINT': numeric-types. columns with `AUTO_INCREMENT'.  (Bug
     #27775)

   * *MySQL Cluster*: *Note `NDB': mysql-cluster. tables with indexes
     whose names contained space characters were not restored correctly
     by *Note `ndb_restore': mysql-cluster-programs-ndb-restore. (the
     index names were truncated).  (Bug #27758)

   * *MySQL Cluster*: Under certain rare circumstances performing a
     *Note `DROP TABLE': drop-table. or *Note `TRUNCATE TABLE':
     truncate-table. on an *Note `NDB': mysql-cluster. table could
     cause a node failure or forced cluster shutdown.  (Bug #27581)

   * *MySQL Cluster*: Memory usage of a *Note `mysqld': mysqld. process
     grew even while idle.  (Bug #27560)

   * *MySQL Cluster*: It was not possible to set `LockPagesInMainMemory'
     equal to `0'.  (Bug #27291)

   * *MySQL Cluster*: A race condition could sometimes occur if the
     node acting as master failed while node IDs were still being
     allocated during startup.  (Bug #27286)

   * *MySQL Cluster*: When a data node was taking over as the master
     node, a race condition could sometimes occur as the node was
     assuming responsibility for handling of global checkpoints.  (Bug
     #27283)

   * *MySQL Cluster*: Error messages displayed when running in single
     user mode were inconsistent.  (Bug #27021)

   * *MySQL Cluster*: The failure of a data node while restarting could
     cause other data nodes to hang or crash.  (Bug #27003)

   * *MySQL Cluster*: On Solaris, the value of an *Note `NDB':
     mysql-cluster.  table column declared as `BIT(33)' was always
     displayed as `0'.  (Bug #26986)

   * *MySQL Cluster*: *Note `mysqld': mysqld. processes would sometimes
     crash under high load.  (Bug #26825)

   * *MySQL Cluster*: The output from *Note `ndb_restore
     `--print_data'': mysql-cluster-programs-ndb-restore. was incorrect
     for a backup made of a database containing tables with *Note
     `TINYINT': numeric-types. or *Note `SMALLINT': numeric-types.
     columns.  (Bug #26740)

   * *MySQL Cluster*: An inadvertent use of unaligned data caused *Note
     `ndb_restore': mysql-cluster-programs-ndb-restore. to fail on some
     64-bit platforms, including Sparc and Itanium-2.  (Bug #26739)

   * *MySQL Cluster*: An invalid pointer was returned following a
     `FSCLOSECONF' signal when accessing the REDO logs during a node
     restart or system restart.  (Bug #26515)

   * *MySQL Cluster*: The failure of a data node when restarting it with
     `--initial' could lead to failures of subsequent data node
     restarts.  (Bug #26481)

   * *MySQL Cluster*: Takeover for local checkpointing due to multiple
     failures of master nodes was sometimes incorrectly handled.  (Bug
     #26457)

   * *MySQL Cluster*: The `LockPagesInMainMemory' parameter was not
     read until after distributed communication had already started
     between cluster nodes. When the value of this parameter was `1',
     this could sometimes result in data node failure due to missed
     heartbeats.  (Bug #26454)

   * *MySQL Cluster*: Under some circumstances, following the restart
     of a management node, all data nodes would connect to it normally,
     but some of them subsequently failed to log any events to the
     management node.  (Bug #26293)

   * *MySQL Cluster*: In some cases, `AFTER UPDATE' and `AFTER DELETE'
     triggers on *Note `NDB': mysql-cluster. tables that referenced
     subject table did not see the results of operation which caused
     invocation of the trigger, but rather saw the row as it was prior
     to the update or delete operation.

     This was most noticeable when an update operation used a subquery
     to obtain the rows to be updated. An example would be `UPDATE tbl1
     SET col2 = val1 WHERE tbl1.col1 IN (SELECT col3 FROM tbl2 WHERE c4
     = val2)' where there was an `AFTER UPDATE' trigger on table
     `tbl1'. In such cases, the trigger would fail to execute.

     The problem occurred because the actual update or delete
     operations were deferred to be able to perform them later as one
     batch. The fix for this bug solves the problem by disabling this
     optimization for a given update or delete if the table has an
     `AFTER' trigger defined for this operation.  (Bug #26242)

   * *MySQL Cluster*: Condition pushdown did not work with prepared
     statements.  (Bug #26225)

   * *MySQL Cluster*: Joins on multiple tables containing *Note `BLOB':
     blob. columns could cause data nodes run out of memory, and to
     crash with the error `NdbObjectIdMap::expand unable to expand'.
     (Bug #26176)

   * *MySQL Cluster*: After entering single user mode it was not
     possible to alter non-*Note `NDB': mysql-cluster. tables on any
     SQL nodes other than the one having sole access to the cluster.
     (Bug #25275)

   * *MySQL Cluster*: The management client command ` NODE_ID STATUS'
     displayed the message `Node NODE_ID: not connected' when NODE_ID
     was not the node ID of a data node.

     *Note*:

     The `ALL STATUS' command in the cluster management client still
     displays status information for data nodes only. This is by
     design. See *Note mysql-cluster-mgm-client-commands::, for more
     information.

     (Bug #21715)

   * *MySQL Cluster*: The message `Error 0 in readAutoIncrementValue():
     no Error' was written to the error log whenever *Note `SHOW TABLE
     STATUS': show-table-status. was performed on a Cluster table that
     did not have an `AUTO_INCREMENT' column.  (Bug #21033)

   * *MySQL Cluster*: Some values of `MaxNoOfTables' caused the error
     `Job buffer congestion' to occur.  (Bug #19378)

   * *Replication*: Out-of-memory errors were not reported. Now they
     are written to the error log.  (Bug #26844)

   * *Replication*: Improved out-of-memory detection when sending logs
     from a master server to slaves, and log a message when allocation
     fails.  (Bug #26837)

   * *Replication*: A multiple-row delayed insert with an
     auto-increment column could cause duplicate entries to be created
     on the slave in a replication environment.  (Bug #26116, Bug
     #25507)

   * *Replication*: When `RAND()' was called multiple times inside a
     stored procedure, the server did not write the correct random seed
     values to the binary log, resulting in incorrect replication.
     (Bug #25543)

   * *Replication*: *Note `GRANT': grant. statements were not
     replicated if the server was started with the
     `--replicate-ignore-table' or `--replicate-wild-ignore-table'
     option.  (Bug #25482)

   * *Replication*: Duplicating the usage of a user variable in a
     stored procedure or trigger would not be replicated correctly to
     the slave.  (Bug #25167)

   * *Replication*: *Note `DROP TRIGGER': drop-trigger. statements
     would not be filtered on the slave when using the
     `replication-wild-do-table' option.  (Bug #24478)

   * *Replication*: For *Note `INSERT ... ON DUPLICATE KEY UPDATE':
     insert-on-duplicate. statements where some `AUTO_INCREMENT' values
     were generated automatically for inserts and some rows were
     updated, one auto-generated value was lost per updated row,
     leading to faster exhaustion of the range of the `AUTO_INCREMENT'
     column.

     Because the original problem can affect replication (different
     values on master and slave), it is recommended that the master and
     its slaves be upgraded to the current version.  (Bug #24432)

   * *Replication*: Replication between master and slave would
     infinitely retry binary log transmission where the
     `max_allowed_packet' on the master was larger than that on the
     slave if the size of the transfer was between these two values.
     (Bug #23775)

   * *Replication*: Loading data using *Note `LOAD DATA INFILE':
     load-data. may not replicate correctly (due to character set
     incompatibilities) if the `character_set_database' variable is set
     before the data is loaded.  (Bug #15126)

   * *Replication*: User defined variables used within stored
     procedures and triggers are not replicated correctly when
     operating in statement-based replication mode.  (Bug #14914, Bug
     #20141)

   * *Cluster Replication*: Some queries that updated multiple tables
     were not backed up correctly.  (Bug #27748)

   * *Cluster API*: Using `NdbBlob::writeData()' to write data in the
     middle of an existing blob value (that is, updating the value)
     could overwrite some data past the end of the data to be changed.
     (Bug #27018)

   * Some equi-joins containing a `WHERE' clause that included a `NOT
     IN' subquery caused a server crash.  (Bug #27870)

   * *Note `SELECT DISTINCT': select. could return incorrect results if
     the select list contained duplicated columns.  (Bug #27659)

   * With `NO_AUTO_VALUE_ON_ZERO' SQL mode enabled, *Note `LOAD DATA':
     load-data.  operations could assign incorrect `AUTO_INCREMENT'
     values.  (Bug #27586)

   * Incorrect results could be returned for some queries that
     contained a select list expression with `IN' or `BETWEEN' together
     with an `ORDER BY' or `GROUP BY' on the same expression using `NOT
     IN' or `NOT BETWEEN'.  (Bug #27532)

   * Evaluation of an `IN()' predicate containing a decimal-valued
     argument caused a server crash.  (Bug #27513, Bug #27362,
     CVE-2007-2583)

   * Profiling overhead was incurred even with profiling disabled.
     (Bug #27501)

   * In out-of-memory conditions, the server might crash or otherwise
     not report an error to the Windows event log.  (Bug #27490)

   * Passing nested row expressions with different structures to an
     `IN' predicate caused a server crash.  (Bug #27484)

   * The `decimal.h' header file was incorrectly omitted from binary
     distributions.  (Bug #27456)

   * With `innodb_file_per_table' enabled, attempting to rename an
     `InnoDB' table to a nonexistent database caused the server to exit.
     (Bug #27381)

   * A subquery could get incorrect values for references to outer
     query columns when it contained aggregate functions that were
     aggregated in outer context.  (Bug #27321)

   * In a view, a column that was defined using a `GEOMETRY' function
     was treated as having the *Note `LONGBLOB': blob. data type rather
     than the `GEOMETRY' type.  (Bug #27300)

   * Queries containing subqueries with `COUNT(*)' aggregated in an
     outer context returned incorrect results. This happened only if the
     subquery did not contain any references to outer columns.  (Bug
     #27257)

   * *Note `SELECT ... INTO OUTFILE': select. with a long `FIELDS
     ENCLOSED BY' value could crash the server.  (Bug #27231)

   * Use of an aggregate function from an outer context as an argument
     to `GROUP_CONCAT()' caused a server crash.  (Bug #27229)

   * String truncation upon insertion into an integer or year column
     did not generate a warning (or an error in strict mode).  (Bug
     #27176, Bug #26359)

   * Storing `NULL' values in spatial fields caused excessive memory
     allocation and crashes on some systems.  (Bug #27164)

   * Row equalities in `WHERE' clauses could cause memory corruption.
     (Bug #27154)

   * `GROUP BY' on a `ucs2' column caused a server crash when there was
     at least one empty string in the column.  (Bug #27079)

   * Duplicate members in *Note `SET': set. or *Note `ENUM': enum.
     definitions were not detected. Now they result in a warning; if
     strict SQL mode is enabled, an error occurs instead.  (Bug #27069)

   * For *Note `INSERT ... ON DUPLICATE KEY UPDATE':
     insert-on-duplicate. statements on tables containing
     `AUTO_INCREMENT' columns, `LAST_INSERT_ID()' was reset to 0 if no
     rows were successfully inserted or changed. `Not changed' includes
     the case where a row was updated to its current values, but in
     that case, `LAST_INSERT_ID()' should not be reset to 0. Now
     `LAST_INSERT_ID()' is reset to 0 only if no rows were successfully
     inserted or touched, whether or not touched rows were changed.
     (Bug #27033) See also Bug #27210, Bug #27006.

     This regression was introduced by Bug #19978.

   * *Note `mysql_install_db': mysql-install-db. could terminate with an
     error after failing to determine that a system table already
     existed.  (Bug #27022)

   * `AFTER UPDATE' triggers were not activated by the update part of
     *Note `INSERT ... ON DUPLICATE KEY UPDATE': insert-on-duplicate.
     statements.  (Bug #27006) See also Bug #27033, Bug #27210.

     This regression was introduced by Bug #19978.

   * In a `MEMORY' table, using a `BTREE' index to scan for updatable
     rows could lead to an infinite loop.  (Bug #26996)

   * Invalid optimization of pushdown conditions for queries where an
     outer join was guaranteed to read only one row from the outer
     table led to results with too few rows.  (Bug #26963)

   * Windows binaries contained no debug symbol file. Now `.map' and
     `.pdb' files are included in 32-bit builds for *Note
     `mysqld-nt.exe': mysqld, *Note `mysqld-debug.exe': mysqld, and
     `mysqlmanager.exe'.  (Bug #26893)

   * For `MERGE' tables defined on underlying tables that contained a
     short *Note `VARCHAR': char.  column (shorter than four
     characters), using *Note `ALTER TABLE': alter-table. on at least
     one but not all of the underlying tables caused the table
     definitions to be considered different from that of the `MERGE'
     table, even if the *Note `ALTER TABLE': alter-table. did not
     change the definition.  (Bug #26881)

   * For `InnoDB' tables having a clustered index that began with a
     *Note `CHAR': char. or *Note `VARCHAR': char. column, deleting a
     record and then inserting another before the deleted record was
     purged could result in table corruption.  (Bug #26835)

   * Use of a subquery containing `GROUP BY' and `WITH ROLLUP' caused a
     server crash.  (Bug #26830)

   * Duplicates were not properly identified among (potentially) long
     strings used as arguments for `GROUP_CONCAT(DISTINCT)'.  (Bug
     #26815)

   * *Note `ALTER VIEW': alter-view. requires the `CREATE VIEW' and
     `DROP' privileges for the view.  However, if the view was created
     by another user, the server erroneously required the `SUPER'
     privilege.  (Bug #26813)

   * Added support for `--debugger=dbx' for `mysql-test-run.pl' and
     added support for `--debugger=devenv', `--debugger=DevEnv', and
     `--debugger=/PATH/TO/devenv'.  (Bug #26792)

   * A result set column formed by concatention of string literals was
     incomplete when the column was produced by a subquery in the
     `FROM' clause.  (Bug #26738)

   * SSL connections failed on Windows.  (Bug #26678)

   * When using the result of `SEC_TO_TIME()' for time value greater
     than 24 hours in an `ORDER BY' clause, either directly or through
     a column alias, the rows were sorted incorrectly as strings.  (Bug
     #26672)

   * Use of a subquery containing a *Note `UNION': union. with an
     invalid `ORDER BY' clause caused a server crash.  (Bug #26661)

   * The range optimizer could cause the server to run out of memory.
     (Bug #26625)

   * The range optimizer could consume a combinatorial amount of memory
     for certain classes of `WHERE' clauses.  (Bug #26624)

   * In some error messages, inconsistent format specifiers were used
     for the translations in different languages.  *Note `comp_err':
     comp-err. (the error message compiler) now checks for mismatches.
     (Bug #26571)

   * Views that used a scalar correlated subquery returned incorrect
     results.  (Bug #26560)

   * `UNHEX() IS NULL' comparisons failed when `UNHEX()' returned
     `NULL'.  (Bug #26537)

   * On 64-bit Windows, large timestamp values could be handled
     incorrectly.  (Bug #26536)

   * `mysqldump' could crash or exhibit incorrect behavior when some
     options were given very long values, such as
     `--fields-terminated-by="SOME VERY LONG STRING"'. The code has
     been cleaned up to remove a number of fixed-sized buffers and to
     be more careful about error conditions in memory allocation.  (Bug
     #26346)

   * If the server was started with `--skip-grant-tables', selecting
     from `INFORMATION_SCHEMA' tables caused a server crash.  (Bug
     #26285)

   * For some values of the position argument, the `INSERT()' function
     could insert a NUL byte into the result.  (Bug #26281)

   * For an *Note `INSERT': insert. statement that should fail due to a
     column with no default value not being assigned a value, the
     statement succeeded with no error if the column was assigned a
     value in an `ON DUPLICATE KEY UPDATE' clause, even if that clause
     was not used.  (Bug #26261)

   * *Note `INSERT DELAYED': insert-delayed. statements inserted
     incorrect values into *Note `BIT': numeric-types. columns.  (Bug
     #26238)

   * The temporary file-creation code was cleaned up on Windows to
     improve server stability.  (Bug #26233)

   * For `MyISAM' tables, `COUNT(*)' could return an incorrect value if
     the `WHERE' clause compared an indexed *Note `TEXT': blob. column
     to the empty string (`'''). This happened if the column contained
     empty strings and also strings starting with control characters
     such as tab or newline.  (Bug #26231)

   * For *Note `INSERT INTO ... SELECT': insert-select. where index
     searches used column prefixes, insert errors could occur when key
     value type conversion was done.  (Bug #26207)

   * For `DELETE FROM `tbl_name' ORDER BY COL_NAME' (with no `WHERE' or
     `LIMIT' clause), the server did not check whether COL_NAME was a
     valid column in the table.  (Bug #26186)

   * `REPAIR TABLE ... USE_FRM' with an `ARCHIVE' table deleted all
     records from the table.  (Bug #26138)

   * `BENCHMARK()' did not work correctly for expressions that produced
     a *Note `DECIMAL': numeric-types. result.  (Bug #26093)

   * *Note `LOAD DATA INFILE': load-data. sent an okay to the client
     before writing the binary log and committing the changes to the
     table had finished, thus violating ACID requirements.  (Bug #26050)

   * `X() IS NULL' and `Y() IS NULL' comparisons failed when `X()' and
     `Y()' returned `NULL'.  (Bug #26038)

   * *Note `mysqldump': mysqldump. crashed for `MERGE' tables if the
     `--complete-insert' (`-c') option was given.  (Bug #25993)

   * Indexes on *Note `TEXT': blob. columns were ignored when `ref'
     accesses were evaluated.  (Bug #25971)

   * If a thread previously serviced a connection that was killed,
     excessive memory and CPU use by the thread occurred if it later
     serviced a connection that had to wait for a table lock.  (Bug
     #25966)

   * Setting a column to `NOT NULL' with an `ON DELETE SET NULL' clause
     foreign key crashes the server.  (Bug #25927)

   * `VIEW' restrictions were applied to *Note `SELECT': select.
     statements after a *Note `CREATE VIEW': create-view. statement
     failed, as though the `CREATE' had succeeded.  (Bug #25897)

   * Several deficiencies in resolution of column names for *Note
     `INSERT ... SELECT': insert-select. statements were corrected.
     (Bug #25831)

   * Inserting `utf8' data into a *Note `TEXT': blob. column that used a
     single-byte character set could result in spurious warnings about
     truncated data.  (Bug #25815)

   * On Windows, debug builds of *Note `mysqld': mysqld. could fail
     with heap assertions.  (Bug #25765)

   * In certain situations, `MATCH ... AGAINST' returned false hits for
     `NULL' values produced by `LEFT JOIN' when no full-text index was
     available.  (Bug #25729)

   * In certain cases it could happen that deleting a row corrupted an
     `RTREE' index. This affected indexes on spatial columns.  (Bug
     #25673)

   * *Note `OPTIMIZE TABLE': optimize-table. might fail on Windows when
     it attempts to rename a temporary file to the original name if the
     original file had been opened, resulting in loss of the `.MYD'
     file.  (Bug #25521)

   * For *Note `SHOW ENGINE INNODB STATUS': show-engine, the `LATEST
     DEADLOCK INFORMATION' was not always cleared properly.  (Bug
     #25494)

   * *Note `mysql_stmt_fetch()': mysql-stmt-fetch. did an invalid
     memory deallocation when used with the embedded server.  (Bug
     #25492)

   * Expressions involving `SUM()', when used in an `ORDER BY' clause,
     could lead to out-of-order results.  (Bug #25376)

   * Use of a `GROUP BY' clause that referred to a stored function
     result together with `WITH ROLLUP' caused incorrect results.  (Bug
     #25373)

   * A stored procedure that made use of cursors failed when the
     procedure was invoked from a stored function.  (Bug #25345)

   * Difficult repair or optimization operations could cause an
     assertion failure, resulting in a server crash.  (Bug #25289)

   * On Windows, the server exhibited a file-handle leak after reaching
     the limit on the number of open file descriptors.  (Bug #25222)

   * The `REPEAT()' function did not permit a column name as the COUNT
     parameter.  (Bug #25197)

   * A reference to a nonexistent column in the `ORDER BY' clause of an
     `UPDATE ... ORDER BY' statement could cause a server crash.  (Bug
     #25126)

   * A view on a join is insertable for *Note `INSERT': insert.
     statements that store values into only one table of the join.
     However, inserts were being rejected if the inserted-into table
     was used in a self-join because MySQL incorrectly was considering
     the insert to modify multiple tables of the view.  (Bug #25122)

   * MySQL would not compile when configured using
     `--without-query-cache'.  (Bug #25075)

   * Duplicate entries were not assessed correctly in a `MEMORY' table
     with a `BTREE' primary key on a `utf8' *Note `ENUM': enum. column.
     (Bug #24985)

   * Selecting the result of `AVG()' within a *Note `UNION': union.
     could produce incorrect values.  (Bug #24791)

   * `MBROverlaps()' returned incorrect values in some cases.  (Bug
     #24563)

   * Increasing the width of a *Note `DECIMAL': numeric-types.  column
     could cause column values to be changed.  (Bug #24558)

   * IF(EXPR, UNSIGNED_EXPR, UNSIGNED_EXPR) was evaluated to a signed
     result, not unsigned. This has been corrected. The fix also
     affects constructs of the form `IS [NOT] {TRUE|FALSE}', which were
     transformed internally into `IF()' expressions that evaluated to a
     signed result.

     For existing views that were defined using `IS [NOT] {TRUE|FALSE}'
     constructs, there is a related implication. The definitions of
     such views were stored using the `IF()' expression, not the
     original construct. This is manifest in that *Note `SHOW CREATE
     VIEW': show-create-view. shows the transformed `IF()' expression,
     not the original one. Existing views will evaluate correctly after
     the fix, but if you want *Note `SHOW CREATE VIEW':
     show-create-view. to display the original construct, you must drop
     the view and re-create it using its original definition. New views
     will retain the construct in their definition.  (Bug #24532)

   * A problem in handling of aggregate functions in subqueries caused
     predicates containing aggregate functions to be ignored during
     query execution.  (Bug #24484)

   * The test for the `MYSQL_OPT_SSL_VERIFY_SERVER_CERT' option for
     *Note `mysql_options()': mysql-options. was performed incorrectly.
     Also changed as a result of this bug fix: The `arg' option for the
     *Note `mysql_options()': mysql-options. C API function was changed
     from `char *' to `void *'.  (Bug #24121)

   * A user-defined variable could be assigned an incorrect value if a
     temporary table was employed in obtaining the result of the query
     used to determine its value.  (Bug #24010)

   * Queries that used a temporary table for the outer query when
     evaluating a correlated subquery could return incorrect results.
     (Bug #23800)

   * On Windows, debug builds of *Note `mysqlbinlog': mysqlbinlog. could
     fail with a memory error.  (Bug #23736)

   * When using certain server SQL modes, the `mysql.proc' table was
     not created by *Note `mysql_install_db': mysql-install-db.  (Bug
     #23669)

   * The values displayed for the `Innodb_row_lock_time',
     `Innodb_row_lock_time_avg', and `Innodb_row_lock_time_max' status
     variables were incorrect.  (Bug #23666)

   * *Note `DOUBLE': numeric-types. values such as
     `20070202191048.000000' were being treated as illegal arguments by
     `WEEK()'.  (Bug #23616)

   * The server could crash if two or more threads initiated query
     cache resize operation at moments very close in time.  (Bug #23527)

   * *Note `SHOW CREATE VIEW': show-create-view. qualified references
     to stored functions in the view definition with the function's
     database name, even when the database was the default database.
     This affected *Note `mysqldump': mysqldump. (which uses *Note
     `SHOW CREATE VIEW': show-create-view. to dump views) because the
     resulting dump file could not be used to reload the database into
     a different database. *Note `SHOW CREATE VIEW': show-create-view.
     now suppresses the database name for references to stored
     functions in the default database.  (Bug #23491)

   * An `INTO OUTFILE' clause is permitted only for the final *Note
     `SELECT': select. of a *Note `UNION': union, but this restriction
     was not being enforced correctly.  (Bug #23345)

   * `NOW()' returned the wrong value in statements executed at server
     startup with the `--init-file' option.  (Bug #23240)

   * With the `NO_AUTO_VALUE_ON_ZERO' SQL mode enabled,
     `LAST_INSERT_ID()' could return 0 after *Note `INSERT ... ON
     DUPLICATE KEY UPDATE': insert-on-duplicate. Additionally, the next
     rows inserted (by the same *Note `INSERT': insert, or the
     following *Note `INSERT': insert. with or without `ON DUPLICATE
     KEY UPDATE'), would insert 0 for the auto-generated value if the
     value for the `AUTO_INCREMENT' column was `NULL' or missing.  (Bug
     #23233)

   * `SOUNDEX()' returned an invalid string for international
     characters in multi-byte character sets.  (Bug #22638)

   * When nesting stored procedures within a trigger on a table, a
     false dependency error was thrown when one of the nested
     procedures contained a *Note `DROP TABLE': drop-table.  statement.
     (Bug #22580)

   * Instance Manager did not remove the angel PID file on a clean
     shutdown.  (Bug #22511)

   * *Note `EXPLAIN EXTENDED': explain. did not show `WHERE' conditions
     that were optimized away.  (Bug #22331)

   * `COUNT(DECIMAL_EXPR)' sometimes generated a spurious truncation
     warning.  (Bug #21976)

   * `IN ((SUBQUERY))', `IN (((SUBQUERY)))', and so forth, are
     equivalent to `IN (SUBQUERY)', which is always interpreted as a
     table subquery (so that it is permitted to return more than one
     row). MySQL was treating the `over-parenthesized' subquery as a
     single-row subquery and rejecting it if it returned more than one
     row. This bug primarily affected automatically generated code
     (such as queries generated by Hibernate), because humans rarely
     write the over-parenthesized forms.  (Bug #21904)

   * An `INSERT' trigger invoking a stored routine that inserted into a
     table other than the one on which the trigger was defined would
     fail with a `Table '...'  doesn't exist' referring to the second
     table when attempting to delete records from the first table.
     (Bug #21825)

   * `InnoDB': The first read statement, if served from the query
     cache, was not consistent with the `READ COMMITTED' isolation
     level.  (Bug #21409)

   * `CURDATE()' is less than `NOW()', either when comparing
     `CURDATE()' directly (`CURDATE() < NOW()' is true) or when casting
     `CURDATE()' to *Note `DATE': datetime. (`CAST(CURDATE() AS DATE) <
     NOW()' is true). However, storing `CURDATE()' in a *Note `DATE':
     datetime. column and comparing `COL_NAME < NOW()' incorrectly
     yielded false. This is fixed by comparing a *Note `DATE':
     datetime. column as *Note `DATETIME': datetime. for comparisons to
     a *Note `DATETIME': datetime. constant.  (Bug #21103)

   * When a stored routine attempted to execute a statement accessing a
     nonexistent table, the error was not caught by the routine's
     exception handler.  (Bug #20713, Bug #8407)

   * For a stored procedure containing a *Note `SELECT': select.
     statement that used a complicated join with an `ON' expression, the
     expression could be ignored during re-execution of the procedure,
     yielding an incorrect result.  (Bug #20492)

   * The conditions checked by the optimizer to permit use of indexes
     in `IN' predicate calculations were unnecessarily tight and were
     relaxed.  (Bug #20420)

   * When a `TIME_FORMAT()' expression was used as a column in a `GROUP
     BY' clause, the expression result was truncated.  (Bug #20293)

   * The creation of MySQL system tables was not checked for by
     `mysql-test-run.pl'.  (Bug #20166)

   * For index reads, the `BLACKHOLE' engine did not return end-of-file
     (which it must because `BLACKHOLE' tables contain no rows), causing
     some queries to crash.  (Bug #19717)

   * In some cases, the optimizer preferred a range or full index scan
     access method over lookup access methods when the latter were much
     cheaper.  (Bug #19372)

   * For `EXPR IN(VALUE_LIST)', the result could be incorrect if
     `BIGINT UNSIGNED' values were used for EXPR or in the value list.
     (Bug #19342)

   * When attempting to call a stored procedure creating a table from a
     trigger on a table `tbl' in a database `db', the trigger failed
     with `ERROR 1146 (42S02): Table 'db.tbl' doesn't exist'. However,
     the actual reason that such a trigger fails is due to the fact
     that *Note `CREATE TABLE': create-table. causes an implicit *Note
     `COMMIT': commit, and so a trigger cannot invoke a stored routine
     containing this statement. A trigger which does so now fails with
     `ERROR 1422 (HY000): Explicit or implicit commit is not permitted
     in stored function or trigger', which makes clear the reason for
     the trigger's failure.  (Bug #18914)

   * The update columns for `INSERT ... SELECT ... ON DUPLICATE KEY
     UPDATE' could be assigned incorrect values if a temporary table
     was used to evaluate the *Note `SELECT': select.  (Bug #16630)

   * Conversion of *Note `DATETIME': datetime. values in numeric
     contexts sometimes did not produce a double
     (`YYYYMMDDHHMMSS.uuuuuu') value.  (Bug #16546)

   * For `SUBSTRING()' evaluation using a temporary table, when
     `SUBSTRING()' was used on a LONGTEXT column, the `max_length'
     metadata value of the result was incorrectly calculated and set to
     0.  Consequently, an empty string was returned instead of the
     correct result.  (Bug #15757)

   * Local variables in stored routines or triggers, when declared as
     the *Note `BIT': numeric-types. type, were interpreted as strings.
     (Bug #12976)

   * `CONNECTION' is no longer treated as a reserved word.  (Bug #12204)


File: manual.info,  Node: news-5-0-40,  Next: news-5-0-38,  Prev: news-5-0-41,  Up: news-5-0-x

D.1.57 Changes in MySQL Enterprise 5.0.40 [MRU] (17 April 2007)
---------------------------------------------------------------

This is a _Monthly Rapid Update_ release of the MySQL Enterprise Server
5.0.

This section documents all changes and bug fixes that have been applied
since the last MySQL Enterprise Server release (5.0.38).

*Functionality Added or Changed*

   * *MySQL Cluster*: The behavior of the *Note `ndb_restore':
     mysql-cluster-programs-ndb-restore. utility has been changed as
     follows:

        * It is now possible to restore selected databases or tables
          using *Note `ndb_restore': mysql-cluster-programs-ndb-restore.

        * Several options have been added for use with *Note
          `ndb_restore': mysql-cluster-programs-ndb-restore.
          `--print_data' to facilitate the creation of structured data
          dump files. These options can be used to make dumps made using
          *Note `ndb_restore': mysql-cluster-programs-ndb-restore. more
          like those produced by *Note `mysqldump': mysqldump.

     For details of these changes, see *Note
     mysql-cluster-programs-ndb-restore::.  (Bug #26899, Bug #26900)

   * If a set function S with an outer reference ` S(OUTER_REF)' cannot
     be aggregated in the outer query against which the outer reference
     has been resolved, MySQL interprets ` S(OUTER_REF)' the same way
     that it would interpret ` S(CONST)'.  However, standard SQL
     requires throwing an error in this situation. An error now is
     thrown for such queries if the `ANSI' SQL mode is enabled.  (Bug
     #27348)

   * Added the `--service-startup-timeout' option for *Note
     `mysql.server': mysql-server. to specify how long to wait for the
     server to start. If the server does not start within the timeout
     period, *Note `mysql.server': mysql-server. exits with an error.
     (Bug #26952)

   * Prefix lengths for columns in `SPATIAL' indexes are no longer
     displayed in *Note `SHOW CREATE TABLE': show-create-table. output.
     *Note `mysqldump': mysqldump. uses that statement, so if a table
     with `SPATIAL' indexes containing prefixed columns is dumped and
     reloaded, the index is created with no prefixes. (The full column
     width of each column is indexed.)  (Bug #26794)

   * The output of *Note `mysql': mysql.  `--xml' and *Note
     `mysqldump': mysqldump.  `--xml' now includes a valid XML
     namespace.  (Bug #25946)

   * If you use SSL for a client connection, you can tell the client
     not to authenticate the server certificate by specifying neither
     `--ssl-ca' nor `--ssl-capath'. The server still verifies the
     client according to any applicable requirements established using
     *Note `GRANT': grant.  statements for the client, and it still
     uses any `--ssl-ca'/`--ssl-capath' values that were passed to
     server at startup time.  (Bug #25309)

   * The syntax for index hints has been extended to enable explicit
     specification that the hint applies only to join processing. See
     *Note index-hints::.

     This is a new fix for this issue, and replaces the fix made in
     MySQL 5.0.25 and reverted in 5.0.26.  (Bug #21174)

   * The `mysql_create_system_tables' script was removed because *Note
     `mysql_install_db': mysql-install-db. no longer uses it in MySQL
     5.0.

*Bugs Fixed*

   * *Important Note*: The parser accepted invalid code in SQL
     condition handlers, leading to server crashes or unexpected
     execution behavior in stored programs. Specifically, the parser
     permitted a condition handler to refer to labels for blocks that
     enclose the handler declaration. This was incorrect because block
     label scope does not include the code for handlers declared within
     the labeled block.

     The parser now rejects this invalid construct, but if you perform
     a binary upgrade (without dumping and reloading your databases),
     existing handlers that contain the construct are still invalid and
     should be rewritten _even if they appear to function as you
     expect._

     To find affected handlers, use *Note `mysqldump': mysqldump. to
     dump all stored procedures and functions, triggers, and events.
     Then attempt to reload them into an upgraded server. Handlers that
     contain illegal label references will be rejected.

     For more information about condition handlers and writing them to
     avoid invalid jumps, see *Note declare-handler::.  (Bug #26503)

   * *MySQL Cluster*: *Note `NDB': mysql-cluster. tables having
     `MEDIUMINT AUTO_INCREMENT' columns were not restored correctly by
     *Note `ndb_restore': mysql-cluster-programs-ndb-restore, causing
     spurious duplicate key errors. This issue did not affect *Note
     `TINYINT': numeric-types, *Note `INT': numeric-types, or *Note
     `BIGINT': numeric-types. columns with `AUTO_INCREMENT'.  (Bug
     #27775)

   * *MySQL Cluster*: *Note `NDB': mysql-cluster. tables with indexes
     whose names contained space characters were not restored correctly
     by *Note `ndb_restore': mysql-cluster-programs-ndb-restore. (the
     index names were truncated).  (Bug #27758)

   * *MySQL Cluster*: Under certain rare circumstances performing a
     *Note `DROP TABLE': drop-table. or *Note `TRUNCATE TABLE':
     truncate-table. on an *Note `NDB': mysql-cluster. table could
     cause a node failure or forced cluster shutdown.  (Bug #27581)

   * *MySQL Cluster*: Memory usage of a *Note `mysqld': mysqld. process
     grew even while idle.  (Bug #27560)

   * *MySQL Cluster*: It was not possible to set `LockPagesInMainMemory'
     equal to `0'.  (Bug #27291)

   * *MySQL Cluster*: A race condition could sometimes occur if the
     node acting as master failed while node IDs were still being
     allocated during startup.  (Bug #27286)

   * *MySQL Cluster*: When a data node was taking over as the master
     node, a race condition could sometimes occur as the node was
     assuming responsibility for handling of global checkpoints.  (Bug
     #27283)

   * *MySQL Cluster*: Error messages displayed when running in single
     user mode were inconsistent.  (Bug #27021)

   * *MySQL Cluster*: The failure of a data node while restarting could
     cause other data nodes to hang or crash.  (Bug #27003)

   * *MySQL Cluster*: On Solaris, the value of an *Note `NDB':
     mysql-cluster.  table column declared as `BIT(33)' was always
     displayed as `0'.  (Bug #26986)

   * *MySQL Cluster*: *Note `mysqld': mysqld. processes would sometimes
     crash under high load.  (Bug #26825)

   * *MySQL Cluster*: The output from *Note `ndb_restore
     `--print_data'': mysql-cluster-programs-ndb-restore. was incorrect
     for a backup made of a database containing tables with *Note
     `TINYINT': numeric-types. or *Note `SMALLINT': numeric-types.
     columns.  (Bug #26740)

   * *MySQL Cluster*: In some cases, `AFTER UPDATE' and `AFTER DELETE'
     triggers on *Note `NDB': mysql-cluster. tables that referenced
     subject table did not see the results of operation which caused
     invocation of the trigger, but rather saw the row as it was prior
     to the update or delete operation.

     This was most noticeable when an update operation used a subquery
     to obtain the rows to be updated. An example would be `UPDATE tbl1
     SET col2 = val1 WHERE tbl1.col1 IN (SELECT col3 FROM tbl2 WHERE c4
     = val2)' where there was an `AFTER UPDATE' trigger on table
     `tbl1'. In such cases, the trigger would fail to execute.

     The problem occurred because the actual update or delete
     operations were deferred to be able to perform them later as one
     batch. The fix for this bug solves the problem by disabling this
     optimization for a given update or delete if the table has an
     `AFTER' trigger defined for this operation.  (Bug #26242)

   * *MySQL Cluster*: Condition pushdown did not work with prepared
     statements.  (Bug #26225)

   * *MySQL Cluster*: Joins on multiple tables containing *Note `BLOB':
     blob. columns could cause data nodes run out of memory, and to
     crash with the error `NdbObjectIdMap::expand unable to expand'.
     (Bug #26176)

   * *MySQL Cluster*: After entering single user mode it was not
     possible to alter non-*Note `NDB': mysql-cluster. tables on any
     SQL nodes other than the one having sole access to the cluster.
     (Bug #25275)

   * *MySQL Cluster*: When a cluster data node suffered a `hard' failure
     (such as a power failure or loss of a network connection) TCP
     sockets to the missing node were maintained indefinitely. Now
     socket-based transporters check for a response and terminate the
     socket if there is no activity on the socket after 2 hours.  (Bug
     #24793)

   * *MySQL Cluster*: The management client command ` NODE_ID STATUS'
     displayed the message `Node NODE_ID: not connected' when NODE_ID
     was not the node ID of a data node.

     *Note*:

     The `ALL STATUS' command in the cluster management client still
     displays status information for data nodes only. This is by
     design. See *Note mysql-cluster-mgm-client-commands::, for more
     information.

     (Bug #21715)

   * *MySQL Cluster*: Some values of `MaxNoOfTables' caused the error
     `Job buffer congestion' to occur.  (Bug #19378)

   * *MySQL Cluster*: When trying to create tables on an SQL node not
     connected to the cluster, a misleading error message `Table
     'TBL_NAME' already exists' was generated. The error now generated
     is `Could not connect to storage engine'.  (Bug #11217, Bug #18676)

   * *Replication*: Out-of-memory errors were not reported. Now they
     are written to the error log.  (Bug #26844)

   * *Replication*: Improved out-of-memory detection when sending logs
     from a master server to slaves, and log a message when allocation
     fails.  (Bug #26837)

   * *Replication*: When `RAND()' was called multiple times inside a
     stored procedure, the server did not write the correct random seed
     values to the binary log, resulting in incorrect replication.
     (Bug #25543)

   * *Replication*: *Note `GRANT': grant. statements were not
     replicated if the server was started with the
     `--replicate-ignore-table' or `--replicate-wild-ignore-table'
     option.  (Bug #25482)

   * *Replication*: Replication between master and slave would
     infinitely retry binary log transmission where the
     `max_allowed_packet' on the master was larger than that on the
     slave if the size of the transfer was between these two values.
     (Bug #23775)

   * *Cluster Replication*: Some queries that updated multiple tables
     were not backed up correctly.  (Bug #27748)

   * *Cluster API*: Using `NdbBlob::writeData()' to write data in the
     middle of an existing blob value (that is, updating the value)
     could overwrite some data past the end of the data to be changed.
     (Bug #27018)

   * *Cluster API*: After defining a delete operation (using
     `NdbOperation::deleteTuple()') on a nonexistent primary key of a
     table having a *Note `BLOB': blob. or *Note `TEXT': blob. column,
     invoking `NdbTransaction::execute()' caused the calling
     application to enter an endless loop rather than raising an error.

     This issue also affected *Note `ndb_restore':
     mysql-cluster-programs-ndb-restore.; when restoring tables
     containing *Note `BLOB': blob.  or *Note `TEXT': blob. columns,
     this could cause it to consume all available memory and then crash.
     (Bug #24028) See also Bug #27308, Bug #30177.

   * Some equi-joins containing a `WHERE' clause that included a `NOT
     IN' subquery caused a server crash.  (Bug #27870)

   * *Note `SELECT DISTINCT': select. could return incorrect results if
     the select list contained duplicated columns.  (Bug #27659)

   * With `NO_AUTO_VALUE_ON_ZERO' SQL mode enabled, *Note `LOAD DATA':
     load-data.  operations could assign incorrect `AUTO_INCREMENT'
     values.  (Bug #27586)

   * Incorrect results could be returned for some queries that
     contained a select list expression with `IN' or `BETWEEN' together
     with an `ORDER BY' or `GROUP BY' on the same expression using `NOT
     IN' or `NOT BETWEEN'.  (Bug #27532)

   * Evaluation of an `IN()' predicate containing a decimal-valued
     argument caused a server crash.  (Bug #27513, Bug #27362,
     CVE-2007-2583)

   * In out-of-memory conditions, the server might crash or otherwise
     not report an error to the Windows event log.  (Bug #27490)

   * Passing nested row expressions with different structures to an
     `IN' predicate caused a server crash.  (Bug #27484)

   * The `decimal.h' header file was incorrectly omitted from binary
     distributions.  (Bug #27456)

   * With `innodb_file_per_table' enabled, attempting to rename an
     `InnoDB' table to a nonexistent database caused the server to exit.
     (Bug #27381)

   * A subquery could get incorrect values for references to outer
     query columns when it contained aggregate functions that were
     aggregated in outer context.  (Bug #27321)

   * The server did not shut down cleanly.  (Bug #27310)

   * In a view, a column that was defined using a `GEOMETRY' function
     was treated as having the *Note `LONGBLOB': blob. data type rather
     than the `GEOMETRY' type.  (Bug #27300)

   * Queries containing subqueries with `COUNT(*)' aggregated in an
     outer context returned incorrect results. This happened only if the
     subquery did not contain any references to outer columns.  (Bug
     #27257)

   * Use of an aggregate function from an outer context as an argument
     to `GROUP_CONCAT()' caused a server crash.  (Bug #27229)

   * String truncation upon insertion into an integer or year column
     did not generate a warning (or an error in strict mode).  (Bug
     #27176, Bug #26359)

   * Storing `NULL' values in spatial fields caused excessive memory
     allocation and crashes on some systems.  (Bug #27164)

   * Row equalities in `WHERE' clauses could cause memory corruption.
     (Bug #27154)

   * `GROUP BY' on a `ucs2' column caused a server crash when there was
     at least one empty string in the column.  (Bug #27079)

   * Duplicate members in *Note `SET': set. or *Note `ENUM': enum.
     definitions were not detected. Now they result in a warning; if
     strict SQL mode is enabled, an error occurs instead.  (Bug #27069)

   * For *Note `INSERT ... ON DUPLICATE KEY UPDATE':
     insert-on-duplicate. statements on tables containing
     `AUTO_INCREMENT' columns, `LAST_INSERT_ID()' was reset to 0 if no
     rows were successfully inserted or changed. `Not changed' includes
     the case where a row was updated to its current values, but in
     that case, `LAST_INSERT_ID()' should not be reset to 0. Now
     `LAST_INSERT_ID()' is reset to 0 only if no rows were successfully
     inserted or touched, whether or not touched rows were changed.
     (Bug #27033) See also Bug #27210, Bug #27006.

     This regression was introduced by Bug #19978.

   * *Note `mysql_install_db': mysql-install-db. could terminate with an
     error after failing to determine that a system table already
     existed.  (Bug #27022)

   * In a `MEMORY' table, using a `BTREE' index to scan for updatable
     rows could lead to an infinite loop.  (Bug #26996)

   * Invalid optimization of pushdown conditions for queries where an
     outer join was guaranteed to read only one row from the outer
     table led to results with too few rows.  (Bug #26963)

   * Windows binaries contained no debug symbol file. Now `.map' and
     `.pdb' files are included in 32-bit builds for *Note
     `mysqld-nt.exe': mysqld, *Note `mysqld-debug.exe': mysqld, and
     `mysqlmanager.exe'.  (Bug #26893)

   * For `InnoDB' tables having a clustered index that began with a
     *Note `CHAR': char. or *Note `VARCHAR': char. column, deleting a
     record and then inserting another before the deleted record was
     purged could result in table corruption.  (Bug #26835)

   * Duplicates were not properly identified among (potentially) long
     strings used as arguments for `GROUP_CONCAT(DISTINCT)'.  (Bug
     #26815)

   * *Note `ALTER VIEW': alter-view. requires the `CREATE VIEW' and
     `DROP' privileges for the view.  However, if the view was created
     by another user, the server erroneously required the `SUPER'
     privilege.  (Bug #26813)

   * A result set column formed by concatention of string literals was
     incomplete when the column was produced by a subquery in the
     `FROM' clause.  (Bug #26738)

   * When using the result of `SEC_TO_TIME()' for time value greater
     than 24 hours in an `ORDER BY' clause, either directly or through
     a column alias, the rows were sorted incorrectly as strings.  (Bug
     #26672)

   * The range optimizer could cause the server to run out of memory.
     (Bug #26625)

   * The range optimizer could consume a combinatorial amount of memory
     for certain classes of `WHERE' clauses.  (Bug #26624)

   * `mysqldump' could crash or exhibit incorrect behavior when some
     options were given very long values, such as
     `--fields-terminated-by="SOME VERY LONG STRING"'. The code has
     been cleaned up to remove a number of fixed-sized buffers and to
     be more careful about error conditions in memory allocation.  (Bug
     #26346)

   * If the server was started with `--skip-grant-tables', selecting
     from `INFORMATION_SCHEMA' tables caused a server crash.  (Bug
     #26285)

   * For an *Note `INSERT': insert. statement that should fail due to a
     column with no default value not being assigned a value, the
     statement succeeded with no error if the column was assigned a
     value in an `ON DUPLICATE KEY UPDATE' clause, even if that clause
     was not used.  (Bug #26261)

   * The temporary file-creation code was cleaned up on Windows to
     improve server stability.  (Bug #26233)

   * For `MyISAM' tables, `COUNT(*)' could return an incorrect value if
     the `WHERE' clause compared an indexed *Note `TEXT': blob. column
     to the empty string (`'''). This happened if the column contained
     empty strings and also strings starting with control characters
     such as tab or newline.  (Bug #26231)

   * For *Note `INSERT INTO ... SELECT': insert-select. where index
     searches used column prefixes, insert errors could occur when key
     value type conversion was done.  (Bug #26207)

   * For `DELETE FROM `tbl_name' ORDER BY COL_NAME' (with no `WHERE' or
     `LIMIT' clause), the server did not check whether COL_NAME was a
     valid column in the table.  (Bug #26186)

   * `REPAIR TABLE ... USE_FRM' with an `ARCHIVE' table deleted all
     records from the table.  (Bug #26138)

   * *Note `mysqldump': mysqldump. crashed for `MERGE' tables if the
     `--complete-insert' (`-c') option was given.  (Bug #25993)

   * Setting a column to `NOT NULL' with an `ON DELETE SET NULL' clause
     foreign key crashes the server.  (Bug #25927)

   * On Windows, debug builds of *Note `mysqld': mysqld. could fail
     with heap assertions.  (Bug #25765)

   * In certain situations, `MATCH ... AGAINST' returned false hits for
     `NULL' values produced by `LEFT JOIN' when no full-text index was
     available.  (Bug #25729)

   * *Note `OPTIMIZE TABLE': optimize-table. might fail on Windows when
     it attempts to rename a temporary file to the original name if the
     original file had been opened, resulting in loss of the `.MYD'
     file.  (Bug #25521)

   * For *Note `SHOW ENGINE INNODB STATUS': show-engine, the `LATEST
     DEADLOCK INFORMATION' was not always cleared properly.  (Bug
     #25494)

   * *Note `mysql_stmt_fetch()': mysql-stmt-fetch. did an invalid
     memory deallocation when used with the embedded server.  (Bug
     #25492)

   * Difficult repair or optimization operations could cause an
     assertion failure, resulting in a server crash.  (Bug #25289)

   * Duplicate entries were not assessed correctly in a `MEMORY' table
     with a `BTREE' primary key on a `utf8' *Note `ENUM': enum. column.
     (Bug #24985)

   * Selecting the result of `AVG()' within a *Note `UNION': union.
     could produce incorrect values.  (Bug #24791)

   * `MBROverlaps()' returned incorrect values in some cases.  (Bug
     #24563)

   * Increasing the width of a *Note `DECIMAL': numeric-types.  column
     could cause column values to be changed.  (Bug #24558)

   * A problem in handling of aggregate functions in subqueries caused
     predicates containing aggregate functions to be ignored during
     query execution.  (Bug #24484)

   * The test for the `MYSQL_OPT_SSL_VERIFY_SERVER_CERT' option for
     *Note `mysql_options()': mysql-options. was performed incorrectly.
     Also changed as a result of this bug fix: The `arg' option for the
     *Note `mysql_options()': mysql-options. C API function was changed
     from `char *' to `void *'.  (Bug #24121)

   * On Windows, debug builds of *Note `mysqlbinlog': mysqlbinlog. could
     fail with a memory error.  (Bug #23736)

   * The values displayed for the `Innodb_row_lock_time',
     `Innodb_row_lock_time_avg', and `Innodb_row_lock_time_max' status
     variables were incorrect.  (Bug #23666)

   * *Note `SHOW CREATE VIEW': show-create-view. qualified references
     to stored functions in the view definition with the function's
     database name, even when the database was the default database.
     This affected *Note `mysqldump': mysqldump. (which uses *Note
     `SHOW CREATE VIEW': show-create-view. to dump views) because the
     resulting dump file could not be used to reload the database into
     a different database. *Note `SHOW CREATE VIEW': show-create-view.
     now suppresses the database name for references to stored
     functions in the default database.  (Bug #23491)

   * An `INTO OUTFILE' clause is permitted only for the final *Note
     `SELECT': select. of a *Note `UNION': union, but this restriction
     was not being enforced correctly.  (Bug #23345)

   * With the `NO_AUTO_VALUE_ON_ZERO' SQL mode enabled,
     `LAST_INSERT_ID()' could return 0 after *Note `INSERT ... ON
     DUPLICATE KEY UPDATE': insert-on-duplicate. Additionally, the next
     rows inserted (by the same *Note `INSERT': insert, or the
     following *Note `INSERT': insert. with or without `ON DUPLICATE
     KEY UPDATE'), would insert 0 for the auto-generated value if the
     value for the `AUTO_INCREMENT' column was `NULL' or missing.  (Bug
     #23233)

   * `SOUNDEX()' returned an invalid string for international
     characters in multi-byte character sets.  (Bug #22638)

   * `COUNT(DECIMAL_EXPR)' sometimes generated a spurious truncation
     warning.  (Bug #21976)

   * `InnoDB': The first read statement, if served from the query
     cache, was not consistent with the `READ COMMITTED' isolation
     level.  (Bug #21409)

   * For a stored procedure containing a *Note `SELECT': select.
     statement that used a complicated join with an `ON' expression, the
     expression could be ignored during re-execution of the procedure,
     yielding an incorrect result.  (Bug #20492)

   * In some cases, the optimizer preferred a range or full index scan
     access method over lookup access methods when the latter were much
     cheaper.  (Bug #19372)

   * Conversion of *Note `DATETIME': datetime. values in numeric
     contexts sometimes did not produce a double
     (`YYYYMMDDHHMMSS.uuuuuu') value.  (Bug #16546)


File: manual.info,  Node: news-5-0-38,  Next: news-5-0-37,  Prev: news-5-0-40,  Up: news-5-0-x

D.1.58 Changes in MySQL Enterprise 5.0.38 [MRU] (20 March 2007)
---------------------------------------------------------------

This is a _Monthly Rapid Update_ release of the MySQL Enterprise Server
5.0.

This section documents all changes and bug fixes that have been applied
since the last MySQL Enterprise Server release (5.0.36).

*Functionality Added or Changed*

   * The server now includes a timestamp in error messages that are
     logged as a result of unhandled signals (such as `mysqld got
     signal 11' messages).  (Bug #24878)

   * Added the `--secure-file-priv' option for *Note `mysqld': mysqld,
     which limits the effect of the `LOAD_FILE()' function and the
     *Note `LOAD DATA': load-data. and *Note `SELECT ... INTO OUTFILE':
     select. statements to work only with files in a given directory.
     (Bug #18628)

   * Added the read-only `hostname' system variable, which the server
     sets at startup to the server host name.

   * To satisfy different user requirements, we provide several
     servers. *Note `mysqld': mysqld. is an optimized server that is a
     smaller, faster binary. Each package now also includes *Note
     `mysqld-debug': mysqld, which is compiled with debugging support
     but is otherwise configured identically to the nondebug server.

*Bugs Fixed*

   * *Incompatible Change*: *Note `INSERT DELAYED': insert-delayed.
     statements are not supported for `MERGE' tables, but the `MERGE'
     storage engine was not rejecting such statements, resulting in
     table corruption. Applications previously using *Note `INSERT
     DELAYED': insert-delayed.  into `MERGE' table will break when
     upgrading to versions with this fix. To avoid the problem, remove
     `DELAYED' from such statements.  (Bug #26464)

   * *MySQL Cluster*: An inadvertent use of unaligned data caused *Note
     `ndb_restore': mysql-cluster-programs-ndb-restore. to fail on some
     64-bit platforms, including Sparc and Itanium-2.  (Bug #26739)

   * *MySQL Cluster*: An infinite loop in an internal logging function
     could cause trace logs to fill up with `Unknown Signal type' error
     messages and thus grow to unreasonable sizes.  (Bug #26720)

   * *MySQL Cluster*: An invalid pointer was returned following a
     `FSCLOSECONF' signal when accessing the REDO logs during a node
     restart or system restart.  (Bug #26515)

   * *MySQL Cluster*: The failure of a data node when restarting it with
     `--initial' could lead to failures of subsequent data node
     restarts.  (Bug #26481)

   * *MySQL Cluster*: Takeover for local checkpointing due to multiple
     failures of master nodes was sometimes incorrectly handled.  (Bug
     #26457)

   * *MySQL Cluster*: The `LockPagesInMainMemory' parameter was not
     read until after distributed communication had already started
     between cluster nodes. When the value of this parameter was `1',
     this could sometimes result in data node failure due to missed
     heartbeats.  (Bug #26454)

   * *MySQL Cluster*: Under some circumstances, following the restart
     of a management node, all data nodes would connect to it normally,
     but some of them subsequently failed to log any events to the
     management node.  (Bug #26293)

   * *MySQL Cluster*: The message `Error 0 in readAutoIncrementValue():
     no Error' was written to the error log whenever *Note `SHOW TABLE
     STATUS': show-table-status. was performed on a Cluster table that
     did not have an `AUTO_INCREMENT' column.  (Bug #21033)

   * *Replication*: A multiple-row delayed insert with an
     auto-increment column could cause duplicate entries to be created
     on the slave in a replication environment.  (Bug #26116, Bug
     #25507)

   * *Replication*: Duplicating the usage of a user variable in a
     stored procedure or trigger would not be replicated correctly to
     the slave.  (Bug #25167)

   * *Replication*: *Note `DROP TRIGGER': drop-trigger. statements
     would not be filtered on the slave when using the
     `replication-wild-do-table' option.  (Bug #24478)

   * *Replication*: For *Note `INSERT ... ON DUPLICATE KEY UPDATE':
     insert-on-duplicate. statements where some `AUTO_INCREMENT' values
     were generated automatically for inserts and some rows were
     updated, one auto-generated value was lost per updated row,
     leading to faster exhaustion of the range of the `AUTO_INCREMENT'
     column.

     Because the original problem can affect replication (different
     values on master and slave), it is recommended that the master and
     its slaves be upgraded to the current version.  (Bug #24432)

   * *Replication*: Loading data using *Note `LOAD DATA INFILE':
     load-data. may not replicate correctly (due to character set
     incompatibilities) if the `character_set_database' variable is set
     before the data is loaded.  (Bug #15126)

   * *Replication*: User defined variables used within stored
     procedures and triggers are not replicated correctly when
     operating in statement-based replication mode.  (Bug #14914, Bug
     #20141)

   * *Note `SELECT ... INTO OUTFILE': select. with a long `FIELDS
     ENCLOSED BY' value could crash the server.  (Bug #27231)

   * An *Note `INSERT ... ON DUPLICATE KEY UPDATE':
     insert-on-duplicate. statement might modify values in a table but
     not flush affected data from the query cache, causing subsequent
     selects to return stale results. This made the combination of
     query cache plus `ON DUPLICATE KEY UPDATE' very unreliable.  (Bug
     #27210) See also Bug #27006, Bug #27033.

     This regression was introduced by Bug #19978.

   * For `MERGE' tables defined on underlying tables that contained a
     short *Note `VARCHAR': char.  column (shorter than four
     characters), using *Note `ALTER TABLE': alter-table. on at least
     one but not all of the underlying tables caused the table
     definitions to be considered different from that of the `MERGE'
     table, even if the *Note `ALTER TABLE': alter-table. did not
     change the definition.  (Bug #26881)

   * Use of a subquery containing `GROUP BY' and `WITH ROLLUP' caused a
     server crash.  (Bug #26830)

   * Added support for `--debugger=dbx' for `mysql-test-run.pl' and
     added support for `--debugger=devenv', `--debugger=DevEnv', and
     `--debugger=/PATH/TO/devenv'.  (Bug #26792)

   * SSL connections failed on Windows.  (Bug #26678)

   * Use of a subquery containing a *Note `UNION': union. with an
     invalid `ORDER BY' clause caused a server crash.  (Bug #26661)

   * In some error messages, inconsistent format specifiers were used
     for the translations in different languages.  *Note `comp_err':
     comp-err. (the error message compiler) now checks for mismatches.
     (Bug #26571)

   * Views that used a scalar correlated subquery returned incorrect
     results.  (Bug #26560)

   * `UNHEX() IS NULL' comparisons failed when `UNHEX()' returned
     `NULL'.  (Bug #26537)

   * On 64-bit Windows, large timestamp values could be handled
     incorrectly.  (Bug #26536)

   * For some values of the position argument, the `INSERT()' function
     could insert a NUL byte into the result.  (Bug #26281)

   * *Note `INSERT DELAYED': insert-delayed. statements inserted
     incorrect values into *Note `BIT': numeric-types. columns.  (Bug
     #26238)

   * `BENCHMARK()' did not work correctly for expressions that produced
     a *Note `DECIMAL': numeric-types. result.  (Bug #26093)

   * *Note `LOAD DATA INFILE': load-data. sent an okay to the client
     before writing the binary log and committing the changes to the
     table had finished, thus violating ACID requirements.  (Bug #26050)

   * `X() IS NULL' and `Y() IS NULL' comparisons failed when `X()' and
     `Y()' returned `NULL'.  (Bug #26038)

   * Indexes on *Note `TEXT': blob. columns were ignored when `ref'
     accesses were evaluated.  (Bug #25971)

   * If a thread previously serviced a connection that was killed,
     excessive memory and CPU use by the thread occurred if it later
     serviced a connection that had to wait for a table lock.  (Bug
     #25966)

   * `VIEW' restrictions were applied to *Note `SELECT': select.
     statements after a *Note `CREATE VIEW': create-view. statement
     failed, as though the `CREATE' had succeeded.  (Bug #25897)

   * Several deficiencies in resolution of column names for *Note
     `INSERT ... SELECT': insert-select. statements were corrected.
     (Bug #25831)

   * Inserting `utf8' data into a *Note `TEXT': blob. column that used a
     single-byte character set could result in spurious warnings about
     truncated data.  (Bug #25815)

   * In certain cases it could happen that deleting a row corrupted an
     `RTREE' index. This affected indexes on spatial columns.  (Bug
     #25673)

   * Expressions involving `SUM()', when used in an `ORDER BY' clause,
     could lead to out-of-order results.  (Bug #25376)

   * Use of a `GROUP BY' clause that referred to a stored function
     result together with `WITH ROLLUP' caused incorrect results.  (Bug
     #25373)

   * A stored procedure that made use of cursors failed when the
     procedure was invoked from a stored function.  (Bug #25345)

   * On Windows, the server exhibited a file-handle leak after reaching
     the limit on the number of open file descriptors.  (Bug #25222)

   * The `REPEAT()' function did not permit a column name as the COUNT
     parameter.  (Bug #25197)

   * A reference to a nonexistent column in the `ORDER BY' clause of an
     `UPDATE ... ORDER BY' statement could cause a server crash.  (Bug
     #25126)

   * A view on a join is insertable for *Note `INSERT': insert.
     statements that store values into only one table of the join.
     However, inserts were being rejected if the inserted-into table
     was used in a self-join because MySQL incorrectly was considering
     the insert to modify multiple tables of the view.  (Bug #25122)

   * MySQL would not compile when configured using
     `--without-query-cache'.  (Bug #25075)

   * IF(EXPR, UNSIGNED_EXPR, UNSIGNED_EXPR) was evaluated to a signed
     result, not unsigned. This has been corrected. The fix also
     affects constructs of the form `IS [NOT] {TRUE|FALSE}', which were
     transformed internally into `IF()' expressions that evaluated to a
     signed result.

     For existing views that were defined using `IS [NOT] {TRUE|FALSE}'
     constructs, there is a related implication. The definitions of
     such views were stored using the `IF()' expression, not the
     original construct. This is manifest in that *Note `SHOW CREATE
     VIEW': show-create-view. shows the transformed `IF()' expression,
     not the original one. Existing views will evaluate correctly after
     the fix, but if you want *Note `SHOW CREATE VIEW':
     show-create-view. to display the original construct, you must drop
     the view and re-create it using its original definition. New views
     will retain the construct in their definition.  (Bug #24532)

   * A user-defined variable could be assigned an incorrect value if a
     temporary table was employed in obtaining the result of the query
     used to determine its value.  (Bug #24010)

   * Queries that used a temporary table for the outer query when
     evaluating a correlated subquery could return incorrect results.
     (Bug #23800)

   * When using certain server SQL modes, the `mysql.proc' table was
     not created by *Note `mysql_install_db': mysql-install-db.  (Bug
     #23669)

   * *Note `DOUBLE': numeric-types. values such as
     `20070202191048.000000' were being treated as illegal arguments by
     `WEEK()'.  (Bug #23616)

   * The server could crash if two or more threads initiated query
     cache resize operation at moments very close in time.  (Bug #23527)

   * `NOW()' returned the wrong value in statements executed at server
     startup with the `--init-file' option.  (Bug #23240)

   * When nesting stored procedures within a trigger on a table, a
     false dependency error was thrown when one of the nested
     procedures contained a *Note `DROP TABLE': drop-table.  statement.
     (Bug #22580)

   * Instance Manager did not remove the angel PID file on a clean
     shutdown.  (Bug #22511)

   * *Note `EXPLAIN EXTENDED': explain. did not show `WHERE' conditions
     that were optimized away.  (Bug #22331)

   * `IN ((SUBQUERY))', `IN (((SUBQUERY)))', and so forth, are
     equivalent to `IN (SUBQUERY)', which is always interpreted as a
     table subquery (so that it is permitted to return more than one
     row). MySQL was treating the `over-parenthesized' subquery as a
     single-row subquery and rejecting it if it returned more than one
     row. This bug primarily affected automatically generated code
     (such as queries generated by Hibernate), because humans rarely
     write the over-parenthesized forms.  (Bug #21904)

   * An `INSERT' trigger invoking a stored routine that inserted into a
     table other than the one on which the trigger was defined would
     fail with a `Table '...'  doesn't exist' referring to the second
     table when attempting to delete records from the first table.
     (Bug #21825)

   * When a stored routine attempted to execute a statement accessing a
     nonexistent table, the error was not caught by the routine's
     exception handler.  (Bug #20713, Bug #8407)

   * The conditions checked by the optimizer to permit use of indexes
     in `IN' predicate calculations were unnecessarily tight and were
     relaxed.  (Bug #20420)

   * When a `TIME_FORMAT()' expression was used as a column in a `GROUP
     BY' clause, the expression result was truncated.  (Bug #20293)

   * The creation of MySQL system tables was not checked for by
     `mysql-test-run.pl'.  (Bug #20166)

   * For index reads, the `BLACKHOLE' engine did not return end-of-file
     (which it must because `BLACKHOLE' tables contain no rows), causing
     some queries to crash.  (Bug #19717)

   * For `EXPR IN(VALUE_LIST)', the result could be incorrect if
     `BIGINT UNSIGNED' values were used for EXPR or in the value list.
     (Bug #19342)

   * When attempting to call a stored procedure creating a table from a
     trigger on a table `tbl' in a database `db', the trigger failed
     with `ERROR 1146 (42S02): Table 'db.tbl' doesn't exist'. However,
     the actual reason that such a trigger fails is due to the fact
     that *Note `CREATE TABLE': create-table. causes an implicit *Note
     `COMMIT': commit, and so a trigger cannot invoke a stored routine
     containing this statement. A trigger which does so now fails with
     `ERROR 1422 (HY000): Explicit or implicit commit is not permitted
     in stored function or trigger', which makes clear the reason for
     the trigger's failure.  (Bug #18914)

   * The update columns for `INSERT ... SELECT ... ON DUPLICATE KEY
     UPDATE' could be assigned incorrect values if a temporary table
     was used to evaluate the *Note `SELECT': select.  (Bug #16630)

   * For `SUBSTRING()' evaluation using a temporary table, when
     `SUBSTRING()' was used on a LONGTEXT column, the `max_length'
     metadata value of the result was incorrectly calculated and set to
     0.  Consequently, an empty string was returned instead of the
     correct result.  (Bug #15757)

   * Local variables in stored routines or triggers, when declared as
     the *Note `BIT': numeric-types. type, were interpreted as strings.
     (Bug #12976)

   * `CONNECTION' is no longer treated as a reserved word.  (Bug #12204)


File: manual.info,  Node: news-5-0-37,  Next: news-5-0-36sp1,  Prev: news-5-0-38,  Up: news-5-0-x

D.1.59 Changes in MySQL Community Server 5.0.37 (27 February 2007)
------------------------------------------------------------------

This is a bugfix release for the current MySQL Community Server
production release family. It replaces MySQL 5.0.33.

*Functionality Added or Changed*

   * *Incompatible Change*: *MySQL Cluster*: The `LockPagesInMainMemory'
     configuration parameter has changed its type and possible values.

     *Important*:

     The values `true' and `false' are no longer accepted for this
     parameter. If you were using this parameter and had it set to
     `false' in a previous release, you must change it to `0'. If you
     had this parameter set to `true', you should instead use `1' to
     obtain the same behavior as previously, or `2' to take advantage
     of new functionality introduced with this release, as described in
     the section cited above.

     (Bug #25686)

   * *Incompatible Change*: Previously, the `DATE_FORMAT()' function
     returned a binary string. Now it returns a string with a character
     set and collation given by `character_set_connection' and
     `collation_connection' so that it can return month and weekday
     names containing non-ASCII characters.  (Bug #22646)

   * *Important Change*: When using a `MERGE' table, the definition of
     the table and the underlying `MyISAM' tables are checked each time
     the tables are opened for access (including any *Note `SELECT':
     select. or *Note `INSERT': insert. statement). Each table is
     compared for column order, types, sizes, and associated indexes.
     If there is a difference in any one of the tables, the statement
     will fail.

   * Added the `Uptime_since_flush_status' status variable, which
     indicates the number of seconds since the most recent `FLUSH
     STATUS' statement.  (Community contribution by Jeremy Cole) (Bug
     #24822)

   * Added the *Note `SHOW PROFILES': show-profiles. and *Note `SHOW
     PROFILE': show-profile. statements to display statement profile
     data, and the accompanying *Note `INFORMATION_SCHEMA.PROFILING':
     profiling-table. table.  Profiling is controlled using the
     `profiling' and `profiling_history_size' session variables. see
     *Note show-profiles::, and *Note profiling-table::. (Community
     contribution by Jeremy Cole)

     The profiling feature is enabled using the
     `--enable-community-features'
     (http://dev.mysql.com/doc/refman/5.1/en/source-configuration-options.html#option_configure_enable-community-features)
     and `--enable-profiling' options to `configure'. These options are
     enabled by default; to disable them, use
     `--disable-community-features'
     (http://dev.mysql.com/doc/refman/5.1/en/source-configuration-options.html#option_configure_enable-community-features)
     and `--disable-profiling'.  (Bug #24795)

   * The `localhost' anonymous user account created during MySQL
     installation on Windows now has no global privileges. Formerly
     this account had all global privileges. For operations that
     require global privileges, the `root' account can be used instead.
     (Bug #24496)

   * The `--skip-thread-priority' option now is enabled by default for
     binary Mac OS X distributions. Use of thread priorities degrades
     performance on Mac OS X.  (Bug #18526)

   * This is the last version for which MySQL-Max RPM distributions are
     available. (This change was already made for non-RPM binary
     distributions in 5.0.27.)

   * The bundled yaSSL library was upgraded to version 1.5.8.

   * Added the `--disable-grant-options' option to `configure'. If
     `configure' is run with this option, the `--bootstrap',
     `--skip-grant-tables', and `--init-file' options for *Note
     `mysqld': mysqld. are disabled and cannot be used. For Windows,
     the `configure.js' script recognizes the `DISABLE_GRANT_OPTIONS'
     flag, which has the same effect.

*Bugs Fixed*

   * *Security Fix*: Using an `INFORMATION_SCHEMA' table with `ORDER
     BY' in a subquery could cause a server crash.

     We would like to thank Oren Isacson of Flowgate Security
     Consulting and Stefan Streichsbier of SEC Consult for informing us
     of this problem.  (Bug #24630, Bug #26556, CVE-2007-1420)

   * *Incompatible Change*: For *Note `ENUM': enum. columns that had
     enumeration values containing commas, the commas were mapped to
     `0xff' internally. However, this rendered the commas
     indistinguishable from true `0xff' characters in the values. This
     no longer occurs. However, the fix requires that you dump and
     reload any tables that have *Note `ENUM': enum. columns containing
     any true `0xff' values. Dump the tables using *Note `mysqldump':
     mysqldump. with the current server before upgrading from a version
     of MySQL 5.0 older than 5.0.36 to version 5.0.36 or newer.  (Bug
     #24660)

   * *Partitioning*: *MySQL Cluster*: A query with an `IN' clause
     against an *Note `NDB': mysql-cluster. table employing explicit
     user-defined partitioning did not always return all matching rows.
     (Bug #25821)

   * *MySQL Cluster*: It was not possible to create an *Note `NDB':
     mysql-cluster. table with a key on two *Note `VARCHAR': char.
     columns where both columns had a storage length in excess of 256.
     (Bug #25746)

   * *MySQL Cluster*: Hosts in clusters with large numbers of nodes
     could experience excessive CPU usage while obtaining configuration
     data.  (Bug #25711)

   * *MySQL Cluster*: In some circumstances, shutting down the cluster
     could cause connected *Note `mysqld': mysqld. processes to crash.
     (Bug #25668)

   * *MySQL Cluster*: Memory allocations for *Note `TEXT': blob.
     columns were calculated incorrectly, resulting in space being
     wasted and other issues.  (Bug #25562)

   * *MySQL Cluster*: The failure of a master node during a node
     restart could lead to a resource leak, causing later node failures.
     (Bug #25554)

   * *MySQL Cluster*: An *Note `UPDATE': update. using an `IN' clause
     on an *Note `NDB': mysql-cluster. table on which there was a
     trigger caused *Note `mysqld': mysqld. to crash.  (Bug #25522)

   * *MySQL Cluster*: A node shutdown occurred if the master failed
     during a commit.  (Bug #25364)

   * *MySQL Cluster*: Creating a nonunique index with the `USING HASH'
     clause silently created an ordered index instead of issuing a
     warning.  (Bug #24820)

   * *MySQL Cluster*: The `ndb_size.tmpl' file (necessary for using the
     `ndb_size.pl' script) was missing from binary distributions.  (Bug
     #24191)

   * *MySQL Cluster*: When a data node was shut down using the
     management client `STOP' command, a connection event
     (`NDB_LE_Connected') was logged instead of a disconnection event
     (`NDB_LE_Disconnected').  (Bug #22773)

   * *MySQL Cluster*: The management server did not handle logging of
     node shutdown events correctly in certain cases.  (Bug #22013)

   * *MySQL Cluster*: *Note `SELECT': select. statements with a *Note
     `BLOB': blob. or *Note `TEXT': blob. column in the selected column
     list and a `WHERE' condition including a primary key lookup on a
     *Note `VARCHAR': char.  primary key produced empty result sets.
     (Bug #19956)

   * *Replication*: When *Note `SET PASSWORD': set-password. was
     written to the binary log, double quotation marks were included in
     the statement. If the slave was running in with the server SQL mode
     set to `ANSI_QUOTES', then the event failed, which halted the
     replication process.  (Bug #24158)

   * *Replication*: A stored procedure, executed from a connection
     using a binary character set, and which wrote multibyte data,
     would write incorrectly escaped entries to the binary log. This
     caused syntax errors, and caused replication to fail.  (Bug
     #23619, Bug #24492)

   * *Replication*: Changes to the `lc_time_names' system variable were
     not replicated.  (Bug #22645)

   * *Replication*: For *Note `SET': set-option, *Note `SELECT':
     select, and *Note `DO': do. statements that invoked a stored
     function from a database other than the default database, the
     function invocation could fail to be replicated.  (Bug #19725)

   * *Replication*: If a slave server closed its relay log (for
     example, due to an error during log rotation), the I/O thread did
     not recognize this and still tried to write to the log, causing a
     server crash.  (Bug #10798)

   * *Cluster API*: Deletion of an `Ndb_cluster_connection' object took
     a very long time.  (Bug #25487)

   * *Cluster API*: Invoking the `NdbTransaction::execute()' method
     using execution type `Commit' and abort option `AO_IgnoreError'
     could lead to a crash of the transaction coordinator (`DBTC').
     (Bug #25090)

   * *Cluster API*: A unique index lookup on a nonexistent tuple could
     lead to a data node timeout (error 4012).  (Bug #25059)

   * *Cluster API*: `libndbclient.so' was not versioned.  (Bug #13522)

   * Using `ORDER BY' or `GROUP BY' could yield different results when
     selecting from a view and selecting from the underlying table.
     (Bug #26209)

   * `DISTINCT' queries that were executed using a loose scan for an
     `InnoDB' table that had been emptied caused a server crash.  (Bug
     #26159)

   * A `WHERE' clause that used `BETWEEN' for *Note `DATETIME':
     datetime. values could be treated differently for a *Note
     `SELECT': select. and a view defined as that *Note `SELECT':
     select.  (Bug #26124)

   * Collation for `LEFT JOIN' comparisons could be evaluated
     incorrectly, leading to improper query results.  (Bug #26017)

   * The `WITH CHECK OPTION' clause for views was ignored for updates
     of multiple-table views when the updates could not be performed on
     fly and the rows to update had to be put into temporary tables
     first.  (Bug #25931)

   * *Note `LOAD DATA INFILE': load-data. did not work with pipes.
     (Bug #25807)

   * The `SEC_TO_TIME()' and `QUARTER()' functions sometimes did not
     handle `NULL' values correctly.  (Bug #25643)

   * The `InnoDB' parser sometimes did not account for null bytes,
     causing spurious failure of some queries.  (Bug #25596)

   * View definitions that used the `!' operator were treated as
     containing the `NOT' operator, which has a different precedence
     and can produce different results. .  (Bug #25580)

   * An error in the name resolution of nested `JOIN ...  USING'
     constructs was corrected.  (Bug #25575)

   * `GROUP BY' and `DISTINCT' did not group `NULL' values for columns
     that have a `UNIQUE' index. .  (Bug #25551)

   * The `--with-readline' option for `configure' did not work for
     commercial source packages, but no error message was printed to
     that effect. Now a message is printed.  (Bug #25530)

   * *Note `mysql_stmt_fetch()': mysql-stmt-fetch. did an invalid
     memory deallocation when used with the embedded server.  (Bug
     #25492)

   * Referencing an ambiguous column alias in an expression in the
     `ORDER BY' clause of a query caused the server to crash.  (Bug
     #25427)

   * A yaSSL program named `test' was installed, causing conflicts with
     the `test' system utility. It is no longer installed.  (Bug #25417)

   * For a `UNIQUE' index containing many `NULL' values, the optimizer
     would prefer the index for `COL IS NULL' conditions over other
     more selective indexes. .  (Bug #25407)

   * An `AFTER UPDATE' trigger on an `InnoDB' table with a composite
     primary key caused the server to crash.  (Bug #25398)

   * Passing a `NULL' value to a user-defined function from within a
     stored procedure crashes the server.  (Bug #25382)

   * *Note `perror': perror. crashed on some platforms due to failure
     to handle a `NULL' pointer.  (Bug #25344)

   * *Note `mysql.server stop': mysql-server. timed out too quickly (35
     seconds) waiting for the server to exit. Now it waits up to 15
     minutes, to ensure that the server exits.  (Bug #25341)

   * A query that contained an `EXIST' subquery with a *Note `UNION':
     union. over correlated and uncorrelated *Note `SELECT': select.
     queries could cause the server to crash.  (Bug #25219)

   * *Note `mysql_kill()': mysql-kill. caused a server crash when used
     on an SSL connection.  (Bug #25203)

   * yaSSL was sensitive to the presence of whitespace at the ends of
     lines in PEM-encoded certificates, causing a server crash.  (Bug
     #25189)

   * A query with `ORDER BY' and `GROUP BY' clauses where the `ORDER BY'
     clause had more elements than the `GROUP BY' clause caused a
     memory overrun leading to a crash of the server.  (Bug #25172)

   * Use of `ON DUPLICATE KEY UPDATE' defeated the usual restriction
     against inserting into a join-based view unless only one of the
     underlying tables is used.  (Bug #25123)

   * Using a view in combination with a `USING' clause caused column
     aliases to be ignored.  (Bug #25106)

   * A multiple-table *Note `DELETE QUICK': delete. could sometimes
     cause one of the affected tables to become corrupted.  (Bug #25048)

   * `ALTER TABLE ... ENABLE KEYS' acquired a global lock, preventing
     concurrent execution of other statements that use tables. .  (Bug
     #25044)

   * An assertion failed incorrectly for prepared statements that
     contained a single-row uncorrelated subquery that was used as an
     argument of the `IS NULL' predicate.  (Bug #25027)

   * A return value of `-1' from user-defined handlers was not handled
     well and could result in conflicts with server code.  (Bug #24987)

   * Accessing a fixed record format table with a crashed key
     definition results in server/*Note `myisamchk': myisamchk.
     segmentation fault.  (Bug #24855)

   * *Note `mysqld_multi': mysqld-multi. and *Note `mysqlaccess':
     mysqlaccess. looked for option files in `/etc' even if the
     `--sysconfdir' option for `configure' had been given to specify a
     different directory.  (Bug #24780)

   * If there was insufficient memory available to *Note `mysqld':
     mysqld, this could sometimes cause the server to hang during
     startup.  (Bug #24751)

   * Optimizations that are legal only for subqueries without tables
     and `WHERE' conditions were applied for any subquery without
     tables.  (Bug #24670)

   * If an `ORDER BY' or `GROUP BY' list included a constant expression
     being optimized away and, at the same time, containing single-row
     subselects that returned more that one row, no error was reported.
     If a query required sorting by expressions containing single-row
     subselects that returned more than one row, execution of the query
     could cause a server crash.  (Bug #24653)

   * For *Note `ALTER TABLE': alter-table, using `ORDER BY EXPRESSION'
     could cause a server crash. Now the `ORDER BY' clause permits only
     column names to be specified as sort criteria (which was the only
     documented syntax, anyway).  (Bug #24562)

   * A workaround was implemented to avoid a race condition in the NPTL
     `pthread_exit()' implementation.  (Bug #24507)

   * `mysqltest' crashed with a stack overflow.  (Bug #24498)

   * Within stored routines or prepared statements, inconsistent
     results occurred with multiple use of `INSERT ... SELECT ... ON
     DUPLICATE KEY UPDATE' when the `ON DUPLICATE KEY UPDATE' clause
     erroneously tried to assign a value to a column mentioned only in
     its *Note `SELECT': select. part.  (Bug #24491)

   * Expressions of the form `(a, b) IN (SELECT a, MIN(b) FROM t GROUP
     BY a)' could produce incorrect results when column `a' of table `t'
     contained `NULL' values while column `b' did not.  (Bug #24420)

   * If a prepared statement accessed a view, access to the tables
     listed in the query after that view was checked in the security
     context of the view.  (Bug #24404)

   * Attempts to access a `MyISAM' table with a corrupt column
     definition caused a server crash.  (Bug #24401)

   * When opening a corrupted `.frm' file during a query, the server
     crashes.  (Bug #24358)

   * Some joins in which one of the joined tables was a view could
     return erroneous results or crash the server.  (Bug #24345)

   * A view was not handled correctly if the *Note `SELECT': select.
     part contained ``\Z''.  (Bug #24293)

   * A query using `WHERE UNSIGNED_COLUMN NOT IN ('NEGATIVE_VALUE')'
     could cause the server to crash.  (Bug #24261)

   * Expressions of the form `(a, b) IN (SELECT c, d ...)' could
     produce incorrect results if `a', `b', or both were `NULL'.  (Bug
     #24127)

   * A *Note `FETCH': fetch. statement using a cursor on a table which
     was not in the table cache could sometimes cause the server to
     crash.  (Bug #24117)

   * Queries that evaluate `NULL IN (SELECT ... UNION SELECT ...)'
     could produce an incorrect result (`FALSE' instead of `NULL').
     (Bug #24085)

   * Hebrew-to-Unicode conversion failed for some characters.
     Definitions for the following Hebrew characters (as specified by
     the ISO/IEC 8859-8:1999) were added: LEFT-TO-RIGHT MARK (LRM),
     RIGHT-TO-LEFT MARK (RLM) (Bug #24037)

   * Some *Note `UPDATE': update. statements were slower than in
     previous versions when the search key could not be converted to a
     valid value for the type of the search column.  (Bug #24035)

   * `ISNULL(DATE(NULL))' and `ISNULL(CAST(NULL AS DATE))' erroneously
     returned false.  (Bug #23938)

   * Within a stored routine, accessing a declared routine variable
     with `PROCEDURE ANALYSE()' caused a server crash.  (Bug #23782)

   * When reading from the standard input on Windows, *Note
     `mysqlbinlog': mysqlbinlog. opened the input in text mode rather
     than binary mode and consequently misinterpreted some characters
     such as `Control+Z'.  (Bug #23735)

   * *Note `OPTIMIZE TABLE': optimize-table. tried to sort R-tree
     indexes such as spatial indexes, although this is not possible
     (see *Note optimize-table::).  (Bug #23578)

   * For an `InnoDB' table with any `ON DELETE' trigger, *Note
     `TRUNCATE TABLE': truncate-table. mapped to *Note `DELETE': delete.
     and activated triggers. Now a fast truncation occurs and triggers
     are not activated. .  (Bug #23556)

   * The row count for `MyISAM' tables was not updated properly,
     causing *Note `SHOW TABLE STATUS': show-table-status. to report
     incorrect values.  (Bug #23526)

   * User-defined variables could consume excess memory, leading to a
     crash caused by the exhaustion of resources available to the
     `MEMORY' storage engine, due to the fact that this engine is used
     by MySQL for variable storage and intermediate results of `GROUP
     BY' queries.  Where *Note `SET': set-option.  had been used, such
     a condition could instead give rise to the misleading error
     message `You may only use constant expressions with SET', rather
     than `Out of memory (Needed NNNNNN bytes)'.  (Bug #23443)

   * With `ONLY_FULL_GROUP_BY' enabled, the server was too strict: Some
     expressions involving only aggregate values were rejected as
     nonaggregate (for example, `MAX(a)' - `MIN(a)').  (Bug #23417)

   * The arguments to the `ENCODE()' and the `DECODE()' functions were
     not printed correctly, causing problems in the output of *Note
     `EXPLAIN EXTENDED': explain. and in view definitions.  (Bug #23409)

   * A table created with the `ROW_FORMAT = FIXED' table option lost
     that option if an index was added or dropped with *Note `CREATE
     INDEX': create-index. or *Note `DROP INDEX': drop-index.  (Bug
     #23404)

   * A deadlock could occur, with the server hanging on `Closing
     tables', with a sufficient number of concurrent *Note `INSERT
     DELAYED': insert-delayed, *Note `FLUSH TABLES': flush, and *Note
     `ALTER TABLE': alter-table. operations.  (Bug #23312)

   * Some queries against `INFORMATION_SCHEMA' that used subqueries
     failed. .  (Bug #23299)

   * `readline' detection did not work correctly on NetBSD.  (Bug
     #23293)

   * If there was insufficient memory to store or update a blob record
     in a `MyISAM' table then the table will marked as crashed.  (Bug
     #23196)

   * `LAST_INSERT_ID()' was not reset to 0 if *Note `INSERT ...
     SELECT': insert-select. inserted no rows.  (Bug #23170)

   * A compressed `MyISAM' table that became corrupted could crash
     *Note `myisamchk': myisamchk. and possibly the MySQL Server.  (Bug
     #23139)

   * The number of `setsockopt()' calls performed for reads and writes
     to the network socket was reduced to decrease system call overhead.
     (Bug #22943)

   * *Note `mysql_upgrade': mysql-upgrade. failed when called with a
     `--basedir' path name containing spaces.  (Bug #22801)

   * `SET lc_time_names = VALUE ' permitted only exact literal values,
     not expression values.  (Bug #22647)

   * The `STDDEV()' function returned a positive value for data sets
     consisting of a single value.  (Bug #22555)

   * Storing values specified as hexadecimal values 64 or more bits
     long in `BIT(64)', *Note `BIGINT': numeric-types, or `BIGINT
     UNSIGNED' columns did not raise any warning or error if the value
     was out of range.  (Bug #22533)

   * *Note `SHOW COLUMNS': show-columns. reported some `NOT NULL'
     columns as `NULL'.  (Bug #22377)

   * Type conversion errors during formation of index search conditions
     were not correctly checked, leading to incorrect query results.
     (Bug #22344)

   * Changing the value of `MI_KEY_BLOCK_LENGTH' in `myisam.h' and
     recompiling MySQL resulted in a *Note `myisamchk': myisamchk. that
     saw existing `MyISAM' tables as corrupt.  (Bug #22119)

   * A crash of the MySQL Server could occur when unpacking a *Note
     `BLOB': blob. column from a row in a corrupted MyISAM table. This
     could happen when trying to repair a table using either *Note
     `REPAIR TABLE': repair-table.  or *Note `myisamchk': myisamchk.;
     it could also happen when trying to access such a `broken' row
     using statements like *Note `SELECT': select. if the table was not
     marked as crashed.  (Bug #22053)

   * The code for generating *Note `USE': use.  statements for binary
     logging of *Note `CREATE PROCEDURE': create-procedure. statements
     resulted in confusing output from *Note `mysqlbinlog':
     mysqlbinlog. for *Note `DROP PROCEDURE': drop-procedure.
     statements.  (Bug #22043)

   * For the `IF()' and `COALESCE()' function and `CASE' expressions,
     large unsigned integer values could be mishandled and result in
     warnings.  (Bug #22026)

   * SSL connections could hang at connection shutdown.  (Bug #21781,
     Bug #24148)

   * The `FEDERATED' storage engine did not support the `euckr'
     character set.  (Bug #21556)

   * When updating a table that used a `JOIN' of the table itself (for
     example, when building trees) and the table was modified on one
     side of the expression, the table would either be reported as
     crashed or the wrong rows in the table would be updated.  (Bug
     #21310)

   * `mysqld_error.h' was not installed when only the client libraries
     were built.  (Bug #21265)

   * `InnoDB': During a restart of the MySQL Server that followed the
     creation of a temporary table using the `InnoDB' storage engine,
     MySQL failed to clean up in such a way that `InnoDB' still
     attempted to find the files associated with such tables.  (Bug
     #20867)

   * Inserting `DEFAULT' into a column with no default value could
     result in garbage in the column. Now the same result occurs as
     when inserting `NULL' into a `NOT NULL' column.  (Bug #20691)

   * A stored routine containing semicolon in its body could not be
     reloaded from a dump of a binary log.  (Bug #20396)

   * *Note `SELECT ... FOR UPDATE': select, *Note `SELECT ... LOCK IN
     SHARE MODE': select, *Note `DELETE': delete, and *Note `UPDATE':
     update. statements executed using a full table scan were not
     releasing locks on rows that did not satisfy the `WHERE' condition.
     (Bug #20390)

   * On Windows, if the server was installed as a service, it did not
     auto-detect the location of the data directory.  (Bug #20376)

   * The `BUILD/check-cpu' script did not recognize Celeron processors.
     (Bug #20061)

   * If a duplicate key value was present in the table, *Note `INSERT
     ... ON DUPLICATE KEY UPDATE': insert-on-duplicate. reported a row
     count indicating that a record was updated, even when no record
     actually changed due to the old and new values being the same.
     Now it reports a row count of zero.  (Bug #19978) See also Bug
     #27006, Bug #27033, Bug #27210.

   * `ORDER BY' values of the *Note `DOUBLE': numeric-types. or *Note
     `DECIMAL': numeric-types. types could change the result returned
     by a query.  (Bug #19690)

   * The `readline' library wrote to uninitialized memory, causing
     *Note `mysql': mysql. to crash.  (Bug #19474)

   * `mysqltest' incorrectly tried to retrieve result sets for some
     queries where no result set was available.  (Bug #19410)

   * Use of already freed memory caused SSL connections to hang forever.
     (Bug #19209)

   * Some *Note `CASE': case-statement.  statements inside stored
     routines could lead to excessive resource usage or a crash of the
     server.  (Bug #19194, Bug #24854)

   * Instance Manager could crash during shutdown.  (Bug #19044)

   * The server might fail to use an appropriate index for *Note
     `DELETE': delete. when `ORDER BY', `LIMIT', and a nonrestricting
     `WHERE' are present.  (Bug #17711)

   * No warning was issued for use of the `DATA DIRECTORY' or `INDEX
     DIRECTORY' table options on a platform that does not support them.
     (Bug #17498)

   * The `FEDERATED' storage engine did not support the `utf8'
     character set.  (Bug #17044)

   * The optimizer removes expressions from `GROUP BY' and `DISTINCT'
     clauses if they happen to participate in ` EXPRESSION = CONSTANT'
     predicates of the `WHERE' clause, the idea being that, if the
     expression is equal to a constant, then it cannot take on multiple
     values. However, for predicates where the expression and the
     constant item are of different result types (for example, when a
     string column is compared to 0), this is not valid, and can lead
     to invalid results in such cases. The optimizer now performs an
     additional check of the result types of the expression and the
     constant; if their types differ, then the expression is not
     removed from the `GROUP BY' list.  (Bug #15881)

   * When a prepared statement failed during the prepare operation, the
     error code was not cleared when it was reused, even if the
     subsequent use was successful.  (Bug #15518)

   * Dropping a user-defined function sometimes did not remove the UDF
     entry from the `mysql.proc' table.  (Bug #15439)

   * Inserting a row into a table without specifying a value for a
     `BINARY(N) NOT NULL' column caused the column to be set to spaces,
     not zeros.  (Bug #14171)

   * On Windows, the `SLEEP()' function could sleep too long,
     especially after a change to the system clock.  (Bug #14094, Bug
     #24686, Bug #17635)

   * *Note `mysqldump --order-by-primary': mysqldump. failed if the
     primary key name was an identifier that required quoting.  (Bug
     #13926)

   * To enable installation of MySQL RPMs on Linux systems running RHEL
     4 (which includes SE-Linux) additional information was provided to
     specify some actions that are permitted to the MySQL binaries.
     (Bug #12676)

   * The presence of `ORDER BY' in a view definition prevented the
     `MERGE' algorithm from being used to resolve the view even if
     nothing else in the definition required the `TEMPTABLE' algorithm.
     (Bug #12122)

   * The internal functions for table preparation, creation, and
     alteration were not re-execution friendly, causing problems in
     code that: repeatedly altered a table; repeatedly created and
     dropped a table; opened and closed a cursor on a table, altered
     the table, and then reopened the cursor; used *Note `ALTER TABLE':
     alter-table. to change a table's current `AUTO_INCREMENT' value;
     created indexes on `utf8' columns.

     Re-execution of *Note `CREATE DATABASE': create-database, *Note
     `CREATE TABLE': create-table, and *Note `ALTER TABLE':
     alter-table. statements in stored routines or as prepared
     statements also caused incorrect results or crashes.  (Bug #4968,
     Bug #6895, Bug #19182, Bug #19733, Bug #22060, Bug #24879)


File: manual.info,  Node: news-5-0-36sp1,  Next: news-5-0-36,  Prev: news-5-0-37,  Up: news-5-0-x

D.1.60 Changes in MySQL Enterprise 5.0.36sp1 [QSP] (12 April 2007)
------------------------------------------------------------------

This is a _Service Pack_ release of the MySQL Enterprise Server 5.0.

This section documents all changes and bug fixes that have been applied
since the last MySQL Enterprise Server release (5.0.36).

*Bugs Fixed*

   * *Note `SELECT ... INTO OUTFILE': select. with a long `FIELDS
     ENCLOSED BY' value could crash the server.  (Bug #27231)

   * For `MERGE' tables defined on underlying tables that contained a
     short *Note `VARCHAR': char.  column (shorter than four
     characters), using *Note `ALTER TABLE': alter-table. on at least
     one but not all of the underlying tables caused the table
     definitions to be considered different from that of the `MERGE'
     table, even if the *Note `ALTER TABLE': alter-table. did not
     change the definition.  (Bug #26881)


File: manual.info,  Node: news-5-0-36,  Next: news-5-0-34,  Prev: news-5-0-36sp1,  Up: news-5-0-x

D.1.61 Changes in MySQL Enterprise 5.0.36 [MRU] (20 February 2007)
------------------------------------------------------------------

This is a _Monthly Rapid Update_ release of the MySQL Enterprise Server
5.0.

*Note*:

After release, a trigger failure problem was found to have been
introduced. (Bug #27006) Users affected by this issue should upgrade to
MySQL 5.0.38, which corrects the problem.

This section documents all changes and bug fixes that have been applied
since the last MySQL Enterprise Server release (5.0.34).

*Functionality Added or Changed*

   * *Incompatible Change*: *MySQL Cluster*: The `LockPagesInMainMemory'
     configuration parameter has changed its type and possible values.

     *Important*:

     The values `true' and `false' are no longer accepted for this
     parameter. If you were using this parameter and had it set to
     `false' in a previous release, you must change it to `0'. If you
     had this parameter set to `true', you should instead use `1' to
     obtain the same behavior as previously, or `2' to take advantage
     of new functionality introduced with this release, as described in
     the section cited above.

     (Bug #25686)

   * *Incompatible Change*: Previously, the `DATE_FORMAT()' function
     returned a binary string. Now it returns a string with a character
     set and collation given by `character_set_connection' and
     `collation_connection' so that it can return month and weekday
     names containing non-ASCII characters.  (Bug #22646)

   * *Important Change*: When using a `MERGE' table, the definition of
     the table and the underlying `MyISAM' tables are checked each time
     the tables are opened for access (including any *Note `SELECT':
     select. or *Note `INSERT': insert. statement). Each table is
     compared for column order, types, sizes, and associated indexes.
     If there is a difference in any one of the tables, the statement
     will fail.

   * The `localhost' anonymous user account created during MySQL
     installation on Windows now has no global privileges. Formerly
     this account had all global privileges. For operations that
     require global privileges, the `root' account can be used instead.
     (Bug #24496)

   * The bundled yaSSL library was upgraded to version 1.5.8.

*Bugs Fixed*

   * *Security Fix*: Using an `INFORMATION_SCHEMA' table with `ORDER
     BY' in a subquery could cause a server crash.

     We would like to thank Oren Isacson of Flowgate Security
     Consulting and Stefan Streichsbier of SEC Consult for informing us
     of this problem.  (Bug #24630, Bug #26556, CVE-2007-1420)

   * *Incompatible Change*: For *Note `ENUM': enum. columns that had
     enumeration values containing commas, the commas were mapped to
     `0xff' internally. However, this rendered the commas
     indistinguishable from true `0xff' characters in the values. This
     no longer occurs. However, the fix requires that you dump and
     reload any tables that have *Note `ENUM': enum. columns containing
     any true `0xff' values. Dump the tables using *Note `mysqldump':
     mysqldump. with the current server before upgrading from a version
     of MySQL 5.0 older than 5.0.36 to version 5.0.36 or newer.  (Bug
     #24660)

   * *Partitioning*: *MySQL Cluster*: A query with an `IN' clause
     against an *Note `NDB': mysql-cluster. table employing explicit
     user-defined partitioning did not always return all matching rows.
     (Bug #25821)

   * *MySQL Cluster*: It was not possible to create an *Note `NDB':
     mysql-cluster. table with a key on two *Note `VARCHAR': char.
     columns where both columns had a storage length in excess of 256.
     (Bug #25746)

   * *MySQL Cluster*: In some circumstances, shutting down the cluster
     could cause connected *Note `mysqld': mysqld. processes to crash.
     (Bug #25668)

   * *MySQL Cluster*: Memory allocations for *Note `TEXT': blob.
     columns were calculated incorrectly, resulting in space being
     wasted and other issues.  (Bug #25562)

   * *MySQL Cluster*: The failure of a master node during a node
     restart could lead to a resource leak, causing later node failures.
     (Bug #25554)

   * *MySQL Cluster*: An *Note `UPDATE': update. using an `IN' clause
     on an *Note `NDB': mysql-cluster. table on which there was a
     trigger caused *Note `mysqld': mysqld. to crash.  (Bug #25522)

   * *MySQL Cluster*: A node shutdown occurred if the master failed
     during a commit.  (Bug #25364)

   * *MySQL Cluster*: Creating a nonunique index with the `USING HASH'
     clause silently created an ordered index instead of issuing a
     warning.  (Bug #24820)

   * *MySQL Cluster*: The `ndb_size.tmpl' file (necessary for using the
     `ndb_size.pl' script) was missing from binary distributions.  (Bug
     #24191)

   * *MySQL Cluster*: The management server did not handle logging of
     node shutdown events correctly in certain cases.  (Bug #22013)

   * *MySQL Cluster*: *Note `SELECT': select. statements with a *Note
     `BLOB': blob. or *Note `TEXT': blob. column in the selected column
     list and a `WHERE' condition including a primary key lookup on a
     *Note `VARCHAR': char.  primary key produced empty result sets.
     (Bug #19956)

   * *MySQL Cluster*: The loss of one or more data nodes could
     sometimes cause *Note `ndb_mgmd': mysql-cluster-programs-ndb-mgmd.
     to use a high amount of CPU (15 percent or more, as opposed to 1
     to 2 percent normally).

   * *Replication*: When *Note `SET PASSWORD': set-password. was
     written to the binary log, double quotation marks were included in
     the statement. If the slave was running in with the server SQL mode
     set to `ANSI_QUOTES', then the event failed, which halted the
     replication process.  (Bug #24158)

   * *Replication*: A stored procedure, executed from a connection
     using a binary character set, and which wrote multibyte data,
     would write incorrectly escaped entries to the binary log. This
     caused syntax errors, and caused replication to fail.  (Bug
     #23619, Bug #24492)

   * *Replication*: Changes to the `lc_time_names' system variable were
     not replicated.  (Bug #22645)

   * *Replication*: For *Note `SET': set-option, *Note `SELECT':
     select, and *Note `DO': do. statements that invoked a stored
     function from a database other than the default database, the
     function invocation could fail to be replicated.  (Bug #19725)

   * *Replication*: If a slave server closed its relay log (for
     example, due to an error during log rotation), the I/O thread did
     not recognize this and still tried to write to the log, causing a
     server crash.  (Bug #10798)

   * *Cluster API*: Deletion of an `Ndb_cluster_connection' object took
     a very long time.  (Bug #25487)

   * *Cluster API*: `libndbclient.so' was not versioned.  (Bug #13522)

   * Using `ORDER BY' or `GROUP BY' could yield different results when
     selecting from a view and selecting from the underlying table.
     (Bug #26209)

   * `DISTINCT' queries that were executed using a loose scan for an
     `InnoDB' table that had been emptied caused a server crash.  (Bug
     #26159)

   * A `WHERE' clause that used `BETWEEN' for *Note `DATETIME':
     datetime. values could be treated differently for a *Note
     `SELECT': select. and a view defined as that *Note `SELECT':
     select.  (Bug #26124)

   * Collation for `LEFT JOIN' comparisons could be evaluated
     incorrectly, leading to improper query results.  (Bug #26017)

   * The `WITH CHECK OPTION' clause for views was ignored for updates
     of multiple-table views when the updates could not be performed on
     fly and the rows to update had to be put into temporary tables
     first.  (Bug #25931)

   * *Note `LOAD DATA INFILE': load-data. did not work with pipes.
     (Bug #25807)

   * The `SEC_TO_TIME()' and `QUARTER()' functions sometimes did not
     handle `NULL' values correctly.  (Bug #25643)

   * The `InnoDB' parser sometimes did not account for null bytes,
     causing spurious failure of some queries.  (Bug #25596)

   * View definitions that used the `!' operator were treated as
     containing the `NOT' operator, which has a different precedence
     and can produce different results. .  (Bug #25580)

   * An error in the name resolution of nested `JOIN ...  USING'
     constructs was corrected.  (Bug #25575)

   * `GROUP BY' and `DISTINCT' did not group `NULL' values for columns
     that have a `UNIQUE' index. .  (Bug #25551)

   * The `--with-readline' option for `configure' did not work for
     commercial source packages, but no error message was printed to
     that effect. Now a message is printed.  (Bug #25530)

   * A yaSSL program named `test' was installed, causing conflicts with
     the `test' system utility. It is no longer installed.  (Bug #25417)

   * For a `UNIQUE' index containing many `NULL' values, the optimizer
     would prefer the index for `COL IS NULL' conditions over other
     more selective indexes. .  (Bug #25407)

   * An `AFTER UPDATE' trigger on an `InnoDB' table with a composite
     primary key caused the server to crash.  (Bug #25398)

   * Passing a `NULL' value to a user-defined function from within a
     stored procedure crashes the server.  (Bug #25382)

   * *Note `perror': perror. crashed on some platforms due to failure
     to handle a `NULL' pointer.  (Bug #25344)

   * *Note `mysql.server stop': mysql-server. timed out too quickly (35
     seconds) waiting for the server to exit. Now it waits up to 15
     minutes, to ensure that the server exits.  (Bug #25341)

   * A query that contained an `EXIST' subquery with a *Note `UNION':
     union. over correlated and uncorrelated *Note `SELECT': select.
     queries could cause the server to crash.  (Bug #25219)

   * *Note `mysql_kill()': mysql-kill. caused a server crash when used
     on an SSL connection.  (Bug #25203)

   * yaSSL was sensitive to the presence of whitespace at the ends of
     lines in PEM-encoded certificates, causing a server crash.  (Bug
     #25189)

   * A query with `ORDER BY' and `GROUP BY' clauses where the `ORDER BY'
     clause had more elements than the `GROUP BY' clause caused a
     memory overrun leading to a crash of the server.  (Bug #25172)

   * Use of `ON DUPLICATE KEY UPDATE' defeated the usual restriction
     against inserting into a join-based view unless only one of the
     underlying tables is used.  (Bug #25123)

   * `ALTER TABLE ... ENABLE KEYS' acquired a global lock, preventing
     concurrent execution of other statements that use tables. .  (Bug
     #25044)

   * A return value of `-1' from user-defined handlers was not handled
     well and could result in conflicts with server code.  (Bug #24987)

   * Accessing a fixed record format table with a crashed key
     definition results in server/*Note `myisamchk': myisamchk.
     segmentation fault.  (Bug #24855)

   * *Note `mysqld_multi': mysqld-multi. and *Note `mysqlaccess':
     mysqlaccess. looked for option files in `/etc' even if the
     `--sysconfdir' option for `configure' had been given to specify a
     different directory.  (Bug #24780)

   * If there was insufficient memory available to *Note `mysqld':
     mysqld, this could sometimes cause the server to hang during
     startup.  (Bug #24751)

   * If an `ORDER BY' or `GROUP BY' list included a constant expression
     being optimized away and, at the same time, containing single-row
     subselects that returned more that one row, no error was reported.
     If a query required sorting by expressions containing single-row
     subselects that returned more than one row, execution of the query
     could cause a server crash.  (Bug #24653)

   * For *Note `ALTER TABLE': alter-table, using `ORDER BY EXPRESSION'
     could cause a server crash. Now the `ORDER BY' clause permits only
     column names to be specified as sort criteria (which was the only
     documented syntax, anyway).  (Bug #24562)

   * A workaround was implemented to avoid a race condition in the NPTL
     `pthread_exit()' implementation.  (Bug #24507)

   * `mysqltest' crashed with a stack overflow.  (Bug #24498)

   * Within stored routines or prepared statements, inconsistent
     results occurred with multiple use of `INSERT ... SELECT ... ON
     DUPLICATE KEY UPDATE' when the `ON DUPLICATE KEY UPDATE' clause
     erroneously tried to assign a value to a column mentioned only in
     its *Note `SELECT': select. part.  (Bug #24491)

   * Expressions of the form `(a, b) IN (SELECT a, MIN(b) FROM t GROUP
     BY a)' could produce incorrect results when column `a' of table `t'
     contained `NULL' values while column `b' did not.  (Bug #24420)

   * If a prepared statement accessed a view, access to the tables
     listed in the query after that view was checked in the security
     context of the view.  (Bug #24404)

   * Attempts to access a `MyISAM' table with a corrupt column
     definition caused a server crash.  (Bug #24401)

   * When opening a corrupted `.frm' file during a query, the server
     crashes.  (Bug #24358)

   * A query using `WHERE UNSIGNED_COLUMN NOT IN ('NEGATIVE_VALUE')'
     could cause the server to crash.  (Bug #24261)

   * Expressions of the form `(a, b) IN (SELECT c, d ...)' could
     produce incorrect results if `a', `b', or both were `NULL'.  (Bug
     #24127)

   * A *Note `FETCH': fetch. statement using a cursor on a table which
     was not in the table cache could sometimes cause the server to
     crash.  (Bug #24117)

   * Queries that evaluate `NULL IN (SELECT ... UNION SELECT ...)'
     could produce an incorrect result (`FALSE' instead of `NULL').
     (Bug #24085)

   * Hebrew-to-Unicode conversion failed for some characters.
     Definitions for the following Hebrew characters (as specified by
     the ISO/IEC 8859-8:1999) were added: LEFT-TO-RIGHT MARK (LRM),
     RIGHT-TO-LEFT MARK (RLM) (Bug #24037)

   * Some *Note `UPDATE': update. statements were slower than in
     previous versions when the search key could not be converted to a
     valid value for the type of the search column.  (Bug #24035)

   * `ISNULL(DATE(NULL))' and `ISNULL(CAST(NULL AS DATE))' erroneously
     returned false.  (Bug #23938)

   * Within a stored routine, accessing a declared routine variable
     with `PROCEDURE ANALYSE()' caused a server crash.  (Bug #23782)

   * When reading from the standard input on Windows, *Note
     `mysqlbinlog': mysqlbinlog. opened the input in text mode rather
     than binary mode and consequently misinterpreted some characters
     such as `Control+Z'.  (Bug #23735)

   * For an `InnoDB' table with any `ON DELETE' trigger, *Note
     `TRUNCATE TABLE': truncate-table. mapped to *Note `DELETE': delete.
     and activated triggers. Now a fast truncation occurs and triggers
     are not activated. .  (Bug #23556)

   * The row count for `MyISAM' tables was not updated properly,
     causing *Note `SHOW TABLE STATUS': show-table-status. to report
     incorrect values.  (Bug #23526)

   * With `ONLY_FULL_GROUP_BY' enabled, the server was too strict: Some
     expressions involving only aggregate values were rejected as
     nonaggregate (for example, `MAX(a)' - `MIN(a)').  (Bug #23417)

   * The arguments to the `ENCODE()' and the `DECODE()' functions were
     not printed correctly, causing problems in the output of *Note
     `EXPLAIN EXTENDED': explain. and in view definitions.  (Bug #23409)

   * Some queries against `INFORMATION_SCHEMA' that used subqueries
     failed. .  (Bug #23299)

   * `readline' detection did not work correctly on NetBSD.  (Bug
     #23293)

   * If there was insufficient memory to store or update a blob record
     in a `MyISAM' table then the table will marked as crashed.  (Bug
     #23196)

   * `LAST_INSERT_ID()' was not reset to 0 if *Note `INSERT ...
     SELECT': insert-select. inserted no rows.  (Bug #23170)

   * The number of `setsockopt()' calls performed for reads and writes
     to the network socket was reduced to decrease system call overhead.
     (Bug #22943)

   * *Note `mysql_upgrade': mysql-upgrade. failed when called with a
     `--basedir' path name containing spaces.  (Bug #22801)

   * `SET lc_time_names = VALUE ' permitted only exact literal values,
     not expression values.  (Bug #22647)

   * The `STDDEV()' function returned a positive value for data sets
     consisting of a single value.  (Bug #22555)

   * Storing values specified as hexadecimal values 64 or more bits
     long in `BIT(64)', *Note `BIGINT': numeric-types, or `BIGINT
     UNSIGNED' columns did not raise any warning or error if the value
     was out of range.  (Bug #22533)

   * *Note `SHOW COLUMNS': show-columns. reported some `NOT NULL'
     columns as `NULL'.  (Bug #22377)

   * Type conversion errors during formation of index search conditions
     were not correctly checked, leading to incorrect query results.
     (Bug #22344)

   * The code for generating *Note `USE': use.  statements for binary
     logging of *Note `CREATE PROCEDURE': create-procedure. statements
     resulted in confusing output from *Note `mysqlbinlog':
     mysqlbinlog. for *Note `DROP PROCEDURE': drop-procedure.
     statements.  (Bug #22043)

   * For the `IF()' and `COALESCE()' function and `CASE' expressions,
     large unsigned integer values could be mishandled and result in
     warnings.  (Bug #22026)

   * SSL connections could hang at connection shutdown.  (Bug #21781,
     Bug #24148)

   * When updating a table that used a `JOIN' of the table itself (for
     example, when building trees) and the table was modified on one
     side of the expression, the table would either be reported as
     crashed or the wrong rows in the table would be updated.  (Bug
     #21310)

   * Inserting `DEFAULT' into a column with no default value could
     result in garbage in the column. Now the same result occurs as
     when inserting `NULL' into a `NOT NULL' column.  (Bug #20691)

   * A stored routine containing semicolon in its body could not be
     reloaded from a dump of a binary log.  (Bug #20396)

   * *Note `SELECT ... FOR UPDATE': select, *Note `SELECT ... LOCK IN
     SHARE MODE': select, *Note `DELETE': delete, and *Note `UPDATE':
     update. statements executed using a full table scan were not
     releasing locks on rows that did not satisfy the `WHERE' condition.
     (Bug #20390)

   * On Windows, if the server was installed as a service, it did not
     auto-detect the location of the data directory.  (Bug #20376)

   * The `BUILD/check-cpu' script did not recognize Celeron processors.
     (Bug #20061)

   * If a duplicate key value was present in the table, *Note `INSERT
     ... ON DUPLICATE KEY UPDATE': insert-on-duplicate. reported a row
     count indicating that a record was updated, even when no record
     actually changed due to the old and new values being the same.
     Now it reports a row count of zero.  (Bug #19978) See also Bug
     #27006, Bug #27033, Bug #27210.

   * `ORDER BY' values of the *Note `DOUBLE': numeric-types. or *Note
     `DECIMAL': numeric-types. types could change the result returned
     by a query.  (Bug #19690)

   * The `readline' library wrote to uninitialized memory, causing
     *Note `mysql': mysql. to crash.  (Bug #19474)

   * `mysqltest' incorrectly tried to retrieve result sets for some
     queries where no result set was available.  (Bug #19410)

   * Use of already freed memory caused SSL connections to hang forever.
     (Bug #19209)

   * The server might fail to use an appropriate index for *Note
     `DELETE': delete. when `ORDER BY', `LIMIT', and a nonrestricting
     `WHERE' are present.  (Bug #17711)

   * No warning was issued for use of the `DATA DIRECTORY' or `INDEX
     DIRECTORY' table options on a platform that does not support them.
     (Bug #17498)

   * When a prepared statement failed during the prepare operation, the
     error code was not cleared when it was reused, even if the
     subsequent use was successful.  (Bug #15518)

   * On Windows, the `SLEEP()' function could sleep too long,
     especially after a change to the system clock.  (Bug #14094, Bug
     #24686, Bug #17635)

   * *Note `mysqldump --order-by-primary': mysqldump. failed if the
     primary key name was an identifier that required quoting.  (Bug
     #13926)

   * To enable installation of MySQL RPMs on Linux systems running RHEL
     4 (which includes SE-Linux) additional information was provided to
     specify some actions that are permitted to the MySQL binaries.
     (Bug #12676)

   * The presence of `ORDER BY' in a view definition prevented the
     `MERGE' algorithm from being used to resolve the view even if
     nothing else in the definition required the `TEMPTABLE' algorithm.
     (Bug #12122)


File: manual.info,  Node: news-5-0-34,  Next: news-5-0-33,  Prev: news-5-0-36,  Up: news-5-0-x

D.1.62 Changes in MySQL Enterprise 5.0.34 [MRU] (17 January 2007)
-----------------------------------------------------------------

This is a _Monthly Rapid Update_ release of the MySQL Enterprise Server
5.0.

This section documents all changes and bug fixes that have been applied
since the last MySQL Enterprise Server release (5.0.32).

*Functionality Added or Changed*

   * The `--skip-thread-priority' option now is enabled by default for
     binary Mac OS X distributions. Use of thread priorities degrades
     performance on Mac OS X.  (Bug #18526)

   * Added the `--disable-grant-options' option to `configure'. If
     `configure' is run with this option, the `--bootstrap',
     `--skip-grant-tables', and `--init-file' options for *Note
     `mysqld': mysqld. are disabled and cannot be used. For Windows,
     the `configure.js' script recognizes the `DISABLE_GRANT_OPTIONS'
     flag, which has the same effect.

*Bugs Fixed*

   * *MySQL Cluster*: Hosts in clusters with large numbers of nodes
     could experience excessive CPU usage while obtaining configuration
     data.  (Bug #25711)

   * *MySQL Cluster*: When a data node was shut down using the
     management client `STOP' command, a connection event
     (`NDB_LE_Connected') was logged instead of a disconnection event
     (`NDB_LE_Disconnected').  (Bug #22773)

   * *Cluster API*: Invoking the `NdbTransaction::execute()' method
     using execution type `Commit' and abort option `AO_IgnoreError'
     could lead to a crash of the transaction coordinator (`DBTC').
     (Bug #25090)

   * *Cluster API*: A unique index lookup on a nonexistent tuple could
     lead to a data node timeout (error 4012).  (Bug #25059)

   * Referencing an ambiguous column alias in an expression in the
     `ORDER BY' clause of a query caused the server to crash.  (Bug
     #25427)

   * Using a view in combination with a `USING' clause caused column
     aliases to be ignored.  (Bug #25106)

   * A multiple-table *Note `DELETE QUICK': delete. could sometimes
     cause one of the affected tables to become corrupted.  (Bug #25048)

   * An assertion failed incorrectly for prepared statements that
     contained a single-row uncorrelated subquery that was used as an
     argument of the `IS NULL' predicate.  (Bug #25027)

   * Optimizations that are legal only for subqueries without tables
     and `WHERE' conditions were applied for any subquery without
     tables.  (Bug #24670)

   * Some joins in which one of the joined tables was a view could
     return erroneous results or crash the server.  (Bug #24345)

   * A view was not handled correctly if the *Note `SELECT': select.
     part contained ``\Z''.  (Bug #24293)

   * The server was built even when `configure' was run with the
     `--without-server' option.  (Bug #23973) See also Bug #32898.

   * *Note `OPTIMIZE TABLE': optimize-table. tried to sort R-tree
     indexes such as spatial indexes, although this is not possible
     (see *Note optimize-table::).  (Bug #23578)

   * User-defined variables could consume excess memory, leading to a
     crash caused by the exhaustion of resources available to the
     `MEMORY' storage engine, due to the fact that this engine is used
     by MySQL for variable storage and intermediate results of `GROUP
     BY' queries.  Where *Note `SET': set-option.  had been used, such
     a condition could instead give rise to the misleading error
     message `You may only use constant expressions with SET', rather
     than `Out of memory (Needed NNNNNN bytes)'.  (Bug #23443)

   * A table created with the `ROW_FORMAT = FIXED' table option lost
     that option if an index was added or dropped with *Note `CREATE
     INDEX': create-index. or *Note `DROP INDEX': drop-index.  (Bug
     #23404)

   * A deadlock could occur, with the server hanging on `Closing
     tables', with a sufficient number of concurrent *Note `INSERT
     DELAYED': insert-delayed, *Note `FLUSH TABLES': flush, and *Note
     `ALTER TABLE': alter-table. operations.  (Bug #23312)

   * A compressed `MyISAM' table that became corrupted could crash
     *Note `myisamchk': myisamchk. and possibly the MySQL Server.  (Bug
     #23139)

   * Changing the value of `MI_KEY_BLOCK_LENGTH' in `myisam.h' and
     recompiling MySQL resulted in a *Note `myisamchk': myisamchk. that
     saw existing `MyISAM' tables as corrupt.  (Bug #22119)

   * A crash of the MySQL Server could occur when unpacking a *Note
     `BLOB': blob. column from a row in a corrupted MyISAM table. This
     could happen when trying to repair a table using either *Note
     `REPAIR TABLE': repair-table.  or *Note `myisamchk': myisamchk.;
     it could also happen when trying to access such a `broken' row
     using statements like *Note `SELECT': select. if the table was not
     marked as crashed.  (Bug #22053)

   * The `FEDERATED' storage engine did not support the `euckr'
     character set.  (Bug #21556)

   * `mysqld_error.h' was not installed when only the client libraries
     were built.  (Bug #21265)

   * `InnoDB': During a restart of the MySQL Server that followed the
     creation of a temporary table using the `InnoDB' storage engine,
     MySQL failed to clean up in such a way that `InnoDB' still
     attempted to find the files associated with such tables.  (Bug
     #20867)

   * `InnoDB': Optimizations removed in MySQL 5.0.28 were re-enabled
     except for files under the `innobase/mem' directory. (This is a
     fine-tuning of optimization disabling.)  (Bug #19424)

   * Some *Note `CASE': case-statement.  statements inside stored
     routines could lead to excessive resource usage or a crash of the
     server.  (Bug #19194, Bug #24854)

   * Instance Manager could crash during shutdown.  (Bug #19044)

   * The `FEDERATED' storage engine did not support the `utf8'
     character set.  (Bug #17044)

   * The optimizer removes expressions from `GROUP BY' and `DISTINCT'
     clauses if they happen to participate in ` EXPRESSION = CONSTANT'
     predicates of the `WHERE' clause, the idea being that, if the
     expression is equal to a constant, then it cannot take on multiple
     values. However, for predicates where the expression and the
     constant item are of different result types (for example, when a
     string column is compared to 0), this is not valid, and can lead
     to invalid results in such cases. The optimizer now performs an
     additional check of the result types of the expression and the
     constant; if their types differ, then the expression is not
     removed from the `GROUP BY' list.  (Bug #15881)

   * Dropping a user-defined function sometimes did not remove the UDF
     entry from the `mysql.proc' table.  (Bug #15439)

   * Inserting a row into a table without specifying a value for a
     `BINARY(N) NOT NULL' column caused the column to be set to spaces,
     not zeros.  (Bug #14171)


File: manual.info,  Node: news-5-0-33,  Next: news-5-0-32,  Prev: news-5-0-34,  Up: news-5-0-x

D.1.63 Changes in MySQL Community Server 5.0.33 (09 January 2007)
-----------------------------------------------------------------

This is a bugfix release for the current MySQL Community Server
production release family. It replaces MySQL 5.0.27.

*Note*:

This version of MySQL Community Server has been released as a source
tarball only; there are no binaries built by MySQL.

*Functionality Added or Changed*

   * *Incompatible Change*: `InnoDB' rolls back only the last statement
     on a transaction timeout. A new option,
     `--innodb_rollback_on_timeout', causes `InnoDB' to abort and roll
     back the entire transaction if a transaction timeout occurs (the
     same behavior as in MySQL 5.0.13 and earlier).  (Bug #24200)

   * *Incompatible Change*: The `prepared_stmt_count' system variable
     has been converted to the `Prepared_stmt_count' global status
     variable (viewable with the *Note `SHOW GLOBAL STATUS':
     show-status. statement).  (Bug #23159)

   * *MySQL Cluster*: Setting the configuration parameter
     `LockPagesInMainMemory' had no effect.  (Bug #24461)

   * *MySQL Cluster*: The *Note `ndb_config':
     mysql-cluster-programs-ndb-config. utility now accepts `-c' as a
     short form of the `--ndb-connectstring' option.  (Bug #22295)

   * *MySQL Cluster*: Added the `--bind-address' option for *Note
     `ndbd': mysql-cluster-programs-ndbd. This permits a data node
     process to be bound to a specific network interface.  (Bug #22195)

   * *MySQL Cluster*: It is now possible to create a unique hashed
     index on a column that is not defined as `NOT NULL'.

     *Note*:

     This change applies only to tables using the *Note `NDB':
     mysql-cluster. storage engine.

     Unique indexes on columns in *Note `NDB': mysql-cluster.  tables
     do not store null values because they are mapped to primary keys
     in an internal index table (and primary keys cannot contain nulls).

     Normally, an additional ordered index is created when one creates
     unique indexes on *Note `NDB': mysql-cluster. table columns; this
     can be used to search for `NULL' values. However, if `USING HASH'
     is specified when such an index is created, no ordered index is
     created.

     The reason for permitting unique hash indexes with null values is
     that, in some cases, the user wants to save space if a large
     number of records are pre-allocated but not fully initialized.
     This also assumes that the user will _not_ try to search for null
     values. Since MySQL does not support indexes that are not
     permitted to be searched in some cases, the *Note `NDB':
     mysql-cluster. storage engine uses a full table scan with pushed
     conditions for the referenced index columns to return the correct
     result.

     A warning is returned if one creates a unique nullable hash index,
     since the query optimizer should be provided a hint not to use it
     with `NULL' values if this can be avoided.  (Bug #21507)

   * *MySQL Cluster*: The `Ndb_number_of_storage_nodes' system variable
     was renamed to `Ndb_number_of_data_nodes'.  (Bug #20848)

   * *MySQL Cluster*: The *Note `HELP': help. command in the Cluster
     management client now provides command-specific help. For example,
     `HELP RESTART' in *Note `ndb_mgm': mysql-cluster-programs-ndb-mgm.
     provides detailed information about the `RESTART' command.  (Bug
     #19620)

   * *Note `DROP TRIGGER': drop-trigger. now supports an `IF EXISTS'
     clause.  (Bug #23703)

   * The `Com_create_user' status variable was added (for counting
     *Note `CREATE USER': create-user.  statements).  (Bug #22958)

   * The `--memlock' option relies on system calls that are unreliable
     on some operating systems. If a crash occurs, the server now
     checks whether `--memlock' was specified and if so issues some
     information about possible workarounds.  (Bug #22860)

   * If the user specified the server options `--max-connections=N ' or
     `--table-cache=M ', a warning would be given in some cases that
     some values were recalculated, with the result that
     `--table-cache' could be assigned greater value.

     In such cases, both the warning and the increase in the
     `--table-cache' value were completely harmless. Note also that it
     is not possible for the MySQL Server to predict or to control
     limitations on the maximum number of open files, since this is
     determined by the operating system.

     The value of `--table-cache' is no longer increased automatically,
     and a warning is now given only if some values had to be decreased
     due to operating system limits.  (Bug #21915)

   * For the *Note `CALL': call. statement, stored procedures that take
     no arguments now can be invoked without parentheses. That is,
     `CALL p()' and `CALL p' are equivalent.  (Bug #21462)

   * `mysql_upgrade' now passes all the parameters specified on the
     command line to both `mysqlcheck' and `mysql' using the
     `upgrade_defaults' file.  (Bug #20100)

   * *Note `SHOW STATUS': show-status. is no longer logged to the slow
     query log.  (Bug #19764)

   * *Note `mysqldump --single-transaction': mysqldump. now uses `START
     TRANSACTION /*!40100 WITH CONSISTENT SNAPSHOT */' rather than
     *Note `BEGIN': commit. to start a transaction, so that a
     consistent snapshot will be used on those servers that support it.
     (Bug #19660)

   * The bundled yaSSL library was upgraded to version 1.5.0.

*Bugs Fixed*

   * *Performance*: The `InnoDB' mutex structure was simplified to
     reduce memory load.  (Bug #24386)

   * *Performance*: `InnoDB' exhibited thread thrashing with more than
     50 concurrent connections under an update-intensive workload.
     (Bug #22868)

   * *Performance*: Evaluation of subqueries that require the filesort
     algorithm were allocating and freeing the `sort_buffer_size'
     buffer many times, resulting in slow performance. Now the buffer is
     allocated once and reused.  (Bug #21727)

   * *Performance*: `InnoDB' showed substandard performance with
     multiple queries running concurrently.  (Bug #15815)

   * *MySQL Cluster*: The failure of a data node failure during a
     schema operation could lead to additional node failures.  (Bug
     #24752)

   * *MySQL Cluster*: A committed read could be attempted before a data
     node had time to connect, causing a timeout error.  (Bug #24717)

   * *MySQL Cluster*: Sudden disconnection of an SQL or data node could
     lead to shutdown of data nodes with the error `failed ndbrequire'.
     (Bug #24447)

   * *MySQL Cluster*: *Note `ndb_config':
     mysql-cluster-programs-ndb-config. failed when trying to use 2
     management servers and node IDs.  (Bug #23887)

   * *MySQL Cluster*: Backup of a cluster failed if there were any
     tables with 128 or more columns.  (Bug #23502)

   * *MySQL Cluster*: Cluster backups failed when there were more than
     2048 schema objects in the cluster.  (Bug #23499)

   * *MySQL Cluster*: The management client command `ALL DUMP 1000'
     would cause the cluster to crash if data nodes were connected to
     the cluster but not yet fully started.  (Bug #23203)

   * *MySQL Cluster*: *Note `INSERT ... ON DUPLICATE KEY UPDATE':
     insert-on-duplicate. on an *Note `NDB': mysql-cluster. table could
     lead to deadlocks and memory leaks.  (Bug #23200)

   * *MySQL Cluster*: (NDB API): Inacivity timeouts for scans were not
     correctly handled.  (Bug #23107)

   * *MySQL Cluster*: If a node restart could not be performed from the
     REDO log, no node takeover took place. This could cause partitions
     to be left empty during a system restart.  (Bug #22893)

   * *MySQL Cluster*: Multiple node restarts in rapid succession could
     cause a system restart to fail , or induce a race condition.  (Bug
     #22892, Bug #23210)

   * *MySQL Cluster*: (NDB API): Attempting to read a nonexistent tuple
     using `Commit' mode for `NdbTransaction::execute()' caused node
     failures.  (Bug #22672)

   * *MySQL Cluster*: The `--help' output from *Note `NDB':
     mysql-cluster. binaries did not include file-related options.
     (Bug #21994)

   * *MySQL Cluster*: (NDB API): Scans closed before being executed
     were still placed in the send queue.  (Bug #21941)

   * *MySQL Cluster*: A scan timeout returned Error 4028 (`Node failure
     caused abort of transaction') instead of Error 4008 (`Node failure
     caused abort of transaction...').  (Bug #21799)

   * *MySQL Cluster*: The node recovery algorithm was missing a version
     check for tables in the `ALTER_TABLE_COMMITTED' state (as opposed
     to the `TABLE_ADD_COMMITTED' state, which has the version check).
     This could cause inconsistent schemas across nodes following node
     recovery.  (Bug #21756)

   * *MySQL Cluster*: The output for the `--help' option used with
     *Note `NDB': mysql-cluster. executable programs (such as *Note
     `ndbd': mysql-cluster-programs-ndbd, *Note `ndb_mgm':
     mysql-cluster-programs-ndb-mgm, *Note `ndb_restore':
     mysql-cluster-programs-ndb-restore, *Note `ndb_config':
     mysql-cluster-programs-ndb-config, and others mentioned in *Note
     mysql-cluster-programs::) referred to the `Ndb.cfg' file, instead
     of to `my.cnf'.  (Bug #21585)

   * *MySQL Cluster*: Partition distribution keys were updated only for
     the primary and starting replicas during node recovery. This could
     lead to node failure recovery for clusters having an odd number of
     replicas.

     *Note*:

     For best results, use values for `NumberOfReplicas' that are even
     powers of 2.

     (Bug #21535)

   * *MySQL Cluster*: The *Note `ndb_mgm':
     mysql-cluster-programs-ndb-mgm. management client did not set the
     exit status on errors, always returning 0 instead.  (Bug #21530)

   * *MySQL Cluster*: Cluster logs were not rotated following the first
     rotation cycle.  (Bug #21345)

   * *MySQL Cluster*: When inserting a row into an *Note `NDB':
     mysql-cluster.  table with a duplicate value for a nonprimary
     unique key, the error issued would reference the wrong key.  (Bug
     #21072)

   * *MySQL Cluster*: Condition pushdown did not work correctly with
     *Note `DATETIME': datetime. columns.  (Bug #21056)

   * *MySQL Cluster*: Under some circumstances, local checkpointing
     would hang, keeping any unstarted nodes from being started.  (Bug
     #20895)

   * *MySQL Cluster*: Using an invalid node ID with the management
     client `STOP' command could cause *Note `ndb_mgm':
     mysql-cluster-programs-ndb-mgm. to hang.  (Bug #20575)

   * *MySQL Cluster*: Data nodes added while the cluster was running in
     single user mode were all assigned node ID 0, which could later
     cause multiple node failures. Adding nodes while in single user
     mode is no longer possible.  (Bug #20395)

   * *MySQL Cluster*: In some cases where `SELECT COUNT(*)' from an
     *Note `NDB': mysql-cluster. table should have yielded an error,
     `MAX_INT' was returned instead.  (Bug #19914)

   * *MySQL Cluster*: Following the restart of a management node, the
     Cluster management client did not automatically reconnect.  (Bug
     #19873)

   * *MySQL Cluster*: Error messages given when trying to make online
     changes to parameters such as `NoOfReplicas' that can only be
     changed using a complete shutdown and restart of the cluster did
     not indicate the true nature of the problem.  (Bug #19787)

   * *MySQL Cluster*: *Note `ndb_restore':
     mysql-cluster-programs-ndb-restore. did not always make clear that
     it had recovered successfully from temporary errors while restoring
     a cluster backup.  (Bug #19651)

   * *MySQL Cluster*: In rare situations with resource shortages, a
     crash could result from an insufficient number of
     `IndexScanOperation' objects.  (Bug #19198)

   * *MySQL Cluster*: *Note `ndb_mgm -e show | head':
     mysql-cluster-programs-ndb-mgm. would hang after displaying the
     first 10 lines of output.  (Bug #19047)

   * *MySQL Cluster*: The error returned by the cluster when too many
     nodes were defined did not make clear the nature of the problem.
     (Bug #19045)

   * *MySQL Cluster*: A unique constraint violation was not ignored by
     an `UPDATE IGNORE' statement when the constraint violation
     occurred on a nonprimary key.  (Bug #18487, Bug #24303)

   * *MySQL Cluster*: The *Note `ndb_config':
     mysql-cluster-programs-ndb-config. utility did not perform host
     lookups correctly when using the `--host' option (Bug #17582)

   * *MySQL Cluster*: A problem with takeover during a system restart
     caused ordered indexes to be rebuilt incorrectly.  (Bug #15303)

   * *Replication*: Changes to character set variables prior to an
     action on a replication-ignored table were forgotten by slave
     servers.  (Bug #22877)

   * *Replication*: On slave servers, transactions that exceeded the
     lock wait timeout failed to roll back properly.  (Bug #20697)

   * *Replication*: Column names were not quoted properly for
     replicated views.  (Bug #19736)

   * *Replication*: SQL statements close to the size of
     `max_allowed_packet' could produce binary log events larger than
     `max_allowed_packet' that could not be read by slave servers.
     (Bug #19402)

   * *Replication*: Slave servers would retry the execution of an SQL
     statement an infinite number of times, ignoring the value
     `SLAVE_TRANSACTION_RETRIES' when using the NDB engine.  (Bug
     #16228)

   * *Replication*: Transient errors in replication from master to
     slave may trigger multiple `Got fatal error 1236: 'binlog
     truncated in the middle of event'' errors on the slave.  (Bug
     #4053)

   * *Cluster API*: Using *Note `BIT': numeric-types. values with any
     of the comparison methods of the `NdbScanFilter' class caused data
     nodes to fail.  (Bug #24503)

   * *Cluster API*: Some MGM API function calls could yield incorrect
     return values in certain cases where the cluster was operating
     under a very high load, or experienced timeouts in inter-node
     communications.  (Bug #24011)

   * *Cluster API*: The `NdbOperation::getBlobHandle()' method, when
     called with the name of a nonexistent column, caused a
     segmentation fault.  (Bug #21036)

   * *Cluster API*: When multiple processes or threads in parallel
     performed the same ordered scan with exclusive lock and updated
     the retrieved records, the scan could skip some records, which as
     a result were not updated.  (Bug #20446)

   * The `REPEAT()' function could return `NULL' when passed a column
     for the count argument.  (Bug #24947)

   * *Note `mysql_upgrade': mysql-upgrade. failed if the `--password'
     (or `-p') option was given.  (Bug #24896)

   * With `innodb_file_per_table' enabled, `InnoDB' displayed incorrect
     file times in the output from *Note `SHOW TABLE STATUS':
     show-table-status.  (Bug #24712)

   * *Note `ALTER TABLE ENABLE KEYS': alter-table. or *Note `ALTER
     TABLE DISABLE KEYS': alter-table. combined with another *Note
     `ALTER TABLE': alter-table. option other than `RENAME TO' did
     nothing. In addition, if *Note `ALTER TABLE': alter-table. was
     used on a table having disabled keys, the keys of the resulting
     table were enabled.  (Bug #24395)

   * The `--extern' option for `mysql-test-run.pl' did not function
     correctly.  (Bug #24354)

   * Foreign key identifiers for `InnoDB' tables could not contain
     certain characters.  (Bug #24299)

   * The *Note `mysql.server': mysql-server. script used the `source'
     command, which is less portable than the `.' command; it now uses
     `.' instead.  (Bug #24294)

   * *Note `ALTER TABLE': alter-table. statements that performed both
     `RENAME TO' and `{ENABLE|DISABLE} KEYS' operations caused a server
     crash.  (Bug #24219)

   * The loose index scan optimization for `GROUP BY' with `MIN' or
     `MAX' was not applied within other queries, such as *Note `CREATE
     TABLE ... SELECT ...': create-table, `INSERT ... SELECT ...', or
     in the `FROM' clauses of subqueries.  (Bug #24156)

   * There was a race condition in the `InnoDB'
     `fil_flush_file_spaces()' function.  (Bug #24089) This regression
     was introduced by Bug #15653.

   * Subqueries for which a pushed-down condition did not produce
     exactly one key field could cause a server crash.  (Bug #24056)

   * The size of `MEMORY' tables and internal temporary tables was
     limited to 4GB on 64-bit Windows systems.  (Bug #24052)

   * yaSSL-related memory leaks were detected by Valgrind.  (Bug #23981)

   * The internal SQL interpreter of `InnoDB' placed an unnecessary
     lock on the supremum record with `innodb_locks_unsafe_for_binlog'
     enabled. This caused an assertion failure when `InnoDB' was built
     with debugging enabled.  (Bug #23769)

   * `ROW_COUNT()' did not work properly as an argument to a stored
     procedure.  (Bug #23760)

   * `LAST_DAY('0000-00-00')' could cause a server crash.  (Bug #23653)

   * A trigger that invoked a stored function could cause a server
     crash when activated by different client connections.  (Bug #23651)

   * The stack size for NetWare binaries was increased to 128KB to
     prevent problems caused by insufficient stack size.  (Bug #23504)

   * If elements in a nontop-level `IN' subquery were accessed by an
     index and the subquery result set included a `NULL' value, the
     quantified predicate that contained the subquery was evaluated to
     `NULL' when it should return a non-`NULL' value.  (Bug #23478)

   * When applying the `group_concat_max_len' limit, `GROUP_CONCAT()'
     could truncate multi-byte characters in the middle.  (Bug #23451)

   * MySQL 5.0.26 introduced an ABI incompatibility, which this release
     reverts. Programs compiled against 5.0.26 are not compatible with
     any other version and must be recompiled.  (Bug #23427)

   * `M % 0' returns `NULL', but (` M % 0) IS NULL' evaluated to false.
     (Bug #23411)

   * *Note `mysql_affected_rows()': mysql-affected-rows. could return
     values different from *Note `mysql_stmt_affected_rows()':
     mysql-stmt-affected-rows. for the same sequence of statements.
     (Bug #23383)

   * For not-yet-authenticated connections, the `Time' column in *Note
     `SHOW PROCESSLIST': show-processlist. was a random value rather
     than `NULL'.  (Bug #23379)

   * Accuracy was improved for comparisons between *Note `DECIMAL':
     numeric-types. columns and numbers represented as strings.  (Bug
     #23260)

   * MySQL failed to build on Linux/Alpha.  (Bug #23256) This
     regression was introduced by Bug #21250.

   * If `COMPRESS()' returned `NULL', subsequent invocations of
     `COMPRESS()' within a result set or within a trigger also returned
     `NULL'.  (Bug #23254)

   * Calculation of `COUNT(DISTINCT)', `AVG(DISTINCT)', or
     `SUM(DISTINCT)' when they are referenced more than once in a
     single query with `GROUP BY' could cause a server crash.  (Bug
     #23184)

   * Insufficient memory (`myisam_sort_buffer_size') could cause a
     server crash for several operations on `MyISAM' tables: repair
     table, create index by sort, repair by sort, parallel repair, bulk
     insert.  (Bug #23175)

   * The column default value in the output from *Note `SHOW COLUMNS':
     show-columns. or `SELECT FROM INFORMATION_SCHEMA.COLUMNS' was
     truncated to 64 characters.  (Bug #23037)

   * *Note `mysql': mysql. did not check for errors when fetching data
     during result set printing.  (Bug #22913)

   * The return value from `my_seek()' was ignored.  (Bug #22828)

   * The optimizer failed to use equality propagation for `BETWEEN' and
     `IN' predicates with string arguments.  (Bug #22753)

   * The `Handler_rollback' status variable sometimes was incremented
     when no rollback had taken place.  (Bug #22728)

   * The `Host' column in *Note `SHOW PROCESSLIST': show-processlist.
     output was blank when the server was started with the
     `--skip-grant-tables' option.  (Bug #22723)

   * If a table contains an `AUTO_INCREMENT' column, inserting into an
     insertable view on the table that does not include the
     `AUTO_INCREMENT' column should not change the value of
     `LAST_INSERT_ID()', because the side effects of inserting default
     values into columns not part of the view should not be visible.
     MySQL was incorrectly setting `LAST_INSERT_ID()' to zero.  (Bug
     #22584)

   * Queries using a column alias in an expression as part of an `ORDER
     BY' clause failed, an example of such a query being `SELECT mycol
     + 1 AS mynum FROM mytable ORDER BY 30 - mynum'.  (Bug #22457)

   * Using *Note `EXPLAIN': explain. caused a server crash for queries
     that selected from `INFORMATION_SCHEMA' in a subquery in the
     `FROM' clause.  (Bug #22413)

   * Instance Manager had a race condition involving ` mysqld' PID file
     removal.  (Bug #22379)

   * A server crash occurred when using *Note `LOAD DATA': load-data.
     to load a table containing a `NOT NULL' spatial column, when the
     statement did not load the spatial column. Now a `NULL supplied to
     NOT NULL column' error occurs.  (Bug #22372)

   * The optimizer used the `ref' join type rather than `eq_ref' for a
     simple join on strings.  (Bug #22367)

   * Some queries that used `MAX()' and `GROUP BY' could incorrectly
     return an empty result.  (Bug #22342)

   * `DATE_ADD()' requires complete dates with no `zero' parts, but
     sometimes did not return `NULL' when given such a date.  (Bug
     #22229)

   * If an `init_connect' SQL statement produced an error, the
     connection was silently terminated with no error message. Now the
     server writes a warning to the error log.  (Bug #22158)

   * Some small double precision numbers (such as `1.00000001e-300')
     that should have been accepted were truncated to zero.  (Bug
     #22129)

   * For a nonexistent table, `DROP TEMPORARY TABLE' failed with an
     incorrect error message if `read_only' was enabled.  (Bug #22077)

   * Trailing spaces were not removed from Unicode *Note `CHAR': char.
     column values when used in indexes. This resulted in excessive
     usage of storage space, and could affect the results of some
     `ORDER BY' queries that made use of such indexes.

     *Note*:

     When upgrading, it is necessary to re-create any existing indexes
     on Unicode *Note `CHAR': char. columns of each affected table to
     take advantage of the fix. See *Note rebuilding-tables::.

     (Bug #22052)

   * The code for generating *Note `USE': use.  statements for binary
     logging of *Note `CREATE PROCEDURE': create-procedure. statements
     resulted in confusing output from *Note `mysqlbinlog':
     mysqlbinlog. for *Note `DROP PROCEDURE': drop-procedure.
     statements.  (Bug #22043)

   * `STR_TO_DATE()' returned `NULL' if the format string contained a
     space following a nonformat character.  (Bug #22029)

   * Use of a DES-encrypted SSL certificate file caused a server crash.
     (Bug #21868)

   * Use of *Note `PREPARE': prepare. with a *Note `CREATE PROCEDURE':
     create-procedure. statement that contained a syntax error caused a
     server crash.  (Bug #21856)

   * Adding a day, month, or year interval to a *Note `DATE': datetime.
     value produced a *Note `DATE': datetime, but adding a week interval
     produced a *Note `DATETIME': datetime. value. Now all produce a
     *Note `DATE': datetime. value.  (Bug #21811)

   * In some cases, the parser failed to distinguish a user-defined
     function from a stored function.  (Bug #21809)

   * Use of a subquery that invoked a function in the column list of
     the outer query resulted in a memory leak.  (Bug #21798)

   * Inserting a default or invalid value into a spatial column could
     fail with `Unknown error' rather than a more appropriate error.
     (Bug #21790)

   * It was possible to use *Note `DATETIME': datetime.  values whose
     year, month, and day parts were all zeros but whose hour, minute,
     and second parts contained nonzero values, an example of such an
     illegal *Note `DATETIME': datetime. being `'0000-00-00 11:23:45''.

     *Note*:

     This fix was reverted in MySQL 5.0.40.

     (Bug #21789) See also Bug #25301.

   * yaSSL crashed on pre-Pentium Intel CPUs.  (Bug #21765)

   * Through the C API, the member strings in `MYSQL_FIELD' for a query
     that contained expressions could return incorrect results.  (Bug
     #21635)

   * Selecting from a `MERGE' table could result in a server crash if
     the underlying tables had fewer indexes than the `MERGE' table
     itself.  (Bug #21617, Bug #22937)

   * View columns were always handled as having implicit derivation,
     leading to `illegal mix of collation errors' for some views in
     *Note `UNION': union.  operations. Now view column derivation
     comes from the original expression given in the view definition.
     (Bug #21505)

   * `InnoDB' crashed while performing XA recovery of prepared
     transactions.  (Bug #21468)

   * `INET_ATON()' returned a signed *Note `BIGINT': numeric-types.
     value, not an unsigned value.  (Bug #21466)

   * After *Note `FLUSH TABLES WITH READ LOCK': flush. followed by
     *Note `UNLOCK TABLES': lock-tables, attempts to drop or alter a
     stored routine failed with an error that the routine did not
     exist, and attempts to execute the routine failed with a lock
     conflict error.  (Bug #21414)

   * It was possible to set the backslash character (``\'') as the
     delimiter character using `DELIMITER', but not actually possible to
     use it as the delimiter.  (Bug #21412)

   * For multiple-table *Note `UPDATE': update.  statements, storage
     engines were not notified of duplicate-key errors.  (Bug #21381)

   * Within a prepared statement, `SELECT (COUNT(*) = 1)' (or similar
     use of other aggregate functions) did not return the correct
     result for statement re-execution.  (Bug #21354)

   * It was possible for a stored routine with a non-`latin1' name to
     cause a stack overrun.  (Bug #21311)

   * Certain malformed *Note `INSERT': insert.  statements could crash
     the *Note `mysql': mysql. client.  (Bug #21142)

   * Creating a `TEMPORARY' table with the same name as an existing
     table that was locked by another client could result in a lock
     conflict for `DROP TEMPORARY TABLE' because the server
     unnecessarily tried to acquire a name lock.  (Bug #21096)

   * Incorrect results could be obtained from re-execution of a
     parametrized prepared statement or a stored routine with a *Note
     `SELECT': select. that uses `LEFT JOIN' with a second table having
     only one row.  (Bug #21081)

   * Within a stored routine, a view definition cannot refer to routine
     parameters or local variables. However, an error did not occur
     until the routine was called. Now it occurs during parsing of the
     routine creation statement.

     *Note*:

     A side effect of this fix is that if you have already created such
     routines, and error will occur if you execute *Note `SHOW CREATE
     PROCEDURE': show-create-procedure. or *Note `SHOW CREATE
     FUNCTION': show-create-function. You should drop these routines
     because they are erroneous.

     (Bug #20953)

   * In *Note `mysql': mysql, invoking `connect' or `\r' with very long
     DB_NAME or HOST_NAME parameters caused buffer overflow.  (Bug
     #20894)

   * *Note `SHOW VARIABLES': show-variables. truncated the `Value'
     field to 256 characters.  (Bug #20862)

   * Selecting into variables sometimes returned incorrect wrong
     results.  (Bug #20836)

   * `WITH ROLLUP' could group unequal values.  (Bug #20825)

   * Range searches on columns with an index prefix could miss records.
     (Bug #20732)

   * Inserting `DEFAULT' into a column with no default value could
     result in garbage in the column. Now the same result occurs as
     when inserting `NULL' into a `NOT NULL' column.  (Bug #20691)

   * An *Note `UPDATE': update. that referred to a key column in the
     `WHERE' clause and activated a trigger that modified the column
     resulted in a loop.  (Bug #20670)

   * `CONCURRENT' did not work correctly for *Note `LOAD DATA INFILE':
     load-data.  (Bug #20637)

   * `mysql_fix_privilege_tables.sql' altered the
     `table_privs.table_priv' column to contain too few privileges,
     causing loss of the *Note `CREATE VIEW': create-view. and `SHOW
     VIEW' privileges.  (Bug #20589)

   * `LIKE' searches failed for indexed `utf8' character columns.  (Bug
     #20471)

   * With `lower_case_table_names' set to 1, *Note `SHOW CREATE TABLE':
     show-create-table. printed incorrect output for table names
     containing Turkish I (LATIN CAPITAL LETTER I WITH DOT ABOVE).
     (Bug #20404)

   * A query with a subquery that references columns of a view from the
     outer *Note `SELECT': select. could return an incorrect result if
     used from a prepared statement.  (Bug #20327)

   * For queries that select from a view, the server returned
     `MYSQL_FIELD' metadata inconsistently for view names and table
     names. For view columns, the server now returns the view name in
     the `table' field and, if the column selects from an underlying
     table, the table name in the `org_table' field.  (Bug #20191)

   * Invalidating the query cache caused a server crash for *Note
     `INSERT INTO ... SELECT': insert-select. statements that selected
     from a view.  (Bug #20045)

   * With `sql_mode = TRADITIONAL', MySQL incorrectly aborted on
     warnings within stored routines and triggers.  (Bug #20028)

   * Unsigned *Note `BIGINT': numeric-types. values treated as signed
     values by the `MOD()' function.  (Bug #19955)

   * Compiling PHP 5.1 with the MySQL static libraries failed on some
     versions of Linux.  (Bug #19817)

   * The `DELIMITER' statement did not work correctly when used in an
     SQL file run using the `SOURCE' statement.  (Bug #19799)

   * *Note `mysqldump --xml': mysqldump. produced invalid XML for *Note
     `BLOB': blob. data.  (Bug #19745)

   * For a cast of a *Note `DATETIME': datetime. value containing
     microseconds to *Note `DECIMAL': numeric-types, the microseconds
     part was truncated without generating a warning. Now the
     microseconds part is preserved.  (Bug #19491)

   * `InnoDB': Reduced optimization level for Windows 64 builds to
     handle possible memory overrun.  (Bug #19424)

   * *Note `VARBINARY': binary-varbinary. column values inserted on a
     MySQL 4.1 server had trailing zeros following upgrade to MySQL 5.0
     or later.  (Bug #19371)

   * `FLUSH INSTANCES' in Instance Manager triggered an assertion
     failure.  (Bug #19368)

   * For a debug server, a reference to an undefined user variable in a
     prepared statement executed with *Note `EXECUTE': execute. caused
     an assertion failure.  (Bug #19356)

   * The server could send incorrect column count information to the
     client for queries that produce a larger number of columns than
     can fit in a two-byte number.  (Bug #19216)

   * Within a trigger for a base table, selecting from a view on that
     base table failed.  (Bug #19111)

   * The value of the `warning_count' system variable was not being
     calculated correctly (also affecting *Note `SHOW COUNT(*)
     WARNINGS': show-warnings.).  (Bug #19024)

   * For some problems relating to character set conversion or
     incorrect string values for *Note `INSERT': insert. or *Note
     `UPDATE': update, the server reported truncation or length errors
     instead.  (Bug #18908)

   * `DELETE IGNORE' could hang for foreign key parent deletes.  (Bug
     #18819)

   * Constant expressions and some numeric constants used as input
     parameters to user-defined functions were not treated as constants.
     (Bug #18761)

   * `InnoDB' used table locks (not row locks) within stored functions.
     (Bug #18077)

   * *Note `myisampack': myisampack. wrote to unallocated memory,
     causing a crash.  (Bug #17951)

   * *Note `FLUSH LOGS': flush. or *Note `mysqladmin flush-logs':
     mysqladmin. caused a server crash if the binary log was not open.
     (Bug #17733)

   * *Note `mysql_fix_privilege_tables': mysql-fix-privilege-tables.
     did not accept a password containing embedded space or apostrophe
     characters.  (Bug #17700)

   * *Note `mysql': mysql. would lose its connection to the server if
     its standard output was not writable.  (Bug #17583)

   * Attempting to use a view containing `DEFINER' information for a
     nonexistent user resulted in an error message that revealed the
     definer account. Now the definer is revealed only to users that
     have the `SUPER' privilege. Other users receive only an `access
     denied' message.  (Bug #17254)

   * `mysql-test-run' did not work correctly for RPM-based
     installations.  (Bug #17194)

   * `IN()' and `CHAR()' can return `NULL', but did not signal that to
     the query processor, causing incorrect results for `IS NULL'
     operations.  (Bug #17047)

   * A client library crash was caused by executing a statement such as
     `SELECT * FROM t1 PROCEDURE ANALYSE()' using a server side cursor
     on a table `t1' that does not have the same number of columns as
     the output from `PROCEDURE ANALYSE()'.  (Bug #17039)

   * The `WITH CHECK OPTION' for a view failed to prevent storing
     invalid column values for *Note `UPDATE': update. statements.
     (Bug #16813)

   * *Note `ALTER TABLE': alter-table. was not able to rename a view.
     (Bug #14959)

   * Statements such as *Note `DROP PROCEDURE': drop-procedure.  and
     *Note `DROP VIEW': drop-view. were written to the binary log too
     late due to a race condition.  (Bug #14262)

   * A literal string in a `GROUP BY' clause could be interpreted as a
     column name.  (Bug #14019)

   * Instance Manager didn't close the client socket file when starting
     a new *Note `mysqld': mysqld. instance.  *Note `mysqld': mysqld.
     inherited the socket, causing clients connected to Instance
     Manager to hang.  (Bug #12751)

   * Entries in the slow query log could have an incorrect
     `Rows_examined' value.  (Bug #12240)

   * Warnings were generated when explicitly casting a character to a
     number (for example, `CAST('x' AS SIGNED)'), but not for implicit
     conversions in simple arithmetic operations (such as `'x' + 0').
     Now warnings are generated in all cases.  (Bug #11927)

   * Lack of validation for input and output *Note `TIME': time. values
     resulted in several problems: `SEC_TO_TIME()' in some cases did
     not clip large values to the *Note `TIME': time. range
     appropriately; `SEC_TO_TIME()' treated `BIGINT UNSIGNED' values as
     signed; only truncation warnings were produced when both
     truncation and out-of-range *Note `TIME': time. values occurred.
     (Bug #11655, Bug #20927)

   * Metadata for columns calculated from scalar subqueries was limited
     to integer, double, or string, even if the actual type of the
     column was different.  (Bug #11032)

   * Several string functions could return incorrect results when given
     very large length arguments.  (Bug #10963)

   * `FROM_UNIXTIME()' did not accept arguments up to `POWER(2,31)-1',
     which it had previously.  (Bug #9191)

   * Subqueries of the form `NULL IN (SELECT ...)' returned invalid
     results.  (Bug #8804, Bug #23485)

   * *Note `OPTIMIZE TABLE': optimize-table. with
     `myisam_repair_threads' > 1 could result in `MyISAM' table
     corruption.  (Bug #8283)


File: manual.info,  Node: news-5-0-32,  Next: news-5-0-30sp1,  Prev: news-5-0-33,  Up: news-5-0-x

D.1.64 Changes in MySQL Enterprise 5.0.32 [MRU] (20 December 2006)
------------------------------------------------------------------

This is a _Monthly Rapid Update_ release of the MySQL Enterprise Server
5.0.

This section documents all changes and bug fixes that have been applied
since the last MySQL Enterprise Server release (5.0.30).

*Functionality Added or Changed*

   * *Incompatible Change*: `InnoDB' rolls back only the last statement
     on a transaction timeout. A new option,
     `--innodb_rollback_on_timeout', causes `InnoDB' to abort and roll
     back the entire transaction if a transaction timeout occurs (the
     same behavior as in MySQL 5.0.13 and earlier).  (Bug #24200)

   * *Incompatible Change*: The `prepared_stmt_count' system variable
     has been converted to the `Prepared_stmt_count' global status
     variable (viewable with the *Note `SHOW GLOBAL STATUS':
     show-status. statement).  (Bug #23159)

   * *MySQL Cluster*: Setting the configuration parameter
     `LockPagesInMainMemory' had no effect.  (Bug #24461)

   * *MySQL Cluster*: It is now possible to create a unique hashed
     index on a column that is not defined as `NOT NULL'.

     *Note*:

     This change applies only to tables using the *Note `NDB':
     mysql-cluster. storage engine.

     Unique indexes on columns in *Note `NDB': mysql-cluster.  tables
     do not store null values because they are mapped to primary keys
     in an internal index table (and primary keys cannot contain nulls).

     Normally, an additional ordered index is created when one creates
     unique indexes on *Note `NDB': mysql-cluster. table columns; this
     can be used to search for `NULL' values. However, if `USING HASH'
     is specified when such an index is created, no ordered index is
     created.

     The reason for permitting unique hash indexes with null values is
     that, in some cases, the user wants to save space if a large
     number of records are pre-allocated but not fully initialized.
     This also assumes that the user will _not_ try to search for null
     values. Since MySQL does not support indexes that are not
     permitted to be searched in some cases, the *Note `NDB':
     mysql-cluster. storage engine uses a full table scan with pushed
     conditions for the referenced index columns to return the correct
     result.

     A warning is returned if one creates a unique nullable hash index,
     since the query optimizer should be provided a hint not to use it
     with `NULL' values if this can be avoided.  (Bug #21507)

   * *Note `DROP TRIGGER': drop-trigger. now supports an `IF EXISTS'
     clause.  (Bug #23703)

   * The `Com_create_user' status variable was added (for counting
     *Note `CREATE USER': create-user.  statements).  (Bug #22958)

   * The `--memlock' option relies on system calls that are unreliable
     on some operating systems. If a crash occurs, the server now
     checks whether `--memlock' was specified and if so issues some
     information about possible workarounds.  (Bug #22860)

   * *Note `mysqldump': mysqldump. now accepts the `--debug-info'
     option, which displays debugging information and memory and CPU
     usage statistics at program exit.

   * The bundled yaSSL library was upgraded to version 1.5.0.

*Bugs Fixed*

   * *Performance*: The `InnoDB' mutex structure was simplified to
     reduce memory load.  (Bug #24386)

   * *Performance*: Evaluation of subqueries that require the filesort
     algorithm were allocating and freeing the `sort_buffer_size'
     buffer many times, resulting in slow performance. Now the buffer is
     allocated once and reused.  (Bug #21727)

   * *MySQL Cluster*: The failure of a data node failure during a
     schema operation could lead to additional node failures.  (Bug
     #24752)

   * *MySQL Cluster*: A committed read could be attempted before a data
     node had time to connect, causing a timeout error.  (Bug #24717)

   * *MySQL Cluster*: Sudden disconnection of an SQL or data node could
     lead to shutdown of data nodes with the error `failed ndbrequire'.
     (Bug #24447)

   * *MySQL Cluster*: *Note `ndb_config':
     mysql-cluster-programs-ndb-config. failed when trying to use 2
     management servers and node IDs.  (Bug #23887)

   * *MySQL Cluster*: If the value set for `MaxNoOfAttributes' is
     excessive, a suitable error message is now returned.  (Bug #19352)

   * *MySQL Cluster*: A unique constraint violation was not ignored by
     an `UPDATE IGNORE' statement when the constraint violation
     occurred on a nonprimary key.  (Bug #18487, Bug #24303)

   * *Replication*: Changes to character set variables prior to an
     action on a replication-ignored table were forgotten by slave
     servers.  (Bug #22877)

   * *Replication*: On slave servers, transactions that exceeded the
     lock wait timeout failed to roll back properly.  (Bug #20697)

   * *Replication*: SQL statements close to the size of
     `max_allowed_packet' could produce binary log events larger than
     `max_allowed_packet' that could not be read by slave servers.
     (Bug #19402)

   * *Replication*: Slave servers would retry the execution of an SQL
     statement an infinite number of times, ignoring the value
     `SLAVE_TRANSACTION_RETRIES' when using the NDB engine.  (Bug
     #16228)

   * *Cluster API*: Using *Note `BIT': numeric-types. values with any
     of the comparison methods of the `NdbScanFilter' class caused data
     nodes to fail.  (Bug #24503)

   * *Cluster API*: Some MGM API function calls could yield incorrect
     return values in certain cases where the cluster was operating
     under a very high load, or experienced timeouts in inter-node
     communications.  (Bug #24011)

   * The `REPEAT()' function could return `NULL' when passed a column
     for the count argument.  (Bug #24947)

   * *Note `mysql_upgrade': mysql-upgrade. failed if the `--password'
     (or `-p') option was given.  (Bug #24896)

   * With `innodb_file_per_table' enabled, `InnoDB' displayed incorrect
     file times in the output from *Note `SHOW TABLE STATUS':
     show-table-status.  (Bug #24712)

   * *Note `ALTER TABLE ENABLE KEYS': alter-table. or *Note `ALTER
     TABLE DISABLE KEYS': alter-table. combined with another *Note
     `ALTER TABLE': alter-table. option other than `RENAME TO' did
     nothing. In addition, if *Note `ALTER TABLE': alter-table. was
     used on a table having disabled keys, the keys of the resulting
     table were enabled.  (Bug #24395)

   * The `--extern' option for `mysql-test-run.pl' did not function
     correctly.  (Bug #24354)

   * Foreign key identifiers for `InnoDB' tables could not contain
     certain characters.  (Bug #24299)

   * The *Note `mysql.server': mysql-server. script used the `source'
     command, which is less portable than the `.' command; it now uses
     `.' instead.  (Bug #24294)

   * *Note `ALTER TABLE': alter-table. statements that performed both
     `RENAME TO' and `{ENABLE|DISABLE} KEYS' operations caused a server
     crash.  (Bug #24219)

   * The loose index scan optimization for `GROUP BY' with `MIN' or
     `MAX' was not applied within other queries, such as *Note `CREATE
     TABLE ... SELECT ...': create-table, `INSERT ... SELECT ...', or
     in the `FROM' clauses of subqueries.  (Bug #24156)

   * Subqueries for which a pushed-down condition did not produce
     exactly one key field could cause a server crash.  (Bug #24056)

   * The size of `MEMORY' tables and internal temporary tables was
     limited to 4GB on 64-bit Windows systems.  (Bug #24052)

   * `ROW_COUNT()' did not work properly as an argument to a stored
     procedure.  (Bug #23760)

   * `LAST_DAY('0000-00-00')' could cause a server crash.  (Bug #23653)

   * A trigger that invoked a stored function could cause a server
     crash when activated by different client connections.  (Bug #23651)

   * The stack size for NetWare binaries was increased to 128KB to
     prevent problems caused by insufficient stack size.  (Bug #23504)

   * If elements in a nontop-level `IN' subquery were accessed by an
     index and the subquery result set included a `NULL' value, the
     quantified predicate that contained the subquery was evaluated to
     `NULL' when it should return a non-`NULL' value.  (Bug #23478)

   * When applying the `group_concat_max_len' limit, `GROUP_CONCAT()'
     could truncate multi-byte characters in the middle.  (Bug #23451)

   * *Note `mysql_affected_rows()': mysql-affected-rows. could return
     values different from *Note `mysql_stmt_affected_rows()':
     mysql-stmt-affected-rows. for the same sequence of statements.
     (Bug #23383)

   * Accuracy was improved for comparisons between *Note `DECIMAL':
     numeric-types. columns and numbers represented as strings.  (Bug
     #23260)

   * Calculation of `COUNT(DISTINCT)', `AVG(DISTINCT)', or
     `SUM(DISTINCT)' when they are referenced more than once in a
     single query with `GROUP BY' could cause a server crash.  (Bug
     #23184)

   * Queries using a column alias in an expression as part of an `ORDER
     BY' clause failed, an example of such a query being `SELECT mycol
     + 1 AS mynum FROM mytable ORDER BY 30 - mynum'.  (Bug #22457)

   * Using *Note `EXPLAIN': explain. caused a server crash for queries
     that selected from `INFORMATION_SCHEMA' in a subquery in the
     `FROM' clause.  (Bug #22413)

   * A server crash occurred when using *Note `LOAD DATA': load-data.
     to load a table containing a `NOT NULL' spatial column, when the
     statement did not load the spatial column. Now a `NULL supplied to
     NOT NULL column' error occurs.  (Bug #22372)

   * `DATE_ADD()' requires complete dates with no `zero' parts, but
     sometimes did not return `NULL' when given such a date.  (Bug
     #22229)

   * Some small double precision numbers (such as `1.00000001e-300')
     that should have been accepted were truncated to zero.  (Bug
     #22129)

   * For a nonexistent table, `DROP TEMPORARY TABLE' failed with an
     incorrect error message if `read_only' was enabled.  (Bug #22077)

   * Trailing spaces were not removed from Unicode *Note `CHAR': char.
     column values when used in indexes. This resulted in excessive
     usage of storage space, and could affect the results of some
     `ORDER BY' queries that made use of such indexes.

     *Note*:

     When upgrading, it is necessary to re-create any existing indexes
     on Unicode *Note `CHAR': char. columns of each affected table to
     take advantage of the fix. See *Note rebuilding-tables::.

     (Bug #22052)

   * `STR_TO_DATE()' returned `NULL' if the format string contained a
     space following a nonformat character.  (Bug #22029)

   * In some cases, the parser failed to distinguish a user-defined
     function from a stored function.  (Bug #21809)

   * Inserting a default or invalid value into a spatial column could
     fail with `Unknown error' rather than a more appropriate error.
     (Bug #21790)

   * It was possible to use *Note `DATETIME': datetime.  values whose
     year, month, and day parts were all zeros but whose hour, minute,
     and second parts contained nonzero values, an example of such an
     illegal *Note `DATETIME': datetime. being `'0000-00-00 11:23:45''.

     *Note*:

     This fix was reverted in MySQL 5.0.40.

     (Bug #21789) See also Bug #25301.

   * yaSSL crashed on pre-Pentium Intel CPUs.  (Bug #21765)

   * Through the C API, the member strings in `MYSQL_FIELD' for a query
     that contained expressions could return incorrect results.  (Bug
     #21635)

   * Using *Note `FLUSH TABLES': flush. in one connection while another
     connection is using *Note `HANDLER': handler. statements caused a
     server crash.

     *Note*:

     This fix was reverted in MySQL 5.0.48

     (Bug #21587) See also Bug #29474.

   * View columns were always handled as having implicit derivation,
     leading to `illegal mix of collation errors' for some views in
     *Note `UNION': union.  operations. Now view column derivation
     comes from the original expression given in the view definition.
     (Bug #21505)

   * `InnoDB' crashed while performing XA recovery of prepared
     transactions.  (Bug #21468)

   * `INET_ATON()' returned a signed *Note `BIGINT': numeric-types.
     value, not an unsigned value.  (Bug #21466)

   * It was possible to set the backslash character (``\'') as the
     delimiter character using `DELIMITER', but not actually possible to
     use it as the delimiter.  (Bug #21412)

   * Selecting into variables sometimes returned incorrect wrong
     results.  (Bug #20836)

   * `CONCURRENT' did not work correctly for *Note `LOAD DATA INFILE':
     load-data.  (Bug #20637)

   * `mysql_fix_privilege_tables.sql' altered the
     `table_privs.table_priv' column to contain too few privileges,
     causing loss of the *Note `CREATE VIEW': create-view. and `SHOW
     VIEW' privileges.  (Bug #20589)

   * With `lower_case_table_names' set to 1, *Note `SHOW CREATE TABLE':
     show-create-table. printed incorrect output for table names
     containing Turkish I (LATIN CAPITAL LETTER I WITH DOT ABOVE).
     (Bug #20404)

   * A query with a subquery that references columns of a view from the
     outer *Note `SELECT': select. could return an incorrect result if
     used from a prepared statement.  (Bug #20327)

   * For queries that select from a view, the server returned
     `MYSQL_FIELD' metadata inconsistently for view names and table
     names. For view columns, the server now returns the view name in
     the `table' field and, if the column selects from an underlying
     table, the table name in the `org_table' field.  (Bug #20191)

   * Invalidating the query cache caused a server crash for *Note
     `INSERT INTO ... SELECT': insert-select. statements that selected
     from a view.  (Bug #20045)

   * Unsigned *Note `BIGINT': numeric-types. values treated as signed
     values by the `MOD()' function.  (Bug #19955)

   * Compiling PHP 5.1 with the MySQL static libraries failed on some
     versions of Linux.  (Bug #19817)

   * The `DELIMITER' statement did not work correctly when used in an
     SQL file run using the `SOURCE' statement.  (Bug #19799)

   * For a cast of a *Note `DATETIME': datetime. value containing
     microseconds to *Note `DECIMAL': numeric-types, the microseconds
     part was truncated without generating a warning. Now the
     microseconds part is preserved.  (Bug #19491)

   * *Note `VARBINARY': binary-varbinary. column values inserted on a
     MySQL 4.1 server had trailing zeros following upgrade to MySQL 5.0
     or later.  (Bug #19371)

   * The server could send incorrect column count information to the
     client for queries that produce a larger number of columns than
     can fit in a two-byte number.  (Bug #19216)

   * For some problems relating to character set conversion or
     incorrect string values for *Note `INSERT': insert. or *Note
     `UPDATE': update, the server reported truncation or length errors
     instead.  (Bug #18908)

   * Constant expressions and some numeric constants used as input
     parameters to user-defined functions were not treated as constants.
     (Bug #18761)

   * *Note `myisampack': myisampack. wrote to unallocated memory,
     causing a crash.  (Bug #17951)

   * *Note `FLUSH LOGS': flush. or *Note `mysqladmin flush-logs':
     mysqladmin. caused a server crash if the binary log was not open.
     (Bug #17733)

   * *Note `mysql_fix_privilege_tables': mysql-fix-privilege-tables.
     did not accept a password containing embedded space or apostrophe
     characters.  (Bug #17700)

   * Attempting to use a view containing `DEFINER' information for a
     nonexistent user resulted in an error message that revealed the
     definer account. Now the definer is revealed only to users that
     have the `SUPER' privilege. Other users receive only an `access
     denied' message.  (Bug #17254)

   * `IN()' and `CHAR()' can return `NULL', but did not signal that to
     the query processor, causing incorrect results for `IS NULL'
     operations.  (Bug #17047)

   * Warnings were generated when explicitly casting a character to a
     number (for example, `CAST('x' AS SIGNED)'), but not for implicit
     conversions in simple arithmetic operations (such as `'x' + 0').
     Now warnings are generated in all cases.  (Bug #11927)

   * Metadata for columns calculated from scalar subqueries was limited
     to integer, double, or string, even if the actual type of the
     column was different.  (Bug #11032)

   * Subqueries of the form `NULL IN (SELECT ...)' returned invalid
     results.  (Bug #8804, Bug #23485)


File: manual.info,  Node: news-5-0-30sp1,  Next: news-5-0-30,  Prev: news-5-0-32,  Up: news-5-0-x

D.1.65 Changes in MySQL Enterprise 5.0.30sp1 [QSP] (19 January 2007)
--------------------------------------------------------------------

This is a _Service Pack_ release of the MySQL Enterprise Server 5.0.

This section documents all changes and bug fixes that have been applied
since the last MySQL Enterprise Server release (5.0.30).

*Functionality Added or Changed*

   * *Incompatible Change*: `InnoDB' rolls back only the last statement
     on a transaction timeout. A new option,
     `--innodb_rollback_on_timeout', causes `InnoDB' to abort and roll
     back the entire transaction if a transaction timeout occurs (the
     same behavior as in MySQL 5.0.13 and earlier).  (Bug #24200)

*Bugs Fixed*

   * *Performance*: Evaluation of subqueries that require the filesort
     algorithm were allocating and freeing the `sort_buffer_size'
     buffer many times, resulting in slow performance. Now the buffer is
     allocated once and reused.  (Bug #21727)

   * *Replication*: A stored procedure, executed from a connection
     using a binary character set, and which wrote multibyte data,
     would write incorrectly escaped entries to the binary log. This
     caused syntax errors, and caused replication to fail.  (Bug
     #23619, Bug #24492)

   * The loose index scan optimization for `GROUP BY' with `MIN' or
     `MAX' was not applied within other queries, such as *Note `CREATE
     TABLE ... SELECT ...': create-table, `INSERT ... SELECT ...', or
     in the `FROM' clauses of subqueries.  (Bug #24156)

   * The size of `MEMORY' tables and internal temporary tables was
     limited to 4GB on 64-bit Windows systems.  (Bug #24052)

   * Accuracy was improved for comparisons between *Note `DECIMAL':
     numeric-types. columns and numbers represented as strings.  (Bug
     #23260)

   * Calculation of `COUNT(DISTINCT)', `AVG(DISTINCT)', or
     `SUM(DISTINCT)' when they are referenced more than once in a
     single query with `GROUP BY' could cause a server crash.  (Bug
     #23184)

   * `InnoDB' crashed while performing XA recovery of prepared
     transactions.  (Bug #21468)

   * Certain malformed *Note `INSERT': insert.  statements could crash
     the *Note `mysql': mysql. client.  (Bug #21142)

   * `CONCURRENT' did not work correctly for *Note `LOAD DATA INFILE':
     load-data.  (Bug #20637)

   * Several string functions could return incorrect results when given
     very large length arguments.  (Bug #10963)


File: manual.info,  Node: news-5-0-30,  Next: news-5-0-28,  Prev: news-5-0-30sp1,  Up: news-5-0-x

D.1.66 Changes in MySQL Enterprise 5.0.30 [MRU] (14 November 2006)
------------------------------------------------------------------

This is a _Monthly Rapid Update_ release of the MySQL Enterprise Server
5.0.

This section documents all changes and bug fixes that have been applied
since the last MySQL Enterprise Server release (5.0.28).

*Functionality Added or Changed*

   * *MySQL Cluster*: The *Note `ndb_config':
     mysql-cluster-programs-ndb-config. utility now accepts `-c' as a
     short form of the `--ndb-connectstring' option.  (Bug #22295)

   * *MySQL Cluster*: Added the `--bind-address' option for *Note
     `ndbd': mysql-cluster-programs-ndbd. This permits a data node
     process to be bound to a specific network interface.  (Bug #22195)

   * *MySQL Cluster*: The *Note `NDB': mysql-cluster. storage engine
     could leak memory during file operations.  (Bug #21858)

   * *MySQL Cluster*: The `Ndb_number_of_storage_nodes' system variable
     was renamed to `Ndb_number_of_data_nodes'.  (Bug #20848)

   * *MySQL Cluster*: The *Note `HELP': help. command in the Cluster
     management client now provides command-specific help. For example,
     `HELP RESTART' in *Note `ndb_mgm': mysql-cluster-programs-ndb-mgm.
     provides detailed information about the `RESTART' command.  (Bug
     #19620)

   * If the user specified the server options `--max-connections=N ' or
     `--table-cache=M ', a warning would be given in some cases that
     some values were recalculated, with the result that
     `--table-cache' could be assigned greater value.

     In such cases, both the warning and the increase in the
     `--table-cache' value were completely harmless. Note also that it
     is not possible for the MySQL Server to predict or to control
     limitations on the maximum number of open files, since this is
     determined by the operating system.

     The value of `--table-cache' is no longer increased automatically,
     and a warning is now given only if some values had to be decreased
     due to operating system limits.  (Bug #21915)

   * For the *Note `CALL': call. statement, stored procedures that take
     no arguments now can be invoked without parentheses. That is,
     `CALL p()' and `CALL p' are equivalent.  (Bug #21462)

   * `mysql_upgrade' now passes all the parameters specified on the
     command line to both `mysqlcheck' and `mysql' using the
     `upgrade_defaults' file.  (Bug #20100)

   * *Note `SHOW STATUS': show-status. is no longer logged to the slow
     query log.  (Bug #19764)

   * *Note `mysqldump --single-transaction': mysqldump. now uses `START
     TRANSACTION /*!40100 WITH CONSISTENT SNAPSHOT */' rather than
     *Note `BEGIN': commit. to start a transaction, so that a
     consistent snapshot will be used on those servers that support it.
     (Bug #19660)

*Bugs Fixed*

   * *Performance*: `InnoDB' exhibited thread thrashing with more than
     50 concurrent connections under an update-intensive workload.
     (Bug #22868)

   * *Performance*: `InnoDB' showed substandard performance with
     multiple queries running concurrently.  (Bug #15815)

   * *MySQL Cluster*: Backup of a cluster failed if there were any
     tables with 128 or more columns.  (Bug #23502)

   * *MySQL Cluster*: Cluster backups failed when there were more than
     2048 schema objects in the cluster.  (Bug #23499)

   * *MySQL Cluster*: The management client command `ALL DUMP 1000'
     would cause the cluster to crash if data nodes were connected to
     the cluster but not yet fully started.  (Bug #23203)

   * *MySQL Cluster*: *Note `INSERT ... ON DUPLICATE KEY UPDATE':
     insert-on-duplicate. on an *Note `NDB': mysql-cluster. table could
     lead to deadlocks and memory leaks.  (Bug #23200)

   * *MySQL Cluster*: (NDB API): Inacivity timeouts for scans were not
     correctly handled.  (Bug #23107)

   * *MySQL Cluster*: If a node restart could not be performed from the
     REDO log, no node takeover took place. This could cause partitions
     to be left empty during a system restart.  (Bug #22893)

   * *MySQL Cluster*: Multiple node restarts in rapid succession could
     cause a system restart to fail , or induce a race condition.  (Bug
     #22892, Bug #23210)

   * *MySQL Cluster*: (NDB API): Attempting to read a nonexistent tuple
     using `Commit' mode for `NdbTransaction::execute()' caused node
     failures.  (Bug #22672)

   * *MySQL Cluster*: The `--help' output from *Note `NDB':
     mysql-cluster. binaries did not include file-related options.
     (Bug #21994)

   * *MySQL Cluster*: (NDB API): Scans closed before being executed
     were still placed in the send queue.  (Bug #21941)

   * *MySQL Cluster*: A scan timeout returned Error 4028 (`Node failure
     caused abort of transaction') instead of Error 4008 (`Node failure
     caused abort of transaction...').  (Bug #21799)

   * *MySQL Cluster*: The node recovery algorithm was missing a version
     check for tables in the `ALTER_TABLE_COMMITTED' state (as opposed
     to the `TABLE_ADD_COMMITTED' state, which has the version check).
     This could cause inconsistent schemas across nodes following node
     recovery.  (Bug #21756)

   * *MySQL Cluster*: Partition distribution keys were updated only for
     the primary and starting replicas during node recovery. This could
     lead to node failure recovery for clusters having an odd number of
     replicas.

     *Note*:

     For best results, use values for `NumberOfReplicas' that are even
     powers of 2.

     (Bug #21535)

   * *MySQL Cluster*: The *Note `ndb_mgm':
     mysql-cluster-programs-ndb-mgm. management client did not set the
     exit status on errors, always returning 0 instead.  (Bug #21530)

   * *MySQL Cluster*: Attempting to create an *Note `NDB':
     mysql-cluster. table on a MySQL with an existing non-Cluster table
     with the same name in the same database could result in data loss
     or corruption.  MySQL now issues a warning when a *Note `SHOW
     TABLES': show-tables. or other statement causing table discovery
     finds such a table.  (Bug #21378)

   * *MySQL Cluster*: Cluster logs were not rotated following the first
     rotation cycle.  (Bug #21345)

   * *MySQL Cluster*: When inserting a row into an *Note `NDB':
     mysql-cluster.  table with a duplicate value for a nonprimary
     unique key, the error issued would reference the wrong key.  (Bug
     #21072)

   * *MySQL Cluster*: Condition pushdown did not work correctly with
     *Note `DATETIME': datetime. columns.  (Bug #21056)

   * *MySQL Cluster*: Under some circumstances, local checkpointing
     would hang, keeping any unstarted nodes from being started.  (Bug
     #20895)

   * *MySQL Cluster*: Using an invalid node ID with the management
     client `STOP' command could cause *Note `ndb_mgm':
     mysql-cluster-programs-ndb-mgm. to hang.  (Bug #20575)

   * *MySQL Cluster*: Data nodes added while the cluster was running in
     single user mode were all assigned node ID 0, which could later
     cause multiple node failures. Adding nodes while in single user
     mode is no longer possible.  (Bug #20395)

   * *MySQL Cluster*: In some cases where `SELECT COUNT(*)' from an
     *Note `NDB': mysql-cluster. table should have yielded an error,
     `MAX_INT' was returned instead.  (Bug #19914)

   * *MySQL Cluster*: Following the restart of a management node, the
     Cluster management client did not automatically reconnect.  (Bug
     #19873)

   * *MySQL Cluster*: Error messages given when trying to make online
     changes to parameters such as `NoOfReplicas' that can only be
     changed using a complete shutdown and restart of the cluster did
     not indicate the true nature of the problem.  (Bug #19787)

   * *MySQL Cluster*: *Note `ndb_restore':
     mysql-cluster-programs-ndb-restore. did not always make clear that
     it had recovered successfully from temporary errors while restoring
     a cluster backup.  (Bug #19651)

   * *MySQL Cluster*: In rare situations with resource shortages, a
     crash could result from an insufficient number of
     `IndexScanOperation' objects.  (Bug #19198)

   * *MySQL Cluster*: *Note `ndb_mgm -e show | head':
     mysql-cluster-programs-ndb-mgm. would hang after displaying the
     first 10 lines of output.  (Bug #19047)

   * *MySQL Cluster*: The error returned by the cluster when too many
     nodes were defined did not make clear the nature of the problem.
     (Bug #19045)

   * *MySQL Cluster*: The *Note `ndb_config':
     mysql-cluster-programs-ndb-config. utility did not perform host
     lookups correctly when using the `--host' option (Bug #17582)

   * *MySQL Cluster*: A problem with takeover during a system restart
     caused ordered indexes to be rebuilt incorrectly.  (Bug #15303)

   * *Replication*: Column names were not quoted properly for
     replicated views.  (Bug #19736)

   * *Replication*: Transient errors in replication from master to
     slave may trigger multiple `Got fatal error 1236: 'binlog
     truncated in the middle of event'' errors on the slave.  (Bug
     #4053)

   * *Cluster API*: The `NdbOperation::getBlobHandle()' method, when
     called with the name of a nonexistent column, caused a
     segmentation fault.  (Bug #21036)

   * *Cluster API*: When multiple processes or threads in parallel
     performed the same ordered scan with exclusive lock and updated
     the retrieved records, the scan could skip some records, which as
     a result were not updated.  (Bug #20446)

   * There was a race condition in the `InnoDB'
     `fil_flush_file_spaces()' function.  (Bug #24089) This regression
     was introduced by Bug #15653.

   * yaSSL-related memory leaks were detected by Valgrind.  (Bug #23981)

   * The internal SQL interpreter of `InnoDB' placed an unnecessary
     lock on the supremum record with `innodb_locks_unsafe_for_binlog'
     enabled. This caused an assertion failure when `InnoDB' was built
     with debugging enabled.  (Bug #23769)

   * `M % 0' returns `NULL', but (` M % 0) IS NULL' evaluated to false.
     (Bug #23411)

   * For not-yet-authenticated connections, the `Time' column in *Note
     `SHOW PROCESSLIST': show-processlist. was a random value rather
     than `NULL'.  (Bug #23379)

   * MySQL failed to build on Linux/Alpha.  (Bug #23256) This
     regression was introduced by Bug #21250.

   * If `COMPRESS()' returned `NULL', subsequent invocations of
     `COMPRESS()' within a result set or within a trigger also returned
     `NULL'.  (Bug #23254)

   * Insufficient memory (`myisam_sort_buffer_size') could cause a
     server crash for several operations on `MyISAM' tables: repair
     table, create index by sort, repair by sort, parallel repair, bulk
     insert.  (Bug #23175)

   * The column default value in the output from *Note `SHOW COLUMNS':
     show-columns. or `SELECT FROM INFORMATION_SCHEMA.COLUMNS' was
     truncated to 64 characters.  (Bug #23037)

   * *Note `mysql': mysql. did not check for errors when fetching data
     during result set printing.  (Bug #22913)

   * The return value from `my_seek()' was ignored.  (Bug #22828)

   * The optimizer failed to use equality propagation for `BETWEEN' and
     `IN' predicates with string arguments.  (Bug #22753)

   * The `Handler_rollback' status variable sometimes was incremented
     when no rollback had taken place.  (Bug #22728)

   * The `Host' column in *Note `SHOW PROCESSLIST': show-processlist.
     output was blank when the server was started with the
     `--skip-grant-tables' option.  (Bug #22723)

   * If a table contains an `AUTO_INCREMENT' column, inserting into an
     insertable view on the table that does not include the
     `AUTO_INCREMENT' column should not change the value of
     `LAST_INSERT_ID()', because the side effects of inserting default
     values into columns not part of the view should not be visible.
     MySQL was incorrectly setting `LAST_INSERT_ID()' to zero.  (Bug
     #22584)

   * Instance Manager had a race condition involving ` mysqld' PID file
     removal.  (Bug #22379)

   * The optimizer used the `ref' join type rather than `eq_ref' for a
     simple join on strings.  (Bug #22367)

   * Some queries that used `MAX()' and `GROUP BY' could incorrectly
     return an empty result.  (Bug #22342)

   * If an `init_connect' SQL statement produced an error, the
     connection was silently terminated with no error message. Now the
     server writes a warning to the error log.  (Bug #22158)

   * Use of a DES-encrypted SSL certificate file caused a server crash.
     (Bug #21868)

   * Use of *Note `PREPARE': prepare. with a *Note `CREATE PROCEDURE':
     create-procedure. statement that contained a syntax error caused a
     server crash.  (Bug #21856)

   * Adding a day, month, or year interval to a *Note `DATE': datetime.
     value produced a *Note `DATE': datetime, but adding a week interval
     produced a *Note `DATETIME': datetime. value. Now all produce a
     *Note `DATE': datetime. value.  (Bug #21811)

   * Use of a subquery that invoked a function in the column list of
     the outer query resulted in a memory leak.  (Bug #21798)

   * Selecting from a `MERGE' table could result in a server crash if
     the underlying tables had fewer indexes than the `MERGE' table
     itself.  (Bug #21617, Bug #22937)

   * After *Note `FLUSH TABLES WITH READ LOCK': flush. followed by
     *Note `UNLOCK TABLES': lock-tables, attempts to drop or alter a
     stored routine failed with an error that the routine did not
     exist, and attempts to execute the routine failed with a lock
     conflict error.  (Bug #21414)

   * For multiple-table *Note `UPDATE': update.  statements, storage
     engines were not notified of duplicate-key errors.  (Bug #21381)

   * Within a prepared statement, `SELECT (COUNT(*) = 1)' (or similar
     use of other aggregate functions) did not return the correct
     result for statement re-execution.  (Bug #21354)

   * It was possible for a stored routine with a non-`latin1' name to
     cause a stack overrun.  (Bug #21311)

   * Creating a `TEMPORARY' table with the same name as an existing
     table that was locked by another client could result in a lock
     conflict for `DROP TEMPORARY TABLE' because the server
     unnecessarily tried to acquire a name lock.  (Bug #21096)

   * Incorrect results could be obtained from re-execution of a
     parametrized prepared statement or a stored routine with a *Note
     `SELECT': select. that uses `LEFT JOIN' with a second table having
     only one row.  (Bug #21081)

   * Within a stored routine, a view definition cannot refer to routine
     parameters or local variables. However, an error did not occur
     until the routine was called. Now it occurs during parsing of the
     routine creation statement.

     *Note*:

     A side effect of this fix is that if you have already created such
     routines, and error will occur if you execute *Note `SHOW CREATE
     PROCEDURE': show-create-procedure. or *Note `SHOW CREATE
     FUNCTION': show-create-function. You should drop these routines
     because they are erroneous.

     (Bug #20953)

   * In *Note `mysql': mysql, invoking `connect' or `\r' with very long
     DB_NAME or HOST_NAME parameters caused buffer overflow.  (Bug
     #20894)

   * *Note `SHOW VARIABLES': show-variables. truncated the `Value'
     field to 256 characters.  (Bug #20862)

   * `WITH ROLLUP' could group unequal values.  (Bug #20825)

   * Range searches on columns with an index prefix could miss records.
     (Bug #20732)

   * An *Note `UPDATE': update. that referred to a key column in the
     `WHERE' clause and activated a trigger that modified the column
     resulted in a loop.  (Bug #20670)

   * `LIKE' searches failed for indexed `utf8' character columns.  (Bug
     #20471)

   * With `sql_mode = TRADITIONAL', MySQL incorrectly aborted on
     warnings within stored routines and triggers.  (Bug #20028)

   * *Note `mysqldump --xml': mysqldump. produced invalid XML for *Note
     `BLOB': blob. data.  (Bug #19745)

   * `FLUSH INSTANCES' in Instance Manager triggered an assertion
     failure.  (Bug #19368)

   * For a debug server, a reference to an undefined user variable in a
     prepared statement executed with *Note `EXECUTE': execute. caused
     an assertion failure.  (Bug #19356)

   * Within a trigger for a base table, selecting from a view on that
     base table failed.  (Bug #19111)

   * The value of the `warning_count' system variable was not being
     calculated correctly (also affecting *Note `SHOW COUNT(*)
     WARNINGS': show-warnings.).  (Bug #19024)

   * `DELETE IGNORE' could hang for foreign key parent deletes.  (Bug
     #18819)

   * `InnoDB' used table locks (not row locks) within stored functions.
     (Bug #18077)

   * *Note `mysql': mysql. would lose its connection to the server if
     its standard output was not writable.  (Bug #17583)

   * `mysql-test-run' did not work correctly for RPM-based
     installations.  (Bug #17194)

   * A client library crash was caused by executing a statement such as
     `SELECT * FROM t1 PROCEDURE ANALYSE()' using a server side cursor
     on a table `t1' that does not have the same number of columns as
     the output from `PROCEDURE ANALYSE()'.  (Bug #17039)

   * The `WITH CHECK OPTION' for a view failed to prevent storing
     invalid column values for *Note `UPDATE': update. statements.
     (Bug #16813)

   * *Note `ALTER TABLE': alter-table. was not able to rename a view.
     (Bug #14959)

   * Statements such as *Note `DROP PROCEDURE': drop-procedure.  and
     *Note `DROP VIEW': drop-view. were written to the binary log too
     late due to a race condition.  (Bug #14262)

   * A literal string in a `GROUP BY' clause could be interpreted as a
     column name.  (Bug #14019)

   * Instance Manager didn't close the client socket file when starting
     a new *Note `mysqld': mysqld. instance.  *Note `mysqld': mysqld.
     inherited the socket, causing clients connected to Instance
     Manager to hang.  (Bug #12751)

   * Entries in the slow query log could have an incorrect
     `Rows_examined' value.  (Bug #12240)

   * Lack of validation for input and output *Note `TIME': time. values
     resulted in several problems: `SEC_TO_TIME()' in some cases did
     not clip large values to the *Note `TIME': time. range
     appropriately; `SEC_TO_TIME()' treated `BIGINT UNSIGNED' values as
     signed; only truncation warnings were produced when both
     truncation and out-of-range *Note `TIME': time. values occurred.
     (Bug #11655, Bug #20927)

   * A locking safety check in `InnoDB' reported a spurious error
     `stored_select_lock_type is 0 inside ::start_stmt()' for *Note
     `INSERT ... SELECT': insert-select. statements in
     `innodb_locks_unsafe_for_binlog' mode. The safety check was
     removed.  (Bug #10746)

   * `FROM_UNIXTIME()' did not accept arguments up to `POWER(2,31)-1',
     which it had previously.  (Bug #9191)

   * *Note `OPTIMIZE TABLE': optimize-table. with
     `myisam_repair_threads' > 1 could result in `MyISAM' table
     corruption.  (Bug #8283)


File: manual.info,  Node: news-5-0-28,  Next: news-5-0-27,  Prev: news-5-0-30,  Up: news-5-0-x

D.1.67 Changes in MySQL Enterprise 5.0.28 (24 October 2006)
-----------------------------------------------------------

This is the first _MySQL Enterprise Server_ release, following the last
Community Server release (5.0.27).

*Functionality Added or Changed*

   * Binary MySQL distributions no longer include a `mysqld-max'
     server, except for RPM distributions. Instead, distributions
     contain a *Note `mysqld': mysqld. binary that includes the features
     previously included in the `mysqld-max' binary.

*Bugs Fixed*

   * MySQL 5.0.26 introduced an ABI incompatibility, which this release
     reverts. Programs compiled against 5.0.26 are not compatible with
     any other version and must be recompiled.  (Bug #23427)

   * `InnoDB': Reduced optimization level for Windows 64 builds to
     handle possible memory overrun.  (Bug #19424)


File: manual.info,  Node: news-5-0-27,  Next: news-5-0-26,  Prev: news-5-0-28,  Up: news-5-0-x

D.1.68 Changes in MySQL Community Server 5.0.27 (21 October 2006)
-----------------------------------------------------------------

This is a bugfix release for the current MySQL Community Server
production release family. It replaces MySQL 5.0.26.

*Functionality Added or Changed*

   * This is the last version for which binary MySQL-Max distributions
     are available, except for RPM distributions. (For RPM
     distributions, the last version is 5.0.37.)

*Bugs Fixed*

   * MySQL 5.0.26 introduced an ABI incompatibility, which this release
     reverts. Programs compiled against 5.0.26 are not compatible with
     any other version and must be recompiled.  (Bug #23427)


File: manual.info,  Node: news-5-0-26,  Next: news-5-0-25,  Prev: news-5-0-27,  Up: news-5-0-x

D.1.69 Changes in MySQL 5.0.26 (03 October 2006)
------------------------------------------------

This is a bugfix release for the current production release family.

This section documents all changes and bug fixes that have been applied
since the last official MySQL release. If you would like to receive
more fine-grained and personalized _update alerts_ about fixes that are
relevant to the version and features you use, please consider
subscribing to _MySQL Enterprise_ (a commercial MySQL offering). For
more details, please see http://www.mysql.com/products/enterprise.

*Functionality Added or Changed*

   * *Important Change*: *MySQL Cluster*: *Note `LOAD DATA INFILE':
     load-data. no longer causes an implicit commit for all storage
     engines. It now causes an implicit commit only for tables using
     the *Note `NDB': mysql-cluster. storage engine.  (Bug #11151)

   * The number of `InnoDB' threads is no longer limited to 1,000 on
     Windows.  (Bug #22268)

   * *Note `mysqldump': mysqldump. now has a `--flush-privileges'
     option. It causes *Note `mysqldump': mysqldump. to emit a *Note
     `FLUSH PRIVILEGES': flush. statement after dumping the `mysql'
     database. This option should be used any time the dump contains
     the `mysql' database and any other database that depends on the
     data in the `mysql' database for proper restoration.  (Bug #21424)

   * For *Note `mysqldump': mysqldump, the output generated by the
     server when using the `--xml' option has changed with regard to
     null values. It now matches the output from *Note `mysqldump':
     mysqldump.  `--xml'. That is, a column containing a `NULL' value
     is now reported as

          <field name="COLUMN_NAME" xsi:nil="true" />

     whereas a column containing the string value `'NULL'' is reported
     as

          <field name="COLUMN_NAME">NULL</field>

     and a column containing an empty string is reported as

          <field name="COLUMN_NAME"></field>

     (Bug #21263)

   * The source distribution has been updated so that the UDF example
     can be compiled under Windows with `CMake'. See *Note
     udf-compiling::.  (Bug #19121)

   * The `LOAD DATA FROM MASTER' and `LOAD TABLE FROM MASTER'
     statements are deprecated. See *Note load-data-from-master::, for
     recommended alternatives.  (Bug #9125, Bug #20596, Bug #14399, Bug
     #12187, Bug #15025, Bug #18822)

*Bugs Fixed*

   * *Replication*: Column names supplied for a view created on a
     master server could be lost on a slave server.  (Bug #19419)

   * Deleting entries from a large `MyISAM' index could cause index
     corruption when it needed to shrink. Deletes from an index can
     happen when a record is deleted, when a key changes and must be
     moved, and when a key must be un-inserted because of a duplicate
     key. This can also happen in *Note `REPAIR TABLE': repair-table.
     when a duplicate key is found and in *Note `myisamchk': myisamchk.
     when sorting the records by an index.  (Bug #22384)

   * yaSSL had a conflicting definition for `socklen_t' on hurd-i386
     systems.  (Bug #22326)

   * Conversion of values inserted into a *Note `BIT': numeric-types.
     column could affect adjacent columns.  (Bug #22271)

   * `mysql_com.h' unnecessarily referred to the `ulong' type.  (Bug
     #22227)

   * The source distribution would not build on Windows due to a
     spurious dependency on `ib_config.h'.  (Bug #22224)

   * Execution of a prepared statement that uses an `IN' subquery with
     aggregate functions in the `HAVING' clause could cause a server
     crash.  (Bug #22085)

   * Using `GROUP_CONCAT()' on the result of a subquery in the `FROM'
     clause that itself used `GROUP_CONCAT()' could cause a server
     crash.  (Bug #22015)

   * A query that used `GROUP BY' and an `ALL' or `ANY' quantified
     subquery in a `HAVING' clause could trigger an assertion failure.
     (Bug #21853)

   * `UPGRADE' was treated as a reserved word, although it is not.
     (Bug #21772)

   * The value of `LAST_INSERT_ID()' was not always updated correctly
     within stored routines.  (Bug #21726)

   * A function result in a comparison was replaced with a constant by
     the optimizer under some circumstances when this optimization was
     invalid.  (Bug #21698)

   * If `mysqld' was linked against a system-installed `zlib' library
     compiled without large-file support, it would likely exit with a
     `SIGXFSZ' (file size exceeded) signal if an `ARCHIVE' table
     reached 2GB. The server now checks for space before writing.  (Bug
     #21675)

   * The presence of a subquery in the `ON' clause of a join in a view
     definition prevented the `MERGE' algorithm from being used for the
     view in cases where it should be permitted.  (Bug #21646)

   * When records are merged from the insert buffer and the page needs
     to be reorganized, `InnoDB' used incorrect column length
     information when interpreting the records of the page. This caused
     a server crash due to apparent corruption of secondary indexes in
     `ROW_FORMAT=COMPACT' that contain prefix indexes of fixed-length
     columns. Data files should not be corrupted, but the crash was
     likely to repeat every time the server was restarted.  (Bug #21638)

   * For character sets having a `mbmaxlen' value of 2, any *Note
     `ALTER TABLE': alter-table. statement changed *Note `TEXT': blob.
     columns to *Note `MEDIUMTEXT': blob.  (Bug #21620)

   * *Note `mysql': mysql. displayed an empty string for `NULL' values.
     (Bug #21618)

   * For *Note `INSERT ... ON DUPLICATE KEY UPDATE':
     insert-on-duplicate, use of `VALUES(COL_NAME)' within the *Note
     `UPDATE': update. clause sometimes was handled incorrectly.  (Bug
     #21555)

   * Subqueries with aggregate functions but no `FROM' clause could
     return incorrect results.  (Bug #21540)

   * The server could crash for the second execution of a function
     containing a *Note `SELECT': select. statement that uses an
     aggregating `IN' subquery.  (Bug #21493)

   * *Note `myisam_ftdump': myisam-ftdump. produced bad counts for
     common words.  (Bug #21459)

   * The URL into the online manual that is printed in the stack trace
     message by the server was out of date.  (Bug #21449)

   * Table aliases in multiple-table *Note `DELETE': delete. statements
     sometimes were not resolved.  (Bug #21392)

   * *Note `mysql_config --libmysqld-libs': mysql-config. did not
     produce any SSL options necessary for linking `libmysqld' with SSL
     support enabled.  (Bug #21239)

   * In the package of pre-built time zone tables that is available for
     download at `http://dev.mysql.com/downloads/timezones.html', the
     tables now explicitly use the `utf8' character set so that they
     work the same way regardless of the system character set value.
     (Bug #21208)

   * A subquery that uses an index for both the `WHERE' and `ORDER BY'
     clauses produced an empty result.  (Bug #21180)

   * *Note `mysql_upgrade': mysql-upgrade. produced a malformed
     `upgrade_defaults' file by overwriting the `[client]' group header
     with a `password' option. This prevented *Note `mysqlcheck':
     mysqlcheck. from running successfully when invoked by *Note
     `mysql_upgrade': mysql-upgrade.  (Bug #21011)

   * On Windows, inserting into a `MERGE' table after renaming an
     underlying `MyISAM' table caused a server crash.  (Bug #20789)

   * Within stored routines, some error messages were printed
     incorrectly. A nonnull-terminated string was passed to a
     message-printing routine that expected a null-terminated string.
     (Bug #20778)

   * *Note `INSERT DELAYED': insert-delayed. did not honor `SET
     INSERT_ID' or the `auto_increment_*' system variables.  (Bug
     #20627, Bug #20830)

   * If the `auto_increment_offset' setting causes MySQL to generate a
     value larger than the column's maximum possible value, the *Note
     `INSERT': insert. statement is accepted in strict SQL mode,
     whereas but should fail with an error.  (Bug #20573)

   * User names have a maximum length of 16 characters (even if they
     contain multi-byte characters), but were being truncated to 16
     bytes.  (Bug #20393)

   * `PROCEDURE ANALYSE()' returned incorrect values of M `FLOAT(M, D)'
     and `DOUBLE(M, D)'.  (Bug #20305)

   * For a `MyISAM' table locked with `LOCK TABLES ...WRITE', queries
     optimized using the `index_merge' method did not show rows
     inserted with the lock in place.  (Bug #20256)

   * `SUBSTRING()' results sometimes were stored improperly into a
     temporary table when multi-byte character sets were used.  (Bug
     #20204)

   * For an *Note `ENUM': enum. column that used the `ucs2' character
     set, using *Note `ALTER TABLE': alter-table. to modify the column
     definition caused the default value to be lost.  (Bug #20108)

   * Join conditions using index prefixes on `utf8' columns of `InnoDB'
     tables incorrectly ignored rows where the length of the actual
     value was greater than the length of the index prefix.  (Bug
     #19960)

   * `make install' tried to build files that should already have been
     built by `make all', causing a failure if installation was
     performed using a different account than the one used for the
     initial build.  (Bug #19738)

   * For a `MyISAM' table with a `FULLTEXT' index, compression with
     *Note `myisampack': myisampack. or a check with *Note `myisamchk':
     myisamchk. after compression resulted in table corruption.  (Bug
     #19702)

   * The build process incorrectly tried to overwrite `sql/lex_hash.h'.
     This caused the build to fail when using a shadow link tree
     pointing to original sources that were owned by another account.
     (Bug #18888)

   * Linking the `pthreads' library to single-threaded MySQL libraries
     caused `dlopen()' to fail at runtime on HP-UX.  (Bug #18267)

   * The source distribution failed to compile when configured with the
     `--with-libwrap' option.  (Bug #18246)

   * Queries containing a subquery that used aggregate functions could
     return incorrect results.  (Bug #16792)

   * Row equalities (such as `WHERE (a,b) = (c,d)' were not taken into
     account by the optimizer, resulting in slow query execution. Now
     they are treated as conjunctions of equalities between row
     elements.  (Bug #16081)

   * `BIN()', `OCT()', and `CONV()' did not work with BIT values.  (Bug
     #15583)

   * The parser rejected queries that selected from a table twice using
     a *Note `UNION': union. within a subquery.  The parser now
     supports arbitrary subquery, join, and parenthesis operations
     within `EXISTS' subqueries. A limitation still exists for scalar
     subqueries: If the subquery contains *Note `UNION': union, the
     first *Note `SELECT': select. of the *Note `UNION': union. cannot
     be within parentheses. For example, `SELECT (SELECT a FROM t1
     UNION SELECT b FROM t2)' will work, but `SELECT ((SELECT a FROM
     t1) UNION (SELECT b FROM t2))' will not.  (Bug #14654)

   * On Mac OS X, zero-byte `read()' or `write()' calls to an
     SMB-mounted file system could return a nonstandard return value,
     leading to data corruption. Now such calls are avoided.  (Bug
     #12620)

   * The server returns a more informative error message when it
     attempts to open a `MERGE' table that has been defined to use
     non-`MyISAM' tables.  (Bug #10974)

   * With `TRADITIONAL' SQL mode, assignment of out-of-bound values and
     rounding of assigned values was done correctly, but assignment of
     the same numbers represented as strings sometimes was handled
     differently.  (Bug #6147)

   * On an *Note `INSERT': insert. into an updatable but noninsertable
     view, an error message was issued stating that the view was not
     updatable. Now the message says the view is not insertable-into.
     (Bug #5505)

   * *Note `EXPLAIN': explain. sometimes returned an incorrect
     `select_type' for a *Note `SELECT': select. from a view, compared
     to the `select_type' for the equivalent *Note `SELECT': select.
     from the base table.  (Bug #5500)

   * Incorporated portability fixes into the definition of
     `__attribute__' in `my_global.h'.  (Bug #2717)


File: manual.info,  Node: news-5-0-25,  Next: news-5-0-24a,  Prev: news-5-0-26,  Up: news-5-0-x

D.1.70 Changes in MySQL 5.0.25 (15 September 2006)
--------------------------------------------------

This is a bugfix release for the current production release family.
This version was released as MySQL Classic 5.0.25 to commercial
customers only.

This section documents all changes and bug fixes that have been applied
since the last official MySQL release. If you would like to receive
more fine-grained and personalized _update alerts_ about fixes that are
relevant to the version and features you use, please consider
subscribing to _MySQL Enterprise_ (a commercial MySQL offering). For
more details, please see http://www.mysql.com/products/enterprise.

*Functionality Added or Changed*

   * MySQL did not properly do stack dumps on `x86_64' and `i386/NPTL'
     systems. (Note that the initial fix for this problem was
     discovered not to be correct. Further work on the problem was
     undertaken only for MySQL 5.1 and up. See Bug #31891.)  (Bug
     #21250)

   * The *Note `mysqld': mysqld. and `mysqlmanager' man pages have been
     reclassified from volume 1 to volume 8.  (Bug #21220)

   * `InnoDB' now honors `IGNORE INDEX'. Previously using `IGNORE
     INDEX' in cases where an index sort would be slower than a
     filesort had no effect when used with `InnoDB' tables.

     *Note*:

     This fix was reverted in MySQL 5.0.26, and a new fix made in MySQL
     5.0.40.

     (Bug #21174)

   * *Note `TIMESTAMP': datetime. columns that are `NOT NULL' now are
     reported that way by *Note `SHOW COLUMNS': show-columns. and
     `INFORMATION_SCHEMA'.  (Bug #20910)

   * The MySQL distribution now compiles on UnixWare 7.13.  (Bug #20190)

   * `configure' now defines the symbol `DBUG_ON' in `config.h' to
     indicate whether the source tree is configured to be compiled with
     debugging support.  (Bug #19517)

   * *Note `mysql_upgrade': mysql-upgrade. no longer reads the
     `[client]' option file group because it is not a client and did
     not understand client options such as `host'. Now it reads only the
     `[mysql_upgrade]' group.  (Bug #19452)

   * For *Note `mysqlshow': mysqlshow, if a database name argument
     contains wildcard characters (such as ``_'') but matches a single
     database name exactly, treat the name as a literal name. This
     enables a command such as *Note `mysqlshow information_schema':
     mysqlshow. to work without having to escape the wildcard character.
     (Bug #19147)

   * On Windows, typing `Control+C' while a query was running caused
     the *Note `mysql': mysql. client to crash. Now it causes *Note
     `mysql': mysql. to attempt to kill the current statement. If this
     cannot be done, or `Control+C' is typed again before the statement
     is killed, *Note `mysql': mysql. exits. (In other words, *Note
     `mysql': mysql.'s behavior with regard to `Control+C' is now the
     same as it is on Unix platforms.)  (Bug #17926) See also Bug #1989.

   * The `VIEW_DEFINITION' column of the `INFORMATION_SCHEMA' *Note
     `VIEWS': views-table. table now contains information about the
     view algorithm.  (Bug #16832)

   * The bundled yaSSL library licensing has added a FLOSS exception
     similar to MySQL to resolve licensing incompatibilities with
     MySQL. (See the `extra/yassl/FLOSS-EXCEPTIONS' file in a MySQL
     source distribution for details.)  (Bug #16755)

   * Table comments longer than 60 characters and column comments
     longer than 255 characters were truncated silently. Now a warning
     is issued, or an error in strict mode.  (Bug #13934)

   * The *Note `mysql': mysql. client used the default character set if
     it automatically reconnected to the server, which is incorrect if
     the character set had been changed. To enable the character set to
     remain synchronized on the client and server, the *Note `mysql':
     mysql. command `charset' (or `\C') that changes the default
     character set and now also issues a `SET NAMES' statement. The
     changed character set is used for reconnects.  (Bug #11972)

   * If a *Note `DROP VIEW': drop-view. statement named multiple views,
     it stopped with an error if a nonexistent view was named and did
     not drop the remaining views. Now it continues on and reports an
     error at the end, similar to *Note `DROP TABLE': drop-table.  (Bug
     #11551)

   * The server now issues a warning if it removes leading spaces from
     an alias.  (Bug #10977)

   * For a successful dump, *Note `mysqldump': mysqldump. now writes a
     SQL comment to the end of the dump file in the following format:

          -- Dump completed on YYYY-MM-DD hh:mm:ss

     (Bug #10877)

   * For spatial data types, the server formerly returned these as
     `VARSTRING' values with a binary collation. Now the server returns
     spatial values as *Note `BLOB': blob. values.  (Bug #10166)

   * A new system variable, `lc_time_names', specifies the locale that
     controls the language used to display day and month names and
     abbreviations. This variable affects the output from the
     `DATE_FORMAT()', `DAYNAME()' and `MONTHNAME()' functions. See
     *Note locale-support::.

   * Using `--with-debug' to configure MySQL with debugging support
     enables you to use the `--debug="d,parser_debug"' option when you
     start the server. This causes the Bison parser that is used to
     process SQL statements to dump a parser trace to the server's
     standard error output. Typically, this output is written to the
     error log.

   * The bundled yaSSL library was upgraded to version 1.3.7.

*Bugs Fixed*

   * *Security Fix*: A stored routine created by one user and then made
     accessible to a different user using *Note `GRANT EXECUTE': grant.
     could be executed by that user with the privileges of the
     routine's definer.  (Bug #18630, CVE-2006-4227)

   * *Security Fix*: On Linux, and possibly other platforms using
     case-sensitive file systems, it was possible for a user granted
     rights on a database to create or access a database whose name
     differed only from that of the first by the case of one or more
     letters.  (Bug #17647, CVE-2006-4226)

   * *MySQL Cluster*: *Packaging*: The *Note `ndb_mgm':
     mysql-cluster-programs-ndb-mgm. program was included in both the
     `MySQL-ndb-tools' and `MySQL-ndb-management' RPM packages,
     resulting in a conflict if both were installed. Now *Note
     `ndb_mgm': mysql-cluster-programs-ndb-mgm. is included only in
     `MySQL-ndb-tools'.  (Bug #21058)

   * *MySQL Cluster*: Setting `TransactionDeadlockDetectionTimeout' to
     a value greater than 12000 would cause scans to deadlock, time
     out, fail to release scan records, until the cluster ran out of
     scan records and stopped processing.  (Bug #21800)

   * *MySQL Cluster*: A memory leak occurred when running *Note
     `ndb_mgm -e "SHOW"': mysql-cluster-programs-ndb-mgm.  (Bug #21670)

   * *MySQL Cluster*: The server provided a nondescriptive error
     message when encountering a fatally corrupted REDO log.  (Bug
     #21615)

   * *MySQL Cluster*: A partial rollback could lead to node restart
     failures.  (Bug #21536)

   * *MySQL Cluster*: The failure of a unique index read due to an
     invalid schema version could be handled incorrectly in some cases,
     leading to unpredictable results.  (Bug #21384)

   * *MySQL Cluster*: In a cluster with more than 2 replicas, a manual
     restart of one of the data nodes could fail and cause the other
     nodes in the same node group to shut down.  (Bug #21213)

   * *MySQL Cluster*: Some queries involving joins on very large *Note
     `NDB': mysql-cluster. tables could crash the MySQL server.  (Bug
     #21059)

   * *MySQL Cluster*: Restarting a data node while DDL operations were
     in progress on the cluster could cause other data nodes to fail.
     This could also lead to *Note `mysqld': mysqld. hanging or
     crashing under some circumstances.  (Bug #21017, Bug #21050)

   * *MySQL Cluster*: In some situations with a high disk-load, writing
     of the redo log could hang, causing a crash with the error message
     `GCP STOP detected'.  (Bug #20904)

   * *MySQL Cluster*: When the redo buffer ran out of space, a `Pointer
     too large' error was raised and the cluster could become unusable
     until restarted with `--initial'.  (Bug #20892)

   * *MySQL Cluster*: A vague error message was returned when reading
     both schema files during a restart of the cluster.  (Bug #20860)

   * *MySQL Cluster*: Incorrect values were inserted into
     `AUTO_INCREMENT' columns of tables restored from a cluster backup.
     (Bug #20820)

   * *MySQL Cluster*: When attempting to restart the cluster following
     a data import, the cluster failed during Phase 4 of the restart
     with `Error 2334: Job buffer congestion'.  (Bug #20774)

   * *MySQL Cluster*: *Note `REPLACE': replace. statements did not work
     correctly on an *Note `NDB': mysql-cluster. table having both a
     primary key and a unique key. In such cases, proper values were
     not set for columns which were not explicitly referenced in the
     statement.  (Bug #20728)

   * *MySQL Cluster*: The server did not honor the value set for
     `ndb_cache_check_time' in the `my.cnf' file.  (Bug #20708)

   * *MySQL Cluster*: *Note `ndb_size.pl':
     mysql-cluster-programs-ndb-size-pl. and *Note
     `ndb_error_reporter': mysql-cluster-programs-ndb-error-reporter.
     were missing from RPM packages.  (Bug #20426)

   * *MySQL Cluster*: Running *Note `ndbd': mysql-cluster-programs-ndbd.
     `--nowait-nodes=ID ' where ID was the node ID of a node that was
     already running would fail with an invalid error message.  (Bug
     #20419)

   * *MySQL Cluster*: A node failure during a scan could sometime cause
     the node to crash when restarting too quickly following the
     failure.  (Bug #20197)

   * *MySQL Cluster*: It was possible to use port numbers greater than
     65535 for `ServerPort' in the `config.ini' file.  (Bug #19164)

   * *MySQL Cluster*: Under certain circumstances, a node that was shut
     down then restarted could hang during the restart.  (Bug #18863)

   * *MySQL Cluster*: Trying to create or drop a table while a node was
     restarting caused the node to crash. This is now handled by
     raising an error.  (Bug #18781)

   * *MySQL Cluster*: The server failed with a nondescriptive error
     message when out of data memory.  (Bug #18475)

   * *MySQL Cluster*: For *Note `NDB': mysql-cluster. and possibly
     `InnoDB' tables, a `BEFORE UPDATE' trigger could insert incorrect
     values.  (Bug #18437)

   * *MySQL Cluster*: *Note `SELECT ... FOR UPDATE': select. failed to
     lock the selected rows.  (Bug #18184)

   * *MySQL Cluster*: *Note `perror': perror. did not properly report
     *Note `NDB': mysql-cluster. error codes.  (Bug #16561)

   * *MySQL Cluster*: A Cluster whose storage nodes were installed from
     the `MySQL-ndb-storage-* ' RPMs could not perform `CREATE' or
     `ALTER' operations that made use of nondefault character sets or
     collations.  (Bug #14918)

   * *MySQL Cluster*: The management client `ALL STATUS' command could
     sometimes report the status of some data nodes incorrectly.  (Bug
     #13985)

   * *MySQL Cluster*: An issue that arose from a patch for Bug #19852
     made in MySQL 5.0.23 was corrected. (See *Note news-5-0-23::.)

   * *Cluster Replication*: *Replication*: In some cases, a large
     number of MySQL servers sending requests to the cluster
     simultaneously could cause the cluster to crash.  This could also
     be triggered by many *Note `NDB': mysql-cluster. API clients
     making simultaneous event subscriptions or unsubscriptions.  (Bug
     #20683)

   * *Replication*: *Note `CREATE PROCEDURE': create-procedure, *Note
     `CREATE FUNCTION': create-function, *Note `CREATE TRIGGER':
     create-trigger, and *Note `CREATE VIEW': create-view. statements
     containing multi-line comments (`/* ... */') could not be
     replicated.  (Bug #20438)

   * *Cluster API*: Invoking the MGM API function
     `ndb_mgm_listen_event()'
     (http://dev.mysql.com/doc/ndbapi/en/mgm-ndb-mgm-listen-event.html)
     caused a memory leak.  (Bug #21671)

   * *Cluster API*: The MGM API function `ndb_logevent_get_fd()' was
     not implemented.  (Bug #21129)

   * *Cluster API*: `NdbScanOperation::readTuples()' and
     `NdbIndexScanOperation::readTuples()' ignored the BATCH parameter.
     (Bug #20252)

   * Some Linux-x86_64-icc packages (of previous releases) mistakenly
     contained 32-bit binaries. Only `ICC' builds are affected, not
     `gcc' builds. Solaris and FreeBSD x86_64 builds are not affected.
     (Bug #22238)

   * Running *Note `SHOW MASTER LOGS': show-binary-logs. at the same
     time as binary log files were being switched would cause `mysqld'
     to hang.  (Bug #21965)

   * `libmysqlclient' defined a symbol `BN_bin2bn' which belongs to
     OpenSSL. This could break applications that also linked against
     OpenSSL's `libcrypto' library. The fix required correcting an
     error in a build script that was failing to add rename macros for
     some functions.  (Bug #21930)

   * `character_set_results' can be `NULL' to signify `no conversion,'
     but some code did not check for `NULL', resulting in a server
     crash.  (Bug #21913)

   * A `NUL' byte within a prepared statement string caused the rest of
     the string not to be written to the query log, permitting logging
     to be bypassed.  (Bug #21813)

   * `COUNT(*)' queries with `ORDER BY' and `LIMIT' could return the
     wrong result.

     *Note*:

     This problem was introduced by the fix for Bug #9676, which
     limited the rows stored in a temporary table to the `LIMIT'
     clause. This optimization is not applicable to nongroup queries
     with aggregate functions. The current fix disables the
     optimization in such cases.

     (Bug #21787)

   * *Note `INSERT ... SELECT': insert-select. sometimes generated a
     spurious `Column count doesn't match value count' error.  (Bug
     #21774)

   * `EXPORT_SET()' did not accept arguments with coercible character
     sets.  (Bug #21531)

   * *Note `mysqldump': mysqldump. incorrectly tried to use *Note `LOCK
     TABLES': lock-tables. for tables in the `INFORMATION_SCHEMA'
     database.  (Bug #21527)

   * Memory overruns could occur for certain kinds of subqueries.  (Bug
     #21477)

   * A *Note `DATE': datetime. can be represented as an integer (such
     as `20060101') or as a string (such as `'2006.01.01''). When a
     *Note `DATE': datetime. (or *Note `TIME': time.) column is
     compared in one *Note `SELECT': select. against both
     representations, constant propagation by the optimizer led to
     comparison of *Note `DATE': datetime. as a string against *Note
     `DATE': datetime. as an integer. This could result in integer
     comparisons such as `2006' against `20060101', erroneously
     producing a false result.  (Bug #21475)

   * Adding `ORDER BY' to a `SELECT DISTINCT(EXPR)' query could produce
     incorrect results.  (Bug #21456)

   * Database and table names have a maximum length of 64 characters
     (even if they contain multi-byte characters), but were truncated
     to 64 bytes.

     *Note*:

     This fix was reverted in MySQL 5.0.26.

     (Bug #21432)

   * With `max_sp_recursion' set to 0, a stored procedure that executed
     a *Note `SHOW CREATE PROCEDURE': show-create-procedure. statement
     for itself triggered a recursion limit exceeded error, though the
     statement involves no recursion.  (Bug #21416)

   * On 64-bit Windows, a missing table generated error 1017, not the
     correct value of 1146.  (Bug #21396)

   * The optimizer sometimes produced an incorrect row-count estimate
     after elimination of `const' tables. This resulted in choosing
     extremely inefficient execution plans in same cases when
     distribution of data in joins were skewed.  (Bug #21390)

   * A query result could be sorted improperly when using `ORDER BY'
     for the second table in a join.  (Bug #21302)

   * Query results could be incorrect if the `WHERE' clause contained
     `t.KEY_PART NOT IN (VAL_LIST)', where VAL_LIST is a list of more
     than 1000 constants.  (Bug #21282)

   * For user-defined functions created with *Note `CREATE FUNCTION':
     create-function, the `DEFINER' clause is not legal, but no error
     was generated.  (Bug #21269)

   * The `SELECT' privilege was required for an insert on a view,
     instead of the `INSERT' privilege.  (Bug #21261) This regression
     was introduced by Bug #20989.

   * Subqueries on `INFORMATION_SCHEMA' tables could erroneously return
     an empty result.  (Bug #21231)

   * *Note `mysql_upgrade': mysql-upgrade. created temporary files in a
     possibly insecure way.  (Bug #21224)

   * When *Note `DROP DATABASE': drop-database. or *Note `SHOW OPEN
     TABLES': show-open-tables. was issued while concurrently in
     another connection issuing *Note `DROP TABLE': drop-table, *Note
     `RENAME TABLE': rename-table, `CREATE TABLE LIKE' or any other
     statement that required a name lock, the server crashed.  (Bug
     #21216, Bug #19403)

   * The `--master-data' option for *Note `mysqldump': mysqldump.
     requires certain privileges, but *Note `mysqldump': mysqldump.
     generated a truncated dump file without producing an appropriate
     error message or exit status if the invoking user did not have
     those privileges.  (Bug #21215)

   * Some prepared statements caused a server crash when executed a
     second time.  (Bug #21166)

   * The optimizer assumed that if `(a=x AND b=x)' is true, `(a=x AND
     b=x) AND a=b' is also true.  But that is not always so if `a' and
     `b' have different data types.  (Bug #21159)

   * *Note `SHOW INNODB STATUS': show-innodb-status. contained some
     duplicate output.  (Bug #21113)

   * `InnoDB' was slow with more than 100,000 `.idb' files.  (Bug
     #21112)

   * Performing an *Note `INSERT': insert. on a view that was defined
     using a *Note `SELECT': select.  that specified a collation and a
     column alias caused the server to crash .  (Bug #21086)

   * *Note `ALTER VIEW': alter-view. did not retain existing values of
     attributes that had been originally specified but were not changed
     in the *Note `ALTER VIEW': alter-view. statement.  (Bug #21080)

   * For `InnoDB' tables, the server could crash when executing `NOT
     IN(...)' subqueries.  (Bug #21077)

   * The `myisam_stats_method' variable was mishandled when set from an
     option file or on the command line.  (Bug #21054)

   * With `query_cache_type' set to 0, `RESET QUERY CACHE' was very
     slow and other threads were blocked during the operation. Now a
     cache reset is faster and nonblocking.  (Bug #21051)

   * *Note `mysql': mysql. crashed for very long arguments to the
     `connect' command.  (Bug #21042)

   * A query using `WHERE COLUMN = CONSTANT OR COLUMN IS NULL' did not
     return consistent results on successive invocations. The COLUMN in
     each part of the `WHERE' clause could be either the same column,
     or two different columns, for the effect to be observed.  (Bug
     #21019)

   * Performance during an import on a table with a trigger that called
     a stored procedure was severely degraded. This issue first arose
     in MySQL 5.0.18.  (Bug #21013)

   * A query of the form shown here caused the server to crash:

          SELECT * FROM t1 NATURAL JOIN (
              t2 JOIN (
                  t3 NATURAL JOIN t4,
                  t5 NATURAL JOIN t6
              )
              ON (t3.id3 = t2.id3 AND t5.id5 = t2.id5)
          );

     (Bug #21007)

   * `STR_TO_DATE()' sometimes would return `NULL' if the `%D' format
     specifier was not the last specifier in the format string.  (Bug
     #20987)

   * A query using `WHERE NOT (COLUMN < ANY (SUBQUERY))' yielded a
     different result from the same query using the same COLUMN and
     SUBQUERY with `WHERE (COLUMN > ANY (SUBQUERY))'.  (Bug #20975)

   * In debugging mode, *Note `mysqld': mysqld. printed `server_init'
     rather than `network_init' during network initialization.  (Bug
     #20968)

   * Under certain circumstances, `AVG(KEY_VAL)' returned a value but
     `MAX(KEY_VAL)' returned an empty set due to incorrect application
     of `MIN()/MAX()' optimization.  (Bug #20954)

   * On Windows, *Note `mysql_upgrade.exe': mysql-upgrade. could not
     find *Note `mysqlcheck.exe': mysqlcheck.  (Bug #20950)

   * Use of zero-length variable names caused a server crash.  (Bug
     #20908)

   * The server crashed when using the range access method to execut a
     subquery with a `ORDER BY DESC' clause.  (Bug #20869)

   * For certain queries, the server incorrectly resolved a reference
     to an aggregate function and crashed.  (Bug #20868)

   * Using aggregate functions in subqueries yielded incorrect results
     under certain circumstances due to incorrect application of
     `MIN()'/`MAX()' optimization.  (Bug #20792)

   * If a column definition contained a character set declaration, but
     a `DEFAULT' value began with an introducer, the introducer
     character set was used as the column character set.  (Bug #20695)

   * Multiplication of *Note `DECIMAL': numeric-types. values could
     produce incorrect fractional part and trailing garbage caused by
     signed overflow.  (Bug #20569)

   * Users who had the `SHOW VIEW' privilege for a view and privileges
     on one of the view's base tables could not see records in
     `INFORMATION_SCHEMA' tables relating to the base table.  (Bug
     #20543)

   * The `MD5()', `SHA1()', and `ENCRYPT()' functions should return a
     binary string, but the result sometimes was converted to the
     character set of the argument.  `MAKE_SET()' and `EXPORT_SET()'
     now use the correct character set for their default separators,
     resulting in consistent result strings which can be coerced
     according to normal character set rules.  (Bug #20536)

   * A subquery that contained `LIMIT N,1' could return more than one
     row.  (Bug #20519)

   * Creation of a view as a join of views or tables could fail if the
     views or tables are in different databases.  (Bug #20482)

   * *Note `SELECT': select. statements using `GROUP BY' against a view
     could have missing columns in the output when there was a trigger
     defined on one of the base tables for the view.  (Bug #20466)

   * For connections that required a `SUBJECT' value, a check was
     performed to verify that the value was correct, but the connection
     was not refused if not.  (Bug #20411)

   * Some user-level errors were being written to the server's error
     log, which is for server errors.  (Bug #20402)

   * *Note `perror': perror. crashed on Solaris due to `NULL' return
     value of `strerror()' system call.  (Bug #20145)

   * For *Note `mysql': mysql, escaping with backslash sometimes did
     not work.  (Bug #20103)

   * Use of `MIN()' or `MAX()' with `GROUP BY' on a `ucs2' column could
     cause a server crash.  (Bug #20076)

   * *Note `mysqld --flush': mysqld. failed to flush `MyISAM' table
     changes to disk following an *Note `UPDATE': update. statement for
     which no updated column had an index.  (Bug #20060)

   * A user-defined function that is called on each row of a returned
     result set, could receive an `in_null' state that is set, if it
     was set previously. Now, the `is_null' state is reset to false
     before each invocation of a UDF.  (Bug #19904)

   * The `query' command for `mysqltest' did not work.  (Bug #19890)

   * When executing a *Note `SELECT': select. with `ORDER BY' on a view
     that is constructed from a *Note `SELECT': select. statement
     containing a stored function, the stored function was evaluated
     too many times.  (Bug #19862)

   * The first time a user who had been granted the `CREATE ROUTINE'
     privilege used that privilege to create a stored procedure or
     function, the `Password' column in that user's row in the
     `mysql.user' table was set to `NULL'.  (Bug #19857)

   * For `TIME_FORMAT()', the `%H' and `%k' format specifiers can
     return values larger than two digits (if the hour is greater than
     99), but for some query results that contained three-character
     hours, column values were truncated.  (Bug #19844)

   * Using *Note `SELECT': select. on a corrupt `MyISAM' table using
     the dynamic record format could cause a server crash.  (Bug #19835)

   * Using cursors with `READ COMMITTED' isolation level could cause
     `InnoDB' to crash.  (Bug #19834)

   * The yaSSL library bundled with `libmysqlclient' had some conflicts
     with OpenSSL. Now macros are used to rename the conflicting
     symbols to have a prefix of `ya'.  (Bug #19810)

   * On 64-bit systems, use of the `cp1250' character set with a
     primary key column in a `LIKE' clause caused a server crash for
     patterns having letters in the range 128..255.  (Bug #19741)

   * *Note `DESCRIBE': describe. returned the type *Note `BIGINT':
     numeric-types. for a column of a view if the column was specified
     by an expression over values of the type *Note `INT':
     numeric-types.  (Bug #19714)

   * An issue with yaSSL prevented Connector/J clients from connecting
     to the server using a certificate.  (Bug #19705)

   * A cast problem caused incorrect results for prepared statements
     that returned float values when MySQL was compiled with `gcc' 4.0.
     (Bug #19694)

   * The *Note `mysql_list_fields()': mysql-list-fields. C API function
     returned the incorrect table name for views.  (Bug #19671)

   * If a query had a condition of the form ` TABLEX.KEY = TABLEY.KEY
     ', which participated in equality propagation and also was used
     for `ref' access, then early `ref'-access `NULL' filtering was not
     performed for the condition. This could make query execution
     slower.  (Bug #19649)

   * Repeated *Note `DROP TABLE': drop-table. statements in a stored
     procedure could sometimes cause the server to crash.  (Bug #19399)

   * When not running in strict mode, the server failed to convert the
     invalid years portion of a *Note `DATE': datetime. or *Note
     `DATETIME': datetime. value to `'0000'' when inserting it into a
     table.

     *Note*:

     This fix was reverted in MySQL 5.0.40.

     (Bug #19370) See also Bug #25301.

   * The final parenthesis of a *Note `CREATE INDEX': create-index.
     statement occurring in a stored procedure was omitted from the
     binary log when the stored procedure was called.  (Bug #19207)

   * A *Note `SELECT': select. with a subquery that was bound to the
     outer query over multiple columns returned different results when
     a constant was used instead of one of the dependant columns.  (Bug
     #18925)

   * Setting `myisam_repair_threads' caused any repair operation on a
     `MyISAM' table to fail to update the cardinality of indexes,
     instead making them always equal to 1.  (Bug #18874)

   * `FEDERATED' tables raised invalid duplicate key errors when
     attempting on one server to insert rows having the same primary
     key values as rows that had been deleted from the linked table on
     the other server.  (Bug #18764)

   * The implementation for `UNCOMPRESS()' did not indicate that it
     could return `NULL', causing the optimizer to do the wrong thing.
     (Bug #18539)

   * Using `> ALL' with subqueries that return no rows yielded
     incorrect results under certain circumstances due to incorrect
     application of `MIN()'/`MAX()' optimization.  (Bug #18503)

   * Referring to a stored function qualified with the name of one
     database and tables in another database caused a `table doesn't
     exist' error.  (Bug #18444)

   * Triggers on tables in the `mysql' database caused a server crash.
     Triggers for tables in this database are no longer permitted.
     (Bug #18361, Bug #18005)

   * The length of the pattern string prefix for `LIKE' operations was
     calculated incorrectly for multi-byte character sets. As a result,
     the scanned range was wider than necessary if the prefix contained
     any multi-byte characters, and rows could be missing from the
     result set.  (Bug #18359, Bug #16674)

   * Multiple invocations of the `REVERSE()' function could return
     different results.  (Bug #18243)

   * The optimizer did not take advantage of indexes on columns used
     for the second or third arguments of `BETWEEN'.  (Bug #18165)

   * For table-format output, *Note `mysql': mysql. did not always
     calculate columns widths correctly for columns containing
     multi-byte characters in the column name or contents.  (Bug #17939)

   * The character set was not being properly initialized for `CAST()'
     with a type such as *Note `CHAR(2) BINARY': char, which resulted in
     incorrect results or a server crash.  (Bug #17903)

   * Checking a `MyISAM' table (using *Note `CHECK TABLE':
     check-table.) having a spatial index and only one row would
     wrongly indicate that the table was corrupted.  (Bug #17877)

   * A stored procedure that created and invoked a prepared statement
     was not executed when called in a mysqld init-file.  (Bug #17843)

   * It is possible to create `MERGE' tables into which data cannot be
     inserted (by not specifying a *Note `UNION': union. clause.
     However, when an insert was attempted, the error message was
     confusing. Now an error occurs indicating that the table is read
     only.  (Bug #17766)

   * Attempting to insert a string of greater than 4096 bytes into a
     `FEDERATED' table resulted in the error `ERROR 1296 (HY000) at
     line 2: Got error 10000 'Error on remote system: 1054: Unknown
     column 'STRING-VALUE' from FEDERATED'. This error was raised
     regardless of the type of column involved (*Note `VARCHAR': char,
     *Note `TEXT': blob, and so on.)  (Bug #17608)

   * Views could not be updated within a stored function or trigger.
     (Bug #17591)

   * Use of the `--prompt' option or `prompt' command caused *Note
     `mysql': mysql. to be unable to connect to the Instance Manager.
     (Bug #17485)

   * `N'xxx'' and `_utf8'xxx'' were not treated as equivalent because
     `N'xxx'' failed to unescape backslashes (`\') and doubled
     apostrophe/single quote characters (`''').  (Bug #17313)

   * Use of the join cache in favor of an index for `ORDER BY'
     operations could cause incorrect result sorting.  (Bug #17212)

   * The `PASSWORD()' function returned invalid results when used in
     some *Note `UNION': union. queries.  (Bug #16881)

   * `ORDER BY RAND() LIMIT 1' always set a user variable to the last
     possible value from the table.  (Bug #16861)

   * When performing a `GROUP_CONCAT()', the server transformed *Note
     `BLOB': blob.  columns *Note `VARCHAR': char. columns, which could
     cause erroneous results when using Connector/J and possibly other
     MySQL APIs.  (Bug #16712)

   * Stored procedures did not use the character set defined for the
     database in which they were created.  (Bug #16676)

   * Some server errors were not reported to the client, causing both
     to try to read from the connection until a hang or crash resulted.
     (Bug #16581)

   * On Windows, a definition for *Note `mysql_set_server_option()':
     mysql-set-server-option. was missing from the C client library.
     (Bug #16513)

   * Updating a column of a `FEDERATED' table to `NULL' sometimes
     failed.  (Bug #16494)

   * For *Note `SELECT ... FOR UPDATE': select. statements that used
     `DISTINCT' or `GROUP BY' over all key parts of a unique index (or
     primary key), the optimizer unnecessarily created a temporary
     table, thus losing the linkage to the underlying unique index
     values. This caused a `Result set not updatable' error. (The
     temporary table is unnecessary because under these circumstances
     the distinct or grouped columns must also be unique.)  (Bug #16458)

   * Using `ANY' with `nontable' subqueries such as `SELECT 1' yielded
     incorrect results under certain circumstances due to incorrect
     application of `MIN()'/`MAX()' optimization.  (Bug #16302)

   * A subquery in the `WHERE' clause of the outer query and using `IN'
     and `GROUP BY' returned an incorrect result.  (Bug #16255)

   * A query could produce different results with and without and
     index, if the `WHERE' clause contained a range condition that used
     an invalid *Note `DATETIME': datetime. constant.  (Bug #16249)

   * `TIMESTAMPDIFF()' examined only the date and ignored the time when
     the requested difference unit was months or quarters.  (Bug #16226)

   * Using tables from MySQL 4.x in MySQL 5.x, in particular those with
     *Note `VARCHAR': char. fields and using *Note `INSERT DELAYED':
     insert-delayed. to update data in the table would result in either
     data corruption or a server crash.  (Bug #16218, Bug #17294, Bug
     #16611)

   * The value returned by a stored function returning a string value
     was not of the declared character set.  (Bug #16211)

   * The `index_merge'/`Intersection' optimizer could experience a
     memory overrun when the number of table columns covered by an
     index was sufficiently large, possibly resulting in a server crash.
     (Bug #16201)

   * *Note `DECIMAL': numeric-types. columns were handled incorrectly
     in two respects :

       1. When the precision of the column was too small for the value.
          In this case, the original value was returned instead of an
          error.

       2. When the scale of the column was set to 0. In this case, the
          value. In this case, the value was treated as though the
          scale had been defined as 2.

     (Bug #16172)

   * Certain queries having a `WHERE' clause that included conditions
     on multi-part keys with more than 2 key parts could produce
     incorrect results and send `[Note] Use_count: Wrong count for key
     at...' messages to `STDERR'.  (Bug #16168)

   * When a row was inserted through a view but did not specify a value
     for a column that had no default value in the base table, no
     warning or error occurred. Now a warning occurs, or an error in
     strict SQL mode.  (Bug #16110)

   * When `NOW()' was used in a `BETWEEN' clause of the definition for
     a view, it was replaced with a constant in the view.  (Bug #15950)

   * The C API failed to return a status message when invoking a stored
     procedure.  (Bug #15752)

   * *Note `mysqlimport': mysqlimport. sends a `set
     @@character_set_database=binary' statement to the server, but this
     is not understood by pre-4.1 servers. Now *Note `mysqlimport':
     mysqlimport. encloses the statement within a `/*!40101 ... */'
     comment so that old servers will ignore it.  (Bug #15690)

   * For the `CSV' storage engine, memory-mapped pages of the data file
     were not invalidated when new data was appended to the file using
     traditional (file descriptor-based) I/O primitives.  (Bug #15669)

   * `SHOW GRANTS FOR CURRENT_USER' did not return definer grants when
     executed in `DEFINER' context (such as within a stored prodedure
     defined with `SQL SECURITY DEFINER'), it returned the invoker
     grants.  (Bug #15298)

   * The `--collation-server' server option was being ignored. With the
     fix, if you choose a nondefault character set with
     `--character-set-server', you should also use `--collation-server'
     to specify the collation.  (Bug #15276)

   * The server crashed if it tried to access a `CSV' table for which
     the data file had been removed.  (Bug #15205)

   * Tables created with the `FEDERATED' storage engine did not permit
     indexes using `NULL' columns.  (Bug #15133)

   * When using tables containing *Note `VARCHAR': char. columns
     created under MySQL 4.1 with a 5.0 or later server, for some
     queries the metadata sent to the client could have an empty column
     name.  (Bug #14897)

   * *Note `CREATE TABLE ... SELECT': create-table. statements that
     selected `GEOMETRY' values resulted in a table that contained
     *Note `BLOB': blob. columns, not `GEOMETRY' columns.  (Bug #14807)

   * When setting a column to its implicit default value as the result
     of inserting a `NULL' into a `NOT NULL' column as part of a
     multi-row insert or *Note `LOAD DATA': load-data. operation, the
     server returned a misleading warning message.  (Bug #14770)

   * The use of `WHERE COL_NAME IS NULL' in *Note `SELECT': select.
     statements reset the value of `LAST_INSERT_ID()' to zero.  (Bug
     #14553)

   * Inserts into *Note `BIT': numeric-types. columns of `FEDERATED'
     tables did not work.  (Bug #14532)

   * Using *Note `SELECT': select. and a table join while running a
     concurrent *Note `INSERT': insert.  operation would join incorrect
     rows.  (Bug #14400)

   * Prepared statements caused general log and server memory
     corruption.  (Bug #14346)

   * `libmysqld' produced some warnings to `stderr' which could not be
     silenced. These warnings now are suppressed.  (Bug #13717)

   * The Instance Manager permitted `STOP INSTANCE' to be used on a
     server instance that was not running.  (Bug #12673)

   * For very complex *Note `SELECT': select.  statements could create
     temporary tables that were too large, and for which the temporary
     files were not removed, causing subsequent queries to fail.  (Bug
     #11824)

   * *Note `USE': use. did not refresh database privileges when
     employed to re-select the current database.  (Bug #10979)

   * The type of the value returned by the `VARIANCE()' function varied
     according to the type of the input value. The function should
     always return a *Note `DOUBLE': numeric-types. value.  (Bug #10966)

   * The same trigger error message was produced under two conditions:
     The trigger duplicated an existing trigger name, or the trigger
     duplicated an existing combination of action and event. Now
     different messages are produced for the two conditions so as to be
     more informative.  (Bug #10946)

   * *Note `CREATE USER': create-user. did not respect the 16-character
     user name limit.  (Bug #10668)

   * A server or network failure with an open client connection would
     cause the client to hang even though the server was no longer
     available.

     As a result of this change, the `MYSQL_OPT_READ_TIMEOUT' and
     `MYSQL_OPT_WRITE_TIMEOUT' options for *Note `mysql_options()':
     mysql-options. now apply to TCP/IP connections on all platforms.
     Previously, they applied only to Windows.  (Bug #9678)

   * `INSERT INTO ... SELECT ... LIMIT 1' could be slow because the
     `LIMIT' was ignored when selecting candidate rows.  (Bug #9676)

   * The optimizer could produce an incorrect result after `AND' with
     collations such as `latin1_german2_ci', `utf8_czech_ci', and
     `utf8_lithianian_ci'.  (Bug #9509)

   * A stored procedure with a `CONTINUE' handler that encountered an
     error continued to execute a statement that caused an error,
     rather with the next statement following the one that caused the
     error.  (Bug #8153)

   * For ODBC compatibility, MySQL supports use of `WHERE COL_NAME IS
     NULL' for *Note `DATE': datetime. or *Note `DATETIME': datetime.
     columns that are `NOT NULL', to permit column values of
     `'0000-00-00'' or `'0000-00-00 00:00:00'' to be selected. However,
     this was not working for `WHERE' clauses in *Note `DELETE':
     delete. statements.  (Bug #8143)

   * A user variable set to a value selected from an unsigned column
     was stored as a signed value.  (Bug #7498)

   * The `--with-collation' option was not honored for client
     connections.  (Bug #7192)


File: manual.info,  Node: news-5-0-24a,  Next: news-5-0-24,  Prev: news-5-0-25,  Up: news-5-0-x

D.1.71 Changes in MySQL 5.0.24a (25 August 2006)
------------------------------------------------

This is a bugfix release for the current production release family. It
replaces MySQL 5.0.24.

*Bugs Fixed*

   * The shared compatibility RPM files were missing some files.  (Bug
     #22251)

   * *Note `mysqld': mysqld. could crash when closing temporary tables.
     (Bug #21582)

   * MySQL 5.0.24 introduced an ABI incompatibility, which this release
     reverts. Programs compiled against 5.0.24 are not compatible with
     any other version and must be recompiled.  (Bug #21543)

   * Path name separator and device characters were not correctly
     parameterized for NetWare, causing *Note `mysqld': mysqld.
     startup errors.  (Bug #21537)

   * Closing of temporary tables failed if binary logging was not
     enabled.  (Bug #20919)

   * For statements that have a `DEFINER' clause such as *Note `CREATE
     TRIGGER': create-trigger. or *Note `CREATE VIEW': create-view,
     long user names or host names could cause a buffer overflow.  (Bug
     #16899)


File: manual.info,  Node: news-5-0-24,  Next: news-5-0-23,  Prev: news-5-0-24a,  Up: news-5-0-x

D.1.72 Changes in MySQL 5.0.24 (27 July 2006)
---------------------------------------------

This is a bugfix release for the current production release family.

This section documents all changes and bug fixes that have been applied
since the last official MySQL release. If you would like to receive
more fine-grained and personalized _update alerts_ about fixes that are
relevant to the version and features you use, please consider
subscribing to _MySQL Enterprise_ (a commercial MySQL offering). For
more details, please see http://www.mysql.com/products/enterprise.

*Functionality Added or Changed*

   * In the *Note `INFORMATION_SCHEMA.ROUTINES': routines-table.  table
     the `ROUTINE_DEFINITION' column now is defined as `NULL' rather
     than `NOT NULL'. Also, `NULL' rather than the empty string is
     returned as the column value if the user does not have sufficient
     privileges to see the routine definition.  (Bug #20230)

   * The `LEFT()' and `RIGHT()' functions return `NULL' if any argument
     is `NULL'.  (Bug #11728)

   * The `innodb_log_arch_dir' system variable (which has been unused
     since MySQL 4.0.6) is now deprecated and should no longer be used.
     It will be removed in MySQL 5.1.

   * Program Database files (extension `.pdb') are now included by
     default in Windows distributions. These can be used to help
     diagnose problems with *Note `mysqld': mysqld.  and other tools.
     See *Note debugging-server::.

*Bugs Fixed*

   * *Security Fix*: If a user has access to `MyISAM' table T, that
     user can create a `MERGE' table M that accesses T. However, if the
     user's privileges on T are subsequently revoked, the user can
     continue to access T by doing so through M. If this behavior is
     undesirable, you can start the server with the new `--skip-merge'
     option to disable the `MERGE' storage engine.  (Bug #15195,
     CVE-2006-4031)

   * *MySQL Cluster*: The *Note `ndb_size.pl':
     mysql-cluster-programs-ndb-size-pl. script did not account for
     *Note `TEXT': blob. and *Note `BLOB': blob. column values
     correctly.  (Bug #21204)

   * *MySQL Cluster*: The repeated creating and dropping of a table
     would eventually lead to *Note `NDB': mysql-cluster. Error 826,
     `Too many tables and attributes ... Insufficient space'.  (Bug
     #20847)

   * *Replication*: A race condition during slave server shutdown
     caused an assert failure.  (Bug #20850)

   * *Replication*: With the `auto_increment_increment' system variable
     set larger than 1, if the next generated `AUTO_INCREMENT' value
     would be larger than the column's maximum value, the value would
     be clipped down to that maximum value and inserted, even if the
     resulting value would not be in the generated sequence. This could
     cause problems for master-master replication. Now the server clips
     the value down to the previous value in the sequence, which
     correctly produces a duplicate-key error if that value already
     exists in the column.  (Bug #20524)

   * *Replication*: If a table on a slave server had a higher
     `AUTO_INCREMENT' counter than the corresponding master table (even
     though all rows of the two tables were identical), in some cases
     *Note `REPLACE': replace.  or *Note `INSERT ... ON DUPLICATE KEY
     UPDATE': insert-on-duplicate. would not replicate properly using
     statement-based logging. (Different values would be inserted on
     the master and slave.)  (Bug #20188)

   * Under heavy load (executing more than 1024 simultaneous complex
     queries), a problem in the code that handles internal temporary
     tables could lead to writing beyond allocated space and memory
     corruption.

     Use of more than 1024 simultaneous cursors server wide also could
     lead to memory corruption. This applies to both stored procedure
     cursors and C API cursors.  (Bug #21206)

   * Failure to account for a `NULL' table pointer on big-endian
     machines could cause a server crash during type conversion.  (Bug
     #21135)

   * *Note `mysqldump': mysqldump. sometimes did not select the correct
     database before trying to dump views from it, resulting in an
     empty result set that caused *Note `mysqldump': mysqldump.  to die
     with a segmentation fault.  (Bug #21014)

   * A *Note `SELECT': select. that used a subquery in the `FROM'
     clause that did not select from a table failed when the subquery
     was used in a join.  (Bug #21002)

   * *Note `REPLACE ... SELECT': replace. for a view required the
     `INSERT' privilege for tables other than the table being modified.
     (Bug #20989)

   * Issuing a *Note `SHOW CREATE FUNCTION': show-create-function. or
     *Note `SHOW CREATE PROCEDURE': show-create-procedure. statement
     without sufficient privileges could crash the *Note `mysql':
     mysql. client.  (Bug #20664)

   * In a view defined with `SQL SECURITY DEFINER', the
     `CURRENT_USER()' function returned the invoker, not the definer.
     (Bug #20570)

   * `SELECT @@INSERT_ID' displayed a value unrelated to a preceding
     `SET INSERT_ID'. (It returned `LAST_INSERT_ID' instead.)  (Bug
     #20392)

   * The *Note `mysql': mysql. client did not understand `help'
     commands that had spaces at the end.  (Bug #20328)

   * *Note `mysqldump': mysqldump. produced a malformed dump file when
     dumping multiple databases that contained views.  (Bug #20221)

   * For a *Note `DATE': datetime. parameter sent using a `MYSQL_TIME'
     data structure, *Note `mysql_stmt_execute()': mysql-stmt-execute.
     zeroed the hour, minute, and second members of the structure
     rather than treating them as read only.  (Bug #20152)

   * Performing `INSERT ... SELECT ... JOIN ...  USING' without
     qualifying the column names caused `ERROR 1052 "column 'x' in
     field list is ambiguous"' even in cases where the column references
     were unambiguous.  (Bug #18080)

   * Using the extended syntax for `TRIM()'--that is, `TRIM(... FROM
     ...)'--in a *Note `SELECT': select. statement defining a view
     caused an invalid syntax error when selecting from the view.  (Bug
     #17526)

   * Assignments of values to variables of type *Note `TEXT': blob.
     were handled incorrectly in stored routines.  (Bug #17225)

   * `DATE_ADD()' and `DATE_SUB()' returned `NULL' when the result date
     was on the day `'9999-12-31''.  (Bug #12356)

   * The `DATA DIRECTORY' table option did not work for `TEMPORARY'
     tables.  (Bug #8706)

   * Bug #10952 may cause inadvertent data loss. A fix for this bug was
     included in MySQL 5.0.23, but the approach used caused a loss of
     intended functionality. Because of this, that fix has been
     reverted in MySQL 5.0.24. As a consequence, the risk of
     inadvertent data loss still exists (see Bug #10952).


File: manual.info,  Node: news-5-0-23,  Next: news-5-0-22,  Prev: news-5-0-24,  Up: news-5-0-x

D.1.73 Changes in MySQL 5.0.23 (Not released)
---------------------------------------------

MySQL 5.0.23 was never officially released.

This section documents all changes and bug fixes that have been applied
since the last official MySQL release. If you would like to receive
more fine-grained and personalized _update alerts_ about fixes that are
relevant to the version and features you use, please consider
subscribing to _MySQL Enterprise_ (a commercial MySQL offering). For
more details, please see http://www.mysql.com/products/enterprise.

*Functionality Added or Changed*

   * *Incompatible Change*: For `GRANT' and `REVOKE', `ON *' previously
     granted and revoked privileges for the default database if there
     was a default database and global privileges if there was none. Now
     `ON *' requires a default database and produces an error if there
     is none.

   * *Important Change*: *MySQL Cluster*: The status variables
     `Ndb_connected_host' and `Ndb_connected_port' were renamed to
     `Ndb_config_from_host' and `Ndb_config_from_port', respectively.

   * *MySQL Cluster*: The limit of 2048 ordered indexes per cluster has
     been lifted.  There is now no upper limit on the number of ordered
     indexes (including `AUTO_INCREMENT' columns) that may be used.
     (Bug #14509)

   * The *Note `mysqldumpslow': mysqldumpslow. script has been moved
     from client RPM packages to server RPM packages. This corrects a
     problem where *Note `mysqldumpslow': mysqldumpslow. could not be
     used with a client-only RPM install, because it depends on *Note
     `my_print_defaults': my-print-defaults. which is in the server RPM.
     (Bug #20216)

   * Added the `log_queries_not_using_indexes' system variable.  (Bug
     #19616)

   * Added the `ssl_ca', `ssl_capath', `ssl_cert', `ssl_cipher', and
     `ssl_key' system variables, which display the values given using
     the corresponding command options. See *Note ssl-options::.  (Bug
     #19606)

   * SQL syntax for prepared statements now supports *Note `ANALYZE
     TABLE': analyze-table, *Note `OPTIMIZE TABLE': optimize-table, and
     *Note `REPAIR TABLE': repair-table.  (Bug #19308)

   * For a table with an `AUTO_INCREMENT' column, *Note `SHOW CREATE
     TABLE': show-create-table. now shows the next `AUTO_INCREMENT'
     value to be generated.  (Bug #19025)

   * The `ONLY_FULL_GROUP_BY' SQL mode now also applies to the `HAVING'
     clause.  That is, columns not named in the `GROUP BY' clause
     cannot be used in the `HAVING' clause if not used in an aggregate
     function.  (Bug #18739)

   * Added the `--set-charset' option to *Note `mysqlbinlog':
     mysqlbinlog. to enable the character set to be specified for
     processing binary log files.  (Bug #18351)

   * The bundled yaSSL library was upgraded to version 1.3.5. This
     improves handling of certain problems with SSL-related command
     options.  (Bug #17737)

   * Added the `--ssl-verify-server-cert' option to MySQL client
     programs. This option causes the server's Common Name value in its
     certificate to be verified against the host name used when
     connecting to the server, and the connection is rejected if there
     is a mismatch. Added `MYSQL_OPT_SSL_VERIFY_SERVER_CERT' option for
     the *Note `mysql_options()': mysql-options. C API function to
     enable this verification. This feature can be used to prevent
     man-in-the-middle attacks. Verification is disabled by default.
     (Bug #17208)

   * It is now possible to use `NEW.VAR_NAME' values within triggers as
     `INOUT' parameters to stored procedures.  (Bug #14635)

   * Added the `--angel-pid-file' option to `mysqlmanager' for
     specifying the file in which the angel process records its process
     ID when `mysqlmanager' runs in daemon mode.  (Bug #14106)

   * The *Note `mysql_get_ssl_cipher()': mysql-get-ssl-cipher. C API
     function was added.

   * The *Note `mysql_upgrade': mysql-upgrade. command has been
     converted from a shell script to a C program, so it is available on
     non-Unix systems such as Windows. This program should be run for
     each MySQL upgrade. See *Note mysql-upgrade::.

   * Binary distributions that include SSL support now are built using
     yaSSL when possible.

*Bugs Fixed*

   * *Security Fix*: A `NUL' byte within a comment in a statement
     string caused the rest of the string not to be written to the
     query log, permitting logging to be bypassed.  (Bug #17667,
     CVE-2006-0903)

   * *MySQL Cluster*: The *Note `ndb_mgm':
     mysql-cluster-programs-ndb-mgm. client command `ALL CLUSTERLOG
     STATISTICS=15' had no effect.  (Bug #20336)

   * *MySQL Cluster*: The failure of a data node when preparing to
     commit a transaction (that is, while the node's status was
     `CS_PREPARE_TO_COMMIT') could cause the failure of other cluster
     data nodes.  (Bug #20185)

   * *MySQL Cluster*: An internal formatting error caused some
     management client error messages to be unreadable.  (Bug #20016)

   * *MySQL Cluster*: Renaming a table in such a way as to move it to a
     different database failed to move the table's indexes.  (Bug
     #19967)

   * *MySQL Cluster*: Running management client commands while `mgmd'
     was in the process of disconnecting could cause the management
     server to fail.  (Bug #19932)

   * *MySQL Cluster*: Running `ALL START' in the *Note `NDB':
     mysql-cluster. management client or restarting multiple nodes
     simultaneously could under some circumstances cause the cluster to
     crash.  (Bug #19930)

   * *MySQL Cluster*: *Note `TEXT': blob. columns in Cluster tables
     having both an explicit primary key and a unique key were not
     correctly updated by *Note `REPLACE': replace.  statements.  (Bug
     #19906)

   * *MySQL Cluster*: The cluster's data nodes failed while trying to
     load data when `NoOfFrangmentLogFiles' was set equal to 1.  (Bug
     #19894)

   * *MySQL Cluster*: Restoring a backup with *Note `ndb_restore':
     mysql-cluster-programs-ndb-restore. failed when the backup had
     been taken from a cluster whose `DataMemory' had been completely
     used up.  (Bug #19852)

   * *MySQL Cluster*: Resources for unique indexes on Cluster table
     columns were incorrectly allocated, so that only one-fourth as
     many unique indexes as indicated by the value of
     `UniqueHashIndexes' could be created.  (Bug #19623)

   * *MySQL Cluster*: *Note `LOAD DATA LOCAL': load-data. failed to
     ignore duplicate keys in Cluster tables.  (Bug #19496)

   * *MySQL Cluster*: For *Note `ndb_mgmd':
     mysql-cluster-programs-ndb-mgmd, Valgrind revealed problems with a
     memory leak and a dependency on an uninitialized variable.  (Bug
     #19318, Bug #20333)

   * *MySQL Cluster*: A problem with error handling when
     `ndb_use_exact_count' was enabled could lead to incorrect values
     returned from queries using `COUNT()'. A warning is now returned
     in such cases.  (Bug #19202)

   * *MySQL Cluster*: *Note `TRUNCATE TABLE': truncate-table. failed on
     tables having *Note `BLOB': blob. or *Note `TEXT': blob. columns
     with the error `Lock wait timeout exceeded'.  (Bug #19201)

   * *MySQL Cluster*: `mysql-test-run.pl' started *Note `NDB':
     mysql-cluster. even for test cases that did not need it.  (Bug
     #19083)

   * *MySQL Cluster*: Stopping multiple nodes could cause node failure
     handling not to be completed.  (Bug #19039)

   * *MySQL Cluster*: The management client `ALL STOP' command shut
     down `mgmd' processes (as well as *Note `ndbd':
     mysql-cluster-programs-ndbd. processes).  (Bug #18966)

   * *MySQL Cluster*: *Note `TRUNCATE TABLE': truncate-table. failed to
     reset the `AUTO_INCREMENT' counter.  (Bug #18864)

   * *MySQL Cluster*: Repeated `CREATE' - *Note `INSERT': insert. -
     `DROP' operations on tables could in some circumstances cause the
     MySQL table definition cache to become corrupt, so that some *Note
     `mysqld': mysqld. processes could access table information but
     others could not.  (Bug #18595)

   * *MySQL Cluster*: Repeated use of the *Note `SHOW': show. and `ALL
     STATUS' commands in the *Note `ndb_mgm':
     mysql-cluster-programs-ndb-mgm. client could cause the `mgmd'
     process to crash.  (Bug #18591)

   * *MySQL Cluster*: *Note `ndbd': mysql-cluster-programs-ndbd.
     sometimes failed to start with the error `Node failure handling
     not completed' following a graceful restart.  (Bug #18550)

   * *MySQL Cluster*: Backups could fail for large clusters with many
     tables, where the number of tables approached `MaxNoOfTables'.
     (Bug #17607)

   * *MySQL Cluster*: An issue with *Note `ndb_mgmd':
     mysql-cluster-programs-ndb-mgmd. prevented more than 27 `mysqld'
     processes from connecting to a single cluster at one time.  (Bug
     #17150)

   * *MySQL Cluster*: Using `stale' *Note `mysqld': mysqld.  `.frm'
     files could cause a newly-restored cluster to fail. This situation
     could arise when restarting a MySQL Cluster using the `--initial'
     option while leaving connected *Note `mysqld': mysqld. processes
     running.  (Bug #16875)

   * *MySQL Cluster*: Data node failures could cause excessive CPU
     usage by *Note `ndb_mgmd': mysql-cluster-programs-ndb-mgmd.  (Bug
     #13987)

   * *MySQL Cluster*: Cluster system status variables were not updated
     properly.  (Bug #11459)

   * *MySQL Cluster*: Some queries having a `WHERE' clause of the form
     `c1=val1 OR c2 LIKE 'val2'' were not evaluated correctly. (Bug
     #17421)

   * *MySQL Cluster*: (NDBAPI): Update operations on blobs were not
     checked for illegal operations.

     *Note*:

     Read locks with blob update operations are now upgraded from read
     committed to read shared.

   * *Replication*: Valgrind revealed an issue with *Note `mysqld':
     mysqld. that was corrected: memory corruption in replication
     slaves when switching databases.  (Bug #19022)

   * *Replication*: The binary log would create an incorrect `DROP'
     query when creating temporary tables during replication.  (Bug
     #17263)

   * *Replication*: An invalid *Note `GRANT': grant. statement for
     which `Ok' was returned on a replication master caused an error on
     the slave and replication to fail.  (Bug #6774)

   * *Cluster API*: On big-endian platforms,
     `NdbOperation::write_attr()' did not update 32-bit fields
     correctly.  (Bug #19537)

   * A buffer overwrite error in Instance Manager caused a crash.  (Bug
     #20622)

   * On Windows, temporary tables containing ``:'' in the name could
     not be created.  (Bug #20616)

   * Valgrind revealed several issues with *Note `mysqld': mysqld.
     that were corrected: A dangling stack pointer being overwritten;
     possible uninitialized data in a string comparison; `syscall()'
     write parameter pointing to an uninitialized byte.  (Bug #20579,
     Bug #20769, Bug #20783, Bug #20791)

   * The `fill_help_tables.sql' file did not contain a `SET NAMES
     'utf8'' statement to indicate its encoding. This caused problems
     for some settings of the MySQL character set such as `big5'.  (Bug
     #20551)

   * The `fill_help_tables.sql' file did not load properly if the
     `ANSI_QUOTES' SQL mode was enabled.  (Bug #20542)

   * *Note `mysql_upgrade': mysql-upgrade. was missing from binary MySQL
     distributions.  (Bug #20403, Bug #18516, Bug #20556)

   * Several aspects of view privileges were being checked incorrectly.
     (Bug #20363, Bug #18681)

   * Queries using an indexed column as the argument for the `MIN()' and
     `MAX()' functions following an `ALTER TABLE .. DISABLE KEYS'
     statement returned `Got error 124 from storage engine' until
     `ALTER TABLE ... ENABLE KEYS' was run on the table.  (Bug #20357)

   * The thread for *Note `INSERT DELAYED': insert-delayed.  rows was
     maintaining a separate `AUTO_INCREMENT' counter, resulting in
     incorrect values being assigned if `DELAYED' and non-`DELAYED'
     inserts were mixed.  (Bug #20195)

   * On Linux, `libmysqlclient' when compiled with yaSSL using the
     `icc' compiler had a spurious dependency on C++ libraries.  (Bug
     #20119)

   * A number of dependency issues in the RPM `bench' and `test'
     packages caused installation of these packages to fail.  (Bug
     #20078)

   * A compatibility issue with NPTL (Native POSIX Thread Library) on
     Linux could result in a deadlock with *Note `FLUSH TABLES WITH
     READ LOCK': flush. under some conditions.  (Bug #20048)

   * Some outer joins were incorrectly converted to inner joins.  (Bug
     #19816) This regression was introduced by Bug #17146.

   * *Note `CREATE DATABASE': create-database, `RENAME DATABASE', and
     *Note `DROP DATABASE': drop-database. could deadlock in cases
     where there was a global read lock.  (Bug #19815)

   * The `WITH CHECK OPTION' was not enforced when a *Note `REPLACE':
     replace. statement was executed against a view.  (Bug #19789)

   * Multiple-table updates with `FEDERATED' tables could cause a
     server crash.  (Bug #19773)

   * `InnoDB' unlocked its data directory before committing a
     transaction, potentially resulting in nonrecoverable tables if a
     server crash occurred before the commit.  (Bug #19727)

   * Subqueries that produced a `BIGINT UNSIGNED' value were being
     treated as returning a signed value.  (Bug #19700)

   * `GROUP BY' on an expression that contained a cast to *Note
     `DECIMAL': numeric-types. produced an incorrect result.  (Bug
     #19667)

   * `MERGE' tables did not work reliably with *Note `BIT':
     numeric-types. columns.  (Bug #19648)

   * Re-execution of a prepared multiple-table *Note `DELETE': delete.
     statement that involves a trigger or stored function can result in
     a server crash.  (Bug #19634)

   * The range operator failed and caused a server crash for clauses of
     the form ` TBL_NAME.UNSIGNED_KEYPART NOT IN (NEGATIVE_CONST, ...)'.
     (Bug #19618)

   * *Note `CHECK TABLE': check-table. on a `MyISAM' table briefly
     cleared its `AUTO_INCREMENT' value, while holding only a read
     lock. Concurrent inserts to that table could use the wrong
     `AUTO_INCREMENT' value.  *Note `CHECK TABLE': check-table. no
     longer modifies the `AUTO_INCREMENT' value.  (Bug #19604)

   * Using `CONCAT(@USER_VAR, COL_NAME)', where COL_NAME is a column in
     an `INFORMATION_SCHEMA' table, could cause erroneous duplication
     of data in the query result.  (Bug #19599)

   * Some yaSSL public function names conflicted with those from
     OpenSSL, causing conflicts for applications that linked against
     both OpenSSL and a version of `libmysqlclient' that was built with
     yaSSL support. The yaSSL public functions now are renamed to avoid
     this conflict.  (Bug #19575)

   * A view definition that referred to an alias in the `HAVING' clause
     could be saved in the `.frm' file with the alias replaced by the
     expression that it referred to, causing failure of subsequent
     `SELECT * FROM VIEW_NAME ' statements.  (Bug #19573)

   * *Note `mysql': mysql. displayed `NULL' for strings that are empty
     or contain only spaces.  (Bug #19564)

   * `InnoDB' failed to increment the `handler_read_prev' counter.
     (Bug #19542)

   * Selecting from a view that used `GROUP BY' on a nonconstant
     temporal interval (such as `DATE(COL) + INTERVAL TIME_TO_SEC(COL)
     SECOND' could cause a server crash.  (Bug #19490)

   * *Note `mysqldump': mysqldump. did not dump the table name
     correctly for some table identifiers that contained unusual
     characters such as ``:''.  (Bug #19479)

   * On 64-bit Windows systems, `REGEXP' for regular expressions with
     exactly 31 characters did not work.  (Bug #19407)

   * An outer join of two views that was written using `{ OJ ... }'
     syntax could cause a server crash.  (Bug #19396)

   * Race conditions on certain platforms could cause the Instance
     Manager to fail to initialize.  (Bug #19391)

   * Use of the `--no-pager' option caused *Note `mysql': mysql. to
     crash.  (Bug #19363)

   * In the *Note `INFORMATION_SCHEMA.COLUMNS': columns-table.  table,
     the values for the `CHARACTER_MAXIMUM_LENGTH' and
     `CHARACTER_OCTET_LENGTH' columns were incorrect for multi-byte
     character sets.  (Bug #19236)

   * Multiple-table *Note `DELETE': delete. statements containing a
     subquery that selected from one of the tables being modified
     caused a server crash.  (Bug #19225)

   * On Windows, removal of binary log files would fail if the files
     were already open.  (Bug #19208)

   * Flushing the compression buffer (via *Note `FLUSH TABLE': flush.)
     no longer increases the size of an unmodified `ARCHIVE' table.
     (Bug #19204)

   * An *Note `ALTER TABLE': alter-table. operation that does not need
     to copy data, when executed on a table created prior to MySQL
     4.0.25, could result in a server crash for subsequent accesses to
     the table.  (Bug #19192)

   * SSL connections using yaSSL on OpenBSD could fail.  (Bug #19191)

   * Attempting to set the default value of an *Note `ENUM': enum. or
     *Note `SET': set. column to `NULL' caused a server crash.  (Bug
     #19145)

   * Use of uninitialized user variables in a subquery in the `FROM'
     clause resulted in invalid entries in the binary log.  (Bug #19136)

   * A *Note `CREATE TABLE': create-table. statement that created a
     table from a materialized view did not inherit default values from
     the underlying table.  (Bug #19089)

   * Index prefixes for `utf8' *Note `VARCHAR': char. columns did not
     work for *Note `UPDATE': update. statements.  (Bug #19080)

   * Premature optimization of nested subqueries in the `FROM' clause
     that refer to aggregate functions could lead to incorrect results.
     (Bug #19077)

   * The parser leaked memory when its stack needed to be extended.
     (Bug #18930)

   * *Note `BIT': numeric-types. columns in a table could cause joins
     that use the table to fail.  (Bug #18895)

   * The MySQL server startup script `/etc/init.d/mysql' (created from
     *Note `mysql.server': mysql-server.) is now marked to ensure that
     the system services `ypbind', `nscd', `ldap', and `NTP' are
     started first (if these are configured on the machine).  (Bug
     #18810)

   * The `COM_STATISTICS' command was changed in 5.0.3 to display
     session status variable values rather than global values. This
     causes *Note `mysqladmin status': mysqladmin.  information not to
     be useful for the `Slow queries' and `Opens' values. Now
     `COM_STATISTICS' displays the global values for `Slow queries' and
     `Opens'.  (Bug #18669)

   * `LOAD DATA FROM MASTER' would fail when trying to load the
     `INFORMATION_SCHEMA' database from the master, because the
     `INFORMATION_SCHEMA' system database would already exist on the
     slave.  (Bug #18607)

   * *Note `BLOB': blob. or *Note `TEXT': blob. arguments to or values
     returned from stored functions were not copied properly if too
     long and could become garbled.  (Bug #18587)

   * The `IN'-to-`EXISTS' transformation was making a reference to a
     parse tree fragment that was left out of the parse tree. This
     caused problems with prepared statements.  (Bug #18492)

   * *Note `mysqldump': mysqldump. produced garbled output for view
     definitions.  (Bug #18462)

   * The configuration information for building the embedded server on
     Windows was missing a file.  (Bug #18455)

   * In `mysqltest', `--sleep=0' had no effect. Now it correctly causes
     `sleep' commands in test case files to sleep for 0 seconds.  (Bug
     #18312)

   * *Note `INFORMATION_SCHEMA.TABLES': tables-table. provided
     inconsistent info about invalid views. This could cause server
     crashes or result in incorrect data being returned for queries
     that attempt to obtain information from `INFORMATION_SCHEMA'
     tables about views using stored functions.  (Bug #18282)

   * On Windows, corrected a crash stemming from differences in Visual
     C runtime library routines from POSIX behavior regarding invalid
     file descriptors.  (Bug #18275)

   * On Windows, terminating *Note `mysqld': mysqld. with `Control+C'
     could result in a crash during shutdown.  (Bug #18235)

   * Selecting data from a `MEMORY' table with a *Note `VARCHAR': char.
     column and a `HASH' index over it returned only the first row
     matched.  (Bug #18233)

   * The use of `MIN()' and `MAX()' on columns with an index prefix
     produced incorrect results in some queries.  (Bug #18206)

   * An entry in the `mysql.proc' table with an empty routine name
     caused access to the *Note `INFORMATION_SCHEMA.ROUTINES':
     routines-table. table to crash the server.  (Bug #18177)

   * A *Note `UNION': union. over more than 128 *Note `SELECT': select.
     statements that use an aggregate function failed.  (Bug #18175)

   * Updates to a `MEMORY' table caused the size of `BTREE' indexes for
     the table to increase.  (Bug #18160)

   * *Note `SELECT DISTINCT': select. queries sometimes returned only
     the last row.  (Bug #18068)

   * Returning the value of a system variable from a stored function
     caused a server crash.  (Bug #18037)

   * An update that used a join of a table to itself and modified the
     table on both sides of the join reported the table as crashed.
     (Bug #18036)

   * Race conditions on certain platforms could cause the Instance
     Manager to try to restart the same instance multiple times.  (Bug
     #18023)

   * For a reference to a nonexistent index in `FORCE INDEX', the error
     message referred to a column, not an index.  (Bug #17873)

   * The `sql_big_selects' system variable was not displayed by *Note
     `SHOW VARIABLES': show-variables.  (Bug #17849)

   * *Note `REPAIR TABLE': repair-table. did not restore the length for
     packed keys in tables created under MySQL 4.x, which caused them
     to appear corrupt to *Note `CHECK TABLE': check-table. but not to
     *Note `REPAIR TABLE': repair-table.  (Bug #17810)

   * Results from *Note `INFORMATION_SCHEMA.SCHEMATA': schemata-table.
     could contain uppercase information when `lower_case_table_names'
     was not 0.  (Bug #17661)

   * *Note `CREATE TABLE ... SELECT': create-table. did not always
     produce the proper column default value in `TRADITIONAL' SQL mode.
     (Bug #17626)

   * A range access optimizer heuristic was invalid, causing some
     queries to be much slower in MySQL 5.0 than in 4.0.  (Bug #17379,
     Bug #18940)

   * *Note `mysqldump': mysqldump. would not dump views that had become
     invalid because a table named in the view definition had been
     dropped. Instead, it quit with an error message. Now you can
     specify the `--force' option to cause *Note `mysqldump':
     mysqldump. to keep going and write an SQL comment containing the
     view definition to the dump output.  (Bug #17371)

   * The `--core-file-size' option for *Note `mysqld_safe':
     mysqld-safe. was effective only for `root'.  (Bug #17353)

   * On Windows, multiple clients simultaneously attempting to perform
     *Note `ALTER TABLE': alter-table. operations on an `InnoDB' table
     could deadlock.  (Bug #17264)

   * Revised memory allocation for local objects within stored
     functions and triggers to avoid memory leak for repeated function
     or trigger invocation.  (Bug #17260)

   * Multiple calls to a stored procedure that selects from
     `INFORMATION_SCHEMA' could cause a server crash.  (Bug #17204)

   * Views created from prepared statements inside of stored procedures
     were created with a definition that included both `SQL_CACHE' and
     `SQL_NO_CACHE'.  (Bug #17203)

   * *Note `mysqldump': mysqldump. wrote an extra pair of *Note `DROP
     DATABASE': drop-database. and *Note `CREATE DATABASE':
     create-database. statements if run with the `--add-drop-database'
     option and the database contained views.  (Bug #17201)

   * A `Table ... doesn't exist' error could occur for statements that
     called a function defined in another database.  (Bug #17199)

   * For certain *Note `CREATE TABLE ... SELECT': create-table.
     statements, the selected values were truncated when inserted into
     the new table.  (Bug #17048)

   * *Note `ALTER TABLE': alter-table. on a table created prior to
     5.0.3 would cause table corruption if the *Note `ALTER TABLE':
     alter-table. did one of the following:

        * Change the default value of a column.

        * Change the table comment.

        * Change the table password.

     (Bug #17001)

   * `MyISAM' table deadlock was possible if one thread issued a *Note
     `LOCK TABLES': lock-tables.  request for write locks and then an
     administrative statement such as *Note `OPTIMIZE TABLE':
     optimize-table, if between the two statements another client
     meanwhile issued a multiple-table *Note `SELECT': select. for some
     of the locked tables.  (Bug #16986)

   * Symlinking `.mysql_history' to `/dev/null' to suppress statement
     history saving by *Note `mysql': mysql. did not work.  (*Note
     `mysql': mysql. deleted the symlink and recreated `.mysql_history'
     as a regular file, and then wrote history to it.)  (Bug #16803)

   * Concatenating the results of multiple constant subselects produced
     incorrect results.  (Bug #16716)

   * Privilege checking on the contents of the *Note
     `INFORMATION_SCHEMA.VIEWS': views-table. table was insufficiently
     restrictive.  (Bug #16681)

   * *Note `mysqlcheck': mysqlcheck. tried to check views instead of
     ignoring them.  (Bug #16502)

   * `IS_USED_LOCK()' could return an incorrect connection identifier.
     (Bug #16501)

   * Concurrent reading and writing of privilege structures could crash
     the server.  (Bug #16372)

   * Grant table modifications sometimes did not refresh the in-memory
     tables if the host name was `''' or not specified.  (Bug #16297)

   * The `sql_notes' and `sql_warnings' system variables were not
     always displayed correctly by *Note `SHOW VARIABLES':
     show-variables. (for example, they were displayed as `ON' after
     being set to `OFF').  (Bug #16195)

   * The `max_length' metadata value for columns created from
     `CONCAT()' could be incorrect when the collation of an argument
     differed from the collation of the `CONCAT()' itself.  In some
     contexts such as *Note `UNION': union, this could lead to
     truncation of the column contents.  (Bug #15962)

   * The server no longer uses a signal handler for signal 0 because it
     could cause a crash on some platforms.  (Bug #15869)

   * `InnoDB' does not support `SPATIAL' indexes, but did not prevent
     creation of such an index.  (Bug #15860)

   * Long multiple-row *Note `INSERT': insert.  statements could take a
     very long time for some multi-byte character sets.  (Bug #15811)

   * The `system_time_zone' and `version_*' system variables could not
     be accessed using `SELECT @@VAR_NAME' syntax.  (Bug #15684, Bug
     #12792)

   * `EXPLAIN ... SELECT INTO' caused the client to hang.  (Bug #15463)

   * Nested natural joins worked executed correctly when executed as a
     nonprepared statement could fail with an `Unknown column
     'COL_NAME' in 'field list'' error when executed as a prepared
     statement, due to a name resolution problem.  (Bug #15355)

   * The `MD5()' and `SHA()' functions treat their arguments as
     case-sensitive strings. But when they are compared, their
     arguments were compared as case-insensitive strings, which leads
     to two function calls with different arguments (and thus different
     results) compared as being identical. This can lead to a wrong
     decision made in the range optimizer and thus to an incorrect
     result set.  (Bug #15351)

   * Invalid escape sequences in option files caused MySQL programs
     that read them to abort.  (Bug #15328)

   * Re-executing a stored procedure with a complex stored procedure
     cursor query could lead to a server crash.  (Bug #15217)

   * *Note `CREATE TABLE ... SELECT ...': create-table. statements that
     used a stored function explicitly or implicitly (through a view)
     resulted in a `Table not locked' error.  (Bug #15137, Bug #12472)

   * An invalid comparison between keys with index prefixes over
     multi-byte character fields could lead to incorrect result sets if
     the selected query execution plan used a range scan by an index
     prefix over a `UTF8' character field.  This also caused incorrect
     results under similar circumstances with many other character sets.
     (Bug #14896)

   * A view with a nonexistent account in the `DEFINER' clause caused
     *Note `SHOW CREATE VIEW': show-create-view. to fail. Now *Note
     `SHOW CREATE VIEW': show-create-view. issues a warning instead.
     (Bug #14875)

   * For *Note `BOOLEAN': numeric-types. mode full-text searches on
     nonindexed columns, `NULL' rows generated by a `LEFT JOIN' caused
     incorrect query results.  (Bug #14708, Bug #25637)

   * *Note `SHOW CREATE TABLE': show-create-table. did not display the
     `AUTO_INCREMENT' column attribute if the SQL mode was `MYSQL323' or
     `MYSQL40'. This also affected *Note `mysqldump': mysqldump, which
     uses *Note `SHOW CREATE TABLE': show-create-table. to get table
     definitions.  (Bug #14515)

   * Some queries were slower in 5.0 than in 4.1 because some 4.1
     cost-evaluation code had not been merged into 5.0.  (Bug #14292)

   * The binary log lacked character set information for table names
     when dropping temporary tables.  (Bug #14157)

   * The result from `CONV()' is a string, but was not always treated
     the same way as a string when converted to a real value for an
     arithmetic operation.  (Bug #13975)

   * RPM packages had spurious dependencies on Perl modules and other
     programs.  (Bug #13634)

   * *Note `REPLACE': replace. statements caused activation of `UPDATE'
     triggers, not `DELETE' and `INSERT' triggers.  (Bug #13479)

   * With settings of `read_buffer_size' >= 2G and
     `read_rnd_buffer_size' >=2G, *Note `LOAD DATA INFILE': load-data.
     failed with no error message or caused a server crash for files
     larger than 2GB.  (Bug #12982)

   * A `B-TREE' index on a `MEMORY' table erroneously reported
     duplicate entry error for multiple `NULL' values.  (Bug #12873)

   * Use of `CONVERT_TZ()' in a stored function or trigger (or in a
     stored procedure called from a stored function or trigger) caused
     an error.  (Bug #11081)

   * `LOAD_FILE()' returned an error if the file did not exist, rather
     than `NULL' as it should according to the manual.  (Bug #10418)

   * When *Note `myisamchk': myisamchk. needed to rebuild a table,
     `AUTO_INCREMENT' information was lost.  (Bug #10405)

   * For certain *Note `CREATE VIEW': create-view.  statements, the
     server did not detect invalid subqueries within the `SELECT ' part.
     (Bug #7549)

   * Within a trigger, *Note `SET': set-option.  statements used the
     SQL mode of the invoking statement, not the mode in effect at
     trigger creation time.  (Bug #6951)

   * Some queries that used `ORDER BY' and `LIMIT' performed quickly in
     MySQL 3.23, but slowly in MySQL 4.x/5.x due to an optimizer
     problem.  (Bug #4981)

   * The `basedir' and `tmpdir' system variables could not be accessed
     using `@@VAR_NAME' syntax.  (Bug #1039)


File: manual.info,  Node: news-5-0-22,  Next: news-5-0-21,  Prev: news-5-0-23,  Up: news-5-0-x

D.1.74 Changes in MySQL 5.0.22 (24 May 2006)
--------------------------------------------

This is a security fix release for the previous production release
family.

This section documents all changes and bug fixes that have been applied
since the last official MySQL release. If you would like to receive
more fine-grained and personalized _update alerts_ about fixes that are
relevant to the version and features you use, please consider
subscribing to _MySQL Enterprise_ (a commercial MySQL offering). For
more details, please see http://www.mysql.com/products/enterprise.

*Bugs Fixed*

   * *Security Fix*: An SQL-injection security hole has been found in
     multi-byte encoding processing. The bug was in the server,
     incorrectly parsing the string escaped with the *Note
     `mysql_real_escape_string()': mysql-real-escape-string. C API
     function.

     This vulnerability was discovered and reported by Josh Berkus
     <josh@postgresql.org> and Tom Lane <tgl@sss.pgh.pa.us> as part of
     the inter-project security collaboration of the OSDB consortium.
     For more information about SQL injection, please see the following
     text.

     Discussion

     An SQL injection security hole has been found in multi-byte
     encoding processing. An SQL injection security hole can include a
     situation whereby when a user supplied data to be inserted into a
     database, the user might inject SQL statements into the data that
     the server will execute. With regards to this vulnerability, when
     character set-unaware escaping is used (for example,
     `addslashes()' in PHP), it is possible to bypass the escaping in
     some multi-byte character sets (for example, SJIS, BIG5 and GBK).
     As a result, a function such as `addslashes()' is not able to
     prevent SQL-injection attacks. It is impossible to fix this on the
     server side. The best solution is for applications to use
     character set-aware escaping offered by a function such *Note
     `mysql_real_escape_string()': mysql-real-escape-string.

     However, a bug was detected in how the MySQL server parses the
     output of *Note `mysql_real_escape_string()':
     mysql-real-escape-string. As a result, even when the character
     set-aware function *Note `mysql_real_escape_string()':
     mysql-real-escape-string. was used, SQL injection was possible.
     This bug has been fixed.

     Workarounds

     If you are unable to upgrade MySQL to a version that includes the
     fix for the bug in *Note `mysql_real_escape_string()':
     mysql-real-escape-string.  parsing, but run MySQL 5.0.1 or higher,
     you can use the `NO_BACKSLASH_ESCAPES' SQL mode as a workaround.
     (This mode was introduced in MySQL 5.0.1.) `NO_BACKSLASH_ESCAPES'
     enables an SQL standard compatibility mode, where backslash is not
     considered a special character. The result will be that queries
     will fail.

     To set this mode for the current connection, enter the following
     SQL statement:

          SET sql_mode='NO_BACKSLASH_ESCAPES';

     You can also set the mode globally for all clients:

          SET GLOBAL sql_mode='NO_BACKSLASH_ESCAPES';

     This SQL mode also can be enabled automatically when the server
     starts by using the command-line option
     `--sql-mode=NO_BACKSLASH_ESCAPES' or by setting
     `sql-mode=NO_BACKSLASH_ESCAPES' in the server option file (for
     example, `my.cnf' or `my.ini', depending on your system).  (Bug
     #8378, CVE-2006-2753) See also Bug #8303.

   * *Replication*: The dropping of a temporary table whose name
     contained a backtick ('``'') character was not correctly written
     to the binary log, which also caused it not to be replicated
     correctly.  (Bug #19188)

   * The client libraries were not compiled for position-independent
     code on Solaris-SPARC and AMD x86_64 platforms.  (Bug #18091, Bug
     #13159, Bug #14202)

   * Running *Note `myisampack': myisampack. followed by *Note
     `myisamchk': myisamchk. with the `--unpack' option would corrupt
     the `AUTO_INCREMENT' key.  (Bug #12633)

   * The patch for Bug #8303 broke the fix for Bug #8378 and was
     reverted.

     In string literals with an escape character (`\') followed by a
     multi-byte character that had (`\') as its second byte, the
     literal was not interpreted correctly. Now only next byte now is
     escaped, and not the entire multi-byte character. This means it is
     a strict reverse of the *Note `mysql_real_escape_string()':
     mysql-real-escape-string.  function.


File: manual.info,  Node: news-5-0-21,  Next: news-5-0-20a,  Prev: news-5-0-22,  Up: news-5-0-x

D.1.75 Changes in MySQL 5.0.21 (02 May 2006)
--------------------------------------------

This MySQL 5.0.21 release includes the patches for recently reported
security vulnerabilites in the MySQL client/server protocol. We would
like to thank Stefano Di Paola <stefano.dipaola@wisec.it> for finding
and reporting these to us.

This is a bugfix release for the current production release family.

This section documents all changes and bug fixes that have been applied
since the last official MySQL release. If you would like to receive
more fine-grained and personalized _update alerts_ about fixes that are
relevant to the version and features you use, please consider
subscribing to _MySQL Enterprise_ (a commercial MySQL offering). For
more details, please see http://www.mysql.com/products/enterprise.

*Functionality Added or Changed*

   * *Security Enhancement*: Added the global `max_prepared_stmt_count'
     system variable to limit the total number of prepared statements
     in the server. This limits the potential for denial-of-service
     attacks based on running the server out of memory by preparing huge
     numbers of statements. The current number of prepared statements
     is available through the `prepared_stmt_count' system variable.
     (Bug #16365)

   * *MySQL Cluster*: It is now possible to perform a partial start of
     a cluster. That is, it is now possible to bring up the cluster
     without first running *Note `ndbd `--initial'':
     mysql-cluster-programs-ndbd. on all configured data nodes.  (Bug
     #18606)

   * *MySQL Cluster*: Added the `--nowait-nodes' startup option for
     *Note `ndbd': mysql-cluster-programs-ndbd, making it possible to
     skip specified nodes without waiting for them to start when
     starting the cluster. See *Note mysql-cluster-programs-ndbd::.

   * *MySQL Cluster*: It is now possible to install MySQL with Cluster
     support to a nondefault location and change the search path for
     font description files using either the `--basedir' or
     `--character-sets-dir' options.  (Previously in MySQL 5.0, *Note
     `ndbd': mysql-cluster-programs-ndbd. searched only the default
     path for character sets.)

   * *Packaging*: The `MySQL-shared-compat-5.0.X-.i386.rpm' shared
     compatibility RPMs no longer contain libraries for MySQL 5.1. This
     avoids a conflict because the 5.0 and 5.1 libraries share the same
     soname number. They now contain libraries for MySQL 3.23, 4.0,
     4.1, and 5.0 only.  (Bug #19288)

   * The default for the `innodb_thread_concurrency' system variable
     was changed to `8'.  (Bug #15868)

   * Server and clients ignored the `--sysconfdir' option that was
     passed to `configure'. The directory specified by this option, if
     set, now is used as one of the standard locations in which to look
     for option files.  (Bug #15069)

   * In result set metadata, the `MYSQL_FIELD.length' value for *Note
     `BIT': numeric-types. columns now is reported in number of bits.
     For example, the value for a `BIT(9)' column is 9. (Formerly, the
     value was related to number of bytes.)  (Bug #13601)

*Bugs Fixed*

   * *Security Fix*: Invalid arguments to `DATE_FORMAT()' caused a
     server crash. Thanks to Jean-David Maillefer for discovering and
     reporting this problem to the Debian project and to Christian
     Hammers from the Debian Team for notifying us of it.  (Bug #20729,
     CVE-2006-3469)

   * *Security Fix*: A malicious client, using specially crafted invalid
     `COM_TABLE_DUMP' packets was able to trigger an exploitable buffer
     overflow on the server. Thanks to Stefano Di Paola
     <stefano.dipaola@wisec.it> for finding and reporting this bug.
     (CVE-2006-1518)

   * *Security Fix*: A malicious client, using specially crafted
     invalid login or `COM_TABLE_DUMP' packets was able to read
     uninitialized memory, which potentially, though unlikely in MySQL,
     could have led to an information disclosure. (, ) Thanks to
     Stefano Di Paola <stefano.dipaola@wisec.it> for finding and
     reporting this bug.  (CVE-2006-1516, CVE-2006-1517)

   * *MySQL Cluster*: A simultaneous *Note `DROP TABLE': drop-table. and
     table update operation utilising a table scan could trigger a node
     failure.  (Bug #18597)

   * *MySQL Cluster*: When multiple node restarts were attempted
     without permitting each restart to complete, the error message
     returned was `Array index out of bounds' rather than `Too many
     crashed replicas'.  (Bug #18349)

   * *MySQL Cluster*: In a 2-node cluster with a node failure,
     restarting the node with a low value for `StartPartialTimeout'
     could cause the cluster to come up partitioned (`split-brain'
     issue).

     A similar issue could occur when the cluster was first started
     with a sufficiently low value for this parameter.  (Bug #16447,
     Bug #18612)

   * *MySQL Cluster*: On systems with multiple network interfaces, data
     nodes would get `stuck' in startup phase 2 if the interface
     connecting them to the management server was working on node
     startup while the interface interconnecting the data nodes
     experienced a temporary outage.  (Bug #15695)

   * *MySQL Cluster*: On slow networks or CPUs, the management client
     *Note `SHOW': show. command could sometimes erroneously show all
     data nodes as being master nodes belonging to nodegroup 0.  (Bug
     #15530)

   * *MySQL Cluster*: *Note `TRUNCATE TABLE': truncate-table. did not
     reset the `AUTO_INCREMENT' counter for `MyISAM' tables when issued
     inside a stored procedure.

     *Note*:

     This bug did not affect `InnoDB' tables.

     In addition, *Note `TRUNCATE TABLE': truncate-table.  does not
     reset the `AUTO_INCREMENT' counter for *Note `NDB': mysql-cluster.
     tables regardless of when it is called.

     (Bug #14945) See also Bug #18864.

   * *MySQL Cluster*: Unused open handlers for tables in which the
     metadata had changed were not properly closed. This could result
     in stale results from *Note `NDB': mysql-cluster. tables following
     an *Note `ALTER TABLE': alter-table. statement.  (Bug #13228)

   * *MySQL Cluster*: Uninitialized internal variables could lead to
     unexpected results.  (Bug #11033, Bug #11034)

   * *MySQL Cluster*: When attempting to create an index on a *Note
     `BIT': numeric-types. or *Note `BLOB': blob. column, `Error 743:
     Unsupported character set in table or index' was returned instead
     of `Error 906: Unsupported attribute type in index'.

   * *Replication*: *Note `CREATE VIEW': create-view. statements would
     not be replicated to the slave if the
     `--replicate-wild-ignore-table' rule was enabled.  (Bug #18715)

   * *Replication*: Updating a field value when also requesting a lock
     with `GET_LOCK()' would cause slave servers in a replication
     environment to terminate.  (Bug #17284)

   * `InnoDB' could read a delete mark from its system tables
     incorrectly.  (Bug #19217)

   * Corrected a syntax error in `mysql-test-run.sh'.  (Bug #19190)

   * Index corruption could occur in cases when `key_cache_block_size'
     was not a multiple of the `myisam-block-size' value (for example,
     with `--key_cache_block_size=1536' and `--myisam-block-size=1024').
     (Bug #19079)

   * The optimizer could cause a server crash or use a nonoptimal
     subset of indexes when evaluating whether to use `Index
     Merge/Intersection' variant of `index_merge' optimization.  (Bug
     #19021)

   * A missing `DBUG_RETURN()' caused the server to emit a spurious
     error message: `missing DBUG_RETURN or DBUG_VOID_RETURN macro in
     function "open_table"'.  (Bug #18964)

   * Creating a table in an `InnoDB' database with a column name that
     matched the name of an internal `InnoDB' column (including
     `DB_ROW_ID', `DB_TRX_ID', `DB_ROLL_PTR' and `DB_MIX_ID') would
     cause a crash. MySQL now returns Error 1005 `Cannot create table'
     with `errno' set to -1.  (Bug #18934)

   * MySQL would not compile on Linux distributions that use the
     `tinfo' library.  (Bug #18912)

   * `mysql_reconnect()' sent a `SET NAMES' statement to the server,
     even for pre-4.1 servers that do not understand the statement.
     (Bug #18830)

   * For a reference to a nonexistent stored function in a stored
     routine that had a `CONTINUE' handler, the server continued as
     though a useful result had been returned, possibly resulting in a
     server crash.  (Bug #18787)

   * For single-*Note `SELECT': select. union constructs of the form
     (SELECT ... ORDER BY ORDER_LIST1 [LIMIT N]) ORDER BY ORDER_LIST2,
     the `ORDER BY' lists were concatenated and the `LIMIT' clause was
     ignored.  (Bug #18767)

   * Conversion of a number to a `CHAR UNICODE' string returned an
     invalid result.  (Bug #18691)

   * `UNCOMPRESS(NULL)' could cause subsequent `UNCOMPRESS()' calls to
     return `NULL' for legal non-`NULL' arguments.  (Bug #18643)

   * If the second or third argument to `BETWEEN' was a constant
     expression such as `'2005-09-01 - INTERVAL 6 MONTH' and the other
     two arguments were columns, `BETWEEN' was evaluated incorrectly.
     (Bug #18618)

   * A *Note `LOCK TABLES': lock-tables. statement that failed could
     cause `MyISAM' not to update table statistics properly, causing a
     subsequent *Note `CHECK TABLE': check-table. to report table
     corruption.  (Bug #18544)

   * The yaSSL library returned a cipher list in a manner incompatible
     with OpenSSL.  (Bug #18399)

   * `InnoDB' did not use a consistent read for `CREATE ... SELECT' when
     `innodb_locks_unsafe_for_binlog' was set.  (Bug #18350)

   * *Note `DROP DATABASE': drop-database. did not drop stored routines
     associated with the database if the database name was longer than
     21 characters.  (Bug #18344)

   * The euro sign (`€') was not stored correctly in columns using the
     `latin1_german1_ci' or `latin1_general_ci' collation.  (Bug #18321)

   * A recent change caused the *Note `mysql': mysql. client not to
     display `NULL' values correctly and to display numeric columns
     left-justified rather than right-justified. The problems have been
     corrected.  (Bug #18265)

   * `COUNT(*)' on a `MyISAM' table could return different results for
     the base table and a view on the base table.  (Bug #18237)

   * `EXTRACT(QUARTER FROM DATE)' returned unexpected results.  (Bug
     #18100)

   * Executing *Note `SELECT': select. on a large table that had been
     compressed within *Note `myisampack': myisampack.  could cause a
     crash.  (Bug #17917)

   * Casting a string to *Note `DECIMAL': numeric-types.  worked, but
     casting a trimmed string (using `LTRIM()' or `RTRIM()') resulted
     in loss of decimal digits.  (Bug #17043)

   * `mysql-test-run' could not be run as `root'.  (Bug #17002)

   * Queries of the form `SELECT DISTINCT TIMESTAMP_COLUMN WHERE
     DATE_FUNCTION(TIMESTAMP_COL) = CONSTANT' did not return all
     matching rows.  (Bug #16710)

   * IA-64 RPM packages for Red Hat and SuSE Linux that were built with
     the `icc' compiler incorrectly depended on `icc' runtime libraries.
     (Bug #16662)

   * `MySQL-shared-compat-5.0.13-0.i386.rpm',
     `MySQL-shared-compat-5.0.15-0.i386.rpm',
     `MySQL-shared-compat-5.0.18-0.i386.rpm',
     `MySQL-shared-compat-5.0.19-0.i386.rpm',
     `MySQL-shared-compat-5.0.20-0.i386.rpm', and
     `MySQL-shared-compat-5.0.20a-0.i386.rpm' incorrectly depended on
     `glibc' 2.3 and could not be installed on a `glibc' 2.2 system.
     (Bug #16539)

   * The presence of multiple equalities in a condition after reading a
     constant table could cause the optimizer not to use an index.
     This resulted in certain queries being much slower than in MySQL
     4.1.  (Bug #16504)

   * Within a trigger, `CONNECTION_ID()' did not return the connection
     ID of the thread that caused the trigger to be activated.  (Bug
     #16461)

   * For tables created in a MySQL 4.1 installation upgraded to MySQL
     5.0 and up, multiple-table updates could update only the first
     matching row.  (Bug #16281)

   * A query using WHERE (COLUMN_1, COLUMN_2) IN ((VALUE_1, VALUE_2)[,
     (..., ...), ...]) would return incorrect results.  (Bug #16248)

   * For *Note `mysql.server': mysql-server, if the `basedir' option
     was specified after `datadir' in an option file, the setting for
     `datadir' was ignored and assumed to be located under `basedir'.
     (Bug #16240)

   * If the first argument to `BETWEEN' was a *Note `DATE': datetime. or
     *Note `TIME': time. column of a view and the other arguments were
     constants, `BETWEEN' did not perform conversion of the constants
     to the appropriate temporary type, resulting in incorrect
     evaluation.  (Bug #16069)

   * After calling `FLUSH STATUS', the `max_used_connections' variable
     did not increment for existing connections and connections which
     use the thread cache.  (Bug #15933)

   * Lettercase in database name qualifiers was not consistently
     handled properly in queries when `lower_case_table_names' was set
     to 1.  (Bug #15917)

   * *Note `DELETE': delete. and *Note `UPDATE': update. statements
     that used large `NOT IN (VALUE_LIST)' clauses could use large
     amounts of memory.  (Bug #15872)

   * `InnoDB' failure to release an adaptive hash index latch could
     cause a server crash if the query cache was enabled.  (Bug #15758)

   * `LAST_INSERT_ID()' in a stored function or trigger returned zero. .
     (Bug #15728)

   * *Note `DELETE': delete. with `LEFT JOIN' for `InnoDB' tables could
     crash the server if `innodb_locks_unsafe_for_binlog' was enabled.
     (Bug #15650)

   * When running a query that contained a `GROUP_CONCAT(SELECT
     GROUP_CONCAT(...)  )', the result was `NULL' except in the
     `ROLLUP' part of the result, if there was one.  (Bug #15560)

   * Use of `CONVERT_TZ()' in a view definition could result in
     spurious syntax or access errors.  (Bug #15153)

   * `CAST(DOUBLE AS SIGNED INT)' for large DOUBLE values outside the
     signed integer range truncated the result to be within range, but
     the result sometimes had the wrong sign, and no warning was
     generated.  (Bug #15098)

   * For `InnoDB' tables, an expression of the form `COL_NAME BETWEEN
     COL_NAME2 - INTERVAL X DAY AND COL_NAME2 + INTERVAL X DAY' when
     used in a join returned incorrect results.  (Bug #14360)

   * Prevent recursive views caused by using *Note `RENAME TABLE':
     rename-table. on a view after creating it.  (Bug #14308)

   * *Note `INSERT DELAYED': insert-delayed. into a view caused an
     infinite loop.  (Bug #13683)

   * Avoid trying to include `<asm/atomic.h>' when it doesn't work in
     C++ code.  (Bug #13621)

   * Within stored routines, user names were parsed incorrectly if they
     were enclosed within quotation marks.  (Bug #13310)

   * The server was always built as though
     `--with-extra-charsets=complex' had been specified.  (Bug #12076)


File: manual.info,  Node: news-5-0-20a,  Next: news-5-0-20,  Prev: news-5-0-21,  Up: news-5-0-x

D.1.76 Changes in MySQL 5.0.20a (18 April 2006)
-----------------------------------------------

This is a bugfix release for the current production release family. It
replaces MySQL 5.0.20.

*Additional SSL Support Information*
   * Please note that the original 5.0.20 announcement included inexact
     wording: SSL support is `included' in both server and client, but
     by default not `enabled'.  SSL can be enabled by passing the
     SSL-related options (`--ssl', `--ssl-key=...', `--ssl-cert=...',
     `--ssl-ca=...') when starting the server and the client or by
     specifying these options in an option file. For more information,
     see *Note secure-connections::.

   * With version 5.0.20a, SSL support is contained in all binaries for
     all Unix (including Linux) and Windows platforms except AIX,
     HP-UX, OpenServer 6, and the RPMs specific for RHAS3/RHAS4/SLES9
     on Itanium CPUs (`ia64'); It is also not contained in those for
     Novell Netware. We are trying to add these platforms in future
     versions.

*Bugs Fixed*

   * The fix for `Command line options are ignored for mysql client'
     has been revoked because it introduced an incompatible change in
     the way the *Note `mysql': mysql.  command-line client selects the
     server to connect to. In the worst case, this might have led to a
     client issuing commands to a server for which they were not
     intended, and this must not happen. To help all users in
     understanding this subject, *Note invoking-programs:: now includes
     additional explanation of how command options function with regard
     to host selection.  (Bug #16855)

   * The code of the `yaSSL' library has been improved to avoid a
     dependency on a C++ runtime library, so a link with pure C
     applications is now possible on additional (but not yet all)
     platforms. We are working on fixing the remaining issues.


File: manual.info,  Node: news-5-0-20,  Next: news-5-0-19,  Prev: news-5-0-20a,  Up: news-5-0-x

D.1.77 Changes in MySQL 5.0.20 (31 March 2006)
----------------------------------------------

*Functionality Added or Changed*

   * *MySQL Cluster*: The *Note `NDBCLUSTER': mysql-cluster. storage
     engine now supports *Note `INSERT IGNORE': insert. and *Note
     `REPLACE': replace.  statements. Previously, these statements
     failed with an error.  (Bug #17431)

   * *Replication*: Triggers from older servers that included no
     `DEFINER' clause in the trigger definition now execute with the
     privileges of the invoker (which on the slave is the slave SQL
     thread). Previously, replication slaves could not replicate such
     triggers.  (Bug #16266)

   * Builds for Windows, Linux, and Unix (except AIX) platforms now
     have SSL support enabled, in the server as well as in the client
     libraries. Because part of the SSL code is written in C++, this
     does introduce dependencies on the system's C++ runtime libraries
     in several cases, depending on compiler specifics.  (Bug #18195)

   * Large file support added to build for `QNX' platform.  (Bug #17336)

   * `InnoDB': The `InnoDB' storage engine now provides a descriptive
     error message if `ibdata' file information is omitted from
     `my.cnf'.  (Bug #16827)

   * Added the `--sysdate-is-now' option to *Note `mysqld': mysqld. to
     enable `SYSDATE()' to be treated as an alias for `NOW()'. See
     *Note date-and-time-functions::.  (Bug #15101)

   * Large file support was re-enabled for the MySQL server binary for
     the AIX 5.2 platform.  (Bug #13571)

   * The syntax for *Note `CREATE PROCEDURE': create-procedure.  and
     *Note `CREATE FUNCTION': create-function. statements now includes
     a `DEFINER' clause. The `DEFINER' value specifies the security
     context to be used when checking access privileges at routine
     invocation time if the routine has the `SQL SECURITY DEFINER'
     characteristic. See *Note create-procedure::, for more information.

     When *Note `mysqldump': mysqldump. is invoked with the
     `--routines' option, it now dumps the `DEFINER' value for stored
     routines.

*Bugs Fixed*

   * *MySQL Cluster*: A timeout in the handling of an `ABORT' condition
     with more that 32 operations could yield a node failure.  (Bug
     #18414)

   * *MySQL Cluster*: A node restart immediately following a *Note
     `CREATE TABLE': create-table. would fail.

     *Important*:

     This fix supports 2-node Clusters only.

     (Bug #18385)

   * *MySQL Cluster*: In event of a node failure during a rollback, a
     `false' lock could be established on the backup for that node,
     which lock could not be removed without restarting the node.  (Bug
     #18352)

   * *MySQL Cluster*: The cluster created a crashed replica of a table
     having an ordered index--or when logging was not enabled, of a
     table having a table or unique index--leading to a crash of the
     cluster following 8 successive restarts.  (Bug #18298)

   * *MySQL Cluster*: When replacing a failed master node, the
     replacement node could cause the cluster to crash from a buffer
     overflow if it had an excessively large amount of data to write to
     the cluster log.  (Bug #18118)

   * *MySQL Cluster*: Certain queries using `ORDER BY ... ASC' in the
     `WHERE' clause could return incorrect results.  (Bug #17729)

   * *MySQL Cluster*: If a *Note `mysql': mysql. or other client could
     not parse the result set returned from a *Note `mysqld': mysqld.
     process acting as an SQL node in a cluster, the client would crash
     instead of returning the appropriate error. For example, this
     could happen when the client attempted to use a character set was
     not available to the *Note `mysqld': mysqld.  (Bug #17380)

   * *MySQL Cluster*: Some query cache statistics were not always
     correctly reported for Cluster tables.  (Bug #16795)

   * *MySQL Cluster*: Restarting nodes were permitted to start and join
     the cluster too early.  (Bug #16772)

   * *MySQL Cluster*: Inserting and deleting *Note `BLOB': blob.
     column values while a backup was in process could cause data nodes
     to shut down.  (Bug #14028)

   * *MySQL Cluster*: The server would not compile with *Note `NDB':
     mysql-cluster. support on AIX 5.2.  (Bug #10776)

   * *Replication*: Use of *Note `TRUNCATE TABLE': truncate-table. for a
     `TEMPORARY' table on a master server was propagated to slaves
     properly, but slaves did not decrement the
     `Slave_open_temp_tables' counter properly.  (Bug #17137)

   * *Replication*: The `DEFINER' value for stored routines was not
     replicated.  (Bug #15963)

   * A `SELECT ... ORDER BY ...' from a view defined using a function
     could crash the server. An example of such a view is `CREATE VIEW
     v1 AS SELECT SQRT(c1) FROM t1'.  (Bug #18386)

   * `InnoDB' had a memory leak for duplicate-key errors with tables
     having 90 columns or more.  (Bug #18384)

   * A *Note `DELETE': delete. using a subquery could crash the server.
     (Bug #18306)

   * If a row was inserted inside a stored procedure using the
     parameters passed to the procedure in the INSERT statement, the
     resulting binary log entry was not escaped properly.  (Bug #18293)

   * If `InnoDB' encountered a `HA_ERR_LOCK_TABLE_FULL' error and
     rolled back a transaction, the transaction was still written to
     the binary log.  (Bug #18283)

   * When using `ORDER BY' with a nonstring column inside
     `GROUP_CONCAT()' the result's character set was converted to
     binary.  (Bug #18281) See also Bug #14169.

   * Complex queries with nested joins could cause a server crash.
     (Bug #18279)

   * For `InnoDB' tables created in MySQL 4.1 or earlier, or created in
     5.0 or later with compact format, updating a row so that a long
     column is updated or the length of some column changes, `InnoDB'
     later would fail to reclaim the *Note `BLOB': blob. storage space
     if the row was deleted.  (Bug #18252)

   * If `InnoDB' ran out of buffer space for row locks and adaptive
     hashes, the server would crash. Now `InnoDB' rolls back the
     transaction.  (Bug #18238)

   * Views that incorporated tables from the `INFORMATION_SCHEMA'
     database resulted in a server crash when queried.  (Bug #18224)

   * *Note `REPAIR TABLE': repair-table, *Note `OPTIMIZE TABLE':
     optimize-table, and *Note `ALTER TABLE': alter-table. operations on
     transactional tables (or on tables of any type on Windows) could
     corrupt triggers associated with those tables.  (Bug #18153)

   * The server could deadlock under heavy load while writing to the
     binary log.  (Bug #18116)

   * A `SELECT *' query on an `INFORMATION_SCHEMA' table by a user with
     limited privileges resulted in a server crash.  (Bug #18113)

   * Connecting to a server with a UCS2 default character set with a
     client using a non-UCS2 character set crashed the server.  (Bug
     #18004)

   * `MyISAM': Performing a bulk insert on a table referenced by a
     trigger would crash the table.  (Bug #17764)

   * Updating a view that filters certain rows to set a filtered out
     row to be included in the table caused infinite loop. For example,
     if the view has a WHERE clause of `salary > 100' then issuing an
     UPDATE statement of `SET salary = 200 WHERE id = 10', caused an
     infinite loop.  (Bug #17726)

   * `MyISAM': Keys for which the first part of the key was a *Note
     `CHAR': char. or *Note `VARCHAR': char. column using the UTF-8
     character set and longer than 254 bytes could become corrupted.
     (Bug #17705)

   * Updating the value of a Unicode *Note `VARCHAR': char. column with
     the result returned by a stored function would cause the insertion
     of ASCII characters into the column instead of Unicode, even where
     the function's return type was also declared as Unicode.  (Bug
     #17615)

   * For `FEDERATED' tables, a *Note `SELECT': select. statement with an
     `ORDER BY' clause did not return rows in the proper order.  (Bug
     #17377)

   * `SELECT ... WHERE COLUMN LIKE 'A%'', when COLUMN had a key and
     used the `latin2_czech_cs' collation, caused the wrong number of
     rows to be returned.  (Bug #17374)

   * A `LEFT JOIN' with a *Note `UNION': union. that selects literal
     values could crash the server.  (Bug #17366)

   * Checks for permissions on database operations could be performed
     in a case-insensitive manner (a user with permissions on database
     `MYDATABASE' could by accident get permissions on database
     `myDataBase'), if the privilege data were still cached from a
     previous check.  (Bug #17279)

   * Stored procedures that call UDFs and pass local string variables
     caused server crashes.  (Bug #17261)

   * If the `WHERE' condition of a query contained an `OR'-ed `FALSE'
     term, the set of tables whose rows cannot serve for
     null-complements in outer joins was determined incorrectly. This
     resulted in blocking possible conversions of outer joins into
     joins by the optimizer for such queries.  (Bug #17164)

   * `InnoDB' tables with an adaptive hash blocked other queries during
     *Note `CHECK TABLE': check-table.  statements while the entire
     hash was checked. This could be a long time for a large hash.
     (Bug #17126)

   * Stored routine names longer than 64 characters were silently
     truncated. Now the limit is properly enforced and an error occurs.
     (Bug #17015)

   * `InnoDB': The `LATEST FOREIGN KEY ERROR' section in the output of
     *Note `SHOW INNODB STATUS': show-innodb-status. was sometimes
     formatted incorrectly, causing problems with scripts that parsed
     the output of this statement.  (Bug #16814)

   * If the server was started with the `--skip-grant-tables' option, it
     was impossible to create a trigger or a view without explicitly
     specifying a `DEFINER' clause.  (Bug #16777)

   * The `FORMAT()' function returned an incorrect result when the
     client's `character_set_connection' value was `utf8'.  (Bug #16678)

   * Using `ORDER BY INTVAR ' within a stored procedure (where INTVAR
     is an integer variable or expression) would crash the server.

     *Note*:

     The use of an integer I in an `ORDER BY I' clause for sorting the
     result by the I ^th column is deprecated (and nonstandard). It
     should _not_ be used in new applications. See *Note select::.

     (Bug #16474)

   * Character set conversion of string constants for *Note `UNION':
     union. of constant and table column was not done when it was safe
     to do so.  (Bug #15949)

   * Triggers created in MySQL 5.0.16 and earlier could not be dropped
     after upgrading the server to 5.0.17 or later.  (Bug #15921)

   * The *Note `mysql_close()': mysql-close. C API function leaked
     handles for shared-memory connections on Windows.  (Bug #15846)

   * `COUNT(DISTINCT COL1, COL2)' and `COUNT(DISTINCT CONCAT(COL1,
     COL2))' operations produced different results if one of the
     columns was an indexed *Note `DECIMAL': numeric-types. column.
     (Bug #15745)

   * A *Note `SELECT': select. using a function against a nested view
     would crash the server.  (Bug #15683)

   * The server displayed garbage in the error message warning about
     bad assignments to *Note `DECIMAL': numeric-types.  columns or
     routine variables.  (Bug #15480)

   * During conversion from one character set to `ucs2', multi-byte
     characters with no `ucs2' equivalent were converted to multiple
     characters, rather than to `0x003F QUESTION MARK'.  (Bug #15375)

   * Certain combinations of joins with mixed `ON' and `USING' claused
     caused `unknown column' errors.  (Bug #15229)

   * `SELECT COUNT(*)' for a `MyISAM' table could return different
     results depending on whether an index was used.  (Bug #14980)

   * Attempting to access an `InnoDB' table after starting the server
     with `--skip-innodb' caused a server crash.  (Bug #14575)

   * Use of stored functions with `DISTINCT' or `GROUP BY' can produce
     incorrect results when `ORDER BY' is also used.  (Bug #13575)

   * The server would execute stored routines that had a nonexistent
     definer.  (Bug #13198)

   * *Note `mysql_config': mysql-config. returned incorrect libraries on
     `x86_64' systems.  (Bug #13158)

   * Loading of UDFs in a statically linked MySQL caused a server
     crash. UDF loading is now blocked if the MySQL server is
     statically linked.  (Bug #11835)


File: manual.info,  Node: news-5-0-19,  Next: news-5-0-18,  Prev: news-5-0-20,  Up: news-5-0-x

D.1.78 Changes in MySQL 5.0.19 (04 March 2006)
----------------------------------------------

*Functionality Added or Changed*

   * *Incompatible Change*: The `InnoDB' storage engine no longer
     ignores trailing spaces when comparing *Note `BINARY':
     binary-varbinary. or *Note `VARBINARY': binary-varbinary. column
     values. This means that (for example) the binary values `'a'' and
     `'a '' are now regarded as _unequal_ any time they are compared,
     as they are in `MyISAM' tables.

     See *Note binary-varbinary:: for more information about the *Note
     `BINARY': binary-varbinary. and *Note `VARBINARY':
     binary-varbinary. types.  (Bug #14189)

   * *MySQL Cluster*: More descriptive warnings are now issued when
     inappropriate logging parameters are set in `config.ini'.
     (Formerly, the warning issued was simply `Could not add logfile
     destination'.)  (Bug #11331)

   * *MySQL Cluster*: The *Note `ndb_mgm':
     mysql-cluster-programs-ndb-mgm. client commands `NODE_ID START' and
     `NODE_ID STOP' now work with management nodes as well as data
     nodes. However, using `ALL' for NODE_ID continues to affect all
     data nodes only.

   * *Note `mysql': mysql. no longer terminates data value display when
     it encounters a NUL byte. Instead, it displays NUL bytes as spaces.
     (Bug #16859)

   * New `charset' command added to *Note `mysql': mysql. command-line
     client. By typing `charset NAME' or `\C NAME' (such as `\C UTF8'),
     the client character set can be changed without reconnecting.
     (Bug #16217)

   * Added the `--wait-timeout' option to `mysqlmanager' to enable
     configuration of the timeout for dropping an inactive connection,
     and increased the default timeout from 30 seconds to 28,800
     seconds (8 hours).  (Bug #15980, Bug #12674)

   * The `INFORMATION_SCHEMA' now skips data contained in
     unlistable/unreadable directories rather than returning an error.
     (Bug #15851)

   * `InnoDB' now caches a list of unflushed files instead of scanning
     for unflushed files during a table flush operation. This improves
     performance when `--innodb_file_per_table' is set on a system with
     a large number of `InnoDB' tables.  (Bug #15653)

   * Added the `--port-open-timeout' option to *Note `mysqld': mysqld.
     to control how many seconds the server should wait for the TCP/IP
     port to become free if it cannot be opened.  (Bug #15591)

   * Wording of error 1329 changed to `No data - zero rows fetched,
     selected, or processed'.  (Bug #15206)

   * The message for error 1109 changed from `Unknown table ... in
     order clause' to `Unknown table ...  in field list'.  (Bug #15091)

   * A number of performance issues were resolved that had previously
     been encountered when using statements that repeatedly invoked
     stored functions. For example, calling `BENCHMARK()' using a stored
     function executed much more slowly than when invoking it with
     inline code that accomplished the same task. In most cases the two
     should now execute with approximately the same speed.  (Bug
     #14946, Bug #15014)

   * `mysqldump' now surrounds the `DEFINER', `SQL SECURITY DEFINER'
     and `WITH CHECK OPTION' clauses of a *Note `CREATE VIEW':
     create-view.  statement with "not in version" comments to prevent
     errors in earlier versions of MySQL.  (Bug #14871)

   * When using the `GROUP_CONCAT()' function where the
     `group_concat_max_len' system variable was greater than 512, the
     result type differed depending on whether an `ORDER BY' clause was
     included: *Note `BLOB': blob. if it was, *Note `VARBINARY':
     binary-varbinary. if it was not. (For nonbinary string arguments,
     the result was *Note `TEXT': blob. or *Note `VARCHAR': char.)

     Now an `ORDER BY' does not affect the result, which is *Note
     `VARBINARY': binary-varbinary.  (*Note `VARCHAR': char.) only if
     `group_concat_max_len' is less than or equal to 512, *Note `BLOB':
     blob.  (*Note `TEXT': blob.) otherwise.  (Bug #14169)

   * The *Note `mysql_ping()': mysql-ping. function will now retry if
     the `reconnect' flag is set and error `CR_SERVER_LOST' is
     encountered during the first attempt to ping the server.  (Bug
     #14057)

   * The `mysqltest' utility now converts all `CR/LF' combinations to
     `LF' to enable test cases intended for Windows to work properly on
     UNIX-like systems.  (Bug #13809)

   * `libmysqlclient' now uses versioned symbols with GNU ld.  (Bug
     #3074)

   * The client API now attempts to reconnect using TCP/IP if the
     `reconnect' flag is set, as is the case with sockets.  (Bug #2845)

   * Two new Hungarian collations are included: `utf8_hungarian_ci' and
     `ucs2_hungarian_ci'. These support the correct sort order for
     Hungarian vowels. However, they do not support the correct order
     for sorting Hungarian consonant contractions; we expect to fix
     this issue in a future release.

   * Several changes were made to make upgrades easier:

        * Added the *Note `mysql_upgrade': mysql-upgrade. program that
          checks all tables for incompatibilities with the current
          version of MySQL Server and repairs them if necessary. This
          program should be run for each MySQL upgrade (rather than
          *Note `mysql_fix_privilege_tables':
          mysql-fix-privilege-tables.). See *Note mysql-upgrade::.

        * Added the `FOR UPGRADE' option for the *Note `CHECK TABLE':
          check-table. statement. This option checks whether tables are
          incompatible with the current version of MySQL Server.

        * Added the `--check-upgrade' to *Note `mysqlcheck':
          mysqlcheck. that invokes *Note `CHECK TABLE': check-table.
          with the `FOR UPGRADE' option.

*Bugs Fixed*

   * *MySQL Cluster*: Cluster log file paths were truncated to 128
     characters. They may now be as long as `MAX_PATH' (the maximum
     path length permitted by the operating system).  (Bug #17411)

   * *MySQL Cluster*: Following multiple forced shutdowns and restarts
     of data nodes, *Note `DROP DATABASE': drop-database. could fail.
     (Bug #17325)

   * *MySQL Cluster*: The `REDO' log would become corrupted (and thus
     unreadable) in some circumstances, due to a failure in the query
     handler.  (Bug #17295)

   * *MySQL Cluster*: An *Note `UPDATE': update. with an inner join
     failed to match any records if both tables in the join did not
     have a primary key.  (Bug #17257)

   * *MySQL Cluster*: A *Note `DELETE': delete. with a join in the
     `WHERE' clause failed to retrieve any records if both tables in
     the join did not have a primary key.  (Bug #17249)

   * *MySQL Cluster*: The error message returned by *Note `perror
     `--ndb'': perror. was prefixed with `OS error code' instead of `NDB
     error code'.  (Bug #17235)

   * *MySQL Cluster*: In some cases, *Note `LOAD DATA INFILE':
     load-data. did not load all data into *Note `NDB': mysql-cluster.
     tables.  (Bug #17081)

   * *MySQL Cluster*: *Note `ndb_delete_all':
     mysql-cluster-programs-ndb-delete-all. ran out of memory when
     processing tables containing *Note `BLOB': blob.  columns.  (Bug
     #16693)

   * *MySQL Cluster*: A *Note `BIT': numeric-types. column whose offset
     and length totaled 32 caused the cluster to crash.  (Bug #16125)

   * *MySQL Cluster*: `UNIQUE' keys in Cluster tables were limited to
     225 bytes in length.  (Bug #15918)

   * *MySQL Cluster*: The `ndb_autodiscover' test failed sporadically
     due to a node not being permitted to connect to the cluster.  (Bug
     #15619)

   * *MySQL Cluster*: *Note `NDB': mysql-cluster. returned an incorrect
     `Can't find file error' for OS error 24; this has been changed to
     `Too many open files'.  (Bug #15020)

   * *MySQL Cluster*: No error message was generated for setting
     `NoOfFragmentLogFiles' too low.  (Bug #13966)

   * *MySQL Cluster*: No error message was generated for setting
     `MaxNoOfAttributes' too low.  (Bug #13965)

   * *MySQL Cluster*: When running more than one management process in
     a cluster:

        * *Note `ndb_mgm -c HOST:PORT -e "NODE_ID STOP"':
          mysql-cluster-programs-ndb-mgm.  stopped a management process
          running only on the same system where the command was issued.

        * *Note `ndb_mgm -e "SHUTDOWN"':
          mysql-cluster-programs-ndb-mgm. failed to shut down any
          management processes at all.

     (Bug #12045, Bug #12124)

   * *MySQL Cluster*: *Note `ndb_mgm -c HOST:PORT -e "NODE_ID STOP"':
     mysql-cluster-programs-ndb-mgm. would stop a management process
     running only on the same system on which the command was issued.

   * *MySQL Cluster*: *Note `ndb_mgm -e "SHUTDOWN"':
     mysql-cluster-programs-ndb-mgm. failed to shut down any management
     processes at all.

   * *Replication*: For a transaction that used `MyISAM' and `InnoDB'
     tables, interruption of the transaction due to a dropped
     connection on a master server caused slaves to lose synchrony.
     (Bug #16559)

   * *Replication*: The `--replicate-do' and `--replicate-ignore'
     options were not being enforced on multiple-table statements.
     (Bug #16487, Bug #15699)

   * *Replication*: Previously, a stored function invocation was
     written to the binary log as `DO FUNC_NAME()' if the invocation
     changes data and occurs within a nonlogged statement, or if the
     function invokes a stored procedure that produces an error. These
     invocations now are logged as `SELECT FUNC_NAME()' instead for
     better control over error code checking (slave servers could stop
     due to detecting a different error than occurred on the master).
     (Bug #14769)

   * *Replication*: *Note `BIT': numeric-types. fields were not properly
     handled when using row-based replication.  (Bug #13418)

   * *Cluster API*: Upon the completion of a scan where a key request
     remained outstanding on the primary replica and a starting node
     died, the scan did not terminate. This caused incomplete error
     handling for the failed node.  (Bug #15908)

   * `type_decimal' failed with the prepared statement protocol.  (Bug
     #17826)

   * The MySQL server could crash with out of memory errors when
     performing aggregate functions on a *Note `DECIMAL':
     numeric-types. column.  (Bug #17602)

   * Using `DROP FUNCTION IF EXISTS FUNC_NAME' to drop a user-defined
     function caused a server crash if the server was running with the
     `--skip-grant-tables' option.  (Bug #17595)

   * Data truncations on non-`UNIQUE' indexes could crash `InnoDB' when
     using multi-byte character sets.  (Bug #17530)

   * A natural join between `INFORMATION_SCHEMA' tables failed.  (Bug
     #17523)

   * A stored procedure failed to return data the first time it was
     called per connection.  (Bug #17476)

   * For certain `MERGE' tables, the optimizer wrongly assumed that
     using `index_merge/intersection' was too expensive.  (Bug #17314)

   * The parser permitted `CREATE AGGREGATE FUNCTION' for creating
     stored functions, even though `AGGREGATE' does not apply. (It is
     used only for *Note `CREATE FUNCTION': create-function. only when
     creating user-defined functions.)  (Bug #16896)

   * Cursors in stored routines could cause a server crash.  (Bug
     #16887)

   * Triggers created without `BEGIN' and `END' clauses resulted in
     `You have an error in your SQL syntax' errors when dumping and
     replaying a binary log.  (Bug #16878)

   * Using *Note `ALTER TABLE': alter-table. to increase the length of a
     `BINARY(M)' column caused column values to be padded with spaces
     rather than `0x00' bytes.  (Bug #16857)

   * A *Note `RETURN': return. statement within a trigger caused a
     server crash.  *Note `RETURN': return. is no longer permitted
     within triggers. To exit immediately, use *Note `LEAVE':
     leave-statement.  (Bug #16829)

   * For a MySQL 5.0 server, using MySQL 4.1 tables in queries with a
     `GROUP BY' clause could result in buffer overrun or a server crash.
     (Bug #16752)

   * An *Note `INSERT': insert. statement in a stored procedure
     corrupted the binary log.  (Bug #16621)

   * If the query optimizer transformed a `GROUP BY' clause in a
     subquery, it did not also transform the `HAVING' clause if there
     was one, producing incorrect results.  (Bug #16603)

   * In a highly concurrent environment, a server crash or deadlock
     could result from execution of a statement that used stored
     functions or activated triggers coincident with alteration of the
     tables used by these functions or triggers.  (Bug #16593)

   * A race condition could occur when dropping the adaptive hash index
     for a B-tree page in `InnoDB'.  (Bug #16582)

   * When evaluation of the test in a *Note `CASE': case-statement.
     failed in a stored procedure that contained a `CONTINUE' handler,
     execution resumed at the beginning of the CASE statement instead
     of at the end.  (Bug #16568)

   * Clients compiled from source with the `--without-readline' did not
     save command history from session to session.  (Bug #16557)

   * The *Note `DECIMAL': numeric-types. data type was not being
     handled correctly with prepared statements.  (Bug #16511)

   * Instance Manager searched wrong location for password file on some
     platforms.  (Bug #16499)

   * *Note `UPDATE': update. statement crashed multi-byte character set
     `FULLTEXT' index if update value was almost identical to initial
     value only differing in some spaces being changed to &nbsp;.  (Bug
     #16489)

   * Certain nested `LEFT JOIN' operations were not properly optimized.
     (Bug #16393)

   * Dropping `InnoDB' constraints named `TBL_NAME_ibfk_0' could crash
     the server.  (Bug #16387)

   * *Note `SELECT': select. with `GROUP BY' on a view could cause a
     server crash.  (Bug #16382)

   * An invalid stored routine could not be dropped.  (Bug #16303)

   * `InnoDB': After upgrading an `InnoDB' table having a `VARCHAR
     BINARY' column created in MySQL 4.0 to MySQL 5.0, update
     operations on the table would cause the server to crash.  (Bug
     #16298)

   * Parallel builds occasionally failed on Solaris.  (Bug #16282)

   * A call to the `IF()' function using decimal arguments could return
     incorrect results.  (Bug #16272)

   * MySQL server dropped client connection for certain *Note `SELECT':
     select. statements against views defined that used `MERGE'
     algorithm.  (Bug #16260)

   * `InnoDB' used full explicit table locks in trigger processing.
     (Bug #16229)

   * Using `GROUP BY' on column used in `WHERE' clause could cause
     empty set to be returned.  (Bug #16203)

   * A memory leak caused warnings on slaves for certain statements
     that executed without warning on the master.  (Bug #16175)

   * The `FORCE INDEX' keyword in a query would prevent an index merge
     from being used where an index merge would normally be chosen by
     the optimizer.  (Bug #16166)

   * Setting `InnoDB' path settings to an empty string caused `InnoDB'
     storage engine to crash upon server startup.  (Bug #16157)

   * The *Note `mysql_stmt_sqlstate()': mysql-stmt-sqlstate. C API
     function incorrectly returned an empty string rather than
     `'00000'' when no error occurred.  (Bug #16143)

   * `MIN()' and `MAX()' operations were not optimized for views.  (Bug
     #16016)

   * Performing a *Note `RENAME TABLE': rename-table. on an `InnoDB'
     table when the server was started with the
     `--innodb_file_per_table' option and the data directory was a
     symlink caused a server crash.  (Bug #15991)

   * Executing a *Note `SHOW CREATE VIEW': show-create-view.  query of
     an invalid view caused the `mysql_next_result()' function of
     `libMySQL.dll' to hang.  (Bug #15943)

   * Test suite `sp' test left behind tables when the test failed that
     could cause future tests to fail.  (Bug #15866)

   * `STR_TO_DATE(1,NULL)' caused a server crash.  (Bug #15828,
     CVE-2006-3081)

   * `CAST(... AS TIME)' operations returned different results when
     using versus not using prepared-statement protocol.  (Bug #15805)

   * Issuing a *Note `DROP USER': drop-user. statement could cause some
     users to encounter a ` HOSTNAME is not permitted to connect to
     this MySQL server' error.  (Bug #15775)

   * The contents of `fill_help_tables.sql' could not be loaded in
     strict SQL mode.  (Bug #15760)

   * `fill_help_tables.sql' was not included in binary distributions
     for several platforms.  (Bug #15759)

   * Certain *Note `LEAVE': leave-statement.  statements in stored
     procedures were not properly optimized.  (Bug #15737)

   * The *Note `mysql_real_connect()': mysql-real-connect. C API
     function incorrectly reset the `MYSQL_OPT_RECONNECT' option to its
     default value.  (Bug #15719)

   * Created a user function with an empty string (that is, `CREATE
     FUNCTION ''()'), was accepted by the server. Following this,
     calling *Note `SHOW FUNCTION STATUS': show-function-status. would
     cause the server to crash.  (Bug #15658)

   * Trying to compile the server on Windows generated a stack overflow
     warning due to a recursive definition of the internal
     `Field_date::store()' method.  (Bug #15634)

   * In some cases the query optimizer did not properly perform
     multiple joins where inner joins followed left joins, resulting in
     corrupted result sets.  (Bug #15633)

   * Certain permission management statements could create a `NULL'
     host name for a user, resulting in a server crash.  (Bug #15598)

   * Improper memory handling for stored routine variables could cause
     memory overruns and binary log corruption.  (Bug #15588)

   * The `COALESCE()' function truncated data in a *Note `TINYTEXT':
     blob. column.  (Bug #15581)

   * Binary distributions for Solaris contained files with group
     ownership set to the nonexisting `wheel' group.  Now the `bin'
     group is used.  (Bug #15562)

   * The absence of a table in the left part of a left or right join
     was not checked prior to name resolution, which resulted in a
     server crash.  (Bug #15538)

   * A *Note `SELECT': select. of a stored function that references the
     `INFORMATION_SCHEMA' could crash the server.  (Bug #15533)

   * Characters in the `gb2312' and `euckr' character sets which did
     not have Unicode mappings were truncated.  (Bug #15377)

   * Certain subqueries where the inner query was the result of a
     aggregate function would return different results with MySQL 5.0
     than with MySQL 4.1.

     Subselects could also return wrong results when the query cache
     and grouping were involved.  (Bug #15347)

   * Performing an `ORDER BY' on an indexed *Note `ENUM': enum. column
     returned error.  (Bug #15308)

   * A *Note `SELECT': select. query which contained a `GROUP_CONCAT()'
     and an `ORDER BY' clause against the `INFORMATION_SCHEMA' resulted
     in an empty result set.  (Bug #15307)

   * The `NOT FOUND' condition handler for stored procedures did not
     distinguish between a `NOT FOUND' condition and an exception or
     warning.  (Bug #15231)

   * The `SELECT' privilege was required for triggers that performed no
     selects.  (Bug #15196)

   * An attempt to open a table that requires a disabled storage engine
     could cause a server crash.  (Bug #15185)

   * The `UPDATE' privilege was required for triggers that performed no
     updates.  (Bug #15166)

   * Tarball install package was missing a proper
     `fill_help_tables.sql' file.  (Bug #15151)

   * Setting `innodb_log_file_size' to a value greater than 4G crashed
     the server.  (Bug #15108)

   * When multiple handlers are created for the same MySQL error number
     within nested blocks, the outermost handler took precedence.  (Bug
     #15011)

   * A statement containing `GROUP BY' and `HAVING' clauses could
     return incorrect results when the `HAVING' clause contained logic
     that returned `FALSE' for every row.  (Bug #14927)

   * Stored routines that contained only a single statement were not
     written properly to the dumpfile when using `mysqldump'.  (Bug
     #14857)

   * Killing a long-running query containing a subquery could cause a
     server crash.  (Bug #14851)

   * *Note `GRANT': grant. statements specifying schema names that
     included underscore characters (that is, `my_schema') did not
     match if the underscore was escaped in the *Note `GRANT': grant.
     statement (that is, `GRANT ALL ON `my\_schema` ...').  (Bug #14834)

   * Generating an `AUTO_INCREMENT' value through a `FEDERATED' table
     did not set the value returned by `LAST_INSERT_ID()'.  (Bug #14768)

   * `SUBSTRING_INDEX()' could yield inconsistent results when applied
     with the same arguments to consecutive rows in a query.  (Bug
     #14676)

   * Running out of diskspace in the location specified by the `tmpdir'
     option resulted in incorrect error message.  (Bug #14634)

   * `InnoDB': Comparison of indexed `VARCHAR CHARACTER SET ucs2
     COLLATE ucs2_bin' columns using `LIKE' could fail.  (Bug #14583)

   * A stored procedure with an undefined variable and an exception
     handler would hang the client when called.  (Bug #14498)

   * A `FULLTEXT' query in a prepared statement could result in
     unexpected behavior.  (Bug #14496)

   * Using an aggregate function as the argument for a `HAVING' clause
     resulted in the aggregate function always returning `FALSE'.  (Bug
     #14274)

   * The use of *Note `LOAD INDEX': load-index. within a stored routine
     was permitted and caused the server to crash.

     *Note*:

     *Note `LOAD INDEX': load-index. statements within stored routines
     _are not supported_, and now yield an error if attempted. This
     behavior is intended.

     (Bug #14270)

   * A *Note `COMMIT': commit. statement followed by a *Note `ALTER
     TABLE': alter-table. statement on a BDB table caused server crash.
     (Bug #14212)

   * The *Note `mysql_stmt_store_result()': mysql-stmt-store-result. C
     API function could not be used for a prepared statement if a
     cursor had been opened for the statement.  (Bug #14013)

   * `SET sql_mode = N', where N > 31, did not work properly.  (Bug
     #13897)

   * Attempts to create `FULLTEXT' indexes on *Note `VARCHAR': char.
     columns larger than 1000 bytes resulted in error.  (Bug #13835)

   * The *Note `RENAME TABLE': rename-table. statement did not move
     triggers to the new table.  (Bug #13525)

   * The length of a `VARCHAR()' column that used the `utf8' character
     set would increase each time the table was re-created in a stored
     procedure or prepared statement, eventually causing the *Note
     `CREATE TABLE': create-table. statement to fail.  (Bug #13134)

   * Instance Manager erroneously accepted a list of instance
     identifiers for the `START INSTANCE' and `STOP INSTANCE' commands
     (should accept only a single identifier).  (Bug #12813)

   * A prepared statement created from a `SELECT ...  LIKE' query (such
     as `PREPARE stmt1 FROM 'SELECT col_1 FROM tedd_test WHERE col_1
     LIKE ?';') would begin to produce erratic results after being
     executed repeatedly numerous (thousands) of times.  (Bug #12734)

   * Multi-byte path names for *Note `LOAD DATA': load-data. and *Note
     `SELECT ... INTO OUTFILE': select. caused errors. Added the
     `character_set_filesystem' system variable, which controls the
     interpretation of string literals that refer to file names.  (Bug
     #12448)

   * Temporary table aliasing did not work inside stored functions.
     (Bug #12198)

   * The embedded server did not permit binding of columns to the
     `MYSQL_TYPE_VAR_STRING' data type in prepared statements.  (Bug
     #12070)

   * When Connector/ODBC or any other client called
     `my_init()'/`my_end()' several times, it caused corruption of
     charset data stored in `once_mem_pool'.  (Bug #11892)

   * Setting the `myisam_repair_threads' system variable to a value
     larger than 1 could cause corruption of large `MyISAM' tables.
     (Bug #11527)

   * The *Note `mysqlbinlog': mysqlbinlog. utility did not output
     `DELIMITER' statements, causing syntax errors for stored routine
     creation statements.  (Bug #11312)

   * The embedded server failed various tests in the automated test
     suite.  (Bug #10801, Bug #10925, Bug #15433, Bug #9633, Bug
     #10926, Bug #9631, Bug #10930, Bug #10911, Bug #9630, Bug #10924)

   * A large *Note `BIGINT': numeric-types. value specified in a
     `WHERE' clause could be treated differently depending on whether
     it is specified as a quoted string. (For example, `WHERE
     bigint_col = 17666000000000000000' versus `WHERE bigint_col =
     '17666000000000000000'').  (Bug #9088)

   * *Note `CHECKSUM TABLE': checksum-table. returned different values
     for `MyISAM' tables depending on whether the `QUICK' or `EXTENDED'
     option was used.  (Bug #8841)

   * Using the `TRUNCATE()' function with a negative number for the
     second argument on a *Note `BIGINT': numeric-types. column
     returned incorrect results.  (Bug #8461)

   * Issuing *Note `GRANT EXECUTE': grant. on a procedure would display
     any warnings related to the creation of the procedure.  (Bug #7787)

   * Repeated invocation of `my_init()' and `my_end()' caused
     corruption of character set data and connection failure.  (Bug
     #6536)

   * An *Note `INSERT ... SELECT': insert-select. statement between
     tables in a `MERGE' set can return errors when statement involves
     insert into child table from merge table or vice-versa.  (Bug
     #5390)


File: manual.info,  Node: news-5-0-18,  Next: news-5-0-17,  Prev: news-5-0-19,  Up: news-5-0-x

D.1.79 Changes in MySQL 5.0.18 (21 December 2005)
-------------------------------------------------

*Functionality Added or Changed*

   * The server treats stored routine parameters and local variables
     (and stored function return values) according to standard SQL.
     Previously, parameters, variables, and return values were treated
     as items in expressions and were subject to automatic (silent)
     conversion and truncation. Now the data type is observed. Data
     type conversion and overflow problems that occur in assignments
     result in warnings, or errors in strict mode. The `CHARACTER SET'
     clause for character data type declarations is used. Parameters,
     variables, and return values must be scalars; it is no longer
     possible to assign a row value.  Also, stored functions execute
     using the `sql_mode' value in force at function creation time
     rather than ignoring it. For more information, see *Note
     create-procedure::.  (Bug #13808, Bug #12903, Bug #9078, Bug
     #14161, Bug #13705, Bug #13909, Bug #15148, Bug #8769, Bug #8702,
     Bug #9572, Bug #8768)

   * It is now possible to build the server such that `MyISAM' tables
     can support up to 128 keys rather than the standard 64. This can
     be done by configuring the build using the option
     `--with-max-indexes=N ', where N<=128 is the maximum number of
     indexes to permit per table.  (Bug #10932)

*Bugs Fixed*

   * *MySQL Cluster*: If an abort by the Transaction Coordinator timed
     out, the abort condition was incorrectly handled, causing the
     transaction record to be released prematurely.  (Bug #15685)

   * *MySQL Cluster*: The `ndb_read_multi_range.test' script failed to
     drop a table, causing the test to fail.  (Bug #15675) See also Bug
     #15402.

   * *MySQL Cluster*: Under some circumstances, it was possible for a
     restarting node to undergo a forced shutdown.  (Bug #15632)

   * *MySQL Cluster*: A node which failed during cluster startup was
     sometimes not removed from the internal list of active nodes.
     (Bug #15587)

   * *Replication*: A replication slave server could sometimes crash on
     a `BEFORE UPDATE' trigger if the *Note `UPDATE': update. query was
     not executed in the same database as the table with the trigger.
     (Bug #14614)

   * When a connection using yaSSL was aborted, the server would
     continue to try to read the closed socket, and the thread
     continued to appear in the output of *Note `SHOW PROCESSLIST':
     show-processlist. Note that this issue did not affect secure
     connection attempts using OpenSSL.  (Bug #15772)

   * `' API function *Note `mysql_stmt_prepare()': mysql-stmt-prepare.
     returned wrong field length for TEXT columns.  (Bug #15613)

   * `InnoDB': Having two tables in a parent-child relationship
     enforced by a foreign key where one table used
     `ROW_FORMAT=COMPACT' and the other used `ROW_FORMAT=REDUNDANT'
     could result in a MySQL server crash. Note that this problem did
     not exist prior to MySQL 5.0.3, when the compact row format for
     `InnoDB' was introduced.  (Bug #15550)

   * `BDB': A *Note `DELETE': delete, *Note `INSERT': insert, or *Note
     `UPDATE': update. of a `BDB' table could cause the server to crash
     where the query contained a subquery using an index read.  (Bug
     #15536)

   * Resolution of the argument to the `VALUES()' function to a variable
     inside a stored routine caused a server crash. The argument must
     be a table column.  (Bug #15441)

   * A left join on a column that having a `NULL' value could cause the
     server to crash.  (Bug #15268)

   * The output of *Note `mysqldump --triggers': mysqldump. did not
     contain the `DEFINER' clause in dumped trigger definitions.  (Bug
     #15110)

   * Reversing the order of operands in a `WHERE' clause testing a
     simple equality (such as `WHERE t1.col1 = t2.col2') would produce
     different output from *Note `EXPLAIN': explain.  (Bug #15106)

   * The output of *Note `SHOW TRIGGERS': show-triggers.  contained
     extraneous whitespace.  (Bug #15103)

   * Creating a trigger caused a server crash if the table or trigger
     database was not known because no default database had been
     selected.  (Bug #14863)

   * Column aliases were displayed incorrectly in a *Note `SELECT':
     select. from a view following an update to a base table of the
     view.  (Bug #14861)

   * `SHOW [FULL] COLUMNS' and *Note `SHOW INDEX': show-index. did not
     function with temporary tables.  (Bug #14387, Bug #15224)

   * The *Note `INFORMATION_SCHEMA.COLUMNS': columns-table.  table did
     not report the size of *Note `BINARY': binary-varbinary. or *Note
     `VARBINARY': binary-varbinary. columns.  (Bug #14271)

   * `InnoDB': If `foreign_key_checks' was 0, `InnoDB' permitted
     inconsistent foreign keys to be created.  (Bug #13778)

   * The server would not compile under Cygwin.  (Bug #13640)

   * *Note `DESCRIBE': describe. did not function with temporary tables.
     (Bug #12770)

   * Set functions could not be aggregated in outer subqueries.  (Bug
     #12762)

   * A race condition when creating temporary files caused a deadlock
     on Windows with threads in `Opening tables' or `Waiting for table'
     states.  (Bug #12071)


File: manual.info,  Node: news-5-0-17,  Next: news-5-0-16,  Prev: news-5-0-18,  Up: news-5-0-x

D.1.80 Changes in MySQL 5.0.17 (14 December 2005)
-------------------------------------------------

*Functionality Added or Changed*

   * *Replication*: The syntax for *Note `CREATE TRIGGER':
     create-trigger. now includes a `DEFINER' clause for specifying
     which access privileges to check at trigger invocation time. See
     *Note create-trigger::, for more information.

     Known issue

     If you attempt to replicate from a master server older than MySQL
     5.0.17 to a slave running MySQL 5.0.17 through 5.0.19, replication
     of *Note `CREATE TRIGGER': create-trigger.  statements fails on
     the slave with a `Definer not fully qualified error'. A workaround
     is to create triggers on the master using a version-specific
     comment embedded in each *Note `CREATE TRIGGER': create-trigger.
     statement:

          CREATE /*!50017 DEFINER = 'root'@'localhost' */ TRIGGER ... ;

     *Note `CREATE TRIGGER': create-trigger. statements written this
     way will replicate to newer slaves, which pick up the `DEFINER'
     clause from the comment and execute successfully.

     (Bug #16266)

   * Support files for compiling with Visual Studio 6 have been removed.
     (Bug #15094)

   * In the `latin5_turkish_ci' collation, the order of the characters
     `A WITH CIRCUMFLEX', `I WITH CIRCUMLEX', and `U WITH CIRCUMFLEX'
     was changed. If you have used these characters in any indexed
     columns, you should rebuild those indexes.  (Bug #13421)

   * Recursion is permitted in stored procedures. Recursive stored
     functions and triggers still are not permitted.  (Bug #10100)

   * Added a `DEFINER' column to the *Note
     `INFORMATION_SCHEMA.TRIGGERS': triggers-table. table.

   * Invoking a stored function or trigger creates a new savepoint
     level. When the function or trigger finishes, the previous
     savepoint level is restored.

     See also Bug #13825.

   * The maximum key length for `InnoDB' indexes was increased from
     1024 bytes to 3072 bytes for all builds. (In MySQL 5.0.15, the
     length was increased but only for 64-bit builds.)

   * Added the *Note `SHOW FUNCTION CODE': show-function-code. and
     *Note `SHOW PROCEDURE CODE': show-procedure-code. statements
     (available only for servers that have been built with debugging
     support). See *Note show-procedure-code::.

*Bugs Fixed*

   * *MySQL Cluster*: A forced cluster shutdown occurred when the
     management daemon was restarted with a changed `config.ini' file
     that added an API or SQL node.  (Bug #15512)

   * *MySQL Cluster*: There was a small window for a node failure to
     occur during a backup without an error being reported.  (Bug
     #15425)

   * *MySQL Cluster*: Using `ORDER BY PRIMARY_KEY_COLUMN' when
     selecting from a table having the primary key on a *Note
     `VARCHAR': char. column caused a forced shutdown of the cluster.
     (Bug #15240, Bug #15682, Bug #14828, Bug #15517)

   * *MySQL Cluster*: Under certain circumstances, when *Note `mysqld':
     mysqld.  connected to a cluster management server, the connection
     would fail before a node ID could be allocated.  (Bug #15215)

   * *MySQL Cluster*: Creating a table with packed keys failed silently.
     *Note `NDB': mysql-cluster. now supports the `PACK_KEYS' option to
     *Note `CREATE TABLE': create-table. correctly.  (Bug #14514)

   * *MySQL Cluster*: *Note `REPLACE': replace. failed when attempting
     to update a primary key value in a Cluster table.  (Bug #14007)

   * *Replication*: Stored functions making use of cursors were not
     replicated.  (Bug #14077)

   * *Replication*: On Windows, the server could crash during shutdown
     if both replication threads and normal client connection threads
     were active.  (Bug #11796)

   * *Replication*: `InnoDB': During replication, There was a failure
     to record events in the binary log that still occurred even in the
     event of a *Note `ROLLBACK': commit. For example, this sequence of
     commands:

          BEGIN;
          CREATE TEMPORARY TABLE t1 (a INT) ENGINE=INNODB;
          ROLLBACK;
          INSERT INTO t1 VALUES (1);

     would succeed on the replication master as expected. However, the
     *Note `INSERT': insert. would fail on the slave because the *Note
     `ROLLBACK': commit. would (erroneously) cause the *Note `CREATE
     TEMPORARY TABLE': create-table. statement not to be written to the
     binlog.  (Bug #7947)

   * Corrected an error-handling problem within stored routines on
     64-bit platforms.  (Bug #15630)

   * Slave SQL thread cleanup was not handled properly on Mac OS X when
     a statement was killed, resulting in a slave crash.  (Bug #15623,
     Bug #15668)

   * The `CREATE' test case in `mysql-test-run.pl' failed on AIX and
     SCO.  (Bug #15607)

   * A bug in `mysql-test/t/mysqltest.test' caused that test to fail.
     (Bug #15605)

   * A statement that produced a warning, when fetched using *Note
     `mysql_stmt_fetch()': mysql-stmt-fetch, did not produce a warning
     count according to *Note `mysql_warning_count()':
     mysql-warning-count.  (Bug #15510)

   * The database-changing code for stored routine handling caused an
     error-handling problem resulting in a server crash.  (Bug #15392)

   * The original Linux RPM packages (5.0.17-0) had an issue with a
     `zlib' dependency that would result in an error during an install
     or upgrade. They were replaced by new binaries, 5.0.17-1. Here is
     a list of the new RPM binaries:

        * MySQL-{Max,client,devel,server,shared,ndb*}-5.0.17-1.i386.rpm

        * MySQL-*-standard-5.0.17-1.rhel3.i386.rpm,
          MySQL-*-standard-5.0.17-1.rhel3.ia64.rpm,
          MySQL-*-standard-5.0.17-1.rhel3.x86_64.rpm

        * MySQL-*-pro-5.0.17-1.rhel3.i386.rpm,
          MySQL-*-pro-5.0.17-1.rhel3.ia64.rpm,
          MySQL-*-pro-5.0.17-1.rhel3.x86_64.rpm

        * MySQL-*-pro-gpl-5.0.17-1.rhel3.i386.rpm,
          MySQL-*-pro-gpl-5.0.17-1.rhel3.ia64.rpm,
          MySQL-*-pro-gpl-5.0.17-1.rhel3.x86_64.rpm

     (Bug #15223)

   * *Note `mysqld': mysqld. would not start on Windows 9X operating
     systems including Windows Me.  (Bug #15209)

   * Queries that select records based on comparisons to a set of
     column could crash the server if there was one index covering the
     columns, and a set of other noncovering indexes that taken
     together cover the columns.  (Bug #15204)

   * Selecting from a view processed with the temptable algorithm
     caused a server crash if the query cache was enabled.  (Bug #15119)

   * *Note `mysql --help': mysql. was missing a newline after the
     version string when the bundled `readline' library was not used.
     (Bug #15097)

   * Creating a view that referenced a stored function that selected
     from a view caused a crash upon selection from the view.  (Bug
     #15096)

   * The server crashed if compiled without any transactional storage
     engines.  (Bug #15047)

   * Multiple-table update operations were counting updates and not
     updated rows. As a result, if a row had several updates it was
     counted several times for the `rows matched' value but updated
     only once.  (Bug #15028)

   * Symbolic links did not function properly on Windows platforms.
     (Bug #14960, Bug #14310)

   * `ROW_COUNT()' returned an incorrect result after *Note `EXECUTE':
     execute. of a prepared statement.  (Bug #14956)

   * When using an aggregate function to select from a table that has a
     multiple-column primary key, adding `ORDER BY' to the query could
     produce an incorrect result.  (Bug #14920)

   * *Note `ANALYZE TABLE': analyze-table. did not properly update
     table statistics for a `MyISAM' table with a `FULLTEXT' index
     containing stopwords, so a subsequent *Note `ANALYZE TABLE':
     analyze-table.  would not recognize the table as having already
     been analyzed.  (Bug #14902)

   * Creating a view within a stored procedure could result in an out
     of memory error or a server crash.  (Bug #14885)

   * `GROUP BY' on a view column did not correctly account for the
     possibility that the column could contain `NULL' values.  (Bug
     #14850)

   * The *Note `mysql_stmt_fetch()': mysql-stmt-fetch. C API function
     could return `MYSQL_NO_DATA' for a `SELECT COUNT(*) FROM TBL_NAME
     WHERE 1 = 0' statement, which should return 1 row.  (Bug #14845)

   * Selecting from a view used `filesort' retrieval when faster
     retrieval was possible.  (Bug #14816)

   * `InnoDB': A race condition permitted two threads to drop a hash
     index simultaneously.  (Bug #14747)

   * *Note `SHOW CREATE TABLE': show-create-table. for a view could
     fail if the client had locked the view.  (Bug #14726)

   * The grammar for supporting the `DEFINER = CURRENT_USER' clause in
     *Note `CREATE VIEW': create-view. and *Note `ALTER VIEW':
     alter-view. was incorrect.  (Bug #14719)

   * `ALTER TABLE ... SET DEFAULT' had no effect.  (Bug #14693)

   * Using `ORDER BY' on a column from a view, when also selecting the
     column normally, and through an alias, caused a mistaken `Column
     'x' in order clause is ambiguous' error.  (Bug #14662)

   * *Note `SELECT': select. queries that began with an opening
     parenthesis were not being placed in the query cache.  (Bug #14652)

   * In a stored procedure, continuing (via a condition handler) after
     a failed variable initialization caused a server crash.  (Bug
     #14643)

   * A `LIMIT'-related optimization failed to take into account that
     `MyISAM' table indexes can be disabled, causing Error 124 when it
     tried to use such an index.  (Bug #14616)

   * *Note `mysqlhotcopy': mysqlhotcopy. tried to copy
     `INFORMATION_SCHEMA' tables.  (Bug #14610)

   * A server crash resulted from the following sequence of events: 1)
     With no default database selected, create a stored procedure with
     the procedure name explicitly qualified with a database name
     (`CREATE PROCEDURE DB_NAME.PROC_NAME ...'). 2) Create another
     stored procedure with no database name qualifier. 3) Execute *Note
     `SHOW PROCEDURE STATUS': show-procedure-status.  (Bug #14569)

   * *Note `mysqldump --triggers': mysqldump. did not account for the
     SQL mode and could dump trigger definitions with missing
     whitespace if the `IGNORE_SPACE' mode was enabled.  (Bug #14554)

   * *Note `CREATE TABLE TBL_NAME (...) SELECT ...':
     create-table-select. could crash the server and write invalid data
     into the `.frm' file if the *Note `CREATE TABLE': create-table. and
     *Note `SELECT': select. both contained a column with the same
     name. Also, if a default value is specified in the column
     definition, it is now actually used.  (Bug #14480)

   * The value of `INFORMATION_SCHEMA.TABLES.TABLE_TYPE' sometimes was
     reported as empty.  (Bug #14476)

   * `mysql_fix_privilege_tables.sql' contained an erroneous comment
     that resulted in an error when the file contents were processed.
     (Bug #14469)

   * Queries on `ARCHIVE' tables that used the `filesort' sorting
     method could result in a server crash.  (Bug #14433)

   * Creating a table containing an *Note `ENUM': enum. or *Note `SET':
     set. column from within a stored procedure or prepared statement
     caused a server crash later when executing the procedure or
     statement.  (Bug #14410)

   * For a table that had been opened with `HANDLER OPEN', issuing
     *Note `OPTIMIZE TABLE': optimize-table, *Note `ALTER TABLE':
     alter-table, or *Note `REPAIR TABLE': repair-table. caused a server
     crash.  (Bug #14397)

   * Declaring a stored routine variable to have a `DEFAULT' value that
     referred to a variable of the same name caused a server crash.
     (For example: `DECLARE x INT DEFAULT x') Now the `DEFAULT'
     variable is interpreted as referring to a variable in an outer
     scope, if there is one.  (Bug #14376)

   * Complex subqueries could cause improper internal query execution
     environment initialization and crash the server.  (Bug #14342)

   * Within a stored procedure, inserting with *Note `INSERT ...
     SELECT': insert-select. into a table with an `AUTO_INCREMENT'
     column did not generate the correct sequence number.  (Bug #14304)

   * Space truncation was being ignored when inserting into *Note
     `BINARY': binary-varbinary. or *Note `VARBINARY':
     binary-varbinary. columns. Now space truncation results in a
     warning, or an error in strict mode.  (Bug #14299)

   * Casting a *Note `FLOAT': numeric-types. or *Note `DOUBLE':
     numeric-types. whose value was less than `1.0E-06' to *Note
     `DECIMAL': numeric-types. would yield an inappropriate value.
     (Bug #14268)

   * `CAST(EXPR AS BINARY(N)') did not pad with 0x00 to a length of N
     bytes.  (Bug #14255)

   * Manual manipulation of the `mysql.proc' table could cause a server
     crash. This should not happen, but it is also not supported that
     the server will notice such changes.  (Bug #14233)

   * A *Note `UNION': union. of *Note `DECIMAL': numeric-types. columns
     could produce incorrect results.  (Bug #14216)

   * The maximum value of `MAX_ROWS' was handled incorrectly on 64-bit
     systems.  (Bug #14155)

   * `CHAR(... USING ...)' and `CONVERT(CHAR(...) USING ...)', though
     logically equivalent, could produce different results.  (Bug
     #14146)

   * The server could misinterpret old trigger definition files created
     before MySQL 5.0.17. Now they are interpreted correctly, but this
     takes more time and the server issues a warning that the trigger
     should be re-created.  (Bug #14090)

   * For a invalid view definition, selecting from the *Note
     `INFORMATION_SCHEMA.VIEWS': views-table. table or using *Note
     `SHOW CREATE VIEW': show-create-view. failed, making it difficult
     to determine what part of the definition was invalid. Now the
     server returns the definition and issues a warning.  (Bug #13818)

   * `InnoDB': Activity on an `InnoDB' table caused execution time for
     *Note `SHOW CREATE TABLE': show-create-table. for the table to
     increase.  (Bug #13762)

   * Within a stored procedure, exception handling for *Note `UPDATE':
     update. statements that caused a duplicate-key error caused a
     `Packets out of order' error for the following statement.  (Bug
     #13729)

   * Statements that implicitly commit a transaction are prohibited in
     stored functions and triggers. An attempt to create a function or
     trigger containing such a statement produces an error. (The
     originally reported symptom was that a trigger that dropped
     another trigger could cause a server crash. That problem was fixed
     by the patch for Bug #13343.)  (Bug #13627)

   * A newline character in a column alias in a view definition caused
     an error when selecting from the view later.  (Bug #13622)

   * Invoking a stored procedure within another stored procedure caused
     the server to crash.  (Bug #13549)

   * Warnings from a previous command were not being reset when
     fetching from a cursor.  (Bug #13524)

   * In some cases, a left outer join could yield an invalid result or
     cause the server to crash, due to a `MYSQL_DATA_TRUNCATED' error.
     (Bug #13488)

   * *Note `DELETE': delete. from `CSV' tables reported an incorrect
     rows-affected value.  (Bug #13406)

   * A server crash could occur if a prepared statement updated a table
     for which a trigger existed when the statement was prepared but
     had been dropped prior to statement execution.  (Bug #13399)

   * *Note `RESET MASTER': reset-master. failed to delete log files on
     Windows. One consequence of this change is that server opens the
     general query and slow log files in shared mode, so now they can
     be renamed while the server has them open (something not true in
     previous versions).  (Bug #13377)

   * For binary string data types, *Note `mysqldump --hex-blob':
     mysqldump. produced an illegal output value of `0x' rather than
     `'''.  (Bug #13318)

   * *Note `REPAIR TABLE': repair-table, *Note `BACKUP TABLE':
     backup-table, *Note `RESTORE TABLE': restore-table. within a stored
     procedure caused a server crash.  (Bug #13012)

   * Implicit versus explicit conversion of float to integer (such as
     inserting a float value into an integer column versus using
     `CAST(... AS UNSIGNED)' before inserting the value) could produce
     different results. Implicit and explicit typecasts now are done
     the same way, with a value equal to the nearest integer according
     to the prevailing rounding mode.  (Bug #12956)

   * Some comparisons for the `IN()' operator were inconsistent with
     equivalent comparisons for the `=' operator.  (Bug #12612)

   * A server crash could occur if a prepared statement invoked a
     stored procedure that existed when the statement was prepared but
     had been dropped and re-created prior to statement execution.
     (Bug #12329)

   * `make' failed when attempting to build MySQL in different
     directory other than that containing the source.  (Bug #11827)

   * Revised table locking to permit proper assessment of view security.
     (Bug #11555)

   * Perform character set conversion of constant values whenever
     possible without data loss.  (Bug #10446)

   * Within a trigger definition the `CURRENT_USER()' function evaluated
     to the user whose actions caused the trigger to be activated.  Now
     that triggers have a `DEFINER' value, `CURRENT_USER()' evaluates
     to the trigger definer.  (Bug #5861)

   * *Note `mysql': mysql. ignored the `MYSQL_TCP_PORT' environment
     variable.  (Bug #5792)


File: manual.info,  Node: news-5-0-16,  Next: news-5-0-15,  Prev: news-5-0-17,  Up: news-5-0-x

D.1.81 Changes in MySQL 5.0.16 (10 November 2005)
-------------------------------------------------

*Functionality Added or Changed*

   * *MySQL Cluster*: The `InnoDB', *Note `NDB': mysql-cluster, `BDB',
     and `ARCHIVE' storage engines now support spatial columns. See
     *Note spatial-extensions::.

   * *Replication*: Added a `--hexdump' option to *Note `mysqlbinlog':
     mysqlbinlog. that displays a hex dump of the log in comments. This
     output can be helpful for replication debugging.

   * When a date column is set `NOT NULL' and contains `0000-00-00', it
     will be updated for UPDATE statements that contains ` COLUMNNAME
     IS NULL' in the WHERE clause.  (Bug #14186)

   * When trying to run the server with yaSSL enabled, MySQL now tries
     to open `/dev/random' automatically if `/dev/urandom' is not
     available.  (Bug #13164)

   * MySQL 5.0 now supports character set conversion for seven
     additional `cp950' characters into the `big5' character set:
     `0xF9D6', `0xF9D7', `0xF9D8', `0xF9D9', `0xF9DA', `0xF9DB', and
     `0xF9DC'.

     *Note*:

     If you move data containing these additional characters to an
     older MySQL installation which does not support them, you may
     encounter errors.

     (Bug #12476)

   * You must now declare a prefix for an index on any column of any
     `Geometry' class, the only exception being when the column is a
     `POINT'.  (Bug #12267)

   * The `read_only' system variable no longer applies to `TEMPORARY'
     tables.  (Bug #4544)

   * Due to changes in binary logging, the restrictions on which stored
     routine creators can be trusted not to create unsafe routines have
     been lifted for stored procedures (but not stored functions).
     Consequently, the `log_bin_trust_routine_creators' system variable
     and the corresponding `--log-bin-trust-routine-creators' server
     option were renamed to `log_bin_trust_function_creators' and
     `--log-bin-trust-function-creators'. For backward compatibility,
     the old names are recognized but result in a warning. See *Note
     stored-programs-logging::.

   * The *Note `CHECK TABLE': check-table. statement now works for
     `ARCHIVE' tables.

   * In MySQL 5.0.13, syntax for `DEFINER' and `SQL SECURITY' clauses
     was added to the *Note `CREATE VIEW': create-view. and *Note
     `ALTER VIEW': alter-view. statements, but the clauses had no
     effect. They now are enabled. They specify the security context to
     be used when checking access privileges at view invocation time.
     See *Note create-view::, for more information.

   * Added the `Compression' status variable, which indicates whether
     the client connection uses compression in the client/server
     protocol.

*Bugs Fixed*

   * *MySQL Cluster*: Repeated transactions using unique index lookups
     could cause a memory leak leading to error 288, `Out of index
     operations in transaction coordinator'.  (Bug #14199)

   * *MySQL Cluster*: A memory leak occurred when performing ordered
     index scans using indexes on columns larger than 32 bytes. This
     would eventually lead to the forced shutdown of all *Note
     `mysqld': mysqld.  server processes used with the cluster.  (Bug
     #13078)

   * For some stored functions dumped by *Note `mysqldump --routines':
     mysqldump, the function definition could not be reloaded later due
     to a parsing error.  (Bug #14723)

   * Deletes from a `CSV' table could cause table corruption.  (Bug
     #14672)

   * Executing *Note `REPAIR TABLE': repair-table, *Note `ANALYZE
     TABLE': analyze-table, or *Note `OPTIMIZE TABLE': optimize-table.
     on a view for which an underlying table had been dropped caused a
     server crash.  (Bug #14540)

   * `mysqlmanager' did not start up correctly on Windows 2003.  (Bug
     #14537)

   * Selecting from a table in both an outer query and a subquery could
     cause a server crash.  (Bug #14482)

   * `ORDER BY DESC' within the `GROUP_CONCAT()' function was not
     honored when used in a view.  (Bug #14466)

   * The input polling loop for Instance Manager did not sleep
     properly. Instance Manager used up too much CPU as a result.  (Bug
     #14388)

   * Indexes for `BDB' tables were being limited incorrectly to 255
     bytes.  (Bug #14381)

   * The *Note `mysql': mysql. parser did not properly strip the
     delimiter from input lines less than nine characters long. For
     example, this could cause `USE abc;' to result in an `Unknown
     database: abc;' error.  (Bug #14358)

   * The displayed value for the `CHARACTER_MAXIMUM_LENGTH' column in
     the *Note `INFORMATION_SCHEMA.COLUMNS': columns-table. table was
     not adjusted for multi-byte character sets.  (Bug #14290)

   * The parser did not correctly recognize wildcards in the host part
     of the `DEFINER' user in *Note `CREATE VIEW': create-view.
     statements.  (Bug #14256)

   * Memory corruption and a server crash could be caused by statements
     that used a cursor and generated a result set larger than
     `max_heap_table_size'.  (Bug #14210)

   * A bug fix in MySQL 5.0.15 caused the displayed values for the
     `CHARACTER_MAXIMUM_LENGTH' and `CHARACTER_OCTET_LENGTH' columns in
     the *Note `INFORMATION_SCHEMA.COLUMNS': columns-table. table to be
     reversed.  (Bug #14207)

   * Statements of the form *Note `CREATE TABLE ... SELECT ...':
     create-table. that created a column with a multi-byte character
     set could incorrectly calculate the maximum length of the column,
     resulting in a `Specified key was too long' error.  (Bug #14139)

   * Use of `WITH ROLLUP PROCEDURE ANALYSE()' could hang the server.
     (Bug #14138)

   * On Windows, the value of `character_sets_dir' in *Note `SHOW
     VARIABLES': show-variables. output was displayed inconsistently
     (using both ``/'' and ``\'' as path name component separators).
     (Bug #14137)

   * A comparison with an invalid date (such as `WHERE COL_NAME >
     '2005-09-31'') caused any index on COL_NAME not to be used and a
     string comparison for each row, resulting in slow performance.
     (Bug #14093)

   * Subqueries in the `FROM' clause failed if the current database was
     `INFORMATION_SCHEMA'.  (Bug #14089)

   * For `InnoDB' tables, using a column prefix for a `utf8' column in
     a primary key caused `Cannot find record' errors when attempting to
     locate records.  (Bug #14056)

   * Some updatable views could not be updated.  (Bug #14027)

   * A prepared statement that selected from a view processed using the
     merge algorithm could crash on the second execution.  (Bug #14026)

   * When the `DATE_FORMAT()' function appeared in both the *Note
     `SELECT': select. and `ORDER BY' clauses of a query but with
     arguments that differ by case (for example, `%m' and `%M'),
     incorrect sorting may have occurred.  (Bug #14016)

   * `TIMEDIFF()', `ADDTIME()', and `STR_TO_DATE()' were not reporting
     that they could return `NULL', so functions that invoked them
     might misinterpret their results.  (Bug #14009)

   * Within stored routines, `REPLACE()' could return an empty string
     (rather than the original string) when no replacement was done, and
     `IFNULL()' could return garbage results.  (Bug #13941)

   * Inserting a new row into an `InnoDB' table could cause *Note
     `DATETIME': datetime. values already stored in the table to change.
     (Bug #13900)

   * An update of a `CSV' table could cause a server crash.  (Bug
     #13894)

   * Corrected a parser precedence problem that resulted in an `Unknown
     column ... in 'on clause'' error for some joins.  (Bug #13832)

   * Trying to take the logarithm of a negative value is now handled in
     the same fashion as division by zero. That is, it produces a
     warning when `ERROR_FOR_DIVISION_BY_ZERO' is set, and an error in
     strict mode.  (Bug #13820)

   * The example configuration files supplied with MySQL distributions
     listed the `thread_cache_size' variable as `thread_cache'.  (Bug
     #13811)

   * *Note `mysqld_safe': mysqld-safe. did not correctly start the
     `-max' version of the server (if it was present) if the `--ledir'
     option was given.  (Bug #13774)

   * *Note `SHOW CREATE TABLE': show-create-table. did not display the
     `CONNECTION' string for `FEDERATED' tables.  (Bug #13724)

   * For a `MyISAM' table originally created in MySQL 4.1, *Note
     `INSERT DELAYED': insert-delayed. could cause a server crash.
     (Bug #13707)

   * The server incorrectly accepted column definitions of the form
     `DECIMAL(0,D)' for D less than 11.  (Bug #13667)

   * Trying to create a stored routine with no database selected would
     crash the server.  (Bug #13587, Bug #13514)

   * Inserts of too-large *Note `DECIMAL': numeric-types.  values were
     handled inconsistently (sometimes set to the maximum *Note
     `DECIMAL': numeric-types. value, sometimes set to 0).  (Bug #13573)

   * `TIMESTAMPDIFF()' returned an incorrect result if one argument but
     not the other was a leap year and a date was from March or later.
     (Bug #13534)

   * Specifying `--default-character-set=cp-932' for *Note `mysqld':
     mysqld. would cause SQL scripts containing comments written using
     that character set to fail with a syntax error.  (Bug #13487)

   * Use of `COL_NAME = VALUES(COL_NAME)' in the `ON DUPLICATE KEY
     UPDATE' clause of an *Note `INSERT': insert. statement failed with
     an `Column 'COL_NAME' in field list is ambiguous' error.  (Bug
     #13392)

   * The default value of `query_prealloc_size' was set to 8192, lower
     than its minimum of 16384. The minimum has been lowered to 8192.
     (Bug #13334)

   * `InnoDB': When dropping and adding a `PRIMARY KEY', if a loose
     index scan using only the second part of multiple-part index was
     chosen, incorrect keys were created and an endless loop resulted.
     (Bug #13293)

   * *Note `mysqladmin': mysqladmin. and *Note `mysqldump': mysqldump.
     would hang on SCO OpenServer.  (Bug #13238)

   * `SELECT DISTINCT CHAR(COL_NAME)' returned incorrect results after
     `SET NAMES utf8'.  (Bug #13233)

   * For queries with nested outer joins, the optimizer could choose
     join orders that query execution could not handle. The fix is that
     now the optimizer avoids choosing such join orders.  (Bug #13126)

   * The server did not take character set into account in checking the
     width of the `mysql.user.Password' column.  As a result, it could
     incorrectly generate long password hashes even if the column was
     not long enough to hold them.  (Bug #13064)

   * The source distribution failed to compile when configured with the
     `--without-geometry' option.  (Bug #12991)

   * Use of the deprecated `--sql-bin-update-same' option caused a
     server crash.  (Bug #12974)

   * Maximum values were handled incorrectly for command-line options
     of type `GET_LL'.  (Bug #12925)

   * *Note `mysqldump': mysqldump. could not dump views if the `-x'
     option was given.  (Bug #12838)

   * Two threads that were creating triggers on an `InnoDB' table at
     the same time could deadlock.  (Bug #12739)

   * `InnoDB': Large `innobase_buffer_pool_size' and
     `innobase_log_file_size' values were displayed incorrectly on
     64-bit systems.  (Bug #12701)

   * For `LIKE ... ESCAPE', an escape sequence longer than one
     character was accepted as valid. Now the sequence must be empty or
     one character long. If the `NO_BACKSLASH_ESCAPES' SQL mode is
     enabled, the sequence must be one character long.  (Bug #12595)

   * Inserting `cp932' strings into a *Note `VARCHAR': char. column
     caused a server crash rather than string truncation if the string
     was longer than the column definition.  (Bug #12547)

   * A prepared statement failed with `Illegal mix of collations' if
     the client character set was `utf8' and the statement used a table
     that had a character set of `latin1'.  (Bug #12371)

   * Using *Note `ALTER TABLE': alter-table. to add an index could fail
     if the operation ran out of temporary file space. Now it
     automatically makes a second attempt that uses a slower method but
     no temporary file. In this case, problems that occurred during the
     first attempt can be displayed with *Note `SHOW WARNINGS':
     show-warnings.  (Bug #12166)

   * *Note `mysqlimport': mysqlimport. now issues a `SET
     @@character_set_database = binary' statement before loading data
     so that a file containing mixed character sets (columns with
     different character sets) can be loaded properly.  (Bug #12123)

   * Running *Note `OPTIMIZE TABLE': optimize-table. and other
     data-updating statements concurrently on an `InnoDB' table could
     cause a crash or the following warnings in the error log:
     `Warning: Found locks from different threads in write: enter
     write_lock', `Warning: Found locks from different threads in
     write: start of release lock'.  (Bug #11704)

   * *Note `LOAD DATA INFILE': load-data. would not accept the same
     character for both the `ESCAPED BY' and the `ENCLOSED BY' clauses.
     (Bug #11203)

   * The value of `Last_query_cost' was not updated for queries served
     from the query cache.  (Bug #10303)

   * Starting *Note `mysqld': mysqld. with the `--skip-innodb' and
     `--default-storage-engine=innodb' (or `--default-table-type=innodb'
     caused a server crash.  (Bug #9815)

   * The `--exit-info=65536' option conflicted with `--temp-pool' and
     caused problems with the server's use of temporary files. Now
     `--temp-pool' is ignored if `--exit-info=65536' is specified.
     (Bug #9551)

   * For a user that has the *Note `SELECT': select.  privilege on a
     view, the server erroneously was also requiring the user to have
     the `EXECUTE' privilege at view execution time for stored
     functions used in the view definition.  (Bug #9505)

   * Where one stored procedure called another stored procedure: If the
     second stored procedure generated an exception, the exception was
     not caught by the calling stored procedure. For example, if stored
     procedure `A' used an `EXIT' statement to handle an exception,
     subsequent statements in `A' would be executed regardless when `A'
     was called by another stored procedure `B', even if an exception
     that should have been handled by the `EXIT' was generated in `A'.
     (Bug #7049)

   * On Windows, the server was not ignoring hidden or system
     directories that Windows may have created in the data directory,
     and would treat them as available databases.  (Bug #4375)


File: manual.info,  Node: news-5-0-15,  Next: news-5-0-14,  Prev: news-5-0-16,  Up: news-5-0-x

D.1.82 Changes in MySQL 5.0.15 (19 October 2005 Production)
-----------------------------------------------------------

*Functionality Added or Changed*

   * *Incompatible Change*: For *Note `BINARY': binary-varbinary.
     columns, the pad value and how it is handled has changed. The pad
     value for inserts now is `0x00' rather than space, and there is no
     stripping of the pad value for selects. For details, see *Note
     binary-varbinary::.

   * *Incompatible Change*: The `CHAR()' function now returns a binary
     string rather than a string in the connection character set. An
     optional `USING CHARSET' clause may be used to produce a result in
     a specific character set instead. Also, arguments larger than 256
     produce multiple characters. They are no longer interpreted modulo
     256 to produce a single character each. These changes may cause
     some incompatibilities, as noted in *Note
     upgrading-from-previous-series::.

   * *MySQL Cluster*: The *Note `ndb_mgm':
     mysql-cluster-programs-ndb-mgm. client now reports node startup
     phases automatically.  (Bug #16197)

   * *MySQL Cluster*: A new `smart' node allocation algorithm means that
     it is no longer necessary to use sequential IDs for cluster nodes,
     and that nodes not explicitly assigned IDs should now have IDs
     allocated automatically in most cases. In practical terms, this
     means that it is now possible to assign a set of node IDs such as
     `1', `2', `4', `5' without an error being generated due to the
     missing `3'.  (Bug #13009)

   * *MySQL Cluster*: A number of new or improved error messages have
     been implemented in this release to provide better and more
     accurate diagnostic information regarding cluster configuration
     issues and problems.  (Bug #12786, Bug #11749, Bug #13197, Bug
     #11739, Bug #12044)

   * The following statements now cause an implicit *Note `COMMIT':
     commit.:

        * *Note `CREATE VIEW': create-view.

        * *Note `ALTER VIEW': alter-view.

        * *Note `DROP VIEW': drop-view.

        * *Note `CREATE TRIGGER': create-trigger.

        * *Note `DROP TRIGGER': drop-trigger.

        * *Note `CREATE USER': create-user.

        * *Note `RENAME USER': rename-user.

        * *Note `DROP USER': drop-user.

     (Bug #13343)

   * Added the `--tz-utc' option to *Note `mysqldump': mysqldump. This
     option adds `SET TIME_ZONE='+00:00'' to the dump file so that
     *Note `TIMESTAMP': datetime. columns can be dumped and reloaded
     between servers in different time zones and protected from changes
     due to daylight saving time.  (Bug #13052)

   * When executing single-table *Note `UPDATE': update. or *Note
     `DELETE': delete. queries containing an `ORDER BY ... LIMIT N'
     clause, but not having any `WHERE' clause, MySQL can now take
     advantage of an index to read the first N rows in the ordering
     specified in the query. If an index is used, only the first N
     records will be read, as opposed to scanning the entire table.
     (Bug #12915)

   * The `MySQL-server' RPM now explicitly assigns the `mysql' system
     user to the `mysql' user group during the postinstallation
     process. This corrects an issue with upgrading the server on some
     Linux distributions whereby a previously existing `mysql' user was
     not changed to the `mysql' group, resulting in wrong groups for
     files created following the installation.  (Bug #12823)

   * The maximum key length for `InnoDB' indexes was increased from
     1024 bytes to 3072 bytes for 64-bit builds.

   * When declaring a local variable (or parameter) named `password' or
     `name', and setting it with *Note `SET': set-option. (for example,
     `SET password = '''), the new error message `ERROR 42000: Variable
     'nnn' must be quoted with `...`, or renamed' is returned (where
     'nnn' is 'password' or 'names'). This means there is a syntax
     conflict with special sentences like `SET PASSWORD =
     PASSWORD(...)' (for setting a user's password) and `set names
     default' (for setting charset and collation).

     This must be resolved either by quoting the variable name: `SET
     `password` = ...', which will set the local variable ``password`',
     or by renaming the variable to something else (if setting the
     user's password is the desired effect).

*Bugs Fixed*

   * *MySQL Cluster*: The *Note `perror': perror. utility included with
     the `MySQL-Server' RPM did not provide support for the `--ndb'
     option. It now supports this option, and so can be used to obtain
     error message text for MySQL Cluster error codes.  (Bug #13740)

   * *MySQL Cluster*: Placing multiple `[tcp default]' sections in the
     cluster's `config.ini' file crashed *Note `ndb_mgmd':
     mysql-cluster-programs-ndb-mgmd. (The process now exits gracefully
     in such cases, with an appropriate error message.)  (Bug #13611)

   * *MySQL Cluster*: *Note `ndb_mgmd':
     mysql-cluster-programs-ndb-mgmd. permitted a node to be stopped or
     restarted while another node was still starting up, which could
     crash the cluster. It should now not be possible to issue a node
     stop or restart while a different node is still restarting, and
     the cluster management client should issue an error when such an
     attempt is made.  (Bug #13461)

   * *MySQL Cluster*: Trying to run *Note `ndbd':
     mysql-cluster-programs-ndbd. as system `root' when connecting to a
     *Note `mysqld': mysqld. process running as the `mysql' system user
     using SHM caused the *Note `ndbd': mysql-cluster-programs-ndbd.
     process to crash.  (*Note `ndbd': mysql-cluster-programs-ndbd.
     should now exit gracefully with an appropriate error message
     instead.)  (Bug #9249)

   * *Replication*: An *Note `UPDATE': update. query using a join would
     be executed incorrectly on a replication slave.  (Bug #12618)

   * Tests containing *Note `SHOW TABLE STATUS': show-table-status. or
     `INFORMATION_SCHEMA' failed on opnsrv6c.  (Bug #14064, Bug #14065)

   * *Note `mysqldump': mysqldump. could not dump views.  (Bug #14061)

   * *Note `mysqlcheck': mysqlcheck.  `--all-databases' `--analyze'
     `--optimize' failed because it also tried to analyze and optimize
     the `INFORMATION_SCHEMA' tables which it can't.  (Bug #13783)

   * Character set conversion was not being done for `FIND_IN_SET()'.
     (Bug #13751)

   * On BSD systems, the system `crypt()' call could return an error
     for some salt values. The error was not handled, resulting in a
     server crash.  (Bug #13619)

   * When calling a stored procedure with the syntax `CALL
     SCHEMA.PROCEDURENAME ' and no default schema selected, `ERROR
     1046' was displayed after the procedure returned.  (Bug #13616)

   * A column in the `ON' condition of a join that referenced a table
     in a nested join could not be resolved if the nested join was a
     right join.  (Bug #13597)

   * The server could over-allocate memory when performing a `FULLTEXT'
     search for stopwords only.  (Bug #13582)

   * `CREATE DEFINER=... VIEW ...' caused the server to crash when run
     with `--skip-grant-tables'.  (Bug #13504)

   * `InnoDB': Queries that were executed using an `index_merge' union
     or intersection could produce incorrect results if the underlying
     table used the `InnoDB' storage engine and had a primary key
     containing *Note `VARCHAR': char.  members.  (Bug #13484)

   * A qualified reference to a view column in the `HAVING' clause
     could not be resolved.  (Bug #13410)

   * `CAST(1E+300 TO SIGNED INT)' produced an incorrect result on
     little-endian machines.  (Bug #13344)

   * Queries that use indexes in normal *Note `SELECT': select.
     statements may cause range scans in `VIEW's.  (Bug #13327)

   * `SELECT * INTO OUTFILE ... FROM INFORMATION_SCHEMA.schemata'
     failed with an `Access denied' error.  (Bug #13202)

   * *Note `mysqldump --triggers': mysqldump. did not quote identifiers
     properly if the `--compatible' option was given, so the dump
     output could not be reloaded.  (Bug #13146)

   * A table or view named Ç (C-cedilla) couldn't be dropped.  (Bug
     #13145)

   * For XA transaction IDs (` GTRID.BQUAL.FORMATID '), uniqueness is
     supposed to be assessed based on GTRID and BQUAL. MySQL was also
     including FORMATID in the uniqueness check.  (Bug #13143)

   * Trying to create a view dynamically using a prepared statement
     within a stored procedure failed with error 1295.  (Bug #13095)

   * *Note `comp_err': comp-err. did not detect when multiple error
     messages for a language were given for an error symbol.  (Bug
     #13071)

   * If special characters such as `'_'' , `'%'', or the escape
     character were included within the prefix of a column index, `LIKE'
     pattern matching on the indexed column did not return the correct
     result.  (Bug #13046, Bug #13919)

   * Using an undefined variable in an *Note `IF': if-statement. or
     *Note `SET': set-option.  statement inside a stored routine
     produced an incorrect `unknown column ... in 'order clause'' error
     message.  (Bug #13037)

   * With `--log-slave-updates' `Exec_master_log_pos' of SQL thread
     lagged IO (Bug #13023)

   * *Note `SHOW CREATE TABLE': show-create-table. did not display any
     `FOREIGN KEY' clauses if a temporary file could not be created.
     Now *Note `SHOW CREATE TABLE': show-create-table. displays an
     error message in an SQL comment if this occurs.  (Bug #13002)

   * Local (non-XA) and XA transactions are supposed to be mutually
     exclusive within a given client connection, but this prohibition
     was not always enforced.  (Bug #12935)

   * Server crashed during a *Note `SELECT': select.  statement,
     writing a message like this to the error log:

          `InnoDB': Error: MySQL is trying to perform a SELECT
          `InnoDB': but it has not locked any tables in ::external_lock()!

     (Bug #12736)

   * An expression in an `ORDER BY' clause failed with `Unknown column
     'COL_NAME' in 'order clause'' if the expression referred to a
     column alias.  (Bug #11694)

   * Issuing *Note `STOP SLAVE': stop-slave. after having acquired a
     global read lock with *Note `FLUSH TABLES WITH READ LOCK': flush.
     caused a deadlock. Now *Note `STOP SLAVE': stop-slave. is
     generates an error in such circumstances.  (Bug #10942)

   * Corrected a memory-copying problem for `big5' values when using
     `icc' compiler on Linux IA-64 systems.  (Bug #10836)

   * The `--interactive-timeout' and `--slave-net-timeout' options for
     *Note `mysqld': mysqld. were not being obeyed on Mac OS X and
     other BSD-based platforms.  (Bug #8731)

   * Queries of the form `(SELECT ...) ORDER BY ...' were being treated
     as a *Note `UNION': union.  This improperly resulted in only
     distinct values being returned (because *Note `UNION': union. by
     default eliminates duplicate results). Also, references to column
     aliases in `ORDER BY' clauses following parenthesized *Note
     `SELECT': select. statements were not resolved properly.  (Bug
     #7672)

   * Character set file parsing during *Note `mysql_real_connect()':
     mysql-real-connect. read past the end of a memory buffer.  (Bug
     #6413)


File: manual.info,  Node: news-5-0-14,  Next: news-5-0-13,  Prev: news-5-0-15,  Up: news-5-0-x

D.1.83 Changes in MySQL 5.0.14 (Not released)
---------------------------------------------

*Functionality Added or Changed*

   * *Replication*: Multiple-table *Note `UPDATE': update. and *Note
     `DELETE': delete. statements that do not affect any rows are now
     written to the binary log and will replicate.  (Bug #13348, Bug
     #12844)

   * Range scans can now be performed for queries on VIEWs such as
     `column IN (<constants>)' and `column BETWEEN ConstantA AND
     ConstantB'.  (Bug #13317)

   * The limit of 255 characters on the input buffer for *Note `mysql':
     mysql. on Windows has been lifted. The exact limit depends on what
     the system permits, but can be up to 64KB characters. A typical
     limit is 16KB characters.  (Bug #12929)

   * Added the `myisam_stats_method', which controls whether `NULL'
     values in indexes are considered the same or different when
     collecting statistics for `MyISAM' tables. This influences the
     query optimizer as described in *Note myisam-index-statistics::.
     (Bug #12232)

   * The `CHAR()' function now takes into account the character set and
     collation given by the `character_set_connection' and
     `collation_connection' system variables. For an argument N to
     `CHAR()', the result is N mod 256 for single-byte character sets.
     For multi-byte character sets, N must be a valid code point in the
     character set. Also, the result string from `CHAR()' is checked for
     well-formedness. For invalid arguments, or a result that is not
     well-formed, MySQL generates a warning (or, in strict SQL mode, an
     error).  (Bug #10504)

   * Re-enabled the `--delayed-insert' option for *Note `mysqldump':
     mysqldump, which now checks for each table dumped whether its
     storage engine supports `DELAYED' inserts.  (Bug #7815)

   * *Note `RENAME TABLE': rename-table. now works for views as well,
     as long as you do not try to rename a view into a different
     database.  (Bug #5508)

   * Configure-time checking for the availability of multi-byte macros
     and functions in the bundled `readline' library. This improves
     handling of multi-byte character sets in the *Note `mysql': mysql.
     client.  (Bug #3982)

   * When an `InnoDB' foreign key constraint is violated, the error
     message now indicates which table, column, and constraint names
     are involved.  (Bug #3443)

*Bugs Fixed*

   * *MySQL Cluster*: A trigger updating the value of an
     `AUTO_INCREMENT' column in an *Note `NDB': mysql-cluster. table
     would insert an error code rather than the expected value into the
     column.  (Bug #13961)

   * *MySQL Cluster*: If *Note `ndb_restore':
     mysql-cluster-programs-ndb-restore. could not find a free *Note
     `mysqld': mysqld. process, it crashed.  (Bug #13512)

   * *MySQL Cluster*: Adding an index to a table with a large number of
     columns (more then 100) crashed the storage node.  (Bug #13316)

   * *MySQL Cluster*: *Note `BIT': numeric-types. columns and following
     columns in *Note `NDB': mysql-cluster. tables were corrupt when
     dumped by *Note `mysqldump': mysqldump.  (Bug #13152)

   * *MySQL Cluster*: Queries on *Note `NDB': mysql-cluster. tables
     that were executed using `index_merge' could produce incorrect
     results.  (Bug #13081)

   * *MySQL Cluster*: Receipt of several `ENTER SINGLE USER MODE'
     commands by multiple *Note `ndb_mgmd':
     mysql-cluster-programs-ndb-mgmd. processes within a short period
     of time resulted in cluster shutdown.  (Bug #13053)

   * *MySQL Cluster*: Multiple *Note `ndb_mgmd':
     mysql-cluster-programs-ndb-mgmd. processes in a cluster did not
     know each other's IP addresses.  (Bug #12037)

   * *MySQL Cluster*: With two `mgmd' processes in a cluster, *Note
     `ndb_mgm': mysql-cluster-programs-ndb-mgm. output for *Note
     `SHOW': show. would display the same IP address for both
     processes, even when they were on different hosts.  (Bug #11595)

   * *MySQL Cluster*: *Note `LOAD DATA INFILE': load-data. with a large
     data file failed.  (Bug #10694)

   * *MySQL Cluster*: When deleting a great many (tens of thousands of)
     rows at once from an *Note `NDB': mysql-cluster. table, an
     improperly dereferenced pointer could cause the *Note `mysqld':
     mysqld.  process to crash.  (Bug #9282)

   * *Replication*: The `--replicate-rewrite-db' and
     `--replicate-do-table' options did not work for statements in
     which tables were aliased to names other than those listed by the
     options.  (Bug #11139)

   * Certain joins using `Range checked for each record' in the query
     execution plan could cause the server to crash.  (Bug #24776)

   * Joins nested under `NATURAL' or `USING' joins were sometimes not
     initialized properly, causing a server crash.  (Bug #13545)

   * After running `configure' with the
     `--with-embedded-privilege-control' option, the embedded server
     failed to build.  (Bug #13501)

   * The optimizer chose a less efficient execution plan for `COL_NAME
     BETWEEN CONST AND CONST' than for ` COL_NAME = CONST', even though
     the two expressions are logically equivalent. Now the optimizer
     can use the `ref' access method for both expressions.  (Bug #13455)

   * Locking a view with the query cache enabled and
     `query_cache_wlock_invalidate' enabled could cause a server crash.
     (Bug #13424)

   * A `HAVING' clause that references an unqualified view column name
     could crash the server.  (Bug #13411)

   * The `--skip-innodb-doublewrite' option disables use of the
     `InnoDB' doublewrite buffer.  However, having this option in
     effect when creating a new MySQL installation prevented the buffer
     from even being created, resulting in a server crash later.  (Bug
     #13367)

   * Calling the `FORMAT()' function with a *Note `DECIMAL':
     numeric-types. column value caused a server crash when the value
     was `NULL'.  (Bug #13361)

   * Comparisons involving row constructors containing constants could
     cause a server crash.  (Bug #13356)

   * Aggregate functions sometimes incorrectly were permitted in the
     `WHERE' clause of *Note `UPDATE': update. and *Note `DELETE':
     delete. statements.  (Bug #13180)

   * `NATURAL' joins and joins with `USING' against a view could return
     `NULL' rather than the correct value.  (Bug #13127)

   * For queries with `DISTINCT' and `WITH ROLLUP', the `DISTINCT'
     should be applied after the rollup operation, but was not always.
     (Bug #12887)

   * It was possible to create a view that executed a stored function
     for which you did not have the `EXECUTE' privilege.  (Bug #12812)

   * Shared-memory connections were not working on Windows.  (Bug
     #12723)

   * The server was not rejecting `FLOAT(M,D)' or `DOUBLE(M,D)' columns
     specifications when M was less than D.  (Bug #12694)

   * *Note `CHECKSUM TABLE': checksum-table. locked `InnoDB' tables and
     did not use a consistent read.  (Bug #12669)

   * Incorrect creation of *Note `DECIMAL': numeric-types.  local
     variables in a stored procedure could cause a server crash.  (Bug
     #12589)

   * For queries for which the optimizer determined a join type of
     `Range checked for each record' (as shown by *Note `EXPLAIN':
     explain, the query sometimes could cause a server crash, depending
     on the data distribution.  (Bug #12291)

   * After running `configure' with the `--without-server' option, the
     distribution failed to build.  (Bug #11680, Bug #13550)

   * Use of a user-defined function within the `HAVING' clause of a
     query resulted in an `Unknown column' error.  (Bug #11553)

   * The server crashed when processing a view that invoked the
     `CONVERT_TZ()' function.  (Bug #11416)

   * When *Note `SELECT ... FOR UPDATE': select. or *Note `SELECT ...
     LOCK IN SHARE MODE': select. for an `InnoDB' table were executed
     from within a stored function or a trigger, they were converted to
     a nonlocking consistent read.  (Bug #11238)

   * Queries against a `MERGE' table that has a composite index could
     produce incorrect results.  (Bug #9112)

   * MySQL programs in binary distributions for Solaris 8/9/10 x86
     systems would not run on Pentium III machines.  (Bug #6772)

   * Nested handlers within stored procedures didn't work.  (Bug #6127)


File: manual.info,  Node: news-5-0-13,  Next: news-5-0-12,  Prev: news-5-0-14,  Up: news-5-0-x

D.1.84 Changes in MySQL 5.0.13 (22 September 2005 Release Candidate)
--------------------------------------------------------------------

*Functionality Added or Changed*

   * *Replication*: Better detection of connection timeout for
     replication servers on Windows enables elimination of extraneous
     `Lost connection' errors in the error log.  (Bug #5588)

   * *Note `OPTIMIZE TABLE': optimize-table. and *Note `HANDLER':
     handler. now are prohibited in stored procedures and functions and
     in triggers.  (Bug #12953, Bug #12995)

   * The `LEAST()' and `GREATEST()' functions used to return `NULL'
     only if all arguments were `NULL'. Now they return `NULL' if any
     argument is `NULL', the same as Oracle.  (Bug #12791)

   * `InnoDB': The *Note `TRUNCATE TABLE': truncate-table. statement
     for `InnoDB' tables always resets the counter for an
     `AUTO_INCREMENT' column now, regardless of whether there is a
     foreign key constraint on the table.  (Beginning with 5.0.3, *Note
     `TRUNCATE TABLE': truncate-table. reset the counter, but only if
     there was no such constraint.)  (Bug #11946)

   * Reorder network startup to come after all other initialization,
     particularly storage engine startup which can take a long time.
     This also prevents MySQL from being run on a privileged port (any
     port under 1024) unless run as the root user.  (Bug #11707)

   * The restriction on the use of *Note `PREPARE': prepare, *Note
     `EXECUTE': execute, and *Note `DEALLOCATE PREPARE':
     deallocate-prepare. within stored procedures was lifted. The
     restriction still applies to stored functions and triggers.  (Bug
     #10975, Bug #10605) See also Bug #7115.

   * A new command line argument was added to *Note `mysqld': mysqld.
     to ignore client character set information sent during handshake,
     and use server side settings instead, to reproduce 4.0 behavior :

          mysqld --skip-character-set-client-handshake

     (Bug #9948)

   * Added a `--routines' option for *Note `mysqldump': mysqldump. that
     enables dumping of stored routines.  (Bug #9056)

   * `RAND()' no longer permits nonconstant initializers. (Previously,
     the effect of nonconstant initializers is undefined.)  (Bug #6172)

   * The syntax for *Note `CREATE VIEW': create-view. and *Note `ALTER
     VIEW': alter-view. statements now includes `DEFINER' and `SQL
     SECURITY' clauses for specifying the security context to be used
     when checking access privileges at view invocation time. (The
     syntax is present in 5.0.13, but these clauses have no effect
     until 5.0.16.) See *Note create-view::, for more information.

   * The `--hex-dump' option for *Note `mysqldump': mysqldump. now also
     applies to *Note `BIT': numeric-types. columns.

   * Two new collations have been added for Esperanto:
     `utf8_esperanto_ci' and `ucs2_esperanto_ci'.

   * The Windows binary packages are now compiled with the Microsoft
     Visual Studio 2003 compiler instead of Microsoft Visual C++ 6.0.

   * The connection string for `FEDERATED' tables now is specified
     using a `CONNECTION' table option rather than a `COMMENT' table
     option.

   * The binaries compiled with the Intel icc compiler are now built
     using icc 9.0 instead of icc 8.1. You will have to install new
     versions of the Intel icc runtime libraries, which are available
     from here: `http://dev.mysql.com/downloads/os-linux.html'

*Bugs Fixed*

   * *Incompatible Change*: A lock wait timeout caused `InnoDB' to roll
     back the entire current transaction. Now it rolls back only the
     most recent SQL statement.  (Bug #12308)

   * *MySQL Cluster*: The cluster management client `START BACKUP'
     command could be interrupted by a *Note `SHOW': show. command.
     (Bug #13054)

   * *MySQL Cluster*: A cluster shutdown following the crash of a data
     node failed to terminate any remaining node processes, even though
     *Note `ndb_mgm': mysql-cluster-programs-ndb-mgm. showed the
     shutdown request as having been completed.  (Bug #9996, Bug
     #10938, Bug #11623)

   * *MySQL Cluster*: The average row size for Cluster tables was
     calculated incorrectly. This affected the values shown for the
     `Data_length' and `Avg_row_length' columns in the output generated
     by *Note `SHOW TABLE STATUS': show-table-status. as well as the
     values for the `data_length' and `data_length/table_rows' columns
     shown in the *Note `TABLES': tables-table. table of the
     `INFORMATION_SCHEMA' database with respect to Cluster tables.

     Tables using storage engines other than *Note `NDB':
     mysql-cluster. were not affected by this bug.  (Bug #9896)

   * *Replication*: Within a transaction, the following statements now
     cause an implicit commit: *Note `CREATE FUNCTION': create-function,
     *Note `DROP FUNCTION': drop-function, *Note `DROP PROCEDURE':
     drop-procedure. (for stored functions, not UDFs), *Note `ALTER
     FUNCTION': alter-function, *Note `ALTER PROCEDURE':
     alter-procedure, *Note `CREATE PROCEDURE': create-procedure. This
     corrects a problem where these statements followed by *Note
     `ROLLBACK': commit. might not be replicated properly.  (Bug #12870)

   * *Replication*: Replication of *Note `LOAD DATA INFILE': load-data.
     failed between systems using different path name syntax (such as
     delimiter characters).  (Bug #11815)

   * Local variables in stored routines were not always initialized
     correctly.  (Bug #13133)

   * The `FEDERATED' storage engine does not support *Note `ALTER
     TABLE': alter-table, but no appropriate error message was issued.
     (Bug #13108)

   * Columns named in the `USING()' clause of `JOIN ... USING()' were
     incorrectly resolved in case-sensitive fashion.  (Bug #13067)

   * For a server compiled with yaSSL, clients that used MySQL
     Connector/J were not able to establish SSH connections.  (Bug
     #13029)

   * When used in view definitions, `DAYNAME(EXPR)', `DAYOFWEEK(EXPR)',
     `WEEKDAY(EXPR)' were incorrectly treated as though the expression
     was `TO_DAYS(EXPR)' or `TO_DAYS(TO_DAYS(EXPR))'.  (Bug #13000)

   * Using `AS' to rename a column selected from a view in a subquery
     made it not possible to refer to that column in the outer query.
     (Bug #12993)

   * Using an `INOUT' parameter with a *Note `DECIMAL': numeric-types.
     data type in a stored procedure caused a server crash.  (Bug
     #12979)

   * `SELECT ... JOIN ... ON ... JOIN ... USING' caused a server crash.
     (Bug #12977)

   * A bug introduced in MySQL 5.0.12 caused *Note `SHOW TABLE STATUS':
     show-table-status. to display an `Auto_increment' value of 0 for
     `InnoDB' tables.  (Bug #12973)

   * On HP-UX 11.x (PA-RISC), the `-L' option caused *Note
     `mysqlimport': mysqlimport. to crash.  (Bug #12958)

   * `InnoDB': A consistent read could return inconsistent results due
     to a bug introduced in MySQL 5.0.5.  (Bug #12947)

   * Incorrect implicit nesting of joins caused the parser to fail on
     queries of the form `SELECT ... FROM t1 JOIN t2 JOIN t3 ON
     t1.t1col = t3.t3col' with an `Unknown column 't1.t1col' in 'on
     clause'' error.  (Bug #12943)

   * Incorrect results could be returned from a view processed using a
     temporary table.  (Bug #12941)

   * Multiplying a *Note `DECIMAL': numeric-types. value within a loop
     in a stored routine could incorrectly result in a value of `NULL'.
     (Bug #12938)

   * Using `GROUP BY' when selecting from a view in some cases could
     cause incorrect results to be returned.  (Bug #12922)

   * The counters for the `Key_read_requests', `Key_reads',
     `Key_write_requests', and `Key_writes' status variables were
     changed from `unsigned long' to `unsigned longlong' to accommodate
     larger values before the variables roll over and restart from 0.
     (Bug #12920)

   * *Note `mysql': mysql. and *Note `mysqldump': mysqldump. were
     ignoring the `--defaults-extra-file' option.  (Bug #12917)

   * `SHOW FIELDS FROM SCHEMANAME.VIEWNAME ' caused error 1046 when no
     default schema was set.  (Bug #12905)

   * `UNION [DISTINCT]' was not removing all duplicates for multi-byte
     character values.  (Bug #12891)

   * A column that can be `NULL' was not handled properly for `WITH
     ROLLUP' in a subquery or view.  (Bug #12885)

   * `GROUP_CONCAT()' ignored an empty string if it was the first value
     to occur in the result.  (Bug #12863)

   * If a client has opened an `InnoDB' table for which the `.ibd' file
     is missing, `InnoDB' would not honor a *Note `DROP TABLE':
     drop-table. statement for the table.  (Bug #12852)

   * Within a stored procedure, a server crash was caused by assigning
     to a `VARCHAR INOUT' parameter the value of an expression that
     included the variable itself. (For example, `SET c = c'.)  (Bug
     #12849)

   * The server crashed when one thread resized the query cache while
     another thread was using it.  (Bug #12848)

   * A concurrency problem for `CREATE ... SELECT' could cause a server
     crash.  (Bug #12845)

   * `DO IFNULL(NULL, NULL)' and `SELECT CAST(IFNULL(NULL, NULL) AS
     DECIMAL)' caused a server crash.  (Bug #12841)

   * After changing the character set with `SET CHARACTER SET', the
     result of the `GROUP_CONCAT()' function was not converted to the
     proper character set.  (Bug #12829)

   * The Windows installer made a change to one of the `mysql.proc'
     table files, causing stored routine functionality to be
     compromised. The Windows installer now never overwrites files in
     the MySQL data directory. During an upgrade from one version to
     another, a file in the data directory will not be overwritten even
     if it has not been modified since it was put there by an older
     installer.

     If you have already lost access to stored routines because of this
     problem, you can get them back using the following procedure:

        * Stop the server.

        * In the `mysql\data' directory under your MySQL installation
          directory, and replace the `proc.frm' file with corresponding
          file from the version of MySQL that you were using before you
          upgraded.

        * Start the server.

        * Start the *Note `mysql': mysql. command-line client (use the
          `root' account or another account that has full database
          privileges) and execute the `mysql_fix_privilege_tables.sql'
          script that upgrades the grant tables to the current
          structure.  Instructions for doing this are given in *Note
          mysql-fix-privilege-tables::.

     After this, all stored routine functionality should work.  (Bug
     #12820)

   * Queries with subqueries, where the inner subquery uses the `range'
     or `index_merge' access method, could return incorrect results.
     (Bug #12720)

   * The server failed to disallow *Note `SET autocommit': commit.  in
     stored functions and triggers. It is permitted to change the value
     of `autocommit' in stored procedures, but a runtime error might
     occur if the procedure is invoked from a stored function or
     trigger.  (Bug #12712)

   * Simultaneous execution of DML statements and *Note `CREATE
     TRIGGER': create-trigger. or *Note `DROP TRIGGER': drop-trigger.
     statements on the same table could cause server crashes or errors.
     (Bug #12704)

   * Performing an `IS NULL' check on the `MIN()' or `MAX()' of an
     indexed column in a complex query could produce incorrect results.
     (Bug #12695)

   * Use of *Note `PREPARE': prepare. and *Note `EXECUTE': execute.
     with a statement that selected from a view in a subquery could
     cause a server crash.  (Bug #12651)

   * If the binary log is enabled, execution of a stored procedure that
     modifies table data and uses user variables could cause a server
     crash or incorrect information to be written to the binary log.
     (Bug #12637)

   * The `LIKE ... ESCAPE' syntax produced invalid results when escape
     character was larger than one byte.  (Bug #12611)

   * *Note `mysqldump': mysqldump. did not dump triggers properly.
     (Bug #12597)

   * `InnoDB': Limit recursion depth to 200 in deadlock detection to
     avoid running out of stack space.  (Bug #12588)

   * The `mysql.server' script contained an incorrect path for the
     `libexec' directory.  (Bug #12550)

   * A *Note `UNION': union. of long `utf8' *Note `VARCHAR': char.
     columns was sometimes returned as a column with a *Note
     `LONGTEXT': blob. data type rather than *Note `VARCHAR': char. This
     could prevent such queries from working at all if selected into a
     `MEMORY' table because the `MEMORY' storage engine does not
     support the *Note `TEXT': blob. data types.  (Bug #12537)

   * A client connection thread cleanup problem caused the server to
     crash when closing the connection if the binary log was enabled.
     (Bug #12517)

   * Use of the *Note `mysql': mysql. client *Note `HELP': help.
     command from within a stored routine caused a `packets out of
     order' error and a lost connection. Now *Note `HELP': help. is
     detected and not permitted within stored routines.  (Bug #12490)

   * The `SYSDATE()' function now returns the time at which it was
     invoked. In particular, within a stored routine or trigger,
     `SYSDATE()' returns the time at which it executes, not the time at
     which the stored routine or triggering statement began to execute.
     (Bug #12480)

   * *Note `CREATE VIEW': create-view. inside a stored procedure caused
     a server crash if the table underlying the view had been deleted.
     (Bug #12468)

   * Deadlock occurred when several account management statements were
     run (particularly between *Note `FLUSH PRIVILEGES': flush./*Note
     `SET PASSWORD': set-password.  and *Note `GRANT': grant./*Note
     `REVOKE': revoke.  statements).  (Bug #12423)

   * `InnoDB' was too permissive with `LOCK TABLE ... READ LOCAL' and
     permitted new inserts into the table. Now `READ LOCAL' is
     equivalent to `READ' for `InnoDB'. This will cause slightly more
     locking in *Note `mysqldump': mysqldump, but makes `InnoDB' table
     dumps consistent with `MyISAM' table dumps.  (Bug #12410)

   * If a stored function invoked from a *Note `SELECT': select. failed
     with an error, it could cause the client connection to be dropped.
     Now such errors generate warnings instead so as not to interrupt
     the *Note `SELECT': select.  (Bug #12379)

   * The value of `character_set_results' could be set to `NULL', but
     returned the string `"NULL"' when retrieved.  (Bug #12363)

   * On Windows, the server was preventing tables from being created if
     the table name was a prefix of a forbidden name. For example,
     `nul' is a forbidden name because it is the same as a Windows
     device name, but a table with the name of `n' or `nu' was being
     forbidden as well.  (Bug #12325)

   * `ALTER TABLE ... DISCARD TABLESPACE' for non-`InnoDB' table caused
     the client to lose the connection. (The server was not returning
     the error properly.)  (Bug #12207)

   * Outer join elimination was erroneously applied for some queries
     that used a `NOT BETWEEN' condition, an `IN(VALUE_LIST)'
     condition, or an `IF()' condition.  (Bug #12102, Bug #12101)

   * Foreign keys were not properly enforced in `TEMPORARY' tables.
     Foreign keys are no longer permitted in `TEMPORARY' tables.  (Bug
     #12084)

   * When using a cursor, a *Note `SELECT': select.  statement that
     uses a `GROUP BY' clause could return incorrect results.  (Bug
     #11904)

   * The `character_set_system' system variable could not be selected
     with `SELECT @@character_set_system'.  (Bug #11775)

   * A memory leak resulting from repeated *Note `SELECT ... INTO':
     select. statements inside a stored procedure could cause the
     server to crash.  (Bug #11333)

   * Use of yaSSL for a secure client connection caused *Note `LOAD
     DATA LOCAL INFILE': load-data. to fail.  (Bug #11286)

   * *Note `mysqld_multi': mysqld-multi. now quotes arguments on command
     lines that it constructs to avoid problems with arguments that
     contain shell metacharacters.  (Bug #11280)

   * The server permitted privileges to be granted explicitly for the
     `INFORMATION_SCHEMA' database. Such privileges are always implicit
     and should not be grantable.  (Bug #10734)

   * *Note `SHOW CREATE PROCEDURE': show-create-procedure. and *Note
     `SHOW CREATE FUNCTION': show-create-function. no longer qualify
     the routine name with the database name, for consistency with the
     behavior of *Note `SHOW CREATE TABLE': show-create-table.  (Bug
     #10362)

   * The server incorrectly generated an `Unknown table' error message
     when for attempts to drop tables in the `INFORMATION_SCHEMA'
     database. Now it issues an `Access denied' message.  (Bug #9846)

   * Within a stored procedure, fetching a large number of rows in a
     loop using a cursor could result in a server crash or an out of
     memory error. Also, values inserted within a stored procedure
     using a cursor were interpreted as `latin1' even if character set
     variables had been set to a different character set.  (Bug #9819,
     Bug #6513)

   * The server permitted `TEMPORARY' tables and stored procedures to
     be created in the `INFORMATION_SCHEMA' database.  (Bug #9683, Bug
     #10708)

   * `SHOW FIELDS' truncated the `TYPE' column to 40 characters.  (Bug
     #7142) See also Bug #12817.

   * A view-creation statement of the form `CREATE VIEW NAME AS SELECT
     ... FROM TBL_NAME AS NAME' failed with a `Not unique table/alias:
     'NAME'' error.  (Bug #6808)

   * *Note `myisampack': myisampack. did not properly pack *Note
     `BLOB': blob. values larger than 2^24 bytes.  (Bug #4214)


File: manual.info,  Node: news-5-0-12,  Next: news-5-0-11,  Prev: news-5-0-13,  Up: news-5-0-x

D.1.85 Changes in MySQL 5.0.12 (02 September 2005)
--------------------------------------------------

*Functionality Added or Changed*

   * *Incompatible Change*: Beginning with MySQL 5.0.12, natural joins
     and joins with `USING', including outer join variants, are
     processed according to the SQL:2003 standard. The changes include
     elimination of redundant output columns for `NATURAL' joins and
     joins specified with a `USING' clause and proper ordering of output
     columns. The precedence of the comma operator also now is lower
     compared to `JOIN'.

     In addition, a `Duplicate column name error' no longer occurs when
     selecting from a view defined as `SELECT *' from a join that uses a
     `USING' clause on tables that have a common column name.

     These changes make MySQL more compliant with standard SQL.
     However, they can result in different output columns for some
     joins. Also, some queries that appeared to work correctly prior to
     5.0.12 must be rewritten to comply with the standard. For details
     about the scope of the changes and examples that show what query
     rewrites are necessary, see *Note join::.  (Bug #6495, Bug #6136,
     Bug #10972, Bug #9978, Bug #10428, Bug #10646, Bug #6276, Bug
     #6489, Bug #6558, Bug #9067, Bug #4789, Bug #12065, Bug #13551)

   * *MySQL Cluster*: The parsing of the `CLUSTERLOG' command by *Note
     `ndb_mgm': mysql-cluster-programs-ndb-mgm. was corrected to permit
     multiple items.  (Bug #12833)

   * *Replication*: Interleaved execution of stored procedures and
     functions could be written to the binary log incorrectly, causing
     replication slaves to get out of sync.  (Bug #12335)

   * *Replication*: Calls to stored procedures were written to the
     binary log even within transactions that were rolled back, causing
     them to be executed on replication slaves.  (Bug #12334)

   * A query of the form `SHOW TABLE STATUS FROM DB_NAME WHERE name IN
     (SELECT_QUERY)' would crash the server.  (Bug #12636)

   * Using *Note `DESCRIBE': describe. on a view after renaming a
     column in one of the view's base tables caused the server to crash.
     (Bug #12533)

   * If a thread (connection) has tables locked, the query cache is
     switched off for that thread. This prevents invalid results where
     the locking thread inserts values between a second thread
     connecting and selecting from the table.  (Bug #12385)

   * `SHOW TABLE STATUS FROM INFORMATION_SCHEMA' now sorts output by
     table name the same as it does for other databases.  (Bug #12315)

   * It is no longer possible to issue *Note `FLUSH': flush. statements
     from within stored functions or triggers. See *Note
     stored-program-restrictions::, for details.  (Bug #12280, Bug
     #12307)

   * *Note `SHOW OPEN TABLES': show-open-tables. now supports `FROM'
     and `LIKE' clauses.  (Bug #12183)

   * Recursive triggers are detected and not permitted. Also, within a
     stored function or trigger, it is not permissible to modify a
     table that is already being used (for reading or writing) by the
     statement that invoked the function or trigger.  (Bug #11896, Bug
     #12644)

   * `INFORMATION_SCHEMA' objects are now reported as a `SYSTEM VIEW'
     table type.  (Bug #11711)

   * The stability of cursors when used with `InnoDB' tables was
     greatly improved.  (Bug #11309, Bug #11832, Bug #12243)

   * Trying to drop the default keycache by setting
     `@@global.key_buffer_size' to zero now returns a warning that the
     default keycache cannot be dropped.  (Bug #10473)

   * *Note `SHOW ENGINE INNODB STATUS': show-engine. now can display
     longer query strings.  (Bug #7819)

   * Added the `SLEEP()' function, which pauses for the number of
     seconds given by its argument.  (Bug #6760)

   * *Note `SHOW TABLE STATUS': show-table-status. for a view now shows
     `VIEW' in uppercase, consistent with *Note `SHOW TABLES':
     show-tables. and `INFORMATION_SCHEMA'.  (Bug #5501)

*Bugs Fixed*

   * *MySQL Cluster*: When it could not copy a fragment, *Note `ndbd':
     mysql-cluster-programs-ndbd.  exited without printing a message
     about the condition to the error log. Now the message is written.
     (Bug #12900)

   * *MySQL Cluster*: When a `Disk is full' condition occurred, *Note
     `ndbd': mysql-cluster-programs-ndbd. exited without reporting this
     condition in the error log.  (Bug #12716)

   * *MySQL Cluster*: Cluster failed to take character set data into
     account when recomputing hashes (and thus could not locate records
     for updating or deletion) following a configuration change and node
     restart.  (Bug #12220)

   * *MySQL Cluster*: An *Note `ALTER TABLE': alter-table. statement
     caused loss of data stored prior to the issuing of the command.
     (Bug #12118)

   * *MySQL Cluster*: Invalid values in `config.ini' caused *Note
     `ndb_mgmd': mysql-cluster-programs-ndb-mgmd. to crash.  (Bug
     #12043)

   * *MySQL Cluster*: When a schema was detected to be corrupt, `ndb'
     neglected to close it, resulting in a `file already open' error if
     the schema was opened again later.  written.  (Bug #12027)

   * *MySQL Cluster*: Improved error messages related to file system
     issues.  (Bug #11218)

   * *MySQL Cluster*: The wrong error message was displayed when the
     cluster management server port was closed while a *Note `mysqld':
     mysqld. process was trying to connect.  (Bug #10950)

   * *Replication*: Some statements executed on a master server caused
     the SQL thread on a slave to run out of memory.  (Bug #12532)

   * *Replication*: Trigger and stored procedure execution could break
     replication.  (Bug #12482)

   * *Replication*: `NOW()', `CURRENT_TIME()' and values generated by
     timestamp columns are now constant for the duration of a stored
     function or trigger. This prevents the breaking of statement-based
     replication.  (Bug #12481)

   * *Replication*: Slave I/O threads were considered to be in the
     running state when launched (rather than after successfully
     connecting to the master server), resulting in incorrect *Note
     `SHOW SLAVE STATUS': show-slave-status. output.  (Bug #10780)

   * *Replication*: If a *Note `DROP DATABASE': drop-database. fails on
     a master server due to the presence of a nondatabase file in the
     database directory, the master have the database tables deleted,
     but not the slaves. To deal with failed database drops, we now
     write *Note `DROP TABLE': drop-table. statements to the binary log
     for the tables so that they are dropped on slaves.  (Bug #4680)

   * An optimizer estimate of zero rows for a nonempty `InnoDB' table
     used in a left or right join could cause incomplete rollback for
     the table.  (Bug #12779)

   * `mysql_fix_privilege_tables.sql' was missing a comma, causing a
     syntax error when executed.  (Bug #12705)

   * Invocations of the `SLEEP()' function incorrectly could be
     optimized away for statements in which it occurs. Statements
     containing `SLEEP()' incorrectly could be stored in the query
     cache.  (Bug #12689)

   * Improper use of loose index scan in `InnoDB' sometimes caused
     incorrect query results.  (Bug #12672)

   * A *Note `SELECT DISTINCT': select. query with a constant value for
     one of the columns would return only a single row.  (Bug #12625)

   * `SHOW TABLES FROM' returned the wrong error message if the schema
     specified did not exist.  (Bug #12591)

   * A server crash could result from an update of a view defined as a
     join, even though the update updated only a single table.  (Bug
     #12569)

   * *Note `DELETE': delete. or *Note `UPDATE': update. for an indexed
     `MyISAM' table could fail. This was due to a change in end-space
     comparison behavior from 4.0 to 4.1.  (Bug #12565)

   * The `COLUMN_DEFAULT' column of the *Note
     `INFORMATION_SCHEMA.COLUMNS': columns-table. table should be
     returned as `NULL' if a column has no default value. An empty
     string was being returned if the column was defined as `NOT NULL'.
     (Bug #12518)

   * The `ROW()' contructor returned an incorrect result when
     comparison involved `NULL' values.  (Bug #12509)

   * `STRCMP()' was not handled correctly in views.  (Bug #12489)

   * Selecting from a view defined as a join over many tables could
     result in a server crash due to miscalculation of the number of
     conditions in the `WHERE' clause.  (Bug #12470)

   * `MEMORY' tables using `B-Tree' index on 64-bit platforms could
     produce false table is full errors.  (Bug #12460)

   * The `CREATE_OPTIONS' column of *Note `INFORMATION_SCHEMA.TABLES':
     tables-table. showed incorrect options for tables in
     `INFORMATION_SCHEMA'.  (Bug #12397)

   * Mishandling of comparison for rows containing `NULL' values
     against rows produced by an `IN' subquery could cause a server
     crash.  (Bug #12392)

   * Selecting from a view after *Note `INSERT': insert. statements for
     the view's underlying table yielded different results than
     subsequent selects.  (Bug #12382)

   * Concatenating `USER()' or `DATABASE()' with a column produced
     invalid results.  (Bug #12351)

   * Comparison of `InnoDB' multi-part primary keys that include *Note
     `VARCHAR': char. columns can result in incorrect results.  (Bug
     #12340)

   * Renamed the `rest()' macro in `my_list.h' to `list_rest()' to
     avoid name clashes with user code.  (Bug #12327)

   * When restoring `INFORMATION_SCHEMA' as the default database after
     failing to execute a stored procedure in an inaccessible database,
     the server returned a spurious `ERROR 42000: Unknown database
     'information_schema'' message.  (Bug #12318)

   * Users created using an IP address or other alias rather than a
     host name listed in `/etc/hosts' could not set their own passwords.
     (Bug #12302)

   * The `NUMERIC_SCALE' column of the *Note
     `INFORMATION_SCHEMA.COLUMNS': columns-table. table should be
     returned as `0' for integer columns.  It was being returned as
     `NULL'.  (Bug #12301)

   * Creating a view that included the `TIMESTAMPDIFF()' function
     resulted in a invalid view.  (Bug #12298)

   * The *Note `CHECKSUM TABLE': checksum-table. statement returned
     incorrect results for tables with deleted rows. After upgrading,
     users who used stored checksum information to detect table changes
     should rebuild their checksum data.  (Bug #12296)

   * Inserting `NULL' into a `GEOMETRY' column for a table that has a
     trigger could result in a server crash if the table was
     subsequently dropped.  (Bug #12281)

   * *Note `myisampack': myisampack. failed to delete `.TMD' temporary
     files when run with the `-T' option.  (Bug #12235)

   * A race condition between server threads could cause a crash if one
     thread deleted a stored routine while another thread was executing
     a stored routine.  (Bug #12228)

   * Duplicate instructions in stored procedures resulted in incorrect
     execution when the optimizer optimized the duplicate code away.
     (Bug #12168)

   * `XA' permitted two active transactions to be started with the same
     XID.  (Bug #12162)

   * `NULL' column definitions were read incorrectly for inner tables
     of nested outer joins.  (Bug #12154)

   * `GROUP_CONCAT' ignored the `DISTINCT' modifier when used in a query
     joining multiple tables where one of the tables had a single row.
     (Bug #12095)

   * A failure to obtain a lock for a `LOCK IN SHARE MODE' query could
     result in a server crash.  (Bug #12082)

   * `SELECT ... INTO VAR_NAME ' within a trigger could cause a server
     crash.  (Bug #11973)

   * Using cursors and nested queries for the same table, corrupted
     results were returned for the outer query.  (Bug #11909)

   * A query using a `LEFT JOIN', an `IN' subquery on the outer table,
     and an `ORDER BY' clause, caused the server to crash when cursors
     were enabled.  (Bug #11901)

   * A *Note `UNION': union. query with `FULLTEXT' could cause server
     crash.  (Bug #11869)

   * Some subqueries of the form `SELECT ... WHERE ROW(...)  IN
     (SUBQUERY)' were being handled incorrectly.  (Bug #11867)

   * Column names in subqueries must be unique, but were not being
     checked for uniqueness.  (Bug #11864)

   * *Note `TRUNCATE TABLE': truncate-table. did not work with
     `TEMPORARY' `InnoDB' tables.  (Bug #11816)

   * The *Note `mysql_info()': mysql-info. C API function could return
     incorrect data when executed as part of a multi-statement that
     included a mix of statements that do and do not return information.
     (Bug #11688)

   * A trigger that included a *Note `SELECT': select.  statement could
     cause a server crash.  (Bug #11587)

   * Built-in commands for the *Note `mysql': mysql. client, such as
     `delimiter' and `\d', are now always parsed within files that are
     read using the `\.' and `source' commands.  (Bug #11523)

   * Added portability check for Intel compiler to address a problem
     compiling `InnoDB' code.  (Bug #11510)

   * `ALTER TABLE DB_NAME.T RENAME T' did not move the table to default
     database unless the new name was qualified with the database name.
     (Bug #11493)

   * Joins on *Note `VARCHAR': char. columns of different lengths could
     produce incorrect results.  (Bug #11398)

   * For PKG installs on Mac OS X, the preinstallation and
     postinstallation scripts were being run only for new installations
     and not for upgrade installations, resulting in an incomplete
     installation process.  (Bug #11380)

   * Prepared statement parameters could cause errors in the binary log
     if the character set was `cp932'.  (Bug #11338)

   * Columns defined as `TINYINT(1)' were redefined as `TINYINT(4)'
     when incorporated into a `VIEW'.  (Bug #11335)

   * Stored procedures with particularly long loops could crash the
     server due to a memory leak.  (Bug #11247, Bug #12297)

   * *Note `SET GLOBAL TRANSACTION ISOLATION LEVEL': set-transaction.
     was not working.  (Bug #11207)

   * It was permitted for a view to depend on a function that referred
     to a temporary table.  (Bug #10970)

   * Issuing `FLUSH INSTANCES' followed by `STOP INSTANCE' caused
     instance manager to crash.  (Bug #10957)

   * User variables were not automatically cast for comparisons,
     causing queries to fail if the column and connection character
     sets differed. Now when mixing strings with different character
     sets but the same coercibility, permit conversion if one character
     set is a superset of the other.  (Bug #10892)

   * An incorrect conversion from `double' to `ulonglong' caused
     indexes not to be used for `BDB' tables on HP-UX.  (Bug #10802)

   * `DATE_ADD()' and `DATE_SUB()' were converting invalid dates to
     `NULL' in `TRADITIONAL' SQL mode rather than rejecting them with
     an error.  (Bug #10627)

   * Views with multiple *Note `UNION': union. and *Note `UNION ALL':
     union.  produced incorrect results.  (Bug #10624)

   * It was not possible to create a stored function with a spatial
     return value data type.  (Bug #10499)

   * `INSERT ... SELECT ... ON DUPLICATE KEY UPDATE' could fail with an
     erroneous `Column 'COL_NAME' specified twice' error.  (Bug #10109)

   * The only valid values for the `PACK_KEYS' table option are 0 and
     1, but other values were being accepted.  (Bug #10056)

   * Using a stored procedure that referenced tables in the
     `INFORMATION_SCHEMA' database would return an empty result set.
     (Bug #10055, Bug #12278)

   * *Note `FLUSH TABLES WITH READ LOCK': flush. combined with `LOCK
     TABLE ..  WRITE' caused deadlock.  (Bug #9459)

   * A data type of `CHAR BINARY' was not recognized as valid for
     stored routine parameters.  (Bug #9048)

   * `ISO-8601' formatted dates were not being parsed correctly.  (Bug
     #7308)

   * On Windows when the `--innodb_buffer_pool_awe_mem_mb' option has
     been given, the server detects whether AWE support is available
     and has been compiled into the server, and displays an appropriate
     error message if not.  (Bug #6581)

   * Pathame values for options such as `--basedir' or `--datadir'
     didn't work on Japanese Windows machines for directory names
     containing multi-byte characters having a second byte of `0x5C'
     (``\'').  (Bug #5439)

   * *Note `SHOW TABLE STATUS': show-table-status. sometimes reported a
     `Row_format' value of `Dynamic' for `MEMORY' tables, though such
     tables always have a format of `Fixed'.  (Bug #3094)


File: manual.info,  Node: news-5-0-11,  Next: news-5-0-10,  Prev: news-5-0-12,  Up: news-5-0-x

D.1.86 Changes in MySQL 5.0.11 (06 August 2005)
-----------------------------------------------

*Functionality Added or Changed*

   * *MySQL Cluster*: Improved handling of the configuration variables
     `NoOfPagesToDiskDuringRestartACC',
     `NoOfPagesToDiskAfterRestartACC',
     `NoOfPagesToDiskDuringRestartTUP', and
     `NoOfPagesToDiskAfterRestartTUP' should result in noticeably
     faster startup times for MySQL Cluster.  (Bug #12149)

   * Added an optimization that avoids key access with `NULL' keys for
     the `ref' method when used in outer joins.  (Bug #12144)

   * Added support of where clause for queries with `FROM DUAL'.  (Bug
     #11745)

   * Maximum size of stored procedures increased from 64k to 4Gb.  (Bug
     #11602)

   * *Note `SHOW CHARACTER SET': show-character-set. and
     `INFORMATION_SCHEMA' now properly report the `Latin1' character
     set as `cp1252'.  (Bug #11216)

   * Added new `ER_STACK_OVERRUN_NEED_MORE' error message to indicate
     that, while the stack is not completely full, more stack space is
     required.  (Bug #11213)

   * *Note `mysqldump': mysqldump. now dumps triggers for each dumped
     table. This can be suppressed with the `--skip-triggers' option.
     (Bug #10431)

   * Added error message for users who attempt *Note `CREATE TABLE ...
     LIKE': create-table. and specify a nontable in the `LIKE' clause.
     (Bug #6859)

   * Security improvement: Applied a patch that addresses a potential
     `zlib' data vulnerability that could result in an application
     crash. This only affects the binaries for platforms that are
     linked statically against the bundled zlib (most notably Microsoft
     Windows and HP-UX).  (CVE-2005-1849)

*Bugs Fixed*

   * *MySQL Cluster*: The MySQL Cluster backup log was invalid where
     the number of Cluster nodes was not equal to a power of 2.  (Bug
     #11675)

   * Creation of the `mysql' group account failed during the RPM
     installation.  (Bug #12348)

   * Updated dependency list for RPM builds to include missing
     dependencies such as `useradd' and `groupadd'.  (Bug #12233)

   * A delayed insert that would duplicate an existing record crashed
     the server instead.  (Bug #12226)

   * When *Note `DROP DATABASE': drop-database. was called concurrently
     with a *Note `DROP TABLE': drop-table. of any table, the MySQL
     Server crashed.  (Bug #12212)

   * `InnoDB': True *Note `VARCHAR': char.: Return `NULL' columns in
     the format expected by MySQL.  (Bug #12186)

   * Information about a trigger was not displayed in the output of
     `SELECT ... FROM INFORMATION_SCHEMA.TRIGGERS' when the selected
     database was `INFORMATION_SCHEMA', prior to the trigger's first
     invocation.  (Bug #12127)

   * `InnoDB': Do not flush after each write, not even before setting
     up the doublewrite buffer. Flushing can be extremely slow on some
     systems.  (Bug #12125)

   * Two threads could potentially initialize different characters sets
     and overwrite each other.  (Bug #12109)

   * `big5' strings were not being stored in `FULLTEXT' index.  (Bug
     #12075)

   * Character data truncated when GBK characters `0xA3A0' and `0xA1'
     are present.  (Bug #11987)

   * *Note `ALTER TABLE': alter-table. when `sql_mode = 'TRADITIONAL''
     gave rise to an invalid error message.  (Bug #11964)

   * Issuing successive *Note `FLUSH TABLES WITH READ LOCK': flush.
     would cause the `mysql' client to hang.  (Bug #11934)

   * `mysql_install_db' used static `localhost' value in *Note `GRANT':
     grant. tables even when server host name is not `localhost', such
     as `localhost.localdomain'. This change is applied to version
     5.0.10b on Windows.  (Bug #11822)

   * Comparisons like `SELECT "A\\" LIKE "A\\";' fail when using `SET
     NAMES utf8;'.  (Bug #11754)

   * Attempting to repair a table having a full-text index on a column
     containing words whose length exceeded 21 characters and where
     `myisam_repair_threads' was greater than 1 would crash the server.
     (Bug #11684)

   * When used in a *Note `SELECT': select. query against a view, the
     `GROUP_CONCAT()' function returned only a single row.  (Bug #11412)

   * Multiplying `ABS()' output by a negative number would return
     incorrect results.  (Bug #11402)

   * The `LPAD()' and `RPAD()' functions returned the wrong length to
     *Note `mysql_fetch_fields()': mysql-fetch-fields.  (Bug #11311)

   * A `UNIQUE VARCHAR' column would be mis-identified as `MUL' in
     table descriptions.  (Bug #11227)

   * DDL statements are now permitted in stored procedures if the
     procedure is not invoked from a stored function or a trigger.
     This fix also resolves a problem where a `TEMPORARY' statement
     created by one stored routine was inaccessible to another routine
     invoked during the same connection.  (Bug #11126)

   * Calling the C API function *Note `mysql_stmt_fetch()':
     mysql-stmt-fetch. after all rows of a result set were exhausted
     would return an error instead of `MYSQL_NO_DATA'.  (Bug #11037)

   * `SELECT @@local...' returned `@@session...' in the column header.
     (Bug #10724)

   * Incorrect error message displayed if user attempted to create a
     table in a nonexisting database using `CREATE
     DATABASE_NAME.TABLE_NAME ' syntax.  (Bug #10407)

   * Unsigned `LONG' system variables may return incorrect value when
     retrieved with a *Note `SELECT': select. for certain values.  (Bug
     #10351)

   * `GROUP_CONCAT()' sometimes returned a result with a different
     collation from that of its arguments.  (Bug #10201)

   * Prepared statements were not being written to the Slow Query log.
     (Bug #9968)

   * The value of `max_connections_per_hour' was capped by the
     unrelated `max_user_connections' setting.  (Bug #9947)

   * In stored procedures, a cursor that fetched an empty string into a
     variable would set the variable to `NULL' instead.  (Bug #8692)

   * Added checks to prevent error when allocating memory when there
     was insufficient memory available.  (Bug #7003)

   * Multiple `SELECT SQL_CACHE' queries in a stored procedure causes
     error and client hang.  (Bug #6897)

   * A trigger dependent on a feature of one `sql_mode' setting would
     cause an error when invoked after the `sql_mode' was changed.
     (Bug #5891)


File: manual.info,  Node: news-5-0-10,  Next: news-5-0-9,  Prev: news-5-0-11,  Up: news-5-0-x

D.1.87 Changes in MySQL 5.0.10 (27 July 2005)
---------------------------------------------

*Functionality Added or Changed*

   * *Incompatible Change*: The namespace for triggers has changed.
     Previously, trigger names had to be unique per table. Now they
     must be unique within the schema (database). An implication of
     this change is that *Note `DROP TRIGGER': drop-trigger. syntax now
     uses a schema name instead of a table name (schema name is optional
     and, if omitted, the current schema will be used).

     *Note*:

     When upgrading from a version of MySQL 5 older than 5.0.10 to
     MySQL 5.0.10 or newer, you must drop all triggers and re-create
     them or *Note `DROP TRIGGER': drop-trigger.  will not work after
     the upgrade. A suggested procedure for doing this is given in
     *Note upgrading-from-previous-series::.

     (Bug #5892)

   * *MySQL Cluster*: A new `-P' option is available for use with the
     *Note `ndb_mgmd': mysql-cluster-programs-ndb-mgmd. client. When
     called with this option, *Note `ndb_mgmd':
     mysql-cluster-programs-ndb-mgmd. prints all configuration data to
     `stdout', then exits.

   * On Windows, the search path used by MySQL applications for
     `my.ini' now includes `..\my.ini' (that is, the application's
     parent directory, and hence, the installation directory).  (Bug
     #10419)

   * The viewing of triggers and trigger metadata has been enhanced as
     follows:

        * An extension to the *Note `SHOW': show.  command has been
          added: *Note `SHOW TRIGGERS': show-triggers. can be used to
          view a listing of triggers. See *Note show-triggers::, for
          details.

        * The `INFORMATION_SCHEMA' database now includes a *Note
          `TRIGGERS': triggers-table. table. See *Note
          triggers-table::, for details.

     (Bug #9586)

   * It is no longer necessary to issue an explicit *Note `LOCK
     TABLES': lock-tables. for any tables accessed by a trigger prior
     to executing any statements that might invoke the trigger.

     Previously, executing a statement that invoked a trigger would
     cause problems unless a *Note `LOCK TABLES': lock-tables. was
     first issued for any tables accessed by the trigger. The exact
     nature of the problem depended upon the MySQL 5.0 release being
     used: prior to 5.0.3, this resulted in a crash; from 5.0.3 to
     5.0.7, MySQL would issue a warning; in 5.0.9, the server would
     issue an error.

     The same issue caused *Note `LOCK TABLES': lock-tables.  to fail
     following *Note `UNLOCK TABLES': lock-tables. if triggers were
     involved.  (Bug #8406, Bug #9581)

   * The MySQL server now starts correctly with all combinations of
     `--basedir' and `--datadir', resolving an issue introduced by the
     original fix for this bug in MySQL 4.1.9.  (Bug #7249) See also
     Bug #7518.

   * Added *Note `mysql_get_character_set_info()':
     mysql-get-character-set-info. C API function for obtaining
     information about the default character set of the current
     connection.

   * An extension to the *Note `SHOW': show.  statement has been added:
     *Note `SHOW TRIGGERS': show-triggers. can be used to view a
     listing of triggers.  See *Note show-triggers::, for details.

   * Add the `--defaults-group-suffix' option. See *Note option-files::.

   * The bundled version of the `readline' library was upgraded to
     version 5.0.

   * Triggers can now reference tables by name. See *Note
     create-trigger::, for more information.

   * Add `table_lock_wait_timeout' global system variable.

*Bugs Fixed*

   * *Security Fix*: A vulnerability in `zlib' could result in a buffer
     overflow and arbitrary code execution.  (Bug #11844,
     CVE-2005-2096, CVE-2005-1849)

   * *MySQL Cluster*: The temporary tables created by an *Note `ALTER
     TABLE': alter-table. on an *Note `NDB': mysql-cluster. table were
     visible to all SQL nodes in the cluster.  (Bug #12055)

   * *MySQL Cluster*: *Note `NDB': mysql-cluster. ignored the
     `Hostname' option in the `[ndbd default]' section of the cluster
     configuration file.  (Bug #12028)

   * *MySQL Cluster*: The output of *Note `perror `--help'': perror.
     did not display any information about the `--ndb' option.  (Bug
     #11999)

   * *MySQL Cluster*: Attempting to create or drop tables during a
     backup would cause the cluster to shut down.  (Bug #11942)

   * *MySQL Cluster*: *Note `ndb_mgmd':
     mysql-cluster-programs-ndb-mgmd. leaked file descriptors.  (Bug
     #11898)

   * *MySQL Cluster*: The MySQL Server left core files following
     shutdown if data nodes had failed.  (Bug #11516)

   * *MySQL Cluster*: When attempting to drop a table with a broken
     unique index, *Note `NDB': mysql-cluster. failed to drop the table
     and erroneously report that the table was unknown.  (Bug #11355)

   * *MySQL Cluster*: Trying to use a greater number of tables than
     specified by the value of `MaxNoOfTables' caused table corruption
     such that data nodes could not be restarted.  (Bug #9994)

   * The server did not compile correctly when using `gcc4' on AMD64
     platforms.  (Bug #12040)

   * *Note `SHOW BINARY LOGS': show-binary-logs. displayed a file size
     of 0 for all log files but the current one if the files were not
     located in the data directory.  (Bug #12004)

   * Increased the version number of the `libmysqlclient' shared
     library from 14 to 15 because it is binary incompatible with the
     MySQL 4.1 client library.  (Bug #11893)

   * The server crashed when dropping a trigger that invoked a stored
     procedure, if the procedure was not yet in the connection-specific
     stored routine cache.  (Bug #11889)

   * `SELECT ... NOT IN()' gave unexpected results when only static
     value present between the `()'.  (Bug #11885)

   * A recent optimizer change caused `DELETE ... WHERE ...  NOT LIKE'
     and `DELETE ... WHERE ... NOT BETWEEN' to not properly identify
     the rows to be deleted.  (Bug #11853)

   * Execution of a prepared statement that invoked a nonexistent or
     dropped stored routine would crash the server.  (Bug #11834)

   * Selecting the result of an aggregate function for an *Note `ENUM':
     enum. or *Note `SET': set. column within a subquery could result
     in a server crash.  (Bug #11821)

   * Creating a table with a *Note `SET': set. or *Note `ENUM': enum.
     column with the `DEFAULT 0' clause caused a server crash if the
     table's character set was `utf8'.  (Bug #11819)

   * Incorrect column values could be retrieved from views defined
     using statements of the form `SELECT * FROM TBL_NAME'.  (Bug
     #11771)

   * When invoked within a view, `SUBTIME()' returned incorrect values.
     (Bug #11760)

   * For several character sets, MySQL incorrectly converted the
     character code for the division sign to the `eucjpms' character
     set.  (Bug #11717)

   * Performing an `ORDER BY' on a *Note `SELECT': select. from a
     `VIEW' produced unexpected results when `VIEW' and underlying
     table had the same column name on different columns.  (Bug #11709)

   * Execution of *Note `SHOW TABLES': show-tables. failed to increment
     the `Com_show_tables' status variable.  (Bug #11685)

   * LIKE pattern matching using prefix index didn't return correct
     result.  (Bug #11650)

   * Invoking the `DES_ENCRYPT()' function could cause a server crash
     if the server was started without the `--des-key-file' option.
     (Bug #11643)

   * IP addresses not shown in `ndb_mgm SHOW' command on second
     ndb_mgmd (or on ndb_mgmd restart).  (Bug #11596)

   * `SHOW PROCEDURE/FUNCTION STATUS' didn't work for users with
     limited access.  (Bug #11577)

   * `mysqlbinlog' was failing the test suite on Windows due to *Note
     `BOOL': numeric-types. being incorrectly cast to *Note `INT':
     numeric-types.  (Bug #11567)

   * The server crashed upon execution of a statement that used a
     stored function indirectly (via a view) if the function was not
     yet in the connection-specific stored routine cache and the
     statement would update a `Handler_XXX' status variable. This fix
     enables the use of stored routines under *Note `LOCK TABLES':
     lock-tables. without explicitly locking the `mysql.proc' table.
     However, you cannot use `mysql.proc' in statements that will
     combine locking of it with modifications for other tables.  (Bug
     #11554)

   * Aliasing the column names in a `VIEW' did not work when executing
     a *Note `SELECT': select.  query on the `VIEW'.  (Bug #11399)

   * The `mysql.proc' table was not being created properly with the
     proper `utf8' character set and collation, causing server crashes
     for stored procedure operations if the server was using a
     multi-byte character set.  To take advantage of the bug fix, *Note
     `mysql_fix_privilege_tables': mysql-fix-privilege-tables. should
     be run to correct the structure of the `mysql.proc' table.

     Note that it is _necessary_ to run `mysql_fix_privileges_tables'
     when upgrading from a previous installation that contains the
     `mysql.proc' table (that is, from a previous 5.0 installation).
     Otherwise, creating stored procedures might not work.  (Bug #11365)

   * For prepared statements, the SQL parser did not disallow ``?''
     parameter markers immediately adjacent to other tokens, which
     could result in malformed statements in the binary log. (For
     example, `SELECT * FROM t WHERE? = 1' could become `SELECT * FROM
     t WHERE0 = 1'.)  (Bug #11299)

   * The C API function *Note `mysql_stmt_reset()': mysql-stmt-reset.
     did not clear error information.  (Bug #11183)

   * *Note `INFORMATION_SCHEMA.COLUMNS': columns-table. had some
     inaccurate values for some data types.  (Bug #11057)

   * MySQL server would crash is a fetch was performed after a *Note
     `ROLLBACK': commit. when cursors were involved.  (Bug #10760)

   * When two threads competed for the same table, a deadlock could
     occur if one thread also had a lock on another table through *Note
     `LOCK TABLES': lock-tables. and the thread was attempting to
     remove the table in some manner while the other thread tried to
     place locks on both tables.  (Bug #10600)

   * When used within a subquery, `SUBSTRING()' returned an empty
     string.  (Bug #10269)

   * Multiple-table *Note `UPDATE': update. queries using
     `CONVERT_TZ()' would fail with an error.  (Bug #9979)

   * With strict SQL mode enabled, *Note `ALTER TABLE': alter-table.
     reported spurious `Invalid default value' messages for columns
     that had no `DEFAULT' clause.  (Bug #9881)

   * *Note `mysql_fetch_fields()': mysql-fetch-fields. returned
     incorrect length information for `MEDIUM' and `LONG' *Note `TEXT':
     blob. and *Note `BLOB': blob. columns.  (Bug #9735)

   * Within a stored procedure, selecting from a table through a view
     caused subsequent updates to the table to fail with a message that
     the table was read-locked.  (Bug #9597)

   * Within a stored procedure that selects from a table, invoking
     another procedure that requires a write lock for the table caused
     that procedure to fail with a message that the table was
     read-locked.  (Bug #9565)

   * Server-side prepared statements failed for columns with a
     character set of `ucs2'.  (Bug #9442)

   * In SQL prepared statements, comparisons could fail for values not
     equally space-padded. For example, `SELECT 'a' = 'a ';' returns 1,
     but `PREPARE s FROM 'SELECT ?=?'; SET @a = 'a', @b = 'a '; PREPARE
     s FROM 'SELECT ?=?'; EXECUTE s USING @a, @b;' incorrectly returned
     0.  (Bug #9379)

   * References to system variables in an SQL statement prepared with
     *Note `PREPARE': prepare. were evaluated during *Note `EXECUTE':
     execute. to their values at prepare time, not to their values at
     execution time.  (Bug #9359)

   * The server did not accept some fully-qualified trigger names.
     (Bug #8758)

   * Creating a trigger in one database that references a table in
     another database was being permitted without generating errors.
     (Bug #8751)

   * For a stored procedure defined with `SQL SECURITY DEFINER'
     characteristic, `CURRENT_USER()' incorrectly reported the use
     invoking the procedure, not the user who defined it.  (Bug #7291)

   * Labels in stored routines did not work if the character set was
     not `latin1'.  (Bug #7088)

   * Duplicate trigger names were permitted within a single schema.
     (Bug #6182)

   * For execution of a stored procedure that refers to a view, changes
     to the view definition were not seen. The procedure continued to
     see the old contents of the view.  (Bug #6120)

   * The `traditional' SQL mode accepted invalid dates if the date
     value provided was the result of an implicit type conversion.
     (Bug #5906)

   * In a shared Windows environment, MySQL could not find its
     configuration file unless the file was in the `C:\' directory.
     (Bug #5354)

   * Functions that evaluate to constants (such as `NOW()' and
     `CURRENT_USER()' were being evaluated in the definition of a
     `VIEW' rather than included verbatim.  (Bug #4663)


File: manual.info,  Node: news-5-0-9,  Next: news-5-0-8,  Prev: news-5-0-10,  Up: news-5-0-x

D.1.88 Changes in MySQL 5.0.9 (15 July 2005)
--------------------------------------------

*Functionality Added or Changed*

   * The handling of *Note `BIT': numeric-types. columns has been
     improved, and should now be much more reliable in a number of
     cases.  (Bug #11572, Bug #11091, Bug #10617)

   * Recursion in stored routines is now disabled because it was
     crashing the server.  (Bug #11394)

   * An attempt to create a *Note `TIMESTAMP': datetime.  column with a
     display width (for example, `TIMESTAMP(6)') now results in a
     warning.  Display widths have not been supported for *Note
     `TIMESTAMP': datetime. since MySQL 4.1.  (Bug #10466)

   * *Note `mysql_real_escape_string()': mysql-real-escape-string. API
     function now respects `NO_BACKSLASH_ESCAPES' SQL mode.  (Bug
     #10214)

   * `InnoDB': Made *Note `CHECK TABLE': check-table. killable.  (Bug
     #9730)

   * `InnoDB': Make `innodb_thread_concurrency = 20' by default.
     Bypass the concurrency checking if the setting is greater than or
     equal to 20.

   * `InnoDB': Various optimizations. Removed unreachable debug code
     from nondebug builds. Added hints for the branch predictor in
     `gcc'. Made assertions occupy less space.

   * `InnoDB': When creating or extending an `InnoDB' data file, at
     most one megabyte at a time is allocated for initializing the
     file. Previously, `InnoDB' allocated and initialized 1 or 8
     megabytes of memory, even if only a few 16-kilobyte pages were to
     be written. This improves the performance of *Note `CREATE TABLE':
     create-table. in `innodb_file_per_table' mode.

*Bugs Fixed*

   * *MySQL Cluster*: When trying to open a table that could not be
     discovered or unpacked, the cluster returned error codes which the
     MySQL server falsely interpreted as operating system errors.  (Bug
     #10365)

   * The `--master-data' option for *Note `mysqldump': mysqldump.
     resulted in no error if the binary log was not enabled. Now an
     error occurs unless the `--force' option is given.  (Bug #11678)

   * When a table had a primary key containing a *Note `BLOB': blob.
     column, creation of another index failed with the error `BLOB/TEXT
     column used in key specification without keylength', even when the
     new index did not contain a *Note `BLOB': blob.  column.  (Bug
     #11657)

   * Incorrect results when using `GROUP BY ... WITH ROLLUP' on a
     `VIEW'.  (Bug #11639)

   * MySQL would not compile correctly on QNX due to missing `rint()'
     function.  (Bug #11544)

   * A `SELECT DISTINCT COL_NAME ' would work correctly with a `MyISAM'
     table only when there was an index on COL_NAME.  (Bug #11484)

   * Using `CONCAT_WS()' on a column set `NOT NULL' caused incorrect
     results when used in a `LEFT JOIN'.  (Bug #11469)

   * Temporary tables were created in the data directory instead of
     `tmpdir'.  (Bug #11440)

   * Running a `CHECK TABLES' on multiple views crashed the server.
     (Bug #11337)

   * Manually inserting a row with `host=''' into `mysql.tables_priv'
     and performing a *Note `FLUSH PRIVILEGES': flush. would cause the
     server to crash.  (Bug #11330)

   * Wrong comparison method used in `VIEW' when relaxed date syntax
     used (for example, `2005.06.10').  (Bug #11325)

   * Signed *Note `BIGINT': numeric-types. would not accept
     `-9223372036854775808' as a `DEFAULT' value.  (Bug #11215)

   * Optimizer performed range check when comparing unsigned integers
     to negative constants, could cause errors.  (Bug #11185)

   * A cursor using a query with a filter on a *Note `DATE': datetime.
     or *Note `DATETIME': datetime. column would cause the server to
     crash server after the data was fetched.  (Bug #11172)

   * The `mysql_config' script did not handle symbolic linking properly.
     (Bug #10986)

   * *Note `mysqldump': mysqldump. failed when reloading a view if the
     view was defined in terms of a different view that had not yet
     been reloaded. *Note `mysqldump': mysqldump. now creates a dummy
     table to handle this case.  (Bug #10927)

   * If a prepared statement cursor is opened but not completely
     fetched, attempting to open a cursor for a second prepared
     statement will fail.  (Bug #10794)

   * Combining cursors and subqueries could cause server crash or
     memory leaks.  (Bug #10736)

   * Instances of the `VAR_SAMP()' function in view definitions were
     converted to `VARIANCE()'. This is incorrect because `VARIANCE()'
     is the same as `VAR_POP()', not `VAR_SAMP()'.  (Bug #10651)

   * `DES_ENCRYPT()' and `DES_DECRYPT()' require SSL support to be
     enabled, but were not checking for it. Checking for incorrect
     arguments or resource exhaustion was also improved for these
     functions.  (Bug #10589)

   * For `MEMORY' tables, it was possible for updates to be performed
     using outdated key statistics when the updates involved only very
     small changes in a very few rows.  This resulted in the random
     failures of queries such as `UPDATE t SET col = col + 1 WHERE
     col_key = 2;' where the same query with no `WHERE' clause would
     succeed.  (Bug #10178)

   * When used in joins, `SUBSTRING()' failed to truncate to zero those
     string values that could not be converted to numbers.  (Bug #10124)

   * Views did not use indexes on all appropriate queries.  (Bug #10031)

   * Closing a cursor that was already closed would cause MySQL to hang.
     (Bug #9814)

   * The server would lose table-level *Note `CREATE VIEW':
     create-view. and `SHOW VIEW' privileges following a *Note `FLUSH
     PRIVILEGES': flush. or server restart.  (Bug #9795)

   * `mysqldump --xml' did not format `NULL' column values correctly.
     (Bug #9657)

   * The `--no-data' option for *Note `mysqldump': mysqldump. was being
     ignored if table names were given after the database name.  (Bug
     #9558)

   * Clients would hang following some errors with stored procedures.
     (Bug #9503)

   * *Note `mysqldump': mysqldump. could crash for illegal or
     nonexistent table names.  (Bug #9358)

   * A compression algorithm issue caused `myisampack'to fail for very
     large data sets (where the total size of all records in a single
     column was on the order of 3 GB or more) on 64-bit platforms. (A
     fix for other platforms was made in MySQL 5.0.6.)  (Bug #8321)

   * The `ENCRYPT()' and `SUBSTRING_INDEX()' functions would cause
     errors when used with a `VIEW'.  (Bug #7024)

   * *Note `SHOW CREATE VIEW': show-create-view. did not take the
     `ANSI' SQL mode into account when quoting identifiers.  (Bug #6903)

   * In strict mode, an *Note `INSERT': insert. into a view that did
     not include a value for a `NOT NULL' column but that did include a
     `WHERE' test on the same column would succeed, This happened even
     though the *Note `INSERT': insert. should have been prevented due
     to the failure to supply a value for the `NOT NULL' column.  (Bug
     #6443)


File: manual.info,  Node: news-5-0-8,  Next: news-5-0-7,  Prev: news-5-0-9,  Up: news-5-0-x

D.1.89 Changes in MySQL 5.0.8 (Not released)
--------------------------------------------

*Note*:

Starting with version 5.0.8, changes for MySQL Cluster can be found in
the combined Change History.

*Functionality Added or Changed*

   * *Incompatible Change*: Previously, conversion of *Note `DATETIME':
     datetime. values to numeric form by adding zero produced a result
     in `YYYYMMDDHHMMSS' format. The result of `DATETIME+0' is now in
     `YYYYMMDDHHMMSS.000000' format.  (Bug #12268)

   * *Replication*: Some data definition statements (*Note `CREATE
     TABLE': create-table. where the table was not a temporary table,
     *Note `TRUNCATE TABLE': truncate-table, *Note `DROP DATABASE':
     drop-database, and *Note `CREATE DATABASE': create-database.) were
     not being written to the binary log after a *Note `ROLLBACK':
     commit. This also caused problems with replication.

     *Important*:

     As a result of this fix, the following statements now cause an
     implicit commit:

        * *Note `CREATE TABLE': create-table.

        * *Note `TRUNCATE TABLE': truncate-table.

        * *Note `DROP DATABASE': drop-database.

        * *Note `CREATE DATABASE': create-database.

     (Bug #6883)

   * Where a `GROUP BY' query uses a grouping column from the query's
     *Note `SELECT': select. clause, MySQL now issues a warning. This
     is done because the SQL standard states that any grouping column
     must unambiguously reference a column of the table resulting from
     the query's `FROM' clause, and permitting columns from the *Note
     `SELECT': select. clause to be used as grouping columns is a MySQL
     extension to the standard.

     By way of example, consider the following table:

          CREATE TABLE users (
            userid INT NOT NULL PRIMARY KEY,
            username VARCHAR(25),
            usergroupid INT NOT NULL
          );

     MySQL enables you to use the alias in this query:

          SELECT usergroupid AS id, COUNT(userid) AS number_of_users
          FROM users
          GROUP BY id;

     However, the SQL standard requires that the column name be used,
     as shown here:

          SELECT usergroupid AS id, COUNT(userid) AS number_of_users
          FROM users
          GROUP BY usergroupid;

     Queries such as the first of the two shown above will continue to
     be supported in MySQL; however, beginning with MySQL 5.0.8, using
     a column alias in this fashion will generate a warning.  Note that
     in the event of a collision between column names or aliases used
     in joins, MySQL attempts to resolve the conflict by giving
     preference to columns arising from tables named in the query's
     `FROM' clause.  (Bug #11211)

   * Using prepared statements within a stored routine (*Note
     `PREPARE': prepare, *Note `EXECUTE': execute, *Note `DEALLOCATE
     PREPARE': deallocate-prepare.) could cause the client connection
     to be dropped after the routine returned.  In addition, executing
     a statement which called a function deallocating the same
     statement caused the server to crash. This is prevented by
     disabling dynamic SQL within stored routines.

     *Note*:

     This restriction was lifted in 5.0.13 for stored procedures, but
     not stored functions or triggers.

     (Bug #10975, Bug #10605) See also Bug #7115.

   * Added support for `B'10'' syntax for bit literal.  (Bug #10650)

   * `MEMORY' tables now support indexes of up to 500 bytes. See *Note
     memory-storage-engine::.  (Bug #10566)

   * Expanded on information provided in general log and slow query log
     for prepared statements.  (Bug #8367, Bug #9334)

   * New `sql_mode' mode `NO_ENGINE_SUBSTITUTION' prevents automatic
     substitution of storage engine when the requested storage engine
     is disabled or not compiled in.  (Bug #6877)

*Bugs Fixed*

   * *Security Fix*: On Windows systems, a user with any of the
     following privileges on `*.*' could crash *Note `mysqld': mysqld.
     by issuing a `USE LPT1;' or `USE PRN;' command:

        * `REFERENCES'

        * `CREATE TEMPORARY TABLES'

        * `GRANT OPTION'

        * `CREATE'

        * *Note `SELECT': select.

     In addition, any of the commands `USE NUL;', `USE CON;', `USE
     COM1;', or `USE AUX;' would report success even though the
     database was not in fact changed.

     *Note*:

     Although this bug was thought to be fixed previously, it was later
     discovered to be present in the MySQL 5.0.7-beta release for
     Windows.

     (Bug #9148)

   * *MySQL Cluster*: Setting `TransactionInactiveTimeout = 0' did not
     result in an infinite timeout.  (Bug #11290)

   * *MySQL Cluster*: *Note `mysqld': mysqld. processes did not
     reconnect to the cluster following a restart of *Note `ndb_mgmd':
     mysql-cluster-programs-ndb-mgmd.  (Bug #11221)

   * *MySQL Cluster*: Insert records were incorrectly applied by *Note
     `ndb_restore': mysql-cluster-programs-ndb-restore, thus making
     restoring from backup inconsistent if the binary log contained
     inserts.  (Bug #11166)

   * *MySQL Cluster*: A *Note `DELETE': delete. performed as part of a
     transaction caused an erroneous result.  (Bug #11133)

   * *MySQL Cluster*: Connections between data nodes and management
     nodes were not closed following shutdown of *Note `ndb_mgmd':
     mysql-cluster-programs-ndb-mgmd.  (Bug #11132)

   * *MySQL Cluster*: The *Note `ndb_mgm':
     mysql-cluster-programs-ndb-mgm. client's *Note `SHOW': show.
     command displayed incorrect output after master data node failure.
     (Bug #11050)

   * *MySQL Cluster*: When using dynamically allocated ports on Linux,
     the cluster would hang on initial startup.  (Bug #10893)

   * *MySQL Cluster*: Not permitting sufficient parallelism in the
     cluster's configuration (for example, by setting
     `NoOfTransactions' too small) caused *Note `ndb_restore':
     mysql-cluster-programs-ndb-restore. to fail without providing any
     error messages.  (Bug #10294)

   * *MySQL Cluster*: Running *Note `ndb_select_count':
     mysql-cluster-programs-ndb-select-count. crashed the cluster when
     running on Red Hat Enterprise 4/64-bit/Opteron.  (Bug #10058)

   * *MySQL Cluster*: Data nodes failed to restart on 64-bit Solaris.
     (Bug #9025)

   * *MySQL Cluster*: On 64-bit Solaris 9, the cluster timed out and
     crashed after the first query was made.  (Bug #8918)

   * *Replication*: An invalid comparison caused warnings for packet
     length in replication on 64-bit compilers.  (Bug #11064)

   * Multiple range accesses in a subquery cause server crash.  (Bug
     #11487)

   * A `CAST()' value could not be included in a `VIEW'.  (Bug #11387)

   * Server crashed when using `GROUP BY' on the result of a `DIV'
     operation on a *Note `DATETIME': datetime. value.  (Bug #11385)

   * `INSERT INTO SELECT FROM VIEW ' produced incorrect result when
     using `ORDER BY'.  (Bug #11298)

   * Possible `NULL' values in *Note `BLOB': blob. columns could crash
     the server when a *Note `BLOB': blob. was used in a `GROUP BY'
     query.  (Bug #11295)

   * An outer join with an `ON' condition that evaluated to false could
     return an incorrect result.  (Bug #11285)

   * An outer join with an empty derived table (a result from a
     subquery) returned no result.  (Bug #11284)

   * `CAST( ... AS DECIMAL)' didn't work for strings.  (Bug #11283)

   * Corrected a problem with `IFNULL()' returning an incorrect result
     on 64-bit systems.  (Bug #11235)

   * The `SHOW INSTANCE OPTIONS' command in MySQL Instance Manager
     displayed option values incorrectly for options for which no value
     had been given.  (Bug #11200)

   * The default host name for MySQL server was always `mysql'.  (Bug
     #11174)

   * Some internal functions did not take into account that, for
     multi-byte character sets, *Note `CHAR': char.  columns could
     exceed 255 bytes and *Note `VARCHAR': char. columns could exceed
     65,535 bytes, which could cause the server to crash.  (Bug #11167)

   * There were locking problems with multiple-statement *Note
     `DELETE': delete. statements performed within a stored routine,
     such as incorrectly locking the table to be read with a read lock
     rather than a write lock.  (Bug #11158)

   * Testing for `crypt()' support caused compilation problems when
     using OpenSSL/yaSSL on HP-UX and Mac OS X.  (Bug #11150, Bug
     #10675)

   * The `NULLIF()' function could produce incorrect results if the
     first argument was `NULL'.  (Bug #11142)

   * `mysqld_safe' would sometimes fail to remove the pid file for the
     old `mysql' process after a crash. As a result, the server would
     fail to start due to a false `A mysqld process already exists...'
     error.  (Bug #11122)

   * Calling a stored procedure that made use of an `INSERT ... SELECT
     ... UNION SELECT ...' query caused a server crash.  (Bug #11060)

   * `sql_data_access' column of `routines' table of
     `INFORMATION_SCHEMA' was empty.  (Bug #11055)

   * *Note `SELECT DISTINCT': select. queries or `GROUP BY' queries
     without `MIN()' or `MAX()' could return inconsistent results for
     indexed columns.  (Bug #11044)

   * A *Note `CREATE TABLE DB_NAME.TBL_NAME LIKE ...': create-table.
     statement would crash the server when no database was selected.
     (Bug #11028)

   * On Windows, `mysqlshow' did not interpret wildcard characters
     properly if they were given in the table name argument.  (Bug
     #10947)

   * The host name cache was not working.  (Bug #10931)

   * A three byte buffer overflow in the client functions caused
     improper exiting of the client when reading a command from the
     user.  (Bug #10841)

   * The *Note `mysql': mysql. client would output a prompt twice
     following input of very long strings, because it incorrectly
     assumed that a call to the `_cgets()' function would clear the
     input buffer.  (Bug #10840)

   * Setting `@@sql_mode = NULL' caused an erroneous error message.
     (Bug #10732)

   * When using a cursor with a prepared statement, the first execution
     returned the correct result but was not cleaned up properly,
     causing subsequent executions to return incorrect results.  (Bug
     #10729)

   * Converting a *Note `VARCHAR': char. column having an index to a
     different type (such as *Note `TINYTEXT': blob.) gave rise to an
     incorrect error message.

     Note that this bug fix induces a slight change in the behavior of
     indexes: If an index is defined to be the same length as a field
     (or is left to default to that field's length), and the length of
     the field is later changed, then the index will adopt the new
     length of the field. Previously, the size of the index did not
     change for some field types (such as *Note `VARCHAR': char.) when
     the field type was changed.  (Bug #10543)

   * `InnoDB': Pad UTF-8 *Note `VARCHAR': char. columns with `0x20'.
     Pad UCS2 *Note `CHAR': char. columns with `0x0020'.  (Bug #10511)

   * `InnoDB': Enforce maximum `CHAR_LENGTH()' of UTF-8 data in `ON
     UPDATE CASCADE'.  (Bug #10409)

   * `SELECT * FROM TABLE ' returned incorrect results when called from
     a stored procedure, where TABLE had a primary key.  (Bug #10136)

   * The granting and revocation of privileges on a stored routine was
     performed when running the server with `--skip-grant-tables' even
     after the statement `SET @@GLOBAL.automatic_sp_privileges = 1;'
     was executed.  (Bug #9993)

   * A stored procedure run while the query cache was enabled could
     cause the server to crash.  (Bug #9715)

   * Table names were not handled correctly when
     `lower_case_table_names = 2' if the table name lettercase differed
     in the `FROM' and `WHERE' clauses.  (Bug #9500)

   * `SHOW CREATE DATABASE INFORMATION_SCHEMA' returned an `unknown
     database' error.  (Bug #9434)

   * `SELECT DISTINCT ... GROUP BY CONSTANT' returned multiple rows (it
     should return a single row).  (Bug #8614)

   * An issue with index merging could cause suboptimal index merge
     plans to be chosen when searching by indexes created on *Note
     `DATE': datetime. columns. The same issue caused the `InnoDB'
     storage engine to issue the warning `using a partial-field key
     prefix in search'.  (Bug #8441)

   * The `mysqlhotcopy' script was not parsing the output of *Note
     `SHOW SLAVE STATUS': show-slave-status.  correctly when called
     with the `--record_log_pos' option.  (Bug #7967)

   * A Boolean full-text search where a query contained more query
     terms than one-third of the query length caused the server to hang
     or crash.  (Bug #7858)

   * When used in defining a view, the `TIME_FORMAT()' function failed
     with calculated values, for example, when passed the value
     returned by `SEC_TO_TIME()'.  (Bug #7521)

   * Views could be created with duplicate column names.  (Bug #7448)

   * An `ORDER BY' clause sometimes had no effect on the ordering of a
     result when selecting specific columns (as opposed to using
     `SELECT *') from a view.  (Bug #7422)

   * Using *Note `PREPARE': prepare. to prepare a statement that
     invoked a stored routine that executed the prepared statement
     caused a `Packets out of order error' the second time the routine
     was invoked. This is prevented by disabling dynamic SQL within
     stored routines.

     *Note*:

     This restriction was lifted in 5.0.13 for stored procedures, but
     not for stored functions or triggers.

     (Bug #7115) See also Bug #10975, Bug #10605.

   * Selecting from a view defined using `SELECT SUM(DISTINCT ...)'
     caused an error; attempting to execute a `SELECT * FROM
     INFORMATION_SCHEMA.TABLES' query after defining such a view
     crashed the server.  (Bug #7015)


File: manual.info,  Node: news-5-0-7,  Next: news-5-0-6,  Prev: news-5-0-8,  Up: news-5-0-x

D.1.90 Changes in MySQL 5.0.7 (10 June 2005)
--------------------------------------------

*Functionality Added or Changed*

   * *Security Fix*: A UDF library-loading vulnerability could result
     in a buffer overflow and code execution.  (CVE-2005-2558)

   * Improved the optimizer to be able to use indexes for expressions
     of the form `INDEXED_COL NOT IN (VAL1, VAL2, ...)' and `
     INDEXED_COL NOT BETWEEN VAL1 AND VAL2'.  (Bug #10561)

   * The `table', `type', and `rows' columns of *Note `EXPLAIN':
     explain. output can now be `NULL'. This is required for using
     *Note `EXPLAIN': explain. on *Note `SELECT': select. queries that
     use no tables, such as `EXPLAIN SELECT 1').  (Bug #9899)

   * All characters occurring on the same line following the
     `DELIMITER' keyword will be set as delimiter.  For example,
     `DELIMITER :;' will set `:;' as the delimiter. This behavior is now
     consistent between MySQL 5.1 and MySQL 5.0.  (Bug #9879)

   * Added *Note `mysql_set_character_set()': mysql-set-character-set.
     C API function for setting the default character set of the
     current connection. This enables clients to affect the character
     set used by *Note `mysql_real_escape_string()':
     mysql-real-escape-string.  (Bug #8317)

   * The `--delayed-insert' option for *Note `mysqldump': mysqldump.
     was disabled to avoid causing problems with storage engines that
     do not support *Note `INSERT DELAYED': insert-delayed.  (Bug #7815)

   * Placeholders now can be used for `LIMIT' in prepared statements.
     (Bug #7306)

   * `InnoDB': In stored procedures and functions, `InnoDB' no longer
     takes full explicit table locks for every involved table. Only
     `intention' locks are taken, similar to those in the execution of
     an ordinary SQL statement. This greatly reduces the number of
     deadlocks.

   * *Note `SHOW BINARY LOGS': show-binary-logs. now displays a
     `File_size' column that indicates the size of each file.

   * Removed `WinMySQLAdmin' from the source distribution and from the
     `No Installer' Windows distribution (it had already been removed
     from the `With Installer' distribution before).

   * The behavior of the `Last_query_cost' system variable has been
     changed. The default value is now 0 (rather than -1) and it now
     has session-level scope (rather than being global). See *Note
     server-status-variables::, for additional information.

   * Removed `mysqlshutdown.exe' and `mysqlwatch.exe' from the Windows
     `No Installer' distribution (they had already been removed from
     the `With Installer' distribution before).  Removed those programs
     from the source distribution.

*Bugs Fixed*

   * MySQL would pass an incorrect key length to storage engines for
     `MIN()'. This could cause spurious warnings such as `InnoDB:
     Warning: using a partial-field key prefix in search' to appear in
     the `.err' log.  (Bug #13218, Bug #11039)

   * Build failures occurred when compiling the server on Windows using
     Visual Studio 6.  (Bug #11153)

   * Corrected a problem where an incorrect data type was returned in
     the result set metadata when using a prepared *Note `SELECT
     DISTINCT': select. statement to select from a view.  (Bug #11111)

   * The server could crash due to an attempt to allocate too much
     memory when `GROUP BY BLOB_COL' and `COUNT(DISTINCT)' were used.
     (Bug #11088)

   * Multiple-row *Note `REPLACE': replace. could fail on a
     duplicate-key error when having one `AUTO_INCREMENT' key and one
     unique key.  (Bug #11080)

   * `InnoDB': A duplicate key error occurred with *Note `REPLACE':
     replace. in a table having an `AUTO_INCREMENT' column.  (Bug
     #11005)

   * `WITH ROLLUP' did not sum values properly.  (Bug #10982)

   * *Security update*: A user with limited privileges could obtain
     information about the privileges of other users by querying
     objects in the `INFORMATION_SCHEMA' database for which that user
     did not have the requisite privileges.  (Bug #10964)

   * The value returned by the `FIELD()' function was incorrect when
     its parameter list contained one or more instances of `NULL'.
     (Bug #10944)

   * Failure of a `BEFORE' trigger did not prevent the triggering
     statement from performing its operation on the row for which the
     trigger error occurred. Now the triggering statement fails as
     described in *Note triggers::.  (Bug #10902)

   * The `FEDERATED' storage engine properly handled outer joins, but
     not inner joins.  (Bug #10848)

   * Executing *Note `LOAD INDEX INTO CACHE': load-index. for a table
     while other threads where selecting from the table caused a
     deadlock.  (Bug #10602)

   * The `TIME_FORMAT()' function returned incorrect results with some
     format specifiers. See *Note date-and-time-functions::.  (Bug
     #10590)

   * The `LAST_DAY()' failed to return `NULL' when supplied with an
     invalid argument.  See *Note date-and-time-functions::.  (Bug
     #10568)

   * A problem with the `my_global.h' file caused compilation of MySQL
     to fail on single-processor Linux systems running 2.6 kernels.
     (Bug #10364)

   * Corrected inappropriate error messages that were displayed when
     attempting to set the read-only `warning_count' and `error_count'
     system variables.  (Bug #10339)

   * The MySQL Instance manager caused the version to be displayed as
     `unknown' by `SHOW INSTANCE STATUS'.  (Bug #10229)

   * A simultaneous *Note `CREATE TABLE ... SELECT FROM TABLE':
     create-table-select.  and `ALTER TABLE TABLE' on the same table
     caused the server to crash.  (Bug #10224)

   * Under certain rare circumstances, inserting into the `mysql.host'
     table could cause the server to crash.  (Bug #10181)

   * Consistently report `INFORMATION_SCHEMA' table names in uppercase
     in *Note `SHOW TABLE STATUS': show-table-status. output.  (Bug
     #10059)

   * Accessing `InnoDB' tables within stored functions caused the MySQL
     server to crash. Now, statements that perform an implicit or
     explicit commit or rollback are prohibited within stored functions
     or triggers.  (Bug #10015)

   * Issuing a write lock for a table from one client prevented other
     clients from accessing the table's metadata. For example, if one
     client issued a `LOCK TABLES MYDB.MYTABLE WRITE', then a second
     client attempting to execute a `USE MYDB;' would hang.  (Bug #9998)

   * Dropping stored routines when the MySQL server had been started
     with `--skip-grant-tables' generated extraneous warnings.  (Bug
     #9993)

   * The *Note `mysql_next_result()': mysql-next-result. function could
     hang if you were executing many statements in a *Note
     `mysql_real_query()': mysql-real-query. call and one of those
     statements raised an error.  (Bug #9992)

   * The functions `COALESCE()', `IF()', and `IFNULL()' performed
     incorrect conversions of their arguments.  (Bug #9939)

   * An incorrect result was returned from a view that selected a
     `COALESCE()' expression from the result of an outer join.  (Bug
     #9938)

   * `InnoDB': Do very fast shutdown only if `innodb_fast_shutdown =
     2', but wait for threads to exit and release allocated memory if
     `innodb_fast_shutdown = 1'. Starting with MySQL/InnoDB 5.0.5,
     `InnoDB' would do brutal shutdown also when `innodb_fast_shutdown
     = 1'.  (Bug #9673)

   * Using `ORDER BY' to sort the results of an `IF()' that contained a
     `FROM_UNIXTIME()' expression returned incorrect results due to
     integer overflow.  (Bug #9669)

   * On Windows, with `lower_case_table_names' set to 2, using *Note
     `ALTER TABLE': alter-table. to alter a `MEMORY' or `InnoDB' table
     that had a mixed-case name also improperly changed the name to
     lowercase.  (Bug #9660)

   * The combination of `COUNT()', `DISTINCT', and `CONCAT()' sometimes
     triggered a memory deallocation bug on Windows resulting in a
     server crash.  (Bug #9593)

   * `INSERT BEFORE' triggers were not being activated for implicit
     inserts (*Note `LOAD DATA': load-data.).  (Bug #8755)

   * The ucs2_turkish_ci collation failed with upper('i').  UPPER/LOWER
     now can return a string with different length.  (Bug #8610)

   * The server timed out SSL connections too quickly on Windows.  (Bug
     #8572)

   * If a stored function contained a *Note `FLUSH': flush. statement,
     the function crashed when invoked. *Note `FLUSH': flush. is no
     longer permitted within stored functions.  (Bug #8409)

   * `OPTIMIZE' run on an `InnoDB' table did not return a `Table is
     full' error if there was insufficient room in the tablespace.
     (Bug #8135)

   * An incorrect result was obtained for columns that included an
     aggregate function as part of an expression, and when `WITH
     ROLLUP' was used with `GROUP BY'.  (Bug #7914)

   * Queries with `ROLLUP' returned wrong results for expressions
     containing`GROUP BY' columns.  (Bug #7894)

   * The second invocation of a stored procedure that selected from a
     view defined as a join using `ON' in the join condition could
     cause the server to crash.  (Bug #6866)

   * `INSERT BEFORE' triggers were not being activated for *Note
     `INSERT ... SELECT': insert-select. statements.  (Bug #6812)

   * *Note `INSERT': insert. or *Note `UPDATE': update. when the
     `WHERE' clause contained a correlated subquery that referred to a
     column of the table being modified caused the server to crash.
     (Bug #6384)

   * MySQL was adding a `DEFAULT' clause to *Note `ENUM': enum. columns
     that included no explicit `DEFAULT' and were defined as `NOT
     NULL'. (This is supposed to happen only for columns that are
     `NULL'.)  (Bug #6267)

   * Using *Note `ALTER TABLE': alter-table. for a table that had a
     trigger caused a crash when executing a statement that activated
     the trigger, and also a crash later with `USE DB_NAME' for the
     database containing the table.  (Bug #5894)

   * Triggers with dropped functions caused crashes.  (Bug #5893)

   * Triggers were not being activated for multiple-table *Note
     `UPDATE': update. or *Note `DELETE': delete. statements.  (Bug
     #5860)

   * The incorrect sequence of statements `HANDLER TBL_NAME READ
     INDEX_NAME NEXT' without a preceding `HANDLER TBL_NAME READ
     INDEX_NAME = (VALUE_LIST)' for an `InnoDB' table resulted in a
     server crash rather than an error.  (Bug #5373)

   * Multiple-table *Note `DELETE': delete. always deleted on the fly
     from the first table that was to be deleted from. In some cases,
     when using many tables and when necessary to access the same row
     twice in the first table, some rows to be deleted from other
     tables could be missed.


File: manual.info,  Node: news-5-0-6,  Next: news-5-0-5,  Prev: news-5-0-7,  Up: news-5-0-x

D.1.91 Changes in MySQL 5.0.6 (26 May 2005)
-------------------------------------------

*Functionality Added or Changed*

   * *Incompatible Change*: The behavior of *Note `LOAD DATA INFILE':
     load-data. and *Note `SELECT ... INTO OUTFILE': select. has
     changed when the `FIELDS TERMINATED BY' and `FIELDS ENCLOSED BY'
     values both are empty. Formerly, a column was read or written the
     display width of the column. For example, `INT(4)' was read or
     written using a field with a width of 4. Now columns are read and
     written using a field width wide enough to hold all values in the
     field. However, data files written before this change was made
     might not be reloaded correctly with *Note `LOAD DATA INFILE':
     load-data. for MySQL 4.1.12 and up. This change also affects data
     files read by *Note `mysqlimport': mysqlimport. and written by
     *Note `mysqldump --tab': mysqldump, which use *Note `LOAD DATA
     INFILE': load-data. and *Note `SELECT ... INTO OUTFILE': select.
     For more information, see *Note load-data::.  (Bug #12564)

   * *Incompatible Change*: `MyISAM' and `InnoDB' tables created with
     *Note `DECIMAL': numeric-types. columns in MySQL 5.0.3 to 5.0.5
     will appear corrupt after an upgrade to MySQL 5.0.6. Dump such
     tables with *Note `mysqldump': mysqldump.  before upgrading, and
     then reload them after upgrading. (The same incompatibility will
     occur for these tables created in MySQL 5.0.6 after a downgrade to
     MySQL 5.0.3 to 5.0.5.)  (Bug #10465, Bug #10625)

   * When the server cannot read a table because it cannot read the
     `.frm' file, print a message that the table was created with a
     different version of MySQL. (This can happen if you create tables
     that use new features and then downgrade to an older version of
     MySQL.)  (Bug #10435)

   * The *Note `GRANT': grant. and *Note `REVOKE': revoke. statements
     now support an OBJECT_TYPE clause to be used for disambiguating
     whether the grant object is a table, a stored procedure, or a
     stored function. Use of this clause requires that you upgrade your
     grant tables. See *Note mysql-fix-privilege-tables::.  (Bug #10246)

   * Added `REFERENCED_TABLE_SCHEMA', `REFERENCED_TABLE_NAME', and
     `REFERENCED_COLUMN_NAME' columns to the *Note `KEY_COLUMN_USAGE':
     key-column-usage-table. table of `INFORMATION_SCHEMA'.  (Bug #9587)

   * The use of `SESSION' or `GLOBAL' for user variables, or for local
     variables in stored routines, is no longer permitted.  (Bug #9286)

   * New `/*>' prompt for *Note `mysql': mysql. This prompt indicates
     that a `/* ... */' comment was begun on an earlier line and the
     closing `*/' sequence has not yet been seen.  (Bug #9186)

   * The *Note `INFORMATION_SCHEMA.SCHEMATA': schemata-table.  table
     now has a `DEFAULT_COLLATION_NAME' column.  (Bug #8998)

   * Added a `--show-warnings' option to *Note `mysql': mysql. to cause
     warnings to be shown after each statement if there are any. This
     option applies to interactive and batch mode. In interactive mode,
     `\w' and `\W' may be used to enable and disable warning display.
     (Bug #8684)

   * If strict SQL mode is enabled, *Note `VARCHAR': char. and *Note
     `VARBINARY': binary-varbinary. columns with a length greater than
     65,535 no longer are silently converted to *Note `TEXT': blob. or
     *Note `BLOB': blob. columns. Instead, an error occurs.  (Bug
     #8295, Bug #8296)

   * Removed a limitation that prevented use of FIFOs as logging
     targets (such as for the general query log). This modification
     _does not apply_ to the binary log and the relay log.  (Bug #8271)

   * *Note `SHOW VARIABLES': show-variables. now shows the
     `slave_compressed_protocol', `slave_load_tmpdir' and
     `slave_skip_errors' system variables.  (Bug #7800)

   * `InnoDB': When the maximum length of *Note `SHOW INNODB STATUS':
     show-innodb-status. output would be exceeded, truncate the
     beginning of the list of active transactions, instead of
     truncating the end of the output.  (Bug #5436)

   * Updated version of `libedit' to 2.9.  (Bug #2596)

   * `InnoDB': If `innodb_locks_unsafe_for_binlog' is enabled and the
     isolation level of the transaction is not set to `SERIALIZABLE',
     `InnoDB' uses a consistent read for select in clauses such as
     *Note `INSERT INTO ... SELECT': insert-select. and `UPDATE ...
     (SELECT)' that do not specify `FOR UPDATE' or `LOCK IN SHARE
     MODE'. Thus, no locks are set to rows read from selected table.

   * Added the `div_precision_increment' system variable, which
     indicates the number of digits by which to increase the scale of
     the result of division operations performed with the `/' operator.

   * Removed `mysqlshutdown.exe' and `mysqlwatch.exe' from the Windows
     `With Installer' distribution.

   * The precision of the *Note `DECIMAL': numeric-types. data type has
     been increased from 64 to 65 decimal digits.

   * Added the `--log-bin-trust-routine-creators' server option for
     setting the `log_bin_trust_routine_creators' system variable from
     the command line.

   * Implemented the `STMT_ATTR_PREFETCH_ROWS' option for the *Note
     `mysql_stmt_attr_set()': mysql-stmt-attr-set. C API function. This
     sets how many rows to fetch at a time when using cursors with
     prepared statements.

   * Added the `log_bin_trust_routine_creators' system variable, which
     applies when binary logging is enabled.  It controls whether
     stored routine creators can be trusted not to create stored
     routines that will cause unsafe events to be written to the binary
     log.

   * Removed unused system variable `myisam_max_extra_sort_file_size'.

   * Changed default value of `myisam_data_pointer_size' from 4 to 6.
     This enables us to avoid `table is full' errors for most cases.

   * Added a `--debug' option to *Note `my_print_defaults':
     my-print-defaults.

   * The variable `concurrent_insert' now takes 3 values. Setting this
     to 2 changes `MyISAM' to do concurrent inserts to end of table if
     table is in use by another thread.

*Bugs Fixed*

   * *Security Fix*: *Note `mysql_install_db': mysql-install-db.
     created the `mysql_install_db.X' file with a predictable file name
     and insecure permissions, which permitted local users to execute
     arbitrary SQL statements by modifying the file's contents.
     (CVE-2005-1636)

   * *Replication*: Statements that create and drop triggers were not
     being written to the binary log, which affects replication and
     data recovery options. Trigger-related statements now are logged,
     subject to the issues and limitations discussed in *Note
     stored-programs-logging::.  (Bug #10417)

   * *Replication*: Statements that create and use stored routines were
     not being written to the binary log, which affects replication and
     data recovery options. Stored routine-related statements now are
     logged, subject to the issues and limitations discussed in *Note
     stored-programs-logging::.  (Bug #2610)

   * `MERGE' tables could fail on Windows due to incorrect
     interpretation of path name separator characters for file names in
     the `.MRG' file.  (Bug #10687)

   * Repeated calls to `ABS()' when the argument evaluated to `NULL'
     crashed the server.  (Bug #10599)

   * `SELECT 0/0' returned `0' rather than `NULL'.  (Bug #10404)

   * *Note `INSERT ... ON DUPLICATE KEY UPDATE': insert-on-duplicate.
     with `MERGE' tables, which do not have unique indexes, caused the
     server to crash.  (Bug #10400)

   * `AUTO_INCREMENT' in `InnoDB' tables could assign the same value
     for several rows.  (Bug #10359)

   * *Note `mysqldump': mysqldump. crashed using the
     `--complete-insert' option while dumping tables with a large
     number of long column names.  (Bug #10286)

   * Incomplete results were returned from *Note
     `INFORMATION_SCHEMA.COLUMNS': columns-table. for
     `INFORMATION_SCHEMA' tables for non-`root' users.  (Bug #10261)

   * `mysql.cc' did not compile correctly using `VC++' on Windows.
     (Bug #10245)

   * Using `#pragma interface' or `#pragma implementation' in source
     files caused portability issues for `cygwin'.  (Bug #10241)

   * Corrected a problem where `DEFAULT' values were not assigned
     properly to `BIT(1)' or `CHAR(1)' columns if certain other columns
     preceded them in the table definition.  (Bug #10179)

   * The `BLACKHOLE' storage engine failed in testing, causing the
     server to crash.  (Bug #10175)

   * The optimizer was choosing suboptimal execution plans for certain
     outer joins where the right table of a left join (or left table of
     a right join) had both `ON' and `WHERE' conditions.  (Bug #10162)

   * Corrected a problem resolving outer column references in
     correlated subqueries when using the prepared statements.  (Bug
     #10041)

   * `INFORMATION_SCHEMA' tables were inaccessible depending on the
     lettercase used to refer to them.  (Bug #10018)

   * `awk' script portability problems were found in `
     `cmd-line-utils/libedit/makelist.sh' '.  (Bug #9954)

   * The error message for exceeding `MAX_CONNECTIONS_PER_HOUR'
     mistakenly referred to `max_connections'.  (Bug #9947)

   * *Note `RENAME TABLE': rename-table. for an `ARCHIVE' table failed
     if the `.arn' file was not present.  (Bug #9911)

   * A *Note `CHECK TABLE': check-table. statement whose arguments were
     a view name followed by a table name caused the server to crash.
     (Bug #9897)

   * *Note `my_print_defaults': my-print-defaults. was ignoring the
     `--defaults-extra-file' option or crashing when the option was
     given.  (Bug #9851, Bug #9136)

   * Within a stored procedure, attempting to update a view defined as
     an inner join failed with a `Table 'TBL_NAME' was locked with a
     READ lock and can't be updated' error.  (Bug #9841)

   * The *Note `INFORMATION_SCHEMA.COLUMNS': columns-table.  table was
     missing columns of views for which the user has access.  (Bug
     #9838)

   * Use of a *Note `CHAR': char. or *Note `VARCHAR': char. column with
     `MIN()' or `MAX()' and `GROUP BY ...  WITH ROLLUP' caused the
     server to crash.  (Bug #9820)

   * Usi `DISTINCT AVG()' with `GROUP BY ...  WITH ROLLUP' caused the
     server to crash.  (Bug #9800)

   * Using `AVG(DISTINCT)' with `GROUP BY ... WITH ROLLUP' caused the
     server to crash.  (Bug #9799)

   * Using `GROUP BY ... WITH ROLLUP' on an indexed column in an
     `InnoDB' table could cause the server to crash.  (Bug #9798)

   * Corrected some failures of prepared statements for SQL (*Note
     `PREPARE': prepare. plus *Note `EXECUTE': execute.) to return all
     rows for some *Note `SELECT': select. statements.  (Bug #9777, Bug
     #9096)

   * *Note `CREATE TABLE ... LIKE': create-table. did not work
     correctly when `lower_case_table_names' was set on a
     case-sensitive file system and the source table name was not given
     in lowercase.  (Bug #9761)

   * Corrected an inability to select from a view within a stored
     procedure.  (Bug #9758)

   * `net_read_timeout' and `net_write_timeout' were not being
     respected on Windows.  (Bug #9721)

   * `libsupc++' was longer required for building on FreeBSD 5.3.  (Bug
     #9714)

   * The *Note `mysql_stmt_attr_set()': mysql-stmt-attr-set. C API
     function now returns an error for option values that are defined
     in `mysql.h' but not yet implemented, such as
     `CURSOR_TYPE_SCROLLABLE'.  (Bug #9643)

   * Memory block allocation did not function correctly for the query
     cache in the embedded server.  (Bug #9549)

   * *Note `CREATE TABLE t AS SELECT UUID()': create-table-select.
     created a `VARCHAR(12)' column, which is too small to hold the
     36-character result from `UUID()'.  (Bug #9535)

   * *Note `SELECT DISTINCT': select. with a prepared statement that
     used a cursor could cause the server to crash.  (Bug #9520)

   * `NULL' key parts in hash indexes on *Note `VARCHAR': char. columns
     were not handled correctly, resulting in incorrect query results.
     (Bug #9489, Bug #10176)

   * The *Note `mysql_stmt_execute()': mysql-stmt-execute. and *Note
     `mysql_stmt_reset()': mysql-stmt-reset. C API functions now close
     any cursor that is open for the statement, which prevents a server
     crash.  (Bug #9478)

   * *Note `SELECT': select. from `INFORMATION_SCHEMA' tables failed if
     the statement has a `GROUP BY' clause and an aggregate function in
     the select list.  (Bug #9404)

   * `MAX()' for an `INT UNSIGNED' (unsigned 4-byte integer) column
     could return negative values if the column contained values larger
     than 2^31.  (Bug #9298)

   * Disabled binary logging within stored routines to avoid writing
     spurious extra statements to the binary log. For example, if a
     routine `p()' executes an *Note `INSERT': insert. statement, then
     for `CALL p()', the *Note `CALL': call. statement appears in the
     binary log, but not the *Note `INSERT': insert.  statement.  (Bug
     #9100)

   * `FORMAT()' now performs better rounding for double values (for
     example, `FORMAT(4.55,1)' returns `4.6', not `4.5').  (Bug #9060)

   * *Note `SHOW CREATE VIEW': show-create-view. got confused and could
     not find the view if there was a temporary table with the same
     name as the view.  (Bug #8921)

   * Selecting from a single-table view defined on multiple-table views
     caused a server crash.  (Bug #8528)

   * Remove extra slashes in `--tmpdir' value (for example, convert
     `/var//tmp' to `/var/tmp', because they caused various errors.
     (Bug #8497)

   * Invoking a stored function that executed a *Note `SHOW': show.
     statement resulted in a server crash.  (Bug #8408)

   * An error in the implementation of the `MyISAM' compression
     algorithm caused `myisampack' to fail with very large sets of data
     (total size of all the records in a single column needed to be at
     least 3 GB to trigger this issue).  (Bug #8321)

   * Added `Create_routine_priv', `Alter_routine_priv', and
     `Execute_priv' privileges to the `mysql.host' privilege table.
     (They had been added to `mysql.db' in MySQL 5.0.3 but not to the
     `host' table.)  (Bug #8166)

   * A deadlock resulted from using *Note `FLUSH TABLES WITH READ
     LOCK': flush. while an *Note `INSERT DELAYED': insert-delayed.
     statement was in progress.  (Bug #7823)

   * In strict SQL mode, some assignments to numeric columns that
     should have been rejected were not (such as the result of an
     arithmetic expression or an explicit `CAST()' operation).  (Bug
     #6961)

   * For `MERGE' tables, avoid writing absolute path names in the
     `.MRG' file for the names of the constituent `MyISAM' tables so
     that if the data directory is moved, `MERGE' tables will not
     break. For *Note `mysqld': mysqld, write just the `MyISAM' table
     name if it is in the same database as the `MERGE' table, and a path
     relative to the data directory otherwise. For the embedded
     servers, absolute path names may still be used.  (Bug #5964)

   * Multiple calls to a stored procedure that assigned the result of a
     subquery to a variable or compared it to a value with `IN' could
     cause the server to crash.  (Bug #5963)

   * If the file named by a `--defaults-extra-file' option does not
     exist or is otherwise inaccessible, an error now occurs.  (Bug
     #5056)

   * `configure' did not properly recognize whether NPTL was available
     on Linux.  (Bug #2173)


File: manual.info,  Node: news-5-0-5,  Next: news-5-0-4,  Prev: news-5-0-6,  Up: news-5-0-x

D.1.92 Changes in MySQL 5.0.5 (Not released)
--------------------------------------------

No public release of MySQL 5.0.5 was made. The changes described in
this section are available in MySQL 5.0.6.

*Functionality Added or Changed*

   * *MySQL Cluster*: More informative error messages are provided when
     a query is issued against an *Note `NDB': mysql-cluster. table that
     has been modified by another *Note `mysqld': mysqld. server.  (Bug
     #6762)

   * `InnoDB': When `foreign_key_checks = 0', *Note `ALTER TABLE':
     alter-table. and *Note `RENAME TABLE': rename-table. will ignore
     any type incompatibilities between referencing and referenced
     columns.  Thus, it will be possible to convert the character sets
     of columns that participate in a foreign key. Be sure to convert
     all tables before modifying any data!  (Bug #9802)

   * *Note `SHOW VARIABLES': show-variables. no longer displays the
     deprecated `log_update' system variable.  (Bug #9738)

   * Added support for the *Note `BIT': numeric-types. data type to the
     `MEMORY', `InnoDB', and `BDB' storage engines.

   * The behavior controlled by the `--innodb-fast-shutdown' option now
     can be changed at runtime by setting the value of the global
     `innodb_fast_shutdown' system variable. It now accepts values 0, 1
     and 2 (except on Netware where 2 is disabled). If set to 2, then
     when the MySQL server shuts down, `InnoDB' will just flush its logs
     and shut down brutally (and quickly) as if a MySQL crash had
     occurred; no committed transaction will be lost, but a crash
     recovery will be done at next startup.

*Bugs Fixed*

   * *Security Fix*: Starting *Note `mysqld': mysqld. with
     `--user=NON_EXISTENT_USER' caused it to run using the privileges
     of the account from which it was invoked, including the `root'
     account.  (Bug #9833)

   * A memory leak occurred when selecting from a view that contained a
     subquery.  (Bug #10107)

   * Setting the `storage_engine' system variable to `MEMORY'
     succeeded, but retrieving the variable resulted in a value of
     `HEAP' (the old name for the `MEMORY' storage engine) rather than
     `MEMORY'.  (Bug #10039)

   * Queries containing `CURRENT_USER()' incorrectly were registered in
     the query cache.  (Bug #9796)

   * Invoking a stored function that returned a value having an *Note
     `ENUM': enum. or *Note `SET': set. data type caused the server to
     crash.  (Bug #9775)

   * A string length comparison problem caused *Note `mysql': mysql. to
     fail when loading dump files containing certain escape sequences
     containing a backslash character (`\').  (Bug #9756)

   * After an internal temporary table became too large in memory and
     had to be converted to an on-disk table, the error indicator was
     not cleared and the query failed with error 1023 `Can't find
     record in '''.  (Bug #9703)

   * Use of a subquery that used `WITH ROLLUP' in the `FROM' clause of
     the main query sometimes resulted in a `Column cannot be null'
     error.  (Bug #9681)

   * `InnoDB': Assertion failures of types `ut_a(cursor->old_stored ==
     BTR_PCUR_OLD_STORED)' and `prebuilt->template_type == 0' could
     occur when performing multi-table updates. This bug was introduced
     in 4.1.10 and 4.0.24.  (Bug #9670)

   * A problem with `readline'caused the *Note `mysql': mysql. client
     to crash when the user pressed `Control+R'..  (Bug #9568)

   * Executing *Note `LOCK TABLES': lock-tables. and then calling a
     stored procedure caused an error and resulting in the server
     thinking that no stored procedures exist.  (Bug #9566)

   * The server died with signal 11 if a nonexistent location was
     specified for the location of the binary log. Now the server exits
     after printing an appropriate error message.  (Bug #9542)

   * Incorrect results were returned for queries of the form `SELECT
     ... LEFT JOIN ... WHERE EXISTS (SUBQUERY)', where the subquery
     selected rows based on an `IS NULL' condition.  (Bug #9516)

   * A segmentation fault in *Note `mysqlcheck': mysqlcheck. occurred
     when the last table checked in `--auto-repair' mode returned an
     error (such as the table being a `MERGE' table).  (Bug #9492)

   * Within a stored procedure, attempting to execute a multiple-table
     *Note `UPDATE': update. failed with a `Table 'TBL_NAME' was locked
     with a READ lock and can't be updated' error.  (Bug #9486)

   * *Note `mysqlshow': mysqlshow. displayed an incorrect row count for
     tables.  (Bug #9391)

   * `InnoDB': Next-key locking did not permit inserts which did not
     produce a `phantom'. If the range is of type `'a' <= uniquecolumn',
     `InnoDB' lock only the RECORD, if the record with the column value
     `'a'' exists in a CLUSTERED index. This enables inserts before a
     range.  (Bug #9354)

   * The optimizer did not compute the union of two ranges for the `OR'
     operator correctly.  (Bug #9348)

   * Corrected a failure to resolve a column reference correctly for a
     `LEFT JOIN' that compared a join column to an `IN' subquery.  (Bug
     #9338)

   * *Note `OPTIMIZE TABLE': optimize-table. was written twice to the
     binary log when used on `InnoDB' tables.  (Bug #9149)

   * Multiple-table updates could produce spurious data-truncation
     warnings if they used a join across columns that are indexed using
     a column prefix.  (Bug #9103)

   * Invocation of a stored function that returned a value having a
     *Note `BLOB': blob. data type caused the server to crash.  (Bug
     #9102)

   * For stored functions that should return a *Note `YEAR': year.
     value, corrected a failure of the value to be in *Note `YEAR':
     year.  format.  (Bug #8861)

   * Selecting from a view containing a subquery caused the server to
     hang.  (Bug #8490)

   * `TIMEDIFF()' with a negative time first argument and positive time
     second argument produced incorrect results.  (Bug #8068)

   * Invocation of a stored function that returned a value having a
     *Note `BIT': numeric-types. data type caused the server to crash.
     (Bug #7648)

   * `SET @var= CAST(NULL AS [INTEGER|CHAR])' now sets the result type
     of the variable to *Note `INTEGER': numeric-types./*Note `CHAR':
     char.  (Bug #6598)

   * The client/server protocol permitted the server to close the
     connection before sending the final error message. The problem
     could show up as a `Lost connection to MySQL server' error during
     a query when attempting to connect and access a nonexistent
     database.  (Bug #6387, Bug #9455)

   * Column references were not properly resolved when an outer join
     involving a view contained a subquery and the column was used both
     in the subquery and the outer query.  (Bug #6107, Bug #6106)

   * `InnoDB': Prevent *Note `ALTER TABLE': alter-table. from changing
     the storage engine if there are foreign key constraints on the
     table.  (Bug #5574, Bug #5670)


File: manual.info,  Node: news-5-0-4,  Next: news-5-0-3,  Prev: news-5-0-5,  Up: news-5-0-x

D.1.93 Changes in MySQL 5.0.4 (16 April 2005)
---------------------------------------------

*Functionality Added or Changed*

   * *Replication*: The way the time zone information is stored in the
     binary log was changed, so that it is now possible to have a
     replication master and slave running with different global time
     zones. A disadvantage is that replication from 5.0.4 masters to
     pre-5.0.4 slaves is impossible.

   * Added `ENGINE=MyISAM' table option when creating `mysql.proc'
     table in `mysql_create_system_tables' script to make sure the
     table is created as a `MyISAM' table even if the default storage
     engine has been changed.  (Bug #9496)

   * *Note `SHOW CREATE TABLE': show-create-table. for an
     `INFORMATION_SCHEMA' table no longer prints a `MAX_ROWS' value
     because the value has no meaning.  (Bug #8941)

   * Invalid `DEFAULT' values for *Note `CREATE TABLE': create-table.
     now generate errors.  (Bug #5903)

   * Added `--show-table-type' option to *Note `mysqlshow': mysqlshow,
     to display a column indicating the table type, as in *Note `SHOW
     FULL TABLES': show-tables.  (Bug #5036)

   * Support for MIT-pthreads was removed.

   * New configuration directives `!include' and `!includedir'
     implemented for including option files and searching directories
     for option files. See *Note option-files::, for usage.

   * Added `--with-big-tables' compilation option to `configure'.
     (Previously it was necessary to pass `-DBIG_TABLES' to the
     compiler manually to enable large table support.) See *Note
     source-configuration-options::, for details.

*Bugs Fixed*

   * *Security Fix*: Information in `INFORMATION_SCHEMA' could be
     exposed to a user with insufficient privileges.  (Bug #7214)

   * *MySQL Cluster*: The commit count cache for *Note `NDB':
     mysql-cluster. was not properly invalidated when deleting a record
     using a cursor.  (Bug #8585)

   * *Replication*: If, on a replication master, a *Note `LOAD DATA
     INFILE': load-data. operation was interrupted (by, for example, an
     integrity constraint violation or killed connection), the slave
     skipped the *Note `LOAD DATA INFILE': load-data. entirely, thus
     missing changes if this command permanently inserted or updated
     table records before being interrupted.  (Bug #3247)

   * *Note `mysql.server': mysql-server. no longer uses nonportable
     `alias' command or LSB functions.  (Bug #9852)

   * A server installed as a Windows service and started with
     `--shared-memory' could not be stopped.  (Bug #9665)

   * Selecting a *Note `BIT': numeric-types. column failed if the
     binary client/server protocol was used.  (Bug #9608)

   * Creating a `PRIMARY KEY' on a table having a *Note `BIT':
     numeric-types. column caused the server to crash.  (Bug #9571)

   * *Note `ENUM': enum. and *Note `SET': set. columns in `InnoDB'
     tables were treated incorrectly as character strings. This bug did
     not manifest itself with `latin1' collations, but it caused
     malfunction with `utf8'. Old tables will continue to work.  In new
     tables, *Note `ENUM': enum. and *Note `SET': set. will be stored
     internally as unsigned integers.  (Bug #9526)

   * An error in division of floating point numbers could cause nine
     zeros (`000000000') to be inserted in the middle of the quotient.
     (Bug #9501)

   * Fixed option-parsing code for the embedded server to understand
     `K', `M', and `G' suffixes for the `net_buffer_length' and
     `max_allowed_packet' options.  (Bug #9472)

   * Some user variables were not being handled with `implicit'
     coercibility.  (Bug #9425)

   * Using *Note `CREATE TABLE ... SELECT': create-table. or *Note
     `INSERT INTO ... SELECT': insert-select. to select from
     multiple-table view caused the server to crash.  (Bug #9398, Bug
     #8703)

   * Multiple executions of a prepared statement involving a join of an
     `INFORMATION_SCHEMA' table with another table could lead to a
     crash of the server.  (Bug #9383)

   * An `InnoDB' test suite failure was caused by a locking conflict
     between two server instances at server shutdown or startup. This
     conflict on advisory locks appears to be the result of a bug in
     the operating system; these locks should be released when the
     files are closed, but somehow that does not always happen
     immediately in Linux.  (Bug #9381)

   * Permit extra HKSCS and cp950 characters (`big5' extension
     characters) to be accepted in `big5' columns.  (Bug #9357)

   * The value of the `CHARACTER_MAXIMUM_LENGTH' and
     `CHARACTER_OCTET_LENGTH' columns of the *Note
     `INFORMATION_SCHEMA.COLUMNS': columns-table. table must be `NULL'
     for numeric columns, but were not.  (Bug #9344)

   * `INFORMATION_SCHEMA' tables had an implicit upper limit for the
     number of rows. As a result, not all data could be returned for
     some queries.  (Bug #9317)

   * `InnoDB': True *Note `VARCHAR': char.: `InnoDB' stored the
     'position' of a row wrong in a column prefix primary key index;
     this could cause MySQL to complain `ERROR 1032: Can't find record
     ...' in an update of the primary key, and also some `ORDER BY' or
     `DISTINCT' queries.  (Bug #9314)

   * `ORDER BY' sometimes caused incorrect sorting of `UTF8' data.
     (Bug #9309)

   * The `utf8_spanish2_ci' and `ucs2_spanish2_ci' collations no longer
     consider `r' equal to `rr' .  If you upgrade to this version from
     an earlier version, you should rebuild the indexes of any affected
     tables.  (Bug #9269)

   * *Note `CREATE OR REPLACE VIEW': create-view. and *Note `ALTER
     VIEW': alter-view. now require the `CREATE VIEW' and `DROP'
     privileges, not `CREATE VIEW' and `DELETE'.  (`DELETE' is a
     row-level privilege, not a table-level privilege.)  (Bug #9260)

   * Using `GROUP BY' on a decimal expression caused the server to
     crash.  (Bug #9210)

   * *Note `mysqldump': mysqldump. dumped core when invoked with
     `--tmp' and `--single-transaction' options and a nonexistent table
     name.  (Bug #9175)

   * Calling *Note `mysql_stmt_close()': mysql-stmt-close. for a
     single-row result set could cause the server to crash.  (Bug #9159)

   * Setting the `max_error_count' system variable to 0 resulted in a
     setting of 1.  (Bug #9072)

   * The use of `XOR' together with `NOT ISNULL()' erroneously resulted
     in some outer joins being converted to inner joins by the
     optimizer.  (Bug #9017)

   * Two prepared statements for single-row result sets being open
     simultaneously caused a `Commands out of sync error' error.  (Bug
     #8880)

   * Extraneous comparisons between `NULL' values in indexed columns
     were performed by the optimzer for operators such as `=' that are
     never true for `NULL'.  (Bug #8877)

   * In the client/server protocol for prepared statements,
     reconnection failed when the connection was killed with
     reconnection enabled.  (Bug #8866)

   * In prepared statements, subqueries containing parameters were
     erroneously treated as `const' tables during preparation,
     resulting in a server crash.  (Bug #8807)

   * Do not try to space-pad *Note `BLOB': blob.  columns containing
     `ucs2' characters.  (Bug #8771) This regression was introduced by
     Bug #7350.

   * The warning message from `GROUP_CONCAT()' did not always indicate
     the correct number of lines.  (Bug #8681)

   * `InnoDB': SQL statements were not rolled back on error.  (Bug
     #8650)

   * Too many rows were returned from queries that combined `ROLLUP'
     and `LIMIT' if `SQL_CALC_FOUND_ROWS' was given.  (Bug #8617)

   * Incorrect results were returned from queries that combined *Note
     `SELECT DISTINCT': select, `GROUP BY ', and `ROLLUP'.  (Bug #8616)

   * Queries that combined *Note `SELECT DISTINCT': select, `SUM()', and
     `ROLLUP' could cause the MySQL server to crash.  (Bug #8615)

   * The `tee' command could sometimes cause the *Note `mysql': mysql.
     client to crash.  (Bug #8499)

   * *Note `DROP TABLE': drop-table. did not drop triggers that were
     defined for the table. *Note `DROP DATABASE': drop-database. did
     not drop triggers in the database.  (Bug #6559, Bug #5859)

   * Added linking with `libsupc++' on Fedora Core 3 to get language
     support functions.  (Bug #6554)

   * Unions between binary and nonbinary columns failed due to a
     collation coercibility problem.  (Bug #6519)

   * Using `CONVERT('0000-00-00',DATE)' or `CAST('0000-00-00' as DATE)'
     with the `NO_ZERO_DATE' SQL mode enabled now produces a warning.
     (Bug #6145)

   * `TRADITIONAL' SQL mode should prevent inserts where a column with
     no default value is omitted or set to a value of `DEFAULT';
     however, in some cases, this restriction was not enforced.  (Bug
     #5986)

   * Inserting a zero date in a *Note `DATE': datetime, *Note
     `DATETIME': datetime. or *Note `TIMESTAMP': datetime. column during
     `TRADITIONAL' mode now produces an error.  (Bug #5933)

   * `CAST()' now produces warnings when casting incorrect *Note
     `INTEGER': numeric-types. and *Note `CHAR': char. values. This
     also applies to implicit `string' to `number' casts.  (Bug #5912)

   * An error now occurs if you try to insert an invalid value using a
     stored procedure in `STRICT' mode.  (Bug #5907)

   * `STR_TO_DATE()' now produces errors in strict mode (and warnings
     otherwise) when given an illegal argument.  (Bug #5902)

   * Inserting a zero date into a *Note `DATETIME': datetime. column in
     `TRADITIONAL' mode now produces an error.

   * *Note `ALTER TABLE': alter-table. now fails in `STRICT' mode if
     the alteration generates warnings.


File: manual.info,  Node: news-5-0-3,  Next: news-5-0-2,  Prev: news-5-0-4,  Up: news-5-0-x

D.1.94 Changes in MySQL 5.0.3 (23 March 2005 Beta)
--------------------------------------------------

*Note*:

This Beta release, as any other pre-production release, should not be
installed on `production' level systems or systems with critical data.
It is good practice to back up your data before installing any new
version of software. Although MySQL worked very hard to ensure a high
level of quality, protect your data by making a backup as you would for
any software beta release.

*Functionality Added or Changed*

   * *Incompatible Change*: The C API `ER_WARN_DATA_TRUNCATED' warning
     symbol was renamed to `WARN_DATA_TRUNCATED'.

   * *Incompatible Change*: The *Note `DECIMAL': numeric-types. and
     *Note `NUMERIC': numeric-types. data types now are handled with a
     fixed-point library that enables precision math handling that
     results in more accurate results. See *Note precision-math::.

     A consequence of the change in handling of the *Note `DECIMAL':
     numeric-types. and *Note `NUMERIC': numeric-types. fixed-point
     data types is that the server is more strict to follow standard
     SQL. For example, a data type of `DECIMAL(3,1)' stores a maximum
     value of 99.9. Previously, the server permitted larger numbers to
     be stored. That is, it stored a value such as 100.0 as 100.0. Now
     the server clips 100.0 to the maximum permissible value of 99.9.
     If you have tables that were created before MySQL 5.0.3 and that
     contain floating-point data not strictly legal for the data type,
     you should alter the data types of those columns. For example:

          ALTER TABLE TBL_NAME MODIFY COL_NAME DECIMAL(4,1);

     For user-defined functions, exact-value decimal arguments such as
     `1.3' or *Note `DECIMAL': numeric-types. column values were passed
     as `REAL_RESULT' values prior to MySQL 5.0.3.  As of 5.0.3, they
     are passed as strings with a type of `DECIMAL_RESULT'. If you
     upgrade to 5.0.3 and find that your UDF now receives string
     values, use the initialization function to coerce the arguments to
     numbers as described in *Note udf-arguments::.

     For the `FLOOR()' and `CEILING()' functions, the return type is no
     longer always *Note `BIGINT': numeric-types.  For exact-value
     numeric arguments, the return value has an exact-value numeric
     type. For string or floating-point arguments, the return value has
     a floating-point type.

   * *Replication*: *MySQL Cluster*: Added a new global system variable
     `slave_transaction_retries': If the replication slave SQL thread
     fails to execute a transaction because of an `InnoDB' deadlock or
     exceeded `InnoDB''s `innodb_lock_wait_timeout' or *Note
     `NDBCLUSTER': mysql-cluster.'s
     `TransactionDeadlockDetectionTimeout' or
     `TransactionInactiveTimeout', it automatically retries
     `slave_transaction_retries' times before stopping with an error.
     The default is 10.  (Bug #8325)

   * *MySQL Cluster*: When using this storage engine, the output of
     *Note `SHOW TABLE STATUS': show-table-status. now displays
     properly-calculated values in the `Avg_row_length' and
     `Data_length' columns. (Note that *Note `BLOB': blob. columns are
     not yet taken into account.) In addition, the number of replicas
     is now shown in the `Comment' column (as `number_of_replicas').

   * *Replication*: The *Note `LOAD DATA': load-data. statement was
     extended to support user variables in the target column list, and
     an optional `SET' clause. Now one can perform some transformations
     on data after they have been read and before they are inserted
     into the table. For example:

          LOAD DATA INFILE 'file.txt'
            INTO TABLE t1
            (column1, @var1)
            SET column2 = @var1/100;

     Also, replication of *Note `LOAD DATA': load-data.  was changed,
     so you can't replicate such statements from a 5.0.3 master to
     pre-5.0.3 slaves.

   * *Replication*: The way the character set information is stored
     into the binary log was changed, so that it is now possible to
     have a replication master and slave running with different global
     character sets. A disadvantage is that replication from 5.0.3
     masters to pre-5.0.3 slaves is impossible.

   * *Replication*: If the MySQL server is started without an argument
     to `--log-bin' and without `--log-bin-index', thus not providing a
     name for the binary log index file, a warning is issued because
     MySQL falls back to using the host name for that name, and this is
     prone to replication issues if the server's host name gets changed
     later.

   * Nonoptimal `index_merge' query execution plans were chosen on IRIX.
     (Bug #8578)

   * *Note `mysqld_safe': mysqld-safe. will create the directory where
     the UNIX socket file is to be located if the directory does not
     exist. This applies only to the last component of the directory
     path name.  (Bug #8513)

   * `ONLY_FULL_GROUP_BY' no longer is included in the `ANSI' composite
     SQL mode.  (Bug #8510)

   * The server now includes a timestamp in the `Ready for connections'
     message that is written to the error log at startup.  (Bug #8444)

   * *Note `CHECKSUM TABLE': checksum-table. returns a warning for
     nonexisting tables. The checksum value remains `NULL' as before.
     (Bug #8256)

   * Setting the connection collation to a value different from the
     server collation followed by a *Note `CREATE TABLE': create-table.
     statement that included a quoted default value resulted in a
     server crash.  (Bug #8235)

   * When a client releases a user-level lock, `DO RELEASE_LOCK()' will
     not be written to the binary log anymore (this makes the binary
     log smaller); as a counterpart, the slave does not actually take
     the lock when it executes `GET_LOCK()'. This is mainly an
     optimization and should not affect existing setups.  (Bug #7998)

   * `InnoDB': Corrected a bug in the crash recovery of
     `ROW_FORMAT=COMPACT' tables that caused corruption. There may
     still be bugs in the crash recovery, especially in `COMPACT'
     tables.  (Bug #7973)

   * Permitted the service-installation command for Windows servers to
     specify a single option other than `--defaults-file' following the
     service name. This is for compatibility with MySQL 4.1.  (Bug
     #7856)

   * Changed XML format for *Note `mysql': mysql. from
     `<COL_NAME>COL_VALUE</COL_NAME>' to `<field
     name="COL_NAME">COL_VALUE</field>' to enable proper encoding of
     column names that are not legal as element names.  (Bug #7811)

   * *Note `SHOW CREATE TABLE': show-create-table. now uses `USING
     INDEX_TYPE' rather than `TYPE INDEX_TYPE' to specify an index type.
     (Bug #7233)

   * `InnoDB': Implemented fast *Note `TRUNCATE TABLE': truncate-table.
     The old approach (deleting rows one by one) may be used if the
     table is being referenced by foreign keys.  (Bug #7150)

   * Out-of-order packets were sent (`ERROR' after `OK' or `EOF')
     following a *Note `KILL QUERY': kill.  statement.  (Bug #6804)

   * Added `sql_notes' session variable to cause `Note'-level warnings
     not to be recorded.  (Bug #6662)

   * Added *Note `mysql_library_init()': mysql-library-init. and *Note
     `mysql_library_end()': mysql-library-end. as synonyms for the
     *Note `mysql_server_init()': mysql-server-init. and *Note
     `mysql_server_end()': mysql-server-end. C API functions. *Note
     `mysql_library_init()': mysql-library-init.  and *Note
     `mysql_library_end()': mysql-library-end. are `#define' symbols,
     but the names more clearly indicate that they should be called
     when beginning and ending use of a MySQL C API library no matter
     whether the application uses `libmysqlclient' or `libmysqld'.
     (Bug #6149)

   * Added `VAR_POP()' and `STDDEV_POP()' as standard SQL aliases for
     the `VARIANCE()' and `STDDEV()' functions that compute population
     variance and standard deviation. Added new `VAR_SAMP()' and
     `STDDEV_SAMP()' functions to compute sample variance and standard
     deviation.  (Bug #3190)

   * `InnoDB': A commit is now performed after every 10,000 copied rows
     when executing *Note `ALTER TABLE': alter-table, *Note `CREATE
     INDEX': create-index, *Note `DROP INDEX': drop-index. or *Note
     `OPTIMIZE TABLE': optimize-table. This makes recovery from an
     aborted operations of these types much faster than previous to
     this change.

   * Added support for `AVG(DISTINCT)'.

   * A new `CREATE USER' privilege was added.

   * Support for `RAID' options in `MyISAM' tables has been removed. If
     you have tables that use these options, you should convert them
     before upgrading. See *Note upgrading-from-previous-series::.

   * `InnoDB': A shared record lock (`LOCK_REC_NOT_GAP') is now taken
     for a matching record in the foreign key check because inserts can
     be permitted into gaps.

   * The MySQL server now aborts when started with the option
     `--log-bin-index' and without `--log-bin', and when started with
     `--log-slave-updates' and without `--log-bin'.

   * API change: the `reconnect' flag in the `MYSQL' structure is now
     set to 0 by *Note `mysql_real_connect()': mysql-real-connect. Only
     those client programs which didn't explicitly set this flag to 0
     or 1 after *Note `mysql_real_connect()': mysql-real-connect.
     experience a change. Having automatic reconnection enabled by
     default was considered too dangerous (after reconnection, table
     locks, temporary tables, user and session variables are lost).

   * Bit-field values can be written using `b'VALUE'' notation.  VALUE
     is a binary value written using 0s and 1s.

   * `InnoDB': Relaxed locking in *Note `INSERT ... SELECT':
     insert-select, single table `UPDATE ...  (SELECT)' and single
     table `DELETE ...  (SELECT)' clauses when
     `innodb_locks_unsafe_for_binlog' is used and isolation level of
     the transaction is not `SERIALIZABLE'.  `InnoDB' uses consistent
     read in these cases for a selected table.

   * `InnoDB' now supports a fast *Note `TRUNCATE TABLE':
     truncate-table. One visible change from this is that
     auto-increment values for this table are reset on *Note `TRUNCATE
     TABLE': truncate-table.

   * `InnoDB': Introduced a compact record format that does not store
     the number of columns or the lengths of fixed-size columns. The
     old format can be requested by specifying `ROW_FORMAT=REDUNDANT'.
     The new format (`ROW_FORMAT=COMPACT') is the default.  The new
     format typically saves 20% of disk space and memory.

     The presence of the new compact row format decreases row storage
     space by about 20% at the cost of increasing CPU use for some
     operations. If your workload is a typical one that is limited by
     cache hit rates and disk speed it is likely to be faster. If it is
     a rare case that is limited by CPU speed, it might be slower.

   * From the Windows distribution, predefined accounts without
     passwords for remote users (`'root'@'%'', `''@'%'') were removed
     (other distributions never had them).

   * Added the `FEDERATED' storage engine. See *Note
     federated-storage-engine::.

   * User variable coercibility has been changed from `coercible' to
     `implicit.' That is, user variables have the same coercibility as
     column values.

   * Security improvement: User-defined functions should have at least
     one symbol defined in addition to the `xxx' symbol that
     corresponds to the main `xxx()' function. These auxiliary symbols
     correspond to the `xxx_init()', `xxx_deinit()', `xxx_reset()',
     `xxx_clear()', and `xxx_add()' functions. *Note `mysqld': mysqld.
     by default no longer loads UDFs unless they have at least one
     auxiliary symbol defined in addition to the main symbol. The
     `--allow-suspicious-udfs' option controls whether UDFs that have
     only an `xxx' symbol can be loaded. By default, the option is off.
     *Note `mysqld': mysqld. also checks UDF file names when it reads
     them from the `mysql.func' table and rejects those that contain
     directory path name separator characters. (It already checked
     names as given in *Note `CREATE FUNCTION': create-function.
     statements.) See *Note udf-calling::, *Note udf-aggr-calling::, and
     *Note udf-security::. Thanks to Stefano Di Paola
     <stefano.dipaola@wisec.it> for finding and informing us about this
     issue.  (CVE-2005-0709, CVE-2005-0710)

   * Added the `--large-pages' option for *Note `mysqld': mysqld. Large
     page support can be used on Linux systems. See *Note
     large-page-support::.

   * Added an `error' member to the `MYSQL_BIND' data structure that is
     used in the C API for prepared statements. This member is used for
     reporting data truncation errors. Truncation reporting is enabled
     using the new `MYSQL_REPORT_DATA_TRUNCATION' option for the *Note
     `mysql_options()': mysql-options. C API function.

   * Added the `multi_range_count' system variable.

   * The coercibility for the return value of functions such as
     `USER()' or `VERSION()' now is `system constant' rather than
     `implicit.' This makes these functions more coercible than column
     values so that comparisons of the two do not result in `Illegal
     mix of collations' errors.  `COERCIBILITY()' was modified to
     accommodate this new coercibility value. See *Note
     information-functions::.

   * `InnoDB': *Upgrading from 4.1:* The sorting order for end-space in
     *Note `TEXT': blob. columns for `InnoDB' tables has changed.
     Starting from 5.0.3, `InnoDB' compares *Note `TEXT': blob. columns
     as space-padded at the end. If you have a nonunique index on a
     *Note `TEXT': blob. column, you should run *Note `CHECK TABLE':
     check-table. on it, and run *Note `OPTIMIZE TABLE':
     optimize-table. if the check reports errors. If you have a `UNIQUE
     INDEX' on a *Note `TEXT': blob. column, you should rebuild the
     table with *Note `OPTIMIZE TABLE': optimize-table.

   * Boolean full-text phrase searching now requires only that matches
     contain exactly the same words as the phrase and in the same
     order. Nonword characters no longer need match exactly.

   * `my.cnf' in the compile-time datadir (usually
     `/usr/local/mysql/data/' in the binary tarball distributions) is
     not being read anymore. The value of the environment variable
     `MYSQL_HOME' is used instead of the hard-coded path.

   * Additional control over transaction completion was implemented.
     The *Note `COMMIT': commit. and *Note `ROLLBACK': commit.
     statements support `AND [NO] CHAIN' and `RELEASE' clauses. There
     is a new *Note `RELEASE SAVEPOINT': commit. statement. The
     `completion_type' system variable was added for setting the global
     and session default completion type.

   * Security improvement: The server creates `.frm', `.MYD', `.MYI',
     `.MRG', `.ISD', and `.ISM' table files only if a file with the
     same name does not already exist.  Thanks to Stefano Di Paola
     <stefano.dipaola@wisec.it> for finding and informing us about this
     issue.  (CVE-2005-0711)

   * Added the `engine_condition_pushdown' system variable. For NDB,
     setting this variable to 1 permits processing of some `WHERE'
     clause conditions to be processed in NDB nodes before rows are
     sent to the MySQL server, rather than having rows sent to the
     server for evaluation.

   * Support for the `ISAM' storage engine has been removed. If you
     have `ISAM' tables, you should convert them before upgrading. See
     *Note upgrading-from-previous-series::.

   * Added the `CREATE ROUTINE' and `ALTER ROUTINE' privileges, and
     made the `EXECUTE' privilege operational.

   * *Note `BIT': numeric-types. in column definitions now is a
     distinct data type; it no longer is treated as a synonym for
     `TINYINT(1)'.

   * Added `cp932' (SJIS for Windows Japanese) and `eucjpms' (UJIS for
     Windows Japanese) character sets.

   * `MEMORY' (`HEAP') can have *Note `VARCHAR': char. fields.

   * *Note `SHOW DATABASES': show-databases, *Note `SHOW TABLES':
     show-tables, *Note `SHOW COLUMNS': show-columns, and so forth,
     display information about the `INFORMATION_SCHEMA' database. Also,
     several *Note `SHOW': show. statements now accept a `WHERE' clause
     specifying which output rows to display. See *Note
     information-schema::.

   * *Note `SHOW COLUMNS': show-columns. now displays `NO' rather than
     blank in the `Null' output column if the corresponding table
     column cannot be `NULL'.

   * When the `MyISAM' storage engine detects corruption of a `MyISAM'
     table, a message describing the problem now is written to the
     error log.

   * A *Note `VARCHAR': char. column can now contain up to 65535 bytes.
     In addition, *Note `VARCHAR': char. columns now remember trailing
     spaces. For more details, see *Note news-5-0-x::.

     *Note*:

     If the table handler does not support the new *Note `VARCHAR':
     char. type, then it is converted to a *Note `CHAR': char. column.
     Currently this happens for *Note `NDB': mysql-cluster.  tables.

   * Added `--innodb-checksums' and `--innodb-doublewrite' options for
     *Note `mysqld': mysqld.

   * Added several `InnoDB' status variables. See *Note
     server-status-variables::.

   * Added account-specific `MAX_USER_CONNECTIONS' limit, which enables
     you to specify the maximum number of concurrent connections for
     the account. Also, all limited resources now are counted per
     account (instead of being counted per user + host pair as it was
     before). Use the `--old-style-user-limits' option to get the old
     behavior.

   * Implemented support for XA transactions. See *Note xa::. The
     implementation makes the `--innodb-safe-binlog' option obsolete,
     so it has been removed.

   * *Note `mysqlbinlog': mysqlbinlog. now prints a *Note `ROLLBACK':
     commit.  statement at the end of its output, in case the server
     crashed while it was in the process of writing the final entry
     into the last binary log named on the command line. This causes any
     half-written transaction to be rolled back when the output is
     executed. The *Note `ROLLBACK': commit. is harmless if the binary
     log file was written and closed normally.

   * `Seconds_Behind_Master' is `NULL' (which means `unknown') if the
     slave SQL thread is not running, or if the slave I/O thread is not
     running or not connected to master. It is zero if the SQL thread
     has caught up to the I/O thread. It no longer grows indefinitely
     if the master is idle.

   * *Note `FLUSH TABLES WITH READ LOCK': flush. is now killable while
     it is waiting for running *Note `COMMIT': commit. statements to
     finish.

   * The MySQL server aborts immediately instead of simply issuing a
     warning if it is started with the `--log-bin' option but cannot
     initialize the binary log at startup (that is, an error occurs
     when writing to the binary log file or binary log index file).

   * The binary log file and binary log index file now are handled the
     same way as `MyISAM' tables when there is a `disk full' or `quota
     exceeded' error.  See *Note full-disk::.

   * `InnoDB': When MySQL/InnoDB is compiled on Mac OS X 10.2 or
     earlier, detect the operating system version at run time and use
     the `fcntl()' file flush method on Mac OS X versions 10.3 and
     later. In Mac OS X, `fsync()' does not flush the write cache in
     the disk drive, but the special `fcntl()' does; however, the flush
     request is ignored by some external devices. Failure to flush the
     buffers may cause severe database corruption at power outages.

*Bugs Fixed*

   * *Replication*: If multiple semicolon-separated statements were
     received in a single packet, they were written to the binary log
     as a single event rather than as separate per-statement events.
     For a server serving as a replication master, this caused
     replication to fail when the event was sent to slave servers.
     (Bug #8436)

   * *Replication*: A replication master stamped a generated statement
     (such as a *Note `SET': set-option.  statement) with an error code
     intended only for another statement. This could happen, for
     example, when a statement generated a duplicate key error on the
     master but still had be to replicated to the slave.  (Bug #8412)

   * *Replication*: If the slave was running with `--replicate-*-table'
     options which excluded one temporary table and included another,
     and the two tables were used in a single `DROP TEMPORARY TABLE IF
     EXISTS' statement, as the ones the master automatically writes to
     its binary log upon client's disconnection when client has not
     explicitly dropped these, the slave could forget to delete the
     included replicated temporary table. Only the slave needs to be
     upgraded.  (Bug #8055)

   * *Replication*: Multiple-table updates did not replicate properly
     to slave servers where `--replicate-*-table' options had been
     specified.  (Bug #7011)

   * *Replication*: A replication slave could crash after replicating
     many *Note `ANALYZE TABLE': analyze-table, *Note `OPTIMIZE TABLE':
     optimize-table, or *Note `REPAIR TABLE': repair-table. statements
     from the master.  (Bug #6461, Bug #7658)

   * *Replication*: Changed semantics of `CREATE/ALTER/DROP DATABASE'
     statements so that replication of *Note `CREATE DATABASE':
     create-database. is possible when using `--binlog-do-db' and
     `--binlog-ignore-db'.  (Bug #6391)

   * *Replication*: DDL statements for views were not being written to
     the binary log (and thus not subject to replication).  (Bug #4838)

   * *Note `mysqldump': mysqldump. misinterpreted ``_'' and ``%''
     characters in the names of tables to be dumped as wildcard
     characters.  (Bug #9123)

   * In strict or traditional SQL mode, too-long string values assigned
     to string columns (*Note `CHAR': char, *Note `VARCHAR': char,
     *Note `BINARY': binary-varbinary, *Note `VARBINARY':
     binary-varbinary, *Note `TEXT': blob, or *Note `BLOB': blob.) were
     correctly truncated, but the server returned an SQLSTATE value of
     `01000' (should be `22001').  (Bug #9029, Bug #6999)

   * The definition of the enumeration-valued `sql_mode' column of the
     `mysql.proc' table was missing some of the current permissible SQL
     modes, so stored routines would not necessarily execute with the
     SQL mode in effect at the time of routine definition.  (Bug #8902)

   * *Note `TRUNCATE TABLE': truncate-table. did not work within stored
     procedures. Now, within stored procedures, *Note `TRUNCATE TABLE':
     truncate-table. is executed in the same way as *Note `DELETE':
     delete. This change was necessary because *Note `TRUNCATE TABLE':
     truncate-table. implicitly locks tables.  (Bug #8850)

   * A rare race condition could cause *Note `FLUSH TABLES WITH READ
     LOCK': flush. to hang.  (Bug #8682)

   * `AES_DECRYPT(COL_NAME,KEY)' could fail to return `NULL' for
     invalid values in COL_NAME, if COL_NAME was declared as `NOT NULL'.
     (Bug #8669)

   * If *Note `SELECT DISTINCT': select. named an index column multiple
     times in the select list, the server tried to access different key
     fields for each instance of the column, which could result in a
     crash.  (Bug #8532)

   * `MATCH ... AGAINST' in natural language mode could cause a server
     crash if the `FULLTEXT' index was not used in a join (that is,
     *Note `EXPLAIN': explain. did not show `fulltext' join mode) and
     the search query matched no rows in the table.  (Bug #8522)

   * *Note `REPAIR TABLE': repair-table. did not invalidate query
     results in the query cache that were generated from the table.
     (Bug #8480)

   * *Note `LOAD INDEX': load-index. statement now loads the index into
     memory.  (Bug #8452)

   * For a stored function that refers to a given table, invoking the
     function while selecting from the same table resulted in a server
     crash.  (Bug #8405)

   * Comparison of a *Note `DECIMAL': numeric-types. column containing
     `NULL' to a subquery that produced *Note `DECIMAL': numeric-types.
     values resulted in a server crash.  (Bug #8397)

   * `DELETE FROM TBL_NAME ...  WHERE ... ORDER BY TBL_NAME.COL_NAME '
     when the `ORDER BY' column was qualified with the table name
     caused the server to crash.  (Bug #8392)

   * Stored functions that used cursors could return incorrect results.
     (Bug #8386)

   * The Cyrillic letters `I' (_И_) and `SHORT I' (_Й_) were treated
     as being the same character by the `utf8_general_ci' collation.
     (Bug #8385)

   * When performing boolean full-text searches on `utf8' columns, a
     double-quote character in the search string caused the server to
     crash.  (Bug #8351)

   * The `--set-character-set' option for *Note `myisamchk': myisamchk.
     was changed to `--set-collation'. The value needed for specifying
     how to sort indexes is a collation name, not a character set name.
     (Bug #8349)

   * Corruption of `MyISAM' table indexes could occur with *Note
     `TRUNCATE TABLE': truncate-table. if the table had already been
     opened. For example, this was possible if the table had been
     opened implicitly by selecting from a `MERGE' table that mapped to
     the `MyISAM' table. The server now issues an error message for
     *Note `TRUNCATE TABLE': truncate-table. under these conditions.
     (Bug #8306)

   * For a query with both `GROUP BY' and `COUNT(DISTINCT)' clauses and
     a `FROM' clause with a subquery, `NULL' was returned for any *Note
     `VARCHAR': char. column selected by the subquery.  (Bug #8218)

   * Selecting from an `INFORMATION_SCHEMA' table combined with a
     subquery on an `INFORMATION_SCHEMA' table caused an error with the
     message `Table TBL_NAME is corrupted'.  (Bug #8164)

   * Matching of table names by *Note `mysqlhotcopy': mysqlhotcopy. now
     accommodates `DBD::mysql' versions 2.9003 and up, which implement
     identifier quoting.  (Bug #8136)

   * Re-execution of prepared statements containing subqueries caused
     the server to crash.  (Bug #8125)

   * A problem with equality propagation optimization for prepared
     statements and stored procedures caused a server crash upon
     re-execution of the prepared statement or stored procedure.  (Bug
     #8115, Bug #8849) See also Bug #51650.

   * Selecting from a view defined as a join caused a server crash if
     the query cache was enabled.  (Bug #8054)

   * Results in the query cache generated from a view were not properly
     invalidated after *Note `ALTER VIEW': alter-view. or *Note `DROP
     VIEW': drop-view. on that view.  (Bug #8050)

   * Creating a table using a name containing a character that is
     illegal in `character_set_client' resulted in the character being
     stripped from the name and no error. The character now is
     considered an error.  (Bug #8041)

   * Certain correlated subqueries with forward references (referring
     to an alias defined later in the outer query) could crash the
     server.  (Bug #8025)

   * Corrected a problem with references to `DUAL' where statements
     such as `SELECT 1 AS a FROM DUAL' would succeed but statements
     such as `SELECT 1 AS a FROM DUAL LIMIT 1' would fail.  (Bug #8023)

   * Comparing a nested row expression (such as `ROW(1,(2,3))') with a
     subquery caused the server to crash.  (Bug #8022)

   * The number of columns in a row comparison against a subquery was
     calculated incorrectly.  (Bug #8020)

   * *Note `mysqldump': mysqldump. now avoids writing `SET NAMES' to
     the dump output if the server is older than version 4.1 and would
     not understand that statement.  (Bug #7997)

   * A deadlock could occur on an update followed by a *Note `SELECT':
     select. on an `InnoDB' table without any explicit locks being
     taken. `InnoDB' now takes an exclusive lock when `INSERT ON
     DUPLICATE KEY UPDATE' is checking duplicate keys.  (Bug #7975)

   * A slave running MySQL 3.23.51 or newer hung while trying to
     connect to a master running MySQL 3.23.50 or older. (This occurred
     due to a bug in the old masters--`SELECT @@UNKNOWN_VAR' caused the
     server to hang--which was fixed in MySQL 3.23.50.)  (Bug #7965)

   * Erroneous output resulted from *Note `SELECT DISTINCT': select.
     combined with a subquery and `GROUP BY'.  (Bug #7946)

   * `FOUND_ROWS()' returned an incorrect value after a `SELECT
     SQL_CALC_FOUND_ROWS DISTINCT' statement that selected constants and
     included `GROUP BY' and `LIMIT' clauses.  (Bug #7945)

   * *Note `mysqld_safe': mysqld-safe. now understands the `--help'
     option. Previously, it ignored the option and attempted to start
     the server anyway.  (Bug #7931)

   * Creating a user with grants failed when specifying a password but
     worked without one.  (Bug #7905)

   * Comparing the result of a subquery to a nonexistent column caused
     the server to crash. This issue affected MySQL on Windows
     platforms only.  (Bug #7885)

   * *Note `ALTER TABLE': alter-table. improperly accepted an index on
     a *Note `TIMESTAMP': datetime. column that *Note `CREATE TABLE':
     create-table. would reject.  (Bug #7884)

   * MySQL permitted concurrent updates (including inserts and deletes)
     to a table if binary logging was enabled. Now, all updates are
     executed in a serialized fashion, because they are executed
     serialized when the binary log is replayed.  (Bug #7879)

   * Ensured that *Note `mysqldump --single-transaction': mysqldump.
     sets its transaction isolation level to `REPEATABLE READ' before
     proceeding (otherwise if the MySQL server was configured to run
     with a default isolation level lower than `REPEATABLE READ' it
     could give an inconsistent dump).  (Bug #7850)

   * *Note `mysqlbinlog': mysqlbinlog. forgot to add backquotes around
     the collation of user variables (causing later parsing problems as
     `BINARY' is a reserved word).  (Bug #7793)

   * A `Table is full' error occurred when the table was still smaller
     than `max_heap_table_size'.  (Bug #7791)

   * Use of `GROUP_CONCAT()' with `HAVING' caused the server to crash.
     (Bug #7769)

   * The `CONV()' function returned an unsigned *Note `BIGINT':
     numeric-types. number, which does not fit in 32 bits.  (Bug #7751)

   * The `IN()' operator did not return correct results if all values
     in the list were constants and some of them used substring
     functions such as `LEFT()', `RIGHT()', or `MID()'.  (Bug #7716)

   * When encountering a `disk full' or `quota exceeded' write error,
     `MyISAM' sometimes failed to sleep and retry the write, resulting
     in a corrupted table.  (Bug #7714)

   * The `CONVERT_TZ()' function, when its second or third argument was
     from a `const' table, caused the server to crash. (See *Note
     explain::.)  (Bug #7705)

   * The output of the `STATUS' (`\s') command in *Note `mysql': mysql.
     had the values for the server and client character sets reversed.
     (Bug #7571)

   * A `LEFT OUTER JOIN' between an empty base table and a view on an
     empty base table caused a server crash.  (Bug #7433)

   * Ordering by an unsigned expression (more complex than a column
     reference) was treating the value as signed, producing incorrectly
     sorted results. `HAVING' was also treating unsigned columns as
     signed.  (Bug #7425)

   * The server crashed when an error occurred during the filling of a
     temporary table created for handling a view or derived table.
     (Bug #7413)

   * Made the MySQL server accept executing *Note `SHOW CREATE
     DATABASE': show-create-database. even if the connection has an open
     transaction or locked tables. Refusing it made *Note `mysqldump
     --single-transaction': mysqldump. sometimes fail to print a
     complete *Note `CREATE DATABASE': create-database. statement for
     some dumped databases.  (Bug #7358)

   * Handling of trailing spaces was incorrect for the `ucs2' character
     set.  (Bug #7350)

   * `--expire-logs-days' was not honored if using only transactions.
     (Bug #7236)

   * Some `INFORMATION_SCHEMA' columns that contained timestamp values
     were of type *Note `VARBINARY': binary-varbinary. These were
     changed to *Note `TIMESTAMP': datetime.  (Bug #7217)

   * Some `INFORMATION_SCHEMA' columns that contained catalog
     identifiers were of type *Note `LONGTEXT': blob. These were
     changed to `VARCHAR(N', where N is the appropriate maximum
     identifier length.  (Bug #7215)

   * Use of `GROUP_CONCAT()' in the select list when selecting from a
     view caused a server crash.  (Bug #7116)

   * An expression that tested a case-insensitive character column
     against string constants that differed in lettercase could fail
     because the constants were treated as having a binary collation.
     (For example, `WHERE city='London' AND city='london'' could fail.)
     (Bug #7098, Bug #8690)

   * Setting the initial `AUTO_INCREMENT' value for an `InnoDB' table
     using *Note `CREATE TABLE ... AUTO_INCREMENT = N': create-table.
     did not work, and *Note `ALTER TABLE ... AUTO_INCREMENT = N':
     alter-table. did not reset the current value.  (Bug #7061)

   * When setting integer system variables to a negative value with
     `SET VARIABLES', the value was treated as a positive value modulo
     2^32.  (Bug #6958)

   * Use of a view in a correlated subquery that contains `HAVING' but
     no `GROUP BY' caused a server crash.  (Bug #6894)

   * Praparing a query using the `CONVERT_TZ()' function with constant
     arguments caused the server to crash.  (Bug #6849)

   * Handling by *Note `mysql_list_fields()': mysql-list-fields.  of
     references to stored functions within views was incorrect and
     could result in a server crash.  (Bug #6814)

   * A sequence of *Note `BEGIN': commit. (or `SET autocommit = 0'),
     *Note `FLUSH TABLES WITH READ LOCK': flush, transactional update,
     *Note `COMMIT': commit, *Note `FLUSH TABLES WITH READ LOCK':
     flush. could hang the connection forever and possibly the MySQL
     server itself. This happened for example when running the
     `innobackup' script several times.  (Bug #6732)

   * Prevent adding *Note `CREATE TABLE .. SELECT':
     create-table-select. query to the binary log when the insertion of
     new records partially failed.  (Bug #6682)

   * *Note `mysqlbinlog': mysqlbinlog. did not print `SET
     PSEUDO_THREAD_ID' statements in front of *Note `LOAD DATA INFILE':
     load-data. statements inserting into temporary tables, thus
     causing potential problems when rolling forward these statements
     after restoring a backup.  (Bug #6671)

   * If a `MyISAM' table on Windows had `INDEX DIRECTORY' or `DATA
     DIRECTORY' table options, *Note `mysqldump': mysqldump.  dumped
     the directory path names with single-backslash path name
     separators. This would cause syntax errors when importing the dump
     file. *Note `mysqldump': mysqldump. now changes ``\'' to ``/'' in
     the path names on Windows.  (Bug #6660)

   * *Note `SHOW CREATE TABLE': show-create-table. now reports
     `ENGINE=MEMORY' rather than `ENGINE=HEAP' for a `MEMORY' table
     (unless the `MYSQL323' SQL mode is enabled).  (Bug #6659)

   * Incorrectly ordered results were returned from a query using a
     `FULLTEXT' index to retrieve rows and there was another index that
     was usable for `ORDER BY'.  For such a query, *Note `EXPLAIN':
     explain. showed the `fulltext' join type, but showed the other
     (not `FULLTEXT') index in the `Key' column.  (Bug #6635)

   * *Note `CREATE TABLE ... LIKE': create-table. failed on Windows
     when the source or destination table was located in a symlinked
     database directory.  (Bug #6607)

   * Retrieving from a view defined as a *Note `SELECT': select. that
     mixed *Note `UNION ALL': union. and *Note `UNION DISTINCT': union.
     resulted in a different result than retrieving from the original
     *Note `SELECT': select.  (Bug #6565)

   * Selecting from a view that had an `EXISTS' or `NOT EXISTS'
     subquery did not always work properly, and selecting columns by
     name could cause a server crash. With `SELECT *', crashes did not
     occur, but columns in the outer query were not resolved properly.
     (Bug #6394)

   * Fixed a problem in `NO_BACKSLASH_ESCAPES' SQL mode for strings
     that contained both the string quoting character and backslash.
     (Bug #6368)

   * The `CHAR()' function was not ignoring `NULL' arguments, contrary
     to the documentation.  (Bug #6317)

   * Starting and stopping the slave thread (only) could in some
     circumstance cause the server to crash.  (Bug #6148)

   * `InnoDB': Honor the `--tmpdir' startup option when creating
     temporary files. Previously, `InnoDB' temporary files were always
     created in the temporary directory of the operating system. On
     Netware, `InnoDB' will continue to ignore `--tmpdir'.  (Bug #5822)

   * A `HAVING' clause that referred to `RAND()' or a user-defined
     function in the *Note `SELECT': select. part of a query through an
     alias could cause MySQL to crash or to return an incorrect value.
     (Bug #5185)

   * Platform and architecture information in version information
     produced for `--version' option on Windows was always `Win95/Win98
     (i32)'. More accurately determine platform as `Win32' or `Win64'
     for 32-bit or 64-bit Windows, and architecture as `ia32' for x86,
     `ia64' for Itanium, and `axp' for Alpha.  (Bug #4445)

   * When using the `RPAD()' function (or any function adding spaces to
     the right) in a query that had to be resolved by using a temporary
     table, all resulting strings had rightmost spaces removed (that is,
     `RPAD()' did not work) (Bug #4048)

   * Host name matching didn't work if a netmask was specified for
     table-specific privileges.  (Bug #3309)

   * `mysql_fix_privilege_tables' now makes it possible for `mysql'
     privilege tables created in MySQL 5.0 to be used with MySQL 4.1.
     This makes it possible to downgrade from 5.0 to 4.1, or to run
     MySQL 4.1 and 5.0 using the same privilege table files for testing
     purposes.

   * Giving *Note `mysqld': mysqld. a `SIGHUP' caused it to crash.

   * Prepared statements using `SUM(DISTINCT...)' did not perform
     correctly.

   * `InnoDB': Use native `tmpfile()' function on Netware. All `InnoDB'
     temporary files are created under `sys:\tmp'. Previously, `InnoDB'
     temporary files were never deleted on Netware.

   * A symlink vulnerability in the *Note `mysqlaccess': mysqlaccess.
     script was reported by Javier Fernandez-Sanguino Pena and Debian
     Security Audit Team (http://www.debian.org/security/audit).
     (CVE-2005-0004)

   * A number of portability issues relating to overflow in floating
     point values were corrected.

   * Prepared statements now gives warnings on prepare.

   * The combination of `-not' and `trunc*' operators in a full-text
     search did not work correctly. Using more than one truncated
     negative search term caused the result to be empty.

   * Prepared statements did not work correctly with `OUTER JOIN'.


File: manual.info,  Node: news-5-0-2,  Next: news-5-0-1,  Prev: news-5-0-3,  Up: news-5-0-x

D.1.95 Changes in MySQL 5.0.2 (01 December 2004)
------------------------------------------------

*Functionality Added or Changed*

   * *Incompatible Change*: The precedence of `NOT' operator has
     changed so that expressions such as `NOT a BETWEEN b AND c' are
     parsed correctly as `NOT (a BETWEEN b AND c)' rather than as `(NOT
     a) BETWEEN b AND c'. The pre-5.0 higher-precedence behavior can be
     obtained by enabling the new `HIGH_NOT_PRECEDENCE' SQL mode.

   * *Incompatible Change*: *Note `SHOW STATUS': show-status. now shows
     the session (thread-specific) status variables and *Note `SHOW
     GLOBAL STATUS': show-status. shows the status variables for the
     whole server.

     Before MySQL 5.0.2, *Note `SHOW STATUS': show-status.  returned
     global status values. Because the default as of 5.0.2 is to return
     session values, this is incompatible with previous versions. To
     issue a *Note `SHOW STATUS': show-status.  statement that will
     retrieve global status values for all versions of MySQL, write it
     like this:

          SHOW /*!50002 GLOBAL */ STATUS;

   * *Replication*: *Note `mysqldump `--single-transaction
     --master-data'': mysqldump. is now able to take an online
     (nonblocking) dump of `InnoDB' and report the corresponding binary
     log coordinates, which makes a backup suitable for point-in-time
     recovery, roll-forward or replication slave creation. See *Note
     mysqldump::.

   * *Replication*: Two new system variables were introduced.
     `auto_increment_increment' and `auto_increment_offset' can be set
     locally or globally, and are intended for use in controlling the
     behavior of `AUTO_INCREMENT' columns in master-to-master
     replication. Note that these variables are not intended to take
     the place of sequences. See *Note server-system-variables::.

   * If a write to a `MyISAM' table fails because of a full disk or an
     exceeded disk quota, it now prints a message to the error log
     every 10 minutes, and waits until disk space becomes available.
     (Bug #3248)

   * Made the MySQL server ignore `SIGHUP' and `SIGQUIT' on Mac OS X
     10.3. This is needed because under this OS, the MySQL server
     receives lots of these signals.  (Bug #2030)

   * If the server finds that the `user' table has not been upgraded to
     include the view-related privilege columns, it treats each account
     as having view privileges that are the same as its `CREATE'
     privilege.

   * A connection doing a rollback now displays "Rolling back" in the
     `State' column of *Note `SHOW PROCESSLIST': show-processlist.

   * Renamed the `sql_updatable_view_key' system variable to
     `updatable_views_with_limit'.  This variable now can have only two
     values:

        * `1' or `YES': Don't issue an error message (warning only) if
          a VIEW without presence of a key in the underlying table is
          used in queries with a `LIMIT' clause for updating. (This is
          the default value.)

        * `0' or `NO': Prohibit update of a VIEW, which does not
          contain a key in the underlying table and the query uses a
          `LIMIT' clause (usually get from GUI tools).

   * Reverted output format of *Note `SHOW TABLES': show-tables. to old
     pre-5.0.1 format that did not include a table type column. To get
     the additional column that lists the table type, use *Note `SHOW
     FULL TABLES': show-tables. now.

   * *Note `CHECK TABLE': check-table. now works for views.

   * Modify *Note `DROP USER': drop-user. so that it drops the account,
     including all its privileges. Formerly, it removed the account
     record only for an account that had all privileges revoked.

   * `0' or `NO': Prohibit update of a VIEW, which does not contain a
     key in the underlying table and the query uses a `LIMIT' clause
     (usually get from GUI tools).

   * We now detect too-large floating point numbers during statement
     parsing and generate an error messages for them.

   * New `auto_increment_increment' and `auto_increment_offset' system
     variables. These enable you to set up a server to generate
     auto-increment values that don't conflict with another server.

   * Added the *Note `CREATE USER': create-user. and *Note `RENAME
     USER': rename-user. statements.

   * MySQL now by default checks dates and in strict mode permits only
     fully correct dates. If you want MySQL to behave as before, you
     should enable the new `ALLOW_INVALID_DATES' SQL mode.

   * Added `NO_AUTO_CREATE_USER' SQL mode to prevent *Note `GRANT':
     grant. from automatically creating new users if it would otherwise
     do so, unless a password also is specified.

   * MySQL now remembers which columns were declared to have default
     values. In `STRICT_TRANS_TABLES'/`STRICT_ALL_TABLES' mode, you now
     get an error if you do an *Note `INSERT': insert. without
     specifying all columns that don't have a default value. A side
     effect of this is that when you do `SHOW CREATE' for a new table,
     you no longer see a `DEFAULT' value for a column for which you
     didn't specify a default value.

   * `InnoDB': If you specify the `innodb_locks_unsafe_for_binlog'
     option in `my.cnf', for an *Note `UPDATE': update. or a *Note
     `DELETE': delete, `InnoDB' locks only the rows that it updates or
     deletes. This greatly reduces the probability of deadlocks.

   * A `HAVING' clause in a *Note `SELECT': select. statement now can
     refer to columns in the `GROUP BY' clause, as required by standard
     SQL.

   * The `SCHEMA' and `SCHEMAS' keywords are now accepted as synonyms
     for `DATABASE' and `DATABASES'.

   * Added several `InnoDB' status variables. See *Note
     server-status-variables::.

   * Added `STRICT_TRANS_TABLES', `STRICT_ALL_TABLES',
     `NO_ZERO_IN_DATE', `NO_ZERO_DATE', `ERROR_FOR_DIVISION_BY_ZERO',
     and `TRADITIONAL' SQL modes. The `TRADITIONAL' mode is shorthand
     for all the preceding modes. When using mode `TRADITIONAL', MySQL
     generates an error if you try to insert a wrong value in a column.
     It does not adjust the value to the closest possible legal value.

   * The *Note `mysql_fix_privilege_tables':
     mysql-fix-privilege-tables. script now initializes the global
     `CREATE VIEW' and `SHOW VIEW' privileges in the `user' table to
     the value of the `CREATE' privilege in that table.

   * `1' or `YES': Don't issue an error message (warning only) if a
     VIEW without presence of a key in the underlying table is used in
     queries with a `LIMIT' clause for updating. (This is the default
     value.)

   * The compilation flag `DONT_USE_DEFAULT_FIELDS' was removed because
     you can get the same behavior by setting the `sql_mode' system
     variable to `STRICT_TRANS_TABLES'.

   * *Note `mysqlbinlog': mysqlbinlog. now prints an informative
     commented line (thread id, timestamp, server id, and so forth)
     before each *Note `LOAD DATA INFILE': load-data, like it does for
     other queries; unless `--short-form' is used.

   * Added `IS [NOT] BOOLEAN_VALUE ' syntax, where BOOLEAN_VALUE is
     `TRUE', `FALSE', or `UNKNOWN'.

   * Added `--start-datetime', `--stop-datetime', `--start-position',
     and `--stop-position' options to `mysqlbinlog'. These make
     point-in-time recovery easier.

   * Added initial support for rudimentary triggers (the *Note `CREATE
     TRIGGER': create-trigger. and *Note `DROP TRIGGER': drop-trigger.
     statements).

   * Added basic support for read-only server side cursors.

   * Implemented the `WITH CHECK OPTION' clause for *Note `CREATE
     VIEW': create-view.

   * Added support for the `INFORMATION_SCHEMA' `information database'
     that provides database metadata. See *Note information-schema::.

*Bugs Fixed*

   * *Replication*: A problem introduced in MySQL 4.0.21 caused
     replication slaves to stop (error 1223) where a connection started
     a transaction, performed updates, then issued a *Note `FLUSH
     TABLES WITH READ LOCK': flush. followed by a *Note `COMMIT':
     commit. This issue occurred when using the `InnoDB' `innobackup'
     script.  (Bug #5949)

   * *Replication*: *Note `SET COLLATION_SERVER...': set-option.
     statements replicated by the slave SQL thread no longer advance
     its position. This is so that, if the thread is interrupted before
     the update is completed, it later performs the *Note `SET':
     set-option. again.  (Bug #5705)

   * *Replication*: *Note `OPTIMIZE TABLE': optimize-table, *Note
     `REPAIR TABLE': repair-table, and *Note `ANALYZE TABLE':
     analyze-table. are now replicated without any error code in the
     binary log.  (Bug #5551)

   * *Replication*: A *Note `CREATE TABLE ... TYPE=HEAP ... AS
     SELECT...': create-table-select. statement caused the replication
     slave to stop.  (Bug #4971)

   * *Note `mysqlbinlog': mysqlbinlog. was unable to read from `stdin',
     for example, when piping the output from `zcat' to *Note
     `mysqlbinlog': mysqlbinlog.  (Bug #7853)

   * If a connection was interrupted by a network error and did a
     rollback, the network error code got stored into the *Note
     `BEGIN': commit. and *Note `ROLLBACK': commit.  binary log events;
     that caused superfluous slave stops.  (Bug #6522)

   * If a connection had an open transaction but had done no updates to
     transactional tables (for example if had just done a `SELECT FOR
     UPDATE' then executed a nontransactional update, that update
     automatically committed the transaction (thus releasing `InnoDB''s
     row-level locks etc).  (Bug #5714)

   * If the slave SQL thread finds a syntax error in a query (which
     should be rare, as the master parsed it successfully), it now
     stops immediately.  (Bug #5711)

   * `disable-local-infile' option had no effect if the client read it
     from a configuration file using *Note
     `mysql_options(...,MYSQL_READ_DEFAULT,...)': mysql-options.  (Bug
     #5073)

   * `SET GLOBAL SYNC_BINLOG' did not work on some platforms (Mac OS X).
     (Bug #5064)

   * `mysql-test-run' failed the `rpl_trunc_binlog' test when running
     the test from the installation directory.  (Bug #5050)

   * *Note `mysql_options(...,MYSQL_OPT_LOCAL_INFILE,...)':
     mysql-options.  failed to disable *Note `LOAD DATA LOCAL INFILE':
     load-data.  (Bug #5038)

   * The counter for an `AUTO_INCREMENT' column was not reset by *Note
     `TRUNCATE TABLE': truncate-table. if the table was a temporary one.
     (Bug #5033)

   * *Note `FLUSH TABLES WITH READ LOCK': flush. now blocks *Note
     `COMMIT': commit.  statements if the server is running with binary
     logging enabled; this ensures that the binary log position is
     trustable when doing a full backup of tables and the binary log.
     (Bug #4953)

   * *Note `KILL': kill.ing a connection while it was performing *Note
     `START SLAVE': start-slave. caused the server to crash.  (Bug
     #4827)

   * A deadlock could happen under certain rare circumstances when
     using *Note `KILL': kill.  (Bug #4810)

   * `mysql-test-run' failed the `grant_cache' test when run as Unix
     root user.  (Bug #4678)

   * *Note `mysqlbinlog --read-from-remote-server': mysqlbinlog.
     sometimes could not accept 2 binary logs in a single invocation.
     (Bug #4507)

   * *Note `mysqlbinlog --position --read-from-remote-server':
     mysqlbinlog. had incorrect output for `# at LOG_POS'.  (Bug #4506)


File: manual.info,  Node: news-5-0-1,  Next: news-5-0-0,  Prev: news-5-0-2,  Up: news-5-0-x

D.1.96 Changes in MySQL 5.0.1 (27 July 2004)
--------------------------------------------

*Note*:

This build passes our test suite and fixes a lot of reported bugs found
in the previous 5.0.0 release. However, please be aware that this is
not a `standard MySQL build' in the sense that there are still some
open critical bugs in our bugs database at `http://bugs.mysql.com/' that
affect this release as well. We are actively fixing these and will make
a new release where these are fixed as soon as possible. However, this
binary should be a good candidate for testing new MySQL 5.0 features
for future products.

*Functionality Added or Changed*

   * *Incompatible Change*: C API change: *Note `mysql_shutdown()':
     mysql-shutdown.  now requires a second argument. This is a
     source-level incompatibility that affects how you compile client
     programs; it does not affect the ability of compiled clients to
     communicate with older servers. See *Note mysql-shutdown::.

   * *Replication*: For replication of `MEMORY' (`HEAP') tables: Made
     the master automatically write a `DELETE FROM' statement to its
     binary log when a `MEMORY' table is opened for the first time
     since the master's startup. This is for the case where the slave
     has replicated a nonempty `MEMORY' table, and then the master is
     shut down and restarted: the table is now empty on the master; the
     `DELETE FROM' empties it on the slave as well.

     Even with this fix, between the master's restart and the first use
     of the table on master, the slave still has out-of-date data in
     the table. However, if you use the `--init-file' option to populate
     the `MEMORY' table on the master at startup, it ensures that the
     failing time interval is zero.  (Bug #2477)

   * *Replication*: Added the `--replicate-same-server-id' server
     option.

   * *Replication*: `DROP DATABASE IF EXISTS', `DROP TABLE IF EXISTS',
     single-table *Note `DELETE': delete, and single-table *Note
     `UPDATE': update. now are written to the binary log even if they
     changed nothing on the master (for example, even if a *Note
     `DELETE': delete. matched no rows). The old behavior sometimes
     caused bad surprises in replication setups.

   * *Replication*: Replication and *Note `mysqlbinlog': mysqlbinlog.
     now have better support for the case that the session character
     set and collation variables are changed within a given session. See
     *Note replication-features::.

   * The `Type' column name and values in the output from *Note `SHOW
     TABLES': show-tables. are now shown according to standard. The
     column name has changed from `Type' to `table_type'; permitted
     values are `BASE TABLE', `VIEW', and `ERROR'.  (Bug #4603)

   * Added `Last_query_cost' status variable that reports optimizer
     cost for last compiled query.

   * Changed that when the MySQL server has binary logging disabled
     (that is, no `--log-bin' option was used), then no transaction
     binary log cache is allocated for connections. This should save
     `binlog_cache_size' bytes of memory (32KB by default) for every
     connection.

   * Implemented a new `greedy search' optimizer that can significantly
     reduce the time spent on query optimization for some many-table
     joins. (You are affected if not only some particular *Note
     `SELECT': select. is slow, but even using *Note `EXPLAIN':
     explain. for it takes a noticeable amount of time.) Two new system
     variables, `optimizer_search_depth' and `optimizer_prune_level',
     can be used to fine-tune optimizer behavior.

   * *Note `OPTIMIZE TABLE': optimize-table. for `InnoDB' tables is now
     mapped to *Note `ALTER TABLE': alter-table. instead of *Note
     `ANALYZE TABLE': analyze-table. This rebuilds the table, which
     updates index statistics and frees space in the clustered index.

   * When a session having open temporary tables terminates, the
     statement automatically written to the binary log is now *Note
     `DROP TEMPORARY TABLE IF EXISTS': drop-table. instead of *Note
     `DROP TEMPORARY TABLE': drop-table, for more robustness.

   * Added support for read-only and updatable views based on a single
     table or other updatable views. View use requires that you upgrade
     your grant tables to add the view-related privileges. See *Note
     mysql-fix-privilege-tables::.

   * Added the `sql_updatable_view_key' system variable.

   * The MySQL server now returns an error if `SET sql_log_bin' is
     issued by a user without the `SUPER' privilege (in previous
     versions it just silently ignored the statement in this case).

   * When a database is dropped, all routines belonging to that
     database are also dropped.

   * Added the `--to-last-log' option to *Note `mysqlbinlog':
     mysqlbinlog, for use in conjunction with
     `--read-from-remote-server'.

   * `sync_frm' is now a settable global variable (not only a startup
     option).

   * Added `--innodb-safe-binlog' server option, which adds consistency
     guarantees between the content of `InnoDB' tables and the binary
     log. See *Note binary-log::.

   * Explicit `USE DB_NAME ' statements no longer are permitted in a
     stored procedure.

   * Added the `sync_binlog=N' global variable and startup option,
     which makes the MySQL server synchronize its binary log to disk
     (`fdatasync()') after every Nth write to the binary log.

   * Killing a *Note `CHECK TABLE': check-table. statement does not
     result in the table being marked as `corrupted' any more; the
     table remains as if *Note `CHECK TABLE': check-table. had not even
     started.  See *Note kill::.

   * Changed the slave SQL thread to print less useless error messages
     (no more message duplication; no more messages when an error is
     skipped because of `slave-skip-errors').

   * When executed from another database, an implicit `USE DB_NAME' is
     in effect.

   * When installing a MySQL server as a Windows service, the
     installation command can include a `--local-service' option
     following the service name to cause the server to run using the
     `LocalService' Windows account that has limited privileges. This
     is in addition to the `--defaults-file' option that also can be
     given following the service name.

   * Procedure names may be qualified, for example, `db.p()'

   * A stored procedure is no longer `global.' That is, it now belongs
     to a specific database:

        * When a database is dropped, all routines belonging to that
          database are also dropped.

        * Procedure names may be qualified, for example, `db.p()'

        * When executed from another database, an implicit `USE
          DB_NAME' is in effect.

        * Explicit `USE DB_NAME ' statements no longer are permitted in
          a stored procedure.

     See *Note stored-routines::.

*Bugs Fixed*

   * *Replication*: When a multiple-table *Note `DROP TABLE':
     drop-table.  failed to drop a table on the master server, the
     error was not written to the binary log.  (Bug #4553)

   * *Replication*: When the slave SQL thread was replicating a *Note
     `LOAD DATA INFILE': load-data. statement, it didn't show the
     statement in the output of *Note `SHOW PROCESSLIST':
     show-processlist.  (Bug #4326)

   * *Replication*: Complex expressions using `AND', `OR', or both
     could result in a crash if the query containing the expression
     query was ignored, either by a replication server due to
     `--replicate-*-table' rules, or by any MySQL server due to a
     syntax error.  (Bug #3969, Bug #4494)

   * *Replication*: The slave SQL thread refused to replicate *Note
     `INSERT ... SELECT': insert-select. if it examined more than 4
     billion rows.  (Bug #3871)

   * *Replication*: If `server-id' was not set using startup options
     but with *Note `SET GLOBAL': set-option, the replication slave
     still complained that it was not set.  (Bug #3829)

   * *Replication*: A MySQL slave server built using `--with-debug',
     and replicating itself, crashed.  (Bug #3568)

   * *Replication*: Multiple-table *Note `DELETE': delete. statements
     were always replicated by the slave if there were some
     `--replicate-*-ignore-table' options and no
     `--replicate-*-do-table' options.  (Bug #3461)

   * *Replication*: Memory could be corrupted by replicating a *Note
     `LOAD DATA INFILE': load-data. from a MySQL 3.23 master. Some less
     critical issues remain; see *Note replication-features::.  (Bug
     #3422)

   * *Replication*: In some replication error messages, a very long
     query caused the rest of the message to be invisible (truncated),
     by putting the query last in the message.  (Bug #3357)

   * *Replication*: Changed that when a thread handling *Note `INSERT
     DELAYED': insert-delayed. (also known as a `delayed_insert'
     thread) is killed, its statements are recorded with an error code
     of value zero (killing such a thread does not endanger
     replication, so we thus avoid a superfluous error on the slave).
     (Bug #3081)

   * *Replication*: Corrected the master's binary log position that
     `InnoDB' reports when it is doing a crash recovery on a slave
     server.  (Bug #3015)

   * *Replication*: `--replicate-wild-*-table' rules now apply to *Note
     `ALTER DATABASE': alter-database. when the table pattern is `%',
     as is the case for *Note `CREATE DATABASE': create-database. and
     *Note `DROP DATABASE': drop-database.  (Bug #3000)

   * *Replication*: Statements did not raise errors on the slave, if
     the slave was excluded given the `--replicate-*' options in use at
     the time. The effect of this problem was: when a statement was
     killed on the master, the slave stopped.  (Bug #2983)

   * *Replication*: Multiple-table *Note `DELETE': delete. statements
     were never replicated by the slave if there were any
     `--replicate-*-table' options.  (Bug #2527)

   * *Replication*: Replication: If a client connects to a slave server
     and issues an administrative statement for a table (for example,
     *Note `OPTIMIZE TABLE': optimize-table. or *Note `REPAIR TABLE':
     repair-table.), this could sometimes stop the slave SQL thread.
     This does not lead to any corruption, but you must use *Note
     `START SLAVE': start-slave. to get replication going again.  (Bug
     #1858)

   * If `CREATE TEMPORARY TABLE t SELECT' failed while loading the
     data, the temporary table was not dropped.  (Bug #4551)

   * *Note `mysql_fix_privilege_tables': mysql-fix-privilege-tables.
     did not handle the `--password=PASSWORD_VAL' option correctly.
     (Bug #4240, Bug #4543)

   * Made *Note `DROP DATABASE': drop-database. honor the value of
     `lower_case_table_names'.  (Bug #4066)

   * During the installation process of the server RPM on Linux, if
     *Note `mysqld': mysqld. was run as the `root' system user and with
     `--log-bin' pointing to a directory outside of `/var/lib/mysql',
     it created binary log files owned by `root' in this directory,
     which remained owned by `root' after the installation. Now *Note
     `mysqld': mysqld. is started as the `mysql' system user instead.
     (Bug #4038)

   * A potential memory overrun could occur in *Note
     `mysql_real_connect()': mysql-real-connect. (which required a
     compromised DNS server and certain operating systems).  (Bug #4017)

   * *Note `mysqlbinlog': mysqlbinlog. didn't escape the string content
     of user variables, and did not deal well when these variables were
     in non-ASCII character sets; this is now fixed by always printing
     the string content of user variables in hexadecimal.  The
     character set and collation of the string is now also printed.
     (Bug #3875)

   * *Note `mysqlbinlog': mysqlbinlog. failed to print a *Note `USE':
     use. statement under those rare circumstances where the binary log
     contained a *Note `LOAD DATA INFILE': load-data. statement.  (Bug
     #3415)

   * A rare error condition caused the slave SQL thread spuriously to
     print the message `Binlog has bad magic number' and stop when it
     was not necessary to do so.  (Bug #3401)

   * *Note `mysqlbinlog --read-from-remote-server': mysqlbinlog. now
     print the exact positions of events in lines beginning with `at #'
     in the log.  (Bug #3214)

   * *Note `mysqlbinlog --read-from-remote-server': mysqlbinlog. read
     all binary logs following the one that was requested. It now stops
     at the end of the requested file, the same as it does when reading
     a local binary log. There is an option `--to-last-log' to get the
     old behavior.  (Bug #3204)

   * Strange results with index (x, y) ... `WHERE x=VAL_1 AND y>=VAL_2
     ORDER BY PK;' (Bug #3155)

   * Adding `ORDER BY' to a query that uses a subquery can cause
     incorrect results.  (Bug #3118)

   * Changed that when a `DROP TEMPORARY TABLE' statement is
     automatically written to the binary log when a session ends, the
     statement is recorded with an error code of value zero (this
     ensures that killing a *Note `SELECT': select. on the master does
     not result in a superfluous error on the slave).  (Bug #3063)

   * When a `Rotate' event was found by the slave SQL thread in the
     middle of a transaction, the value of `Relay_Log_Pos' in *Note
     `SHOW SLAVE STATUS': show-slave-status. was incorrectly altered.
     (Bug #3017)

   * Running `LOAD DATA FROM MASTER' after *Note `RESET SLAVE':
     reset-slave. caused a segmentation fault.  (Bug #2922)

   * A deadlock ocurred when two *Note `START SLAVE': start-slave.
     statements were run at the same time.  (Bug #2921)

   * Changed the column `Seconds_Behind_Master' in *Note `SHOW SLAVE
     STATUS': show-slave-status. to never show a value of -1.  (Bug
     #2826)

   * Made clearer the error message that one gets when an update is
     refused because of the `--read-only' option.  (Bug #2757)

   * The MySQL server did not report any error if a statement
     (submitted through *Note `mysql_real_query()': mysql-real-query. or
     *Note `mysql_stmt_prepare()': mysql-stmt-prepare.) was terminated
     by garbage characters. This can happen if you pass a wrong
     `length' parameter to these functions.  The result was that the
     garbage characters were written into the binary log.  (Bug #2703)

   * `SLAVE START' (which is a deprecated syntax, *Note `START SLAVE':
     start-slave. should be used instead) could crash the slave.  (Bug
     #2516)

   * *Note `ALTER DATABASE': alter-database. caused the client to hang
     if the database did not exist.  (Bug #2333)

   * The `--local-load' option of *Note `mysqlbinlog': mysqlbinlog. now
     requires an argument.


File: manual.info,  Node: news-5-0-0,  Prev: news-5-0-1,  Up: news-5-0-x

D.1.97 Changes in MySQL 5.0.0 (22 December 2003 Alpha)
------------------------------------------------------

*Functionality Added or Changed*

   * *Important Change*: If you upgrade to MySQL 4.1.1 or higher, it is
     difficult to downgrade back to 4.0 or 4.1.0. That is because, for
     earlier versions, `InnoDB' is not aware of multiple tablespaces.

   * *Replication*: Easier replication upgrade (5.0.0 masters can read
     older binary logs and 5.0.0 slaves can read older relay logs). See
     *Note replication-compatibility::, for more details).  The format
     of the binary log and relay log is changed compared to that of
     MySQL 4.1 and older.

   * *Replication*: New binary log format that enables replication of
     these session variables: `sql_mode', `sql_auto_is_null',
     `foreign_key_checks' (which was replicated since 4.0.14, but here
     it is done more efficiently and takes less space in the binary
     logs), `unique_checks'. Other variables (like character sets,
     `sql_select_limit', ...) will be replicated in upcoming 5.0.x
     releases.

   * Added `TIMESTAMPADD()' and `TIMESTAMPDIFF()' functions.

   * The *Note `KILL': kill. statement now takes `CONNECTION' and
     `QUERY' modifiers. The first is the same as *Note `KILL': kill.
     with no modifier (it kills a given connection thread). The second
     kills only the statement currently being executed by the
     connection.

   * Added support for `SUM(DISTINCT)', `MIN(DISTINCT)', and
     `MAX(DISTINCT)'.

   * Basic support for stored procedures and functions (SQL:2003
     style). See *Note stored-routines::.

   * The output of the *Note `SHOW BINLOG EVENTS': show-binlog-events.
     statement has been modified. The `Orig_log_pos' column has been
     renamed to `End_log_pos' and now represents the offset of the last
     byte of the event, plus one.

   * Implemented Index Merge optimization for `OR' clauses. See *Note
     index-merge-optimization::.

   * For user-defined functions (UDFs), the `UDF_ARGS' structure now has
     `attributes' and `attribute_lengths' members that provide
     information about the argument names.  *Note udf-arguments::.

   * Added `WEEK' and `QUARTER' values as `INTERVAL' arguments for the
     `DATE_ADD()' and `DATE_SUB()' functions.

   * The precedence of the `XOR' operator now lies between `OR' and
     `AND'.  Previously, `XOR' had the same precedence as `OR'.

   * Added *Note `SELECT ... INTO LIST_OF_VARS': select-into, which can
     be of mixed (that is, global and local) types. See *Note
     select-into::.

   * *Note `LOAD DATA INFILE': load-data. causes an implicit commit.

     *Important*:

     The behavior of *Note `LOAD DATA INFILE': load-data. in this
     regard was changed again in MySQL 5.0.26. See *Note news-5-0-26::.


File: manual.info,  Node: mysql-cluster-change-history,  Next: connector-odbc-news,  Prev: news-5-0-x,  Up: news

D.2 Changes in MySQL Cluster
============================

* Menu:

* mysql-cluster-news-5-0-7::     Changes in MySQL Cluster-5.0.7 (10 June 2005)
* mysql-cluster-news-5-0-6::     Changes in MySQL Cluster-5.0.6 (26 May 2005)
* mysql-cluster-news-5-0-5::     Changes in MySQL Cluster-5.0.5 (Not released)
* mysql-cluster-news-5-0-4::     Changes in MySQL Cluster-5.0.4 (16 April 2005)
* mysql-cluster-news-5-0-3::     Changes in MySQL Cluster-5.0.3 (23 March 2005: Beta)
* mysql-cluster-news-5-0-1::     Changes in MySQL Cluster-5.0.1 (27 July 2004)
* mysql-cluster-news-4-1-13::    Changes in MySQL Cluster-4.1.13 (15 July 2005)
* mysql-cluster-news-4-1-12::    Changes in MySQL Cluster-4.1.12 (13 May 2005)
* mysql-cluster-news-4-1-11::    Changes in MySQL Cluster-4.1.11 (01 April 2005)
* mysql-cluster-news-4-1-10::    Changes in MySQL Cluster-4.1.10 (12 February 2005)
* mysql-cluster-news-4-1-9::     Changes in MySQL Cluster-4.1.9 (13 January 2005)
* mysql-cluster-news-4-1-8::     Changes in MySQL Cluster-4.1.8 (14 December 2004)
* mysql-cluster-news-4-1-7::     Changes in MySQL Cluster-4.1.7 (23 October 2004)
* mysql-cluster-news-4-1-6::     Changes in MySQL Cluster-4.1.6 (10 October 2004)
* mysql-cluster-news-4-1-5::     Changes in MySQL Cluster-4.1.5 (16 September 2004)
* mysql-cluster-news-4-1-4::     Changes in MySQL Cluster-4.1.4 (31 August 2004)
* mysql-cluster-news-4-1-3::     Changes in MySQL Cluster-4.1.3 (28 June 2004)

*Beginning with MySQL 4.1.13 and MySQL 5.0.7, all Cluster changes for
MySQL Server releases through MySQL 5.1.24 are included in the MySQL
Change History, and this manual section is no longer separately
maintained.*

Following MySQL 5.1.24, `NDB' support in MySQL 5.1 was dropped, and
MySQL Cluster development moved to the MySQL NDB 6.X and NDB 7.X
release series, based on MySQL 5.1, but maintained and released
separately. For changes in these releases, see Changes in MySQL Cluster
NDB 6.X and 7.X
(http://dev.mysql.com/doc/refman/5.1/en/mysql-cluster-news.html#mysql-cluster-news).


File: manual.info,  Node: mysql-cluster-news-5-0-7,  Next: mysql-cluster-news-5-0-6,  Prev: mysql-cluster-change-history,  Up: mysql-cluster-change-history

D.2.1 Changes in MySQL Cluster-5.0.7 (10 June 2005)
---------------------------------------------------

*Note*:

Starting with version 5.0.8, changes for MySQL Cluster can be found in
the combined MySQL Change History.

Functionality added or changed:

Bugs fixed:

   * (Bug #11019) mgmapi start backup in some cases returns wrong
     backupid

   * (Bug #10190) Backup from cluster wih NoOfReplica=1 is corrupt

   * (Bug #9246) Condition pushdown and left join, wrong result

   * (Bug #10956) More than 7 node restarts with `--initial' caused
     cluster to fail.

   * (Bug #9945) *Note `ALTER TABLE': alter-table. caused server crash.
     (Linux/390)

   * (Bug #9826) (Bug #10948) Schema change (*Note `DROP TABLE':
     drop-table, *Note `ALTER TABLE': alter-table.) crashed HPUX and
     PPC32.

   * (Bug #10711) (Bug #9363) (Bug #8918) (Bug #10058) (Bug #9025)
     Cluster would time out and crash after first query; setting
     DataMemory to more than 2GB prevented cluster from starting;
     calling `ndb_select_count()' crashed the cluster. (64-bit Unix
     OSes)


File: manual.info,  Node: mysql-cluster-news-5-0-6,  Next: mysql-cluster-news-5-0-5,  Prev: mysql-cluster-news-5-0-7,  Up: mysql-cluster-change-history

D.2.2 Changes in MySQL Cluster-5.0.6 (26 May 2005)
--------------------------------------------------

Functionality added or changed:

   * Limit on number of metadata objects (number of tables, indexes and
     BLOBs) now increased to 20,320

Bugs fixed:

   * The server would hang on successive calls to an *Note `INSERT ...
     ON DUPLICATE KEY UPDATE': insert-on-duplicate. query. (Bug #9725)

   * (Bug #10193) Invalid DataDir in config causes ndbd segmentation
     fault

   * (Bug #10813) Build with SCI Transporter fails

   * (Bug #10831) ndb mgmd LogDestination maxfiles does not rotate logs
     properly


File: manual.info,  Node: mysql-cluster-news-5-0-5,  Next: mysql-cluster-news-5-0-4,  Prev: mysql-cluster-news-5-0-6,  Up: mysql-cluster-change-history

D.2.3 Changes in MySQL Cluster-5.0.5 (Not released)
---------------------------------------------------

Functionality added or changed:

   * Decreased IndexMemory Usage

   * Parallel key lookup (read-multi-range) for queries like `SELECT *
     FROM t1 WHERE primary_key IN (1,2,3,4,5,6,7,8,9,10);'

Bugs fixed:

     Patches merged from versions 4.1.11 and 4.1.12

   * (Bug #8315) NdbScanFilter cmp method only works for strings of
     exact word boundary length

   * (Bug #8103) Configuration handling error

   * (Bug #8035) mysqld signal 10 when ndbd is shutdown

   * (Bug #7631) NDB$EVENT contains unreadable event and table names

   * (Bug #7628) Filtered event types are ignored

   * (Bug #7627) Drop Event operation fails

   * (Bug #7424) create index on datetime fails


File: manual.info,  Node: mysql-cluster-news-5-0-4,  Next: mysql-cluster-news-5-0-3,  Prev: mysql-cluster-news-5-0-5,  Up: mysql-cluster-change-history

D.2.4 Changes in MySQL Cluster-5.0.4 (16 April 2005)
----------------------------------------------------

Functionality added or changed:

   * Condition pushdown to storage engine now works for update and
     delete as well

Bugs fixed:

   * (Bug #9675) Auto-increment not working with INSERT..SELECT and NDB
     storage

   * (Bug #9517) Condition pushdown to storage engine does not work for
     update/delete

   * (Bug #9282) API Node Crashes/Reloads on 'DELETE FROM'

   * (Bug #9280) Memory leak in cluster when dependent sub-queries are
     used

   * (Bug #8585) ndb_cache2 fails on aix52


File: manual.info,  Node: mysql-cluster-news-5-0-3,  Next: mysql-cluster-news-5-0-1,  Prev: mysql-cluster-news-5-0-4,  Up: mysql-cluster-change-history

D.2.5 Changes in MySQL Cluster-5.0.3 (23 March 2005: Beta)
----------------------------------------------------------

Functionality added or changed:

   * Condition pushdown to storage engine

   * Query cache enabled for cluster

Bugs fixed:

   * Patches merged from version 4.1.10


File: manual.info,  Node: mysql-cluster-news-5-0-1,  Next: mysql-cluster-news-4-1-13,  Prev: mysql-cluster-news-5-0-3,  Up: mysql-cluster-change-history

D.2.6 Changes in MySQL Cluster-5.0.1 (27 July 2004)
---------------------------------------------------

Functionality added or changed:

   * This was the first MySQL Cluster release in the 5.0 series. As
     nearly all attention was still focused on getting 4.1 stable, it
     is not recommended to use MySQL 5.0.1 for MySQL Cluster.

Bugs fixed:

   * N/A


File: manual.info,  Node: mysql-cluster-news-4-1-13,  Next: mysql-cluster-news-4-1-12,  Prev: mysql-cluster-news-5-0-1,  Up: mysql-cluster-change-history

D.2.7 Changes in MySQL Cluster-4.1.13 (15 July 2005)
----------------------------------------------------

Functionality added or changed:

Bugs fixed:

   * (Bug #11132) Connections between data nodes and management nodes
     were not being closed following shutdown of `ndb_mgmd'.

   * (Bug #11050) `ndb_mgm> show' printed incorrectly after master data
     node failure.

   * (Bug #10956) More than 7 node restarts with `--initial' caused
     cluster to fail.

   * (Bug #9826) (Bug #10948) Schema change (*Note `DROP TABLE':
     drop-table, *Note `ALTER TABLE': alter-table.) crashed HPUX and
     PPC32.

   * (Bug #9025) Data nodes failed to restart on 64-bit Solaris.

   * (Bug #11166) Insert records were incorrectly applied by
     `ndb_restore', thus making restoration from backup inconsistent if
     the binlog contained inserts.

   * (Bug #8918) (Bug #9363) (Bug #10711) (Bug #10058) (Bug #9025)
     Cluster would time out and crash after first query; setting
     DataMemory to more than 2GB prevented cluster from starting;
     calling `ndb_select_count()' crashed the cluster. (64-bit Unix
     OSes)

   * (Bug #10190) When making a backup of a cluster where
     `NumberOfReplicas' was equal to 1, the backup's metadata was
     corrupted. (Linux)

   * (Bug #9945) *Note `ALTER TABLE': alter-table. caused server crash.
     (Linux/390)

   * (Bug #11133) A delete operation performed as part of a transaction
     caused an erroneous result.

   * (Bug #10294) Not allowing sufficient parallelism in cluster
     configuration (for example, `NoOfTransactions' too small) caused
     `ndb_restore' to fail without generating any error messages.

   * (Bug #11290) Setting TransactionInactiveTimeout= 0 did not result
     in an infinite timeout.


File: manual.info,  Node: mysql-cluster-news-4-1-12,  Next: mysql-cluster-news-4-1-11,  Prev: mysql-cluster-news-4-1-13,  Up: mysql-cluster-change-history

D.2.8 Changes in MySQL Cluster-4.1.12 (13 May 2005)
---------------------------------------------------

Functionality added or changed:

Bugs fixed:

   * (Bug #10471) Backup can become inconsistent with certain
     combinations of multiple-row updates

   * (Bug #10287) ndb_select_all "delimiter" option non functional

   * (Bug #10142) Unhandled resource shortage in UNIQUE index code

   * (Bug #10029) crash in ordered index scan after db full

   * (Bug #10001) 2 NDB nodes get signal 6 (abort) in DBTC

   * (Bug #9969) 4012 - has misleading error message

   * (Bug #9960) START BACKUP reports failure albeit succeeding

   * (Bug #9924) ABORT BACKUP 1 crashes 4 node cluster

   * (Bug #9892) Index activation file during node recovery

   * (Bug #9891) Crash in DBACC (line 7004) during commit

   * (Bug #9865) SELECT does not function properly

   * (Bug #9839) Column with AUTOINC contains -1 Value on node stop

   * (Bug #9757) Uncompleted node failure after gracefully stopping node

   * (Bug #9749) Transactions causes deadlock in ACC

   * (Bug #9724) Node fails to start: Message: File has already been
     opened

   * (Bug #9691) UPDATE fails on attempt to update primary key

   * (Bug #9675) Auto-increment not working with INSERT..SELECT and NDB
     storage

   * (Bug #9318) drop database does not drop ndb tables

   * (Bug #9280) Memory leak in cluster when dependent sub-queries are
     used

   * (Bug #8928) create table with keys will shutdown the cluster

   * Creating a table did not work for a cluster with 6 nodes. (Bug
     #8928) Databases with 1, 2, 4, 8, ...  (2^N nodes) did not have
     the problem. After a rolling upgrade, restart each node manually
     by restarting it with the `--initial' option. Otherwise, use dump
     and restore after an upgrade.


File: manual.info,  Node: mysql-cluster-news-4-1-11,  Next: mysql-cluster-news-4-1-10,  Prev: mysql-cluster-news-4-1-12,  Up: mysql-cluster-change-history

D.2.9 Changes in MySQL Cluster-4.1.11 (01 April 2005)
-----------------------------------------------------

Functionality added or changed:

Bugs fixed:

   * (Bug #9916) DbaccMain.cpp / DBACC (Line: 4876) / Pointer too large

   * (Bug #9435) TIMESTAMP columns do not update

   * (Bug #9052) Uninitialized data during unique index build,
     potential cluster crash

   * (Bug #8876) Timeout when committing aborted transaction after node
     failure

   * (Bug #8786) ndb_autodiscover, drop index can fail, wait 2 minutes
     timeout

   * (Bug #8853) Transaction aborted after long time during node
     failure (4012)

   * (Bug #8753) Invalid schema object version after dropping index
     (crash fixed, currently retry required)

   * (Bug #8645) Assertion failure with multiple management servers

   * (Bug #8557) ndbd does not get same nodeid on restart

   * (Bug #8556) corrupt ndb_mgm show printout for certain
     configurations

   * (Bug #8167) cluster shared memory and mysqld signal usage clash


File: manual.info,  Node: mysql-cluster-news-4-1-10,  Next: mysql-cluster-news-4-1-9,  Prev: mysql-cluster-news-4-1-11,  Up: mysql-cluster-change-history

D.2.10 Changes in MySQL Cluster-4.1.10 (12 February 2005)
---------------------------------------------------------

Bugs fixed:

   * (Bug #8284) Out of fragment memory in DBACC

   * (Bug #8262) Node crash due to bug in DBLQH

   * (Bug #8208) node restart fails on Aix 5.2

   * (Bug #8167) cluster shared memory and mysqld signal usage clash

   * (Bug #8101) unique index and error 4209 while selecting

   * (Bug #8070) (Bug #7937) (Bug #6716) various ndb_restore core dumps
     on HP-UX

   * (Bug #8010) 4006 forces MySQL Node Restart

   * (Bug #7928) out of connection objects

   * (Bug #7898) mysqld crash with ndb (solaris)

   * (Bug #7864) Not possible to have more than 4.5G data memory


File: manual.info,  Node: mysql-cluster-news-4-1-9,  Next: mysql-cluster-news-4-1-8,  Prev: mysql-cluster-news-4-1-10,  Up: mysql-cluster-change-history

D.2.11 Changes in MySQL Cluster-4.1.9 (13 January 2005)
-------------------------------------------------------

Functionality added or changed:

   * New implementation of shared memory transporter.

   * Cluster automatically configures shared memory transporter if
     possible.

   * Cluster prioritizes usage of transporters with shared memory and
     localhost TCP

   * Added switches to control the above functions, `ndb-shm' and
     `ndb-optimized-node-selection'.

Bugs fixed:

   * (Bug #7805) config.ini parsing error

   * (Bug #7798) Running range scan after alter table in different
     thread causes node failure

   * (Bug #7761) Alter table does not autocommit

   * (Bug #7725) Indexed DATETIME Columns Return Random Results

   * (Bug #7660) START BACKUP does not increment BACKUP-ID (Big Endian
     machines)

   * (Bug #7593) Cannot Create A Large NDB Data Warehouse

   * (Bug #7480) Mysqld crash in ha_ndbcluster using Query Browser

   * (Bug #7470) shared memory transporter does not connect

   * (Bug #7396) Primary Key not working in NDB Mysql Clustered table
     (solaris)

   * (Bug #7379) ndb restore fails to handle blobs and multiple
     databases

   * (Bug #7346) ndb_restore enters infinite loop

   * (Bug #7340) Problem for inserting data into the Text field on utf8

   * (Bug #7124) ndb_mgmd is aborted on startup when using SHM
     connection


File: manual.info,  Node: mysql-cluster-news-4-1-8,  Next: mysql-cluster-news-4-1-7,  Prev: mysql-cluster-news-4-1-9,  Up: mysql-cluster-change-history

D.2.12 Changes in MySQL Cluster-4.1.8 (14 December 2004)
--------------------------------------------------------

Functionality added or changed:

   * Default port for *Note `ndb_mgmd':
     mysql-cluster-programs-ndb-mgmd. was changed to 1186 (from 2200)
     as this port number was officially assigned to MySQL Cluster by
     IANA.

   * New command in *Note `ndb_mgm': mysql-cluster-programs-ndb-mgm,
     PURGE STALE SESSIONS, as a workaround for cases where nodes fail to
     allocate a node id even if it is free to use.

   * New command in *Note `ndb_mgm': mysql-cluster-programs-ndb-mgm,
     CONNECT.

   * The ndb executables have been changed to make use of the regular
     MySQL command-line option parsing features. See *Note
     mysql-cluster-program-options-common::, for notes on changes.

   * As bonus of the above you can now specify all command line options
     in `my.cnf' using the executable names as sections, that is,
     `[ndbd]', `[ndb_mgmd]', `[ndb_mgm]', `[ndb_restore]', and so forth.

                [ndbd]
                ndb-connectstring=myhost.domain.com:1234
                [ndb_mgm]
                ndb-connectstring=myhost.domain.com:1234

   * Added use of section `[mysql_cluster]' in `my.cnf'. All cluster
     executables, including mysqld, parse this section. For example,
     this is a convenient place to put `ndb-connectstring' so that it
     need be specified only once.

   * Added cluster log info events on allocation and deallocation of
     nodeid's.

   * Added cluster log info events on connection refuse as a result of
     version mismatch.

   * Extended connectstring syntax to allow for leaving the port number
     out. For example,
     `ndb-connectstring|connect-string=myhost1,myhost2,myhost3' is a
     valid connectstring and connect occurs on default port 1186.

   * Clear text ndb error messages provided also for error codes that
     are mapped to corresponding mysql error codes, by executing *Note
     `SHOW WARNINGS': show-warnings. after an error has occurred which
     relates to the ndb storage engine.

   * Significant performance improvements done for read performance,
     especially for blobs.

   * Added some variables for performance tuning, `ndb_force_send' and
     `ndb_use_exact_count'. Do `show variables like 'ndb%';' in mysql
     client for listing. Use `set' command to alter variables.

   * Added variables to set some options, `ndb_use_transactions' and
     `ndb_autoincrement_prefetch_sz'.

Bugs fixed:

   * (Bug #7303) ndb_mgm: Trying to set CLUSTERLOG for a specific node
     id core dumps

   * (Bug #7193) start backup gives false error printout

   * (Bug #7153) Cluster nodes do not report error on endianness
     mismatch

   * (Bug #7152) ndb_mgmd segmentation fault on incorrect HostName in
     configuration

   * (Bug #7104) clusterlog filtering and level setting broken

   * (Bug #6995) ndb_recover on varchar fields results in changing case
     of data

   * (Bug #6919) all status only shows 2 nodes on a 8-node cluster

   * (Bug #6871) DBD execute failed: Got error 897 'Unknown error code'
     from ndbcluster

   * (Bug #6794) Wrong outcome of update operation of ndb table

   * (Bug #6791) Segmentation fault when config.ini is not correctly set

   * (Bug #6775) failure in acc when running many mysql clients

   * (Bug #6696) ndb_mgm command-line options inconsistent with behavior

   * (Bug #6684) ndb_restore doesn't give error messages if improper
     command given

   * (Bug #6677) ndb_mgm can crash on "ALL CLUSTERLOG"

   * (Bug #6538) Error code returned when select max() on empty table
     with index

   * (Bug #6451) failing create table givers "ghost" tables which are
     impossible to remove

   * (Bug #6435) strange behavior of left join

   * (Bug #6426) update with long pk fails

   * (Bug #6398) update of primary key fails

   * (Bug #6354) mysql does not complain about -ndbcluster option when
     NDB is not compiled in

   * (Bug #6331) INSERT IGNORE .. SELECT breaks subsequent inserts

   * (Bug #6288) cluster nodes crash on data import

   * (Bug #6031) To drop database you have to execute DROP DATABASE
     command twice

   * (Bug #6020) LOCK TABLE + delete returns error 208

   * (Bug #6018) REPLACE does not work for BLOBs + NDB

   * (Bug #6016) Strange crash with blobs + different DATABASES

   * (Bug #5973) ndb table belonging to different database shows up in
     show tables

   * (Bug #5872) ALTER TABLE with blob from ndb table to myisam fails

   * (Bug #5844) Failing mysql-test-run leaves stray NDB processes
     behind

   * (Bug #5824) HELP text messed up in ndb_mgm

   * (Bug #5786) Duplicate key error after restore

   * (Bug #5785) lock timeout during concurrent update

   * (Bug #5782) Unknown error when using LIMIT with ndb table

   * (Bug #5756) RESTART node from ndb_mgm fails

   * A few more not reported bugs fixed


File: manual.info,  Node: mysql-cluster-news-4-1-7,  Next: mysql-cluster-news-4-1-6,  Prev: mysql-cluster-news-4-1-8,  Up: mysql-cluster-change-history

D.2.13 Changes in MySQL Cluster-4.1.7 (23 October 2004)
-------------------------------------------------------

Functionality added or changed:

   * Optimization 1: Improved performance on index scans. Measured 30%
     performance increase on query which do large amounts of index
     scans.

   * Optimization 2: Improved performance on primary key lookups.
     Around double performance for autocommitted primary key lookups.

   * Optimization 3: Improved performance when using blobs by avoiding
     usage of exclusive locks for blobs.

Bugs fixed:

   * A few bugs fixed.


File: manual.info,  Node: mysql-cluster-news-4-1-6,  Next: mysql-cluster-news-4-1-5,  Prev: mysql-cluster-news-4-1-7,  Up: mysql-cluster-change-history

D.2.14 Changes in MySQL Cluster-4.1.6 (10 October 2004)
-------------------------------------------------------

Functionality added or changed:

   * Limited character set support for storage engine NDBCLUSTER:

     Character Set               Collation
     big5                        big5_chinese_ci
                                 big5_bin
     binary                      binary
     euckr                       euckr_korean_ci
                                 euckr_bin
     gb2312                      gb2312_chinese_ci
                                 gb2312_bin
     gbk                         gbk_chinese_ci
                                 gbk_bin
     latin1                      latin1_swedish_ci
                                 latin1_bin
     sjis                        sjis_japanese_ci
                                 sjis_bin
     tis620                      tis620_bin
     ucs2                        ucs2_general_ci
                                 ucs2_bin
     ujis                        ujis_japanese_ci
                                 ujis_bin
     utf8                        utf8_general_ci
                                 utf8_bin

   * The SCI Transporter has been brought up-to-date with all changes
     and now works and has been documented as well.

   * Optimizations when several clients to a MySQL Server access ndb
     tables.

   * Added more checks and warnings for erroneous and inappropriate
     cluster configurations.

   * *Note `SHOW TABLES': show-tables. now directly shows ndb tables
     created on a different MySQL server, that is, without a prior
     table access.

   * Enhanced support for starting MySQL Server independently of ndbd
     and ndb_mgmd.

   * Clear text ndb error messages provided by executing *Note `SHOW
     WARNINGS': show-warnings. after an error has occurred which
     relates to the ndb storage engine.

Bugs fixed:

   * Quite a few bugs fixed.


File: manual.info,  Node: mysql-cluster-news-4-1-5,  Next: mysql-cluster-news-4-1-4,  Prev: mysql-cluster-news-4-1-6,  Up: mysql-cluster-change-history

D.2.15 Changes in MySQL Cluster-4.1.5 (16 September 2004)
---------------------------------------------------------

Functionality added or changed:

   * Many queries in MySQL Cluster are executed as range scans or full
     table scans. All queries that do not use a unique hash index or
     the primary hash index use this access method. In a distributed
     system it is crucial that batching is properly performed.

     In previous versions, the batch size was fixed to 16 per data
     node. In this version it is configurable per MySQL Server. So for
     queries using lots of large scans it is appropriate to set this
     parameter rather large and for queries using many small scans only
     fetching a small amount of records it is appropriate to set it low.

     The performance of queries can easily change as much as 40% based
     on how this variable is set.

     In future versions more logic will be implemented for assessing
     the batch size on a per-query basis. Thus, the semantics of the
     new configuration variable `ScanBatchSize' are likely to change.

   * The fixed size overhead of the ndbd process has been greatly
     decreased. This is also true for the overhead per operation record
     as well as overhead per table and index.

     A number of new configuration variables have been introduced to
     enable configuration of system buffers. Configuration variables
     for specifying the numbers of tables, unique hash indexes, and
     ordered indexes have also been introduced.

     New configuration variables: `MaxNoOfOrderedIndexes',
     `MaxNoOfUniqueHashIndexes'

     Configuration variables no longer used: `MaxNoOfIndexes' (split
     into the two above).

   * In previous versions *Note `ALTER TABLE': alter-table, *Note
     `TRUNCATE TABLE': truncate-table, and *Note `LOAD DATA': load-data.
     were performed as one big transaction. In this version, all of
     these statements are automatically separated into several distinct
     transactions.

     This removes the limitation that one could not change very large
     tables due to the `MaxNoOfConcurrentOperations' parameter.

   * MySQL CLuster's online backup feature now backs up indexes so that
     both data and indexes are restored.

   * In previous versions it was not possible to use `NULL' in indexes.
     This is now possible for all supported index types.

   * Much work has been put onto making `AUTO_INCREMENT' features work
     as for other table handlers. Autoincrements as a partial key is
     still only supported by `MyISAM'.

   * In earlier versions, *Note `mysqld': mysqld. would crash if the
     cluster wasn't started with the `--ndbcluster' option. Now *Note
     `mysqld': mysqld. handles cluster crashes and starts without
     crashing.

   * The `-i' option for initial startup of *Note `ndbd':
     mysql-cluster-programs-ndbd. has been removed. Initial startup
     still can be specified by using the `--initial' option. The reason
     for this is to ensure that it is clear what takes place when using
     `--initial': this option completely removes all data from the disk
     and should only be used at initial start, in certain software
     upgrade cases, and in some cases as a workaround when nodes cannot
     be restarted successfully.

   * The management client (*Note `ndb_mgm':
     mysql-cluster-programs-ndb-mgm.) now has additional commands and
     more information is printed for some commands such as `show'.

   * In previous versions, the files were called `ndb_0..' when it
     wasn't possible to allocate a node ID when starting the node. To
     ensure that files are not so easily overwritten, these files are
     now named `ndb_pid..', where pid is the process ID assigned by the
     OS.

   * The default parameters have changed for *Note `ndb_mgmd':
     mysql-cluster-programs-ndb-mgmd. and *Note `ndbd':
     mysql-cluster-programs-ndbd. In particular, they are now started
     as daemons by default. The `-n' option has been removed since it
     could cause confusion as to its meaning (nostart or nodaemon).

   * In the configuration file, you can now use `[NDBD]' as an alias for
     `[DB]', `[MYSQLD]' as an alias for `[API]', and `[NDB_MGMD]' as an
     alias for `[MGM]'.

     *Note*:

     In fact, `[NDBD]', `[MYSQLD]', and `[NDB_MGMD]' are now the
     preferred designations, although the older ones will continue to be
     supported for some time to come to maintain backward compatibility.

   * Many more checks for consistency in configuration have been
     introduced to to provide quicker feedback on configuration errors.

   * In the connect string, it is now possible to use both ``;'' and
     ``,'' as the separator between entries. Thus,
     "nodeid=2,host=localhost:2200" is equivalent to
     "nodeid=2;host=localhost:2200".

     In the configuration file, it is also possible to use ``:'' or
     ``='' for assignment values. For example, `MaxNoOfOrderedIndexes :
     128' and `MaxNoOfOrderedIndexes = 128' are equivalent expressions.

   * The configuration variable names are now case insensitive, so
     `MaxNoOfOrderedIndexes: 128' is equivalent to
     `MAXNOOFORDEREDINDEXES = 128'.

   * It is possible now to set the backup directory separately from the
     `FileSystemPath' by using the `BackupDir' configuration variable.

     Log files and trace files can now be placed in any directory by
     setting the `DataDir' configuration variable.

     `FileSystemPath' is no longer mandatory and defaults to `DataDir'.

   * Queries involving tables from different databases are now
     supported.

   * It is now possible to update the primary key.

   * The performance of ordered indexes has been greatly improved,
     particularly the maintenance of indexes on updates, inserts and
     deletes.

Bugs fixed:

   * Quite a few bugs fixed.


File: manual.info,  Node: mysql-cluster-news-4-1-4,  Next: mysql-cluster-news-4-1-3,  Prev: mysql-cluster-news-4-1-5,  Up: mysql-cluster-change-history

D.2.16 Changes in MySQL Cluster-4.1.4 (31 August 2004)
------------------------------------------------------

Functionality added or changed:

   * The names of the log files and trace files created by the *Note
     `ndbd': mysql-cluster-programs-ndbd. and *Note `ndb_mgmd':
     mysql-cluster-programs-ndb-mgmd.  processes have changed.

   * Support for the many *Note `BLOB': blob. data types was introduced
     in this version.

Bugs fixed:

   * Quite a few bugs were fixed in the 4.1.4 release.


File: manual.info,  Node: mysql-cluster-news-4-1-3,  Prev: mysql-cluster-news-4-1-4,  Up: mysql-cluster-change-history

D.2.17 Changes in MySQL Cluster-4.1.3 (28 June 2004)
----------------------------------------------------

Functionality added or changed:

   * This was the first MySQL Cluster release so all functionality was
     new.

Bugs fixed:

   * Various bugs fixed in the development process leading up to 4.1.3.


File: manual.info,  Node: connector-odbc-news,  Next: connector-net-news,  Prev: mysql-cluster-change-history,  Up: news

D.3 MySQL Connector/ODBC (MyODBC) Change History
================================================

* Menu:

* connector-odbc-news-5-1-x::    Changes in MySQL Connector/ODBC Version 5.1.x
* connector-odbc-news-5-0-x::    Changes in MySQL Connector/ODBC Version 5.0.x
* connector-odbc-news-3-51-x::   Changes in MySQL Connector/ODBC Version 3.51.x


File: manual.info,  Node: connector-odbc-news-5-1-x,  Next: connector-odbc-news-5-0-x,  Prev: connector-odbc-news,  Up: connector-odbc-news

D.3.1 Changes in MySQL Connector/ODBC Version 5.1.x
---------------------------------------------------

* Menu:

* connector-odbc-news-5-1-9::    Changes in MySQL Connector/ODBC 5.1.9 (06 October 2011)
* connector-odbc-news-5-1-8::    Changes in MySQL Connector/ODBC 5.1.8 (07 November 2010)
* connector-odbc-news-5-1-7::    Changes in MySQL Connector/ODBC 5.1.7 (24 August 2010)
* connector-odbc-news-5-1-6::    Changes in MySQL Connector/ODBC 5.1.6 (09 November 2009)
* connector-odbc-news-5-1-5::    Changes in MySQL Connector/ODBC 5.1.5 (18 August 2008)
* connector-odbc-news-5-1-4::    Changes in MySQL Connector/ODBC 5.1.4 (15 April 2008)
* connector-odbc-news-5-1-3::    Changes in MySQL Connector/ODBC 5.1.3 (26 March 2008)
* connector-odbc-news-5-1-2::    Changes in MySQL Connector/ODBC 5.1.2 (13 February 2008)
* connector-odbc-news-5-1-1::    Changes in MySQL Connector/ODBC 5.1.1 (13 December 2007)
* connector-odbc-news-5-1-0::    Changes in MySQL Connector/ODBC 5.1.0 (10 September 2007)


File: manual.info,  Node: connector-odbc-news-5-1-9,  Next: connector-odbc-news-5-1-8,  Prev: connector-odbc-news-5-1-x,  Up: connector-odbc-news-5-1-x

D.3.1.1 Changes in MySQL Connector/ODBC 5.1.9 (06 October 2011)
...............................................................

Only the source code and Windows binaries are available with this
release.

The 64-bit MSI installer no longer contains 32-bit and 64-bit builds of
the driver, like it did in previous versions. It now only includes
64-bit support.

*Pluggable Authentication Notes*
   * The binaries for this distribution of Connector/ODBC can now
     connect to MySQL server accounts that use the PAM or Windows
     Native Authentication Plugins for authentication. See The PAM
     Authentication Plugin
     (http://dev.mysql.com/doc/refman/5.5/en/pam-authentication-plugin.html),
     and The Windows Native Authentication Plugin
     (http://dev.mysql.com/doc/refman/5.5/en/windows-authentication-plugin.html).
     These capabilities result from linking the Connector/ODBC binaries
     against the MySQL 5.5.16 `libmysql' rather than the MySQL 5.1
     `libmysql' used previously. The newer `libmysql' includes the
     client-side support needed for the server-side PAM and Windows
     authentication plugins.

*Bugs Fixed*

   * Some catalog functions (such as `SQLColumns()', `SQLStatistics()',
     and `SQLPrimaryKeys()') would only return one row, when called
     after pre-execution failed.  (Bug #12824839)

   * The CLI installer script `mysqlodbc-installer' was missing
     documentation about how to configure the optional data source
     parameters.  (Bug #12810058)

   * The `Install.bat' script contained leftover `3.51' information,
     and did not properly install the `5.1' Connector/ODBC connector.
     (Bug #12781039)

   * An off-by-one error, where `sqlwcharchr' might read one `SQLWCHAR'
     after the end of a string.  (Bug #61586)

   * `SQLExecute' would return `SQL_SUCCESS_WITH_INFO' instead of
     `SQL_ERROR', when column parameter binding was enabled.  (Bug
     #59772)

   * The Connector/ODBC driver did not call *Note `mysql_thread_end()':
     mysql-thread-end. when a thread ended, which caused error messages
     like: `Error in my_thread_global_end(): 1 threads didn't exit'.
     (Bug #57727)

   * When using MySQL Connector/ODBC to fetch data, if a
     `net_write_timeout' condition occurred, the operation returned the
     standard "end of data" status, rather than an error.  (Bug #39878)

   * MS Access fields with `VARCHAR NOT NULL' columns could not be
     altered.  (Bug #31067)


File: manual.info,  Node: connector-odbc-news-5-1-8,  Next: connector-odbc-news-5-1-7,  Prev: connector-odbc-news-5-1-9,  Up: connector-odbc-news-5-1-x

D.3.1.2 Changes in MySQL Connector/ODBC 5.1.8 (07 November 2010)
................................................................

*Functionality Added or Changed*

   * Documentation in `.CHM' and `.HLP' format has been removed from the
     distribution.  (Bug #56232)

*Bugs Fixed*

   * For some procedure and parameter combinations
     `SQLProcedureColumns()' did not work correctly.  For example, it
     could not return records for an existing procedure with correct
     parameters supplied.

     Further, it returned incorrect data for column 7, `TYPE_NAME'. For
     example, it returned `VARCHAR(20)' instead of `VARCHAR'.  (Bug
     #57182)

   * The MySQL Connector/ODBC MSI installer did not set the
     `InstallLocation' value in the Microsoft Windows registry.  (Bug
     #56978)

   * In bulk upload mode, `SQLExecute' would return `SQL_SUCCESS', even
     when the uploaded data contained errors, such as primary key
     duplication, and foreign key violation.  (Bug #56804)

   * `SQLDescribeCol' and `SQLColAttribute' could not be called before
     `SQLExecute', if the query was parameterized and not all
     parameters were bound.

     Note, MSDN states that `For performance reasons, an application
     should not call `SQLColAttribute/SQLDescribeCol' before executing
     a statement.' However, it should still be possible to do so if
     performance reasons are not paramount.  (Bug #56717)

   * When `SQLNumResultCols()' was called between `SQLPrepare()' and
     `SQLExecute()' the driver ran `SET @@sql_select_limit=1', which
     limited the resultset to just one row.  (Bug #56677)

   * After installing MySQL Connector/ODBC, the system DSN created
     could not be configured or deleted. An error dialog was displayed,
     showing the error message `Invalid attribute string'.

     In this case the problem was due to the fact that the driver could
     not parse the NULL-separated connection string.  (Bug #56233)

   * When used after a call to `SQLTables()', `SQLRowCount()' did not
     return the correct value.  (Bug #55870)

   * When attempting to install the latest Connector/ODBC 5.1.6 on
     Windows using the MSI, with an existing 5.1.x version already
     installed, the following error was generated:

          Another version of this product is already installed.  Installation of this version
          cannot continue.  To configure or remove the existing version of this product, use
          Add/Remove Programs on the Control Panel.

     Also, the version number displayed in the ODBC Data Source
     Administrator/Drivers tab did not get updated when removing or
     installing a new version of 5.1.x.  (Bug #54314)


File: manual.info,  Node: connector-odbc-news-5-1-7,  Next: connector-odbc-news-5-1-6,  Prev: connector-odbc-news-5-1-8,  Up: connector-odbc-news-5-1-x

D.3.1.3 Changes in MySQL Connector/ODBC 5.1.7 (24 August 2010)
..............................................................

*Functionality Added or Changed*

   * MySQL Connector/ODBC has been changed to support the
     `CLIENT_INTERACTIVE' flag.  (Bug #48603)

*Bugs Fixed*

   * `SQLColAttribute(SQL_DESC_PRECISION...)' function returned
     incorrect results for type identifiers that have a negative value:

          #define SQL_LONGVARCHAR       (-1) returned 4294967295
          #define SQL_BINARY            (-2) returned 4294967294
          #define SQL_VARBINARY         (-3) returned 4294967293
          #define SQL_LONGVARBINARY     (-4) returned 4294967292
          #define SQL_BIGINT            (-5) returned 4294967291
          #define SQL_TINYINT           (-6) returned 4294967290
          #define SQL_BIT               (-7) returned 4294967289

     They were returned as 32-bit unsigned integer values. This only
     happened on 64-bit Linux.  (Bug #55024)

   * `SQLColAttribute' for `SQL_DESC_OCTET_LENGTH' returned length
     including terminating null byte. It should not have included the
     null byte.  (Bug #54206)

   * The `SQLColumns' function returned the incorrect transfer octet
     length into the column `BUFFER_LENGTH' for `DECIMAL' type.  (Bug
     #53235)

   * `SQLForeignKeys()' did not return the correct information. The
     list of foreign keys in other tables should not have included
     foreign keys that point to unique constraints in the specified
     table.  (Bug #51422)

   * When executing the `SQLProcedureColumns()' ODBC function, the
     driver reported the following error:

          MySQL server does not provide the requested information

     (Bug #50400)

   * In contrast to all other ODBC catalog functions
     `SQLTablePrivileges' required the user to have `SELECT' privilege
     on MySQL schemata, otherwise the function returned with an error:

          SQL Error. Native Code: 1142, SQLState: HY000, Return Code: -1
          [MySQL][ODBC 5.1 Driver][mysqld-5.0.67-community-nt]SELECT command denied to user
          'repadmin'@'localhost' for table 'tables_priv'
          [Error][SQL Error]Error executing SQLTablePrivileges for object cat: myrep, object Name:
          xxxxxxxxxx

     (Bug #50195)

   * MySQL Connector/ODBC manually added a `LIMIT' clause to the end of
     certain SQL statements, causing errors for statements that
     contained code that should be positioned after the `LIMIT' clause.
     (Bug #49726)

   * If `NO_BACKSLASH_ESCAPES' mode was used on a server, escaping
     binary data led to server query parsing errors.  (Bug #49029)

   * Bulk upload operations did not work for queries that used
     parameters.  (Bug #48310)

   * Retrieval of the current catalog at the moment when a connection
     was not ready, such as when the connection had been broken or when
     not all pending results had been processed, resulted in the
     application crashing.  (Bug #46910)

   * Describing a view or table caused SQLPrepare to prefetch table
     data. For large tables this created an intolerable performance hit.
     (Bug #46411)

   * If an application was invoked by the root user,
     `SQLDriverConnect()' was not able to use the username and password
     in the connection string to connect to the database.  (Bug #45378)

   * Calling `SQLColAttribute' on a date column did not set
     `SQL_DESC_DATETIME_INTERVAL_CODE'.  `SQLColAttribute' returned
     `SQL_SUCCESS' but the integer passed in was not set to
     `SQL_CODE_DATE'.  (Bug #44576)

   * Conversions for many types were missing from the file
     `driver/info.c'.  (Bug #43855)

   * The `SQLTables()' function required approximately two to four
     minutes to return the list of 400 tables in a database. The `SHOW
     TABLE STATUS' query used by `SQLTables()' was extremely slow for
     InnoDB tables with a large number of rows because the query was
     calculating the approximate number of rows in each table.
     Further, the results could not be cached due to non-deterministic
     nature of the result set (the row count was re-calculated every
     time), impacting performance further.  (Bug #43664)

   * Executing `SQLForeignKeys' to get imported foreign keys for tables
     took an excessively long time. For example, getting imported
     foreign keys for 252 tables to determine parent/child dependencies
     took about 3 minutes and 14 seconds for the 5.1.5 driver, whereas
     it took 3 seconds for the 3.5x.x driver.  (Bug #39562)

   * `SQLDescribeCol' returned incorrect column definitions for
     `SQLTables' result.  (Bug #37621)

   * When opening `ADO.Recordset' from Microsoft Access 2003, a
     run-time error occurred:

          ErrNo: -2147467259 ErrMessage: Data provider or other service returned an E_FAIL status.

     (Bug #36996)

   * `SQLPrimaryKeysW' returned mangled strings for table name, column
     name and primary key name.  (Bug #36441)

   * On Windows, the SOCKET parameter to the DSN was used as the named
     pipe name to connect to. This was not exposed in the Windows setup
     GUI.  (Bug #34477)

   * MySQL Connector/ODBC returned a value of zero for a column with a
     non-zero value. This happened when the column had a data type of
     `BIT', and any numeric type was used in `SQLBindCol'.  (Bug #32821)

   * Option for handling bad dates was not available in the GUI.  (Bug
     #30539)


File: manual.info,  Node: connector-odbc-news-5-1-6,  Next: connector-odbc-news-5-1-5,  Prev: connector-odbc-news-5-1-7,  Up: connector-odbc-news-5-1-x

D.3.1.4 Changes in MySQL Connector/ODBC 5.1.6 (09 November 2009)
................................................................

*Functionality Added or Changed*

   * In the MySQL Data Source Configuration dialog, an excessive number
     of tabs were required to navigate to selection of a database.
     MySQL Connector/ODBC has been changed to make the tab order more
     practical, thereby enabling faster configuration of a Data Source.
     (Bug #42905)

*Bugs Fixed*

   * An error randomly occurred on Windows 2003 Servers (German
     language Version) serving classic ASP scripts on IIS6 MDAC version
     2.8 SP2 on Windows 2003 SP2. The application connected to MySQL
     Server 5.0.44-log with a charset of UTF-8 Unicode (utf8). The
     MySQL server was running on Gentoo Linux.

     The script error occurred sporadically on the following line of
     code:

          SET my_conn = Server.CreateObject("ADODB.Connection")
          my_conn.Open ConnString  <- ERROR

     The connection was either a DSN or the explicit connection string:

          Driver={MySQL ODBC 5.1 Driver};SERVER=abc.abc.abc.abc;DATABASE=dbname;UID=uidname;PWD=pwdname;PORT=3306;OPTION=67108864;

     The error occurred on connections established using either a DNS
     or a connection string.

     When IISState and Debug Diagnostic Tool 1.0.0.152 was used to
     analyse the code, the following crash analysis was generated:

          MYODBC5!UTF16TOUTF32+6In 4640-1242788336.dmp the assembly instruction at
          myodbc5!utf16toutf32+6 in C:\Programme\MySQL\Connector ODBC 5.1\myodbc5.dll from MySQL AB
          has caused an access violation exception (0xC0000005) when trying to read from memory
          location 0x194dd000 on thread 33

     (Bug #44971)

   * MySQL Connector/ODBC overwrote the query log. MySQL Connector/ODBC
     was changed to append the log, rather than overwrite it.  (Bug
     #44965)

   * MySQL Connector/ODBC failed to build with MySQL 5.1.30 due to
     incorrect use of the data type `bool'.  (Bug #42120)

   * Inserting a new record using `SQLSetPos' did not correspond to the
     database name specified in the `SELECT' statement when querying
     tables from databases other than the current one.

     `SQLSetPos' attempted to do the `INSERT' in the current database,
     but finished with a `SQL_ERROR' result and `Table does not exist'
     message from MySQL Server.  (Bug #41946)

   * Calling `SQLDescribeCol()' with a NULL buffer and nonzero buffer
     length caused a crash.  (Bug #41942)

   * MySQL Connector/ODBC updated some fields with random values,
     rather than with `NULL'.  (Bug #41256)

   * When a column of type `DECIMAL' containing `NULL' was accessed,
     MySQL Connector/ODBC returned a 0 rather than a `NULL'.  (Bug
     #41081)

   * In Access 97, when linking a table containing a `LONGTEXT' or
     `TEXT' field to a MySQL Connector/ODBC DSN, the fields were shown
     as `TEXT(255)' in the table structure. Data was therefore
     truncated to 255 characters.  (Bug #40932)

   * Calling `SQLDriverConnect()' with a `NULL' pointer for the output
     buffer caused a crash if `SQL_DRIVER_NOPROMPT' was also specified:

          SQLDriverConnect(dbc, NULL, "DSN=myodbc5", SQL_NTS, NULL, 0, NULL, SQL_DRIVER_NOPROMPT)

     (Bug #40316)

   * Setting the ADO `Recordset' decimal field value to 44.56 resulted
     in an incorrect value of 445600.0000 being stored when the record
     set was updated with the `Update' method.  (Bug #39961)

   * The `SQLTablesW' API gave incorrect results.  For example, table
     name and table type were returned as `NULL' rather than as the
     correct values.  (Bug #39957)

   * Connector/ODBC would crash when a character set was being used on
     the server that was not supported in the client, for example
     cp1251:

          [MySQL][ODBC 5.1 Driver][mysqld-5.0.27-community-nt]Restricted data type attribute violation

     The fix causes Connector/ODBC to return an error message instead
     of crashing.  (Bug #39831)

   * Binding `SQL_C_BIT' to an `INTEGER' column did not work.

     The `sql_get_data()' function only worked correctly for `BOOLEAN'
     columns that corresponded to `SQL_C_BIT' buffers.  (Bug #39644)

   * When the SQLTables method was called with `NULL' passed as the
     `tablename' parameter, only one row in the `resultset', with table
     name of `NULL' was returned, instead of all tables for the given
     database.  (Bug #39561)

   * The `SQLGetInfo()' function returned 0 for `SQL_CATALOG_USAGE'
     information.  (Bug #39560)

   * Connector/ODBC 5.1.5 was not able to connect if the connection
     string parameters contained spaces or tab symbols. For example, if
     the `SERVER' parameter was specified as `SERVER= localhost'
     instead of `SERVER=localhost' the following error message will be
     displayed:

          [MySQL][ODBC 5.1 Driver] Unknown MySQL server host ' localhost' (11001).

     (Bug #39085)

   * The pointer passed to the SQLDriverConnect method to retrieve the
     output connection string length was one greater than it should
     have been due to the inclusion of the NULL terminator.  (Bug
     #38949)

   * Data-at-execution parameters were not supported during positioned
     update. This meant updating a long text field with a cursor update
     would erroneously set the value to null. This would lead to the
     error `Column 'column_name' cannot be null' while updating the
     database, even when `column_name' had been assigned a valid nonnull
     string.  (Bug #37649)

   * The SQLDriverConnect method truncated the `OutputConnectionString'
     parameter to 52 characters.  (Bug #37278)

   * The connection string option `Enable Auto-reconnect' did not work.
     When the connection failed, it could not be restored, and the
     errors generated were the same as if the option had not been
     selected.  (Bug #37179)

   * Insertion of data into a `LONGTEXT' table field did not work. If
     such an attempt was made the corresponding field would be found to
     be empty on examination, or contain random characters.  (Bug
     #36071)

   * No result record was returned for `SQLGetTypeInfo' for the
     `TIMESTAMP' data type. An application would receive the result
     `return code 100 (SQL_NO_DATA_FOUND)'.  (Bug #30626)

   * It was not possible to use MySQL Connector/ODBC to connect to a
     server using SSL. The following error was generated:

          Runtime error '-2147467259 (80004005)':

          [MySQL][ODBC 3.51 Driver]SSL connection error.

     (Bug #29955)

   * When the `recordSet.Update' function was called to update an
     `adLongVarChar' field, the field was updated but the recordset was
     immediately lost. This happened with driver cursors, whether the
     cursor was opened in optimistic or pessimistic mode.

     When the next update was called the test code would exit with the
     following error:

          -2147467259 : Query-based update failed because the row to update could not be found.

     (Bug #26950)

   * Microsoft Access was not able to read `BIGINT' values properly
     from a table with just two columns of type `BIGINT' and `VARCHAR'.
     `#DELETE' appeared instead of the correct values.  (Bug #17679)


File: manual.info,  Node: connector-odbc-news-5-1-5,  Next: connector-odbc-news-5-1-4,  Prev: connector-odbc-news-5-1-6,  Up: connector-odbc-news-5-1-x

D.3.1.5 Changes in MySQL Connector/ODBC 5.1.5 (18 August 2008)
..............................................................

*Bugs Fixed*

   * ODBC *Note `TIMESTAMP': datetime. string format is not handled
     properly by Connector/ODBC. When passing a *Note `TIMESTAMP':
     datetime. or *Note `DATE': datetime. to Connector/ODBC, in the
     ODBC format: {d <date>} or {ts <timestamp>}, the string that
     represents this is copied once into the SQL statement, and then
     added again, as an escaped string.  (Bug #37342)

   * The connector failed to prompt for additional information required
     to create a DSN-less connection from an application such as
     Microsoft Excel.  (Bug #37254)

   * `SQLDriverConnect' does not return `SQL_NO_DATA' on cancel. The
     ODBC documentation specifies that this method should return
     `SQL_NO_DATA' when the user cancels the dialog to connect. The
     connector, however, returns `SQL_ERROR'.  (Bug #36293)

   * Assigning a string longer than 67 characters to the `TableType'
     parameter resulted in a buffer overrun when the `SQLTables()'
     function was called.  (Bug #36275)

   * The ODBC connector randomly uses logon information stored in
     `odbc-profile', or prompts the user for connection information and
     ignores any settings stored in `odbc-profile'.  (Bug #36203)

   * After having successfully established a connection, a crash occurs
     when calling `SQLProcedures()' followed by `SQLFreeStmt()', using
     the ODBC C API.  (Bug #36069)


File: manual.info,  Node: connector-odbc-news-5-1-4,  Next: connector-odbc-news-5-1-3,  Prev: connector-odbc-news-5-1-5,  Up: connector-odbc-news-5-1-x

D.3.1.6 Changes in MySQL Connector/ODBC 5.1.4 (15 April 2008)
.............................................................

*Bugs Fixed*

   * Wrong result obtained when using `sum()' on a `decimal(8,2)' field
     type.  (Bug #35920)

   * The driver installer could not create a new DSN if many other
     drivers were already installed.  (Bug #35776)

   * The `SQLColAttribute()' function returned `SQL_TRUE' when querying
     the `SQL_DESC_FIXED_PREC_SCALE (SQL_COLUMN_MONEY)' attribute of a
     *Note `DECIMAL': numeric-types. column.  Previously, the correct
     value of `SQL_FALSE' was returned; this is now again the case.
     (Bug #35581)

   * On Linux, `SQLGetDiagRec()' returned `SQL_SUCCESS' in cases when
     it should have returned `SQL_NO_DATA'.  (Bug #33910)

   * The driver crashes ODBC Administrator on attempting to add a new
     DSN.  (Bug #32057)


File: manual.info,  Node: connector-odbc-news-5-1-3,  Next: connector-odbc-news-5-1-2,  Prev: connector-odbc-news-5-1-4,  Up: connector-odbc-news-5-1-x

D.3.1.7 Changes in MySQL Connector/ODBC 5.1.3 (26 March 2008)
.............................................................

*Platform-Specific Notes*

   * *Important Change*: You must uninstall previous 5.1.x editions of
     MySQL Connector/ODBC before installing the new version.

   * The HP-UX 11.23 IA64 binary package does not include the GUI bits
     because of problems building Qt on that platform.

   * There is no binary package for Mac OS X on 64-bit PowerPC because
     Apple does not currently provide a 64-bit PowerPC version of iODBC.

   * The installer for 64-bit Windows installs both the 32-bit and
     64-bit driver. Please note that Microsoft does not yet supply a
     64-bit bridge from ADO to ODBC.

*Bugs Fixed*

   * *Important Change*: In previous versions, the SSL certificate
     would automatically be verified when used as part of the MySQL
     Connector/ODBC connection. The default mode is now to ignore the
     verificate of certificates. To enforce verification of the SSL
     certificate during connection, use the `SSLVERIFY' DSN parameter,
     setting the value to 1.  (Bug #29955, Bug #34648)

   * Inserting characters to a UTF8 table using surrogate pairs would
     fail and insert invalid data.  (Bug #34672)

   * Installation of MySQL Connector/ODBC would fail because it was
     unable to uninstall a previous installed version. The file being
     requested would match an older release version than any installed
     version of the connector.  (Bug #34522)

   * Using `SqlGetData' in combination with `SQL_C_WCHAR' would return
     overlapping data.  (Bug #34429)

   * Descriptor records were not cleared correctly when calling
     `SQLFreeStmt(SQL_UNBIND)'.  (Bug #34271)

   * The dropdown selection for databases on a server when creating a
     DSN was too small. The list size now automatically adjusts up to a
     maximum size of 20 potential databases.  (Bug #33918)

   * Microsoft Access would be unable to use
     `DBEngine.RegisterDatabase' to create a DSN using the MySQL
     Connector/ODBC driver.  (Bug #33825)

   * MySQL Connector/ODBC erroneously reported that it supported the
     `CAST()' and `CONVERT()' ODBC functions for parsing values in SQL
     statements, which could lead to bad SQL generation during a query.
     (Bug #33808)

   * Using a linked table in Access 2003 where the table has a *Note
     `BIGINT': numeric-types. column as the first column in the table,
     and is configured as the primary key, shows `#DELETED' for all
     rows of the table.  (Bug #24535)

   * Updating a `RecordSet' when the query involves a *Note `BLOB':
     blob. field would fail.  (Bug #19065)


File: manual.info,  Node: connector-odbc-news-5-1-2,  Next: connector-odbc-news-5-1-1,  Prev: connector-odbc-news-5-1-3,  Up: connector-odbc-news-5-1-x

D.3.1.8 Changes in MySQL Connector/ODBC 5.1.2 (13 February 2008)
................................................................

MySQL Connector/ODBC 5.1.2-beta, a new version of the ODBC driver for
the MySQL database management system, has been released. This release
is the second beta (feature-complete) release of the new 5.1 series and
is suitable for use with any MySQL server version since MySQL 4.1,
including MySQL 5.0, 5.1, and 6.0. (It will not work with 4.0 or
earlier releases.)

Keep in mind that this is a beta release, and as with any other
pre-production release, caution should be taken when installing on
production level systems or systems with critical data.

*Platform-Specific Notes*

   * The HP-UX 11.23 IA64 binary package does not include the GUI bits
     because of problems building Qt on that platform.

   * There is no binary package for Mac OS X on 64-bit PowerPC because
     Apple does not currently provide a 64-bit PowerPC version of iODBC.

   * The installer for 64-bit Windows installs both the 32-bit and
     64-bit driver. Please note that Microsoft does not yet supply a
     64-bit bridge from ADO to ODBC.

   * Due to differences with the installation process used on Windows
     and potential registry corruption, it is recommended that
     uninstall any existing versions of MySQL Connector/ODBC 5.1.x
     before upgrading.

     See also Bug #34571.

*Functionality Added or Changed*

   * Explicit descriptors are implemented.  (Bug #32064)

   * A full implementation of SQLForeignKeys based on the information
     available from INFORMATION_SCHEMA in 5.0 and later versions of the
     server has been implemented.

   * Changed `SQL_ATTR_PARAMSET_SIZE' to return an error until support
     for it is implemented.

   * Disabled `MYSQL_OPT_SSL_VERIFY_SERVER_CERT' when using an SSL
     connection.

   * `SQLForeignKeys' uses `INFORMATION_SCHEMA' when it is available on
     the server, which enables more complete information to be returned.

*Bugs Fixed*

   * The `SSLCIPHER' option would be incorrectly recorded within the
     SSL configuration on Windows.  (Bug #33897)

   * Within the GUI interface, when connecting to a MySQL server on a
     nonstandard port, the connection test within the GUI would fail.
     The issue was related to incorrect parsing of numeric values
     within the DSN when the option was not configured as the last
     parameter within the DSN.  (Bug #33822)

   * Specifying a nonexistent database name within the GUI dialog would
     result in an empty list, not an error.  (Bug #33615)

   * When deleting rows from a static cursor, the cursor position would
     be incorrectly reported.  (Bug #33388)

   * `SQLGetInfo()' reported characters for `SQL_SPECIAL_CHARACTERS'
     that were not encoded correctly.  (Bug #33130)

   * Retrieving data from a *Note `BLOB': blob.  column would fail
     within `SQLGetData'when the target data type was `SQL_C_WCHAR' due
     to incorrect handling of the character buffer.  (Bug #32684)

   * Renaming an existing DSN entry would create a new entry with the
     new name without deleting the old entry.  (Bug #31165)

   * Reading a *Note `TEXT': blob. column that had been used to store
     UTF8 data would result in the wrong information being returned
     during a query.  (Bug #28617)

   * `SQLForeignKeys' would return an empty string for the schema
     columns instead of `NULL'.  (Bug #19923)

   * When accessing column data, `FLAG_COLUMN_SIZE_S32' did not limit
     the octet length or display size reported for fields, causing
     problems with Microsoft Visual FoxPro.

     The list of ODBC functions that could have caused failures in
     Microsoft software when retrieving the length of *Note `LONGBLOB':
     blob. or *Note `LONGTEXT': blob. columns includes:

        * `SQLColumns'

        * `SQLColAttribute'

        * `SQLColAttributes'

        * `SQLDescribeCol'

        * `SQLSpecialColumns' (theoretically can have the same problem)

     (Bug #12805, Bug #30890)

   * Dynamic cursors on statements with parameters were not supported.
     (Bug #11846)

   * Evaluating a simple numeric expression when using the OLEDB for
     ODBC provider and ADO would return an error, instead of the result.
     (Bug #10128)

   * Adding or updating a row using `SQLSetPos()' on a result set with
     aliased columns would fail.  (Bug #6157)


File: manual.info,  Node: connector-odbc-news-5-1-1,  Next: connector-odbc-news-5-1-0,  Prev: connector-odbc-news-5-1-2,  Up: connector-odbc-news-5-1-x

D.3.1.9 Changes in MySQL Connector/ODBC 5.1.1 (13 December 2007)
................................................................

MySQL Connector/ODBC 5.1.1-beta, a new version of the ODBC driver for
the MySQL database management system, has been released. This release
is the first beta (feature-complete) release of the new 5.1 series and
is suitable for use with any MySQL server version since MySQL 4.1,
including MySQL 5.0, 5.1, and 6.0. (It will not work with 4.0 or
earlier releases.)

Keep in mind that this is a beta release, and as with any other
pre-production release, caution should be taken when installing on
production level systems or systems with critical data.

Includes changes from *Note Connector/ODBC 3.51.21:
connector-odbc-news-3-51-21. and *Note 3.51.22:
connector-odbc-news-3-51-22.

Built using MySQL 5.0.52.

*Platform-Specific Notes*

   * The HP-UX 11.23 IA64 binary package does not include the GUI bits
     because of problems building Qt on that platform.

   * There is no binary package for Mac OS X on 64-bit PowerPC because
     Apple does not currently provide a 64-bit PowerPC version of iODBC.

   * The installer for 64-bit Windows installs both the 32-bit and
     64-bit driver. Please note that Microsoft does not yet supply a
     64-bit bridge from ADO to ODBC.

   * Due to differences with the installation process used on Windows
     and potential registry corruption, it is recommended that
     uninstall any existing versions of MySQL Connector/ODBC 5.1.x
     before upgrading.

     See also Bug #34571.

*Functionality Added or Changed*

   * *Incompatible Change*: Replaced myodbc3i (now myodbc-installer)
     with MySQL Connector/ODBC 5.0 version.

   * *Incompatible Change*: Removed monitor (myodbc3m) and dsn-editor
     (myodbc3c).

   * *Incompatible Change*: Do not permit `SET NAMES' in initial
     statement and in executed statements.

   * A wrapper for the `SQLGetPrivateProfileStringW()' function, which
     is required for Unicode support, has been created. This function
     is missing from the unixODBC driver manager.  (Bug #32685)

   * Added MSI installer for Windows 64-bit.  (Bug #31510)

   * Implemented support for `SQLCancel()'.  (Bug #15601)

   * Added support for `SQL_NUMERIC_STRUCT'.  (Bug #3028, Bug #24920)

   * Removed nonthreadsafe configuration of the driver. The driver is
     now always built against the threadsafe version of libmysql.

   * Implemented native Windows setup library

   * Replaced the internal library which handles creation and loading
     of DSN information. The new library, which was originally a part
     of MySQL Connector/ODBC 5.0, supports Unicode option values.

   * The Windows installer now places files in a subdirectory of the
     `Program Files' directory instead of the Windows system directory.

*Bugs Fixed*

   * The `SET NAMES' statement has been disabled because it causes
     problems in the ODBC driver when determining the current client
     character set.  (Bug #32596)

   * `SQLDescribeColW' returned UTF-8 column as `SQL_VARCHAR' instead of
     `SQL_WVARCHAR'.  (Bug #32161)

   * ADO was unable to open record set using dynamic cursor.  (Bug
     #32014)

   * ADO applications would not open a `RecordSet' that contained a
     *Note `DECIMAL': numeric-types. field.  (Bug #31720)

   * Memory usage would increase considerably.  (Bug #31115)

   * SQL statements are limited to 64KB.  (Bug #30983, Bug #30984)

   * `SQLSetPos' with `SQL_DELETE' advances dynamic cursor incorrectly.
     (Bug #29765)

   * Using an ODBC prepared statement with bound columns would produce
     an empty result set when called immediately after inserting a row
     into a table.  (Bug #29239)

   * ADO Not possible to update a client side cursor.  (Bug #27961)

   * Recordset `Update()' fails when using `adUseClient' cursor.  (Bug
     #26985)

   * MySQL Connector/ODBC would fail to connect to the server if the
     password contained certain characters, including the semicolon and
     other punctuation marks.  (Bug #16178)

   * Fixed `SQL_ATTR_PARAM_BIND_OFFSET', and fixed row offsets to work
     with updatable cursors.

   * `SQLSetConnectAttr()' did not clear previous errors, possibly
     confusing `SQLError()'.

   * `SQLError()' incorrectly cleared the error information, making it
     unavailable from subsequent calls to `SQLGetDiagRec()'.

   * NULL pointers passed to `SQLGetInfo()' could result in a crash.

   * `SQL_ODBC_SQL_CONFORMANCE' was not handled by `SQLGetInfo()'.

   * `SQLCopyDesc()' did not correctly copy all records.

   * Diagnostics were not correctly cleared on connection and
     environment handles.


File: manual.info,  Node: connector-odbc-news-5-1-0,  Prev: connector-odbc-news-5-1-1,  Up: connector-odbc-news-5-1-x

D.3.1.10 Changes in MySQL Connector/ODBC 5.1.0 (10 September 2007)
..................................................................

This release is the first of the new 5.1 series and is suitable for use
with any MySQL server version since MySQL 4.1, including MySQL 5.0,
5.1, and 6.0. (It will not work with 4.0 or earlier releases.)

Keep in mind that this is a alpha release, and as with any other
pre-production release, caution should be taken when installing on
production level systems or systems with critical data. Not all of the
features planned for the final Connector/ODBC 5.1 release are
implemented.

Functionality is based on Connector/ODBC 3.51.20.

*Platform-Specific Notes*

   * The HP-UX 11.23 IA64 binary package does not include the GUI bits
     because of problems building Qt on that platform.

   * There is no binary package for Mac OS X on 64-bit PowerPC because
     Apple does not currently provide a 64-bit PowerPC version of iODBC.

   * There are no installer packages for Microsoft Windows x64 Edition.

   * Due to differences with the installation process used on Windows
     and potential registry corruption, it is recommended that
     uninstall any existing versions of MySQL Connector/ODBC 5.1.x
     before upgrading.

     See also Bug #34571.

*Functionality Added or Changed*

   * Added support for Unicode functions (`SQLConnectW', etc).

   * Added descriptor support (`SQLGetDescField', `SQLGetDescRec', etc).

   * Added support for `SQL_C_WCHAR'.


File: manual.info,  Node: connector-odbc-news-5-0-x,  Next: connector-odbc-news-3-51-x,  Prev: connector-odbc-news-5-1-x,  Up: connector-odbc-news

D.3.2 Changes in MySQL Connector/ODBC Version 5.0.x
---------------------------------------------------

* Menu:

* connector-odbc-news-5-0-12::   Changes in MySQL Connector/ODBC 5.0.12 (Never released)
* connector-odbc-news-5-0-11::   Changes in MySQL Connector/ODBC 5.0.11 (31 January 2007)
* connector-odbc-news-5-0-10::   Changes in MySQL Connector/ODBC 5.0.10 (14 December 2006)
* connector-odbc-news-5-0-9::    Changes in MySQL Connector/ODBC 5.0.9 (22 November 2006)
* connector-odbc-news-5-0-8::    Changes in MySQL Connector/ODBC 5.0.8 (17 November 2006)
* connector-odbc-news-5-0-7::    Changes in MySQL Connector/ODBC 5.0.7 (08 November 2006)
* connector-odbc-news-5-0-6::    Changes in MySQL Connector/ODBC 5.0.6 (03 November 2006)
* connector-odbc-news-5-0-5::    Changes in MySQL Connector/ODBC 5.0.5 (17 October 2006)
* connector-odbc-news-5-0-3::    Changes in Connector/ODBC 5.0.3 (Connector/ODBC 5.0 Alpha 3) (20 June 2006)
* connector-odbc-news-5-0-2::    Changes in Connector/ODBC 5.0.2 (Never released)
* connector-odbc-news-5-0-1::    Changes in Connector/ODBC 5.0.1 (Connector/ODBC 5.0 Alpha 2) (05 June 2006)


File: manual.info,  Node: connector-odbc-news-5-0-12,  Next: connector-odbc-news-5-0-11,  Prev: connector-odbc-news-5-0-x,  Up: connector-odbc-news-5-0-x

D.3.2.1 Changes in MySQL Connector/ODBC 5.0.12 (Never released)
...............................................................

*Note*:

Development on Connector/ODBC 5.0.x has ceased. New features and
functionality will be incorporated into Connector/ODBC 5.1.

*Bugs Fixed*

   * Inserting `NULL' values into a *Note `DATETIME': datetime. column
     from Access reports an error.  (Bug #27896)

   * Tables with *Note `TEXT': blob. columns would be incorrectly
     identified, returning an `Unknown SQL type - 65535' error.  (Bug
     #20127)


File: manual.info,  Node: connector-odbc-news-5-0-11,  Next: connector-odbc-news-5-0-10,  Prev: connector-odbc-news-5-0-12,  Up: connector-odbc-news-5-0-x

D.3.2.2 Changes in MySQL Connector/ODBC 5.0.11 (31 January 2007)
................................................................

*Functionality Added or Changed*

   * Added support for ODBC v2 statement options using attributes.

   * Driver now builds and is partially tested under Linux with the
     iODBC driver manager.

*Bugs Fixed*

   * Connection string parsing for DSN-less connections could fail to
     identify some parameters.  (Bug #25316)

   * Updates of `MEMO' or *Note `TEXT': blob. columns from within
     Microsoft Access would fail.  (Bug #25263)

   * Transaction support has been added and tested.  (Bug #25045)

   * Internal function, `my_setpos_delete_ignore()' could cause a crash.
     (Bug #22796)

   * Fixed occasional mis-handling of the `SQL_NUMERIC_C' type.

   * Fixed the binding of certain integer types.


File: manual.info,  Node: connector-odbc-news-5-0-10,  Next: connector-odbc-news-5-0-9,  Prev: connector-odbc-news-5-0-11,  Up: connector-odbc-news-5-0-x

D.3.2.3 Changes in MySQL Connector/ODBC 5.0.10 (14 December 2006)
.................................................................

Connector/ODBC 5.0.10 is the sixth BETA release.

*Functionality Added or Changed*

   * Significant performance improvement when retrieving large text
     fields in pieces using `SQLGetData()' with a buffer smaller than
     the whole data. Mainly used in Access when fetching very large
     text fields.  (Bug #24876)

   * Added initial unicode support in data and metadata.  (Bug #24837)

   * Added initial support for removing braces when calling stored
     procedures and retrieving result sets from procedure calls.  (Bug
     #24485)

   * Added loose handling of retrieving some diagnostic data.  (Bug
     #15782)

   * Added wide-string type info for `SQLGetTypeInfo()'.

*Bugs Fixed*

   * Editing DSN no longer crashes ODBC data source administrator.
     (Bug #24675)

   * String query parameters are new escaped correctly.  (Bug #19078)


File: manual.info,  Node: connector-odbc-news-5-0-9,  Next: connector-odbc-news-5-0-8,  Prev: connector-odbc-news-5-0-10,  Up: connector-odbc-news-5-0-x

D.3.2.4 Changes in MySQL Connector/ODBC 5.0.9 (22 November 2006)
................................................................

Connector/ODBC 5.0.9 is the fifth BETA release.

This is an implementation and testing release, and is not designed for
use within a production environment.

*Functionality Added or Changed*

   * Added support for column binding as SQL_NUMERIC_STRUCT.

   * Added recognition of `SQL_C_SHORT' and `SQL_C_TINYINT' as C types.

*Bugs Fixed*

   * Fixed wildcard handling of and listing of catalogs and tables in
     `SQLTables'.

   * Added limit of display size when requested using
     `SQLColAttribute'/`SQL_DESC_DISPLAY_SIZE'.

   * Fixed buffer length return for SQLDriverConnect.

   * ODBC v2 behavior in driver now supports ODBC v3 date/time types
     (since DriverManager maps them).

   * Catch use of `SQL_ATTR_PARAMSET_SIZE' and report error until we
     fully support.

   * Fixed statistics to fail if it couldn't be completed.

   * Corrected retrieval multiple field types bit and blob/text.

   * Fixed SQLGetData to clear the NULL indicator correctly during
     multiple calls.


File: manual.info,  Node: connector-odbc-news-5-0-8,  Next: connector-odbc-news-5-0-7,  Prev: connector-odbc-news-5-0-9,  Up: connector-odbc-news-5-0-x

D.3.2.5 Changes in MySQL Connector/ODBC 5.0.8 (17 November 2006)
................................................................

Connector/ODBC 5.0.8 is the fourth BETA release.

This is an implementation and testing release, and is not designed for
use within a production environment.

*Functionality Added or Changed*

   * Also made `SQL_DESC_NAME' only fill in the name if there was a
     data pointer given, otherwise just the length.

   * Fixed display size to be length if max length isn't available.

   * Made distinction between *Note `CHAR': char./*Note `BINARY':
     binary-varbinary.  (and VAR versions).

   * Wildcards now support escaped chars and underscore matching
     (needed to link tables with underscores in access).

*Bugs Fixed*

   * Fixed binding using `SQL_C_LONG'.

   * Fixed using wrong pointer for `SQL_MAX_DRIVER_CONNECTIONS' in
     `SQLGetInfo'.

   * Set default return to `SQL_SUCCESS' if nothing is done for
     `SQLSpecialColumns'.

   * Fixed MDiagnostic to use correct v2/v3 error codes.

   * Allow SQLDescribeCol to be called to retrieve the length of the
     column name, but not the name itself.

   * Length now used when handling bind parameter (needed in particular
     for `SQL_WCHAR') - this enables updating char data in MS Access.

   * Updated retrieval of descriptor fields to use the right pointer
     types.

   * Fixed handling of numeric pointers in SQLColAttribute.

   * Fixed type returned for `MYSQL_TYPE_LONG' to `SQL_INTEGER' instead
     of `SQL_TINYINT'.

   * Fix size return from `SQLDescribeCol'.

   * Fixed string length to chars, not bytes, returned by SQLGetDiagRec.


File: manual.info,  Node: connector-odbc-news-5-0-7,  Next: connector-odbc-news-5-0-6,  Prev: connector-odbc-news-5-0-8,  Up: connector-odbc-news-5-0-x

D.3.2.6 Changes in MySQL Connector/ODBC 5.0.7 (08 November 2006)
................................................................

Connector/ODBC 5.0.7 is the third BETA release.

This is an implementation and testing release, and is not designed for
use within a production environment.

*Functionality Added or Changed*

   * Added support for `SQLStatistics' to `MYODBCShell'.

   * Improved trace/log.

*Bugs Fixed*

   * SQLBindParameter now handles `SQL_C_DEFAULT'.

   * Corrected incorrect column index within `SQLStatistics'. Many more
     tables can now be linked into MS Access.

   * Fixed `SQLDescribeCol' returning column name length in bytes
     rather than chars.


File: manual.info,  Node: connector-odbc-news-5-0-6,  Next: connector-odbc-news-5-0-5,  Prev: connector-odbc-news-5-0-7,  Up: connector-odbc-news-5-0-x

D.3.2.7 Changes in MySQL Connector/ODBC 5.0.6 (03 November 2006)
................................................................

Connector/ODBC 5.0.6 is the second BETA release.

This is an implementation and testing release, and is not designed for
use within a production environment.

*Features, Limitations, and Notes on this Release*
   * MySQL Connector/ODBC supports both `User' and `System' DSNs.

   * Installation is provided in the form of a standard Microsoft
     System Installer (MSI).

   * You no longer have to have MySQL Connector/ODBC 3.51 installed
     before installing this version.

*Bugs Fixed*

   * You no longer have to have MySQL Connector/ODBC 3.51 installed
     before installing this version.

   * MySQL Connector/ODBC supports both `User' and `System' DSNs.

   * Installation is provided in the form of a standard Microsoft
     System Installer (MSI).


File: manual.info,  Node: connector-odbc-news-5-0-5,  Next: connector-odbc-news-5-0-3,  Prev: connector-odbc-news-5-0-6,  Up: connector-odbc-news-5-0-x

D.3.2.8 Changes in MySQL Connector/ODBC 5.0.5 (17 October 2006)
...............................................................

Connector/ODBC 5.0.5 is the first BETA release.

This is an implementation and testing release, and is not designed for
use within a production environment.

You no longer have to have Connector/ODBC 3.51 installed before
installing this version.

*Bugs Fixed*

   * You no longer have to have MySQL Connector/ODBC 3.51 installed
     before installing this version.


File: manual.info,  Node: connector-odbc-news-5-0-3,  Next: connector-odbc-news-5-0-2,  Prev: connector-odbc-news-5-0-5,  Up: connector-odbc-news-5-0-x

D.3.2.9 Changes in Connector/ODBC 5.0.3 (Connector/ODBC 5.0 Alpha 3) (20 June 2006)
...................................................................................

This is an implementation and testing release, and is not designed for
use within a production environment.

Features, limitations and notes on this release:

   * The following ODBC API functions have been added in this release:

        * `SQLBindParameter'

        * `SQLBindCol'


File: manual.info,  Node: connector-odbc-news-5-0-2,  Next: connector-odbc-news-5-0-1,  Prev: connector-odbc-news-5-0-3,  Up: connector-odbc-news-5-0-x

D.3.2.10 Changes in Connector/ODBC 5.0.2 (Never released)
.........................................................

Connector/ODBC 5.0.2 was an internal implementation and testing release.


File: manual.info,  Node: connector-odbc-news-5-0-1,  Prev: connector-odbc-news-5-0-2,  Up: connector-odbc-news-5-0-x

D.3.2.11 Changes in Connector/ODBC 5.0.1 (Connector/ODBC 5.0 Alpha 2) (05 June 2006)
....................................................................................

Features, limitations and notes on this release:

   * Connector/ODBC 5.0 is Unicode aware.

   * Connector/ODBC is currently limited to basic applications.  ADO
     applications and Microsoft Office are not supported.

   * Connector/ODBC must be used with a Driver Manager.

   * The following ODBC API functions are implemented:

        * `SQLAllocHandle'

        * `SQLCloseCursor'

        * `SQLColAttribute'

        * `SQLColumns'

        * `SQLConnect'

        * `SQLCopyDesc'

        * `SQLDisconnect'

        * `SQLExecDirect'

        * `SQLExecute'

        * `SQLFetch'

        * `SQLFreeHandle'

        * `SQLFreeStmt'

        * `SQLGetConnectAttr'

        * `SQLGetData'

        * `SQLGetDescField'

        * `SQLGetDescRec'

        * `SQLGetDiagField'

        * `SQLGetDiagRec'

        * `SQLGetEnvAttr'

        * `SQLGetFunctions'

        * `SQLGetStmtAttr'

        * `SQLGetTypeInfo'

        * `SQLNumResultCols'

        * `SQLPrepare'

        * `SQLRowcount'

        * `SQLTables'

     The following ODBC API function are implemented, but not yet
     support all the available attributes/options:

        * `SQLSetConnectAttr'

        * `SQLSetDescField'

        * `SQLSetDescRec'

        * `SQLSetEnvAttr'

        * `SQLSetStmtAttr'


File: manual.info,  Node: connector-odbc-news-3-51-x,  Prev: connector-odbc-news-5-0-x,  Up: connector-odbc-news

D.3.3 Changes in MySQL Connector/ODBC Version 3.51.x
----------------------------------------------------

* Menu:

* connector-odbc-news-3-51-29::  Changes in MySQL Connector/ODBC 3.51.29 (04 October 2011)
* connector-odbc-news-3-51-28::  Changes in MySQL Connector/ODBC 3.51.28 (09 February 2011)
* connector-odbc-news-3-51-27::  Changes in MySQL Connector/ODBC 3.51.27 (20 November 2008)
* connector-odbc-news-3-51-26::  Changes in MySQL Connector/ODBC 3.51.26 (07 July 2008)
* connector-odbc-news-3-51-25::  Changes in MySQL Connector/ODBC 3.51.25 (11 April 2008)
* connector-odbc-news-3-51-24::  Changes in MySQL Connector/ODBC 3.51.24 (14 March 2008)
* connector-odbc-news-3-51-23::  Changes in MySQL Connector/ODBC 3.51.23 (09 January 2008)
* connector-odbc-news-3-51-22::  Changes in MySQL Connector/ODBC 3.51.22 (13 November 2007)
* connector-odbc-news-3-51-21::  Changes in MySQL Connector/ODBC 3.51.21 (08 October 2007)
* connector-odbc-news-3-51-20::  Changes in MySQL Connector/ODBC 3.51.20 (10 September 2007)
* connector-odbc-news-3-51-19::  Changes in MySQL Connector/ODBC 3.51.19 (10 August 2007)
* connector-odbc-news-3-51-18::  Changes in MySQL Connector/ODBC 3.51.18 (08 August 2007)
* connector-odbc-news-3-51-17::  Changes in MySQL Connector/ODBC 3.51.17 (14 July 2007)
* connector-odbc-news-3-51-16::  Changes in MySQL Connector/ODBC 3.51.16 (14 June 2007)
* connector-odbc-news-3-51-15::  Changes in MySQL Connector/ODBC 3.51.15 (07 May 2007)
* connector-odbc-news-3-51-14::  Changes in MySQL Connector/ODBC 3.51.14 (08 March 2007)
* connector-odbc-news-3-51-13::  Changes in MySQL Connector/ODBC 3.51.13 (Never released)
* connector-odbc-news-3-51-12::  Changes in MySQL Connector/ODBC 3.51.12 (11 February 2005)
* connector-odbc-news-3-51-11::  Changes in MySQL Connector/ODBC 3.51.11 (28 January 2005)


File: manual.info,  Node: connector-odbc-news-3-51-29,  Next: connector-odbc-news-3-51-28,  Prev: connector-odbc-news-3-51-x,  Up: connector-odbc-news-3-51-x

D.3.3.1 Changes in MySQL Connector/ODBC 3.51.29 (04 October 2011)
.................................................................

*Pluggable Authentication Notes*
   * The binaries for this distribution of Connector/ODBC can now
     connect to MySQL server accounts that use the PAM or Windows
     Native Authentication Plugins for authentication. See The PAM
     Authentication Plugin
     (http://dev.mysql.com/doc/refman/5.5/en/pam-authentication-plugin.html),
     and The Windows Native Authentication Plugin
     (http://dev.mysql.com/doc/refman/5.5/en/windows-authentication-plugin.html).
     These capabilities result from linking the Connector/ODBC binaries
     against the MySQL 5.5.16 `libmysql' rather than the MySQL 5.1
     `libmysql' used previously. The newer `libmysql' includes the
     client-side support needed for the server-side PAM and Windows
     authentication plugins.

*Bugs Fixed*

   * Some catalog functions (such as `SQLColumns()', `SQLStatistics()',
     and `SQLPrimaryKeys()') would only return one row, when called
     after pre-execution failed.  (Bug #12824839)

   * An off-by-one error, where `sqlwcharchr' might read one `SQLWCHAR'
     after the end of a string.  (Bug #61586)

   * `SQLExecute' would return `SQL_SUCCESS_WITH_INFO' instead of
     `SQL_ERROR', when column parameter binding was enabled.  (Bug
     #59772)

   * The Connector/ODBC driver did not call *Note `mysql_thread_end()':
     mysql-thread-end. when a thread ended, which caused error messages
     like: `Error in my_thread_global_end(): 1 threads didn't exit'.
     (Bug #57727)

   * MS Access fields with `VARCHAR NOT NULL' columns could not be
     altered.  (Bug #31067)


File: manual.info,  Node: connector-odbc-news-3-51-28,  Next: connector-odbc-news-3-51-27,  Prev: connector-odbc-news-3-51-29,  Up: connector-odbc-news-3-51-x

D.3.3.2 Changes in MySQL Connector/ODBC 3.51.28 (09 February 2011)
..................................................................

*Bugs Fixed*

   * `SQLColAttribute(...SQL_DESC_CASE_SENSITIVE...)' returned
     `SQL_FALSE' for binary types and `SQL_TRUE' for the rest. It
     should have returned `SQL_TRUE' for binary types, and `SQL_FALSE'
     for the rest.  (Bug #54212)

   * `SQLColAttribute' for `SQL_DESC_OCTET_LENGTH' returned length
     including terminating null byte. It should not have included the
     null byte.  (Bug #54206)

   * If `NO_BACKSLASH_ESCAPES' mode was used on a server, escaping
     binary data led to server query parsing errors.  (Bug #49029)

   * Inserting a new record using `SQLSetPos' did not correspond to the
     database name specified in the `SELECT' statement when querying
     tables from databases other than the current one.

     `SQLSetPos' attempted to do the `INSERT' in the current database,
     but finished with a `SQL_ERROR' result and `Table does not exist'
     message from MySQL Server.  (Bug #41946)

   * When using MySQL Connector/ODBC to fetch data, if a
     `net_write_timeout' condition occurred, the operation returned the
     standard "end of data" status, rather than an error.  (Bug #39878)

   * No result record was returned for `SQLGetTypeInfo' for the
     `TIMESTAMP' data type. An application would receive the result
     `return code 100 (SQL_NO_DATA_FOUND)'.  (Bug #30626)

   * Microsoft Access was not able to read `BIGINT' values properly
     from a table with just two columns of type `BIGINT' and `VARCHAR'.
     `#DELETE' appeared instead of the correct values.  (Bug #17679)


File: manual.info,  Node: connector-odbc-news-3-51-27,  Next: connector-odbc-news-3-51-26,  Prev: connector-odbc-news-3-51-28,  Up: connector-odbc-news-3-51-x

D.3.3.3 Changes in MySQL Connector/ODBC 3.51.27 (20 November 2008)
..................................................................

*Bugs Fixed*

   * The client program hung when the network connection to the server
     was interrupted.  (Bug #40407)

   * The connection string option `Enable Auto-reconnect' did not work.
     When the connection failed, it could not be restored, and the
     errors generated were the same as if the option had not been
     selected.  (Bug #37179)

   * It was not possible to use MySQL Connector/ODBC to connect to a
     server using SSL. The following error was generated:

          Runtime error '-2147467259 (80004005)':

          [MySQL][ODBC 3.51 Driver]SSL connection error.

     (Bug #29955)


File: manual.info,  Node: connector-odbc-news-3-51-26,  Next: connector-odbc-news-3-51-25,  Prev: connector-odbc-news-3-51-27,  Up: connector-odbc-news-3-51-x

D.3.3.4 Changes in MySQL Connector/ODBC 3.51.26 (07 July 2008)
..............................................................

*Functionality Added or Changed*

   * There is a new connection option, `FLAG_NO_BINARY_RESULT'. When
     set this option disables charset 63 for columns with an empty
     `org_table'.  (Bug #29402)

*Bugs Fixed*

   * When an ADOConnection is created and attempts to open a schema with
     ADOConnection.OpenSchema an access violation occurs in
     `myodbc3.dll'.  (Bug #30770)

   * When *Note `SHOW CREATE TABLE': show-create-table. was invoked and
     then the field values read, the result was truncated and unusable
     if the table had many rows and indexes.  (Bug #24131)


File: manual.info,  Node: connector-odbc-news-3-51-25,  Next: connector-odbc-news-3-51-24,  Prev: connector-odbc-news-3-51-26,  Up: connector-odbc-news-3-51-x

D.3.3.5 Changes in MySQL Connector/ODBC 3.51.25 (11 April 2008)
...............................................................

*Bugs Fixed*

   * The `SQLColAttribute()' function returned `SQL_TRUE' when querying
     the `SQL_DESC_FIXED_PREC_SCALE (SQL_COLUMN_MONEY)' attribute of a
     *Note `DECIMAL': numeric-types. column.  Previously, the correct
     value of `SQL_FALSE' was returned; this is now again the case.
     (Bug #35581)

   * The driver crashes ODBC Administrator on attempting to add a new
     DSN.  (Bug #32057)

   * When accessing column data, `FLAG_COLUMN_SIZE_S32' did not limit
     the octet length or display size reported for fields, causing
     problems with Microsoft Visual FoxPro.

     The list of ODBC functions that could have caused failures in
     Microsoft software when retrieving the length of *Note `LONGBLOB':
     blob. or *Note `LONGTEXT': blob. columns includes:

        * `SQLColumns'

        * `SQLColAttribute'

        * `SQLColAttributes'

        * `SQLDescribeCol'

        * `SQLSpecialColumns' (theoretically can have the same problem)

     (Bug #12805, Bug #30890)


File: manual.info,  Node: connector-odbc-news-3-51-24,  Next: connector-odbc-news-3-51-23,  Prev: connector-odbc-news-3-51-25,  Up: connector-odbc-news-3-51-x

D.3.3.6 Changes in MySQL Connector/ODBC 3.51.24 (14 March 2008)
...............................................................

*Bugs Fixed*

   * *Security Enhancement*: Accessing a parameter with the type of
     `SQL_C_CHAR', but with a numeric type and a length of zero, the
     parameter marker would get stripped from the query. In addition,
     an SQL injection was possible if the parameter value had a nonzero
     length and was not numeric, the text would be inserted verbatim.
     (Bug #34575)

   * *Important Change*: In previous versions, the SSL certificate
     would automatically be verified when used as part of the MySQL
     Connector/ODBC connection. The default mode is now to ignore the
     verificate of certificates. To enforce verification of the SSL
     certificate during connection, use the `SSLVERIFY' DSN parameter,
     setting the value to 1.  (Bug #29955, Bug #34648)

   * When using ADO, the count of parameters in a query would always
     return zero.  (Bug #33298)

   * Using tables with a single quote or other nonstandard characters
     in the table or column names through ODBC would fail.  (Bug #32989)

   * When using Crystal Reports, table and column names would be
     truncated to 21 characters, and truncated columns in tables where
     the truncated name was the duplicated would lead to only a single
     column being displayed.  (Bug #32864)

   * `SQLExtendedFetch()' and `SQLFetchScroll()' ignored the rowset
     size if the `Don't cache result' DSN option was set.  (Bug #32420)

   * When using the ODBC `SQL_TXN_READ_COMMITTED' option, 'dirty'
     records would be read from tables as if the option had not been
     applied.  (Bug #31959)

   * When creating a System DSN using the ODBC Administrator on Mac OS
     X, a User DSN would be created instead. The root cause is a
     problem with the iODBC driver manager used on Mac OS X. The fix
     works around this issue.

     *Note*:

     ODBC Administrator may still be unable to register a System DSN
     unless the `/Library/ODBC/odbc.ini' file has the correct
     permissions. You should ensure that the file is writable by the
     `admin' group.

     (Bug #31495)

   * Calling `SQLFetch' or `SQLFetchScroll' would return negative data
     lengths when using `SQL_C_WCHAR'.  (Bug #31220)

   * `SQLSetParam()' caused memory allocation errors due to driver
     manager's mapping of deprecated functions (buffer length -1).
     (Bug #29871)

   * Static cursor was unable to be used through ADO when dynamic
     cursors were enabled.  (Bug #27351)

   * Using `connection.Execute' to create a record set based on a table
     without declaring the cmd option as `adCmdTable' will fail when
     communicating with versions of MySQL 5.0.37 and higher. The issue
     is related to the way that `SQLSTATE' is returned when ADO tries
     to confirm the existence of the target object.  (Bug #27158)

   * Updating a `RecordSet' when the query involves a *Note `BLOB':
     blob. field would fail.  (Bug #19065)

   * With some connections to MySQL databases using MySQL
     Connector/ODBC, the connection would mistakenly report 'user
     cancelled' for accesses to the database information.  (Bug #16653)


File: manual.info,  Node: connector-odbc-news-3-51-23,  Next: connector-odbc-news-3-51-22,  Prev: connector-odbc-news-3-51-24,  Up: connector-odbc-news-3-51-x

D.3.3.7 Changes in MySQL Connector/ODBC 3.51.23 (09 January 2008)
.................................................................

*Platform-Specific Notes*

   * The HP-UX 11.23 IA64 binary package does not include the GUI bits
     because of problems building Qt on that platform.

   * There is no binary package for Mac OS X on 64-bit PowerPC because
     Apple does not currently provide a 64-bit PowerPC version of iODBC.

   * There are no installer packages for Microsoft Windows x64 Edition.

*Bugs Fixed*

   * MySQL Connector/ODBC would incorrectly return `SQL_SUCCESS' when
     checking for distributed transaction support.  (Bug #32727)

   * When using unixODBC or directly linked applications where the
     thread level is set to less than 3 (within `odbcinst.ini'), a
     thread synchronization issue would lead to an application crash.
     This was because `SQLAllocStmt()' and `SQLFreeStmt()' did not
     synchronize access to the list of statements associated with a
     connection.  (Bug #32587)

   * Cleaning up environment handles in multithread environments could
     result in a five (or more) second delay.  (Bug #32366)

   * Renaming an existing DSN entry would create a new entry with the
     new name without deleting the old entry.  (Bug #31165)

   * Setting the default database using the `DefaultDatabase' property
     of an ADO `Connection' object would fail with the error `Provider
     does not support this property'. The `SQLGetInfo()' returned the
     wrong value for `SQL_DATABASE_NAME' when no database was selected.
     (Bug #3780)


File: manual.info,  Node: connector-odbc-news-3-51-22,  Next: connector-odbc-news-3-51-21,  Prev: connector-odbc-news-3-51-23,  Up: connector-odbc-news-3-51-x

D.3.3.8 Changes in MySQL Connector/ODBC 3.51.22 (13 November 2007)
..................................................................

*Functionality Added or Changed*

   * The workaround for this bug was removed due to the fixes in MySQL
     Server 5.0.48 and 5.1.21.

     This regression was introduced by Bug #10491.

*Bugs Fixed*

   * The `English' locale would be used when formatting floating point
     values. The `C' locale is now used for these values.  (Bug #32294)

   * When accessing information about supported operations, the driver
     would return incorrect information about the support for *Note
     `UNION': union.  (Bug #32253)

   * Unsigned integer values greater than the maximum value of a signed
     integer would be handled incorrectly.  (Bug #32171)

   * The wrong result was returned by `SQLGetData()' when the data was
     an empty string and a zero-sized buffer was specified.  (Bug
     #30958)

   * Added the `FLAG_COLUMN_SIZE_S32' option to limit the reported
     column size to a signed 32-bit integer. This option is
     automatically enabled for ADO applications to provide a work
     around for a bug in ADO.  (Bug #13776)


File: manual.info,  Node: connector-odbc-news-3-51-21,  Next: connector-odbc-news-3-51-20,  Prev: connector-odbc-news-3-51-22,  Up: connector-odbc-news-3-51-x

D.3.3.9 Changes in MySQL Connector/ODBC 3.51.21 (08 October 2007)
.................................................................

*Bugs Fixed*

   * When using a rowset/cursor and add a new row with a number of
     fields, subsequent rows with fewer fields will include the
     original fields from the previous row in the final *Note `INSERT':
     insert. statement.  (Bug #31246)

   * Uninitiated memory could be used when C/ODBC internally calls
     `SQLGetFunctions()'.  (Bug #31055)

   * The wrong `SQL_DESC_LITERAL_PREFIX' would be returned for
     date/time types.  (Bug #31009)

   * The wrong `COLUMN_SIZE' would be returned by `SQLGetTypeInfo' for
     the TIME columns (`SQL_TYPE_TIME').  (Bug #30939)

   * Clicking outside the character set selection box when configuring
     a new DSN could cause the wrong character set to be selected.
     (Bug #30568)

   * Not specifying a user in the DSN dialog would raise a warning even
     though the parameter is optional.  (Bug #30499)

   * `SQLSetParam()' caused memory allocation errors due to driver
     manager's mapping of deprecated functions (buffer length -1).
     (Bug #29871)

   * When using ADO, a column marked as `AUTO_INCREMENT' could
     incorrectly report that the column permitted `NULL' values. This
     was dur to an issue with `NULLABLE' and `IS_NULLABLE' return
     values from the call to `SQLColumns()'.  (Bug #26108)

   * MySQL Connector/ODBC would return the wrong the error code when
     the server disconnects the active connection because the configured
     `wait_timeout' has expired.  Previously it would return `HY000'.
     MySQL Connector/ODBC now correctly returns an `SQLSTATE' of
     `08S01'.  (Bug #3456)


File: manual.info,  Node: connector-odbc-news-3-51-20,  Next: connector-odbc-news-3-51-19,  Prev: connector-odbc-news-3-51-21,  Up: connector-odbc-news-3-51-x

D.3.3.10 Changes in MySQL Connector/ODBC 3.51.20 (10 September 2007)
....................................................................

*Bugs Fixed*

   * Using `FLAG_NO_PROMPT' doesn't suppress the dialogs normally
     handled by `SQLDriverConnect'.  (Bug #30840)

   * The specified length of the user name and authentication
     parameters to `SQLConnect()' were not being honored.  (Bug #30774)

   * The wrong column size was returned for binary data.  (Bug #30547)

   * `SQLGetData()' will now always return `SQL_NO_DATA_FOUND' on
     second call when no data left, even if requested size is 0.  (Bug
     #30520)

   * `SQLGetConnectAttr()' did not reflect the connection state
     correctly.  (Bug #14639)

   * Removed check box in setup dialog for `FLAG_FIELD_LENGTH'
     (identified as `Don't Optimize Column Width' within the GUI
     dialog), which was removed from the driver in 3.51.18.


File: manual.info,  Node: connector-odbc-news-3-51-19,  Next: connector-odbc-news-3-51-18,  Prev: connector-odbc-news-3-51-20,  Up: connector-odbc-news-3-51-x

D.3.3.11 Changes in MySQL Connector/ODBC 3.51.19 (10 August 2007)
.................................................................

Connector/ODBC 3.51.19 fixes a specific issue with the 3.51.18 release.
For a list of changes in the 3.51.18 release, see *Note
connector-odbc-news-3-51-18::.

*Functionality Added or Changed*

   * Because of Bug #10491 in the server, character string results were
     sometimes incorrectly identified as `SQL_VARBINARY'. Until this
     server bug is corrected, the driver will identify all
     variable-length strings as `SQL_VARCHAR'.


File: manual.info,  Node: connector-odbc-news-3-51-18,  Next: connector-odbc-news-3-51-17,  Prev: connector-odbc-news-3-51-19,  Up: connector-odbc-news-3-51-x

D.3.3.12 Changes in MySQL Connector/ODBC 3.51.18 (08 August 2007)
.................................................................

*Platform-Specific Notes*

   * The HP-UX 11.23 IA64 binary package does not include the GUI bits
     because of problems building Qt on that platform.

   * There is no binary package for Mac OS X on 64-bit PowerPC because
     Apple does not currently provide a 64-bit PowerPC version of iODBC.

   * Binary packages for Sun Solaris are now available as `PKG'
     packages.

   * Binary packages as disk images with installers are now available
     for Mac OS X.

   * A binary package without an installer is available for Microsoft
     Windows x64 Edition. There are no installer packages for Microsoft
     Windows x64 Edition.

*Functionality Added or Changed*

   * *Incompatible Change*: The `FLAG_DEBUG' option was removed.

   * When connecting to a specific database when using a DSN, the
     system tables from the `mysql' database are no longer also
     available. Previously, tables from the mysql database (catalog)
     were listed as `SYSTEM TABLES' by `SQLTables()' even when a
     different catalog was being queried.  (Bug #28662)

   * Installed for Mac OS X has been re-instated. The installer
     registers the driver at a system (not user) level and makes it
     possible to create both user and system DSNs using the MySQL
     Connector/ODBC driver. The installer also fixes the situation
     where the necessary drivers would bge installed local to the user,
     not globally.  (Bug #15326, Bug #10444)

   * MySQL Connector/ODBC now supports batched statements. To enable
     cached statement support, you must switch enable the batched
     statement option (`FLAG_MULTI_STATEMENTS', 67108864, or `Allow
     multiple statements' within a GUI configuration). Be aware that
     batched statements create an increased chance of SQL injection
     attacks and you must ensure that your application protects against
     this scenario.  (Bug #7445)

   * The `SQL_ATTR_ROW_BIND_OFFSET_PTR' is now supported for row bind
     offsets.  (Bug #6741)

   * The `TRACE' and `TRACEFILE' DSN options have been removed. Use the
     ODBC driver manager trace options instead.

*Bugs Fixed*

   * When using a table with multiple *Note `TIMESTAMP': datetime.
     columns, the final *Note `TIMESTAMP': datetime. column within the
     table definition would not be updateable. Note that there is still
     a limitation in MySQL server regarding multiple *Note `TIMESTAMP':
     datetime. columns.  (Bug #30081) See also Bug #9927.

   * Fixed an issue where the `myodbc3i' would update the user ODBC
     configuration file (`~/Library/ODBC/odbcinst.ini') instead of the
     system `/Library/ODBC/odbcinst.ini'. This was caused because
     `myodbc3i' was not honoring the `s' and `u' modifiers for the `-d'
     command-line option.  (Bug #29964)

   * Getting table metadata (through the `SQLColumns()' would fail,
     returning a bad table definition to calling applications.  (Bug
     #29888)

   * *Note `DATETIME': datetime. column types would return `FALSE' in
     place of `SQL_SUCCESS' when requesting the column type information.
     (Bug #28657)

   * The `SQL_COLUMN_TYPE', `SQL_COLUMN_DISPLAY' and
     `SQL_COLUMN_PRECISION' values would be returned incorrectly by
     `SQLColumns()', `SQLDescribeCol()' and `SQLColAttribute()' when
     accessing character columns, especially those generated through
     `concat()'. The lengths returned should now conform to the ODBC
     specification. The `FLAG_FIELD_LENGTH' option no longer has any
     affect on the results returned.  (Bug #27862)

   * Obtaining the length of a column when using a character set for
     the connection of `utf8' would result in the length being returned
     incorrectly.  (Bug #19345)

   * The `SQLColumns()' function could return incorrect information
     about *Note `TIMESTAMP': datetime. columns, indicating that the
     field was not nullable.  (Bug #14414)

   * The `SQLColumns()' function could return incorrect information
     about `AUTO_INCREMENT' columns, indicating that the field was not
     nullable.  (Bug #14407)

   * A binary package without an installer is available for Microsoft
     Windows x64 Edition. There are no installer packages for Microsoft
     Windows x64 Edition.

   * There is no binary package for Mac OS X on 64-bit PowerPC because
     Apple does not currently provide a 64-bit PowerPC version of iODBC.

   * `BIT(n)' columns are now treated as `SQL_BIT' data where `n = 1'
     and binary data where `n > 1'.

   * The wrong value from `SQL_DESC_LITERAL_SUFFIX' was returned for
     binary fields.

   * The `SQL_DATETIME_SUB' column in SQLColumns() was not correctly
     set for date and time types.

   * The value for `SQL_DESC_FIXED_PREC_SCALE' was not returned
     correctly for values in MySQL 5.0 and later.

   * The wrong value for `SQL_DESC_TYPE' was returned for date and time
     types.

   * `SQLConnect()' and `SQLDriverConnect()' were rewritten to
     eliminate duplicate code and ensure all options were supported
     using both connection methods.  `SQLDriverConnect()' now only
     requires the setup library to be present when the call requires it.

   * The HP-UX 11.23 IA64 binary package does not include the GUI bits
     because of problems building Qt on that platform.

   * Binary packages as disk images with installers are now available
     for Mac OS X.

   * Binary packages for Sun Solaris are now available as `PKG'
     packages.

   * The wrong value for `DECIMAL_DIGITS' in `SQLColumns()' was
     reported for *Note `FLOAT': numeric-types. and *Note `DOUBLE':
     numeric-types. fields, as well as the wrong value for the scale
     parameter to `SQLDescribeCol()', and the `SQL_DESC_SCALE'
     attribute from `SQLColAttribute()'.

   * The `SQL_DATA_TYPE' column in `SQLColumns()' results did not
     report the correct value for date and time types.


File: manual.info,  Node: connector-odbc-news-3-51-17,  Next: connector-odbc-news-3-51-16,  Prev: connector-odbc-news-3-51-18,  Up: connector-odbc-news-3-51-x

D.3.3.13 Changes in MySQL Connector/ODBC 3.51.17 (14 July 2007)
...............................................................

*Platform-Specific Notes*

   * The HP-UX 11.23 IA64 binary package does not include the GUI bits
     because of problems building Qt on that platform.

   * There is no binary package for Mac OS X on 64-bit PowerPC because
     Apple does not currently provide a 64-bit PowerPC version of iODBC.

   * Binary packages for Sun Solaris are now available as `PKG'
     packages.

   * Binary packages as disk images with installers are now available
     for Mac OS X.

   * A binary package without an installer is available for Microsoft
     Windows x64 Edition. There are no installer packages for Microsoft
     Windows x64 Edition.

*Functionality Added or Changed*

   * It is now possible to specify a different character set as part of
     the DSN or connection string. This must be used instead of the
     `SET NAMES' statement. You can also configure the character set
     value from the GUI configuration.  (Bug #9498, Bug #6667)

   * Fixed calling convention ptr and wrong free in `myodbc3i', and
     fixed the null terminating (was only one, not two) when writing
     DSN to string.

   * Dis-allow NULL ptr for null indicator when calling SQLGetData() if
     value is null. Now returns SQL_ERROR w/state 22002.

   * The setup library has been split into its own RPM package, to
     enable installing the driver itself with no GUI dependencies.

*Bugs Fixed*

   * `myodbc3i' did not correctly format driver info, which could cause
     the installation to fail.  (Bug #29709)

   * MySQL Connector/ODBC crashed with Crystal Reports due to a
     rproblem with `SQLProcedures()'.  (Bug #28316)

   * Fixed a problem where the GUI would crash when configuring or
     removing a System or User DSN.  (Bug #27315)

   * Fixed error handling of out-of-memory and bad connections in
     catalog functions. This might raise errors in code paths that had
     ignored them in the past.  (Bug #26934)

   * For a stored procedure that returns multiple result sets, MySQL
     Connector/ODBC returned only the first result set.  (Bug #16817)

   * Calling `SQLGetDiagField' with `RecNumber 0, DiagIdentifier NOT 0'
     returned `SQL_ERROR', preventing access to diagnostic header
     fields.  (Bug #16224)

   * Added a new DSN option (`FLAG_ZERO_DATE_TO_MIN') to retrieve
     `XXXX-00-00' dates as the minimum permitted ODBC date
     (`XXXX-01-01'). Added another option (`FLAG_MIN_DATE_TO_ZERO') to
     mirror this but for bound parameters. `FLAG_MIN_DATE_TO_ZERO' only
     changes `0000-01-01' to `0000-00-00'.  (Bug #13766)

   * If there was more than one unique key on a table, the correct
     fields were not used in handling `SQLSetPos()'.  (Bug #10563)

   * When inserting a large *Note `BLOB': blob.  field, MySQL
     Connector/ODBC would crash due to a memory allocation error.  (Bug
     #10562)

   * The driver was using `mysql_odbc_escape_string()', which does not
     handle the `NO_BACKSLASH_ESCAPES' SQL mode.  Now it uses *Note
     `mysql_real_escape_string()': mysql-real-escape-string, which does.
     (Bug #9498)

   * `SQLColumns()' did not handle many of its parameters correctly,
     which could lead to incorrect results. The table name argument was
     not handled as a pattern value, and most arguments were not
     escaped correctly when they contained nonalphanumeric characters.
     (Bug #8860)

   * There are no binary packages for Microsoft Windows x64 Edition.

   * There is no binary package for Mac OS X on 64-bit PowerPC because
     Apple does not currently provide a 64-bit PowerPC version of iODBC.

   * Correctly return error if `SQLBindCol' is called with an invalid
     column.

   * Fixed possible crash if `SQLBindCol()' was not called before
     `SQLSetPos()'.

   * The Mac OS X binary packages are only provided as tarballs, there
     is no installer.

   * The binary packages for Sun Solaris are only provided as tarballs,
     not the PKG format.

   * The HP-UX 11.23 IA64 binary package does not include the GUI bits
     because of problems building Qt on that platform.


File: manual.info,  Node: connector-odbc-news-3-51-16,  Next: connector-odbc-news-3-51-15,  Prev: connector-odbc-news-3-51-17,  Up: connector-odbc-news-3-51-x

D.3.3.14 Changes in MySQL Connector/ODBC 3.51.16 (14 June 2007)
...............................................................

*Functionality Added or Changed*

   * MySQL Connector/ODBC now supports using SSL for communication.
     This is not yet exposed in the setup GUI, but must be enabled
     through configuration files or the DSN.  (Bug #12918)

*Bugs Fixed*

   * Calls to SQLNativeSql() could cause stack corruption due to an
     incorrect pointer cast.  (Bug #28758)

   * Using cursors on results sets with multi-column keys could select
     the wrong value.  (Bug #28255)

   * `SQLForeignKeys' does not escape `_' and `%' in the table name
     arguments.  (Bug #27723)

   * When using stored procedures, making a *Note `SELECT': select. or
     second stored procedure call after an initial stored procedure
     call, the second statement will fail.  (Bug #27544)

   * SQLTables() did not distinguish tables from views.  (Bug #23031)

   * Return values from `SQLTables()' may be truncated.  (Bug #22797)

   * Data in *Note `TEXT': blob. columns would fail to be read
     correctly.  (Bug #16917)

   * Specifying strings as parameters using the `adBSTR' or `adVarWChar'
     types, (`SQL_WVARCHAR' and `SQL_WLONGVARCHAR') would be incorrectly
     quoted.  (Bug #16235)

   * SQL_WVARCHAR and SQL_WLONGVARCHAR parameters were not properly
     quoted and escaped.  (Bug #16235)

   * Using `BETWEEN' with date values, the wrong results could be
     returned.  (Bug #15773)

   * When using the `Don't Cache Results' (option value `1048576') with
     Microsoft Access, the connection will fail using DAO/VisualBasic.
     (Bug #4657)


File: manual.info,  Node: connector-odbc-news-3-51-15,  Next: connector-odbc-news-3-51-14,  Prev: connector-odbc-news-3-51-16,  Up: connector-odbc-news-3-51-x

D.3.3.15 Changes in MySQL Connector/ODBC 3.51.15 (07 May 2007)
..............................................................

*Bugs Fixed*

   * MySQL Connector/ODBC would incorrectly claim to support
     `SQLProcedureColumns' (by returning true when queried about
     `SQLPROCEDURECOLUMNS' with `SQLGetFunctions'), but this
     functionality is not supported.  (Bug #27591)

   * An incorrect transaction isolation level may not be returned when
     accessing the connection attributes.  (Bug #27589)

   * Adding a new DSN with the `myodbc3i' utility under AIX would fail.
     (Bug #27220)

   * When inserting data using bulk statements (through
     `SQLBulkOperations'), the indicators for all rows within the
     insert would not updated correctly.  (Bug #24306)

   * Using `SQLProcedures' does not return the database name within the
     returned resultset.  (Bug #23033)

   * The `SQLTransact()' function did not support an empty connection
     handle.  (Bug #21588)

   * Using `SQLDriverConnect' instead of `SQLConnect' could cause later
     operations to fail.  (Bug #7912)

   * When using blobs and parameter replacement in a statement with
     `WHERE CURSOR OF', the SQL is truncated.  (Bug #5853)

   * MySQL Connector/ODBC would return too many foreign key results
     when accessing tables with similar names.  (Bug #4518)


File: manual.info,  Node: connector-odbc-news-3-51-14,  Next: connector-odbc-news-3-51-13,  Prev: connector-odbc-news-3-51-15,  Up: connector-odbc-news-3-51-x

D.3.3.16 Changes in MySQL Connector/ODBC 3.51.14 (08 March 2007)
................................................................

*Functionality Added or Changed*

   * Use of `SQL_ATTR_CONNECTION_TIMEOUT' on the server has now been
     disabled. If you attempt to set this attribute on your connection
     the `SQL_SUCCESS_WITH_INFO' will be returned, with an error
     number/string of `HYC00: Optional feature not supported'.  (Bug
     #19823)

   * Added auto is null option to MySQL Connector/ODBC option
     parameters.  (Bug #10910)

   * Added auto-reconnect option to MySQL Connector/ODBC option
     parameters.

   * Added support for the `HENV' handlers in `SQLEndTran()'.

*Bugs Fixed*

   * On 64-bit systems, some types would be incorrectly returned.  (Bug
     #26024)

   * When retrieving *Note `TIME': time. columns, C/ODBC would
     incorrectly interpret the type of the string and could interpret
     it as a *Note `DATE': datetime. type instead.  (Bug #25846)

   * MySQL Connector/ODBC may insert the wrong parameter values when
     using prepared statements under 64-bit Linux.  (Bug #22446)

   * Using MySQL Connector/ODBC, with `SQLBindCol' and binding the
     length to the return value from `SQL_LEN_DATA_AT_EXEC' fails with
     a memory allocation error.  (Bug #20547)

   * Using `DataAdapter', MySQL Connector/ODBC may continually consume
     memory when reading the same records within a loop (Windows Server
     2003 SP1/SP2 only).  (Bug #20459)

   * When retrieving data from columns that have been compressed using
     `COMPRESS()', the retrieved data would be truncated to 8KB.  (Bug
     #20208)

   * The ODBC driver name and version number were incorrectly reported
     by the driver.  (Bug #19740)

   * A string format exception would be raised when using iODBC, MySQL
     Connector/ODBC and the embedded MySQL server.  (Bug #16535)

   * The `SQLDriverConnect()' ODBC method did not work with recent
     MySQL Connector/ODBC releases.  (Bug #12393)


File: manual.info,  Node: connector-odbc-news-3-51-13,  Next: connector-odbc-news-3-51-12,  Prev: connector-odbc-news-3-51-14,  Up: connector-odbc-news-3-51-x

D.3.3.17 Changes in MySQL Connector/ODBC 3.51.13 (Never released)
.................................................................

Connector/ODBC 3.51.13 was an internal implementation and testing
release.

This section has no changelog entries.


File: manual.info,  Node: connector-odbc-news-3-51-12,  Next: connector-odbc-news-3-51-11,  Prev: connector-odbc-news-3-51-13,  Up: connector-odbc-news-3-51-x

D.3.3.18 Changes in MySQL Connector/ODBC 3.51.12 (11 February 2005)
...................................................................

*Functionality Added or Changed*

   * N/A

*Bugs Fixed*

   * Using stored procedures with ADO, where the `CommandType' has been
     set correctly to `adCmdStoredProc', calls to stored procedures
     would fail.  (Bug #15635)

   * File DSNs could not be saved.  (Bug #12019)

   * `SQLColumns()' returned no information for tables that had a
     column named using a reserved word.  (Bug #9539)


File: manual.info,  Node: connector-odbc-news-3-51-11,  Prev: connector-odbc-news-3-51-12,  Up: connector-odbc-news-3-51-x

D.3.3.19 Changes in MySQL Connector/ODBC 3.51.11 (28 January 2005)
..................................................................

*Bugs Fixed*

   * `mysql_list_dbcolumns()' and `insert_fields()' were retrieving all
     rows from a table. Fixed the queries generated by these functions
     to return no rows.  (Bug #8198)

   * `SQLGetTypoInfo()' returned `tinyblob' for `SQL_VARBINARY' and
     nothing for `SQL_BINARY'. Fixed to return `varbinary' for
     `SQL_VARBINARY', `binary' for `SQL_BINARY', and `longblob' for
     `SQL_LONGVARBINARY'.  (Bug #8138)


File: manual.info,  Node: connector-net-news,  Next: vstudio-plugin-news,  Prev: connector-odbc-news,  Up: news

D.4 MySQL Connector/Net Change History
======================================

* Menu:

* connector-net-news-6-4-x::     Changes in MySQL Connector/Net Version 6.4.x
* connector-net-news-6-3-x::     Changes in MySQL Connector/Net Version 6.3.x
* connector-net-news-6-2-x::     Changes in MySQL Connector/Net Version 6.2.x
* connector-net-news-6-1-x::     Changes in MySQL Connector/Net Version 6.1.x
* connector-net-news-6-0-x::     Changes in MySQL Connector/Net Version 6.0.x
* connector-net-news-5-3-x::     Changes in MySQL Connector/Net Version 5.3.x
* connector-net-news-5-2-x::     Changes in MySQL Connector/Net Version 5.2.x
* connector-net-news-5-1-x::     Changes in MySQL Connector/Net Version 5.1.x
* connector-net-news-5-0-x::     Changes in MySQL Connector/Net Version 5.0.x
* connector-net-news-1-0-x::     Changes in MySQL Connector/Net Version 1.0.x
* connector-net-news-0-9-0::     Changes in MySQL Connector/Net Version 0.9.0 (30 August 2004)
* connector-net-news-0-76::      Changes in MySQL Connector/Net Version 0.76
* connector-net-news-0-75::      Changes in MySQL Connector/Net Version 0.75
* connector-net-news-0-74::      Changes in MySQL Connector/Net Version 0.74
* connector-net-news-0-71::      Changes in MySQL Connector/Net Version 0.71
* connector-net-news-0-70::      Changes in MySQL Connector/Net Version 0.70
* connector-net-news-0-68::      Changes in MySQL Connector/Net Version 0.68
* connector-net-news-0-65::      Changes in MySQL Connector/Net Version 0.65
* connector-net-news-0-60::      Changes in MySQL Connector/Net Version 0.60
* connector-net-news-0-50::      Changes in MySQL Connector/Net Version 0.50


File: manual.info,  Node: connector-net-news-6-4-x,  Next: connector-net-news-6-3-x,  Prev: connector-net-news,  Up: connector-net-news

D.4.1 Changes in MySQL Connector/Net Version 6.4.x
--------------------------------------------------

* Menu:

* connector-net-news-6-4-4::     Changes in MySQL Connector/Net 6.4.4 (26 September 2011)
* connector-net-news-6-4-3::     Changes in MySQL Connector/Net 6.4.3 (03 July 2011)
* connector-net-news-6-4-2::     Changes in MySQL Connector/Net 6.4.2 (29 June 2011)
* connector-net-news-6-4-1::     Changes in MySQL Connector/Net 6.4.1 (06 June 2011 Alpha)


File: manual.info,  Node: connector-net-news-6-4-4,  Next: connector-net-news-6-4-3,  Prev: connector-net-news-6-4-x,  Up: connector-net-news-6-4-x

D.4.1.1 Changes in MySQL Connector/Net 6.4.4 (26 September 2011)
................................................................

This release fixes bugs since 6.4.3.

*Functionality Added or Changed*

   * Connector/Net now enables clients to connect to the server through
     accounts that use Windows native authentication. See The Windows
     Native Authentication Plugin
     (http://dev.mysql.com/doc/refman/5.5/en/windows-authentication-plugin.html).

*Bugs Fixed*

   * `MySqlDataReader.Close' was modified to use Default behavior when
     clearing remaining result sets.  (Bug #61690, Bug #12723423)

   * `MySqlScript' was modified to enable correct processing of the
     `DELIMITER' command when not followed by a new line.  (Bug #61680,
     Bug #12732279)

   * The ASP.NET membership provider was modified to create and query
     all related tables using lowercase names.  (Bug #61108, Bug
     #12702009)

   * On Model First changed column types generated in SQL scripts to
     produce more suitable `MySql' types.  (Bug #59244, Bug #12707104)


File: manual.info,  Node: connector-net-news-6-4-3,  Next: connector-net-news-6-4-2,  Prev: connector-net-news-6-4-4,  Up: connector-net-news-6-4-x

D.4.1.2 Changes in MySQL Connector/Net 6.4.3 (03 July 2011)
...........................................................

This release fixes bugs since 6.4.2.

*Bugs Fixed*

   * `SchemaDefinition-5.5.ssdl' was modified to treat `CHAR(36)'
     columns as a GUID.  (Bug #61657, Bug #12708208)

   * `SqlFragment.QuoteIdentifier' was modified to add MySQL quotes
     around identifiers.  (Bug #61635, Bug #12707285)


File: manual.info,  Node: connector-net-news-6-4-2,  Next: connector-net-news-6-4-1,  Prev: connector-net-news-6-4-3,  Up: connector-net-news-6-4-x

D.4.1.3 Changes in MySQL Connector/Net 6.4.2 (29 June 2011)
...........................................................

This release fixes bugs since 6.4.1.

*Bugs Fixed*

   * Modified `MySqlConnection.BeginTransaction' to throw a
     `NotSupportedException' for `Snapshot' isolation level.  (Bug
     #61589, Bug #12698020)

   * Modified `ProviderManifest.xml' to map `TIMESTAMP' database
     columns to the `DateTime' .NET type.  (Bug #55351, Bug #12652602)

   * Fixed Entity Framework provider `GROUP BY' clause generation by
     adding all group-by keys to the `SELECT' statement.  (Bug #46742,
     Bug #12622129)


File: manual.info,  Node: connector-net-news-6-4-1,  Prev: connector-net-news-6-4-2,  Up: connector-net-news-6-4-x

D.4.1.4 Changes in MySQL Connector/Net 6.4.1 (06 June 2011 Alpha)
.................................................................

First alpha release.

*Functionality Added or Changed*

   * Calling a stored procedure with output parameters caused a marked
     performance decrease.  (Bug #60366, Bug #12425959)

   * Changed how the procedure schema collection is retrieved. If the
     connection string contains ``use procedure bodies=true'' then a
     *Note `SELECT': select. is performed on the `mysql.proc' table
     directly, as this is up to 50 times faster than the current
     Information Schema implementation. If the connection string
     contains ``use procedure bodies=false'', then the Information
     Schema collection is queried.  (Bug #36694)


File: manual.info,  Node: connector-net-news-6-3-x,  Next: connector-net-news-6-2-x,  Prev: connector-net-news-6-4-x,  Up: connector-net-news

D.4.2 Changes in MySQL Connector/Net Version 6.3.x
--------------------------------------------------

* Menu:

* connector-net-news-6-3-9::     Changes in MySQL Connector/Net 6.3.9 (Not yet released)
* connector-net-news-6-3-8::     Changes in MySQL Connector/Net 6.3.8 (Not yet released)
* connector-net-news-6-3-7::     Changes in MySQL Connector/Net 6.3.7 (22 June 2011)
* connector-net-news-6-3-6::     Changes in MySQL Connector/Net 6.3.6 (03 January 2011)
* connector-net-news-6-3-5::     Changes in MySQL Connector/Net 6.3.5 (12 October 2010)
* connector-net-news-6-3-4::     Changes in MySQL Connector/Net 6.3.4 (01 September 2010 GA)
* connector-net-news-6-3-3::     Changes in MySQL Connector/Net 6.3.3 (27 July 2010)
* connector-net-news-6-3-2::     Changes in MySQL Connector/Net 6.3.2 (24 May 2010 beta)
* connector-net-news-6-3-1::     Changes in MySQL Connector/Net 6.3.1 (02 March 2010)
* connector-net-news-6-3-0::     Changes in MySQL Connector/Net 6.3.0 (16 February 2010 alpha)


File: manual.info,  Node: connector-net-news-6-3-9,  Next: connector-net-news-6-3-8,  Prev: connector-net-news-6-3-x,  Up: connector-net-news-6-3-x

D.4.2.1 Changes in MySQL Connector/Net 6.3.9 (Not yet released)
...............................................................

This release fixes bugs since 6.3.8.

*Bugs Fixed*

   * Connector/NET would incorrectly map decimal values to ANSI strings.
     (Bug #62246, Bug #13050570)

   * Connector/NET incorrectly maps `PrimitiveTypeKind.Byte' to
     `tinyint', instead of `utinyint'. And `PrimitiveTypeKind.SByte'
     mapping was added, to `tinyint'.  (Bug #62135, Bug #13061713)

   * On Model First changed column types generated in SQL scripts to
     produce more suitable `MySql' types.  (Bug #59244, Bug #12707104)


File: manual.info,  Node: connector-net-news-6-3-8,  Next: connector-net-news-6-3-7,  Prev: connector-net-news-6-3-9,  Up: connector-net-news-6-3-x

D.4.2.2 Changes in MySQL Connector/Net 6.3.8 (Not yet released)
...............................................................

This release fixes bugs since 6.3.7.

*Bugs Fixed*

   * The default value for `VARCHAR' and `CHAR' field types would
     contain single quotation marks.  (Bug #13442506)

   * Connector/NET experienced poor performance when adding parameters
     to the `MySQLCommand'.  (Bug #62653, Bug #13331475)

   * The Unicode quotation mark character `U+0022' was not escaped by
     the `MySQLHelper' class.  (Bug #62585, Bug #13092886)

   * Using a return parameter without a name resulted in an
     `IndexOutOfRangeException' exception.  (Bug #62416, Bug #13006969)

   * The `Mono' runtime did not support hashed passwords.  (Bug #62203,
     Bug #13041618)

   * `MySqlDataReader.Close' was modified to use Default behavior when
     clearing remaining result sets.  (Bug #61690, Bug #12723423)

   * `MySqlScript' was modified to enable correct processing of the
     `DELIMITER' command when not followed by a new line.  (Bug #61680,
     Bug #12732279)

   * `SchemaDefinition-5.5.ssdl' was modified to treat `CHAR(36)'
     columns as a GUID.  (Bug #61657, Bug #12708208)

   * `SqlFragment.QuoteIdentifier' was modified to add MySQL quotes
     around identifiers.  (Bug #61635, Bug #12707285)

   * Modified `MySqlConnection.BeginTransaction' to throw a
     `NotSupportedException' for `Snapshot' isolation level.  (Bug
     #61589, Bug #12698020)

   * The ASP.NET membership provider was modified to create and query
     all related tables using lowercase names.  (Bug #61108, Bug
     #12702009)

   * Modified `ProviderManifest.xml' to map `TIMESTAMP' database
     columns to the `DateTime' .NET type.  (Bug #55351, Bug #12652602)


File: manual.info,  Node: connector-net-news-6-3-7,  Next: connector-net-news-6-3-6,  Prev: connector-net-news-6-3-8,  Up: connector-net-news-6-3-x

D.4.2.3 Changes in MySQL Connector/Net 6.3.7 (22 June 2011)
...........................................................

This release fixes bugs since 6.3.6.

*Functionality Added or Changed*

   * Calling a stored procedure with output parameters caused a marked
     performance decrease.  (Bug #60366, Bug #12425959)

*Bugs Fixed*

   * MySQL Connector/Net 6.3.6 did not work with Visual Studio 2010.
     (Bug #60723, Bug #12394470)

   * `MysqlDataReader.GetSchemaTable' returned incorrect values and
     types.  (Bug #59989, Bug #11776346)

   * All queries other than `INSERT' were executed individually instead
     of as a batch even though batching was enabled for the connection.
     (Bug #59616, Bug #11850286)

   * MySQL Connector/Net generated an exception when executing a query
     consisting of ';', for example:

          mycmd(";",mycon)
          mycmd.executenonquery()

     The exception generated was:

          System.IndexOutOfRangeException: Index was outside the bounds of the array.
             at MySql.Data.MySqlClient.MySqlCommand.TrimSemicolons(String sql)
             at MySql.Data.MySqlClient.MySqlCommand.ExecuteReader(CommandBehavior behavior)
             at MySql.Data.MySqlClient.MySqlCommand.ExecuteReader()
             at MySql.Data.MySqlClient.MySqlCommand.ExecuteNonQuery()

     (Bug #59537, Bug #11766433)

   * Setting `Membership.ApplicationName' had no effect.  (Bug #59438,
     Bug #11770465)

   * A `NullReferenceException' was thrown on disposal of a
     `TransactionScope' object.  (Bug #59346, Bug #11766272)

   * The setup wizard failed with the error `Setup Wizard ended
     prematurely because of an error'. This was because it assumed .NET
     Framework version 4.0 was located on the C: drive, when it was
     actually located on the E: drive.  (Bug #59301)

   * Fixed Entity Framework provider `GROUP BY' clause generation by
     adding all group-by keys to the `SELECT' statement.  (Bug #46742,
     Bug #12622129)


File: manual.info,  Node: connector-net-news-6-3-6,  Next: connector-net-news-6-3-5,  Prev: connector-net-news-6-3-7,  Up: connector-net-news-6-3-x

D.4.2.4 Changes in MySQL Connector/Net 6.3.6 (03 January 2011)
..............................................................

This release fixes bugs since 6.3.5.

*Functionality Added or Changed*

   * Changed how the procedure schema collection is retrieved. If the
     connection string contains ``use procedure bodies=true'' then a
     *Note `SELECT': select. is performed on the `mysql.proc' table
     directly, as this is up to 50 times faster than the current
     Information Schema implementation. If the connection string
     contains ``use procedure bodies=false'', then the Information
     Schema collection is queried.  (Bug #36694)

*Bugs Fixed*

   * `MembershipProvider' did not generate hashes correctly if the
     algorithm was keyed. The Key of the algorithm should have been set
     if the `HashAlgorithm' was `KeyedHashAlgorithm'.  (Bug #58906)

   * Code introduced to fix bug #54863 proved problematic on .NET
     version 3.5 and above.  (Bug #58853)

   * The `MySqlTokenizer' contained unnecessary `Substring' and `Trim'
     calls:

          string token = sql.Substring(startIndex, stopIndex - startIndex).Trim();

     The variable `token' was not used anywhere in the code.  (Bug
     #58757)

   * `MySqlCommand.ExecuteReader(CommandBehavior)' threw a
     `NullReferenceException' when being called with
     `CommandBehavior.CloseConnection', if the SQL statement contained
     a syntax error, or contained invalid data such as an invalid
     column name.  (Bug #58652)

   * `ReadFieldLength()' returned incorrect value for `BIGINT'
     autoincrement columns.  (Bug #58373)

   * When attempting to create an ADO.NET Entity Data Model, MySQL
     connections were not available.  (Bug #58278)

   * MySQL Connector/Net did not support the `utf8mb4' character set.
     When attempting to connect to `utf8mb4' tables or columns, an
     exception `KeyNotFoundException' was generated.  (Bug #58244)

   * Installation of MySQL Connector/Net 6.3.5 failed. The error
     reported was:

          MySQL Connector Net 6.3.5 Setup Wizard ended
          prematurely because of an error. Your system has not been modified.

     (Bug #57654)

   * When the tracing driver was used and an SQL statement was longer
     than 300 characters, an ArgumentOutOfRangeExcpetion occurred if
     the statement also contained a quoted character, and the 300th
     character was in the middle of a quoted token.  (Bug #57641)

   * Calling the `Read()' method on a `DataReader' obtained from
     `MySqlHelper.ExecuteReader' generated the following exception:

          Unhandled Exception: MySql.Data.MySqlClient.MySqlException: Invalid attempt to R
          ead when reader is closed.
             at MySql.Data.MySqlClient.MySqlDataReader.Read()
             at MySqlTest.MainClass.Main(String[] args)

     (Bug #57501)

   * Default values returned for text columns were not quoted. This
     meant that the `COLUMN_DEFAULT' field of the `GetSchema' columns
     collection did not return a valid SQL expression.  (Bug #56509)

   * When using MySQL Connector/Net on Mono 2.8 using .NET 4.0,
     attempting to connect to a MySQL database generated the following
     exception:

          Unhandled Exception: System.MissingMethodException: Method not found:
           'System.Data.Common.DbConnection.EnlistTransaction'.
            at (wrapper remoting-invoke-with-check)
           MySql.Data.MySqlClient.MySqlConnection:Open ()

     (Bug #56509)

   * MySQL Connector/Net for .NET/Mono attempted to dynamically load
     the assembly `Mono.Posix.dll' when a Unix socket was used to
     connect to the server. This failed and the connector was not able
     to use a Unix socket unless the `Mono.Posix.dll' assembly was
     previously loaded by the program.  (Bug #56410)

   * The ADO.NET Entity Data Model could not add stored procedures from
     MySQL Server 5.0.45 but worked fine using MySQL Server 5.1.  (Bug
     #55349)

   * In the ADO.NET Entity Data Model Wizard, the time to update a
     model scaled abnormally as the number of entities increased.  (Bug
     #48791, Bug #12596237)


File: manual.info,  Node: connector-net-news-6-3-5,  Next: connector-net-news-6-3-4,  Prev: connector-net-news-6-3-6,  Up: connector-net-news-6-3-x

D.4.2.5 Changes in MySQL Connector/Net 6.3.5 (12 October 2010)
..............................................................

This release fixes bugs since 6.3.4.

*Bugs Fixed*

   * A typed dataset did not get the table name.  (Bug #57894, Bug
     #11764989)

   * Setting `MySqlCommand.CommandTimeout' to 0 had no effect. It
     should have resulted in an infinite timeout.  (Bug #57265)

   * When performing a row-by-row update, only the first row was
     updated and all other rows were ignored.  (Bug #57092)

   * MySQL Connector/Net experienced two problems as follows:

       1. A call to `System.Data.Objects.ObjectContext.DatabaseExists()'
          returned false, even if the database existed.

       2. A call to `System.Data.Objects.ObjectContext.CreateDatabase()'
          created a database but with a name other than the one
          specified in the connection string. It then failed to use it
          when EDM objects were processed.

     (Bug #56859)

   * Setting the `Default Command Timeout' connection string option had
     no effect.  (Bug #56806)

   * When an output parameter was declared as type `MySqlDbType.Bit',
     it failed to return with the correct value.  (Bug #56756)

   * `MySqlHelper.ExecuteReader' did not include an overload accepting
     `MySqlParameter' objects when using a `MySqlConnection'. However,
     `MySqlHelper' did include an overload for `MySqlParameter' objects
     when using a string object containing the connection string to the
     database.  (Bug #56755)

   * MySQL Connector/Net 6.1.3 (GA) would not install on a Windows
     Server 2008 (Web Edition) clean installation. There were two
     problems:

        * If .NET framework version 4.0 was not installed, installation
          failed because c:\windows\microsoft.net\v4.0.* did not exist.

        * If .NET 4.0 was subsequently installed, then the following
          error was generated:

               InstallFiles: File: MySql.Data.Entity.dll,  Directory: ,  Size: 229888
               MSI (s) (E0:AC) [15:20:26:196]: Assembly Error:The assembly is built by a runtime newer
               than the currently loaded runtime, and cannot be loaded.
               MSI (s) (E0:AC) [15:20:26:196]: Note: 1: 1935 2:  3: 0x8013101B 4: IStream 5: Commit 6:
               MSI (s) (E0:A0) [15:20:26:196]: Note: 1: 1304 2: MySql.Data.Entity.dll
               Error 1304. Error writing to file: MySql.Data.Entity.dll. Verify that you have access to
               that directory.

     (Bug #56580)


File: manual.info,  Node: connector-net-news-6-3-4,  Next: connector-net-news-6-3-3,  Prev: connector-net-news-6-3-5,  Up: connector-net-news-6-3-x

D.4.2.6 Changes in MySQL Connector/Net 6.3.4 (01 September 2010 GA)
...................................................................

First GA release. This release fixes bugs since 6.3.3.

*Bugs Fixed*

   * The calculation of `lockAge' in the Session Provider sometimes
     generated a `System.Data.SqlTypes.SqlNullValueException'.  (Bug
     #55701)

   * Attempting to read `Double.MinValue' from a `DOUBLE' column in
     MySQL table generated the following exception:

          System.OverflowException : Value was either too large or too small for a Double.

          --OverflowException
          at System.Number.ParseDouble(String value, NumberStyles options, NumberFormatInfo
          numfmt)
          at MySql.Data.Types.MySqlDouble.MySql.Data.Types.IMySqlValue.ReadValue(MySqlPacket
          packet, Int64 length, Boolean nullVal)
          at MySql.Data.MySqlClient.NativeDriver.ReadColumnValue(Int32 index, MySqlField field,
          IMySqlValue valObject)
          at MySql.Data.MySqlClient.ResultSet.ReadColumnData(Boolean outputParms)
          at MySql.Data.MySqlClient.ResultSet.NextRow(CommandBehavior behavior)
          at MySql.Data.MySqlClient.MySqlDataReader.Read()

     (Bug #55644)

   * Calling `MySqlDataAdapter.Update(DataTable)' resulted in an
     unacceptable performance hit when updating large amounts of data.
     (Bug #55609)

   * If using MySQL Server 5.0.x it was not possible to alter stored
     routines in Visual Studio. If the stored routine was clicked, and
     the context sensitive menu option, Alter Routine, selected, the
     following error was generated:

          Unable to load object with error: Object reference not
          set to an instance of an object

     (Bug #55170)

   * EventLog was not disposed in the SessionState provider.  (Bug
     #52550)

   * When attempting to carry out an operation such as:

          from p in db.Products where p.PostedDate>=DateTime.Now select p;

     Where `p.PostedDate' is a `DateTimeOffset', and the underlying
     column type is a `TIMESTAMP', the following exception was
     generated:

          MySqlException occurred
          Unable to serialize date/time value

     MySQL Connector/Net has now been changed so that all `TIMESTAMP'
     columns will be surfaced as `DateTime'.  (Bug #52550)

   * Stored procedure enumeration code generated an error if a
     procedure was used in a dataset that did not return any resultsets.
     (Bug #50671)

   * The `INSERT' command was significantly slower with MySQL
     Connector/Net 6.x compared to 5.x, when compression was enabled.
     (Bug #48243)

   * Opening a connection in the Visual Studio Server Explorer and
     choosing to alter an existing routine required another
     authentication at the server.  (Bug #44715)


File: manual.info,  Node: connector-net-news-6-3-3,  Next: connector-net-news-6-3-2,  Prev: connector-net-news-6-3-4,  Up: connector-net-news-6-3-x

D.4.2.7 Changes in MySQL Connector/Net 6.3.3 (27 July 2010)
...........................................................

This release fixes bugs since 6.3.2.

*Bugs Fixed*

   * `MySqlDataAdapter.Update()' generated concurrency violations for
     custom stored procedure driven update commands that used
     `UpdateRowSource.FirstReturnedRecord'.  (Bug #54895)

   * Several calls to `DataAdapter.Update()' with intervening changes
     to `DataTable' resulted in `ConcurrencyException' exceptions being
     generated.  (Bug #54863)

   * MySQL Connector/Net generated a null reference exception when
     `TransactionScope' was used by multiple threads.  (Bug #54681)

   * The icon for the MySQL Web Configuration Tool was not displayed in
     Visual Studio for Web Application Projects.  (Bug #54571)

   * The `MySqlHelper' object did not have an overloaded version of the
     `ExecuteReader' method that accepted a `MySqlConnection' object.
     (Bug #54570)

   * If `MySqlDataAdapter' was used with an `INSERT' command where the
     `VALUES' clause contained an expression with parentheses in it,
     and set the `adapter.UpdateBatchSize' parameter to be greater than
     one, then the call to `adapter.Update' either generated an
     exception or failed to batch the commands, executing each insert
     individually.  (Bug #54386)

   * The method `MySql.Data.Common.QueryNormalizer.CollapseValueList'
     generated an `ArgumentOutOfRangeException'.  (Bug #54152, Bug
     #53865)

   * MySQL Connector/Net did not process `Thread.Abort()' correctly,
     and failed to cancel queries currently running on the server.
     (Bug #54012)

   * MySQL Connector/Net 6.3.2 failed to install on Windows Vista.
     (Bug #53975)

   * Garbage Collector disposal of a `MySqlConnection' object caused
     the following exception:

          System.IO.EndOfStreamException: Attempted to read past the end of the stream.
          MySql.Data.MySqlClient.MySqlStream.ReadFully(Stream stream, Byte[] buffer, Int32 offset,
          Int32 count)
          MySql.Data.MySqlClient.MySqlStream.LoadPacket()
          Outer Exception Reading from the stream has failed.
          ...

     (Bug #53457)

   * MySQL Connector/Net did not throw an `EndOfStreamException'
     exception when `net_write_timeout' was exceeded.  (Bug #53439)

   * After a timeout exception, if an attempt was made to reuse a
     connection returned to the connection pool the following exception
     was generated:

          [MySqlException (0x80004005): There is already an open DataReader associated with this
          Connection which must be closed first.]
             MySql.Data.MySqlClient.MySqlCommand.CheckState() +278
             MySql.Data.MySqlClient.MySqlCommand.ExecuteReader(CommandBehavior behavior) +43
             MySql.Data.MySqlClient.MySqlCommand.ExecuteReader() +6
             Controls.SimpleCommand.ExecuteReader(String SQL) in ...:323
             Albums.GetImagesByAlbum(SimpleCommand Cmd, Int32 iAlbum, String Order, String Limit)
          in ...:13
             Forecast.Page_Load(Object sender, EventArgs e) in ...:70
             System.Web.UI.Control.OnLoad(EventArgs e) +99
             System.Web.UI.Control.LoadRecursive() +50
             System.Web.UI.Page.ProcessRequestMain(Boolean includeStagesBeforeAsyncPoint, Boolean
          includeStagesAfterAsyncPoint) +627

     (Bug #53357)

   * Membership schema creation failed if the default schema collation
     was not Latin1.  (Bug #53174)

   * The MySQL Connector/Net installation failed due to
     `machine.config' files not being present in configuration folders.

     MySQL Connector/Net has been changed to skip over configuration
     folders that do not contain a `machine.config' file.  (Bug #52352)

   * `CHAR(36)' columns were not recognized as GUIDs when used in views
     with entity models.  (Bug #52085)

   * When an application was subjected to increased concurrent load,
     MySQL Connector/Net generated the following error when calling
     stored procedures:

          A DataTable named \'Procedure Parameters\'
          already belongs to this DataSet.

     (Bug #49118)

   * When the connection string option `Connection Reset = True' was
     used, a connection reset used the previously used encoding for the
     subsequent authentication operation. This failed, for example, if
     UCS2 was used to read the last column before the reset.  (Bug
     #47153)

   * When batching was used in `MySqlDataAdapter', a connection was not
     opened automatically in `MySqlDataAdapter.Update()'. This resulted
     in an `InvalidOperationException' exception being generated, with
     the message text `connection must be valid and open'.

     MySQL Connector/Net has been changed to behave more like SQL
     Server: if the connection is closed, it is opened for the duration
     of update operation.  (Bug #38411)

   * Database name was emitted into typed datasets. This prevented
     users using the configured default database.  (Bug #33870)


File: manual.info,  Node: connector-net-news-6-3-2,  Next: connector-net-news-6-3-1,  Prev: connector-net-news-6-3-3,  Up: connector-net-news-6-3-x

D.4.2.8 Changes in MySQL Connector/Net 6.3.2 (24 May 2010 beta)
...............................................................

First Beta release. This release fixes bugs since 6.3.1.

*Functionality Added or Changed*

   * Procedure cacheing had a problem whereby if you created a
     procedure, dropped it, and recreated it with a different number of
     parameters an exception was generated.

     MySQL Connector/Net has been changed so that if the procedure is
     recreated with a different number of parameters, it will still be
     recognized.  (Bug #52562)

   * MySQL Connector/Net has been changed to include
     `MySqlDataReader.GetFieldType(string columnname)'. Further,
     `MySqlDataReader.GetOrdinal()' now includes the name of the column
     in the exception if the column is not found.  (Bug #47467)

*Bugs Fixed*

   * After an exception, the internal datareader,
     `MySqlCommand.Connection.Reader', was not properly closed (it was
     not set to null). If another query was subsequently executed on
     that command object an exception was generated with the message
     `There is already an open DataReader associated with this
     Connection which must be closed first.' (Bug #55558)

   * MySQL Connector/Net generated an exception when used to read a
     `TEXT' column containing more than 32767 bytes.  (Bug #54040)

   * In MySQL Connector/Net, the `MySqlConnection.Abort()' method
     contained a `try...catch' construct, with an empty `catch' block.
     This meant that any exception generated at this point would not be
     caught.  (Bug #52769)

   * The procedure cache affected the MySQL Connector/Net performance,
     reducing it by around 65%. This was due to unnecessary calls of
     `String.Format()', related to debug logging.  Even though the
     logging was disabled the string was still being formatted,
     resulting in impaired performance.  (Bug #52475)

   * If `FunctionsReturnString=true' was used in the connection string,
     the decimal separator (according to locale) was not interpreted.
     (Bug #52187)

   * In MySQL Connector/Net, the `LoadCharsetMap()' function of the
     `CharSetMap' class set the following incorrect mapping:

          mapping.Add("latin1", new CharacterSet("latin1", 1));

     This meant that, for example, the Euro sign was not handled
     correctly.

     The correct mapping should have been:

          mapping.Add("latin1", new CharacterSet("windows-1252", 1));

     This is because MySQL's `latin1' character set is the same as the
     `windows-cp1252' character set and it extends the official ISO
     8859-1 or IANA latin1.  (Bug #51927)

   * A non-terminated string in SQL threw a CLR exception rather than a
     syntax exception.  (Bug #51788)

   * When calling `ExecuteNonQuery' on a command object, the following
     exception occurred:

          Index and length must refer to a location within the string.
          Parameter name: length

     (Bug #51610)

   * MySQL Connector/Net 6.3.1 failed to install.  (Bug #51407, Bug
     #51604)

   * When using table per type inheritance and listing the contents of
     the parent table, the result of the query was a list of child
     objects, even though there was no related child record with the
     same parent Id.  (Bug #49850)


File: manual.info,  Node: connector-net-news-6-3-1,  Next: connector-net-news-6-3-0,  Prev: connector-net-news-6-3-2,  Up: connector-net-news-6-3-x

D.4.2.9 Changes in MySQL Connector/Net 6.3.1 (02 March 2010)
............................................................

This release fixes bugs since 6.3.0.

*Functionality Added or Changed*

   * Connector/Net was not compatible with Visual Studio wizards that
     used square brackets to delimit symbols.

     Connector/Net has been changed to include a new connection string
     option `Sql Server mode' that supports use of square brackets to
     delimit symbols.  (Bug #35852)

*Bugs Fixed*

   * Specifying a connection string where an option had no value
     generated an error, rather than the value being set to the
     default. For example, a connection string such as the following
     would result in an error:

          server=localhost;user=root;compress=;database=test;port=3306;password=123456;

     (Bug #51209)

   * The method `Command.TrimSemicolons' used `StringBuilder', and
     therefore allocated memory for the query even if it did not need
     to be trimmed. This led to excessive memory consumption when
     executing a number of large queries.  (Bug #51149)

   * `MySqlCommand.Parameters.Clear()' did not work.  (Bug #50444)

   * Binary Columns were not displayed in the Query Builder of Visual
     Studio.  (Bug #50171)

   * When the `UpdateBatchSize' property was set to a value greater
     than 1, only the first row was applied to the database.  (Bug
     #50123)

   * When trying to create stored procedures from an SQL script, a
     `MySqlException' was thrown when attempting to redefine the
     `DELIMITER':

                  MySql.Data.MySqlClient.MySqlException was unhandled
                  Message="You have an error in your SQL syntax; check the manual that corresponds to your
                  MySQL server version for the right syntax to use near 'DELIMITER' at line 1"
                  Source="MySql.Data"
                  ErrorCode=-2147467259
                  Number=1064
                  StackTrace:
                  a` MySql.Data.MySqlClient.MySqlStream.ReadPacket()
                  a` MySql.Data.MySqlClient.NativeDriver.ReadResult(UInt64& affectedRows, Int64&
                  lastInsertId)
                  a` MySql.Data.MySqlClient.MySqlDataReader.GetResultSet()
                  a` MySql.Data.MySqlClient.MySqlDataReader.NextResult()
                  a` MySql.Data.MySqlClient.MySqlCommand.ExecuteReader(CommandBehavior behavior)
                  a` MySql.Data.MySqlClient.MySqlCommand.ExecuteReader()
                  a` MySql.Data.MySqlClient.MySqlCommand.ExecuteNonQuery()
                a` MySql.Data.MySqlClient.MySqlScript.Execute()

     Note: The `MySqlScript' class has been fixed to support the
     delimiter statement as it is found in SQL scripts.  (Bug #46429)

   * A connection string set in `web.config' could not be reused after
     Visual Studio 2008 Professional was shut down. It continued
     working for the existing controls, but did not work for new
     controls added.  (Bug #41629)


File: manual.info,  Node: connector-net-news-6-3-0,  Prev: connector-net-news-6-3-1,  Up: connector-net-news-6-3-x

D.4.2.10 Changes in MySQL Connector/Net 6.3.0 (16 February 2010 alpha)
......................................................................

First alpha release of 6.3.

*Functionality Added or Changed*

   * Nested transaction scopes were not supported. MySQL Connector/Net
     now implements nested transaction scopes. A per-thread stack of
     scopes is maintained, which is necessary to handle nested scopes
     with the `RequiresNew' or `Suppress' options.  (Bug #45098)

   * Support for MySQL Server 4.1 has been removed from MySQL
     Connector/Net starting with version 6.3.0. The connector will now
     throw an exception if you try to connect to a server of version
     less than 5.0.

*Bugs Fixed*

   * When adding a data set in Visual Studio 2008, the following error
     was generated:

          Relations couldn't be addded. Column 'REFERENCED_TABLE_CATALOG' does not belong to table.

     This was due to a 'REFERENCED_TABLE_CATALOG' column not being
     included in the foreign keys collection.  (Bug #48974)

   * Attempting to execute a load data local infile on a file where the
     user did not have write permissions, or the file was open in an
     editor gave an access denied error.  (Bug #48944)

   * The method `MySqlDataReader.GetSchemaTable()' returned 0 in the
     `NumericPrecision' field for decimal and newdecimal columns.  (Bug
     #48171)


File: manual.info,  Node: connector-net-news-6-2-x,  Next: connector-net-news-6-1-x,  Prev: connector-net-news-6-3-x,  Up: connector-net-news

D.4.3 Changes in MySQL Connector/Net Version 6.2.x
--------------------------------------------------

* Menu:

* connector-net-news-6-2-6::     Changes in MySQL Connector/Net 6.2.6 (Not yet released)
* connector-net-news-6-2-5::     Changes in MySQL Connector/Net 6.2.5 (01 July 2011)
* connector-net-news-6-2-4::     Changes in MySQL Connector/Net 6.2.4 (30 August 2010)
* connector-net-news-6-2-3::     Changes in MySQL Connector/Net 6.2.3 (10 April 2010)
* connector-net-news-6-2-2::     Changes in MySQL Connector/Net 6.2.2 (22 December 2009 GA)
* connector-net-news-6-2-1::     Changes in MySQL Connector/Net 6.2.1 (16 November 2009 beta)
* connector-net-news-6-2-0::     Changes in MySQL Connector/Net 6.2.0 (21 October 2009 alpha)


File: manual.info,  Node: connector-net-news-6-2-6,  Next: connector-net-news-6-2-5,  Prev: connector-net-news-6-2-x,  Up: connector-net-news-6-2-x

D.4.3.1 Changes in MySQL Connector/Net 6.2.6 (Not yet released)
...............................................................

This release fixes bugs since 6.2.5.

*Bugs Fixed*

   * `MySqlScript' was modified to enable correct processing of the
     `DELIMITER' command when not followed by a new line.  (Bug #61680,
     Bug #12732279)

   * The ASP.NET membership provider was modified to create and query
     all related tables using lowercase names.  (Bug #61108, Bug
     #12702009)

   * On Model First changed column types generated in SQL scripts to
     produce more suitable `MySql' types.  (Bug #59244, Bug #12707104)


File: manual.info,  Node: connector-net-news-6-2-5,  Next: connector-net-news-6-2-4,  Prev: connector-net-news-6-2-6,  Up: connector-net-news-6-2-x

D.4.3.2 Changes in MySQL Connector/Net 6.2.5 (01 July 2011)
...........................................................

This release fixes bugs since 6.2.4.

*Bugs Fixed*

   * `SchemaDefinition-5.5.ssdl' was modified to treat `CHAR(36)'
     columns as a GUID.  (Bug #61657, Bug #12708208)

   * `SqlFragment.QuoteIdentifier' was modified to add MySQL quotes
     around identifiers.  (Bug #61635, Bug #12707285)

   * Modified `MySqlConnection.BeginTransaction' to throw a
     `NotSupportedException' for `Snapshot' isolation level.  (Bug
     #61589, Bug #12698020)

   * `MysqlDataReader.GetSchemaTable' returned incorrect values and
     types.  (Bug #59989, Bug #11776346)

   * All queries other than `INSERT' were executed individually instead
     of as a batch even though batching was enabled for the connection.
     (Bug #59616, Bug #11850286)

   * MySQL Connector/Net generated an exception when executing a query
     consisting of ';', for example:

          mycmd(";",mycon)
          mycmd.executenonquery()

     The exception generated was:

          System.IndexOutOfRangeException: Index was outside the bounds of the array.
             at MySql.Data.MySqlClient.MySqlCommand.TrimSemicolons(String sql)
             at MySql.Data.MySqlClient.MySqlCommand.ExecuteReader(CommandBehavior behavior)
             at MySql.Data.MySqlClient.MySqlCommand.ExecuteReader()
             at MySql.Data.MySqlClient.MySqlCommand.ExecuteNonQuery()

     (Bug #59537, Bug #11766433)

   * Setting `Membership.ApplicationName' had no effect.  (Bug #59438,
     Bug #11770465)

   * A `NullReferenceException' was thrown on disposal of a
     `TransactionScope' object.  (Bug #59346, Bug #11766272)

   * `MembershipProvider' did not generate hashes correctly if the
     algorithm was keyed. The Key of the algorithm should have been set
     if the `HashAlgorithm' was `KeyedHashAlgorithm'.  (Bug #58906)

   * Code introduced to fix bug #54863 proved problematic on .NET
     version 3.5 and above.  (Bug #58853)

   * The `MySqlTokenizer' contained unnecessary `Substring' and `Trim'
     calls:

          string token = sql.Substring(startIndex, stopIndex - startIndex).Trim();

     The variable `token' was not used anywhere in the code.  (Bug
     #58757)

   * `MySqlCommand.ExecuteReader(CommandBehavior)' threw a
     `NullReferenceException' when being called with
     `CommandBehavior.CloseConnection', if the SQL statement contained
     a syntax error, or contained invalid data such as an invalid
     column name.  (Bug #58652)

   * `ReadFieldLength()' returned incorrect value for `BIGINT'
     autoincrement columns.  (Bug #58373)

   * MySQL Connector/Net did not support the `utf8mb4' character set.
     When attempting to connect to `utf8mb4' tables or columns, an
     exception `KeyNotFoundException' was generated.  (Bug #58244)

   * A typed dataset did not get the table name.  (Bug #57894, Bug
     #11764989)

   * Setting `MySqlCommand.CommandTimeout' to 0 had no effect. It
     should have resulted in an infinite timeout.  (Bug #57265)

   * When performing a row-by-row update, only the first row was
     updated and all other rows were ignored.  (Bug #57092)

   * Setting the `Default Command Timeout' connection string option had
     no effect.  (Bug #56806)

   * When an output parameter was declared as type `MySqlDbType.Bit',
     it failed to return with the correct value.  (Bug #56756)

   * `MySqlHelper.ExecuteReader' did not include an overload accepting
     `MySqlParameter' objects when using a `MySqlConnection'. However,
     `MySqlHelper' did include an overload for `MySqlParameter' objects
     when using a string object containing the connection string to the
     database.  (Bug #56755)

   * Default values returned for text columns were not quoted. This
     meant that the `COLUMN_DEFAULT' field of the `GetSchema' columns
     collection did not return a valid SQL expression.  (Bug #56509)

   * MySQL Connector/Net for .NET/Mono attempted to dynamically load
     the assembly `Mono.Posix.dll' when a Unix socket was used to
     connect to the server. This failed and the connector was not able
     to use a Unix socket unless the `Mono.Posix.dll' assembly was
     previously loaded by the program.  (Bug #56410)

   * Modified `ProviderManifest.xml' to map `TIMESTAMP' database
     columns to the `DateTime' .NET type.  (Bug #55351, Bug #12652602)

   * The ADO.NET Entity Data Model could not add stored procedures from
     MySQL Server 5.0.45 but worked fine using MySQL Server 5.1.  (Bug
     #55349)

   * Fixed Entity Framework provider `GROUP BY' clause generation by
     adding all group-by keys to the `SELECT' statement.  (Bug #46742,
     Bug #12622129)


File: manual.info,  Node: connector-net-news-6-2-4,  Next: connector-net-news-6-2-3,  Prev: connector-net-news-6-2-5,  Up: connector-net-news-6-2-x

D.4.3.3 Changes in MySQL Connector/Net 6.2.4 (30 August 2010)
.............................................................

This release fixes bugs since 6.2.3.

*Functionality Added or Changed*

   * Procedure cacheing had a problem whereby if you created a
     procedure, dropped it, and recreated it with a different number of
     parameters an exception was generated.

     MySQL Connector/Net has been changed so that if the procedure is
     recreated with a different number of parameters, it will still be
     recognized.  (Bug #52562)

*Bugs Fixed*

   * The calculation of `lockAge' in the Session Provider sometimes
     generated a `System.Data.SqlTypes.SqlNullValueException'.  (Bug
     #55701)

   * Attempting to read `Double.MinValue' from a `DOUBLE' column in
     MySQL table generated the following exception:

          System.OverflowException : Value was either too large or too small for a Double.

          --OverflowException
          at System.Number.ParseDouble(String value, NumberStyles options, NumberFormatInfo
          numfmt)
          at MySql.Data.Types.MySqlDouble.MySql.Data.Types.IMySqlValue.ReadValue(MySqlPacket
          packet, Int64 length, Boolean nullVal)
          at MySql.Data.MySqlClient.NativeDriver.ReadColumnValue(Int32 index, MySqlField field,
          IMySqlValue valObject)
          at MySql.Data.MySqlClient.ResultSet.ReadColumnData(Boolean outputParms)
          at MySql.Data.MySqlClient.ResultSet.NextRow(CommandBehavior behavior)
          at MySql.Data.MySqlClient.MySqlDataReader.Read()

     (Bug #55644)

   * After an exception, the internal datareader,
     `MySqlCommand.Connection.Reader', was not properly closed (it was
     not set to null). If another query was subsequently executed on
     that command object an exception was generated with the message
     `There is already an open DataReader associated with this
     Connection which must be closed first.' (Bug #55558)

   * If using MySQL Server 5.0.x it was not possible to alter stored
     routines in Visual Studio. If the stored routine was clicked, and
     the context sensitive menu option, Alter Routine, selected, the
     following error was generated:

          Unable to load object with error: Object reference not
          set to an instance of an object

     (Bug #55170)

   * `MySqlDataAdapter.Update()' generated concurrency violations for
     custom stored procedure driven update commands that used
     `UpdateRowSource.FirstReturnedRecord'.  (Bug #54895)

   * Several calls to `DataAdapter.Update()' with intervening changes
     to `DataTable' resulted in `ConcurrencyException' exceptions being
     generated.  (Bug #54863)

   * The icon for the MySQL Web Configuration Tool was not displayed in
     Visual Studio for Web Application Projects.  (Bug #54571)

   * The `MySqlHelper' object did not have an overloaded version of the
     `ExecuteReader' method that accepted a `MySqlConnection' object.
     (Bug #54570)

   * If `MySqlDataAdapter' was used with an `INSERT' command where the
     `VALUES' clause contained an expression with parentheses in it,
     and set the `adapter.UpdateBatchSize' parameter to be greater than
     one, then the call to `adapter.Update' either generated an
     exception or failed to batch the commands, executing each insert
     individually.  (Bug #54386)

   * The method `MySql.Data.Common.QueryNormalizer.CollapseValueList'
     generated an `ArgumentOutOfRangeException'.  (Bug #54152, Bug
     #53865)

   * MySQL Connector/Net did not process `Thread.Abort()' correctly,
     and failed to cancel queries currently running on the server.
     (Bug #54012)

   * Garbage Collector disposal of a `MySqlConnection' object caused
     the following exception:

          System.IO.EndOfStreamException: Attempted to read past the end of the stream.
          MySql.Data.MySqlClient.MySqlStream.ReadFully(Stream stream, Byte[] buffer, Int32 offset,
          Int32 count)
          MySql.Data.MySqlClient.MySqlStream.LoadPacket()
          Outer Exception Reading from the stream has failed.
          ...

     (Bug #53457)

   * MySQL Connector/Net did not throw an `EndOfStreamException'
     exception when `net_write_timeout' was exceeded.  (Bug #53439)

   * After a timeout exception, if an attempt was made to reuse a
     connection returned to the connection pool the following exception
     was generated:

          [MySqlException (0x80004005): There is already an open DataReader associated with this
          Connection which must be closed first.]
             MySql.Data.MySqlClient.MySqlCommand.CheckState() +278
             MySql.Data.MySqlClient.MySqlCommand.ExecuteReader(CommandBehavior behavior) +43
             MySql.Data.MySqlClient.MySqlCommand.ExecuteReader() +6
             Controls.SimpleCommand.ExecuteReader(String SQL) in ...:323
             Albums.GetImagesByAlbum(SimpleCommand Cmd, Int32 iAlbum, String Order, String Limit)
          in ...:13
             Forecast.Page_Load(Object sender, EventArgs e) in ...:70
             System.Web.UI.Control.OnLoad(EventArgs e) +99
             System.Web.UI.Control.LoadRecursive() +50
             System.Web.UI.Page.ProcessRequestMain(Boolean includeStagesBeforeAsyncPoint, Boolean
          includeStagesAfterAsyncPoint) +627

     (Bug #53357)

   * Membership schema creation failed if the default schema collation
     was not Latin1.  (Bug #53174)

   * In MySQL Connector/Net, the `MySqlConnection.Abort()' method
     contained a `try...catch' construct, with an empty `catch' block.
     This meant that any exception generated at this point would not be
     caught.  (Bug #52769)

   * EventLog was not disposed in the SessionState provider.  (Bug
     #52550)

   * The procedure cache affected the MySQL Connector/Net performance,
     reducing it by around 65%. This was due to unnecessary calls of
     `String.Format()', related to debug logging.  Even though the
     logging was disabled the string was still being formatted,
     resulting in impaired performance.  (Bug #52475)

   * If `FunctionsReturnString=true' was used in the connection string,
     the decimal separator (according to locale) was not interpreted.
     (Bug #52187)

   * Periodically the session provider threw an `SqlNullValueException'
     exception. When this happened, the row within the
     `my_aspnet_Sessions' table had `locked' always set to '1'. The
     locked status never changed back to '0' and the user experienced
     the exception on every page, until their browser was closed and
     reopened (recreating a new sessionID), or the `locked' value was
     manually changed to '0'.  (Bug #52175)

   * `CHAR(36)' columns were not recognized as GUIDs when used in views
     with entity models.  (Bug #52085)

   * In MySQL Connector/Net, the `LoadCharsetMap()' function of the
     `CharSetMap' class set the following incorrect mapping:

          mapping.Add("latin1", new CharacterSet("latin1", 1));

     This meant that, for example, the Euro sign was not handled
     correctly.

     The correct mapping should have been:

          mapping.Add("latin1", new CharacterSet("windows-1252", 1));

     This is because MySQL's `latin1' character set is the same as the
     `windows-cp1252' character set and it extends the official ISO
     8859-1 or IANA latin1.  (Bug #51927)

   * Stored procedure enumeration code generated an error if a
     procedure was used in a dataset that did not return any resultsets.
     (Bug #50671)

   * When an application was subjected to increased concurrent load,
     MySQL Connector/Net generated the following error when calling
     stored procedures:

          A DataTable named \'Procedure Parameters\'
          already belongs to this DataSet.

     (Bug #49118)

   * In the ADO.NET Entity Data Model Wizard, the time to update a
     model scaled abnormally as the number of entities increased.  (Bug
     #48791, Bug #12596237)

   * The `INSERT' command was significantly slower with MySQL
     Connector/Net 6.x compared to 5.x, when compression was enabled.
     (Bug #48243)

   * When the connection string option `Connection Reset = True' was
     used, a connection reset used the previously used encoding for the
     subsequent authentication operation. This failed, for example, if
     UCS2 was used to read the last column before the reset.  (Bug
     #47153)

   * Opening a connection in the Visual Studio Server Explorer and
     choosing to alter an existing routine required another
     authentication at the server.  (Bug #44715)

   * When batching was used in `MySqlDataAdapter', a connection was not
     opened automatically in `MySqlDataAdapter.Update()'. This resulted
     in an `InvalidOperationException' exception being generated, with
     the message text `connection must be valid and open'.

     MySQL Connector/Net has been changed to behave more like SQL
     Server: if the connection is closed, it is opened for the duration
     of update operation.  (Bug #38411)

   * Database name was emitted into typed datasets. This prevented
     users using the configured default database.  (Bug #33870)


File: manual.info,  Node: connector-net-news-6-2-3,  Next: connector-net-news-6-2-2,  Prev: connector-net-news-6-2-4,  Up: connector-net-news-6-2-x

D.4.3.4 Changes in MySQL Connector/Net 6.2.3 (10 April 2010)
............................................................

This release fixes bugs since 6.2.2.

*Functionality Added or Changed*

   * MySQL Connector/Net has been changed to include
     `MySqlDataReader.GetFieldType(string columnname)'. Further,
     `MySqlDataReader.GetOrdinal()' now includes the name of the column
     in the exception if the column is not found.  (Bug #47467)

*Bugs Fixed*

   * A non-terminated string in SQL threw a CLR exception rather than a
     syntax exception.  (Bug #51788)

   * When calling `ExecuteNonQuery' on a command object, the following
     exception occurred:

          Index and length must refer to a location within the string.
          Parameter name: length

     (Bug #51610)

   * Specifying a connection string where an option had no value
     generated an error, rather than the value being set to the
     default. For example, a connection string such as the following
     would result in an error:

          server=localhost;user=root;compress=;database=test;port=3306;password=123456;

     (Bug #51209)

   * The method `Command.TrimSemicolons' used `StringBuilder', and
     therefore allocated memory for the query even if it did not need
     to be trimmed. This led to excessive memory consumption when
     executing a number of large queries.  (Bug #51149)

   * `MySqlCommand.Parameters.Clear()' did not work.  (Bug #50444)

   * When the `MySqlScript.execute()' method was called, the following
     exception was generated:

          InvalidOperationException : The CommandText property has not been properly initialized.

     (Bug #50344)

   * When using the Compact Framework the following exception occurred
     when attempting to connect to a MySQL Server:

          System.InvalidOperationException was unhandled
            Message="Timeouts are not supported on this stream."

     (Bug #50321)

   * Binary Columns were not displayed in the Query Builder of Visual
     Studio.  (Bug #50171)

   * When the `UpdateBatchSize' property was set to a value greater
     than 1, only the first row was applied to the database.  (Bug
     #50123)

   * When using table per type inheritance and listing the contents of
     the parent table, the result of the query was a list of child
     objects, even though there was no related child record with the
     same parent Id.  (Bug #49850)

   * `MySqlDataReader.GetUInt64' returned an incorrect value when
     reading a `BIGINT UNSIGNED' column containing a value greater than
     2147483647.  (Bug #49794)

   * A `FormatException' was generated when an empty string was
     returned from a stored function.  (Bug #49642)

   * When trying to create stored procedures from an SQL script, a
     `MySqlException' was thrown when attempting to redefine the
     `DELIMITER':

                  MySql.Data.MySqlClient.MySqlException was unhandled
                  Message="You have an error in your SQL syntax; check the manual that corresponds to your
                  MySQL server version for the right syntax to use near 'DELIMITER' at line 1"
                  Source="MySql.Data"
                  ErrorCode=-2147467259
                  Number=1064
                  StackTrace:
                  a` MySql.Data.MySqlClient.MySqlStream.ReadPacket()
                  a` MySql.Data.MySqlClient.NativeDriver.ReadResult(UInt64& affectedRows, Int64&
                  lastInsertId)
                  a` MySql.Data.MySqlClient.MySqlDataReader.GetResultSet()
                  a` MySql.Data.MySqlClient.MySqlDataReader.NextResult()
                  a` MySql.Data.MySqlClient.MySqlCommand.ExecuteReader(CommandBehavior behavior)
                  a` MySql.Data.MySqlClient.MySqlCommand.ExecuteReader()
                  a` MySql.Data.MySqlClient.MySqlCommand.ExecuteNonQuery()
                a` MySql.Data.MySqlClient.MySqlScript.Execute()

     Note: The `MySqlScript' class has been fixed to support the
     delimiter statement as it is found in SQL scripts.  (Bug #46429)

   * Calling a User Defined Function using Entity SQL in the Entity
     Framework caused a `NullReferenceException'.  (Bug #45277)

   * A connection string set in `web.config' could not be reused after
     Visual Studio 2008 Professional was shut down. It continued
     working for the existing controls, but did not work for new
     controls added.  (Bug #41629)


File: manual.info,  Node: connector-net-news-6-2-2,  Next: connector-net-news-6-2-1,  Prev: connector-net-news-6-2-3,  Up: connector-net-news-6-2-x

D.4.3.5 Changes in MySQL Connector/Net 6.2.2 (22 December 2009 GA)
..................................................................

First GA release of 6.2. This release fixes bugs since 6.2.1.

*Bugs Fixed*

   * When adding a data set in Visual Studio 2008, the following error
     was generated:

          Relations couldn't be addded. Column 'REFERENCED_TABLE_CATALOG' does not belong to table.

     This was due to a 'REFERENCED_TABLE_CATALOG' column not being
     included in the foreign keys collection.  (Bug #48974)

   * Attempting to execute a load data local infile on a file where the
     user did not have write permissions, or the file was open in an
     editor gave an access denied error.  (Bug #48944)

   * The method `MySqlDataReader.GetSchemaTable()' returned 0 in the
     `NumericPrecision' field for decimal and newdecimal columns.  (Bug
     #48171)

   * MySQL Connector/Net generated an invalid operation exception
     during a transaction rollback:

          System.InvalidOperationException: Connection must be valid and open to rollback
          transaction
             at MySql.Data.MySqlClient.MySqlTransaction.Rollback()
             at MySql.Data.MySqlClient.MySqlConnection.CloseFully()
             at
          MySql.Data.MySqlClient.MySqlPromotableTransaction.System.Transactions.IPromotableSinglePhaseNotification.Rollback(SinglePhaseEnlistment
          singlePhaseEnlistment)
          ...

     (Bug #35330)

   * Connection objects were not garbage collected when not in use.
     (Bug #31996)


File: manual.info,  Node: connector-net-news-6-2-1,  Next: connector-net-news-6-2-0,  Prev: connector-net-news-6-2-2,  Up: connector-net-news-6-2-x

D.4.3.6 Changes in MySQL Connector/Net 6.2.1 (16 November 2009 beta)
....................................................................

This release fixes bugs since 6.2.0.

*Functionality Added or Changed*

   * The `MySqlParameter' class now has a property named
     `PossibleValues'. This property is NULL unless the parameter is
     created by `MySqlCommandBuilder.DeriveParameters'.  Further, it
     will be NULL unless the parameter is of type enum or set - in this
     case it will be a list of strings that are the possible values for
     the column. This feature is designed as an aid to the developer.
     (Bug #48586)

   * Prior to MySQL Connector/Net 6.2, `MySqlCommand.CommandTimeout'
     included user processing time, that is processing time not related
     to direct use of the connector. Timeout was implemented through a
     .NET Timer, that triggered after `CommandTimeout' seconds.

     MySQL Connector/Net 6.2 introduced timeouts that are aligned with
     how Microsoft handles `SqlCommand.CommandTimeout'.  This property
     is the cumulative timeout for all network reads and writes during
     command execution or processing of the results. A timeout can
     still occur in the `MySqlReader.Read' method after the first row
     is returned, and does not include user processing time, only IO
     operations.

     Further details on this can be found in the relevant Microsoft
     documentation
     (http://msdn.microsoft.com/en-us/library/system.data.sqlclient.sqlcommand.commandtimeout.aspx).

   * Starting with MySQL Connector/Net 6.2, there is a background job
     that runs every three minutes and removes connections from pool
     that have been idle (unused) for more than three minutes. The pool
     cleanup frees resources on both client and server side. This is
     because on the client side every connection uses a socket, and on
     the server side every connection uses a socket and a thread.

     Prior to this change, connections were never removed from the
     pool, and the pool always contained the peak number of open
     connections. For example, a web application that peaked at 1000
     concurrent database connections would consume 1000 threads and
     1000 open sockets at the server, without ever freeing up those
     resources from the connection pool.

   * MySQL Connector/Net now supports the processing of certificates
     when connecting to an SSL-enabled MySQL Server. For further
     information see the connection string option SSL Mode in the
     section *Note connector-net-connection-options:: and the tutorial
     *Note connector-net-tutorials-ssl::.

*Bugs Fixed*

   * Cloning of `MySqlCommand' was not typesafe. To clone a
     `MySqlCommand' it was necessary to do:

                  MySqlCommand clone = (MySqlCommand)((ICloneable)comm).Clone();

     MySQL Connector/Net was changed so that it was possible to do:

                  MySqlCommand clone = comm.Clone();

     (Bug #48460)

   * When used, the `Encrypt' connection string option caused a
     `Keyword not supported' exception to be generated.

     This option is in fact obsolete, and the option SSL Mode should be
     used instead. Although the `Encrypt' option has been fixed so that
     it does not generate an exception, it will be removed completely
     in version 6.4.  (Bug #48290)

   * When building the `MySql.Data' project with .NET Framework 3.5
     installed, the following build output was displayed:

          Project file contains ToolsVersion="4.0", which is not supported by this version of
          MSBuild. Treating the project as if it had ToolsVersion="3.5".

     The project had been created using the .NET Framework 4.0, which
     was beta, instead of using the 3.5 framework.  (Bug #48271)

   * It was not possible to retrieve a value from a MySQL server table,
     if the value was larger than that supported by the .NET type
     `System.Decimal'.

     MySQL Connector/Net was changed to expose the `MySqlDecimal' type,
     along with the supporting method `GetMySqlDecimal'.  (Bug #48100)

   * An entity model created from a schema containing a table with a
     column of type `UNSIGNED BIGINT' and a view of the table did not
     behave correctly. When an entity was created and mapped to the
     view, the column that was of type `UNSIGNED BIGINT' was displayed
     as `BIGINT'.  (Bug #47872)

   * MySQL Connector/Net session support did not work with MySQL Server
     versions prior to 5.0, as the Session Provider used a call to
     `TIMESTAMPDIFF', which was not available on servers prior to 5.0.
     (Bug #47219)


File: manual.info,  Node: connector-net-news-6-2-0,  Prev: connector-net-news-6-2-1,  Up: connector-net-news-6-2-x

D.4.3.7 Changes in MySQL Connector/Net 6.2.0 (21 October 2009 alpha)
....................................................................

The first alpha release of 6.2.

*Bugs Fixed*

   * When using a `BINARY(16)' column to represent a GUID and having
     specified `old guids = true' in the connection string, the values
     were returned correctly until a null value was encountered in that
     field. After the null value was encountered a format exception was
     thrown with the following message:

          Guid should contain 32 digits with 4 dashes (xxxxxxxx-xxxx-xxxx-xxxx-xxxxxxxxxxxx).

     (Bug #47928)

   * The Session Provider created invalid `session expires' on a random
     basis.

     This was due to the fact that the Session Provider was incorrectly
     reading from the root `web.config', rather than from the
     application specific `web.config'.  (Bug #47815)

   * When loading the `MySQLClient-mono.sln' file included with the
     Connector/Net source into Mono Develop, the following error
     occurred:

          /home/tbedford/connector-net-src/6.1/MySQLClient-mono.sln(22):
          Unsupported or unrecognized project:
          '/home/tbedford/connector-net-src/6.1/Installer/Installer.wixproj'

     If the file was modified to remove this problem, then attempting
     to build the solution generated the following error:

          /home/tbedford/connector-net-src/6.1/MySql.Data/Provider/Source/Connection.cs(280,46):
          error CS0115: `MySql.Data.MySqlClient.MySqlConnection.DbProviderFactory' is marked as an
          override but no suitable property found to override

     (Bug #47048)


File: manual.info,  Node: connector-net-news-6-1-x,  Next: connector-net-news-6-0-x,  Prev: connector-net-news-6-2-x,  Up: connector-net-news

D.4.4 Changes in MySQL Connector/Net Version 6.1.x
--------------------------------------------------

* Menu:

* connector-net-news-6-1-7::     Changes in MySQL Connector/Net 6.1.7 (Not released GA)
* connector-net-news-6-1-6::     Changes in MySQL Connector/Net 6.1.6 (Not released GA)
* connector-net-news-6-1-5::     Changes in MySQL Connector/Net 6.1.5 (30 August 2010 GA)
* connector-net-news-6-1-4::     Changes in MySQL Connector/Net 6.1.4 (28 April 2010 GA)
* connector-net-news-6-1-3::     Changes in MySQL Connector/Net 6.1.3 (16 November 2009 GA)
* connector-net-news-6-1-2::     Changes in MySQL Connector/Net 6.1.2 (08 September 2009 GA)
* connector-net-news-6-1-1::     Changes in MySQL Connector/Net 6.1.1 (20 August 2009 beta)
* connector-net-news-6-1-0::     Changes in MySQL Connector/Net 6.1.0 (15 July 2009 alpha)


File: manual.info,  Node: connector-net-news-6-1-7,  Next: connector-net-news-6-1-6,  Prev: connector-net-news-6-1-x,  Up: connector-net-news-6-1-x

D.4.4.1 Changes in MySQL Connector/Net 6.1.7 (Not released GA)
..............................................................

This release fixes bugs since 6.1.6.

*Bugs Fixed*

   * `MySqlScript' was modified to enable correct processing of the
     `DELIMITER' command when not followed by a new line.  (Bug #61680,
     Bug #12732279)

   * `SchemaDefinition-5.5.ssdl' was modified to treat `CHAR(36)'
     columns as a GUID.  (Bug #61657, Bug #12708208)

   * `SqlFragment.QuoteIdentifier' was modified to add MySQL quotes
     around identifiers.  (Bug #61635, Bug #12707285)

   * The ASP.NET membership provider was modified to create and query
     all related tables using lowercase names.  (Bug #61108, Bug
     #12702009)


File: manual.info,  Node: connector-net-news-6-1-6,  Next: connector-net-news-6-1-5,  Prev: connector-net-news-6-1-7,  Up: connector-net-news-6-1-x

D.4.4.2 Changes in MySQL Connector/Net 6.1.6 (Not released GA)
..............................................................

This release fixes bugs since 6.1.5.

*Bugs Fixed*

   * Modified `MySqlConnection.BeginTransaction' to throw a
     `NotSupportedException' for `Snapshot' isolation level.  (Bug
     #61589, Bug #12698020)

   * `MysqlDataReader.GetSchemaTable' returned incorrect values and
     types.  (Bug #59989, Bug #11776346)

   * All queries other than `INSERT' were executed individually instead
     of as a batch even though batching was enabled for the connection.
     (Bug #59616, Bug #11850286)

   * MySQL Connector/Net generated an exception when executing a query
     consisting of ';', for example:

          mycmd(";",mycon)
          mycmd.executenonquery()

     The exception generated was:

          System.IndexOutOfRangeException: Index was outside the bounds of the array.
             at MySql.Data.MySqlClient.MySqlCommand.TrimSemicolons(String sql)
             at MySql.Data.MySqlClient.MySqlCommand.ExecuteReader(CommandBehavior behavior)
             at MySql.Data.MySqlClient.MySqlCommand.ExecuteReader()
             at MySql.Data.MySqlClient.MySqlCommand.ExecuteNonQuery()

     (Bug #59537, Bug #11766433)

   * Setting `Membership.ApplicationName' had no effect.  (Bug #59438,
     Bug #11770465)

   * `MembershipProvider' did not generate hashes correctly if the
     algorithm was keyed. The Key of the algorithm should have been set
     if the `HashAlgorithm' was `KeyedHashAlgorithm'.  (Bug #58906)

   * Code introduced to fix bug #54863 proved problematic on .NET
     version 3.5 and above.  (Bug #58853)

   * The `MySqlTokenizer' contained unnecessary `Substring' and `Trim'
     calls:

          string token = sql.Substring(startIndex, stopIndex - startIndex).Trim();

     The variable `token' was not used anywhere in the code.  (Bug
     #58757)

   * `MySqlCommand.ExecuteReader(CommandBehavior)' threw a
     `NullReferenceException' when being called with
     `CommandBehavior.CloseConnection', if the SQL statement contained
     a syntax error, or contained invalid data such as an invalid
     column name.  (Bug #58652)

   * `ReadFieldLength()' returned incorrect value for `BIGINT'
     autoincrement columns.  (Bug #58373)

   * MySQL Connector/Net did not support the `utf8mb4' character set.
     When attempting to connect to `utf8mb4' tables or columns, an
     exception `KeyNotFoundException' was generated.  (Bug #58244)

   * A typed dataset did not get the table name.  (Bug #57894, Bug
     #11764989)

   * Setting `MySqlCommand.CommandTimeout' to 0 had no effect. It
     should have resulted in an infinite timeout.  (Bug #57265)

   * When performing a row-by-row update, only the first row was
     updated and all other rows were ignored.  (Bug #57092)

   * Setting the `Default Command Timeout' connection string option had
     no effect.  (Bug #56806)

   * When an output parameter was declared as type `MySqlDbType.Bit',
     it failed to return with the correct value.  (Bug #56756)

   * `MySqlHelper.ExecuteReader' did not include an overload accepting
     `MySqlParameter' objects when using a `MySqlConnection'. However,
     `MySqlHelper' did include an overload for `MySqlParameter' objects
     when using a string object containing the connection string to the
     database.  (Bug #56755)

   * Default values returned for text columns were not quoted. This
     meant that the `COLUMN_DEFAULT' field of the `GetSchema' columns
     collection did not return a valid SQL expression.  (Bug #56509)

   * MySQL Connector/Net for .NET/Mono attempted to dynamically load
     the assembly `Mono.Posix.dll' when a Unix socket was used to
     connect to the server. This failed and the connector was not able
     to use a Unix socket unless the `Mono.Posix.dll' assembly was
     previously loaded by the program.  (Bug #56410)

   * Modified `ProviderManifest.xml' to map `TIMESTAMP' database
     columns to the `DateTime' .NET type.  (Bug #55351, Bug #12652602)

   * The ADO.NET Entity Data Model could not add stored procedures from
     MySQL Server 5.0.45 but worked fine using MySQL Server 5.1.  (Bug
     #55349)

   * Fixed Entity Framework provider `GROUP BY' clause generation by
     adding all group-by keys to the `SELECT' statement.  (Bug #46742,
     Bug #12622129)


File: manual.info,  Node: connector-net-news-6-1-5,  Next: connector-net-news-6-1-4,  Prev: connector-net-news-6-1-6,  Up: connector-net-news-6-1-x

D.4.4.3 Changes in MySQL Connector/Net 6.1.5 (30 August 2010 GA)
................................................................

This release fixes bugs since 6.1.4.

*Bugs Fixed*

   * The calculation of `lockAge' in the Session Provider sometimes
     generated a `System.Data.SqlTypes.SqlNullValueException'.  (Bug
     #55701)

   * Attempting to read `Double.MinValue' from a `DOUBLE' column in
     MySQL table generated the following exception:

          System.OverflowException : Value was either too large or too small for a Double.

          --OverflowException
          at System.Number.ParseDouble(String value, NumberStyles options, NumberFormatInfo
          numfmt)
          at MySql.Data.Types.MySqlDouble.MySql.Data.Types.IMySqlValue.ReadValue(MySqlPacket
          packet, Int64 length, Boolean nullVal)
          at MySql.Data.MySqlClient.NativeDriver.ReadColumnValue(Int32 index, MySqlField field,
          IMySqlValue valObject)
          at MySql.Data.MySqlClient.ResultSet.ReadColumnData(Boolean outputParms)
          at MySql.Data.MySqlClient.ResultSet.NextRow(CommandBehavior behavior)
          at MySql.Data.MySqlClient.MySqlDataReader.Read()

     (Bug #55644)

   * If using MySQL Server 5.0.x it was not possible to alter stored
     routines in Visual Studio. If the stored routine was clicked, and
     the context sensitive menu option, Alter Routine, selected, the
     following error was generated:

          Unable to load object with error: Object reference not
          set to an instance of an object

     (Bug #55170)

   * `MySqlDataAdapter.Update()' generated concurrency violations for
     custom stored procedure driven update commands that used
     `UpdateRowSource.FirstReturnedRecord'.  (Bug #54895)

   * Several calls to `DataAdapter.Update()' with intervening changes
     to `DataTable' resulted in `ConcurrencyException' exceptions being
     generated.  (Bug #54863)

   * The icon for the MySQL Web Configuration Tool was not displayed in
     Visual Studio for Web Application Projects.  (Bug #54571)

   * The `MySqlHelper' object did not have an overloaded version of the
     `ExecuteReader' method that accepted a `MySqlConnection' object.
     (Bug #54570)

   * If `MySqlDataAdapter' was used with an `INSERT' command where the
     `VALUES' clause contained an expression with parentheses in it,
     and set the `adapter.UpdateBatchSize' parameter to be greater than
     one, then the call to `adapter.Update' either generated an
     exception or failed to batch the commands, executing each insert
     individually.  (Bug #54386)

   * The method `MySql.Data.Common.QueryNormalizer.CollapseValueList'
     generated an `ArgumentOutOfRangeException'.  (Bug #54152, Bug
     #53865)

   * Garbage Collector disposal of a `MySqlConnection' object caused
     the following exception:

          System.IO.EndOfStreamException: Attempted to read past the end of the stream.
          MySql.Data.MySqlClient.MySqlStream.ReadFully(Stream stream, Byte[] buffer, Int32 offset,
          Int32 count)
          MySql.Data.MySqlClient.MySqlStream.LoadPacket()
          Outer Exception Reading from the stream has failed.
          ...

     (Bug #53457)

   * MySQL Connector/Net did not throw an `EndOfStreamException'
     exception when `net_write_timeout' was exceeded.  (Bug #53439)

   * After a timeout exception, if an attempt was made to reuse a
     connection returned to the connection pool the following exception
     was generated:

          [MySqlException (0x80004005): There is already an open DataReader associated with this
          Connection which must be closed first.]
             MySql.Data.MySqlClient.MySqlCommand.CheckState() +278
             MySql.Data.MySqlClient.MySqlCommand.ExecuteReader(CommandBehavior behavior) +43
             MySql.Data.MySqlClient.MySqlCommand.ExecuteReader() +6
             Controls.SimpleCommand.ExecuteReader(String SQL) in ...:323
             Albums.GetImagesByAlbum(SimpleCommand Cmd, Int32 iAlbum, String Order, String Limit)
          in ...:13
             Forecast.Page_Load(Object sender, EventArgs e) in ...:70
             System.Web.UI.Control.OnLoad(EventArgs e) +99
             System.Web.UI.Control.LoadRecursive() +50
             System.Web.UI.Page.ProcessRequestMain(Boolean includeStagesBeforeAsyncPoint, Boolean
          includeStagesAfterAsyncPoint) +627

     (Bug #53357)

   * Membership schema creation failed if the default schema collation
     was not Latin1.  (Bug #53174)

   * EventLog was not disposed in the SessionState provider.  (Bug
     #52550)

   * `CHAR(36)' columns were not recognized as GUIDs when used in views
     with entity models.  (Bug #52085)

   * Stored procedure enumeration code generated an error if a
     procedure was used in a dataset that did not return any resultsets.
     (Bug #50671)

   * When an application was subjected to increased concurrent load,
     MySQL Connector/Net generated the following error when calling
     stored procedures:

          A DataTable named \'Procedure Parameters\'
          already belongs to this DataSet.

     (Bug #49118)

   * In the ADO.NET Entity Data Model Wizard, the time to update a
     model scaled abnormally as the number of entities increased.  (Bug
     #48791, Bug #12596237)

   * The `INSERT' command was significantly slower with MySQL
     Connector/Net 6.x compared to 5.x, when compression was enabled.
     (Bug #48243)

   * When the connection string option `Connection Reset = True' was
     used, a connection reset used the previously used encoding for the
     subsequent authentication operation. This failed, for example, if
     UCS2 was used to read the last column before the reset.  (Bug
     #47153)

   * Opening a connection in the Visual Studio Server Explorer and
     choosing to alter an existing routine required another
     authentication at the server.  (Bug #44715)

   * When batching was used in `MySqlDataAdapter', a connection was not
     opened automatically in `MySqlDataAdapter.Update()'. This resulted
     in an `InvalidOperationException' exception being generated, with
     the message text `connection must be valid and open'.

     MySQL Connector/Net has been changed to behave more like SQL
     Server: if the connection is closed, it is opened for the duration
     of update operation.  (Bug #38411)

   * Database name was emitted into typed datasets. This prevented
     users using the configured default database.  (Bug #33870)


File: manual.info,  Node: connector-net-news-6-1-4,  Next: connector-net-news-6-1-3,  Prev: connector-net-news-6-1-5,  Up: connector-net-news-6-1-x

D.4.4.4 Changes in MySQL Connector/Net 6.1.4 (28 April 2010 GA)
...............................................................

This release fixes bugs since 6.1.3.

*Functionality Added or Changed*

   * Procedure cacheing had a problem whereby if you created a
     procedure, dropped it, and recreated it with a different number of
     parameters an exception was generated.

     MySQL Connector/Net has been changed so that if the procedure is
     recreated with a different number of parameters, it will still be
     recognized.  (Bug #52562)

   * MySQL Connector/Net has been changed to include
     `MySqlDataReader.GetFieldType(string columnname)'. Further,
     `MySqlDataReader.GetOrdinal()' now includes the name of the column
     in the exception if the column is not found.  (Bug #47467)

*Bugs Fixed*

   * In MySQL Connector/Net, the `MySqlConnection.Abort()' method
     contained a `try...catch' construct, with an empty `catch' block.
     This meant that any exception generated at this point would not be
     caught.  (Bug #52769)

   * If `FunctionsReturnString=true' was used in the connection string,
     the decimal separator (according to locale) was not interpreted.
     (Bug #52187)

   * In MySQL Connector/Net, the `LoadCharsetMap()' function of the
     `CharSetMap' class set the following incorrect mapping:

          mapping.Add("latin1", new CharacterSet("latin1", 1));

     This meant that, for example, the Euro sign was not handled
     correctly.

     The correct mapping should have been:

          mapping.Add("latin1", new CharacterSet("windows-1252", 1));

     This is because MySQL's `latin1' character set is the same as the
     `windows-cp1252' character set and it extends the official ISO
     8859-1 or IANA latin1.  (Bug #51927)

   * A non-terminated string in SQL threw a CLR exception rather than a
     syntax exception.  (Bug #51788)

   * When calling `ExecuteNonQuery' on a command object, the following
     exception occurred:

          Index and length must refer to a location within the string.
          Parameter name: length

     (Bug #51610)

   * The method `Command.TrimSemicolons' used `StringBuilder', and
     therefore allocated memory for the query even if it did not need
     to be trimmed. This led to excessive memory consumption when
     executing a number of large queries.  (Bug #51149)

   * `MySqlCommand.Parameters.Clear()' did not work.  (Bug #50444)

   * When the `MySqlScript.execute()' method was called, the following
     exception was generated:

          InvalidOperationException : The CommandText property has not been properly initialized.

     (Bug #50344)

   * Binary Columns were not displayed in the Query Builder of Visual
     Studio.  (Bug #50171)

   * When the `UpdateBatchSize' property was set to a value greater
     than 1, only the first row was applied to the database.  (Bug
     #50123)

   * When using table per type inheritance and listing the contents of
     the parent table, the result of the query was a list of child
     objects, even though there was no related child record with the
     same parent Id.  (Bug #49850)

   * `MySqlDataReader.GetUInt64' returned an incorrect value when
     reading a `BIGINT UNSIGNED' column containing a value greater than
     2147483647.  (Bug #49794)

   * A `FormatException' was generated when an empty string was
     returned from a stored function.  (Bug #49642)

   * When adding a data set in Visual Studio 2008, the following error
     was generated:

          Relations couldn't be addded. Column 'REFERENCED_TABLE_CATALOG' does not belong to table.

     This was due to a 'REFERENCED_TABLE_CATALOG' column not being
     included in the foreign keys collection.  (Bug #48974)

   * Attempting to execute a load data local infile on a file where the
     user did not have write permissions, or the file was open in an
     editor gave an access denied error.  (Bug #48944)

   * The method `MySqlDataReader.GetSchemaTable()' returned 0 in the
     `NumericPrecision' field for decimal and newdecimal columns.  (Bug
     #48171)

   * When trying to create stored procedures from an SQL script, a
     `MySqlException' was thrown when attempting to redefine the
     `DELIMITER':

                  MySql.Data.MySqlClient.MySqlException was unhandled
                  Message="You have an error in your SQL syntax; check the manual that corresponds to your
                  MySQL server version for the right syntax to use near 'DELIMITER' at line 1"
                  Source="MySql.Data"
                  ErrorCode=-2147467259
                  Number=1064
                  StackTrace:
                  a` MySql.Data.MySqlClient.MySqlStream.ReadPacket()
                  a` MySql.Data.MySqlClient.NativeDriver.ReadResult(UInt64& affectedRows, Int64&
                  lastInsertId)
                  a` MySql.Data.MySqlClient.MySqlDataReader.GetResultSet()
                  a` MySql.Data.MySqlClient.MySqlDataReader.NextResult()
                  a` MySql.Data.MySqlClient.MySqlCommand.ExecuteReader(CommandBehavior behavior)
                  a` MySql.Data.MySqlClient.MySqlCommand.ExecuteReader()
                  a` MySql.Data.MySqlClient.MySqlCommand.ExecuteNonQuery()
                a` MySql.Data.MySqlClient.MySqlScript.Execute()

     Note: The `MySqlScript' class has been fixed to support the
     delimiter statement as it is found in SQL scripts.  (Bug #46429)

   * Calling a User Defined Function using Entity SQL in the Entity
     Framework caused a `NullReferenceException'.  (Bug #45277)

   * A connection string set in `web.config' could not be reused after
     Visual Studio 2008 Professional was shut down. It continued
     working for the existing controls, but did not work for new
     controls added.  (Bug #41629)


File: manual.info,  Node: connector-net-news-6-1-3,  Next: connector-net-news-6-1-2,  Prev: connector-net-news-6-1-4,  Up: connector-net-news-6-1-x

D.4.4.5 Changes in MySQL Connector/Net 6.1.3 (16 November 2009 GA)
..................................................................

This release fixes bugs since 6.1.2.

*Bugs Fixed*

   * Cloning of `MySqlCommand' was not typesafe. To clone a
     `MySqlCommand' it was necessary to do:

                  MySqlCommand clone = (MySqlCommand)((ICloneable)comm).Clone();

     MySQL Connector/Net was changed so that it was possible to do:

                  MySqlCommand clone = comm.Clone();

     (Bug #48460)

   * When building the `MySql.Data' project with .NET Framework 3.5
     installed, the following build output was displayed:

          Project file contains ToolsVersion="4.0", which is not supported by this version of
          MSBuild. Treating the project as if it had ToolsVersion="3.5".

     The project had been created using the .NET Framework 4.0, which
     was beta, instead of using the 3.5 framework.  (Bug #48271)

   * If `MySqlConnection.GetSchema' was called for "Indexes" on a table
     named `b`a`d' as follows:

          DataTable schemaPrimaryKeys = connection.GetSchema(
            "Indexes",
            new string[] { null, schemaName, "b`a`d"});

     Then the following exception was generated:

          You have an error in your SQL syntax; check the manual that corresponds to
          your MySQL server version for the right syntax to use near 'a`d`' at line 1

     (Bug #48101)

   * It was not possible to retrieve a value from a MySQL server table,
     if the value was larger than that supported by the .NET type
     `System.Decimal'.

     MySQL Connector/Net was changed to expose the `MySqlDecimal' type,
     along with the supporting method `GetMySqlDecimal'.  (Bug #48100)

   * For some character sets such as UTF-8, a `CHAR' column would
     sometimes be incorrectly interpreted as a `GUID' by MySQL
     Connector/Net.

     MySQL Connector/Net was changed so that a column would only be
     interpreted as a `GUID' if it had a character length of 36, as
     opposed to a byte length of 36.  (Bug #47985)

   * When using a `BINARY(16)' column to represent a GUID and having
     specified `old guids = true' in the connection string, the values
     were returned correctly until a null value was encountered in that
     field. After the null value was encountered a format exception was
     thrown with the following message:

          Guid should contain 32 digits with 4 dashes (xxxxxxxx-xxxx-xxxx-xxxx-xxxxxxxxxxxx).

     (Bug #47928)

   * An entity model created from a schema containing a table with a
     column of type `UNSIGNED BIGINT' and a view of the table did not
     behave correctly. When an entity was created and mapped to the
     view, the column that was of type `UNSIGNED BIGINT' was displayed
     as `BIGINT'.  (Bug #47872)

   * The Session Provider created invalid `session expires' on a random
     basis.

     This was due to the fact that the Session Provider was incorrectly
     reading from the root `web.config', rather than from the
     application specific `web.config'.  (Bug #47815)

   * Attempting to build MySQL Connector/Net 6.1 `MySQL.Data' from
     source code on Windows failed with the following error:

          ...\clones\6.1\MySql.Data\Provider\Source\NativeDriver.cs(519,29): error CS0122:
          'MySql.Data.MySqlClient.MySqlPacket.MySqlPacket()' is inaccessible due to its protection level

     (Bug #47354)

   * When tables were auto created for the Session State Provider they
     were set to use the MySQL Server's default collation, rather than
     the default collation set for the containing database.  (Bug
     #47332)

   * When loading the `MySQLClient-mono.sln' file included with the
     Connector/Net source into Mono Develop, the following error
     occurred:

          /home/tbedford/connector-net-src/6.1/MySQLClient-mono.sln(22):
          Unsupported or unrecognized project:
          '/home/tbedford/connector-net-src/6.1/Installer/Installer.wixproj'

     If the file was modified to remove this problem, then attempting
     to build the solution generated the following error:

          /home/tbedford/connector-net-src/6.1/MySql.Data/Provider/Source/Connection.cs(280,46):
          error CS0115: `MySql.Data.MySqlClient.MySqlConnection.DbProviderFactory' is marked as an
          override but no suitable property found to override

     (Bug #47048)


File: manual.info,  Node: connector-net-news-6-1-2,  Next: connector-net-news-6-1-1,  Prev: connector-net-news-6-1-3,  Up: connector-net-news-6-1-x

D.4.4.6 Changes in MySQL Connector/Net 6.1.2 (08 September 2009 GA)
...................................................................

This is the first GA release of 6.1. This release fixes bugs since
6.1.1.

*Bugs Fixed*

   * The MySQL Connector/Net Session State Provider truncated session
     data to 64KB, due to its column types being set to `BLOB'.  (Bug
     #47339)

   * MySQL Connector/Net generated the following exception when using
     the Session State provider:

          You have an error in your SQL syntax; check the manual that corresponds to your MySQL
          server version for the right syntax to use near 'MINUTEWHERE SessionId =
          'dtmgga55x35oi255nrfrxe45' AND ApplicationId = 1 AND Loc' at line 1
          Description: An unhandled exception occurred during the execution of the current web
          request. Please review the stack trace for more information about the error and where it
          originated in the code.

          Exception Details: MySql.Data.MySqlClient.MySqlException: You have an error in your SQL
          syntax; check the manual that corresponds to your MySQL server version for the right
          syntax to use near 'MINUTEWHERE SessionId = 'dtmgga55x35oi255nrfrxe45' AND ApplicationId =
          1 AND Loc' at line 1

     (Bug #46939)

   * If an error occurred during connection to a MySQL Server,
     deserializing the error message from the packet buffer caused a
     `NullReferenceException' to be thrown. When the method
     `MySqlPacket::ReadString()' attempted to retrieve the error
     message, the following line of code threw the exception:

                  string s = encoding.GetString(bits, (int)buffer.Position, end - (int)buffer.Position);

     This was due to the fact that the encoding field had not been
     initialized correctly.  (Bug #46844)

   * Input parameters were missing from Stored Procedures when using
     them with ADO.NET Data Entities.  (Bug #44985)

   * MySQL Connector/Net did not time out correctly. The command
     timeout was set to 30 secs, but MySQL Connector/Net hung for
     several hours.  (Bug #43761)


File: manual.info,  Node: connector-net-news-6-1-1,  Next: connector-net-news-6-1-0,  Prev: connector-net-news-6-1-2,  Up: connector-net-news-6-1-x

D.4.4.7 Changes in MySQL Connector/Net 6.1.1 (20 August 2009 beta)
..................................................................

This is the first Beta release of 6.1.

*Bugs Fixed*

   * In the `MySqlDataReader' class the `GetSByte' function returned a
     `byte' value instead of an `sbyte' value.  (Bug #46620)

   * The MySQL Connector/Net Profile Provider,
     `MySql.Web.Profile.MySQLProfileProvider', generated an error when
     running on Mono. When an attempt was made to save a string in
     `Profile.Name' the string was not saved to the
     `my_aspnet_Profiles' table. If an attempt was made to force the
     save with `Profile.Save()' the following error was generated:

                  Server Error in '/mono' Application

                  --------------------------------------------------------------------------------

                  The requested feature is not implemented.
                  Description: HTTP 500. Error processing request.

                  Stack Trace:

                  System.NotImplementedException: The requested feature is not implemented.
                  at MySql.Data.MySqlClient.MySqlConnection.EnlistTransaction
                  (System.Transactions.Transaction transaction) [0x00000]
                  at MySql.Data.MySqlClient.MySqlConnection.Open () [0x00000]
                  at MySql.Web.Profile.MySQLProfileProvider.SetPropertyValues
                  (System.Configuration.SettingsContext context,
                  System.Configuration.SettingsPropertyValueCollection collection) [0x00000]

                  --------------------------------------------------------------------------------
                  Version information: Mono Version: 2.0.50727.1433; ASP.NET Version: 2.0.50727.1433

     (Bug #46375)

   * An exception was generated when using `TIMESTAMP' columns with the
     Entity Framework.  (Bug #46311)

   * MySQL Connector/Net sometimes hung, without generating an
     exception. This happened if a read from a stream failed returning
     a 0, causing the code in `LoadPacket()' to enter an infinite loop.
     (Bug #46308)

   * When using MySQL Connector/Net 6.0.4 and a MySQL Server 4.1 an
     exception was generated when trying to execute:

                  connection.GetSchema("Columns", ...);

     The exception generated was:

                  'connection.GetSchema("Columns")' threw an exception of type
                  'System.ArgumentException'System.Data.DataTable {System.ArgumentException}
                  base{"Input string was not in a correct format.Couldn't store <'Select'> in
                  NUMERIC_PRECISION Column.  Expected type is UInt64."}System.Exception
                  {System.ArgumentException}

     (Bug #46270)

   * The MySQL Connector/Net method
     `StoredProcedure.GetParameters(string)' ignored the programmer's
     setting of the `UseProcedureBodies' option. This broke any
     application for which the application's parameter names did not
     match the parameter names in the Stored Procedure, resulting in an
     `ArgumentException' with the message `Parameter 'foo' not found in
     the collection.' and the following stack trace:

                  MySql.Data.dll!MySql.Data.MySqlClient.MySqlParameterCollection.GetParameterFlexible(stri
                  ng parameterName = "pStart", bool throwOnNotFound = true) Line 459C#
                  MySql.Data.dll!MySql.Data.MySqlClient.StoredProcedure.Resolve() Line 157 + 0x25
                  bytesC#
                  MySql.Data.dll!MySql.Data.MySqlClient.MySqlCommand.ExecuteReader(System.Data.CommandBeha
                  vior behavior = SequentialAccess) Line 405 + 0xb bytesC#
                  MySql.Data.dll!MySql.Data.MySqlClient.MySqlCommand.ExecuteDbDataReader(System.Data.Comma
                  ndBehavior behavior = SequentialAccess) Line 884 + 0xb bytesC#
                  System.Data.dll!System.Data.Common.DbCommand.System.Data.IDbCommand.ExecuteReader(System
                  .Data.CommandBehavior behavior) + 0xb bytes
                  System.Data.dll!System.Data.Common.DbDataAdapter.FillInternal(System.Data.DataSet
                  dataset = {System.Data.DataSet}, System.Data.DataTable[] datatables = null, int
                  startRecord = 0, int maxRecords = 0, string srcTable = "Table", System.Data.IDbCommand
                  command = {MySql.Data.MySqlClient.MySqlCommand}, System.Data.CommandBehavior behavior) +
                  0x83 bytes
                  System.Data.dll!System.Data.Common.DbDataAdapter.Fill(System.Data.DataSet dataSet, int
                  startRecord, int maxRecords, string srcTable, System.Data.IDbCommand command,
                  System.Data.CommandBehavior behavior) + 0x120 bytes
                  System.Data.dll!System.Data.Common.DbDataAdapter.Fill(System.Data.DataSet dataSet) +
                  0x5f bytes

     (Bug #46213)

   * Conversion of MySQL `TINYINT(1)' to `boolean' failed.  (Bug
     #46205, Bug #46359, Bug #41953)

   * When populating a MySQL database table in Visual Studio using the
     Table Editor, if a `VARCHAR(10)' column was changed to a
     `VARCHAR(20)' column an exception was generated:

                  SystemArgumentException: DataGridViewComboBoxCell value is not valid.
                To replace this default dialog please handle the DataError Event.

     (Bug #46100)

   * The Entity Framework provider was not calling `DBSortExpression'
     correctly when the `Skip' and `Take' methods were used, such as in
     the following statement:

                  TestModel.tblquarantine.OrderByDescending(q => q.MsgDate).Skip(100).Take(100).ToList();

     This resulted in the data being unsorted.  (Bug #45723)

   * The MySQL Connector/Net 6.0.4 installer failed with an error. The
     error message generated was:

                  There is a problem with this Windows Installer package. A DLL required for this
                  install to complete could not be run. Contact your support personnel or package vendor.

     When `OK' was clicked to acknowledge the error the installer
     exited.  (Bug #45474)

   * Calling the Entity Framework `SaveChanges()' method of any MySQL
     ORM Entity with a column type `TIME', generated an error message:

          Unknown PrimitiveKind Time

     (Bug #45457)

   * Insert into two tables failed when using the Entity Framework.
     The exception generated was:

                  The value given is not an instance of type 'Edm.Int32'

     (Bug #45077)

   * Errors occurred when using the Entity Framework with cultures that
     used a comma as the decimal separator. This was because the
     formatting for `SINGLE', `DOUBLE' and `DECIMAL' values was not
     handled correctly.  (Bug #44455)

   * When attempting to connect to MySQL using the Compact Framework
     version of MySQL Connector/Net, an `IndexOutOfRangeException'
     exception was generated on trying to open the connection.  (Bug
     #43736)

   * When reading data, such as with a `MySqlDataAdapter' on a
     `MySqlConnection', MySQL Connector/Net could potentially enter an
     infinite loop in `CompressedStream.ReadNextpacket()' if
     compression was enabled.  (Bug #43678)

   * An error occurred when building MySQL Connector/Net from source
     code checked out from the public SVN repository. This happened on
     Linux using Mono and Nant. The Mono JIT compiler version was
     1.2.6.0. The Nant version was 0.85.

     When an attempt was made to build (for example) the MySQL
     Connector/Net 5.2 branch using the command:

                  $ nant -buildfile:Client.build

     The following error occurred:

                  BUILD FAILED

                  Error loading buildfile.
                  Encoding name 'Windows-1252' not supported.
                  Parameter name: name

     (Bug #42411)

   * MySQL Connector/Net CHM documentation stated that MySQL Server
     3.23 was supported.  (Bug #42110)

   * In the case of long network inactivity, especially when connection
     pooling was used, connections were sometimes dropped, for example,
     by firewalls.

     Note: The bugfix introduced a new `keepalive' parameter, which
     prevents disconnects by sending an empty TCP packet after a
     specified timeout.  (Bug #40684)

   * Calling a Stored Procedure with an output parameter through MySQL
     Connector/Net resulted in a memory leak. Calling the same Stored
     Procedure without an output parameter did not result in a memory
     leak.  (Bug #36027)


File: manual.info,  Node: connector-net-news-6-1-0,  Prev: connector-net-news-6-1-1,  Up: connector-net-news-6-1-x

D.4.4.8 Changes in MySQL Connector/Net 6.1.0 (15 July 2009 alpha)
.................................................................

This is the first Alpha release of 6.1.

*Functionality Added or Changed*

   * Changed GUID type - The backend representation of a guid type has
     been changed to be CHAR(36). This is so you can use the server
     UUID() function to populate a GUID table. UUID generates a 36
     character string. Developers of older applications can add `old
     guids=true' to the connection string and the old BINARY(16) type
     will be used instead.

   * Support for native output parameters - This is supported when
     connected to a server that supports native output parameters.
     This includes servers as of 5.5.3 and 6.0.8.

   * Session State Provider - This enables you to store the state of
     your website in a MySQL server.

   * Website Configuration Dialog - This is a new wizard that is
     activated by clicking a button on the toolbar at the top of the
     Visual Studio Solution Explorer. It works in conjunction with the
     ASP.Net administration pages, making it easier to activate and set
     advanced options for the different MySQL web providers included.


File: manual.info,  Node: connector-net-news-6-0-x,  Next: connector-net-news-5-3-x,  Prev: connector-net-news-6-1-x,  Up: connector-net-news

D.4.5 Changes in MySQL Connector/Net Version 6.0.x
--------------------------------------------------

* Menu:

* connector-net-news-6-0-8::     Changes in MySQL Connector/Net 6.0.8 (Not released)
* connector-net-news-6-0-7::     Changes in MySQL Connector/Net 6.0.7 (30 August 2010)
* connector-net-news-6-0-6::     Changes in MySQL Connector/Net 6.0.6 (28 April 2010)
* connector-net-news-6-0-5::     Changes in MySQL Connector/Net 6.0.5 (12 November 2009)
* connector-net-news-6-0-4::     Changes in MySQL Connector/Net 6.0.4 (16 June 2009)
* connector-net-news-6-0-3::     Changes in MySQL Connector/Net 6.0.3 (28 April 2009)
* connector-net-news-6-0-2::     Changes in MySQL Connector/Net 6.0.2 (07 April 2009 beta)
* connector-net-news-6-0-1::     Changes in MySQL Connector/Net 6.0.1 (02 April 2009 beta)
* connector-net-news-6-0-0::     Changes in MySQL Connector/Net 6.0.0 (02 March 2009 alpha)


File: manual.info,  Node: connector-net-news-6-0-8,  Next: connector-net-news-6-0-7,  Prev: connector-net-news-6-0-x,  Up: connector-net-news-6-0-x

D.4.5.1 Changes in MySQL Connector/Net 6.0.8 (Not released)
...........................................................

Fixes bugs since 6.0.7.

*Bugs Fixed*

   * `MysqlDataReader.GetSchemaTable' returned incorrect values and
     types.  (Bug #59989, Bug #11776346)

   * All queries other than `INSERT' were executed individually instead
     of as a batch even though batching was enabled for the connection.
     (Bug #59616, Bug #11850286)

   * MySQL Connector/Net generated an exception when executing a query
     consisting of ';', for example:

          mycmd(";",mycon)
          mycmd.executenonquery()

     The exception generated was:

          System.IndexOutOfRangeException: Index was outside the bounds of the array.
             at MySql.Data.MySqlClient.MySqlCommand.TrimSemicolons(String sql)
             at MySql.Data.MySqlClient.MySqlCommand.ExecuteReader(CommandBehavior behavior)
             at MySql.Data.MySqlClient.MySqlCommand.ExecuteReader()
             at MySql.Data.MySqlClient.MySqlCommand.ExecuteNonQuery()

     (Bug #59537, Bug #11766433)

   * Setting `Membership.ApplicationName' had no effect.  (Bug #59438,
     Bug #11770465)

   * `MembershipProvider' did not generate hashes correctly if the
     algorithm was keyed. The Key of the algorithm should have been set
     if the `HashAlgorithm' was `KeyedHashAlgorithm'.  (Bug #58906)

   * Code introduced to fix bug #54863 proved problematic on .NET
     version 3.5 and above.  (Bug #58853)

   * The `MySqlTokenizer' contained unnecessary `Substring' and `Trim'
     calls:

          string token = sql.Substring(startIndex, stopIndex - startIndex).Trim();

     The variable `token' was not used anywhere in the code.  (Bug
     #58757)

   * `MySqlCommand.ExecuteReader(CommandBehavior)' threw a
     `NullReferenceException' when being called with
     `CommandBehavior.CloseConnection', if the SQL statement contained
     a syntax error, or contained invalid data such as an invalid
     column name.  (Bug #58652)

   * `ReadFieldLength()' returned incorrect value for `BIGINT'
     autoincrement columns.  (Bug #58373)

   * MySQL Connector/Net did not support the `utf8mb4' character set.
     When attempting to connect to `utf8mb4' tables or columns, an
     exception `KeyNotFoundException' was generated.  (Bug #58244)

   * A typed dataset did not get the table name.  (Bug #57894, Bug
     #11764989)

   * Setting `MySqlCommand.CommandTimeout' to 0 had no effect. It
     should have resulted in an infinite timeout.  (Bug #57265)

   * When performing a row-by-row update, only the first row was
     updated and all other rows were ignored.  (Bug #57092)

   * Setting the `Default Command Timeout' connection string option had
     no effect.  (Bug #56806)

   * When an output parameter was declared as type `MySqlDbType.Bit',
     it failed to return with the correct value.  (Bug #56756)

   * Default values returned for text columns were not quoted. This
     meant that the `COLUMN_DEFAULT' field of the `GetSchema' columns
     collection did not return a valid SQL expression.  (Bug #56509)

   * MySQL Connector/Net for .NET/Mono attempted to dynamically load
     the assembly `Mono.Posix.dll' when a Unix socket was used to
     connect to the server. This failed and the connector was not able
     to use a Unix socket unless the `Mono.Posix.dll' assembly was
     previously loaded by the program.  (Bug #56410)

   * The ADO.NET Entity Data Model could not add stored procedures from
     MySQL Server 5.0.45 but worked fine using MySQL Server 5.1.  (Bug
     #55349)


File: manual.info,  Node: connector-net-news-6-0-7,  Next: connector-net-news-6-0-6,  Prev: connector-net-news-6-0-8,  Up: connector-net-news-6-0-x

D.4.5.2 Changes in MySQL Connector/Net 6.0.7 (30 August 2010)
.............................................................

Fixes bugs since 6.0.6.

*Bugs Fixed*

   * Attempting to read `Double.MinValue' from a `DOUBLE' column in
     MySQL table generated the following exception:

          System.OverflowException : Value was either too large or too small for a Double.

          --OverflowException
          at System.Number.ParseDouble(String value, NumberStyles options, NumberFormatInfo
          numfmt)
          at MySql.Data.Types.MySqlDouble.MySql.Data.Types.IMySqlValue.ReadValue(MySqlPacket
          packet, Int64 length, Boolean nullVal)
          at MySql.Data.MySqlClient.NativeDriver.ReadColumnValue(Int32 index, MySqlField field,
          IMySqlValue valObject)
          at MySql.Data.MySqlClient.ResultSet.ReadColumnData(Boolean outputParms)
          at MySql.Data.MySqlClient.ResultSet.NextRow(CommandBehavior behavior)
          at MySql.Data.MySqlClient.MySqlDataReader.Read()

     (Bug #55644)

   * `MySqlDataAdapter.Update()' generated concurrency violations for
     custom stored procedure driven update commands that used
     `UpdateRowSource.FirstReturnedRecord'.  (Bug #54895)

   * Several calls to `DataAdapter.Update()' with intervening changes
     to `DataTable' resulted in `ConcurrencyException' exceptions being
     generated.  (Bug #54863)

   * The `MySqlHelper' object did not have an overloaded version of the
     `ExecuteReader' method that accepted a `MySqlConnection' object.
     (Bug #54570)

   * If `MySqlDataAdapter' was used with an `INSERT' command where the
     `VALUES' clause contained an expression with parentheses in it,
     and set the `adapter.UpdateBatchSize' parameter to be greater than
     one, then the call to `adapter.Update' either generated an
     exception or failed to batch the commands, executing each insert
     individually.  (Bug #54386)

   * The method `MySql.Data.Common.QueryNormalizer.CollapseValueList'
     generated an `ArgumentOutOfRangeException'.  (Bug #54152, Bug
     #53865)

   * Garbage Collector disposal of a `MySqlConnection' object caused
     the following exception:

          System.IO.EndOfStreamException: Attempted to read past the end of the stream.
          MySql.Data.MySqlClient.MySqlStream.ReadFully(Stream stream, Byte[] buffer, Int32 offset,
          Int32 count)
          MySql.Data.MySqlClient.MySqlStream.LoadPacket()
          Outer Exception Reading from the stream has failed.
          ...

     (Bug #53457)

   * After a timeout exception, if an attempt was made to reuse a
     connection returned to the connection pool the following exception
     was generated:

          [MySqlException (0x80004005): There is already an open DataReader associated with this
          Connection which must be closed first.]
             MySql.Data.MySqlClient.MySqlCommand.CheckState() +278
             MySql.Data.MySqlClient.MySqlCommand.ExecuteReader(CommandBehavior behavior) +43
             MySql.Data.MySqlClient.MySqlCommand.ExecuteReader() +6
             Controls.SimpleCommand.ExecuteReader(String SQL) in ...:323
             Albums.GetImagesByAlbum(SimpleCommand Cmd, Int32 iAlbum, String Order, String Limit)
          in ...:13
             Forecast.Page_Load(Object sender, EventArgs e) in ...:70
             System.Web.UI.Control.OnLoad(EventArgs e) +99
             System.Web.UI.Control.LoadRecursive() +50
             System.Web.UI.Page.ProcessRequestMain(Boolean includeStagesBeforeAsyncPoint, Boolean
          includeStagesAfterAsyncPoint) +627

     (Bug #53357)

   * Membership schema creation failed if the default schema collation
     was not Latin1.  (Bug #53174)

   * EventLog was not disposed in the SessionState provider.  (Bug
     #52550)

   * Stored procedure enumeration code generated an error if a
     procedure was used in a dataset that did not return any resultsets.
     (Bug #50671)

   * When an application was subjected to increased concurrent load,
     MySQL Connector/Net generated the following error when calling
     stored procedures:

          A DataTable named \'Procedure Parameters\'
          already belongs to this DataSet.

     (Bug #49118)

   * In the ADO.NET Entity Data Model Wizard, the time to update a
     model scaled abnormally as the number of entities increased.  (Bug
     #48791, Bug #12596237)

   * The `INSERT' command was significantly slower with MySQL
     Connector/Net 6.x compared to 5.x, when compression was enabled.
     (Bug #48243)

   * When the connection string option `Connection Reset = True' was
     used, a connection reset used the previously used encoding for the
     subsequent authentication operation. This failed, for example, if
     UCS2 was used to read the last column before the reset.  (Bug
     #47153)

   * Opening a connection in the Visual Studio Server Explorer and
     choosing to alter an existing routine required another
     authentication at the server.  (Bug #44715)

   * When batching was used in `MySqlDataAdapter', a connection was not
     opened automatically in `MySqlDataAdapter.Update()'. This resulted
     in an `InvalidOperationException' exception being generated, with
     the message text `connection must be valid and open'.

     MySQL Connector/Net has been changed to behave more like SQL
     Server: if the connection is closed, it is opened for the duration
     of update operation.  (Bug #38411)

   * Database name was emitted into typed datasets. This prevented
     users using the configured default database.  (Bug #33870)


File: manual.info,  Node: connector-net-news-6-0-6,  Next: connector-net-news-6-0-5,  Prev: connector-net-news-6-0-7,  Up: connector-net-news-6-0-x

D.4.5.3 Changes in MySQL Connector/Net 6.0.6 (28 April 2010)
............................................................

Fixes bugs since 6.0.5.

*Functionality Added or Changed*

   * Procedure cacheing had a problem whereby if you created a
     procedure, dropped it, and recreated it with a different number of
     parameters an exception was generated.

     MySQL Connector/Net has been changed so that if the procedure is
     recreated with a different number of parameters, it will still be
     recognized.  (Bug #52562)

   * MySQL Connector/Net has been changed to include
     `MySqlDataReader.GetFieldType(string columnname)'. Further,
     `MySqlDataReader.GetOrdinal()' now includes the name of the column
     in the exception if the column is not found.  (Bug #47467)

*Bugs Fixed*

   * If using MySQL Server 5.0.x it was not possible to alter stored
     routines in Visual Studio. If the stored routine was clicked, and
     the context sensitive menu option, Alter Routine, selected, the
     following error was generated:

          Unable to load object with error: Object reference not
          set to an instance of an object

     (Bug #55170)

   * In MySQL Connector/Net, the `MySqlConnection.Abort()' method
     contained a `try...catch' construct, with an empty `catch' block.
     This meant that any exception generated at this point would not be
     caught.  (Bug #52769)

   * If `FunctionsReturnString=true' was used in the connection string,
     the decimal separator (according to locale) was not interpreted.
     (Bug #52187)

   * In MySQL Connector/Net, the `LoadCharsetMap()' function of the
     `CharSetMap' class set the following incorrect mapping:

          mapping.Add("latin1", new CharacterSet("latin1", 1));

     This meant that, for example, the Euro sign was not handled
     correctly.

     The correct mapping should have been:

          mapping.Add("latin1", new CharacterSet("windows-1252", 1));

     This is because MySQL's `latin1' character set is the same as the
     `windows-cp1252' character set and it extends the official ISO
     8859-1 or IANA latin1.  (Bug #51927)

   * A non-terminated string in SQL threw a CLR exception rather than a
     syntax exception.  (Bug #51788)

   * When calling `ExecuteNonQuery' on a command object, the following
     exception occurred:

          Index and length must refer to a location within the string.
          Parameter name: length

     (Bug #51610)

   * The method `Command.TrimSemicolons' used `StringBuilder', and
     therefore allocated memory for the query even if it did not need
     to be trimmed. This led to excessive memory consumption when
     executing a number of large queries.  (Bug #51149)

   * `MySqlCommand.Parameters.Clear()' did not work.  (Bug #50444)

   * When the `MySqlScript.execute()' method was called, the following
     exception was generated:

          InvalidOperationException : The CommandText property has not been properly initialized.

     (Bug #50344)

   * Binary Columns were not displayed in the Query Builder of Visual
     Studio.  (Bug #50171)

   * When the `UpdateBatchSize' property was set to a value greater
     than 1, only the first row was applied to the database.  (Bug
     #50123)

   * When using table per type inheritance and listing the contents of
     the parent table, the result of the query was a list of child
     objects, even though there was no related child record with the
     same parent Id.  (Bug #49850)

   * `MySqlDataReader.GetUInt64' returned an incorrect value when
     reading a `BIGINT UNSIGNED' column containing a value greater than
     2147483647.  (Bug #49794)

   * A `FormatException' was generated when an empty string was
     returned from a stored function.  (Bug #49642)

   * When adding a data set in Visual Studio 2008, the following error
     was generated:

          Relations couldn't be addded. Column 'REFERENCED_TABLE_CATALOG' does not belong to table.

     This was due to a 'REFERENCED_TABLE_CATALOG' column not being
     included in the foreign keys collection.  (Bug #48974)

   * Attempting to execute a load data local infile on a file where the
     user did not have write permissions, or the file was open in an
     editor gave an access denied error.  (Bug #48944)

   * The method `MySqlDataReader.GetSchemaTable()' returned 0 in the
     `NumericPrecision' field for decimal and newdecimal columns.  (Bug
     #48171)

   * When trying to create stored procedures from an SQL script, a
     `MySqlException' was thrown when attempting to redefine the
     `DELIMITER':

                  MySql.Data.MySqlClient.MySqlException was unhandled
                  Message="You have an error in your SQL syntax; check the manual that corresponds to your
                  MySQL server version for the right syntax to use near 'DELIMITER' at line 1"
                  Source="MySql.Data"
                  ErrorCode=-2147467259
                  Number=1064
                  StackTrace:
                  a` MySql.Data.MySqlClient.MySqlStream.ReadPacket()
                  a` MySql.Data.MySqlClient.NativeDriver.ReadResult(UInt64& affectedRows, Int64&
                  lastInsertId)
                  a` MySql.Data.MySqlClient.MySqlDataReader.GetResultSet()
                  a` MySql.Data.MySqlClient.MySqlDataReader.NextResult()
                  a` MySql.Data.MySqlClient.MySqlCommand.ExecuteReader(CommandBehavior behavior)
                  a` MySql.Data.MySqlClient.MySqlCommand.ExecuteReader()
                  a` MySql.Data.MySqlClient.MySqlCommand.ExecuteNonQuery()
                a` MySql.Data.MySqlClient.MySqlScript.Execute()

     Note: The `MySqlScript' class has been fixed to support the
     delimiter statement as it is found in SQL scripts.  (Bug #46429)

   * Calling a User Defined Function using Entity SQL in the Entity
     Framework caused a `NullReferenceException'.  (Bug #45277)

   * A connection string set in `web.config' could not be reused after
     Visual Studio 2008 Professional was shut down. It continued
     working for the existing controls, but did not work for new
     controls added.  (Bug #41629)


File: manual.info,  Node: connector-net-news-6-0-5,  Next: connector-net-news-6-0-4,  Prev: connector-net-news-6-0-6,  Up: connector-net-news-6-0-x

D.4.5.4 Changes in MySQL Connector/Net 6.0.5 (12 November 2009)
...............................................................

This is a new release, fixing recently discovered bugs.

*Bugs Fixed*

   * Cloning of `MySqlCommand' was not typesafe. To clone a
     `MySqlCommand' it was necessary to do:

                  MySqlCommand clone = (MySqlCommand)((ICloneable)comm).Clone();

     MySQL Connector/Net was changed so that it was possible to do:

                  MySqlCommand clone = comm.Clone();

     (Bug #48460)

   * If `MySqlConnection.GetSchema' was called for "Indexes" on a table
     named `b`a`d' as follows:

          DataTable schemaPrimaryKeys = connection.GetSchema(
            "Indexes",
            new string[] { null, schemaName, "b`a`d"});

     Then the following exception was generated:

          You have an error in your SQL syntax; check the manual that corresponds to
          your MySQL server version for the right syntax to use near 'a`d`' at line 1

     (Bug #48101)

   * It was not possible to retrieve a value from a MySQL server table,
     if the value was larger than that supported by the .NET type
     `System.Decimal'.

     MySQL Connector/Net was changed to expose the `MySqlDecimal' type,
     along with the supporting method `GetMySqlDecimal'.  (Bug #48100)

   * An entity model created from a schema containing a table with a
     column of type `UNSIGNED BIGINT' and a view of the table did not
     behave correctly. When an entity was created and mapped to the
     view, the column that was of type `UNSIGNED BIGINT' was displayed
     as `BIGINT'.  (Bug #47872)

   * When loading the `MySQLClient-mono.sln' file included with the
     Connector/Net source into Mono Develop, the following error
     occurred:

          /home/tbedford/connector-net-src/6.1/MySQLClient-mono.sln(22):
          Unsupported or unrecognized project:
          '/home/tbedford/connector-net-src/6.1/Installer/Installer.wixproj'

     If the file was modified to remove this problem, then attempting
     to build the solution generated the following error:

          /home/tbedford/connector-net-src/6.1/MySql.Data/Provider/Source/Connection.cs(280,46):
          error CS0115: `MySql.Data.MySqlClient.MySqlConnection.DbProviderFactory' is marked as an
          override but no suitable property found to override

     (Bug #47048)

   * If an error occurred during connection to a MySQL Server,
     deserializing the error message from the packet buffer caused a
     `NullReferenceException' to be thrown. When the method
     `MySqlPacket::ReadString()' attempted to retrieve the error
     message, the following line of code threw the exception:

                  string s = encoding.GetString(bits, (int)buffer.Position, end - (int)buffer.Position);

     This was due to the fact that the encoding field had not been
     initialized correctly.  (Bug #46844)

   * In the `MySqlDataReader' class the `GetSByte' function returned a
     `byte' value instead of an `sbyte' value.  (Bug #46620)

   * The MySQL Connector/Net Profile Provider,
     `MySql.Web.Profile.MySQLProfileProvider', generated an error when
     running on Mono. When an attempt was made to save a string in
     `Profile.Name' the string was not saved to the
     `my_aspnet_Profiles' table. If an attempt was made to force the
     save with `Profile.Save()' the following error was generated:

                  Server Error in '/mono' Application

                  --------------------------------------------------------------------------------

                  The requested feature is not implemented.
                  Description: HTTP 500. Error processing request.

                  Stack Trace:

                  System.NotImplementedException: The requested feature is not implemented.
                  at MySql.Data.MySqlClient.MySqlConnection.EnlistTransaction
                  (System.Transactions.Transaction transaction) [0x00000]
                  at MySql.Data.MySqlClient.MySqlConnection.Open () [0x00000]
                  at MySql.Web.Profile.MySQLProfileProvider.SetPropertyValues
                  (System.Configuration.SettingsContext context,
                  System.Configuration.SettingsPropertyValueCollection collection) [0x00000]

                  --------------------------------------------------------------------------------
                  Version information: Mono Version: 2.0.50727.1433; ASP.NET Version: 2.0.50727.1433

     (Bug #46375)

   * An exception was generated when using `TIMESTAMP' columns with the
     Entity Framework.  (Bug #46311)

   * MySQL Connector/Net sometimes hung, without generating an
     exception. This happened if a read from a stream failed returning
     a 0, causing the code in `LoadPacket()' to enter an infinite loop.
     (Bug #46308)

   * When using MySQL Connector/Net 6.0.4 and a MySQL Server 4.1 an
     exception was generated when trying to execute:

                  connection.GetSchema("Columns", ...);

     The exception generated was:

                  'connection.GetSchema("Columns")' threw an exception of type
                  'System.ArgumentException'System.Data.DataTable {System.ArgumentException}
                  base{"Input string was not in a correct format.Couldn't store <'Select'> in
                  NUMERIC_PRECISION Column.  Expected type is UInt64."}System.Exception
                  {System.ArgumentException}

     (Bug #46270)

   * The MySQL Connector/Net method
     `StoredProcedure.GetParameters(string)' ignored the programmer's
     setting of the `UseProcedureBodies' option. This broke any
     application for which the application's parameter names did not
     match the parameter names in the Stored Procedure, resulting in an
     `ArgumentException' with the message `Parameter 'foo' not found in
     the collection.' and the following stack trace:

                  MySql.Data.dll!MySql.Data.MySqlClient.MySqlParameterCollection.GetParameterFlexible(stri
                  ng parameterName = "pStart", bool throwOnNotFound = true) Line 459C#
                  MySql.Data.dll!MySql.Data.MySqlClient.StoredProcedure.Resolve() Line 157 + 0x25
                  bytesC#
                  MySql.Data.dll!MySql.Data.MySqlClient.MySqlCommand.ExecuteReader(System.Data.CommandBeha
                  vior behavior = SequentialAccess) Line 405 + 0xb bytesC#
                  MySql.Data.dll!MySql.Data.MySqlClient.MySqlCommand.ExecuteDbDataReader(System.Data.Comma
                  ndBehavior behavior = SequentialAccess) Line 884 + 0xb bytesC#
                  System.Data.dll!System.Data.Common.DbCommand.System.Data.IDbCommand.ExecuteReader(System
                  .Data.CommandBehavior behavior) + 0xb bytes
                  System.Data.dll!System.Data.Common.DbDataAdapter.FillInternal(System.Data.DataSet
                  dataset = {System.Data.DataSet}, System.Data.DataTable[] datatables = null, int
                  startRecord = 0, int maxRecords = 0, string srcTable = "Table", System.Data.IDbCommand
                  command = {MySql.Data.MySqlClient.MySqlCommand}, System.Data.CommandBehavior behavior) +
                  0x83 bytes
                  System.Data.dll!System.Data.Common.DbDataAdapter.Fill(System.Data.DataSet dataSet, int
                  startRecord, int maxRecords, string srcTable, System.Data.IDbCommand command,
                  System.Data.CommandBehavior behavior) + 0x120 bytes
                  System.Data.dll!System.Data.Common.DbDataAdapter.Fill(System.Data.DataSet dataSet) +
                  0x5f bytes

     (Bug #46213)

   * Conversion of MySQL `TINYINT(1)' to `boolean' failed.  (Bug
     #46205, Bug #46359, Bug #41953)

   * When populating a MySQL database table in Visual Studio using the
     Table Editor, if a `VARCHAR(10)' column was changed to a
     `VARCHAR(20)' column an exception was generated:

                  SystemArgumentException: DataGridViewComboBoxCell value is not valid.
                To replace this default dialog please handle the DataError Event.

     (Bug #46100)

   * In MySQL Connector/Net 6.0.4 using `GetProcData' generated an
     error because the `parameters' data table was only created if
     MySQL Server was at least version 6.0.6, or if the
     `UseProcedureBodies' connection string option was set to true.

     Also the `DeriveParameters' command generated a null reference
     exception. This was because the `parameters' data table, which was
     null, was used in a `for each' loop.  (Bug #45952)

   * The Entity Framework provider was not calling `DBSortExpression'
     correctly when the `Skip' and `Take' methods were used, such as in
     the following statement:

                  TestModel.tblquarantine.OrderByDescending(q => q.MsgDate).Skip(100).Take(100).ToList();

     This resulted in the data being unsorted.  (Bug #45723)

   * The `EscapeString' code carried out escaping by calling
     `string.Replace' multiple times. This resulted in a performance
     bottleneck, as for every line a new string was allocated and
     another was disposed of by the garbage collector.  (Bug #45699)

   * Adding the `Allow Batch=False' option to the connection string
     caused MySQL Connector/Net to generate the error:

          You have an error in your SQL syntax; check the manual that corresponds to your MySQL
                server version for the right syntax to use near 'SET character_set_results=NULL' at line 1

     (Bug #45502)

   * The MySQL Connector/Net 6.0.4 installer failed with an error. The
     error message generated was:

                  There is a problem with this Windows Installer package. A DLL required for this
                  install to complete could not be run. Contact your support personnel or package vendor.

     When `OK' was clicked to acknowledge the error the installer
     exited.  (Bug #45474)

   * A MySQL Connector/Net test program that connected to MySQL Server
     using the connection string option `compress=true' crashed, but
     only when running on Mono. The program worked as expected when
     running on Microsoft Windows.

     This was due to a bug in Mono. MySQL Connector/Net was modified to
     avoid using `WeakReferences' in the `Compressed' stream class,
     which was causing the crash.  (Bug #45463)

   * Calling the Entity Framework `SaveChanges()' method of any MySQL
     ORM Entity with a column type `TIME', generated an error message:

          Unknown PrimitiveKind Time

     (Bug #45457)

   * Insert into two tables failed when using the Entity Framework.
     The exception generated was:

                  The value given is not an instance of type 'Edm.Int32'

     (Bug #45077)

   * Input parameters were missing from Stored Procedures when using
     them with ADO.NET Data Entities.  (Bug #44985)

   * Errors occurred when using the Entity Framework with cultures that
     used a comma as the decimal separator. This was because the
     formatting for `SINGLE', `DOUBLE' and `DECIMAL' values was not
     handled correctly.  (Bug #44455)

   * When attempting to connect to MySQL using the Compact Framework
     version of MySQL Connector/Net, an `IndexOutOfRangeException'
     exception was generated on trying to open the connection.  (Bug
     #43736)

   * When reading data, such as with a `MySqlDataAdapter' on a
     `MySqlConnection', MySQL Connector/Net could potentially enter an
     infinite loop in `CompressedStream.ReadNextpacket()' if
     compression was enabled.  (Bug #43678)

   * An error occurred when building MySQL Connector/Net from source
     code checked out from the public SVN repository. This happened on
     Linux using Mono and Nant. The Mono JIT compiler version was
     1.2.6.0. The Nant version was 0.85.

     When an attempt was made to build (for example) the MySQL
     Connector/Net 5.2 branch using the command:

                  $ nant -buildfile:Client.build

     The following error occurred:

                  BUILD FAILED

                  Error loading buildfile.
                  Encoding name 'Windows-1252' not supported.
                  Parameter name: name

     (Bug #42411)

   * After a Reference to "C:\Program Files\MySQL\MySQL Connector Net
     5.2.4\Compact Framework\MySql.Data.CF.dll" was added to a Windows
     Mobile 5.0 project, the project then failed to build, generating a
     Microsoft Visual C# compiler error.

     The error generated was:

          Error 2 The type 'System.Runtime.CompilerServices.CompilerGeneratedAttribute'
                has no constructors defined MysqlTest
                Error 3 Internal Compiler Error (0xc0000005 at address 5A7E3714):
                likely culprit is 'COMPILE'.

     (Bug #42261)

   * MySQL Connector/Net CHM documentation stated that MySQL Server
     3.23 was supported.  (Bug #42110)

   * In the case of long network inactivity, especially when connection
     pooling was used, connections were sometimes dropped, for example,
     by firewalls.

     Note: The bugfix introduced a new `keepalive' parameter, which
     prevents disconnects by sending an empty TCP packet after a
     specified timeout.  (Bug #40684)

   * MySQL Connector/Net generated the following exception:

          System.NullReferenceException: Object reference not set to an instance of an object.
                bei MySql.Data.MySqlClient.MySqlCommand.TimeoutExpired(Object commandObject)
                bei System.Threading._TimerCallback.TimerCallback_Context(Object state)
                bei System.Threading.ExecutionContext.runTryCode(Object userData)
                bei
                System.Runtime.CompilerServices.RuntimeHelpers.ExecuteCodeWithGuaranteedCleanup(TryCode
                code, CleanupCode backoutCode, Object userData)
                bei System.Threading.ExecutionContext.RunInternal(ExecutionContext executionContext,
                ContextCallback callback, Object state)
                bei System.Threading.ExecutionContext.Run(ExecutionContext executionContext,
                ContextCallback callback, Object state)
                bei System.Threading._TimerCallback.PerformTimerCallback(Object state)

     (Bug #40005)

   * Calling a Stored Procedure with an output parameter through MySQL
     Connector/Net resulted in a memory leak. Calling the same Stored
     Procedure without an output parameter did not result in a memory
     leak.  (Bug #36027)

   * Using a `DataAdapter' with a linked `MySqlCommandBuilder' the
     following exception was thrown when trying to call
     `da.Update(DataRow[] rows)':

          Connection must be valid and open

     (Bug #34657)


File: manual.info,  Node: connector-net-news-6-0-4,  Next: connector-net-news-6-0-3,  Prev: connector-net-news-6-0-5,  Up: connector-net-news-6-0-x

D.4.5.5 Changes in MySQL Connector/Net 6.0.4 (16 June 2009)
...........................................................

This is the first post-GA release, fixing recently discovered bugs.

*Bugs Fixed*

   * If a certain socket exception occurred when trying to establish a
     MySQL database connection, MySQL Connector/Net displayed an
     exception message that appeared to be unrelated to the underlying
     problem.  This masked the problem and made diagnosing problems more
     difficult.

     For example, if, when establishing a database connection using
     TCP/IP, Windows on the local machine allocated an ephemeral port
     that conflicted with a socket address still in use, then
     Windows/.NET would throw a socket exception with the following
     error text:

          Only one usage of each socket address (protocol/network address/port) is normally
                permitted IP ADDRESS/PORT.

     However, MySQL Connector/Net masked this socket exception and
     displayed an exception with the following text:

          Unable to connect to any of the specified MySQL hosts.

     (Bug #45021)

   * A SQL query string containing an escaped backslash caused an
     exception to be generated:

          Index and length must refer to a location within the string.
                Parameter name: length
                at System.String.InternalSubStringWithChecks(Int32 startIndex, Int32 length, Boolean
                fAlwaysCopy)
                at MySql.Data.MySqlClient.MySqlTokenizer.NextParameter()
                at MySql.Data.MySqlClient.Statement.InternalBindParameters(String sql,
                MySqlParameterCollection parameters, MySqlPacket packet)
                at MySql.Data.MySqlClient.Statement.BindParameters()
                at MySql.Data.MySqlClient.PreparableStatement.Execute()
                at MySql.Data.MySqlClient.MySqlCommand.ExecuteReader(CommandBehavior be‎havior)
                at MySql.Data.MySqlClient.MySqlCommand.ExecuteNonQuery()

     (Bug #44960)

   * The Microsoft Visual Studio solution file `MySQL-VS2005.sln' was
     invalid. Several projects could not be loaded and thus it was not
     possible to build MySQL Connector/Net from source.  (Bug #44822)

   * The Data Set editor generated an error when attempts were made to
     modify insert, update or delete commands:

          Error in WHERE clause near '@'.
                Unable to parse query text.

     (Bug #44512)

   * The DataReader in MySQL Connector/Net 6.0.3 considered a
     BINARY(16) field as a GUID with a length of 16.  (Bug #44507)

   * When creating a new DataSet the following error was generated:

          Failed to open a connection to database.
                Cannot load type with name 'MySQL.Data.VisualStudio.StoredProcedureColumnEnumerator'

     (Bug #44460)

   * The MySQL Connector/Net MySQLRoleProvider reported that there were
     no roles, even when roles existed.  (Bug #44414)

   * MySQL Connector/Net was missing the capability to validate the
     server's certificate when using encryption. This made it possible
     to conduct a man-in-the-middle attack against the connection, which
     defeated the security provided by SSL.  (Bug #38700)


File: manual.info,  Node: connector-net-news-6-0-3,  Next: connector-net-news-6-0-2,  Prev: connector-net-news-6-0-4,  Up: connector-net-news-6-0-x

D.4.5.6 Changes in MySQL Connector/Net 6.0.3 (28 April 2009)
............................................................

First GA release.

*Functionality Added or Changed*

   * The `MySqlTokenizer' failed to split fieldnames from values if
     they were not separated by a space. This also happened if the
     string contained certain characters. As a result
     `MySqlCommand.ExecuteNonQuery' raised an index out of range
     exception.

     The resulting errors are illustrated by the following examples.
     Note, the example statements do not have delimiting spaces around
     the `=' operator.

          INSERT INTO anytable SET Text='test--test';

     The tokenizer incorrectly interpreted the value as containing a
     comment.

          UPDATE anytable SET Project='123-456',Text='Can you explain this ?',Duration=15 WHERE
                ID=4711;'

     A `MySqlException' was generated, as the `?' in the value was
     interpreted by the tokenizer as a parameter sign. The error
     message generated was:

          Fatal error encountered during command execution.
                EXCEPTION: MySqlException - Parameter '?'' must be defined.

     (Bug #44318)

*Bugs Fixed*

   * `MySQL.Data' was not displayed as a Reference inside Microsoft
     Visual Studio 2008 Professional.

     When a new C# project was created in Microsoft Visual Studio 2008
     Professional, `MySQL.Data' was not displayed when `References',
     `Add Reference' was selected.  (Bug #44141)

   * Column types for `SchemaProvider' and `ISSchemaProvider' did not
     match.

     When the source code in `SchemaProvider.cs' and
     `ISSchemaProvider.cs' were compared it was apparent that they were
     not using the same column types. The base provider used SQL such
     as `SHOW CREATE TABLE', while `ISSchemaProvider' used the schema
     information tables. Column types used by the base class were
     `INT64' and the column types used by `ISSchemaProvider' were
     `UNSIGNED'.  (Bug #44123)


File: manual.info,  Node: connector-net-news-6-0-2,  Next: connector-net-news-6-0-1,  Prev: connector-net-news-6-0-3,  Up: connector-net-news-6-0-x

D.4.5.7 Changes in MySQL Connector/Net 6.0.2 (07 April 2009 beta)
.................................................................

This is a new development release, fixing recently discovered bugs.

*Bugs Fixed*

   * MySQL Connector/Net 6.0.1 did not load in Microsoft Visual Studio
     2008 and Visual Studio 2005 Pro.

     The following error message was generated:

          .NET Framework Data Provider for MySQL: The data provider object factory service was not
                found.

     (Bug #44064)


File: manual.info,  Node: connector-net-news-6-0-1,  Next: connector-net-news-6-0-0,  Prev: connector-net-news-6-0-2,  Up: connector-net-news-6-0-x

D.4.5.8 Changes in MySQL Connector/Net 6.0.1 (02 April 2009 beta)
.................................................................

This is a new Beta development release, fixing recently discovered bugs.

*Bugs Fixed*

   * An insert and update error was generated by the decimal data type
     in the Entity Framework, when a German collation was used.  (Bug
     #43574)

   * Generating an Entity Data Model (EDM) schema with a table
     containing columns with data types `MEDIUMTEXT' and `LONGTEXT'
     generated a runtime error message `Max value too long or too short
     for Int32'.  (Bug #43480)


File: manual.info,  Node: connector-net-news-6-0-0,  Prev: connector-net-news-6-0-1,  Up: connector-net-news-6-0-x

D.4.5.9 Changes in MySQL Connector/Net 6.0.0 (02 March 2009 alpha)
..................................................................

This is a new Alpha development release.

*Bugs Fixed*

   * A null reference exception was generated when
     `MySqlConnection.ClearPool(connection)' was called.  (Bug #42801)


File: manual.info,  Node: connector-net-news-5-3-x,  Next: connector-net-news-5-2-x,  Prev: connector-net-news-6-0-x,  Up: connector-net-news

D.4.6 Changes in MySQL Connector/Net Version 5.3.x
--------------------------------------------------

* Menu:

* connector-net-news-5-3-0::     Changes in MySQL Connector/Net 5.3.0 (Not released)


File: manual.info,  Node: connector-net-news-5-3-0,  Prev: connector-net-news-5-3-x,  Up: connector-net-news-5-3-x

D.4.6.1 Changes in MySQL Connector/Net 5.3.0 (Not released)
...........................................................

*Bugs Fixed*

   * The Web Provider did not work at all on a remote host, and did not
     create a database when using `autogenerateschema="true"'.  (Bug
     #39072)

   * The MySQL Connector/Net installer program ended prematurely
     without reporting the specific error.  (Bug #39019)

   * When called with an incorrect password the
     MembershipProvider.GetPassword() method threw a MySQLException
     instead of a MembershipPasswordException .  (Bug #38939)

   * Possible overflow in MySqlPacket.ReadLong().  (Bug #36997)

   * The TokenizeSql method was adding query overhead and causing high
     CPU utilization for larger queries.  (Bug #36836)


File: manual.info,  Node: connector-net-news-5-2-x,  Next: connector-net-news-5-1-x,  Prev: connector-net-news-5-3-x,  Up: connector-net-news

D.4.7 Changes in MySQL Connector/Net Version 5.2.x
--------------------------------------------------

* Menu:

* connector-net-news-5-2-8::     Changes in MySQL Connector/Net 5.2.8 (Not released)
* connector-net-news-5-2-7::     Changes in MySQL Connector/Net 5.2.7 (15 July 2009)
* connector-net-news-5-2-6::     Changes in MySQL Connector/Net 5.2.6 (28 April 2009)
* connector-net-news-5-2-5::     Changes in MySQL Connector/Net 5.2.5 (19 November 2008)
* connector-net-news-5-2-4::     Changes in MySQL Connector/Net 5.2.4 (13 November 2008)
* connector-net-news-5-2-3::     Changes in MySQL Connector/Net 5.2.3 (19 August 2008)
* connector-net-news-5-2-2::     Changes in MySQL Connector/Net 5.2.2 (12 May 2008)
* connector-net-news-5-2-1::     Changes in MySQL Connector/Net 5.2.1 (27 February 2008)
* connector-net-news-5-2-0::     Changes in MySQL Connector/Net 5.2.0 (11 February 2008)


File: manual.info,  Node: connector-net-news-5-2-8,  Next: connector-net-news-5-2-7,  Prev: connector-net-news-5-2-x,  Up: connector-net-news-5-2-x

D.4.7.1 Changes in MySQL Connector/Net 5.2.8 (Not released)
...........................................................

*Bugs Fixed*

   * If `MySqlConnection.GetSchema' was called for "Indexes" on a table
     named `b`a`d' as follows:

          DataTable schemaPrimaryKeys = connection.GetSchema(
            "Indexes",
            new string[] { null, schemaName, "b`a`d"});

     Then the following exception was generated:

          You have an error in your SQL syntax; check the manual that corresponds to
          your MySQL server version for the right syntax to use near 'a`d`' at line 1

     (Bug #48101)

   * When the connection string option `Connection Reset = True' was
     used, a connection reset used the previously used encoding for the
     subsequent authentication operation. This failed, for example, if
     UCS2 was used to read the last column before the reset.  (Bug
     #47153)

   * In the `MySqlDataReader' class the `GetSByte' function returned a
     `byte' value instead of an `sbyte' value.  (Bug #46620)

   * When trying to create stored procedures from an SQL script, a
     `MySqlException' was thrown when attempting to redefine the
     `DELIMITER':

                  MySql.Data.MySqlClient.MySqlException was unhandled
                  Message="You have an error in your SQL syntax; check the manual that corresponds to your
                  MySQL server version for the right syntax to use near 'DELIMITER' at line 1"
                  Source="MySql.Data"
                  ErrorCode=-2147467259
                  Number=1064
                  StackTrace:
                  a` MySql.Data.MySqlClient.MySqlStream.ReadPacket()
                  a` MySql.Data.MySqlClient.NativeDriver.ReadResult(UInt64& affectedRows, Int64&
                  lastInsertId)
                  a` MySql.Data.MySqlClient.MySqlDataReader.GetResultSet()
                  a` MySql.Data.MySqlClient.MySqlDataReader.NextResult()
                  a` MySql.Data.MySqlClient.MySqlCommand.ExecuteReader(CommandBehavior behavior)
                  a` MySql.Data.MySqlClient.MySqlCommand.ExecuteReader()
                  a` MySql.Data.MySqlClient.MySqlCommand.ExecuteNonQuery()
                a` MySql.Data.MySqlClient.MySqlScript.Execute()

     Note: The `MySqlScript' class has been fixed to support the
     delimiter statement as it is found in SQL scripts.  (Bug #46429)

   * The MySQL Connector/Net Profile Provider,
     `MySql.Web.Profile.MySQLProfileProvider', generated an error when
     running on Mono. When an attempt was made to save a string in
     `Profile.Name' the string was not saved to the
     `my_aspnet_Profiles' table. If an attempt was made to force the
     save with `Profile.Save()' the following error was generated:

                  Server Error in '/mono' Application

                  --------------------------------------------------------------------------------

                  The requested feature is not implemented.
                  Description: HTTP 500. Error processing request.

                  Stack Trace:

                  System.NotImplementedException: The requested feature is not implemented.
                  at MySql.Data.MySqlClient.MySqlConnection.EnlistTransaction
                  (System.Transactions.Transaction transaction) [0x00000]
                  at MySql.Data.MySqlClient.MySqlConnection.Open () [0x00000]
                  at MySql.Web.Profile.MySQLProfileProvider.SetPropertyValues
                  (System.Configuration.SettingsContext context,
                  System.Configuration.SettingsPropertyValueCollection collection) [0x00000]

                  --------------------------------------------------------------------------------
                  Version information: Mono Version: 2.0.50727.1433; ASP.NET Version: 2.0.50727.1433

     (Bug #46375)

   * When using MySQL Connector/Net 6.0.4 and a MySQL Server 4.1 an
     exception was generated when trying to execute:

                  connection.GetSchema("Columns", ...);

     The exception generated was:

                  'connection.GetSchema("Columns")' threw an exception of type
                  'System.ArgumentException'System.Data.DataTable {System.ArgumentException}
                  base{"Input string was not in a correct format.Couldn't store <'Select'> in
                  NUMERIC_PRECISION Column.  Expected type is UInt64."}System.Exception
                  {System.ArgumentException}

     (Bug #46270)

   * The MySQL Connector/Net method
     `StoredProcedure.GetParameters(string)' ignored the programmer's
     setting of the `UseProcedureBodies' option. This broke any
     application for which the application's parameter names did not
     match the parameter names in the Stored Procedure, resulting in an
     `ArgumentException' with the message `Parameter 'foo' not found in
     the collection.' and the following stack trace:

                  MySql.Data.dll!MySql.Data.MySqlClient.MySqlParameterCollection.GetParameterFlexible(stri
                  ng parameterName = "pStart", bool throwOnNotFound = true) Line 459C#
                  MySql.Data.dll!MySql.Data.MySqlClient.StoredProcedure.Resolve() Line 157 + 0x25
                  bytesC#
                  MySql.Data.dll!MySql.Data.MySqlClient.MySqlCommand.ExecuteReader(System.Data.CommandBeha
                  vior behavior = SequentialAccess) Line 405 + 0xb bytesC#
                  MySql.Data.dll!MySql.Data.MySqlClient.MySqlCommand.ExecuteDbDataReader(System.Data.Comma
                  ndBehavior behavior = SequentialAccess) Line 884 + 0xb bytesC#
                  System.Data.dll!System.Data.Common.DbCommand.System.Data.IDbCommand.ExecuteReader(System
                  .Data.CommandBehavior behavior) + 0xb bytes
                  System.Data.dll!System.Data.Common.DbDataAdapter.FillInternal(System.Data.DataSet
                  dataset = {System.Data.DataSet}, System.Data.DataTable[] datatables = null, int
                  startRecord = 0, int maxRecords = 0, string srcTable = "Table", System.Data.IDbCommand
                  command = {MySql.Data.MySqlClient.MySqlCommand}, System.Data.CommandBehavior behavior) +
                  0x83 bytes
                  System.Data.dll!System.Data.Common.DbDataAdapter.Fill(System.Data.DataSet dataSet, int
                  startRecord, int maxRecords, string srcTable, System.Data.IDbCommand command,
                  System.Data.CommandBehavior behavior) + 0x120 bytes
                  System.Data.dll!System.Data.Common.DbDataAdapter.Fill(System.Data.DataSet dataSet) +
                  0x5f bytes

     (Bug #46213)

   * Conversion of MySQL `TINYINT(1)' to `boolean' failed.  (Bug
     #46205, Bug #46359, Bug #41953)

   * If the application slept for longer than the specified
     `net_write_timeout', and then resumed `Read' operations on a
     connection, then the application failed silently.  (Bug #45978)

   * When reading data, such as with a `MySqlDataAdapter' on a
     `MySqlConnection', MySQL Connector/Net could potentially enter an
     infinite loop in `CompressedStream.ReadNextpacket()' if
     compression was enabled.  (Bug #43678)

   * An error occurred when building MySQL Connector/Net from source
     code checked out from the public SVN repository. This happened on
     Linux using Mono and Nant. The Mono JIT compiler version was
     1.2.6.0. The Nant version was 0.85.

     When an attempt was made to build (for example) the MySQL
     Connector/Net 5.2 branch using the command:

                  $ nant -buildfile:Client.build

     The following error occurred:

                  BUILD FAILED

                  Error loading buildfile.
                  Encoding name 'Windows-1252' not supported.
                  Parameter name: name

     (Bug #42411)

   * MySQL Connector/Net CHM documentation stated that MySQL Server
     3.23 was supported.  (Bug #42110)

   * Using a `DataAdapter' with a linked `MySqlCommandBuilder' the
     following exception was thrown when trying to call
     `da.Update(DataRow[] rows)':

          Connection must be valid and open

     (Bug #34657)


File: manual.info,  Node: connector-net-news-5-2-7,  Next: connector-net-news-5-2-6,  Prev: connector-net-news-5-2-8,  Up: connector-net-news-5-2-x

D.4.7.2 Changes in MySQL Connector/Net 5.2.7 (15 July 2009)
...........................................................

*Bugs Fixed*

   * The `EscapeString' code carried out escaping by calling
     `string.Replace' multiple times. This resulted in a performance
     bottleneck, as for every line a new string was allocated and
     another was disposed of by the garbage collector.  (Bug #45699)

   * A MySQL Connector/Net test program that connected to MySQL Server
     using the connection string option `compress=true' crashed, but
     only when running on Mono. The program worked as expected when
     running on Microsoft Windows.

     This was due to a bug in Mono. MySQL Connector/Net was modified to
     avoid using `WeakReferences' in the `Compressed' stream class,
     which was causing the crash.  (Bug #45463)

   * If a certain socket exception occurred when trying to establish a
     MySQL database connection, MySQL Connector/Net displayed an
     exception message that appeared to be unrelated to the underlying
     problem.  This masked the problem and made diagnosing problems more
     difficult.

     For example, if, when establishing a database connection using
     TCP/IP, Windows on the local machine allocated an ephemeral port
     that conflicted with a socket address still in use, then
     Windows/.NET would throw a socket exception with the following
     error text:

          Only one usage of each socket address (protocol/network address/port) is normally
                permitted IP ADDRESS/PORT.

     However, MySQL Connector/Net masked this socket exception and
     displayed an exception with the following text:

          Unable to connect to any of the specified MySQL hosts.

     (Bug #45021)

   * The Microsoft Visual Studio solution file `MySQL-VS2005.sln' was
     invalid. Several projects could not be loaded and thus it was not
     possible to build MySQL Connector/Net from source.  (Bug #44822)

   * The MySQL Connector/Net MySQLRoleProvider reported that there were
     no roles, even when roles existed.  (Bug #44414)

   * After a Reference to "C:\Program Files\MySQL\MySQL Connector Net
     5.2.4\Compact Framework\MySql.Data.CF.dll" was added to a Windows
     Mobile 5.0 project, the project then failed to build, generating a
     Microsoft Visual C# compiler error.

     The error generated was:

          Error 2 The type 'System.Runtime.CompilerServices.CompilerGeneratedAttribute'
                has no constructors defined MysqlTest
                Error 3 Internal Compiler Error (0xc0000005 at address 5A7E3714):
                likely culprit is 'COMPILE'.

     (Bug #42261)

   * MySQL Connector/Net generated the following exception:

          System.NullReferenceException: Object reference not set to an instance of an object.
                bei MySql.Data.MySqlClient.MySqlCommand.TimeoutExpired(Object commandObject)
                bei System.Threading._TimerCallback.TimerCallback_Context(Object state)
                bei System.Threading.ExecutionContext.runTryCode(Object userData)
                bei
                System.Runtime.CompilerServices.RuntimeHelpers.ExecuteCodeWithGuaranteedCleanup(TryCode
                code, CleanupCode backoutCode, Object userData)
                bei System.Threading.ExecutionContext.RunInternal(ExecutionContext executionContext,
                ContextCallback callback, Object state)
                bei System.Threading.ExecutionContext.Run(ExecutionContext executionContext,
                ContextCallback callback, Object state)
                bei System.Threading._TimerCallback.PerformTimerCallback(Object state)

     (Bug #40005)

   * When a TableAdapter was created on a DataSet, it was not possible
     to use a stored procedure with variables. The following error was
     generated:

          The method or operation is not implemented

     (Bug #39409)


File: manual.info,  Node: connector-net-news-5-2-6,  Next: connector-net-news-5-2-5,  Prev: connector-net-news-5-2-7,  Up: connector-net-news-5-2-x

D.4.7.3 Changes in MySQL Connector/Net 5.2.6 (28 April 2009)
............................................................

*Functionality Added or Changed*

   * A new connection string option has been added: `use affected
     rows'. When `true' the connection will report changed rows instead
     of found rows.  (Bug #44194)

*Bugs Fixed*

   * Calling `GetSchema()' on `Indexes' or `IndexColumns' failed where
     index or column names were restricted.

     In `SchemaProvider.cs', methods `GetIndexes()' and
     `GetIndexColumns()' passed their restrictions directly to
     `GetTables()'. This only worked if the restrictions were no more
     specific than `schemaName' and `tableName'.  If `IndexName' was
     given, this was passed to `GetTables()' where it was treated as
     `TableType'. As a result no tables were returned, unless the index
     name happened to be `BASE TABLE' or `VIEW'. This meant that both
     methods failed to return any rows.  (Bug #43991)

   * `GetSchema("MetaDataCollections")' should have returned a table
     with a column named `NumberOfRestrictions' not
     `NumberOfRestriction'.

     This can be confirmed by referencing the Microsoft Documentation
     (http://msdn.microsoft.com/en-us/library/system.data.common.dbmetadatacolumnnames.numberofrestrictions.aspx).
     (Bug #43990)

   * Requests sent to the MySQL Connector/Net role provider to remove a
     user from a role failed. The query log showed the query was
     correctly executed within a transaction which was immediately
     rolled back.  The rollback was caused by a missing call to the
     `Complete' method of the transaction.  (Bug #43553)

   * When using `MySqlBulkLoader.Load()', the text file is opened by
     `NativeDriver.SendFileToServer'. If it encountered a problem
     opening the file as a stream, an exception was generated and
     caught. An attempt to clean up resources was then made in the
     `finally{}' clause by calling `fs.Close()', but since the stream
     was never successfully opened, this was an attempt to execute a
     method of a null reference.  (Bug #43332)

   * A null reference exception was generated when
     `MySqlConnection.ClearPool(connection)' was called.  (Bug #42801)

   * `MySQLMembershipProvider.ValidateUser' only used the `userId' to
     validate. However, it should also use the `applicationId' to
     perform the validation correctly.

     The generated query was, for example:

          SELECT Password, PasswordKey, PasswordFormat, IsApproved, Islockedout
                FROM my_aspnet_Membership WHERE userId=13

     Note that `applicationId' is not used.  (Bug #42574)

   * There was an error in the `ProfileProvider' class in the `private
     ProfileInfoCollection GetProfiles()' function. The column of the
     final table was named `lastUpdatdDate' ('e' is missing) instead of
     the correct `lastUpdatedDate'.  (Bug #41654)

   * The GetGuid() method of MySqlDataReader did not treat `BINARY(16)'
     column data as a GUID. When operating on such a column a
     `FormatException' exception was generated.  (Bug #41452)

   * When ASP.NET membership was configured to not require password
     question and answer using `requiresQuestionAndAnswer="false"', a
     `SqlNullValueException' was generated when using
     `MembershipUser.ResetPassword()' to reset the user password.  (Bug
     #41408)

   * If a `Stored Procedure' contained spaces in its parameter list,
     and was then called from MySQL Connector/Net, an exception was
     generated. However, the same `Stored Procedure' called from the
     MySQL Query Analyzer or the MySQL Client worked correctly.

     The exception generated was:

                  Parameter '0' not found in the collection.

     (Bug #41034)

   * The `DATETIME' format contained an erroneous space.  (Bug #41021)

   * When `MySql.Web.Profile.MySQLProfileProvider' was configured, it
     was not possible to assign a name other than the default name
     `MySQLProfileProvider'.

     If the name `SCC_MySQLProfileProvider' was assigned, an exception
     was generated when attempting to use `Page.Context.Profile['custom
     prop']'.

     The exception generated was:

          The profile default provider was not found.

     Note that the exception stated: 'the profile *default
     provider*...', even though a different name was explicitly
     requested.  (Bug #40871)

   * When `ExecuteNonQuery' was called with a command type of `Stored
     Procedure' it worked for one user but resulted in a hang for
     another user with the same database permissions.

     However, if *Note `CALL': call. was used in the command text and
     `ExecuteNonQuery' was used with a command type of `Text', the call
     worked for both users.  (Bug #40139)


File: manual.info,  Node: connector-net-news-5-2-5,  Next: connector-net-news-5-2-4,  Prev: connector-net-news-5-2-6,  Up: connector-net-news-5-2-x

D.4.7.4 Changes in MySQL Connector/Net 5.2.5 (19 November 2008)
...............................................................

*Bugs Fixed*

   * Visual Studio 2008 displayed the following error three times on
     start-up:

                  "Package Load Failure

                  Package 'MySql.Data.VisualStudio.MySqlDataProviderPackage, MySql.VisualStudio,
                  Version=5.2.4, Culture=neutral, PublicKeyToken=null' has failed to load properly (GUID =
                  {79A115C9-B133-4891-9E7B-242509DAD272}).  Please contact the package vendor for
                  assistance.  Application restart is recommended, due to possible environment corruption.
                  Would you like to disable loading the package in the future?  You may use
                  'devenve/resetskippkgs' to re-enable package loading."

     (Bug #40726)


File: manual.info,  Node: connector-net-news-5-2-4,  Next: connector-net-news-5-2-3,  Prev: connector-net-news-5-2-5,  Up: connector-net-news-5-2-x

D.4.7.5 Changes in MySQL Connector/Net 5.2.4 (13 November 2008)
...............................................................

*Bugs Fixed*

   * `MySqlDataReader' did not feature a `GetSByte' method.  (Bug
     #40571)

   * When working with stored procedures MySQL Connector/Net generated
     an exception `Unknown "table parameters" in information_schema'.
     (Bug #40382)

   * `GetDefaultCollation' and `GetMaxLength' were not thread safe.
     These functions called the database to get a set of parameters and
     cached them in two static dictionaries in the function
     `InitCollections'. However, if many threads called them they would
     try to insert the same keys in the collections resulting in
     duplicate key exceptions.  (Bug #40231)

   * If connection pooling was not set explicitly in the connection
     string, MySQL Connector/Net added `;Pooling=False' to the end of
     the connection string when `MySqlCommand.ExecuteReader()' was
     called.

     If connection pooling was explicitly set in the connection string,
     when `MySqlConnection.Open()' was called it converted
     `Pooling=True' to `pooling=True'.

     If `MySqlCommand.ExecuteReader()' was subsequently called, it
     concatenated `;Pooling=False' to the end of the connection string.
     The resulting connection string was thus terminated with
     `pooling=True;Pooling=False'. This disabled connection pooling
     completely.  (Bug #40091)

   * The connection string option `Functions Return String' did not set
     the correct encoding for the result string. Even though the
     connection string option `Functions Return String=true;' is set,
     the result of `SELECT DES_DECRYPT()' contained `??' instead of the
     correct national character symbols.  (Bug #40076)

   * If, when using the MySqlTransaction transaction object, an
     exception was thrown, the transaction object was not disposed of
     and the transaction was not rolled back.  (Bug #39817)

   * After the `ConnectionString' property was initialized using the
     public setter of DbConnectionStringBuilder, the
     GetConnectionString method of MySqlConnectionStringBuilder
     incorrectly returned `null' when `true' was assigned to the
     `includePass' parameter.  (Bug #39728)

   * When using ProfileProvider, attempting to update a previously
     saved property failed.  (Bug #39330)

   * Reading a negative time value greater than -01:00:00 returned the
     absolute value of the original time value.  (Bug #39294)

   * Inserting a negative time value (negative `TimeSpan') into a `Time'
     column through the use of MySqlParameter caused MySqlException to
     be thrown.  (Bug #39275)

   * When a data connection was created in the server explorer of
     Visual Studio 2008 Team, an error was generated when trying to
     expand stored procedures that had parameters.

     Also, if `TableAdapter' was right-clicked and then `Add', `Query',
     `Use Existing Stored Procedures' selected, if you then attempted
     to select a stored procedure, the window would close and no error
     message would be displayed.  (Bug #39252)

   * The Web Provider did not work at all on a remote host, and did not
     create a database when using `autogenerateschema="true"'.  (Bug
     #39072)

   * MySQL Connector/Net called hashed password methods not supported
     in Mono 2.0 Preview 2.  (Bug #38895)


File: manual.info,  Node: connector-net-news-5-2-3,  Next: connector-net-news-5-2-2,  Prev: connector-net-news-5-2-4,  Up: connector-net-news-5-2-x

D.4.7.6 Changes in MySQL Connector/Net 5.2.3 (19 August 2008)
.............................................................

*Functionality Added or Changed*

   * Error string was returned after a 28000 second `wait_timeout'.
     This has been changed to generate a `ConnectionState.Closed' event.
     (Bug #38119)

   * Changed how the procedure schema collection is retrieved. If `use
     procedure bodies=true' then the `mysql.proc' table is selected
     directly as this is up to 50 times faster than the current
     `information_schema' implementation. If `use procedure
     bodies=false', then the `information_schema' collection is queried.
     (Bug #36694)

   * String escaping functionality has been moved from the MySqlString
     class to the MySqlHelper class, where it can be accessed by the
     EscapeString method.  (Bug #36205)

*Bugs Fixed*

   * The GetOrdinal() method failed to return the ordinal if the column
     name string contained an accent.  (Bug #38721)

   * MySQL Connector/Net uninstaller did not clean up all installed
     files.  (Bug #38534)

   * There was a short circuit evaluation error in the
     MySqlCommand.CheckState() method. When the statement `connection
     == null' was true a NullReferenceException was thrown and not the
     expected InvalidOperationException.  (Bug #38276)

   * The provider did not silently create the user if the user did not
     exist.  (Bug #38243)

   * Executing a command that resulted in a fatal exception did not
     close the connection.  (Bug #37991)

   * When a prepared insert query is run that contains an `UNSIGNED
     TINYINT' in the parameter list, the complete query and data that
     should be inserted is corrupted and no error is thrown.  (Bug
     #37968)

   * In a .NET application MySQL Connector/Net modifies the connection
     string so that it contains several occurrences of the same option
     with different values. This is illustrated by the example that
     follows.

     The original connection string:

                  host=localhost;database=test;uid=*****;pwd=*****;
                connect timeout=25; auto enlist=false;pooling=false;

     The connection string after closing MySqlDataReader:

                  host=localhost;database=test;uid=*****;pwd=*****;
                  connect timeout=25;auto enlist=false;pooling=false;
                  Allow User Variables=True;Allow User Variables=False;
                Allow User Variables=True;Allow User Variables=False;

     (Bug #37955)

   * Unnecessary network traffic was generated for the normal case
     where the web provider schema was up to date.  (Bug #37469)

   * MySqlReader.GetOrdinal() performance enhancements break existing
     functionality.  (Bug #37239)

   * The `autogenerateschema' option produced tables with incorrect
     collations.  (Bug #36444)

   * GetSchema did not work correctly when querying for a collection,
     if using a non-English locale.  (Bug #35459)

   * When reading back a stored double or single value using the .NET
     provider, the value had less precision than the one stored.  (Bug
     #33322)

   * Using the MySQL Visual Studio plugin and a MySQL 4.1 server,
     certain field types (*Note `ENUM': enum.) would not be identified
     correctly. Also, when looking for tables, the plugin would list
     all tables matching a wildcard pattern of the database name
     supplied in the connection string, instead of only tables within
     the specified database.  (Bug #30603)


File: manual.info,  Node: connector-net-news-5-2-2,  Next: connector-net-news-5-2-1,  Prev: connector-net-news-5-2-3,  Up: connector-net-news-5-2-x

D.4.7.7 Changes in MySQL Connector/Net 5.2.2 (12 May 2008)
..........................................................

*Bugs Fixed*

   * Product documentation incorrectly stated '?' is the preferred
     parameter marker.  (Bug #37349)

   * An incorrect value for a bit field would returned in a multi-row
     query if a preceding value for the field returned `NULL'.  (Bug
     #36313)

   * Tables with `GEOMETRY' field types would return an unknown data
     type exception.  (Bug #36081)

   * When using the `MySQLProfileProvider', setting profile details and
     then reading back saved data would result in the default values
     being returned instead of the updated values.  (Bug #36000)

   * When creating a connection, setting the `ConnectionString'
     property of `MySqlConnection' to `NULL' would throw an exception.
     (Bug #35619)

   * The DbCommandBuilder.QuoteIdentifer method was not implemented.
     (Bug #35492)

   * When using encrypted passwords, the `GetPassword()' function would
     return the wrong string.  (Bug #35336)

   * An error would be raised when calling `GetPassword()' with a `NULL'
     value.  (Bug #35332)

   * When retrieving data where a field has been identified as
     containing a GUID value, the incorrect value would be returned
     when a previous row contained a `NULL' value for that field.  (Bug
     #35041)

   * Using the `TableAdapter Wizard' would fail when generating
     commands that used stored procedures due to the change in
     supported parameter characters.  (Bug #34941)

   * When creating a new stored procedures, the new parameter code
     which permits the use of the `@' symbol would interfere with the
     specification of a `DEFINER'.  (Bug #34940)

   * When using `SqlDataSource' to open a connection, the connection
     would not automatically be closed when access had completed.  (Bug
     #34460)

   * There was a high level of contention in the connection pooling
     code that could lead to delays when opening connections and
     submitting queries. The connection pooling code has been modified
     to try and limit the effects of the contention issue.  (Bug #34001)

   * Using the `TableAdaptor' wizard in combination with a suitable
     *Note `SELECT': select. statement, only the associated *Note
     `INSERT': insert.  statement would also be created, rather than
     the required *Note `DELETE': delete. and *Note `UPDATE': update.
     statements.  (Bug #31338)

   * Fixed problem in datagrid code related to creating a new table.
     This problem may have been introduced with .NET 2.0 SP1.

   * Fixed profile provider that would throw an exception if you were
     updating a profile that already existed.


File: manual.info,  Node: connector-net-news-5-2-1,  Next: connector-net-news-5-2-0,  Prev: connector-net-news-5-2-2,  Up: connector-net-news-5-2-x

D.4.7.8 Changes in MySQL Connector/Net 5.2.1 (27 February 2008)
...............................................................

*Bugs Fixed*

   * When using the provider to generate or update users and passwords,
     the password checking algorithm would not validate the password
     strength or requirements correctly.  (Bug #34792)

   * When executing statements that used stored procedures and
     functions, the new parameter code could fail to identify the
     correct parameter format.  (Bug #34699)

   * The installer would fail to the DDEX provider binary if the Visual
     Studio 2005 component was not selected. The result would lead to
     MySQL Connector/Net not loading properly when using the interface
     to a MySQL server within Visual Studio.  (Bug #34674)

   * A number of issues were identified in the case, connection and
     schema areas of the code for `MembershipProvider', `RoleProvider',
     `ProfileProvider'.  (Bug #34495)

   * When using web providers, the MySQL Connector/Net would check the
     schema and cache the application id, even when the connection
     string had been set. The effect would be to break the membership
     provider list.  (Bug #34451)

   * Attempting to use an isolation level other than the default with a
     transaction scope would use the default isolation level.  (Bug
     #34448)

   * When altering a stored procedure within Visual Studio, the
     parameters to the procedure could be lost.  (Bug #34359)

   * A race condition could occur within the procedure cache resulting
     the cache contents overflowing beyond the configured cache size.
     (Bug #34338)

   * Fixed problem with Visual Studio 2008 integration that caused
     pop-up menus on server explorer nodes to not function

   * The provider code has been updated to fix a number of outstanding
     issues.


File: manual.info,  Node: connector-net-news-5-2-0,  Prev: connector-net-news-5-2-1,  Up: connector-net-news-5-2-x

D.4.7.9 Changes in MySQL Connector/Net 5.2.0 (11 February 2008)
...............................................................

*Functionality Added or Changed*

   * Performing `GetValue()' on a field `TINYINT(1)' returned a *Note
     `BOOLEAN': numeric-types. While not a bug, this caused problems in
     software that expected an *Note `INT': numeric-types. to be
     returned. A new connection string option `Treat Tiny As Boolean'
     has been added with a default value of `true'. If set to `false'
     the provider will treat `TINYINT(1)' as *Note `INT': numeric-types.
     (Bug #34052)

   * Added support for `DbDataAdapter' `UpdateBatchSize'. Batching is
     fully supported including collapsing inserts down into the
     multi-value form if possible.

   * DDEX provider now works under Visual Studio 2008 beta 2.

   * Added ClearPool and ClearAllPools features.

*Bugs Fixed*

   * Some speed improvements have been implemented in the `TokenizeSql'
     process used to identify elements of SQL statements.  (Bug #34220)

   * When accessing tables from different databases within the same
     `TransactionScope', the same user/password combination would be
     used for each database connection. MySQL Connector/Net does not
     handle multiple connections within the same transaction scope. An
     error is now returned if you attempt this process, instead of
     using the incorrect authorization information.  (Bug #34204)

   * The status of connections reported through the state change
     handler was not being updated correctly.  (Bug #34082)

   * Incorporated some connection string cache optimizations sent to us
     by Maxim Mass.  (Bug #34000)

   * In an open connection where the server had disconnected
     unexpectedly, the status information of the connection would not
     be updated properly.  (Bug #33909)

   * Data cached from the connection string could return invalid
     information because the internal routines were not using
     case-sensitive semantics. This lead to updated connection string
     options not being recognized if they were of a different case than
     the existing cached values.  (Bug #31433)

   * Column name metadata was not using the character set as defined
     within the connection string being used.  (Bug #31185)

   * Memory usage could increase and decrease significantly when
     updating or inserting a large number of rows.  (Bug #31090)

   * Commands executed from within the state change handeler would fail
     with a `NULL' exception.  (Bug #30964)

   * When running a stored procedure multiple times on the same
     connection, the memory usage could increase indefinitely.  (Bug
     #30116)

   * Using compression in the MySQL connection with MySQL Connector/Net
     would be slower than using native (uncompressed) communication.
     (Bug #27865)

   * The `MySqlDbType.Datetime' has been replaced with
     `MySqlDbType.DateTime'. The old format has been obsoleted.  (Bug
     #26344)


File: manual.info,  Node: connector-net-news-5-1-x,  Next: connector-net-news-5-0-x,  Prev: connector-net-news-5-2-x,  Up: connector-net-news

D.4.8 Changes in MySQL Connector/Net Version 5.1.x
--------------------------------------------------

* Menu:

* connector-net-news-5-1-8::     Changes in MySQL Connector/Net 5.1.8 (Not released)
* connector-net-news-5-1-7::     Changes in MySQL Connector/Net 5.1.7 (21 August 2008)
* connector-net-news-5-1-6::     Changes in MySQL Connector/Net 5.1.6 (12 May 2008)
* connector-net-news-5-1-5::     Changes in MySQL Connector/Net 5.1.5 (Not released)
* connector-net-news-5-1-4::     Changes in MySQL Connector/Net 5.1.4 (20 November 2007)
* connector-net-news-5-1-3::     Changes in MySQL Connector/Net 5.1.3 (21 September 2007 beta)
* connector-net-news-5-1-2::     Changes in MySQL Connector/Net 5.1.2 (18 June 2007)
* connector-net-news-5-1-1::     Changes in MySQL Connector/Net 5.1.1 (23 May 2007)
* connector-net-news-5-1-0::     Changes in MySQL Connector/Net 5.1.0 (01 May 2007)


File: manual.info,  Node: connector-net-news-5-1-8,  Next: connector-net-news-5-1-7,  Prev: connector-net-news-5-1-x,  Up: connector-net-news-5-1-x

D.4.8.1 Changes in MySQL Connector/Net 5.1.8 (Not released)
...........................................................

*Bugs Fixed*

   * Calling `GetSchema()' on `Indexes' or `IndexColumns' failed where
     index or column names were restricted.

     In `SchemaProvider.cs', methods `GetIndexes()' and
     `GetIndexColumns()' passed their restrictions directly to
     `GetTables()'. This only worked if the restrictions were no more
     specific than `schemaName' and `tableName'.  If `IndexName' was
     given, this was passed to `GetTables()' where it was treated as
     `TableType'. As a result no tables were returned, unless the index
     name happened to be `BASE TABLE' or `VIEW'. This meant that both
     methods failed to return any rows.  (Bug #43991)

   * The `DATETIME' format contained an erroneous space.  (Bug #41021)

   * If connection pooling was not set explicitly in the connection
     string, MySQL Connector/Net added `;Pooling=False' to the end of
     the connection string when `MySqlCommand.ExecuteReader()' was
     called.

     If connection pooling was explicitly set in the connection string,
     when `MySqlConnection.Open()' was called it converted
     `Pooling=True' to `pooling=True'.

     If `MySqlCommand.ExecuteReader()' was subsequently called, it
     concatenated `;Pooling=False' to the end of the connection string.
     The resulting connection string was thus terminated with
     `pooling=True;Pooling=False'. This disabled connection pooling
     completely.  (Bug #40091)

   * MySQL Connector/Net generated the following exception:

          System.NullReferenceException: Object reference not set to an instance of an object.
                bei MySql.Data.MySqlClient.MySqlCommand.TimeoutExpired(Object commandObject)
                bei System.Threading._TimerCallback.TimerCallback_Context(Object state)
                bei System.Threading.ExecutionContext.runTryCode(Object userData)
                bei
                System.Runtime.CompilerServices.RuntimeHelpers.ExecuteCodeWithGuaranteedCleanup(TryCode
                code, CleanupCode backoutCode, Object userData)
                bei System.Threading.ExecutionContext.RunInternal(ExecutionContext executionContext,
                ContextCallback callback, Object state)
                bei System.Threading.ExecutionContext.Run(ExecutionContext executionContext,
                ContextCallback callback, Object state)
                bei System.Threading._TimerCallback.PerformTimerCallback(Object state)

     (Bug #40005)

   * If, when using the MySqlTransaction transaction object, an
     exception was thrown, the transaction object was not disposed of
     and the transaction was not rolled back.  (Bug #39817)

   * When a prepared insert query is run that contains an `UNSIGNED
     TINYINT' in the parameter list, the complete query and data that
     should be inserted is corrupted and no error is thrown.  (Bug
     #37968)

   * Calling `MySqlDataAdapter.FillSchema' on a `SELECT' statement that
     referred to a table that did not exist left the connection in a
     bad state. After this call, all `SELECT' statements returned an
     empty result set. If the `SELECT' statement referred to a table
     that did exist then everything worked as expected.  (Bug #30518)


File: manual.info,  Node: connector-net-news-5-1-7,  Next: connector-net-news-5-1-6,  Prev: connector-net-news-5-1-8,  Up: connector-net-news-5-1-x

D.4.8.2 Changes in MySQL Connector/Net 5.1.7 (21 August 2008)
.............................................................

*Bugs Fixed*

   * There was a short circuit evaluation error in the
     MySqlCommand.CheckState() method. When the statement `connection
     == null' was true a NullReferenceException was thrown and not the
     expected InvalidOperationException.  (Bug #38276)

   * Executing a command that resulted in a fatal exception did not
     close the connection.  (Bug #37991)

   * In a .NET application MySQL Connector/Net modifies the connection
     string so that it contains several occurrences of the same option
     with different values. This is illustrated by the example that
     follows.

     The original connection string:

                  host=localhost;database=test;uid=*****;pwd=*****;
                connect timeout=25; auto enlist=false;pooling=false;

     The connection string after closing MySqlDataReader:

                  host=localhost;database=test;uid=*****;pwd=*****;
                  connect timeout=25;auto enlist=false;pooling=false;
                  Allow User Variables=True;Allow User Variables=False;
                Allow User Variables=True;Allow User Variables=False;

     (Bug #37955)

   * As MySqlDbType.DateTime is not available in `VB.Net' the warning
     `The datetime enum value is obsolete' was always shown during
     compilation.  (Bug #37406)

   * An unknown `MySqlErrorCode' was encountered when opening a
     connection with an incorrect password.  (Bug #37398)

   * Documentation incorrectly stated that `the DataColumn class in
     .NET 1.0 and 1.1 does not permit columns with type of UInt16,
     UInt32, or UInt64 to be autoincrement columns'.  (Bug #37350)

   * SemaphoreFullException is generated when application is closed.
     (Bug #36688)

   * GetSchema did not work correctly when querying for a collection,
     if using a non-English locale.  (Bug #35459)

   * When reading back a stored double or single value using the .NET
     provider, the value had less precision than the one stored.  (Bug
     #33322)

   * Using the MySQL Visual Studio plugin and a MySQL 4.1 server,
     certain field types (*Note `ENUM': enum.) would not be identified
     correctly. Also, when looking for tables, the plugin would list
     all tables matching a wildcard pattern of the database name
     supplied in the connection string, instead of only tables within
     the specified database.  (Bug #30603)


File: manual.info,  Node: connector-net-news-5-1-6,  Next: connector-net-news-5-1-5,  Prev: connector-net-news-5-1-7,  Up: connector-net-news-5-1-x

D.4.8.3 Changes in MySQL Connector/Net 5.1.6 (12 May 2008)
..........................................................

*Bugs Fixed*

   * When creating a connection pool, specifying an invalid IP address
     will cause the entire application to crash, instead of providing
     an exception.  (Bug #36432)

   * An incorrect value for a bit field would returned in a multi-row
     query if a preceding value for the field returned `NULL'.  (Bug
     #36313)

   * The `MembershipProvider' will raise an exception when the
     connection string is configured with `enablePasswordRetrival =
     true' and `RequireQuestionAndAnswer = false'.  (Bug #36159)

   * When calling `GetNumberOfUsersOnline' an exception is raised on
     the submitted query due to a missing parameter.  (Bug #36157)

   * Tables with `GEOMETRY' field types would return an unknown data
     type exception.  (Bug #36081)

   * When creating a connection, setting the `ConnectionString'
     property of `MySqlConnection' to `NULL' would throw an exception.
     (Bug #35619)

   * The DbCommandBuilder.QuoteIdentifer method was not implemented.
     (Bug #35492)

   * When using `SqlDataSource' to open a connection, the connection
     would not automatically be closed when access had completed.  (Bug
     #34460)

   * Attempting to use an isolation level other than the default with a
     transaction scope would use the default isolation level.  (Bug
     #34448)

   * When altering a stored procedure within Visual Studio, the
     parameters to the procedure could be lost.  (Bug #34359)

   * A race condition could occur within the procedure cache resulting
     the cache contents overflowing beyond the configured cache size.
     (Bug #34338)

   * Using the `TableAdaptor' wizard in combination with a suitable
     *Note `SELECT': select. statement, only the associated *Note
     `INSERT': insert.  statement would also be created, rather than
     the required *Note `DELETE': delete. and *Note `UPDATE': update.
     statements.  (Bug #31338)


File: manual.info,  Node: connector-net-news-5-1-5,  Next: connector-net-news-5-1-4,  Prev: connector-net-news-5-1-6,  Up: connector-net-news-5-1-x

D.4.8.4 Changes in MySQL Connector/Net 5.1.5 (Not released)
...........................................................

*Functionality Added or Changed*

   * Performing `GetValue()' on a field `TINYINT(1)' returned a *Note
     `BOOLEAN': numeric-types. While not a bug, this caused problems in
     software that expected an *Note `INT': numeric-types. to be
     returned. A new connection string option `Treat Tiny As Boolean'
     has been added with a default value of `true'. If set to `false'
     the provider will treat `TINYINT(1)' as *Note `INT': numeric-types.
     (Bug #34052)

*Bugs Fixed*

   * Some speed improvements have been implemented in the `TokenizeSql'
     process used to identify elements of SQL statements.  (Bug #34220)

   * When accessing tables from different databases within the same
     `TransactionScope', the same user/password combination would be
     used for each database connection. MySQL Connector/Net does not
     handle multiple connections within the same transaction scope. An
     error is now returned if you attempt this process, instead of
     using the incorrect authorization information.  (Bug #34204)

   * The status of connections reported through the state change
     handler was not being updated correctly.  (Bug #34082)

   * Incorporated some connection string cache optimizations sent to us
     by Maxim Mass.  (Bug #34000)

   * In an open connection where the server had disconnected
     unexpectedly, the status information of the connection would not
     be updated properly.  (Bug #33909)

   * MySQL Connector/Net would fail to compile properly with `nant'.
     (Bug #33508)

   * Problem with membership provider would mean that `FindUserByEmail'
     would fail with a `MySqlException' because it was trying to add a
     second parameter with the same name as the first.  (Bug #33347)

   * Using compression in the MySQL connection with MySQL Connector/Net
     would be slower than using native (uncompressed) communication.
     (Bug #27865)


File: manual.info,  Node: connector-net-news-5-1-4,  Next: connector-net-news-5-1-3,  Prev: connector-net-news-5-1-5,  Up: connector-net-news-5-1-x

D.4.8.5 Changes in MySQL Connector/Net 5.1.4 (20 November 2007)
...............................................................

*Bugs Fixed*

   * Setting the size of a string parameter after the value could cause
     an exception.  (Bug #32094)

   * Creation of parameter objects with noninput direction using a
     constructor would fail. This was cause by some old legacy code
     preventing their use.  (Bug #32093)

   * A date string could be returned incorrectly by
     `MySqlDateTime.ToString()' when the date returned by MySQL was
     `0000-00-00 00:00:00'.  (Bug #32010)

   * A syntax error in a set of batch statements could leave the data
     adapter in a state that appears hung.  (Bug #31930)

   * Installing over a failed uninstall of a previous version could
     result in multiple clients being registered in the
     `machine.config'. This would prevent certain aspects of the MySQL
     connection within Visual Studio to work properly.  (Bug #31731)

   * MySQL Connector/Net would incorrectly report success when
     enlisting in a distributed transaction, although distributed
     transactions are not supported.  (Bug #31703)

   * Data cached from the connection string could return invalid
     information because the internal routines were not using
     case-sensitive semantics. This lead to updated connection string
     options not being recognized if they were of a different case than
     the existing cached values.  (Bug #31433)

   * Trying to use a connection that was not open could return an
     ambiguous and misleading error message.  (Bug #31262)

   * Column name metadata was not using the character set as defined
     within the connection string being used.  (Bug #31185)

   * Memory usage could increase and decrease significantly when
     updating or inserting a large number of rows.  (Bug #31090)

   * Commands executed from within the state change handeler would fail
     with a `NULL' exception.  (Bug #30964)

   * Extracting data through XML functions within a query returns the
     data as `System.Byte[]'. This was due to MySQL Connector/Net
     incorrectly identifying *Note `BLOB': blob.  fields as binary,
     rather than text.  (Bug #30233)

   * When running a stored procedure multiple times on the same
     connection, the memory usage could increase indefinitely.  (Bug
     #30116)

   * Column types with only 1-bit (such as *Note `BOOLEAN':
     numeric-types. and `TINYINT(1)' were not returned as boolean
     fields.  (Bug #27959)

   * When accessing certain statements, the command would timeout
     before the command completed. Because this cannot always be
     controlled through the individual command timeout options, a
     `default command timeout' has been added to the connection string
     options.  (Bug #27958)

   * The server error code was not updated in the `Data[]' hash, which
     prevented `DbProviderFactory' users from accessing the server
     error code.  (Bug #27436)

   * The `MySqlDbType.Datetime' has been replaced with
     `MySqlDbType.DateTime'. The old format has been obsoleted.  (Bug
     #26344)

   * Changing the connection string of a connection to one that changes
     the parameter marker after the connection had been assigned to a
     command but before the connection is opened could cause parameters
     to not be found.  (Bug #13991)


File: manual.info,  Node: connector-net-news-5-1-3,  Next: connector-net-news-5-1-2,  Prev: connector-net-news-5-1-4,  Up: connector-net-news-5-1-x

D.4.8.6 Changes in MySQL Connector/Net 5.1.3 (21 September 2007 beta)
.....................................................................

This is a new Beta development release, fixing recently discovered bugs.

*Bugs Fixed*

   * An incorrect `ConstraintException' could be raised on an *Note
     `INSERT': insert. when adding rows to a table with a
     multiple-column unique key index.  (Bug #30204)

   * A *Note `DATE': datetime. field would be updated with a date/time
     value, causing a `MySqlDataAdapter.Update()' exception.  (Bug
     #30077)

   * The Saudi Hijri calendar was not supported.  (Bug #29931)

   * Calling *Note `SHOW CREATE PROCEDURE': show-create-procedure. for
     routines with a hyphen in the catalog name produced a syntax error.
     (Bug #29526)

   * Connecting to a MySQL server earlier than version 4.1 would raise
     a `NullException'.  (Bug #29476)

   * The availability of a MySQL server would not be reset when using
     pooled connections (`pooling=true'). This would lead to the server
     being reported as unavailable, even if the server become available
     while the application was still running.  (Bug #29409)

   * A `FormatException' error would be raised if a parameter had not
     been found, instead of `Resources.ParameterMustBeDefined'.  (Bug
     #29312)

   * An exception would be thrown when using the Manage Role
     functionality within the web administrator to assign a role to a
     user.  (Bug #29236)

   * Using the membership/role providers when `validationKey' or
     `decryptionKey' parameters are set to `AutoGenerate', an exception
     would be raised when accessing the corresponding values.  (Bug
     #29235)

   * Certain operations would not check the `UsageAdvisor' setting,
     causing log messages from the Usage Advisor even when it was
     disabled.  (Bug #29124)

   * Using the same connection string multiple times would result in
     `Database=DBNAME' appearing multiple times in the resulting string.
     (Bug #29123)

   * _Visual Studio Plugin_: Adding a new query based on a stored
     procedure that uses the *Note `SELECT': select. statement would
     terminate the query/TableAdapter wizard.  (Bug #29098)

   * Using `TransactionScope' would cause an
     `InvalidOperationException'.  (Bug #28709)


File: manual.info,  Node: connector-net-news-5-1-2,  Next: connector-net-news-5-1-1,  Prev: connector-net-news-5-1-3,  Up: connector-net-news-5-1-x

D.4.8.7 Changes in MySQL Connector/Net 5.1.2 (18 June 2007)
...........................................................

This is a new Beta development release, fixing recently discovered bugs.

*Bugs Fixed*

   * Log messages would be truncated to 300 bytes.  (Bug #28706)

   * Creating a user would fail due to the application name being set
     incorrectly.  (Bug #28648)

   * _Visual Studio Plugin_: Adding a new query based on a stored
     procedure that used a *Note `UPDATE': update, *Note `INSERT':
     insert. or *Note `DELETE': delete. statement would terminate the
     query/TableAdapter wizard.  (Bug #28536)

   * _Visual Studio Plugin_: Query Builder would fail to show *Note
     `TINYTEXT': blob. columns, and any columns listed after a *Note
     `TINYTEXT': blob. column correctly.  (Bug #28437)

   * Accessing the results from a large query when using data
     compression in the connection would fail to return all the data.
     (Bug #28204)

   * _Visual Studio Plugin_: Update commands would not be generated
     correctly when using the TableAdapter wizard.  (Bug #26347)


File: manual.info,  Node: connector-net-news-5-1-1,  Next: connector-net-news-5-1-0,  Prev: connector-net-news-5-1-2,  Up: connector-net-news-5-1-x

D.4.8.8 Changes in MySQL Connector/Net 5.1.1 (23 May 2007)
..........................................................

*Bugs Fixed*

   * Running the statement *Note `SHOW PROCESSLIST': show-processlist.
     would return columns as byte arrays instead of native columns.
     (Bug #28448)

   * Installation of the MySQL Connector/Net on Windows would fail if
     VisualStudio had not already been installed.  (Bug #28260)

   * MySQL Connector/Net would look for the wrong table when executing
     `User.IsRole().' (Bug #28251)

   * Building a connection string within a tight loop would show slow
     performance.  (Bug #28167)

   * The `UNSIGNED' flag for parameters in a stored procedure would be
     ignored when using `MySqlCommandBuilder' to obtain the parameter
     information.  (Bug #27679)

   * Using `MySQLDataAdapter.FillSchema()' on a stored procedure would
     raise an exception: `Invalid attempt to access a field before
     calling Read()'.  (Bug #27668)

   * *Note `DATETIME': datetime. fields from versions of MySQL bgefore
     4.1 would be incorrectly parsed, resulting in a exception.  (Bug
     #23342)

   * Fixed password property on `MySqlConnectionStringBuilder' to use
     `PasswordPropertyText' attribute. This causes dots to show instead
     of actual password text.


File: manual.info,  Node: connector-net-news-5-1-0,  Prev: connector-net-news-5-1-1,  Up: connector-net-news-5-1-x

D.4.8.9 Changes in MySQL Connector/Net 5.1.0 (01 May 2007)
..........................................................

*Functionality Added or Changed*

   * Now compiles for .NET CF 2.0.

   * Rewrote stored procedure parsing code using a new SQL tokenizer.
     Really nasty procedures including nested comments are now
     supported.

   * GetSchema will now report objects relative to the currently
     selected database. What this means is that passing in null as a
     database restriction will report objects on the currently selected
     database only.

   * Added Membership and Role provider contributed by Sean Wright
     (thanks!).


File: manual.info,  Node: connector-net-news-5-0-x,  Next: connector-net-news-1-0-x,  Prev: connector-net-news-5-1-x,  Up: connector-net-news

D.4.9 Changes in MySQL Connector/Net Version 5.0.x
--------------------------------------------------

* Menu:

* connector-net-news-5-0-10::    Changes in MySQL Connector/Net 5.0.10 (Not released)
* connector-net-news-5-0-9::     Changes in MySQL Connector/Net 5.0.9 (Not released)
* connector-net-news-5-0-8::     Changes in MySQL Connector/Net 5.0.8 (21 August 2007)
* connector-net-news-5-0-7::     Changes in MySQL Connector/Net 5.0.7 (18 May 2007)
* connector-net-news-5-0-6::     Changes in MySQL Connector/Net 5.0.6 (22 March 2007)
* connector-net-news-5-0-5::     Changes in MySQL Connector/Net 5.0.5 (07 March 2007)
* connector-net-news-5-0-4::     Changes in MySQL Connector/Net 5.0.4 (Not released)
* connector-net-news-5-0-3::     Changes in MySQL Connector/Net 5.0.3 (05 January 2007)
* connector-net-news-5-0-2::     Changes in MySQL Connector/Net 5.0.2 (06 November 2006)
* connector-net-news-5-0-1::     Changes in MySQL Connector/Net 5.0.1 (01 October 2006)
* connector-net-news-5-0-0::     Changes in MySQL Connector/Net 5.0.0 (08 August 2006)


File: manual.info,  Node: connector-net-news-5-0-10,  Next: connector-net-news-5-0-9,  Prev: connector-net-news-5-0-x,  Up: connector-net-news-5-0-x

D.4.9.1 Changes in MySQL Connector/Net 5.0.10 (Not released)
............................................................

*Bugs Fixed*

   * If, when using the MySqlTransaction transaction object, an
     exception was thrown, the transaction object was not disposed of
     and the transaction was not rolled back.  (Bug #39817)

   * Executing a command that resulted in a fatal exception did not
     close the connection.  (Bug #37991)

   * When a prepared insert query is run that contains an `UNSIGNED
     TINYINT' in the parameter list, the complete query and data that
     should be inserted is corrupted and no error is thrown.  (Bug
     #37968)

   * In a .NET application MySQL Connector/Net modifies the connection
     string so that it contains several occurrences of the same option
     with different values. This is illustrated by the example that
     follows.

     The original connection string:

                  host=localhost;database=test;uid=*****;pwd=*****;
                connect timeout=25; auto enlist=false;pooling=false;

     The connection string after closing MySqlDataReader:

                  host=localhost;database=test;uid=*****;pwd=*****;
                  connect timeout=25;auto enlist=false;pooling=false;
                  Allow User Variables=True;Allow User Variables=False;
                Allow User Variables=True;Allow User Variables=False;

     (Bug #37955)

   * When creating a connection pool, specifying an invalid IP address
     will cause the entire application to crash, instead of providing
     an exception.  (Bug #36432)

   * GetSchema did not work correctly when querying for a collection,
     if using a non-English locale.  (Bug #35459)

   * When reading back a stored double or single value using the .NET
     provider, the value had less precision than the one stored.  (Bug
     #33322)


File: manual.info,  Node: connector-net-news-5-0-9,  Next: connector-net-news-5-0-8,  Prev: connector-net-news-5-0-10,  Up: connector-net-news-5-0-x

D.4.9.2 Changes in MySQL Connector/Net 5.0.9 (Not released)
...........................................................

*Bugs Fixed*

   * The DbCommandBuilder.QuoteIdentifer method was not implemented.
     (Bug #35492)

   * Setting the size of a string parameter after the value could cause
     an exception.  (Bug #32094)

   * Creation of parameter objects with noninput direction using a
     constructor would fail. This was cause by some old legacy code
     preventing their use.  (Bug #32093)

   * A date string could be returned incorrectly by
     `MySqlDateTime.ToString()' when the date returned by MySQL was
     `0000-00-00 00:00:00'.  (Bug #32010)

   * A syntax error in a set of batch statements could leave the data
     adapter in a state that appears hung.  (Bug #31930)

   * Installing over a failed uninstall of a previous version could
     result in multiple clients being registered in the
     `machine.config'. This would prevent certain aspects of the MySQL
     connection within Visual Studio to work properly.  (Bug #31731)

   * Data cached from the connection string could return invalid
     information because the internal routines were not using
     case-sensitive semantics. This lead to updated connection string
     options not being recognized if they were of a different case than
     the existing cached values.  (Bug #31433)

   * Column name metadata was not using the character set as defined
     within the connection string being used.  (Bug #31185)

   * Memory usage could increase and decrease significantly when
     updating or inserting a large number of rows.  (Bug #31090)

   * Commands executed from within the state change handeler would fail
     with a `NULL' exception.  (Bug #30964)

   * When running a stored procedure multiple times on the same
     connection, the memory usage could increase indefinitely.  (Bug
     #30116)

   * The server error code was not updated in the `Data[]' hash, which
     prevented `DbProviderFactory' users from accessing the server
     error code.  (Bug #27436)

   * Changing the connection string of a connection to one that changes
     the parameter marker after the connection had been assigned to a
     command but before the connection is opened could cause parameters
     to not be found.  (Bug #13991)


File: manual.info,  Node: connector-net-news-5-0-8,  Next: connector-net-news-5-0-7,  Prev: connector-net-news-5-0-9,  Up: connector-net-news-5-0-x

D.4.9.3 Changes in MySQL Connector/Net 5.0.8 (21 August 2007)
.............................................................

*Note*:

This version introduces a new installer technology.

*Bugs Fixed*

   * Extracting data through XML functions within a query returns the
     data as `System.Byte[]'. This was due to MySQL Connector/Net
     incorrectly identifying *Note `BLOB': blob.  fields as binary,
     rather than text.  (Bug #30233)

   * An incorrect `ConstraintException' could be raised on an *Note
     `INSERT': insert. when adding rows to a table with a
     multiple-column unique key index.  (Bug #30204)

   * A *Note `DATE': datetime. field would be updated with a date/time
     value, causing a `MySqlDataAdapter.Update()' exception.  (Bug
     #30077)

   * Fixed bug where MySQL Connector/Net was hand building some date
     time patterns rather than using the patterns provided under
     CultureInfo. This caused problems with some calendars that do not
     support the same ranges as Gregorian..  (Bug #29931)

   * Calling *Note `SHOW CREATE PROCEDURE': show-create-procedure. for
     routines with a hyphen in the catalog name produced a syntax error.
     (Bug #29526)

   * The availability of a MySQL server would not be reset when using
     pooled connections (`pooling=true'). This would lead to the server
     being reported as unavailable, even if the server become available
     while the application was still running.  (Bug #29409)

   * A `FormatException' error would be raised if a parameter had not
     been found, instead of `Resources.ParameterMustBeDefined'.  (Bug
     #29312)

   * Certain operations would not check the `UsageAdvisor' setting,
     causing log messages from the Usage Advisor even when it was
     disabled.  (Bug #29124)

   * Using the same connection string multiple times would result in
     `Database=DBNAME' appearing multiple times in the resulting string.
     (Bug #29123)

   * Log messages would be truncated to 300 bytes.  (Bug #28706)

   * Accessing the results from a large query when using data
     compression in the connection will fail to return all the data.
     (Bug #28204)

   * Fixed problem where `MySqlConnection.BeginTransaction' checked the
     drivers status var before checking if the connection was open.
     The result was that the driver could report an invalid condition
     on a previously opened connection.

   * Fixed problem where we were not closing prepared statement handles
     when commands are disposed. This could lead to using up all
     prepared statement handles on the server.

   * Fixed the database schema collection so that it works on servers
     that are not properly respecting the `lower_case_table_names'
     setting.

   * Fixed problem where any attempt to not read all the records
     returned from a select where each row of the select is greater
     than 1024 bytes would hang the driver.

   * Fixed problem where a command timing out just after it actually
     finished would cause an exception to be thrown on the command
     timeout thread which would then be seen as an unhandled exception.

   * Fixed some serious issues with command timeout and cancel that
     could present as exceptions about thread ownership. The issue was
     that not all queries cancel the same. Some produce resultsets
     while others don't. ExecuteReader had to be changed to check for
     this.


File: manual.info,  Node: connector-net-news-5-0-7,  Next: connector-net-news-5-0-6,  Prev: connector-net-news-5-0-8,  Up: connector-net-news-5-0-x

D.4.9.4 Changes in MySQL Connector/Net 5.0.7 (18 May 2007)
..........................................................

*Bugs Fixed*

   * Running the statement *Note `SHOW PROCESSLIST': show-processlist.
     would return columns as byte arrays instead of native columns.
     (Bug #28448)

   * Building a connection string within a tight loop would show slow
     performance.  (Bug #28167)

   * Using logging (with the `logging=true' parameter to the connection
     string) would not generate a log file.  (Bug #27765)

   * The `UNSIGNED' flag for parameters in a stored procedure would be
     ignored when using `MySqlCommandBuilder' to obtain the parameter
     information.  (Bug #27679)

   * Using `MySQLDataAdapter.FillSchema()' on a stored procedure would
     raise an exception: `Invalid attempt to access a field before
     calling Read()'.  (Bug #27668)

   * If you close an open connection with an active transaction, the
     transaction is not automatically rolled back.  (Bug #27289)

   * When cloning an open `MySqlClient.MySqlConnection' with the
     `Persist Security Info=False' option set, the cloned connection is
     not usable because the security information has not been cloned.
     (Bug #27269)

   * Enlisting a null transaction would affect the current connection
     object, such that further enlistment operations to the transaction
     are not possible.  (Bug #26754)

   * Attempting to change the `Connection Protocol' property within a
     `PropertyGrid' control would raise an exception.  (Bug #26472)

   * The `characterset' property would not be identified during a
     connection (also affected Visual Studion Plugin).  (Bug #26147,
     Bug #27240)

   * The `CreateFormat' column of the `DataTypes' collection did not
     contain a format specification for creating a new column type.
     (Bug #25947)

   * *Note `DATETIME': datetime. fields from versions of MySQL bgefore
     4.1 would be incorrectly parsed, resulting in a exception.  (Bug
     #23342)


File: manual.info,  Node: connector-net-news-5-0-6,  Next: connector-net-news-5-0-5,  Prev: connector-net-news-5-0-7,  Up: connector-net-news-5-0-x

D.4.9.5 Changes in MySQL Connector/Net 5.0.6 (22 March 2007)
............................................................

*Bugs Fixed*

   * Publisher listed in "Add/Remove Programs" is not consistent with
     other MySQL products.  (Bug #27253)

   * `DESCRIBE ....' SQL statement returns byte arrays rather than data
     on MySQL versions older than 4.1.15.  (Bug #27221)

   * `cmd.Parameters.RemoveAt("Id")' will cause an error if the last
     item is requested.  (Bug #27187)

   * `MySqlParameterCollection' and parameters added with `Insert'
     method can not be retrieved later using `ParameterName'.  (Bug
     #27135)

   * Exception thrown when using large values in `UInt64' parameters.
     (Bug #27093)

   * MySQL Visual Studio Plugin 1.1.2 does not work with MySQL
     Connector/Net 5.0.5.  (Bug #26960)


File: manual.info,  Node: connector-net-news-5-0-5,  Next: connector-net-news-5-0-4,  Prev: connector-net-news-5-0-6,  Up: connector-net-news-5-0-x

D.4.9.6 Changes in MySQL Connector/Net 5.0.5 (07 March 2007)
............................................................

*Functionality Added or Changed*

   * Reverted behavior that required parameter names to start with the
     parameter marker. We apologize for this back and forth but we
     mistakenly changed the behavior to not match what `SqlClient'
     supports. We now support using either syntax for adding parameters
     however we also respond exactly like `SqlClient' in that if you
     ask for the index of a parameter using a syntax different from
     when you added the parameter, the result will be -1.

   * Assembly now properly appears in the Visual Studio 2005 Add/Remove
     Reference dialog.

   * Fixed problem that prevented use of `SchemaOnly' or `SingleRow'
     command behaviors with stored procedures or prepared statements.

   * Added `MySqlParameterCollection.AddWithValue' and marked the
     `Add(name, value)' method as obsolete.

   * Return parameters created with DeriveParameters now have the name
     `RETURN_VALUE'.

   * Fixed problem with parameter name hashing where the hashes were
     not getting updated when parameters were removed from the
     collection.

   * Fixed problem with calling stored functions when a return
     parameter was not given.

   * Added `Use Procedure Bodies' connection string option to enable
     calling procedures without using procedure metadata.

*Bugs Fixed*

   * `MySqlConnection.GetSchema' fails with `NullReferenceException'
     for Foreign Keys.  (Bug #26660)

   * MySQL Connector/Net would fail to install under Windows Vista.
     (Bug #26430)

   * Opening a connection would be slow due to host name lookup.  (Bug
     #26152)

   * Incorrect values/formats would be applied when the `OldSyntax'
     connection string option was used.  (Bug #25950)

   * Registry would be incorrectly populated with installation
     locations.  (Bug #25928)

   * Times with negative values would be returned incorrectly.  (Bug
     #25912)

   * Returned data types of a `DataTypes' collection do not contain the
     right correct CLR data type.  (Bug #25907)

   * `GetSchema' and `DataTypes' would throw an exception due to an
     incorrect table name.  (Bug #25906)

   * `MySqlConnection' throws an exception when connecting to MySQL
     v4.1.7.  (Bug #25726)

   * *Note `SELECT': select. did not work correctly when using a
     `WHERE' clause containing a UTF-8 string.  (Bug #25651)

   * When closing and then re-opening a connection to a database, the
     character set specification is lost.  (Bug #25614)

   * Filling a table schema through a stored procedure triggers a
     runtime error.  (Bug #25609)

   * *Note `BINARY': binary-varbinary. and *Note `VARBINARY':
     binary-varbinary. columns would be returned as a string, not
     binary, data type.  (Bug #25605)

   * A critical `ConnectionPool' error would result in repeated
     `System.NullReferenceException'.  (Bug #25603)

   * The `UpdateRowSource.FirstReturnedRecord' method does not work.
     (Bug #25569)

   * When connecting to a MySQL Server earlier than version 4.1, the
     connection would hang when reading data.  (Bug #25458)

   * Using `ExecuteScalar()' with more than one query, where one query
     fails, will hang the connection.  (Bug #25443)

   * When a `MySqlConversionException' is raised on a remote object,
     the client application would receive a `SerializationException'
     instead.  (Bug #24957)

   * When connecting to a server, the return code from the connection
     could be zero, even though the host name was incorrect.  (Bug
     #24802)

   * High CPU utilization would be experienced when there is no idle
     connection waiting when using pooled connections through
     `MySqlPool.GetConnection'.  (Bug #24373)

   * MySQL Connector/Net would not compile properly when used with Mono
     1.2.  (Bug #24263)

   * Applications would crash when calling with `CommandType' set to
     `StoredProcedure'.


File: manual.info,  Node: connector-net-news-5-0-4,  Next: connector-net-news-5-0-3,  Prev: connector-net-news-5-0-5,  Up: connector-net-news-5-0-x

D.4.9.7 Changes in MySQL Connector/Net 5.0.4 (Not released)
...........................................................

This is a new Beta development release, fixing recently discovered bugs.

This section has no changelog entries.


File: manual.info,  Node: connector-net-news-5-0-3,  Next: connector-net-news-5-0-2,  Prev: connector-net-news-5-0-4,  Up: connector-net-news-5-0-x

D.4.9.8 Changes in MySQL Connector/Net 5.0.3 (05 January 2007)
..............................................................

*Functionality Added or Changed*

   * Usage Advisor has been implemented. The Usage Advisor checks your
     queries and will report if you are using the connection
     inefficiently.

   * PerfMon hooks have been added to monitor the stored procedure
     cache hits and misses.

   * The `MySqlCommand' object now supports asynchronous query methods.
     This is implemented useg the `BeginExecuteNonQuery' and
     `EndExecuteNonQuery' methods.

   * Metadata from storaed procedures and stored function execution are
     cached.

   * The `CommandBuilder.DeriveParameters' function has been updated to
     the procedure cache.

   * The `ViewColumns' `GetSchema' collection has been updated.

   * Improved speed and performance by re-architecting certain sections
     of the code.

   * Support for the embedded server and client library have been
     removed from this release. Support will be added back to a later
     release.

   * The ShapZipLib library has been replaced with the deflate support
     provided within .NET 2.0.

   * SSL support has been updated.

*Bugs Fixed*

   * Additional text added to error message (Bug #25178)

   * An exception would be raised, or the process would hang, if
     `SELECT' privileges on a database were not granted and a stored
     procedure was used.  (Bug #25033)

   * When adding parameter objects to a command object, if the
     parameter direction is set to `ReturnValue' before the parameter
     is added to the command object then when the command is executed
     it throws an error.  (Bug #25013)

   * Using `Driver.IsTooOld()' would return the wrong value.  (Bug
     #24661)

   * When using a `DbNull.Value' as the value for a parameter value,
     and then later setting a specific value type, the command would
     fail with an exception because the wrong type was implied from the
     `DbNull.Value'.  (Bug #24565)

   * Stored procedure executions are not thread safe.  (Bug #23905)

   * Deleting a connection to a disconnected server when using the
     Visual Studio Plugin would cause an assertion failure.  (Bug
     #23687)

   * Nested transactions (which are unsupported)do not raise an error
     or warning.  (Bug #22400)


File: manual.info,  Node: connector-net-news-5-0-2,  Next: connector-net-news-5-0-1,  Prev: connector-net-news-5-0-3,  Up: connector-net-news-5-0-x

D.4.9.9 Changes in MySQL Connector/Net 5.0.2 (06 November 2006)
...............................................................

*Functionality Added or Changed*

   * An `Ignore Prepare' option has been added to the connection string
     options. If enabled, prepared statements will be disabled
     application-wide. The default for this option is true.

   * Implemented a stored procedure cache. By default, the connector
     caches the metadata for the last 25 procedures that are seen.  You
     can change the numbver of procedures that are cacheds by using the
     `procedure cache' connection string.

   * *Important change:* Due to a number of issues with the use of
     server-side prepared statements, MySQL Connector/Net 5.0.2 has
     disabled their use by default. The disabling of server-side
     prepared statements does not affect the operation of the connector
     in any way.

     To enable server-side prepared statements you must add the
     following configuration property to your connector string
     properties:

          ignore prepare=false

     The default value of this property is true.

*Bugs Fixed*

   * One system where IPv6 was enabled, MySQL Connector/Net would
     incorrectly resolve host names.  (Bug #23758)

   * Column names with accented characters were not parsed properly
     causing malformed column names in result sets.  (Bug #23657)

   * An exception would be thrown when calling `GetSchemaTable' and
     `fields' was null.  (Bug #23538)

   * A `System.FormatException' exception would be raised when invoking
     a stored procedure with an *Note `ENUM': enum. input parameter.
     (Bug #23268)

   * During installation, an antivirus error message would be raised
     (indicating a malicious script problem).  (Bug #23245)

   * Creating a connection through the Server Explorer when using the
     Visual Studio Plugin would fail. The installer for the Visual
     Studio Plugin has been updated to ensure that MySQL Connector/Net
     5.0.2 must be installed.  (Bug #23071)

   * Using Windows Vista (RC2) as a nonprivileged user would raise a
     `Registry key 'Global' access denied'.  (Bug #22882)

   * Within Mono, using the `PreparedStatement' interface could result
     in an error due to a `BitArray' copying error.  (Bug #18186)

   * MySQL Connector/Net did not work as a data source for the
     `SqlDataSource' object used by ASP.NET 2.0.  (Bug #16126)


File: manual.info,  Node: connector-net-news-5-0-1,  Next: connector-net-news-5-0-0,  Prev: connector-net-news-5-0-2,  Up: connector-net-news-5-0-x

D.4.9.10 Changes in MySQL Connector/Net 5.0.1 (01 October 2006)
...............................................................

*Bugs Fixed*

   * MySQL Connector/Net on a Turkish operating system, may fail to
     execute certain SQL statements correctly.  (Bug #22452)

   * Starting a transaction on a connection created by
     `MySql.Data.MySqlClient.MySqlClientFactory', using
     `BeginTransaction' without specifying an isolation level, causes
     the SQL statement to fail with a syntax error.  (Bug #22042)

   * The `MySqlexception' class is now derived from the `DbException'
     class.  (Bug #21874)

   * The `#' would not be accepted within column/table names, even
     though it was valid.  (Bug #21521)

   * You can now install the MySQL Connector/Net MSI package from the
     command line using the `/passive', `/quiet', `/q' options.  (Bug
     #19994)

   * Submitting an empty string to a command object through `prepare'
     raises an `System.IndexOutOfRangeException', rather than a MySQL
     Connector/Net exception.  (Bug #18391)

   * Incorrect field/data lengths could be returned for *Note
     `VARCHAR': char. UTF8 columns.  (Bug #14592)

   * Using `ExecuteScalar' with a datetime field, where the value of
     the field is "0000-00-00 00:00:00", a `MySqlConversionException'
     exception would be raised.  (Bug #11991)

   * An `MySql.Data.Types.MySqlConversionException' would be raised
     when trying to update a row that contained a date field, where the
     date field contained a zero value (0000-00-00 00:00:00).  (Bug
     #9619)

   * Executing multiple queries as part of a transaction returns `There
     is already an openDataReader associated with this Connection which
     must be closed first'.  (Bug #7248)


File: manual.info,  Node: connector-net-news-5-0-0,  Prev: connector-net-news-5-0-1,  Up: connector-net-news-5-0-x

D.4.9.11 Changes in MySQL Connector/Net 5.0.0 (08 August 2006)
..............................................................

*Functionality Added or Changed*

   * Replaced use of ICSharpCode with .NET 2.0 internal deflate support.

   * Refactored test suite to test all protocols in a single pass.

   * Added usage advisor warnings for requesting column values by the
     wrong type.

   * Reimplemented PacketReader/PacketWriter support into MySqlStream
     class.

   * Reworked connection string classes to be simpler and faster.

   * Added procedure metadata caching.

   * Added internal implemention of SHA1 so we don't have to distribute
     the OpenNetCF on mobile devices.

   * Implemented MySqlClientFactory class.

   * Added perfmon hooks for stored procedure cache hits and misses.

   * Implemented classes and interfaces for ADO.Net 2.0 support.

   * Added Async query methods.

   * Implemented Usage Advisor.

   * Completely refactored how column values are handled to avoid
     boxing in some cases.

   * Implemented MySqlConnectionBuilder class.

*Bugs Fixed*

   * CommandText: Question mark in comment line is being parsed as a
     parameter.  (Bug #6214)


File: manual.info,  Node: connector-net-news-1-0-x,  Next: connector-net-news-0-9-0,  Prev: connector-net-news-5-0-x,  Up: connector-net-news

D.4.10 Changes in MySQL Connector/Net Version 1.0.x
---------------------------------------------------

* Menu:

* connector-net-news-1-0-11::    Changes in MySQL Connector/Net 1.0.11 (Not released)
* connector-net-news-1-0-10::    Changes in MySQL Connector/Net 1.0.10 (24 August 2007)
* connector-net-news-1-0-9::     Changes in MySQL Connector/Net 1.0.9 (02 February 2007)
* connector-net-news-1-0-8::     Changes in MySQL Connector/Net 1.0.8 (20 October 2006)
* connector-net-news-1-0-7::     Changes in MySQL Connector/Net 1.0.7 (21 November 2005)
* connector-net-news-1-0-6::     Changes in MySQL Connector/Net 1.0.6 (03 October 2005)
* connector-net-news-1-0-5::     Changes in MySQL Connector/Net 1.0.5 (29 August 2005)
* connector-net-news-1-0-4::     Changes in MySQL Connector/Net 1.0.4 (20 January 2005)
* connector-net-news-1-0-3::     Changes in MySQL Connector/Net 1.0.3 (12 October 2004 gamma)
* connector-net-news-1-0-2::     Changes in MySQL Connector/Net 1.0.2 (15 November 2004 gamma)
* connector-net-news-1-0-1::     Changes in MySQL Connector/Net 1.0.1 (27 October 2004 beta)
* connector-net-news-1-0-0::     Changes in MySQL Connector/Net 1.0.0 (01 September 2004)


File: manual.info,  Node: connector-net-news-1-0-11,  Next: connector-net-news-1-0-10,  Prev: connector-net-news-1-0-x,  Up: connector-net-news-1-0-x

D.4.10.1 Changes in MySQL Connector/Net 1.0.11 (Not released)
.............................................................

*Bugs Fixed*

   * Attempting to utilize MySQL Connector .Net version 1.0.10 throws a
     fatal exception under Mono when pooling is enabled.  (Bug #33682)

   * Setting the size of a string parameter after the value could cause
     an exception.  (Bug #32094)

   * Creation of parameter objects with noninput direction using a
     constructor would fail. This was cause by some old legacy code
     preventing their use.  (Bug #32093)

   * Memory usage could increase and decrease significantly when
     updating or inserting a large number of rows.  (Bug #31090)

   * Commands executed from within the state change handeler would fail
     with a `NULL' exception.  (Bug #30964)

   * Extracting data through XML functions within a query returns the
     data as `System.Byte[]'. This was due to MySQL Connector/Net
     incorrectly identifying *Note `BLOB': blob.  fields as binary,
     rather than text.  (Bug #30233)

   * Using compression in the MySQL connection with MySQL Connector/Net
     would be slower than using native (uncompressed) communication.
     (Bug #27865)

   * Changing the connection string of a connection to one that changes
     the parameter marker after the connection had been assigned to a
     command but before the connection is opened could cause parameters
     to not be found.  (Bug #13991)


File: manual.info,  Node: connector-net-news-1-0-10,  Next: connector-net-news-1-0-9,  Prev: connector-net-news-1-0-11,  Up: connector-net-news-1-0-x

D.4.10.2 Changes in MySQL Connector/Net 1.0.10 (24 August 2007)
...............................................................

*Bugs Fixed*

   * An incorrect `ConstraintException' could be raised on an *Note
     `INSERT': insert. when adding rows to a table with a
     multiple-column unique key index.  (Bug #30204)

   * The availability of a MySQL server would not be reset when using
     pooled connections (`pooling=true'). This would lead to the server
     being reported as unavailable, even if the server become available
     while the application was still running.  (Bug #29409)

   * Publisher listed in "Add/Remove Programs" is not consistent with
     other MySQL products.  (Bug #27253)

   * `MySqlParameterCollection' and parameters added with `Insert'
     method can not be retrieved later using `ParameterName'.  (Bug
     #27135)

   * *Note `BINARY': binary-varbinary. and *Note `VARBINARY':
     binary-varbinary. columns would be returned as a string, not
     binary, data type.  (Bug #25605)

   * A critical `ConnectionPool' error would result in repeated
     `System.NullReferenceException'.  (Bug #25603)

   * When a `MySqlConversionException' is raised on a remote object,
     the client application would receive a `SerializationException'
     instead.  (Bug #24957)

   * High CPU utilization would be experienced when there is no idle
     connection waiting when using pooled connections through
     `MySqlPool.GetConnection'.  (Bug #24373)


File: manual.info,  Node: connector-net-news-1-0-9,  Next: connector-net-news-1-0-8,  Prev: connector-net-news-1-0-10,  Up: connector-net-news-1-0-x

D.4.10.3 Changes in MySQL Connector/Net 1.0.9 (02 February 2007)
................................................................

*Functionality Added or Changed*

   * The ICSharpCode ZipLib is no longer used by the Connector, and is
     no longer distributed with it.

   * *Important change:* Binaries for .NET 1.0 are no longer supplied
     with this release. If you need support for .NET 1.0, you must
     build from source.

   * Improved `CommandBuilder.DeriveParameters' to first try and use
     the procedure cache before querying for the stored procedure
     metadata. Return parameters created with `DeriveParameters' now
     have the name `RETURN_VALUE'.

   * An `Ignore Prepare' option has been added to the connection string
     options. If enabled, prepared statements will be disabled
     application-wide. The default for this option is true.

   * Implemented a stored procedure cache. By default, the connector
     caches the metadata for the last 25 procedures that are seen.  You
     can change the numbver of procedures that are cacheds by using the
     `procedure cache' connection string.

   * *Important change:* Due to a number of issues with the use of
     server-side prepared statements, MySQL Connector/Net 5.0.2 has
     disabled their use by default. The disabling of server-side
     prepared statements does not affect the operation of the connector
     in any way.

     To enable server-side prepared statements you must add the
     following configuration property to your connector string
     properties:

          ignore prepare=false

     The default value of this property is true.

*Bugs Fixed*

   * Times with negative values would be returned incorrectly.  (Bug
     #25912)

   * `MySqlConnection' throws a `NullReferenceException' and
     `ArgumentNullException' when connecting to MySQL v4.1.7.  (Bug
     #25726)

   * *Note `SELECT': select. did not work correctly when using a
     `WHERE' clause containing a UTF-8 string.  (Bug #25651)

   * When closing and then re-opening a connection to a database, the
     character set specification is lost.  (Bug #25614)

   * Trying to fill a table schema through a stored procedure triggers
     a runtime error.  (Bug #25609)

   * Using `ExecuteScalar()' with more than one query, where one query
     fails, will hang the connection.  (Bug #25443)

   * Additional text added to error message.  (Bug #25178)

   * When adding parameter objects to a command object, if the
     parameter direction is set to `ReturnValue' before the parameter
     is added to the command object then when the command is executed
     it throws an error.  (Bug #25013)

   * When connecting to a server, the return code from the connection
     could be zero, even though the host name was incorrect.  (Bug
     #24802)

   * Using `Driver.IsTooOld()' would return the wrong value.  (Bug
     #24661)

   * When using a `DbNull.Value' as the value for a parameter value,
     and then later setting a specific value type, the command would
     fail with an exception because the wrong type was implied from the
     `DbNull.Value'.  (Bug #24565)

   * Stored procedure executions are not thread safe.  (Bug #23905)

   * The `CommandBuilder' would mistakenly add insert parameters for a
     table column with auto incrementation enabled.  (Bug #23862)

   * One system where IPv6 was enabled, MySQL Connector/Net would
     incorrectly resolve host names.  (Bug #23758)

   * An `System.OverflowException' would be raised when accessing a
     varchar field over 255 bytes.  (Bug #23749)

   * Nested transactions do not raise an error or warning.  (Bug #22400)

   * Within Mono, using the `PreparedStatement' interface could result
     in an error due to a `BitArray' copying error.  (Bug #18186)


File: manual.info,  Node: connector-net-news-1-0-8,  Next: connector-net-news-1-0-7,  Prev: connector-net-news-1-0-9,  Up: connector-net-news-1-0-x

D.4.10.4 Changes in MySQL Connector/Net 1.0.8 (20 October 2006)
...............................................................

*Functionality Added or Changed*

   * Stored procedures are now cached.

   * The method for retrieving stored procedure metadata has been
     changed so that users without `SELECT' privileges on the
     `mysql.proc' table can use a stored procedure.

*Bugs Fixed*

   * MySQL Connector/Net on a Turkish operating system, may fail to
     execute certain SQL statements correctly.  (Bug #22452)

   * The `#' would not be accepted within column/table names, even
     though it was valid.  (Bug #21521)

   * Calling Close on a connection after calling a stored procedure
     would trigger a `NullReferenceException'.  (Bug #20581)

   * You can now install the MySQL Connector/Net MSI package from the
     command line using the `/passive', `/quiet', `/q' options.  (Bug
     #19994)

   * The DiscoverParameters function would fail when a stored procedure
     used a *Note `NUMERIC': numeric-types.  parameter type.  (Bug
     #19515)

   * When running a query that included a date comparison, a DateReader
     error would be raised.  (Bug #19481)

   * `IDataRecord.GetString' would raise `NullPointerException' for
     null values in returned rows. Method now throws
     `SqlNullValueException'.  (Bug #19294)

   * Parameter substitution in queries where the order of parameters
     and table fields did not match would substitute incorrect values.
     (Bug #19261)

   * Submitting an empty string to a command object through `prepare'
     raises an `System.IndexOutOfRangeException', rather than a MySQL
     Connector/Net exception.  (Bug #18391)

   * An exception would be raised when using an output parameter to a
     `System.String' value.  (Bug #17814)

   * CHAR type added to MySqlDbType.  (Bug #17749)

   * A *Note `SELECT': select. query on a table with a date with a
     value of `'0000-00-00'' would hang the application.  (Bug #17736)

   * The CommandBuilder ignored Unsigned flag at Parameter creation.
     (Bug #17375)

   * When working with multiple threads, character set initialization
     would generate errors.  (Bug #17106)

   * When using an unsigned 64-bit integer in a stored procedure, the
     unsigned bit would be lost stored.  (Bug #16934)

   * `DataReader' would show the value of the previous row (or last row
     with nonnull data) if the current row contained a `datetime' field
     with a null value.  (Bug #16884)

   * Unsigned data types were not properly supported.  (Bug #16788)

   * The connection string parser did not permit single or double
     quotation marks in the password.  (Bug #16659)

   * The `MySqlDateTime' class did not contain constructors.  (Bug
     #15112)

   * Called `MySqlCommandBuilder.DeriveParameters' for a stored
     procedure that has no paramers would cause an application crash.
     (Bug #15077)

   * Incorrect field/data lengths could be returned for *Note
     `VARCHAR': char. UTF8 columns.  (Bug #14592)

   * Using `ExecuteScalar' with a datetime field, where the value of
     the field is "0000-00-00 00:00:00", a `MySqlConversionException'
     exception would be raised.  (Bug #11991)

   * An `MySql.Data.Types.MySqlConversionException' would be raised
     when trying to update a row that contained a date field, where the
     date field contained a zero value (0000-00-00 00:00:00).  (Bug
     #9619)

   * When using `MySqlDataAdapter', connections to a MySQL server may
     remain open and active, even though the use of the connection has
     been completed and the data received.  (Bug #8131)

   * Executing multiple queries as part of a transaction returns `There
     is already an openDataReader associated with this Connection which
     must be closed first'.  (Bug #7248)


File: manual.info,  Node: connector-net-news-1-0-7,  Next: connector-net-news-1-0-6,  Prev: connector-net-news-1-0-8,  Up: connector-net-news-1-0-x

D.4.10.5 Changes in MySQL Connector/Net 1.0.7 (21 November 2005)
................................................................

*Bugs Fixed*

   * Unsigned `tinyint' (NET byte) would lead to and incorrectly
     determined parameter type from the parameter value.  (Bug #18570)

   * A `#42000Query was empty' exception occurred when executing a
     query built with `MySqlCommandBuilder', if the query string ended
     with a semicolon.  (Bug #14631)

   * The parameter collection object's `Add()' method added parameters
     to the list without first checking to see whether they already
     existed. Now it updates the value of the existing parameter object
     if it exists.  (Bug #13927)

   * Added support for the `cp932' character set.  (Bug #13806)

   * Calling a stored procedure where a parameter contained special
     characters (such as `'@'') would produce an exception. Note that
     `ANSI_QUOTES' had to be enabled to make this possible.  (Bug
     #13753)

   * The `Ping()' method did not update the `State' property of the
     `Connection' object.  (Bug #13658)

   * Implemented the `MySqlCommandBuilder.DeriveParameters' method that
     is used to discover the parameters for a stored procedure.  (Bug
     #13632)

   * A statement that contained multiple references to the same
     parameter could not be prepared.  (Bug #13541)


File: manual.info,  Node: connector-net-news-1-0-6,  Next: connector-net-news-1-0-5,  Prev: connector-net-news-1-0-7,  Up: connector-net-news-1-0-x

D.4.10.6 Changes in MySQL Connector/Net 1.0.6 (03 October 2005)
...............................................................

*Bugs Fixed*

   * MySQL Connector/Net 1.0.5 could not connect on Mono.  (Bug #13345)

   * Serializing a parameter failed if the first value passed in was
     `NULL'.  (Bug #13276)

   * Field names that contained the following characters caused errors:
     `()%<>/' (Bug #13036)

   * The `nant' build sequence had problems.  (Bug #12978)

   * The MySQL Connector/Net 1.0.5 installer would not install
     alongside MySQL Connector/Net 1.0.4.  (Bug #12835)


File: manual.info,  Node: connector-net-news-1-0-5,  Next: connector-net-news-1-0-4,  Prev: connector-net-news-1-0-6,  Up: connector-net-news-1-0-x

D.4.10.7 Changes in MySQL Connector/Net 1.0.5 (29 August 2005)
..............................................................

*Bugs Fixed*

   * MySQL Connector/Net could not connect to MySQL 4.1.14.  (Bug
     #12771)

   * With multiple hosts in the connection string, MySQL Connector/Net
     would not connect to the last host in the list.  (Bug #12628)

   * The `ConnectionString' property could not be set when a
     `MySqlConnection' object was added with the designer.  (Bug
     #12551, Bug #8724)

   * The `cp1250' character set was not supported.  (Bug #11621)

   * A call to a stored procedure caused an exception if the stored
     procedure had no parameters.  (Bug #11542)

   * Certain malformed queries would trigger a `Connection must be
     valid and open' error message.  (Bug #11490)

   * Trying to use a stored procedure when `Connection.Database' was
     not populated generated an exception.  (Bug #11450)

   * MySQL Connector/Net interpreted the new decimal data type as a
     byte array.  (Bug #11294)

   * Added support to call a stored function from MySQL Connector/Net.
     (Bug #10644)

   * Connection could fail when .NET thread pool had no available
     worker threads.  (Bug #10637)

   * Calling `MySqlConnection.clone' when a connection string had not
     yet been set on the original connection would generate an error.
     (Bug #10281)

   * Decimal parameters caused syntax errors.  (Bug #10152, Bug #11550,
     Bug #10486)

   * Parameters were not recognized when they were separated by
     linefeeds.  (Bug #9722)

   * The `MySqlCommandBuilder' class could not handle queries that
     referenced tables in a database other than the default database.
     (Bug #8382)

   * Trying to read a *Note `TIMESTAMP': datetime. column generated an
     exception.  (Bug #7951)

   * MySQL Connector/Net could not work properly with certain regional
     settings.  (WL#8228)


File: manual.info,  Node: connector-net-news-1-0-4,  Next: connector-net-news-1-0-3,  Prev: connector-net-news-1-0-5,  Up: connector-net-news-1-0-x

D.4.10.8 Changes in MySQL Connector/Net 1.0.4 (20 January 2005)
...............................................................

*Bugs Fixed*

   * `MySqlReader.GetInt32' throws exception if column is unsigned.
     (Bug #7755)

   * Quote character \222 not quoted in `EscapeString'.  (Bug #7724)

   * GetBytes is working no more.  (Bug #7704)

   * `MySqlDataReader.GetString(index)' returns non-Null value when
     field is `Null'.  (Bug #7612)

   * Clone method bug in `MySqlCommand'.  (Bug #7478)

   * Problem with Multiple resultsets.  (Bug #7436)

   * `MySqlAdapter.Fill' method throws error message `Non-negative
     number required'.  (Bug #7345)

   * `MySqlCommand.Connection' returns an IDbConnection.  (Bug #7258)

   * Calling prepare causing exception.  (Bug #7243)

   * Fixed problem with shared memory connections.

   * Added or filled out several more topics in the API reference
     documentation.

   * Fixed another small problem with prepared statements.

   * Fixed problem that causes named pipes to not work with some blob
     functionality.


File: manual.info,  Node: connector-net-news-1-0-3,  Next: connector-net-news-1-0-2,  Prev: connector-net-news-1-0-4,  Up: connector-net-news-1-0-x

D.4.10.9 Changes in MySQL Connector/Net 1.0.3 (12 October 2004 gamma)
.....................................................................

*Bugs Fixed*

   * Invalid query string when using inout parameters (Bug #7133)

   * Inserting `DateTime' causes `System.InvalidCastException' to be
     thrown.  (Bug #7132)

   * `MySqlDateTime' in Datatables sorting by Text, not Date.  (Bug
     #7032)

   * Exception stack trace lost when re-throwing exceptions.  (Bug
     #6983)

   * Errors in parsing stored procedure parameters.  (Bug #6902)

   * InvalidCast when using `DATE_ADD'-function.  (Bug #6879)

   * Int64 Support in `MySqlCommand' Parameters.  (Bug #6863)

   * Test suite fails with MySQL 4.0 because of case sensitivity of
     table names.  (Bug #6831)

   * `MySqlDataReader.GetChar(int i)' throws `IndexOutOfRange'
     exception.  (Bug #6770)

   * Integer "out" parameter from stored procedure returned as string.
     (Bug #6668)

   * An Open Connection has been Closed by the Host System.  (Bug #6634)

   * Fixed Invalid character set index: 200.  (Bug #6547)

   * Connections now do not have to give a database on the connection
     string.

   * Installer now includes options to install into GAC and create
     `Start Menu' items.

   * Fixed major problem with detecting null values when using prepared
     statements.

   * Fixed problem where multiple resultsets having different numbers
     of columns would cause a problem.

   * Added `ServerThread' property to `MySqlConnection' to expose
     server thread id.

   * Added Ping method to `MySqlConnection'.

   * Changed the name of the test suite to `MySql.Data.Tests.dll'.

   * Now *Note `SHOW COLLATION': show-collation. is used upon
     connection to retrieve the full list of charset ids.

   * Made MySQL the default named pipe name.


File: manual.info,  Node: connector-net-news-1-0-2,  Next: connector-net-news-1-0-1,  Prev: connector-net-news-1-0-3,  Up: connector-net-news-1-0-x

D.4.10.10 Changes in MySQL Connector/Net 1.0.2 (15 November 2004 gamma)
.......................................................................

*Bugs Fixed*

   * Fixed Objects not being disposed (Bug #6649)

   * Fixed Charset-map for UCS-2 (Bug #6541)

   * Fixed Zero date "0000-00-00" is returned wrong when filling Dataset
     (Bug #6429)

   * Fixed double type handling in MySqlParameter(string parameterName,
     object value).  (Bug #6428)

   * Fixed Installation directory ignored using custom installation
     (Bug #6329)

   * Fixed #HY000 Illegal mix of collations
     (latin1_swedish_ci,IMPLICIT) and (utf8_general_ (Bug #6322)

   * Added the TableEditor CS and VB sample

   * Added charset connection string option

   * Fixed problem with MySqlBinary where string values could not be
     used to update extended text columns

   * Provider is now using character set specified by server as default

   * Updated the installer to include the new samples

   * Fixed problem where setting command text leaves the command in a
     prepared state

   * Fixed Long inserts take very long time (Bu #5453)

   * Fixed problem where calling stored procedures might cause an
     "Illegal mix of collations" problem.


File: manual.info,  Node: connector-net-news-1-0-1,  Next: connector-net-news-1-0-0,  Prev: connector-net-news-1-0-2,  Up: connector-net-news-1-0-x

D.4.10.11 Changes in MySQL Connector/Net 1.0.1 (27 October 2004 beta)
.....................................................................

*Bugs Fixed*

   * Fixed IndexOutOfBounds when reading `BLOB' with `DataReader' with
     `GetString(index)'.  (Bug #6230)

   * Fixed GetBoolean returns wrong values (Bug #6227)

   * Fixed Method TokenizeSql() uses only a limited set of valid
     characters for parameters (Bug #6217)

   * Fixed NET Connector source missing resx files (Bug #6216)

   * Fixed System.OverflowException when using `YEAR' data type.  (Bug
     #6036)

   * Fixed MySqlDateTime sets IsZero property on all subseq.records
     after first zero found (Bug #6006)

   * Fixed serializing of floating point parameters (double, numeric,
     single, decimal) (Bug #5900)

   * Fixed missing Reference in DbType setter (Bug #5897)

   * Fixed Parsing the ';' char (Bug #5876)

   * Fixed DBNull Values causing problems with retrieving/updating
     queries.  (Bug #5798)

   * IsNullable error (Bug #5796)

   * Fixed problem where MySqlParameterCollection.Add() would throw
     unclear exception when given a null value (Bug #5621)

   * Fixed constructor initialize problems in MySqlCommand() (Bug #5613)

   * Possible bug in MySqlParameter(string, object) constructor (Bug
     #5602)

   * Fixed Yet Another "object reference not set to an instance of an
     object" (Bug #5496)

   * Cannot run a stored procedure populating mysqlcommand.parameters
     (Bug #5474)

   * Setting `DbType' threw a `NullReferenceException'.  (Bug #5469)

   * Calling `GetChars' on a `LONGTEXT' column threw an exception.
     (Bug #5458)

   * `MySqlCommand' saw instances of `"?"' as parameters in string
     literals.  (Bug #5392)

   * `DataReader' reported all rows as `NULL' if one row was `NULL'.
     (Bug #5388)

   * Fixed Can't display Chinese correctly (Bug #5288)

   * Fixed MySqlDataReader and 'show tables from ...' behavior (Bug
     #5256)

   * Fixed problem in PacketReader where it could try to allocate the
     wrong buffer size in EnsureCapacity

   * Fixed problem where using old syntax while using the interfaces
     caused problems

   * Added test case for resetting the command text on a prepared
     command

   * Fixed problem where connection lifetime on the connect string was
     not being respected

   * Field buffers being reused to decrease memory allocations and
     increase speed

   * Added Aggregate function test (wasn't really a bug)

   * Using PacketWriter instead of Packet for writing to streams

   * Implemented SequentialAccess

   * Fixed problem with ConnectionInternal where a key might be added
     more than once

   * Fixed Russian character support as well

   * Fixed problem where connector was not issuing a CMD_QUIT before
     closing the socket

   * Fixed problem where Min Pool Size was not being respected

   * Refactored compression code into CompressedStream to clean up
     NativeDriver

   * CP1252 is now used for Latin1 only when the server is 4.1.2 and
     later

   * Virtualized driver subsystem so future releases could easily
     support client or embedded server support


File: manual.info,  Node: connector-net-news-1-0-0,  Prev: connector-net-news-1-0-1,  Up: connector-net-news-1-0-x

D.4.10.12 Changes in MySQL Connector/Net 1.0.0 (01 September 2004)
..................................................................

*Bugs Fixed*

   * Thai encoding not correctly supported.  (Bug #3889)

   * Bumped version number to 1.0.0 for beta 1 release.

   * Removed all of the XML comment warnings.

   * Added `COPYING.rtf' file for use in installer.

   * Updated many of the test cases.

   * Fixed problem with using compression.

   * Removed some last references to ByteFX.


File: manual.info,  Node: connector-net-news-0-9-0,  Next: connector-net-news-0-76,  Prev: connector-net-news-1-0-x,  Up: connector-net-news

D.4.11 Changes in MySQL Connector/Net Version 0.9.0 (30 August 2004)
--------------------------------------------------------------------

   * Added test fixture for prepared statements.

   * All type classes now implement a `SerializeBinary' method for
     sending their data to a `PacketWriter'.

   * Added `PacketWriter' class that will enable future low-memory
     large object handling.

   * Fixed many small bugs in running prepared statements and stored
     procedures.

   * Changed command so that an exception will not be thrown in
     executing a stored procedure with parameters in old syntax mode.

   * `SingleRow' behavior now working right even with limit.

   * `GetBytes' now only works on binary columns.

   * Logger now truncates long SQL commands so blob columns do not blow
     out our log.

   * Host and database now have a default value of "" unless otherwise
     set.

   * Connection Timeout seems to be ignored. (Bug #5214)

   * Added test case for bug# 5051: GetSchema not working correctly.

   * Fixed problem where `GetSchema' would return false for `IsUnique'
     when the column is key.

   * `MySqlDataReader GetXXX' methods now using the field level
     `MySqlValue' object and not performing conversions.

   * `DataReader' returning `NULL' for time column. (Bug #5097)

   * Added test case for *Note `LOAD DATA LOCAL INFILE': load-data.

   * Added replacetext custom nant task.

   * Added `CommandBuilderTest' fixture.

   * Added Last One Wins feature to `CommandBuilder'.

   * Fixed persist security info case problem.

   * Fixed `GetBool' so that 1, true, "true", and "yes" all count as
     true.

   * Make parameter mark configurable.

   * Added the "old syntax" connection string parameter to enable use
     of @ parameter marker.

   * `MySqlCommandBuilder'. (Bug #4658)

   * `ByteFX.MySqlClient' caches passwords if `Persist Security Info'
     is false. (Bug #4864)

   * Updated license banner in all source files to include FLOSS
     exception.

   * Added new .Types namespace and implementations for most current
     MySql types.

   * Added `MySqlField41' as a subclass of `MySqlField'.

   * Changed many classes to now use the new .Types types.

   * Changed type `enum int' to `Int32', `short' to `Int16', and
     `bigint' to `Int64'.

   * Added dummy types `UInt16', `UInt32', and `UInt64' to allow an
     unsigned parameter to be made.

   * Connections are now reset when they are pulled from the connection
     pool.

   * Refactored auth code in driver so it can be used for both auth and
     reset.

   * Added `UserReset' test in `PoolingTests.cs'.

   * Connections are now reset using `COM_CHANGE_USER' when pulled from
     the pool.

   * Implemented `SingleResultSet' behavior.

   * Implemented support of unicode.

   * Added char set mappings for utf-8 and ucs-2.

   * Time fields overflow using bytefx .net mysql driver (Bug #4520)

   * Modified time test in data type test fixture to check for time
     spans where hours > 24.

   * Wrong string with backslash escaping in
     `ByteFx.Data.MySqlClient.MySqlParameter'.  (Bug #4505)

   * Added code to Parameter test case TestQuoting to test for
     backslashes.

   * `MySqlCommandBuilder' fails with multi-word column names. (Bug
     #4486)

   * Fixed bug in `TokenizeSql' where underscore would terminate
     character capture in parameter name.

   * Added test case for spaces in column names.

   * `MySqlDataReader.GetBytes' do not work correctly. (Bug #4324)

   * Added `GetBytes()' test case to `DataReader' test fixture.

   * Now reading all server variables in `InternalConnection.Configure'
     into `Hashtable'.

   * Now using `string[]' for index map in `CharSetMap'.

   * Added CRInSQL test case for carriage returns in SQL.

   * Setting maxPacketSize to default value in `Driver.ctor'.

   * Setting `MySqlDbType' on a parameter doesn't set generic type.
     (Bug #4442)

   * Removed obsolete data types `Long' and `LongLong'.

   * Overflow exception thrown when using "use pipe" on connection
     string. (Bug #4071)

   * Changed "use pipe" keyword to "pipe name" or just "pipe".

   * Enable reading multiple resultsets from a single query.

   * Added flags attribute to `ServerStatusFlags' enum.

   * Changed name of `ServerStatus' enum to `ServerStatusFlags'.

   * Inserted data row doesn't update properly.

   * Error processing show create table. (Bug #4074)

   * Change `Packet.ReadLenInteger' to `ReadPackedLong' and added
     `packet.ReadPackedInteger' that always reads integers packed with
     2,3,4.

   * Added `syntax.cs' test fixture to test various SQL syntax bugs.

   * Improper handling of time values. Now time value of 00:00:00 is
     not treated as null. (Bug #4149)

   * Moved all test suite files into `TestSuite' folder.

   * Fixed bug where null column would move the result packet pointer
     backward.

   * Added new nant build script.

   * Clear tablename so it will be regen'ed properly during the next
     `GenerateSchema'. (Bug #3917)

   * `GetValues' was always returning zero and was also always trying
     to copy all fields rather than respecting the size of the array
     passed in. (Bug #3915)

   * Implemented shared memory access protocol.

   * Implemented prepared statements for MySQL 4.1.

   * Implemented stored procedures for MySQL 5.0.

   * Renamed `MySqlInternalConnection' to `InternalConnection'.

   * SQL is now parsed as chars, fixes problems with other languages.

   * Added logging and allow batch connection string options.

   * `RowUpdating' event not set when setting the `DataAdapter'
     property. (Bug #3888)

   * Fixed bug in char set mapping.

   * Implemented 4.1 authentication.

   * Improved open/auth code in driver.

   * Improved how connection bits are set during connection.

   * Database name is now passed to server during initial handshake.

   * Changed namespace for client to `MySql.Data.MySqlClient'.

   * Changed assembly name of client to `MySql.Data.dll'.

   * Changed license text in all source files to GPL.

   * Added the `MySqlClient.build' Nant file.

   * Removed the mono batch files.

   * Moved some of the unused files into notused folder so nant build
     file can use wildcards.

   * Implemented shared memory access.

   * Major revamp in code structure.

   * Prepared statements now working for MySql 4.1.1 and later.

   * Finished implementing auth for 4.0, 4.1.0, and 4.1.1.

   * Changed namespace from `MySQL.Data.MySQLClient' back to
     `MySql.Data.MySqlClient'.

   * Fixed bug in `CharSetMapping' where it was trying to use text
     names as ints.

   * Changed namespace to `MySQL.Data.MySQLClient'.

   * Integrated auth changes from UC2004.

   * Fixed bug where calling any of the GetXXX methods on a datareader
     before or after reading data would not throw the appropriate
     exception (thanks Luca Morelli).

   * Added `TimeSpan' code in parameter.cs to properly serialize a
     timespan object to mysql time format (thanks Gianluca Colombo).

   * Added `TimeStamp' to parameter serialization code. Prevented
     `DataAdapter' updates from working right (thanks Michael King).

   * Fixed a misspelling in `MySqlHelper.cs' (thanks Patrick
     Kristiansen).


File: manual.info,  Node: connector-net-news-0-76,  Next: connector-net-news-0-75,  Prev: connector-net-news-0-9-0,  Up: connector-net-news

D.4.12 Changes in MySQL Connector/Net Version 0.76
--------------------------------------------------

   * Driver now using charset number given in handshake to create
     encoding.

   * Changed command editor to point to `MySqlClient.Design'.

   * Fixed bug in `Version.isAtLeast'.

   * Changed `DBConnectionString' to support changes done to
     `MySqlConnectionString'.

   * Removed `SqlCommandEditor' and `DataAdapterPreviewDialog'.

   * Using new long return values in many places.

   * Integrated new `CompressedStream' class.

   * Changed `ConnectionString' and added attributes to permit it to be
     used in `MySqlClient.Design'.

   * Changed `packet.cs' to support newer lengths in `ReadLenInteger'.

   * Changed other classes to use new properties and fields of
     `MySqlConnectionString'.

   * `ConnectionInternal' is now using PING to see whether the server
     is available.

   * Moved toolbox bitmaps into resource folder.

   * Changed `field.cs' to permit values to come directly from row
     buffer.

   * Changed to use the new driver.Send syntax.

   * Using a new packet queueing system.

   * Started work handling the "broken" compression packet handling.

   * Fixed bug in `StreamCreator' where failure to connect to a host
     would continue to loop infinitely (thanks Kevin Casella).

   * Improved connectstring handling.

   * Moved designers into Pro product.

   * Removed some old commented out code from `command.cs'.

   * Fixed a problem with compression.

   * Fixed connection object where an exception throw prior to the
     connection opening would not leave the connection in the
     connecting state (thanks Chris Cline).

   * Added GUID support.

   * Fixed sequence out of order bug (thanks Mark Reay).


File: manual.info,  Node: connector-net-news-0-75,  Next: connector-net-news-0-74,  Prev: connector-net-news-0-76,  Up: connector-net-news

D.4.13 Changes in MySQL Connector/Net Version 0.75
--------------------------------------------------

   * Enum values now supported as parameter values (thanks Philipp
     Sumi).

   * Year data type now supported.

   * Fixed compression.

   * Fixed bug where a parameter with a `TimeSpan' as the value would
     not serialize properly.

   * Fixed bug where default constructor would not set default
     connection string values.

   * Added some XML comments to some members.

   * Work to fix/improve compression handling.

   * Improved `ConnectionString' handling so that it better matches the
     standard set by `SqlClient'.

   * A `MySqlException' is now thrown if a user name is not included in
     the connection string.

   * Localhost is now used as the default if not specified on the
     connection string.

   * An exception is now thrown if an attempt is made to set the
     connection string while the connection is open.

   * Small changes to `ConnectionString' docs.

   * Removed `MultiHostStream' and `MySqlStream'. Replaced it with
     `Common/StreamCreator'.

   * Added support for Use Pipe connection string value.

   * Added Platform class for easier access to platform utility
     functions.

   * Fixed small pooling bug where new connection was not getting
     created after `IsAlive' fails.

   * Added `Platform.cs' and `StreamCreator.cs'.

   * Fixed `Field.cs' to properly handle 4.1 style timestamps.

   * Changed `Common.Version' to `Common.DBVersion' to avoid name
     conflict.

   * Fixed `field.cs' so that text columns return the right field type.

   * Added `MySqlError' class to provide some reference for error codes
     (thanks Geert Veenstra).


File: manual.info,  Node: connector-net-news-0-74,  Next: connector-net-news-0-71,  Prev: connector-net-news-0-75,  Up: connector-net-news

D.4.14 Changes in MySQL Connector/Net Version 0.74
--------------------------------------------------

   * Added Unix socket support (thanks Mohammad DAMT).

   * Only calling `Thread.Sleep' when no data is available.

   * Improved escaping of quote characters in parameter data.

   * Removed misleading comments from `parameter.cs'.

   * Fixed pooling bug.

   * Fixed `ConnectionString' editor dialog (thanks marco p (pomarc)).

   * `UserId' now supported in connection strings (thanks Jeff Neeley).

   * Attempting to create a parameter that is not input throws an
     exception (thanks Ryan Gregg).

   * Added much documentation.

   * Checked in new `MultiHostStream' capability.  Big thanks to Dan
     Guisinger for this. he originally submitted the code and idea of
     supporting multiple machines on the connect string.

   * Added a lot of documentation.

   * Fixed speed issue with 0.73.

   * Changed to Thread.Sleep(0) in MySqlDataStream to help optimize the
     case where it doesn't need to wait (thanks Todd German).

   * Prepopulating the idlepools to `MinPoolSize'.

   * Fixed `MySqlPool' deadlock condition as well as stupid bug where
     CreateNewPooledConnection was not ever adding new connections to
     the pool. Also fixed `MySqlStream.ReadBytes' and `ReadByte' to not
     use `TicksPerSecond' which does not appear to always be right.
     (thanks Matthew J. Peddlesden)

   * Fix for precision and scale (thanks Matthew J. Peddlesden).

   * Added `Thread.Sleep(1)' to stream reading methods to be more cpu
     friendly (thanks Sean McGinnis).

   * Fixed problem where `ExecuteReader' would sometime return null
     (thanks Lloyd Dupont).

   * Fixed major bug with null field handling (thanks Naucki).

   * Enclosed queries for `max_allowed_packet' and `characterset'
     inside try catch (and set defaults).

   * Fixed problem where socket was not getting closed properly (thanks
     Steve!).

   * Fixed problem where `ExecuteNonQuery' was not always returning the
     right value.

   * Fixed `InternalConnection' to not use
     `@@session.max_allowed_packet' but use `@@max_allowed_packet'.
     (Thanks Miguel)

   * Added many new XML doc lines.

   * Fixed SQL parsing to not send empty queries (thanks Rory).

   * Fixed problem where the reader was not unpeeking the packet on
     close.

   * Fixed problem where user variables were not being handled (thanks
     Sami Vaaraniemi).

   * Fixed loop checking in the MySqlPool (thanks Steve M. Brown)

   * Fixed `ParameterCollection.Add' method to match `SqlClient'
     (thanks Joshua Mouch).

   * Fixed `ConnectionString' parsing to handle no and yes for boolean
     and not lowercase values (thanks Naucki).

   * Added `InternalConnection' class, changes to pooling.

   * Implemented Persist Security Info.

   * Added `security.cs' and `version.cs' to project

   * Fixed `DateTime' handling in `Parameter.cs' (thanks Burkhard
     Perkens-Golomb).

   * Fixed parameter serialization where some types would throw a cast
     exception.

   * Fixed `DataReader' to convert all returned values to prevent
     casting errors (thanks Keith Murray).

   * Added code to `Command.ExecuteReader' to return null if the
     initial SQL statement throws an exception (thanks Burkhard
     Perkens-Golomb).

   * Fixed `ExecuteScalar' bug introduced with restructure.

   * Restructure to permit `LOCAL DATA INFILE' and better sequencing of
     packets.

   * Fixed several bugs related to restructure.

   * Early work done to support more secure passwords in MySQL 4.1.
     Old passwords in 4.1 not supported yet.

   * Parameters appearing after system parameters are now handled
     correctly (Adam M. (adammil)).

   * Strings can now be assigned directly to blob fields (Adam M.).

   * Fixed float parameters (thanks Pent).

   * Improved Parameter constructor and `ParameterCollection.Add'
     methods to better match SqlClient (thanks Joshua Mouch).

   * Corrected `Connection.CreateCommand' to return a `MySqlCommand'
     type.

   * Fixed connection string designer dialog box problem (thanks
     Abraham Guyt).

   * Fixed problem with sending commands not always reading the
     response packet (thanks Joshua Mouch).

   * Fixed parameter serialization where some blobs types were not
     being handled (thanks Sean McGinnis).

   * Removed spurious `MessageBox.show' from `DataReader' code (thanks
     Joshua Mouch).

   * Fixed a nasty bug in the split SQL code (thanks everyone!).


File: manual.info,  Node: connector-net-news-0-71,  Next: connector-net-news-0-70,  Prev: connector-net-news-0-74,  Up: connector-net-news

D.4.15 Changes in MySQL Connector/Net Version 0.71
--------------------------------------------------

   * Fixed bug in `MySqlStream' where too much data could attempt to be
     read (thanks Peter Belbin)

   * Implemented `HasRows' (thanks Nash Pherson).

   * Fixed bug where tables with more than 252 columns cause an
     exception (thanks Joshua Kessler).

   * Fixed bug where SQL statements ending in ; would cause a problem
     (thanks Shane Krueger).

   * Fixed bug in driver where error messages were getting truncated by
     1 character (thanks Shane Krueger).

   * Made `MySqlException' serializable (thanks Mathias Hasselmann).


File: manual.info,  Node: connector-net-news-0-70,  Next: connector-net-news-0-68,  Prev: connector-net-news-0-71,  Up: connector-net-news

D.4.16 Changes in MySQL Connector/Net Version 0.70
--------------------------------------------------

   * Updated some of the character code pages to be more accurate.

   * Fixed problem where readers could be opened on connections that
     had readers open.

   * Moved test to separate assembly `MySqlClientTests'.

   * Fixed stupid problem in driver with sequence out of order (Thanks
     Peter Belbin).

   * Added some pipe tests.

   * Increased default max pool size to 50.

   * Compiles with Mono 0-24.

   * Fixed connection and data reader dispose problems.

   * Added `String' data type handling to parameter serialization.

   * Fixed sequence problem in driver that occurred after thrown
     exception (thanks Burkhard Perkens-Golomb).

   * Added support for `CommandBehavior.SingleRow' to `DataReader'.

   * Fixed command SQL processing so quotation marks are better handled
     (thanks Theo Spears).

   * Fixed parsing of double, single, and decimal values to account for
     non-English separators. You still have to use the right syntax if
     you using hard coded SQL, but if you use parameters the code will
     convert floating point types to use '.'  appropriately internal
     both into the server and out.

   * Added `MySqlStream' class to simplify timeouts and driver coding.

   * Fixed `DataReader' so that it is closed properly when the
     associated connection is closed. [thanks smishra]

   * Made client more SqlClient compliant so that DataReaders have to
     be closed before the connection can be used to run another command.

   * Improved `DBNull.Value' handling in the fields.

   * Added several unit tests.

   * Fixed `MySqlException' base class.

   * Improved driver coding

   * Fixed bug where NextResult was returning false on the last
     resultset.

   * Added more tests for MySQL.

   * Improved casting problems by equating unsigned 32bit values to
     Int64 and unsigned 16bit values to Int32, and so forth.

   * Added new constructor for `MySqlParameter' for (name, type, size,
     srccol)

   * Fixed bug in `MySqlDataReader' where it didn't check for null
     fieldlist before returning field count.

   * Started adding `MySqlClient' unit tests (added `MySqlClient/Tests'
     folder and some test cases).

   * Fixed some things in Connection String handling.

   * Moved `INIT_DB' to `MySqlPool'. I may move it again, this is in
     preparation of the conference.

   * Fixed bug inside `CommandBuilder' that prevented inserts from
     happening properly.

   * Reworked some of the internals so that all three execute methods
     of Command worked properly.

   * Fixed many small bugs found during benchmarking.

   * The first cut of `CoonectionPooling' is working. "min pool size"
     and "max pool size" are respected.

   * Work to enable multiple resultsets to be returned.

   * Character sets are handled much more intelligently now. The driver
     queries MySQL at startup for the default character set.  That
     character set is then used for conversions if that code page can
     be loaded. If not, then the default code page for the current OS
     is used.

   * Added code to save the inferred type in the name,value constructor
     of `Parameter'.

   * Also, inferred type if value of null parameter is changed using
     `Value' property.

   * Converted all files to use proper Camel case. MySQL is now MySql
     in all files. PgSQL is now PgSql.

   * Added attribute to PgSql code to prevent designer from trying to
     show.

   * Added `MySQLDbType' property to Parameter object and added proper
     conversion code to convert from `DbType' to `MySQLDbType').

   * Removed unused `ObjectToString' method from `MySQLParameter.cs'.

   * Fixed `Add(..)' method in `ParameterCollection' so that it doesn't
     use `Add(name, value)' instead.

   * Fixed `IndexOf' and `Contains' in `ParameterCollection' to be
     aware that parameter names are now stored without @.

   * Fixed `Command.ConvertSQLToBytes' so it only permits characters
     that can be in MySQL variable names.

   * Fixed `DataReader' and `Field' so that blob fields read their data
     from `Field.cs' and `GetBytes' works right.

   * Added simple query builder editor to `CommandText' property of
     `MySQLCommand'.

   * Fixed `CommandBuilder' and `Parameter' serialization to account for
     Parameters not storing @ in their names.

   * Removed `MySQLFieldType' enum from Field.cs.  Now using
     `MySQLDbType' enum.

   * Added `Designer' attribute to several classes to prevent designer
     view when using VS.Net.

   * Fixed Initial catalog typo in `ConnectionString' designer.

   * Removed 3 parameter constructor for `MySQLParameter' that
     conflicted with (name, type, value).

   * Changed `MySQLParameter' so `paramName' is now stored without
     leading @ (this fixed null inserts when using designer).

   * Changed `TypeConverter' for `MySQLParameter' to use the
     constructor with all properties.


File: manual.info,  Node: connector-net-news-0-68,  Next: connector-net-news-0-65,  Prev: connector-net-news-0-70,  Up: connector-net-news

D.4.17 Changes in MySQL Connector/Net Version 0.68
--------------------------------------------------

   * Fixed sequence issue in driver.

   * Added `DbParametersEditor' to make parameter editing more like
     `SqlClient'.

   * Fixed `Command' class so that parameters can be edited using the
     designer

   * Update connection string designer to support `Use Compression'
     flag.

   * Fixed string encoding so that European characters will work
     correctly.

   * Creating base classes to aid in building new data providers.

   * Added support for UID key in connection string.

   * Field, parameter, command now using DBNull.Value instead of null.

   * `CommandBuilder' using `DBNull.Value'.

   * `CommandBuilder' now builds insert command correctly when an
     auto_insert field is not present.

   * Field now uses typeof keyword to return `System.Types'
     (performance).


File: manual.info,  Node: connector-net-news-0-65,  Next: connector-net-news-0-60,  Prev: connector-net-news-0-68,  Up: connector-net-news

D.4.18 Changes in MySQL Connector/Net Version 0.65
--------------------------------------------------

   * `MySQLCommandBuilder' now implemented.

   * Transaction support now implemented (not all table types support
     this).

   * `GetSchemaTable' fixed to not use xsd (for Mono).

   * Driver is now Mono-compatible.

   * TIME data type now supported.

   * More work to improve Timestamp data type handling.

   * Changed signatures of all classes to match corresponding
     `SqlClient' classes.


File: manual.info,  Node: connector-net-news-0-60,  Next: connector-net-news-0-50,  Prev: connector-net-news-0-65,  Up: connector-net-news

D.4.19 Changes in MySQL Connector/Net Version 0.60
--------------------------------------------------

   * Protocol compression using SharpZipLib (www.icsharpcode.net).

   * Named pipes on Windows now working properly.

   * Work done to improve `Timestamp' data type handling.

   * Implemented `IEnumerable' on `DataReader' so `DataGrid' would work.


File: manual.info,  Node: connector-net-news-0-50,  Prev: connector-net-news-0-60,  Up: connector-net-news

D.4.20 Changes in MySQL Connector/Net Version 0.50
--------------------------------------------------

   * Speed increased dramatically by removing bugging network sync code.

   * Driver no longer buffers rows of data (more ADO.Net compliant).

   * Conversion bugs related to *Note `TIMESTAMP': datetime. and *Note
     `DATETIME': datetime. fields fixed.


File: manual.info,  Node: vstudio-plugin-news,  Next: cj-news,  Prev: connector-net-news,  Up: news

D.5 MySQL Visual Studio Plugin Change History
=============================================

* Menu:

* vstudio-plugin-news-1-0-3::    Changes in MySQL Visual Studio Plugin 1.0.3 (Not yet released)
* vstudio-plugin-news-1-0-2::    Changes in MySQL Visual Studio Plugin 1.0.2 (Not yet released)
* vstudio-plugin-news-1-0-1::    Changes in MySQL Visual Studio Plugin 1.0.1 (04 October 2006)
* vstudio-plugin-news-1-0-0::    Changes in MySQL Visual Studio Plugin 1.0.0 (04 October 2006)

*Note*:

As of Connector/Net 5.1.2 (14 June 2007), the Visual Studion Plugin is
part of the main Connector/Net package. For the change history for the
Visual Studio Plugin, see *Note connector-net-news::.


File: manual.info,  Node: vstudio-plugin-news-1-0-3,  Next: vstudio-plugin-news-1-0-2,  Prev: vstudio-plugin-news,  Up: vstudio-plugin-news

D.5.1 Changes in MySQL Visual Studio Plugin 1.0.3 (Not yet released)
--------------------------------------------------------------------

*Bugs Fixed*

   * Running queries based on a stored procedure would cause the data
     set designer to terminate. (Bugs #26364)

   * DataSet wizard would show all tables instead of only the tables
     available within the selected database. (Bugs #26348)


File: manual.info,  Node: vstudio-plugin-news-1-0-2,  Next: vstudio-plugin-news-1-0-1,  Prev: vstudio-plugin-news-1-0-3,  Up: vstudio-plugin-news

D.5.2 Changes in MySQL Visual Studio Plugin 1.0.2 (Not yet released)
--------------------------------------------------------------------

*Bugs Fixed*

   * The Add Connection dialog of the Server Explorer would freeze when
     accessing databases with capitalized characters in their name.
     (Bug #24875)

   * Creating a connection through the Server Explorer when using the
     Visual Studio Plugin would fail. The installer for the Visual
     Studio Plugin has been updated to ensure that Connector/Net 5.0.2
     must be installed.  (Bug #23071)


File: manual.info,  Node: vstudio-plugin-news-1-0-1,  Next: vstudio-plugin-news-1-0-0,  Prev: vstudio-plugin-news-1-0-2,  Up: vstudio-plugin-news

D.5.3 Changes in MySQL Visual Studio Plugin 1.0.1 (04 October 2006)
-------------------------------------------------------------------

This is a bug fix release to resolve an incompatibility issue with
Connector/Net 5.0.1.

It is critical that this release only be used with Connector/Net 5.0.1.
After installing Connector/Net 5.0.1, you will need to make a small
change in your machine.config file. This file should be located at
`%win%\Microsoft.Net\Framework\v2.0.50727\CONFIG\machine.config'
(`%win%' should be the location of your Windows folder). Near the
bottom of the file you will see a line like this:

     <add name="MySQL Data Provider" invariant="MySql.Data.MySqlClient"
     description=".Net Framework Data Provider for MySQL"
     type="MySql.Data.MySqlClient.MySqlClientFactory, MySql.Data"/>

It needs to be changed to be like this:

     <add name="MySQL Data Provider" invariant="MySql.Data.MySqlClient"
     description=".Net Framework Data Provider for MySQL"
     type="MySql.Data.MySqlClient.MySqlClientFactory, MySql.Data,
     Version=5.0.1.0, Culture=neutral, PublicKeyToken=c5687fc88969c44d"/>

This section has no changelog entries.


File: manual.info,  Node: vstudio-plugin-news-1-0-0,  Prev: vstudio-plugin-news-1-0-1,  Up: vstudio-plugin-news

D.5.4 Changes in MySQL Visual Studio Plugin 1.0.0 (04 October 2006)
-------------------------------------------------------------------

*Bugs Fixed*

   * Ability to work with MySQL objects (tables, views, stored
     procedures, etc) from within Server Explorer.

   * DDEX (Data Designer Extensibility) compatibility.


File: manual.info,  Node: cj-news,  Next: news-connector-mxj,  Prev: vstudio-plugin-news,  Up: news

D.6 MySQL Connector/J Change History
====================================

* Menu:

* cj-news-5-1-x::                Changes in MySQL Connector/J 5.1.x
* cj-news-5-0-x::                Changes in MySQL Connector/J 5.0.x
* cj-news-3-1-x::                Changes in MySQL Connector/J 3.1.x
* cj-news-3-0-x::                Changes in MySQL Connector/J 3.0.x
* cj-news-2-0-x::                Changes in MySQL Connector/J 2.0.x
* cj-news-1-2-x::                Changes in MySQL Connector/J 1.2.x and lower


File: manual.info,  Node: cj-news-5-1-x,  Next: cj-news-5-0-x,  Prev: cj-news,  Up: cj-news

D.6.1 Changes in MySQL Connector/J 5.1.x
----------------------------------------

* Menu:

* cj-news-5-1-18::               Changes in MySQL Connector/J 5.1.18 (04 October 2011)
* cj-news-5-1-17::               Changes in MySQL Connector/J 5.1.17 (07 July 2011)
* cj-news-5-1-16::               Changes in MySQL Connector/J 5.1.16 (Not released)
* cj-news-5-1-15::               Changes in MySQL Connector/J 5.1.15 (09 February 2011)
* cj-news-5-1-14::               Changes in MySQL Connector/J 5.1.14 (6th December 2010)
* cj-news-5-1-13::               Changes in MySQL Connector/J 5.1.13 (24 June 2010)
* cj-news-5-1-12::               Changes in MySQL Connector/J 5.1.12 (18 February 2010)
* cj-news-5-1-11::               Changes in MySQL Connector/J 5.1.11 (21 January 2010)
* cj-news-5-1-10::               Changes in MySQL Connector/J 5.1.10 (23 September 2009)
* cj-news-5-1-9::                Changes in MySQL Connector/J 5.1.9 (21 September 2009)
* cj-news-5-1-8::                Changes in MySQL Connector/J 5.1.8 (16 July 2009)
* cj-news-5-1-7::                Changes in MySQL Connector/J 5.1.7 (21 October 2008)
* cj-news-5-1-6::                Changes in MySQL Connector/J 5.1.6 (07 March 2008)
* cj-news-5-1-5::                Changes in MySQL Connector/J 5.1.5 (09 October 2007)
* cj-news-5-1-4::                Changes in MySQL Connector/J 5.1.4 (Not Released)
* cj-news-5-1-3::                Changes in MySQL Connector/J 5.1.3 (10 September 2007)
* cj-news-5-1-2::                Changes in MySQL Connector/J 5.1.2 (29 June 2007)
* cj-news-5-1-1::                Changes in MySQL Connector/J 5.1.1 (22 June 2007)
* cj-news-5-1-0::                Changes in MySQL Connector/J 5.1.0 (11 April 2007)


File: manual.info,  Node: cj-news-5-1-18,  Next: cj-news-5-1-17,  Prev: cj-news-5-1-x,  Up: cj-news-5-1-x

D.6.1.1 Changes in MySQL Connector/J 5.1.18 (04 October 2011)
.............................................................

Fixes bugs found since release 5.1.17.

*Functionality Added or Changed*

   * Added the function `MYSQL_INDEX_TO_MYSQL_CHARSET' to retrieve the
     server charset name, using an index instead of parsing variables
     to `CharsetMapping.java'

*Bugs Fixed*

   * The `LRUCache' implementation removed the eldest entry, rather
     than the least-recently accessed.  (Bug #13036537)

   * Changed `cacheCallableStatements' to `cacheCallableStmts' in
     `maxPerformance.properties', to allow proper caching.  (Bug
     #13036309)

   * Added a new `ant' flag, `com.mysql.jdbc.junit.fork', which controls
     whether `JUnit' will fork new processes.

     The value `on': The default, and legacy behavior. Or `off'):
     Required for Windows, as otherwise `process fork failure' errors
     will result while running the test suite via `ant' on Windows.
     (Bug #12784170)

   * Not putting a space between `VALUES()' and *Note `ON DUPLICATE KEY
     UPDATE': insert-on-duplicate. causes connector/J to both (A)
     Rewrite the query, although it includes an `ON UPDATE' statment
     and (B) To generate the wrong query with multiple *Note `ON
     DUPLICATE KEY': insert-on-duplicate. statements.  (Bug #12565726)

   * The "old" warnings were returned when `Statement.getWarnings()'
     was called after `Statement.clearWarnings()'.  (Bug #61866, Bug
     #12791594)

   * Calling `Statement.cancel()' on a statement that isn't currently
     executing, will cause a later-executed query on the same
     connection to be unexpectedly canceled. The driver now guards
     against this condition, but it is an underlying server issue. The
     MySQL statement *Note `KILL QUERY': kill.  (which is what the
     driver uses to implement `Statement.cancel()') is rather
     non-deterministic, and thus the use of `Statement.cancel()' should
     be avoided if possible.  (Bug #61501)

   * A connection could not be established when the URL contained both
     `sessionVariables' and `characterEncoding'.  (Bug #61201, Bug
     #12649557)

   * Reverting changes made to `ConnectionImpl.java', the `private
     boolean characterSetNamesMatches' function.


File: manual.info,  Node: cj-news-5-1-17,  Next: cj-news-5-1-16,  Prev: cj-news-5-1-18,  Up: cj-news-5-1-x

D.6.1.2 Changes in MySQL Connector/J 5.1.17 (07 July 2011)
..........................................................

Fixes bugs found since release 5.1.16.

*Bugs Fixed*

   * `LIKE' was not optimized in then server when run against
     `INFORMATION_SCHEMA' tables and no wildcards were used.
     Databases/tables with `'_'' or `'%'' in their names (escaped or
     not) are handled by this code path, although slower, since it is
     rare to find these characters in table names in SQL.  If there is
     a `'_'' or `'%'' in the string, `LIKE' takes care of that;
     otherwise, `'='' is now used instead. The only exception is the
     `information_schema' database, which is handled separately. The
     patch covers both `getTables()' and `getColumns()'.  (Bug #61332)

   * The first call to a stored procedure failed with `No Database
     Selected'. The workaround introduced in
     `DatabaseMetaData.getCallStmtParameterTypes' to fix the server bug
     where *Note `SHOW CREATE PROCEDURE': show-create-procedure. was
     not respecting lowercase table names was misbehaving when the
     connection was not attached to a database and on case-insensitive
     operating systems.  (Bug #61150)

   * There was a concurrency bottleneck in Java's character set
     encoding/decoding when converting bytes to/from `String' values.

     *Important*:

     No longer use `String.getBytes(...)', or `new String(byte[]...)'.
     Use the `StringUtils' method instead.

     (Bug #61105)


File: manual.info,  Node: cj-news-5-1-16,  Next: cj-news-5-1-15,  Prev: cj-news-5-1-17,  Up: cj-news-5-1-x

D.6.1.3 Changes in MySQL Connector/J 5.1.16 (Not released)
..........................................................

Fixes bugs found since release 5.1.15.

*Functionality Added or Changed*

   * The `Connection.isServerLocal()' method can now determine if a
     connection is against a server on the same host.

*Bugs Fixed*

   * When auto-reconnect was used with `cacheServerConfiguration',
     errors could occur when the host changed (in an HA setup, for
     example).  (Bug #12325877)

   * `DBMD.getTables' and `getColumns' fail with table names that
     contain a dot (like "`junk_[Sp:e,c/ C-h+a=.r]'"). The workaround
     is to use `useInformationSchema=True'.  (Bug #11782297)

   * Fixed a timestamp offset bug in
     `com.mysql.jdbc.ResultSetRow.getTimestampFast()'.  (Bug #60313,
     Bug #11890729)

   * `wasNull' was not set for a `DATE' field with the value of
     `0000-00-00' in `getDate()', although `zeroDateTimeBehavior' is
     defined as `convertToNull'.  (Bug #57808)

   * A bypassing of the server protocol bug, where the DB should be
     null-terminated whether it exists or not. This affects
     `COM_CHANGE_USER'.  (Bug #54425)

   * Fixed a bug where Connector/J would kill the matching
     `ConnectionID', but on the wrong server.  (Bug #54135)


File: manual.info,  Node: cj-news-5-1-15,  Next: cj-news-5-1-14,  Prev: cj-news-5-1-16,  Up: cj-news-5-1-x

D.6.1.4 Changes in MySQL Connector/J 5.1.15 (09 February 2011)
..............................................................

Fixes bugs found since release 5.1.14.

*Bugs Fixed*

   * Optional logging class `com.mysql.jdbc.log.Log4JLogger' was not
     included in the source/binary package for 5.1.14.

     5.1.15 will ship with an SLF4J logger (which can then be plugged
     into Log4J). Unfortunately, it is not possible to ship a direct
     Log4J integration because the GPL is not compatible with Log4J's
     license.  (Bug #59511, Bug #11766408)

   * The hard-coded list of reserved words in Connector/J was not
     updated to reflect the list of reserved words in MySQL Server 5.5.
     (Bug #59224)

   * MySqlProcedure accepted null arguments as parameters, however the
     JDBC meta data did not indicate that.  (Bug #38367, Bug #11749186)

   * Using Connector/J to connect from a z/OS machine to a MySQL Server
     failed when the database name to connect to was included in the
     connection URL. This was because the name was sent in z/OS default
     platform encoding, but the MySQL Server expected Latin1.

     It should be noted that when connecting from systems that do not
     use Latin1 as the default platform encoding, the following
     connection string options can be useful:
     `passwordCharacterEncoding=ASCII' and `characterEncoding=ASCII'.
     (Bug #18086, Bug #11745647)


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D.6.1.5 Changes in MySQL Connector/J 5.1.14 (6th December 2010)
...............................................................

Fixes bugs found since release 5.1.13.

*Functionality Added or Changed*

   * Connector/J's load-balancing functionality only allowed the
     following events to trigger failover:

        * Transaction commit/rollback

        * CommunicationExceptions

        * Matches to user-defined Exceptions using the
          loadBalanceSQLStateFailover,
          loadBalanceSQLExceptionSubclassFailover or
          loadBalanceExceptionChecker property.

     This meant that connections where auto-commit was enabled were not
     balanced, except for Exceptions, and this was problematic in the
     case of distribution of read-only work across slaves in a
     replication deployment.

     The ability to load-balance while auto-commit is enabled has now
     been added to Connector/J. This introduces two new properties:

       1. loadBalanceAutoCommitStatementThreshold - defines the number
          of matching statements which will trigger the driver to
          (potentially) swap physical server connections. The default
          value (0) retains the previously-established behavior that
          connections with auto-commit enabled are never balanced.

       2. loadBalanceAutoCommitStatementRegex - the regular expression
          against which statements must match. The default value
          (blank) matches all statements.

     Load-balancing will be done after the statement is executed,
     before control is returned to the application. If rebalancing
     fails, the driver will silently swallow the resulting Exception
     (as the statement itself completed successfully).  (Bug #55723)

*Bugs Fixed*

   * Connection failover left slave/secondary in read-only mode.
     Failover attempts between two read-write masters did not properly
     set `this.currentConn.setReadOnly(false)'.  (Bug #58706)

   * Connector/J mapped both 3-byte and 4-byte UTF8 encodings to the
     same Java UTF8 encoding.

     To use 3-byte UTF8 with Connector/J set `characterEncoding=utf8'
     and set `useUnicode=true' in the connection string.

     To use 4-byte UTF8 with Connector/J configure the MySQL server
     with `character_set_server=utf8mb4'.  Connector/J will then use
     that setting as long as `characterEncoding' has not been set in the
     connection string. This is equivalent to autodetection of the
     character set.  (Bug #58232)

   * The `CallableStatementRegression' test suite failed with a Null
     Pointer Exception because the `OUT' parameter in the
     `I__S.PARAMETERS' table had no name, that is `COLUMN_NAME' had the
     value `NULL'.  (Bug #58232)

   * `DatabaseMetaData.supportsMultipleResultSets()' was hard-coded to
     return `false', even though Connector/J supports multiple result
     sets.  (Bug #57380)

   * Using the `useOldUTF8Behavior' parameter failed to set the
     connection character set to `latin1' as required.

     In versions prior to 5.1.3, the handshake was done using `latin1',
     and while there was logic in place to explicitly set the character
     set after the handshake was complete, this was bypassed when
     `useOldUTF8Behavior' was true. This was not a problem until 5.1.3,
     when the handshake was modified to use `utf8', but the logic
     continued to allow the character set configured during that
     handshake process to be retained for later use. As a result,
     `useOldUTF8Behavior' effectively failed.  (Bug #57262)

   * Invoking a stored procedure containing output parameters by its
     full name, where the procedure was located in another database,
     generated the following exception:

          Parameter index of 1 is out of range (1, 0)

     (Bug #57022)

   * When a JDBC client disconnected from a remote server using
     `Connection.close()', the TCP connection remained in the
     `TIME_WAIT' state on the server side, rather than on the client
     side.  (Bug #56979)

   * Leaving Trust/ClientCertStoreType properties unset caused an
     exception to be thrown when connecting with `useSSL=true', as no
     default was used.  (Bug #56955)

   * When load-balanced connections swap servers, certain session state
     was copied from the previously active connection to the
     newly-selected connection. State synchronized included:

        * Auto-commit state

        * Transaction isolation state

        * Current schema/catalog

     However, the read-only state was not synchronized, which caused
     problems if a write was attempted on a read-only connection.  (Bug
     #56706)

   * When using Connector/J configured for failover
     (jdbc:mysql://host1,host2,... URLs), the non-primary servers
     re-balanced when the transactions on the master were committed or
     rolled-back.  (Bug #56429)

   * An unhandled Null Pointer Exception (NPE) was generated in
     `DatabaseMetaData.java' when calling an incorrectly cased function
     name where no permission to access `mysql.proc' was available.

     In addition to catching potential NPEs, a guard against calling
     JDBC functions with `db_name.proc_name' notation was also added.
     (Bug #56305)

   * Attempting to use JDBC4 functions on `Connection' objects resulted
     in errors being generated:

          Exception in thread "main" java.lang.AbstractMethodError:
          com.mysql.jdbc.LoadBalancedMySQLConnection.createBlob()Ljava/sql/Blob;
             at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
             at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39)
             at
          sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
             at java.lang.reflect.Method.invoke(Method.java:597)
             at
          com.mysql.jdbc.LoadBalancingConnectionProxy.invoke(LoadBalancingConnectionProxy.java:476)
             at $Proxy0.createBlob(Unknown Source)

     (Bug #56099)


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D.6.1.6 Changes in MySQL Connector/J 5.1.13 (24 June 2010)
..........................................................

Fixes bugs found since release 5.1.12.

*Functionality Added or Changed*

   * Connector/J did not support `utf8mb4' for servers 5.5.2 and newer.

     Connector/J now auto-detects servers configured with
     `character_set_server=utf8mb4' or treats the Java encoding `utf-8'
     passed using `characterEncoding=...' as `utf8mb4' in the `SET
     NAMES=' calls it makes when establishing the connection.  (Bug
     #54175)

*Bugs Fixed*

   * The method `unSafeStatementInterceptors()' contained an erroneous
     line of code, which resulted in the interceptor being called, but
     the result being thrown away.  (Bug #53041)

   * There was a performance regression of roughly 25% between r906 and
     r907, which appeared to be caused by pushing the Proxy down to the
     I/O layer.  (Bug #52534)

   * Logic in implementations of `LoadBalancingConnectionProxy' and
     `LoadBalanceStrategy' behaved differently as to which
     `SQLException's trigger failover to a new host. The former looked
     at the first two characters of the SQLState:

          if (sqlState.startsWith("08"))
          ...

     The latter used a different test:

          if (sqlEx instanceof CommunicationsException
            || "08S01".equals(sqlEx.getSQLState())) {
          ...

     This meant it was possible for a new `Connection' object to throw
     an `Exception' when the first selected host was unavailable. This
     happened because `MySqlIO.createNewIO()' could throw an
     `SQLException' with a `SQLState' of `08001', which did not trigger
     the `try another host' logic in the `LoadBalanceStrategy'
     implementations, so an `Exception' was thrown after having only
     attempted connecting to a single host.  (Bug #52231)

   * In the file `DatabaseMetadata.java', the function `private void
     getCallStmtParameterTypes' failed if the parameter was defined
     over more than one line by using the '\n' character.  (Bug #52167)

   * The catalog parameter, `PARAM_CAT', was not correctly processed
     when calling for metadata with `getMetaData()' on stored
     procedures. This was because `PARAM_CAT' was hardcoded in the code
     to `NULL'. In the case where `nullcatalogmeanscurrent' was `true',
     which is its default value, a crash did not occur, but the
     metadata returned was for the stored procedures from the catalog
     currently attached to. If, however, `nullcatalogmeanscurrent' was
     set to `false' then a crash resulted.

     Connector/J has been changed so that when `NULL' is passed as
     `PARAM_CAT' it will not crash when `nullcatalogmeanscurrent' is
     `false', but rather iterate all catalogs in search of stored
     procedures. This means that `PARAM_CAT' is no longer hardcoded to
     `NULL' (see Bug #51904).  (Bug #51912)

   * A load balanced `Connection' object with multiple open underlying
     physical connections rebalanced on `commit()', `rollback()', or on
     a communication exception, without validating the existing
     connection. This caused a problem when there was no pinging of the
     physical connections, using queries starting with `/* ping */', to
     ensure they remained active. This meant that calls to
     `Connection.commit()' could throw a `SQLException'. This did not
     occur when the transaction was actually committed; it occurred
     when the new connection was chosen and the driver attempted to set
     the auto-commit or transaction isolation state on the newly chosen
     physical connection.  (Bug #51783)

   * The `rollback()' method could fail to rethrow a `SQLException' if
     the server became unavailable during a rollback. The errant code
     only rethrew when `ignoreNonTxTables' was true and the exception
     did not have the error code 1196,
     `SQLError.ER_WARNING_NOT_COMPLETE_ROLLBACK'.  (Bug #51776)

   * When the `allowMultiQueries' connection string option was set to
     `true', a call to `Statement.executeBatch()' scanned the query for
     escape codes, even though `setEscapeProcessing(false)' had been
     called previously.  (Bug #51704)

   * When a `StatementInterceptor' was used and an alternate
     `ResultSet' was returned from `preProcess()', the original
     statement was still executed.  (Bug #51666)

   * Objects created by `ConnectionImpl', such as prepared statements,
     hold a reference to the `ConnectionImpl' that created them.
     However, when the load balancer picked a new connection, it did not
     update the reference contained in, for example, the
     `PreparedStatement'. This resulted in inserts and updates being
     directed to invalid connections, while commits were directed to
     the new connection. This resulted in silent data loss.  (Bug
     #51643)

   * `jdbc:mysql:loadbalance://' would connect to the same host, even
     though `loadBalanceStrategy' was set to a value of `random', and
     multiple hosts were specified.  (Bug #51266)

   * An unexpected exception when trying to register `OUT' parameters in
     `CallableStatement'.

     Sometimes Connector/J was not able to register `OUT' parameters for
     `CallableStatements'.  (Bug #43576)


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D.6.1.7 Changes in MySQL Connector/J 5.1.12 (18 February 2010)
..............................................................

Fixes bugs found since release 5.1.11.

*Bugs Fixed*

   * The catalog parameter was ignored in the
     `DatabaseMetaData.getProcedure()' method. It returned all
     procedures in all databases.  (Bug #51022)

   * A call to `DatabaseMetaData.getDriverVersion()' returned the
     revision as `mysql-connector-java-5.1.11 ( Revision:
     ${svn.Revision} )'. The variable `${svn.Revision}' was not
     replaced by the SVN revision number.  (Bug #50288)


File: manual.info,  Node: cj-news-5-1-11,  Next: cj-news-5-1-10,  Prev: cj-news-5-1-12,  Up: cj-news-5-1-x

D.6.1.8 Changes in MySQL Connector/J 5.1.11 (21 January 2010)
.............................................................

Fixes bugs found since release 5.1.10.

*Functionality Added or Changed*

   * Replication connections, those with URLs that start with
     jdbc:mysql:replication, now use a jdbc:mysql:loadbalance
     connection for the slave pool. This means that it is possible to
     set load balancing properties such as
     `loadBalanceBlacklistTimeout' and `loadBalanceStrategy' to choose
     a mechanism for balancing the load, and failover or fault
     tolerance strategy for the slave pool.  (Bug #49537)

*Bugs Fixed*

   * `NullPointerException' sometimes occurred in
     `invalidateCurrentConnection()' for load-balanced connections.
     (Bug #50288)

   * The `deleteRow' method caused a full table scan, when using an
     updatable cursor and a multibyte character set.  (Bug #49745)

   * For pooled connections, Connector/J did not process the session
     variable `time_zone' when set using the URL, resulting in
     incorrect timestamp values being stored.  (Bug #49700)

   * The `ExceptionInterceptor' class did not provide a `Connection'
     context.  (Bug #49607)

   * Ping left closed connections in the liveConnections map, causing
     subsequent Exceptions when that connection was used.  (Bug #48605)

   * Using `MysqlConnectionPoolDataSource' with a load-balanced URL
     generated exceptions of type `ClassCastException':

          ClassCastException in MysqlConnectionPoolDataSource
          Caused by: java.lang.ClassCastException: $Proxy0
             at
          com.mysql.jdbc.jdbc2.optional.MysqlConnectionPoolDataSource.getPooledConnection(MysqlConne
          ctionPoolDataSource.java:80)

          java.lang.ClassCastException: $Proxy2
           at com.mysql.jdbc.jdbc2.optional.StatementWrapper.executeQuery(StatementWrapper.java:744)

     (Bug #48486)

   * The implementation for load-balanced `Connection' used a proxy,
     which delegated method calls, including `equals()' and
     `hashCode()', to underlying `Connection' objects. This meant that
     successive calls to `hashCode()' on the same object potentially
     returned different values, if the proxy state had changed such
     that it was utilizing a different underlying connection.  (Bug
     #48442)

   * The batch rewrite functionality attempted to identify the start of
     the `VALUES' list by looking for `VALUES ' (with trailing space).
     However, valid MySQL syntax permits `VALUES' to be followed by
     whitespace or an opening parenthesis:

          INSERT INTO tbl VALUES
          (1);

          INSERT INTO tbl VALUES(1);

     Queries written with the above formats did not therefore gain the
     performance benefits of the batch rewrite.  (Bug #48172)

   * A PermGen memory leaked was caused by the Connector/J statement
     cancellation timer (`java.util.Timer'). When the application was
     unloaded the cancellation timer did not terminate, preventing the
     ClassLoader from being garbage collected.  (Bug #36565)

   * With the connection string option `noDatetimeStringSync' set to
     `true', and server-side prepared statements enabled, the following
     exception was generated if an attempt was made to obtain, using
     `ResultSet.getString()', a datetime value containing all zero
     components:

          java.sql.SQLException: Value '0000-00-00' can not be represented as java.sql.Date

     (Bug #32525)


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D.6.1.9 Changes in MySQL Connector/J 5.1.10 (23 September 2009)
...............................................................

Fixes bugs found since release 5.1.9.

*Bugs Fixed*

   * The `DriverManager.getConnection()' method ignored a non-standard
     port if it was specified in the JDBC connection string.
     Connector/J always used the standard port 3306 for connection
     creation. For example, if the string was
     `jdbc:mysql://localhost:6777', Connector/J would attempt to
     connect to port 3306, rather than 6777.  (Bug #47494)


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D.6.1.10 Changes in MySQL Connector/J 5.1.9 (21 September 2009)
...............................................................

*Bugs Fixed*

   * In the class
     `com.mysql.jdbc.jdbc2.optional.SuspendableXAConnection', which is
     used when `pinGlobalTxToPhysicalConnection=true', there is a
     static map (XIDS_TO_PHYSICAL_CONNECTIONS) that tracks the Xid with
     the XAConnection, however this map was not populated.  The effect
     was that the `SuspendableXAConnection' was never pinned to the
     real XA connection. Instead it created new connections on calls to
     `start', `end', `resume', and `prepare'.  (Bug #46925)

   * When using the ON DUPLICATE KEY UPDATE functionality together with
     the rewriteBatchedStatements option set to true, an exception was
     generated when trying to execute the prepared statement:

          INSERT INTO config_table (modified,id_) VALUES (?,?) ON DUPLICATE KEY UPDATE modified=?

     The exception generated was:

          java.sql.SQLException: Parameter index out of range (3 > number of parameters, which is
          2).
            at com.sag.etl.job.processors.JdbcInsertProcessor.flush(JdbcInsertProcessor.java:135)
          ......
          Caused by: java.sql.SQLException: Parameter index out of range (3 > number of parameters,
          which is 2).
            at com.mysql.jdbc.SQLError.createSQLException(SQLError.java:1055)
            at com.mysql.jdbc.SQLError.createSQLException(SQLError.java:956)
            at com.mysql.jdbc.SQLError.createSQLException(SQLError.java:926)
            at com.mysql.jdbc.PreparedStatement.checkBounds(PreparedStatement.java:3657)
            at com.mysql.jdbc.PreparedStatement.setInternal(PreparedStatement.java:3641)
            at
          com.mysql.jdbc.PreparedStatement.setBytesNoEscapeNoQuotes(PreparedStatement.java:3391)
            at
          com.mysql.jdbc.PreparedStatement.setOneBatchedParameterSet(PreparedStatement.java:4203)
            at com.mysql.jdbc.PreparedStatement.executeBatchedInserts(PreparedStatement.java:1759)
            at com.mysql.jdbc.PreparedStatement.executeBatch(PreparedStatement.java:1441)
            at com.sag.etl.job.processors.JdbcInsertProcessor.flush(JdbcInsertProcessor.java:131)
            ... 16 more

     (Bug #46788)

   * When Connector/J encountered an error condition that caused it to
     create a `CommunicationsException', it tried to build a friendly
     error message that helped diagnose what was wrong. However, if
     there had been no network packets received from the server, the
     error message contained the following incorrect text:

          The last packet successfully received from the server was 1,249,932,468,916 milliseconds
          ago.  The last packet sent successfully to the server was 0 milliseconds ago.

     (Bug #46637)

   * The `getSuperTypes' method returned a result set with incorrect
     names for the first two columns. The name of the first column in
     the result set was expected to be `TYPE_CAT' and that of the
     second column `TYPE_SCHEM'. The method however returned the names
     as `TABLE_CAT' and `TABLE_SCHEM' for first and second column
     respectively.  (Bug #44508)

   * SQLException for data truncation error gave the error code as 0
     instead of 1265.  (Bug #44324)

   * Calling `ResultSet.deleteRow()' on a table with a primary key of
     type `BINARY(8)' silently failed to delete the row, but only in
     some repeatable cases. The generated `DELETE' statement generated
     corrupted part of the primary key data. Specifically, one of the
     bytes was changed from 0x90 to 0x9D, although the corruption
     appeared to be different depending on whether the application was
     run on Windows or Linux.  (Bug #43759)

   * Accessing result set columns by name after the result set had been
     closed resulted in a NullPointerException instead of a
     SQLException.  (Bug #41484)

   * `QueryTimeout' did not work for batch statements waiting on a
     locked table.

     When a batch statement was issued to the server and was forced to
     wait because of a locked table, Connector/J only terminated the
     first statement in the batch when the timeout was exceeded,
     leaving the rest hanging.  (Bug #34555)

   * The `parseURL' method in class `com.mysql.jdbc.Driver' did not
     work as expected. When given a URL such as
     `jdbc:mysql://www.mysql.com:12345/my_database' to parse, the
     property `PORT_PROPERTY_KEY' was found to be `null' and the
     `HOST_PROPERTY_KEY' property was found to be `www.mysql.com:12345'.

     *Note*:

     Connector/J has been fixed so that it will now always fill in the
     `PORT' property (using 3306 if not specified), and the `HOST'
     property (using `localhost' if not specified) when `parseURL()' is
     called. The driver also parses a list of hosts into `HOST.n' and
     `PORT.n' properties as well as adding a property `NUM_HOSTS' for
     the number of hosts it has found. If a list of hosts is passed to
     the driver, `HOST' and `PORT' will be set to the values given by
     `HOST.1' and `PORT.1' respectively. This change has centralized
     and cleaned up a large section of code used to generate lists of
     hosts, both for load-balanced and fault tolerant connections and
     their tests.

     (Bug #32216)

   * Attempting to delete rows using `ResultSet.deleteRow()' did not
     delete rows correctly.  (Bug #27431)

   * The `setDate' method silently ignored the Calendar parameter. The
     code was implemented as follows:

          public void setDate(int parameterIndex, java.sql.Date x, Calendar cal) throws SQLException {
             setDate(parameterIndex, x);
          }

     From reviewing the code it was apparent that the Calendar
     parameter `cal' was ignored.  (Bug #23584)


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D.6.1.11 Changes in MySQL Connector/J 5.1.8 (16 July 2009)
..........................................................

*Bugs Fixed*

   * The reported milliseconds since the last server packets were
     received/sent was incorrect by a factor of 1000. For example, the
     following method call:

          SQLError.createLinkFailureMessageBasedOnHeuristics(
          (ConnectionImpl) this.conn,
          System.currentTimeMillis() - 1000,
          System.currentTimeMillis() - 2000,
          e,
          false);

     returned the following string:

          The last packet successfully received from the server
          was 2 milliseconds ago. The last packet sent successfully to the
          server was 1 milliseconds ago.

     (Bug #45419)

   * Calling `Connection.serverPrepareStatement()' variants that do not
     take result set type or concurrency arguments returned statements
     that produced result sets with incorrect defaults, namely
     `TYPE_SCROLL_SENSITIVE'.  (Bug #45171)

   * The result set returned by `getIndexInfo()' did not have the
     format defined in the JDBC API specifications. The fourth column,
     `DATA_TYPE', of the result set should be of type `BOOLEAN'.
     Connector/J however returns `CHAR'.  (Bug #44869)

   * The result set returned by `getTypeInfo()' did not have the format
     defined in the JDBC API specifications. The second column,
     `DATA_TYPE', of the result set should be of type `INTEGER'.
     Connector/J however returns `SMALLINT'.  (Bug #44868)

   * The `DEFERRABILITY' column in database metadata result sets was
     expected to be of type `SHORT'.  However, Connector/J returned it
     as `INTEGER'.

     This affected the following methods: `getImportedKeys()',
     `getExportedKeys()', `getCrossReference()'.  (Bug #44867)

   * The result set returned by `getColumns()' did not have the format
     defined in the JDBC API specifications. The fifth column,
     `DATA_TYPE', of the result set should be of type `INTEGER'.
     Connector/J however returns `SMALLINT'.  (Bug #44865)

   * The result set returned by `getVersionColumns()' did not have the
     format defined in the JDBC API specifications. The third column,
     `DATA_TYPE', of the result set should be of type `INTEGER'.
     Connector/J however returns `SMALLINT'.  (Bug #44863)

   * The result set returned by `getBestRowIdentifier()' did not have
     the format defined in the JDBC API specifications. The third
     column, `DATA_TYPE', of the result set should be of type
     `INTEGER'. Connector/J however returns `SMALLINT'.  (Bug #44862)

   * Connector/J contains logic to generate a message text specifically
     for streaming result sets when there are `CommunicationsException'
     exceptions generated.  However, this code was never reached.

     In the `CommunicationsException' code:

          private boolean streamingResultSetInPlay = false;

          public CommunicationsException(ConnectionImpl conn, long lastPacketSentTimeMs,
          long lastPacketReceivedTimeMs, Exception underlyingException) {

          this.exceptionMessage = SQLError.createLinkFailureMessageBasedOnHeuristics(conn,
                lastPacketSentTimeMs, lastPacketReceivedTimeMs, underlyingException,
                this.streamingResultSetInPlay);

     `streamingResultSetInPlay' was always false, which in the
     following code in
     `SQLError.createLinkFailureMessageBasedOnHeuristics()' never being
     executed:

          if (streamingResultSetInPlay) {
              exceptionMessageBuf.append(
              Messages.getString("CommunicationsException.ClientWasStreaming")); //$NON-NLS-1$
          } else {
          ...

     (Bug #44588)

   * The `SQLError.createLinkFailureMessageBasedOnHeuristics()' method
     created a message text for communication link failures.  When
     certain conditions were met, this message included both `last
     packet sent' and `last packet received' information, but when
     those conditions were not met, only `last packet sent' information
     was provided.

     Information about when the last packet was successfully received
     should be provided in all cases.  (Bug #44587)

   * `Statement.getGeneratedKeys()' retained result set instances until
     the statement was closed. This caused memory leaks for long-lived
     statements, or statements used in tight loops.  (Bug #44056)

   * Using `useInformationSchema' with
     `DatabaseMetaData.getExportedKeys()' generated the following
     exception:

          com.mysql.jdbc.exceptions.MySQLIntegrityConstraintViolationException: Column
          'REFERENCED_TABLE_NAME' in where clause is ambiguous
          ...
          at com.mysql.jdbc.PreparedStatement.executeInternal(PreparedStatement.java:1772)
          at com.mysql.jdbc.PreparedStatement.executeQuery(PreparedStatement.java:1923)
          at
          com.mysql.jdbc.DatabaseMetaDataUsingInfoSchema.executeMetadataQuery(
          DatabaseMetaDataUsingInfoSchema.java:50)
          at
          com.mysql.jdbc.DatabaseMetaDataUsingInfoSchema.getExportedKeys(
          DatabaseMetaDataUsingInfoSchema.java:603)

     (Bug #43714)

   * `LoadBalancingConnectionProxy.doPing()' did not have blacklist
     awareness.

     `LoadBalancingConnectionProxy' implemented `doPing()' to ping all
     underlying connections, but it threw any exceptions it encountered
     during this process.

     With the global blacklist enabled, it catches these exceptions,
     adds the host to the global blacklist, and only throws an
     exception if all hosts are down.  (Bug #43421)

   * The method `Statement.getGeneratedKeys()' did not return values
     for `UNSIGNED BIGINTS' with values greater than `Long.MAX_VALUE'.

     Unfortunately, because the server does not tell clients what TYPE
     the auto increment value is, the driver cannot consistently return
     BigIntegers for the result set returned from `getGeneratedKeys()',
     it will only return them if the value is greater than
     `Long.MAX_VALUE'.  If your application needs this consistency, it
     will need to check the class of the return value from
     `.getObject()' on the ResultSet returned by
     `Statement.getGeneratedKeys()' and if it is not a BigInteger,
     create one based on the `java.lang.Long' that is returned.  (Bug
     #43196)

   * When the MySQL Server was upgraded from 4.0 to 5.0, the
     Connector/J application then failed to connect to the server.
     This was because authentication failed when the application ran
     from EBCDIC platforms such as z/OS.  (Bug #43071)

   * When connecting with `traceProtocol=true', no trace data was
     generated for the server greeting or login request.  (Bug #43070)

   * Connector/J generated an unhandled
     `StringIndexOutOfBoundsException':

          java.lang.StringIndexOutOfBoundsException: String index out of range: -1
          at java.lang.String.substring(String.java:1938)
          at com.mysql.jdbc.EscapeProcessor.processTimeToken(EscapeProcessor.java:353)
          at com.mysql.jdbc.EscapeProcessor.escapeSQL(EscapeProcessor.java:257)
          at com.mysql.jdbc.StatementImpl.executeUpdate(StatementImpl.java:1546)
          at com.mysql.jdbc.StatementImpl.executeUpdate(StatementImpl.java:1524)

     (Bug #42253)

   * A `ConcurrentModificationException' was generated in
     `LoadBalancingConnectionProxy':

          java.util.ConcurrentModificationException
           at java.util.HashMap$HashIterator.nextEntry(Unknown Source)
           at java.util.HashMap$KeyIterator.next(Unknown Source)
           at
          com.mysql.jdbc.LoadBalancingConnectionProxy.getGlobalBlacklist(LoadBalancingConnectionProxy.java:520)
           at com.mysql.jdbc.RandomBalanceStrategy.pickConnection(RandomBalanceStrategy.java:55)
           at
          com.mysql.jdbc.LoadBalancingConnectionProxy.pickNewConnection(LoadBalancingConnectionProxy.java:414)
           at
          com.mysql.jdbc.LoadBalancingConnectionProxy.invoke(LoadBalancingConnectionProxy.java:390)

     (Bug #42055)

   * SQL injection was possible when using a string containing U+00A5
     in a client-side prepared statement, and the character set being
     used was SJIS/Windows-31J.  (Bug #41730)

   * If there was an apostrophe in a comment in a statement that was
     being sent through Connector/J, the apostrophe was still
     recognized as a quote and put the state machine in
     `EscapeTokenizer' into the `inQuotes' state. This led to further
     parse errors.

     For example, consider the following statement:

          String sql = "-- Customer's zip code will be fixed\n" +
            "update address set zip_code = 99999\n" +
            "where not regexp '^[0-9]{5}([[.-.]])?([0-9]{4})?$'";

     When passed through Connector/J, the `EscapeTokenizer' did not
     recognize that the first apostrophe was in a comment and thus set
     `inQuotes' to true. When that happened, the quote count was
     incorrect and thus the regular expression did not appear to be in
     quotation marks. With the parser not detecting that the regular
     expression was in quotation marks, the curly braces were
     recognized as escape sequences and were removed from the regular
     expression, breaking it. The server thus received SQL such as:

          -- Customer's zip code will be fixed
          update address set zip_code = '99999'
          where not regexp '^[0-9]([[.-.]])?([0-9])?$'

     (Bug #41566)

   * MySQL Connector/J 5.1.7 was slower than previous versions when the
     `rewriteBatchedStatements' option was set to `true'.

     *Note*:

     The performance regression in
     `indexOfIgnoreCaseRespectMarker()'has been fixed. It has also been
     made possible for the driver to rewrite `INSERT' statements with
     `ON DUPLICATE KEY UPDATE' clauses in them, as long as the `UPDATE'
     clause contains no reference to `LAST_INSERT_ID()', as that would
     cause the driver to return bogus values for `getGeneratedKeys()'
     invocations. This has resulted in improved performance over
     version 5.1.7.

     (Bug #41532)

   * When accessing a result set column by name using
     `ResultSetImpl.findColumn()' an exception was generated:

          java.lang.NullPointerException
          at com.mysql.jdbc.ResultSetImpl.findColumn(ResultSetImpl.java:1103)
          at com.mysql.jdbc.ResultSetImpl.getShort(ResultSetImpl.java:5415)
          at org.apache.commons.dbcp.DelegatingResultSet.getShort(DelegatingResultSet.java:219)
          at com.zimbra.cs.db.DbVolume.constructVolume(DbVolume.java:297)
          at com.zimbra.cs.db.DbVolume.get(DbVolume.java:197)
          at com.zimbra.cs.db.DbVolume.create(DbVolume.java:95)
          at com.zimbra.cs.store.Volume.create(Volume.java:227)
          at com.zimbra.cs.store.Volume.create(Volume.java:189)
          at com.zimbra.cs.service.admin.CreateVolume.handle(CreateVolume.java:48)
          at com.zimbra.soap.SoapEngine.dispatchRequest(SoapEngine.java:428)
          at com.zimbra.soap.SoapEngine.dispatch(SoapEngine.java:285)

     (Bug #41484)

   * The `RETURN_GENERATED_KEYS' flag was being ignored. For example,
     in the following code the `RETURN_GENERATED_KEYS' flag was ignored:

          PreparedStatement ps = connection.prepareStatement("INSERT INTO table
            values(?,?)",PreparedStatement.RETURN_GENERATED_KEYS);

     (Bug #41448)

   * When using Connector/J 5.1.7 to connect to MySQL Server 4.1.18 the
     following error message was generated:

          Thu Dec 11 17:38:21 PST 2008 WARN: Invalid value {1} for server variable named {0},
          falling back to sane default of {2}

     This occurred with MySQL Server version that did not support
     `auto_increment_increment'. The error message should not have been
     generated.  (Bug #41416)

   * When `DatabaseMetaData.getProcedureColumns()' was called, the
     value for `LENGTH' was always returned as 65535, regardless of the
     column type (fixed or variable) or the actual length of the column.

     However, if you obtained the `PRECISION' value, this was correct
     for both fixed and variable length columns.  (Bug #41269)

   * `PreparedStatement.addBatch()' did not check for all parameters
     being set, which led to inconsistent behavior in `executeBatch()',
     especially when rewriting batched statements into multi-value
     `INSERT's.  (Bug #41161)

   * Error message strings contained variable values that were not
     expanded. For example:

          Mon Nov 17 11:43:18 JST 2008 WARN: Invalid value {1} for server variable named {0},
          falling back to sane default of {2}

     (Bug #40772)

   * When using `rewriteBatchedStatements=true' with:

          INSERT INTO table_name_values (...) VALUES (...)

     Query rewriting failed because `values' at the end of the table
     name was mistaken for the reserved keyword. The error generated
     was as follows:

          testBug40439(testsuite.simple.TestBug40439)java.sql.BatchUpdateException: You have an
          error in your SQL syntax; check the manual that corresponds to your MySQL server version
          for the right syntax to use near 'values (2,'toto',2),(id,data, ordr) values
          (3,'toto',3),(id,data, ordr) values (' at line 1
          at com.mysql.jdbc.PreparedStatement.executeBatchedInserts(PreparedStatement.java:1495)
          at com.mysql.jdbc.PreparedStatement.executeBatch(PreparedStatement.java:1097)
          at testsuite.simple.TestBug40439.testBug40439(TestBug40439.java:42)
          at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
          at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39)
          at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
          at testsuite.simple.TestBug40439.main(TestBug40439.java:57)

     (Bug #40439)

   * A statement interceptor received the incorrect parameters when
     used with a batched statement.  (Bug #39426)

   * Using Connector/J 5.1.6 the method `ResultSet.getObject' returned a
     `BYTE[]' for following:

          SELECT TRIM(rowid) FROM tbl

     Where `rowid' had a type of `INT(11) PRIMARY KEY AUTO_INCREMENT'.

     The expected return type was one of `CHAR', `VARCHAR', `CLOB',
     however, a `BYTE[]' was returned.

     Further, adding `functionsNeverReturnBlobs=true' to the connection
     string did not have any effect on the return type.  (Bug #38387)


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D.6.1.12 Changes in MySQL Connector/J 5.1.7 (21 October 2008)
.............................................................

*Functionality Added or Changed*

   * When statements include `ON DUPLICATE UPDATE', and
     `rewriteBatchedStatements' is set to true, batched statements are
     not rewritten into the form `INSERT INTO table VALUES (), (), ()',
     instead the statements are executed sequentially.

*Bugs Fixed*

   * `Statement.getGeneratedKeys()' returned two keys when using `ON
     DUPLICATE KEY UPDATE' and the row was updated, not inserted.  (Bug
     #42309)

   * When using the replication driver with `autoReconnect=true',
     Connector/J checks in `PreparedStatement.execute' (also called by
     `CallableStatement.execute') to determine if the first character
     of the statement is an `S', in an attempt to block all statements
     that are not read-only-safe, for example non-*Note `SELECT':
     select.  statements. However, this also blocked *Note `CALL':
     call.s to stored procedures, even if the stored procedures were
     defined as `SQL READ DATA' or `NO SQL'.  (Bug #40031)

   * With large result sets `ResultSet.findColumn' became a performance
     bottleneck.  (Bug #39962)

   * Connector/J ignored the value of the MySQL Server variable
     `auto_increment_increment'.  (Bug #39956)

   * Connector/J failed to parse *Note `TIMESTAMP': datetime. strings
     for nanos correctly.  (Bug #39911)

   * When the `LoadBalancingConnectionProxy' handles a `SQLException'
     with SQL state starting with `08', it calls
     `invalidateCurrentConnection', which in turn removes that
     `Connection' from `liveConnections' and the
     `connectionsToHostsMap', but it did not add the host to the new
     global blacklist, if the global blacklist was enabled.

     There was also the possibility of a `NullPointerException' when
     trying to update stats, where
     `connectionsToHostsMap.get(this.currentConn)' was called:

          int hostIndex = ((Integer) this.hostsToListIndexMap.get(this.connectionsToHostsMap.get(this.currentConn))).intValue();

     This could happen if a client tried to issue a rollback after
     catching a `SQLException' caused by a connection failure.  (Bug
     #39784)

   * When configuring the Java Replication Driver the last slave
     specified was never used.  (Bug #39611)

   * When an `INSERT ON DUPLICATE KEY UPDATE' was performed, and the
     key already existed, the `affected-rows' value was returned as 1
     instead of 0.  (Bug #39352)

   * When using the random load balancing strategy and starting with
     two servers that were both unavailable, an
     `IndexOutOfBoundsException' was generated when removing a server
     from the `whiteList'.  (Bug #38782)

   * Connector/J threw the following exception when using a read-only
     connection:

          java.sql.SQLException: Connection is read-only. Queries leading to data
          modification are not allowed.

     (Bug #38747)

   * Connector/J was unable to connect when using a non-`latin1'
     password.  (Bug #37570)

   * The `useOldAliasMetadataBehavior' connection property was ignored.
     (Bug #35753)

   * Incorrect result is returned from `isAfterLast()' in streaming
     `ResultSet' when using `setFetchSize(Integer.MIN_VALUE)'.  (Bug
     #35170)

   * When `getGeneratedKeys()' was called on a statement that had not
     been created with `RETURN_GENERATED_KEYS', no exception was
     thrown, and batched executions then returned erroneous values.
     (Bug #34185)

   * The `loadBalance' `bestResponseTime' blacklists did not have a
     global state.  (Bug #33861)


File: manual.info,  Node: cj-news-5-1-6,  Next: cj-news-5-1-5,  Prev: cj-news-5-1-7,  Up: cj-news-5-1-x

D.6.1.13 Changes in MySQL Connector/J 5.1.6 (07 March 2008)
...........................................................

*Functionality Added or Changed*

   * Multiple result sets were not supported when using streaming mode
     to return data. Both normal statements and the resul sets from
     stored procedures now return multiple results sets, with the
     exception of result sets using registered `OUTPUT' parameters.
     (Bug #33678)

   * XAConnections and datasources have been updated to the JDBC-4.0
     standard.

   * The profiler event handling has been made extensible using the
     `profilerEventHandler' connection property.

   * Add the `verifyServerCertificate' property. If set to "false" the
     driver will not verify the server's certificate when `useSSL' is
     set to "true"

     When using this feature, the keystore parameters should be
     specified by the `clientCertificateKeyStore*' properties, rather
     than system properties, as the JSSE doesn't it straightforward to
     have a nonverifying trust store and the "default" key store.

*Bugs Fixed*

   * DatabaseMetaData.getColumns() returns incorrect `COLUMN_SIZE'
     value for `SET' column.  (Bug #36830)

   * When trying to read Time values like `00:00:00' with
     ResultSet.getTime(int) an exception is thrown.  (Bug #36051)

   * JDBC connection URL parameters is ignored when using
     `MysqlConnectionPoolDataSource'.  (Bug #35810)

   * When `useServerPrepStmts=true' and slow query logging is enabled,
     the connector throws a NullPointerException when it encounters a
     slow query.  (Bug #35666)

   * When using the keyword `loadbalance' in the connection string and
     trying to perform load balancing between two databases, the driver
     appears to hang.  (Bug #35660)

   * JDBC data type getter method was changed to accept only column
     name, whereas previously it accepted column label.  (Bug #35610)

   * Prepared statements from pooled connections caused a
     NullPointerException when closed() under JDBC-4.0.  (Bug #35489)

   * In calling a stored function returning a `bigint', an exception is
     encountered beginning:

          java.sql.SQLException: java.lang.NumberFormatException: For input string:

     followed by the text of the stored function starting after the
     argument list.  (Bug #35199)

   * The JDBC driver uses a different method for evaluating column
     names in resultsetmetadata.getColumnName() and when looking for a
     column in resultset.getObject(columnName). This causes Hibernate
     to fail in queries where the two methods yield different results,
     for example in queries that use alias names:

          SELECT column AS aliasName from table

     (Bug #35150)

   * `MysqlConnectionPoolDataSource' does not support
     `ReplicationConnection'. Notice that we implemented
     `com.mysql.jdbc.Connection' for `ReplicationConnection', however,
     only accessors from ConnectionProperties are implemented (not the
     mutators), and they return values from the currently active
     connection. All other methods from `com.mysql.jdbc.Connection' are
     implemented, and operate on the currently active connection, with
     the exception of `resetServerState()' and `changeUser()'.  (Bug
     #34937)

   * `ResultSet.getTimestamp()' returns incorrect values for month/day
     of *Note `TIMESTAMP': datetime.s when using server-side prepared
     statements (not enabled by default).  (Bug #34913)

   * RowDataStatic doesn't always set the metadata in ResultSetRow,
     which can lead to failures when unpacking *Note `DATE': datetime,
     *Note `TIME': time, *Note `DATETIME': datetime. and *Note
     `TIMESTAMP': datetime. types when using absolute, relative, and
     previous result set navigation methods.  (Bug #34762)

   * When calling `isValid()' on an active connection, if the timeout
     is nonzero then the `Connection' is invalidated even if the
     `Connection' is valid.  (Bug #34703)

   * It was not possible to truncate a *Note `BLOB': blob. using
     `Blog.truncate()' when using 0 as an argument.  (Bug #34677)

   * When using a cursor fetch for a statement, the internal prepared
     statement could cause a memory leak until the connection was
     closed. The internal prepared statement is now deleted when the
     corresponding result set is closed.  (Bug #34518)

   * When retrieving the column type name of a geometry field, the
     driver would return `UNKNOWN' instead of `GEOMETRY'.  (Bug #34194)

   * Statements with batched values do not return correct values for
     `getGeneratedKeys()' when `rewriteBatchedStatements' is set to
     `true', and the statement has an `ON DUPLICATE KEY UPDATE' clause.
     (Bug #34093)

   * The internal class ResultSetInternalMethods referenced the
     nonpublic class com.mysql.jdbc.CachedResultSetMetaData.  (Bug
     #33823)

   * A `NullPointerException' could be raised when using client-side
     prepared statements and enabled the prepared statement cache using
     the `cachePrepStmts'.  (Bug #33734)

   * Using server side cursors and cursor fetch, the table metadata
     information would return the data type name instead of the column
     name.  (Bug #33594)

   * ResultSet.getTimestamp() would throw a `NullPointerException'
     instead of a `SQLException' when called on an empty `ResultSet'.
     (Bug #33162)

   * Load balancing connection using best response time would
     incorrectly "stick" to hosts that were down when the connection
     was first created.

     We solve this problem with a black list that is used during the
     picking of new hosts. If the black list ends up including all
     configured hosts, the driver will retry for a configurable number
     of times (the `retriesAllDown' configuration property, with a
     default of 120 times), sleeping 250ms between attempts to pick a
     new connection.

     We've also went ahead and made the balancing strategy extensible.
     To create a new strategy, implement the interface
     com.mysql.jdbc.BalanceStrategy (which also includes our standard
     "extension" interface), and tell the driver to use it by passing
     in the class name using the `loadBalanceStrategy' configuration
     property.  (Bug #32877)

   * During a Daylight Savings Time (DST) switchover, there was no way
     to store two timestamp/datetime values , as the hours end up being
     the same when sent as the literal that MySQL requires.

     Note that to get this scenario to work with MySQL (since it
     doesn't support per-value timezones), you need to configure your
     server (or session) to be in UTC, and tell the driver not to use
     the legacy date/time code by setting `useLegacyDatetimeCode' to
     "false". This will cause the driver to always convert to/from the
     server and client timezone consistently.

     This bug fix also fixes Bug #15604, by adding entirely new
     date/time handling code that can be switched on by
     `useLegacyDatetimeCode' being set to "false" as a JDBC
     configuration property. For Connector/J 5.1.x, the default is
     "true", in trunk and beyond it will be "false" (that is, the old
     date/time handling code will be deprecated) (Bug #32577, Bug
     #15604)

   * When unpacking rows directly, we don't hand off error message
     packets to the internal method which decodes them correctly, so no
     exception is raised, and the driver than hangs trying to read rows
     that aren't there. This tends to happen when calling stored
     procedures, as normal SELECTs won't have an error in this spot in
     the protocol unless an I/O error occurs.  (Bug #32246)

   * When using a connection from ConnectionPoolDataSource, some
     `Connection.prepareStatement()' methods would return null instead
     of the prepared statement.  (Bug #32101)

   * Using `CallableStatement.setNull()' on a stored function would
     throw an `ArrayIndexOutOfBounds' exception when setting the last
     parameter to null.  (Bug #31823)

   * MysqlValidConnectionChecker doesn't properly handle connections
     created using ReplicationConnection.  (Bug #31790)

   * Retrieving the server version information for an active connection
     could return invalid information if the default character encoding
     on the host was not ASCII compatible.  (Bug #31192)

   * Further fixes have been made to this bug in the event that a node
     is nonresponsive. Connector/J will now try a different random node
     instead of waiting for the node to recover before continuing.
     (Bug #31053)

   * `ResultSet' returned by `Statement.getGeneratedKeys()' is not
     closed automatically when statement that created it is closed.
     (Bug #30508)

   * `DatabaseMetadata.getColumns()' doesn't return the correct column
     names if the connection character isn't UTF-8. A bug in MySQL
     server compounded the issue, but was fixed within the MySQL 5.0
     release cycle. The fix includes changes to all the sections of the
     code that access the server metadata.  (Bug #20491)

   * Fixed ResultSetMetadata.getColumnName() for result sets returned
     from Statement.getGeneratedKeys() - it was returning null instead
     of "GENERATED_KEY" as in 5.0.x.


File: manual.info,  Node: cj-news-5-1-5,  Next: cj-news-5-1-4,  Prev: cj-news-5-1-6,  Up: cj-news-5-1-x

D.6.1.14 Changes in MySQL Connector/J 5.1.5 (09 October 2007)
.............................................................

*New     Features, Compared to the 5.0 Series of Connector/J*
   * Support for JDBC-4.0 *Note `NCHAR': char, *Note `NVARCHAR': char.
     and `NCLOB' types.

   * JDBC-4.0 support for setting per-connection client information
     (which can be viewed in the comments section of a query using
     *Note `SHOW PROCESSLIST': show-processlist. on a MySQL server, or
     can be extended to support custom persistence of the information
     using a public interface).

   * Support for JDBC-4.0 XML processing using JAXP interfaces to DOM,
     SAX and StAX.

   * JDBC-4.0 standardized unwrapping to interfaces that include vendor
     extensions.

*Functionality Added or Changed*

   * Added `autoSlowLog' configuration property, overrides
     `slowQueryThreshold*' properties, driver determines slow queries
     by those that are slower than 5 * stddev of the mean query time
     (outside the 96% percentile).

*Bugs Fixed*

   * When a connection is in read-only mode, queries that are wrapped
     in parentheses were incorrectly identified DML statements.  (Bug
     #28256)

   * When calling `setTimestamp' on a prepared statement, the timezone
     information stored in the calendar object was ignored. This
     resulted in the incorrect `DATETIME' information being stored. The
     following example illustrates this:

          Timestamp t = new Timestamp( cal.getTimeInMillis() );
          ps.setTimestamp( N, t, cal );

     (Bug #15604)


File: manual.info,  Node: cj-news-5-1-4,  Next: cj-news-5-1-3,  Prev: cj-news-5-1-5,  Up: cj-news-5-1-x

D.6.1.15 Changes in MySQL Connector/J 5.1.4 (Not Released)
..........................................................

Only released internally.

This section has no changelog entries.


File: manual.info,  Node: cj-news-5-1-3,  Next: cj-news-5-1-2,  Prev: cj-news-5-1-4,  Up: cj-news-5-1-x

D.6.1.16 Changes in MySQL Connector/J 5.1.3 (10 September 2007)
...............................................................

*New     Features, Compared to the 5.0 Series of Connector/J*
   * Support for JDBC-4.0 *Note `NCHAR': char, *Note `NVARCHAR': char.
     and `NCLOB' types.

   * JDBC-4.0 support for setting per-connection client information
     (which can be viewed in the comments section of a query using
     *Note `SHOW PROCESSLIST': show-processlist. on a MySQL server, or
     can be extended to support custom persistence of the information
     using a public interface).

   * Support for JDBC-4.0 XML processing using JAXP interfaces to DOM,
     SAX and StAX.

   * JDBC-4.0 standardized unwrapping to interfaces that include vendor
     extensions.

*Functionality Added or Changed*

   * Connector/J now connects using an initial character set of `utf-8'
     solely for the purpose of authentication to permit user names or
     database names in any character set to be used in the JDBC
     connection URL.  (Bug #29853)

   * Added two configuration parameters:

        * `blobsAreStrings': Should the driver always treat BLOBs as
          Strings. Added specifically to work around dubious metadata
          returned by the server for `GROUP BY' clauses. Defaults to
          false.

        * `functionsNeverReturnBlobs': Should the driver always treat
          data from functions returning `BLOBs' as Strings. Added
          specifically to work around dubious metadata returned by the
          server for `GROUP BY' clauses. Defaults to false.

   * Setting `rewriteBatchedStatements' to `true' now causes
     CallableStatements with batched arguments to be re-written in the
     form "CALL (...); CALL (...); ..." to send the batch in as few
     client/server round trips as possible.

   * The driver now picks appropriate internal row representation
     (whole row in one buffer, or individual byte[]s for each column
     value) depending on heuristics, including whether or not the row
     has *Note `BLOB': blob. or *Note `TEXT': blob. types and the
     overall row-size. The threshold for row size that will cause the
     driver to use a buffer rather than individual byte[]s is
     configured by the configuration property `largeRowSizeThreshold',
     which has a default value of 2KB.

   * The data (and how it is stored) for `ResultSet' rows are now
     behind an interface which enables us (in some cases) to allocate
     less memory per row, in that for "streaming" result sets, we
     re-use the packet used to read rows, since only one row at a time
     is ever active.

   * Added experimental support for statement "interceptors" through
     the `com.mysql.jdbc.StatementInterceptor' interface, examples are
     in `com/mysql/jdbc/interceptors'. Implement this interface to be
     placed "in between" query execution, so that it can be influenced
     (currently experimental).

   * The driver will automatically adjust the server session variable
     `net_write_timeout' when it determines its been asked for a
     "streaming" result, and resets it to the previous value when the
     result set has been consumed.  (The configuration property is named
     `netTimeoutForStreamingResults', with a unit of seconds, the value
     '0' means the driver will not try and adjust this value).

   * JDBC-4.0 ease-of-development features including auto-registration
     with the `DriverManager' through the service provider mechanism,
     standardized Connection validity checks and categorized
     `SQLExceptions' based on recoverability/retry-ability and class of
     the underlying error.

   * `Statement.setQueryTimeout()'s now affect the entire batch for
     batched statements, rather than the individual statements that
     make up the batch.

   * Errors encountered during
     `Statement'/`PreparedStatement'/`CallableStatement.executeBatch()'
     when `rewriteBatchStatements' has been set to `true' now return
     `BatchUpdateExceptions' according to the setting of
     `continueBatchOnError'.

     If `continueBatchOnError' is set to `true', the update counts for
     the "chunk" that were sent as one unit will all be set to
     `EXECUTE_FAILED', but the driver will attempt to process the
     remainder of the batch. You can determine which "chunk" failed by
     looking at the update counts returned in the
     `BatchUpdateException'.

     If `continueBatchOnError' is set to "false", the update counts
     returned will contain all updates up-to and including the failed
     "chunk", with all counts for the failed "chunk" set to
     `EXECUTE_FAILED'.

     Since MySQL doesn't return multiple error codes for
     multiple-statements, or for multi-value *Note `INSERT':
     insert./*Note `REPLACE': replace, it is the application's
     responsibility to handle determining which item(s) in the "chunk"
     actually failed.

   * New methods on com.mysql.jdbc.Statement:
     `setLocalInfileInputStream()' and `getLocalInfileInputStream()':

        * `setLocalInfileInputStream()' sets an `InputStream' instance
          that will be used to send data to the MySQL server for a
          *Note `LOAD DATA LOCAL INFILE': load-data. statement rather
          than a `FileInputStream' or `URLInputStream' that represents
          the path given as an argument to the statement.

          This stream will be read to completion upon execution of a
          *Note `LOAD DATA LOCAL INFILE': load-data. statement, and
          will automatically be closed by the driver, so it needs to be
          reset before each call to `execute*()' that would cause the
          MySQL server to request data to fulfill the request for *Note
          `LOAD DATA LOCAL INFILE': load-data.

          If this value is set to `NULL', the driver will revert to
          using a `FileInputStream' or `URLInputStream' as required.

        * `getLocalInfileInputStream()' returns the `InputStream'
          instance that will be used to send data in response to a
          *Note `LOAD DATA LOCAL INFILE': load-data. statement.

          This method returns `NULL' if no such stream has been set
          using `setLocalInfileInputStream()'.

   * Setting `useBlobToStoreUTF8OutsideBMP' to `true' tells the driver
     to treat `[MEDIUM/LONG]BLOB' columns as `[LONG]VARCHAR' columns
     holding text encoded in UTF-8 that has characters outside the BMP
     (4-byte encodings), which MySQL server can't handle natively.

     Set `utf8OutsideBmpExcludedColumnNamePattern' to a regex so that
     column names matching the given regex will still be treated as
     `BLOBs' The regex must follow the patterns used for the
     `java.util.regex'package.  The default is to exclude no columns,
     and include all columns.

     Set `utf8OutsideBmpIncludedColumnNamePattern' to specify exclusion
     rules to utf8OutsideBmpExcludedColumnNamePattern". The regex must
     follow the patterns used for the `java.util.regex' package.

*Bugs Fixed*

   * `setObject(int, Object, int, int)' delegate in
     PreparedStatementWrapper delegates to wrong method.  (Bug #30892)

   * NPE with null column values when `padCharsWithSpace' is set to
     true.  (Bug #30851)

   * Collation on *Note `VARBINARY': binary-varbinary. column types
     would be misidentified. A fix has been added, but this fix only
     works for MySQL server versions 5.0.25 and newer, since earlier
     versions didn't consistently return correct metadata for
     functions, and thus results from subqueries and functions were
     indistinguishable from each other, leading to type-related bugs.
     (Bug #30664)

   * An `ArithmeticException' or `NullPointerException' would be raised
     when the batch had zero members and
     `rewriteBatchedStatements=true' when `addBatch()' was never
     called, or `executeBatch()' was called immediately after
     `clearBatch()'.  (Bug #30550)

   * Closing a load-balanced connection would cause a
     `ClassCastException'.  (Bug #29852)

   * Connection checker for JBoss didn't use same method parameters
     using reflection, causing connections to always seem "bad".  (Bug
     #29106)

   * `DatabaseMetaData.getTypeInfo()' for the types *Note `DECIMAL':
     numeric-types. and *Note `NUMERIC': numeric-types. will return a
     precision of 254 for server versions older than 5.0.3, 64 for
     versions 5.0.3 to 5.0.5 and 65 for versions newer than 5.0.5.
     (Bug #28972)

   * `CallableStatement.executeBatch()' doesn't work when connection
     property `noAccessToProcedureBodies' has been set to `true'.

     The fix involves changing the behavior of
     `noAccessToProcedureBodies',in that the driver will now report all
     paramters as `IN' paramters but permit callers to call
     registerOutParameter() on them without throwing an exception.
     (Bug #28689)

   * `DatabaseMetaData.getColumns()' doesn't contain `SCOPE_*' or
     `IS_AUTOINCREMENT' columns.  (Bug #27915)

   * Schema objects with identifiers other than the connection
     character aren't retrieved correctly in `ResultSetMetadata'.  (Bug
     #27867)

   * `Connection.getServerCharacterEncoding()' doesn't work for servers
     with version >= 4.1.  (Bug #27182)

   * The automated SVN revisions in `DBMD.getDriverVersion()'. The SVN
     revision of the directory is now inserted into the version
     information during the build.  (Bug #21116)

   * Specifying a "validation query" in your connection pool that
     starts with "/* ping */" _exactly_ will cause the driver to
     instead send a ping to the server and return a fake result set
     (much lighter weight), and when using a ReplicationConnection or a
     LoadBalancedConnection, will send the ping across all active
     connections.


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D.6.1.17 Changes in MySQL Connector/J 5.1.2 (29 June 2007)
..........................................................

This is a new Beta development release, fixing recently discovered bugs.

*Functionality Added or Changed*

   * Setting the configuration property `rewriteBatchedStatements' to
     `true' will now cause the driver to rewrite batched prepared
     statements with more than 3 parameter sets in a batch into
     multi-statements (separated by ";") if they are not plain (that
     is, without *Note `SELECT': select. or `ON DUPLICATE KEY UPDATE'
     clauses) *Note `INSERT': insert. or *Note `REPLACE': replace.
     statements.


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D.6.1.18 Changes in MySQL Connector/J 5.1.1 (22 June 2007)
..........................................................

This is a new Alpha development release, adding new features and fixing
recently discovered bugs.

*Functionality Added or Changed*

   * *Incompatible Change*: Pulled vendor-extension methods of
     `Connection' implementation out into an interface to support
     `java.sql.Wrapper' functionality from `ConnectionPoolDataSource'.
     The vendor extensions are javadoc'd in the
     `com.mysql.jdbc.Connection' interface.

     For those looking further into the driver implementation, it is
     not an API that is used for pluggability of implementations inside
     our driver (which is why there are still references to
     `ConnectionImpl' throughout the code).

     We've also added server and client `prepareStatement()' methods
     that cover all of the variants in the JDBC API.

     `Connection.serverPrepare(String)' has been re-named to
     `Connection.serverPrepareStatement()' for consistency with
     `Connection.clientPrepareStatement()'.

   * Row navigation now causes any streams/readers open on the result
     set to be closed, as in some cases we're reading directly from a
     shared network packet and it will be overwritten by the "next" row.

   * Made it possible to retrieve prepared statement parameter bindings
     (to be used in `StatementInterceptors', primarily).

   * Externalized the descriptions of connection properties.

   * The data (and how it is stored) for `ResultSet' rows are now
     behind an interface which enables us (in some cases) to allocate
     less memory per row, in that for "streaming" result sets, we
     re-use the packet used to read rows, since only one row at a time
     is ever active.

   * Similar to `Connection', we pulled out vendor extensions to
     `Statement' into an interface named `com.mysql.Statement', and
     moved the `Statement' class into `com.mysql.StatementImpl'. The
     two methods (javadoc'd in `com.mysql.Statement' are
     `enableStreamingResults()', which already existed, and
     `disableStreamingResults()' which sets the statement instance back
     to the fetch size and result set type it had before
     `enableStreamingResults()' was called.

   * Driver now picks appropriate internal row representation (whole
     row in one buffer, or individual byte[]s for each column value)
     depending on heuristics, including whether or not the row has
     *Note `BLOB': blob. or *Note `TEXT': blob. types and the overall
     row-size. The threshold for row size that will cause the driver to
     use a buffer rather than individual byte[]s is configured by the
     configuration property `largeRowSizeThreshold', which has a default
     value of 2KB.

   * Added experimental support for statement "interceptors" through
     the `com.mysql.jdbc.StatementInterceptor' interface, examples are
     in `com/mysql/jdbc/interceptors'.

     Implement this interface to be placed "in between" query
     execution, so that you can influence it. (currently experimental).

     `StatementInterceptors' are "chainable" when configured by the
     user, the results returned by the "current" interceptor will be
     passed on to the next on in the chain, from left-to-right order,
     as specified by the user in the JDBC configuration property
     `statementInterceptors'.

   * See the sources (fully javadoc'd) for
     `com.mysql.jdbc.StatementInterceptor' for more details until we
     iron out the API and get it documented in the manual.

   * Setting `rewriteBatchedStatements' to `true' now causes
     `CallableStatements' with batched arguments to be re-written in
     the form `CALL (...); CALL (...); ...' to send the batch in as few
     client/server round trips as possible.


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D.6.1.19 Changes in MySQL Connector/J 5.1.0 (11 April 2007)
...........................................................

This is the first public alpha release of the current Connector/J 5.1
development branch, providing an insight to upcoming features. Although
some of these are still under development, this release includes the
following new features and changes (in comparison to the current
Connector/J 5.0 production release):

*Important change:* Due to a number of issues with the use of
server-side prepared statements, Connector/J 5.0.5 has disabled their
use by default.  The disabling of server-side prepared statements does
not affect the operation of the connector in any way.

To enable server-side prepared statements you must add the following
configuration property to your connector string:

     useServerPrepStmts=true

The default value of this property is `false' (that is, Connector/J
does not use server-side prepared statements).

*Note*:

The disabling of server-side prepared statements does not affect the
operation of the connector. However, if you use the `useTimezone=true'
connection option and use client-side prepared statements (instead of
server-side prepared statements) you should also set
`useSSPSCompatibleTimezoneShift=true'.

*Functionality Added or Changed*

   * Refactored `CommunicationsException' into a JDBC-3.0 version, and
     a JDBC-4.0 version (which extends `SQLRecoverableException', now
     that it exists).

     *Note*:

     This change means that if you were catching
     `com.mysql.jdbc.CommunicationsException' in your applications
     instead of looking at the SQLState class of `08', and are moving
     to Java 6 (or newer), you need to change your imports to that
     exception to be
     `com.mysql.jdbc.exceptions.jdbc4.CommunicationsException', as the
     old class will not be instantiated for communications link-related
     errors under Java 6.

   * Added support for JDBC-4.0 categorized `SQLExceptions'.

   * Added support for JDBC-4.0's `NCLOB', and *Note `NCHAR':
     char./*Note `NVARCHAR': char.  types.

   * `com.mysql.jdbc.java6.javac': Full path to your Java-6 `javac'
     executable

   * Added support for JDBC-4.0's SQLXML interfaces.

   * Re-worked Ant buildfile to build JDBC-4.0 classes separately, as
     well as support building under Eclipse (since Eclipse can't
     mix/match JDKs).

     To build, you must set `JAVA_HOME' to J2SDK-1.4.2 or Java-5, and
     set the following properties on your Ant command line:

        * `com.mysql.jdbc.java6.javac': Full path to your Java-6
          `javac' executable

        * `com.mysql.jdbc.java6.rtjar': Full path to your Java-6
          `rt.jar' file

   * New feature--driver will automatically adjust session variable
     `net_write_timeout' when it determines it has been asked for a
     "streaming" result, and resets it to the previous value when the
     result set has been consumed. (configuration property is named
     `netTimeoutForStreamingResults' value and has a unit of seconds,
     the value `0' means the driver will not try and adjust this value).

   * Added support for JDBC-4.0's client information. The backend
     storage of information provided using `Connection.setClientInfo()'
     and retrieved by `Connection.getClientInfo()' is pluggable by any
     class that implements the `com.mysql.jdbc.JDBC4ClientInfoProvider'
     interface and has a no-args constructor.

     The implementation used by the driver is configured using the
     `clientInfoProvider' configuration property (with a default of
     value of `com.mysql.jdbc.JDBC4CommentClientInfoProvider', an
     implementation which lists the client information as a comment
     prepended to every query sent to the server).

     This functionality is only available when using Java-6 or newer.

   * `com.mysql.jdbc.java6.rtjar': Full path to your Java-6 `rt.jar'
     file

   * Added support for JDBC-4.0's `Wrapper' interface.


File: manual.info,  Node: cj-news-5-0-x,  Next: cj-news-3-1-x,  Prev: cj-news-5-1-x,  Up: cj-news

D.6.2 Changes in MySQL Connector/J 5.0.x
----------------------------------------

* Menu:

* cj-news-5-0-8::                Changes in MySQL Connector/J 5.0.8 (09 October 2007)
* cj-news-5-0-7::                Changes in MySQL Connector/J 5.0.7 (20 July 2007)
* cj-news-5-0-6::                Changes in MySQL Connector/J 5.0.6 (15 May 2007)
* cj-news-5-0-5::                Changes in MySQL Connector/J 5.0.5 (02 March 2007)
* cj-news-5-0-4::                Changes in MySQL Connector/J 5.0.4 (20 October 2006)
* cj-news-5-0-3::                Changes in MySQL Connector/J 5.0.3 (26 July 2006 beta)
* cj-news-5-0-2::                Changes in MySQL Connector/J 5.0.2 (11 July 2006)
* cj-news-5-0-1::                Changes in MySQL Connector/J 5.0.1 (Not Released)
* cj-news-5-0-0::                Changes in MySQL Connector/J 5.0.0 (22 December 2005)


File: manual.info,  Node: cj-news-5-0-8,  Next: cj-news-5-0-7,  Prev: cj-news-5-0-x,  Up: cj-news-5-0-x

D.6.2.1 Changes in MySQL Connector/J 5.0.8 (09 October 2007)
............................................................

*Functionality Added or Changed*

   * `blobsAreStrings': Should the driver always treat BLOBs as
     Strings. Added specifically to work around dubious metadata
     returned by the server for `GROUP BY' clauses. Defaults to false.

   * Added two configuration parameters:

        * `blobsAreStrings': Should the driver always treat BLOBs as
          Strings. Added specifically to work around dubious metadata
          returned by the server for `GROUP BY' clauses. Defaults to
          false.

        * `functionsNeverReturnBlobs': Should the driver always treat
          data from functions returning `BLOBs' as Strings. Added
          specifically to work around dubious metadata returned by the
          server for `GROUP BY' clauses. Defaults to false.

   * `functionsNeverReturnBlobs': Should the driver always treat data
     from functions returning `BLOBs' as Strings. Added specifically to
     work around dubious metadata returned by the server for `GROUP BY'
     clauses. Defaults to false.

   * XAConnections now start in auto-commit mode (as per JDBC-4.0
     specification clarification).

   * Driver will now fall back to sane defaults for
     `max_allowed_packet' and `net_buffer_length' if the server reports
     them incorrectly (and will log this situation at `WARN' level,
     since it is actually an error condition).

*Bugs Fixed*

   * Connections established using URLs of the form
     `jdbc:mysql:loadbalance://' weren't doing failover if they tried
     to connect to a MySQL server that was down. The driver now
     attempts connections to the next "best" (depending on the load
     balance strategy in use) server, and continues to attempt
     connecting to the next "best" server every 250 milliseconds until
     one is found that is up and running or 5 minutes has passed.

     If the driver gives up, it will throw the last-received
     `SQLException'.  (Bug #31053)

   * `setObject(int, Object, int, int)' delegate in
     PreparedStatementWrapper delegates to wrong method.  (Bug #30892)

   * NPE with null column values when `padCharsWithSpace' is set to
     true.  (Bug #30851)

   * Collation on *Note `VARBINARY': binary-varbinary. column types
     would be misidentified. A fix has been added, but this fix only
     works for MySQL server versions 5.0.25 and newer, since earlier
     versions didn't consistently return correct metadata for
     functions, and thus results from subqueries and functions were
     indistinguishable from each other, leading to type-related bugs.
     (Bug #30664)

   * An `ArithmeticException' or `NullPointerException' would be raised
     when the batch had zero members and
     `rewriteBatchedStatements=true' when `addBatch()' was never
     called, or `executeBatch()' was called immediately after
     `clearBatch()'.  (Bug #30550)

   * Closing a load-balanced connection would cause a
     `ClassCastException'.  (Bug #29852)

   * Connection checker for JBoss didn't use same method parameters
     using reflection, causing connections to always seem "bad".  (Bug
     #29106)

   * `DatabaseMetaData.getTypeInfo()' for the types *Note `DECIMAL':
     numeric-types. and *Note `NUMERIC': numeric-types. will return a
     precision of 254 for server versions older than 5.0.3, 64 for
     versions 5.0.3 to 5.0.5 and 65 for versions newer than 5.0.5.
     (Bug #28972)

   * `CallableStatement.executeBatch()' doesn't work when connection
     property `noAccessToProcedureBodies' has been set to `true'.

     The fix involves changing the behavior of
     `noAccessToProcedureBodies',in that the driver will now report all
     paramters as `IN' paramters but permit callers to call
     registerOutParameter() on them without throwing an exception.
     (Bug #28689)

   * When a connection is in read-only mode, queries that are wrapped
     in parentheses were incorrectly identified DML statements.  (Bug
     #28256)

   * `UNSIGNED' types not reported using `DBMD.getTypeInfo()', and
     capitalization of type names is not consistent between
     `DBMD.getColumns()', `RSMD.getColumnTypeName()' and
     `DBMD.getTypeInfo()'.

     This fix also ensures that the precision of `UNSIGNED MEDIUMINT'
     and `UNSIGNED BIGINT' is reported correctly using
     `DBMD.getColumns()'.  (Bug #27916)

   * `DatabaseMetaData.getColumns()' doesn't contain `SCOPE_*' or
     `IS_AUTOINCREMENT' columns.  (Bug #27915)

   * Schema objects with identifiers other than the connection
     character aren't retrieved correctly in `ResultSetMetadata'.  (Bug
     #27867)

   * Cached metadata with `PreparedStatement.execute()' throws
     `NullPointerException'.  (Bug #27412)

   * `Connection.getServerCharacterEncoding()' doesn't work for servers
     with version >= 4.1.  (Bug #27182)

   * The automated SVN revisions in `DBMD.getDriverVersion()'. The SVN
     revision of the directory is now inserted into the version
     information during the build.  (Bug #21116)

   * Specifying a "validation query" in your connection pool that
     starts with "/* ping */" _exactly_ will cause the driver to
     instead send a ping to the server and return a fake result set
     (much lighter weight), and when using a ReplicationConnection or a
     LoadBalancedConnection, will send the ping across all active
     connections.


File: manual.info,  Node: cj-news-5-0-7,  Next: cj-news-5-0-6,  Prev: cj-news-5-0-8,  Up: cj-news-5-0-x

D.6.2.2 Changes in MySQL Connector/J 5.0.7 (20 July 2007)
.........................................................

*Functionality Added or Changed*

   * The driver will now automatically set `useServerPrepStmts' to
     `true' when `useCursorFetch' has been set to `true', since the
     feature requires server-side prepared statements to function.

   * `tcpKeepAlive' - Should the driver set SO_KEEPALIVE (default
     `true')?

   * Give more information in EOFExceptions thrown out of MysqlIO (how
     many bytes the driver expected to read, how many it actually read,
     say that communications with the server were unexpectedly lost).

   * Driver detects when it is running in a ColdFusion MX server
     (tested with version 7), and uses the configuration bundle
     `coldFusion', which sets `useDynamicCharsetInfo' to `false' (see
     previous entry), and sets `useLocalSessionState' and autoReconnect
     to `true'.

   * `tcpNoDelay' - Should the driver set SO_TCP_NODELAY (disabling the
     Nagle Algorithm, default `true')?

   * Added configuration property `slowQueryThresholdNanos' - if
     `useNanosForElapsedTime' is set to `true', and this property is
     set to a nonzero value the driver will use this threshold (in
     nanosecond units) to determine if a query was slow, instead of
     using millisecond units.

   * `tcpRcvBuf' - Should the driver set SO_RCV_BUF to the given value?
     The default value of '0', means use the platform default value for
     this property.

   * Setting `useDynamicCharsetInfo' to `false' now causes driver to
     use static lookups for collations as well (makes
     ResultSetMetadata.isCaseSensitive() much more efficient, which
     leads to performance increase for ColdFusion, which calls this
     method for every column on every table it sees, it appears).

   * Added configuration properties to enable tuning of TCP/IP socket
     parameters:

        * `tcpNoDelay' - Should the driver set SO_TCP_NODELAY
          (disabling the Nagle Algorithm, default `true')?

        * `tcpKeepAlive' - Should the driver set SO_KEEPALIVE (default
          `true')?

        * `tcpRcvBuf' - Should the driver set SO_RCV_BUF to the given
          value? The default value of '0', means use the platform
          default value for this property.

        * `tcpSndBuf' - Should the driver set SO_SND_BUF to the given
          value? The default value of '0', means use the platform
          default value for this property.

        * `tcpTrafficClass' - Should the driver set traffic class or
          type-of-service fields? See the documentation for
          java.net.Socket.setTrafficClass() for more information.

   * Setting the configuration parameter `useCursorFetch' to `true' for
     MySQL-5.0+ enables the use of cursors that enable Connector/J to
     save memory by fetching result set rows in chunks (where the chunk
     size is set by calling setFetchSize() on a Statement or ResultSet)
     by using fully-materialized cursors on the server.

   * `tcpSndBuf' - Should the driver set SO_SND_BUF to the given value?
     The default value of '0', means use the platform default value for
     this property.

   * `tcpTrafficClass' - Should the driver set traffic class or
     type-of-service fields? See the documentation for
     java.net.Socket.setTrafficClass() for more information.

   * Added new debugging functionality - Setting configuration property
     `includeInnodbStatusInDeadlockExceptions' to `true' will cause the
     driver to append the output of *Note `SHOW ENGINE INNODB STATUS':
     show-engine. to deadlock-related exceptions, which will enumerate
     the current locks held inside InnoDB.

   * Added configuration property `useNanosForElapsedTime' - for
     profiling/debugging functionality that measures elapsed time,
     should the driver try to use nanoseconds resolution if available
     (requires JDK >= 1.5)?

     *Note*:

     If `useNanosForElapsedTime' is set to `true', and this property is
     set to "0" (or left default), then elapsed times will still be
     measured in nanoseconds (if possible), but the slow query
     threshold will be converted from milliseconds to nanoseconds, and
     thus have an upper bound of approximately 2000 milliseconds (as
     that threshold is represented as an integer, not a long).

*Bugs Fixed*

   * Don't send any file data in response to LOAD DATA LOCAL INFILE if
     the feature is disabled at the client side. This is to prevent a
     malicious server or man-in-the-middle from asking the client for
     data that the client is not expecting. Thanks to Jan Kneschke for
     discovering the exploit and Andrey "Poohie" Hristov, Konstantin
     Osipov and Sergei Golubchik for discussions about implications and
     possible fixes.  (Bug #29605)

   * Parser in client-side prepared statements runs to end of
     statement, rather than end-of-line for '#' comments. Also added
     support for '-' single-line comments.  (Bug #28956)

   * Parser in client-side prepared statements eats character following
     '/' if it is not a multi-line comment.  (Bug #28851)

   * PreparedStatement.getMetaData() for statements containing leading
     one-line comments is not returned correctly.

     As part of this fix, we also overhauled detection of DML for
     `executeQuery()' and *Note `SELECT': select.s for
     `executeUpdate()' in plain and prepared statements to be aware of
     the same types of comments.  (Bug #28469)


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D.6.2.3 Changes in MySQL Connector/J 5.0.6 (15 May 2007)
........................................................

*Functionality Added or Changed*

   * Added an experimental load-balanced connection designed for use
     with SQL nodes in a MySQL Cluster/NDB environment (This is not for
     master-slave replication. For that, we suggest you look at
     `ReplicationConnection' or `lbpool').

     If the JDBC URL starts with
     `jdbc:mysql:loadbalance://host-1,host-2,...host-n', the driver
     will create an implementation of `java.sql.Connection' that load
     balances requests across a series of MySQL JDBC connections to the
     given hosts, where the balancing takes place after transaction
     commit.

     Therefore, for this to work (at all), you must use transactions,
     even if only reading data.

     Physical connections to the given hosts will not be created until
     needed.

     The driver will invalidate connections that it detects have had
     communication errors when processing a request. A new connection
     to the problematic host will be attempted the next time it is
     selected by the load balancing algorithm.

     There are two choices for load balancing algorithms, which may be
     specified by the `loadBalanceStrategy' JDBC URL configuration
     property:

        * `random': The driver will pick a random host for each
          request. This tends to work better than round-robin, as the
          randomness will somewhat account for spreading loads where
          requests vary in response time, while round-robin can
          sometimes lead to overloaded nodes if there are variations in
          response times across the workload.

        * `bestResponseTime': The driver will route the request to the
          host that had the best response time for the previous
          transaction.

   * `bestResponseTime': The driver will route the request to the host
     that had the best response time for the previous transaction.

   * Added configuration property `padCharsWithSpace' (defaults to
     `false'). If set to `true', and a result set column has the *Note
     `CHAR': char. type and the value does not fill the amount of
     characters specified in the DDL for the column, the driver will
     pad the remaining characters with space (for ANSI compliance).

   * When `useLocalSessionState' is set to `true' and connected to a
     MySQL-5.0 or later server, the JDBC driver will now determine
     whether an actual `commit' or `rollback' statement needs to be
     sent to the database when `Connection.commit()' or
     `Connection.rollback()' is called.

     This is especially helpful for high-load situations with
     connection pools that always call `Connection.rollback()' on
     connection check-in/check-out because it avoids a round-trip to
     the server.

   * Added configuration property `useDynamicCharsetInfo'. If set to
     `false' (the default), the driver will use a per-connection cache
     of character set information queried from the server when
     necessary, or when set to `true', use a built-in static mapping
     that is more efficient, but isn't aware of custom character sets or
     character sets implemented after the release of the JDBC driver.

     *Note*:

     This only affects the `padCharsWithSpace' configuration property
     and the `ResultSetMetaData.getColumnDisplayWidth()' method.

   * New configuration property, `enableQueryTimeouts' (default `true').

     When enabled, query timeouts set with
     `Statement.setQueryTimeout()' use a shared `java.util.Timer'
     instance for scheduling. Even if the timeout doesn't expire before
     the query is processed, there will be memory used by the
     `TimerTask' for the given timeout which won't be reclaimed until
     the time the timeout would have expired if it hadn't been
     cancelled by the driver. High-load environments might want to
     consider disabling this functionality. (this configuration
     property is part of the `maxPerformance' configuration bundle).

   * Give better error message when "streaming" result sets, and the
     connection gets clobbered because of exceeding `net_write_timeout'
     on the server.

   * `random': The driver will pick a random host for each request.
     This tends to work better than round-robin, as the randomness will
     somewhat account for spreading loads where requests vary in
     response time, while round-robin can sometimes lead to overloaded
     nodes if there are variations in response times across the
     workload.

   * `com.mysql.jdbc.[NonRegistering]Driver' now understands URLs of
     the format `jdbc:mysql:replication://' and
     `jdbc:mysql:loadbalance://' which will create a
     ReplicationConnection (exactly like when using
     `[NonRegistering]ReplicationDriver') and an experimental
     load-balanced connection designed for use with SQL nodes in a
     MySQL Cluster/NDB environment, respectively.

     In an effort to simplify things, we're working on deprecating
     multiple drivers, and instead specifying different core behavior
     based upon JDBC URL prefixes, so watch for
     `[NonRegistering]ReplicationDriver' to eventually disappear, to be
     replaced with `com.mysql.jdbc[NonRegistering]Driver' with the new
     URL prefix.

   * Fixed issue where a failed-over connection would let an
     application call `setReadOnly(false)', when that call should be
     ignored until the connection is reconnected to a writable master
     unless `failoverReadOnly' had been set to `false'.

   * Driver will now use `INSERT INTO ... VALUES (DEFAULT)'form of
     statement for updatable result sets for `ResultSet.insertRow()',
     rather than pre-populating the insert row with values from
     `DatabaseMetaData.getColumns()'(which results in a *Note `SHOW
     FULL COLUMNS': show-columns. on the server for every result set).
     If an application requires access to the default values before
     `insertRow()' has been called, the JDBC URL should be configured
     with `populateInsertRowWithDefaultValues' set to `true'.

     This fix specifically targets performance issues with ColdFusion
     and the fact that it seems to ask for updatable result sets no
     matter what the application does with them.

   * More intelligent initial packet sizes for the "shared" packets are
     used (512 bytes, rather than 16K), and initial packets used during
     handshake are now sized appropriately as to not require
     reallocation.

*Bugs Fixed*

   * More useful error messages are generated when the driver thinks a
     result set is not updatable. (Thanks to Ashley Martens for the
     patch).  (Bug #28085)

   * `Connection.getTransactionIsolation()' uses "`SHOW VARIABLES
     LIKE'" which is very inefficient on MySQL-5.0+ servers.  (Bug
     #27655)

   * Fixed issue where calling `getGeneratedKeys()' on a prepared
     statement after calling `execute()' didn't always return the
     generated keys (`executeUpdate()' worked fine however).  (Bug
     #27655)

   * `CALL /* ... */ SOME_PROC()' doesn't work.  As a side effect of
     this fix, you can now use `/* */' and `#' comments when preparing
     statements using client-side prepared statement emulation.

     If the comments happen to contain parameter markers (`?'), they
     will be treated as belonging to the comment (that is, not
     recognized) rather than being a parameter of the statement.

     *Note*:

     The statement when sent to the server will contain the comments
     as-is, they're not stripped during the process of preparing the
     `PreparedStatement' or `CallableStatement'.

     (Bug #27400)

   * `ResultSet.get*()' with a column index < 1 returns misleading
     error message.  (Bug #27317)

   * Using `ResultSet.get*()' with a column index less than 1 returns a
     misleading error message.  (Bug #27317)

   * Comments in DDL of stored procedures/functions confuse procedure
     parser, and thus metadata about them can not be created, leading
     to inability to retrieve said metadata, or execute procedures that
     have certain comments in them.  (Bug #26959)

   * Fast date/time parsing doesn't take into account `00:00:00' as a
     legal value.  (Bug #26789)

   * `PreparedStatement' is not closed in `BlobFromLocator.getBytes()'.
     (Bug #26592)

   * When the configuration property `useCursorFetch' was set to
     `true', sometimes server would return new, more exact metadata
     during the execution of the server-side prepared statement that
     enables this functionality, which the driver ignored (using the
     original metadata returned during `prepare()'), causing corrupt
     reading of data due to type mismatch when the actual rows were
     returned.  (Bug #26173)

   * `CallableStatements' with `OUT/INOUT' parameters that are "binary"
     (*Note `BLOB': blob, *Note `BIT': numeric-types, `(VAR)BINARY',
     `JAVA_OBJECT') have extra 7 bytes.  (Bug #25715)

   * Whitespace surrounding storage/size specifiers in stored procedure
     parameters declaration causes `NumberFormatException' to be thrown
     when calling stored procedure on JDK-1.5 or newer, as the Number
     classes in JDK-1.5+ are whitespace intolerant.  (Bug #25624)

   * Client options not sent correctly when using SSL, leading to
     stored procedures not being able to return results. Thanks to Don
     Cohen for the bug report, testcase and patch.  (Bug #25545)

   * `Statement.setMaxRows()' is not effective on result sets
     materialized from cursors.  (Bug #25517)

   * `BIT(> 1)' is returned as `java.lang.String' from
     `ResultSet.getObject()' rather than `byte[]'.  (Bug #25328)


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D.6.2.4 Changes in MySQL Connector/J 5.0.5 (02 March 2007)
..........................................................

*Functionality Added or Changed*

   * Usage Advisor will now issue warnings for result sets with large
     numbers of rows. You can configure the trigger value by using the
     `resultSetSizeThreshold' parameter, which has a default value of
     100.

   * The `rewriteBatchedStatements' feature can now be used with
     server-side prepared statements.

   * *Important change:* Due to a number of issues with the use of
     server-side prepared statements, Connector/J 5.0.5 has disabled
     their use by default.  The disabling of server-side prepared
     statements does not affect the operation of the connector in any
     way.

     To enable server-side prepared statements you must add the
     following configuration property to your connector string:

          useServerPrepStmts=true

     The default value of this property is `false' (that is,
     Connector/J does not use server-side prepared statements).

   * Improved speed of `datetime' parsing for ResultSets that come from
     plain or nonserver-side prepared statements. You can enable old
     implementation with `useFastDateParsing=false' as a configuration
     parameter.

   * Usage Advisor now detects empty results sets and does not report
     on columns not referenced in those empty sets.

   * Fixed logging of XA commands sent to server, it is now
     configurable using `logXaCommands' property (defaults to `false').

   * Added configuration property `localSocketAddress', which is the
     host name or IP address given to explicitly configure the
     interface that the driver will bind the client side of the TCP/IP
     connection to when connecting.

   * We've added a new configuration option `treatUtilDateAsTimestamp',
     which is `false' by default, as (1) We already had specific
     behavior to treat java.util.Date as a java.sql.Timestamp because
     it is useful to many folks, and (2) that behavior will very likely
     be required for drivers JDBC-post-4.0.

*Bugs Fixed*

   * Connection property `socketFactory' wasn't exposed using correctly
     named mutator/accessor, causing data source implementations that
     use JavaBean naming conventions to set properties to fail to set
     the property (and in the case of SJAS, fail silently when trying
     to set this parameter).  (Bug #26326)

   * A query execution which timed out did not always throw a
     `MySQLTimeoutException'.  (Bug #25836)

   * Storing a `java.util.Date' object in a *Note `BLOB': blob. column
     would not be serialized correctly during `setObject'.  (Bug #25787)

   * Timer instance used for `Statement.setQueryTimeout()' created
     per-connection, rather than per-VM, causing memory leak.  (Bug
     #25514)

   * `EscapeProcessor' gets confused by multiple backslashes. We now
     push the responsibility of syntax errors back on to the server for
     most escape sequences.  (Bug #25399)

   * `INOUT' parameters in `CallableStatements' get doubly-escaped.
     (Bug #25379)

   * When using the `rewriteBatchedStatements' connection option with
     `PreparedState.executeBatch()' an internal memory leak would occur.
     (Bug #25073)

   * Fixed issue where field-level for metadata from `DatabaseMetaData'
     when using `INFORMATION_SCHEMA' didn't have references to current
     connections, sometimes leading to Null Pointer Exceptions (NPEs)
     when introspecting them using `ResultSetMetaData'.  (Bug #25073)

   * `StringUtils.indexOfIgnoreCaseRespectQuotes()' isn't
     case-insensitive on the first character of the target.  This bug
     also affected `rewriteBatchedStatements' functionality when
     prepared statements did not use uppercase for the `VALUES' clause.
     (Bug #25047)

   * Client-side prepared statement parser gets confused by in-line
     comments `/*...*/' and therefore cannot rewrite batch statements
     or reliably detect the type of statements when they are used.
     (Bug #25025)

   * Results sets from *Note `UPDATE': update.  statements that are
     part of multi-statement queries would cause an `SQLException'
     error, "Result is from UPDATE".  (Bug #25009)

   * Specifying `US-ASCII' as the character set in a connection to a
     MySQL 4.1 or newer server does not map correctly.  (Bug #24840)

   * Using `DatabaseMetaData.getSQLKeywords()' does not return a all of
     the of the reserved keywords for the current MySQL version.
     Current implementation returns the list of reserved words for
     MySQL 5.1, and does not distinguish between versions.  (Bug #24794)

   * Calling `Statement.cancel()' could result in a Null Pointer
     Exception (NPE).  (Bug #24721)

   * Using `setFetchSize()' breaks prepared *Note `SHOW': show. and
     other commands.  (Bug #24360)

   * Calendars and timezones are now lazily instantiated when required.
     (Bug #24351)

   * Using *Note `DATETIME': datetime. columns would result in time
     shifts when `useServerPrepStmts' was true. This occurred due to
     different behavior when using client-side compared to server-side
     prepared statements and the `useJDBCCompliantTimezoneShift'
     option. This is now fixed if moving from server-side prepared
     statements to client-side prepared statements by setting
     `useSSPSCompatibleTimezoneShift' to `true', as the driver can't
     tell if this is a new deployment that never used server-side
     prepared statements, or if it is an existing deployment that is
     switching to client-side prepared statements from server-side
     prepared statements.  (Bug #24344)

   * Connector/J now returns a better error message when server doesn't
     return enough information to determine stored procedure/function
     parameter types.  (Bug #24065)

   * A connection error would occur when connecting to a MySQL server
     with certain character sets. Some collations/character sets
     reported as "unknown" (specifically `cias' variants of existing
     character sets), and inability to override the detected server
     character set.  (Bug #23645)

   * Inconsistency between `getSchemas' and `INFORMATION_SCHEMA'.  (Bug
     #23304)

   * `DatabaseMetaData.getSchemas()' doesn't return a `TABLE_CATALOG'
     column.  (Bug #23303)

   * When using a JDBC connection URL that is malformed, the
     `NonRegisteringDriver.getPropertyInfo' method will throw a Null
     Pointer Exception (NPE).  (Bug #22628)

   * Some exceptions thrown out of `StandardSocketFactory' were
     needlessly wrapped, obscuring their true cause, especially when
     using socket timeouts.  (Bug #21480)

   * When using a server-side prepared statement the driver would send
     timestamps to the server using nanoseconds instead of milliseconds.
     (Bug #21438)

   * When using server-side prepared statements and timestamp columns,
     value would be incorrectly populated (with nanoseconds, not
     microseconds).  (Bug #21438)

   * `ParameterMetaData' throws `NullPointerException' when prepared
     SQL has a syntax error. Added `generateSimpleParameterMetadata'
     configuration property, which when set to `true' will generate
     metadata reflecting *Note `VARCHAR': char. for every parameter (the
     default is `false', which will cause an exception to be thrown if
     no parameter metadata for the statement is actually available).
     (Bug #21267)

   * Fixed an issue where `XADataSources' couldn't be bound into JNDI,
     as the `DataSourceFactory' didn't know how to create instances of
     them.

*Other Changes*

   * Avoid static synchronized code in JVM class libraries for dealing
     with default timezones.

   * Performance enhancement of initial character set configuration,
     driver will only send commands required to configure connection
     character set session variables if the current values on the
     server do not match what is required.

   * Re-worked stored procedure parameter parser to be more robust.
     Driver no longer requires `BEGIN' in stored procedure definition,
     but does have requirement that if a stored function begins with a
     label directly after the "returns" clause, that the label is not a
     quoted identifier.

   * Throw exceptions encountered during timeout to thread calling
     `Statement.execute*()', rather than `RuntimeException'.

   * Changed cached result set metadata (when using
     `cacheResultSetMetadata=true') to be cached per-connection rather
     than per-statement as previously implemented.

   * Reverted back to internal character conversion routines for
     single-byte character sets, as the ones internal to the JVM are
     using much more CPU time than our internal implementation.

   * When extracting foreign key information from *Note `SHOW CREATE
     TABLE': show-create-table. in `DatabaseMetaData', ignore
     exceptions relating to tables being missing (which could happen
     for cross-reference or imported-key requests, as the list of
     tables is generated first, then iterated).

   * Fixed some Null Pointer Exceptions (NPEs) when cached metadata was
     used with `UpdatableResultSets'.

   * Take `localSocketAddress' property into account when creating
     instances of `CommunicationsException' when the underlying
     exception is a `java.net.BindException', so that a friendlier
     error message is given with a little internal diagnostics.

   * Fixed cases where `ServerPreparedStatements' weren't using cached
     metadata when `cacheResultSetMetadata=true' was used.

   * Use a `java.util.TreeMap' to map column names to ordinal indexes
     for `ResultSet.findColumn()' instead of a HashMap. This enables us
     to have case-insensitive lookups (required by the JDBC
     specification) without resorting to the many transient object
     instances needed to support this requirement with a normal
     `HashMap' with either case-adjusted keys, or case-insensitive
     keys. (In the worst case scenario for lookups of a 1000 column
     result set, TreeMaps are about half as fast wall-clock time as a
     HashMap, however in normal applications their use gives many
     orders of magnitude reduction in transient object instance
     creation which pays off later for CPU usage in garbage collection).

   * When using cached metadata, skip field-level metadata packets
     coming from the server, rather than reading them and discarding
     them without creating `com.mysql.jdbc.Field' instances.


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D.6.2.5 Changes in MySQL Connector/J 5.0.4 (20 October 2006)
............................................................

*Bugs Fixed*

   * DBMD.getColumns() does not return expected COLUMN_SIZE for the SET
     type, now returns length of largest possible set disregarding
     whitespace or the "," delimitters to be consistent with the ODBC
     driver.  (Bug #22613)

   * Added new _ci collations to CharsetMapping - utf8_unicode_ci not
     working.  (Bug #22456)

   * Driver was using milliseconds for Statement.setQueryTimeout() when
     specification says argument is to be in seconds.  (Bug #22359)

   * Workaround for server crash when calling stored procedures using a
     server-side prepared statement (driver now detects prepare(stored
     procedure) and substitutes client-side prepared statement).  (Bug
     #22297)

   * Driver issues truncation on write exception when it shouldn't (due
     to sending big decimal incorrectly to server with server-side
     prepared statement).  (Bug #22290)

   * Newlines causing whitespace to span confuse procedure parser when
     getting parameter metadata for stored procedures.  (Bug #22024)

   * When using information_schema for metadata, COLUMN_SIZE for
     getColumns() is not clamped to range of java.lang.Integer as is
     the case when not using information_schema, thus leading to a
     truncation exception that isn't present when not using
     information_schema.  (Bug #21544)

   * Column names don't match metadata in cases where server doesn't
     return original column names (column functions) thus breaking
     compatibility with applications that expect 1-to-1 mappings
     between `findColumn()' and `rsmd.getColumnName()', usually
     manifests itself as "Can't find column (")" exceptions.  (Bug
     #21379)

   * Driver now sends numeric 1 or 0 for client-prepared statement
     `setBoolean()' calls instead of '1' or '0'.

   * Fixed configuration property `jdbcCompliantTruncation' was not
     being used for reads of result set values.

   * DatabaseMetaData correctly reports `true' for `supportsCatalog*()'
     methods.

   * Driver now supports `{call sp}' (without "()" if procedure has no
     arguments).


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D.6.2.6 Changes in MySQL Connector/J 5.0.3 (26 July 2006 beta)
..............................................................

*Functionality Added or Changed*

   * Added configuration option `noAccessToProcedureBodies' which will
     cause the driver to create basic parameter metadata for
     `CallableStatements' when the user does not have access to
     procedure bodies using *Note `SHOW CREATE PROCEDURE':
     show-create-procedure. or selecting from `mysql.proc' instead of
     throwing an exception.  The default value for this option is
     `false'

*Bugs Fixed*

   * Fixed `Statement.cancel()' causes `NullPointerException' if
     underlying connection has been closed due to server failure.  (Bug
     #20650)

   * If the connection to the server has been closed due to a server
     failure, then the cleanup process will call ` Statement.cancel()',
     triggering a `NullPointerException', even though there is no
     active connection.  (Bug #20650)


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D.6.2.7 Changes in MySQL Connector/J 5.0.2 (11 July 2006)
.........................................................

*Bugs Fixed*

   * `MysqlXaConnection.recover(int flags)' now permits combinations of
     `XAResource.TMSTARTRSCAN' and `TMENDRSCAN'. To simulate the
     `scanning' nature of the interface, we return all prepared XIDs
     for `TMSTARTRSCAN', and no new XIDs for calls with `TMNOFLAGS', or
     `TMENDRSCAN' when not in combination with `TMSTARTRSCAN'. This
     change was made for API compliance, as well as integration with
     IBM WebSphere's transaction manager.  (Bug #20242)

   * Fixed `MysqlValidConnectionChecker' for JBoss doesn't work with
     `MySQLXADataSources'.  (Bug #20242)

   * Added connection/datasource property
     `pinGlobalTxToPhysicalConnection' (defaults to `false'). When set
     to `true', when using `XAConnections', the driver ensures that
     operations on a given XID are always routed to the same physical
     connection. This enables the `XAConnection' to support `XA START
     ...  JOIN' after *Note `XA END': xa-statements.  has been called,
     and is also a workaround for transaction managers that don't
     maintain thread affinity for a global transaction (most either
     always maintain thread affinity, or have it as a configuration
     option).  (Bug #20242)

   * Better caching of character set converters (per-connection) to
     remove a bottleneck for multibyte character sets.  (Bug #20242)

   * Fixed `ConnectionProperties' (and thus some subclasses) are not
     serializable, even though some J2EE containers expect them to be.
     (Bug #19169)

   * Fixed driver fails on non-ASCII platforms. The driver was assuming
     that the platform character set would be a superset of MySQL's
     `latin1' when doing the handshake for authentication, and when
     reading error messages. We now use Cp1252 for all strings sent to
     the server during the handshake phase, and a hard-coded mapping of
     the `language' system variable to the character set that is used
     for error messages.  (Bug #18086)

   * Fixed can't use `XAConnection' for local transactions when no
     global transaction is in progress.  (Bug #17401)


File: manual.info,  Node: cj-news-5-0-1,  Next: cj-news-5-0-0,  Prev: cj-news-5-0-2,  Up: cj-news-5-0-x

D.6.2.8 Changes in MySQL Connector/J 5.0.1 (Not Released)
.........................................................

Not released due to a packaging error

This section has no changelog entries.


File: manual.info,  Node: cj-news-5-0-0,  Prev: cj-news-5-0-1,  Up: cj-news-5-0-x

D.6.2.9 Changes in MySQL Connector/J 5.0.0 (22 December 2005)
.............................................................

*Bugs Fixed*

   * Added support for Connector/MXJ integration using url subprotocol
     `jdbc:mysql:mxj://...'.  (Bug #14729)

   * Idle timeouts cause `XAConnections' to whine about rolling
     themselves back.  (Bug #14729)

   * When fix for Bug #14562 was merged from 3.1.12, added
     functionality for `CallableStatement''s parameter metadata to
     return correct information for `.getParameterClassName()'.  (Bug
     #14729)

   * Added service-provider entry to
     `META-INF/services/java.sql.Driver' for JDBC-4.0 support.  (Bug
     #14729)

   * Fuller synchronization of `Connection' to avoid deadlocks when
     using multithreaded frameworks that multithread a single
     connection (usually not recommended, but the JDBC spec permits it
     anyways), part of fix to Bug #14972).  (Bug #14729)

   * Moved all `SQLException' constructor usage to a factory in
     `SQLError' (ground-work for JDBC-4.0 `SQLState'-based exception
     classes).  (Bug #14729)

   * Removed Java5-specific calls to `BigDecimal' constructor (when
     result set value is `''', `(int)0' was being used as an argument
     indirectly using method return value. This signature doesn't exist
     prior to Java5.)  (Bug #14729)

   * Implementation of `Statement.cancel()' and
     `Statement.setQueryTimeout()'. Both require MySQL-5.0.0 or newer
     server, require a separate connection to issue the *Note `KILL
     QUERY': kill. statement, and in the case of `setQueryTimeout()'
     creates an additional thread to handle the timeout functionality.

     Note: Failures to cancel the statement for `setQueryTimeout()' may
     manifest themselves as `RuntimeExceptions' rather than failing
     silently, as there is currently no way to unblock the thread that
     is executing the query being cancelled due to timeout expiration
     and have it throw the exception instead.  (Bug #14729)

   * Return "[VAR]BINARY" for `RSMD.getColumnTypeName()' when that is
     actually the type, and it can be distinguished (MySQL-4.1 and
     newer).  (Bug #14729)

   * Attempt detection of the MySQL type *Note `BINARY':
     binary-varbinary. (it is an alias, so this isn't always reliable),
     and use the `java.sql.Types.BINARY' type mapping for it.

   * Added unit tests for `XADatasource', as well as friendlier
     exceptions for XA failures compared to the "stock" `XAException'
     (which has no messages).

   * If the connection `useTimezone' is set to `true', then also
     respect time zone conversions in escape-processed string literals
     (for example, `"{ts ...}"' and `"{t ...}"').

   * Do not permit `.setAutoCommit(true)', or `.commit()' or
     `.rollback()' on an XA-managed connection as per the JDBC
     specification.

   * `XADataSource' implemented (ported from 3.2 branch which won't be
     released as a product). Use
     `com.mysql.jdbc.jdbc2.optional.MysqlXADataSource' as your
     datasource class name in your application server to utilize XA
     transactions in MySQL-5.0.10 and newer.

   * Moved `-bin-g.jar' file into separate `debug' subdirectory to
     avoid confusion.

   * Return original column name for `RSMD.getColumnName()' if the
     column was aliased, alias name for `.getColumnLabel()' (if
     aliased), and original table name for `.getTableName()'. Note this
     only works for MySQL-4.1 and newer, as older servers don't make
     this information available to clients.

   * Setting `useJDBCCompliantTimezoneShift=true' (it is not the
     default) causes the driver to use GMT for _all_ *Note `TIMESTAMP':
     datetime./*Note `DATETIME': datetime.  time zones, and the current
     VM time zone for any other type that refers to time zones. This
     feature can not be used when `useTimezone=true' to convert between
     server and client time zones.

   * `PreparedStatement.setString()' didn't work correctly when
     `sql_mode' on server contained `NO_BACKSLASH_ESCAPES' and no
     characters that needed escaping were present in the string.

   * Add one level of indirection of internal representation of
     `CallableStatement' parameter metadata to avoid class not found
     issues on JDK-1.3 for `ParameterMetadata' interface (which doesn't
     exist prior to JDBC-3.0).


File: manual.info,  Node: cj-news-3-1-x,  Next: cj-news-3-0-x,  Prev: cj-news-5-0-x,  Up: cj-news

D.6.3 Changes in MySQL Connector/J 3.1.x
----------------------------------------

* Menu:

* cj-news-3-1-15::               Changes in MySQL Connector/J 3.1.15 (Not yet released)
* cj-news-3-1-14::               Changes in MySQL Connector/J 3.1.14 (19 October 2006)
* cj-news-3-1-13::               Changes in MySQL Connector/J 3.1.13 (26 May 2006)
* cj-news-3-1-12::               Changes in MySQL Connector/J 3.1.12 (30 November 2005)
* cj-news-3-1-11::               Changes in MySQL Connector/J 3.1.11 (07 October 2005)
* cj-news-3-1-10::               Changes in MySQL Connector/J 3.1.10 (23 June 2005)
* cj-news-3-1-9::                Changes in MySQL Connector/J 3.1.9 (22 June 2005)
* cj-news-3-1-8::                Changes in MySQL Connector/J 3.1.8 (14 April 2005)
* cj-news-3-1-7::                Changes in MySQL Connector/J 3.1.7 (18 February 2005)
* cj-news-3-1-6::                Changes in MySQL Connector/J 3.1.6 (23 December 2004)
* cj-news-3-1-5::                Changes in MySQL Connector/J 3.1.5 (02 December 2004)
* cj-news-3-1-4::                Changes in MySQL Connector/J 3.1.4 (04 September 2004)
* cj-news-3-1-3::                Changes in MySQL Connector/J 3.1.3 (07 July 2004)
* cj-news-3-1-2::                Changes in MySQL Connector/J 3.1.2 (09 June 2004)
* cj-news-3-1-1::                Changes in MySQL Connector/J 3.1.1 (14 February 2004 alpha)
* cj-news-3-1-0::                Changes in MySQL Connector/J 3.1.0 (18 February 2003 alpha)


File: manual.info,  Node: cj-news-3-1-15,  Next: cj-news-3-1-14,  Prev: cj-news-3-1-x,  Up: cj-news-3-1-x

D.6.3.1 Changes in MySQL Connector/J 3.1.15 (Not yet released)
..............................................................

*Important change:* Due to a number of issues with the use of
server-side prepared statements, Connector/J 5.0.5 has disabled their
use by default.  The disabling of server-side prepared statements does
not affect the operation of the connector in any way.

To enable server-side prepared statements you must add the following
configuration property to your connector string:

     useServerPrepStmts=true

The default value of this property is `false' (that is, Connector/J
does not use server-side prepared statements).

*Bugs Fixed*

   * Specifying `US-ASCII' as the character set in a connection to a
     MySQL 4.1 or newer server does not map correctly.  (Bug #24840)


File: manual.info,  Node: cj-news-3-1-14,  Next: cj-news-3-1-13,  Prev: cj-news-3-1-15,  Up: cj-news-3-1-x

D.6.3.2 Changes in MySQL Connector/J 3.1.14 (19 October 2006)
.............................................................

*Bugs Fixed*

   * Check and store value for continueBatchOnError property in
     constructor of Statements, rather than when executing batches, so
     that Connections closed out from underneath statements don't cause
     NullPointerExceptions when it is required to check this property.
     (Bug #22290)

   * Driver now sends numeric 1 or 0 for client-prepared statement
     setBoolean() calls instead of '1' or '0'.  (Bug #22290)

   * Fixed bug where driver would not advance to next host if
     roundRobinLoadBalance=true and the last host in the list is down.
     (Bug #22290)

   * Driver issues truncation on write exception when it shouldn't (due
     to sending big decimal incorrectly to server with server-side
     prepared statement).  (Bug #22290)

   * Fixed bug when calling stored functions, where parameters weren't
     numbered correctly (first parameter is now the return value,
     subsequent parameters if specified start at index "2").  (Bug
     #22290)

   * Removed logger autodetection altogether, must now specify logger
     explicitly if you want to use a logger other than one that logs to
     STDERR.  (Bug #21207)

   * DDriver throws NPE when tracing prepared statements that have been
     closed (in asSQL()).  (Bug #21207)

   * ResultSet.getSomeInteger() doesn't work for BIT(>1).  (Bug #21062)

   * Escape of quotation marks in client-side prepared statements
     parsing not respected. Patch covers more than bug report,
     including NO_BACKSLASH_ESCAPES being set, and stacked quote
     characters forms of escaping (that is, " or "").  (Bug #20888)

   * Fixed can't pool server-side prepared statements, exception raised
     when re-using them.  (Bug #20687)

   * Fixed Updatable result set that contains a BIT column fails when
     server-side prepared statements are used.  (Bug #20485)

   * Fixed updatable result set throws ClassCastException when there is
     row data and moveToInsertRow() is called.  (Bug #20479)

   * Fixed ResultSet.getShort() for UNSIGNED TINYINT returns incorrect
     values when using server-side prepared statements.  (Bug #20306)

   * ReplicationDriver does not always round-robin load balance
     depending on URL used for slaves list.  (Bug #19993)

   * Fixed calling toString() on ResultSetMetaData for driver-generated
     (that is, from DatabaseMetaData method calls, or from
     getGeneratedKeys()) result sets would raise a NullPointerException.
     (Bug #19993)

   * Connection fails to localhost when using timeout and IPv6 is
     configured.  (Bug #19726)

   * ResultSet.getFloatFromString() can't retrieve values near
     Float.MIN/MAX_VALUE.  (Bug #18880)

   * `DatabaseMetaData.getTables()' or `getColumns()' with a bad
     catalog parameter threw an exception rather than return an empty
     result set (as required by the specification).  (Bug #18258)

   * Fixed memory leak with profileSQL=true.  (Bug #16987)

   * Fixed NullPointerException in MysqlDataSourceFactory due to
     Reference containing RefAddrs with null content.  (Bug #16791)


File: manual.info,  Node: cj-news-3-1-13,  Next: cj-news-3-1-12,  Prev: cj-news-3-1-14,  Up: cj-news-3-1-x

D.6.3.3 Changes in MySQL Connector/J 3.1.13 (26 May 2006)
.........................................................

*Bugs Fixed*

   * `Fixed PreparedStatement.setObject(int, Object, int)' doesn't
     respect scale of BigDecimals.  (Bug #19615)

   * Fixed `ResultSet.wasNull()' returns incorrect value when
     extracting native string from server-side prepared statement
     generated result set.  (Bug #19282)

   * Fixed invalid classname returned for
     `ResultSetMetaData.getColumnClassName()' for `BIGINT type'.  (Bug
     #19282)

   * Fixed case where driver wasn't reading server status correctly
     when fetching server-side prepared statement rows, which in some
     cases could cause warning counts to be off, or multiple result
     sets to not be read off the wire.  (Bug #19282)

   * Fixed data truncation and `getWarnings()' only returns last
     warning in set.  (Bug #18740)

   * Fixed aliased column names where length of name > 251 are
     corrupted.  (Bug #18554)

   * Improved performance of retrieving `BigDecimal', `Time',
     `Timestamp' and `Date' values from server-side prepared statements
     by creating fewer short-lived instances of `Strings' when the
     native type is not an exact match for the requested type.  (Bug
     #18496)

   * Added performance feature, re-writing of batched executes for
     `Statement.executeBatch()' (for all DML statements) and
     `PreparedStatement.executeBatch()' (for INSERTs with VALUE clauses
     only). Enable by using "rewriteBatchedStatements=true" in your
     JDBC URL.  (Bug #18041)

   * Fixed issue where server-side prepared statements don't cause
     truncation exceptions to be thrown when truncation happens.  (Bug
     #18041)

   * Fixed `CallableStatement.registerOutParameter()' not working when
     some parameters pre-populated. Still waiting for feedback from
     JDBC experts group to determine what correct parameter count from
     `getMetaData()' should be, however.  (Bug #17898)

   * Fixed calling `clearParameters()' on a closed prepared statement
     causes NPE.  (Bug #17587)

   * Map "latin1" on MySQL server to CP1252 for MySQL > 4.1.0.  (Bug
     #17587)

   * Added additional accessor and mutator methods on
     ConnectionProperties so that DataSource users can use same naming
     as regular URL properties.  (Bug #17587)

   * Fixed `ResultSet.wasNull()' not always reset correctly for
     booleans when done using conversion for server-side prepared
     statements.  (Bug #17450)

   * Fixed `Statement.getGeneratedKeys()' throws `NullPointerException'
     when no query has been processed.  (Bug #17099)

   * Fixed updatable result set doesn't return `AUTO_INCREMENT' values
     for `insertRow()' when multiple column primary keys are used. (the
     driver was checking for the existence of single-column primary
     keys and an autoincrement value > 0 instead of a straightforward
     `isAutoIncrement()' check).  (Bug #16841)

   * `DBMD.getColumns()' returns wrong type for *Note `BIT':
     numeric-types.  (Bug #15854)

   * `lib-nodist' directory missing from package breaks out-of-box
     build.  (Bug #15676)

   * Fixed issue with `ReplicationConnection' incorrectly copying
     state, doesn't transfer connection context correctly when
     transitioning between the same read-only states.  (Bug #15570)

   * No "dos" character set in MySQL > 4.1.0.  (Bug #15544)

   * `INOUT' parameter does not store `IN' value.  (Bug #15464)

   * `PreparedStatement.setObject()' serializes `BigInteger' as object,
     rather than sending as numeric value (and is thus not
     complementary to `.getObject()' on an `UNSIGNED LONG' type).  (Bug
     #15383)

   * Fixed issue where driver was unable to initialize character set
     mapping tables. Removed reliance on `.properties' files to hold
     this information, as it turns out to be too problematic to code
     around class loader hierarchies that change depending on how an
     application is deployed. Moved information back into the
     `CharsetMapping' class.  (Bug #14938)

   * Exception thrown for new decimal type when using updatable result
     sets.  (Bug #14609)

   * Driver now aware of fix for *Note `BIT': numeric-types.  type
     metadata that went into MySQL-5.0.21 for server not reporting
     length consistently .  (Bug #13601)

   * Added support for Apache Commons logging, use
     "com.mysql.jdbc.log.CommonsLogger" as the value for the "logger"
     configuration property.  (Bug #13469)

   * Fixed driver trying to call methods that don't exist on older and
     newer versions of Log4j. The fix is not trying to auto-detect
     presence of log4j, too many different incompatible versions out
     there in the wild to do this reliably.

     If you relied on autodetection before, you will need to add
     "logger=com.mysql.jdbc.log.Log4JLogger" to your JDBC URL to enable
     Log4J usage, or alternatively use the new "CommonsLogger" class to
     take care of this.  (Bug #13469)

   * LogFactory now prepends `com.mysql.jdbc.log' to the log class name
     if it cannot be found as specified. This enables you to use `short
     names' for the built-in log factories, for example,
     `logger=CommonsLogger' instead of
     `logger=com.mysql.jdbc.log.CommonsLogger'.  (Bug #13469)

   * `ResultSet.getShort()' for `UNSIGNED TINYINT' returned wrong
     values.  (Bug #11874)


File: manual.info,  Node: cj-news-3-1-12,  Next: cj-news-3-1-11,  Prev: cj-news-3-1-13,  Up: cj-news-3-1-x

D.6.3.4 Changes in MySQL Connector/J 3.1.12 (30 November 2005)
..............................................................

*Bugs Fixed*

   * Process escape tokens in `Connection.prepareStatement(...)'. You
     can disable this behavior by setting the JDBC URL configuration
     property `processEscapeCodesForPrepStmts' to `false'.  (Bug #15141)

   * Usage advisor complains about unreferenced columns, even though
     they've been referenced.  (Bug #15065)

   * Driver incorrectly closes streams passed as arguments to
     `PreparedStatements'. Reverts to legacy behavior by setting the
     JDBC configuration property `autoClosePStmtStreams' to `true'
     (also included in the 3-0-Compat configuration `bundle').  (Bug
     #15024)

   * Deadlock while closing server-side prepared statements from
     multiple threads sharing one connection.  (Bug #14972)

   * Unable to initialize character set mapping tables (due to J2EE
     classloader differences).  (Bug #14938)

   * Escape processor replaces quote character in quoted string with
     string delimiter.  (Bug #14909)

   * `DatabaseMetaData.getColumns()' doesn't return `TABLE_NAME'
     correctly.  (Bug #14815)

   * `storesMixedCaseIdentifiers()' returns `false' (Bug #14562)

   * `storesLowerCaseIdentifiers()' returns `true' (Bug #14562)

   * `storesMixedCaseQuotedIdentifiers()' returns `false' (Bug #14562)

   * `storesMixedCaseQuotedIdentifiers()' returns `true' (Bug #14562)

   * If `lower_case_table_names=0' (on server):

        * `storesLowerCaseIdentifiers()' returns `false'

        * `storesLowerCaseQuotedIdentifiers()' returns `false'

        * `storesMixedCaseIdentifiers()' returns `true'

        * `storesMixedCaseQuotedIdentifiers()' returns `true'

        * `storesUpperCaseIdentifiers()' returns `false'

        * `storesUpperCaseQuotedIdentifiers()' returns `true'

     (Bug #14562)

   * `storesUpperCaseIdentifiers()' returns `false' (Bug #14562)

   * `storesUpperCaseQuotedIdentifiers()' returns `true' (Bug #14562)

   * If `lower_case_table_names=1' (on server):

        * `storesLowerCaseIdentifiers()' returns `true'

        * `storesLowerCaseQuotedIdentifiers()' returns `true'

        * `storesMixedCaseIdentifiers()' returns `false'

        * `storesMixedCaseQuotedIdentifiers()' returns `false'

        * `storesUpperCaseIdentifiers()' returns `false'

        * `storesUpperCaseQuotedIdentifiers()' returns `true'

     (Bug #14562)

   * `storesLowerCaseQuotedIdentifiers()' returns `true' (Bug #14562)

   * Fixed `DatabaseMetaData.stores*Identifiers()':

        * If `lower_case_table_names=0' (on server):

             * `storesLowerCaseIdentifiers()' returns `false'

             * `storesLowerCaseQuotedIdentifiers()' returns `false'

             * `storesMixedCaseIdentifiers()' returns `true'

             * `storesMixedCaseQuotedIdentifiers()' returns `true'

             * `storesUpperCaseIdentifiers()' returns `false'

             * `storesUpperCaseQuotedIdentifiers()' returns `true'

        * If `lower_case_table_names=1' (on server):

             * `storesLowerCaseIdentifiers()' returns `true'

             * `storesLowerCaseQuotedIdentifiers()' returns `true'

             * `storesMixedCaseIdentifiers()' returns `false'

             * `storesMixedCaseQuotedIdentifiers()' returns `false'

             * `storesUpperCaseIdentifiers()' returns `false'

             * `storesUpperCaseQuotedIdentifiers()' returns `true'

     (Bug #14562)

   * `storesMixedCaseIdentifiers()' returns `true' (Bug #14562)

   * `storesLowerCaseQuotedIdentifiers()' returns `false' (Bug #14562)

   * Java type conversion may be incorrect for *Note `MEDIUMINT':
     numeric-types.  (Bug #14562)

   * `storesLowerCaseIdentifiers()' returns `false' (Bug #14562)

   * Added configuration property `useGmtMillisForDatetimes' which when
     set to `true' causes `ResultSet.getDate()', `.getTimestamp()' to
     return correct millis-since GMT when `.getTime()' is called on the
     return value (currently default is `false' for legacy behavior).
     (Bug #14562)

   * Extraneous sleep on `autoReconnect'.  (Bug #13775)

   * Reconnect during middle of `executeBatch()' should not occur if
     `autoReconnect' is enabled.  (Bug #13255)

   * `maxQuerySizeToLog' is not respected. Added logging of bound
     values for `execute()' phase of server-side prepared statements
     when `profileSQL=true' as well.  (Bug #13048)

   * OpenOffice expects `DBMD.supportsIntegrityEnhancementFacility()'
     to return `true' if foreign keys are supported by the datasource,
     even though this method also covers support for check constraints,
     which MySQL _doesn't_ have. Setting the configuration property
     `overrideSupportsIntegrityEnhancementFacility' to `true' causes
     the driver to return `true' for this method.  (Bug #12975)

   * Added `com.mysql.jdbc.testsuite.url.default' system property to
     set default JDBC url for testsuite (to speed up bug resolution
     when I'm working in Eclipse).  (Bug #12975)

   * `logSlowQueries' should give better info.  (Bug #12230)

   * Don't increase timeout for failover/reconnect.  (Bug #6577)

   * Fixed client-side prepared statement bug with embedded `?'
     characters inside quoted identifiers (it was recognized as a
     placeholder, when it was not).

   * Do not permit `executeBatch()' for `CallableStatements' with
     registered `OUT'/`INOUT' parameters (JDBC compliance).

   * Fall back to platform-encoding for `URLDecoder.decode()' when
     parsing driver URL properties if the platform doesn't have a
     two-argument version of this method.


File: manual.info,  Node: cj-news-3-1-11,  Next: cj-news-3-1-10,  Prev: cj-news-3-1-12,  Up: cj-news-3-1-x

D.6.3.5 Changes in MySQL Connector/J 3.1.11 (07 October 2005)
.............................................................

*Bugs Fixed*

   * The configuration property `sessionVariables' now permits you to
     specify variables that start with the ``@'' sign.  (Bug #13453)

   * URL configuration parameters do not permit ``&'' or ``='' in their
     values. The JDBC driver now parses configuration parameters as if
     they are encoded using the application/x-www-form-urlencoded
     format as specified by `java.net.URLDecoder'
     (`http://java.sun.com/j2se/1.5.0/docs/api/java/net/URLDecoder.html').

     If the ``%'' character is present in a configuration property, it
     must now be represented as `%25', which is the encoded form of
     ``%'' when using application/x-www-form-urlencoded encoding.  (Bug
     #13453)

   * Workaround for Bug #13374: `ResultSet.getStatement()' on closed
     result set returns `NULL' (as per JDBC 4.0 spec, but not
     backward-compatible). Set the connection property
     `retainStatementAfterResultSetClose' to `true' to be able to
     retrieve a `ResultSet''s statement after the `ResultSet' has been
     closed using `.getStatement()' (the default is `false', to be
     JDBC-compliant and to reduce the chance that code using JDBC leaks
     `Statement' instances).  (Bug #13277)

   * `ResultSetMetaData' from `Statement.getGeneratedKeys()' caused a
     `NullPointerException' to be thrown whenever a method that
     required a connection reference was called.  (Bug #13277)

   * Backport of `VAR[BINARY|CHAR] [BINARY]' types detection from 5.0
     branch.  (Bug #13277)

   * Fixed `NullPointerException' when converting `catalog' parameter
     in many `DatabaseMetaDataMethods' to `byte[]'s (for the result
     set) when the parameter is `null'. (`null' is not technically
     permitted by the JDBC specification, but we have historically
     permitted it).  (Bug #13277)

   * Backport of `Field' class,
     `ResultSetMetaData.getColumnClassName()', and
     `ResultSet.getObject(int)' changes from 5.0 branch to fix behavior
     surrounding `VARCHAR BINARY'/*Note `VARBINARY': binary-varbinary.
     and related types.  (Bug #13277)

   * Read response in `MysqlIO.sendFileToServer()', even if the local
     file can't be opened, otherwise next query issued will fail,
     because it is reading the response to the empty *Note `LOAD DATA
     INFILE': load-data. packet sent to the server.  (Bug #13277)

   * When `gatherPerfMetrics' is enabled for servers older than 4.1.0,
     a `NullPointerException' is thrown from the constructor of
     `ResultSet' if the query doesn't use any tables.  (Bug #13043)

   * `java.sql.Types.OTHER' returned for *Note `BINARY':
     binary-varbinary. and *Note `VARBINARY': binary-varbinary. columns
     when using `DatabaseMetaData.getColumns()'.  (Bug #12970)

   * `ServerPreparedStatement.getBinding()' now checks if the statement
     is closed before attempting to reference the list of parameter
     bindings, to avoid throwing a `NullPointerException'.  (Bug #12970)

   * Tokenizer for `=' in URL properties was causing
     `sessionVariables=....' to be parameterized incorrectly.  (Bug
     #12753)

   * `cp1251' incorrectly mapped to `win1251' for servers newer than
     4.0.x.  (Bug #12752)

   * `getExportedKeys()' (Bug #12541)

   * Specifying a catalog works as stated in the API docs.  (Bug #12541)

   * Specifying `NULL' means that catalog will not be used to filter
     the results (thus all databases will be searched), unless you've
     set `nullCatalogMeansCurrent=true' in your JDBC URL properties.
     (Bug #12541)

   * `getIndexInfo()' (Bug #12541)

   * `getProcedures()' (and thus indirectly `getProcedureColumns()')
     (Bug #12541)

   * `getImportedKeys()' (Bug #12541)

   * Specifying `""' means `current' catalog, even though this isn't
     quite JDBC spec compliant, it is there for legacy users.  (Bug
     #12541)

   * `getCrossReference()' (Bug #12541)

   * Added `Connection.isMasterConnection()' for clients to be able to
     determine if a multi-host master/slave connection is connected to
     the first host in the list.  (Bug #12541)

   * `getColumns()' (Bug #12541)

   * Handling of catalog argument in `DatabaseMetaData.getIndexInfo()',
     which also means changes to the following methods in
     `DatabaseMetaData':

        * `getBestRowIdentifier()'

        * `getColumns()'

        * `getCrossReference()'

        * `getExportedKeys()'

        * `getImportedKeys()'

        * `getIndexInfo()'

        * `getPrimaryKeys()'

        * `getProcedures()' (and thus indirectly
          `getProcedureColumns()')

        * `getTables()'

     The `catalog' argument in all of these methods now behaves in the
     following way:

        * Specifying `NULL' means that catalog will not be used to
          filter the results (thus all databases will be searched),
          unless you've set `nullCatalogMeansCurrent=true' in your JDBC
          URL properties.

        * Specifying `""' means `current' catalog, even though this
          isn't quite JDBC spec compliant, it is there for legacy users.

        * Specifying a catalog works as stated in the API docs.

        * Made `Connection.clientPrepare()' available from `wrapped'
          connections in the `jdbc2.optional' package (connections built
          by `ConnectionPoolDataSource' instances).

     (Bug #12541)

   * `getBestRowIdentifier()' (Bug #12541)

   * Made `Connection.clientPrepare()' available from `wrapped'
     connections in the `jdbc2.optional' package (connections built by
     `ConnectionPoolDataSource' instances).  (Bug #12541)

   * `getTables()' (Bug #12541)

   * `getPrimaryKeys()' (Bug #12541)

   * `Connection.prepareCall()' is database name case-sensitive (on
     Windows systems).  (Bug #12417)

   * `explainSlowQueries' hangs with server-side prepared statements.
     (Bug #12229)

   * Properties shared between master and slave with replication
     connection.  (Bug #12218)

   * Geometry types not handled with server-side prepared statements.
     (Bug #12104)

   * `maxPerformance.properties' mis-spells `elideSetAutoCommits'.
     (Bug #11976)

   * `ReplicationConnection' won't switch to slave, throws `Catalog
     can't be null' exception.  (Bug #11879)

   * `Pstmt.setObject(...., Types.BOOLEAN)' throws exception.  (Bug
     #11798)

   * Escape tokenizer doesn't respect stacked single quotation marks
     for escapes.  (Bug #11797)

   * `GEOMETRY' type not recognized when using server-side prepared
     statements.  (Bug #11797)

   * Foreign key information that is quoted is parsed incorrectly when
     `DatabaseMetaData' methods use that information.  (Bug #11781)

   * The `sendBlobChunkSize' property is now clamped to
     `max_allowed_packet' with consideration of stream buffer size and
     packet headers to avoid `PacketTooBigExceptions' when
     `max_allowed_packet' is similar in size to the default
     `sendBlobChunkSize' which is 1M.  (Bug #11781)

   * `CallableStatement.clearParameters()' now clears resources
     associated with `INOUT'/`OUTPUT' parameters as well as `INPUT'
     parameters.  (Bug #11781)

   * Fixed regression caused by fix for Bug #11552 that caused driver
     to return incorrect values for unsigned integers when those
     integers where within the range of the positive signed type.  (Bug
     #11663)

   * Moved source code to Subversion repository.  (Bug #11663)

   * Incorrect generation of testcase scripts for server-side prepared
     statements.  (Bug #11663)

   * Fixed statements generated for testcases missing `;' for `plain'
     statements.  (Bug #11629)

   * Spurious `!' on console when character encoding is `utf8'.  (Bug
     #11629)

   * `StringUtils.getBytes()' doesn't work when using multi-byte
     character encodings and a length in _characters_ is specified.
     (Bug #11614)

   * `DBMD.storesLower/Mixed/UpperIdentifiers()' reports incorrect
     values for servers deployed on Windows.  (Bug #11575)

   * Reworked `Field' class, `*Buffer', and `MysqlIO' to be aware of
     field lengths > `Integer.MAX_VALUE'.  (Bug #11498)

   * Escape processor didn't honor strings demarcated with double
     quotation marks.  (Bug #11498)

   * Updated `DBMD.supportsCorrelatedQueries()' to return `true' for
     versions > 4.1, `supportsGroupByUnrelated()' to return `true' and
     `getResultSetHoldability()' to return `HOLD_CURSORS_OVER_COMMIT'.
     (Bug #11498)

   * Lifted restriction of changing streaming parameters with
     server-side prepared statements. As long as `all' streaming
     parameters were set before execution, `.clearParameters()' does
     not have to be called. (due to limitation of client/server
     protocol, prepared statements can not reset _individual_ stream
     data on the server side).  (Bug #11498)

   * `ResultSet.moveToCurrentRow()' fails to work when preceded by a
     call to `ResultSet.moveToInsertRow()'.  (Bug #11190)

   * *Note `VARBINARY': binary-varbinary. data corrupted when using
     server-side prepared statements and `.setBytes()'.  (Bug #11115)

   * `Statement.getWarnings()' fails with NPE if statement has been
     closed.  (Bug #10630)

   * Only get `char[]' from SQL in `PreparedStatement.ParseInfo()' when
     needed.  (Bug #10630)


File: manual.info,  Node: cj-news-3-1-10,  Next: cj-news-3-1-9,  Prev: cj-news-3-1-11,  Up: cj-news-3-1-x

D.6.3.6 Changes in MySQL Connector/J 3.1.10 (23 June 2005)
..........................................................

*Bugs Fixed*

   * Initial implemention of `ParameterMetadata' for
     `PreparedStatement.getParameterMetadata()'.  Only works fully for
     `CallableStatements', as current server-side prepared statements
     return every parameter as a *Note `VARCHAR': char. type.

   * Fixed connecting without a database specified raised an exception
     in `MysqlIO.changeDatabaseTo()'.


File: manual.info,  Node: cj-news-3-1-9,  Next: cj-news-3-1-8,  Prev: cj-news-3-1-10,  Up: cj-news-3-1-x

D.6.3.7 Changes in MySQL Connector/J 3.1.9 (22 June 2005)
.........................................................

*Bugs Fixed*

   * Production package doesn't include JBoss integration classes.
     (Bug #11411)

   * Removed nonsensical `costly type conversion' warnings when using
     usage advisor.  (Bug #11411)

   * Fixed `PreparedStatement.setClob()' not accepting `null' as a
     parameter.  (Bug #11360)

   * Connector/J dumping query into `SQLException' twice.  (Bug #11360)

   * `autoReconnect' ping causes exception on connection startup.  (Bug
     #11259)

   * `Connection.setCatalog()' is now aware of the
     `useLocalSessionState' configuration property, which when set to
     `true' will prevent the driver from sending `USE ...' to the
     server if the requested catalog is the same as the current catalog.
     (Bug #11115)

   * `3-0-Compat': Compatibility with Connector/J 3.0.x functionality
     (Bug #11115)

   * `maxPerformance': Maximum performance without being reckless (Bug
     #11115)

   * `solarisMaxPerformance': Maximum performance for Solaris, avoids
     syscalls where it can (Bug #11115)

   * Added `maintainTimeStats' configuration property (defaults to
     `true'), which tells the driver whether or not to keep track of
     the last query time and the last successful packet sent to the
     server's time. If set to `false', removes two syscalls per query.
     (Bug #11115)

   * *Note `VARBINARY': binary-varbinary. data corrupted when using
     server-side prepared statements and `ResultSet.getBytes()'.  (Bug
     #11115)

   * Added the following configuration bundles, use one or many using
     the `useConfigs' configuration property:

        * `maxPerformance': Maximum performance without being reckless

        * `solarisMaxPerformance': Maximum performance for Solaris,
          avoids syscalls where it can

        * `3-0-Compat': Compatibility with Connector/J 3.0.x
          functionality

     (Bug #11115)

   * Try to handle `OutOfMemoryErrors' more gracefully. Although not
     much can be done, they will in most cases close the connection
     they happened on so that further operations don't run into a
     connection in some unknown state.  When an OOM has happened, any
     further operations on the connection will fail with a `Connection
     closed' exception that will also list the OOM exception as the
     reason for the implicit connection close event.  (Bug #10850)

   * Setting `cachePrepStmts=true' now causes the `Connection' to also
     cache the check the driver performs to determine if a prepared
     statement can be server-side or not, as well as caches server-side
     prepared statements for the lifetime of a connection. As before,
     the `prepStmtCacheSize' parameter controls the size of these
     caches.  (Bug #10850)

   * Don't send `COM_RESET_STMT' for each execution of a server-side
     prepared statement if it isn't required.  (Bug #10850)

   * 0-length streams not sent to server when using server-side
     prepared statements.  (Bug #10850)

   * Driver detects if you're running MySQL-5.0.7 or later, and does
     not scan for `LIMIT ?[,?]' in statements being prepared, as the
     server supports those types of queries now.  (Bug #10850)

   * Reorganized directory layout. Sources now are in `src' folder.
     Don't pollute parent directory when building, now output goes to
     `./build', distribution goes to `./dist'.  (Bug #10496)

   * Added support/bug hunting feature that generates `.sql' test
     scripts to `STDERR' when `autoGenerateTestcaseScript' is set to
     `true'.  (Bug #10496)

   * `SQLException' is thrown when using property `characterSetResults'
     with `cp932' or `eucjpms'.  (Bug #10496)

   * The data type returned for `TINYINT(1)' columns when
     `tinyInt1isBit=true' (the default) can be switched between
     `Types.BOOLEAN' and `Types.BIT' using the new configuration
     property `transformedBitIsBoolean', which defaults to `false'. If
     set to `false' (the default), `DatabaseMetaData.getColumns()' and
     `ResultSetMetaData.getColumnType()' will return `Types.BOOLEAN' for
     `TINYINT(1)' columns. If `true', `Types.BOOLEAN' will be returned
     instead. Regardless of this configuration property, if
     `tinyInt1isBit' is enabled, columns with the type `TINYINT(1)'
     will be returned as `java.lang.Boolean' instances from
     `ResultSet.getObject(...)', and
     `ResultSetMetaData.getColumnClassName()' will return
     `java.lang.Boolean'.  (Bug #10485)

   * `SQLException' thrown when retrieving `YEAR(2)' with
     `ResultSet.getString()'. The driver will now always treat *Note
     `YEAR': year. types as `java.sql.Dates' and return the correct
     values for `getString()'. Alternatively, the `yearIsDateType'
     connection property can be set to `false' and the values will be
     treated as `SHORT's.  (Bug #10485)

   * Driver doesn't support `{?=CALL(...)}' for calling stored
     functions. This involved adding support for function retrieval to
     `DatabaseMetaData.getProcedures()' and `getProcedureColumns()' as
     well.  (Bug #10310)

   * Unsigned *Note `SMALLINT': numeric-types. treated as signed for
     `ResultSet.getInt()', fixed all cases for `UNSIGNED' integer
     values and server-side prepared statements, as well as
     `ResultSet.getObject()' for `UNSIGNED TINYINT'.  (Bug #10156)

   * Made `ServerPreparedStatement.asSql()' work correctly so
     auto-explain functionality would work with server-side prepared
     statements.  (Bug #10155)

   * Double quotation marks not recognized when parsing client-side
     prepared statements.  (Bug #10155)

   * Made JDBC2-compliant wrappers public to enable access to vendor
     extensions.  (Bug #10155)

   * `DatabaseMetaData.supportsMultipleOpenResults()' now returns
     `true'. The driver has supported this for some time, DBMD just
     missed that fact.  (Bug #10155)

   * Cleaned up logging of profiler events, moved code to dump a
     profiler event as a string to `com.mysql.jdbc.log.LogUtils' so
     that third parties can use it.  (Bug #10155)

   * Made `enableStreamingResults()' visible on
     `com.mysql.jdbc.jdbc2.optional.StatementWrapper'.  (Bug #10155)

   * Actually write manifest file to correct place so it ends up in the
     binary jar file.  (Bug #10144)

   * Added `createDatabaseIfNotExist' property (default is `false'),
     which will cause the driver to ask the server to create the
     database specified in the URL if it doesn't exist. You must have
     the appropriate privileges for database creation for this to work.
     (Bug #10144)

   * Memory leak in `ServerPreparedStatement' if `serverPrepare()'
     fails.  (Bug #10144)

   * `com.mysql.jdbc.PreparedStatement.ParseInfo' does unnecessary call
     to `toCharArray()'.  (Bug #9064)

   * Driver now correctly uses CP932 if available on the server for
     Windows-31J, CP932 and MS932 java encoding names, otherwise it
     resorts to SJIS, which is only a close approximation. Currently
     only MySQL-5.0.3 and newer (and MySQL-4.1.12 or .13, depending on
     when the character set gets backported) can reliably support any
     variant of CP932.

   * Overhaul of character set configuration, everything now lives in a
     properties file.


File: manual.info,  Node: cj-news-3-1-8,  Next: cj-news-3-1-7,  Prev: cj-news-3-1-9,  Up: cj-news-3-1-x

D.6.3.8 Changes in MySQL Connector/J 3.1.8 (14 April 2005)
..........................................................

*Bugs Fixed*

   * Should accept `null' for catalog (meaning use current) in DBMD
     methods, even though it is not JDBC-compliant for legacy's sake.
     Disable by setting connection property `nullCatalogMeansCurrent' to
     `false' (which will be the default value in C/J 3.2.x).  (Bug
     #9917)

   * Fixed driver not returning `true' for `-1' when
     `ResultSet.getBoolean()' was called on result sets returned from
     server-side prepared statements.  (Bug #9778)

   * Added a `Manifest.MF' file with implementation information to the
     `.jar' file.  (Bug #9778)

   * More tests in `Field.isOpaqueBinary()' to distinguish opaque
     binary (that is, fields with type `CHAR(n)' and `CHARACTER SET
     BINARY') from output of various scalar and aggregate functions
     that return strings.  (Bug #9778)

   * `DBMD.getTables()' shouldn't return tables if views are asked for,
     even if the database version doesn't support views.  (Bug #9778)

   * Should accept `null' for name patterns in DBMD (meaning ``%''),
     even though it isn't JDBC compliant, for legacy's sake. Disable by
     setting connection property `nullNamePatternMatchesAll' to `false'
     (which will be the default value in C/J 3.2.x).  (Bug #9769)

   * The performance metrics feature now gathers information about
     number of tables referenced in a SELECT.  (Bug #9704)

   * The logging system is now automatically configured. If the value
     has been set by the user, using the URL property `logger' or the
     system property `com.mysql.jdbc.logger', then use that, otherwise,
     autodetect it using the following steps:

       1. Log4j, if it is available,

       2. Then JDK1.4 logging,

       3. Then fallback to our `STDERR' logging.

     (Bug #9704)

   * `Statement.getMoreResults()' could throw NPE when existing result
     set was `.close()'d.  (Bug #9704)

   * Stored procedures with *Note `DECIMAL': numeric-types.  parameters
     with storage specifications that contained ``,'' in them would
     fail.  (Bug #9682)

   * `PreparedStatement.setObject(int, Object, int type, int scale)'
     now uses scale value for `BigDecimal' instances.  (Bug #9682)

   * Added support for the c3p0 connection pool's
     (`http://c3p0.sf.net/') validation/connection checker interface
     which uses the lightweight `COM_PING' call to the server if
     available. To use it, configure your c3p0 connection pool's
     `connectionTesterClassName' property to use
     `com.mysql.jdbc.integration.c3p0.MysqlConnectionTester'.  (Bug
     #9320)

   * `PreparedStatement.getMetaData()' inserts blank row in database
     under certain conditions when not using server-side prepared
     statements.  (Bug #9320)

   * Better detection of `LIMIT' inside/outside of quoted strings so
     that the driver can more correctly determine whether a prepared
     statement can be prepared on the server or not.  (Bug #9320)

   * `Connection.canHandleAsPreparedStatement()' now makes `best
     effort' to distinguish `LIMIT' clauses with placeholders in them
     from ones without to have fewer false positives when generating
     work-arounds for statements the server cannot currently handle as
     server-side prepared statements.  (Bug #9320)

   * Fixed `build.xml' to not compile `log4j' logging if `log4j' not
     available.  (Bug #9320)

   * Added finalizers to `ResultSet' and `Statement' implementations to
     be JDBC spec-compliant, which requires that if not explicitly
     closed, these resources should be closed upon garbage collection.
     (Bug #9319)

   * Stored procedures with same name in different databases confuse
     the driver when it tries to determine parameter counts/types.
     (Bug #9319)

   * A continuation of Bug #8868, where functions used in queries that
     should return nonstring types when resolved by temporary tables
     suddenly become opaque binary strings (work-around for server
     limitation). Also fixed fields with type of `CHAR(n) CHARACTER SET
     BINARY' to return correct/matching classes for
     `RSMD.getColumnClassName()' and `ResultSet.getObject()'.  (Bug
     #9236)

   * Cannot use `UTF-8' for characterSetResults configuration property.
     (Bug #9206)

   * `PreparedStatement.addBatch()' doesn't work with server-side
     prepared statements and streaming *Note `BINARY':
     binary-varbinary. data.  (Bug #9040)

   * `ServerPreparedStatements' now correctly `stream' *Note `BLOB':
     blob./`CLOB' data to the server. You can configure the threshold
     chunk size using the JDBC URL property `blobSendChunkSize' (the
     default is 1MB).  (Bug #8868)

   * `DATE_FORMAT()' queries returned as *Note `BLOB': blob.s from
     `getObject()'.  (Bug #8868)

   * Server-side session variables can be preset at connection time by
     passing them as a comma-delimited list for the connection property
     `sessionVariables'.  (Bug #8868)

   * `BlobFromLocator' now uses correct identifier quoting when
     generating prepared statements.  (Bug #8868)

   * Fixed regression in `ping()' for users using `autoReconnect=true'.
     (Bug #8868)

   * Check for empty strings (`''') when converting *Note `CHAR':
     char./*Note `VARCHAR': char.  column data to numbers, throw
     exception if `emptyStringsConvertToZero' configuration property is
     set to `false' (for backward-compatibility with 3.0, it is now set
     to `true' by default, but will most likely default to `false' in
     3.2).  (Bug #8803)

   * `DATA_TYPE' column from `DBMD.getBestRowIdentifier()' causes
     `ArrayIndexOutOfBoundsException' when accessed (and in fact,
     didn't return any value).  (Bug #8803)

   * `DBMD.supportsMixedCase*Identifiers()' returns wrong value on
     servers running on case-sensitive file systems.  (Bug #8800)

   * `DBMD.supportsResultSetConcurrency()' not returning `true' for
     forward-only/read-only result sets (we obviously support this).
     (Bug #8792)

   * Fixed `ResultSet.getTime()' on a `NULL' value for server-side
     prepared statements throws NPE.

   * Made `Connection.ping()' a public method.

   * Added support for new precision-math *Note `DECIMAL':
     numeric-types. type in MySQL 5.0.3 and up.

   * Fixed `DatabaseMetaData.getTables()' returning views when they
     were not asked for as one of the requested table types.


File: manual.info,  Node: cj-news-3-1-7,  Next: cj-news-3-1-6,  Prev: cj-news-3-1-8,  Up: cj-news-3-1-x

D.6.3.9 Changes in MySQL Connector/J 3.1.7 (18 February 2005)
.............................................................

*Bugs Fixed*

   * `PreparedStatements' not creating streaming result sets.  (Bug
     #8487)

   * Don't pass `NULL' to `String.valueOf()' in
     `ResultSet.getNativeConvertToString()', as it stringifies it (that
     is, returns `null'), which is not correct for the method in
     question.  (Bug #8487)

   * Fixed NPE in `ResultSet.realClose()' when using usage advisor and
     result set was already closed.  (Bug #8428)

   * `ResultSet.getString()' doesn't maintain format stored on server,
     bug fix only enabled when `noDatetimeStringSync' property is set to
     `true' (the default is `false').  (Bug #8428)

   * Added support for *Note `BIT': numeric-types. type in MySQL-5.0.3.
     The driver will treat `BIT(1-8)' as the JDBC standard *Note `BIT':
     numeric-types. type (which maps to `java.lang.Boolean'), as the
     server does not currently send enough information to determine the
     size of a bitfield when < 9 bits are declared.  `BIT(>9)' will be
     treated as *Note `VARBINARY': binary-varbinary, and will return
     `byte[]' when `getObject()' is called.  (Bug #8424)

   * Added `useLocalSessionState' configuration property, when set to
     `true' the JDBC driver trusts that the application is well-behaved
     and only sets autocommit and transaction isolation levels using
     the methods provided on `java.sql.Connection', and therefore can
     manipulate these values in many cases without incurring
     round-trips to the database server.  (Bug #8424)

   * Added `enableStreamingResults()' to `Statement' for connection
     pool implementations that check `Statement.setFetchSize()' for
     specification-compliant values. Call `Statement.setFetchSize(>=0)'
     to disable the streaming results for that statement.  (Bug #8424)

   * `ResultSet.getBigDecimal()' throws exception when rounding would
     need to occur to set scale. The driver now chooses a rounding mode
     of `half up' if nonrounding `BigDecimal.setScale()' fails.  (Bug
     #8424)

   * Fixed synchronization issue with
     `ServerPreparedStatement.serverPrepare()' that could cause
     deadlocks/crashes if connection was shared between threads.  (Bug
     #8096)

   * Emulated locators corrupt binary data when using server-side
     prepared statements.  (Bug #8096)

   * Infinite recursion when `falling back' to master in failover
     configuration.  (Bug #7952)

   * Disable multi-statements (if enabled) for MySQL-4.1 versions prior
     to version 4.1.10 if the query cache is enabled, as the server
     returns wrong results in this configuration.  (Bug #7952)

   * Removed `dontUnpackBinaryResults' functionality, the driver now
     always stores results from server-side prepared statements as is
     from the server and unpacks them on demand.  (Bug #7952)

   * Fixed duplicated code in `configureClientCharset()' that prevented
     `useOldUTF8Behavior=true' from working properly.  (Bug #7952)

   * Added `holdResultsOpenOverStatementClose' property (default is
     `false'), that keeps result sets open over statement.close() or
     new execution on same statement (suggested by Kevin Burton).  (Bug
     #7715)

   * Detect new `sql_mode' variable in string form (it used to be
     integer) and adjust quoting method for strings appropriately.
     (Bug #7715)

   * Timestamps converted incorrectly to strings with server-side
     prepared statements and updatable result sets.  (Bug #7715)

   * Timestamp key column data needed `_binary' stripped for
     `UpdatableResultSet.refreshRow()'.  (Bug #7686)

   * Choose correct `direction' to apply time adjustments when both
     client and server are in GMT time zone when using
     `ResultSet.get(..., cal)' and `PreparedStatement.set(...., cal)'.
     (Bug #4718)

   * Remove `_binary' introducer from parameters used as in/out
     parameters in `CallableStatement'.  (Bug #4718)

   * Always return `byte[]'s for output parameters registered as
     `*BINARY'.  (Bug #4718)

   * By default, the driver now scans SQL you are preparing using all
     variants of `Connection.prepareStatement()' to determine if it is
     a supported type of statement to prepare on the server side, and
     if it is not supported by the server, it instead prepares it as a
     client-side emulated prepared statement. You can disable this by
     passing `emulateUnsupportedPstmts=false' in your JDBC URL.  (Bug
     #4718)

   * Added `dontTrackOpenResources' option (default is `false', to be
     JDBC compliant), which helps with memory use for nonwell-behaved
     apps (that is, applications that don't close `Statement' objects
     when they should).  (Bug #4718)

   * Send correct value for `boolean' `true' to server for
     `PreparedStatement.setObject(n, "true", Types.BIT)'.  (Bug #4718)

   * Fixed bug with Connection not caching statements from
     `prepareStatement()' when the statement wasn't a server-side
     prepared statement.  (Bug #4718)


File: manual.info,  Node: cj-news-3-1-6,  Next: cj-news-3-1-5,  Prev: cj-news-3-1-7,  Up: cj-news-3-1-x

D.6.3.10 Changes in MySQL Connector/J 3.1.6 (23 December 2004)
..............................................................

*Bugs Fixed*

   * `DBMD.getProcedures()' doesn't respect catalog parameter.  (Bug
     #7026)

   * Fixed hang on `SocketInputStream.read()' with
     `Statement.setMaxRows()' and multiple result sets when driver has
     to truncate result set directly, rather than tacking a `LIMIT N'
     on the end of it.


File: manual.info,  Node: cj-news-3-1-5,  Next: cj-news-3-1-4,  Prev: cj-news-3-1-6,  Up: cj-news-3-1-x

D.6.3.11 Changes in MySQL Connector/J 3.1.5 (02 December 2004)
..............................................................

*Bugs Fixed*

   * Use 1MB packet for sending file for *Note `LOAD DATA LOCAL
     INFILE': load-data. if that is < `max_allowed_packet' on server.
     (Bug #6537)

   * `SUM()' on *Note `DECIMAL': numeric-types. with server-side
     prepared statement ignores scale if zero-padding is needed (this
     ends up being due to conversion to *Note `DOUBLE': numeric-types.
     by server, which when converted to a string to parse into
     `BigDecimal', loses all `padding' zeros).  (Bug #6537)

   * Use `DatabaseMetaData.getIdentifierQuoteString()' when building
     DBMD queries.  (Bug #6537)

   * Use our own implementation of buffered input streams to get around
     blocking behavior of `java.io.BufferedInputStream'. Disable this
     with `useReadAheadInput=false'.  (Bug #6399)

   * Make auto-deserialization of `java.lang.Objects' stored in *Note
     `BLOB': blob. columns configurable using `autoDeserialize'
     property (defaults to `false').  (Bug #6399)

   * `ResultSetMetaData.getColumnDisplaySize()' returns incorrect
     values for multi-byte charsets.  (Bug #6399)

   * Re-work `Field.isOpaqueBinary()' to detect `CHAR(N) CHARACTER SET
     BINARY' to support fixed-length binary fields for
     `ResultSet.getObject()'.  (Bug #6399)

   * Failing to connect to the server when one of the addresses for the
     given host name is IPV6 (which the server does not yet bind on).
     The driver now loops through _all_ IP addresses for a given host,
     and stops on the first one that `accepts()' a `socket.connect()'.
     (Bug #6348)

   * Removed unwanted new `Throwable()' in `ResultSet' constructor due
     to bad merge (caused a new object instance that was never used for
     every result set created). Found while profiling for Bug #6359.
     (Bug #6225)

   * `ServerSidePreparedStatement' allocating short-lived objects
     unnecessarily.  (Bug #6225)

   * Use null-safe-equals for key comparisons in updatable result sets.
     (Bug #6225)

   * Fixed too-early creation of `StringBuffer' in
     `EscapeProcessor.escapeSQL()', also return `String' when escaping
     not needed (to avoid unnecessary object allocations). Found while
     profiling for Bug #6359.  (Bug #6225)

   * `UNSIGNED BIGINT' unpacked incorrectly from server-side prepared
     statement result sets.  (Bug #5729)

   * Added experimental configuration property
     `dontUnpackBinaryResults', which delays unpacking binary result
     set values until they're asked for, and only creates object
     instances for nonnumeric values (it is set to `false' by default).
     For some usecase/jvm combinations, this is friendlier on the
     garbage collector.  (Bug #5706)

   * Don't throw exceptions for `Connection.releaseSavepoint()'.  (Bug
     #5706)

   * Inefficient detection of pre-existing string instances in
     `ResultSet.getNativeString()'.  (Bug #5706)

   * Use a per-session `Calendar' instance by default when decoding
     dates from `ServerPreparedStatements' (set to old, less performant
     behavior by setting property `dynamicCalendars=true').  (Bug #5706)

   * Fixed batched updates with server prepared statements weren't
     looking if the types had changed for a given batched set of
     parameters compared to the previous set, causing the server to
     return the error `Wrong arguments to mysql_stmt_execute()'.  (Bug
     #5235)

   * Handle case when string representation of timestamp contains
     trailing ``.'' with no numbers following it.  (Bug #5235)

   * Server-side prepared statements did not honor
     `zeroDateTimeBehavior' property, and would cause class-cast
     exceptions when using `ResultSet.getObject()', as the all-zero
     string was always returned.  (Bug #5235)

   * Fix comparisons made between string constants and dynamic strings
     that are converted with either `toUpperCase()' or `toLowerCase()'
     to use `Locale.ENGLISH', as some locales `override' case rules for
     English. Also use `StringUtils.indexOfIgnoreCase()' instead of
     `.toUpperCase().indexOf()', avoids creating a very short-lived
     transient `String' instance.


File: manual.info,  Node: cj-news-3-1-4,  Next: cj-news-3-1-3,  Prev: cj-news-3-1-5,  Up: cj-news-3-1-x

D.6.3.12 Changes in MySQL Connector/J 3.1.4 (04 September 2004)
...............................................................

*Bugs Fixed*

   * Fixed `ServerPreparedStatement' to read prepared statement
     metadata off the wire, even though it is currently a placeholder
     instead of using `MysqlIO.clearInputStream()' which didn't work at
     various times because data wasn't available to read from the
     server yet. This fixes sporadic errors users were having with
     `ServerPreparedStatements' throwing
     `ArrayIndexOutOfBoundExceptions'.  (Bug #5032)

   * Added three ways to deal with all-zero datetimes when reading them
     from a `ResultSet': `exception' (the default), which throws an
     `SQLException' with an SQLState of `S1009'; `convertToNull', which
     returns `NULL' instead of the date; and `round', which rounds the
     date to the nearest closest value which is `'0001-01-01''.  (Bug
     #5032)

   * The driver is more strict about truncation of numerics on
     `ResultSet.get*()', and will throw an `SQLException' when
     truncation is detected. You can disable this by setting
     `jdbcCompliantTruncation' to `false' (it is enabled by default, as
     this functionality is required for JDBC compliance).  (Bug #5032)

   * You can now use URLs in *Note `LOAD DATA LOCAL INFILE': load-data.
     statements, and the driver will use Java's built-in handlers for
     retrieving the data and sending it to the server. This feature is
     not enabled by default, you must set the `allowUrlInLocalInfile'
     connection property to `true'.  (Bug #5032)

   * `ResultSet.getObject()' doesn't return type `Boolean' for
     pseudo-bit types from prepared statements on 4.1.x (shortcut for
     avoiding extra type conversion when using binary-encoded result
     sets obscured test in `getObject()' for `pseudo' bit type).  (Bug
     #5032)

   * Use `com.mysql.jdbc.Message''s classloader when loading resource
     bundle, should fix sporadic issues when the caller's classloader
     can't locate the resource bundle.  (Bug #5032)

   * `ServerPreparedStatements' dealing with return of *Note `DECIMAL':
     numeric-types. type don't work.  (Bug #5012)

   * Track packet sequence numbers if `enablePacketDebug=true', and
     throw an exception if packets received out-of-order.  (Bug #4689)

   * `ResultSet.wasNull()' does not work for primitives if a previous
     `null' was returned.  (Bug #4689)

   * Optimized integer number parsing, enable `old' slower integer
     parsing using JDK classes using `useFastIntParsing=false' property.
     (Bug #4642)

   * Added `useOnlyServerErrorMessages' property, which causes message
     text in exceptions generated by the server to only contain the
     text sent by the server (as opposed to the SQLState's `standard'
     description, followed by the server's error message). This
     property is set to `true' by default.  (Bug #4642)

   * `ServerPreparedStatement.execute*()' sometimes threw
     `ArrayIndexOutOfBoundsException' when unpacking field metadata.
     (Bug #4642)

   * Connector/J 3.1.3 beta does not handle integers correctly (caused
     by changes to support unsigned reads in `Buffer.readInt()' ->
     `Buffer.readShort()').  (Bug #4510)

   * Added support in `DatabaseMetaData.getTables()' and
     `getTableTypes()' for views, which are now available in MySQL
     server 5.0.x.  (Bug #4510)

   * `ResultSet.getObject()' returns wrong type for strings when using
     prepared statements.  (Bug #4482)

   * Calling `MysqlPooledConnection.close()' twice (even though an
     application error), caused NPE. Fixed.  (Bug #4482)


File: manual.info,  Node: cj-news-3-1-3,  Next: cj-news-3-1-2,  Prev: cj-news-3-1-4,  Up: cj-news-3-1-x

D.6.3.13 Changes in MySQL Connector/J 3.1.3 (07 July 2004)
..........................................................

*Bugs Fixed*

   * Support new time zone variables in MySQL-4.1.3 when
     `useTimezone=true'.  (Bug #4311)

   * Error in retrieval of `mediumint' column with prepared statements
     and binary protocol.  (Bug #4311)

   * Support for unsigned numerics as return types from prepared
     statements. This also causes a change in `ResultSet.getObject()'
     for the `bigint unsigned' type, which used to return `BigDecimal'
     instances, it now returns instances of `java.lang.BigInteger'.
     (Bug #4311)

   * Externalized more messages (on-going effort).  (Bug #4119)

   * Null bitmask sent for server-side prepared statements was
     incorrect.  (Bug #4119)

   * Added constants for MySQL error numbers (publicly accessible, see
     `com.mysql.jdbc.MysqlErrorNumbers'), and the ability to generate
     the mappings of vendor error codes to SQLStates that the driver
     uses (for documentation purposes).  (Bug #4119)

   * Added packet debugging code (see the `enablePacketDebug' property
     documentation).  (Bug #4119)

   * Use SQL Standard SQL states by default, unless `useSqlStateCodes'
     property is set to `false'.  (Bug #4119)

   * Mangle output parameter names for `CallableStatements' so they
     will not clash with user variable names.

   * Added support for `INOUT' parameters in `CallableStatements'.


File: manual.info,  Node: cj-news-3-1-2,  Next: cj-news-3-1-1,  Prev: cj-news-3-1-3,  Up: cj-news-3-1-x

D.6.3.14 Changes in MySQL Connector/J 3.1.2 (09 June 2004)
..........................................................

*Bugs Fixed*

   * Don't enable server-side prepared statements for server version
     5.0.0 or 5.0.1, as they aren't compatible with the '4.1.2+' style
     that the driver uses (the driver expects information to come back
     that isn't there, so it hangs).  (Bug #3804)

   * `getWarnings()' returns `SQLWarning' instead of `DataTruncation'.
     (Bug #3804)

   * `getProcedureColumns()' doesn't work with wildcards for procedure
     name.  (Bug #3540)

   * `getProcedures()' does not return any procedures in result set.
     (Bug #3539)

   * Fixed `DatabaseMetaData.getProcedures()' when run on MySQL-5.0.0
     (output of *Note `SHOW PROCEDURE STATUS': show-procedure-status.
     changed between 5.0.0 and 5.0.1.  (Bug #3520)

   * Added `connectionCollation' property to cause driver to issue `set
     collation_connection=...' query on connection init if default
     collation for given charset is not appropriate.  (Bug #3520)

   * `DBMD.getSQLStateType()' returns incorrect value.  (Bug #3520)

   * Correctly map output parameters to position given in
     `prepareCall()' versus. order implied during
     `registerOutParameter()'.  (Bug #3146)

   * Cleaned up detection of server properties.  (Bug #3146)

   * Correctly detect initial character set for servers >= 4.1.0.  (Bug
     #3146)

   * Support placeholder for parameter metadata for server >= 4.1.2.
     (Bug #3146)

   * Added `gatherPerformanceMetrics' property, along with properties
     to control when/where this info gets logged (see docs for more
     info).

   * Fixed case when no parameters could cause a `NullPointerException'
     in `CallableStatement.setOutputParameters()'.

   * Enabled callable statement caching using `cacheCallableStmts'
     property.

   * Fixed sending of split packets for large queries, enabled nio
     ability to send large packets as well.

   * Added `.toString()' functionality to `ServerPreparedStatement',
     which should help if you're trying to debug a query that is a
     prepared statement (it shows SQL as the server would process).

   * Added `logSlowQueries' property, along with
     `slowQueriesThresholdMillis' property to control when a query
     should be considered `slow.'

   * Removed wrapping of exceptions in `MysqlIO.changeUser()'.

   * Fixed stored procedure parameter parsing info when size was
     specified for a parameter (for example, `char()', `varchar()').

   * `ServerPreparedStatements' weren't actually de-allocating
     server-side resources when `.close()' was called.

   * Fixed case when no output parameters specified for a stored
     procedure caused a bogus query to be issued to retrieve out
     parameters, leading to a syntax error from the server.


File: manual.info,  Node: cj-news-3-1-1,  Next: cj-news-3-1-0,  Prev: cj-news-3-1-2,  Up: cj-news-3-1-x

D.6.3.15 Changes in MySQL Connector/J 3.1.1 (14 February 2004 alpha)
....................................................................

*Bugs Fixed*

   * Use DocBook version of docs for shipped versions of drivers.  (Bug
     #2671)

   * `NULL' fields were not being encoded correctly in all cases in
     server-side prepared statements.  (Bug #2671)

   * Fixed rare buffer underflow when writing numbers into buffers for
     sending prepared statement execution requests.  (Bug #2671)

   * Fixed `ConnectionProperties' that weren't properly exposed through
     accessors, cleaned up `ConnectionProperties' code.  (Bug #2623)

   * Class-cast exception when using scrolling result sets and
     server-side prepared statements.  (Bug #2623)

   * Merged unbuffered input code from 3.0.  (Bug #2623)

   * Enabled streaming of result sets from server-side prepared
     statements.  (Bug #2606)

   * Server-side prepared statements were not returning data type *Note
     `YEAR': year. correctly.  (Bug #2606)

   * Fixed charset conversion issue in `getTables()'.  (Bug #2502)

   * Implemented multiple result sets returned from a statement or
     stored procedure.  (Bug #2502)

   * Implemented `Connection.prepareCall()', and `DatabaseMetaData'.
     `getProcedures()' and `getProcedureColumns()'.  (Bug #2359)

   * Merged prepared statement caching, and `.getMetaData()' support
     from 3.0 branch.  (Bug #2359)

   * Fixed off-by-1900 error in some cases for years in
     `TimeUtil.fastDate'/`TimeCreate()' when unpacking results from
     server-side prepared statements.  (Bug #2359)

   * Reset `long binary' parameters in `ServerPreparedStatement' when
     `clearParameters()' is called, by sending `COM_RESET_STMT' to the
     server.  (Bug #2359)

   * `NULL' values for numeric types in binary encoded result sets
     causing `NullPointerExceptions'.  (Bug #2359)

   * Display where/why a connection was implicitly closed (to aid
     debugging).  (Bug #1673)

   * `DatabaseMetaData.getColumns()' is not returning correct column
     ordinal info for non-`'%'' column name patterns.  (Bug #1673)

   * Fixed `NullPointerException' in
     `ServerPreparedStatement.setTimestamp()', as well as year and
     month discrepencies in `ServerPreparedStatement.setTimestamp()',
     `setDate()'.  (Bug #1673)

   * Added ability to have multiple database/JVM targets for compliance
     and regression/unit tests in `build.xml'.  (Bug #1673)

   * Fixed sending of queries larger than 16M.  (Bug #1673)

   * Merged fix of data type mapping from MySQL type *Note `FLOAT':
     numeric-types. to `java.sql.Types.REAL' from 3.0 branch.  (Bug
     #1673)

   * Fixed NPE and year/month bad conversions when accessing some
     datetime functionality in `ServerPreparedStatements' and their
     resultant result sets.  (Bug #1673)

   * Added named and indexed input/output parameter support to
     `CallableStatement'. MySQL-5.0.x or newer.  (Bug #1673)

   * `CommunicationsException' implemented, that tries to determine why
     communications was lost with a server, and displays possible
     reasons when `.getMessage()' is called.  (Bug #1673)

   * Detect collation of column for `RSMD.isCaseSensitive()'.  (Bug
     #1673)

   * Optimized `Buffer.readLenByteArray()' to return shared empty byte
     array when length is 0.

   * Fix support for table aliases when checking for all primary keys
     in `UpdatableResultSet'.

   * Unpack `unknown' data types from server prepared statements as
     `Strings'.

   * Implemented `Statement.getWarnings()' for MySQL-4.1 and newer
     (using *Note `SHOW WARNINGS': show-warnings.).

   * Ensure that warnings are cleared before executing queries on
     prepared statements, as-per JDBC spec (now that we support
     warnings).

   * Correctly initialize datasource properties from JNDI Refs,
     including explicitly specified URLs.

   * Implemented long data (Blobs, Clobs, InputStreams, Readers) for
     server prepared statements.

   * Deal with 0-length tokens in `EscapeProcessor' (caused by callable
     statement escape syntax).

   * `DatabaseMetaData' now reports `supportsStoredProcedures()' for
     MySQL versions >= 5.0.0

   * Support for *Note `mysql_change_user()': mysql-change-user.  See
     the `changeUser()' method in `com.mysql.jdbc.Connection'.

   * Removed `useFastDates' connection property.

   * Support for NIO. Use `useNIO=true' on platforms that support NIO.

   * Check for closed connection on delete/update/insert row operations
     in `UpdatableResultSet'.

   * Support for transaction savepoints (MySQL >= 4.0.14 or 4.1.1).

   * Support `old' `profileSql' capitalization in
     `ConnectionProperties'. This property is deprecated, you should use
     `profileSQL' if possible.

   * Fixed character encoding issues when converting bytes to ASCII
     when MySQL doesn't provide the character set, and the JVM is set
     to a multi-byte encoding (usually affecting retrieval of numeric
     values).

   * Centralized setting of result set type and concurrency.

   * Fixed bug with `UpdatableResultSets' not using client-side
     prepared statements.

   * Default result set type changed to `TYPE_FORWARD_ONLY' (JDBC
     compliance).

   * Fixed `IllegalAccessError' to `Calendar.getTimeInMillis()' in
     `DateTimeValue' (for JDK < 1.4).

   * Allow contents of `PreparedStatement.setBlob()' to be retained
     between calls to `.execute*()'.

   * Fixed stack overflow in `Connection.prepareCall()' (bad merge).

   * Refactored how connection properties are set and exposed as
     `DriverPropertyInfo' as well as `Connection' and `DataSource'
     properties.

   * Reduced number of methods called in average query to be more
     efficient.

   * Prepared `Statements' will be re-prepared on auto-reconnect. Any
     errors encountered are postponed until first attempt to re-execute
     the re-prepared statement.


File: manual.info,  Node: cj-news-3-1-0,  Prev: cj-news-3-1-1,  Up: cj-news-3-1-x

D.6.3.16 Changes in MySQL Connector/J 3.1.0 (18 February 2003 alpha)
....................................................................

*Bugs Fixed*

   * Added `useServerPrepStmts' property (default `false'). The driver
     will use server-side prepared statements when the server version
     supports them (4.1 and newer) when this property is set to `true'.
     It is currently set to `false' by default until all bind/fetch
     functionality has been implemented. Currently only DML prepared
     statements are implemented for 4.1 server-side prepared statements.

   * Added `requireSSL' property.

   * Track open `Statements', close all when `Connection.close()' is
     called (JDBC compliance).


File: manual.info,  Node: cj-news-3-0-x,  Next: cj-news-2-0-x,  Prev: cj-news-3-1-x,  Up: cj-news

D.6.4 Changes in MySQL Connector/J 3.0.x
----------------------------------------

* Menu:

* cj-news-3-0-17::               Changes in MySQL Connector/J 3.0.17 (23 June 2005)
* cj-news-3-0-16::               Changes in MySQL Connector/J 3.0.16 (15 November 2004)
* cj-news-3-0-15::               Changes in MySQL Connector/J 3.0.15 (04 September 2004)
* cj-news-3-0-14::               Changes in MySQL Connector/J 3.0.14 (28 May 2004)
* cj-news-3-0-13::               Changes in MySQL Connector/J 3.0.13 (27 May 2004)
* cj-news-3-0-12::               Changes in MySQL Connector/J 3.0.12 (18 May 2004)
* cj-news-3-0-11::               Changes in MySQL Connector/J 3.0.11 (19 February 2004)
* cj-news-3-0-10::               Changes in MySQL Connector/J 3.0.10 (13 January 2004)
* cj-news-3-0-9::                Changes in MySQL Connector/J 3.0.9 (07 October 2003)
* cj-news-3-0-8::                Changes in MySQL Connector/J 3.0.8 (23 May 2003)
* cj-news-3-0-7::                Changes in MySQL Connector/J 3.0.7 (08 April 2003)
* cj-news-3-0-6::                Changes in MySQL Connector/J 3.0.6 (18 February 2003)
* cj-news-3-0-5::                Changes in MySQL Connector/J 3.0.5 (22 January 2003)
* cj-news-3-0-4::                Changes in MySQL Connector/J 3.0.4 (06 January 2003)
* cj-news-3-0-3::                Changes in MySQL Connector/J 3.0.3 (17 December 2002)
* cj-news-3-0-2::                Changes in MySQL Connector/J 3.0.2 (08 November 2002)
* cj-news-3-0-1::                Changes in MySQL Connector/J 3.0.1 (21 September 2002)
* cj-news-3-0-0::                Changes in MySQL Connector/J 3.0.0 (31 July 2002)


File: manual.info,  Node: cj-news-3-0-17,  Next: cj-news-3-0-16,  Prev: cj-news-3-0-x,  Up: cj-news-3-0-x

D.6.4.1 Changes in MySQL Connector/J 3.0.17 (23 June 2005)
..........................................................

*Bugs Fixed*

   * Workaround for server Bug #9098: Default values of `CURRENT_*' for
     *Note `DATE': datetime, *Note `TIME': time, *Note `DATETIME':
     datetime, and *Note `TIMESTAMP': datetime. columns can't be
     distinguished from `string' values, so
     `UpdatableResultSet.moveToInsertRow()' generates bad SQL for
     inserting default values.  (Bug #8812)

   * `NON_UNIQUE' column from `DBMD.getIndexInfo()' returned inverted
     value.  (Bug #8812)

   * `EUCKR' charset is sent as `SET NAMES euc_kr' which MySQL-4.1 and
     newer doesn't understand.  (Bug #8629)

   * Added support for the `EUC_JP_Solaris' character encoding, which
     maps to a MySQL encoding of `eucjpms' (backported from 3.1
     branch). This only works on servers that support `eucjpms', namely
     5.0.3 or later.  (Bug #8629)

   * Use hex escapes for `PreparedStatement.setBytes()' for double-byte
     charsets including `aliases' `Windows-31J', `CP934', `MS932'.
     (Bug #8629)

   * `DatabaseMetaData.supportsSelectForUpdate()' returns correct value
     based on server version.  (Bug #8629)

   * Which requires hex escaping of binary data when using multi-byte
     charsets with prepared statements.  (Bug #8064)

   * Fixed duplicated code in `configureClientCharset()' that prevented
     `useOldUTF8Behavior=true' from working properly.  (Bug #7952)

   * Backported SQLState codes mapping from Connector/J 3.1, enable
     with `useSqlStateCodes=true' as a connection property, it defaults
     to `false' in this release, so that we don't break legacy
     applications (it defaults to `true' starting with Connector/J 3.1).
     (Bug #7686)

   * Timestamp key column data needed `_binary' stripped for
     `UpdatableResultSet.refreshRow()'.  (Bug #7686)

   * `MS932', `SHIFT_JIS', and `Windows_31J' not recognized as aliases
     for `sjis'.  (Bug #7607)

   * Handle streaming result sets with more than 2 billion rows
     properly by fixing wraparound of row number counter.  (Bug #7601)

   * `PreparedStatement.fixDecimalExponent()' adding extra `+', making
     number unparseable by MySQL server.  (Bug #7601)

   * Escape sequence {fn convert(..., type)} now supports ODBC-style
     types that are prepended by `SQL_'.  (Bug #7601)

   * Statements created from a pooled connection were returning
     physical connection instead of logical connection when
     `getConnection()' was called.  (Bug #7316)

   * Support new protocol type `MYSQL_TYPE_VARCHAR'.  (Bug #7081)

   * Added `useOldUTF8Behavior'' configuration property, which causes
     JDBC driver to act like it did with MySQL-4.0.x and earlier when
     the character encoding is `utf-8' when connected to MySQL-4.1 or
     newer.  (Bug #7081)

   * `DatabaseMetaData.getIndexInfo()' ignored `unique' parameter.
     (Bug #7081)

   * `PreparedStatement.fixDecimalExponent()' adding extra `+', making
     number unparseable by MySQL server.  (Bug #7061)

   * `PreparedStatements' don't encode Big5 (and other multi-byte)
     character sets correctly in static SQL strings.  (Bug #7033)

   * Connections starting up failed-over (due to down master) never
     retry master.  (Bug #6966)

   * Adding `CP943' to aliases for `sjis'.  (Bug #6549, Bug #7607)

   * `Timestamp'/`Time' conversion goes in the wrong `direction' when
     `useTimeZone=true' and server time zone differs from client time
     zone.  (Bug #5874)


File: manual.info,  Node: cj-news-3-0-16,  Next: cj-news-3-0-15,  Prev: cj-news-3-0-17,  Up: cj-news-3-0-x

D.6.4.2 Changes in MySQL Connector/J 3.0.16 (15 November 2004)
..............................................................

*Bugs Fixed*

   * Made `TINYINT(1)' -> *Note `BIT': numeric-types./`Boolean'
     conversion configurable using `tinyInt1isBit' property (default
     `true' to be JDBC compliant out of the box).  (Bug #5664)

   * Off-by-one bug in `Buffer.readString(STRING)'.  (Bug #5664)

   * `ResultSet.updateByte()' when on insert row throws
     `ArrayOutOfBoundsException'.  (Bug #5664)

   * Fixed regression where `useUnbufferedInput' was defaulting to
     `false'.  (Bug #5664)

   * `ResultSet.getTimestamp()' on a column with *Note `TIME': time. in
     it fails.  (Bug #5664)

   * Fixed `DatabaseMetaData.getTypes()' returning incorrect (this is,
     nonnegative) scale for the *Note `NUMERIC': numeric-types. type.
     (Bug #5664)

   * Only set `character_set_results' during connection establishment
     if server version >= 4.1.1.  (Bug #5664)

   * Fixed `ResultSetMetaData.isReadOnly()' to detect nonwritable
     columns when connected to MySQL-4.1 or newer, based on existence
     of `original' table and column names.

   * Re-issue character set configuration commands when re-using pooled
     connections or `Connection.changeUser()' when connected to
     MySQL-4.1 or newer.


File: manual.info,  Node: cj-news-3-0-15,  Next: cj-news-3-0-14,  Prev: cj-news-3-0-16,  Up: cj-news-3-0-x

D.6.4.3 Changes in MySQL Connector/J 3.0.15 (04 September 2004)
...............................................................

*Bugs Fixed*

   * `ResultSet.getMetaData()' should not return incorrectly
     initialized metadata if the result set has been closed, but should
     instead throw an `SQLException'. Also fixed for `getRow()' and
     `getWarnings()' and traversal methods by calling `checkClosed()'
     before operating on instance-level fields that are nullified during
     `.close()'.  (Bug #5069)

   * Use `_binary' introducer for `PreparedStatement.setBytes()' and
     `set*Stream()' when connected to MySQL-4.1.x or newer to avoid
     misinterpretation during character conversion.  (Bug #5069)

   * Parse new time zone variables from 4.1.x servers.  (Bug #5069)

   * `ResultSet' should release `Field[]' instance in `.close()'.  (Bug
     #5022)

   * `RSMD.getPrecision()' returning 0 for nonnumeric types (should
     return max length in chars for nonbinary types, max length in
     bytes for binary types). This fix also fixes mapping of
     `RSMD.getColumnType()' and `RSMD.getColumnTypeName()' for the
     *Note `BLOB': blob. types based on the length sent from the server
     (the server doesn't distinguish between *Note `TINYBLOB': blob,
     *Note `BLOB': blob, *Note `MEDIUMBLOB': blob. or *Note `LONGBLOB':
     blob. at the network protocol level).  (Bug #4880)

   * `Production' is now `GA' (General Availability) in naming scheme
     of distributions.  (Bug #4860, Bug #4138)

   * `DBMD.getColumns()' returns incorrect JDBC type for unsigned
     columns. This affects type mappings for all numeric types in the
     `RSMD.getColumnType()' and `RSMD.getColumnTypeNames()' methods as
     well, to ensure that `like' types from `DBMD.getColumns()' match
     up with what `RSMD.getColumnType()' and `getColumnTypeNames()'
     return.  (Bug #4860, Bug #4138)

   * Calling `.close()' twice on a `PooledConnection' causes NPE.  (Bug
     #4808)

   * *Note `DOUBLE': numeric-types. mapped twice in
     `DBMD.getTypeInfo()'.  (Bug #4742)

   * Added FLOSS license exemption.  (Bug #4742)

   * Removed redundant calls to `checkRowPos()' in `ResultSet'.  (Bug
     #4334)

   * Failover for `autoReconnect' not using port numbers for any hosts,
     and not retrying all hosts.

     *Warning*:

     This required a change to the `SocketFactory' `connect()' method
     signature, which is now `public Socket connect(String host, int
     portNumber, Properties props)'; therefore, any third-party socket
     factories will have to be changed to support this signature.

     (Bug #4334)

   * Logical connections created by `MysqlConnectionPoolDataSource'
     will now issue a `rollback()' when they are closed and sent back
     to the pool. If your application server/connection pool already
     does this for you, you can set the `rollbackOnPooledClose'
     property to `false' to avoid the overhead of an extra `rollback()'.
     (Bug #4334)

   * `StringUtils.escapeEasternUnicodeByteStream' was still broken for
     GBK.  (Bug #4010)


File: manual.info,  Node: cj-news-3-0-14,  Next: cj-news-3-0-13,  Prev: cj-news-3-0-15,  Up: cj-news-3-0-x

D.6.4.4 Changes in MySQL Connector/J 3.0.14 (28 May 2004)
.........................................................

*Bugs Fixed*

   * Fixed URL parsing error.


File: manual.info,  Node: cj-news-3-0-13,  Next: cj-news-3-0-12,  Prev: cj-news-3-0-14,  Up: cj-news-3-0-x

D.6.4.5 Changes in MySQL Connector/J 3.0.13 (27 May 2004)
.........................................................

*Bugs Fixed*

   * `No Database Selected' when using `MysqlConnectionPoolDataSource'.
     (Bug #3920)

   * `PreparedStatement.getGeneratedKeys()' method returns only 1
     result for batched insertions.  (Bug #3873)

   * Using a `MySQLDatasource' without server name fails.  (Bug #3848)


File: manual.info,  Node: cj-news-3-0-12,  Next: cj-news-3-0-11,  Prev: cj-news-3-0-13,  Up: cj-news-3-0-x

D.6.4.6 Changes in MySQL Connector/J 3.0.12 (18 May 2004)
.........................................................

*Bugs Fixed*

   * Inconsistent reporting of data type. The server still doesn't
     return all types for *BLOBs *TEXT correctly, so the driver won't
     return those correctly.  (Bug #3570)

   * `UpdatableResultSet' not picking up default values for
     `moveToInsertRow()'.  (Bug #3557)

   * Not specifying database in URL caused `MalformedURL' exception.
     (Bug #3554)

   * Auto-convert MySQL encoding names to Java encoding names if used
     for `characterEncoding' property.  (Bug #3554)

   * Use `junit.textui.TestRunner' for all unit tests (to enable them
     to be run from the command line outside of Ant or Eclipse).  (Bug
     #3554)

   * Added encoding names that are recognized on some JVMs to fix case
     where they were reverse-mapped to MySQL encoding names incorrectly.
     (Bug #3554)

   * Made `StringRegressionTest' 4.1-unicode aware.  (Bug #3520)

   * Fixed regression in `PreparedStatement.setString()' and eastern
     character encodings.  (Bug #3520)

   * `DBMD.getSQLStateType()' returns incorrect value.  (Bug #3520)

   * Renamed `StringUtils.escapeSJISByteStream()' to more appropriate
     `escapeEasternUnicodeByteStream()'.  (Bug #3511)

   * `StringUtils.escapeSJISByteStream()' not covering all eastern
     double-byte charsets correctly.  (Bug #3511)

   * Return creating statement for `ResultSets' created by
     `getGeneratedKeys()'.  (Bug #2957)

   * Use `SET character_set_results' during initialization to enable
     any charset to be returned to the driver for result sets.  (Bug
     #2670)

   * Don't truncate `BLOB' or `CLOB' values when using `setBytes()' and
     `setBinary/CharacterStream()'.  (Bug #2670)

   * Dynamically configure character set mappings for field-level
     character sets on MySQL-4.1.0 and newer using *Note `SHOW
     COLLATION': show-collation. when connecting.  (Bug #2670)

   * Map `binary' character set to `US-ASCII' to support *Note
     `DATETIME': datetime. charset recognition for servers >= 4.1.2.
     (Bug #2670)

   * Use `charsetnr' returned during connect to encode queries before
     issuing `SET NAMES' on MySQL >= 4.1.0.  (Bug #2670)

   * Add helper methods to `ResultSetMetaData'
     (`getColumnCharacterEncoding()' and `getColumnCharacterSet()') to
     permit end users to see what charset the driver thinks it should
     be using for the column.  (Bug #2670)

   * Only set `character_set_results' for MySQL >= 4.1.0.  (Bug #2670)

   * Allow `url' parameter for `MysqlDataSource' and
     `MysqlConnectionPool' `DataSource' so that passing of other
     properties is possible from inside appservers.

   * Don't escape SJIS/GBK/BIG5 when using MySQL-4.1 or newer.

   * Backport documentation tooling from 3.1 branch.

   * Added `failOverReadOnly' property, to enable the user to configure
     the state of the connection (read-only/writable) when failed over.

   * Add unsigned attribute to `DatabaseMetaData.getColumns()' output
     in the `TYPE_NAME' column.

   * Allow `java.util.Date' to be sent in as parameter to
     `PreparedStatement.setObject()', converting it to a `Timestamp' to
     maintain full precision. .  (Bug #103)

   * Map duplicate key and foreign key errors to SQLState of `23000'.

   * Backported `change user' and `reset server state' functionality
     from 3.1 branch, to enable clients of
     `MysqlConnectionPoolDataSource' to reset server state on
     `getConnection()' on a pooled connection.


File: manual.info,  Node: cj-news-3-0-11,  Next: cj-news-3-0-10,  Prev: cj-news-3-0-12,  Up: cj-news-3-0-x

D.6.4.7 Changes in MySQL Connector/J 3.0.11 (19 February 2004)
..............................................................

*Bugs Fixed*

   * Return `java.lang.Double' for *Note `FLOAT': numeric-types. type
     from `ResultSetMetaData.getColumnClassName()'.  (Bug #2855)

   * Return `[B' instead of `java.lang.Object' for *Note `BINARY':
     binary-varbinary, *Note `VARBINARY': binary-varbinary. and
     `LONGVARBINARY' types from
     `ResultSetMetaData.getColumnClassName()' (JDBC compliance).  (Bug
     #2855)

   * Issue connection events on all instances created from a
     `ConnectionPoolDataSource'.  (Bug #2855)

   * Return `java.lang.Integer' for *Note `TINYINT': numeric-types. and
     *Note `SMALLINT': numeric-types. types from
     `ResultSetMetaData.getColumnClassName()'.  (Bug #2852)

   * Added `useUnbufferedInput' parameter, and now use it by default
     (due to JVM issue
     `http://developer.java.sun.com/developer/bugParade/bugs/4401235.html')
     (Bug #2578)

   * Fixed failover always going to last host in list.  (Bug #2578)

   * Detect `on'/`off' or `1', `2', `3' form of `lower_case_table_names'
     value on server.  (Bug #2578)

   * `AutoReconnect' time was growing faster than exponentially.  (Bug
     #2447)

   * Trigger a `SET NAMES utf8' when encoding is forced to `utf8' _or_
     `utf-8' using the `characterEncoding' property. Previously, only
     the Java-style encoding name of `utf-8' would trigger this.


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D.6.4.8 Changes in MySQL Connector/J 3.0.10 (13 January 2004)
.............................................................

*Bugs Fixed*

   * Enable caching of the parsing stage of prepared statements using
     the `cachePrepStmts', `prepStmtCacheSize', and
     `prepStmtCacheSqlLimit' properties (disabled by default).  (Bug
     #2006)

   * Fixed security exception when used in Applets (applets can't read
     the system property `file.encoding' which is needed for *Note
     `LOAD DATA LOCAL INFILE': load-data.).  (Bug #2006)

   * Speed up parsing of `PreparedStatements', try to use one-pass
     whenever possible.  (Bug #2006)

   * Fixed exception `Unknown character set 'danish'' on connect with
     JDK-1.4.0 (Bug #2006)

   * Fixed mappings in SQLError to report deadlocks with SQLStates of
     `41000'.  (Bug #2006)

   * Removed static synchronization bottleneck from instance factory
     method of `SingleByteCharsetConverter'.  (Bug #2006)

   * Removed static synchronization bottleneck from
     `PreparedStatement.setTimestamp()'.  (Bug #2006)

   * `ResultSet.findColumn()' should use first matching column name
     when there are duplicate column names in *Note `SELECT': select.
     query (JDBC-compliance).  (Bug #2006)

   * `maxRows' property would affect internal statements, so check it
     for all statement creation internal to the driver, and set to 0
     when it is not.  (Bug #2006)

   * Use constants for SQLStates.  (Bug #2006)

   * Map charset `ko18_ru' to `ko18r' when connected to MySQL-4.1.0 or
     newer.  (Bug #2006)

   * Ensure that `Buffer.writeString()' saves room for the `\0'.  (Bug
     #2006)

   * `ArrayIndexOutOfBounds' when parameter number == number of
     parameters + 1.  (Bug #1958)

   * Connection property `maxRows' not honored.  (Bug #1933)

   * Statements being created too many times in
     `DBMD.extractForeignKeyFromCreateTable()'.  (Bug #1925)

   * Support escape sequence {fn convert ... }.  (Bug #1914)

   * Implement `ResultSet.updateClob()'.  (Bug #1913)

   * Autoreconnect code didn't set catalog upon reconnect if it had
     been changed.  (Bug #1913)

   * `ResultSet.getObject()' on *Note `TINYINT': numeric-types. and
     *Note `SMALLINT': numeric-types. columns should return Java type
     `Integer'.  (Bug #1913)

   * Added more descriptive error message `Server Configuration Denies
     Access to DataSource', as well as retrieval of message from server.
     (Bug #1913)

   * `ResultSetMetaData.isCaseSensitive()' returned wrong value for
     *Note `CHAR': char./*Note `VARCHAR': char.  columns.  (Bug #1913)

   * Added `alwaysClearStream' connection property, which causes the
     driver to always empty any remaining data on the input stream
     before each query.  (Bug #1913)

   * `DatabaseMetaData.getSystemFunction()' returning bad function
     `VResultsSion'.  (Bug #1775)

   * Foreign Keys column sequence is not consistent in
     `DatabaseMetaData.getImported/Exported/CrossReference()'.  (Bug
     #1731)

   * Fix for `ArrayIndexOutOfBounds' exception when using
     `Statement.setMaxRows()'.  (Bug #1695)

   * Subsequent call to `ResultSet.updateFoo()' causes NPE if result
     set is not updatable.  (Bug #1630)

   * Fix for 4.1.1-style authentication with no password.  (Bug #1630)

   * Cross-database updatable result sets are not checked for
     updatability correctly.  (Bug #1592)

   * `DatabaseMetaData.getColumns()' should return `Types.LONGVARCHAR'
     for MySQL *Note `LONGTEXT': blob. type.  (Bug #1592)

   * Fixed regression of `Statement.getGeneratedKeys()' and *Note
     `REPLACE': replace. statements.  (Bug #1576)

   * Barge blobs and split packets not being read correctly.  (Bug
     #1576)

   * Backported fix for aliased tables and `UpdatableResultSets' in
     `checkUpdatability()' method from 3.1 branch.  (Bug #1534)

   * `Friendlier' exception message for `PacketTooLargeException'.
     (Bug #1534)

   * Don't count quoted IDs when inside a 'string' in
     `PreparedStatement' parsing.  (Bug #1511)


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D.6.4.9 Changes in MySQL Connector/J 3.0.9 (07 October 2003)
............................................................

*Bugs Fixed*

   * `ResultSet.get/setString' mashing char 127.  (Bug #1247)

   * Added property to `clobber' streaming results, by setting the
     `clobberStreamingResults' property to `true' (the default is
     `false'). This will cause a `streaming' `ResultSet' to be
     automatically closed, and any outstanding data still streaming
     from the server to be discarded if another query is executed
     before all the data has been read from the server.  (Bug #1247)

   * Added `com.mysql.jdbc.util.BaseBugReport' to help creation of
     testcases for bug reports.  (Bug #1247)

   * Backported authentication changes for 4.1.1 and newer from 3.1
     branch.  (Bug #1247)

   * Made `databaseName', `portNumber', and `serverName' optional
     parameters for `MysqlDataSourceFactory'.  (Bug #1246)

   * Optimized `CLOB.setChracterStream()'.  (Bug #1131)

   * Fixed `CLOB.truncate()'.  (Bug #1130)

   * Fixed deadlock issue with `Statement.setMaxRows()'.  (Bug #1099)

   * `DatabaseMetaData.getColumns()' getting confused about the keyword
     `set' in character columns.  (Bug #1099)

   * Clip +/- INF (to smallest and largest representative values for
     the type in MySQL) and NaN (to 0) for `setDouble'/`setFloat()', and
     issue a warning on the statement when the server does not support
     +/- INF or NaN.  (Bug #884)

   * Don't fire connection closed events when closing pooled
     connections, or on `PooledConnection.getConnection()' with already
     open connections.  (Bug #884)

   * Double-escaping of `'\'' when charset is SJIS or GBK and `'\''
     appears in nonescaped input.  (Bug #879)

   * When emptying input stream of unused rows for `streaming' result
     sets, have the current thread `yield()' every 100 rows to not
     monopolize CPU time.  (Bug #879)

   * Issue exception on `ResultSet.getXXX()' on empty result set
     (wasn't caught in some cases).  (Bug #848)

   * Don't hide messages from exceptions thrown in I/O layers.  (Bug
     #848)

   * Fixed regression in large split-packet handling.  (Bug #848)

   * Better diagnostic error messages in exceptions for `streaming'
     result sets.  (Bug #848)

   * Don't change timestamp TZ twice if `useTimezone==true'.  (Bug #774)

   * Don't wrap `SQLExceptions' in `RowDataDynamic'.  (Bug #688)

   * Don't try and reset isolation level on reconnect if MySQL doesn't
     support them.  (Bug #688)

   * The `insertRow' in an `UpdatableResultSet' is now loaded with the
     default column values when `moveToInsertRow()' is called.  (Bug
     #688)

   * `DatabaseMetaData.getColumns()' wasn't returning `NULL' for
     default values that are specified as `NULL'.  (Bug #688)

   * Change default statement type/concurrency to `TYPE_FORWARD_ONLY'
     and `CONCUR_READ_ONLY' (spec compliance).  (Bug #688)

   * Fix `UpdatableResultSet' to return values for `getXXX()' when on
     insert row.  (Bug #675)

   * Support `InnoDB' constraint names when extracting foreign key
     information in `DatabaseMetaData' (implementing ideas from
     Parwinder Sekhon).  (Bug #664, Bug #517)

   * Backported 4.1 protocol changes from 3.1 branch (server-side SQL
     states, new field information, larger client capability flags,
     connect-with-database, and so forth).  (Bug #664, Bug #517)

   * `refreshRow' didn't work when primary key values contained values
     that needed to be escaped (they ended up being doubly escaped).
     (Bug #661)

   * Fixed `ResultSet.previous()' behavior to move current position to
     before result set when on first row of result set.  (Bug #496)

   * Fixed `Statement' and `PreparedStatement' issuing bogus queries
     when `setMaxRows()' had been used and a `LIMIT' clause was present
     in the query.  (Bug #496)

   * Faster date handling code in `ResultSet' and `PreparedStatement'
     (no longer uses `Date' methods that synchronize on static
     calendars).

   * Fixed test for end of buffer in `Buffer.readString()'.


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D.6.4.10 Changes in MySQL Connector/J 3.0.8 (23 May 2003)
.........................................................

*Bugs Fixed*

   * Fixed SJIS encoding bug, thanks to Naoto Sato.  (Bug #378)

   * Fix problem detecting server character set in some cases.  (Bug
     #378)

   * Allow multiple calls to `Statement.close()'.  (Bug #378)

   * Return correct number of generated keys when using *Note
     `REPLACE': replace. statements.  (Bug #378)

   * Unicode character 0xFFFF in a string would cause the driver to
     throw an `ArrayOutOfBoundsException'. .  (Bug #378)

   * Fix row data decoding error when using _very_ large packets.  (Bug
     #378)

   * Optimized row data decoding.  (Bug #378)

   * Issue exception when operating on an already closed prepared
     statement.  (Bug #378)

   * Optimized usage of `EscapeProcessor'.  (Bug #378)

   * Use JVM charset with file names and `LOAD DATA [LOCAL] INFILE'.

   * Fix infinite loop with `Connection.cleanup()'.

   * Changed Ant target `compile-core' to `compile-driver', and made
     testsuite compilation a separate target.

   * Fixed result set not getting set for `Statement.executeUpdate()',
     which affected `getGeneratedKeys()' and `getUpdateCount()' in some
     cases.

   * Return list of generated keys when using multi-value `INSERTS' with
     `Statement.getGeneratedKeys()'.

   * Allow bogus URLs in `Driver.getPropertyInfo()'.


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D.6.4.11 Changes in MySQL Connector/J 3.0.7 (08 April 2003)
...........................................................

*Bugs Fixed*

   * Fixed charset issues with database metadata (charset was not
     getting set correctly).

   * You can now toggle profiling on/off using
     `Connection.setProfileSql(boolean)'.

   * 4.1 Column Metadata fixes.

   * Fixed `MysqlPooledConnection.close()' calling wrong event type.

   * Fixed `StringIndexOutOfBoundsException' in
     `PreparedStatement.setClob()'.

   * `IOExceptions' during a transaction now cause the `Connection' to
     be closed.

   * Remove synchronization from `Driver.connect()' and
     `Driver.acceptsUrl()'.

   * Fixed missing conversion for *Note `YEAR': year.  type in
     `ResultSetMetaData.getColumnTypeName()'.

   * Updatable `ResultSets' can now be created for aliased
     tables/columns when connected to MySQL-4.1 or newer.

   * Fixed *Note `LOAD DATA LOCAL INFILE': load-data. bug when file >
     `max_allowed_packet'.

   * Don't pick up indexes that start with `pri' as primary keys for
     `DBMD.getPrimaryKeys()'.

   * Ensure that packet size from `alignPacketSize()' does not exceed
     `max_allowed_packet' (JVM bug)

   * Don't reset `Connection.isReadOnly()' when autoReconnecting.

   * Fixed escaping of 0x5c (`'\'') character for GBK and Big5 charsets.

   * Fixed `ResultSet.getTimestamp()' when underlying field is of type
     *Note `DATE': datetime.

   * Throw `SQLExceptions' when trying to do operations on a forcefully
     closed `Connection' (that is, when a communication link failure
     occurs).


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D.6.4.12 Changes in MySQL Connector/J 3.0.6 (18 February 2003)
..............................................................

*Bugs Fixed*

   * Backported 4.1 charset field info changes from Connector/J 3.1.

   * Fixed `Statement.setMaxRows()' to stop sending `LIMIT' type
     queries when not needed (performance).

   * Fixed `DBMD.getTypeInfo()' and `DBMD.getColumns()' returning
     different value for precision in *Note `TEXT': blob. and *Note
     `BLOB': blob. types.

   * Fixed `SQLExceptions' getting swallowed on initial connect.

   * Fixed `ResultSetMetaData' to return `""' when catalog not known.
     Fixes `NullPointerExceptions' with Sun's `CachedRowSet'.

   * Allow ignoring of warning for `non transactional tables' during
     rollback (compliance/usability) by setting `ignoreNonTxTables'
     property to `true'.

   * Clean up `Statement' query/method mismatch tests (that is, *Note
     `INSERT': insert. not permitted with `.executeQuery()').

   * Fixed `ResultSetMetaData.isWritable()' to return correct value.

   * More checks added in `ResultSet' traversal method to catch when in
     closed state.

   * Implemented `Blob.setBytes()'. You still need to pass the
     resultant `Blob' back into an updatable `ResultSet' or
     `PreparedStatement' to persist the changes, because MySQL does not
     support `locators'.

   * Add `window' of different `NULL' sorting behavior to
     `DBMD.nullsAreSortedAtStart' (4.0.2 to 4.0.10, true; otherwise,
     no).


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D.6.4.13 Changes in MySQL Connector/J 3.0.5 (22 January 2003)
.............................................................

*Bugs Fixed*

   * Fixed `ResultSet.isBeforeFirst()' for empty result sets.

   * Added missing *Note `LONGTEXT': blob. type to `DBMD.getColumns()'.

   * Implemented an empty `TypeMap' for `Connection.getTypeMap()' so
     that some third-party apps work with MySQL (IBM WebSphere 5.0
     Connection pool).

   * Added update options for foreign key metadata.

   * Fixed `Buffer.fastSkipLenString()' causing `ArrayIndexOutOfBounds'
     exceptions with some queries when unpacking fields.

   * Quote table names in `DatabaseMetaData.getColumns()',
     `getPrimaryKeys()', `getIndexInfo()', `getBestRowIdentifier()'.

   * Retrieve `TX_ISOLATION' from database for
     `Connection.getTransactionIsolation()' when the MySQL version
     supports it, instead of an instance variable.

   * Greatly reduce memory required for `setBinaryStream()' in
     `PreparedStatements'.


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D.6.4.14 Changes in MySQL Connector/J 3.0.4 (06 January 2003)
.............................................................

*Bugs Fixed*

   * Streamlined character conversion and `byte[]' handling in
     `PreparedStatements' for `setByte()'.

   * Fixed `PreparedStatement.executeBatch()' parameter overwriting.

   * Added quoted identifiers to database names for
     `Connection.setCatalog'.

   * Added support for 4.0.8-style large packets.

   * Reduce memory footprint of `PreparedStatements' by sharing
     outbound packet with `MysqlIO'.

   * Added `strictUpdates' property to enable control of amount of
     checking for `correctness' of updatable result sets. Set this to
     `false' if you want faster updatable result sets and you know that
     you create them from *Note `SELECT': select.  statements on tables
     with primary keys and that you have selected all primary keys in
     your query.

   * Added support for quoted identifiers in `PreparedStatement' parser.


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D.6.4.15 Changes in MySQL Connector/J 3.0.3 (17 December 2002)
..............................................................

*Bugs Fixed*

   * Allow user to alter behavior of `Statement'/
     `PreparedStatement.executeBatch()' using `continueBatchOnError'
     property (defaults to `true').

   * More robust escape tokenizer: Recognize `--' comments, and permit
     nested escape sequences (see `testsuite.EscapeProcessingTest').

   * Fixed `Buffer.isLastDataPacket()' for 4.1 and newer servers.

   * `NamedPipeSocketFactory' now works (only intended for Windows),
     see `README' for instructions.

   * Changed `charsToByte' in `SingleByteCharConverter' to be nonstatic.

   * Use nonaliased table/column names and database names to fully
     qualify tables and columns in `UpdatableResultSet' (requires
     MySQL-4.1 or newer).

   * `LOAD DATA LOCAL INFILE ...' now works, if your server is
     configured to permit it. Can be turned off with the
     `allowLoadLocalInfile' property (see the `README').

   * Implemented `Connection.nativeSQL()'.

   * Fixed `ResultSetMetaData.getColumnTypeName()' returning *Note
     `BLOB': blob. for *Note `TEXT': blob. and *Note `TEXT': blob. for
     *Note `BLOB': blob. types.

   * Fixed charset handling in `Fields.java'.

   * Because of above, implemented
     `ResultSetMetaData.isAutoIncrement()' to use
     `Field.isAutoIncrement()'.

   * Substitute `'?'' for unknown character conversions in single-byte
     character sets instead of `'\0''.

   * Added `CLIENT_LONG_FLAG' to be able to get more column flags
     (`isAutoIncrement()' being the most important).

   * Honor `lower_case_table_names' when enabled in the server when
     doing table name comparisons in `DatabaseMetaData' methods.

   * `DBMD.getImported/ExportedKeys()' now handles multiple foreign
     keys per table.

   * More robust implementation of updatable result sets. Checks that
     _all_ primary keys of the table have been selected.

   * Some MySQL-4.1 protocol support (extended field info from selects).

   * Check for connection closed in more `Connection' methods
     (`createStatement', `prepareStatement', `setTransactionIsolation',
     `setAutoCommit').

   * Fixed `ResultSetMetaData.getPrecision()' returning incorrect
     values for some floating-point types.

   * Changed `SingleByteCharConverter' to use lazy initialization of
     each converter.


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D.6.4.16 Changes in MySQL Connector/J 3.0.2 (08 November 2002)
..............................................................

*Bugs Fixed*

   * Implemented `Clob.setString()'.

   * Added `com.mysql.jdbc.MiniAdmin' class, which enables you to send
     `shutdown' command to MySQL server. This is intended to be used
     when `embedding' Java and MySQL server together in an end-user
     application.

   * Added SSL support. See `README' for information on how to use it.

   * All `DBMD' result set columns describing schemas now return `NULL'
     to be more compliant with the behavior of other JDBC drivers for
     other database systems (MySQL does not support schemas).

   * Use *Note `SHOW CREATE TABLE': show-create-table. when possible
     for determining foreign key information for `DatabaseMetaData'.
     Also enables cascade options for *Note `DELETE': delete.
     information to be returned.

   * Implemented `Clob.setCharacterStream()'.

   * Failover and `autoReconnect' work only when the connection is in
     an `autoCommit(false)' state, to stay transaction-safe.

   * Fixed `DBMD.supportsResultSetConcurrency()' so that it returns
     `true' for `ResultSet.TYPE_SCROLL_INSENSITIVE' and
     `ResultSet.CONCUR_READ_ONLY' or `ResultSet.CONCUR_UPDATABLE'.

   * Implemented `Clob.setAsciiStream()'.

   * Removed duplicate code from `UpdatableResultSet' (it can be
     inherited from `ResultSet', the extra code for each method to
     handle updatability I thought might someday be necessary has not
     been needed).

   * Fixed `UnsupportedEncodingException' thrown when `forcing' a
     character encoding using properties.

   * Fixed incorrect conversion in `ResultSet.getLong()'.

   * Implemented `ResultSet.updateBlob()'.

   * Removed some not-needed temporary object creation by smarter use
     of `Strings' in `EscapeProcessor', `Connection' and
     `DatabaseMetaData' classes.

   * Escape `0x5c' character in strings for the SJIS charset.

   * `PreparedStatement' now honors stream lengths in
     setBinary/Ascii/Character Stream() unless you set the connection
     property `useStreamLengthsInPrepStmts' to `false'.

   * Fixed issue with updatable result sets and `PreparedStatements'
     not working.

   * Fixed start position off-by-1 error in `Clob.getSubString()'.

   * Added `connectTimeout' parameter that enables users of JDK-1.4 and
     newer to specify a maximum time to wait to establish a connection.

   * Fixed various non-ASCII character encoding issues.

   * Fixed `ResultSet.isLast()' for empty result sets (should return
     `false').

   * Added driver property `useHostsInPrivileges'.  Defaults to `true'.
     Affects whether or not `@hostname' will be used in
     `DBMD.getColumn/TablePrivileges'.

   * Fixed `ResultSet.setFetchDirection(FETCH_UNKNOWN)'.

   * Added `queriesBeforeRetryMaster' property that specifies how many
     queries to issue when failed over before attempting to reconnect
     to the master (defaults to 50).

   * Fixed issue when calling `Statement.setFetchSize()' when using
     arbitrary values.

   * Properly restore connection properties when autoReconnecting or
     failing-over, including `autoCommit' state, and isolation level.

   * Implemented `Clob.truncate()'.


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D.6.4.17 Changes in MySQL Connector/J 3.0.1 (21 September 2002)
...............................................................

*Bugs Fixed*

   * Charsets now automatically detected. Optimized code for
     single-byte character set conversion.

   * Fixed `ResultSetMetaData.isSigned()' for *Note `TINYINT':
     numeric-types. and *Note `BIGINT': numeric-types.

   * Fixed `RowDataStatic.getAt()' off-by-one bug.

   * Fixed `ResultSet.getRow()' off-by-one bug.

   * Massive code clean-up to follow Java coding conventions (the time
     had come).

   * Implemented `ResultSet.getCharacterStream()'.

   * Added limited `Clob' functionality (`ResultSet.getClob()',
     `PreparedStatement.setClob()', `PreparedStatement.setObject(Clob)'.

   * `Connection.isClosed()' no longer `pings' the server.

   * `Connection.close()' issues `rollback()' when `getAutoCommit()' is
     `false'.

   * Added `socketTimeout' parameter to URL.

   * Added `LOCAL TEMPORARY' to table types in
     `DatabaseMetaData.getTableTypes()'.

   * Added `paranoid' parameter, which sanitizes error messages by
     removing `sensitive' information from them (such as host names,
     ports, or user names), as well as clearing `sensitive' data
     structures when possible.


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D.6.4.18 Changes in MySQL Connector/J 3.0.0 (31 July 2002)
..........................................................

*Bugs Fixed*

   * General source-code cleanup.

   * The driver now only works with JDK-1.2 or newer.

   * Fix and sort primary key names in `DBMetaData' (SF bugs 582086 and
     582086).

   * `ResultSet.getTimestamp()' now works for *Note `DATE': datetime.
     types (SF bug 559134).

   * Float types now reported as `java.sql.Types.FLOAT' (SF bug 579573).

   * Support for streaming (row-by-row) result sets (see `README')
     Thanks to Doron.

   * Testsuite now uses Junit (which you can get from
     `http://www.junit.org'.

   * JDBC Compliance: Passes all tests besides stored procedure tests.

   * `ResultSet.getDate/Time/Timestamp' now recognizes all forms of
     invalid values that have been set to all zeros by MySQL (SF bug
     586058).

   * Added multi-host failover support (see `README').

   * Repackaging: New driver name is `com.mysql.jdbc.Driver', old name
     still works, though (the driver is now provided by MySQL-AB).

   * Support for large packets (new addition to MySQL-4.0 protocol),
     see `README' for more information.

   * Better checking for closed connections in `Statement' and
     `PreparedStatement'.

   * Performance improvements in string handling and field metadata
     creation (lazily instantiated) contributed by Alex
     Twisleton-Wykeham-Fiennes.

   * JDBC-3.0 functionality including
     `Statement/PreparedStatement.getGeneratedKeys()' and
     `ResultSet.getURL()'.

   * Overall speed improvements using controlling transient object
     creation in `MysqlIO' class when reading packets.

   * *!!! LICENSE CHANGE !!!* The driver is now GPL. If you need
     non-GPL licenses, please contact me `<mark@mysql.com>'.

   * Performance enhancements: Driver is now 50-100% faster in most
     situations, and creates fewer temporary objects.


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D.6.5 Changes in MySQL Connector/J 2.0.x
----------------------------------------

* Menu:

* cj-news-2-0-14::               Changes in MySQL Connector/J 2.0.14 (16 May 2002)
* cj-news-2-0-13::               Changes in MySQL Connector/J 2.0.13 (24 April 2002)
* cj-news-2-0-12::               Changes in MySQL Connector/J 2.0.12 (07 April 2002)
* cj-news-2-0-11::               Changes in MySQL Connector/J 2.0.11 (27 January 2002)
* cj-news-2-0-10::               Changes in MySQL Connector/J 2.0.10 (24 January 2002)
* cj-news-2-0-9::                Changes in MySQL Connector/J 2.0.9 (13 January 2002)
* cj-news-2-0-8::                Changes in MySQL Connector/J 2.0.8 (25 November 2001)
* cj-news-2-0-7::                Changes in MySQL Connector/J 2.0.7 (24 October 2001)
* cj-news-2-0-6::                Changes in MySQL Connector/J 2.0.6 (16 June 2001)
* cj-news-2-0-5::                Changes in MySQL Connector/J 2.0.5 (13 June 2001)
* cj-news-2-0-3::                Changes in MySQL Connector/J 2.0.3 (03 December 2000)
* cj-news-2-0-1::                Changes in MySQL Connector/J 2.0.1 (06 April 2000)
* cj-news-2-0pre5::              Changes in MySQL Connector/J 2.0.0pre5 (21 February 2000)
* cj-news-2-0pre4::              Changes in MySQL Connector/J 2.0.0pre4 (10 January 2000)
* cj-news-2-0pre::               Changes in MySQL Connector/J 2.0.0pre (17 August 1999)


File: manual.info,  Node: cj-news-2-0-14,  Next: cj-news-2-0-13,  Prev: cj-news-2-0-x,  Up: cj-news-2-0-x

D.6.5.1 Changes in MySQL Connector/J 2.0.14 (16 May 2002)
.........................................................

*Bugs Fixed*

   * `ResultSet.getDouble()' now uses code built into JDK to be more
     precise (but slower).

   * Fixed typo for `relaxAutoCommit' parameter.

   * `LogicalHandle.isClosed()' calls through to physical connection.

   * Added SQL profiling (to `STDERR'). Set `profileSql=true' in your
     JDBC URL. See `README' for more information.

   * `PreparedStatement' now releases resources on `.close()'. (SF bug
     553268)

   * More code cleanup.

   * Quoted identifiers not used if server version does not support
     them. Also, if server started with `--ansi' or
     `--sql-mode=ANSI_QUOTES', ``"'' will be used as an identifier
     quote character, otherwise ``''' will be used.


File: manual.info,  Node: cj-news-2-0-13,  Next: cj-news-2-0-12,  Prev: cj-news-2-0-14,  Up: cj-news-2-0-x

D.6.5.2 Changes in MySQL Connector/J 2.0.13 (24 April 2002)
...........................................................

*Bugs Fixed*

   * Fixed unicode chars being read incorrectly. (SF bug 541088)

   * Faster blob escaping for `PrepStmt'.

   * Added `setURL()' to `MySQLXADataSource'. (SF bug 546019)

   * Added `set'/`getPortNumber()' to `DataSource(s)'. (SF bug 548167)

   * `PreparedStatement.toString()' fixed. (SF bug 534026)

   * More code cleanup.

   * Rudimentary version of `Statement.getGeneratedKeys()' from JDBC-3.0
     now implemented (you need to be using JDK-1.4 for this to work, I
     believe).

   * `DBMetaData.getIndexInfo()' - bad PAGES fixed.  (SF BUG 542201)

   * `ResultSetMetaData.getColumnClassName()' now implemented.


File: manual.info,  Node: cj-news-2-0-12,  Next: cj-news-2-0-11,  Prev: cj-news-2-0-13,  Up: cj-news-2-0-x

D.6.5.3 Changes in MySQL Connector/J 2.0.12 (07 April 2002)
...........................................................

*Bugs Fixed*

   * Fixed `testsuite.Traversal' `afterLast()' bug, thanks to Igor
     Lastric.

   * Added new types to `getTypeInfo()', fixed existing types thanks to
     Al Davis and Kid Kalanon.

   * Fixed time zone off-by-1-hour bug in `PreparedStatement' (538286,
     528785).

   * Added identifier quoting to all `DatabaseMetaData' methods that
     need them (should fix 518108).

   * Added support for *Note `BIT': numeric-types. types (51870) to
     `PreparedStatement'.

   * `ResultSet.insertRow()' should now detect auto_increment fields in
     most cases and use that value in the new row. This detection will
     not work in multi-valued keys, however, due to the fact that the
     MySQL protocol does not return this information.

   * Relaxed synchronization in all classes, should fix 520615 and
     520393.

   * `DataSources' - fixed `setUrl' bug (511614, 525565), wrong
     datasource class name (532816, 528767).

   * Added support for *Note `YEAR': year. type (533556).

   * Fixes for `ResultSet' updatability in `PreparedStatement'.

   * `ResultSet': Fixed updatability (values being set to `null' if not
     updated).

   * Added `getTable/ColumnPrivileges()' to DBMD (fixes 484502).

   * Added `getIdleFor()' method to `Connection' and
     `MysqlLogicalHandle'.

   * `ResultSet.refreshRow()' implemented.

   * Fixed `getRow()' bug (527165) in `ResultSet'.

   * General code cleanup.


File: manual.info,  Node: cj-news-2-0-11,  Next: cj-news-2-0-10,  Prev: cj-news-2-0-12,  Up: cj-news-2-0-x

D.6.5.4 Changes in MySQL Connector/J 2.0.11 (27 January 2002)
.............................................................

*Bugs Fixed*

   * Full synchronization of `Statement.java'.

   * Fixed missing `DELETE_RULE' value in
     `DBMD.getImported/ExportedKeys()' and `getCrossReference()'.

   * More changes to fix `Unexpected end of input stream' errors when
     reading *Note `BLOB': blob. values. This should be the last fix.


File: manual.info,  Node: cj-news-2-0-10,  Next: cj-news-2-0-9,  Prev: cj-news-2-0-11,  Up: cj-news-2-0-x

D.6.5.5 Changes in MySQL Connector/J 2.0.10 (24 January 2002)
.............................................................

*Bugs Fixed*

   * Fixed null-pointer-exceptions when using
     `MysqlConnectionPoolDataSource' with Websphere 4 (bug 505839).

   * Fixed spurious `Unexpected end of input stream' errors in
     `MysqlIO' (bug 507456).


File: manual.info,  Node: cj-news-2-0-9,  Next: cj-news-2-0-8,  Prev: cj-news-2-0-10,  Up: cj-news-2-0-x

D.6.5.6 Changes in MySQL Connector/J 2.0.9 (13 January 2002)
............................................................

*Bugs Fixed*

   * Fixed extra memory allocation in `MysqlIO.readPacket()' (bug
     488663).

   * Added detection of network connection being closed when reading
     packets (thanks to Todd Lizambri).

   * Fixed casting bug in `PreparedStatement' (bug 488663).

   * `DataSource' implementations moved to
     `org.gjt.mm.mysql.jdbc2.optional' package, and (initial)
     implementations of `PooledConnectionDataSource' and `XADataSource'
     are in place (thanks to Todd Wolff for the implementation and
     testing of `PooledConnectionDataSource' with IBM WebSphere 4).

   * Fixed quoting error with escape processor (bug 486265).

   * Removed concatenation support from driver (the `||' operator), as
     older versions of VisualAge seem to be the only thing that use it,
     and it conflicts with the logical `||' operator. You will need to
     start *Note `mysqld': mysqld. with the `--ansi' flag to use the
     `||' operator as concatenation (bug 491680).

   * `Ant' build was corrupting included `jar' files, fixed (bug
     487669).

   * Report batch update support through `DatabaseMetaData' (bug
     495101).

   * Implementation of `DatabaseMetaData.getExported/ImportedKeys()'
     and `getCrossReference()'.

   * Fixed off-by-one-hour error in `PreparedStatement.setTimestamp()'
     (bug 491577).

   * Full synchronization on methods modifying instance and
     class-shared references, driver should be entirely thread-safe now
     (please let me know if you have problems).


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D.6.5.7 Changes in MySQL Connector/J 2.0.8 (25 November 2001)
.............................................................

*Bugs Fixed*

   * `XADataSource'/`ConnectionPoolDataSource' code (experimental)

   * `DatabaseMetaData.getPrimaryKeys()' and `getBestRowIdentifier()'
     are now more robust in identifying primary keys (matches
     regardless of case or abbreviation/full spelling of `Primary Key'
     in `Key_type' column).

   * Batch updates now supported (thanks to some inspiration from
     Daniel Rall).

   * `PreparedStatement.setAnyNumericType()' now handles positive
     exponents correctly (adds `+' so MySQL can understand it).


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D.6.5.8 Changes in MySQL Connector/J 2.0.7 (24 October 2001)
............................................................

*Bugs Fixed*

   * Character sets read from database if `useUnicode=true' and
     `characterEncoding' is not set. (thanks to Dmitry Vereshchagin)

   * Initial transaction isolation level read from database (if
     available). (thanks to Dmitry Vereshchagin)

   * Fixed `PreparedStatement' generating SQL that would end up with
     syntax errors for some queries.

   * `PreparedStatement.setCharacterStream()' now implemented

   * Capitalize type names when `capitalizeTypeNames=true' is passed in
     URL or properties (for WebObjects. (thanks to Anjo Krank)

   * `ResultSet.getBlob()' now returns `null' if column value was
     `null'.

   * Fixed `ResultSetMetaData.getPrecision()' returning one less than
     actual on newer versions of MySQL.

   * Fixed dangling socket problem when in high availability
     (`autoReconnect=true') mode, and finalizer for `Connection' will
     close any dangling sockets on GC.

   * Fixed time zone issue in `PreparedStatement.setTimestamp()'.
     (thanks to Erik Olofsson)

   * PreparedStatement.setDouble() now uses full-precision doubles
     (reverting a fix made earlier to truncate them).

   * Fixed `DatabaseMetaData.supportsTransactions()', and
     `supportsTransactionIsolationLevel()' and `getTypeInfo()'
     `SQL_DATETIME_SUB' and `SQL_DATA_TYPE' fields not being readable.

   * Updatable result sets now correctly handle `NULL' values in fields.

   * PreparedStatement.setBoolean() will use 1/0 for values if your
     MySQL version is 3.21.23 or higher.

   * Fixed `ResultSet.isAfterLast()' always returning `false'.


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D.6.5.9 Changes in MySQL Connector/J 2.0.6 (16 June 2001)
.........................................................

*Bugs Fixed*

   * Fixed `PreparedStatement' parameter checking.

   * Fixed case-sensitive column names in `ResultSet.java'.


File: manual.info,  Node: cj-news-2-0-5,  Next: cj-news-2-0-3,  Prev: cj-news-2-0-6,  Up: cj-news-2-0-x

D.6.5.10 Changes in MySQL Connector/J 2.0.5 (13 June 2001)
..........................................................

*Bugs Fixed*

   * `ResultSet.insertRow()' works now, even if not all columns are set
     (they will be set to `NULL').

   * Added `Byte' to `PreparedStatement.setObject()'.

   * Fixed data parsing of *Note `TIMESTAMP': datetime.  values with
     2-digit years.

   * Added `ISOLATION' level support to `Connection.setIsolationLevel()'

   * `DataBaseMetaData.getCrossReference()' no longer `ArrayIndexOOB'.

   * `ResultSet.getBoolean()' now recognizes `-1' as `true'.

   * `ResultSet' has +/-Inf/inf support.

   * `getObject()' on `ResultSet' correctly does *Note `TINYINT':
     numeric-types.->`Byte' and *Note `SMALLINT':
     numeric-types.->`Short'.

   * Fixed `ResultSetMetaData.getColumnTypeName' for *Note `TEXT':
     blob./*Note `BLOB': blob.

   * Fixed `ArrayIndexOutOfBounds' when sending large *Note `BLOB':
     blob. queries. (Max size packet was not being set)

   * Fixed NPE on `PreparedStatement.executeUpdate()' when all columns
     have not been set.

   * Fixed `ResultSet.getBlob()' `ArrayIndex' out-of-bounds.


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D.6.5.11 Changes in MySQL Connector/J 2.0.3 (03 December 2000)
..............................................................

*Bugs Fixed*

   * Fixed composite key problem with updatable result sets.

   * Faster ASCII string operations.

   * Fixed off-by-one error in `java.sql.Blob' implementation code.

   * Fixed incorrect detection of `MAX_ALLOWED_PACKET', so sending
     large blobs should work now.

   * Added detection of -/+INF for doubles.

   * Added `ultraDevHack' URL parameter, set to `true' to enable
     (broken) Macromedia UltraDev to use the driver.

   * Implemented `getBigDecimal()' without scale component for JDBC2.


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D.6.5.12 Changes in MySQL Connector/J 2.0.1 (06 April 2000)
...........................................................

*Bugs Fixed*

   * Columns that are of type *Note `TEXT': blob. now return as
     `Strings' when you use `getObject()'.

   * Cleaned up exception handling when driver connects.

   * Fixed `RSMD.isWritable()' returning wrong value. Thanks to Moritz
     Maass.

   * `DatabaseMetaData.getPrimaryKeys()' now works correctly with
     respect to `key_seq'. Thanks to Brian Slesinsky.

   * Fixed many JDBC-2.0 traversal, positioning bugs, especially with
     respect to empty result sets. Thanks to Ron Smits, Nick Brook,
     Cessar Garcia and Carlos Martinez.

   * No escape processing is done on `PreparedStatements' anymore per
     JDBC spec.

   * Fixed some issues with updatability support in `ResultSet' when
     using multiple primary keys.


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D.6.5.13 Changes in MySQL Connector/J 2.0.0pre5 (21 February 2000)
..................................................................

   * Fixed Bad Handshake problem.


File: manual.info,  Node: cj-news-2-0pre4,  Next: cj-news-2-0pre,  Prev: cj-news-2-0pre5,  Up: cj-news-2-0-x

D.6.5.14 Changes in MySQL Connector/J 2.0.0pre4 (10 January 2000)
.................................................................

   * Fixes to ResultSet for insertRow() - Thanks to Cesar Garcia

   * Fix to Driver to recognize JDBC-2.0 by loading a JDBC-2.0 class,
     instead of relying on JDK version numbers. Thanks to John Baker.

   * Fixed ResultSet to return correct row numbers

   * Statement.getUpdateCount() now returns rows matched, instead of
     rows actually updated, which is more SQL-92 like.

10-29-99

   * Statement/PreparedStatement.getMoreResults() bug fixed.  Thanks to
     Noel J. Bergman.

   * Added Short as a type to PreparedStatement.setObject().  Thanks to
     Jeff Crowder

   * Driver now automagically configures maximum/preferred packet sizes
     by querying server.

   * Autoreconnect code uses fast ping command if server supports it.

   * Fixed various bugs with respect to packet sizing when reading from
     the server and when alloc'ing to write to the server.


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D.6.5.15 Changes in MySQL Connector/J 2.0.0pre (17 August 1999)
...............................................................

   * Now compiles under JDK-1.2. The driver supports both JDK-1.1 and
     JDK-1.2 at the same time through a core set of classes.  The
     driver will load the appropriate interface classes at runtime by
     figuring out which JVM version you are using.

   * Fixes for result sets with all nulls in the first row.  (Pointed
     out by Tim Endres)

   * Fixes to column numbers in SQLExceptions in ResultSet (Thanks to
     Blas Rodriguez Somoza)

   * The database no longer needs to specified to connect.  (Thanks to
     Christian Motschke)


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D.6.6 Changes in MySQL Connector/J 1.2.x and lower
--------------------------------------------------

* Menu:

* cj-news-1-2b::                 Changes in MySQL Connector/J 1.2b (04 July 1999)
* cj-news-1-2a::                 Changes in MySQL Connector/J 1.2a (14 April 1999)
* cj-news-1-1i::                 Changes in MySQL Connector/J 1.1i (24 March 1999)
* cj-news-1-1h::                 Changes in MySQL Connector/J 1.1h (08 March 1999)
* cj-news-1-1g::                 Changes in MySQL Connector/J 1.1g (19 February 1999)
* cj-news-1-1f::                 Changes in MySQL Connector/J 1.1f (31 December 1998)
* cj-news-1-1b::                 Changes in MySQL Connector/J 1.1b (03 November 1998)
* cj-news-1-1::                  Changes in MySQL Connector/J 1.1 (02 September 1998)
* cj-news-1-0::                  Changes in MySQL Connector/J 1.0 (24 August 1998)
* cj-news-0-9d::                 Changes in MySQL Connector/J 0.9d (04 August 1998)
* cj-news-0-9::                  Changes in MySQL Connector/J 0.9 (28 July 1998)
* cj-news-0-8::                  Changes in MySQL Connector/J 0.8 (06 July 1998)
* cj-news-0-7::                  Changes in MySQL Connector/J 0.7 (01 July 1998)
* cj-news-0-6::                  Changes in MySQL Connector/J 0.6 (21 May 1998)


File: manual.info,  Node: cj-news-1-2b,  Next: cj-news-1-2a,  Prev: cj-news-1-2-x,  Up: cj-news-1-2-x

D.6.6.1 Changes in MySQL Connector/J 1.2b (04 July 1999)
........................................................

   * Better Documentation (in progress), in doc/mm.doc/book1.html

   * DBMD now permits null for a column name pattern (not in spec),
     which it changes to '%'.

   * DBMD now has correct types/lengths for getXXX().

   * ResultSet.getDate(), getTime(), and getTimestamp() fixes.
     (contributed by Alan Wilken)

   * EscapeProcessor now handles \{ \} and { or } inside quotation
     marks correctly. (thanks to Alik for some ideas on how to fix it)

   * Fixes to properties handling in Connection. (contributed by Juho
     Tikkala)

   * ResultSet.getObject() now returns null for NULL columns in the
     table, rather than bombing out. (thanks to Ben Grosman)

   * ResultSet.getObject() now returns Strings for types from MySQL
     that it doesn't know about. (Suggested by Chris Perdue)

   * Removed DataInput/Output streams, not needed, 1/2 number of method
     calls per IO operation.

   * Use default character encoding if one is not specified. This is a
     work-around for broken JVMs, because according to spec, EVERY JVM
     must support "ISO8859_1", but they do not.

   * Fixed Connection to use the platform character encoding instead of
     "ISO8859_1" if one isn't explicitly set. This fixes problems
     people were having loading the character- converter classes that
     didn't always exist (JVM bug).  (thanks to Fritz Elfert for
     pointing out this problem)

   * Changed MysqlIO to re-use packets where possible to reduce memory
     usage.

   * Fixed escape-processor bugs pertaining to {} inside quotation
     marks.


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D.6.6.2 Changes in MySQL Connector/J 1.2a (14 April 1999)
.........................................................

   * Fixed character-set support for non-Javasoft JVMs (thanks to many
     people for pointing it out)

   * Fixed ResultSet.getBoolean() to recognize 'y' & 'n' as well as '1'
     & '0' as boolean flags. (thanks to Tim Pizey)

   * Fixed ResultSet.getTimestamp() to give better performance.
     (thanks to Richard Swift)

   * Fixed getByte() for numeric types. (thanks to Ray Bellis)

   * Fixed DatabaseMetaData.getTypeInfo() for DATE type. (thanks to
     Paul Johnston)

   * Fixed EscapeProcessor for "fn" calls. (thanks to Piyush Shah at
     locomotive.org)

   * Fixed EscapeProcessor to not do extraneous work if there are no
     escape codes. (thanks to Ryan Gustafson)

   * Fixed Driver to parse URLs of the form "jdbc:mysql://host:port"
     (thanks to Richard Lobb)


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D.6.6.3 Changes in MySQL Connector/J 1.1i (24 March 1999)
.........................................................

   * Fixed Timestamps for PreparedStatements

   * Fixed null pointer exceptions in RSMD and RS

   * Re-compiled with jikes for valid class files (thanks ms!)


File: manual.info,  Node: cj-news-1-1h,  Next: cj-news-1-1g,  Prev: cj-news-1-1i,  Up: cj-news-1-2-x

D.6.6.4 Changes in MySQL Connector/J 1.1h (08 March 1999)
.........................................................

   * Fixed escape processor to deal with unmatched { and } (thanks to
     Craig Coles)

   * Fixed escape processor to create more portable (between DATETIME
     and TIMESTAMP types) representations so that it will work with
     BETWEEN clauses. (thanks to Craig Longman)

   * MysqlIO.quit() now closes the socket connection. Before, after
     many failed connections some OS's would run out of file
     descriptors. (thanks to Michael Brinkman)

   * Fixed NullPointerException in Driver.getPropertyInfo.  (thanks to
     Dave Potts)

   * Fixes to MysqlDefs to allow all *text fields to be retrieved as
     Strings. (thanks to Chris at Leverage)

   * Fixed setDouble in PreparedStatement for large numbers to avoid
     sending scientific notation to the database. (thanks to J.S.
     Ferguson)

   * Fixed getScale() and getPrecision() in RSMD. (contrib'd by James
     Klicman)

   * Fixed getObject() when field was DECIMAL or NUMERIC (thanks to
     Bert Hobbs)

   * DBMD.getTables() bombed when passed a null table-name pattern.
     Fixed. (thanks to Richard Lobb)

   * Added check for "client not authorized" errors during connect.
     (thanks to Hannes Wallnoefer)


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D.6.6.5 Changes in MySQL Connector/J 1.1g (19 February 1999)
............................................................

   * Result set rows are now byte arrays. Blobs and Unicode work
     bidirectonally now. The useUnicode and encoding options are
     implemented now.

   * Fixes to PreparedStatement to send binary set by setXXXStream to
     be sent untouched to the MySQL server.

   * Fixes to getDriverPropertyInfo().


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D.6.6.6 Changes in MySQL Connector/J 1.1f (31 December 1998)
............................................................

   * Changed all ResultSet fields to Strings, this should allow Unicode
     to work, but your JVM must be able to convert between the
     character sets. This should also make reading data from the server
     be a bit quicker, because there is now no conversion from
     StringBuffer to String.

   * Changed PreparedStatement.streamToString() to be more efficient
     (code from Uwe Schaefer).

   * URL parsing is more robust (throws SQL exceptions on errors rather
     than NullPointerExceptions)

   * PreparedStatement now can convert Strings to Time/Date values
     using setObject() (code from Robert Currey).

   * IO no longer hangs in Buffer.readInt(), that bug was introduced in
     1.1d when changing to all byte-arrays for result sets. (Pointed
     out by Samo Login)


File: manual.info,  Node: cj-news-1-1b,  Next: cj-news-1-1,  Prev: cj-news-1-1f,  Up: cj-news-1-2-x

D.6.6.7 Changes in MySQL Connector/J 1.1b (03 November 1998)
............................................................

   * Fixes to DatabaseMetaData to allow both IBM VA and J-Builder to
     work. Let me know how it goes. (thanks to Jac Kersing)

   * Fix to ResultSet.getBoolean() for NULL strings (thanks to Barry
     Lagerweij)

   * Beginning of code cleanup, and formatting. Getting ready to branch
     this off to a parallel JDBC-2.0 source tree.

   * Added "final" modifier to critical sections in MysqlIO and Buffer
     to allow compiler to inline methods for speed.

9-29-98

   * If object references passed to setXXX() in PreparedStatement are
     null, setNull() is automatically called for you. (Thanks for the
     suggestion goes to Erik Ostrom)

   * setObject() in PreparedStatement will now attempt to write a
     serialized representation of the object to the database for
     objects of Types.OTHER and objects of unknown type.

   * Util now has a static method readObject() which given a ResultSet
     and a column index will re-instantiate an object serialized in the
     above manner.


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D.6.6.8 Changes in MySQL Connector/J 1.1 (02 September 1998)
............................................................

   * Got rid of "ugly hack" in MysqlIO.nextRow(). Rather than catch an
     exception, Buffer.isLastDataPacket() was fixed.

   * Connection.getCatalog() and Connection.setCatalog() should work
     now.

   * Statement.setMaxRows() works, as well as setting by property
     maxRows. Statement.setMaxRows() overrides maxRows set using
     properties or url parameters.

   * Automatic re-connection is available. Because it has to "ping" the
     database before each query, it is turned off by default. To use
     it, pass in "autoReconnect=true" in the connection URL. You may
     also change the number of reconnect tries, and the initial timeout
     value using "maxReconnects=n" (default 3) and "initialTimeout=n"
     (seconds, default 2) parameters. The timeout is an exponential
     backoff type of timeout; for example, if you have initial timeout
     of 2 seconds, and maxReconnects of 3, then the driver will timeout
     2 seconds, 4 seconds, then 16 seconds between each re-connection
     attempt.


File: manual.info,  Node: cj-news-1-0,  Next: cj-news-0-9d,  Prev: cj-news-1-1,  Up: cj-news-1-2-x

D.6.6.9 Changes in MySQL Connector/J 1.0 (24 August 1998)
.........................................................

   * Fixed handling of blob data in Buffer.java

   * Fixed bug with authentication packet being sized too small.

   * The JDBC Driver is now under the LGPL

8-14-98

   * Fixed Buffer.readLenString() to correctly read data for BLOBS.

   * Fixed PreparedStatement.stringToStream to correctly read data for
     BLOBS.

   * Fixed PreparedStatement.setDate() to not add a day. (above fixes
     thanks to Vincent Partington)

   * Added URL parameter parsing (?user=... and so forth).


File: manual.info,  Node: cj-news-0-9d,  Next: cj-news-0-9,  Prev: cj-news-1-0,  Up: cj-news-1-2-x

D.6.6.10 Changes in MySQL Connector/J 0.9d (04 August 1998)
...........................................................

   * Big news! New package name. Tim Endres from ICE Engineering is
     starting a new source tree for GNU GPL'd Java software.  He's
     graciously given me the org.gjt.mm package directory to use, so
     now the driver is in the org.gjt.mm.mysql package scheme. I'm
     "legal" now. Look for more information on Tim's project soon.

   * Now using dynamically sized packets to reduce memory usage when
     sending commands to the DB.

   * Small fixes to getTypeInfo() for parameters, and so forth.

   * DatabaseMetaData is now fully implemented. Let me know if these
     drivers work with the various IDEs out there. I've heard that
     they're working with JBuilder right now.

   * Added JavaDoc documentation to the package.

   * Package now available in .zip or .tar.gz.


File: manual.info,  Node: cj-news-0-9,  Next: cj-news-0-8,  Prev: cj-news-0-9d,  Up: cj-news-1-2-x

D.6.6.11 Changes in MySQL Connector/J 0.9 (28 July 1998)
........................................................

   * Implemented getTypeInfo(). Connection.rollback() now throws an
     SQLException per the JDBC spec.

   * Added PreparedStatement that supports all JDBC API methods for
     PreparedStatement including InputStreams. Please check this out
     and let me know if anything is broken.

   * Fixed a bug in ResultSet that would break some queries that only
     returned 1 row.

   * Fixed bugs in DatabaseMetaData.getTables(),
     DatabaseMetaData.getColumns() and DatabaseMetaData.getCatalogs().

   * Added functionality to Statement that enables executeUpdate() to
     store values for IDs that are automatically generated for
     AUTO_INCREMENT fields.  Basically, after an executeUpdate(), look
     at the SQLWarnings for warnings like "LAST_INSERTED_ID = 'some
     number', COMMAND = 'your SQL query'". If you are using
     AUTO_INCREMENT fields in your tables and are executing a lot of
     executeUpdate()s on one Statement, be sure to clearWarnings()
     every so often to save memory.


File: manual.info,  Node: cj-news-0-8,  Next: cj-news-0-7,  Prev: cj-news-0-9,  Up: cj-news-1-2-x

D.6.6.12 Changes in MySQL Connector/J 0.8 (06 July 1998)
........................................................

   * Split MysqlIO and Buffer to separate classes. Some ClassLoaders
     gave an IllegalAccess error for some fields in those two classes.
     Now mm.mysql works in applets and all classloaders. Thanks to Joe
     Ennis <jce@mail.boone.com> for pointing out the problem and
     working on a fix with me.


File: manual.info,  Node: cj-news-0-7,  Next: cj-news-0-6,  Prev: cj-news-0-8,  Up: cj-news-1-2-x

D.6.6.13 Changes in MySQL Connector/J 0.7 (01 July 1998)
........................................................

   * Fixed DatabaseMetadata problems in getColumns() and bug in switch
     statement in the Field constructor. Thanks to Costin Manolache
     <costin@tdiinc.com> for pointing these out.


File: manual.info,  Node: cj-news-0-6,  Prev: cj-news-0-7,  Up: cj-news-1-2-x

D.6.6.14 Changes in MySQL Connector/J 0.6 (21 May 1998)
.......................................................

   * Incorporated efficiency changes from Richard Swift
     <Richard.Swift@kanatek.ca> in `MysqlIO.java' and `ResultSet.java':

   * We're now 15% faster than gwe's driver.

   * Started working on `DatabaseMetaData'.

   * The following methods are implemented:

        * `getTables()'

        * `getTableTypes()'

        * `getColumns()'

        * `getCatalogs()'


File: manual.info,  Node: news-connector-mxj,  Next: mysql-proxy-news,  Prev: cj-news,  Up: news

D.7 MySQL Connector/MXJ Change History
======================================

* Menu:

* news-connector-mxj-5-0-12::    Changes in MySQL Connector/MXJ 5.0.12 (07 July 2011)
* news-connector-mxj-5-0-11::    Changes in MySQL Connector/MXJ 5.0.11 (24 November 2009)
* news-connector-mxj-5-0-10::    Changes in MySQL Connector/MXJ 5.0.10 (Not released)
* news-connector-mxj-5-0-9::     Changes in MySQL Connector/MXJ 5.0.9 (19 August 2008)
* news-connector-mxj-5-0-8::     Changes in MySQL Connector/MXJ 5.0.8 (06 August 2007)
* news-connector-mxj-5-0-7::     Changes in MySQL Connector/MXJ 5.0.7 (27 May 2007)
* news-connector-mxj-5-0-6::     Changes in MySQL Connector/MXJ 5.0.6 (04 May 2007)
* news-connector-mxj-5-0-5::     Changes in MySQL Connector/MXJ 5.0.5 (14 March 2007)
* news-connector-mxj-5-0-4::     Changes in MySQL Connector/MXJ 5.0.4 (28 January 2007)
* news-connector-mxj-5-0-3::     Changes in MySQL Connector/MXJ 5.0.3 (24 June 2006)
* news-connector-mxj-5-0-2::     Changes in MySQL Connector/MXJ 5.0.2 (15 June 2006)
* news-connector-mxj-5-0-1::     Changes in MySQL Connector/MXJ 5.0.1 (Not released)
* news-connector-mxj-5-0-0::     Changes in MySQL Connector/MXJ 5.0.0 (09 December 2005)


File: manual.info,  Node: news-connector-mxj-5-0-12,  Next: news-connector-mxj-5-0-11,  Prev: news-connector-mxj,  Up: news-connector-mxj

D.7.1 Changes in MySQL Connector/MXJ 5.0.12 (07 July 2011)
----------------------------------------------------------

*Functionality Added or Changed*

   * *Incompatible Change*: Connector/MXJ now contains MySQL 5.5.9, not
     MySQL 5.1.

   * These platform mappings were added:

        * Windows_Vista-amd64=Win-x86

        * Windows_2003-amd64=Win-x86

        * Windows_2000-amd64=Win-x86

        * FreeBSD-i386=FreeBSD-x86


File: manual.info,  Node: news-connector-mxj-5-0-11,  Next: news-connector-mxj-5-0-10,  Prev: news-connector-mxj-5-0-12,  Up: news-connector-mxj

D.7.2 Changes in MySQL Connector/MXJ 5.0.11 (24 November 2009)
--------------------------------------------------------------

*Functionality Added or Changed*

   * The embedded MySQL binaries have been updated to MySQL 5.1.40 for
     GPL releases and MySQL 5.1.40 for Commercial releases.

   * The contents of the directory used for bootstrapping the MySQL
     databases is now configurable by using the `windows-share-dir-jar'
     property. You should supply the name of a jar containing the files
     you want to use.

   * The embedded Aspect/J class has been removed.

   * The default timeout for the kill delay within the embedded test
     suite has been increased from 10 to 30 seconds.

*Bugs Fixed*

   * On startup Connector/MXJ generated an exception on Windows 7:

          Exception in thread "Thread-3" java.util.MissingResourceException?: Resource
          `5-0-51a/Windows_7-x86/mysqld-nt.exe' not found
          at com.mysql.management.util.Streams.getResourceAsStream(Streams.java:133)
          at com.mysql.management.util.Streams.getResourceAsStream(Streams.java:107)
          at com.mysql.management.util.Streams$1.inner(Streams.java:149) at
          com.mysql.management.util.Exceptions$VoidBlock?.exec(Exceptions.java:128)
          at com.mysql.management.util.Streams.createFileFromResource(Streams.java:162)
          at com.mysql.management.MysqldResource?.makeMysqld(MysqldResource?.java:533)
          at com.mysql.management.MysqldResource?.deployFiles(MysqldResource?.java:518)
          at com.mysql.management.MysqldResource?.exec(MysqldResource?.java:495)
          at com.mysql.management.MysqldResource?.start(MysqldResource?.java:216)
          at com.mysql.management.MysqldResource?.start(MysqldResource?.java:166)

     The default `platform-map.properties' file, which maps platforms
     to the supplied binary bundles, has been updated with additional
     platforms, including Windows 7, Windows Server 2008, `amd64' and
     `sparcv9' for Solaris, and Mac OS X 64-bit.  (Bug #48298)


File: manual.info,  Node: news-connector-mxj-5-0-10,  Next: news-connector-mxj-5-0-9,  Prev: news-connector-mxj-5-0-11,  Up: news-connector-mxj

D.7.3 Changes in MySQL Connector/MXJ 5.0.10 (Not released)
----------------------------------------------------------

This was an internal only release.

*Functionality Added or Changed*

   * The embedded MySQL has been updated to the MySQL 5.1 series. The
     embedded MySQL binaries have been updated to MySQL 5.1.33 for GPL
     releases and MySQL 5.1.34 for Commercial releases.

   * The MySQL binary for Windows targets has been updated to be
     configurable through the `windows-mysqld-command' property. This
     is to handle the move in MySQL 5.1.33 from *Note `mysqld-nt.exe':
     mysqld. to *Note `mysqld.exe': mysqld. The default value is *Note
     `mysqld.exe': mysqld.


File: manual.info,  Node: news-connector-mxj-5-0-9,  Next: news-connector-mxj-5-0-8,  Prev: news-connector-mxj-5-0-10,  Up: news-connector-mxj

D.7.4 Changes in MySQL Connector/MXJ 5.0.9 (19 August 2008)
-----------------------------------------------------------

*Functionality Added or Changed*

   * The port used in the `ConnectorMXJUrlTestExample' and
     `ConnectorMXJObjectTestExample' port is no longer hard coded.
     Instead, the code uses the `x-mxj_test_port' property a default
     value of `3336'

   * The utility used to kill MySQL on Windows (`kill.exe') has been
     configured to be loaded from the `kill.exe' property, instead of
     being hard-coded. The corresponding timeout, `KILL_DELAY' has also
     been moved to the properties file and defaults to 5 minutes.

   * The embedded MySQL binaries have been updated to MySQL 5.0.51a for
     GPL releases and MySQL 5.0.54 for Commercial releases.

   * The timeout for kill operations in the embedded test suite has
     been set to a default of 10 seconds.


File: manual.info,  Node: news-connector-mxj-5-0-8,  Next: news-connector-mxj-5-0-7,  Prev: news-connector-mxj-5-0-9,  Up: news-connector-mxj

D.7.5 Changes in MySQL Connector/MXJ 5.0.8 (06 August 2007)
-----------------------------------------------------------

*Functionality Added or Changed*

   * The embedded documentation has been updated so that it now points
     to the main MySQL documentation pages in the MySQL reference
     manual.

   * The embedded MySQL binaries have been updated to MySQL 5.0.45 for
     GPL releases and MySQL 5.0.46 for Commercial releases.


File: manual.info,  Node: news-connector-mxj-5-0-7,  Next: news-connector-mxj-5-0-6,  Prev: news-connector-mxj-5-0-8,  Up: news-connector-mxj

D.7.6 Changes in MySQL Connector/MXJ 5.0.7 (27 May 2007)
--------------------------------------------------------

*Functionality Added or Changed*

   * Updated the jar file name to be consistent with the Connector/J
     jar file name. Files are now formatted as
     `mysql-connector-mxj-MXJ-VERSION'.

   * The `ConnectorMXJUrlTestExample' and
     `ConnectorMXJObjectTestExammple' have been updated to include an
     example of initializing the user/password and creating an initial
     database. The `InitializePasswordExample' example class has now
     been removed.

   * The `PatchedStandardSocketFactory' class has been removed, because
     it fixed an issue in Connector/J that was corrected in Connector/J
     5.0.6.

   * The embedded MySQL binaries have been updated to MySQL 5.0.41 for
     GPL releases and MySQL 5.0.42 for Commercial releases.

*Bugs Fixed*

   * Added a null-check to deal with class loaders where
     `getClassLoader()' returns null.


File: manual.info,  Node: news-connector-mxj-5-0-6,  Next: news-connector-mxj-5-0-5,  Prev: news-connector-mxj-5-0-7,  Up: news-connector-mxj

D.7.7 Changes in MySQL Connector/MXJ 5.0.6 (04 May 2007)
--------------------------------------------------------

*Functionality Added or Changed*

   * Updated internal jar file names to include version information and
     be more consistent with Connector/J jar naming. For example,
     `connector-mxj.jar' is now
     `mysql-connector-mxj-${mxj-version}.jar'.

   * Updated commercial license files.

   * Added copyright notices to some classes which were missing them.

   * Added InitializeUser and QueryUtil classes to support new feature.

   * Added new tests for initial-user & expanded some existing tests.

   * ConnectorMXJUrlTestExample and ConnectorMXJObjectTestExample now
     demonstrate the initialization of user/password and creating the
     initial database (rather than using "test").

   * Added new connection property `initialize-user' which, if set to
     `true' will remove the default, un-passworded anonymous and root
     users, and create the user/password from the connection url.

   * Removed obsolete field `SimpleMysqldDynamicMBean.lastInvocation'.

   * Clarified code in `DefaultsMap.entrySet()'.

   * Removed obsolete `PatchedStandardSocketFactory' java file.

   * Added `main(String[])' to
     `com/mysql/management/AllTestsSuite.java'.

   * Errors reading `portFile' are now reported using
     `stacktrace(err)', previously `System.err' was used.

   * `portFile' now contains a new-line to be consistent with `pidFile'.

   * Fixed where versionString.trim() was ignored.

   * Removed references to File.deleteOnExit, a warning is printed
     instead.

*Bugs Fixed*

   * Changed tests to shutdown mysqld prior to deleting files.

   * Fixed port file to always be written to datadir.

   * Added os.name-os.arch to resource directory mapping properties
     file.

   * Swapped out commercial binaries for v5.0.40.

   * Delete `portFile' on shutdown.

   * Moved `platform-map.properties' into `db-files.jar'.

   * Clarified the startup max wait numbers.

   * Updated `build.xml' in preperation for next beta build.

   * Removed `use-default-architecture' property replaced.

   * Added null-check to deal with C/MXJ being loaded by the bootstrap
     classloaders with JVMs for which `getClassLoader()' returns null.

   * Added robustness around reading portfile.

   * Removed `PatchedStandardSocketFactory' (fixed in Connector/J
     5.0.6).

   * Refactored duplication from tests and examples to QueryUtil.

   * Removed obsolete InitializePasswordExample


File: manual.info,  Node: news-connector-mxj-5-0-5,  Next: news-connector-mxj-5-0-4,  Prev: news-connector-mxj-5-0-6,  Up: news-connector-mxj

D.7.8 Changes in MySQL Connector/MXJ 5.0.5 (14 March 2007)
----------------------------------------------------------

*Bugs Fixed*

   * Moved `MysqldFactory' to main package.

   * Reformatting: Added newlines some files which did not end in them.

   * Swapped out commercial binaries for v5.0.36.

   * Found and removed dynamic linking in mysql_kill; updated solution.

   * Changed protected constructor of `SimpleMysqldDynamicMBean' from
     taking a `MysqldResource' to taking a `MysqldFactory', to lay
     groundwork for addressing BUG discovered by Andrew Rubinger. See:
     143046#msg-143046MySQL Forums (Actual testing with JBoss, and
     filing a bug, is still required.)

   * `build.xml': `usage' now slightly more verbose; some reformatting.

   * Now incorporates Reggie Bernett's `SafeTerminateProcess' and only
     calls the unsafe TerminateProcess as a final last resort.

   * New windows `kill.exe' fixes a bug where mysqld was being force
     terminated. Issue reported by bruno haleblian and others, see:
     140623#msg-140623MySQL Forums.

   * Replaced `Boolean.parseBoolean' with JDK 1.4 compliant `valueOf'.

   * Changed `connector-mxj.properties' default mysql version to 5.0.37.

   * In testing so far mysqld reliably shuts down cleanly much faster.

   * Added testcase to `com.mysql.management.jmx.AcceptanceTest' which
     demonstrates that `dataDir' is a mutable MBean property.

   * Updated `build.xml' in prep for next release.

   * Changed `SimpleMysqldDynamicMBean' to create `MysqldResource' on
     demand to enable setting of `datadir'. (Rubinger bug groundwork).

   * Clarified the synchronization of `MysqldResource' methods.

   * `SIGHUP' is replaced with `MySQLShutdown<PID>' event.

   * Clarified the immutability of `baseDir', `dataDir', `pidFile',
     `portFile'.

   * Added 5.1.15 binaries to the repository.

   * Removed 5.1.14 binaries from the repository.

   * Added `getDataDir()' to interface `MysqldResourceI'.

   * Added 5.1.14 binaries to repository.

   * Replaced windows *Note `kill.exe': kill. resource with re-written
     version specific to mysqld.

   * Added Patched `StandardSocketFactory' from Connector/J 5-0 HEAD.

   * Ensured 5.1.14 compatibility.

   * Swapped out gpl binaries for v5.0.37.

   * Removed 5.0.22 binaries from the repository.


File: manual.info,  Node: news-connector-mxj-5-0-4,  Next: news-connector-mxj-5-0-3,  Prev: news-connector-mxj-5-0-5,  Up: news-connector-mxj

D.7.9 Changes in MySQL Connector/MXJ 5.0.4 (28 January 2007)
------------------------------------------------------------

*Bugs Fixed*

   * Allow multiple calls to start server from URL connection on
     non-3306 port.  (Bug #24004)

   * Updated `build.xml' to build to handle with different gpl and
     commercial mysqld version numbers.

   * Only populate the options map from the help text if specifically
     requested or in the MBean case.

   * Introduced property for Linux & WinXX to default to 32bit versions.

   * Swapped out gpl binaries for v5.0.27.

   * Swapped out commercial binaries for v5.0.32.

   * Moved mysqld binary resourced into separate jar file NOTICE:
     `CLASSPATH' will now need to `connector-mxj-db-files.jar'.

   * Minor test robustness improvements.

   * Moved default version string out of java class into a text
     editable properties file (`connector-mxj.properties') in the
     resources directory.

   * Fixed test to be tolerant of `/tmp' being a symlink to `/foo/tmp'.


File: manual.info,  Node: news-connector-mxj-5-0-3,  Next: news-connector-mxj-5-0-2,  Prev: news-connector-mxj-5-0-4,  Up: news-connector-mxj

D.7.10 Changes in MySQL Connector/MXJ 5.0.3 (24 June 2006)
----------------------------------------------------------

*Bugs Fixed*

   * Removed unused imports, formatted code, made minor edits to tests.

   * Removed "TeeOutputStream" - no longer needed.

   * Swapped out the mysqld binaries for MySQL v5.0.22.


File: manual.info,  Node: news-connector-mxj-5-0-2,  Next: news-connector-mxj-5-0-1,  Prev: news-connector-mxj-5-0-3,  Up: news-connector-mxj

D.7.11 Changes in MySQL Connector/MXJ 5.0.2 (15 June 2006)
----------------------------------------------------------

*Bugs Fixed*

   * Replaced string parsing with JDBC connection attempt for
     determining if a mysqld is "ready for connections" `CLASSPATH'
     will now need to include Connector/J jar.

   * "platform" directories replace spaces with underscores

   * extracted array and list printing to ListToString utility class

   * Swapped out the mysqld binaries for MySQL v5.0.21

   * Added trace level logging with Aspect/J.  `CLASSPATH' will now
     need to include `lib/aspectjrt.jar'

   * reformatted code

   * altered to be "basedir" rather than "port" oriented.

   * help parsing test reflects current help options

   * insulated users from problems with "." in basedir

   * swapped out the mysqld binaries for MySQL v5.0.18

   * Made tests more robust be deleting the /tmp/test-c.mxj directory
     before running tests.

   * ServerLauncherSocketFactory.shutdown API change: now takes File
     parameter (basedir) instead of port.

   * socket is now "mysql.sock" in datadir

   * added ability to specify "mysql-version" as an url parameter

   * Extended timeout for help string parsing, to avoid cases where the
     help text was getting prematurely flushed, and thus truncated.

   * swapped out the mysqld binaries for MySQL v5.0.19

   * MysqldResource now tied to dataDir as well as basedir (API CHANGE)

   * moved PID file into datadir

   * ServerLauncherSocketFactory.shutdown now works across JVMs.

   * extracted splitLines(String) to Str utility class

   * ServerLauncherSocketFactory.shutdown(port) no longer throws, only
     reports to System.err

   * ServerLauncherSocketFactory now treats URL parameters in the form
     of `&server.foo=null' as `serverOptionMap.put("foo", null)'

   * ServerLauncherSocketFactory.shutdown API change: now takes 2 File
     parameters (basedir, datadir)


File: manual.info,  Node: news-connector-mxj-5-0-1,  Next: news-connector-mxj-5-0-0,  Prev: news-connector-mxj-5-0-2,  Up: news-connector-mxj

D.7.12 Changes in MySQL Connector/MXJ 5.0.1 (Not released)
----------------------------------------------------------

This was an internal only release.

This section has no changelog entries.


File: manual.info,  Node: news-connector-mxj-5-0-0,  Prev: news-connector-mxj-5-0-1,  Up: news-connector-mxj

D.7.13 Changes in MySQL Connector/MXJ 5.0.0 (09 December 2005)
--------------------------------------------------------------

*Bugs Fixed*

   * Removed HelpOptionsParser's need to reference a MysqldResource.

   * Reorganized utils into a single "Utils" collaborator.

   * Minor test tweaks

   * Altered examples and tests to use new Connector/J 5.0 URL syntax
     for launching Connector/MXJ ("jdbc:mysql:mxj://")

   * Swapped out the mysqld binaries for MySQL v5.0.16.

   * Ditched "ClassUtil" (merged with Str).

   * Minor refactorings for type casting and exception handling.


File: manual.info,  Node: mysql-proxy-news,  Prev: news-connector-mxj,  Up: news

D.8 MySQL Proxy Change History
==============================

* Menu:

* mysql-proxy-news-0-8-2::       Changes in MySQL Proxy 0.8.2 (18 August 2011)
* mysql-proxy-news-0-8-1::       Changes in MySQL Proxy 0.8.1 (13 September 2010)
* mysql-proxy-news-0-8-0::       Changes in MySQL Proxy 0.8.0 (21 January 2010)
* mysql-proxy-news-0-7-2::       Changes in MySQL Proxy 0.7.2 (30 June 2009)
* mysql-proxy-news-0-7-1::       Changes in MySQL Proxy 0.7.1 (15 May 2009)
* mysql-proxy-news-0-7-0::       Changes in MySQL Proxy 0.7.0 (Not Released)
* mysql-proxy-news-0-6-1::       Changes in MySQL Proxy 0.6.1 (06 February 2008)
* mysql-proxy-news-0-6-0::       Changes in MySQL Proxy 0.6.0 (11 September 2007)
* mysql-proxy-news-0-5-1::       Changes in MySQL Proxy 0.5.1 (30 June 2007)
* mysql-proxy-news-0-5-0::       Changes in MySQL Proxy 0.5.0 (19 June 2007)


File: manual.info,  Node: mysql-proxy-news-0-8-2,  Next: mysql-proxy-news-0-8-1,  Prev: mysql-proxy-news,  Up: mysql-proxy-news

D.8.1 Changes in MySQL Proxy 0.8.2 (18 August 2011)
---------------------------------------------------

MySQL Proxy 0.8.2 is a maintenance release and focuses on these areas:

   * Adding the protocol changes of MySQL 5.5 and later

   * Removing the `admin' plugin from the list of default plugins, as
     it requires configuration since 0.8.1

*Note_to Windows Users*
   * The Microsoft Visual C++ runtime libraries are now a requirement
     for running MySQL Proxy. Users that do not have these libraries
     must download and install the Microsoft Visual C++ 2008 Service
     Pack 1 Redistributable Package MFC Security Update. For the
     current Proxy version, use the following link to obtain the
     package:

          `http://www.microsoft.com/download/en/details.aspx?displaylang=en&id=26368'

     (Bug #12836100)

*Functionality Added or Changed*

   * Removed the `admin' plugin from the list of default plugins, as it
     requires configuration since 0.8.1.

   * Added support for `OUT' parameters in prepared statements in
     stored procedures with MySQL 5.5.

   * Added support for decoding _all_ data types of the row-based
     replication protocol.

   * Added support for binary log checksums.

*Bugs Fixed*

   * Fixed handling of stored procedures with cursors with MySQL 5.5.
     (Bug #61998)

   * A crash occurred if the file named with the `--defaults-file'
     option did not exist.  (Bug #59790)

   * The first characters of log messages were stripped.  (Bug #59790)

   * A memory leak occurred if connection pooling was used.  (Bug
     #56620)

   * A bogus timestamp log was produced if state tracking was not
     compiled in.

   * A crash could occur if run under Valgrind.

   * Fixed handling of `used columns' with row-based replication.


File: manual.info,  Node: mysql-proxy-news-0-8-1,  Next: mysql-proxy-news-0-8-0,  Prev: mysql-proxy-news-0-8-2,  Up: mysql-proxy-news

D.8.2 Changes in MySQL Proxy 0.8.1 (13 September 2010)
------------------------------------------------------

*Functionality Added or Changed*

   * Allow interception of *Note `LOAD DATA INFILE': load-data. and
     *Note `SHOW ERRORS': show-errors.  statements.

   * The unused `network_mysqld_com_query_result_track_state()'
     function has been deprecated.

   * `chassis_set_fdlimit()' has been deprecated in favor of
     `chassis_fdlimit_set()'.

   * Shutdown hooks were added to free the global memory of third-party
     libraries such as `openssl'.

   * `con->in_load_data_local' has been removed.

*Bugs Fixed*

   * The admin plugin had an undocumented default value for
     `--admin-password'.  (Bug #53429)

   * Use of *Note `LOAD DATA LOCAL INFILE': load-data. caused the
     connection between the client and MySQL Proxy to abort.  (Bug
     #51864)

   * If the backend MySQL server went down, and then the clock on the
     MySQL Proxy host went backward (for example, during daylight
     saving time adjustments), Proxy stopped forwarding queries to the
     backend.  (Bug #50806)

   * `network_address_set_address()->network_address_set_address_ip()'
     called `gethostbyname()' which was not reentrant. This meant that
     a MySQL Proxy plugin needed to guard all calls to
     `network_address_set_address()' with a mutex.
     `network_address_set_address()' has been modified to be thread
     safe.  (Bug #49099)

   * The hard limit was fixed for the case where the fdlimit was set.
     (Bug #48120)

   * MySQL Proxy returned an error message with a nonstandard SQL State
     when all backends were down:

          "#07000(proxy) all backends are down"

     This caused issues for clients with `retry' logic, as they could
     not handle these `custom' SQL States.  (Bug #45417)

   * If MySQL Proxy used a UNIX socket, it did not remove the socket
     file at termination time.  (Bug #38415)

   * The `--proxy-read-only-backend-addresses' option did not work.
     (Bug #38341, Bug #11749171)

   * When running `configure' to build, the error message relating to
     the `lua' libraries could be misleading. The wording and build
     advice have been updated.


File: manual.info,  Node: mysql-proxy-news-0-8-0,  Next: mysql-proxy-news-0-7-2,  Prev: mysql-proxy-news-0-8-1,  Up: mysql-proxy-news

D.8.3 Changes in MySQL Proxy 0.8.0 (21 January 2010)
----------------------------------------------------

*Functionality Added or Changed*

   * The `--no-daemon' has been renamed to The `--daemon'. By default,
     MySQL Proxy now starts in foreground mode. Use the `--daemon'
     option to override this and start in daemon mode.

*Bugs Fixed*

   * A memory leak occurred in MySQL Proxy if clients older than MySQL
     4.1 connected to it.  (Bug #50993)

   * A segmentation fault occurred in MySQL Proxy if clients older than
     MySQL 4.1 connected to it.  (Bug #48641)

   * MySQL Proxy would load a configuration file with unsafe
     permissions, which could permit password information to be exposed
     through the file. MySQL Proxy now refuses to load a configuration
     file with unsafe permissions.  (Bug #47589)

   * Several supplied scripts were updated to account for flag and
     structure changes:

        * `active-transactions.lua' was updated to use the
          `resultset_is_needed' flag.

        * `ro-balance.lua' was updated to use the `resultset_is_needed'
          flag and updated `proxy.connection.dst.name' structure.

        * `rw-splitting.lua' was updated to use the
          `resultset_is_needed' flag and updated `proxy.connections'
          structure.

     (Bug #47349, Bug #45408, Bug #47345, Bug #43424, Bug #42841, Bug
     #46141)

   * The line numbers provided in stack traces were off by one.  (Bug
     #47348)

   * MySQL Proxy accepted more than one address in the value of the
     `--proxy-backend-addresses' option. You should specify one
     `--proxy-backend-addresses' option for each backend address.  (Bug
     #47273)

   * MySQL Proxy returned the wrong version string internally from the
     `proxy.PROXY_VERSION' constant.  (Bug #45996)

   * MySQL Proxy could stop accepting network packets if it received a
     large number of packets. The listen queue has been extended to
     permit a larger backlog.  (Bug #45878, Bug #43278)

   * Due to a memory leak, memory usage for each new connection to the
     proxy increased, leading to very high consumption.  (Bug #45272)

   * MySQL Proxy failed to work with certain versions of MySQL,
     including MySQL 5.1.15, where a change in the MySQL protocol
     existed. Now Proxy denies `COM_CHANGE_USER' commands when it is
     connected to MySQL 5.1.14 to 5.1.17 servers by sending back an
     error: `COM_CHANGE_USER is broken on 5.1.14-.17, please upgrade
     the MySQL Server'.  (Bug #45167) See also Bug #25371.

   * Logging to `syslog' with the `--log-use-syslog' option did not
     work.  (Bug #36431)

   * MySQL Proxy could incorrectly insert `NULL' values into the
     returned result set, even though non-`NULL' values were returned
     in the original query.  (Bug #35729)

   * MySQL Proxy raised an error when processing query packets larger
     than 16MB.  (Bug #35202)


File: manual.info,  Node: mysql-proxy-news-0-7-2,  Next: mysql-proxy-news-0-7-1,  Prev: mysql-proxy-news-0-8-0,  Up: mysql-proxy-news

D.8.4 Changes in MySQL Proxy 0.7.2 (30 June 2009)
-------------------------------------------------

*Bugs Fixed*

   * On Windows, MySQL Proxy might not find the required modules during
     initialization. The core code has been updated to find the
     components correctly, and the Lua-based C modules are prefixed
     with `lua-' and Lua plugins with `plugin-'.  (Bug #45833)


File: manual.info,  Node: mysql-proxy-news-0-7-1,  Next: mysql-proxy-news-0-7-0,  Prev: mysql-proxy-news-0-7-2,  Up: mysql-proxy-news

D.8.5 Changes in MySQL Proxy 0.7.1 (15 May 2009)
------------------------------------------------

*Bugs Fixed*

   * Due to a memory leak, memory usage for each new connection to the
     proxy increased, leading to very high consumption.  (Bug #45272)

   * The port number was reported incorrectly in
     `proxy.connection.client.address'.  (Bug #43313)

   * Result sets with more than 250 fields could cause MySQL Proxy to
     crash.  (Bug #43078)

   * MySQL Proxy was unable to increase its own maximum number of open
     files according to the limit specified by the `--max-open-files'
     option, if the limit was less than 8192. When set to debug level,
     Proxy now reports the open files limit and when the limit has been
     updated.  (Bug #42783)

   * MySQL Proxy crashed when connecting to a MySQL 4.0 server. Now it
     generates an error message instead.  (Bug #38601)

   * When using the `rw-splitting.lua' script, you could get an error
     when talking to the backend server:

          2008-07-28 18:00:30: (critical) (read_query) [string
          "/usr/local/share/mysql-proxy/rw-splitting.l..."]:218: bad argument #1 to 'ipairs' (table
          expected, got userdata)

     This led to Proxy closing the connection to the configured MySQL
     backend.  (Bug #38419)

   * When using MySQL Proxy with multiple backends, failure of one
     backend caused Proxy to disconnect all backends and stop routing
     requests.  (Bug #34793)


File: manual.info,  Node: mysql-proxy-news-0-7-0,  Next: mysql-proxy-news-0-6-1,  Prev: mysql-proxy-news-0-7-1,  Up: mysql-proxy-news

D.8.6 Changes in MySQL Proxy 0.7.0 (Not Released)
-------------------------------------------------

*Functionality Added or Changed*

   * Support for using a configuration file, in addition to the
     command-line options, has been added. To specify such a file, use
     the `--defaults-file=`file_name'' command-line option. See *Note
     mysql-proxy-configuration::.  (Bug #30206)

   * A number of the internal structures developed for use with Lua
     scripts that work with MySQL Proxy have been updated and
     harmonized to make their meaning and contents easier to use and
     consistent across multiple locations.

        * The address information has been updated. Instead of a
          combined `ip:port' structure that you had to parse to extract
          the individual information, you can now access that
          information directly. For example, instead of structures
          providing a single `.address' item, you now have these items:
          `name' (the combined `ip:port'), `address' (the IP address),
          and `port' (port number). In addition, all addresses now
          supply both the `src' (source) and `dst' (destination) socket
          information for both ends of connections.

          Some familiar structures have been updated to accommodate
          this information:

             * `proxy.connection.client.address' is
               `proxy.connection.client.src.name'

             * `proxy.connection.server.address' is
               `proxy.connection.server.dst.name'

        * `proxy.backends' is now in `proxy.global.backends' The
          `.address' field of each backend is an address-object as
          described earlier. For example, `proxy.backends[1].address' is
          `proxy.global.backends[1].dst.name'.

        * The `read_auth()' and `read_handshake()' functions no longer
          receive an `auth' parameter. Instead, all the data is
          available in the connection tables.

          In `read_handshake()', you access the information through the
          global `proxy.connection' table:

          0.6                             0.7
          `auth.thread_id'                `proxy.connection.server.thread_id'
          `auth.mysqld_version'           `proxy.connection.server.mysqld_version'
          `auth.server_addr'              `proxy.connection.server.dst.name'
          `auth.client_addr'              `proxy.connection.client.src.name'
          `auth.scramble'                 `proxy.connection.server.scramble_buffer'

          In `read_auth()', you can use the following:

          0.6                             0.7
          `auth.username'                 `proxy.connection.client.username'
          `auth.password'                 `proxy.connection.client.scrambled_password'
          `auth.default_db'               `proxy.connection.client.default_db'
          `auth.server_addr'              `proxy.connection.server.dst.name'
          `auth.client_addr'              `proxy.connection.client.src.name'

        * In the `proxy.queries:append()' function, a third parameter
          is an (optional) table with options specific to the this
          packet. Specifically, if you want to have access to the
          result set in the `read_query_result()' hook, you must set
          the `resultset_is_needed' flag:

               proxy.queries:append( 1, ..., { resultset_is_needed = true } )

          For more information, see *Note
          mysql-proxy-scripting-structures-queries::.

        * `proxy.backends' is now in `proxy.global.backends'.

*Bugs Fixed*

   * *Security Enhancement*: Accessing MySQL Proxy using a client or
     backend from earlier than MySQL 4.1 resulted in Proxy aborting
     with an assertion.  This is because Proxy supports only MySQL 4.1
     or higher. Proxy now reports a fault.  (Bug #31419)

   * MySQL Proxy was configured with the `LUA_PATH' and `LUA_CPATH'
     directory locations according to the build host rather than the
     execution host. In addition, during installation, certain Lua
     source files could be installed into the incorrect locations.
     (Bug #44877, Bug #44497)

   * Using MySQL Proxy with very large return data sets from queries
     could cause a crash, with or without manipulation of the data set
     within the Lua engine.  (Bug #39332)

   * MySQL Proxy terminated if a submitted packet was smaller than
     expected by the protocol.  (Bug #36743)

   * When using MySQL Proxy in a master-master replication scenario,
     Proxy failed to identify failure in one of the replication masters
     and did not redirect connections to the other master.  (Bug #35295)


File: manual.info,  Node: mysql-proxy-news-0-6-1,  Next: mysql-proxy-news-0-6-0,  Prev: mysql-proxy-news-0-7-0,  Up: mysql-proxy-news

D.8.7 Changes in MySQL Proxy 0.6.1 (06 February 2008)
-----------------------------------------------------

*Functionality Added or Changed*

   * Fixed assertions on write errors.

   * Fixed sending fake server-greetings in `connect_server()'.

   * Fixed error handling for socket functions on Windows.

   * Added new features to `run-tests.lua'.


File: manual.info,  Node: mysql-proxy-news-0-6-0,  Next: mysql-proxy-news-0-5-1,  Prev: mysql-proxy-news-0-6-1,  Up: mysql-proxy-news

D.8.8 Changes in MySQL Proxy 0.6.0 (11 September 2007)
------------------------------------------------------

*Functionality Added or Changed*

   * When using read/write splitting and the `rw-splitting.lua' example
     script, connecting a second user to the proxy returns an error
     message.  (Bug #30867)

   * Added support in `read_query_result()' to overwrite the result set.

   * By default, MySQL Proxy now starts in daemon mode. Use the new
     `--no-daemon' option to override this. Added the `--pid-file'
     option for writing the process ID to a file after becoming a
     daemon.

   * Added hooks for `read_auth()', `read_handshake()' and
     `read_auth_result()'.

   * Added handling of `proxy.connection.backend_ndx' in
     `connect_server()' and `read_query()' to support read/write
     splitting.

   * Added support for `proxy.response.packets'.

   * Added test cases.

   * Added `--no-proxy' to disable the proxy.

   * Added support for listening UNIX sockets.

   * Added a global Lua-scope `proxy.global.*'.

   * Added connection pooling.

*Bugs Fixed*

   * Fixed an assertion on `COM_BINLOG_DUMP'.  (Bug #29764)

   * Fixed an assertion on result-packets like `[field-len | fields |
     EOF | ERR]'.  (Bug #29732)

   * Fixed an assertion that MySQL Proxy raised at login time if a
     client specified no password and no default database.  (Bug #29719)

   * Fixed an assertion at `COM_SHUTDOWN'.  (Bug #29719)

   * Fixed a crash if `proxy.connection' is used in `connect_server()'.

   * Fixed the `glib2' check to require at least `glib2' 2.6.0.

   * Fixed an assertion at connect time when all backends are down.

   * Fixed connection stalling if `read_query_result()' raised an
     assertion.

   * Fixed length encoding on `proxy.resultsets'.

   * Fixed compilation on win32.

   * Fixed an assertion when connecting to MySQL 6.0.1.

   * Fixed decoding of length-encoded ints for 3-byte notation.

   * Fixed `inj.resultset.affected_rows' on *Note `SELECT': select.
     queries.

   * Fixed handling of (SQL) `NULL' in result sets.

   * Fixed a memory leak when `proxy.response.*' is used.


File: manual.info,  Node: mysql-proxy-news-0-5-1,  Next: mysql-proxy-news-0-5-0,  Prev: mysql-proxy-news-0-6-0,  Up: mysql-proxy-news

D.8.9 Changes in MySQL Proxy 0.5.1 (30 June 2007)
-------------------------------------------------

*Functionality Added or Changed*

   * Added `resultset.affected_rows' and `resultset.insert_id'.

   * Changed `--proxy.profiling' to `--proxy-skip-profiling'.

   * Added missing dependency to `libmysqlclient-dev' to the `INSTALL'
     file.

   * Added `inj.query_time' and `inj.response_time' into the Lua
     scripts.

   * Added support for pre-4.1 passwords in a 4.1 connection.

   * Added script examples for rewriting and injection.

   * Added `proxy.VERSION'.

   * Added support for UNIX sockets.

   * Added protection against duplicate result sets from a script.

*Bugs Fixed*

   * Fixed mysql check in `configure' to die when `mysql.h' isn't
     detected.

   * Fixed handling of duplicate ERR on `COM_CHANGE_USER' in MySQL
     5.1.18+.

   * Fixed a compile error with MySQL 4.1.x on missing `COM_STMT_*'.

   * Fixed a crash on fields longer than 250 bytes when the result set
     is inspected.

   * Fixed a warning if `connect_server()' is not provided.

   * Fixed an assertion when an error occurs at initial script exec
     time.

   * Fixed an assertion when `read_query_result()' is not provided when
     `PROXY_SEND_QUERY' is used.


File: manual.info,  Node: mysql-proxy-news-0-5-0,  Prev: mysql-proxy-news-0-5-1,  Up: mysql-proxy-news

D.8.10 Changes in MySQL Proxy 0.5.0 (19 June 2007)
--------------------------------------------------

This is the first beta release.

*Bugs Fixed*

   * Added `automake'/`autoconf' support.

   * Added `CMake' support.


File: manual.info,  Node: restrictions,  Prev: news,  Up: Top

Appendix E Restrictions and Limits
**********************************

* Menu:

* stored-program-restrictions::  Restrictions on Stored Programs
* cursor-restrictions::          Restrictions on Server-Side Cursors
* subquery-restrictions::        Restrictions on Subqueries
* view-restrictions::            Restrictions on Views
* xa-restrictions::              Restrictions on XA Transactions
* charset-restrictions::         Restrictions on Character Sets
* limits::                       Limits in MySQL

The discussion here describes restrictions that apply to the use of
MySQL features such as subqueries or views.


File: manual.info,  Node: stored-program-restrictions,  Next: cursor-restrictions,  Prev: restrictions,  Up: restrictions

E.1 Restrictions on Stored Programs
===================================

Some of the restrictions noted here apply to all stored routines; that
is, both to stored procedures and stored functions. Some of these
restrictions apply to stored functions but not to stored procedures.

The restrictions for stored functions also apply to triggers.

Stored routines cannot contain arbitrary SQL statements. The following
statements are not permitted:

   * The table-maintenance statements *Note `CHECK TABLE': check-table.
     and *Note `OPTIMIZE TABLE': optimize-table. This restriction is
     lifted beginning with MySQL 5.0.17.

   * The locking statements *Note `LOCK TABLES': lock-tables. and *Note
     `UNLOCK TABLES': lock-tables.

   * *Note `ALTER VIEW': alter-view. (Before MySQL 5.0.46, this
     restriction is enforced only for stored functions.)

   * *Note `LOAD DATA': load-data. and `LOAD TABLE'.

   * SQL prepared statements (*Note `PREPARE': prepare, *Note
     `EXECUTE': execute, *Note `DEALLOCATE PREPARE':
     deallocate-prepare.).  Implication: You cannot use dynamic SQL
     within stored routines (where you construct dynamically statements
     as strings and then execute them). This restriction is lifted as
     of MySQL 5.0.13 for stored procedures; it still applies to stored
     functions and triggers.

     Generally, statements not permitted in SQL prepared statements are
     also not permitted in stored programs. For a list of statements
     supported as prepared statements, see *Note
     sql-syntax-prepared-statements::.

   * Inserts cannot be delayed. *Note `INSERT DELAYED': insert-delayed.
     syntax is accepted but the statement is handled as a normal *Note
     `INSERT': insert.

   * Within stored programs (stored procedures and functions, and
     triggers), the parser treats *Note `BEGIN [WORK]': commit.  as the
     beginning of a *Note `BEGIN ... END': begin-end. block. Begin a
     transaction in this context with *Note `START TRANSACTION':
     commit. instead.

For stored functions (but not stored procedures), the following
additional statements or operations are not permitted:

   * Statements that perform explicit or implicit commit or rollback.
     Support for these statements is not required by the SQL standard,
     which states that each DBMS vendor may decide whether to permit
     them.

   * Statements that return a result set. This includes *Note `SELECT':
     select. statements that do not have an `INTO VAR_LIST' clause and
     other statements such as *Note `SHOW': show, *Note `EXPLAIN':
     explain, and *Note `CHECK TABLE': check-table. A function can
     process a result set either with *Note `SELECT ... INTO VAR_LIST':
     select-into. or by using a cursor and *Note `FETCH': fetch.
     statements.  See *Note select-into::, and *Note cursors::.

   * *Note `FLUSH': flush. statements.

   * Before MySQL 5.0.10, stored functions created with *Note `CREATE
     FUNCTION': create-function. must not contain references to tables,
     with limited exceptions. They may include some `SET' statements
     that contain table references, for example `SET a:= (SELECT
     MAX(id) FROM t)', and *Note `SELECT': select. statements that fetch
     values directly into variables, for example `SELECT i INTO var1
     FROM t'.

   * Stored functions cannot be used recursively.

   * Within a stored function or trigger, it is not permitted to modify
     a table that is already being used (for reading or writing) by the
     statement that invoked the function or trigger.

   * If you refer to a temporary table multiple times in a stored
     function under different aliases, a `Can't reopen table:
     'TBL_NAME`''' error occurs, even if the references occur in
     different statements within the function.

   * A stored function acquires table locks before executing, to avoid
     inconsistency in the binary log due to mismatch of the order in
     which statements execute and when they appear in the log.
     Statements that invoke a function are recorded rather than the
     statements executed within the function.  Consequently, stored
     functions that update the same underlying tables do not execute in
     parallel. In contrast, stored procedures do not acquire
     table-level locks. All statements executed within stored
     procedures are written to the binary log. See *Note
     stored-programs-logging::.

Although some restrictions normally apply to stored functions and
triggers but not to stored procedures, those restrictions do apply to
stored procedures if they are invoked from within a stored function or
trigger. For example, if you use *Note `FLUSH': flush. in a stored
procedure, that stored procedure cannot be called from a stored
function or trigger.

It is possible for the same identifier to be used for a routine
parameter, a local variable, and a table column. Also, the same local
variable name can be used in nested blocks. For example:

     CREATE PROCEDURE p (i INT)
     BEGIN
       DECLARE i INT DEFAULT 0;
       SELECT i FROM t;
       BEGIN
         DECLARE i INT DEFAULT 1;
         SELECT i FROM t;
       END;
     END;

In such cases the identifier is ambiguous and the following precedence
rules apply:

   * A local variable takes precedence over a routine parameter or
     table column

   * A routine parameter takes precedence over a table column

   * A local variable in an inner block takes precedence over a local
     variable in an outer block

The behavior that variables take precedence over table columns is
nonstandard.

Use of stored routines can cause replication problems. This issue is
discussed further in *Note stored-programs-logging::.

`INFORMATION_SCHEMA' does not have a `PARAMETERS' table until MySQL
5.5, so applications that need to acquire routine parameter information
at runtime must use workarounds such as parsing the output of `SHOW
CREATE' statements or the `param_list' column of the `mysql.proc'
table. `param_list' contents can be processed from within a stored
routine, unlike the output from *Note `SHOW': show.

The `--replicate-wild-do-table=DB_NAME.TBL_NAME' option applies to
tables, views, and triggers. It does not apply to stored procedures and
functions, or events. To filter statements operating on the latter
objects, use one or more of the `--replicate-*-db' options.

There are no stored routine debugging facilities.

Before MySQL 5.0.17, *Note `CALL': call.  statements cannot be
prepared. This true both for server-side prepared statements and for
SQL prepared statements.

MySQL does not support `UNDO' handlers.

MySQL does not support `FOR' loops.

To prevent problems of interaction between server threads, when a
client issues a statement, the server uses a snapshot of routines and
triggers available for execution of the statement. That is, the server
calculates a list of procedures, functions, and triggers that may be
used during execution of the statement, loads them, and then proceeds
to execute the statement. This means that while the statement executes,
it will not see changes to routines performed by other threads.

For triggers, the following additional restrictions apply:

   * Triggers currently are not activated by foreign key actions.

   * The *Note `RETURN': return. statement is not permitted in
     triggers, which cannot return a value. To exit a trigger
     immediately, use the *Note `LEAVE': leave-statement.  statement.

   * Triggers are not permitted on tables in the `mysql' database.

   * The trigger cache does not detect when metadata of the underlying
     objects has changed. If a trigger uses a table and the table has
     changed since the trigger was loaded into the cache, the trigger
     operates using the outdated metadata.


File: manual.info,  Node: cursor-restrictions,  Next: subquery-restrictions,  Prev: stored-program-restrictions,  Up: restrictions

E.2 Restrictions on Server-Side Cursors
=======================================

Server-side cursors are implemented beginning with the C API in MySQL
5.0.2 using the *Note `mysql_stmt_attr_set()': mysql-stmt-attr-set.
function. A server-side cursor enables a result set to be generated on
the server side, but not transferred to the client except for those
rows that the client requests. For example, if a client executes a
query but is only interested in the first row, the remaining rows are
not transferred.

In MySQL, a server-side cursor is materialized into an internal
temporary table. Initially, this is a `MEMORY' table, but is converted
to a `MyISAM' table when its size exceeds the minimum value of the
`max_heap_table_size' and `tmp_table_size' system variables.  Note that
the same restrictions apply to internal temporary tables created to
hold the result set for a cursor as for other uses of internal
temporary tables. See *Note internal-temporary-tables::. (Beginning
with MySQL 5.0.14, the same temporary-table implementation also is used
for cursors in stored routines.) One limitation of the implementation
is that for a large result set, retrieving its rows through a cursor
might be slow.

Cursors are read only; you cannot use a cursor to update rows.

`UPDATE WHERE CURRENT OF' and `DELETE WHERE CURRENT OF' are not
implemented, because updatable cursors are not supported.

Cursors are nonholdable (not held open after a commit).

Cursors are asensitive.

Cursors are nonscrollable.

Cursors are not named. The statement handler acts as the cursor ID.

You can have open only a single cursor per prepared statement. If you
need several cursors, you must prepare several statements.

You cannot use a cursor for a statement that generates a result set if
the statement is not supported in prepared mode. This includes
statements such as *Note `CHECK TABLE': check-table, `HANDLER READ', and
*Note `SHOW BINLOG EVENTS': show-binlog-events.


File: manual.info,  Node: subquery-restrictions,  Next: view-restrictions,  Prev: cursor-restrictions,  Up: restrictions

E.3 Restrictions on Subqueries
==============================

   * In MySQL 5.0 before 5.0.36, if you compare a `NULL' value to a
     subquery using `ALL', `ANY', or `SOME', and the subquery returns
     an empty result, the comparison might evaluate to the nonstandard
     result of `NULL' rather than to `TRUE' or `FALSE'.

   * A subquery's outer statement can be any one of: *Note `SELECT':
     select, *Note `INSERT': insert, *Note `UPDATE': update, *Note
     `DELETE': delete, *Note `SET': set-option, or *Note `DO': do.

   * Subquery optimization for `IN' is not as effective as for the `='
     operator or for the `IN(VALUE_LIST)' operator.

     A typical case for poor `IN' subquery performance is when the
     subquery returns a small number of rows but the outer query
     returns a large number of rows to be compared to the subquery
     result.

     The problem is that, for a statement that uses an `IN' subquery,
     the optimizer rewrites it as a correlated subquery. Consider the
     following statement that uses an uncorrelated subquery:

          SELECT ... FROM t1 WHERE t1.a IN (SELECT b FROM t2);

     The optimizer rewrites the statement to a correlated subquery:

          SELECT ... FROM t1 WHERE EXISTS (SELECT 1 FROM t2 WHERE t2.b = t1.a);

     If the inner and outer queries return M and N rows, respectively,
     the execution time becomes on the order of O(MxN), rather than
     O(M+N) as it would be for an uncorrelated subquery.

     An implication is that an `IN' subquery can be much slower than a
     query written using an `IN(VALUE_LIST)' operator that lists the
     same values that the subquery would return.

   * In general, you cannot modify a table and select from the same
     table in a subquery. For example, this limitation applies to
     statements of the following forms:

          DELETE FROM t WHERE ... (SELECT ... FROM t ...);
          UPDATE t ... WHERE col = (SELECT ... FROM t ...);
          {INSERT|REPLACE} INTO t (SELECT ... FROM t ...);

     Exception: The preceding prohibition does not apply if you are
     using a subquery for the modified table in the `FROM' clause.
     Example:

          UPDATE t ... WHERE col = (SELECT * FROM (SELECT ... FROM t...) AS _t ...);

     Here the result from the subquery in the `FROM' clause is stored
     as a temporary table, so the relevant rows in `t' have already been
     selected by the time the update to `t' takes place.

   * Row comparison operations are only partially supported:

        * For `EXPR IN (SUBQUERY)', EXPR can be an N-tuple (specified
          using row constructor syntax) and the subquery can return
          rows of N-tuples.

        * For `EXPR OP {ALL|ANY|SOME} (SUBQUERY)', EXPR must be a
          scalar value and the subquery must be a column subquery; it
          cannot return multiple-column rows.

     In other words, for a subquery that returns rows of N-tuples, this
     is supported:

          (VAL_1, ..., VAL_N) IN (SUBQUERY)

     But this is not supported:

          (VAL_1, ..., VAL_N) OP {ALL|ANY|SOME} (SUBQUERY)

     The reason for supporting row comparisons for `IN' but not for the
     others is that `IN' is implemented by rewriting it as a sequence
     of `=' comparisons and `AND' operations.  This approach cannot be
     used for `ALL', `ANY', or `SOME'.

   * Prior to MySQL 5.0.26, row constructors were not well optimized;
     of the following two equivalent expressions, only the second could
     be optimized:

          (col1, col2, ...) = (val1, val2, ...)
          col1 = val1 AND col2 = val2 AND ...

     In MySQL 5.0.26 and later, all row equalities are converted into
     conjunctions of equalities between row elements, and handled by
     the optimizer in the same way. (Bug #16081)

   * Subqueries in the `FROM' clause cannot be correlated subqueries.
     They are materialized in whole (evaluated to produce a result set)
     before evaluating the outer query, so they cannot be evaluated per
     row of the outer query.

   * MySQL does not support `LIMIT' in subqueries for certain subquery
     operators:

          mysql> SELECT * FROM t1
              ->   WHERE s1 IN (SELECT s2 FROM t2 ORDER BY s1 LIMIT 1);
          ERROR 1235 (42000): This version of MySQL doesn't yet support
           'LIMIT & IN/ALL/ANY/SOME subquery'

   * The optimizer is more mature for joins than for subqueries, so in
     many cases a statement that uses a subquery can be executed more
     efficiently if you rewrite it as a join.

     An exception occurs for the case where an `IN' subquery can be
     rewritten as a *Note `SELECT DISTINCT': select. join. Example:

          SELECT col FROM t1 WHERE id_col IN (SELECT id_col2 FROM t2 WHERE CONDITION);

     That statement can be rewritten as follows:

          SELECT DISTINCT col FROM t1, t2 WHERE t1.id_col = t2.id_col AND CONDITION;

     But in this case, the join requires an extra `DISTINCT' operation
     and is not more efficient than the subquery.

   * MySQL permits a subquery to refer to a stored function that has
     data-modifying side effects such as inserting rows into a table.
     For example, if `f()' inserts rows, the following query can modify
     data:

          SELECT ... WHERE x IN (SELECT f() ...);

     This behavior is nonstandard (not permitted by the SQL standard).
     In MySQL, it can produce indeterminate results because `f()' might
     be executed a different number of times for different executions
     of a given query depending on how the optimizer chooses to handle
     it.

     For replication, one implication of this indeterminism is that
     such a query can produce different results on the master and its
     slaves.

   * Possible future optimization: A subquery in the `FROM' clause is
     evaluated by materializing the result into a temporary table, and
     this table does not use indexes. This does not allow the use of
     indexes in comparison with other tables in the query, although
     that might be useful.

   * Possible future optimization: MySQL does not rewrite the join
     order for subquery evaluation. In some cases, a subquery could be
     executed more efficiently if MySQL rewrote it as a join.  This
     would give the optimizer a chance to choose between more execution
     plans. For example, it could decide whether to read one table or
     the other first.

     Example:

          SELECT a FROM outer_table AS ot
          WHERE a IN (SELECT a FROM inner_table AS it WHERE ot.b = it.b);

     For that query, MySQL always scans `outer_table' first and then
     executes the subquery on `inner_table' for each row. If
     `outer_table' has a lot of rows and `inner_table' has few rows,
     the query probably will not be as fast as it could be.

     The preceding query could be rewritten like this:

          SELECT a FROM outer_table AS ot, inner_table AS it
          WHERE ot.a = it.a AND ot.b = it.b;

     In this case, we can scan the small table (`inner_table') and look
     up rows in `outer_table', which will be fast if there is an index
     on `(ot.a,ot.b)'.

   * Possible future optimization: A correlated subquery is evaluated
     for each row of the outer query. A better approach is that if the
     outer row values do not change from the previous row, do not
     evaluate the subquery again. Instead, use its previous result.

   * Possible future optimization: If a subquery in the `FROM' clause
     resembles a view to which the merge algorithm can be applied,
     rewrite the query and apply the merge algorithm so that indexes
     can be used. The following statement contains such a subquery:

          SELECT * FROM (SELECT * FROM t1 WHERE t1.t1_col) AS _t1, t2 WHERE t2.t2_col;

     The statement can be rewritten as a join like this:

          SELECT * FROM t1, t2 WHERE t1.t1_col AND t2.t2_col;

     This type of rewriting would provide two benefits:

        * It avoids the use of a temporary table for which no indexes
          can be used. In the rewritten query, the optimizer can use
          indexes on `t1'.

        * It gives the optimizer more freedom to choose between
          different execution plans. For example, rewriting the query
          as a join enables the optimizer to use `t1' or `t2' first.

   * Possible future optimization: For `IN', `= ANY', `<> ANY', `=
     ALL', and `<> ALL' with uncorrelated subqueries, use an in-memory
     hash for a result or a temporary table with an index for larger
     results.  Example:

          SELECT a FROM big_table AS bt
          WHERE non_key_field IN (SELECT non_key_field FROM TABLE WHERE CONDITION)

     In this case, we could create a temporary table:

          CREATE TABLE t (key (non_key_field))
          (SELECT non_key_field FROM TABLE WHERE CONDITION)

     Then, for each row in `big_table', do a key lookup in `t' based on
     `bt.non_key_field'.


File: manual.info,  Node: view-restrictions,  Next: xa-restrictions,  Prev: subquery-restrictions,  Up: restrictions

E.4 Restrictions on Views
=========================

View processing is not optimized:

   * It is not possible to create an index on a view.

   * Indexes can be used for views processed using the merge algorithm.
     However, a view that is processed with the temptable algorithm is
     unable to take advantage of indexes on its underlying tables
     (although indexes can be used during generation of the temporary
     tables).

Subqueries cannot be used in the `FROM' clause of a view.

There is a general principle that you cannot modify a table and select
from the same table in a subquery. See *Note subquery-restrictions::.

The same principle also applies if you select from a view that selects
from the table, if the view selects from the table in a subquery and
the view is evaluated using the merge algorithm.  Example:

     CREATE VIEW v1 AS
     SELECT * FROM t2 WHERE EXISTS (SELECT 1 FROM t1 WHERE t1.a = t2.a);

     UPDATE t1, v2 SET t1.a = 1 WHERE t1.b = v2.b;

If the view is evaluated using a temporary table, you _can_ select from
the table in the view subquery and still modify that table in the outer
query. In this case the view will be stored in a temporary table and
thus you are not really selecting from the table in a subquery and
modifying it `at the same time.' (This is another reason you might wish
to force MySQL to use the temptable algorithm by specifying `ALGORITHM
= TEMPTABLE' in the view definition.)

You can use *Note `DROP TABLE': drop-table. or *Note `ALTER TABLE':
alter-table. to drop or alter a table that is used in a view
definition. No warning results from the `DROP' or `ALTER' operation,
even though this invalidates the view. Instead, an error occurs later,
when the view is used. *Note `CHECK TABLE': check-table. can be used to
check for views that have been invalidated by `DROP' or `ALTER'
operations.

A view definition is `frozen' by certain statements:

   * If a statement prepared by *Note `PREPARE': prepare. refers to a
     view, the view definition seen each time the statement is executed
     later will be the definition of the view at the time it was
     prepared. This is true even if the view definition is changed
     after the statement is prepared and before it is executed.
     Example:

          CREATE VIEW v AS SELECT RAND();
          PREPARE s FROM 'SELECT * FROM v';
          ALTER VIEW v AS SELECT NOW();
          EXECUTE s;

     The result returned by the *Note `EXECUTE': execute. statement is
     a random number, not the current date and time.

   * If a statement in a stored routine refers to a view, the view
     definition seen by the statement are its definition the first time
     that statement is executed. For example, this means that if the
     statement is executed in a loop, further iterations of the
     statement see the same view definition, even if the definition is
     changed later in the loop. Example:

          CREATE VIEW v AS SELECT 1;
          delimiter //
          CREATE PROCEDURE p ()
          BEGIN
            DECLARE i INT DEFAULT 0;
            WHILE i < 5 DO
              SELECT * FROM v;
              SET i = i + 1;
              ALTER VIEW v AS SELECT 2;
            END WHILE;
          END;
          //
          delimiter ;
          CALL p();

     When the procedure `p()' is called, the *Note `SELECT': select.
     returns 1 each time through the loop, even though the view
     definition is changed within the loop.

     As of MySQL 5.0.46, *Note `ALTER VIEW': alter-view.  is prohibited
     within stored routines, so this restriction does not apply.

With regard to view updatability, the overall goal for views is that if
any view is theoretically updatable, it should be updatable in
practice. This includes views that have *Note `UNION': union. in their
definition.  Currently, not all views that are theoretically updatable
can be updated. The initial view implementation was deliberately written
this way to get usable, updatable views into MySQL as quickly as
possible. Many theoretically updatable views can be updated now, but
limitations still exist:

   * Updatable views with subqueries anywhere other than in the `WHERE'
     clause. Some views that have subqueries in the *Note `SELECT':
     select. list may be updatable.

   * You cannot use *Note `UPDATE': update. to update more than one
     underlying table of a view that is defined as a join.

   * You cannot use *Note `DELETE': delete. to update a view that is
     defined as a join.

There exists a shortcoming with the current implementation of views. If
a user is granted the basic privileges necessary to create a view (the
`CREATE VIEW' and `SELECT' privileges), that user will be unable to
call *Note `SHOW CREATE VIEW': show-create-view.  on that object unless
the user is also granted the `SHOW VIEW' privilege.

That shortcoming can lead to problems backing up a database with *Note
`mysqldump': mysqldump, which may fail due to insufficient privileges.
This problem is described in Bug #22062.

The workaround to the problem is for the administrator to manually
grant the `SHOW VIEW' privilege to users who are granted `CREATE VIEW',
since MySQL doesn't grant it implicitly when views are created.

Views do not have indexes, so index hints do not apply. Use of index
hints when selecting from a view is not permitted.

*Note `SHOW CREATE VIEW': show-create-view. displays view definitions
using an `AS ALIAS_NAME' clause for each column. If a column is created
from an expression, the default alias is the expression text, which can
be quite long. As of MySQL 5.0.52, aliases for column names in *Note
`CREATE VIEW': create-view. statements are checked against the maximum
column length of 64 characters (not the maximum alias length of 256
characters). As a result, views created from the output of *Note `SHOW
CREATE VIEW': show-create-view. fail if any column alias exceeds 64
characters. This can cause problems in the following circumstances for
views with too-long aliases:

   * View definitions fail to replicate to newer slaves that enforce
     the column-length restriction.

   * Dump files created with *Note `mysqldump': mysqldump. cannot be
     loaded into servers that enforce the column-length restriction.

A workaround for either problem is the modify each problematic view
definition to use aliases that provide shorter column names.  Then the
view will replicate properly, and can be dumped and reloaded without
causing an error. To modify the definition, drop and create the view
again with *Note `DROP VIEW': drop-view. and *Note `CREATE VIEW':
create-view, or replace the definition with *Note `CREATE OR REPLACE
VIEW': create-view.

For problems that occur when reloading view definitions in dump files,
another workaround is to edit the dump file to modify its *Note `CREATE
VIEW': create-view. statements. However, this does not change the
original view definitions, which may cause problems for subsequent dump
operations.


File: manual.info,  Node: xa-restrictions,  Next: charset-restrictions,  Prev: view-restrictions,  Up: restrictions

E.5 Restrictions on XA Transactions
===================================

XA transaction support is limited to the `InnoDB' storage engine.

For `external XA,' a MySQL server acts as a Resource Manager and client
programs act as Transaction Managers. For `Internal XA', storage
engines within a MySQL server act as RMs, and the server itself acts as
a TM. Internal XA support is limited by the capabilities of individual
storage engines. Internal XA is required for handling XA transactions
that involve more than one storage engine. The implementation of
internal XA requires that a storage engine support two-phase commit at
the table handler level, and currently this is true only for `InnoDB'.

For *Note `XA START': xa-statements, the `JOIN' and `RESUME' clauses
are not supported.

For *Note `XA END': xa-statements, the `SUSPEND [FOR MIGRATE]' clause
is not supported.

The requirement that the BQUAL part of the XID value be different for
each XA transaction within a global transaction is a limitation of the
current MySQL XA implementation. It is not part of the XA specification.

If an XA transaction has reached the `PREPARED' state and the MySQL
server is killed (for example, with *Note `kill -9': kill. on Unix) or
shuts down abnormally, the transaction can be continued after the
server restarts. However, if the client reconnects and commits the
transaction, the transaction will be absent from the binary log even
though it has been committed. This means the data and the binary log
have gone out of synchrony. An implication is that XA cannot be used
safely together with replication.

It is possible that the server will roll back a pending XA transaction,
even one that has reached the `PREPARED' state. This happens if a client
connection terminates and the server continues to run, or if clients
are connected and the server shuts down gracefully. (In the latter
case, the server marks each connection to be terminated, and then rolls
back the `PREPARED' XA transaction associated with it.) It should be
possible to commit or roll back a `PREPARED' XA transaction, but this
cannot be done without changes to the binary logging mechanism.


File: manual.info,  Node: charset-restrictions,  Next: limits,  Prev: xa-restrictions,  Up: restrictions

E.6 Restrictions on Character Sets
==================================

   * Identifiers are stored in `mysql' database tables (`user', `db',
     and so forth) using `utf8', but identifiers can contain only
     characters in the Basic Multilingual Plane (BMP).  Supplementary
     characters are not permitted in identifiers.

   * The `ucs2' character sets has the following restrictions:

        * It cannot be used as a client character set, which means that
          it does not work for `SET NAMES' or `SET CHARACTER SET'. (See
          *Note charset-connection::.)

        * It is currently not possible to use *Note `LOAD DATA INFILE':
          load-data. to load data files that use this character set.

        * `FULLTEXT' indexes cannot be created on a column that this
          character set. However, you can perform `IN BOOLEAN MODE'
          searches on the column without an index.

   * The `REGEXP' and `RLIKE' operators work in byte-wise fashion, so
     they are not multi-byte safe and may produce unexpected results
     with multi-byte character sets. In addition, these operators
     compare characters by their byte values and accented characters
     may not compare as equal even if a given collation treats them as
     equal.


File: manual.info,  Node: limits,  Prev: charset-restrictions,  Up: restrictions

E.7 Limits in MySQL
===================

* Menu:

* joins-limits::                 Limits of Joins
* database-count-limit::         Limits on Number of Databases and Tables
* table-size-limit::             Limits on Table Size
* column-count-limit::           Table Column-Count and Row-Size Limits
* limits-windows::               Windows Platform Limitations

This section lists current limits in MySQL 5.0.


File: manual.info,  Node: joins-limits,  Next: database-count-limit,  Prev: limits,  Up: limits

E.7.1 Limits of Joins
---------------------

The maximum number of tables that can be referenced in a single join is
61. This also applies to the number of tables that can be referenced in
the definition of a view.


File: manual.info,  Node: database-count-limit,  Next: table-size-limit,  Prev: joins-limits,  Up: limits

E.7.2 Limits on Number of Databases and Tables
----------------------------------------------

MySQL has no limit on the number of databases. The underlying file
system may have a limit on the number of directories.

MySQL has no limit on the number of databases. The underlying file
system may have a limit on the number of tables. Individual storage
engines may impose engine-specific constraints.  `InnoDB' permits up to
4 billion tables.


File: manual.info,  Node: table-size-limit,  Next: column-count-limit,  Prev: database-count-limit,  Up: limits

E.7.3 Limits on Table Size
--------------------------

The effective maximum table size for MySQL databases is usually
determined by operating system constraints on file sizes, not by MySQL
internal limits. The following table lists some examples of operating
system file-size limits. This is only a rough guide and is not intended
to be definitive. For the most up-to-date information, be sure to check
the documentation specific to your operating system.

Operating System       File-size Limit
Win32 w/ FAT/FAT32     2GB/4GB
Win32 w/ NTFS          2TB (possibly larger)
Linux 2.2-Intel 32-bit 2GB (LFS: 4GB)
Linux 2.4+             (using ext3 file system) 4TB
Solaris 9/10           16TB
MacOS X w/ HFS+        2TB
NetWare w/NSS file     8TB
system                 

Windows users, please note that FAT and VFAT (FAT32) are _not_
considered suitable for production use with MySQL. Use NTFS instead.

On Linux 2.2, you can get `MyISAM' tables larger than 2GB in size by
using the Large File Support (LFS) patch for the ext2 file system. Most
current Linux distributions are based on kernel 2.4 or higher and
include all the required LFS patches. On Linux 2.4, patches also exist
for ReiserFS to get support for big files (up to 2TB). With JFS and XFS,
petabyte and larger files are possible on Linux.

For a detailed overview about LFS in Linux, have a look at Andreas
Jaeger's `Large File Support in Linux' page at
`http://www.suse.de/~aj/linux_lfs.html'.

If you do encounter a full-table error, there are several reasons why
it might have occurred:

   * The disk might be full.

   * The `InnoDB' storage engine maintains `InnoDB' tables within a
     tablespace that can be created from several files. This enables a
     table to exceed the maximum individual file size. The tablespace
     can include raw disk partitions, which permits extremely large
     tables. The maximum tablespace size is 64TB.

     If you are using `InnoDB' tables and run out of room in the
     `InnoDB' tablespace. In this case, the solution is to extend the
     `InnoDB' tablespace. See *Note innodb-data-log-reconfiguration::.

   * You are using `MyISAM' tables on an operating system that supports
     files only up to 2GB in size and you have hit this limit for the
     data file or index file.

   * You are using a `MyISAM' table and the space required for the
     table exceeds what is permitted by the internal pointer size.
     `MyISAM' creates data and index table files to permit up to 4GB by
     default (256TB as of MySQL 5.0.6), but this limit can be changed up
     to the maximum permissible size of 65,536TB (256^7 - 1 bytes).

     If you need a `MyISAM' table that is larger than the default limit
     and your operating system supports large files, the *Note `CREATE
     TABLE': create-table.  statement supports `AVG_ROW_LENGTH' and
     `MAX_ROWS' options. See *Note create-table::. The server uses these
     options to determine how large a table to permit.

     If the pointer size is too small for an existing table, you can
     change the options with *Note `ALTER TABLE': alter-table. to
     increase a table's maximum permissible size. See *Note
     alter-table::.

          ALTER TABLE TBL_NAME MAX_ROWS=1000000000 AVG_ROW_LENGTH=NNN;

     You have to specify `AVG_ROW_LENGTH' only for tables with *Note
     `BLOB': blob. or *Note `TEXT': blob. columns; in this case, MySQL
     can't optimize the space required based only on the number of rows.

     To change the default size limit for `MyISAM' tables, set the
     `myisam_data_pointer_size', which sets the number of bytes used
     for internal row pointers. The value is used to set the pointer
     size for new tables if you do not specify the `MAX_ROWS' option.
     The value of `myisam_data_pointer_size' can be from 2 to 7. A
     value of 4 permits tables up to 4GB; a value of 6 permits tables
     up to 256TB.

     You can check the maximum data and index sizes by using this
     statement:

          SHOW TABLE STATUS FROM DB_NAME LIKE 'TBL_NAME';

     You also can use *Note `myisamchk -dv /path/to/table-index-file':
     myisamchk. See *Note show::, or *Note myisamchk::.

     Other ways to work around file-size limits for `MyISAM' tables are
     as follows:

        * If your large table is read only, you can use *Note
          `myisampack': myisampack. to compress it.  *Note
          `myisampack': myisampack. usually compresses a table by at
          least 50%, so you can have, in effect, much bigger tables.
          *Note `myisampack': myisampack. also can merge multiple
          tables into a single table. See *Note myisampack::.

        * MySQL includes a `MERGE' library that enables you to handle a
          collection of `MyISAM' tables that have identical structure
          as a single `MERGE' table.  See *Note merge-storage-engine::.

   * You are using the *Note `NDB': mysql-cluster. storage engine, in
     which case you need to increase the values for the `DataMemory' and
     `IndexMemory' configuration parameters in your `config.ini' file.
     See *Note mysql-cluster-params-ndbd::.

   * You are using the `MEMORY' (`HEAP') storage engine; in this case
     you need to increase the value of the `max_heap_table_size' system
     variable. See *Note server-system-variables::.


File: manual.info,  Node: column-count-limit,  Next: limits-windows,  Prev: table-size-limit,  Up: limits

E.7.4 Table Column-Count and Row-Size Limits
--------------------------------------------

There is a hard limit of 4096 columns per table, but the effective
maximum may be less for a given table. The exact limit depends on
several interacting factors.

   * Every table (regardless of storage engine) has a maximum row size
     of 65,535 bytes. Storage engines may place additional constraints
     on this limit, reducing the effective maximum row size.

     The maximum row size constrains the number (and possibly size) of
     columns because the total length of all columns cannot exceed this
     size. For example, `utf8' characters require up to three bytes per
     character, so for a *Note `CHAR(255) CHARACTER SET utf8': char.
     column, the server must allocate 255 x 3 = 765 bytes per value.
     Consequently, a table cannot contain more than 65,535 / 765 = 85
     such columns.

     Storage for variable-length columns includes length bytes, which
     are assessed against the row size. For example, a *Note
     `VARCHAR(255) CHARACTER SET utf8': char. column takes two bytes to
     store the length of the value, so each value can take up to 767
     bytes.

     *Note `BLOB': blob. and *Note `TEXT': blob. columns count from one
     to four plus eight bytes each toward the row-size limit because
     their contents are stored separately from the rest of the row.

     Declaring columns `NULL' can reduce the maximum number of columns
     permitted. For *Note `MyISAM': myisam-storage-engine. tables,
     `NULL' columns require additional space in the row to record
     whether their values are `NULL'. Each `NULL' column takes one bit
     extra, rounded up to the nearest byte. The maximum row length in
     bytes can be calculated as follows:

          row length = 1
                       + (SUM OF COLUMN LENGTHS)
                       + (NUMBER OF NULL COLUMNS + DELETE_FLAG + 7)/8
                       + (NUMBER OF VARIABLE-LENGTH COLUMNS)

     DELETE_FLAG is 1 for tables with static row format. Static tables
     use a bit in the row record for a flag that indicates whether the
     row has been deleted.  DELETE_FLAG is 0 for dynamic tables because
     the flag is stored in the dynamic row header.  For information
     about *Note `MyISAM': myisam-storage-engine.  table formats, see
     *Note myisam-table-formats::.

     These calculations do not apply for *Note `InnoDB':
     innodb-storage-engine. tables. Storage size is the same for `NULL'
     and `NOT NULL' columns.

     The following statement to create table `t1' succeeds because the
     columns require 32,765 + 2 bytes and 32,766 + 2 bytes, which falls
     within the maximum row size of 65,535 bytes:

          mysql> CREATE TABLE t1
              -> (c1 VARCHAR(32765) NOT NULL, c2 VARCHAR(32766) NOT NULL)
              -> ENGINE = MyISAM CHARACTER SET latin1;
          Query OK, 0 rows affected (0.02 sec)

     The following statement to create table `t2' fails because the
     columns are `NULL' and *Note `MyISAM': myisam-storage-engine.
     requires additional space that causes the row size to exceed
     65,535 bytes:

          mysql> CREATE TABLE t2
              -> (c1 VARCHAR(32765) NULL, c2 VARCHAR(32766) NULL)
              -> ENGINE = MyISAM CHARACTER SET latin1;
          ERROR 1118 (42000): Row size too large. The maximum row size for the
          used table type, not counting BLOBs, is 65535. You have to change some
          columns to TEXT or BLOBs

     The following statement to create table `t3' fails because
     although the column length is within the maximum length of 65,535
     bytes, two additional bytes are required to record the length,
     which causes the row size to exceed 65,535 bytes:

          mysql> CREATE TABLE t3
              -> (c1 VARCHAR(65535) NOT NULL)
              -> ENGINE = MyISAM CHARACTER SET latin1;
          ERROR 1118 (42000): Row size too large. The maximum row size for the
          used table type, not counting BLOBs, is 65535. You have to change some
          columns to TEXT or BLOBs

     Reducing the column length to 65,533 or less permits the statement
     to succeed.

   * Each table has an `.frm' file that contains the table definition.
     The server uses the following expression to check some of the
     table information stored in the file against an upper limit of
     64KB:

          if (info_length+(ulong) create_fields.elements*FCOMP+288+
              n_length+int_length+com_length > 65535L || int_count > 255)

     The portion of the information stored in the `.frm' file that is
     checked against the expression cannot grow beyond the 64KB limit,
     so if the table definition reaches this size, no more columns can
     be added.

     The relevant factors in the expression are:

        * `info_length' is space needed for `screens.' This is related
          to MySQL's Unireg heritage.

        * `create_fields.elements' is the number of columns.

        * `FCOMP' is 17.

        * `n_length' is the total length of all column names, including
          one byte per name as a separator.

        * `int_length' is related to the list of values for *Note
          `ENUM': enum. and *Note `SET': set. columns.

        * `com_length' is the total length of column and table comments.

     Thus, using long column names can reduce the maximum number of
     columns, as can the inclusion of *Note `ENUM': enum. or *Note
     `SET': set. columns, or use of column or table comments.

   * Individual storage engines might impose additional restrictions
     that limit table column count. Examples:

        * *Note `InnoDB': innodb-storage-engine. permits up to 1000
          columns.

        * *Note `InnoDB': innodb-storage-engine. restricts row size to
          something less than half a database page (approximately 8000
          bytes), not including *Note `VARBINARY': binary-varbinary,
          *Note `VARCHAR': char, *Note `BLOB': blob, or *Note `TEXT':
          blob. columns.

        * Different *Note `InnoDB': innodb-storage-engine. storage
          formats (`COMPRESSED', `REDUNDANT') use different amounts of
          page header and trailer data, which affects the amount of
          storage available for rows.


File: manual.info,  Node: limits-windows,  Prev: column-count-limit,  Up: limits

E.7.5 Windows Platform Limitations
----------------------------------

The following limitations apply to use of MySQL on the Windows platform:

   * *Number of file descriptors*

     The number of open file descriptors on Windows is limited to a
     maximum of 2048, which may limit the ability to open a large
     number of tables simultaneously. This limit is due not to Windows
     but to C runtime library compatibility functions used to open
     files on Windows that use the POSIX compatibility layer.

     This limitation will also cause problems if you try to set
     `open_files_limit' to a value greater than the 2048 file limit.

   * *Process memory*

     On Windows 32-bit platforms it is not possible by default to use
     more than 2GB of RAM within a single process, including MySQL.
     This is because the physical address limit on Windows 32-bit is
     4GB and the default setting within Windows is to split the virtual
     address space between kernel (2GB) and user/applications (2GB).

     Some versions of Windows have a boot time setting to enable larger
     applications by reducing the kernel application.  Alternatively,
     to use more than 2GB, use a 64-bit version of Windows.

   * *File system aliases*

     When using `MyISAM' tables, you cannot use aliases within Windows
     link to the data files on another volume and then link back to the
     main MySQL `datadir' location.

     This facility is often used to move the data and index files to a
     RAID or other fast solution, while retaining the main `.frm' files
     in the default data directory configured with the `datadir' option.

   * *Limited number of ports*

     Windows systems have about 4,000 ports available for client
     connections, and after a connection on a port closes, it takes two
     to four minutes before the port can be reused. In situations where
     clients connect to and disconnect from the server at a high rate,
     it is possible for all available ports to be used up before closed
     ports become available again. If this happens, the MySQL server
     appears to be unresponsive even though it is running. Note that
     ports may be used by other applications running on the machine as
     well, in which case the number of ports available to MySQL is
     lower.

     For more information about this problem, see
     `http://support.microsoft.com/default.aspx?scid=kb;en-us;196271'.

   * *Concurrent reads*

     MySQL depends on the `pread()' and `pwrite()' system calls to be
     able to mix *Note `INSERT': insert. and *Note `SELECT': select.
     Currently, we use mutexes to emulate `pread()' and `pwrite()'. We
     intend to replace the file level interface with a virtual
     interface in the future so that we can use the
     `readfile()'/`writefile()' interface to get more speed. The
     current implementation limits the number of open files that MySQL
     5.0 can use to 2,048, which means that you cannot run as many
     concurrent threads on Windows as on Unix.

     This problem is fixed in MySQL 5.5.

   * *Blocking read*

     MySQL uses a blocking read for each connection. That has the
     following implications if named-pipe connections are enabled:

        * A connection is not disconnected automatically after eight
          hours, as happens with the Unix version of MySQL.

        * If a connection hangs, it is not possible to break it without
          killing MySQL.

        * *Note `mysqladmin kill': mysqladmin. does not work on a
          sleeping connection.

        * *Note `mysqladmin shutdown': mysqladmin. cannot abort as long
          as there are sleeping connections.

     These problems are fixed in MySQL 5.1. (Bug #31621)

   * **Note `ALTER TABLE': alter-table.*

     While you are executing an *Note `ALTER TABLE': alter-table.
     statement, the table is locked from being used by other threads.
     This has to do with the fact that on Windows, you can't delete a
     file that is in use by another thread. In the future, we may find
     some way to work around this problem.

   * **Note `DROP TABLE': drop-table.*

     *Note `DROP TABLE': drop-table. on a table that is in use by a
     `MERGE' table does not work on Windows because the `MERGE' handler
     does the table mapping hidden from the upper layer of MySQL.
     Because Windows does not permit dropping files that are open, you
     first must flush all `MERGE' tables (with *Note `FLUSH TABLES':
     flush.) or drop the `MERGE' table before dropping the table.

   * *`DATA DIRECTORY' and `INDEX DIRECTORY'*

     The `DATA DIRECTORY' and `INDEX DIRECTORY' options for *Note
     `CREATE TABLE': create-table. are ignored on Windows, because
     MySQL does not support Windows symbolic links. These options also
     are ignored on systems that have a nonfunctional `realpath()' call.

   * **Note `DROP DATABASE': drop-database.*

     You cannot drop a database that is in use by another session.

   * *Case-insensitive names*

     File names are not case sensitive on Windows, so MySQL database
     and table names are also not case sensitive on Windows. The only
     restriction is that database and table names must be specified
     using the same case throughout a given statement. See *Note
     identifier-case-sensitivity::.

   * *Directory and file names*

     On Windows, MySQL Server supports only directory and file names
     that are compatible with the current ANSI code pages.  For
     example, the following Japanese directory name will not work in
     the Western locale (code page 1252):

          datadir="C:/私たちのプロジェクトのデータ"

     The same limitation applies to directory and file names referred
     to in SQL statements, such as the data file path name in *Note
     `LOAD DATA INFILE': load-data.

   * *The ``\'' path name separator character*

     Path name components in Windows are separated by the ``\''
     character, which is also the escape character in MySQL. If you are
     using *Note `LOAD DATA INFILE': load-data. or *Note `SELECT ...
     INTO OUTFILE': select-into, use Unix-style file names with ``/''
     characters:

          mysql> LOAD DATA INFILE 'C:/tmp/skr.txt' INTO TABLE skr;
          mysql> SELECT * INTO OUTFILE 'C:/tmp/skr.txt' FROM skr;

     Alternatively, you must double the ``\'' character:

          mysql> LOAD DATA INFILE 'C:\\tmp\\skr.txt' INTO TABLE skr;
          mysql> SELECT * INTO OUTFILE 'C:\\tmp\\skr.txt' FROM skr;

   * *Problems with pipes*

     Pipes do not work reliably from the Windows command-line prompt.
     If the pipe includes the character `^Z' / `CHAR(24)', Windows
     thinks that it has encountered end-of-file and aborts the program.

     This is mainly a problem when you try to apply a binary log as
     follows:

          shell> mysqlbinlog BINARY_LOG_FILE | mysql --user=root

     If you have a problem applying the log and suspect that it is
     because of a `^Z' / `CHAR(24)' character, you can use the
     following workaround:

          shell> mysqlbinlog BINARY_LOG_FILE --result-file=/tmp/bin.sql
          shell> mysql --user=root --execute "source /tmp/bin.sql"

     The latter command also can be used to reliably read in any SQL
     file that may contain binary data.

[index]
* Menu:

* ! (logical NOT):                       logical-operators.  (line   29)
* != (not equal):                        comparison-operators.
                                                             (line   91)
* ":                                     identifiers.        (line   18)
* %:                                     arithmetic-functions.
                                                             (line  118)
* % (modulo):                            mathematical-functions.
                                                             (line  303)
* % (wildcard character):                string-literals.    (line   77)
* & (bitwise AND):                       bit-functions.      (line   29)
* && (logical AND):                      logical-operators.  (line   51)
* () (parentheses):                      operator-precedence.
                                                             (line   49)
* (Control+Z) \Z <1>:                    load-data.          (line  419)
* (Control+Z) \Z:                        string-literals.    (line   75)
* * (multiplication):                    arithmetic-functions.
                                                             (line   83)
* + (addition):                          arithmetic-functions.
                                                             (line   55)
* - (subtraction):                       arithmetic-functions.
                                                             (line   62)
* - (unary minus):                       arithmetic-functions.
                                                             (line   69)
* -? option, MySQL Cluster programs:     mysql-cluster-program-options-common.
                                                             (line   45)
* -append option (ndb_restore):          mysql-cluster-programs-ndb-restore.
                                                             (line  318)
* -c option (MySQL Cluster programs):    mysql-cluster-program-options-common.
                                                             (line   56)
* -c option (MySQL Cluster):             mysql-cluster-program-options-common.
                                                             (line  109)
* -c option (ndb_mgmd) (OBSOLETE):       mysql-cluster-programs-ndb-mgmd.
                                                             (line   51)
* -character-sets-dir option, MySQL Cluster programs: mysql-cluster-program-options-common.
                                                             (line   95)
* -config-file option (ndb_mgmd):        mysql-cluster-programs-ndb-mgmd.
                                                             (line   51)
* -connect-string option (MySQL Cluster programs): mysql-cluster-program-options-common.
                                                             (line   56)
* -connect-string option (MySQL Cluster): mysql-cluster-program-options-common.
                                                             (line  109)
* -core-file option (MySQL Cluster):     mysql-cluster-program-options-common.
                                                             (line  118)
* -d option (ndb_mgmd):                  mysql-cluster-programs-ndb-mgmd.
                                                             (line   87)
* -daemon option (ndb_mgmd):             mysql-cluster-programs-ndb-mgmd.
                                                             (line   87)
* -debug option (MySQL Cluster):         mysql-cluster-program-options-common.
                                                             (line  142)
* -disable option prefix:                option-modifiers.   (line    6)
* -dont_ignore_systab_0 option (ndb_restore): mysql-cluster-programs-ndb-restore.
                                                             (line  179)
* -e option (ndb_mgm):                   mysql-cluster-programs-ndb-mgm.
                                                             (line   41)
* -enable option prefix:                 option-modifiers.   (line    6)
* -execute option (ndb_mgm):             mysql-cluster-programs-ndb-mgm.
                                                             (line   41)
* -f option (ndb_mgmd):                  mysql-cluster-programs-ndb-mgmd.
                                                             (line   51)
* -fields-enclosed-by option (ndb_restore): mysql-cluster-programs-ndb-restore.
                                                             (line  244)
* -fields-optionally-enclosed-by option (ndb_restore): mysql-cluster-programs-ndb-restore.
                                                             (line  259)
* -fields-terminated-by option (ndb_restore): mysql-cluster-programs-ndb-restore.
                                                             (line  276)
* -help option, MySQL Cluster programs:  mysql-cluster-program-options-common.
                                                             (line   45)
* -hex option (ndb_restore):             mysql-cluster-programs-ndb-restore.
                                                             (line  292)
* -initial option (ndbd):                mysql-cluster-programs-ndbd.
                                                             (line   82)
* -initial-start option (ndbd):          mysql-cluster-programs-ndbd.
                                                             (line  136)
* -interactive option (ndb_mgmd):        mysql-cluster-programs-ndb-mgmd.
                                                             (line  102)
* -loose option prefix:                  option-modifiers.   (line    6)
* -maximum option prefix:                option-modifiers.   (line    6)
* -n option (ndbd):                      mysql-cluster-programs-ndbd.
                                                             (line  235)
* -ndb-connectstring option (MySQL Cluster programs): mysql-cluster-program-options-common.
                                                             (line   56)
* -ndb-mgmd-host option (MySQL Cluster programs): mysql-cluster-program-options-common.
                                                             (line   77)
* -ndb-mgmd-host option (MySQL Cluster): mysql-cluster-program-options-mysqld.
                                                             (line   39)
* -ndb-nodeid option (MySQL Cluster):    mysql-cluster-program-options-common.
                                                             (line  157)
* -ndb-optimized-node-selection option (MySQL Cluster): mysql-cluster-program-options-common.
                                                             (line  174)
* -ndb-shm option (MySQL Cluster programs; OBSOLETE): mysql-cluster-program-options-common.
                                                             (line  202)
* -no-nodeid-checks option (ndb_mgmd):   mysql-cluster-programs-ndb-mgmd.
                                                             (line   38)
* -nodaemon option (ndb_mgmd):           mysql-cluster-programs-ndb-mgmd.
                                                             (line  119)
* -nodaemon option (ndbd):               mysql-cluster-programs-ndbd.
                                                             (line  199)
* -nostart option (ndbd):                mysql-cluster-programs-ndbd.
                                                             (line  235)
* -nowait-nodes option (ndbd):           mysql-cluster-programs-ndbd.
                                                             (line  162)
* -p option:                             password-security-user.
                                                             (line   17)
* -P option (ndb_mgmd):                  mysql-cluster-programs-ndb-mgmd.
                                                             (line  138)
* -parallelism option (ndb_restore):     mysql-cluster-programs-ndb-restore.
                                                             (line  188)
* -password option:                      password-security-user.
                                                             (line   17)
* -print option (ndb_restore):           mysql-cluster-programs-ndb-restore.
                                                             (line  212)
* -print-full-config option (ndb_mgmd):  mysql-cluster-programs-ndb-mgmd.
                                                             (line  138)
* -print_data option (ndb_restore):      mysql-cluster-programs-ndb-restore.
                                                             (line  218)
* -print_log option (ndb_restore):       mysql-cluster-programs-ndb-restore.
                                                             (line  207)
* -print_metadata option (ndb_restore):  mysql-cluster-programs-ndb-restore.
                                                             (line  202)
* -restore_data option (ndb_restore):    mysql-cluster-programs-ndb-restore.
                                                             (line  194)
* -restore_meta option (ndb_restore):    mysql-cluster-programs-ndb-restore.
                                                             (line  198)
* -skip option prefix:                   option-modifiers.   (line    6)
* -tab option (ndb_restore):             mysql-cluster-programs-ndb-restore.
                                                             (line  231)
* -usage option, MySQL Cluster programs: mysql-cluster-program-options-common.
                                                             (line   45)
* -V option (MySQL Cluster):             mysql-cluster-program-options-common.
                                                             (line  187)
* -verbose option (ndb_restore):         mysql-cluster-programs-ndb-restore.
                                                             (line  334)
* -version option (MySQL Cluster):       mysql-cluster-program-options-common.
                                                             (line  187)
* .my.cnf file <1>:                      multiple-server-clients.
                                                             (line   34)
* .my.cnf file <2>:                      access-denied.      (line  101)
* .my.cnf file <3>:                      password-security-user.
                                                             (line   56)
* .my.cnf file <4>:                      option-files.       (line   11)
* .my.cnf file:                          connecting.         (line  220)
* .mysql_history file <1>:               password-security-user.
                                                             (line   88)
* .mysql_history file:                   mysql-history-file. (line    6)
* .pid (process ID) file:                myisam-maintenance-schedule.
                                                             (line   17)
* / (division):                          arithmetic-functions.
                                                             (line   92)
* /etc/passwd <1>:                       select-into.        (line   24)
* /etc/passwd:                           security-against-attack.
                                                             (line  106)
* := (assignment operator):              assignment-operators.
                                                             (line   15)
* := (assignment):                       user-variables.     (line    6)
* < (less than):                         comparison-operators.
                                                             (line  109)
* <<:                                    calculating-days.   (line    6)
* << (left shift):                       bit-functions.      (line   51)
* <= (less than or equal):               comparison-operators.
                                                             (line  102)
* <=> (equal to):                        comparison-operators.
                                                             (line   79)
* <> (not equal):                        comparison-operators.
                                                             (line   91)
* = (assignment operator):               assignment-operators.
                                                             (line   70)
* = (assignment):                        user-variables.     (line    6)
* = (equal):                             comparison-operators.
                                                             (line   64)
* > (greater than):                      comparison-operators.
                                                             (line  123)
* >= (greater than or equal):            comparison-operators.
                                                             (line  116)
* >> (right shift):                      bit-functions.      (line   63)
* [api] (MySQL Cluster):                 mysql-cluster-params-api.
                                                             (line    6)
* [computer] (MySQL Cluster):            mysql-cluster-params-other.
                                                             (line    6)
* [mgm] (MySQL Cluster):                 mysql-cluster-params-mgmd.
                                                             (line    6)
* [mysqld] (MySQL Cluster):              mysql-cluster-params-api.
                                                             (line    6)
* [ndb_mgmd] (MySQL Cluster):            mysql-cluster-params-mgmd.
                                                             (line    6)
* [ndbd default] (MySQL Cluster):        mysql-cluster-params-ndbd.
                                                             (line    6)
* [ndbd] (MySQL Cluster):                mysql-cluster-params-ndbd.
                                                             (line    6)
* [sci] (MySQL Cluster):                 mysql-cluster-params-other.
                                                             (line    6)
* [shm] (MySQL Cluster):                 mysql-cluster-params-other.
                                                             (line    6)
* [tcp] (MySQL Cluster):                 mysql-cluster-params-other.
                                                             (line    6)
* \" (double quote):                     string-literals.    (line   70)
* \' (single quote):                     string-literals.    (line   69)
* \. (mysql client command) <1>:         batch-commands.     (line    6)
* \. (mysql client command):             batch-mode.         (line   90)
* \0 (ASCII NUL) <1>:                    load-data.          (line  414)
* \0 (ASCII NUL):                        string-literals.    (line   68)
* \\ (escape):                           string-literals.    (line   76)
* \b (backspace) <1>:                    load-data.          (line  415)
* \b (backspace):                        string-literals.    (line   71)
* \n (linefeed) <1>:                     load-data.          (line  416)
* \n (linefeed):                         string-literals.    (line   72)
* \n (newline) <1>:                      load-data.          (line  416)
* \n (newline):                          string-literals.    (line   72)
* \N (NULL):                             load-data.          (line  420)
* \r (carriage return) <1>:              load-data.          (line  417)
* \r (carriage return):                  string-literals.    (line   73)
* \t (tab) <1>:                          load-data.          (line  418)
* \t (tab):                              string-literals.    (line   74)
* \Z (Control+Z) ASCII 26 <1>:           load-data.          (line  419)
* \Z (Control+Z) ASCII 26:               string-literals.    (line   75)
* ^ (bitwise XOR):                       bit-functions.      (line   38)
* _ (wildcard character):                string-literals.    (line   78)
* _rowid:                                create-table.       (line  307)
* `:                                     identifiers.        (line   18)
* abort-slave-event-count option, mysqld: replication-options-slave.
                                                             (line  122)
* aborted clients:                       communication-errors.
                                                             (line    6)
* aborted connection:                    communication-errors.
                                                             (line    6)
* ABS():                                 mathematical-functions.
                                                             (line   54)
* access control:                        connection-access.  (line    6)
* access denied errors:                  error-access-denied.
                                                             (line    6)
* access privileges:                     privilege-system.   (line   16)
* account names:                         account-names.      (line    6)
* account privileges, adding:            adding-users.       (line    6)
* accounts, anonymous user:              default-privileges. (line    6)
* accounts, root:                        default-privileges. (line    6)
* ACID <1>:                              innodb-storage-engine.
                                                             (line   23)
* ACID:                                  ansi-diff-transactions.
                                                             (line    6)
* ACLs:                                  privilege-system.   (line   16)
* ACOS():                                mathematical-functions.
                                                             (line   66)
* Active Server Pages (ASP):             connector-odbc-usagenotes-apptips-microsoft-asp.
                                                             (line    6)
* ActiveState Perl:                      activestate-perl.   (line    6)
* add-drop-database option, mysqldump:   mysqldump.          (line  334)
* add-drop-table option, mysqldump:      mysqldump.          (line  343)
* add-locks option, mysqldump:           mysqldump.          (line  348)
* ADDDATE():                             date-and-time-functions.
                                                             (line  133)
* adding, character sets:                adding-character-set.
                                                             (line   12)
* adding, native functions:              adding-native-function.
                                                             (line    6)
* adding, new account privileges:        adding-users.       (line    6)
* adding, new functions:                 adding-functions.   (line   12)
* adding, new user privileges:           adding-users.       (line    6)
* adding, new users <1>:                 unix-postinstallation.
                                                             (line  363)
* adding, new users:                     installing-source-distribution.
                                                             (line  198)
* adding, procedures:                    adding-procedures.  (line   11)
* adding, user-defined functions:        adding-udf.         (line   15)
* addition (+):                          arithmetic-functions.
                                                             (line   55)
* ADDTIME():                             date-and-time-functions.
                                                             (line  151)
* addtodest option, mysqlhotcopy:        mysqlhotcopy.       (line   84)
* administration of MySQL Cluster:       mysql-cluster-programs-ndb-mgm.
                                                             (line    6)
* administration, server:                mysqladmin.         (line    6)
* administrative programs:               programs-overview.  (line  167)
* AES_DECRYPT():                         encryption-functions.
                                                             (line   91)
* AES_ENCRYPT():                         encryption-functions.
                                                             (line   97)
* After create, thread state:            general-thread-states.
                                                             (line   11)
* age, calculating:                      date-calculations.  (line    6)
* alias names, case sensitivity:         identifier-case-sensitivity.
                                                             (line    6)
* aliases, for expressions:              group-by-hidden-columns.
                                                             (line   80)
* aliases, for tables:                   select.             (line  160)
* aliases, in GROUP BY clauses:          group-by-hidden-columns.
                                                             (line   80)
* aliases, names:                        identifiers.        (line   12)
* aliases, on expressions:               select.             (line  106)
* ALL <1>:                               all-subqueries.     (line    6)
* ALL:                                   select.             (line  357)
* ALL join type, optimizer:              explain-output.     (line  333)
* all-databases option, mysqlcheck:      mysqlcheck.         (line  181)
* all-databases option, mysqldump:       mysqldump.          (line  355)
* all-in-1 option, mysqlcheck:           mysqlcheck.         (line  187)
* allocating local table, thread state:  delayed-insert-thread-states.
                                                             (line   17)
* allow-keywords option, mysqldump:      mysqldump.          (line  361)
* allow-suspicious-udfs option, mysqld <1>: privileges-options.
                                                             (line   41)
* allow-suspicious-udfs option, mysqld:  server-options.     (line   81)
* ALLOW_INVALID_DATES SQL mode:          server-sql-mode.    (line   75)
* allowold option, mysqlhotcopy:         mysqlhotcopy.       (line   89)
* ALTER COLUMN:                          alter-table.        (line  241)
* ALTER DATABASE:                        alter-database.     (line    6)
* ALTER FUNCTION:                        alter-function.     (line    6)
* ALTER PROCEDURE:                       alter-procedure.    (line    6)
* ALTER SCHEMA:                          alter-database.     (line    6)
* ALTER TABLE <1>:                       alter-table-problems.
                                                             (line    6)
* ALTER TABLE:                           alter-table.        (line   10)
* ALTER VIEW:                            alter-view.         (line    6)
* altering, database:                    alter-database.     (line    6)
* altering, schema:                      alter-database.     (line    6)
* analyze option, myisamchk:             myisamchk-other-options.
                                                             (line    9)
* analyze option, mysqlcheck:            mysqlcheck.         (line  193)
* ANALYZE TABLE:                         analyze-table.      (line    6)
* Analyzing, thread state:               general-thread-states.
                                                             (line   18)
* AND, bitwise:                          bit-functions.      (line   29)
* AND, logical:                          logical-operators.  (line   51)
* angel-pid-file option, mysqlmanager:   instance-manager-command-options.
                                                             (line   28)
* anonymous user <1>:                    request-access.     (line   26)
* anonymous user <2>:                    connection-access.  (line   25)
* anonymous user:                        default-privileges. (line    6)
* ANSI mode, running:                    ansi-mode.          (line    6)
* ansi option, mysqld:                   server-options.     (line  102)
* ANSI SQL mode:                         server-sql-mode.    (line   43)
* ANSI_QUOTES SQL mode:                  server-sql-mode.    (line   95)
* answering questions, etiquette:        mailing-list-use.   (line    6)
* ANY:                                   any-in-some-subqueries.
                                                             (line    6)
* Apache:                                apache.             (line    6)
* API node (MySQL Cluster), defined:     mysql-cluster-basics.
                                                             (line    6)
* API nodes:                             mysql-cluster-programs-mysqld.
                                                             (line    6)
* API's, list of:                        packages.           (line    6)
* APIs:                                  connectors-apis.    (line   23)
* APIs, Perl:                            apis-perl.          (line    6)
* approximate-value literals:            precision-math.     (line   14)
* ArbitrationDelay <1>:                  mysql-cluster-api-definition.
                                                             (line  127)
* ArbitrationDelay:                      mysql-cluster-mgm-definition.
                                                             (line  191)
* ArbitrationRank <1>:                   mysql-cluster-api-definition.
                                                             (line  106)
* ArbitrationRank:                       mysql-cluster-mgm-definition.
                                                             (line  160)
* ArbitrationTimeout:                    mysql-cluster-ndbd-definition.
                                                             (line 1666)
* arbitrator:                            faqs-mysql-cluster. (line    6)
* ARCHIVE storage engine <1>:            archive-storage-engine.
                                                             (line    6)
* ARCHIVE storage engine:                storage-engines.    (line   19)
* Area() <1>:                            multipolygon-property-functions.
                                                             (line    8)
* Area():                                polygon-property-functions.
                                                             (line    8)
* argument processing:                   udf-arguments.      (line    6)
* arithmetic expressions:                arithmetic-functions.
                                                             (line   55)
* arithmetic functions:                  bit-functions.      (line    6)
* AS <1>:                                join.               (line    6)
* AS:                                    select.             (line  134)
* AS/400:                                i5os-installation.  (line    6)
* AsBinary():                            functions-to-convert-geometries-between-formats.
                                                             (line    9)
* ASCII():                               string-functions.   (line  103)
* ASIN():                                mathematical-functions.
                                                             (line   78)
* assignment operator, :=:               assignment-operators.
                                                             (line   15)
* assignment operator, =:                assignment-operators.
                                                             (line   70)
* assignment operators:                  assignment-operators.
                                                             (line    6)
* AsText():                              functions-to-convert-geometries-between-formats.
                                                             (line   16)
* ATAN():                                mathematical-functions.
                                                             (line  101)
* ATAN2():                               mathematical-functions.
                                                             (line  111)
* attackers, security against:           security-against-attack.
                                                             (line    6)
* AUTO-INCREMENT, ODBC:                  connector-odbc-usagenotes-functionality-last-insert-id.
                                                             (line    6)
* auto-rehash option, mysql:             mysql-command-options.
                                                             (line  151)
* auto-repair option, mysqlcheck:        mysqlcheck.         (line  197)
* AUTO_INCREMENT <1>:                    numeric-types.      (line   15)
* AUTO_INCREMENT:                        example-auto-increment.
                                                             (line    6)
* AUTO_INCREMENT, and NULL values:       problems-with-null. (line   71)
* AUTO_INCREMENT, and replication:       replication-features-auto-increment.
                                                             (line    6)
* auto_increment_increment system variable: replication-options-master.
                                                             (line   21)
* auto_increment_offset system variable: replication-options-master.
                                                             (line  224)
* autoclose option, mysqld_safe:         mysqld-safe.        (line  133)
* autocommit session variable:           server-system-variables.
                                                             (line  502)
* automatic_sp_privileges system variable: server-system-variables.
                                                             (line  543)
* AVG():                                 group-by-functions. (line   60)
* AVG(DISTINCT):                         group-by-functions. (line   60)
* back_log system variable:              server-system-variables.
                                                             (line  573)
* backslash, escape character:           string-literals.    (line    6)
* backspace (\b) <1>:                    load-data.          (line  415)
* backspace (\b):                        string-literals.    (line   71)
* backup identifiers, native backup and restore: mysql-cluster-backup-using-management-client.
                                                             (line   75)
* backup option, myisamchk:              myisamchk-repair-options.
                                                             (line   10)
* backup option, myisampack:             myisampack.         (line   51)
* BACKUP TABLE:                          backup-table.       (line    6)
* BackupDataBufferSize:                  mysql-cluster-backup-configuration.
                                                             (line    8)
* BackupDataBufferSize (MySQL Cluster configuration parameter): mysql-cluster-ndbd-definition.
                                                             (line 1993)
* BackupDataDir:                         mysql-cluster-ndbd-definition.
                                                             (line  262)
* BackupLogBufferSize <1>:               mysql-cluster-backup-configuration.
                                                             (line   13)
* BackupLogBufferSize:                   mysql-cluster-ndbd-definition.
                                                             (line 2017)
* BackupMaxWriteSize <1>:                mysql-cluster-backup-configuration.
                                                             (line   29)
* BackupMaxWriteSize:                    mysql-cluster-ndbd-definition.
                                                             (line 2092)
* BackupMemory <1>:                      mysql-cluster-backup-configuration.
                                                             (line   18)
* BackupMemory:                          mysql-cluster-ndbd-definition.
                                                             (line 2052)
* backups:                               backup-and-recovery.
                                                             (line   15)
* backups, database:                     backup-table.       (line    6)
* backups, databases and tables <1>:     mysqlhotcopy.       (line    6)
* backups, databases and tables:         mysqldump.          (line    6)
* backups, in MySQL Cluster <1>:         mysql-cluster-backup-configuration.
                                                             (line    6)
* backups, in MySQL Cluster <2>:         mysql-cluster-backup-using-management-client.
                                                             (line    6)
* backups, in MySQL Cluster <3>:         mysql-cluster-backup-concepts.
                                                             (line    6)
* backups, in MySQL Cluster <4>:         mysql-cluster-backup.
                                                             (line   13)
* backups, in MySQL Cluster:             mysql-cluster-programs-ndb-restore.
                                                             (line    6)
* backups, InnoDB:                       innodb-backup.      (line   12)
* backups, troubleshooting, in MySQL Cluster: mysql-cluster-backup-troubleshooting.
                                                             (line    6)
* backups, with mysqldump:               using-mysqldump.    (line   14)
* BackupWriteSize <1>:                   mysql-cluster-backup-configuration.
                                                             (line   24)
* BackupWriteSize:                       mysql-cluster-ndbd-definition.
                                                             (line 2075)
* basedir option, mysql.server:          mysql-server.       (line   36)
* basedir option, mysql_install_db:      mysql-install-db.   (line   45)
* basedir option, mysql_upgrade:         mysql-upgrade.      (line  103)
* basedir option, mysqld:                server-options.     (line  114)
* basedir option, mysqld_safe:           mysqld-safe.        (line  145)
* basedir system variable:               server-system-variables.
                                                             (line  609)
* batch mode:                            batch-mode.         (line    6)
* batch option, mysql:                   mysql-command-options.
                                                             (line  165)
* batch SQL files:                       mysql.              (line   15)
* BatchByteSize:                         mysql-cluster-api-definition.
                                                             (line  144)
* BatchSize:                             mysql-cluster-api-definition.
                                                             (line  164)
* BatchSizePerLocalScan:                 mysql-cluster-ndbd-definition.
                                                             (line  817)
* Bazaar tree:                           installing-development-tree.
                                                             (line    6)
* BDB storage engine <1>:                bdb-storage-engine. (line   15)
* BDB storage engine:                    storage-engines.    (line   19)
* BDB tables:                            ansi-diff-transactions.
                                                             (line    6)
* bdb-home option, mysqld:               bdb-start.          (line   39)
* bdb-lock-detect option, mysqld:        bdb-start.          (line   44)
* bdb-logdir option, mysqld:             bdb-start.          (line   49)
* bdb-no-recover option, mysqld:         bdb-start.          (line   53)
* bdb-no-sync option, mysqld:            bdb-start.          (line   57)
* bdb-shared-data option, mysqld:        bdb-start.          (line   63)
* bdb-tmpdir option, mysqld:             bdb-start.          (line   68)
* bdb_cache_size system variable:        server-system-variables.
                                                             (line  631)
* bdb_home system variable:              server-system-variables.
                                                             (line  654)
* bdb_log_buffer_size system variable:   server-system-variables.
                                                             (line  674)
* bdb_logdir system variable:            server-system-variables.
                                                             (line  698)
* bdb_max_lock system variable:          server-system-variables.
                                                             (line  718)
* bdb_shared_data system variable:       server-system-variables.
                                                             (line  744)
* bdb_tmpdir system variable:            server-system-variables.
                                                             (line  760)
* BdMPolyFromText():                     gis-wkt-functions.  (line   59)
* BdMPolyFromWKB():                      gis-wkb-functions.  (line   61)
* BdPolyFromText():                      gis-wkt-functions.  (line   65)
* BdPolyFromWKB():                       gis-wkb-functions.  (line   67)
* BEGIN <1>:                             begin-end.          (line    6)
* BEGIN:                                 commit.             (line    6)
* BEGIN, labels:                         statement-labels.   (line    6)
* BEGIN, XA transactions:                xa-statements.      (line    6)
* benchmark suite:                       mysql-benchmarks.   (line    6)
* BENCHMARK():                           information-functions.
                                                             (line   33)
* benchmarks:                            custom-benchmarks.  (line    6)
* BerkeleyDB storage engine <1>:         bdb-storage-engine. (line   15)
* BerkeleyDB storage engine:             storage-engines.    (line   19)
* BETWEEN ... AND:                       comparison-operators.
                                                             (line  199)
* big-tables option, mysqld:             server-options.     (line  135)
* big5:                                  faqs-cjk.           (line    6)
* big_tables session variable:           server-system-variables.
                                                             (line  779)
* BIGINT data type:                      numeric-type-overview.
                                                             (line  130)
* BIN():                                 string-functions.   (line  118)
* BINARY:                                cast-functions.     (line   13)
* BINARY data type <1>:                  binary-varbinary.   (line    6)
* BINARY data type:                      string-type-overview.
                                                             (line  187)
* binary distributions:                  mysql-binaries.     (line    6)
* binary distributions, installing:      binary-installation.
                                                             (line    6)
* binary distributions, on Linux:        binary-notes-linux. (line    6)
* binary log:                            binary-log.         (line    6)
* binary log, event groups:              set-global-sql-slave-skip-counter.
                                                             (line    6)
* binary logging, and MySQL Cluster:     mysql-cluster-limitations-exclusive-to-cluster.
                                                             (line   50)
* bind-address option, mysqld:           server-options.     (line  158)
* bind-address option, mysqlmanager:     instance-manager-command-options.
                                                             (line   42)
* Binlog Dump, thread command:           thread-commands.    (line    8)
* binlog-do-db option, mysqld:           replication-options-binary-log.
                                                             (line  133)
* binlog-ignore-db option, mysqld:       replication-options-binary-log.
                                                             (line  197)
* binlog_cache_size system variable:     server-system-variables.
                                                             (line  794)
* BIT data type:                         numeric-type-overview.
                                                             (line   35)
* BIT_AND():                             group-by-functions. (line   72)
* BIT_COUNT:                             calculating-days.   (line    6)
* BIT_COUNT():                           bit-functions.      (line   84)
* bit_functions, example:                calculating-days.   (line    6)
* BIT_LENGTH():                          string-functions.   (line  127)
* BIT_OR:                                calculating-days.   (line    6)
* BIT_OR():                              group-by-functions. (line   81)
* BIT_XOR():                             group-by-functions. (line   88)
* BLACKHOLE storage engine <1>:          blackhole-storage-engine.
                                                             (line    6)
* BLACKHOLE storage engine:              storage-engines.    (line   19)
* BLOB columns, default values:          blob.               (line   63)
* BLOB columns, indexing <1>:            create-table.       (line  359)
* BLOB columns, indexing:                column-indexes.     (line   15)
* BLOB data type <1>:                    blob.               (line    6)
* BLOB data type:                        string-type-overview.
                                                             (line  217)
* BLOB, inserting binary data:           string-literals.    (line  141)
* BLOB, size:                            storage-requirements.
                                                             (line  188)
* Block Nested-Loop join algorithm:      nested-loop-joins.  (line    6)
* block-search option, myisamchk:        myisamchk-other-options.
                                                             (line   18)
* BOOL data type:                        numeric-type-overview.
                                                             (line   50)
* BOOLEAN data type:                     numeric-type-overview.
                                                             (line   50)
* boolean options:                       option-modifiers.   (line    6)
* bootstrap option, mysqld:              server-options.     (line  183)
* Borland Builder 4:                     connector-odbc-usagenotes-apptips-borland-builder.
                                                             (line    6)
* Boundary():                            general-geometry-property-functions.
                                                             (line   70)
* brackets, square:                      data-types.         (line   41)
* brief option, mysqlaccess:             mysqlaccess.        (line   71)
* Buffer pool, InnoDB:                   innodb-buffer-pool. (line    6)
* buffer sizes, client:                  connectors-apis.    (line   23)
* buffer sizes, mysqld server:           server-parameters.  (line    6)
* Buffer():                              spatial-operators.  (line   11)
* bug reports, criteria for:             bug-reports.        (line    6)
* bugs database:                         bug-reports.        (line    6)
* bugs, known:                           bugs.               (line    6)
* bugs, MySQL Cluster, reporting:        mysql-cluster-programs-ndb-error-reporter.
                                                             (line    6)
* bugs, reporting:                       bug-reports.        (line    6)
* bugs.mysql.com:                        bug-reports.        (line    6)
* building, client programs:             building-clients.   (line   11)
* bulk_insert_buffer_size system variable: server-system-variables.
                                                             (line  834)
* C API, data types:                     c.                  (line   25)
* C API, functions:                      c-api-function-overview.
                                                             (line    6)
* C API, linking problems:               c-api-linking-problems.
                                                             (line    6)
* C prepared statement API, functions <1>: c-api-prepared-statement-function-overview.
                                                             (line    6)
* C prepared statement API, functions:   c-api-prepared-statement-type-conversions.
                                                             (line    6)
* C prepared statement API, type codes:  c-api-prepared-statement-type-codes.
                                                             (line    6)
* C++ Builder:                           connector-odbc-usagenotes-apptips-borland-cppbuilder.
                                                             (line    6)
* C++ compiler cannot create executables: compilation-problems.
                                                             (line   62)
* C++ compiler, gcc:                     source-configuration-options.
                                                             (line  350)
* C:\my.cnf file:                        multiple-server-clients.
                                                             (line   34)
* CACHE INDEX:                           cache-index.        (line    6)
* caches, clearing:                      flush.              (line    6)
* calculating, dates:                    date-calculations.  (line    6)
* calendar:                              mysql-calendar.     (line    6)
* CALL:                                  call.               (line    6)
* calling sequences for aggregate functions, UDF: udf-aggr-calling.
                                                             (line    6)
* calling sequences for simple functions, UDF: udf-calling.  (line    6)
* can't create/write to file:            cannot-create.      (line    6)
* carriage return (\r) <1>:              load-data.          (line  417)
* carriage return (\r):                  string-literals.    (line   73)
* CASE <1>:                              case-statement.     (line    6)
* CASE:                                  control-flow-functions.
                                                             (line   14)
* case sensitivity, in access checking:  grant-table-structure.
                                                             (line  240)
* case sensitivity, in identifiers:      identifier-case-sensitivity.
                                                             (line    6)
* case sensitivity, in names:            identifier-case-sensitivity.
                                                             (line    6)
* case sensitivity, in searches:         case-sensitivity.   (line    6)
* case sensitivity, in string comparisons: string-comparison-functions.
                                                             (line   17)
* case sensitivity, of replication filtering options: replication-rules.
                                                             (line   56)
* case-sensitivity, of database names:   extensions-to-ansi. (line   38)
* case-sensitivity, of table names:      extensions-to-ansi. (line   38)
* CAST:                                  cast-functions.     (line   39)
* cast functions:                        cast-functions.     (line    6)
* cast operators:                        cast-functions.     (line    6)
* casts <1>:                             cast-functions.     (line    6)
* casts <2>:                             comparison-operators.
                                                             (line   38)
* casts:                                 type-conversion.    (line    6)
* CC environment variable <1>:           environment-variables.
                                                             (line   18)
* CC environment variable <2>:           compilation-problems.
                                                             (line   88)
* CC environment variable:               source-configuration-options.
                                                             (line  350)
* cc1plus problems:                      compilation-problems.
                                                             (line   37)
* CEIL():                                mathematical-functions.
                                                             (line  123)
* CEILING():                             mathematical-functions.
                                                             (line  127)
* Centroid():                            multipolygon-property-functions.
                                                             (line   26)
* CFLAGS environment variable <1>:       environment-variables.
                                                             (line   18)
* CFLAGS environment variable <2>:       compilation-problems.
                                                             (line   88)
* CFLAGS environment variable:           source-configuration-options.
                                                             (line  364)
* cflags option, mysql_config:           mysql-config.       (line   11)
* CHANGE MASTER TO:                      change-master-to.   (line    6)
* Change user, thread command:           thread-commands.    (line   13)
* ChangeLog <1>:                         news-5-0-x.         (line  115)
* ChangeLog:                             news.               (line   17)
* changes to privileges:                 privilege-changes.  (line    6)
* changes, Cluster:                      mysql-cluster-change-history.
                                                             (line   26)
* changes, log <1>:                      news-5-0-x.         (line  115)
* changes, log:                          news.               (line   17)
* changes, MySQL 5.0:                    news-5-0-x.         (line  115)
* changes, MySQL Community Server <1>:   news-5-0-x.         (line  115)
* changes, MySQL Community Server:       news.               (line   17)
* changes, MySQL Enterprise <1>:         news-5-0-x.         (line  115)
* changes, MySQL Enterprise:             news.               (line   17)
* Changing master, thread state:         slave-connection-thread-states.
                                                             (line    9)
* changing socket location <1>:          problems-with-mysql-sock.
                                                             (line   26)
* changing socket location <2>:          automatic-start.    (line  131)
* changing socket location:              source-configuration-options.
                                                             (line  330)
* changing, column:                      alter-table.        (line  241)
* changing, field:                       alter-table.        (line  241)
* changing, table <1>:                   alter-table-problems.
                                                             (line    6)
* changing, table:                       alter-table.        (line   10)
* CHAR data type <1>:                    string-types.       (line   14)
* CHAR data type:                        string-type-overview.
                                                             (line  100)
* CHAR VARYING data type:                string-type-overview.
                                                             (line  147)
* CHAR():                                string-functions.   (line  134)
* CHAR_LENGTH():                         string-functions.   (line  182)
* CHARACTER data type:                   string-type-overview.
                                                             (line  100)
* character set repertoire:              charset-repertoire. (line    6)
* Character sets:                        charset.            (line   22)
* character sets:                        source-configuration-options.
                                                             (line  400)
* character sets, adding:                adding-character-set.
                                                             (line   12)
* character sets, and replication:       replication-features-charset.
                                                             (line    6)
* character sets, restrictions:          charset-restrictions.
                                                             (line    6)
* CHARACTER VARYING data type:           string-type-overview.
                                                             (line  147)
* character-set-client-handshake option, mysqld: server-options.
                                                             (line  218)
* character-set-filesystem option, mysqld: server-options.   (line  235)
* character-set-server option, mysqld:   server-options.     (line  257)
* character-sets-dir option, myisamchk:  myisamchk-repair-options.
                                                             (line   14)
* character-sets-dir option, myisampack: myisampack.         (line   56)
* character-sets-dir option, mysql:      mysql-command-options.
                                                             (line  175)
* character-sets-dir option, mysqladmin: mysqladmin.         (line  290)
* character-sets-dir option, mysqlbinlog: mysqlbinlog.       (line  146)
* character-sets-dir option, mysqlcheck: mysqlcheck.         (line  202)
* character-sets-dir option, mysqld:     server-options.     (line  198)
* character-sets-dir option, mysqldump:  mysqldump.          (line  366)
* character-sets-dir option, mysqlimport: mysqlimport.       (line  120)
* character-sets-dir option, mysqlshow:  mysqlshow.          (line  106)
* CHARACTER_LENGTH():                    string-functions.   (line  189)
* character_set_client system variable:  server-system-variables.
                                                             (line  870)
* character_set_connection system variable: server-system-variables.
                                                             (line  908)
* character_set_database system variable: server-system-variables.
                                                             (line  923)
* character_set_filesystem system variable: server-system-variables.
                                                             (line  962)
* character_set_results system variable: server-system-variables.
                                                             (line  993)
* character_set_server system variable:  server-system-variables.
                                                             (line 1008)
* character_set_system system variable:  server-system-variables.
                                                             (line 1027)
* CHARACTER_SETS, INFORMATION_SCHEMA table: character-sets-table.
                                                             (line    6)
* character_sets_dir system variable:    server-system-variables.
                                                             (line 1041)
* characters, multi-byte:                multi-byte-characters.
                                                             (line    6)
* charset command, mysql:                mysql-commands.     (line   61)
* charset option, comp_err:              comp-err.           (line   30)
* CHARSET():                             information-functions.
                                                             (line   79)
* check option, myisamchk:               myisamchk-check-options.
                                                             (line    9)
* check option, mysqlcheck:              mysqlcheck.         (line  207)
* check options, myisamchk:              myisamchk-check-options.
                                                             (line    6)
* CHECK TABLE:                           check-table.        (line    6)
* check-only-changed option, myisamchk:  myisamchk-check-options.
                                                             (line   14)
* check-only-changed option, mysqlcheck: mysqlcheck.         (line  211)
* check-upgrade option, mysqlcheck:      mysqlcheck.         (line  216)
* Checking master version, thread state: slave-io-thread-states.
                                                             (line   20)
* checking permissions, thread state:    general-thread-states.
                                                             (line   23)
* checking privileges on cached query, thread state: query-cache-thread-states.
                                                             (line    9)
* checking query cache for query, thread state: query-cache-thread-states.
                                                             (line   14)
* Checking table, thread state:          general-thread-states.
                                                             (line   28)
* checking, tables for errors:           myisam-check.       (line    6)
* CHECKPOINT Events (MySQL Cluster):     mysql-cluster-log-events.
                                                             (line   35)
* checkpoint option, mysqlhotcopy:       mysqlhotcopy.       (line   94)
* Checksum:                              mysql-cluster-tcp-definition.
                                                             (line  133)
* Checksum (MySQL Cluster) <1>:          mysql-cluster-sci-definition.
                                                             (line  195)
* Checksum (MySQL Cluster):              mysql-cluster-shm-definition.
                                                             (line  130)
* checksum errors:                       solaris.            (line   11)
* CHECKSUM TABLE:                        checksum-table.     (line    6)
* Chinese, Japanese, Korean character sets, frequently asked questions: faqs-cjk.
                                                             (line    6)
* choosing types:                        choosing-types.     (line    6)
* choosing, a MySQL version:             which-version.      (line   19)
* chroot option, mysqld:                 server-options.     (line  279)
* chroot option, mysqlhotcopy:           mysqlhotcopy.       (line   99)
* CJK (Chinese, Japanese, Korean), Access, PHP, etc.: faqs-cjk.
                                                             (line    6)
* CJK (Chinese, Japanese, Korean), availability of specific characters: faqs-cjk.
                                                             (line    6)
* CJK (Chinese, Japanese, Korean), available character sets: faqs-cjk.
                                                             (line    6)
* CJK (Chinese, Japanese, Korean), big5: faqs-cjk.           (line    6)
* CJK (Chinese, Japanese, Korean), character sets available: faqs-cjk.
                                                             (line    6)
* CJK (Chinese, Japanese, Korean), characters displayed as question marks: faqs-cjk.
                                                             (line    6)
* CJK (Chinese, Japanese, Korean), CJKV: faqs-cjk.           (line    6)
* CJK (Chinese, Japanese, Korean), collations: faqs-cjk.     (line    6)
* CJK (Chinese, Japanese, Korean), conversion problems with Japanese character sets: faqs-cjk.
                                                             (line    6)
* CJK (Chinese, Japanese, Korean), data truncation: faqs-cjk.
                                                             (line    6)
* CJK (Chinese, Japanese, Korean), Database and table names: faqs-cjk.
                                                             (line    6)
* CJK (Chinese, Japanese, Korean), documentation in Chinese: faqs-cjk.
                                                             (line    6)
* CJK (Chinese, Japanese, Korean), documentation in Japanese: faqs-cjk.
                                                             (line    6)
* CJK (Chinese, Japanese, Korean), documentation in Korean: faqs-cjk.
                                                             (line    6)
* CJK (Chinese, Japanese, Korean), gb2312, gbk: faqs-cjk.    (line    6)
* CJK (Chinese, Japanese, Korean), Japanese character sets: faqs-cjk.
                                                             (line    6)
* CJK (Chinese, Japanese, Korean), Korean character set: faqs-cjk.
                                                             (line    6)
* CJK (Chinese, Japanese, Korean), LIKE and FULLTEXT: faqs-cjk.
                                                             (line    6)
* CJK (Chinese, Japanese, Korean), MySQL 4.0 behavior: faqs-cjk.
                                                             (line    6)
* CJK (Chinese, Japanese, Korean), ORDER BY treatment: faqs-cjk.
                                                             (line    6)
* CJK (Chinese, Japanese, Korean), problems with Access, PHP, etc.: faqs-cjk.
                                                             (line    6)
* CJK (Chinese, Japanese, Korean), problems with Big5 character sets (Chinese): faqs-cjk.
                                                             (line    6)
* CJK (Chinese, Japanese, Korean), problems with data truncation: faqs-cjk.
                                                             (line    6)
* CJK (Chinese, Japanese, Korean), problems with euckr character set (Korean): faqs-cjk.
                                                             (line    6)
* CJK (Chinese, Japanese, Korean), problems with GB character sets (Chinese): faqs-cjk.
                                                             (line    6)
* CJK (Chinese, Japanese, Korean), problems with LIKE and FULLTEXT: faqs-cjk.
                                                             (line    6)
* CJK (Chinese, Japanese, Korean), problems with Yen sign (Japanese): faqs-cjk.
                                                             (line    6)
* CJK (Chinese, Japanese, Korean), rejected characters: faqs-cjk.
                                                             (line    6)
* CJK (Chinese, Japanese, Korean), sort order problems: faqs-cjk.
                                                             (line    6)
* CJK (Chinese, Japanese, Korean), sorting problems: faqs-cjk.
                                                             (line    6)
* CJK (Chinese, Japanese, Korean), testing availability of characters: faqs-cjk.
                                                             (line    6)
* CJK (Chinese, Japanese, Korean), Unicode collations: faqs-cjk.
                                                             (line    6)
* CJK (Chinese, Japanese, Korean), Vietnamese: faqs-cjk.     (line    6)
* CJK (Chinese, Japanese, Korean), Yen sign: faqs-cjk.       (line    6)
* CJK, FAQ:                              faqs-cjk.           (line    6)
* cleaning up, thread state:             general-thread-states.
                                                             (line   32)
* clear command, mysql:                  mysql-commands.     (line   70)
* clear option, mysql_tableinfo:         mysql-tableinfo.    (line   82)
* clear-only option, mysql_tableinfo:    mysql-tableinfo.    (line   86)
* clearing, caches:                      flush.              (line    6)
* client connection threads:             connection-threads. (line    6)
* client programs:                       programs-overview.  (line  132)
* client programs, building:             building-clients.   (line   11)
* client tools:                          connectors-apis.    (line   23)
* clients, debugging:                    debugging-client.   (line    6)
* clients, threaded:                     threaded-clients.   (line    6)
* CLOSE:                                 close.              (line    6)
* Close stmt, thread command:            thread-commands.    (line   17)
* closing tables, thread state:          general-thread-states.
                                                             (line   37)
* closing, tables:                       table-cache.        (line    6)
* cluster logs <1>:                      mysql-cluster-logging-management-commands.
                                                             (line    6)
* cluster logs:                          mysql-cluster-event-reports.
                                                             (line   12)
* clustered index, InnoDB:               innodb-index-types. (line    6)
* Clustering:                            mysql-cluster.      (line   14)
* CLUSTERLOG commands (MySQL Cluster):   mysql-cluster-logging-management-commands.
                                                             (line    8)
* CLUSTERLOG STATISTICS command (MySQL Cluster): mysql-cluster-log-statistics.
                                                             (line    6)
* CMake:                                 windows-source-build-cmake.
                                                             (line    6)
* COALESCE():                            comparison-operators.
                                                             (line  231)
* COERCIBILITY():                        information-functions.
                                                             (line   90)
* col option, mysql_tableinfo:           mysql-tableinfo.    (line   91)
* ColdFusion:                            connector-odbc-usagenotes-apptips-coldfusion.
                                                             (line    6)
* collating, strings:                    string-collating.   (line    6)
* collation names:                       charset-collation-names.
                                                             (line    6)
* COLLATION():                           information-functions.
                                                             (line  128)
* collation, adding:                     adding-collation.   (line   13)
* collation, modifying:                  adding-collation.   (line   59)
* collation-server option, mysqld:       server-options.     (line  299)
* COLLATION_CHARACTER_SET_APPLICABILITY, INFORMATION_SCHEMA table: collation-character-set-applicability-table.
                                                             (line    6)
* collation_connection system variable:  server-system-variables.
                                                             (line 1060)
* collation_database system variable:    server-system-variables.
                                                             (line 1074)
* collation_server system variable:      server-system-variables.
                                                             (line 1113)
* COLLATIONS, INFORMATION_SCHEMA table:  collations-table.   (line    6)
* collations, naming conventions:        charset-collation-names.
                                                             (line    6)
* column alias, problems:                problems-with-alias.
                                                             (line    6)
* column alias, quoting <1>:             problems-with-alias.
                                                             (line    6)
* column alias, quoting:                 identifiers.        (line   79)
* column comments:                       create-table.       (line  265)
* column names, case sensitivity:        identifier-case-sensitivity.
                                                             (line    6)
* column, changing:                      alter-table.        (line  241)
* column, types:                         data-types.         (line   29)
* column-names option, mysql:            mysql-command-options.
                                                             (line  180)
* COLUMN_PRIVILEGES, INFORMATION_SCHEMA table: column-privileges-table.
                                                             (line    6)
* columns option, mysqlimport:           mysqlimport.        (line  125)
* columns, displaying:                   mysqlshow.          (line    6)
* columns, indexes:                      column-indexes.     (line    6)
* COLUMNS, INFORMATION_SCHEMA table:     columns-table.      (line    6)
* columns, names:                        identifiers.        (line   12)
* columns, other types:                  other-vendor-data-types.
                                                             (line    6)
* columns, selecting:                    selecting-columns.  (line    6)
* columns, storage requirements:         storage-requirements.
                                                             (line    6)
* comma-separated values data, reading <1>: select-into.     (line   91)
* comma-separated values data, reading:  load-data.          (line  314)
* command options (MySQL Cluster), mysqld: mysql-cluster-program-options-mysqld.
                                                             (line    6)
* command options (MySQL Cluster), ndb_mgm: mysql-cluster-programs-ndb-mgm.
                                                             (line   27)
* command options (MySQL Cluster), ndb_mgmd: mysql-cluster-programs-ndb-mgmd.
                                                             (line   12)
* command options (MySQL Cluster), ndbd: mysql-cluster-programs-ndbd.
                                                             (line   17)
* command options, mysql:                mysql-command-options.
                                                             (line    6)
* command options, mysqladmin:           mysqladmin.         (line  209)
* command options, mysqld:               server-options.     (line    6)
* command syntax:                        manual-conventions. (line  120)
* command-line history, mysql:           mysql-history-file. (line    6)
* command-line options (MySQL Cluster):  mysql-cluster-program-options-common.
                                                             (line    6)
* command-line tool:                     mysql.              (line   15)
* commands out of sync:                  commands-out-of-sync.
                                                             (line    6)
* commands, for binary distribution:     binary-installation.
                                                             (line   50)
* comment syntax:                        comments.           (line    6)
* comments option, mysql:                mysql-command-options.
                                                             (line  184)
* comments option, mysqldump:            mysqldump.          (line  371)
* comments, adding:                      comments.           (line    6)
* comments, starting:                    ansi-diff-comments. (line    6)
* COMMIT <1>:                            commit.             (line    6)
* COMMIT:                                ansi-diff-transactions.
                                                             (line    6)
* commit option, mysqlaccess:            mysqlaccess.        (line   75)
* COMMIT, XA transactions:               xa-statements.      (line    6)
* Committing events to binlog, thread state: mysql-cluster-thread-states.
                                                             (line    6)
* comp_err <1>:                          comp-err.           (line    6)
* comp_err:                              programs-overview.  (line   69)
* comp_err, charset option:              comp-err.           (line   30)
* comp_err, debug option:                comp-err.           (line   35)
* comp_err, debug-info option:           comp-err.           (line   40)
* comp_err, header_file option:          comp-err.           (line   44)
* comp_err, help option:                 comp-err.           (line   26)
* comp_err, in_file option:              comp-err.           (line   48)
* comp_err, name_file option:            comp-err.           (line   53)
* comp_err, out_dir option:              comp-err.           (line   57)
* comp_err, out_file option:             comp-err.           (line   62)
* comp_err, statefile option:            comp-err.           (line   66)
* comp_err, version option:              comp-err.           (line   71)
* compact option, mysqldump:             mysqldump.          (line  378)
* comparison operators:                  comparison-operators.
                                                             (line    6)
* compatibility, between MySQL versions: upgrading-from-previous-series.
                                                             (line    6)
* compatibility, with mSQL:              regexp.             (line   32)
* compatibility, with ODBC <1>:          join.               (line  145)
* compatibility, with ODBC <2>:          create-table.       (line  222)
* compatibility, with ODBC <3>:          comparison-operators.
                                                             (line  157)
* compatibility, with ODBC <4>:          type-conversion.    (line   44)
* compatibility, with ODBC <5>:          numeric-type-overview.
                                                             (line  287)
* compatibility, with ODBC <6>:          identifier-qualifiers.
                                                             (line   41)
* compatibility, with ODBC:              server-system-variables.
                                                             (line 4585)
* compatibility, with Oracle <1>:        describe.           (line   40)
* compatibility, with Oracle <2>:        alter-table.        (line  205)
* compatibility, with Oracle <3>:        group-by-functions. (line  245)
* compatibility, with Oracle:            extensions-to-ansi. (line   99)
* compatibility, with PostgreSQL:        extensions-to-ansi. (line  193)
* compatibility, with standard SQL:      compatibility.      (line   15)
* compatibility, with Sybase:            use.                (line   27)
* compatible option, mysqldump:          mysqldump.          (line  393)
* compiler, C++ gcc:                     source-configuration-options.
                                                             (line  350)
* compiling clients, on Unix:            building-clients.   (line   25)
* compiling clients, on Windows:         building-clients.   (line   39)
* compiling, optimizing:                 system-optimization.
                                                             (line    6)
* compiling, problems:                   compilation-problems.
                                                             (line    6)
* compiling, speed:                      compile-and-link-options.
                                                             (line    6)
* compiling, statically:                 source-configuration-options.
                                                             (line  342)
* compiling, user-defined functions:     udf-compiling.      (line    6)
* complete-insert option, mysqldump:     mysqldump.          (line  413)
* completion_type system variable:       server-system-variables.
                                                             (line 1132)
* compound statements:                   sql-syntax-compound-statements.
                                                             (line   16)
* compress option, mysql:                mysql-command-options.
                                                             (line  191)
* compress option, mysqladmin:           mysqladmin.         (line  295)
* compress option, mysqlcheck:           mysqlcheck.         (line  222)
* compress option, mysqldump:            mysqldump.          (line  418)
* compress option, mysqlimport:          mysqlimport.        (line  131)
* compress option, mysqlshow:            mysqlshow.          (line  111)
* COMPRESS():                            encryption-functions.
                                                             (line  131)
* compressed tables <1>:                 compressed-format.  (line    6)
* compressed tables:                     myisampack.         (line    6)
* CONCAT():                              string-functions.   (line  193)
* CONCAT_WS():                           string-functions.   (line  220)
* concatenation, string <1>:             string-functions.   (line  193)
* concatenation, string:                 string-literals.    (line   12)
* concurrent inserts <1>:                concurrent-inserts. (line    6)
* concurrent inserts:                    internal-locking.   (line   73)
* concurrent_insert system variable:     server-system-variables.
                                                             (line 1174)
* conditions <1>:                        show-warnings.      (line    6)
* conditions:                            show-errors.        (line    6)
* Conditions:                            declare-condition.  (line    6)
* config-file option, my_print_defaults: my-print-defaults.  (line   29)
* config-file option, mysqld_multi:      mysqld-multi.       (line  100)
* config-file option, ndb_config:        mysql-cluster-programs-ndb-config.
                                                             (line   66)
* config.cache:                          compilation-problems.
                                                             (line   14)
* config.cache file:                     compilation-problems.
                                                             (line    6)
* config.ini (MySQL Cluster) <1>:        mysql-cluster-programs-ndb-mgmd.
                                                             (line  173)
* config.ini (MySQL Cluster) <2>:        mysql-cluster-config-example.
                                                             (line    6)
* config.ini (MySQL Cluster) <3>:        mysql-cluster-config-file.
                                                             (line   20)
* config.ini (MySQL Cluster):            mysql-cluster-install-configuration.
                                                             (line    6)
* configuration files:                   access-denied.      (line  101)
* configuration options:                 source-configuration-options.
                                                             (line    6)
* configuration, MySQL Cluster:          mysql-cluster-params-overview.
                                                             (line   13)
* configure option, -with-low-memory:    compilation-problems.
                                                             (line   37)
* configure script:                      source-configuration-options.
                                                             (line    6)
* configure, disable-grant-options option: source-configuration-options.
                                                             (line  484)
* configure, enable-profiling option:    source-configuration-options.
                                                             (line  491)
* configure, enable-thread-safe-client option: source-configuration-options.
                                                             (line  459)
* configure, localstatedir option:       source-configuration-options.
                                                             (line  302)
* configure, prefix option:              source-configuration-options.
                                                             (line  302)
* configure, running after prior invocation: compilation-problems.
                                                             (line   14)
* configure, with-big-tables option:     source-configuration-options.
                                                             (line  474)
* configure, with-charset option:        source-configuration-options.
                                                             (line  400)
* configure, with-client-ldflags option: source-configuration-options.
                                                             (line  342)
* configure, with-collation option:      source-configuration-options.
                                                             (line  400)
* configure, with-debug option:          source-configuration-options.
                                                             (line  442)
* configure, with-embedded-server option: source-configuration-options.
                                                             (line  299)
* configure, with-extra-charsets option: source-configuration-options.
                                                             (line  400)
* configure, with-tcp-port option:       source-configuration-options.
                                                             (line  323)
* configure, with-unix-socket-path option: source-configuration-options.
                                                             (line  330)
* configure, with-zlib-dir option:       source-configuration-options.
                                                             (line  465)
* configure, without-server option:      source-configuration-options.
                                                             (line  285)
* configuring backups, in MySQL Cluster: mysql-cluster-backup-configuration.
                                                             (line    6)
* configuring MySQL Cluster <1>:         mysql-cluster-programs-ndb-mgmd.
                                                             (line  173)
* configuring MySQL Cluster <2>:         mysql-cluster-programs-mysqld.
                                                             (line   39)
* configuring MySQL Cluster <3>:         mysql-cluster-configuration.
                                                             (line   14)
* configuring MySQL Cluster:             mysql-cluster-installation.
                                                             (line   15)
* Configuring MySQL Cluster (concepts):  mysql-cluster-basics.
                                                             (line    6)
* connect command, mysql:                mysql-commands.     (line   75)
* Connect Out, thread command:           thread-commands.    (line   25)
* Connect, thread command:               thread-commands.    (line   21)
* connect_timeout system variable:       server-system-variables.
                                                             (line 1214)
* connect_timeout variable <1>:          mysqladmin.         (line  407)
* connect_timeout variable:              mysql-command-options.
                                                             (line  580)
* Connecting to master, thread state:    slave-io-thread-states.
                                                             (line   16)
* connecting, remotely with SSH:         windows-and-ssh.    (line    6)
* connecting, to the server <1>:         connecting.         (line    6)
* connecting, to the server:             connecting-disconnecting.
                                                             (line    6)
* connecting, verification:              connection-access.  (line    6)
* CONNECTION Events (MySQL Cluster):     mysql-cluster-log-events.
                                                             (line   20)
* connection, aborted:                   communication-errors.
                                                             (line    6)
* CONNECTION_ID():                       information-functions.
                                                             (line  137)
* connections option, ndb_config:        mysql-cluster-programs-ndb-config.
                                                             (line  180)
* Connector/C:                           connectors-apis.    (line   23)
* Connector/C++:                         connectors-apis.    (line   23)
* Connector/JDBC:                        connectors-apis.    (line   23)
* Connector/MXJ:                         connectors-apis.    (line   23)
* Connector/Net <1>:                     connector-net.      (line   18)
* Connector/Net:                         connectors-apis.    (line   23)
* Connector/Net, reporting problems:     connector-net-support.
                                                             (line   12)
* Connector/ODBC <1>:                    connector-odbc.     (line   17)
* Connector/ODBC:                        connectors-apis.    (line   23)
* Connector/ODBC, Borland:               connector-odbc-usagenotes-apptips-borland.
                                                             (line   12)
* Connector/ODBC, Borland Database Engine: connector-odbc-usagenotes-apptips-borland.
                                                             (line   12)
* Connector/ODBC, reporting problems:    connector-odbc-support.
                                                             (line   14)
* Connector/OpenOffice.org:              connectors-apis.    (line   23)
* Connectors, MySQL:                     connectors-apis.    (line   23)
* connectstring:                         mysql-cluster-connectstring.
                                                             (line    6)
* console option, mysqld:                server-options.     (line  319)
* const table, optimizer <1>:            select.             (line  381)
* const table, optimizer:                explain-output.     (line  198)
* constant table:                        where-optimizations.
                                                             (line   50)
* constraints:                           constraints.        (line   12)
* CONSTRAINTS, INFORMATION_SCHEMA table: table-constraints-table.
                                                             (line    6)
* Contains():                            functions-that-test-spatial-relationships-between-geometries.
                                                             (line   17)
* contributing companies, list of:       supporters.         (line    6)
* contributors, list of:                 contributors.       (line    6)
* control flow functions:                control-flow-functions.
                                                             (line    6)
* CONV():                                mathematical-functions.
                                                             (line  140)
* conventions, syntax:                   manual-conventions. (line    8)
* conventions, typographical:            manual-conventions. (line    8)
* CONVERT:                               cast-functions.     (line   45)
* CONVERT TO:                            alter-table.        (line  382)
* CONVERT_TZ():                          date-and-time-functions.
                                                             (line  161)
* converting HEAP to MyISAM, thread state: general-thread-states.
                                                             (line   44)
* ConvexHull():                          spatial-operators.  (line   16)
* copy option, mysqlaccess:              mysqlaccess.        (line   82)
* copy to tmp table, thread state:       general-thread-states.
                                                             (line   49)
* copying databases:                     copying-databases.  (line    6)
* copying tables <1>:                    create-table-select.
                                                             (line    6)
* copying tables:                        create-table.       (line  747)
* Copying to group table, thread state:  general-thread-states.
                                                             (line   55)
* Copying to tmp table on disk, thread state: general-thread-states.
                                                             (line   64)
* Copying to tmp table, thread state:    general-thread-states.
                                                             (line   60)
* core-file option, mysqld:              server-options.     (line  331)
* core-file-size option, mysqld_safe:    mysqld-safe.        (line  149)
* correct-checksum option, myisamchk:    myisamchk-repair-options.
                                                             (line   19)
* correlated subqueries:                 correlated-subqueries.
                                                             (line    6)
* COS():                                 mathematical-functions.
                                                             (line  160)
* COT():                                 mathematical-functions.
                                                             (line  167)
* count option, myisam_ftdump:           myisam-ftdump.      (line   62)
* count option, mysqladmin:              mysqladmin.         (line  300)
* count option, mysqlshow:               mysqlshow.          (line  116)
* COUNT():                               group-by-functions. (line   95)
* COUNT(DISTINCT):                       group-by-functions. (line  125)
* counting, table rows:                  counting-rows.      (line    6)
* CR_SERVER_GONE_ERROR:                  gone-away.          (line    6)
* CR_SERVER_LOST_ERROR:                  gone-away.          (line    6)
* crash:                                 debugging-server.   (line   16)
* crash, recovery:                       myisam-crash-recovery.
                                                             (line    6)
* crash, repeated:                       crashing.           (line    6)
* crash, replication:                    replication-features-shutdowns.
                                                             (line    6)
* crash-me:                              mysql-benchmarks.   (line   43)
* crash-me program <1>:                  mysql-benchmarks.   (line    6)
* crash-me program:                      portability.        (line    6)
* CRC32():                               mathematical-functions.
                                                             (line  176)
* CREATE DATABASE:                       create-database.    (line    6)
* Create DB, thread command:             thread-commands.    (line   29)
* CREATE FUNCTION <1>:                   create-function-udf.
                                                             (line    6)
* CREATE FUNCTION:                       create-procedure.   (line    6)
* CREATE INDEX:                          create-index.       (line    6)
* CREATE PROCEDURE:                      create-procedure.   (line    6)
* CREATE SCHEMA:                         create-database.    (line    6)
* CREATE TABLE:                          create-table.       (line   11)
* CREATE TABLE ... SELECT, and replication: replication-features-create-select.
                                                             (line    6)
* CREATE TABLE, DIRECTORY options, and replication: replication-features-directory.
                                                             (line    6)
* CREATE TRIGGER:                        create-trigger.     (line    6)
* CREATE USER:                           create-user.        (line    6)
* CREATE VIEW:                           create-view.        (line    6)
* create-options option, mysqldump:      mysqldump.          (line  423)
* Creating delayed handler, thread state: delayed-insert-thread-states.
                                                             (line   22)
* Creating index, thread state:          general-thread-states.
                                                             (line   72)
* Creating sort index, thread state:     general-thread-states.
                                                             (line   77)
* Creating table from master dump, thread state: slave-connection-thread-states.
                                                             (line   14)
* creating table, thread state:          general-thread-states.
                                                             (line   82)
* Creating tmp table, thread state:      general-thread-states.
                                                             (line   87)
* creating user accounts:                create-user.        (line    6)
* creating, bug reports:                 bug-reports.        (line    6)
* creating, database:                    create-database.    (line    6)
* creating, databases:                   database-use.       (line   13)
* creating, default startup options:     option-files.       (line   11)
* creating, function:                    create-function-udf.
                                                             (line    6)
* creating, schema:                      create-database.    (line    6)
* creating, tables:                      creating-tables.    (line    6)
* CROSS JOIN:                            join.               (line    6)
* Crosses():                             functions-that-test-spatial-relationships-between-geometries.
                                                             (line   22)
* CSV data, reading <1>:                 select-into.        (line   91)
* CSV data, reading:                     load-data.          (line  314)
* CSV storage engine <1>:                csv-storage-engine. (line    6)
* CSV storage engine:                    storage-engines.    (line   19)
* CURDATE():                             date-and-time-functions.
                                                             (line  189)
* CURRENT_DATE:                          date-and-time-functions.
                                                             (line  200)
* CURRENT_TIME:                          date-and-time-functions.
                                                             (line  216)
* CURRENT_TIMESTAMP:                     date-and-time-functions.
                                                             (line  220)
* CURRENT_USER():                        information-functions.
                                                             (line  146)
* Cursors:                               cursors.            (line   13)
* CURTIME():                             date-and-time-functions.
                                                             (line  204)
* CXX environment variable <1>:          environment-variables.
                                                             (line   18)
* CXX environment variable <2>:          compilation-problems.
                                                             (line   65)
* CXX environment variable:              source-configuration-options.
                                                             (line  350)
* CXXFLAGS environment variable <1>:     environment-variables.
                                                             (line   18)
* CXXFLAGS environment variable <2>:     compilation-problems.
                                                             (line   88)
* CXXFLAGS environment variable:         source-configuration-options.
                                                             (line  364)
* Daemon, thread command:                thread-commands.    (line   33)
* DATA DIRECTORY, and replication:       replication-features-directory.
                                                             (line    6)
* data node (MySQL Cluster), defined:    mysql-cluster-basics.
                                                             (line    6)
* data nodes (MySQL Cluster):            mysql-cluster-programs-ndbd.
                                                             (line    6)
* Data truncation with CJK characters:   faqs-cjk.           (line    6)
* data type, BIGINT:                     numeric-type-overview.
                                                             (line  130)
* data type, BINARY <1>:                 binary-varbinary.   (line    6)
* data type, BINARY:                     string-type-overview.
                                                             (line  187)
* data type, BIT:                        numeric-type-overview.
                                                             (line   35)
* data type, BLOB <1>:                   blob.               (line    6)
* data type, BLOB:                       string-type-overview.
                                                             (line  217)
* data type, BOOL <1>:                   other-vendor-data-types.
                                                             (line    6)
* data type, BOOL:                       numeric-type-overview.
                                                             (line   50)
* data type, BOOLEAN <1>:                other-vendor-data-types.
                                                             (line    6)
* data type, BOOLEAN:                    numeric-type-overview.
                                                             (line   50)
* data type, CHAR <1>:                   string-types.       (line   14)
* data type, CHAR:                       string-type-overview.
                                                             (line  100)
* data type, CHAR VARYING:               string-type-overview.
                                                             (line  147)
* data type, CHARACTER:                  string-type-overview.
                                                             (line  100)
* data type, CHARACTER VARYING:          string-type-overview.
                                                             (line  147)
* data type, DATE <1>:                   datetime.           (line   10)
* data type, DATE:                       date-and-time-type-overview.
                                                             (line   16)
* data type, DATETIME <1>:               datetime.           (line   10)
* data type, DATETIME:                   date-and-time-type-overview.
                                                             (line   23)
* data type, DEC:                        numeric-type-overview.
                                                             (line  220)
* data type, DECIMAL <1>:                precision-math.     (line   14)
* data type, DECIMAL:                    numeric-type-overview.
                                                             (line  175)
* data type, DOUBLE:                     numeric-type-overview.
                                                             (line  248)
* data type, DOUBLE PRECISION:           numeric-type-overview.
                                                             (line  265)
* data type, ENUM <1>:                   enum.               (line    6)
* data type, ENUM:                       string-type-overview.
                                                             (line  279)
* data type, FIXED:                      numeric-type-overview.
                                                             (line  220)
* data type, FLOAT:                      numeric-type-overview.
                                                             (line  228)
* data type, GEOMETRY:                   mysql-spatial-datatypes.
                                                             (line    6)
* data type, GEOMETRYCOLLECTION:         mysql-spatial-datatypes.
                                                             (line    6)
* data type, INT:                        numeric-type-overview.
                                                             (line  121)
* data type, INTEGER:                    numeric-type-overview.
                                                             (line  126)
* data type, LINESTRING:                 mysql-spatial-datatypes.
                                                             (line    6)
* data type, LONG:                       blob.               (line    6)
* data type, LONGBLOB:                   string-type-overview.
                                                             (line  257)
* data type, LONGTEXT:                   string-type-overview.
                                                             (line  267)
* data type, MEDIUMBLOB:                 string-type-overview.
                                                             (line  241)
* data type, MEDIUMINT:                  numeric-type-overview.
                                                             (line  116)
* data type, MEDIUMTEXT:                 string-type-overview.
                                                             (line  248)
* data type, MULTILINESTRING:            mysql-spatial-datatypes.
                                                             (line    6)
* data type, MULTIPOINT:                 mysql-spatial-datatypes.
                                                             (line    6)
* data type, MULTIPOLYGON:               mysql-spatial-datatypes.
                                                             (line    6)
* data type, NATIONAL CHAR:              string-type-overview.
                                                             (line  100)
* data type, NATIONAL VARCHAR:           string-type-overview.
                                                             (line  147)
* data type, NCHAR:                      string-type-overview.
                                                             (line  100)
* data type, NUMERIC:                    numeric-type-overview.
                                                             (line  220)
* data type, NVARCHAR:                   string-type-overview.
                                                             (line  147)
* data type, POINT:                      mysql-spatial-datatypes.
                                                             (line    6)
* data type, POLYGON:                    mysql-spatial-datatypes.
                                                             (line    6)
* data type, REAL:                       numeric-type-overview.
                                                             (line  265)
* data type, SET <1>:                    set.                (line    6)
* data type, SET:                        string-type-overview.
                                                             (line  288)
* data type, SMALLINT:                   numeric-type-overview.
                                                             (line  111)
* data type, TEXT <1>:                   blob.               (line    6)
* data type, TEXT:                       string-type-overview.
                                                             (line  228)
* data type, TIME <1>:                   time.               (line    6)
* data type, TIME:                       date-and-time-type-overview.
                                                             (line   63)
* data type, TIMESTAMP <1>:              datetime.           (line   10)
* data type, TIMESTAMP:                  date-and-time-type-overview.
                                                             (line   31)
* data type, TINYBLOB:                   string-type-overview.
                                                             (line  201)
* data type, TINYINT:                    numeric-type-overview.
                                                             (line   45)
* data type, TINYTEXT:                   string-type-overview.
                                                             (line  208)
* data type, VARBINARY <1>:              binary-varbinary.   (line    6)
* data type, VARBINARY:                  string-type-overview.
                                                             (line  194)
* data type, VARCHAR <1>:                string-types.       (line   14)
* data type, VARCHAR:                    string-type-overview.
                                                             (line  147)
* data type, VARCHARACTER:               string-type-overview.
                                                             (line  147)
* data type, YEAR <1>:                   year.               (line    6)
* data type, YEAR:                       date-and-time-type-overview.
                                                             (line   70)
* data types:                            data-types.         (line   29)
* data types, C API:                     c.                  (line   25)
* data types, overview:                  data-type-overview. (line   13)
* data, importing <1>:                   mysqlimport.        (line    6)
* data, importing:                       batch-commands.     (line    6)
* data, loading into tables:             loading-tables.     (line    6)
* data, retrieving:                      retrieving-data.    (line   18)
* data, size:                            data-size.          (line    6)
* data-file-length option, myisamchk:    myisamchk-repair-options.
                                                             (line   23)
* Database information, obtaining:       show.               (line   46)
* database metadata:                     information-schema. (line   28)
* database names, case sensitivity:      identifier-case-sensitivity.
                                                             (line    6)
* database names, case-sensitivity:      extensions-to-ansi. (line   38)
* database option, mysql:                mysql-command-options.
                                                             (line  196)
* database option, mysqlbinlog:          mysqlbinlog.        (line  151)
* database option, ndb_show_tables:      mysql-cluster-programs-ndb-show-tables.
                                                             (line   36)
* DATABASE():                            information-functions.
                                                             (line  180)
* database, altering:                    alter-database.     (line    6)
* database, creating:                    create-database.    (line    6)
* database, deleting:                    drop-database.      (line    6)
* databases option, mysqlcheck:          mysqlcheck.         (line  227)
* databases option, mysqldump:           mysqldump.          (line  428)
* databases, backups:                    backup-and-recovery.
                                                             (line   15)
* databases, copying:                    copying-databases.  (line    6)
* databases, creating:                   database-use.       (line   13)
* databases, defined:                    what-is-mysql.      (line   25)
* databases, displaying:                 mysqlshow.          (line    6)
* databases, dumping <1>:                mysqlhotcopy.       (line    6)
* databases, dumping:                    mysqldump.          (line    6)
* databases, information about:          getting-information.
                                                             (line    6)
* databases, names:                      identifiers.        (line   12)
* databases, replicating:                replication.        (line   13)
* databases, selecting:                  creating-database.  (line    6)
* databases, symbolic links:             symbolic-links-to-databases.
                                                             (line    6)
* databases, using:                      database-use.       (line   13)
* DataDir <1>:                           mysql-cluster-ndbd-definition.
                                                             (line  218)
* DataDir:                               mysql-cluster-mgm-definition.
                                                             (line  208)
* datadir option, mysql.server:          mysql-server.       (line   40)
* datadir option, mysql_install_db:      mysql-install-db.   (line   55)
* datadir option, mysql_upgrade:         mysql-upgrade.      (line  108)
* datadir option, mysqld:                server-options.     (line  360)
* datadir option, mysqld_safe:           mysqld-safe.        (line  154)
* datadir system variable:               server-system-variables.
                                                             (line 1248)
* DataJunction:                          connector-odbc-usagenotes-apptips-datajunction.
                                                             (line    6)
* DataMemory <1>:                        mysql-cluster-config-lcp-params.
                                                             (line    6)
* DataMemory:                            mysql-cluster-ndbd-definition.
                                                             (line  294)
* DATE:                                  using-date.         (line    6)
* date and time functions:               date-and-time-functions.
                                                             (line    6)
* Date and Time types:                   date-and-time-types.
                                                             (line   15)
* date calculations:                     date-calculations.  (line    6)
* DATE columns, problems:                using-date.         (line    6)
* DATE data type <1>:                    datetime.           (line   10)
* DATE data type:                        date-and-time-type-overview.
                                                             (line   16)
* date literals:                         date-and-time-literals.
                                                             (line    6)
* date option, mysql_explain_log:        mysql-explain-log.  (line   29)
* date types:                            storage-requirements.
                                                             (line  132)
* date values, problems:                 datetime.           (line   47)
* DATE():                                date-and-time-functions.
                                                             (line  225)
* DATE_ADD():                            date-and-time-functions.
                                                             (line  244)
* date_format system variable:           server-system-variables.
                                                             (line 1269)
* DATE_FORMAT():                         date-and-time-functions.
                                                             (line  404)
* DATE_SUB():                            date-and-time-functions.
                                                             (line  244)
* DATEDIFF():                            date-and-time-functions.
                                                             (line  232)
* DATETIME data type <1>:                datetime.           (line   10)
* DATETIME data type:                    date-and-time-type-overview.
                                                             (line   23)
* datetime_format system variable:       server-system-variables.
                                                             (line 1273)
* DAY():                                 date-and-time-functions.
                                                             (line  489)
* DAYNAME():                             date-and-time-functions.
                                                             (line  493)
* DAYOFMONTH():                          date-and-time-functions.
                                                             (line  502)
* DAYOFWEEK():                           date-and-time-functions.
                                                             (line  511)
* DAYOFYEAR():                           date-and-time-functions.
                                                             (line  520)
* db option, mysqlaccess:                mysqlaccess.        (line   86)
* db table, sorting:                     request-access.     (line   51)
* DB2 SQL mode:                          server-sql-mode.    (line  406)
* DBI interface:                         apis-perl.          (line    6)
* DBI->quote:                            string-literals.    (line  141)
* DBI->trace:                            using-gdb-on-mysqld.
                                                             (line   89)
* DBI/DBD interface:                     apis-perl.          (line    6)
* DBI_TRACE environment variable <1>:    using-gdb-on-mysqld.
                                                             (line   89)
* DBI_TRACE environment variable:        environment-variables.
                                                             (line   18)
* DBI_USER environment variable:         environment-variables.
                                                             (line   18)
* DBUG package:                          the-dbug-package.   (line    6)
* DEALLOCATE PREPARE <1>:                deallocate-prepare. (line    6)
* DEALLOCATE PREPARE:                    sql-syntax-prepared-statements.
                                                             (line   12)
* debug option, comp_err:                comp-err.           (line   35)
* debug option, make_win_bin_dist:       make-win-bin-dist.  (line   36)
* debug option, make_win_src_distribution: make-win-src-distribution.
                                                             (line   24)
* debug option, my_print_defaults:       my-print-defaults.  (line   35)
* debug option, myisamchk:               myisamchk-general-options.
                                                             (line   21)
* debug option, myisampack:              myisampack.         (line   61)
* debug option, mysql:                   mysql-command-options.
                                                             (line  200)
* debug option, mysqlaccess:             mysqlaccess.        (line   90)
* debug option, mysqladmin:              mysqladmin.         (line  305)
* debug option, mysqlbinlog:             mysqlbinlog.        (line  205)
* debug option, mysqlcheck:              mysqlcheck.         (line  235)
* debug option, mysqld:                  server-options.     (line  380)
* debug option, mysqldump:               mysqldump.          (line  437)
* debug option, mysqldumpslow:           mysqldumpslow.      (line   53)
* debug option, mysqlhotcopy:            mysqlhotcopy.       (line  105)
* debug option, mysqlimport:             mysqlimport.        (line  136)
* debug option, mysqlshow:               mysqlshow.          (line  121)
* Debug, thread command:                 thread-commands.    (line   38)
* debug-info option, comp_err:           comp-err.           (line   40)
* debug-info option, mysql:              mysql-command-options.
                                                             (line  205)
* debug-info option, mysqldump:          mysqldump.          (line  443)
* debugging support:                     source-configuration-options.
                                                             (line    6)
* debugging, client:                     debugging-client.   (line    6)
* debugging, server:                     debugging-server.   (line   16)
* DEC data type:                         numeric-type-overview.
                                                             (line  220)
* decimal arithmetic:                    precision-math.     (line   14)
* DECIMAL data type <1>:                 precision-math.     (line   14)
* DECIMAL data type:                     numeric-type-overview.
                                                             (line  175)
* decimal point:                         data-types.         (line   37)
* DECLARE:                               declare.            (line    6)
* DECODE():                              encryption-functions.
                                                             (line  164)
* decode_bits myisamchk variable:        myisamchk-general-options.
                                                             (line   53)
* default host name:                     connecting.         (line    6)
* default installation location:         installation-layouts.
                                                             (line    6)
* default options:                       option-files.       (line   11)
* DEFAULT value clause <1>:              create-table.       (line  244)
* DEFAULT value clause:                  data-type-defaults. (line    6)
* default values <1>:                    insert.             (line   70)
* default values <2>:                    create-table.       (line  244)
* default values <3>:                    data-type-defaults. (line    6)
* default values:                        design-limitations. (line   20)
* default values, BLOB and TEXT columns: blob.               (line   63)
* default values, explicit:              data-type-defaults. (line    6)
* default values, implicit:              data-type-defaults. (line    6)
* default values, suppression:           constraint-invalid-data.
                                                             (line    6)
* DEFAULT():                             miscellaneous-functions.
                                                             (line   27)
* DEFAULT, constraint:                   constraint-invalid-data.
                                                             (line    6)
* default, privileges:                   default-privileges. (line    6)
* default-character-set option, mysql:   mysql-command-options.
                                                             (line  209)
* default-character-set option, mysqladmin: mysqladmin.      (line  311)
* default-character-set option, mysqlcheck: mysqlcheck.      (line  240)
* default-character-set option, mysqld:  server-options.     (line  409)
* default-character-set option, mysqldump: mysqldump.        (line  448)
* default-character-set option, mysqlimport: mysqlimport.    (line  141)
* default-character-set option, mysqlshow: mysqlshow.        (line  126)
* default-collation option, mysqld:      server-options.     (line  429)
* default-mysqld-path option, mysqlmanager: instance-manager-command-options.
                                                             (line   46)
* default-storage-engine option, mysqld: server-options.     (line  446)
* default-table-type option, mysqld:     server-options.     (line  460)
* default-time-zone option, mysqld:      server-options.     (line  477)
* default_week_format system variable:   server-system-variables.
                                                             (line 1277)
* defaults-extra-file option:            option-file-options.
                                                             (line   22)
* defaults-extra-file option, my_print_defaults: my-print-defaults.
                                                             (line   41)
* defaults-extra-file option, mysqld_multi: mysqld-multi.    (line   68)
* defaults-extra-file option, mysqld_safe: mysqld-safe.      (line  158)
* defaults-file option:                  option-file-options.
                                                             (line   29)
* defaults-file option, my_print_defaults: my-print-defaults.
                                                             (line   31)
* defaults-file option, mysqld_multi:    mysqld-multi.       (line   66)
* defaults-file option, mysqld_safe:     mysqld-safe.        (line  165)
* defaults-file option, mysqlmanager:    instance-manager-command-options.
                                                             (line   55)
* defaults-group-suffix option:          option-file-options.
                                                             (line   35)
* defaults-group-suffix option, my_print_defaults: my-print-defaults.
                                                             (line   48)
* DEGREES():                             mathematical-functions.
                                                             (line  188)
* delay-key-write option, mysqld <1>:    myisam-start.       (line   42)
* delay-key-write option, mysqld:        server-options.     (line  493)
* delay_key_write system variable:       server-system-variables.
                                                             (line 1300)
* DELAYED:                               insert-delayed.     (line    6)
* Delayed insert, thread command:        thread-commands.    (line   42)
* delayed inserts, thread states:        delayed-insert-thread-states.
                                                             (line    6)
* DELAYED, when ignored:                 insert.             (line  226)
* delayed-insert option, mysqldump:      mysqldump.          (line  458)
* delayed_insert_limit:                  insert-delayed.     (line  118)
* delayed_insert_limit system variable:  server-system-variables.
                                                             (line 1347)
* delayed_insert_timeout system variable: server-system-variables.
                                                             (line 1381)
* delayed_queue_size system variable:    server-system-variables.
                                                             (line 1402)
* DELETE:                                delete.             (line    6)
* delete option, mysqlimport:            mysqlimport.        (line  146)
* DELETE, and MySQL Cluster:             mysql-cluster-limitations-limits.
                                                             (line    9)
* delete-master-logs option, mysqldump:  mysqldump.          (line  463)
* deleting from main table, thread state: general-thread-states.
                                                             (line   94)
* deleting from reference tables, thread state: general-thread-states.
                                                             (line  100)
* deleting, database:                    drop-database.      (line    6)
* deleting, foreign key <1>:             innodb-foreign-key-constraints.
                                                             (line  162)
* deleting, foreign key:                 alter-table.        (line  351)
* deleting, function:                    drop-function-udf.  (line    6)
* deleting, index <1>:                   drop-index.         (line    6)
* deleting, index:                       alter-table.        (line  248)
* deleting, primary key:                 alter-table.        (line  263)
* deleting, rows:                        deleting-from-related-tables.
                                                             (line    6)
* deleting, schema:                      drop-database.      (line    6)
* deleting, table:                       drop-table.         (line    6)
* deleting, user <1>:                    drop-user.          (line    6)
* deleting, user:                        removing-users.     (line    6)
* deleting, users <1>:                   drop-user.          (line    6)
* deleting, users:                       removing-users.     (line    6)
* deletion, mysql.sock:                  problems-with-mysql-sock.
                                                             (line    6)
* delimiter command, mysql:              mysql-commands.     (line   82)
* delimiter option, mysql:               mysql-command-options.
                                                             (line  223)
* delimiter option, ndb_select_all:      mysql-cluster-programs-ndb-select-all.
                                                             (line   49)
* Delphi:                                connector-odbc-usagenotes-apptips-borland-delphi.
                                                             (line    6)
* derived tables:                        from-clause-subqueries.
                                                             (line    6)
* des-key-file option, mysqld:           server-options.     (line  527)
* DES_DECRYPT():                         encryption-functions.
                                                             (line  169)
* DES_ENCRYPT():                         encryption-functions.
                                                             (line  190)
* DESC:                                  describe.           (line    6)
* descending option, ndb_select_all:     mysql-cluster-programs-ndb-select-all.
                                                             (line   34)
* DESCRIBE <1>:                          describe.           (line    6)
* DESCRIBE:                              getting-information.
                                                             (line    6)
* description option, myisamchk:         myisamchk-other-options.
                                                             (line   22)
* design, issues:                        bugs.               (line    6)
* design, limitations:                   design-limitations. (line    6)
* development of MySQL Cluster:          mysql-cluster-development.
                                                             (line   10)
* development source tree:               installing-development-tree.
                                                             (line    6)
* Difference():                          spatial-operators.  (line   21)
* digits:                                data-types.         (line   37)
* Dimension():                           general-geometry-property-functions.
                                                             (line    9)
* directory structure, default:          installation-layouts.
                                                             (line    6)
* dirname option, make_win_src_distribution: make-win-src-distribution.
                                                             (line   28)
* disable named command, mysql:          mysql-command-options.
                                                             (line  228)
* disable-grant-options option, configure: source-configuration-options.
                                                             (line  484)
* disable-keys option, mysqldump:        mysqldump.          (line  470)
* disable-log-bin option, mysqlbinlog:   mysqlbinlog.        (line  211)
* DISCARD TABLESPACE <1>:                innodb-multiple-tablespaces.
                                                             (line   59)
* DISCARD TABLESPACE:                    alter-table.        (line  362)
* discard_or_import_tablespace, thread state: general-thread-states.
                                                             (line  105)
* disconnect-slave-event-count option, mysqld: replication-options-slave.
                                                             (line  149)
* disconnecting, from the server:        connecting-disconnecting.
                                                             (line    6)
* Disjoint():                            functions-that-test-spatial-relationships-between-geometries.
                                                             (line   40)
* disk full:                             full-disk.          (line    6)
* disk performance:                      disk-issues.        (line    6)
* Diskless:                              mysql-cluster-ndbd-definition.
                                                             (line 1210)
* disks, splitting data across:          windows-symbolic-links.
                                                             (line    6)
* display size:                          data-types.         (line   31)
* display triggers:                      show-triggers.      (line    6)
* display width:                         data-types.         (line   31)
* displaying, database information:      mysqlshow.          (line    6)
* displaying, information, Cardinality:  show-index.         (line   42)
* displaying, information, Collation:    show-index.         (line   37)
* displaying, information, SHOW <1>:     show-tables.        (line    6)
* displaying, information, SHOW <2>:     show-open-tables.   (line    6)
* displaying, information, SHOW <3>:     show-index.         (line    6)
* displaying, information, SHOW <4>:     show-columns.       (line    6)
* displaying, information, SHOW:         show.               (line   46)
* displaying, table status:              show-table-status.  (line    6)
* DISTINCT <1>:                          select.             (line  357)
* DISTINCT <2>:                          distinct-optimization.
                                                             (line    6)
* DISTINCT:                              selecting-columns.  (line   43)
* DISTINCT, AVG():                       group-by-functions. (line   60)
* DISTINCT, COUNT():                     group-by-functions. (line  125)
* DISTINCT, MAX():                       group-by-functions. (line  197)
* DISTINCT, MIN():                       group-by-functions. (line  217)
* DISTINCT, SUM():                       group-by-functions. (line  269)
* DISTINCTROW:                           select.             (line  357)
* DIV:                                   arithmetic-functions.
                                                             (line  108)
* div_precision_increment system variable: server-system-variables.
                                                             (line 1436)
* division (/):                          arithmetic-functions.
                                                             (line   92)
* DNS:                                   dns.                (line    6)
* DO:                                    do.                 (line    6)
* DocBook XML, documentation source format: manual-info.     (line   32)
* Documentation, in Chinese:             faqs-cjk.           (line    6)
* Documentation, in Japanese:            faqs-cjk.           (line    6)
* Documentation, in Korean:              faqs-cjk.           (line    6)
* Documenters, list of:                  documenters-translators.
                                                             (line    6)
* DOUBLE data type:                      numeric-type-overview.
                                                             (line  248)
* DOUBLE PRECISION data type:            numeric-type-overview.
                                                             (line  265)
* double quote (\"):                     string-literals.    (line   70)
* downgrades, MySQL Cluster <1>:         mysql-cluster-rolling-restart.
                                                             (line    6)
* downgrades, MySQL Cluster:             mysql-cluster-upgrade-downgrade.
                                                             (line    6)
* downgrading <1>:                       downgrading.        (line   10)
* downgrading:                           upgrading-downgrading.
                                                             (line   14)
* downloading:                           getting-mysql.      (line    6)
* DRBD license:                          faqs-drbd.          (line    6)
* drbd, FAQ <1>:                         faqs-drbd.          (line    6)
* drbd, FAQ:                             faqs-mysql-drbd-heartbeat.
                                                             (line   19)
* DROP ... IF EXISTS, and replication:   replication-features-drop-if-exists.
                                                             (line    6)
* DROP DATABASE:                         drop-database.      (line    6)
* Drop DB, thread command:               thread-commands.    (line   46)
* DROP FOREIGN KEY <1>:                  innodb-foreign-key-constraints.
                                                             (line  162)
* DROP FOREIGN KEY:                      alter-table.        (line  351)
* DROP FUNCTION <1>:                     drop-function-udf.  (line    6)
* DROP FUNCTION:                         drop-procedure.     (line    6)
* DROP INDEX <1>:                        drop-index.         (line    6)
* DROP INDEX:                            alter-table.        (line  248)
* DROP PREPARE:                          deallocate-prepare. (line    6)
* DROP PRIMARY KEY:                      alter-table.        (line  263)
* DROP PROCEDURE:                        drop-procedure.     (line    6)
* DROP SCHEMA:                           drop-database.      (line    6)
* DROP TABLE:                            drop-table.         (line    6)
* DROP TABLE, and MySQL Cluster:         mysql-cluster-limitations-limits.
                                                             (line    9)
* DROP TRIGGER:                          drop-trigger.       (line    6)
* DROP USER:                             drop-user.          (line    6)
* DROP VIEW:                             drop-view.          (line    6)
* dropping, user <1>:                    drop-user.          (line    6)
* dropping, user:                        removing-users.     (line    6)
* dryrun option, mysqlhotcopy:           mysqlhotcopy.       (line  109)
* DUAL:                                  select.             (line   65)
* dump option, myisam_ftdump:            myisam-ftdump.      (line   66)
* dump-date option, mysqldump:           mysqldump.          (line  479)
* DUMPFILE:                              select-into.        (line   99)
* dumping, databases and tables <1>:     mysqlhotcopy.       (line    6)
* dumping, databases and tables:         mysqldump.          (line    6)
* dynamic table characteristics:         dynamic-format.     (line    6)
* edit command, mysql:                   mysql-commands.     (line  117)
* ego command, mysql:                    mysql-commands.     (line  126)
* Eiffel Wrapper:                        apis-eiffel.        (line    6)
* ELT():                                 string-functions.   (line  237)
* email lists:                           mailing-lists.      (line   10)
* embedded MySQL server library:         libmysqld.          (line    6)
* embedded option, make_win_bin_dist:    make-win-bin-dist.  (line   41)
* embedded option, mysql_config:         mysql-config.       (line   24)
* enable-named-pipe option, mysqld:      server-options.     (line  537)
* enable-profiling option, configure:    source-configuration-options.
                                                             (line  491)
* enable-pstack option, mysqld:          server-options.     (line  551)
* enable-thread-safe-client option, configure: source-configuration-options.
                                                             (line  459)
* ENCODE():                              encryption-functions.
                                                             (line  241)
* ENCRYPT():                             encryption-functions.
                                                             (line  251)
* encryption:                            secure-basics.      (line   18)
* encryption functions:                  encryption-functions.
                                                             (line    6)
* END:                                   begin-end.          (line    6)
* end, thread state:                     general-thread-states.
                                                             (line  110)
* EndPoint():                            linestring-property-functions.
                                                             (line   10)
* engine_condition_pushdown system variable: server-system-variables.
                                                             (line 1479)
* enhancements, MySQL Community Server <1>: news-5-0-x.      (line  115)
* enhancements, MySQL Community Server:  news.               (line   17)
* enhancements, MySQL Enterprise <1>:    news-5-0-x.         (line  115)
* enhancements, MySQL Enterprise:        news.               (line   17)
* ENTER SINGLE USER MODE command (MySQL Cluster): mysql-cluster-mgm-client-commands.
                                                             (line   91)
* entering, queries:                     entering-queries.   (line    6)
* ENUM data type <1>:                    enum.               (line    6)
* ENUM data type:                        string-type-overview.
                                                             (line  279)
* ENUM, size:                            storage-requirements.
                                                             (line  253)
* Envelope():                            general-geometry-property-functions.
                                                             (line   22)
* environment variable, CC <1>:          environment-variables.
                                                             (line   18)
* environment variable, CC <2>:          compilation-problems.
                                                             (line   88)
* environment variable, CC:              source-configuration-options.
                                                             (line  350)
* environment variable, CFLAGS <1>:      environment-variables.
                                                             (line   18)
* environment variable, CFLAGS <2>:      compilation-problems.
                                                             (line   88)
* environment variable, CFLAGS:          source-configuration-options.
                                                             (line  364)
* environment variable, CXX <1>:         environment-variables.
                                                             (line   18)
* environment variable, CXX <2>:         compilation-problems.
                                                             (line   65)
* environment variable, CXX:             source-configuration-options.
                                                             (line  350)
* environment variable, CXXFLAGS <1>:    environment-variables.
                                                             (line   18)
* environment variable, CXXFLAGS <2>:    compilation-problems.
                                                             (line   88)
* environment variable, CXXFLAGS:        source-configuration-options.
                                                             (line  364)
* environment variable, DBI_TRACE <1>:   using-gdb-on-mysqld.
                                                             (line   89)
* environment variable, DBI_TRACE:       environment-variables.
                                                             (line   18)
* environment variable, DBI_USER:        environment-variables.
                                                             (line   18)
* environment variable, HOME <1>:        mysql-history-file. (line    6)
* environment variable, HOME:            environment-variables.
                                                             (line   18)
* environment variable, LD_LIBRARY_PATH: perl-support-problems.
                                                             (line   23)
* environment variable, LD_RUN_PATH <1>: perl-support-problems.
                                                             (line   23)
* environment variable, LD_RUN_PATH <2>: environment-variables.
                                                             (line   18)
* environment variable, LD_RUN_PATH <3>: solaris.            (line  145)
* environment variable, LD_RUN_PATH:     source-notes-linux. (line   98)
* environment variable, MYSQL_DEBUG <1>: debugging-client.   (line   10)
* environment variable, MYSQL_DEBUG <2>: programs-overview.  (line  329)
* environment variable, MYSQL_DEBUG:     environment-variables.
                                                             (line   18)
* environment variable, MYSQL_GROUP_SUFFIX: environment-variables.
                                                             (line   18)
* environment variable, MYSQL_HISTFILE <1>: mysql-history-file.
                                                             (line    6)
* environment variable, MYSQL_HISTFILE:  environment-variables.
                                                             (line   18)
* environment variable, MYSQL_HOME:      environment-variables.
                                                             (line   18)
* environment variable, MYSQL_HOST <1>:  connecting.         (line  231)
* environment variable, MYSQL_HOST:      environment-variables.
                                                             (line   18)
* environment variable, MYSQL_PS1:       environment-variables.
                                                             (line   18)
* environment variable, MYSQL_PWD <1>:   connecting.         (line  231)
* environment variable, MYSQL_PWD <2>:   programs-overview.  (line  329)
* environment variable, MYSQL_PWD:       environment-variables.
                                                             (line   18)
* environment variable, MYSQL_TCP_PORT <1>: multiple-server-clients.
                                                             (line   27)
* environment variable, MYSQL_TCP_PORT <2>: multiple-unix-servers.
                                                             (line   68)
* environment variable, MYSQL_TCP_PORT <3>: programs-overview.
                                                             (line  329)
* environment variable, MYSQL_TCP_PORT:  environment-variables.
                                                             (line   18)
* environment variable, MYSQL_UNIX_PORT <1>: multiple-server-clients.
                                                             (line   27)
* environment variable, MYSQL_UNIX_PORT <2>: multiple-unix-servers.
                                                             (line   68)
* environment variable, MYSQL_UNIX_PORT <3>: programs-overview.
                                                             (line  329)
* environment variable, MYSQL_UNIX_PORT <4>: environment-variables.
                                                             (line   18)
* environment variable, MYSQL_UNIX_PORT: mysql-install-db-problems.
                                                             (line   83)
* environment variable, PATH <1>:        invoking-programs.  (line   48)
* environment variable, PATH <2>:        environment-variables.
                                                             (line   18)
* environment variable, PATH:            unix-postinstallation.
                                                             (line   63)
* environment variable, TMPDIR <1>:      temporary-files.    (line    6)
* environment variable, TMPDIR <2>:      programs-overview.  (line  329)
* environment variable, TMPDIR <3>:      environment-variables.
                                                             (line   18)
* environment variable, TMPDIR:          mysql-install-db-problems.
                                                             (line   83)
* environment variable, TZ <1>:          timezone-problems.  (line    6)
* environment variable, TZ:              environment-variables.
                                                             (line   18)
* environment variable, UMASK <1>:       file-permissions.   (line    6)
* environment variable, UMASK:           environment-variables.
                                                             (line   18)
* environment variable, UMASK_DIR <1>:   file-permissions.   (line   20)
* environment variable, UMASK_DIR:       environment-variables.
                                                             (line   18)
* environment variable, USER <1>:        connecting.         (line  231)
* environment variable, USER:            environment-variables.
                                                             (line   18)
* environment variables <1>:             access-denied.      (line  101)
* environment variables <2>:             setting-environment-variables.
                                                             (line    6)
* environment variables:                 programs-overview.  (line  326)
* environment variables, CXX:            compilation-problems.
                                                             (line   75)
* environment variables, list of:        environment-variables.
                                                             (line    6)
* eq_ref join type, optimizer:           explain-output.     (line  215)
* equal (=):                             comparison-operators.
                                                             (line   64)
* Equals():                              functions-that-test-spatial-relationships-between-geometries.
                                                             (line   45)
* Errcode:                               perror.             (line    6)
* errno:                                 perror.             (line    6)
* ERROR Events (MySQL Cluster):          mysql-cluster-log-events.
                                                             (line  199)
* error logs (MySQL Cluster):            mysql-cluster-programs-ndbd.
                                                             (line  266)
* error messages, can't find file:       file-permissions.   (line    6)
* error messages, displaying:            perror.             (line    6)
* error messages, languages:             error-message-language.
                                                             (line    6)
* Error, thread command:                 thread-commands.    (line   50)
* error_count session variable:          server-system-variables.
                                                             (line 1521)
* ERROR_FOR_DIVISION_BY_ZERO SQL mode:   server-sql-mode.    (line  103)
* errors, access denied:                 error-access-denied.
                                                             (line    6)
* errors, and replication:               replication-features-slaveerrors.
                                                             (line    6)
* errors, checking tables for:           myisam-check.       (line    6)
* errors, common:                        problems.           (line   17)
* errors, directory checksum:            solaris.            (line   11)
* errors, handling for UDFs:             udf-return-values.  (line    6)
* errors, in subqueries:                 subquery-errors.    (line    6)
* errors, known:                         bugs.               (line    6)
* errors, linking:                       c-api-linking-problems.
                                                             (line    6)
* errors, list of:                       common-errors.      (line   28)
* errors, lost connection:               error-lost-connection.
                                                             (line    6)
* errors, reporting <1>:                 bug-reports.        (line    6)
* errors, reporting:                     introduction.       (line   76)
* errors, sources of information:        error-sources.      (line    6)
* escape (\\):                           string-literals.    (line   76)
* escape sequences, option files:        option-files.       (line  161)
* escape sequences, strings:             string-literals.    (line    6)
* estimating, query performance:         estimating-performance.
                                                             (line    6)
* event groups:                          set-global-sql-slave-skip-counter.
                                                             (line    6)
* event log format (MySQL Cluster):      mysql-cluster-log-events.
                                                             (line    6)
* event logs (MySQL Cluster) <1>:        mysql-cluster-logging-management-commands.
                                                             (line    6)
* event logs (MySQL Cluster):            mysql-cluster-event-reports.
                                                             (line   12)
* event severity levels (MySQL Cluster): mysql-cluster-logging-management-commands.
                                                             (line   55)
* event types (MySQL Cluster) <1>:       mysql-cluster-log-events.
                                                             (line   20)
* event types (MySQL Cluster):           mysql-cluster-event-reports.
                                                             (line   49)
* exact-value literals:                  precision-math.     (line   14)
* example option, mysqld_multi:          mysqld-multi.       (line  114)
* EXAMPLE storage engine <1>:            example-storage-engine.
                                                             (line    6)
* EXAMPLE storage engine:                storage-engines.    (line   19)
* examples, compressed tables:           myisampack.         (line  122)
* examples, myisamchk output:            myisamchk-table-info.
                                                             (line    6)
* examples, queries:                     examples.           (line   18)
* exe-suffix option, make_win_bin_dist:  make-win-bin-dist.  (line   46)
* EXECUTE <1>:                           execute.            (line    6)
* EXECUTE:                               sql-syntax-prepared-statements.
                                                             (line   12)
* execute option, mysql:                 mysql-command-options.
                                                             (line  236)
* Execute, thread command:               thread-commands.    (line   52)
* ExecuteOnComputer <1>:                 mysql-cluster-api-definition.
                                                             (line   69)
* ExecuteOnComputer <2>:                 mysql-cluster-ndbd-definition.
                                                             (line   79)
* ExecuteOnComputer:                     mysql-cluster-mgm-definition.
                                                             (line   59)
* executing SQL statements from text files <1>: batch-commands.
                                                             (line    6)
* executing SQL statements from text files: batch-mode.      (line    6)
* executing, thread state:               general-thread-states.
                                                             (line  117)
* Execution of init_command, thread state: general-thread-states.
                                                             (line  121)
* EXISTS, with subqueries:               exists-and-not-exists-subqueries.
                                                             (line    6)
* EXIT command (MySQL Cluster):          mysql-cluster-mgm-client-commands.
                                                             (line  114)
* exit command, mysql:                   mysql-commands.     (line  135)
* EXIT SINGLE USER MODE command (MySQL Cluster): mysql-cluster-mgm-client-commands.
                                                             (line  104)
* exit-info option, mysqld:              server-options.     (line  596)
* EXP():                                 mathematical-functions.
                                                             (line  197)
* expire_logs_days system variable:      server-system-variables.
                                                             (line 1527)
* EXPLAIN <1>:                           explain.            (line    6)
* EXPLAIN:                               using-explain.      (line    6)
* explicit default values:               data-type-defaults. (line    6)
* EXPORT_SET():                          string-functions.   (line  248)
* expression aliases <1>:                select.             (line  106)
* expression aliases:                    group-by-hidden-columns.
                                                             (line   80)
* expression syntax:                     expressions.        (line    6)
* expressions, extended:                 pattern-matching.   (line    6)
* extend-check option, myisamchk <1>:    myisamchk-repair-options.
                                                             (line   28)
* extend-check option, myisamchk:        myisamchk-check-options.
                                                             (line   18)
* extended option, mysqlcheck:           mysqlcheck.         (line  245)
* extended-insert option, mysqldump:     mysqldump.          (line  493)
* extensions, to standard SQL:           compatibility.      (line   15)
* ExteriorRing():                        polygon-property-functions.
                                                             (line   21)
* external locking <1>:                  general-thread-states.
                                                             (line  312)
* external locking <2>:                  external-locking.   (line    6)
* external locking <3>:                  myisam-crash-recovery.
                                                             (line    6)
* external locking <4>:                  server-system-variables.
                                                             (line 4461)
* external locking:                      server-options.     (line  613)
* external-locking option, mysqld:       server-options.     (line  613)
* extra-file option, my_print_defaults:  my-print-defaults.  (line   43)
* extra-partition-info option, ndb_desc: mysql-cluster-programs-ndb-desc.
                                                             (line   72)
* EXTRACT():                             date-and-time-functions.
                                                             (line  527)
* extracting, dates:                     date-calculations.  (line    6)
* FALSE <1>:                             boolean-literals.   (line    6)
* FALSE:                                 number-literals.    (line    6)
* FALSE, testing for:                    comparison-operators.
                                                             (line  130)
* fast option, myisamchk:                myisamchk-check-options.
                                                             (line   35)
* fast option, mysqlcheck:               mysqlcheck.         (line  254)
* fatal signal 11:                       compilation-problems.
                                                             (line   37)
* features of MySQL:                     features.           (line    6)
* FEDERATED storage engine <1>:          federated-storage-engine.
                                                             (line   12)
* FEDERATED storage engine:              storage-engines.    (line   19)
* FETCH:                                 fetch.              (line    6)
* Fetch, thread command:                 thread-commands.    (line   56)
* Field List, thread command:            thread-commands.    (line   61)
* FIELD():                               string-functions.   (line  266)
* field, changing:                       alter-table.        (line  241)
* fields option, ndb_config:             mysql-cluster-programs-ndb-config.
                                                             (line  204)
* fields-enclosed-by option, mysqldump <1>: mysqlimport.     (line  152)
* fields-enclosed-by option, mysqldump:  mysqldump.          (line  501)
* fields-escaped-by option, mysqldump <1>: mysqlimport.      (line  156)
* fields-escaped-by option, mysqldump:   mysqldump.          (line  505)
* fields-optionally-enclosed-by option, mysqldump <1>: mysqlimport.
                                                             (line  154)
* fields-optionally-enclosed-by option, mysqldump: mysqldump.
                                                             (line  503)
* fields-terminated-by option, mysqldump <1>: mysqlimport.   (line  150)
* fields-terminated-by option, mysqldump: mysqldump.         (line  499)
* FILE:                                  string-functions.   (line  386)
* files, binary log:                     binary-log.         (line    6)
* files, config.cache:                   compilation-problems.
                                                             (line    6)
* files, error messages:                 error-message-language.
                                                             (line    6)
* files, general query log:              query-log.          (line    6)
* files, log <1>:                        log-file-maintenance.
                                                             (line    6)
* files, log:                            source-configuration-options.
                                                             (line    6)
* files, my.cnf:                         replication-features.
                                                             (line   37)
* files, not found message:              file-permissions.   (line    6)
* files, permissions:                    file-permissions.   (line    6)
* files, repairing:                      myisamchk-repair-options.
                                                             (line    6)
* files, script:                         batch-mode.         (line    6)
* files, size limits:                    table-size-limit.   (line    6)
* files, slow query log:                 slow-query-log.     (line    6)
* files, text <1>:                       mysqlimport.        (line    6)
* files, text:                           batch-commands.     (line    6)
* files, tmp:                            mysql-install-db-problems.
                                                             (line   70)
* files, update log (obsolete):          binary-log.         (line    6)
* filesort optimization:                 order-by-optimization.
                                                             (line  113)
* FileSystemPath:                        mysql-cluster-ndbd-definition.
                                                             (line  235)
* FIND_IN_SET():                         string-functions.   (line  285)
* Finished reading one binlog; switching to next binlog, thread state: master-thread-states.
                                                             (line   17)
* firewalls (software), and MySQL Cluster: mysql-cluster-security-networking-issues.
                                                             (line   98)
* first-slave option, mysqldump:         mysqldump.          (line  511)
* FIXED data type:                       numeric-type-overview.
                                                             (line  220)
* fixed-point arithmetic:                precision-math.     (line   14)
* FLOAT data type:                       numeric-type-overview.
                                                             (line  228)
* floating-point number:                 numeric-type-overview.
                                                             (line  274)
* floating-point values, and replication: replication-features-floatvalues.
                                                             (line    6)
* floats:                                number-literals.    (line    6)
* FLOOR():                               mathematical-functions.
                                                             (line  210)
* FLUSH:                                 flush.              (line    6)
* flush option, mysqld:                  server-options.     (line  639)
* flush system variable:                 server-system-variables.
                                                             (line 1555)
* flush tables:                          mysqladmin.         (line  183)
* FLUSH, and replication:                replication-features-flush.
                                                             (line    6)
* flush-logs option, mysqldump:          mysqldump.          (line  516)
* flush-privileges option, mysqldump:    mysqldump.          (line  528)
* flush_time system variable:            server-system-variables.
                                                             (line 1577)
* Flushing tables, thread state:         general-thread-states.
                                                             (line  132)
* flushlog option, mysqlhotcopy:         mysqlhotcopy.       (line  113)
* FOR UPDATE:                            select.             (line  345)
* FORCE INDEX <1>:                       optimizer-issues.   (line   27)
* FORCE INDEX:                           index-hints.        (line    6)
* FORCE KEY:                             index-hints.        (line    6)
* force option, myisamchk <1>:           myisamchk-repair-options.
                                                             (line   40)
* force option, myisamchk:               myisamchk-check-options.
                                                             (line   39)
* force option, myisampack:              myisampack.         (line   66)
* force option, mysql:                   mysql-command-options.
                                                             (line  243)
* force option, mysql_convert_table_format: mysql-convert-table-format.
                                                             (line   28)
* force option, mysql_install_db:        mysql-install-db.   (line   49)
* force option, mysql_upgrade:           mysql-upgrade.      (line  113)
* force option, mysqladmin:              mysqladmin.         (line  316)
* force option, mysqlcheck:              mysqlcheck.         (line  258)
* force option, mysqldump:               mysqldump.          (line  536)
* force option, mysqlimport:             mysqlimport.        (line  161)
* force-read option, mysqlbinlog:        mysqlbinlog.        (line  225)
* foreign key, constraint:               constraint-primary-key.
                                                             (line    6)
* foreign key, deleting <1>:             innodb-foreign-key-constraints.
                                                             (line  162)
* foreign key, deleting:                 alter-table.        (line  351)
* foreign keys <1>:                      alter-table.        (line  333)
* foreign keys <2>:                      example-foreign-keys.
                                                             (line    6)
* foreign keys:                          ansi-diff-foreign-keys.
                                                             (line    6)
* foreign_key_checks session variable:   server-system-variables.
                                                             (line 1606)
* FORMAT():                              string-functions.   (line  300)
* Forums:                                forums.             (line    6)
* FOUND_ROWS():                          information-functions.
                                                             (line  192)
* FreeBSD troubleshooting:               compilation-problems.
                                                             (line  136)
* freeing items, thread state:           general-thread-states.
                                                             (line  126)
* frequently-asked questions about DRBD <1>: faqs-drbd.      (line    6)
* frequently-asked questions about DRBD: faqs-mysql-drbd-heartbeat.
                                                             (line   19)
* frequently-asked questions about MySQL Cluster: faqs-mysql-cluster.
                                                             (line    6)
* FROM:                                  select.             (line  134)
* FROM_DAYS():                           date-and-time-functions.
                                                             (line  543)
* FROM_UNIXTIME():                       date-and-time-functions.
                                                             (line  554)
* ft_boolean_syntax system variable:     server-system-variables.
                                                             (line 1627)
* ft_max_word_len myisamchk variable:    myisamchk-general-options.
                                                             (line   53)
* ft_max_word_len system variable:       server-system-variables.
                                                             (line 1664)
* ft_min_word_len myisamchk variable:    myisamchk-general-options.
                                                             (line   53)
* ft_min_word_len system variable:       server-system-variables.
                                                             (line 1689)
* ft_query_expansion_limit system variable: server-system-variables.
                                                             (line 1715)
* ft_stopword_file myisamchk variable:   myisamchk-general-options.
                                                             (line   53)
* ft_stopword_file system variable:      server-system-variables.
                                                             (line 1737)
* full disk:                             full-disk.          (line    6)
* full-text search:                      fulltext-search.    (line   16)
* FULLTEXT:                              fulltext-search.    (line   16)
* FULLTEXT initialization, thread state: general-thread-states.
                                                             (line  137)
* fulltext join type, optimizer:         explain-output.     (line  258)
* fulltext, stopword list:               fulltext-fine-tuning.
                                                             (line   40)
* function names, parsing:               function-resolution.
                                                             (line    6)
* function names, resolving ambiguity:   function-resolution.
                                                             (line    6)
* function, creating:                    create-function-udf.
                                                             (line    6)
* function, deleting:                    drop-function-udf.  (line    6)
* functions:                             functions.          (line   26)
* functions for SELECT and WHERE clauses: functions.         (line   26)
* functions, and replication:            replication-features-functions.
                                                             (line    6)
* functions, arithmetic:                 bit-functions.      (line    6)
* functions, bit:                        bit-functions.      (line    6)
* functions, C API:                      c-api-function-overview.
                                                             (line    6)
* functions, C prepared statement API <1>: c-api-prepared-statement-function-overview.
                                                             (line    6)
* functions, C prepared statement API:   c-api-prepared-statement-type-conversions.
                                                             (line    6)
* functions, cast:                       cast-functions.     (line    6)
* functions, control flow:               control-flow-functions.
                                                             (line    6)
* functions, date and time:              date-and-time-functions.
                                                             (line    6)
* functions, encryption:                 encryption-functions.
                                                             (line    6)
* functions, GROUP BY:                   group-by-functions. (line    6)
* functions, grouping:                   operator-precedence.
                                                             (line   49)
* functions, information:                information-functions.
                                                             (line    6)
* functions, mathematical:               mathematical-functions.
                                                             (line   54)
* functions, miscellaneous:              miscellaneous-functions.
                                                             (line    6)
* functions, native, adding:             adding-native-function.
                                                             (line    6)
* functions, new:                        adding-functions.   (line   12)
* functions, stored:                     stored-routines.    (line   13)
* functions, string:                     string-functions.   (line   11)
* functions, string comparison:          string-comparison-functions.
                                                             (line    6)
* functions, user-defined:               adding-functions.   (line   12)
* Functions, user-defined <1>:           drop-function-udf.  (line    6)
* Functions, user-defined:               create-function-udf.
                                                             (line    6)
* functions, user-defined, adding:       adding-udf.         (line   15)
* gap lock, InnoDB <1>:                  innodb-next-key-locking.
                                                             (line    6)
* gap lock, InnoDB <2>:                  innodb-record-level-locks.
                                                             (line    6)
* gap lock, InnoDB <3>:                  innodb-transaction-model.
                                                             (line   65)
* gap lock, InnoDB:                      innodb-parameters.  (line  707)
* gb2312, gbk:                           faqs-cjk.           (line    6)
* gcc:                                   source-configuration-options.
                                                             (line  350)
* gci option, ndb_select_all:            mysql-cluster-programs-ndb-select-all.
                                                             (line   61)
* gdb option, mysqld:                    server-options.     (line  659)
* gdb, using:                            using-gdb-on-mysqld.
                                                             (line    6)
* general information:                   introduction.       (line   18)
* General Public License:                what-is-mysql.      (line   39)
* general query log:                     query-log.          (line    6)
* geographic feature:                    gis-introduction.   (line   27)
* GeomCollFromText():                    gis-wkt-functions.  (line   14)
* GeomCollFromWKB():                     gis-wkb-functions.  (line   17)
* geometry:                              gis-introduction.   (line   40)
* GEOMETRY data type:                    mysql-spatial-datatypes.
                                                             (line    6)
* GEOMETRYCOLLECTION data type:          mysql-spatial-datatypes.
                                                             (line    6)
* GeometryCollection():                  gis-mysql-specific-functions.
                                                             (line   31)
* GeometryCollectionFromText():          gis-wkt-functions.  (line   14)
* GeometryCollectionFromWKB():           gis-wkb-functions.  (line   17)
* GeometryFromText():                    gis-wkt-functions.  (line   20)
* GeometryFromWKB():                     gis-wkb-functions.  (line   23)
* GeometryN():                           geometrycollection-property-functions.
                                                             (line    8)
* GeometryType():                        general-geometry-property-functions.
                                                             (line   38)
* GeomFromText() <1>:                    functions-to-convert-geometries-between-formats.
                                                             (line   29)
* GeomFromText():                        gis-wkt-functions.  (line   20)
* GeomFromWKB() <1>:                     functions-to-convert-geometries-between-formats.
                                                             (line   36)
* GeomFromWKB():                         gis-wkb-functions.  (line   23)
* geospatial feature:                    gis-introduction.   (line   37)
* GET_FORMAT():                          date-and-time-functions.
                                                             (line  582)
* GET_LOCK():                            miscellaneous-functions.
                                                             (line   40)
* getting MySQL:                         getting-mysql.      (line    6)
* GIS <1>:                               gis-introduction.   (line    6)
* GIS:                                   spatial-extensions. (line   16)
* GLength() <1>:                         multilinestring-property-functions.
                                                             (line    8)
* GLength():                             linestring-property-functions.
                                                             (line   23)
* global privileges <1>:                 revoke.             (line    6)
* global privileges:                     grant.              (line    6)
* globalization:                         globalization.      (line   16)
* go command, mysql:                     mysql-commands.     (line  139)
* goals of MySQL:                        what-is-mysql.      (line   84)
* got handler lock, thread state:        delayed-insert-thread-states.
                                                             (line   26)
* got old table, thread state:           delayed-insert-thread-states.
                                                             (line   32)
* GRANT:                                 grant.              (line    6)
* GRANT statement:                       adding-users.       (line    6)
* grant tables, re-creating:             mysql-install-db-problems.
                                                             (line  103)
* grant tables, sorting <1>:             request-access.     (line   51)
* grant tables, sorting:                 connection-access.  (line  123)
* grant tables, structure:               grant-table-structure.
                                                             (line    6)
* grant tables, upgrading:               mysql-fix-privilege-tables.
                                                             (line    6)
* granting, privileges:                  grant.              (line    6)
* GRANTS:                                show-grants.        (line    6)
* greater than (>):                      comparison-operators.
                                                             (line  123)
* greater than or equal (>=):            comparison-operators.
                                                             (line  116)
* GREATEST():                            comparison-operators.
                                                             (line  241)
* GROUP BY:                              group-by-optimization.
                                                             (line   11)
* GROUP BY functions:                    group-by-functions. (line    6)
* GROUP BY, aliases in:                  group-by-hidden-columns.
                                                             (line   80)
* GROUP BY, extensions to standard SQL <1>: select.          (line  204)
* GROUP BY, extensions to standard SQL:  group-by-hidden-columns.
                                                             (line    6)
* GROUP_CONCAT():                        group-by-functions. (line  139)
* group_concat_max_len system variable:  server-system-variables.
                                                             (line 1769)
* grouping, expressions:                 operator-precedence.
                                                             (line   49)
* HANDLER:                               handler.            (line    6)
* Handlers:                              declare-handler.    (line    6)
* handling, errors:                      udf-return-values.  (line    6)
* Has read all relay log; waiting for the slave I/O thread to update it, thread state: slave-sql-thread-states.
                                                             (line   18)
* Has sent all binlog to slave; waiting for binlog to be updated, thread state: master-thread-states.
                                                             (line   22)
* have_archive system variable:          server-system-variables.
                                                             (line 1801)
* have_bdb system variable:              server-system-variables.
                                                             (line 1806)
* have_blackhole_engine system variable: server-system-variables.
                                                             (line 1811)
* have_compress system variable:         server-system-variables.
                                                             (line 1816)
* have_crypt system variable:            server-system-variables.
                                                             (line 1822)
* have_csv system variable:              server-system-variables.
                                                             (line 1827)
* have_example_engine system variable:   server-system-variables.
                                                             (line 1832)
* have_federated_engine system variable: server-system-variables.
                                                             (line 1837)
* have_geometry system variable:         server-system-variables.
                                                             (line 1842)
* have_innodb system variable:           server-system-variables.
                                                             (line 1846)
* have_isam system variable:             server-system-variables.
                                                             (line 1851)
* have_merge_engine system variable:     server-system-variables.
                                                             (line 1857)
* have_openssl system variable:          server-system-variables.
                                                             (line 1863)
* have_query_cache system variable:      server-system-variables.
                                                             (line 1868)
* have_raid system variable:             server-system-variables.
                                                             (line 1873)
* have_rtree_keys system variable:       server-system-variables.
                                                             (line 1879)
* have_ssl system variable:              server-system-variables.
                                                             (line 1884)
* have_symlink system variable:          server-system-variables.
                                                             (line 1894)
* HAVING:                                select.             (line  218)
* header option, ndb_select_all:         mysql-cluster-programs-ndb-select-all.
                                                             (line   39)
* header_file option, comp_err:          comp-err.           (line   44)
* HEAP storage engine <1>:               memory-storage-engine.
                                                             (line    6)
* HEAP storage engine:                   storage-engines.    (line   19)
* HeartbeatIntervalDbApi:                mysql-cluster-ndbd-definition.
                                                             (line 1390)
* HeartbeatIntervalDbDb:                 mysql-cluster-ndbd-definition.
                                                             (line 1362)
* HELP command (MySQL Cluster):          mysql-cluster-mgm-client-commands.
                                                             (line   20)
* help command, mysql:                   mysql-commands.     (line   51)
* help option, comp_err:                 comp-err.           (line   26)
* help option, make_win_src_distribution: make-win-src-distribution.
                                                             (line   20)
* help option, my_print_defaults:        my-print-defaults.  (line   25)
* help option, myisam_ftdump:            myisam-ftdump.      (line   58)
* HELP option, myisamchk:                myisamchk-general-options.
                                                             (line   16)
* help option, myisamchk:                myisamchk-general-options.
                                                             (line   11)
* help option, myisampack:               myisampack.         (line   47)
* help option, mysql:                    mysql-command-options.
                                                             (line  147)
* help option, mysql_convert_table_format: mysql-convert-table-format.
                                                             (line   24)
* help option, mysql_explain_log:        mysql-explain-log.  (line   25)
* help option, mysql_find_rows:          mysql-find-rows.    (line   31)
* help option, mysql_setpermission:      mysql-setpermission.
                                                             (line   29)
* help option, mysql_tableinfo:          mysql-tableinfo.    (line   78)
* help option, mysql_upgrade:            mysql-upgrade.      (line   99)
* help option, mysql_waitpid:            mysql-waitpid.      (line   27)
* help option, mysqlaccess:              mysqlaccess.        (line   67)
* help option, mysqladmin:               mysqladmin.         (line  286)
* help option, mysqlbinlog:              mysqlbinlog.        (line  142)
* help option, mysqlcheck:               mysqlcheck.         (line  177)
* help option, mysqld:                   server-options.     (line   70)
* help option, mysqld_multi:             mysqld-multi.       (line   96)
* help option, mysqld_safe:              mysqld-safe.        (line  129)
* help option, mysqldump:                mysqldump.          (line  330)
* help option, mysqldumpslow:            mysqldumpslow.      (line   45)
* help option, mysqlhotcopy:             mysqlhotcopy.       (line   80)
* help option, mysqlimport:              mysqlimport.        (line  116)
* help option, mysqlmanager:             instance-manager-command-options.
                                                             (line   24)
* help option, mysqlshow:                mysqlshow.          (line  102)
* help option, perror:                   perror.             (line   40)
* help option, resolve_stack_dump:       resolve-stack-dump. (line   21)
* help option, resolveip:                resolveip.          (line   15)
* HELP statement:                        help.               (line    6)
* HEX() <1>:                             mathematical-functions.
                                                             (line  229)
* HEX():                                 string-functions.   (line  314)
* hex-blob option, mysqldump:            mysqldump.          (line  554)
* hexadecimal literals:                  hexadecimal-literals.
                                                             (line    6)
* hexdump option, mysqlbinlog:           mysqlbinlog.        (line  232)
* HIGH_NOT_PRECEDENCE SQL mode:          server-sql-mode.    (line  113)
* HIGH_PRIORITY:                         select.             (line  364)
* hints:                                 extensions-to-ansi. (line    6)
* hints, index <1>:                      index-hints.        (line    6)
* hints, index:                          select.             (line  142)
* history of MySQL:                      history.            (line    6)
* HOME environment variable <1>:         mysql-history-file. (line    6)
* HOME environment variable:             environment-variables.
                                                             (line   18)
* host name caching:                     dns.                (line    6)
* host name resolution:                  dns.                (line    6)
* host name, default:                    connecting.         (line    6)
* host option:                           connecting.         (line  129)
* host option, mysql:                    mysql-command-options.
                                                             (line  247)
* host option, mysql_convert_table_format: mysql-convert-table-format.
                                                             (line   32)
* host option, mysql_explain_log:        mysql-explain-log.  (line   33)
* host option, mysql_setpermission:      mysql-setpermission.
                                                             (line   33)
* host option, mysql_tableinfo:          mysql-tableinfo.    (line   95)
* host option, mysqlaccess:              mysqlaccess.        (line   94)
* host option, mysqladmin:               mysqladmin.         (line  321)
* host option, mysqlbinlog:              mysqlbinlog.        (line  238)
* host option, mysqlcheck:               mysqlcheck.         (line  262)
* host option, mysqldump:                mysqldump.          (line  549)
* host option, mysqlhotcopy:             mysqlhotcopy.       (line  117)
* host option, mysqlimport:              mysqlimport.        (line  167)
* host option, mysqlshow:                mysqlshow.          (line  131)
* host option, ndb_config:               mysql-cluster-programs-ndb-config.
                                                             (line  126)
* host table:                            request-access.     (line  148)
* host table, sorting:                   request-access.     (line   51)
* Host*SciId* parameters:                mysql-cluster-sci-definition.
                                                             (line   52)
* host.frm, problems finding:            unix-postinstallation.
                                                             (line  217)
* HostName <1>:                          mysql-cluster-api-definition.
                                                             (line   83)
* HostName <2>:                          mysql-cluster-ndbd-definition.
                                                             (line   93)
* HostName:                              mysql-cluster-mgm-definition.
                                                             (line   88)
* HostName (MySQL Cluster):              mysql-cluster-security-networking-issues.
                                                             (line   40)
* hostname system variable:              server-system-variables.
                                                             (line 1901)
* HostName1 <1>:                         mysql-cluster-sci-definition.
                                                             (line  114)
* HostName1 <2>:                         mysql-cluster-shm-definition.
                                                             (line   53)
* HostName1:                             mysql-cluster-tcp-definition.
                                                             (line   64)
* HostName2 <1>:                         mysql-cluster-sci-definition.
                                                             (line  125)
* HostName2 <2>:                         mysql-cluster-shm-definition.
                                                             (line   64)
* HostName2:                             mysql-cluster-tcp-definition.
                                                             (line   75)
* HOUR():                                date-and-time-functions.
                                                             (line  619)
* howto option, mysqlaccess:             mysqlaccess.        (line   98)
* html option, mysql:                    mysql-command-options.
                                                             (line  251)
* i-am-a-dummy option, mysql:            mysql-command-options.
                                                             (line  435)
* i5/OS:                                 i5os-installation.  (line    6)
* IBM i5/OS:                             i5os-installation.  (line    6)
* icc, and MySQL Cluster support>:       porting.            (line   32)
* icc, MySQL builds:                     compiler-characteristics.
                                                             (line    6)
* Id <1>:                                mysql-cluster-api-definition.
                                                             (line   26)
* Id <2>:                                mysql-cluster-ndbd-definition.
                                                             (line   36)
* Id:                                    mysql-cluster-mgm-definition.
                                                             (line   16)
* id option, ndb_config:                 mysql-cluster-programs-ndb-config.
                                                             (line  155)
* ID, unique:                            getting-unique-id.  (line    6)
* identifiers:                           identifiers.        (line   12)
* identifiers, case sensitivity:         identifier-case-sensitivity.
                                                             (line    6)
* identifiers, quoting:                  identifiers.        (line   18)
* identity session variable:             server-system-variables.
                                                             (line 1916)
* idx option, mysql_tableinfo:           mysql-tableinfo.    (line   99)
* IF:                                    if-statement.       (line    6)
* IF():                                  control-flow-functions.
                                                             (line   49)
* IFNULL():                              control-flow-functions.
                                                             (line   85)
* IGNORE INDEX:                          index-hints.        (line    6)
* IGNORE KEY:                            index-hints.        (line    6)
* ignore option, mysqlimport:            mysqlimport.        (line  172)
* ignore-lines option, mysqlimport:      mysqlimport.        (line  176)
* ignore-spaces option, mysql:           mysql-command-options.
                                                             (line  255)
* ignore-table option, mysqldump:        mysqldump.          (line  562)
* IGNORE_SPACE SQL mode:                 server-sql-mode.    (line  129)
* implicit default values:               data-type-defaults. (line    6)
* IMPORT TABLESPACE <1>:                 innodb-multiple-tablespaces.
                                                             (line   59)
* IMPORT TABLESPACE:                     alter-table.        (line  362)
* importing, data <1>:                   mysqlimport.        (line    6)
* importing, data:                       batch-commands.     (line    6)
* IN <1>:                                any-in-some-subqueries.
                                                             (line    6)
* IN:                                    comparison-operators.
                                                             (line  258)
* in_file option, comp_err:              comp-err.           (line   48)
* include option, mysql_config:          mysql-config.       (line   20)
* increasing with replication, speed:    replication.        (line   13)
* increasing, performance:               replication-faq.    (line   27)
* incremental recovery:                  point-in-time-recovery.
                                                             (line   11)
* INDEX DIRECTORY, and replication:      replication-features-directory.
                                                             (line    6)
* index hints <1>:                       index-hints.        (line    6)
* index hints:                           select.             (line  142)
* index join type, optimizer:            explain-output.     (line  324)
* index, deleting <1>:                   drop-index.         (line    6)
* index, deleting:                       alter-table.        (line  248)
* index, rebuilding:                     rebuilding-tables.  (line    6)
* index-record lock, InnoDB <1>:         innodb-next-key-locking.
                                                             (line    6)
* index-record lock, InnoDB <2>:         innodb-record-level-locks.
                                                             (line    6)
* index-record lock, InnoDB <3>:         innodb-transaction-model.
                                                             (line   65)
* index-record lock, InnoDB:             innodb-parameters.  (line  707)
* index_merge join type, optimizer:      explain-output.     (line  275)
* index_subquery join type, optimizer:   explain-output.     (line  293)
* indexes:                               create-index.       (line    6)
* indexes, and BLOB columns <1>:         create-table.       (line  359)
* indexes, and BLOB columns:             column-indexes.     (line   15)
* indexes, and IS NULL:                  mysql-indexes.      (line  137)
* indexes, and LIKE:                     mysql-indexes.      (line  111)
* indexes, and NULL values:              create-table.       (line  338)
* indexes, and TEXT columns <1>:         create-table.       (line  359)
* indexes, and TEXT columns:             column-indexes.     (line   15)
* indexes, assigning to key cache:       cache-index.        (line    6)
* indexes, block size:                   server-system-variables.
                                                             (line 2093)
* indexes, columns:                      column-indexes.     (line    6)
* indexes, leftmost prefix of <1>:       mysql-indexes.      (line   88)
* indexes, leftmost prefix of:           multiple-column-indexes.
                                                             (line   81)
* indexes, multi-column:                 multiple-column-indexes.
                                                             (line    6)
* indexes, multiple-part:                create-index.       (line    6)
* indexes, names:                        identifiers.        (line   12)
* indexes, use of:                       mysql-indexes.      (line    6)
* IndexMemory <1>:                       mysql-cluster-config-lcp-params.
                                                             (line    6)
* IndexMemory:                           mysql-cluster-ndbd-definition.
                                                             (line  394)
* INET_ATON():                           miscellaneous-functions.
                                                             (line   96)
* INET_NTOA():                           miscellaneous-functions.
                                                             (line  122)
* INFO Events (MySQL Cluster):           mysql-cluster-log-events.
                                                             (line  213)
* information functions:                 information-functions.
                                                             (line    6)
* information option, myisamchk:         myisamchk-check-options.
                                                             (line   45)
* INFORMATION_SCHEMA:                    information-schema. (line   28)
* INFORMATION_SCHEMA, and security issues: mysql-cluster-security-mysql-privileges.
                                                             (line  112)
* Init DB, thread command:               thread-commands.    (line   65)
* init, thread state:                    general-thread-states.
                                                             (line  142)
* init-file option, mysqld:              server-options.     (line  676)
* init_connect system variable:          server-system-variables.
                                                             (line 1923)
* init_file system variable:             server-system-variables.
                                                             (line 1964)
* init_slave system variable:            replication-options-slave.
                                                             (line 1057)
* INNER JOIN:                            join.               (line    6)
* innochecksum <1>:                      innochecksum.       (line    6)
* innochecksum:                          programs-overview.  (line  167)
* InnoDB:                                innodb-storage-engine.
                                                             (line   23)
* InnoDB buffer pool:                    innodb-buffer-pool. (line    6)
* innodb option, mysqld:                 innodb-parameters.  (line  112)
* InnoDB storage engine <1>:             innodb-storage-engine.
                                                             (line   23)
* InnoDB storage engine:                 storage-engines.    (line   19)
* InnoDB tables:                         ansi-diff-transactions.
                                                             (line    6)
* InnoDB, backups:                       innodb-backup.      (line   12)
* InnoDB, clustered index:               innodb-index-types. (line    6)
* InnoDB, gap lock <1>:                  innodb-next-key-locking.
                                                             (line    6)
* InnoDB, gap lock <2>:                  innodb-record-level-locks.
                                                             (line    6)
* InnoDB, gap lock <3>:                  innodb-transaction-model.
                                                             (line   65)
* InnoDB, gap lock:                      innodb-parameters.  (line  707)
* InnoDB, index-record lock <1>:         innodb-next-key-locking.
                                                             (line    6)
* InnoDB, index-record lock <2>:         innodb-record-level-locks.
                                                             (line    6)
* InnoDB, index-record lock <3>:         innodb-transaction-model.
                                                             (line   65)
* InnoDB, index-record lock:             innodb-parameters.  (line  707)
* InnoDB, limits and restrictions:       innodb-restrictions.
                                                             (line    6)
* InnoDB, Monitors <1>:                  innodb-troubleshooting-datadict.
                                                             (line   57)
* InnoDB, Monitors <2>:                  innodb-troubleshooting.
                                                             (line   26)
* InnoDB, Monitors <3>:                  innodb-monitors.    (line   12)
* InnoDB, Monitors <4>:                  innodb-file-space.  (line   48)
* InnoDB, Monitors:                      innodb-backup.      (line  110)
* InnoDB, next-key lock <1>:             innodb-next-key-locking.
                                                             (line    6)
* InnoDB, next-key lock <2>:             innodb-record-level-locks.
                                                             (line    6)
* InnoDB, next-key lock <3>:             innodb-transaction-model.
                                                             (line   65)
* InnoDB, next-key lock:                 innodb-parameters.  (line  707)
* InnoDB, NFS <1>:                       innodb-restrictions.
                                                             (line   16)
* InnoDB, NFS:                           innodb-configuration.
                                                             (line   50)
* InnoDB, page size <1>:                 innodb-restrictions.
                                                             (line   71)
* InnoDB, page size:                     innodb-physical-structure.
                                                             (line    6)
* InnoDB, record-level locks <1>:        innodb-next-key-locking.
                                                             (line    6)
* InnoDB, record-level locks <2>:        innodb-record-level-locks.
                                                             (line    6)
* InnoDB, record-level locks <3>:        innodb-transaction-model.
                                                             (line   65)
* InnoDB, record-level locks:            innodb-parameters.  (line  707)
* InnoDB, secondary index:               innodb-index-types. (line    6)
* InnoDB, Solaris 10 x86_64 issues:      solaris.            (line   11)
* InnoDB, transaction isolation levels:  innodb-transaction-model.
                                                             (line   53)
* innodb-safe-binlog option, mysqld:     server-options.     (line  700)
* innodb-status-file option, mysqld:     innodb-parameters.  (line  123)
* INSERT <1>:                            insert.             (line   12)
* INSERT:                                insert-speed.       (line    6)
* INSERT ... SELECT:                     insert-select.      (line    6)
* INSERT DELAYED:                        insert-delayed.     (line    6)
* INSERT statement, grant privileges:    adding-users.       (line  116)
* INSERT():                              string-functions.   (line  332)
* insert, thread state:                  delayed-insert-thread-states.
                                                             (line   74)
* insert-ignore option, mysqldump:       mysqldump.          (line  569)
* insert_id session variable:            server-system-variables.
                                                             (line 1996)
* insertable views, insertable:          view-updatability.  (line    6)
* inserting, speed of:                   insert-speed.       (line    6)
* inserts, concurrent <1>:               concurrent-inserts. (line    6)
* inserts, concurrent:                   internal-locking.   (line   73)
* install option, mysqld:                server-options.     (line  726)
* install option, mysqlmanager:          instance-manager-command-options.
                                                             (line   67)
* install-manual option, mysqld:         server-options.     (line  737)
* installation layouts:                  installation-layouts.
                                                             (line    6)
* installation overview:                 source-installation.
                                                             (line   14)
* installing MySQL Cluster:              mysql-cluster-installation.
                                                             (line   15)
* installing MySQL Cluster, Linux:       mysql-cluster-install-linux.
                                                             (line   12)
* installing MySQL Cluster, Linux binary release: mysql-cluster-install-linux-binary.
                                                             (line    6)
* installing MySQL Cluster, Linux RPM:   mysql-cluster-install-linux-rpm.
                                                             (line    6)
* installing MySQL Cluster, Linux source release: mysql-cluster-install-linux-source.
                                                             (line    6)
* installing, binary distribution:       binary-installation.
                                                             (line    6)
* installing, Linux RPM packages:        linux-installation-rpm.
                                                             (line    6)
* installing, Mac OS X PKG packages:     macosx-installation.
                                                             (line    6)
* installing, MySQL Community Server:    installing-cs.      (line   12)
* installing, MySQL Enterprise:          installing-es.      (line   11)
* installing, overview <1>:              installation-overview.
                                                             (line    6)
* installing, overview:                  installing.         (line   31)
* installing, Perl:                      perl-support.       (line   12)
* installing, Perl on Windows:           activestate-perl.   (line    6)
* installing, Solaris PKG packages:      solaris-installation.
                                                             (line    6)
* installing, source distribution:       source-installation.
                                                             (line   14)
* installing, user-defined functions:    udf-compiling.      (line    6)
* INSTR():                               string-functions.   (line  350)
* INT data type:                         numeric-type-overview.
                                                             (line  121)
* integer arithmetic:                    precision-math.     (line   14)
* INTEGER data type:                     numeric-type-overview.
                                                             (line  126)
* integers:                              number-literals.    (line    6)
* interactive_timeout system variable:   server-system-variables.
                                                             (line 2002)
* InteriorRingN():                       polygon-property-functions.
                                                             (line   35)
* internal compiler errors:              compilation-problems.
                                                             (line   37)
* internal locking:                      internal-locking.   (line    6)
* internals:                             mysql-internals.    (line   11)
* internationalization:                  globalization.      (line   16)
* Internet Relay Chat:                   irc.                (line    6)
* Intersection():                        spatial-operators.  (line   26)
* Intersects():                          functions-that-test-spatial-relationships-between-geometries.
                                                             (line   49)
* INTERVAL():                            comparison-operators.
                                                             (line  318)
* INTO, SELECT:                          select-into.        (line    6)
* introducer, string literal <1>:        charset-literal.    (line   11)
* introducer, string literal:            string-literals.    (line   33)
* invalid data, constraint:              constraint-invalid-data.
                                                             (line    6)
* invalidating query cache entries, thread state: query-cache-thread-states.
                                                             (line   19)
* IRC:                                   irc.                (line    6)
* IS boolean_value:                      comparison-operators.
                                                             (line  130)
* IS NOT boolean_value:                  comparison-operators.
                                                             (line  140)
* IS NOT NULL:                           comparison-operators.
                                                             (line  192)
* IS NULL <1>:                           comparison-operators.
                                                             (line  150)
* IS NULL:                               is-null-optimization.
                                                             (line    6)
* IS NULL, and indexes:                  mysql-indexes.      (line  137)
* IS_FREE_LOCK():                        miscellaneous-functions.
                                                             (line  132)
* IS_USED_LOCK():                        miscellaneous-functions.
                                                             (line  139)
* isamlog <1>:                           myisamlog.          (line    6)
* isamlog:                               programs-overview.  (line  182)
* IsClosed():                            multilinestring-property-functions.
                                                             (line   25)
* IsEmpty():                             general-geometry-property-functions.
                                                             (line   75)
* ISNULL():                              comparison-operators.
                                                             (line  301)
* ISOLATION LEVEL:                       set-transaction.    (line    6)
* IsRing():                              linestring-property-functions.
                                                             (line   80)
* IsSimple():                            general-geometry-property-functions.
                                                             (line   81)
* ITERATE:                               iterate-statement.  (line    6)
* Japanese character sets, conversion:   faqs-cjk.           (line    6)
* Japanese, Korean, Chinese character sets, frequently asked questions: faqs-cjk.
                                                             (line    6)
* JOIN:                                  join.               (line    6)
* join algorithm, Block Nested-Loop:     nested-loop-joins.  (line    6)
* join algorithm, Nested-Loop:           nested-loop-joins.  (line    6)
* join option, myisampack:               myisampack.         (line   78)
* join type, ALL:                        explain-output.     (line  333)
* join type, const:                      explain-output.     (line  198)
* join type, eq_ref:                     explain-output.     (line  215)
* join type, fulltext:                   explain-output.     (line  258)
* join type, index:                      explain-output.     (line  324)
* join type, index_merge:                explain-output.     (line  275)
* join type, index_subquery:             explain-output.     (line  293)
* join type, range:                      explain-output.     (line  301)
* join type, ref:                        explain-output.     (line  236)
* join type, ref_or_null:                explain-output.     (line  262)
* join type, system:                     explain-output.     (line  193)
* join type, unique_subquery:            explain-output.     (line  283)
* join, nested-loop algorithm:           nested-join-optimization.
                                                             (line  172)
* join_buffer_size system variable:      server-system-variables.
                                                             (line 2027)
* keep_files_on_create system variable:  server-system-variables.
                                                             (line 2058)
* keepold option, mysqlhotcopy:          mysqlhotcopy.       (line  123)
* key cache, assigning indexes to:       cache-index.        (line    6)
* Key cache, MyISAM:                     myisam-key-cache.   (line   15)
* key space, MyISAM:                     key-space.          (line    6)
* key_buffer_size myisamchk variable:    myisamchk-general-options.
                                                             (line   53)
* key_buffer_size system variable:       server-system-variables.
                                                             (line 2093)
* key_cache_age_threshold system variable: server-system-variables.
                                                             (line 2168)
* key_cache_block_size system variable:  server-system-variables.
                                                             (line 2203)
* key_cache_division_limit system variable: server-system-variables.
                                                             (line 2226)
* KEY_COLUMN_USAGE, INFORMATION_SCHEMA table: key-column-usage-table.
                                                             (line    6)
* keys:                                  column-indexes.     (line    6)
* keys option, mysqlshow:                mysqlshow.          (line  135)
* keys, foreign <1>:                     example-foreign-keys.
                                                             (line    6)
* keys, foreign:                         ansi-diff-foreign-keys.
                                                             (line    6)
* keys, multi-column:                    multiple-column-indexes.
                                                             (line    6)
* keys, searching on two:                searching-on-two-keys.
                                                             (line    6)
* keys-used option, myisamchk:           myisamchk-repair-options.
                                                             (line   45)
* keywords:                              reserved-words.     (line    6)
* KILL:                                  kill.               (line    6)
* Kill, thread command:                  thread-commands.    (line   69)
* Killed, thread state:                  general-thread-states.
                                                             (line  158)
* Killing slave, thread state:           slave-connection-thread-states.
                                                             (line   21)
* known errors:                          bugs.               (line    6)
* Korean:                                faqs-cjk.           (line    6)
* Korean, Chinese, Japanese character sets, frequently asked questions: faqs-cjk.
                                                             (line    6)
* labels, stored program block:          statement-labels.   (line    6)
* language option, mysqld:               server-options.     (line  749)
* language support, error messages:      error-message-language.
                                                             (line    6)
* language system variable:              server-system-variables.
                                                             (line 2250)
* large page support:                    large-page-support. (line    6)
* large-pages option, mysqld:            server-options.     (line  774)
* large_files_support system variable:   server-system-variables.
                                                             (line 2273)
* large_page_size system variable:       server-system-variables.
                                                             (line 2309)
* large_pages system variable:           server-system-variables.
                                                             (line 2283)
* last row, unique ID:                   getting-unique-id.  (line    6)
* LAST_DAY():                            date-and-time-functions.
                                                             (line  631)
* last_insert_id session variable:       server-system-variables.
                                                             (line 2330)
* LAST_INSERT_ID() <1>:                  insert.             (line  206)
* LAST_INSERT_ID():                      ansi-diff-transactions.
                                                             (line  160)
* LAST_INSERT_ID() and stored routines:  stored-routines-last-insert-id.
                                                             (line    6)
* LAST_INSERT_ID() and triggers:         stored-routines-last-insert-id.
                                                             (line    6)
* LAST_INSERT_ID(), and replication:     replication-features-auto-increment.
                                                             (line    6)
* LAST_INSERT_ID([<replaceable>expr</replaceable>]): information-functions.
                                                             (line  275)
* layout of installation:                installation-layouts.
                                                             (line    6)
* lc_time_names system variable:         server-system-variables.
                                                             (line 2338)
* LCASE():                               string-functions.   (line  364)
* LD_LIBRARY_PATH environment variable:  perl-support-problems.
                                                             (line   23)
* LD_RUN_PATH environment variable <1>:  perl-support-problems.
                                                             (line   23)
* LD_RUN_PATH environment variable <2>:  environment-variables.
                                                             (line   18)
* LD_RUN_PATH environment variable <3>:  solaris.            (line  145)
* LD_RUN_PATH environment variable:      source-notes-linux. (line   98)
* ldata option, mysql_install_db:        mysql-install-db.   (line   55)
* LDML syntax:                           ldml-rules.         (line    6)
* LEAST():                               comparison-operators.
                                                             (line  332)
* LEAVE:                                 leave-statement.    (line    6)
* ledir option, mysqld_safe:             mysqld-safe.        (line  171)
* LEFT JOIN <1>:                         join.               (line    6)
* LEFT JOIN:                             left-join-optimization.
                                                             (line    6)
* LEFT OUTER JOIN:                       join.               (line    6)
* LEFT():                                string-functions.   (line  368)
* leftmost prefix of indexes <1>:        mysql-indexes.      (line   88)
* leftmost prefix of indexes:            multiple-column-indexes.
                                                             (line   81)
* legal names:                           identifiers.        (line   12)
* length option, myisam_ftdump:          myisam-ftdump.      (line   70)
* LENGTH():                              string-functions.   (line  376)
* less than (<):                         comparison-operators.
                                                             (line  109)
* less than or equal (<=):               comparison-operators.
                                                             (line  102)
* libmysqld:                             libmysqld.          (line    6)
* libmysqld-libs option, mysql_config:   mysql-config.       (line   24)
* library, mysqlclient:                  connectors-apis.    (line   23)
* library, mysqld:                       connectors-apis.    (line   23)
* libs option, mysql_config:             mysql-config.       (line   29)
* libs_r option, mysql_config:           mysql-config.       (line   34)
* license system variable:               server-system-variables.
                                                             (line 2360)
* LIKE:                                  string-comparison-functions.
                                                             (line   20)
* LIKE, and indexes:                     mysql-indexes.      (line  111)
* LIKE, and wildcards:                   mysql-indexes.      (line  111)
* LIMIT <1>:                             select.             (line  285)
* LIMIT <2>:                             information-functions.
                                                             (line  192)
* LIMIT:                                 limit-optimization. (line    6)
* LIMIT, and replication:                replication-features-limit.
                                                             (line    6)
* limitations of MySQL Cluster:          mysql-cluster-limitations.
                                                             (line   19)
* limitations, design:                   design-limitations. (line    6)
* limitations, MySQL Limitations:        limits.             (line   14)
* limitations, replication:              replication-features.
                                                             (line   37)
* limits, file-size:                     table-size-limit.   (line    6)
* limits, MySQL Limits, limits in MySQL: limits.             (line   14)
* line-numbers option, mysql:            mysql-command-options.
                                                             (line  261)
* linefeed (\n) <1>:                     load-data.          (line  416)
* linefeed (\n):                         string-literals.    (line   72)
* LineFromText():                        gis-wkt-functions.  (line   25)
* LineFromWKB():                         gis-wkb-functions.  (line   28)
* lines-terminated-by option, mysqldump <1>: mysqlimport.    (line  180)
* lines-terminated-by option, mysqldump: mysqldump.          (line  574)
* LINESTRING data type:                  mysql-spatial-datatypes.
                                                             (line    6)
* LineString():                          gis-mysql-specific-functions.
                                                             (line   35)
* LineStringFromText():                  gis-wkt-functions.  (line   25)
* LineStringFromWKB():                   gis-wkb-functions.  (line   28)
* linking:                               building-clients.   (line   11)
* linking, errors:                       c-api-linking-problems.
                                                             (line    6)
* linking, problems:                     c-api-linking-problems.
                                                             (line    6)
* linking, speed:                        compile-and-link-options.
                                                             (line    6)
* links, symbolic:                       symbolic-links.     (line   12)
* Linux, binary distribution:            binary-notes-linux. (line    6)
* Linux, source distribution:            source-notes-linux. (line    6)
* literals:                              literals.           (line   16)
* LN():                                  mathematical-functions.
                                                             (line  236)
* LOAD DATA FROM MASTER:                 load-data-from-master.
                                                             (line    6)
* LOAD DATA INFILE <1>:                  problems-with-null. (line   51)
* LOAD DATA INFILE:                      load-data.          (line    6)
* LOAD DATA, and replication:            replication-features-load.
                                                             (line    6)
* LOAD TABLE FROM MASTER:                load-table-from-master.
                                                             (line    6)
* LOAD TABLE FROM MASTER, and replication: replication-features-load.
                                                             (line    6)
* LOAD_FILE():                           string-functions.   (line  386)
* loading, tables:                       loading-tables.     (line    6)
* local checkpoints (MySQL Cluster):     mysql-cluster-config-lcp-params.
                                                             (line    6)
* local option, mysqlimport:             mysqlimport.        (line  189)
* local-infile option, mysql:            mysql-command-options.
                                                             (line  266)
* local-infile option, mysqld:           privileges-options. (line   51)
* local-load option, mysqlbinlog:        mysqlbinlog.        (line  242)
* local_infile system variable:          server-system-variables.
                                                             (line 2374)
* localhost, special treatment of:       connecting.         (line   75)
* localization:                          globalization.      (line   16)
* localstatedir option, configure:       source-configuration-options.
                                                             (line  302)
* LOCALTIME:                             date-and-time-functions.
                                                             (line  646)
* LOCALTIMESTAMP:                        date-and-time-functions.
                                                             (line  650)
* LOCATE():                              string-functions.   (line  407)
* LOCK IN SHARE MODE:                    select.             (line  345)
* Lock Monitor, InnoDB:                  innodb-monitors.    (line   12)
* lock option, ndb_select_all:           mysql-cluster-programs-ndb-select-all.
                                                             (line   15)
* LOCK TABLES:                           lock-tables.        (line   12)
* lock-all-tables option, mysqldump:     mysqldump.          (line  580)
* lock-tables option, mysqldump:         mysqldump.          (line  587)
* lock-tables option, mysqlimport:       mysqlimport.        (line  193)
* Locked, thread state:                  general-thread-states.
                                                             (line  167)
* locked_in_memory system variable:      server-system-variables.
                                                             (line 2388)
* locking:                               system-optimization.
                                                             (line   24)
* locking methods:                       internal-locking.   (line    6)
* locking, external <1>:                 general-thread-states.
                                                             (line  312)
* locking, external <2>:                 external-locking.   (line    6)
* locking, external <3>:                 myisam-crash-recovery.
                                                             (line    6)
* locking, external <4>:                 server-system-variables.
                                                             (line 4461)
* locking, external:                     server-options.     (line  613)
* locking, internal:                     internal-locking.   (line    6)
* locking, page-level:                   internal-locking.   (line    6)
* locking, row-level <1>:                internal-locking.   (line    6)
* locking, row-level:                    ansi-diff-transactions.
                                                             (line  168)
* locking, table-level:                  internal-locking.   (line    6)
* LockPagesInMainMemory:                 mysql-cluster-ndbd-definition.
                                                             (line 1138)
* log files:                             source-configuration-options.
                                                             (line    6)
* log files (MySQL Cluster):             mysql-cluster-programs-ndbd.
                                                             (line  257)
* log files, maintaining:                log-file-maintenance.
                                                             (line    6)
* log option, mysqld:                    server-options.     (line  807)
* log option, mysqld_multi:              mysqld-multi.       (line  118)
* log option, mysqlmanager:              instance-manager-command-options.
                                                             (line   73)
* log system variable:                   server-system-variables.
                                                             (line 2398)
* LOG():                                 mathematical-functions.
                                                             (line  250)
* log, changes <1>:                      news-5-0-x.         (line  115)
* log, changes:                          news.               (line   17)
* log-bin option, mysqld:                replication-options-binary-log.
                                                             (line   20)
* log-bin-index option, mysqld:          replication-options-binary-log.
                                                             (line   50)
* log-bin-trust-function-creators option, mysqld: replication-options-binary-log.
                                                             (line   67)
* log-bin-trust-routine-creators option, mysqld: replication-options-binary-log.
                                                             (line   94)
* log-error option, mysqld:              server-options.     (line  832)
* log-error option, mysqld_safe:         mysqld-safe.        (line  177)
* log-error option, mysqldump:           mysqldump.          (line  601)
* log-isam option, mysqld:               server-options.     (line  854)
* log-long-format option, mysqld:        server-options.     (line  869)
* log-queries-not-using-indexes option, mysqld: server-options.
                                                             (line  887)
* log-short-format option, mysqld:       server-options.     (line  911)
* log-slave-updates option, mysqld:      replication-options-slave.
                                                             (line  164)
* log-slow-admin-statements option, mysqld: server-options.  (line  927)
* log-slow-queries option, mysqld:       server-options.     (line  943)
* log-tc option, mysqld:                 server-options.     (line  967)
* log-tc-size option, mysqld:            server-options.     (line  987)
* log-warnings option, mysqld <1>:       replication-options-slave.
                                                             (line  199)
* log-warnings option, mysqld:           server-options.     (line 1012)
* LOG10():                               mathematical-functions.
                                                             (line  290)
* LOG2():                                mathematical-functions.
                                                             (line  277)
* log_bin system variable:               server-system-variables.
                                                             (line 2403)
* log_bin_trust_function_creators system variable: server-system-variables.
                                                             (line 2418)
* log_bin_trust_routine_creators system variable: server-system-variables.
                                                             (line 2451)
* log_error system variable:             server-system-variables.
                                                             (line 2461)
* log_queries_not_using_indexes system variable: server-system-variables.
                                                             (line 2480)
* log_slow_queries system variable:      server-system-variables.
                                                             (line 2501)
* log_warnings system variable:          server-system-variables.
                                                             (line 2524)
* LogDestination:                        mysql-cluster-mgm-definition.
                                                             (line  104)
* logging commands (MySQL Cluster):      mysql-cluster-logging-management-commands.
                                                             (line    6)
* logging slow query, thread state:      general-thread-states.
                                                             (line  171)
* logical operators:                     logical-operators.  (line    6)
* login, thread state:                   general-thread-states.
                                                             (line  180)
* LogLevelCheckpoint:                    mysql-cluster-ndbd-definition.
                                                             (line 1883)
* LogLevelCongestion:                    mysql-cluster-ndbd-definition.
                                                             (line 1952)
* LogLevelConnection:                    mysql-cluster-ndbd-definition.
                                                             (line 1917)
* LogLevelError:                         mysql-cluster-ndbd-definition.
                                                             (line 1934)
* LogLevelInfo:                          mysql-cluster-ndbd-definition.
                                                             (line 1971)
* LogLevelNodeRestart:                   mysql-cluster-ndbd-definition.
                                                             (line 1901)
* LogLevelShutdown:                      mysql-cluster-ndbd-definition.
                                                             (line 1848)
* LogLevelStartup:                       mysql-cluster-ndbd-definition.
                                                             (line 1831)
* LogLevelStatistic:                     mysql-cluster-ndbd-definition.
                                                             (line 1865)
* logs, and TIMESTAMP:                   upgrading-from-previous-series.
                                                             (line  329)
* logs, flushing:                        server-logs.        (line   32)
* logs, server:                          server-logs.        (line   14)
* LONG data type:                        blob.               (line    6)
* Long Data, thread command:             thread-commands.    (line   73)
* long_query_time system variable:       server-system-variables.
                                                             (line 2553)
* LONGBLOB data type:                    string-type-overview.
                                                             (line  257)
* LongMessageBuffer:                     mysql-cluster-ndbd-definition.
                                                             (line  835)
* LONGTEXT data type:                    string-type-overview.
                                                             (line  267)
* LOOP:                                  loop-statement.     (line    6)
* LOOP, labels:                          statement-labels.   (line    6)
* loops option, ndb_show_tables:         mysql-cluster-programs-ndb-show-tables.
                                                             (line   40)
* lost connection errors:                error-lost-connection.
                                                             (line    6)
* low-priority option, mysqlimport:      mysqlimport.        (line  198)
* low-priority-updates option, mysqld:   server-options.     (line 1051)
* low_priority_updates system variable:  server-system-variables.
                                                             (line 2581)
* LOWER():                               string-functions.   (line  424)
* lower_case_file_system system variable: server-system-variables.
                                                             (line 2607)
* lower_case_table_names system variable: server-system-variables.
                                                             (line 2629)
* LPAD():                                string-functions.   (line  448)
* LTRIM():                               string-functions.   (line  459)
* Mac OS X:                              connector-odbc.     (line   17)
* Mac OS X, installation:                macosx-installation.
                                                             (line    6)
* mailing list address:                  introduction.       (line   76)
* mailing lists:                         mailing-lists.      (line   10)
* mailing lists, archive location:       mailing-lists.      (line   10)
* mailing lists, guidelines:             mailing-list-use.   (line    6)
* main features of MySQL:                features.           (line    6)
* maintaining, log files:                log-file-maintenance.
                                                             (line    6)
* maintaining, tables:                   myisam-maintenance-schedule.
                                                             (line    6)
* maintenance, tables:                   mysqlcheck.         (line    6)
* make_binary_distribution:              programs-overview.  (line   75)
* MAKE_SET():                            string-functions.   (line  468)
* make_win_bin_dist <1>:                 make-win-bin-dist.  (line    6)
* make_win_bin_dist:                     programs-overview.  (line   81)
* make_win_bin_dist, debug option:       make-win-bin-dist.  (line   36)
* make_win_bin_dist, embedded option:    make-win-bin-dist.  (line   41)
* make_win_bin_dist, exe-suffix option:  make-win-bin-dist.  (line   46)
* make_win_bin_dist, no-debug option:    make-win-bin-dist.  (line   52)
* make_win_bin_dist, no-embedded option: make-win-bin-dist.  (line   56)
* make_win_bin_dist, only-debug option:  make-win-bin-dist.  (line   60)
* make_win_src_distribution <1>:         make-win-src-distribution.
                                                             (line    6)
* make_win_src_distribution <2>:         programs-overview.  (line  123)
* make_win_src_distribution:             windows-sourcetree-build.
                                                             (line    6)
* make_win_src_distribution, debug option: make-win-src-distribution.
                                                             (line   24)
* make_win_src_distribution, dirname option: make-win-src-distribution.
                                                             (line   28)
* make_win_src_distribution, help option: make-win-src-distribution.
                                                             (line   20)
* make_win_src_distribution, silent option: make-win-src-distribution.
                                                             (line   32)
* make_win_src_distribution, suffix option: make-win-src-distribution.
                                                             (line   36)
* make_win_src_distribution, tar option: make-win-src-distribution.
                                                             (line   40)
* make_win_src_distribution, tmp option: make-win-src-distribution.
                                                             (line   49)
* MAKEDATE():                            date-and-time-functions.
                                                             (line  654)
* MAKETIME():                            date-and-time-functions.
                                                             (line  666)
* Making temp file, thread state:        slave-sql-thread-states.
                                                             (line   25)
* malicious SQL statements, and MySQL Cluster: mysql-cluster-security-mysql-privileges.
                                                             (line   80)
* management client (MySQL Cluster):     mysql-cluster-programs-ndb-mgm.
                                                             (line    6)
* management node (MySQL Cluster), defined: mysql-cluster-basics.
                                                             (line    6)
* management nodes (MySQL Cluster):      mysql-cluster-programs-ndb-mgmd.
                                                             (line    6)
* managing MySQL Cluster:                mysql-cluster-management.
                                                             (line   18)
* managing MySQL Cluster processes:      mysql-cluster-programs.
                                                             (line   30)
* manual, available formats:             manual-info.        (line   32)
* manual, online location:               manual-info.        (line    6)
* manual, syntax conventions:            manual-conventions. (line    8)
* manual, typographical conventions:     manual-conventions. (line    8)
* master-connect-retry option, mysqld:   replication-options-slave.
                                                             (line  235)
* master-data option, mysqldump:         mysqldump.          (line  606)
* master-host option, mysqld:            replication-options-slave.
                                                             (line  257)
* master-info-file option, mysqld:       replication-options-slave.
                                                             (line  273)
* master-password option, mysqld:        replication-options-slave.
                                                             (line  291)
* master-port option, mysqld:            replication-options-slave.
                                                             (line  308)
* master-retry-count option, mysqld:     replication-options-slave.
                                                             (line  325)
* master-ssl option, mysqld:             replication-options-slave.
                                                             (line  358)
* master-ssl-ca option, mysqld:          replication-options-slave.
                                                             (line  358)
* master-ssl-capath option, mysqld:      replication-options-slave.
                                                             (line  358)
* master-ssl-cert option, mysqld:        replication-options-slave.
                                                             (line  358)
* master-ssl-cipher option, mysqld:      replication-options-slave.
                                                             (line  358)
* master-ssl-key option, mysqld:         replication-options-slave.
                                                             (line  358)
* master-user option, mysqld:            replication-options-slave.
                                                             (line  370)
* MASTER_POS_WAIT() <1>:                 master-pos-wait.    (line    6)
* MASTER_POS_WAIT():                     miscellaneous-functions.
                                                             (line  145)
* MATCH ... AGAINST():                   fulltext-search.    (line   16)
* matching, patterns:                    pattern-matching.   (line    6)
* math:                                  precision-math.     (line   14)
* mathematical functions:                mathematical-functions.
                                                             (line   54)
* MAX():                                 group-by-functions. (line  197)
* MAX(DISTINCT):                         group-by-functions. (line  197)
* max-binlog-dump-events option, mysqld: replication-options-binary-log.
                                                             (line  241)
* max-record-length option, myisamchk:   myisamchk-repair-options.
                                                             (line   61)
* max-relay-log-size option, mysqld:     replication-options-slave.
                                                             (line  389)
* max_allowed_packet system variable:    server-system-variables.
                                                             (line 2676)
* max_allowed_packet variable:           mysql-command-options.
                                                             (line  585)
* max_binlog_cache_size system variable: replication-options-binary-log.
                                                             (line  285)
* max_binlog_size system variable:       replication-options-binary-log.
                                                             (line  307)
* max_connect_errors system variable:    server-system-variables.
                                                             (line 2723)
* max_connections system variable:       server-system-variables.
                                                             (line 2760)
* MAX_CONNECTIONS_PER_HOUR:              user-resources.     (line    6)
* max_delayed_threads system variable:   server-system-variables.
                                                             (line 2780)
* max_error_count system variable:       server-system-variables.
                                                             (line 2811)
* max_heap_table_size system variable:   server-system-variables.
                                                             (line 2835)
* max_insert_delayed_threads system variable: server-system-variables.
                                                             (line 2880)
* max_join_size system variable:         server-system-variables.
                                                             (line 2894)
* max_join_size variable:                mysql-command-options.
                                                             (line  590)
* max_length_for_sort_data system variable: server-system-variables.
                                                             (line 2935)
* max_prepared_stmt_count system variable: server-system-variables.
                                                             (line 2958)
* MAX_QUERIES_PER_HOUR:                  user-resources.     (line    6)
* max_relay_log_size system variable:    server-system-variables.
                                                             (line 2990)
* MAX_ROWS, and MySQL Cluster:           create-table.       (line  629)
* max_seeks_for_key system variable:     server-system-variables.
                                                             (line 3020)
* max_sort_length system variable:       server-system-variables.
                                                             (line 3057)
* max_sp_recursion_depth system variable: server-system-variables.
                                                             (line 3081)
* max_tmp_tables system variable:        server-system-variables.
                                                             (line 3113)
* MAX_UPDATES_PER_HOUR:                  user-resources.     (line    6)
* MAX_USER_CONNECTIONS:                  user-resources.     (line    6)
* max_user_connections system variable:  server-system-variables.
                                                             (line 3145)
* max_write_lock_count system variable:  server-system-variables.
                                                             (line 3186)
* MAXDB SQL mode:                        server-sql-mode.    (line  411)
* maximum memory used:                   mysqladmin.         (line  198)
* maximums, maximum columns per table:   column-count-limit. (line    6)
* maximums, maximum number of databases: database-count-limit.
                                                             (line    6)
* maximums, maximum number of tables:    database-count-limit.
                                                             (line    6)
* maximums, maximum tables per join:     joins-limits.       (line    6)
* maximums, table size:                  table-size-limit.   (line    6)
* MaxNoOfAttributes:                     mysql-cluster-ndbd-definition.
                                                             (line  952)
* MaxNoOfConcurrentIndexOperations:      mysql-cluster-ndbd-definition.
                                                             (line  672)
* MaxNoOfConcurrentOperations:           mysql-cluster-ndbd-definition.
                                                             (line  576)
* MaxNoOfConcurrentScans:                mysql-cluster-ndbd-definition.
                                                             (line  765)
* MaxNoOfConcurrentTransactions:         mysql-cluster-ndbd-definition.
                                                             (line  531)
* MaxNoOfFiredTriggers:                  mysql-cluster-ndbd-definition.
                                                             (line  699)
* MaxNoOfIndexes:                        mysql-cluster-ndbd-definition.
                                                             (line 1120)
* MaxNoOfLocalOperations:                mysql-cluster-ndbd-definition.
                                                             (line  639)
* MaxNoOfLocalScans:                     mysql-cluster-ndbd-definition.
                                                             (line  799)
* MaxNoOfOpenFiles:                      mysql-cluster-ndbd-definition.
                                                             (line  914)
* MaxNoOfOrderedIndexes:                 mysql-cluster-ndbd-definition.
                                                             (line 1044)
* MaxNoOfSavedMessages:                  mysql-cluster-ndbd-definition.
                                                             (line  925)
* MaxNoOfTables:                         mysql-cluster-ndbd-definition.
                                                             (line 1004)
* MaxNoOfTriggers:                       mysql-cluster-ndbd-definition.
                                                             (line 1097)
* MaxNoOfUniqueHashIndexes:              mysql-cluster-ndbd-definition.
                                                             (line 1071)
* MaxScanBatchSize:                      mysql-cluster-api-definition.
                                                             (line  172)
* MBR:                                   relations-on-geometry-mbr.
                                                             (line    6)
* MBRContains():                         relations-on-geometry-mbr.
                                                             (line   10)
* MBRDisjoint():                         relations-on-geometry-mbr.
                                                             (line   25)
* MBREqual():                            relations-on-geometry-mbr.
                                                             (line   30)
* MBRIntersects():                       relations-on-geometry-mbr.
                                                             (line   35)
* MBROverlaps():                         relations-on-geometry-mbr.
                                                             (line   40)
* MBRTouches():                          relations-on-geometry-mbr.
                                                             (line   48)
* MBRWithin():                           relations-on-geometry-mbr.
                                                             (line   56)
* MD5():                                 encryption-functions.
                                                             (line  272)
* medium-check option, myisamchk:        myisamchk-check-options.
                                                             (line   49)
* medium-check option, mysqlcheck:       mysqlcheck.         (line  266)
* MEDIUMBLOB data type:                  string-type-overview.
                                                             (line  241)
* MEDIUMINT data type:                   numeric-type-overview.
                                                             (line  116)
* MEDIUMTEXT data type:                  string-type-overview.
                                                             (line  248)
* memlock option, mysqld:                server-options.     (line 1078)
* MEMORY storage engine <1>:             memory-storage-engine.
                                                             (line    6)
* MEMORY storage engine:                 storage-engines.    (line   19)
* MEMORY storage engine, and replication: replication-features-memory.
                                                             (line    6)
* memory usage, myisamchk:               myisamchk-memory.   (line    6)
* memory use <1>:                        memory-use.         (line    6)
* memory use:                            mysqladmin.         (line  192)
* memory use, in MySQL Cluster:          mysql-cluster-limitations-limits.
                                                             (line    9)
* MERGE storage engine <1>:              merge-storage-engine.
                                                             (line   11)
* MERGE storage engine:                  storage-engines.    (line   19)
* MERGE tables, defined:                 merge-storage-engine.
                                                             (line   11)
* metadata, database:                    information-schema. (line   28)
* metadata, stored routines:             stored-routines-metadata.
                                                             (line    6)
* metadata, triggers:                    trigger-metadata.   (line    6)
* metadata, views:                       view-metadata.      (line    6)
* method option, mysqlhotcopy:           mysqlhotcopy.       (line  127)
* methods, locking:                      internal-locking.   (line    6)
* mgmd (MySQL Cluster), defined:         mysql-cluster-basics.
                                                             (line    6)
* MICROSECOND():                         date-and-time-functions.
                                                             (line  674)
* Microsoft Access:                      connector-odbc-usagenotes-apptips-microsoft-access.
                                                             (line    6)
* Microsoft ADO:                         connector-odbc-usagenotes-apptips-microsoft-ado.
                                                             (line    6)
* Microsoft Excel:                       connector-odbc-usagenotes-apptips-microsoft-excel.
                                                             (line    6)
* Microsoft Visual Basic:                connector-odbc-usagenotes-apptips-microsoft-visualbasic.
                                                             (line    6)
* Microsoft Visual InterDev:             connector-odbc-usagenotes-apptips-microsoft-visualinterdev.
                                                             (line    6)
* MID():                                 string-functions.   (line  485)
* MIN():                                 group-by-functions. (line  217)
* MIN(DISTINCT):                         group-by-functions. (line  217)
* Minimum Bounding Rectangle:            relations-on-geometry-mbr.
                                                             (line    6)
* minus, unary (-):                      arithmetic-functions.
                                                             (line   69)
* MINUTE():                              date-and-time-functions.
                                                             (line  684)
* mirror sites:                          getting-mysql.      (line    6)
* miscellaneous functions:               miscellaneous-functions.
                                                             (line    6)
* MLineFromText():                       gis-wkt-functions.  (line   30)
* MLineFromWKB():                        gis-wkb-functions.  (line   33)
* MOD (modulo):                          mathematical-functions.
                                                             (line  303)
* MOD():                                 mathematical-functions.
                                                             (line  303)
* modes, batch:                          batch-mode.         (line    6)
* modulo (%):                            mathematical-functions.
                                                             (line  303)
* modulo (MOD):                          mathematical-functions.
                                                             (line  303)
* monitor, terminal:                     tutorial.           (line   16)
* monitoring-interval option, mysqlmanager: instance-manager-command-options.
                                                             (line   91)
* Monitors, InnoDB <1>:                  innodb-troubleshooting-datadict.
                                                             (line   57)
* Monitors, InnoDB <2>:                  innodb-troubleshooting.
                                                             (line   26)
* Monitors, InnoDB <3>:                  innodb-monitors.    (line   12)
* Monitors, InnoDB <4>:                  innodb-file-space.  (line   48)
* Monitors, InnoDB:                      innodb-backup.      (line  110)
* Mono:                                  connector-net.      (line   18)
* MONTH():                               date-and-time-functions.
                                                             (line  691)
* MONTHNAME():                           date-and-time-functions.
                                                             (line  700)
* MPointFromText():                      gis-wkt-functions.  (line   35)
* MPointFromWKB():                       gis-wkb-functions.  (line   38)
* MPolyFromText():                       gis-wkt-functions.  (line   40)
* MPolyFromWKB():                        gis-wkb-functions.  (line   43)
* mSQL compatibility:                    regexp.             (line   32)
* msql2mysql:                            msql2mysql.         (line    6)
* MSSQL SQL mode:                        server-sql-mode.    (line  417)
* multi mysqld:                          mysqld-multi.       (line    6)
* multi-byte character sets:             cannot-initialize-character-set.
                                                             (line    6)
* multi-byte characters:                 multi-byte-characters.
                                                             (line    6)
* multi-column indexes:                  multiple-column-indexes.
                                                             (line    6)
* MULTILINESTRING data type:             mysql-spatial-datatypes.
                                                             (line    6)
* MultiLineString():                     gis-mysql-specific-functions.
                                                             (line   41)
* MultiLineStringFromText():             gis-wkt-functions.  (line   30)
* MultiLineStringFromWKB():              gis-wkb-functions.  (line   33)
* multiple servers:                      multiple-servers.   (line   13)
* multiple-part index:                   create-index.       (line    6)
* multiplication (*):                    arithmetic-functions.
                                                             (line   83)
* MULTIPOINT data type:                  mysql-spatial-datatypes.
                                                             (line    6)
* MultiPoint():                          gis-mysql-specific-functions.
                                                             (line   46)
* MultiPointFromText():                  gis-wkt-functions.  (line   35)
* MultiPointFromWKB():                   gis-wkb-functions.  (line   38)
* MULTIPOLYGON data type:                mysql-spatial-datatypes.
                                                             (line    6)
* MultiPolygon():                        gis-mysql-specific-functions.
                                                             (line   51)
* MultiPolygonFromText():                gis-wkt-functions.  (line   40)
* MultiPolygonFromWKB():                 gis-wkb-functions.  (line   43)
* My, derivation:                        history.            (line    6)
* my.cnf file:                           replication-features.
                                                             (line   37)
* my.cnf, and MySQL Cluster <1>:         mysql-cluster-config-example.
                                                             (line    6)
* my.cnf, and MySQL Cluster <2>:         mysql-cluster-config-file.
                                                             (line   20)
* my.cnf, and MySQL Cluster:             mysql-cluster-install-configuration.
                                                             (line    6)
* my.cnf, in MySQL Cluster:              mysql-cluster-programs-mysqld.
                                                             (line   39)
* my_bool C type:                        c-api-data-structures.
                                                             (line   64)
* my_bool values, printing:              c-api-data-structures.
                                                             (line   64)
* my_init():                             my-init.            (line    6)
* my_print_defaults <1>:                 my-print-defaults.  (line    6)
* my_print_defaults:                     programs-overview.  (line  279)
* my_print_defaults, config-file option: my-print-defaults.  (line   29)
* my_print_defaults, debug option:       my-print-defaults.  (line   35)
* my_print_defaults, defaults-extra-file option: my-print-defaults.
                                                             (line   41)
* my_print_defaults, defaults-file option: my-print-defaults.
                                                             (line   31)
* my_print_defaults, defaults-group-suffix option: my-print-defaults.
                                                             (line   48)
* my_print_defaults, extra-file option:  my-print-defaults.  (line   43)
* my_print_defaults, help option:        my-print-defaults.  (line   25)
* my_print_defaults, no-defaults option: my-print-defaults.  (line   53)
* my_print_defaults, verbose option:     my-print-defaults.  (line   57)
* my_print_defaults, version option:     my-print-defaults.  (line   61)
* my_ulonglong C type:                   c-api-data-structures.
                                                             (line   50)
* my_ulonglong values, printing:         c-api-data-structures.
                                                             (line   50)
* mycnf option, ndb_config:              mysql-cluster-programs-ndb-config.
                                                             (line   84)
* mycnf option, ndb_mgmd:                mysql-cluster-programs-ndb-mgmd.
                                                             (line   74)
* MyISAM key cache:                      myisam-key-cache.   (line   15)
* MyISAM storage engine <1>:             myisam-storage-engine.
                                                             (line   13)
* MyISAM storage engine:                 storage-engines.    (line   19)
* MyISAM, compressed tables <1>:         compressed-format.  (line    6)
* MyISAM, compressed tables:             myisampack.         (line    6)
* myisam-block-size option, mysqld:      server-options.     (line 1122)
* myisam-recover option, mysqld <1>:     myisam-start.       (line   38)
* myisam-recover option, mysqld:         server-options.     (line 1139)
* myisam_block_size myisamchk variable:  myisamchk-general-options.
                                                             (line   53)
* myisam_data_pointer_size system variable: server-system-variables.
                                                             (line 3217)
* myisam_ftdump <1>:                     myisam-ftdump.      (line    6)
* myisam_ftdump:                         programs-overview.  (line  172)
* myisam_ftdump, count option:           myisam-ftdump.      (line   62)
* myisam_ftdump, dump option:            myisam-ftdump.      (line   66)
* myisam_ftdump, help option:            myisam-ftdump.      (line   58)
* myisam_ftdump, length option:          myisam-ftdump.      (line   70)
* myisam_ftdump, stats option:           myisam-ftdump.      (line   74)
* myisam_ftdump, verbose option:         myisam-ftdump.      (line   79)
* myisam_max_extra_sort_file_size system variable: server-system-variables.
                                                             (line 3251)
* myisam_max_sort_file_size system variable: server-system-variables.
                                                             (line 3255)
* myisam_mmap_size system variable:      server-system-variables.
                                                             (line 3284)
* myisam_recover_options system variable: server-system-variables.
                                                             (line 3319)
* myisam_repair_threads system variable: server-system-variables.
                                                             (line 3329)
* myisam_sort_buffer_size system variable: server-system-variables.
                                                             (line 3366)
* myisam_stats_method system variable:   server-system-variables.
                                                             (line 3403)
* myisamchk <1>:                         myisamchk.          (line   15)
* myisamchk:                             programs-overview.  (line  177)
* myisamchk, analyze option:             myisamchk-other-options.
                                                             (line    9)
* myisamchk, backup option:              myisamchk-repair-options.
                                                             (line   10)
* myisamchk, block-search option:        myisamchk-other-options.
                                                             (line   18)
* myisamchk, character-sets-dir option:  myisamchk-repair-options.
                                                             (line   14)
* myisamchk, check option:               myisamchk-check-options.
                                                             (line    9)
* myisamchk, check-only-changed option:  myisamchk-check-options.
                                                             (line   14)
* myisamchk, correct-checksum option:    myisamchk-repair-options.
                                                             (line   19)
* myisamchk, data-file-length option:    myisamchk-repair-options.
                                                             (line   23)
* myisamchk, debug option:               myisamchk-general-options.
                                                             (line   21)
* myisamchk, description option:         myisamchk-other-options.
                                                             (line   22)
* myisamchk, example output:             myisamchk-table-info.
                                                             (line    6)
* myisamchk, extend-check option <1>:    myisamchk-repair-options.
                                                             (line   28)
* myisamchk, extend-check option:        myisamchk-check-options.
                                                             (line   18)
* myisamchk, fast option:                myisamchk-check-options.
                                                             (line   35)
* myisamchk, force option <1>:           myisamchk-repair-options.
                                                             (line   40)
* myisamchk, force option:               myisamchk-check-options.
                                                             (line   39)
* myisamchk, HELP option:                myisamchk-general-options.
                                                             (line   16)
* myisamchk, help option:                myisamchk-general-options.
                                                             (line   11)
* myisamchk, information option:         myisamchk-check-options.
                                                             (line   45)
* myisamchk, keys-used option:           myisamchk-repair-options.
                                                             (line   45)
* myisamchk, max-record-length option:   myisamchk-repair-options.
                                                             (line   61)
* myisamchk, medium-check option:        myisamchk-check-options.
                                                             (line   49)
* myisamchk, no-symlinks option:         myisamchk-repair-options.
                                                             (line   54)
* myisamchk, options:                    myisamchk-general-options.
                                                             (line    6)
* myisamchk, parallel-recover option:    myisamchk-repair-options.
                                                             (line   66)
* myisamchk, quick option:               myisamchk-repair-options.
                                                             (line   72)
* myisamchk, read-only option:           myisamchk-check-options.
                                                             (line   55)
* myisamchk, recover option:             myisamchk-repair-options.
                                                             (line   79)
* myisamchk, safe-recover option:        myisamchk-repair-options.
                                                             (line   92)
* myisamchk, set-auto-increment[ option: myisamchk-other-options.
                                                             (line   28)
* myisamchk, set-character-set option:   myisamchk-repair-options.
                                                             (line  105)
* myisamchk, set-collation option:       myisamchk-repair-options.
                                                             (line  110)
* myisamchk, silent option:              myisamchk-general-options.
                                                             (line   27)
* myisamchk, sort-index option:          myisamchk-other-options.
                                                             (line   36)
* myisamchk, sort-records option:        myisamchk-other-options.
                                                             (line   41)
* myisamchk, sort-recover option:        myisamchk-repair-options.
                                                             (line  116)
* myisamchk, tmpdir option:              myisamchk-repair-options.
                                                             (line  121)
* myisamchk, unpack option:              myisamchk-repair-options.
                                                             (line  131)
* myisamchk, update-state option:        myisamchk-check-options.
                                                             (line   62)
* myisamchk, verbose option:             myisamchk-general-options.
                                                             (line   32)
* myisamchk, version option:             myisamchk-general-options.
                                                             (line   38)
* myisamchk, wait option:                myisamchk-general-options.
                                                             (line   42)
* myisamlog <1>:                         myisamlog.          (line    6)
* myisamlog:                             programs-overview.  (line  182)
* myisampack <1>:                        compressed-format.  (line    6)
* myisampack <2>:                        silent-column-changes.
                                                             (line  111)
* myisampack <3>:                        myisampack.         (line    6)
* myisampack:                            programs-overview.  (line  187)
* myisampack, backup option:             myisampack.         (line   51)
* myisampack, character-sets-dir option: myisampack.         (line   56)
* myisampack, debug option:              myisampack.         (line   61)
* myisampack, force option:              myisampack.         (line   66)
* myisampack, help option:               myisampack.         (line   47)
* myisampack, join option:               myisampack.         (line   78)
* myisampack, silent option:             myisampack.         (line   93)
* myisampack, test option:               myisampack.         (line   97)
* myisampack, tmpdir option:             myisampack.         (line  101)
* myisampack, verbose option:            myisampack.         (line  106)
* myisampack, version option:            myisampack.         (line  111)
* myisampack, wait option:               myisampack.         (line  115)
* MyODBC:                                connector-odbc.     (line   17)
* mysql <1>:                             mysql.              (line   15)
* mysql:                                 programs-overview.  (line  132)
* mysql \. (command for reading from text files) <1>: batch-commands.
                                                             (line    6)
* mysql \. (command for reading from text files): batch-mode.
                                                             (line   90)
* MySQL binary distribution:             which-version.      (line   19)
* MYSQL C type:                          c-api-data-structures.
                                                             (line   10)
* MySQL Cluster:                         mysql-cluster.      (line   14)
* MySQL Cluster How-To:                  mysql-cluster-installation.
                                                             (line   15)
* MySQL Cluster limitations:             mysql-cluster-limitations.
                                                             (line   19)
* MySQL Cluster limitations, and differences from standard MySQL limits: mysql-cluster-limitations-limits.
                                                             (line    6)
* MySQL Cluster limitations, binary logging: mysql-cluster-limitations-exclusive-to-cluster.
                                                             (line   50)
* MySQL Cluster limitations, database objects: mysql-cluster-limitations-database-objects.
                                                             (line    6)
* MySQL Cluster limitations, error handling and reporting: mysql-cluster-limitations-error-handling.
                                                             (line    6)
* MySQL Cluster limitations, geometry data types: mysql-cluster-limitations-syntax.
                                                             (line   86)
* MySQL Cluster limitations, implementation: mysql-cluster-limitations-exclusive-to-cluster.
                                                             (line    6)
* MySQL Cluster limitations, imposed by configuration: mysql-cluster-limitations-limits.
                                                             (line   35)
* MySQL Cluster limitations, INSERT IGNORE, UPDATE IGNORE, and REPLACE statements: mysql-cluster-limitations-resolved.
                                                             (line   37)
* MySQL Cluster limitations, memory usage and transaction handling: mysql-cluster-limitations-transactions.
                                                             (line  106)
* MySQL Cluster limitations, multiple management servers: mysql-cluster-limitations-multiple-nodes.
                                                             (line   56)
* MySQL Cluster limitations, multiple MySQL servers: mysql-cluster-limitations-multiple-nodes.
                                                             (line    8)
* MySQL Cluster limitations, performance: mysql-cluster-limitations-performance.
                                                             (line    6)
* MySQL Cluster limitations, resolved in current version from previous versions: mysql-cluster-limitations-resolved.
                                                             (line    6)
* MySQL Cluster limitations, syntax:     mysql-cluster-limitations-syntax.
                                                             (line    6)
* MySQL Cluster limitations, transactions: mysql-cluster-limitations-transactions.
                                                             (line    6)
* MySQL Cluster limitations, unsupported features: mysql-cluster-limitations-unsupported.
                                                             (line    6)
* MySQL Cluster processes:               mysql-cluster-programs.
                                                             (line   30)
* MySQL Cluster programs:                mysql-cluster-programs.
                                                             (line   30)
* MySQL Cluster, "quick" configuration:  mysql-cluster-quick.
                                                             (line    6)
* MySQL Cluster, administration <1>:     mysql-cluster-log-statistics.
                                                             (line    6)
* MySQL Cluster, administration <2>:     mysql-cluster-mgm-client-commands.
                                                             (line    6)
* MySQL Cluster, administration <3>:     mysql-cluster-program-options-common.
                                                             (line    6)
* MySQL Cluster, administration <4>:     mysql-cluster-programs-ndb-mgm.
                                                             (line    6)
* MySQL Cluster, administration <5>:     mysql-cluster-programs-ndb-mgmd.
                                                             (line   12)
* MySQL Cluster, administration <6>:     mysql-cluster-programs-ndbd.
                                                             (line   17)
* MySQL Cluster, administration:         mysql-cluster-program-options-mysqld.
                                                             (line    6)
* MySQL Cluster, and DNS:                mysql-cluster-installation.
                                                             (line   54)
* MySQL Cluster, and INFORMATION_SCHEMA: mysql-cluster-security-mysql-privileges.
                                                             (line  112)
* MySQL Cluster, and IP addressing:      mysql-cluster-installation.
                                                             (line   54)
* MySQL Cluster, and MySQL privileges:   mysql-cluster-security-mysql-privileges.
                                                             (line    6)
* MySQL Cluster, and MySQL root user <1>: mysql-cluster-security-mysql-security-procedures.
                                                             (line   49)
* MySQL Cluster, and MySQL root user:    mysql-cluster-security-mysql-privileges.
                                                             (line   48)
* MySQL Cluster, and networking:         mysql-cluster-overview-requirements.
                                                             (line    6)
* MySQL Cluster, and transactions:       faqs-mysql-cluster. (line    6)
* MySQL Cluster, and virtual machines:   faqs-mysql-cluster. (line    6)
* MySQL Cluster, API node <1>:           mysql-cluster-api-definition.
                                                             (line    6)
* MySQL Cluster, API node:               mysql-cluster-basics.
                                                             (line    6)
* MySQL Cluster, arbitrator:             faqs-mysql-cluster. (line    6)
* MySQL Cluster, available platforms:    mysql-cluster.      (line   22)
* MySQL Cluster, backups <1>:            mysql-cluster-backup-troubleshooting.
                                                             (line    6)
* MySQL Cluster, backups <2>:            mysql-cluster-backup-configuration.
                                                             (line    6)
* MySQL Cluster, backups <3>:            mysql-cluster-backup-using-management-client.
                                                             (line    6)
* MySQL Cluster, backups <4>:            mysql-cluster-backup-concepts.
                                                             (line    6)
* MySQL Cluster, backups <5>:            mysql-cluster-backup.
                                                             (line   13)
* MySQL Cluster, backups:                mysql-cluster-programs-ndb-restore.
                                                             (line    6)
* MySQL Cluster, benchmarks:             mysql-cluster-interconnects-performance.
                                                             (line    6)
* MySQL Cluster, CHECKPOINT Events:      mysql-cluster-log-events.
                                                             (line   35)
* MySQL Cluster, cluster logs <1>:       mysql-cluster-logging-management-commands.
                                                             (line    6)
* MySQL Cluster, cluster logs:           mysql-cluster-event-reports.
                                                             (line   12)
* MySQL Cluster, CLUSTERLOG commands:    mysql-cluster-logging-management-commands.
                                                             (line    8)
* MySQL Cluster, CLUSTERLOG STATISTICS command: mysql-cluster-log-statistics.
                                                             (line    6)
* MySQL Cluster, commands <1>:           mysql-cluster-mgm-client-commands.
                                                             (line    6)
* MySQL Cluster, commands <2>:           mysql-cluster-programs-ndb-mgm.
                                                             (line   27)
* MySQL Cluster, commands <3>:           mysql-cluster-programs-ndb-mgmd.
                                                             (line   12)
* MySQL Cluster, commands <4>:           mysql-cluster-programs-ndbd.
                                                             (line   17)
* MySQL Cluster, commands:               mysql-cluster-program-options-mysqld.
                                                             (line    6)
* MySQL Cluster, compiling with icc:     porting.            (line   32)
* MySQL Cluster, concepts:               mysql-cluster-basics.
                                                             (line    6)
* MySQL Cluster, configuration <1>:      mysql-cluster-programs-ndb-mgmd.
                                                             (line  173)
* MySQL Cluster, configuration <2>:      mysql-cluster-programs-mysqld.
                                                             (line   39)
* MySQL Cluster, configuration <3>:      mysql-cluster-config-lcp-params.
                                                             (line    6)
* MySQL Cluster, configuration <4>:      mysql-cluster-api-definition.
                                                             (line    6)
* MySQL Cluster, configuration <5>:      mysql-cluster-ndbd-definition.
                                                             (line    6)
* MySQL Cluster, configuration <6>:      mysql-cluster-mgm-definition.
                                                             (line    6)
* MySQL Cluster, configuration <7>:      mysql-cluster-computer-definition.
                                                             (line    6)
* MySQL Cluster, configuration <8>:      mysql-cluster-quick.
                                                             (line    6)
* MySQL Cluster, configuration <9>:      mysql-cluster-configuration.
                                                             (line   14)
* MySQL Cluster, configuration:          mysql-cluster-installation.
                                                             (line   15)
* MySQL Cluster, configuration (example): mysql-cluster-config-example.
                                                             (line    6)
* MySQL Cluster, configuration changes:  mysql-cluster-rolling-restart.
                                                             (line   20)
* MySQL Cluster, configuration files <1>: mysql-cluster-config-file.
                                                             (line   20)
* MySQL Cluster, configuration files:    mysql-cluster-install-configuration.
                                                             (line    6)
* MySQL Cluster, configuration parameters <1>: mysql-cluster-params-other.
                                                             (line    6)
* MySQL Cluster, configuration parameters <2>: mysql-cluster-params-api.
                                                             (line    6)
* MySQL Cluster, configuration parameters <3>: mysql-cluster-params-mgmd.
                                                             (line    6)
* MySQL Cluster, configuration parameters <4>: mysql-cluster-params-ndbd.
                                                             (line    6)
* MySQL Cluster, configuration parameters: mysql-cluster-params-overview.
                                                             (line   13)
* MySQL Cluster, configuring:            mysql-cluster-backup-configuration.
                                                             (line    6)
* MySQL Cluster, CONNECTION Events:      mysql-cluster-log-events.
                                                             (line   20)
* MySQL Cluster, connectstring:          mysql-cluster-connectstring.
                                                             (line    6)
* MySQL Cluster, data node <1>:          mysql-cluster-ndbd-definition.
                                                             (line    6)
* MySQL Cluster, data node:              mysql-cluster-basics.
                                                             (line    6)
* MySQL Cluster, data nodes:             mysql-cluster-programs-ndbd.
                                                             (line    6)
* MySQL Cluster, data types supported:   faqs-mysql-cluster. (line    6)
* MySQL Cluster, defining node hosts:    mysql-cluster-computer-definition.
                                                             (line    6)
* MySQL Cluster, direct connections between nodes: mysql-cluster-tcp-definition-direct.
                                                             (line    6)
* MySQL Cluster, ENTER SINGLE USER MODE command: mysql-cluster-mgm-client-commands.
                                                             (line   91)
* MySQL Cluster, ERROR Events:           mysql-cluster-log-events.
                                                             (line  199)
* MySQL Cluster, error logs:             mysql-cluster-programs-ndbd.
                                                             (line  266)
* MySQL Cluster, error messages:         faqs-mysql-cluster. (line    6)
* MySQL Cluster, event log format:       mysql-cluster-log-events.
                                                             (line    6)
* MySQL Cluster, event logging thresholds: mysql-cluster-logging-management-commands.
                                                             (line   34)
* MySQL Cluster, event logs <1>:         mysql-cluster-logging-management-commands.
                                                             (line    6)
* MySQL Cluster, event logs:             mysql-cluster-event-reports.
                                                             (line   12)
* MySQL Cluster, event severity levels:  mysql-cluster-logging-management-commands.
                                                             (line   55)
* MySQL Cluster, event types <1>:        mysql-cluster-log-events.
                                                             (line   20)
* MySQL Cluster, event types:            mysql-cluster-event-reports.
                                                             (line   49)
* MySQL Cluster, EXIT command:           mysql-cluster-mgm-client-commands.
                                                             (line  114)
* MySQL Cluster, EXIT SINGLE USER MODE command: mysql-cluster-mgm-client-commands.
                                                             (line  104)
* MySQL Cluster, FAQ:                    faqs-mysql-cluster. (line    6)
* MySQL Cluster, general description:    mysql-cluster-overview.
                                                             (line   14)
* MySQL Cluster, hardware requirements:  faqs-mysql-cluster. (line    6)
* MySQL Cluster, HELP command:           mysql-cluster-mgm-client-commands.
                                                             (line   20)
* MySQL Cluster, HostName parameter, and security: mysql-cluster-security-networking-issues.
                                                             (line   40)
* MySQL Cluster, how to obtain:          faqs-mysql-cluster. (line    6)
* MySQL Cluster, importing existing tables: faqs-mysql-cluster.
                                                             (line    6)
* MySQL Cluster, INFO Events:            mysql-cluster-log-events.
                                                             (line  213)
* MySQL Cluster, information sources:    mysql-cluster.      (line   53)
* MySQL Cluster, insecurity of communication protocols: mysql-cluster-security-networking-issues.
                                                             (line   12)
* MySQL Cluster, installation:           mysql-cluster-installation.
                                                             (line   15)
* MySQL Cluster, installation (Linux):   mysql-cluster-install-linux.
                                                             (line   12)
* MySQL Cluster, installing binary release (Linux): mysql-cluster-install-linux-binary.
                                                             (line    6)
* MySQL Cluster, installing from source (Linux): mysql-cluster-install-linux-source.
                                                             (line    6)
* MySQL Cluster, installing RPM (Linux): mysql-cluster-install-linux-rpm.
                                                             (line    6)
* MySQL Cluster, interconnects:          mysql-cluster-interconnects.
                                                             (line   11)
* MySQL Cluster, log files:              mysql-cluster-programs-ndbd.
                                                             (line  257)
* MySQL Cluster, logging commands:       mysql-cluster-logging-management-commands.
                                                             (line    6)
* MySQL Cluster, management client (ndb_mgm): mysql-cluster-programs-ndb-mgm.
                                                             (line    6)
* MySQL Cluster, management commands:    mysql-cluster-log-statistics.
                                                             (line    6)
* MySQL Cluster, management node <1>:    mysql-cluster-mgm-definition.
                                                             (line    6)
* MySQL Cluster, management node:        mysql-cluster-basics.
                                                             (line    6)
* MySQL Cluster, management nodes:       mysql-cluster-programs-ndb-mgmd.
                                                             (line    6)
* MySQL Cluster, managing:               mysql-cluster-management.
                                                             (line   18)
* MySQL Cluster, master node:            faqs-mysql-cluster. (line    6)
* MySQL Cluster, MAX_ROWS:               create-table.       (line  629)
* MySQL Cluster, memory requirements:    faqs-mysql-cluster. (line    6)
* MySQL Cluster, memory usage and recovery <1>: mysql-cluster-rolling-restart.
                                                             (line   62)
* MySQL Cluster, memory usage and recovery: mysql-cluster-limitations-limits.
                                                             (line    9)
* MySQL Cluster, mgm:                    mysql-cluster-program-options-common.
                                                             (line    6)
* MySQL Cluster, mgm client:             mysql-cluster-mgm-client-commands.
                                                             (line    6)
* MySQL Cluster, mgm management client:  mysql-cluster-log-statistics.
                                                             (line    6)
* MySQL Cluster, mgm process:            mysql-cluster-programs-ndb-mgm.
                                                             (line   27)
* MySQL Cluster, mgmd:                   mysql-cluster-program-options-common.
                                                             (line    6)
* MySQL Cluster, mgmd process:           mysql-cluster-programs-ndb-mgmd.
                                                             (line   12)
* MySQL Cluster, mysqld process <1>:     mysql-cluster-programs-mysqld.
                                                             (line    6)
* MySQL Cluster, mysqld process:         mysql-cluster-program-options-mysqld.
                                                             (line    6)
* MySQL Cluster, ndb_mgm <1>:            mysql-cluster-programs-ndb-mgm.
                                                             (line    6)
* MySQL Cluster, ndb_mgm:                mysql-cluster-install-first-start.
                                                             (line   36)
* MySQL Cluster, ndb_mgmd process:       mysql-cluster-programs-ndb-mgmd.
                                                             (line    6)
* MySQL Cluster, ndb_size.pl (utility):  faqs-mysql-cluster. (line    6)
* MySQL Cluster, ndbd <1>:               mysql-cluster-program-options-common.
                                                             (line    6)
* MySQL Cluster, ndbd:                   mysql-cluster-programs-ndbd.
                                                             (line    6)
* MySQL Cluster, ndbd process <1>:       mysql-cluster-log-statistics.
                                                             (line  165)
* MySQL Cluster, ndbd process:           mysql-cluster-programs-ndbd.
                                                             (line   17)
* MySQL Cluster, network configuration, and security: mysql-cluster-security-networking-issues.
                                                             (line   59)
* MySQL Cluster, network transporters <1>: mysql-cluster-sci-sockets.
                                                             (line    6)
* MySQL Cluster, network transporters:   mysql-cluster-interconnects.
                                                             (line   11)
* MySQL Cluster, networking <1>:         mysql-cluster-sci-definition.
                                                             (line    6)
* MySQL Cluster, networking <2>:         mysql-cluster-shm-definition.
                                                             (line    6)
* MySQL Cluster, networking:             mysql-cluster-tcp-definition-direct.
                                                             (line    6)
* MySQL Cluster, networking requirements: faqs-mysql-cluster.
                                                             (line    6)
* MySQL Cluster, node failure (single user mode): mysql-cluster-single-user-mode.
                                                             (line   48)
* MySQL Cluster, node identifiers <1>:   mysql-cluster-sci-definition.
                                                             (line   26)
* MySQL Cluster, node identifiers:       mysql-cluster-shm-definition.
                                                             (line   27)
* MySQL Cluster, node logs:              mysql-cluster-event-reports.
                                                             (line   12)
* MySQL Cluster, node types:             faqs-mysql-cluster. (line    6)
* MySQL Cluster, NODERESTART Events:     mysql-cluster-log-events.
                                                             (line   92)
* MySQL Cluster, nodes and node groups:  mysql-cluster-nodes-groups.
                                                             (line    6)
* MySQL Cluster, nodes and types:        mysql-cluster-basics.
                                                             (line    6)
* MySQL Cluster, number of computers required: faqs-mysql-cluster.
                                                             (line    6)
* MySQL Cluster, partitions:             mysql-cluster-nodes-groups.
                                                             (line    6)
* MySQL Cluster, performance:            mysql-cluster-interconnects-performance.
                                                             (line    6)
* MySQL Cluster, performing queries:     mysql-cluster-install-example-data.
                                                             (line    6)
* MySQL Cluster, platforms supported:    faqs-mysql-cluster. (line    6)
* MySQL Cluster, process management:     mysql-cluster-programs.
                                                             (line   30)
* MySQL Cluster, QUIT command:           mysql-cluster-mgm-client-commands.
                                                             (line  114)
* MySQL Cluster, replicas:               mysql-cluster-nodes-groups.
                                                             (line    6)
* MySQL Cluster, requirements:           mysql-cluster-overview-requirements.
                                                             (line    6)
* MySQL Cluster, resetting:              mysql-cluster-rolling-restart.
                                                             (line   38)
* MySQL Cluster, RESTART command:        mysql-cluster-mgm-client-commands.
                                                             (line   68)
* MySQL Cluster, restarting:             mysql-cluster-install-shutdown-restart.
                                                             (line    6)
* MySQL Cluster, restoring backups:      mysql-cluster-programs-ndb-restore.
                                                             (line    6)
* MySQL Cluster, roles of computers:     faqs-mysql-cluster. (line    6)
* MySQL Cluster, runtime statistics:     mysql-cluster-log-statistics.
                                                             (line    6)
* MySQL Cluster, SCI (Scalable Coherent Interface) <1>: mysql-cluster-sci-sockets.
                                                             (line    6)
* MySQL Cluster, SCI (Scalable Coherent Interface): mysql-cluster-sci-definition.
                                                             (line    6)
* MySQL Cluster, security <1>:           faqs-mysql-cluster. (line    6)
* MySQL Cluster, security:               mysql-cluster-security.
                                                             (line   12)
* MySQL Cluster, security procedures:    mysql-cluster-security-mysql-security-procedures.
                                                             (line    6)
* MySQL Cluster, security, and firewalls: mysql-cluster-security-networking-issues.
                                                             (line   98)
* MySQL Cluster, security, and HostName parameter: mysql-cluster-security-networking-issues.
                                                             (line   40)
* MySQL Cluster, security, and network configuration: mysql-cluster-security-networking-issues.
                                                             (line   59)
* MySQL Cluster, security, and network ports: mysql-cluster-security-networking-issues.
                                                             (line  182)
* MySQL Cluster, security, and remote administration: mysql-cluster-security-networking-issues.
                                                             (line  189)
* MySQL Cluster, security, networking:   mysql-cluster-security-networking-issues.
                                                             (line    6)
* MySQL Cluster, shared memory transport: mysql-cluster-shm-definition.
                                                             (line    6)
* MySQL Cluster, SHOW command:           mysql-cluster-mgm-client-commands.
                                                             (line   24)
* MySQL Cluster, SHUTDOWN command:       mysql-cluster-mgm-client-commands.
                                                             (line  120)
* MySQL Cluster, shutting down:          mysql-cluster-install-shutdown-restart.
                                                             (line    6)
* MySQL Cluster, single user mode <1>:   mysql-cluster-single-user-mode.
                                                             (line    6)
* MySQL Cluster, single user mode:       mysql-cluster-mgm-client-commands.
                                                             (line   91)
* MySQL Cluster, SQL node <1>:           mysql-cluster-api-definition.
                                                             (line    6)
* MySQL Cluster, SQL node:               mysql-cluster-basics.
                                                             (line    6)
* MySQL Cluster, SQL nodes:              mysql-cluster-programs-mysqld.
                                                             (line    6)
* MySQL Cluster, SQL statements:         faqs-mysql-cluster. (line    6)
* MySQL Cluster, SQL statements for monitoring: mysql-cluster-sql-statements.
                                                             (line    6)
* MySQL Cluster, START command:          mysql-cluster-mgm-client-commands.
                                                             (line   34)
* MySQL Cluster, start phases (summary): mysql-cluster-start-phases.
                                                             (line    6)
* MySQL Cluster, starting:               mysql-cluster-quick.
                                                             (line    6)
* MySQL Cluster, starting and stopping:  faqs-mysql-cluster. (line    6)
* MySQL Cluster, starting nodes:         mysql-cluster-install-first-start.
                                                             (line    6)
* MySQL Cluster, starting or restarting: mysql-cluster-start-phases.
                                                             (line    6)
* MySQL Cluster, STARTUP Events:         mysql-cluster-log-events.
                                                             (line   56)
* MySQL Cluster, STATISTICS Events:      mysql-cluster-log-events.
                                                             (line  175)
* MySQL Cluster, STATUS command:         mysql-cluster-mgm-client-commands.
                                                             (line   86)
* MySQL Cluster, STOP command:           mysql-cluster-mgm-client-commands.
                                                             (line   53)
* MySQL Cluster, storage requirements:   storage-requirements.
                                                             (line   35)
* MySQL Cluster, Table is full errors:   faqs-mysql-cluster. (line    6)
* MySQL Cluster, thread states:          mysql-cluster-thread-states.
                                                             (line    6)
* MySQL Cluster, trace files:            mysql-cluster-programs-ndbd.
                                                             (line  298)
* MySQL Cluster, transaction handling:   mysql-cluster-limitations-transactions.
                                                             (line  106)
* MySQL Cluster, transactions:           mysql-cluster-ndbd-definition.
                                                             (line  377)
* MySQL Cluster, transporters, Scalable Coherent Interface (SCI): mysql-cluster-sci-definition.
                                                             (line    6)
* MySQL Cluster, transporters, shared memory (SHM): mysql-cluster-shm-definition.
                                                             (line    6)
* MySQL Cluster, transporters, TCP/IP:   mysql-cluster-tcp-definition-direct.
                                                             (line    6)
* MySQL Cluster, troubleshooting backups: mysql-cluster-backup-troubleshooting.
                                                             (line    6)
* MySQL Cluster, upgrades and downgrades <1>: mysql-cluster-rolling-restart.
                                                             (line    6)
* MySQL Cluster, upgrades and downgrades: mysql-cluster-upgrade-downgrade.
                                                             (line    6)
* MySQL Cluster, using tables and data:  mysql-cluster-install-example-data.
                                                             (line    6)
* MySQL Cluster, vs replication:         faqs-mysql-cluster. (line    6)
* mysql command options:                 mysql-command-options.
                                                             (line    6)
* mysql commands, list of:               mysql-commands.     (line   11)
* MySQL Community Server, release notes <1>: news-5-0-x.     (line  115)
* MySQL Community Server, release notes: news.               (line   17)
* MySQL Dolphin name:                    history.            (line    6)
* MySQL Enterprise, release notes <1>:   news-5-0-x.         (line  115)
* MySQL Enterprise, release notes:       news.               (line   17)
* MySQL history:                         history.            (line    6)
* mysql history file:                    mysql-history-file. (line    6)
* MySQL Instance Manager:                instance-manager.   (line   16)
* MySQL mailing lists:                   mailing-lists.      (line   10)
* MySQL name:                            history.            (line    6)
* MySQL privileges, and MySQL Cluster:   mysql-cluster-security-mysql-privileges.
                                                             (line   10)
* mysql prompt command:                  mysql-commands.     (line  297)
* MySQL server, mysqld <1>:              mysqld-server.      (line   18)
* MySQL server, mysqld:                  mysqld.             (line    6)
* mysql source (command for reading from text files) <1>: batch-commands.
                                                             (line    6)
* mysql source (command for reading from text files): batch-mode.
                                                             (line   90)
* MySQL source distribution:             which-version.      (line   19)
* MySQL storage engines:                 storage-engines.    (line   19)
* MySQL system tables, and MySQL Cluster: mysql-cluster-security-mysql-privileges.
                                                             (line   23)
* MySQL system tables, and replication:  replication-features-mysqldb.
                                                             (line    6)
* MySQL version:                         getting-mysql.      (line    6)
* mysql, auto-rehash option:             mysql-command-options.
                                                             (line  151)
* mysql, batch option:                   mysql-command-options.
                                                             (line  165)
* mysql, character-sets-dir option:      mysql-command-options.
                                                             (line  175)
* mysql, charset command:                mysql-commands.     (line   61)
* mysql, clear command:                  mysql-commands.     (line   70)
* mysql, column-names option:            mysql-command-options.
                                                             (line  180)
* mysql, comments option:                mysql-command-options.
                                                             (line  184)
* mysql, compress option:                mysql-command-options.
                                                             (line  191)
* mysql, connect command:                mysql-commands.     (line   75)
* mysql, database option:                mysql-command-options.
                                                             (line  196)
* mysql, debug option:                   mysql-command-options.
                                                             (line  200)
* mysql, debug-info option:              mysql-command-options.
                                                             (line  205)
* mysql, default-character-set option:   mysql-command-options.
                                                             (line  209)
* MySQL, defined:                        what-is-mysql.      (line    6)
* mysql, delimiter command:              mysql-commands.     (line   82)
* mysql, delimiter option:               mysql-command-options.
                                                             (line  223)
* mysql, disable named commands:         mysql-command-options.
                                                             (line  228)
* mysql, edit command:                   mysql-commands.     (line  117)
* mysql, ego command:                    mysql-commands.     (line  126)
* mysql, execute option:                 mysql-command-options.
                                                             (line  236)
* mysql, exit command:                   mysql-commands.     (line  135)
* mysql, force option:                   mysql-command-options.
                                                             (line  243)
* mysql, go command:                     mysql-commands.     (line  139)
* mysql, help command:                   mysql-commands.     (line   51)
* mysql, help option:                    mysql-command-options.
                                                             (line  147)
* mysql, host option:                    mysql-command-options.
                                                             (line  247)
* mysql, html option:                    mysql-command-options.
                                                             (line  251)
* mysql, i-am-a-dummy option:            mysql-command-options.
                                                             (line  435)
* mysql, ignore-spaces option:           mysql-command-options.
                                                             (line  255)
* MySQL, introduction:                   what-is-mysql.      (line    6)
* mysql, line-numbers option:            mysql-command-options.
                                                             (line  261)
* mysql, local-infile option:            mysql-command-options.
                                                             (line  266)
* mysql, named-commands option:          mysql-command-options.
                                                             (line  274)
* mysql, no-auto-rehash option:          mysql-command-options.
                                                             (line  281)
* mysql, no-beep option:                 mysql-command-options.
                                                             (line  286)
* mysql, no-named-commands option:       mysql-command-options.
                                                             (line  290)
* mysql, no-pager option:                mysql-command-options.
                                                             (line  295)
* mysql, no-tee option:                  mysql-command-options.
                                                             (line  300)
* mysql, nopager command:                mysql-commands.     (line  143)
* mysql, notee command:                  mysql-commands.     (line  149)
* mysql, nowarning command:              mysql-commands.     (line  154)
* mysql, one-database option:            mysql-command-options.
                                                             (line  305)
* mysql, pager command:                  mysql-commands.     (line  159)
* mysql, pager option:                   mysql-command-options.
                                                             (line  348)
* mysql, password option:                mysql-command-options.
                                                             (line  357)
* mysql, pipe option:                    mysql-command-options.
                                                             (line  369)
* mysql, port option:                    mysql-command-options.
                                                             (line  374)
* mysql, print command:                  mysql-commands.     (line  181)
* mysql, prompt command:                 mysql-commands.     (line  185)
* mysql, prompt option:                  mysql-command-options.
                                                             (line  378)
* MySQL, pronunciation:                  what-is-mysql.      (line   84)
* mysql, protocol option:                mysql-command-options.
                                                             (line  384)
* mysql, quick option:                   mysql-command-options.
                                                             (line  391)
* mysql, quit command:                   mysql-commands.     (line  194)
* mysql, raw option:                     mysql-command-options.
                                                             (line  397)
* mysql, reconnect option:               mysql-command-options.
                                                             (line  428)
* mysql, rehash command:                 mysql-commands.     (line  198)
* mysql, safe-updates option:            mysql-command-options.
                                                             (line  435)
* mysql, secure-auth option:             mysql-command-options.
                                                             (line  443)
* mysql, show-warnings option:           mysql-command-options.
                                                             (line  449)
* mysql, sigint-ignore option:           mysql-command-options.
                                                             (line  455)
* mysql, silent option:                  mysql-command-options.
                                                             (line  459)
* mysql, skip-column-names option:       mysql-command-options.
                                                             (line  468)
* mysql, skip-line-numbers option:       mysql-command-options.
                                                             (line  472)
* mysql, socket option:                  mysql-command-options.
                                                             (line  477)
* mysql, source command:                 mysql-commands.     (line  204)
* mysql, SSL options:                    mysql-command-options.
                                                             (line  482)
* mysql, status command:                 mysql-commands.     (line  209)
* mysql, system command:                 mysql-commands.     (line  216)
* mysql, table option:                   mysql-command-options.
                                                             (line  488)
* mysql, tee command:                    mysql-commands.     (line  222)
* mysql, tee option:                     mysql-command-options.
                                                             (line  494)
* mysql, unbuffered option:              mysql-command-options.
                                                             (line  500)
* MySQL, upgrading:                      mysql-upgrade.      (line    6)
* mysql, use command:                    mysql-commands.     (line  236)
* mysql, user option:                    mysql-command-options.
                                                             (line  504)
* mysql, verbose option:                 mysql-command-options.
                                                             (line  508)
* mysql, version option:                 mysql-command-options.
                                                             (line  515)
* mysql, vertical option:                mysql-command-options.
                                                             (line  519)
* mysql, wait option:                    mysql-command-options.
                                                             (line  525)
* mysql, warnings command:               mysql-commands.     (line  240)
* mysql, xml option:                     mysql-command-options.
                                                             (line  530)
* mysql.server <1>:                      mysql-server.       (line    6)
* mysql.server:                          programs-overview.  (line   50)
* mysql.server, basedir option:          mysql-server.       (line   36)
* mysql.server, datadir option:          mysql-server.       (line   40)
* mysql.server, pid-file option:         mysql-server.       (line   44)
* mysql.server, service-startup-timeout option: mysql-server.
                                                             (line   49)
* mysql.server, use-manager option:      mysql-server.       (line   63)
* mysql.server, use-mysqld_safe option:  mysql-server.       (line   58)
* mysql.server, user option:             mysql-server.       (line   68)
* mysql.sock, changing location of:      source-configuration-options.
                                                             (line  330)
* mysql.sock, protection:                problems-with-mysql-sock.
                                                             (line    6)
* MYSQL323 SQL mode:                     server-sql-mode.    (line  422)
* MYSQL40 SQL mode:                      server-sql-mode.    (line  426)
* mysql_affected_rows():                 mysql-affected-rows.
                                                             (line    6)
* mysql_autocommit():                    mysql-autocommit.   (line    6)
* MYSQL_BIND C type:                     c-api-prepared-statement-data-structures.
                                                             (line   51)
* mysql_change_user():                   mysql-change-user.  (line    6)
* mysql_character_set_name():            mysql-character-set-name.
                                                             (line    6)
* mysql_close():                         mysql-close.        (line    6)
* mysql_commit():                        mysql-commit.       (line    6)
* mysql_config:                          mysql-config.       (line    6)
* mysql_config, cflags option:           mysql-config.       (line   11)
* mysql_config, embedded option:         mysql-config.       (line   24)
* mysql_config, include option:          mysql-config.       (line   20)
* mysql_config, libmysqld-libs option:   mysql-config.       (line   24)
* mysql_config, libs option:             mysql-config.       (line   29)
* mysql_config, libs_r option:           mysql-config.       (line   34)
* mysql_config, port option:             mysql-config.       (line   39)
* mysql_config, socket option:           mysql-config.       (line   43)
* mysql_config, version option:          mysql-config.       (line   47)
* mysql_connect():                       mysql-connect.      (line    6)
* mysql_convert_table_format <1>:        mysql-convert-table-format.
                                                             (line    6)
* mysql_convert_table_format:            programs-overview.  (line  223)
* mysql_convert_table_format, force option: mysql-convert-table-format.
                                                             (line   28)
* mysql_convert_table_format, help option: mysql-convert-table-format.
                                                             (line   24)
* mysql_convert_table_format, host option: mysql-convert-table-format.
                                                             (line   32)
* mysql_convert_table_format, password option: mysql-convert-table-format.
                                                             (line   36)
* mysql_convert_table_format, port option: mysql-convert-table-format.
                                                             (line   46)
* mysql_convert_table_format, socket option: mysql-convert-table-format.
                                                             (line   50)
* mysql_convert_table_format, type option: mysql-convert-table-format.
                                                             (line   54)
* mysql_convert_table_format, user option: mysql-convert-table-format.
                                                             (line   59)
* mysql_convert_table_format, verbose option: mysql-convert-table-format.
                                                             (line   63)
* mysql_convert_table_format, version option: mysql-convert-table-format.
                                                             (line   67)
* mysql_create_db():                     mysql-create-db.    (line    6)
* mysql_data_seek():                     mysql-data-seek.    (line    6)
* MYSQL_DEBUG environment variable <1>:  debugging-client.   (line   10)
* MYSQL_DEBUG environment variable <2>:  programs-overview.  (line  329)
* MYSQL_DEBUG environment variable:      environment-variables.
                                                             (line   18)
* mysql_debug():                         mysql-debug.        (line    6)
* mysql_drop_db():                       mysql-drop-db.      (line    6)
* mysql_dump_debug_info():               mysql-dump-debug-info.
                                                             (line    6)
* mysql_eof():                           mysql-eof.          (line    6)
* mysql_errno():                         mysql-errno.        (line    6)
* mysql_error():                         mysql-error.        (line    6)
* mysql_escape_string():                 mysql-escape-string.
                                                             (line    6)
* mysql_explain_log <1>:                 mysql-explain-log.  (line    6)
* mysql_explain_log:                     programs-overview.  (line  228)
* mysql_explain_log, date option:        mysql-explain-log.  (line   29)
* mysql_explain_log, help option:        mysql-explain-log.  (line   25)
* mysql_explain_log, host option:        mysql-explain-log.  (line   33)
* mysql_explain_log, password option:    mysql-explain-log.  (line   37)
* mysql_explain_log, printerror option:  mysql-explain-log.  (line   44)
* mysql_explain_log, socket option:      mysql-explain-log.  (line   48)
* mysql_explain_log, user option:        mysql-explain-log.  (line   53)
* mysql_fetch_field():                   mysql-fetch-field.  (line    6)
* mysql_fetch_field_direct():            mysql-fetch-field-direct.
                                                             (line    6)
* mysql_fetch_fields():                  mysql-fetch-fields. (line    6)
* mysql_fetch_lengths():                 mysql-fetch-lengths.
                                                             (line    6)
* mysql_fetch_row():                     mysql-fetch-row.    (line    6)
* MYSQL_FIELD C type:                    c-api-data-structures.
                                                             (line   34)
* mysql_field_count() <1>:               mysql-num-fields.   (line    6)
* mysql_field_count():                   mysql-field-count.  (line    6)
* MYSQL_FIELD_OFFSET C type:             c-api-data-structures.
                                                             (line   44)
* mysql_field_seek():                    mysql-field-seek.   (line    6)
* mysql_field_tell():                    mysql-field-tell.   (line    6)
* mysql_find_rows <1>:                   mysql-find-rows.    (line    6)
* mysql_find_rows:                       programs-overview.  (line  233)
* mysql_find_rows, help option:          mysql-find-rows.    (line   31)
* mysql_find_rows, regexp option:        mysql-find-rows.    (line   35)
* mysql_find_rows, rows option:          mysql-find-rows.    (line   39)
* mysql_find_rows, skip-use-db option:   mysql-find-rows.    (line   43)
* mysql_find_rows, start_row option:     mysql-find-rows.    (line   47)
* mysql_fix_extensions <1>:              mysql-fix-extensions.
                                                             (line    6)
* mysql_fix_extensions:                  programs-overview.  (line  239)
* mysql_fix_privilege_tables <1>:        mysql-fix-privilege-tables.
                                                             (line    6)
* mysql_fix_privilege_tables:            programs-overview.  (line   87)
* mysql_free_result():                   mysql-free-result.  (line    6)
* mysql_get_character_set_info():        mysql-get-character-set-info.
                                                             (line    6)
* mysql_get_client_info():               mysql-get-client-info.
                                                             (line    6)
* mysql_get_client_version():            mysql-get-client-version.
                                                             (line    6)
* mysql_get_host_info():                 mysql-get-host-info.
                                                             (line    6)
* mysql_get_proto_info():                mysql-get-proto-info.
                                                             (line    6)
* mysql_get_server_info():               mysql-get-server-info.
                                                             (line    6)
* mysql_get_server_version():            mysql-get-server-version.
                                                             (line    6)
* mysql_get_ssl_cipher():                mysql-get-ssl-cipher.
                                                             (line    6)
* MYSQL_GROUP_SUFFIX environment variable: environment-variables.
                                                             (line   18)
* mysql_hex_string():                    mysql-hex-string.   (line    6)
* MYSQL_HISTFILE environment variable <1>: mysql-history-file.
                                                             (line    6)
* MYSQL_HISTFILE environment variable:   environment-variables.
                                                             (line   18)
* MYSQL_HOME environment variable:       environment-variables.
                                                             (line   18)
* MYSQL_HOST environment variable <1>:   connecting.         (line  231)
* MYSQL_HOST environment variable:       environment-variables.
                                                             (line   18)
* mysql_info() <1>:                      mysql-info.         (line    6)
* mysql_info() <2>:                      update.             (line   86)
* mysql_info() <3>:                      load-data.          (line  673)
* mysql_info() <4>:                      insert.             (line  202)
* mysql_info():                          alter-table.        (line  447)
* mysql_init():                          mysql-init.         (line    6)
* mysql_insert_id() <1>:                 mysql-insert-id.    (line    6)
* mysql_insert_id() <2>:                 insert.             (line  206)
* mysql_insert_id():                     ansi-diff-transactions.
                                                             (line  160)
* mysql_install_db <1>:                  mysql-install-db.   (line    6)
* mysql_install_db <2>:                  programs-overview.  (line   96)
* mysql_install_db:                      mysql-install-db-problems.
                                                             (line    6)
* mysql_install_db, basedir option:      mysql-install-db.   (line   45)
* mysql_install_db, datadir option:      mysql-install-db.   (line   55)
* mysql_install_db, force option:        mysql-install-db.   (line   49)
* mysql_install_db, ldata option:        mysql-install-db.   (line   55)
* mysql_install_db, rpm option:          mysql-install-db.   (line   59)
* mysql_install_db, skip-name-resolve option: mysql-install-db.
                                                             (line   64)
* mysql_install_db, srcdir option:       mysql-install-db.   (line   69)
* mysql_install_db, user option:         mysql-install-db.   (line   76)
* mysql_install_db, verbose option:      mysql-install-db.   (line   85)
* mysql_install_db, windows option:      mysql-install-db.   (line   89)
* mysql_kill():                          mysql-kill.         (line    6)
* mysql_library_end():                   mysql-library-end.  (line    6)
* mysql_library_init():                  mysql-library-init. (line    6)
* mysql_list_dbs():                      mysql-list-dbs.     (line    6)
* mysql_list_fields():                   mysql-list-fields.  (line    6)
* mysql_list_processes():                mysql-list-processes.
                                                             (line    6)
* mysql_list_tables():                   mysql-list-tables.  (line    6)
* mysql_more_results():                  mysql-more-results. (line    6)
* mysql_next_result():                   mysql-next-result.  (line    6)
* mysql_num_fields():                    mysql-num-fields.   (line    6)
* mysql_num_rows():                      mysql-num-rows.     (line    6)
* mysql_options():                       mysql-options.      (line    6)
* mysql_ping():                          mysql-ping.         (line    6)
* MYSQL_PS1 environment variable:        environment-variables.
                                                             (line   18)
* MYSQL_PWD environment variable <1>:    connecting.         (line  231)
* MYSQL_PWD environment variable <2>:    programs-overview.  (line  329)
* MYSQL_PWD environment variable:        environment-variables.
                                                             (line   18)
* mysql_query() <1>:                     c-api-problems.     (line   12)
* mysql_query():                         mysql-query.        (line    6)
* mysql_real_connect():                  mysql-real-connect. (line    6)
* mysql_real_escape_string() <1>:        mysql-real-escape-string.
                                                             (line    6)
* mysql_real_escape_string() <2>:        string-functions.   (line  537)
* mysql_real_escape_string():            string-literals.    (line  141)
* mysql_real_query():                    mysql-real-query.   (line    6)
* mysql_refresh():                       mysql-refresh.      (line    6)
* mysql_reload():                        mysql-reload.       (line    6)
* MYSQL_RES C type:                      c-api-data-structures.
                                                             (line   17)
* mysql_rollback():                      mysql-rollback.     (line    6)
* MYSQL_ROW C type:                      c-api-data-structures.
                                                             (line   25)
* mysql_row_seek():                      mysql-row-seek.     (line    6)
* mysql_row_tell():                      mysql-row-tell.     (line    6)
* mysql_secure_installation <1>:         mysql-secure-installation.
                                                             (line    6)
* mysql_secure_installation:             programs-overview.  (line  104)
* mysql_select_db():                     mysql-select-db.    (line    6)
* mysql_server_end():                    mysql-server-end.   (line    6)
* mysql_server_init():                   mysql-server-init.  (line    6)
* mysql_set_character_set():             mysql-set-character-set.
                                                             (line    6)
* mysql_set_local_infile_default():      mysql-set-local-infile-default.
                                                             (line    6)
* mysql_set_server_option():             mysql-set-server-option.
                                                             (line    6)
* mysql_setpermission <1>:               mysql-setpermission.
                                                             (line    6)
* mysql_setpermission:                   programs-overview.  (line  246)
* mysql_setpermission, help option:      mysql-setpermission.
                                                             (line   29)
* mysql_setpermission, host option:      mysql-setpermission.
                                                             (line   33)
* mysql_setpermission, password option:  mysql-setpermission.
                                                             (line   37)
* mysql_setpermission, port option:      mysql-setpermission.
                                                             (line   47)
* mysql_setpermission, socket option:    mysql-setpermission.
                                                             (line   51)
* mysql_setpermission, user option:      mysql-setpermission.
                                                             (line   55)
* mysql_shutdown():                      mysql-shutdown.     (line    6)
* mysql_sqlstate():                      mysql-sqlstate.     (line    6)
* mysql_ssl_set():                       mysql-ssl-set.      (line    6)
* mysql_stat():                          mysql-stat.         (line    6)
* MYSQL_STMT C type:                     c-api-prepared-statement-data-structures.
                                                             (line   34)
* mysql_stmt_affected_rows():            mysql-stmt-affected-rows.
                                                             (line    6)
* mysql_stmt_attr_get():                 mysql-stmt-attr-get.
                                                             (line    6)
* mysql_stmt_attr_set():                 mysql-stmt-attr-set.
                                                             (line    6)
* mysql_stmt_bind_param():               mysql-stmt-bind-param.
                                                             (line    6)
* mysql_stmt_bind_result():              mysql-stmt-bind-result.
                                                             (line    6)
* mysql_stmt_close():                    mysql-stmt-close.   (line    6)
* mysql_stmt_data_seek():                mysql-stmt-data-seek.
                                                             (line    6)
* mysql_stmt_errno():                    mysql-stmt-errno.   (line    6)
* mysql_stmt_error():                    mysql-stmt-error.   (line    6)
* mysql_stmt_execute():                  mysql-stmt-execute. (line    6)
* mysql_stmt_fetch():                    mysql-stmt-fetch.   (line    6)
* mysql_stmt_fetch_column():             mysql-stmt-fetch-column.
                                                             (line    6)
* mysql_stmt_field_count():              mysql-stmt-field-count.
                                                             (line    6)
* mysql_stmt_free_result():              mysql-stmt-free-result.
                                                             (line    6)
* mysql_stmt_init():                     mysql-stmt-init.    (line    6)
* mysql_stmt_insert_id():                mysql-stmt-insert-id.
                                                             (line    6)
* mysql_stmt_num_rows():                 mysql-stmt-num-rows.
                                                             (line    6)
* mysql_stmt_param_count():              mysql-stmt-param-count.
                                                             (line    6)
* mysql_stmt_param_metadata():           mysql-stmt-param-metadata.
                                                             (line    6)
* mysql_stmt_prepare():                  mysql-stmt-prepare. (line    6)
* mysql_stmt_reset():                    mysql-stmt-reset.   (line    6)
* mysql_stmt_result_metadata:            mysql-stmt-result-metadata.
                                                             (line    6)
* mysql_stmt_row_seek():                 mysql-stmt-row-seek.
                                                             (line    6)
* mysql_stmt_row_tell():                 mysql-stmt-row-tell.
                                                             (line    6)
* mysql_stmt_send_long_data():           mysql-stmt-send-long-data.
                                                             (line    6)
* mysql_stmt_sqlstate():                 mysql-stmt-sqlstate.
                                                             (line    6)
* mysql_stmt_store_result():             mysql-stmt-store-result.
                                                             (line    6)
* mysql_store_result() <1>:              c-api-problems.     (line   12)
* mysql_store_result():                  mysql-store-result. (line    6)
* mysql_tableinfo <1>:                   mysql-tableinfo.    (line    6)
* mysql_tableinfo:                       programs-overview.  (line  251)
* mysql_tableinfo, clear option:         mysql-tableinfo.    (line   82)
* mysql_tableinfo, clear-only option:    mysql-tableinfo.    (line   86)
* mysql_tableinfo, col option:           mysql-tableinfo.    (line   91)
* mysql_tableinfo, help option:          mysql-tableinfo.    (line   78)
* mysql_tableinfo, host option:          mysql-tableinfo.    (line   95)
* mysql_tableinfo, idx option:           mysql-tableinfo.    (line   99)
* mysql_tableinfo, password option:      mysql-tableinfo.    (line  103)
* mysql_tableinfo, port option:          mysql-tableinfo.    (line  113)
* mysql_tableinfo, prefix option:        mysql-tableinfo.    (line  117)
* mysql_tableinfo, quiet option:         mysql-tableinfo.    (line  121)
* mysql_tableinfo, socket option:        mysql-tableinfo.    (line  125)
* mysql_tableinfo, tbl-status option:    mysql-tableinfo.    (line  129)
* mysql_tableinfo, user option:          mysql-tableinfo.    (line  135)
* MYSQL_TCP_PORT environment variable <1>: multiple-server-clients.
                                                             (line   27)
* MYSQL_TCP_PORT environment variable <2>: multiple-unix-servers.
                                                             (line   68)
* MYSQL_TCP_PORT environment variable <3>: programs-overview.
                                                             (line  329)
* MYSQL_TCP_PORT environment variable:   environment-variables.
                                                             (line   18)
* mysql_thread_end():                    mysql-thread-end.   (line    6)
* mysql_thread_id():                     mysql-thread-id.    (line    6)
* mysql_thread_init():                   mysql-thread-init.  (line    6)
* mysql_thread_safe():                   mysql-thread-safe.  (line    6)
* MYSQL_TIME C type:                     c-api-prepared-statement-data-structures.
                                                             (line  246)
* mysql_tzinfo_to_sql <1>:               mysql-tzinfo-to-sql.
                                                             (line    6)
* mysql_tzinfo_to_sql:                   programs-overview.  (line  109)
* MYSQL_UNIX_PORT environment variable <1>: multiple-server-clients.
                                                             (line   27)
* MYSQL_UNIX_PORT environment variable <2>: multiple-unix-servers.
                                                             (line   68)
* MYSQL_UNIX_PORT environment variable <3>: programs-overview.
                                                             (line  329)
* MYSQL_UNIX_PORT environment variable <4>: environment-variables.
                                                             (line   18)
* MYSQL_UNIX_PORT environment variable:  mysql-install-db-problems.
                                                             (line   83)
* mysql_upgrade <1>:                     access-denied.      (line   83)
* mysql_upgrade <2>:                     mysql-upgrade.      (line    6)
* mysql_upgrade:                         programs-overview.  (line  116)
* mysql_upgrade, basedir option:         mysql-upgrade.      (line  103)
* mysql_upgrade, datadir option:         mysql-upgrade.      (line  108)
* mysql_upgrade, force option:           mysql-upgrade.      (line  113)
* mysql_upgrade, help option:            mysql-upgrade.      (line   99)
* mysql_upgrade, mysql_upgrade_info file: mysql-upgrade.     (line   70)
* mysql_upgrade, tmpdir option:          mysql-upgrade.      (line  120)
* mysql_upgrade, user option:            mysql-upgrade.      (line  125)
* mysql_upgrade, verbose option:         mysql-upgrade.      (line  130)
* mysql_upgrade_info file, mysql_upgrade: mysql-upgrade.     (line   70)
* mysql_use_result():                    mysql-use-result.   (line    6)
* mysql_waitpid <1>:                     mysql-waitpid.      (line    6)
* mysql_waitpid:                         programs-overview.  (line  256)
* mysql_waitpid, help option:            mysql-waitpid.      (line   27)
* mysql_waitpid, verbose option:         mysql-waitpid.      (line   31)
* mysql_waitpid, version option:         mysql-waitpid.      (line   36)
* mysql_warning_count():                 mysql-warning-count.
                                                             (line    6)
* mysql_zap <1>:                         mysql-zap.          (line    6)
* mysql_zap:                             programs-overview.  (line  261)
* mysqlaccess <1>:                       mysqlaccess.        (line    6)
* mysqlaccess:                           programs-overview.  (line  192)
* mysqlaccess, brief option:             mysqlaccess.        (line   71)
* mysqlaccess, commit option:            mysqlaccess.        (line   75)
* mysqlaccess, copy option:              mysqlaccess.        (line   82)
* mysqlaccess, db option:                mysqlaccess.        (line   86)
* mysqlaccess, debug option:             mysqlaccess.        (line   90)
* mysqlaccess, help option:              mysqlaccess.        (line   67)
* mysqlaccess, host option:              mysqlaccess.        (line   94)
* mysqlaccess, howto option:             mysqlaccess.        (line   98)
* mysqlaccess, old_server option:        mysqlaccess.        (line  103)
* mysqlaccess, password option:          mysqlaccess.        (line  108)
* mysqlaccess, plan option:              mysqlaccess.        (line  117)
* mysqlaccess, preview option:           mysqlaccess.        (line  121)
* mysqlaccess, relnotes option:          mysqlaccess.        (line  126)
* mysqlaccess, rhost option:             mysqlaccess.        (line  130)
* mysqlaccess, rollback option:          mysqlaccess.        (line  134)
* mysqlaccess, spassword option:         mysqlaccess.        (line  138)
* mysqlaccess, superuser option:         mysqlaccess.        (line  148)
* mysqlaccess, table option:             mysqlaccess.        (line  152)
* mysqlaccess, user option:              mysqlaccess.        (line  156)
* mysqlaccess, version option:           mysqlaccess.        (line  160)
* mysqladmin <1>:                        kill.               (line    6)
* mysqladmin <2>:                        flush.              (line    6)
* mysqladmin <3>:                        show-variables.     (line    9)
* mysqladmin <4>:                        show-status.        (line    9)
* mysqladmin <5>:                        drop-database.      (line   56)
* mysqladmin <6>:                        create-database.    (line   39)
* mysqladmin <7>:                        mysqladmin.         (line    6)
* mysqladmin:                            programs-overview.  (line  137)
* mysqladmin command options:            mysqladmin.         (line  209)
* mysqladmin option, mysqld_multi:       mysqld-multi.       (line  123)
* mysqladmin, character-sets-dir option: mysqladmin.         (line  290)
* mysqladmin, compress option:           mysqladmin.         (line  295)
* mysqladmin, count option:              mysqladmin.         (line  300)
* mysqladmin, debug option:              mysqladmin.         (line  305)
* mysqladmin, default-character-set option: mysqladmin.      (line  311)
* mysqladmin, force option:              mysqladmin.         (line  316)
* mysqladmin, help option:               mysqladmin.         (line  286)
* mysqladmin, host option:               mysqladmin.         (line  321)
* mysqladmin, password option:           mysqladmin.         (line  325)
* mysqladmin, pipe option:               mysqladmin.         (line  337)
* mysqladmin, port option:               mysqladmin.         (line  342)
* mysqladmin, protocol option:           mysqladmin.         (line  346)
* mysqladmin, relative option:           mysqladmin.         (line  353)
* mysqladmin, silent option:             mysqladmin.         (line  359)
* mysqladmin, sleep option:              mysqladmin.         (line  363)
* mysqladmin, socket option:             mysqladmin.         (line  370)
* mysqladmin, SSL options:               mysqladmin.         (line  375)
* mysqladmin, user option:               mysqladmin.         (line  381)
* mysqladmin, verbose option:            mysqladmin.         (line  385)
* mysqladmin, version option:            mysqladmin.         (line  389)
* mysqladmin, vertical option:           mysqladmin.         (line  393)
* mysqladmin, wait option:               mysqladmin.         (line  398)
* mysqlbinlog <1>:                       mysqlbinlog.        (line    6)
* mysqlbinlog:                           programs-overview.  (line  197)
* mysqlbinlog, character-sets-dir option: mysqlbinlog.       (line  146)
* mysqlbinlog, database option:          mysqlbinlog.        (line  151)
* mysqlbinlog, debug option:             mysqlbinlog.        (line  205)
* mysqlbinlog, disable-log-bin option:   mysqlbinlog.        (line  211)
* mysqlbinlog, force-read option:        mysqlbinlog.        (line  225)
* mysqlbinlog, help option:              mysqlbinlog.        (line  142)
* mysqlbinlog, hexdump option:           mysqlbinlog.        (line  232)
* mysqlbinlog, host option:              mysqlbinlog.        (line  238)
* mysqlbinlog, local-load option:        mysqlbinlog.        (line  242)
* mysqlbinlog, offset option:            mysqlbinlog.        (line  252)
* mysqlbinlog, password option:          mysqlbinlog.        (line  256)
* mysqlbinlog, port option:              mysqlbinlog.        (line  268)
* mysqlbinlog, position option:          mysqlbinlog.        (line  272)
* mysqlbinlog, protocol option:          mysqlbinlog.        (line  277)
* mysqlbinlog, read-from-remote-server option: mysqlbinlog.  (line  284)
* mysqlbinlog, result-file option:       mysqlbinlog.        (line  295)
* mysqlbinlog, set-charset option:       mysqlbinlog.        (line  299)
* mysqlbinlog, short-form option:        mysqlbinlog.        (line  305)
* mysqlbinlog, socket option:            mysqlbinlog.        (line  311)
* mysqlbinlog, start-datetime option:    mysqlbinlog.        (line  316)
* mysqlbinlog, start-position option:    mysqlbinlog.        (line  330)
* mysqlbinlog, stop-datetime option:     mysqlbinlog.        (line  339)
* mysqlbinlog, stop-position option:     mysqlbinlog.        (line  349)
* mysqlbinlog, to-last-log option:       mysqlbinlog.        (line  358)
* mysqlbinlog, user option:              mysqlbinlog.        (line  366)
* mysqlbinlog, version option:           mysqlbinlog.        (line  370)
* mysqlbug:                              mysqlbug.           (line    6)
* mysqlcheck <1>:                        mysqlcheck.         (line    6)
* mysqlcheck:                            programs-overview.  (line  145)
* mysqlcheck, all-databases option:      mysqlcheck.         (line  181)
* mysqlcheck, all-in-1 option:           mysqlcheck.         (line  187)
* mysqlcheck, analyze option:            mysqlcheck.         (line  193)
* mysqlcheck, auto-repair option:        mysqlcheck.         (line  197)
* mysqlcheck, character-sets-dir option: mysqlcheck.         (line  202)
* mysqlcheck, check option:              mysqlcheck.         (line  207)
* mysqlcheck, check-only-changed option: mysqlcheck.         (line  211)
* mysqlcheck, check-upgrade option:      mysqlcheck.         (line  216)
* mysqlcheck, compress option:           mysqlcheck.         (line  222)
* mysqlcheck, databases option:          mysqlcheck.         (line  227)
* mysqlcheck, debug option:              mysqlcheck.         (line  235)
* mysqlcheck, default-character-set option: mysqlcheck.      (line  240)
* mysqlcheck, extended option:           mysqlcheck.         (line  245)
* mysqlcheck, fast option:               mysqlcheck.         (line  254)
* mysqlcheck, force option:              mysqlcheck.         (line  258)
* mysqlcheck, help option:               mysqlcheck.         (line  177)
* mysqlcheck, host option:               mysqlcheck.         (line  262)
* mysqlcheck, medium-check option:       mysqlcheck.         (line  266)
* mysqlcheck, optimize option:           mysqlcheck.         (line  272)
* mysqlcheck, password option:           mysqlcheck.         (line  276)
* mysqlcheck, pipe option:               mysqlcheck.         (line  288)
* mysqlcheck, port option:               mysqlcheck.         (line  293)
* mysqlcheck, protocol option:           mysqlcheck.         (line  297)
* mysqlcheck, quick option:              mysqlcheck.         (line  304)
* mysqlcheck, repair option:             mysqlcheck.         (line  313)
* mysqlcheck, silent option:             mysqlcheck.         (line  318)
* mysqlcheck, socket option:             mysqlcheck.         (line  322)
* mysqlcheck, SSL options:               mysqlcheck.         (line  327)
* mysqlcheck, tables option:             mysqlcheck.         (line  333)
* mysqlcheck, use-frm option:            mysqlcheck.         (line  338)
* mysqlcheck, user option:               mysqlcheck.         (line  344)
* mysqlcheck, verbose option:            mysqlcheck.         (line  348)
* mysqlcheck, version option:            mysqlcheck.         (line  353)
* mysqlclient library:                   connectors-apis.    (line   23)
* mysqld:                                programs-overview.  (line   38)
* mysqld (MySQL Cluster):                mysql-cluster-programs.
                                                             (line   30)
* mysqld library:                        connectors-apis.    (line   23)
* mysqld option, mysqld_multi:           mysqld-multi.       (line  128)
* mysqld option, mysqld_safe:            mysqld-safe.        (line  181)
* mysqld options:                        server-parameters.  (line   11)
* mysqld server, buffer sizes:           server-parameters.  (line    6)
* mysqld, abort-slave-event-count option: replication-options-slave.
                                                             (line  122)
* mysqld, allow-suspicious-udfs option <1>: privileges-options.
                                                             (line   41)
* mysqld, allow-suspicious-udfs option:  server-options.     (line   81)
* mysqld, ansi option:                   server-options.     (line  102)
* mysqld, as MySQL Cluster process <1>:  mysql-cluster-programs-mysqld.
                                                             (line    6)
* mysqld, as MySQL Cluster process:      mysql-cluster-program-options-mysqld.
                                                             (line    6)
* mysqld, basedir option:                server-options.     (line  114)
* mysqld, bdb-home option:               bdb-start.          (line   39)
* mysqld, bdb-lock-detect option:        bdb-start.          (line   44)
* mysqld, bdb-logdir option:             bdb-start.          (line   49)
* mysqld, bdb-no-recover option:         bdb-start.          (line   53)
* mysqld, bdb-no-sync option:            bdb-start.          (line   57)
* mysqld, bdb-shared-data option:        bdb-start.          (line   63)
* mysqld, bdb-tmpdir option:             bdb-start.          (line   68)
* mysqld, big-tables option:             server-options.     (line  135)
* mysqld, bind-address option:           server-options.     (line  158)
* mysqld, binlog-do-db option:           replication-options-binary-log.
                                                             (line  133)
* mysqld, binlog-ignore-db option:       replication-options-binary-log.
                                                             (line  197)
* mysqld, bootstrap option:              server-options.     (line  183)
* mysqld, character-set-client-handshake option: server-options.
                                                             (line  218)
* mysqld, character-set-filesystem option: server-options.   (line  235)
* mysqld, character-set-server option:   server-options.     (line  257)
* mysqld, character-sets-dir option:     server-options.     (line  198)
* mysqld, chroot option:                 server-options.     (line  279)
* mysqld, collation-server option:       server-options.     (line  299)
* mysqld, command options:               server-options.     (line    6)
* mysqld, console option:                server-options.     (line  319)
* mysqld, core-file option:              server-options.     (line  331)
* mysqld, datadir option:                server-options.     (line  360)
* mysqld, debug option:                  server-options.     (line  380)
* mysqld, default-character-set option:  server-options.     (line  409)
* mysqld, default-collation option:      server-options.     (line  429)
* mysqld, default-storage-engine option: server-options.     (line  446)
* mysqld, default-table-type option:     server-options.     (line  460)
* mysqld, default-time-zone option:      server-options.     (line  477)
* mysqld, delay-key-write option <1>:    myisam-start.       (line   42)
* mysqld, delay-key-write option:        server-options.     (line  493)
* mysqld, des-key-file option:           server-options.     (line  527)
* mysqld, disconnect-slave-event-count option: replication-options-slave.
                                                             (line  149)
* mysqld, enable-named-pipe option:      server-options.     (line  537)
* mysqld, enable-pstack option:          server-options.     (line  551)
* mysqld, exit-info option:              server-options.     (line  596)
* mysqld, external-locking option:       server-options.     (line  613)
* mysqld, flush option:                  server-options.     (line  639)
* mysqld, gdb option:                    server-options.     (line  659)
* mysqld, help option:                   server-options.     (line   70)
* mysqld, init-file option:              server-options.     (line  676)
* mysqld, innodb option:                 innodb-parameters.  (line  112)
* mysqld, innodb-safe-binlog option:     server-options.     (line  700)
* mysqld, innodb-status-file option:     innodb-parameters.  (line  123)
* mysqld, install option:                server-options.     (line  726)
* mysqld, install-manual option:         server-options.     (line  737)
* mysqld, language option:               server-options.     (line  749)
* mysqld, large-pages option:            server-options.     (line  774)
* mysqld, local-infile option:           privileges-options. (line   51)
* mysqld, log option:                    server-options.     (line  807)
* mysqld, log-bin option:                replication-options-binary-log.
                                                             (line   20)
* mysqld, log-bin-index option:          replication-options-binary-log.
                                                             (line   50)
* mysqld, log-bin-trust-function-creators option: replication-options-binary-log.
                                                             (line   67)
* mysqld, log-bin-trust-routine-creators option: replication-options-binary-log.
                                                             (line   94)
* mysqld, log-error option:              server-options.     (line  832)
* mysqld, log-isam option:               server-options.     (line  854)
* mysqld, log-long-format option:        server-options.     (line  869)
* mysqld, log-queries-not-using-indexes option: server-options.
                                                             (line  887)
* mysqld, log-short-format option:       server-options.     (line  911)
* mysqld, log-slave-updates option:      replication-options-slave.
                                                             (line  164)
* mysqld, log-slow-admin-statements option: server-options.  (line  927)
* mysqld, log-slow-queries option:       server-options.     (line  943)
* mysqld, log-tc option:                 server-options.     (line  967)
* mysqld, log-tc-size option:            server-options.     (line  987)
* mysqld, log-warnings option <1>:       replication-options-slave.
                                                             (line  199)
* mysqld, log-warnings option:           server-options.     (line 1012)
* mysqld, low-priority-updates option:   server-options.     (line 1051)
* mysqld, master-connect-retry option:   replication-options-slave.
                                                             (line  235)
* mysqld, master-host option:            replication-options-slave.
                                                             (line  257)
* mysqld, master-info-file option:       replication-options-slave.
                                                             (line  273)
* mysqld, master-password option:        replication-options-slave.
                                                             (line  291)
* mysqld, master-port option:            replication-options-slave.
                                                             (line  308)
* mysqld, master-retry-count option:     replication-options-slave.
                                                             (line  325)
* mysqld, master-ssl option:             replication-options-slave.
                                                             (line  358)
* mysqld, master-ssl-ca option:          replication-options-slave.
                                                             (line  358)
* mysqld, master-ssl-capath option:      replication-options-slave.
                                                             (line  358)
* mysqld, master-ssl-cert option:        replication-options-slave.
                                                             (line  358)
* mysqld, master-ssl-cipher option:      replication-options-slave.
                                                             (line  358)
* mysqld, master-ssl-key option:         replication-options-slave.
                                                             (line  358)
* mysqld, master-user option:            replication-options-slave.
                                                             (line  370)
* mysqld, max-binlog-dump-events option: replication-options-binary-log.
                                                             (line  241)
* mysqld, max-relay-log-size option:     replication-options-slave.
                                                             (line  389)
* mysqld, memlock option:                server-options.     (line 1078)
* mysqld, myisam-block-size option:      server-options.     (line 1122)
* mysqld, myisam-recover option <1>:     myisam-start.       (line   38)
* mysqld, myisam-recover option:         server-options.     (line 1139)
* mysqld, MySQL server <1>:              mysqld-server.      (line   18)
* mysqld, MySQL server:                  mysqld.             (line    6)
* mysqld, ndb-connectstring option:      mysql-cluster-program-options-mysqld.
                                                             (line   23)
* mysqld, ndb-nodeid:                    mysql-cluster-program-options-mysqld.
                                                             (line   79)
* mysqld, ndbcluster option:             mysql-cluster-program-options-mysqld.
                                                             (line   57)
* mysqld, old-passwords option <1>:      privileges-options. (line   57)
* mysqld, old-passwords option:          server-options.     (line 1192)
* mysqld, old-style-user-limits option:  server-options.     (line 1214)
* mysqld, one-thread option:             server-options.     (line 1232)
* mysqld, open-files-limit option:       server-options.     (line 1244)
* mysqld, pid-file option:               server-options.     (line 1276)
* mysqld, port option:                   server-options.     (line 1299)
* mysqld, port-open-timeout option:      server-options.     (line 1321)
* mysqld, read-only option:              replication-options-slave.
                                                             (line  395)
* mysqld, relay-log option:              replication-options-slave.
                                                             (line  403)
* mysqld, relay-log-index option:        replication-options-slave.
                                                             (line  448)
* mysqld, relay-log-info-file option:    replication-options-slave.
                                                             (line  485)
* mysqld, relay-log-purge option:        replication-options-slave.
                                                             (line  505)
* mysqld, relay-log-space-limit option:  replication-options-slave.
                                                             (line  512)
* mysqld, remove option:                 server-options.     (line 1341)
* mysqld, replicate-do-db option:        replication-options-slave.
                                                             (line  533)
* mysqld, replicate-do-table option:     replication-options-slave.
                                                             (line  626)
* mysqld, replicate-ignore-db option:    replication-options-slave.
                                                             (line  583)
* mysqld, replicate-ignore-table option: replication-options-slave.
                                                             (line  648)
* mysqld, replicate-rewrite-db option:   replication-options-slave.
                                                             (line  671)
* mysqld, replicate-same-server-id option: replication-options-slave.
                                                             (line  700)
* mysqld, replicate-wild-do-table option: replication-options-slave.
                                                             (line  725)
* mysqld, replicate-wild-ignore-table option: replication-options-slave.
                                                             (line  772)
* mysqld, report-host option:            replication-options-slave.
                                                             (line  798)
* mysqld, report-password option:        replication-options-slave.
                                                             (line  825)
* mysqld, report-port option:            replication-options-slave.
                                                             (line  852)
* mysqld, report-user option:            replication-options-slave.
                                                             (line  876)
* mysqld, role in MySQL Cluster:         mysql-cluster-basics.
                                                             (line    6)
* mysqld, safe-mode option:              server-options.     (line 1351)
* mysqld, safe-show-database option:     server-options.     (line 1362)
* mysqld, safe-user-create option <1>:   privileges-options. (line   63)
* mysqld, safe-user-create option:       server-options.     (line 1383)
* mysqld, secure-auth option <1>:        privileges-options. (line   78)
* mysqld, secure-auth option:            server-options.     (line 1408)
* mysqld, secure-file-priv option <1>:   privileges-options. (line   87)
* mysqld, secure-file-priv option:       server-options.     (line 1428)
* mysqld, server-id option:              replication-options.
                                                             (line   21)
* mysqld, shared-memory option:          server-options.     (line 1452)
* mysqld, shared-memory-base-name option: server-options.    (line 1457)
* mysqld, show-slave-auth-info option:   replication-options-slave.
                                                             (line  903)
* mysqld, skip-bdb option <1>:           bdb-start.          (line   72)
* mysqld, skip-bdb option:               server-options.     (line 1463)
* mysqld, skip-concurrent-insert option: server-options.     (line 1469)
* mysqld, skip-external-locking option:  server-options.     (line 1475)
* mysqld, skip-grant-tables option <1>:  privileges-options. (line   96)
* mysqld, skip-grant-tables option:      server-options.     (line 1484)
* mysqld, skip-host-cache option:        server-options.     (line 1500)
* mysqld, skip-innodb option <1>:        innodb-parameters.  (line  134)
* mysqld, skip-innodb option:            server-options.     (line 1506)
* mysqld, skip-merge option:             server-options.     (line 1513)
* mysqld, skip-name-resolve option <1>:  privileges-options. (line  107)
* mysqld, skip-name-resolve option:      server-options.     (line 1522)
* mysqld, skip-ndbcluster option:        mysql-cluster-program-options-mysqld.
                                                             (line  119)
* mysqld, skip-networking option <1>:    privileges-options. (line  112)
* mysqld, skip-networking option:        server-options.     (line 1529)
* mysqld, skip-safemalloc option:        server-options.     (line 1576)
* mysqld, skip-show-database option <1>: privileges-options. (line  117)
* mysqld, skip-show-database option:     server-options.     (line 1589)
* mysqld, skip-slave-start option:       replication-options-slave.
                                                             (line  920)
* mysqld, skip-stack-trace option:       server-options.     (line 1610)
* mysqld, skip-symbolic-links option:    server-options.     (line 1553)
* mysqld, skip-thread-priority option:   server-options.     (line 1623)
* mysqld, slave-load-tmpdir option:      replication-options-slave.
                                                             (line  957)
* mysqld, slave-net-timeout option:      replication-options-slave.
                                                             (line  979)
* mysqld, slave-skip-errors option:      replication-options-slave.
                                                             (line 1006)
* mysqld, slave_compressed_protocol option: replication-options-slave.
                                                             (line  936)
* mysqld, socket option:                 server-options.     (line 1640)
* mysqld, sporadic-binlog-dump-fail option: replication-options-binary-log.
                                                             (line  256)
* mysqld, sql-mode option:               server-options.     (line 1667)
* mysqld, SSL options <1>:               privileges-options. (line  127)
* mysqld, SSL options:                   server-options.     (line 1537)
* mysqld, standalone option:             server-options.     (line 1543)
* mysqld, starting:                      changing-mysql-user.
                                                             (line    6)
* mysqld, symbolic-links option:         server-options.     (line 1553)
* mysqld, sync-bdb-logs option:          bdb-start.          (line   76)
* mysqld, sysdate-is-now option:         server-options.     (line 1709)
* mysqld, tc-heuristic-recover option:   server-options.     (line 1733)
* mysqld, temp-pool option:              server-options.     (line 1750)
* mysqld, tmpdir option:                 server-options.     (line 1795)
* mysqld, transaction-isolation option:  server-options.     (line 1770)
* mysqld, user option:                   server-options.     (line 1829)
* mysqld, verbose option:                server-options.     (line 1864)
* mysqld, version option:                server-options.     (line 1868)
* mysqld-version option, mysqld_safe:    mysqld-safe.        (line  190)
* mysqld_multi <1>:                      mysqld-multi.       (line    6)
* mysqld_multi:                          programs-overview.  (line   58)
* mysqld_multi, config-file option:      mysqld-multi.       (line  100)
* mysqld_multi, defaults-extra-file option: mysqld-multi.    (line   68)
* mysqld_multi, defaults-file option:    mysqld-multi.       (line   66)
* mysqld_multi, example option:          mysqld-multi.       (line  114)
* mysqld_multi, help option:             mysqld-multi.       (line   96)
* mysqld_multi, log option:              mysqld-multi.       (line  118)
* mysqld_multi, mysqladmin option:       mysqld-multi.       (line  123)
* mysqld_multi, mysqld option:           mysqld-multi.       (line  128)
* mysqld_multi, no-defaults option:      mysqld-multi.       (line   64)
* mysqld_multi, no-log option:           mysqld-multi.       (line  144)
* mysqld_multi, password option:         mysqld-multi.       (line  149)
* mysqld_multi, silent option:           mysqld-multi.       (line  155)
* mysqld_multi, tcp-ip option:           mysqld-multi.       (line  159)
* mysqld_multi, user option:             mysqld-multi.       (line  167)
* mysqld_multi, verbose option:          mysqld-multi.       (line  172)
* mysqld_multi, version option:          mysqld-multi.       (line  176)
* mysqld_safe <1>:                       mysqld-safe.        (line    6)
* mysqld_safe:                           programs-overview.  (line   45)
* mysqld_safe, autoclose option:         mysqld-safe.        (line  133)
* mysqld_safe, basedir option:           mysqld-safe.        (line  145)
* mysqld_safe, core-file-size option:    mysqld-safe.        (line  149)
* mysqld_safe, datadir option:           mysqld-safe.        (line  154)
* mysqld_safe, defaults-extra-file option: mysqld-safe.      (line  158)
* mysqld_safe, defaults-file option:     mysqld-safe.        (line  165)
* mysqld_safe, help option:              mysqld-safe.        (line  129)
* mysqld_safe, ledir option:             mysqld-safe.        (line  171)
* mysqld_safe, log-error option:         mysqld-safe.        (line  177)
* mysqld_safe, mysqld option:            mysqld-safe.        (line  181)
* mysqld_safe, mysqld-version option:    mysqld-safe.        (line  190)
* mysqld_safe, nice option:              mysqld-safe.        (line  201)
* mysqld_safe, no-defaults option:       mysqld-safe.        (line  206)
* mysqld_safe, open-files-limit option:  mysqld-safe.        (line  211)
* mysqld_safe, pid-file option:          mysqld-safe.        (line  218)
* mysqld_safe, port option:              mysqld-safe.        (line  222)
* mysqld_safe, skip-kill-mysqld option:  mysqld-safe.        (line  228)
* mysqld_safe, socket option:            mysqld-safe.        (line  233)
* mysqld_safe, timezone option:          mysqld-safe.        (line  238)
* mysqld_safe, user option:              mysqld-safe.        (line  244)
* mysqldump <1>:                         mysqldump.          (line    6)
* mysqldump <2>:                         programs-overview.  (line  150)
* mysqldump:                             copying-databases.  (line   45)
* mysqldump, add-drop-database option:   mysqldump.          (line  334)
* mysqldump, add-drop-table option:      mysqldump.          (line  343)
* mysqldump, add-locks option:           mysqldump.          (line  348)
* mysqldump, all-databases option:       mysqldump.          (line  355)
* mysqldump, allow-keywords option:      mysqldump.          (line  361)
* mysqldump, character-sets-dir option:  mysqldump.          (line  366)
* mysqldump, comments option:            mysqldump.          (line  371)
* mysqldump, compact option:             mysqldump.          (line  378)
* mysqldump, compatible option:          mysqldump.          (line  393)
* mysqldump, complete-insert option:     mysqldump.          (line  413)
* mysqldump, compress option:            mysqldump.          (line  418)
* mysqldump, create-options option:      mysqldump.          (line  423)
* mysqldump, databases option:           mysqldump.          (line  428)
* mysqldump, debug option:               mysqldump.          (line  437)
* mysqldump, debug-info option:          mysqldump.          (line  443)
* mysqldump, default-character-set option: mysqldump.        (line  448)
* mysqldump, delayed-insert option:      mysqldump.          (line  458)
* mysqldump, delete-master-logs option:  mysqldump.          (line  463)
* mysqldump, disable-keys option:        mysqldump.          (line  470)
* mysqldump, dump-date option:           mysqldump.          (line  479)
* mysqldump, extended-insert option:     mysqldump.          (line  493)
* mysqldump, fields-enclosed-by option <1>: mysqlimport.     (line  152)
* mysqldump, fields-enclosed-by option:  mysqldump.          (line  501)
* mysqldump, fields-escaped-by option <1>: mysqlimport.      (line  156)
* mysqldump, fields-escaped-by option:   mysqldump.          (line  505)
* mysqldump, fields-optionally-enclosed-by option <1>: mysqlimport.
                                                             (line  154)
* mysqldump, fields-optionally-enclosed-by option: mysqldump.
                                                             (line  503)
* mysqldump, fields-terminated-by option <1>: mysqlimport.   (line  150)
* mysqldump, fields-terminated-by option: mysqldump.         (line  499)
* mysqldump, first-slave option:         mysqldump.          (line  511)
* mysqldump, flush-logs option:          mysqldump.          (line  516)
* mysqldump, flush-privileges option:    mysqldump.          (line  528)
* mysqldump, force option:               mysqldump.          (line  536)
* mysqldump, help option:                mysqldump.          (line  330)
* mysqldump, hex-blob option:            mysqldump.          (line  554)
* mysqldump, host option:                mysqldump.          (line  549)
* mysqldump, ignore-table option:        mysqldump.          (line  562)
* mysqldump, insert-ignore option:       mysqldump.          (line  569)
* mysqldump, lines-terminated-by option <1>: mysqlimport.    (line  180)
* mysqldump, lines-terminated-by option: mysqldump.          (line  574)
* mysqldump, lock-all-tables option:     mysqldump.          (line  580)
* mysqldump, lock-tables option:         mysqldump.          (line  587)
* mysqldump, log-error option:           mysqldump.          (line  601)
* mysqldump, master-data option:         mysqldump.          (line  606)
* mysqldump, no-autocommit option:       mysqldump.          (line  682)
* mysqldump, no-create-db option:        mysqldump.          (line  688)
* mysqldump, no-create-info option:      mysqldump.          (line  694)
* mysqldump, no-data option:             mysqldump.          (line  699)
* mysqldump, no-set-names option:        mysqldump.          (line  707)
* mysqldump, opt option:                 mysqldump.          (line  711)
* mysqldump, order-by-primary option:    mysqldump.          (line  725)
* mysqldump, password option:            mysqldump.          (line  732)
* mysqldump, pipe option:                mysqldump.          (line  744)
* mysqldump, port option:                mysqldump.          (line  749)
* mysqldump, problems <1>:               view-restrictions.  (line  111)
* mysqldump, problems:                   mysqldump.          (line 1101)
* mysqldump, protocol option:            mysqldump.          (line  753)
* mysqldump, quick option:               mysqldump.          (line  760)
* mysqldump, quote-names option:         mysqldump.          (line  767)
* mysqldump, result-file option:         mysqldump.          (line  776)
* mysqldump, routines option:            mysqldump.          (line  784)
* mysqldump, set-charset option:         mysqldump.          (line  811)
* mysqldump, single-transaction option:  mysqldump.          (line  817)
* mysqldump, skip-comments option:       mysqldump.          (line  856)
* mysqldump, skip-opt option:            mysqldump.          (line  860)
* mysqldump, socket option:              mysqldump.          (line  864)
* mysqldump, SSL options:                mysqldump.          (line  869)
* mysqldump, tab option:                 mysqldump.          (line  875)
* mysqldump, tables option:              mysqldump.          (line  902)
* mysqldump, triggers option:            mysqldump.          (line  908)
* mysqldump, tz-utc option:              mysqldump.          (line  915)
* mysqldump, user option:                mysqldump.          (line  929)
* mysqldump, using for backups:          using-mysqldump.    (line   14)
* mysqldump, verbose option:             mysqldump.          (line  933)
* mysqldump, version option:             mysqldump.          (line  937)
* mysqldump, views <1>:                  view-restrictions.  (line  111)
* mysqldump, views:                      mysqldump.          (line 1101)
* mysqldump, where option:               mysqldump.          (line  941)
* mysqldump, workarounds <1>:            view-restrictions.  (line  111)
* mysqldump, workarounds:                mysqldump.          (line 1101)
* mysqldump, xml option:                 mysqldump.          (line  953)
* mysqldumpslow <1>:                     mysqldumpslow.      (line    6)
* mysqldumpslow:                         programs-overview.  (line  203)
* mysqldumpslow, debug option:           mysqldumpslow.      (line   53)
* mysqldumpslow, help option:            mysqldumpslow.      (line   45)
* mysqldumpslow, verbose option:         mysqldumpslow.      (line  103)
* mysqlhotcopy <1>:                      mysqlhotcopy.       (line    6)
* mysqlhotcopy:                          programs-overview.  (line  208)
* mysqlhotcopy, addtodest option:        mysqlhotcopy.       (line   84)
* mysqlhotcopy, allowold option:         mysqlhotcopy.       (line   89)
* mysqlhotcopy, checkpoint option:       mysqlhotcopy.       (line   94)
* mysqlhotcopy, chroot option:           mysqlhotcopy.       (line   99)
* mysqlhotcopy, debug option:            mysqlhotcopy.       (line  105)
* mysqlhotcopy, dryrun option:           mysqlhotcopy.       (line  109)
* mysqlhotcopy, flushlog option:         mysqlhotcopy.       (line  113)
* mysqlhotcopy, help option:             mysqlhotcopy.       (line   80)
* mysqlhotcopy, host option:             mysqlhotcopy.       (line  117)
* mysqlhotcopy, keepold option:          mysqlhotcopy.       (line  123)
* mysqlhotcopy, method option:           mysqlhotcopy.       (line  127)
* mysqlhotcopy, noindices option:        mysqlhotcopy.       (line  131)
* mysqlhotcopy, password option:         mysqlhotcopy.       (line  138)
* mysqlhotcopy, port option:             mysqlhotcopy.       (line  148)
* mysqlhotcopy, quiet option:            mysqlhotcopy.       (line  152)
* mysqlhotcopy, record_log_pos option:   mysqlhotcopy.       (line  156)
* mysqlhotcopy, regexp option:           mysqlhotcopy.       (line  161)
* mysqlhotcopy, resetmaster option:      mysqlhotcopy.       (line  166)
* mysqlhotcopy, resetslave option:       mysqlhotcopy.       (line  170)
* mysqlhotcopy, socket option:           mysqlhotcopy.       (line  174)
* mysqlhotcopy, suffix option:           mysqlhotcopy.       (line  178)
* mysqlhotcopy, tmpdir option:           mysqlhotcopy.       (line  182)
* mysqlhotcopy, user option:             mysqlhotcopy.       (line  186)
* mysqlimport <1>:                       load-data.          (line   66)
* mysqlimport <2>:                       mysqlimport.        (line    6)
* mysqlimport <3>:                       programs-overview.  (line  155)
* mysqlimport:                           copying-databases.  (line   45)
* mysqlimport, character-sets-dir option: mysqlimport.       (line  120)
* mysqlimport, columns option:           mysqlimport.        (line  125)
* mysqlimport, compress option:          mysqlimport.        (line  131)
* mysqlimport, debug option:             mysqlimport.        (line  136)
* mysqlimport, default-character-set option: mysqlimport.    (line  141)
* mysqlimport, delete option:            mysqlimport.        (line  146)
* mysqlimport, force option:             mysqlimport.        (line  161)
* mysqlimport, help option:              mysqlimport.        (line  116)
* mysqlimport, host option:              mysqlimport.        (line  167)
* mysqlimport, ignore option:            mysqlimport.        (line  172)
* mysqlimport, ignore-lines option:      mysqlimport.        (line  176)
* mysqlimport, local option:             mysqlimport.        (line  189)
* mysqlimport, lock-tables option:       mysqlimport.        (line  193)
* mysqlimport, low-priority option:      mysqlimport.        (line  198)
* mysqlimport, password option:          mysqlimport.        (line  204)
* mysqlimport, pipe option:              mysqlimport.        (line  216)
* mysqlimport, port option:              mysqlimport.        (line  221)
* mysqlimport, protocol option:          mysqlimport.        (line  225)
* mysqlimport, replace option:           mysqlimport.        (line  232)
* mysqlimport, silent option:            mysqlimport.        (line  242)
* mysqlimport, socket option:            mysqlimport.        (line  246)
* mysqlimport, SSL options:              mysqlimport.        (line  251)
* mysqlimport, user option:              mysqlimport.        (line  257)
* mysqlimport, verbose option:           mysqlimport.        (line  261)
* mysqlimport, version option:           mysqlimport.        (line  265)
* mysqlmanager <1>:                      instance-manager.   (line   16)
* mysqlmanager:                          programs-overview.  (line  213)
* mysqlmanager, angel-pid-file option:   instance-manager-command-options.
                                                             (line   28)
* mysqlmanager, bind-address option:     instance-manager-command-options.
                                                             (line   42)
* mysqlmanager, default-mysqld-path option: instance-manager-command-options.
                                                             (line   46)
* mysqlmanager, defaults-file option:    instance-manager-command-options.
                                                             (line   55)
* mysqlmanager, help option:             instance-manager-command-options.
                                                             (line   24)
* mysqlmanager, install option:          instance-manager-command-options.
                                                             (line   67)
* mysqlmanager, log option:              instance-manager-command-options.
                                                             (line   73)
* mysqlmanager, monitoring-interval option: instance-manager-command-options.
                                                             (line   91)
* mysqlmanager, passwd option:           instance-manager-command-options.
                                                             (line  118)
* mysqlmanager, password-file option:    instance-manager-command-options.
                                                             (line  125)
* mysqlmanager, pid-file option:         instance-manager-command-options.
                                                             (line  133)
* mysqlmanager, port option:             instance-manager-command-options.
                                                             (line  140)
* mysqlmanager, print-defaults option:   instance-manager-command-options.
                                                             (line  145)
* mysqlmanager, remove option:           instance-manager-command-options.
                                                             (line  150)
* mysqlmanager, run-as-service option:   instance-manager-command-options.
                                                             (line  156)
* mysqlmanager, socket option:           instance-manager-command-options.
                                                             (line  162)
* mysqlmanager, standalone option:       instance-manager-command-options.
                                                             (line  168)
* mysqlmanager, user option:             instance-manager-command-options.
                                                             (line  175)
* mysqlmanager, version option:          instance-manager-command-options.
                                                             (line  186)
* mysqlmanager, wait-timeout option:     instance-manager-command-options.
                                                             (line  190)
* mysqlshow <1>:                         mysqlshow.          (line    6)
* mysqlshow:                             programs-overview.  (line  160)
* mysqlshow, character-sets-dir option:  mysqlshow.          (line  106)
* mysqlshow, compress option:            mysqlshow.          (line  111)
* mysqlshow, count option:               mysqlshow.          (line  116)
* mysqlshow, debug option:               mysqlshow.          (line  121)
* mysqlshow, default-character-set option: mysqlshow.        (line  126)
* mysqlshow, help option:                mysqlshow.          (line  102)
* mysqlshow, host option:                mysqlshow.          (line  131)
* mysqlshow, keys option:                mysqlshow.          (line  135)
* mysqlshow, password option:            mysqlshow.          (line  139)
* mysqlshow, pipe option:                mysqlshow.          (line  153)
* mysqlshow, port option:                mysqlshow.          (line  158)
* mysqlshow, protocol option:            mysqlshow.          (line  162)
* mysqlshow, show-table-type option:     mysqlshow.          (line  169)
* mysqlshow, socket option:              mysqlshow.          (line  175)
* mysqlshow, SSL options:                mysqlshow.          (line  180)
* mysqlshow, status option:              mysqlshow.          (line  186)
* mysqlshow, user option:                mysqlshow.          (line  190)
* mysqlshow, verbose option:             mysqlshow.          (line  194)
* mysqlshow, version option:             mysqlshow.          (line  200)
* mysqltest, MySQL Test Suite:           mysql-test-suite.   (line    6)
* NAME_CONST() <1>:                      stored-programs-logging.
                                                             (line  492)
* NAME_CONST():                          miscellaneous-functions.
                                                             (line  163)
* name_file option, comp_err:            comp-err.           (line   53)
* named pipes <1>:                       windows-testing.    (line    6)
* named pipes:                           windows-select-server.
                                                             (line   30)
* named-commands option, mysql:          mysql-command-options.
                                                             (line  274)
* named_pipe system variable:            server-system-variables.
                                                             (line 3445)
* names:                                 identifiers.        (line   12)
* names, case sensitivity:               identifier-case-sensitivity.
                                                             (line    6)
* names, variables:                      user-variables.     (line    6)
* naming, releases of MySQL:             choosing-version.   (line   57)
* NATIONAL CHAR data type:               string-type-overview.
                                                             (line  100)
* NATIONAL VARCHAR data type:            string-type-overview.
                                                             (line  147)
* native backup and restore, backup identifiers: mysql-cluster-backup-using-management-client.
                                                             (line   75)
* native functions, adding:              adding-native-function.
                                                             (line    6)
* native thread support:                 supported-os.       (line    6)
* NATURAL LEFT JOIN:                     join.               (line    6)
* NATURAL LEFT OUTER JOIN:               join.               (line    6)
* NATURAL RIGHT JOIN:                    join.               (line    6)
* NATURAL RIGHT OUTER JOIN:              join.               (line    6)
* NCHAR data type:                       string-type-overview.
                                                             (line  100)
* NDB:                                   faqs-mysql-cluster. (line    6)
* ndb option, perror:                    perror.             (line   44)
* NDB storage engine:                    mysql-cluster.      (line   14)
* NDB storage engine, FAQ:               faqs-mysql-cluster. (line    6)
* NDB tables, and MySQL root user:       mysql-cluster-security-mysql-privileges.
                                                             (line   48)
* NDB utilities, security issues:        mysql-cluster-security-mysql-security-procedures.
                                                             (line   75)
* ndb-connectstring option, mysqld:      mysql-cluster-program-options-mysqld.
                                                             (line   23)
* ndb-connectstring option, ndb_config:  mysql-cluster-programs-ndb-config.
                                                             (line   55)
* ndb-nodeid option, mysqld:             mysql-cluster-program-options-mysqld.
                                                             (line   79)
* ndb_config <1>:                        mysql-cluster-programs-ndb-config.
                                                             (line    6)
* ndb_config:                            mysql-cluster-programs.
                                                             (line   30)
* ndb_config, config-file option:        mysql-cluster-programs-ndb-config.
                                                             (line   66)
* ndb_config, connections option:        mysql-cluster-programs-ndb-config.
                                                             (line  180)
* ndb_config, fields option:             mysql-cluster-programs-ndb-config.
                                                             (line  204)
* ndb_config, host option:               mysql-cluster-programs-ndb-config.
                                                             (line  126)
* ndb_config, id option:                 mysql-cluster-programs-ndb-config.
                                                             (line  155)
* ndb_config, mycnf option:              mysql-cluster-programs-ndb-config.
                                                             (line   84)
* ndb_config, ndb-connectstring option:  mysql-cluster-programs-ndb-config.
                                                             (line   55)
* ndb_config, nodeid option:             mysql-cluster-programs-ndb-config.
                                                             (line  157)
* ndb_config, nodes option:              mysql-cluster-programs-ndb-config.
                                                             (line  162)
* ndb_config, query option:              mysql-cluster-programs-ndb-config.
                                                             (line   97)
* ndb_config, rows option:               mysql-cluster-programs-ndb-config.
                                                             (line  224)
* ndb_config, type option:               mysql-cluster-programs-ndb-config.
                                                             (line  186)
* ndb_config, usage option:              mysql-cluster-programs-ndb-config.
                                                             (line   34)
* ndb_config, version option:            mysql-cluster-programs-ndb-config.
                                                             (line   45)
* ndb_cpcd <1>:                          mysql-cluster-programs-ndb-cpcd.
                                                             (line    6)
* ndb_cpcd:                              mysql-cluster-programs.
                                                             (line   30)
* ndb_delete_all <1>:                    mysql-cluster-programs-ndb-delete-all.
                                                             (line    6)
* ndb_delete_all:                        mysql-cluster-programs.
                                                             (line   30)
* ndb_delete_all, transactional option:  mysql-cluster-programs-ndb-delete-all.
                                                             (line   21)
* ndb_desc <1>:                          mysql-cluster-programs-ndb-desc.
                                                             (line    6)
* ndb_desc:                              mysql-cluster-programs.
                                                             (line   30)
* ndb_desc, extra-partition-info option: mysql-cluster-programs-ndb-desc.
                                                             (line   72)
* ndb_drop_index <1>:                    mysql-cluster-programs-ndb-drop-index.
                                                             (line    6)
* ndb_drop_index:                        mysql-cluster-programs.
                                                             (line   30)
* ndb_drop_table <1>:                    mysql-cluster-programs-ndb-drop-table.
                                                             (line    6)
* ndb_drop_table:                        mysql-cluster-programs.
                                                             (line   30)
* ndb_error_reporter <1>:                mysql-cluster-programs-ndb-error-reporter.
                                                             (line    6)
* ndb_error_reporter:                    mysql-cluster-programs.
                                                             (line   30)
* ndb_mgm <1>:                           mysql-cluster-programs-ndb-mgm.
                                                             (line    6)
* ndb_mgm:                               mysql-cluster-programs.
                                                             (line   30)
* ndb_mgm (MySQL Cluster management node client): mysql-cluster-install-first-start.
                                                             (line   36)
* ndb_mgmd <1>:                          mysql-cluster-programs-ndb-mgmd.
                                                             (line    6)
* ndb_mgmd:                              mysql-cluster-programs.
                                                             (line   30)
* ndb_mgmd (MySQL Cluster process):      mysql-cluster-programs-ndb-mgmd.
                                                             (line    6)
* ndb_mgmd (MySQL Cluster), defined:     mysql-cluster-basics.
                                                             (line    6)
* ndb_mgmd, mycnf option:                mysql-cluster-programs-ndb-mgmd.
                                                             (line   74)
* ndb_print_backup_file <1>:             mysql-cluster-programs-ndb-print-backup-file.
                                                             (line    6)
* ndb_print_backup_file:                 mysql-cluster-programs.
                                                             (line   30)
* ndb_print_schema_file <1>:             mysql-cluster-programs-ndb-print-schema-file.
                                                             (line    6)
* ndb_print_schema_file:                 mysql-cluster-programs.
                                                             (line   30)
* ndb_print_sys_file <1>:                mysql-cluster-programs-ndb-print-sys-file.
                                                             (line    6)
* ndb_print_sys_file:                    mysql-cluster-programs.
                                                             (line   30)
* ndb_restore:                           mysql-cluster-programs-ndb-restore.
                                                             (line    6)
* ndb_restore, -append option:           mysql-cluster-programs-ndb-restore.
                                                             (line  318)
* ndb_restore, -dont_ignore_systab_0 option: mysql-cluster-programs-ndb-restore.
                                                             (line  179)
* ndb_restore, -fields-enclosed-by option: mysql-cluster-programs-ndb-restore.
                                                             (line  244)
* ndb_restore, -fields-optionally-enclosed-by option: mysql-cluster-programs-ndb-restore.
                                                             (line  259)
* ndb_restore, -fields-terminated-by option: mysql-cluster-programs-ndb-restore.
                                                             (line  276)
* ndb_restore, -hex option:              mysql-cluster-programs-ndb-restore.
                                                             (line  292)
* ndb_restore, -parallelism option:      mysql-cluster-programs-ndb-restore.
                                                             (line  188)
* ndb_restore, -print option:            mysql-cluster-programs-ndb-restore.
                                                             (line  212)
* ndb_restore, -print_data option:       mysql-cluster-programs-ndb-restore.
                                                             (line  218)
* ndb_restore, -print_log option:        mysql-cluster-programs-ndb-restore.
                                                             (line  207)
* ndb_restore, -print_metadata option:   mysql-cluster-programs-ndb-restore.
                                                             (line  202)
* ndb_restore, -tab option:              mysql-cluster-programs-ndb-restore.
                                                             (line  231)
* ndb_restore, -verbose option:          mysql-cluster-programs-ndb-restore.
                                                             (line  334)
* ndb_restore, errors:                   mysql-cluster-programs-ndb-restore.
                                                             (line  353)
* ndb_select_all <1>:                    mysql-cluster-programs-ndb-select-all.
                                                             (line    6)
* ndb_select_all:                        mysql-cluster-programs.
                                                             (line   30)
* ndb_select_all, delimiter option:      mysql-cluster-programs-ndb-select-all.
                                                             (line   49)
* ndb_select_all, descending option:     mysql-cluster-programs-ndb-select-all.
                                                             (line   34)
* ndb_select_all, gci option:            mysql-cluster-programs-ndb-select-all.
                                                             (line   61)
* ndb_select_all, header option:         mysql-cluster-programs-ndb-select-all.
                                                             (line   39)
* ndb_select_all, lock option:           mysql-cluster-programs-ndb-select-all.
                                                             (line   15)
* ndb_select_all, nodata option:         mysql-cluster-programs-ndb-select-all.
                                                             (line   72)
* ndb_select_all, order option:          mysql-cluster-programs-ndb-select-all.
                                                             (line   28)
* ndb_select_all, rowid option:          mysql-cluster-programs-ndb-select-all.
                                                             (line   56)
* ndb_select_all, tupscan option:        mysql-cluster-programs-ndb-select-all.
                                                             (line   68)
* ndb_select_all, useHexFormat option:   mysql-cluster-programs-ndb-select-all.
                                                             (line   43)
* ndb_select_count <1>:                  mysql-cluster-programs-ndb-select-count.
                                                             (line    6)
* ndb_select_count:                      mysql-cluster-programs.
                                                             (line   30)
* ndb_show_tables <1>:                   mysql-cluster-programs-ndb-show-tables.
                                                             (line    6)
* ndb_show_tables:                       mysql-cluster-programs.
                                                             (line   30)
* ndb_show_tables, database option:      mysql-cluster-programs-ndb-show-tables.
                                                             (line   36)
* ndb_show_tables, loops option:         mysql-cluster-programs-ndb-show-tables.
                                                             (line   40)
* ndb_show_tables, parsable option:      mysql-cluster-programs-ndb-show-tables.
                                                             (line   46)
* ndb_show_tables, show-temp-status option: mysql-cluster-programs-ndb-show-tables.
                                                             (line   51)
* ndb_show_tables, type option:          mysql-cluster-programs-ndb-show-tables.
                                                             (line   55)
* ndb_show_tables, unqualified option:   mysql-cluster-programs-ndb-show-tables.
                                                             (line   69)
* ndb_size.pl <1>:                       mysql-cluster-programs-ndb-size-pl.
                                                             (line    6)
* ndb_size.pl:                           mysql-cluster-programs.
                                                             (line   30)
* ndb_size.pl (utility):                 faqs-mysql-cluster. (line    6)
* ndb_waiter <1>:                        mysql-cluster-programs-ndb-waiter.
                                                             (line    6)
* ndb_waiter:                            mysql-cluster-programs.
                                                             (line   30)
* ndb_waiter, no-contact option:         mysql-cluster-programs-ndb-waiter.
                                                             (line   57)
* ndb_waiter, not-started option:        mysql-cluster-programs-ndb-waiter.
                                                             (line   63)
* ndb_waiter, single-user option:        mysql-cluster-programs-ndb-waiter.
                                                             (line   75)
* ndb_waiter, timeout option:            mysql-cluster-programs-ndb-waiter.
                                                             (line   69)
* ndbcluster option, mysqld:             mysql-cluster-program-options-mysqld.
                                                             (line   57)
* ndbd <1>:                              mysql-cluster-programs-ndbd.
                                                             (line    6)
* ndbd:                                  mysql-cluster-programs.
                                                             (line   30)
* ndbd (MySQL Cluster), defined:         mysql-cluster-basics.
                                                             (line    6)
* negative values:                       number-literals.    (line    6)
* nested queries:                        subqueries.         (line   20)
* nested-loop join algorithm:            nested-join-optimization.
                                                             (line  172)
* Nested-Loop join algorithm:            nested-loop-joins.  (line    6)
* net etiquette:                         mailing-list-use.   (line    6)
* net_buffer_length system variable:     server-system-variables.
                                                             (line 3461)
* net_buffer_length variable:            mysql-command-options.
                                                             (line  595)
* net_read_timeout system variable:      server-system-variables.
                                                             (line 3498)
* net_retry_count system variable:       server-system-variables.
                                                             (line 3530)
* net_write_timeout system variable:     server-system-variables.
                                                             (line 3571)
* netmask notation, in account names:    account-names.      (line   88)
* NetWare:                               netware-installation.
                                                             (line    6)
* network ports, and MySQL Cluster:      mysql-cluster-security-networking-issues.
                                                             (line  182)
* new features in MySQL 5.0:             mysql-nutshell.     (line    6)
* new features in MySQL Cluster:         mysql-cluster-development.
                                                             (line   10)
* new procedures, adding:                adding-procedures.  (line   11)
* new system variable:                   server-system-variables.
                                                             (line 3599)
* new users, adding <1>:                 unix-postinstallation.
                                                             (line  363)
* new users, adding:                     installing-source-distribution.
                                                             (line  198)
* newline (\n) <1>:                      load-data.          (line  416)
* newline (\n):                          string-literals.    (line   72)
* next-key lock, InnoDB <1>:             innodb-next-key-locking.
                                                             (line    6)
* next-key lock, InnoDB <2>:             innodb-record-level-locks.
                                                             (line    6)
* next-key lock, InnoDB <3>:             innodb-transaction-model.
                                                             (line   65)
* next-key lock, InnoDB:                 innodb-parameters.  (line  707)
* NFS, InnoDB <1>:                       innodb-restrictions.
                                                             (line   16)
* NFS, InnoDB:                           innodb-configuration.
                                                             (line   50)
* nice option, mysqld_safe:              mysqld-safe.        (line  201)
* no matching rows:                      no-matching-rows.   (line    6)
* no-auto-rehash option, mysql:          mysql-command-options.
                                                             (line  281)
* no-autocommit option, mysqldump:       mysqldump.          (line  682)
* no-beep option, mysql:                 mysql-command-options.
                                                             (line  286)
* no-contact option, ndb_waiter:         mysql-cluster-programs-ndb-waiter.
                                                             (line   57)
* no-create-db option, mysqldump:        mysqldump.          (line  688)
* no-create-info option, mysqldump:      mysqldump.          (line  694)
* no-data option, mysqldump:             mysqldump.          (line  699)
* no-debug option, make_win_bin_dist:    make-win-bin-dist.  (line   52)
* no-defaults option:                    option-file-options.
                                                             (line   45)
* no-defaults option, my_print_defaults: my-print-defaults.  (line   53)
* no-defaults option, mysqld_multi:      mysqld-multi.       (line   64)
* no-defaults option, mysqld_safe:       mysqld-safe.        (line  206)
* no-embedded option, make_win_bin_dist: make-win-bin-dist.  (line   56)
* no-log option, mysqld_multi:           mysqld-multi.       (line  144)
* no-named-commands option, mysql:       mysql-command-options.
                                                             (line  290)
* no-pager option, mysql:                mysql-command-options.
                                                             (line  295)
* no-set-names option, mysqldump:        mysqldump.          (line  707)
* no-symlinks option, myisamchk:         myisamchk-repair-options.
                                                             (line   54)
* no-tee option, mysql:                  mysql-command-options.
                                                             (line  300)
* NO_AUTO_CREATE_USER SQL mode:          server-sql-mode.    (line  154)
* NO_AUTO_VALUE_ON_ZERO SQL mode:        server-sql-mode.    (line  160)
* NO_BACKSLASH_ESCAPES SQL mode:         server-sql-mode.    (line  179)
* NO_DIR_IN_CREATE SQL mode:             server-sql-mode.    (line  186)
* NO_ENGINE_SUBSTITUTION SQL mode:       server-sql-mode.    (line  192)
* NO_FIELD_OPTIONS SQL mode:             server-sql-mode.    (line  209)
* NO_KEY_OPTIONS SQL mode:               server-sql-mode.    (line  215)
* NO_TABLE_OPTIONS SQL mode:             server-sql-mode.    (line  221)
* NO_UNSIGNED_SUBTRACTION SQL mode:      server-sql-mode.    (line  227)
* NO_ZERO_DATE SQL mode:                 server-sql-mode.    (line  274)
* NO_ZERO_IN_DATE SQL mode:              server-sql-mode.    (line  281)
* nodata option, ndb_select_all:         mysql-cluster-programs-ndb-select-all.
                                                             (line   72)
* node groups (MySQL Cluster):           mysql-cluster-nodes-groups.
                                                             (line    6)
* node identifiers (MySQL Cluster) <1>:  mysql-cluster-sci-definition.
                                                             (line   26)
* node identifiers (MySQL Cluster):      mysql-cluster-shm-definition.
                                                             (line   27)
* node logs (MySQL Cluster):             mysql-cluster-event-reports.
                                                             (line   12)
* NodeId <1>:                            mysql-cluster-api-definition.
                                                             (line   49)
* NodeId <2>:                            mysql-cluster-ndbd-definition.
                                                             (line   59)
* NodeId:                                mysql-cluster-mgm-definition.
                                                             (line   39)
* nodeid option, ndb_config:             mysql-cluster-programs-ndb-config.
                                                             (line  157)
* NodeId1:                               mysql-cluster-tcp-definition.
                                                             (line   37)
* NodeId2:                               mysql-cluster-tcp-definition.
                                                             (line   48)
* NODERESTART Events (MySQL Cluster):    mysql-cluster-log-events.
                                                             (line   92)
* nodes option, ndb_config:              mysql-cluster-programs-ndb-config.
                                                             (line  162)
* noindices option, mysqlhotcopy:        mysqlhotcopy.       (line  131)
* nondelimited strings:                  date-and-time-literals.
                                                             (line  116)
* Nontransactional tables:               non-transactional-tables.
                                                             (line    6)
* NoOfDiskPagesToDiskAfterRestartACC:    mysql-cluster-ndbd-definition.
                                                             (line 1599)
* NoOfDiskPagesToDiskAfterRestartACC, calculating: mysql-cluster-config-lcp-params.
                                                             (line    6)
* NoOfDiskPagesToDiskAfterRestartTUP:    mysql-cluster-ndbd-definition.
                                                             (line 1562)
* NoOfDiskPagesToDiskAfterRestartTUP, calculating: mysql-cluster-config-lcp-params.
                                                             (line    6)
* NoOfDiskPagesToDiskDuringRestartACC:   mysql-cluster-ndbd-definition.
                                                             (line 1644)
* NoOfDiskPagesToDiskDuringRestartTUP:   mysql-cluster-ndbd-definition.
                                                             (line 1619)
* NoOfFragmentLogFiles:                  mysql-cluster-ndbd-definition.
                                                             (line  863)
* NoOfFragmentLogFiles, calculating:     mysql-cluster-config-lcp-params.
                                                             (line    6)
* NoOfReplicas:                          mysql-cluster-ndbd-definition.
                                                             (line  143)
* nopager command, mysql:                mysql-commands.     (line  143)
* NOT BETWEEN:                           comparison-operators.
                                                             (line  227)
* not equal (!=):                        comparison-operators.
                                                             (line   91)
* not equal (<>):                        comparison-operators.
                                                             (line   91)
* NOT EXISTS, with subqueries:           exists-and-not-exists-subqueries.
                                                             (line    6)
* NOT IN:                                comparison-operators.
                                                             (line  297)
* NOT LIKE:                              string-comparison-functions.
                                                             (line  156)
* NOT NULL, constraint:                  constraint-invalid-data.
                                                             (line    6)
* NOT REGEXP:                            regexp.             (line   28)
* NOT, logical:                          logical-operators.  (line   29)
* not-started option, ndb_waiter:        mysql-cluster-programs-ndb-waiter.
                                                             (line   63)
* notee command, mysql:                  mysql-commands.     (line  149)
* Novell NetWare:                        netware-installation.
                                                             (line    6)
* NOW():                                 date-and-time-functions.
                                                             (line  709)
* NOWAIT (START BACKUP command):         mysql-cluster-backup-using-management-client.
                                                             (line   36)
* nowarning command, mysql:              mysql-commands.     (line  154)
* NUL <1>:                               load-data.          (line  414)
* NUL:                                   string-literals.    (line   68)
* NULL <1>:                              problems-with-null. (line    6)
* NULL:                                  working-with-null.  (line    6)
* NULL value <1>:                        null-values.        (line    6)
* NULL value:                            working-with-null.  (line    6)
* NULL values, and AUTO_INCREMENT columns: problems-with-null.
                                                             (line   71)
* NULL values, and indexes:              create-table.       (line  338)
* NULL values, and TIMESTAMP columns:    problems-with-null. (line   71)
* NULL values, vs. empty values:         problems-with-null. (line    6)
* NULL, ORDER BY <1>:                    select.             (line  197)
* NULL, ORDER BY:                        order-by-optimization.
                                                             (line   94)
* NULL, testing for null <1>:            control-flow-functions.
                                                             (line   85)
* NULL, testing for null:                comparison-operators.
                                                             (line   79)
* NULL, thread state:                    general-thread-states.
                                                             (line  175)
* NULLIF():                              control-flow-functions.
                                                             (line  119)
* numbers:                               number-literals.    (line    6)
* NUMERIC data type:                     numeric-type-overview.
                                                             (line  220)
* numeric precision:                     data-types.         (line   31)
* numeric scale:                         data-types.         (line   37)
* numeric types:                         storage-requirements.
                                                             (line   83)
* numeric-dump-file option, resolve_stack_dump: resolve-stack-dump.
                                                             (line   25)
* NumGeometries():                       geometrycollection-property-functions.
                                                             (line   21)
* NumInteriorRings():                    polygon-property-functions.
                                                             (line   49)
* NumPoints():                           linestring-property-functions.
                                                             (line   39)
* NVARCHAR data type:                    string-type-overview.
                                                             (line  147)
* OCT():                                 string-functions.   (line  489)
* OCTET_LENGTH():                        string-functions.   (line  498)
* ODBC:                                  connector-odbc.     (line   17)
* ODBC compatibility <1>:                join.               (line  145)
* ODBC compatibility <2>:                create-table.       (line  222)
* ODBC compatibility <3>:                comparison-operators.
                                                             (line  157)
* ODBC compatibility <4>:                type-conversion.    (line   44)
* ODBC compatibility <5>:                numeric-type-overview.
                                                             (line  287)
* ODBC compatibility <6>:                identifier-qualifiers.
                                                             (line   41)
* ODBC compatibility:                    server-system-variables.
                                                             (line 4585)
* offset option, mysqlbinlog:            mysqlbinlog.        (line  252)
* OLAP:                                  group-by-modifiers. (line    6)
* old-passwords option, mysqld <1>:      privileges-options. (line   57)
* old-passwords option, mysqld:          server-options.     (line 1192)
* old-style-user-limits option, mysqld:  server-options.     (line 1214)
* OLD_PASSWORD():                        encryption-functions.
                                                             (line  288)
* old_passwords system variable:         server-system-variables.
                                                             (line 3623)
* old_server option, mysqlaccess:        mysqlaccess.        (line  103)
* ON DUPLICATE KEY:                      insert.             (line   12)
* one-database option, mysql:            mysql-command-options.
                                                             (line  305)
* one-thread option, mysqld:             server-options.     (line 1232)
* one_shot system variable:              server-system-variables.
                                                             (line 3644)
* online location of manual:             manual-info.        (line    6)
* online upgrades and downgrades (MySQL Cluster): mysql-cluster-rolling-restart.
                                                             (line    6)
* online upgrades and downgrades (MySQL Cluster), order of node updates: mysql-cluster-rolling-restart.
                                                             (line   96)
* only-debug option, make_win_bin_dist:  make-win-bin-dist.  (line   60)
* ONLY_FULL_GROUP_BY SQL mode:           server-sql-mode.    (line  290)
* ONLY_FULL_GROUP_BY, SQL mode:          group-by-hidden-columns.
                                                             (line    6)
* OPEN:                                  open.               (line    6)
* Open Source, defined:                  what-is-mysql.      (line   39)
* open tables <1>:                       table-cache.        (line    6)
* open tables:                           mysqladmin.         (line  188)
* open-files-limit option, mysqld:       server-options.     (line 1244)
* open-files-limit option, mysqld_safe:  mysqld-safe.        (line  211)
* open_files_limit system variable:      server-system-variables.
                                                             (line 3649)
* open_files_limit variable:             mysqlbinlog.        (line  377)
* OpenGIS:                               gis-introduction.   (line    6)
* Opening master dump table, thread state: slave-connection-thread-states.
                                                             (line   25)
* Opening mysql.ndb_apply_status, thread state: mysql-cluster-thread-states.
                                                             (line    8)
* Opening table, thread state:           general-thread-states.
                                                             (line  185)
* Opening tables, thread state:          general-thread-states.
                                                             (line  185)
* opening, tables:                       table-cache.        (line    6)
* opens:                                 mysqladmin.         (line  179)
* OpenSSL <1>:                           secure-using-ssl.   (line    6)
* OpenSSL:                               secure-connections. (line   13)
* operating systems, file-size limits:   table-size-limit.   (line    6)
* operating systems, supported:          supported-os.       (line    6)
* operations, arithmetic:                arithmetic-functions.
                                                             (line   55)
* operators:                             functions.          (line   26)
* operators, assignment <1>:             assignment-operators.
                                                             (line    6)
* operators, assignment:                 user-variables.     (line    6)
* operators, cast <1>:                   cast-functions.     (line    6)
* operators, cast:                       arithmetic-functions.
                                                             (line    6)
* operators, logical:                    logical-operators.  (line    6)
* operators, precedence:                 operator-precedence.
                                                             (line    6)
* opt option, mysqldump:                 mysqldump.          (line  711)
* optimization, subquery:                in-subquery-optimization.
                                                             (line    6)
* optimization, tips:                    miscellaneous-optimization-tips.
                                                             (line    6)
* optimizations <1>:                     index-merge-optimization.
                                                             (line   12)
* optimizations:                         where-optimizations.
                                                             (line    6)
* optimize option, mysqlcheck:           mysqlcheck.         (line  272)
* OPTIMIZE TABLE:                        optimize-table.     (line    6)
* optimizer, and replication:            replication-features-optimizer.
                                                             (line    6)
* optimizer, controlling:                controlling-optimizer.
                                                             (line    6)
* optimizer_prune_level system variable: server-system-variables.
                                                             (line 3675)
* optimizer_search_depth system variable: server-system-variables.
                                                             (line 3701)
* optimizing, DISTINCT:                  distinct-optimization.
                                                             (line    6)
* optimizing, filesort:                  order-by-optimization.
                                                             (line  113)
* optimizing, GROUP BY:                  group-by-optimization.
                                                             (line   11)
* optimizing, LEFT JOIN:                 left-join-optimization.
                                                             (line    6)
* optimizing, LIMIT:                     limit-optimization. (line    6)
* optimizing, tables:                    myisam-optimization.
                                                             (line    6)
* optimizing, thread state:              general-thread-states.
                                                             (line  194)
* option files <1>:                      access-denied.      (line  101)
* option files:                          option-files.       (line   11)
* option files, escape sequences:        option-files.       (line  161)
* option prefix, -disable:               option-modifiers.   (line    6)
* option prefix, -enable:                option-modifiers.   (line    6)
* option prefix, -loose:                 option-modifiers.   (line    6)
* option prefix, -maximum:               option-modifiers.   (line    6)
* option prefix, -skip:                  option-modifiers.   (line    6)
* options, boolean:                      option-modifiers.   (line    6)
* options, command-line, mysql:          mysql-command-options.
                                                             (line    6)
* options, command-line, mysqladmin:     mysqladmin.         (line  209)
* options, configure:                    source-configuration-options.
                                                             (line    6)
* options, myisamchk:                    myisamchk-general-options.
                                                             (line    6)
* options, provided by MySQL:            tutorial.           (line   16)
* options, replication:                  replication-features.
                                                             (line   37)
* OR <1>:                                index-merge-optimization.
                                                             (line   12)
* OR:                                    searching-on-two-keys.
                                                             (line    6)
* OR Index Merge optimization:           index-merge-optimization.
                                                             (line   12)
* OR, bitwise:                           bit-functions.      (line   20)
* OR, logical:                           logical-operators.  (line   68)
* Oracle compatibility <1>:              describe.           (line   40)
* Oracle compatibility <2>:              alter-table.        (line  205)
* Oracle compatibility <3>:              group-by-functions. (line  245)
* Oracle compatibility:                  extensions-to-ansi. (line   99)
* ORACLE SQL mode:                       server-sql-mode.    (line  430)
* ORD():                                 string-functions.   (line  502)
* ORDER BY <1>:                          select.             (line  169)
* ORDER BY <2>:                          alter-table.        (line  286)
* ORDER BY:                              sorting-rows.       (line    6)
* ORDER BY, NULL <1>:                    select.             (line  197)
* ORDER BY, NULL:                        order-by-optimization.
                                                             (line   94)
* order option, ndb_select_all:          mysql-cluster-programs-ndb-select-all.
                                                             (line   28)
* order-by-primary option, mysqldump:    mysqldump.          (line  725)
* out-of-range handling:                 out-of-range-and-overflow.
                                                             (line    6)
* out_dir option, comp_err:              comp-err.           (line   57)
* out_file option, comp_err:             comp-err.           (line   62)
* OUTFILE:                               select-into.        (line   24)
* overflow handling:                     out-of-range-and-overflow.
                                                             (line    6)
* Overlaps():                            functions-that-test-spatial-relationships-between-geometries.
                                                             (line   53)
* overview:                              introduction.       (line   18)
* packages, list of:                     packages.           (line    6)
* page size, InnoDB <1>:                 innodb-restrictions.
                                                             (line   71)
* page size, InnoDB:                     innodb-physical-structure.
                                                             (line    6)
* page-level locking:                    internal-locking.   (line    6)
* pager command, mysql:                  mysql-commands.     (line  159)
* pager option, mysql:                   mysql-command-options.
                                                             (line  348)
* parallel-recover option, myisamchk:    myisamchk-repair-options.
                                                             (line   66)
* parameters, server:                    server-parameters.  (line    6)
* parentheses ( and ):                   operator-precedence.
                                                             (line   49)
* parsable option, ndb_show_tables:      mysql-cluster-programs-ndb-show-tables.
                                                             (line   46)
* partial updates, and replication:      replication-features-slaveerrors.
                                                             (line    6)
* partitions (MySQL Cluster):            mysql-cluster-nodes-groups.
                                                             (line    6)
* passwd option, mysqlmanager:           instance-manager-command-options.
                                                             (line  118)
* password encryption, reversibility of: encryption-functions.
                                                             (line  309)
* password option:                       connecting.         (line  134)
* password option, mysql:                mysql-command-options.
                                                             (line  357)
* password option, mysql_convert_table_format: mysql-convert-table-format.
                                                             (line   36)
* password option, mysql_explain_log:    mysql-explain-log.  (line   37)
* password option, mysql_setpermission:  mysql-setpermission.
                                                             (line   37)
* password option, mysql_tableinfo:      mysql-tableinfo.    (line  103)
* password option, mysqlaccess:          mysqlaccess.        (line  108)
* password option, mysqladmin:           mysqladmin.         (line  325)
* password option, mysqlbinlog:          mysqlbinlog.        (line  256)
* password option, mysqlcheck:           mysqlcheck.         (line  276)
* password option, mysqld_multi:         mysqld-multi.       (line  149)
* password option, mysqldump:            mysqldump.          (line  732)
* password option, mysqlhotcopy:         mysqlhotcopy.       (line  138)
* password option, mysqlimport:          mysqlimport.        (line  204)
* password option, mysqlshow:            mysqlshow.          (line  139)
* PASSWORD() <1>:                        ignoring-user.      (line   26)
* PASSWORD() <2>:                        encryption-functions.
                                                             (line  298)
* PASSWORD() <3>:                        assigning-passwords.
                                                             (line    6)
* PASSWORD():                            connection-access.  (line   38)
* password, root user:                   default-privileges. (line    6)
* password-file option, mysqlmanager:    instance-manager-command-options.
                                                             (line  125)
* passwords, administrator guidelines:   password-security-admin.
                                                             (line    6)
* passwords, for users:                  user-names.         (line    6)
* passwords, forgotten:                  resetting-permissions.
                                                             (line   12)
* passwords, hashing:                    password-hashing.   (line    6)
* passwords, lost:                       resetting-permissions.
                                                             (line   12)
* passwords, resetting:                  resetting-permissions.
                                                             (line   12)
* passwords, security <1>:               privilege-system.   (line   16)
* passwords, security:                   password-security.  (line   13)
* passwords, setting <1>:                set-password.       (line    6)
* passwords, setting <2>:                grant.              (line  391)
* passwords, setting:                    assigning-passwords.
                                                             (line    6)
* passwords, user guidelines:            password-security-user.
                                                             (line    6)
* PATH environment variable <1>:         invoking-programs.  (line   48)
* PATH environment variable <2>:         environment-variables.
                                                             (line   18)
* PATH environment variable:             unix-postinstallation.
                                                             (line   63)
* path name separators, Windows:         option-files.       (line  183)
* pattern matching <1>:                  regexp.             (line    6)
* pattern matching:                      pattern-matching.   (line    6)
* performance, benchmarks:               custom-benchmarks.  (line    6)
* performance, disk I/O:                 disk-issues.        (line    6)
* performance, estimating:               estimating-performance.
                                                             (line    6)
* performance, improving <1>:            replication-faq.    (line   25)
* performance, improving:                data-size.          (line    6)
* PERIOD_ADD():                          date-and-time-functions.
                                                             (line  753)
* PERIOD_DIFF():                         date-and-time-functions.
                                                             (line  762)
* Perl API:                              apis-perl.          (line    6)
* Perl DBI/DBD, installation problems:   perl-support-problems.
                                                             (line    6)
* Perl, installing:                      perl-support.       (line   12)
* Perl, installing on Windows:           activestate-perl.   (line    6)
* permission checks, effect on speed:    select-optimization.
                                                             (line   25)
* perror <1>:                            perror.             (line    6)
* perror:                                programs-overview.  (line  291)
* perror, -ndb option:                   faqs-mysql-cluster. (line    6)
* perror, help option:                   perror.             (line   40)
* perror, ndb option:                    perror.             (line   44)
* perror, silent option:                 perror.             (line   48)
* perror, verbose option:                perror.             (line   52)
* perror, version option:                perror.             (line   57)
* phantom rows:                          innodb-next-key-locking.
                                                             (line    6)
* PHP API:                               apis-php.           (line   12)
* PI():                                  mathematical-functions.
                                                             (line  327)
* pid-file option, mysql.server:         mysql-server.       (line   44)
* pid-file option, mysqld:               server-options.     (line 1276)
* pid-file option, mysqld_safe:          mysqld-safe.        (line  218)
* pid-file option, mysqlmanager:         instance-manager-command-options.
                                                             (line  133)
* pid_file system variable:              server-system-variables.
                                                             (line 3730)
* Ping, thread command:                  thread-commands.    (line   78)
* pipe option:                           connecting.         (line  141)
* pipe option, mysql <1>:                mysqlcheck.         (line  288)
* pipe option, mysql:                    mysql-command-options.
                                                             (line  369)
* pipe option, mysqladmin:               mysqladmin.         (line  337)
* pipe option, mysqldump:                mysqldump.          (line  744)
* pipe option, mysqlimport:              mysqlimport.        (line  216)
* pipe option, mysqlshow:                mysqlshow.          (line  153)
* PIPES_AS_CONCAT SQL mode:              server-sql-mode.    (line  303)
* plan option, mysqlaccess:              mysqlaccess.        (line  117)
* plugin_dir system variable:            server-system-variables.
                                                             (line 3750)
* POINT data type:                       mysql-spatial-datatypes.
                                                             (line    6)
* Point():                               gis-mysql-specific-functions.
                                                             (line   56)
* point-in-time recovery:                point-in-time-recovery.
                                                             (line   11)
* PointFromText():                       gis-wkt-functions.  (line   45)
* PointFromWKB():                        gis-wkb-functions.  (line   48)
* PointN():                              linestring-property-functions.
                                                             (line   51)
* PointOnSurface():                      multipolygon-property-functions.
                                                             (line   32)
* PolyFromText():                        gis-wkt-functions.  (line   49)
* PolyFromWKB():                         gis-wkb-functions.  (line   52)
* POLYGON data type:                     mysql-spatial-datatypes.
                                                             (line    6)
* Polygon():                             gis-mysql-specific-functions.
                                                             (line   60)
* PolygonFromText():                     gis-wkt-functions.  (line   49)
* PolygonFromWKB():                      gis-wkb-functions.  (line   52)
* port option:                           connecting.         (line  147)
* port option, mysql:                    mysql-command-options.
                                                             (line  374)
* port option, mysql_config:             mysql-config.       (line   39)
* port option, mysql_convert_table_format: mysql-convert-table-format.
                                                             (line   46)
* port option, mysql_setpermission:      mysql-setpermission.
                                                             (line   47)
* port option, mysql_tableinfo:          mysql-tableinfo.    (line  113)
* port option, mysqladmin:               mysqladmin.         (line  342)
* port option, mysqlbinlog:              mysqlbinlog.        (line  268)
* port option, mysqlcheck:               mysqlcheck.         (line  293)
* port option, mysqld:                   server-options.     (line 1299)
* port option, mysqld_safe:              mysqld-safe.        (line  222)
* port option, mysqldump:                mysqldump.          (line  749)
* port option, mysqlhotcopy:             mysqlhotcopy.       (line  148)
* port option, mysqlimport:              mysqlimport.        (line  221)
* port option, mysqlmanager:             instance-manager-command-options.
                                                             (line  140)
* port option, mysqlshow:                mysqlshow.          (line  158)
* port system variable:                  server-system-variables.
                                                             (line 3777)
* port-open-timeout option, mysqld:      server-options.     (line 1321)
* portability:                           portability.        (line    6)
* portability, types:                    other-vendor-data-types.
                                                             (line    6)
* porting, to other systems:             porting.            (line   12)
* PortNumber <1>:                        mysql-cluster-tcp-definition.
                                                             (line  151)
* PortNumber:                            mysql-cluster-mgm-definition.
                                                             (line   73)
* position option, mysqlbinlog:          mysqlbinlog.        (line  272)
* POSITION():                            string-functions.   (line  518)
* PostgreSQL compatibility:              extensions-to-ansi. (line  193)
* POSTGRESQL SQL mode:                   server-sql-mode.    (line  436)
* postinstall, multiple servers:         multiple-servers.   (line   13)
* postinstallation, setup and testing:   postinstallation.   (line   11)
* POW():                                 mathematical-functions.
                                                             (line  338)
* POWER():                               mathematical-functions.
                                                             (line  347)
* precedence, operator:                  operator-precedence.
                                                             (line    6)
* precision math:                        precision-math.     (line   14)
* precision, arithmetic:                 precision-math.     (line   14)
* precision, numeric:                    data-types.         (line   31)
* prefix option, configure:              source-configuration-options.
                                                             (line  302)
* prefix option, mysql_tableinfo:        mysql-tableinfo.    (line  117)
* preload_buffer_size system variable:   server-system-variables.
                                                             (line 3798)
* PREPARE <1>:                           prepare.            (line    6)
* PREPARE:                               sql-syntax-prepared-statements.
                                                             (line   12)
* Prepare, thread command:               thread-commands.    (line   82)
* PREPARE, XA transactions:              xa-statements.      (line    6)
* prepared statements <1>:               deallocate-prepare. (line    6)
* prepared statements <2>:               execute.            (line    6)
* prepared statements <3>:               prepare.            (line    6)
* prepared statements:                   sql-syntax-prepared-statements.
                                                             (line   12)
* prepared_stmt_count system variable:   server-system-variables.
                                                             (line 3821)
* preparing, thread state:               general-thread-states.
                                                             (line  198)
* preview option, mysqlaccess:           mysqlaccess.        (line  121)
* PRIMARY KEY <1>:                       create-table.       (line  282)
* PRIMARY KEY:                           alter-table.        (line  266)
* primary key, constraint:               constraint-primary-key.
                                                             (line    6)
* primary key, deleting:                 alter-table.        (line  263)
* print command, mysql:                  mysql-commands.     (line  181)
* print-defaults option:                 option-file-options.
                                                             (line   51)
* print-defaults option, mysqlmanager:   instance-manager-command-options.
                                                             (line  145)
* printerror option, mysql_explain_log:  mysql-explain-log.  (line   44)
* privilege information, location:       grant-table-structure.
                                                             (line    6)
* privilege system:                      privilege-system.   (line   16)
* privilege, changes:                    privilege-changes.  (line    6)
* privileges, access:                    privilege-system.   (line   16)
* privileges, adding:                    adding-users.       (line    6)
* privileges, and replication:           replication-features-userprivs.
                                                             (line    6)
* privileges, default:                   default-privileges. (line    6)
* privileges, deleting <1>:              drop-user.          (line    6)
* privileges, deleting:                  removing-users.     (line    6)
* privileges, display:                   show-grants.        (line    6)
* privileges, dropping <1>:              drop-user.          (line    6)
* privileges, dropping:                  removing-users.     (line    6)
* privileges, granting:                  grant.              (line    6)
* privileges, revoking:                  revoke.             (line    6)
* problems, access denied errors:        error-access-denied.
                                                             (line    6)
* problems, common errors:               problems.           (line   17)
* problems, compiling:                   compilation-problems.
                                                             (line    6)
* problems, DATE columns:                using-date.         (line    6)
* problems, date values:                 datetime.           (line   47)
* problems, installing on IBM-AIX:       ibm-aix.            (line    6)
* problems, installing on Solaris:       solaris.            (line   11)
* problems, installing Perl:             perl-support-problems.
                                                             (line    6)
* problems, linking:                     c-api-linking-problems.
                                                             (line    6)
* problems, lost connection errors:      error-lost-connection.
                                                             (line    6)
* problems, ODBC:                        connector-odbc-support.
                                                             (line   14)
* problems, reporting:                   bug-reports.        (line    6)
* problems, starting the server:         starting-server.    (line    6)
* problems, table locking:               table-locking.      (line    6)
* problems, time zone:                   timezone-problems.  (line    6)
* PROCEDURE:                             select.             (line  335)
* procedures, adding:                    adding-procedures.  (line   11)
* procedures, stored:                    stored-routines.    (line   13)
* process management (MySQL Cluster):    mysql-cluster-programs.
                                                             (line   30)
* process support:                       supported-os.       (line    6)
* processes, display:                    show-processlist.   (line    6)
* Processing events from schema table, thread state: mysql-cluster-thread-states.
                                                             (line   14)
* Processing events, thread state:       mysql-cluster-thread-states.
                                                             (line   10)
* processing, arguments:                 udf-arguments.      (line    6)
* PROCESSLIST:                           show-processlist.   (line    6)
* Processlist, thread command:           thread-commands.    (line   86)
* profiling session variable:            server-system-variables.
                                                             (line 3840)
* PROFILING, INFORMATION_SCHEMA table:   profiling-table.    (line    6)
* profiling_history_size session variable: server-system-variables.
                                                             (line 3849)
* program options (MySQL Cluster):       mysql-cluster-program-options-common.
                                                             (line    6)
* program variables, setting:            program-variables.  (line    6)
* program-development utilities:         programs-overview.  (line  268)
* programs, administrative:              programs-overview.  (line  167)
* programs, client <1>:                  building-clients.   (line   11)
* programs, client:                      programs-overview.  (line  132)
* programs, crash-me:                    portability.        (line    6)
* programs, stored <1>:                  stored-programs-views.
                                                             (line   15)
* programs, stored:                      sql-syntax-compound-statements.
                                                             (line   16)
* programs, utility:                     programs-overview.  (line  167)
* prompt command, mysql:                 mysql-commands.     (line  185)
* prompt option, mysql:                  mysql-command-options.
                                                             (line  378)
* prompts, meanings:                     entering-queries.   (line  134)
* pronunciation, MySQL:                  what-is-mysql.      (line   84)
* protocol option:                       connecting.         (line  152)
* protocol option, mysql:                mysql-command-options.
                                                             (line  384)
* protocol option, mysqladmin:           mysqladmin.         (line  346)
* protocol option, mysqlbinlog:          mysqlbinlog.        (line  277)
* protocol option, mysqlcheck:           mysqlcheck.         (line  297)
* protocol option, mysqldump:            mysqldump.          (line  753)
* protocol option, mysqlimport:          mysqlimport.        (line  225)
* protocol option, mysqlshow:            mysqlshow.          (line  162)
* protocol_version system variable:      server-system-variables.
                                                             (line 3858)
* pseudo_thread_id system variable:      server-system-variables.
                                                             (line 3871)
* PURGE BINARY LOGS:                     purge-binary-logs.  (line    6)
* PURGE MASTER LOGS:                     purge-binary-logs.  (line    6)
* PURGE STALE SESSIONS:                  mysql-cluster-start-phases.
                                                             (line   81)
* Purging old relay logs, thread state:  general-thread-states.
                                                             (line  202)
* Python API:                            apis-python.        (line    6)
* QUARTER():                             date-and-time-functions.
                                                             (line  771)
* queries, entering:                     entering-queries.   (line    6)
* queries, estimating performance:       estimating-performance.
                                                             (line    6)
* queries, examples:                     examples.           (line   18)
* queries, speed of:                     select-optimization.
                                                             (line   25)
* Query Cache:                           query-cache.        (line   13)
* query cache, thread states:            query-cache-thread-states.
                                                             (line    6)
* query end, thread state:               general-thread-states.
                                                             (line  206)
* query option, ndb_config:              mysql-cluster-programs-ndb-config.
                                                             (line   97)
* Query, thread command:                 thread-commands.    (line   90)
* query_alloc_block_size system variable: server-system-variables.
                                                             (line 3884)
* query_cache_limit system variable:     server-system-variables.
                                                             (line 3922)
* query_cache_min_res_unit system variable: server-system-variables.
                                                             (line 3953)
* query_cache_size system variable:      server-system-variables.
                                                             (line 3987)
* query_cache_type system variable:      server-system-variables.
                                                             (line 4027)
* query_cache_wlock_invalidate system variable: server-system-variables.
                                                             (line 4067)
* query_prealloc_size system variable:   server-system-variables.
                                                             (line 4093)
* questions:                             mysqladmin.         (line  169)
* questions, answering:                  mailing-list-use.   (line    6)
* Queueing master event to the relay log, thread state: slave-io-thread-states.
                                                             (line   57)
* quick option, myisamchk:               myisamchk-repair-options.
                                                             (line   72)
* quick option, mysql:                   mysql-command-options.
                                                             (line  391)
* quick option, mysqlcheck:              mysqlcheck.         (line  304)
* quick option, mysqldump:               mysqldump.          (line  760)
* quiet option, mysql_tableinfo:         mysql-tableinfo.    (line  121)
* quiet option, mysqlhotcopy:            mysqlhotcopy.       (line  152)
* QUIT command (MySQL Cluster):          mysql-cluster-mgm-client-commands.
                                                             (line  114)
* quit command, mysql:                   mysql-commands.     (line  194)
* Quit, thread command:                  thread-commands.    (line   94)
* quotation marks, in strings:           string-literals.    (line   93)
* QUOTE() <1>:                           mysql-real-escape-string.
                                                             (line   17)
* QUOTE() <2>:                           string-functions.   (line  522)
* QUOTE():                               string-literals.    (line  141)
* quote-names option, mysqldump:         mysqldump.          (line  767)
* quoting:                               string-literals.    (line  141)
* quoting binary data:                   string-literals.    (line  131)
* quoting of identifiers:                identifiers.        (line   18)
* quoting, column alias <1>:             problems-with-alias.
                                                             (line    6)
* quoting, column alias:                 identifiers.        (line   79)
* RADIANS():                             mathematical-functions.
                                                             (line  351)
* RAND():                                mathematical-functions.
                                                             (line  359)
* rand_seed1 session variable:           server-system-variables.
                                                             (line 4133)
* rand_seed2 session variable:           server-system-variables.
                                                             (line 4146)
* range join type, optimizer:            explain-output.     (line  301)
* range_alloc_block_size system variable: server-system-variables.
                                                             (line 4150)
* raw option, mysql:                     mysql-command-options.
                                                             (line  397)
* re-creating, grant tables:             mysql-install-db-problems.
                                                             (line  103)
* READ COMMITTED, transaction isolation level: set-transaction.
                                                             (line   69)
* READ UNCOMMITTED, transaction isolation level: set-transaction.
                                                             (line   61)
* read-from-remote-server option, mysqlbinlog: mysqlbinlog.  (line  284)
* read-only option, myisamchk:           myisamchk-check-options.
                                                             (line   55)
* read-only option, mysqld:              replication-options-slave.
                                                             (line  395)
* read_buffer_size myisamchk variable:   myisamchk-general-options.
                                                             (line   53)
* read_buffer_size system variable:      server-system-variables.
                                                             (line 4188)
* read_only system variable:             server-system-variables.
                                                             (line 4222)
* read_rnd_buffer_size system variable:  server-system-variables.
                                                             (line 4272)
* Reading event from the relay log, thread state: slave-sql-thread-states.
                                                             (line   13)
* Reading from net, thread state:        general-thread-states.
                                                             (line  211)
* Reading master dump table data, thread state: slave-connection-thread-states.
                                                             (line   29)
* REAL data type:                        numeric-type-overview.
                                                             (line  265)
* REAL_AS_FLOAT SQL mode:                server-sql-mode.    (line  308)
* Rebuilding the index on master dump table, thread state: slave-connection-thread-states.
                                                             (line   33)
* ReceiveBufferMemory:                   mysql-cluster-tcp-definition.
                                                             (line  157)
* reconfiguring:                         compilation-problems.
                                                             (line    6)
* reconnect option, mysql:               mysql-command-options.
                                                             (line  428)
* Reconnecting after a failed binlog dump request, thread state: slave-io-thread-states.
                                                             (line   45)
* Reconnecting after a failed master event read, thread state: slave-io-thread-states.
                                                             (line   70)
* reconnection, automatic:               auto-reconnect.     (line    6)
* record-level locks, InnoDB <1>:        innodb-next-key-locking.
                                                             (line    6)
* record-level locks, InnoDB <2>:        innodb-record-level-locks.
                                                             (line    6)
* record-level locks, InnoDB <3>:        innodb-transaction-model.
                                                             (line   65)
* record-level locks, InnoDB:            innodb-parameters.  (line  707)
* record_log_pos option, mysqlhotcopy:   mysqlhotcopy.       (line  156)
* recover option, myisamchk:             myisamchk-repair-options.
                                                             (line   79)
* RECOVER, XA transactions:              xa-statements.      (line    6)
* recovery, from crash:                  myisam-crash-recovery.
                                                             (line    6)
* recovery, incremental:                 point-in-time-recovery.
                                                             (line   11)
* recovery, point in time:               point-in-time-recovery.
                                                             (line   11)
* RedoBuffer:                            mysql-cluster-ndbd-definition.
                                                             (line 1784)
* reducing, data size:                   data-size.          (line    6)
* ref join type, optimizer:              explain-output.     (line  236)
* ref_or_null:                           is-null-optimization.
                                                             (line    6)
* ref_or_null join type, optimizer:      explain-output.     (line  262)
* references:                            alter-table.        (line  333)
* Refresh, thread command:               thread-commands.    (line   98)
* REGEXP:                                regexp.             (line   32)
* REGEXP operator:                       regexp.             (line    6)
* regexp option, mysql_find_rows:        mysql-find-rows.    (line   35)
* regexp option, mysqlhotcopy:           mysqlhotcopy.       (line  161)
* Register Slave, thread command:        thread-commands.    (line  103)
* Registering slave on master, thread state: slave-io-thread-states.
                                                             (line   25)
* regular expression syntax:             regexp.             (line    6)
* rehash command, mysql:                 mysql-commands.     (line  198)
* relational databases, defined:         what-is-mysql.      (line   39)
* relative option, mysqladmin:           mysqladmin.         (line  353)
* relay-log option, mysqld:              replication-options-slave.
                                                             (line  403)
* relay-log-index option, mysqld:        replication-options-slave.
                                                             (line  448)
* relay-log-info-file option, mysqld:    replication-options-slave.
                                                             (line  485)
* relay-log-purge option, mysqld:        replication-options-slave.
                                                             (line  505)
* relay-log-space-limit option, mysqld:  replication-options-slave.
                                                             (line  512)
* relay_log_index system variable:       replication-options-slave.
                                                             (line 1086)
* relay_log_info_file system variable:   replication-options-slave.
                                                             (line 1107)
* relay_log_purge system variable:       server-system-variables.
                                                             (line 4308)
* relay_log_space_limit system variable: server-system-variables.
                                                             (line 4328)
* release notes <1>:                     news-5-0-x.         (line  115)
* release notes:                         news.               (line   17)
* release notes, MySQL Community Server <1>: news-5-0-x.     (line  115)
* release notes, MySQL Community Server: news.               (line   17)
* release notes, MySQL Enterprise <1>:   news-5-0-x.         (line  115)
* release notes, MySQL Enterprise:       news.               (line   17)
* release numbers:                       which-version.      (line   19)
* RELEASE SAVEPOINT:                     savepoint.          (line    6)
* RELEASE_LOCK():                        miscellaneous-functions.
                                                             (line  182)
* releases, naming scheme:               choosing-version.   (line   57)
* releases, testing:                     choosing-version.   (line  119)
* releases, updating:                    many-versions.      (line    6)
* relnotes option, mysqlaccess:          mysqlaccess.        (line  126)
* remote administration (MySQL Cluster), and security issues: mysql-cluster-security-networking-issues.
                                                             (line  189)
* remove option, mysqld:                 server-options.     (line 1341)
* remove option, mysqlmanager:           instance-manager-command-options.
                                                             (line  150)
* Removing duplicates, thread state:     general-thread-states.
                                                             (line  215)
* removing tmp table, thread state:      general-thread-states.
                                                             (line  222)
* rename result table, thread state:     general-thread-states.
                                                             (line  232)
* RENAME TABLE:                          rename-table.       (line    6)
* RENAME USER:                           rename-user.        (line    6)
* rename, thread state:                  general-thread-states.
                                                             (line  228)
* renaming user accounts:                rename-user.        (line    6)
* Reopen tables, thread state:           general-thread-states.
                                                             (line  238)
* Repair by sorting, thread state:       general-thread-states.
                                                             (line  244)
* Repair done, thread state:             general-thread-states.
                                                             (line  248)
* repair option, mysqlcheck:             mysqlcheck.         (line  313)
* repair options, myisamchk:             myisamchk-repair-options.
                                                             (line    6)
* REPAIR TABLE:                          repair-table.       (line    6)
* REPAIR TABLE, and replication <1>:     replication-features-repair-table.
                                                             (line    6)
* REPAIR TABLE, and replication:         repair-table.       (line  122)
* Repair with keycache, thread state:    general-thread-states.
                                                             (line  253)
* repair, tables:                        mysqlcheck.         (line    6)
* repairing, tables:                     myisam-repair.      (line    6)
* REPEAT:                                repeat-statement.   (line    6)
* REPEAT():                              string-functions.   (line  541)
* REPEAT, labels:                        statement-labels.   (line    6)
* REPEATABLE READ, transaction isolation level: set-transaction.
                                                             (line   91)
* repertoire, character set:             charset-repertoire. (line    6)
* REPLACE:                               replace.            (line    6)
* replace:                               programs-overview.  (line  296)
* replace option, mysqlimport:           mysqlimport.        (line  232)
* replace utility:                       replace-utility.    (line    6)
* REPLACE():                             string-functions.   (line  550)
* replicas (MySQL Cluster):              mysql-cluster-nodes-groups.
                                                             (line    6)
* replicate-do-db option, mysqld:        replication-options-slave.
                                                             (line  533)
* replicate-do-table option, mysqld:     replication-options-slave.
                                                             (line  626)
* replicate-ignore-db option, mysqld:    replication-options-slave.
                                                             (line  583)
* replicate-ignore-table option, mysqld: replication-options-slave.
                                                             (line  648)
* replicate-rewrite-db option, mysqld:   replication-options-slave.
                                                             (line  671)
* replicate-same-server-id option, mysqld: replication-options-slave.
                                                             (line  700)
* replicate-wild-do-table option, mysqld: replication-options-slave.
                                                             (line  725)
* replicate-wild-ignore-table option, mysqld: replication-options-slave.
                                                             (line  772)
* replication:                           replication.        (line   13)
* replication filtering options, and case sensitivity: replication-rules.
                                                             (line   56)
* replication implementation:            replication-implementation.
                                                             (line   12)
* replication limitations:               replication-features.
                                                             (line   37)
* replication master, thread states:     master-thread-states.
                                                             (line    6)
* replication masters, statements:       replication-master-sql.
                                                             (line   12)
* replication options:                   replication-features.
                                                             (line   37)
* replication slave, thread states <1>:  slave-connection-thread-states.
                                                             (line    6)
* replication slave, thread states <2>:  slave-sql-thread-states.
                                                             (line    6)
* replication slave, thread states:      slave-io-thread-states.
                                                             (line    6)
* replication slaves, statements:        replication-slave-sql.
                                                             (line   17)
* replication, and AUTO_INCREMENT:       replication-features-auto-increment.
                                                             (line    6)
* replication, and character sets:       replication-features-charset.
                                                             (line    6)
* replication, and CREATE TABLE ... SELECT: replication-features-create-select.
                                                             (line    6)
* replication, and DATA DIRECTORY:       replication-features-directory.
                                                             (line    6)
* replication, and DROP ... IF EXISTS:   replication-features-drop-if-exists.
                                                             (line    6)
* replication, and errors on slave:      replication-features-slaveerrors.
                                                             (line    6)
* replication, and floating-point values: replication-features-floatvalues.
                                                             (line    6)
* replication, and FLUSH:                replication-features-flush.
                                                             (line    6)
* replication, and functions:            replication-features-functions.
                                                             (line    6)
* replication, and INDEX DIRECTORY:      replication-features-directory.
                                                             (line    6)
* replication, and LAST_INSERT_ID():     replication-features-auto-increment.
                                                             (line    6)
* replication, and LIMIT:                replication-features-limit.
                                                             (line    6)
* replication, and LOAD DATA:            replication-features-load.
                                                             (line    6)
* replication, and LOAD TABLE FROM MASTER: replication-features-load.
                                                             (line    6)
* replication, and MEMORY tables:        replication-features-memory.
                                                             (line    6)
* replication, and mysql (system) database: replication-features-mysqldb.
                                                             (line    6)
* replication, and partial updates:      replication-features-slaveerrors.
                                                             (line    6)
* replication, and privileges:           replication-features-userprivs.
                                                             (line    6)
* replication, and query optimizer:      replication-features-optimizer.
                                                             (line    6)
* replication, and REPAIR TABLE statement <1>: replication-features-repair-table.
                                                             (line    6)
* replication, and REPAIR TABLE statement: repair-table.     (line  122)
* replication, and reserved words:       replication-features-reserved-words.
                                                             (line    6)
* replication, and slow query log:       replication-features-logging.
                                                             (line    6)
* replication, and SQL mode:             replication-features-sql-mode.
                                                             (line    6)
* replication, and temporary tables:     replication-features-temptables.
                                                             (line    6)
* replication, and time zones:           replication-features-timezone.
                                                             (line    6)
* replication, and TIMESTAMP <1>:        replication-features-timestamp.
                                                             (line    6)
* replication, and TIMESTAMP <2>:        replication-features-auto-increment.
                                                             (line    6)
* replication, and TIMESTAMP:            upgrading-from-previous-series.
                                                             (line  329)
* replication, and transactions <1>:     replication-features-transactions.
                                                             (line    6)
* replication, and transactions:         replication-features-timeout.
                                                             (line    6)
* replication, and triggers:             replication-features-triggers.
                                                             (line    6)
* replication, and variables:            replication-features-variables.
                                                             (line    6)
* replication, and views:                replication-features-views.
                                                             (line    6)
* replication, between MySQL server versions <1>: replication-features-timestamp.
                                                             (line    6)
* replication, between MySQL server versions: upgrading-from-previous-series.
                                                             (line  329)
* replication, crashes:                  replication-features-shutdowns.
                                                             (line    6)
* replication, shutdown and restart <1>: replication-features-temptables.
                                                             (line    6)
* replication, shutdown and restart:     replication-features-shutdowns.
                                                             (line    6)
* replication, timeouts:                 replication-features-timeout.
                                                             (line    6)
* report-host option, mysqld:            replication-options-slave.
                                                             (line  798)
* report-password option, mysqld:        replication-options-slave.
                                                             (line  825)
* report-port option, mysqld:            replication-options-slave.
                                                             (line  852)
* report-user option, mysqld:            replication-options-slave.
                                                             (line  876)
* reporting, bugs:                       bug-reports.        (line    6)
* reporting, Connector/Net problems:     connector-net-support.
                                                             (line   12)
* reporting, Connector/ODBC problems:    connector-odbc-support.
                                                             (line   14)
* reporting, errors <1>:                 bug-reports.        (line    6)
* reporting, errors:                     introduction.       (line   76)
* Requesting binlog dump, thread state:  slave-io-thread-states.
                                                             (line   30)
* REQUIRE GRANT option:                  grant.              (line  488)
* reschedule, thread state:              delayed-insert-thread-states.
                                                             (line   78)
* reserved words:                        reserved-words.     (line    6)
* reserved words, and replication:       replication-features-reserved-words.
                                                             (line    6)
* RESET MASTER:                          reset-master.       (line    6)
* RESET SLAVE:                           reset-slave.        (line    6)
* Reset stmt, thread command:            thread-commands.    (line  107)
* resetmaster option, mysqlhotcopy:      mysqlhotcopy.       (line  166)
* resetslave option, mysqlhotcopy:       mysqlhotcopy.       (line  170)
* resolve_stack_dump <1>:                resolve-stack-dump. (line    6)
* resolve_stack_dump:                    programs-overview.  (line  284)
* resolve_stack_dump, help option:       resolve-stack-dump. (line   21)
* resolve_stack_dump, numeric-dump-file option: resolve-stack-dump.
                                                             (line   25)
* resolve_stack_dump, symbols-file option: resolve-stack-dump.
                                                             (line   29)
* resolve_stack_dump, version option:    resolve-stack-dump. (line   33)
* resolveip <1>:                         resolveip.          (line    6)
* resolveip:                             programs-overview.  (line  301)
* resolveip, help option:                resolveip.          (line   15)
* resolveip, silent option:              resolveip.          (line   19)
* resolveip, version option:             resolveip.          (line   23)
* resource limits, user accounts <1>:    grant.              (line  456)
* resource limits, user accounts <2>:    user-resources.     (line    6)
* resource limits, user accounts:        server-system-variables.
                                                             (line 3145)
* RESTART command (MySQL Cluster):       mysql-cluster-mgm-client-commands.
                                                             (line   68)
* restarting, the server:                unix-postinstallation.
                                                             (line  264)
* RestartOnErrorInsert:                  mysql-cluster-ndbd-definition.
                                                             (line 1241)
* RESTORE TABLE:                         restore-table.      (line    6)
* restoring backups, in MySQL Cluster:   mysql-cluster-programs-ndb-restore.
                                                             (line    6)
* restrictions, character sets:          charset-restrictions.
                                                             (line    6)
* restrictions, server-side cursors:     cursor-restrictions.
                                                             (line    6)
* restrictions, stored routines:         stored-program-restrictions.
                                                             (line    6)
* restrictions, subqueries:              subquery-restrictions.
                                                             (line    6)
* restrictions, triggers:                stored-program-restrictions.
                                                             (line    6)
* restrictions, views:                   view-restrictions.  (line    6)
* restrictions, XA transactions:         xa-restrictions.    (line    6)
* result-file option, mysqlbinlog:       mysqlbinlog.        (line  295)
* result-file option, mysqldump:         mysqldump.          (line  776)
* retrieving, data from tables:          retrieving-data.    (line   18)
* RETURN:                                return.             (line    6)
* return (\r) <1>:                       load-data.          (line  417)
* return (\r):                           string-literals.    (line   73)
* return values, UDFs:                   udf-return-values.  (line    6)
* REVERSE():                             string-functions.   (line  561)
* REVOKE:                                revoke.             (line    6)
* revoking, privileges:                  revoke.             (line    6)
* rhost option, mysqlaccess:             mysqlaccess.        (line  130)
* RIGHT JOIN:                            join.               (line    6)
* RIGHT OUTER JOIN:                      join.               (line    6)
* RIGHT():                               string-functions.   (line  570)
* RLIKE:                                 regexp.             (line   32)
* ROLLBACK <1>:                          commit.             (line    6)
* ROLLBACK:                              ansi-diff-transactions.
                                                             (line    6)
* rollback option, mysqlaccess:          mysqlaccess.        (line  134)
* ROLLBACK TO SAVEPOINT:                 savepoint.          (line    6)
* ROLLBACK, XA transactions:             xa-statements.      (line    6)
* Rolling back, thread state:            general-thread-states.
                                                             (line  258)
* rolling restart (MySQL Cluster):       mysql-cluster-rolling-restart.
                                                             (line    6)
* ROLLUP:                                group-by-modifiers. (line    6)
* root password:                         default-privileges. (line    6)
* root user, password resetting:         resetting-permissions.
                                                             (line   12)
* ROUND():                               mathematical-functions.
                                                             (line  444)
* rounding:                              precision-math.     (line   14)
* rounding errors:                       numeric-type-overview.
                                                             (line  142)
* routines option, mysqldump:            mysqldump.          (line  784)
* ROUTINES, INFORMATION_SCHEMA table:    routines-table.     (line    6)
* ROW:                                   row-subqueries.     (line    6)
* row subqueries:                        row-subqueries.     (line    6)
* row-level locking:                     internal-locking.   (line    6)
* ROW_COUNT():                           information-functions.
                                                             (line  451)
* rowid option, ndb_select_all:          mysql-cluster-programs-ndb-select-all.
                                                             (line   56)
* rows option, mysql_find_rows:          mysql-find-rows.    (line   39)
* rows option, ndb_config:               mysql-cluster-programs-ndb-config.
                                                             (line  224)
* rows, counting:                        counting-rows.      (line    6)
* rows, deleting:                        deleting-from-related-tables.
                                                             (line    6)
* rows, locking:                         ansi-diff-transactions.
                                                             (line  168)
* rows, matching problems:               no-matching-rows.   (line    6)
* rows, selecting:                       selecting-rows.     (line    6)
* rows, sorting:                         sorting-rows.       (line    6)
* RPAD():                                string-functions.   (line  580)
* RPM file:                              linux-installation-rpm.
                                                             (line    6)
* rpm option, mysql_install_db:          mysql-install-db.   (line   59)
* RPM Package Manager:                   linux-installation-rpm.
                                                             (line    6)
* RTRIM():                               string-functions.   (line  593)
* Ruby API:                              apis-ruby.          (line   11)
* run-as-service option, mysqlmanager:   instance-manager-command-options.
                                                             (line  156)
* running configure after prior invocation: compilation-problems.
                                                             (line   14)
* running, ANSI mode:                    ansi-mode.          (line    6)
* running, batch mode:                   batch-mode.         (line    6)
* running, multiple servers:             multiple-servers.   (line   13)
* running, queries:                      entering-queries.   (line    6)
* safe-mode option, mysqld:              server-options.     (line 1351)
* safe-recover option, myisamchk:        myisamchk-repair-options.
                                                             (line   92)
* safe-show-database option, mysqld:     server-options.     (line 1362)
* safe-updates option:                   safe-updates.       (line    6)
* safe-updates option, mysql:            mysql-command-options.
                                                             (line  435)
* safe-user-create option, mysqld <1>:   privileges-options. (line   63)
* safe-user-create option, mysqld:       server-options.     (line 1383)
* safe_mysqld:                           mysqld-safe.        (line    6)
* Sakila:                                history.            (line    6)
* SAVEPOINT:                             savepoint.          (line    6)
* Saving state, thread state:            general-thread-states.
                                                             (line  262)
* scale, arithmetic:                     precision-math.     (line   14)
* scale, numeric:                        data-types.         (line   37)
* SCHEMA():                              information-functions.
                                                             (line  508)
* schema, altering:                      alter-database.     (line    6)
* schema, creating:                      create-database.    (line    6)
* schema, deleting:                      drop-database.      (line    6)
* SCHEMA_PRIVILEGES, INFORMATION_SCHEMA table: schema-privileges-table.
                                                             (line    6)
* SCHEMATA, INFORMATION_SCHEMA table:    schemata-table.     (line    6)
* SCI (Scalable Coherent Interface) <1>: mysql-cluster-sci-sockets.
                                                             (line    6)
* SCI (Scalable Coherent Interface):     mysql-cluster-sci-definition.
                                                             (line    6)
* script files:                          batch-mode.         (line    6)
* scripts <1>:                           mysqld-multi.       (line    6)
* scripts:                               mysqld-safe.        (line    6)
* scripts, mysql_install_db:             mysql-install-db-problems.
                                                             (line    6)
* scripts, SQL:                          mysql.              (line   15)
* Searching rows for update, thread state: general-thread-states.
                                                             (line  269)
* searching, and case sensitivity:       case-sensitivity.   (line    6)
* searching, full-text:                  fulltext-search.    (line   16)
* searching, MySQL Web pages:            bug-reports.        (line    6)
* searching, two keys:                   searching-on-two-keys.
                                                             (line    6)
* SEC_TO_TIME():                         date-and-time-functions.
                                                             (line  785)
* SECOND():                              date-and-time-functions.
                                                             (line  778)
* secondary index, InnoDB:               innodb-index-types. (line    6)
* secure-auth option, mysql:             mysql-command-options.
                                                             (line  443)
* secure-auth option, mysqld <1>:        privileges-options. (line   78)
* secure-auth option, mysqld:            server-options.     (line 1408)
* secure-file-priv option, mysqld <1>:   privileges-options. (line   87)
* secure-file-priv option, mysqld:       server-options.     (line 1428)
* secure_auth system variable:           server-system-variables.
                                                             (line 4358)
* secure_file_priv system variable:      server-system-variables.
                                                             (line 4387)
* securing a MySQL Cluster:              mysql-cluster-security-mysql-security-procedures.
                                                             (line    6)
* security system:                       privilege-system.   (line   16)
* security, against attackers:           security-against-attack.
                                                             (line    6)
* security, and malicious SQL statements: mysql-cluster-security-mysql-privileges.
                                                             (line   80)
* security, and NDB utilities:           mysql-cluster-security-mysql-security-procedures.
                                                             (line   75)
* SELECT INTO TABLE:                     ansi-diff-select-into-table.
                                                             (line    6)
* SELECT speed:                          select-speed.       (line    6)
* SELECT, INTO:                          select-into.        (line    6)
* SELECT, LIMIT:                         select.             (line   13)
* SELECT, optimizing <1>:                explain.            (line    6)
* SELECT, optimizing:                    using-explain.      (line    6)
* SELECT, Query Cache:                   query-cache.        (line   13)
* select_limit variable:                 mysql-command-options.
                                                             (line  600)
* selecting, databases:                  creating-database.  (line    6)
* SendBufferMemory:                      mysql-cluster-tcp-definition.
                                                             (line   91)
* Sending binlog event to slave, thread state: master-thread-states.
                                                             (line   11)
* sending cached result to client, thread state: query-cache-thread-states.
                                                             (line   24)
* SendLimit:                             mysql-cluster-sci-definition.
                                                             (line  161)
* SendSignalId <1>:                      mysql-cluster-sci-definition.
                                                             (line  179)
* SendSignalId <2>:                      mysql-cluster-shm-definition.
                                                             (line  113)
* SendSignalId:                          mysql-cluster-tcp-definition.
                                                             (line  113)
* SEQUENCE:                              example-auto-increment.
                                                             (line    6)
* sequence emulation:                    information-functions.
                                                             (line  414)
* sequences:                             example-auto-increment.
                                                             (line    6)
* SERIAL:                                numeric-type-overview.
                                                             (line    6)
* SERIAL DEFAULT VALUE:                  data-type-defaults. (line   90)
* SERIALIZABLE, transaction isolation level: set-transaction.
                                                             (line  113)
* server administration:                 mysqladmin.         (line    6)
* server variables <1>:                  show-variables.     (line    6)
* server variables:                      server-system-variables.
                                                             (line    6)
* server, connecting <1>:                connecting.         (line    6)
* server, connecting:                    connecting-disconnecting.
                                                             (line    6)
* server, debugging:                     debugging-server.   (line   16)
* server, disconnecting:                 connecting-disconnecting.
                                                             (line    6)
* server, logs:                          server-logs.        (line   14)
* server, restart:                       unix-postinstallation.
                                                             (line  264)
* server, shutdown:                      unix-postinstallation.
                                                             (line  256)
* server, signal handling:               server-signal-response.
                                                             (line    6)
* server, starting:                      unix-postinstallation.
                                                             (line   49)
* server, starting and stopping:         automatic-start.    (line    6)
* server, starting problems:             starting-server.    (line    6)
* server-id option, mysqld:              replication-options.
                                                             (line   21)
* server-side cursor, restrictions:      cursor-restrictions.
                                                             (line    6)
* server_id system variable:             server-system-variables.
                                                             (line 4412)
* ServerPort:                            mysql-cluster-ndbd-definition.
                                                             (line  109)
* servers, multiple:                     multiple-servers.   (line   13)
* service-startup-timeout option, mysql.server: mysql-server.
                                                             (line   49)
* session variable, autocommit:          server-system-variables.
                                                             (line  502)
* session variable, big_tables:          server-system-variables.
                                                             (line  779)
* session variable, error_count:         server-system-variables.
                                                             (line 1521)
* session variable, foreign_key_checks:  server-system-variables.
                                                             (line 1606)
* session variable, identity:            server-system-variables.
                                                             (line 1916)
* session variable, insert_id:           server-system-variables.
                                                             (line 1996)
* session variable, last_insert_id:      server-system-variables.
                                                             (line 2330)
* session variable, profiling:           server-system-variables.
                                                             (line 3840)
* session variable, profiling_history_size: server-system-variables.
                                                             (line 3849)
* session variable, rand_seed1:          server-system-variables.
                                                             (line 4133)
* session variable, rand_seed2:          server-system-variables.
                                                             (line 4146)
* session variable, sql_auto_is_null:    server-system-variables.
                                                             (line 4585)
* session variable, sql_big_selects:     server-system-variables.
                                                             (line 4612)
* session variable, sql_buffer_result:   server-system-variables.
                                                             (line 4635)
* session variable, sql_log_bin:         server-system-variables.
                                                             (line 4653)
* session variable, sql_log_off:         server-system-variables.
                                                             (line 4668)
* session variable, sql_log_update:      server-system-variables.
                                                             (line 4684)
* session variable, sql_notes:           server-system-variables.
                                                             (line 4745)
* session variable, sql_quote_show_create: server-system-variables.
                                                             (line 4755)
* session variable, sql_safe_updates:    server-system-variables.
                                                             (line 4764)
* session variable, sql_warnings:        server-system-variables.
                                                             (line 4803)
* session variable, timestamp:           server-system-variables.
                                                             (line 5198)
* session variable, unique_checks:       server-system-variables.
                                                             (line 5405)
* session variable, warning_count:       server-system-variables.
                                                             (line 5580)
* session variables, and replication:    replication-features-variables.
                                                             (line    6)
* SESSION_USER():                        information-functions.
                                                             (line  513)
* SET:                                   set-option.         (line    6)
* SET data type <1>:                     set.                (line    6)
* SET data type:                         string-type-overview.
                                                             (line  288)
* SET GLOBAL sql_slave_skip_counter:     set-global-sql-slave-skip-counter.
                                                             (line    6)
* SET OPTION:                            set-option.         (line    6)
* Set option, thread command:            thread-commands.    (line  111)
* SET PASSWORD:                          set-password.       (line    6)
* SET PASSWORD statement:                assigning-passwords.
                                                             (line    6)
* SET sql_log_bin:                       set-sql-log-bin.    (line    6)
* SET statement, assignment operator:    assignment-operators.
                                                             (line   70)
* SET TRANSACTION:                       set-transaction.    (line    6)
* SET, CHARACTER SET <1>:                set-option.         (line  167)
* SET, CHARACTER SET:                    charset-connection. (line    6)
* SET, NAMES <1>:                        set-option.         (line  183)
* SET, NAMES <2>:                        charset-applications.
                                                             (line    6)
* SET, NAMES:                            charset-connection. (line    6)
* SET, ONE_SHOT:                         set-option.         (line  199)
* SET, size:                             storage-requirements.
                                                             (line  258)
* set-auto-increment[ option, myisamchk: myisamchk-other-options.
                                                             (line   28)
* set-character-set option, myisamchk:   myisamchk-repair-options.
                                                             (line  105)
* set-charset option, mysqlbinlog:       mysqlbinlog.        (line  299)
* set-charset option, mysqldump:         mysqldump.          (line  811)
* set-collation option, myisamchk:       myisamchk-repair-options.
                                                             (line  110)
* setting passwords:                     set-password.       (line    6)
* setting program variables:             program-variables.  (line    6)
* setting, passwords:                    assigning-passwords.
                                                             (line    6)
* setup, postinstallation:               postinstallation.   (line   11)
* setup, thread state:                   general-thread-states.
                                                             (line  283)
* SHA():                                 encryption-functions.
                                                             (line  330)
* SHA1():                                encryption-functions.
                                                             (line  330)
* shared memory transporter:             mysql-cluster-shm-definition.
                                                             (line    6)
* shared-memory option, mysqld:          server-options.     (line 1452)
* shared-memory-base-name option:        connecting.         (line  182)
* shared-memory-base-name option, mysqld: server-options.    (line 1457)
* shared_memory system variable:         server-system-variables.
                                                             (line 4437)
* shared_memory_base_name system variable: server-system-variables.
                                                             (line 4448)
* SharedBufferSize:                      mysql-cluster-sci-definition.
                                                             (line  141)
* shell syntax:                          manual-conventions. (line  120)
* ShmKey:                                mysql-cluster-shm-definition.
                                                             (line   80)
* ShmSize:                               mysql-cluster-shm-definition.
                                                             (line   96)
* short-form option, mysqlbinlog:        mysqlbinlog.        (line  305)
* SHOW BINARY LOGS <1>:                  show-binary-logs.   (line    6)
* SHOW BINARY LOGS:                      show.               (line   46)
* SHOW BINLOG EVENTS <1>:                show-binlog-events. (line    6)
* SHOW BINLOG EVENTS:                    show.               (line   46)
* SHOW CHARACTER SET <1>:                show-character-set. (line    6)
* SHOW CHARACTER SET:                    show.               (line   46)
* SHOW COLLATION <1>:                    show-collation.     (line    6)
* SHOW COLLATION:                        show.               (line   46)
* SHOW COLUMNS <1>:                      show-columns.       (line    6)
* SHOW COLUMNS:                          show.               (line   46)
* SHOW command (MySQL Cluster):          mysql-cluster-mgm-client-commands.
                                                             (line   24)
* SHOW CREATE DATABASE <1>:              show-create-database.
                                                             (line    6)
* SHOW CREATE DATABASE:                  show.               (line   46)
* SHOW CREATE FUNCTION <1>:              show-create-function.
                                                             (line    6)
* SHOW CREATE FUNCTION:                  show.               (line   46)
* SHOW CREATE PROCEDURE <1>:             show-create-procedure.
                                                             (line    6)
* SHOW CREATE PROCEDURE:                 show.               (line   46)
* SHOW CREATE SCHEMA <1>:                show-create-database.
                                                             (line    6)
* SHOW CREATE SCHEMA:                    show.               (line   46)
* SHOW CREATE TABLE <1>:                 show-create-table.  (line    6)
* SHOW CREATE TABLE:                     show.               (line   46)
* SHOW CREATE VIEW <1>:                  show-create-view.   (line    6)
* SHOW CREATE VIEW:                      show.               (line   46)
* SHOW DATABASES <1>:                    show-databases.     (line    6)
* SHOW DATABASES:                        show.               (line   46)
* SHOW ENGINE <1>:                       show-engine.        (line    6)
* SHOW ENGINE:                           show.               (line   46)
* SHOW ENGINE BDB LOGS:                  show-engine.        (line    6)
* SHOW ENGINE INNODB STATUS:             show-engine.        (line    6)
* SHOW ENGINE NDB STATUS <1>:            mysql-cluster-sql-statements.
                                                             (line   10)
* SHOW ENGINE NDB STATUS:                show-engine.        (line    6)
* SHOW ENGINE NDBCLUSTER STATUS:         mysql-cluster-sql-statements.
                                                             (line   10)
* SHOW ENGINE, used with MySQL Cluster:  mysql-cluster-sql-statements.
                                                             (line   10)
* SHOW ENGINES <1>:                      show-engines.       (line    6)
* SHOW ENGINES:                          show.               (line   46)
* SHOW ENGINES, used with MySQL Cluster: mysql-cluster-sql-statements.
                                                             (line   20)
* SHOW ERRORS <1>:                       show-errors.        (line    6)
* SHOW ERRORS:                           show.               (line   46)
* SHOW ERRORS, and MySQL Cluster:        faqs-mysql-cluster. (line    6)
* SHOW extensions:                       extended-show.      (line    6)
* SHOW FIELDS <1>:                       show-columns.       (line  104)
* SHOW FIELDS:                           show.               (line   46)
* SHOW FUNCTION CODE <1>:                show-function-code. (line    6)
* SHOW FUNCTION CODE:                    show.               (line   46)
* SHOW FUNCTION STATUS <1>:              show-function-status.
                                                             (line    6)
* SHOW FUNCTION STATUS:                  show.               (line   46)
* SHOW GRANTS <1>:                       show-grants.        (line    6)
* SHOW GRANTS:                           show.               (line   46)
* SHOW INDEX <1>:                        show-index.         (line    6)
* SHOW INDEX:                            show.               (line   46)
* SHOW INNODB STATUS:                    show.               (line   46)
* SHOW KEYS <1>:                         show-index.         (line    6)
* SHOW KEYS:                             show.               (line   46)
* SHOW LOGS:                             show.               (line   46)
* SHOW MASTER LOGS <1>:                  show-binary-logs.   (line    6)
* SHOW MASTER LOGS:                      show.               (line   46)
* SHOW MASTER STATUS <1>:                show-master-status. (line    6)
* SHOW MASTER STATUS:                    show.               (line   46)
* SHOW MUTEX STATUS:                     show.               (line   46)
* SHOW OPEN TABLES <1>:                  show-open-tables.   (line    6)
* SHOW OPEN TABLES:                      show.               (line   46)
* SHOW PRIVILEGES <1>:                   show-privileges.    (line    6)
* SHOW PRIVILEGES:                       show.               (line   46)
* SHOW PROCEDURE CODE <1>:               show-procedure-code.
                                                             (line    6)
* SHOW PROCEDURE CODE:                   show.               (line   46)
* SHOW PROCEDURE STATUS <1>:             show-procedure-status.
                                                             (line    6)
* SHOW PROCEDURE STATUS:                 show.               (line   46)
* SHOW PROCESSLIST <1>:                  show-processlist.   (line    6)
* SHOW PROCESSLIST:                      show.               (line   46)
* SHOW PROFILE <1>:                      show-profiles.      (line    6)
* SHOW PROFILE <2>:                      show-profile.       (line    6)
* SHOW PROFILE:                          show.               (line   46)
* SHOW PROFILES <1>:                     show-profiles.      (line    6)
* SHOW PROFILES:                         show.               (line   46)
* SHOW SCHEMAS <1>:                      show-databases.     (line    6)
* SHOW SCHEMAS:                          show.               (line   46)
* SHOW SLAVE HOSTS <1>:                  show-slave-hosts.   (line    6)
* SHOW SLAVE HOSTS:                      show.               (line   46)
* SHOW SLAVE STATUS <1>:                 show-slave-status.  (line    6)
* SHOW SLAVE STATUS:                     show.               (line   46)
* SHOW STATUS:                           show.               (line   46)
* SHOW STATUS, used with MySQL Cluster:  mysql-cluster-sql-statements.
                                                             (line   54)
* SHOW STORAGE ENGINES:                  show-engines.       (line    6)
* SHOW TABLE STATUS:                     show.               (line   46)
* SHOW TABLE TYPES:                      show-engines.       (line    6)
* SHOW TABLES <1>:                       show-tables.        (line    6)
* SHOW TABLES:                           show.               (line   46)
* SHOW TRIGGERS <1>:                     show-triggers.      (line    6)
* SHOW TRIGGERS:                         show.               (line   46)
* SHOW VARIABLES:                        show.               (line   46)
* SHOW VARIABLES, used with MySQL Cluster: mysql-cluster-sql-statements.
                                                             (line   28)
* SHOW WARNINGS <1>:                     show-warnings.      (line    6)
* SHOW WARNINGS:                         show.               (line   46)
* SHOW WARNINGS, and MySQL Cluster:      faqs-mysql-cluster. (line    6)
* SHOW with WHERE <1>:                   extended-show.      (line    6)
* SHOW with WHERE:                       information-schema. (line   28)
* SHOW, in MySQL Cluster management client: mysql-cluster-quick.
                                                             (line  145)
* show-slave-auth-info option, mysqld:   replication-options-slave.
                                                             (line  903)
* show-table-type option, mysqlshow:     mysqlshow.          (line  169)
* show-temp-status option, ndb_show_tables: mysql-cluster-programs-ndb-show-tables.
                                                             (line   51)
* show-warnings option, mysql:           mysql-command-options.
                                                             (line  449)
* showing, database information:         mysqlshow.          (line    6)
* SHUTDOWN command (MySQL Cluster):      mysql-cluster-mgm-client-commands.
                                                             (line  120)
* Shutdown, thread command:              thread-commands.    (line  116)
* shutdown_timeout variable:             mysqladmin.         (line  412)
* shutting down, the server:             unix-postinstallation.
                                                             (line  256)
* Shutting down, thread state:           mysql-cluster-thread-states.
                                                             (line   18)
* sigint-ignore option, mysql:           mysql-command-options.
                                                             (line  455)
* SIGN():                                mathematical-functions.
                                                             (line  511)
* signals, server response:              server-signal-response.
                                                             (line    6)
* SigNum:                                mysql-cluster-shm-definition.
                                                             (line  149)
* silent column changes:                 silent-column-changes.
                                                             (line    6)
* silent option, make_win_src_distribution: make-win-src-distribution.
                                                             (line   32)
* silent option, myisamchk:              myisamchk-general-options.
                                                             (line   27)
* silent option, myisampack:             myisampack.         (line   93)
* silent option, mysql:                  mysql-command-options.
                                                             (line  459)
* silent option, mysqladmin:             mysqladmin.         (line  359)
* silent option, mysqlcheck:             mysqlcheck.         (line  318)
* silent option, mysqld_multi:           mysqld-multi.       (line  155)
* silent option, mysqlimport:            mysqlimport.        (line  242)
* silent option, perror:                 perror.             (line   48)
* silent option, resolveip:              resolveip.          (line   19)
* SIN():                                 mathematical-functions.
                                                             (line  523)
* single quote (\'):                     string-literals.    (line   69)
* single user mode (MySQL Cluster) <1>:  mysql-cluster-single-user-mode.
                                                             (line    6)
* single user mode (MySQL Cluster):      mysql-cluster-mgm-client-commands.
                                                             (line   91)
* single user mode (MySQL Cluster), and ndb_restore: mysql-cluster-programs-ndb-restore.
                                                             (line   19)
* single-transaction option, mysqldump:  mysqldump.          (line  817)
* single-user option, ndb_waiter:        mysql-cluster-programs-ndb-waiter.
                                                             (line   75)
* size of tables:                        table-size-limit.   (line    6)
* sizes, display:                        data-types.         (line   31)
* skip-bdb option, mysqld <1>:           bdb-start.          (line   72)
* skip-bdb option, mysqld:               server-options.     (line 1463)
* skip-column-names option, mysql:       mysql-command-options.
                                                             (line  468)
* skip-comments option, mysqldump:       mysqldump.          (line  856)
* skip-concurrent-insert option, mysqld: server-options.     (line 1469)
* skip-external-locking option, mysqld:  server-options.     (line 1475)
* skip-grant-tables option, mysqld <1>:  privileges-options. (line   96)
* skip-grant-tables option, mysqld:      server-options.     (line 1484)
* skip-host-cache option, mysqld:        server-options.     (line 1500)
* skip-innodb option, mysqld <1>:        innodb-parameters.  (line  134)
* skip-innodb option, mysqld:            server-options.     (line 1506)
* skip-kill-mysqld option, mysqld_safe:  mysqld-safe.        (line  228)
* skip-line-numbers option, mysql:       mysql-command-options.
                                                             (line  472)
* skip-merge option, mysqld:             server-options.     (line 1513)
* skip-name-resolve option, mysql_install_db: mysql-install-db.
                                                             (line   64)
* skip-name-resolve option, mysqld <1>:  privileges-options. (line  107)
* skip-name-resolve option, mysqld:      server-options.     (line 1522)
* skip-ndbcluster option, mysqld:        mysql-cluster-program-options-mysqld.
                                                             (line  119)
* skip-networking option, mysqld <1>:    privileges-options. (line  112)
* skip-networking option, mysqld:        server-options.     (line 1529)
* skip-opt option, mysqldump:            mysqldump.          (line  860)
* skip-safemalloc option, mysqld:        server-options.     (line 1576)
* skip-show-database option, mysqld <1>: privileges-options. (line  117)
* skip-show-database option, mysqld:     server-options.     (line 1589)
* skip-slave-start option, mysqld:       replication-options-slave.
                                                             (line  920)
* skip-stack-trace option, mysqld:       server-options.     (line 1610)
* skip-symbolic-links option, mysqld:    server-options.     (line 1553)
* skip-thread-priority option, mysqld:   server-options.     (line 1623)
* skip-use-db option, mysql_find_rows:   mysql-find-rows.    (line   43)
* skip_external_locking system variable: server-system-variables.
                                                             (line 4461)
* skip_networking system variable:       server-system-variables.
                                                             (line 4467)
* skip_show_database system variable:    server-system-variables.
                                                             (line 4476)
* slave-load-tmpdir option, mysqld:      replication-options-slave.
                                                             (line  957)
* slave-net-timeout option, mysqld:      replication-options-slave.
                                                             (line  979)
* slave-skip-errors option, mysqld:      replication-options-slave.
                                                             (line 1006)
* slave_compressed_protocol option, mysqld: replication-options-slave.
                                                             (line  936)
* slave_compressed_protocol system variable: replication-options-slave.
                                                             (line 1132)
* slave_load_tmpdir system variable:     replication-options-slave.
                                                             (line 1152)
* slave_net_timeout system variable:     replication-options-slave.
                                                             (line 1173)
* slave_skip_errors system variable:     replication-options-slave.
                                                             (line 1196)
* slave_transaction_retries system variable: replication-options-slave.
                                                             (line 1214)
* sleep option, mysqladmin:              mysqladmin.         (line  363)
* SLEEP():                               miscellaneous-functions.
                                                             (line  194)
* Sleep, thread command:                 thread-commands.    (line  120)
* slow queries:                          mysqladmin.         (line  174)
* slow query log:                        slow-query-log.     (line    6)
* slow query log, and replication:       replication-features-logging.
                                                             (line    6)
* slow_launch_time system variable:      server-system-variables.
                                                             (line 4491)
* SMALLINT data type:                    numeric-type-overview.
                                                             (line  111)
* socket location, changing:             source-configuration-options.
                                                             (line  330)
* socket option:                         connecting.         (line  191)
* socket option, mysql:                  mysql-command-options.
                                                             (line  477)
* socket option, mysql_config:           mysql-config.       (line   43)
* socket option, mysql_convert_table_format: mysql-convert-table-format.
                                                             (line   50)
* socket option, mysql_explain_log:      mysql-explain-log.  (line   48)
* socket option, mysql_setpermission:    mysql-setpermission.
                                                             (line   51)
* socket option, mysql_tableinfo:        mysql-tableinfo.    (line  125)
* socket option, mysqladmin:             mysqladmin.         (line  370)
* socket option, mysqlbinlog:            mysqlbinlog.        (line  311)
* socket option, mysqlcheck:             mysqlcheck.         (line  322)
* socket option, mysqld:                 server-options.     (line 1640)
* socket option, mysqld_safe:            mysqld-safe.        (line  233)
* socket option, mysqldump:              mysqldump.          (line  864)
* socket option, mysqlhotcopy:           mysqlhotcopy.       (line  174)
* socket option, mysqlimport:            mysqlimport.        (line  246)
* socket option, mysqlmanager:           instance-manager-command-options.
                                                             (line  162)
* socket option, mysqlshow:              mysqlshow.          (line  175)
* socket system variable:                server-system-variables.
                                                             (line 4511)
* Solaris installation problems:         solaris.            (line   11)
* Solaris troubleshooting:               compilation-problems.
                                                             (line  136)
* Solaris x86_64 issues:                 innodb-tuning.      (line    6)
* Solaris, installation:                 solaris-installation.
                                                             (line    6)
* SOME:                                  any-in-some-subqueries.
                                                             (line    6)
* sort-index option, myisamchk:          myisamchk-other-options.
                                                             (line   36)
* sort-records option, myisamchk:        myisamchk-other-options.
                                                             (line   41)
* sort-recover option, myisamchk:        myisamchk-repair-options.
                                                             (line  116)
* sort_buffer_size myisamchk variable:   myisamchk-general-options.
                                                             (line   53)
* sort_buffer_size system variable:      server-system-variables.
                                                             (line 4538)
* sort_key_blocks myisamchk variable:    myisamchk-general-options.
                                                             (line   53)
* Sorting for group, thread state:       general-thread-states.
                                                             (line  288)
* Sorting for order, thread state:       general-thread-states.
                                                             (line  292)
* Sorting index, thread state:           general-thread-states.
                                                             (line  296)
* Sorting result, thread state:          general-thread-states.
                                                             (line  301)
* sorting, data:                         sorting-rows.       (line    6)
* sorting, grant tables <1>:             request-access.     (line   51)
* sorting, grant tables:                 connection-access.  (line  123)
* sorting, table rows:                   sorting-rows.       (line    6)
* SOUNDEX():                             string-functions.   (line  602)
* SOUNDS LIKE:                           string-functions.   (line  641)
* source (mysql client command) <1>:     batch-commands.     (line    6)
* source (mysql client command):         batch-mode.         (line   90)
* source command, mysql:                 mysql-commands.     (line  204)
* source distribution, installing:       source-installation.
                                                             (line   14)
* source distributions, on Linux:        source-notes-linux. (line    6)
* SPACE():                               string-functions.   (line  645)
* spassword option, mysqlaccess:         mysqlaccess.        (line  138)
* Spatial Extensions in MySQL:           gis-introduction.   (line    6)
* speed, compiling:                      compile-and-link-options.
                                                             (line    6)
* speed, increasing with replication:    replication.        (line   13)
* speed, inserting:                      insert-speed.       (line    6)
* speed, linking:                        compile-and-link-options.
                                                             (line    6)
* speed, of queries <1>:                 select-speed.       (line    6)
* speed, of queries:                     select-optimization.
                                                             (line   25)
* sporadic-binlog-dump-fail option, mysqld: replication-options-binary-log.
                                                             (line  256)
* SQL mode:                              server-sql-mode.    (line    6)
* SQL mode, ALLOW_INVALID_DATES:         server-sql-mode.    (line   75)
* SQL mode, and replication:             replication-features-sql-mode.
                                                             (line    6)
* SQL mode, ANSI:                        server-sql-mode.    (line   43)
* SQL mode, ANSI_QUOTES:                 server-sql-mode.    (line   95)
* SQL mode, DB2:                         server-sql-mode.    (line  406)
* SQL mode, ERROR_FOR_DIVISION_BY_ZERO:  server-sql-mode.    (line  103)
* SQL mode, HIGH_NOT_PRECEDENCE:         server-sql-mode.    (line  113)
* SQL mode, IGNORE_SPACE:                server-sql-mode.    (line  129)
* SQL mode, MAXDB:                       server-sql-mode.    (line  411)
* SQL mode, MSSQL:                       server-sql-mode.    (line  417)
* SQL mode, MYSQL323:                    server-sql-mode.    (line  422)
* SQL mode, MYSQL40:                     server-sql-mode.    (line  426)
* SQL mode, NO_AUTO_CREATE_USER:         server-sql-mode.    (line  154)
* SQL mode, NO_AUTO_VALUE_ON_ZERO:       server-sql-mode.    (line  160)
* SQL mode, NO_BACKSLASH_ESCAPES:        server-sql-mode.    (line  179)
* SQL mode, NO_DIR_IN_CREATE:            server-sql-mode.    (line  186)
* SQL mode, NO_ENGINE_SUBSTITUTION:      server-sql-mode.    (line  192)
* SQL mode, NO_FIELD_OPTIONS:            server-sql-mode.    (line  209)
* SQL mode, NO_KEY_OPTIONS:              server-sql-mode.    (line  215)
* SQL mode, NO_TABLE_OPTIONS:            server-sql-mode.    (line  221)
* SQL mode, NO_UNSIGNED_SUBTRACTION:     server-sql-mode.    (line  227)
* SQL mode, NO_ZERO_DATE:                server-sql-mode.    (line  274)
* SQL mode, NO_ZERO_IN_DATE:             server-sql-mode.    (line  281)
* SQL mode, ONLY_FULL_GROUP_BY <1>:      group-by-hidden-columns.
                                                             (line    6)
* SQL mode, ONLY_FULL_GROUP_BY:          server-sql-mode.    (line  290)
* SQL mode, ORACLE:                      server-sql-mode.    (line  430)
* SQL mode, PIPES_AS_CONCAT:             server-sql-mode.    (line  303)
* SQL mode, POSTGRESQL:                  server-sql-mode.    (line  436)
* SQL mode, REAL_AS_FLOAT:               server-sql-mode.    (line  308)
* SQL mode, strict:                      server-sql-mode.    (line   70)
* SQL mode, STRICT_ALL_TABLES:           server-sql-mode.    (line  314)
* SQL mode, STRICT_TRANS_TABLES:         server-sql-mode.    (line   48)
* SQL mode, TRADITIONAL:                 server-sql-mode.    (line   56)
* SQL node (MySQL Cluster), defined:     mysql-cluster-basics.
                                                             (line    6)
* SQL nodes (MySQL Cluster):             mysql-cluster-programs-mysqld.
                                                             (line    6)
* SQL scripts:                           mysql.              (line   15)
* SQL statements relating to MySQL Cluster: mysql-cluster-sql-statements.
                                                             (line    6)
* SQL statements, replication masters:   replication-master-sql.
                                                             (line   12)
* SQL statements, replication slaves:    replication-slave-sql.
                                                             (line   17)
* SQL, defined:                          what-is-mysql.      (line   39)
* SQL-92, extensions to:                 compatibility.      (line   15)
* sql-mode option, mysqld:               server-options.     (line 1667)
* sql_auto_is_null session variable:     server-system-variables.
                                                             (line 4585)
* SQL_BIG_RESULT:                        select.             (line  392)
* sql_big_selects session variable:      server-system-variables.
                                                             (line 4612)
* SQL_BUFFER_RESULT:                     select.             (line  401)
* sql_buffer_result session variable:    server-system-variables.
                                                             (line 4635)
* SQL_CACHE <1>:                         select.             (line  413)
* SQL_CACHE:                             query-cache-in-select.
                                                             (line    9)
* SQL_CALC_FOUND_ROWS:                   select.             (line  408)
* sql_log_bin session variable:          server-system-variables.
                                                             (line 4653)
* sql_log_off session variable:          server-system-variables.
                                                             (line 4668)
* sql_log_update session variable:       server-system-variables.
                                                             (line 4684)
* sql_mode system variable:              server-system-variables.
                                                             (line 4702)
* SQL_NO_CACHE <1>:                      select.             (line  413)
* SQL_NO_CACHE:                          query-cache-in-select.
                                                             (line    9)
* sql_notes session variable:            server-system-variables.
                                                             (line 4745)
* sql_quote_show_create session variable: server-system-variables.
                                                             (line 4755)
* sql_safe_updates session variable:     server-system-variables.
                                                             (line 4764)
* sql_select_limit system variable:      server-system-variables.
                                                             (line 4773)
* sql_slave_skip_counter:                set-global-sql-slave-skip-counter.
                                                             (line    6)
* sql_slave_skip_counter system variable: replication-options-slave.
                                                             (line 1255)
* SQL_SMALL_RESULT:                      select.             (line  392)
* sql_warnings session variable:         server-system-variables.
                                                             (line 4803)
* sql_yacc.cc problems:                  compilation-problems.
                                                             (line   37)
* SQRT():                                mathematical-functions.
                                                             (line  532)
* square brackets:                       data-types.         (line   41)
* srcdir option, mysql_install_db:       mysql-install-db.   (line   69)
* SRID():                                general-geometry-property-functions.
                                                             (line   51)
* SSH:                                   windows-and-ssh.    (line    6)
* SSL:                                   secure-using-ssl.   (line    6)
* SSL and X509 Basics:                   secure-connections. (line   13)
* SSL command options:                   ssl-options.        (line    6)
* ssl option:                            ssl-options.        (line   37)
* SSL options:                           connecting.         (line  204)
* SSL options, mysql:                    mysql-command-options.
                                                             (line  482)
* SSL options, mysqladmin:               mysqladmin.         (line  375)
* SSL options, mysqlcheck:               mysqlcheck.         (line  327)
* SSL options, mysqld <1>:               privileges-options. (line  127)
* SSL options, mysqld:                   server-options.     (line 1537)
* SSL options, mysqldump:                mysqldump.          (line  869)
* SSL options, mysqlimport:              mysqlimport.        (line  251)
* SSL options, mysqlshow:                mysqlshow.          (line  180)
* SSL related options:                   grant.              (line  488)
* ssl-ca option:                         ssl-options.        (line   66)
* ssl-capath option:                     ssl-options.        (line   70)
* ssl-cert option:                       ssl-options.        (line   75)
* ssl-cipher option:                     ssl-options.        (line   80)
* ssl-key option:                        ssl-options.        (line   99)
* ssl-verify-server-cert option:         ssl-options.        (line  112)
* ssl_ca system variable:                server-system-variables.
                                                             (line 4809)
* ssl_capath system variable:            server-system-variables.
                                                             (line 4830)
* ssl_cert system variable:              server-system-variables.
                                                             (line 4851)
* ssl_cipher system variable:            server-system-variables.
                                                             (line 4872)
* ssl_key system variable:               server-system-variables.
                                                             (line 4893)
* standalone option, mysqld:             server-options.     (line 1543)
* standalone option, mysqlmanager:       instance-manager-command-options.
                                                             (line  168)
* Standard Monitor, InnoDB:              innodb-monitors.    (line   12)
* Standard SQL, differences from <1>:    grant.              (line  601)
* Standard SQL, differences from:        differences-from-ansi.
                                                             (line   14)
* Standard SQL, extensions to <1>:       extensions-to-ansi. (line    6)
* Standard SQL, extensions to:           compatibility.      (line   15)
* standards compatibility:               compatibility.      (line   15)
* START BACKUP, NOWAIT:                  mysql-cluster-backup-using-management-client.
                                                             (line   36)
* START BACKUP, syntax:                  mysql-cluster-backup-using-management-client.
                                                             (line   10)
* START BACKUP, WAIT COMPLETED:          mysql-cluster-backup-using-management-client.
                                                             (line   53)
* START BACKUP, WAIT STARTED:            mysql-cluster-backup-using-management-client.
                                                             (line   45)
* START command (MySQL Cluster):         mysql-cluster-mgm-client-commands.
                                                             (line   34)
* START SLAVE:                           start-slave.        (line    6)
* START TRANSACTION:                     commit.             (line    6)
* START, XA transactions:                xa-statements.      (line    6)
* start-datetime option, mysqlbinlog:    mysqlbinlog.        (line  316)
* start-position option, mysqlbinlog:    mysqlbinlog.        (line  330)
* start_row option, mysql_find_rows:     mysql-find-rows.    (line   47)
* StartFailureTimeout:                   mysql-cluster-ndbd-definition.
                                                             (line 1338)
* Starting many servers:                 multiple-servers.   (line   13)
* starting slave, thread state:          slave-connection-thread-states.
                                                             (line   37)
* starting, comments:                    ansi-diff-comments. (line    6)
* starting, mysqld:                      changing-mysql-user.
                                                             (line    6)
* starting, the server:                  unix-postinstallation.
                                                             (line   49)
* starting, the server automatically:    automatic-start.    (line    6)
* StartPartialTimeout:                   mysql-cluster-ndbd-definition.
                                                             (line 1291)
* StartPartitionedTimeout:               mysql-cluster-ndbd-definition.
                                                             (line 1315)
* StartPoint():                          linestring-property-functions.
                                                             (line   64)
* STARTUP Events (MySQL Cluster):        mysql-cluster-log-events.
                                                             (line   56)
* startup options, default:              option-files.       (line   11)
* startup parameters:                    server-parameters.  (line    6)
* startup parameters, mysql:             mysql-command-options.
                                                             (line    6)
* startup parameters, mysqladmin:        mysqladmin.         (line  209)
* startup parameters, tuning:            system-optimization.
                                                             (line    6)
* statefile option, comp_err:            comp-err.           (line   66)
* statements, compound:                  sql-syntax-compound-statements.
                                                             (line   16)
* statements, GRANT:                     adding-users.       (line    6)
* statements, INSERT:                    adding-users.       (line  116)
* statements, replication masters:       replication-master-sql.
                                                             (line   12)
* statements, replication slaves:        replication-slave-sql.
                                                             (line   17)
* statically, compiling:                 source-configuration-options.
                                                             (line  342)
* STATISTICS Events (MySQL Cluster):     mysql-cluster-log-events.
                                                             (line  175)
* STATISTICS, INFORMATION_SCHEMA table:  statistics-table.   (line    6)
* Statistics, thread command:            thread-commands.    (line  124)
* statistics, thread state:              general-thread-states.
                                                             (line  306)
* stats option, myisam_ftdump:           myisam-ftdump.      (line   74)
* stats_method myisamchk variable:       myisamchk-general-options.
                                                             (line   53)
* STATUS command (MySQL Cluster):        mysql-cluster-mgm-client-commands.
                                                             (line   86)
* status command, mysql:                 mysql-commands.     (line  209)
* status command, results:               mysqladmin.         (line  158)
* status option, mysqlshow:              mysqlshow.          (line  186)
* status variables <1>:                  show-status.        (line    6)
* status variables:                      server-status-variables.
                                                             (line    6)
* status, tables:                        show-table-status.  (line    6)
* STD():                                 group-by-functions. (line  237)
* STDDEV():                              group-by-functions. (line  245)
* STDDEV_POP():                          group-by-functions. (line  253)
* STDDEV_SAMP():                         group-by-functions. (line  262)
* STOP command (MySQL Cluster):          mysql-cluster-mgm-client-commands.
                                                             (line   53)
* STOP SLAVE:                            stop-slave.         (line    6)
* stop-datetime option, mysqlbinlog:     mysqlbinlog.        (line  339)
* stop-position option, mysqlbinlog:     mysqlbinlog.        (line  349)
* StopOnError:                           mysql-cluster-ndbd-definition.
                                                             (line 1193)
* stopping, the server:                  automatic-start.    (line    6)
* stopword list, user-defined:           fulltext-fine-tuning.
                                                             (line   40)
* storage engine, ARCHIVE:               archive-storage-engine.
                                                             (line    6)
* storage engines, choosing:             storage-engines.    (line   19)
* storage nodes - see data nodes, ndbd:  mysql-cluster-programs-ndbd.
                                                             (line    6)
* storage requirements, data type:       storage-requirements.
                                                             (line    6)
* storage space, minimizing:             data-size.          (line    6)
* storage_engine system variable:        server-system-variables.
                                                             (line 4913)
* stored functions:                      stored-routines.    (line   13)
* stored functions, and INSERT DELAYED:  insert.             (line  230)
* stored procedures:                     stored-routines.    (line   13)
* stored programs <1>:                   stored-programs-views.
                                                             (line   15)
* stored programs:                       sql-syntax-compound-statements.
                                                             (line   16)
* stored routine, restrictions:          stored-program-restrictions.
                                                             (line    6)
* stored routines, LAST_INSERT_ID():     stored-routines-last-insert-id.
                                                             (line    6)
* stored routines, metadata:             stored-routines-metadata.
                                                             (line    6)
* storing result in query cache, thread state: query-cache-thread-states.
                                                             (line   29)
* storing row into queue, thread state:  delayed-insert-thread-states.
                                                             (line   39)
* STR_TO_DATE():                         date-and-time-functions.
                                                             (line  798)
* STRAIGHT_JOIN <1>:                     join.               (line    6)
* STRAIGHT_JOIN <2>:                     select.             (line  375)
* STRAIGHT_JOIN <3>:                     left-join-optimization.
                                                             (line   38)
* STRAIGHT_JOIN <4>:                     explain-output.     (line  648)
* STRAIGHT_JOIN:                         using-explain.      (line   26)
* STRCMP():                              string-comparison-functions.
                                                             (line  182)
* strict SQL mode:                       server-sql-mode.    (line   70)
* STRICT_ALL_TABLES SQL mode:            server-sql-mode.    (line  314)
* STRICT_TRANS_TABLES SQL mode:          server-sql-mode.    (line   48)
* string collating:                      string-collating.   (line    6)
* string comparison functions:           string-comparison-functions.
                                                             (line    6)
* string comparisons, case sensitivity:  string-comparison-functions.
                                                             (line   17)
* string concatenation <1>:              string-functions.   (line  193)
* string concatenation:                  string-literals.    (line   12)
* string functions:                      string-functions.   (line   11)
* string literal introducer <1>:         charset-literal.    (line   11)
* string literal introducer:             string-literals.    (line   33)
* string replacement, replace utility:   replace-utility.    (line    6)
* string types <1>:                      storage-requirements.
                                                             (line  145)
* string types:                          string-types.       (line   14)
* StringMemory:                          mysql-cluster-ndbd-definition.
                                                             (line  420)
* strings, defined:                      string-literals.    (line    6)
* strings, escape sequences:             string-literals.    (line    6)
* strings, nondelimited:                 date-and-time-literals.
                                                             (line  116)
* striping, defined:                     disk-issues.        (line   27)
* SUBDATE():                             date-and-time-functions.
                                                             (line  862)
* subqueries:                            subqueries.         (line   20)
* subqueries, correlated:                correlated-subqueries.
                                                             (line    6)
* subqueries, errors:                    subquery-errors.    (line    6)
* subqueries, rewriting as joins:        rewriting-subqueries.
                                                             (line    6)
* subqueries, with ALL:                  all-subqueries.     (line    6)
* subqueries, with ANY, IN, SOME:        any-in-some-subqueries.
                                                             (line    6)
* subqueries, with EXISTS:               exists-and-not-exists-subqueries.
                                                             (line    6)
* subqueries, with NOT EXISTS:           exists-and-not-exists-subqueries.
                                                             (line    6)
* subqueries, with ROW:                  row-subqueries.     (line    6)
* subquery:                              subqueries.         (line   20)
* subquery optimization:                 in-subquery-optimization.
                                                             (line    6)
* subquery, restrictions:                subquery-restrictions.
                                                             (line    6)
* subselects:                            subqueries.         (line   20)
* SUBSTR():                              string-functions.   (line  652)
* SUBSTRING():                           string-functions.   (line  657)
* SUBSTRING_INDEX():                     string-functions.   (line  690)
* SUBTIME():                             date-and-time-functions.
                                                             (line  880)
* subtraction (-):                       arithmetic-functions.
                                                             (line   62)
* suffix option, make_win_src_distribution: make-win-src-distribution.
                                                             (line   36)
* suffix option, mysqlhotcopy:           mysqlhotcopy.       (line  178)
* SUM():                                 group-by-functions. (line  269)
* SUM(DISTINCT):                         group-by-functions. (line  269)
* superuser:                             default-privileges. (line    6)
* superuser option, mysqlaccess:         mysqlaccess.        (line  148)
* support, for operating systems:        supported-os.       (line    6)
* suppression, default values:           constraint-invalid-data.
                                                             (line    6)
* Sybase compatibility:                  use.                (line   27)
* symbolic links <1>:                    windows-symbolic-links.
                                                             (line    6)
* symbolic links:                        symbolic-links.     (line   12)
* symbolic-links option, mysqld:         server-options.     (line 1553)
* symbols-file option, resolve_stack_dump: resolve-stack-dump.
                                                             (line   29)
* SymDifference():                       spatial-operators.  (line   31)
* sync-bdb-logs option, mysqld:          bdb-start.          (line   76)
* sync_binlog system variable:           replication-options-binary-log.
                                                             (line  340)
* sync_frm system variable:              server-system-variables.
                                                             (line 4925)
* Syncing ndb table schema operation and binlog, thread state: mysql-cluster-thread-states.
                                                             (line   20)
* syntax conventions:                    manual-conventions. (line    8)
* syntax, regular expression:            regexp.             (line    6)
* SYSDATE():                             date-and-time-functions.
                                                             (line  891)
* sysdate-is-now option, mysqld:         server-options.     (line 1709)
* system command, mysql:                 mysql-commands.     (line  216)
* System lock, thread state:             general-thread-states.
                                                             (line  312)
* system optimization:                   system-optimization.
                                                             (line    6)
* system table, optimizer <1>:           select.             (line  381)
* system table, optimizer:               explain-output.     (line  193)
* system variable, auto_increment_increment: replication-options-master.
                                                             (line   21)
* system variable, auto_increment_offset: replication-options-master.
                                                             (line  224)
* system variable, automatic_sp_privileges: server-system-variables.
                                                             (line  543)
* system variable, back_log:             server-system-variables.
                                                             (line  573)
* system variable, basedir:              server-system-variables.
                                                             (line  609)
* system variable, bdb_cache_size:       server-system-variables.
                                                             (line  631)
* system variable, bdb_home:             server-system-variables.
                                                             (line  654)
* system variable, bdb_log_buffer_size:  server-system-variables.
                                                             (line  674)
* system variable, bdb_logdir:           server-system-variables.
                                                             (line  698)
* system variable, bdb_max_lock:         server-system-variables.
                                                             (line  718)
* system variable, bdb_shared_data:      server-system-variables.
                                                             (line  744)
* system variable, bdb_tmpdir:           server-system-variables.
                                                             (line  760)
* system variable, binlog_cache_size:    server-system-variables.
                                                             (line  794)
* system variable, bulk_insert_buffer_size: server-system-variables.
                                                             (line  834)
* system variable, character_set_client: server-system-variables.
                                                             (line  870)
* system variable, character_set_connection: server-system-variables.
                                                             (line  908)
* system variable, character_set_database: server-system-variables.
                                                             (line  923)
* system variable, character_set_filesystem: server-system-variables.
                                                             (line  962)
* system variable, character_set_results: server-system-variables.
                                                             (line  993)
* system variable, character_set_server: server-system-variables.
                                                             (line 1008)
* system variable, character_set_system: server-system-variables.
                                                             (line 1027)
* system variable, character_sets_dir:   server-system-variables.
                                                             (line 1041)
* system variable, collation_connection: server-system-variables.
                                                             (line 1060)
* system variable, collation_database:   server-system-variables.
                                                             (line 1074)
* system variable, collation_server:     server-system-variables.
                                                             (line 1113)
* system variable, completion_type:      server-system-variables.
                                                             (line 1132)
* system variable, concurrent_insert:    server-system-variables.
                                                             (line 1174)
* system variable, connect_timeout:      server-system-variables.
                                                             (line 1214)
* system variable, datadir:              server-system-variables.
                                                             (line 1248)
* system variable, date_format:          server-system-variables.
                                                             (line 1269)
* system variable, datetime_format:      server-system-variables.
                                                             (line 1273)
* system variable, default_week_format:  server-system-variables.
                                                             (line 1277)
* system variable, delay_key_write:      server-system-variables.
                                                             (line 1300)
* system variable, delayed_insert_limit: server-system-variables.
                                                             (line 1347)
* system variable, delayed_insert_timeout: server-system-variables.
                                                             (line 1381)
* system variable, delayed_queue_size:   server-system-variables.
                                                             (line 1402)
* system variable, div_precision_increment: server-system-variables.
                                                             (line 1436)
* system variable, engine_condition_pushdown: server-system-variables.
                                                             (line 1479)
* system variable, expire_logs_days:     server-system-variables.
                                                             (line 1527)
* system variable, flush:                server-system-variables.
                                                             (line 1555)
* system variable, flush_time:           server-system-variables.
                                                             (line 1577)
* system variable, ft_boolean_syntax:    server-system-variables.
                                                             (line 1627)
* system variable, ft_max_word_len:      server-system-variables.
                                                             (line 1664)
* system variable, ft_min_word_len:      server-system-variables.
                                                             (line 1689)
* system variable, ft_query_expansion_limit: server-system-variables.
                                                             (line 1715)
* system variable, ft_stopword_file:     server-system-variables.
                                                             (line 1737)
* system variable, group_concat_max_len: server-system-variables.
                                                             (line 1769)
* system variable, have_archive:         server-system-variables.
                                                             (line 1801)
* system variable, have_bdb:             server-system-variables.
                                                             (line 1806)
* system variable, have_blackhole_engine: server-system-variables.
                                                             (line 1811)
* system variable, have_compress:        server-system-variables.
                                                             (line 1816)
* system variable, have_crypt:           server-system-variables.
                                                             (line 1822)
* system variable, have_csv:             server-system-variables.
                                                             (line 1827)
* system variable, have_example_engine:  server-system-variables.
                                                             (line 1832)
* system variable, have_federated_engine: server-system-variables.
                                                             (line 1837)
* system variable, have_geometry:        server-system-variables.
                                                             (line 1842)
* system variable, have_innodb:          server-system-variables.
                                                             (line 1846)
* system variable, have_isam:            server-system-variables.
                                                             (line 1851)
* system variable, have_merge_engine:    server-system-variables.
                                                             (line 1857)
* system variable, have_openssl:         server-system-variables.
                                                             (line 1863)
* system variable, have_query_cache:     server-system-variables.
                                                             (line 1868)
* system variable, have_raid:            server-system-variables.
                                                             (line 1873)
* system variable, have_rtree_keys:      server-system-variables.
                                                             (line 1879)
* system variable, have_ssl:             server-system-variables.
                                                             (line 1884)
* system variable, have_symlink:         server-system-variables.
                                                             (line 1894)
* system variable, hostname:             server-system-variables.
                                                             (line 1901)
* system variable, init_connect:         server-system-variables.
                                                             (line 1923)
* system variable, init_file:            server-system-variables.
                                                             (line 1964)
* system variable, init_slave:           replication-options-slave.
                                                             (line 1057)
* system variable, interactive_timeout:  server-system-variables.
                                                             (line 2002)
* system variable, join_buffer_size:     server-system-variables.
                                                             (line 2027)
* system variable, keep_files_on_create: server-system-variables.
                                                             (line 2058)
* system variable, key_buffer_size:      server-system-variables.
                                                             (line 2093)
* system variable, key_cache_age_threshold: server-system-variables.
                                                             (line 2168)
* system variable, key_cache_block_size: server-system-variables.
                                                             (line 2203)
* system variable, key_cache_division_limit: server-system-variables.
                                                             (line 2226)
* system variable, language:             server-system-variables.
                                                             (line 2250)
* system variable, large_files_support:  server-system-variables.
                                                             (line 2273)
* system variable, large_page_size:      server-system-variables.
                                                             (line 2309)
* system variable, large_pages:          server-system-variables.
                                                             (line 2283)
* system variable, lc_time_names:        server-system-variables.
                                                             (line 2338)
* system variable, license:              server-system-variables.
                                                             (line 2360)
* system variable, local_infile:         server-system-variables.
                                                             (line 2374)
* system variable, locked_in_memory:     server-system-variables.
                                                             (line 2388)
* system variable, log:                  server-system-variables.
                                                             (line 2398)
* system variable, log_bin:              server-system-variables.
                                                             (line 2403)
* system variable, log_bin_trust_function_creators: server-system-variables.
                                                             (line 2418)
* system variable, log_bin_trust_routine_creators: server-system-variables.
                                                             (line 2451)
* system variable, log_error:            server-system-variables.
                                                             (line 2461)
* system variable, log_queries_not_using_indexes: server-system-variables.
                                                             (line 2480)
* system variable, log_slow_queries:     server-system-variables.
                                                             (line 2501)
* system variable, log_warnings:         server-system-variables.
                                                             (line 2524)
* system variable, long_query_time:      server-system-variables.
                                                             (line 2553)
* system variable, low_priority_updates: server-system-variables.
                                                             (line 2581)
* system variable, lower_case_file_system: server-system-variables.
                                                             (line 2607)
* system variable, lower_case_table_names: server-system-variables.
                                                             (line 2629)
* system variable, max_allowed_packet:   server-system-variables.
                                                             (line 2676)
* system variable, max_binlog_cache_size: replication-options-binary-log.
                                                             (line  285)
* system variable, max_binlog_size:      replication-options-binary-log.
                                                             (line  307)
* system variable, max_connect_errors:   server-system-variables.
                                                             (line 2723)
* system variable, max_connections:      server-system-variables.
                                                             (line 2760)
* system variable, max_delayed_threads:  server-system-variables.
                                                             (line 2780)
* system variable, max_error_count:      server-system-variables.
                                                             (line 2811)
* system variable, max_heap_table_size:  server-system-variables.
                                                             (line 2835)
* system variable, max_insert_delayed_threads: server-system-variables.
                                                             (line 2880)
* system variable, max_join_size:        server-system-variables.
                                                             (line 2894)
* system variable, max_length_for_sort_data: server-system-variables.
                                                             (line 2935)
* system variable, max_prepared_stmt_count: server-system-variables.
                                                             (line 2958)
* system variable, max_relay_log_size:   server-system-variables.
                                                             (line 2990)
* system variable, max_seeks_for_key:    server-system-variables.
                                                             (line 3020)
* system variable, max_sort_length:      server-system-variables.
                                                             (line 3057)
* system variable, max_sp_recursion_depth: server-system-variables.
                                                             (line 3081)
* system variable, max_tmp_tables:       server-system-variables.
                                                             (line 3113)
* system variable, max_user_connections: server-system-variables.
                                                             (line 3145)
* system variable, max_write_lock_count: server-system-variables.
                                                             (line 3186)
* system variable, myisam_data_pointer_size: server-system-variables.
                                                             (line 3217)
* system variable, myisam_max_extra_sort_file_size: server-system-variables.
                                                             (line 3251)
* system variable, myisam_max_sort_file_size: server-system-variables.
                                                             (line 3255)
* system variable, myisam_mmap_size:     server-system-variables.
                                                             (line 3284)
* system variable, myisam_recover_options: server-system-variables.
                                                             (line 3319)
* system variable, myisam_repair_threads: server-system-variables.
                                                             (line 3329)
* system variable, myisam_sort_buffer_size: server-system-variables.
                                                             (line 3366)
* system variable, myisam_stats_method:  server-system-variables.
                                                             (line 3403)
* system variable, named_pipe:           server-system-variables.
                                                             (line 3445)
* system variable, net_buffer_length:    server-system-variables.
                                                             (line 3461)
* system variable, net_read_timeout:     server-system-variables.
                                                             (line 3498)
* system variable, net_retry_count:      server-system-variables.
                                                             (line 3530)
* system variable, net_write_timeout:    server-system-variables.
                                                             (line 3571)
* system variable, new:                  server-system-variables.
                                                             (line 3599)
* system variable, old_passwords:        server-system-variables.
                                                             (line 3623)
* system variable, one_shot:             server-system-variables.
                                                             (line 3644)
* system variable, open_files_limit:     server-system-variables.
                                                             (line 3649)
* system variable, optimizer_prune_level: server-system-variables.
                                                             (line 3675)
* system variable, optimizer_search_depth: server-system-variables.
                                                             (line 3701)
* system variable, pid_file:             server-system-variables.
                                                             (line 3730)
* system variable, plugin_dir:           server-system-variables.
                                                             (line 3750)
* system variable, port:                 server-system-variables.
                                                             (line 3777)
* system variable, preload_buffer_size:  server-system-variables.
                                                             (line 3798)
* system variable, prepared_stmt_count:  server-system-variables.
                                                             (line 3821)
* system variable, protocol_version:     server-system-variables.
                                                             (line 3858)
* system variable, pseudo_thread_id:     server-system-variables.
                                                             (line 3871)
* system variable, query_alloc_block_size: server-system-variables.
                                                             (line 3884)
* system variable, query_cache_limit:    server-system-variables.
                                                             (line 3922)
* system variable, query_cache_min_res_unit: server-system-variables.
                                                             (line 3953)
* system variable, query_cache_size:     server-system-variables.
                                                             (line 3987)
* system variable, query_cache_type:     server-system-variables.
                                                             (line 4027)
* system variable, query_cache_wlock_invalidate: server-system-variables.
                                                             (line 4067)
* system variable, query_prealloc_size:  server-system-variables.
                                                             (line 4093)
* system variable, range_alloc_block_size: server-system-variables.
                                                             (line 4150)
* system variable, read_buffer_size:     server-system-variables.
                                                             (line 4188)
* system variable, read_only:            server-system-variables.
                                                             (line 4222)
* system variable, read_rnd_buffer_size: server-system-variables.
                                                             (line 4272)
* system variable, relay_log_index:      replication-options-slave.
                                                             (line 1086)
* system variable, relay_log_info_file:  replication-options-slave.
                                                             (line 1107)
* system variable, relay_log_purge:      server-system-variables.
                                                             (line 4308)
* system variable, relay_log_space_limit: server-system-variables.
                                                             (line 4328)
* system variable, secure_auth:          server-system-variables.
                                                             (line 4358)
* system variable, secure_file_priv:     server-system-variables.
                                                             (line 4387)
* system variable, server_id:            server-system-variables.
                                                             (line 4412)
* system variable, shared_memory:        server-system-variables.
                                                             (line 4437)
* system variable, shared_memory_base_name: server-system-variables.
                                                             (line 4448)
* system variable, skip_external_locking: server-system-variables.
                                                             (line 4461)
* system variable, skip_networking:      server-system-variables.
                                                             (line 4467)
* system variable, skip_show_database:   server-system-variables.
                                                             (line 4476)
* system variable, slave_compressed_protocol: replication-options-slave.
                                                             (line 1132)
* system variable, slave_load_tmpdir:    replication-options-slave.
                                                             (line 1152)
* system variable, slave_net_timeout:    replication-options-slave.
                                                             (line 1173)
* system variable, slave_skip_errors:    replication-options-slave.
                                                             (line 1196)
* system variable, slave_transaction_retries: replication-options-slave.
                                                             (line 1214)
* system variable, slow_launch_time:     server-system-variables.
                                                             (line 4491)
* system variable, socket:               server-system-variables.
                                                             (line 4511)
* system variable, sort_buffer_size:     server-system-variables.
                                                             (line 4538)
* system variable, sql_mode:             server-system-variables.
                                                             (line 4702)
* system variable, sql_select_limit:     server-system-variables.
                                                             (line 4773)
* system variable, sql_slave_skip_counter: replication-options-slave.
                                                             (line 1255)
* system variable, ssl_ca:               server-system-variables.
                                                             (line 4809)
* system variable, ssl_capath:           server-system-variables.
                                                             (line 4830)
* system variable, ssl_cert:             server-system-variables.
                                                             (line 4851)
* system variable, ssl_cipher:           server-system-variables.
                                                             (line 4872)
* system variable, ssl_key:              server-system-variables.
                                                             (line 4893)
* system variable, storage_engine:       server-system-variables.
                                                             (line 4913)
* system variable, sync_binlog:          replication-options-binary-log.
                                                             (line  340)
* system variable, sync_frm:             server-system-variables.
                                                             (line 4925)
* system variable, system_time_zone:     server-system-variables.
                                                             (line 4947)
* system variable, table_cache:          server-system-variables.
                                                             (line 4972)
* system variable, table_lock_wait_timeout: server-system-variables.
                                                             (line 5004)
* system variable, table_type:           server-system-variables.
                                                             (line 5026)
* system variable, thread_cache_size:    server-system-variables.
                                                             (line 5045)
* system variable, thread_concurrency:   server-system-variables.
                                                             (line 5079)
* system variable, thread_stack:         server-system-variables.
                                                             (line 5105)
* system variable, time_format:          server-system-variables.
                                                             (line 5145)
* system variable, time_zone:            server-system-variables.
                                                             (line 5149)
* system variable, timed_mutexes:        server-system-variables.
                                                             (line 5171)
* system variable, tmp_table_size:       server-system-variables.
                                                             (line 5212)
* system variable, tmpdir:               server-system-variables.
                                                             (line 5250)
* system variable, transaction_alloc_block_size: server-system-variables.
                                                             (line 5287)
* system variable, transaction_prealloc_size: server-system-variables.
                                                             (line 5324)
* system variable, tx_isolation:         server-system-variables.
                                                             (line 5369)
* system variable, updatable_views_with_limit: server-system-variables.
                                                             (line 5428)
* system variable, version:              server-system-variables.
                                                             (line 5464)
* system variable, version_bdb:          server-system-variables.
                                                             (line 5486)
* system variable, version_comment:      server-system-variables.
                                                             (line 5490)
* system variable, version_compile_machine: server-system-variables.
                                                             (line 5515)
* system variable, version_compile_os:   server-system-variables.
                                                             (line 5528)
* system variable, wait_timeout:         server-system-variables.
                                                             (line 5541)
* system variables <1>:                  show-variables.     (line    6)
* system variables <2>:                  using-system-variables.
                                                             (line   11)
* system variables:                      server-system-variables.
                                                             (line    6)
* system variables, and replication:     replication-features-variables.
                                                             (line    6)
* system, privilege:                     privilege-system.   (line   16)
* system, security:                      security.           (line   15)
* system_time_zone system variable:      server-system-variables.
                                                             (line 4947)
* SYSTEM_USER():                         information-functions.
                                                             (line  517)
* tab (\t) <1>:                          load-data.          (line  418)
* tab (\t):                              string-literals.    (line   74)
* tab option, mysqldump:                 mysqldump.          (line  875)
* table aliases:                         select.             (line  160)
* table cache:                           table-cache.        (line    6)
* table description, myisamchk:          myisamchk-table-info.
                                                             (line    6)
* Table Dump, thread command:            thread-commands.    (line  128)
* table is full <1>:                     full-table.         (line    6)
* table is full:                         server-system-variables.
                                                             (line  781)
* Table is full errors, MySQL Cluster:   faqs-mysql-cluster. (line    6)
* Table lock, thread state:              general-thread-states.
                                                             (line  325)
* Table Monitor, InnoDB <1>:             innodb-troubleshooting-datadict.
                                                             (line   57)
* Table Monitor, InnoDB:                 innodb-monitors.    (line   12)
* table names, case sensitivity:         identifier-case-sensitivity.
                                                             (line    6)
* table names, case-sensitivity:         extensions-to-ansi. (line   38)
* table option, mysql:                   mysql-command-options.
                                                             (line  488)
* table option, mysqlaccess:             mysqlaccess.        (line  152)
* table scans, avoiding:                 how-to-avoid-table-scan.
                                                             (line    6)
* table types, choosing:                 storage-engines.    (line   19)
* table, changing <1>:                   alter-table-problems.
                                                             (line    6)
* table, changing:                       alter-table.        (line   10)
* table, deleting:                       drop-table.         (line    6)
* table, rebuilding:                     rebuilding-tables.  (line    6)
* table, repair:                         rebuilding-tables.  (line    6)
* table, row size:                       storage-requirements.
                                                             (line   24)
* table-level locking:                   internal-locking.   (line    6)
* table_cache:                           table-cache.        (line    6)
* table_cache system variable:           server-system-variables.
                                                             (line 4972)
* table_lock_wait_timeout system variable: server-system-variables.
                                                             (line 5004)
* TABLE_PRIVILEGES, INFORMATION_SCHEMA table: table-privileges-table.
                                                             (line    6)
* table_type system variable:            server-system-variables.
                                                             (line 5026)
* tables option, mysqlcheck:             mysqlcheck.         (line  333)
* tables option, mysqldump:              mysqldump.          (line  902)
* tables, BDB:                           bdb-storage-engine. (line   15)
* tables, Berkeley DB:                   bdb-storage-engine. (line   15)
* tables, BLACKHOLE:                     blackhole-storage-engine.
                                                             (line    6)
* tables, checking:                      myisamchk-check-options.
                                                             (line    6)
* tables, closing:                       table-cache.        (line    6)
* tables, compressed:                    myisampack.         (line    6)
* tables, compressed format:             compressed-format.  (line    6)
* tables, const:                         explain-output.     (line  198)
* tables, constant:                      where-optimizations.
                                                             (line   50)
* tables, copying <1>:                   create-table-select.
                                                             (line    6)
* tables, copying:                       create-table.       (line  747)
* tables, counting rows:                 counting-rows.      (line    6)
* tables, creating:                      creating-tables.    (line    6)
* tables, CSV:                           csv-storage-engine. (line    6)
* tables, defragment:                    dynamic-format.     (line   16)
* tables, defragmenting <1>:             optimize-table.     (line    6)
* tables, defragmenting:                 myisam-maintenance-schedule.
                                                             (line   38)
* tables, deleting rows:                 deleting-from-related-tables.
                                                             (line    6)
* tables, displaying:                    mysqlshow.          (line    6)
* tables, displaying status:             show-table-status.  (line    6)
* tables, dumping <1>:                   mysqlhotcopy.       (line    6)
* tables, dumping:                       mysqldump.          (line    6)
* tables, dynamic:                       dynamic-format.     (line    6)
* tables, error checking:                myisam-check.       (line    6)
* tables, EXAMPLE:                       example-storage-engine.
                                                             (line    6)
* tables, FEDERATED:                     federated-storage-engine.
                                                             (line   12)
* tables, flush:                         mysqladmin.         (line  183)
* tables, fragmentation:                 optimize-table.     (line    6)
* tables, HEAP:                          memory-storage-engine.
                                                             (line    6)
* tables, host:                          request-access.     (line  148)
* tables, improving performance:         data-size.          (line    6)
* tables, information:                   myisamchk-table-info.
                                                             (line    6)
* tables, information about:             getting-information.
                                                             (line    6)
* TABLES, INFORMATION_SCHEMA table:      tables-table.       (line    6)
* tables, InnoDB:                        innodb-storage-engine.
                                                             (line   23)
* tables, loading data:                  loading-tables.     (line    6)
* tables, maintenance:                   mysqlcheck.         (line    6)
* tables, maintenance schedule:          myisam-maintenance-schedule.
                                                             (line    6)
* tables, maximum size:                  table-size-limit.   (line    6)
* tables, MEMORY:                        memory-storage-engine.
                                                             (line    6)
* tables, MERGE:                         merge-storage-engine.
                                                             (line   11)
* tables, merging:                       merge-storage-engine.
                                                             (line   11)
* tables, multiple:                      multiple-tables.    (line    6)
* tables, MyISAM:                        myisam-storage-engine.
                                                             (line   13)
* tables, names:                         identifiers.        (line   12)
* tables, open:                          table-cache.        (line    6)
* tables, opening:                       table-cache.        (line    6)
* tables, optimizing:                    myisam-optimization.
                                                             (line    6)
* tables, partitioning:                  merge-storage-engine.
                                                             (line   11)
* tables, repair:                        mysqlcheck.         (line    6)
* tables, repairing:                     myisam-repair.      (line    6)
* tables, retrieving data:               retrieving-data.    (line   18)
* tables, selecting columns:             selecting-columns.  (line    6)
* tables, selecting rows:                selecting-rows.     (line    6)
* tables, sorting rows:                  sorting-rows.       (line    6)
* tables, symbolic links:                symbolic-links-to-tables.
                                                             (line    6)
* tables, system:                        explain-output.     (line  193)
* tables, too many:                      creating-many-tables.
                                                             (line    6)
* tables, unique ID for last row:        getting-unique-id.  (line    6)
* tables, updating:                      ansi-diff-transactions.
                                                             (line    6)
* Tablespace Monitor, InnoDB <1>:        innodb-monitors.    (line   12)
* Tablespace Monitor, InnoDB <2>:        innodb-file-space.  (line   48)
* Tablespace Monitor, InnoDB:            innodb-backup.      (line  110)
* TAN():                                 mathematical-functions.
                                                             (line  543)
* tar option, make_win_src_distribution: make-win-src-distribution.
                                                             (line   40)
* tar, problems on Solaris <1>:          solaris.            (line   11)
* tar, problems on Solaris:              solaris-installation.
                                                             (line    6)
* tbl-status option, mysql_tableinfo:    mysql-tableinfo.    (line  129)
* tc-heuristic-recover option, mysqld:   server-options.     (line 1733)
* Tcl API:                               apis-tcl.           (line    6)
* tcp-ip option, mysqld_multi:           mysqld-multi.       (line  159)
* TCP/IP <1>:                            windows-testing.    (line    6)
* TCP/IP:                                windows-select-server.
                                                             (line   30)
* tee command, mysql:                    mysql-commands.     (line  222)
* tee option, mysql:                     mysql-command-options.
                                                             (line  494)
* temp-pool option, mysqld:              server-options.     (line 1750)
* temporary file, write access:          mysql-install-db-problems.
                                                             (line   70)
* temporary files:                       temporary-files.    (line    6)
* temporary tables, and replication:     replication-features-temptables.
                                                             (line    6)
* temporary tables, internal:            internal-temporary-tables.
                                                             (line    6)
* temporary tables, problems:            temporary-table-problems.
                                                             (line    6)
* terminal monitor, defined:             tutorial.           (line   16)
* test option, myisampack:               myisampack.         (line   97)
* testing mysqld, mysqltest:             mysql-test-suite.   (line    6)
* testing, connection to the server:     connection-access.  (line    6)
* testing, installation:                 unix-postinstallation.
                                                             (line   49)
* testing, of MySQL releases:            choosing-version.   (line  119)
* testing, postinstallation:             postinstallation.   (line   11)
* TEXT columns, default values:          blob.               (line   63)
* TEXT columns, indexing <1>:            create-table.       (line  359)
* TEXT columns, indexing:                column-indexes.     (line   15)
* TEXT data type <1>:                    blob.               (line    6)
* TEXT data type:                        string-type-overview.
                                                             (line  228)
* text files, importing <1>:             mysqlimport.        (line    6)
* text files, importing:                 batch-commands.     (line    6)
* TEXT, size:                            storage-requirements.
                                                             (line  188)
* thread cache:                          connection-threads. (line    6)
* thread command, Binlog Dump:           thread-commands.    (line    8)
* thread command, Change user:           thread-commands.    (line   13)
* thread command, Close stmt:            thread-commands.    (line   17)
* thread command, Connect:               thread-commands.    (line   21)
* thread command, Connect Out:           thread-commands.    (line   25)
* thread command, Create DB:             thread-commands.    (line   29)
* thread command, Daemon:                thread-commands.    (line   33)
* thread command, Debug:                 thread-commands.    (line   38)
* thread command, Delayed insert:        thread-commands.    (line   42)
* thread command, Drop DB:               thread-commands.    (line   46)
* thread command, Error:                 thread-commands.    (line   50)
* thread command, Execute:               thread-commands.    (line   52)
* thread command, Fetch:                 thread-commands.    (line   56)
* thread command, Field List:            thread-commands.    (line   61)
* thread command, Init DB:               thread-commands.    (line   65)
* thread command, Kill:                  thread-commands.    (line   69)
* thread command, Long Data:             thread-commands.    (line   73)
* thread command, Ping:                  thread-commands.    (line   78)
* thread command, Prepare:               thread-commands.    (line   82)
* thread command, Processlist:           thread-commands.    (line   86)
* thread command, Query:                 thread-commands.    (line   90)
* thread command, Quit:                  thread-commands.    (line   94)
* thread command, Refresh:               thread-commands.    (line   98)
* thread command, Register Slave:        thread-commands.    (line  103)
* thread command, Reset stmt:            thread-commands.    (line  107)
* thread command, Set option:            thread-commands.    (line  111)
* thread command, Shutdown:              thread-commands.    (line  116)
* thread command, Sleep:                 thread-commands.    (line  120)
* thread command, Statistics:            thread-commands.    (line  124)
* thread command, Table Dump:            thread-commands.    (line  128)
* thread command, Time:                  thread-commands.    (line  132)
* thread commands:                       thread-commands.    (line    6)
* thread state, After create:            general-thread-states.
                                                             (line   11)
* thread state, allocating local table:  delayed-insert-thread-states.
                                                             (line   17)
* thread state, Analyzing:               general-thread-states.
                                                             (line   18)
* thread state, Changing master:         slave-connection-thread-states.
                                                             (line    9)
* thread state, Checking master version: slave-io-thread-states.
                                                             (line   20)
* thread state, checking permissions:    general-thread-states.
                                                             (line   23)
* thread state, checking privileges on cached query: query-cache-thread-states.
                                                             (line    9)
* thread state, checking query cache for query: query-cache-thread-states.
                                                             (line   14)
* thread state, Checking table:          general-thread-states.
                                                             (line   28)
* thread state, cleaning up:             general-thread-states.
                                                             (line   32)
* thread state, closing tables:          general-thread-states.
                                                             (line   37)
* thread state, Committing events to binlog: mysql-cluster-thread-states.
                                                             (line    6)
* thread state, Connecting to master:    slave-io-thread-states.
                                                             (line   16)
* thread state, converting HEAP to MyISAM: general-thread-states.
                                                             (line   44)
* thread state, copy to tmp table:       general-thread-states.
                                                             (line   49)
* thread state, Copying to group table:  general-thread-states.
                                                             (line   55)
* thread state, Copying to tmp table:    general-thread-states.
                                                             (line   60)
* thread state, Copying to tmp table on disk: general-thread-states.
                                                             (line   64)
* thread state, Creating delayed handler: delayed-insert-thread-states.
                                                             (line   22)
* thread state, Creating index:          general-thread-states.
                                                             (line   72)
* thread state, Creating sort index:     general-thread-states.
                                                             (line   77)
* thread state, creating table:          general-thread-states.
                                                             (line   82)
* thread state, Creating table from master dump: slave-connection-thread-states.
                                                             (line   14)
* thread state, Creating tmp table:      general-thread-states.
                                                             (line   87)
* thread state, deleting from main table: general-thread-states.
                                                             (line   94)
* thread state, deleting from reference tables: general-thread-states.
                                                             (line  100)
* thread state, discard_or_import_tablespace: general-thread-states.
                                                             (line  105)
* thread state, end:                     general-thread-states.
                                                             (line  110)
* thread state, executing:               general-thread-states.
                                                             (line  117)
* thread state, Execution of init_command: general-thread-states.
                                                             (line  121)
* thread state, Finished reading one binlog; switching to next binlog: master-thread-states.
                                                             (line   17)
* thread state, Flushing tables:         general-thread-states.
                                                             (line  132)
* thread state, freeing items:           general-thread-states.
                                                             (line  126)
* thread state, FULLTEXT initialization: general-thread-states.
                                                             (line  137)
* thread state, got handler lock:        delayed-insert-thread-states.
                                                             (line   26)
* thread state, got old table:           delayed-insert-thread-states.
                                                             (line   32)
* thread state, Has read all relay log; waiting for the slave I/O thread to update it: slave-sql-thread-states.
                                                             (line   18)
* thread state, Has sent all binlog to slave; waiting for binlog to be updated: master-thread-states.
                                                             (line   22)
* thread state, init:                    general-thread-states.
                                                             (line  142)
* thread state, insert:                  delayed-insert-thread-states.
                                                             (line   74)
* thread state, invalidating query cache entries: query-cache-thread-states.
                                                             (line   19)
* thread state, Killed:                  general-thread-states.
                                                             (line  158)
* thread state, Killing slave:           slave-connection-thread-states.
                                                             (line   21)
* thread state, Locked:                  general-thread-states.
                                                             (line  167)
* thread state, logging slow query:      general-thread-states.
                                                             (line  171)
* thread state, login:                   general-thread-states.
                                                             (line  180)
* thread state, Making temp file:        slave-sql-thread-states.
                                                             (line   25)
* thread state, NULL:                    general-thread-states.
                                                             (line  175)
* thread state, Opening master dump table: slave-connection-thread-states.
                                                             (line   25)
* thread state, Opening mysql.ndb_apply_status: mysql-cluster-thread-states.
                                                             (line    8)
* thread state, Opening table:           general-thread-states.
                                                             (line  185)
* thread state, Opening tables:          general-thread-states.
                                                             (line  185)
* thread state, optimizing:              general-thread-states.
                                                             (line  194)
* thread state, preparing:               general-thread-states.
                                                             (line  198)
* thread state, Processing events:       mysql-cluster-thread-states.
                                                             (line   10)
* thread state, Processing events from schema table: mysql-cluster-thread-states.
                                                             (line   14)
* thread state, Purging old relay logs:  general-thread-states.
                                                             (line  202)
* thread state, query end:               general-thread-states.
                                                             (line  206)
* thread state, Queueing master event to the relay log: slave-io-thread-states.
                                                             (line   57)
* thread state, Reading event from the relay log: slave-sql-thread-states.
                                                             (line   13)
* thread state, Reading from net:        general-thread-states.
                                                             (line  211)
* thread state, Reading master dump table data: slave-connection-thread-states.
                                                             (line   29)
* thread state, Rebuilding the index on master dump table: slave-connection-thread-states.
                                                             (line   33)
* thread state, Reconnecting after a failed binlog dump request: slave-io-thread-states.
                                                             (line   45)
* thread state, Reconnecting after a failed master event read: slave-io-thread-states.
                                                             (line   70)
* thread state, Registering slave on master: slave-io-thread-states.
                                                             (line   25)
* thread state, Removing duplicates:     general-thread-states.
                                                             (line  215)
* thread state, removing tmp table:      general-thread-states.
                                                             (line  222)
* thread state, rename:                  general-thread-states.
                                                             (line  228)
* thread state, rename result table:     general-thread-states.
                                                             (line  232)
* thread state, Reopen tables:           general-thread-states.
                                                             (line  238)
* thread state, Repair by sorting:       general-thread-states.
                                                             (line  244)
* thread state, Repair done:             general-thread-states.
                                                             (line  248)
* thread state, Repair with keycache:    general-thread-states.
                                                             (line  253)
* thread state, Requesting binlog dump:  slave-io-thread-states.
                                                             (line   30)
* thread state, reschedule:              delayed-insert-thread-states.
                                                             (line   78)
* thread state, Rolling back:            general-thread-states.
                                                             (line  258)
* thread state, Saving state:            general-thread-states.
                                                             (line  262)
* thread state, Searching rows for update: general-thread-states.
                                                             (line  269)
* thread state, Sending binlog event to slave: master-thread-states.
                                                             (line   11)
* thread state, sending cached result to client: query-cache-thread-states.
                                                             (line   24)
* thread state, setup:                   general-thread-states.
                                                             (line  283)
* thread state, Shutting down:           mysql-cluster-thread-states.
                                                             (line   18)
* thread state, Sorting for group:       general-thread-states.
                                                             (line  288)
* thread state, Sorting for order:       general-thread-states.
                                                             (line  292)
* thread state, Sorting index:           general-thread-states.
                                                             (line  296)
* thread state, Sorting result:          general-thread-states.
                                                             (line  301)
* thread state, starting slave:          slave-connection-thread-states.
                                                             (line   37)
* thread state, statistics:              general-thread-states.
                                                             (line  306)
* thread state, storing result in query cache: query-cache-thread-states.
                                                             (line   29)
* thread state, storing row into queue:  delayed-insert-thread-states.
                                                             (line   39)
* thread state, Syncing ndb table schema operation and binlog: mysql-cluster-thread-states.
                                                             (line   20)
* thread state, System lock:             general-thread-states.
                                                             (line  312)
* thread state, Table lock:              general-thread-states.
                                                             (line  325)
* thread state, update:                  delayed-insert-thread-states.
                                                             (line   44)
* thread state, Updating:                general-thread-states.
                                                             (line  331)
* thread state, updating main table:     general-thread-states.
                                                             (line  335)
* thread state, updating reference tables: general-thread-states.
                                                             (line  341)
* thread state, upgrading lock:          delayed-insert-thread-states.
                                                             (line   83)
* thread state, User lock:               general-thread-states.
                                                             (line  346)
* thread state, waiting for delay_list:  delayed-insert-thread-states.
                                                             (line   46)
* thread state, Waiting for event from ndbcluster: mysql-cluster-thread-states.
                                                             (line   25)
* thread state, Waiting for first event from ndbcluster: mysql-cluster-thread-states.
                                                             (line   30)
* thread state, waiting for handler insert: delayed-insert-thread-states.
                                                             (line   53)
* thread state, waiting for handler lock: delayed-insert-thread-states.
                                                             (line   58)
* thread state, waiting for handler open: delayed-insert-thread-states.
                                                             (line   64)
* thread state, Waiting for INSERT:      delayed-insert-thread-states.
                                                             (line   88)
* thread state, Waiting for master to send event: slave-io-thread-states.
                                                             (line   49)
* thread state, Waiting for master update: slave-io-thread-states.
                                                             (line   12)
* thread state, Waiting for ndbcluster binlog update to reach current position: mysql-cluster-thread-states.
                                                             (line   32)
* thread state, Waiting for ndbcluster to start: mysql-cluster-thread-states.
                                                             (line   34)
* thread state, Waiting for release of readlock: general-thread-states.
                                                             (line  353)
* thread state, Waiting for schema epoch: mysql-cluster-thread-states.
                                                             (line   36)
* thread state, Waiting for slave mutex on exit <1>: slave-sql-thread-states.
                                                             (line   31)
* thread state, Waiting for slave mutex on exit: slave-io-thread-states.
                                                             (line   84)
* thread state, Waiting for table:       general-thread-states.
                                                             (line  359)
* thread state, Waiting for tables:      general-thread-states.
                                                             (line  359)
* thread state, Waiting for the next event in relay log: slave-sql-thread-states.
                                                             (line    9)
* thread state, Waiting for the slave SQL thread to free enough relay log space: slave-io-thread-states.
                                                             (line   76)
* thread state, Waiting on cond:         general-thread-states.
                                                             (line  373)
* thread state, Waiting to finalize termination: master-thread-states.
                                                             (line   29)
* thread state, Waiting to get readlock: general-thread-states.
                                                             (line  378)
* thread state, Waiting to reconnect after a failed binlog dump request: slave-io-thread-states.
                                                             (line   37)
* thread state, Waiting to reconnect after a failed master event read: slave-io-thread-states.
                                                             (line   62)
* thread state, Writing to net:          general-thread-states.
                                                             (line  384)
* thread states, delayed inserts:        delayed-insert-thread-states.
                                                             (line    6)
* thread states, general:                general-thread-states.
                                                             (line    6)
* thread states, MySQL Cluster:          mysql-cluster-thread-states.
                                                             (line    6)
* thread states, query cache:            query-cache-thread-states.
                                                             (line    6)
* thread states, replication master:     master-thread-states.
                                                             (line    6)
* thread states, replication slave <1>:  slave-connection-thread-states.
                                                             (line    6)
* thread states, replication slave <2>:  slave-sql-thread-states.
                                                             (line    6)
* thread states, replication slave:      slave-io-thread-states.
                                                             (line    6)
* thread support:                        supported-os.       (line    6)
* thread_cache_size system variable:     server-system-variables.
                                                             (line 5045)
* thread_concurrency system variable:    server-system-variables.
                                                             (line 5079)
* thread_stack system variable:          server-system-variables.
                                                             (line 5105)
* threaded clients:                      threaded-clients.   (line    6)
* threads <1>:                           mysql-internals.    (line   11)
* threads <2>:                           show-processlist.   (line    6)
* threads:                               mysqladmin.         (line  165)
* threads, display:                      show-processlist.   (line    6)
* threads, monitoring <1>:               extended-show.      (line   99)
* threads, monitoring:                   show-processlist.   (line    6)
* TIME data type <1>:                    time.               (line    6)
* TIME data type:                        date-and-time-type-overview.
                                                             (line   63)
* time literals:                         date-and-time-literals.
                                                             (line    6)
* time types:                            storage-requirements.
                                                             (line  132)
* time zone problems:                    timezone-problems.  (line    6)
* time zone tables:                      mysql-tzinfo-to-sql.
                                                             (line    6)
* time zones, and replication:           replication-features-timezone.
                                                             (line    6)
* time zones, leap seconds:              time-zone-leap-seconds.
                                                             (line    6)
* time zones, support:                   time-zone-support.  (line   11)
* time zones, upgrading:                 time-zone-upgrades. (line    6)
* TIME():                                date-and-time-functions.
                                                             (line  931)
* Time, thread command:                  thread-commands.    (line  132)
* time_format system variable:           server-system-variables.
                                                             (line 5145)
* TIME_FORMAT():                         date-and-time-functions.
                                                             (line 1014)
* TIME_TO_SEC():                         date-and-time-functions.
                                                             (line 1029)
* time_zone system variable:             server-system-variables.
                                                             (line 5149)
* TimeBetweenGlobalCheckpoints:          mysql-cluster-ndbd-definition.
                                                             (line 1450)
* TimeBetweenInactiveTransactionAbortCheck: mysql-cluster-ndbd-definition.
                                                             (line 1483)
* TimeBetweenLocalCheckpoints:           mysql-cluster-ndbd-definition.
                                                             (line 1419)
* TimeBetweenWatchDogCheck:              mysql-cluster-ndbd-definition.
                                                             (line 1266)
* timed_mutexes system variable:         server-system-variables.
                                                             (line 5171)
* TIMEDIFF():                            date-and-time-functions.
                                                             (line  941)
* timeout <1>:                           insert-delayed.     (line  123)
* timeout <2>:                           miscellaneous-functions.
                                                             (line   40)
* timeout:                               server-system-variables.
                                                             (line 1214)
* timeout option, ndb_waiter:            mysql-cluster-programs-ndb-waiter.
                                                             (line   69)
* timeout, connect_timeout variable <1>: mysqladmin.         (line  407)
* timeout, connect_timeout variable:     mysql-command-options.
                                                             (line  580)
* timeout, shutdown_timeout variable:    mysqladmin.         (line  412)
* timeouts (replication):                replication-features-timeout.
                                                             (line    6)
* TIMESTAMP data type <1>:               datetime.           (line   10)
* TIMESTAMP data type:                   date-and-time-type-overview.
                                                             (line   31)
* timestamp session variable:            server-system-variables.
                                                             (line 5198)
* TIMESTAMP():                           date-and-time-functions.
                                                             (line  954)
* TIMESTAMP, and logs:                   upgrading-from-previous-series.
                                                             (line  329)
* TIMESTAMP, and NULL values:            problems-with-null. (line   71)
* TIMESTAMP, and replication <1>:        replication-features-timestamp.
                                                             (line    6)
* TIMESTAMP, and replication <2>:        replication-features-auto-increment.
                                                             (line    6)
* TIMESTAMP, and replication:            upgrading-from-previous-series.
                                                             (line  329)
* TIMESTAMPADD():                        date-and-time-functions.
                                                             (line  966)
* TIMESTAMPDIFF():                       date-and-time-functions.
                                                             (line  989)
* timezone option, mysqld_safe:          mysqld-safe.        (line  238)
* TINYBLOB data type:                    string-type-overview.
                                                             (line  201)
* TINYINT data type:                     numeric-type-overview.
                                                             (line   45)
* TINYTEXT data type:                    string-type-overview.
                                                             (line  208)
* tips, optimization:                    miscellaneous-optimization-tips.
                                                             (line    6)
* tmp option, make_win_src_distribution: make-win-src-distribution.
                                                             (line   49)
* tmp_table_size system variable:        server-system-variables.
                                                             (line 5212)
* TMPDIR environment variable <1>:       temporary-files.    (line    6)
* TMPDIR environment variable <2>:       programs-overview.  (line  329)
* TMPDIR environment variable <3>:       environment-variables.
                                                             (line   18)
* TMPDIR environment variable:           mysql-install-db-problems.
                                                             (line   83)
* tmpdir option, myisamchk:              myisamchk-repair-options.
                                                             (line  121)
* tmpdir option, myisampack:             myisampack.         (line  101)
* tmpdir option, mysql_upgrade:          mysql-upgrade.      (line  120)
* tmpdir option, mysqld:                 server-options.     (line 1795)
* tmpdir option, mysqlhotcopy:           mysqlhotcopy.       (line  182)
* tmpdir system variable:                server-system-variables.
                                                             (line 5250)
* to-last-log option, mysqlbinlog:       mysqlbinlog.        (line  358)
* TO_DAYS():                             date-and-time-functions.
                                                             (line 1038)
* TODO, symlinks:                        symbolic-links-to-tables.
                                                             (line   73)
* tools, command-line:                   mysql.              (line   15)
* tools, list of:                        tools-used-to-create-mysql.
                                                             (line    6)
* tools, mysqld_multi:                   mysqld-multi.       (line    6)
* tools, mysqld_safe:                    mysqld-safe.        (line    6)
* tools, safe_mysqld:                    mysqld-safe.        (line    6)
* Touches():                             functions-that-test-spatial-relationships-between-geometries.
                                                             (line   60)
* trace DBI method:                      using-gdb-on-mysqld.
                                                             (line   89)
* trace files (MySQL Cluster):           mysql-cluster-programs-ndbd.
                                                             (line  298)
* TRADITIONAL SQL mode:                  server-sql-mode.    (line   56)
* transaction isolation level:           set-transaction.    (line    6)
* transaction isolation level, READ COMMITTED: set-transaction.
                                                             (line   69)
* transaction isolation level, READ UNCOMMITTED: set-transaction.
                                                             (line   61)
* transaction isolation level, REPEATABLE READ: set-transaction.
                                                             (line   91)
* transaction isolation level, SERIALIZABLE: set-transaction.
                                                             (line  113)
* transaction-isolation option, mysqld:  server-options.     (line 1770)
* transaction-safe tables <1>:           innodb-storage-engine.
                                                             (line   23)
* transaction-safe tables:               ansi-diff-transactions.
                                                             (line    6)
* transaction_alloc_block_size system variable: server-system-variables.
                                                             (line 5287)
* transaction_prealloc_size system variable: server-system-variables.
                                                             (line 5324)
* transactional option, ndb_delete_all:  mysql-cluster-programs-ndb-delete-all.
                                                             (line   21)
* TransactionBufferMemory:               mysql-cluster-ndbd-definition.
                                                             (line  727)
* TransactionDeadlockDetectionTimeout:   mysql-cluster-ndbd-definition.
                                                             (line 1523)
* TransactionInactiveTimeout:            mysql-cluster-ndbd-definition.
                                                             (line 1502)
* transactions, and replication <1>:     replication-features-transactions.
                                                             (line    6)
* transactions, and replication:         replication-features-timeout.
                                                             (line    6)
* transactions, support <1>:             innodb-storage-engine.
                                                             (line   23)
* transactions, support:                 ansi-diff-transactions.
                                                             (line    6)
* Translators, list of:                  documenters-translators.
                                                             (line    6)
* trigger, creating:                     create-trigger.     (line    6)
* trigger, dropping:                     drop-trigger.       (line    6)
* trigger, restrictions:                 stored-program-restrictions.
                                                             (line    6)
* triggers <1>:                          triggers.           (line   11)
* triggers <2>:                          stored-programs-views.
                                                             (line   15)
* triggers:                              show-triggers.      (line    6)
* triggers option, mysqldump:            mysqldump.          (line  908)
* triggers, and INSERT DELAYED:          insert.             (line  230)
* triggers, and replication:             replication-features-triggers.
                                                             (line    6)
* TRIGGERS, INFORMATION_SCHEMA table:    triggers-table.     (line    6)
* triggers, LAST_INSERT_ID():            stored-routines-last-insert-id.
                                                             (line    6)
* triggers, metadata:                    trigger-metadata.   (line    6)
* TRIM():                                string-functions.   (line  706)
* troubleshooting, FreeBSD:              compilation-problems.
                                                             (line  136)
* troubleshooting, Solaris:              compilation-problems.
                                                             (line  136)
* TRUE <1>:                              boolean-literals.   (line    6)
* TRUE:                                  number-literals.    (line    6)
* TRUE, testing for:                     comparison-operators.
                                                             (line  130)
* TRUNCATE TABLE:                        truncate-table.     (line    6)
* TRUNCATE TABLE, and MySQL Cluster:     mysql-cluster-limitations-limits.
                                                             (line    9)
* TRUNCATE():                            mathematical-functions.
                                                             (line  552)
* tupscan option, ndb_select_all:        mysql-cluster-programs-ndb-select-all.
                                                             (line   68)
* tutorial:                              tutorial.           (line   16)
* tx_isolation system variable:          server-system-variables.
                                                             (line 5369)
* type codes, C prepared statement API:  c-api-prepared-statement-type-codes.
                                                             (line    6)
* type conversions <1>:                  comparison-operators.
                                                             (line   38)
* type conversions:                      type-conversion.    (line    6)
* type option, mysql_convert_table_format: mysql-convert-table-format.
                                                             (line   54)
* type option, ndb_config:               mysql-cluster-programs-ndb-config.
                                                             (line  186)
* type option, ndb_show_tables:          mysql-cluster-programs-ndb-show-tables.
                                                             (line   55)
* types, column:                         data-types.         (line   29)
* types, columns:                        choosing-types.     (line    6)
* types, data:                           data-types.         (line   29)
* types, date:                           storage-requirements.
                                                             (line  132)
* types, Date and Time:                  date-and-time-types.
                                                             (line   15)
* types, numeric:                        storage-requirements.
                                                             (line   83)
* types, of tables:                      storage-engines.    (line   19)
* types, portability:                    other-vendor-data-types.
                                                             (line    6)
* types, string:                         storage-requirements.
                                                             (line  145)
* types, strings:                        string-types.       (line   14)
* types, time:                           storage-requirements.
                                                             (line  132)
* typographical conventions:             manual-conventions. (line    8)
* TZ environment variable <1>:           timezone-problems.  (line    6)
* TZ environment variable:               environment-variables.
                                                             (line   18)
* tz-utc option, mysqldump:              mysqldump.          (line  915)
* UCASE():                               string-functions.   (line  725)
* UCS-2:                                 charset.            (line   22)
* ucs2 character set:                    charset-unicode-ucs2.
                                                             (line    6)
* UDFs <1>:                              drop-function-udf.  (line    6)
* UDFs:                                  create-function-udf.
                                                             (line    6)
* UDFs, compiling:                       udf-compiling.      (line    6)
* UDFs, defined:                         adding-functions.   (line   12)
* UDFs, return values:                   udf-return-values.  (line    6)
* ulimit:                                not-enough-file-handles.
                                                             (line   33)
* UMASK environment variable <1>:        file-permissions.   (line    6)
* UMASK environment variable:            environment-variables.
                                                             (line   18)
* UMASK_DIR environment variable <1>:    file-permissions.   (line   20)
* UMASK_DIR environment variable:        environment-variables.
                                                             (line   18)
* unary minus (-):                       arithmetic-functions.
                                                             (line   69)
* unbuffered option, mysql:              mysql-command-options.
                                                             (line  500)
* UNCOMPRESS():                          encryption-functions.
                                                             (line  348)
* UNCOMPRESSED_LENGTH():                 encryption-functions.
                                                             (line  361)
* UndoDataBuffer:                        mysql-cluster-ndbd-definition.
                                                             (line 1743)
* UndoIndexBuffer:                       mysql-cluster-ndbd-definition.
                                                             (line 1697)
* UNHEX():                               string-functions.   (line  729)
* Unicode:                               charset.            (line   22)
* Unicode Collation Algorithm:           charset-unicode-sets.
                                                             (line   70)
* UNION <1>:                             union.              (line    6)
* UNION:                                 searching-on-two-keys.
                                                             (line    6)
* Union():                               spatial-operators.  (line   36)
* UNIQUE:                                alter-table.        (line  266)
* unique ID:                             getting-unique-id.  (line    6)
* unique key, constraint:                constraint-primary-key.
                                                             (line    6)
* unique_checks session variable:        server-system-variables.
                                                             (line 5405)
* unique_subquery join type, optimizer:  explain-output.     (line  283)
* Unix <1>:                              connector-net.      (line   18)
* Unix:                                  connector-odbc.     (line   17)
* Unix, compiling clients on:            building-clients.   (line   25)
* UNIX_TIMESTAMP():                      date-and-time-functions.
                                                             (line 1095)
* UNKNOWN, testing for:                  comparison-operators.
                                                             (line  130)
* unloading, tables:                     retrieving-data.    (line   18)
* UNLOCK TABLES:                         lock-tables.        (line   12)
* unnamed views:                         from-clause-subqueries.
                                                             (line    6)
* unpack option, myisamchk:              myisamchk-repair-options.
                                                             (line  131)
* unqualified option, ndb_show_tables:   mysql-cluster-programs-ndb-show-tables.
                                                             (line   69)
* UNSIGNED <1>:                          numeric-types.      (line   15)
* UNSIGNED:                              numeric-type-overview.
                                                             (line    6)
* UNTIL:                                 repeat-statement.   (line    6)
* updatable views:                       view-updatability.  (line    6)
* updatable_views_with_limit system variable: server-system-variables.
                                                             (line 5428)
* UPDATE <1>:                            update.             (line    6)
* UPDATE:                                ansi-diff-update.   (line    6)
* update, thread state:                  delayed-insert-thread-states.
                                                             (line   44)
* update-state option, myisamchk:        myisamchk-check-options.
                                                             (line   62)
* updating main table, thread state:     general-thread-states.
                                                             (line  335)
* updating reference tables, thread state: general-thread-states.
                                                             (line  341)
* updating, releases of MySQL:           many-versions.      (line    6)
* updating, tables:                      ansi-diff-transactions.
                                                             (line    6)
* Updating, thread state:                general-thread-states.
                                                             (line  331)
* upgrades and downgrades (MySQL Cluster), compatibility between versions: mysql-cluster-upgrade-downgrade.
                                                             (line    6)
* upgrades, MySQL Cluster <1>:           mysql-cluster-rolling-restart.
                                                             (line    6)
* upgrades, MySQL Cluster:               mysql-cluster-upgrade-downgrade.
                                                             (line    6)
* upgrading <1>:                         upgrading.          (line   11)
* upgrading:                             upgrading-downgrading.
                                                             (line   14)
* upgrading lock, thread state:          delayed-insert-thread-states.
                                                             (line   83)
* upgrading MySQL:                       mysql-upgrade.      (line    6)
* upgrading tables, ISAM:                upgrading-from-previous-series.
                                                             (line  410)
* upgrading tables, RAID:                upgrading-from-previous-series.
                                                             (line  421)
* upgrading, different architecture:     copying-databases.  (line    6)
* upgrading, grant tables:               mysql-fix-privilege-tables.
                                                             (line    6)
* upgrading, to &current-series;:        upgrading-from-previous-series.
                                                             (line    6)
* UPPER():                               string-functions.   (line  772)
* uptime:                                mysqladmin.         (line  161)
* URLs for downloading MySQL:            getting-mysql.      (line    6)
* usage option, ndb_config:              mysql-cluster-programs-ndb-config.
                                                             (line   34)
* USE:                                   use.                (line    6)
* use command, mysql:                    mysql-commands.     (line  236)
* USE INDEX:                             index-hints.        (line    6)
* USE KEY:                               index-hints.        (line    6)
* use-frm option, mysqlcheck:            mysqlcheck.         (line  338)
* use-manager option, mysql.server:      mysql-server.       (line   63)
* use-mysqld_safe option, mysql.server:  mysql-server.       (line   58)
* useHexFormat option, ndb_select_all:   mysql-cluster-programs-ndb-select-all.
                                                             (line   43)
* user accounts, creating:               create-user.        (line    6)
* user accounts, renaming:               rename-user.        (line    6)
* user accounts, resource limits <1>:    grant.              (line  456)
* user accounts, resource limits <2>:    user-resources.     (line    6)
* user accounts, resource limits:        server-system-variables.
                                                             (line 3145)
* USER environment variable <1>:         connecting.         (line  231)
* USER environment variable:             environment-variables.
                                                             (line   18)
* User lock, thread state:               general-thread-states.
                                                             (line  346)
* user names, and passwords:             user-names.         (line    6)
* user option:                           connecting.         (line  210)
* user option, mysql:                    mysql-command-options.
                                                             (line  504)
* user option, mysql.server:             mysql-server.       (line   68)
* user option, mysql_convert_table_format: mysql-convert-table-format.
                                                             (line   59)
* user option, mysql_explain_log:        mysql-explain-log.  (line   53)
* user option, mysql_install_db:         mysql-install-db.   (line   76)
* user option, mysql_setpermission:      mysql-setpermission.
                                                             (line   55)
* user option, mysql_tableinfo:          mysql-tableinfo.    (line  135)
* user option, mysql_upgrade:            mysql-upgrade.      (line  125)
* user option, mysqlaccess:              mysqlaccess.        (line  156)
* user option, mysqladmin:               mysqladmin.         (line  381)
* user option, mysqlbinlog:              mysqlbinlog.        (line  366)
* user option, mysqlcheck:               mysqlcheck.         (line  344)
* user option, mysqld:                   server-options.     (line 1829)
* user option, mysqld_multi:             mysqld-multi.       (line  167)
* user option, mysqld_safe:              mysqld-safe.        (line  244)
* user option, mysqldump:                mysqldump.          (line  929)
* user option, mysqlhotcopy:             mysqlhotcopy.       (line  186)
* user option, mysqlimport:              mysqlimport.        (line  257)
* user option, mysqlmanager:             instance-manager-command-options.
                                                             (line  175)
* user option, mysqlshow:                mysqlshow.          (line  190)
* user privileges, adding:               adding-users.       (line    6)
* user privileges, deleting <1>:         drop-user.          (line    6)
* user privileges, deleting:             removing-users.     (line    6)
* user privileges, dropping <1>:         drop-user.          (line    6)
* user privileges, dropping:             removing-users.     (line    6)
* user table, sorting:                   connection-access.  (line  123)
* user variables:                        user-variables.     (line    6)
* user variables, and replication:       replication-features-variables.
                                                             (line    6)
* USER():                                information-functions.
                                                             (line  521)
* User-defined functions <1>:            drop-function-udf.  (line    6)
* User-defined functions:                create-function-udf.
                                                             (line    6)
* user-defined functions, adding <1>:    adding-udf.         (line   15)
* user-defined functions, adding:        adding-functions.   (line   12)
* USER_PRIVILEGES, INFORMATION_SCHEMA table: user-privileges-table.
                                                             (line    6)
* users, adding <1>:                     unix-postinstallation.
                                                             (line  363)
* users, adding:                         installing-source-distribution.
                                                             (line  198)
* users, deleting <1>:                   drop-user.          (line    6)
* users, deleting:                       removing-users.     (line    6)
* users, root:                           default-privileges. (line    6)
* using multiple disks to start data:    windows-symbolic-links.
                                                             (line    6)
* using MySQL Cluster programs:          mysql-cluster-programs.
                                                             (line   30)
* UTC_DATE():                            date-and-time-functions.
                                                             (line 1153)
* UTC_TIME():                            date-and-time-functions.
                                                             (line 1162)
* UTC_TIMESTAMP():                       date-and-time-functions.
                                                             (line 1171)
* UTF-8:                                 charset.            (line   22)
* utf8 character set:                    charset-unicode-utf8.
                                                             (line    6)
* utilities, program-development:        programs-overview.  (line  268)
* utility programs:                      programs-overview.  (line  167)
* UUID():                                miscellaneous-functions.
                                                             (line  201)
* valid numbers, examples:               number-literals.    (line    6)
* VALUES():                              miscellaneous-functions.
                                                             (line  250)
* VAR_POP():                             group-by-functions. (line  277)
* VAR_SAMP():                            group-by-functions. (line  287)
* VARBINARY data type <1>:               binary-varbinary.   (line    6)
* VARBINARY data type:                   string-type-overview.
                                                             (line  194)
* VARCHAR data type <1>:                 string-types.       (line   14)
* VARCHAR data type:                     string-type-overview.
                                                             (line  147)
* VARCHAR, size:                         storage-requirements.
                                                             (line  188)
* VARCHARACTER data type:                string-type-overview.
                                                             (line  147)
* variables, and replication:            replication-features-variables.
                                                             (line    6)
* variables, environment:                programs-overview.  (line  326)
* variables, mysqld:                     server-parameters.  (line   11)
* variables, server:                     show-variables.     (line    6)
* variables, status <1>:                 show-status.        (line    6)
* variables, status:                     server-status-variables.
                                                             (line    6)
* variables, system <1>:                 show-variables.     (line    6)
* variables, system <2>:                 using-system-variables.
                                                             (line   11)
* variables, system:                     server-system-variables.
                                                             (line    6)
* variables, user:                       user-variables.     (line    6)
* VARIANCE():                            group-by-functions. (line  295)
* verbose option, my_print_defaults:     my-print-defaults.  (line   57)
* verbose option, myisam_ftdump:         myisam-ftdump.      (line   79)
* verbose option, myisamchk:             myisamchk-general-options.
                                                             (line   32)
* verbose option, myisampack:            myisampack.         (line  106)
* verbose option, mysql:                 mysql-command-options.
                                                             (line  508)
* verbose option, mysql_convert_table_format: mysql-convert-table-format.
                                                             (line   63)
* verbose option, mysql_install_db:      mysql-install-db.   (line   85)
* verbose option, mysql_upgrade:         mysql-upgrade.      (line  130)
* verbose option, mysql_waitpid:         mysql-waitpid.      (line   31)
* verbose option, mysqladmin:            mysqladmin.         (line  385)
* verbose option, mysqlcheck:            mysqlcheck.         (line  348)
* verbose option, mysqld:                server-options.     (line 1864)
* verbose option, mysqld_multi:          mysqld-multi.       (line  172)
* verbose option, mysqldump:             mysqldump.          (line  933)
* verbose option, mysqldumpslow:         mysqldumpslow.      (line  103)
* verbose option, mysqlimport:           mysqlimport.        (line  261)
* verbose option, mysqlshow:             mysqlshow.          (line  194)
* verbose option, perror:                perror.             (line   52)
* version option, comp_err:              comp-err.           (line   71)
* version option, my_print_defaults:     my-print-defaults.  (line   61)
* version option, myisamchk:             myisamchk-general-options.
                                                             (line   38)
* version option, myisampack:            myisampack.         (line  111)
* version option, mysql:                 mysql-command-options.
                                                             (line  515)
* version option, mysql_config:          mysql-config.       (line   47)
* version option, mysql_convert_table_format: mysql-convert-table-format.
                                                             (line   67)
* version option, mysql_waitpid:         mysql-waitpid.      (line   36)
* version option, mysqlaccess:           mysqlaccess.        (line  160)
* version option, mysqladmin:            mysqladmin.         (line  389)
* version option, mysqlbinlog:           mysqlbinlog.        (line  370)
* version option, mysqlcheck:            mysqlcheck.         (line  353)
* version option, mysqld:                server-options.     (line 1868)
* version option, mysqld_multi:          mysqld-multi.       (line  176)
* version option, mysqldump:             mysqldump.          (line  937)
* version option, mysqlimport:           mysqlimport.        (line  265)
* version option, mysqlmanager:          instance-manager-command-options.
                                                             (line  186)
* version option, mysqlshow:             mysqlshow.          (line  200)
* version option, ndb_config:            mysql-cluster-programs-ndb-config.
                                                             (line   45)
* version option, perror:                perror.             (line   57)
* version option, resolve_stack_dump:    resolve-stack-dump. (line   33)
* version option, resolveip:             resolveip.          (line   23)
* version system variable:               server-system-variables.
                                                             (line 5464)
* VERSION():                             information-functions.
                                                             (line  538)
* version, choosing:                     which-version.      (line   19)
* version, latest:                       getting-mysql.      (line    6)
* version_bdb system variable:           server-system-variables.
                                                             (line 5486)
* version_comment system variable:       server-system-variables.
                                                             (line 5490)
* version_compile_machine system variable: server-system-variables.
                                                             (line 5515)
* version_compile_os system variable:    server-system-variables.
                                                             (line 5528)
* vertical option, mysql:                mysql-command-options.
                                                             (line  519)
* vertical option, mysqladmin:           mysqladmin.         (line  393)
* Vietnamese:                            faqs-cjk.           (line    6)
* view, restrictions:                    view-restrictions.  (line    6)
* views <1>:                             views.              (line   13)
* views <2>:                             stored-programs-views.
                                                             (line   15)
* views:                                 create-view.        (line    6)
* views, algorithms:                     view-algorithms.    (line    6)
* views, and replication:                replication-features-views.
                                                             (line    6)
* VIEWS, INFORMATION_SCHEMA table:       views-table.        (line    6)
* Views, limitations:                    view-restrictions.  (line  111)
* views, metadata:                       view-metadata.      (line    6)
* Views, privileges:                     view-restrictions.  (line  111)
* Views, problems:                       view-restrictions.  (line  111)
* views, updatable <1>:                  view-updatability.  (line    6)
* views, updatable:                      create-view.        (line    6)
* virtual memory, problems while compiling: compilation-problems.
                                                             (line   37)
* Vision:                                connector-odbc-usagenotes-apptips-vision.
                                                             (line    6)
* Visual Objects:                        connector-odbc-usagenotes-apptips-microsoft-visualobjects.
                                                             (line    6)
* Visual Studio:                         windows-source-build-cmake.
                                                             (line    6)
* WAIT COMPLETED (START BACKUP command): mysql-cluster-backup-using-management-client.
                                                             (line   53)
* wait option, myisamchk:                myisamchk-general-options.
                                                             (line   42)
* wait option, myisampack:               myisampack.         (line  115)
* wait option, mysql:                    mysql-command-options.
                                                             (line  525)
* wait option, mysqladmin:               mysqladmin.         (line  398)
* WAIT STARTED (START BACKUP command):   mysql-cluster-backup-using-management-client.
                                                             (line   45)
* wait-timeout option, mysqlmanager:     instance-manager-command-options.
                                                             (line  190)
* wait_timeout system variable:          server-system-variables.
                                                             (line 5541)
* waiting for delay_list, thread state:  delayed-insert-thread-states.
                                                             (line   46)
* Waiting for event from ndbcluster, thread state: mysql-cluster-thread-states.
                                                             (line   25)
* Waiting for first event from ndbcluster, thread state: mysql-cluster-thread-states.
                                                             (line   30)
* waiting for handler insert, thread state: delayed-insert-thread-states.
                                                             (line   53)
* waiting for handler lock, thread state: delayed-insert-thread-states.
                                                             (line   58)
* waiting for handler open, thread state: delayed-insert-thread-states.
                                                             (line   64)
* Waiting for INSERT, thread state:      delayed-insert-thread-states.
                                                             (line   88)
* Waiting for master to send event, thread state: slave-io-thread-states.
                                                             (line   49)
* Waiting for master update, thread state: slave-io-thread-states.
                                                             (line   12)
* Waiting for ndbcluster binlog update to reach current position, thread state: mysql-cluster-thread-states.
                                                             (line   32)
* Waiting for ndbcluster to start, thread state: mysql-cluster-thread-states.
                                                             (line   34)
* Waiting for release of readlock, thread state: general-thread-states.
                                                             (line  353)
* Waiting for schema epoch, thread state: mysql-cluster-thread-states.
                                                             (line   36)
* Waiting for slave mutex on exit, thread state <1>: slave-sql-thread-states.
                                                             (line   31)
* Waiting for slave mutex on exit, thread state: slave-io-thread-states.
                                                             (line   84)
* Waiting for table, thread state:       general-thread-states.
                                                             (line  359)
* Waiting for tables, thread state:      general-thread-states.
                                                             (line  359)
* Waiting for the next event in relay log, thread state: slave-sql-thread-states.
                                                             (line    9)
* Waiting for the slave SQL thread to free enough relay log space, thread state: slave-io-thread-states.
                                                             (line   76)
* Waiting on cond, thread state:         general-thread-states.
                                                             (line  373)
* Waiting to finalize termination, thread state: master-thread-states.
                                                             (line   29)
* Waiting to get readlock, thread state: general-thread-states.
                                                             (line  378)
* Waiting to reconnect after a failed binlog dump request, thread state: slave-io-thread-states.
                                                             (line   37)
* Waiting to reconnect after a failed master event read, thread state: slave-io-thread-states.
                                                             (line   62)
* warning_count session variable:        server-system-variables.
                                                             (line 5580)
* warnings command, mysql:               mysql-commands.     (line  240)
* WEEK():                                date-and-time-functions.
                                                             (line 1180)
* WEEKDAY():                             date-and-time-functions.
                                                             (line 1239)
* WEEKOFYEAR():                          date-and-time-functions.
                                                             (line 1249)
* Well-Known Binary format:              gis-wkb-format.     (line    6)
* Well-Known Text format:                gis-wkt-format.     (line    6)
* WHERE:                                 where-optimizations.
                                                             (line    6)
* where option, mysqldump:               mysqldump.          (line  941)
* WHERE, with SHOW <1>:                  extended-show.      (line    6)
* WHERE, with SHOW:                      information-schema. (line   28)
* WHILE:                                 while-statement.    (line    6)
* WHILE, labels:                         statement-labels.   (line    6)
* widths, display:                       data-types.         (line   31)
* Wildcard character (%):                string-literals.    (line   77)
* Wildcard character (_):                string-literals.    (line   78)
* wildcards, and LIKE:                   mysql-indexes.      (line  111)
* wildcards, in account names:           account-names.      (line   72)
* wildcards, in mysql.columns_priv table: request-access.    (line   59)
* wildcards, in mysql.db table:          request-access.     (line   26)
* wildcards, in mysql.host table:        request-access.     (line   26)
* wildcards, in mysql.procs_priv table:  request-access.     (line   59)
* wildcards, in mysql.tables_priv table: request-access.     (line   59)
* Windows <1>:                           connector-net.      (line   18)
* Windows:                               connector-odbc.     (line   17)
* windows option, mysql_install_db:      mysql-install-db.   (line   89)
* Windows, compiling clients on:         building-clients.   (line   39)
* Windows, MySQL limitations:            limits-windows.     (line    6)
* Windows, path name separators:         option-files.       (line  183)
* Windows, upgrading:                    windows-upgrading.  (line    6)
* with-big-tables option:                source-configuration-options.
                                                             (line    6)
* with-big-tables option, configure:     source-configuration-options.
                                                             (line  474)
* with-client-ldflags option, configure: source-configuration-options.
                                                             (line  342)
* with-debug option, configure:          source-configuration-options.
                                                             (line  442)
* with-embedded-server option, configure: source-configuration-options.
                                                             (line  299)
* with-extra-charsets option, configure: source-configuration-options.
                                                             (line  427)
* with-tcp-port option, configure:       source-configuration-options.
                                                             (line  323)
* with-unix-socket-path option, configure: source-configuration-options.
                                                             (line  330)
* with-zlib-dir option, configure:       source-configuration-options.
                                                             (line  465)
* Within():                              functions-that-test-spatial-relationships-between-geometries.
                                                             (line   67)
* without-server option:                 source-configuration-options.
                                                             (line    6)
* without-server option, configure:      source-configuration-options.
                                                             (line  285)
* WKB format:                            gis-wkb-format.     (line    6)
* WKT format:                            gis-wkt-format.     (line    6)
* wrappers, Eiffel:                      apis-eiffel.        (line    6)
* write access, tmp:                     mysql-install-db-problems.
                                                             (line   70)
* write_buffer_size myisamchk variable:  myisamchk-general-options.
                                                             (line   53)
* Writing to net, thread state:          general-thread-states.
                                                             (line  384)
* X():                                   point-property-functions.
                                                             (line    9)
* X509/Certificate:                      secure-basics.      (line   31)
* XA BEGIN:                              xa-statements.      (line    6)
* XA COMMIT:                             xa-statements.      (line    6)
* XA PREPARE:                            xa-statements.      (line    6)
* XA RECOVER:                            xa-statements.      (line    6)
* XA ROLLBACK:                           xa-statements.      (line    6)
* XA START:                              xa-statements.      (line    6)
* XA transactions:                       xa.                 (line   11)
* XA transactions, restrictions:         xa-restrictions.    (line    6)
* XA transactions, transaction identifiers: xa-statements.   (line    6)
* xid, XA transaction identifier:        xa-statements.      (line    6)
* xml option, mysql:                     mysql-command-options.
                                                             (line  530)
* xml option, mysqldump:                 mysqldump.          (line  953)
* XOR, bitwise:                          bit-functions.      (line   38)
* XOR, logical:                          logical-operators.  (line   87)
* Y():                                   point-property-functions.
                                                             (line   21)
* yaSSL <1>:                             secure-using-ssl.   (line    6)
* yaSSL:                                 secure-connections. (line   13)
* YEAR data type <1>:                    year.               (line    6)
* YEAR data type:                        date-and-time-type-overview.
                                                             (line   70)
* YEAR():                                date-and-time-functions.
                                                             (line 1258)
* YEARWEEK():                            date-and-time-functions.
                                                             (line 1266)
* Yen sign (Japanese):                   faqs-cjk.           (line    6)
* ZEROFILL <1>:                          c-api-prepared-statement-problems.
                                                             (line   13)
* ZEROFILL <2>:                          numeric-types.      (line   15)
* ZEROFILL:                              numeric-type-overview.
                                                             (line    6)
* | (bitwise OR):                        bit-functions.      (line   20)
* || (logical OR):                       logical-operators.  (line   68)
* ~:                                     bit-functions.      (line   75)



Tag Table:
Node: Top167
Node: preface1800
Ref: legalnotice2858
Node: introduction8380
Node: manual-info11520
Node: manual-conventions13692
Node: what-is18822
Node: what-is-mysql19203
Node: history23410
Node: features24568
Node: mysql-nutshell34067
Node: development-history41271
Node: information-sources42878
Node: mailing-lists43487
Node: mailing-list-use48510
Node: forums49615
Node: irc50162
Node: mysql-enterprise-information51122
Node: bug-reports51912
Node: compatibility69287
Node: standards71924
Node: sql-mode72237
Node: ansi-mode73226
Node: extensions-to-ansi74423
Node: differences-from-ansi84309
Node: ansi-diff-select-into-table86046
Node: ansi-diff-update86952
Node: ansi-diff-transactions87541
Node: ansi-diff-foreign-keys96458
Node: ansi-diff-comments101238
Node: constraints103907
Node: constraint-primary-key105901
Node: constraint-invalid-data107271
Node: constraint-enum113150
Node: credits115766
Node: contributors116298
Node: documenters-translators125108
Node: packages127525
Node: tools-used-to-create-mysql128726
Node: supporters129756
Node: installing130694
Node: installation-overview132737
Node: installation-version133921
Node: installing-es137847
Node: installing-es-disttypes139082
Node: installing-es-upgrade140466
Node: installing-cs141276
Node: installing-cs-overview141711
Node: supported-os144612
Node: which-version148877
Node: choosing-version149670
Node: choosing-distribution-format156121
Node: many-versions159227
Node: mysql-binaries161105
Node: getting-mysql161859
Node: verifying-package-integrity162483
Node: verifying-md5-checksum163843
Node: checking-gpg-signature165537
Node: checking-rpm-signature171711
Node: installation-layouts173094
Ref: mysql-installation-layout-linuxrpm174718
Ref: mysql-installation-layout-genericbinary175711
Node: compiler-characteristics178418
Node: quick-standard-installation178988
Node: windows-installation179787
Node: windows-choosing-package185069
Node: windows-using-installer186930
Node: windows-install-wizard187870
Node: mysql-install-wizard-starting190442
Node: mysql-install-wizard-install-type192221
Node: mysql-install-wizard-custom-install193745
Node: mysql-install-wizard-confirmation-dialog194811
Node: mysql-install-wizard-changes196107
Node: mysql-install-wizard-upgrading199569
Node: mysql-config-wizard200405
Node: mysql-config-wizard-starting201969
Node: mysql-config-wizard-maintenance205174
Node: mysql-config-wizard-configuration-type206517
Node: mysql-config-wizard-server-type208292
Node: mysql-config-wizard-database-usage209978
Node: mysql-config-wizard-tablespace212173
Node: mysql-config-wizard-connections213272
Node: mysql-config-wizard-networking214723
Node: mysql-config-wizard-character-set216011
Node: mysql-config-wizard-service217218
Node: mysql-config-wizard-security219290
Node: mysql-config-wizard-confirmation220527
Node: windows-install-archive222307
Node: windows-extract-archive223585
Node: windows-create-option-file224772
Node: windows-select-server228121
Node: windows-server-first-start230154
Node: windows-start-command-line233767
Node: mysql-installation-windows-path236033
Node: windows-start-service238143
Node: windows-testing246901
Node: windows-troubleshooting248437
Node: windows-upgrading253566
Node: windows-postinstallation256623
Node: windows-source-build261060
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Node: linux-installation-rpm286573
Node: solaris-installation297783
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Ref: installation-i5os-notes310320
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Ref: binary-installation-createsysuser320415
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Node: source-installation323196
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Ref: option_configure_with-client-ldflags367382
Ref: option_configure_with-charset369817
Ref: option_configure_with-collation370529
Ref: option_configure_with-extra-charsets371089
Ref: option_configure_with-debug371661
Ref: option_configure_enable-thread-safe-client372399
Ref: option_configure_with-zlib-dir372720
Ref: option_configure_with-big-tables373263
Ref: option_configure_disable-grant-options373779
Ref: option_configure_enable-profiling374149
Node: compilation-problems374669
Ref: option_configure_with-low-memory376216
Node: compile-and-link-options382625
Node: postinstallation385802
Node: unix-postinstallation387258
Node: mysql-install-db-problems404182
Node: automatic-start411108
Node: starting-server418768
Node: default-privileges427638
Node: upgrading-downgrading439197
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Node: upgrading-from-early-5-0445858
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Node: rebuilding-tables496962
Node: copying-databases500668
Node: operating-system-specific-notes503666
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Node: linux-x86522652
Node: linux-sparc525123
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Node: linux-powerpc527106
Node: linux-mips527350
Node: linux-ia-64527661
Node: selinux528618
Node: macosx529351
Node: macosx-10-x529751
Node: macosx-server531055
Node: solaris531574
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Node: bsd-notes541776
Node: freebsd542335
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Node: bsdi4549924
Node: other-unix-notes551168
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Node: perl-support603072
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Node: tutorial614220
Node: connecting-disconnecting616245
Node: entering-queries618984
Node: database-use627856
Node: creating-database631095
Node: creating-tables633515
Node: loading-tables638012
Node: retrieving-data641623
Node: selecting-all642831
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Node: sorting-rows651000
Node: date-calculations653898
Node: working-with-null661521
Node: pattern-matching664066
Node: counting-rows671573
Node: multiple-tables676613
Node: getting-information681936
Node: batch-mode684990
Node: examples688209
Node: example-maximum-column690415
Node: example-maximum-row690772
Node: example-maximum-column-group691914
Node: example-maximum-column-group-row692453
Node: example-user-variables694134
Node: example-foreign-keys695227
Node: searching-on-two-keys699508
Node: calculating-days700473
Node: example-auto-increment701650
Node: apache706466
Node: programs707364
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Ref: option_general_host730605
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Node: program-options734949
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Node: setting-environment-variables771229
Node: programs-server774215
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Ref: option_mysqld_safe_help783664
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Ref: option_mysqld_safe_basedir784229
Ref: option_mysqld_safe_core-file-size784305
Ref: option_mysqld_safe_datadir784472
Ref: option_mysqld_safe_defaults-extra-file784534
Ref: option_mysqld_safe_defaults-file784845
Ref: option_mysqld_safe_ledir785034
Ref: option_mysqld_safe_log-error785221
Ref: option_mysqld_safe_mysqld785320
Ref: option_mysqld_safe_mysqld-version785748
Ref: option_mysqld_safe_nice786282
Ref: option_mysqld_safe_no-defaults786401
Ref: option_mysqld_safe_open-files-limit786530
Ref: option_mysqld_safe_pid-file786800
Ref: option_mysqld_safe_port786874
Ref: option_mysqld_safe_skip-kill-mysqld787092
Ref: option_mysqld_safe_socket787235
Ref: option_mysqld_safe_timezone787355
Ref: option_mysqld_safe_user787558
Node: mysql-server791512
Ref: option_mysql_server_basedir793167
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Ref: option_mysql_server_use-mysqld_safe793882
Ref: option_mysql_server_use-manager794038
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Node: mysqld-multi794285
Ref: option_mysqld_multi_no-defaults797267
Ref: option_mysqld_multi_defaults-file797322
Ref: option_mysqld_multi_defaults-extra-file797392
Ref: option_mysqld_multi_help798829
Ref: option_mysqld_multi_config-file798884
Ref: option_mysqld_multi_example799555
Ref: option_mysqld_multi_log799610
Ref: option_mysqld_multi_mysqladmin799730
Ref: option_mysqld_multi_mysqld799844
Ref: option_mysqld_multi_no-log800555
Ref: option_mysqld_multi_password800688
Ref: option_mysqld_multi_silent800915
Ref: option_mysqld_multi_tcp-ip800970
Ref: option_mysqld_multi_user801324
Ref: option_mysqld_multi_verbose801449
Ref: option_mysqld_multi_version801491
Node: programs-installation807612
Node: comp-err808696
Ref: option_comp_err_help809707
Ref: option_comp_err_charset809768
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Ref: option_comp_err_header_file810161
Ref: option_comp_err_in_file810284
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Ref: option_make_win_bin_dist_debug812375
Ref: option_make_win_bin_dist_embedded812472
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Node: make-win-src-distribution813178
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Ref: option_make_win_src_distribution_dirname814226
Ref: option_make_win_src_distribution_silent814296
Ref: option_make_win_src_distribution_suffix814366
Ref: option_make_win_src_distribution_tar814423
Ref: option_make_win_src_distribution_tmp814732
Node: mysqlbug814780
Node: mysql-fix-privilege-tables816192
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Ref: option_mysql_install_db_basedir821319
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Ref: option_mysql_install_db_skip-name-resolve821798
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Ref: option_mysql_install_db_user822237
Ref: option_mysql_install_db_verbose822616
Ref: option_mysql_install_db_windows822707
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Ref: option_mysql_upgrade_help830734
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Ref: option_mysql_upgrade_force831071
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Ref: option_mysql_upgrade_user831459
Ref: option_mysql_upgrade_verbose831604
Node: programs-client831690
Node: mysql832432
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Ref: option_mysql_help844882
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Ref: option_mysql_character-sets-dir845973
Ref: option_mysql_column-names846104
Ref: option_mysql_comments846165
Ref: option_mysql_compress846407
Ref: option_mysql_database846537
Ref: option_mysql_debug846650
Ref: option_mysql_debug-info846838
Ref: option_mysql_default-character-set846929
Ref: option_mysql_delimiter847537
Ref: option_mysql_disable-named-commands847650
Ref: option_mysql_execute848027
Ref: option_mysql_force848314
Ref: option_mysql_host848381
Ref: option_mysql_html848476
Ref: option_mysql_ignore-spaces848525
Ref: option_mysql_line-numbers848721
Ref: option_mysql_local-infile848828
Ref: option_mysql_named-commands849187
Ref: option_mysql_no-auto-rehash849486
Ref: option_mysql_no-beep849620
Ref: option_mysql_no-named-commands849682
Ref: option_mysql_no-pager849827
Ref: option_mysql_no-tee849958
Ref: option_mysql_one-database850081
Ref: option_mysql_pager851981
Ref: option_mysql_password852407
Ref: option_mysql_pipe852970
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Ref: option_mysql_prompt853225
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Ref: option_mysql_quick853739
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Ref: option_mysql_reconnect854929
Ref: option_mysql_safe-updates855172
Ref: option_mysql_secure-auth855560
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Ref: option_mysql_skip-column-names856368
Ref: option_mysql_skip-line-numbers856447
Ref: option_mysql_socket856605
Ref: option_mysql_ssl856762
Ref: option_mysql_table856956
Ref: option_mysql_tee857123
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Ref: option_mysql_user857373
Ref: option_mysql_verbose857479
Ref: option_mysql_version857736
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Ref: option_mysql_wait858021
Ref: option_mysql_xml858131
Ref: option_mysql_connect_timeout859741
Ref: option_mysql_max_allowed_packet859850
Ref: option_mysql_max_join_size859979
Ref: option_mysql_select_limit860227
Node: mysql-commands860480
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Node: safe-updates882954
Node: mysql-reconnect884756
Node: mysqladmin886422
Ref: command_mysqladmin_db_name887113
Ref: command_mysqladmin_debug887180
Ref: command_mysqladmin_drop887262
Ref: command_mysqladmin_extended-status887344
Ref: command_mysqladmin_flush-hosts887429
Ref: command_mysqladmin_flush-logs887497
Ref: command_mysqladmin_flush-privileges887539
Ref: command_mysqladmin_flush-status887615
Ref: command_mysqladmin_flush-tables887667
Ref: command_mysqladmin_flush-threads887713
Ref: command_mysqladmin_kill887766
Ref: command_mysqladmin_old-password887899
Ref: command_mysqladmin_password888091
Ref: command_mysqladmin_ping889497
Ref: command_mysqladmin_processlist889860
Ref: command_mysqladmin_reload890175
Ref: command_mysqladmin_refresh890222
Ref: command_mysqladmin_shutdown890292
Ref: command_mysqladmin_start-slave890333
Ref: command_mysqladmin_status890397
Ref: command_mysqladmin_stop-slave890458
Ref: command_mysqladmin_variables890520
Ref: command_mysqladmin_version890599
Ref: option_mysqladmin_help898016
Ref: option_mysqladmin_character-sets-dir898077
Ref: option_mysqladmin_compress898208
Ref: option_mysqladmin_count898338
Ref: option_mysqladmin_debug898474
Ref: option_mysqladmin_default-character-set898672
Ref: option_mysqladmin_force898811
Ref: option_mysqladmin_host898963
Ref: option_mysqladmin_password899058
Ref: option_mysqladmin_pipe899631
Ref: option_mysqladmin_port899790
Ref: option_mysqladmin_protocol899886
Ref: option_mysqladmin_relative900199
Ref: option_mysqladmin_silent900397
Ref: option_mysqladmin_sleep900494
Ref: option_mysqladmin_socket900785
Ref: option_mysqladmin_ssl900942
Ref: option_mysqladmin_user901136
Ref: option_mysqladmin_verbose901242
Ref: option_mysqladmin_version901339
Ref: option_mysqladmin_vertical901408
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Ref: option_mysqladmin_connect_timeout901881
Ref: option_mysqladmin_shutdown_timeout902013
Node: mysqlcheck902252
Ref: option_mysqlcheck_help912689
Ref: option_mysqlcheck_all-databases912750
Ref: option_mysqlcheck_all-in-1912933
Ref: option_mysqlcheck_analyze913129
Ref: option_mysqlcheck_auto-repair913180
Ref: option_mysqlcheck_character-sets-dir913336
Ref: option_mysqlcheck_check913467
Ref: option_mysqlcheck_check-only-changed913556
Ref: option_mysqlcheck_check-upgrade913699
Ref: option_mysqlcheck_compress913935
Ref: option_mysqlcheck_databases914059
Ref: option_mysqlcheck_debug914369
Ref: option_mysqlcheck_default-character-set914540
Ref: option_mysqlcheck_extended914679
Ref: option_mysqlcheck_fast915007
Ref: option_mysqlcheck_force915089
Ref: option_mysqlcheck_host915156
Ref: option_mysqlcheck_medium-check915251
Ref: option_mysqlcheck_optimize915437
Ref: option_mysqlcheck_password915490
Ref: option_mysqlcheck_pipe916063
Ref: option_mysqlcheck_port916222
Ref: option_mysqlcheck_protocol916318
Ref: option_mysqlcheck_quick916631
Ref: option_mysqlcheck_repair916958
Ref: option_mysqlcheck_silent917079
Ref: option_mysqlcheck_socket917149
Ref: option_mysqlcheck_ssl917306
Ref: option_mysqlcheck_tables917500
Ref: option_mysqlcheck_use-frm917641
Ref: option_mysqlcheck_user917837
Ref: option_mysqlcheck_verbose917943
Ref: option_mysqlcheck_version918058
Node: mysqldump918122
Ref: option_mysqldump_help938545
Ref: option_mysqldump_add-drop-database938606
Ref: option_mysqldump_add-drop-table939000
Ref: option_mysqldump_add-locks939145
Ref: option_mysqldump_all-databases939392
Ref: option_mysqldump_allow-keywords939574
Ref: option_mysqldump_character-sets-dir939724
Ref: option_mysqldump_comments939855
Ref: option_mysqldump_compact940098
Ref: option_mysqldump_compatible940702
Ref: option_mysqldump_complete-insert941618
Ref: option_mysqldump_compress941738
Ref: option_mysqldump_create-options941868
Ref: option_mysqldump_databases942001
Ref: option_mysqldump_debug942424
Ref: option_mysqldump_debug-info942627
Ref: option_mysqldump_default-character-set942787
Ref: option_mysqldump_delayed-insert943184
Ref: option_mysqldump_delete-master-logs943328
Ref: option_mysqldump_disable-keys943607
Ref: option_mysqldump_dump-date944023
Ref: option_mysqldump_extended-insert944621
Ref: option_mysqldump_fields944842
Ref: option_mysqldump_first-slave945181
Ref: option_mysqldump_flush-logs945302
Ref: option_mysqldump_flush-privileges945942
Ref: option_mysqldump_force946306
Ref: option_mysqldump_host946901
Ref: option_mysqldump_hex-blob947038
Ref: option_mysqldump_ignore-table947386
Ref: option_mysqldump_insert-ignore947647
Ref: option_mysqldump_lines-terminated-by947779
Ref: option_mysqldump_lock-all-tables947999
Ref: option_mysqldump_lock-tables948256
Ref: option_mysqldump_log-error948938
Ref: option_mysqldump_master-data949114
Ref: option_mysqldump_no-autocommit952452
Ref: option_mysqldump_no-create-db952630
Ref: option_mysqldump_no-create-info952857
Ref: option_mysqldump_no-data952995
Ref: option_mysqldump_no-set-names953306
Ref: option_mysqldump_opt953392
Ref: option_mysqldump_order-by-primary953990
Ref: option_mysqldump_password954285
Ref: option_mysqldump_pipe954856
Ref: option_mysqldump_port955015
Ref: option_mysqldump_protocol955111
Ref: option_mysqldump_quick955424
Ref: option_mysqldump_quote-names955709
Ref: option_mysqldump_result-file956132
Ref: option_mysqldump_routines956498
Ref: option_mysqldump_set-charset957897
Ref: option_mysqldump_single-transaction958089
Ref: option_mysqldump_skip-comments960034
Ref: option_mysqldump_skip-opt960114
Ref: option_mysqldump_socket960184
Ref: option_mysqldump_ssl960341
Ref: option_mysqldump_tab960535
Ref: option_mysqldump_tables961816
Ref: option_mysqldump_triggers961988
Ref: option_mysqldump_tz-utc962231
Ref: option_mysqldump_user962957
Ref: option_mysqldump_verbose963063
Ref: option_mysqldump_version963160
Ref: option_mysqldump_where963229
Ref: option_mysqldump_xml963585
Ref: option_mysqldump_net_buffer_length966772
Node: mysqlimport970025
Ref: option_mysqlimport_help977533
Ref: option_mysqlimport_character-sets-dir977594
Ref: option_mysqlimport_columns977725
Ref: option_mysqlimport_compress977952
Ref: option_mysqlimport_debug978082
Ref: option_mysqlimport_default-character-set978253
Ref: option_mysqlimport_delete978392
Ref: option_mysqlimport_fields978470
Ref: option_mysqlimport_force978758
Ref: option_mysqlimport_host978995
Ref: option_mysqlimport_ignore979132
Ref: option_mysqlimport_ignore-lines979210
Ref: option_mysqlimport_lines-terminated-by979285
Ref: option_mysqlimport_local979725
Ref: option_mysqlimport_lock-tables979801
Ref: option_mysqlimport_low-priority979966
Ref: option_mysqlimport_password980161
Ref: option_mysqlimport_pipe980736
Ref: option_mysqlimport_port980895
Ref: option_mysqlimport_protocol980991
Ref: option_mysqlimport_replace981304
Ref: option_mysqlimport_silent981819
Ref: option_mysqlimport_socket981901
Ref: option_mysqlimport_ssl982058
Ref: option_mysqlimport_user982252
Ref: option_mysqlimport_verbose982358
Ref: option_mysqlimport_version982455
Node: mysqlshow983334
Ref: option_mysqlshow_help989243
Ref: option_mysqlshow_character-sets-dir989304
Ref: option_mysqlshow_compress989435
Ref: option_mysqlshow_count989565
Ref: option_mysqlshow_debug989708
Ref: option_mysqlshow_default-character-set989879
Ref: option_mysqlshow_host990018
Ref: option_mysqlshow_keys990113
Ref: option_mysqlshow_password990161
Ref: option_mysqlshow_pipe990819
Ref: option_mysqlshow_port990978
Ref: option_mysqlshow_protocol991074
Ref: option_mysqlshow_show-table-type991387
Ref: option_mysqlshow_socket991596
Ref: option_mysqlshow_ssl991753
Ref: option_mysqlshow_status991947
Ref: option_mysqlshow_user992021
Ref: option_mysqlshow_verbose992127
Ref: option_mysqlshow_version992312
Node: programs-admin-utils992376
Node: innochecksum994323
Ref: option_innochecksum_count995859
Ref: option_innochecksum_debug995927
Ref: option_innochecksum_end995989
Ref: option_innochecksum_page996036
Ref: option_innochecksum_start996087
Ref: option_innochecksum_verbose996136
Node: myisam-ftdump996210
Ref: option_myisam_ftdump_help998580
Ref: option_myisam_ftdump_count998646
Ref: option_myisam_ftdump_dump998734
Ref: option_myisam_ftdump_length998819
Ref: option_myisam_ftdump_stats998881
Ref: option_myisam_ftdump_verbose999013
Node: myisamchk999100
Node: myisamchk-general-options1013042
Ref: option_myisamchk_help1013507
Ref: option_myisamchk_HELP1013615
Ref: option_myisamchk_debug1013721
Ref: option_myisamchk_silent1013914
Ref: option_myisamchk_verbose1014081
Ref: option_myisamchk_version1014287
Ref: option_myisamchk_wait1014356
Node: myisamchk-check-options1018957
Ref: option_myisamchk_check1019260
Ref: option_myisamchk_check-only-changed1019420
Ref: option_myisamchk_extend-check1019520
Ref: option_myisamchk_fast1020199
Ref: option_myisamchk_force1020280
Ref: option_myisamchk_information1020503
Ref: option_myisamchk_medium-check1020602
Ref: option_myisamchk_read-only1020791
Ref: option_myisamchk_update-state1021087
Node: myisamchk-repair-options1021474
Ref: option_myisamchk_backup1021862
Ref: option_myisamchk_character-sets-dir1021949
Ref: option_myisamchk_correct-checksum1022080
Ref: option_myisamchk_data-file-length1022162
Ref: option_myisamchk_keys-used1022807
Ref: option_myisamchk_no-symlinks1023253
Ref: option_myisamchk_max-record-length1023537
Ref: option_myisamchk_parallel-recover1023690
Ref: option_myisamchk_quick1023894
Ref: option_myisamchk_recover1024148
Ref: option_myisamchk_safe-recover1024719
Ref: option_myisamchk_set-character-set1025315
Ref: option_myisamchk_set-collation1025474
Ref: option_myisamchk_sort-recover1025689
Ref: option_myisamchk_tmpdir1025850
Ref: option_myisamchk_unpack1026354
Node: myisamchk-other-options1026447
Ref: option_myisamchk_analyze1026763
Ref: option_myisamchk_block-search1027182
Ref: option_myisamchk_description1027293
Ref: option_myisamchk_set-auto-increment1027506
Ref: option_myisamchk_sort-index1027875
Ref: option_myisamchk_sort-records1028028
Node: myisamchk-table-info1029018
Node: myisamchk-memory1043315
Node: myisamlog1046364
Ref: option_myisamlog_help1047250
Ref: option_myisamlog_files1047351
Ref: option_myisamlog_information1047413
Ref: option_myisamlog_offset1047473
Ref: option_myisamlog_path1047527
Ref: option_myisamlog_recovery1047578
Ref: option_myisamlog_record-position1047626
Ref: option_myisamlog_update1047721
Ref: option_myisamlog_verbose1047768
Ref: option_myisamlog_write1047926
Ref: option_myisamlog_version1047979
Node: myisampack1048021
Ref: option_myisampack_help1050002
Ref: option_myisampack_backup1050063
Ref: option_myisampack_character-sets-dir1050169
Ref: option_myisampack_debug1050300
Ref: option_myisampack_force1050471
Ref: option_myisampack_join1051104
Ref: option_myisampack_silent1051818
Ref: option_myisampack_test1051898
Ref: option_myisampack_tmpdir1051980
Ref: option_myisampack_verbose1052128
Ref: option_myisampack_version1052256
Ref: option_myisampack_wait1052325
Node: mysqlaccess1063455
Ref: option_mysqlaccess_help1067512
Ref: option_mysqlaccess_brief1067573
Ref: option_mysqlaccess_commit1067650
Ref: option_mysqlaccess_copy1067921
Ref: option_mysqlaccess_db1067997
Ref: option_mysqlaccess_debug1068066
Ref: option_mysqlaccess_host1068149
Ref: option_mysqlaccess_howto1068244
Ref: option_mysqlaccess_old_server1068349
Ref: option_mysqlaccess_password1068507
Ref: option_mysqlaccess_plan1068886
Ref: option_mysqlaccess_preview1068959
Ref: option_mysqlaccess_relnotes1069072
Ref: option_mysqlaccess_rhost1069125
Ref: option_mysqlaccess_rollback1069221
Ref: option_mysqlaccess_spassword1069307
Ref: option_mysqlaccess_superuser1069710
Ref: option_mysqlaccess_table1069818
Ref: option_mysqlaccess_user1069881
Ref: option_mysqlaccess_version1069976
Node: mysqlbinlog1070606
Ref: option_mysqlbinlog_help1079056
Ref: option_mysqlbinlog_character-sets-dir1079117
Ref: option_mysqlbinlog_database1079248
Ref: option_mysqlbinlog_debug1081679
Ref: option_mysqlbinlog_disable-log-bin1081878
Ref: option_mysqlbinlog_force-read1082540
Ref: option_mysqlbinlog_hexdump1082840
Ref: option_mysqlbinlog_host1083072
Ref: option_mysqlbinlog_local-load1083180
Ref: option_mysqlbinlog_offset1083475
Ref: option_mysqlbinlog_password1083546
Ref: option_mysqlbinlog_port1084121
Ref: option_mysqlbinlog_position1084232
Ref: option_mysqlbinlog_protocol1084347
Ref: option_mysqlbinlog_read-from-remote-server1084660
Ref: option_mysqlbinlog_result-file1085124
Ref: option_mysqlbinlog_set-charset1085202
Ref: option_mysqlbinlog_short-form1085414
Ref: option_mysqlbinlog_socket1085611
Ref: option_mysqlbinlog_start-datetime1085768
Ref: option_mysqlbinlog_start-position1086379
Ref: option_mysqlbinlog_stop-datetime1086692
Ref: option_mysqlbinlog_stop-position1087102
Ref: option_mysqlbinlog_to-last-log1087404
Ref: option_mysqlbinlog_user1087731
Ref: option_mysqlbinlog_version1087842
Ref: option_mysqlbinlog_open_files_limit1087988
Node: mysqldumpslow1099511
Ref: option_mysqldumpslow_help1101848
Ref: option_mysqldumpslow_abstract1101903
Ref: option_mysqldumpslow_debug1101978
Ref: option_mysqldumpslow_grep1102026
Ref: option_mysqldumpslow_host1102113
Ref: option_mysqldumpslow_instance1102266
Ref: option_mysqldumpslow_lock1102381
Ref: option_mysqldumpslow_abstract-numbers1102442
Ref: option_mysqldumpslow_reverse1102516
Ref: option_mysqldumpslow_sort1102558
Ref: option_mysqldumpslow_top1103009
Ref: option_mysqldumpslow_verbose1103077
Node: mysqlhotcopy1103677
Ref: option_mysqlhotcopy_help1108108
Ref: option_mysqlhotcopy_addtodest1108169
Ref: option_mysqlhotcopy_allowold1108272
Ref: option_mysqlhotcopy_checkpoint1108374
Ref: option_mysqlhotcopy_chroot1108506
Ref: option_mysqlhotcopy_debug1108715
Ref: option_mysqlhotcopy_dryrun1108759
Ref: option_mysqlhotcopy_flushlog1108829
Ref: option_mysqlhotcopy_host1108895
Ref: option_mysqlhotcopy_keepold1109120
Ref: option_mysqlhotcopy_method1109196
Ref: option_mysqlhotcopy_noindices1109295
Ref: option_mysqlhotcopy_password1109575
Ref: option_mysqlhotcopy_port1109972
Ref: option_mysqlhotcopy_quiet1110085
Ref: option_mysqlhotcopy_record_log_pos1110143
Ref: option_mysqlhotcopy_regexp1110282
Ref: option_mysqlhotcopy_resetmaster1110387
Ref: option_mysqlhotcopy_resetslave1110467
Ref: option_mysqlhotcopy_socket1110554
Ref: option_mysqlhotcopy_suffix1110654
Ref: option_mysqlhotcopy_tmpdir1110731
Ref: option_mysqlhotcopy_user1110808
Node: instance-manager1111142
Node: instance-manager-command-options1114090
Ref: option_mysqlmanager_help1115089
Ref: option_mysqlmanager_angel-pid-file1115150
Ref: option_mysqlmanager_bind-address1115737
Ref: option_mysqlmanager_default-mysqld-path1115797
Ref: option_mysqlmanager_defaults-file1116207
Ref: option_mysqlmanager_install1116753
Ref: option_mysqlmanager_log1116924
Ref: option_mysqlmanager_monitoring-interval1117656
Ref: option_mysqlmanager_passwd1118927
Ref: option_mysqlmanager_password-file1119206
Ref: option_mysqlmanager_pid-file1119560
Ref: option_mysqlmanager_port1119810
Ref: option_mysqlmanager_print-defaults1119973
Ref: option_mysqlmanager_remove1120112
Ref: option_mysqlmanager_run-as-service1120323
Ref: option_mysqlmanager_socket1120547
Ref: option_mysqlmanager_standalone1120736
Ref: option_mysqlmanager_user1120970
Ref: option_mysqlmanager_version1121526
Ref: option_mysqlmanager_wait-timeout1121595
Node: instance-manager-configuration-files1121872
Node: instance-manager-startup-process1125610
Node: instance-manager-security-passwords1129593
Node: instance-manager-security-monitoring1132954
Node: instance-manager-security1134401
Node: instance-manager-commands1135341
Node: mysql-convert-table-format1142820
Ref: option_mysql_convert_table_format_help1143811
Ref: option_mysql_convert_table_format_force1143866
Ref: option_mysql_convert_table_format_host1143920
Ref: option_mysql_convert_table_format_password1143999
Ref: option_mysql_convert_table_format_port1144392
Ref: option_mysql_convert_table_format_socket1144473
Ref: option_mysql_convert_table_format_type1144563
Ref: option_mysql_convert_table_format_user1144726
Ref: option_mysql_convert_table_format_verbose1144816
Ref: option_mysql_convert_table_format_version1144907
Node: mysql-explain-log1144965
Ref: option_mysql_explain_log_help1146061
Ref: option_mysql_explain_log_date1146122
Ref: option_mysql_explain_log_host1146217
Ref: option_mysql_explain_log_password1146312
Ref: option_mysql_explain_log_printerror1146533
Ref: option_mysql_explain_log_socket1146592
Ref: option_mysql_explain_log_user1146749
Node: mysql-find-rows1146850
Ref: option_mysql_find_rows_help1148116
Ref: option_mysql_find_rows_regexp1148188
Ref: option_mysql_find_rows_rows1148260
Ref: option_mysql_find_rows_skip-use-db1148317
Ref: option_mysql_find_rows_start_row1148401
Node: mysql-fix-extensions1148453
Node: mysql-setpermission1149405
Ref: option_mysql_setpermission_help1150664
Ref: option_mysql_setpermission_host1150719
Ref: option_mysql_setpermission_password1150798
Ref: option_mysql_setpermission_port1151191
Ref: option_mysql_setpermission_socket1151272
Ref: option_mysql_setpermission_user1151362
Node: mysql-tableinfo1151447
Ref: option_mysql_tableinfo_help1155573
Ref: option_mysql_tableinfo_clear1155628
Ref: option_mysql_tableinfo_clear-only1155712
Ref: option_mysql_tableinfo_col1155829
Ref: option_mysql_tableinfo_host1155897
Ref: option_mysql_tableinfo_idx1155992
Ref: option_mysql_tableinfo_password1156059
Ref: option_mysql_tableinfo_port1156466
Ref: option_mysql_tableinfo_prefix1156562
Ref: option_mysql_tableinfo_quiet1156658
Ref: option_mysql_tableinfo_socket1156716
Ref: option_mysql_tableinfo_tbl-status1156804
Ref: option_mysql_tableinfo_user1156993
Node: mysql-waitpid1157094
Ref: option_mysql_waitpid_help1158172
Ref: option_mysql_waitpid_verbose1158239
Ref: option_mysql_waitpid_version1158367
Node: mysql-zap1158431
Ref: option_mysql_zap_help1159531
Ref: option_mysql_zap_force1159598
Ref: option_mysql_zap_test1159715
Node: programs-development1159803
Node: msql2mysql1161734
Node: mysql-config1162880
Ref: option_mysql_config_cflags1163335
Ref: option_mysql_config_include1163741
Ref: option_mysql_config_libmysqld-libs1163812
Ref: option_mysql_config_libs1163934
Ref: option_mysql_config_libs_r1164031
Ref: option_mysql_config_port1164142
Ref: option_mysql_config_socket1164228
Ref: option_mysql_config_version1164314
Node: my-print-defaults1165839
Ref: option_my_print_defaults_help1166869
Ref: option_my_print_defaults_config-file1166930
Ref: option_my_print_defaults_debug1167053
Ref: option_my_print_defaults_defaults-extra-file1167254
Ref: option_my_print_defaults_defaults-group-suffix1167448
Ref: option_my_print_defaults_no-defaults1167605
Ref: option_my_print_defaults_verbose1167664
Ref: option_my_print_defaults_version1167761
Node: resolve-stack-dump1167825
Ref: option_resolve_stack_dump_help1168674
Ref: option_resolve_stack_dump_numeric-dump-file1168735
Ref: option_resolve_stack_dump_symbols-file1168838
Ref: option_resolve_stack_dump_version1168922
Node: programs-miscellaneous1168986
Node: perror1169384
Ref: option_perror_help1170642
Ref: option_perror_ndb1170719
Ref: option_perror_silent1170796
Ref: option_perror_verbose1170869
Ref: option_perror_version1170979
Node: replace-utility1171043
Ref: option_replace_help1172579
Ref: option_replace_debug1172636
Ref: option_replace_silent1172685
Ref: option_replace_verbose1172762
Ref: option_replace_version1172846
Node: resolveip1172897
Ref: option_resolveip_help1173393
Ref: option_resolveip_silent1173470
Ref: option_resolveip_version1173534
Node: server-administration1173598
Node: mysqld-server1174926
Node: mysqld-option-tables1176122
Node: server-options1241579
Ref: option_mysqld_help1244839
Ref: option_mysqld_allow-suspicious-udfs1245178
Ref: option_mysqld_ansi1246109
Ref: option_mysqld_basedir1246533
Ref: option_mysqld_big-tables1247326
Ref: option_mysqld_bind-address1248297
Ref: option_mysqld_bootstrap1249243
Ref: option_mysqld_character-sets-dir1249759
Ref: option_mysqld_character-set-client-handshake1250551
Ref: option_mysqld_character-set-filesystem1251277
Ref: option_mysqld_character-set-server1252195
Ref: option_mysqld_chroot1253157
Ref: option_mysqld_collation-server1253969
Ref: option_mysqld_console1254749
Ref: option_mysqld_core-file1255172
Ref: option_mysqld_datadir1256594
Ref: option_mysqld_debug1257309
Ref: option_mysqld_default-character-set1258660
Ref: option_mysqld_default-collation1259483
Ref: option_mysqld_default-storage-engine1260153
Ref: option_mysqld_default-table-type1260678
Ref: option_mysqld_default-time-zone1261347
Ref: option_mysqld_delay-key-write1262016
Ref: option_mysqld_des-key-file1263502
Ref: option_mysqld_enable-named-pipe1263858
Ref: option_mysqld_enable-pstack1264402
Ref: option_mysqld_engine-condition-pushdown1265047
Ref: option_mysqld_exit-info1266224
Ref: option_mysqld_external-locking1266886
Ref: option_mysqld_flush1268012
Ref: option_mysqld_gdb1268786
Ref: option_mysqld_init-file1269438
Ref: option_mysqld_innodb-safe-binlog1270376
Ref: option_mysqld_install1271444
Ref: option_mysqld_install-manual1271854
Ref: option_mysqld_language1272327
Ref: option_mysqld_large-pages1273361
Ref: option_mysqld_log1274729
Ref: option_mysqld_log-error1275723
Ref: option_mysqld_log-isam1276587
Ref: option_mysqld_log-long-format1277092
Ref: option_mysqld_log-queries-not-using-indexes1277920
Ref: option_mysqld_log-short-format1279044
Ref: option_mysqld_log-slow-admin-statements1279657
Ref: option_mysqld_log-slow-queries1280324
Ref: option_mysqld_log-tc1281342
Ref: option_mysqld_log-tc-size1282181
Ref: option_mysqld_log-warnings1283179
Ref: option_mysqld_low-priority-updates1285057
Ref: option_mysqld_memlock1286318
Ref: option_mysqld_myisam-block-size1288061
Ref: option_mysqld_myisam-recover1288689
Ref: option_mysqld_old-passwords1291228
Ref: option_mysqld_old-style-user-limits1292132
Ref: option_mysqld_one-thread1292906
Ref: option_mysqld_open-files-limit1293328
Ref: option_mysqld_pid-file1294786
Ref: option_mysqld_port1295732
Ref: option_mysqld_port-open-timeout1296577
Ref: option_mysqld_remove1297470
Ref: option_mysqld_safe-mode1297814
Ref: option_mysqld_safe-show-database1298124
Ref: option_mysqld_safe-user-create1299012
Ref: option_mysqld_secure-auth1300106
Ref: option_mysqld_secure-file-priv1300854
Ref: option_mysqld_shared-memory1301813
Ref: option_mysqld_shared-memory-base-name1301942
Ref: option_mysqld_skip-bdb1302161
Ref: option_mysqld_skip-concurrent-insert1302337
Ref: option_mysqld_skip-external-locking1302575
Ref: option_mysqld_skip-grant-tables1302927
Ref: option_mysqld_skip-host-cache1303691
Ref: option_mysqld_skip-merge1304169
Ref: option_mysqld_skip-name-resolve1304574
Ref: option_mysqld_skip-networking1304831
Ref: option_mysqld_standalone1305368
Ref: option_mysqld_symbolic-links1305660
Ref: option_mysqld_skip-safemalloc1306695
Ref: option_mysqld_skip-show-database1307214
Ref: option_mysqld_skip-stack-trace1308190
Ref: option_mysqld_skip-thread-priority1308694
Ref: option_mysqld_socket1309430
Ref: option_mysqld_sql-mode1310590
Ref: option_mysqld_sysdate-is-now1312535
Ref: option_mysqld_tc-heuristic-recover1313553
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Node: condition-pushdown-optimization2077229
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Node: multiple-column-indexes2175694
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Node: concurrent-inserts2247784
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Node: optimizing-database-structure2255339
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Node: creating-many-tables2266239
Node: internal-temporary-tables2266921
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Node: general-thread-states2322318
Node: delayed-insert-thread-states2334958
Node: query-cache-thread-states2338015
Node: master-thread-states2338979
Node: slave-io-thread-states2340297
Node: slave-sql-thread-states2343602
Node: slave-connection-thread-states2344946
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Ref: date-and-time-string-numeric-literals2357716
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Node: boolean-literals2365301
Node: bit-field-literals2365664
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Node: multi-byte-characters2547079
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Node: floating-point-types2640046
Node: bit-type2641962
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Node: datetime2656127
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Ref: operator_less-than-or-equal2766267
Ref: operator_less-than2766363
Ref: operator_greater-than-or-equal2766446
Ref: operator_greater-than2766543
Ref: operator_is2766629
Ref: operator_is-not2766915
Ref: operator_is-null2767226
Ref: operator_is-not-null2769043
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Ref: operator_not-between2770507
Ref: function_coalesce2770605
Ref: function_greatest2770880
Ref: function_in2771448
Ref: function_not-in2773029
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Ref: function_interval2773629
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Node: logical-operators2775773
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Ref: operator_or2777831
Ref: operator_xor2778418
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Ref: operator_assign-equal2781523
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Ref: function_ifnull2786552
Ref: function_nullif2787913
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Ref: function_bin2794094
Ref: function_bit-length2794379
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Ref: function_char-length2796750
Ref: function_character-length2797040
Ref: function_concat2797132
Ref: function_concat-ws2798112
Ref: function_elt2798895
Ref: function_export-set2799292
Ref: function_field2800198
Ref: function_find-in-set2800914
Ref: function_format2801639
Ref: function_hex2802133
Ref: function_insert2802894
Ref: function_instr2803628
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Ref: function_left2804188
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Ref: function_load-file2804732
Ref: function_locate2805654
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Ref: function_lpad2807347
Ref: function_ltrim2807699
Ref: function_make-set2807901
Ref: function_mid2808586
Ref: function_oct2808680
Ref: function_octet-length2808962
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Ref: function_position2809551
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Ref: function_rtrim2811895
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Ref: operator_sounds-like2813662
Ref: function_space2813756
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Ref: function_substring2814054
Ref: function_substring-index2815481
Ref: function_trim2816174
Ref: function_ucase2816883
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Node: string-comparison-functions2819387
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Ref: operator_not-like2825516
Ref: function_strcmp2826582
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Ref: operator_regexp2829589
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Ref: operator_minus2848550
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Ref: operator_div2849575
Ref: operator_mod2849864
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Ref: function_acos2853040
Ref: function_asin2853379
Ref: function_atan2854198
Ref: function_atan22854438
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Ref: function_ceiling2854907
Ref: function_conv2855297
Ref: function_cos2856135
Ref: function_cot2856271
Ref: function_crc322856451
Ref: function_degrees2856854
Ref: function_exp2857071
Ref: function_floor2857464
Ref: function_ln2858335
Ref: function_log2858735
Ref: function_log22859584
Ref: function_log102859929
Ref: function_mod2860231
Ref: function_pi2860863
Ref: function_pow2861193
Ref: function_power2861385
Ref: function_radians2861442
Ref: function_rand2861650
Ref: function_round2864820
Ref: function_sign2867632
Ref: function_sin2867944
Ref: function_sqrt2868160
Ref: function_tan2868423
Ref: function_truncate2868652
Node: date-and-time-functions2869357
Ref: function_adddate2876055
Ref: function_addtime2876812
Ref: function_convert-tz2877224
Ref: function_curdate2878414
Ref: function_current-date2878738
Ref: function_curtime2878850
Ref: function_current-time2879234
Ref: function_current-timestamp2879346
Ref: function_date2879479
Ref: function_datediff2879657
Ref: function_date-add2880108
Ref: function_date-format2887633
Ref: function_date-sub2891401
Ref: function_day2891488
Ref: function_dayname2891554
Ref: function_dayofmonth2891858
Ref: function_dayofweek2892124
Ref: function_dayofyear2892376
Ref: function_extract2892546
Ref: function_from-days2893182
Ref: function_from-unixtime2893537
Ref: function_get-format2894868
Ref: function_hour2896721
Ref: function_last-day2897114
Ref: function_localtime2897625
Ref: function_localtimestamp2897721
Ref: function_makedate2897837
Ref: function_maketime2898283
Ref: function_microsecond2898486
Ref: function_minute2898814
Ref: function_month2898976
Ref: function_monthname2899247
Ref: function_now2899558
Ref: function_period-add2901712
Ref: function_period-diff2901985
Ref: function_quarter2902280
Ref: function_second2902447
Ref: function_sec-to-time2902598
Ref: function_str-to-date2903068
Ref: function_subdate2905855
Ref: function_subtime2906621
Ref: function_sysdate2907066
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Ref: function_timediff2909434
Ref: function_timestamp2909960
Ref: function_timestampadd2910480
Ref: function_timestampdiff2911464
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Ref: function_time-to-sec2913151
Ref: function_to-days2913385
Ref: function_unix-timestamp2915658
Ref: function_utc-date2918519
Ref: function_utc-time2918818
Ref: function_utc-timestamp2919123
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Ref: function_weekday2922098
Ref: function_weekofyear2922366
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Ref: function_yearweek2922833
Node: mysql-calendar2923404
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Ref: function_match2925958
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Ref: function_cast2973319
Ref: function_convert2973529
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Ref: function_bit-count2981731
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Ref: function_aes-decrypt2986158
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Ref: function_compress2987860
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Ref: function_des-encrypt2990429
Ref: function_encode2992494
Ref: function_encrypt2992806
Ref: function_md52993648
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Ref: function_password2994699
Ref: function_sha12996001
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Ref: function_uncompressed-length2997334
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Ref: function_benchmark2999189
Ref: function_charset3001632
Ref: function_coercibility3001938
Ref: function_collation3003371
Ref: function_connection-id3003617
Ref: function_current-user3003874
Ref: function_database3005428
Ref: function_found-rows3005884
Ref: function_last-insert-id3009883
Ref: function_row-count3017625
Ref: function_schema3019689
Ref: function_session-user3019792
Ref: function_system-user3019866
Ref: function_user3019938
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Ref: function_inet-aton3025379
Ref: function_inet-ntoa3026431
Ref: function_is-free-lock3026759
Ref: function_is-used-lock3027029
Ref: function_master-pos-wait3027244
Ref: function_name-const3028229
Ref: function_release-lock3028934
Ref: function_sleep3029461
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Node: group-by-functions3033152
Ref: function_avg3036122
Ref: function_bit-and3036511
Ref: function_bit-or3036866
Ref: function_bit-xor3037094
Ref: function_count3037324
Ref: function_count-distinct3038582
Ref: function_group-concat3039097
Ref: function_max3041812
Ref: function_min3042688
Ref: function_std3043564
Ref: function_stddev3043836
Ref: function_stddev-pop3044130
Ref: function_stddev-samp3044461
Ref: function_sum3044688
Ref: function_var-pop3044951
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Ref: function_variance3045590
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Node: group-by-hidden-columns3053816
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Node: creating-a-spatially-enabled-mysql-database3083710
Node: mysql-spatial-datatypes3084448
Node: creating-spatial-values3085436
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Ref: function_geomcollfromtext3086766
Ref: function_geomfromtext3086941
Ref: function_linefromtext3087097
Ref: function_mlinefromtext3087247
Ref: function_mpointfromtext3087408
Ref: function_mpolyfromtext3087560
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Ref: function_geomfromwkb3089596
Ref: function_linefromwkb3089750
Ref: function_mlinefromwkb3089898
Ref: function_mpointfromwkb3090057
Ref: function_mpolyfromwkb3090207
Ref: function_pointfromwkb3090360
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Ref: function_bdmpolyfromwkb3090874
Ref: function_bdpolyfromwkb3091069
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Ref: function_geometrycollection3092567
Ref: function_linestring3092647
Ref: function_multilinestring3092852
Ref: function_multipoint3092988
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Ref: function_point3093240
Ref: function_polygon3093310
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Node: populating-spatial-columns3094626
Node: fetching-spatial-data3097574
Node: spatial-analysis-functions3098499
Node: functions-to-convert-geometries-between-formats3099930
Ref: function_asbinary3100336
Ref: function_astext3100523
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Node: general-geometry-property-functions3102638
Ref: function_dimension3102996
Ref: function_envelope3103570
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Ref: function_numinteriorrings3114241
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Ref: function_centroid3115706
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Node: spatial-operators3118638
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Ref: function_convexhull3119190
Ref: function_difference3119300
Ref: function_intersection3119432
Ref: function_symdifference3119569
Ref: function_union3119714
Node: functions-for-testing-spatial-relations-between-geometric-objects3119831
Node: relations-on-geometry-mbr3120552
Ref: function_mbrcontains3121152
Ref: function_mbrdisjoint3121858
Ref: function_mbrequal3122029
Ref: function_mbrintersects3122178
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Ref: function_crosses3124599
Ref: function_disjoint3125226
Ref: function_equals3125352
Ref: function_intersects3125445
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Node: creating-spatial-indexes3127868
Node: using-a-spatial-index3130395
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Node: precision-math-numbers3140024
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Node: sql-syntax-data-definition3165069
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Ref: isolevel_read-committed3528457
Ref: isolevel_repeatable-read3529678
Ref: isolevel_serializable3530895
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Node: stored-program-variables3590959
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Node: loop-statement3603402
Node: repeat-statement3604585
Node: return3605805
Node: while-statement3606436
Node: cursors3607227
Node: close3608760
Node: declare-cursor3609197
Node: fetch3610306
Node: open3611136
Node: condition-handling3611371
Node: declare-condition3612499
Node: declare-handler3614465
Node: sql-syntax-server-administration3621659
Node: account-management-sql3622244
Node: create-user3623376
Node: drop-user3625843
Node: grant3628466
Ref: grant-privileges3631525
Ref: grant-global-privileges3636452
Ref: grant-database-privileges3637276
Ref: grant-table-privileges3638061
Ref: grant-column-privileges3638739
Ref: grant-routine-privileges3639227
Ref: grant-accounts-passwords3641426
Ref: grant-other-characteristics3646243
Ref: grant-mysql-vs-standard-sql3654476
Node: rename-user3656619
Node: revoke3658050
Node: set-password3660276
Node: table-maintenance-sql3663042
Node: analyze-table3663655
Node: backup-table3665483
Node: check-table3666968
Node: checksum-table3674672
Node: optimize-table3676312
Node: repair-table3679224
Node: restore-table3685322
Node: plugin-sql3686689
Node: create-function-udf3687049
Node: drop-function-udf3690211
Node: set-option3691167
Node: show3701728
Node: show-binary-logs3706590
Node: show-binlog-events3707390
Node: show-character-set3708651
Node: show-collation3709948
Node: show-columns3712790
Node: show-create-database3717842
Node: show-create-function3718983
Node: show-create-procedure3719364
Node: show-create-table3720826
Node: show-create-view3721711
Node: show-databases3724249
Node: show-engine3725485
Node: show-engines3729872
Node: show-errors3734640
Node: show-function-code3735833
Node: show-function-status3736267
Node: show-grants3736667
Node: show-index3738689
Node: show-innodb-status3741050
Node: show-logs3741443
Node: show-master-status3741744
Node: show-mutex-status3742484
Node: show-open-tables3745597
Node: show-privileges3747269
Node: show-procedure-code3748716
Node: show-procedure-status3751153
Node: show-processlist3752485
Node: show-profile3757399
Node: show-profiles3757852
Node: show-slave-hosts3764689
Node: show-slave-status3766204
Node: show-status3778041
Node: show-table-status3781514
Node: show-tables3786271
Node: show-triggers3787455
Node: show-variables3789940
Node: show-warnings3794963
Node: other-administrative-sql3800700
Node: cache-index3801156
Node: flush3803606
Node: kill3811433
Node: load-index3814496
Node: reset3816467
Node: sql-syntax-utility3817396
Node: describe3817767
Node: explain3819886
Node: help3821147
Node: use3827149
Node: storage-engines3828154
Node: myisam-storage-engine3838133
Node: myisam-start3845431
Node: key-space3850828
Node: myisam-table-formats3851959
Node: static-format3853155
Node: dynamic-format3855841
Node: compressed-format3859057
Node: myisam-table-problems3861002
Node: corrupted-myisam-tables3861562
Node: myisam-table-close3863697
Node: innodb-storage-engine3866379
Node: innodb-contact-information3870922
Node: innodb-configuration3871630
Node: innodb-multiple-tablespaces3884478
Node: innodb-raw-devices3888707
Node: innodb-init3891042
Node: error-creating-innodb3894381
Node: innodb-parameters3895927
Ref: option_mysqld_innodb3904643
Ref: option_mysqld_innodb-status-file3905032
Ref: sysvar_innodb_adaptive_hash_index3905618
Ref: sysvar_innodb_additional_mem_pool_size3906658
Ref: sysvar_innodb_autoextend_increment3908012
Ref: sysvar_innodb_buffer_pool_awe_mem_mb3909317
Ref: sysvar_innodb_buffer_pool_size3911029
Ref: sysvar_innodb_checksums3912301
Ref: sysvar_innodb_commit_concurrency3913423
Ref: sysvar_innodb_concurrency_tickets3914475
Ref: sysvar_innodb_data_file_path3916068
Ref: sysvar_innodb_data_home_dir3917527
Ref: sysvar_innodb_doublewrite3918604
Ref: sysvar_innodb_fast_shutdown3919677
Ref: sysvar_innodb_file_io_threads3921133
Ref: sysvar_innodb_file_per_table3922190
Ref: sysvar_innodb_flush_log_at_trx_commit3923126
Ref: sysvar_innodb_flush_method3926406
Ref: sysvar_innodb_force_recovery3928258
Ref: sysvar_innodb_lock_wait_timeout3929557
Ref: sysvar_innodb_locks_unsafe_for_binlog3931556
Ref: sysvar_innodb_log_arch_dir3939807
Ref: sysvar_innodb_log_archive3939938
Ref: sysvar_innodb_log_buffer_size3940243
Ref: sysvar_innodb_log_file_size3941468
Ref: sysvar_innodb_log_files_in_group3942762
Ref: sysvar_innodb_log_group_home_dir3943723
Ref: sysvar_innodb_max_dirty_pages_pct3944671
Ref: sysvar_innodb_max_purge_lag3945732
Ref: sysvar_innodb_mirrored_log_groups3948059
Ref: sysvar_innodb_open_files3948202
Ref: sysvar_innodb_rollback_on_timeout3949327
Ref: sysvar_innodb_support_xa3951534
Ref: sysvar_innodb_sync_spin_loops3953601
Ref: sysvar_innodb_table_locks3954312
Ref: sysvar_innodb_thread_concurrency3955417
Ref: sysvar_innodb_thread_sleep_delay3957812
Ref: sysvar_innodb_use_legacy_cardinality_algorithm3959777
Node: using-innodb-tables3963233
Node: innodb-transactions-with-different-apis3965391
Node: converting-tables-to-innodb3967521
Node: innodb-auto-increment-handling3970593
Node: innodb-foreign-key-constraints3974431
Node: innodb-and-mysql-replication3991003
Node: innodb-data-log-reconfiguration3996185
Node: innodb-backup4000115
Node: innodb-recovery4006411
Node: forcing-innodb-recovery4007800
Node: innodb-checkpoints4011026
Node: innodb-migration4012817
Node: innodb-transaction-model4014447
Node: innodb-lock-modes4018474
Node: innodb-consistent-read4023574
Node: innodb-locking-reads4028576
Node: innodb-record-level-locks4033379
Node: innodb-next-key-locking4037782
Node: innodb-locks-set4041089
Node: innodb-implicit-commit4050963
Node: innodb-deadlock-detection4051813
Node: innodb-deadlocks4053147
Node: innodb-multi-versioning4056864
Node: innodb-table-and-index4060418
Node: innodb-index-types4061459
Node: innodb-physical-structure4063299
Node: innodb-insert-buffering4064521
Node: innodb-adaptive-hash4066505
Node: innodb-physical-record4067638
Node: innodb-disk-management4073471
Node: innodb-disk-io4073888
Node: innodb-file-space4075376
Node: innodb-file-defragmenting4078968
Node: innodb-error-handling4080703
Node: innodb-error-codes4083919
Node: operating-system-error-codes4085576
Ref: operating-system-error-codes-linux4086047
Ref: operating-system-error-codes-windows4087719
Node: innodb-tuning-troubleshooting4091620
Node: innodb-tuning4092196
Node: innodb-monitors4101014
Node: innodb-standard-monitor4107000
Node: innodb-tablespace-monitor4120077
Node: innodb-table-monitor4125897
Node: innodb-troubleshooting4135463
Node: innodb-troubleshooting-datadict4137381
Node: innodb-restrictions4141945
Node: merge-storage-engine4153229
Node: merge-table-advantages4160535
Node: merge-table-problems4164315
Node: memory-storage-engine4172145
Node: bdb-storage-engine4181562
Node: bdb-portability4182910
Node: bdb-install4184084
Node: bdb-start4184828
Ref: option_mysqld_bdb-home4187227
Ref: option_mysqld_bdb-lock-detect4187364
Ref: option_mysqld_bdb-logdir4187515
Ref: option_mysqld_bdb-no-recover4187583
Ref: option_mysqld_bdb-no-sync4187657
Ref: option_mysqld_bdb-shared-data4187846
Ref: option_mysqld_bdb-tmpdir4187982
Ref: option_mysqld_sync-bdb-logs4188110
Node: bdb-characteristics4189392
Node: bdb-restrictions4195441
Node: bdb-errors4196750
Node: example-storage-engine4198065
Node: federated-storage-engine4199444
Node: federated-description4201061
Node: federated-use4203775
Node: federated-limitations4207690
Node: archive-storage-engine4212274
Node: csv-storage-engine4215898
Node: blackhole-storage-engine4217860
Node: ha-overview4222669
Ref: figure_ha-cost-vs-nines4225674
Ref: figure_ha-application-architecture-mapping4225976
Ref: ha-availability-comparison4226154
Node: ha-ovm-template4230493
Node: ha-drbd4232985
Ref: ha-drbd-overview4234539
Node: ha-drbd-install4235558
Node: ha-drbd-install-os4239464
Node: ha-drbd-install-drbd4246580
Node: ha-drbd-install-drbd-primary4249469
Node: ha-drbd-install-drbd-secondary4254714
Node: ha-drbd-install-drbd-using4256813
Node: ha-drbd-install-drbd-management4259194
Node: ha-drbd-install-drbd-othercfg4260950
Node: ha-drbd-install-mysql4262741
Node: ha-drbd-performance4265254
Ref: ha-drbd-performance-sepinterface4266199
Node: ha-drbd-performance-bonded4266788
Node: ha-drbd-performance-syncrate4272620
Node: ha-heartbeat4276192
Ref: ha-heartbeat-overview4278307
Node: ha-heartbeat-config4279527
Node: ha-heartbeat-drbd4284018
Node: ha-heartbeat-drbd-dopd4288520
Node: ha-heartbeat-errors4291146
Node: ha-vm4292453
Node: ha-vm-aws-setup4295857
Node: ha-vm-aws-instance4299808
Node: ha-vm-aws-deploy4301768
Node: ha-zfs-replication4305944
Node: ha-zfs-config4310771
Node: ha-zfs-mysql4314133
Node: ha-zfs-mysql-recovery4315808
Node: ha-memcached4317613
Ref: ha-memcached-fig-overview4319698
Node: ha-memcached-install4321912
Node: ha-memcached-using4325054
Node: ha-memcached-using-deployment4335297
Node: ha-memcached-using-namespaces4337621
Node: ha-memcached-using-expiry4339055
Node: ha-memcached-using-hashtypes4341308
Ref: ha-memcached-using-hashtypes-fig-selection4343274
Ref: ha-memcached-using-hashtypes-fig-addselect4346458
Node: ha-memcached-using-dtrace4349692
Node: ha-memcached-using-memory4357816
Ref: ha-memcached-fig-slabs4360057
Node: ha-memcached-using-threads4361938
Node: ha-memcached-using-logs4363743
Node: ha-memcached-interfaces4372974
Ref: ha-memcached-fig-basicflow4374881
Node: ha-memcached-interfaces-libmemcached4377856
Node: ha-memcached-interfaces-libmemcached-base4381917
Node: ha-memcached-interfaces-libmemcached-servers4383089
Node: ha-memcached-interfaces-libmemcached-set4386428
Node: ha-memcached-interfaces-libmemcached-get4391508
Node: ha-memcached-interfaces-libmemcached-behaviors4396100
Node: ha-memcached-interfaces-libmemcached-utilities4400142
Node: ha-memcached-interfaces-perl4401989
Node: ha-memcached-interfaces-python4408708
Node: ha-memcached-interfaces-php4414831
Node: ha-memcached-interfaces-ruby4422146
Node: ha-memcached-interfaces-java4424939
Node: ha-memcached-interfaces-mysqludf4428724
Node: ha-memcached-interfaces-protocol4435586
Node: ha-memcached-interfaces-protocol-tcp4436063
Ref: ha-memcached-interfaces-protocol-responses4445346
Node: ha-memcached-stats4446848
Node: ha-memcached-stats-general4452707
Node: ha-memcached-stats-slabs4458754
Node: ha-memcached-stats-items4462944
Node: ha-memcached-stats-sizes4465467
Node: ha-memcached-stats-detail4466792
Node: ha-memcached-stats-memcached-tool4468983
Node: ha-memcached-faq4474852
Ref: qandaitem-15-6-5-1-14479022
Ref: qandaitem-15-6-5-1-24479359
Ref: qandaitem-15-6-5-1-34479586
Ref: qandaitem-15-6-5-1-44479781
Ref: qandaitem-15-6-5-1-54480420
Ref: qandaitem-15-6-5-1-64480690
Ref: qandaitem-15-6-5-1-74481400
Ref: qandaitem-15-6-5-1-84482206
Ref: qandaitem-15-6-5-1-94482874
Ref: qandaitem-15-6-5-1-104483152
Ref: qandaitem-15-6-5-1-114483897
Ref: qandaitem-15-6-5-1-124484212
Ref: qandaitem-15-6-5-1-134484589
Ref: qandaitem-15-6-5-1-144484925
Ref: qandaitem-15-6-5-1-154485286
Ref: qandaitem-15-6-5-1-164486277
Ref: qandaitem-15-6-5-1-174486850
Ref: qandaitem-15-6-5-1-184487339
Ref: qandaitem-15-6-5-1-194487917
Ref: qandaitem-15-6-5-1-204487979
Ref: qandaitem-15-6-5-1-214488586
Ref: qandaitem-15-6-5-1-224489336
Ref: qandaitem-15-6-5-1-234489576
Ref: qandaitem-15-6-5-1-244490144
Ref: qandaitem-15-6-5-1-254491143
Ref: qandaitem-15-6-5-1-264491694
Ref: qandaitem-15-6-5-1-274492393
Ref: qandaitem-15-6-5-1-284492622
Ref: qandaitem-15-6-5-1-294494206
Ref: qandaitem-15-6-5-1-304494538
Node: mysql-proxy4496180
Node: mysql-proxy-platforms4498767
Node: mysql-proxy-install4499807
Node: mysql-proxy-install-binary4500905
Node: mysql-proxy-install-source4502763
Node: mysql-proxy-install-cvs4504338
Node: mysql-proxy-configuration-windows4506205
Node: mysql-proxy-configuration4508332
Ref: option_mysql-proxy_help4515292
Ref: option_mysql-proxy_help-admin4515545
Ref: option_mysql-proxy_help-all4515777
Ref: option_mysql-proxy_help-proxy4515989
Ref: option_mysql-proxy_admin-address4516221
Ref: option_mysql-proxy_admin-lua-script4516783
Ref: option_mysql-proxy_admin-password4517349
Ref: option_mysql-proxy_admin-username4518008
Ref: option_mysql-proxy_basedir4518709
Ref: option_mysql-proxy_daemon4519408
Ref: option_mysql-proxy_defaults-file4519622
Ref: option_mysql-proxy_event-threads4519922
Ref: option_mysql-proxy_keepalive4520435
Ref: option_mysql-proxy_log-backtrace-on-crash4521020
Ref: option_mysql-proxy_log-file4521365
Ref: option_mysql-proxy_log-level4521952
Ref: option_mysql-proxy_log-use-syslog4522764
Ref: option_mysql-proxy_lua-cpath4523021
Ref: option_mysql-proxy_lua-path4523548
Ref: option_mysql-proxy_max-open-files4524036
Ref: option_mysql-proxy_no-proxy4524603
Ref: option_mysql-proxy_plugin-dir4524818
Ref: option_mysql-proxy_plugins4525346
Ref: option_mysql-proxy_proxy-address4525781
Ref: option_mysql-proxy_proxy-read-only-backend-addresses4526463
Ref: option_mysql-proxy_proxy-backend-addresses4528152
Ref: option_mysql-proxy_proxy-pool-no-change-user4529717
Ref: option_mysql-proxy_proxy-skip-profiling4530144
Ref: option_mysql-proxy_proxy-fix-bug-253714530481
Ref: option_mysql-proxy_proxy-lua-script4531181
Ref: option_mysql-proxy_pid-file4532142
Ref: option_mysql-proxy_user4532633
Ref: option_mysql-proxy_version4533073
Node: mysql-proxy-scripting4534658
Node: mysql-proxy-scripting-injection4539497
Node: mysql-proxy-scripting-structures4542342
Ref: mysql-proxy-scripting-structures-proxy4542995
Ref: mysql-proxy-scripting-structures-connection4544052
Ref: mysql-proxy-scripting-structures-backends4546329
Ref: mysql-proxy-scripting-structures-queries4547627
Ref: mysql-proxy-scripting-structures-response4550225
Ref: mysql-proxy-scripting-structures-resultset4553147
Ref: mysql-proxy-scripting-structures-return-states4555082
Ref: mysql-proxy-scripting-structures-packet-states4555905
Ref: mysql-proxy-scripting-structures-backend-states4556239
Ref: mysql-proxy-scripting-structures-command-constants4556853
Ref: mysql-proxy-scripting-structures-type-constants4558458
Node: mysql-proxy-scripting-connect-server4559692
Node: mysql-proxy-scripting-read-handshake4561194
Node: mysql-proxy-scripting-read-auth4563338
Node: mysql-proxy-scripting-read-auth-result4564780
Node: mysql-proxy-scripting-read-query4566416
Node: mysql-proxy-scripting-read-query-result4569830
Node: mysql-proxy-using4574520
Node: mysql-proxy-using-admin4576979
Node: mysql-proxy-faq4589664
Ref: qandaitem-15-7-6-1-14594498
Ref: qandaitem-15-7-6-1-24594937
Ref: qandaitem-15-7-6-1-34595148
Ref: qandaitem-15-7-6-1-44595335
Ref: qandaitem-15-7-6-1-54595615
Ref: qandaitem-15-7-6-1-64595950
Ref: qandaitem-15-7-6-1-74596199
Ref: qandaitem-15-7-6-1-84596439
Ref: qandaitem-15-7-6-1-94596755
Ref: qandaitem-15-7-6-1-104596929
Ref: qandaitem-15-7-6-1-114597159
Ref: qandaitem-15-7-6-1-124597276
Ref: qandaitem-15-7-6-1-134597526
Ref: qandaitem-15-7-6-1-144597844
Ref: qandaitem-15-7-6-1-154598044
Ref: qandaitem-15-7-6-1-164598319
Ref: qandaitem-15-7-6-1-174598543
Ref: qandaitem-15-7-6-1-184598790
Ref: qandaitem-15-7-6-1-194599010
Ref: qandaitem-15-7-6-1-204599241
Ref: qandaitem-15-7-6-1-214599446
Ref: qandaitem-15-7-6-1-224599623
Ref: qandaitem-15-7-6-1-234599816
Ref: qandaitem-15-7-6-1-244600161
Ref: qandaitem-15-7-6-1-254600334
Ref: qandaitem-15-7-6-1-264600701
Ref: qandaitem-15-7-6-1-274601035
Ref: qandaitem-15-7-6-1-284601280
Ref: qandaitem-15-7-6-1-294601585
Ref: qandaitem-15-7-6-1-304601847
Ref: qandaitem-15-7-6-1-314602029
Ref: qandaitem-15-7-6-1-324602312
Ref: qandaitem-15-7-6-1-334602437
Ref: qandaitem-15-7-6-1-344602747
Ref: qandaitem-15-7-6-1-354602972
Ref: qandaitem-15-7-6-1-364603263
Ref: qandaitem-15-7-6-1-374603478
Node: replication4603774
Node: replication-configuration4607468
Node: replication-howto4610784
Node: replication-howto-masterbaseconfig4615135
Node: replication-howto-slavebaseconfig4617184
Node: replication-howto-repuser4618719
Node: replication-howto-masterstatus4620446
Node: replication-howto-mysqldump4624252
Node: replication-howto-rawdata4626560
Node: replication-howto-newservers4630328
Node: replication-howto-existingdata4632238
Node: replication-howto-additionalslaves4636850
Node: replication-howto-slaveinit4640808
Node: replication-options4642026
Ref: option_mysqld_server-id4643086
Node: replication-options-table4644521
Node: replication-options-master4652769
Ref: sysvar_auto_increment_increment4653761
Ref: sysvar_auto_increment_offset4662165
Node: replication-options-slave4663408
Ref: replication-optvars-slaves4667757
Ref: option_mysqld_abort-slave-event-count4668186
Ref: option_mysqld_disconnect-slave-event-count4669475
Ref: option_mysqld_log-slave-updates4670063
Ref: option_mysqld_master-connect-retry4673264
Ref: option_mysqld_master-host4674282
Ref: option_mysqld_master-info-file4674916
Ref: option_mysqld_master-password4675668
Ref: option_mysqld_master-port4676351
Ref: option_mysqld_master-retry-count4677029
Ref: option_mysqld_master-ssl4678531
Ref: option_mysqld_master-user4679117
Ref: option_mysqld_max-relay-log-size4679914
Ref: option_mysqld_read-only4680104
Ref: option_mysqld_relay-log4680439
Ref: option_mysqld_relay-log-index4682488
Ref: option_mysqld_relay-log-info-file4684214
Ref: option_mysqld_relay-log-purge4685077
Ref: option_mysqld_relay-log-space-limit4685351
Ref: option_mysqld_replicate-do-db4686568
Ref: option_mysqld_replicate-ignore-db4688767
Ref: option_mysqld_replicate-do-table4690579
Ref: option_mysqld_replicate-ignore-table4691604
Ref: option_mysqld_replicate-rewrite-db4692711
Ref: option_mysqld_replicate-same-server-id4694098
Ref: option_mysqld_replicate-wild-do-table4695322
Ref: option_mysqld_replicate-wild-ignore-table4697732
Ref: option_mysqld_report-host4698932
Ref: option_mysqld_report-password4700261
Ref: option_mysqld_report-port4701544
Ref: option_mysqld_report-user4702641
Ref: option_mysqld_show-slave-auth-info4703889
Ref: option_mysqld_skip-slave-start4704557
Ref: optvar_slave_compressed_protocol4705163
Ref: option_mysqld_slave-load-tmpdir4706061
Ref: option_mysqld_slave-net-timeout4707288
Ref: option_mysqld_slave-skip-errors4708530
Ref: replication-sysvars-slaves4710513
Ref: sysvar_init_slave4710841
Ref: sysvar_relay_log_index4711943
Ref: sysvar_relay_log_info_file4712797
Ref: sysvar_rpl_recovery_rank4713656
Ref: sysvar_slave_compressed_protocol4713743
Ref: sysvar_slave_load_tmpdir4714575
Ref: sysvar_slave_net_timeout4715436
Ref: sysvar_slave_skip_errors4716404
Ref: sysvar_slave_transaction_retries4717172
Ref: sysvar_sql_slave_skip_counter4719104
Node: replication-options-binary-log4719929
Ref: replication-optvars-binlog4720571
Ref: option_mysqld_log-bin4720788
Ref: option_mysqld_log-bin-index4722048
Ref: option_mysqld_log-bin-trust-function-creators4722737
Ref: option_mysqld_log-bin-trust-routine-creators4723920
Ref: option_mysqld_binlog-do-db4725682
Ref: option_mysqld_binlog-ignore-db4728508
Ref: option_mysqld_max-binlog-dump-events4730387
Ref: option_mysqld_sporadic-binlog-dump-fail4730953
Ref: replication-sysvars-binlog4731522
Ref: sysvar_log_slave_updates4731840
Ref: sysvar_max_binlog_cache_size4732121
Ref: sysvar_max_binlog_size4733072
Ref: sysvar_sync_binlog4734482
Node: replication-administration4736528
Node: replication-administration-status4737138
Node: replication-administration-pausing4743397
Node: replication-implementation4745487
Node: replication-implementation-details4748144
Node: slave-logs4753810
Node: slave-logs-relaylog4755050
Node: slave-logs-status4758449
Node: replication-rules4763799
Node: replication-rules-db-options4766888
Node: replication-rules-table-options4770292
Node: replication-rules-examples4773095
Node: replication-solutions4775564
Node: replication-solutions-backups4777797
Node: replication-solutions-backups-mysqldump4779433
Node: replication-solutions-backups-rawdata4782140
Node: replication-solutions-diffengines4784947
Node: replication-solutions-scaleout4789062
Ref: figure_replication-scaleout4790255
Node: replication-solutions-partitioning4792240
Ref: figure_replication-multi-db4792856
Node: replication-solutions-performance4794656
Ref: figure_replication-performance4795801
Node: replication-solutions-switch4798057
Ref: figure_replication-redundancy-before4799666
Ref: figure_replication-redundancy-after4802833
Node: replication-solutions-ssl4804175
Node: replication-notes4808297
Node: replication-features4808863
Node: replication-features-auto-increment4812569
Node: replication-features-charset4815796
Node: replication-features-create-select4817959
Node: replication-features-drop-if-exists4819094
Node: replication-features-directory4820024
Node: replication-features-floatvalues4821019
Node: replication-features-flush4821895
Node: replication-features-functions4823335
Node: replication-features-limit4829135
Node: replication-features-load4829662
Node: replication-features-logging4830826
Node: replication-features-repair-table4831264
Node: replication-features-shutdowns4832227
Node: replication-features-memory4835063
Node: replication-features-temptables4836536
Node: replication-features-mysqldb4838500
Node: replication-features-userprivs4839107
Node: replication-features-optimizer4840039
Node: replication-features-reserved-words4840827
Node: replication-features-slaveerrors4842933
Node: replication-features-sql-mode4845282
Node: replication-features-timeout4845901
Node: replication-features-timestamp4846783
Node: replication-features-timezone4847716
Node: replication-features-transactions4848759
Node: replication-features-triggers4852406
Node: replication-features-views4853600
Node: replication-features-variables4854231
Node: replication-compatibility4857283
Node: replication-upgrade4861209
Node: replication-faq4864932
Ref: qandaitem-16-4-4-1-14866502
Ref: qandaitem-16-4-4-1-24868837
Ref: qandaitem-16-4-4-1-34869682
Ref: qandaitem-16-4-4-1-44870033
Ref: qandaitem-16-4-4-1-54871200
Ref: qandaitem-16-4-4-1-64872203
Ref: qandaitem-16-4-4-1-74873589
Ref: qandaitem-16-4-4-1-84874201
Ref: qandaitem-16-4-4-1-94876235
Ref: qandaitem-16-4-4-1-104879274
Ref: qandaitem-16-4-4-1-114879506
Ref: qandaitem-16-4-4-1-124879662
Node: replication-problems4879829
Node: replication-bugs4884995
Node: mysql-cluster4887670
Node: mysql-cluster-overview4890909
Node: mysql-cluster-basics4895372
Node: mysql-cluster-nodes-groups4904019
Node: mysql-cluster-overview-requirements4909340
Ref: mysql-cluster-network-latency-issues4912495
Node: mysql-cluster-development4915874
Node: mysql-cluster-development-5-04916730
Node: mysql-cluster-limitations4919561
Node: mysql-cluster-limitations-syntax4921895
Node: mysql-cluster-limitations-limits4925731
Node: mysql-cluster-limitations-transactions4930119
Node: mysql-cluster-limitations-error-handling4936867
Node: mysql-cluster-limitations-database-objects4937924
Node: mysql-cluster-limitations-unsupported4939983
Node: mysql-cluster-limitations-performance4941683
Node: mysql-cluster-limitations-exclusive-to-cluster4942890
Node: mysql-cluster-limitations-multiple-nodes4946052
Node: mysql-cluster-limitations-resolved4950567
Node: mysql-cluster-installation4952691
Node: mysql-cluster-install-linux4959070
Node: mysql-cluster-install-linux-binary4960998
Node: mysql-cluster-install-linux-rpm4966688
Node: mysql-cluster-install-linux-source4972515
Node: mysql-cluster-install-configuration4976147
Node: mysql-cluster-install-first-start4981931
Node: mysql-cluster-install-example-data4984831
Node: mysql-cluster-install-shutdown-restart4994952
Node: mysql-cluster-upgrade-downgrade4996854
Node: mysql-cluster-configuration4998897
Node: mysql-cluster-quick5001070
Node: mysql-cluster-config-file5006638
Node: mysql-cluster-config-example5009188
Ref: mysql-cluster-config-ini-sections5014813
Node: mysql-cluster-connectstring5017158
Node: mysql-cluster-computer-definition5019990
Ref: ndbparam-computer-id5020451
Ref: ndbparam-computer-hostname5021210
Node: mysql-cluster-mgm-definition5021616
Ref: ndbparam-mgmd-id5022290
Ref: ndbparam-mgmd-nodeid5023170
Ref: ndbparam-mgmd-executeoncomputer5023856
Ref: ndbparam-mgmd-portnumber5024351
Ref: ndbparam-mgmd-hostname5024878
Ref: ndbparam-mgmd-logdestination5025462
Ref: ndbparam-mgmd-arbitrationrank5027600
Ref: ndbparam-mgmd-arbitrationdelay5028797
Ref: ndbparam-mgmd-datadir5029437
Node: mysql-cluster-ndbd-definition5030770
Ref: mysql-cluster-identifying-data-nodes5032223
Ref: ndbparam-ndbd-id5032372
Ref: ndbparam-ndbd-nodeid5033261
Ref: ndbparam-ndbd-executeoncomputer5033947
Ref: ndbparam-ndbd-hostname5034417
Ref: ndbparam-ndbd-serverport5034998
Ref: ndbparam-ndbd-noofreplicas5036533
Ref: ndbparam-ndbd-datadir5039956
Ref: ndbparam-ndbd-filesystempath5040529
Ref: ndbparam-ndbd-backupdatadir5041563
Ref: mysql-cluster-data-memory-index-memory-string-memory5042462
Ref: ndbparam-ndbd-datamemory5042841
Ref: ndbparam-ndbd-indexmemory5048114
Ref: ndbparam-ndbd-stringmemory5049187
Ref: mysql-cluster-transaction-parameters5053900
Ref: ndbparam-ndbd-maxnoofconcurrenttransactions5054565
Ref: ndbparam-ndbd-maxnoofconcurrentoperations5056568
Ref: ndbparam-ndbd-maxnooflocaloperations5059581
Ref: mysql-cluster-transaction-temporary-storage5060414
Ref: ndbparam-ndbd-maxnoofconcurrentindexoperations5061034
Ref: ndbparam-ndbd-maxnooffiredtriggers5062335
Ref: ndbparam-ndbd-transactionbuffermemory5063631
Ref: mysql-cluster-scans-and-buffering5064912
Ref: ndbparam-ndbd-maxnoofconcurrentscans5065405
Ref: ndbparam-ndbd-maxnooflocalscans5067044
Ref: ndbparam-ndbd-batchsizeperlocalscan5067755
Ref: ndbparam-ndbd-longmessagebuffer5068411
Ref: mysql-cluster-logging-and-checkpointing5069359
Ref: ndbparam-ndbd-nooffragmentlogfiles5069463
Ref: ndbparam-ndbd-maxnoofopenfiles5071908
Ref: ndbparam-ndbd-maxnoofsavedmessages5072233
Ref: mysql-cluster-metadata-objects5072888
Ref: ndbparam-ndbd-maxnoofattributes5073244
Ref: ndbparam-ndbd-maxnooftables5075799
Ref: ndbparam-ndbd-maxnooforderedindexes5077496
Ref: ndbparam-ndbd-maxnoofuniquehashindexes5078601
Ref: ndbparam-ndbd-maxnooftriggers5079593
Ref: ndbparam-ndbd-maxnoofindexes5080451
Ref: mysql-cluster-boolean-parameters5080833
Ref: ndbparam-ndbd-lockpagesinmainmemory5081080
Ref: ndbparam-ndbd-stoponerror5083124
Ref: ndbparam-ndbd-diskless5083714
Ref: ndbparam-ndbd-restartonerrorinsert5084892
Ref: mysql-cluster-timeouts-intervals-disk-paging5085535
Ref: ndbparam-ndbd-timebetweenwatchdogcheck5085829
Ref: ndbparam-ndbd-startpartialtimeout5086850
Ref: ndbparam-ndbd-startpartitionedtimeout5087772
Ref: ndbparam-ndbd-startfailuretimeout5088655
Ref: ndbparam-ndbd-heartbeatintervaldbdb5089699
Ref: ndbparam-ndbd-heartbeatintervaldbapi5091015
Ref: ndbparam-ndbd-timebetweenlocalcheckpoints5092286
Ref: ndbparam-ndbd-timebetweenglobalcheckpoints5093807
Ref: ndbparam-ndbd-timebetweeninactivetransactionabortcheck5095378
Ref: ndbparam-ndbd-transactioninactivetimeout5096159
Ref: ndbparam-ndbd-transactiondeadlockdetectiontimeout5097009
Ref: ndbparam-ndbd-noofdiskpagestodiskafterrestarttup5098704
Ref: ndbparam-ndbd-noofdiskpagestodiskafterrestartacc5100552
Ref: ndbparam-ndbd-noofdiskpagestodiskduringrestarttup5101286
Ref: ndbparam-ndbd-noofdiskpagestodiskduringrestartacc5102331
Ref: ndbparam-ndbd-arbitrationtimeout5103180
Ref: mysql-cluster-buffering-and-logging5103859
Ref: ndbparam-ndbd-undoindexbuffer5104453
Ref: ndbparam-ndbd-undodatabuffer5106581
Ref: ndbparam-ndbd-redobuffer5108250
Ref: mysql-cluster-controlling-log-messages5109375
Ref: ndbparam-ndbd-loglevelstartup5110160
Ref: ndbparam-ndbd-loglevelshutdown5110684
Ref: ndbparam-ndbd-loglevelstatistic5111219
Ref: ndbparam-ndbd-loglevelcheckpoint5111847
Ref: ndbparam-ndbd-loglevelnoderestart5112422
Ref: ndbparam-ndbd-loglevelconnection5112939
Ref: ndbparam-ndbd-loglevelerror5113476
Ref: ndbparam-ndbd-loglevelcongestion5114105
Ref: ndbparam-ndbd-loglevelinfo5114749
Ref: mysql-cluster-backup-parameters5115287
Ref: ndbparam-ndbd-backupdatabuffersize5115427
Ref: ndbparam-ndbd-backuplogbuffersize5116466
Ref: ndbparam-ndbd-backupmemory5118098
Ref: ndbparam-ndbd-backupwritesize5118840
Ref: ndbparam-ndbd-backupmaxwritesize5119408
Node: mysql-cluster-api-definition5120730
Ref: ndbparam-api-id5121957
Ref: ndbparam-api-nodeid5122849
Ref: ndbparam-api-executeoncomputer5123535
Ref: ndbparam-api-hostname5124038
Ref: ndbparam-api-arbitrationrank5125043
Ref: ndbparam-api-arbitrationdelay5125971
Ref: ndbparam-api-batchbytesize5126634
Ref: ndbparam-api-batchsize5127454
Ref: ndbparam-api-maxscanbatchsize5127661
Node: mysql-cluster-tcp-definition5129735
Ref: ndbparam-tcp-nodeid15131272
Ref: ndbparam-tcp-nodeid25131618
Ref: ndbparam-tcp-hostname15132246
Ref: ndbparam-tcp-hostname25132595
Ref: ndbparam-tcp-sendbuffermemory5133197
Ref: ndbparam-tcp-sendsignalid5134163
Ref: ndbparam-tcp-checksum5134946
Ref: ndbparam-tcp-portnumber5135692
Ref: ndbparam-tcp-receivebuffermemory5135880
Node: mysql-cluster-tcp-definition-direct5136615
Node: mysql-cluster-shm-definition5138510
Ref: ndbparam-shm-nodeid15139792
Ref: ndbparam-shm-nodeid25140138
Ref: ndbparam-shm-hostname15140643
Ref: ndbparam-shm-hostname25140992
Ref: ndbparam-shm-shmkey5141594
Ref: ndbparam-shm-shmsize5142190
Ref: ndbparam-shm-sendsignalid5142807
Ref: ndbparam-shm-checksum5143496
Ref: ndbparam-shm-signum5144220
Node: mysql-cluster-sci-definition5145270
Ref: ndbparam-sci-nodeid15146669
Ref: ndbparam-sci-nodeid25147015
Ref: ndbparam-sci-host1sciid05147520
Ref: ndbparam-sci-host1sciid15148018
Ref: ndbparam-sci-host2sciid05148660
Ref: ndbparam-sci-host2sciid15149160
Ref: ndbparam-sci-hostname15149697
Ref: ndbparam-sci-hostname25150046
Ref: ndbparam-sci-sharedbuffersize5150648
Ref: ndbparam-sci-sendlimit5151504
Ref: ndbparam-sci-sendsignalid5152231
Ref: ndbparam-sci-checksum5152866
Node: mysql-cluster-config-lcp-params5153580
Node: mysql-cluster-params-overview5159719
Node: mysql-cluster-params-ndbd5163137
Node: mysql-cluster-params-mgmd5170489
Node: mysql-cluster-params-api5173324
Node: mysql-cluster-params-other5176160
Node: mysql-cluster-options-variables5180714
Node: mysql-cluster-option-tables5181732
Node: mysql-cluster-program-options-mysqld5184243
Ref: option_mysqld_ndb-connectstring5185439
Ref: option_mysqld_ndb-mgmd-host5186077
Ref: option_mysqld_ndbcluster5186825
Ref: option_mysqld_ndb-nodeid5187753
Ref: option_mysqld_skip-ndbcluster5189654
Node: mysql-cluster-system-variables5190243
Ref: sysvar_have_ndbcluster5190854
Ref: sysvar_multi_range_count5191499
Ref: sysvar_ndb_autoincrement_prefetch_sz5192868
Ref: sysvar_ndb_cache_check_time5194828
Ref: sysvar_ndb_force_send5196097
Ref: sysvar_ndb_index_stat_cache_entries5196928
Ref: sysvar_ndb_index_stat_enable5197766
Ref: sysvar_ndb_index_stat_update_freq5198318
Ref: sysvar_ndb_optimized_node_selection5199053
Ref: sysvar_ndb_report_thresh_binlog_epoch_slip5200084
Ref: sysvar_ndb_report_thresh_binlog_mem_usage5201040
Ref: sysvar_ndb_use_exact_count5201951
Ref: sysvar_ndb_use_transactions5202713
Node: mysql-cluster-status-variables5203504
Ref: statvar_Handler_discover5204032
Ref: statvar_Ndb_cluster_node_id5204334
Ref: statvar_Ndb_config_from_host5204578
Ref: statvar_Ndb_config_from_port5204989
Ref: statvar_Ndb_number_of_data_nodes5205416
Node: mysql-cluster-interconnects5205753
Node: mysql-cluster-sci-sockets5208387
Node: mysql-cluster-interconnects-performance5210438
Node: mysql-cluster-programs5214671
Node: mysql-cluster-programs-mysqld5217863
Node: mysql-cluster-programs-ndbd5222673
Ref: option_ndbd_bind-address5225383
Ref: option_ndbd_daemon5226010
Ref: option_ndbd_initial5226615
Ref: option_ndbd_initial-start5228923
Ref: option_ndbd_nowait-nodes5229964
Ref: option_ndbd_nodaemon5231601
Ref: option_ndbd_foreground5232415
Ref: option_ndbd_nostart5232958
Node: mysql-cluster-programs-ndb-mgmd5239518
Ref: option_ndb_mgmd_no-nodeid-checks5241630
Ref: option_ndb_mgmd_config-file5242055
Ref: option_ndb_mgmd_mycnf5243060
Ref: option_ndb_mgmd_daemon5243461
Ref: option_ndb_mgmd_interactive5243991
Ref: option_ndb_mgmd_nodaemon5244651
Ref: option_ndb_mgmd_print-full-config5245330
Node: mysql-cluster-programs-ndb-mgm5248060
Ref: option_ndb_mgm_execute5249853
Ref: option_ndb_mgm_try-reconnect5250860
Node: mysql-cluster-programs-ndb-config5251695
Ref: option_ndb_config_usage5253539
Ref: option_ndb_config_version5253898
Ref: option_ndb_config_ndb-connectstring5254209
Ref: option_ndb_config_config-file5254649
Ref: option_ndb_config_mycnf5255394
Ref: option_ndb_config_query5255795
Ref: option_ndb_config_host5256895
Ref: option_ndb_config_id5258160
Ref: option_ndb_config_nodeid5258177
Ref: option_ndb_config_nodes5258313
Ref: option_ndb_config_connections5259034
Ref: option_ndb_config_type5259215
Ref: option_ndb_config_fields5259868
Ref: option_ndb_config_rows5260556
Node: mysql-cluster-programs-ndb-cpcd5263326
Node: mysql-cluster-programs-ndb-delete-all5264079
Node: mysql-cluster-programs-ndb-desc5265152
Ref: option_ndb_desc_extra-partition-info5267350
Node: mysql-cluster-programs-ndb-drop-index5267449
Node: mysql-cluster-programs-ndb-drop-table5269820
Node: mysql-cluster-programs-ndb-error-reporter5270640
Ref: option_ndb_error_reporter_fs5272490
Node: mysql-cluster-programs-ndb-print-backup-file5273114
Node: mysql-cluster-programs-ndb-print-schema-file5274734
Node: mysql-cluster-programs-ndb-print-sys-file5276126
Node: mysql-cluster-programs-ndb-restore5277792
Ref: option_ndb_restore_connect5282042
Ref: option_ndb_restore_nodeid5283176
Ref: option_ndb_restore_backupid5283733
Ref: option_ndb_restore_backup_path5284268
Ref: option_ndb_restore_dont_ignore_systab_05287137
Ref: option_ndb_restore_parallelism5287553
Ref: option_ndb_restore_restore_data5287778
Ref: option_ndb_restore_restore_meta5287919
Ref: option_ndb_restore_print_metadata5288049
Ref: option_ndb_restore_print_log5288181
Ref: option_ndb_restore_print5288317
Ref: option_ndb_restore_print_data5288540
Ref: option_ndb_restore_tab5289140
Ref: option_ndb_restore_fields-enclosed-by5289602
Ref: option_ndb_restore_fields-optionally-enclosed-by5290163
Ref: option_ndb_restore_fields-terminated-by5290875
Ref: option_ndb_restore_hex5291488
Ref: option_ndb_restore_lines-terminated-by5291742
Ref: option_ndb_restore_append5292352
Ref: option_ndb_restore_verbose5292828
Node: mysql-cluster-programs-ndb-select-all5293686
Node: mysql-cluster-programs-ndb-select-count5297704
Node: mysql-cluster-programs-ndb-show-tables5298805
Ref: option_ndb_show_tables_database5300497
Ref: option_ndb_show_tables_loops5300595
Ref: option_ndb_show_tables_parsable5300812
Ref: option_ndb_show_tables_show-temp-status5300962
Ref: option_ndb_show_tables_type5301056
Ref: option_ndb_show_tables_unqualified5301405
Node: mysql-cluster-programs-ndb-size-pl5301880
Ref: option_ndb_size_pl_options5303963
Node: mysql-cluster-programs-ndb-waiter5305008
Ref: mysql-cluster-programs-ndb-waiter-additional-options5307547
Ref: option_ndb_waiter_no-contact5307575
Ref: option_ndb_waiter_not-started5307798
Ref: option_ndb_waiter_timeout5308017
Ref: option_ndb_waiter_single-user5308226
Node: mysql-cluster-program-options-common5310010
Ref: option_ndb_common_help5312562
Ref: option_ndb_common_ndb-connectstring5312873
Ref: option_ndb_common_ndb-mgmd-host5313761
Ref: option_ndb_common_character-sets-dir5314509
Ref: option_ndb_common_connect-string5315011
Ref: option_ndb_common_core-file5315316
Ref: option_ndb_common_debug5316375
Ref: option_ndb_common_ndb-nodeid5316960
Ref: option_ndb_common_ndb-optimized-node-selection5317620
Ref: option_ndb_common_version5318107
Ref: option_ndb_common_ndb-shm5318741
Node: mysql-cluster-management5319402
Node: mysql-cluster-start-phases5321690
Node: mysql-cluster-mgm-client-commands5328927
Node: mysql-cluster-backup5333404
Node: mysql-cluster-backup-concepts5334800
Node: mysql-cluster-backup-using-management-client5336651
Node: mysql-cluster-backup-configuration5344256
Node: mysql-cluster-backup-troubleshooting5345421
Node: mysql-cluster-rolling-restart5346585
Node: mysql-cluster-event-reports5350816
Node: mysql-cluster-logging-management-commands5355989
Node: mysql-cluster-log-events5359519
Node: mysql-cluster-log-statistics5370519
Node: mysql-cluster-logs-ndb-messages5379226
Node: mysql-cluster-logs-cluster-log5379860
Node: mysql-cluster-ndb-transporter-errors5425983
Node: mysql-cluster-single-user-mode5432086
Node: mysql-cluster-sql-statements5434223
Node: mysql-cluster-security5438084
Node: mysql-cluster-security-networking-issues5438966
Node: mysql-cluster-security-mysql-privileges5448894
Node: mysql-cluster-security-mysql-security-procedures5456449
Node: stored-programs-views5460640
Node: stored-programs-defining5462821
Node: stored-routines5465843
Node: stored-routines-syntax5469051
Node: stored-routines-privileges5472430
Node: stored-routines-metadata5474085
Node: stored-routines-last-insert-id5475339
Node: triggers5476443
Node: trigger-syntax5478502
Node: trigger-metadata5486511
Node: views5486920
Node: view-syntax5488174
Node: view-algorithms5489525
Node: view-updatability5493166
Node: view-metadata5499196
Node: stored-programs-security5499593
Node: stored-programs-logging5505620
Node: information-schema5536047
Node: character-sets-table5545389
Node: collations-table5546279
Node: collation-character-set-applicability-table5547921
Node: columns-table5548722
Node: column-privileges-table5551356
Node: key-column-usage-table5553100
Node: profiling-table5555851
Node: routines-table5558613
Node: schemata-table5560777
Node: schema-privileges-table5561777
Node: statistics-table5562895
Node: tables-table5564887
Node: table-constraints-table5567747
Node: table-privileges-table5569100
Node: triggers-table5570346
Node: user-privileges-table5575360
Node: views-table5576387
Node: other-information-schema-tables5580449
Node: extended-show5580924
Node: connectors-apis5586591
Ref: connectors-apis-summary5591873
Ref: connectors-apis-versions5596932
Node: connector-odbc5597928
Node: connector-odbc-versions5600846
Node: connector-odbc-introduction5603574
Node: connector-odbc-general-information5604487
Node: connector-odbc-architecture5605349
Node: connector-odbc-driver-manager5609167
Node: connector-odbc-installation5610887
Node: connector-odbc-installation-binary-windows5614626
Node: connector-odbc-installation-binary-windows-installer5616641
Node: connector-odbc-installation-binary-windows-dll5618875
Node: connector-odbc-installation-binary-unix5622328
Node: connector-odbc-installation-binary-unix-tarball5623236
Node: connector-odbc-installation-binary-unix-rpm5624323
Node: connector-odbc-installation-binary-macosx5625659
Node: connector-odbc-installation-source-windows5630214
Node: connector-odbc-installation-source-windows-5-1-building5631903
Node: connector-odbc-installation-source-windows-3-51-building5633528
Node: connector-odbc-installation-source-unix5636083
Node: connector-odbc-installation-source-unix-cmake-options5639364
Node: connector-odbc-installation-source-unix-configure-options5640661
Node: connector-odbc-installation-source-unix-otheroptions5643319
Node: connector-odbc-installation-source-unix-building5645490
Node: connector-odbc-installation-source-unix-shared-libraries5646069
Node: connector-odbc-installation-source-unix-installing5648615
Node: connector-odbc-installation-source-unix-testing5649613
Node: connector-odbc-installation-source-unix-macosx5650456
Node: connector-odbc-installation-source-unix-hpux5652429
Node: connector-odbc-installation-source-unix-aix5653787
Node: connector-odbc-installation-source-development5654594
Node: connector-odbc-configuration5657196
Node: connector-odbc-configuration-dsn5658642
Node: connector-odbc-configuration-connection-parameters5660071
Node: connector-odbc-configuration-dsn-windows5675852
Node: connector-odbc-configuration-dsn-windows-3-515679719
Node: connector-odbc-configuration-dsn-windows-3-51-command-line5683200
Node: connector-odbc-configuration-dsn-windows-5-15683766
Node: connector-odbc-configuration-dsn-windows-5-1-command-line5687293
Node: connector-odbc-configuration-dsn-windows-problems5687884
Node: connector-odbc-configuration-dsn-macosx5689199
Node: connector-odbc-configuration-dsn-unix5692110
Node: connector-odbc-configuration-connection-without-dsn5694089
Node: connector-odbc-configuration-connection-pooling5695614
Node: connector-odbc-configuration-trace5696385
Node: connector-odbc-configuration-trace-windows5697212
Node: connector-odbc-configuration-trace-macosx5698288
Node: connector-odbc-configuration-trace-unix5698987
Node: connector-odbc-configuration-trace-log5700026
Node: connector-odbc-examples5701124
Node: connector-odbc-examples-overview5702268
Node: connector-odbc-examples-walkthrough5703026
Node: connector-odbc-examples-tools5705145
Node: connector-odbc-examples-tools-with-access5707701
Node: connector-odbc-examples-tools-with-access-export5708564
Node: connector-odbc-examples-tools-with-access-import5710372
Node: connector-odbc-examples-tools-with-access-linked-tables5711606
Node: connector-odbc-examples-tools-with-wordexcel5715086
Node: connector-odbc-examples-tools-with-crystalreports5718297
Node: connector-odbc-examples-programming5723020
Node: connector-odbc-examples-programming-vb5723839
Node: connector-odbc-examples-programming-vb-ado5724564
Node: connector-odbc-examples-programming-vb-dao5727491
Node: connector-odbc-examples-programming-vb-rdo5729920
Node: connector-odbc-examples-programming-net5732106
Node: connector-odbc-examples-programming-net-csharp5732666
Node: connector-odbc-examples-programming-net-vb5738614
Node: connector-odbc-reference5742597
Node: connector-odbc-reference-api5743271
Node: connector-odbc-reference-datatypes5754784
Node: connector-odbc-reference-errorcodes5757764
Node: connector-odbc-usagenotes5760998
Node: connector-odbc-usagenotes-functionality5761672
Node: connector-odbc-usagenotes-functionality-last-insert-id5762433
Node: connector-odbc-usagenotes-functionality-dynamic-cursor5764040
Node: connector-odbc-usagenotes-functionality-performance5764729
Node: connector-odbc-usagenotes-functionality-query-timeout5766324
Node: connector-odbc-usagenotes-apptips5766849
Node: connector-odbc-usagenotes-apptips-microsoft5768355
Node: connector-odbc-usagenotes-apptips-microsoft-access5769605
Node: connector-odbc-usagenotes-apptips-microsoft-excel5774110
Node: connector-odbc-usagenotes-apptips-microsoft-visualbasic5775319
Node: connector-odbc-usagenotes-apptips-microsoft-visualinterdev5776090
Node: connector-odbc-usagenotes-apptips-microsoft-visualobjects5776684
Node: connector-odbc-usagenotes-apptips-microsoft-ado5777057
Node: connector-odbc-usagenotes-apptips-microsoft-asp5778658
Node: connector-odbc-usagenotes-apptips-microsoft-vb-asp5779581
Node: connector-odbc-usagenotes-apptips-borland5780315
Node: connector-odbc-usagenotes-apptips-borland-builder5781224
Node: connector-odbc-usagenotes-apptips-borland-delphi5781783
Node: connector-odbc-usagenotes-apptips-borland-cppbuilder5783772
Node: connector-odbc-usagenotes-apptips-coldfusion5784295
Node: connector-odbc-usagenotes-apptips-openoffice5785716
Node: connector-odbc-usagenotes-apptips-sambarserver5786261
Node: connector-odbc-usagenotes-apptips-datajunction5786723
Node: connector-odbc-usagenotes-apptips-vision5787233
Node: connector-odbc-errors5787561
Ref: qandaitem-20-1-7-3-1-15791908
Ref: qandaitem-20-1-7-3-1-25792871
Ref: qandaitem-20-1-7-3-1-35793220
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Ref: qandaitem-20-1-7-3-1-115797999
Ref: qandaitem-20-1-7-3-1-125798722
Ref: qandaitem-20-1-7-3-1-135799029
Ref: qandaitem-20-1-7-3-1-145799408
Ref: qandaitem-20-1-7-3-1-155799807
Ref: qandaitem-20-1-7-3-1-165800218
Ref: qandaitem-20-1-7-3-1-175800767
Ref: qandaitem-20-1-7-3-1-185801119
Ref: qandaitem-20-1-7-3-1-195801519
Ref: qandaitem-20-1-7-3-1-205802076
Ref: qandaitem-20-1-7-3-1-215802484
Ref: qandaitem-20-1-7-3-1-225803039
Ref: qandaitem-20-1-7-3-1-235803337
Ref: qandaitem-20-1-7-3-1-245803907
Node: connector-odbc-support5804286
Node: connector-odbc-support-community5805088
Node: connector-odbc-support-bug-report5806004
Node: connector-odbc-support-patch-submission5808516
Node: connector-odbc-support-changehistory5808934
Node: connector-odbc-support-credits5809321
Node: connector-net5809672
Node: connector-net-versions5812617
Node: connector-net-installation5817356
Node: connector-net-installation-windows5818177
Node: connector-net-installation-binary-windows-installer5818932
Node: connector-net-installation-binary-windows-zip5823229
Node: connector-net-installation-unix5825585
Node: connector-net-installation-source5827756
Node: connector-net-visual-studio5829961
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Ref: connector-net-visual-studio-add-connection5833824
Ref: connector-net-visual-studio-choose-data-source5834127
Ref: connector-net-visual-studio-add-connection-dialog5834461
Ref: connector-net-visual-studio-new-data-connection5835053
Node: connector-net-visual-studio-editing-tables5835668
Ref: connector-net-visual-studio-editing-new-table5836997
Ref: connector-net-visual-studio-choose-table-name5838075
Ref: connector-net-visual-studio-newly-created-table5838173
Ref: connector-net-visual-studio-table-desginer-menu-item5838344
Node: connector-net-visual-studio-editing-tables-column-editor5838388
Node: connector-net-visual-studio-editing-tables-indexes5839707
Ref: connector-net-visual-studio-indexes-dialog5840284
Node: connector-net-visual-studio-editing-tables-foreign-keys5840607
Ref: connector-net-visual-studio-foreign-key-relationships5841585
Node: connector-net-visual-studio-editing-tables-column-details5841637
Node: connector-net-visual-studio-editing-tables-table-properties5842214
Ref: connector-net-visual-studio-table-properties-menu5842644
Ref: connector-net-visual-studio-selecting-table-properties5843010
Node: connector-net-visual-studio-editing-views5843046
Ref: connector-net-visual-studio-views-edit-sql5843520
Ref: connector-net-visual-studio-views-sql-added5843599
Ref: connector-net-visual-studio-views-sql-saved5844427
Node: connector-net-visual-studio-editing-stored-procedures-and-functions5844461
Ref: connector-net-visual-studio-stored-procedure-edit5845018
Ref: connector-net-visual-studio-stored-procedure-saved5846534
Node: connector-net-visual-studio-editing-triggers5846580
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Node: connector-net-visual-studio-cloning-database-objects5849651
Node: connector-net-visual-studio-dropping-database-objects5850657
Node: connector-net-visual-studio-entity-framework5851315
Node: connector-net-website-config5853066
Ref: connector-net-website-config-tool5853865
Ref: connector-net-website-config-tool-membership5854014
Ref: connector-net-website-config-tool-string-editor5854414
Ref: connector-net-website-config-tool-options5855407
Ref: connector-net-website-config-tool-roles5855640
Ref: connector-net-website-config-tool-profiles5855865
Ref: connector-net-website-config-tool-session-state5856056
Ref: connector-net-website-config-tool-tables5856639
Node: connector-net-sql-editor5856700
Ref: connector-net-sql-editor-new-file-dialog5857126
Ref: connector-net-sql-editor-query5857905
Node: connector-net-ddl-t4-ef5858063
Ref: connector-net-ddl-t4-ef-properties5858714
Ref: connector-net-ddl-t4-ef-generate5859007
Node: connector-net-tutorials5859075
Node: connector-net-tutorials-intro5860227
Node: connector-net-tutorials-connection5861933
Node: connector-net-tutorials-sql-command5864254
Node: connector-net-tutorials-data-adapter5870202
Ref: connector-net-tutorials-15877262
Node: connector-net-tutorials-parameters5877308
Node: connector-net-tutorials-stored-procedures5880631
Node: connector-net-tutorials-asp-roles5884494
Ref: connector-net-tutorials-authentication-type5890336
Ref: connector-net-tutorials-select-provider5890666
Ref: connector-net-tutorials-tables5890963
Ref: connector-net-tutorials-security-tab5891643
Ref: connector-net-tutorials-create-user5891996
Ref: connector-net-tutorials-users-roles-tables5892189
Node: connector-net-tutorials-asp-provider-session-state5892390
Node: connector-net-tutorials-asp-provider-profile5898897
Ref: connector-net-tutorials-asp-provider-profile-simple-app5902197
Node: connector-net-tutorials-entity-framework-winform-data-source5904602
Ref: connector-net-visual-studio-entity-framework-add-entity-data-model5906163
Ref: connector-net-visual-studio-entity-framework-entity-data-model-wizard-15906420
Ref: connector-net-visual-studio-entity-framework-entity-data-model-wizard-25906816
Ref: connector-net-visual-studio-entity-framework-entity-data-model-wizard-35907477
Ref: connector-net-visual-studio-entity-framework-entity-data-model-diagram5907600
Ref: connector-net-visual-studio-entity-framework-data-source-configuration-wizard-15908078
Ref: connector-net-visual-studio-entity-framework-data-source-configuration-wizard-25908375
Ref: connector-net-visual-studio-entity-framework-data-source-configuration-wizard-35908536
Ref: connector-net-visual-studio-entity-framework-data-sources5908843
Ref: connector-net-visual-studio-entity-framework-data-form-design5909338
Ref: connector-net-visual-studio-entity-framework-form-add-code5909803
Ref: connector-net-visual-studio-entity-framework-app-running-15909981
Ref: connector-net-visual-studio-entity-framework-save-enabled5910608
Ref: connector-net-visual-studio-entity-framework-form-add-code-save5910859
Node: connector-net-tutorials-entity-framework-databinding-linq-entities5911064
Ref: connector-net-visual-studio-entity-framework-tutorial-linq-15912483
Ref: connector-net-visual-studio-entity-framework-tutorial-linq-25912762
Ref: connector-net-visual-studio-entity-framework-tutorial-linq-35913091
Ref: connector-net-visual-studio-entity-framework-tutorial-linq-45913189
Ref: connector-net-visual-studio-entity-framework-tutorial-linq-55913341
Ref: connector-net-visual-studio-entity-framework-tutorial-linq-65917382
Ref: connector-net-visual-studio-entity-framework-tutorial-linq-75917551
Node: connector-net-tutorials-ssl5917762
Node: connector-net-tutorials-mysqlscript5924388
Node: connector-net-tutorials-mysqlscript-delimiter5930025
Node: connector-net-tutorials-efmodel-ddl5933895
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Node: connector-net-programming-getschema5946299
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Node: connector-net-programming-mysqlcommand5950564
Node: connector-net-programming-connection-pooling5953909
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Node: connector-net-programming-tracing-mysql6017962
Node: connector-net-programming-tracing-mysql-custom-listeners6025241
Node: connector-net-programming-bulk-loader6029149
Node: connector-net-connection-options6032720
Node: connector-net-ref6056054
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Node: connector-net-ref-mysqlclient-mysqlcommandconstructor16070456
Node: connector-net-ref-mysqlclient-mysqlcommandconstructor26071266
Node: connector-net-ref-mysqlclient-mysqlcommandconstructor36072049
Node: connector-net-ref-mysqlclient-mysqlconnection6072978
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Node: connector-net-ref-mysqlclient-mysqlconnectionconstructor16081562
Node: connector-net-ref-mysqlclient-mysqlconnectionconstructor26082407
Node: connector-net-ref-mysqlclient-mysqlconnection-connectionstring6083159
Node: connector-net-ref-mysqlclient-mysqlconnection-connectiontimeout6083935
Node: connector-net-ref-mysqlclient-mysqlconnection-database6084717
Node: connector-net-ref-mysqlclient-mysqlconnection-datasource6085441
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Node: connector-net-ref-mysqlclient-mysqltransaction6091006
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Node: connector-net-ref-mysqlclient-mysqltransaction-connection6094697
Node: connector-net-ref-mysqlclient-mysqltransaction-isolationlevel6096009
Node: connector-net-ref-mysqlclient-mysqltransaction-commit6097060
Node: connector-net-ref-mysqlclient-mysqltransaction-rollback6097779
Node: connector-net-ref-mysqlclient-mysqlconnection-begintransaction-overload-26098440
Node: connector-net-ref-mysqlclient-mysqlconnection-changedatabase6099331
Node: connector-net-ref-mysqlclient-mysqlconnection-close6100182
Node: connector-net-ref-mysqlclient-mysqlconnection-createcommand6100889
Node: connector-net-ref-mysqlclient-mysqlconnection-open6101550
Node: connector-net-ref-mysqlclient-mysqlconnection-ping6102240
Node: connector-net-ref-mysqlclient-mysqlconnection-infomessage6102871
Node: connector-net-ref-mysqlclient-mysqlinfomessageeventhandler6103671
Node: connector-net-ref-mysqlclient-mysqlinfomessageeventargs6104821
Node: connector-net-ref-mysqlclient-mysqlinfomessageeventargsmembers6106124
Node: connector-net-ref-mysqlclient-mysqlinfomessageeventargsconstructor6108625
Node: connector-net-ref-mysqlclient-mysqlinfomessageeventargs-errors6109449
Node: connector-net-ref-mysqlclient-mysqlerror6110151
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Node: connector-net-ref-mysqlclient-mysqlcommandconstructor46116721
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Node: connector-net-ref-mysqlclient-mysqlparametercollection6121740
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Node: connector-net-ref-mysqlclient-mysqlparameterconstructor66153512
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Node: connector-net-ref-mysqlclient-mysqlparametercollection-add-overload-26174542
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Node: connector-net-ref-mysqlclient-mysqldatareader-getint646238742
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Node: connector-net-ref-mysqlclient-mysqldatareader-getordinal6241155
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Node: connector-net-ref-mysqlclient-mysqldataadapter6267374
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Node: connector-net-ref-mysqlclient-mysqldataadapter-updatecommand16284367
Node: connector-net-ref-mysqlclient-mysqldataadapter-rowupdated6285041
Node: connector-net-ref-mysqlclient-mysqlrowupdatedeventhandler6287489
Node: connector-net-ref-mysqlclient-mysqlrowupdatedeventargs6288559
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Node: connector-net-ref-mysqlclient-mysqlrowupdatedeventargsconstructor6293139
Node: connector-net-ref-mysqlclient-mysqlrowupdatedeventargs-command16294474
Node: connector-net-ref-mysqlclient-mysqldataadapter-rowupdating6295155
Node: connector-net-ref-mysqlclient-mysqlrowupdatingeventhandler6297320
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Ref: qandaitem-B-10-1-147284106
Ref: qandaitem-B-10-1-157285186
Ref: qandaitem-B-10-1-167285999
Ref: qandaitem-B-10-1-177286396
Ref: qandaitem-B-10-1-187286682
Ref: qandaitem-B-10-1-197287400
Ref: qandaitem-B-10-1-207287894
Ref: qandaitem-B-10-1-217288166
Ref: qandaitem-B-10-1-227289302
Ref: qandaitem-B-10-1-237290530
Ref: qandaitem-B-10-1-247292545
Ref: qandaitem-B-10-1-257293447
Ref: qandaitem-B-10-1-267294083
Ref: qandaitem-B-10-1-277295741
Ref: qandaitem-B-10-1-287296909
Ref: qandaitem-B-10-1-297299243
Ref: qandaitem-B-10-1-307299479
Ref: qandaitem-B-10-1-317299955
Ref: qandaitem-B-10-1-327300460
Ref: qandaitem-B-10-1-337301162
Ref: qandaitem-B-10-1-347301534
Ref: qandaitem-B-10-1-357302159
Ref: qandaitem-B-10-1-367302434
Ref: qandaitem-B-10-1-377302928
Node: faqs-cjk7304574
Ref: qandaitem-B-11-1-17306821
Ref: qandaitem-B-11-1-27309676
Ref: qandaitem-B-11-1-37315283
Ref: qandaitem-B-11-1-47316290
Ref: qandaitem-B-11-1-57319168
Ref: qandaitem-B-11-1-67319485
Ref: qandaitem-B-11-1-77319899
Ref: qandaitem-B-11-1-87320136
Ref: qandaitem-B-11-1-97321046
Ref: qandaitem-B-11-1-107322800
Ref: qandaitem-B-11-1-117325519
Ref: qandaitem-B-11-1-127329999
Ref: qandaitem-B-11-1-137331904
Ref: qandaitem-B-11-1-147334756
Ref: qandaitem-B-11-1-157338100
Ref: qandaitem-B-11-1-167340045
Ref: qandaitem-B-11-1-177341241
Ref: qandaitem-B-11-1-187341713
Ref: qandaitem-B-11-1-197342338
Ref: qandaitem-B-11-1-207342658
Node: faqs-connectors-apis7343115
Node: faqs-replication7343643
Node: faqs-mysql-drbd-heartbeat7343937
Node: faqs-drbd7344706
Ref: qandaitem-B-14-1-1-17345446
Ref: qandaitem-B-14-1-1-27345903
Ref: qandaitem-B-14-1-1-37346402
Ref: qandaitem-B-14-1-1-47346475
Ref: qandaitem-B-14-1-1-57346574
Ref: qandaitem-B-14-1-1-67346746
Node: drbd-linux-heartbeat7346887
Ref: qandaitem-B-14-2-1-17347402
Ref: qandaitem-B-14-2-1-27347496
Ref: qandaitem-B-14-2-1-37347607
Node: drbd-architecture7347791
Ref: qandaitem-B-14-3-1-17348611
Ref: qandaitem-B-14-3-1-27348780
Ref: qandaitem-B-14-3-1-37349018
Ref: qandaitem-B-14-3-1-47349463
Ref: qandaitem-B-14-3-1-57349909
Ref: qandaitem-B-14-3-1-67350072
Ref: qandaitem-B-14-3-1-77350234
Node: drbd-mysql-replication-scale7350679
Ref: qandaitem-B-14-4-1-17351275
Ref: qandaitem-B-14-4-1-27351747
Ref: qandaitem-B-14-4-1-37352210
Node: drbd-file-systems7353298
Ref: qandaitem-B-14-5-1-17353688
Node: drbd-lvm7353802
Ref: qandaitem-B-14-6-1-17354311
Ref: qandaitem-B-14-6-1-27354561
Ref: qandaitem-B-14-6-1-37354878
Node: drbd-virtualization7355091
Ref: qandaitem-B-14-7-1-17355523
Ref: qandaitem-B-14-7-1-27355635
Node: drbd-security7355867
Ref: qandaitem-B-14-8-1-17356321
Ref: qandaitem-B-14-8-1-27356515
Node: drbd-system-requirements7356656
Ref: qandaitem-B-14-9-1-17357202
Ref: qandaitem-B-14-9-1-27358065
Ref: qandaitem-B-14-9-1-37358398
Node: drbd-support-consulting7358594
Ref: qandaitem-B-14-10-1-17359486
Ref: qandaitem-B-14-10-1-27359832
Ref: qandaitem-B-14-10-1-37360405
Ref: qandaitem-B-14-10-1-47360662
Ref: qandaitem-B-14-10-1-57360943
Ref: qandaitem-B-14-10-1-67361075
Node: error-handling7361291
Node: error-sources7362160
Node: error-types7363886
Node: error-messages-server7365729
Ref: error_er_hashchk7368016
Ref: error_er_nisamchk7368093
Ref: error_er_no7368171
Ref: error_er_yes7368238
Ref: error_er_cant_create_file7368307
Ref: error_er_cant_create_table7368420
Ref: error_er_cant_create_db7368535
Ref: error_er_db_create_exists7368650
Ref: error_er_db_drop_exists7368772
Ref: error_er_db_drop_delete7368897
Ref: error_er_db_drop_rmdir7369028
Ref: error_er_cant_delete_file7369157
Ref: error_er_cant_find_system_rec7369271
Ref: error_er_cant_get_stat7369387
Ref: error_er_cant_get_wd7369499
Ref: error_er_cant_lock7369612
Ref: error_er_cant_open_file7369711
Ref: error_er_file_not_found7369821
Ref: error_er_cant_read_dir7369931
Ref: error_er_cant_set_wd7370041
Ref: error_er_checkread7370151
Ref: error_er_disk_full7370271
Ref: error_er_dup_key7370400
Ref: error_er_error_on_close7370510
Ref: error_er_error_on_read7370621
Ref: error_er_error_on_rename7370732
Ref: error_er_error_on_write7370853
Ref: error_er_file_used7370965
Ref: error_er_filsort_abort7371066
Ref: error_er_form_not_found7371154
Ref: error_er_get_errno7371263
Ref: error_er_illegal_ha7371367
Ref: error_er_key_not_found7371494
Ref: error_er_not_form_file7371595
Ref: error_er_not_keyfile7371706
Ref: error_er_old_keyfile7371831
Ref: error_er_open_as_readonly7371944
Ref: error_er_outofmemory7372046
Ref: error_er_out_of_sortmemory7372186
Ref: error_er_unexpected_eof7372318
Ref: error_er_con_count_error7372450
Ref: error_er_out_of_resources7372548
Ref: error_er_bad_host_error7372819
Ref: error_er_handshake_error7372931
Ref: error_er_dbaccess_denied_error7373022
Ref: error_er_access_denied_error7373155
Ref: error_er_no_db_error7373290
Ref: error_er_unknown_com_error7373384
Ref: error_er_bad_null_error7373479
Ref: error_er_bad_db_error7373582
Ref: error_er_table_exists_error7373678
Ref: error_er_bad_table_error7373784
Ref: error_er_non_uniq_error7373880
Ref: error_er_server_shutdown7373987
Ref: error_er_bad_field_error7374092
Ref: error_er_wrong_field_with_group7374197
Ref: error_er_wrong_group_field7374304
Ref: error_er_wrong_sum_select7374403
Ref: error_er_wrong_value_count7374539
Ref: error_er_too_long_ident7374657
Ref: error_er_dup_fieldname7374766
Ref: error_er_dup_keyname7374868
Ref: error_er_dup_entry7374965
Ref: error_er_wrong_field_spec7375068
Ref: error_er_parse_error7375189
Ref: error_er_empty_query7375286
Ref: error_er_nonuniq_table7375375
Ref: error_er_invalid_default7375479
Ref: error_er_multiple_pri_key7375587
Ref: error_er_too_many_keys7375694
Ref: error_er_too_many_key_parts7375814
Ref: error_er_too_long_key7375945
Ref: error_er_key_column_does_not_exits7376074
Ref: error_er_blob_used_as_key7376200
Ref: error_er_too_big_fieldlength7376360
Ref: error_er_wrong_auto_key7376522
Ref: error_er_ready7376697
Ref: error_er_normal_shutdown7376832
Ref: error_er_got_signal7376929
Ref: error_er_shutdown_complete7377030
Ref: error_er_forcing_close7377131
Ref: error_er_ipsock_error7377249
Ref: error_er_no_such_index7377346
Ref: error_er_wrong_field_terminators7377504
Ref: error_er_blobs_and_no_terminated7377661
Ref: error_er_textfile_not_readable7377827
Ref: error_er_file_exists_error7377985
Ref: error_er_load_info7378089
Ref: error_er_alter_info7378213
Ref: error_er_wrong_sub_key7378314
Ref: error_er_cant_remove_all_fields7378556
Ref: error_er_cant_drop_field_or_key7378715
Ref: error_er_insert_info7378845
Ref: error_er_update_table_used7378961
Ref: error_er_no_such_thread7379107
Ref: error_er_kill_denied_error7379206
Ref: error_er_no_tables_used7379317
Ref: error_er_too_big_set7379408
Ref: error_er_no_unique_logfile7379520
Ref: error_er_table_not_locked_for_write7379647
Ref: error_er_table_not_locked7379800
Ref: error_er_blob_cant_have_default7379921
Ref: error_er_wrong_db_name7380054
Ref: error_er_wrong_table_name7380158
Ref: error_er_too_big_select7380262
Ref: error_er_unknown_error7380499
Ref: error_er_unknown_procedure7380588
Ref: error_er_wrong_paramcount_to_procedure7380690
Ref: error_er_wrong_parameters_to_procedure7380830
Ref: error_er_unknown_table7380965
Ref: error_er_field_specified_twice7381065
Ref: error_er_invalid_group_func_use7381176
Ref: error_er_unsupported_extension7381290
Ref: error_er_table_must_have_columns7381448
Ref: error_er_record_file_full7381569
Ref: error_er_unknown_character_set7381670
Ref: error_er_too_many_tables7381781
Ref: error_er_too_many_fields7381914
Ref: error_er_too_big_rowsize7382008
Ref: error_er_stack_overrun7382238
Ref: error_er_wrong_outer_join7382433
Ref: error_er_null_column_in_index7382581
Ref: error_er_cant_find_udf7382740
Ref: error_er_cant_initialize_udf7382840
Ref: error_er_udf_no_paths7382956
Ref: error_er_udf_exists7383066
Ref: error_er_cant_open_library7383167
Ref: error_er_cant_find_dl_entry7383292
Ref: error_er_function_not_defined7383408
Ref: error_er_host_is_blocked7383519
Ref: error_er_host_not_privileged7383695
Ref: error_er_password_anonymous_user7383833
Ref: error_er_password_not_allowed7384020
Ref: error_er_password_no_match7384213
Ref: error_er_update_info7384338
Ref: error_er_cant_create_thread7384456
Ref: error_er_wrong_value_count_on_row7384683
Ref: error_er_cant_reopen_table7384819
Ref: error_er_invalid_use_of_null7384923
Ref: error_er_regexp_error7385030
Ref: error_er_mix_of_group_func_and_fields7385131
Ref: error_er_nonexisting_grant7385345
Ref: error_er_tableaccess_denied_error7385482
Ref: error_er_columnaccess_denied_error7385619
Ref: error_er_illegal_grant_for_table7385777
Ref: error_er_grant_wrong_host_or_user7385959
Ref: error_er_no_such_table7386092
Ref: error_er_nonexisting_table_grant7386195
Ref: error_er_not_allowed_command7386357
Ref: error_er_syntax_error7386494
Ref: error_er_delayed_cant_change_lock7386707
Ref: error_er_too_many_delayed_threads7386861
Ref: error_er_aborting_connection7386979
Ref: error_er_net_packet_too_large7387111
Ref: error_er_net_read_error_from_pipe7387245
Ref: error_er_net_fcntl_error7387373
Ref: error_er_net_packets_out_of_order7387476
Ref: error_er_net_uncompress_error7387587
Ref: error_er_net_read_error7387710
Ref: error_er_net_read_interrupted7387829
Ref: error_er_net_error_on_write7387953
Ref: error_er_net_write_interrupted7388076
Ref: error_er_too_long_string7388201
Ref: error_er_table_cant_handle_blob7388334
Ref: error_er_table_cant_handle_auto_increment7388472
Ref: error_er_delayed_insert_table_locked7388630
Ref: error_er_wrong_column_name7388807
Ref: error_er_wrong_key_column7388913
Ref: error_er_wrong_mrg_table7389039
Ref: error_er_dup_unique7389221
Ref: error_er_blob_key_without_length7389350
Ref: error_er_primary_cant_have_null7389509
Ref: error_er_too_many_rows7389689
Ref: error_er_requires_primary_key7389802
Ref: error_er_no_raid_compiled7389923
Ref: error_er_update_without_key_in_safe_mode7390057
Ref: error_er_key_does_not_exits7390262
Ref: error_er_check_no_such_table7390379
Ref: error_er_check_not_implemented7390477
Ref: error_er_cant_do_this_during_an_transaction7390612
Ref: error_er_error_during_commit7390779
Ref: error_er_error_during_rollback7390887
Ref: error_er_error_during_flush_logs7390999
Ref: error_er_error_during_checkpoint7391115
Ref: error_er_new_aborting_connection7391231
Ref: error_er_dump_not_implemented7391383
Ref: error_er_flush_master_binlog_closed7391538
Ref: error_er_index_rebuild7391661
Ref: error_er_master7391785
Ref: error_er_master_net_read7391877
Ref: error_er_master_net_write7391984
Ref: error_er_ft_matching_key_not_found7392090
Ref: error_er_lock_or_active_transaction7392228
Ref: error_er_unknown_system_variable7392416
Ref: error_er_crashed_on_usage7392530
Ref: error_er_crashed_on_repair7392663
Ref: error_er_warning_not_complete_rollback7392815
Ref: error_er_trans_cache_full7392978
Ref: error_er_slave_must_stop7393199
Ref: error_er_slave_not_running7393359
Ref: error_er_bad_slave7393519
Ref: error_er_master_info7393678
Ref: error_er_slave_thread7393856
Ref: error_er_too_many_user_connections7393984
Ref: error_er_set_constants_only7394148
Ref: error_er_lock_wait_timeout7394275
Ref: error_er_lock_table_full7394409
Ref: error_er_read_only_transaction7394540
Ref: error_er_drop_db_with_read_lock7394698
Ref: error_er_create_db_with_read_lock7394854
Ref: error_er_wrong_arguments7395014
Ref: error_er_no_permission_to_create_user7395117
Ref: error_er_union_tables_in_different_dir7395257
Ref: error_er_lock_deadlock7395432
Ref: error_er_table_cant_handle_ft7395579
Ref: error_er_cannot_add_foreign7395714
Ref: error_er_no_referenced_row7395828
Ref: error_er_row_is_referenced7395977
Ref: error_er_connect_to_master7396130
Ref: error_er_query_on_master7396240
Ref: error_er_error_when_executing_command7396351
Ref: error_er_wrong_usage7396482
Ref: error_er_wrong_number_of_columns_in_select7396584
Ref: error_er_cant_update_with_readlock7396751
Ref: error_er_mixing_not_allowed7396908
Ref: error_er_dup_argument7397058
Ref: error_er_user_limit_reached7397168
Ref: error_er_specific_access_denied_error7397315
Ref: error_er_local_variable7397475
Ref: error_er_global_variable7397626
Ref: error_er_no_default7397777
Ref: error_er_wrong_value_for_var7397892
Ref: error_er_wrong_type_for_var7398021
Ref: error_er_var_cant_be_read7398142
Ref: error_er_cant_use_option_here7398260
Ref: error_er_not_supported_yet7398376
Ref: error_er_master_fatal_error_reading_binlog7398502
Ref: error_er_slave_ignored_table7398678
Ref: error_er_incorrect_global_local_var7398834
Ref: error_er_wrong_fk_def7398953
Ref: error_er_key_ref_do_not_match_table_ref7399073
Ref: error_er_operand_columns7399216
Ref: error_er_subquery_no_1_row7399329
Ref: error_er_unknown_stmt_handler7399441
Ref: error_er_corrupt_help_db7399577
Ref: error_er_cyclic_reference7399697
Ref: error_er_auto_convert7399806
Ref: error_er_illegal_reference7399917
Ref: error_er_derived_must_have_alias7400030
Ref: error_er_select_reduced7400159
Ref: error_er_tablename_not_allowed_here7400277
Ref: error_er_not_supported_auth_mode7400421
Ref: error_er_spatial_cant_have_null7400612
Ref: error_er_collation_charset_mismatch7400742
Ref: error_er_slave_was_running7400881
Ref: error_er_slave_was_not_running7400985
Ref: error_er_too_big_for_uncompress7401099
Ref: error_er_zlib_z_mem_error7401299
Ref: error_er_zlib_z_buf_error7401401
Ref: error_er_zlib_z_data_error7401581
Ref: error_er_cut_value_group_concat7401687
Ref: error_er_warn_too_few_records7401809
Ref: error_er_warn_too_many_records7401936
Ref: error_er_warn_null_to_notnull7402100
Ref: error_er_warn_data_out_of_range7402283
Ref: error_warn_data_truncated7402422
Ref: error_er_warn_using_other_handler7402542
Ref: error_er_cant_aggregate_2collations7402667
Ref: error_er_drop_user7402825
Ref: error_er_revoke_grants7402943
Ref: error_er_cant_aggregate_3collations7403090
Ref: error_er_cant_aggregate_ncollations7403254
Ref: error_er_variable_is_not_struct7403387
Ref: error_er_unknown_collation7403556
Ref: error_er_slave_ignored_ssl_params7403659
Ref: error_er_server_is_in_secure_auth_mode7403916
Ref: error_er_warn_field_resolved7404155
Ref: error_er_bad_slave_until_cond7404314
Ref: error_er_missing_skip_slave7404472
Ref: error_er_until_cond_ignored7404746
Ref: error_er_wrong_name_for_index7404892
Ref: error_er_wrong_name_for_catalog7405000
Ref: error_er_warn_qc_resize7405112
Ref: error_er_bad_ft_column7405257
Ref: error_er_unknown_key_cache7405377
Ref: error_er_warn_hostname_wont_work7405479
Ref: error_er_unknown_storage_engine7405677
Ref: error_er_warn_deprecated_syntax7405787
Ref: error_er_non_updatable_table7405908
Ref: error_er_feature_disabled7406036
Ref: error_er_option_prevents_statement7406199
Ref: error_er_duplicated_value_in_type7406374
Ref: error_er_truncated_wrong_value7406504
Ref: error_er_too_much_auto_timestamp_cols7406622
Ref: error_er_invalid_on_update7406848
Ref: error_er_unsupported_ps7406968
Ref: error_er_get_errmsg7407118
Ref: error_er_get_temporary_errmsg7407216
Ref: error_er_unknown_time_zone7407334
Ref: error_er_warn_invalid_timestamp7407450
Ref: error_er_invalid_character_string7407584
Ref: error_er_warn_allowed_packet_overflowed7407704
Ref: error_er_conflicting_declarations7407874
Ref: error_er_sp_no_recursive_create7408004
Ref: error_er_sp_already_exists7408141
Ref: error_er_sp_does_not_exist7408241
Ref: error_er_sp_drop_failed7408341
Ref: error_er_sp_store_failed7408438
Ref: error_er_sp_lilabel_mismatch7408538
Ref: error_er_sp_label_redefine7408649
Ref: error_er_sp_label_mismatch7408748
Ref: error_er_sp_uninit_var7408854
Ref: error_er_sp_badselect7408968
Ref: error_er_sp_badreturn7409107
Ref: error_er_sp_badstatement7409218
Ref: error_er_update_log_deprecated_ignored7409334
Ref: error_er_update_log_deprecated_translated7409532
Ref: error_er_query_interrupted7409755
Ref: error_er_sp_wrong_no_of_args7409866
Ref: error_er_sp_cond_mismatch7410013
Ref: error_er_sp_noreturn7410115
Ref: error_er_sp_noreturnend7410219
Ref: error_er_sp_bad_cursor_query7410328
Ref: error_er_sp_bad_cursor_select7410443
Ref: error_er_sp_cursor_mismatch7410558
Ref: error_er_sp_cursor_already_open7410659
Ref: error_er_sp_cursor_not_open7410766
Ref: error_er_sp_undeclared_var7410865
Ref: error_er_sp_wrong_no_of_fetch_args7410968
Ref: error_er_sp_fetch_no_data7411091
Ref: error_er_sp_dup_param7411221
Ref: error_er_sp_dup_var7411319
Ref: error_er_sp_dup_cond7411414
Ref: error_er_sp_dup_curs7411511
Ref: error_er_sp_cant_alter7411605
Ref: error_er_sp_subselect_nyi7411702
Ref: error_er_stmt_not_allowed_in_sf_or_trg7411810
Ref: error_er_sp_varcond_after_curshndlr7411954
Ref: error_er_sp_cursor_after_handler7412117
Ref: error_er_sp_case_not_found7412247
Ref: error_er_fparser_too_big_file7412360
Ref: error_er_fparser_bad_header7412477
Ref: error_er_fparser_eof_in_comment7412597
Ref: error_er_fparser_error_in_parameter7412731
Ref: error_er_fparser_eof_in_unknown_parameter7412867
Ref: error_er_view_no_explain7413032
Ref: error_er_frm_unknown_type7413186
Ref: error_er_wrong_object7413310
Ref: error_er_nonupdateable_column7413402
Ref: error_er_view_select_derived7413513
Ref: error_er_view_select_clause7413647
Ref: error_er_view_select_variable7413764
Ref: error_er_view_select_tmptable7413893
Ref: error_er_view_wrong_list7414022
Ref: error_er_warn_view_merge7414169
Ref: error_er_warn_view_without_key7414329
Ref: error_er_view_invalid7414489
Ref: error_er_sp_no_drop_sp7414688
Ref: error_er_sp_goto_in_hndlr7414828
Ref: error_er_trg_already_exists7414956
Ref: error_er_trg_does_not_exist7415059
Ref: error_er_trg_on_view_or_temp_table7415162
Ref: error_er_trg_cant_change_row7415291
Ref: error_er_trg_no_such_row_in_trg7415419
Ref: error_er_no_default_for_field7415536
Ref: error_er_division_by_zero7415658
Ref: error_er_truncated_wrong_value_for_field7415750
Ref: error_er_illegal_value_for_type7415900
Ref: error_er_view_nonupd_check7416027
Ref: error_er_view_check_failed7416149
Ref: error_er_procaccess_denied_error7416256
Ref: error_er_relay_log_fail7416394
Ref: error_er_passwd_length7416504
Ref: error_er_unknown_target_binlog7416633
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Ref: error_er_binlog_purge_prohibited7416869
Ref: error_er_fseek_fail7417004
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Ref: error_er_log_in_use7417207
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Ref: error_er_relay_log_init7417435
Ref: error_er_no_binary_logging7417554
Ref: error_er_reserved_syntax7417666
Ref: error_er_wsas_failed7417818
Ref: error_er_diff_groups_proc7417909
Ref: error_er_no_group_for_proc7418037
Ref: error_er_order_with_proc7418161
Ref: error_er_logging_prohibit_changing_of7418281
Ref: error_er_no_file_mapping7418449
Ref: error_er_wrong_magic7418556
Ref: error_er_ps_many_param7418647
Ref: error_er_key_part_07418772
Ref: error_er_view_checksum7418877
Ref: error_er_view_multiupdate7418978
Ref: error_er_view_no_insert_field_list7419129
Ref: error_er_view_delete_merge_view7419274
Ref: error_er_cannot_user7419396
Ref: error_er_xaer_nota7419496
Ref: error_er_xaer_inval7419590
Ref: error_er_xaer_rmfail7419717
Ref: error_er_xaer_outside7419882
Ref: error_er_xaer_rmerr7420015
Ref: error_er_xa_rbrollback7420185
Ref: error_er_nonexisting_proc_grant7420310
Ref: error_er_proc_auto_grant_fail7420473
Ref: error_er_proc_auto_revoke_fail7420608
Ref: error_er_data_too_long7420742
Ref: error_er_sp_bad_sqlstate7420858
Ref: error_er_startup7420954
Ref: error_er_load_from_fixed_size_rows_to_var7421094
Ref: error_er_cant_create_user_with_grant7421258
Ref: error_er_wrong_value_for_type7421395
Ref: error_er_table_def_changed7421518
Ref: error_er_sp_dup_handler7421652
Ref: error_er_sp_not_var_arg7421773
Ref: error_er_sp_no_retset7421953
Ref: error_er_cant_create_geometry_object7422072
Ref: error_er_failed_routine_break_binlog7422234
Ref: error_er_binlog_unsafe_routine7422528
Ref: error_er_binlog_create_routine_need_super7422823
Ref: error_er_exec_stmt_with_open_cursor7423079
Ref: error_er_stmt_has_no_open_cursor7423294
Ref: error_er_commit_not_allowed_in_sf_or_trg7423419
Ref: error_er_no_default_for_view_field7423596
Ref: error_er_sp_no_recursion7423756
Ref: error_er_too_big_scale7423890
Ref: error_er_too_big_precision7424030
Ref: error_er_m_bigger_than_d7424179
Ref: error_er_wrong_lock_of_system_table7424336
Ref: error_er_connect_to_foreign_data_source7424503
Ref: error_er_query_on_foreign_data_source7424645
Ref: error_er_foreign_data_source_doesnt_exist7424836
Ref: error_er_foreign_data_string_invalid_cant_create7425030
Ref: error_er_foreign_data_string_invalid7425239
Ref: error_er_cant_create_federated_table7425401
Ref: error_er_trg_in_wrong_schema7425547
Ref: error_er_stack_overrun_need_more7425652
Ref: error_er_too_long_body7425885
Ref: error_er_warn_cant_drop_default_keycache7425994
Ref: error_er_too_big_displaywidth7426121
Ref: error_er_xaer_dupid7426258
Ref: error_er_datetime_function_overflow7426365
Ref: error_er_cant_update_used_table_in_sf_or_trg7426490
Ref: error_er_view_prevent_update7426737
Ref: error_er_ps_no_recursion7426889
Ref: error_er_sp_cant_set_autocommit7427142
Ref: error_er_malformed_definer7427295
Ref: error_er_view_frm_no_user7427405
Ref: error_er_view_other_user7427609
Ref: error_er_no_such_user7427761
Ref: error_er_forbid_schema_change7427868
Ref: error_er_row_is_referenced_27428000
Ref: error_er_no_referenced_row_27428160
Ref: error_er_sp_bad_var_shadow7428316
Ref: error_er_trg_no_definer7428447
Ref: error_er_old_file_format7428716
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Ref: error_er_sp_proc_table_corrupt7429042
Ref: error_er_sp_wrong_name7429239
Ref: error_er_table_needs_upgrade7429342
Ref: error_er_sp_no_aggregate7429493
Ref: error_er_max_prepared_stmt_count_reached7429618
Ref: error_er_view_recursive7429800
Ref: error_er_non_grouping_field_used7429910
Ref: error_er_table_cant_handle_spkeys7430040
Ref: error_er_no_triggers_on_system_schema7430178
Ref: error_er_removed_spaces7430318
Ref: error_er_autoinc_read_failed7430436
Ref: error_er_username7430573
Ref: error_er_hostname7430653
Ref: error_er_wrong_string_length7430733
Ref: error_er_non_insertable_table7430880
Ref: error_er_admin_wrong_mrg_table7431015
Ref: error_er_too_high_level_of_nesting_for_select7431176
Ref: error_er_name_becomes_empty7431316
Ref: error_er_ambiguous_field_term7431419
Ref: error_er_load_data_invalid_column7431625
Ref: error_er_log_purge_no_file7431754
Ref: error_er_xa_rbtimeout7431867
Ref: error_er_xa_rbdeadlock7432010
Ref: error_er_too_many_concurrent_trxs7432163
Node: error-messages-client7432284
Ref: error_cr_unknown_error7433044
Ref: error_cr_socket_create_error7433121
Ref: error_cr_connection_error7433214
Ref: error_cr_conn_host_error7433340
Ref: error_cr_ipsock_error7433442
Ref: error_cr_unknown_host7433530
Ref: error_cr_server_gone_error7433622
Ref: error_cr_version_error7433710
Ref: error_cr_out_of_memory7433832
Ref: error_cr_wrong_host_info7433920
Ref: error_cr_localhost_connection7433995
Ref: error_cr_tcp_connection7434085
Ref: error_cr_server_handshake_err7434157
Ref: error_cr_server_lost7434247
Ref: error_cr_commands_out_of_sync7434347
Ref: error_cr_namedpipe_connection7434464
Ref: error_cr_namedpipewait_error7434543
Ref: error_cr_namedpipeopen_error7434659
Ref: error_cr_namedpipesetstate_error7434771
Ref: error_cr_cant_read_charset7434895
Ref: error_cr_net_packet_too_large7435001
Ref: error_cr_embedded_connection7435115
Ref: error_cr_probe_slave_status7435194
Ref: error_cr_probe_slave_hosts7435284
Ref: error_cr_probe_slave_connect7435372
Ref: error_cr_probe_master_connect7435462
Ref: error_cr_ssl_connection_error7435554
Ref: error_cr_malformed_packet7435639
Ref: error_cr_wrong_license7435716
Ref: error_cr_null_pointer7435862
Ref: error_cr_no_prepare_stmt7435946
Ref: error_cr_params_not_bound7436028
Ref: error_cr_data_truncated7436142
Ref: error_cr_no_parameters_exists7436215
Ref: error_cr_invalid_parameter_no7436316
Ref: error_cr_invalid_buffer_use7436405
Ref: error_cr_unsupported_param_type7436546
Ref: error_cr_shared_memory_connection7436662
Ref: error_cr_shared_memory_connect_request_error7436748
Ref: error_cr_shared_memory_connect_answer_error7436902
Ref: error_cr_shared_memory_connect_file_map_error7437054
Ref: error_cr_shared_memory_connect_map_error7437210
Ref: error_cr_shared_memory_file_map_error7437367
Ref: error_cr_shared_memory_map_error7437515
Ref: error_cr_shared_memory_event_error7437664
Ref: error_cr_shared_memory_connect_abandoned_error7437803
Ref: error_cr_shared_memory_connect_set_error7437938
Ref: error_cr_conn_unknow_protocol7438086
Ref: error_cr_invalid_conn_handle7438176
Ref: error_cr_secure_auth7438265
Ref: error_cr_fetch_canceled7438428
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Ref: error_cr_no_stmt_metadata7438638
Ref: error_cr_no_result_set7438738
Ref: error_cr_not_implemented7438881
Ref: error_cr_server_lost_extended7438976
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